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The diffuse seismicity of the Sierra Nevada of Santa Marta, the Perijá Range, and south of the La Guajira peninsula, Colombia and Venezuela: Result of the convergence between Caribbean plate and the South American margin during the Late Neogene?
NASA Astrophysics Data System (ADS)
Chicangana, G.; Pedraza, P.; Mora-paez, H.; Ordonez Aristizabal, C. O.; Vargas-Jimenez, C. A.; Kammer, A.
A diffuse low deep microseismicity located overall between the Guajira peninsula and the Sierra Nevada de Santa Marta (SNSM) was registered with the recent installation (2008 to Present) of three seismological stations in northeastern Colombia by the Colombian Seismological Network (RSNC), but mainly with the Uribia station in (the) central region of La Guajira peninsula, The microseismicity is characterized by a great population of events with 1.2 < Ml < 3.0. and few events of 3.0 < Ml < 4.0 that sporadically occur. The poor number of seismological stations in this region of Colombia impedes to locate the origin of the local seismicity; however, this seismic activity is associated to the tectonic activity of the Oca fault because with the GPS displacement analysis, neotectonics evidence found in faults traces associated to the Oca fault and the historical earthquake that affected the Colombian city of Santa Marta in 1834, lead us to conclude this. This is a big cortical fault that sets the limit between La Guajira peninsula and the SNSM. Its cortical characteristics were verified from geological data together with gravimetric and seismic exploration. The SNSM limits toward the southeast with the Cesar - Ranchería basin, and this basin in turn limits with the Perijá Range that is localized in the Colombia - Venezuela border. The SNSM, Cesar - Ranchería basin and Perijá Range limit toward the southwest with the Bucaramanga - Santa Marta fault (BSMF), the Oca fault toward the north, and Perijá - El Tigre fault toward the southeast defining a pyramidal orogenic complex. Using remote sensing images data with geological and regional geophysical information, we proposed that this orogenic complex was originated as a result of the Panama arc with the northwestern South America accretion. The final adjustment of the Caribbean plate (CP) between North America and South America during the Late Neogene produced the big cortical faults systems activation like Oca - Moron
The background notes by the U.S. State Department on Venezuela emphasize the unique economic conditions in this oil-rich nation, and include information on its people, geography, history, government politics, defense and foreign relations. Venezuela, located on the north coast of South America, has 17,791,000 people, growing at a rate of 2.7%. Infant mortality is 2.7/1000, and life expectancy is 70 years. Geography ranges from the scarcely populated highlands between the Orinoco river and Guyana, the Orinoco plains, to the populated Andes mountains and coast. 80% of the population is urban. Literacy is a priority at 88.4%; Technical and university education is increasing; emigration from other countries is common because of relatively good working conditions. Venezuela has a long history of self government, having become independent in 1921. Now the democratic constitutional government is effective in improving both internal and regional development and human rights. The economy is based on oil production and refining, as well as steel and aluminum, all nationalized industries. Self-sufficiency in agriculture is a national goal. Because of the rapid population growth rate, however, per capita income and GNP are stagnating. PMID:12177927
15,000-yr pollen record of vegetation change in the high altitude tropical Andes at Laguna Verde Alta, Venezuela
NASA Astrophysics Data System (ADS)
Rull, Valentí; Abbott, Mark B.; Polissar, Pratigya J.; Wolfe, Alexander P.; Bezada, Maximiliano; Bradley, Raymond S.
Pollen analysis of sediments from a high-altitude (4215 m), Neotropical (9°N) Andean lake was conducted in order to reconstruct local and regional vegetation dynamics since deglaciation. Although deglaciation commenced ˜15,500 cal yr B.P., the area around the Laguna Verde Alta (LVA) remained a periglacial desert, practically unvegetated, until about 11,000 cal yr B.P. At this time, a lycopod assemblage bearing no modern analog colonized the superpáramo. Although this community persisted until ˜6000 cal yr B.P., it began to decline somewhat earlier, in synchrony with cooling following the Holocene thermal maximum of the Northern Hemisphere. At this time, the pioneer assemblage was replaced by a low-diversity superpáramo community that became established ˜9000 cal yr B.P. This replacement coincides with regional declines in temperature and/or available moisture. Modern, more diverse superpáramo assemblages were not established until ˜4600 cal yr B.P., and were accompanied by a dramatic decline in Alnus, probably the result of factors associated with climate, humans, or both. Pollen influx from upper Andean forests is remarkably higher than expected during the Late Glacial and early to middle Holocene, especially between 14,000 and 12,600 cal yr B.P., when unparalleled high values are recorded. We propose that intensification of upslope orographic winds transported lower elevation forest pollen to the superpáramo, causing the apparent increase in tree pollen at high altitude. The association between increased forest pollen and summer insolation at this time suggests a causal link; however, further work is needed to clarify this relationship.
77 FR 29633 - Alta Wind VII, LLC, Alta Wind IX, LLC, Alta Wind X, LLC, Alta Wind XI, LLC, Alta Wind XII, LLC...
Federal Register 2010, 2011, 2012, 2013, 2014
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[Commercial capture with long line in the exclusive economic zone in La Guajira, Colombian Caribbean Sea].
Alvarez-León, Ricardo
Pelagic fish were collected with long line in the 20-22 degrees C isotherms from 1986 to 1988 off Guajira, Colombia. Thirteen species of pelagic fish were found including four new records: Lampris guttatus, Lepidocybium flavobrunneum, Tetrapturus pfluegeri, Eumegistius brevorti. The occurrence of the orca (Orcinus orca Linnaeus) is confirmed in the Colombian Caribbean waters. PMID:12298249
A physical view of La Guajira Upwelling System, Colombian Basin, Caribbean Sea
NASA Astrophysics Data System (ADS)
Bernal, G.; Beier, E.; Barton, E. D.; Ruiz-Ochoa, M.; Correa, J. G.
La Guajira Peninsula lies within a large upwelling system along the South Caribbean Coast, created by the NE trade winds. In this location, sea surface temperature (SST) exhibits the lowest mean value and the highest variability in the whole Colombian Basin. The seasonal variation of SST explains up to 75 % of the total variability. La Guajira coastal zone also experiences the highest values of wind stress and wind stress curl, with the greatest annual and semiannual variability in the Colombian Basin. It has been shown that wind stress curl enhances the upwelling over the region. Near 90% of the variability of SST in La Guajira can be explained by the seasonality plus the first three EOFs interannual modes: the first, synchronous throughout the Basin, is dominant, and consists of a uniform interannual variation in phase with the North Tropical Atlantic Index; the second co-varies strongly with the second mode of wind stress curl; and the third reflects the role of the vertical atmospheric circulation cell associated with the Caribbean Low Level Jet off Central America. The inclusion of wind stress curl with its maximum offshore of La Guajira explains in part the extension of cool coastal water into the Colombian Basin, with advection in filaments, eddies and meanders. In order to complement the physical knowledge of La Guajira upwelling system, an analysis of water masses, sea surface height, Ekman suction, Ekman transport and coastal upwelling index (CUI) was performed. Hydrographic data was obtained from gridded climatologies from the National Oceanographic Data Center (WOD01); sea surface height anomalies from the Archiving, Validation, and Interpretation of Satellite Oceanography (AVISO) data; and wind data from the Cross-Calibrated Multi-Platform Ocean Surface Wind Velocity Product for Meteorological and Oceanographic Applications (CCMP). The upwelling forms a local water mass, La Guajira surface water (LGSW), with the mixing of subtropical underwater and
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[Composition, abundance and distribution of populations of commercially important gastropods in La Guajira, Colombian Caribbean].
Nieto-Bernal, Ramón; Luis, Chasqui; Rodriguez, Angélica María; Castro, Erick; Gil-Agudelo, Diego L
In the continental Colombian Caribbean the conch resource exploitation and the status of snails populations has been poorly studied, which are reflected in the lack of fisheries management. This study assesses composition, population density and distribution of the gastropods species that make conch resource in La Guajira region. Underwater visual censuses for snails were performed between September-November 2009 in 145100x4m (400m2) transects, spanning a total area of 56920m2 between Riohacha and Cabo de la Vela. The study was complemented with the evaluation of composition, abundance and size of gastropods conch found in the discarded-by-fishermen shell mounds in 13 beaches. In October 2010 another 40 transects were evaluated (16 000 m2) from the Southern of Riohacha to the Camarones village (La Guajira). We found a total of 9911 snails belonging to 12 species, the most abundant being Strombus pugilis with 8 912 individuals and an average density of 1 538.4 +/- 3 662.6 ind./ha, followed by Vasum muricatum with 374 individuals and an average density of 51.8 +/- 91.2 ind./ha. Calculating the importance value index (IVI) for both living organisms as the empty shells on beaches, shows that Turbinella angulata is the most used species by artisanal fishermen in the region. Cassis madagascariensis and Cassis tuberosa are also important snail resources in the region (as suggested by the number of empty shells found in beaches), but its densities were low. Strombus gigas, with only three living organisms found in the area, presented the lowest abundance ever found in the Colombian Caribbean (0.52 +/- 3.6 ind./ha), showing that queen conch population in La Guajira cannot support commercial exploitation. The abundance of discarded S. gigas shells on beaches suggests resource exploitation in the recent past. Results remarks the urgency of implementing management plans for snail fisheries in the region. PMID:23885583
Atmospheric Science Data Center
article title: Oil Slicks on Lake Maracaibo, Venezuela View Larger Image Several oil slicks occurred on Lake Maracaibo in northwestern Venezuela between ... wave facets divert reflected rays into many directions. An oil film dampens the presence of small wind-driven "capillary" waves, resulting ...
Solar Innovator | Alta Devices
Mattos, Laila; Le, Minh
Selected to participate in the Energy Department's SunShot Initiative, Alta Devices produces solar cells that convert sunlight into electricity at world record-breaking levels of efficiency. Through its innovative solar technology Alta is helping bring down the cost of solar. Learn more about the Energy Department's efforts to advance solar technology at energy.gov/solar .
Solar Innovator | Alta Devices
Mattos, Laila; Le, Minh
Selected to participate in the Energy Department's SunShot Initiative, Alta Devices produces solar cells that convert sunlight into electricity at world record-breaking levels of efficiency. Through its innovative solar technology Alta is helping bring down the cost of solar. Learn more about the Energy Department's efforts to advance solar technology at energy.gov/solar .
[Paleoclimate of La Guajira, Colombia; by the growth rings of Capparis odoratissima (Capparidaceae)].
Ramírez, Jorge Andrés; Ignacio del Valle, Jorge
There is great concern about the effect of climate change in arid and subarid areas of the tropics. Climate change combined with other anthropogenic activities such as deforestation, fires and over-grazing can accelerate their degradation and, consequently, the increases in losses of biological and economic productivity. Climate models, both local and global, predict that rainfall in the arid Peninsula of La Guajira in the Colombian Caribbean would be reduced and temperature would be increased as a result of climate change. However, as there are only suitable climate records since 1972, it is not possible to verify if, indeed, this is happening. To try to verify the hypothesis of reducing rainfall and rising temperatures we developed a growth ring chronology of Capparis odoratissima in the Middle Peninsula of La Guajira with 17 trees and 45 series which attain 48 years back. We use standard dendrochronological methods that showed statistically significant linear relationship with local climatic variables such as air temperature, sea surface temperature (SST), annual precipitation and wind speed; we also reach to successful relationship of the chronology with global climatic variables as the indices SOI and MEI of the ENSO phenomenon. The transfer functions estimated with the time series (1955 and 2003) do not showed statistically significant trends, indicating that during this period of time the annual precipitation or temperatures have not changed. The annual nature of C. odoratissima growth rings, the possibility of cross-dated among the samples of this species, and the high correlation with local and global climatic variables indicate a high potential of this species for dendrochronological studies in this part of the American continent. PMID:22017140
Picouet, M; Pellegrino, A; Papail, J
Immigration to Venezuela is examined using census data with the focus on the period 1971-1981. A brief overview of trends since the beginning of the twentieth century is first presented. The analysis indicates that "immigration to Venezuela is clearly of a short-term nature. Flows follow job opportunities and adjust to the labour market and to the financial capacity of the exchange market. The large increase of migratory movements to Venezuela in the 1970's is characterized by a diversification of their places of origin and by a greater instability. To a large extent, the migrants are illegal, especially those coming from Colombia and the Caribbean islands. Because of the crisis of the early 1980's, which is now worsened by the down trend of both oil prices and the U.S. dollar, Venezuela has become less attractive to immigrants, particularly from neighbouring countries." The authors observe that migrants in Venezuela are not well integrated and may depart, disrupting the labor supply in certain technical and specialized occupations (SUMMARY IN ENG AND SPA) PMID:12341015
Cenozoic transpressional model for the tectonic and basinal development of Venezuela and Trinidad
Pindell, J.L. ); Dewey, J.F. )
Geological features and plate tectonic constraints are integrated to outline a revised model for the Jurassic to Recent development of northern South America east of Guajira Peninsula. Development appears controlled by NoAm/SoAm and Carib/SoAm relative motions. Main phases were: (1) Jurassic rifting; (2) Late Jurassic - Maestrichtian passive margin sedimentation; (3) Eocene-Recent north-vergent understanding of Proto-Caribbean (Atlantic) crust beneath Venezuela; (4) eastwardly progressive Cenozoic south-vergent dextral transpression between northern South America and the Pacific-derived Caribbean Plate, and obduction of Caribbean terranes onto SoAm; (5) Neogene-Recent north-vergent underthrusting of Caribbean crust beneath the Guajira, Paraguana, and ABC (Aruba-Bonaire-Curacao-Orchila) terranes. Compressional and transcurrent sedimentary basins were developed in Cenozoic time in response to Carib-SoAm relative motion and terrane obduction, above rocks of the pre-existing Jurassic-Cretaceous passive shelf. Although Jurassic rift-related petroleum source rocks may have been deposited locally, primary source rocks are Upper Cretaceous and were deposited well after Jurassic rifting such that they were not affected by rift-related heat. In the absence of Cretaceous volcanism, geothermal gradients may be assumed to have been fairly normal. Maturation was thus a function of depth of burial, which was insufficient in each basin until Cenozoic basin development. A second phase of rapid deposition and hence maturation of Neogene age has occurred in inter-Andean basins of the west (e.g., Maracaibo) due to Miocene uplift and erosion of Andean ranges. These predicted maturation times are corroborated by more direct studies.
Anopheles species composition explains differences in Plasmodium transmission in La Guajira, northern Colombia
Herrera-Varela, Manuela; Orjuela, Lorena I; Peñalver, Cilia; Conn, Jan E; Quiñones, Martha L
Malaria in La Guajira, the most northern state of Colombia, shows two different epidemiological patterns. Malaria is endemic in the municipality of Dibulla whereas in Riohacha it is characterised by sporadic outbreaks. This study aimed to establish whether differences in transmission patterns could be attributed to different vector species. The most abundant adult female species were Anopheles aquasalis, exclusive to Riohacha, and Anopheles darlingi, restricted to Dibulla. Anopheles mosquitoes were identified using morphology and the molecular markers internal transcribed spacer 2 and cytochrome c oxidase I. All specimens (n = 1,393) were tested by ELISA to determine natural infection rates with Plasmodium falciparum and Plasmodium vivax. An. darlingi was positive for P. vivax 210, with an infection rate of 0.355% and an entomological inoculation rate of 15.87 infective bites/person/year. Anopheles albimanus larvae were the most common species in Riohacha, found in temporary swamps; in contrast, in Dibulla An. darlingi were detected mainly in permanent streams. Distinctive species composition and larval habitats in each municipality may explain the differences in Plasmodium transmission and suggest different local strategies should be used for vector control.
Venezuela`s gas industry poised for long term growth
Croft, G.D.
Venezuela`s enormous gas resource, combined with a new willingness to invite outside investment, could result in rapid growth in that industry into the next century. The development of liquefied natural gas exports will depend on the future course of gas prices in the US and Europe, but reserves are adequate to supply additional projects beyond the proposed Cristobal Colon project. Venezuela`s gas reserves are likely to increase if exploration for nonassociated gas is undertaken on a larger scale. The paper discusses gas reserves in Venezuela, internal gas markets, the potential for exports, competition from Trinidad, LNG export markets, and the encouragement of foreign investment in the gas industry of Venezuela.
First Record of Triatoma maculata (Erichson, 1848) (Hemiptera: Reduviidae: Triatomini) in the Municipality of Riohacha, La Guajira – Colombia
Gómez-Melendro, Edith Natalia; Hernández, Carolina; González-Uribe, Catalina; Brochero, Helena
Introduction: Knowledge of vector insect species, their habitat, and geographical distribution is crucial for determining the risk of transmission of the etiological agents that cause disease in humans, which allows defining strategies for prevention, surveillance, and control in line with the characteristics of each area. Objective: To determine the presence and public health importance of vectors of Chagas disease in the indigenous settlements of Marbacella and El Horno of the Wayúu ethnic group in the municipality of Riohacha, La Guajira, Colombia. Materials and Methods: From active search, installation and inspection of biosensors, and occasional catches, Hemiptera: Reduviidae: Triatomini were collected intra and in the peridomicile housing of the indigenous settlements of El Horno and Marbacella of the Wayúu ethnic group. Indices of intra and peridomestic infestation, colonization, density, dispersion, and natural infection with Trypanosoma cruzi Chagas, 1909 were calculated. Results: 79.6% (n = 90) of the specimens were collected in the peridomicile and 20.3% (n = 23) in the intradomicile, all corresponding to Triatoma maculata (Erichson, 1848). The natural infection indices with T. cruzi accounted for 43.5% for Marbacella and 36% for El Horno. Conclusion: This is the first reported capture of individuals of T. maculata, considered a secondary vector of Chagas disease in Colombia, naturally infected with T. cruzi in the municipality of Riohacha expanding the geographical distribution of the species in the department of La Guajira. PMID:25426481
NASA Astrophysics Data System (ADS)
Rosenzweig, Patricia
Since the installation of the Observatorio Cagigal in Caracas, astronomy in Venezuela has developed steadily, and, in the last few decades, has been strong. Both theoretical and observational astronomy now flourish in Venezuela. A research group, Grupo de Astrofísica (GA) at the Universidad de Los Andes (ULA) in Mérida, started with few members but now has increased its numbers and undergone many transformations, promoting the creation of the Grupo de Astrofísica Teórica (CAT), and with other collaborators initiated the creation of a graduate study program (that offers master's and doctor's degrees) in the Postgrado de Física Fundamental of ULA. With the financial support of domestic Science Foundations such as CONICIT, CDCHT, Fundacite, and individual and collective grants, many research projects have been started and many others are planned. Venezuelan astronomy has benefitted from the interest of researchers in other countries, who have helped to improve our scientific output and instrumentation. With the important collaboration of national and foreign institutions, astronomy is becoming one of the strongest disciplines of the next decade in Venezuela.
Koch, R
Since 1990, ACCSI has worked to safeguard the rights of people living with HIV/AIDS in Venezuela. The Pan American Health Organization (PAHO) had recognized ACCSI's program by 1992, enabling the nongovernmental organization (NGO) to establish fixed office hours during which it can receive clients. ACCSI does not distinguish between people living with HIV/AIDS and others, but considers it important to regulate AIDS as a public health issue within the context of human rights and ethics. Almost all of the Legal Office's initial cases were related to discrimination in the workplace, health centers, and educational institutions, but the ACCSI now also addresses family problems related to adoption, insurance, and inheritance, among others. To cope with the increase in service caseload, services have been extended through collaboration with specialized organizations concerned with human rights, women, children, prisons, and indigenous people. ACCSI influences governmental policy-making through its participation in the National AIDS Program. Moreover, ACCSI's networking activities ensure that the topic of HIV/AIDS and human rights is now always included in seminars and conferences in Venezuela, even when they are concerned with sexually transmitted diseases or other medical issues. Almost every time the press report upon AIDS, they consult the NGO. Everyday more people in Venezuela are standing up for their rights and denouncing discrimination against people infected with HIV. PMID:12347178
Enzootic Transmission of Yellow Fever Virus, Venezuela
Auguste, Albert J.; Lemey, Philippe; Bergren, Nicholas A.; Giambalvo, Dileyvic; Moncada, Maria; Morón, Dulce; Hernandez, Rosa; Navarro, Juan-Carlos
Phylogenetic analysis of yellow fever virus (YFV) strains isolated from Venezuela strongly supports YFV maintenance in situ in Venezuela, with evidence of regionally independent evolution within the country. However, there is considerable YFV movement from Brazil to Venezuela and between Trinidad and Venezuela. PMID:25531105
Potential for Great Thrust Earthquakes in NE Colombia & NW Venezuela
NASA Astrophysics Data System (ADS)
Bilham, R. G.; Mencin, D.
Sixty-five percent of the ≈19 mm/yr eastward velocity of the Caribbean Plate north of Aruba and the Guajira peninsula relative to the South American plate is accommodated by dextral slip on the Bocono Fault system in NW Venezuela at 12±1 mm/yr, the remaining ~3 mm/yr of shear apparently distributed to the NW of the fault (Perez et al., 2011). The N40E strike of the Bocono fault system, however, requires that 10.6±1 mm/yr of convergence should accompany this partitioned dextral shear, but GPS measurements reveal that less than 25% of this convergence occurs across the Venezuelan Andes. The remaining 6-8 mm of convergence is presumably accommodated by incipient subduction between the Bocono fault and a trench 300 km NW of the northern coast of Colombia. Hence NW Venezuela and NE Colombia may occasionally host great earthquakes. Our current poor understanding of the geometry of the plate interface permits the plate to be locked 300 km down-dip and possibly 600 km along-strike, and if the plate slips in 10 m ruptures it could do so every 1200 years in a M~9 earthquake. No great earthquake has occurred since 1492, since when ~4 m of potential slip has developed, but should slip occur on just 10% of the hypothesized décollement (100x150 km) it could do so now in an Mw=8.2 earthquake. In that a potential Mw>8 earthquake poses a future seismic and tsunami threat to the Caribbean it is important to examine whether great earthquakes have occurred previously near the NW Venezuela coast. It is possible that creep accommodates the entire convergence signal, since there is no suggestion from microseismicity for an abrupt locked-to-sliding transition, as, for example, signifies its location in the Himalaya. An alternative measure of future potential seismic energy release is to identify the locus and rate of present-day strain contraction. To this end, Venezuelan, Colombian and US (CU and UNAVCO) investigators are installing an array of more than a dozen continuous operating
Separation of the Guajira-Bonaire pair in the southern margin of the Caribbean: 65-50 Ma exhumation followed by 300 km right-lateral transtensional deformation
NASA Astrophysics Data System (ADS)
Zapata Henao, S.; Cardona, A.; Montes, C.; Valencia, V.; Vervoort, J. D.; Reiners, P. W.
Middle to upper Eocene fluvial strata in the island of Bonaire contains detrital components that were tracked to the basement massifs of the Guajira Peninsula in northern Colombia. These detrital components confirm previous hypothesis that the Guajira-Bonaire pair constitute a tectonic piercing point along the southern Caribbean plate margin that was right-laterally displaced approximately 300 km after middle Eocene times. Other possible sources, the nearby Curacao and the far away Santa Marta massif, did not pass statistical similarity and overlap tests. U-Pb LA-ICP-MS from the metamorphic boulders of the Soebi Blanco Formation in Bonaire yield Grenvillian ages (1084 Ma, 1130 Ma and 1184 Ma), while the detrital zircons recovered from the sandy matrix of the conglomerates contains populations with peaks of 1000 Ma - 1200 Ma, 750 Ma - 950 Ma, and 200 Ma - 300 Ma. Overlap and Similarity tests run between these populations and published data from Guajira yield values of 0.750 and 0.680, which are significantly higher than the same comparison against the Santa Marta Massif (0.637 and 0.522), and the Curacao island (0.629 and 0.467). Thermochronological results from the metamorphic clasts yield Paleocene-middle Eocene ages (65 - 50 Ma) that confirm not only a regional-scale cooling event in this time period, but also help constrain the maximum depositional age (50 Ma) of the poorly dated Soebi Blanco Formation. Figure 6. U-Pb results from analyzed samples and other Caribbean provinces. (A), Detrital zircons from Soebi Blanco conglomerate matrix; (B), Zircon ages from metamorphic clasts (C), detrital zircons from late Cretaceous Etpana Formation in Guajira Peninsula (Weber et al., 2010); (D), detrital zircons from late Cretaceous Santa Marta San Lorenzo schists (Cardona et al., 2010a); (E), detrital zircons from late Cretaceous Knip Group (Wrigth and Wyld, 2010); (F), overlap and similarity values.
Apheresis activity in Venezuela.
Saltiel, Christiane
Interest for apheresis activity has been growing in Venezuela. In 1976 there were only a few devices; in 2003, 80 apheresis machines performed 27,675 donor apheresis procedures and 547 therapeutic procedures countrywide. We report the activity at the Metropolitan Blood Bank (the largest one of the country) in the period 1999-2003: 597 therapeutic procedures were performed in 171 patients, during 212 crisis episodes. The average age was 38 +/- 16 years, 65% male and 35% female. Most of the therapeutic procedures were therapeutic plasma exchange for hematology diseases (mainly thrombotic thrombocitopenic purpura and hemophilia inhibitors), including 184 therapeutic procedures with the Autopheresis-C (Baxter Healthcare Corp., Deerfield, IL). Most common adverse effects (3.9%) were hypotension and allergic reactions to the plasma. PMID:15880361
Mosquera, B
The lack of knowledge and awareness about HIV in Venezuela is causing anxiety. Most Venezuelans still believe that AIDS is a disease that only homosexuals get and others believe that it is a punishment from God. To take control of the situation, adolescents need to be given prevention education, and the government needs to stop the false rumors. The Latin American AIDS Koalition (LAAK) and Venezuelans in the United States are working on providing education to the public and medications to people living with HIV/AIDS in Venezuela. Telephone numbers are provided for more information. PMID:11364949
Venezuela. America = Las Americas [Series].
ERIC Educational Resources Information Center
Toro, Leonor; Avery, Robert S.
This bilingual English/Spanish social studies resource booklet provides an encyclopedia-style overview of Venezuela's history, geography, economy, and culture for teachers to use with migrant children in the elementary grades. Topics presented in the English portion include climate, land, people, customs, government, arts, food, culture, wildlife,…
Code of Federal Regulations, 2012 CFR
..., photorevised 1979, minor revision 1993. (c) Boundary. The Alta Mesa viticultural area is located in Sacramento County, California, and is entirely within the Lodi viticultural area (27 CFR 9.107). The Alta...
Hydrocarbon potential of Central Monagas, Eastern Venezuela Basin, Venezuela
Barrios, F.; Daza, J.; Iusco, G.
The Central Monagas area is part of the foreland sub-basin located on the southern flank of the Eastern Venezuela Basin. The sedimentary column of the Central Monagas is at least 7500 in thick and consists of Mesozoic (Cretaceous) and Cenozoic rocks. Interpretations of 60 regional seismic sections have been integrated with data from 12 existing wells, which cover an area of 1200 km{sup 2}. From these interpretations, basin-wide structure and interval isopach maps were constructed in order to aid the depiction of the basin architecture and tectonic history. The sub-basin developed on the southern flank of the Eastern Venezuela Basin is tightly linked to its evolution from a Mesozoic extensional regime into a Cenozoic compressional and strike-slip stage. The basin formed in the Middle Mesozoic by crustal extension of a rifting process. Regional northward tilting of the slab continued during the Late Cretaceous. Finally, the transpression of the Caribbean Plate during the Oligocene-Neogene induced the overprint of compressional deformation associated with the deposition of a foredeep wedge. Geochemical source rock analysis gave an average of 1.2 TOC, and R{sub o} of 0.66 indicating a mature, marine source. The modeling of the hydrocarbon generative history of the basin indicates that the oil migration started in the Middle Miocene, after the trap was formed. Analysis and mapping of reservoir rocks and seal rocks defined the effective area limits of these critical factors. The main play in the area is the extension of the Lower Oficina Formation which is the proven petroleum target in the Eastern Venezuela Basin.
Republic of Venezuela. Country profile.
Hakkert, R
Venezuela's current economic and demographic situation is described. Venezuela is a major oil country, and the oil industry accounts for 90% of the country's foreign exchange, 70% of the government's revenues, and 15% of the gross domestic product. The economy experienced a sudden and high rate of economic growth in the mid-1970s as a result of high oil prices; however, in recent years, declining oil prices have had a negative effect on the economy. The country is now faced with a serious trade deficit, and the government recently imposed restrictions on imports. Imports in recently years had increased markedly. The emphasis on the oil industry weakened the agricultural sector and, as a result, food imports increased. In addition, the rapid economic growth experienced during the 1970s greatly increased the demand for imported consumer goods. Venezuela has the 4th highest foreign debt in the world (US$35 billion). Despite these problems Venezuela has a relatively high per capita income (US$4,140) and living standard, compared to other countries in the region. Venezuela's total population is 14.6 million, and the population is unevenly distributed. 86% of the population lives in cities of 2500 or more. 37.4% of the population and 70% of the industry is concentrated in the Federal District which contains Caracas, and in the surrounding states of Aragua, Miranda, and Carabobo. This area constitutes only 2.36% of the country's territory. Most of the oil fields are located in the state of Zulia which also contains the country's 2nd largest city (Maracaibo). The country's coastal area contains most of the agricultural lands, and the prairies just south of the coastal mountain ranges are devoted primarily to cattle raising. The remaining 58.2% of the country's territory is essentially jungle and contains only 6.9% of the country's population. The annual population growth rate is 3.11%. Although the rate declined in recent years it is higher than in most of the other
An Example of Educational Transformation: Venezuela.
ERIC Educational Resources Information Center
Cirigliano, Gustavo F. J.
Presents a case study of educational development in Venezuela, with emphasis on political and cultural influences, social needs, needs of developing nations, experimentation on all levels, fellowship programs, and projections for the future. (DB)
Reformulated gasoline deal with Venezuela draws heat
Begley, R.
A fight is brewing in Congress over a deal to let Venezuela off the hook in complying with the Clean Air Act reformulated gasoline rule. When Venezuela threatened to call for a GATT panel to challenge the rule as a trade barrier, the Clinton Administration negotiated to alter the rule, a deal that members of Congress are characterizing as {open_quotes}secret{close_quotes} and {open_quotes}back door.{close_quotes}
An Energy Overview of Venezuela
The DOE Office of Fossil Energy is maintaining a web site that is meant to provide useful business- and energy-related information about countries and regions of the world for exporters, project developers, and researchers. The site consists of more than 130 country pages (organized into seven different world regions), with each country page having its own set of links to information sources about that country. There are also more than 30 Country Energy Overviews at the web site -- each of these is a comprehensive review of a specific country's entire energy situation, including sections on Energy Policy, Oil, Natural Gas, Coal, Hydroelectric/Renewables, Nuclear Power, Energy Transmission Infrastructure, Electricity, Electric Industry Overview, Environmental Activities, Privatization, Trade, and Economic Situation. The specific country highlighted in this Country Energy Overview is Venezuela. The site is designed to be dynamic. Updates to the overviews will be made as need and resources permit.
Code of Federal Regulations, 2010 CFR
... County, California, and is entirely within the Lodi viticultural area (27 CFR 9.107). The Alta Mesa... Grant Line Road to Wilton Road at the hamlet of Sheldon, and then continue southeast on Wilton Road...
Ceuta-Tomoporo field, Venezuela
Puig, E.R.; Fernando Marcano, R. )
Ceuta field is located in the southeastern part of the Maracaibo basin, western Venezuela. The field is a conspicuous high belonging to the Pueblo Viejo trend, a set of strike-slip faults trending northwest. The field has an area of 320 km and is divided into eight fault-bounded blocks where light- or medium-grade oil is being produced. The structural framework is characterized by a major left-slip fault and oil accumulations are associated with compressive and extensive structural features. The deposition of Eocene sediments in some areas may have been controlled by normal faulting and a period of shortening may have altered the character of some of the faults during the late Eocene or later. The main producing intervals are shallow-water marine or fluviodeltaic Miocene and Eocene sands with porosities ranging from 8 to 15% and a production potential of up to 3,500 BOPD from depths averaging 5,182 m (17,000 ft). The reservoirs seem to contain mixtures of hydrocarbons, probably due to the generation of oil in more than one oil kitchen and/or at different migration times from a common drainage area.
Petroleum systems of western Venezuela
Passalacqua, H.; Gallango, O.; Capello, M.A.; deToni, B.; Tocco, R.; Truskowski, I.; Loureiro, D.
Integrating multidisciplinary information from western Venezuela Intevep, S.A. developed a comprehensive geological synthesis of the Maracaibo, Barinas and Apure basins which allow the description of 5 petroliferous systems with pods located within the Venezuelan borders: (1) Northeast of Maracaibo Basin, (2) Southwest of Maracaibo Basin, (3) Eastern Zulia, (4) Lara`s Nappes and (5) Barinas Subbasin. These systems comprise different structural styles: (1) basement tectonics, (2) thin-skin tectonics, (3) inversions, (4) triangular zones, (5) {open_quotes}flower and pop-up{close_quotes} structures. The main reservoirs in the region are the fractured Cretaceous limestones (K0 to K5), the Lower to Middle Eocene sandstones (T1 Misoa C and Misoa BC) and the Miocene sandstones of the Lagunillas Formation. Three source rocks were identified: the principal one of Cretaceous age, marine origin and totally located in the Maracaibo Basin (K3-K4-K5, La Luna and Capacho formations) and two located south and southwest of the Maracaibo Basin, with organic material of continental origin, of Paleocene (K7-K8, Orocue and Marcelina formations) and Oligocene age (T4, Carbonera Formation). Three expulsion periods were encountered: (a) Lower to Middle Eocene (52-40 Ma) and (b) Upper Eocene to Lower Miocene (40-21 Ma), with pods located in the northeast region of the Maracaibo Lake and (c) Lower Miocene to Holocene (2 1-0 Ma) with a pod located in the Maracaibo Lake.
Identifying barriers to move to better health coverage: preferences for health insurance benefits among the rural poor population in La Guajira, Colombia.
Amaya, Jeannette Liliana; Ruiz, Fernando; Trujillo, Antonio J; Buttorff, Christine
Even though access to health insurance in Colombia has improved since the implementation of the 1993 health reforms (Law 100), universal coverage has not yet been accomplished. There is still a segment of the population under the low-income (subsidized) health insurance policy or without health insurance altogether. The purpose of this research was to identify preferences and behavior regarding health insurance among the subsidized rural population in La Guajira, Colombia, and to understand why that population remains under the subsidized health insurance policy. The field experiment gathered information from 400 households regarding their socioeconomic situation, health conditions, and preferences for health insurance characteristics. Results suggest that the surveyed population gives priority to expanded family coverage, physician and hospital choice, and access to specialists, rather than to attributes associated with co-payments or premiums. That indicates that people value healthcare benefits and family coverage more than health insurance expenses, and policy makers could use these preferences to enroll subsidized population into the contributory regime. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25111823
The Development of Education in Venezuela.
ERIC Educational Resources Information Center
Sanchez, George I.
The present study aims to bring to the reader an understanding of Venezuela's educational patterns, needs, and development within the framework of the country's economic and social situation. Much of this report is devoted to historical backgrounds --to cultural development, politics, immigration, economics, and international attitudes-- to give…
Implementing Pre-Vocational Studies in Venezuela.
ERIC Educational Resources Information Center
Kim, Young Mi
This paper describes prevocational education in Venezuela on each educational level. First, it sets a historical context by identifying aspects of technical education that emerged at different times in its development; then it identifies certain strategies created to support the implementation of prevocationalization, and finally it concludes by…
The history of aeronautical medicine in Venezuela
NASA Technical Reports Server (NTRS)
Iriarte, D. R.
The Aerial Medical Service of the Ministry of Transportation and Communications of Venezuela was created on June 1949, and later became the Department of Aeronautical Medicine. Its functions include the medical examinations of future pilots, navigators and flight engineers. The importance of good mental and physical health in all flight and ground personnel to ensure the safety of air travel is discussed.
Mastery: A Lesson from Maria in Venezuela
ERIC Educational Resources Information Center
Powell, Sandra Anez; Powell, Norman W.
Children who have been born into poverty or into at-risk circumstances are often considered "disposable" and not a societal priority. These youngsters have few advocates and limited successful options in life. In the city of Maracaibo, Venezuela, there is a large population of Amerindians who are called Guajiros. These indigenous people have…
Venezuela natural gas for vehicles project
Marsicobetre, D.; Molero, T.
The Natural Gas for Vehicles (NGV) Project in Venezuela describes the development and growth of the NGV project in the country. Venezuela is a prolific oil producer with advanced exploration, production, refining and solid marketing infrastructure. Gas production is 5.2 Bscfd. The Venezuelan Government and the oil state owned company Petroleos de Venezuela (PDVSA), pursued the opportunity of using natural gas for vehicles based on the huge amounts of gas reserves present and produced every day associated with the oil production. A nationwide gas pipeline network crosses the country from south to west reaching the most important cities and serving domestic and industrial purposes but there are no facilities to process or export liquefied natural gas. NGV has been introduced gradually in Venezuela over the last eight years by PDVSA. One hundred forty-five NGV stations have been installed and another 25 are under construction. Work done comprises displacement or relocation of existing gasoline equipment, civil work, installation and commissioning of equipment. The acceptance and usage of the NGV system is reflected in the more than 17,000 vehicles that have been converted to date using the equivalent of 2,000 bbl oil/day.
Code of Federal Regulations, 2014 CFR
... County, California, and is entirely within the Lodi viticultural area (27 CFR 9.107). The Alta Mesa... line's intersection with the 105-foot contour line and an unimproved extension of Blake Road, section 9, T6N, R7E (Sloughhouse Quadrangle); then (9) Proceed west 0.3 mile on the unimproved extension of...
Code of Federal Regulations, 2013 CFR
... County, California, and is entirely within the Lodi viticultural area (27 CFR 9.107). The Alta Mesa... line's intersection with the 105-foot contour line and an unimproved extension of Blake Road, section 9, T6N, R7E (Sloughhouse Quadrangle); then (9) Proceed west 0.3 mile on the unimproved extension of...
Code of Federal Regulations, 2011 CFR
... County, California, and is entirely within the Lodi viticultural area (27 CFR 9.107). The Alta Mesa... line's intersection with the 105-foot contour line and an unimproved extension of Blake Road, section 9, T6N, R7E (Sloughhouse Quadrangle); then (9) Proceed west 0.3 mile on the unimproved extension of...
Plans to revive oil fields in Venezuela on track
Not Available
This paper reports on the three operating units of Venezuela's state owned oil company Petroleos de Venezuela SA which will begin receiving bids Feb. 28 from companies interested in operating 55 inactive oil fields in nine producing areas of Venezuela. Francisco Pradas, Pdvsa executive in charge of the program, the the company expects 88 companies or combines of foreign and domestic private companies to participate in the bidding. The program, announced last year, aims to reactivate production in marginal oil fields. It will involve the first direct participation by private companies in Venezuela's oil production since nationalization in 1976.
Astrometry and Geostationary Satellites in Venezuela
NASA Astrophysics Data System (ADS)
Lacruz, E.; Abad, C.
We present the current status and the first results of the astrometric project CIDA - ABAE for tracking geo-stationary satellites. This project aims to determine a preliminary orbit for the Venezuelan satellite VENESAT-1, using astrometric positions obtained from an optical telescope. The results presented here are based on observations from the Luepa space tracking ground station in Venezuela, which were processed using astrometric procedures.
The Dairy Technology System in Venezuela. Summary of Research 79.
ERIC Educational Resources Information Center
Nieto, Ruben D.; Henderson, Janet L.
A study examined the agricultural technology system in Venezuela with emphasis on the dairy industry. An analytical framework was used to identify the strengths and weaknesses of the following components of Venezuela's agricultural technology system: policy, technology development, technology transfer, and technology use. Selected government…
Language Planning for Venezuela: The Role of English.
ERIC Educational Resources Information Center
Kelsey, Irving; Serrano, Jose
A rationale for teaching foreign languages in Venezuelan schools is discussed. An included sociolinguistic profile of Venezuela indicates that Spanish is the sole language of internal communication needs. Other languages spoken in Venezuela serve primarily a group function among the immigrant and indigenous communities. However, the teaching of…
Critical Pedagogy and Empowering in Teacher Education in Venezuela.
ERIC Educational Resources Information Center
Chacon, Carmen T.; Alvarez, Luisa Cristina
This paper addresses the issue of the relationship between critical pedagogy and English as a foreign language (EFL) in Venezuela. Teacher-researchers have come to see the issues confronting nonnative educators in ELT as a more important issue than in previous years. They are particularly concerned about the current situation in Venezuela,…
Using the Five Themes of Geography to Teach about Venezuela.
ERIC Educational Resources Information Center
Sunal, Cynthia Szymanski; And Others
Maintains that Venezuela has many U.S. ties because of its relative proximity and economic significance. Asserts that the Five Themes of Geography can be used to design effective classroom lessons about Venezuela. Presents five activities that include student objectives, necessary materials, and step-by-step instructional procedures. (CFR)
78 FR 55096 - Ferrosilicon from Russia and Venezuela
Federal Register 2010, 2011, 2012, 2013, 2014
... publishing the notice in the Federal Register of July 25, 2013 (78 FR 44969). The conference was held in... COMMISSION Ferrosilicon from Russia and Venezuela Determination On the basis of the record \\1\\ developed in... Russia and Venezuela of ferrosilicon, provided for in subheadings 7202.21.10, 7202.21.50,...
Occurrence of methylmercury in Lake Valencia, Venezuela
Jaffe, R.; Cai, Y.; West-Thomas, J.
The presence of mercury in the environment has received renewed attention during recent years. This is in part due to the known human health and ecological effects of the highly toxic organomercury compounds, and to the fact that novel and improved analytical techniques such as atomic fluorescence spectroscopy (AFS) and capillary chromatography with AFS detection, have enhanced significantly the detection of trace amounts of mercury and organo mercurials in environmental samples. Such techniques have allowed for a better understanding of the biogeochemical cycle of mercury in the aquatic environment. This paper reports on the presence of methylmercury in the water column and sediments of a hyper-eutrophic lake. Lake Valencia is a freshwater lake located in North-Central Venezuela`s Aragua Valley. The lake`s surface area covers approximately 350 km{sup 2}, with a mean depth of 19 m and a maximum depth of 41 m. Due to the discharge of waste waters from the cities of Maracay and Valencia, as well as from other smaller villages and agricultural areas in its watershed, Lake Valencia has become hyper-eutrophic. The population of phytoplankton, particularly of blue-green algae, has increased dramatically during the last two decades resulting in anoxic conditions in the lower part of the water column during most of the year. In addition, concentrations of anthropogenic chemicals, including heavy metals, have increased in the Lake during the last four decades. 15 refs., 2 figs.
[Zika virus: Another emerging arbovirus in Venezuela?].
Valero Nereida
Current health conditions of Venezuela, together with the tropical proliferation of different types of Aedes (aegypti and albopictus), suggest the arrival to this country of ZIKA virus (ZIKV). The Pan American Health Organization urges Latin American countries to take measures to prevent the ZIKV entry and advises that these measures must be designed to detect the introduction of ZIKV in an area, track its spread and actively monitor the disease. In Venezuela and other Latin-American countries, where endemicity is high for other arboviruses such as dengue arid chikungunya, health authorities should strengthen their surveillance systems to detect early and timely introduction of ZIKV ap.d refine diagnostic methods to confirm the infection rate; however, the high incidence of cases due those viral agents reflects weakened and poorly timed insensitive monitoring systems, as well as, poor vector control measures, arising the questions: will this arbovirus pop in our country, will it set as the other as edemicepidemic and lead to alter their clinical behavior and severity of the disease? PMID:26710538
View of the Caribbean coast of Venezuela
NASA Technical Reports Server (NTRS)
A near vertical view of the Caribbean coast of Venezuela is seen in this Skylab 3 Earth Resources Experiment Package S190-B (five-inch earth terrain camera) photograph taken from the Skylab space station in Earth orbit. The large body of water is the Golfo de Venezuela; and the major land mass is the Peninsula de Paraguana. The view is looking northward from the mouth of the Golfete de Coro and Punta Cardon to Punta Macolia. The peninsula is connected to the Venezuelan mainland by the narrow strip of land in the most easterly corner of the picture. The dry, arid climate of the peninsula is indicated by sparse vegetation and the abundance of sand dunes. The highest point is about 2,700 feet above the sea and is the conspicuous black spot. Old raised shorelines features appear as streaks parallel to the Golfete de Coro. Water of the Golfete de Coro is red from the high sediment content. The streaks in the water off the peninsula is apparently an effect of wind which is blowing sand and w
World Wide Web Search Engines: AltaVista and Yahoo.
ERIC Educational Resources Information Center
Machovec, George S., Ed.
Examines the history, structure, and search capabilities of Internet search tools AltaVista and Yahoo. AltaVista provides relevance-ranked feedback on full-text searches. Yahoo indexes Web "citations" only but does organize information hierarchically into predefined categories. Yahoo has recently become a publicly held company and currently…
Hydrogen: BOC-FW venture secures major Venezuela project
Wood, A.
BOC Gases and Foster Wheeler Power Systems (FW) have been awarded a $50-million project to supply a 50-million cu ft/day hydrogen (H{sub 2}) plant to Lagoven`s Amuay, Venezuela refinery for 1997 startup. BOC and FW have also formed a marketing agreement for on-site H{sub 2} plants in the Americas, extending a previous relationship covering Chile and Venezuela.
[Historical overview of antimalarials used in Venezuela].
Zerpa de Artiles, N
A historical review of antimalarials used in Venezuela is presented from the time when the bark of quina was used until the massive distribution of quinine and metoquine by the Dirección de Malariología y Saneamiento Ambiental. The utility of chloroquine and primaquine against sensible parasite isolates and of sulfadoxine-pyrimethamine and quinine, currently used against P. falciparum resistant strains, is thoroughly discussed. The author suggests use of artemisimine and its derivatives as a very promising antimalarial drug. She also stresses the possibility of the application of new antimalaria vaccine against P. falciparum blood states, presently assayed in the country as an additional tool in malaria control programs. PMID:11640680
Digital shaded-relief map of Venezuela
Garrity, Christopher P.; Hackley, Paul C.; Urbani, Franco
The Digital Shaded-Relief Map of Venezuela is a composite of more than 20 tiles of 90 meter (3 arc second) pixel resolution elevation data, captured during the Shuttle Radar Topography Mission (SRTM) in February 2000. The SRTM, a joint project between the National Geospatial-Intelligence Agency (NGA) and the National Aeronautics and Space Administration (NASA), provides the most accurate and comprehensive international digital elevation dataset ever assembled. The 10-day flight mission aboard the U.S. Space Shuttle Endeavour obtained elevation data for about 80% of the world's landmass at 3-5 meter pixel resolution through the use of synthetic aperture radar (SAR) technology. SAR is desirable because it acquires data along continuous swaths, maintaining data consistency across large areas, independent of cloud cover. Swaths were captured at an altitude of 230 km, and are approximately 225 km wide with varying lengths. Rendering of the shaded-relief image required editing of the raw elevation data to remove numerous holes and anomalously high and low values inherent in the dataset. Customized ArcInfo Arc Macro Language (AML) scripts were written to interpolate areas of null values and generalize irregular elevation spikes and wells. Coastlines and major water bodies used as a clipping mask were extracted from 1:500,000-scale geologic maps of Venezuela (Bellizzia and others, 1976). The shaded-relief image was rendered with an illumination azimuth of 315? and an altitude of 65?. A vertical exaggeration of 2X was applied to the image to enhance land-surface features. Image post-processing techniques were accomplished using conventional desktop imaging software.
David Meets Goliath on the Information Superhighway: Venezuela in the Context of the Electronic Communication Networks.
ERIC Educational Resources Information Center
Sanchez-Vegas, Saadia
Discusses Venezuela's information and communications technology infrastructure and usage patterns; examines future networking plans; and addresses political and economic considerations linked to the information and technology problems in Venezuela and in Latin America in general. (LRW)
An Interview with Margot Benacerraf: Reveron, Araya, and the Institutionalization of Cinema in Venezuela.
ERIC Educational Resources Information Center
Schwartzman, Karen
Presents an interview (edited into a first-person form) with Margot Benacerraf, known for two prize-winning films in the 1950s but not as well known for her active promotion of film culture in Venezuela. Discusses her education in Venezuela, travels outside Venezuela, production of her prize-winning films, and her efforts at promoting the…
Malaria control and elimination, Venezuela, 1800s –1970s.
Griffing, Sean M; Villegas, Leopoldo; Udhayakumar, Venkatachalam
Venezuela had the highest number of human malaria cases in Latin American before 1936. During 1891–1920,malaria was endemic to >600,000 km2 of this country; malaria death rates led to major population decreases during 1891–1920. No pathogen, including the influenza virus that caused the 1918 pandemic, caused more deaths than malaria during 1905–1945. Early reports of malaria eradication in Venezuela helped spark the world's interest in global eradication. We describe early approaches to malaria epidemiology in Venezuela and how this country developed an efficient control program and an approach to eradication.Arnoldo Gabaldón was a key policy maker during this development process. He directed malaria control in Venezuela from the late 1930s to the end of the 1970s and contributed to malaria program planning of the World Health Organization.We discuss how his efforts helped reduce the incidence of malaria in Venezuela and how his approach diverged from World Health Organization guidelines. PMID:25396258
Malaria Control and Elimination,1 Venezuela, 1800s–1970s
Villegas, Leopoldo; Udhayakumar, Venkatachalam
Venezuela had the highest number of human malaria cases in Latin American before 1936. During 1891–1920, malaria was endemic to >600,000 km2 of this country; malaria death rates led to major population decreases during 1891–1920. No pathogen, including the influenza virus that caused the 1918 pandemic, caused more deaths than malaria during 1905–1945. Early reports of malaria eradication in Venezuela helped spark the world's interest in global eradication. We describe early approaches to malaria epidemiology in Venezuela and how this country developed an efficient control program and an approach to eradication. Arnoldo Gabaldón was a key policy maker during this development process. He directed malaria control in Venezuela from the late 1930s to the end of the 1970s and contributed to malaria program planning of the World Health Organization. We discuss how his efforts helped reduce the incidence of malaria in Venezuela and how his approach diverged from World Health Organization guidelines.
The Alta schist, North Norway: unique rock with unique history
NASA Astrophysics Data System (ADS)
Heldal, Tom; Aasly, Kari; Meyer, Gurli
Near the small town of Alta, northernmost Norway, are more than thousand small and large schist quarries, some of them dating back to the 1850's. It was the need for roofing material on a local church and a hospital that triggered the production. Since then, the Alta schist has been widely applied in Norway and abroad, known for its quality for roofing material and hard floor covering. The quality lies in the processes behind the formation of the schist. Emplacement of thrust nappes during the Caledonian mountain chain formation in the Silurian caused deformation and metamorphism of the rocks. The Alta schist is situated in one such nappe sheet, where arkosic sandstone where flattened and transformed into mylonite. This made fine mica layers along which the rock can be split, rythmically spaced and separated by quartz-dominated bands. The production of the Alta schist is still characterized by old craft traditions, reflecting a rich history and culture around the schist production.
[Increasing difficulties for scientific publication in Venezuela].
Ryder, Elena
A very important increase in the costs of the edition of scientific journals has taken place in Venezuela, due to difficulties in obtaining imported free acid paper and other materials used for handling documents. Like other journals, Investigaci6n Clinica has been considering switching completely to a digital publication format; however there are several reasons that prevent us to doing it at this time: the journal is distributed in printed form to many national institutions, which do not have immediate access to digital information. In addition, there exists a commitment of shipment of printed issues for some international indices and in exchange with other national and foreign journals, whose printed format we receive. Another important aspect is that our University maintains a weak technological platform that makes difficult the immediacy required for the interchange with authors and consulted referees of received papers; and there is a latent danger of limitations in the use of digital technologies, due to current national politic problems. Consequently, we need to continue with the printed format, but must reduce the amount of printed issues, so as not to limit the number of papers published in each edition. Nevertheless, there is an ever increasing number of contributions from foreign researches and Investigaci6n Clinica has been recently included in two new international indices, the SEIIC from Argentina and the Infobase Index from India, reasons that obligate us to maintain our levels of excellence and commitment to our authors and readers. PMID:24758096
Composition and Ultrastructure of Streptomyces venezuelae
Bradley, S. G.; Ritzi, Donna
Streptomyces venezuelae is a filamentous bacterium with branching vegetative hyphae embedded in the substrate and aerial hyphae bearing spores. The exterior of the spore is inlaid with myriads of tiny rods which can be removed with xylene. The spore wall is approximately 30 nanometers thick. Occasionally, it can be seen that the plasma membrane and the membranous bodies within a spore are connected. The spore's germ plasm is not separated from the cytoplasm by a nuclear envelope. The cell walls of the vegetative hyphae, which are about 15 nanometers thick, are structurally and chemically similar to those of gram-positive bacteria. The numerous internal membranous bodies, some of which arise from the plasma membrane of the vegetative hypha, may be vesicular, whirled, or convoluted. Membranous bodies are usually prominent at the hyphal apices and are associated with septum formation. The germ plasm is an elongate, contorted, centrally placed area of lower electron density than the hyphal cytoplasm. The spores differ from the vegetative hyphae, not only in fine structure, but also in the arginine and leucine contents of their total cellular proteins. Images PMID:5669907
Malaria entomological inoculation rates in western Venezuela.
Rubio-Palis, Y; Wirtz, R A; Curtis, C F
Over 61,000 anophelines collected between January 1988 and October 1989 in three villages in western Venezuela were assayed by ELISA for Plasmodium vivax circumsporozoite (CS) protein. The six specimens confirmed positive belonged to three species: Anopheles (Nyssorhynchus) nuneztovari Gabaldón, 1940, A. albitarsis Arribalzaga, 1878 sensu lato and A. oswaldoi (Peryassu, 1922). The estimated CS protein rate for all species combined was 0.01% (95% confidence limits 0.004-0.02%). This CS protein rate and the mean number of bites received by the collectors indicated a sporozoite inoculation rate of about 10.5 infective bites per person per year. From this value and the number of human malaria cases reported it was estimated that only 0.32% of bites by CS-positive mosquitoes led to a malaria infection. The CS protein rate is so low that this parameter would not be a practical indicator of the efficacy of control campaigns in this area. PMID:1363181
Syllidae (Annelida, Polychaeta) from the Caribbean coast of Venezuela
Liñero-Arana, Ildefonso; Díaz Díaz, Oscarn
Abstract Venezuela possesses a great variety of coastal environments allowing for a high diversity of marine species. However, systematic studies on marine invertebrates are scarce, especially on polychaetes. The family Syllidae is poorly known, and only 14 genera and 42 species have been reported from this country. A total of 13 genera and 26 species the Syllidae were identified from benthic samples collected on different substrata of the northeastern coast of Venezuela. Of these, seven genera and 16 species constitute new records for Venezuela: Odontosyllis guillermoi, Syllides floridanus, Salvatoria clavata, Salvatoria limbata, Sphaerosyllis longicauda, Parapionosyllis longicirrata, Trypanosyllis parvidentata, Trypanosyllis vittigera, Opisthosyllis sp., Syllis amica, Syllis armillaris, Syllis gracilis, Syllis pseudoarmillaris, Syllis vittata, Parasphaerosyllis indica and Myrianida convoluta. PMID:21998503
Current Space Projects of the Bolivarian Republic of Venezuela
NASA Astrophysics Data System (ADS)
Hernández, R.; Acevedo R.; Varela, F.; Otero, S.
Since 2008, with the successful launch of the first Venezuelan telecommunication satellite VENESAT-1, the Bolivarian Republic of Venezuela became an active player in the international space sector aimed at using space science and technology as a powerful tool to promote the national development. Based on that, through the Bolivarian Agency for Space Activities (ABAE), Venezuela has been implemented several space projects such as the manufacturing and launch of the first Venezuelan remote sensing satellite, the construction of a design center for small satellite technologies, as well as research and development activities related with the estimation of the physical properties of the Earth. This paper presents a brief description of the current space projects that are being developed by Venezuela.
Digital geologic map and GIS database of Venezuela
Garrity, Christopher P.; Hackley, Paul C.; Urbani, Franco
The digital geologic map and GIS database of Venezuela captures GIS compatible geologic and hydrologic data from the 'Geologic Shaded Relief Map of Venezuela,' which was released online as U.S. Geological Survey Open-File Report 2005-1038. Digital datasets and corresponding metadata files are stored in ESRI geodatabase format; accessible via ArcGIS 9.X. Feature classes in the geodatabase include geologic unit polygons, open water polygons, coincident geologic unit linework (contacts, faults, etc.) and non-coincident geologic unit linework (folds, drainage networks, etc.). Geologic unit polygon data were attributed for age, name, and lithologic type following the Lexico Estratigrafico de Venezuela. All digital datasets were captured from source data at 1:750,000. Although users may view and analyze data at varying scales, the authors make no guarantee as to the accuracy of the data at scales larger than 1:750,000.
Events affecting gold exploration in Venezuela since 1999
Wilburn, David R.
The structure of the gold mining industry in Venezuela has changed significantly since 1999 as a result of Government policy changes and industry response to these changes. This report documents the policy decisions that have affected the mining industry, discusses the response of the industry on a site by site basis, and suggests possible effects of these changes on the global economy. For the short term, at least, it appears that these changes have made Venezuela a more difficult place to invest for U.S. and Canadian companies, while investment by Chinese entities has been encouraged.
Wing shape divergence between Rhodnius prolixus from Cojedes (Venezuela) and Rhodnius robustus from Mérida (Venezuela).
Villegas, J; Feliciangeli, M D; Dujardin, J P
The existence of Rhodnius robustus as a species distinct from Rhodnius prolixus has long been the main epidemiological question about Chagas disease transmission in Venezuela and surrounding countries. These two taxa are morphologically and genetically very similar, but only R. prolixus is assumed to colonize houses and transmit Chagas disease to humans. R. robustus is assumed to be an exclusively sylvatic species, restricted to palm trees. If robustus and prolixus are actually the same species, the theoretical possibility exists of sylvatic specimens invading houses, even after insecticide application, and a control strategy similar to that of the successful Southern Cone Initiative against Triatoma infestans would be difficult to consider. Since no valid alternative control strategy exists, the answer to this biological question could be decisive about the future of vector control in this region. Although we believe genetic techniques are best suited to define species boundaries, we present here an example of the relevance of modern morphometrics in dealing with such an issue. Using both traditional and geometric morphometrics, we compared the wing size and shape in both sexes of these two taxa reared in the same laboratory for one generation. R. robustus specimens were collected from palm trees in the state of Mérida (Venezuela), and R. prolixus were collected from houses in the state of Cojedes (Venezuela). Our study provided no argument to question their specific status. Even after one generation of living in the same laboratory conditions, the two lines showed clear size differences, divergent allometric trends, and significant allometry-free differences in shape. These results suggest that R. robustus (Mérida, Venezuela) and R. prolixus (Cojedes, Venezuela) are distinct evolutionary units. Due to the epidemiological importance of this question, further studies in other geographic areas of Venezuela are required to accurately define the relationships of R
The Bocono Fault Zone, Western Venezuela
Schubert, C. ); Estevez, R. ); Henneberg, H.G. )
The Bocono Fault Zone, the western part of the Bocono Moron-El Pilar Fault System of the southern Caribbean plate boundary, consists of aligned valleys, linear depressions, pull-apart basins and other morphological features, which extend for about 500 km in a N45[degrees]E direction, between the Tachira depression (Venezuela-Colombia border) and the Caribbean Sea. It crosses obliquely the Cordillera de Merida and cuts across the Caribbean Mountains, two different geologic provinces of Late Tertiary-Quaternary and Late Cretaceous-Early Tertiary age, respectively. Therefore, the maximum age that can be assigned to the Bocono Fault Zone is Late Tertiary (probably Pliocene). A total maximum right-lateral offset rate of 3.3 mm/a. The age of the sedimentary fill o[approximately] the La Gonzalez pull-apart basin suggests that the 7-9 km right-lateral offset necessary to produce it took place in Middle to Late Pleistocene time. The majority of seismic events are well aligned with the main fault trace; minor events are distributed in a belt several kilometers wide. Focal depth is typically 15 km and focal mechanisms indicate an average east-west compression across the zone. Return periods of 135-460 a (Richter M = 8), 45-70 a (M = 7), and 7-15 a (M = 6) have been calculated. Geodetic studies of several sites along the zone indicate compressive and right-lateral components; at Mucubaji the rate of right-lateral displacement observed is about 1 mm every 5 months (15 a of measurements).
Education and the Labor Market in Venezuela, 1975-1984.
ERIC Educational Resources Information Center
Psacharopoulos, George; Steier, Francis
Examines various education-related aspects of Venezuela's labor market for 1975-1984, using a sample of 40,000 workers. Education returns have declined only two percent during a rapid educational expansion period. The increased supply of educated persons influenced the narrowing of earnings differentials and led to more equitable income…
78 FR 58556 - Silicomanganese From India, Kazakhstan, and Venezuela
Federal Register 2010, 2011, 2012, 2013, 2014
... Venezuela. Background The Commission instituted these reviews on October 1, 2012 (77 FR 59970) and determined on January 4, 2013 that it would conduct full reviews (78 FR 4437, January 22, 2013). Notice of... Commission, Washington, DC, and by publishing the notice in the Federal Register on February 21, 2013 (78...
The Educational System of Venezuela. Education around the World.
ERIC Educational Resources Information Center
Nemeth, Edward J.
History, structure, legal bases, and planned reforms of the educational system of Venezuela are discussed. The conflicting roles of church and state in administering education have been reconciled within the past two decades, with resultant increases in enrollment and government financing. Curriculum regulation, coordination, and supervision are…
State-Led Education for Democratic Socialism: Venezuela's Education Missions
ERIC Educational Resources Information Center
Duffy, Maura
Venezuela's "Bolivarian Revolution" is conceptualised as an anti-neoliberal project that aims to promote fundamental changes in the configuration of political power via processes of state-grassroots collaboration. Central to this process is an emphasis on the key role of education in the development of a 21st Century socialism based on…
Late Pleistocene carbonate dissolution in the Venezuela Basin, Caribbean Sea
Cofer-Shabica, N.B.; Peterson, L.C.
Piston cores from water depths greater than 4000 m in the Venezuela Basin (Caribbean Sea) provide continuous late Pleistocene records of carbonate dissolution and accumulation. The authors examination of multiple dissolution indices indicate that, at least for the last 150,000 years, dissolution of carbonate in the Venezuela Basin has been more intense during interglacial than glacial periods, a pattern opposite to more general observations from the deep Atlantic and Gulf of Mexico. By virtue of its shallow sill depth (1815 m), the Venezuela Basin is relatively isolated from the mainstream of Atlantic thermohaline circulation, and presently is filled with homogeneous, relatively warm (3.8/sup 0/C) waters primarily derived from Upper North Atlantic Deep Water. During the last glacial, the enhanced preservation of carbonate in the Venezuela Basin suggests the presence of a less corrosive, more oxygenated water mass in the Atlantic near sill depth. However, this simple interpretations is potentially complicated by past changes in the rain of biogenic materials from surface waters to the deep basin in what must be an essentially closed system below sill depth. Their observations of increased interglacial dissolution may help to explain previously noted discrepancies in the local glacial to interglacial amplitude of delta/sup 18/O variations recorded by coccoliths and planktonic foraminifera.
Molecular Epidemiologic Source Tracking of Orally Transmitted Chagas Disease, Venezuela
Segovia, Maikell; Martínez, Clara E.; Messenger, Louisa A.; Nessi, Anaibeth; Londoño, Juan C.; Espinosa, Raul; Martínez, Cinda; Alfredo, Mijares; Bonfante-Cabarcas, Rafael; Lewis, Michael D.; de Noya, Belkisyolé A.; Miles, Michael A.; Llewellyn, Martin S.
Oral outbreaks of Chagas disease are increasingly reported in Latin America. The transitory presence of Trypanosoma cruzi parasites within contaminated foods, and the rapid consumption of those foods, precludes precise identification of outbreak origin. We report source attribution for 2 peri-urban oral outbreaks of Chagas disease in Venezuela via high resolution microsatellite typing. PMID:23768982
Pedernales oilfield, eastern Venezuela: The first 100 years
Gluyas, J.; Oliver, J.; Wilson, W.
Petroleum seeps and surface tar mats attracted oil explorers to Pedernales in eastern Venezuela 100 years ago. Commercial production from the Pedernales Field was established by Creole in 1933. In three production periods, broken by WWII and the end of the Creole-Texaco refining contract, Creole and Lagoven produced about 60 MMSTB from about 60 wells in about 60 years. Peak production was in the late 1950s, when the field delivered 12,000 BOPD. Production was stopped in 1986. In March 1993, BP Venezuela acquired the license to reactivate Pedernales on behalf of Lagoven, and BP`s first well in the field was drilled in August 1994. A second was completed in early 1995. The production from each well was sufficiently encouraging for commerciality to be declared in March 1995. Phase 1 of the field reactivation demanded a production rate of 11,500 BOPD. As of now (September, 1995) six wells, including one gas disposal well, have been completed. Wells have been placed using a combination of old well data and mapping based on a close spaced 2D seismic survey shot in early 1994. Results from these first few wells indicate that the required production rate will be achieved despite severely depleted reservoir pressures. This paper tells the story of reactivation and re-evaluation of one of eastern Venezuela`s oldest oilfields.
A contribution to the centipede fauna of Venezuela (Chilopoda: Scolopendromorpha).
Schileyko, Arkady A
The descriptions of twelve Venezuelan Scolopendromorpha, a list of species, identification key and detailed list of localities are presented. Cryptops (C.) venezuelae Chamberlin, 1939, known only from the holotype has been re-described and Scolopendra conjungens Muralewicz, 1913 reduced to a junior synonym of Scolopendra angulata Newport, 1844 syn. nov. PMID:24989735
A biostratigraphic sequence analysis in Cretaceous sediments from Eastern Venezuela
Paredes, I.; Carillo, M.; Fasola, A.; Luna, F. )
This paper presents the results of a high resolution biostratigraphic study integrated with petrophysic analyses, of the Late Cretaceous sequence in several wells from the Maturin Sub-Basin, Eastern Venezuela. The main objective of this study is to integrate the different faunal and floral assemblages to the sedimentological evolution of the basin using sequential analysis techniques. This technique was applied using mainly terrestrial and marine palynomorphs which were relatively abundant and diverse as compared to the scarcity of foraminifera and nonnofossils. Based on the percentages of abundance and the diversity of the different groups of microfoss it was possible to establish the maximum flooding surfaces and condensation levels which allowed the definition of the possible candidates for the sequence boundaries. On the other hand, the identified bioevents made possible the definition of the chronostratigraphic datums of the sequence under study. The results obtained will contribute to optimize the exploration and development programs of the oil fields in Eastern Venezuela.
A new species of Corydalus Latreille from Venezuela (Megaloptera, Corydalidae).
Contreras-Ramos, Atilano; von der Dunk, Klaus
A new species of dobsonfly, Corydalus wanningeri, from Venezuela, is described and illustrated. It superficially resembles Corydalus neblinensis Contreras-Ramos, with a uniform reddish coloration of body and wings. Yet, because of male genitalic structure it might be closely related to Corydalus crossi Contreras-Ramos. Specimens were collected from a rain forest transitional zone between the Orinoco lowlands and the Gran Sabana plateau, in Bolívar state. This is the 15(th) species of Corydalus to be recorded from Venezuela, rendering this the country with the highest number of documented Corydalus species. A key to the sexually dimorphic, long-mandibled Venezuelan species of the genus is provided. PMID:21594032
Building a medicine bank for Venezuela. AIDS treatment access.
A partnership began in 1994 between United Against AIDS International (UAAI) of New York and Accion Ciudadana Contra el SIDA (ACCSI) of Venezuela has led to the development of a volunteer infrastructure including medicine and medical supply donors, airlines, truck drivers, customs officials, storage facilities, and medical personnel to bring treatment to people with AIDS (PWA) in Venezuela. Renate Koch, ACCSI director, began bringing medications home to Venezuela in early 1994, following a visit to New York City, where she met with representatives of ACT UP], the Global Network of People with AIDS, and other New York-based HIV/AIDS associations. Hugh Ward, who founded UAAI to provide HIV/AIDS drugs to PWA in Venezuela, later met with Koch and several other nongovernmental organizations in Caracas. Ward explained that most unused medicines and treatments given to people with AIDS in the US are thrown away after the patient has died or when the patient's health condition demands an alternate treatment. A network of New York-based AIDS organizations and doctors' groups now collects the medicines returned to them by PWA for donation to the medicine bank program. Once the medicines are received in Caracas, they are stored at Accion Ecumenica health clinic for distribution to PWA. While there is always a need for more medicines and supplies, the current network is able to back-stock enough quantities to ensure that patients will receive consistent and sustained treatment. Limited quantities of retrovirals and protease inhibitors are included in the medicine bank. PMID:12321757
Radioisotope Concentration in Lake Sediments of Maracaibo, Venezuela
Salas, A. Rangel; Viloria, T.; Sajo-Bohus, L.; Barros, H.; Greaves, E. D.; Palacios, D.
Maracaibo Lake is one of the most important water basing and oil producing regions in Venezuela. Changes in the local environment have been monitored for chemical pollution in the past. For this study we selected a set of sediment samples collected in the shore and analyzed for its radioisotope content. Results show the gamma emitting isotopes distribution. Isotopes concentrations have been determined within the natural K, Th and U families.
Research in seismology and earthquake engineering in Venezuela
Urbina, L.; Grases, J.
After the July 29, 1967, damaging earthquake (with a moderate magnitude of 6.3) caused widespread damage to the northern coastal area of Venezuela and to the Caracas Valley, the Venezuelan Government decided to establish a Presidential Earthquake Commission. This commission undertook the task of coordinating the efforts to study the after-effects of the earthquake. The July 1967 earthquake claimed numerous lives and caused extensive damage to the capital of Venezuela. In 1968, the U.S Geological Survey conducted a seismological field study in the northern coastal area and in the Caracas Valley of Venezuela. the objective was to study the area that sustained severe, moderate, and no damage to structures. A reported entitled Ground Amplification Studies in Earthquake Damage Areas: The Caracas Earthquake of 1967 documented, for the first time, short-period seismic wave ground-motion amplifications in the Caracas Valley. Figure 1 shows the area of severe damage in the Los Palos Grantes suburb and the correlation with depth of alluvium and the arabic numbers denote the ground amplification factor at each site in the area. the Venezuelan Government initiated many programs to study in detail the damage sustained and to investigate the ongoing construction practices. These actions motivated professionals in the academic, private, and Government sectors to develops further capabilities and self-sufficiency in the fields of engineering and seismology. Allocation of funds was made to assist in training professionals and technicians and in developing new seismological stations and new programs at the national level in earthquake engineering and seismology. A brief description of the ongoing programs in Venezuela is listed below. these programs are being performed by FUNVISIS and by other national organizations listed at the end of this article.
Venezuela recasts itself as a new frontier in the Americas
Reinsch, A.E.
In January of this year, Venezuela captured the attention of the international energy community by welcoming back the foreign oil companies that, 20 years earlier, it had shut out of the country by nationalizing the hydrocarbon sector. The tool used to attract that attention, a new exploration bidding round, is the most publicized event staged to date in the country`s aperture process. However, it is only the latest in a series of steps taken by officials to bring international oil and gas companies back to Caracas. Venezuela`s physical attraction is easily understood. The country possesses roughly one-half of Latin America`s (including Mexico) 125 billion bbl of established, conventional crude oil reserves, plus an estimated 300 billion bbl of additional, nonconventional reserves in the ultra-heavy crude belt of the Orinoco basin. Averaging 2.8 million bpd in 1996, Venezuelan crude production represents over 35% of regional oil output. Natural gas reserves total 138 Tcf, or just over one-half of the region`s total reserves of 274 Tcfg. Annual gas output averages just under 5 Tcf, of which roughly 30% is reinjected as part of tertiary oil recovery schemes. This paper reviews the incentives, deregulation, and government policies to restore the oil and gas industry to the country.
Geologic map of the Venezuela part of the Puerto Ayacucho 2 degrees x 3 degrees Quadrangle, Amazonas Federal Territory, Venezuela
Wynn, Jeffrey C.; Olmore, Steven D.; Mendoza, Vicente; García, Andrés; Rendon, Ines; Estanga, Yasmin; Rincon, Haydee; Martinez, Felix; Lugo, Elis; Rivero, Nelson; Schruben, Paul G.
This map is one of a series of 1:500,000-scale maps that, along with several other products, stems from a cooperative agreement between the U.S. Geological Survey (USGS) and the Corporacion Venezolana de Guayana, Tecnica Minera, C.A. (TECMIN), a Venezuelan Government-owned mining and mineral exploration company. The agreement covered cooperative work carried out in the Precambrian Shield of southern Venezuela during 1987-1991 and included a geologic and mineral resource inventory, technology transfer, and scientific training (Wynn and others, in press). The Precambrian Guayana Shield (Escudo de Guyana, not to be confused with the neighboring country of Guyana) includes some of the oldest known rocks in the world (Mendoza, 1977) and also covers parts of neighboring Guyana, Surinam, French Guiana, Columbia, and Brazil. In Venezuela, it underlies most of Bolivar state and all of the Amazonas Federal Territory (see index map).
Radioactive source materials in Los Estados Unidos de Venezuela
Wyant, Donald G.; Sharp, William N.; Rodriguez, Carlos Ponte
This report summarizes the data available on radioactive source materials in Los Estados Unidos de Venezuela accumulated by geologists of the Direccions Tecnica de Geolgia and antecedent agencies prior to June 1951, and the writers from June to November 1951. The investigation comprised preliminary study, field examination, office studies, and the preparation of this report, in which the areas and localities examined are described in detail, the uranium potentialities of Venezuela are summarized, and recommendations are made. Preliminary study was made to select areas and rock types that were known or reported to be radioactive or that geologic experience suggests would be favorable host for uranium deposits, In the office, a study of gamma-ray well logs was started as one means of amassing general radiometric data and of rapidly scanning many of ye rocks in northern Venezuela; gamma-ray logs from about 140 representative wells were examined and their peaks of gamma intensity evaluated; in addition samples were analyzed radiometrically, and petrographically. Radiometic reconnaissance was made in the field during about 3 months of 1951, or about 12 areas, including over 100 localities in the State of Miranda, Carabobo, Yaracuy, Falcon, Lara, Trujillo, Zulia, Merida, Tachira, Bolivar, and Territory Delta Amacuro. During the course of the investigation, both in the filed and office, information was given about geology of uranium deposits, and in techniques used in prospecting and analysis. All studies and this report are designed to supplement and to strengthen the Direccion Tecnica de Geologias's program of investigation of radioactive source in Venezuela now in progress. The uranium potentialities of Los Estados de Venezuela are excellent for large, low-grade deposits of uraniferous phospahtic shales containing from 0.002 to 0.027 percent uranium; fair, for small or moderate-sized, low-grade placer deposits of thorium, rare-earth, and uranium minerals; poor, for
Paleoseismology in Venezuela: Objectives, methods, applications, limitations and perspectives
NASA Astrophysics Data System (ADS)
Audemard M., Franck A.
The privileged location of Venezuela along an active interplate deformation belt, despite of being a "so-called" developing country, has led to a long paleoseismic tradition as attested by 45 trench assessments since 1968. Since then, a first 2-trench study was carried out by the American Woodward-Clyde company across the Oca fault at Sinamaica. Since 1980, all further paleoseismic studies have been performed by FUNVISIS and the Uribante-Caparo hydroelectric project (southern Mérida Andes) became their first assessment where 22 huge trenches were bulldozer-dug. Except for these Compañía Anónima de Administración y Fomento Eléctrico (CADAFE) financed trenches and two others, all other assessments were for Petróleos de Venezuela S. A. -PDVSA-. In this paper, geographic and geologic factors, as well as logistic limitations, conditioning success in paleoseismic studies by trenching, shall be discussed based on the Venezuelan experience developed over the years. The scientific contribution of this approach refer to: confirmation of Holocene fault activity, slip-per-event and average slip rate of a given fault (or segment), seismic potential (repeat of maximum credible earthquakes) of known faults, fault segmentation, fault interaction as consequence of stress loading by stick-slip on contiguous faults, time-space distribution of seismic activity along a given tectonic feature, seismotectonic association of historical earthquakes and landscape evolution on the short term and its implications on the long-term evolution (poorly discussed since this is really part of the field of Neotectonics). In recent years (since 1999), a new approach has been introduced in Venezuela consisting in complementing the seismic history derived from trenching studies with the evaluation of seismically induced perturbations in the continuous Quaternary sedimentary record of (either active or fossil) lakes. The future of this discipline in Venezuela heads to more trenching and lake
Interruption of Onchocerca volvulus transmission in Northern Venezuela
Background Onchocerciasis is caused by Onchocerca volvulus and transmitted by Simulium species (black flies). In the Americas, the infection has been previously described in 13 discrete regional foci distributed among six countries (Brazil, Colombia, Ecuador, Guatemala, Mexico and Venezuela) where more than 370,000 people are currently considered at risk. Since 2001, disease control in Venezuela has relied on the mass drug administration to the at-risk communities. This report provides empirical evidence of interruption of Onchocerca volvulus transmission by Simulium metallicum in 510 endemic communities from two Northern foci of Venezuela, after 10–12 years of 6-monthly Mectizan® (ivermectin) treatment to all the eligible residents. Methods In-depth entomologic and epidemiologic surveys were serially conducted from 2001–2012 in selected (sentinel and extra-sentinel) communities from the North-central (NC) and North-east (NE) onchocerciasis foci of Venezuela in order to monitor the impact of ivermectin treatment. Results From 2007–2009, entomological indicators in both foci confirmed that 0 out of 112,637 S. metallicum females examined by PCR contained L3 infection in insect heads. The upper bound of the 95% confidence intervals of the infective rate of the vector reached values below 1% by 2009 (NC) and 2012 (NE). Additionally, after 14 (NC) and 22 (NE) rounds of treatment, the seasonal transmission potential (±UL CIs) of S. metallicum was under the critical threshold of 20 L3 per person per season. Serological analysis in school children < 15 years-old demonstrated that 0 out of 6,590 individuals were harboring antibodies to Ov-16. Finally, epidemiological surveys made during 2010 (NC) and 2012 (NE) showed no evidence of microfilariae in the skin and eyes of the population. Conclusions These results meet the WHO criteria for absence of parasite transmission and disease morbidity in these endemic areas which represent 91% of the population previously at
Socio-Economic Aspects of National Communication Systems: III. Radio Broadcasting in Venezuela. Communication and Society, 12.
ERIC Educational Resources Information Center
Capriles, Oswaldo; And Others
The third in a series that examines the role of radio broadcasting in the process of socioeconomic and cultural change in three countries with different types of broadcasting organization--Austria, Czechoslovakia, and Venezuela--this volume focuses on Venezuela. An overview of radio broadcasting in Venezuela describes various aspects and provides…
Chemical composition and antidiabetic activity of Opuntia Milpa Alta extracts.
Luo, Chuan; Zhang, Wannian; Sheng, Chunquan; Zheng, Chengjian; Yao, Jianzhong; Miao, Zhenyuan
Three new compounds, 1-3, and 20 known compounds were isolated from the AcOEt and BuOH extract of edible Opuntia Milpa Alta. The petroleum ether extract was examined by GC and MS. A total of 26 compounds were identified, representing 95.6% of the total extract, phytosterol (36.03%) being the most abundant component, and polyunsaturated fatty acids (18.57%) represented the second largest group, followed by phytol (12.28%), palmitic acid, palmitate (13.54%), vitamin E (4.51%), and other compounds (7.47%). The effects of various extracts from edible Opuntia Milpa Alta (petroleum ether extract, AcOEt extract, BuOH extract, aqueous extract, H₂O parts) and the positive control (received dimethylbiguanide) were tested on streptozotocin (STZ)-induced diabetic mice. The results indicated that all the treatment groups could significantly decrease blood glucose levels in STZ-induced diabetic mice compared to the model control group (P<0.01), except the aqueous extract group (P<0.05). Especially, the petroleum ether extract group and the positive control group showed remarkable decrease of blood glucose levels. Taken together, the results indicate that the petroleum ether extract is the major hypoglycemic part in edible Opuntia Milpa Alta, which may be developed to a potential natural hypoglycemic functional ingredient. PMID:21161999
77 FR 59970 - Silicomanganese From India, Kazakhstan, and Venezuela; Institution of Five-Year Reviews...
Federal Register 2010, 2011, 2012, 2013, 2014
... silicomanganese from India, Kazakhstan, and Venezuela (73 FR 841, January 4, 2008). The Commission is now... amended at 74 FR 2847 (January 16, 2009). \\1\\ No response to this request for information is required if a..., and Venezuela (67 FR 36149). Following the five-year reviews by Commerce and the Commission,...
78 FR 4437 - Silicomanganese From India, Kazakhstan, Venezuela: Notice of Commission Determination To Conduct...
Federal Register 2010, 2011, 2012, 2013, 2014
... of institution (77 FR 59970, October 1, 2012) was adequate and that the respondent interested party... COMMISSION Silicomanganese From India, Kazakhstan, Venezuela: Notice of Commission Determination To Conduct... duty orders on silicomanganese from India, Kazakhstan, and Venezuela would be likely to lead...
Four new species of Andean Pilea (Urticaceae), with additional notes on the genus in Venezuela.
Dorr, Laurence J; Stergios, Basil
Four new species of Pilea (Urticaceae) from the Andes of Venezuela are described and illustrated: Pileamatthewii sp. nov., Pileamiguelii sp. nov., Pileanicholasii sp. nov., and Pileanidiae sp. nov. The affinities of these species and their positions within the informal classifications of Pilea proposed by Weddell and Killip are discussed. Notes on other species of Pilea found in Venezuela also are presented. PMID:25383012
78 FR 60846 - Silicomanganese From India, Kazakhstan, and Venezuela: Continuation of Antidumping Duty Orders
Federal Register 2010, 2011, 2012, 2013, 2014
... FR 59897 (October 1, 2012). \\2\\ See Silicomanganese From India, Kazakhstan, and Venezuela: Final Results of the Expedited Second Sunset Reviews of the Antidumping Duty Orders, 78 FR 9034 (February 7, 2013). \\3\\ See Silicomanganese From India, Kazakhstan, and Venezuela: Determination, 78 FR...
78 FR 77423 - Ferrosilicon From the Russian Federation and Venezuela: Postponement of Preliminary...
Federal Register 2010, 2011, 2012, 2013, 2014
... Russian Federation and Venezuela: Initiation of Antidumping Duty Investigations, 78 FR 49471 (August 14, 2013) (``Initiation Notice''). \\2\\ See id., 78 FR at 49474. As explained in the memorandum from the... International Trade Administration Ferrosilicon From the Russian Federation and Venezuela: Postponement...
Using the Five Themes of Geography To Teach about Venezuela and Mexico.
ERIC Educational Resources Information Center
Sunal, Cynthia Szymanski; Christensen, Lois
Activities that employ the five themes of geography--location, place, relationships within places, movement, and regions--to teach about Venezuela and Mexico are described in this document. Each theme has objectives, a list of materials, and three types of activities--exploration, invention, and expansion. Background information on Venezuela and…
Earnings and Education in Venezuela: An Update from the 1987 Household Survey.
ERIC Educational Resources Information Center
Psacharopoulos, George; Alam, Asad
Uses data from Venezuela's 1987 Household Survey to update returns to education and compare them to 1975 and 1984 figures. Returns to education have been maintained despite the educational explosion occurring in Venezuela during the period investigated. Although higher education is most heavily subsidized, primary education remains the most…
A new approach to the oil business in Venezuela
Pradas, F.; Valdes, G. )
Petroleos de Venezuela S.A. (PDVSA) has been meeting during the past two years with a considerable number of companies (groups) with a view to possible associations for the reactivation of known fields, joint activities in barely explored areas and the exploitation, refining, upgrading and marketing of crudes from the Orinoco Belt holder of immense reserves of extra-heavy crudes and bitumens. In Venezuela, a new approach to the oil business is under way. On January 1976, the law nationalizing the Venezuelan oil industry became effective establishing that the government retains the sole rights to the country's petroleum industry. However, Article 5 of the law made provision for associations in cases considered to be of [open quotes]National Interest.[close quotes] PDVSA became the wholly government-owned holding entity, encompassing 26 subsidiaries and affiliates. Other energy segments, particularly coal and petrochemicals, were not included in the law and since 1984 several associations with non-governmental entities have been established in Venezuela and very valuable experience has been garnered. Similarly, partnerships and acquisitions have been made in Europe and USA, mostly in refining, through PDVSA. The international petroleum industry foresees a modest, but steady increase in production during the coming decade, particularly in the second half of the nineties. This effect, added to the globalization concept, is making the traditional vertically integrated oil companies look for diverse [open quotes]lateral[close quotes] associations between groups, private and/or state owned with common interests, that will give greater security to sources of supply and market share.
Zonation of hydric regimens in Venezuela based on rainfall characteristics
NASA Astrophysics Data System (ADS)
Lobo, D.; Verbist, K.; Gabriels, D.; Puche, M.; Bracho, G.; Soto, G.; Santibañez, F.
The climate in Venezuela is a product of a complex combination and interaction of meteorological and geographical factors such as the geographic location either north of Ecuador or in the tropics, and the presence of warm waters north and northeast, a vast tropical moist forest south and a mountain range west. In order to delimit the different climatic zones in Venezuela, a zoning of water regimes were used to classify climate indices primarily on rainfall parameters. A first index used was the length of a dry period, corresponding to the number of months in the year when precipitation is less than half of the reference evapotranspiration. Another index was the Aridity Index (Ia) proposed by UNEP (1997), for which calculations were based on values of average annual rainfall of the stations of the FAO database (1984, 2000). The reference evapotranspiration (ETo) was calculated by the CIRH program version 2.0 (Santibanez, 2005), which allows the calculation of ETo by the FAO (Allen et al.1998) or by the original Penman-Monteith formula, by Thornthwaite (1948), Turc (1961) or by Ivanov (1996). The results show that the distribution of the climatic regimes of Venezuela is determined by rainfall patterns. The central region is dominated by a sub-humid regime surrounded by a humid regime. The southern region is dominated by hyper-humid, hydric and hyper-hydric regimes, as well as the most western and eastern regions. In the northern and central-western regions the semiarid, arid and hyper-arid regimes dominate.
Venezuela No. 1 oil import source in S. America
Not Available
This paper reports that with the exception of Venezuela, the U.S. is likely to import much oil from South American countries through 2010, the General Accounting Office reports. GAO, a congressional watchdog agency, noted the U.S. imports about 4% of its oil from Colombia, Ecuador, and Trinidad and Tobago and possibly could import from Argentina, Bolivia, Brazil, Chile, and Peru in the future. It the the eight countries' crude oil reserves are expected to increase about 30% by 2000, then slide about 2% by 2010. Their oil production is expected to climb about 21% over 1990 by 2000, then level off until 2010.
A new species of Coespeletia (Asteraceae, Millerieae) from Venezuela.
Diazgranados, Mauricio; Morillo, Gilberto
A new species of Coespeletia from the páramos of Mérida (Venezuela) is described here. This species, named Coespeletia palustris, is found in a few marshy areas of the páramo. It is closely related to C. moritziana, but differs from it in a smaller number of florets in the capitula, larger ray flowers with longer ligulae and longer linguiform appendages, smaller pollen grains, larger cypselae, ebracteate scapes, leaves and inflorescences with more whitish indumentum, larger leaf sheaths, and marshy habitat. PMID:24399890
[Microbiological quality of vanilla ice cream manufactured in Caracas, Venezuela].
de Tamsut, L S; García, C E
A total of 122 samples of vanilla ice cream, the base product used for all flavors, prepared by eight different large firms at the Metropolitan Area of Caracas, Venezuela, were analyzed for aerobic mesophilic and psicrophilic bacteria, Staphylococcus aureus, Enterobacteriaceae, and Filamentous fungi. Findings revealed that within the sampling, 56.6% complied with the international standards proposed for aerobic mesophilic bacteria, 68% for Staphylococcus aureus, and 23% for Enterobacteriaceae. Three serotypes of enteropathogenic Escherichia coli, one of Salmonella, and one of Shigella were found. Ten genera of Filamentous fungi were isolated and identified. PMID:2487021
Present Status of Historical Seismicity Studies in Colombia and Venezuela
NASA Astrophysics Data System (ADS)
Sarabia, A.; Cifuentes, H.; Altez Ortega, R.; Palme, C.; Dimate, C.
After the publication of the SISRA (CERESIS-1985) regional project, a unified catalog of seismic parameters and intensities for South America, researchers in historical seismicity have continued advancing on different scales in the area of this study of seismic hazard. The most important initiatives carried out in this area in Colombia and Venezuela can be grouped as follows: a) Reviews of destructive earthquakes in national and international historic archives, principally by Altez and FUNVISIS in Venezuela and Espinosa, Salcedo, and Sarabia et al in Colombia, leading to the preparation of seismologic catalogues, scientific and dissemination articles, reports, books, among others. b) Organization and systematization of historic information to develop public domain data bases and information, specifically the Historic Seismologic Teleinformation System in Venezuela, carried out between 2004 and 2008 under the coordination of Christl Palme and accessible on-line: http://sismicidad.ciens.ula.ve. As well, the "Historia Sísmica de Colombia 1550-1830" (Seismic History in Colombia 1550-1830) data base, in CD-ROM, by Espinosa Baquero (2003) and the historic seismicity information system of Colombia (Servicio Geológico Colombiano-Universidad Nacional de Colombia), published on the internet in 2012: http://agata.ingeominas.gov.co:9090/SismicidadHistorica/. c) Macroseismic studies for the development of intensity attenuation equations and the quantification and revaluation of basic historic earthquake parameters using isoseismal maps (Rengifo et al., Palme et al., Salcedo et al., among others) and procedures such as Boxer and Bakun & Wentworth (Palme et al., Dimaté, among others), which have produced significant changes in the parameters of some of the large earthquakes. d) Symposiums of researchers to promote interest and development in the discipline, including Jornadas Venezolanas de Sismología Histórica (Venezuelan Congress of Historical Seismology), held
A new species of Coespeletia (Asteraceae, Millerieae) from Venezuela
Diazgranados, Mauricio; Morillo, Gilberto
Abstract A new species of Coespeletia from the páramos of Mérida (Venezuela) is described here. This species, named Coespeletia palustris, is found in a few marshy areas of the páramo. It is closely related to C. moritziana, but differs from it in a smaller number of florets in the capitula, larger ray flowers with longer ligulae and longer linguiform appendages, smaller pollen grains, larger cypselae, ebracteate scapes, leaves and inflorescences with more whitish indumentum, larger leaf sheaths, and marshy habitat. PMID:24399890
Paralytic shellfish poisoning (PSP) in Margarita Island, Venezuela.
La Barbera-Sánchez, Amelia; Franco Soler, Jose; Rojas de Astudillo, Luisa; Chang-Yen, Ivan
A severe outbreak of Paralytic Shellfish Poisoning (PSP) occurred in Manzanillo and Guayacán, northwestern coast of Margarita Island, Venezuela, between August and October 1991. A bloom of dinoflagellates including Prorocentrum gracile, Gymnodinium catenatum and Alexandrium tamarense seemed to be responsible for this outbreak. Levels of PSP toxins in mussels (Perna perna) exceeded the international safety limit of saxitoxin, 80 microg STX/100 microg meat. PSP toxin values varied between 2548 and 115 microg STX/100 g meat in Manzanillo, and between 1422 and 86 microg STX/100 g meat in Guayacán. At both locations, the highest levels were detected in August, when 24 patients exhibited typical symptoms of PSP toxicity after consuming cooked mussels (16 required hospitalization). A high pressure liquid chromatographic (HPLC) procedure was recently used on the 1991 samples. The major toxin detected in samples of both locations was decarbamoyl saxitoxin (dcSTX), but low concentrations of saxitoxin were also found in Manzanillo samples. Gonyautoxins GTX1, GTX2 and GTX3 were detected only at Guayacán, while in both locations, decarbamoylgonyatouxin (dcGTX2,3) toxins were detected. These findings represent the first time that causative toxins of PSP in Venezuela have been chemically identified, and confirm the presence of dcSTX and dcGTX in mussels from the Caribbean Sea. The presence of dcSTX and dcGTX in shellfish is indicative that Gymnodinium catenatum was a causative organism for outbreak of PSP. PMID:17465121
AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA.
Teixeira, Bertinellys; Rodulfo, Hectorina; Carreño, Numirin; Guzmán, Militza; Salazar, Elsa; De Donato, Marcos
The enzymatic modification of aminoglycosides by aminoglycoside-acetyltransferases (AAC), aminoglycoside-adenyltransferases (AAD), and aminoglycoside-phosphotransferases (APH), is the most common resistance mechanism in P. aeruginosa and these enzymes can be coded on mobile genetic elements that contribute to their dispersion. One hundred and thirty seven P. aeruginosa isolates from the University Hospital, Cumana, Venezuela (HUAPA) were evaluated. Antimicrobial susceptibility was determined by the disk diffusion method and theaac, aadB and aph genes were detected by PCR. Most of the P. aeruginosa isolates (33/137) were identified from the Intensive Care Unit (ICU), mainly from discharges (96/137). The frequency of resistant P. aeruginosaisolates was found to be higher for the aminoglycosides tobramycin and amikacin (30.7 and 29.9%, respectively). Phenotype VI, resistant to these antibiotics, was the most frequent (14/49), followed by phenotype I, resistant to all the aminoglycosides tested (12/49). The aac(6´)-Ib,aphA1 and aadB genes were the most frequently detected, and the simultaneous presence of several resistance genes in the same isolate was demonstrated. Aminoglycoside resistance in isolates ofP. aeruginosa at the HUAPA is partly due to the presence of the aac(6´)-Ib, aphA1 andaadB genes, but the high rates of antimicrobial resistance suggest the existence of several mechanisms acting together. This is the first report of aminoglycoside resistance genes in Venezuela and one of the few in Latin America. PMID:27007556
[A new species of Tityus (Scorpiones: Buthidae) from Turimiquire, Venezuela].
De Sousa, Leonardo; Manzanilla, Jesús; Parrilla-Alvarez, Pedro
We describe a new species of Buthid scorpion, Tityus quirogae, from the Turimiquire mountains, eastern side of the La Costa range, Monagas and Sucre States, Venezuela. It is morphologically similar to T. nematochirus and T. meridanus. It differs from these species in the distribution of the dorsal femoral trichobothria and in the following combination of characters: (1) I caudal segment with two parallel ventral keels. Caudal segments II to IV with ventral keels that are double in the extremes of the segments and single in the middle, (2) noticeable sexual dimorphism, especially in pedipalp shape; the male chelae are markedly thin and long, (3) number of pectineous teeth (male: 18 in each pecten; female: 18 in the right pecten and 19 in the left one), and (4) number of denticle rows in the movable finger of the right chela (16 in both sexes). T. quirogae is the first species of this genus, in the Northeastern region of Venezuela, with thin and elongated pedipalps. PMID:18494317
Genetic characterization of rabies field isolates from Venezuela.
de Mattos, C A; de Mattos, C C; Smith, J S; Miller, E T; Papo, S; Utrera, A; Osburn, B I
Twenty samples from cases of rabies in humans and domestic animals diagnosed in Venezuela between 1990 and 1994 and one sample from a vampire bat collected in 1976 were characterized by reactivity to monoclonal antibodies against the viral nucleoprotein and by patterns of nucleotide substitution in the nucleoprotein gene. Three antigenic variants were found: 1, 3, and 5. Antigenic variant 1 included all samples from dogs and humans infected by contact with rabid dogs. Unique substitutions permitted identification of two separate outbreaks of dog rabies in the Maracaibo Depression and Los Llanos region and in the Andean region of Venezuela. Samples from the vampire bat and two head of cattle were characterized as antigenic variant 3 and showed a nucleotide sequence homology of 96 to 98% to each other and to samples of vampire bat-associated rabies throughout Latin America. Ten of the remaining 12 samples were characterized as antigenic variant 5. Genetic studies indicated that 11 of these samples formed a highly homologous and distinctive group but were closely related to samples of vampire bat-associated rabies. The 12th sample of variant 5 (from a cat) showed only 78 to 80% genetic homology to samples of rabies associated with vampire bats. The application of antigenic and genetic typing to rabies surveillance in Latin America is essential to improve control programs. Recognition of the source of outbreaks of dog rabies and identification of wildlife species maintaining sylvatic cycles of rabies transmission permit better utilization of public health resources. PMID:8735118
Raptor abundance and distribution in the Llanos wetlands of Venezuela
Jensen, W.J.; Gregory, M.S.; Baldassarre, G.A.; Vilella, F.J.; Bildstein, K.L.
The Llanos of Venezuela is a 275 000-km2 freshwater wetland long recognized as an important habitat for waterbirds. However, little information exists on the raptor community of the region. We conducted raptor surveys in the Southwestern and Western Llanos during 2000-02 and detected 28 species representing 19 genera. Overall, areas of the Llanos that we sampled contained 52% of all raptor species and more than 70% of the kites, buteos, and subbuteos known to inhabit Venezuela. Regional differences in the mean number per route for four of the 14 most common species, the Crested Caracara (Caracara plancus), Black-collared Hawk (Busarellus nigricollis), American Kestrel (Falco sparverius), and Osprey (Pandion haliaetus), were significant (P < 0.0018) in relation to the wet or dry seasons. Of the 14 less common species, six were detected in only one season (wet or dry). The Southwestern and Western regions of the Llanos support a rich raptor community composed primarily of nonmigratory wetland-dependent and upland-terrestrial species. ?? 2005 The Raptor Research Foundation, Inc.
The periodicity of Plasmodium vivax and Plasmodium falciparum in Venezuela.
Grillet, María-Eugenia; El Souki, Mayida; Laguna, Francisco; León, José Rafael
We investigated the periodicity of Plasmodium vivax and P. falciparum incidence in time-series of malaria data (1990-2010) from three endemic regions in Venezuela. In particular, we determined whether disease epidemics were related to local climate variability and regional climate anomalies such as the El Niño Southern Oscillation (ENSO). Malaria periodicity was found to exhibit unique features in each studied region. Significant multi-annual cycles of 2- to about 6-year periods were identified. The inter-annual variability of malaria cases was coherent with that of SSTs (ENSO), mainly at temporal scales within the 3-6 year periods. Additionally, malaria cases were intensified approximately 1 year after an El Niño event, a pattern that highlights the role of climate inter-annual variability in the epidemic patterns. Rainfall mediated the effect of ENSO on malaria locally. Particularly, rains from the last phase of the season had a critical role in the temporal dynamics of Plasmodium. The malaria-climate relationship was complex and transient, varying in strength with the region and species. By identifying temporal cycles of malaria we have made a first step in predicting high-risk years in Venezuela. Our findings emphasize the importance of analyzing high-resolution spatial-temporal data to better understand malaria transmission dynamics. PMID:24149288
AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA
TEIXEIRA, Bertinellys; RODULFO, Hectorina; CARREÑO, Numirin; GUZMÁN, Militza; SALAZAR, Elsa; DONATO, Marcos DE
The enzymatic modification of aminoglycosides by aminoglycoside-acetyltransferases (AAC), aminoglycoside-adenyltransferases (AAD), and aminoglycoside-phosphotransferases (APH), is the most common resistance mechanism in P. aeruginosa and these enzymes can be coded on mobile genetic elements that contribute to their dispersion. One hundred and thirty seven P. aeruginosa isolates from the University Hospital, Cumana, Venezuela (HUAPA) were evaluated. Antimicrobial susceptibility was determined by the disk diffusion method and theaac, aadB and aph genes were detected by PCR. Most of the P. aeruginosa isolates (33/137) were identified from the Intensive Care Unit (ICU), mainly from discharges (96/137). The frequency of resistant P. aeruginosaisolates was found to be higher for the aminoglycosides tobramycin and amikacin (30.7 and 29.9%, respectively). Phenotype VI, resistant to these antibiotics, was the most frequent (14/49), followed by phenotype I, resistant to all the aminoglycosides tested (12/49). The aac(6´)-Ib,aphA1 and aadB genes were the most frequently detected, and the simultaneous presence of several resistance genes in the same isolate was demonstrated. Aminoglycoside resistance in isolates ofP. aeruginosa at the HUAPA is partly due to the presence of the aac(6´)-Ib, aphA1 andaadB genes, but the high rates of antimicrobial resistance suggest the existence of several mechanisms acting together. This is the first report of aminoglycoside resistance genes in Venezuela and one of the few in Latin America. PMID:27007556
Correlation of the Jurassic through Oligocene Stratigraphic Units of Trinidad and Northeastern Venezuela
Algar, S.; Erikson, J.P.
The Jurassic through Oligocene stratigraphies of Trinidad and the Serrenia del Interior of eastern Venezuela exhibit many similarities because of their proximity on the passive continental margins of northeastern South America. A slightly later subsidence in eastern Venezuela, and the generally deeper-water sedimentation in Trinidad, is interpreted to be the result of a serration of the original rift margin, producing an eastern Venezuela promontory and Trinidadian re-entrant. We interpret these serrations to be the result of oblique (NW-SE) spreading of North and South America during Middle and late Jurassic time. The stratigraphies of northeastern Venezuela and Trinidad contrast in the Hauterivan-Albian interval, with dynamic shallow shelf environments prevailing in the Serrenia del Interior and deeper marine submarine-fan deposition in Trinidad. Both areas develop middle to Upper Cretaceous source rocks during a time of eustatic sea level high and widespread oceanic anoxia. 15 refs., 4 fig.
Decentralization and Regionalization in the Ministry of Education: The Case of Venezuela
ERIC Educational Resources Information Center
Hanson, Mark
This research is an effort to analyze the process of organizational change as it takes place within one segment of the public administration mechanism in Venezuela--The Ministry of Education. (Editor/RK)
A Descriptive Chronology of Films by Women in Venezuela, 1952-92.
ERIC Educational Resources Information Center
Schwartzman, Karen
Offers an annotated chronology of Venezuelan films, representing a first step toward a general history of women's filmmaking in Venezuela. Suggests that the participation of women directors closely follows the curve of national film production in general. (RS)
Biological and phylogenetic characterization of a genotype VII Newcastle disease virus from Venezuela: Efficacy of vaccination
Technology Transfer Automated Retrieval System (TEKTRAN)
Here we describe the characterization a virulent genotype VII Newcastle disease virus (NDV) from Venezuela and evaluate the efficacy of heterologous genotype commercial vaccination under field and controlled rearing conditions. Biological pathotyping and molecular analysis were applied. Results sh...
Scorpionism due to Tityus neoespartanus (Scorpiones, Buthidae) in Margarita Island, northeastern Venezuela.
De Sousa, Leonardo; Boadas, Jenny; Kiriakos, Demetrio; Borges, Adolfo; Boadas, Jesús; Marcano, Jenny; Turkali, Iván; De Los Ríos, Miguel
The first two cases of scorpion envenoming caused by Tityus neoespartanus (Buthidae) are described. The accidents took place within human environments (one inside a home and the other inside a school), in the village of La Sierra, Margarita Island, State of Nueva Esparta, northeastern Venezuela. Both cases were moderately severe and developed pancreatic involvement and electrocardiographic abnormalities. This report allows inclusion of Margarita Island among the endemic areas of scorpionism in Venezuela. PMID:18200425
Four new species of Andean Pilea (Urticaceae), with additional notes on the genus in Venezuela
Dorr, Laurence J.; Stergios, Basil
Abstract Four new species of Pilea (Urticaceae) from the Andes of Venezuela are described and illustrated: Pilea matthewii sp. nov., Pilea miguelii sp. nov., Pilea nicholasii sp. nov., and Pilea nidiae sp. nov. The affinities of these species and their positions within the informal classifications of Pilea proposed by Weddell and Killip are discussed. Notes on other species of Pilea found in Venezuela also are presented. PMID:25383012
Characterization of antigenetic serotypes from the dengue virus in Venezuela by means of Grid Computing.
Isea, Raúl; Montes, Esther; Rubio-Montero, Antonio J; Rosales, José D; Rodríguez-Pascual, Manuel A; Mayo, Rafael
This work determines the molecular epidemiology of dengue virus in Venezuela by means of phylogenetic calculations performed on the EELA-2 Grid infrastructure with the PhyloGrid application, an open source tool that allows users performing phylogeny reconstruction in their research. In this study, a total of 132 E nucleotide gene sequences of dengue virus from Venezuela recorded in GenBank(R) have been processed in order to reproduce and validate the topology described in the literature. PMID:20543442
Transmission of Guanarito and Pirital Viruses among Wild Rodents, Venezuela
Milazzo, Mary L.; Cajimat, Maria N.B.; Duno, Gloria; Duno, Freddy; Utrera, Antonio
Samples from rodents captured on a farm in Venezuela in February 1997 were tested for arenavirus, antibody against Guanarito virus (GTOV), and antibody against Pirital virus (PIRV). Thirty-one (48.4%) of 64 short-tailed cane mice (Zygodontomys brevicauda) were infected with GTOV, 1 Alston's cotton rat (Sigmodon alstoni) was infected with GTOV, and 36 (64.3%) of 56 other Alston's cotton rats were infected with PIRV. The results of analyses of field and laboratory data suggested that horizontal transmission is the dominant mode of GTOV transmission in Z. brevicauda mice and that vertical transmission is an important mode of PIRV transmission in S. alstoni rats. The results also suggested that bodily secretions and excretions from most GTOV-infected short-tailed cane mice and most PIRV-infected Alston's cotton rats may transmit the viruses to humans. PMID:22172205
Geology and geochemistry of crude oils, Bolivar coastal fields, Venezuela
Bockmeulen, H.; Barker, C.; Dickey, P.A.
The Bolivar Coastal Fields (BCF) are located on the eastern margin of Lake Maracaibo, Venezuela. They form the largest oil field outside of the Middle East and contain mostly heavy oil with a gravity less than 22/sup 0/ API. Thirty crude oils from the BCF were collected along two parallel and generally southwest-northeast trends. These oils were characterized by their API gravity, percent saturates, aromatics, NSO and asphalitic compounds, gas chromatograms for whole oils, C/sub 4/-C/sub 7/ fractions, and aromatics. Also, 24 associated waters were sampled and analyzed for Ca/sup + +/, Mg/sup + +/, Na/sup +/, HCO/sub 3//sup -/, CO/sub 3//sup - -/, SO/sub 4//sup - -/, pH, and total dissolved solids (TDS). The geological and geochemical significances of these analyses are discussed with particular emphasis on the genesis of the petroleum.
Canine visceral leishmaniasis on Margarita Island (Nueva Esparta, Venezuela).
Zerpa, O; Ulrich, M; Negrón, E; Rodríguez, N; Centeno, M; Rodríguez, V; Barrios, R M; Belizario, D; Reed, S; Convit, J
The frequency of American visceral leishmaniasis affecting humans on Margarita Island, Venezuela, has increased in recent years, and infected dogs appear to constitute the principal source of infection. ELISA tests with Leishmania donovani promastigotes and rK39 antigen from L. chagasi in serum from 541 dogs were positive in 33.1% and 21.6% of the samples, respectively. A second blood sample taken from 50 animals after 8-10 months revealed an increase from 24% to 40% of ELISA positivity to both antigens, suggesting high susceptibility and transmission in the canine population. Among 42 serologically positive dogs, 33% of which showed clinical signs of disease, 79% were positive in polymerase chain reactions using primers specific for the L. donovani complex. Control measures including epidemiological hypersurveillance, the humane sacrifice of infected dogs, and rapid diagnosis and treatment of human cases have been initiated. PMID:11132371
Simuliidae and their relation to human onchocerciasis in northern Venezuela
Lewis, D. J.; de Aldecoa, R. Ibáñez
A study of the vectors of onchocerciasis was carried out in 1961 in northern Venezuela at the request of the Venezuelan Government. This article, based on the report submitted, records various observations made—mainly during the dry season—on the identification and biology of the Simuliidae and on the possibilities of controlling them. Twelve Simulium forms were encountered; special attention was paid to the two common man-biting species; S. exiguum, which was abundant but of uncertain relation to onchocerciasis, and S. metallicum. The authors conclude that S. metallicum is the main or only vector in the area studied, but that S. exiguum might possibly also transmit onchocerciasis in certain places near large streams where it is found in great numbers. PMID:20604129
Potential options to reduce GHG emissions in Venezuela
Pereira, N.; Bonduki, Y.; Perdomo, M.
The Government of Venezuela ratified the United Nations Framework Convention on Climate Change (UNFCCC) in December, 1994. The Convention requires all parties to develop and publish national inventories of anthropogenic greenhouse gas emissions (GHG) as well as national plans to reduce or control emissions, taking into account their common but differentiated responsibilities and their specific national and regional development priorities, objectives, and circumstances. Within this context, the Ministry of Environment and Renewable Natural Resources and the Ministry of Energy and Mines developed the `Venezuelan Case-Study to Address Climate Change`. The study was initiated in October 1993, with the financial and technical assistance of the Government of United States, through the U.S. Country Studies Program (USCSP), and the Global Environment Facility (GEF), through the United Nations Environment Programme (UNEP).
Overcoming Squeezing in the Yacambú-Quibor Tunnel, Venezuela
NASA Astrophysics Data System (ADS)
Hoek, E.; Guevara, R.
The 5 m diameter 23.3 km long Yacambú-Quibor tunnel is designed to carry water through the Andes from the Yacambú dam in the wet tropical Orinoco basin to the semi-arid but fertile Quibor basin in western Venezuela. The tunnel is excavated in silicified and graphitic phyllites at depths of up to 1270 m below surface and extreme squeezing problems have been encountered. Construction involved 8 contracts extending over 32 years with breakthrough being achieved in July 2008. Several excavation methods and various lining designs were used over the years until the adoption of yielding support permitted the Owner and the Contractor to agree that only a circular section would be used and emphasis was placed on developing a routine construction procedure, irrespective of the rock conditions encountered at the face. This paper describes some of the rock engineering issues that were faced during the construction of this tunnel.
Venezuela's stake in US refining may grow: xenophobia addressed
Not Available
Is this an invasion of U.S. oil industry sovereignty, or a happy marriage of upstream and downstream between US and foreign interests. Venezuela, a founding member of the Organization of Petroleum Exporting Countries who has also been a chief supplier to the US during times of peace and war, now owns half of two important US refining and marketing organizations. Many US marketers have felt uneasy about this foreign penetration of their turf. In this issue, for the sake of public information, the entire policy statement from the leader of that Venezuelan market strategy is provided. This issue also contains the following: (1) ED refining netback data for the US Gulf and West Coasts, Rotterdam, and Singapore as of late September, 1987; and (2) ED fuel price/tax series for countries of the Eastern Hemisphere, Sept. 19 edition. 4 figures, 6 tables.
Multidata remote sensing approach to regional geologic mapping in Venezuela
Baker, R.N.
Remote Sensing played an important role in evaluating the exploration potential of selected lease blocks in Venezuela. Data sets used ranged from regional Landsat and airborne radar (SLAR) surveys to high-quality cloud-free air photos for local but largely inaccessible terrains. The resulting data base provided a framework for the conventional analyses of surface and subsurface information available to the project team. (1) Regional surface geology and major structural elements were interpreted from Landsat MSS imagery supplemented by TM and a regional 1:250,000 airborne radar (SLAR) survey. Evidence of dextral offset, en echelon folds and major thoroughgoing faults suggest a regional transpressional system modified by local extension and readjustment between small-scale crustal blocks. Surface expression of the major structural elements diminishes to the east, but can often be extended beneath the coastal plain by drainage anomalies and subtle geomorphic trends. (2) Environmental conditions were mapped using the high resolution airborne radar images which were used to relate vegetation types to surface texture and elevation; wetlands, outcrop and cultural features to image brightness. Additional work using multispectral TM or SPOT imagery is planned to more accurately define environmental conditions and provide a baseline for monitoring future trends. (3) Offshore oil seeps were detected using ERS-1 satellite radar (SAR) and known seeps in the Gulf of Paria as analogs. While partially successful, natural surfactants, wind shadow and a surprising variety of other phenomena created {open_quotes}false alarms{close_quotes} which required other supporting data and field sampling to verify the results. Key elements of the remote sensing analyses will be incorporated into a comprehensive geographic information (GIS) which will eventually include all of Venezuela.
Surname frequency and the isonymy structure of Venezuela.
Rodríguez-Larralde, Alvaro; Morales, Jorge; Barrai, Italo
Isonymy in Venezuela was studied analyzing the surnames of 3.9 million adults 40 years and older, selected from the register of electors updated in 1991. The electors were not differentiated by sex and represented all 22 states of Venezuela and its Federal District. The states of Nueva Esparta, an island, and Mérida, in the Venezuelan Andes, have the highest coefficients of microdifferentiation (R(ST)) and of inbreeding due to random isonymy. The states of Miranda, Aragua, Carabobo, and the Federal District, which includes the capital, Caracas, or are very close to it, had the lowest R(ST) values. The weighted averages of Fisher's alpha, a measure of surname abundance, varied by state from 43 in Nueva Esparta to 226 in Miranda, with a value of 210 for the entire country, much smaller than those observed in Switzerland, Germany, or Italy (2,396, 2,855, and 5,855, respectively). The fact that 32% of the total Venezuelan sample has only 40 surnames easily accounts for this small alpha. The correlation between the Euclidean distance and the log of geographic distance between the capital cities of states in km is high and significant (r = 0.78). The dendrogram built with the Euclidean distance matrix indicates the presence of three main clusters. One is formed by 10 states located in the western-central part of the country. The states of Zulia and Falcón join this cluster at a distance of 0.54 Euclidean units. A second cluster is formed by Barinas and the three Andean states. After combining these two, a third cluster joins them, formed by six Eastern states. Finally, the state of Amazonas enters the dendrogram at a distance of 0.66 units. Am. J. Hum. Biol. 12:352-362, 2000. Copyright 2000 Wiley-Liss, Inc. PMID:11534025
Venezuela 2000 restructures its electric power sector to ensure competitiveness
Alvarez, C.E.
Today, it is well known that the countries that are best equipped to develop their production are not those with the most natural resources but those who have the best trained people, most technical resources and that base their development on competitiveness. The State model is, definitely, not one that offers the greatest advantages, and Venezuela is an example of this. Even when, thanks to the economic boom the country enjoyed in the 70s and 80s, it was able to cost the investments required to develop its infrastructure and to prepare a first class human contingent, over the long term, competition was discouraged and waste encouraged. The result was that, even when Venezuela had vast economic resources compared to its relatively small population, it was not able to become the exception to the rule and succeed in applying this model--now considered obsolete in many countries--indefinitely. Another model based on private ownership has begun to take its place, one that has made it possible to cost the increasingly large investments required, involves opening up these sectors to private capital, and uses the phenomenon of globalization--a major driving force behind competition and one that has wrought considerable change in all corners of the increasingly smaller planet. This paper describes the steps that different sectors in the country have been taking to implement this new model in the electric power sector, such as developing draft legislation for regulating the Sector, very shortly to culminate in the passing of an electric power law by Congress; opening up the Sector to private investors (privatization); dividing the electric power industry into four business units (generation, transmission, distribution and marketing); the electric power market; and other innovations currently being implemented.
75 FR 55323 - Alta Wind Holdings, LLC; Notice of Petition for Declaratory Order
Federal Register 2010, 2011, 2012, 2013, 2014
... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Alta Wind Holdings, LLC; Notice of Petition for Declaratory Order September 2, 2010. Take notice that on August 31, 2010, Alta Wind Holdings, LLC filed a Petition...
75 FR 76455 - Alta Wind I, LLC; Notice of Petition for Declaratory Order
Federal Register 2010, 2011, 2012, 2013, 2014
... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Alta Wind I, LLC; Notice of Petition for Declaratory Order December 1, 2010. Take notice that on November 19, 2010, Alta Wind I, LLC filed a Petition for Declaratory...
The importance of trenching in paleoseismic studies in Venezuela: brief historical summary
NASA Astrophysics Data System (ADS)
Murria, J.
Paleoseismic studies have proved to be a powerful tool in seismic hazards assessment by he contributing to asses the seismogenic potential of a given fault by expanding the time window o seismic activity beyond the limits of historical and instrumental seismicity. Trenching has been an essential tool for paleoseismic studies in Venezuela. The first paleoseismic trenching project in Venezuela goes back to 1968 when Compania Shell de Venezuela retained the services of Woodward Clyde and Associates,(WCA), USA to asses the seismic integrity of the earthen dikes of Costa Oriental of Lake Maracaibo Protection System (COLM) in western Venezuela. The study was carried out under the general coordination of this author. An important part of this project included a seismology and seismic geology study under the direction of Geologist L.S. Cluff. This was the first ever study undertaken in Venezuela and included two excavations across the Oca Fault north of the city of Maracaibo. After several years of inactivity, FUNVISIS (The Venezuelan Foundation for Seismological Research) carried out in 1980 a seismic hazard (SHA) for the Uribante Caparo Hydroelectric Project southwest Venezuela. In 1989, MARAVEN, an operating company of PETROLE0S DE VENEUELA S.A. (PDVSA) undertook the project of a products pipeline form Maracaibo to El Vigia, south of Lake Maracaibo. Again, FUNVISIS was contracted to carry out a SHA, which included the digging of 5 trenches, which were supplemented with five more trenches for the COLM project. Trenching activity contined in Venezuela in the framework of SHA project, under the direction of Dr. Audemard. In 2001 Venezuelan trenching experience was exported to the neighboring Colombia as e Dr. Audemard t undertook a palaoseismicity project which included the digging of five trenches. In conclusion, paleoseismicty studies have given us the possibility of extending the scope of both instrumental and historical seismicity by some 10,000 years, trenching has
Modelo Crosscultural de Pasantias para Lideres de la Educacion: Cooperacion entre Estados Unidos y Venezuela (Designing an Effective School Administrator Internship Program: United States and Venezuela Cooperation).
ERIC Educational Resources Information Center
Serafin, Ana Gil; Thompson, Eugene W.
A model was developed of an internship program designed to give valuable cross-cultural experience to school administrators in training at universities in the United States and Venezuela. A naturalistic approach was used to develop the model. Leading school administrators and educational leadership theorists in both countries were interviewed by…
Structural Model of the Tucupita Field, Eastern Venezuela Basin
NASA Astrophysics Data System (ADS)
Arteaga, L. A.
The Tucupita Field has an area of 73,51 Km2, is located between the states of Monagas and Delta Amacuro, geologically is located at the greater Temblador area in the Eastern Venezuela Basin, where the Oficina Formation's sands represent the main hydrocarbons reservoirs. From the results of the seismic reprocessing realized by Fusion Petroleum Technologies, Inc., the structural model of this field was done as initial step to the geocellular model of the Oficina-40 Reservoir, which was defined as a Faulted Relay Ramp, where the normal faults are dominant with NE-SW orientation Introduction The Tucupita Field is a mature oilfield at the greater Temblador area, however most of the wells were completed in the upper sands, therefore the main study is focused in the geological characterization of the Oficina-40 Reservoir's lower sands, starting by the structural model Previous Studies 1. Proyecto Tucupita 3D The seismic data of the Tucupita Field were adquired in 1996 by Western Atlas of Venezuela for the Benton Vinccler Company. The UTM coordinates of the wells used in this project, have been taken to make this geological model 2. Soporte Geofísico Integrado The seismic project Tucupita was processed by Fusion Petroleum Technologies Inc., in Houston and consisted of reprocessing and pre-stack migration in time (PSTM) and pre-stack migration in depth (PSDM), this data belong to the Petrodelta Company Based on the regional stratigraphy, were validated the "picks" to make the structural sections to support research with hard data. After, it proceeded to interpret the structural style of the field from the seismic amplitude cube. Then, it was done the faults modelling and the stratigraphic horizons to carry out the geocellular model Three structural sections were realized, which was interpreted like a faulted monocline, whose peak is located southward, where justly the wells are located. The contact oil-water was interpreted to -5648'. Echelon faults were interpreted in a
Mapa Geologico de Venezuela a Escala 1:750,000
Hackley, Paul C.; Urbani, Franco; Karlsen, Alex W.; Garrity, Christopher P.
Se presenta un mapa geologico digital de Venezuela sobre un fondo de relieve sombreado. Los datos geologicos e hidrologicos del norte del rio Orinoco proceden de la digitalizacion de mapas geologicos en papel a escala 1:500.000. Estos datos fueron integrados con el mapa geologico digital del Escudo de Guayana Venezolano, a su vez derivado de hojas en papel a escala 1:500.000. La informacion sobre los tipos de fallas mostrados en el mapa es igual que en las fuentes originales. Los poligonos geologicos fueron atribuidos por edad, litologia y nombre de la unidad siguiendo el Codigo geologico de Venezuela. Se incorporaron revisiones significativas de la geologia de la Cordillera de la Costa a partir de las nuevas hojas integradas a escala 1:25.000. Toda esta informacion geologico-estructural se sobrepuso a una imagen de relieve sombreado, producida por el procesamiento de los datos de radar interferometrico con 90 m (3 arcosegundos) de resolucion espacial obtenidos por la mision topografica de radar del transbordador espacial (SRTM). Las areas de la base de datos del SRTM carentes de informacion fueron llenadas por medio de la interpolacion de los datos de las celdas adyacentes. Para producir la imagen de relieve sombreado se uso una direccion de iluminacion de 315 deg con un angulo de 65 deg sobre el horizonte. La proyeccion usada en el mapa es conica equidistante, con latitudes de 4 y 9 deg norte como paralelos estandar y una longitud de 66 deg al oeste como meridiano central. Los datos en el mapa proceden primordialment de hojas a escala 1:500.000 y el producto esta preparado para una impresion optima en escala 1:750.000. Los usuarios pueden obtener ampliaciones mayores, sin embargo no se garantiza la precision del mapa a escalas mas detalladas. Especialmente en la region de Guayana, al sobreponer los mapas geologicos sobre la reciente imagen SRTM, se notan grandes discrepancias no sistematicas tanto en contactos como en fallas. Esto es debido a que los mapas
Fluorescence Time-lapse Imaging of the Complete S. venezuelae Life Cycle Using a Microfluidic Device
Schlimpert, Susan; Flärdh, Klas; Buttner, Mark
Live-cell imaging of biological processes at the single cell level has been instrumental to our current understanding of the subcellular organization of bacterial cells. However, the application of time-lapse microscopy to study the cell biological processes underpinning development in the sporulating filamentous bacteria Streptomyces has been hampered by technical difficulties. Here we present a protocol to overcome these limitations by growing the new model species, Streptomyces venezuelae, in a commercially available microfluidic device which is connected to an inverted fluorescence widefield microscope. Unlike the classical model species, Streptomyces coelicolor, S. venezuelae sporulates in liquid, allowing the application of microfluidic growth chambers to cultivate and microscopically monitor the cellular development and differentiation of S. venezuelae over long time periods. In addition to monitoring morphological changes, the spatio-temporal distribution of fluorescently labeled target proteins can also be visualized by time-lapse microscopy. Moreover, the microfluidic platform offers the experimental flexibility to exchange the culture medium, which is used in the detailed protocol to stimulate sporulation of S. venezuelae in the microfluidic chamber. Images of the entire S. venezuelae life cycle are acquired at specific intervals and processed in the open-source software Fiji to produce movies of the recorded time-series. PMID:26967231
Fluorescence Time-lapse Imaging of the Complete S. venezuelae Life Cycle Using a Microfluidic Device.
Schlimpert, Susan; Flärdh, Klas; Buttner, Mark
Live-cell imaging of biological processes at the single cell level has been instrumental to our current understanding of the subcellular organization of bacterial cells. However, the application of time-lapse microscopy to study the cell biological processes underpinning development in the sporulating filamentous bacteria Streptomyces has been hampered by technical difficulties. Here we present a protocol to overcome these limitations by growing the new model species, Streptomyces venezuelae, in a commercially available microfluidic device which is connected to an inverted fluorescence widefield microscope. Unlike the classical model species, Streptomyces coelicolor, S. venezuelae sporulates in liquid, allowing the application of microfluidic growth chambers to cultivate and microscopically monitor the cellular development and differentiation of S. venezuelae over long time periods. In addition to monitoring morphological changes, the spatio-temporal distribution of fluorescently labeled target proteins can also be visualized by time-lapse microscopy. Moreover, the microfluidic platform offers the experimental flexibility to exchange the culture medium, which is used in the detailed protocol to stimulate sporulation of S. venezuelae in the microfluidic chamber. Images of the entire S. venezuelae life cycle are acquired at specific intervals and processed in the open-source software Fiji to produce movies of the recorded time-series. PMID:26967231
The opisthobranch gastropods (Mollusca: Heterobranchia) from Venezuela: an annotated and illustrated inventory of species.
Gutiérrez, Manuel Caballer; Ortea, Jesús; Rivero, Nelsy; Tucker, Gabriela Carias; Malaquias, Manuel António E; Narciso, Samuel
The Caribbean waters of Venezuela are composed by a large variety of habitats, with over 2800 km of coastline, islands, and islets. This area is a transitional zone between two main biogeographic provinces, the Caribbean and the Brazilian, separated by the fresh water outflows of the Orinoco and Amazon rivers, and is therefore expected to be an area of high species diversity. However, concerning the study of molluscs, Venezuela is probably the poorest known region in the Caribbean. The best compilation of opisthobranch species known in Venezuela was produced almost a decade ago, mentioning the occurrence of 57 species, plus seven determined only to genus level. In this work, 134 species are reported for Venezuela (71 are illustrated), representing about 40 % of the entire diversity of opisthobranchs known in the Caribbean. Among the species occurring in Venezuela, 49 have here the southern limit of their distribution range and only one the northern limit. Forty-six species are recorded for the first time to the country and one is a new record for the Caribbean Sea, namely Placida cremoniana. In addition, the distribution and ecology of the species are given based in literature and new data. PMID:26624440
Hydrocarbon generation and migration modeling, eastern Venezuela basin
Chigne, N.; Russomanno, F.; Sanchez, H.
The Eastern Venezuela Basin, with an area of approximately 180,000 km{sup 2}, contains important giant oil fields as well as large unexplored areas. In this region has been identified clearly all the elements of a huge Petroleum System which was kinematically modeled in time and space, following the Basin Modeling method. A passive margin originated during the Cretaceous and early Tertiary epochs, followed by emplacement of allochthonous thrust sheets coming from the west and development of a foreland basin. Therefore, thrusting, basin formation and structures are progressively younger (Oligocene to Middle Miocene) from west to east. Heat flow has increased during the Tertiary to Recent epochs from 40 to 100 mW/m{sup 2}, only in the north-central part of the basin, as interpreted from present maturity data. The first stage of oil generation occurred during late Eocene and Early Oligocene in the northernmost part of the basin. Most of oil migrated more than 150 km southernward up the undeformed homocline of the passive margin. Thus forming the Orinoco Oil Belt. Younger kitchens were later formed from north to south during Early Miocene to Recent. Oils from these kitchens were trapped by increasing tectonic deformation before reaching the southern border of the basin. Light and medium gravity oil fields were discovered in this tectonically complex area. This study has helped assess the hydrocarbon potential of as yet unexplored areas, by taking into account important quantitative factors previously not considered.
Intestinal Parasitic Infections among Pregnant Women in Venezuela
Rodríguez-Morales, Alfonso J.; Barbella, Rosa A.; Case, Cynthia; Arria, Melissa; Ravelo, Marisela; Perez, Henry; Urdaneta, Oscar; Gervasio, Gloria; Rubio, Nestor; Maldonado, Andrea; Aguilera, Ymora; Viloria, Anna; Blanco, Juan J.; Colina, Magdary; Hernández, Elizabeth; Araujo, Elianet; Cabaniel, Gilberto; Benitez, Jesús; Rifakis, Pedro
Introduction. Intestinal parasitic infections, especially due to helminths, increase anemia in pregnant women. The results of this are low pregnancy weight gain and IUGR, followed by LBW, with its associated greater risks of infection and higher perinatal mortality rates. For these reasons, in the setting of no large previous studies in Venezuela about this problem, a national multicentric study was conducted. Methods. Pregnant women from nine states were studied, a prenatal evaluation with a coproparasitological study. Univariated and multivariated analyses were made to determine risk factors for intestinal parasitosis and related anemia. Results. During 19 months, 1038 pregnant women were included and evaluated. Intestinal parasitosis was evidenced in 73.9%: A lumbricoides 57.0%, T trichiura 36.0%, G lamblia 14.1%, E hystolitica 12.0%, N americanus 8.1%, E vermicularis 6.3%, S stercoralis 3.3%. Relative risk for anemia in those women with intestinal parasitosis was 2.56 (P < .01). Discussion. Intestinal parasitoses could be associated with conditions for development of anemia at pregnancy. These features reflect the need of routine coproparasitological study among pregnant women in rural and endemic zones for intestinal parasites. Further therapeutic and prophylactic protocols are needed. Additional research on pregnant intestinal parasitic infection impact on newborn health is also considered. PMID:17093349
Gran Sabana fires (SE Venezuela): a paleoecological perspective
NASA Astrophysics Data System (ADS)
Montoya, Encarni; Rull, Valentí
Fires are among the most important risks for tropical ecosystems in a future climatic change scenario. Recently, paleoecological research has been addressed to discern the role played by fire in neotropical landscapes. However, given the magnitude of the Neotropics, many studies are relegated to infer just local trends. Here we present the compilation of the paleo-fire records developed until now in the southern Gran Sabana (SE Venezuela) with the aim to describe the fire history as well as to infer the possible forcing factors implied. In this sense, southern Gran Sabana has been under fire perturbation since the Lateglacial, with the concomitant effects upon vegetation, and persisted during the Holocene. Around 2000 cal yr BP onwards, the fire activity highly increased promoting the expansion of pre-existing savannas, the decrease of forests and the appearance and establishment of Mauritia palm swamps. The continuous fire incidence registered for several thousands of years has likely promoted the supremacy of treeless savannas upon other vegetation types and the degradation to secondary landscapes. Based on the available evidence, the anthropogenic nature of this high fire activity has been postulated. If so, it could be hypothesized that the timing arrival of Pemón, the present-day indigenous culture in the Gran Sabana, would be ca 2000 cal yr BP onwards, rather than the last centuries, as it has been formerly assumed. The implications of these ancient practices in the area are also discussed for present Gran Sabana landscapes sustainability and future conservation strategies.
Chemostratigraphy: Applications in the Tachira depression, Tachira State, Venezuela
Briceno, H.; Ostos, M.; Yoris, F.
Rock analyses (40 chemical parameters) from densely sampled Cretaceous sections from La Luna, Navay, Aguardiente and Escandalosa formations in southwestern Venezuela, combined with multivariate statistical analysis, allowed statistical characterization of formations, environmentally meaningful clustering of correlated geochemical variables, as well as calculation of chemical accumulation rates. Chemofacies, defined from accumulation rates, were used for correlation and depositional environment definition. Organic matter maturity does not affect NiN ratios, but causes homogenization in Ca/Sr ratios. Th/V ratios clearly separate shelf vs. oceanic fades, closely matching those from biofacies analysis. Cycles in Th/V repeat every 60 in (Navay) to 20 in (La Luna), corresponding to Milankovitch climatic cycles. Shales (high Th/V) represent cooler-shallower sedimentation periods, and lodestones (low Th/V) represent warmer-deeper ones. Differences in accumulation rates were used for establishing changes in: source rock (La-Ce), either due to tectonism or variations in marine current pattern; redox conditions (Ni-V); clay mineralogy (Al-K); energy level (Al-Si); and salinity (Mg-Na). Finally, chemostratigraphy, combined with reliable structural and stratigraphical field data, has proven to be a powerful tool for unravelling tectono-stratigraphical histories.
Confronting Health Disparities: Latin American Social Medicine in Venezuela
Mantini-Briggs, Clara
Objectives. We explored the emergence and effectiveness of Venezuela's Misión Barrio Adentro, "Inside the Neighborhood Mission," a program designed to improve access to health care among underserved residents of the country, hoping to draw lessons to apply to future attempts to address acute health disparities. Methods. We conducted our study in 3 capital-region neighborhoods, 2 small cities, and 2 rural areas, combining systematic observations with interviews of 221 residents, 41 health professionals, and 28 government officials. We surveyed 177 female and 91 male heads of household. Results. Interviews suggested that Misión Barrio Adentro emerged from creative interactions between policymakers, clinicians, community workers, and residents, adopting flexible, problem-solving strategies. In addition, data indicated that egalitarian physician–patient relationships and the direct involvement of local health committees overcame distrust and generated popular support for the program. Media and opposition antagonism complicated physicians' lives and clinical practices but heightened the program's visibility. Conclusions. Top-down and bottom-up efforts are less effective than "horizontal" collaborations between professionals and residents in underserved communities. Direct, local involvement can generate creative and dynamic efforts to address acute health disparities in these areas. PMID:19150916
Mitochondrial sequence variation in the Guahibo Amerindian population from Venezuela.
Vona, Giuseppe; Falchi, Alessandra; Moral, Pedro; Calò, Carla M; Varesi, Laurent
New data were obtained on mitochondrial DNA (mtDNA) from Guahibo from Venezuela, a group so far not studied using molecular data. A population sample (n = 59) was analyzed for mtDNA variation in two control-region hypervariable segments (HV1 and HV2) by sequencing. The presence or absence of a 9-bp polymorphism in the COII/tRNA(Lys) region was studied by direct amplification and electrophoretic identification. Thirty-eight variable sites were detected in regions HV1 and HV2, defining 26 mtDNA lineages; 23.7% of these were present in a single individual. The 9-bp deletion was found in 3.39% of individuals. Nucleotide and haplotype diversities were relatively high compared with other New World populations. The identified sequence haplotypes were classified into four major haplogroups (A-D) according to previous studies, with high frequencies for A (47.46%) and C (49.15%), low frequency for B (3.39%), and an absence of D. PMID:15558610
Production of a Sporulation Pigment by Streptomyces venezuelae
Scribner, H. E.; Tang, Terry; Bradley, S. G.
Streptomyces venezuelae S13 produced a pH-indicating sporulation pigment on a glucose-salts-agar medium consisting of glucose, KNO3, MgSO4, and Na2HPO4, pH 7. Pigmentation on this medium appeared to be closely associated with sporulation, which normally required 5 to 7 days at 30 C. The pigment was soluble in water as well as in a number of organic solvents. Butanol-extracted pigment exhibited absorption maxima at 430 and 520 nm at pH 3 and 12, respectively. Although many salts of organic acids and amino acids could replace glucose as the sole carbon source in basal salts-agar medium for growth and pigmentation, most sugars that were tested supported good growth but negligible pigmentation. Among the nitrogenous substances tested, KNO3 was most desirable for pigmentation. The organism did not exhibit any specific requirements for divalent cations with respect to growth and pigmentation. In the absence of MgSO4, however, glucose-salts-agar prepared by autoclaving all components together failed to support growth. The production of the sporulation pigment on glucose-salts-agar was comparable to that obtained on tomato paste-oatmeal-agar medium. Incorporation of partially purified pigment material into broth medium that did not normally support sporulation induced sporulation, and amino acid-salts-agar medium could induce vegetative mycelia to pigment when transferred from medium that did not support either pigmentation or sporulation. Images PMID:4577487
[Human ehrlichiosis: report of the 1st case in Venezuela].
Arraga-Alvarado, C; Montero-Ojeda, M; Bernardoni, A; Anderson, B E; Parra, O
Human ehrlichiosis is a zoonotic disease, caused by a rickettsia that infects leukocytes. It was described for the first time in the United States of America in 1986. More than 300 cases have been reported in that country. One case has been reported in Portugal, two in France and one more in a tourist coming from Mali (Africa). In Venezuela, a tropical country, where ehrlichiosis is endemic in dogs and horses, the first case of human ehrlichiosis is reported in a seventeen month old girl. She initially had symptoms compatible with a viral illness. Then she developed a rash, acute respiratory failure, hepato-splenomegaly, neurologic abnormalities, renal failure and hematologic alterations including pancytopenia and disseminated intravascular coagulation (DIC). Different diagnoses were given before it was concluded that it was a case of ehrlichiosis. She was treated with tetracycline and very soon recovered. The initial diagnosis was made using buffy coat blood smears stained with Diff Quick Stain. Indirect Immunofluorescence (IFA) test was used to detect antibodies against Ehrlichia chaffeensis (1:126) but not to other rickettsias. Also the presence of platelets with ehrlichia bodies similar to E. platys from dogs, it was demonstrated, in peripheral blood from the child. The presence of these bodies in human platelets has not been previously reported. In this case, it could not be proved that the disease was transmitted by a tick bite. The presence of ehrlichia bodies in platelets from the girl's peripheral blood is also described. PMID:8920030
Late quaternary environmental history of Lake Valencia, Venezuela
Platt, Bradbury J.; Leyden, B.; Salgado-Labouriau, M.; Lewis, W.M., Jr.; Schubert, C.; Binford, M.W.; Frey, D.G.; Whitehead, D.R.; Weibezahn, F.H.
Chemical, paleontological, and mineralogical analyses of a 7.5-meter core from the middle of Lake Valencia, Venezuela, have provided information on the paleoclimatic history of this low-elevation, low-latitude site for the last 13,000 years. The data show that dry climates existed in this region from 13,000 years before present (B.P.) until about 10,000 years B.P. The Lake Valencia Basin was occupied by intermittent saline marshes at that time. About 10,000 years B.P., a permanent lake of fluctuating salinity formed and arboreal plant communities replaced the earlier dominant xeric herbaceous vegetation and marsh plants. By 8500 years B.P., Lake Valencia reached moderate to low salinities and discharged water; the modern vegetation became established at that time. After 8500 years B.P., the lake twice ceased discharging as a result of reduced watershed moisture. The second of these drying episodes is still in progress and has been aggravated by human activities in the watershed. Copyright ?? 1981 AAAS.
Sedimentary sequence evolution in a Foredeep basin: Eastern Venezuela
Bejarano, C.; Funes, D.; Sarzalho, S.; Audemard, F.; Flores, G.
Well log-seismic sequence stratigraphy analysis in the Eastern Venezuela Foreland Basin leads to study of the evolution of sedimentary sequences onto the Cretaceous-Paleocene passive margin. This basin comprises two different foredeep sub-basins: The Guarico subbasin to the west, older, and the Maturin sub-basin to the east, younger. A foredeep switching between these two sub-basins is observed at 12.5 m.y. Seismic interpretation and well log sections across the study area show sedimentary sequences with transgressive sands and coastal onlaps to the east-southeast for the Guarico sub-basin, as well as truncations below the switching sequence (12.5 m.y.), and the Maturin sub-basin shows apparent coastal onlaps to the west-northwest, as well as a marine onlap (deeper water) in the west, where it starts to establish. Sequence stratigraphy analysis of these sequences with well logs allowed the study of the evolution of stratigraphic section from Paleocene to middle Miocene (68.0-12.0 m.y.). On the basis of well log patterns, the sequences were divided in regressive-transgressive-regressive sedimentary cycles caused by changes in relative sea level. Facies distributions were analyzed and the sequences were divided into simple sequences or sub- sequences of a greater frequencies than third order depositional sequences.
New Insights into Chloramphenicol Biosynthesis in Streptomyces venezuelae ATCC 10712
Fernández-Martínez, Lorena T.; Borsetto, Chiara; Gomez-Escribano, Juan Pablo; Bibb, Maureen J.; Al-Bassam, Mahmoud M.; Chandra, Govind
Comparative genome analysis revealed seven uncharacterized genes, sven0909 to sven0915, adjacent to the previously identified chloramphenicol biosynthetic gene cluster (sven0916–sven0928) of Streptomyces venezuelae strain ATCC 10712 that was absent in a closely related Streptomyces strain that does not produce chloramphenicol. Transcriptional analysis suggested that three of these genes might be involved in chloramphenicol production, a prediction confirmed by the construction of deletion mutants. These three genes encode a cluster-associated transcriptional activator (Sven0913), a phosphopantetheinyl transferase (Sven0914), and a Na+/H+ antiporter (Sven0915). Bioinformatic analysis also revealed the presence of a previously undetected gene, sven0925, embedded within the chloramphenicol biosynthetic gene cluster that appears to encode an acyl carrier protein, bringing the number of new genes likely to be involved in chloramphenicol production to four. Microarray experiments and synteny comparisons also suggest that sven0929 is part of the biosynthetic gene cluster. This has allowed us to propose an updated and revised version of the chloramphenicol biosynthetic pathway. PMID:25267678
Hemosporidian parasites in forest birds from Venezuela: genetic lineage analyses.
Mijares, Alfredo; Rosales, Romel; Silva-Iturriza, Adriana
Avian hemosporidian parasites of the genera Haemoproteus, Plasmodium, and Leucocytozoon are transmitted by different dipteran vectors. In the present work, we looked for the presence of these parasites in 47 birds from 12 families, which were sampled in the migratory corridor Paso de Portachuelo, located at the Henri Pittier National Park, Venezuela. The presence of the parasites was evidenced by amplification of a region of 471 bp of their cytochrome b gene. This region of the marker presents enough polymorphism to identify most of the mitochondrial lineages. Therefore, the obtained amplicons were sequenced, not only to identify the genus of the parasites sampled, but also to analyze their genetic diversity in the study area. The overall parasite prevalence was low (11%). We reported, for the first time, Plasmodium in birds of the species Formicarius analis and Chamaeza campanisona (Formicariidae) and Haemoproteus in Geotrygon linearis (Columbidae). A phylogenetic tree was generated using the Haemoproteus, Plasmodium, and Leucocytozoon sequences obtained in this study, together with representative sequences from previous studies. The highest genetic diversities between the two Haemoproteus lineages (11.70%) and among the three Plasmodium lineages (7.86%) found in this study are also similar to those found when lineages reported in the literature were used. These results indicate that in the migratory corridor Paso de Portachuleo, representative parasite lineages are found, making this location an attractive location for future studies. PMID:23050478
Caribbean basin framework, 4: Maracaibo basin, northwestern Venezuela
Lugo, J. )
The Maracaibo basin is presently located in a topographic depression on the Maracaibo block, a triangular, fault-bounded block within the Caribbean-South America plate boundary of northwestern Venezuela. Intense oil exploration over the last 50 years has produced a large amount of seismic and well data that can be used to constrain four Jurassic to Recent tectonic and depositional events that affected the region: (1). Late Jurassic rift phase and subsidence along normal faults striking north-northeast across the floor of the basin; (2) Cretaceous to early Eocene subsidence recorded by shallow to deep marine carbonate and clastic rocks that thicken from south to north and completely cover Permian rocks of the Merida arch; (3) Eocene folding, thrusting, and initial reactivation of Jurassic normal faults as convergent strike-slip and reverse faults. Eocene clastic sediments are thickest in a narrow northwest-trending foredeep on the northeastern margin of the basin; (4) Late Miocene to Recent northwest-southeast convergence is marked by continued reactivation of Jurassic normal faults as reverse and left-lateral strike-slip faults, uplift of mountain ranges bordering the basin, and deposition of up to 10 km of clastic sediment.
Cretaceous to Eocene passive margin sedimentation in Northeastern Venezuela
Erikson, J.P. )
Twenty two palinspastic paleogeographic maps are presented for the Cretaceous to Eocene strata of the Serrania del Interior of northeastern Venezuela. The mapped lithologies, environmental conditions, and evolving depositional systems record [approximately]90 m.y. of dominantly marine sedimentation on the only observable Mesozoic passive margin in the Western Hemisphere. The depositional systems of the passive margin are heterogeneous at lateral (i.e., along-margin) length scales greater than [approximately]40 km. The primary lateral heterogeneity is caused by a major Lower Cretaceous deltaic system that emanated southwest of the Serrania del Interior. All important intervals, such as the laterally variable Aptian-Albian El Cantil platform limestone and the hydrocarbon source rocks of the Upper Cretaceous Querecual and San Antonio formations, are related to probable causal mechanisms and environmental conditions. Stratigraphic events have been interpreted as of either local or regional extent; based on a combination of outcrop sedimentologic analyses and regional depositional systems interpretation. The 3-dimensional distribution of depositional systems and systems tracts reveals 4-6 regional sequence boundaries separated by 4-20 m.y. Subsidence analyses support the facies interpretation of a passive margin by showing continuous, thermally dominated subsidence during the Cretaceous to Eocene interval. Subsidence and accumulation rates increased and facies changed significantly in the Oligocene, indicating the end of passive margin sedimentation and the initiation of foredeep subsidence and accumulation associated with overthrusting the eastward-advancing Caribbean Plate.
A modern look at the petroleum geology of the Maracaibo basin, Venezuela
Stauffer, K.W.; Croft, G.D.
The Maracaibo basin of western Venezuela is one of the world`s most important oil producing basins, with a cumulative production of more than 35 billion bbl. The reasons for this great wealth of hydrocarbons are a combination of source beds of excellent quality, thick reservoirs with high porosity and permeability, and a series of sealing shales, faults, and unconformities, which provide large and numerous traps. Recent discoveries combined with Venezuela`s opening to international investment suggest that the story of this basin is far from over. Surprisingly little exploration has taken place in large parts of the basin, especially southwest of Lake Maracaibo and in the southern part of the lake. This paper describes the history of the basin, stratigraphy, structure, oil fields, and its future prospects.
A new cytotype of Anopheles nuneztovari from western Venezuela and Colombia.
Conn, J; Puertas, Y R; Seawright, J A
Cytogenetic analysis of the larval polytene chromosomes of Anopheles nuneztovari from 5 collection sites in Táchira and Zulia states northwest of the Andean Cordillera in western Venezuela and from 2 sites in the Department of Valle, western Colombia, revealed what appears to be a distinctive cytotype informally designated as An. nuneztovari C. Its chromosomes are homosequential with those of An. nuneztovari B from western Venezuela southeast of the Cordillera but differ in the presence of a well-defined chromocenter and unique inversion polymorphisms. The large complex inversion in western Venezuela, 2Lb, is present at a frequency of 0.263 and deviates significantly from Hardy-Weinberg equilibrium in 3 of the 5 sites. Two smaller inversions (2Lc and 2Ld) that are included in 2Lb are present in the Colombian samples at a frequency of 0.300. PMID:8245938
STSHV a teleinformatic system for historic seismology in Venezuela
NASA Astrophysics Data System (ADS)
Choy, J. E.; Palme, C.; Altez, R.; Aranguren, R.; Guada, C.; Silva, J.
From 1997 on, when the first "Jornadas Venezolanas de Sismicidad Historica" took place, a big interest awoke in Venezuela to organize the available information related to historic earthquakes. At that moment only existed one published historic earthquake catalogue, that from Centeno Grau published the first time in 1949. That catalogue had no references about the sources of information. Other catalogues existed but they were internal reports for the petroleum companies and therefore difficult to access. In 2000 Grases et al reedited the Centeno-Grau catalogue, it ended up in a new, very complete catalogue with all the sources well referenced and updated. The next step to organize historic seismicity data was, from 2004 to 2008, the creation of the STSHV (Sistema de teleinformacion de Sismologia Historica Venezolana, http://sismicidad.hacer.ula.ve ). The idea was to bring together all information about destructive historic earthquakes in Venezuela in one place in the internet so it could be accessed easily by a widespread public. There are two ways to access the system. The first one, selecting an earthquake or a list of earthquakes, and the second one, selecting an information source or a list of sources. For each earthquake there is a summary of general information and additional materials: a list with the source parameters published by different authors, a list with intensities assessed by different authors, a list of information sources, a short text summarizing the historic situation at the time of the earthquake and a list of pictures if available. There are searching facilities for the seismic events and dynamic maps can be created. The information sources are classified in: books, handwritten documents, transcription of handwritten documents, documents published in books, journals and congress memories, newspapers, seismologic catalogues and electronic sources. There are facilities to find specific documents or lists of documents with common characteristics
Lithospheric scale model of Merida Andes, Venezuela (GIAME Project)
NASA Astrophysics Data System (ADS)
Schmitz, M.; Orihuela, N. D.; Klarica, S.; Gil, E.; Levander, A.; Audemard, F. A.; Mazuera, F.; Avila, J.
Merida Andes (MA) is one of the most important orogenic belt in Venezuela and represents the northern culmination of South America Andes. During the last 60 years, several models have been proposed to explain the shallow and deep structure, using different geological, geophysical, seismological, geochemical and petrologic concepts; nevertheless, most of them have applied local observation windows, and do not represent the major structure of MA. Therefore, a multidisciplinary research group, coordinated by FUNVISIS, in close cooperation with UCV, ULA and PDVSA, is proposed in order to get the outlined goals in the project entitled GIAME ("Geociencia Integral de los Andes de MErida") was established, which aims to generate a lithospheric scale model and the development of a temporal dynamic model for the MA. As a base for lithospheric investigations of the Merida Andes, we are proposing three wide angle seismic profiles across the orogen on three representative sites, in order to determine the inner structure and its relation with the orogen's gravimetric root. To the date, there are no seismic studies at lithospheric scale which cross MA. The wide angle seismic will be complemented with the re-processing and re-interpretation of existing reflection seismic data, which will allow to establish a relationship between MA and its associated flexural basins (Maracaibo and Barinas-Apure basins). Depending on the results of the VENCORP Project (VENezuelan COntinental Reflection Profiling), which might show some reliable results about crustal features and Moho reflectors along three long seismic profiles at Caribbean Moutain system, a reflection seismic profile across the central portion of MA is proposed. Additional tasks, consisting in MA quaternary deformation studies, using research methods like neotectonics and paleoseismology, georadar, numerical modeling, cinematic GPS, SAR interferometry, thermocronology, detailed studies on regional geology, flexural modeling
A 75 ka Stalagmite Paleoclimate Record from Northern Venezuela
NASA Astrophysics Data System (ADS)
Retrum, J. B.; Gonzalez, L. A.; Edwards, R.; Tincher, S. M.; Cheng, H.; Urbani, F.
A stalagmite collected from Cueva Zarraga in the northern Venezuelan Andes was analyzed to determine local paleoclimatic history and help examine climate change in the Caribbean. Ages were determined by U/Th disequilibrium and the stalagmite shows a nearly complete record for ~ 75 ka. Two significant periods of non-deposition have been identified. The first period ranges between the Last Glacial Maximum at 19,820 ± 149 cal yr BP and a brief resumption of stalagmite growth at 15,409 ± 747 cal yr BP, likely representing the Bølling-Allerød interstadial. After the brief period of deposition, growth does not resume unil the Holocene at 10,408 ± 78 cal yr BP. Carbon and oxygen isotopes show a major depletion shift from the last glacial period to the Holocene, suggesting warmer and wetter conditions during the Holocene. The oxygen isotope depletion shift is also seen in the Cariaco Basin foraminifera record off the northern coast of Venezuela. While tempting to attribute δ13C depletion to decrease of the C4 plant contribution, there is no evidence that the area experience major vegetation changes. We attribute the δ13C depletion to enhanced recycling of soil CO2 resulting from canopy effects. Today, Cueva Zarraga is at the northern extent of the Inter-Tropical Convergence Zone (ITCZ). The cooler and drier conditions of the last glacial period suggest a southern displacement of the ITCZ. The close proximity of Cueva Zarraga to Cariaco Basin may allow for a high resolution tropical terrestrial and oceanic climatic response comparison.
Neogene history of the Carapita Formation, Eastern Venezuela basin
NASA Astrophysics Data System (ADS)
Sanchez Zambrano, Dennis Alberto
The planktonic and benthic foraminifera from the lower to middle Miocene shales of the Carapita Formation of Eastern Venezuela in three exploration wells and one outcrop section are analyzed with the objectives of establishing a precise biostratigraphy of the formation and its bathymetric history. Comparison with the well-preserved microfaunas of the correlative Cipero Formation of Trinidad made possible the achievement of these objectives. The formation, up to 4500 to 6000 m thick in outcrops, extends from northeastern Anzoategui and North of Monagas States to the Gulf of Paria and is both an important oil reservoir towards the east and the main seal rock for the Oligocene reservoir in the north of Monagas State. In the area studied the Carapita Formation spans lower to lower middle Miocene Zones N6/M3 to N9/M6; its upper part is unconstrained as only rare long ranging early Miocene to early Pliocene planktonic foraminifera occur above the Orbulina datum. Unexpectedly, we found that the four lower to middle Miocene sections are highly discontinuous, with hiastuses as long as 4 Myr. Based on the abundance patterns of sixty-nine species of benthic foraminifera and analysis of morphotype abundance following the methodology of Corliss and Chen (1988) and Corliss and Fois (1993), we show that the Carapita Formation was deposited at outer neritic to middle bathyal depths (≥200--1000 m), whereas the Cipero Formation was deposited at middle to lower bathyal depths (≥600--2000 m). Importantly, the bathymetric changes are associated with unconformities in all sections, strongly suggesting that both (shallowing and associated unconformities) were tectonically induced.
Encounters with Science at ULA, Venezuela: An Incentive for Learning
NASA Astrophysics Data System (ADS)
Rosenzweig, P.
In the School of Science of the Universidad de Los Andes (ULA), in Mérida, Venezuela, a very successful event focused on high school students and primary school students, was founded in 2000. The name of this event is "Encounters with Physics, Chemistry, Mathematics, and Biology" (hereinafter "Encounters with Science"), and it integrates these disciplines as well as Astronomy. Its main purpose is that young minds can become familiar with the methods of science inquiry and reasoning, and can understand the concepts and processes of the sciences through thoroughly prepared experiences. This flourishing program is continuing to grow and to become strong. As a matter of fact, in its sixth edition (2005), the number of high and elementary school students coming from all over the country, has reached the outstanding number of nine thousand. Among all the experiences that the students could be engaged in were many involving Astronomy. These experiences were prepared by professors, together with graduate and undergraduate students, who are pursuing their degrees in all branches of science including astronomy. Although there is this incredible team of faculties and graduate and undergraduate students working together; the target is the students of the high and elementary schools. We certainly focus on the engaging and encouraging of students to experience scientific work first hand. Additionally, our professors have prepared an excellent didactic material that can, together with the hour/class teaching, prepare high school and elementary school students for a better understanding of science; particularly, helping in this way for a better education in Astronomy. The main event of the Encounters lasts five days in the School of Science of ULA, but subsidiary events are spread all over the year and around the country. As a successful program, it can be interesting to see if other countries can adopt this method to recruit or to trigger the interest of students to pursue their
A modern regional geological analysis of Venezuela - lessons from a major new world oil province on exploration in mature areas
Daly, M. ); Audemard, F. ); Valdes, G. )
Venezuela has produced some 44 billion bbl of oil since the early part of the century. As such, it represents one of the world's major oil producers and a mature petroleum province. However, major tracts of Venezuela's sedimentary basins remain underexplored and large discoveries are still being made in new and old reservoir systems. A regional geological analysis of Venezuela, focusing on basin evolution and sequence stratigraphy and incorporating data from the three national oil companies, is presented. The analysis presents a regionally consistent tectonostratigraphic model capable of explaining the evolution of the Mesozoic and Cenozoic basins of Venezuela and placing the major reservoir facies in their regional tectonic and sequence stratigraphic context. Four regional cross sections describe the stratigraphic and structural model. The model recognizes a Jurassic rifting event and inversion, succeeded by an Early Cretaceous passive margin. In western Venezuela, the Early Cretaceous passive subsidence is enhanced locally by extension related to the Colombian active margin. Venezuela experienced a major change in the Campanian with the initial collision of the Caribbean arc, recorded by foreland structuring and widespread stratigraphic changes. From the Campanian onward, the tectonostratigraphic evolution can be modeled in terms of a progressive southeast-directed arc-continent collision and the migration of the associated foredeep and rift basins. Within the tectonic framework, the major sequence stratigraphic units are identified and the reservoir distribution interpreted. This model provides a strong predictive tool to extrapolate reservoir systems into Venezuela's underexplored areas and to readdress its traditional areas.
78 FR 13380 - Silicomanganese From India, Kazakhstan, and Venezuela; Scheduling of Full Five-Year Reviews...
Federal Register 2010, 2011, 2012, 2013, 2014
... to section 751(c)(5) of the Act should proceed (78 FR 4437, January 22, 2013). A record of the... amendments took effect on November 7, 2011. See 76 FR 61937 (Oct. 6, 2011) and the newly revised Commission's... COMMISSION Silicomanganese From India, Kazakhstan, and Venezuela; Scheduling of Full Five-Year...
Lobomycosis in Man and Lobomycosis-like Disease in Bottlenose Dolphin, Venezuela
Bermudez, Luis; Van Bressem, Marie-Françoise; Reyes-Jaimes, Oscar; Sayegh, Alejandro J.
We report 1 case of lobomycosis caused by Lacazia loboi in a fisherman and 1 case of lobomycosis-like disease in a bottlenose dolphin (Tursiops truncatus) along the coast of Venezuela. These findings suggest that the marine environment is a likely habitat for L. loboi and a reservoir for infection. PMID:19751598
Mansonella ozzardi infections in Indians of the Southwestern part of the state of Bolivar, Venezuela.
Godoy, G A; Volcan, G; Medrano, C; Teixeira, A; Matheus, L
Mansonella ozzardi infections were found in 80/139 (58%) of Indians living in the forest of the upper Caura River Basin located in the southwestern part of Bolivar State, Venezuela. In four (3%) of the blood samples a second type of microfilaria which could not be identified was also found. PMID:6992608
78 FR 49471 - Ferrosilicon From the Russian Federation and Venezuela: Initiation of Antidumping Duty...
Federal Register 2010, 2011, 2012, 2013, 2014
... antidumping duty (``AD'') petitions concerning imports of ferrosilicon from the Russian Federation (``Russia... Russia Petition'' and ``Supplement to Venezuela Petition''). On August 2, 2013, the Department spoke with... below. \\1\\ See ``Petitions for the Imposition of Antidumping Duties on Ferrosilicon from Russia...
An Innovative Project in Educational Technology: The Panama-Venezuela Project.
ERIC Educational Resources Information Center
Rojas, Alicia Mabel
Describes a project which is being implemented in the field of educational technology in Panama and Venezuela. The project emphasizes inservice training of a cadre of professionals who will direct efforts to identify and resolve significant problems in education. (Author/CHC)
The Peasantry as an Emerging Political Factor in Mexico, Bolivia, and Venezuela.
ERIC Educational Resources Information Center
Lord, Peter P.
This study examines the potential role of the peasantry in the determination of political power in Latin America. Case studies of Mexico, Bolivia, and Venezuela illustrate that the framework of political change is of major importance because it is crucial in determining the properties of the political system to follow. The previous involvement of…
78 FR 9034 - Silicomanganese From India, Kazakhstan, and Venezuela: Final Results of the Expedited Second...
Federal Register 2010, 2011, 2012, 2013, 2014
..., Kazakhstan, and Venezuela, 67 FR 36149 (May 23, 2002). On October 1, 2012, the Department initiated the... (``the Act''). See Initiation of Five-Year (``Sunset'') Review, 77 FR 59897 (October 1, 2012) (``notice... revocation of these antidumping duty orders would be likely to lead to continuation or recurrence of...
Geographic distribution and host plants of Raoiella indica and associated mite species in northern Venezuela.
Vásquez, Carlos; de Moraes, Gilberto J
The red palm mite (RPM), Raoiella indica Hirst (Acari: Tenuipalpidae), is an invasive pest in the New World, where it is currently considered a serious threat to coconut and banana crops. It was first reported from northern Venezuela in 2007. To determine its current distribution in this country, surveys were carried out from October 2008 to April 2010 on coconut (Cocos nucifera L.), banana (Musa spp.), ornamental plants and weeds in northern Venezuela. Higher population levels of RPM were registered on commercial coconut farms in Falcón and Sucre states but also on other plant species naturally growing along the coastal line in Anzoategui, Aragua, Carabobo, Monagas and Nueva Esparta states. Out of 34 botanical species evaluated, all RPM stages were observed only on eight arecaceous, one musaceous and one streliziaceous species, indicating that the pest developed and reproduced only on these plants. Mite specimens found on weeds were considered spurious events, as immature stages of the pest were never found on these. Amblyseius largoensis (Muma) (Acari: Phytoseiidae) was the most frequent predatory mite associated with RPM in all sampling sites. The results indicate that RPM has spread to extensive areas of northern Venezuela since its initial detection in Güiria, Sucre state. Considering the report of this pest mite in northern Brazil in the late 2009, additional samplings in southern Venezuela should be carried out, to evaluate the possible presence of RPM also in that region. PMID:23065034
Decentralization and Regionalization in Educational Administration: Comparisons of Venezuela, Colombia and Spain.
ERIC Educational Resources Information Center
Hanson, E. Mark
A nation's transition from dictatorship to democracy generally involves institutional reform attempts with new priorities serving a wider range of people and goals. This study describes and compares the goals, means, and outcomes of administrative reforms in the public educational systems of three Hispanic nations (Venezuela, Colombia, and Spain).…
Resurrection Symphony: "El Sistema" as Ideology in Venezuela and Los Angeles
ERIC Educational Resources Information Center
Fink, Robert
The explosive growth of Venezuela's "El Sistema" is rewriting the agenda of musical education in the West. Many commentators from the world of classical music react to the spectacle of dedicated young colonial musicians playing European masterworks as a kind of "miracle," accepting "Sistema" founder José Antonio…
The Effect of Wage Compression and Alternative Labor Market Opportunities on Teacher Quality in Venezuela
ERIC Educational Resources Information Center
Ortega, Daniel E.
This paper examines the effect of teacher relative wages and teacher wage dispersion on high school graduates' preferences for teaching majors in College. This approximation to teacher quality is appropriate in a country like Venezuela as opposed to the US since the rigidity of the tertiary school system significantly limits mobility between…
Five Years of Cyclotron Radioisotope Production Experiences at the First PET-CT in Venezuela
Colmenter, L.; Coelho, D.; Esteves, L. M.; Ruiz, N.; Morales, L.; Lugo, I.; Sajo-Bohus, L.; Liendo, J. A.; Greaves, E. D.; Barros, H.; Castillo, J.
Five years operation of a compact cyclotron installed at PET-CT facility in Caracas, Venezuela is given. Production rate of {sup 18}F labeled FDG, operation and radiation monitoring experience are included. We conclude that {sup 18}FDG CT-PET is the most effective technique for patient diagnosis.
The Bolivarian University of Venezuela: A Radical Alternative in the Global Field of Higher Education?
ERIC Educational Resources Information Center
Ivancheva, Mariya
This article discusses paradoxes in the emergent global field of higher education as reflected in an alternative model of the university--the Bolivarian University of Venezuela (UBV) and the related higher education policy, Mision Sucre. With its credo in the applied social sciences, its commitment to popular pedagogy and its dependence on…
Education, Democracy and Social Change: Venezuela's Education Missions in Theory and Practice
ERIC Educational Resources Information Center
Duffy, Maura
The "Bolivarian Revolution" in Venezuela is conceptualised as a pedagogical project that aims to develop "twenty-first century Socialism" through state-grassroots collaboration in the reorganisation of political space in order to develop participatory, democratic institutions and processes. The cornerstones of this project to…
78 FR 44969 - Ferrosilicon From Russia and Venezuela; Institution of Antidumping Duty Investigations and...
Federal Register 2010, 2011, 2012, 2013, 2014
.... Please consult the Commission's rules, as amended, 76 FR 61937 (Oct. 6, 2011) and the Commission's Handbook on Filing Procedures, 76 FR 62092 (Oct. 6, 2011), available on the Commission's Web site at http... COMMISSION Ferrosilicon From Russia and Venezuela; Institution of Antidumping Duty Investigations...
Counter-Hegemonic Regionalism and Higher Education for All: Venezuela and the ALBA
ERIC Educational Resources Information Center
Muhr, Thomas
This paper employs new regionalism theory and regulatory regionalism theory in its analysis and theorisation of the Bolivarian Alliance for the Peoples of Our America (ALBA) as a counter-hegemonic Latin American and Caribbean (LAC) regionalism. As (initially) the regionalisation of Venezuela's Bolivarian Revolution, ALBA is centred around the idea…
Comprehensive Education Bolivarian-Style: The Alternative School in Barrio Pueblo Nuevo, Venezuela
ERIC Educational Resources Information Center
Cole, Mike
In this article, the author traces revolutionary developments in an alternative school in Barrio Pueblo Nuevo, Mérida, in the Bolivarian Republic of Venezuela, a school that caters for students between 4 and 14. He begins by recounting some fieldwork done at the school on his behalf by Edward Ellis in 2010. He goes on to discuss a video made at…
Teachers' Perceived Efficacy among English as a Foreign Language Teachers in Middle Schools in Venezuela
ERIC Educational Resources Information Center
Chacon, C.T.
Teachers' sense of efficacy has been shown to influence teachers' actions and student outcomes. This study explored self-efficacy beliefs among English as a Foreign Language teachers in selected schools in Venezuela. Data were collected through a survey administered to 100 teachers. The Teacher Sense of Efficacy Scale (Tschannen-Moran & Woolfolk…
[Prevalence of human infections by Trypanosoma cruzi in blood banks in Venezuela].
Aché, A
Primary investigations carried out in blood banks in Venezuela during the 1950s, indicated that overall seroprevalence for Trypanosoma cruzi infection was 12% amongst blood donors. In Venezuela, blood donation is free. All public and private blood banks are controlled by the Ministry of Health. As from 1988 the ELISA technique was uniformly used in blood banks for the detection of T. cruzi infections. Annual median seroprevalence, between 1988 to 1992, was 1.20% (1.09-1.94%), with geographical variations between localities in several States. States with higher prevalence rates are located in the western and central part of Venezuela: Portuguesa, Lara, Trujillo, Cojedes and Carabobo. Due to difficulties in obtaining incidence rates for Chagas disease, it seems proper to use prevalence rates due to its greater stability; and in the specific case of Venezuela, due to a lesser severity and a higher survival of this disease at present. Considering that there is little to be offered to the seropositive individual, repeatability is avowed for serological diagnosis. Specificity should be strived for in the light of lower prevalence rates at present. PMID:8115813
Guidelines For Implementation of Industrial Programs For Proposed Community Colleges in Venezuela.
ERIC Educational Resources Information Center
Sada, Pablo Maria
The purpose of this study was to examine selected industrial education departments and programs of the community colleges in the United States, and to draw some beneficial implications for the establishment of the proposed community colleges in Venezuela. The procedure involved a review of the literature, the construction of a questionnaire, and…
The Universidad Nacional Abierta of Venezuela. A Case Study in Distance Learning Systems.
ERIC Educational Resources Information Center
Friedman, H. Z.
A brief description of the country of Venezuela (geography, population, economy, internal communications, and politics) and its educational system introduce a description of the Universidad Nacional Abierta (UNA). The UNA was opened in July 1978 to expand the national system of higher education by the use of distance learning techniques. These…
Rural Development in Venezuela and the Guianas: A Bibliography. Training and Methods Series Number 20.
ERIC Educational Resources Information Center
Anderson, Teresa, Comp.; And Others
The bibliography cites 930 materials dealing with Venezuela and the Guianas. Published between 1949 and 1972, the materials are found in the Land Tenure Center Library at the University of Wisconsin. Topics covered are: agriculture, agrarian reform, economic affairs, economic cooperation, human resources, American Indians, industry, law, money,…
José María Vargas (1786-1854): Reformer of anatomical studies in Venezuela.
Reverón, Rafael Romero
José María Vargas (1786-1854): Venezuelan medical doctor, surgeon, optician, anatomist, chemist, botanist, professor, geologist, mineralogist, and mathematician. Second President of Venezuela (1835-1836), First republican dean, he reformed medicine studies in 1827 establishing human anatomical dissection in the Universidad Central de Venezuela where he taught human anatomy between 1827 and 1853 along with surgery and chemistry. In 1838, he wrote Curso de Lecciones y demostraciones Anatómicas, the first book on the subject printed in Venezuela for the teaching of human anatomy. PMID:23650143
Neotropical genera of Naucoridae (Hemiptera: Heteroptera: Nepomorpha): new species of Placomerus and Procryphocricos from Guyana and Venezuela.
Sites, Robert W; Camacho, Jesús
The Neotropical fauna of saucer bugs (Naucoridae) currently includes four monotypic genera. Recent extensive collecting in Venezuela has produced three new species in two of these genera. In addition, undetermined Guyanan specimens of one of the new species were found in the United States National Museum of Natural History. Thus, described here are Placomerus obscuratus n. sp. from Guyana and Venezuela with brachypterous and macropterous hindwing forms, and two species of Procryphocricos from Venezuela. Procryphocricos quiu n. sp. is described from the brachypterous forewing form and Procryphocricos macoita n. sp. from both brachypterous and macropterous forms. Previously described species also are discussed. PMID:24869509
Seismic microzoning projects and their implementation in Venezuela
NASA Astrophysics Data System (ADS)
Schmitz, M.; Cano, V.; Olbrich, F.; Vallee, M.; Morales, C.; Arreaza, A.; Mendes, K.; Klarica, S.; Alvarez Gomez, J.; Aray, J.; Vielma, J.; Pombo, A.; Diaz, J.; Grupo de trabajo
Site effects have been recognized to play an important role in damage distribution of destructive earthquakes. These effects have been observed in Venezuela especially during the 1967 Caracas earthquake, when 4 buildings with 10 and more storeys during the Caracas 1967 earthquake collapsed, and a big number of them in the same deep sediment area have been seriously damaged. This motivated the development of studies regarding the subsurface configuration of Caracas and Barquisimeto during the last decade, with a seismic microzoning project realized in both cities from 2005 to 2009. The main results of this project were the development of design response spectra for the different microzones within the sedimentary basin, as well as estimates of landslide hazard. Implementation of the results in municipality ordinances is actually discussed with local authorities. They are aimed to address mitigation for new constructions by the application of the specific design spectra, for existing buildings via evaluation and retrofitting strategies, and for slope areas (informal, as well as formal developments) due to the identification of areas that may not be developed or require detailed studies of slope stabilities. Since then, seismic microzoning studies were started in Cumaná, Guarenas/Guatire and Lara state, and within a broader context of integrated risk management, which includes flooding, landslide and technological risks, in Mérida, Valencia, Maracay, Barcelona/Puerto La Cruz and Valle de la Pascua. The projects are coordinated by the Venezuelan Foundation for Seismological Research (FUNVISIS) in cooperation with local universities. Efforts are done to unable local researchers to apply the methodologies in other cities as Valera, Trujillo, Boconó, San Cristóbal and Tucacas. A unified seismic hazard map as input motion to these studies is actually in development. Depending on the local characteristics, building inventory and vulnerability analysis are done for risk
Holocene evolution of the western Orinoco Delta, Venezuela
Aslan, A.; White, W.A.; Warne, A.G.; Guevara, E.H.
The pristine nature of the Orinoco Delta of eastern Venezuela provides unique opportunities to study the geologic processes and environments of a major tropical delta. Remote-sensing images, shallow cores, and radiocarbon-dating of organic remains form the basis for describing deltaic environments and interpreting the Holocene history of the delta. The Orinoco Delta can be subdivided into two major sectors. The southeast sector is dominated by the Rio Grande-the principal distributary-and complex networks of anastomosing fluvial and tidal channels. The abundance of siliciclastic deposits suggests that fluvial processes such as over-bank flooding strongly influence this part of the delta. In contrast, the northwest sector is represented by few major distributaries, and overbank sedimentation is less widespread relative to the southeast sector. Peat is abundant and occurs in herbaceous and forested swamps that are individually up to 200 km2 in area. Northwest-directed littoral currents transport large volumes of suspended sediment and produce prominent mudcapes along the northwest coast. Mapping of surface sediments, vegetation, and major landforms identified four principal geomorphic systems within the western delta plain: (1) distributary channels, (2) interdistributary flood basins, (3) fluvial-marine transitional environments, and (4) marine-influenced coastal environments. Coring and radiocarbon dating of deltaic deposits show that the northern delta shoreline has prograded 20-30 km during the late Holocene sea-level highstand. Progradation has been accomplished by a combination of distributary avulsion and mudcape progradation. This style of deltaic progradation differs markedly from other deltas such as the Mississippi where distributary avulsion leads to coastal land loss, rather than shoreline progradation. The key difference is that the Orinoco Delta coastal zone receives prodigious amounts of sediment from northwest-moving littoral currents that transport
Mycobacterium tuberculosis population structure and molecular epidemiological analysis in Sucre municipality, Miranda state, Venezuela.
Patiño, Margareth A; Abadía, Edgar; Solalba Gómez; Maes, Mailis; Muñoz, Mariana; Gómez, Daniela; Guzmán, Patricia; Méndez, María Victoria; Ramirez, Carmen; Mercedes, España; de Waard, Jacobus; Takiff, Howard
Sucre municipality is a large, densely populated marginal area in the eastern part of Caracas, Venezuela that consistently has more cases of tuberculosis than other municipalities in the country. To identify the neighborhoods in the municipality with the highest prevalence of tuberculosis, and determine whether the Mycobacterium tuberculosis strain distribution in this municipality is different from that previously found in the western part of Caracas and the rest of Venezuela, we collected data on all tuberculosis cases in the municipality diagnosed in 2005-6. We performed two separate molecular epidemiological studies, spoligotyping 44 strains in a first study, and spoligotyping 131 strains, followed by MIRU-VNTR 15 on 21 clustered isolates in the second. With spoligotyping, the most common patterns were Shared International Type SIT17 (21%); SIT42 (15%); SIT93 (11%); SIT20 (7%); SIT53 (6%), a distribution similar to other parts of Venezuela, except that SIT42 and SIT20 were more common. MIRU-VNTR 15 showed that six of seven SIT17 strains examined belonged to a large cluster previously found circulating in Venezuela, but all of the SIT42 strains were related to a cluster centered in the neighborhoods of Unión and Maca, with a MIRU-VNTR pattern not previously seen in Venezuela. It appears that a large percentage of the tuberculosis in the Sucre municipality is caused by the active transmission of two strain families centered within distinct neighborhoods, one reflecting communication with the rest of the country, and the other suggesting the insular, isolated nature of some sectors. PMID:25558753
Book Review: "Educational Reform and Administrative Development: The Cases of Columbia and Venezuela," by E. Mark Hanson.
ERIC Educational Resources Information Center
Lynch, Patrick D.
Reviews "Educational Reform and Administrative Development: The Cases of Colombia and Venezuela," by E. Mark Hanson, which relates the policy-making and administrative structures of these two countries to their political, historical, and cultural contexts. (TE)
Pilot-Scale Demonstration of ALTA for NOx Control in Pulverized Coal-Fired Boilers
Andrew Fry; Devin Davis; Marc Cremer; Bradley Adams
This report describes computational fluid dynamics (CFD) modeling and pilot-scale testing conducted to demonstrate the ability of the Advanced Layered Technology Approach (ALTA) to reduce NO{sub x} emissions in a pulverized coal (PC) boiler. Testing specifically focused on characterizing NO{sub x} behavior with deep burner staging combined with Rich Reagent Injection (RRI). Tests were performed in a 4 MBtu/hr pilot-scale furnace at the University of Utah. Reaction Engineering International (REI) led the project team which included the University of Utah and Combustion Components Associates (CCA). Deep burner staging and RRI, combined with selective non-catalytic reduction (SNCR), make up the Advanced Layered Technology Approach (ALTA) for NO{sub x} reduction. The application of ALTA in a PC environment requires homogenization and rapid reaction of post-burner combustion gases and has not been successfully demonstrated in the past. Operation of the existing low-NO{sub x} burner and design and operation of an application specific ALTA burner was guided by CFD modeling conducted by REI. Parametric pilot-scale testing proved the chemistry of RRI in a PC environment with a NOx reduction of 79% at long residence times and high baseline NOx rate. At representative particle residence times, typical operation of the dual-register low-NO{sub x} burner provided an environment that was unsuitable for NO{sub x} reduction by RRI, showing no NOx reduction. With RRI, the ALTA burner was able to produce NO{sub x} emissions 20% lower than the low-NO{sub x} burner, 76 ppmv vs. 94 ppmv, at a burner stoichiometric ratio (BSR) of 0.7 and a normalized stoichiometric ratio (NSR) of 2.0. CFD modeling was used to investigate the application of RRI for NO{sub x} control on a 180 MW{sub e} wall-fired, PC boiler. A NO{sub x} reduction of 37% from baseline (normal operation) was predicted using ALTA burners with RRI to produce a NO{sub x} emission rate of 0.185 lb/MBtu at the horizontal nose of
Household energy use in urban Venezuela: Implications from surveys in Maracaibo, Valencia, Merida, and Barcelona-Puerto La Cruz
Figueroa, M.J.; Sathaye, J.
This report identifies the most important results of a comparative analysis of household commercial energy use in Venezuelan urban cities. The use of modern fuels is widespread among all cities. Cooking consumes the largest share of urban household energy use. The survey documents no use of biomass and a negligible use of kerosene for cooking. LPG, natural gas, and kerosene are the main fuels available. LPG is the fuel choice of low-income households in all cities except Maracaibo, where 40% of all households use natural gas. Electricity consumption in Venezuela`s urban households is remarkably high compared with the levels used in households in comparable Latin American countries and in households of industrialized nations which confront harsher climatic conditions and, therefore, use electricity for water and space heating. The penetration of appliances in Venezuela`s urban households is very high. The appliances available on the market are inefficient, and there are inefficient patterns of energy use among the population. Climate conditions and the urban built form all play important roles in determining the high level of energy consumption in Venezuelan urban households. It is important to acknowledge the opportunities for introducing energy efficiency and conservation in Venezuela`s residential sector, particularly given current economic and financial constraints, which may hamper the future provision of energy services.
78 FR 18972 - Alta Wind X, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for...
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... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Alta Wind X, LLC; Supplemental Notice That Initial Market-Based Rate Filing...-referenced proceeding, of Alta Wind X, LLC's application for market-based rate authority, with...
78 FR 18973 - Alta Wind XI, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for...
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77 FR 35669 - AltaGas Renewable Energy Colorado LLC; Supplemental Notice That Initial Market-Based Rate Filing...
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75 FR 57014 - Alta Wind IV, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for...
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... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Alta Wind IV, LLC; Supplemental Notice That Initial Market-Based Rate Filing... the above-referenced proceeding of Alta Wind IV, LLC's application for market-based rate...
76 FR 3881 - Application To Export Electric Energy; TransAlta Energy Marketing (U.S.) Inc.
Federal Register 2010, 2011, 2012, 2013, 2014
... Application To Export Electric Energy; TransAlta Energy Marketing (U.S.) Inc. AGENCY: Office of Electricity Delivery and Energy Reliability, DOE. ACTION: Notice of application. SUMMARY: TransAlta Energy Marketing (U... be surplus energy purchased from electric utilities, Federal power marketing agencies, and...
Carne cocinada a altas temperaturas y el riesgo de cáncer
Hoja informativa que explica cómo algunos compuestos químicos se forman en la carne cocinada a alta temperatura y describe los resultados de estudios sobre el consumo de estos compuestos químicos y el riesgo de cáncer.
Barrio Adentro and the reduction of health inequalities in Venezuela: an appraisal of the first years.
Armada, Francisco; Muntaner, Caries; Chung, Haejoo; Williams-Brennan, Leslie; Benach, Joan
This article presents an update on the characteristics and performance of Venezuela's Bolivarian health care system, Barrio Adentro (Inside the Neighborhood). During its first five years of existence, Barrio Adentro has improved access and utilization of health services by reaching approximately 17 million impoverished and middle-class citizens all over Venezuela. This was achieved in approximately two years and provides an example of an immense "South-South" cooperation and participatory democracy in health care. Popular participation was achieved with the Comités de Salud (health committees) and more recently with the Consejos Comunales (community councils), while mostly Cuban physicians provided medical care. Examination of a few epidemiological indicators for the years 2004 and 2005 of Barrio Adentro reveals the positive impact of this health care program, in particular its primary care component, Barrio Adentro I. Continued political commitment and realistic evaluations are needed to sustain and improve Barrio Adentro, especially its primary care services. PMID:19326784
Review of the Berosus Leach of Venezuela (Coleoptera, Hydrophilidae, Berosini) with description of fourteen new species
Oliva, Adriana; Short, Andrew E. Z.
Abstract The species of the water scavenger beetle genus Berosus Leach occurring in Venezuela are reviewed. Thirty-six species are recorded, including fifteen new species, fourteen of which are described here as new: Berosus aragua sp. n., Berosus asymmetricus sp. n., Berosus capanaparo sp. n., Berosus castaneus sp. n., Berosus corozo sp. n., Berosus ebeninus sp. n., Berosus garciai sp. n., Berosus humeralis sp. n., Berosus jolyi sp. n., Berosus llanensis sp. n., Berosus megaphallus sp. n., Berosus ornaticollis sp. n., Berosus repertus sp. n., and Berosus tramidrum sp. n. The fifteenth new species, known from a single female, is left undescribed pending the collection of males. Twelve species are recorded from Venezuela for the first time: Berosus ambogynus Mouchamps, Berosus consobrinus Knisch, Berosus elegans Knisch, Berosus geayi d'Orchymont, Berosus ghanicus d'Orchymont, Berosus guyanensis Queney, Berosus holdhausi Knisch, Berosus marquardti Knisch, Berosus olivae Queney, Berosus reticulatus Knisch, Berosus wintersteineri Knisch, and Berosus zimmermanni Knisch. PMID:22811607
KPC and VIM producing Enterobacter cloacae strain from a hospital in northeastern Venezuela.
Martínez, Dianny; Marcano, Daniel; Rodulfo, Hectorina; Salgado, Nurys; Cuaical, Nirvia; Rodriguez, Lucy; Caña, Luisa; Medina, Belkis; Guzman, Militza; De Donato, Marcos
An 83-year-old male patient is admitted to the central hospital in Cumana, Venezuela with severe urinary infection, history of hospitalizaions and prolonged antimicrobial treatments. A strain of Enterobacter cloacae was isolated showing resistance to multiple types of antibiotics (only sensitive to gentamicin), with phenotype of serine- and metallo-carbapenemases. Both, bla(VIM-2) and bla(KPC) genes were detected in the isolate. This is the first report of an Enterobacteriaceae species producing both KPC carbapenemase and VIM metallo carbapenemase in Venezuela. This finding has a great clinical and epidemiological impact in the region, because of the feasibility of transferring these genes, through mobile elements to other strains of Enterobacter and to other infection-causing species of bacteria. PMID:26299058
Heavy metals in green mussel (Perna viridis) and oysters (Crassostrea sp.) from Trinidad and Venezuela.
Rojas de Astudillo, L; Chang Yen, I; Agard, J; Bekele, I; Hubbard, R
Heavy metal concentrations were monitored in edible soft tissues of shellfish from Trinidad and Venezuela. Oysters (Crassostrea sp.) and the green mussel (Perna viridis), which is a recently transplanted species to the Caribbean from the Far East, were collected at six locations in Venezuela and five in Trinidad, the latter along the coast line of the Gulf of Paria. Simple and low-cost methods of analysis were optimized and validated using standard reference materials. Cadmium, copper, lead, nickel, and zinc were analyzed by flame atomic absorption spectrometry. Mercury was determined by cold-vapor atomic absorption spectrometry. The present study has confirmed that oysters have a much greater capacity for accumulation of copper and zinc than does green mussel. In addition, concentrations of copper and zinc in oysters (Crassostrea sp.) at many of the sites in the Gulf of Paria exceeded local and international standards, whereas green mussel P. viridis contained generally acceptable levels for human consumption. PMID:11994781
Review of the Berosus Leach of Venezuela (Coleoptera, Hydrophilidae, Berosini) with description of fourteen new species.
Oliva, Adriana; Short, Andrew E Z
The species of the water scavenger beetle genus Berosus Leach occurring in Venezuela are reviewed. Thirty-six species are recorded, including fifteen new species, fourteen of which are described here as new: Berosus araguasp. n., Berosus asymmetricussp. n., Berosus capanaparosp. n., Berosus castaneussp. n., Berosus corozosp. n., Berosus ebeninussp. n., Berosus garciaisp. n., Berosus humeralissp. n., Berosus jolyisp. n., Berosus llanensissp. n., Berosus megaphallussp. n., Berosus ornaticollissp. n., Berosus repertussp. n., and Berosus tramidrumsp. n. The fifteenth new species, known from a single female, is left undescribed pending the collection of males. Twelve species are recorded from Venezuela for the first time: Berosus ambogynus Mouchamps, Berosus consobrinus Knisch, Berosus elegans Knisch, Berosus geayi d'Orchymont, Berosus ghanicus d'Orchymont, Berosus guyanensis Queney, Berosus holdhausi Knisch, Berosus marquardti Knisch, Berosus olivae Queney, Berosus reticulatus Knisch, Berosus wintersteineri Knisch, and Berosus zimmermanni Knisch. PMID:22811607
Population differentiation of the Chagas disease vector Triatoma maculata (Erichson, 1848) from Colombia and Venezuela.
Monsalve, Yoman; Panzera, Francisco; Herrera, Leidi; Triana-Chávez, Omar; Gómez-Palacio, Andrés
The emerging vector of Chagas disease, Triatoma maculata (Hemiptera, Reduviidae), is one of the most widely distributed Triatoma species in northern South America. Despite its increasing relevance as a vector, no consistent picture of the magnitude of genetic and phenetic diversity has yet been developed. Here, several populations of T. maculata from eleven Colombia and Venezuela localities were analyzed based on the morphometry of wings and the mitochondrial NADH dehydrogenase subunit 4 (ND4) gene sequences. Our results showed clear morphometric and genetic differences among Colombian and Venezuelan populations, indicating high intraspecific diversity. Inter-population divergence is suggested related to East Cordillera in Colombia. Analyses of other populations from Colombia, Venezuela, and Brazil from distinct eco-geographic regions are still needed to understand its systematics and phylogeography as well as its actual role as a vector of Chagas disease. PMID:27232127
Patellar maltracking is prevalent among patellofemoral pain subjects with patella alta: an upright, weightbearing MRI study
Pal, Saikat; Besier, Thor F.; Beaupre, Gary S.; Fredericson, Michael; Delp, Scott L.; Gold, Garry E.
The purpose of this study is to determine if patellar maltracking is more prevalent among patellofemoral (PF) pain subjects with patella alta compared to subjects with normal patella height. We imaged 37 PF pain and 15 pain free subjects in an open-configuration magnetic resonance imaging scanner while they stood in a weightbearing posture. We measured patella height using the Caton-Deschamps, Blackburne-Peel, Insall-Salvati, Modified Insall-Salvati, and Patellotrochlear indices, and classified the subjects into patella alta and normal patella height groups. We measured patella tilt and bisect offset from oblique-axial plane images, and classified the subjects into maltracking and normal tracking groups. Patellar maltracking was more prevalent among PF pain subjects with patella alta compared to PF pain subjects with normal patella height (two-tailed Fisher's exact test, p < 0.050). Using the Caton-Deschamps index, 67% (8/12) of PF pain subjects with patella alta were maltrackers, whereas only 16% (4/25) of PF pain subjects with normal patella height were maltrackers. Patellofemoral pain subjects classified as maltrackers displayed a greater patella height compared to the pain free and PF pain subjects classified as normal trackers (two-tailed unpaired t-tests with Bonferroni correction, p < 0.017). This study adds to our understanding of PF pain in two ways - 1) we demonstrate that patellar maltracking is more prevalent in PF pain subjects with patella alta compared to subjects with normal patella height; and 2) we show greater patella height in PF pain subjects compared to pain free subjects using four indices commonly used in clinics. PMID:23165335
Determination of genotypes of hepatitis C virus in Venezuela by restriction fragment length polymorphism.
Pujol, F H; Loureiro, C L; Devesa, M; Blitz, L; Parra, K; Beker, S; Liprandi, F
Hepatitis C virus genotypes in Venezuela were analyzed by restriction fragment length polymorphism in the 5' noncoding region. The absence of BstUI digestion was found to be a useful marker for genotype 2 specimens. From 122 serum samples, 66, 20, and 2.5% were classified as genotypes 1, 2, and 3, respectively; 0.8% were classified as genotype 4; and 10% appeared to be mixed infections. PMID:9196212
A new species of Piaroa (Schizomida: Hubbardiidae) from Venezuela, with taxonomic notes on the genus.
M, Osvaldo Villarreal; De Armas, Luis F; García, Luis Fernando
A new species belonging to the schizomid genus Piaroa Villarreal, Giupponi and Tourinho, 2008 is described from north-western Venezuela. A complementary description of Piaroa guipongai Villarreal and Garcia, 2012 is provided including SEM pictures of relevant structures of both sexes. A key for males of Piaroa and Colombiazomus Armas and Delgado-Santa, 2012 is included. The presence of Dm3 setae on Hubbardiidae is discussed. PMID:24870907
Applications of Planktonic foraminifera in the Paleogene of the Eastern Venezuela-Trinidad Basin
Radford, S.
Following increased interest in the petroleum potential of the Eastern Venezuela-Trinidad Basin, a revision of the planktonic foraminifera from the Paleogene was undertaken. The application of evolutionary trends in microperforate, medioperforate and macroperforate lineages for petroleum exploration is assessed. Scanning Electron Microscope illustrations are presented for over 100 taxa currently applied in high resolution biostratigraphy, sequence stratigraphy and paleoceanography of the region. These will allow more rapid and reliable recognition of zones, hiatuses and sequence boundaries.
Individuals in a Collectivist World: Born in the U.S.A., Teaching in Caracas, Venezuela
ERIC Educational Resources Information Center
Warring, Douglas F.; Huber-Warring, Tonya
Venezuela is a country slightly larger than twice the size of California, the third largest U.S.A. state in land area. Caracas, the capitol city, is home to a population of 6 million people nested into a space that is actually smaller in size than the area of Minneapolis-St. Paul, Minnesota, U.S.A., a city/suburb of only 2.8 million people. In…
Leptalpheus pereirai sp. nov., a new alpheid shrimp from Panama and Venezuela (Decapoda: Caridea).
Anker, Arthur; Caripe, Jonathan Vera
A new species of the infaunal alpheid shrimp genus Leptalpheus Williams, 1965 is described based on material from three localities on the Caribbean coast of Panama and Isla Chimana Grande, Venezuela. Leptalpheus pereirai sp. nov. belongs to a group of species characterised by the presence of well-developed adhesive disks on the major chela and appears to dwell in burrows of the large callianassid ghost shrimp, Glypturus acanthochirus Stimpson 1866. PMID:27395620
Evaluation of different methods of catching anopheline mosquitoes in western Venezuela.
Rubio-Palis, Y; Curtis, C F
During a longitudinal study of vector biology and malaria transmission in western Venezuela, adult mosquitoes were collected by different methods and their efficiency was compared with human landing catches. CDC light traps, a double-net, a calf-baited trap and collection of resting mosquitoes on vegetation were tested. These methods did not prove to be effective substitutes for human landing catches. PMID:1402863
Opportunities and constraints to biotechnological applications in the Caribbean: transgenic papayas in Jamaica and Venezuela.
Fermin, Gustavo; Tennant, Paula
In this opinion article, we briefly review the status of crop biotechnology research-with emphasis on the development of GM crops-in Jamaica and Venezuela. We focus on the transgenic papayas developed for both countries, and examine the factors hindering not only the development and application of this biotechnological commodity for the improvement of agricultural productivity, but also on the challenges influencing societal acceptance of the technology. PMID:21212960
Combined Rock Magnetic and Dielectric studies applied to stratigraphic and archeological problems in Venezuela
NASA Astrophysics Data System (ADS)
Costanzo-Alvarez, V.; Aldana, M.; Suarez, N.
In the last few years the paleomagnetism research group, at the Universidad Simon Bolivar in Caracas (Venezuela), has undertaken combined studies of rock magnetism (e.g. natural magnetic remanence, magnetic susceptibility, hysteresis parameters etc.) and dielectric properties (maximum current depolarization temperatures and average activation energies) in Cretaceous and Paleogene sedimentary sequences from eastern and western Venezuela. Our main goal has been to find new ways of defining physical markers, in fossil- poor sedimentary rocks, for stratigraphic correlations. Magneto/dielectric characterizations of these rocks have proved also useful identifying lithological discontinuities and paleoenvironmental changes. More recently these two-fold technique have been extended to archeological materials (potsherds) from a series of Venezuelan islands, in order to track down clay sources and find out about different stages of pottery craftsmanship. Magneto/Dielectric characterization of archeological potsherds seems to allow the tracing of their provenance from various mainland prehistoric settlements of distinct Venezuelan amerindian groups. In this paper we present a comprehensive review of this research applied to a contact between two sedimentary formations in eastern Venezuela (Cretaceous Chimana/Querecual) and a number of pottery samples with diverse stylistic features excavated in a single archeological site from Los Roques islands.
[Genetic and demographic structure of the State of Aragua, Venezuela, estimated through the surnames].
Rodríguez Larralde, A; Casique, J
The genetic structure of the State of Aragua, Venezuela, has been studied through the analysis of surnames obtained from the register of electors. The analysis covered 23 counties and included a total of 99,593 individuals and 6,338 different surnames. Estimators of isolation, consanguinity, microdifferentiation and four measures of genetic distance, were studied. When our results were compared with those obtained in other States of Venezuela studied previously (Falcón, Lara, Mérida, Nueva Esparta and Yaracuy), Aragua appears as the State most open to new migrants, probably due to its nearness to Caracas, Venezuela's capital city. Within Aragua, the counties most isolated are Choronií, Ocumare de la Costa and Tovar, while those less isolated are El Limón, Turmero, La Victoria, San Mateo and Cagua. The correlations between the logarithmic transformations of genetic and geographic distances were all significant, revealing surname differentiation by distance. The dendrogram built with the Euclidean distance matrix shows a first group of counties formed by those localized towards the central portion of the State, to which southern counties are added. Choroní and Ocumare de la Costa form a group which enters the dendrogram just before Tovar, the last county to be included in the analysis. Seven surnames with a focal distribution within the State were identified: Ayala and Calanche in Choroní; Kanzler, Misle and Ruh in Tovar; Lira in San Mateo and Santaella in Barbacoas. PMID:7483965
Venezuela near doubles proven reserves. 2. US protectionism and the geopolitics of petro-geology
Not Available
This issue honors the late Dan Lundberg, founder and former publisher of Energy Detente (ED). Mr. Lundberg founded ED a few months after his first visit to Venezuela in December 1979 and attending his first OPEC meeting. His acute awareness of factors affecting crises in oil markets was combined permanently in the publication founded in 1980, and it was designed from the very first to illuminate Western hemisphere and especially still-undeveloped hydrocarbon resources. Two unrelated events are treated as very much related in this issue: (A) The USA National Petroleum Council released Factors Affecting US Oil and Gas Outlook. (B) Almost simultaneously Petroleos de Venezuela, the national oil company of Venezuela released its new proven oil figures, close to 90% higher, at 55.5 billion barrels. The possible importance to US foreign policy is discussed. This issue of ED also contains: (1) ED refining netback data for the US Gulf and West Coasts, Rotterdam, and Singapore for mid March 1987; and (2) the ED fuel price/tax series March 1987 edition for countries of the Western Hemisphere. 8 figures, 6 tables.
[Direct genetic manipulation and criminal code in Venezuela: absolute criminal law void?].
Cermeño Zambrano, Fernando G De J
The judicial regulation of genetic biotechnology applied to the human genome is of big relevance currently in Venezuela due to the drafting of an innovative bioethical law in the country's parliament. This article will highlight the constitutional normative of Venezuela's 1999 Constitution regarding this subject, as it establishes the framework from which this matter will be legally regulated. The approach this article makes towards the genetic biotechnology applied to the human genome is made taking into account the Venezuelan penal law and by highlighting the violent genetic manipulations that have criminal relevance. The genetic biotechnology applied to the human genome has another important relevance as a consequence of the reformulation of the Venezuelan Penal Code discussed by the country's National Assembly. Therefore, a concise study of the country's penal code will be made in this article to better understand what judicial-penal properties have been protected by the Venezuelan penal legislation. This last step will enable us to identify the penal tools Venezuela counts on to face direct genetic manipulations. We will equally indicate the existing punitive loophole and that should be covered by the penal legislator. In conclusion, this essay concerns criminal policy, referred to the direct genetic manipulations on the human genome that haven't been typified in Venezuelan law, thus discovering a genetic biotechnology paradise. PMID:12379984
[Selenium content in the blood cattle from Venezuela. I. Central and Portugueste zones].
Otaiza, E R; Valeri, H; Cumare, V
Whole blood concentrations of selenium were determined in 776 dairy cows and calves from 28 farms located in three States (Aragua, Carabobo and Guárico) of the central zone of Venezuela and in Portuguesa State. Selenium levels largely varied according to both the geographic distribution and animals breed. Cattle from Guárico State showed the lowest average concentration (0.21 ppm) and those from Portuguesa the highest one (0.67 ppm). A group of animals from Turén (a District of Portuguesa State) showed the highest average concentration (1.64 ppm, range 1.02 +/- to 3.24 ppm). Concentrations of this magnitude in animals under grazing conditions could be related to high levels of selenium either in the soil or in the pasture. It is concluded that such animals are localized inaseleniferous zone (Turén). It must be noted that Jaffé et al. (op. cit.) found high levels of selenium in sesame seeds (Sesamum indicum) from this area and in blood and urine samples of children from Villa Bruzual, a little town of Turén. The results of this wok significantly differ from those obtained in other countries (of Europe and North America), where animals are managed under conditions very different from those of the tropical areas like Venezuela. The role this factor is discussed. This is the first report on blood levels in large animals of economical importance in Venezuela. PMID:931500
Distribution, status, and traditional significance of the West Indian manatee Trichechus manatus in Venezuela
O'Shea, Thomas J.; Correa-Viana, Martín; Ludlow, Mark E.; Robinson, John G.
Aerial and interview surveys were conducted in 1986 to determine the current distribution, status, and traditional significance of the West Indian manatee Trichechus manatus in Venezuela. Aerial surveys provided just eight tentative sightings in 73 hours of searching. These discouraging results may have been due to poor visibility, small populations, and perhaps reduced dry season manatee activity. Results of interview surveys, however, permitted a number of important generalizations. A remnant manatee population exists in Lake Maracaibo, but none occur along the more than 1500 km of Caribbean coastline. Abundance is greatest in eastern Venezuela bordering the Golfo de Paria, in the Orinoco Delta, and in the middle Orinoco and tributaries. Local market hunting in the middle of this century probably greatly reduced manatee populations in these areas. Recent protection laws, education efforts, and manatee scarcity have resulted in a declining interest in manatee hunting. Much excellent manatee habitat persists in these regions, and a continued decline in hunting could result in an optimistic outlook for future manatee populations if the incidental take in net fisheries is controlled. Traditional beliefs and legends concerning manatees in Venezuela, including hunting taboos, show that these animals remain a colorful part of the folk culture. However, manatee protection does not pose economic hardships or infringe upon traditional spiritual beliefs.
Receiver Functions Imaging of the Moho and LAB in the Southern Caribbean plate boundary and Venezuela
NASA Astrophysics Data System (ADS)
Masy, J.; Levander, A.; Niu, F.
We have made teleseismic Ps and Sp receiver functions from data recorded from 2003 to 2009 by the permanent national seismic network of Venezuela, the BOLIVAR (Broadband Onshore-offshore Lithospheric Investigation of Venezuela and the Antilles arc Region) and WAVE (Western Array for Venezuela) experiments. The receiver functions show rapid variations in Moho and lithosphere-asthenosphere boundary (LAB) depths both across and along the southern Caribbean plate boundary region. We used a total of 69 events with Mw > 6 occurring at epicentral distances from 30° to 90° for the Ps receiver functions, and 43 events with Mw > 5.7 from 55° to 85° to make Sp receiver functions. For CCP stacking we constructed a 3D velocity model from numerous active source profiles (Schmitz et al., 2001; Bezada et al., 2007; Clark et al., 2008; Guedez, 2008; Magnani et al., 2009), from finite-frequency P wave upper mantle tomography model of Bezada et al., (2010) and the Rayleigh wave tomography model of Miller et al., (2009). The Moho ranges in depth from ~25 km beneath the Caribbean Large Igneous Provinces to ~55 km beneath the Mérida Andes in western Venezuela. These results are consistent with previous receiver functions studies (Niu et al., 2007) and the available active source profiles. Beneath the Maracaibo Block in northwestern Venezuela, we observe a strong positive signal at 40 to 60 km depth dipping ~6° towards the continent. We interpret this as the Moho of the Caribbean slab subducting beneath northernmost South America from the west. Beneath northern Colombia and northwestern Venezuela the top of this slab has been previously inferred from intermediate depth seismicity (Malavé and Suarez, 1995), which indicates a slab dipping between 20° - 30° beneath Lake Maracaibo. Our results could indicate that the slab is tearing beneath Lake Maracaibo as suggested previously by Masy et al. (2011). The deeper (> 100 km depth) part of the slab has been imaged using P
Characterization and engineering of the ethylmalonyl-CoA pathway towards the improved heterologous production of polyketides in Streptomyces venezuelae.
Jung, Won Seok; Kim, Eunji; Yoo, Young Ji; Ban, Yeon Hee; Kim, Eun Ji; Yoon, Yeo Joon
Streptomyces venezuelae has an inherent advantage as a heterologous host for polyketide production due to its fast rate of growth that cannot be endowed easily through metabolic engineering. However, the utility of S. venezuelae as a host has been limited thus far due to its inadequate intracellular reserves of the (2S)-ethylmalonyl-CoA building block needed to support the biosynthesis of polyketides preventing the efficient production of the desired metabolite, such as tylactone. Here, via precursor supply engineering, we demonstrated that S. venezuelae can be developed into a more efficient general heterologous host for the quick production of polyketides. We first identified and functionally characterized the ethylmalonyl-CoA pathway which plays a major role in supplying the (2S)-ethylmalonyl-CoA extender unit in S. venezuelae. Next, S. venezuelae was successfully engineered to increase the intracellular ethylmalonyl-CoA concentration by the deletion of the meaA gene encoding coenzyme B₁₂-dependent ethylmalonyl-CoA mutase in combination with ethylmalonate supplementation and was engineered to upregulate the expression of the heterologous tylosin PKS by overexpression of the pathway specific regulatory gene pikD. Thus, a dramatic increase (∼10-fold) in tylactone production was achieved. In addition, the detailed insights into the role of the ethylmalonyl-CoA pathway, which is present in most streptomycetes, provides a general strategy to increase the ethylmalonyl-CoA supply for polyketide biosynthesis in the most prolific family of polyketide-producing bacteria. PMID:24413979
[A case of laparoscopic surgery for a rectal carcinoid after ALTA therapy for an internal hemorrhoid].
Aomatsu, Naoki; Nakamura, Masanori; Hasegawa, Tsuyoshi; Nakao, Shigetomi; Uchima, Yasutake; Aomatsu, Keiho
We report a case of laparoscopic surgery for a rectal carcinoid after aluminum potassium and tannic acid (ALTA) therapy for an internal hemorrhoid. A 66-year-old man was admitted to our hospital because of bleeding during defecation. He was diagnosed via anoscopy with Goligher grade II internal hemorrhoids. Examination via colonoscopy revealed 2 yellowish submucosal tumors in the lower rectum that were 5mm and 10mm in diameter. A rectal carcinoid tumor was diagnosed based on histopathology. Abdominal computed tomography demonstrated no metastases to the liver or lymph nodes. First, we performed ALTA therapy for the internal hemorrhoids. Two weeks later, we performed laparoscopic-assisted low anterior resection (D2) for the rectal carcinoid. The patient was discharged without complications and has not experienced recurrence during the 2 years of follow-up care. PMID:25731340
Semitendinosus Tendon Transfer Associated With Distal Alignment for Patella Alta in a Patient With Recurrent Dislocations
Calderazzi, Filippo; Pellegrini, Andrea; Coviello, Gianluca; Groppi, Giulia; Ceccarelli, Francesco
Patellofemoral instability is characterized by pain during normal daily activities and frequent dislocation events. In the reported case, an adolescent girl, aged 15 years, affected by left patellofemoral instability, underwent surgery with a double technique comprising tibial tubercle distalization and medial patellofemoral ligament reconstruction. In case of patella alta associated with patellofemoral instability, surgical treatment should focus on medial patellofemoral ligament repair and on recurrent instability prevention. PMID:26900548
Cutaneous leishmaniasis due to Leishmania chagasi/Le. infantum in an endemic area of Guarico State, Venezuela.
De Lima, H; Rodríguez, N; Feliciangeli, M D; Barrios, M A; Sosa, A; Agrela, I; Sánchez, E; Lopez, O
This study reports cutaneous leishmaniasis (CL) caused by Leishmania chagasi/Le. infantum in Venezuela, with some atypical characteristics. Out of 63 cases of CL in the suburbs of Altagracia de Orituco, Guarico State, Venezuela, 30 presented clinical, parasitological, immunological and epidemiological features different from those of the classical CL known in the country. The initial lesion was small and nodular, which, if not treated, might progress to a superficial ulcer. No secondary infection was observed. The identification of the isolates was carried out by molecular techniques. Twelve species of phlebotomine sandflies were caught, the most abundant being Lutzomyia evansi and Lu. longipalpis s.l., known vectors of Le. chagasi/Le. infantum. The existence of Le. chagasi/Le. infantum and its vectors in an endemic area of CL has implications and we suggest that epidemiological studies should be carried out to obtain a clearer picture of the extent of this CL form in Venezuela. PMID:19150102
Microseismicity evidence for subduction of the Caribbean plate beneath the South American Plate in northwestern Venezuela
NASA Astrophysics Data System (ADS)
PéRez, Omar J.; Jaimes, Martha A.; Garciacaro, Emilio
Over 1100 microearthquakes with body wave magnitude mb<4 have been located in western Venezuela and the southwestern Caribbean region since the installation in 1980 of the Venezuelan Seismological Array, together with 120 events of mb≥4, one of them with surface wave magnitude Ms˜6. This tectonically complex region is part of the boundary between the Caribbean and the South American plates. The main seismically active feature inland in western Venezuela is the northeast striking, 600-km long, 100-km wide, right-lateral strike-slip Boconó fault zone along the Venezuelan Andes. About 80% of the earthquakes located in the entire region in the period 1980-mid-1995 have occurred on this fault zone, at focal depths <20 km. Microearthquake activity at lower rates also occurs northwest of the Venezuelan Andes, both in the continental and Caribbean sea regions. Part of this activity takes place at depths down to ˜150 km. Northwest oriented seismicity depth profiles show the existence of a Benioff zone dipping to the southeast beneath northwestern Venezuela and northern Colombia. This indicates the presence of a northeast striking, southeast dipping subducted slab of the Caribbean plate beneath the South American plate. Hypocentral locations show that the northeastern end of this subduction occurs northwest of the Curaçao-Aruba region, in the vicinity of a northwest trending, right-lateral strike-slip fault zone that joins up with the northeastern end of the Boconó fault zone. This latter place turns out to be the western end of the east-west striking San Sebastián fault along the Venezuelan coast.
Residential energy use and conservation in Venezuela: Results and implications of a household survey in Caracas
Figueroa, M.J.; Ketoff, A.; Masera, O.
This document presents the final report of a study of residential energy use in Caracas, the capital of Venezuela. It contains the findings of a household energy-use survey held in Caracas in 1988 and examines options for introducing energy conservation measures in the Venezuelan residential sector. Oil exports form the backbone of the Venezuelan economy. Improving energy efficiency in Venezuela will help free domestic oil resources that can be sold to the rest of the world. Energy conservation will also contribute to a faster recovery of the economy by reducing the need for major investments in new energy facilities, allowing the Venezuelan government to direct its financial investments towards other areas of development. Local environmental benefits will constitute an important additional by-product of implementing energy-efficiency policies in Venezuela. Caracas`s residential sector shows great potential for energy conservation. The sector is characterized by high saturation levels of major appliances, inefficiency of appliances available in the market, and by careless patterns of energy use. Household energy use per capita average 6.5 GJ/per year which is higher than most cities in developing countries; most of this energy is used for cooking. Electricity accounts for 41% of all energy use, while LPG and natural gas constitute the remainder. Specific options for inducing energy conservation and energy efficiency in Caracas`s residential sector include energy-pricing policies, fuel switching, particularly from electricity to gas, improving the energy performance of new appliances and customer information. To ensure the accomplishment of an energy-efficiency strategy, a concerted effort by energy users, manufacturers, utility companies, government agencies, and research institutions will be needed.
Pneumococcal carriage among indigenous Warao children in Venezuela: serotypes, susceptibility patterns, and molecular epidemiology.
Rivera-Olivero, Ismar A; Bogaert, Debby; Bello, Teresita; del Nogal, Berenice; Sluijter, Marcel; Hermans, Peter W M; de Waard, Jacobus H
Little attention has been paid to pneumococcal carriage and disease in Amerindians from Latin America. The Warao people, an indigenous population from Venezuela, live in the delta of the Orinoco River in geographically isolated communities with difficult access to medical care. To obtain insight into pneumococcal carriage and the theoretical coverage of pneumococcal vaccines in this population, we investigated pneumococcal colonization, serotype, and genotype distribution among Warao children in 9 distinct, geographically isolated communities in the Delta Amacuro area in the northeast of Venezuela. From April 2004 through January 2005, a total of 161 Streptococcus pneumoniae isolates were recovered from single nasopharyngeal swab samples obtained from 356 children aged 0-72 months. The overall pneumococcal carriage rate was 49%, ranging from 13% to 76%, depending on the community investigated and the age of the children (50% among children aged <2 years and 25% among children aged >2 years). The most frequent serotypes were 23F (19.5% of isolates), 6A (19.5%), 15B (10.4%), 6B (9.1%), and 19F (7.2%). The theoretical coverage of the 7-valent pneumococcal conjugate vaccine, including the cross-reactive nonvaccine serotype 6A, was 65%. A total of 26% of the isolates were resistant to first-line antibiotics, with 70% of these strains being covered by the 7-valent pneumococcal conjugate vaccine. Restriction fragment end labelling analysis revealed 65 different genotypes, with 125 (80%) of the isolates belonging to 27 different genetic clusters, suggesting a high degree of horizontal spread of pneumococcal strains in and between the villages. The high colonization rates and high (registered) acute respiratory tract infection morbidity and mortality in this part of Venezuela suggest that Warao children are at increased risk for pneumococcal disease and, therefore, benefit from vaccination. PMID:17990224
[Urban construction, professions, and immigration at the origin of urban studies in Venezuela, 1870-1957].
Martin Frechilla, J J
The individuals and circumstances involved in the creation of the first graduate urban studies program in Venezuela are recalled, beginning with the odernization of Caracas under the impulse of President Antonio Guzman Blanco, elected in 1870. Guzman Blanco converted himself into Venezuela's first urbanist with the establishment of organizational frameworks and completion of massive public works projects, which were based largely on the urban models of the US and Europe. Engineering and public health were consolidated as the two most influential sources of professional competence for guiding urban development. By the mid-1930s, growth fueled by petroleum revenues was causing rapid urbanization, and it became apparent that trained professionals able to manage the increasingly complex tasks of urban planning were in short supply. A new surge of modernizing construction began in 1936 and led to a cooperative arrangement with a French firm, whose personnel were to be required to train Venezuelan engineers for future service in urban planning. An influx of refugees from the Spanish Civil War and the increasing influence of urban planning processes in the US were also observed. The National Commission on Urbanism was created in 1946 as a dependency of the Ministry of Planning to facilitate public administration of the development and control of cities. Throughout the period, a debate was underway on the need for a multidisciplinary approach to urban planning versus a primarily architectural or engineering approach. In 1957, some consensus was reached on the need for urban planning to be viewed as more than a speciality of architecture. A framework was developed for a graduate program in 1969 in the Central University of Venezuela. The National Commission on Urbanism was disbanded in 1957, largely because of its excessive focus on architecture to the exclusion of other disciplines relevant to the urbanization process. PMID:12321404
Microfilaria bolivarensis: a new species of filaria from man in Venezuela.
Godoy, G A; Orihel, T C; Volcan, G S
An unsheathed microfilaria, unlike any other already described from man, was found in thick blood smears and Knott samples taken from Amerinds living along the upper Caura River in Bolivar State, Venezuela. The mirofilaria, which measures 256 x 7-8 micrometers in thick blood smears and 300 x 8 micrometers in Knott samples, is easily differentiated morphologically from Mansonella ozzardi with which it often occurs concomitantly. It is readily differentiated, on morphological criteria, from all other species of filariae which infect man, as well. The parasite has been named Microfilaria bolivarensis after the geographical locality in which it was discovered. PMID:7406105
Molecular Evidence of Anaplasma platys Infection in Two Women from Venezuela
Arraga-Alvarado, Cruz M.; Qurollo, Barbara A.; Parra, Omaira C.; Berrueta, Maribel A.; Hegarty, Barbara C.; Breitschwerdt, Edward B.
This article presents two case reports of Anaplasma platys detection in two women from Venezuela. Both patients were exposed to Rhipicephalus sanguineus, the presumed tick vector, and experienced chronic, nonspecific clinical signs including headaches and muscle pains. Intra-platelet inclusion bodies resembling A. platys were observed in buffy coat smears and A. platys DNA was amplified and sequenced from whole blood; however, treatment with doxycycline did not alleviate their symptoms. These cases provide further support for A. platys as a zoonotic tick-borne pathogen, most likely of low pathogenicity; nonetheless, the cause of illness in humans by A. platys is yet to be confirmed. PMID:25266347
A novel Streptomyces spp. integration vector derived from the S. venezuelae phage, SV1
Background Integrating vectors based on the int/attP loci of temperate phages are convenient and used widely, particularly for cloning genes in Streptomyces spp. Results We have constructed and tested a novel integrating vector based on g27, encoding integrase, and attP site from the phage, SV1. This plasmid, pBF3 integrates efficiently in S. coelicolor and S. lividans but surprisingly fails to generate stable integrants in S. venezuelae, the natural host for phage SV1. Conclusion pBF3 promises to be a useful addition to the range of integrating vectors currently available for Streptomyces molecular genetics. PMID:24885867
Sentinel Surveillance of Influenza-Like Illness in Two Hospitals in Maracay, Venezuela: 2006–2010
Comach, Guillermo; Teneza-Mora, Nimfa; Kochel, Tadeusz J.; Espino, Carlos; Sierra, Gloria; Camacho, Daria E.; Laguna-Torres, V. Alberto; Garcia, Josefina; Chauca, Gloria; Gamero, Maria E.; Sovero, Merly; Bordones, Slave; Villalobos, Iris; Melchor, Angel; Halsey, Eric S.
Background Limited information exists on the epidemiology of acute febrile respiratory illnesses in tropical South American countries such as Venezuela. The objective of the present study was to examine the epidemiology of influenza-like illness (ILI) in two hospitals in Maracay, Venezuela. Methodology/Principal Findings We performed a prospective surveillance study of persons with ILI who presented for care at two hospitals in Maracay, Venezuela, from October 2006 to December 2010. A respiratory specimen and clinical information were obtained from each participant. Viral isolation and identification with immunofluorescent antibodies and molecular methods were employed to detect respiratory viruses such as adenovirus, influenza A and B, parainfluenza, and respiratory sincytial virus, among others. There were 916 participants in the study (median age: 17 years; range: 1 month – 86 years). Viruses were identified in 143 (15.6%) subjects, and one participant was found to have a co-infection with more than one virus. Influenza viruses, including pandemic H1N1 2009, were the most frequently detected pathogens, accounting for 67.4% (97/144) of the viruses detected. Adenovirus (15/144), parainfluenza virus (13/144), and respiratory syncytial virus (11/144) were also important causes of ILI in this study. Pandemic H1N1 2009 virus became the most commonly isolated influenza virus during its initial appearance in 2009. Two waves of the pandemic were observed: the first which peaked in August 2009 and the second - higher than the preceding - that peaked in October 2009. In 2010, influenza A/H3N2 re-emerged as the most predominant respiratory virus detected. Conclusions/Significance Influenza viruses were the most commonly detected viral organisms among patients with acute febrile respiratory illnesses presenting at two hospitals in Maracay, Venezuela. Pandemic H1N1 2009 influenza virus did not completely replace other circulating influenza viruses during its initial
Diurnal raptors in the fragmented rain forest of the Sierra Imataca, Venezuela
Alvarez, E.; Ellis, D.H.; Smith, D.G.; LaRue, C.T.
The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 42 species of diurnal raptors observed in affected areas in this region. We observed some raptors considered as forest interior species and other open country species foraging and roosting in man-made openings inside the forest.
Diurnal raptors in the fragmented rain forest of the Sierra Imataca, Venezuela
Alvarez, E.; Ellis, D.H.; Smith, D.G.; LaRue, C.T.
The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 40 species of diurnal raptors observed in ten affected areas, including raptors considered as forest interior species and some open country species utilizing the man-made openings inside the forest for roosting and foraging.
Influence of moonlight on light trap catches of the malaria vector Anopheles nuneztovari in Venezuela.
Rubio-Palis, Y
A significant effect (P = 0.002) of moonlight on light trap catches of Anopheles nuneztovari females was observed during a longitudinal study in western Venezuela. The catch with no moon was 1.86 times larger than with full moon. Nevertheless, moonlight does not seem to have any effect on the composition of adult mosquito population since the difference in the parous rate of females collected during full moon and during no moon was not significant (P greater than 0.05). PMID:1431859
Host choice of anopheline mosquitoes in a malaria endemic area of western Venezuela.
Rubio-Palis, Y; Curtis, C F; Gonzáles, C; Wirtz, R A
Bloodmeals of exophilic anopheline mosquitoes collected resting on vegetation in a malaria endemic area in western Venezuela were identified by ELISA. Using a TMB peroxidase substrate in the ELISA, human bloodmeals were readily identified up to 40 h after ingestion in all laboratory-fed mosquitoes tested. Assay sensitivity declined to 75% identifiable 44 h post-feeding. The Human Blood Index and the Feeding Index of each species differed between the three villages studied. An.triannulatus was generally more anthropophilic than An.nuneztovari and An.oswaldoi. These contrasting results emphasize the difficulties of interpreting host choice data. PMID:7949319
A study on the genus Agrilaxia Kerremans, 1903 from Venezuela (Coleoptera: Buprestidae: Buprestinae: Anthaxiini).
Bílý, Svatopluk
Study on the genus Agrilaxia Kerremans, 1903 from Venezuela. Altogether eight species were recorded from this country, four of them are described in this paper: Agrilaxia (Agrilaxia) biformis sp. nov., A. (A.) michaeli sp. nov., A. (A.) stephani sp. nov. and A. (A.) venezuelana sp. nov. All species are illustrated and new species are compared with the most similar/related species. A male of Agrilaxia (A.) balloui Fisher, 1942 is described and the male genitalia are illustrated. New country records are given for Agrilaxia (A.) balloui, A. (A.) costaricensis Obenberger, 1922, A. (A.) glabra Bílý & Brûlé 2013 and A. (A.) simillima Cobos, 1972. PMID:26624473
Evaluacion de Programas de Alfabetizacion. Consulta Tecnica Regional (Maracaibo, Venezuela, 30 Noviembre-6 Diciembre 1987) Informe Final. (Evaluation of Literacy Programs. Regional Technical Meeting (Maracaibo, Venezuela, November 30-December 6, 1987).
ERIC Educational Resources Information Center
United Nations Educational, Scientific, and Cultural Organization, Santiago (Chile). Regional Office for Education in Latin America and the Caribbean.
The objectives of this seminar were to identify problems in evaluating literacy programs and to design a working strategy to confront them. Four presentations included national case studies from Brazil, Honduras, Nicaragua, and Venezuela. Central questions asked concerned who and what were evaluated and how were the results to be used. In Brazil,…
[Seasonality of rotavirus infection in Venezuela: relationship between monthly rotavirus incidence and rainfall rates].
González Chávez, Rosabel
In general, it has been reported that rotavirus infection was detected year round in tropical countries. However, studies in Venezuela and Brazil suggest a seasonal behavior of the infection. On the other hand, some studies link infection with climatic variables such as rainfall. This study analyzes the pattern of behavior of the rotavirus infection in Carabobo-Venezuela (2001-2005), associates the seasonality of the infection with rainfall, and according to the seasonal pattern, estimates the age of greatest risk for infection. The analysis of the rotavirus temporal series and accumulated precipitation was performed with the software SPSS. The infection showed two periods: high incidence (November-April) and low incidence (May-October). Accumulated precipitation presents an opposite behavior. The highest frequency of events (73.8% 573/779) for those born in the period with a low incidence of the virus was recorded at an earlier age (mean age 6.5 +/- 2.0 months) when compared with those born in the station of high incidence (63.5% 568/870, mean age 11.7 +/- 2.2 months). Seasonality of the infection and the inverse relationship between virus incidence and rainfall was demonstrated. In addition, it was found that the period of birth determines the age and risk of infection. This information generated during the preaccine period will be helpful to measure the impact of the vaccine against the rotavirus. PMID:26710540
Spinocerebellar ataxias in Venezuela: genetic epidemiology and their most likely ethnic descent.
Paradisi, Irene; Ikonomu, Vassiliki; Arias, Sergio
Dominantly inherited ataxias (spinocerebellar ataxias, SCAs) are a genetically heterogeneous group of neurologic diseases characterized by progressive cerebellar and spinal tract degeneration with ataxia and other signs, common to all known subtypes. Several types are relatively frequent worldwide, but in several countries, one specific SCA may show a higher prevalence owing to founder phenomena. In Venezuela, genetic epidemiological features of SCAs have been assessed during the last 30 years; mutations in ATXN1 (SCA1), ATXN2 (SCA2), ATXN3 (SCA3), CACNA1A (SCA6), ATXN7 (SCA7), ATXN8 (SCA8), ATXN10 (SCA10), TBP (SCA17) and ATN1 (dentatorubral pallidoluysian atrophy, DRPLA) loci were searched among 115 independent families. SCA7 was the most frequent subtype (26.6%), followed by SCA3 (25.0%), SCA2 (21.9%), SCA1 (17.2%), SCA10 (4.7%) and DRPLA (3.1%); in 43% of the families, the subtype remained unidentified. SCA7 mutations displayed strong geographic aggregation in two independent founder foci, and SCA1 showed a very remote founder effect for a subset of families. SCA10 families were scattered across the country, but all had an identical in-phase haplotype carried also by Mexican, Brazilian and Sioux patients, supporting a very old common Amerindian origin. Prevalence for dominant SCAs in Venezuela was estimated as 1:25 000 nuclear families, provenances of which are either Caucasoid, African or Amerindian. PMID:26538302
Paleogeographic evolution of foldbelts adjacent to petroleum basins of Venezuela and Trinidad
Goodman, E.D.; Koch, P.S.; Summa, L.L.
The foldbelts of Venezuela and Trinidad have shaped the history of adjacent sedimentary basins. A set of paleogeographic maps on reconstructed bases depict the role of foldbelts in the development of the sedimentary basins of Venezuela. Some of the foldbelts are inverted, pre-Tertiary graben/passive margin systems. Other foldbelts are allochthonous nappes or parautochthons that override the Mesozoic passive margin hinge without inversion. The emergence of these foldbelts changed the course of existing river systems and provided a new source for sediments and maturation in adjacent deeps. The Merida Andes area was remobilized beginning in the Early Miocene as a zone of lateral shear, along which the Bonaire Block has moved over 200 km to the northeast, dismembering the Maracaibo and Barinas basins. Late Miocene to Recent transpression and fault reactivation have driven rapid Andean uplift with thrust-related subsidence and maturation (e.g., SE Maracaibo foredeep). To the east, uplift and erosion of the Serrania del Interior (1) curtailed mid-Tertiary fluvial systems flowing northward from the igneous and sedimentary rocks of the Guyana Shield, deflecting them eastward, and (2) removed the thick early Miocene foredeep fill into a younger foredeep. Thus, the fold-thrust belts and sedimentary basins in this region are linked in their evolutionary histories.
Comparison of the petroleum systems of East Venezuela in their tectonostratigraphic context
Stronach, N.J.; Kerr, H.M.; Scotchmer, J.; Hunter, V.
The Maturin and Guarico subbasins of East Venezuela record the transition from Cretaceous passive margin to Tertiary foreland basin with local post-orogenic transtensional basins. Petroleum is reservoired in several units ranging from Albian (El Cantil Formation) to Pliocene (Las Piedras Formation) age. Source rocks are principally in the Upper Cretaceous (Querecual Formation), and Miocene (Carapita Formation) in the Maturin subbasin and in the Upper Cretaceous (Tigre Formation) and Oligocene (Roblecito and La Pascua Formations) in the Guarico subbasin. An extensive well database has been used to address the distribution and provenance of hydrocarbons in the context of a tectonostratigraphic model for the evolution of the East Venezuela basin. Nine major plays have been described, comprising thirteen petroleum systems. The principal factors influencing the components of individual petroleum systems are as follows: (1) structural controls on Upper Cretaceous source rock distribution, relating to block faulting on the proto-Caribbean passive margin; (2) paleoenvironmental controls on source rock development within the Oligocene-Miocene foreland basin; and (3) timing of subsidence and maturation within the Oligocene-Upper Miocene foreland basin and the configuration of the associated fold and thrust belt, influencing long range and local migration routes (4) local development of Pliocene post-orogenic transtensional basins, influencing hydrocarbon generation, migration and remigration north of the Pirital High.
[Mollusc diversity in an Arca zebra (Mollusca: Bivalvia) community, Chacopata, Sucre, Venezuela].
Prieto, A S; Ruiz, L J; García, N; Alvarez, M
The diversity of a subtidal epifaunal mollusk community was studied from September, 1990 to September, 1991 in Chacopata, Sucre State, Venezuela. There were 40 species (24 bivalves and 16 gastropods). The diversity indexes (H' = 2.087, J' = 0.392, 1/D = 0.528) were low when compared with other tropical zones. Monthly diversity reached its maximum in September, 1990 (1.63 bits/ind.) and July, 1991 (1.60 bits/ind.); minimum diversity occurred in June, 1991 (0.52 bits/ind.). A Log series model applied to species abundance data showed a straight line with a diversity index alpha of 5.56. Of 40 species identified, the turkeywing Arca zebra was dominant (69% in number of individuals and 72% of biomass) followed by Pinctada imbricata, Modiolus squamosus, Chama macerophyla and Anadara notabilis. The predatory snails Phyllonotus pomum, Chicoreus brevifrons and Murex recurvirostris seemed to have trophic relationships with A. zebra. The total mean biomass in wet weight (469.20 +/- 263 g m-2, shell included) was high which indicates that A. zebra, a species with a rapid growth rate, occupies a central role in the assemblage as an efficient filter feeder that converts planktonic food into available biomass, supporting one of the most important fisheries in Venezuela. PMID:11935909
Evolutionary and Ecological Characterization of Mayaro Virus Strains Isolated during an Outbreak, Venezuela, 2010
Auguste, Albert J.; Liria, Jonathan; Forrester, Naomi L.; Giambalvo, Dileyvic; Moncada, Maria; Long, Kanya C.; Morón, Dulce; de Manzione, Nuris; Tesh, Robert B.; Halsey, Eric S.; Kochel, Tadeusz J.; Hernandez, Rosa; Navarro, Juan-Carlos
In 2010, an outbreak of febrile illness with arthralgic manifestations was detected at La Estación village, Portuguesa State, Venezuela. The etiologic agent was determined to be Mayaro virus (MAYV), a reemerging South American alphavirus. A total of 77 cases was reported and 19 were confirmed as seropositive. MAYV was isolated from acute-phase serum samples from 6 symptomatic patients. We sequenced 27 complete genomes representing the full spectrum of MAYV genetic diversity, which facilitated detection of a new genotype, designated N. Phylogenetic analysis of genomic sequences indicated that etiologic strains from Venezuela belong to genotype D. Results indicate that MAYV is highly conserved genetically, showing ≈17% nucleotide divergence across all 3 genotypes and 4% among genotype D strains in the most variable genes. Coalescent analyses suggested genotypes D and L diverged ≈150 years ago and genotype diverged N ≈250 years ago. This virus commonly infects persons residing near enzootic transmission foci because of anthropogenic incursions. PMID:26401714
Prevalence of antibodies against hepatitis E virus among urban and rural populations in Venezuela.
Pujol, F H; Favorov, M O; Marcano, T; Esté, J A; Magris, M; Liprandi, F; Khudyakov, Y E; Khudyakova, N S; Fields, H A
Antibodies against hepatitis E virus (HEV) were detected in sera by a synthetic peptide-based enzyme immunoassay (EIA) from different populations in Venezuela. Antibodies against HEV were found in 1.6% (3/184) of urban pregnant woman (Caracas), in 3.9% (8/204) of rural populations (San Camilo, Edo Apure), and in 5.4% (12/223) of rural Amerindians (Padamo, Edo Amazonas). Positivity was confirmed by a neutralization EIA based on the use of competing soluble free peptides. The prevalence of antibodies in the Amerindian group was significantly higher than in urban pregnant women. No relation was found between age and HEV prevalence in rural populations. Three of 21 positive sera were also weakly positive by Western blot for IgM antibodies. This result, together with the low optical density values observed by EIA, suggested that the presence of antibodies in these sera reflects past infections. Based on these results, Venezuela does not seem to be highly endemic for hepatitis E. This is the first report of serological evidence of infection by HEV in South America. PMID:8006635
An Estimate of Recoverable Heavy Oil Resources of the Orinoco Oil Belt, Venezuela
Schenk, Christopher J.; Cook, Troy A.; Charpentier, Ronald R.; Pollastro, Richard M.; Klett, Timothy R.; Tennyson, Marilyn E.; Kirschbaum, Mark A.; Brownfield, Michael E.; Pitman, Janet K.
The Orinoco Oil Belt Assessment Unit of the La Luna-Quercual Total Petroleum System encompasses approximately 50,000 km2 of the East Venezuela Basin Province that is underlain by more than 1 trillion barrels of heavy oil-in-place. As part of a program directed at estimating the technically recoverable oil and gas resources of priority petroleum basins worldwide, the U.S. Geological Survey estimated the recoverable oil resources of the Orinoco Oil Belt Assessment Unit. This estimate relied mainly on published geologic and engineering data for reservoirs (net oil-saturated sandstone thickness and extent), petrophysical properties (porosity, water saturation, and formation volume factors), recovery factors determined by pilot projects, and estimates of volumes of oil-in-place. The U.S. Geological Survey estimated a mean volume of 513 billion barrels of technically recoverable heavy oil in the Orinoco Oil Belt Assessment Unit of the East Venezuela Basin Province; the range is 380 to 652 billion barrels. The Orinoco Oil Belt Assessment Unit thus contains one of the largest recoverable oil accumulations in the world.
Assessing the Educational and Financial Needs of Small-Scale Dairy Farmers in Socopo, Venezuela. Summary of Research 64.
ERIC Educational Resources Information Center
Nieto, Ruben D.; Henderson, Janet L.
The process of transferring agricultural technology in many countries was studied to determine the perceived educational and financial needs of small-scale dairy farmers in Socopo, Venezuela. The following data were collected: (1) demographic characteristics--age, educational level, farm size, number of lactating cows, dairy farming experience,…
Are Returns to Education on the Decline in Venezuela and Does Mission Sucre Have a Role to Play?
ERIC Educational Resources Information Center
Gonzalez, Naihobe; Oyelere, Ruth Uwaifo
Anecdotal evidence points to a falling standard of living for the educated in Venezuela. During this same period, President Hugo Chavez implemented several education reforms. We focus on a major university education reform known as Mission Sucre and its potential impact on returns to university education. First, we show that returns to education…
Preliminary assessment of a Cretaceous-Paleogene Atlantic passive margin, Serrania del Interior and Central Ranges, Venezuela/Trinidad
Pindell, J.L.; Drake, C.L. ); Pitman, W.C. )
For several decades, Cretaceous arc collision was assumed along northern Venezuela based on isotopic ages of metamorphic minerals. From subsidence histories in Venezuelan/Trinidadian basins, however, it is now clear that the Cretaceous metamorphic rocks were emplaced southeastward as allochthons above an autochthonous suite of rocks in the Cenozoic, and that the pre-Cenozoic autochthonous rocks represent a Mesozoic passive margin. The passive margin rocks have been metamorphosed separately during overthrusting by the allochthons in central Venezuela, but they are uplifted but not significantly metamorphosed in Eastern Venezuela and Trinidad. There, in the Serrania del Interior and Central Ranges of Venezuela/Trinidad, Mesozoic-Paleogene passive margin sequences were uplifted in Neogene time, when the Caribbean Plate arrived from the west and transpressionally inverted the passive margin. Thus, this portion of South America's Atlantic margin subsided thermally without tectonism from Jurassic to Eocene time, and these sections comprise the only Mesozoic-Cenozoic truly passive Atlantic margin in the Western Hemisphere that is now exposed for direct study. Direct assessments of sedimentological, depositional and faunal features indicative of, and changes in, water depth for Cretaceous and Paleogene time may be made here relative to a thermally subsiding passive margin without the complications of tectonism. Work is underway, and preliminary assessments presented here suggest that sea level changes of Cretaceous-Paleogene time are not as pronounced as the frequent large and rapid sea level falls and rises that are promoted by some.
Situation Report--Burma, Chile, German Democratic Republic, Indonesia, Jamaica, Poland, Singapore, St. Christopher/Nevis, Trinidad & Tobago, Venezuela.
ERIC Educational Resources Information Center
International Planned Parenthood Federation, London (England).
Data relating to population and family planning in ten foreign countries are presented in these situation reports. Countries included are Burma, Chile, German Democratic Republic, Indonesia, Jamaica, Poland, Singapore, St. Christopher/Nevis, Trinidad and Tobago, and Venezuela. Information is provided, where appropriate and available, under two…
Complete genome sequence of Streptomyces venezuelae ATCC 15439, a promising cell factory for production of secondary metabolites.
Song, Ju Yeon; Yoo, Young Ji; Lim, Si-Kyu; Cha, Sun Ho; Kim, Ji-Eun; Roe, Jung-Hye; Kim, Jihyun F; Yoon, Yeo Joon
Streptomyces venezuelae ATCC 15439, which produces 12- and 14-membered ring macrolide antibiotics, is a platform strain for heterologous expression of secondary metabolites. Its 9.05-Mb genome sequence revealed an abundance of genes involved in the biosynthesis of secondary metabolites and their precursors, which should be useful for the production of bioactive compounds. PMID:26718561
The Alta Stock, Utah: An Exemplar Rock Suite for Learning Metamorphic Concepts
NASA Astrophysics Data System (ADS)
Davidson, C.; Haileab, B.
Using rock suites in a discovery-based setting is a terrific way to learn important petrologic processes and concepts such as the role of fluids during metamorphism, phase equilibrium, and metastability to name just a few. A particularly effective rock suite we use in our petrology course is from the contact aureole of the Tertiary Alta stock in Utah. The intrusion of the Alta stock into Paleozoic dolostone containing chert nodules produced a well-defined contact metamorphic aureole that includes talc-, tremolite-, forsterite-, and periclase-in field isograds (Cook and Bowman, 2000). Students work in free-form groups with collaboration between groups to define the mineral assemblages using hand samples and thin sections from throughout the areole and then work out what they think are the important petrologic processes that worked together to form what they see. The main goals of the exercise include: 1) learning to identify mineral assemblages common to metamorphosed siliceous dolostones; 2) learning to infer metamorphic reactions from progressive changes in mineral assemblages; 3) being able to identify balanced metamorphic reactions responsible for isograds mapped in the field; 4) begin to develop an understanding of how bulk composition and fluid composition controls mineral assemblages; and 5) learning how to infer the temperature and fluid composition evolution of the Alta stock aureole based on published T-X(CO2)diagrams. This suite is particularly effective because all the important minerals the students observe in thin section can be defined by the easy to plot and understand CaO-MgO-SiO2 system. This offers the opportunity to introduce (or reinforce) the concept of plotting minerals in composition space, using the phase rule to define the variance of your system, using tie lines to define stable mineral assemblages, and the flipping of tie lines to produce univariant reactions. In addition, the students work out the topology of these reactions in P-T space
Resultados del relevamiento de HI en el Cielo Austral: 3. Relevamiento de Nubes de Alta Velocidad
NASA Astrophysics Data System (ADS)
Morras, R.; Bajaja, E.; Arnal, E. M.; Pöppel, W. G. L.
Los resultados del relevamiento de HI del Hemisferio Austral fueron reprocesados con el fin de incrementar su sensibilidad. Así, se utilizó esta nueva base de datos con el fin de obtener un nuevo relevamiento de Nubes de Alta Velocidad en el cielo austral. El ruido r.m.s. alcanzado es de 0.015-0.020 K, con una resolución espectral de 8 km/seg. El cubrimiento espacial del relevamiento mejora en un factor 16 al realizado por Bajaja et al (1985).
Karyotype of the invasive species Pterois volitans (Scorpaeniformes: Scorpaenidae) from Margarita Island, Venezuela.
Nirchio, Mauro; Ehemann, Nicolás; Siccha-Ramirez, Raquel; Ron, Ernesto; Pérez, Julio Eduardo; Rossi, Anna Rita; Oliveira, Claudio
The genus Pterois includes nine valid species, native to the Red Sea and Indian Ocean throughout the Western Pacific. P. volitans and P. miles are native to the Indo-Pacific, and were introduced into Florida waters as a result of aquarium releases, and have been recently recognized as invaders of the Western Atlantic and Caribbean Sea (Costa Rica to Venezuela). Thus far, cytogenetic studies of the genus Pterois only cover basic aspects of three species, including P. volitans from Indo-Pacific Ocean. Considering the lack of more detailed information about cytogenetic characteristics of this invasive species, the objective of the present study was to investigate the basic and molecular cytogenetic characteristics of P. volitans in Venezuela, and compare the results with those from the original distribution area. For this, the karyotypic characteristics of four lionfish caught in Margarita Island, Venezuela, were investigated by examining metaphase chromosomes by Giemsa staining, C-banding, Ag-NOR, and two-colour-Fluorescent in situ hybridization (FISH) for mapping of 18S and 5S ribosomal genes. Comparing the sequences of the 16S gene of the specimens analyzed, with sequences already included in the Genbank, we corroborated that our specimens identified as P. volitans are in fact this species, and hence exclude the possibility of a misidentification of P. miles. The diploid number was 2n = 48 (2m + 10sm + 36a) with FN = 60. Chromosomes uniformly decreased in size, making it difficult to clearly identify the homologues except for the only metacentric pair, and the pairs number two, the largest of the submetacentric series. C-banding revealed only three pairs of chromosomes negative for C-band, whereas all remaining chromosomes presented telomeric and some interstitial C-positive blocks. Only two chromosomes were C-banding positive at the pericentromeric regions. Sequential staining revealed Ag-NOR on the tips of the short arms of chromosome pair number two and the FISH
A revision of the Larainae (Coleoptera, Elmidae) of Venezuela, with description of nine new species
Maier, Crystal A.
Abstract The species of the riffle beetle subfamily Larainae occurring in Venezuela are revised. Examination of 756 specimens yielded 22 species in nine genera occurring throughout the country. Seven species are newly recorded from the country: Phanoceroides sp. 1, Phanocerus clavicornis Sharp, 1882, Phanocerus congener Grouvelle, 1898, Pharceonus volcanus Spangler & Santiago-Fragoso, 1992, Disersus dasycolus Spangler & Santiago-Fragoso, 1992, Disersus chibcha Spangler & Santiago-Fragoso, 1987, and Disersus inca Spangler & Santiago-Fragoso, 1992. Nine species are found to be new to science, which are here described: Hexanchorus dentitibialis sp. n., H. falconensis sp. n., H. flintorum sp. n., H. homaeotarsoides sp. n., H. inflatus sp. n., Phanocerus rufus sp. n., Pharceonus grandis sp. n., Pharceonus ariasi sp. n., Potamophilops bostrychophallus sp. n. Additionally, a key to species, distribution maps, and photographs and genitalia illustrations are provided for all species. PMID:24146552
First report of metallo-β-lactamases producing Enterobacter spp. strains from Venezuela.
Martínez, Dianny; Rodulfo, Hectorina E; Rodríguez, Lucy; Caña, Luisa E; Medina, Belkis; Guzman, Militza; Carreño, Numirin; Marcano, Daniel; De Donato, Marcos
Clinical strains of Enterobacter were isolated from Cumana's Central Hospital in Venezuela, and classified as E. cloacae (21), E. aerogenes (7), E. intermedium (1), E. sakazakii (1) and three unclassified. The strains showed high levels of resistance, especially to SXT (58.1%), CRO (48.8%), CAZ (46.6%), PIP (46.4%), CIP (45.2%) and ATM (43.3%). This is the first report for South America of blaVIM-2 in two E. cloacae and one Enterobacter sp., which also showed multiple mechanisms of resistance. Both E. cloacae showed blaTEM-1, but only one showed blaCTX-M-15 gene, while no blaSHV was detected. PMID:24553611
The geothermal area of El Pilar-Casanay, State of Sucre, Venezuela: Geochemical exploration and model
D'Amore, F.; Gianelli, G.; Corazza, E. . Istituto Internazionale Ricerche Geotermiche)
A geochemical survey was carried out in the El Pilar-Casanay area, State of Sucre, Venezuela, in order to ascertain its geothermoelectric potential. The area is characterized by many natural manifestations with temperatures in the range 80--100 C. The area investigated seems capable of producing high-enthalpy geothermal fluids; a deep reservoir is inferred, composed of a medium salinity (< 5,000 ppm) and neutral brine, with computed temperatures between 250 and 300 C, and with a high CO[sub 2] partial pressure. Second shallower reservoir is assumed to exist, with a temperature of the order of 200--220 C. The deep reservoir is shown to be liquid-dominated, while water and steam occupy the shallow one. The piezometric level (elevation 150 m) regulates the areal distribution of water springs and fumaroles. A partial self-sealing (mineral alteration) along outflows allows accumulation of hot fluids, while recharge is from local meteoric water.
Cretaceous and Tertiary palynology used in the geological understanding of the Maturin sub-basin, Venezuela
Paredes, I.; Fasola, A. )
The use of palynology and micropaleontology, two biostratigraphic tools used at Intevep, S.A., have been of great help in the geological understanding during studies done on cores of the Maturin subbasin, a foreland type basin in Eastern Venezuela. Basically, the palynological work consisted of palynological and palynofacies analysis used to determine ages and to interpret the paleoenvironments of deposition in comparison with the interpretations obtained through sedimentological and micropaleontological studies. Palynomorph assemblages and palynofacies are shown for the quiescent Late Cretaceous, for the Tertiary in sequences that are not exactly dated and probably represent the first compressive movements in the basin, and for the Oligocene. In general, in these sequences it was possible to determine marine environments varying from near-shore to inner neritic, and also subaereal paleosols in the Cretaceous. The work highlights the importance of multidisciplinary studies in order to obtain interpretations more in accordance with reality.
Altitude determination and descriptive analysis of clouds on ERTS-1 multispectral photography. [Venezuela
NASA Technical Reports Server (NTRS)
Albrizzio, C.; Andressen, A.
A simple method to determine the approximate altitude of clouds is described, with the objective of refining their classification using only marginal data from the photographs. Results of the application of this method on photographs of the Goajira Peninsula, Paraguana Peninsula and the Central Coast of Venezuela are presented. Here, the altitudes computed are used to classify clouds and to identify the genus of others without typical form. Instability of air masses through clouds vertical development, and wind direction as well as other local climatic characteristics such as moisture content, loci of condensation, area, etc. are determined using repetitive coverage for the time interval of the photography. Applications for the regional and urban planning (including airport location and flights schedule) and natural resources evaluation are suggested.
FIRST REPORT OF METALLO-β-LACTAMASES PRODUCING Enterobacter spp. STRAINS FROM VENEZUELA
Martínez, Dianny; Rodulfo, Hectorina E.; Rodríguez, Lucy; Caña, Luisa E.; Medina, Belkis; Guzman, Militza; Carreño, Numirin; Marcano, Daniel; Donato, Marcos De
Clinical strains of Enterobacter were isolated from Cumana's Central Hospital in Venezuela, and classified as E. cloacae (21), E. aerogenes (7), E. intermedium (1), E. sakazakii (1) and three unclassified. The strains showed high levels of resistance, especially to SXT (58.1%), CRO (48.8%), CAZ (46.6%), PIP (46.4%), CIP (45.2%) and ATM (43.3%). This is the first report for South America of bla VIM-2 in two E. cloacae and one Enterobacter sp., which also showed multiple mechanisms of resistance. Both E. cloacae showed bla TEM-1, but only one showed bla CTX-M-15 gene, while no bla SHV was detected. PMID:24553611
A revision of the Larainae (Coleoptera, Elmidae) of Venezuela, with description of nine new species.
Maier, Crystal A
The species of the riffle beetle subfamily Larainae occurring in Venezuela are revised. Examination of 756 specimens yielded 22 species in nine genera occurring throughout the country. Seven species are newly recorded from the country: Phanoceroides sp. 1, Phanocerus clavicornis Sharp, 1882, Phanocerus congener Grouvelle, 1898, Pharceonus volcanus Spangler & Santiago-Fragoso, 1992, Disersus dasycolus Spangler & Santiago-Fragoso, 1992, Disersus chibcha Spangler & Santiago-Fragoso, 1987, and Disersus inca Spangler & Santiago-Fragoso, 1992. Nine species are found to be new to science, which are here described: Hexanchorus dentitibialis sp. n., H. falconensis sp. n., H. flintorum sp. n., H. homaeotarsoides sp. n., H. inflatus sp. n., Phanocerus rufus sp. n., Pharceonus grandis sp. n., Pharceonus ariasi sp. n., Potamophilops bostrychophallus sp. n. Additionally, a key to species, distribution maps, and photographs and genitalia illustrations are provided for all species. PMID:24146552
GPS-derived slip rates of active faults in eastern Venezuela, along the southeastern Caribbean PBZ
NASA Astrophysics Data System (ADS)
Audemard, F. A.; Beck, C.; Jouanne, F.; Reinoza, C. E.; Fegag
For over 20 years, GPS campaign measurements have been performed in eastern Venezuela, as well as in other areas of the country, by different scientific groups and in the frame of different either national or international efforts and/or projects, essentially aiming at the estimation of the rate of motion along the major Quaternary faults (i.e., Boconó, San Sebastián and El Pilar faults) composing the plate boundary zone (PBZ) between the Caribbean and South America, along onshore northern and western Venezuela. The slip rates and sense of slip of those major faults derived from the comparison of several GPS campaigns carried out through the years have confirmed the slip data (fault kinematics) previously derived from geologic data, through comprehensive neotectonic and paleoseismic studies mainly made by the FUNVISIS' Earth Sciences Dpt. staff. In a rough way, we could conclude that those faults are dextrally moving at a rate in the order of 10-12 mm/a. More recently, it has been shown that the El Pilar fault has a locking depth close to 10 km deep and that about half of the PBZ dextral motion is accommodated as creep, reducing the seismic hazard for northeastern Venezuela almost by half. On the contrary, in the near past, very little attention has been paid to the secondary active faulting in eastern Venezuela. In that sense, FUNVISIS, in collaboration with the Université de Savoie, started the monitoring of these secondary features by installing 36 brass benchmarks on bedrock in that region in 2003, which have been occupied 3 times, in late 2003 and 2005 and in early 2013. The comparison between the 2003 and 2005 occupations shows promising results, such as: a) The Charagato fault on Cubagua island is left-lateral with a slip rate of about 2 mm/a; b) slip vectors across the El Pilar fault tend to head to the ESE, suggesting that the tectonic regime is compressive transcurrent to transcurrent compressional (transpressional); c) The NW-SE-trending San Francisco
Reliability as the big persuader to privatize the electrical system in Venezuela
Alvarez B., C.E.
Throughout the past five years, the Venezuelan authorities, especially the Fondo de Inversiones de Venezuela (FIV), have done a major effort to privatize many of the state owned industries, among them, the electrical public utilities and some important electrical power generation plants or systems based on thermal generation. Mainly along the recent past years, black and brownouts have become more frequent in the system. In other words, system reliability has been diminishing, as a consequence of investment capital and O and M expenses have been reduced to levels below the required by the system. Public opinion is exercising pressure on politicians, so signals are that Congress will probably approve during the current or beginning of next years the required laws to expedite privatization and assure incentives and guaranties to investors. This paper deals with the insides of all these aspects, and with how soon privatization will be carried out. The FIV has been committed to implement this process.
Applied geointegration to hydrocarbon exploration in the San Pedro-Machango Area, Maracaibo Basin, Venezuela
Fonseca, A.; Navarro, A.; Osorio, R.; Corvo, F.; Arismendi, J.
Hydrocarbon exploration has nowadays a diversity of technological resources to capture, merge and interpret information from diverse sources. To accomplish this, the integration of geodata for modeling was done through the use of new technologies like Remote Sensing and Geographical Systems of Information and applied to the San Pedro-Machango area, located in the Serrania de Trujillo, west of Costa Bolivar (onshore), eastern Maracaibo Basin, Venezuela. The main purpose of this work was to optimize the design of an exploration program in harmony with environmental conservation procedures. Starting with satellital and radar images that incorporated geophysical, geological and environmental information, they then were analyzed and merged to improve the lithological, structural and tectonic interpretation, generating an integrated model that allowed better project design. The use of a system that combines information of geographical, geodetical, geophysical and geological origins with satellital and radar images produced up to date cartography and refined results of image interpretation.
AVO in North of Paria, Venezuela: Gas methane versus condensate reservoirs
Regueiro, J.; Pena, A.
The gas fields of North of Paria, offshore eastern Venezuela, present a unique opportunity for amplitude variations with offset (AVO) characterization of reservoirs containing different fluids: gas-condensate, gas (methane) and water (brine). AVO studies for two of the wells in the area, one with gas-condensate and the other with gas (methane) saturated reservoirs, show interesting results. Water sands and a fluid contact (condensate-water) are present in one of these wells, thus providing a control point on brine-saturated properties. The reservoirs in the second well consist of sands highly saturated with methane. Clear differences in AVO response exist between hydrocarbon-saturated reservoirs and those containing brine. However, it is also interesting that subtle but noticeable differences can be interpreted between condensate-and methane-saturated sands. These differences are attributed to differences in both in-situ fluid density and compressibility, and rock frame properties.
Management of a giant deep field: El Furrial Field, Eastern Venezuela
Pinto, N.; Mengual, R.; Anz, J.; Rodney, C.
The Furrial Field is located in Eastern Venezuela and produces a 25 to 30{degrees} API asphaltenic crude oil from a 1500 ft thick Oligocene sand interval at a depth of 15,000 ft. The bubble point is about 4500 psi as compared to an original pressure of 11,000 psi. Oil in place is approximately 6800 million STB. Currently production is 350 MB/D from 77 well streams (Naricual Formation), and water is being injected at 400 MB/D to maintain pressure. The combination of a volumetric reservoir and asphaltenic nature of crude oil resulted in a rapid decrease in well productivity and reservoir pressure, creating the necessity to maintain reservoir pressure to maximize recovery. Discussed in this paper are the reservoir management techniques and strategies used by Lagoven to develop and operate these complex reservoirs. Acquisition and analysis of these data adequate to properly implement these management techniques are covered in detail.
Methodology to incorporate EIA in land-use ordering -- case study: The Cataniapo River basin, Venezuela
Sebastiani, M.; Llambi, L.D.; Marquez, E.
In Venezuela, the idea of tiering information between land-use ordering instruments and impact assessment is absent. In this article the authors explore a methodological alternative to bridge the information presented in land-use ordering instruments with the information requirements for impact assessment. The methodology is based on the steps carried out for an environmental impact assessment as well as on those considered to develop land-use ordering instruments. The methodology is applied to the territorial ordering plan and its proposal for the protection zone of the Cataniapo River basin. The purpose of the protection zone is to preserve the water quality and quantity of the river basin for human consumption.
Trypanosoma cruzi, the Causal Agent of Chagas Disease: Boundaries between Wild and Domestic Cycles in Venezuela
Herrera, Leidi
Trypanosoma cruzi the etiological agent of American Trypanosomiasis or Chagas disease (ChD) is transmitted by triatomines vectors between mammals including man. T. cruzi has existed for circa 150 Ma in the Americas and nearly 10 million people are currently infected. The overlap between wild and domestic ecotopes where T. cruzi circulates is increasing. Host–parasite interactions have been determined by infection patterns in these cycles, all under natural or laboratorial conditions. This mini-review describes specific parasite niches, such as plant communities or biological corridors between domestic and wild landscapes, in order to help identify risk factors for ChD and define the boundaries between wild and domestic transmission cycles, with an emphasis on research undertaken in Venezuela. PMID:25506587
Envenomation by neotropical opisthoglyphous colubrid Thamnodynastes cf. pallidus Linne, 1758 (Serpentes:Colubridae) in Venezuela.
Diaz, Fresnel; Navarrete, Luis F; Pefaur, Jaime; Rodriguez-Acosta, Alexis
This is a case report of a "non-venomous" snake bite in a herpetologist observed at the Sciences Faculty of the Universidad de los Andes (Mérida, Venezuela). The patient was bitten on the middle finger of the left hand, and shows signs of pronounced local manifestations of envenomation such as bleeding from the tooth imprint, swelling and warmth. He was treated with local care, analgesics, and steroids. He was dismissed from the hospital and observed at home during five days with marked improvement of envenomation. The snake was brought to the medical consult and identified as a Thamnodynastes cf. pallidus specimen. This report represents the first T. pallidus accident described in a human. PMID:15517037
CTX-M-14 β-lactamase-producing Citrobacter freundii isolated in Venezuela
A clinical isolate of C. freundii with reduced susceptibility to extended-spectrum β-lactams from a woman with cystocele associated with recurrent urinary tract infection was analyzed. Susceptibility tests, double disk synergy tests (DDST) and enzymatic activity by the agar iodometric method suggested the presence of ESBLs. Conjugation experiments revealed the presence of a large conjugative plasmid (pLM07/20) with an exclusive FrepB replicon type (IncF/FIB). PCR analysis and sequencing confirmed the presence of the blaCTX-M-14 gene in the pLM07/20 from C. freundii.LM07/10. Although this is the first report of CTX-M-14 in Venezuela, we alert the medical community that future increase of these β-lactamases in our city could be due to dissemination of plasmids into bacterial populations. PMID:21627834
Methane production from mixed tropical savanna and forest vegetation in Venezuela
NASA Astrophysics Data System (ADS)
Crutzen, P. J.; Sanhueza, E.; Brenninkmeijer, C. A. M.
Measurements of methane concentrations in the boundary layer in the northern part of the Guayana shield, Venezuela, during the wet season (October 1988), showed the presence of substantial methane surface emissions. The measuring site is within the savanna climate region, but is affected by emissions from savanna and forest vegetation. From day versus night concentration measurements, with higher concentrations during night, a methane source strength near the site of 3-7×1011 molecules/cm2/s can be estimated, which includes emissions from small tracts of flooded soils, termites and especially tropical vegetation. Extrapolated to the entire savanna, this may imply a methane source of ~30-60 Tg yr-1 similar to the one calculated for tropical vegetation on the basis of recently published in vitro plant emission experiments by Keppler et al. (2006), which indicate emissions of ~30 Tg yr-1 for tropical savannas and grasslands and ~78 Tg yr-1 for tropical forests.
Sedimentological Signatures of Transient Depositional Events in the Cariaco Basin, Venezuela
NASA Astrophysics Data System (ADS)
Elmore, A. C.; Thunell, R. C.; Black, D. E.; Murray, R. W.; Martinez, N. C.
The varved sediments that have accumulated in the Cariaco Basin throughout the Holocene provide a detailed archive of the region's climatic history, and act as a historical record for the occurrence of phenomena such as earthquakes and coastal flooding. In this study we compare the sedimentological characteristics of lithogenic material collected from the water column during transient depositional events to those of normal hemipelagic sedimentation in the basin. Specifically, we have examined the clay mineralogy and grain size distribution of detrital material delivered to the basin by the July 9, 1997 earthquake near Cumana, Venezuela and the coastal flooding of Venezuela in late 1999. The sample material used in our study was collected as part of an ongoing sediment trap time series in the Cariaco Basin. The sedimentological signatures associated with these two events are distinctive from the typical lithogenic input to the basin. Preliminary data for biweekly samples collected from 1997-1999 shows a tri-modal particle size distribution, with peaks at 3, 22, and 80 im. However, material collected from the deep basin immediately following the 1997 earthquake is characterized by a particle diameter distribution at 6 and 22 im with a smaller than normal peak at 80 im; this variance suggests an alternate source of material was delivered to the basin via a turbidity flow induced by the earthquake. Supporting this theory, the clay mineralogy of the same sediment trap samples shows a higher than average ratio of kaolinite to quartz for sediments delivered to the basin following both the earthquake and flooding. We hope to extend the use of these sedimentological methods to identify past transient depositional events in Cariaco Basin cores.
Evidence of at Least Two Introductions of HIV-1 in the Amerindian Warao Population from Venezuela
Rangel, Héctor R.; Maes, Mailis; Villalba, Julian; Sulbarán, Yoneira; de Waard, Jacobus H.; Bello, Gonzalo; Pujol, Flor H.
Background The Venezuelan Amerindians were, until recently, free of human immunodeficiency virus (HIV) infection. However, in 2007, HIV-1 infection was detected for the first time in the Warao Amerindian population living in the Eastern part of Venezuela, in the delta of the Orinoco river. The aim of this study was to analyze the genetic diversity of the HIV-1 circulating in this population. Methodology/Principal Findings The pol genomic region was sequenced for 16 HIV-1 isolates and for some of them, sequences from env, vif and nef genomic regions were obtained. All HIV-1 isolates were classified as subtype B, with exception of one that was classified as subtype C. The 15 subtype B isolates exhibited a high degree of genetic similarity and formed a highly supported monophyletic cluster in each genomic region analyzed. Evolutionary analyses of the pol genomic region indicated that the date of the most recent common ancestor of the Waraos subtype B clade dates back to the late 1990s. Conclusions/Significance At least two independent introductions of HIV-1 have occurred in the Warao Amerindians from Venezuela. The HIV-1 subtype B was successfully established and got disseminated in the community, while no evidence of local dissemination of the HIV-1 subtype C was detected in this study. These results warrant further surveys to evaluate the burden of this disease, which can be particularly devastating in this Amerindian population, with a high prevalence of tuberculosis, hepatitis B, among other infectious diseases, and with limited access to primary health care. PMID:22808212
[Distribution and density of two holothurian species in Cubagua Island, Venezuela].
Tagliafico, Alejandro; Rangel, María Salomé; Rago, Néstor
Holothurian populations in the Caribbean have been significantly depleted in some areas, and others are still in danger to satisfy international markets. In Venezuela, this marine resource has been illegally exploited since the early 1990s. To contribute with their management and protection, this work analyzed the distribution, abundance and population structure of two commercial holothurians Isostichopus badionotus and Holothuria mexicana in Cubagua Island shores. A total of 52 stations were studied around the island during the year 2008. Surveys included visits to each station, for which a band transect of 50 m2 with four replicates were carried out. The results show that I. badionotus has a higher distribution on the East coast of the island, and is found over Thalassia testudinum beds or bivalve molluscs aggregations, with an average density of 0.011 ind/m2, C.I. 95% = 0.005-0.017, n = 122, and a general abundance estimated in 117 ind/ha. H. mexicana has been practically depleted (0.001 ind/m2 C.I. 95% = 0.0002-0.0013, 7.7 ind/ha, n = 8). We recommend the maintenance of the total ban adopted in 1997 to assure the protection of these species, mainly because no previous data supported the start of the fishery, and also, because the current densities are still very low when compared to other areas in Venezuela and the Caribbean. These are animals easy to catch, susceptible to overfishing, and with a very low recovery rate; thus, more control is required from the local authorities. PMID:21721242
Eastern Venezuela Basin's Post-Jurassic evolution as a passive transform margin basin
George, R.P. Jr. ); Sams, R.H. )
Passive transform margins are segments of rifted continental margins bounded by transform faults that are active during rifting and that become inactive during drifting. Examples include the northern coast of Brazil and its matching margin along the Liberia-Nigeria coast. We propose that the northern margin of the Eastern Venezuela Basin was dominantly a passive transform margin during the Cretaceous and early Paleogene, rather than a purely passive margin. Published microplate reconstructions of the southern Caribbean show Jurassic separation of the Bahamas platform from northern South America along a northwest-trending transform fault postulated to lie just northeast of Trinidad and the Guianas. We conjecture that the [open quotes]Deflexion de Barcelona[close quotes] (a northwest-trending zone of strike slip faults along the southwestern edge of the Serrania del Interior) is controlled by a basement geofracture that is the onshore expression of Jurassic transform fault southwest of and subparallel to the southwestern Bahamas transform. Implications of this conjecture for the Eastern Venezuela Basin include: (1) absence of McKenzie-type regional crustal stretching, Mesozoic thermal anomaly, and Mesozoic thermal-tectonic subsidence; (2) abrupt rather than gradual seaward changes in crustal thickness; (3)abrupt lateral changes in thickness and facies of Mesozoic sediments, as in the Piaui-Ceara basins of northern Brazil; (4) tendency for structural styles developed during Neogene compression to include more strike-slip faults and en enchelon fold sets (because of reactivation of Mesozoic transforms) than would be expected by structural inversion of a purely passive margin.
Common Distribution Patterns of Marsupials Related to Physiographical Diversity in Venezuela
Ventura, Jacint; Bagaria, Guillem; Sans-Fuentes, Maria Assumpció; Pérez-Hernández, Roger
The aim of this study is to identify significant biotic regions (groups of areas with similar biotas) and biotic elements (groups of taxa with similar distributions) for the marsupial fauna in a part of northern South America using physiographical areas as Operational Geographical Units (OGUs). We considered Venezuela a good model to elucidate this issue because of its high diversity in landscapes and the relatively vast amount of information available on the geographical distribution of marsupial species. Based on the presence-absence of 33 species in 15 physiographical sub-regions (OGUs) we identified Operational Biogeographical Units (OBUs) and chorotypes using a quantitative analysis that tested statistical significance of the resulting groups. Altitudinal and/or climatic trends in the OBUs and chorotypes were studied using a redundancy analysis. The classification method revealed four OBUs. Strong biotic boundaries separated: i) the xerophytic zone of the Continental coast (OBU I); ii) the sub-regions north of the Orinoco River (OBU III and IV); and those south to the river (OBU II). Eleven chorotypes were identified, four of which included a single species with a restricted geographic distribution. As for the other chorotypes, three main common distribution patterns have been inferred: i) species from the Llanos and/or distributed south of the Orinoco River; ii) species exclusively from the Andes; and iii) species that either occur exclusively north of the Orinoco River or that show a wide distribution throughout Venezuela. Mean altitude, evapotranspiration and precipitation of the driest month, and temperature range allowed us to characterize environmentally most of the OBUs and chorotypes obtained. PMID:24806452
Characterization and distribution of tomato yellow margin leaf curl virus, a begomovirus from Venezuela.
Nava, A; Londoño, A; Polston, J E
A begomovirus causing mottling and leaf deformation in tomato from the State of Mérida was cloned and sequenced. The virus has a bipartite genome comprised of a DNA-A (2,572 nucleotides) and a DNA-B (2,543 nucleotides) with a genome organization typical of New World begomoviruses. Both components share a common region of 115 nucleotides with 98 % sequence identity. Phylogenetic analysis indicated that while no virus sequences were closely related, the A component was distantly related to those of two other tomato-infecting viruses, tomato leaf deformation virus and Merremia mosaic virus; and the DNA-B, to those of pepper huasteco yellow vein virus and Rhynchosia golden mosaic Yucatan virus. The DNA-A and DNA-B sequences were submitted to GenBank (accession no. AY508993 and AY508994, respectively) and later accepted by the International Committee on Taxonomy of Viruses as the genome of a member of a unique virus species with the name Tomato yellow margin leaf curl virus (TYMLCV). Tomato (Solanum lycopersicum L. 'Fl. Lanai') plants inoculated with cloned TYMLCV DNA-A and DNA-B became systemically infected and showed chlorotic margins and leaf curling. The distribution of TYMLCV in tomato-producing states in Venezuela was determined by nucleic acid spot hybridization analysis of 334 tomato leaf samples collected from ten states using a TYMLCV-specific probe and confirmed by PCR and sequencing of the PCR fragment. TYMLCV was detected in samples from the states of Aragua, Guárico, and Mérida, suggesting that TYMLCV is widely distributed in Venezuela. PMID:23064695
Integrated foraminiferal biostratigraphy and chemostratigraphy of the querecual formation (Cretaceous), Eastern Venezuela
Crespo De Cabrera, S.; Sliter, W.V.; Jarvis, I.
An integrated foraminiferal biostratigraphy and chemostratigraphy is presented for the Lower to Upper Cretaceous Querecual Formation exposed on Chimana Grande Island, Eastern Venezuela. The formation consists of >450 m alternating foraminiferal and organic-rich carbonates and laminated mudrocks, and is considered the main hydrocarbon source rock for the eastern Venezuela Basin. Biostratigraphic resolution within the Querecual Formation is poor, due to a paucity of keeled planktonic foraminifera and impoverished benthic faunas. Deposition occurred in a bathyal environment, with dysaerobic or anoxic bottom waters resulting from high rates of surface productivity associated with an upwelling environment. Biostratigraphic evidence indicates that the Querecual Formation ranges from the upper Albian Rotalipora ticinensis Zone to the Santonian Dicarinella asymetrica Zone. Iron and Al contents fall through the Albian-Cenomanian indicating a progressive decrease in the detrital supply, driven by rising eustatic sea level. A Ca profile demonstrates variations in carbonate production and dissolution. High total organic carbon (TOC) intervals occur in the upper Albian to mid-Cenomanian and Turonian, and high Ba/Al and Si/Al ratios characterize mid-Cenomanian and younger sediments. Variations in these elements primarily reflect changes in marine productivity, but are also affected by diagenetic processes. A stable carbon isotope curve established from analysis of organic matter (??13Corg) correlates well with published ??13C curves for carbonates from England and Italy. The Cenomanian/Turonian boundary cannot be identified using planktonic foraminifera, because key taxa are absent, but the base of the Turonian is clearly indicated by a sharp fall in ??13C immediately above a major positive excursion. The bottom of the Coniacian is placed below a ??13C minimum, towards the base of the Dicarinella concavata Zone. Combined with the foraminiferal data, the isotopic data enable much
Common distribution patterns of marsupials related to physiographical diversity in Venezuela.
Ventura, Jacint; Bagaria, Guillem; Sans-Fuentes, Maria Assumpció; Pérez-Hernández, Roger
The aim of this study is to identify significant biotic regions (groups of areas with similar biotas) and biotic elements (groups of taxa with similar distributions) for the marsupial fauna in a part of northern South America using physiographical areas as Operational Geographical Units (OGUs). We considered Venezuela a good model to elucidate this issue because of its high diversity in landscapes and the relatively vast amount of information available on the geographical distribution of marsupial species. Based on the presence-absence of 33 species in 15 physiographical sub-regions (OGUs) we identified Operational Biogeographical Units (OBUs) and chorotypes using a quantitative analysis that tested statistical significance of the resulting groups. Altitudinal and/or climatic trends in the OBUs and chorotypes were studied using a redundancy analysis. The classification method revealed four OBUs. Strong biotic boundaries separated: i) the xerophytic zone of the Continental coast (OBU I); ii) the sub-regions north of the Orinoco River (OBU III and IV); and those south to the river (OBU II). Eleven chorotypes were identified, four of which included a single species with a restricted geographic distribution. As for the other chorotypes, three main common distribution patterns have been inferred: i) species from the Llanos and/or distributed south of the Orinoco River; ii) species exclusively from the Andes; and iii) species that either occur exclusively north of the Orinoco River or that show a wide distribution throughout Venezuela. Mean altitude, evapotranspiration and precipitation of the driest month, and temperature range allowed us to characterize environmentally most of the OBUs and chorotypes obtained. PMID:24806452
[Superficial mycoses in patients from Anzoátegui state, Venezuela, period 2002-2012].
Lemus-Espinoza, Druvic; Teresa Maniscalchi, María; Villarroel, Oskarina; Bónoli, Stefano B; Wahab, Fadi; García, Oswaldo
Superficial fungal diseases that affect the skin and its appendages are frequently seen in basic triage and in dermatology services. These diseases are distributed in Venezuela with an incidence of 92.9%. The aim of this study was to determine the genera and species that cause dermatomycoses in residents of Anzoátegui state, Venezuela, during the period 2002-2012. A total of 4257 patients with a presumptive diagnosis of superficial mycoses were studied, with ages from 7 months to 79 years. The overall prevalence was 30.9%. The most frequent were dermatophytosis (44.7%). M. canis produced 148 cases of tinea capitis. Three dermatophytic agents represented 95% of all cases, with a significant predominance of T. mentagrophytes with 50%. Candidosis occurred in 28.4%. C. albicans, and the C. parapsilosis complex, were responsible for 80% of the cases. The other species identified were C. tropicalis (n = 41, 11.0%), C. glabrata (n = 10, 2.7%), C. guilliermondii (n = 6, 1.6%), C. krusei (n = 4, 1.1%). Pityriasis versicolor occurred in 22.4% of the cases studied, and less frequently were present onychomycosis produced by a non dermatophytic mold: Fusarium oxysporum (n = 34, 65.4%), Aspergillus terreus (n=16, 30.8%) and Scytalidium dimidiatum (n=2; 3.8%). Rare cases of Trichosporon onychomycosis (0.5%) and one case of black tinea were also found. Health education in the population is recommended to promote measures to prevent transmission of these fungi and prevent the spread of this silent public health problem. PMID:25558751
The Cerro Negro accumulation of Venezuela's Orinoco Belt - the favorable convergence of several geological processes
Swanson, D.C. ); Tarache, C. )
The Cerro Negro Area is a major part of eastern Venezuela's Orinoco Belt. Here upper Eocene fluvial-deltaic deposits of the Oficina Fm. reservoir billions of barrels of heavy oil, much of which is in valley-fill deposits. Maturation, migration and accumulation of these hydrocarbons in thick, porous and permeable sandstones were the logical conclusion to several major geological events in eastern Venezuela during the Tertiary. In the Cerro Negro Area, Cretaceous clastics were deposited on an igneous and metamorphic basement after which the sea withdrew northward toward the axial part of the Eastern Venezuelan Basin. The basement and Cretaceous deposits were weathered and eroded during the Eocene, Oligocene, and early Miocene, forming the unconformity on which the Oficina Fm. is deposited. Historic reconstruction begins with this unconformity, a paleotopographic surface strongly influencing the character and distribution of the overlying Oficina Fm. As relative sea level fell and gradients increased, streams incised into the shelf while transporting great amounts of coarse clastic load northward. At Cerro Negro, a mature topography of low ridges and hills were developed with differential elevations of several hundred feet. During the Miocene, a sea transgressed across the stream-etched unconformity. Streams carrying large amounts of clastic load encountered an elevating sea level. They consequently dropped their coarse load, forming long, linear, transgressive, valley-fill deposits. By Late Miocene, hydrocarbons generated in the deeper basin began to migrate southward through the long linear fluvial-deltaic clastic conduits that were separated laterally and vertically into complex [open quotes]plumbing systems.[close quotes] As the hydrocarbons moved shelfward, normal faults cut the conduits into numerous reservoir segments. The timing between migration and faulting is critical to present-day hydrocarbon distribution in these segments.
Environmental factors in Helicobacter pylori-related gastric precancerous lesions in Venezuela.
Kato, Ikuko; Vivas, Jorge; Plummer, Martyn; Lopez, Gladys; Peraza, Simon; Castro, Dennis; Sanchez, Victor; Cano, Elsa; Andrade, Olga; Garcia, Rita; Franceschi, Silvia; Oliver, Walter; Muñoz, Nubia
Although Helicobacter pylori (HP) infection has been acknowledged to play an etiological role in gastric carcinogenesis, its relatively weak association particularly in developing countries suggests critical roles of cofactors. Among a population with an extremely high prevalence of HP infection ( approximately 95%) in Venezuela, we examined the relationship of household characteristics, smoking, alcohol drinking, dietary consumption, and plasma nutrient levels with the prevalence of three different stages of gastric precancerous lesions, chronic atrophic gastritis (AG; n = 337), intestinal metaplasia (IM; n = 551), and dysplasia (n = 157), in comparison with those without any of these lesions (n = 1154). Length of refrigerator use was marginally inversely associated with the prevalence of the precursor lesions studied. The association was most pronounced for AG followed by dysplasia. On the other hand, smoking status was a significant predictor for IM and dysplasia. Those smoking >/=>10 cigarettes/day had 1.8-fold risk of IM and 3.6-fold risk of dysplasia compared with never smokers. There were no associations with alcohol consumption. When six food groups known to be associated with stomach cancer risk in Venezuela were tested, the prevalence of these lesions progressively increased with increasing starchy vegetable consumption and decreasing fresh fruit/fruit juice consumption. The association with fruits was more evident for dysplasia and AG and that with starchy vegetables for IM and AG. However, there were no inverse associations with plasma antioxidant vitamins. These findings offer important public health implications in preventing progression of HP-associated gastric precancerous lesions in high-risk populations. PMID:15006925
ALTA: An automated lag-time apparatus for studying the nucleation of supercooled liquids
NASA Astrophysics Data System (ADS)
Barlow, Thomas W.; Haymet, A. D. J.
An automated apparatus for studying repeatedly the nucleation of a sample of supercooled liquid is designed and constructed. Many of the ideas are developed from an apparatus of M. Baldwin and B. Vonnegut [Rev. Sci. Instrum. 53, 1911 (1982)]. After preparation of a nonequilibrium state, ALTA measures repeatedly the ``lag time'' or ``induction'' time before nucleation and growth of the equilibrium state. A single sample is used in all experiments. The operation of the apparatus is demonstrated by generating a time series of lag times for the nucleation of supercooled water on (insoluble) AgI crystals at the temperature 269.2 K. The same sample is repeatedly frozen and thawed over 350 times. An average lag time τ can be measured precisely and reproducibly. However, nucleation of this sample is shown to be a stochastic process obeying ``first-order'' kinetics. Improved methods for analyzing time series of nucleation data are presented and tested.
Geologic and hydrologic data collected at test hole NC-8, Vega Alta, Puerto Rico
Rodríguez-Martínez, Jesús; Scharlach, Richard A.
Test hole NC-8 was drilled in the municipality of Vega Alta as part of a study of the aquifers in the Northern Coastal Province of Puerto Rico. Test hole NC-8 was drilled to a depth of 1,736 feet below land surface. Geologic and hydrologic data collected during drilling included continuous core, water- quality samples, water-level measurements, and estimates of aquifer yields from the water-bearing zones. Test hole NC-8 penetrated five geologic formations of middle Tertiary age: the Aymamon Limestone, the Los Puertos Formation, the Cibao Formation, the Lares Limestone, and the San Sebastian Formation. Test hole NC-8 penetrated a water-table aquifer and seven artesian aquifers.
[The prevention of caries in Alta Val di Cecina--Volterra: a longitudinal study].
Benetti, G L; Dini, M; Rossetti, L
The authors present the results of three years' activity relating to "caries' prevention" in comparison with data concerning the research of previous five years. The average and standard deviations of DMFT values with regard to the permanent teeth and dmft concerning the deciduous ones, obtained from the dental visit of 222 children attending the 1st and the 3rd class of the primary school and 1st class of the secondary school, has demonstrated a statistically significant reduction of caries, compared with data concerning 749 pupils of the same standards in the period from 1984 to 1988. This fact confirms that the programme defined by U.S.L. n. 15 "Alta Val di Cecina", including sanitary education for children of primary school with their parents and teachers, besides dental examinations to the filter classes, is a valid instrument to obtain the reduction of carious' pathology in evolutive age. PMID:8265461
Performance of the ALTA 4700 with variable print strategy and optimized resist process
NASA Astrophysics Data System (ADS)
Allen, Paul C.; Hamaker, H. Christopher; Morgante, Cris; Berwick, Andrew; White, Michael
The ALTA 4700 incorporates new optical subsystems to improve pattern quality performance and has added the capability to do variable multipass printing. The optical system changes are the addition of a 0.9-NA reduction lens and a new AOD subsystem to reduce beam placement and intensity errors. Variable multipass printing allows two-, four- or eight-pass printing, thereby enabling the user to optimize the pattern quality/throughput tradeoff. Local CDU 3σ performance for one pattern is reduced from 8.2 to 5.1 to 3.4 nm as the number of passes is increased from two to four to eight. Reduction of CDU performance is more pattern dependent going from four to eight passes than going from two to four passes. Pattern write times scale roughly linearly with the number of passes. Local pattern loading effects can limit global CDU performance. These effects can be reduced by optimizing resist selection and develop processes.
[Diatoms from Unare and Píritu Lagoons, Anzoátegui state, Venezuela. Subclass Bacillariophycidae D. G. Mann ].
Subero-Pino, Sonia S; Diaz-Ramos, José R; Sanchez-Suarez, Isaac G; Ferraz-Reyes, Elvira
The diatom flora of Unare and Píritu Lagoons, Venezuela, comprises freshwater, estuarine and marine organisms. In this paper, 15 species of diatoms belonging to the subclass Bacillariophyceae D.G. Mann are described. Water samples from Unare and Píritu lagoons (Venezuela) were collected from November 1988 to July 1989. Samples were fixed with neutral formaldehyde (10%) and were examined under phase contrast microscopy. Species under study were Dictyoneis marginata (Lewis) Cleve, Cymbella affinis (Kützing) Cleve, Cymbella sp., Achnanthes brevipes var. intermedia (Kützing) Cleve, Lyrella irroratoides (Hustedt) Mann, Navicula carinifera (Grunow) Peragallo, Navicula liber (W. Smith) Peragallo, Navicula vacillans (Schmidt) Peragallo, Navicula sp, Amphora crassa var. campechiana Grunow, Amphora decussata Grunow, Caloneis powelli (Lewis) Cholnoky, Tryblionella acuta (Cleve) Mann in Round et al., Tryblionella apiculata Gregory, Surirella febigerii Lewis. PMID:12216503
[Embrionary and larval development of Lytechinus variegatus (Echinoidea: Toxopneustidae) in laboratory conditions at Isla de Margarita-Venezuela].
Gómez, Olga; Gómez, Alfredo
The sea urchin Lytechinus variegatus is a promissory species for aquaculture activities in tropical countries. In Venezuela, this species has some economical importance but their embryonic and larval development had not been studied. We collected specimens from seagrass beds in Margarita Island (Venezuela) and kept them in the laboratory, where they spawned naturally. With filtered sea water (temperature 28 degrees C, salinity 37 psu) and moderate aeration, the eggs and sperm were mixed (relation 1:100) and reached a 90% fertilization rate. The fertilization envelope was observed after two minutes, the first cellular division after 45 minutes and the prism larval stage after 13 hours. The echinopluteus larval stage was reached after 17 hours and metamorphosis after 18 days of planktonic life, when the larvae start their benthic phase. PMID:17469261
Source investigation of two outbreaks of skin and soft tissue infection by Mycobacterium abscessus subsp. abscessus in Venezuela.
Torres-Coy, J A; Rodríguez-Castillo, B A; Pérez-Alfonzo, R; DE Waard, J H
Outbreaks of soft tissue or skin infection due to non-tuberculous mycobacteria are reported frequently in scientific journals but in general the infection source in these outbreaks remains unknown. In Venezuela, in two distinct outbreaks, one after breast augmentation surgery and another after hydrolipoclasy therapy, 16 patients contracted a soft tissue infection due to Mycobacterium abscessus subsp. abscessus. Searching for the possible environmental infection sources in these outbreaks, initially the tap water (in the hydrolipoclasy therapy outbreak) and a surgical skin marker (in the breast implant surgery outbreak), were identified as the infection sources. Molecular typing of the strains with a variable number tandem repeat typing assay confirmed the tap water as the infection source but the molecular typing technique excluded the skin marker. We discuss the results and make a call for the implementation of stringent hygiene and disinfection guidelines for cosmetic procedures in Venezuela. PMID:26441024
HIV prevalence, sexual behaviours and engagement in HIV medical care among an online sample of sexually active MSM in Venezuela.
Perez-Brumer, Amaya G; Oldenburg, Catherine E; Biello, Katie B; Novak, David S; Rosenberger, Joshua G; Mimiaga, Matthew J
In Venezuela, members of a social and sexual partner networking site for men who have sex with men (MSM) completed an online survey regarding sexual behaviours and HIV medical care. Among the 2851 respondents, self-reported HIV prevalence was 6.6%. Of participants living with HIV, 73.2% reported taking antiretroviral medication and 56.6% reported complete adherence within the past month. Participants living with HIV were more likely to be older (aOR = 1.04 per one-year increase in age, 95% CI: 1.02, 1.06) and diagnosed with a sexually transmitted infection in the previous year (aOR 3.26, 95% CI: 2.11, 5.04). These data provide further understanding of the HIV epidemic among MSM in Venezuela, and potential targets for HIV prevention interventions. PMID:26378188
Development of an Unnatural Amino Acid Incorporation System in the Actinobacterial Natural Product Producer Streptomyces venezuelae ATCC 15439.
He, Jingxuan; Van Treeck, Briana; Nguyen, Han B; Melançon, Charles E
Many Actinobacteria, most notably Streptomyces, produce structurally diverse bioactive natural products, including ribosomally synthesized peptides, by multistep enzymatic pathways. The use of site-specific genetic incorporation of unnatural amino acids to investigate and manipulate the functions of natural product biosynthetic enzymes, enzyme complexes, and ribosomally derived peptides in these organisms would have important implications for drug discovery and development efforts. Here, we have designed, constructed, and optimized unnatural amino acid systems capable of incorporating p-iodo-l-phenylalanine and p-azido-l-phenylalanine site-specifically into proteins in the model natural product producer Streptomyces venezuelae ATCC 15439. We observed notable differences in the fidelity and efficiency of these systems between S. venezuelae and previously used hosts. Our findings serve as a foundation for using an expanded genetic code in Streptomyces to address questions related to natural product biosynthesis and mechanism of action that are relevant to drug discovery and development. PMID:26562751
Vector competence of Simulium metallicum s.l. (Diptera: Simuliidae) in two endemic areas of human onchocerciasis in northern Venezuela.
Grillet, M E; Botto, C; Basañez, M G; Barrera, R
Experimental infections of Simulium metallicum s.l. with Onchocerca volvulus were carried out in two onchocerciasis foci, Altamira and Trincheras, in northern Venezuela, to determine vector competence. Wild-caught flies, fed on infected volunteers, were maintained in the laboratory for 13-15 days at 27 degrees C. Parasite development was complete but asynchronous and retarded. No differences in the vector competence of the two populations of S. metallicum s.l. were found. However, a less efficient development of the parasite occurred during the dry season at both localities. The distribution of the parasite within the vector was aggregated and also displayed seasonal variation. The seasonal susceptibility may be a consequence of a density-dependence regulation mechanism of the parasite within the vector. These results indicate a relatively low vector competence for S. metallicum s.l. in northern Venezuela. PMID:8192518
Alta Scuola Politecnica: An Ongoing Experiment in the Multidisciplinary Education of Top Students towards Innovation in Engineering, Architecture and Design
ERIC Educational Resources Information Center
Benedetto, S.; Bernelli Zazzera, F.; Bertola, P.; Cantamessa, M.; Ceri, S.; Ranci, C.; Spaziante, A.; Zanino, R.
Politecnico di Milano and Politecnico di Torino, the top technical universities in Italy, united their efforts in 2004 by launching a unique excellence programme called Alta Scuola Politecnica (ASP). The ASP programme is devoted to 150 students, selected each year from among the top 5-10% of those enrolled in the Engineering, Architecture and…
A new species and new records of Pseudocephennium Reitter in Venezuela, with notes on movable endophallic structures (Coleoptera: Staphylinidae: Scydmaeninae).
Jałoszyński, Paweł
Pseudocephennium auriculatum sp. n. is described, based on a male specimen collected in north-western Venezuela. New findings of Pseudocephennium maximum Jałoszyński and P. araguanum Jałoszyński, so far known only from holotypes, are reported. The aedeagi of newly found specimens have the endophallic structures extruded to various extent which makes it possible to identify movable components of the internal aedeagal armature. PMID:27394359
Molecular epidemiology suggests Venezuela as the origin of the dengue outbreak in Madeira, Portugal in 2012-2013.
Franco, L; Pagan, I; Serre Del Cor, N; Schunk, M; Neumayr, A; Molero, F; Potente, A; Hatz, C; Wilder-Smith, A; Sánchez-Seco, M P; Tenorio, A
An explosive epidemic occurred in Madeira Island (Portugal) from October 2012 to February 2013. Published data showed that dengue virus type 1 introduced from South America was the incriminated virus. We aim to determine the origin of the strain introduced to Madeira by travellers returning to Europe. Using phylogeographic analysis and complete envelope sequences we have demonstrated that the most probable origin of the strain is Venezuela. PMID:25843502
Global Climate Change Effects on Venezuela's Vulnerability to Chagas Disease is Linked to the Geographic Distribution of Five Triatomine Species.
Ceccarelli, Soledad; Rabinovich, Jorge E
We analyzed the possible effects of global climate change on the potential geographic distribution in Venezuela of five species of triatomines (Eratyrus mucronatus (Stal, 1859), Panstrongylus geniculatus (Latreille, 1811), Rhodnius prolixus (Stål, 1859), Rhodnius robustus (Larrousse, 1927), and Triatoma maculata (Erichson, 1848)), vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. To obtain the future potential geographic distributions, expressed as climatic niche suitability, we modeled the presences of these species using two IPCC (Intergovernmental Panel on Climate Change) future emission scenarios of global climate change (A1B and B1), the Global Climate model CSIRO Mark 3.0, and three periods of future projections (years 2020, 2060, and 2080). After estimating with the MaxEnt software the future climatic niche suitability for each species, scenario, and period of future projections, we estimated a series of indexes of Venezuela's vulnerability at the county, state, and country level, measured as the number of people exposed due to the changes in the geographical distribution of the five triatomine species analyzed. Despite that this is not a measure of the risk of Chagas disease transmission, we conclude that possible future effects of global climate change on the Venezuelan population vulnerability show a slightly decreasing trend, even taking into account future population growth; we can expect fewer locations in Venezuela where an average Venezuelan citizen would be exposed to triatomines in the next 50-70 yr. PMID:26336258
Natural hazards on alluvial fans: the debris flow and flash flood disaster of December 1999, Vargas state, Venezuela
Larsen, Matthew C.; Wieczorek, Gerald F.; Eaton, L.S.; Torres-Sierra, Heriberto
Large populations live on or near alluvial fans in locations such as Los Angeles, California, Salt Lake City, Utah, Denver, Colorado, and lesser known areas such as Sarno, Italy, and Vargas, Venezuela. Debris flows and flash floods occur episodically in these alluvial fan environments, and place many communities at high risk during intense and prolonged rainfall. In December 1999, rainstorms induced thousands of landslides along the Cordillera de la Costa, Vargas, Venezuela. Rainfall accumulation of 293 mm during the first 2 weeks of December was followed by an additional 911 mm of rainfall on December 14 through 16. Debris flows and floods inundated coastal communities resulting in a catastrophic death toll of as many as 30,000 people. Flash floods and debris flows caused severe property destruction on alluvial fans at the mouths of the coastal mountain drainage network. In time scales spanning thousands of years, the alluvial fans along this Caribbean coastline are dynamic zones of high geomorphic activity. Because most of the coastal zone in Vargas consists of steep mountain fronts that rise abruptly from the Caribbean Sea, the alluvial fans provide practically the only flat areas upon which to build. Rebuilding and reoccupation of these areas requires careful determination of hazard zones to avoid future loss of life and property. KEY TERMS: Debris flows, flash floods, alluvial fans, natural hazards, landslides, Venezuela
Natural and induced endoreic hydrological conditions in the Alta Murgia karstic region (Apulia, Southern Italy)
NASA Astrophysics Data System (ADS)
Canora, F.; Fidelibus, M. D.; Spilotro, G.
A study aimed at understanding the hydrological processes in karst areas related to the presence of natural and artificial endoreic basins and their modification due to land use change, as well as the influence of above factors on the infiltration rate has been carried out in the Alta Murgia region (Apulia, Southern Italy). The region is a Cretaceous limestone plateau of the Apulian platform, characterized by a mature karstic landscape: due to its elevation, climatic conditions and lithology, the plateau constitutes the main recharge area of the Murgia aquifer. The typical karst topography is essentially related to the subterranean drainage (sinkholes, caves, conduit): surface and subsurface karst geomorphology is strictly interrelated with hydrology. The morphological features of the karstic plateau are defined by the high density of surface karstic forms (mainly dolines), the presence of exposed karst and karren fields, as well as by the extensive outcrop of fractured rocks. Karst surface shows, on the bottom of the morpho-structural depressions called "lame", natural distribution of modest deposits of "terra rossa" and regolith. The "lame" work as streams during and after intense rainfall events, often outlining a primordial ephemeral hydrographical network, frequently convergent towards dolines, poljes or endoreic basins. Alta Murgia shows many natural endoreic basin conditions in a quite flat morphology. In this environment, when intense rainfall events cover large areas and rainfall intensity exceeds the infiltration capacity of soils and/or sinkholes, significant runoff amounts are produced and stored in the basins causing floods. Most of the natural endoreic basins are small and independent: while the majority of them continue functioning as endoreic even in presence of extreme events of high return time, others (quasi-endoreic), under the same circumstances can start contributing to other basins, due to exceeding their water storage capability. This way
[Fishery and biometrics of genus Calappa crabs (Brachyura: Calappidae) in northeastern Venezuela].
Alió, José J; Marcano, Luis A; Altuve, Douglas E
The box crabs, genus Calappa, are important crab species landed by the industrial trawl fleet in Venezuela. These crabs have a wide distribution in the country, from the Gulf of Venezuela to the Orinoco River, but major landings take place in such gulf, near Margarita Island and northern Sucre State. Average annual landing in the eastern region was 69 t during 1970-2001, with a maximum of 221 t. For this study a sample of 2 398 box crabs was collected by observers on board of industrial trawl vessels, which operated in eastern Venezuela from 1994 to 2000. Three species were found in the landings, Calappa sulcata and C. flammea. each represented 47% of the sample, and C. nitida, which accounted for 5% of the sample. Sex ratio was strongly biased towards males in C. sulcata (2.8:1) and in C. flammnea (1.9:1). while it was only slightly biased in C. nitida (1.4:1). Due to its large size, C. sulcuta is of great commercial interest, with average weight 290 g and a maximum weight of 720 g: C. flammea showed an average weight of 140 g and a maximum weight of 418 g, while C. nitida is the smallest species, with average weight 46 g and maximum weight not beyond 113 g. Box crabs were captured by day and night in similar proportions, and were found in a wide depth range, from a few meters to 126 m deep; however, the largest captures were obtained in the interval 38 - 54 m. Regressions between weight of chelae and total weight were linear, and significantly different between sexes. The relation between total weight and carapace width was allometric, with a power exponent ca. three in C. sulcata, and less than three in C. flamea and C. nitida. Females of C. sulcata and C. nitida showed power exponents significantly smaller than males. Since claws are removed from the animal to be commercialized, while the rest of the animal is returned alive to the sea, for practical purposes a common equation among species and sexes to convert claws weight into total body weight is: total
Venezuela: from doctrine to dialogue to participation in the processes of regional development.
Allor, D J
The growing toward decentralization and democratization of development planning in Venezuela was discussed. Venezuela has a long tradition of rule by a strong centralized authority. Currently, the Office of the President is vested with considerable power, despite the existence of an elected legislator and an independent judiciary. The president rules by decree. State legislatures are elected, but governors of the states are appointed by the president. There are also elected municipal councils. Both state and municipal governments are almost fully dependent on the federal government for both their operating and capital investment budgets. Development programs are administered through 2 systems. Specific programs are administered by almost 100 different institutes and enterprises. The activities of these various programs are coordinated by administrative bodies at the state and federal level. The 2nd administrative system operates at the regional and federal levels. The administrative body at the federal level is the Central Office for Coordination and Planning and was established by Presidential Decree in 1958. This body prepares and coordinates all national development plans. The administrative bodies at the regional level are the Regional Organizations for Development. These bodies were created in specific regions through a series of legislative acts commencing in 1969 and continuing into the present. The development of these regional bodies represented a 1st step toward decentralization. Decree 478, promulgated in 1980, further promoted the decentalization of developmental planning. The decree established a series of assemblies and councils at various levels. A National Council of Regional Development was created at the federal level, and a Regional Council of Development was established at the regional level. At the state level an Assembly of Participation was organized, and at the municipal level a Committee of Citizen Participation was established
Geophysical studies for the identification of basin effects in urban areas in Venezuela
NASA Astrophysics Data System (ADS)
Schmitz, M.; Rocabado, V.; Sánchez, J.; Reinoza, C.; Amaris, E.; Cornou, C.
Urban areas in northern Venezuela are subject to a moderate seismic hazard due to the interactions between the Caribbean and south American plates, which has been evidenced by historical damaging earthquakes as for example the 1812 and the 1967 earthquakes with a magnitude of 7.2 and 6.5, respectively. Strong damages in Caracas during the 1967 earthquake have been asociated to site effects produced by the sediment filled basin. This situation can be observed in most of the big cities in northern Venezuela, which initially developped on plain areas with quaternary basin fills of up to 500 m within mountainous areas, as for example Caracas, Maracay and Barquisimeto. In the mid- 1990ies FUNVISIS started to promote geophysical studies to investigate the shape and the properties of the basin fills in order to contribute to the earthquake disaster reduction. Methods applied for the investigations are gravimetry, microtremor measurements, seismic refraction, among others. In Caracas, a total of 350 m of cuaternary sediments with an average S-wave velocity of about 850 m/s have been derived by seismic investigations. The corresponding predominant periods from microtremor measurements amount up to 2.2 s. Integrating drilling information and 3D gravimetric modeling a detailed picture of the bedrock - sediment interface could be obtained. Results from numerical modelling as well as from experimental transfer function indicate amplifications point to amplifications of a factor of more than 10 related to the deep basin area. In Barquisimeto Metropolitan Area, sediment thickness reaches up to 500 m in the fast growing Cabudare area. Actually, modelling of a recent seismic refraction campaign is in progress, but predominant periods up to 3.0 s in the deepest part of the valley and gravity modelling point to the same order of cuaternary sediments. In other cities, as for example Carora and Mérida, geophysical studies are in progress, first with gravimetric and microtremor
Seasonal prediction of lightning activity in North Western Venezuela: Large-scale versus local drivers
NASA Astrophysics Data System (ADS)
Muñoz, Á. G.; Díaz-Lobatón, J.; Chourio, X.; Stock, M. J.
The Lake Maracaibo Basin in North Western Venezuela has the highest annual lightning rate of any place in the world (~ 200 fl km- 2 yr- 1), whose electrical discharges occasionally impact human and animal lives (e.g., cattle) and frequently affect economic activities like oil and natural gas exploitation. Lightning activity is so common in this region that it has a proper name: Catatumbo Lightning (plural). Although short-term lightning forecasts are now common in different parts of the world, to the best of the authors' knowledge, seasonal prediction of lightning activity is still non-existent. This research discusses the relative role of both large-scale and local climate drivers as modulators of lightning activity in the region, and presents a formal predictability study at seasonal scale. Analysis of the Catatumbo Lightning Regional Mode, defined in terms of the second Empirical Orthogonal Function of monthly Lightning Imaging Sensor (LIS-TRMM) and Optical Transient Detector (OTD) satellite data for North Western South America, permits the identification of potential predictors at seasonal scale via a Canonical Correlation Analysis. Lightning activity in North Western Venezuela responds to well defined sea-surface temperature patterns (e.g., El Niño-Southern Oscillation, Atlantic Meridional Mode) and changes in the low-level meridional wind field that are associated with the Inter-Tropical Convergence Zone migrations, the Caribbean Low Level Jet and tropical cyclone activity, but it is also linked to local drivers like convection triggered by the topographic configuration and the effect of the Maracaibo Basin Nocturnal Low Level Jet. The analysis indicates that at seasonal scale the relative contribution of the large-scale drivers is more important than the local (basin-wide) ones, due to the synoptic control imposed by the former. Furthermore, meridional CAPE transport at 925 mb is identified as the best potential predictor for lightning activity in the Lake
Characterization of enzootic foci of Venezuelan equine encephalitis virus in western Venezuela.
Barrera, R; Torres, N; Freier, J E; Navarro, J C; García, C Z; Salas, R; Vasquez, C; Weaver, S C
The distribution of the sylvatic subtype ID Venezuelan equine encephalitis (VEE) viruses in the lowland tropical forests of western Venezuela was investigated using remote sensing and geographic information system technologies. Landsat 5 Thematic Mapper satellite imagery was used to study the reflectance patterns of VEE endemic foci and to identify other locations with similar reflectance patterns. Enzootic VEE virus variants isolated during this study are the closest genetic relatives of the epizootic viruses that emerged in western Venezuela during 1992-1993. VEE virus surveillance was conducted by exposing sentinel hamsters to mosquito bites and trapping wild vertebrates in seven forests identified and located by means of the satellite image. We isolated VEE viruses from 48 of a total of 1,363 sentinel hamsters in two of the forests on six occasions, in both dry and wet seasons. None of the 12 small vertebrates captured in 8,190 trap-nights showed signs of previous VEE virus infection. The satellite image was classified into 13 validated classes of land use/vegetation using unsupervised and supervised techniques. Data derived from the image consisted of the raw digital values of near- and mid-infrared bands 4, 5, and 7, derived Tasseled Cap indices of wetness, greenness, and brightness, and the Normalized Difference Vegetation Index. Digitized maps provided ancillary data of elevation and soil geomorphology. Image enhancement was applied using Principal Component Analysis. A digital layer of roads together with georeferenced images was used to locate the study sites. A cluster analysis using the above data revealed two main groups of dense forests separated by spectral properties, altitude, and soil geomorphology. Virus was isolated more frequently from the forest type identified on flat flood plains of main rivers rather than the forest type found on the rolling hills of the study area. The spatial analysis suggests that mosquitoes carrying the enzootic viruses
Purification and neuroprotective effects of polysaccharides from Opuntia Milpa Alta in cultured cortical neurons.
Chen, Yang; Zhao, Bo; Huang, Xiaolan; Zhan, Jinjin; Zhao, Yan; Zhou, Mei; Guo, Lianjun
Opuntia is a traditional plant from China with medicinal applications. In this experiment, polysaccharides from Opuntia Milpa Alta (MAPs) were analyzed using gas chromatograph-mass spectrometer (GC-MS) method and result showed that MAPs contained mannose (6.37%), rhamnose (14.94%), xylose (1.99%), arabinose (24.07%), galactose (38.25%), ribose (2.63%) and glucose (11.48%). The neuroprotective effects of MAPs were evaluated at the mechanistic level in vitro models of cerebral ischemic injury. In vitro oxygen/glucose deprivation (OGD) model, MAPs (0.5 μg/ml, 5 μg/ml, 50 μg/ml) effectively increased cell viability by methyl thiazolyl tetrazolium (MTT) assay, inhibited cell cytotoxicity by lactate dehydrogenase (LDH) assay, reduced neuronal cell death, suppressed the production of intracellular reactive oxygen species (ROS), decreased of intracellular free Ca(2+) concentrations ([Ca(2+)](i)), and reduced extracellular glutamate level. Therefore, MAPs might prevent intracellular calcium overload and decreased glutamate excitotoxicity, both of which can cause neuronal injury and death in vitro models of cerebral ischemic injury. PMID:21763720
Small mammals from the Chelemhá Cloud Forest Reserve, Alta Verapaz, Guatemala
Matson, Jason O.; Ordóñez-Garza, Nicté; Woodman, Neal; Bulmer, Walter; Eckerlin, Ralph P.; Hanson, J. Delton
We surveyed the small mammals of remnant mixed hardwood-coniferous cloud forest at elevations ranging from 2,100–2,300 m in the Chelemhá Cloud Forest Reserve, Alta Verapaz, Guatemala. Removal-trapping using a combination of live traps, snap traps, and pitfall traps for 6 days in January 2007 resulted in 175 captures of 15 species of marsupials, shrews, and rodents. This diversity of small mammals is the highest that we have recorded from a single locality of the 10 visited during eight field seasons in the highlands of Guatemala. Based on captures, the most abundant species in the community of small mammals is Peromyscus grandis (n = 50), followed by Handleyomys rhabdops (n = 27), Heteromys desmarestianus(n = 18), Reithrodontomys mexicanus (n = 17), Handleyomys saturatior (n = 16), Sorex veraepacis (n = 15), and Scotinomys teguina (n = 13). The remaining eight species were represented by one to five individuals.
Integrating complexity of social systems in natural hazards planning: An example from Caracas, Venezuela
NASA Astrophysics Data System (ADS)
Vranes, Kevin; Czuchlewski, Kristina R.
In December 1999, days of heavy rain on steep slopes north of Caracas, Venezuela triggered massive mud and debris flows, killing tens of thousands. Partly in response to this disaster, a multidisciplinary team of urban planners and Earth scientists from Columbia University recently developed a framework plan for building disaster resilience into the Venezuelan capital region. After assessing the complex intersection of urban geography with severe seismic and hydrologic hazards, substantial recommendations were made to local and regional authorities on future hazards mitigation.Areas found most at risk in the Caracas region include the transportation and utility infrastructure and the friable building stock of squatter settlements. Recognizing realistic economic and socio-political constraints on implementing change, a prioritized list of goals and activities was constructed, and recommendations made along various time scales. Immediate disaster-avoidance goals (to be completed within 1 to 5 years) include strengthening critical infrastructure nodes, housing stock, and emergency services. More intermediate goals (5 to 10 years) focus on upgrading fragile housing units, creating detailed hazard maps across the city, and incorporating disaster education into cultural activities. Recommended activities for the long term (beyond 10 years) include creating a fully redundant transportation and water delivery network, establishing legitimate land title for squatters, and re-locating critical facilities currently in high-risk areas.
Modeling Chagas Disease at Population Level to Explain Venezuela's Real Data
González-Parra, Gilberto; Chen-Charpentier, Benito M.; Bermúdez, Moises
Objectives In this paper we present an age-structured epidemiological model for Chagas disease. This model includes the interactions between human and vector populations that transmit Chagas disease. Methods The human population is divided into age groups since the proportion of infected individuals in this population changes with age as shown by real prevalence data. Moreover, the age-structured model allows more accurate information regarding the prevalence, which can help to design more specific control programs. We apply this proposed model to data from the country of Venezuela for two periods, 1961–1971, and 1961–1991 taking into account real demographic data for these periods. Results Numerical computer simulations are presented to show the suitability of the age-structured model to explain the real data regarding prevalence of Chagas disease in each of the age groups. In addition, a numerical simulation varying the death rate of the vector is done to illustrate prevention and control strategies against Chagas disease. Conclusion The proposed model can be used to determine the effect of control strategies in different age groups. PMID:26929912
Epidemiologic aspects of American visceral leishmaniasis in an endemic focus in Eastern Venezuela.
Zulueta, A M; Villarroel, E; Rodriguez, N; Feliciangeli, M D; Mazzarri, M; Reyes, O; Rodriguez, V; Centeno, M; Barrios, R M; Ulrich, M
An endemic focus of American visceral leishmaniasis (AVL) in eastern Venezuela has been evaluated in terms of patients (n = 48), immunologic reactivity to Leishmania in household contacts (n = 187) and neighborhood controls (n = 170), detection of Leishmania (L. donovani complex) in dogs and wild animals by the polymerase chain reaction (PCR) and characteristics of the sandfly population. The male:female ratio of patients was 1.18:1; 89.6% were < or =12 years old. Serologic reactivity was significantly higher in household contacts than in controls (P = 0.0008), as was the size of leishmanin reactions in contacts < or =10 years of age (P = 0.0141). Leishmania donovani complex-specific PCRs were positive in dogs, an opossum (Didelphis marsupialis), and a black rat (Rattus rattus). Lutzomyia longipalpis and Lu. evansi, both implicated in the transmission of AVL, were identified among the 386 sand flies examined. These observations provide the bases for an active control program as well as further studies of reservoirs and vector-host relationships in this area. PMID:10674675
Ecological studies of enzootic Venezuelan equine encephalitis in north-central Venezuela, 1997-1998.
Salas, R A; Garcia, C Z; Liria, J; Barrera, R; Navarro, J C; Medina, G; Vasquez, C; Fernandez, Z; Weaver, S C
From 1997-1998, we investigated the possible continuous circulation of epizootic Venezuelan equine encephalitis (VEE) virus suggested by a 1983 subtype IC interepizootic mosquito isolate made in Panaquire, Miranda State, Venezuela. The study area was originally covered by lowland tropical rainforest but has been converted into cacao plantations. Sentinel hamsters, small mammal trapping, mosquito collections, and human serosurveys were used to detect active or recent virus circulation. Six strains of subtype ID VEE virus were isolated from hamsters that displayed no apparent disease. Four other arboviruses belonging to group A (Togaviridae: Alphavirus), two Bunyamwera group (Bunyaviridae), and three Gamboa group (Bunyaviridae) arboviruses were also isolated from hamsters, as well as 8 unidentified viruses. Venezuelan equine encephalitis-specific antibodies were detected in 5 small mammal species: Proechimys guairae, Marmosa spp., and Didelphis marsupialis. Mosquito collections comprised of 38 different species, including 8 members of the subgenus Culex (Melanoconion), did not yield any virus isolates. Sera from 195 humans, either workers in the cacao plantation or nearby residents, were all negative for VEE virus antibodies. Sequences of 1,677 nucleotides from the P62 gene of 2 virus isolates indicated that they represent a subtype ID lineage that is distinct from all others characterized previously, and are unrelated to epizootic VEE emergence. PMID:11425168
Solar and Volcanic Modulation of Little Ice Age Climate in the Tropical Andes, Venezuela
NASA Astrophysics Data System (ADS)
Polissar, P. J.; Abbott, M. B.; Wolfe, A. P.; Rull, V.; Bezada, M.
The underlying causes of late-Holocene climate variability in the tropics are incompletely understood. Here, we report a 1500-year reconstruction of climate history in the Venezuelan Andes using lake sediment records from four sites. This reconstruction is based upon accelerator mass spectrometry (AMS) radiocarbon and Pb-210 dating, sedimentology, magnetic susceptibility, geochemistry, pollen and stable isotope (C, N) measurements. In the Laguna Mucubaji watershed four distinct glacial advances occurred between 1250 and 1810 A.D. The earliest advance began during an extended period of higher global volcanic activity. The subsequent three advances were coincident with minima in solar activity (reconstructed from Be-10 and C-14 records). The Mucubají glacial activity in the Venezuelan Andes coincides with other records of Little Ice Age (LIA) glacial advances in S. America. Comparison of modern glacier equilibrium line altitudes (ELAs) in Venezuela with the Mucubaji LIA glacier ELA indicates an ELA depression of at least 300 m. Both a decline in temperature and increase in precipitation are required to explain the ELA depression. The precipitation increase is supported by increased catchment erosion recorded in L. Blanca sediments. Pollen records from two sites in the Venezuelan Andes also indicate wetter and colder conditions during the LIA.
Enhanced Seasonal Rainfall in Northern Venezuela and the Extreme Events of December 1999.
NASA Astrophysics Data System (ADS)
Lyon, Bradfield
Torrential rainfall during December 1999 resulted in devastating floods and landslides along the northern coast of Venezuela. These events occurred in an area with a predominantly dry climate, took place during what is regionally the dry season, and were preceded by unusually heavy seasonal rainfall. An observational study was undertaken in an attempt to identify anomalous features of the climate system associated with both the enhanced seasonal rainfall prior to the landslides as well as the extreme December rainfall events that triggered them. Observational data for the period 1950-99 are used to provide historical context. Results indicate that the copious seasonal rainfall prior to the floods was associated with anomalous conditions in both the tropical Pacific and Atlantic basins similar to past events, although some features were unusually strong in 1999. The extreme daily rainfall in December 1999 was associated with atmospheric circulation features originating in the extratropical Northern Hemisphere that penetrated unusually far into the Tropics. Possible physical mechanisms acting to enhance rainfall on both timescales are discussed.
Oceanic influence on the precipitation in Venezuela under current and future climate
NASA Astrophysics Data System (ADS)
Tim, Nele; Bravo de Guenni, Lelys
The Pacific and Atlantic oceanic influences on observational rainfall data from weather stations over Venezuela are analyzed using Canonical Correlation Analysis (CCA) executed in the Climate Predictability Tool. CCA is further conducted on rainfall and sea surface temperature data obtained from the Max Planck Institute for Meteorology Earth System Model (MPI-ESM) for historical (1951-2010) and future (2041-2100) periods. Four oceanic regions (North Tropical Atlantic, Niño3, Niño3.4 and an area which includes all previous three) are used for the CCA using data from the Extended Reconstructed Sea Surface Temperature (ERSST) data set, while precipitation data from two regions: a coastal region and an inland region are used in the analysis. Venezuelan seasons (dry and wet) were separated into an early and a late period. The oceanic impact on the precipitation of the station data is, in the majority of the cases, higher in the inland than at the coast. The Pacific's influence is stronger in the early dry season than in the wet season, whereas the Atlantic's influence is stronger in the wet season (inland). In contrast, CCA applied to the model data provides highest correlation coefficients in the late wet season for all oceanic regions. In most cases the North Tropical Atlantic has a stronger influence than the Niño regions.
[Diarrheagenic Escherichia coli associated with acute diarrhea in children of Cumaná, Venezuela].
Hannaoui, Erika; Villalobos, Luz; Martínez, Rosa; Maldonado, Antonio; Hagel, Isabel; Bastardo, Jesús
To establish the prevalence of strains of diarrheagenic Escherichia coli (DEC) associated to acute diarrhea in children of Cumaná, Venezuela, stool samples were taken from 200 children aged < 5 years with acute diarrheal disease, and from 30 healthy children used as control. Isolation and bacterial identification was performed by conventional biochemical tests and stool cultures. The presence of pathogenic genes of each type of DEC was investigated by the technique of polymerase chain reaction (PCR), determining the genes eae and bfp (EPEC), st and lt (ETEC), ipaH and virF (EIEC) Stx1/Stx2 (STEC), aafII (EAEC) and daaE (ADEC). From 169 E. coli, isolates we determined by PCR 10.65% positive for EPEC (1.18% "typical", 9.47% "atypical"); ETEC (5.91%); EAEC (1.78 %), EIEC (0.59%). There were no statistically significant differences regarding the frequency of each "pathotype" in relation to age, but it did occur when related to the sex (p<0.05). The most relevant clinical features were: fever, vomiting and abdominal pain and the greatest percentage of children affected were of the working and marginal classes. These results shown that the strains of DEC are important etiological agents in acute infectious diarrhea in children of Cumaná. PMID:21365876
Comparative study of the chemical composition of essential oils of five Tagetes species collected in Venezuela.
Armas, Kaylin; Rojas, Janne; Rojas, Luis; Morales, Antonio
The leaves and inflorescences of five species of Tagetes, family Asteraceae, were collected from different locations in Mérida state, Venezuela, and their essential oils analyzed by GC and GC/MS. Several differences were observed in the composition of these oils, mainly regarding the major components, which for T. caracasana were trans-ocimenone (64.3%) and cis-tagetone (13.7%), and for T. erecta, piperitone (35.9%) and terpinolene (22.2%). High amounts of trans-anethole (87.5%) and estragole (10.7%) were observed in T. filifolia, while T. subulata essential oil contained terpinolene (26.0%), piperitenone (13.1%) and limonene (10.8%). For T. patula, two different oil samples were analyzed, leaves (TPL) and inflorescences (TPI). The TPL oil showed terpinolene (20.9%) and piperitenone (14.0%) as main components, while the TPI sample was composed mainly of beta-caryophyllene (23.7%), terpinolene (15.6%) and cis-beta-ocimene (15.5%). PMID:23074915
[Spatio-temporal variation of subtidal meiofauna in a sandy beach from Northeastern Venezuela].
Arana, Ildefonso Liñero; Ojeda, Sol; Amaro, María Elena
Meiofauna organisms that play an important role in the trophic ecology of soft bottom benthos, have short life cycles and they respond quickly to disturbance and pollution. The present study shows the spatio-temporal variation ofsubtidal meiofauna (metazoans passing a 500im sieve but retained on meshes of 40-63micro m) in four shallow subtidal stations. Samples were taken in the sandy beach of San Luis, in the Northeastern coast of Venezuela, from October 2005 until September 2006. For this, three replicate sediment core samples (4.91cm2), were collected monthly to a depth of 10cm into the sediment, and preserved in 6% formalin stained with rose Bengal. Specimens of 14 meiofaunal groups (Foraminifera excluded) were collected, being the nematodes, ostracods and harpacticoid copepods the most abundant. Monthly density was comprised between 64 and 503ind./10cm2, and mean density of stations between 173 and 449ind./10cm2. There is a trend of low densities from October to February (end of the rainy season until the middle of the dry season). The San Luis beach control of the meiofaunal community is shared by climatic conditions and by the biology of the species found. The meiofauna mean density in San Luis beach (263ind./10cm2) was low when compared to other studies in tropical areas. PMID:23894963
The hydrocarbon habitat of northern South America: Colombia-Venezuela-Trinidad
James, K.H.
A prolific hydrocarbon province extends across the northern margin of South America from Colombia to east of Trinidad. Two key components are a world-class source rock, formed on a regional Late Cretaceous passive margin, and a complex tectonic setting in which a variety of structural and stratigraphic traps, reservoirs, seals and hydrocarbon kitchens have evolved through time. Convergence between the Farallon and Caribbean plates with South America culminated in the late Cretaceous-early Palaeogene with emplacement of Colombia`s Central Cordillera in the west and a nappe-foreland basin system in the north. Regional hydrocarbon generation probably occurred below associated basins. Subsequent oblique convergence between the Caribbean and South America, partitioned into strike-slip and compressional strain, generated an eastward migrating and ongoing uplift-foredeep (kitchen) system from central Venezuela to Trinidad. Similarly, oblique interaction of western Colombia with the Nazca Plate caused segmentation of the earlier orogen, northward extrusion of elements such as the Maracaibo Block, and eastward migration of uplift progressively dividing earlier kitchens into localized foredeeps.
Influence of Mesozoic age structure on Miocene tectonic development in NE Anzoategui, Eastern Venezuela Basin
Sadler, P.; White, S.
Structure within and surrounding the Quiamare-La Ceiba region, Eastern Venezuela Basin, is dominated by two major thrust fault systems. They were generated during Early-Middle Miocene time in response to oblique convergence of the Caribbean and South American plates. They are. respectively, the SE vergent NE-SW oriented Anaco fault system, and the SSE vergent ENE-WSW oriented Pirital fault system. The major structural feature associated with each fault system is a basement cored ramp anticline. New seismic data provides evidence that contributes to a better understanding of the sequence of tectonic development within and surrounding the Quiamare-La Ceiba region. Compressional structures in both the hanging wall and the footwall of the Pirital fault system appear to be inverted normal faults, that were previously active during Mesozoic time along the northern South America passive margin. A conjugate set of strike-slip faults is also present. They are oriented NNW-SSE, parallel to the Urica lineation, and SSW-NNE, respectively. A Mesozoic origin for these faults is suggested. Post-compressional relaxation during Plio-Pleistocene time resulted in the development of shallow, small scale normal faults. These normal faults appear to be localized by structural adjustments along the strike-slip fault sets. Existing oil and gas production within the Quiamare-La Ceiba region is from localized structural closures. Strike-slip faults dissect the prevailing structural grain, and may provide an additional hydrocarbon trapping mechanism.
Mycobiota and concentration of ochratoxin A in concentrated poultry feed from Venezuela.
Figueroa, S; Centeno, S; Calvo, M A; Rengel, A; Adelantado, C
The main objective of this study was to evaluate the frequency distribution of mycobiota and the concentration of Ochratoxin A (OTA) in 50 samples from one company of commercial brand poultry feed produced in Venezuela. The concentration of OTA in the samples analyzed was determined using the competitive ELISA method. The most frequently isolated genera of moulds were Aspergillus (36%) and Penicillium (20%). Of these genera, the most frequently isolated species were Aspergillus flavus, Aspergillus terreus and Penicillium citrinum. Ochratoxigenic species such as Eurotium herbariorum, Aspergillus niger, Aspergillus ochraceus and Aspergillus glaucus, were also found with lower frequency. Rhodotorula mucilaginosa was the only yeast isolated. 94% of the samples presented contamination by OTA in a range between 2.558 and 31.978 microg kg(-1) feed and 42% of them presented OTA levels from 10 up to 20 microg kg(-1). The findings of this investigation show that 84% of the samples of concentrated feed for meat poultry surpass the maximum permitted limit for OTA of 5 microg kg(-1), established in the majority of countries in which regulations are placed. PMID:19580016
Cutaneous leishmaniasis in western Venezuela caused by infection with Leishmania venezuelensis and L. braziliensis variants.
Bonfante-Garrido, R; Meléndez, E; Barroeta, S; de Alejos, M A; Momen, H; Cupolillo, E; McMahon-Pratt, D; Grimaldi, G
Between 1975 and 1987, epidemiological studies were carried out in several rural and urban communities in the central part of western Venezuela, especially in the state of Lara. 115 positive cultures were obtained from human cases and identified by their reactivity patterns to a cross-panel of specific monoclonal antibodies using a radioimmune binding assay; 53 were Leishmania venezuelensis and 62 were L. braziliensis. Most of these stocks were also characterized by isoenzyme electrophoresis, which confirmed the identification of the L. venezuelensis isolates. The enzyme electrophoretic profiles of the L. braziliensis isolates, however, revealed two populations with distinct electromorphs, one related to the World Health Organization L. braziliensis reference strain while the other population appeared to be a hybrid between L. braziliensis and L. guyanensis. L. braziliensis variants showed the widest geographical distribution, and were found in 7 states: Districto Federal (Caracas); Lara (Barquisimeto, Crespo, Iribarren, Jimenez, Morán, Palavecino, Torres, Urdaneta); Nueva Esparta (Margarita); Portuguesa (Las Cruces, Rio Amarillo); Trujillo (Cuicas); Yaracuy (Agua Fria, Cambural, Guaremal); and Zulia (Zipa-Yare). L. venezuelensis was found in the following endemic regions: Lara (Barquisimeto, Iribarren, Jimenez, Morán); Merida (Zéa); and Yaracuy (Campos Elias), showing that this parasite has a much wider geographical distribution than was initially recognized and that both these species can occur simultaneously within the same endemic region. Five isolates of L. braziliensis were made from infected donkeys (Equus asinus) in Urdaneta, Lara State, suggesting a possible domestic reservoir of L. braziliensis. PMID:1440772
Political economy of petrodollars: oil and democracy in Venezuela (Volumes I and II)
Karl, T.L.
This thesis explores the impact of changes in the international petroleum economy upon the development strategy and political process of one oil-producing nation, Venezuela. It contends that sudden great wealth, like scarcity, can be a serious development curse, leading to policy decisions that provoke economic disruption and political decay. This ''paradox of plenty'' can best be explained by the interplay of an internationally-generated crisis of wealth with the skewed socio-economic arrangements and weak states characteristic of late developers. This interaction results in management overload and a subsequent decline in the problem-solving abilities of the state, making the effective utilization of petrodollar surpluses exceedingly difficult. An investigation of the political and economic consequences of the Perez Adminsitration's attempt to build a diversified industrial structure following the quadrupling of oil prices in 1973 illustrates this central theme. President Perez' ''project'' of accelerated modernization, designed to meet the competing demands of party and business interests, led to a contradictory development model which was both populist and entrepreneurial.
Tectonic implications of Paleocene-Eocene Foreland Basin, Lake Maracaibo, Venezuela
Lugo, J. ); Mann, P. )
A compilation of industry geological and geophysical data indicates that Paleocene-Eocene clastic sedimentation in the Maracaibo basin records the first manifestation of Cenozoic foreland basin tectonics in northern South America. Isopach maps based on industry seismic data and well logs suggest that the Maracaibo foreland basin formed a 100 to 200 km wide elongate trough along the northeastern edge of the present-day Lake Maracaibo. The basin is asymmetric with a deep (7 km) northeastern margin adjacent to an exposed southwest-verging thrust belt mapped by previous workers. Isopach mapping of seven seismic units within the Eocene suggest a nor-northwest to southeast migration of the depocenter from Paleocene to Middle Eocene time at a rate of 0.6 cm/year. A similar style of foreland basin has been previously identified over a distance of 1000 Km from western central Venezuela to Trinidad. Eocene to Pliocene ages of foreland basin sedimentation in these areas suggest time transgressive, oblique collision of the Caribbean plate along the northern margin of South America. Comparison of the age of deformation along both the northern and southern edges of the pro-Caribbean plate yield reasonable estimates for the rate of relative motion of this small plate relative to the larger America plates.
Monitoring coastal pollution associated with the largest oil refinery complex of Venezuela
Bone, David; Bastidas, Carolina; Ramos, Ruth
This study evaluated pollution levels in water and sediments of Península de Paraguaná and related these levels with benthic macrofauna along a coastal area where the largest Venezuelan oil refineries have operated over the past 60 years. For this, the concentration of heavy metals, of hydrocarbon compounds and the community structure of the macrobenthos were examined at 20 sites distributed along 40 km of coastline for six consecutive years, which included windy and calm seasons. The spatial variability of organic and inorganic compounds showed considerably high coastal pollution along the study area, across both years and seasons. The southern sites, closest to the refineries, had consistently higher concentrations of heavy metals and organic compounds in water and sediments when compared to those in the north. The benthic community was dominated by polychaetes at all sites, seasons and years, and their abundance and distribution were significantly correlated with physical and chemical characteristics of the sediments. Sites close to the oil refineries were consistently dominated by families known to tolerate xenobiotics, such as Capitellidae and Spionidae. The results from this study highlight the importance of continuing long-term environmental monitoring programs to assess the impact of effluent discharge and spill events from the oil refineries that operate in the western coast of Paraguaná, Venezuela. PMID:27375970
Malaria entomological risk factors in relation to land cover in the Lower Caura River Basin, Venezuela
Rubio-Palis, Yasmin; Bevilacqua, Mariapia; Medina, Domingo Alberto; Moreno, Jorge Ernesto; Cárdenas, Lya; Sánchez, Víctor; Estrada, Yarys; Anaya, William; Martínez, Ángela
To explore the effects of deforestation and resulting differences in vegetation and land cover on entomological parameters, such as anopheline species composition, abundance, biting rate, parity and entomological inoculation rate (EIR), three villages were selected in the Lower Caura River Basin, state of Bolívar, Venezuela. All-night mosquito collections were conducted between March 2008-January 2009 using CDC light traps and Mosquito Magnet(r) Liberty Plus. Human landing catches were performed between 06:00 pm-10:00 pm, when anophelines were most active. Four types of vegetation were identified. The Annual Parasite Index was not correlated with the type of vegetation. The least abundantly forested village had the highest anopheline abundance, biting rate and species diversity. Anopheles darlingi and Anopheles nuneztovari were the most abundant species and were collected in all three villages. Both species showed unique biting cycles. The more abundantly forested village of El Palmar reported the highest EIR. The results confirmed previous observations that the impacts of deforestation and resulting changes in vegetation cover on malaria transmission are complex and vary locally. PMID:23579803
Seismic hazard analysis of Western Venezuela methodology and data collection process
Savy, J.
The purpose of this project, initiated by INTEVEP is to develop a seismic hazard characterization for the region of the Lake Maracaibo basin in Western Venezuela (WV) with an emphasis at the sites of dikes built on the eastern side of the lake. One task of the project was to assess the seismicity of this region and to describe it in a form which can be used as input to a seismic hazard analysis. The seismic parameters of interests were seismo-tectonic zonation, distribution of earthquake magnitudes, and the largest earthquake, i.e., upper magnitude cutoff. Because it is difficult, or perhaps impossible, to precisely quantify such seismic parameters using only the sparse historical record, expert judgment is crucial. Thus two panels of experts were assembled, to supplement the lack of opinions in the possible models of zonation, seismicity, (S-panel) and ground motion attenuation (G-panel). In addition to the ground motion models described in the ground motion questionnaire handed to the G-panel experts, we performed some analysis, at LLNL, to develop a new breed of models where the parameter of interest is now the number of cycles of a given fraction of the peak ground acceleration, as a function of magnitude and distance from the source of an earthquake, rather than the peak ground acceleration (PGA) as a function of magnitude and distance. 20 refs.
Geological photointerpretation of the Paraguana Peninsula using ERTS-A multispectral photography. [Venezuela
NASA Technical Reports Server (NTRS)
Albrizzio, C.
A methodology was developed to evaluate multispectral analysis of orbital imagery on the interpretation of geology, coastal geomorphology and sedimentary processes. The images analyzed were obtained during the pass of ERTS satellite over the center region of Venezuela on October 19, 1972. ERTS-1 multispectral images in black and white paper copies and transparencies of the 4 bands and false color composites at scales of 1:1,000,000 and 1:500,000 were interpreted. Lithology and outcrop patterns of the following geological formations have been interpreted: igneous and metamorphic basement of Cocodite and Santa Ana, Jurassic-Cretaceous metamorphics of Pueblo Nuevo, Cantaure Miocene-Pliocene sediments, and Quaternary alluvium, dunes, beach ridges, bars and reefs. A prominent and extensive Paraguana tonal anomaly shaped as an 8 has been discovered at the NW of the Peninsula. Its erosional origin has exposed light toned lower beds at the center, with additional evidence of topographic depression and development of underground drainage of karst origin. Coastal geomorphology, its processes and energy has been interpreted with the help of wind direction analysis (ENE-WSW) at sea level through the orientation of transported materials (water vapor, water and sediments) by clouds, waves, sea current, plumes of suspended sediments associated to river outlets, dunes, sediment sources and shore-line orientation.
Diagenesis and reservoir characterization of the Cretaceous-Tertiary sequence, eastern Venezuela
Aquado, B.; Ghosh, S.; Isea, A. )
The giant El Furrial field Maturin subbasin is the most important oil field discovered in Venezuela in the last three decades. The average oil column has a thickness of 400 m and the reservoirs consist of essentially sandy siliciclastic sediments of nearshore-shallow marine origin. The oil's API gravity ranges from light to extra heavy and occurs in a stratified manner in the reservoirs. A total of 1,080 m of core from the producing sequence was studied through x-ray diffraction scanning electron microscopy, and petrography. This data, along with petrophysical measurements, show a clear differentiation between the Upper Cretaceous and the Oligocene reservoirs. The Upper Cretaceous reservoirs are characterized by relatively fine and uniform grain size, subarkosic composition with common volcanic rock fragments, high degree of chemical and mechanical compaction highly illitic mixed-layer I/S assemblage with less than 10% expandable layers, and ubiquitous baroque dolomite. Additionally, porosity and permeability values are persistently low. Clearly, the Cretaceous sediments are diagenetically mature and may indicate diagenetic transformation at greater depths or under a different thermal regime. In contrast the coarser grained Oligocene reservoirs of quartz arenitic composition show a lesser diagenetic overprint, and greater porosity and permeability. Porosity is dominantly secondary due to cement and grain (mostly quartz) dissolution, as well as tectonically induced grain fracturing. Common kaolinite and minor amounts of I/S with up to 20% of expandable layers attest to a lower diagenetic regime than in the Cretaceous reservoirs.
Chemical kinetic model of hydrocarbon generation, expulsion, and destruction applied to the Maracaibo basin, Venezuela
Sweeney, J.J.; Braun, R.L.; Burnham, A.K.
This paper describes the development and application of a compositional chemical model of hydrocarbon generation, expulsion,a nd destruction for the Cretaceous La Luna Formation source rock of the Maraciabo basin, Venezuela. Applications include both laboratory and geological settings. Laboratory pyrolysis experiments were used to study bulk oil generation, expulsion, and associated changes in composition of the kerogen, extractable organic matter, and expelled and unexpelled hydrocarbons. The laboratory experiments were also used to determine kinetic parameters to quantitatively describe organic reactions, via a computer model that also includes simulation of pressure-driven primary expulsion, over widely varying conditions. We show that the chemical model accuratley simulates the experimental results. Thermal history models for wells in the Maraciabo basin were used to simulate hydrocarbon generation and pore pressure development in the La Luna Formation and expulsion into nearby Cretaceous reservoirs. Results of the modeling indicate that both compaction disequilibrium and organic maturation play important roles in the development of excess pore pressure in the La Luna Formation. The model simulation of the variation of indicators such as Rock-Eval parameters and extract and oil compositions shows generally good agreement with measurements from remaining kerogen, oils, and extracts recovered from the La Luna Formation and from nearby Cretaceous reservoirs.
A new rabbit species (Sylvilagus, Mammalia: Leporidae) from the lowlands of Venezuela.
Durant, P; Guevara, M A
A new species of Venezuelan rabbit of the genus Sylvilagus from Fundo Millano (08 degrees 46'N and 69 degrees 56'W) and Chorrosco Bajo (08 degrees 05'N and 69 degrees 18'W), between 190 and 120 masl, state of Barinas, is described based on: 1. Body and skull measurements. 2. Coloration patterns of the pelage. 3. Arrangement and length of the color hair bands of dorsal, lateral, ventral nuchal, and gular patches. Body and cranial measurements, and some color patterns of the new species, Sylvilagus varynaensis, were compared with those of the closest relative groups such as S. brasiliensis (from Venezuela and Brazil), S. b. meridensis from the Venezuelan paramos, and three of the most representative groups of S. floridanus (S. f. continentis, S. f. orinoci, and S. f. valenciae). Most of the values recorded for these parameters were significantly higher for the new species (P < 0.005; Student "t" test). Cluster and principal components analysis of the data recorded for cranial characteristics indicated that S. varynaensis is the largest and darkest of the known Venezuelan rabbits, with a broader elongated skull and a different arrangement of the color hair bands. PMID:11795167
Arbuscular mycorrhizas in coastal sand dunes of the Paraguaná Peninsula, Venezuela.
Alarcón, C; Cuenca, G
Arbuscular mycorrhizal colonization was measured in the most abundant plant species of the Paraguaná Peninsula, northwestern Venezuela. These plant species included: Acacia tortuosa, Argusia gnaphalodes, Croton punctatus, Croton rhamnifolius, Egletes prostrata, Melochia tomentosa, Panicum vaginatum, Scaevola plumieri, Sporobolus virginicus, Suriana maritima, Leptothrium rigidum, and Fimbristylis cymosa. Mycorrhizal colonization was assessed using the Trouvelot et al. (1986) method that allows for simultaneous evaluation of frequency of colonization (%F), intensity of colonization (%M), and the proportion of arbuscules (%A) and vesicles (%V) present in the roots. Average frequency of colonization was 69%. The highest frequency of colonization was around 92% in C. rhamnifolius and A. tortuosa; in the other species, it varied from 49 to 86%. L. rigidum and F. cymosa were considered nonmycorrhizal because its colonization was very scarce and at all times appeared without arbuscules. Average intensity of colonization was 7%. The highest intensity of colonization was 18% in C. rhamnifolius. In the other species, it varied from 3 to 15%. Paspalum vaginatum, A. gnaphalodes, M. tomentosa, and S. maritima had their fungal structures tightly packed in modified little ovoid roots. In general, frequency of AM colonization was high and similar to those reported for other tropical ecosystems, whereas the intensity of AM colonization was low and similar to values obtained in analogous studies in disturbed ecosystems. PMID:16007471
[Diversity, abundance and distribution of benthic macrofauna on rocky shores from North Sucre State, Venezuela].
Fernandez, Johanna; Jiménez, Mayré; Allen, Thays
The rocky intertidal zone is among the most extreme physical environments on Earth. Organisms living in this area are constantly stricken by physico-chemical and biological factors. Due to the ecological importance of these areas, we studied the diversity, abundance and distribution of the rocky coastline benthic macrofauna, from the North coast of Sucre State, Venezuela. We performed bimonthly samplings from November 2008 to September 2009. The collection of biological material in the littoral zone (supra, mid and infralittoral) was done manually with a grid of 0.25m2. Organisms were preserved in 10% formalin for later identification and analysis (ecological parameters and Kruskal-Wallis test to the abundance and diversity). We found a total 19,020 organisms (86 spp.), in 8 phyla, 45 families and 47 genera. Mollusks were the most abundant and diverse (58 spp.), followed by arthropods (12 spp.), annelids (7 spp.), echinoderms (5 spp.), and the less represented cnidarians, sipunculids, nemertinids and urochordates (1 sp.). The zonation found coincided with the universal scheme of zonation. The towns of Rio Boca and Rio Caribe presented the highest values of ecological parameters, and the lowest were found in Playa Grande. Statistical significant differences were found in the abundance and diversity of macrofauna among the three zones. The little information on the composition and distribution of macrobenthic rocky coastline, prevents a better comparison, however the results contribute to the knowledge of the marine biodiversity in this region. PMID:25412527
Epidemiologic characterization of American cutaneous leishmaniasis in an endemic region of eastern Venezuela.
Jorquera, A; Ledezma, E; De Sousa, L; Garcia, A; Sanchez, J; Zerpa, J; Gonzalez, R; O'Daly, J A
The status of American cutaneous leishmaniasis was investigated from 1985 to 1991 to provide an epidemiologic characterization of the disease in Bergantin, a rural community in the northeastern part of Anzoátegui State, Venezuela. The study revealed the presence of the infection during the period analyzed, with an average incidence of 50.2 cases per 10,000 inhabitants and this number has increased 1.5 times during the last two years. Three villages where clinical cases had been recorded were selected for a comparison of their prevalence data. These villages comprise the human population in the high and low altitude limits of Bergantin. Immunologic assessment of the inhabitants used two different antigen preparations to examine responses to parasites associated with the cutaneous and visceral forms of the disease. The leishmanin skin test (LST) was used in a sample of 276 individuals (46.3% of the inhabitants) and resulted in an overall positivity of 16.7%. The percentage of LST positivity varied with age and sex, yet analysis of this response and the prevalence for each village reflected the specific characteristics of these localities. La Montaña, situated at 800 meters above sea level, had the highest prevalence (800 cases per 10,000 inhabitants) and the most positive LST response (21.2%) in comparison with the two other villages situated at a lower altitude (300 meters above sea level). PMID:9598446
Patterns of ant (Hymenoptera: Formicidae) richness and relative abundance along an aridity gradient in Western Venezuela.
Pérez-Sánchez, A J; Lattke, J E; Viloria, A L
In xeric ecosystems, ant diversity response to aridity varies with rainfall magnitude and gradient extension. At a local scale and with low precipitation regimes, increased aridity leads to a reduction of species richness and an increased relative abundance for some ant species. In order to test this pattern in tropical environments, ant richness and relative abundance variation were evaluated along 35 km of an aridity gradient in the Araya Peninsula, state of Sucre, Venezuela. Three sampling stations comprising five transects each were set up. Pitfall traps and direct collecting from vegetation were assessed per transect. Overall, 52 species, 23 genera, and 7 subfamilies of ants were recorded in the peninsula. The total number of species and genera recorded by both sampling stations and transects decreased linearly with increasing aridity. Total relative abundance was highest in the most arid portion of the peninsula, with Crematogaster rochai (Forel) and Camponotus conspicuus zonatus (Emery) (Hymenoptera: Formicidae) being the numerically dominant species. Spatial and multivariate analyses revealed significant changes in ant composition every 11 km of distance, and showed a decrease of ant diversity with the increase of harsh conditions in the gradient. Here, we discuss how local geographic and topographic features of Araya originate the aridity gradient and so affect the microhabitat conditions for the ant fauna. PMID:23949745
Estimation of the intrinsic absorption and scattering attenuation in Northeastern Venezuela (Southeastern Caribbean) using coda waves
Ugalde, A.; Pujades, L.G.; Canas, J.A.; Villasenor, A.
Northeastern Venezuela has been studied in terms of coda wave attenuation using seismograms from local earthquakes recorded by a temporary short-period seismic network. The studied area has been separated into two subregions in order to investigate lateral variations in the attenuation parameters. Coda-Q-1 (Q(c)-1) has been obtained using the single-scattering theory. The contribution of the intrinsic absorption (Q(i)-1) and scattering (Q(s)-1) to total attenuation (Q(t)-1) has been estimated by means of a multiple lapse time window method, based on the hypothesis of multiple isotropic scattering with uniform distribution of scatterers. Results show significant spatial variations of attenuation: the estimates for intermediate depth events and for shallow events present major differences. This fact may be related to different tectonic characteristics that may be due to the presence of the Lesser Antilles subduction zone, because the intermediate depth seismic zone may be coincident with the southern continuation of the subducting slab under the arc.
Biostratigraphic sequence analysis of Oligocene-Lower Miocene sections in the Orocual Field, Eastern Venezuela Basin
Giffuni, G.; Castro-Mora, M.
A detailed biostratigraphic study of the Oligocene-Miocene boundary was carried out in sections 1000 ft thick of ten wells of the Orocual Field, Eastern Venezuela, The sequences under investigation carry a rich microfauna of benthic and planktonic foraminifera and calcareous nannoplankton. About 500 samples were analyzed and nearly 150 species of foraminifera and 60 of nannoplankton calcareous were identified. The planktonic assemblages allow the identification of zones N3 and N4 of Blow, 1969; zones NP23, NP24, NP25 and NN1 of Martini, 1971; and zones F and E of Stainforth et al., 1959 of the Carapita Formation. The paleoenvironments of these sediments were determined rather precisely and vary from inner shelf to middle slope. Paleobathymetric curves of several wells are included. High and low fossil abundance and diversity peaks were used to recognize two sequences of the third order and five of the fourth order between 24.8 Ma and 26.5 Ma. A generalized transgressive trend is evident from the Late Oligocene to the Early Miocene.
Oceanic influence on the precipitation in Venezuela under current and future climate
NASA Astrophysics Data System (ADS)
Tim, Nele; Bravo de Guenni, Lelys
The Pacific and Atlantic oceanic influences on observational rainfall data from weather stations over Venezuela are analyzed using Canonical Correlation Analysis (CCA) executed in the Climate Predictability Tool. CCA is further conducted on rainfall and sea surface temperature data obtained from the Max Planck Institute for Meteorology Earth System Model (MPI-ESM) for historical (1951-2010) and future (2041-2100) periods. Four oceanic regions (North Tropical Atlantic, Niño3, Niño3.4 and an area which includes all previous three) are used for the CCA using data from the Extended Reconstructed Sea Surface Temperature (ERSST) data set, while precipitation data from two regions: a coastal region and an inland region are used in the analysis. Venezuelan seasons (dry and wet) were separated into an early and a late period. The oceanic impact on the precipitation of the station data is, in the majority of the cases, higher in the inland than at the coast. The Pacific's influence is stronger in the early dry season than in the wet season, whereas the Atlantic's influence is stronger in the wet season (inland). In contrast, CCA applied to the model data provides highest correlation coefficients in the late wet season for all oceanic regions. In most cases the North Tropical Atlantic has a stronger influence than the Niño regions.
Estimation of undiscovered deposits in quantitative mineral resource assessments-examples from Venezuela and Puerto Rico
Cox, D.P.
Quantitative mineral resource assessments used by the United States Geological Survey are based on deposit models. These assessments consist of three parts: (1) selecting appropriate deposit models and delineating on maps areas permissive for each type of deposit; (2) constructing a grade-tonnage model for each deposit model; and (3) estimating the number of undiscovered deposits of each type. In this article, I focus on the estimation of undiscovered deposits using two methods: the deposit density method and the target counting method. In the deposit density method, estimates are made by analogy with well-explored areas that are geologically similar to the study area and that contain a known density of deposits per unit area. The deposit density method is useful for regions where there is little or no data. This method was used to estimate undiscovered low-sulfide gold-quartz vein deposits in Venezuela. Estimates can also be made by counting targets such as mineral occurrences, geophysical or geochemical anomalies, or exploration "plays" and by assigning to each target a probability that it represents an undiscovered deposit that is a member of the grade-tonnage distribution. This method is useful in areas where detailed geological, geophysical, geochemical, and mineral occurrence data exist. Using this method, porphyry copper-gold deposits were estimated in Puerto Rico. ?? 1993 Oxford University Press.
Prevalence and Associated Factors of Insulin Resistance in Adults from Maracaibo City, Venezuela.
Bermudez, Valmore; Salazar, Juan; Martínez, María Sofía; Chávez-Castillo, Mervin; Olivar, Luis Carlos; Calvo, María José; Palmar, Jim; Bautista, Jordan; Ramos, Eduardo; Cabrera, Mayela; Pachano, Freddy; Rojas, Joselyn
Background and Aim. Insulin resistance (IR) is a prominent pathophysiologic component in a myriad of metabolic disorders, including obesity, prediabetes, and type 2 diabetes mellitus, which are common in our locality. The objective of this study was to determine the prevalence of IR and factors associated with this condition in an adult population from Maracaibo city, Venezuela. Methodology. A cross-sectional, descriptive study with multistaged randomized sampling was carried out in 2026 adults. IR was defined as HOMA2-IR ≥ 2. A multiple logistic regression model was constructed in order to evaluate factors associated with IR. Results. The prevalence of IR was 46.5% (n = 943), with 46.7% (n = 450) in the general population, 46.4% (n = 493) in females, and 47.90% (n = 970) in males (p = 0.895). IR prevalence tended to increase with age and was significantly greater in subjects aged ≥30 years (χ (2) = 16.726; p = 2.33 × 10(-4)). Employment, alcohol consumption, obesity, high triacylglycerides, low HDL-C, and dysglycemia were associated with greater odds of IR, whereas a high level of physical activity appeared to be weak protective factor against IR. Conclusions. The prevalence of IR is elevated in our locality. The main determinants of this condition appear to be the presence of obesity, high triacylglycerides, low HDL-C, dysglycemia, and alcohol intake. PMID:27579182
Geochemical study of the organic matter from Querecual formation, Anzoategui State, Venezuela
Garban, G.; Lopez, L.; Lo Monaco, S.; Lira, A.
Kerogen and bitumen fractions extracted from twenty-one limestone samples from kind section of Querecual formation (Querecual River, Anzoategui State, Venezuela) were analyzed for their content of Co, Cr, Fe, Mn, Mo, Ni, S, Sr, V and Zn. S and trace-metals content from the kerogen fraction were used to obtain information about paleoenvironmental sedimentation conditions of the Querecual formation. Based on these data, and especially on the V and S content variations plus V/Ni, VIV+Ni and Mo/Mo+Cr ratios, we confirm an ancient-reducer condition on this region according with a sulfur-reducer environment. Trace-metals content variations from the bitumen fraction along the study section were used as possible primary migration indicators. V and Ni were the only elements showing a clear tendency to be used as primary migration indicators. The observed tendency allows us to postulate a vertical migration of the bitumen, from center to the extremes of the section.
Steinernema goweni n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from Zulia State, Venezuela.
San-Blas, Ernesto; Morales-Montero, Patricia; Portillo, Edgar; Nermuť, Jiří; Puza, Vladimir
A nematode from the genus Steinernema was isolated in Zulia state (North-western, Venezuela). Morphological, morphometric and molecular studies indicated that this nematode belongs to the "bicornutum" group and is described herein as Steinernema goweni n. sp. Steinernema goweni n. sp. is characterised by morphometrics of its infective juveniles, with body length 640 (531-719) µm, pharynx length of 119 (109-126) µm, tail of 67 (59-89) µm, c ratio = 9 (6-11) and E% = 77 (48-94). First generation male specimens can be recognised by the shape and size of spicules (55 (50-57) µm long) and gubernaculum (35 (30-40) µm long), and %D value 42 (28-59), which is at the lower limit within the "bicornutum" group. The number of genital papillae in males is also distinctive for S. goweni n. sp. presenting up to 27 (13 pairs + 1) papillae in 15% of specimens. The phasmids can be seen in scanning electron microscopy in all stages, characters not previously reported within the "bicornutum" group. Phylogenetic analyses of the "bicornutum" group based on both ITS and D2D3 regions showed a clear separation of S. goweni n. sp. from the other species. In both analyses S. goweni n. sp. formed a strongly supported group of American species. PMID:27395871
Breeding biology and natural history of the Slate-throated Whitestart in Venezuela
Ruggera, R.A.; Martin, T.E.
We provide details on the breeding biology of the Slate-throated Whitestart (Myioborus miniatus) from 126 nests found during seven breeding seasons, 2002-2008, at Yacamb?? National Park, Venezuela. Nesting activity peaked in late April and May. Only the female built the nest and incubated the eggs. Males rarely visited the nest during these stages. Mean clutch size (2.1 ?? 0.04 eggs, n = 93) was the smallest recorded for the Slate-throated Whitestart. Incubation and nestling period lengths were 15.3 ?? 0.31 (n = 21) and 10.8 ?? 0.24 (n = 7) days, respectively. Attentiveness (% of time on the nest) during incubation (59 ?? 1.6%, n = 52) was similar to other tropical warblers and much lower than northern relatives. This caused a relatively low egg temperature (34.40 ?? 0.33u C, n = ?? nests, 20 days) compared with north temperate birds. Both parents fed nestlings and increased their provisioning rates with nestling age. Growth rate based on nestling mass (k = 0.521 ?? 0.015) was faster than for other tropical passerines but slower than northern relatives. Predation was the main cause of nesting failure and rate of predation increased with age of the nest. An estimated 15% of nests were successful based on an overall Mayfield daily predation rate of 0.053 ?? 0.007. This study confirms a strong latitudinal variation in life history traits of warblers. ?? 2010 by the Wilson Ornithological Society.
Geomorphic effects of large debris flows and flash floods, northern Venezuela, 1999
Larsen, M.C.; Wieczorek, G.F.
A rare, high-magnitude storm in northern Venezuela in December 1999 triggered debris flows and flash floods, and caused one of the worst natural disasters in the recorded history of the Americas. Some 15,000 people were killed. The debris flows and floods inundated coastal communities on alluvial fans at the mouths of a coastal mountain drainage network and destroyed property estimated at more than $2 billion. Landslides were abundant and widespread on steep slopes within areas underlain by schist and gneiss from near the coast to slightly over the crest of the mountain range. Some hillsides were entirely denuded by single or coalescing failures, which formed massive debris flows in river channels flowing out onto densely populated alluvial fans at the coast. The massive amount of sediment derived from 24 watersheds along 50 km of the coast during the storm and deposited on alluvial fans and beaches has been estimated at 15 to 20 million m3. Sediment yield for the 1999 storm from the approximately 200 km2 drainage area of watersheds upstream of the alluvial fans was as much as 100,000 m3/km2. Rapid economic development in this dynamic geomorphic environment close to the capital city of Caracas, in combination with a severe rain storm, resulted in the death of approximately 5% of the population (300,000 total prior to the storm) in the northern Venezuelan state of Vargas. ?? 2006 Gebru??der Borntraeger.
The rainfall-triggered landslide and flash-flood disaster in northern Venezuela, December 1999
Larsen, Matthew C.; Wieczorek, Gerald F.; Eaton, L.S.; Heriberto Torres-Sierra
Rainstorms in December 1999 induced thousands of landslides along the northern slopes of the Cordillera de la Costa mountain range principally in the state of Vargas, Venezuela. Rainfall accumulation of 293 millimeters during the first 2 weeks ofDecember was followed by an additional 911 millimeters of rainfall on December 14 through 16. The landslides and floods inundated coastal communities resulting in a catastrophic death toll estimated at between 15,000 and 30,000 people. Debris flow damage to houses, buildings, and infrastructure in the narrow coastal zone was severe. Flash floods on alluvial fans at the mouths of rivers draining the coastal mountain range also contributed to the general destruction. In time scales spanning decades to centuries, the alluvial fans along this Caribbean coastline are areas of high geomorphic activity. Because most of the coastal zone in Vargas consists of steep mountain fronts that rise directly from the Caribbean Sea, the alluvial fans provide the only relatively flat areas upon which to build. Rebuilding and reoccupation of these areas requires careful determination of hazard zones to avoid future loss of life and property. A limited assessment of the distribution and character of landslides is currently in progress by the U.S. Geological Survey in cooperation with the Venezuelan Ministry of Environment and Natural Resources.
Rupture history of the 1997 Cariaco, Venezuela, earthquake from teleseismic P waves
Mendoza, C.
A two-step finite-fault waveform inversion scheme is applied to the broadband teleseismic P waves recorded for the strike-slip, Cariaco, Venezuela, earthquake of 9 July 1997 to recover the distribution of mainshock slip. The earthquake is first analyzed using a long narrow fault with a maximum rise time of 20 sec. This line-source analysis indicates that slip propagated to the west with a constant rupture velocity and a relatively short rise time. The results are then used to constrain a second inversion of the P waveforms using a 60-km by 20-km two-dimensional fault. The rupture shows a zone of large slip (1.3-m peak) near the hypocenter and a second, broader source extending updip and to the west at depths shallower than 5 km. The second source has a peak slip of 2.1 meters and accounts for most of the moment of 1.1 × 1026 dyne-cm (6.6 Mww) estimated from the P waves. The inferred rupture pattern is consistent with macroseismic effects observed in the epicentral area.
Helicobacter pylori Infection in Rural and Urban Dyspeptic Patients from Venezuela.
Contreras, Monica; Fernández-Delgado, Milagro; Reyes, Nelson; García-Amado, María Alexandra; Rojas, Héctor; Michelangeli, Fabian
The goal of this work was to assess the Helicobacter pylori prevalence in a rural mestizo population and compare it to an urban population from Venezuela. The study was performed in gastric juice samples of 71 dyspeptic patients from Caracas (urban) and 39 from Tucupita (rural), in the Orinoco Delta region. Helicobacter pylori was detected by amplification of 16S rRNA, glmM, and ureA genes in 55.0% patients from urban and 87.2% from rural populations. cagA was found positive in 51% and 62% urban and rural patients, respectively. Non-H. pylori Helicobacter species were not detected in the urban population, but was found in 7.7% of patients in the rural study site. Frequency values of the 16S rRNA, glmM, and ureA genes were higher in the rural population. The odds ratio for each gene was 15.18 for 16S rRNA, 2.34 for glmM, 2.89 for ureA, and 1.53 cagA, showing significant differences except for cagA when gene frequency was compared in both populations. These results demonstrate a higher frequency of H. pylori and gastric non-H. pylori Helicobacter infection in a rural mestizo population with low hygienic standards as compared with city dwellers, representing a potential risk for the development of gastroduodenal diseases. PMID:26195456
[Diversity and abundance of mollusks in the sublittoral epifaunal community of Punta Patilla, Venezuela].
Prieto, Antulio; Ruiz, Lilia J; García, Natividad
The diversity of a sublittoral epifaunal mollusk community of Punta Patilla, Sucre State, Venezuela, was studied from September 1990 to September 1991. We identified 25 species (14 bivalves and 11 gastropods) of mollusks that inhabit gravel, soft sand and bottoms covered by Thalassia testudinum. Total diversity indices were H' = 3.42. J' = 0.74 and 1-D = 0.85. Monthly diversity reached its maximum in March 1991 (3.12 bits/ ind.), June 1991 (2.88 bits/ind.) and September 1991 (2.95 bits/ind.); minimum diversity was recorded in August 1991 (1.20 bits/ind.). A log series model showed a diversity index alpha = 4.56 for species abundance data and alpha = 3.11 for biomass data. The more abundant species were Chione cancellata, Anigona listeri, Chione granulata and Area zebra among the bivalves, and Chicoreus brevifrons, Turritella variegata and Phllonotus pomum among the gastropods (which present maximum biomass). The average total biomass (56.80 g/m2) is low when compared to reports from other tropical zones. PMID:17354426
Geology and geochemistry of the La Luna Formation type sections in the Maracaibo basin, Venezuela
Baptista, N.; Scherer, W.
The Upper Cretaceous La Luna Formation is the most important source rock of hydrocarbons in Western Venezuela. Curiously enough it has two type sections, the formation was first defined in 1926 in Perija on the western flank of the Maracaibo basin; 30 years later the La Aguada, Chejende and Timbetes members were defined 260 km toward the east, on the shelf of the basin. The purpose of this study is to compare these sections and to define the vertical and horizontal variability of geological and geochemical characteristics that might have influenced the generation of hydrocarbons. The study consisted of detailed, bed level sampling, macroscopic sedimentary descriptions, petrography of 168 thin sections with 40 variables recorded in a statistical data matrix for determination of lithomicrofacies, as well as geochemical analysis of total organic carbon (TOC), visual kerogen, Rock-Eval pyrolysis and gas chromatography. The western type section is characterized by alternating thinly laminated and massive bedded limestones. Thermally immature, amorphous organic matter of marine origin is abundant in this section; TOC values range from 0.23% to 8.56%, generally increasing toward the top. Hydrogen index values range from 327 to 1078, indicating good to excellent oil generating potential. The eastern type sections have a higher level of thermal maturity; they show increasing amounts of clastic material, less authigenic minerals and abundant Favreina sp crab fecal pellets. The mainly terrestrially derived organic matter concentrations are considerably less, ranging from 0.07 to 3.39, again increasing toward the top of the section.
Organic carbon and phosphate distributions in the La Luna Formation, Western Venezuela
Stoufer, P.S.; Scherer, W.
The Upper Cretaceous La Luna Formation in Western Venezuela is believed to be the major source rock in the Maracaibo basin. In order to obtain an approximation of the total amount of hydrocarbons that could have possibly been generated in this basin, the vertical and areal distribution of total organic carbon (TOC) was studied. Since important phosphate deposits were found in the uppermost portion of the La Luna Formation, their distribution was also determined on a regional scale. A total of 263 samples corresponding to 19 surface sections and 9 wells were collected and analyzed with geochemical methods including LECO carbon analyzer, Rockeval and X-Ray fluorescence. The vertical distribution was represented for all sections and wells. For mapping purposes of TOC and P205 only the upper part of the formation was considered. It was determined, in general, that TOC increases towards the top of the formation; geographically the highest concentrations were found in the central and western part of the Maracaibo basin, close to the Alturitas-Catatumbo area. Higher TOC concentrations correspond to finely laminated limestones and calcareous shales, where bioclasts are more frequent. Phosphates are found only in the uppermost 8-20 m of the stratigraphic section; geographically it is concentrated in northern Tachira and in the central Maracaibo basin. Phosphate is mostly of primary origin, concentrated in massive limestones, glauconitic sandstones and argillaceous rocks. Phosphate mineralogy includes collophane, wavellite and apatite oolites, diagenetic fossil replacements and authigenic precipitates.
Point mutations in dihydrofolate reductase and dihydropteroate synthase genes of Plasmodium falciparum isolates from Venezuela.
Urdaneta, L; Plowe, C; Goldman, I; Lal, A A
The present study was designed to characterize mutations in dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) genes of Plasmodium falciparum in the Bolivar region of Venezuela, where high levels of clinical resistance to sulfadoxine-pyrimethamine (SP, Fansidar; F. Hoffman-La Roche, Basel, Switzerland) has been documented. We used a nested mutation-specific polymerase chain reaction and restriction digestion methods to measure 1) the prevalence of DHFR mutations at 16, 50, 51, 59, 108, and 164 codon positions, and 2) the prevalence of mutations in the 436, 437, 581, and 613 codon sites in DHPS gene. In the case of the DHFR gene, of the 54 parasite isolates analyzed, we detected the presence of Asn-108 and Ile-51 in 96% of the isolates and Arg-50 mutation in 64% of the isolates. Each of these mutations has been associated with high level of resistance to pyrimethamine. Only 2 samples (4%) showed the wild type Ser-108 mutation and none showed Thr-108 and Val-16 mutations that are specific for resistance to cycloguanil. In the case of DHPS gene, we found a mutation at position 437 (Gly) in 100% of the isolates and Gly-581 in 96% of the isolates. The simultaneous presence of mutations Asn-108 and Ile-51 in the DHFR gene and Gly-437 and Gly-581 in the DHPS gene in 96% of the samples tested suggested that a cumulative effect of mutations could be the major mechanism conferring high SP resistance in this area. PMID:10497990
Variation of the vectorial capacity of some anophelines in western Venezuela.
Rubio-Palis, Y
The vectorial capacities of Anopheles nuneztovari, An. albitarsis s.l., and An. triannulatus to transmit Plasmodium vivax in western Venezuela were estimated in different seasons. In general, there was a decrease in the vectorial capacities of the three species during the dry season, which seems to be due mainly to a reduction in the mosquito biting populations. Comparing the observations made during the two wet seasons, there was a decrease in the vectorial capacities of the three species due to different factors for each species. In An. nuneztovari, the reduction in vectorial capacity seems to be due to a reduction in the human blood index (HBI); in An. albitarsis, it is probably due to a reduction in the HBI and a slight reduction in parity, whereas in An. triannulatus, the cause is probably a reduction in the mosquito biting population and in parity. The overall reduction in vectorial capacities of the three anopheline species in 1989 compared with the vectorial capacities in 1988 could partly explain the marked reduction in prevalence from 46.2 per 1,000 population in 1988 to 7.5 per 1,000 population in 1989. PMID:8166348
Biting and resting behaviour of anophelines in western Venezuela and implications for control of malaria transmission.
Rubio-Palis, Y; Curtis, C F
A study was conducted in three villages in western Venezuela between February 1988 and October 1989 to determine the biting and resting activity of anophelines in relation to human habits, rainfall and fenitrothion spraying of houses. Mosquitoes were collected landing on humans inside and outside experimental huts throughout the night. Only three mosquitoes were found resting in the huts in the morning, but 2470 were collected resting on vegetation in the early morning. The collections yielded eleven species of anopheline, the most abundant being Anopheles nuneztovari, comprising over 75% of the total anophelines collected, followed by An.triannulatus, An.albitarsis s.l. and An.oswaldoi. The four most abundant species showed different diel patterns of biting. For An.nuneztovari the peak of activity was close to midnight indoors and outdoors, for An.triannulatus between 19.00 and 20.00 hours outdoors, for An.albitarsis mainly before midnight indoors and outdoors and for An.oswaldoi outdoors at 19.00 hours, with an additional smaller peak indoors at midnight. Most of the human population use bednets, go to bed before 22.00 hours and are therefore most exposed to mosquitoes that bite outdoors early in the night. Fenitrothion house-spraying failed to prevent large mosquito populations developing in the wet season, presumably because of their exophilic resting habits. The possible advantages of impregnation of existing bednets with pyrethroids, and provision of nets for people who do not have them, are discussed. PMID:1463897
Paleogeographic considerations of the Barbacoas Platform western border during Paleocene-Middle Eocene, Trujillo State, Venezuela
Muller, K. ); Falcon, R. )
Stratigraphic and sedimentological field information of the Chejende-Cuicas area, and subsurface well data (Butaque-1S) have been integrated to analyze the paleogeographic evolution of Barbacoas Platform. Both localities are in the Trujillo state, western Venezuela and they are 18 km apart. A relatively narrow continental platform during Paleocene times can be inferred from the existence of Paleocene rocks of the Rancheria Formation, deposited in outer and middle neritic environments. This formation probably grades laterally towards the east and northeast, into the Trujillo Formation (Paleocene-early Eocene), which was deposited in a middle to upper bathyal environment in turbiditic conditions. Paleocene units grade upwards into the Misoa Formation, deposited in deltaic to coastal marine environments. This suggests a regressive progradation over slope and platform during early to early middle Eocene times. Eocene sedimentation ends with the transgressive Caus and Pauji formations, typical of upper bathyal to outer neritic conditions. Low sedimentation and subsidence rates in the platform in the Chejende area is inferred by the marked difference between Rancheria and Misoa formation thicknesses in this area (95 m and 40 m) and the Butaque-S well (520 and 175 m).
Monitoring coastal pollution associated with the largest oil refinery complex of Venezuela.
Croquer, Aldo; Bone, David; Bastidas, Carolina; Ramos, Ruth; García, Elia
This study evaluated pollution levels in water and sediments of Península de Paraguaná and related these levels with benthic macrofauna along a coastal area where the largest Venezuelan oil refineries have operated over the past 60 years. For this, the concentration of heavy metals, of hydrocarbon compounds and the community structure of the macrobenthos were examined at 20 sites distributed along 40 km of coastline for six consecutive years, which included windy and calm seasons. The spatial variability of organic and inorganic compounds showed considerably high coastal pollution along the study area, across both years and seasons. The southern sites, closest to the refineries, had consistently higher concentrations of heavy metals and organic compounds in water and sediments when compared to those in the north. The benthic community was dominated by polychaetes at all sites, seasons and years, and their abundance and distribution were significantly correlated with physical and chemical characteristics of the sediments. Sites close to the oil refineries were consistently dominated by families known to tolerate xenobiotics, such as Capitellidae and Spionidae. The results from this study highlight the importance of continuing long-term environmental monitoring programs to assess the impact of effluent discharge and spill events from the oil refineries that operate in the western coast of Paraguaná, Venezuela. PMID:27375970
Prevalence and Associated Factors of Insulin Resistance in Adults from Maracaibo City, Venezuela
Palmar, Jim; Cabrera, Mayela
Background and Aim. Insulin resistance (IR) is a prominent pathophysiologic component in a myriad of metabolic disorders, including obesity, prediabetes, and type 2 diabetes mellitus, which are common in our locality. The objective of this study was to determine the prevalence of IR and factors associated with this condition in an adult population from Maracaibo city, Venezuela. Methodology. A cross-sectional, descriptive study with multistaged randomized sampling was carried out in 2026 adults. IR was defined as HOMA2-IR ≥ 2. A multiple logistic regression model was constructed in order to evaluate factors associated with IR. Results. The prevalence of IR was 46.5% (n = 943), with 46.7% (n = 450) in the general population, 46.4% (n = 493) in females, and 47.90% (n = 970) in males (p = 0.895). IR prevalence tended to increase with age and was significantly greater in subjects aged ≥30 years (χ2 = 16.726; p = 2.33 × 10−4). Employment, alcohol consumption, obesity, high triacylglycerides, low HDL-C, and dysglycemia were associated with greater odds of IR, whereas a high level of physical activity appeared to be weak protective factor against IR. Conclusions. The prevalence of IR is elevated in our locality. The main determinants of this condition appear to be the presence of obesity, high triacylglycerides, low HDL-C, dysglycemia, and alcohol intake. PMID:27579182
[Mosquito fauna (Diptera:Culicidae) from Falcon State, Venezuela. I. New records and current checklist].
Navarro, J C; Bastidas, R J; Zavala, Y
A total of 16 new species records of Culicidae from Falcon State was collected at the "Juan Crisostomo Falcon National Park" (Sierra de San Luis), Natural Monument "Cerro Santa Ana", Coro, and La Vela. Species of Sabethini, Culicini and Toxorhynchitini Tribes were found in natural breeding sites (Phytotelmata), with special occurrence in plants belonging to Tillandsia, Vriesea, Guzmania, Aechmea (Bromelianceae), Heliconia (Heliconiaceae), Calathea (Marantaceae) and Colocasia (Araceae). Aedini and Mansonini were collected only as adults. A specie of Culex (Carrollia) was collected from an artificial container. The Culicidae species belong to 6 genera out of the 23 genera reported from Venezuela (Culex, Wyeomyia, Johnbelkinia, Aedes, Psorophora, Mansonia and Coquillettidia) and to 5 Tribes out of the 9 present in the country. The Aedini, Sabethini and Culicini Tribes were richer in species with 5, 4 and 4 species, respectively, than the Mansonini (2 species) and Toxorhynchitini (1 species) Tribes. We discuss some bioecological aspects regarding the 16 new-species records in Falcon State and give a checklist of the mosquito species previously reported in the literature. PMID:9239851
Biostratigraphy of a Middle Miocene-Pliocene sequence from Cumarebo area, Falcon State, northwestern Venezuela
Giffuni, G. )
The southern Caribbean region offers little in the way of continuous sequences for the late Neogene. An upward facies shallowing trend unfavorable for planktonic foraminifers and erosional truncation seems to be almost a rule for such sediments. A fairly complete sedimentary sequence mainly represented by clays, silts, and carbonate rocks from the Cumarebo region, Falcon State, northwestern Venezuela, was chosen to study the biostratigraphy of the late Neogene using foraminifers. More than one hundred surface samples were analyzed throughout. The study of foraminiferal fossil assemblages and other microfossils was also used to define paleoenvironments of deposition. Four formations are involved in this work. From base to top they are the Socorro, Caujarao, El Veral, and Tucupido. From the study of planktonic foraminifers, six biostratigraphic zones were recognized: Globorotalia mayeri Zone, Globorotalia menardii Zone, Globorotalia acostaensis Zone, Globorotalia humerosa Zone, Globorotalia margaritae Zone, and Globorotalia miocenica Zone. These zones indicate that the age of the sequence ranks from late middle Miocene to middle Pliocene. Generally speaking, with some variations, the paleoenvironments of the sequence show a shallowing trend from marine upper-middle bathyal to middle neritic. These results make an important contribution to the stratigraphy and geologic history of the Cumarebo area, which is related to the Agua Salada basin, and may help clarify the paleogeography and paleotectonic evolution of this region for petroleum exploration.
Malaria Control in Amerindian Communities of Venezuela : Strengthening Ecohealth Practice Throughout Conservation Science and Capability Approach.
Bevilacqua, Mariapia; Rubio-Palis, Yasmin; Medina, Domingo A; Cárdenas, Lya
Adaptive management and ecohealth frameworks were developed for malaria elimination in Amerindian riparian communities of Venezuela. These frameworks were developed as a strategy to capture, organize, and communicate connections among key factors related to local malaria complex systems. Important causal relationships between social, economic, and environmental stressors which are determinant of malaria were identified at different levels and assumptions that guide interventions are offered, based on available scientific knowledge and input from stakeholders. Drawing on our experience of action research committed to the health of Amerindian populations and conservation of areas with biodiversity value, the authors provide lessons to strengthen the practice of an ecohealth approach. First, conservation targets were considered as a way to achieve sustainable human well-being rather than as a consequence of well-being. Second, the effectiveness and sustainability of technical solutions generally proposed for malaria control depend largely on individual knowledge, attitudes, and practices. Hence, it is necessary to look at the real opportunities of choices that Amerindian people have for attaining a life without malaria, and therefore pay attention to local capabilities, needs, and freedom to choose. The ecohealth approach can benefit from the capability approach, and we explain why. PMID:25851195
Malaria entomological risk factors in relation to land cover in the Lower Caura River Basin, Venezuela.
Rubio-Palis, Yasmin; Bevilacqua, Mariapia; Medina, Domingo Alberto; Moreno, Jorge Ernesto; Cárdenas, Lya; Sánchez, Víctor; Estrada, Yarys; Anaya, William; Martínez, Ángela
To explore the effects of deforestation and resulting differences in vegetation and land cover on entomological parameters, such as anopheline species composition, abundance, biting rate, parity and entomological inoculation rate (EIR), three villages were selected in the Lower Caura River Basin, state of Bolívar, Venezuela. All-night mosquito collections were conducted between March 2008-January 2009 using CDC light traps and Mosquito Magnet® Liberty Plus. Human landing catches were performed between 06:00 pm-10:00 pm, when anophelines were most active. Four types of vegetation were identified. The Annual Parasite Index was not correlated with the type of vegetation. The least abundantly forested village had the highest anopheline abundance, biting rate and species diversity. Anopheles darlingi and Anopheles nuneztovari were the most abundant species and were collected in all three villages. Both species showed unique biting cycles. The more abundantly forested village of El Palmar reported the highest EIR. The results confirmed previous observations that the impacts of deforestation and resulting changes in vegetation cover on malaria transmission are complex and vary locally. PMID:23579803
Simulium metallicum cytospecies E larval habitat characterization in the Altamira focus of onchocerciasis, northern Venezuela.
Grillet, M E; Barrera, R; Conn, J
Simulium metallicum sibling species E was identified cytotaxonomically from an onchocerciasis focus at Altamira in northern Venezuela. S. metallicum E larvae were sampled monthly from two small mountain streams over a 15-month period (July 1990 to September 1991) and eleven habitat variables were measured at two altitudes. One stream consistently harboured much higher densities of S. metallicum E larvae than the other, with three annual peaks of abundance: during the dry season and at the beginning and end of the rainy season. These peak densities were correlated with high rainfall 4 months previously. Larvae were most abundant on submerged rocks and fallen leaves, in small shallow areas characterized by slow water current, high conductivity and sparse terrestrial vegetation cover. Stream variables which best explained the temporal changes in abundance were water discharge and conductivity. The population dynamics of S. metallicum E appeared to be influenced primarily by interactions between stream discharge and substrate stability. Relevance of these results to vector control with larvicides is discussed. PMID:7787229
Development of Caribbean plate tectonics: A contribution from oil exploration in Venezuela
Fuentes, J. ); Oum, S. ); Lander, R. )
Following several huge oil and gas discoveries during the mid-1980s in the Northern Venezuela overthrust belt more detailed geological and geophysical studies have increased their perception of structural control on sedimentary basin development. Significant improvements in seismic data quality and seismic lines positioned close to outcrops of the frontal thrust give evidence of Miocene to Pleistocene thin-skinned tectonics as the mechanism of the formation of the overthrust belt of the Serrania del Interior. The authors conclude that the thrust sheet was formed by the effects of major right-lateral transcurrent movements along the El Pilar fault system, which forced metasediments against thick Miocene clastics in pull-apart basins. These basins were created earlier by strike-slip motions of preexisting parallel en-echelon normal faults. The eastwardly mobile Caribbean plate boundary and its evolution from a collision to a transpression zone is documented and a new approach to an evaluation of oil and gas potential is made of multiple reservoirs in stacked, folded thrust sheets.
Geological Studies in eastern Venezuela and Trinidad from Cretaceous passive margin to Neogene transpressional thrust belt
Algar, S.T.; Erikson, J.E.; Pindell, J.L. )
Sedimentological and structural analyses of Trinidad's Northern and Central ranges and Venezuela's Serrania del Interior have led to new interpretations of northeastern. South America's tectonic evolution within the Southern Caribbean Plate Boundary Zone. Medial ( ) Jurassic through early Cenozoic passive margin sediments make up the majority of these areas and were deposited somewhat to the WNW (between 80 and 130 km for Northern Range of Trinidad) of their present positions prior to structural shortening. Neogene southeastward displacement of Jurassic-Cretaceous passive slope and rise sediments (Northern Range) drove propagation of thrusts southward into the Serrania and Central ranges. Displacements were driven by migration of the Caribbean Plate relative to South America. Thus, the Serrania and Central ranges are the western hemisphere's only exposed Mesozoic-Cenozoic passive Atlantic margin stratigraphic section. As such, they provide a Cretaceous-Paleogene record of passive margin sedimentation at a thermally subsiding margin where the complicating effects of tectonism are absent. This makes these sections especially suited for studies of eustatic sea level behavior. Preliminary assessments are shown which suggest that sea level changes for Cretaceous to Paleogene time are not as pronounced as the frequent large and rapid sea level falls and rises that are promoted by some.
Prevalence of erectile dysfunction in Colombia, Ecuador, and Venezuela: a population-based study (DENSA).
Morillo, L E; Díaz, J; Estevez, E; Costa, A; Méndez, H; Dávila, H; Medero, N; Rodriguez, N; Chaves, M; Vinueza, R; Ortiz, J A; Glasser, D B
The purpose of this study was to estimate the prevalence of erectile dysfunction (ED) in Colombia, Ecuador, and Venezuela. A 49-item questionnaire was completed by 1946 men aged 40 years and older. The age-adjusted combined prevalence of minimal, moderate, and complete ED for all three countries was 53.4%, with 19.8% of all men reporting moderate to complete ED. Age was the variable most strongly linked to ED; the prevalence of complete ED increased markedly in men older than 79 y of age (31.9%) and 70-79 y (17.2%) compared with men aged 40-49 y (<3%). Several medical conditions, such as hypertension, benign prostatic hyperplasia, and diabetes, and the use of medications to treat these conditions were correlated with the prevalence of ED. This study corroborates earlier studies demonstrating that ED is very common, increases dramatically with age, and has multiple correlates, including some that are also risk factors for cardiovascular disease. PMID:12161763
Giant discoveries in Monagas overthrust belt, eastern Venezuela basin, 1987-1988
Aymard, R.; Pemental, L.; Lopez, P.; Chaouch, A.
Two deep wildcats drilled on the northern flank of the Eastern Venezuela basin have tested large quantities of medium to light oil from massive Eocene and Oligocene sands. The wells, drilled in the Musipan and Carito areas, tested between 5000 and 10,000 bbl of 26/degrees/-34/degrees/ API gravity crude from the Caratas, Los Jabillos, and Naricual Formations; net oil sand for each well exceeded 500 m, with average porosities of 14%. The structures found in the Monagas overthrust belt consist of east-west-trending anticlines associated with overthrust faulting. The surface area of the structures is 100 km/sup 2/, which includes the Furrial field. Vertical closure exceeds 1000 m. The thick, subcompacted Carapite Formation shales form a very effective vertical seal. The cenomanian-Turoniam Querecual shales are the source rock for most of the oil found in the area. Of the 12 prospective areas identified, two have been tested and three are being drilled. Delineation drilling has already begun on the newly discovered structures, and over 6 billion bbl of oil are expected to be found, making this area one of the largest oil plays in Latin America and in the Western Hemisphere.
Update on oral Chagas disease outbreaks in Venezuela: epidemiological, clinical and diagnostic approaches
de Noya, Belkisyolé Alarcón; Díaz-Bello, Zoraida; Colmenares, Cecilia; Ruiz-Guevara, Raiza; Mauriello, Luciano; Muñoz-Calderón, Arturo; Noya, Oscar
Orally transmitted Chagas disease has become a matter of concern due to outbreaks reported in four Latin American countries. Although several mechanisms for orally transmitted Chagas disease transmission have been proposed, food and beverages contaminated with whole infected triatomines or their faeces, which contain metacyclic trypomastigotes of Trypanosoma cruzi, seems to be the primary vehicle. In 2007, the first recognised outbreak of orally transmitted Chagas disease occurred in Venezuela and largest recorded outbreak at that time. Since then, 10 outbreaks (four in Caracas) with 249 cases (73.5% children) and 4% mortality have occurred. The absence of contact with the vector and of traditional cutaneous and Romana's signs, together with a florid spectrum of clinical manifestations during the acute phase, confuse the diagnosis of orally transmitted Chagas disease with other infectious diseases. The simultaneous detection of IgG and IgM by ELISA and the search for parasites in all individuals at risk have been valuable diagnostic tools for detecting acute cases. Follow-up studies regarding the microepidemics primarily affecting children has resulted in 70% infection persistence six years after anti-parasitic treatment. Panstrongylus geniculatus has been the incriminating vector in most cases. As a food-borne disease, this entity requires epidemiological, clinical, diagnostic and therapeutic approaches that differ from those approaches used for traditional direct or cutaneous vector transmission. PMID:25946155
A new species of Caligus (Copepoda, Siphonostomatoida) from the plankton of the Caribbean coast of Venezuela with a key to species
Suárez-Morales, Eduardo; Camisotti, Humberto; Martín, Alberto
Abstract During a survey of the zooplankton community of Bahía Amuay, Venezuelan Caribbean, specimens of an undescribed species of Caligus Müller were collected. It resembles Caligus xystercus Cressey and Caligus ocyurus Cressey, both known only from the Caribbean Sea. The new species can be distinguished from these and other congeners by a combination of characters including the armature of legs 1 and 4, but mainly by its unique female genital complex. This is the first species of Caligus described from Venezuela. The species is described in full and a key to the species of the genus recorded in Venezuela is provided. PMID:22768004
Preliminary inventory of mammals from Yurubí National Park, Yaracuy, Venezuela with some comments on their natural history.
García, Franger J; Delgado-Jaramillo, Mariana; Machado, Marjorie; Aular, Luis
In Venezuela, mammals represent an important group of wildlife with high anthropogenic pressures that threaten their permanence. Focused on the need to generate baseline information that allows us to contribute to document and conserve the richness of local wildlife, we conducted a mammalogical inventory in Yurubí National Park, located in Yaracuy State in Venezuela. We carried out fieldworks in three selected vegetation types: an evergreen forest at 197m, a semi-deciduous forest ranging between 100-230m, and a cloud forest at 1 446m. We used Victor, Sherman, Havahart and pitfall traps for the capture of small non-volant mammals and mist nets for bats. In addition, we carried out interviews with local residents and direct-indirect observations for medium-large sized mammals. At least 79 species inhabit the area, representing 28% of the species recorded for the North side of the country. Chiroptera (39 spp.), Carnivora (13 spp.) and Rodentia (9 spp.) were the orders with the highest richness, as expected for the Neotropics. The evergreen forest had the greatest species richness (n=68), with a sampling effort of 128 net-hours, 32 bucket-days, 16 hours of observations, and three persons interviewed, followed by cloud forest (n=45) with 324 net-hours, 790 traps-night, 77 bucket-days, 10 hours of observations, and one person interviewed. The lowest richness value was in the semi-deciduous forest (n=41), with 591 traps-night, 15 net-hours, 10 hours of observations and three persons interviewed. Data and observations obtained in this inventory (e.g., endemism, species known as "surrogate species" threatened in Venezuela) give an important role at the Yurubí National Park in the maintenance and conservation of local ecosystems and wildlife, threatened by human pressures in the Cordillera de la Costa. PMID:22458239
Environmental exposure to mercury in the urban area of Alta Floresta
Hacon, S.; Rochedo, E.R.R.; Calysto, R.R.; Lacerda, L.D.
Mercury has been released into the Amazonia ecosystem as a result of gold mining activities over the past 15 years. Metallic mercury is used to amalgamate gold particulate. During the amalgamation process, a significant amount of metallic Hg finds its way into the aquatic and terrestrial systems. About 65 to 83% of the total mercury emission by gold mining activities enters directly into the atmosphere. The inorganic Hg is then methylated by microbiota and the organic Hg is bioaccumulated within the aquatic food chain, from which humans are a top predator. Alta Floresta is the most important gold trading center in Amazonia. The urban population is exposed to a high concentration of Hg in the atmosphere, ranging from 23 to 5,788 ng/m{sup 3}. Also the mercury levels in fishes eaten locally are high, mainly in fish from Teles Pires river. Nine from the eleven species most consumed by the urban population are carnivorous, and constitute about 98% of all fish eaten locally. The highest Hg levels are found in Brachyplastistoma sp. (Piraiba), ranging from 1.7 to 3.0 {mu}g/g (w.w.) and Paulicea Luetkin (Jau), ranging from 0.4 to 2.7 {mu}g/g (w. w.) assuming an average fish consumption rate of 31 grams per day, an weighted average of Hg fish concentration of 1.2 {mu}g/g, an average body weight for adults of 60 kg and an average exposure duration of 8 years, the estimated incorporation 0.63 pg of Hg per kg of body weight would imply that attention should be given to the critical groups such as children and woman in the child-bearing age, since fetus are more sensitive to mercury than adults.
Wet Conditions during the Last Glaciation in the Chihuahuan Desert, Alta Babicora Basin, Mexico
NASA Astrophysics Data System (ADS)
Metcalfe, Sarah; Say, Alison; Black, Stuart; McCulloch, Robert; O'Hara, Sarah
A 467-cm core (B94/3) from the Alta Babicora basin in the Chihuahuan Desert, northern Mexico (29°N, 108°W), documents lake-level and climate changes over the past ca. 65,000 yr. Chronological control is provided by four accelerator mass spectrometry 14C dates and five U-series dates on diatom silica. The core has been analyzed for magnetic susceptibility, loss-on-ignition, carbonate content, sediment chemistry and mineralogy, and pollen and diatom composition. The basin was occupied by a deep freshwater lake throughout the late Pleistocene which, based on shoreline evidence, was at least 19 m deeper than today. The lake shallowed after ca. 57,000 yr B.P. High variability typified the period between 54,600 and 38,000 yr B.P., probably with periodic desiccation and deflation. A deep-water lake was reestablished after 38,000 yr B.P. and persisted until ca. 29,000 yr B.P. Shallowing occurred through the last glacial maximum, although the lake was still deeper than at present. The Pleistocene-Holocene transition was marked by a distinctive change in the diatom flora. There is no diatom record for much of the Holocene, but other proxies indicate generally dry, stable catchment conditions. The Babicora record is more akin to those from the southwest United States than it is to Central America and northern South America. Wet conditions in the late Pleistocene are attributed to winter rainfall from midlatitudes in contrast to the modern, tropical, summer rainfall regime.
Adaptation of rainfed agriculture to climatic variability in the Mixteca Alta Region of Oaxaca, Mexico
NASA Astrophysics Data System (ADS)
Rogé, P.; Friedman, A. R.; Astier, M.; Altieri, M.
The traditional management systems of the Mixteca Alta Region of Oaxaca, Mexico offer historical lessons about resilience to climatic variability. We interviewed small farmers to inquire about the dynamics of abandonment and persistence of a traditional management systems. We interpret farmers' narratives from a perspective of general agroecological resilience. In addition, we facilitated workshops in small farmers described their adaptation to past climate challenges and identified 14 indicators that they subsequently used to evaluate the condition of their agroecosystems. The most recent years presented increasingly extreme climatic and socioeconomic hardships: increased temperatures, delayed rainy seasons, reduced capacity of soils to retain soil moisture, changing cultural norms, and reduced rural labor. Farmers reported that their cropping systems were changing for multiple reasons: more drought, later rainfall onset, decreased rural labor, and introduced labor-saving technologies. Examination of climate data found that farmers' climate narratives were largely consistent with the observational record. There have been increases in temperature and rainfall intensity, and an increase in rainfall seasonality that may be perceived as later rainfall onset. Farmers ranked landscape-scale indicators as more marginal than farmer management or soil quality indicators. From this analysis, farmers proposed strategies to improve the ability of their agroecosystems to cope with climatic variability. Notably, they recognized that social organizing and education are required for landscape-level indicators to be improved. Transformative change is required to develop novel cropping systems and complementary activities to agriculture that will allow for farming to be sustained in the face of these challenges. Climate change adaptation by small farmers involves much more than just a set of farming practices, but also community action to tackle collective problems.
A distinctive new subspecies of Scytalopusgriseicollis (Aves, Passeriformes, Rhinocryptidae) from the northern Eastern Cordillera of Colombia and Venezuela.
Avendaño, Jorge Enrique; Donegan, Thomas M
We describe a new subspecies of Pale-bellied Tapaculo Scytalopusgriseicollis from the northern Eastern Cordillera of Colombia and Venezuela. This form differs diagnosably in plumage from described subspecies Scytalopusgriseicollisgriseicollis and Scytalopusgriseicollisgilesi and from the latter in tail length. It is also differentiated non-diagnosably in voice from both these populations. Ecological niche modelling analysis suggests that the new subspecies is restricted to the Andean montane forest and páramo north of both the arid Chicamocha valley and the Sierra Nevada del Cocuy. PMID:26085800
A new species of small-eared shrew from Colombia and Venezuela (Mammalia: Soricomorpha: Soricidae: Genus Cryptotis)
Woodman, N.
Populations of small-eared shrews inhabiting the northern Cordillera Oriental of Colombia and adjoining Venezuelan highlands in the vicinity of Paramo de Tama have been referred alternatively to Cryptotis thomssi or Cryptotis meridensis. Morphological and morphometrical study of this population indicates that it belongs to neither taxon, but represents a distinct, previously unrecognized species. I describe this new species as Cryptotis tamensis and redescribe C. meridensis. Recognition of the population at Paramo de Tama as a separate taxon calls into question the identities of populations of shrews currently represented only by single specimens from Cerro Pintado in the Sierra de Perija, Colombia, and near El Junquito in the coastal highlands of Venezuela.
A distinctive new subspecies of Scytalopus griseicollis (Aves, Passeriformes, Rhinocryptidae) from the northern Eastern Cordillera of Colombia and Venezuela
Avendaño, Jorge Enrique; Donegan, Thomas M.
Abstract We describe a new subspecies of Pale-bellied Tapaculo Scytalopus griseicollis from the northern Eastern Cordillera of Colombia and Venezuela. This form differs diagnosably in plumage from described subspecies Scytalopus griseicollis griseicollis and Scytalopus griseicollis gilesi and from the latter in tail length. It is also differentiated non-diagnosably in voice from both these populations. Ecological niche modelling analysis suggests that the new subspecies is restricted to the Andean montane forest and páramo north of both the arid Chicamocha valley and the Sierra Nevada del Cocuy. PMID:26085800
Isolation of Madre de Dios Virus (Orthobunyavirus; Bunyaviridae), an Oropouche Virus Species Reassortant, from a Monkey in Venezuela.
Navarro, Juan-Carlos; Giambalvo, Dileyvic; Hernandez, Rosa; Auguste, Albert J; Tesh, Robert B; Weaver, Scott C; Montañez, Humberto; Liria, Jonathan; Lima, Anderson; Travassos da Rosa, Jorge Fernando Soares; da Silva, Sandro P; Vasconcelos, Janaina M; Oliveira, Rodrigo; Vianez, João L S G; Nunes, Marcio R T
Oropouche virus (OROV), genus Orthobunyavirus, family Bunyaviridae, is an important cause of human illness in tropical South America. Herein, we report the isolation, complete genome sequence, genetic characterization, and phylogenetic analysis of an OROV species reassortant, Madre de Dios virus (MDDV), obtained from a sick monkey (Cebus olivaceus Schomburgk) collected in a forest near Atapirire, a small rural village located in Anzoategui State, Venezuela. MDDV is one of a growing number of naturally occurring OROV species reassortants isolated in South America and was known previously only from southern Peru. PMID:27215299
Geochronology of recent sediments from the Cariaco Trench (Venezuela) by Alpha Spectrometry of {sup 210}Pb ({sup 210}Po)
Arriojas, A.; Barros, H.; Palacios, D.; Sajo-Bohus, L.; Hurtado, S.; Villa, M.; Perez, K.; Alfonso, J.
210Pb concentration in marine sediments of the Cariaco Trench (North-East of Venezuela) was measured through the analysis of 210Po alpha emissions, which can be assumed to be in secular equilibrium with 210Pb. The analysed sediment core has a length of 1.9 m. The results allowed to apply the CF:CS dating model (Constant Flux and Constant Supply). The sedimentation rate was estimated to be 0.25 cm/y. As far as we know this is the first {alpha}- dating carried out in the country, performed with an alpha spectrometer recently funded by the IAEA.
Politics of oil in Venezuela: A decision-making analysis of PDVSA's internationalisation policy
NASA Astrophysics Data System (ADS)
Baena, Cesar E.
The high degree of international vertical integration achieved by the Venezuelan state oil enterprise, Petroleos de Venezuela S.A. (PDVSA), has placed it among the most important oil multinationals (MNs). The policy of creating downstream outlets through the establishment of foreign direct investments (FDIs) in the form of refinery assets was given the term of 'internationalisation'. By analysing PDVSA's internationalisation policy, the thesis explores the difficulties encountered by a major state-owned enterprise (SOE) from a developing country in its efforts to grow beyond national borders. The study focuses on the impact of democratic bargaining on the process of oil policymaking in Venezuela, stressing the constraints posed by politics on PDVSA's efforts to expand its foreign operations. Specifically, the study examines the intricate policymaking process that shaped the origins and the development of PDVSA's internationalisation policy, underlying the events and factors that influenced each one of its three distinguishable phases: adoption, formulation, and implementation. The tensions between politics and corporate strategy are highlighted at the core of the policymaking process. The study also looks at the relationship between the oil industry and the other two key decision-making centres involved in the oil policymaking process: the executive and Congress. In exploring the ways in which each one of them sought to influence policy outcome, the study attempts to gain insight into the main factors that prompted the tensions among the policy actors involved. Three environments, or pressure-generating centres, constantly exert influence on the oil industry: the oil market, the political context and the government's financial situation. By seeking to determine the industry's response to their pervasive influence on policy formulation and implementation, this research ascertains the extent to which these variables influenced the decision-making process that
The Boscan Field-Venezuela's giant stratigraphic trap with a complex history
Swanson, D.C. ); Jaimes, J.; Valdez, C.; Pirela, B.; Puche, F.; Rojas, D.; Moya, E. )
The Boscan Field lies in the northwest quadrant of the Maracaibo Basin, Venezuela. It is a large stratigraphic trap that has produced more than 800 million barrels of heavy oil since 1946, principally from Eocene fluvial-deltaic clastic reservoirs. These are faulted, folded, and are truncated by a pre-Oligocene unconformity. The geochronology of the Boscan Field has been interpreted as follows: (1) Eocene fluvial-deltaic deposits prograded east and southeast across the Boscan Field Area. A subsiding area northeast towards the State of Falcon received tremendous quantities of Eocene fine grained organic-rich deposits in pro-delta and deep water environments. (2) The Eocene shales in the deep basin began to generate hydrocarbons which migrated towards the west and southwest. (3) In the Boscan Area, Eocene deposits were folded, faulted, and tilted towards the east and southeast and an active fluvial flood-plain truncated the deposits resulting in subcrop bands that form the pre-Oligocene unconformity topographic surface. (4) Hydrocarbon generation and migration continues in the deep basin. (5) Oligocene fluvial sandstones deposited on the underlying unconformity often cut into and are in direct contact with truncated Eocene sandstones. This allowed some oil to leak up into the Oligocene deposits. (6) By the end of the Oligocene, migration of oil into the gross Boscan trap was well underway. The east-west and northwest southeast trending fluvial conduits carried the oil out of the Eocene basin northwestward until it was blocked by reservoir truncation on the west and northwest sides of the Boscan Field. (7) Regional subsidence of the Maracaibo Basin has caused the Boscan reservoirs to dip towards the southwest resulting in realignment of fluids. The present-day Boscan Field is a composite of stacked, linear, faulted, and truncated reservoir segments. They may be isolated or interactive with other segments and form a complex [open quotes]plumbing[close quotes] tangle.
[Vertebrate mortality in the Guanare-Guanarito road, Portuguesa state, Venezuela].
Seijas, Andrés Eloy; Araujo-Quintero, Alexis; Velásquez, Nadines
Roads directly or indirectly affect the structure, dynamics and function of ecosystems that they traverse. Most studies on the effect of roads on wildlife focus on the evaluation of mortality of vertebrates by vehicle collisions. Despite the extensive road network that exists in Venezuela, studies of wildlife mortality in them are scarce. In this paper, we analyzed the temporal and spatial pattern of vertebrate's collisions along the road Guanare-Guanarito, in Portuguesa state. We travelled 26 times between these towns (74 km) to localize dead vertebrates, at a speed of 50-60km/h. of those trips were conducted from March 13 to October 26, 2010, and 10 additional trips from December 7, 2009 to December 14, 2010; these ones, with the aim to include months and seasons that were insufficiently sampled during the first period. The elapsed time between trips varied from 14 to 37 days. The total distance traveled was 1 924 km. Dead animals found amounted 464 individuals, 66 of them were birds (25 identified species), 130 mammals (15 species) and 268 reptiles (18 species). The species with the highest number of individuals were the snake Leptodeira annulata (n=119), the oppossum Didelphis marsupialis (n=39) and the spectacled caiman Caiman crocodilus (n=33). Excluding domestic animals, the rate of road-killed vertebrates was 0.2282 indiv./km, a figure 28.3% higher than previous studies in the same road. Changes in the relative number of collisions for some species, respect to the numbers reported 20 years ago, were linked to the increase in traffic flow and changes in land use. Road segments with collision rates higher than expected by chance were identified. Collition by cars may be the principal cause of mortality for species like the tamandua (Tamandua tetradactyla) and the giant anteater (Myrmecophaga tridactyla), the last considered a vulnerable species. Some basic measures are proposed to reduce wildlife mortality on the road. PMID:24432523
Chagas' disease: an emergent urban zoonosis. The caracas valley (Venezuela) as an epidemiological model.
Urdaneta-Morales, Servio
The unprecedented emergence of important public health and veterinary zoonoses is usually a result of exponential population growth and globalization of human activities. I characterized Chagas' disease as an emergent zoonosis in the Caracas Valley (Venezuela) due to the following findings: the presence of reservoirs (Didelphis marsupialis, Rattus rattus) and vectors (Panstrongylus geniculatus, Panstrongylus rufotuberculatus) infected with Trypanosoma cruzi in urbanized or marginalized areas; the elevated contact between P. geniculatus and human beings detected by parasitological and molecular examinations of triatomine feces demonstrated the possibility of transmission risks; a study of outbreaks of urban Chagas' disease reported the first proven case of oral transmission of T. cruzi to human beings; the risk of transmission of glandular metacyclic stages from marsupials by experimental ocular and oral instillation; mice genitalia infected with T. cruzi contaminated blood resulted in the formation of amastigotes very close to the lumen suggesting that there may be a possibility of infection via their release into the urine and thence to the exterior; the ubiquitous histotropism and histopathology of T. cruzi was demonstrated using a mouse model; the presence of experimental T. cruzi pseudocysts in adipose, bone-cartilage, and eye tissue indicated a potential risk for transplants. Socio-sanitary programs that include improvements in housing, vector control, and access to medical treatment, as well as strategies aimed at combating social inequalities, poverty, and underdevelopment should be undertaken in those areas where zoonoses are most prevalent. Disciplines, such as Ecology, Epidemiology, Medical Entomology, Human and Veterinary Medicine, Environmental Studies, Public Health, Social and Political Studies, Immunology, Microbiology, and Pharmacology could all provide important contributions that aim to reduce the occurrence of factors governing the spread of
[Imposex in Voluta musica (Caenogastropoda: Volutidae) from Northeastern Peninsula de Araya, Venezuela].
Peralta, Ana Carolina; Miloslavich, Patricia; Bigatti, Gregorio
Voluta musica is a dioecious marine gastropod endemic of the South Caribbean. Tributyltin (TBT) and copper (Cu) are potential inducers of imposex, an endocrine disorder by which females develop a penis and/or vas deferens. The goal of this work was to determine the imposex incidence in V. musica populations from Northeastern Peninsula de Araya. For this, we selected three sites (Isla Caribe, Isla Lobos and Bajo Cuspe) and made monthly samplings of 15 snails in each site, during one year, and determined: (1) sizes; (2) sex and imposex incidence and (3) the Relative Penis Length Index (RPLI). We also performed histological analysis of the gonads, and measured TBT and Cu concentrations in sediments from the studied localities. Our results showed that the total number of sampled females affected by imposex was 24.5% at Isla Caribe, 12% at Isla Lobos, and none at Bajo Cuspe. In sediments, Cu was detected mostly in Isla Lobos. The female gonads with imposex did not show any development of male cells in any of the sampled sites. The higher percentage of females with imposex matched with the higher boat traffic locality, and higher TBT level (Isla Caribe). No esterilization was evident in this work, nevertheless, the presence of TBT and Cu in the sediments and females with imposex were considered as a potential threat to V. musica populations in this region. In Venezuela there is no control over this particular issue, possibly because of the lack of information and research in this topic, but certainly, this information will be useful in biodiversity conservation policies. PMID:25102636
Spectral analysis of gravity anomalies and the architecture of tectonic wedging, NE Venezuela and Trinidad
NASA Astrophysics Data System (ADS)
Russo, R. M.; Speed, R. C.
We have analyzed the spectral content of free air gravity anomalies in the Caribbean-South American plate boundary zone in order to determine better the near-surface (0-120 km) distribution of crustal and upper mantle elements which give rise to the unusual gravity field of this region. The plate boundary zone in northeastern Venezuela and Trinidad is the site of the world's sea level continental minimum of Bouguer gravity anomalies, yet the region is also one of mild topography (mean value 43 m, maximum 1200 m). We find the mean depths to interfaces of significant density contrast at a variety of depths for portions of the plate boundary zone. We interpret interfaces at 30-35 km and 32 km beneath the Guyana Shield and the Aves Ridge, respectively, to be the Moho. Other shallow interfaces (5-14 km) are most likely sediment cover-basement contacts in the Maturin foreland basin and southern Grenada Basin. Deeper interfaces (54-63 km) we associate with loaded and downwarped continental and oceanic South American lithosphere. The deepest boundaries, at depths of 89-120 km, may be related to detached or detaching oceanic lithosphere overridden by continental South America. We use our results to test the tectonic wedging model of the plate boundary zone recently published by Russo and Speed (1992). We find that the tectonic wedging model adequately describes many of the structural boundaries inferable from our analysis of gravity anomalies but that the model must be modified to include a thinner Guyana Shield crust.
Reduced susceptibility to quinolones among Salmonella serotypes isolated from poultry at slaughter in Venezuela.
Boscán-Duque, Leonardo A; Arzálluz-Fisher, Ana M; Ugarte, Carmen; Sánchez, Damarys; Wittum, Thomas E; Hoet, Armando E
Today there are recognized global "hot spots" that are areas in which nontyphoid Salmonella serotypes have been reported to have a high prevalence of quinolone resistance. There is concern that resistant strains can be disseminated from these localized geographical areas by travelers or via commercial food products. The objective of this article is to report a high frequency of reduced susceptibility to first- and second-generation quinolones among nontyphoid Salmonella isolates from poultry at slaughter in two processing plants belonging to the largest poultry integration companies in Zulia State, Venezuela. Nearly all (74 of 77; 96.1%) of the isolated strains were resistant to nalidixic acid, and 3.7% were resistant to ciprofloxacin; most (45 of 77; 58%) exhibited reduced susceptibility to ciprofloxacin and norfloxacin (15 of 77; 19.5%). In contrast, all of the isolates were susceptible to beta-lactamic antimicrobial drugs. Ninety-three percent (72 of 77) of the isolates were either Salmonella Parathyphi B or Salmonella Heidelberg, which have been reported as invasive Salmonella. The predominant serotypes in each slaughter plant showed different antimicrobial susceptibilities, only having in common their high resistance to nalidixic acid, suggesting that different clones disseminated in each commercial integration. The detection of high frequency of reduced susceptibility to first- and second-generation quinolones among nontyphoid Salmonella isolates from fresh poultry during processing is noteworthy. Resistance to quinolone drugs will not only make antimicrobial therapy more complicated if foodborne disease results, but also these quinolone-resistant strains can disseminate from this local hot spot to other geographical areas, spreading the resistance against this important antimicrobial drug. PMID:17900079
Mechanisms of Oryza sativa (Poaceae) resistance to Tagosodes orizicolus (Homoptera: Delphacidae) under greenhouse condition in Venezuela.
González, Alex; Labrín, Natalia; Alvarez, Rosa M; Jayaro, Yorman; Gamboa, Carlos; Reyes, Edicta; Barrientos, Venancio
Tagosodes orizicolus is one of the main plagues of rice in tropical America causing two types of damages, the direct one, feeding and oviposition effect, and an indirect one, by the transmission of the "Rice hoja blanca virus". During 2006-2007 we carried out research under greenhouse conditions at Fundaci6n Danac, Venezuela, in order to determine the mechanisms of antixenosis, antibiosis and tolerance to T. orizicolus, which could be acting in commercial varieties and advanced lines of the rice genetic breeding programs of INIA and Fundaci6n Danac. The method of free feeding was used for the antixenosis evaluation, whereas the method of forced feeding was used for antibiosis evaluation (effect on survival and oviposition). Additionally, we used the indirect method based on biomass depression to estimate the tolerance. Some of the evaluated traits included: grade of damage, number of insects settling on rice plants, percentage of sogata mortality at the mature state, number of eggs in the leaf midrib and an index of tolerance. The results showed that rice genotypes possess different combinations of resistance mechanisms, as well as different grades of reactions. The susceptible control 'Bluebonnet 50' was consistently susceptible across experiments and the resistant control 'Makalioka' had high antixenosis and high antibiosis based on survival and oviposition. The rest of the genotypes presented lower or higher degrees of antixenosis and antibiosis for survival and oviposition. The genotype 'FD0241-M-17-6-1-1-1-1' was identified with possible tolerance to the direct damage of sogata. PMID:22458212
Massive bleaching of coral reefs induced by the 2010 ENSO, Puerto Cabello, Venezuela.
del Mónaco, Carlos; Haiek, Gerard; Narciso, Samuel; Galindo, Miguel
El Niño Southern Oscillation (ENSO) has generated global coral massive bleaching. The aim of this work was to evaluate the massive bleaching of coral reefs in Puerto Cabello, Venezuela derived from ENSO 2010. We evaluated the bleaching of reefs at five localities both at three and five meter depth. The coral cover and densities of colonies were estimated. We recorded living coral cover, number and diameter of bleached and non-bleached colonies of each coral species. The colonies were classified according to the proportion of bleached area. Satellite images (Modis Scar) were analyzed for chlorophyll-a concentration and temperature in August, September, October and November from 2008-2010. Precipitation, wind speed and air temperature information was evaluated in meteorological data for 2009 and 2010. A total of 58.3% of colonies, belonging to 11 hexacoral species, were affected and the greatest responses were observed in Colpophyllia natans, Montastraea annularis and Montastraeafaveolata. The most affected localities were closer to the mainland and had a bleached proportion up to 62.73+/-36.55%, with the highest proportion of affected colonies, whereas the farthest locality showed 20.25+/-14.00% bleached and the smallest proportion. The salinity in situ varied between 30 and 33ppm and high levels of turbidity were observed. According to the satellite images, in 2010 the surface water temperature reached 31 degree C in August, September and October, and resulted higher than those registered in 2008 and 2009. Regionally, chlorophyll values were higher in 2010 than in 2008 and 2009. The meteorological data indicated that precipitation in November 2010 was three times higher than in November 2009. Massive coral bleaching occurred due to a three month period of high temperatures followed by one month of intense ENSO-associated precipitation. However, this latter factor was likely the trigger because of the bleaching gradient observed. PMID:23894926
The role of seismic microzoning within the disaster prevention in Venezuela
NASA Astrophysics Data System (ADS)
Malave, G.
Due to the experience of the strong rainfalls which experienced great parts of Venezuela in early 2005, a national commission for risk management (CNGR) was created, that is composed by representatives from the Ministry of Interior and Justice, the Ministry of Environment, Defense Ministry, Infrastructure Ministry, Habitát and Housing Ministry and Science and Tecnology Ministry. The participation of the different ministries, which are represented by institutions related to hidrometeorological research and slope stability, amongst others, enables to focuss the risk management from anintegrated point of view. Within this commission, FUNVISIS, the official agency for seismological investigations, represents the Science and Tecnology Ministry and is responsible for the actions to be taken to reduce the seismic risk. A plan to reduce the seismic hazard and vulnerability, presented by FUNVISIS, was approved by the commission, in order to establish state policies to minimize the impact to the comunities in case of the ocurrence of an earthquake. Therein, seismic microzoning studies are addressed as the methodology to follow in order to reduce the seismic risk, which includes the evaluation of regional conditions (fault ocurrences, source characteristics, attenuation) as well as the knowledge of the local conditions (wave propagation, geological conditions, site effects). The interdisciplinary methods used within the microzoning studies (joint work done by geologists, geophysicists, civil engineers, arquitects, teachers) enable to address the results of the studies in away that they can be assimilated by the communities that live in the respective urban areas as well as by the local governments. Recommendations to local buiding codes as well as training of the communities take an important part within the projects.
3D Spectral Element Method Simulations Of The Seismic Response of Caracas (Venezuela) Basin
NASA Astrophysics Data System (ADS)
Delavaud, E.; Vilotte, J.; Festa, G.; Cupillard, P.
We present here 3D numerical simulations of the response of the Caracas (Venezuela) valley up to 5 Hz for different scenarios of plane wave excitation based on the regional seismicity. Attention is focused on the effects of the 3D basin geometry and of the adjacent regional topography. The simulations are performed using Spectral Element method (SEM) together with an unstructured hexahedral mesh discretization and perfectly matched layers (PML). These simulations show 3D amplification phenomena associated with complex wave reflexion, diffraction and focalisation patterns linked to the geometry of the basin. Time and frequency analysis reveal some interesting features both in terms of amplification and energy residence in the basin. The low frequency amplification pattern is mainly controlled by the early response of the basin to the incident plane wave while the high frequency amplification patterns result mainly from late arrivals where complex 3D wave diffraction phenomena are dominating and the memory of the initial excitation is lost. Interestingly enough, it is shown that H/V method correctly predict the low frequency amplification pattern when apply to the late part of the recorded seismograms. The complex high frequency amplification pattern is shown to be associated with surface wave generation at, and propagation from, sharp edges of the basin. Importance of 3D phenomena is assessed by comparison with simple 2D simulations. Significant differences in terms of time of residence, energy and amplification levels point out the interest of complete 3D modeling. In conclusions some of the limitations associated with the use of unstructured hexahedral meshes will be adressed. Despite the use of unstructured meshing tool, modeling the geometry of geological basins remain a complex and time consuming task. Possible extensions using more elaborate techniques like non conforming domain decomposition will be also discussed in conclusion.
[Bats (Chiroptera: Mammalia) from Yurubí National Park, Venezuela: taxonomic list and community study].
Delgado-Jaramillo, Mariana; Machado, Marjorie; García, Franger J; Ochoa, José
Bats represent a key component in the dynamics of many terrestrial ecosystems, and one of the groups of mammals with the highest levels of diversification in the Neotropics. Here we describe the results of a study of the bat fauna from Yurubí National Park (mountain area in Northern Venezuela), that includes a taxonomic list and the characterization of some community attributes in forested areas. Data was collected from zoological collections and diversified sampling methods from February to July of 2009 in an altitudinal gradient (100-1 500m), with three principal ecological units: semideciduous, evergreen and cloud forests. We recorded 64 species grouped in five families (63% of the bats known from La Cordillera de la Costa), of which Phyllostomidae was the dominant taxa (42 species; 66% of total), followed by Vespertilionidae, Molossidae, Emballonuridae and Mormoopidae. The community with the highest taxonomic diversification was found in the lowest elevation range, while the lowest number of species was found at the highest range. Eleven trophic guilds were identified; the insectivorous guild was the richest, whereas the frugivorous was the most abundant. Our results allow us to indicate these forest ecosystems have an appropriate conservation status, taking into account the presence of a relatively high proportion of species from the subfamily Phyllostominae, as well as the presence of other species with conservation priorities. All these aspects, and the fact that this represents a reservoir of the biological diversity of the forest ecosystems of La Cordillera de la Costa, make this protected area of an essential conservation value, in a highly endangered bioregion by neighboring socio-economic growth. PMID:22208091
Geodetic exploration of strain along the El Pilar Fault in northeastern Venezuela
NASA Astrophysics Data System (ADS)
Reinoza, C.; Jouanne, F.; Audemard, F. A.; Schmitz, M.; Beck, C.
We use Global Navigation Satellite Systems observations in northeastern Venezuela to constrain the El Pilar Fault (EPF) kinematics and to explore the effects of the variable elastic properties of the surrounding medium and of the fault geometry on inferred slip rates and locking depth. The velocity field exhibits an asymmetric velocity gradient on either side of the EPF. We use five different approaches to explore possible models to explain this asymmetry. First, we infer a 1.6 km locking depth using a classic elastic half-space dislocation model. Second, we infer a 1.5 km locking depth and a 0.33 asymmetry coefficient using a heterogeneous asymmetric model, including contrasting material properties on either side of a vertical fault, suggesting that the igneous-metamorphic terranes on the northern side are ~2 times more rigid than the sedimentary southern side. Third, we use a three-dimensional elastostatic model to evaluate the presence of a compliant zone, suggesting a 30% reduction of rigidity in the upper 3 km at the depth of a 1 to 5 km wide fault zone. Fourth, we evaluate the distribution of fault slip, revealing a widespread partial creep pattern in the eastern upper segment, while the upper western segment exhibits a partially locked area, which coincides with the rupture surface of the 1797 and 1929 earthquakes. To supplement these models, we upgrade the previously published displacement simulation method using nonvertical dislocations with data acquired between 2003 and 2013. The localized aseismic displacement pattern associated with creeping or partially creeping fault segments could explain the low level of historic seismicity.
Dynamic controls on accretion and lithification of modern gypsum-dominated thrombolites, Los Roques, Venezuela
NASA Astrophysics Data System (ADS)
Petrash, Daniel A.; Gingras, Murray K.; Lalonde, Stefan V.; Orange, François; Pecoits, Ernesto; Konhauser, Kurt O.
Meter-sized thrombolites coated by well developed zonally differentiated microbial mats have been found growing in the shallow waters (depth < 1 m) of a restricted hypersaline lagoon on the Archipelago Los Roques in Venezuela. By contrast, within the deeper parts of the studied lagoon, sedimentation is characterized by several decimeters of organic-rich material containing gypsum granules lacking carbonate cementation. The lithification of the thrombolites is thought to have proceeded as follows. First, extracellular polymeric substances (EPS) comprising the microbial mat concentrate Ca2 + and other metal cations by adsorption from the hypersaline waters. Second, some of these bound metals then serve as nucleation sites for primary calcium carbonate (CaCO3) precipitation. Third, while carbonate phases are forming in some zones of the mat, in others zones they are being re-dissolved due to the acidity generated through the metabolism of sulfide-oxidizing bacteria, Fourth, as the dissolved sulfide is oxidized into sulfate, the pore-water become saturated with respect to gypsum (CaSO4·2H2O). Fifth, as primary gypsum precipitates within the structures, endolithic sulfate-reducing bacteria metabolize the sulfate moiety in the mineral phase, while simultaneously oxidizing the EPS trapped during accretion. Sixth, as microbial EPS degradation proceeds, the anaerobic oxidation of specific protein fractions of the EPS matrix leads to increased alkalinity, the partial dissolution of gypsum, supersaturation with respect to calcium carbonate, and ultimately pseudomorphic aragonite replacement; this differs from secondary calcite cements in being enriched in 12C, and depleted in minor and trace metals initially associated with the EPS. The biogeochemical processes occurring in this thrombolite-constructing lagoon represent a novel field site for studying the chemical and isotopic processes characterizing early diagenetic gypsum and the role microbes play in its precipitation
High resolution paleoclimatic reconstruction of the last deglaciation in the intertropical Cariaco basin (Venezuela)
NASA Astrophysics Data System (ADS)
Aycard, M.; Bout-Roumazeilles, V.; Tribovillard, N.; Baudin, F.
The aim of this study is a high-resolution reconstruction of the paleoclimate record of the last 16 ka of the Cariaco Basin, using a combination of geochemical and grain-size analyses. The studied core was collected at the ODP site 1002 on the western edge of the central saddle of the basin (off Venezuela). An age model was determined using a correlation between the magnetic susceptibility record and the planktonic foraminifera δ18O record by Peterson et al. (2000) and a 14C AMS dating. Organic carbon, and carbonate contents and grain-size records show a strong correlation with the δ18O record of the Greenland ice cores (GISP) suggesting that the rapid climatic oscillations of the last deglaciation are simultaneous in the inter-tropical zone and the Northern Hemisphere. In fact, a rapid increase in organic carbon content in marine sediments dated approximately 15 ka could be directly connected with melt-water pulse IA. The relative sea-level rise increased the communication between the Cariaco Basin and the open sea with a strong upwelling enhancing the nutrients supply. The end of the Pleistocene is marked by rapid variation of the organic carbon content in relation with cold events. It seems that in the Cariaco Basin that is directly under the influence of the intertropical convergence, there has been an excellent connection between the Northern Hemisphere and the tropics during the last deglaciation. In contrast, it is noteworthy that the 8.2 ka events is not recorded in this area probably because the connection was not complete with a diversion of meltwater from the Mississippi to the Saint Lawrence drainage system during the Younger Dryas. Peterson L.C., et al. (2000) Proceedings of the ODP, Sci. Res., 165, 85-99.
The evaluation of a dipstick test for Plasmodium falciparum in mining areas of Venezuela.
Caraballo, A; Ache, A
A field trial comparing a dipstick test, an antigen-capture test detecting trophozoite-derived histidine-rich protein-II, and the quantitative buffer coat (QBC) (acridine orange staining technique) assay for the detection of Plasmodium falciparum was carried out on a population of 1,398 suspected malaria patients in gold mining areas of Venezuela. Sensitivity, specificity, and positive predictive values were higher for the dipstick test than for the acridine orange staining compared with the thick blood smear. The sensitivity for the dipstick method was 86.7% (95% confidence interval [CI] = 82-90%), the specificity was 99.3% (95% CI = 98.5-99.7%), and the positive predictive value was 97.1% (95% CI = 94-98%) as compared with the thick blood smear. The sensitivity for acridine orange staining was 82.2% (95% CI = 77-86%), the specificity was 98.5% (95% CI = 97.6-99.1%), and the positive predictive value was 94.1% (95% CI = 90-97%); with a P. falciparum asexual parasitemia higher than 21 parasites/microliter, the dipstick was 100% sensitive, when parasitemia was 10-20/microliter, sensitivity was 88%, and when parasitemia was less than 10/microliter, it was only 13.4%. The dipstick assay meets the criteria for an appropriate, rapid, and reliable test for the diagnosis of P. falciparum and has advantages over the acridine orange staining method. Nonetheless, its effectiveness seems limited in areas with low prevalence and among patients with low levels of parasitemia. PMID:8940977
Bearded saki feeding strategies on an island in Lago Guri, Venezuela.
Norconk, Marilyn A; Conklin-Brittain, Nancy L
Free-ranging bearded sakis (Chiropotes spp.) live in relatively large social groups (22-65+), inhabit very large home ranges (200-1,000 ha), and travel long distances (1.8 to >7 km) each day. While these characteristics would seem to reduce their ability to occupy habitat fragments, several studies suggest otherwise. The key to their success may lie in their dietary adaptations. Bearded sakis are strongly frugivorous, but are primarily seed eaters, and are able to ingest both young and mature fruit. We examined feeding activities of a group of bearded sakis over a 19-month period on a 180 ha island in Lago Guri, Venezuela. Given their feeding adaptations, we predicted that they would minimize peaks and troughs in plant species used for food, limit seasonal variation in the mechanical properties of foods ingested, and balance ingestion of energy-rich foods (e.g. lipids, nonstructural carbohydrates (TNC), and/or free simple sugars). We found that bearded sakis on Danto Manchado had a diverse (plant-based) diet, but two resources (Pradosia caracasana, Sapotaceae, and Oryctanthus alveolatus, Loranthaceae) provided a stable dietary base and were present in the diet almost every month. Second, we found little variation in the mechanical-resistance properties of fruits opened seasonally. Third, they alternated months ingesting foods with high TNC content and months of high lipid content. This may be an attempt to balance energy intake from available foods. Finally, their social propensity to split up into subgroups may predispose them to reduce group sizes to accommodate smaller available areas. We suggest that bearded sakis use both ecological and behavioral mechanisms to survive in smaller-than-typical areas. Longer-term studies (beyond a few generations) of bearded sakis in habitat fragments would allow us to estimate minimum survival area and identify critical resources or resource combinations. Am. J. Primatol. 78:507-522, 2016. © 2015 Wiley Periodicals, Inc
Population trends and survival of nesting green sea turtles Chelonia mydas on Aves Island, Venezuela
Garcia-Cruz, Marco A.; Lampo, Margarita; Penaloza, Claudia L.; Kendall, William; Solé, Genaro; Rodriguez-Clark, Kathryn M.
Long-term demographic data are valuable for assessing the effect of anthropogenic impacts on endangered species and evaluating recovery programs. Using a 2-state open robust design model, we analyzed mark-recapture data from green turtles Chelonia mydas sighted between 1979 and 2009 on Aves Island, Venezuela, a rookery heavily impacted by human activities before it was declared a wildlife refuge in 1972. Based on the encounter histories of 7689 nesting females, we estimated the abundance, annual survival, and remigration intervals for this population. Female survival varied from 0.14-0.91, with a mean of 0.79, which is low compared to survival of other populations from the Caribbean (mean = 0.84) and Australia (mean = 0.95), even though we partially corrected for tag loss, which is known to negatively bias survival estimates. This supports prior suggestions that Caribbean populations in general, and the Aves Island population in particular, may be more strongly impacted than populations elsewhere. It is likely that nesters from this rookery are extracted while foraging in remote feeding grounds where hunting still occurs. Despite its relatively low survival, the nesting population at Aves Island increased during the past 30 years from approx. 500 to >1000 nesting females in 2009. Thus, this population, like others in the Caribbean and the Atlantic, seems to be slowly recovering following protective management. Although these findings support the importance of long-term conservation programs aimed at protecting nesting grounds, they also highlight the need to extend management actions to foraging grounds where human activities may still impact green turtle populations.
Chagas' Disease: An Emergent Urban Zoonosis. The Caracas Valley (Venezuela) as an Epidemiological Model
Urdaneta-Morales, Servio
The unprecedented emergence of important public health and veterinary zoonoses is usually a result of exponential population growth and globalization of human activities. I characterized Chagas' disease as an emergent zoonosis in the Caracas Valley (Venezuela) due to the following findings: the presence of reservoirs (Didelphis marsupialis, Rattus rattus) and vectors (Panstrongylus geniculatus, Panstrongylus rufotuberculatus) infected with Trypanosoma cruzi in urbanized or marginalized areas; the elevated contact between P. geniculatus and human beings detected by parasitological and molecular examinations of triatomine feces demonstrated the possibility of transmission risks; a study of outbreaks of urban Chagas' disease reported the first proven case of oral transmission of T. cruzi to human beings; the risk of transmission of glandular metacyclic stages from marsupials by experimental ocular and oral instillation; mice genitalia infected with T. cruzi contaminated blood resulted in the formation of amastigotes very close to the lumen suggesting that there may be a possibility of infection via their release into the urine and thence to the exterior; the ubiquitous histotropism and histopathology of T. cruzi was demonstrated using a mouse model; the presence of experimental T. cruzi pseudocysts in adipose, bone-cartilage, and eye tissue indicated a potential risk for transplants. Socio-sanitary programs that include improvements in housing, vector control, and access to medical treatment, as well as strategies aimed at combating social inequalities, poverty, and underdevelopment should be undertaken in those areas where zoonoses are most prevalent. Disciplines, such as Ecology, Epidemiology, Medical Entomology, Human and Veterinary Medicine, Environmental Studies, Public Health, Social and Political Studies, Immunology, Microbiology, and Pharmacology could all provide important contributions that aim to reduce the occurrence of factors governing the spread of
Sedimentary and tectonic controls on oil occurrences in the traditional producing area, Barinas Subbasin, Western Venezuela
Daal, J.; Martinez, G.; Salas, J.
A Stratigraphic and Tectonic model explains the oil-field locations in the Traditional Producing Area of the Barinas Subbasin, Western Venezuela. The database for the model includes a 585-km{sup 2} 3-D seismic survey, as well as petrophysical, lithologic and biostratigraphic data from Cretaceous and Tertiary sediments. A long-term relative sea level rise from Albian through Campanian (Cretaceous) time, coincident with passive-margin basin subsidence, resulted in onlap of marginal marine sands and marine-shelf limestones and shales over crystalline metamorphic rocks of the Guayana Shield Basement. Facies changes in the Cretaceous Aguardiente, Escandalosa, and Navay Formations are related mainly to eustatic sea level changes. A tectonic pulse deformed these sediments in Late Maastrichtian to Paleocene time. An erosional unconformity that developed atop this deformed Cretaceous section relates to tectonic uplift and not to sea-level change. Onlap of Middle Eocene marine transgressive Gobernador Fm. sands and Masparrito Fm. limestones over this unconformity was driven by increased tectonic subsidence. Accelerated tectonic subsidence drowned the Masparrito carbonate platform and led to deposition of a condensed section within the lower Paguey Formation; this condensed section marks a tectonic Maximum Flooding Surface not related to eustatic sea level change. After deposition of the Eocene Paguey, and just prior to deposition of the Oligo-Miocene Parangula Formation, a second tectonic event reactivated older faults and led to growth of structural traps for Cretaceous and Eocene reservoirs. Both tectonic and eustatic events have combined to control oil occurrence in the Barinas Subbasin.
Chronostratigraphy of the Cretaceous-Oligocene unconformity in Northern Monagas, Eastern Venezuela
Helenes, J. )
Palynological analyses of several subsurface sections in the autochthonous block in Northern Monagas, eastern Venezuela, show a Cretaceous-Oligocene unconformity. The Maastrichtian to Paleocene sandstones of the San Juan Formation unconformably underlie the Oligocene to Miocene sandstones of the Merecure Formation. Log analyses indicate two stratigraphic sequences within San Juan and two more within Merecure, and integration with paleontological data indicates changes which can be correlated with Haq et al.'s (1988) Sequence Chronostratigraphic Charts as follows: (1) The basal San Juan sandstones represent the late Maastrichtian (68 Ma) drop of seal level and the UZA-4.5/TA-1.1 Sequence Boundary (SB). The Maastrichtian or Maastrichtian to Paleocene San Juan sandstones represent either the TA-1.1 and the TA-1.2 Third-Order Cycles. (2) The late Oligocene sequence overlying the unconformity, represents the TB-1.3 Cycle starting at 26.5 Ma. Within this lower part of the Merecure sediments, an increase in the abundance and diversity of marine palynomorphs represents a maximum transgression correlatable with the 26 Ma Condensed Section contained in the Tb-1.3 Cycle. (3) The upper part of Merecure represents the Tb-1.4 Cycle starting at 25.5 Ma. Within this cycle, the lowermost (Oligocene) sandstones contain almost exclusively terrestrial palynomorphs, while the (Miocene) alternating sands and shales of the upper part contain diverse marine palynomorphs indicating a change from Low Stand Wedge to Transgressive deposits. This change is correlated with the Oligocene/Miocene limit at 25.2 Ma.
Asymmetrical and heterogeneous elasto-static deformation along the El Pilar Fault in Northeastern Venezuela
NASA Astrophysics Data System (ADS)
Reinoza, C.; Jouanne, F.; Audemard, F. A.; Beck, C.
Velocities field in both sides of the El Pilar fault, the most important right-lateral strike-slip fault of the Caribbean-South America plate boundary, present an important asymmetry. This pattern suggests a change in elastic properties when crossing the fault. We have applied an asymmetric model to simulate observed velocities with 20 mm/yr creep at depth, corresponding at the relative velocity of Caribbean plate versus South America plate. The preferred model indicated a shallow locking depth at 4.5 km. In a second part, a near-fault low-rigidity compliant zone from 3 km of depth with a 30 per cent of rigidity reduction respect to the environment is proposed using a 3D elasto-static model. We use GPS data from 23 stations collected in 2002 and 2005 like input parameters as well as geometry parameters based in previous work. The shallow locking depth and the interseismic velocities used in the asymmetry and compliant zone models respectively support: i) the hypothesis of a partially locked seismogenic upper part, ii) the concentration of the Caribbean- South America relative displacement entirely along the El Pilar Fault. Reinoza Carlos PhD thesis and stay in ISTerre Laboratory is funded through Venezuela's FUNDAYACUCHO Grant N° 756514C. This research is a contribution to FONACIT-ECOS Nord grant 2009000818 (French code V10U01). Observed velocities (white) from 2002 and 2005 GPS campaign measurements data with error ellipses drawn for 66% confidence level expressed in the South America plate reference frame.
Misoa formation sandstone diagenesis, blocks III and V, Maracaibo Basin, Venezuela
Manske, C.M. )
The petroliferous Lower-Middle Eocene Misoa Formation of the central Maracaibo Basin, Venezuela, is considered an ideal rock unit for investigation of controls on reservoir diagenesis. The Misoa Formation of the central Basin is typically a fine to medium grained, moderately to well sorted sandstone, with shale interbeds, representing deposition in various delta front to shallow marine environments. Sandstones are mainly sublitharenites and quartzarenites. The diagenetic evolution of the Misoa Formation in Blocks III and V of the central Basin area has been established through quantitative basin modeling, and detailed petrographic analysis involving thin section study, scanning electron microscopy, and X-ray diffraction analysis. The reservoir sandstones have been substantially modified by diagenesis. Porosity enhancement has been created in these rocks through the dissolution of unstable framework grains and carbonate cements. A major control on dissolution may be organic acid flushing prior to hydrocarbon generation; a mechanism supported by quantitative basin modeling results. A second control on porosity enhancement and reservoir quality is extensive leaching by meteoric waters near the post-Eocene unconformity surface. Sandstones nearer this surface have excellent porosity and permeability, and display profuse leaching of grains, clays, carbonate cements, and even quartz. Although Misoa sediments were affected by basin-wide tectonism including initial Eocene subsidence, an extended period of post-Eocene uplift and erosion and Miocene subsidence, the paragenetic sequence appears uniform. This diagenetic scenario reflects early burial diagenesis, telediagenesis, and medium to late burial diagenesis stages. Authigenic minerals include various carbonate, silica, and clay phases. The clay mineral assemblage in this area is represented by common kaolinite, with subordinate discrete illite, and ordered mixed-layer and expandable mixed-layer illite/smectite, chlorite.
Impact of freshwater diagenesis on reservoir quality: B-6 sands, Mosoa Formation, Venezuela
Ghosh, S.K.; Di Croce, J.; Isea, A.
Various northwest-southeast-trending fault-bounded Eocene reservoirs in the Maracaibo basin exhibit a systematic trend of diagenetic evolution as a response to changing chemical and physical conditions related to two phases of subsidence (Eocene and Miocene) separated by a period of major Oligocene uplift. The initial subsidence, more important than that of the Miocene, caused compaction, cementation, and dissolution, reducing original porosity from 40% to about 20%. The Oligocene regional uplift created abundant secondary porosity, specifically in the vicinity of the truncated erosion surface at the northwest limit of the reservoirs, through intensive meteoric leaching of framework grains and cements by undersaturated CO/sub 2/-charged waters. Both the porosity and permeability systematically decrease southeastward as the vertical distance from the unconformity surface increases. The sands immediately below the erosional unconformity have the best reservoir quality. They show profuse leaching of monocrystalline and polycrystalline quartz and are virtually free of unstable rock fragments, feldspar, and authigenic clays. In contrast, labile grains largely persist in the areas away from the unconformity where cements of calcite and clays have moderately reduced the reservoir quality. Some of the dissolved silica, resulting from quartz and feldspar dissolution near the unconformity surface, would have precipitated in the areas to the southeast where a patchily welded texture commonly was observed. Similar processes of silica dissolution through meteoric water leaching occur in outcrops of Precambrian karstic quartzarenites in Venezuela. These modern analogs in areas of heavy rainfall and copious production of inorganic and organic acids corroborate the efficacy of a freshwater flushing mechanism and consequent enhancement of reservoir quality in the Eocene sequence.
Politics, class actors, and health sector reform in Brazil and Venezuela.
Mahmood, Qamar; Muntaner, Carles
Universal access to healthcare has assumed renewed importance in global health discourse, along with a focus on strengthening health systems. These developments are taking place in the backdrop of concerted efforts to advocate moving away from vertical, disease-based approaches to tackling health problems. While this approach to addressing public health problems is a step in the right direction, there is still insufficient emphasis on understanding the socio-political context of health systems. Reforms to strengthen health systems and achieve universal access to healthcare should be cognizant of the importance of the socio-political context, especially state-society relations. That context determines the nature and trajectory of reforms promoting universality or any pro-equity change. Brazil and Venezuela in recent years have made progress in developing healthcare systems that aim to achieve universal access. These achievements are noteworthy given that, historically, both countries had a long tradition of healthcare systems which were highly privatized and geared towards access to healthcare for a small segment of the population while the majority was excluded. These achievements are also remarkable since they took place in an era of neoliberalism when many states, even those with universally-based healthcare systems, were moving in the opposite direction. We analyze the socio-political context in each of these countries and look specifically at how the changing state-society relations resulted in health being constitutionally recognized as a social right. We describe the challenges that each faced in developing and implementing healthcare systems embracing universality. Our contention is that achieving the principle of universality in healthcare systems is less of a technical matter and more a political project. It involves opposition from the socially conservative elements in the society. Navigation to achieve this goal requires a political strategy that
PREFACE: XII Latin American workshop on plasma physics (17-21 September 2007, Caracas, Venezuela)
NASA Astrophysics Data System (ADS)
Puerta, Julio
Some years ago a group of Latin American physicists took the initiative to consult about the viability of organizing a meeting on plasma physics for researchers and students of the region. The result was that it was not only a good idea, but a necessity in order to show and share everyone's work, and to keep updated on latest advances and technologies on plasma physics. It was decided that for new researchers as well as students of Physics, it would prove to be the best way to keep them posted on such matters. This was the birth of a series of meetings known as Latin American workshops on plasma physics that take place every two years in a different Latin American country. In Venezuela we have had the opportunity to organize two editions of this interesting and important reunion of physicists. The first of these Latin American workshops on plasma physics was held in Cambuquira (Brazil) in 1982. After organizing the first six editions of the workshop, the VII LAWPP meeting was realized in Caracas in January 1997. It was designed with a structure similar to the first edition. It developed in two stages, a first week devoted to short courses with lecturers in different fields of plasma physics and a second week for contributed and invited presentations. Participants from sixteen different countries were present, half of them from this continent and the other half from overseas, demonstrating the international character of this meeting. There have been four more editions of the workshop and once again, we have had the opportunity to organize this latest edition of the series: the XII Latin American workshop on plasma physics, which took place in Caracas, Venezuela from the 17th to the 21st of September 2007. The structure was modified, because contributed and review papers were together during the first stage, with short courses realized during the second one, called mini-courses, and given by several high level contributors such as José Boedo, Leopoldo Soto, Claude
The preliminary results of the measurements of environmental levels of 40K and 137Cs in Venezuela
NASA Astrophysics Data System (ADS)
LaBrecque, J. J.; Rosales, P. A.; Carias, O.
The study of the beta-particle radioactivity in air and 90Sr in rainwater collected at Instituto Venezolano de Investigaciones Cientificas, IVIC, that began in 1959 in conjunction with the U.S. Atomic Energy Commission was discontinued in 1963. But after the Chernobyl nuclear power plant accident in the USSR, work on the radioactive contamination in Venezuela has been renewed. Initially the measurement of 134Cs and 137Cs in imported foodstuffs, such as milk powders and meats were undertaken, and these have now been extended to measurements of environmental levels of 40K and 137Cs in soils, sea sediments and foodstuffs. The data present herein are the only readily available data on radioactive contamination in the environment in Venezuela since 1963. The measurements were performed with a simple Nal(Tl) detector and two single channel analyzers as well as with a 25% efficient hyper-pure germanium semiconductor coupled to a multichannel analyzer system. Finally, these results can be used as baseline values (environmental background) in case of a nuclear accident in the region, as well as to screen imported foodstuff which is suspected to be contaminated.
Development, Antibiotic Production, and Ribosome Assembly in Streptomyces venezuelae Are Impacted by RNase J and RNase III Deletion
Jones, Stephanie E.; Leong, Vivian; Ortega, Joaquin
RNA metabolism is a critical but frequently overlooked control element affecting virtually every cellular process in bacteria. RNA processing and degradation is mediated by a suite of ribonucleases having distinct cleavage and substrate specificity. Here, we probe the role of two ribonucleases (RNase III and RNase J) in the emerging model system Streptomyces venezuelae. We show that each enzyme makes a unique contribution to the growth and development of S. venezuelae and further affects the secondary metabolism and antibiotic production of this bacterium. We demonstrate a connection between the action of these ribonucleases and translation, with both enzymes being required for the formation of functional ribosomes. RNase III mutants in particular fail to properly process 23S rRNA, form fewer 70S ribosomes, and show reduced translational processivity. The loss of either RNase III or RNase J additionally led to the appearance of a new ribosomal species (the 100S ribosome dimer) during exponential growth and dramatically sensitized these mutants to a range of antibiotics. PMID:25266378
[Fishery and biology of Rhinobatospercellens (Rajiformes: Rhinobatidae) caught by the artisanal fishery at La Pared beach, Venezuela].
Tagliafico, Alejandro; Rago, Néstor; Rangel, Maria Salomé
R. percellens is incidentally caught in Venezuela by the artisanal fishery using bottom gillnets. This species was classified by the IUCN as being "near threatened", and there is poor knowledge about its biology and fishery in Venezuela. For this reason, we analyzed the specimens caught by the artisanal fleet in playa La Pared, once a week, from January to December 2007. We determined total length, sex and maturity for each captured specimen. A total of 210 specimens were analyzed, 159 females and 51 males. The 81% of all specimens caught were adults, but within this group 27% were pregnant. The average size of sexual maturity was found between 51 and 52cm for females and males, respectively. Adult females were found all year round, and pregnant females in seven of the months sampled; highest numbers were found between February-March and September. The analyzed females had a total of 96 embryos with a size range between 2 and 19cm, with a maximum fertility of four embryos per litter. February and June-July showed the maximum breeding time, and considering the broad range of embryos sizes and the frequency of pregnant females along the different months, allow us to believe that they reproduce throughout the year. Fishing regulation including minimum catch size in relation to maturity length and release of pregnant females in water is recommended. PMID:23894969
[Community structure of bivalves and gastropods in roots of red mangrove Rhizophora mangle (Rhizophoraceae) in isla Larga, Mochima Bay, Venezuela].
Acosta Balbas, Vanessa; Betancourt Tineo, Rafael; Prieto Arcas, Antulio
The Rhizophora mangle roots form a complex ecosystem where a wide range of organisms are permanently established, reproduce, and find refuge. In this study, we assessed the diversity of bivalves and gastropods that inhabit red mangrove roots, in isla Larga, Mochima, Venezuela Sucre state. Bimonthly collections were made from January 2007 to May 2008, in four study areas denominated: South, North, East and West. In each area, five mangrove roots were sampled, and the specimens were obtained. We analyzed a total of 180 roots and a total of 35 bivalve species and 25 gastropod species were found. The most abundant bivalves were: Isognomon alatus, Isognomon bicolor, Ostrea equestris, Crassostrea rhizophorae and Brachidontes exustus; among gastropods, the most common where: Littorina angulifera, (Cymatium pileare and Diodora cayenensis. The months with the highest abundances and number of individuals for both groups were January and July 2007, and March 2008. The mangrove ecosystem in isla Larga, presented a number of individuals and species higher than those reported for other regions in Venezuela and the Caribbean. PMID:25102639
Venezuela-MEM/USA-DOE Fossil Energy Report IV-11: Supporting technology for enhanced oil recovery - EOR thermal processes
This report contains the results of efforts under the six tasks of the Tenth Amendment anti Extension of Annex IV, Enhanced Oil Recovery Thermal Processes of the Venezuela/USA Energy Agreement. This report is presented in sections (for each of the six Tasks) and each section contains one or more reports that were prepared to describe the results of the effort under each of the Tasks. A statement of each Task, taken from the Agreement Between Project Managers, is presented on the first page of each section. The Tasks are numbered 68 through 73. The first through tenth report on research performed under Annex IV Venezuela MEM/USA-DOE Fossil Energy Report Number IV-1, IV-2, IV-3, IV-4, IV-5, IV-6, IV-7, IV-8, IV-9, IV-10 contain the results of the first 67 Tasks. These reports are dated April 1983, August 1984, March 1986, July 1987, November 1988, December 1989, October 1991, February 1993, March 1995, and December 1997, respectively.
Evaluation of GO_CONS_GCF_2_TIM and GOCO01S Geopotential Models in Venezuela and Caribbean Region
NASA Astrophysics Data System (ADS)
Orihuela, N. D.; Garcia, A. D.; Tabare, T.; Scientific Team Of Venezuelan; Caribbean Crustal Study From Satellital Data
This paper shows two maps of the magnitude of the surface gravity vector (MSGV) of Venezuela and Caribbean region at 1:500.000 scale in the geographic window between the 0-20 north latitude and 74-58 western longitude (Fig. 1 and Fig. 2), that were generated from GOCE gravity gradients data provided by the European Space Agency (ESA). The maps that are showed come from the combined global gravity field model GOCO01s [GOCO Consortium., 2010] and from the satellite-only global gravity field model GO_CONS_GCF_2_TIM [Pail et al., 2010], both of 224 degree. The DEMs used for the evaluation of the MSGV are: Etopo2v2 [NGDC., 2006] and Etopo1 [Amante and Eakins, 2009] respectively. The data processing was done using: Shm2func [ICGEM., 2007]; Goce User Toolbox [ESA., 2009]; Gravsoft package [Tscherning et al., 1992] and Oasis Montaj (Geosoft). This research shows a review of observed gravity in the main geological provinces of the Venezuela and Caribbean region geography, revealing gravitational features important of the geological structures that are in Venezuelan and Caribbean subsurface.
Dengue Seroprevalence and Risk Factors for Past and Recent Viral Transmission in Venezuela: A Comprehensive Community-Based Study
Velasco-Salas, Zoraida I.; Sierra, Gloria M.; Guzmán, Diamelis M.; Zambrano, Julio; Vivas, Daniel; Comach, Guillermo; Wilschut, Jan C.; Tami, Adriana
Dengue transmission in Venezuela has become perennial and a major public health problem. The increase in frequency and magnitude of recent epidemics prompted a comprehensive community-based cross-sectional study of 2,014 individuals in high-incidence neighborhoods of Maracay, Venezuela. We found a high seroprevalence (77.4%), with 10% of people experiencing recent infections. Multivariate logistic regression analysis showed that poverty-related socioeconomic factors (place and duration of residence, crowding, household size, and living in a shack) and factors/constraints related to intradomiciliary potential mosquito breeding sites (storing water and used tires) were linked with a greater risk of acquiring a dengue infection. Our results also suggest that transmission occurs mainly at home. The combination of increasingly crowded living conditions, growing population density, precarious homes, and water storage issues caused by enduring problems in public services in Maracay are the most likely factors that determine the permanent dengue transmission and the failure of vector control programs. PMID:25223944
High occurrence of Acanthamoeba genotype T4 in soil sources from Bolívar State, Venezuela.
Wagner, Carolina; Reyes-Batlle, María; Hernán, Aurora; Rojas, Elsy; Pérez, Gladymar; López-Arencibia, Atteneri; Sifaoui, Ines; Martínez-Carretero, Enrique; Piñero, José E; Valladares, Basilio; Lorenzo-Morales, Jacob
Pathogenic strains of Acanthamoeba are causative agents of keratitis and encephalitis that often may end fatal in humans and other animals. In the present study, twenty-seven soil samples were collected in the Bolivar State in Venezuela and checked for the presence of Acanthamoeba. Samples were cultivated onto 2% non-nutrient agar plates seeded with a layer of heat killed E. coli. Amplification by PCR and sequencing of the DF3 region of the 18S rDNA of Acanthamoeba was carried out in order to confirm morphological identification of the amoebae. Furthermore, Acanthamoeba spp. was isolated from 51.8% of soil samples. Sequencing of the DF3 region of the 18S rDNA resulted in the identification of genotype T4 in all samples. To the best of our knowledge, this is the first report of genotype T4 in soil sources from Venezuela. Further studies should be carried out in this State and in the country in order to determine the current occurrence of Acanthamoeba in Venezuelan environments. PMID:27447209
Dengue seroprevalence and risk factors for past and recent viral transmission in Venezuela: a comprehensive community-based study.
Velasco-Salas, Zoraida I; Sierra, Gloria M; Guzmán, Diamelis M; Zambrano, Julio; Vivas, Daniel; Comach, Guillermo; Wilschut, Jan C; Tami, Adriana
Dengue transmission in Venezuela has become perennial and a major public health problem. The increase in frequency and magnitude of recent epidemics prompted a comprehensive community-based cross-sectional study of 2,014 individuals in high-incidence neighborhoods of Maracay, Venezuela. We found a high seroprevalence (77.4%), with 10% of people experiencing recent infections. Multivariate logistic regression analysis showed that poverty-related socioeconomic factors (place and duration of residence, crowding, household size, and living in a shack) and factors/constraints related to intradomiciliary potential mosquito breeding sites (storing water and used tires) were linked with a greater risk of acquiring a dengue infection. Our results also suggest that transmission occurs mainly at home. The combination of increasingly crowded living conditions, growing population density, precarious homes, and water storage issues caused by enduring problems in public services in Maracay are the most likely factors that determine the permanent dengue transmission and the failure of vector control programs. PMID:25223944
Biotechnical performance of vegetal species in slope conservation in Cruz Alta, RS, Brazil
NASA Astrophysics Data System (ADS)
Prates Bisso, Fernando; Durlo, Miguel
The aim of this work was the evaluation of biotechnical performance of different vegetal species growth in the slope soil conservation and reforest (revegetate). The study was performed with oxic soil talus, in Cruz Alta - RS, Brazil (28°23'28.14" S and 53°22'25.61" W) and began in January 2010. The sow treatments employed were: 1) cuttings of Ateleia glazioveana; 2) cuttings of Pyrostegia venusta; 3) seedlings of Baccharis trimera; 4) Seedlings of Cynodom plectostachyus; 5) blank, no sow. The evaluated parameters were: plant survival ratio (%); vegetal covered percentage; natural revegetation (plants/m2); the slope soil level reduction (cm); and water and soil runoff. C. plectostachyus and B. trimera afforded considerable higher survival (92% and 78.5%, respectively) and vegetation cover of the slope (99.6% and 82.9%) than other species. The natural revegetation showed an increase according to the ground above the slope (146.9 plants/m2) compared with the slope ramp (22.1 plants/m2). Moreover, C. plectostachyus, A. glazioveana, P. venusta, B. trimera and C. plectostachyus treatments showed 34.9, 28.6, 23.0 and 21.0 plants/m2, respectively, when compared with the blank (2.5 plants/m2) in the slope ramp region. Furthermore, the sow line regions gave 91.2 plants/m2) whereas the regions among lines afforded 8.6 plants/m2. Additionally, C. plectostachyus showed soil average drawdown profile decrease of 12.8 mm after 360 days after planting, and A. glazioveana reached 16.9 mm after 540 days according to the blank (34.0 mm). Considering the period of 60 to 360 days, it was observed significant differences in the soil loss estimative and reduction percentage compared to blank were: Blank 127.9 ton/ha/year; A. glazioveana, 117.9 ton/ha/year (-8%); P. venusta, 116.3 ton/ha/year (-9%); B. trimera, 106.7 ton/ha/year (-17%); and C. plectostachyus, 73.2 ton/ha/year (-43%). Thus, C. plectostachyus showed the best survival and vegetal coverage producing significant reduction of
Alta FT-150: The Thruster for LISA Pathfinder and LISA/NGO Missions
NASA Astrophysics Data System (ADS)
Paita, L.; Cesari, U.; Nania, F.; Priami, L.; Rossodivita, A.; Giusti, N.; Andrenucci, M.; Estublier, D.
FT-150© FEEP thruster has successfully completed an endurance test at Alta's Micropropulsion laboratory. The updated thruster design dramatically enhances performance with respect to previous FEEP devices and marks a major step forward in the LISA Pathfinder and NGO programmes as well as space propulsion capability in general. The test campaign took place in two parts. Firstly, the new design was tested to validate that the new configuration was compliant with the requirements of the Lisa Pathfinder mission with particular emphasis on the achievement of required total impulse and minimum and maximum thrust levels.The second part of the campaign was aimed at testing a worst-case DFACS profile of the LISA Pathfinder mission using the Elegant Breadboard Power Control Unit (EBB PCU) commanding at 10 Hz and acquiring at 50 Hz. Both purposes of the campaign were successfully met. A total impulse of more than 1080 Ns and a firing time of more than 3500 hours were achieved. No degradation of efficiency and performance was recorded over the entire test. During the first part, more then 600 Ns of total impulse and about 2000 hours of firing time were achieved. Different thrust profiles were commanded with an average thrust of about 87 μN. The minimum and maximum thrust were 1 μN and 150 μN respectively. Short periods at zero N (i.e. thruster switched-off) were also commanded. The measured mass efficiency and specific impulse, 60% and 8000 s respectively, demonstrated that the current design of the thruster is fully compatible with the much larger impulse requirement of LISA mission. The simulation of the worst-case DFACS cycles at 10 Hz was also successfully performed. Three different DFACS cycles representative of the worst cases were performed. These cycles highlighted one of the main advantages of this technology: the controllability and response time that can be verified immediately with electrical feedback parameters like total voltage and beam current (data
Improvement of chloramphenicol production in Streptomyces venezuelae ATCC 10712 by overexpression of the aroB and aroK genes catalysing steps in the shikimate pathway.
Vitayakritsirikul, Vipawan; Jaemsaeng, Ratchaniwan; Lohmaneeratana, Karan; Thanapipatsiri, Anyarat; Daduang, Ratama; Chuawong, Pitak; Thamchaipenet, Arinthip
Streptomyces venezuelae ATCC 10712 produces chloramphenicol in small amounts. To enhance chloramphenicol production, two genes, aroB and aroK, encoding rate-limiting enzymes of the shikimate pathway were overexpressed using the expression vector pIJ86 under the control of the strong constitutive ermE* promoter. The recombinant strains, S. venezuelae/pIJ86-aroB and S. venezuelae/pIJ86-aroK, produced 2.5- and 4.3-fold greater amounts respectively of chloramphenicol than wild type at early stationary phase of growth. High transcriptional levels of aroB and aroK genes were detected at the early exponential growth of both recombinant strains and consistent with the enhanced expression of pabB gene encoding an early enzyme in chloramphenicol biosynthesis. The results suggested that the increment of carbon flux was directed towards intermediates in the shikimate pathway required for the production of chorismic acid, and consequently resulted in the enhancement of chloramphenicol production. This work is the first report of a convenient genetic approach to manipulate primary metabolite genes in S. venezuelae in order to increase chloramphenicol production. PMID:26715388
Complete Genome Sequence of Streptomyces venezuelae ATCC 15439, Producer of the Methymycin/Pikromycin Family of Macrolide Antibiotics, Using PacBio Technology
He, Jingxuan; Sundararajan, Anitha; Devitt, Nicholas P.; Schilkey, Faye D.; Ramaraj, Thiruvarangan
Here, we report the complete genome sequence of Streptomyces venezuelae ATCC 15439, a producer of the methymycin/pikromycin family of macrolide antibiotics and a model host for natural product studies, obtained exclusively using PacBio sequencing technology. The 9.03-Mbp genome harbors 8,775 genes and 11 polyketide and nonribosomal peptide natural product gene clusters. PMID:27151802
Pollination biology of Eulophia alta (Orchidaceae) in Amazonia: effects of pollinator composition on reproductive success in different populations
Jürgens, Andreas; Bosch, Simone R.; Webber, Antonio C.; Witt, Taina; Frame, Dawn; Gottsberger, Gerhard
Background and Aims Spatial variation in pollinator composition and abundance is a well-recognized phenomenon. However, a weakness of many studies claiming specificity of plant–pollinator interactions is that they are often restricted to a single locality. The aim of the present study was to investigate pollinator effectiveness of the different flower visitors to the terrestrial orchid Eulophia alta at three different localities and to analyse whether differences in pollinator abundance and composition effect this plant's reproductive success. Methods Natural pollination was observed in vivo, and manipulative experiments were used to study the pollination biology and breeding system of E. alta at three sites near Manaus, Brazil. To gain a better understanding of the underlying mechanisms of pollinator attraction, nectar composition and secretion patterns were also studied, floral scent composition was analysed and a bioassay was conducted. Key Results Flower visitors, pollinator composition, pollinia transfer efficiency of particular pollinator species and natural fruit set differed among the investigated populations of E. alta. Flowers were self-compatible, partially autogamous and effectively pollinated by five bee species (four Centris species and Xylocopa muscaria). Visiting insects appeared to imbibe small amounts of hexose-rich nectar. Nectar sugar content was highest on the third day after flower opening. Floral fragrance analyses revealed 42 compounds, of which monoterpenes and benzenoids predominated. A bioassay using floral parts revealed that only floral tissue from the labellum chamber and labellum tip was attractive to flower visitors. Conclusions The data suggest that observed differences in reproductive success in the three populations cannot be explained by absolute abundance of pollinators alone. Due to behavioural patterns such as disturbance of effective pollinators on flowers by male Centris varia bees defending territory, pollinia transfer
Oblique Collision of the Leeward Antilles, Offshore Venezuela: Linking Onshore and Offshore Data from BOLIVAR
NASA Astrophysics Data System (ADS)
Beardsley, A. G.; Avé Lallemant, H. G.; Levander, A.; Clark, S. A.
The kinematic history of the Leeward Antilles (offshore Venezuela) can be characterized with the integration of onshore outcrop data and offshore seismic reflection data. Deformation structures and seismic interpretation show that oblique convergence and wrench tectonics have controlled the diachronous deformation identified along the Caribbean - South America plate boundary. Field studies of structural features in outcrop indicate one generation of ductile deformation (D1) structures and three generations of brittle deformation (F1 - F3) structures. The earliest deformation (D1/F1) began ~ 110 Ma with oblique convergence between the Caribbean plate and South American plate. The second generation of deformation (F2) structures initiated in the Eocene with the extensive development of strike-slip fault systems along the diffuse plate boundary and the onset of wrench tectonics within a large-scale releasing bend. The most recent deformation (F3) has been observed in the west since the Miocene where continued dextral strike-slip motion has led to the development of a major restraining bend between the Caribbean plate transform fault and the Oca - San Sebastian - El Pilar fault system. Deformation since the late Cretaceous has been accompanied by a total of 135° clockwise rotation. Interpretation of 2D marine reflection data indicates similar onshore and offshore deformation trends. Seismic lines that approximately parallel the coastline (NW-SE striking) show syndepositional normal faulting during F1/F2 and thrust faulting associated with F3. On seismic lines striking NNE-SSW, we interpret inversion of F2 normal faults with recent F3 deformation. We also observe both normal and thrust faults related to F3. The thick sequence of recent basin sedimentation (Miocene - Recent), interpreted from the seismic data, supports the ongoing uplift and erosion of the islands; as suggested by fluid inclusion analysis. Overall, there appears to be a strong correlation between
Seasonal to interannual depth-dependent changes in phosphorus flux in Cariaco Basin, Venezuela
NASA Astrophysics Data System (ADS)
Benitez-Nelson, C. R.; O'Neill, L.; Thunell, R.
One of the major removal pathways of phosphorus (P) from the water column is through the formation, sinking, and burial of particles formed during marine biological production. Yet the flux of P containing particles to the seafloor remains one of the least studied components of the P cycle. In this study, particulate inorganic P (PIP) and particulate organic P (POP) fluxes were measured in a series of samples collected from sediment traps ranging in depth from 275 to 1255 m from November 1995 - November 2002 in Cariaco Basin, Venezuela. PIP concentrations averaged 40- 60 % (depending on depth) of the total particulate P (TPP) measured in the traps. PIP fluxes decreased by 75 % between the surface and deep waters, from a median of 28.6 to 6.3 \\mu mol m-2 d-1, whereas POP fluxes decreased by only 50 %, from 17.2 to 8.5 \\mu mol m-2 d-1. TPP, PIP and POP all vary seasonally and higher fluxes follow higher production during the upwelling season from late January to April. The relationship between particulate organic C (POC) and POP is relatively constant (POC:POP = 283) throughout the entire water column over the entire period (r2 = 0.58). However, there is a much tighter relationship between POP and POC in upwelling (January through April, r2 = 0.85) versus non upwelling (May through December, r2 = 0.40) seasons. Furthermore, upwelling, and hence higher production appears to be associated with higher POC:POP ratios (327 versus 258 in non upwelling periods). Higher than Redfield POC:POP ratios may indicate that preferential release of P containing organic matter is occurring, but if true, it is restricted to the upper 250 m of the water column above the shallowest sediment trap. An alternative explanation may be that the composition of plankton in the Cariaco Basin does not conform to the Redfield-ratio. Plankton tow samples collected over the upper 200 m with a > 200 um mesh had POC:POP ratios of 294 +/- 38. However, there is no other evidence that the euphotic zone
Sources of δ15N variability in sinking particulate nitrogen in the Cariaco Basin, Venezuela
NASA Astrophysics Data System (ADS)
Montes, Enrique; Thunell, Robert; Muller-Karger, Frank E.; Lorenzoni, Laura; Tappa, Eric; Troccoli, Luis; Astor, Yrene; Varela, Ramón
Ten years of monthly observations of the δ15N of sinking particulate nitrogen (δ15N-PN (in ‰ versus atmospheric N2)=[(15N/14N)sample/(15N/14N)standard)-1]1000) in the Cariaco Basin, Venezuela, confirm that the basin's bottom sediments store information about nitrogen dynamics related to seasonal and interannual variability in regional surface ocean processes. During the upwelling period of the southern Caribbean Sea (February-April), the δ15N-PN is similar to that of the thermocline nitrate (˜3.5‰). This nitrate is imported into the Cariaco Basin with Subtropical Underwater (SUW), which wells up near the coast. Thus, particles generated by phytoplankton photosynthesis during this productive period bear a sub-tropical North Atlantic isotopic imprint of N2 fixation (low compared to the global average of nitrate δ15N≈5‰). During the non-upwelling period when surface waters are stratified (September-November), the δ15N-PN is also 3.5-4.0‰, and reflects a mixture of local N2 fixation within the mixed layer, inputs of terrigenous organic matter and SUW nitrate consumption by phytoplankton below the mixed layer, which most likely exerts the strongest control on the δ15N-PN signal during this time. In the transition periods of May-July and December-January, the δ15N-PN increases to 4.5-6.5‰. This coincides with maxima of continental material fluxes (terrestrial PON δ15N is >6‰) into the Cariaco Basin. The δ15N signal in the sediments of the Cariaco Basin thus provides information about the relative strength of the local coastal upwelling, the relative input of continental material via river runoff, and local N2 fixation. The findings contribute to interpretations of the basin's paleoclimatic nitrogen cycle variations based on observations of the sedimentary δ15N record at this location.
Some autecological characteristics of early to late successional tree species in Venezuela
NASA Astrophysics Data System (ADS)
Kammesheidt, Ludwig
The breadth of the continuum concept of strategy with respect to succession was tested on 21 tree and shrub species common in either unlogged or logged stands, respectively, in the Forest Reserve of Caparo, Venezuela, by examining morphological, physiological and population characteristics. Based on a preliminary abundance analysis, `early', `mid' and `late' successional species as well as `generalists' were distinguished. Early successional species, i.e. Ochroma lagopus, Heliocarpus popayanensis and Cecropia peltata were similar in many autecological aspects, e.g. monolayered leaf arrangement, orthotropic architectural models, no adaptive reiteration, clumped distribution, but differed in gap association and distribution along a drainage gradient. Mid-successional species established themselves both in large and small gaps (> 300 m[sup2 ]; 80-300 m[sup2 ]) and showed a clumped to regular distribution pattern in logged areas; they exhibited more diverse crown and leaf characteristics than early successional species. Late successional species established themselves only in small gaps and understorey, and showed a regular spatial pattern in undisturbed areas. All late successional species displayed architectural models with plagiotropic lateral axes and showed a multilayered leaf arrangement. Adaptive reiteration was a common feature of late successional species which could be further subdivided into large, medium-sized and small trees, indicating different light requirements at maturity. Generalists were common treelet and shrub species in both disturbed and undisturbed sites where they are also capable of completing their life cycle. The light compensation point (LCP) of an individual plant was strongly influenced by its crown illuminance. Large late successional species showed the widest range of LCP values, reflecting the increasing light availability with increasing height in mature forest. On the basis of many autecological characteristics, it was found (i
Low Child Survival Index in a Multi-Dimensionally Poor Amerindian Population in Venezuela
Villalba, Julian A.; Liu, Yushi; Alvarez, Mauyuri K.; Calderon, Luisana; Canache, Merari; Cardenas, Gaudymar; Del Nogal, Berenice; Takiff, Howard E.; De Waard, Jacobus H.
Background Warao Amerindians, who inhabit the Orinoco Delta, are the second largest indigenous group in Venezuela. High Warao general mortality rates were mentioned in a limited study 21 years ago. However, there have been no comprehensive studies addressing child survival across the entire population. Objectives To determine the Child Survival-Index (CSI) (ratio: still-living children/total-live births) in the Warao population, the principal causes of childhood death and the socio-demographic factors associated with childhood deaths. Methods We conducted a cross-sectional epidemiological survey of 688 women from 97 communities in 7 different subregions of the Orinoco Delta. Data collected included socio-demographic characteristics and the reproductive history of each woman surveyed. The multidimensional poverty index (MPI) was used to classify the households as deprived across the three dimensions of the Human Development Index. Multivariable linear regression and Generalized Linear Model Procedures were used to identify socioeconomic and environmental characteristics statistically associated with the CSI. Findings The average CSI was 73.8% ±26. The two most common causes of death were gastroenteritis/diarrhea (63%) and acute respiratory tract Infection/pneumonia (18%). Deaths in children under five years accounted for 97.3% of childhood deaths, with 54% occurring in the neonatal period or first year of life. Most of the women (95.5%) were classified as multidimensionally poor. The general MPI in the sample was 0.56. CSI was negatively correlated with MPI, maternal age, residence in a traditional dwelling and profession of the head of household other than nurse or teacher. Conclusions The Warao have a low CSI which is correlated with MPI and maternal age. Infectious diseases are responsible for 85% of childhood deaths. The low socioeconomic development, lack of infrastructure and geographic and cultural isolation suggest that an
Geochemical study of products associated with spontaneous oxidation of coal in the Cerro Pelado Formation, Venezuela
NASA Astrophysics Data System (ADS)
Martínez, M.; Márquez, G.; Alejandre, F. J.; Del Río, J. J.; Hurtado, A.
The aim of this research work is a geochemical, mineralogical, and textural characterization of spontaneously smouldered coal-derived products in northwestern Venezuela (Cerro Pelado Formation, some 10 km from Pedregal city). Several solid samples were collected from this formation, six of unweathering coal, an other six of resulting unmelted rocks forming on a surface coal bed, and the last four of mineralizations found accumulating around gas vents. The fresh coal and the unmelted material were analysed by scanning electron microscopy, X-ray diffraction, and proximate techniques. Products such as magnetite and chabazite-K were identified in the alteration rocks. Likewise, both materials were also studied in order to determine the mobilization of 17 elements into the environment; such elements were analysed through inductively coupled plasma atomic emission spectroscopy on extracts obtained by a sequential extraction method: each sample was firstly extracted with MilliQ water and then the resultant residue was washed. This and the subsequently resulting residues are extracted according to the mentioned procedure by using, respectively, ammonium acetate, chlorhydric acid, peroxide and chlorhydric acid, nitric acid and fluorhydric acid, and nitric acid. The studied elements are classified as highly mobile (Na, Ni, ...), nearly immobile (Ti, P) and partially mobile (Mg, Fe, K, ...). In regards to mineralizations around fumaroles associated with smoldering coal seams, Fourier-transform infrared spectroscopy and X-ray diffraction analyses have revealed the presence of salammoniac, mascagnite and other solid combustion compounds formed by reaction of gas emitted from coal oxidation, in addition to previously non-reported sulfur-rich by-products associated with gas fissures, particularly ammonium thiosulfate, a phase first obtained only synthetically in the laboratory. Another objective of the research was to collect and analyse gases escaping from surficial vents
Lithospheric expression of cenozoic subduction, mesozoic rifting and the Precambrian Shield in Venezuela
NASA Astrophysics Data System (ADS)
Masy, Jeniffer; Niu, Fenglin; Levander, Alan; Schmitz, Michael
We have combined surface wave tomography with Ps and Sp receiver-function images based on common-conversion-point (CCP) stacking to study the upper mantle velocity structure, particularly the lithosphere-asthenosphere boundary (LAB), beneath eastern and central Venezuela. Rayleigh phase velocities in the frequency range of 0.01-0.05 Hz (20-100 s in period) were measured using the two-plane-wave method and finite-frequency kernels, and then inverted on a 0.5° × 0.5° grid. The phase velocity dispersion data at grid points were inverted for 1D shear velocity profiles using initial crust-mantle velocity models constructed from previous studies. The 3D velocity model and receiver-function images were interpreted jointly to determine the depth of the LAB and other upper mantle features. The tomographic images revealed two high velocity anomalies extending to more than ∼200 km depth. One corresponds to the top of the subducting Atlantic plate beneath the Serrania del Interior. The other anomaly is a highly localized feature beneath the Maturin Basin. The LAB depth varies significantly in the study region: It is located at ∼110 km depth beneath the Guayana Shield, and reaches ∼130 km at the northern edge of the Maturin Basin, which might be related to the downward flexural bending due to thrust loading of the Caribbean plate and pull from the subducting Atlantic plate. Immediately to the west, the lithosphere is thin (∼50-60 km) along the NE-SW trending Espino Graben from the Cariaco basin to the Orinoco River at the northern edge of the craton. The LAB in this region is the top of a pronounced low velocity zone. Westward, the lithosphere deepens to ∼80 km depth beneath the Barinas Apure Basin, and to ∼90 km beneath the Neogene Merida Andes and Maracaibo block. Both upper mantle velocity structure and lithosphere thickness correlate well with surface geology and are consistent with northern South American tectonics.
Suboxic dolomite formation linked to the sedimentary Mn cycle, Archipelago Los Roques, Venezuela
NASA Astrophysics Data System (ADS)
Petrash, D.; Lalonde, S.; Gonzalez, G.; Gingras, M.; Konhauser, K.
The preferential formation of Ca-rich dolomite precursors in modern peritidal environments has been associated with the degradation of buried microbial mats, with complexation of Ca and Mg cations by extracellular polysaccharides, and alkalinity generation, mostly through bacterial sulfate reduction. However, it remains unclear why Ca-dolomite would not occur in suboxic sediments where bacterial Mn(IV) and/or Fe(III) reduction are important sources of alkalinity, and the role, if any, of Fe- and Mn-recycling in its diagenetic stabilization to more stoichiometric dolomite is unknown. In a shoaling-upward parasequence in the Archipelago Los Roques, Venezuela, an abundance of Ca-dolomite coincides with a relative decrease in bulk-sediment iron concentrations. These sediments were analyzed with multiple analytical tools, including EPMA, ICP-MS, synchrotron-based XRF, XRD, and spatially resolved XANES. Results demonstrate that the distribution of spheroidal aggregates of nanometer-scale Ca-rich dolomite rhombohedra is linked with interstitial elemental sulfur and manganese accumulations, with Mn occurring in several oxidation states (Fig. 1). Based on our observations at this novel dolomite-forming site, we suggest that in peritidal settings the burial of metal-reactive microbial mats act as a barrier capable of concentrating dissolved reactive species that promote greater sediment residence times in suboxic (manganic) zones, where the recycling of Mn not only plays an important role in the remineralization of organic matter, but also sustains elevated alkalinity and dissolved pore water sulfide concentrations. The last two effects have been previously suggested to promote Mg dehydration, the major kinetic barrier to dolomite nucleation. Figure 1. Normalized Mn K-edge merged spectra of a 5 x 5 μm analytical area bearing dolomite cements. A: The K-edge exhibits two main features at about 6554 and 6558 eV. B: Intermediate Mn (III) is identified by the positive slope of
Breeding biology of the golden-faced Tyrannulet (Zimmerius chrysops) in venezuela
Goulding, W.; Martin, T.E.
We present the first detailed information on the breeding biology of the Golden-faced Tyrannulet (Zimmerius chrysops). Information was gathered from 96 nests in Yacamb National Park, Venezuela during the 2002 to 2008 breeding seasons. The enclosed nest was similar to descriptions of nests of other species in the genus. Eggs were laid on alternate days with mean (?? SE) clutch size of 1.98 ?? 0.02 (n 45) and fresh weight of 1.616 ?? 0.020 g (n 48). Only the female incubated and the incubation period averaged 16.9 ?? 0.3 days (n 10). Nest attentiveness ( time on the nest) averaged 66.0 ?? 1.6 (n 40) and increased from early to mid- and late-incubation. Incubation behavior yielded an average 24-hr egg temperature of 34.88 ?? 0.45?? C (n 7 nests, 43 days). The nestling growth rate constant for body mass (k 0.285 ?? 0.011) was slow even for tropical tyrannids. The nestling period for nests where exact hatch and fledging days were observed ranged from 17 to 19 days with an average of 18.0 ?? 0. 2 days (n 9). Both females and males fed nestlings at a rate that increased over the nestling period with a mean of 4.41 ?? 0.65 trips/hr (n 10) during days 1 and 2 after hatching, and 14.93 ?? 2.36 trips/hr (n 6) at pin-break (days 1011). Daily predation rates were similar in egg-laying (0.052 ?? 0.025; n 76.5 exposure days) and incubation periods (0.068 ?? 0.010; n 575.5 exposure days), but were lower during the nestling period (0.039 ?? 0.010; n 377.0 exposure days). The total daily predation rate (0.057 ?? 0.007; n 989.0 exposure days) indicated only 12 of nests were successful. These breeding biology parameters for Z. chrysops differ substantially from other tyrant-flycatchers and temperate species, further highlighting the diversity within the Tyrannidae. ?? 2010 by the Wilson Ornithological Society.
Is Acropora palmata recovering? A case study in Los Roques National Park, Venezuela.
Croquer, Aldo; Cavada-Blanco, Francoise; Zubillaga, Ainhoa L; Agudo-Adriani, Esteban A; Sweet, Michael
Eight years ago (2007), the distribution and status of Acropora palmata was quantified throughout Los Roques archipelago in Venezuela. The aim was to produce a baseline study for this species which combined population genetics with demographic data. The results highlighted that A. palmata had the potential to recover in at least 6 out of 10 sites surveyed. Recovery potential was assumed to be high at sites with a relatively high abundance of the coral, low disease prevalence, high genetic diversity, and high rates of sexual reproduction. However, as noted, Zubillaga et al. (2008) realized recovery was still strongly dependent on local and regional stressors. In 2014 (this study), the status of A. palmata was re-evaluated at Los Roques. We increased the number of sites from 10 in the original baseline study to 106. This allowed us to assess the population status throughout the entirety of the MPA. Furthermore, we also identified local threats that may have hindered population recovery. Here, we show that A. palmata now has a relatively restricted distribution throughout the park, only occurring in 15% of the sites surveyed. Large stands of old dead colonies were common throughout the archipelago; a result which demonstrates that this species has lost almost 50% of its original distribution over the past decades. The majority of corals recorded were large adults (∼2 m height), suggesting that these older colonies might be less susceptible or more resilient to local and global threats. However, 45% of these surviving colonies showed evidence of partial mortality and degradation of living tissues. Interestingly, the greatest increase in partial mortality occurred at sites with the lowest levels of protection ([Formula: see text]; df = 4, p < 0.05). This may suggest there is a positive role of small scale marine management in assisting reef recovery. We also recorded a significant reduction ([Formula: see text]; df = 8; p < 0.05) in the density of A. palmata in sites
[Abundance of Diadema antillarum (Echinodermata: Echinoidea) in the coasts of Venezuela].
Noriega, Nicida; Pauls, Sheila M; del Mónaco, Carlos
Diadema antillarum is a shallow-water sea-urchin from the tropical Atlantic whose populations almost disappeared in 1983-84 because of widespread mortalities which reached 87-100 %. In Venezuela, urchin population densities before the mortality event were comparable to those of other Caribbean regions; however, later abundancies remain unknown. The objectives of this study were to evaluate the recent densities of certain D. antillarum populations along the Venezuelan coasts and compare the densities at the Parque Nacional Mochima before and after the mortality. At each location urchin densities were determined by means of transects using 1 m2-quadrats as sampling units. The highest mean densities were observed at the sites on the central coast: Ensenada de Oricao, 0.28 ind/m2 (2002) and 1.05 ind/m2 (2003), and Chichiriviche de la Costa, 0.84 ind/m2 (2002) and 0.74 ind/m2 (2003). In Mochima, the mean density before the mortality for D. antillarum oscillated between 0.28 and 4 ind/m2, after the mortality event the mean density varied between 0.15 ind/m2 (2000) and 0.47 ind/m2 (2000). The populations of D. antillarum studied at Parque Nacional Morrocoy and Refugio de Fauna Silvestre Cuare showed highest densities at Playuela (0.43 ind/m2) and Cayo Sur (0.95 ind/m2) respectively, whereas other sites showed densities below 0.1 ind/m2. The density registered at Playuela in 2003 is lower than that reported before the mortality event (0.58-3.64 ind/m2). The density for Parque Nacional Archipiélago de Los Roques, specifically for the Arrecife de Herradura remained constant between 2002 and 2003 with values between 0.22-0.23 ind/m2 respectively. To conclude, the sea urchin abundancies observed at most of the Venezuelan coastal sites that we studied were higher than those reported for other areas of the northern Caribbean, even though the values have not yet returned to those preceding the 1984 mass-mortality event, due to the slow recovery of the populations. PMID:18491619
Least Limiting Water Range of soils in the Colonia Agrícola de Turen, Venezuela
NASA Astrophysics Data System (ADS)
Perez, Maiby Yolanda; Florentino de Andreu, Adriana
Soil physical degradation is a major problem affecting the soil quality for crops production in Venezuelan agricultural areas. The least limiting water range (LLWR) is considered a soil physical quality index defined as the range in soil water content within which the limitations to plant response associated with water potential, poor aeration and high mechanical resistance are minimal. The study was carried out to characterize the LLWR and to determine the LLWR response to structural changes on soils of the Colonia Agricola de Turen, Venezuela. The soils were cropped with maize under different tillage systems (no tillage, conventional and conventional - fallow) and non-cropped under native forest. Hundred and seventy undisturbed samples were taken from specific sites under each of the above soil conditions to determine the water retention curve, the soil resistance curve and bulk density. Disturbed samples were also taken from each site to determine particle size and organic matter content. Pedotransfer functions relating the water retention curve and soil resistance curve with particle size distribution, organic matter content and bulk density were developed and use to calculate the LLWR for each site. According to the results, soil physical degradation under conventional tillage and high clay content had the highest negative impact on the LLWR. For this case (silty clay loam soil), the LLWR became narrower due to the lower water content associated with poor aeration and the higher water content associated with high mechanical resistance. In contrast, for non degraded soils with high sand content (sandy loam) the LLWR showed the highest values associated with the water content at field capacity and the water content at permanent wilting point, both the upper and lower critical limits of LLWR. For silty loam and loam soils the LLWR declined with increasing bulk density and clay content associated with water content at field capacity and water content at high
Human influence on late Holocene fluvial landscape and stratigraphy in the Mixteca Alta of Oaxaca, Mexico
NASA Astrophysics Data System (ADS)
Leigh, D. S.; Holdridge, G. H.; Kowalewski, S. A.
The Mixteca Alta of south-central Mexico (state of Oaxaca) is a high-elevation plateau where population and agricultural steadily grew over the past 3000 years, but with a few significant episodes of population decline. Currently, the landscape is highly eroded and gullied in response to widespread land abandonment and diminished population attributed to the Spanish conquest during the 1500s and 1600s. Abandonment apparently resulted in neglect of prehistoric cross-drainage retaining walls, known as lama-bordos, which had been constructed throughout agricultural watersheds for millennia to retain runoff and sediment. Our research seeks to establish the earliest ages for construction of lama-bordos, which are buried by more than 10 m of alluvium in some localities; and we hope to determine if the chronology of alluvial sedimentation is related to fluctuations in population density versus climate changes or other drivers. Sampling is focused on relatively small tributary watersheds (<10 km^2) in the valley of Rio Culebra near the town of Coixlahuaca. Our general hypothesis is counter to Malthusian theory in that we posit land degradation and erosion was punctuated by episodes of population decline when there were insufficient people to maintain the lama-bordo infrastructure. Methods involve: (1) detailed stratigraphic and pedogenic description and sampling of several outcrops; (2) radiocarbon and luminescence dating of stratigraphic sections; (3) geochemical and lithological tracing of sedimentary beds to discriminate time periods of gully erosion; (4) relating the alluvial chronology to archaeological surveys that have established the occupation history of the region. Results indicate that upland gully erosion had occurred prior to widespread human occupation of the area, because >4000 cal yr BP cut-and-fill stratigraphic units commonly contain detritus from upland subsoil and underlying bedrock. We provide numerous radiocarbon dates for the oldest lama-bordos, and
The path to modernity: a personal testimony to the restructuring of the Department of Dermatology, Vargas Hospital, Caracas, Venezuela.
Kerdel-Vegas, Francisco
In the late 1950s and early1960s, there was a concerted effort to modernize teaching, training, and patient care in the Vargas Hospital of Caracas, Venezuela. The above included the development of research in the frame of postgraduate training. This effort was to be helped by USA funds and institutions but could only be achieved by the work of Venezuelans, sharing a vision of progress. Dermatology spearheaded this initiative, and the fruit of this was the exponential development of Venezuelan Dermatology and the creation of the National Institute of Dermatology on the grounds of the Vargas Hospital. The purpose of this contribution is to review these events that happened more than half a century ago from my own perspective. I sincerely hope that these lines could serve as an inspiration to the younger generations that toil today under less-than-favorable conditions. PMID:24559570
[Growth, mortality and exploitation rate of Priacanthus arenatus (Perciformes: Priacanthidae), in the trawl fisheries of northeast Venezuela].
Toledo, J; Mendoza, J; Marcano, L
We analyzed growth, mortality and exploitation rate of Priacanhus arenatus, captured by the shrimp trawling fishery (1989-1996), in northeastern Venezuela. The growth coefficient (K) and the asymptotic length (L8) were estimated by length-frequency data using the Battacharya method and other routines of the FISAT program. Total mortality (Z) and exploitation (E) rates were obtained by length-converted catch curve analysis, based on length-frequency data, and the Berverton and Holt's yield per recruit model, respectively. The mean growth parameters L and K were estimated as 474.7 mm and 0.69 year(-1), respectively. Mean total mortality was 4.03 and the exploitation rate range was 0.70-0.80. Results indicated that the population is overexploited. PMID:15272462
The use of radar and LANDSAT data for mineral and petroleum exploration in the Los Andes region, Venezuela
NASA Technical Reports Server (NTRS)
Vincent, R. K.
A geological study of a 27,500 sq km area in the Los Andes region of northwestern Venezuela was performed which employed both X-band radar mosaics and computer processed Landsat images. The 3.12 cm wavelength radar data were collected with horizontal-horizontal polarization and 10 meter spatial resolution by an Aeroservices SAR system at an altitude of 12,000 meters. The radar images increased the number of observable suspected fractures by 27 percent over what could be mapped by LANDSAT alone, owing mostly to the cloud cover penetration capabilities of radar. The approximate eight fold greater spatial resolution of the radar images made possible the identification of shorter, narrower fractures than could be detected with LANDSAT data alone, resulting in the discovery of a low relief anticline that could not be observed in LANDSAT data. Exploration targets for petroleum, copper, and uranium were identified for further geophysical work.
Large-scale shrimp farming in coastal wetlands of Venezuela, South America: Causes and consequences of land-use conflicts
NASA Astrophysics Data System (ADS)
Sebastiani, Mirady; González, Sara Elena; Castillo, María Mercedes; Alvizu, Pablo; Oliveira, María Albertina; Pérez, Jorge; Quilici, Antonio; Rada, Martín; Yáber, María Carolina; Lentino, Miguel
In Venezuela, large-scale shrimp farming began in the 1980s. By 1987, the Ministry of Environment and Natural Resources (MARNR) had received 14 proposals for approval. A developer illegally started the construction of ponds at the Píritu Lagoon in the State of Anzoátegui before the authorization process was completed. This action triggered a land-use conflict. This study identifies the causes for public protest and determines the consequences of this conflict for land-use management. The results show that public protest was based on the impacts of the partial construction of ponds. These impacts were related to direct removal of wetlands, interruption of natural patterns of surface flows, and alteration of feeding grounds of some bird species with migratory status. Consequences were identified in relation to the role that nongovernmental organizations (NGOs) play in land-use conflicts and the actions that MARNR could take in the future to prevent and solve similar situations.
Effects of age, parity, season of calving, and sire on milk yield of Carora cows in Venezuela.
Morales, F; Blake, R W; Stanton, T L; Hahn, M V
Age-parity-season of calving, mature equivalent factors were developed for the Carora breed of Venezuela from more than 13,000 244-d milk yield records from the Venezuelan milk recording program from 1975 to 1986. Age-parity-season interactions with parity-age were most important for young cows and seasonal effects most important for old cows. Multiplicative factors were verified as useful to adjust milk yields of Carora and Brown Swiss crossbred cows. Repeatabilities for mature equivalent adjusted milk were .47, .36, and .38 between pairs of repeated records through fourth lactation. Heritability of milk in first lactation by REML procedures was 12% based on 44 Carora sires with 14 effective daughters per sire. Small population size for Carora cattle hinders usefulness and cost effectiveness of progeny testing as the primary investment in genetic gain. Greater potential economy is likely from exploiting the dams of sires genetic pathway. PMID:2794175
Debris-flow and flooding hazards associated with the December 1999 storm in coastal Venezuela and strategies for mitigation
Wieczorek, G.F.; Larsen, M.C.; Eaton, L.S.; Morgan, B.A.; Blair, J.L.
Heavy rainfall from the storm of December 14-16, 1999 triggered thousands of landslides on steep slopes of the Sierra de Avila north of Caracas, Venezuela. In addition to landslides, heavy rainfall caused flooding and massive debris flows that damaged coastal communities in the State of Vargas along the Caribbean Sea. Examination of the rainfall pattern obtained from the GOES-8 satellite showed that the pattern of damage was generally consistent with the area of heaviest rainfall. Field observations of the severely affected drainage basins and historical records indicate that previous flooding and massive debris-flow events of similar magnitude to that of December 1999 have occurred throughout this region. The volume of debris-flow deposits and the large boulders that the flows transported qualifies the 1999 event amongst the largest historical rainfall-induced debris flows documented worldwide.
Evaluation of light traps combined with carbon dioxide and 1-octen-3-ol to collect anophelines in Venezuela.
Rubio-Palis, Y
A 6-month study was carried out in northcentral Venezuela to evaluate the efficiency of the CDC light trap and the updraft ultraviolet (UV) light trap combined with carbon dioxide (CO2) or 1-octen-3-ol (or both) and human baits to sample outdoor Anopheles aquasalis and Anopheles albimanus populations. The human baits caught far more mosquitoes than did any of the other trapping methods. Comparing each of the trapping methods to the human bait catches, UV light trap + CO2 gave a closer correspondence of the ratio of An. aquasalis to An. albimanus compared with the ratio found in human baits than did any of the other trapping methods. The mean parous rate was significantly lower in human bait catches than in all of the trapping methods except for An. aquasalis in UV light trap with CO2. We consider the UV light trap with CO2 to be the most reliable substitute for human bait catches. PMID:8723264
Field application of Telazol (tiletamine hydrochloride and zolazepam hydrochloride) to immobilize wild red howler monkeys (Alouatta seniculus) in Venezuela.
Agoramoorthy, G; Rudran, R
Telazol (TEL) (tiletamine hydrochloride and zolazepam hydrochloride combination) was used to immobilize 50 wild red howler monkeys (Alouatta seniculus) in Venezuela between October 1989 and February 1991. The mean (+/- SD) dosages of TEL used for adult males and adult females were 22.4 (+/- 7.3) mg/kg and 22.5 (+/- 5.0) mg/kg, respectively. Juveniles of both sexes received a mean dose of 30.5 (+/- 5.6) mg/kg. The induction time for TEL ranged from 1 to 6.2 min. Thirteen animals were given an additional dosage of ketamine hydrochloride manually when they recovered from the first injection of TEL. Total recovery times ranged from 39 to 308 min. There were no apparent side effects to the fetuses of two pregnant females. PMID:7933286
Contact metamorphism surrounding the Alta stock: Finite element model simulation of heat- and {sup 18}O/{sup 16}O mass-transport during prograde metamorphism
Cook, S.J.; Bowman, J.R.; Forster, C.B.
Results of calcite-dolomite geothermometry and oxygen isotope studies of marbles in the southern portion of the contact aureole surrounding the Alta stock (Utah) provide evidence for extensive hydrothermal metamorphism in this part of the aureole. Simulation of these two independent data sets with two-dimensional, finite element fluid flow and heat transport models constrains the pattern of fluid flow, minimum permeability, and the permeability structure in this part of the aureole. Model results demonstrate that intrusion of the stock into a homogeneous, isotropic permeability medium yields peak metamorphic temperatures significantly lower than those measured in the marbles and significant {sup 18}O depletions both above and below the Alta-Grizzly thrust system. The latter contradicts the observations in the south aureole that {sup 18}O depletions in the marbles are restricted to marbles below the Alta-Grizzly thrust; dolomitic marbles above the thrust retain original sedimentary values up to the intrusive contact. Models with horizontal permeability barriers above the Alta-Grizzly thrust and extending over the top of the Alta stock are capable of reproducing the observed thermal and {delta}{sup 18}O profiles in the southern aureole. The presence of such horizontal barriers reduces the predominantly vertical fluid flow and heat transfer that would occur in a homogeneous and isotropic permeability medium, forcing fluid flow and heat transfer laterally away from the upper flanks of the stock. Such horizontal flow patterns are necessary to produce significant {sup 18}O depletion above the thrust, and to provide the necessary lateral heat transfer to duplicate the observed temperature profile. Best fit model results to the observed thermal and {delta}{sup 18}O profiles provide several new insights into the dynamics of fluid circulation and hydrogeologic characteristics of the southern Alta aureole during prograde metamorphism.
Elective surgery in patients with congenital coagulopathies and inhibitors: experience of the National Haemophilia Centre of Venezuela.
Boadas, A; Fernández-Palazzi, F; De Bosch, N B; Cedeño, M; Ruiz-Sáez, A
Elective surgery in patients with congenital haemophilia with inhibitors carries a high risk of bleeding. However, inhibitor patients also have a high risk of haemarthroses and other orthopaedic complications, and surgery could improve their quality of life. Successful elective surgery has been reported in inhibitor patients under haemostatic cover with plasma-derived activated prothrombin complex concentrate (pd-aPCC) or recombinant activated factor VII (rFVIIa). Recombinant FVIIa has recently become available in Venezuela and, unlike pd-aPCC, has not been associated with an anamnestic response. The aim of this study was to assess our experience using rFVIIa as a first-line and sustained treatment in elective invasive surgical procedures at the National Haemophilia Centre in Venezuela. Surgical procedures were classified as major or minor, under haemostatic cover with rFVIIa. A total of 13 patients (12 with haemophilia A with high-responding inhibitors and one with von Willebrand's disease type 3) underwent a total of 19 surgical procedures under rFVIIa cover. Thirteen procedures were classified as major surgeries. Intraoperative haemostasis was achieved in the majority of patients. Only two patients required an additional dose of rFVIIa, at 30 min and 75 min, respectively, with good results. Postoperative haemostasis was considered effective in 16 of 18 (89%) of the procedures in haemophilia A patients. Treatment was considered to be ineffective in two patients because of excessive postoperative bleeding. Data from the study provide no safety concerns, and demonstrate that rFVIIa provides effective haemostatic cover in elective surgery in patients with inhibitors; research is ongoing to determine the optimal dose for such procedures. PMID:21118333
El Furrial oil field, Northeastern Venezuela: First giant in foreland fold and thrust belts of Western Hemisphere
Not Available
The El Furrial giant oil field lies on the northern flank of the prolific Eastern Venezuela basin. Major tectonic elements of the region consist of a fold and thrust belt and a deep foreland basin, whose deformation is a product of right-oblique arc-continent collision. This mountain-front oil province displays parallel bands of thrusts and associated folds that extend over 150 mi and have relay trend patterns. The El Furrial structure is a long, doubly plunging anticline, flanked by imbricated, blind thrusts. Seismic data indicate vertical closure of about 3,000 ft over an area of 17,300 ac. The prospective section, of middle Tertiary to Late Cretaceous age, is mainly clastic, with an oil column of 1,800 ft. The interval of greater hydrocarbon potential is equated with shallow marine platform sandstones. Production tests reach sustained daily flow rates exceeding 9,500 bbl of 28/sup 0/API oil and 9,100 mcf of gas. Analysis of the oil suggests a marine Cretaceous source. Although in an early stage of development, the field is estimated to contain approximately 2 billion bbl of recoverable oil reserves. This places El Furrial in the forefront of the giant oil fields in the foreland fold and thrust belt provinces of the Western Hemisphere, second only to the supergiant accumulations of the Zagros zone in the Persian Gulf. The eastern Venezuela basin probably contains on the order of 2 trillion bbl of oil in place, making it the largest oil-bearing basin in the world. An ultimate recovery of 500 billion bbl is estimated. Therefore, the basin offers significant geologic scope for exploration for other giant fields.
Semi-Periodic Sequences and Extraneous Events in Earthquake Forecasting. II: Application, Forecasts for Japan and Venezuela
NASA Astrophysics Data System (ADS)
Quinteros Cartaya, Claudia Beatriz; Nava Pichardo, Fidencio Alejandro; Glowacka, Ewa; Frez Cárdenas, José Duglas
In order to analyze observed seismicity in central Japan and Venezuela, we applied a new method to identify semi-periodic sequences in the occurrence times of large earthquakes, which allows for the presence of multiple periodic sequences and/or events not belonging to any sequence in the time series. We also explored a scheme for diminishing the effects of a sharp cutoff magnitude threshold in selecting the events to analyze. A main four-event sequence with probability P c = 0.991 of not having occurred by chance was identified for earthquakes with M ≥ 8.0 in central Japan. Venezuela is divided, from West to East, into four regions; for each of these, the magnitude ranges and identified sequences are as follows. Region 1: M ≥ 6.0, a six-event sequence with P c = 0.923, and a four-event sequence with P c = 0.706. Region 2: M ≥ 5.6, a five-event sequence with P c = 0.942. Region 3: M ≥ 5.6, a four-event sequence with P c = 0.882. Region 4: M ≥ 6.0, a five-event sequence with P c = 0.891. Forecasts are made and evaluated for all identified sequences having four or more events and probabilities ≥0.5. The last event of all these sequences was satisfactorily aftcast by previous events. Whether the identified sequences do, in fact, correspond to physical processes resulting in semi-periodic seismicity is, of course, an open question; but the forecasts, properly used, may be useful as a factor in seismic hazard estimation.
Cenozoic uplift of the Northerm Margin of the Guayana Shield, Venezuela, and its influence on the distribution of mineral deposits
Olmore, S.D. ); Garcia, A. ); Antonia, S.C. )
We present new ideas regarding the Cenozoic intraplate tectonics of the northern margin of the Guayana Shield. During Caribbean Orogeny tectonic transpression induced by right-lateral shear brought about the uplift of a 500 km by 200 km, east-northeast-trending elongate region south of the Orinoco River in south-central Venezuela-Uplifted Imataca Block (UIB). Erosional stripping of mineralized greenstone units from the UIB exposed a high-grade metamorphic core of quartz-feldspar granulite gneiss of Archean age. A 1000-meter-thick section of deltaic sediments from erosion of the UIB were deposited in the marginal basin to the north during Miocene and younger time. These sedimentary units host the Orinoco heavy-oil belt. The UIB is bounded on the north by a series of east-northeast-trending step faults that lie along the approximate trace of the Orinoco River. The UIB is bounded on the south by the Guri fault zone. Numerous sub-parallel faults within the exposed Archean block show evidence of late Cenozoic, post-uplift, right-lateral and normal displacement. Some conclusions: (1) high-grade Archean granulite or praqneiss may underlie portions of the Proterozoic greenstone and granite-gneiss terrain of the Guayana shield to the south; (2) differences in El Pao and Cerro Bolivar iron ores are explained by differential erosional stripping accompanying block uplift. (3) The juxtaposition of oil-bearing Cenozoic sediments and metal-rich Archean and lower Proterozoic greenstone units by Mesozoic and Cenozoic faulting makes central Venezuela one of the richest mineral-bearing provinces of the world.
Is Acropora palmata recovering? A case study in Los Roques National Park, Venezuela
Cavada-Blanco, Francoise; Zubillaga, Ainhoa L.; Agudo-Adriani, Esteban A.; Sweet, Michael
Eight years ago (2007), the distribution and status of Acropora palmata was quantified throughout Los Roques archipelago in Venezuela. The aim was to produce a baseline study for this species which combined population genetics with demographic data. The results highlighted that A. palmata had the potential to recover in at least 6 out of 10 sites surveyed. Recovery potential was assumed to be high at sites with a relatively high abundance of the coral, low disease prevalence, high genetic diversity, and high rates of sexual reproduction. However, as noted, Zubillaga et al. (2008) realized recovery was still strongly dependent on local and regional stressors. In 2014 (this study), the status of A. palmata was re-evaluated at Los Roques. We increased the number of sites from 10 in the original baseline study to 106. This allowed us to assess the population status throughout the entirety of the MPA. Furthermore, we also identified local threats that may have hindered population recovery. Here, we show that A. palmata now has a relatively restricted distribution throughout the park, only occurring in 15% of the sites surveyed. Large stands of old dead colonies were common throughout the archipelago; a result which demonstrates that this species has lost almost 50% of its original distribution over the past decades. The majority of corals recorded were large adults (∼2 m height), suggesting that these older colonies might be less susceptible or more resilient to local and global threats. However, 45% of these surviving colonies showed evidence of partial mortality and degradation of living tissues. Interestingly, the greatest increase in partial mortality occurred at sites with the lowest levels of protection (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${X}_{o}^{2
Oxygen Isotope and Microtextural Evidence for Fluctuations in Fluid Pressure During Contact Metamorphism, Alta Aureole, Utah, USA
NASA Astrophysics Data System (ADS)
Bowman, J. R.; Valley, J. W.; Kita, N.
Thin section-scale textures record a detailed history of prograde and retrograde reactions in the periclase (Per) zone of the Alta Stock aureole. New ion microprobe (SIMS) measurements (10 micron spot, ±0.2 permil, 1sd) of the oxygen isotope compositions of the carbonates preserving these textures provide evidence for at least two cycles of oscillation of fluid pressure (Pfl) between lithostatic (PL) and hydrostatic (Phyd) conditions during evolution of the inner aureole. Infiltration of water-rich fluids during prograde metamorphism converted dolomite (Dol) to Per + calcite (Cal) marble and caused significant 18O/16O depletion in the Dol protolith (Initial δ18O (Cal) > +25 permil), producing Cal with δ18O values of +11 permil. The SIMS values approximate oxygen isotope exchange equilibrium with the Alta stock, indicating that infiltrating fluids were likely magmatic. Exsolution of fluid from the crystallizing magma, coupled with geothermometry from the periclase zone marbles, requires Pfl> PL. Horizontally-oriented expansion cracks filled with brucite (Br) extend from Br pseudomorphs after periclase, and cut retrograde Dol that partially to completely rims the Br pseudomorphs. This earlier retrograde Dol is significantly depleted in 18O/16O relative to matrix Cal, with δ18O of +5 to +7.1 permil. These lower δ18O values indicate that meteoric water infiltrated into the Per marbles during cooling and resulting partial back reaction of Per + Cal to Dol, prior to the hydration of the remaining Per to Br. Influx of meteoric water requires sufficient increase in permeability to permit surface- derived meteoric water to penetrate to the estimated 4.5 km depth of this structural level of the Alta aureole, and suggests a resulting decrease in Pfl to hydrostatic pressure conditions. The horizontally-oriented expansion cracks associated with the Br pseudomorphs indicate that sub-vertical expansion accompanied hydration of Per to Br, requiring that Pfl increase again to
Trypanosoma cruzi III from armadillos (Dasypus novemcinctus novemcinctus) from Northeastern Venezuela and its biological behavior in murine model. Risk of emergency of Chagas' disease.
Morocoima, Antonio; Carrasco, Hernán J; Boadas, Johanna; Chique, José David; Herrera, Leidi; Urdaneta-Morales, Servio
Trypanosoma cruzi, etiological agent of Chagas' disease, was isolated from armadillos (Dasypus novemcinctus novemcinctus) captured in rural communities Northeastern Venezuela from Nueva Esparta State (no endemic for Chagas' disease), Monagas and Anzoátegui States (endemics). The isolates, genetically typed by PCR-RFLP as belonging to the TcIII DTU, have demonstrated in murine model heterogenic parasitemia, mortality and histotropism with marked parasitism in cardiac, skeletal, and smooth myocytes that showed correlation with lymphobasophilic inflammatory infiltrates. Our finding of T. cruzi infected armadillos in Isla Margarita (Nueva Esparta State), together with reports of triatomine vectors in this region, the accentuated synanthropy of armadillos, intense economic activity, migration due to tourism and the lack of environmental education programs all of them represent risks that could cause the emergence of Chagas' disease in this area. This is the first report of the TcIII DTU in Northeastern Venezuela, thus widening the geographic distribution of this DTU. PMID:22902748
A new species of Parichoronyssus (Acari: Dermanyssoidea: Macronyssidae) from bats of the genus Phyllostomus (Chiroptera: Phyllostomidae) in Peru and Venezuela, with keys to the species of Parichoronyssus.
Morales-Malacara, Juan B; Guerrero, Ricardo
Parichoronyssus bakeri new species was found on two phyllostomid bats species, the greater spear-nosed bat, Phyllostomus hastatus (Pallas), and the lesser spear-nosed bat, Phyllostomus elongatus (E. Geoffroy), in Pakitza, National Park Manu, Madre de Dios, Peru, including additional material examined from Venezuela. The female, male, deutonymph, and protonymph are described and illustrated. A key to the seven species of Parichoronyssus is provided. PMID:17294915
Reconstruction of Sea/Lake-Level Changes in an Active Strike-Slip Basin (Gulf of Cariaco, NE Venezuela)
NASA Astrophysics Data System (ADS)
van Daele, M.; Audemard, F.; Beck, C.; de Batist, M.; van Welden, A.; Moernaut, J.; 2006 Shipboard Party, G.
In January 2006, 76 high-resolution reflection seismic profiles were acquired in the Gulf of Cariaco, Northeast Venezuela. In the upper 100 m of sedimentary infill, 17 unconformity-bounded sequences were identified and mapped throughout the basin. Up to now, no core or borehole information is available to provide age constraints on these units. The sedimentary infill is cut by several faults, Riedel faults in the central part and the El Pilar fault (one of the main faults of the South American-Caribbean plate boundary) in the southern part of the gulf. The connection of the Gulf of Cariaco with the adjacent Cariaco Basin occurs at a present-day water depth of ~ 55 m. This implies that the gulf was disconnected from the world ocean and functioned as a lake during a large part of the last glacial. The main rivers entering the gulf drain the coastal mountain ranges and tend to form pronounced deltas at their inlet. During times when the gulf was a lake, periods with a dry climate resulted in dramatic lake-level lowstands and even complete desiccation/evaporation. The present-day depths of delta offlap breaks and the presence of lowstand/evaporite deposits can thus be used to estimate sea/lake level at the time of their formation. Detailed analysis of these stratigraphic sea/lake-level indicators allowed reconstructing the sea/lake-level history for the period encompassed by the 17 identified sequences. This sea/lake-level reconstruction also needed to be corrected for tectonic subsidence, affecting different parts of the gulf with different intensity. The reconstructed sea/lake-level curve of the Gulf of Cariaco was compared with the eustatic sea-level curve and with results of previous paleoclimate studies in Venezuela. The striking coherence between the eustatic curve and the amplitudes and absolute heights of successive reconstructed lowstands and highstands compelled us to tune our record to the eustatic curve in order to achieve a rough age estimate for our units
[Vitamin A deficiency and the anthropometric nutritional status of urban and rural marginalized children in the state of Zulia, Venezuela].
Amaya-Castellanos, Daisy; Viloria-Castejón, Haydée; Ortega, Pablo; Gómez, Gisela; Urrieta, Jesús R; Lobo, Pablo; Estévez, Jesús
The present transversal study was carried out to estimate the prevalence of both vitamin A deficiency (VAD) and protein-energy malnutrition among children (24 to 85 months) from three urban slums (n = 173) in Maracaibo city, Zulia State, Venezuela and a rural slum area (n = 34), vieinal to Maracaibo, by measuring serum retinol and z score of anthropometric indices Height//Age (H//AZ); Weight//Age (W//AZ) and Weight//Height (W//HZ), compared to NCHS-WHO reference values. The Graffar's methodology adapted to Venezuela by Méndez Castellano (1986) confirmed the underprivileged socio-economic condition of the children population. For serum retinol analysis, peripheral venous blood was drawn and serum was treated according to the Bieri et al. (1979) technique and HPLC procedure. Values were recorded in microgram/dL. Statistical analysis was done by using Epi Info 2000, release 1.0 and SAS release 6.0 (1996) computer programs. The prevalence of VAD (serum retinol < 20 micrograms/dL) in the total children population (n = 207) was 22.2%, being higher in urban children than in rural children (22.5% vs 20.5%). No clinical signs of VAD were detected in the children. The nutritional status analysed by Z score of anthropometric indices revealed that 27.4% of children suffered from undernutrition (Z score = -2 to > -3 SD), being 15.4% stunted, 9.6% wasted and 2.6% with acute protein-energy malnutrition. Neither severe malnutrition nor overweight were detected. According with the H//AZ index, 54.6% of children had adequate nutrition. However 23% of them suffered from VAD. In children at risk of developing undernutrition (Z score = -1 to > -2 SD), 20.9% had VAD and of the stunted children, 21.9% presented VAD. With W//AZ, 60.3%, 29.9% and 9.1% of children were with adequate nutrition, at risk, or wasted respectively; of each group, 25.6%, 17.7% and 15%, respectively had serum retinol values below 20 micrograms/dL. The Z score of W//HZ indicator revealed that 87.4%, 10.4% and 2
Mapping lithosphere thickness beneath the Southern Caribbean and Venezuela using body wave reflectivity and surface wave tomography
NASA Astrophysics Data System (ADS)
Masy, J.; Niu, F.; Levander, A.; Schmitz, M.
The Caribbean (CAR) and South American (SA) plate boundary in Venezuela is a broad zone of diffuse deformation and faulting. GPS measurements indicate that the CAR is moving approximately 2 cm/yr respect to SA, parallel to the strike slip fault system in the east, but with an oblique convergence component in the west (Weber et al., 2001). Along the central and eastern Venezuela coast, most of the motion is accommodated by both transpression and transtension along the right lateral strike-slip San Sebastian- El Pilar fault system. The main tectonic features of the area include accretionary wedges and coastal thrust belts with their associated foreland basins (e.g. Sierra del Interior and Espino Graben). Southern of the plate boundary is located the Guayana Shield, which is part of the Amazonian Craton, and is an elevated plain consisting of Precambrian rocks. BOLIVAR (Broadband Onshore-Offshore Lithospheric Investigation of Venezuela and the Antilles Arc Region) was a multidisciplinary, international investigation to determine the evolution of the CAR-SA plate boundary (Levander et al., 2006) that included a 47 station broadband seismic array to complement the 40 station Venezuelan national array operated by FUNVISIS. The goal of this study is to map out lithosphere thickness across the region in order to understand its role for the various types of deformations observed at surface. We combined surface wave tomography and body wave reflectivity to locate the depth of the lithosphere-asthenosphere boundary (LAB). To generate a coherent 3D reflectivity volume of the study area, we used both P- and S-wave receiver-function data, as well as the ScS reverberation records of two deep earthquakes occurring in South America. We also measured Rayleigh phase velocities in the frequency range of 20-100 s using the two plane-wave method to remove multi-pathing effects (Forsyth and Li, 2005). Finite-frequency kernels were computed for a total of 63 teleseismic events to improve
Mycobacterium tuberculosis ecology in Venezuela: epidemiologic correlates of common spoligotypes and a large clonal cluster defined by MIRU-VNTR-24
Background Tuberculosis remains an endemic public health problem, but the ecology of the TB strains prevalent, and their transmission, can vary by country and by region. We sought to investigate the prevalence of Mycobacterium tuberculosis strains in different regions of Venezuela. A previous study identified the most prevalent strains in Venezuela but did not show geographical distribution nor identify clonal genotypes. To better understand local strain ecology, we used spoligotyping to analyze 1298 M. tuberculosis strains isolated in Venezuela from 1997 to 2006, predominantly from two large urban centers and two geographically distinct indigenous areas, and then studied a subgroup with MIRU-VNTR 24 loci. Results The distribution of spoligotype families is similar to that previously reported for Venezuela and other South American countries: LAM 53%, T 10%, Haarlem 5%, S 1.9%, X 1.2%, Beijing 0.4%, and EAI 0.2%. The six most common shared types (SIT's 17, 93, 605, 42, 53, 20) accounted for 49% of the isolates and were the most common in almost all regions, but only a minority were clustered by MIRU-VNTR 24. One exception was the third most frequent overall, SIT 605, which is the most common spoligotype in the state of Carabobo but infrequent in other regions. MIRU-VNTR homogeneity suggests it is a clonal group of strains and was named the "Carabobo" genotype. Epidemiologic comparisons showed that patients with SIT 17 were younger and more likely to have had specimens positive for Acid Fast Bacilli on microscopy, and patients with SIT 53 were older and more commonly smear negative. Female TB patients tended to be younger than male patients. Patients from the high incidence, indigenous population in Delta Amacuro state were younger and had a nearly equal male:female distribution. Conclusion Six SIT's cause nearly half of the cases of tuberculosis in Venezuela and dominate in nearly all regions. Strains with SIT 17, the most common pattern overall may be more actively
An observatory system for physical and biogeochemical parameters in the northern Adriatic Sea: the "Acqua Alta" oceanographic platform
NASA Astrophysics Data System (ADS)
Benetazzo, Alvise; Barbariol, Francesco; Bastianini, Mauro; Bergamasco, Andrea; Bergamasco, Filippo; Bernardi Aubry, Fabrizio; Bertotti, Luciana; Bonaldo, Davide; Cavaleri, Luigi; Carniel, Sandro; Falcieri, Francesco M.; Finotto, Stefania; Lester, Graham; Licer, Matjaz; Malacic, Vlado; Minuzzo, Tiziano; Sclavo, Mauro
The history of the "Acqua Alta" oceanographic platform (http://www.ismar.cnr.it/infrastructures/piattaforma-acqua-alta) started more than forty years ago, shortly after the dramatic surge that affected the city of Venice in late 1966. Since then, benefiting also from recent funding acquired within the National Flagship Project RITMARE, great efforts have been devoted to monitor the oceanographic and atmospheric conditions in the Northern Adriatic Sea (NA), in the proximity of the Venice lagoon. Nowadays the "Acqua Alta", located on a 16 m depth area, represents a success story of the Institute of Marine Sciences (ISMAR) of the Italian National Research Council (CNR), that manages the structure and used collected data to improve the knowledge of the fragile sea environment that surrounds the Venetian littoral. The directional wave observations started in 1979, representing one of the world longest continuous series. On the sea surface, waves are now routinely observed by means of a submerged acoustic-Doppler system that provides burst of directional wave data, including significant wave height, mean wave period and direction of propagation. Currently these wave parameters are integrated with the data collected by a stereo-video system (namely Wave Acquisition Stereo System, WASS) that provides the 3-D profile of the wavy sea surface. WASS data are unleashing a "new view" for ocean waves providing the complete space-time dynamics of wave groups. Moreover, a series of multiparameters probes permits to measure the vertical distribution of sea temperature (at nine depths from the surface to the bottom), salinity (three positions), dissolved oxygen (two positions), and turbidity close to the sea bottom. The collected data are continuously used to track the water masses that enter, leave, and are produced within the NA. A striking example is provided by the temperature and salinity data used to follow the exceptional dense water formation that occurred in this basin
An observatory system for physical and biogeochemical parameters in the northern Adriatic Sea: the "Acqua Alta" oceanographic platform
NASA Astrophysics Data System (ADS)
Benetazzo, Alvise; Barbariol, Francesco; Bastianini, Mauro; Bergamasco, Andrea; Bergamasco, Filippo; Bernardi Aubry, Fabrizio; Bertotti, Luciana; Bonaldo, Davide; Cavaleri, Luigi; Carniel, Sandro; Falcieri, Francesco M.; Finotto, Stefania; Lester, Graham; Licer, Matjaz; Malacic, Vlado; Minuzzo, Tiziano; Sclavo, Mauro
The history of the "Acqua Alta" oceanographic platform (http://www.ismar.cnr.it/infrastructures/piattaforma-acqua-alta) started more than forty years ago, shortly after the dramatic surge that affected the city of Venice in late 1966. Since then, benefiting also from recent funding acquired within the National Flagship Project RITMARE, great efforts have been devoted to monitor the oceanographic and atmospheric conditions in the Northern Adriatic Sea (NA), in the proximity of the Venice lagoon. Nowadays the "Acqua Alta", located on a 16 m depth area, represents a success story of the Institute of Marine Sciences (ISMAR) of the Italian National Research Council (CNR), that manages the structure and used collected data to improve the knowledge of the fragile sea environment that surrounds the Venetian littoral. The directional wave observations started in 1979, representing one of the world longest continuous series. On the sea surface, waves are now routinely observed by means of a submerged acoustic-Doppler system that provides burst of directional wave data, including significant wave height, mean wave period and direction of propagation. Currently these wave parameters are integrated with the data collected by a stereo-video system (namely Wave Acquisition Stereo System, WASS) that provides the 3-D profile of the wavy sea surface. WASS data are unleashing a "new view" for ocean waves providing the complete space-time dynamics of wave groups. Moreover, a series of multiparameters probes permits to measure the vertical distribution of sea temperature (at nine depths from the surface to the bottom), salinity (three positions), dissolved oxygen (two positions), and turbidity close to the sea bottom. The collected data are continuously used to track the water masses that enter, leave, and are produced within the NA. A striking example is provided by the temperature and salinity data used to follow the exceptional dense water formation that occurred in this basin
Health Seeking Behaviour and Treatment Intentions of Dengue and Fever: A Household Survey of Children and Adults in Venezuela
Elsinga, Jelte; Lizarazo, Erley F.; Vincenti, Maria F.; Schmidt, Masja; Velasco-Salas, Zoraida I.; Arias, Luzlexis; Bailey, Ajay; Tami, Adriana
Background Dengue in Venezuela is a major public health problem with an increasing incidence of severe cases. Early diagnosis and timely treatment influences the outcome of dengue illness, as delay in care-seeking is significantly associated with complications leading to severe dengue. We aimed to understand patterns of health seeking behaviour (HSB) in individuals exposed to high dengue incidence in order to improve early attendance to health centres. Methods Between September 2013 and February 2014 a cross-sectional household survey was performed in Maracay, Venezuela. Intended HSB of adults and children's parents/guardians was assessed with respect to fever or suspected dengue. Data was collected through structured questionnaires from 105 individuals. Results Most individuals felt at risk of dengue and believed it could be a deadly disease. In the case of suspected dengue, the majority (60%) would choose to first seek medical help versus first treating at home, in contrast to 11% in the case of fever. Amongst those who decided to visit a doctor, a suspected dengue infection would prompt them to search medical help earlier than if having only fever (p<0.001). Multivariate analysis modelling showed that the independent factors associated with the intention to firstly visit a doctor versus treating at home in the case of dengue were feeling at risk (OR = 3.29; p = 0.042) and being an adult (as opposed to caring for a child as a parent/guardian; OR = 3.33, p = 0.021), while having had a previous dengue infection (OR = 0.29; p = 0.031) and living in the neighbourhood Caña de Azúcar (OR = 0.28, p = 0.038) were negatively associated with seeking medical care as their first action. Conclusion Knowledge of HSB related to dengue is scarce in the Americas, our study attempts to contribute to a better understanding of HSB in this region. Improving early dengue disease recognition and awareness may enhance prompt attendance to medical care in affected populations and
Recurrent wheezing is associated with intestinal protozoan infections in Warao Amerindian children in Venezuela: a cross-sectional survey
Background While in developed countries the prevalence of allergic diseases is rising, inflammatory diseases are relatively uncommon in rural developing areas. High prevalence rates of helminth and protozoan infections are commonly found in children living in rural settings and several studies suggest an inverse association between helminth infections and allergies. No studies investigating the relationship between parasitic infections and atopic diseases in rural children of developing countries under the age of 2 years have been published so far. We performed a cross-sectional survey to investigate the association of helminth and protozoan infections and malnutrition with recurrent wheezing and atopic eczema in Warao Amerindian children in Venezuela. Methods From August to November 2012, 229 children aged 0 to 2 years residing in the Orinoco Delta in Venezuela were enrolled. Data were collected through standardized questionnaires and physical examination, including inspection of the skin and anthropometric measurements. A stool sample was requested from all participants and detection of different parasites was performed using microscopy and real time polymerase chain reaction (PCR). Results We observed high prevalence rates of atopic eczema and recurrent wheezing, respectively 19% and 23%. The prevalence of helminth infections was 26% and the prevalence of protozoan infections was 59%. Atopic eczema and recurrent wheezing were more frequently observed in stunted compared with non-stunted children in multivariable analysis (OR 4.3, 95% CI 1.3 – 13.6, p = 0.015 and OR 4.5, 95% CI 0.97 – 21.2, p = 0.055). Furthermore, recurrent wheezing was significantly more often observed in children with protozoan infections than in children without protozoan infections (OR 6.7, 95% CI 1.5 – 30.5). Conclusions High prevalence rates of atopic eczema and recurrent wheezing in Warao Amerindian children under 2 years of age were related to stunting and intestinal
[Viability and activity of the lactic bacteria (Streptococcus salivarius ssp thermophilus y Lactobacillus delbrueckii ssp bulgaricus) del yogurt en Venezuela].
Briceño, A G; Martínez, R; García, K
National and international legislations have agreed that the population of lactic bacteria in yogurt must be viable and not less than 10(6) ufc/g. In Venezuela, during last years, observations indicate that the number of viable cells in some commercial samples show high variations, as low levels. This research attempted to find the origin of this problem in the local industry. For this purpose 105 commercial samples were analyzed during their shelf life and 32 samples of yogurt prepared in the laboratory following the flow diagram of the local industry. The different conditions of freeze dried lactic culture, were also analyzed. These samples were evaluated for viable cell count of lactic bacteria and possible variations of pH and acidity. The absence or low number of lactic bacteria detected in some commercial samples is due to the use of inadequate working cultures that show imbalanced proportions of the two microorganisms, besides a low count below 106 ufc/g. The succesive propagation and storage time of mother culture, and the overacidification of the product, produce subletal injury to the microbial cells of the yogurt starter culture. The data indicate that manufacturing practices significantly affect the survival of the lactic flora. PMID:11510428
Crustal structure in the Falcón Basin area, northwestern Venezuela, from seismic and gravimetric evidence
NASA Astrophysics Data System (ADS)
Bezada, Maximiliano J.; Schmitz, Michael; Jácome, María Inés; Rodríguez, Josmat; Audemard, Franck; Izarra, Carlos; The Bolivar Active Seismic Working Group
The Falcón Basin in northwestern Venezuela has a complex geological history driven by the interactions between the South American and Caribbean plates. Igneous intrusive bodies that outcrop along the axis of the basin have been associated with crustal thinning, and gravity modeling has shown evidence for a significantly thinned crust beneath the basin. In this study, crustal scale seismic refraction/wide-angle reflection data derived from onshore/offshore active seismic experiments are interpreted and forward-modeled to generate a P-wave velocity model for a ˜450 km long profile. The final model shows thinning of the crust beneath the Falcón Basin where depth to Moho decreases to 27 km from a value of 40 km about 100 km to the south. A deeper reflected phase on the offshore section is interpreted to be derived from the downgoing Caribbean slab. Velocity values were converted to density and the resulting gravimetric response was shown to be consistent with the regional gravity anomaly. The crustal thinning proposed here supports a rift origin for the Falcón Basin.
[Sponges (porifera) distribution along a depth gradient in a coral reef, Parque Nacional San Esteban, Carabobo, Venezuela].
Núñez Flores, Mónica; Rodríguez-Quintal, José Gregorio; Cristina Díaz, María
Sponges constitute one of the most diverse and abundant animal groups in the marine tropical benthos especially in coral reefs, though poorly studied to species level. The aim of this study is to characterize the sponge community along a depth gradient at Isla Larga (Parque Nacional San Esteban, Venezuela) fringe reef. Net and total sedimentation, roughness index, sponge species richness, density and proportion of the bottom covered by sponges, were evaluated at seven depths (1, 3, 6, 9, 12, 15, 18 m), 17 species were identified grouped in 10 demosponges families. The highest densities and coverage corresponded to 6 m of depth (6.03ind/m2; 11%), that coincides with the lowest net sedimentation and highest substrate heterogeneity. Most abundant species were Desmapsamma anchorata, Amphimedon erina and Scopalina rueztleri. Principal component analysis divided this community in three zones according to depth. The shallow zone of the reef (1 and 3 m), where wave force and high irradiance exert a constant stress sponges, shows the lowest density and coverage by sponges. In contrast, medium depth (6, 9 y 12 m) and deep zone (15 y 18 m) with lower light and sedimentation levels seem to enhance sponge growth and survival that are reflected on the higher densities and coverage of sponges. PMID:21302530
Characterization of a putative NsrR homologue in Streptomyces venezuelae reveals a new member of the Rrf2 superfamily.
Munnoch, John T; Martinez, Ma Teresa Pellicer; Svistunenko, Dimitri A; Crack, Jason C; Le Brun, Nick E; Hutchings, Matthew I
Members of the Rrf2 superfamily of transcription factors are widespread in bacteria but their functions are largely unexplored. The few that have been characterized in detail sense nitric oxide (NsrR), iron limitation (RirA), cysteine availability (CymR) and the iron sulfur (Fe-S) cluster status of the cell (IscR). In this study we combined ChIP- and dRNA-seq with in vitro biochemistry to characterize a putative NsrR homologue in Streptomyces venezuelae. ChIP-seq analysis revealed that rather than regulating the nitrosative stress response like Streptomyces coelicolor NsrR, Sven6563 binds to a conserved motif at a different, much larger set of genes with a diverse range of functions, including a number of regulators, genes required for glutamine synthesis, NADH/NAD(P)H metabolism, as well as general DNA/RNA and amino acid/protein turn over. Our biochemical experiments further show that Sven6563 has a [2Fe-2S] cluster and that the switch between oxidized and reduced cluster controls its DNA binding activity in vitro. To our knowledge, both the sensing domain and the putative target genes are novel for an Rrf2 protein, suggesting Sven6563 represents a new member of the Rrf2 superfamily. Given the redox sensitivity of its Fe-S cluster we have tentatively named the protein RsrR for Redox sensitive response Regulator. PMID:27605472
Characterization of a putative NsrR homologue in Streptomyces venezuelae reveals a new member of the Rrf2 superfamily
Munnoch, John T.; Martinez, Ma Teresa Pellicer; Svistunenko, Dimitri A.; Crack, Jason C.; Le Brun, Nick E.; Hutchings, Matthew I.
Members of the Rrf2 superfamily of transcription factors are widespread in bacteria but their functions are largely unexplored. The few that have been characterized in detail sense nitric oxide (NsrR), iron limitation (RirA), cysteine availability (CymR) and the iron sulfur (Fe-S) cluster status of the cell (IscR). In this study we combined ChIP- and dRNA-seq with in vitro biochemistry to characterize a putative NsrR homologue in Streptomyces venezuelae. ChIP-seq analysis revealed that rather than regulating the nitrosative stress response like Streptomyces coelicolor NsrR, Sven6563 binds to a conserved motif at a different, much larger set of genes with a diverse range of functions, including a number of regulators, genes required for glutamine synthesis, NADH/NAD(P)H metabolism, as well as general DNA/RNA and amino acid/protein turn over. Our biochemical experiments further show that Sven6563 has a [2Fe-2S] cluster and that the switch between oxidized and reduced cluster controls its DNA binding activity in vitro. To our knowledge, both the sensing domain and the putative target genes are novel for an Rrf2 protein, suggesting Sven6563 represents a new member of the Rrf2 superfamily. Given the redox sensitivity of its Fe-S cluster we have tentatively named the protein RsrR for Redox sensitive response Regulator. PMID:27605472
Organic geochemical investigation and coal-bed methane characteristics of the Guasare coals (Paso Diablo mine, western Venezuela)
Quintero, K.; Martinez, M.; Hackley, P.; Marquez, G.; Garban, G.; Esteves, I.; Escobar, M.
The aim of this work was to carry out a geochemical study of channel samples collected from six coal beds in the Marcelina Formation (Zulia State, western Venezuela) and to determine experimentally the gas content of the coals from the Paso Diablo mine. Organic geochemical analyses by gas chromatography-mass spectrometry and isotopic analyses on-line in coalbed gas samples were performed. The results suggest that the Guasare coals were deposited in a continental environment under highly dysoxic and low salinity conditions. The non-detection of 18??(H)-oleanane does not preclude that the organic facies that gave rise to the coals were dominated by angiosperms. In addition, the presence of the sesquiterpenoid cadalene may indicate the subordinate contribution of gymnosperms (conifers) in the Paleocene Guasare mire. The average coalbed gas content obtained was 0.6 cm3/g. ??13C and D values indicate that thermogenic gas is prevalent in the studied coals. Copyright ?? Taylor & Francis Group, LLC.
Structure of the Cordillera de la Costa Belt, North-Central Venezuela: Implications for plate tectronic models
Ave Lallemant, H.G.; Sisson, V.B.; Wright, J.E. )
Preliminary results of an on-going study of the Cordillera de la Costa belt between Puerto Cabello and Choroni, north-central Venezuela, indicate that the deformational history is far more complicated than expected from simple plate-tectonic models. The Cordillera de la Costa belt consists of oceanic rocks (e.g., serpentinites, amphibilites, with lenses of eclogite and blueschist) intimately intermixed with metamorphosed continental margin deposits (e.g., mica and graphite schist, quartzite, marble). Locally, large granitic (basement ) complexes of Lower Paleozoic age are included as well. In late Cretaceous time, the entire belt was involved in four synmetamorphic deformations phases (D[sub 1a] to D[sub 1d]); the first (D[sub 1a]) occurred at depths of at 35-40 km and the later ones at successively shallower depths. This deformation occurred in a subduction zone, related to right-oblique convergence of the Farallon and Atlantic plates. The most penetrative structures resulted from (all in present coordinates) north-south contraction and east-west dextral simple shear (D[sub 1b]). During an Early Tertiary ( ) event (D[sub 2]), the belt was emplaced southward onto the South American continental margin. Subsequent deformational structures (D[sub 3]) resulted in cross folds and faults (with small pull-apart basins) which are consistent with the eastward passage of the Caribbean past the South American plate.
Approaches to identifying reservoir heterogeneity and reserve growth opportunities from subsurface data: The Oficina Formation, Budare field, Venezuela
Hamilton, D.S.; Raeuchle, S.K.; Holtz, M.H.
We applied an integrated geologic, geophysical, and engineering approach devised to identify heterogeneities in the subsurface that might lead to reserve growth opportunities in our analysis of the Oficina Formation at Budare field, Venezuela. The approach involves 4 key steps: (1) Determine geologic reservoir architecture; (2) Investigate trends in reservoir fluid flow; (3) Integrate fluid flow trends with reservoir architecture; and (4) Estimate original oil-in-place, residual oil saturation, and remaining mobile oil, to identify opportunities for reserve growth. There are three main oil-producing reservoirs in the Oficina Formation that were deposited in a bed-load fluvial system, an incised valley-fill, and a barrier-strandplain system. Reservoir continuity is complex because, in addition to lateral facies variability, the major Oficina depositional systems were internally subdivided by high-frequency stratigraphic surfaces. These surfaces define times of intermittent lacustrine and marine flooding events that punctuated the fluvial and marginal marine sedimentation, respectively. Syn and post depositional faulting further disrupted reservoir continuity. Trends in fluid flow established from initial fluid levels, response to recompletion workovers, and pressure depletion data demonstrated barriers to lateral and vertical fluid flow caused by a combination of reservoir facies pinchout, flooding shale markers, and the faults. Considerable reserve growth potential exists at Budare field because the reservoir units are highly compartment by the depositional heterogeneity and structural complexity. Numerous reserve growth opportunities were identified in attics updip of existing production, in untapped or incompletely drained compartments, and in field extensions.
[Association of sardine fishery, Sardinella aurita (Teleostei: Clupeidae) and environmental variability of the coastal upwelling ecosystem of Nueva Esparta, Venezuela].
Gonzźlez, Leo W; Euán, Jorge; Eslava, Nora; Suniaga, Jesús
The present research is an analysis of Spanish sardine fishing (Sardinella aurita) associated with some climatic and meteorologic parameters of the ecosystem from El Morro Nueva Esparta, Venezuela. The catch and environmental data from the area were taken in the period 1996-2000. Catch data as a function of wind speed, sea surface temperature, air temperature and rain were analyzed by means of simple lineal regression and multiple models. We found a positive correlation of catch with wind speed, and a negative correlation with sea surface temperature, air temperature, and rain. The multiple regression model with intercept had a poor fit, therefore, we made a model without intercept, which improve greatly the fit. A selection of the variables using the forward procedure verified that the independent variables "wind speed" and "air temperature" have a significant relation with catch (p < 0.001) at real time. This method suggests that sea surface temperature and rain have little influence on the catch, and suggests a major availability of resources in the months with low air temperature and the highest wind speed (January-June). Rev. PMID:18457137
[Risk factors associated with the diagnosis of chronic Chagasic miocardiopathy in seropositive individuals from Barinas state, Venezuela].
González, Beatriz; Silva, Martha; Al-Atrache, Yusra; Delgado, Yelitze; Serrano, José Luis; Doccimo, Angelina; Hernández, Huber; Verde, Juan; Morillo, Daniela; Marín, Jaime; Concepción, Juan Luis; Bonfante-Cabarcas, Rafael; Rodríguez-Bonfante, Claudina
This study evaluates the risk factors associated with the diagnosis of chronic chagasic miocardiopathy (CChM) in 115 seropositive individuals to anti-Trypanosoma cruzi antibodies, in Barinas state, Venezuela. Serology was performed with ELISA and MABA; while the CChM diagnosis was established by electrocardiography and echocardiography. A complete clinical history including epidemiological, personal/familiar antecedents and psychobiological habits, plus socioeconomic, psychosocial and alimentary habits interviews were performed for each individual. Risk factors were determined through binary logistic regression. Results showed that 81 patients (70,4%; CI 95% = 66.4-74.4) had criteria for CChM, of which 74 (64.4%; IC 95% = 60.2-68.6) were in phase II; while 34 (29.6%; IC 95% = 25.5-33.5) were in phase I of the disease and 7 (6.1%; IC 95% = 4.0-8.2) in phase III. In a one year period, two patients in phase III died of heart failure. The diagnosis of CChM was associated with hunting practice, maternal history of cardiopathies, chewing chimó, medical history of hypertension and apex beat visible; it was negatively associated with canned and preserved foods ingest. In conclusion the CChM diagnosis has high frequency in seropositive individuals in Barinas and heart failure prevention must be based on an early medical attention and educative strategies in order to control risk factors. PMID:24974628
Mesozoic-Early Paleogene Paleogeography of Venezuela/Trinidad and its implications for Caribbean/South America plate interaction
James, K.H.; Rigby, S.M.
We present paleogeographic reconstruction illustrating Jurassic-Early Cretaceous passive margin development along northern South America, followed by Late Cretaceous-Middle Eocene convergence between the Caribbean and South America plates. The maps support the model of in-situ origin of the Caribbean Plate. To construct the map's information from northern allochthonous units was combined with that from autochthonous units in the south. Allochthons comprise olistostromes, within upper Cretaceous-lower Paleogene flysch deposits, and upper Jurassic-lower Cretaceous metasediments in the Caribbean Mountains. In addition, northward tectonic escape of the Maracaibo Block and shortening resulting from plate collision were restored. The Late Cretaceous-Middle Eocene climax of Caribbean-South America plate collision was coeval from western Venezuela to Trinidad. Shortening juxtaposed rocks of disparate origins. However, the association of oceanic/volcanic elements with shelf deposits shows that the former were related to opening of the Caribbean and development of the Mesozoic passive margin of northern South America rather than originating in the Pacific. Since the late Eocene, plate interaction has been eastward migrating, dextral relative movement.
Evaluation of the Seismic Hazard in Venezuela with a revised seismic catalog that seeks for harmonization along the country borders
NASA Astrophysics Data System (ADS)
Rendon, H.; Alvarado, L.; Paolini, M.; Olbrich, F.; González, J.; Ascanio, W.
Probabilistic Seismic Hazard Assessment is a complex endeavor that relies on the quality of the information that comes from different sources: the seismic catalog, active faults parameters, strain rates, etc. Having this in mind, during the last several months, the FUNVISIS seismic hazard group has been working on a review and update of the local data base that form the basis for a reliable PSHA calculation. In particular, the seismic catalog, which provides the necessary information that allows the evaluation of the critical b-value, which controls how seismic occurrence distributes with magnitude, has received particular attention. The seismic catalog is the result of the effort of several generations of researchers along the years; therefore, the catalog necessarily suffers from the lack of consistency, homogeneity and completeness for all ranges of magnitude over any seismic study area. Merging the FUNVISIS instrumental catalog with the ones obtained from international agencies, we present the work that we have been doing to produce a consistent seismic catalog that covers Venezuela entirely, with seismic events starting from 1910 until 2012, and report the magnitude of completeness for the different periods. Also, we present preliminary results on the Seismic Hazard evaluation that takes into account such instrumental catalog, the historical catalog, updated known fault geometries and its correspondent parameters, and the new seismic sources that have been defined accordingly. Within the spirit of the Global Earthquake Model (GEM), all these efforts look for possible bridges with neighboring countries to establish consistent hazard maps across the borders.
Sawfishes and Other Elasmobranch Assemblages from the Mio-Pliocene of the South Caribbean (Urumaco Sequence, Northwestern Venezuela)
The Urumaco stratigraphic sequence, western Venezuela, preserves a variety of paleoenvironments that include terrestrial, riverine, lacustrine and marine facies. A wide range of fossil vertebrates associated with these facies supports the hypothesis of an estuary in that geographic area connected with a hydrographic system that flowed from western Amazonia up to the Proto-Caribbean Sea during the Miocene. Here the elasmobranch assemblages of the middle Miocene to middle Pliocene section of the Urumaco sequence (Socorro, Urumaco and Codore formations) are described. Based on new findings, we document at least 21 taxa of the Lamniformes, Carcharhiniformes, Myliobatiformes and Rajiformes, and describe a new carcharhiniform species (†Carcharhinus caquetius sp. nov.). Moreover, the Urumaco Formation has a high number of well-preserved fossil Pristis rostra, for which we provide a detailed taxonomic revision, and referral in the context of the global Miocene record of Pristis as well as extant species. Using the habitat preference of the living representatives, we hypothesize that the fossil chondrichthyan assemblages from the Urumaco sequence are evidence for marine shallow waters and estuarine habitats. PMID:26488163
[Larvae-pupae parasitoids of Hylesia metabus Cramer (Lepidoptera: Saturniidae) in northeastern Venezuela: a case of natural biological control].
Hernández, José V; Osborn, Frances; Herrera, Beatriz; Liendo-Barandiaran, Carmen V; Perozo, José; Velásquez, Diony
The moth Hylesia metabus Cramer is considered a public health pest due to the release of urticating hairs by adult females during periodic invasions of towns and villages, producing dermatits in humans. We reported natural parasitism levels for this moth during six life cycles in two localities in northeastern Venezuela. Pupae were collected in the field and maintained under laboratory conditions (27 masculineC, 65% RH, 12L:12D photoperiod) until eclosion. In Mapire, parasitism increased from 33.0% to 91.1% in the three cycles studied, with the dipterans Belvosia spp. (Tachinidae) and Sarcodexia lambens Wiedemann (Sarcophagidae) and species from Ichneumonidae, Chalcidae, Perilampidae and Eulophidae being the most common. In Pedernales, parasitism decreased from 29.5% to 16.1%, and Belvosia spp. was the most abundant parasitoids, reaching parasitization levels between 70.7% and 96.2%. A significative parasitization by Neotheronia sp. (Hymenoptera: Ichneumonidae) (27.1%) occurred only in third life cycle. All natural enemies observed were koinobionts, larval-pupa parasitoids. The variations in the populations of H. metabus and its parasitoids in the areas studied are discussed. Belvosia spp. and S. lambens may have potential for use in integrated management program of H. metabus. PMID:19488514
Effect of Environmental Disturbance on the Population of Sandflies and Leishmania Transmission in an Endemic Area of Venezuela
Nieves, Elsa; Oraá, Luzmary; Rondón, Yorfer; Sánchez, Mireya; Sánchez, Yetsenia; Rojas, Masyelly; Rondón, Maritza; Rujano, Maria; González, Nestor; Cazorla, Dalmiro
The exploitation of new wilderness areas with crops is increasing and traditional crop substitution has been modified by new more productive crops. The results show the anthropogenic disturbance effect on the sandflies population and Leishmania transmission in endemic areas of Venezuela. Three agroecosystems with variable degrees of ecological disturbance, forest (conserved), cacao (fragmented), and orangery (disturbed), were selected. Four methods to sandfly capture were used; the specimens were identified and infected with Leishmania. Diversity, population structure, ANOVA, Tukey test, and simple correlation analysis were carried out. Shannon traps were able to capture 94.7% of the total sandflies, while CDC light traps, Sticky traps, and direct suction just captured 2.2%, 1.2%, and 0.9%, respectively. The results showed the effect of ecological disturbance degree on the composition of sandflies and population structure, revealing a dominance level increased but decreased on the diversity and richness of sandflies species in the greatest ecological disturbance area in relation to areas with less organic disturbance. Environments more disturbed cause adaptability of certain species such as Lutzomyia gomezi and Lutzomyia walkeri. These changes on the composition of sandflies population and structure emerging species could cause increasing of leishmaniasis transmission. PMID:24949018
A new Dasypodini armadillo (Xenarthra: Cingulata) from San Gregorio Formation, Pliocene of Venezuela: affinities and biogeographic interpretations.
Castro, Mariela C; Carlini, Alfredo A; Sánchez, Rodolfo; Sánchez-Villagra, Marcelo R
We describe Pliodasypus vergelianus gen. et sp. nov., a Dasypodini armadillo from the middle Pliocene of Venezuela (Vergel Member, San Gregorio Formation). Although scarce, the remains are remarkable because of their geochronologic proximity to the main phase of Great American Biotic Interchange (GABI). The cladistic analysis conducted reveals that Pliodasypus groups with Dasypus and both are sister taxa of Propraopus, whereas Anadasypus is at a basal position. With respect to the records of tribe Dasypodini, after its oldest representative (Anadasypus, middle and late Miocene), the chronologically subsequent form is Pl. vergelianus (middle Pliocene), followed by Dasypus bellus in higher northern latitudes (late Pliocene), and then by widespread occurrences in the Pleistocene of North America (D. bellus) and South America (Propraopus, Dasypus punctatus, and Dasypus novemcinctus). Thus, we infer that Dasypus differentiated in the late Pliocene at low latitudes in the northern South America. It leads to two alternative hypotheses of dispersal: (a) some early Dasypus remained cryptically in South America until the Pleistocene, whereas others dispersed to North America between 2.2 and 2.7 Ma, or (b) they dispersed to North America subsequently to the emersion of the Panamanian isthmus and D. bellus differentiated there; later, during the Pleistocene, D. bellus entered South America and experienced speciation. The same process of re-ingression has been proposed to other xenarthrans, breaking with the traditional assumption that the GABI was unidirectional. PMID:24414134
Dynamics of Black Band Disease in a Diploria strigosa population subjected to annual upwelling on the northeastern coast of Venezuela
NASA Astrophysics Data System (ADS)
Rodríguez, S.; Cróquer, A.
Temporal variability of Black Band Disease (BBD) prevalence, incidence, recurrence, recovery and virulence was estimated in a Diploria strigosa population from an upwelling zone of Venezuela, for 1 year between August 2004 and August 2005. The sampling spanned both upwelling and non-upwelling seasons, and included three samplings, roughly 60 days apart, within each season. The negative effects of BBD epizootiology in the sampling population (El Mercado reef) were positively correlated with sea surface temperature (taken as an upwelling estimator). Disease prevalence, incidence and recurrence decreased significantly during upwelling, and the recovery rate increased. Contrary to expectations, tissue mortality did not decrease significantly during the upwelling season, remaining at 1.2 ± 0.7 mm day-1. BBD prevalence, and the ensuing rates of tissue mortality were higher than values previously reported for other Caribbean reefs, even during upwelling episodes, suggesting that nutrient enrichment of the local waters by upwelling counteracts the expected reductions of the disease prevalence and virulence due to the lower temperature. Colonies which had previously been infected with BBD were up to six times more susceptible to new infections than those which were not infected during the preceding 7 months, suggesting that the infected colonies never healed completely. The high variability between tissue mortality values among coral colonies also suggests that overall host health-status may alter susceptibility to BBD infections.
Tomato chlorotic leaf distortion virus, a new bipartite begomovirus infecting Solanum lycopersicum and Capsicum chinense in Venezuela.
Zambrano, Karla; Geraud-Pouey, Francis; Chirinos, Doris; Romay, Gustavo; Marys, Edgloris
Virus isolate T217L was obtained from a diseased tomato (Solanum lycopersicum) plant showing leaf deformation and chlorotic mottle symptoms near Maracaibo in the state of Zulia, Venezuela. Full-length DNA-A and DNA-B molecules of T217L were cloned and sequenced. The genome organization of T217L was identical to the bipartite genomes of other begomoviruses described from the Americas. Characteristic disease symptoms were reproduced in S. lycopersicum and Capsicum annum plants inoculated using the cloned viral DNA-A and DNA-B components, confirming disease aetiology. A sequence analysis of DNA-A showed that the T217L isolate has the highest sequence identity (84%) with sida yellow mosaic Yucatan virus (SiYMYuV), sida golden mosaic Honduras virus (SiGMHV) and bean dwarf mosaic virus (BDMV) isolates. This is less than the 89% identity in the DNA-A component that has been defined as the threshold value for the demarcation of species in the genus Begomovirus. The molecular data show that isolate T217L belongs to a novel tentative begomovirus species, for which the name tomato chlorotic leaf distortion virus is proposed. TCLDV was also detected in symptomatic C. chinense plants growing near the T217L-infected plant. PMID:21853328
Reassessing the cultural and psychopharmacological significance of Banisteriopsis caapi: preparation, classification and use among the Piaroa of Southern Venezuela.
Rodd, Robin
Recent attention to the monoamine oxidase inhibiting properties of Banisteriopsis caapi's harmala alkaloids has precluded a balanced assessment of B. caapi's overall significance to indigenous South American societies. Relatively little attention has been paid to the cultural contexts, local meanings and patterns of use of B. caapi among snuff-using societies, such as the Piaroa, who do not prepare decoctions containing N,N-dimethyltryptamine (DMT) admixtures. This article reviews the psychopharmacological literature on B. caapi in light of recent ethnographic work conducted among the Piaroa of southern Venezuela. Piaroa shamans use only B. caapi's cambium, identify at least five distinct varieties of B. caapi, and emphasise the plant's importance for heightening empathy. Some Piaroa people also attribute a range of extra-shamanic uses to B. caapi, including as a stimulant and hunting aid. In light of the psychopharmacological complexity of harmala alkaloids, and ethnographic evidence for a wide range of B. caapi uses,future research should reconsider B. caapi's cultural heritage and psychopharmacological potential as a stimulant and antidepressant-like substance. PMID:19004422
The relationship between mud volcanoes, petroleum migration and accretionary prisms: Lessons from the Caucasus, the Australian margin and Venezuela
Ware, P.
Mud volcanoes have been widely documented in areas of overpressure where explosive expansion of trapped methane has occurred during argillokinesis. In an area with high sedimentation rate, such as the Gulf of Mexico, there may be no time for fine-grained sediment to de-water before being covered by impermeable material. In an accretionary wedge this process is complicated by overthrusting of off-scraped material which increases the overburden pressure and provides many more avenues for the migration of fluids through the system. In some cases, such as is seen in the Caribbean, the fluids may escape directly to the surface (or seabottom) through high permeability beds. When this happens there may be no diapirism. In other cases, such as in Venezuela, the forearc may be the site of rapid, laterally-derived, sedimentation, and fluids from the overthrusted rocks may be forced to escape through several kilometers of recent deltaic sediments. Since these fluids may include petroleum, this has obvious exploration potential. If there are no suitable reservoir rocks, such as in Timor, there may be no commercial accumulations. However, many giant fields are associated, world-wide, with mud volcanoes, such as those in Azerbaijan.
Debris-flow and flooding deposits in coastal Venezuela associated with the storm of December 14-16, 1999
Wieczorek, Gerald F.; Larsen, Matthew C.; Eaton, L. Scott; Morgan, Benjamin A.; Blair, J. Luke
Heavy rainfall from the storm of December 14?16, 1999, triggered thousands of shallow landslides on steep slopes of the Sierra de Avila north of Caracas, Venezuela, and caused flooding and massive debris flows in the channels of major drainages that severely damaged coastal communities along the Caribbean Sea. Within this region we characterized geologic conditions where landslides initiated on hillsides and examined the texture of debris-flow deposits in the channels of nine drainages. In one of the most severely damaged areas on a highly developed alluvial fan at Caraballeda, we measured debris-flow deposits that ranged up to 5 meters (m) in thickness, inundating structures and roads over a large portion of the fan. Boulders up to 5 m long were carried along by the flows, impacted structures causing serious damage, and were deposited on the fan. Using field measurements and comparing pre-event and post-event topography from aerial photographs, we determined the volume of debris-flow and flood deposition on the fan to be about 2 million cubic meters. The total volume of material transported and deposited by landslides throughout the Vargas region ranks this as one of the most severe historical erosional events worldwide.
First description of the breeding biology and natural history of the ochre-breasted brush finch atlapetes semirufus in venezuela
Biancucci, L.; Martin, T.E.
We provide the first description of the eggs, breeding biology, and natural history of the Ochre-breasted Brush Finch (Atlapetes semirufus). We found 37 nests over four breeding seasons (2004-2007) in Yacamb?? National Park, Venezuela. Nesting activity started in late April and continued until early June suggesting single-brooded behavior despite a typical tropical clutch size of two eggs (x?? = 1.89) that were laid on consecutive days. Egg mass averaged 3.38 g and 11.6% of adult female mass. The incubation and nestling periods averaged 14.9 and 10.5 days, respectively. Only females incubated and the percent time they spent incubating did not change between early and late incubation. Females brooded 42.7% of the time when nestlings were 2 days of age and 20.5% when 9 days of age. Both parents provisioned young at a low rate (3.9 trips/hr) and nestling growth rate (k = 0.45) was also slow. Nest predation rates were relatively high with daily mortality rates of 0.058 and 0.067 during incubation and nestling stages, respectively.
A new Dasypodini armadillo (Xenarthra: Cingulata) from San Gregorio Formation, Pliocene of Venezuela: affinities and biogeographic interpretations
NASA Astrophysics Data System (ADS)
Castro, Mariela C.; Carlini, Alfredo A.; Sánchez, Rodolfo; Sánchez-Villagra, Marcelo R.
We describe Pliodasypus vergelianus gen. et sp. nov., a Dasypodini armadillo from the middle Pliocene of Venezuela (Vergel Member, San Gregorio Formation). Although scarce, the remains are remarkable because of their geochronologic proximity to the main phase of Great American Biotic Interchange (GABI). The cladistic analysis conducted reveals that Pliodasypus groups with Dasypus and both are sister taxa of Propraopus, whereas Anadasypus is at a basal position. With respect to the records of tribe Dasypodini, after its oldest representative ( Anadasypus, middle and late Miocene), the chronologically subsequent form is Pl. vergelianus (middle Pliocene), followed by Dasypus bellus in higher northern latitudes (late Pliocene), and then by widespread occurrences in the Pleistocene of North America ( D. bellus) and South America ( Propraopus, Dasypus punctatus, and Dasypus novemcinctus). Thus, we infer that Dasypus differentiated in the late Pliocene at low latitudes in the northern South America. It leads to two alternative hypotheses of dispersal: (a) some early Dasypus remained cryptically in South America until the Pleistocene, whereas others dispersed to North America between 2.2 and 2.7 Ma, or (b) they dispersed to North America subsequently to the emersion of the Panamanian isthmus and D. bellus differentiated there; later, during the Pleistocene, D. bellus entered South America and experienced speciation. The same process of re-ingression has been proposed to other xenarthrans, breaking with the traditional assumption that the GABI was unidirectional.
Breeding biology of the Three-striped warbler in Venezuela: A contrast between tropical and temperate parulids
Cox, W.A.; Martin, T.E.
We document reproductive life history traits of the Three-striped Warbler (Basileuterus tristriatus) from 146 nests in Venezuela and compare our results to data from the literature for other tropical and temperate parulid species. Mean (?? SE) clutch size was 1.96 ?? 0.03 eggs (n = 96) and fresh egg mass was 2.09 ?? 0.02 g. The incubation period was 15.8 ?? 0.2 days (n = 23) and the nestling period was 10.5 ?? 0.3 days (n = 12). Males did not incubate and rarely provided food for females during incubation. Females had 57 ?? 2% (n = 49) nest attentiveness (% of time on the nest incubating), which caused egg temperature to commonly become cold relative to development. Both adults fed nestlings and feeding rates increased with nestling age. The growth rate constant for nestlings based on mass was K 0.490, which is slower than for north temperate warblers. Predation was the primary source of nest failure and only 22% of nests were successful based on a Mayfield daily predation rate of 0.048 ?? 0.006. Our literature review indicates parulids differ strongly in life histories between temperate and tropical/subtropical sites with species in the tropics having, on average, smaller clutches, longer incubation periods, lower nest attentiveness, longer off-bouts, and longer nestling periods. ?? 2009 by the Wilson Ornithological Society.
Reproductive biology of the violet-chested hummingbird in Venezuela and comparisons with other tropical and temperate hummingbirds
Fierro-Calderon, K.; Martin, T.E.
We provide details on the breeding biology of the Violet-chested Hummingbird (Sternoclyta cyanopectus) based on 67 nests studied in Yacambu?? National Park, Venezuela, from 2002 through 2006. Clutch size was two white eggs, usually laid every other day. Fresh egg mass (0.95 ?? 0.14 g) was 15% of female mass. Incubation and nestling periods were 20.4 ?? 0.3 and 26.0 ?? 0.4 days, respectively. Nest attentiveness increased from 60% in early incubation to 68% in late incubation. The female spent 50% of her time brooding young nestlings, but ceased brooding by 13 days of age. Only the female fed the young, with a low rate of nest visitation (3.3 trips per hour) that did not increase with age of the young. Growth rate based on nestling mass (K = 0.28) was slow. Daily predation rates decreased across stages and were 0.064 ?? 0.044, 0.033 ?? 0.008, and 0.020 ?? 0.006 during the egg-laying, incubation, and nestling periods, respectively. Most, but not all, life history traits of the Violet-chested Hummingbird were similar to those reported for other tropical and temperate hummingbirds, providing further evidence that this family shows a relatively narrow range of life history variation. ?? The Cooper Ornithological Society 2007.
Venezuela-MEM/USA-DOE Fossil Energy Report XIII-1, Supporting Technology for Enhanced Oil Recovery, Microbial EOR
Ziritt, Jose Luis
The results from Annex XIII of the Cooperative Agreement between the United States Department of Energy (DOE) and the Ministry of Energy and Mines of the Republic of Venezuela (MEMV) have been documented and published with many researchers involved. Integrate comprehensive research programs in the area of Microbial Enhanced Oil Recovery (MEOR) ranged from feasibility laboratory studies to full-scale multi-well field pilots. The objective, to cooperate in a technical exchange of ideas and information was fully met throughout the life of the Annex. Information has been exchanged between the two countries through published reports and technical meetings between experts in both country's research communities. The meetings occurred every two years in locations coincident with the International MEOR conferences & workshops sponsored by DOE (June 1990, University of Oklahoma, September 1992, Brookhaven, September 1995, National Institute of Petroleum and Energy Research). Reports and publications produced during these years are listed in Appendix B. Several Annex managers have guided the exchange through the years. They included Luis Vierma, Jose Luis Zirritt, representing MEMV and E. B. Nuckols, Edith Allison, and Rhonda Lindsey, representing the U.S. DOE. Funding for this area of research remained steady for a few years but decreased in recent years. Because both countries have reduced research programs in this area, future exchanges on this topic will occur through ANNEX XV. Informal networks established between researchers through the years should continue to function between individuals in the two countries.
Evaluating oil quality and monitoring production from heavy oil reservoirs using geochemical methods: Application to the Boscan Field, Venezuela
Kaufman, R.L.; Noguera, V.H.; Bantz, D.M.; Rodriguez, R.
Many oil fields worldwide contain heavy oil in one or more reservoir units. The low gravity of these oils is most frequently due to biodegradation and/or low maturity. The challenge is to find ways to economically recover this oil. Methods which reduce the operating costs of producing heavy oil add significant value to such projects. Geochemical techniques which use the composition of the reservoir fluids as natural tracers offer cost effective methods to assist with reservoir management. The low viscosity and gravity of heavy oil, combined with frequent high water cuts, low flow rates, and the presence of downhole artificial lift equipment, make many conventional production logging methods difficult to apply. Therefore, monitoring production, especially if the produced oil is commingled from multiple reservoirs, can be difficult. Geochemical methods can be used to identify oil/water contacts, tubing string leaks and to allocate production to individual zones from commingled production. An example of a giant heavy oil field where geochemical methods may be applicable is the Boscan Field in Venezuela. Low maturity oil, averaging 10{degrees} API gravity, is produced from the Eocene Upper and Lower Boscan (Miosa) Sands. Geochemical, stratigraphic and engineering data have helped to better define the controls on oil quality within the field, identified new reservoir compartments and defined unique characteristics of the Upper and Lower Boscan oils. This information can be used to identify existing wells in need of workovers due to mechanical problems and to monitor production from new infill wells.
[The phorophyte occupation patterns by vascular epiphyte species in the High Orinoco tropical humid forest, Amazonas State, Venezuela].
Hernández-Rosas, J
By international agreement (Austria-Venezuela), an experimental area was selected for canopy ecology studies. A tower crane was installed that allows direct access to the canopy of 1.5 ha area of the forest. This is a quantitative study of the phorophyte occupation patterns by vascular epiphyte species in an Amazon tropical humid forest. The forest of Surumoni consists roughly of four arboreal strata, i.e., emergent (conspicuous), superior, middle and lower. The largest proportion of trees occurs in the lower diametric classes (smaller DBH), and the total distribution approaches an "inverted J" curve. The most abundant tree species in the three strata is Goupia glabra (Celastraceae); making this forest a case where a single arboreal species dominants. Mean of epiphyte individuals per occupied phorophyte is too variable, depending on phorophyte species and showing no correlation with occupied tree percentage. The species Eschweleira parviflora (Lecythidaceae) represented in the study area by a single individual of the superior stratum with high density of vascular epiphytes, indicates that this support species is particularly favorable for the establishment epiphytic flora. PMID:11915448
[Nitrogen, phosphorus and the C/N ratio in superficial sediments of the lagoon of Chacopata, Sucre, Venezuela].
Fuentes Hernández, M V
The basal behaviour and relationship with organic carbon (Corg) content and prevailing granulometric fractions, of organic nitrogen (Norg), total phosphorus (P-total) and C/N ratio in surface sediments of Chacopata lagoon, Sucre State, Venezuela, were studied. Concentrations and spatial gradients were determined in sixteen stations following a common method for marine sediments. Norg concentrations varied between 0.102 and 0.510% (x = 0.237%), total phosphorus between 0.012 and 0.094% (x = 0.058%) and C/N ratio between 9.27 and 44.47 (x = 20.53). The higher contents of Norg and total phosphorus are from sections with an abundance of mangroves, marine phanerogams, macroalgae, benthonic biomass and migratory birds shelters. The C/N ratio shows the typical values for carbonated sediments, indicating that the nitrogenous compounds are rapidly degraded and the organic matter presents itself as humic substances. This parameter was moderately associated with silt and clay, and showed antagonism with sand, whereas Norg and phosphorus showed no correlation with them. The organic contribution is purely autochthonous: no anthropogenous contributions were found. PMID:15266816
Aerosol particle properties in the tropical free troposphere observed at Pico Espejo (4765 m a.s.l.), Venezuela
NASA Astrophysics Data System (ADS)
Schmeißner, T.; Krejci, R.; Ström, J.; Birmili, W.; Wiedensohler, A.; Hochschild, G.; Gross, J.; Hoffmann, P.; Calderon, S.
The first long-term measurements of aerosol number and size distributions in South-American tropical free troposphere were performed from March 2007 until Mai 2009. The measurements took place at the high altitude Atmospheric Research Station Alexander von Humboldt. The station is located on top of the Sierra Nevada mountain ridge at 4765 m a.s.l. nearby the city of Mérida, Venezuela. Aerosol size distribution and number concentration data was obtained with a custom-built Differential Mobility Particle Sizer (DMPS system) and a Condensational Particle Counter (CPC). The analysis of the annual and diurnal variability of the tropical free troposphere (FT) aerosol focused mainly on possible links to the atmospheric general circulation in the tropics. Considerable annual and diurnal cycles of the particle number concentration were observed. Highest total particle number concentrations were measured during the dry season (519±613 cm-3), lowest during the wet season (318±194 cm-3). The more humid FT contained generally higher aerosol particle number concentrations (573±768 cm-3 during dry season, 320±195 cm-3 during wet season) than the dry FT (454±332 cm-3 during dry season, 275±172 cm-3 during wet season), indicating the importance of convection for aerosol distributions in the tropical FT. The diurnal cycle in the variability of the particle number concentration was mainly driven by local orography.
Spur cell anaemia and acute haemolysis in patients with hyperreactive malarious splenomegaly. Experience in an isolated Yanomamo population of Venezuela.
Torres R, J R; Magris, M; Villegas, L; Torres V, M A; Dominguez, G
A prospective study, aimed to investigate the aetiology of an unusual clustering of cases of severe acute haemolytic anaemia affecting a high percentage of the adult population, was carried out in two isolated Yanomamo communities of the Upper Orinoco basin in Venezuela. Twenty-six patients with active or recent episodes of severe haemolysis were evaluated. All of them exhibited massive liver and spleen enlargement and fulfilled the diagnostic criteria of the hyperreactive malarious splenomegaly (HMS) syndrome. In four cases with advanced non-alcohol-related chronic liver disease, hypersplenism, severe haemolytic anaemia and acanthocytosis, the characteristic clinical and laboratory findings of spur cell anaemia were documented. Chronic infection by the HBV and HCV was present in three of them. However, in most of the 22 additional HMS cases, the acute haemolytic condition appeared associated with the occurrence of a cold agglutinin-mediated autoimmune response. The clustering of a significant number of cases of severe acute haemolysis in HMS patients from this small isolated aboriginal community is most unusual, and represents a serious complicating factor for a population already beleaguered by a high prevalence of malaria due to multiresistant strains of Plasmodium falciparum. Moreover, the coexistence of HMS and severe chronic HBV or HCV infection may further aggravate the course of the haemolytic disorder, because of the occurrence of spur cell anaemia. PMID:11114387
Potential of vetiver (vetiveria zizanioides (L.) Nash) for phytoremediation of petroleum hydrocarbon-contaminated soils in Venezuela.
Brandt, Regine; Merkl, Nicole; Schultze-Kraft, Rainer; Infante, Carmen; Broll, Gabriele
Venezuela is one of the largest oil producers in the world. For the rehabilitation of oil-contaminated sites, phytoremediation represents a promising technology whereby plants are used to enhance biodegradation processes in soil. A greenhouse study was conducted to determine the tolerance of vetiver (Vetiveria zizanioides (L.) Nash) to a Venezuelan heavy crude oil in soil. Additionally, the plant's potential for stimulating the biodegradation processes of petroleum hydrocarbons was tested under the application of two fertilizer levels. In the presence of contaminants, biomass and plant height were significantly reduced. As for fertilization, the lower fertilizer level led to higher biomass production. The specific root surface area was reduced under the effects of petroleum. However, vetiver was found to tolerate crude-oil contamination in a concentration of 5% (w/w). Concerning total oil and grease content in soil, no significant decrease under the influence of vetiver was detected when compared to the unplanted control. Thus, there was no evidence of vetiver enhancing the biodegradation of crude oil in soil under the conditions of this trial. However, uses of vetiver grass in relation to petroleum-contaminated soils are promising for amelioration of slightly polluted sites, to allow other species to get established and for erosion control. PMID:17305302
[Enterobius vermicularis in preschool children from a suburban area in San Félix, Bolívar State, Venezuela].
Requena, Ixora; Jiménez, Yolimar; Rodríguez, Natacha; Sandoval, Maria; Alcala, Frannegy; Blanco, Ytalia; Devera, Rodolfo
To determine the enterobiosis prevalence in preschool children, a study was carried out from may-july 2003, in the SEU "Teresa de la Parra" in San Félix, Bolívar State, Venezuela. Three samples from the perianal region were obtained from every child, by applying the Graham method, and one sample was obtained of the subungucal deposit by scraping and cutting off their finger nails. These samples were preserved in 10% formol and processed by the formol-ether method. Also, a stool sample was collected and analyzed by direct examination and the formol-ether method. The prevalence of Enterobius vermicularis was 45.8% (27/59). No differences in relation to age (chi2 = 1.23 d. f. = 2) and sex (p > 0.05) were observed between the infected children. The eggs E. vermicularis were not observed in the 59 samples of subungueal deposits. In conclusion, although the enterobiosis prevalence was high, as determined by the Graham method, a relationship could not be found between E. vermicularis in the scotch tape and the finger nail samples of the children evaluated. PMID:17853787
Sawfishes and Other Elasmobranch Assemblages from the Mio-Pliocene of the South Caribbean (Urumaco Sequence, Northwestern Venezuela).
Carrillo-Briceño, Jorge D; Maxwell, Erin; Aguilera, Orangel A; Sánchez, Rodolfo; Sánchez-Villagra, Marcelo R
The Urumaco stratigraphic sequence, western Venezuela, preserves a variety of paleoenvironments that include terrestrial, riverine, lacustrine and marine facies. A wide range of fossil vertebrates associated with these facies supports the hypothesis of an estuary in that geographic area connected with a hydrographic system that flowed from western Amazonia up to the Proto-Caribbean Sea during the Miocene. Here the elasmobranch assemblages of the middle Miocene to middle Pliocene section of the Urumaco sequence (Socorro, Urumaco and Codore formations) are described. Based on new findings, we document at least 21 taxa of the Lamniformes, Carcharhiniformes, Myliobatiformes and Rajiformes, and describe a new carcharhiniform species (†Carcharhinus caquetius sp. nov.). Moreover, the Urumaco Formation has a high number of well-preserved fossil Pristis rostra, for which we provide a detailed taxonomic revision, and referral in the context of the global Miocene record of Pristis as well as extant species. Using the habitat preference of the living representatives, we hypothesize that the fossil chondrichthyan assemblages from the Urumaco sequence are evidence for marine shallow waters and estuarine habitats. PMID:26488163
Simulation of patella alta and the implications for in vitro patellar tracking in the ovine stifle joint.
Bertollo, Nicky; Pelletier, Matthew H; Walsh, William R
Patella alta is associated with adverse cartilage adaptations, patellofemoral pain, and instability. It is defined by a relatively long patellar tendon and patella positioned in a more proximal location within the patellar groove of the femur. This study used the ovine stifle joint model to investigate the effect of patellar tendon lengthening on the 3D passive kinematics of the patellofemoral and tibiofemoral joints. Eight patellar tendons were lengthened in 2 mm increments up to a maximum of 12 mm (20%) using a device placed in series with the transected patellar tendon. Three-dimensional kinematics were measured in the intact joint and at each increment of patellar tendon length (L(T)) during passively induced tibiofemoral flexion. Patellar flexion angle was linearly correlated with tibial flexion angle in the intact joint, and this correlation persisted after tendon lengthening (R = 0.897-0.965, p < 0.01). Patellofemoral kinematics expressed as a function of tibial flexion angle were significantly altered by L(T) increases >9%. In contrast, when patellofemoral kinematics were expressed as a function of patellar flexion angle they were not significantly altered by increases in L(T). Tibiofemoral kinematics were not affected by the L(T) increases. These results demonstrate that for a given tibial flexion angle, patellar tendon lengthening alters the patellar flexion angle. However, for a given patellar flexion angle, the orientation of the patella in the remaining five degrees of freedom is unchanged, implying a repeatable path of patellar motion. PMID:22581606
New Records of Mosquitoes (Diptera: Culicidae) from Bolívar State in South Eastern Venezuela, with 27 New Species for the State and 5 of Them New in the Country
Berti, Jesús; Guzmán, Hernán; Estrada, Yarys; Ramírez, Rodrigo
This is the first part of a series of studies related to mosquito ecological and biogeographic aspects. A total of 69 mosquito species (Diptera: Culicidae) was collected in 16 localities sampled in the Gran Sabana Municipality, Canaima National Park, and Venezuela. Twenty-seven mosquito species are recorded for the first time from Bolívar State, Venezuela. Five of them species are reported for the first time in Venezuela: Anopheles malefactor Dyar and Knab (1907); Chagasia bonneae Root (1927); Chagasia ablusa Harbach (2009); Culex anduzei Lane (1944), and Uranotaenia leucoptera Theobald (1907). Their medical importance is commented, and ecological and epidemiological aspects are discussed. A checklist of the mosquito species reported in the Gran Sabana County is given. PMID:25853113
Descripción de la zona de alta difusión en un modelo bidimensional para hojas de corriente
NASA Astrophysics Data System (ADS)
Montero, M. F.; Paola, C. A.; Platzeck, A. M.
Los modelos bidimensionales para describir hojas de corriente de alta simetría no suministran una descripción detallada de las regiones donde la difusión es considerablemente importante. Tal es el caso de los modelos desarrollados en la década del '60 por Sweet, Parker, Petschek y Sonnerup. En esta comunicación presentamos una solución de las ecuaciones MHD en el entorno del origen, construyendo series bidimensionales para todas las magnitudes físicas involucradas. Valiéndonos de la alta simetría y de las características del problema, logramos reducir el número de coeficientes a calcular. Utilizamos un programa autoconsistente para extender el cálculo a regiones vecinas con difusión moderada o despreciable.
Multiple Paternity in a Reintroduced Population of the Orinoco Crocodile (Crocodylus intermedius) at the El Frío Biological Station, Venezuela.
Rossi Lafferriere, Natalia A; Antelo, Rafael; Alda, Fernando; Mårtensson, Dick; Hailer, Frank; Castroviejo-Fisher, Santiago; Ayarzagüena, José; Ginsberg, Joshua R; Castroviejo, Javier; Doadrio, Ignacio; Vilá, Carles; Amato, George
The success of a reintroduction program is determined by the ability of individuals to reproduce and thrive. Hence, an understanding of the mating system and breeding strategies of reintroduced species can be critical to the success, evaluation and effective management of reintroduction programs. As one of the most threatened crocodile species in the world, the Orinoco crocodile (Crocodylus intermedius) has been reduced to only a few wild populations in the Llanos of Venezuela and Colombia. One of these populations was founded by reintroduction at Caño Macanillal and La Ramera lagoon within the El Frío Biological Station, Venezuela. Twenty egg clutches of C. intermedius were collected at the El Frío Biological Station for incubation in the lab and release of juveniles after one year. Analyzing 17 polymorphic microsatellite loci from 335 hatchlings we found multiple paternity in C. intermedius, with half of the 20 clutches fathered by two or three males. Sixteen mothers and 14 fathers were inferred by reconstruction of multilocus parental genotypes. Our findings showed skewed paternal contributions to multiple-sired clutches in four of the clutches (40%), leading to an overall unequal contribution of offspring among fathers with six of the 14 inferred males fathering 90% of the total offspring, and three of those six males fathering more than 70% of the total offspring. Our results provide the first evidence of multiple paternity occurring in the Orinoco crocodile and confirm the success of reintroduction efforts of this critically endangered species in the El Frío Biological Station, Venezuela. PMID:26982578
Multiple Paternity in a Reintroduced Population of the Orinoco Crocodile (Crocodylus intermedius) at the El Frío Biological Station, Venezuela
Alda, Fernando; Mårtensson, Dick; Hailer, Frank; Castroviejo-Fisher, Santiago; Ginsberg, Joshua R.; Castroviejo, Javier; Doadrio, Ignacio; Vilá, Carles; Amato, George
The success of a reintroduction program is determined by the ability of individuals to reproduce and thrive. Hence, an understanding of the mating system and breeding strategies of reintroduced species can be critical to the success, evaluation and effective management of reintroduction programs. As one of the most threatened crocodile species in the world, the Orinoco crocodile (Crocodylus intermedius) has been reduced to only a few wild populations in the Llanos of Venezuela and Colombia. One of these populations was founded by reintroduction at Caño Macanillal and La Ramera lagoon within the El Frío Biological Station, Venezuela. Twenty egg clutches of C. intermedius were collected at the El Frío Biological Station for incubation in the lab and release of juveniles after one year. Analyzing 17 polymorphic microsatellite loci from 335 hatchlings we found multiple paternity in C. intermedius, with half of the 20 clutches fathered by two or three males. Sixteen mothers and 14 fathers were inferred by reconstruction of multilocus parental genotypes. Our findings showed skewed paternal contributions to multiple-sired clutches in four of the clutches (40%), leading to an overall unequal contribution of offspring among fathers with six of the 14 inferred males fathering 90% of the total offspring, and three of those six males fathering more than 70% of the total offspring. Our results provide the first evidence of multiple paternity occurring in the Orinoco crocodile and confirm the success of reintroduction efforts of this critically endangered species in the El Frío Biological Station, Venezuela. PMID:26982578
A new species of hermit crab of the genus Pagurus Fabricius, 1775 (Crustacea: Anomura: Paguridae) from the southern Caribbean off Venezuela.
Lima, Daniel José Marcondes; Lemaitre, Rafael
A male specimen of a new species of the heterogeneous genus Pagurus Fabricius, 1775, collected in 1968 off the Caribbean coast of Venezuela, was discovered among the vast crustacean collections of the Smithsonian Institution. This new species herein described and illustrated is named P. scopaopsis, and is characterized primarily by the presence of: a brush-like setation pattern on the dactyl of the left third pereopod, dense small tubercles on the dorsal surfaces of the dactyl and fixed finger of the right chela, and a raised longitudinal ridge armed with spines on the palm and fixed finger of the left chela. PMID:27615944
Monitoring of Land Deformation Due to Oil Production by InSAR Time Series Analysis Using PALSAR Data in Bolivarian Republic of Venezuela
NASA Astrophysics Data System (ADS)
Deguchi, Tomonori; Narita, Tatsuhiko
The target area of this study is the Maracaibo sedimentary basin located in the western part of Bolivarian Republic of Venezuela. The full-scale exploration and development for oil resources in Venezuela which was the greatest oil-producing country in South America had begun at the Maracaibo sedimentary basin in the 1910s, and it was a center of the oil product in Venezuela until the 1980s. But, in most of oil fields in the Maracaibo sedimentary basin, there is concern over the drain on recoverable reserves due to deterioration, and the production amount of petroleum in Venezuela has been diminishing these days. Leveling and GPS surveying were carried out in the past, and they revealed that the large-scale subsidence phenomenon of which cumulative subsidence amount was approximately 5 meter had occurred. The authors applied the vertical displacement measurement by InSAR time series analysis using PALSAR data obtained in the Fine-beam and ScanSAR observation mode. As a result, it could be confirmed clear ground deformation in the surrounding of three oil fields (Tia Juana, Lagunillas and Bachaquero) and easily recognized that the areas of phase anomalies detected by this analysis had expanded and the number of interference fringes had increased over time. The annual velocity of vertical ground surface displacement measured by InSAR time series analysis was -51 mm per year, -103 mm per year and -58 mm per year in Tia Juana, Lagunillas and Bachaquero oil field respectively. The tendency that an earth surface shifted towards the center of phase anomalies was detected from the result of the horizontal ground change measurement. It was interpreted from Google Earth and Landsat images that oil-related facilities (mainly bowling stations) were built intensively over the areas where phase anomalies were detected. Therefore, it was inferred that there was a high association between the operation activity of the oil field and ground deformation. In addition, the deterioration
"Muy poco se sabe de los resultados": Francis E. Bond's expedition to the Paria Peninsula and delta of the Orinoco, Venezuela (1911).
Dorr, L J
The natural history expedition of the American banker and stock broker Francis E. Bond and companions to the Paria Peninsula and delta of the Orinoco, Venezuela, in early 1911 is described. Biographical details are provided for the three principles: Francis E. Bond, Stewardson Brown and Thomas S. Gillin. The itinerary of their three and a half month expedition is elaborated, and notes are provided on the collection of plants, animals, and artefacts that they gathered in South America and deposited in the Academy of Natural Sciences of Philadelphia on their return. PMID:21137585
A new baseline for fascioliasis in Venezuela: lymnaeid vectors ascertained by DNA sequencing and analysis of their relationships with human and animal infection
Background Human and animal fascioliasis poses serious public health problems in South America. In Venezuela, livestock infection represents an important veterinary problem whereas there appear to be few human cases reported, most of which are passively detected in health centres. However, results of recent surveys suggest that the situation may be underestimated in particular areas. To obtain a baseline for future fascioliasis assessment, studies were undertaken by means of rDNA ITS-2 and ITS-1 and mtDNA cox1 sequencing to clarify the specific status of Venezuelan lymnaeids, their geographical distribution and fascioliasis transmission capacity, by comparison with other American countries and other continents. Results Results obtained completely change the lymnaeid scenario known so far. The relatively rich lymnaeid fauna of Venezuela has been proven to include (i) Lymnaea meridensis and L. neotropica as the only native members, (ii) L. cubensis and Pseudosuccinea columella introduced from the Caribbean area, and (iii) Galba truncatula and L. schirazensis introduced from the Old World. The absence of representatives of the stagnicoline and Radix groups is remarkable. Four species are fascioliasis vectors: G. truncatula, L. cubensis and L. neotropica, which have the capacity to give rise to human endemic areas, and P. columella, which is a source of animal infection and is responsible for the spread of disease. Vector capacity in the apparently highland endemic L. meridensis is to be confimed, although may be expected given its phylogenetic relationships. Similarly as elsewhere, the non-transmitting L. schirazensis has been confused with L. cubensis, also with G. truncatula and possibly with L. neotropica. Conclusions The new scenario leads to the re-opening of many disease aspects. In Venezuela, altitude appears to be the main factor influencing fascioliasis distribution. Human infection shows an altitude pattern similar to other Andean countries, although a
[Description of an acidic peptidase, insensitive to classical inhibitors, in protein extracts of Trypanosoma cruzi, from a rural area of Venezuela, where Chagas disease is endemic].
Zambrano, Edgar Armando; de la Cruz, Henry Samuel; Coita, Blanca Elena
Through two peptidase assay methods, one in liquid-phase and another, in gel-phase (gel zymography), an acid peptidase was detected in protein crude extracts of epimastigotes of Trypanosoma cruzi, from a rural area of Venezuela where Chagas disease is endemic. The peptidase shows activity at a pH range between 2.0 and 2.9. Under the experimental conditions described, the acid peptidase was insensitive to usual concentrations of peptidase inhibitors of the types: serine, cysteine, aspartic and metallopeptidases. Nevertheless, like porcine pepsin at pH 2.9, the peptidase was inhibited in the presence of 5mM DTT. PMID:24354241
Organic petrology of Paleocene Marcelina Formation coals, Paso Diablo mine, western Venezuela: Tectonic controls on coal type
Hackley, P.C.; Martinez, M.
About 7??Mt of high volatile bituminous coal are produced annually from the four coal zones of the Upper Paleocene Marcelina Formation at the Paso Diablo open-pit mine of western Venezuela. As part of an ongoing coal quality study, we have characterized twenty-two coal channel samples from the mine using organic petrology techniques. Samples also were analyzed for proximate-ultimate parameters, forms of sulfur, free swelling index, ash fusion temperatures, and calorific value. Six of the samples represent incremental benches across the 12-13??m thick No. 4 bed, the stratigraphically lowest mined coal, which is also mined at the 10??km distant Mina Norte open-pit. Organic content of the No. 4 bed indicates an upward increase of woody vegetation and/or greater preservation of organic material throughout the life of the original mire(s). An upward increase in telovitrinite and corresponding decrease in detrovitrinite and inertinite illustrate this trend. In contrast, stratigraphically higher coal groups generally exhibit a 'dulling upward' trend. The generally high inertinite content, and low ash yield and sulfur content, suggest that the Paso Diablo coals were deposited in rain-fed raised mires, protected from clastic input and subjected to frequent oxidation and/or moisture stress. However, the two thinnest coal beds (both 0.7??m thick) are each characterized by lower inertinite and higher telovitrinite content relative to the rest of Paso Diablo coal beds, indicative of less well-established raised mire environments prior to drowning. Foreland basin Paleocene coals of western Venezuela, including the Paso Diablo deposit and time-correlative coal deposits of the Ta??chira and Me??rida Andes, are characterized by high inertinite and consistently lower ash and sulfur relative to Eocene and younger coals of the area. We interpret these age-delimited coal quality characteristics to be due to water availability as a function of the tectonic control of subsidence rate. It
Importance of landscape features and Earth observation derived habitat maps for modelling amphibian distribution in the Alta Murgia National Park
NASA Astrophysics Data System (ADS)
Ficetola, Gentile Francesco; Adamo, Maria; Bonardi, Anna; De Pasquale, Vito; Liuzzi, Cristiano; Lovergine, Francesco; Marcone, Francesco; Mastropasqua, Fabio; Tarantino, Cristina; Blonda, Palma; Padoa-Schioppa, Emilio
Traditionally, analyses of relationships between amphibians and habitat focused on breeding environments (i.e., pond features) more than on the features of the surrounding environment. Nevertheless, for most amphibians the terrestrial phase is longer than the aquatic phase, and consequently landscape features (i.e., habitat mosaics) may have an important role for modelling amphibian distribution. There were different aims in this analysis. Firstly, we compared the effectiveness of the information provided by land cover/use (LC/LU) classes and habitat classes defined according to a new habitat taxonomy named General Habitat Category (GHC), which is based on the concept of biological forms of dominant vegetation and class naturalness. The GHC map used was obtained from a pre-existing validated LC/LU map, by integrating spectral and spatial measurements from very high resolution Earth observation data according to ecological expert rules involving concepts related to spatial and temporal relationships among LC/LU and habitat classes. Then, we investigated the importance for amphibians of the landscape surrounding ponds within the Italian Alta Murgia National Park. The work assessed whether LC/LU classes in pond surrounds are important for the presence/absence of amphibians in this area, and identified which classes are more important for amphibians. The results obtained can provide useful indications to management strategies aiming at the conservation of amphibians within the study area. An information-theoretic approach was adopted to assess whether GHC maps allow to improve the performance of species distribution models. We used the Akaike's Information Criterion (AICc) to compare the effectiveness of GHC categories versus LC/LU categories in explaining the presence/absence of pool frogs. AICc weights suggest that GHC categories can better explain the distribution of frogs, compared to LC/LU classes.
Identification and Classification of Mass Transport Complexes in Offshore Trinidad/Venezuela and Their Potential Anthropogenic Impact as Tsunamigenic Hazards
NASA Astrophysics Data System (ADS)
Moscardelli, L.; Wood, L. J.
Several late Pleistocene-age seafloor destabilization events have been identified in the continental margin of eastern offshore Trinidad, of sufficient scale to produce tsunamigenic forces. This area, situated along the obliquely-converging-boundary of the Caribbean/South American plates and proximal to the Orinoco Delta, is characterized by catastrophic shelf-margin processes, intrusive-extrusive mobile shales, and active tectonism. A mega-merged, 10,000km2, 3D seismic survey reveals several mass transport complexes that range in area from 11.3km2 to 2017km2. Historical records indicate that this region has experienced submarine landslide- generated tsunamigenic events, including tsunamis that affected Venezuela during the 1700's-1900's. This work concentrates on defining those ancient deep marine mass transport complexes whose occurrence could potentially triggered tsunamis. Three types of failures are identified; 1) source-attached failures that are fed by shelf edge deltas whose sediment input is controlled by sea-level fluctuations and sedimentation rates, 2) source-detached systems, which occur when upper slope sediments catastrophically fail due to gas hydrate disruptions and/or earthquakes, and 3) locally sourced failures, formed when local instabilities in the sea floor trigger relatively smaller collapses. Such classification of the relationship between slope mass failures and the sourcing regions enables a better understanding of the nature of initiation, length of development history and petrography of such mass transport deposits. Source-detached systems, generated due to sudden sediment remobilizations, are more likely to disrupt the overlying water column causing a rise in tsunamigenic risk. Unlike 2D seismic, 3D seismic enables scientists to calculate more accurate deposit volumes, improve deposit imaging and thus increase the accuracy of physical and computer simulations of mass failure processes.