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Effect of temperature on laboratory growth, reproduction and life span of Octopus bimaculoides
J. W. Forsythe; R. T. Hanlon
Laboratory culture of 40 Octopus bimaculoides from April 1982 to August 1983 through the full life cycle at 18░C vs 23░C provided information on the growth, reproductive biology and life span of this California littoral octopus. At 18░C, the cephalopods grew from a hatchling size of 0.07 g to a mean of 619 g in 404 d; the largest individual
The effect of developmental nutrition on life span and fecundity depends on the adult reproductive environment in Drosophila melanogaster
May, Christina M; Doroszuk, Agnieszka; Zwaan, Bas J
Both developmental nutrition and adult nutrition affect life-history traits; however, little is known about whether the effect of developmental nutrition depends on the adult environment experienced. We used the fruit fly to determine whether life-history traits, particularly life span and fecundity, are affected by developmental nutrition, and whether this depends on the extent to which the adult environment allows females to realize their full reproductive potential. We raised flies on three different developmental food levels containing increasing amounts of yeast and sugar: poor, control, and rich. We found that development on poor or rich larval food resulted in several life-history phenotypes indicative of suboptimal conditions, including increased developmental time, and, for poor food, decreased adult weight. However, development on poor larval food actually increased adult virgin life span. In addition, we manipulated the reproductive potential of the adult environment by adding yeast or yeast and a male. This manipulation interacted with larval food to determine adult fecundity. Specifically, under two adult conditions, flies raised on poor larval food had higher reproduction at certain ages ¢ when singly mated this occurred early in life and when continuously mated with yeast this occurred during midlife. We show that poor larval food is not necessarily detrimental to key adult life-history traits, but does exert an adult environment-dependent effect, especially by affecting virgin life span and altering adult patterns of reproductive investment. Our findings are relevant because (1) they may explain differences between published studies on nutritional effects on life-history traits; (2) they indicate that optimal nutritional conditions are likely to be different for larvae and adults, potentially reflecting evolutionary history; and (3) they urge for the incorporation of developmental nutritional conditions into the central life-history concept of resource acquisition and allocation. PMID:25859322
The effect of developmental nutrition on life span and fecundity depends on the adult reproductive environment in Drosophila melanogaster.
May, Christina M; Doroszuk, Agnieszka; Zwaan, Bas J
Both developmental nutrition and adult nutrition affect life-history traits; however, little is known about whether the effect of developmental nutrition depends on the adult environment experienced. We used the fruit fly to determine whether life-history traits, particularly life span and fecundity, are affected by developmental nutrition, and whether this depends on the extent to which the adult environment allows females to realize their full reproductive potential. We raised flies on three different developmental food levels containing increasing amounts of yeast and sugar: poor, control, and rich. We found that development on poor or rich larval food resulted in several life-history phenotypes indicative of suboptimal conditions, including increased developmental time, and, for poor food, decreased adult weight. However, development on poor larval food actually increased adult virgin life span. In addition, we manipulated the reproductive potential of the adult environment by adding yeast or yeast and a male. This manipulation interacted with larval food to determine adult fecundity. Specifically, under two adult conditions, flies raised on poor larval food had higher reproduction at certain ages - when singly mated this occurred early in life and when continuously mated with yeast this occurred during midlife. We show that poor larval food is not necessarily detrimental to key adult life-history traits, but does exert an adult environment-dependent effect, especially by affecting virgin life span and altering adult patterns of reproductive investment. Our findings are relevant because (1) they may explain differences between published studies on nutritional effects on life-history traits; (2) they indicate that optimal nutritional conditions are likely to be different for larvae and adults, potentially reflecting evolutionary history; and (3) they urge for the incorporation of developmental nutritional conditions into the central life-history concept of resource acquisition and allocation. PMID:25859322
Life-Span Extension by Caloric Restriction Is Determined by Type and Level of Food Reduction and by Reproductive Mode in Brachionus manjavacas (Rotifera)
We measured life span and fecundity of three reproductive modes in a clone of the monogonont rotifer Brachionus manjavacas subjected to chronic caloric restriction (CCR) over a range of food concentrations or to intermittent fasting (IF). IF increased life span 50%¢70% for all three modes, whereas CCR increased life span of asexual females derived from sexually or asexually produced eggs, but not that of sexual females. The main effect of CR on both asexual modes was to delay death at young ages, rather than to prevent death at middle ages or to greatly extend maximum life span; in contrast CR in sexual females greatly increased the life span of a few long-lived individuals. Lifetime fecundity did not decrease with CCR, suggesting a lack of resource allocation trade-off between somatic maintenance and reproduction. Multiple outcomes for a clonal lineage indicate that different responses are established through epigenetic programming, whereas differences in life-span allocations suggest that multiple genetic mechanisms mediate life-span extension. PMID:22904096
Life-span extension by caloric restriction is determined by type and level of food reduction and by reproductive mode in Brachionus manjavacas (Rotifera).
Gribble, Kristin E; Welch, David B Mark
We measured life span and fecundity of three reproductive modes in a clone of the monogonont rotifer Brachionus manjavacas subjected to chronic caloric restriction (CCR) over a range of food concentrations or to intermittent fasting (IF). IF increased life span 50%-70% for all three modes, whereas CCR increased life span of asexual females derived from sexually or asexually produced eggs, but not that of sexual females. The main effect of CR on both asexual modes was to delay death at young ages, rather than to prevent death at middle ages or to greatly extend maximum life span; in contrast CR in sexual females greatly increased the life span of a few long-lived individuals. Lifetime fecundity did not decrease with CCR, suggesting a lack of resource allocation trade-off between somatic maintenance and reproduction. Multiple outcomes for a clonal lineage indicate that different responses are established through epigenetic programming, whereas differences in life-span allocations suggest that multiple genetic mechanisms mediate life-span extension. PMID:22904096
Reproductive life-span and sources of mortality for alternative male life-history strategies in sockeye salmon, Oncorhynchus nerka
Stephanie M. Carlson; Thomas P. Quinn
Abstract: In anadromous salmonid fishes, a fraction of the males (ōjacksö) spend fewer years at sea than females and most males in the population. It has been hypothesized,that the higher survival rates of jacks at sea are balanced,by their reduced reproductive success. One component of reproductive success is in-stream longevity, and jacks were re- ported to have a shorter reproductive
Loneliness across the life span.
Qualter, Pamela; Vanhalst, Janne; Harris, Rebecca; Van Roekel, Eeske; Lodder, Gerine; Bangee, Munirah; Maes, Marlies; Verhagen, Maaike
Most people have experienced loneliness and have been able to overcome it to reconnect with other people. In the current review, we provide a life-span perspective on one component of the evolutionary theory of loneliness-a component we refer to as the reaffiliation motive (RAM). The RAM represents the motivation to reconnect with others that is triggered by perceived social isolation. Loneliness is often a transient experience because the RAM leads to reconnection, but sometimes this motivation can fail, leading to prolonged loneliness. We review evidence of how aspects of the RAM change across development and how these aspects can fail for different reasons across the life span. We conclude with a discussion of age-appropriate interventions that may help to alleviate prolonged loneliness. PMID:25910393
Life-Span Learning: A Developmental Perspective
ERIC Educational Resources Information Center
Thornton, James E.
The article discusses learning as embedded processes of development and aging, and as social activity over the life course. The concept of life-span learning is proposed and outlined to discuss these processes as aspects of and propositions in life-span development and aging theory. Life-span learning processes arise and continuously develop in aģ
Sex difference in life span affected by female birth rate in modern humans
Alexei A. Maklakov
Sex differences in life span are common in different taxa, including primates, but not well understood. Theory and comparative evidence suggest that differential costs of reproduction between the sexes may explain the differences in sex-biased mortality across large taxonomic groups. The level of sex-specific reproductive effort may thus affect the difference in life span across populations. Modern humans (Homo sapiens),
I. Introduction Limited life span and senescence are near-
Mackay, Trudy F.C.
; Tatar et al., 2003). For example, caloric restriction extends life span in mammals (Weindruch & Walford reproduction shortens longevity in humans (Westendorp & Kirkwood, 1998), D. melanogaster (Chapman et al., 1995-like signaling pathway confer increased longevity in yeast (Fabrizio et al., 2001; Imai et al., 2000), C. elegans
Update in Female Reproduction: A Life-Cycle Approach
Robert L. Barbieri
Context: Female reproduction spans a developmental life arc from fetal life and childhood, through puberty to the reproductive years, and, finally, ovarian follicle depletion and the onset of menopause. Objective: This invited review highlights a selection of reports from leading journals over the past 2 yr that have significantly advanced our understanding of female reproduction from conception to menopause. Synthesis:
Visual Search Across the Life Span
Bernhard Hommel; Karen Z. H. Li; Shu-Chen Li
Gains and losses in visual search were studied across the life span in a representative sample of 298 individuals from 6 to 89 years of age. Participants searched for single-feature and conjunction targets of high or low eccentricity. Search was substantially slowed early and late in life, age gradients were more pronounced in conjunction than in feature search, and all
Extinction of Conservation: A Life Span Investigation
ERIC Educational Resources Information Center
Rubin, Kenneth H.
This study examined the resistance to conservation of quantity extinction in 180 subjects across the life span. The results indicated that both resistance judgments and explanations were found to develop in a curvilinear fashion, increasing with age until young adulthood and declining thereafter. (JMB)
Spatial Abilities across the Adult Life Span
ERIC Educational Resources Information Center
Borella, Erika; Meneghetti, Chiara; Ronconi, Lucia; De Beni, Rossana
The study investigates age-related effects across the adult life span on spatial abilities (testing subabilities based on a distinction between spatial visualization, mental rotation, and perspective taking) and spatial self-assessments. The sample consisted of 454 participants (223 women and 231 men) from 20 to 91 years of age. Results showedģ
Jutta Heckhausen; Richard Schulz
A life-span theory of development is presented that is based on the concepts of primary and secondary control. Primary control refers to behaviors directed at the external environment and involves attempts to change the world to fit the needs and desires of the individual. Secondary control is targeted at internal processes and serves to minimize losses in, maintain, and expand
What You Should Know about Your Reproductive Time Span
WHATYOUSHOULDKNOWABOUT Your Reproductive Time Span S ocial norms have changed over the past few decades as women are delaying marriage, choosing not to marry, ... be able to conceive right up until the time of menopause. The time of menopause for individual ...
Spatial abilities across the adult life span.
Borella, Erika; Meneghetti, Chiara; Ronconi, Lucia; De Beni, Rossana
The study investigates age-related effects across the adult life span on spatial abilities (testing subabilities based on a distinction between spatial visualization, mental rotation, and perspective taking) and spatial self-assessments. The sample consisted of 454 participants (223 women and 231 men) from 20 to 91 years of age. Results showed nonlinear age-related effects for spatial visualization and perspective taking but linear effects for mental rotation; few or no age-related effects were found for spatial self-assessments. Working memory accounted for only a small proportion of the variance in all spatial tasks and had no effect on spatial self-assessments. Overall, our findings suggest that the influence of age on spatial skills across the adult life span is considerable, but the effects of age change as a function of the spatial task considered, and the effect on spatial self-assessment is more marginal. PMID:23895173
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
78. VIEW SHOWING PLACEMENT OF LIFE SPAN SHOE ON PIER 6, LOOKING NORTH, March 5, 1935 - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA
Stress Proteins in Aging and Life Span
Murshid, Ayesha; Eguchi, Takanori; Calderwood, Stuart K.
Heat shock proteins (HSP) are molecular chaperones and have been implicated in longevity and aging in many species. Their major functions include, chaperoning misfolded or newly synthesized polypeptides, protecting cells from proteotoxic stress, and processing of immunogenic agents. These proteins are expressed constitutively and can be induced by stresses such as heat, oxidative stress and many more. The induction of HSP in aging could potentially maintain protein homeostasis and longevity by refolding the damaged proteins which accumulate during aging and are toxic to cells. HSP are shown to increase life span in model organisms such as C. elegans and decrease aging related proteotoxicity. Thus, decrease in HSP in aging is associated with disruption of cellular homeostasis which causes diseases such as cancer, cell senescence and neurodegeneration. HSP levels are decreased with aging in most organs including neurons. Aging also causes attenuation or alteration of many signaling pathways as well as the expression of transcription factors such as heat shock factor (HSF). The alteration in regulation and synthesis of Forkhead box O3a (FOXO3a) family of transcription factors as well as major antioxidant enzymes [manganese superoxide dismutase (MnSOD), catalase] are also seen in aging. Among many signaling mechanisms involved in altering longevity and aging, the insulin/IGF1 pathway and the Sir2 deacetylase are highly significant. This review inquires into the role of some of these pathways in longevity/aging along with HSP. PMID:23742046
REGULAR ARTICLE Plant phenology and life span influence soil pool
Adair, E. Carol
REGULAR ARTICLE Plant phenology and life span influence soil pool dynamics: Bromus tectorum, storage, and release. Using the replacement of C3ŁC4 perennial grasses by the invasive annual grass Bromus tectorum as a case study, we investigated the influence of phenology and life span on pulse responses
A Motivational Theory of Life-Span Development
Heckhausen, Jutta; Wrosch, Carsten; Schulz, Richard
This article had four goals. First, the authors identified a set of general challenges and questions that a life-span theory of development should address. Second, they presented a comprehensive account of their Motivational Theory of Life-Span Development. They integrated the model of optimization in primary and secondary control and the action-phase model of developmental regulation with their original life-span theory of control to present a comprehensive theory of development. Third, they reviewed the relevant empirical literature testing key propositions of the Motivational Theory of Life-Span Development. Finally, because the conceptual reach of their theory goes far beyond the current empirical base, they pointed out areas that deserve further and more focused empirical inquiry. PMID:20063963
Erythrocyte plasma membrane redox system may determine maximum life span.
Rizvi, Syed Ibrahim; Kumar, Dileep; Chakravarti, Shilpa; Singh, Prabhakar
There is great variation in the maximum life span of different species. The rate of living theory provides an explanation for the inter species difference in life span but falls short in accounting for the long life span of humans and flying birds. Although the membrane pacemaker theory given by Hulbert provides a viable explanation but there are still some unanswered questions. We propose that long living species have abnormally high activity of erythrocyte plasma membrane redox system which provides an effective armament to combat oxidative stress. The elevated PMRS hypothesis combined with Hulbert's 'membrane pacemaker' theory provides a better explanation for the observed long life span of humans and flying birds. PMID:21247707
Circadian Rhythms, Aging, and Life Span in Mammals
NSDL National Science Digital Library
Oren Froy (The Hebrew University of Jerusalem Institute of Biochemistry, Food Science and Nutrition)
Resetting the circadian clock leads to well being and increased life span, whereas clock disruption is associated with aging and morbidity. Increased longevity and improved health can be achieved by different feeding regimens that reset circadian rhythms and may lead to better synchrony in metabolism and physiology. This review focuses on recent findings concerning the relationships between circadian rhythms, aging attenuation, and life-span extension in mammals.
Leaf life span of floating-leaved plants
T. Tsuchiya
Photosynthetic capacity of floating-leaved plants is relatively high comparable with terrestrial herbaceous plants, though floating-leaved plants have a much smaller biomass with a leaf area index seldom exceeding 2m2m-2. Their rather small biomass accumulation is related to higher turnover of leaf biomass or shorter leaf life span. Life span of floating leaves reported in the literature ranged mostly from 13
Borderline Personality Disorder Across the Life Span
Melissa Hunt
Borderline personality disorder is characterized by affective dysregulation, intense, unstable interpersonal relationships, impulsivity and unstable identity. It overlaps considerably with both PTSD and bipolar spectrum disorders. Research on true late-life BPD is limited, but suggests that some of the core features of BPD including interpersonal difficulties, unstable affect and anger remain relatively unchanged, while impulsivity and identity disturbance decline or
Understanding Aggressive Behavior Across the Life Span
Liu, Jianghong; Lewis, Gary; Evans, Lois
Aggressive behavior is the observable manifestation of aggression and is often associated with developmental transitions and a range of medical and psychiatric diagnoses across the lifespan. As healthcare professionals involved in the medical and psychosocial care of patients from birth through death, nurses frequently encounterŚand may serve asŚboth victims and perpetrators of aggressive behavior in the workplace. While the nursing literature has continually reported research on prevention and treatment approaches, less emphasis has been given to understanding the etiology, including contextual precipitants of aggressive behavior. This paper provides a brief review of the biological, social, and environmental risk factors that purportedly give rise to aggressive behavior. Further, many researchers have focused specifically on aggressive behavior in adolescence and adulthood. Less attention has been given to understanding the etiology of such behavior in young children and older adults. This paper emphasizes the unique risk factors for aggressive behavior across the developmental spectrum, including childhood, adolescence, adulthood, and late life. Appreciation of the risk factors of aggressive behavior, and, in particular, how they relate to age-specific manifestations, can aid nurses in better design and implementation of prevention and treatment programs. PMID:22471771
The influence of Shc proteins on life span in mice.
Ramsey, Jon J; Tran, Dianna; Giorgio, Marco; Griffey, Stephen M; Koehne, Amanda; Laing, Steven T; Taylor, Sandra L; Kim, Kyoungmi; Cortopassi, Gino A; Lloyd, K C Kent; Hagopian, Kevork; Tomilov, Alexey A; Migliaccio, Enrica; Pelicci, Pier Giuseppe; McDonald, Roger B
The signaling molecule p66Shc is often described as a longevity protein. This conclusion is based on a single life span study that used a small number of mice. The purpose of the present studies was to measure life span in a sufficient number of mice to determine if longevity is altered in mice with decreased Shc levels (ShcKO). Studies were completed at UC Davis and the European Institute of Oncology (EIO). At UC Davis, male C57BL/6J WT and ShcKO mice were fed 5% or 40% calorie-restricted (CR) diets. In the 5% CR group, there was no difference in survival curves between genotypes. There was also no difference between genotypes in prevalence of neoplasms or other measures of end-of-life pathology. At 40% calorie restriction group, 70th percentile survival was increased in ShcKO, while there were no differences between genotypes in median or subsequent life span measures. At EIO, there was no increase in life span in ShcKO male or female mice on C57BL/6J, 129Sv, or hybrid C57BL/6J-129Sv backgrounds. These studies indicate that p66Shc is not a longevity protein. However, additional studies are needed to determine the extent to which Shc proteins may influence the onset and severity of specific age-related diseases. PMID:24336818
Chromosome dosage as a life span determinant in Caenorhabiditis elegans
Phil S. Hartman; Naoaki Ishii
Caenorhabiditis elegans males live longer than hermaphrodites when cultured individually. Since hermaphrodites contain a pair of X chromosomes (XX) and males are XO (there is no Y chromosome in C. elegans), we questioned whether chromosomal differences per se might impact life span. The use of mutations in the sex-determination genes tra-1 and her-1 allowed us to uncouple sexual phenotype from
A Life-Span Development Course for Counselors.
ERIC Educational Resources Information Center
Thomas, R. Murray
This article describes a course in life-span development designed particularly for students in counselor education programs. The description focuses on basic assumptions underlying the course plan, objectives of the course, and instructional methods and materials. Learning activities presented in detail include ones requiring students to: (1)ģ
Families and Drugs: A Life-Span Research Approach.
ERIC Educational Resources Information Center
Glynn, Thomas J.
The study of human development and behavior from a life-span perspective is an area of growing interest, and the family is a natural laboratory for this study. Research in the area of drug abuse demonstrates that drug use is not limited to any one population segment or age group, but is pervasive across population subgroups. More and more evidenceģ
Does Dietary Restriction Reduce Life Span in Male Fruit-feeding Butterflies?
Molleman, Freerk; Ding, Jimin; Boggs, Carol L.; Carey, James R.; Arlet, Ma?gorzata E.
Male life history and resource allocation is not frequently studied in aging and life span research. Here we verify that males of long-lived fruit-feeding butterfly species have reduced longevity on restricted diets (Beck 2007 Oecologia), in contrast to the common finding of longevity extension in dietary restriction experiments in Drosophila and some other organisms. Males of some of the most long-lived species of fruit-feeding butterflies were collected from Kibale Forest, Uganda, and kept on diets of either sugar or mashed banana. Seven out of eight species had non-significantly longer life spans on mashed banana diets. Data analysis using a time-varying Cox-model with species as covariate showed that males had reduced survival on the sugar diet during the first 35 days of captive life, but the effect was absent or reversed at more advanced ages. These results challenge the generality of dietary restriction as a way to extend life span in animals. We argue that such studies on males are promising tools for better understanding life history evolution and aging because males display a wider variety of tactics for obtaining reproductive success than females. PMID:19580860
Synchronizing Loss with Life Over a Life Span: A Dynamic Perspective
ERIC Educational Resources Information Center
Browning, Frank C.
Synchronizing loss with life is a dynamic journey. This article explores the myths, beliefs, and dynamics of loss and life. The purpose of the article is to help clinicians assist and support their clients with the difficulties of synchronizing loss with life as they progress on their life span journey.
Functional Fitness, Life Stress, and Transitions Across the Life Span
John Nyland; James D. Abbott
\\u000a Function refers to activities identified by a client as being essential to support physical, social, and psychological wellbeing\\u000a and to create a personal sense of a meaningful life (Physical Therapist Guide to Practice 2000; Brody 2002). Maintaining functional\\u000a fitness across the lifespan is essential both to independent living and to the overall quality of life. Functional fitness\\u000a is the presence
Essential role for autophagy in life span extension.
Madeo, Frank; Zimmermann, Andreas; Maiuri, Maria Chiara; Kroemer, Guido
Life and health span can be prolonged by calorie limitation or by pharmacologic agents that mimic the effects of caloric restriction. Both starvation and the genetic inactivation of nutrient signaling converge on the induction of autophagy, a cytoplasmic recycling process that counteracts the age-associated accumulation of damaged organelles and proteins as it improves the metabolic fitness of cells. Here we review experimental findings indicating that inhibition of the major nutrient and growth-related signaling pathways as well as the upregulation of anti-aging pathways mediate life span extension via the induction of autophagy. Furthermore, we discuss mounting evidence suggesting that autophagy is not only necessary but, at least in some cases, also sufficient for increasing longevity. PMID:25654554
HSF-1-mediated cytoskeletal integrity determines thermotolerance and life span.
Baird, Nathan A; Douglas, Peter M; Simic, Milos S; Grant, Ana R; Moresco, James J; Wolff, Suzanne C; Yates, John R; Manning, Gerard; Dillin, Andrew
The conserved heat shock transcription factor-1 (HSF-1) is essential to cellular stress resistance and life-span determination. The canonical function of HSF-1 is to regulate a network of genes encoding molecular chaperones that protect proteins from damage caused by extrinsic environmental stress or intrinsic age-related deterioration. In Caenorhabditis elegans, we engineered a modified HSF-1 strain that increased stress resistance and longevity without enhanced chaperone induction. This health assurance acted through the regulation of the calcium-binding protein PAT-10. Loss of pat-10 caused a collapse of the actin cytoskeleton, stress resistance, and life span. Furthermore, overexpression of pat-10 increased actin filament stability, thermotolerance, and longevity, indicating that in addition to chaperone regulation, HSF-1 has a prominent role in cytoskeletal integrity, ensuring cellular function during stress and aging. PMID:25324391
Caveolin-1 null (-/-) mice show dramatic reductions in life span.
Park, David S; Cohen, Alex W; Frank, Philippe G; Razani, Babak; Lee, Hyangkyu; Williams, Terence M; Chandra, Madhulika; Shirani, Jamshid; De Souza, Andrea P; Tang, Baiyu; Jelicks, Linda A; Factor, Stephen M; Weiss, Louis M; Tanowitz, Herbert B; Lisanti, Michael P
Caveolae are 50-100 nm flask-shaped invaginations of the plasma membrane found in most cell types. Caveolin-1 is the principal protein component of caveolae membranes in nonmuscle cells. The recent development of Cav-1-deficient mice has allowed investigators to study the in vivo functional role of caveolae in the context of a whole animal model, as these mice lack morphologically detectable caveolae membrane domains. Surprisingly, Cav-1 null mice are both viable and fertile. However, it remains unknown whether loss of caveolin-1 significantly affects the overall life span of these animals. To quantitatively determine whether loss of Cav-1 gene expression confers any survival disadvantages with increasing age, we generated a large cohort of mice (n = 180), consisting of Cav-1 wild-type (+/+) (n = 53), Cav-1 heterozygous (+/-) (n = 70), and Cav-1 knockout (-/-) (n = 57) animals, and monitored their long-term survival over a 2 year period. Here, we show that Cav-1 null (-/-) mice exhibit an approximately 50% reduction in life span, with major declines in viability occurring between 27 and 65 weeks of age. However, Cav-1 heterozygous (+/-) mice did not show any changes in long-term survival, indicating that loss of both Cav-1 alleles is required to mediate a reduction in life span. Mechanistically, these dramatic reductions in life span appear to be secondary to a combination of pulmonary fibrosis, pulmonary hypertension, and cardiac hypertrophy in Cav-1 null mice. Taken together, our results provide the first demonstration that loss of Cav-1 gene expression and caveolae organelles dramatically affects the long-term survival of an organism. In addition, aged Cav-1 null mice may provide a new animal model to study the pathogenesis and treatment of progressive hypertrophic cardiomyopathy and sudden cardiac death syndrome. PMID:14690422
Developmental Trajectories in Moral Reasoning Across the Life Span
Cheryl Armon; Theo L. Dawson
This long?term study found that moral reasoning as conceptualised by Kohlberg (1981, 1985) can develop into adulthood. Predominantly white, well?educated, middle?class participants were interviewed four times at 4?year intervals (N = 44). Stage development was sequential and continued throughout the life span, although its occurrence decreased with advancing age in a curvilinear fashion. Post?conventional reasoning was demonstrated by seven adults.
Studying the replicative life span of yeast cells.
Sinclair, David A
The budding yeast Saccharomyces cerevisiae is a useful model for elucidating the pathways that control life span and the influence of environmental factors, such as calorie restriction (CR). For 75 years, CR has been studied for its ability to delay diseases of aging in mammals, from cancer to cardiovascular disease (McCay et al., Nutr Rev 33:241-243, 1975). In many other species, reducing calorie intake extends life span, including unicellular organisms (Jiang et al., FASEB J 14:2135-2137, 2000; Lin et al., Science 289:2126-2128, 2000), invertebrates (Rogina and Helfand, Proc Natl Acad Sci U S A 101:15998-16003, 2004), and rodents (MartĒn-Montalvo et al., Oncogene 30:505-520, 2011). Here we describe how to calorically restrict yeast cells, the methods used to determine the replicative life span (RLS) of budding yeast cells, how to selectively kill daughter cells using the mother enrichment program (MEP), how to measure recombination frequency at the rDNA locus, how to isolate large quantities of old cells, and how to analyze the circular forms of DNA known as extrachromosomal rDNA circles (ERCs), a cause of aging in S. cerevisiae (Petes, Cell 19:765-774, 1980; Sinclair and Guarente, Cell 91:1033-1042, 1997; Defossez et al., Mol Cell 3:447-455, 1999). PMID:23929097
Amino acid sources in the adult diet do not affect life span and fecundity in the fruit-feeding butterfly Bicyclus anynana
Molleman, Freerk; Ding, Jimin; Wang, Jane-Ling; Brakefield, Paul M.; Carey, James R.; Zwaan, Bas J.
1. In tropical forests, the adults of many butterfly species feed on fruits rather than nectar from flowers and have long life spans. Rotting fruit and nectar differ from each other in many respects, including sources of amino acids and microbial life. If amino acids in the adult diet can be used for reproduction, this may have facilitated the evolution of extended life spans in this guild. 2. This issue was addressed by investigating effects of banana, yeast, and amino acids in the adult diet of the fruit-feeding butterfly Bicyclus anynana (Lepidoptera) on longevity and female reproductive output in two experiments. 3. Results showed that in the fruit-feeding butterfly B. anynana: (i) banana juice, but not sliced banana or added amino acids extend life span compared with a sugar solution of similar composition; (ii) compared with this sugar solution, other cohorts (banana juice-amino acid enriched) did not have significantly higher reproductive outputs; (iii) yeast does not represent a valuable source of nutrients; (iv) caloric restriction may cause decreased life span and rate of reproduction; and (v) increased rates of reproduction have a life span cost. PMID:19081752
The Life Cycle and Life Span of Namibian Fairy Circles
Tschinkel, Walter R.
In Namibia of southwestern Africa, the sparse grasslands that develop on deep sandy soils under rainfall between 50 and 100 mm per annum are punctuated by thousands of quasi-circular bare spots, usually surrounded by a ring of taller grass. The causes of these so-called ōfairy circlesö are unknown, although a number of hypotheses have been proposed. This paper provides a more complete description of the variation in size, density and attributes of fairy circles in a range of soil types and situations. Circles are not permanent; their vegetative and physical attributes allow them to be arranged into a life history sequence in which circles appear (birth), develop (mature) and become revegetated (die). Occasionally, they also enlarge. The appearance and disappearance of circles was confirmed from satellite images taken 4 years apart (2004, 2008). The frequency of births and deaths as a fraction of the total population of circles allowed the calculation of an approximate turnover rate, and from this, an estimate of circle lifespan. Lifespan appeared to vary with circle size, with small circles averaging about 24 years, and larger ones 43¢75 years. Overall lifespan averaged about 41 yr. A second, independent estimate of lifespan was made by revisiting circles 2 to 9 years after their clear status had been confirmed. This resulted in a lifespan estimate of about 60 years. Any causal explanation of fairy circles must include their birth, development and death, their mean lifespan and the variation of their features under different conditions. PMID:22761663
IQ and ability across the adult life span.
Baxendale, Sallie
The experience of cognitive decline can be a potent source of anxiety and concern for many people. While an IQ consistent with estimated optimal levels or previously recorded scores may indicate no significant change in cognitive function, the patient may be accurately reporting a normal age-related deterioration in actual ability. The aim of this article is to chart the age-related changes in intellectual abilities evident on the Wechsler Adult Intelligence Scales-Fourth Edition (WAIS-IV). The norms from the WAIS-IV manual were examined to plot the age-related changes in Full-Scale IQ (FSIQ) and composite scores across the adult life span, while holding actual ability level constant across the age groups. Here we present a graphical representation of the normal cognitive developments and declines in FSIQ, Verbal Comprehension, Perceptual Reasoning, Working Memory, and Processing Speed across the adult life span. This graphical representation provides a rational basis for the identification of atypical profiles/complaints of cognitive deterioration that may require further specialist neuropsychological evaluation. These graphs can be used to provide reassurance for healthy adults with concerns of cognitive decline and as an educative tool for their referring agencies. PMID:21846215
Life-span studies of inhaled plutonium in beagle dogs
Bair, W.J.
In 1970 a life-span study with over 300 beagle dogs was begun to gain an understanding of long-term health effects resulting from respiratory tract intakes of plutonium and to derive risk estimates that might be applied to plutonium and other transuranic elements. Groups of beagle dogs were given single exposures to {sup 239}PuO{sub 2}, {sup 238}PuO{sub 2}, or {sup 239}Pu(NO{sub 3}){sub 4} to obtain graded levels of initial lung burdens ranging from 1 to 1800 Bq lung. The objective of this paper is to give you a progress report on the current life-span studies of inhaled plutonium in beagle dogs at the Pacific Northwest Laboratory. I will describe the biokinetics of inhaled plutonium in dogs and the resulting health effects. I will also mention some studies directed towards understanding the mechanism leading to these effects. Finally, I will discuss the current risk estimates derived from these studies and how they might relate to plutonium exposures in humans. 5 refs., 13 figs., 4 tabs.
SNEV overexpression extends the life span of human endothelial cells
Voglauer, Regina [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria); Chang, Martina Wei-Fen [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria); Dampier, Brigitta [Department of Obstetrics and Gynecology, Medical University of Vienna, A-1090 Vienna (Austria); Wieser, Matthias [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria); Baumann, Kristin [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria); Sterovsky, Thomas [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria); Schreiber, Martin [Department of Obstetrics and Gynecology, Medical University of Vienna, A-1090 Vienna (Austria); Katinger, Hermann [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria); Grillari, Johannes [Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences Muthgasse 18, A-1190 Vienna (Austria) and BMT Research Vienna (Austria)]. E-mail: firstname.lastname@example.com
In a recent screening for genes downregulated in replicatively senescent human umbilical vein endothelial cells (HUVECs), we have isolated the novel protein SNEV. Since then SNEV has proven as a multifaceted protein playing a role in pre-mRNA splicing, DNA repair, and the ubiquitin/proteosome system. Here, we report that SNEV mRNA decreases in various cell types during replicative senescence, and that it is increased in various immortalized cell lines, as well as in breast tumors, where SNEV transcript levels also correlate with the survival of breast cancer patients. Since these mRNA profiles suggested a role of SNEV in the regulation of cell proliferation, the effect of its overexpression was tested. Thereby, a significant extension of the cellular life span was observed, which was not caused by altered telomerase activity or telomere dynamics but rather by enhanced stress resistance. When SNEV overexpressing cells were treated with bleomycin or bleomycin combined with BSO, inducing DNA damage as well as reactive oxygen species, a significantly lower fraction of apoptotic cells was found in comparison to vector control cells. These data suggest that high levels of SNEV might extend the cellular life span by increasing the resistance to stress or by improving the DNA repair capacity of the cells.
The progesterone antagonist mifepristone/RU486 blocks the negative effect on life span caused by mating in female Drosophila
Landis, Gary N.; Salomon, Matthew P.; Keroles, Daniel; Brookes, Nicholas; Sekimura, Troy; Tower, John
Mating causes decreased life span in female Drosophila. Here we report that mifepristone blocked this effect, yielding life span increases up to +68%. Drug was fed to females after mating, in the absence of males, demonstrating function in females. Mifepristone did not increase life span of virgin females or males. Mifepristone reduced progeny production but did not reduce food intake. High-throughput RNA sequencing was used to identify genes up-regulated or down-regulated upon mating, and where the change was reduced by mifepristone. Five candidate positive regulators of life span were identified, including dosage compensation regulator Unr and three X-linked genes: multi sex combs (PcG gene), Dopamine 2-like receptor and CG14215. The 37 candidate negative genes included neuropeptide CNMamide and several involved in protein mobilization and immune response. The results inform the interpretation of experiments involving mifepristone, and implicate steroid hormone signaling in regulating the trade-off between reproduction and life span. PMID:25614682
Quantitative and Molecular Genetic Analyses of Mutations Increasing Drosophila Life Span
Magwire, Michael M.; Yamamoto, Akihiko; Carbone, Mary Anna; Roshina, Natalia V.; Symonenko, Alexander V.; Pasyukova, Elena G.; Morozova, Tatiana V.; Mackay, Trudy F. C.
Understanding the genetic and environmental factors that affect variation in life span and senescence is of major interest for human health and evolutionary biology. Multiple mechanisms affect longevity, many of which are conserved across species, but the genetic networks underlying each mechanism and cross-talk between networks are unknown. We report the results of a screen for mutations affecting Drosophila life span. One third of the 1,332 homozygous P¢element insertion lines assessed had quantitative effects on life span; mutations reducing life span were twice as common as mutations increasing life span. We confirmed 58 mutations with increased longevity, only one of which is in a gene previously associated with life span. The effects of the mutations increasing life span were highly sex-specific, with a trend towards opposite effects in males and females. Mutations in the same gene were associated with both increased and decreased life span, depending on the location and orientation of the P¢element insertion, and genetic background. We observed substantialŚand sex-specificŚepistasis among a sample of ten mutations with increased life span. All mutations increasing life span had at least one deleterious pleiotropic effect on stress resistance or general health, with different patterns of pleiotropy for males and females. Whole-genome transcript profiles of seven of the mutant lines and the wild type revealed 4,488 differentially expressed transcripts, 553 of which were common to four or more of the mutant lines, which include genes previously associated with life span and novel genes implicated by this study. Therefore longevity has a large mutational target size; genes affecting life span have variable allelic effects; alleles affecting life span exhibit antagonistic pleiotropy and form epistatic networks; and sex-specific mutational effects are ubiquitous. Comparison of transcript profiles of long-lived mutations and the control line reveals a transcriptional signature of increased life span. PMID:20686706
Variation of color discrimination across the life span.
Paramei, Galina V; Oakley, Beata
The present study, an extension of Paramei [J. Opt. Soc. Am. A, 29, A290, 2012], provides normative data on chromatic discrimination, using the Cambridge Colour Test, for normal trichromats aged 10-88 years. Findings are in accord with a two-phase variation across the life span: chromatic sensitivity improves in adolescence, reaches a maximum around 30 years, and then undergoes a gradual decrease. Indicative parameters are Protan (P), Deutan (D), and Tritan (T) vector lengths and major axes and axis ratios of Ellipses. Trivector data are modeled as non-monotonic combinations of power functions, with goodness-of-fits R(P)2=0.23, R(D)2=0.23, and R(T)2=0.45. For advancing age, sensitivity decline in all chromatic systems was confirmed, though with a marked acceleration after 60 years (reflected by the power function exponent >1) and more pronounced for the tritan system. PMID:24695196
Explanations of a magic trick across the life span
Olson, Jay A.; Demacheva, Irina; Raz, Amir
Studying how children and adults explain magic tricks can reveal developmental differences in cognition. We showed 167 children (aged 4¢13 years) a video of a magician making a pen vanish and asked them to explain the trick. Although most tried to explain the secret, none of them correctly identified it. The younger children provided more supernatural interpretations and more often took the magician's actions at face value. Combined with a similar study of adults (N = 1008), we found that both young children and older adults were particularly overconfident in their explanations of the trick. Our methodology demonstrates the feasibility of using magic to study cognitive development across the life span. PMID:25798117
Theoretical Propositions of Life-Span Developmental Psychology: On the Dynamics Between Growth and Decline
Paul B. Baltes
Life-span developmental psychology involves the study of constancy and change in behavior throughout the life course. One aspect of life-span research has been the advancement of a more general, metatheoretical view on the nature of development. The family of theoretical perspectives associated with this metatheoretical view of life-span developmental psychology includes the recog- nition of multidirectionality in ontogenetic change, consideration
Theoretical Propositions of Life-Span Developmental Psychology: On the Dynamics Between Growth and Decline
Paul B. Baltes
Life-span developmental psychology involves the study of constancy and change in behavior throughout the life course. One aspect of life-span research has been the advancement of a more general, metatheoretical view on the nature of development. The family of theoretical perspectives associated with this metatheoretical view of life-span developmental psychology includes the recognition of multidirectionality in ontogenetic change, consideration of
Mice generated by in vitro fertilization exhibit vascular dysfunction and shortened life span.
Rexhaj, Emrush; Paoloni-Giacobino, Ariane; Rimoldi, Stefano F; Fuster, Daniel G; Anderegg, Manuel; Somm, Emmanuel; Bouillet, Elisa; Allemann, Yves; Sartori, Claudio; Scherrer, Urs
Children conceived by assisted reproductive technologies (ART) display a level of vascular dysfunction similar to that seen in children of mothers with preeclamspia. The long-term consequences of ART-associated vascular disorders are unknown and difficult to investigate in healthy children. Here, we found that vasculature from mice generated by ART display endothelial dysfunction and increased stiffness, which translated into arterial hypertension in vivo. Progeny of male ART mice also exhibited vascular dysfunction, suggesting underlying epigenetic modifications. ART mice had altered methylation at the promoter of the gene encoding eNOS in the aorta, which correlated with decreased vascular eNOS expression and NO synthesis. Administration of a deacetylase inhibitor to ART mice normalized vascular gene methylation and function and resulted in progeny without vascular dysfunction. The induction of ART-associated vascular and epigenetic alterations appeared to be related to the embryo environment; these alterations were possibly facilitated by the hormonally stimulated ovulation accompanying ART. Finally, ART mice challenged with a high-fat diet had roughly a 25% shorter life span compared with control animals. This study highlights the potential of ART to induce vascular dysfunction and shorten life span and suggests that epigenetic alterations contribute to these problems. PMID:24270419
Impaired respiration is positively correlated with decreased life span in Caenorhabditis elegans models of Friedreich Ataxia
Kim Zarse; Tim J. Schulz; Marc Birringer; Michael Ristow
Impaired expression of mitochondrial genes causes alterations in life span of the nematode Caenorhabditis elegans. Intriguingly, although some of these genes have been shown to extend life expectancy and reduce aging processes, others are known to shorten life span in the same model organism. Reduced expression of a mitochondrial protein called frataxin causes a neurodegenerative disorder named Friedreich Ataxia, which
Reproductive and Life History Parameters of Wild Female Macaca assamensis
Ines F³rtbauer; Oliver Sch³lke; Michael Heistermann; Julia Ostner
Information on basic reproductive parameters and life-history traits is crucial for the understanding of primate evolution,\\u000a ecology, social behavior, and reproductive strategies. Here, we report 4Āyr of data on reproductive and life-history traits\\u000a for wild female Assamese macaques (Macaca assamensis) at Phu Khieo Wildlife Sanctuary, northeastern Thailand. During 2 consecutive reproductive seasons, we investigated reproductive\\u000a behavior and sexual swelling size
The evolution of prolonged life after reproduction.
Croft, Darren P; Brent, Lauren J N; Franks, Daniel W; Cant, Michael A
Why females of some species cease ovulation before the end of their natural lifespan is a longstanding evolutionary puzzle. For many species in captivity, post-reproductive life is simply an epiphenomenon of lengthened lifespan. Yet in natural populations of humans as well as some cetaceans and insects, reproductive senescence occurs much faster than somatic aging and females exhibit prolonged post-reproductive lifespans (PRLSs). Determining the mechanisms and functions that underpin PRLSs has proved a significant challenge. Here we bring together both classic and modern hypotheses proposed to explain PRLSs and discuss their application to both human and nonhuman animals. By taking an integrative and broad taxonomic approach we highlight the need to consider multiple interacting explanations for the evolution of PRLSs. PMID:25982154
Ovariectomy shortens the life span of female mice.
Benedusi, Valeria; Martini, Elisa; Kallikourdis, Marinos; Villa, Alessandro; Meda, Clara; Maggi, Adriana
This study shows that lack of ovarian activity has a negative impact on the life span of female mice. The extent to which this phenomenon could be associated with the anti-inflammatory effect of estrogens was analyzed in metabolic organs and aorta, by quantitative analysis of mRNAs encoding proteins in the inflammatory cascade. We demonstrate that the TNF?, IL-1?, MCP-1, MIP-2 and IL-6 mRNA contents are increased in the liver, adipose tissue and aorta 7 months after ovariectomy (ovx) and this increased basal inflammation is maintained as the mice aged. In contrast, the extent of inflammatory gene expression is directly proportional to age in sham-operated mice. As a consequence, at 22 months, most of the inflammatory parameters examined were higher in the sham-operated group compared with the ovx group. These observations led us to propose that the decreased longevity of ovx mice may be due to an acceleration of the basal state of inflammation in metabolic organs, which is likely driven by the combination of a lack of estrogen-mediated anti-inflammatory activity and the loss of gonadal control of energy metabolism. PMID:25719423
Ovariectomy shortens the life span of female mice
Benedusi, Valeria; Martini, Elisa; Kallikourdis, Marinos; Villa, Alessandro; Meda, Clara; Maggi, Adriana
This study shows that lack of ovarian activity has a negative impact on the life span of female mice. The extent to which this phenomenon could be associated with the anti-inflammatory effect of estrogens was analyzed in metabolic organs and aorta, by quantitative analysis of mRNAs encoding proteins in the inflammatory cascade. We demonstrate that the TNF?, IL-1?, MCP-1, MIP-2 and IL-6 mRNA contents are increased in the liver, adipose tissue and aorta 7 months after ovariectomy (ovx) and this increased basal inflammation is maintained as the mice aged. In contrast, the extent of inflammatory gene expression is directly proportional to age in sham-operated mice. As a consequence, at 22 months, most of the inflammatory parameters examined were higher in the sham-operated group compared with the ovx group. These observations led us to propose that the decreased longevity of ovx mice may be due to an acceleration of the basal state of inflammation in metabolic organs, which is likely driven by the combination of a lack of estrogen-mediated anti-inflammatory activity and the loss of gonadal control of energy metabolism. PMID:25719423
Programmed life span in the context of evolvability.
Mitteldorf, Joshua; Martins, Andrķ C R
Population turnover is necessary for progressive evolution. In the context of a niche with fixed carrying capacity, aging contributes to the rate of population turnover. Theoretically, a population in which death is programmed on a fixed schedule can evolve more rapidly than one in which population turnover is left to a random death rate. Could aging evolve on this basis? Quantitative realization of this idea is problematic, since the short-term individual fitness cost is likely to eliminate any hypothetical gene for programmed death before the long-term benefit can be realized. In 2011, one of us proposed the first quantitative model based on this mechanism that robustly evolves a finite, programmed life span. That model was based on a viscous population in a rapidly changing environment. Here, we strip this model to its essence and eliminate the assumption of environmental change. We conclude that there is no obvious way in which this model is unrealistic, and that it may indeed capture an important principle of nature's workings. We suggest aging may be understood within the context of the emerging science of evolvability. PMID:25141139
Life span changes in the verbal categorization of odors.
Russell, M J; Cummings, B J; Profitt, B F; Wysocki, C J; Gilbert, A N; Cotman, C W
An odor description task was used to explore age-related change in odor perception based on 1.19 million U.S. and Canadian respondents (ages 10-90 years) to the National Geographic Smell Survey. Respondents sampled six microencapsulated odorants and selected 1 of 11 descriptors to characterize each smell. Four odors were characterized by strong consensus endorsement of a single descriptor. This consensus weakened with advancing age, and nonmodal descriptors were endorsed more frequently. Nonmodal responses were neither randomly selected, nor systematically biased across odors. Rather, they showed odor-specific patterns of change. Together, these results suggest a marked change in odor categorization across the life span. Odor descriptor profiles were used to generate age-specific multidimensional scaling maps. Stimulus configurations were stable from the third through fifth decades. Those from the sixth through ninth decades showed major displacements for two odors, and suggest that the sweet dimension of odor quality may be particularly variable with maturation. PMID:8473697
Genotype-Environment Interaction for Quantitative Trait Loci Affecting Life Span in Drosophila melanogaster
Cristina Vieira; Elena G. Pasyukova; Zhao-Bang Zeng; J. Brant Hackett; Richard F. Lyman; Trudy F. C. Mackay
The nature of genetic variation for Drosophila longevity in a population of recombinant inbred lines was investigated by estimating quantitative genetic parameters and mapping quantitative trait loci (QTL) for adult life span in five environments: standard culture conditions, high and low temperature, and heat- shock and starvation stress. There was highly significant genetic variation for life span within each sex
Effect of caloric restriction on life span of the housefly, Musca domestica
T. Michael Cooper; Robin J. Mockett; Barbara H. Sohal; Rajindar S. Sohal; William C. Orr
Caloric restriction (CR) has been found to extend the life spans of a wide variety of species, transcending phylogenetic boundaries. The objective of this study was to test the generality of this phenomenon, using the male housefly as an insect model in which food intake can be quantified precisely. Sucrose was found to promote a longer life span than diets
An intervention resembling caloric restriction prolongs life span and retards aging in yeast
James C. Jiang; Ewa Jaruga; Marina V. Repnevskaya; S. Michal Jazwinski
The yeast Saccharomyces cerevisiae has a finite life span that is measured by the number of daughter cells an individual produces. The 20 genes known to determine yeast life span appear to function in more than one pathway, implicating a variety of physiological processes in yeast longevity. Less attention has been focused on environmental effects on yeast aging. We have
Global quantification of contrasting leaf life span strategies for deciduous and
Minnesota, University of
RESEARCH PAPER Global quantification of contrasting leaf life span strategies for deciduous Department of Forest Resources, University of Minnesota, St Paul, MN 55108, USA ABSTRACT Aim Species with deciduous and evergreen leaf habits typically differ in leaf life span (LLS). Yet quantification
Skill Learning as a Concept in Life-Span Developmental Psychology: An Action Theoretic Analysis
Michael Frese; Judith Stewart
An action theoretic account of skill learning and skill use is offered as a useful heuristic for life-span developmental psychology. It is suggested that analyses of the tasks confronting an individual and of the structure of action, as well as of the interplay of these two, have implications for the understanding of development across the life span. In particular, these
The Rate of Source Memory Decline across the Adult Life Span
ERIC Educational Resources Information Center
Cansino, Selene; Estrada-Manilla, Cinthya; Hernandez-Ramos, Evelia; Martinez-Galindo, Joyce Graciela; Torres-Trejo, Frine; Gomez-Fernandez, Tania; Ayala-Hernandez, Mariana; Osorio, David; Cedillo-Tinoco, Melisa; Garces-Flores, Lissete; Gomez-Melgarejo, Sandra; Beltran-Palacios, Karla; Guadalupe Garcia-Lazaro, Haydee; Garcia-Gutierrez, Fabiola; Cadena-Arenas, Yadira; Fernandez-Apan, Luisa; Bartschi, Andrea; Resendiz-Vera, Julieta; Rodriguez-Ortiz, Maria Dolores
Previous studies have suggested that the ability to remember contextual information related to specific episodic experiences declines with advancing age; however, the exact moment in the adult life span when this deficit begins is still controversial. Source memory for spatial information was tested in a life span sample of 1,500 adults betweenģ
The Time of Our Lives: Life Span Development of Timing and Event Tracking
ERIC Educational Resources Information Center
McAuley, J. Devin; Jones, Mari Riess; Holub, Shayla; Johnston, Heather M.; Miller, Nathaniel S.
Life span developmental profiles were constructed for 305 participants (ages 4-95) for a battery of paced and unpaced perceptual-motor timing tasks that included synchronize-continue tapping at a wide range of target event rates. Two life span hypotheses, derived from an entrainment theory of timing and event tracking, were tested. A preferredģ
Genetic analysis of hemopoietic cell cycling in mice suggests its involvement in organismal life span
Normal somatic cells undergo replica- tive senescence in vitro but the significance of this process in organismic aging remains controversial. We have shown previously that hemopoietic stem cells of common inbred strains of mice vary widely in cycling activity and that this parameter is inversely correlated with strain-dependent mean life span. To assess whether cell cycling and life span are
The Influence of Dietary Fat Source on Life Span in Calorie Restricted Mice.
L¾pez-DomĒnguez, Josķ A; Ramsey, Jon J; Tran, Dianna; Imai, Denise M; Koehne, Amanda; Laing, Steven T; Griffey, Stephen M; Kim, Kyoungmi; Taylor, Sandra L; Hagopian, Kevork; Villalba, Josķ M; L¾pez-Lluch, Guillermo; Navas, Plßcido; McDonald, Roger B
Calorie restriction (CR) without malnutrition extends life span in several animal models. It has been proposed that a decrease in the amount of polyunsaturated fatty acids (PUFAs), and especially n-3 fatty acids, in membrane phospholipids may contribute to life span extension with CR. Phospholipid PUFAs are sensitive to dietary fatty acid composition, and thus, the purpose of this study was to determine the influence of dietary lipids on life span in CR mice. C57BL/6J mice were assigned to four groups (a 5% CR control group and three 40% CR groups) and fed diets with soybean oil (high in n-6 PUFAs), fish oil (high in n-3 PUFAs), or lard (high in saturated and monounsaturated fatty acids) as the primary lipid source. Life span was increased (p < .05) in all CR groups compared to the Control mice. Life span was also increased (p < .05) in the CR lard mice compared to animals consuming either the CR fish or soybean oil diets. These results indicate that dietary lipid composition can influence life span in mice on CR, and suggest that a diet containing a low proportion of PUFAs and high proportion of monounsaturated and saturated fats may maximize life span in animals maintained on CR. PMID:25313149
Chronic Ills May Add Up to A Shortened Life Span
... stroke can cut up to 15 years of life expectancy To use the sharing features on this page, ... being even greater than the years lost in life expectancy among lifelong smokers and HIV patients. Smokers and ...
[Surfactant replacement therapy increases life-span of patients with acute respiratory distress syndrome].
Potapov, A L; Novikov, N Iu; Tumanski?, V A; Babanin, A A
The aim of the study is the evaluation of the influence of surfactant replacement therapy on the life-span of patients with acute respiratory distress syndrome (ARDS) in fatal cases. It has been determined, that in patients, were died from ARDS, exogenous surfactant therapy increases life-span from the moment of establishing of diagnosis of syndrome to fatal outcome. The initial functional state of lungs does not influence on life-span of patients with ARDS, but administration of exogenous surfactant is the important predictor of its increase. PMID:23705485
Senescence in Organisms with Clonal Reproduction and Complex Life Histories
Orive, Maria E.
A population genetics model is developed predicting the fate of alleles affecting life-history attributes in organisms with complex life histories, including clonal reproduction and indeterminate growth. Such organisms are ...
The Time of Our Lives: Life Span Development of Timing and Event Tracking
Liu, Taosheng
span developmental profiles were constructed for 305 participants (ages 4Ł95) for a battery of paced) of event tracking across the life span. An entrainment region hypothesis predicted a quadratic profile psychological question concerns how people ef- fectively coordinate their behavior with the dynamic unfolding
Identity Processes and Perceptions of the Life Span in Chronic Mental Patients.
ERIC Educational Resources Information Center
Whitbourne, Susan Krauss; Sherry, Michael
Investigated identity and life-span perceptions of 37 chronic mental patients, aged 23 to 64 years of age. Findings from life drawing projective technique revealed age differences in adaptation of identity to life experiences associated with mental illness. Younger subjects were more likely to adopt patient identity; older subjects adapted toģ
Imaging Hippocampal Function across the Human Life Span: Is Memory Decline
. If so, as larger segments of the population are entering late life, memory decline among the elderlyImaging Hippocampal Function across the Human Life Span: Is Memory Decline Normal or Not? Scott A,3 Memory function commonly declines in later life. Whether memory decline represents a disease process
Self-Determination across the Life Span: Issues and Gaps
ERIC Educational Resources Information Center
Heller, Tamar; Schindler, Abigail; Palmer, Susan B.; Wehmeyer, Michael L.; Parent, Wendy; Jenson, Ronda; Abery, Brian H.; Geringer, Wendy; Bacon, Ansley; O'Hara, David M.
This article synthesizes the literature on self-determination across the lifespan with a focus on identifying gaps that exist between theory, research, and evidence-based practices. Using a life-stages approach, it first examines issues across life phases, and then examines cross-cutting topics (employment, abuse and neglect, and health) that areģ
The Time of Our Lives: Life Span Development of Timing and Event Tracking
J. Devin McAuley; Mari Riess Jones; Shayla Holub; Heather M. Johnston; Nathaniel S. Miller
Life span developmental profiles were constructed for 305 participants (ages 4¢95) for a battery of paced and unpaced perceptual-motor timing tasks that included synchronize-continue tapping at a wide range of target event rates. Two life span hypotheses, derived from an entrainment theory of timing and event tracking, were tested. A preferred period hypothesis predicted a monotonic slowing of a preferred
Extension of Life-Span with Superoxide Dismutase\\/Catalase Mimetics
Simon Melov; Joanne Ravenscroft; Sarwatt Malik; Matt S. Gill; David W. Walker; Peter E. Clayton; Douglas C. Wallace; Bernard Malfroy; Susan R. Doctrow; Gordon J. Lithgow
We tested the theory that reactive oxygen species cause aging. We augmented the natural antioxidant systems of Caenorhabditis elegans with small synthetic superoxide dismutase\\/catalase mimetics. Treatment of wild-type worms increased their mean life-span by a mean of 44 percent, and treatment of prematurely aging worms resulted in normalization of their life-span (a 67 percent increase). It appears that oxidative stress
Disentangling environmental effects on adult life span in a butterfly across the metamorphic boundary.
Bauerfeind, Stephanie S; Perlick, Jana E C; Fischer, Klaus
Life span is a central life history trait often showing tremendous variation within populations. Much of this variation can be attributed to environmental factors. In holometabolous insects life stages differ strikingly in physiology and energetic demands, and environmental variation before and after metamorphosis may not necessarily yield identical responses. In this study, we adopted a full-factorial experimental design with two larval and two adult temperatures as well as two larval and three adult feeding treatments (n(total)=1151). Identical temperatures yielded qualitatively different results depending on the developmental stage. While the lower compared to the higher developmental temperature slightly reduced adult life span, a lower adult temperature substantially increased life span. Food stress in the larval stage slightly reduced life span, as did food stress during the adult stage. Females lived generally longer than males. All factors investigated were involved in interactions with other factors, both within and across life stages. For instance, the qualitative impact of larval food stress depended on adult feeding treatment and adult temperature. Our results suggest that much insight into the causes of variation in life span is to be gained by explicitly considering environmental impacts across developmental stages and potential interactions among different environmental factors. PMID:19836442
Herbal Supplement Extends Life Span Under Some Environmental Conditions and Boosts Stress Resistance
Villeponteau, Bryant; Matsagas, Kennedy; Nobles, Amber C.; Rizza, Cristina; Horwitz, Marc; Benford, Gregory; Mockett, Robin J.
Genetic studies indicate that aging is modulated by a great number of genetic pathways. We have used Drosophila longevity and stress assays to test a multipath intervention strategy. To carry out this strategy, we supplemented the flies with herbal extracts (SC100) that are predicted to modulate the expression of many genes involved in aging and stress resistance, such as mTOR, NOS, NF-KappaB, and VEGF. When flies were housed in large cages with SC100 added, daily mortality rates of both male and female flies were greatly diminished in mid to late life. Surprisingly, SC100 also stabilized midlife mortality rate increases so as to extend the maximum life span substantially beyond the limits previously reported for D. melanogaster. Under these conditions, SC100 also promoted robust resistance to partial starvation stress and to heat stress. Fertility was the same initially in both treated and control flies, but it became significantly higher in treated flies at older ages as the fertility of control flies declined. Mean and maximum life spans of flies in vials at the same test site were also extended by SC100, but the life spans were short in absolute terms. In contrast, at an independent test site where stress was minimized, the flies exhibited much longer mean life spans, but the survival curves became highly rectangular and the effects of SC100 on both mean and maximum life spans declined greatly or were abolished. The data indicate that SC100 is a novel herbal mix with striking effects on enhancing Drosophila stress resistance and life span in some environments, while minimizing mid to late life mortality rates. They also show that the environment and other factors can have transformative effects on both the length and distribution of survivorship, and on the ability of SC100 to extend the life span. PMID:25879540
History, Narrative, and Life-Span Developmental Knowledge.
ERIC Educational Resources Information Center
Freeman, Mark
Argues that the study of the life course is necessarily a historical form of inquiry that demands acknowledgment of narrative structure. Because the data of narration derive from experience, the idea of development can only be placed within the realm of subjectivity. (RH)
Female Career Commitment (A Life-Span Perspective). Special Report.
ERIC Educational Resources Information Center
van Rooyen, J.
A study that examined the personality and environmental factors affecting South African female career interest and career commitment at different life phases resulted in development of a model of vocational behavior. Selected for the study sample were 111 graduated white women employed by the Council for Scientific and Industrial Research. Theģ
Metformin slows down aging and extends life span of female SHR mice.
Anisimov, Vladimir N; Berstein, Lev M; Egormin, Peter A; Piskunova, Tatiana S; Popovich, Irina G; Zabezhinski, Mark A; Tyndyk, Margarita L; Yurova, Maria V; Kovalenko, Irina G; Poroshina, Tatiana E; Semenchenko, Anna V
Studies in mammals have led to the suggestion that hyperglycemia and hyperinsulinemia are important factors both in aging and in the development of cancer. It is possible that the life-prolonging effects of calorie restriction are due to decreasing IGF-1 levels. A search of pharmacological modulators of insulin/IGF-1 signaling pathway (which resemble effects of life span extending mutations or calorie restriction) could be a perspective direction in regulation of longevity. Antidiabetic biguanides are most promising among them. Here we show the chronic treatment of female outbred SHR mice with metformin (100 mg/kg in drinking water) slightly modified the food consumption but decreased the body weight after the age of 20 months, slowed down the age-related switch-off of estrous function, increased mean life span by 37.8%, mean life span of last 10% survivors by 20.8%, and maximum life span by 2.8 months (+10.3%) in comparison with control mice. On the other side, treatment with metformin failed influence blood estradiol concentration and spontaneous tumor incidence in female SHR mice. Thus, antidiabetic biguanide metformin dramatically extends life span, even without cancer prevention in this model. PMID:18728386
Decreased Energy Metabolism Extends Life Span in Caenorhabditis elegans Without Reducing Oxidative Damage
Van Raamsdonk, Jeremy Michael; Meng, Yan; Camp, Darius; Yang, Wen; Jia, Xihua; Bķnard, Claire; Hekimi, Siegfried
On the basis of the free radical and rate of living theories of aging, it has been proposed that decreased metabolism leads to increased longevity through a decreased production of reactive oxygen species (ROS). In this article, we examine the relationship between mitochondrial energy metabolism and life span by using the Clk mutants in Caenorhabditis elegans. Clk mutants are characterized by slow physiologic rates, delayed development, and increased life span. This phenotype suggests that increased life span may be achieved by decreasing energy expenditure. To test this hypothesis, we identified six novel Clk mutants in a screen for worms that have slow defecation and slow development and that can be maternally rescued. Interestingly, all 11 Clk mutants have increased life span despite the fact that slow physiologic rates were used as the only screening criterion. Although mitochondrial function is decreased in the Clk mutants, ATP levels are normal or increased, suggesting decreased energy utilization. To determine whether the longevity of the Clk mutants results from decreased production of ROS, we examined sensitivity to oxidative stress and oxidative damage. We found no evidence for systematically increased resistance to oxidative stress or decreased oxidative damage in the Clk mutants despite normal or elevated levels of superoxide dismutases. Overall, our findings suggest that decreased energy metabolism can lead to increased life span without decreased production of ROS. PMID:20382831
The importance of adult life-span perspective in explaining variations in political ideology.
Sedek, Grzegorz; Kossowska, Malgorzata; Rydzewska, Klara
As a comment on Hibbing et al.'s paper, we discuss the evolution of political and social views from more liberal to more conservative over the span of adulthood. We show that Hibbing et al.'s theoretical model creates a false prediction from this developmental perspective, as increased conservatism in the adult life-span trajectory is accompanied by the avoidance of negative bias. PMID:24970451
Mathematical basis of idea that harmonious marriage can lengthen life-span
Zhi-qiang Zhang
It is a very important issue for us to explore the effects of the marriage to life. In recent years, many scholars have proved\\u000a that the marriage can lengthen life-span from different angles. With the development of theory of dependence random variables,\\u000a we discuss the effects of the marriage to life and provide a mathematical basis of the idea that
Learning From Leaders: Life-span Trends in Olympians and Supercentenarians.
Antero-Jacquemin, Juliana da Silva; Berthelot, Geoffroy; Marck, Adrien; Noirez, Philippe; Latouche, Aurķlien; Toussaint, Jean-Franńois
Life-span trends progression has worldwide practical implications as it may affect the sustainability of modern societies. We aimed to describe the secular life-span trends of populations with a propensity to live longer-Olympians and supercentenarians-under two hypotheses: an ongoing life-span extension versus a biologic "probabilistic barrier" limiting further progression. In a study of life-span densities (total number of life durations per birth date), we analyzed 19,012 Olympians and 1,205 supercentenarians deceased between 1900 and 2013. Among most Olympians, we observed a trend toward increased life duration. This trend, however, decelerates at advanced ages leveling off with the upper values with a perennial gap between Olympians and supercentenarians during the whole observation period. Similar tendencies are observed among supercentenarians, and over the last years, a plateau attests to a stable longevity pattern among the longest-lived humans. The common trends between Olympians and supercentenarians indicate similar mortality pressures over both populations that increase with age, scenario better explained by a biologic "barrier" forecast. PMID:25143003
Learning From Leaders: Life-span Trends in Olympians and Supercentenarians
Berthelot, Geoffroy; Marck, Adrien; Noirez, Philippe; Latouche, Aurķlien; Toussaint, Jean-Franńois
Life-span trends progression has worldwide practical implications as it may affect the sustainability of modern societies. We aimed to describe the secular life-span trends of populations with a propensity to live longerŚOlympians and supercentenariansŚunder two hypotheses: an ongoing life-span extension versus a biologic ōprobabilistic barrierö limiting further progression. In a study of life-span densities (total number of life durations per birth date), we analyzed 19,012 Olympians and 1,205 supercentenarians deceased between 1900 and 2013. Among most Olympians, we observed a trend toward increased life duration. This trend, however, decelerates at advanced ages leveling off with the upper values with a perennial gap between Olympians and supercentenarians during the whole observation period. Similar tendencies are observed among supercentenarians, and over the last years, a plateau attests to a stable longevity pattern among the longest-lived humans. The common trends between Olympians and supercentenarians indicate similar mortality pressures over both populations that increase with age, scenario better explained by a biologic ōbarrierö forecast. PMID:25143003
Thioredoxin 1 Overexpression Extends Mainly the Earlier Part of Life Span in Mice
Pķrez, Viviana I.; Cortez, Lisa A.; Lew, Christie M.; Rodriguez, Marisela; Webb, Celeste R.; Van Remmen, Holly; Chaudhuri, Asish; Qi, Wenbo; Lee, Shuko; Bokov, Alex; Fok, Wilson; Jones, Dean; Richardson, Arlan; Yodoi, Junji; Zhang, Yiqiang; Tominaga, Kaoru; Hubbard, Gene B.
We examined the effects of increased levels of thioredoxin 1 (Trx1) on resistance to oxidative stress and aging in transgenic mice overexpressing Trx1 [Tg(TRX1)+/0]. The Tg(TRX1)+/0 mice showed significantly higher Trx1 protein levels in all the tissues examined compared with the wild-type littermates. Oxidative damage to proteins and levels of lipid peroxidation were significantly lower in the livers of Tg(TRX1)+/0 mice compared with wild-type littermates. The survival study demonstrated that male Tg(TRX1)+/0 mice significantly extended the earlier part of life span compared with wild-type littermates, but no significant life extension was observed in females. Neither male nor female Tg(TRX1)+/0 mice showed changes in maximum life span. Our findings suggested that the increased levels of Trx1 in the Tg(TRX1)+/0 mice were correlated to increased resistance to oxidative stress, which could be beneficial in the earlier part of life span but not the maximum life span in the C57BL/6 mice. PMID:21873593
The effect of parabiosis on life-span of rats stressed by radiation.
Warren, S; Chute, R N; Porter, M W
The life-spans of four series of NEDH rats were compared: (1) single control rats, (2) single rats irradiated with 1000 R, (3) control parabiont rats, (4) parabiont rats one of which had received 1000 R. The stress of radiation (1000 R) produced a median life shortening of 571 days in single rats. Parabiosis followed by irradiation (1000 R) of a member of the pair shortened life 132 days. Parabiosis alone produced a median life shortening of 62 days. Ninety percent of the older irradiated parabiont pairs died with one or more tumors present. Parabiosis largely protected animals from the gastrointestinal radiation syndrome. PMID:1109387
Role of cellular mechanics in the function and life span of vascular endothelium
Katrin Kliche; Pia Jeggle; Hermann Pavenstõdt; Hans Oberleithner
The vascular endothelium plays a crucial role in vessel homeostasis and is implicated in the pathogenesis of cardiovascular\\u000a disease. The function and life span of endothelial cells, therefore, have a large impact upon the quality and expectancy of\\u000a an individualÆs life. Exposure to haemodynamic forces determines the phenotype of endothelial cells. Turbulent blood flow,\\u000a disturbed shear stress and a rising
ETS4 Is a Transcriptional Regulator of Life Span in Caenorhabditis elegans
Bargavi Thyagarajan; Adam G. Blaszczak; Katherine J. Chandler; Jennifer L. Watts; W. Evan Johnson; Barbara J. Graves
Aging is a complex phenotype responsive to a plethora of environmental inputs; yet only a limited number of transcriptional regulators are known to influence life span. How the downstream expression programs mediated by these factors (or others) are coordinated into common or distinct set of aging effectors is an addressable question in model organisms, such as C. elegans. Here, we
Cellular proliferative capacity and life span in small and large dogs.
Li, Y; Deeb, B; Pendergrass, W; Wolf, N
In a study comparing animal life spans and in vitro clonal proliferative capacity of skin fibroblasts in groupings of small, middle, large, and very large breeds of dogs of specific ages, the following results were obtained: (1) their life spans were inversely correlated to the frame sizes of the breeds; (2) the percent of large clones present in clone size distributions from the small dogs was inversely proportional to the age of the subjects (this was not true for the large breeds; however, animals older than 8 years were not available in those breeds); and (3) the group composed of the two largest breeds (Great Dane and Irish Wolfhound) had the shortest life spans and also had significantly smaller percentages of large skin fibroblast clones formed in vitro than either of the two groupings of smaller dogs at any age studied. It appears that within the domestic dogs the large body size is accompanied by shorter life span and, in the two largest breeds, decreased cellular growth potential. PMID:8914489
Age, growth and size interact with stress to determine life span and mortality
Roach, Deborah Ann
Individuals in a large experimental field population, of the short-lived perennial species Plantago lanceolata, were followed to determine the sources of variation that influence mortality and life span. The design included multiple age groups with initially similar genetic structure, which made it possible to separate age effects from period effects and to identify the genetic component to variation in life span. During a period of stress, individuals of all ages showed parallel increases in mortality but different cohorts experienced this period of high mortality at different ages. This then influenced the distribution of life spans across cohorts. Age and size-age interactions influenced mortality during the period of stress. Smaller individuals died but only if they were old. Additionally, growth and age interacted with stress such that older individuals had negative growth and high mortality whereas younger individuals had positive growth and relatively lower mortality during stress. The results of this study show that it is not simply the environment that can have a major impact on demography in natural populations, rather, age, size and growth can interact with the environment to influence mortality and life span when the environment is stressful. PMID:22664575
Cancer risk among atomic bomb survivors. The RERF Life Span Study. Radiation Effects Research Foundation
Y. Shimizu; W. J. Schull; H. Kato
This article summarizes the risk of cancer among the survivors of the atomic bombing of Hiroshima and Nagasaki. We focus primarily on the risk of death from cancer among individuals in the Life Span Study sample of the Radiation Effects Research Foundation from 1950 through 1985 based on recently revised dosimetry procedures. We report the risk of cancer other than
Psychopathology in Williams Syndrome: The Effect of Individual Differences across the Life Span
ERIC Educational Resources Information Center
Dodd, Helen F.; Porter, Melanie A.
This research aimed to comprehensively explore psychopathology in Williams syndrome (WS) across the life span and evaluate the relationship between psychopathology and age category (child or adult), gender, and cognitive ability. The parents of 50 participants with WS, ages 6-50 years, were interviewed using the Schedule for Affective Disordersģ
Jennifer M. Withington; Peter B. Reich; Jacek Oleksyn; David M. Eissenstat
Global data sets provide strong evidence of convergence for leaf structure with leaf longevity such that species having thick leaves, low specific leaf area, low mass-based nitrogen concentrations, and low photosynthetic rates typically exhibit long leaf life span. Leaf longevity and corresponding leaf structure have also been widely linked to plant potential growth rate, plant competition, and nutrient cycling. We
The Understanding of Death and Dying in a Life-Span Perspective.
ERIC Educational Resources Information Center
de Vries, Brian; And Others
Individuals (n=54) from across adult life span wrote essays about death and dying. Examined extent to which essays were concerned with death or dying and self, others, or more abstract conceptions, as well as level of impact, involvement, and acceptance. Discussions of death were more frequent and more complex than discussions of dying.ģ
Adolescents' Ideas of Normative Life Span Development and Personal Future Goals.
ERIC Educational Resources Information Center
Malmberg, Lar-Erik; Norrgard, Sonja
Presents study results that supports relationship between individual goals and normative expectations about life span development, especially when it comes to domains of education, occupation, and family. Reports that respondents showed an awareness of the accumulation of social problems. Adolescents rated their future as better than the future ofģ
Asynchronous Vowel-Pair Identification across the Adult Life Span for Monaural and Dichotic Presentations
ERIC Educational Resources Information Center
Fogerty, Daniel; Kewley-Port, Diane; Humes, Larry E.
Purpose: Temporal order abilities decrease with age. Declining temporal processing abilities may influence the identification of rapid vowel sequences. Identification patterns for asynchronous vowel pairs were explored across the life span. Method: Young, middle-aged, and older listeners completed temporal order tasks for pairs of 70-ms and 40-msģ
Life-Span Analyses of Piagetian Concept Tasks: The Search for Nontrivial Qualitative Change.
ERIC Educational Resources Information Center
Hooper, Frank H.
The implications of a life-span developmental prospective for Piagetian theory and research are discussed in this paper. Initially, certain recent criticisms of the Piagetian system are evaluated. These include the interpretations of Piaget's abstract model of logical reasoning; his views concerning the interrelationship of hereditary,ģ
Developmental Change in Proactive Interference across the Life Span: Evidence from Two Working Memory Tasks
ERIC Educational Resources Information Center
Loosli, Sandra V.; Rahm, Benjamin; Unterrainer, Josef M.; Weiller, Cornelius; Kaller, Christoph P.
Working memory (WM) as the ability to temporarily maintain and manipulate various kinds of information is known to be affected by proactive interference (PI) from previously relevant contents, but studies on developmental changes in the susceptibility to PI are scarce. In the present study, we investigated life span development of item-specificģ
Age, growth and size interact with stress to determine life span and mortality.
Roach, Deborah Ann
Individuals in a large experimental field population, of the short-lived perennial species Plantago lanceolata, were followed to determine the sources of variation that influence mortality and life span. The design included multiple age groups with initially similar genetic structure, which made it possible to separate age effects from period effects and to identify the genetic component to variation in life span. During a period of stress, individuals of all ages showed parallel increases in mortality but different cohorts experienced this period of high mortality at different ages. This then influenced the distribution of life spans across cohorts. Age and size-age interactions influenced mortality during the period of stress. Smaller individuals died but only if they were old. Additionally, growth and age interacted with stress such that older individuals had negative growth and high mortality whereas younger individuals had positive growth and relatively lower mortality during stress. The results of this study show that it is not simply the environment that can have a major impact on demography in natural populations; rather, age, size and growth can interact with the environment to influence mortality and life span when the environment is stressful. PMID:22664575
Gains and Losses in Creative Personality as Perceived by Adults across the Life Span
ERIC Educational Resources Information Center
Hui, Anna N. N.; Yeung, Dannii Y.; Sue-Chan, Christina; Chan, Kara; Hui, Desmond C. K.; Cheng, Sheung-Tak
In this study, we used a life span model to study the subjective perception of creative personality (CP) in emerging, young, middle-aged, and older Hong Kong Chinese adults. We also asked participants to estimate the approximate age by which people develop and lose CP across adulthood. We expected an interesting interplay between internalized ageģ
Target of Rapamycin Signaling Regulates Metabolism, Growth, and Life Span in Arabidopsis[W][OA
Ren, Maozhi; Venglat, Prakash; Qiu, Shuqing; Feng, Li; Cao, Yongguo; Wang, Edwin; Xiang, Daoquan; Wang, Jinghe; Alexander, Danny; Chalivendra, Subbaiah; Logan, David; Mattoo, Autar; Selvaraj, Gopalan; Datla, Raju
Target of Rapamycin (TOR) is a major nutrition and energy sensor that regulates growth and life span in yeast and animals. In plants, growth and life span are intertwined not only with nutrient acquisition from the soil and nutrition generation via photosynthesis but also with their unique modes of development and differentiation. How TOR functions in these processes has not yet been determined. To gain further insights, rapamycin-sensitive transgenic Arabidopsis thaliana lines (BP12) expressing yeast FK506 Binding Protein12 were developed. Inhibition of TOR in BP12 plants by rapamycin resulted in slower overall root, leaf, and shoot growth and development leading to poor nutrient uptake and light energy utilization. Experimental limitation of nutrient availability and light energy supply in wild-type Arabidopsis produced phenotypes observed with TOR knockdown plants, indicating a link between TOR signaling and nutrition/light energy status. Genetic and physiological studies together with RNA sequencing and metabolite analysis of TOR-suppressed lines revealed that TOR regulates development and life span in Arabidopsis by restructuring cell growth, carbon and nitrogen metabolism, gene expression, and rRNA and protein synthesis. Gain- and loss-of-function Ribosomal Protein S6 (RPS6) mutants additionally show that TOR function involves RPS6-mediated nutrition and light-dependent growth and life span in Arabidopsis. PMID:23275579
Marital, reproductive, and educational behaviors covary with life expectancy.
Krupp, Daniel Brian
Theories of "life history evolution" suggest that individuals might adjust the timing of marriage and reproduction, as well as their propensity to terminate a marriage or pregnancy and invest in skill development, in response to indicators of the locally prevailing level of life expectancy. In particular, such theories generate the hypothesis that foreshortened time horizons lead to hastened reproduction and marriage whereas lengthier time horizons increase the likelihood of reproductive and marital termination and lead to greater investment in education. Here, I show that the scheduling and occurrence of marital and reproductive behavior (including both initiation and termination), as well as levels of educational attainment and investment, covary with life expectancy, even after controlling for the effects of affluence. In analyses of variation in marital, reproductive, and educational behaviors at two jurisdictional levels in Canada, life expectancy was positively correlated with patterns of age-specific fertility, age at first marriage, divorce, abortion, conferral of high school and higher education degrees (with the exception of the trades) and mean number of years of schooling. The large and highly consistent relationships observed between life expectancy and the behaviors under investigation suggest that these associations may be mediated by individual "perceptions" of life expectancy, though more research is needed before conclusions can be firmly reached. PMID:22484517
Effect of habitat preference on frond life span in three Cyathea tree ferns
NASA Astrophysics Data System (ADS)
Chiu, Tzu Yun; Wang, Hsiang Hua; Lun Kuo, Yao; Kume, Tomonori
It has been reported that plants living in various geographical areas had different physiological forms, as factors of microenvironment have strong impacts on physiological characters. However, the physiological characters of fronds have been scarcely reported in ferns. In this study, we investigated physiological differences in response to the habitat preference in the three tree ferns in northeast Taiwan, Cyathea lepifera, C. spinulosa, and C. podophylla, prefer to open site, edge of forest, and interior forest, respectively. The canopy openness above the individuals of C. lepifera, C. spinulosa and C. podophylla were 29.2 ▒ 14.10 , 7.0 ▒ 3.07 and 5.0 ▒ 2.24 %, respectively. Among three species, C. podophylla had the longest frond life span (13.0 ▒ 4.12 months) than the two others (C. lepifera (6.8 ▒ 1.29 months) and C. spinulosa (7.3 ▒1.35 months). Our result supported the general patterns that shade intolerant species have a shorter leaf life span than shade tolerant species. The maximum net CO2 assimilation of C. lepifera, C. spinulosa and C. podophylla were 11.46 ▒ 1.34, 8.27 ▒ 0.69, and 6.34 ▒ 0.54 ?mol CO2 m-2 s-1, respectively. As well, C. lepifera had the highest photosynthetic light saturation point (LSP), while C. podophylla had the lowest LSP among these three tree ferns. These suggested that C. lepifera could be more efficient for capturing and utilizing light resources under the larger canopy openness condition than the other two species. We also found that frond C : N ratio were positively correlated with frond life span among species. C. podophylla, with the longest frond life span, had the highest frond C : N ratio (22.17 ▒ 1.95), which was followed by C. spinulosa (18.58 ▒ 1.37) and C. lepifera (18.68 ▒ 2.63) with shorter frond life span. The results were consistent to the theory that the fronds and leaves of shade intolerant species have high photosynthetic abilities with low C : N ratio. Key words: Canopy openness, frond life span, tree fern, Cyathea, frond C : N ratio
Causes and consequences of variation in conifer leaf life-span
Reich, P.B.; Koike, T.; Gower, S.T.; Schoettle, A.W.
Species with mutually supporting traits, such as high N{sub mass}, SLA, and A{sub mass}, and short leaf life-span, tend to inhabit either generally resource-rich environments or spatial and/or temporal microhabitats that are resource-rich in otherwise more limited habitats (e.g., {open_quotes}precipitation{close_quotes} ephemerals in warm deserts or spring ephemerals in the understory of temperate deciduous forests). In contrast, species with long leaf life-span often support foliage with low SLA, N{sub mass}, and A{sub mass}, and often grow in low-temperature limited, dry, and/or nutrient-poor environments. The contrast between evergreen and deciduous species, and the implications that emerge from such comparisons, can be considered a paradigm of modern ecological theory. However, based on the results of Reich et al. (1992) and Gower et al. (1993), coniferous species with foliage that persists for 9-10 years are likely to assimilate and allocate carbon and nutrients differently than other evergreen conifers that retain foliage for 2-3 years. Thus, attempts to contrast ecophysiological or ecosystem characteristics of evergreen versus deciduous life forms may be misleading, and pronounced differences among evergreen conifers may be ignored. Clearly, the deciduous-evergreen contrast, although useful in several ways, should be viewed from the broader perspective of a gradient in leaf life-span.
Interaction Between the oxa1 and rmp1 Genes Modulates Respiratory Complex Assembly and Life Span in Podospora anserina
Carole H. Sellem; Claire Lemaire; Severine Lorin; Genevieve Dujardin; Annie Sainsard-Chanet
A causal link between deficiency of the cytochrome respiratory pathway and life span was previously shown in the filamentous fungus Podospora anserina. To gain more insight into the relationship between mitochondrial function and life span, we have constructed a strain carrying a thermosensitive mutation of the gene oxa1. OXA1 is a membrane protein conserved from bacteria to human. The mitochondrial
Reproductive and early life stages pathology - Histopathology workshop report
Bruno, D.W.; Nowak, B.; Elliott, D.G.
Pathology occurring during reproduction and larval development represents an important part of the life cycle of fish, and the diseases that affect eggs and larvae often result in significant losses. However, mortality during this period is frequently ignored or poorly researched as the temptation is to replace the losses rather than investigate the causes. A histopathology workshop organised at the newly refurnished laboratory within the Danish Veterinary School was an opportunity to discuss the pathology of selected diseases associated with Reproductive and Early Life Stages Pathology. Several people also kindly provided reference slides.
Life span of C57 mice as influenced by radiation dose, dose rate, and age at exposure
Spalding, J.F.; Thomas, R.G.; Tietjen, G.L.
This study was designed to measure the life shortening of C57BL/6J male mice as a result of exposure to five external doses from /sup 60/Co gamma radiation delivered at six different dose rates. Total doses ranged from 20 to 1620 rad at exposure rates ranging from 0.7 to 36,000 R/day. The ages of the mice at exposure were newborn, 2, 6, or 15 months. Two replications were completed. Although death was the primary endpoint, we did perform gross necropsies. The life span findings are variable, but we found no consistent shortening compared to control life spans. Therefore, we cannot logically extrapolate life shortening to lower doses, from the data we have obtained. In general, the younger the animals were at the beginning of exposure, the longer their life spans were compared to those of controls. This relationship weakened at the higher doses and dose rates, as mice in these categories tended not to have significantly different life spans from controls. Using life span as a criterion, we find this study suggests that some threshold dosage may exist beyond which effects of external irradiation may be manifested. Up to this threshold, there is no shortening effect on life span compared to that of control mice. Our results are in general agreement with the results of other researchers investigating human and other animal life span effects on irradiation.
Drosophila life span and physiology are modulated by sexual perception and reward.
Gendron, Christi M; Kuo, Tsung-Han; Harvanek, Zachary M; Chung, Brian Y; Yew, Joanne Y; Dierick, Herman A; Pletcher, Scott D
Sensory perception can modulate aging and physiology across taxa. We found that perception of female sexual pheromones through a specific gustatory receptor expressed in a subset of foreleg neurons in male fruit flies, Drosophila melanogaster, rapidly and reversibly decreases fat stores, reduces resistance to starvation, and limits life span. Neurons that express the reward-mediating neuropeptide F are also required for pheromone effects. High-throughput whole-genome RNA sequencing experiments revealed a set of molecular processes that were affected by the activity of the longevity circuit, thereby identifying new candidate cell-nonautonomous aging mechanisms. Mating reversed the effects of pheromone perception; therefore, life span may be modulated through the integrated action of sensory and reward circuits, and healthy aging may be compromised when the expectations defined by sensory perception are discordant with ensuing experience. PMID:24292624
A survey of automatic teller machine usage across the adult life span.
Rogers, W A; Cabrera, E F; Walker, N; Gilbert, D K; Fisk, A D
The purpose of this study was to analyze automatic teller machine (ATM) usage across the adult life span. We conducted an extensive survey of 9000 people in the Memphis and Atlanta metropolitan areas. Approximately 17% of those people responded. The survey assessed detailed demographic information, experience with technology in general, experience specifically related to ATMs, problems and dislikes with ATMs, and reasons that people do not use ATMs. The survey provided a valuable set of data. First, we have detailed information about the demographics and individual characteristics of ATM users and nonusers; importantly, these data are stratified across the adult life span. In addition, we know the likes and dislikes of ATM users and the types of problems they typically have using ATMs. Moreover, we have detailed analysis of why adults of all ages may choose not to use ATMs. Training and design implications of these data are discussed. PMID:8682517
Increased aerobic metabolism is essential for the beneficial effects of caloric restriction on yeast life span
Graciele A. Oliveira; Erich B. Tahara; Andreas K. Gombert; Mario H. Barros; Alicia J. Kowaltowski
Calorie restriction is a dietary regimen capable of extending life span in a variety of multicellular organisms. A yeast model\\u000a of calorie restriction has been developed in which limiting the concentration of glucose in the growth media of Saccharomyces cerevisiae leads to enhanced replicative and chronological longevity. Since S. cerevisiae are Crabtree-positive cells that present repression of aerobic catabolism when
Molecular and genetic analyses of a multivariate system specifying behavior and life span
Thomas E. Johnson
Recombinant inbred (RI) lines have been constructed by crossing the Bristol and Bergerac BO strains of the nematodeCaenorhabditis elegans. The F1 hermaphroditic progeny are allowed to self-fertilize for 20 generations, yielding the RI lines. Heritability estimates for several behavioral traits and for life span, as well as both phenotypic and genetic covariance estimates for these traits, have been obtained. Significant
CD4 memory T cell levels predict life span in genetically heterogeneous mice
Aging leads to changes in the relative proportions of several functionally distinct T cell sub- sets, including increases in the proportions of mem- ory cells in the CD4 and CD8 subsets and in the proportion of T cells expressing the multiple-drug resistance pump P-glycoprotein. To see whether in- dividual differences in T cell subset levels predict life span, we measured
Regulation of Drosophila Life Span by Olfaction and Food-Derived Odors
Sergiy Libert; Jessica Zwiener; Xiaowen Chu; Wayne VanVoorhies; Gregg Roman; Scott D. Pletcher
Smell is an ancient sensory system present in organisms from bacteria to humans. In the nematode Caeonorhabditis elegans, gustatory and olfactory neurons regulate aging and longevity. Using the fruit fly, Drosophila melanogaster, we showed that exposure to nutrient-derived odorants can modulate life span and partially reverse the longevity-extending effects of dietary restriction. Furthermore, mutation of odorant receptor Or83b resulted in
Dependence of the life span of the honeybee ( Apis mellifica ) upon flight performance and energy consumption
Angelika Neukirch
The life span of worker-honeybees is determined by the duration of the hive-period and of the foraging period (Figs. 1,2). The duration of the forgaing period is regulated in the following way: Total flight performance of the individual bee seems to be fixed. Daily flight performance strongly affects total flight duration. High daily flight performance decreases maximal flight duration and
C. elegans tubby regulates life span and fat storage by two independent mechanisms
Arnab Mukhopadhyay; Bart Deplancke; Albertha J. M. Walhout; Heidi A. Tissenbaum
In C. elegans, similar to in mammals, mutations in the tubby homolog, tub-1, promote increased fat deposition. Here, we show that mutation in tub-1 also leads to life span extension dependent on daf-16\\/FOXO. Interestingly, function of tub-1 in fat storage is independent of daf-16. A yeast two-hybrid screen identified a novel TUB-1 interaction partner (RBG-3); a RabGTPase-activating protein. Both TUB-1
Life span of solutions to a nonlocal in time nonlinear fractional Schr÷dinger equation
NASA Astrophysics Data System (ADS)
Kirane, M.; Nabti, A.
In this paper, we study the initial value problem for the nonlocal in time nonlinear Schr÷dinger equation iut+? u = ? J^{?}_{0\\vert t} \\vert u\\vert^p, quad x in {R}^N, quad t > 0, u(x,0) = f(x), quad x in {R}^N.quad quad Using the test function method, we derive a blow-up exponent. Then based on integral inequalities, we estimate the life span of blowing-up solutions.
Life Satisfaction, Self-Esteem, and Subjective Age in Women across the Life Span
ERIC Educational Resources Information Center
Borzumato-Gainey, Christine; Kennedy, Alison; McCabe, Beth; Degges-White, Suzanne
A study of 320 women, ages 21 to 69, explored the relations among relationship status, subjective age, self-esteem, and life satisfaction. Women in married or partnered relationships had higher levels of life satisfaction than did single women. Women in their 30s and 40s had significantly lower levels of life satisfaction than did other ageģ
Shorter Life Span of Microorganisms and Plants as a Consequence of Shielded Magnetic Environment
NASA Astrophysics Data System (ADS)
Dobrota, C.; Piso, I. M.; Bathory, D.
The geomagnetic field is an essential environmental factor for life and health on this planet. In order to survey how magnetic fields affect the life span and the nitrogenase (an iron-sulphur enzyme) activity of Azotobacter chroococcum as well as the life span, the main organic synthesis and the water balance of plants (22 species), the biological tests were incubated under shielded magnetic field and also in normal geo-magnetic environment. The shielding level was about 10-6 of the terrestrial magnetic field.Life cycles of all organisms require the co-ordinated control of a complex set of interlocked physiological processes and metabolic pathways. Such processes are likely to be regulated by a large number of genes. Our researches suggest that the main point in biological structures, which seems to be affected by the low magnetic environment, is the water molecule. Magnetic field induces a molecular alignment. Under shielded conditions, unstructured water molecules with fewer hydrogen bonds, which are producing a more reactive environment, are occurring. As compared to control, the life span of both microorganisms and plants was shorter in shielded environment. A higher nitrogenase affinity for the substrate was recorded in normal geo-magnetic field compared to low magnetic field. The synthesis of carbohydrates, lipids, proteins and enzymes was modified under experimental conditions. The stomatal conductance was higher between 158 and 300% in shielded environment indicating an important water loss from the plant cells.Our results support the idea that the shielded magnetic environment induces different reactions depending on the time of exposure and on the main metabolic pathways of the cells.
Formal Models of Reproduction: from Computer Viruses to Artificial Life
Atkinson, Katie
Formal Models of Reproduction: from Computer Viruses to Artificial Life Thesis submitted. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.1 Motivations of Computer Virus Writers . . . . . . . . . . . . . . 2 1.1.2 A Short History of Computer Viruses . . . . . . . . . . . . . . . 3 1.1.3 Academic Study of Computer Viruses
Evolution, reproduction and definition of life.
Chodasewicz, Krzysztof
Synthetic theory of evolution is a superior integrative biological theory. Therefore, there is nothing surprising about the fact that multiple attempts of defining life are based on this theory. One of them even has a status of NASA's working definition. According to this definition, 'life is a self-sustained chemical system capable of undergoing Darwinian evolution' Luisi (Orig Life Evol Bios 28:613-622, 1998); Cleland, Chyba (Orig Life Evol Bios 32:387-393, 2002). This definition is often considered as one of the more theoretically mature definitions of life. This Darwinian definition has nonetheless provoked a lot of criticism. One of the major arguments claims that this definition is wrong due to 'mule's problem'. Mules (and other infertile hybrids), despite being obviously living organisms, in the light of this definition are considered inanimate objects. It is strongly counterintuitive. The aim of this article was to demonstrate that this reasoning is false. In the later part of the text, I also discuss some other arguments against the Darwinian approach to defining life. PMID:23674095
The life span-prolonging effect of sirtuin-1 is mediated by autophagy.
Morselli, Eugenia; Maiuri, Maria Chiara; Markaki, Maria; Megalou, Evgenia; Pasparaki, Angela; Palikaras, Konstantinos; Criollo, Alfredo; Galluzzi, Lorenzo; Malik, Shoaib Ahmad; Vitale, Ilio; Michaud, Mickael; Madeo, Frank; Tavernarakis, Nektarios; Kroemer, Guido
The life span of various model organisms can be extended by caloric restriction as well as by autophagy-inducing pharmacological agents. Life span-prolonging effects have also been observed in yeast cells, nematodes and flies upon the overexpression of the deacetylase Sirtuin-1. Intrigued by these observations and by the established link between caloric restriction and Sirtuin-1 activation, we decided to investigate the putative implication of Sirtuin-1 in the response of human cancer cells and Caenorhabditis elegans to multiple triggers of autophagy. Our data indicate that the activation of Sirtuin-1 (by the pharmacological agent resveratrol and/or genetic means) per se ignites autophagy, and that Sirtuin-1 is required for the autophagic response to nutrient deprivation, in both human and nematode cells, but not for autophagy triggered by downstream signals such as the inhibition of mTOR or p53. Since the life spanextending effects of Sirtuin-1 activators are lost in autophagy-deficient C. elegans, our results suggest that caloric restriction and resveratrol extend longevity, at least in experimental settings, by activating autophagy. PMID:20023410
Resveratrol Attenuates Oxidative Stress and Extends Life Span in the Annual Fish Nothobranchius guentheri.
Liu, Tingting; Qi, He; Ma, Long; Liu, Zhaojun; Fu, Huiling; Zhu, Wenzhen; Song, Taiyu; Yang, Bingwu; Li, Guorong
Resveratrol is a natural polyphenol derived mainly from the skin of grapes and from red wine. Resveratrol prolongs life span in several invertebrates, but this function is not found in mice. Our recently published paper demonstrated that resveratrol prolonged longevity of the annual fish Nothobranchius guentheri, a promising vertebrate model for anti-aging research. However, the anti-aging process by resveratrol remains largely unexplored, and little is known about its effects on oxidative stress. In this study, by long-term supplementation of resveratrol from sexual maturity onward in the annual fish, we detected survivorship and oxidative stress at three different developmental stages in vivo. A total of 112 fish were fed with resveratrol in the concentration of 200??g/gram food and 111 fish without resveratrol from 16 weeks of age until to the end of their lives. The mean and maximum life spans of the fish treated with resveratrol were extended by 17.34% and 17.66%, respectively, compared to the fish in control group. The markers of oxidative stress, such as the levels of reactive oxygen species (ROS), the activities of anti-oxidant enzymes, and the degree of oxidative damage, were detected at 6, 9, and 12 months, respectively. The results showed that levels of ROS and oxidative damage increased and activities of anti-oxidant enzymes appeared to decrease with age. Resveratrol treatment significantly attenuated the increase of ROS and oxidative damage and up-regulated the decrease of anti-oxidant enzyme activities induced by aging. Our results demonstrated that resveratrol decreased oxidative stress and extended life span in this short-lived fish. PMID:25569124
Vasoprotective effects of life span-extending peripubertal GH replacement in Lewis dwarf rats.
Ungvari, Zoltan; Gautam, Tripti; Koncz, Peter; Henthorn, Jim C; Pinto, John T; Ballabh, Praveen; Yan, Han; Mitschelen, Matthew; Farley, Julie; Sonntag, William E; Csiszar, Anna
In humans, growth hormone deficiency (GHD) and low circulating levels of insulin-like growth factor 1 (IGF-1) significantly increase the risk for cerebrovascular disease. Genetic growth hormone (GH)/IGF-1 deficiency in Lewis dwarf rats significantly increases the incidence of late-life strokes, similar to the effects of GHD in elderly humans. Peripubertal treatment of Lewis dwarf rats with GH delays the occurrence of late-life stroke, which results in a significant extension of life span. The present study was designed to characterize the vascular effects of life span-extending peripubertal GH replacement in Lewis dwarf rats. Here, we report, based on measurements of dihydroethidium fluorescence, tissue isoprostane, GSH, and ascorbate content, that peripubertal GH/IGF-1 deficiency in Lewis dwarf rats increases vascular oxidative stress, which is prevented by GH replacement. Peripubertal GHD did not alter superoxide dismutase or catalase activities in the aorta nor the expression of Cu-Zn-SOD, Mn-SOD, and catalase in the cerebral arteries of dwarf rats. In contrast, cerebrovascular expression of glutathione peroxidase 1 was significantly decreased in dwarf vessels, and this effect was reversed by GH treatment. Peripubertal GHD significantly decreases expression of the Nrf2 target genes NQO1 and GCLC in the cerebral arteries, whereas it does not affect expression and activity of endothelial nitric oxide synthase and vascular expression of IGF-1, IGF-binding proteins, and inflammatory markers (tumor necrosis factor alpha, interluekin-6, interluekin-1?, inducible nitric oxide synthase, intercellular adhesion molecule 1, and monocyte chemotactic protein-1). In conclusion, peripubertal GH/IGF-1 deficiency confers pro-oxidative cellular effects, which likely promote an adverse functional and structural phenotype in the vasculature, and results in accelerated vascular impairments later in life. PMID:20713653
Increased iron supplied through Fet3p results in replicative life span extension of Saccharomyces cerevisiae under conditions requiring respiratory metabolism
Gabriela Botta; Christina S. Turn; Nicholas J. Quintyne; Paul A. Kirchman
We have previously shown that copper supplementation extends the replicative life span of Saccharomyces cerevisiae when grown under conditions forcing cells to respire. We now show that copper's effect on life span is through Fet3p, a copper containing enzyme responsible for high affinity transport of iron into yeast cells. Life span extensions can also be obtained by supplementing the growth
Reduced Ssy1-Ptr3-Ssy5 (SPS) Signaling Extends Replicative Life Span by Enhancing NAD+ Homeostasis in Saccharomyces cerevisiae.
Tsang, Felicia; James, Christol; Kato, Michiko; Myers, Victoria; Ilyas, Irtqa; Tsang, Matthew; Lin, Su-Ju
Attenuated nutrient signaling extends the life span in yeast and higher eukaryotes; however, the mechanisms are not completely understood. Here we identify the Ssy1-Ptr3-Ssy5 (SPS) amino acid sensing pathway as a novel longevity factor. A null mutation of SSY5 (ssy5?) increases replicative life span (RLS) by ?50%. Our results demonstrate that several NAD(+) homeostasis factors play key roles in this life span extension. First, expression of the putative malate-pyruvate NADH shuttle increases in ssy5? cells, and deleting components of this shuttle, MAE1 and OAC1, largely abolishes RLS extension. Next, we show that Stp1, a transcription factor of the SPS pathway, directly binds to the promoter of MAE1 and OAC1 to regulate their expression. Additionally, deletion of SSY5 increases nicotinamide riboside (NR) levels and phosphate-responsive (PHO) signaling activity, suggesting that ssy5? increases NR salvaging. This increase contributes to NAD(+) homeostasis, partially ameliorating the NAD(+) deficiency and rescuing the short life span of the npt1? mutant. Moreover, we observed that vacuolar phosphatase, Pho8, is partially required for ssy5?-mediated NR increase and RLS extension. Together, our studies present evidence that supports SPS signaling is a novel NAD(+) homeostasis factor and ssy5?-mediated life span extension is likely due to concomitantly increased mitochondrial and vacuolar function. Our findings may contribute to understanding the molecular basis of NAD(+) metabolism, cellular life span, and diseases associated with NAD(+) deficiency and aging. PMID:25825491
Career Adaptability: An Integrative Construct for Life-Span, Life-Space Theory.
ERIC Educational Resources Information Center
Savickas, Mark L.
Examines the origin and current status of lifespan, life-space theory and proposes one way in which to integrate its three segments. Discusses a functionalist strategy for theory construction and the outcomes and consequences of this strategy. Discusses future directions for theory development, such as career adaptability and planful attitudes.ģ
CALHM1 Deletion in Mice Affects Glossopharyngeal Taste Responses, Food Intake, Body Weight, and Life Span.
Hellekant, G÷ran; Schmolling, Jared; Marambaud, Philippe; Rose-Hellekant, Teresa A
Stimulation of Type II taste receptor cells (TRCs) with T1R taste receptors causes sweet or umami taste, whereas T2Rs elicit bitter taste. Type II TRCs contain the calcium channel, calcium homeostasis modulator protein 1 (CALHM1), which releases adenosine triphosphate (ATP) transmitter to taste fibers. We have previously demonstrated with chorda tympani nerve recordings and two-bottle preference (TBP) tests that mice with genetically deleted Calhm1 (knockout [KO]) have severely impaired perception of sweet, bitter, and umami compounds, whereas their sour and salty tasting ability is unaltered. Here, we present data from KO mice of effects on glossopharyngeal (NG) nerve responses, TBP, food intake, body weight, and life span. KO mice have no NG response to sweet and a suppressed response to bitter compared with control (wild-type [WT]) mice. KO mice showed some NG response to umami, suggesting that umami taste involves both CALHM1- and non-CALHM1-modulated signals. NG responses to sour and salty were not significantly different between KO and WT mice. Behavioral data conformed in general with the NG data. Adult KO mice consumed less food, weighed significantly less, and lived almost a year longer than WT mice. Taken together, these data demonstrate that sweet taste majorly influences food intake, body weight, and life span. PMID:25855639
CTT1 overexpression increases life span of calorie-restricted Saccharomyces cerevisiae deficient in Sod1.
Rona, Germana; Herdeiro, Ricardo; Mathias, Cristiane Juliano; Torres, Fernando Araripe; Pereira, Marcos Dias; Eleutherio, Elis
Studies using different organisms revealed that reducing calorie intake, without malnutrition, known as calorie restriction (CR), increases life span, but its mechanism is still unkown. Using the yeast Saccharomyces cerevisiae as eukaryotic model, we observed that Cu, Zn-superoxide dismutase (Sod1p) is required to increase longevity, as well as to confer protection against lipid and protein oxidation under CR. Old cells of sod1 strain also presented a premature induction of apoptosis. However, when CTT1 (which codes for cytosolic catalase) was overexpressed, sod1 and WT strains showed similar survival rates. Furthermore, CTT1 overexpression decreased lipid peroxidation and delayed the induction of apoptotic process. Superoxide is rapidly converted to hydrogen peroxide by superoxide dismutase, but it also undergoes spontaneous dismutation albeit at a slower rate. However, the quantity of peroxide produced from superoxide in this way is two-fold higher. Peroxide degradation, catalyzed by catalase, is of vital importance, because in the presence of a reducer transition metal peroxide is reduced to the highly reactive hydroxyl radical, which reacts indiscriminately with most cellular constituents. These findings might explain why overexpression of catalase was able to overcome the deficiency of Sod1p, increasing life span in response to CR. PMID:25573485
Mixed emotions across the adult life span in the United States.
Schneider, Stefan; Stone, Arthur A
Mixed emotions involve the co-occurrence of positive and negative affect, such that people feel happy and sad at the same time. The purpose of the present study was to investigate age-related differences in the experience of mixed emotions across the adult life span in 2 nationally representative samples of U.S. residents. Data collected by the Princeton Affect and Time Survey (PATS, n = 3,948) and by the 2010 Wellbeing Module of the American Time Use Survey (ATUS, n = 12,828) were analyzed. In both surveys, respondents (aged 15 years or older) provided a detailed time diary about the preceding day and rated their happiness and sadness for 3 of the day's episodes. From these reports, 3 different indices of mixed emotions were derived. Results indicated small, but robust, increases in mixed emotions with age. Linear age increases were consistently evident in both PATS and ATUS, and replicated across the different indices of mixed emotions. There was no significant evidence for curvilinear age trends in either study. Several sociodemographic factors that could plausibly explain age-differences in mixed emotions (e.g., retirement, disability) did not alter the age-effects. The present study adds to the growing literature documenting vital changes in the complexity of emotional experience over the life span. (PsycINFO Database Record PMID:25894487
Sex-linked Correlated Responses in Female Reproductive Traits to Selection on Male Eye Span in Stalk-eyed Flies.
Wilkinson, Gerald S; Amitin, Emily G; Johns, Philip M
Coevolution between male and female traits can result from correlated responses to selection or correlated selection on genetically independent traits. This study examines the possibility that traits involved in precopulatory sexual selection may influence the evolution of traits involved in postcopulatory sexual selection due to the existence of correlated selection or correlated responses to selection. Artificial selection on male eye span in Cyrtodiopsis dalmanni, a sexually dimorphic stalk-eyed fly, is used to test for correlated changes in reproductive traits of male and female flies. Flies from replicate lines that had been under selection for 57 generations were matched for age and genotyped at four X-linked microsatellite loci. Egg number and testis size increased with age, but did not differ among lines. Spermathecal areas and duct lengths differed among replicates, but not among selection treatments. Female relative eye span, size of the ventral receptacle and egg size exhibited significant correlated responses to selection on male relative eye span. The absence of any change in sperm length or testis size between lines indicates that changes in female traits are unlikely due to correlated selection mediated by sperm competition. Significant effects of X-linked microsatellite genotypes indicate instead that the correlated responses to selection were due, in part, to X-linked genes in linkage disequilibrium or that exhibit pleiotropy. The presence of nonadditive allelic effects on genetically correlated female traits combined with additive allelic effects on a male ornament provides a previously unrecognized mechanism by which genetic variation could be maintained despite strong sexual selection. PMID:21676795
Life history costs and consequences of rapid reproductive maturation in female rhesus macaques
Fred B. Bercovitch; John D. Berard
Life history theory suggests that reproduction at one point in time involves costs in terms of energy, reduced survival, or probability of reproduction at a future point in time. ln long-lived iteroparous organisms, initiating reproduction at a relatively young age may exact a cost in terms of reduced survivorship, but an early age of first reproduction could be beneficial if
High-frequency generation of conditional mutations affecting Drosophila melanogaster development and life span.
Landis, G; Bhole, D; Lu, L; Tower, J
Genome sequencing reveals that a large percentage of Drosophila genes have homologs in humans, including many human disease genes. The goal of this research was to develop methods to efficiently test Drosophila genes for functions in vivo. An important challenge is the fact that many genes function at more than one point during development and during the life cycle. Conditional expression systems such as promoters regulated by tetracycline (or its derivative doxycycline) are often ideal for testing gene functions. However, generation of transgenic animals for each gene of interest is impractical. Placing the doxycycline-inducible ("tet-on") promoter directed out of the end of the P transposable element produced a mobile, doxycycline-inducible promoter element, named PdL. PdL was mobilized to 228 locations in the genome and was found to generate conditional (doxycycline-dependent), dominant mutations at high frequency. The temporal control of gene overexpression allowed generation of mutant phenotypes specific to different stages of the life cycle, including metamorphosis and aging. Mutations characterized included inserts in the alpha-mannosidase II (dGMII), ash1, and pumilio genes. Novel phenotypes were identified for each gene, including specific developmental defects and increased or decreased life span. The PdL system should facilitate testing of a large fraction of Drosophila genes for overexpression and misexpression phenotypes at specific developmental and life cycle stages. PMID:11454765
High-frequency generation of conditional mutations affecting Drosophila melanogaster development and life span.
Landis, G; Bhole, D; Lu, L; Tower, J
Genome sequencing reveals that a large percentage of Drosophila genes have homologs in humans, including many human disease genes. The goal of this research was to develop methods to efficiently test Drosophila genes for functions in vivo. An important challenge is the fact that many genes function at more than one point during development and during the life cycle. Conditional expression systems such as promoters regulated by tetracycline (or its derivative doxycycline) are often ideal for testing gene functions. However, generation of transgenic animals for each gene of interest is impractical. Placing the doxycycline-inducible ("tet-on") promoter directed out of the end of the P transposable element produced a mobile, doxycycline-inducible promoter element, named PdL. PdL was mobilized to 228 locations in the genome and was found to generate conditional (doxycycline-dependent), dominant mutations at high frequency. The temporal control of gene overexpression allowed generation of mutant phenotypes specific to different stages of the life cycle, including metamorphosis and aging. Mutations characterized included inserts in the alpha-mannosidase II (dGMII), ash1, and pumilio genes. Novel phenotypes were identified for each gene, including specific developmental defects and increased or decreased life span. The PdL system should facilitate testing of a large fraction of Drosophila genes for overexpression and misexpression phenotypes at specific developmental and life cycle stages. PMID:11454765
Social network changes and life events across the life span: a meta-analysis.
Wrzus, Cornelia; Hõnel, Martha; Wagner, Jenny; Neyer, Franz J
For researchers and practitioners interested in social relationships, the question remains as to how large social networks typically are, and how their size and composition change across adulthood. On the basis of predictions of socioemotional selectivity theory and social convoy theory, we conducted a meta-analysis on age-related social network changes and the effects of life events on social networks using 277 studies with 177,635 participants from adolescence to old age. Cross-sectional as well as longitudinal studies consistently showed that (a) the global social network increased up until young adulthood and then decreased steadily, (b) both the personal network and the friendship network decreased throughout adulthood, (c) the family network was stable in size from adolescence to old age, and (d) other networks with coworkers or neighbors were important only in specific age ranges. Studies focusing on life events that occur at specific ages, such as transition to parenthood, job entry, or widowhood, demonstrated network changes similar to such age-related network changes. Moderator analyses detected that the type of network assessment affected the reported size of global, personal, and family networks. Period effects on network sizes occurred for personal and friendship networks, which have decreased in size over the last 35 years. Together the findings are consistent with the view that a portion of normative, age-related social network changes are due to normative, age-related life events. We discuss how these patterns of normative social network development inform research in social, evolutionary, cultural, and personality psychology. PMID:22642230
Biological impact of auditory expertise across the life span: musicians as a model of auditory learning
Strait, Dana L.; Kraus, Nina
Experience-dependent characteristics of auditory function, especially with regard to speech-evoked auditory neurophysiology, have garnered increasing attention in recent years. This interest stems from both pragmatic and theoretical concerns as it bears implications for the prevention and remediation of language-based learning impairment in addition to providing insight into mechanisms engendering experience-dependent changes in human sensory function. Musicians provide an attractive model for studying the experience-dependency of auditory processing in humans due to their distinctive neural enhancements compared to nonmusicians. We have only recently begun to address whether these enhancements are observable early in life, during the initial years of music training when the auditory system is under rapid development, as well as later in life, after the onset of the aging process. Here we review neural enhancements in musically trained individuals across the life span in the context of cellular mechanisms that underlie learning, identified in animal models. MusiciansÆ subcortical physiologic enhancements are interpreted according to a cognitive framework for auditory learning, providing a model by which to study mechanisms of experience-dependent changes in auditory function in humans. PMID:23988583
Life spans of a Bellman-Harris branching process with immigration
Badalbaev, I.S.; Mashrabbaev, A.
One considers two schemes of the Bellman-Harris process with immigration when a) the lifetime of the particles is an integral-valued random variable and the immigration is defined by a sequence of independent random variables; b) the distribution of the lifetime of the particles is nonlattice and the immigration is a process with continuous time. One investigates the properties of the life spans of such processes. The results obtained here are a generalization to the case of Bellman-Harris processes of the results of A.M. Zubkov, obtained for Markov branching processes. For the proof one makes use in an essential manner of the known inequalities of Goldstein, estimating the generating function of the Bellman-Harris process in terms of the generating functions of the imbedded Galton-Watson process.
Mitochondrial respiratory thresholds regulate yeast chronological life span and its extension by caloric restriction.
Ocampo, Alejandro; Liu, Jingjing; Schroeder, Elizabeth A; Shadel, Gerald S; Barrientos, Antoni
We have explored the role of mitochondrial function in aging by genetically and pharmacologically modifying yeast cellular respiration production during the exponential and/or stationary growth phases and determining how this affects chronological life span (CLS). Our results demonstrate that respiration is essential during both growth phases for standard CLS, but that yeast have a large respiratory capacity, and only deficiencies below a threshold (~40% of wild-type) significantly curtail CLS. Extension of CLS by caloric restriction also required respiration above a similar threshold during exponential growth and completely alleviated the need for respiration in the stationary phase. Finally, we show that supplementation of media with 1% trehalose, a storage carbohydrate, restores wild-type CLS to respiratory-null cells. We conclude that mitochondrial respiratory thresholds regulate yeast CLS and its extension by caloric restriction by increasing stress resistance, an important component of which is the optimal accumulation and mobilization of nutrient stores. PMID:22768839
Gas and dust emission from comets and life spans of active areas on their rotating nuclei
NASA Technical Reports Server (NTRS)
Sekanina, Z.
Outgassing and dust emission from discrete regions on the nuclei of comets are investigated with regard to the processes of activation, dormancy, reactivation, and extinction. With regard to P/Halley, P/Encke, P/Tempel 2, P/Machholz, P/Takamizawa, Bowell and some other new comets, the evolution of one active region of the nucleus surface appears to be independent of the evolution of another active region. The traditional concept of deactivation as a slow and monolithic process needs to be replaced with a more dynamic concept of intermittent periods of dormancy and reactivation of individual vents, varying in size. Life spans of discrete sources of activity are estimated to be at a few hundred revolutions about the sun for comets with perihelia at heliocentric distances of less than 2 AU, if the bulk density is very low.
Virtual navigation strategies from childhood to senescence: evidence for changes across the life span
Bohbot, Veronique D.; McKenzie, Sam; Konishi, Kyoko; Fouquet, Celine; Kurdi, Vanessa; Schachar, Russel; Boivin, Michel; Robaey, Philippe
This study sought to investigate navigational strategies across the life span, by testing 8-years old children to 80-years old healthy older adults on the 4 on 8 virtual maze (4/8VM). The 4/8VM was previously developed to assess spontaneous navigational strategies, i.e., hippocampal-dependent spatial strategies (navigation by memorizing relationships between landmarks) versus caudate nucleus-dependent response strategies (memorizing a series of left and right turns from a given starting position). With the 4/8VM, we previously demonstrated greater fMRI activity and gray matter in the hippocampus of spatial learners relative to response learners. A sample of 599 healthy participants was tested in the current study. Results showed that 84.4% of children, 46.3% of young adults, and 39.3% of older adults spontaneously used spatial strategies (p < 0.0001). Our results suggest that while children predominantly use spatial strategies, the proportion of participants using spatial strategies decreases across the life span, in favor of response strategies. Factors promoting response strategies include repetition, reward and stress. Since response strategies can result from successful repetition of a behavioral pattern, we propose that the increase in response strategies is a biological adaptive mechanism that allows for the automatization of behavior such as walking in order to free up hippocampal-dependent resources. However, the down-side of this shift from spatial to response strategies occurs if people stop building novel relationships, which occurs with repetition and routine, and thereby stop stimulating their hippocampus. Reduced fMRI activity and gray matter in the hippocampus were shown to correlate with cognitive deficits in normal aging. Therefore, these results have important implications regarding factors involved in healthy and successful aging. PMID:23162463
Dietary resveratrol prevents Alzheimer's markers and increases life span in SAMP8.
Porquet, David; Casades·s, Gemma; Bayod, Sergi; Vicente, Alberto; Canudas, Anna M; Vilaplana, Jordi; PelegrĒ, Carme; Sanfeliu, Coral; Camins, Antoni; PallÓs, MercĶ; del Valle, Jaume
Resveratrol is a polyphenol that is mainly found in grapes and red wine and has been reported to be a caloric restriction (CR) mimetic driven by Sirtuin 1 (SIRT1) activation. Resveratrol increases metabolic rate, insulin sensitivity, mitochondrial biogenesis and physical endurance, and reduces fat accumulation in mice. In addition, resveratrol may be a powerful agent to prevent age-associated neurodegeneration and to improve cognitive deficits in Alzheimer's disease (AD). Moreover, different findings support the view that longevity in mice could be promoted by CR. In this study, we examined the role of dietary resveratrol in SAMP8 mice, a model of age-related AD. We found that resveratrol supplements increased mean life expectancy and maximal life span in SAMP8 and in their control, the related strain SAMR1. In addition, we examined the resveratrol-mediated neuroprotective effects on several specific hallmarks of AD. We found that long-term dietary resveratrol activates AMPK pathways and pro-survival routes such as SIRT1 in vivo. It also reduces cognitive impairment and has a neuroprotective role, decreasing the amyloid burden and reducing tau hyperphosphorylation. PMID:23129026
The activity-dependent histone variant H2BE modulates the life span of olfactory neurons
Santoro, Stephen W; Dulac, Catherine
We have identified a replication-independent histone variant, Hist2h2be (referred to herein as H2be), which is expressed exclusively by olfactory chemosensory neurons. Levels of H2BE are heterogeneous among olfactory neurons, but stereotyped according to the identity of the co-expressed olfactory receptor (OR). Gain- and loss-of-function experiments demonstrate that changes in H2be expression affect olfactory function and OR representation in the adult olfactory epithelium. We show that H2BE expression is reduced by sensory activity and that it promotes neuronal cell death, such that inactive olfactory neurons display higher levels of the variant and shorter life spans. Post-translational modifications (PTMs) of H2BE differ from those of the canonical H2B, consistent with a role for H2BE in altering transcription. We propose a physiological function for H2be in modulating olfactory neuron population dynamics to adapt the OR repertoire to the environment. DOI: http://dx.doi.org/10.7554/eLife.00070.001 PMID:23240083
Resource allocation in a social wasp: effects of breeding system and life cycle on reproductive decisions
Yi, Soojin
Resource allocation in a social wasp: effects of breeding system and life cycle on reproductive resources to reproduction. We investigated allocation decisions in the social wasp Vespula maculifrons to understand how social insects make reproductive choices. We first determined how annual colonies apportioned
Using renal transplantation to evaluate a simple approach for predicting the impact of end-stage renal disease therapies on patient survival: Observed\\/expected life span
Bryan N. Becker; Yolanda T. Becker; Thomas J. Pintar; Bradley H. Collins; John D. Pirsch; Aaron Friedman; Hans W. Sollinger; Peter C. Brazy
The effectiveness of therapy for a chronic disease can be assessed by evaluating the length of time that a patient survives after receiving treatment. We used a novel means for measuring the effectiveness of renal replacement therapy for patients with end-stage renal disease (ESRD): the ratio of observed life span divided by expected life span. This ratio incorporated observed life
Association between life-span extension by caloric restriction and thiol redox state in two different strains of mice
Igor Rebrin; Michael J. Forster; Rajindar S. Sohal
The hypothesis that the life-extending effect of caloric restriction (CR) is associated with an attenuation of the age-related pro-oxidant shift in the thiol redox state was tested employing a novel experimental design. Amounts of GSH, GSSG, and protein mixed disulfides (Pr-SSG) in the skeletal muscle and liver were compared between two strains of mice that have similar life spans when
HIV1 dynamics in vivo: Virion clearance rate, infected cell life-span, and viral generation time
A. S. Perelson; A. U. Neumann; M. Markowitz; D. D. Ho; J. M. Leonard
A new mathematical model was used to analyze a detailed set of human immunodeficiency virus-type 1 (HIV-1) viral load data collected from five infected individuals after the administration of a potent inhibitor of HIV-1 protease. Productively infected cells were estimated to have, on average, a life-span of 2.2 days (half-life tŌüŌ = 1.6 days), and plasma virions were estimated to
Liver-specific ?-glutamyl carboxylase-deficient mice display bleeding diathesis and short life span.
Azuma, Kotaro; Tsukui, Tohru; Ikeda, Kazuhiro; Shiba, Sachiko; Nakagawa, Kimie; Okano, Toshio; Urano, Tomohiko; Horie-Inoue, Kuniko; Ouchi, Yasuyoshi; Ikawa, Masahito; Inoue, Satoshi
Vitamin K is a fat-soluble vitamin that plays important roles in blood coagulation and bone metabolism. One of its functions is as a co-factor for ?-glutamyl carboxylase (Ggcx). Conventional knockout of Ggcx causes death shortly after birth in homozygous mice. We created Ggcx-floxed mice by inserting loxP sequences at the sites flanking exon 6 of Ggcx. By mating these mice with albumin-Cre mice, we generated Ggcx-deficient mice specifically in hepatocytes (Ggcx(?liver/?liver) mice). In contrast to conventional Ggcx knockout mice, Ggcx(?liver/?liver) mice had very low activity of Ggcx in the liver and survived several weeks after birth. Furthermore, compared with heterozygous mice (Ggcx(+/?liver) ), Ggcx(?liver/?liver) mice had shorter life spans. Ggcx(?liver/?liver) mice displayed bleeding diathesis, which was accompanied by decreased activity of coagulation factors II and IX. Ggcx-floxed mice can prove useful in examining Ggcx functions in vivo. PMID:24520408
Childhood self-control and unemployment throughout the life span: evidence from two british cohort studies.
Daly, Michael; Delaney, Liam; Egan, Mark; Baumeister, Roy F
The capacity for self-control may underlie successful labor-force entry and job retention, particularly in times of economic uncertainty. Analyzing unemployment data from two nationally representative British cohorts (N = 16,780), we found that low self-control in childhood was associated with the emergence and persistence of unemployment across four decades. On average, a 1-SD increase in self-control was associated with a reduction in the probability of unemployment of 1.4 percentage points after adjustment for intelligence, social class, and gender. From labor-market entry to middle age, individuals with low self-control experienced 1.6 times as many months of unemployment as those with high self-control. Analysis of monthly unemployment data before and during the 1980s recession showed that individuals with low self-control experienced the greatest increases in unemployment during the recession. Our results underscore the critical role of self-control in shaping life-span trajectories of occupational success and in affecting how macroeconomic conditions affect unemployment levels in the population. PMID:25870404
Dietary Intake of Curcuma longa and Emblica officinalis Increases Life Span in Drosophila melanogaster
Rawal, Shilpa; Singh, Pavneet; Gupta, Ayush; Mohanty, Sujata
Intake of food and nutrition plays a major role in affecting aging process and longevity. However, the precise mechanisms underlying the ageing process are still unclear. To this respect, diet has been considered to be a determinant of ageing process. In order to better illustrate this, we used Drosophila melanogaster as a model and fed them orally with different concentrations of two commonly used Indian medicinal plant products, Curcuma longa (rhizome) and Emblica officinalis (fruit). The results revealed significant increase in life span of Drosophila flies on exposure to both the plant products, more efficiently by C. Longa than by E. officinalis. In order to understand whether the increase in lifespan was due to high-antioxidant properties of these medicinal plants, we performed enzymatic assays to assess the SOD and catalase activities in case of both treated and control Drosophila flies. Interestingly, the results support the free radical theory of aging as both these plant derivatives show high reactive oxygen species (ROS) scavenging activities. PMID:24967413
The complex nature of family support across the life span: Implications for psychological well-being.
Fuller-Iglesias, Heather R; Webster, Noah J; Antonucci, Toni C
This study examines the complex role of family networks in shaping adult psychological well-being over time. We examine the unique and interactive longitudinal influences of family structure (i.e., composition and size) and negative family relationship quality on psychological well-being among young (ages 18-34), middle-aged (ages 35-49), and older adults (ages 50+). A sample of 881 adults (72% White; 26% Black) was drawn from the longitudinal Social Relations, Age, and Health Study. Structural equation modeling indicated that among young and middle-aged adults, increasing family negativity was associated with increases in depressive symptoms over time. In contrast, among older adults, lowered proportion of family in network and an increasing number of family members in the network (i.e., family size) were associated with decreases in depressive symptoms. These findings were moderated by family negativity. Among older adults with low family negativity, having a lower proportion of family and larger family size were associated with decreasing depressive symptoms, but there was no effect among those reporting high family negativity. Overall, these results contribute to an increased understanding of the complex, developmental nature of how family support influences well-being across the life span and highlights unique age differences. PMID:25602936
Reconstitution of telomerase activity in normal human cells leads to elongation of telomeres and extended replicative life span
Homayoun Vaziri; Samuel Benchimol
Normal somatic cells have a finite life span [1] and lose telomeric DNA, present at the ends of chromosomes, each time they divide as a function of age in vivo or in culture [2¢4]. In contrast, many cancer cells and cell lines established from tumours maintain their telomere length by activation of an RNA¢protein complex called telomerase, an enzyme originally
Estimating age-dependent costs and benefits of roots with contrasting life span: comparing apples and oranges
Tjeerd J. Bouma; Ruth D. Yanai; Adrienne D. Elkin; Ulrich Hartmond; Dora E. Flores-Alva; David M. Eissenstat
The relation between root age and root function is poorly understood, despite its importance to root longevity. The effect of root age on respiration rates and P-32-uptake kinetics was determined for roots excavated from mature apple and citrus trees (median root life spans of 30 vs 300 d). To evaluate whether root longevity maximizes the efficiency of nutrient capture, daily
Modeling Life-Span Growth Curves of Cognition Using Longitudinal Data with Multiple Samples and Changing Scales of Measurement
ERIC Educational Resources Information Center
McArdle, John J.; Grimm, Kevin J.; Hamagami, Fumiaki; Bowles, Ryan P.; Meredith, William
The authors use multiple-sample longitudinal data from different test batteries to examine propositions about changes in constructs over the life span. The data come from 3 classic studies on intellectual abilities in which, in combination, 441 persons were repeatedly measured as many as 16 times over 70 years. They measured cognitive constructsģ
Although the maximum human life span of 122 years is well established, the genetic and biochemical changes
been shown to be activated by caloric restriction or oxidative stress, resulting in increased life span in attaining longevity [1]. So far, only a few genetic variants have been consistently reported to be associated with human longevity: the 4 allele of the apolipoprotein E (APOE) gene, a mortality factor [1
Living the Dream? A Qualitative Retrospective Study Exploring the Role of Adolescent Aspirations across the Life Span
ERIC Educational Resources Information Center
Ashby, Julie S.; Schoon, Ingrid
There is a lack of longitudinal research linking adolescent career aspirations to adult outcomes other than career and income attainment. Drawing on Nurmi's (2004) and Salmela-Aro, Aunola, and Nurmi's (2007) life-span model of motivation and using quantitative survey data at ages 16, 23, 33, 42, and 50 years, combined with retrospective interviewģ
A Life-Span, Relational, Public Health Model of Self-Regulation: Impact on Individual and Community Health
ERIC Educational Resources Information Center
Maniar, Swapnil; Zaff, Jonathan F.
In this chapter, the authors extend the ideas around the development of self-regulation and its impact on development by proposing a life-span, relational, public health model. They propose that the role of self-regulation should be understood across transitions from childhood to adulthood and through an individual and community perspective,ģ
Positive Regulation of DNA Double Strand Break Repair Activity during Differentiation of Long Life Span Cells: The Example of Adipogenesis
Aline Meulle; Bernard Salles; DaniĶle Daviaud; Philippe Valet; Catherine Muller; Mikhail V. Blagosklonny
Little information is available on the ability of terminally differentiated cells to efficiently repair DNA double strand breaks (DSBs), and one might reasonably speculate that efficient DNA repair of these threatening DNA lesions, is needed in cells of long life span with no or limited regeneration from precursor. Few tissues are available besides neurons that allow the study of DNA
Sex differences in aging, life span and spontaneous tumorigenesis in 129/Sv mice neonatally exposed to metformin.
Anisimov, Vladimir N; Popovich, Irina G; Zabezhinski, Mark A; Egormin, Peter A; Yurova, Maria N; Semenchenko, Anna V; Tyndyk, Margarita L; Panchenko, Andrey V; Trashkov, Alexandr P; Vasiliev, Andrey G; Khaitsev, Nikolai V
The perinatal (prenatal and early neonatal) period is a critical stage for hypothalamic programming of sexual differentiation as well as for the development of energy and metabolic homeostasis. We hypothesized that neonatal treatment with antidiabetic drug biguanide metformin would positively modify regulation of growth hormone--IGF-1--insulin signaling pathway slowing down aging and improving cancer preventive patterns in rodents. To test this hypothesis male and female 129/Sv mice were s.c. injected with metformin (100 mg/kg) at the 3rd, 5th and 7th days after birth. Metformin-treated males consumed less food and water and their body weight was decreased as compared with control mice practically over their entire lifespan. There were no significant differences in age-related dynamics of food and water consumption in females and they were heavier than controls. The fraction of mice with regular estrous cycles decreased with age and demonstrated a tendency to decrease in the females neonatally treated with metformin. Neonatal exposure to metformin practically failed to change the extent of hormonal and metabolic parameters in blood serum of male and female mice. In males, neonatal metformin treatment significantly increased the mean life span (+20%, P < 0.05) and slightly increased the maximum life span (+3.5%). In females, the mean life span and median in metformin-treated groups were slightly decreased (-9.1% and -13.8% respectively, P > 0.05) in comparison to controls, whereas mean life span of last 10% survivors and maximum life span were the same as in controls. Almost half (45%) of control male mice and 71.8% male mice neonatally exposed to metformin survived up to 800 d of age, the same age was achieved by 54.3% of mice in control female group and 30% of metformin-treated females (P < 0.03). Thus, neonatal metformin exposure slows down aging and prolongs lifespan in male but not in female mice. PMID:25483062
Cinnamomum cassia Bark in Two Herbal Formulas Increases Life Span in Caenorhabditis elegans via Insulin Signaling and Stress Response Pathways
Yu, Young-Beob; Dosanjh, Laura; Lao, Lixing; Tan, Ming; Shim, Bum Sang; Luo, Yuan
Background Proving the efficacy and corresponding mode of action of herbal supplements is a difficult challenge for evidence-based herbal therapy. A major hurdle is the complexity of herbal preparations, many of which combine multiple herbs, particularly when the combination is assumed to be vitally important to the effectiveness of the herbal therapy. This issue may be addressed through the use of contemporary methodology and validated animal models. Methods and Principal Findings In this study, two commonly used traditional herbal formulas, Shi Quan Da Bu Tang (SQDB) and Huo Luo Xiao Ling Dan (HLXL) were evaluated using a survival assay and oxidative stress biomarkers in a well-established C. elegans model of aging. HLXL is an eleven herb formula modified from a top-selling traditional herbal formula for the treatment of arthritic joint pain. SQDB consists of ten herbs often used for fatigue and energy, particularly in the aged. We demonstrate here that SQDB significantly extend life span in a C. elegans model of aging. Among all individual herbs tested, two herbs Cinnamomum cassia bark (Chinese pharmaceutical name: Cinnamomi Cortex, CIN) and Panax ginseng root (Chinese pharmaceutical name: Ginseng Radix, GS) significantly extended life span in C. elegans. CIN in both SQDB and HLXL formula extended life span via modulation of multiple longevity assurance genes, including genes involved in insulin signaling and stress response pathways. All the life-span-extending herbs (SQDB, CIN and GS) also attenuated levels of H2O2 and enhanced small heat shock protein expression. Furthermore, the life span-extending herbs significantly delayed human amyloid beta (A?)-induced toxicity in transgenic C. elegans expressing human A?. Conclusion/Significance These results validate an invertebrate model for rapid, systematic evaluation of commonly used Chinese herbal formulations and may provide insight for designing future evidence-based herbal therapy(s). PMID:20179756
Reproductive Life Events in the Population Living in the Vicinity of a Nuclear Waste Reprocessing Plant
Paris-Sud XI, Universitķ de
Reproductive Life Events in the Population Living in the Vicinity of a Nuclear Waste Reprocessing: There is concern about the health of populations living close to nuclear waste reprocessing plants. We conducted a comparative study on reproductive life events in the general population living near the nuclear waste
Correlated response in reproductive and life history traits to selection on testis length
Pitnick, Scott
Correlated response in reproductive and life history traits to selection on testis length, testis length, and other reproductive and life history traits, including body size, age at «rst underlying these interspeci«c patterns, we imposed replicated bidirectional selection for testis length
Routine vaccines across the life span, 2005. - PubMed - NCBI
Manual NCBI News PubMed PubMed Central (PMC) PubMed Clinical Queries PubMed Health All <span class="hlt">Literature Resources... Proteins BioSystems BLAST (Basic Local Alignment <span class="hlt">Search Tool)...
Life span and tissue distribution of 111indium-labeled blood platelets in hypomagnesemic lambs
Schneider, M.D.; Miller, J.K.; White, P.K.; Ramsey, N.
Circulating platelets may be activated by exposed triple-helical collagen in atherosclerotic lesions in Mg-deficient ruminants. Autologous platelets, labeled in vitro with 111In and determined to be active, were injected into 5 hypomagnesemic and 3 control lambs fed semipurified diets with 100 or 2,000 mg of Mg/kg of feed for 3 months. During the first 68 hours, 111In concentrations were 11 times higher in packed cells than in plasma. Packed-cell 111In increased 60% during the first 2 hours, probably due to initial tissue sequestration and later release of labeled platelets. Thereafter, platelet half-life span averaged 60 and 63 hours for hypomagnesemic and control lambs. After 68 hours, lambs were injected with native vascular collagen fibrils at 500 micrograms/kg of body weight to initiate reversible platelet aggregation. Within 1 minute, 83% of packed-cell 111In disappeared from circulation. Thirty minutes later, the lambs were euthanatized and necropsied and in the lungs, liver, and spleen, 111In averaged 24%, 19%, and 9%, respectively, of 111In injected 68 hours earlier. Organ deposits were not affected by Mg intake, but 111In in the lungs was somewhat lower in 2 lambs injected with inactivated collagen. Pathologic changes induced by reversible platelet aggregation were compatible with right ventricular failure complicated by pulmonary edema, similar to changes in hypomagnesemic lambs that died spontaneously. Platelets in blood exposed to vascular lesions in hypomagnesemic ruminants could be a major mortality risk factor in grass tetany disease.
Auditory Brainstem Response (ABR) Abnormalities across the Life Span of Rats Prenatally Exposed to Alcohol
Church, Michael W.; Hotra, John W.; Holmes, Pamela A.; Anumba, Jennifer I.; Jackson, Desmond A.; Adams, Brittany R.
Background Fetal Alcohol Syndrome is a leading cause of neurodevelopmental impairments (NDI) in developed countries. Sensory deficits can play a major role in NDI, yet few studies have investigated the effects of prenatal alcohol exposure on sensory function. In addition, there is a paucity of information on the life-long effects of prenatal alcohol exposure. Thus, we sought to investigate the effects of prenatal alcohol exposure on auditory function across the life span in an animal model. Based on prior findings with prenatal alcohol exposure and other forms of adverse prenatal environments, we hypothesized that animals prenatally exposed to alcohol would show an age-dependent pattern of (A) hearing and neurological abnormalities as post-weanling pups, (B) a substantial dissipation of such abnormalities in young adulthood, and (C) a resurgence of such abnormalities in middle-aged adulthood. Method Pregnant rats were randomly assigned to an untreated control (CON), a pair-fed control (PFC) or an alcohol treated group (ALC). The ALC dams were gavaged with 6 mg/kg alcohol daily from gestation day (GD) 6 to 21. The PFC dams were gavaged daily from GD6-21 with an isocaloric and isovolumetric water-based solution of Maltose-Dextrins and pair-fed to the ALC dams. The CON dams were the untreated group to which the ALC and CON groups were compared. Hearing and neurological functions in the offspring were assessed with the Auditory Brainstem Response (ABR) at the postnatal ages of 22, 220 and 520 days of age. Results & Conclusions In accord with our hypothesis, ABR abnormalities were first observed in the post-weanling pups, largely dissipated in young adulthood, and then resurged in middle-aged adulthood. This age-related pattern suggests that the ALC pups had a developmental delay that dissipated in young adulthood and an enhanced age-related deterioration that occurred in middle-aged adulthood. Such a pattern is consistent with the fetal programming hypothesis of adult-onset diseases (the Barker Hypothesis). Our findings have important clinical implications for the assessment and management of (A) childhood hearing disorders and their co-morbidities (i.e., speech-and-language, learning, and attention deficit disorders) and (B) enhanced age-related hearing and neurological degeneration in middle-aged adulthood that can result from prenatal alcohol exposure. We recommend hearing evaluation be a part of any long-term follow-up for FAS patients and patients exposed to any adverse prenatal environment. PMID:21815896
Influence of early-life nutrition on mortality and reproductive success during a subsequent famine
Lummaa, Virpi
-life conditions, no study on humans has demonstrated the predicted fitness benefit under low later-life nutrition of metabolic diseases. developmental plasticity | silver spoon | human life-history | DoHAD Nutrition duringInfluence of early-life nutrition on mortality and reproductive success during a subsequent famine
The Development of Memory Efficiency and Value-Directed Remembering across the Life Span: A Cross-Sectional Study of Memory and Selectivity
ERIC Educational Resources Information Center
Castel, Alan D.; Humphreys, Kathryn L.; Lee, Steve S.; Galvan, Adriana; Balota, David A.; McCabe, David P.
Although attentional control and memory change considerably across the life span, no research has examined how the ability to strategically remember important information (i.e., value-directed remembering) changes from childhood to old age. The present study examined this in different age groups across the life span (N = 320, 5-96 years old). Aģ
Tumorigenesis in high-dose total body irradiated rhesus monkeys--a life span study.
Hollander, Carel F; Zurcher, Chris; Broerse, Johan J
In the early sixties, studies have been performed at the TNO-Institutes for Health Research on acute effects of high dose total body irradiation (TBI) with X-rays and fission neutrons in Rhesus monkeys and the protective effect of autologous bone marrow transplantation (BMT). The surviving animals of this study were kept to investigate late radiation effects, ie, tumorigenesis. TBI in combination with chemotherapy, followed by rescue with BMT is increasingly used for the treatment of hematological malignancies and refractory autoimmune disease. The risk of radiation carcinogenesis after this treatment is of growing concern in man. Studies on tumor induction in nonhuman primates are of relevance in this context since the response of this species to radiation does not differ much from that in man. The group of long-term surviving monkeys comprised nine neutron irradiated animals (average total body dose 3A Gy, range 2.3-4.4 Gy) and 20 X-irradiated monkeys (average total body dose 7.1 Gy, range 2.8-8.6 Gy). A number of 21 age-matched nonirradiated Rhesus monkeys served as a control-group. All animals wereregularly screened for the occurrence of tumors. Complete necropsies were performed after natural death or euthanasia. At postirradiation intervals of 4-21 years an appreciable number of malignant tumors was observed. In the neutron irradiated group eight out of nine animals died with 1 or more malignant tumors. In the X-irradiated group this fraction was 10 out of 20. The tumors in the control group, in seven out of 21 animals, appeared at much older age compared with those in the irradiated cohorts. The histogenesis of the malignant tumors was diverse, as was the case for benign tumors. The observed shortening of latency periods and life span, as well as, the increase of mean number of tumors per tumor bearing animal for benign neoplasms parallels the trend observed for malignant tumors. The results of this study were compared to other radiation late effects after TBI followed by different BMT treatment modalities in Rhesus monkeys. The observation that the carcinogenic risk of TBI in the Rhesus monkeys is similar to that derived from the studies of the Japanese atomic bomb survivors and the increase of the risk by a factor of 8 emphasizes the need for regular screening for secondary radiation-induced tumors in long-term surviving patients after TBI followed by BMT. PMID:12696581
Global existence, large time behavior, and life span for a degenerate parabolic equation with inhomogeneous density and source
NASA Astrophysics Data System (ADS)
Zheng, Pan; Mu, Chunlai
This paper deals with the Cauchy problem for a degenerate parabolic equation with inhomogeneous density and source where , and . Firstly, we establish the secondary critical exponent on the decay asymptotic behavior of an initial value at infinity for the existence and non existence of global solutions of the Cauchy problem. Moreover, we give the large time behavior of the global solution. Finally, the precise estimate of life span for the solution is obtained.
Effect and mechanism of ginsenoside Rg3 on postoperative life span of patients with non-small cell lung cancer
Ping Lu; Wei Su; Zhan-hui Miao; Hong-rui Niu; Jing Liu; Qin-liang Hua
Objective: To explore the effect and mechanism of ginsenoside Rg3 (Shenyi Capsule, ????) on the postoperative life span of patients\\u000a with non-small cell lung cancer (NSCLC). Methods: The prospective, randomized, controlled method was adopted. One hundred and thirty-three patients with NSCLC were randomly\\u000a assigned to 3 groups: Shenyi Capsule group (43 cases), combined therapy group (Shenyi Capsule plus chemotherapy, 46
Influence of sources of dietary oils on the life span of stroke-prone spontaneously hypertensive rats
W. M. N. Ratnayake; L. Plouffe; R. Hollywood; M. R. L'Abbķ; N. Hidiroglou; G. Sarwar; R. Mueller
In recent studies, the life span of stroke-prone spontaneously hypertensive (SHRSP) rats was altered by a variety of dietary\\u000a fats. It was relatively shorter in rats fed canola oil as the sole source of fat. The present study was performed to find\\u000a out whether the fatty acid profile and the high content of sulfur compounds in canola oil could modulate
Self-esteem development across the life span: a longitudinal study with a large sample from Germany.
Orth, Ulrich; Maes, J³rgen; Schmitt, Manfred
The authors examined the development of self-esteem across the life span. Data came from a German longitudinal study with 3 assessments across 4 years of a sample of 2,509 individuals ages 14 to 89 years. The self-esteem measure used showed strong measurement invariance across assessments and birth cohorts. Latent growth curve analyses indicated that self-esteem follows a quadratic trajectory across the life span, increasing during adolescence, young adulthood, and middle adulthood, reaching a peak at age 60 years, and then declining in old age. No cohort effects on average levels of self-esteem or on the shape of the trajectory were found. Moreover, the trajectory did not differ across gender, level of education, or for individuals who had lived continuously in West versus East Germany (i.e., the 2 parts of Germany that had been separate states from 1949 to 1990). However, the results suggested that employment status, household income, and satisfaction in the domains of work, relationships, and health contribute to a more positive life span trajectory of self-esteem. The findings have significant implications, because they call attention to developmental stages in which individuals may be vulnerable because of low self-esteem (such as adolescence and old age) and to factors that predict successful versus problematic developmental trajectories. PMID:25485608
Positive Regulation of DNA Double Strand Break Repair Activity during Differentiation of Long Life Span Cells
Paris-Sud XI, Universitķ de
Span Cells: The Example of Adipogenesis Aline Meulle1,2 , Bernard Salles1,2 *, Danie`le Daviaud1 kinase (DNA-PK) activity. During the first 24 h following the commitment into adipogenesis, we show into adipogenesis due to an up-regulation of DNA-PK expression and activity. In opposition to the general view
Abstract Life-history theory predicts that different reproductive strategies should evolve in environments that differ in resource availability, mortality, seasonality, and in spatial or temporal variation. Within a population, the predicted optimal strategy is driven ...
Aspects of the life history and reproductive biology of the worm Paraprionospio pinnata
Mayfield, Stephen Manville
ASPECTS OF THE LIFE HISTORY AND REPRODUCTIVE BIOLOGY OF THE WORM PARAPRIONOSPIO PINNATA A Thesis by STEPHEN MANVILLE MAYFIELD Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree MASTER OF SCIENCE December 1988 Major Subject: Zoolcgy ASPECTS OF THE LIFE HISTORY AND REPRODUCTIVE BIOLOGY OF THE WORM PARAPRIONOSPIO PINNATA A Thesis by STEPHEN MANVILLE MAYFIELD Approved as to style and content by: Donald E . Harper...
Extension of Life Span by Impaired Glucose Metabolism in Caenorhabditis elegans Is Accompanied by Structural Rearrangements of the Transcriptomic Network
Priebe, Steffen; Menzel, Uwe; Zarse, Kim; Groth, Marco; Platzer, Matthias; Ristow, Michael; Guthke, Reinhard
Glucose restriction mimicked by feeding the roundworm Caenorhabditis elegans with 2-deoxy-D-glucose (DOG) - a glucose molecule that lacks the ability to undergo glycolysis - has been found to increase the life span of the nematodes considerably. To facilitate understanding of the molecular mechanisms behind this life extension, we analyzed transcriptomes of DOG-treated and untreated roundworms obtained by RNA-seq at different ages. We found that, depending on age, DOG changes the magnitude of the expression values of about 2 to 24 percent of the genes significantly, although our results reveal that the gross changes introduced by DOG are small compared to the age-induced changes. We found that 27 genes are constantly either up- or down-regulated by DOG over the whole life span, among them several members of the cytochrome P450 family. The monotonic change with age of the temporal expression patterns of the genes was investigated, leading to the result that 21 genes reverse their monotonic behaviour under impaired glycolysis. Put simply, the DOG-treatment reduces the gross transcriptional activity but increases the interconnectedness of gene expression. However, a detailed analysis of network parameters discloses that the introduced changes differ remarkably between individual signalling pathways. We found a reorganization of the hubs of the mTOR pathway when standard diet is replaced by DOG feeding. By constructing correlation based difference networks, we identified those signalling pathways that are most vigorously changed by impaired glycolysis. Taken together, we have found a number of genes and pathways that are potentially involved in the DOG-driven extension of life span of C. elegans. Furthermore, our results demonstrate how the network structure of ageing-relevant signalling pathways is reorganised under impaired glycolysis. PMID:24204961
Potentially Traumatic Events at Different Points in the Life Span and Mental Health: Findings From SHARE-Israel
Shrira, Amit; Shmotkin, Dov; Litwin, Howard
This study addressed the association between adversity cumulated at different points in the life span and present mental health. Data of 1,130 participants aged 50+ were drawn from the Israeli component of the Survey of Health, Ageing and Retirement in Europe (SHARE). Measures included an inventory of potentially traumatic events, mental distress (depressive symptoms), and well-being (quality of life, life satisfaction). Adversity reported to have occurred early in life was positively related to mental health (i.e., to lower distress and higher well-being), whereas adversity reported to occur in late life was negatively related (i.e., to higher distress and lower well-being). Additional analyses showed that the positive association between early-life adversity and mental health was mainly restricted to adversity in which the primary harm was to another person (other-oriented adversity). In contrast, the negative association between late-life adversity and mental health was mainly restricted to adversity in which the primary harm was to the self (self-oriented adversity). This study suggests that the differential association between cumulative adversity and mental health is best captured when accounting for both time of occurrence and adversity type. PMID:22506527
Reproductive rate and longevity in the waterstrider, Gerris buenoi LOCKEROWE' AND G. G. E. SCUDDER
Sokolowski, Marla
reproductive rates and long life spans. Negative relationships between reproductive rate and longev- ityNOTES Reproductive rate and longevity in the waterstrider, Gerris buenoi LOCKEROWE' AND G. G. E December 14, 1988 ROWE,L., and SCUDDER,G. G. E. 1990.Reproductive rate and longevity in the waterstrider
Effect and mechanism of ginsenoside Rg3 on postoperative life span of patients with non-small cell lung cancer
Ping Lu; Wei Su; Zhan-hui Miao; Hong-rui Niu; Jing Liu; Qin-liang Hua
ObjectiveĀĀTo explore the effect and mechanism of ginsenoside Rg3 (Shenyi Capsule, ????) on the postoperative life span of patients with\\u000a non-small cell lung cancer (NSCLC).\\u000a \\u000a \\u000a \\u000a MethodsĀĀThe prospective, randomized, controlled method was adopted. One hundred and thirtythree patients with NSCLC were randomly\\u000a assigned to 3 groups: Shenyi Capsule group (43 cases), combined therapy group (Shenyi Capsule plus chemotherapy, 46 cases),\\u000a and
New Concept of Prolonging the Service Life-Span for Asphalt Pavement of Expressways - Theory and Method of Swingy Lane Line on Flexible Pavement of Expressways
Zhi Wang; Dian-liang Xiao
How to prolong the service life-span for asphalt pavement of expressways has become a hot subject for many scientific workers. The author in this paper, after examining the commonly-seen manifestations of the asphalt pavement diseases and the track distribution laws from the vehicle tires on expressways, puts forward some new approaches and concepts for prolonging the service life-span for asphalt
A stockpile of ova in the grass frog Rana temporaria is established once for the life span. Do ovaries in amphibians and in mammals follow the same evolutionary strategy?
Ogielska, Maria; Kotusz, Agnieszka; Augusty?ska, Renata; Ihnatowicz, Jerzy; Pa?ko, ?ukasz
Most anuran amphibians produce high numbers of eggs during several consecutive breeding seasons. The question is still open whether oocytes are formed anew as a result of oogonial proliferation after each spawning or the definitive pool of oocytes is established during the juvenile period and is sufficient for the whole reproductive life span of a female. Our quantitative studies show that primary oogonia in adult female frogs can proliferate, but they fail to differentiate further and do not enter meiosis, and thereby there is no supplementation of new generations of oocytes after each spawning. Ovaries of one-year-old grass frogs contain (median) 53,447 diplotene oocytes, in two-years-old frogs this number decreased to 33,583 and eventually reached 25,679 in virgin mature females. More than 50% decrease in the total oocyte number was accompanied by massive degeneration (atresia) of oocytes. The final number of oocytes in a female forms a stock for 11-12 breeding seasons and exceeds the number of eggs produced during the potential reproductive life span of this species. The phylogenetic context of oocyte recruitment modes in the major clades of vertebrates is discussed in respect to their ability to replenish the stock (a renewable stock in ovaries named "open" vs. a non-renewable stock in ovaries named "closed"). PMID:23444316
Energy, quiescence and the cellular basis of animal life spans Jeffrey A. Stuart , Melanie F. Brown
Stuart, Jeffrey A.
is coincident with increased stress resistance and longevity. Here we review evidence that the rules of life in response to energetic flux. We provide a broad overview of the current knowledge of the relationships
Comparison of Building Energy Efficiency and Life Span for Different EnvelopesĀ
Li, Z.; Li, D.; Li, L.; Zhang, G.; Liu, J.
heat insulation measurement and heat preservation material position brings wall flaws and building life reduction. Comparisons of two building envelope heat insulation features are carried out by physical parameter measurements and calculation...
Fullness of Life as Minimal Unit: Science, Technology, Engineering, and Mathematics (STEM) Learning across the Life Span
ERIC Educational Resources Information Center
Roth, Wolff-Michael; Van Eijck, Michiel
Challenged by a National Science Foundation-funded conference, 2020 Vision: The Next Generation of STEM Learning Research, in which participants were asked to recognize science, technology, engineering, and mathematics (STEM) learning as lifelong, life-wide, and life-deep, we draw upon 20 years of research across the lifespan to propose a new wayģ
Difference in Muscle Quality Over the Adult Life-Span and Biological Correlates in the Baltimore Longitudinal Study of Aging
Moore, Ann Zenobia; Caturegli, Giorgio; Metter, E. Jeffrey; Makrogiannis, Sokratis; Resnick, Susan; Harris, Tamara B.; Ferrucci, Luigi
Background/Objectives Previous studies demonstrated that in older persons decline in muscle strength occurs with aging more rapidly than loss of muscle mass, highlighting the importance of muscle quality for functional outcomes in later life. We examine differences in a proxy measure of muscle quality across the adult life-span and explore potential mechanisms of muscle quality change through identification of cross-sectional correlates of muscle quality. Design Cross-sectional study. Setting/Participants 786 participants from the Baltimore Longitudinal Study of Aging (mean age 66.3 years, range: 26 ¢ 96 years). A sensitivity analysis was conducted in a subset of participants matched by sex, muscle mass and body size. Measurements Muscle quality, was operationalized as the ratio of knee-extension strength (isokinetic dynamometry) to thigh muscle cross-sectional area (computed tomography). Trends of muscle strength, area and muscle quality ratio across age were evaluated and the association of the muscle quality ratio with measures reflecting domains of cognitive function, motor control, peripheral nerve function, adiposity, glucose homeostasis, and inflammation were assessed through multivariate regression analyses. Results A linear relationship between age and muscle quality ratio was observed suggesting gradual decline in muscle quality across the adult life course. Associations were observed between muscle quality ratio and measures of adiposity as well as peroneal nerve motor conduction velocity, finger tapping speed, memory performance (p<.01). The association of muscle quality ratio with nerve conduction velocity was maintained after adjustment for anthropometrics (p<.05). Conclusion These observations suggest that muscle quality declines progressively with aging across the adult life span and is affected by both obesity and neurological factors. Studies are needed to clarify the mechanisms of these associations and their implications for functional outcomes. PMID:24438020
Telomerase-mediated life-span extension of human primary fibroblasts by human artificial chromosome (HAC) vector
Shitara, Shingo [Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503 (Japan); Kakeda, Minoru; Nagata, Keiko [Discovery Research Laboratories, Kirin Pharma Co., Ltd., 3 Miyahara-cho, Takasaki-shi, Gunma 370-1295 (Japan); Hiratsuka, Masaharu [Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503 (Japan); Sano, Akiko; Osawa, Kanako; Okazaki, Akiyo [Discovery Research Laboratories, Kirin Pharma Co., Ltd., 3 Miyahara-cho, Takasaki-shi, Gunma 370-1295 (Japan); Katoh, Motonobu; Kazuki, Yasuhiro; Oshimura, Mitsuo [Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503 (Japan); Tomizuka, Kazuma [Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503 (Japan); Discovery Research Laboratories, Kirin Pharma Co., Ltd., 3 Miyahara-cho, Takasaki-shi, Gunma 370-1295 (Japan)], E-mail: firstname.lastname@example.com
Telomerase-mediated life-span extension enables the expansion of normal cells without malignant transformation, and thus has been thought to be useful in cell therapies. Currently, integrating vectors including the retrovirus are used for human telomerase reverse transcriptase (hTERT)-mediated expansion of normal cells; however, the use of these vectors potentially causes unexpected insertional mutagenesis and/or activation of oncogenes. Here, we established normal human fibroblast (hPF) clones retaining non-integrating human artificial chromosome (HAC) vectors harboring the hTERT expression cassette. In hTERT-HAC/hPF clones, we observed the telomerase activity and the suppression of senescent-associated SA-{beta}-galactosidase activity. Furthermore, the hTERT-HAC/hPF clones continued growing beyond 120 days after cloning, whereas the hPF clones retaining the silent hTERT-HAC senesced within 70 days. Thus, hTERT-HAC-mediated episomal expression of hTERT allows the extension of the life-span of human primary cells, implying that gene delivery by non-integrating HAC vectors can be used to control cellular proliferative capacity of primary cultured cells.
Extended life span of human endometrial stromal cells transfected with cloned origin-defective, temperature-sensitive simian virus 40.
Rinehart, C A; Haskill, J S; Morris, J S; Butler, T D; Kaufman, D G
Human endometrial stromal cells transfected with an origin-defective, temperature-sensitive simian virus 40 recombinant plasmid are dependent on T-antigen function for proliferation and at the permissive temperature have an extended life span in culture. Southern blot analysis indicates that the transfected gene is present in low copy number, possibly at a single integration site. Normal stromal cells are capable of 10 to 20 population doublings in culture. Transfected cultures have been carried at the permissive temperature to 80 population doublings before crisis. In the multistep model of malignant transformation of human cells, these cells represent one of the earliest stages: extended but finite life span. We have used these cells to investigate alterations in signal transduction that may be responsible for this early stage of transformation caused by the large T antigen. Temperature shift experiments indicate that the expression of ornithine decarboxylase (ODC) but not of c-fos is altered by the large T antigen. Induction of c-fos by serum or 12-O-tetradecanoylphorbol-13-acetate is independent of temperature. However, in the transfected cells, the induction of ODC by asparagine or serum is greatly enhanced at the permissive temperature. This result indicates that the large T antigen acts downstream of c-fos but upstream of ODC expression in the signal-transducing cascade. Images PMID:1847463
Chronological and replicative life-span extension in Saccharomyces cerevisiae by increased dosage of alcohol dehydrogenase 1.
Reverter-Branchat, Gemma; Cabiscol, Elisa; Tamarit, Jordi; Sorolla, M Alba; Angeles de la Torre, M; Ros, Joaquim
Alcohol dehydrogenase 1 (Adh1)p catalyses the conversion of acetaldehyde to ethanol, regenerating NAD+. In Saccharomyces cerevisiae, Adh1p is oxidatively modified during ageing and, consequently, its activity becomes reduced. To analyse whether maintaining this activity is advantageous for the cell, a yeast strain with an extra copy of the ADH1 gene (2xADH1) was constructed, and the effects on chronological and replicative ageing were analysed. The strain showed increased survival in stationary phase (chronological ageing) due to induction of antioxidant enzymes such as catalase and superoxide dismutases. In addition, 2xADH1 cells displayed an increased activity of silent information regulator 2 (Sir2)p, an NAD+-dependent histone deacetylase, due to a higher NAD+/NADH ratio. As a consequence, a 30% extension in replicative life span was observed. Taken together, these results suggest that the maintenance of enzymes that participate in NAD+/NADH balancing is important to chronological and replicative life-span parameters. PMID:17975074
Evaluation of Resveratrol, Green Tea Extract, Curcumin, Oxaloacetic Acid, and Medium-Chain Triglyceride Oil on Life Span of Genetically Heterogeneous Mice
Miller, Richard A.; Astle, Clinton M.; Baur, Joseph A.; de Cabo, Rafael; Fernandez, Elizabeth; Guo, Wen; Javors, Martin; Kirkland, James L.; Nelson, James F.; Sinclair, David A.; Teter, Bruce; Williams, David; Zaveri, Nurulain; Nadon, Nancy L.; Harrison, David E.
The National Institute on Aging Interventions Testing Program (ITP) was established to evaluate agents that are hypothesized to increase life span and/or health span in genetically heterogeneous mice. Each compound is tested in parallel at three test sites. It is the goal of the ITP to publish all results, negative or positive. We report here on the results of lifelong treatment of mice, beginning at 4 months of age, with each of five agents, that is, green tea extract (GTE), curcumin, oxaloacetic acid, medium-chain triglyceride oil, and resveratrol, on the life span of genetically heterogeneous mice. Each agent was administered beginning at 4 months of age. None of these five agents had a statistically significant effect on life span of male or female mice, by log-rank test, at the concentrations tested, although a secondary analysis suggested that GTE might diminish the risk of midlife deaths in females only. PMID:22451473
Evaluation of resveratrol, green tea extract, curcumin, oxaloacetic acid, and medium-chain triglyceride oil on life span of genetically heterogeneous mice.
Strong, Randy; Miller, Richard A; Astle, Clinton M; Baur, Joseph A; de Cabo, Rafael; Fernandez, Elizabeth; Guo, Wen; Javors, Martin; Kirkland, James L; Nelson, James F; Sinclair, David A; Teter, Bruce; Williams, David; Zaveri, Nurulain; Nadon, Nancy L; Harrison, David E
The National Institute on Aging Interventions Testing Program (ITP) was established to evaluate agents that are hypothesized to increase life span and/or health span in genetically heterogeneous mice. Each compound is tested in parallel at three test sites. It is the goal of the ITP to publish all results, negative or positive. We report here on the results of lifelong treatment of mice, beginning at 4 months of age, with each of five agents, that is, green tea extract (GTE), curcumin, oxaloacetic acid, medium-chain triglyceride oil, and resveratrol, on the life span of genetically heterogeneous mice. Each agent was administered beginning at 4 months of age. None of these five agents had a statistically significant effect on life span of male or female mice, by log-rank test, at the concentrations tested, although a secondary analysis suggested that GTE might diminish the risk of midlife deaths in females only. PMID:22451473
Life Beyond the Eating Disorder: Education, Relationships, and Reproduction
Maxwell, Millie; Thornton, Laura M.; Root, Tammy L.; Pinheiro, Andrea Poyastro; Strober, Michael; Brandt, Harry; Crawford, Steve; Crow, Scott; Fichter, Manfred M.; Halmi, Katherine A.; Johnson, Craig; Kaplan, Allan S.; Keel, Pamela; Klump, Kelly L.; LaVia, Maria; Mitchell, James E.; Plotnicov, Kathy; Rotondo, Alessandro; Woodside, D. Blake; Berrettini, Wade H.; Kaye, Walter H.; Bulik, Cynthia M.
Objective We investigated sociodemographic characteristics in women with and without lifetime eating disorders. Method Participants were from a multi-site international study of eating disorders (N = 2096). Education level, relationship status, and reproductive status were examined across eating disorder subtypes and compared with a healthy control group. Results Overall, women with eating disorders were less educated than controls, and duration of illness and age of onset were associated with educational attainment. Menstrual status was associated with both relationship and reproductive status, but eating disorder subtypes did not differ significantly from each other or from healthy controls on these dimensions. Conclusion Differences in educational attainment, relationships, and reproduction do exist in individuals with eating disorders and are differentially associated with various eating disorder symptoms and characteristics. These data could assist with educating patients and family members about long-term consequences of eating disorders. PMID:20143323
Life-long spontaneous exercise does not prolong lifespan but improves health span in mice
Background Life expectancy at birth in the first world has increased from 35 years at the beginning of the 20th century to more than 80 years now. The increase in life expectancy has resulted in an increase in age-related diseases and larger numbers of frail and dependent people. The aim of our study was to determine whether life-long spontaneous aerobic exercise affects lifespan and healthspan in mice. Results Male C57Bl/6J mice, individually caged, were randomly assigned to one of two groups: sedentary (n = 72) or spontaneous wheel-runners (n = 72). We evaluated longevity and several health parameters including grip strength, motor coordination, exercise capacity (VO2max) and skeletal muscle mitochondrial biogenesis. We also measured the cortical levels of the brain-derived neurotrophic factor (BDNF), a neurotrophin associated with brain plasticity. In addition, we measured systemic oxidative stress (malondialdehyde and protein carbonyl plasma levels) and the expression and activity of two genes involved in antioxidant defense in the liver (that is, glutathione peroxidase (GPx) and manganese superoxide dismutase (Mn-SOD)). Genes that encode antioxidant enzymes are considered longevity genes because their over-expression may modulate lifespan. Aging was associated with an increase in oxidative stress biomarkers and in the activity of the antioxidant enzymes, GPx and Mn-SOD, in the liver in mice. Life-long spontaneous exercise did not prolong longevity but prevented several signs of frailty (that is, decrease in strength, endurance and motor coordination). This improvement was accompanied by a significant increase in the mitochondrial biogenesis in skeletal muscle and in the cortical BDNF levels. Conclusion Life-long spontaneous exercise does not prolong lifespan but improves healthspan in mice. Exercise is an intervention that delays age-associated frailty, enhances function and can be translated into the clinic. PMID:24472376
Recent Progress in Metabolic Signaling Pathways Regulating Aging and Life Span
The NIH Summit, Advances in Geroscience: Impact on Health Span and Chronic Disease, discusses several aspects of cellular degeneration that underlie susceptibility to chronic aging-associated diseases, morbidity, and mortality. In particular, the session on Metabolism focuses on the interrelationship between signal transduction, intermediary metabolism, and metabolic products and byproducts that contribute to pathophysiologic phenotypes and detrimental effects that occur during the aging process, thus leading to susceptibility to disease. Although it is well established that many metabolic pathways (ie, oxidative phosphorylation, insulin-stimulated glucose uptake) decline with age, it often remains uncertain if these are a cause or consequence of the aging process. Moreover, the mechanisms accounting for the decline in metabolic function remain enigmatic. Several novel and unexpected concepts are emerging that will help to define the roles of altered metabolic control in the degenerative mechanisms of aging. This brief review summarizes several of the topics to be discussed in the metabolism of aging session (http://www.geron.org/About%20Us/nih-geroscience-summit). PMID:24833582
The Experience and Regulation of Regret Across the Adult Life Span
Daniel Võstfjõll; Ellen Peters; Põr Bjõlkebring
\\u000a How do the experience, anticipation, and regulation of emotion influence decision making and how does it change with age?\\u000a Regret is a decision-related emotion that arises when a chosen outcome is, or is believed to be, worse than a nonchosen alternative.\\u000a The experience and anticipation of regret has been linked to important real-life decisions. However, previous research on\\u000a regret has,
Visualizing Life Zone Boundary Sensitivities Across Climate Models and Temporal Spans
Sisneros, Roberto R [ORNL] [ORNL; Huang, Jian [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); Ostrouchov, George [ORNL] [ORNL; Hoffman, Forrest M [ORNL] [ORNL
Life zones are a convenient and quantifiable method for delineating areas with similar plant and animal communities based on bioclimatic conditions. Such ecoregionalization techniques have proved useful for defining habitats and for studying how these habitats may shift due to environmental change. The ecological impacts of climate change are of particular interest. Here we show that visualizations of the geographic projection of life zones may be applied to the investigation of potential ecological impacts of climate change using the results of global climate model simulations. Using a multi-factor classification scheme, we show how life zones change over time based on quantitative model results into the next century. Using two straightforward metrics, we identify regions of high sensitivity to climate changes from two global climate simulations under two different greenhouse gas emissions scenarios. Finally, we identify how preferred human habitats may shift under these scenarios. We apply visualization methods developed for the purpose of displaying multivariate relationships within data, especially for situations that involve a large number of concurrent relationships. Our method is based on the concept of multivariate classification, and is implemented directly in VisIt, a production quality visualization package.
Cell specific radiation dosimetry in skeleton from life-span carcinogenesis studies. Final report
Webster, S.S.J.
The osteogenic sarcoma is the dominant life-threatening pathology in lifespan studies of beagles exposed to alpha-emitting bone-seeking radionuclides. It was deduced from these studies that certain skeletal sites are more prone to develop tumors. This project sought to determine the bone cells at risk and their cell-specific radiation dose. The cell-specific radiation dose values are related to loss and high Ra-226 and Pu-239 induced osteogenic sarcoma sites, to test different dose response hypothesis and predict the extent of effects in humans.
Cell specific radiation dosimetry in skeleton from life-span carcinogenesis studies
Webster, S.S.J.
The osteogenic sarcoma is the dominant life-threatening pathology in lifespan studies of beagles exposed to alpha-emitting bone-seeking radionuclides. It was deduced from these studies that certain skeletal sites are more prone to develop tumors. This project sought to determine the bone cells at risk and their cell-specific radiation dose. The cell-specific radiation dose values are related to loss and high Ra-226 and Pu-239 induced osteogenic sarcoma sites, to test different dose response hypothesis and predict the extent of effects in humans.
Metabolism, body size and life span: a case study in evolutionarily divergent populations of the garter snake (Thamnophis elegans).
Bronikowski, Anne; Vleck, David
We present a case study of metabolism, life history and aging in the western terrestrial garter snake (Thamnophis elegans). Early research in the field supported the rate-of-living hypothesis as an explanation of aging, which was based on an apparent negative relationship between mass-specific metabolic rate and lifespan in endotherms. This hypothesis in its original form has not withstood additional tests and comparisons between the two main lineages of endotherms-birds and mammals, but there is still much to be discovered of the causative links among rate of oxygen consumption, physiology and life history, particularly in ectothermic reptiles. We present data that show adult short-lived snakes, from naturally occurring ecotypes of garter snakes, have higher mass-specific resting metabolic rates at any given body mass (metabolic intensity) across a series of normal activity temperatures (15-32░C). The short-lived ecotype in this geographic region reaches a larger body size, and has life-history traits that place it at the fast end of a pace-of-life continuum (fast growth, early maturation, high reproductive output) relative to individuals of the small-bodied long-lived ecotype. The difference between ecotypes in metabolic intensity, even after acclimation to identical conditions, may reflect evolutionary divergence and genetic differences between ecotypes. The difference in metabolic intensity is not, however, present at birth, so an alternative is that developmental environment may permanently influence metabolic rate and life history. Such developmental canalization could lead to altered gene expression via environmental influences on the epigenome and result in altered metabolic trajectories in the snakes' natural habitats. PMID:21558247
Global existence, large time behavior, and life span for a degenerate parabolic equation with inhomogeneous density and source
NASA Astrophysics Data System (ADS)
Zheng, Pan; Mu, Chunlai
This paper deals with the Cauchy problem for a degenerate parabolic equation with inhomogeneous density and source |x|^{l1}u_t = div(u^{m - 1}|nabla u|^{? - 1}nabla u) + |x|^{l2}uq, quad(x, t) in {R}^N ū (0, infty), where {N ? 1, m + ? - 2 > 0, q > m + ? - 1}, and {0 ? l1 ? l2 < q - (m + ? - 1)/m + ? - 2N}. Firstly, we establish the secondary critical exponent on the decay asymptotic behavior of an initial value at infinity for the existence and non existence of global solutions of the Cauchy problem. Moreover, we give the large time behavior of the global solution. Finally, the precise estimate of life span for the solution is obtained.
Inflammation and Glucose Sensors: Use of Dexamethasone to Extend Glucose Sensor Function and Life Span in Vivo
Klueh, Ulrike; Kaur, Manjot; Montrose, David C.; Kreutzer, Donald L.
Background It has been generally accepted that the acute loss of sensor function is the consequence of sensor biofouling as a result of inflammation induced at sites of sensor implantation, as well as tissue trauma induced by the sensor and its implantation. Because anti-inflammatory therapies are used routinely to control inflammation in a wide variety of diseases, we hypothesized that anti-inflammatory therapy would likely extend glucose sensor function in vivo. To test this hypothesis, we utilized our recently developed mouse model of implantable glucose sensors and the potent anti-inflammatory steroid dexamethasone (DEX). Method For this study, glucose sensors were implanted subcutaneously into the head and neck area of mice and sensor function was determined up to 14 days postimplantation. These mice received a daily intraperitoneal injection of DEX at a dose of 1, 6, or 10 mg/kg body weight. Results Mice not treated with DEX lost sensor functionality very rapidly, usually within the first 24 hours postimplantation. Mice treated with DEX at the various doses had an increased sensor life span of up to 2 weeks postimplantation. Additionally, sensitivity was maintained in DEX-treated mice as compared to control mice (non-DEX treated). Histologic evaluation of tissue surrounding the site of sensor implantation had almost no inflammatory cells in DEX-treated mice, whereas control mice had an intense band of inflammation surrounding the site of sensor implantation. Conclusion To our knowledge this is the first study directly demonstrating that anti-inflammatory therapy can extend glucose sensor function in vivo and supports the key role of inflammation in loss of sensor function in vivo, as well as the uses of anti-inflammatory therapy as a potential key adjuvant in enhancing glucose sensor function and life span in vivo. PMID:19885112
Similar causes of various reproductive disorders in early life
Svechnikov, Konstantin; Stukenborg, Jan-Bernd; Savchuck, Iuliia; S÷der, Olle
During the past few decades, scientific evidence has been accumulated concerning the possible adverse effects of the exposure to environmental chemicals on the well-being of wildlife and human populations. One large and growing group of such compounds of anthropogenic or natural origin is referred to as endocrine-disrupting chemicals (EDCs), due to their deleterious action on the endocrine system. This concern was first focused on the control of reproductive function particularly in males, but has later been expanded to include all possible endocrine functions. The present review describes the underlying physiology behind the cascade of developmental events that occur during sexual differentiation of males and the specific role of androgen in the masculinization process and proper organogenesis of the external male genitalia. The impact of the genetic background, environmental exposures and lifestyle factors in the etiology of hypospadias, cryptorchidism and testicular cancer are reviewed and the possible role of EDCs in the development of these reproductive disorders is discussed critically. Finally, the possible direct and programming effects of exposures in utero to widely use therapeutic compounds, environmental estrogens and other chemicals on the incidence of reproductive abnormalities and poor semen quality in humans are also highlighted. PMID:24369133
The evolution of life histories in garter snakes: Reproduction, aging, and the physiology of trade-offs
Amanda M. Sparkman
Life-history theory predicts that optimal life histories are shaped by trade-offs among traits expressed in different evolutionary and ecological contexts. Fast growth and high reproduction are predicted to trade off with lifespan, with the result that \\
Sickle cell disease: an opportunity for palliative care across the life span.
Wilkie, Diana J; Johnson, Bonnye; Mack, A Kyle; Labotka, Richard; Molokie, Robert E
Sickle cell disease is a chronic illness that affects patients physically and emotionally and can do so at an early age. An ecological model of palliative care that involves improved communication among the health care team, patients, and their families can be beneficial. Open and honest communication regarding advance care planning, disease management, relief of pain and other symptoms, and bereavement and grief are all important for the patient, family, and health care team. Given the multiple acute and chronic complications of sickle cell disease, an approach to care that is holistic and comprehensive may help to improve a patient's biologic function and the perceived health, functional status, and quality of life of the patient and family. PMID:20804884
Reproductive Stage of the Life Cycle in the Rhizocephalan Barnacle Polyascus polygenea (Crustacea: Cirripedia)
O. M. Korn; A. I. Shukalyuk; A. V. Trofimova; V. V. Isaeva
The specific features of the reproductive stage of the life cycle have been studied in the rhizocephalan barnacle Polyascus polygenea, a parasite of the coastal crab Hemigrapsus sanguineus. It is shown that a single crab can bear 1 to 8 externae of P. polygenea. The fecundity of the parasite depends on the size of the externae and their number on
How Much Should We Weigh for a Long and Healthy Life Span? The Need to Reconcile Caloric Restriction versus Longevity with Body Mass Index versus Mortality Data.
Lorenzini, Antonello
Total caloric restriction (CR) without malnutrition is a well-established experimental approach to extend life span in laboratory animals. Although CR in humans is capable of shifting several endocrinological parameters, it is not clear where the minimum inflection point of the U-shaped curve linking body mass index (BMI) with all-cause mortality lies. The exact trend of this curve, when used for planning preventive strategies for public health is of extreme importance. Normal BMI ranges from 18.5 to 24.9; many epidemiological studies show an inverse relationship between mortality and BMI inside the normal BMI range. Other studies show that the lowest mortality in the entire range of BMI is obtained in the overweight range (25-29.9). Reconciling the extension of life span in laboratory animals by experimental CR with the BMI-mortality curve of human epidemiology is not trivial. In fact, one interpretation is that the CR data are identifying a known: "excess fat is deleterious for health"; although a second interpretation may be that: "additional leanness from a normal body weight may add health and life span delaying the process of aging." This short review hope to start a discussion aimed at finding the widest consensus on which weight range should be considered the "healthiest" for our species, contributing in this way to the picture of what is the correct life style for a long and healthy life span. PMID:25126085
Serum lipid concentrations and mean life span are modulated by dietary polyunsaturated fatty acids in the senescence-accelerated mouse.
Umezawa, M; Takeda, T; Kogishi, K; Higuchi, K; Matushita, T; Wang, J; Chiba, T; Hosokawa, M
The senescence-accelerated mouse (SAMP8) is an animal model used in studies of aging. This study was undertaken to investigate the effects of dietary PUFA on longevity (Experiment 1) and serum lipid concentrations (Experiment 2) in SAMP8 mice. Male mice were fed either an (n-3) PUFA-rich (9 g/100 g perilla oil) or an (n-6) PUFA-rich (9 g/100 g safflower oil) diet beginning at 6 wk of age. Experiment 1: The groups did not differ in body weight gain, but those fed perilla oil had significantly lower scores of senescence relative to those fed safflower oil (P<0.05). The mean life span of mice fed perilla oil was 357+/-21 d and of those fed safflower oil, 426+/-24 d (P<0.05). Pathological studies revealed that the incidence of tumors was significantly lower in the perilla oil group than in the safflower oil group (P<0.05). Approximately half the mice fed perilla oil had died after 10 mo, and the direct causes closely connected with death could not be specified. Experiment 2: The serum total cholesterol, HDL cholesterol, triglyceride and phospholipid concentrations were significantly lower in the perilla oil group than in the safflower oil group (P<0.01). A marked decrease of serum HDL cholesterol and apolipoprotein A-II (ApoA-II)concentrations in advanced age were observed in the mice fed perilla oil (P<0.01). Ten-month-old mice fed perilla oil had a significantly greater ratio of apolipoprotein A-I (ApoA-I) to ApoA-II than those fed safflower oil. Separation of HDL subfractions revealed that the smaller HDL species were much more abundant than the larger HDL species in both dietary oil groups. These findings suggest that dietary (n-3) and (n-6) PUFA differ in their effects on serum lipid metabolism which may modulate the mean life span of SAMP8 mice fed each dietary oil. PMID:10720173
Differential reproductive responses to stress reveal the role of life-history strategies within a species.
Schultner, J; Kitaysky, A S; Gabrielsen, G W; Hatch, S A; Bech, C
Life-history strategies describe that 'slow'- in contrast to 'fast'-living species allocate resources cautiously towards reproduction to enhance survival. Recent evidence suggests that variation in strategies exists not only among species but also among populations of the same species. Here, we examined the effect of experimentally induced stress on resource allocation of breeding seabirds in two populations with contrasting life-history strategies: slow-living Pacific and fast-living Atlantic black-legged kittiwakes. We tested the hypothesis that reproductive responses in kittiwakes under stress reflect their life-history strategies. We predicted that in response to stress, Pacific kittiwakes reduce investment in reproduction compared with Atlantic kittiwakes. We exposed chick-rearing kittiwakes to a short-term (3-day) period of increased exogenous corticosterone (CORT), a hormone that is released during food shortages. We examined changes in baseline CORT levels, parental care and effects on offspring. We found that kittiwakes from the two populations invested differently in offspring when facing stress. In response to elevated CORT, Pacific kittiwakes reduced nest attendance and deserted offspring more readily than Atlantic kittiwakes. We observed lower chick growth, a higher stress response in offspring and lower reproductive success in response to CORT implantation in Pacific kittiwakes, whereas the opposite occurred in the Atlantic. Our findings support the hypothesis that life-history strategies predict short-term responses of individuals to stress within a species. We conclude that behaviour and physiology under stress are consistent with trade-off priorities as predicted by life-history theory. We encourage future studies to consider the pivotal role of life-history strategies when interpreting inter-population differences of animal responses to stressful environmental events. PMID:24089339
Differential reproductive responses to stress reveal the role of life-history strategies within a species
Schultner, J.; Kitaysky, A. S.; Gabrielsen, G. W.; Hatch, S. A.; Bech, C.
Life-history strategies describe that æslowÆ- in contrast to æfastÆ-living species allocate resources cautiously towards reproduction to enhance survival. Recent evidence suggests that variation in strategies exists not only among species but also among populations of the same species. Here, we examined the effect of experimentally induced stress on resource allocation of breeding seabirds in two populations with contrasting life-history strategies: slow-living Pacific and fast-living Atlantic black-legged kittiwakes. We tested the hypothesis that reproductive responses in kittiwakes under stress reflect their life-history strategies. We predicted that in response to stress, Pacific kittiwakes reduce investment in reproduction compared with Atlantic kittiwakes. We exposed chick-rearing kittiwakes to a short-term (3-day) period of increased exogenous corticosterone (CORT), a hormone that is released during food shortages. We examined changes in baseline CORT levels, parental care and effects on offspring. We found that kittiwakes from the two populations invested differently in offspring when facing stress. In response to elevated CORT, Pacific kittiwakes reduced nest attendance and deserted offspring more readily than Atlantic kittiwakes. We observed lower chick growth, a higher stress response in offspring and lower reproductive success in response to CORT implantation in Pacific kittiwakes, whereas the opposite occurred in the Atlantic. Our findings support the hypothesis that life-history strategies predict short-term responses of individuals to stress within a species. We conclude that behaviour and physiology under stress are consistent with trade-off priorities as predicted by life-history theory. We encourage future studies to consider the pivotal role of life-history strategies when interpreting inter-population differences of animal responses to stressful environmental events. PMID:24089339
A new life-span approach to conscientiousness and health: combining the pieces of the causal puzzle.
Friedman, Howard S; Kern, Margaret L; Hampson, Sarah E; Duckworth, Angela Lee
Conscientiousness has been shown to predict healthy behaviors, healthy social relationships, and physical health and longevity. The causal links, however, are complex and not well elaborated. Many extant studies have used comparable measures for conscientiousness, and a systematic endeavor to build cross-study analyses for conscientiousness and health now seems feasible. Of particular interest are efforts to construct new, more comprehensive causal models by linking findings and combining data from existing studies of different cohorts. Although methodological perils can threaten such integration, such efforts offer an early opportunity to enliven a life course perspective on conscientiousness, to see whether component facets of conscientiousness remain related to each other and to relevant mediators across broad spans of time, and to bolster the findings of the few long-term longitudinal studies of the dynamics of personality and health. A promising approach to testing new models involves pooling data from extant studies as an efficient and heuristic prelude to large-scale testing of interventions. PMID:23088747
Comparative longitudinal structural analyses of the growth and decline of multiple intellectual abilities over the life span.
McArdle, John J; Ferrer-Caja, Emilio; Hamagami, Fumiaki; Woodcock, Richard W
Latent growth curve techniques and longitudinal data are used to examine predictions from the theory of fluid and crystallized intelligence (Gf-Gc theory; J. L. Horn & R. B. Cattell, 1966, 1967). The data examined are from a sample (N approximately 1,200) measured on the Woodcock-Johnson Psycho-Educational Battery-Revised (WJ-R). The longitudinal structural equation models used are based on latent growth models of age using two-occasion "accelerated" data (e.g., J. J. McArdle & R. Q. Bell, 2000; J. J. McArdle & R. W. Woodcock, 1997). Nonlinear mixed-effects growth models based on a dual exponential rate yield a reasonable fit to all life span cognitive data. These results suggest that most broad cognitive functions fit a generalized curve that rises and falls. Novel multilevel models directly comparing growth curves show that broad fluid reasoning (Gf) and acculturated crystallized knowledge (Gc) have different growth patterns. In all comparisons, any model of cognitive age changes with only a single g factor yields an overly simplistic view of growth and change over age. PMID:11806695
The SNF1 Kinase Ubiquitin-associated Domain Restrains Its Activation, Activity, and the Yeast Life Span.
Jiao, Rubin; Postnikoff, Spike; Harkness, Troy A; Arnason, Terra G
The enzyme family of heterotrimeric AMP-dependent protein kinases is activated upon low energy states, conferring a switch toward energy-conserving metabolic pathways through immediate kinase actions on enzyme targets and delayed alterations in gene expression through its nuclear relocalization. This family is evolutionarily conserved, including the presence of a ubiquitin-associated (UBA) motif in most catalytic subunits. The potential for the UBA domain to promote protein associations or direct subcellular location, as seen in other UBA-containing proteins, led us to query whether the UBA domain within the yeast AMP-dependent protein kinase ortholog, SNF1 kinase, was important in these aspects of its regulation. Here, we demonstrate that conserved UBA motif mutations significantly alter SNF1 kinase activation and biological activity, including enhanced allosteric subunit associations and increased oxidative stress resistance and life span. Significantly, the enhanced UBA-dependent longevity and oxidative stress response are at least partially dependent on the Fkh1 and Fkh2 stress response transcription factors, which in turn are shown to influence Snf1 gene expression. PMID:25869125
Evidence for a Relationship between Longevity of Mammalian Species and Life Spans of Normal Fibroblasts in vitro and Erythrocytes in vivo
Dan Rohme
The replicative life spans of mammalian fibroblasts in vitro were studied in a number of cell cultures representing eight species. Emphasis was placed on determining the population doubling level at which phase III (a period of decrease in the rate of proliferation) and chromosomal alterations occur. All the cell cultures studied went through a growth crisis, a period of apparent
Chronological Life Span Method Serial Dilutions and Pin Stamps Materials: Sterile 96-well plates, YPD liquid medium, YPD-G418 agar plates (~20 ml, cured on bench
Aris, John P.
Chronological Life Span Method Ł Serial Dilutions and Pin Stamps Materials: Sterile 96-well plates reservoir, multichannel pipetter. 1. Use a 96-well plate for dilutions and pin stamping. Use 6 wells.2 X 10-4 4. Use pin stamp to `stamp' diluted samples onto YPD-G418 plates. Dip pin stamp in 100
Vegetable Oils High in Phytosterols Make Erythrocytes Less Deformable and Shorten the Life Span of Stroke-Prone Spontaneously Hypertensive Rats1,2
Walisundera M. N. Ratnayake; Mary R. L'Abbe ┤; Rudi Mueller; Stephen Hayward; Louise Plouffe; Rudy Hollywood; Keith Trick
Previous studies have shown that canola oil (CA), compared with soybean oil (SO), shortens the life span of stroke-prone spontaneously hypertensive (SHRSP) rats, a widely used model for hemorrhagic stroke. SHRSP rats are highly sensitive to dietary cholesterol manipulations because a deficiency of membrane cholesterol makes their cell membranes weak and fragile. Phytosterols, abundant in CA but not in SO,
Human longevity and early reproduction in pre-industrial Sami populations
Helle, Samuli
Human longevity and early reproduction in pre-industrial Sami populations S. HELLE,* P. KA© A© R for the long post-reproductive life span in humans. Introduction Senescence, i.e. decrease in survival Keywords: evolution; fecundity; humans; life cycle; longevity; natural selection; senescence. Abstract
The reproductive cycle and life history of the Arctic copepod Calanus glacialis in the White Sea
K. N. Kosobokova
Seasonal variations in the gonad development and sex ratio of copepodite stage V (CV) and adults were examined from February\\u000a to November in order to understand the reproductive cycle and the life history of Calanus glacialis in the White Sea. Gonad maturation, sexual differentiation and moulting to adults take place during the 2nd year of development.\\u000a Energy accumulation takes place
Reproductive life history correlates of early and late sexual maturation in female Mongolian gerbils (Meriones unguiculatus)
Age at vaginal introitus is bimodally distributed in female domesticated Mongolian gerbils; some exhibit vaginal perforation before eye-opening (day 16), others after weaning (day 25). We found early- and late-maturing female gerbils to ditfer significantly in reproductive life history. Early-maturing females first reproduced when younger. had more litters, with more young per litter, and consequently had more than twice as
Reproductive ecology and early life history of a lacustrine sculpin, Cottus extensus (Teleostei, Cottidae)
James R. Ruzycki; Wayne A. Wurtsbaugh; Clyde Lay
Using a variety of sampling techniques and observations we describe aspects of the reproductive ecology and early life-history of Bear Lake sculpin, Cottus extensus, a species endemic to Bear Lake, Utah-Idaho. Adult sculpin spawned in shallow water (0.5¢6.0 m depths) in cavities beneath large cobbles and boulders. During 1993, egg mass densities were highest (> 4.0 m2) at 1.0¢2.0 m
Body Size, Growth and Life Span: Implications for the Polewards Range Shift of Octopus tetricus in South-Eastern Australia
Ramos, Jorge E.; Pecl, Gretta T.; Moltschaniwskyj, Natalie A.; Strugnell, Jan M.; Le¾n, Rafael I.; Semmens, Jayson M.
Understanding the response of any species to climate change can be challenging. However, in short-lived species the faster turnover of generations may facilitate the examination of responses associated with longer-term environmental change. Octopus tetricus, a commercially important species, has undergone a recent polewards range shift in the coastal waters of south-eastern Australia, thought to be associated with the southerly extension of the warm East Australian Current. At the cooler temperatures of a polewards distribution limit, growth of a species could be slower, potentially leading to a bigger body size and resulting in a slower population turnover, affecting population viability at the extreme of the distribution. Growth rates, body size, and life span of O. tetricus were examined at the leading edge of a polewards range shift in Tasmanian waters (40░S and 147░E) throughout 2011. Octopus tetricus had a relatively small body size and short lifespan of approximately 11 months that, despite cooler temperatures, would allow a high rate of population turnover and may facilitate the population increase necessary for successful establishment in the new extended area of the range. Temperature, food availability and gender appear to influence growth rate. Individuals that hatched during cooler and more productive conditions, but grew during warming conditions, exhibited faster growth rates and reached smaller body sizes than individuals that hatched into warmer waters but grew during cooling conditions. This study suggests that fast growth, small body size and associated rapid population turnover may facilitate the range shift of O. tetricus into Tasmanian waters. PMID:25090250
Deletion of Brca2 exon 27 causes hypersensitivity to DNA crosslinks, chromosomal instability, and reduced life span in mice
NASA Technical Reports Server (NTRS)
Donoho, Greg; Brenneman, Mark A.; Cui, Tracy X.; Donoviel, Dorit; Vogel, Hannes; Goodwin, Edwin H.; Chen, David J.; Hasty, Paul
The Brca2 tumor-suppressor gene contributes to genomic stability, at least in part by a role in homologous recombinational repair. BRCA2 protein is presumed to function in homologous recombination through interactions with RAD51. Both exons 11 and 27 of Brca2 code for domains that interact with RAD51; exon 11 encodes eight BRC motifs, whereas exon 27 encodes a single, distinct interaction domain. Deletion of all RAD51-interacting domains causes embryonic lethality in mice. A less severe phenotype is seen with BRAC2 truncations that preserve some, but not all, of the BRC motifs. These mice can survive beyond weaning, but are runted and infertile, and die very young from cancer. Cells from such mice show hypersensitivity to some genotoxic agents and chromosomal instability. Here, we have analyzed mice and cells with a deletion of only the RAD51-interacting region encoded by exon 27. Mice homozygous for this mutation (called brca2(lex1)) have a shorter life span than that of control littermates, possibly because of early onsets of cancer and sepsis. No other phenotype was observed in these animals; therefore, the brca2(lex1) mutation is less severe than truncations that delete some BRC motifs. However, at the cellular level, the brca2(lex1) mutation causes reduced viability, hypersensitivity to the DNA interstrand crosslinking agent mitomycin C, and gross chromosomal instability, much like more severe truncations. Thus, the extreme carboxy-terminal region encoded by exon 27 is important for BRCA2 function, probably because it is required for a fully functional interaction between BRCA2 and RAD51. Copyright 2003 Wiley-Liss, Inc.
Maternal thermal environment induces plastic responses in the reproductive life history of oviparous lizards.
Ma, Liang; Sun, Bao-Jun; Li, Shu-Ran; Sha, Wei; Du, Wei-Guo
Adaptive plasticity may shift phenotypic traits close to a new optimum for directional selection and probably facilitates adaptive evolution in new environments. However, such plasticity has rarely been reported in life-history evolution, despite overwhelming evidence of life-history variation both among and within species. In this study, the temperatures experienced by gravid females of Scincella modesta were manipulated to identify maternally induced plasticity in reproductive traits and the significance of such changes in the evolution of life history. Consistent with the geographic pattern of life history, the study demonstrated that low temperatures delayed egg oviposition, resulting in a more advanced embryonic developmental stage at oviposition and shorter incubation periods compared with warm temperatures. In addition, females maintained at low temperatures produced larger eggs and hence heavier hatchlings than those at warm temperatures. This study demonstrated that environmental temperatures can induce plastic responses in egg retention and offspring size, and these maternally mediated changes in reproductive life history seem to be adaptive in the light of latitudinal clines of these traits in natural populations. PMID:25244379
The roles of the immune system in women's reproduction: evolutionary constraints and life history trade-offs.
Abrams, Elizabeth T; Miller, Elizabeth M
Life history theory posits that, as long as survival is assured, finite resources are available for reproduction, maintenance, and growth/storage. To maximize lifetime reproductive success, resources are subject to trade-offs both within individuals and between current and future investment. For women, reproducing is costly and time-consuming; the bulk of available resources must be allocated to reproduction at the expense of more flexible systems like immune function. When reproducing women contract infectious diseases, the resources required for immune activation can fundamentally shift the patterns of resource allocation. Adding to the complexity of the reproductive-immune trade-offs in women are the pleiotropic effects of many immune factors, which were modified to serve key roles in mammalian reproduction. In this review, we explore the complex intersections between immune function and female reproduction to situate proximate immunological processes within a life history framework. After a brief overview of the immune system, we discuss some important physiological roles of immune factors in women's reproduction and the conflicts that may arise when these factors must play dual roles. We then discuss the influence of reproductive-immune trade-offs on the patterning of lifetime reproductive success: (1) the effect of immune activation/infectious disease on the timing of life history events; (2) the role of the immune system, immune activation, and infectious disease on resource allocation within individual reproductive events, particularly pregnancy; and (3) the role of the immune system in shaping the offspring's patterns of future life history trade-offs. We close with a discussion of future directions in reproductive immunology for anthropologists. PMID:22101690
Giant protist Nummulites and its Eocene environment: Life span and habitat insights from ?18O and ?13C data from Nummulites and Venericardia, Hampshire basin, UK
NASA Astrophysics Data System (ADS)
Purton, Louise M. A.; Brasier, Martin D.
Nummulites are virtually extinct, giant marine protists that reached up to 160 mm diameter during the warmest climatic phase of the Cenozoic. Until now, their life span and paleoenvironmental tolerance have remained enigmatic. Pioneering the use of high-resolution drilling techniques in Nummulites, we show that both N. laevigatus and coeval bivalve Venericardia planicosta from the Lutetian of Hampshire, United Kingdom (ca. 50 42.5 Ma), underwent strong, annual alternations in carbon and oxygen isotopes, possibly reflecting tolerance of broad environmental variation. Our data demonstrate a life span of at least 5 yr for N. laevigatus, and we estimate that the largest species may have lived for more than 100 yr.
[Late sequelae of exposure to ionizing radiation with various LET's. Effect of dose rate and fractionation on changes in the life span of rats].
Vershinina, S F
In experiments with 2120 albino mongrel rats their life span was followed up after the effect of various types of radiation (for instance, gamma-neutron radiation of 0.9 MeV and gamma- and X-rays) at different exposure schedules (that is, whole-body irradiation with doses from LD0/30 to LD100/30 and fractionated at 24 and 72 hour intervals and dose--rates varying from 0.00042 Gy/min to 1.02 Gy/min). The type of radiation, the dose--rate, single and cumulative doses, the number of fractions and the interval between them were estimated with respect to their contribution to life span shortening. PMID:3041437
Differential longitudinal changes in cortical thickness, surface area and volume across the adult life span: regions of accelerating and decelerating change.
Storsve, Andreas B; Fjell, Anders M; Tamnes, Christian K; Westlye, Lars T; Overbye, Knut; Aasland, Hilde W; Walhovd, Kristine B
Human cortical thickness and surface area are genetically independent, emerge through different neurobiological events during development, and are sensitive to different clinical conditions. However, the relationship between changes in the two over time is unknown. Additionally, longitudinal studies have almost invariably been restricted to older adults, precluding the delineation of adult life span trajectories of change in cortical structure. In this longitudinal study, we investigated changes in cortical thickness, surface area, and volume after an average interval of 3.6 years in 207 well screened healthy adults aged 23-87 years. We hypothesized that the relationships among metrics are dynamic across the life span, that the primary contributor to cortical volume reductions in aging is cortical thinning, and that magnitude of change varies with age and region. Changes over time were seen in cortical area (mean annual percentage change [APC], -0.19), thickness (APC, -0.35), and volume (APC, -0.51) in most regions. Volume changes were primarily explained by changes in thickness rather than area. A negative relationship between change in thickness and surface area was found across several regions, where more thinning was associated with less decrease in area, and vice versa. Accelerating changes with increasing age was seen in temporal and occipital cortices. In contrast, decelerating changes were seen in prefrontal and anterior cingulate cortices. In conclusion, a dynamic relationship between cortical thickness and surface area changes exists throughout the adult life span. The mixture of accelerating and decelerating changes further demonstrates the importance of studying these metrics across the entire adult life span. PMID:24948804
Feeding into old age: long-term effects of dietary fatty acid supplementation on tissue composition and life span in mice
Teresa G. Valencak; Thomas Ruf
Smaller mammals, such as mice, possess tissues containing more polyunsaturated fatty acids (PUFAs) than larger mammals, while\\u000a at the same time live shorter lives. These relationships have been combined in the æmembrane pacemaker hypothesis of agingÆ.\\u000a It suggests that membrane PUFA content might determine an animalÆs life span. PUFAs in general and certain long-chain PUFAs\\u000a in particular, are highly prone
The Importance of Geological Models in Understanding and Predicting the Life Span of Rockslide Dams: The Case of Scanno Lake, Central Italy
G. Bianchi-Fasani; C. Esposito; M. Petitta; G. Scarascia-Mugnozza; M. Barbieri; E. Cardarelli; M. Cercato; G. Di Filippo
\\u000a In order to explain the long life span of the Scanno rockslide-avalanche dammed lake (Central Italy), whose age of impoundment\\u000a is older than 2,300 years, and to get indications about its present and future stability conditions, it was assumed of fundamental\\u000a importance to build a representative geological model aimed at defining (i) the geometry of the boundary surface between the
Genome-Wide Screen in Saccharomyces cerevisiae Identifies Vacuolar Protein Sorting, Autophagy, Biosynthetic, and tRNA Methylation Genes Involved in Life Span Regulation
Paola Fabrizio; Shawn Hoon; Mehrnaz Shamalnasab; Abdulaye Galbani; Min Wei; Guri Giaever; Corey Nislow; Valter D. Longo
The study of the chronological life span of Saccharomyces cerevisiae, which measures the survival of populations of non-dividing yeast, has resulted in the identification of homologous genes and pathways that promote aging in organisms ranging from yeast to mammals. Using a competitive genome-wide approach, we performed a screen of a complete set of approximately 4,800 viable deletion mutants to identify
Rapid weight gain after birth predicts life history and reproductive strategy in Filipino males
Kuzawa, Christopher W.; McDade, Thomas W.; Adair, Linda S.; Lee, Nanette
Ecological cues during prenatal and postnatal development may allow organisms to adjust reproductive strategy. The hypothalamic-pituitary-gonadal (HPG) axis is a prime candidate for adaptive plasticity as a result of its critical period of birth to 6 mo (B6M) in humans and the role of testosterone in the development and maintenance of costly sexually dimorphic somatic and behavioral traits. We hypothesized that weight velocity specific to B6M would predict male life history characteristics, including maturational timing, reproductive hormones, adult size, strength, and sexual activity. Data come from 770 Filipino men (age 20.5¢22.5 y) followed since birth, with predictor variables including birth weight and weight velocities calculated at 6-mo intervals during the first 2 y of life. As expected, infants who were breastfed experienced less diarrhea, lived in wealthier households with better hygiene, and grew faster from B6M. Males with rapid B6M growth reached puberty earlier and, as young adults, had higher testosterone levels, were taller, more muscular, and had higher grip strength. They also had sex earlier and were more likely to report having had sex in the past month, resulting in more lifetime sex partners. Relationships between B6M weight gain and physical outcomes were generally not present or weaker in female subjects. We conclude that rapid weight gain specific to the brief postnatal hypothalamic-pituitary-gonadal critical period predicts early maturation and sexual activity, elevated hormone production, and more costly adult somatic characteristics among the male subjects in this sample. These findings provide evidence for early life developmental plasticity in male life history and reproductive strategy in humans. PMID:20837542
Excess Omega-3 Fatty Acid Consumption by Mothers during Pregnancy and Lactation Caused Shorter Life Span and Abnormal ABRs in Old Adult Offspring
Church, M. W.; Jen, K-L. C.; Anumba, J.I.; Jackson, D. A.; Adams, B. R.; Hotra, J. W.
Consuming omega-3 fatty acids (?-3 FA) during pregnancy and lactation is beneficial to fetal and infant development and might reduce the incidence and severity of preterm births by prolonging pregnancy. Consequently, supplementing maternal diets with large amounts of ?-3 FA is gaining acceptance. However, both over- and under-supplementation with ?-3 FA can harm offspring development. Adverse fetal and neonatal conditions in general can enhance age-related neural degeneration, shorten life span and cause other adult-onset disorders. We hypothesized that maternal over- and under-nutrition with ?-3 FA would shorten the offspringÆs life span and enhance neural degeneration in old adulthood. To test these hypotheses, female Wistar rats were randomly assigned to one of the three diet conditions starting from day 1 of pregnancy through the entire period of pregnancy and lactation. The three diets were Control ?-3 FA (?-3/?-6 ratio ~ 0.14), Excess ?-3 FA (?-3/?-6 ratio ~ 14.5) and Deficient ?-3 FA (?-3/?-6 ratio ~ 0% ratio). When possible, one male and female offspring from each litter were assessed for life span and sensory/neural degeneration (n=15 litters/group). The Excess offspring had shorter life spans compared to their Control and Deficient cohorts (mean▒SEM=506▒24, 601▒14 and 585▒21 days, p?0.004) when the study terminated on postnatal day 640. The Excess offspring had a higher incidence of presbycusis than the Control and Deficient groups (33.3, 4.3 and 4.5%, p=0.011) and a persistence of other sensory/neurological abnormalities and lower body weights in old adulthood. In conclusion, ?-3 FA over-nutrition or imbalance during pregnancy and lactation had adverse effects on life span and sensory/neurological function in old adulthood. The adverse outcomes in the Excess offspring were likely due to a ōnutritional toxicityö during fetal and/or neonatal development that programmed them for life-long health disorders. The health implication is that consuming or administering large amounts of ?-3 FA during pregnancy and lactation seems inadvisable because of adverse effects on the offspring. PMID:19818397
Effect of delta-sleep inducing peptide-containing preparation Deltaran on biomarkers of aging, life span and spontaneous tumor incidence in female SHR mice.
Popovich, Irina G; Voitenkov, Boris O; Anisimov, Vladimir N; Ivanov, Vadim T; Mikhaleva, Inessa I; Zabezhinski, Mark A; Alimova, Irina N; Baturin, Dmitri A; Zavarzina, Natalia Yu; Rosenfeld, Svetlana V; Semenchenko, Anna V; Yashin, Anatoli I
From the age of 3 months until their natural deaths, female Swiss-derived SHR mice were subcutaneously injected 5 consecutive days every month with 0.1 ml of normal saline (control) or with 2.5 microg/mouse (approximately 100 microg/kg) of delta-sleep inducing peptide (DSIP, Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu) as the preparation Deltaran solved in 0.1 ml of saline. There were 54 mice in each group. The results of this study show that the treatment with Deltaran did not influence food consumption, but decreased the body weight of mice; it slowed down the age-related switching-off of estrous function; it decreased by 22.6% the frequency of chromosome aberrations in bone marrow cells; it did not influence mean life span; and it increased by 17.1% life span of the last 10% of the survivors and by 24.1% maximum life span in comparison with the control group. We also found that treatment with Deltaran significantly decreased total spontaneous tumor incidence (by 2.6-fold), mainly mammary carcinomas and leukemias in mice as compared with the control group. This is the first report on geroprotector and anticarcinogenic effect of DSIP-containing preparation Deltaran. PMID:12782416
TSG (2,3,5,4?-Tetrahydroxystilbene-2-O-?-D-glucoside) from the Chinese Herb Polygonum multiflorum Increases Life Span and Stress Resistance of Caenorhabditis elegans
B³chter, Christian; Zhao, Liang; Fritz, Gerhard; Proksch, Peter
2,3,5,4?-Tetrahydroxystilbene-2-O-?-D-glucoside (TSG) was isolated from Polygonum multiflorum, a plant which is traditionally used as an anti-ageing drug. We have analysed ageing-related effects of TSG in the model organism C. elegans in comparison to resveratrol. TSG exerted a high antioxidative capacity both in a cell-free assay and in the nematode. The antioxidative capacity was even higher compared to resveratrol. Presumably due to its antioxidative effects, treatment with TSG decreased the juglone-mediated induction of the antioxidative enzyme SOD-3; the induction of the GST-4 by juglone was diminished slightly. TSG increased the resistance of C. elegans against lethal thermal stress more prominently than resveratrol (50??M TSG increased mean survival by 22.2%). The level of the ageing pigment lipofuscin was decreased after incubation with the compound. TSG prolongs the mean, median, and maximum adult life span of C. elegans by 23.5%, 29.4%, and 7.2%, respectively, comparable to the effects of resveratrol. TSG-mediated extension of life span was not abolished in a DAF-16 loss-of-function mutant strain showing that this ageing-related transcription factor is not involved in the effects of TSG. Our data show that TSG possesses a potent antioxidative capacity, enhances the stress resistance, and increases the life span of the nematode C. elegans.
Flow cytometric analysis of material-induced platelet activation in a canine model: elevated microparticle levels and reduced platelet life span.
Gemmell, C H; Yeo, E L; Sefton, M V
Assessment of material-induced platelet activation is important given that it is thought to be a major mechanism of biomaterials thrombogenicity. We monitored, by flow cytometry, platelet microparticle (MP) levels in the circulation during the connection of polyvinyl alcohol (PVA) hydrogel and polyethylene (PE) test segments (3.18 mm ID, 20 and 50 cm L) to our chronically shunted beagle dogs. We report that circulating microparticle levels were dependent on test segment material, length, and time. The connection of 50-cm lengths of PVA hydrogel test segments led to MP levels two to three times greater than background at 48 h, while the connection of polyethylene test segments did not lead to elevated microparticle levels. MP levels were near background 24 h after removal of the PVA test segment. To determine platelet life span during the connection of test segments, platelets were labeled in vivo with biotin and their disappearance monitored flow cytometrically. While platelet life span for shunted dogs (no test segment) was 4.7 +/- 0.2 days, the connection of PVA hydrogel test segments led to a platelet life span of < 2 days. PMID:9358309
Loss of Ubp3 increases silencing, decreases unequal recombination in rDNA, and shortens the replicative life span in Saccharomyces cerevisiae
ųling, David; Masoom, Rehan; Kvint, Kristian
Ubp3 is a conserved ubiquitin protease that acts as an antisilencing factor in MAT and telomeric regions. Here we show that ubp3? mutants also display increased silencing in ribosomal DNA (rDNA). Consistent with this, RNA polymerase II occupancy is lower in cells lacking Ubp3 than in wild-type cells in all heterochromatic regions. Moreover, in a ubp3? mutant, unequal recombination in rDNA is highly suppressed. We present genetic evidence that this effect on rDNA recombination, but not silencing, is entirely dependent on the silencing factor Sir2. Further, ubp3? sir2? mutants age prematurely at the same rate as sir2? mutants. Thus our data suggest that recombination negatively influences replicative life span more so than silencing. However, in ubp3? mutants, recombination is not a prerequisite for aging, since cells lacking Ubp3 have a shorter life span than isogenic wild-type cells. We discuss the data in view of different models on how silencing and unequal recombination affect replicative life span and the role of Ubp3 in these processes. PMID:24760971
A structured population model suggests that long life and post-reproductive lifespan promote the evolution of cooperation.
Ross, Caitlin; Rychtß?, Jan; Rueppell, Olav
Social organization correlates with longevity across animal taxa. This correlation has been explained by selection for longevity by social evolution. The reverse causality is also conceivable but has not been sufficiently considered. We constructed a simple, spatially structured population model of asexually reproducing individuals to study the effect of temporal life history structuring on the evolution of cooperation. Individuals employed fixed strategies of cooperation or defection towards all neighbours in a basic Prisoner's Dilemma paradigm. Individuals aged and transitioned through different life history stages asynchronously without migration. An individual's death triggered a reproductive event by one immediate neighbour. The specific neighbour was chosen probabilistically according to the cumulative payoff from all local interactions. Varying the duration of pre-reproductive, reproductive, and post-reproductive life history stages, long-term simulations allowed a systematic evaluation of the influence of the duration of these specific life history stages. Our results revealed complex interactions among the effects of the three basic life history stages and the benefit to defect. Overall, a long post-reproductive stage promoted the evolution of cooperation, while a prolonged pre-reproductive stage has a negative effect. In general, the total length of life also increased the probability of the evolution of cooperation. Thus, our specific model suggests that the timing of life history transitions and total duration of life history stages may affect the evolution of cooperative behaviour. We conclude that the causation of the empirically observed association of life expectancy and sociality may be more complex than previously realized. PMID:25637763
Early-life reproduction is associated with increased mortality risk but enhanced lifetime fitness in pre-industrial humans.
Hayward, Adam D; Nenko, Ilona; Lummaa, Virpi
The physiology of reproductive senescence in women is well understood, but the drivers of variation in senescence rates are less so. Evolutionary theory predicts that early-life investment in reproduction should be favoured by selection at the cost of reduced survival and faster reproductive senescence. We tested this hypothesis using data collected from preindustrial Finnish church records. Reproductive success increased up to age 25 and was relatively stable until a decline from age 41. Women with higher early-life fecundity (ELF; producing more children before age 25) subsequently had higher mortality risk, but high ELF was not associated with accelerated senescence in annual breeding success. However, women with higher ELF experienced faster senescence in offspring survival. Despite these apparent costs, ELF was under positive selection: individuals with higher ELF had higher lifetime reproductive success. These results are consistent with previous observations in both humans and wild vertebrates that more births and earlier onset of reproduction are associated with reduced survival, and with evolutionary theory predicting trade-offs between early reproduction and later-life survival. The results are particularly significant given recent increases in maternal ages in many societies and the potential consequences for offspring health and fitness. PMID:25740893
Use of a Modified Reproductive Life Plan to Improve Awareness of Preconception Health in Women with Chronic Disease
Mittal, Pooja; Dandekar, Aparna; Hessler, Danielle
Objective: Chronic diseases such as hypertension, diabetes, and obesity pose unique reproductive challenges for women. Preconception health results in improved reproductive outcomes. We designed an interventional study testing the use of a reproductive life plan to improve knowledge of preconception and contraception health in women with chronic diseases. Methods: Primarily underserved, English-and Spanish-speaking women aged 18 to 40 years with active diabetes, hypertension, or obesity were recruited. We developed a revised reproductive life plan specific to these diseases. Two resident physicians performed reproductive plan counseling. Pre- and postcounseling surveys were administered to evaluate knowledge and attitudes about chronic disease and the effects on a potential pregnancy. Results: Twenty-seven women (average age = 31 years) were surveyed. Of the subjects, 85.2% were obese, 29.6% had hypertension, and 7.4% had diabetes. Significant increases were reported in understanding risks of pregnancy associated with diabetes (p < 0.001), hypertension (p < 0.001), and obesity (p < 0.01). After counseling, women increased their knowledge about a reproductive plan (p < 0.001) and increased support and information to make reproductive health choices (p = 0.001 and p < 0.01, respectively). The largest improvements in postcounseling variables occurred in women with the lowest precounseling test scores and in women without children. Conclusion: A reproductive life plan is a brief, cost-effective preconception and contraception counseling tool in the primary care setting for women with chronic diseases. This tool increases knowledge about reproductive health and enables women with chronic diseases to make informed decisions about their reproductive future. PMID:24867547
Exploring the performance effects of visible attribute diversity: the moderating role of span of control and organizational life cycle
Orlando C. Richard; David Ford; Kiran Ismail
Research on how cultural diversity ¢ especially visible attributes such as race and gender ¢ impacts organizational performance remains practically nonexistent. We examine the effect of racial diversity and gender diversity on firm performance utilizing a contingency framework. Empirical findings from a field study support the hypothesized contingent effects of an organization's structure, specifically managerial span of control, on both
Antioxidant capacity of "Mexican arnica" Heterotheca inuloides Cass natural products and some derivatives: their anti-inflammatory evaluation and effect on C. elegans life span.
RodrĒguez-Chßvez, Josķ Luis; Coballase-Urrutia, Elvia; Nieto-Camacho, Antonio; Delgado-Lamas, Guillermo
It has been suggested that the accumulation of biomolecular damage caused by reactive oxygen species (ROS) contributes to aging. The antioxidant activity is related to the ability of certain compounds to protect against the potentially harmful effect of processes or reactions involving ROS. This ability is associated with the termination of free radical propagation in biological systems. From Heterotheca inuloides various compounds which have shown to possess antioxidant capacity and scavenging ROS. The aim of this study was to determine the antioxidant capacity of additional natural components isolated from H. inuloides and some semisynthetic derivatives, their anti-inflammatory activity and the effect on Caenorhabditis elegans nematode life span. Compounds showed ability to inhibit various biological processes such as lipid peroxidation, scavenge nonbiological important oxidants such as (1)O2, OH(?), H2O2, and HOCl and scavenge non biological stable free radicals (DPPH). Some cadinane type compounds showed possess antioxidant, ROS scavenging capacity, anti-inflammatory activity, and effect on the C. elegans life span. Flavonoid type compounds increased the life of the nematode and quercetin was identified as the compound with the greatest activity. The modification of chemical structure led to a change in the antioxidant capacity, the anti-inflammatory activity, and the survival of the worm. PMID:25821555
Reproductive problems directly attributable to long-term captivity--asymmetric reproductive aging.
Hermes, R; Hildebrandt, T B; G÷ritz, F
Problems attributable to long-term captivity have been identified and are responsible for the difficulties in establishing successful reproduction in captive populations of wildlife, specifically, elephants and rhinoceroses. Historically, non-reproductive periods of 10-15 years in nulliparous female rhinoceroses and elephants have not been considered problematic. New evidence suggests that prolonged exposure to endogenous sex steroids and that long stretches of non-reproductive periods induce asymmetric reproductive aging in captive animals. The consequences are reduced fertility, shortened reproductive life-span and, eventually, irreversible acyclicity. Although age-related reproductive lesions have also been documented in male rhinoceroses, they continue to maintain a longer reproductive life-span than females. Since human and domestic animal models have already indicated that early pregnancy provides natural protective mechanism against asymmetric reproductive aging processes and premature senescence, it is imperative that appropriate counter measures such as assisted reproductive technologies (ART) be utilized to ensure early pregnancy in captive animals for their preservation and to ensure increased genetic diversity of the captive populations. PMID:15271443
Flashbulb Memories and Posttraumatic Stress Reactions Across the Life-Span: Age-related effects of the German Occupation of Denmark during WWII
Berntsen, Dorthe; Rubin, David C.
A representative sample of older Danes were interviewed about experiences from the German occupation of Denmark in WWII. The number of participants with flashbulb memories for the German invasion (1940) and capitulation (1945) increased with participantsÆ age at the time of the events up to age 8. Among participants under 8 years at the time of their most traumatic event, age at the time correlated positively with current level of posttraumatic stress reactions, vividness of stressful memories and their centrality to life-story and identity. These findings were replicated in Study 2 for self-nominated stressful events sampled from the entire life span using a representative sample of Danes born after 1945. The results are discussed in relation to Posttraumatic Stress Disorder (PTSD) and childhood amnesia. PMID:16594798
PRETEX (Halifax NS) #1 1054 1999 Mar 05 10:59:16
Feb 16, 2007 ... Show that the set of all solutions to the nonhomoge- ... In this system, we view x1 and x2 as fixed, while the variables we must solve for ..... As another illustration, two different spanning sets for V = M2(R) were given in Exam-.
Transcriptional remodeling in response to transfer upon carbon-limited or metformin-supplemented media in S. cerevisiae and its effect on chronological life span.
Borklu-Yucel, Esra; Eraslan, Serpil; Ulgen, Kutlu O
One of the factors affecting chronological life span (CLS) in budding yeast is nutrient, especially carbon limitation. Aside from metabolites in the growth medium such as glucose, amino acids, and acetic acid, many pharmaceuticals have also been proven to alter CLS. Besides their impact on life span, these drugs are also prospective chemicals to treat the age-associated diseases, so the identification of their action mechanism and their potential side effects is of crucial importance. In this study, the effects of caloric restriction and metformin, a dietary mimetic pharmaceutical, on yeast CLS are compared. Saccharomyces cerevisiae cells grown in synthetic dextrose complete (SDC) up to mid-exponential phase were either treated with metformin or were subjected to glucose limitation. The impacts of these perturbations were analyzed via transcriptomics, and the common (stimulation of glucose uptake, induction of mitochondrial maintenance, and reduction of protein translation) and divergent (stimulation of aerobic respiration and reprogramming of respiratory electron transport chain (ETC)) cellular responses specific to each treatment were determined. These results revealed that both glucose limitation and metformin treatment stimulate CLS extension and involve the mitochondrial function, probably by creating an efficient mitochondria-to-nucleus signaling of either aerobic respiration or ETC signaling stimulation, respectively. PMID:26099330
Adenovirus type 12 early region 1B 54K protein significantly extends the life span of normal mammalian cells in culture.
Gallimore, P H; Lecane, P S; Roberts, S; Rookes, S M; Grand, R J; Parkhill, J
The life span of normal human cells in culture is extended by two to four total life spans following retrovirus-mediated transfer of the adenovirus type 12 E1B 54,000-molecular-weight protein (54K protein). This extension of the in vitro growth potential was accomplished without any of the obvious changes in morphology or growth properties that are usually associated with viral transformation. These 54K+ cells escape the normal senescence checkpoint (M1) and show a very extended secondary growth phase. The 54K+ human cells eventually enter crisis (M2), which does not appear to be due to either telomere attrition or the activation of the senescence-associated proteins p21SdilCipIWaf1 and p16INK4A. Even in the absence of telomerase activity, high-molecular-weight heterogeneous telomeres are produced and maintained in both 54K+ adult dermal fibroblasts and embryo kidney cells, indicating that the 54K protein may interfere with the normal metabolism of telomeric structures during cell division. These findings are discussed with reference to the known ability of the 54K protein to influence p53 function. PMID:9261385
Reproductive versus somatic tissue growth during the life cycle of the cuttlefish Sepia pharaonis Ehrenberg, 1831
Howaida R. Gabr; Roger T. Hanlon; Salah G. El-Etreby; Mahmoud H. Hanafy
The effect of maturation on relative growth of somatic tissues was investigated by measuring and compar- ing monthly changes in dry weight of somatic tissues and reproductive or- gans. In both sexes, reproductive tis- sues grew in relation to total body mass; at maturity female reproductive tissue was 16% of total dry body mass, whereas male reproductive tissue was 2.6%.
The amphipod Corophium multisetosum (Corophiidae) in Ria de Aveiro (NW Portugal). I. Life history and aspects of reproductive biology
M. R. Cunha; J. C. Sorbe; M. H. Moreira
The population of Corophium multisetosum Stock, 1952 in AreŃo displayed a semiannual, iteroparous life history. Mean longevity was ?6?mo, with the estimated life\\u000a span longer for overwintering individuals born in autumn than for individuals born in spring. Length-frequency data indicated\\u000a that the length increment per moult is probably higher in males than females; however females moulted more frequently and\\u000a achieved
The use of fractal dimension calculation algorithm to determine the nature of autobiographical memories distribution across the life span
NASA Astrophysics Data System (ADS)
Mitina, Olga V.; Nourkova, Veronica V.
In the given research we offer the technique for the calculation of the density of events which people retrieve from autobiographical memory. We wanted to prove a non-uniformity nature of memories distribution in the course of time and were interested with the law of distribution of these events during life course.
Male alternative reproductive behaviours in a Mediterranean wrasse, Symphodus ocellatus: Evidence from otoliths for multiple life-history pathways
Suzanne H. Alonzo; Michael Taborsky; Peter Wirtz
Although alternative reproductive behaviours have been studied extensively, it has only been possible in a few cases to document the underlying life-history pathways and factors that determine their expression. In Symphodus ocellatus, a Mediterranean wrasse, males adopt a variety of behaviours. Within a season, they may invest in territory defence, nest building and broodcare (nesting males); join nesting males in
Midwives' adoption of the reproductive life plan in contraceptive counselling: a mixed methods study
Stern, J.; Bodin, M.; Grandahl, M.; Segeblad, B.; Axķn, L.; Larsson, M.; Tydķn, T.
STUDY QUESTION How is the reproductive life plan (RLP) adopted in midwifery contraceptive counselling? SUMMARY ANSWER A majority of midwives adopted the RLP in their counselling, had predominantly positive experiences and considered it a feasible tool for promoting reproductive health. WHAT IS KNOWN ALREADY The RLP is a health-promoting tool recommended by the Centers for Disease Control and Prevention in the USA for improving preconception health. It was recently used in a clinical setting in Sweden and was found to increase women's knowledge about fertility and to influence women's wishes to have their last child earlier in life. STUDY DESIGN, SIZE, DURATION An exploratory mixed methods study among 68 midwives who provided contraceptive counselling in primary health care to at least 20 women each during the study period. Midwives received an introduction and materials for using the RLP in contraceptive counselling. Three months later, in the spring of 2014, they were invited to complete a questionnaire and participate in a focus group interview about their adoption of the RLP. PARTICIPANTS/MATERIALS, SETTING, METHODS Data collection was through a questionnaire (n = 53 out of 68; participation rate 78%) and five focus group interviews (n = 22). Participants included both younger and older midwives with longer and shorter experiences of contraceptive counselling in public and private health care in one Swedish county. Quantitative data were analysed for differences between users and non-users, and qualitative data were analysed by qualitative content analysis to explore the midwives experiences and opinions of using the RLP. MAIN RESULTS AND THE ROLE OF CHANCE Sixty-eight per cent of midwives had used the RLP in their contraceptive counselling. Four categories emerged through the focus group interviews: (i) A predominantly positive experience; (ii) The RLPŚa health-promoting tool; (iii) individual and societal factors influence the RLP counselling; and (4) long-term implementation comprises opportunities, risks and needs. The most common reason for not using the RLP was lack of information. LIMITATIONS, REASONS FOR CAUTION There was general lack of experience of using the RLP with women from different cultural backgrounds, with non-Swedish speaking women and, when a partner was present. Due to the non-random sample, the limited knowledge about non-responders and a short follow-up period, results apply to short-term implementations and might not fully apply to long-term implementation. WIDER IMPLICATIONS OF THE FINDINGS The use of RLP in contraceptive counselling appears a feasible way of promoting reproductive health. Results from the USA and Sweden indicate it is a promising tool for midwives and other health professionals involved in reproductive counselling, which deserves to be explored in other nations. STUDY FUNDING/COMPETING INTEREST(S) Grants were received from the Medical Faculty at Uppsala University and the European Society of Contraception and Reproductive Health. There are no competing interests. TRIAL REGISTRATION NUMBER N/A. PMID:25771220
The Study of Life Review. An Approach to the Investigation of Intellectual Development across the Life Span. Studien und Berichte 47.
ERIC Educational Resources Information Center
Staudinger, Ursula M.
A study looked for age differences in the quality of responses to the Life Review Task (LRT), studied the LRT itself as a tool for exploring wisdom and intellectual functioning in adulthood, and considered personality characteristics and life experience as alternative predictors of response quality. Sixty-three West German women of different agesģ
Assessing the burden of sexual and reproductive ill-health: questions regarding the use of disability-adjusted life years.
AbouZahr, C.; Vaughan, J. P.
The use of the disability-adjusted life year (DALY) as the unit in which to calculate the burden of disease associated with reproductive ill-health has given rise to considerable debate. Criticisms include the failure to address the problem of missing and inadequate epidemiological data, inability to deal adequately with co-morbidities, and lack of transparency in the process of ascribing disability weights to sexual and reproductive health conditions. Many of these criticisms could be addressed within the current DALY framework and a number of suggestions to do so are made. These suggestions include: (1) developing an international research strategy to determine the incidence and prevalence of reproductive ill-health and diseases, including the risk of long-term complications; (2) undertaking a research strategy using case studies, population-based surveillance data and longitudinal studies to identify, evaluate and utilize more of the existing national data sources on sexual and reproductive health; (3) comprehensively mapping the natural history of sexual and reproductive health conditions--in males and in females--and their sequelae, whether physical or psychological; (4) developing valuation instruments that are adaptable for both chronic and acute health states, that reflect a range of severity for each health state and can be modified to reflect prognosis; (5) undertaking a full review of the DALY methodology to determine what changes may be made to reduce sources of methodological and gender bias. Despite the many criticisms of the DALY as a measurement unit, it represents a major conceptual advance since it permits the combination of life expectancy and levels of dysfunction into a single measure. Measuring reproductive ill-health by counting deaths alone is inadequate for a proper understanding of the dimensions of the problem because of the young age of many of the deaths associated with reproductive ill-health and the large component of years lived with disability from many of the associated conditions. PMID:10859859
Personality, Self-Rated Health and Subjective Age in a Life-Span Sample: The Moderating Role of Chronological Age
Stephan, Yannick; Demulier, Virginie; Terracciano, Antonio
The present study tested whether chronological age moderates the association between subjective age and self-rated health and personality in a community-dwelling lifespan sample (N=1,016; age-range: 18¢91). Self-rated health, extraversion, and openness to experience were associated with a younger subjective age at older ages. Conscientious individuals felt more mature early in life. Conscientiousness, neuroticism, and agreeableness were not related to subjective age at older ages. These findings suggest that with aging self-rated health and personality traits are increasingly important for subjective age. PMID:22582885
A unifying perspective on personality pathology across the life span: Developmental considerations for the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders
Proposed changes in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) include replacing current personality disorder (PD) categories on Axis II with a taxonomy of dimensional maladaptive personality traits. Most of the work on dimensional models of personality pathology, and on personality disorders per se, has been conducted on young and middle-aged adult populations. Numerous questions remain regarding the applicability and limitations of applying various PD models to early and later life. In the present paper, we provide an overview of such dimensional models and review current proposals for conceptualizing PDs in DSM-V. Next, we extensively review existing evidence on the development, measurement, and manifestation of personality pathology in early and later life focusing on those issues deemed most relevant for informing DSM-V. Finally, we present overall conclusions regarding the need to incorporate developmental issues in conceptualizing PDs in DSM-V and highlight the advantages of a dimensional model in unifying PD perspectives across the life span. PMID:19583880
Early life stress shapes female reproductive strategy through eggshell pigmentation in Japanese quail.
Duval, Camille; Zimmer, Cķdric; MikÜĒk, Ivan; Cassey, Phillip; Spencer, Karen A
Physiological constraints on colouration have been widely reported; especially in birds, which trade-off antioxidant responses against colourful costly signals. One female extended phenotypic trait, which might also highlight important physiological trade-offs, is the pigmentation of their eggshells. In ground-nesting species, producing eggs that are visually undetectable by predators is the best camouflage strategy. However, the condition-dependence of eggshell pigmentation, and the pigments role in oxidative stress, may constrain females to trade-off between their antioxidant capacity and maximising the camouflage of their eggs when they deposit eggshell pigments. Developmental stress is one factor that influences female antioxidant capacity, and could lead to variations in eggshell pigmentation that might have crucial consequences on individual fitness if egg crypsis is compromised especially under stressful conditions. We investigated the interaction between developmental and breeding conditions with respect to eggshell pigmentation in Japanese quail. We studied 30 females that bred under both control and stressful conditions, and were exposed to pre- and/or post-natal stress, or neither. Pre- and post-natal stress independently influenced eggshell pigmentation strategies under stressful breeding conditions. Under stressful reproduction, eggshell protoporphyrin concentration and maculation were affected by pre-natal stress, whereas eggshell reflectance and biliverdin concentration were influenced by post-natal stress. These changes may reflect potential adaptive strategies shaped by developmental stress, but additional data on the benefit of egg crypsis in quail, combined with studies on the role of both pigments on chick survival, will help to clarify whether early life stress can enhance fitness through eggshell pigmentation when developmental and reproductive environments match. PMID:25169834
Immortalization of Human Fetal Cells: The Life Span of Umbilical Cord Blood-derived Cells Can Be Prolonged without Manipulating p16INK4a/RB Braking PathwayD?
Terai, Masanori; Uyama, Taro; Sugiki, Tadashi; Li, Xiao-Kang; Umezawa, Akihiro; Kiyono, Tohru
Human umbilical cord blood-derived mesenchymal stem cells (UCBMSCs) are expected to serve as an excellent alternative to bone marrow-derived human mesenchymal stem cells. However, it is difficult to study them because of their limited life span. To overcome this problem, we attempted to produce a strain of UCBMSCs with a long life span and to investigate whether the strain could maintain phenotypes in vitro. UCBMSCs were infected with retrovirus carrying the human telomerase reverse transcriptase (hTERT) to prolong their life span. The UCBMSCs underwent 30 population doublings (PDs) and stopped dividing at PD 37. The UCBMSCs newly established with hTERT (UCBTERTs) proliferated for >120 PDs. The p16INK4a/RB braking pathway leading to senescence can be inhibited by introduction of Bmi-1, a polycomb-group gene, and human papillomavirus type 16 E7, but the extension of the life span of the UCBMSCs with hTERT did not require inhibition of the p16INK4a/RB pathway. The characteristics of the UCBTERTs remained unchanged during the prolongation of life span. UCBTERTs provide a powerful model for further study of cellular senescence and for future application to cell-based therapy by using umbilical cord blood cells. PMID:15647378
Effects of triclosan on the early life stages and reproduction of medaka Oryzias latipes and induction of hepatic vitellogenin
Hiroshi Ishibashi; Naomi Matsumuraa; Masashi Hirano; Munekazu Matsuokaa; Hideki Shiratsuchi; Yasuhiro Ishibashi; Yuji Takao; Koji Arizono
Triclosan (2,4,4?-trichloro-2?-hydroxydiphenyl ether) is widely used as antibacterial agent in various industrial products, such as textile goods, soap, shampoo, liquid toothpaste and cosmetics, and often detected in wastewater effluent. In this study, the effects of TCS on the early life stages and reproduction of medaka (Oryzias latipes) were investigated. The 96-h median lethal concentration value of TCS for 24-h-old larvae
Gene pathways that delay Caenorhabditis elegans reproductive senescence.
Wang, Meng C; Oakley, Holly D; Carr, Christopher E; Sowa, Jessica N; Ruvkun, Gary
Reproductive senescence is a hallmark of aging. The molecular mechanisms regulating reproductive senescence and its association with the aging of somatic cells remain poorly understood. From a full genome RNA interference (RNAi) screen, we identified 32 Caenorhabditis elegans gene inactivations that delay reproductive senescence and extend reproductive lifespan. We found that many of these gene inactivations interact with insulin/IGF-1 and/or TGF-? endocrine signaling pathways to regulate reproductive senescence, except nhx-2 and sgk-1 that modulate sodium reabsorption. Of these 32 gene inactivations, we also found that 19 increase reproductive lifespan through their effects on oocyte activities, 8 of them coordinate oocyte and sperm functions to extend reproductive lifespan, and 5 of them can induce sperm humoral response to promote reproductive longevity. Furthermore, we examined the effects of these reproductive aging regulators on somatic aging. We found that 5 of these gene inactivations prolong organismal lifespan, and 20 of them increase healthy life expectancy of an organism without altering total life span. These studies provide a systemic view on the genetic regulation of reproductive senescence and its intersection with organism longevity. The majority of these newly identified genes are conserved, and may provide new insights into age-associated reproductive senescence during human aging. PMID:25474471
Gene Pathways That Delay Caenorhabditis elegans Reproductive Senescence
Wang, Meng C.; Oakley, Holly D.; Carr, Christopher E.; Sowa, Jessica N.; Ruvkun, Gary
Reproductive senescence is a hallmark of aging. The molecular mechanisms regulating reproductive senescence and its association with the aging of somatic cells remain poorly understood. From a full genome RNA interference (RNAi) screen, we identified 32 Caenorhabditis elegans gene inactivations that delay reproductive senescence and extend reproductive lifespan. We found that many of these gene inactivations interact with insulin/IGF-1 and/or TGF-? endocrine signaling pathways to regulate reproductive senescence, except nhx-2 and sgk-1 that modulate sodium reabsorption. Of these 32 gene inactivations, we also found that 19 increase reproductive lifespan through their effects on oocyte activities, 8 of them coordinate oocyte and sperm functions to extend reproductive lifespan, and 5 of them can induce sperm humoral response to promote reproductive longevity. Furthermore, we examined the effects of these reproductive aging regulators on somatic aging. We found that 5 of these gene inactivations prolong organismal lifespan, and 20 of them increase healthy life expectancy of an organism without altering total life span. These studies provide a systemic view on the genetic regulation of reproductive senescence and its intersection with organism longevity. The majority of these newly identified genes are conserved, and may provide new insights into age-associated reproductive senescence during human aging. PMID:25474471
Resource allocation in a social wasp: effects of breeding system and life cycle on reproductive decisions.
Johnson, Elizabeth L; Cunningham, Tyler W; Marriner, Sarah M; Kovacs, Jennifer L; Hunt, Brendan G; Bhakta, Dimpal B; Goodisman, Michael A D
Organisms must make important decisions on how to allocate resources to reproduction. We investigated allocation decisions in the social wasp Vespula maculifrons to understand how social insects make reproductive choices. We first determined how annual colonies apportioned resources to growth and reproduction by analysing developing brood. In contrast to expectations, colonies invested in both growth (workers) and reproduction (males) simultaneously. In addition, colonies showed evidence of producing males in pulses and reversing their reproductive choices by decreasing investment in males late in the season. This reversal is consistent with theory suggesting that colonies decrease production in males if fitness of late emerging males is low. To further investigate reproductive decisions within colonies, we determined if the male mates of multiply-mated queens varied in their reproductive success over time. Sperm use by queens did vary over time suggesting that male success may depend on sperm clumping within the female reproductive tract. Finally, we tested if colony sex ratio conformed to expectations under kin selection theory that nestmate relatedness would positively correlate with investment in new queens if workers controlled sex allocation. Surprisingly, the proportion of queens produced by colonies was negatively correlated with nestmate relatedness, suggesting that allocation may be shaped by advantages arising from increased genetic diversity resulting from multiple mating by queens. Overall, our study suggests that the reproductive decisions of colonies are flexible and may depend both on environmental cues arising from energetic needs of the colony and genetic cues arising from mating behaviours of queens. PMID:19500245
Survival, growth, and various measures of reproductive performance were examined for an estuarine mysid, Mysidopsis bahia, throughout its life cycle during exposure to the organophosphate insecticide, fenthion. Both individual fecundity of females and total population production ...
Life-history patterns and sociality in canids: Body size, reproduction, and behavior
Mare Bekoff; Judy Diamond; Jeffry B. Mitton
Empirical associations among co-adapted traits such as body size and patterns of reproduction, development, and behavior are unknown for most animal species, despite numerous theories suggesting otherwise. One way to study these complex relationships is first to consider closely related species and then to generalize findings to other groups. In the present study, relationships among body size, reproductive patterns, development,
4-[3,5Bis(trimethylsilyl)benzamido] benzoic acid (TAC101) inhibits the intrahepatic spread of hepatocellular carcinoma and prolongs the life-span of tumor-bearing animals
Koji Murakami; Tomokazu Matsuura; Masaki Sano; Akihiro Hashimoto; Kazuhiko Yonekura; Rieko Sakukawa; Yuji Yamada; Ikuo Saiki
We examined the in vivo anti-tumor activity of the benzoic acid derivative, TAC-101 (4-[3,5- bis(trimethylsilyl)benzamido] benzoic acid), for intrahepatic spread of JHH-7 human hepatocellular carci-noma (HCC) cells and its mechanism of action. Oral administration of TAC-101 markedly inhibited liver tumor of JHH-7 cells and prolonged the life-span of tumor-bearing mice without affecting the body weight. The life-prolonging effect of TAC-101
Increased production of mitochondrial reactive oxygen species and reduced adult life span in an insecticide-resistant strain of Anopheles gambiae
Otali, Dennis; Novak, Robert J.; Wan, Wen; Bu, Su; Moellering, Douglas R.; De Luca, Maria
Control of the malaria vector An. gambiae is still largely obtained through chemical intervention using pyrethroids, such as permethrin. However, strains of An. gambiae that are resistant to the toxic effects of pyrethroids have become widespread in several endemic areas over the last decade. The objective of this study was to assess differences in five life-history traits (larval developmental time and the body weight, fecundity, hatch rate, and longevity of adult females) and energy metabolism between a strain of An. gambiae that is resistant to permethrin (RSP), due to knockdown resistance and enhanced metabolic detoxification, and a permethrin susceptible strain reared under laboratory conditions. We also quantified the expression levels of five antioxidant enzyme genes: GSTe3, CAT, GPXH1, SOD1, and SOD2. We found that the RSP strain had a longer developmental time than the susceptible strain. Additionally, RSP adult females had higher wet body weight and increased water and glycogen levels. Compared to permethrin susceptible females, RSP females displayed reduced metabolic rate and mitochondrial coupling efficiency and higher mitochondrial ROS production. Furthermore, despite higher levels of GSTe3 and CAT transcripts, RSP females had a shorter adult life span than susceptible females. Collectively, these results suggest that permethrin resistance alleles might affect energy metabolism, oxidative stress, and adult survival of An. gambiae. However, because the strains used in this study differ in their genetic backgrounds, the results need to be interpreted with caution and replicated in other strains in order to have significant implications for malaria transmission and vector control. PMID:24555527
Cardiovascular determinants of life span
Yi Shi; Giovanni G. Camici; Thomas F. L³scher
The prevalence of cardiovascular diseases rises with aging and is one of the main causes of mortality in western countries.\\u000a In view of the progressively aging population, there is an urge for a better understanding of age-associated cardiovascular\\u000a diseases and its underlying molecular mechanisms. The risk factors for cardiovascular diseases include unhealthy diet, diabetes,\\u000a obesity, smoking, alcohol consumption, physical inactivity,
Life span in online communities
NASA Astrophysics Data System (ADS)
Grabowski, A.; Kosi?ski, R. A.
Recently online communities have attracted great interest and have become an important medium of information exchange between users. The aim of this work is to introduce a simple model of the evolution of online communities. This model describes (a) the time evolution of usersÆ activity in a web service, e.g., the time evolution of the number of online friends or written posts, (b) the time evolution of the degree distribution of a social network, and (c) the time evolution of the number of active users of a web service. In the second part of the paper we investigate the influence of the usersÆ lifespan (i.e., the total time in which they are active in an online community) on the process of rumor propagation in evolving social networks. Viral marketing is an important application of such method of information propagation.
Human Keratinocytes That Express hTERT and Also Bypass a p16INK4a-Enforced Mechanism That Limits Life Span Become Immortal yet Retain Normal Growth and Differentiation Characteristics
Normal human cells exhibit a limited replicative life span in culture, eventually arresting growth by a process termed senescence. Progressive telomere shortening appears to trigger senescence in normal human fibroblasts and retinal pigment epithelial cells, as ectopic expression of the telomerase catalytic subunit, hTERT, immortalizes these cell types directly. Telomerase expression alone is insufficient to enable certain other cell types
Combination of hTERT and bmi-1, E6, or E7 Induces Prolongation of the Life Span of Bone Marrow Stromal Cells from an Elderly Donor without Affecting Their Neurogenic Potentialå
Mori, Taisuke; Kiyono, Tohru; Imabayashi, Hideaki; Takeda, Yukiji; Tsuchiya, Kohei; Miyoshi, Shunichirou; Makino, Hatsune; Matsumoto, Kenji; Saito, Hirohisa; Ogawa, Satoshi; Sakamoto, Michiie; Hata, Jun-Ichi; Umezawa, Akihiro
Murine bone marrow stromal cells differentiate not only into mesodermal derivatives, such as osteocytes, chondrocytes, adipocytes, skeletal myocytes, and cardiomyocytes, but also into neuroectodermal cells in vitro. Human bone marrow stromal cells are easy to isolate but difficult to study because of their limited life span. To overcome this problem, we attempted to prolong the life span of bone marrow stromal cells and investigated whether bone marrow stromal cells modified with bmi-1, hTERT, E6, and E7 retained their differentiated capability, or multipotency. In this study, we demonstrated that the life span of bone marrow stromal cells derived from a 91-year-old donor could be extended and that the stromal cells with an extended life span differentiated into neuronal cells in vitro. We examined the neuronally differentiated cells morphologically, physiologically, and biologically and compared the gene profiles of undifferentiated and differentiated cells. The neuronally differentiated cells exhibited characteristics similar to those of midbrain neuronal progenitors. Thus, the results of this study support the possible use of autologous-cell graft systems to treat central nervous system diseases in geriatric patients. PMID:15923633
Sarconesiopsis magellanica (Diptera: Calliphoridae) life-cycle, reproductive and population parameters using different diets under laboratory conditions.
Pinilla, Yudi T; Patarroyo, Manuel A; Bello, Felio J
Sarconesiopsis magellanica is a forensically relevant necrophagous blowfly that can aid in determining the post-mortem interval (PMI) as it is the first to colonise decomposing corpses. The blowfly has been reported in several South-American countries including Colombia, in high-altitude regions ranging from 1200 to 3100 m above sea level. The present study reports this blowfly's life cycle and an analysis of its reproductive and population parameters under laboratory conditions for the first time. Six successive generations of flies were produced with an average of 65.38% adults emerging with respect to the total number of puparia. The shortest life cycle from egg to adult emergence was found in individuals fed on a lyophilised liver (LL) diet, while the longest one was found in individuals fed with an egg-powdered milk (E-PM) diet; intermediate values were found when the pig liver (PL) diet was tested. The greatest adult longevity was achieved when the PL diet was used, the LL diet giving the shortest. The population parameters based on the horizontal life table were: net reproductive rate (Ro)=447.752▒9.9, mean generational time (Tc)=18.18▒0.38, natural population increase rate (r(m))=0.145 and finite population increase rate (?)=1.398. This blowfly colony represents a valuable asset for both basic and applied studies. Members of the S. magellanica colony so established were used for analysing the life-cycle, reproductive and population parameters, and further medical and forensic application studies are currently underway. PMID:24314544
Reproductive mode and life cycle of the ash dieback pathogen Hymenoscyphus pseudoalbidus.
Gross, A; Zaffarano, P L; Duo, A; Gr³nig, C R
Ash dieback caused by the fungal pathogen Hymenoscyphus pseudoalbidus is currently ravaging in Europe, killing Fraxinus excelsior and Fraxinus angustifolia trees of all age classes. The aim of this work was to elucidate aspects of the reproduction biology of this fungal pathogen and its cryptic, non-pathogenic sister species Hymenoscyphus albidus. The mating type (MAT) locus of both species was identified, partly sequenced and characterized. Whereas a heterothallic MAT organization was detected in H. pseudoalbidus, H. albidus was shown to be structurally homothallic. The molecular MAT determination of H. pseudoalbidus was confirmed by crossing experiments on sterile ash petioles. Crossings of strains exhibiting alternate MAT idiomorphs produced fertile apothecia whereas crosses of strains with identical MAT idiomorphs were never successful. Offspring genotyping with microsatellites (MSs) and the MAT marker confirmed that both parental strains were involved in apothecia formation. In addition, polymorphic MS were shown to follow Mendelian inheritance. However, for yet unknown reasons the MAT ratio of progenies of one successful cross revealed a significant segregation distortion. Based on the MAT sequences of H. pseudoalbidus a multiplex PCR was developed, allowing for a quick and reliable MAT determination. The PCR was applied to screen the MAT ratio of two H. pseudoalbidus populations derived from the country of the disease outbreak in Poland and two populations from the disease periphery in Switzerland. None of the screened populations showed a significant deviation from the 1:1 ratio, expected under random mating. Therefore, an initial clonal distribution through asexually produced conidiospores as observed for other fungal pathogens holds not true for H. pseudoalbidus. Instead, our data is highly supportive for a distribution through ascospores. Leaf petioles collected in the field were thoroughly analyzed for the number of different colonizing strains and their mating behavior. Up to eight different H. pseudoalbidus genotypes were found on a single petiole. Cross-fertilizations of strains on the same petiole and fertilizations of unknown strains from outside were found, indicating that fertilization is mediated by spermatia. The presented study complements our understanding of the life cycle of this highly destructive pathogen. The possibility to perform sexual crosses in the lab provides ample opportunities for further genetic studies of H. pseudoalbidus and related species in the future. PMID:23036580
Patterns of hippocampal-neocortical interactions in the retrieval of episodic autobiographical memories across the entire life-span of aged adults
Viard, Armelle; Lebreton, Karine; Chķtelat, Gaļl; Desgranges, Bķatrice; Landeau, Brigitte; Young, Alan; De La Sayette, Vincent; Eustache, Francis; Piolino, Pascale
We previously demonstrated that Episodic Autobiographical Memories (EAMs) rely on a network of brain regions comprising the medial temporal lobe (MTL) and distributed neocortical regions regardless of their remoteness. The findings supported the model of memory consolidation which proposes a permanent role of MTL during EAM retrieval (Multiple-Trace Theory or MTT) rather than a temporary role (standard model). Our present aim was to expand the results by examining the interactions between the MTL and neocortical regions (or MTL-neocortical links) during EAM retrieval with varying retention intervals. We used an experimental paradigm specially designed to engage aged participants in the recollection of EAMs, extracted from five different time-periods, covering their whole life-span, in order to examine correlations between activation in the MTL and neocortical regions. The nature of the memories was checked at debriefing by means of behavioral measures to control the degree of episodicity and properties of memories. Targeted correlational analyses carried out on the MTL, frontal, lateral temporal and posterior regions revealed strong links between the MTL and neocortex during the retrieval of both recent and remote EAMs, challenging the standard model of memory consolidation and supporting MTT instead. Further confirmation was given by results showing that activation in the left and right hippocampi significantly correlated during the retrieval of both recent and remote memories. Correlations among extra-MTL neocortical regions also emerged for all time-periods, confirming the critical role of the prefrontal, temporal (lateral temporal cortex and temporal pole), precuneus and posterior cingulate regions in EAM retrieval. Overall, this paper emphasizes the role of a bilateral network of MTL and neocortical areas whose activation correlate during the recollection of rich phenomenological recent and remote EAMs. PMID:19338022
Life as a bachelor: quantifying the success of an alternative reproductive tactic in male blue monkeys
Cords, Marina
In species that live in one-male groups, resident males monopolize access to a group of females and are assumed to have higher reproductive success than bachelors. We tested this assumption using genetic, demographic, and behavioral data from 8 groups of wild blue monkeys observed over 10 years to quantify reproduction by residents and bachelors and compare the success of the two tactics. We used maximum-likelihood methods to assign sires to 104 offspring born in the study groups, 36 of which were sired by extra-group males, i.e., residents of neighboring groups and bachelors. Among these extra-group males, high-ranking males (many of whom were neighboring residents) were more likely to sire offspring than low-ranking males, but the time these visiting males spent in the motherÆs group when she conceived (male presence) did not predict their relative success. When bachelors competed for reproduction with other bachelors, neither rank nor male presence during the motherÆs conceptive period affected the probability of siring an offspring, suggesting that highly opportunistic mating with conceptive females is important in bachelor reproduction. In a second analysis, we used long-term data to estimate resident and bachelor reproductive success over the long term, and particularly to determine if there are any circumstances in which a typical bachelor may sire as many offspring as a typical resident during one or two periods of residency. Our findings generally support the assumption of a resident reproductive advantage because in most circumstances, a lifelong bachelor would be unable to sire as many offspring as a resident. However, a bachelor who performs at the average rate in the average number of groups for several years may have similar lifetime reproductive success as a male whose reproduction is limited to one short period of residency, especially in a small group. Our findings suggest that one should not assume a resident reproductive advantage for males in one-male groups in all circumstances. PMID:26131380
Influence of early-life nutrition on mortality and reproductive success during a subsequent famine in a preindustrial population
Hayward, Adam D.; Rickard, Ian J.; Lummaa, Virpi
Individuals with insufficient nutrition during development often experience poorer later-life health and evolutionary fitness. The Predictive Adaptive Response (PAR) hypothesis proposes that poor early-life nutrition induces physiological changes that maximize fitness in similar environments in adulthood and that metabolic diseases result when individuals experiencing poor nutrition during development subsequently encounter good nutrition in adulthood. However, although cohort studies have shown that famine exposure in utero reduces health in favorable later-life conditions, no study on humans has demonstrated the predicted fitness benefit under low later-life nutrition, leaving the evolutionary origins of such plasticity unexplored. Taking advantage of a well-documented famine and unique datasets of individual life histories and crop yields from two preindustrial Finnish populations, we provide a test of key predictions of the PAR hypothesis. Known individuals from fifty cohorts were followed from birth until the famine, where we analyzed their survival and reproductive success in relation to the crop yields around birth. We were also able to test whether the long-term effects of early-life nutrition differed between individuals of varying socioeconomic status. We found that, contrary to predictions of the PAR hypothesis, individuals experiencing low early-life crop yields showed lower survival and fertility during the famine than individuals experiencing high early-life crop yields. These effects were more pronounced among young individuals and those of low socioeconomic status. Our results do not support the hypothesis that PARs should have been favored by natural selection and suggest that alternative models may need to be invoked to explain the epidemiology of metabolic diseases. PMID:23918366
An FXPRLamide Neuropeptide Induces Seasonal Reproductive Polyphenism Underlying a Life-History Tradeoff in the Tussock Moth
Uehara, Hiroshi; Senoh, Yukiko; Yoneda, Kyohei; Kato, Yoshiomi; Shiomi, Kunihiro
The white spotted tussock moth, Orgyia thyellina, is a typical insect that exhibits seasonal polyphenisms in morphological, physiological, and behavioral traits, including a life-history tradeoff known as oogenesis-flight syndrome. However, the developmental processes and molecular mechanisms that mediate developmental plasticity, including life-history tradeoff, remain largely unknown. To analyze the molecular mechanisms involved in reproductive polyphenism, including the diapause induction, we first cloned and characterized the diapause hormone-pheromone biosynthesis activating neuropeptide (DH-PBAN) cDNA encoding the five Phe-X-Pro-Arg-Leu-NH2 (FXPRLa) neuropeptides: DH, PBAN, and ?-, ?-, and ?-SGNPs (subesophageal ganglion neuropeptides). This gene is expressed in neurosecretory cells within the subesophageal ganglion whose axonal projections reach the neurohemal organ, the corpus cardiacum, suggesting that the DH neuroendocrine system is conserved in Lepidoptera. By injection of chemically synthetic DH and anti-FXPRLa antibody into female pupae, we revealed that not only does the Orgyia DH induce embryonic diapause, but also that this neuropeptide induces seasonal polyphenism, participating in the hypertrophy of follicles and ovaries. In addition, the other four FXPRLa also induced embryonic diapause in O. thyellina, but not in Bombyx mori. This is the first study showing that a neuropeptide has a pleiotropic effect in seasonal reproductive polyphenism to accomplish seasonal adaptation. We also show that a novel factor (i.e., the DH neuropeptide) acts as an important inducer of seasonal polyphenism underlying a life-history tradeoff. Furthermore, we speculate that there must be evolutionary conservation and diversification in the neuroendocrine systems of two lepidopteran genera, Orgyia and Bombyx, in order to facilitate the evolution of coregulated life-history traits and tradeoffs. PMID:21887383
The review of published literature and research reports revealed limited data for a few warmwater fish species concerning the impacts of suspended solids and sediments on reproductive success. Laboratory and field studies during the 1930-50s examined direct mortality as the resul...
The pattern of reproductive life in a Berber population of Morocco.
Crognier, E; Bernis, C; Elizondo, S; Varea, C
Reproductive patterns were studied from data collected in 1,450 Berber households in the province of Marrakesh, Morocco in 1984. Women aged 45-49 years had a mean of 8.9 pregnancies to achieve 5.7 living children. Social influences on fertility rates show the importance of tradition, particularly through time-dependent variables such as age at marriage, waiting time to first birth, interbirth intervals, and duration of breastfeeding. Birth control does not appear to affect the tempo of fertility; rather, its main use is to bring the reproductive period to a close. The comparison of two subsamples of women separated by a 25-year interval indicates an actual acceleration of the tempo of fertility by the reduction of waiting time to first birth and of interbirth intervals. The supposed ongoing process of demographic transition is not clearly observed in this population. PMID:8178187
Life history and reproductive potential of the agarophyte Gelidium robustum in California
Ricardo A. Melo; Michael Neushul
The reproductive potential of the tetrasporangial phase of Gelidium robustum was studied for 16 months at two sites off Santa Barbara, California. In all samples tetrasporangial thalli were always more abundant than gametangial ones. Tetratrasporangial sori were present throughout the duration of the study but relative fecundity was highest [300¢400 sori g-1 (w. wt)] in spring\\/summer samples of consecutive years,
Intra-sexual variation in male reproduction in teleost fish: a comparative approach
reproductive tactics can be classified according to their plasticity during the life span of the individuals (i.e., fixed vs. sequential vs. reversible). Furthermore, the differences between morphs within a given species glands. In this paper, we review the available data on four species exhibiting different types of intra
Genetic factors in human reproduction: a trade off between procreation and longevity
Frķdķrique Margo van Dunnķ
Genetic factors play an important role in the regulation of human life span but the exact pathways remain to be elucidated, however they may be interrelated with the regulation of human reproduction. It is argued that an innate cytokine profile supportive of Th1-type T cells favors survival of infectious diseases (with longevity as the ultimate), but women with this profile
Optimal life histories and food web position: linkages among somatic growth, reproductive investment, and mortality
B. J. Shuter; N. P. Lester; J. LaRose; C. F. Purchase; K. Vascotto; G. Morgan; N. C. Collins; P. A. Abrams
Life history variation among 60 Ontario populations of lake trout (Salvelinus namaycush), walleye (Sander vitreus), cisco (Coregonus artedii), and yellow perch (Perca flavescens) is presented and interpreted using a biphasic model of individual growth that specifically accounts for the significant shift in energy allocation that accompanies sexual maturity. We show that the constraints imposed on life history variation by the
Reproductive success in presenescent common gulls (Larus canus): the importance of the last year of life.
Rattiste, Kalev
Survival selection against individuals of inferior quality (measured as breeding success) has been proposed to account for the increase in average reproductive success with advancing age in presenescent birds. This so-called selection hypothesis relies on quality-dependent survival. In the present breeding performance study of common gulls, Larus canus, this assumption was not verified. In particular, omitting the last breeding year from the analysis resulted in the disappearance of the correlation between breeding success and survival. A positive correlation in the full dataset was thus solely based on the poor breeding success of ultimate breeders. Indeed, presenescent individuals were shown to have a specifically low breeding success in their terminal breeding event. The poor success of ultimate breeders thus reflects an abruptly declined condition rather than the birds' overall quality. A comparison of the survival of poor and good performers, involving last-time breeders, thus needs not to be a proper test of the selection hypothesis. Longitudinal analysis revealed a steady increase of individual breeding success until the tenth breeding year. The results suggest that an increase of breeding success with age often found in cross-sectional analyses is primarily a result of age-related improvements of competence and/or increased reproductive effort. PMID:15451696
Reproductive success in presenescent common gulls (Larus canus): the importance of the last year of life.
Rattiste, Kalev
Survival selection against individuals of inferior quality (measured as breeding success) has been proposed to account for the increase in average reproductive success with advancing age in presenescent birds. This so-called selection hypothesis relies on quality-dependent survival. In the present breeding performance study of common gulls, Larus canus, this assumption was not verified. In particular, omitting the last breeding year from the analysis resulted in the disappearance of the correlation between breeding success and survival. A positive correlation in the full dataset was thus solely based on the poor breeding success of ultimate breeders. Indeed, presenescent individuals were shown to have a specifically low breeding success in their terminal breeding event. The poor success of ultimate breeders thus reflects an abruptly declined condition rather than the birds' overall quality. A comparison of the survival of poor and good performers, involving last-time breeders, thus needs not to be a proper test of the selection hypothesis. Longitudinal analysis revealed a steady increase of individual breeding success until the tenth breeding year. The results suggest that an increase of breeding success with age often found in cross-sectional analyses is primarily a result of age-related improvements of competence and/or increased reproductive effort. PMID:15451696
Quality of life, reproduction and sexuality after stem cell transplantation with partially T-cell-depleted grafts and after conditioning with a regimen including total body irradiation
J. J. M. Claessens; C. C. M. Beerendonk; A. V. M. B. Schattenberg; AVMB Schattenberg
Thirty-four men and 36 women (median age 43 and 45 years, respectively) underwent stem cell transplantation (SCT) for acute leukaemia in first complete remission or chronic myelogenous leukaemia in first chronic phase between 1981 and 2001 from HLA-identical siblings. The conditioning regimen included TBI and all grafts were partially depleted of T cells. Changes in quality of life (QOL), reproduction
Designing prospective cohort studies for assessing reproductive and developmental toxicity during sensitive windows of human reproduction and development--the LIFE Study.
Buck Louis, Germaine M; Schisterman, Enrique F; Sweeney, Anne M; Wilcosky, Timothy C; Gore-Langton, Robert E; Lynch, Courtney D; Boyd Barr, Dana; Schrader, Steven M; Kim, Sungduk; Chen, Zhen; Sundaram, Rajeshwari
The relationship between the environment and human fecundity and fertility remains virtually unstudied from a couple-based perspective in which longitudinal exposure data and biospecimens are captured across sensitive windows. In response, we completed the LIFE Study with methodology that intended to empirically evaluate a priori purported methodological challenges: implementation of population-based sampling frameworks suitable for recruiting couples planning pregnancy; obtaining environmental data across sensitive windows of reproduction and development; home-based biospecimen collection; and development of a data management system for hierarchical exposome data. We used two sampling frameworks (i.e., fish/wildlife licence registry and a direct marketing database) for 16 targeted counties with presumed environmental exposures to persistent organochlorine chemicals to recruit 501 couples planning pregnancies for prospective longitudinal follow-up while trying to conceive and throughout pregnancy. Enrolment rates varied from <1% of the targeted population (n =?424,423) to 42% of eligible couples who were successfully screened; 84% of the targeted population could not be reached, while 36% refused screening. Among enrolled couples, ? 85% completed daily journals while trying; 82% of pregnant women completed daily early pregnancy journals, and 80% completed monthly pregnancy journals. All couples provided baseline blood/urine samples; 94% of men provided one or more semen samples and 98% of women provided one or more saliva samples. Women successfully used urinary fertility monitors for identifying ovulation and home pregnancy test kits. Couples can be recruited for preconception cohorts and will comply with intensive data collection across sensitive windows. However, appropriately sized sampling frameworks are critical, given the small percentage of couples contacted found eligible and reportedly planning pregnancy at any point in time. PMID:21819423
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
3. VIEW NORTH SHOWING FIXED SPAN, COVERED SPAN, MOVEABLE TRANSITION SPAN AND PONTOON FLOATING SPAN - Lacey V. Murrow Memorial Floating Bridge, Spanning Lake Washington at I-90, Seattle, King County, WA
Fitness, reproduction and longevity among European aristocratic and rural Finnish families in the 1700s and 1800s.
Korpelainen, H
The life histories of two socio-economically different groups of humans comprising birth cohorts from the 1700s and 1800s were investigated. It was discovered that fertility selection was greater among European aristocrats and mortality selection greater among rural Finns. The life history of the rural Finns involved shorter female life spans, a considerably longer period of reproduction, higher juvenile mortality, a greater total production of offspring and slightly higher individual fitness. In a comparison of parental cohorts, it was discovered that longevity and progeny survival improved significantly from the 1700s to the 1800s. Out of the three factors investigated, longevity was found to influence reproduction and fitness more than socio-economic group or birth cohort. The reproductive efficacy and fitness of women increased along with their life span. However, reproductive success and fitness were lower among women with the longest life span (over 80 years). Among men, reproductive success improved consistently along with the increase in longevity. When birth intervals were examined, it was discovered that the sex of previous offspring did not influence the interval between births. PMID:12233775
Evolution of monogamy, paternal investment, and female life history in Peromyscus.
JaÜarevi?, Eldin; Bailey, Drew H; Crossland, Janet P; Dawson, Wallace D; Szalai, Gabor; Ellersieck, Mark R; Rosenfeld, Cheryl S; Geary, David C
The timing of reproductive development and associated trade-offs in quantity versus quality of offspring produced across the life span are well documented in a wide range of species. The relation of these aspects of maternal life history to monogamy and paternal investment in offspring is not well studied in mammals, due in part to the rarity of the latter. By using five large, captive-bred populations of Peromyscus species that range from promiscuous mating with little paternal investment (P. maniculatus bairdii) to social and genetic monogamy with substantial paternal investment (P. californicus insignis), we modeled the interaction between monogamy and female life history. Monogamy and high paternal investment were associated with smaller litter size, delayed maternal reproduction that extended over a longer reproductive life span, and larger, higher quality offspring. The results suggest monogamy and paternal investment can alter the evolution of female life-history trajectories in mammals. PMID:22545763
Multiple paternity, male reproductive success, hormonal regulation of fertility, and the evolution of life-histories
Megan Brianne Manes
The life-history strategy that an individual exhibits is shaped by trade-offs between maximizing the number of viable offspring it produces and retaining enough resources to ensure its own survival. The balance between these two aspects is strongly influenced by the environmental conditions the individual experiences in its lifetime and can be affected by the effort an individual puts into each
Japan turns pro-life: recent change in reproductive health policy and challenges by new technologies
Okamoto, Etsuji
Japan, known as a pro-choice country in terms of abortion, is currently facing the increase of ōselective abortionsö thanks to new prenatal screening. Efforts to restrict proliferation of new technology has not been successful and it is likely that Japan will turn pro-life by strictly enforcing the Maternity Protection Act (MPA), which prohibits abortions due to ōfetal causeö. PMID:24639978
Age of primiparity and implications of early reproduction on life history in female Columbian ground squirrels
P. Neuhaus; D. R. Broussard; J. O. Murie; F. S. Dobson
Summary 1. Factors leading to differences in age of primiparity and possible life-history implica- tions arising from these differences were studied in a population of Columbian ground squirrels ( Spermophilus columbianus ; Ord, 1815). We used data collected from 1992 to 2000 on two neighbouring colonies of ground squirrels in south-eastern Alberta, Canada. 2. Earlier born females were more likely
Enchytraeid Reproduction Test(PLUS): hatching, growth and full life cycle test-an optional multi-endpoint test with Enchytraeus crypticus.
Bicho, Rita C; Santos, Fßtima C F; Gonńalves, Micael F M; Soares, Amadeu M V M; Amorim, M¾nica J B
Soil ecotoxicity standard tests for invertebrates are usually limited to the assessment of endpoints like survival and reproduction. Adverse effects may occur at other developmental stages, e.g. embryo development, hatching or growth. The species Enchytraeus crypticus is a model organism in the standard soil ecotoxicology test, where survival and reproduction are assessed. In the present study we optimized the test method to include additional endpoints. The proposed test started with synchronized age organisms', and included additionally hatching success, growth, maturation status and full life cycle. This allowed for the calculation of cocoon production and population growth rate. Results indicated that Cd is embryotoxic, main effect occurs on the embryo developmental stage and maturity. Further, the full life cycle test can discriminate between pre- and post-embryo formation. The increased sensitivity and full life cycle detail level makes it potentially useful for novel materials e.g. nanomaterials where the mode of action and hence effect target is unknown. PMID:25773650
Reproductive potential predicts longevity of female Mediterranean fruitflies.
M³ller, H. G.; Carey, J. R.; Wu, D.; Liedo, P.; Vaupel, J. W.
Reproduction exacts a price in terms of decreased survival. Our analysis of the interplay between age patterns of fecundity and mortality for individual female medflies (Ceratitis capitata) revealed that individual mortality is associated with the time-dynamics of the egg-laying trajectory. In a sample of 531 medflies, we found that each individual has a characteristic rate of decline in egg laying with age. This defines an individual's rate of reproductive exhaustion. This rate was shown to predict subsequent mortality The larger the remaining reproductive potential, the lower the subsequent mortality An increased mortality risk was seen in flies for which egg production declined rapidly early on, irrespective of the level of egg production. Thus, reproductive potential and lifetime are coupled in such a way that those flies which are able to profit most from an extended life span in terms of increased egg output are indeed likely to live longer. PMID:11296855
The influence of the hot water extract from shiitake medicinal mushroom, Lentinus edodes (higher Basidiomycetes) on the food intake, life span, and age-related locomotor activity of Drosophila melanogaster.
Matjuskova, Natalya; Azena, Elena; Serstnova, Ksenija; Muiznieks, Indrikis
Shiitake medicinal mushroom, Lentinus edodes, is among the most widely cultivated edible mushrooms in the world and is a well-studied source of nutrients and biologically active compounds. We have studied the influence of the dietary supplement of the polysaccharides containing a hot water extract of the mushroom L. edodes on the fruit fly Drosophila melanogaster in terms of food intake, body weight, life span, and age-related locomotor activity. L. edodes extract, when added to the D. melanogaster feeding substrate at a 0.003-0.030% concentration (calculated for the dry weight of the polysaccharide fraction) did not influence food intake or body weight of the flies. It increased the life span and locomotor activities of male flies but was associated with early mortality and decreased locomotor activity of female flies. We conclude that the observed anti-aging effects of L. edodes extracts in the male D. melanogaster are not the result of dietary restriction. We propose that D. melanogaster is a suitable model organism for researching the molecular basis of the anti-aging effect of the shiitake mushroom extracts and sex linkage of these effects. PMID:25404225
SPAN: Astronomy and astrophysics
NASA Technical Reports Server (NTRS)
Thomas, Valerie L.; Green, James L.; Warren, Wayne H., Jr.; Lopez-Swafford, Brian
The Space Physics Analysis Network (SPAN) is a multi-mission, correlative data comparison network which links science research and data analysis computers in the U.S., Canada, and Europe. The purpose of this document is to provide Astronomy and Astrophysics scientists, currently reachable on SPAN, with basic information and contacts for access to correlative data bases, star catalogs, and other astrophysic facilities accessible over SPAN.
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
4. DETAIL VIEW FIXED SPAN INCLUDING TRUSS, MOVEABLE SPAN WHICH THE NEXT UNIT TO THE RIGHT, AND FIRST UNIT OF PONTOON FLOATING SPAN. - Lacey V. Murrow Memorial Floating Bridge, Spanning Lake Washington at I-90, Seattle, King County, WA
The structure of a thermophilic archaeal virus shows a dsDNA viral capsid type that spans all domains of life
G. Rice; L. Tang; K. Stedman; F. Roberto; J. Spuhler; E. Gillitzer; J. E. Johnson; T. Douglas; M. Young
Of the three domains of life (Eukarya, Bacteria, and Archaea), the least understood is Archaea and its associated viruses. Many Archaea are extremophiles, with species that are capable of growth at some of the highest temperatures and extremes of pH of all known organisms. Phylogenetic rRNA-encoding DNA analysis places many of the hyperthermophilic Archaea (species with an optimum growth >80░C) at the base of the universal tree of life, suggesting that thermophiles were among the first forms of life on earth. Very few viruses have been identified from Archaea as compared to Bacteria and Eukarya. We report here the structure of a hyperthermophilic virus isolated from an archaeal host found in hot springs in Yellowstone National Park. The sequence of the circular double-stranded DNA viral genome shows that it shares little similarity to other known genes in viruses or other organisms. By comparing the tertiary and quaternary structures of the coat protein of this virus with those of a bacterial and an animal virus, we find conformational relationships among all three, suggesting that some viruses may have a common ancestor that precedes the division into three domains of life >3 billion years ago.
Health-related Quality of Life in Long-term Survivors of Brain Tumors in Childhood and Adolescence: A Serial Study Spanning a Decade.
Duckworth, JoAnn; Nayiager, Trishana; Pullenayegum, Eleanor; Whitton, Anthony; Hollenberg, Robert; Horsman, John; Furlong, William; Spitzer, Rachel; Barr, Ronald D
Survivors of brain tumors in childhood experience adverse sequelae that are greater in prevalence and severity than those encountered by survivors of all other forms of cancer in early life, reflected in a burden of morbidity by instruments measuring health-related quality of life (HRQL). However, there are few studies of the change in HRQL over time in such populations. Patients who were above 5 years of age, at least 2 years from completion of therapy, and able to communicate in English were eligible for study of HRQL by the Health Utilities Index HUI2 and HUI3 at study entry, and again 5 and 10 years later. An initial cohort of 40 patients was reduced to 37 and 25 at the second and third time points, respectively, although only 1 death occurred during the study. HRQL showed a progressive decline over the decade, reaching conventional levels of clinical significance for the sizes of the changes. Median scores for HUI2 were 0.93, 0.90, and 0.88; and for HUI3 were 0.88, 0.85, and 0.77 at baseline, 5, and 10 years, respectively. The serial decline in HRQL demands further examination and an exploration of potential targets for therapeutic intervention. PMID:26018809
Spanning trees of graphs Spanning trees of simplicial complexes
Duval, Art
Spanning trees of graphs Spanning trees of simplicial complexes Color-shifted complexes Weighted spanning tree enumerators of color-shifted complexes Ghodratollah Aalipour1,2 Art Duval1 1University Ghodratollah Aalipour, Art Duval Spanning tree enumerators of color-shifted complexes #12;Spanning trees
Spanning trees of graphs Spanning trees of simplicial complexes
Duval, Art
Spanning trees of graphs Spanning trees of simplicial complexes Complete colorful complexes Weighted spanning tree enumerators of complete colorful complexes Ghodratollah Aalipour1,2 Art Duval1 1 Aalipour, Art Duval Spanning tree enumerators of complete colorful complexes #12;Spanning trees of graphs
'The brain is the organ of longevity': Introduction to G. A. Sacher's free-energy hypothesis of life-span enhancement
Justesen, D.R.
No experiment reported to date constitutes an adequate test in the sense of supplying comprehensive information on survival time, metabolic rate, food consumption and utilization, body mass, anatomical integrity (especially that of the skeletal and nervous systems), status of the immune and endocrine systems, and physiological and behavioral competence in the wake of chronic exposure to a moderately thermalizing radio field. Some reports do provide data on one or more of the important end points, usually in association with a single exposure or a limited number of brief exposures. One must distinguish between prolongation of life in senescence and enhancement of longevity based on actual retardation of the rate of aging. More, retardation of aging, if sorely taxed at the expense of quality of living, is no bargain. Some hibernators live relatively long lives, but the torpor of hibernation--a prolonged period of somnolence and greatly reduced metabolic activity--is hardly the stuff of a vibrant psychological existence.
Oosorption in response to poor food: complexity in the trade-off between reproduction and survival.
Moore, Patricia J; Attisano, Alfredo
Plasticity in reproductive physiology is one avenue by which environmental signals, such as poor quality food, can be coordinated with adaptive responses. Insects have the ability to resorb oocytes that are not oviposited. Oosorption is proposed to be an adaptive mechanism to optimize fitness in hostile environments, recouping resources that might otherwise be lost, and reinvesting them into future reproductive potential. We tested the hypothesis that oosorption is an evolved mechanism by which females can reallocate resources from current reproductive effort to survival and future reproduction, when conditions for reproduction are poor, by examining the reproductive physiology and life-history outcome under poor quality food in populations of the milkweed bug (Oncopeltus fasciatus) that have adapted to live on sunflower seed. Females fed a diet of pumpkin seeds, known to be a poor host food, had higher levels of ovarian apoptosis (oosorption), lower reproductive output, but no reduction in life span under poor nutrition, as predicted under the oosorption hypothesis. However, the schedule of reproduction was surprising given the "wait to reproduce" assumption of oosorption as early fecundity was unaffected. PMID:22393481
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
EAST END FROM MID SPAN OF EASTERN SPAN (THREE DIFFERENT TRUSSES, EAST SOUTHEAST 110 DEGREES) - Honey Run Bridge, Spanning Butte Creek, bypassed section of Honey Run Road (originally Carr Hill Road), Paradise, Butte County, CA
Life-history traits of invasive fish in small Mediterranean streams
Anna Vila-Gispert; Carles Alcaraz; Emili GarcĒa-Berthou
We compared the life-history traits of native and invasive fish species from Catalan streams in order to identify the characters of successful invasive fish species. Most of the exotic fish species were characterized by large size, long longevity, late maturity, high fecundity, few spawnings per year, and short reproductive span, whereas Iberian native species exhibited predominantly the opposite suite of
Life history consequences of overexploitation to population recovery in Northwest Atlantic cod
Hutchings, Jeffrey A.
history model. Earlier maturity more than doubles the probability of negative population growth every at maturity, changes most parsimoniously explained as genetic responses to fishing. Increased survival costs of reproduction associated with earlier maturity, resulting in higher natural mortality and shorter life span
Reproductive Biology of Baboons
Erika K. Honorķ; Suzette D. Tardif
\\u000a Reproduction in baboons has been well studied in both wild and captive populations. Much information is available regarding\\u000a life history, social behavior, anatomy, and reproductive physiology of male and female baboons. The greatest utilization of\\u000a the baboon as a biomedical model for human reproduction has involved captive females, generally colony-reared, in the study\\u000a of pregnancy. However, it has been argued
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
5. VIEW OF SPAN ADJOINING SPAN TO THE NORTH OF THE VERTICAL LIFT SPAN (IN THE DISTANCE IS THE RECENTLY COMPLETED NEW STATE ROUTE 51 BRIDGE CROSSING THE ILLINOIS RIVER). - Shippingsport Bridge, Spanning Illinois River at State Route 51, La Salle, La Salle County, IL
Spanning trees of graphs Spanning trees of simplicial complexes
Duval, Art
Spanning trees of graphs Spanning trees of simplicial complexes Color-shifted complexes Weighted spanning tree enumerators of color-shifted complexes Ghodratollah Aalipour1,2 Art Duval1 1University in St. Louis October 20, 2013 Ghodratollah Aalipour, Art Duval Spanning tree enumerators of color
Spanning trees of graphs Spanning trees of simplicial complexes
Duval, Art
Spanning trees of graphs Spanning trees of simplicial complexes Critical group of graphs Critical group of simplicial complexes Spanning trees and the critical group of simplicial complexes Art Duval1 Mathematics Colloquium New Mexico State University October 20, 2011 Duval, Klivans, Martin Spanning trees
Spanning trees of graphs Spanning trees of simplicial complexes
Duval, Art
Spanning trees of graphs Spanning trees of simplicial complexes Critical group of graphs Critical group of simplicial complexes Spanning trees and the critical group of simplicial complexes Art Duval1 of Kansas Discrete CATS seminar University of Kentucky March 30, 2011 Duval, Klivans, Martin Spanning trees
Spanning trees of graphs Spanning trees of simplicial complexes
Duval, Art
Spanning trees of graphs Spanning trees of simplicial complexes Critical group of graphs Critical group of simplicial complexes Spanning trees and the critical group of simplicial complexes Art Duval1 of Kansas Mathematics Seminar Reed College April 28, 2011 Duval, Klivans, Martin Spanning trees
Spanning trees of graphs Spanning trees of simplicial complexes
Duval, Art
Spanning trees of graphs Spanning trees of simplicial complexes Complete colorful complexes Weighted spanning tree enumerators of complete colorful complexes Ghodratollah Aalipour1,2 Art Duval1 1 April 21, 2013 Ghodratollah Aalipour, Art Duval Spanning tree enumerators of complete colorful complexes
Spanning trees of graphs Spanning trees of simplicial complexes
Duval, Art
Spanning trees of graphs Spanning trees of simplicial complexes Complete colorful complexes Weighted spanning tree enumerators of complete colorful complexes Ghodratollah Aalipour1,2 Art Duval1 1 of Mississippi March 2, 2013 Ghodratollah Aalipour, Art Duval Spanning tree enumerators of complete colorful
Parental investment, late reproduction, and increased reserve capacity are associated with longevity in humans.
Larke, Amiee; Crews, Douglas E
Throughout the living world trade-offs between reproductive success and longevity have been observed. In general, two extremes of life history patterning are reported, r- and K-selected species. The latter tend toward larger body sizes, few offspring from any one pregnancy, few offspring over the female reproductive span, longer life spans, and greater parental investment (PI: all efforts and expenses associated with the production, gestation, post-natal care, feeding, and protection of young) (e.g., whales, elephants, hominids). r-selected species tend toward smaller body size, multiple births/litters per pregnancy, female production of many gametes and offspring over the life span, and low levels of PI (e.g., most plants, insects, mice). These differences have significant influences on physiological variation among human populations. Across human samples, reproductive success (RS: the number of offspring successfully birthed and reared to reproductive age) has been reported to vary positively, negatively, and not at all with longevity of women. This complexity may be in part due to the fact that both early-life and late-life fecundity are associated with longevity in women, while total parity seems a poor gauge of female longevity in humankind. Large variations in associations of RS with longevity in women suggest that multiple factors may confound this association. One confounding factor is that among women, RS is largely determined not by fecundity, but by the quality of PI available to offspring. Among modern humans, PI is more complex, longer lasting (both relatively and absolutely), and extensive than for any other mammal. This suggests that modern human life history is a reflection of the co-evolution of longevity and extensive PI as part of our species' biocultural evolution. The need for long-term PI has greatly shaped human physiological variation and patterns of longevity. PMID:16617217
An empirical test of evolutionary theories for reproductive senescence and reproductive effort in the garter snake Thamnophis elegans
Amanda M. Sparkman; Stevan J. Arnold; Anne M. Bronikowski
Evolutionary theory predicts that differential reproductive effort and rate of reproductive senescence will evolve under different rates of external mortality. We examine the evolutionary divergence of age-specific reproduction in two life-history ecotypes of the western terrestrial garter snake, Thamnophis elegans. We test for the signature of reproductive senescence (decreasing fecundity with age) and increasing reproductive effort with age (increasing reproductive
Phenotypic plasticity in reproductive traits: importance in the life history of Helix aspersa (Mollusca: Helicidae) in a recently colonized habitat
Reproductive traits of the land snail Helix aspersa Muller were investigated under artificial conditions from two samples, one collected from a population exposed to unpredictable human pressures in its natural environment, i.e. a recently created polders area with intensive agriculture, and the other from a snail farm in which animals were reared under constant conditions defined as 'optimal' for growth
A study of reproduction and other life cycle phenomena in planktonic protists using an acridine orange fluorescence technique
D. W. Coats; J. F. Heinbokel
The percentage of dividing individuals and temporal reproductive patterns were determined for natural populations of several planktonic protists including five species of tintinnids, a dinoflagellate, and a diatom. To obtain these data, a method was used in which the nuclei of planktonic ciliates and phytoplankters can be fluorescently stained with acridine orange at the time of collection and fixation. The
Learning To Learn across the Life Span.
ERIC Educational Resources Information Center
Smith, Robert M.; And Others
Ways to help learners of all ages to independently search out and use existing knowledge and new information to solve problems and acquire new skills is examined through 15 papers by leading experts in learning-to-learn theory and application. Papers have the following titles and authors: "The Promise of Learning to Learn" (Robert M. Smith); "Howģ
Autobiographical Memory from a Life Span Perspective
ERIC Educational Resources Information Center
Schroots, Johannes J. F.; van Dijkum, Cor; Assink, Marian H. J.
This comparative study (i.e., three age groups, three measures) explores the distribution of retrospective and prospective autobiographical memory data across the lifespan, in particular the bump pattern of disproportionally higher recall of memories from the ages 10 to 30, as generally observed in older age groups, in conjunction with theģ
Angiotensin receptors as determinants of life span
Paola Cassis; Sara Conti; Giuseppe Remuzzi; Ariela Benigni
Angiotensin II (Ang II), the central product of renin-angiotensin system, has a role in the etiology of hypertension and in\\u000a pathophysiology of cardiac and renal diseases in humans. Other functions of Ang II include effects on immune response, inflammation,\\u000a cell growth and proliferation, which are largely mediated by Ang II type 1 receptor (AT1). Several experimental studies have demonstrated that
More Whole Grains May Boost Life Span
... longer. In the study, researchers looked at whole fiber -- the whole seed of grain that's used in ... researchers found that those who ate the most fiber were 17 percent less likely to die during ...
A report from the 2013 international symposium: the evaluation of the effects of low-dose radiation exposure in the life span study of atomic bomb survivors and other similar studies.
Grant, E J; Ozasa, K; Ban, N; de Gonzßlez, A Berrington; Cologne, J; Cullings, H M; Doi, K; Furukawa, K; Imaoka, T; Kodama, K; Nakamura, N; Niwa, O; Preston, D L; Rajaraman, P; Sadakane, A; Saigusa, S; Sakata, R; Sobue, T; Sugiyama, H; Ullrich, R; Wakeford, R; Yasumura, S; Milder, C M; Shore, R E
The RERF International Low-Dose Symposium was held on 5-6 December 2013 at the RERF campus in Hiroshima, Japan, to discuss the issues facing the Life Span Study (LSS) and other low-dose studies. Topics included the current status of low-dose risk detection, strategies for low-dose epidemiological and statistical research, methods to improve communication between epidemiologists and biologists, and the current status of radiological studies and tools. Key points made by the participants included the necessity of pooling materials over multiple studies to gain greater insight where data from single studies are insufficient; generating models that reflect epidemiological, statistical, and biological principles simultaneously; understanding confounders and effect modifiers in the current data; and taking into consideration less studied factors such as the impact of dose rate. It is the hope of all participants that this symposium be used as a trigger for further studies, especially those using pooled data, in order to reach a greater understanding of the health effects of low-dose radiation. PMID:25811153
Characteristics of an infinite life span diploid human fibroblast cell strain and a near-diploid strain arising from a clone of cells expressing a transfected v-myc oncogene
Morgan, T.L.; Dajun Yang; Fry, D.G.; Hurlin, P.J.; Kohler, S.K.; Maher, V.M.; McCormick, J.J. (Michigan State Univ., East Lansing (United States))
Diploid human fibroblasts were transfected with a plasmid carrying a v-myc oncogene linked to the neo gene or with a vector control carrying a neo gene. Drug-resistant clones were isolated and subcultured as needed. All populations went into crisis and eventually senesced. But while they were senescing, viable-appearing clones were noted among the progeny of a transfected population that expressed the v-myc oncogene. After several months, these cells began replicating more rapidly. Karyotype analysis indicated that they were clonally derived since all of them had 45 chromosomes, including 2 marker chromosomes. This cell strain was designated MSU-1.1. Similar analysis showed that cells from an earlier passage were diploid. These cells were designated MSU-1.0. The expression of v-myc is probably required for acquisition of an infinite life span, since this phenotype did not develop in populations not expressing this oncogene. However, expression of v-myc is clearly not sufficient, since all of the progeny of the clone that gave rise to the MSU-1.0 cells expressed this oncogene, but the vast majority of them senesced.
NSDL National Science Digital Library
The C-SPAN in the classroom website is geared toward teachers of political science - or specifically U.S. Government. The site is split into six segments: Principles of Government, the Constitution, Political Participation and each of the three branches of government. Each of these sections features video clips, and questions for class discussion. Free site membership is available, but not required to use the site. Some additional content and services are available with membership.
An emerging interface between life science and nanotechnology: present status and prospects of reproductive healthcare aided by nano-biotechnology
Jha, Rakhi K.; Jha, Pradeep K.; Chaudhury, Koel; Rana, Suresh V.S.; Guha, Sujoy K.
Among the various applications of nano-biotechnology, healthcare is considered one of the most significant domains. For that possibility to synthesize various kind of nanoparticles (NPs) and the ever-increasing ability to control their size as well as structure, to improve surface characteristics and binding NPs with other desired curing agents has played an important role. In this paper, a brief sketch of various kinds of nanomaterials and their biomedical applications is given. Despite claims of bio-nanotechnology about to touch all areas of medical science, information pertaining to the role of nanotechnology for the betterment of reproductive healthcare is indeed limited. Therefore, the various achievements of nano-biotechnology for healthcare in general have been illustrated while giving special insight into the role of nano-biotechnology for the future of reproductive healthcare betterment as well as current achievements of nanoscience and nanotechnology in this arena. PMID:24600516
Growth and reproduction of the mosquitofish, Gambusia affinis , in relation to temperature and ration level: consequences for life history
Bruce Vondracek; Wayne A. Wurtsbaugh; Joseph J. Cech
SynopsisĀĀThe allocation of energy to growth and reproduction, in relation to temperature and food availability, was investigated in\\u000a laboratory experiments with the mosquitofish,Gambusia affinis. At constant temperature of 20, 25 and 30░C and ad libitum feeding, specific growth rates increased with increasing temperature\\u000a at 1.7, 3.1 and 3.4% dry mass day?1, respectively. Growth rates in a cycling temperature regime (20¢30░C,
Estrogenic environmental endocrine-disrupting chemical effects on reproductive neuroendocrine function and dysfunction across the life cycle
Sarah M. Dickerson; Andrea C. Gore
Endocrine disrupting chemicals (EDCs) are natural or synthetic compounds that interfere with the normal function of an organismÆs\\u000a endocrine system. Many EDCs are resistant to biodegradation, due to their structural stability, and persist in the environment.\\u000a The focus of this review is on natural and artificial EDCs that act through estrogenic mechanisms to affect reproductive neuroendocrine\\u000a systems. This endocrine axis
16. Overall view of the swing span (Span G) turning ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
16. Overall view of the swing span (Span G) turning drum, showing rollers and drive chains; looking W. (Ceronie) - Rock Island Arsenal, Rock Island Bridge, Fort Armstrong Avenue, Rock Island, Rock Island County, IL
13. General view of the stringer system, swing span (Span ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
13. General view of the stringer system, swing span (Span G), showing also the floor beams and anti-sway bracing; looking NNW. (Harms) - Rock Island Arsenal, Rock Island Bridge, Fort Armstrong Avenue, Rock Island, Rock Island County, IL
Caloric restriction: Impact upon pituitary function and reproduction
Martin, Bronwen; Golden, Erin; Carlson, Olga D.; Egan, Josephine M.; Mattson, Mark P.; Maudsley, Stuart
Reduced energy intake, or caloric restriction (CR), is known to extend life span and to retard age-related health decline in a number of different species, including worms, flies, fish, mice and rats. CR has been shown to reduce oxidative stress, improve insulin sensitivity, and alter neuroendocrine responses and central nervous system (CNS) function in animals. CR has particularly profound and complex actions upon reproductive health. At the reductionist level the most crucial physiological function of any organism is its capacity to reproduce. For a successful species to thrive, the balance between available energy (food) and the energy expenditure required for reproduction must be tightly linked. An ability to coordinate energy balance and fecundity involves complex interactions of hormones from both the periphery and the CNS and primarily centers upon the master endocrine gland, the anterior pituitary. In this review article we review the effects of CR on pituitary gonadotrope function and on the male and female reproductive axes. A better understanding of how dietary energy intake affects reproductive axis function and endocrine pulsatility could provide novel strategies for the prevention and management of reproductive dysfunction and its associated comorbidities. PMID:18329344
Changes in reproductive life-history strategies in response to nest density in a shell-brooding cichlid, Telmatochromis vittatus
NASA Astrophysics Data System (ADS)
Ota, Kazutaka; Hori, Michio; Kohda, Masanori
To determine whether the appearance of a reproductively parasitic tactic varies, and how this variation affects territorial males of the Lake Tanganyika cichlid fish Telmatochromis vittatus, we examined the reproductive ecology of territorial males in Mtondwe and compared it with that of a neighboring Wonzye population, where nest density differs from that at Mtondwe. In Wonzye, with high nest density, male tactics change with their body size from a territorial to a non-territorial parasitic tactic called piracy in which they conquer several nests defended by territorial males and take over the nests while females are spawning. These "pirate" males could decrease the costs incurred by travelling among nests by exclusively targeting aggregations of nests in close proximity while avoiding separate nests. Territorial males in Wonzye sacrifice the potential higher attractiveness offered by large nests and instead compete for nests farther from neighbors on which pirates less frequently intrude. In contrast, the Mtondwe population had lower nest density and piracy was absent. Given that the success of piracy depends on the close proximity of nests, nest density is likely responsible for the observed variation in the occurrence of piracy between the two populations. Furthermore, in Mtondwe, territorial males competed for larger nests and were smaller than the territorial males in Wonzye. Thus, this lower nest density may free territorial males from the selection pressures for increased size caused by both defense against nest piracy and the need to develop into pirates as they grow.
Changes in reproductive life-history strategies in response to nest density in a shell-brooding cichlid, Telmatochromis vittatus.
Ota, Kazutaka; Hori, Michio; Kohda, Masanori
To determine whether the appearance of a reproductively parasitic tactic varies, and how this variation affects territorial males of the Lake Tanganyika cichlid fish Telmatochromis vittatus, we examined the reproductive ecology of territorial males in Mtondwe and compared it with that of a neighboring Wonzye population, where nest density differs from that at Mtondwe. In Wonzye, with high nest density, male tactics change with their body size from a territorial to a non-territorial parasitic tactic called piracy in which they conquer several nests defended by territorial males and take over the nests while females are spawning. These "pirate" males could decrease the costs incurred by travelling among nests by exclusively targeting aggregations of nests in close proximity while avoiding separate nests. Territorial males in Wonzye sacrifice the potential higher attractiveness offered by large nests and instead compete for nests farther from neighbors on which pirates less frequently intrude. In contrast, the Mtondwe population had lower nest density and piracy was absent. Given that the success of piracy depends on the close proximity of nests, nest density is likely responsible for the observed variation in the occurrence of piracy between the two populations. Furthermore, in Mtondwe, territorial males competed for larger nests and were smaller than the territorial males in Wonzye. Thus, this lower nest density may free territorial males from the selection pressures for increased size caused by both defense against nest piracy and the need to develop into pirates as they grow. PMID:22089034
A Perspective on the Importance of Reproductive Mode in Astrobiology
Karine Van Doninck; Isa Sch÷n; Koen Martens
Reproduction is a vital characteristic of life, and sex is the most common reproductive mode in the eukaryotic world. Sex and reproduction are not necessarily linked mechanisms: Sexuality without reproduction exists, while several forms of asexual reproduction are known. The occurrence of sexuality itself is paradoxical, as it is very costly in evolutionary terms. Most of the hypotheses (more than
Sentencing Juveniles to Life in Prison: The Reproduction of Juvenile Justice for Young Adolescents Charged with Murder
ERIC Educational Resources Information Center
Singer, Simon I.
In "Roper v. Simmons," the U.S. Supreme Court determined that the sentencing of juveniles to death violated the constitutional amendment against cruel and unusual punishment. Similarly, the Court most recently decided that life without parole for non-homicide offenses is also unconstitutional ("Graham v. Florida," 2010). Part of the reason for theģ
Life history strategies in zooplankton communities: The significance of female gonad morphology and maturation types for the reproductive biology of marine calanoid copepods
NASA Astrophysics Data System (ADS)
Niehoff, Barbara
The present review addresses the reproductive strategies of marine calanoid copepods, as affected by their physiological preconditioning, and aims to enhance understanding of their adaptations to specific environmental conditions. Knowledge about oocyte development and internal gonad structure, especially in relation to feeding conditions, is essential for a complete understanding of the reproductive strategies of the copepods. Therefore, the foci of the review are to identify general patterns in oocyte and gonad development in calanoid copepod species from marine ecosystems worldwide and to elucidate the significance of gonad structures for reproductive strategies. Oogenesis is similar in all copepod species. During maturation, the morphology of the oocytes changes distinctly and, according to oocyte size and appearance of ooplasm and nucleus, five oocyte developmental stages are distinguished. In contrast, the gonad structure and its changes during the spawning cycle differ considerably among species, and these differences are related to specific reproductive traits. Four gonad morphology types can be distinguished: the Calanus-type, found in species from all over the world with distinctly different life history traits, is apparently most common in calanoid copepods. In this gonad type, most oocyte developmental stages are present simultaneously, and usually many oocytes mature synchronously, all of which are released in one clutch. The gonad structure allows frequent spawning and large clutches, hence, high egg production rates. This may be a preconditioning for exploiting seasonally high food supply. However, the Calanus-type was also found in species producing eggs at lower rates. In the diverticula of Pseudocalanus-type gonads, only two oocyte developmental stages are present and usually fewer oocytes mature synchronously. Accordingly, the egg production rate is generally lower as compared to the Calanus-type, and apparently only this gonad-type is structurally suitable for ovigerity. Species with Pseudocalanus-type gonads are present from polar seas to the tropics, some of them being key species. The Acartia-type was scarce, found in only one species, Acartia clausi. Here all oocyte developmental stages are present, including intermediate stages, but only a few oocytes mature synchronously and are released together. High spawning frequency compensates for the small clutches, and hence egg production rate may be as high as in Calanus-type gonads. In the Aetidius-type gonad, the total number of oocytes in the diverticula is low as is the number of oocytes maturing synchronously. Less is known about the reproductive biology of species with Aetidius-type gonads; however, their distribution and feeding patterns suggest that this type is common in species inhabiting environments of low food availability. The differences in gonad structures also lead to differences in the egg size:female size ratio, as the space available for each mature oocyte depends on the total number of oocytes. Independent from gonad-type, the eggs are relatively large in species in which the gonads contain only few oocytes, whereas small eggs are produced by species with gonads filled with many oocytes. Since all species carrying their eggs in external sacs until hatching (ovigerous species) have Pseudocalanus-type gonads, the scatter in their egg size:female size ratio is low. The broadcast spawning species are of all gonad-types, and consequently the scatter among them is high. A major factor affecting the timing and magnitude of spawning of calanoid copepods is the energy supply for gonad development. Therefore, part of the review elucidates the role of internal and external resources in fuelling egg production. In many species, freshly assimilated food is transferred into egg material within a short period of time, and clutch size and spawning frequency are the two parameters that allow adjustment of egg production to food availability and temperature. However, internal body reserves may also fuel oocyte development. The extent to which oogene
Development on drought-stressed host plants affects life history, flight morphology and reproductive output relative to landscape structure
Gibbs, Melanie; Van Dyck, Hans; Breuker, Casper J
With global climate change, rainfall is becoming more variable. Predicting the responses of species to changing rainfall levels is difficult because, for example in herbivorous species, these effects may be mediated indirectly through changes in host plant quality. Furthermore, species responses may result from a simultaneous interaction between rainfall levels and other environmental variables such as anthropogenic land use or habitat quality. In this eco-evolutionary study, we examined how male and female Pararge aegeria (L.) from woodland and agricultural landscape populations were affected by the development on drought-stressed host plants. Compared with individuals from woodland landscapes, when reared on drought-stressed plants agricultural individuals had longer development times, reduced survival rates and lower adult body masses. Across both landscape types, growth on drought-stressed plants resulted in males and females with low forewing aspect ratios and in females with lower wing loading and reduced fecundity. Development on drought-stressed plants also had a landscape-specific effect on reproductive output; agricultural females laid eggs that had a significantly lower hatching success. Overall, our results highlight several potential mechanisms by which low water availability, via changes in host plant quality, may differentially influence P. aegeria populations relative to landscape structure. PMID:25568030
Independent chemical regulation of health and senescent spans in Drosophila
Arking, Robert
Curcumin feeding of Drosophila larvae or young adults inhibits TOR and other known longevity genes and induces an extended health span in a normal-lived Ra strain adult. Combining larval curcumin feeding with an adult dietary restriction (DR) diet does not yield an additive effect. The age-specific mortality rate is decreased and is comparable with that of genetically selected long-lived La animals. Feeding Ra adults with the drug their whole life, or only during the senescent span, results in a weak negative effect on median longevity with no increase in maximum lifespan. The La strain shows no response to this DR mimetic. Thus, curcumin acts in a life stage-specific manner to extend the health span. Histone deacetylase inhibitors decrease the longevity of Ra animals if administered over the health span only or over the entire adult lifespan, but these inhibitors increase longevity when administered in the transition or senescent spans. Their major effect is a reduction in the mortality rate of older flies, raising the possibility of reducing frailty in older organisms. Their life stage-specific effects are complementary to that of curcumin. Use of stage-specific drugs may enable targeted increases in health or senescent spans, and thus selectively increase the quality of life.
Culling intervals and culling risks in four stages of the reproductive life of first service and reserviced female pigs in commercial herds.
Sasaki, Y; Koketsu, Y
The objectives of this study were to measure culling intervals and culling risks in the four stages of the reproductive life of female pigs and to compare culling intervals between the number of services and between herd groups, based on herd productivity. We also compared survival patterns of females pigs between these herd groups. Our data set included lifetime records of 52,792 females born between 2001 and 2004 in 101 commercial herds. Two herd groups were selected on the basis of the upper 25th percentile of pigs weaned per mated female per 5 yr between 2002 and 2006, namely the high-performing herds, and ordinary herds. Culled females were also allocated into four groups based on the stages of their reproductive life when culled: unmated gilts, mated gilts, unmated sows, and mated sows. Culling intervals in unmated gilts and mated gilts were defined as the number of days from birth to culling and from first mating to culling, respectively. Culling intervals in unmated sows and mated sows were the number of days from weaning to culling. The number of services was categorized into two groups: first service and reservice groups. Multilevel linear mixed-effects models and survival analysis were performed. Culling intervals (+/-SEM) in unmated gilts, mated gilts, unmated sows, and mated sows were 302.9+/-1.16, 98.4+/-0.92, 14.3+/-0.12, and 89.6+/-0.42 d, respectively. Culling risks in the four groups were 5.6%, 7.1%, 58.0%, and 29.3%, respectively. In unmated gilts, mated gilts, and mated sows, the culling intervals in the high-performing herds were 43.0, 18.9, and 16.0 d shorter than those in ordinary herds, respectively (P<0.05), but no difference was found between the herd groups for the culling interval of unmated sows. For mated sows in the reservice group, culling intervals of high-performing herds were >or=13.7 d shorter than those of the ordinary herds (P<0.05), but for mated sows in the first service group, there was no difference in the culling interval between the herd groups. The culling hazard from 8 wk postweaning for mated sows in high-performing herds increased more rapidly than that in ordinary herds. In conclusion, to reduce culling intervals and improve herd productivity, we recommend implementing a strict culling policy for mated gilts and mated sows, especially reserviced females. PMID:20006377
... and female reproductive systems play a role in pregnancy. Problems with these systems can affect fertility and ... a reproductive hazard can cause different effects during pregnancy, depending on when she is exposed. During the ...
Life-history traits of invasive fish in small Mediterranean streams
Anna Vila-Gispert; Carles Alcaraz; Emili GarcĒa-Berthou
We compared the life-history traits of native and invasive fish species from Catalan streams in order to identify the characters\\u000a of successful invasive fish species. Most of the exotic fish species were characterized by large size, long longevity, late\\u000a maturity, high fecundity, few spawnings per year, and short reproductive span, whereas Iberian native species exhibited predominantly\\u000a the opposite suite of
Childhood Abuse is Associated with Adiposity in Mid-life Women: Possible Pathways through Trait Anger and Reproductive Hormones
Midei, Aimee J.; Matthews, Karen A.; Bromberger, Joyce T.
Objective To examine the association between childhood abuse/neglect and central adiposity and obesity in a sample of 311 women (106 Black, 205 White) from the Pittsburgh site of the Study of Women's Health Across the Nation (SWAN). Methods SWAN included a baseline measurement of women in midlife (mean age = 45.7) and 8 follow-up visits during which waist circumference (WC) and body mass index (BMI) were measured. The Childhood Trauma Questionnaire retrospectively assessed emotional, physical, and sexual abuse and emotional and physical neglect in childhood. Results ANCOVA analyses showed that women with a history of any abuse/neglect, and specifically physical and sexual abuse, had significantly higher WC and BMI at baseline than women with no abuse history. A significant interaction between abuse and BMI showed that among women with BMI < 30, any abuse/neglect and certain subtypes of abuse predicted greater increases in WC over time. Additional analyses showed that Trait Anger scores and sex hormone-binding globulin (SHBG) attenuated cross-sectional relationships between abuse/neglect and WC and BMI. Conclusion This study suggests that abused/neglected women appear to have greater anger and lower levels of SHBG, which are associated with adiposity in mid-life. PMID:20064904
ERIC Educational Resources Information Center
Turkington, B. A.
This autoinstructional lesson deals with the study of the human body with emphasis on the life process of reproduction. It is a learning activity included in high school biology or health education classes. The behavioral objectives are listed and the equipment and materials needed to help the student gain these objectives are also included in theģ
Noncancer risk assessment: reproductive toxicology.
Schwetz, B A
In summary, the concerns that environmental and other agents are causing adverse effects on reproductive function in humans are real, although the risk is not necessarily well characterized. The range of concerns for the types of effect that agents might have on reproduction span the full range of reproductive events. There is a fairly high background of reproductive disease in humans which decreases the sensitivity for identifying agents that have a subtle, but adverse, effect on reproductive performance of humans. Because our animal studies identify a large number of agents that cause some adverse reproductive effect at the dose levels tested, the concern is raised about the oversensitivity of animal models for predicting adverse effects in humans. Until we better understand the biology underlying the reproductive process of humans and animals, it will be difficult to make animal studies more specific in their predictiveness. Continued research to better understand the biology of reproduction in humans and animals should help to identify the types of data generated in animals that are most predictive of an adverse effect in humans. PMID:8744590
Life table of Paederus fuscipes (Coleoptera: Staphylinidae).
Bong, Lee-Jin; Neoh, Kok-Boon; Jaal, Zairi; Lee, Chow-Yang
The life history characteristics of the rove beetle Paederus fuscipes Curtis were studied under laboratory conditions using three field strains from Malaysia: Desa Wawasan (DW), Sri Pinang (SP), and Ampang Jajar (AJ). The total development time of immature stages differed significantly among the three strains, especially between DW (17.43 +/- 0.16 d), SP (18.60 +/- 0.19 d), and AJ (18.68 +/- 0.22 d). Adult females and males from DW also exhibited a shorter life span, although the difference among strains was not significant. In terms of fecundity, the numbers of eggs laid per female for DW, SP, and AJ were 121.28 +/- 15.98, 127.30 +/- 18.01, and 147.45 +/- 17.12, respectively. Additionally, because of the shorter life span in DW strain, two apparent peaks in age-stage specific fecundity were detected. The beetles compensated for their shorter life span by increasing their reproductive activity to sustain the progeny in the population. The intrinsic rates of increase (r) of P. fuscipes from DW, SP, and AJ were 0.0773 +/- 0.0046 d(-1), 0.0788 +/- 0.0051 d(-1), and 0.0873 +/- 0.0054 d(-1), respectively; and the net reproduction rates (R0) were 40.09 +/- 7.39 offspring, 45.29 +/- 8.74 offspring, and 42.34 +/- 8.25 offspring, respectively. The mean generation time of P. fuscipes from AJ was 43.08 +/- 1.07 d, which was significantly higher than that from DW (47.95 +/- 1.36 d) and SP (48.57 +/- 1.43 d). The total immature development time of P. fuscipes in this study was shorter than values reported in previous studies. PMID:22679850
Reproductive ecology of female chimpanzees.
Thompson, Melissa Emery
An important adaptive problem for mammals in general, and primates in particular, is how females can manage the high costs of reproduction in the face of fluctuating energetic supplies. For many species, the best solution is to breed seasonally such that high costs are temporally coincident with predictable periods of resource abundance. This is an unreliable strategy for some primates, such as chimpanzees (Pan troglodytes), for which large body size forces an increase in dietary complexity and prolonged reproductive efforts. Here, I review data on reproductive function in chimpanzees, a species that demonstrates a risk-averse reproductive strategy wherein reproductive investment is allocated in accordance with maternal condition. Life history parameters for chimpanzees indicate that most females produce very few surviving offspring. However, comparisons between captive and wild populations and within wild populations illustrate that variation in resource access leads to highly variable reproductive success. Focused hormonal studies have demonstrated these effects at a proximate level, with energetic influences on female dispersal, receptivity, cycle quality, conception success, and lactational amenorrhea. Downstream of these effects, female reproductive function affects sexual attractiveness, and by virtue of males' own optimal reproductive strategies, can lead to coercive aggression and decreased foraging efficiency. Because of their extreme reproductive costs, female chimpanzees utilize a highly conservative reproductive strategy, one that minimizes the costs of ecological variation but makes them vulnerable to sexual conflict and costs of sociality. PMID:23015287
Reproductive governance in Latin America.
Morgan, Lynn M; Roberts, Elizabeth F S
This paper develops the concept of reproductive governance as an analytic tool for tracing the shifting political rationalities of population and reproduction. As advanced here, the concept of reproductive governance refers to the mechanisms through which different historical configurations of actors - such as state, religious, and international financial institutions, NGOs, and social movements - use legislative controls, economic inducements, moral injunctions, direct coercion, and ethical incitements to produce, monitor, and control reproductive behaviours and population practices. Examples are drawn from Latin America, where reproductive governance is undergoing a dramatic transformation as public policy conversations are coalescing around new moral regimes and rights-based actors through debates about abortion, emergency contraception, sterilisation, migration, and assisted reproductive technologies. Reproductive discourses are increasingly framed through morality and contestations over 'rights', where rights-bearing citizens are pitted against each other in claiming reproductive, sexual, indigenous, and natural rights, as well as the 'right to life' of the unborn. The concept of reproductive governance can be applied to other settings in order to understand shifting political rationalities within the domain of reproduction. PMID:22889430
DEP and AFO Regulate Reproductive Habit in Rice
Kejian Wang; Ding Tang; Lilan Hong; Wenying Xu; Jian Huang; Ming Li; Minghong Gu; Yongbiao Xue; Zhukuan Cheng
Sexual reproduction is essential for the life cycle of most angiosperms. However, pseudovivipary is an important reproductive strategy in some grasses. In this mode of reproduction, asexual propagules are produced in place of sexual reproductive structures. However, the molecular mechanism of pseudovivipary still remains a mystery. In this work, we found three naturally occurring mutants in rice, namely, phoenix (pho),
Reproductive investment and somatic growth rates in longear sunfish
Martin J. Jennings; David P. Philipp
Synopsis Allocation of energy to current reproduction at the expense of other functions, such as growth, can limit future reproductive potential. This cost of reproduction is a central concept of life history theory but has been difficult to verify in comparative field studies. Three levels of comparison of growth rates and reproductive investments were evaluated within and among populations of
Effects of reproduction on immuno-suppression and oxidative damage, and hence support or otherwise for their roles as mechanisms underpinning life history trade-offs, are tissue and assay dependent.
Yang, Deng-Bao; Xu, Yan-Chao; Wang, De-Hua; Speakman, John R
Life history parameters appear to be traded off against each other, but the physiological mechanisms involved remain unclear. One hypothesis is that potentially energetically costly processes such as immune function and protection from oxidative stress may be compromised during reproductive attempts because of selective resource allocation. Lower temperatures also impose energy costs, and hence allocation decisions might be more pronounced when animals are forced to reproduce in the cold. Here, we experimentally tested whether reproduction at different ambient temperatures was associated with elevated oxidative stress and suppressed immune function in Mongolian gerbils (Meriones unguiculatus). Using a variety of different markers for both immune function and oxidative stress, we found that some measures of immune function (serum bactericidal capacity and size of the thymus) were significantly suppressed, while some measures of oxidative protection [serum superoxide dismutase (SOD) activity and glutathione peroxidase (GPx) activity] were also reduced, and a marker of oxidative damage (protein carbonyls in serum) was increased in lactating compared with non-reproductive gerbils. These changes were in line with the selective resource allocation predictions. However, the phytohaemagglutinin response and serum total immunoglobulin (IgG) were not suppressed, and other markers of oxidative damage [malondialdehyde (MDA) (TBARS) and protein carbonyls in the liver] were actually lower in lactating compared with non-reproductive gerbils, consistent with increased levels of SOD activity and total antioxidant capacity in the liver. These latter changes were opposite of the expectations based on resource allocation. Furthermore, other measures of protection (GPx levels in the liver and protein thiols in both serum and liver) and damage [MDA (TBARS) in serum] were unrelated to reproductive status. Ambient temperature differences did not impact on these patterns. Collectively, our results indicated that the inferred effects of reproduction on immunosuppression and oxidative damage, and hence support or otherwise for particular physiological mechanisms that underpin life history trade-offs, are critically dependent on the exact markers and tissues used. This may be because during reproduction individuals selectively allocate protection to some key tissues, but sacrifice protection of others. PMID:23997195
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This Topic in Depth takes a look at organizations and educational websites concerned with reproduction in humans and other animals. The Society for the Study of Reproduction (SSR) "is an association of scientists and physicians interested in research in reproduction. Some members are engaged in basic or applied research, while others perform clinical practice." The SSR website (1) contains downloadable copies of the SSR Newsletter; position statements; and information about meetings, awards, and the organization. The Society for Reproduction and Fertility (SRF) "is open to scientists and students worldwide, who work on any aspect of reproductive biology or fertility in man and animals." The SRF website (2) contains sections regarding News, Events, Jobs, Honours, and Grants. SRF makes downloadable copies of its newsletter available as well. The primary aim of the European Society of Human Reproduction & Embryology (ESHRE) "is to promote interest in, and understanding of, reproductive biology and medicine. It does this through facilitating research and subsequent dissemination of research findings in human reproduction and embryology to the general public, scientists, clinicians and patient associations; it also works to inform politicians and policy makers throughout Europe." The ESHRE site (3) contains information about activities, membership, publications, special interest groups, and jobs. The primary function of the Centre for Reproductive Biology in Uppsala (CRU) "is to increase the knowledge about reproduction in animals and humans by applying a more comprehensive view on reproductive biology." CRU is composed of scientists from both Uppsala University and the Swedish University of Agricultural Science. The CRU site (4) contains information about a number of publications, and contact information for CRU members. The Population Council is a nonprofit "organization that conducts biomedical, social science, and public health research." The "Council's reproductive biology and immunology program undertakes fundamental research in the reproductive sciences and immunological processes related to sexually transmitted infections, particularly HIV." This website (5) provides information about different aspects of the research program including Germ Cell Dynamics, Sperm Maturation, and Physiology of Sertoli Cells. From Dr. Michael Gregory of Clinton Community College, the next site (6) is a concise overview of animal reproduction which addresses important aspects of sexual reproduction, and male and female reproductive systems. The final site (7) contains lecture notes regarding avian reproduction from Dr. Gary Ritchison's Ornithology course at Eastern Kentucky University. The lecture notes are interspersed with some especially nice images and diagrams.
VIV analysis of pipelines under complex span conditions
NASA Astrophysics Data System (ADS)
Wang, James; Steven Wang, F.; Duan, Gang; Jukes, Paul
Spans occur when a pipeline is laid on a rough undulating seabed or when upheaval buckling occurs due to constrained thermal expansion. This not only results in static and dynamic loads on the flowline at span sections, but also generates vortex induced vibration (VIV), which can lead to fatigue issues. The phenomenon, if not predicted and controlled properly, will negatively affect pipeline integrity, leading to expensive remediation and intervention work. Span analysis can be complicated by: long span lengths, a large number of spans caused by a rough seabed, and multi-span interactions. In addition, the complexity can be more onerous and challenging when soil uncertainty, concrete degradation and unknown residual lay tension are considered in the analysis. This paper describes the latest developments and a æstate-of-the-artÆ finite element analysis program that has been developed to simulate the span response of a flowline under complex boundary and loading conditions. Both VIV and direct wave loading are captured in the analysis and the results are sequentially used for the ultimate limit state (ULS) check and fatigue life calculation.
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Asexual reproduction: Genetics and evolutionary aspects T. de Mees*, F. Prugnolle and P. Agnew
Review Asexual reproduction: Genetics and evolutionary aspects T. de Mee▀s*, F. Prugnolle and P of asexual reproduction for eukaryotic organisms and how its integration in a life cycle can influence importance of asexual organisms. Keywords. Asexual, vegetative, parthenogenesis, clonality, reproduction
Hibernation is associated with increased survival and the evolution of slow life histories among mammals
Turbill, Christopher; Bieber, Claudia; Ruf, Thomas
Survival probability is predicted to underlie the evolution of life histories along a slow¢fast continuum. Hibernation allows a diverse range of small mammals to exhibit seasonal dormancy, which might increase survival and consequently be associated with relatively slow life histories. We used phylogenetically informed GLS models to test for an effect of hibernation on seasonal and annual survival, and on key attributes of life histories among mammals. Monthly survival was in most cases higher during hibernation compared with the active season, probably because inactivity minimizes predation. Hibernators also have approximately 15 per cent higher annual survival than similar sized non-hibernating species. As predicted, we found an effect of hibernation on the relationships between life history attributes and body mass: small hibernating mammals generally have longer maximum life spans (50% greater for a 50 g species), reproduce at slower rates, mature at older ages and have longer generation times compared with similar-sized non-hibernators. In accordance with evolutionary theories, however, hibernating species do not have longer life spans than non-hibernators with similar survival rates, nor do they have lower reproductive rates than non-hibernators with similar maximum life spans. Thus, our combined results suggest that (i) hibernation is associated with high rates of overwinter and annual survival, and (ii) an increase in survival in hibernating species is linked with the coevolution of traits indicative of relatively slow life histories. PMID:21450735
Latitudinal and seasonal variation in reproductive effort of the eastern fence lizard (Sceloporus undulatus).
DU, Weiguo; Robbins, Travis R; Warner, Daniel A; Langkilde, Tracy; Shine, Richard
Geographic variation in life-history traits among populations of wide-ranging species is influenced by both spatial and temporal aspects of the environment. Rarely, however, are the effects of both aspects examined concurrently. We collected gravid female lizards (Sceloporus undulatus) from northern (Indiana), central (Mississippi) and southern (Florida) populations, spanning nearly the full latitudinal range of the species, to examine among population differences in strategies of reproductive energy allocation. Adult females from the southern population were smaller, and produced fewer and smaller eggs in their first clutches than did females from the more northern populations. Southern females were more likely to produce a second clutch, and second clutches were smaller than first clutches for females from the 2 northern populations. Together these trends eliminated population differences in overall reproductive output after accounting for body size. The trend for greater reproductive energy to be allocated to first clutches at higher latitudes, and to later clutches at lower latitudes is corroborated by published data from field studies on multiple populations. Distributing reproductive effort by producing more clutches of smaller eggs may be an adaptive response to the long season available for egg incubation and lizard activity in sub-tropical southern environments. In contrast, allocating greater resources to early reproduction may enhance maternal fitness in the relatively short activity seasons that characterize more northern sites. PMID:24148228
Reluga, Timothy C.; Medlock, Jan; Galvani, Alison
The basic reproductive number, , and the effective reproductive number, , are commonly used in mathematical epidemiology as summary statistics for the size and controllability of epidemics. However, these commonly used reproductive numbers can be misleading when applied to predict pathogen evolution because they do not incorporate the impact of the timing of events in the life-history cycle of the pathogen. To study evolution problems where the host population size is changing, measures like the ultimate proliferation rate must be used. A third measure of reproductive success, which combines properties of both the basic reproductive number and the ultimate proliferation rate, is the discounted reproductive number . The discounted reproductive number is a measure of reproductive success that is an individualÆs expected lifetime offspring production discounted by the background population growth rate. Here, we draw attention to the discounted reproductive number by providing an explicit definition and a systematic application framework. We describe how the discounted reproductive number overcomes the limitations of both the standard reproductive numbers and proliferation rates, and show that is closely connected to FisherÆs reproductive values for different life-history stages PMID:19364158
Amelioration of Reproduction-Associated Oxidative Stress in a Viviparous Insect Is Critical to Prevent Reproductive Senescence
Attardo, Geoffrey M.; Medlock, Jan; Aksoy, Serap
Impact of reproductive processes upon female health has yielded conflicting results; particularly in relation to the role of reproduction-associated stress. We used the viviparous tsetse fly to determine if lactation, birth and involution lead to damage from oxidative stress (OS) that impairs subsequent reproductive cycles. Tsetse females carry an intrauterine larva to full term at each pregnancy cycle, and lactate to nourish them with milk secretions produced by the accessory gland (?=?milk gland) organ. Unlike most K-strategists, tsetse females lack an apparent period of reproductive senescence allowing the production of 8¢10 progeny over their entire life span. In a lactating female, over 47% of the maternal transcriptome is associated with the generation of milk proteins. The resulting single larval offspring weighs as much as the mother at birth. In studying this process we noted an increase in specific antioxidant enzyme (AOE) transcripts and enzymatic activity at critical times during lactation, birth and involution in the milk gland/fat body organ and the uterus. Suppression of superoxide dismutase (sod) decreased fecundity in subsequent reproductive cycles in young mothers and nearly abolished fecundity in geriatric females. Loss of fecundity was in part due to the inability of the mother to produce adequate milk to support larval growth. Longevity was also impaired after sod knockdown. Generation of OS in virgin females through exogenous treatment with hydrogen peroxide at times corresponding to pregnancy intervals reduced survival, which was exacerbated by sod knockdown. AOE expression may prevent oxidative damage associated with the generation of nutrients by the milk gland, parturition and milk gland breakdown. Our results indicate that prevention of OS is essential for females to meet the growing nutritional demands of juveniles during pregnancy and to repair the damage that occurs at birth. This process is particularly important for females to remain fecund during the latter portion of their lifetime. PMID:24763119
Life history of the long-lived gynodioecious cushion plant Silene acaulis (Caryophyllaceae), inferred from size-based population projection matrices.
Morris, W; Doak, D
Alpine plants often appear to have long life-spans as an adaptation to harsh and unpredictable environmental conditions, yet many lack reliable indicators of age that would make it possible to determine their true longevity. Their extended life-spans also pose problems for measuring lifetime reproductive success, a key component of breeding system evolution in species such as the gynodioecious cushion plant Silene acaulis. For a population of S. acaulis in south-central Alaska, we applied a recently derived analytical approach using size-based population projection matrices that allowed us to estimate: (1) the relationship between cushion diameter and age; and (2) lifetime reproductive success through seed production by females relative to hermaphrodites. Because of a combination of slow growth, frequent shrinkage, and extremely high adult survival, we estimate that the largest cushions in our study population exceed 300 yr in age, and some may live substantially longer, despite the seemingly inhospitable alpine environment they inhabit. Females are estimated to produce 4.4 times as many offspring via seed production over the course of their lives as do hermaphrodites, a difference that is more than sufficient to assure the persistence of females despite their inability to transmit genes through pollen. These results highlight the utility of size-based projection matrices for studying the life histories of herbaceous perennials whose life-span and lifetime reproductive success cannot be determined easily by any other means. PMID:21684962
Individual variation in reproductive costs of reproduction: high-quality females always do better
Sandra Hamel; Steeve D. C¶tķ; Jean-Michel Gaillard; Marco Festa-Bianchet
Summary 1. Although life-history theory predicts substantial costs of reproduction, individuals often show positive correlations among life-history traits, rather than trade-offs. The apparent absence of reproductive costs may result from heterogeneity in individual quality. 2. Using detailed longitudinal data from three contrasted ungulate populations (mountain goats, Oreamnos americanus ; bighorn sheep, Ovis canadensis ; and roe deer, Capreolus capreolus ),
Ō??The Calamity of So Long LifeŌ?Ø: Life Histories, Contaminants, and Potential Emerging Threats to Long-lived Vertebrates
NSDL National Science Digital Library
Christopher L. Rowe (University of Maryland; )
Persistent contaminants are ubiquitous in the environment, often present at concentrations that may jeopardize reproductive fitness only after long periods of exposure. As the duration of exposure is largely regulated by life span, long-lived species of high trophic status, such as many reptiles, birds, and mammals, may be at risk of reduced fitness and population decline. Delayed maturation and iteroparity confer the potential for cumulative effects to be expressed prior to reproduction, and large parental investments in yolk and milk may threaten offspring because of exposure during critical developmental periods. Long generation times may delay emergence of obvious effects on populations, perhaps eluding early intervention, while constraining rates at which populations may recover if conditions subsequently improve. Life history theory thus suggests that the suite of traits that optimized reproductive fitness throughout long-lived species' evolutionary histories may ultimately put them in peril in the modern, anthropogenically altered environment.
Eckart Voland
Abstract Evolutionary ecology of human reproduction is defined as the application of natural selection theory to the study of human reproductive strategies and decision-making in an ecological context. The basic Darwinian assumption is that humans-like all other organisms-are designed to maximize their inclusive fitness within the ecological constraints to which they are exposed. Life history theory, which identifies trade-off problems
Hormesis depends upon the life-stage and duration of exposure: Examples for a pesticide and a nanomaterial.
Tyne, William; Little, Simon; Spurgeon, David J; Svendsen, Claus
Tests to assess toxic effects on the reproduction of adult C. elegans after 72h exposure for two chemicals, (3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU)), also known as diuron, and silver nanoparticles (Ag NPs) indicated potential, although not significant hormesis. Follow up toxicity tests comparing the potential hormesis concentrations with controls at high replication confirmed that the stimulatory effect was repeatable and also statistically significant within the test. To understand the relevance of the hormesis effects for overall population fitness, full life-cycle toxicity tests were conducted for each chemical. When nematodes were exposed to DCMU over the full life-span, the hormesis effect for reproduction seen in short-term tests was no longer evident. Further at the putative hormesis concentrations, a negative effect of DCMU on time to maturation was also seen. For the Ag NPs, the EC50 for effects on reproduction in the life-cycle exposure was substantially lower than in the short-term test, the EC50s estimated by a three parameter log logistic model being 2.9mg/L and 0.75mg/L, respectively. This suggests that the level of toxicity for Ag NPs for C. elegans reproduction is dependant on the life stage exposed and possibly the duration of the exposure. Further, in the longer duration exposures, hormesis effects on reproduction seen in the short-term exposures were no longer apparent. Instead, all concentrations reduced both overall brood size and life-span. These results for both chemicals suggest that the hormesis observed for a single endpoint in short-term exposure may be the result of a temporary reallocation of resources between traits that are not sustained over the full life-time. Such reallocation is consistent with energy budget theories for organisms subject to toxic stress. PMID:26057078
Scanning Probe Alloying Nanolithography (SPAN)
Lee, Hyungoo
Micro-Electro-Mechanical System MLS Motorized Linear Stage MPU Microprocessor unit NEMS Nano-Electro-Mechanical System NSOM Near-Field Scanning Optical Microscope PVDF Polyvinylidene difluoride SEM Scanning electron microscope SPAN Scanning.... AFM is a type of Scanning Probe Microscope (SPM). The SPM covers technologies to image and measure surfaces on a micro- or nano-scale. There are three most common types of SPM; Scanning Tunneling Microscope (STM), Atomic Force Microscope (AFM...
An empirical test of evolutionary theories for reproductive senescence and reproductive effort in the garter snake Thamnophis elegans.
Sparkman, Amanda M; Arnold, Stevan J; Bronikowski, Anne M
Evolutionary theory predicts that differential reproductive effort and rate of reproductive senescence will evolve under different rates of external mortality. We examine the evolutionary divergence of age-specific reproduction in two life-history ecotypes of the western terrestrial garter snake, Thamnophis elegans. We test for the signature of reproductive senescence (decreasing fecundity with age) and increasing reproductive effort with age (increasing reproductive productivity per gram female) in replicate populations of two life-history ecotypes: snakes that grow fast, mature young and have shorter lifespans, and snakes that grow slow, mature late and have long lives. The difference between life-history ecotypes is due to genetic divergence in growth rate. We find (i) reproductive success (live litter mass) increases with age in both ecotypes, but does so more rapidly in the fast-growth ecotype, (ii) reproductive failure increases with age in both ecotypes, but the proportion of reproductive failure to total reproductive output remains invariant, and (iii) reproductive effort remains constant in fast-growth individuals with age, but declines in slow-growth individuals. This illustration of increasing fecundity with age, even at the latest ages, deviates from standard expectations for reproductive senescence, as does the lack of increases in reproductive effort. We discuss our findings in light of recent theories regarding the phenomenon of increased reproduction throughout life in organisms with indeterminate growth and its potential to offset theoretical expectations for the ubiquity of senescence. PMID:17251099
An empirical test of evolutionary theories for reproductive senescence and reproductive effort in the garter snake Thamnophis elegans
Sparkman, Amanda M; Arnold, Stevan J; Bronikowski, Anne M
Evolutionary theory predicts that differential reproductive effort and rate of reproductive senescence will evolve under different rates of external mortality. We examine the evolutionary divergence of age-specific reproduction in two life-history ecotypes of the western terrestrial garter snake, Thamnophis elegans. We test for the signature of reproductive senescence (decreasing fecundity with age) and increasing reproductive effort with age (increasing reproductive productivity per gram female) in replicate populations of two life-history ecotypes: snakes that grow fast, mature young and have shorter lifespans, and snakes that grow slow, mature late and have long lives. The difference between life-history ecotypes is due to genetic divergence in growth rate. We find (i) reproductive success (live litter mass) increases with age in both ecotypes, but does so more rapidly in the fast-growth ecotype, (ii) reproductive failure increases with age in both ecotypes, but the proportion of reproductive failure to total reproductive output remains invariant, and (iii) reproductive effort remains constant in fast-growth individuals with age, but declines in slow-growth individuals. This illustration of increasing fecundity with age, even at the latest ages, deviates from standard expectations for reproductive senescence, as does the lack of increases in reproductive effort. We discuss our findings in light of recent theories regarding the phenomenon of increased reproduction throughout life in organisms with indeterminate growth and its potential to offset theoretical expectations for the ubiquity of senescence. PMID:17251099
Assessing the impacts of dimethoate on rotifers' reproduction through the pre-exposure history.
Guo, Ruixin; Chen, Jianqiu
Organism usually undergoes an exposure of environmental pollution after a maternal exposure before birth. Traditional toxicological studies often initiated with rotifer neonates derived from the unexposed mothers while ignoring the pre-exposure (maternal exposure). The present study assessed the effect of dimethoate on the reproduction of the rotifer Brachionus calyciflorus, considering how the pre-exposure occurred in the parental generation influenced the subsequent impact. The F0 generation rotifers were exposed to the pesticide at five concentrations until the first F1 generation rotifers were reproduced. The neonates (F1 generation) were then exposed to the pesticide at the corresponding concentrations. The offspring reproduction, the time begins to reproduce, the duration of the reproductive period and the lifespan of the F1 generation rotifers were evaluated. Our results indicated that dimethoate influenced the maturation and reproduction of the rotifers. The highest concentration (1.8 mg L(-1)) of dimethoate caused an inhibition in the offspring reproduction, shortened the life span and reduced the duration of the reproductive period. In addition, of particular interest in our study was that reproduction is also accelerated by the lowest concentration (0.2 mg L(-1)). However, the pre-exposure had a significant effect on the subsequent impact. The dimethoate pre-exposure increased the impacts when the F1 generation rotifers were exposed to the substance, even at the same concentrations as in pre-exposure. It suggests that the maternal exposure history before birth is also important and has the long-lasting consequence from one generation to another. PMID:25450934
Racial and Ethnic Health Disparities in Reproductive Medicine: An Evidence-Based Overview
Owen, Carter M.; Goldstein, Ellen H.; Clayton, Janine A.; Segars, James H.
Racial and ethnic health disparities in reproductive medicine exist across the life span and are costly and burdensome to our healthcare system. Reduction and ultimate elimination of health disparities is a priority of the National Institutes of Health who requires reporting of race and ethnicity for all clinical research it supports. Given the increasing rates of admixture in our population, the definition and subsequent genetic significance of self-reported race and ethnicity used in health disparity research is not straightforward. Some groups have advocated using self-reported ancestry or carefully selected single-nucleotide polymorphisms, also known as ancestry informative markers, to sort individuals into populations. Despite the limitations in our current definitions of race and ethnicity in research, there are several clear examples of health inequalities in reproductive medicine extending from puberty and infertility to obstetric outcomes. We acknowledge that socioeconomic status, education, insurance status, and overall access to care likely contribute to the differences, but these factors do not fully explain the disparities. Epigenetics may provide the biologic link between these environmental factors and the transgenerational disparities that are observed. We propose an integrated view of health disparities across the life span and generations focusing on the metabolic aspects of fetal programming and the effects of environmental exposures. Interventions aimed at improving nutrition and minimizing adverse environmental exposures may act synergistically to reverse the effects of these epigenetic marks and improve the outcome of our future generations. PMID:23934691
Life Table and Predation of Lemnia biplagiata (Coleoptera: Coccinellidae) Fed on Aphis gossypii (Homoptera: Aphididae) with a Proof on Relationship Among Gross Reproduction Rate, Net Reproduction Rate, and Preadult Survivorship
Jih-Zu Yu; Hsin Chi; Bing-Huei Chen
The life history and predation rate of Lemnia biplagiata (Swartz) fed on Aphis gossypii Glover was studied at 25C in the laboratory. The raw data were analyzed based on the age-stage, two-sex life table to take the variable developmental rate among individuals and both sexes into consideration. The intrinsic rate of increase (r) is 0.1570 d1, the ▐nite rate of
Contrasting Life Histories in Neighbouring Populations of a Large Mammal
Tom H. E. Mason; Roberta Chirichella; Shane A. Richards; Philip A. Stephens; Stephen G. Willis; Marco Apollonio
BackgroundA fundamental life history question is how individuals should allocate resources to reproduction optimally over time (reproductive allocation). The reproductive restraint hypothesis predicts that reproductive effort (RE; the allocation of resources to current reproduction) should peak at prime-age, whilst the terminal investment hypothesis predicts that individuals should continue to invest more resources in reproduction throughout life, owing to an ever-decreasing
Reproductive Hazards in the Lab Reproductive Hazards
de Lijser, Peter
and pesticides have been shown to have effects on human reproductive systems. Organic solvents, such as xyleneReproductive Hazards in the Lab Reproductive Hazards The term reproductive hazard refers to agents (radiation, x-rays, chemicals or biologicals) that affect the reproductive health of women or men to have
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Early reproductive investment, senescence and lifetime reproductive success in female Asian elephants
Hayward, A D; Mar, K U; Lahdenperõ, M; Lummaa, V
The evolutionary theory of senescence posits that as the probability of extrinsic mortality increases with age, selection should favour early-life over late-life reproduction. Studies on natural vertebrate populations show early reproduction may impair later-life performance, but the consequences for lifetime fitness have rarely been determined, and little is known of whether similar patterns apply to mammals which typically live for several decades. We used a longitudinal dataset on Asian elephants (Elephas maximus) to investigate associations between early-life reproduction and female age-specific survival, fecundity and offspring survival to independence, as well as lifetime breeding success (lifetime number of calves produced). Females showed low fecundity following sexual maturity, followed by a rapid increase to a peak at age 19 and a subsequent decline. High early life reproductive output (before the peak of performance) was positively associated with subsequent age-specific fecundity and offspring survival, but significantly impaired a female's own later-life survival. Despite the negative effects of early reproduction on late-life survival, early reproduction is under positive selection through a positive association with lifetime breeding success. Our results suggest a trade-off between early reproduction and later survival which is maintained by strong selection for high early fecundity, and thus support the prediction from life history theory that high investment in reproductive success in early life is favoured by selection through lifetime fitness despite costs to later-life survival. That maternal survival in elephants depends on previous reproductive investment also has implications for the success of (semi-)captive breeding programmes of this endangered species. PMID:24580655
Early reproductive investment, senescence and lifetime reproductive success in female Asian elephants.
Hayward, A D; Mar, K U; Lahdenperõ, M; Lummaa, V
The evolutionary theory of senescence posits that as the probability of extrinsic mortality increases with age, selection should favour early-life over late-life reproduction. Studies on natural vertebrate populations show early reproduction may impair later-life performance, but the consequences for lifetime fitness have rarely been determined, and little is known of whether similar patterns apply to mammals which typically live for several decades. We used a longitudinal dataset on Asian elephants (Elephas maximus) to investigate associations between early-life reproduction and female age-specific survival, fecundity and offspring survival to independence, as well as lifetime breeding success (lifetime number of calves produced). Females showed low fecundity following sexual maturity, followed by a rapid increase to a peak at age 19 and a subsequent decline. High early life reproductive output (before the peak of performance) was positively associated with subsequent age-specific fecundity and offspring survival, but significantly impaired a female's own later-life survival. Despite the negative effects of early reproduction on late-life survival, early reproduction is under positive selection through a positive association with lifetime breeding success. Our results suggest a trade-off between early reproduction and later survival which is maintained by strong selection for high early fecundity, and thus support the prediction from life history theory that high investment in reproductive success in early life is favoured by selection through lifetime fitness despite costs to later-life survival. That maternal survival in elephants depends on previous reproductive investment also has implications for the success of (semi-)captive breeding programmes of this endangered species. PMID:24580655
Reproductive Toxicity of Endosulfan: Implication From Germ Cell Apoptosis Modulated by Mitochondrial Dysfunction and Genotoxic Response Genes in Caenorhabditis elegans.
Du, Hua; Wang, Meimei; Wang, Lei; Dai, Hui; Wang, Min; Hong, Wei; Nie, Xinxin; Wu, Lijun; Xu, An
Endosulfan as a new member of persistent organic pollutants has been shown to induce reproductive dysfunction in various animal models. However, the action mechanism of endosulfan-produced reproductive toxicity remains largely unknown. This study was focused on investigating the reproductive toxicity induced by ?-endosulfan and clarifying the role of mitochondria and genotoxic response genes in germ cell apoptosis of Caenorhabditis elegans. Our data showed that endosulfan induced a dose-dependent decrease of life span, fecundity, and hatchability, whereas the germ cell apoptosis was dose-dependently increased. The mitochondria membrane potential was disrupted by endosulfan, leading to a significant increase of germ cell apoptosis in mev-1(kn-1) mutant. However, the apoptotic effects of endosulfan were blocked in mutants of cep-1(w40), egl-1(n487), and hus-1(op241), indicating conserved genotoxic response genes played an essential role in endosulfan-induced germ cell apoptosis. Furthermore, exposure to endosulfan induced the accumulation of HUS-1::GFP foci and the germ cell cycle arrest. These findings provided clear evidence that endosulfan caused significant adverse effects on the reproduction system of C. elegans and increased germ cell apoptosis, which was regulated by mitochondrial dysfunction and DNA damage response genes. This study may help to understand the signal transduction pathways involved in endosulfan-induced reproductive toxicity. PMID:25666835
Long-Term Effects of Environmental Endocrine Disruptors on Reproductive Physiology and Behavior
Patisaul, Heather B.; Adewale, Heather B.
It is well established that, over the course of development, hormones shape the vertebrate brain such that sex specific physiology and behaviors emerge. Much of this occurs in discrete developmental windows that span gestation through the prenatal period, although it is now becoming clear that at least some of this process continues through puberty. Perturbation of this developmental progression can permanently alter the capacity for reproductive success. Wildlife studies have revealed that exposure to endocrine disrupting compounds (EDCs), either naturally occurring or man made, can profoundly alter reproductive physiology and ultimately impact entire populations. Laboratory studies in rodents and other species have elucidated some of the mechanisms by which this occurs and strongly indicate that humans are also vulnerable to disruption. Use of hormonally active compounds in human medicine has also unfortunately revealed that the developing fetus can be exposed to and affected by endocrine disruptors, and that it might take decades for adverse effects to manifest. Research within the field of environmental endocrine disruption has also contributed to the general understanding of how early life experiences can alter reproductive physiology and behavior through non-genomic, epigenetic mechanisms such as DNA methylation and histone acetylation. These types of effects have the potential to impact future generations if the germ line is affected. This review provides an overview of how exposure to EDCs, particularly those that interfere with estrogen action, impacts reproductive physiology and behaviors in vertebrates. PMID:19587848
Avoiding Differences Spanning Trees in Grid Graphs
Zeilberger, Doron
Avoiding Differences Spanning Trees in Grid Graphs The Firefighter Problem Automated Proof and Discovery #12;Avoiding Differences Spanning Trees in Grid Graphs The Firefighter Problem Automated Proof and Discovery #12;Avoiding Differences Spanning Trees in Grid Graphs The Firefighter Problem Outline 1 Avoiding
Several DBPs, particularly the disubstituted haloacetic acids (e.g. dibromoacetic acid, bromochloroacetic acid), have been shown to produce reproductive and developmental toxicity in laboratory animals. In 1993, an expert panel convened by the EPA and the International Life Scien...
Reproductive cessation in female mammals.
Packer, C; Tatar, M; Collins, A
In female mammals, fertility declines abruptly at an advanced age. The human menopause is one example, but reproductive cessation has also been documented in non-human primates, rodents, whales, dogs, rabbits, elephants and domestic livestock. The human menopause has been considered an evolutionary adaptation, assuming that elderly women avoid the increasing complications of continued childbirth to better nurture their current children and grandchildren. But an abrupt reproductive decline might be only a non-adaptive by-product of life-history patterns. Because so many individuals die from starvation, disease and predation, detrimental genetic traits can persist (or even be favoured) as long as their deleterious effects are delayed until an advanced age is reached, and, for a given pattern of mortality, there should be an age by which selection would be too weak to prevent the onset of reproductive senescence. We provide a systematic test of these alternatives using field data from two species in which grandmothers frequently engage in kin-directed behaviour. Both species show abrupt age-specific changes in reproductive performance that are characteristic of menopause. But elderly females do not suffer increased mortality costs of reproduction, nor do post-reproductive females enhance the fitness of grandchildren or older children. Instead, reproductive cessation appears to result from senescence. PMID:9572138
... your body Your reproductive health How the female reproductive system works Vaginal infections What is PCOS? Puberty Getting ... Your reproductive health What, exactly, is the female reproductive system? It is all the parts of your body ...
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BioMed Central contains hundreds of important online journals in its archives, and Reproductive Health is certainly one that visitors will want to look over when they have a few moments. Reproductive Health is the official journal of the Geneva Foundation for Medical Education and Research, and was started in June 2004. It covers all aspects of human reproduction, and recent pieces have dealt with cervical cancer, maternity care, and other related topics. Visitors can view the ten most accessed articles from the journal, sign up to receive an RSS feed of the latest articles, and also email articles to friends and colleagues. For those who might be interested in submitting an article for consideration, they can also do that via this site.
NSDL National Science Digital Library
C-SPAN has given viewers programs like the celebrated "BookTV" and "Booknotes" and now they have come out with "The Communicators". This program features a half-hour interview with "the people who shape our digital future." Interviews include the acting chairman of the Federal Communications Commission (FCC), Fred Humphries of Microsoft Corporation's Federal Affairs division, and legislators concerned with such matters. At the top of the site's homepage, visitors will find the latest interview in the series, complete with additional relevant web resources. Further down the homepage, visitors will find a link to their podcasts, along with a complete listing of "Recent Events". The site is rounded out by a detailed set of "Web Resources" related to the federal government, which can be found on the right-hand side of the page.
Symptomatic improvement, increased life-span and sustained cell homing in amyotrophic lateral sclerosis after transplantation of human umbilical cord blood cells genetically modified with adeno-viral vectors expressing a neuro-protective factor and a neural cell adhesion molecule.
Islamov, Rustem Robertovich; Rizvanov, Albert Anatolyevich; Mukhamedyarov, Marat Alexandrovich; Salafutdinov, Ilnur Ildusovich; Garanina, Ekaterina Evgenevna; Fedotova, Valeria Yuryevna; Solovyeva, Valeria Vladimirovna; Mukhamedshina, Yana Olegovna; Safiullov, Zufar Zufarovich; Izmailov, Andrey Alexandrovich; Guseva, Daria Sergeevna; Zefirov, Andrey Lvovich; Kiyasov, Andrey Pavlovich; Palotas, Andras
Amyotrophic lateral sclerosis (ALS) is an incurable, chronic, fatal neuro-degenerative disease characterized by progressive loss of moto-neurons and paralysis of skeletal muscles. Reactivating dysfunctional areas is under earnest investigation utilizing various approaches. Here we present an innovative gene-cell construct aimed at reviving inert structure and function. Human umbilical cord blood cells (hUCBCs) transduced with adeno-viral vectors encoding human VEGF, GDNF and/or NCAM genes were transplanted into transgenic ALS mice models. Significant improvement in behavioral performance (open-field and grip-strength tests), as well as increased life-span was observed in rodents treated with NCAM-VEGF or NCAM-GDNF co-transfected cells. Active trans-gene expression was found in the spinal cord of ALS mice 10 weeks after delivering genetically modified hUCBCs, and cells were detectable even 5 months following transplantation. Our gene-cell therapy model yielded prominent symptomatic control and prolonged life-time in ALS. Incredible survivability of xeno-transpanted cells was also observed without any immune-suppression. These results suggest that engineered hUCBCs may offer effective gene-cell therapy in ALS. PMID:25619885
Reproductive strategies of Atlantic salmon: ecology and evolution
Ian A. Fleming
Atlantic salmon (Salmo solar, Salmonidae) show a diversity of life history, behavioural and morphological adaptations for reproduction which have evolved as an outcome of competition to maximize reproductive success. Reproductive traits of females have been shaped principally by natural selection for offspring production and survival, those of males by sexual selection for access to matings. Female Atlantic salmon invest approximately
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
SHARP OBLIQUE PERSPECTIVE OF DECK AND APPROACH SPANS ALONG WITH PRINCIPLE CANTILEVER SPAN SHARP OBLIQUE PERSPECTIVE OF DECK AND APPROACH SPANS ALONG WITH PRINCIPLE CANTILEVER SPAN SHARP OBLIQUE PERSPECTIVE OF DECK AND APPROACH SPANS ALONG WITH PRINCIPLE CANTILEVER SPAN SHARP OBLIQUE PERSPECTIVE OF DECK AND APPROACH SPANS ALONG WITH PRINCIPLE CANTILEVER SPAN SHARP OBLIQUE PERSPECTIVE OF DECK AND APPROACH SPANS ALONG WITH PRINCIPLE CANTILEVER SPAN SHARP OBLIQUE PERSPECTIVE OF DECK AND APPROACH SPANS ALONG WITH PRINCIPLE CANTILEVER SPAN vSHARP OBLIQUE PERSPECTIVE OF DECK AND APPROACH SPANS ALONG WITH PRINCIPLE CANTILEVER SPAN SHARP OBLIQUE PERSPECTIVE OF DECK AND APPROACH SPANS ALONG WITH PRINCIPLE CANTILEVER SPAN SHARP OBLIQUE PERSPECTIVE OF DECK AND APPROACH SPANS ALONG WITH PRINCIPLE CANTILEVER SPAN - Snake River Bridge at Lyons' Ferry, State Route 261 spanning Snake River, Starbuck, Columbia County, WA
NED <span class="hlt">Literature <span class="hlt">Searches
Using NED to <span class="hlt">Search the Extragalactic <span class="hlt">Literature (Latest Revision: 12 December 2013) Types of <span class="hlt">Searches There are several ways to <span class="hlt">search NED's directory of the extragalactic...
Current Development in Reproductive Toxicity Testing of Pesticides
A protocol to evaluate the potential developmental and reproductive effects of test chemicals has been developed by the Life Stages Task Force of the International Life Sciences Institute (ILSI)/Health and Environmental Sciences Institute (HESI) Agricultural Chemical Safety Asses...
Domenico Parisi; Matthew Schlesinger
Artificial Life is the study of all phenomena of the living world through their reproduction in artificial systems. We argue that Artificial Life models of evolution and development offer a new set of theoretical and methodological tools for investigating PiagetÆs ideas. The concept of an Artificial Life Neural Network (ALNN) is first introduced, and contrasted with the study of other
Infectious Diseases, Reproductive Effort and the Cost of Reproduction in Birds
L. Gustafsson; D. Nordling; M. S. Andersson; B. C. Sheldon; A. Qvarnstrom
Reproductive effort can have profound effects on subsequent performance. Field experiments on the collared flycatcher (Ficedula albicollis) have demonstrated a number of trade-offs between life-history traits at different ages. The mechanism by which reproductive effort is mediated into future reproductive performance remains obscure. Anti-parasite adaptations such as cell-mediated immunity may probably also be costly. Hence the possibility exists of a
Extended attention span training system
NASA Technical Reports Server (NTRS)
Pope, Alan T.; Bogart, Edward H.
Attention Deficit Disorder (ADD) is a behavioral disorder characterized by the inability to sustain attention long enough to perform activities such as schoolwork or organized play. Treatments for this disorder include medication and brainwave biofeedback training. Brainwave biofeedback training systems feed back information to the trainee showing him how well he is producing the brainwave pattern that indicates attention. The Extended Attention Span Training (EAST) system takes the concept a step further by making a video game more difficult as the player's brainwaves indicate that attention is waning. The trainee can succeed at the game only by maintaining an adequate level of attention. The EAST system is a modification of a biocybernetic system that is currently being used to assess the extent to which automated flight management systems maintain pilot engagement. This biocybernetic system is a product of a program aimed at developing methods to evaluate automated flight deck designs for compatibility with human capabilities. The EAST technology can make a contribution in the fields of medical neuropsychology and neurology, where the emphasis is on cautious, conservative treatment of youngsters with attention disorders.
Individual variation in reproductive costs of reproduction: high-quality females always do better.
Hamel, Sandra; C¶tķ, Steeve D; Gaillard, Jean-Michel; Festa-Bianchet, Marco
1. Although life-history theory predicts substantial costs of reproduction, individuals often show positive correlations among life-history traits, rather than trade-offs. The apparent absence of reproductive costs may result from heterogeneity in individual quality. 2. Using detailed longitudinal data from three contrasted ungulate populations (mountain goats, Oreamnos americanus; bighorn sheep, Ovis canadensis; and roe deer, Capreolus capreolus), we assessed how individual quality affects the probability of detecting a cost of current reproduction on future reproduction for females. We used a composite measure of individual quality based on variations in longevity (all species), success in the last breeding opportunity before death (goats and sheep), adult mass (all species), and social rank (goats only). 3. In all species, high-quality females consistently had a higher probability of reproduction, irrespective of previous reproductive status. In mountain goats, we detected a cost of reproduction only after accounting for differences in individual quality. Only low-quality female goats were less likely to reproduce following years of breeding than of nonbreeding. Offspring survival was lower in bighorn ewes following years of successful breeding than after years when no lamb was produced, but only for low-quality females, suggesting that a cost of reproduction only occurred for low-quality females. 4. Because costs of reproduction differ among females, studies of life-history evolution must account for heterogeneity in individual quality. PMID:18700872
Metric half-span model support system
NASA Technical Reports Server (NTRS)
Jackson, C. M., Jr.; Dollyhigh, S. M.; Shaw, D. S. (inventors)
A model support system used to support a model in a wind tunnel test section is described. The model comprises a metric, or measured, half-span supported by a nonmetric, or nonmeasured half-span which is connected to a sting support. Moments and forces acting on the metric half-span are measured without interference from the support system during a wind tunnel test.
Trusted Spanning Tree for Delay Tolerant MANETs
A. Piyatumrong; Pascal Bouvry; Frķdķric Guinand; K. Lavangnananda
Quality of service is an important issue in Delay Tole- rant MANETs. This work aims at increasing the QoS in such networks by relying on spanning forests (DA-GRS). The existing algorithms are improved by introducing the notion of trust into the spanning forest and choosing the most robust (trustable) spanning trees among existing op- portunities. The robustness\\/quality of the tree
Quantum Verification of Minimum Spanning Tree
Mark Heiligman
Previous studies has shown that for a weighted undirected graph having $n$ vertices and $m$ edges, a minimal weight spanning tree can be found with $O^*(\\sqrt{mn})$ calls to the weight oracle. The present note shows that a given spanning tree can be verified to be a minimal weight spanning tree with only $O(n\\bigr)$ calls to the weight oracle and $O(n+\\sqrt{m}\\log n)$ total work.
Current developments in reproductive toxicity testing of pesticides
Ralph L. Cooper
A protocol to evaluate the potential developmental and reproductive effects of test chemicals has been developed by the Life Stages Task Force of the International Life Sciences Institute (ILSI)\\/Health and Environmental Sciences Institute (HESI) Agricultural Chemical Safety Assessment (ACSA) Technical Committee. Since the original publication, several international groups have provided public comment on conducting the test. The extended one-generation reproductive
Manipulating reproductive effort leads to changes in female reproductive scheduling but not oxidative stress
Aloise King, Edith D; Garratt, Michael; Brooks, Robert
The trade-off between reproductive investment and lifespan is the single most important concept in life-history theory. A variety of sources of evidence support the existence of this trade-off, but the physiological costs of reproduction that underlie this relationship remain poorly understood. The Free Radical Theory of Ageing suggests that oxidative stress, which occurs when there is an imbalance between the production of damaging Reactive Oxygen Species (ROS) and protective antioxidants, may be an important mediator of this trade-off. We sought to test this theory by manipulating the reproductive investment of female mice (Mus musculus domesticus) and measuring the effects on a number of life history and oxidative stress variables. Females with a greater reproductive load showed no consistent increase in oxidative damage above females who had a smaller reproductive load. The groups differed, however, in their food consumption, reproductive scheduling and mean offspring mass. Of particular note, females with a very high reproductive load delayed blastocyst implantation of their second litter, potentially mitigating the costs of energetically costly reproductive periods. Our results highlight that females use strategies to offset particularly costly periods of reproduction and illustrate the absence of a simple relationship between oxidative stress and reproduction. PMID:24324867
Comparative toxicant sensitivity of sexual and asexual reproduction in the rotifer Brachionus calyciflorus
Terry W. Snell; Maria Jose Carmona
Cyclically parthenogenetic zooplankters like rotifers are important tools for assessing toxicity in aquatic environments. Sexual reproduction is an essential component of rotifer life cycles, but current toxicity tests utilize only asexual reproduction. The authors compared the effects of four toxicants on asexual and sexual reproduction of the rotifer Brachionus calyciflorus. Toxicants had a differential effect on sexual and asexual reproduction,
Stability of self-esteem across the life span.
Trzesniewski, Kali H; Donnellan, M Brent; Robins, Richard W
Two studies examined the rank-order stability of self-esteem from age 6 to 83: Study 1 was a meta-analysis of 50 published articles (N = 29,839) and Study 2 analyzed data from 4 large national studies (N = 74,381). Self-esteem showed substantial continuity over time (disattenuated correlations ranged from the .50s to .70s), comparable to the stability found for personality traits. Both studies provided evidence for a robust developmental trend: Self-esteem stability was low during childhood, increased throughout adolescence and young adulthood, and declined during midlife and old age. This trend could not be explained by age differences in the reliability of self-esteem measures, and generally replicated across gender, ethnicity, self-esteem scale, nationality (U.S. vs. non-U.S.), and year of publication. PMID:12518980
IQ and Ability Across the Adult Life Span
Sallie Baxendale
The experience of cognitive decline can be a potent source of anxiety and concern for many people. While an IQ consistent with estimated optimal levels or previously recorded scores may indicate no significant change in cognitive function, the patient may be accurately reporting a normal age-related deterioration in actual ability. The aim of this article is to chart the age-related
Developmental and behavioral disorders through the life span.
Stein, David S; Blum, Nathan J; Barbaresi, William J
Developmental and behavioral disorders including intellectual disability, learning disabilities, and attention-deficit/hyperactivity disorder are highly prevalent, chronic health conditions. Despite being versed in caring for children with these conditions, pediatricians might be less prepared for challenging questions from families about the long-term course of these conditions and what can be done to improve outcomes. Through this state-of-the-art review, we provide clinicians with an understanding of the course of these conditions and adult outcomes in several areas including vocational, social, and health domains. We also provide a review of the most current research examining factors that predict or mediate adult outcomes for people with intellectual disability, learning disabilities, and attention-deficit/hyperactivity disorder. On the basis of the current literature, we offer practice recommendations aimed at optimizing adult outcomes for those with these disorders. PMID:21768324
Emotion recognition in music changes across the adult life span.
Lima, Cesar F; Castro, Sao Luis
In comparison with other modalities, the recognition of emotion in music has received little attention. An unexplored question is whether and how emotion recognition in music changes as a function of ageing. In the present study, healthy adults aged between 17 and 84 years (N=114) judged the magnitude to which a set of musical excerpts (Vieillard et al., 2008) expressed happiness, peacefulness, sadness and fear/threat. The results revealed emotion-specific age-related changes: advancing age was associated with a gradual decrease in responsiveness to sad and scary music from middle age onwards, whereas the recognition of happiness and peacefulness, both positive emotional qualities, remained stable from young adulthood to older age. Additionally, the number of years of music training was associated with more accurate categorisation of the musical emotions examined here. We argue that these findings are consistent with two accounts on how ageing might influence the recognition of emotions: motivational changes towards positivity and, to a lesser extent, selective neuropsychological decline. PMID:21547762
Liver X Receptor Alpha Associates With Human Life Span
Simon P. Mooijaart; Maris Kuningas; Rudi G. J. Westendorp; Jeanine J. Houwing-Duistermaat; P. Eline Slagboom; Patrick C. N. Rensen; Diana van Heemst
In the nematode Caenorhabditis elegans, nuclear hormone receptor DAF-12 regulates the deci- sion to go into a resistant dauer diapause, in which the worm exhibits a decreased rate of aging. Using sequence similarity searches, we previously identified the liver X receptor alpha (LXRa )a s one of the human nuclear hormone receptors the protein sequence of which is most similar
Improved Therapies Have Extended Life Spans of Childhood Cancer Survivors
... diagnosis," said the study's lead author, Dr. Gregory Armstrong. He is a pediatric oncologist at St. Jude ... overall toxicity of treatment in more modern eras," Armstrong said. The findings were scheduled for presentation Sunday ...
Self-determination -- A life-span perspective
Palmer, Susan B.
, proposed that volitional self- determined actions can be grouped into four characteristics: I. Acting autonomously, with a minimum of support, if needed 2. Acting in a self- regulated manner, with personal con- trol over one's actions 3. Initiating..., to explore, and to learn" (Ryan & Deci, 2000, p. 70). Burt this theory may not adequately describe the need for people with disabilities to be empowered( beyond self-direction within their lives. For people with disabilities, self-determination has a broader...
Unintentional home injuries across the life span: problems and solutions.
Gielen, Andrea C; McDonald, Eileen M; Shields, Wendy
Home injuries cause more than 30,000 deaths and 12 million nonfatal injuries annually in the United States. They generate an estimated $222 billion in lifetime costs annually. Despite some data limitations in documenting home as the location of an injury, much progress has been made in identifying effective prevention strategies that reduce injury or mitigate risk behaviors. The current interest in public health in the role of housing in health offers unparalleled opportunities for injury prevention professionals concerned with home injuries. Sharing the science of injury prevention with the wide array of professionals-such as architects, home builders, home visitors, and fire and emergency medical services providers-who create home environments and interact with residents could be a useful approach. A collaborative national effort to reduce the burden of home injuries is needed. PMID:25581150
Reproductive and developmental toxicity and bioconcentration of perfluorooctanesulfonate in a partial life-cycle test with the fathead minnow (Pimephales promelas).
Ankley, Gerald T; Kuehl, Douglas W; Kahl, Michael D; Jensen, Kathleen M; Linnum, Ann; Leino, Richard L; Villeneuvet, Dan A
Perfluorooctanesulfonate (PFOS) is a widespread environmental contaminant emanating from the production and/or metabolism of fluorinated chemicals with a variety of applications. The goal of this work was to assess the toxicity and bioconcentration of PFOS in the fathead minnow (Pimephales promelas). Sexually mature fish were exposed via the water for 21 d to 0 (control), 0.03, 0.1, 0.3, or 1 mg PFOS/L, and effects on reproductive capacity and endocrinology were assessed. To determine possible developmental effects, a subset of embryos from parental exposures at each test concentration were held for an additional 24 d in the same PFOS treatments. A concentration of I mg PFOS/L was lethal to adults within two weeks. The 21-d 50% effect concentration (95% confidence interval) for effects on fecundity of the fish was 0.23 (0.19-0.25) mg PFOS/L. Exposure to PFOS caused various histopathological alterations, most prominently in ovaries of adult females. Adult males exposed to 0.3 mg PFOS/L for 21 d exhibited decreased aromatase activity and elevated concentrations of plasma 11-ketotestosterone and testosterone. No significant adverse effects on survival or growth were observed in developing fathead minnows held for 24 d at PFOS concentrations up to 0.3 mg/L. Adult fathead minnows readily accumulated PFOS from the water. The largest concentrations of PFOS were in blood, followed by liver and then gonad; for all tissues, females accumulated higher concentrations than males. Water and tissue concentrations of PFOS associated with effects in this study exceeded those reported for samples collected from the field by two to three orders of magnitude, suggesting that the current risk of PFOS on aspects of fish reproduction and development assessed in this study would be small. PMID:16193761
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
2. DETAIL VIEW OF ON RIGHT FOREGROUND FIXED SPAN TO TRANSITIONAL MOVEABLE SPAN TO FLOATING SPAN IN MIDDLEGROUND - Lacey V. Murrow Memorial Floating Bridge, Spanning Lake Washington at I-90, Seattle, King County, WA
Reproduction in the space environment: Part I. Animal reproductive studies
NASA Technical Reports Server (NTRS)
Santy, P. A.; Jennings, R. T.; Craigie, D.
Mankind's exploration and colonization of the frontier of space will ultimately depend on men's and women's ability to live, work, and reproduce in the space environment. This paper reviews animal studies, from microorganisms to mammals, done in space or under space-simulated conditions, which identify some of the key areas which might interfere with human reproductive physiology and/or embryonic development. Those space environmental factors which impacted almost all species included: microgravity, artificial gravity, radiation, and closed life support systems. These factors may act independently and in combination to produce their effects. To date, there have been no studies which have looked at the entire process of reproduction in any animal species. This type of investigation will be critical in understanding and preventing the problems which will affect human reproduction. Part II will discuss these problems directly as they relate to human physiology.
A spanning set for VOA modules
Geoffrey Buhl
We develop a spanning set for weak modules of C_2 co-finite vertex operator algebras. This spanning set has finiteness properties that we use to show weak modules are C_n co-finite and A_n(M) is finite dimensional.
From spanning forests to edge subsets
Trinks, Martin
We give some insight into Tutte's definition of internally and externally active edges for spanning forests. Namely we prove, that every edge subset can be constructed from the edges of exactly one spanning forest by deleting a unique subset of the internally active edges and adding a unique subset of the externally active edges.
Evolution of senescence in nature: physiological evolution in populations of garter snake with divergent life histories.
Robert, Kylie A; Bronikowski, Anne M
Evolutionary theories of aging are linked to life-history theory in that age-specific schedules of reproduction and survival determine the trajectory of age-specific mutation/selection balances across the life span and thus the rate of senescence. This is predicted to manifest at the organismal level in the evolution of energy allocation strategies of investing in somatic maintenance and robust stress responses in less hazardous environments in exchange for energy spent on growth and reproduction. Here we report experiments from long-studied populations of western terrestrial garter snakes (Thamnophis elegans) that reside in low and high extrinsic mortality environments, with evolved long and short life spans, respectively. Laboratory common-environment colonies of these two ecotypes were tested for a suite of physiological traits after control and stressed gestations. In offspring derived from control and corticosterone-treated dams, we measured resting metabolism; mitochondrial oxygen consumption, ATP and free radical production rates; and erythrocyte DNA damage and repair ability. We evaluated whether these aging biomarkers mirrored the evolution of life span and whether they were sensitive to stress. Neonates from the long-lived ecotype (1) were smaller, (2) consumed equal amounts of oxygen when corrected for body mass, (3) had DNA that damaged more readily but repaired more efficiently, and (4) had more efficient mitochondria and more efficient cellular antioxidant defenses than short-lived snakes. Many ecotype differences were enhanced in offspring derived from stress-treated dams, which supports the conclusion that nongenetic maternal effects may further impact the cellular stress defenses of offspring. Our findings reveal that physiological evolution underpins reptilian life histories and sheds light on the connectedness between stress response and aging pathways in wild-dwelling organisms. PMID:20050804
Reproductive allocation and output in herbaceous annuals of the genera Polygonum, Ipomoea, and Cassia in elevated CO[sub 2] environments
Farnsworth, E.J.; Bazzaz, F.A. (Harvard Univ., Cambridge, MA (United States))
In assessing the capacity of plants to adapt to rapidly changing global climate, we must elucidate the impacts of elevated carbon dioxide on reproduction, fitness and evolution. We investigated how elevated CO[sub 2] influenced reproduction and growth of plants exhibiting a range of floral displays, the implications of shifts in allocation for fitness in these species, and whether related taxa would show similar patterns of response. Three herbaceous, annual species each of the genera Polygonum, Ipomoea, and Cassia were grown under 350 or 700 ppm CO[sub 2]. Vegetative growth and reproductive output were non-destructively measured throughout the full life span, and biomass calibrated with a subsample harvest at first flowering. Viability and germination studies of seed progeny were conducted to more precisely characterize fitness. Timecourse and numbers of floral buds, flowers, unripe and abscised fruits differed between CO[sub 2] treatments. Genera differed significantly in their phenological responses to elevated CO[sub 2], Polygonum and Cassia species (but not Ipomoea) showed accelerated, enhanced reproduction. Elevated CO[sub 2] ameliorated trade-offs between vegetative and floral production. However, seed [open quotes]quality[close quotes] and fitness were not always directly correlated with quantity produced. Species within general responded more consistently to CO[sub 2], indicating that phylogeny and life form may be general predictors of performance under global change.
NSDL National Science Digital Library
Lisa D. Chong (the American Association for the Advancement of Science; Associate Editor of Science's STKE and Associate Editor of Science REV)
Animal development starts with fertilization, the fusion of a sperm and egg to create a viable embryo. The continuity of life then rests on successful embryogenesis and subsequent development of sexually mature organisms that can produce more sperm and eggs.
Reproductive success, early life stage development, and survival of westslope cutthroat trout (Oncorhynchus clarki lewisi) exposed to elevated selenium in an area of active coal mining
Barri-Lynn Rudolph; Iisak Andreller; Christopher J. Kennedy [Simon Fraser University, Burnaby, BC (Canada). Department of Biological Sciences
The effects of accumulated Se on the reproductive success and larval development of cutthroat trout (Oncorhynchus clarki lewisi) collected from a site of active coal mining in British Columbia were assessed. Eggs from 12 fish from an exposed site (Clode Pond) and 16 from a reference site (O'Rourke Lake) were field-collected and reared in the laboratory. Egg Se concentrations ranged from 12.3 to 16.7 and 11.8 to 140.0 {mu}g/g dry weight (dw) from fish collected at the reference and exposed sites, respectively. Other studies, including those with this species, have not shown Se to affect egg viability. However, in the present study, eggs with Se concentrations >86.3 {mu}g/g dw were not successfully fertilized or were nonviable at fertilization, while eggs with concentrations >46.8 and <75.4 {mu}g/g dw were fertilized (96% reached the eyed stage) but did not produce viable fry. A significant positive relationship between egg Se concentration and alevin mortality was observed. Deformities were analyzed in surviving fry which developed from eggs with Se concentrations between 11.8 and 20.6 {mu}g/g dw. No relationship between Se concentration in eggs and deformities or edema was found in this range, suggesting that the no-effect threshold for deformity is >20.6 {mu}g/g dw. The present data, in conjunction with the data from several other studies in temperate fish, suggest that current Se thresholds are conservative for cold-water fish. 25 refs., 3 figs.
[The Professor Luis Cerqueira Center for Psycho-Social Care Photocopier Project: from the reproduction of things to a productive life].
e Silva, Ana Luisa; da Fonseca, Rosa Maria
This study was born out of the necessity manifested by a portion of the population which uses the mental health service linked to the process of production of materialistic life through work. The intention was to comprehend the significance of work using historical and dialectic materialism as a reference, based upon the concepts of psycosocial rehabilitation and was performed through the analysis of discourses of the users. The site is the Prof. Luis Cerqueira Center for Psyco-Social Care (CAPS). The results evidence the comprehension of work as an instrument which enabled the users access to the field of social rights. PMID:12876848
Faster generation of random spanning trees
Kelner, Jonathan Adam
In this paper, we set forth a new algorithm for generating approximately uniformly random spanning trees in undirected graphs. We show how to sample from a distribution that is within a multiplicative (1+ d) of uniform in ...
Spanning tree generating functions and Mahler measures
Anthony J. Guttmann; Mathew D. Rogers
We define the notion of a spanning tree generating function (STGF) $\\sum a_n z^n$, which gives the spanning tree constant when evaluated at $z=1,$ and gives the lattice Green function (LGF) when differentiated. By making use of known results for logarithmic Mahler measures of certain Laurent polynomials, and proving new results, we express the STGFs as hypergeometric functions for all regular two and three dimensional lattices (and one higher-dimensional lattice). This gives closed form expressions for the spanning tree constants for all such lattices, which were previously largely unknown in all but one three-dimensional case. We show for all lattices that these can also be represented as Dirichlet $L$-series. Making the connection between spanning tree generating functions and lattice Green functions produces integral identities and hypergeometric connections, some of which appear to be new.
Wind effect on long span bridge
Zhang, Xi, M. Eng. Massachusetts Institute of Technology
This thesis has studied different types of reactions of long span bridge under wind load, such as vortex shedding, flutter and buffeting. Since all of these conditions have the chance to damage bridge structure, we calculate ...
Dispersal-related life-history trade-offs in a butterfly metapopulation.
Hanski, Ilkka; Saastamoinen, Marjo; Ovaskainen, Otso
1. Recent studies on butterflies have documented apparent evolutionary changes in dispersal rate in response to climate change and habitat change. These studies often assume a trade-off between dispersal rate (or flight capacity) and reproduction, which is the rule in wing-dimorphic species but might not occur equally in wing-monomorphic species such as butterflies. 2. To investigate the relationship between dispersal rate and fecundity in the Glanville fritillary butterfly Melitaea cinxia we recorded lifetime individual movements, matings, ovipositions, and maximal life span in a large (32 x 26 m) population cage in the field. Experimental material was obtained from 20 newly established and 20 old local populations within a large metapopulation in the Aland Islands in Finland. 3. Females of the Glanville fritillary from newly established populations are known to be more dispersive in the field, and in the cage they showed significantly greater mobility, mated earlier, and laid more egg clutches than females from old populations. The dispersive females from new populations exhibited no reduced lifetime fecundity in the cage, but they had a shorter maximal life span than old-population females. 4. These results challenge the dispersal-fecundity trade-off for nonmigratory butterflies but instead suggest a physiological trade-off between high metabolic performance and reduced maximal life span. High metabolic performance may explain high rates of dispersal and oviposition in early life. 5. In fragmented landscapes, an ecological trade-off exists between being more dispersive and hence spending more time in the landscape matrix vs. having more time for reproduction in the habitat. We estimate with a dispersal model parameterized for the Glanville fritillary that the lifetime egg production is 4% smaller on average in the more dispersive butterflies in a representative landscape, with much variation depending on landscape structure in the neighbourhood of the natal patch, from--26 to 45% in the landscape analysed in this paper. PMID:16903046
An Optimal Tone Reproduction Curve Operator for the Display of High Dynamic Range Images
Aickelin, Uwe
An Optimal Tone Reproduction Curve Operator for the Display of High Dynamic Range Images Guoping and digital imaging are to develop systems that match or maybe even exceed the capabilities of the human adaptation. Ordinary imaging sensors and reproduction media typically have dynamic ranges spanning a few
To subjugate NPY is to improve the quality of life and live longer.
Kalra, Satya P; Kalra, Pushpa S
The interactive network of neuropeptide Y (NPY) and cohorts is necessary for integrating the hypothalamic regulation of appetite and energy expenditure with the endocrine and neuroendocrine systems on a daily basis. Genetic and environmental factors that produce an insufficiency of leptin restraint on NPY and cognate receptors deregulate the homeostasis to engender various life-threatening risk factors. Recent studies from our laboratory show that neurotherapy consisting of a single central administration of recombinant adeno-associated virus vector encoding the leptin gene can repress the hypothalamic NPY system for the lifetime of rodents. A major benefit of this stable tonic restraint is deceleration of pathophysiologic sequalae that shorten life span. These include suppression of weight gain, fat accumulation, circulating adipokines, amelioration of major symptoms of metabolic syndrome, improved reproduction and bone health. Thus, sustained repression of NPY signaling in the hypothalamus by leptin transgene expression can improve the quality of life and extend longevity. PMID:17215061
NSDL National Science Digital Library
National Science Teachers Association (NSTA)
As older students enter the prepubescent years, they start to ask complex and sometimes sensitive questions. How does the egg become an organism? Do plants reproduce the same way as animals? Teaching about reproduction and heredity in these years is important since inaccuracies and misconceptions are easily developed. Whether you are teaching elementary students about characteristics and life cycles, or middle school students about reproduction and heredity, this web guide is an excellent resource for locating some of the best web sites to help develop student understanding from kindergarten through eighth grade. This web guide has multiple sites to help students and teachers develop an understanding of themes. Some sites are interactive and allow for student exploration into a deeper understanding of the theme. Others are good for core content, career information, or data sources. Use the icons associated with each site to select those that will meet your instructional needs. If you are looking for something specific, such as assessment, you can use the icons at the top as a filter to help you locate the resources you need. The content contained here also reminds teachers of the sensitive issues that arise when investigating human pedigrees, and offers alternative investigations into all characteristics -- whether genetic or environmental.
Modelling reproduction in farm animals: a review.
Blanc, F; Martin, G B; Bocquier, F
During the last few decades, our knowledge of the biology of the reproductive system has improved significantly and also become more quantitative. In parallel, there has been an increase in the development of mathematical models, as both research tools and management tools, that can integrate our knowledge of reproductive events and then attempt to predict reproductive efficiency. This review considers these modelling approaches according to the level of organization that they address, from representation of the dynamic functions of the reproductive axis to the prediction of reproductive performance of a flock or herd. We emphasize the contribution of modelling to the exploration and understanding of a complex system-a system that responds to a host of internal regulatory mechanisms as well as to an array of external factors such as nutrition, photoperiod and sociosexual signals. To date, models have proven useful for depicting the kinetics of some of the endocrine signals that are implicated in perturbations of the reproductive axis and they have also been successful in the exploration of ovarian dynamics during the oestrous cycle. However, two areas are still largely unexplored by biomathematical models: the dynamic links between the different stages of the reproductive life of an animal, and mechanistic influences of environmental factors on the reproductive axis. PMID:11833929
Component Analysis of Simple Span vs. Complex Span Adaptive Working Memory Exercises: A Randomized, Controlled Trial
Gibson, Bradley S.; Kronenberger, William G.; Gondoli, Dawn M.; Johnson, Ann C.; Morrissey, Rebecca A.; Steeger, Christine M.
There has been growing interest in using adaptive training interventions such as Cogmed-RM to increase the capacity of working memory (WM), but this intervention may not be optimally designed. For instance, Cogmed-RM can target the primary memory (PM) component of WM capacity, but not the secondary memory (SM) component. The present study hypothesized that Cogmed-RM does not target SM capacity because the simple span exercises it uses may not cause a sufficient amount of information to be lost from PM during training. To investigate, we randomly assigned participants to either a standard (simple span; N = 31) or a modified (complex span; N = 30) training condition. The main findings showed that SM capacity did not improve, even in the modified training condition. Hence, the potency of span-based WM interventions cannot be increased simply by converting simple span exercises into complex span exercises. PMID:23066524
Hominin life history: reconstruction and evolution
Shannen L. Robson; Bernard Wood
In this review we attempt to reconstruct the evolutionary history of hominin life history from extant and fossil evidence. We utilize demographic life history theory and distinguish life history variables, traits such as weaning, age at sexual maturity, and life span, from life history-related variables such as body mass, brain growth, and dental development. The latter are either linked with,
Male eastern bluebirds trade future ornamentation for current reproductive investment
Lynn Siefferman; Geoffrey E. Hill
Life-history theory proposes that organisms must trade-off investment in current and future reproduction. Production of ornamental display is an important component of reproductive effort that has rarely been considered in tests of allocation trade-offs. Male eastern bluebirds (Sialia sialis) display brilliant ultraviolet-blue plumage that is correlated with mate acquisition and male competitive ability. To investigate trade-offs between current reproductive effort
Life-long in vivo cell-lineage tracing shows that no oogenesis originates from putative germline stem cells in adult mice
Zhang, Hua; Liu, Lian; Li, Xin; Busayavalasa, Kiran; Shen, Yan; Hovatta, Outi; Gustafsson, Jan-┼ke; Liu, Kui
Whether or not oocyte regeneration occurs in adult life has been the subject of much debate. In this study, we have traced germ-cell lineages over the life spans of three genetically modified mouse models and provide direct evidence that oogenesis does not originate from any germline stem cells (GSCs) in adult mice. By selective ablation of all existing oocytes in a Gdf9-Cre;iDTR mouse model, we have demonstrated that no new germ cells were ever regenerated under pathological conditions. By in vivo tracing of oocytes and follicles in the Sohlh1-CreERT2;R26R and Foxl2-CreERT2;mT/mG mouse models, respectively, we have shown that the initial pool of oocytes is the only source of germ cells throughout the life span of the mice and that no adult oogenesis ever occurs under physiological conditions. Our findings clearly show that there are no GSCs that contribute to adult oogenesis in mice and that the initial pool of oocytes formed in early life is the only source of germ cells throughout the entire reproductive life span. PMID:25453063
34. Detail of movable span showing center structural tie between ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
34. Detail of movable span showing center structural tie between east and west spans centered over turning mechanism. VIEW SOUTHWEST - Broadway Bridge, Spanning Foundry Street, MBTA Yard, Fort Point Channel, & Lehigh Street, Boston, Suffolk County, MA
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
10. DETAIL, SOUTHEAST SPAN THROUGH CANAL, VIEW BLOCKED BY STEEL, CLAD COUNTER WEIGHT, WATER SPAN RAISED OUT OF VIEW - Cape Cod Canal Lift Bridge, Spanning Cape Cod Canal, Buzzards Bay, Barnstable County, MA
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
12. DETAIL OF UNDERSIDE OF NORTH APPROACH SPANS, SHOWING ROADWAY DECK AND APPROACH SPAN PIERS. VIEW TO SOUTHEAST. - Navajo Bridge, Spanning Colorado River at U.S. Highway 89 Alternate, Page, Coconino County, AZ
47. DRAW SPAN OVER PASSAIC RIVER Drawing No. 54 General ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
47. DRAW SPAN OVER PASSAIC RIVER Drawing No. 54 General Details of Wedge Operating Machinery for Draw Span Scale 1-1/2'=1'; April 1897 - Jackson Street Bridge, Spanning Passaic River, Newark, Essex County, NJ
Poetry and <span class="hlt">Literature (Library of Congress)
Site Title Here Library of Congress Ask a Librarian Digital Collections Library Catalogs <span class="hlt">Search GO The Library of Congress > Poetry & <span class="hlt">Literature Poetry and <span class="hlt">Literature Poetry and...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
2. THREE-QUARTER VIEW FROM ADJACENT ACCESS ROAD SHOWING THREE SPANS AND NORTHWEST APPROACH SPANS, LOOKING SOUTHEAST - Red River Bridge, Spanning Red River at U.S. Highway 82, Garland, Miller County, AR
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
40. UNDERSIDE OF TOWN CREEK SPAN (LEFT) AND PEARMAN BRIDE (RIGHT) FROM BENEATH BRIDGES, FACING EAST TOWARDS COOPER RIVER SPAN - Grace Memorial Bridge, U.S. Highway 17 spanning Cooper River & Town Creek , Charleston, Charleston County, SC
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
41. OBLIQUE VIEW OF NORTH SIDE OF COOPER RIVER SPAN WITH PEARMAN BRIDGE AND TOWN CREEK SPAN IN BACKGROUND, VIEW WEST TOWARDS CHARLESTON - Grace Memorial Bridge, U.S. Highway 17 spanning Cooper River & Town Creek , Charleston, Charleston County, SC
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
42. SOUTH SIDE OF COOPER RIVER SPAN WITH PEARMAN BRIDGE IN FOREGROUN, VIEW NORTHWEST TOWARDS TWIN CREEK SPAN AND DRUM ISLAND - Grace Memorial Bridge, U.S. Highway 17 spanning Cooper River & Town Creek , Charleston, Charleston County, SC
General closeup view of the swing span bridge in the ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
General close-up view of the swing span bridge in the close position, looking upriver. The pivot/center pier is positioned in the center of Tennessee River. Note: Each arm of the continuous swing span acts as simple spans. The total span over four (4) supports is partially continuous-- the middle panel at the center pier is continuous for bending moments, but discontinuous for shears. - Bridgeport Swing Span Bridge, Spanning Tennessee River, Bridgeport, Jackson County, AL
The effect of long non-reproductive periods on the genital health in captive female white rhinoceroses (Ceratotherium simum simum, C.s. cottoni).
Hermes, Robert; Hildebrandt, Thomas Bernd; Walzer, Christian; G÷ritz, Frank; Patton, Marilyn L; Silinski, Sandra; Anderson, Matt J; Reid, Catherine E; Wibbelt, Gudrun; Tomasova, Kristina; Schwarzenberger, Franz
White rhinoceroses suffer from a low reproductive rate in captivity. Intensive efforts to propagate specifically the northern white rhinoceros have been very limited. The dismal outlook for this subspecies in the wild makes successful ex situ breeding programs paramount. In this context, this study examined 48 southern and 6 northern white rhinoceroses using ultrasound and faecal hormone analysis to elucidate causes for female reproductive failure and to determine whether long non-reproductive periods have a detrimental impact on genital health. Results showed that 76% of the nulliparous females had intact hymenal membrane indicating these females had never been bred, at an age when their wild counterparts have delivered multiple offspring. Fifty-six percent of the studied population had various reproductive pathology. Cystic endometrial hyperplasia; leiomyomas of the cervix, uterus and ovary, adenoma; para-ovarian cysts and hydromucometra represent the scope of lesions identified. The stages of the lesions in nulliparous females correlated with age (r = 0.4, P < 0.05). Due to the severity of the lesions, 28% of the study population was considered post-reproductive. Therefore, the reproductive life span in some individuals was 10-20 years shorter than expected. However, in parous females the incidence of pathological lesions was significantly lower (P < 0.0001). Seventy-eight percent females studied had erratic or absent luteal activity. The hormone data corresponded with two ultrasonographic levels of ovarian activity, active and inactive, occurring within an age range of 3-19 years and 15-38 years, respectively. This suggests the lack of ovarian activity by reproductive mid-life in non-reproducing females. The accuracy of the ultrasound findings was validated by necropsy in nine animals showing a strong positive correlation (r2 = 0.9, p < 0.001). Our data suggests that the development of reproductive pathology and ovarian inactivity in white rhinoceros is an age-related consequence of long non-reproductive periods. This asymmetric ageing process of the genital organs can be prevented with the achievement of at least one pregnancy. PMID:16213012
Are reproductive and somatic senescence coupled in humans? Late, but not early, reproduction correlated with longevity in historical Sami women
Helle, Samuli; Lummaa, Virpi; Jokela, Jukka
Evolutionary theory of senescence emphasizes the importance of intense selection on early reproduction owing to the declining force of natural selection with age that constrains lifespan. In humans, recent studies have, however, suggested that late-life mortality might be more closely related to late rather than early reproduction, although the role of late reproduction on fitness remains unclear. We examined the association between early and late reproduction with longevity in historical post-reproductive Sami women. We also estimated the strength of natural selection on early and late reproduction using path analysis, and the effect of reproductive timing on offspring survival to adulthood and maternal risk of dying at childbirth. We found that natural selection favoured both earlier start and later cessation of reproduction, and higher total fe cundity. Maternal age at childbirth was not related to offspring or maternal survival. Interestingly, females who produced their last offspring at advanced age also lived longest, while age at first reproduction and total fecundity were unrelated to female longevity. Our results thus suggest that reproductive and somatic senescence may have been coupled in these human populations, and that selection could have favoured late reproduction. We discuss alternative hypotheses for the mechanisms which might have promoted the association between late reproduction and longevity. PMID:15875567
Reproductive strategy, sexual development and attraction to facial characteristics
R. Elisabeth Cornwell; Miriam J. Law Smith; Lynda G. Boothroyd; Fhionna R. Moore; Hasker P. Davis; Michael Stirrat; Bernard Tiddeman; David I. Perrett
Sexual reproduction strategies vary both between and within species in the level of investment in offspring. Life-history theories suggest that the rate of sexual maturation is critically linked to reproductive strategy, with high investment being associated with few offspring and delayed maturation. For humans, age of puberty and age of first sex are two developmental milestones that have been associated
Reproductive effort in invasive and non-invasive Rubus
Susan C. McDowell; David P. Turner
We quantified the physiological costs and the total amount of resources allocated to reproduction in two closely related species of Rubus, one of which is invasive. These two species share several morphological and life-history characteristics and grow together in the Pacific Northwestern United States. Reproductive effort was manipulated in canes of both species by removing flower buds. The non-invasive species,
Of late, there is increasing recognition that exposures before, at or shortly after conception have life-long implications for human reproduction and development. Despite this evolving literature, few research initiatives have been designed to empirically evaluate exposures durin...
Teaching about September 11th and Its Aftermath. C-SPAN in the Classroom.
ERIC Educational Resources Information Center
C-SPAN, Washington, DC.
The events of and since September 11, 2001 have had an immeasurable impact on all facets of people's lives, especially in the United States. The loss of human life, threatened public safety, and the impact of a military response are just some of the issues concerning U.S. citizens and public officials. This C-SPAN in the Classroom series offersģ
Prospective Span as a Cognitive Ability
ERIC Educational Resources Information Center
Dickstein, Louis S.
From a sample of 51 male college students prospective span (PS) in TAT stories was related to two cognitive tasks requiring anticipation, Mazes Test and Seeing Deficiencies Test, but unrelated to Vocabulary and Information subtests of WAIS. PS was negatively related to academic grades. Reprints available from author, Department of Psychology,ģ
School Organization: Grade Span. Trends and Issues.
ERIC Educational Resources Information Center
Renchler, Ron
This paper examines grade spans (grade configurations) and their importance in community school systems. Research has shown that geographic location often dictates the kind of grade configuration districts use. Furthermore, every grade configuration has strengths and weaknesses, and school officials must focus on developing the positive potentialģ
Clustering, Community Partition and Disjoint Spanning Trees
Zhang, Cun-Quan "CQ"
35 Clustering, Community Partition and Disjoint Spanning Trees CUN-QUAN ZHANG AND YONGBIN OU West, dynamic density, hierarchical clustering ACM Reference Format: Zhang, C.-Q. and Ou, Y. 2008. Clustering. DOI = 10.1145/1367064.1367075 http://doi. acm.org/10.1145/1367064.1367075 C.-Q. Zhang was supported
Faster generation of random spanning trees
Jonathan A. Kelner; Aleksander Madry
In this paper, we set forth a new algorithm for generating approximately uniformly random spanning trees in undirected graphs. We show how to sample from a distribution that is within a multiplicative (1 + ) of uniform in expected time e O(m p n log 1= ). This improves the sparse graph case of the best previously known worst-case bound
Digit Span: Effect of education and culture
Asucena Lozano
The Digit Span test is one of the most commonly used measures of immediate verbal recall, attentional capacity, and working memory in neuropsychological research and clinical evaluations. This test comprises two modalities, digits forward and digits backward. It has been established that age, education, and culture are important variables that affect performance on this test. The purposes of this study
Spanning Multiaccess Channel Hypercube Computer Interconnection
Patrick W. Dowd; Kamal Jabbour
A distributed computer system based on a hypercube topology is proposed, where multiaccess channels spanning all dimensional axes provide processor interconnection. Demand assignment multiple access protocols are used to provide access arbitration. A highly fault tolerant system with excellent performance characteristics results, at a cost significantly lower than comparable structures.
Spanning multiaccess channel hypercube computer interconnection
Dowd, P.W.; Jabbour, K.
A distributed computer system based on a hypercube topology is proposed, where multiaccess channels spanning all dimensional axes provide processor interconnection. Demand assignment multiple access protocols are used to provide access arbitration. A highly fault tolerant system with excellent performance characteristics results, at a cost significantly lower than comparable structures.
Stitching: pen gestures that span multiple displays
Ken Hinckley; Gonzalo Ramos; Francois Guimbretiere; Patrick Baudisch; Marc Smith
Stitching is a new interaction technique that allows users to combine pen-operated mobile devices with wireless networking by using pen gestures that span multiple displays. To stitch, a user starts moving the pen on one screen, crosses over the bezel, and finishes the stroke on the screen of a nearby device. Properties of each portion of the pen stroke are
Balanced Trade-Offs between Alternative Strategies Shape the Response of C. elegans Reproduction to
Ruvinsky, Ilya
laying, and thus protecting the reproductive system, is negated by the cost associated with implementing-offs as a dynamic response of the C. elegans reproductive system to stress and an adaptation to life in variableBalanced Trade-Offs between Alternative Strategies Shape the Response of C. elegans Reproduction
... NICHD Research Information Clinical Trials Resources and Publications Men's Reproductive Health: Overview Skip sharing on social media ... Content Reproductive health is an important component of men's overall health and well-being. Too often, males ...
The male reproductive system, like that of the female, consists of those organs whose function is to produce a new individual, i.e., to accomplish reproduction. This system consists of a pair of testes and a ...
A Novel Quantitative Approach to WomenÆs Reproductive Strategies
Milne, Fritha H.; Judge, Debra S.
The patterned way in which individuals allocate finite resources to various components of reproduction (e.g. mating effort, reproductive timing and parental investment) is described as a reproductive strategy. As energy is limited, trade-offs between and within aspects of reproductive strategies are expected. The first aim of this study was to derive aspects of reproductive strategies using complete reproductive histories from 718 parous Western Australian women. Factor analysis using a subset of these participants resulted in six factors that represented æshort-term mating strategyÆ, æearly onset of sexual activityÆ, æreproductive outputÆ, ætiming of childbearingÆ, æbreastfeedingÆ, and æchild spacingÆ. This factor structure was internally validated by replication using a second independent subset of the data. The second aim of this study examined trade-offs between aspects of reproductive strategies derived from aim one. Factor scores calculated for each woman were incorporated in generalised linear models and interaction terms were employed to examine the effect of mating behaviour on the relationships between reproductive timing, parental investment and overall reproductive success. Early sexual activity correlates with early reproductive onset for women displaying more long-term mating strategies. Women with more short-term mating strategies exhibit a trade-off between child quantity and child quality not observed in women with a long-term mating strategy. However, women with a short-term mating strategy who delay reproductive timing exhibit levels of parental investment (measured as breastfeeding duration per child) similar to that of women with long-term mating strategies. Reproductive delay has fitness costs (fewer births) for women displaying more short-term mating strategies. We provide empirical evidence that reproductive histories of contemporary women reflect aspects of reproductive strategies, and associations between these strategic elements, as predicted from life history theory. PMID:23056440
Ethical challenges in reproductive medicine: posthumous reproduction
G Bahadur
Introduction: New technologies in the field of reproductive medicine have given rise to new possibilities for the application of this technology. These possibilities have in turn led to new ethical and policy dilemmas. This paper discusses the complex moral, ethical and legal concerns that posthumous assisted reproduction (PAR) gives rise to: questions such as what constitutes informed consent, and whether
Effects of Bartonella spp. on Flea Feeding and Reproductive Performance
Morick, Danny; Krasnov, Boris R.; Khokhlova, Irina S.; Gutiķrrez, Ricardo; Fielden, Laura J.; Gottlieb, Yuval
Numerous pathogens are transmitted from one host to another by hematophagous insect vectors. The interactions between a vector-borne organism and its vector vary in many ways, most of which are yet to be explored and identified. These interactions may play a role in the dynamics of the infection cycle. One way to evaluate these interactions is by studying the effects of the tested organism on the vector. In this study, we tested the effects of infection with Bartonella species on fitness-related variables of fleas by using Bartonella sp. strain OE 1-1, Xenopsylla ramesis fleas, and Meriones crassus jirds as a model system. Feeding parameters, including blood meal size and metabolic rate during digestion, as well as reproductive parameters, including fecundity, fertility, and life span, were compared between fleas experimentally infected with Bartonella and uninfected fleas. In addition, the developmental time, sex ratio, and body size of F1 offspring fleas were compared between the two groups. Most tested parameters did not differ between infected and uninfected fleas. However, F1 males produced by Bartonella-positive females were significantly smaller than F1 males produced by Bartonella-negative female fleas. The findings in this study suggest that bartonellae are well adapted to their flea vectors, and by minimally affecting their fitness they have evolved to better spread themselves in the natural environment. PMID:23542614
Detail of center of swing span rotation. Forty (40) rods ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
Detail of center of swing span rotation. Forty (40) rods radiate out from a center cap stand (like spokes on a bicycle) and hold 40 20-inch diameter wheels onto a rim bearing circular track on which they roll when swing span is opened and closed. - Bridgeport Swing Span Bridge, Spanning Tennessee River, Bridgeport, Jackson County, AL
Hierarchical Minimum Spanning Trees for Lossy Image Set Compression
Cheng, Howard
tree is significantly lower than the previous minimum spanning tree algorithms. 1 Introduction spanning tree algorithms have been proposed for the lossy compression of image sets. In these algorithms spanning tree algorithm in which the minimum spanning tree algorithm is first applied to clusters
[Gender approach to studying reproductive aims in young people].
Radchenko, O R
The paper presents the preliminary results of estimating reproductive potential in young people. Gender characteristics have been revealed in the sexual behavior (the young men start a sexual life at significantly earlier age; different attitudes towards contraception) and reproductive aims (children rank fourth among family values; a low proportion of persons who wish to have two children or more) of the youth in the Republic of Tatarstan. Certain risk factors influencing reproductive health impairments are identified. Differential forms of prophylactic work, which are aimed at promoting reproductive health for young people, are proposed. PMID:21899107
Sex, attachment, and the development of reproductive
Maestripieri, Dario
strategies, thus contributing to a coherent evolutionary theory of human development. Keywords: adrenarche plasticity, reproductive strategies, sexual selection, stress 1. Introduction 1.1. Aim and scope investment theory, and sexual selection; it aims to provide a significant update to current life history
The ethics of assisted reproduction.
Chatzinikolaou, Nikolaos
Issues concerning the beginning of life and medical intervention in the onset of human existence are very delicate in their nature; they involve multi-dimensional knowledge, they are difficult to comprehend and sensitive to handle. When pure scientific elements are combined with profound emotions, when the genius of technological discoveries touches upon human dignity and sanctity, when passion for the technological achievement intervenes in basic human rights, then the sense of inadequacy and ignorance becomes intense and critical. Silence seems more sought-after than words, and willingness to learn more prudent than the desire to speak. Fear of the inconceivable consequences and even more so the inability to assess them, experiments with the unknown, the likelihood that basic historical, ethical and social values may change forever, but mainly the replacement of God in His wondrous work of creation--the onset of human life--places the ethics of reproductive technologies on the frontline of contemporary bioethics. This opinion paper does not deal with dangers, insults, fears, threats, "speed limits" or ethical controversies, but rather with the very mystery of life. Although there are no generally accepted replies to the various questions being posed, some thoughts and reservations, which can shed some light upon complicated dilemmas are presented. Firstly, the content of reproductive technologies, the problem of infertility today, the methods of fertility treatment, and of prenatal and pre-implantation testing are described, and then the social impact of IVF, complicated cases, deontological dilemmas and some ethical concerns are discussed. PMID:20412986
An Airfoil Spanning an Open Jet
NASA Technical Reports Server (NTRS)
Stuper, J
Proceeding from the fundamental problem on the mutual relation of a wing and free boundaries the distribution of the circulation is determined for an airfoil spanning an open jet of rectangular section at different aspect ratios, and then for an open jet of circular section. The solution is obtained by means of a Fourier series and computations have been performed for different values of the variables. The second part describes the experiments performed for the purpose of proving the theory. The results confirm the theory. In conclusion it defines the induced drag of a wing extending across an open jet and compares it with the drag of a monoplane having a span equal to the jet width at equal total lift.
Optimal decomposable witnesses without the spanning property
Augusiak, Remigiusz [ICFO-Institut de Ciencies Fotoniques, E-08860 Castelldefels (Barcelona) (Spain); Sarbicki, Gniewomir [Insitute of Physics, Nicolaus Copernicus University, Grudzicdzka 5, PL-87-100 Torun (Poland); Lewenstein, Maciej [ICFO-Institut de Ciencies Fotoniques, E-08860 Castelldefels (Barcelona) (Spain); ICREA-Institucio Catalana de Recerca i Estudis Avancats, Lluis Companys 23, E-08010 Barcelona (Spain)
One of the unsolved problems in the characterization of the optimal entanglement witnesses is the existence of optimal witnesses acting on bipartite Hilbert spaces H{sub m,n}=C{sup m} x C{sup n} such that the product vectors obeying
Age, growth, and reproductive biology of three catostomids from the Apalachicola River, Florida
Grabowski, Timothy B.; Young, S.P.; Isely, J.J.; Ely, Patrick C.
Riverine catostomids can show a wide range of interspecific variation in life-history characteristics. Understanding these differences is an important consideration in evaluating the sensitivity of these fishes to disturbance and in formulating effective conservation strategies, particularly when dealing with an assemblage consisting of multiple species within a watershed. We collected Apalachicola redhorse Moxostoma n. sp. cf. poecilurum (n = 125), spotted sucker Minytrema melanops (n = 94), and quillback Carpiodes cyprinus (n = 94) to determine age, growth, and reproductive biology of spawning catostomids in the Apalachicola River, Florida, during 2007. Quillback was the smallest in total length at age; longest-lived; most fecund; and produced the smallest eggs. Apalachicola redhorse was the largest in body size; had an intermediate life span; and produced the fewest yet largest eggs. Spotted sucker was more similar to Apalachicola redhorse in most characteristics. Growth during ages 1-3 in all three species seemed to be negatively related to the proportion of observations of extreme flow, both high (Q90) and low (Q10), per year and a positive response in growth rate to high flows (>Q75 but < Q90). However, Apalachicola redhorse and spotted sucker growth was more sensitive to flow conditions than that of quillback. Our results suggest the life histories and ecological response of Apalachicola River catostomids to flow regulation are important components for developing strategies that incorporate the needs of these fishery resources into an ecosystem-based management approach.
Low cost of reproduction in female stalk-eyed flies, Cyrtodiopsis dalmanni.
Reguera, Piedad; Pomiankowski, Andrew; Fowler, Kevin; Chapman, Tracey
We investigated the effect of exposure to males on female longevity and egg production in the stalk-eyed fly, Cyrtodiopsis dalmanni. In this species, females typically mate several times each morning over a lifetime that can span several months. We hypothesised that high costs of mating with males would be incompatible with the life history of this species. We predicted that 1) female longevity costs of exposure to males would be low, and 2) that the magnitude of mating-induced fecundity increases in C. dalmanni, if present, would also be low. We tested the predictions by comparing the longevity and lifetime fecundity of virgin and mated females. In line with prediction 1), the longevity difference between virgin and fully reproductive females was small and of borderline significance. In line with prediction 2), egg production was not significantly higher in females continually exposed to males than for virgin females. Our results suggest that costs of reproduction resulting from exposure to males are low in species that mate promiscuously at high rates. PMID:15037098
Does it pay to delay? Flesh flies show adaptive plasticity in reproductive timing
Frank J. Wessels; Ross Kristal; Fleta Netter; John D. Hatle; Daniel A. Hahn
Life-history plasticity is widespread among organisms. However, an important question is whether it is adaptive. Most models\\u000a for plasticity in life-history timing predict that animals, once they have reached the minimal nutritional threshold under\\u000a poor conditions, will accelerate development or time to reproduction. Adaptive delays in reproduction are not common, especially\\u000a in short-lived species. Examples of adaptive reproductive delays exist
Male Reproductive Health and Prostate Cancer Risk
Walsh, Thomas J.
Purpose of review Male infertility impacts a substantial proportion of men and has serious implication for a manÆs quality of life. Advances in reproductive technology may allow men to bypass urologic care in order to achieve their family planning goals. Recent data suggests that male reproductive failure may be a harbinger of future urologic diseases, including prostate cancer, thus emphasizing the importance of dedicated urologic evaluation and care for all male infertility patients. Recent findings We will review the epidemiologic data that explores an association between male reproductive health and prostate cancer. We will review the potential biologic mechanisms that may underlie this association, and explore possible reasons for inconsistencies in study findings. Summary Studies of the association between male infertility and prostate cancer are inconsistent. Despite this, the association between reproductive health in a manÆs fourth decade (30s) and his development of aggressive prostate cancer in his sixth decade (50s) should not be ignored. These findings, combined with the robustness of the potential common underlying mechanisms, provide a foundation for future studies of male reproductive health that are more specific and directed in their approach to answering questions about the association between male reproductive failure and future systemic disease. PMID:21941182
Reproduction (II): Human Control of Reproductive Processes
ERIC Educational Resources Information Center
Jost, Alfred
Describes methods of intervening in reproduction of animals and humans (artificial insemination, contraception, ovular and blastodisc transplants, pre selection of sex, cloning) and discusses the social implications of their use with humans. (AL)
Persistent organic pollutants and male reproductive health
Vested, Anne; Giwercman, Aleksander; Bonde, Jens Peter; Toft, Gunnar
Environmental contaminants such as persistent organic pollutants (POPs) are man-made bioaccumulative compounds with long half-lives that are found throughout the world as a result of heavy use in a variety of consumer products during the twentieth century. Wildlife and animal studies have long suggested adverse effects of exposure to these compounds on human reproductive health, which, according to the endocrine disrupter hypothesis, are ascribed to the compoundsÆ potential to interfere with endocrine signaling, especially when exposure occurs during certain phases of fetal and childhood development. An extensive number of epidemiological studies have addressed the possible effects of exposure to POPs on male reproductive health, but the results are conflicting. Thus far, most studies have focused on investigating exposure and the different reproductive health outcomes during adulthood. Some studies have addressed the potential harmful effects of fetal exposure with respect to malformations at birth and/or reproductive development, whereas only a few studies have been able to evaluate whether intrauterine exposure to POPs has long-term consequences for male reproductive health with measurable effects on semen quality markers and reproductive hormone levels in adulthood. Humans are not exposed to a single compound at a time, but rather, to a variety of different substances with potential divergent hormonal effects. Hence, how to best analyze epidemiological data on combined exposures remains a significant challenge. This review on POPs will focus on current knowledge regarding the potential effects of exposure to POPs during fetal and childhood life and during adulthood on male reproductive health, including a critical revision of the endocrine disruption hypothesis, a comment on pubertal development as part of reproductive development and a comment on how to account for combined exposures in epidemiological research. PMID:24369135
Pulsed resources and the coupling between life-history strategies and exploration patterns in eastern chipmunks (Tamias striatus).
Montiglio, Pierre-Olivier; Garant, Dany; Bergeron, Patrick; Messier, Gabrielle Dubuc; Rķale, Denis
Understanding the causes of animal personality (i.e. consistent behavioural differences) is a major aim of evolutionary studies. Recent theoretical work suggests that major personality traits may contribute to evolutionary trade-offs. However, such associations have only been investigated in a few study systems, and even less so in free ranging animal populations. Eastern chipmunks exhibit consistent individual differences in exploration, ranging from slow to fast. Birth cohorts also experience dramatic differences in age at first breeding opportunity due to annual differences in beech mast. Individuals may breed for the first time at 24, 33 or 50% of their average life span, depending on year of birth. Here, we used data from a long-term survey on a wild population to investigate the relationship between reproductive life history and consistent individual differences in exploration. We determined whether predictable differences in age at first breeding opportunity among birth cohorts were associated with exploration differences and favoured individuals with different exploration. Birth cohorts with a predictably earlier age at first breeding opportunity were faster explorers on average. Slower explorers displayed their highest fecundity (females) or highest fertilization success (males) later in their life compared with faster explorers. Overall, slow explorers attained a higher lifetime reproductive success than fast explorers when given an opportunity to reproduce later in their life. Our results suggest that the timing of mating seasons, associated with fluctuating food abundance, may favour individual variation in exploration and maintain population variation through its effects on reproductive life history. Together, our result shed light on how fluctuation in ecological conditions may maintain personality differences and on the nature of the relationships between animal personality and life history. PMID:24180283
Pycock, Jonathan
Jonathan Pycock is one of three equine claims consultants with the Veterinary Defence Society. His career in equine reproduction, and lecturing on the same topic, has given him the opportunity to work and travel widely, and ensure his work/life balance stays in sync. PMID:25748201
Obesity and Reproductive Function
Jungheim, Emily S.; Travieso, Jennifer L.; Carson, Kenneth R.; Moley, Kelle H.
SYNOPSIS Obesity is associated with multiple adverse reproductive outcomes, but the mechanisms involved are largely unknown. Public health scientists studying obesity and its effects on health outcomes have referred to obesity as a ōcomplex systemö, defined as a system of heterogeneous parts interacting in nonlinear ways to influence the behavior of the parts as a whole1,22. By this definition, human reproduction is also a complex system which may explain some of the difficulty in identifying the mechanisms linking obesity and adverse reproductive function. Despite the difficulties, research on obesity and reproduction is important as there is an epidemic of obesity among reproductive age women with associated consequences for future generations. In this review we discuss the adverse reproductive outcomes associated with obesity and data from translational studies of the mechanisms involved. We conclude with a brief discussion of public health policy as it relates to the treatment of infertility in obese women. PMID:23182555
Functional Linkages for the Pace of Life, Life-history, and Environment in Birds
Williams, Joseph B.; Miller, Richard A.; Harper, James M.; Wiersma, Popko
For vertebrates, body mass underlies much of the variation in metabolism, but among animals of the same body mass, metabolism varies six-fold. Understanding how natural selection can influence variation in metabolism remains a central focus of Physiological Ecologists. Life-history theory postulates that many physiological traits, such as metabolism, may be understood in terms of key maturational and reproductive characteristics over an organismÆs life-span. Although it is widely acknowledged that physiological processes serve as a foundation for life-history trade-offs, the physiological mechanisms that underlie the diversification of life-histories remain elusive. Data show that tropical birds have a reduced basal metabolism (BMR), field metabolic rate, and peak metabolic rate compared with temperate counterparts, results consistent with the idea that a low mortality, and therefore increased longevity, and low productivity is associated with low mass-specific metabolic rate. Mass-adjusted BMR of tropical and temperate birds was associated with survival rate, in accordance with the view that animals with a slow pace of life tend to have increased life spans. To understand the mechanisms responsible for a reduced rate of metabolism in tropical birds compared with temperate species, we summarized an unpublished study, based on data from the literature, on organ masses for both groups. Tropical birds had smaller hearts, kidneys, livers, and pectoral muscles than did temperate species of the same body size, but they had a relatively larger skeletal mass. Direct measurements of organ masses for tropical and temperate birds showed that the heart, kidneys, and lungs were significantly smaller in tropical birds, although sample sizes were small. Also from an ongoing study, we summarized results to date on connections between whole-organism metabolism in tropical and temperate birds and attributes of their dermal fibroblasts grown in cell culture. Cells derived from tropical birds had a slower rate of growth, consistent with the hypothesis that these cells have a slower metabolism. We found that dermal fibroblasts from tropical birds resisted chemical agents that induce oxidative and non-oxidative stress better than do cells from temperate species, consistent with the hypothesis that birds that live longer invest more in self-maintenance such as antioxidant properties of cells. PMID:21558245
Bubaline versus bovine reproduction.
Drost, M
Fertility in water buffalo (Bubalus bubalis) is considerably lower than that in cattle (Bos taurus and Bos indicus). Poor breeding efficiency is attributed to late onset of puberty, seasonality, poor estrus expression, and long calving intervals. Accurate estrus detection is a prerequisite for efficient reproductive management. Established reproductive management techniques in cattle can be successfully applied to water buffalo because of the similarities in the anatomy, physiology, and endocrinology of reproduction between the two genera. PMID:17482253
Computing Minimum Spanning Trees with Uncertainty
Erlebach, Thomas; Krizanc, Danny; Mihal'ßk, Mat·s; Raman, Rajeev
We consider the minimum spanning tree problem in a setting where information about the edge weights of the given graph is uncertain. Initially, for each edge $e$ of the graph only a set $A_e$, called an uncertainty area, that contains the actual edge weight $w_e$ is known. The algorithm can `update' $e$ to obtain the edge weight $w_e \\in A_e$. The task is to output the edge set of a minimum spanning tree after a minimum number of updates. An algorithm is $k$-update competitive if it makes at most $k$ times as many updates as the optimum. We present a 2-update competitive algorithm if all areas $A_e$ are open or trivial, which is the best possible among deterministic algorithms. The condition on the areas $A_e$ is to exclude degenerate inputs for which no constant update competitive algorithm can exist. Next, we consider a setting where the vertices of the graph correspond to points in Euclidean space and the weight of an edge is equal to the distance of its endpoints. The location of each point is initially g...
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INTERIOR OF WEST SPAN LOOKING WEST (SHADOW OF VERTICAL LAPS PLACED ON ZONE III; ASPHALT ZONE IX) - Honey Run Bridge, Spanning Butte Creek, bypassed section of Honey Run Road (originally Carr Hill Road), Paradise, Butte County, CA
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ELEVATION NORTHEAST BY 30 DEGREES, WEST SECTIONS OF SPAN COVERED BY OVERGROWTH - Honey Run Bridge, Spanning Butte Creek, bypassed section of Honey Run Road (originally Carr Hill Road), Paradise, Butte County, CA
Detail of expansion bearing shoe of Span No. 1 on ...
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Detail of expansion bearing shoe of Span No. 1 on Abutment No. 1, view to south - Gillespie Dam Bridge, Spanning Gila River on Old US 80 Highway, south of Gillespie Dam, Arlington, Maricopa County, AZ
52. Fixed Span, Top Chord at Panel Point 6; diagonal ...
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52. Fixed Span, Top Chord at Panel Point 6; diagonal member goes to intermediate connection 7 & then to bottom chord at 8; looking ESE. - Pacific Shortline Bridge, U.S. Route 20,spanning Missouri River, Sioux City, Woodbury County, IA
48. Fixed Span, Detail of Pinned Connection between End Post ...
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48. Fixed Span, Detail of Pinned Connection between End Post & First Segment of Top Chord (Vertical Tension Member goes to 2L); looking E. - Pacific Shortline Bridge, U.S. Route 20,spanning Missouri River, Sioux City, Woodbury County, IA
56. View below deck of Manhattan side span showing ramps ...
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56. View below deck of Manhattan side span showing ramps to East Side Expressway. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York, New York County, NY
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2. DETAIL VIEW OF MAIN (RIVER) SPAN VIEWED FROM NORTH BANK OF ILLINOIS RIVER, LOOKING SOUTHEAST. - Illinois Central Railroad, Illinois River Bridge, Spanning Illinois River, La Salle, La Salle County, IL
26. Southern approach span showing detail plan, elevation, and existing ...
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26. Southern approach span showing detail plan, elevation, and existing views for pier and abutment structural changes required after flood of December 1955. - Moody Bridge, Spanning South Fork Eel River, Garberville, Humboldt County, CA
21. Southern approach span plan and elevation views for pier ...
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21. Southern approach span plan and elevation views for pier and abutment structural changes required after flood of December 1955 on Moody Bridge. - Moody Bridge, Spanning South Fork Eel River, Garberville, Humboldt County, CA
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17. DETAIL OF FIRST NORTH APPROACH SPAN, SHOWING PIER, ENDPOST, UPPER AND LOWER CHORDS AND DIAGONALS. VIEW TO SOUTH. - Navajo Bridge, Spanning Colorado River at U.S. Highway 89 Alternate, Page, Coconino County, AZ
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14. DETAIL OF SECOND NORTH APPROACH SPAN, SHOWING STEEL PIERS AND CANTILEVERED CONCRETE PEDESTAL. VIEW TO SOUTH. - Navajo Bridge, Spanning Colorado River at U.S. Highway 89 Alternate, Page, Coconino County, AZ
9. Detail of east truss at center of span, showing ...
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9. Detail of east truss at center of span, showing upper chord connection to vertical and diagonal members, looking northeast - Tuttle Bridge, Spanning Housatonic River on Golden Hill Road, Lee, Berkshire County, MA
View of West end of central lift span truss web ...
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View of West end of central lift span truss web of Tensaw River Bridge, showing web brace of lift girder superstructure, looking west - Tensaw River Lift Bridge, Spanning Tensaw River at U.S. Highway 90, Mobile, Mobile County, AL
7. Detail of southwest corner of span from upper bridge, ...
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7. Detail of southwest corner of span from upper bridge, showing upper chord rivets and castings, looking downward and southeast - Lower Rollstone Street Bridge, Spanning Nashua River on Rollstone Street, Fitchburg, Worcester County, MA
32. Moving draw span from Ship Canal to University Heights ...
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32. Moving draw span from Ship Canal to University Heights Bridge. June 14, 1906 artist rendering - University Heights Bridge, Spanning Harlem River at 207th Street & West Harlem Road, New York, New York County, NY
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1. SUMMER STREET BRIDGE. DRAW SPAN MOVES TOWARD VIEWER ON TRACKS VISIBLE AT CENTER OF PHOTOGRAPH. - Summer Street Retractile Bridge, Spanning Fort Point Channel at Summer Street, Boston, Suffolk County, MA
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20. DETAIL VIEW OF MOVABLE SPAN MACHINERY UNDER GRID DECK AT CENTRAL CONCRETE SUPPORT PEDESTAL, SHOWING DRIVE GEARS, ELECTRIC MOTOR AND STEEL BEAMS (taken in January 1984) - Sharptown Bridge, Spanning Nanticoke River, State Route 313, Sharptown, Wicomico County, MD
8. General view of truss geometry at center of span ...
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8. General view of truss geometry at center of span from lower parking lot, looking northwest - Lower Rollstone Street Bridge, Spanning Nashua River on Rollstone Street, Fitchburg, Worcester County, MA
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11. DETAIL VIEW OF TRUSS, 1917 SPAN, SOUTHWEST ELEVATION, LOOKING NORTHEAST - Mystic River Drawbridge No. 7, Spanning Mystic River at Boston & Maine Railroad Eastern Route, Somerville, Middlesex County, MA
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9. FRONTAL VIEW OF MOVABLE SPANS, RAISED AND SUSPENDED IN OPENING OPERATION - Mystic River Drawbridge No. 7, Spanning Mystic River at Boston & Maine Railroad Eastern Route, Somerville, Middlesex County, MA
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CLOSE-UP VIEW OF PORTION OF SIMPLE THROUGH TRUSS SPAN LOOKING UP AND NORTHEAST. - Huey P. Long Bridge, Spanning Mississippi River approximately midway between nine & twelve mile points upstream from & west of New Orleans, Jefferson, Jefferson Parish, LA
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7. DETAIL VIEW OF NORTHWEST WEB OF THE SOUTHEAST SPAN, SHOWING DECK, BRACING AND PANEL, LOOKING NORTHEAST - Linden Avenue Bridge, Spanning Purgatoire River on Linden Avenue, Trinidad, Las Animas County, CO
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20. OBLIQUE VIEW OF NORTH SIDE OF COOPER RIVER SPAN FROM EAST SHORE OF DRUM ISLAND, FACING SOUTHEAST - Grace Memorial Bridge, U.S. Highway 17 spanning Cooper River & Town Creek , Charleston, Charleston County, SC
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30. SOUTH SIDE OF COOPER RIVER CANTILEVER SPAN FROM WATER, FACING WEST TOWARDS DRUM ISLAND - Grace Memorial Bridge, U.S. Highway 17 spanning Cooper River & Town Creek , Charleston, Charleston County, SC
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48. OBLIQUE VIEW OF SOUTH SIDE OF COOPER RIVER SPAN, PEARMAN BRIDGE ON RIGHT, FACING EAST TOWARDS MOUNT PLEASANT FROM BRIDGE - Grace Memorial Bridge, U.S. Highway 17 spanning Cooper River & Town Creek , Charleston, Charleston County, SC
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24. OBLIQUE VIEW OF SOUTH SIDE OF COOPER RIVER SPAN FROM CHANNEL BELOW, PEARMAN BRIDGE ON RIGHT, FACING EAST - Grace Memorial Bridge, U.S. Highway 17 spanning Cooper River & Town Creek , Charleston, Charleston County, SC