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Polarization analysis of vector-meson production in pion-nucleon interactions
NASA Astrophysics Data System (ADS)
Arash, Firooz; Habibi, Mohammad F.
In view of the growing (though still incomplete) set of data on vector-meson production in pion-nucleon interactions, the polarization structure of this reaction is presented, together with polarization tests of one-particle-exchange processes in the s and t channels, as well as polarization tests for the Skyrmion model. The amplitude-observable relations are exhibited in the helicity, transversity, and planar-transverse frames. The desirable direction of future experimental programs is also outlined.
Backward pion-nucleon scattering
F. Huang; Sibirtsev, Alex; Haidenbauer, Johann; Meissner, Ulf-G.
A global analysis of the world data on differential cross sections and polarization asymmetries of backward pion-nucleon scattering for invariant collision energies above 3 GeV is performed in a Regge model. Including the $N_\\alpha$, $N_\\gamma$, $\\Delta_\\delta$ and $\\Delta_\\beta$ trajectories, we reproduce both angular distributions and polarization data for small values of the Mandelstam variable $u$, in contrast to previous analyses. The model amplitude is used to obtain evidence for baryon resonances with mass below 3 GeV. Our analysis suggests a $G_{39}$ resonance with a mass of 2.83 GeV as member of the $\\Delta_{\\beta}$ trajectory from the corresponding Chew-Frautschi plot.
Isospin breaking in low-energy pion-nucleon scattering
Gibbs, W.R.; Ai, L.; Kaufmann, W.B.
We have analyzed low-energy pion-nucleon data for isospin invariance by comparing charge-exchange amplitudes derived from charge-exchange data with those predicted from recent {pi}{sup {plus_minus}}{ital p} elastic data through the application of isospin invariance. A discrepancy of the order of 7% is observed beyond the contributions of the {pi}{sup {plus_minus}}{ital p} Coulomb interaction and the hadronic mass differences.
Low-energy pion-nucleon scattering
NASA Astrophysics Data System (ADS)
Gibbs, W. R.; Ai, Li; Kaufmann, W. B.
An analysis of low-energy charged pion-nucleon data from recent π+/-p experiments is presented. From the scattering lengths and the Goldberger-Miyazawa-Oehme (GMO) sum rule we find a value of the pion-nucleon coupling constant of f2=0.0756+/-0.0007. We also find, contrary to most previous analyses, that the scattering volumes for the P31 and P13 partial waves are equal, within errors, corresponding to a symmetry found in the Hamiltonian of many theories. For the potential models used, the amplitudes are extrapolated into the subthreshold region to estimate the value of the Σ term. Off-shell amplitudes are also provided.
Low-energy pion-nucleon scattering
Gibbs, W.R.; Ai, L.; Kaufmann, W.B.
An analysis of low-energy charged pion-nucleon data from recent {pi}{sup {plus_minus}}p experiments is presented. From the scattering lengths and the Goldberger-Miyazawa-Oehme (GMO) sum rule we find a value of the pion-nucleon coupling constant of f{sup 2}=0.0756{plus_minus}0.0007. We also find, contrary to most previous analyses, that the scattering volumes for the P{sub 31} and P{sub 13} partial waves are equal, within errors, corresponding to a symmetry found in the Hamiltonian of many theories. For the potential models used, the amplitudes are extrapolated into the subthreshold region to estimate the value of the {Sigma} term. Off-shell amplitudes are also provided. {copyright} {ital 1998} {ital The American Physical Society}
Remarks on the pion-nucleon σ-term
NASA Astrophysics Data System (ADS)
Hoferichter, Martin; Ruiz de Elvira, Jacobo; Kubis, Bastian; Meißner, Ulf-G.
The pion-nucleon σ-term can be stringently constrained by the combination of analyticity, unitarity, and crossing symmetry with phenomenological information on the pion-nucleon scattering lengths. Recently, lattice calculations at the physical point have been reported that find lower values by about 3σ with respect to the phenomenological determination. We point out that a lattice measurement of the pion-nucleon scattering lengths could help resolve the situation by testing the values extracted from spectroscopy measurements in pionic atoms.
a Phenomenological Determination of the Pion-Nucleon Scattering Lengths from Pionic Hydrogen
NASA Astrophysics Data System (ADS)
Ericson, T. E. O.; Loiseau, B.; Wycech, S.
A model independent expression for the electromagnetic corrections to a phenomenological hadronic pion-nucleon (πN) scattering length ah, extracted from pionic hydrogen, is obtained. In a non-relativistic approach and using an extended charge distribution, these corrections are derived up to terms of order α2 log α in the limit of a short-range hadronic interaction. We infer ahπ ^-p=0.0870(5)m-1π which gives for the πNN coupling through the GMO relation g2π ^± pn/(4π )=14.04(17).
Roy-Steiner-equation analysis of pion-nucleon scattering
NASA Astrophysics Data System (ADS)
Hoferichter, Martin; Ruiz de Elvira, Jacobo; Kubis, Bastian; Meißner, Ulf-G.
We review the structure of Roy-Steiner equations for pion-nucleon scattering, the solution for the partial waves of the t-channel process ππ → N ¯ N, as well as the high-accuracy extraction of the pion-nucleon S-wave scattering lengths from data on pionic hydrogen and deuterium. We then proceed to construct solutions for the lowest partial waves of the s-channel process πN → πN and demonstrate that accurate solutions can be found if the scattering lengths are imposed as constraints. Detailed error estimates of all input quantities in the solution procedure are performed and explicit parameterizations for the resulting low-energy phase shifts as well as results for subthreshold parameters and higher threshold parameters are presented. Furthermore, we discuss the extraction of the pion-nucleon σ-term via the Cheng-Dashen low-energy theorem, including the role of isospin-breaking corrections, to obtain a precision determination consistent with all constraints from analyticity, unitarity, crossing symmetry, and pionic-atom data. We perform the matching to chiral perturbation theory in the subthreshold region and detail the consequences for the chiral convergence of the threshold parameters and the nucleon mass.
Measurements of observables in the pion-nucleon system, nuclear a- dependence of heavy quark production and rare decays of D and B mesons
Sadler, M.E.; Isenhower, L.D.
This report discusses research on the following topics: pion-nucleon interactions; detector tomography facility; nuclear dependence of charm and beauty quark production and a study of two-prong decays of neutral D and B mesons; N* collaboration at CEBAF; and pilac experiments. (LSP)
Invited Parallel Talk: Forward pion-nucleon charge exchange reaction and Regge constraints
NASA Astrophysics Data System (ADS)
Huang, Fei; Sibirtsev, A.; Krewald, S.; Hanhart, C.; Haidenbauer, J.; Meißner, U.-G.
We present our recent study of pion-nucleon charge exchange amplitudes above 2 GeV. We analyze the forward pion-nucleon charge exchange reaction data in a Regge model and compare the resulting amplitudes with those from the Karlsruhe-Helsinki and George-Washington-University partial-wave analyses. We explore possible high-energy constraints for theoretical baryon resonance analyses in the energy region above 2 GeV. Our results show that for the pion-nucleon charge exchange reaction, the appropriate energy region for matching meson-nucleon dynamics to diffractive scattering should be around 3 GeV for the helicity flip amplitude.
A New Pion-Nucleon Partial Wave Analysis
NASA Astrophysics Data System (ADS)
Sadler, Michael; Watson, Shon; Stahov, Jugoslav
Existing determinations of the masses, widths and decay modes of low-lying excited states of the nucleon, as compiled in the Review of Particle Physics, are determined from energy-independent partial wave analyses of pion-nucleon scattering data. For the N*(1440) and most other resonances under 2 GeV, the analyses cited are the Karlsruhe-Helsinki, Carnegie Mellon-Berkeley and Kent State analyses, the latter of which used the elastic amplitudes from the other two. The data included in these analyses were published before 1980. Other analyses, notably the recent ones from George Washington University and the Pittsburgh-Argonne group, are ``not used for averages, fits, limits, etc.'' Complete sets of measurements (differential cross sections, analyzing powers and spin rotation parameters) have been measured in the N*(1440) resonance region since 1980, culminating in the Crystal Ball program at BNL to measure all-neutral final states (charge exchange, multiple pi-zero final states, and inverse photoproduction). A new partial wave analysis of the Karlsruhe-Helsinki type has been started by Abilene Christian University, University of Tuzla, and Rudjer Boskovic Institute. The analysis is constrained by fixed-t and interior hyperbolic dispersion relations. Comparisons of the new analysis to modern experimental data and to previous analyses will be presented.
Measurements of observables in the pion-nucleon system, nuclear a- dependence of heavy quark production and rare decays of D and B mesons. Progress report, 1 December, 1990--15 February, 1992
Sadler, M.E.; Isenhower, L.D.
This report discusses research on the following topics: pion-nucleon interactions; detector tomography facility; nuclear dependence of charm and beauty quark production and a study of two-prong decays of neutral D and B mesons; N* collaboration at CEBAF; and pilac experiments. (LSP)
Pion-nucleon charge exchange amplitudes above 2 GeV
NASA Astrophysics Data System (ADS)
Huang, F.; Sibirtsev, A.; Krewald, S.; Hanhart, C.; Haidenbauer, J.; Meißner, U.-G.
The amplitudes for the pion-nucleon charge exchange reaction of the Karlsruhe-Helsinki and the George-Washington-University partial-wave analyses are compared with those of a Regge-cut model with the aim to explore the possibility to provide high-energy constraints for theoretical baryon resonance analyses in the energy region above 2GeV.
Pion-nucleon scattering in covariant baryon chiral perturbation theory with explicit Delta resonances
NASA Astrophysics Data System (ADS)
Yao, De-Liang; Siemens, D.; Bernard, V.; Epelbaum, E.; Gasparyan, A. M.; Gegelia, J.; Krebs, H.; Meißner, Ulf-G.
We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explicit degrees of freedom. We work in a manifestly Lorentz invariant formulation of baryon chiral perturbation theory using dimensional regularization and the extended on-mass-shell renormalization scheme. In the delta resonance sector, the on mass-shell renormalization is realized as a complex-mass scheme. By fitting the low-energy constants of the effective Lagrangian to the S- and P -partial waves a satisfactory description of the phase shifts from the analysis of the Roy-Steiner equations is obtained. We predict the phase shifts for the D and F waves and compare them with the results of the analysis of the George Washington University group. The threshold parameters are calculated both in the delta-less and delta-full cases. Based on the determined low-energy constants, we discuss the pion-nucleon sigma term. Additionally, in order to determine the strangeness content of the nucleon, we calculate the octet baryon masses in the presence of decuplet resonances up to next-to-next-to-leading order in SU(3) baryon chiral perturbation theory. The octet baryon sigma terms are predicted as a byproduct of this calculation.
The pion nucleon scattering lengths from pionic hydrogen and deuterium
NASA Astrophysics Data System (ADS)
Schröder, H.-Ch.; Badertscher, A.; Goudsmit, P. F. A.; Janousch, M.; Leisi, H. J.; Matsinos, E.; Sigg, D.; Zhao, Z. G.; Chatellard, D.; Egger, J.-P.; Gabathuler, K.; Hauser, P.; Simons, L. M.; Rusi El Hassani, A. J.
This is the final publication of the ETH Zurich Neuchâtel PSI collaboration on the pionic hydrogen and deuterium precision X-ray experiments. We describe the recent hydrogen 3 p 1 s measurement, report on the determination of the Doppler effect correction to the transition line width, analyze the deuterium shift measurement and discuss implications of the combined hydrogen and deuterium results. From the pionic hydrogen 3 p 1 s transition experiments we obtain the strong-interaction energy level shift \\varepsilon_{1s} = -7.108±0.013 (stat.)±0.034 (syst.) eV and the total decay width Γ_{1s} = 0.868±0.040 (stat.)±0.038 (syst.) eV of the 1s state. Taking into account the electromagnetic corrections we find the hadronic π N s-wave scattering amplitude a_{π-prightarrowπ-p} = 0.0883±0.0008 m_{π}^{-1} for elastic scattering and a_{π-prightarrowπ0n} = -0.128±0.006 m_{π} ^{-1} for single charge exchange, respectively. We then combine the pionic hydrogen results with the 1 s level shift measurement on pionic deuterium and test isospin symmetry of the strong interaction: our data are still compatible with isospin symmetry. The isoscalar and isovector π N scattering lengths (within the framework of isospin symmetry) are found to be b_0 = -0.0001^{+0.0009}_{-0.0021} m_{π}^{-1} and b1 = -0.0885^{+0.0010}_{-0.0021} m_{π} ^{-1}, respectively. Using the GMO sum rule, we obtain from b_1 a new value of the π N coupling constant (g_{π N} = 13.21_{-0.05}^{+0.11}) from which follows the Goldberger Treiman discrepancy Δ_{{GT}} =0.027_{-0.008}^{+0.012}. The new values of b_0 and g_{π N} imply an increase of the nucleon sigma term by at least 9 MeV.
Elastic pion-nucleon scattering in chiral perturbation theory: A fresh look
NASA Astrophysics Data System (ADS)
Siemens, D.; Bernard, V.; Epelbaum, E.; Gasparyan, A.; Krebs, H.; Meißner, Ulf-G.
Elastic pion-nucleon scattering is analyzed in the framework of chiral perturbation theory up to fourth order within the heavy-baryon expansion and a covariant approach based on an extended on-mass-shell renormalization scheme. We discuss in detail the renormalization of the various low-energy constants and provide explicit expressions for the relevant β functions and the finite subtractions of the power-counting breaking terms within the covariant formulation. To estimate the theoretical uncertainty from the truncation of the chiral expansion, we employ an approach which has been successfully applied in the most recent analysis of the nuclear forces. This allows us to reliably extract the relevant low-energy constants from the available scattering data at low energy. The obtained results provide clear evidence that the breakdown scale of the chiral expansion for this reaction is related to the Δ resonance. The explicit inclusion of the leading contributions of the Δ isobar is demonstrated to substantially increase the range of applicability of the effective field theory. The resulting predictions for the phase shifts are in an excellent agreement with the predictions from the recent Roy-Steiner-equation analysis of pion-nucleon scattering.
A relativistic meson-exchange model of pion-nucleon scattering
Lee, T.S.H.; Hung, C.T.; Yang, S.N.
Pion-nucleon scattering is investigated using the Kadshevsky three-dimensional reduction of the Bethe-Salpeter equation. The resulting potential includes the direct and crossed N and {Delta} terms, and the t-channel {sigma}- and {rho}-exchange terms. The nucleon-pole condition is imposed to define the renormalization of the nucleon mass and the {pi}NN coupling constant. A mixture of the scalar and vector {sigma}{pi}{pi} couplings is introduced to simulate the broad width of the s-wave correlated two-pion exchange mechanism. Good descriptions of the {pi}N phase shifts up to 400 MeV have been obtained in all S- and P-waves. The off-shell behavior for our model differs significantly from that obtained using different reductions. A paper describing our results was published.
Pion-nucleon scattering in the Skyrme model and the P-wave Born amplitudes
NASA Astrophysics Data System (ADS)
Hayashi, A.; Saito, S.; Uehara, M.
We treat fluctuating pion fields around a rotating Skyrmion by means of Dirac's quantization method. The rotational collective motion of the Skyrmion is described by collective coordinates, and conventional gauge-fixing conditions are imposed. Taking into account all the relevant terms at the tree level appearing in the Hamiltonian, we show that pion-nucleon scattering amplitudes exhibit the P-wave Born amplitudes attributed to the Yukawa coupling of order √Nc , which is consistent with the prediction of chiral symmetry such as the Adler-Weisberger relation. This resolves the difficulty that the Skyrme model predicts a wrong Nc dependence for the coupling of order N-3/2c.
Chiral representation of the πN scattering amplitude and the pion-nucleon sigma term
NASA Astrophysics Data System (ADS)
Alarcón, J. M.; Camalich, J. Martin; Oller, J. A.
We present a novel analysis of the πN scattering amplitude in Lorentz covariant baryon chiral perturbation theory renormalized in the extended-on-mass-shell scheme. This amplitude, valid up to O(p3) in the chiral expansion, systematically includes the effects of the Δ(1232) in the δ-counting, has the right analytic properties, and is renormalization-scale independent. This approach overcomes the limitations that previous chiral analyses of the πN scattering amplitude had, providing an accurate description of the partial wave phase shifts of the Karlsruhe-Helsinki and George-Washington groups up to energies just below the resonance region. We also study the solution of the Matsinos group which focuses on the parameterization of the data at low energies. Once the values of the low-energy constants are determined by adjusting the center-of-mass energy dependence of the amplitude to the scattering data, we obtain predictions on different observables. In particular, we extract an accurate value for the pion-nucleon sigma term, σπN. This allows us to avoid the usual method of extrapolation to the unphysical region of the amplitude. Our study indicates that the inclusion of modern meson-factory and pionic-atom data favors relatively large values of the sigma term. We report the value σπN=59(7)MeV and comment on implications that this result may have.
Pion-Nucleon Scattering and Analysis from threshold to the N*(1440) Resonance Region
NASA Astrophysics Data System (ADS)
Sadler, Michael; Watson, Shon; Stahov, Jugoslav
Many measurements for pion-nucleon scattering from threshold to the N*(1440) resonance region have been made since 1980, when the landmark Karlsruhe-Helsinki (KH) and Carnegie Mellon-Berkeley (CMB) partial wave analyses (PWA) were completed. These measurements consist of differential cross sections and analyzing powers for elastic scattering and charge exchange. Spin rotation parameters for elastic scattering in the momentum interval 0.4 -- 0.7 GeV/c have also been obtained. The program culminated with measurements of π-p -> Neutrals (charge exchange, multiple pi-zero final states, eta production, and inverse photoproduction) using the Crystal Ball at BNL. Resonance parameters for the N*(1440) in the Review of Particle Physics by the Particle Data Group have been obtained from the KH and CMB analyses. The 2006 edition also includes the analysis by George Washington University (GWU) ``for averages, fits, limits, etc.'', but the parameters were unchanged. An overview of the data will be presented along with comparisons to PWA.
Determination of the pion-nucleon coupling constant and scattering lengths
NASA Astrophysics Data System (ADS)
Ericson, T. E.; Loiseau, B.; Thomas, A. W.
We critically evaluate the isovector Goldberger-Miyazawa-Oehme (GMO) sum rule for forward πN scattering using the recent precision measurements of π-p and π-d scattering lengths from pionic atoms. We deduce the charged-pion-nucleon coupling constant, with careful attention to systematic and statistical uncertainties. This determination gives, directly from data, g2c(GMO)/ 4π=14.11+/-0.05(statistical)+/-0.19(systematic) or f2c/4π=0.0783(11). This value is intermediate between that of indirect methods and the direct determination from backward np differential scattering cross sections. We also use the pionic atom data to deduce the coherent symmetric and antisymmetric sums of the pion-proton and pion-neutron scattering lengths with high precision, namely, (aπ-p+aπ-n)/2=[- 12+/-2(statistical)+/-8(systematic)]×10-4 m-1π and (aπ-p-aπ- n)/2=[895+/-3(statistical)+/-13 (systematic)]×10-4 m-1π. For the need of the present analysis, we improve the theoretical description of the pion-deuteron scattering length.
Axial, induced pseudoscalar, and pion-nucleon form factors in manifestly Lorentz-invariant chiral perturbation theory
Schindler, M. R.; Fuchs, T.; Scherer, S.; Gegelia, J.
We calculate the nucleon form factors G{sub A} and G{sub P} of the isovector axial-vector current and the pion-nucleon form factor G{sub {pi}}{sub N} in manifestly Lorentz-invariant baryon chiral perturbation theory up to and including order O(p{sup 4}). In addition to the standard treatment including the nucleon and pions, we also consider the axial-vector meson a{sub 1} as an explicit degree of freedom. This is achieved by using the reformulated infrared renormalization scheme. We find that the inclusion of the axial-vector meson effectively results in one additional low-energy coupling constant that we determine by a fit to the data for G{sub A}. The inclusion of the axial-vector meson results in an improved description of the experimental data for G{sub A}, while the contribution to G{sub P} is small.
New Aspects of Experimental Study of the Pion-Nucleon Interaction in the Resonance Region
Sumachev, V.V.
New experimental data that were obtained by the PNPI-ITEP Collaboration have resolved some discrete ambiguities in the partial-wave analysis (PWA). These results were used in the new FA02 PWA performed at George Washington University. At the same time, the FA02 PWA has revealed considerable fewer N* and {delta} resonances than those listed in the RPP tables. This circumstance aggravated the known problem of so-called missing resonances. The program for further measurements of the spin rotation parameters in elastic {pi}N scattering that are required to eliminate the remaining discrete PWA ambiguities is discussed.
Pion-nucleon correlations in finite nuclei in a relativistic framework: Effects on the shell structure
NASA Astrophysics Data System (ADS)
Litvinova, Elena
The relativistic particle-vibration coupling (RPVC) model is extended by the inclusion of isospin-flip excitation modes into the phonon space, introducing a new mechanism of dynamical interaction between nucleons with different isospin in the nuclear medium. Protons and neutrons exchange by collective modes which are formed by isovector π and ρ-mesons, in turn, softened considerably because of coupling to nucleons of the medium. These modes are investigated within the proton-neutron relativistic random phase approximation (pn-RRPA) and relativistic proton-neutron time blocking approximation (pn-RTBA). The appearance of isospin-flip states with sizable transition probabilities at low energies points out that they are likely to couple to the single-particle degrees of freedom and, in addition to isoscalar low-lying phonons, to modify their spectroscopic characteristics. Such a coupling is quantified for the shell structure of 100,132Sn and found significant for the location of the dominant single-particle states.
Baryon fields with UL(3 ) ×UR(3 ) chiral symmetry. V. Pion-nucleon and kaon-nucleon Σ terms
NASA Astrophysics Data System (ADS)
Dmitrašinović, V.; Chen, Hua-Xing; Hosaka, Atsushi
We have previously calculated the pion-nucleon Σπ N term in the chiral mixing approach with u ,d flavors only, and found the lower bound Σπ N≥(" close=")mu0+md0)">1 +16/3 sin2θ 3/2 (gA(0 )+gA(3 )) , where gA(0 ),gA(3 ) , are the flavor-singlet and the isovector axial couplings. With presently accepted values of current quark masses, this leads to Σπ N≥58.0 ±4.5 -6.5+11.4 MeV, which is in agreement with the values extracted from experiments, and substantially higher than most previous two-flavor calculations. The causes of this enhancement are: (1) the large, (16/3 ≃5.3 ), purely SUL(2 ) ×SUR(2 ) algebraic factor; (2) the admixture of the [(1 ,1/2 ) ⊕(1/2 ,1 ) ] chiral multiplet component in the nucleon, whose presence has been known for some time, but that had not been properly taken into account, yet. We have now extended these calculations of Σπ N to three light flavors, i.e., to SUL(3 ) ×SUR(3 ) multiplet mixing. Phenomenology of chiral SUL(3 ) ×SUR(3 ) multiplet mixing demands the presence of three chiral SUL(3 ) ×SUR(3 ) multiplets, viz. [(6 ,3 )⊕(3 ,6 )],[(3 ,3 ¯) ⊕(3 ¯,3 ) ] , and [(3 ¯,3 ) ⊕(3 ,3 ¯) ] , in order to successfully reproduce the baryons' flavor-octet and flavor-singlet axial current coupling constants, as well as the baryon anomalous magnetic moments. Here we use these previously obtained results, together with known constraints on the explicit chiral symmetry breaking in baryons to calculate the Σπ N term, but find no change of Σπ N from the above successful two-flavor result. The physical significance of these results lies in the fact that they show no need for q4q ¯ components, and in particular, no need for an s s ¯ component in the nucleon, in order to explain the large "observed" Σπ N value. We also predict the kaon-nucleon σ term ΣK N that is experimentally unknown, but may be calculable in lattice QCD.
Toward complete pion nucleon amplitudes
NASA Astrophysics Data System (ADS)
Mathieu, V.; Danilkin, I. V.; Fernández-Ramírez, C.; Pennington, M. R.; Schott, D.; Szczepaniak, Adam P.; Fox, G.
We compare the low-energy partial-wave analyses of π N scattering with high-energy data via finite-energy sum rules. We construct a new set of amplitudes by matching the imaginary part from the low-energy analysis with the high-energy, Regge parametrization and reconstruct the real parts using dispersion relations.
Toward complete pion nucleon amplitudes
Mathieu, Vincent; Danilkin, Igor V.; Fernández-Ramírez, Cesar; Pennington, Michael R.; Schott, Diane M.; Szczepaniak, Adam P.; Fox, G.
We compare the low-energy partial wave analyses πN scattering with a high-energy data via finite energy sum rules. We also construct a new set of amplitudes by matching the imaginary part from the low-energy analysis with the high-energy, Regge parametrization and then reconstruct the real parts using dispersion relations.
Determination of partial-wave inelasticities for elastic pion-nucleon scattering with the aid of experimental data on π N → ππ N processes in the beam-momentum range 300 < P beam < 500 MeV/ c
NASA Astrophysics Data System (ADS)
Kozhevnikov, V. A.; Sherman, S. G.
The partial-wave inelasticity parameters of the amplitude for elastic pion-nucleon scattering are determined with the aid of the phenomenological amplitude for inelastic π N → ππ N processes in the energy range extending to the threshold for the production of two pions. The resulting inelasticity parameters are compared with their counterparts derived from modern partial-wave analyses. The largest inelastic-scattering cross section in the P11 wave is in excellent agreement with the analogous value from the analysis performed at the George Washington University in 2006. For other waves, however, the present results differ in the majority of cases from respective values given by partial-wave analyses (the distinctions are especially large for the isospin-3/2 amplitudes).
Experimental studies of pion-nucleus interactions at intermediate energies
Not Available
This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991 under a great from the US Department of Energy. Most of these studies have involved investigations of various pion-nucleus interactions. The work has been carried out both with the LAMPF accelerator at the Los Alamos National Laboratory and with the cyclotron at the Paul Scherrer Institute (PSI) near Zurich, Switzerland. Part of the experimental work involves measurements of new data on double-charge-exchange scattering, using facilities at LAMPF which we helped modify, and on pion absorption, using a new detector system at PSI that covers nearly the full solid-angle region which we helped construct. Other work involved preparation for future experiments using polarized nuclear targets and a new high-resolution spectrometer system for detecting {pi}{sup 0} mesons. We also presented several proposals for works to be done in future years, involving studies related to pi-mesonic atoms, fundamental pion-nucleon interactions, studies of the difference between charged and neutral pion interactions with the nucleon, studies of the isospin structure of pion-nucleus interactions, and pion scattering from polarized {sup 3}He targets. This work is aimed at improving our understanding of the pion-nucleon interaction, of the pion-nucleus interaction mechanism, and of nuclear structure.
Experimental studies of pion-nucleus interactions at intermediate energies. Annual progress report
Not Available
This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991 under a great from the US Department of Energy. Most of these studies have involved investigations of various pion-nucleus interactions. The work has been carried out both with the LAMPF accelerator at the Los Alamos National Laboratory and with the cyclotron at the Paul Scherrer Institute (PSI) near Zurich, Switzerland. Part of the experimental work involves measurements of new data on double-charge-exchange scattering, using facilities at LAMPF which we helped modify, and on pion absorption, using a new detector system at PSI that covers nearly the full solid-angle region which we helped construct. Other work involved preparation for future experiments using polarized nuclear targets and a new high-resolution spectrometer system for detecting {pi}{sup 0} mesons. We also presented several proposals for works to be done in future years, involving studies related to pi-mesonic atoms, fundamental pion-nucleon interactions, studies of the difference between charged and neutral pion interactions with the nucleon, studies of the isospin structure of pion-nucleus interactions, and pion scattering from polarized {sup 3}He targets. This work is aimed at improving our understanding of the pion-nucleon interaction, of the pion-nucleus interaction mechanism, and of nuclear structure.
Hadronic event generation for hadron cascade calculations and detector simulation, Part IV: The application of the intranuclear cascade model to reactions of pions, nucleons, kaons, and their antiparticles with nuclei below 6 GeV/c
Haenbssgen, K.
An extension of the intranuclear cascade model is described. The primary hadrons may be pions, kaons, nucleons, and their antiparticles. Secondary particles produced include hyperons or antihyperons. A large amount of experimental data is described by the model. The model is constructed via the Monte Carlo generation of complete events, based on a model of the nucleus structure and the hadron/nucleon interaction inside the nucleus. Calculated average multiplicities and single and double differential cross sections are compared with experimental data.
Delta: the First Pion Nucleon Resonance - Its Discovery and Applications
DOE R&D Accomplishments Database
Nagle, D. E.
It is attempted to recapture some of the fun and excitement of the pion-scattering work that led to the discovery of what is now called the delta particle. How significant this discovery was became apparent only gradually. That the delta is alive today and thriving at Los Alamos (as well as other places) is described.
Delta: the first pion nucleon resonance - its discovery and applications
Nagle, D.E.
It is attempted to recapture some of the fun and excitement of the pion-scattering work that led to the discovery of what is now called the delta particle. How significant this discovery was became apparent only gradually. That the delta is alive today and thriving at Los Alamos (as well as other places) is described.
First results for electromagnetic three-nucleon form factors from high-precision two-nucleon interactions
Sergio Alexandre Pinto; Stadler, Alfred; Gross, Franz L.
The electromagnetic form factors of the three-nucleon bound states were calculated in Complete Impulse Approximation in the framework of the Covariant Spectator Theory for the new high-precision two-nucleon interaction models WJC-1 and WJC-2. The calculations use an approximation for the three-nucleon vertex functions with two nucleons off mass shell. The form factors with WJC-2 are close to the ones obtained with the older model W16 and to nonrelativistic potential calculations with lowest-order relativistic corrections, while the form factors with the most precise two-nucleon model WJC-1 exhibit larger differences. These results can be understood when the effect of the different types of pion-nucleon coupling used in the various models is examined.
Hadronic Weak Interaction Studies at the SNS
NASA Astrophysics Data System (ADS)
Fomin, Nadia
Neutrons have been a useful probe in many fields of science, as well as an important physical system for study in themselves. Modern neutron sources provide extraordinary opportunities to study a wide variety of physics topics. Among them is a detailed study of the weak interaction. An overview of studies of the hadronic weak (quark-quark) as well as semi-leptonic (quark-lepton) interactions at the Spallation Neutron Source (SNS) is presented. These measurements, done in few-nucleon systems, are finally letting us gain knowledge of the hadronic weak interaction without the contributions from nuclear effects. Forthcoming results from the NPDGamma experiment will, due to the simplicity of the neutron, provide an unambiguous measurement of the long range pion-nucleon weak coupling (often referred to as hπ), which will finally test the theoretical predictions. Results from NPDGamma and future results from the n +3 He experiment will need to be complemented by additional measurements to completely describe the hadronic weak interaction.
Transition from hadronic to partonic interactions for a composite spin-1/2 model of a nucleon
Tjon, J. A.; Wallace, S. J.
A simple model of a composite nucleon is developed in which a fermion and a boson, representing quark and diquark constituents of the nucleon, form a bound state owing to a contact interaction. Photon and pion couplings to the quark provide vertex functions for the photon and pion interactions with the composite nucleon. By a suitable choice of cutoff parameters of the model, realistic electromagnetic form factors are obtained for the proton. When a pseudoscalar pion-quark coupling is used, the pion-nucleon coupling is predominantly pseudovector. A virtual photopion amplitude is considered in which there are two types of contributions: hadronic contributions where the photon and pion interactions have an intervening propagator of the nucleon or its excited states, and contactlike contributions where the photon and pion interactions occur within a single vertex. At large Q, the contactlike contributions are dominant. The model nucleon exhibits scaling behavior in deep-inelastic scattering and the normalization of the parton distribution provides a rough normalization of the contactlike contributions. Calculations for the virtual photopion amplitude are performed using kinematics appropriate to its occurrence as a meson-exchange current in electron-deuteron scattering. The results suggest that the contactlike terms can dominate the meson-exchange current for Q>1GeV/c. There is a direct connection of the contactlike terms to the off-forward parton distributions of the model nucleon.
Experimental studies of the quark-gluon structure of nucleons and nuclei and of pion- and proton-nucleus interactions. Progress report, April 1, 1994--March 31, 1997
This report summarizes the work on experimental research in intermediate energy nuclear physics carried out by New Mexico State University from April 1, 1994, through March 31, 1996 under a grant from the US Department of Energy. During this period we began phasing out our programs of study of pion-nucleus and pion-nucleon interaction and of nucleon-nucleus charge-exchange reactions, which have been our major focus of the past two or three years. At the same time we continued moving in a new direction of research on studies of the internal structure of nucleons and nuclei in terms of quarks and gluons. The pion and nucleon work has been aimed at improving our understanding of the nature of pion and proton interactions in the nuclear medium and of various aspects of nuclear structure. The studies of the quark-gluon structure of nucleons are aimed at clarifying such problems as the nature of the quark sea and the relation of the nucleon spin to the spins of the quarks within the nucleon, questions which are of a very fundamental nature.
Uncertainty Analysis and Order-by-Order Optimization of Chiral Nuclear Interactions
NASA Astrophysics Data System (ADS)
Carlsson, B. D.; Ekström, A.; Forssén, C.; Strömberg, D. Fahlin; Jansen, G. R.; Lilja, O.; Lindby, M.; Mattsson, B. A.; Wendt, K. A.
Chiral effective field theory (χ EFT ) provides a systematic approach to describe low-energy nuclear forces. Moreover, χ EFT is able to provide well-founded estimates of statistical and systematic uncertainties—although this unique advantage has not yet been fully exploited. We fill this gap by performing an optimization and statistical analysis of all the low-energy constants (LECs) up to next-to-next-to-leading order. Our optimization protocol corresponds to a simultaneous fit to scattering and bound-state observables in the pion-nucleon, nucleon-nucleon, and few-nucleon sectors, thereby utilizing the full model capabilities of χ EFT . Finally, we study the effect on other observables by demonstrating forward-error-propagation methods that can easily be adopted by future works. We employ mathematical optimization and implement automatic differentiation to attain efficient and machine-precise first- and second-order derivatives of the objective function with respect to the LECs. This is also vital for the regression analysis. We use power-counting arguments to estimate the systematic uncertainty that is inherent to χ EFT , and we construct chiral interactions at different orders with quantified uncertainties. Statistical error propagation is compared with Monte Carlo sampling, showing that statistical errors are, in general, small compared to systematic ones. In conclusion, we find that a simultaneous fit to different sets of data is critical to (i) identify the optimal set of LECs, (ii) capture all relevant correlations, (iii) reduce the statistical uncertainty, and (iv) attain order-by-order convergence in χ EFT . Furthermore, certain systematic uncertainties in the few-nucleon sector are shown to get substantially magnified in the many-body sector, in particular when varying the cutoff in the chiral potentials. The methodology and results presented in this paper open a new frontier for uncertainty quantification in ab initio nuclear theory.
The effective chiral Lagrangian from the theta term
Mereghetti, E.; Hockings, W.H.; Kolck, U. van
We construct the effective chiral Lagrangian involving hadronic and electromagnetic interactions originating from the QCD {theta}-bar term. We impose vacuum alignment at both quark and hadronic levels, including field redefinitions to eliminate pion tadpoles. We show that leading time-reversal-violating (TV) hadronic interactions are related to isospin-violating interactions that can in principle be determined from charge-symmetry-breaking experiments. We discuss the complications that arise from TV electromagnetic interactions. Some implications of the expected sizes of various pion-nucleon TV interactions are presented, and the pion-nucleon form factor is used as an example.
Recent results of the parameters A and R measurements in the resonance region of the πN-elastic scattering and subsequent investigations.
NASA Astrophysics Data System (ADS)
Sumachev, V. V.; Beloglazov, Yu. A.; Filimonov, E. A.; Kovalev, A. I.; Kozlenko, N. G.; Kruglov, S. P.; Kulbardis, A. A.; Lopatin, I. V.; Novinsky, D. V.; Shchedrov, V. A.; Trautman, V. Yu.; Alekseev, I. G.; Budkovsky, P. E.; Kanavets, V. P.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Ryltsov, V. V.; Sulimov, A. D.; Svirida, D. N.; Bazhanov, N. A.; Bunyatova, E. I.
The existing models of baryons usually predict considerably more resonance (three or more in number) than it was found by investigation of elastic pion-nucleon scattering. This disagreement invites further investigation of the pion-nucleon interaction and among other things the measurement of spin rotation parameters A and R in the elastic pion-nucleon scattering. Recent experiments of the PNPI and PNPI-ITEP collaborations resolved a part of twofold ambiguities of the existing partial wave analyses (PWA). These results were used in the last PWA of the George Washington University group SP06. The proposal for the additional spin rotation parameters A and R measurement in the resonance region is motivated. Such additional measurements are necessary to resolve remaining twofold ambiguities of the existing PWAs.
Recent results of the parameters A and R measurements in the resonance region of the {pi}N-elastic scattering and subsequent investigations
Sumachev, V. V.; Beloglazov, Yu. A.; Filimonov, E. A.; Kovalev, A. I.; Kozlenko, N. G.; Kruglov, S. P.; Kulbardis, A. A.; Lopatin, I. V.; Novinsky, D. V.; Shchedrov, V. A.; Trautman, V. Yu.; Alekseev, I. G.; Budkovsky, P. E.; Kanavets, V. P.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Ryltsov, V. V.; Sulimov, A. D.; Svirida, D. N.
The existing models of baryons usually predict considerably more resonance (three or more in number) than it was found by investigation of elastic pion-nucleon scattering. This disagreement invites further investigation of the pion-nucleon interaction and among other things the measurement of spin rotation parameters A and R in the elastic pion-nucleon scattering.Recent experiments of the PNPI and PNPI-ITEP collaborations resolved a part of twofold ambiguities of the existing partial wave analyses (PWA). These results were used in the last PWA of the George Washington University group SP06. The proposal for the additional spin rotation parameters A and R measurement in the resonance region is motivated. Such additional measurements are necessary to resolve remaining twofold ambiguities of the existing PWAs.
Including the {delta}(1232) resonance in baryon chiral perturbation theory
Hacker, C.; Wies, N.; Scherer, S.; Gegelia, J.
Baryon chiral perturbation theory with explicit {delta}(1232) degrees of freedom is considered. The most general interactions of pions, nucleons, and {delta} consistent with all underlying symmetries as well as with the constraint structure of higher-spin fields are constructed. By use of the extended on-mass-shell renormalization scheme, a manifestly Lorentz-invariant effective-field theory with a systematic power counting is obtained. As applications, we discuss the mass of the nucleon, the pion-nucleon {sigma} term, and the pole of the {delta} propagator.
Direct electromagnetic excitation N. --> delta. (1232), final-state interactions, and the multipoles M/sub 1//sub +//sup() 3/2/ and E/sub 1//sub +//sup() 3/2/ of photopion production off nucleons in the range 160< or approx. =E/sub. gamma. /< or approx. =800 MeV
Jurewicz, A.
In this paper one of the classics of particle theory in the resonance region is reexamined, namely the prediction of the amplitudes M/sub 1//sub +//sup() 3/2/ and E/sub 1//sub +//sup() 3/2/ of photopion production on nucleons around the resonance ..delta..(1232). The tool employed for this purpose is the final-state-interaction theory, and the principal aim of the study is to advocate for the appearance of two distinct dynamical mechanisms of photoexcitation in such an approach. Special emphasis is put then on the naturally emerging links between the present treatment and the isobaric approach and calculations based on the static quark model. It is argued that the dynamical meaning of the troublesome arbitrary constants (known to appear in most studies of the type presented in this paper) can be very convincingly explained when the resonances formed in the reaction (..delta..(1232) in this specific case) are treated as ''elementary'' objects represented in the T-matrix elements by singularities of the Castillejo-Dalitz-Dyson kind. In the case discussed here, ''direct'' magnetic-dipole excitation N..--> delta..(1232) seems to emerge very clearly as an independent dynamical mechanism of photoproduction in the p/sub 33/ state, parallel to the usual electromagnetic excitation of nonresonant ..pi..N systems, both followed by resonant pion-nucleon rescattering. It turns out that the magnitude of such direct ..gamma..N..delta.. coupling is completely determined by the related strong interactions. The necessity of allowing for both specified mechanisms in this and other similar calculations is emphasized.
The two-nucleon system at next-to-next-to-next-to-leading order
Evgeny Epelbaum; Walter Gloeckle; Ulf-G. Meissner
We consider the two-nucleon system at next-to-next-to-next-to-leading order (N{sup 3}LO) in chiral effective field theory. The two--nucleon potential at N{sup 3}LO consists of one-, two- and three-pion exchanges and a set of contact interactions with zero, two and four derivatives. In addition, one has to take into account various isospin--breaking and relativistic corrections. We employ spectral function regularization for the multi--pion exchanges. Within this framework, it is shown that the three-pion exchange contribution is negligibly small. The low--energy constants (LECs) related to pion-nucleon vertices are taken consistently from studies of pion-nucleon scattering in chiral perturbation theory. The total of 26 four--nucleon LECs has been determined by a combined fit to some np and pp phase shifts from the Nijmegen analysis together with the nn scattering length.
Soft two-pion-exchange nucleon-nucleon potentials
Rijken, Th.A. )
Two-pion-exchange nucleon-nucleon potentials are derived for the pseudo-vector pion-nucleon interaction, assuming strong dynamical pair-suppression. At the pion-nucleon vertices the authors include Gaussian form factors, which are incorporated into the relativistic two-body framework by using a dispersion representation for the one-pion-exchange amplitude. The Fourier transformations are performed using a factorization technique for the energy denominators. This leads to analytic expressions for the TPE-potentials containing at most one-dimensional integrals. The TPE-potentials are calculated up to orders {line integral}{sup 4} and (m/M){line integral}{sup 4}. The terms of order {line integral}{sup 4} come from the adiabatic contributions of the parallel and crossed three-dimensional momentum-space TPE-diagrams, and from the non-adiabatic contributions of the OPE-iteration. The (m/M)-corrections are due to the 1/M-terms in the non-adiabatic expansion of the nucleon energies in the intermediate states, and the 1/M-terms in the pion-nucleon vertices. The latter are typical for the PV-coupling and would be absent for the PS-coupling. The Gaussian form factors lead to soft TPE-potentials. These potentials can readily be exploited in NN-calculations in combination with, e.g., the Nijmegen soft-core OBE-model, and in nuclear (matter) calculations.
The width of the Roper resonance in baryon chiral perturbation theory
NASA Astrophysics Data System (ADS)
Gegelia, Jambul; Meißner, Ulf-G.; Yao, De-Liang
We calculate the width of the Roper resonance at next-to-leading order in a systematic expansion of baryon chiral perturbation theory with pions, nucleons, and the delta and Roper resonances as dynamical degrees of freedom. Three unknown low-energy constants contribute up to the given order. One of them can be fixed by reproducing the empirical value for the width of the Roper decay into a pion and a nucleon. Assuming that the remaining two couplings of the Roper interaction take values equal to those of the nucleon, the result for the width of the Roper decaying into a nucleon and two pions is consistent with the experimental value.
A dynamical model for pion electroproduction on the nucleon
George L. Caia; Louis E. Wright; Vladimir Pascalutsa
We develop a Lorenz- and gauge-invariant dynamical model for pion electroproduction in the resonance region. The model is based on solving of the Salpeter (instantaneous) equation for the pion-nucleon interaction with a hadron-exchange potential. We find that the one-particle-exchange kernel of the Salpeter equation for pion electroproduction develops an unphysical singularity for a finite value of Q{sup 2}. We analyze two methods of dealing with this problem. Results of our model are compared with recent single-polarization data for pion electroproduction.
Program of Measurement of the Asymmetry P at the Minima of the Differential Cross Section for Elastic {pi}{sup +}p Scattering
Beloglazov, Yu.A.; Kovalev, A.I.; Kruglov, S.P.; Novinsky, D.V.; Sumachev, V.V.; Trautman, V.Yu.; Filimonov, E.A.; Shchedrov, V.A.; Alekseev, I.G.; Budkovsky, P.E.; Zhurkin, V.V.; Kanavets, V.P.; Koroleva, L.I.; Morozov, B.V.; Nesterov, V.M.; Ryltsov, V.V.; Svirida, D.N.; Sulimov, A.D.; Bazhanov, N.A.; Bunyatova, E.I.
A program of measurement of the polarization parameter P in elastic {pi}{sup +}p interaction in the resonance region of backward pion scattering is presented. This program is aimed at determining the bifurcation points of the trajectory of zeros of the pion-nucleon amplitude and, hence, at unambiguously reconstructing the amplitude of {pi}N scattering in the second resonance region. It is planned to perform a relevant experiment in a pion beam from the accelerator of the Institute of Experimental and Theoretical Physics (ITEP, Moscow)
Phenomenological Implications of the Nucleon's Meson Cloud
NASA Astrophysics Data System (ADS)
Hobbs, T. J.
The long-distance structure of the interacting nucleon receives important contributions from its couplings to light hadronic degrees of freedom—a light meson cloud—while an analogous nonperturbative mechanism is expected to generate an intrinsic charm (IC) component to the proton wavefunction. We investigate both possibilities, keeping for the former a special eye to improving the theoretical understanding of the pion-nucleon vertex in light of proposed measurements. Regarding the latter possibility of IC, we highlight recent results obtained by a global QCD analysis of the light-front model proposed in Hobbs et al. (Phys Rev D 89:074008, 2014).
ERIC Educational Resources Information Center
Dombro, Amy Laura; Jablon, Judy R.; Stetson, Charlotte
Interactions are the daily exchanges in words and gestures one has with others. As a teacher, the interactions he/she has with young children can make a positive difference in their lives. A teacher's powerful interactions with children play an important role in their emotional well-being and learning. Powerful interactions are not the same as…
Tong Logan, Angela; Silverman, Andrew
One of the most clinically significant complications related to the use of pharmacotherapy is the potential for drug-drug or drug-disease interactions. The gastrointestinal system plays a large role in the pharmacokinetic profile of most medications, and many medications utilized in gastroenterology have clinically significant drug interactions. This review will discuss the impact of alterations of intestinal pH, interactions mediated by phase I hepatic metabolism enzymes and P-glycoprotein, the impact of liver disease on drug metabolism, and interactions seen with commonly utilized gastrointestinal medications. PMID:22933873
ERIC Educational Resources Information Center
Honeycutt, James M.
Social scientists have been studying imagined interactions since the mid-1980s and have measured numerous physiological correlates (Honeycutt, 2010). In this commentary I assess the research reported in Crisp and Turner (May-June 2009) and highlight the underlying mechanisms of imagined interactions that have empirically been laid out across…
Absorption of {Lambda}(1520) hyperons in photon-nucleus collisions
Paryev, E. Ya.
In the framework of the nuclear spectral function approach for incoherent primary photon-nucleon and secondary pion-nucleon production processes we study the inclusive {Lambda}(1520)-hyperon production in the interaction of 2-GeV photons with nuclei. In particular, the A and momentum dependences of the absolute and relative {Lambda}(1520)-hyperon yields are investigated in two scenarios for its in-medium width. Our model calculations show that the pion-nucleon production channel contributes appreciably to the {Lambda}(1520) creation at intermediate momenta both in light and heavy nuclei in the chosen kinematics and, hence, has to be taken into consideration on close examination of the dependences of the {Lambda}(1520)-hyperon yields on the target mass number with the aim to get information on its width in the medium. They also demonstrate that the A and momentum dependences of the absolute and relative {Lambda}(1520)-hyperon production cross sections at incident energy of interest are markedly sensitive to the {Lambda}(1520) in-medium width, which means that these observables may be an important tool to determine the above width.
Attenuation of {Lambda}(1520) Hyperons in near-threshold pA reactions
Paryev, E. Ya.
In the framework of the nuclear spectral function approach for incoherent primary proton-nucleon and secondary pion-nucleon production processes we study the inclusive {Lambda}(1520)-hyperon production in the interaction of 2.83-GeV protons with nuclei. In particular, the A and momentum dependences of the absolute and relative {Lambda}(1520)-hyperon yields are investigated within the different scenarios for their in-medium width. Our model calculations show that the pion-nucleon production channel contributes distinctly to the 'low-momentum' {Lambda}(1520) creation both in light and heavy nuclei in the chosen kinematics and, hence, has to be taken into consideration on close examination of the dependences of the {Lambda}(1520)-hyperon yields on the target mass number with the aim to get information on their width in the medium. They also demonstrate that both the A dependence of the relative {Lambda}(1520)-hyperon production cross section and momentum dependence of the absolute {Lambda}(1520)-hyperon yield at incident energy of interest are appreciably sensitive to the {Lambda}(1520) in-medium width, which means that these observables may be an important tool to determine the above width.
Lafferty, Kevin D.
Parasitism is the most popular life-style on Earth, and many vertebrates host more than one kind of parasite at a time. A common assumption is that parasite species rarely interact, because they often exploit different tissues in a host, and this use of discrete resources limits competition (1). On page 243 of this issue, however, Telfer et al. (2) provide a convincing case of a highly interactive parasite community in voles, and show how infection with one parasite can affect susceptibility to others. If some human parasites are equally interactive, our current, disease-by-disease approach to modeling and treating infectious diseases is inadequate (3).
... not be taken at the same time as antacids. WHAT CAUSES THE MOST INTERACTIONS WITH HIV MEDICATIONS? ... azole" Some antibiotics (names end in "mycin") The antacid cimetidine (Tagamet) Some drugs that prevent convulsions, including ...
Karsch, F.; Vogelsang, V.
We will give here an overview of our theory of the strong interactions, Quantum Chromo Dynamics (QCD) and its properties. We will also briefly review the history of the study of the strong interactions, and the discoveries that ultimately led to the formulation of QCD. The strong force is one of the four known fundamental forces in nature, the others being the electromagnetic, the weak and the gravitational force. The strong force, usually referred to by scientists as the 'strong interaction', is relevant at the subatomic level, where it is responsible for the binding of protons and neutrons to atomic nuclei. To do this, it must overcome the electric repulsion between the protons in an atomic nucleus and be the most powerful force over distances of a few fm (1fm=1 femtometer=1 fermi=10{sup -15}m), the typical size of a nucleus. This property gave the strong force its name.
DOE R&D Accomplishments Database
Lee, T. D.
Experimental results on the non-conservation of parity and charge conservation in weak interactions are reviewed. The two-component theory of the neutrino is discussed. Lepton reactions are examined under the assumption of the law of conservation of leptons and that the neutrino is described by a two- component theory. From the results of this examination, the universal Fermi interactions are analyzed. Although reactions involving the neutrino can be described, the same is not true of reactions which do not involve the lepton, as the discussion of the decay of K mesons and hyperons shows. The question of the invariance of time reversal is next examined. (J.S.R.)
ERIC Educational Resources Information Center
Boyce, Carol
A workshop on interactive video was designed for fourth and fifth grade students, with the goals of familiarizing students with laser disc technology, developing a cadre of trained students to train other students and staff, and challenging able learners to utilize higher level thinking skills while conducting a research project. (JDD)
ERIC Educational Resources Information Center
Martin, Jean K.
Presents guiding principles for developing interactive lessons for the World Wide Web. Describes "Amazing Space: Education Online from the Hubble Space Telescope", a program where students study spectacular Hubble Space Telescope images of stars and star-forming regions to learn about the life cycle of stars and the creation of atoms. (JRH)
ERIC Educational Resources Information Center
Riveros, Hector G.; Betancourt, Julian
The use of multiple compasses to map and visualize magnetic fields is well-known. The magnetic field exerts a torque on the compasses aligning them along the lines of force. Some science museums show the field of a magnet using a table with many compasses in a closely packed arrangement. However, the very interesting interactions that occur…
Putting Interaction into Interactive Television.
ERIC Educational Resources Information Center
Wolfe, Thomas E.
Current technology provides many new ideas and alternatives to traditional education and training practices. From the experience of the U.S. Air Force (USAF) Academic Instructor School (AIS) and current research in the field, teaching via interactive television (teleseminar/video teletraining) requires new teaching skills and new ways of thinking…
Schmidbaur, Hubert; Schier, Annette
The decade 1990-2000 saw a growing interest in aurophilic interactions in gold chemistry. These interactions were found to influence significantly a variety of structural and other physical characteristics of gold(I) compounds. The attention paid to this unusual and counterintuitive type of intra- and intermolecular bonding between seemingly closed-shell metal centers has rapidly been extended to also include silver chemistry. Hundreds of experimental and computational studies have since been dedicated to the argentophilicity phenomenon. The results of this development are reviewed herein focusing on molecular systems where two or more silver(I) centers are in close contact leading to specific structural characteristics and a variety of novel physical properties. These include strongly modified ligand-to-metal charge-transfer processes observed in absorption and emission spectroscopy, but also colossal positive and negative thermal expansion on the one hand and unprecedented negative linear compressibility of crystal parameters on the other. PMID:25393553
Renton, P.
The central part of the book consists of a comprehensive discussion of many scattering and decay processes involving electromagnetic, weak and strong interactions. A list of topics includes electron-proton scattering, Compton scattering, muon decay, electron-positron annihilation, photon and hadron structure functions, neutrino-nucleus scattering, Cabibbo theory, tau-lepton decays, W and Z boson decays, mixing phenomena and many others. For most processes, the author presents the appropriate Feynman diagrams, first-order matrix elements and the resulting cross sections or decay rates. The last section of Electroweak Interactions discusses some of the open or unanswered questions in the standard model, including the undiscovered top quark, the Higgs mechanism of electroweak symmetry breaking and detailed tests involving radiative effects. The book concludes with a brief account of ideas that extend beyond the standard model, such as left-right symmetric models, grand unified theories, compositeness, supersymmetry and string theory.
NASA Astrophysics Data System (ADS)
An image based on data taken with ESO's Very Large Telescope reveals a triplet of galaxies intertwined in a cosmic dance. ESO PR Photo 02/08 ESO PR Photo 02/08 NGC 7173, 7174, and 7176 The three galaxies, catalogued as NGC 7173 (top), 7174 (bottom right) and 7176 (bottom left), are located 106 million light-years away towards the constellation of Piscis Austrinus (the 'Southern Fish'). NGC 7173 and 7176 are elliptical galaxies, while NGC 7174 is a spiral galaxy with quite disturbed dust lanes and a long, twisted tail. This seems to indicate that the two bottom galaxies - whose combined shape bears some resemblance to that of a sleeping baby - are currently interacting, with NGC 7176 providing fresh material to NGC 7174. Matter present in great quantity around the triplet's members also points to the fact that NGC 7176 and NGC 7173 have interacted in the past. Astronomers have suggested that the three galaxies will finally merge into a giant 'island universe', tens to hundreds of times as massive as our own Milky Way. ESO PR Photo 02/08 ESO PR Photo 02b/08 NGC 7173, 7174, and 7176 The triplet is part of a so-called 'Compact Group', as compiled by Canadian astronomer Paul Hickson in the early 1980s. The group, which is the 90th entry in the catalogue and is therefore known as HCG 90, actually contains four major members. One of them - NGC 7192 - lies above the trio, outside of this image, and is another peculiar spiral galaxy. Compact groups are small, relatively isolated, systems of typically four to ten galaxies in close proximity to one another. Another striking example is Robert's Quartet. Compact groups are excellent laboratories for the study of galaxy interactions and their effects, in particular the formation of stars. As the striking image reveals, there are many other galaxies in the field. Some are distant ones, while others seem to be part of the family. Studies made with other telescopes have indeed revealed that the HCG 90 group contains 16 members
Designing "Interaction": How Do Interaction Design Students Address Interaction?
ERIC Educational Resources Information Center
Karlgren, Klas; Ramberg, Robert; Artman, Henrik
Interaction design is usually described as being concerned with interactions with and through artifacts but independent of a specific implementation. Design work has been characterized as a conversation between the designer and the situation and this conversation poses a particular challenge for interaction design as interactions can be elusive…
NASA Technical Reports Server (NTRS)
[figure removed for brevity, see original site]Released 1 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth. Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms. This image was acquired during mid-spring near the North Pole. The linear water-ice clouds are now regional in extent and often interact with neighboring cloud system, as seen in this image. The bottom of the image shows how the interaction can destroy the linear nature. While the surface is still visible through most of the clouds, there is evidence that dust is also starting to enter the atmosphere. Image information: VIS instrument. Latitude 68.4, Longitude 258.8 East (101.2 West). 38 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration
Pion single charge exchange in three body nuclei at intermediate energies
Dowell, M.L.
The purpose of this thesis is to present new experimental information about modifications to the pion-nucleon single charge exchange interaction, {pi}{sup +}n {yields}{pi}{sup 0} p or {pi}{sup {minus}} p {yields} {pi}{sup 0}n, due to the presence of other nucleons. The results of two experimental studies of pion single charge exchange in the three nucleon system near the {triangle}-resonance are presented. Both of these experiments were performed at the Clinton P. Anderson Meson Physics Facility (LAMPF), a division of the Los Alamos National Laboratory. Each explored different aspects of pion single charge exchange in three body nuclei--{sup 3}He and {sup 3}H. Since the nuclear wavefunctions of the three nucleon systems are believed to be well understood, it should be possible to perform theoretical calculations of pion interactions with this system and compare their predictions with the experimental results.
(Medium energy particle physics): Annual progress report
Nefkens, B.M.K.
Investigations currently carried out by the UCLA Particle Physics Research Group can be arranged into four programs: Pion-Nucleon Scattering; Tests of Charge Symmetry and Isospin Invariance; Light Nuclei (Strong Form Factors of /sup 3/H, /sup 3/He, /sup 4/He; Detailed Balance in pd /r reversible/ /gamma//sup 3/H; Interaction Dynamics); and Search for the Rare Decay /Mu//sup +/ /yields/ e/sup +/ + /gamma/ (MEGA). The general considerations which led to the choice of physics problems investigated by our group are given in the next section. We also outline the scope of the research being done which includes over a dozen experiments. The main body of this report details the research carried out in the past year, the status of various experiments, and new projects.
Perturbation theory for isotropic velocity-dependent potentials: scattering case
NASA Astrophysics Data System (ADS)
Jaghoub, Mahmoud
The time-independent Schr"odinger equation with an isotropic velocity-depen-dent potential is considered. Treating the velocity-dependent interaction as a small perturbation we develop analytical formulae for the changes in the scattering phase shifts and wave functions. It is shown that only the zeroth order solution and the perturbing potential are needed to determine the phase shift and wave function corrections. No prior knowledge of the unperturbed scattering states continuum is required. In order to test the validity of our approach we applied it to an exactly solvable model for nucleon-nucleon scattering. The results of the perturbation formalism compare quite well with the those of the exactly solvable model. The developed formalism can be applied in problems concerning pion-nucleon, nucleon-nucleon and electron-atom scattering. It may also be useful in studying the scattering of electrons in semiconductor heterostructures. )
Masses of Ground- and Excited-State Hadrons
NASA Astrophysics Data System (ADS)
Roberts, Hannes L. L.; Chang, Lei; Cloët, Ian C.; Roberts, Craig D.
We present the first Dyson-Schwinger equation calculation of the light hadron spectrum that simultaneously correlates the masses of meson and baryon ground- and excited-states within a single framework. At the core of our analysis is a symmetry-preserving treatment of a vector-vector contact interaction. In comparison with relevant quantities the root-mean-square-relative-error/degree-of freedom is 13%. Notable amongst our results is agreement between the computed baryon masses and the bare masses employed in modern dynamical coupled-channels models of pion-nucleon reactions. Our analysis provides insight into numerous aspects of baryon structure; e.g., relationships between the nucleon and Δ masses and those of the dressed-quark and diquark correlations they contain.
PIC: Protein Interactions Calculator.
Tina, K G; Bhadra, R; Srinivasan, N
Interactions within a protein structure and interactions between proteins in an assembly are essential considerations in understanding molecular basis of stability and functions of proteins and their complexes. There are several weak and strong interactions that render stability to a protein structure or an assembly. Protein Interactions Calculator (PIC) is a server which, given the coordinate set of 3D structure of a protein or an assembly, computes various interactions such as disulphide bonds, interactions between hydrophobic residues, ionic interactions, hydrogen bonds, aromatic-aromatic interactions, aromatic-sulphur interactions and cation-pi interactions within a protein or between proteins in a complex. Interactions are calculated on the basis of standard, published criteria. The identified interactions between residues can be visualized using a RasMol and Jmol interface. The advantage with PIC server is the easy availability of inter-residue interaction calculations in a single site. It also determines the accessible surface area and residue-depth, which is the distance of a residue from the surface of the protein. User can also recognize specific kind of interactions, such as apolar-apolar residue interactions or ionic interactions, that are formed between buried or exposed residues or near the surface or deep inside. PMID:17584791
Interacting dark sector with transversal interaction
Chimento, Luis P.; Richarte, Martín G.
We investigate the interacting dark sector composed of dark matter, dark energy, and dark radiation for a spatially flat Friedmann-Robertson-Walker (FRW) background by introducing a three-dimensional internal space spanned by the interaction vector Q and solve the source equation for a linear transversal interaction. Then, we explore a realistic model with dark matter coupled to a scalar field plus a decoupled radiation term, analyze the amount of dark energy in the radiation era and find that our model is consistent with the recent measurements of cosmic microwave background anisotropy coming from Planck along with the future constraints achievable by CMBPol experiment.
A Data Analysis Center for Electromagnetic and Hadronic Interaction. Products of the DAC members
Briscoe, William John; Strakovsky, Igor I.; Workman, Ronald L.
The Data Analysis Center (DAC) of the Center for Nuclear Studies (CNS) at the George Washington University (GW) has made significant progress in its program to enhance and expand the partial-wave (and multipole) analyses of fundamental two- and three-body reactions (such as pion-nucleon, photon-nucleon, and nucleon-nucleon scattering) by maintaining and augmenting the analysis codes and databases associated with these reactions. These efforts provide guidance to experimental groups at the international level, forming an important link between theory and experiment. A renaissance in light hadron spectroscopy is underway as a continuous stream of polarization data issues from existing precision electromagnetic facilities and the coming Jefferson Lab 12 GeV Upgrade. Our principal goals have been focused on supporting the national N* resonance physics program. We have also continued to study topics more generally related to the problems associated with partial-wave analysis. On the Experimental side of the CNS DAC. Its primary goal is the enhancement of the body of data necessary for our analyses of fundamental γ - N reactions. We perform experiments that study the dynamics responsible for the internal structure of the nucleon and its excitations. Our principal focus is on the N* programs at JLab and MAMI. At JLab we study spin-polarization observables using polarized photons, protons and neutrons and yielding charged final states. Similarly at MAMI we study neutral meson photoproduction off polarized protons and neutrons. We use the Crystal Ball and TAPS spectrometers (CBT) to detect photons and neutrons to measure the photoproduction of π0, η, 2π0, π0η, and K0 off the neutron. The CBT program complements our program at JLab, which studies reactions resulting in charged final states. We are also involved in a renewed effort to make neutral pion photoproduction measurements close to threshold at Mainz. In addition to the programs underway, we are contributing to
Interactivity: A Forgotten Art?
ERIC Educational Resources Information Center
Sims, Rod
This paper promotes further discussion and analysis of interactivity in learning environments and contains a classification of interaction types appropriate for consideration in multimedia settings. Through an examination of related factors associated with navigation and control, a matrix of interactive dimensions is proposed. (Author)
ERIC Educational Resources Information Center
Bennett, Audrey Grace
Based on a virtual conference, Glide'08 (Global Interaction in Design Education), that brought international design scholars together online, this special issue expands on the topics of cross-cultural communication and design and the technological affordances that support such interaction. The author discusses the need for global interaction in…
Evolving synergetic interactions
Wu, Bin; Arranz, Jordi; Du, Jinming; Zhou, Da; Traulsen, Arne
Cooperators forgo their own interests to benefit others. This reduces their fitness and thus cooperators are not likely to spread based on natural selection. Nonetheless, cooperation is widespread on every level of biological organization ranging from bacterial communities to human society. Mathematical models can help to explain under which circumstances cooperation evolves. Evolutionary game theory is a powerful mathematical tool to depict the interactions between cooperators and defectors. Classical models typically involve either pairwise interactions between individuals or a linear superposition of these interactions. For interactions within groups, however, synergetic effects may arise: their outcome is not just the sum of its parts. This is because the payoffs via a single group interaction can be different from the sum of any collection of two-player interactions. Assuming that all interactions start from pairs, how can such synergetic multiplayer games emerge from simpler pairwise interactions? Here, we present a mathematical model that captures the transition from pairwise interactions to synergetic multiplayer ones. We assume that different social groups have different breaking rates. We show that non-uniform breaking rates do foster the emergence of synergy, even though individuals always interact in pairs. Our work sheds new light on the mechanisms underlying such synergetic interactions. PMID:27466437
Evolving synergetic interactions.
Wu, Bin; Arranz, Jordi; Du, Jinming; Zhou, Da; Traulsen, Arne
Cooperators forgo their own interests to benefit others. This reduces their fitness and thus cooperators are not likely to spread based on natural selection. Nonetheless, cooperation is widespread on every level of biological organization ranging from bacterial communities to human society. Mathematical models can help to explain under which circumstances cooperation evolves. Evolutionary game theory is a powerful mathematical tool to depict the interactions between cooperators and defectors. Classical models typically involve either pairwise interactions between individuals or a linear superposition of these interactions. For interactions within groups, however, synergetic effects may arise: their outcome is not just the sum of its parts. This is because the payoffs via a single group interaction can be different from the sum of any collection of two-player interactions. Assuming that all interactions start from pairs, how can such synergetic multiplayer games emerge from simpler pairwise interactions? Here, we present a mathematical model that captures the transition from pairwise interactions to synergetic multiplayer ones. We assume that different social groups have different breaking rates. We show that non-uniform breaking rates do foster the emergence of synergy, even though individuals always interact in pairs. Our work sheds new light on the mechanisms underlying such synergetic interactions. PMID:27466437
Convergence in Multispecies Interactions.
Bittleston, Leonora S; Pierce, Naomi E; Ellison, Aaron M; Pringle, Anne
The concepts of convergent evolution and community convergence highlight how selective pressures can shape unrelated organisms or communities in similar ways. We propose a related concept, convergent interactions, to describe the independent evolution of multispecies interactions with similar physiological or ecological functions. A focus on convergent interactions clarifies how natural selection repeatedly favors particular kinds of associations among species. Characterizing convergent interactions in a comparative context is likely to facilitate prediction of the ecological roles of organisms (including microbes) in multispecies interactions and selective pressures acting in poorly understood or newly discovered multispecies systems. We illustrate the concept of convergent interactions with examples: vertebrates and their gut bacteria; ectomycorrhizae; insect-fungal-bacterial interactions; pitcher-plant food webs; and ants and ant-plants. PMID:26858111
DOE R&D Accomplishments Database
Salam, A.
Lectures with mathematical analysis are given on Dispersion Theory and Causality and Dispersion Relations for Pion-nucleon Scattering. The appendix includes the S-matrix in terms of Heisenberg Operators. (F. S.)
Isospin Breaking in the Goldberger-Treiman Discrepancies
Jose Goity; Jordi Saez
Effects of isospin breaking at the level of the Goldberger-Treiman discrepancies involving the neutral isotriplet axial and pion-nucleon couplings are analyzed to leading non-trivial order in chiral perturbation theory.
The Interactive Learning Toolkit: supporting interactive classrooms
NASA Astrophysics Data System (ADS)
Dutta, S.; McCauley, V.; Mazur, E.
Research-based interactive learning techniques have dramatically improved student understanding. We have created the 'Interactive Learning Toolkit' (ILT), a web-based learning management system, to help implement two such pedagogies: Just in Time Teaching and Peer Instruction. Our main goal in developing this toolkit is to save the instructor time and effort and to use technology to facilitate the interaction between the students and the instructor (and between students themselves). After a brief review of both pedagogies, we will demonstrate the many exciting new features of the ILT. We will show how technology can not only implement, but also supplement and improve these pedagogies. We would like acknowdge grants from NSF and DEAS, Harvard University
Antiplatelet drug interactions.
Mackenzie, I S; Coughtrie, M W H; MacDonald, T M; Wei, L
Both laboratory studies in healthy volunteers and clinical studies have suggested adverse interactions between antiplatelet drugs and other commonly used medications. Interactions described include those between aspirin and ibuprofen, aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), and the thienopyridine, clopidogrel, and drugs inhibiting CYP2C19, notably the proton pump inhibitors (PPI) omeprazole and esomeprazole. Other interactions between thienopyridines and CYP3A4/5 have also been reported for statins and calcium channel blockers. The ibuprofen/aspirin interaction is thought to be caused by ibuprofen blocking the access of aspirin to platelet cyclo-oxygenase. The thienopyridine interactions are caused by inhibition of microsomal enzymes that metabolize these pro-drugs to their active metabolites. We review the evidence for these interactions, assess their clinical importance and suggest strategies of how to deal with them in clinical practice. We conclude that ibuprofen is likely to interact with aspirin and reduce its anti-platelet action particularly in those patients who take ibuprofen chronically. This interaction is of greater relevance to those patients at high cardiovascular risk. A sensible strategy is to advise users of aspirin to avoid chronic ibuprofen or to ingest aspirin at least 2 h prior to ibuprofen. Clearly the use of NSAIDs that do not interact in this way is preferred. For the clopidogrel CYP2C19 and CYP3A4/5 interactions, there is good evidence that these interactions occur. However, there is less good evidence to support the clinical importance of these interactions. Again, a reasonable strategy is to avoid the chronic use of drugs that inhibit CYP2C19, notably PPIs, in subjects taking clopidogrel and use high dose H2 antagonists instead. Finally, anti-platelet agents probably interact with other drugs that affect platelet function such as selective serotonin reuptake inhibitors, and clinicians should probably judge
The interactive brain hypothesis
Di Paolo, Ezequiel; De Jaegher, Hanne
Enactive approaches foreground the role of interpersonal interaction in explanations of social understanding. This motivates, in combination with a recent interest in neuroscientific studies involving actual interactions, the question of how interactive processes relate to neural mechanisms involved in social understanding. We introduce the Interactive Brain Hypothesis (IBH) in order to help map the spectrum of possible relations between social interaction and neural processes. The hypothesis states that interactive experience and skills play enabling roles in both the development and current function of social brain mechanisms, even in cases where social understanding happens in the absence of immediate interaction. We examine the plausibility of this hypothesis against developmental and neurobiological evidence and contrast it with the widespread assumption that mindreading is crucial to all social cognition. We describe the elements of social interaction that bear most directly on this hypothesis and discuss the empirical possibilities open to social neuroscience. We propose that the link between coordination dynamics and social understanding can be best grasped by studying transitions between states of coordination. These transitions form part of the self-organization of interaction processes that characterize the dynamics of social engagement. The patterns and synergies of this self-organization help explain how individuals understand each other. Various possibilities for role-taking emerge during interaction, determining a spectrum of participation. This view contrasts sharply with the observational stance that has guided research in social neuroscience until recently. We also introduce the concept of readiness to interact to describe the practices and dispositions that are summoned in situations of social significance (even if not interactive). This latter idea links interactive factors to more classical observational scenarios. PMID:22701412
Kim, Hyung Jin; /Fermilab
In high energy storage-ring colliders, the nonlinear effect arising from beam-beam interactions is a major source that leads to the emittance growth, the reduction of beam life time, and limits the collider luminosity. In this paper, two models of beam-beam interactions are introduced, which are weak-strong and strong-strong beam-beam interactions. In addition, space-charge model is introduced.
Bushra, Rabia; Aslam, Nousheen; Khan, Arshad Yar
The effect of drug on a person may be different than expected because that drug interacts with another drug the person is taking (drug-drug interaction), food, beverages, dietary supplements the person is consuming (drug-nutrient/food interaction) or another disease the person has (drug-disease interaction). A drug interaction is a situation in which a substance affects the activity of a drug, i.e. the effects are increased or decreased, or they produce a new effect that neither produces on its own. These interactions may occur out of accidental misuse or due to lack of knowledge about the active ingredients involved in the relevant substances. Regarding food-drug interactions physicians and pharmacists recognize that some foods and drugs, when taken simultaneously, can alter the body's ability to utilize a particular food or drug, or cause serious side effects. Clinically significant drug interactions, which pose potential harm to the patient, may result from changes in pharmaceutical, pharmacokinetic, or pharmacodynamic properties. Some may be taken advantage of, to the benefit of patients, but more commonly drug interactions result in adverse drug events. Therefore it is advisable for patients to follow the physician and doctors instructions to obtain maximum benefits with least food-drug interactions. The literature survey was conducted by extracting data from different review and original articles on general or specific drug interactions with food. This review gives information about various interactions between different foods and drugs and will help physicians and pharmacists prescribe drugs cautiously with only suitable food supplement to get maximum benefit for the patient. PMID:22043389
Pike, William A.; Stasko, John T.; Chang, Remco; O'Connell, Theresa
There is a growing recognition with the visual analytics community that interaction and inquiry are inextricable. It is through the interactive manipulation of a visual interface – the analytic discourse – that knowledge is constructed, tested, refined, and shared. This paper reflects on the interaction challenges raised in the original visual analytics research and development agenda and further explores the relationship between interaction and cognition. It identifies recent exemplars of visual analytics research that have made substantive progress toward the goals of a true science of interaction, which must include theories and testable premises about the most appropriate mechanisms for human-information interaction. Six areas for further work are highlighted as those among the highest priorities for the next five years of visual analytics research: ubiquitous, embodied interaction; capturing user intentionality; knowledge-based interfaces; principles of design and perception; collaboration; and interoperability. Ultimately, the goal of a science of interaction is to support the visual analytics community through the recognition and implementation of best practices in the representation of and interaction with visual displays.
Scott, A.C.
Some recent experimental and theoretical results on mechanisms through which individual nerve pulses can interact are reviewed. Three modes of interactions are considered: (1) interaction of pulses as they travel along a single fiber which leads to velocity dispersion; (2) propagation of pairs of pulses through a branching region leading to quantum pulse code transformations; and (3) interaction of pulses on parallel fibers through which they may form a pulse assembly. This notion is analogous to Hebb's concept of a cell assembly, but on a lower level of the neural hierarchy.
Interactive brains, social minds.
Sänger, Johanna; Lindenberger, Ulman; Müller, Viktor
To reveal the neural and behavioral dynamics of social interaction, single-person studies are increasingly complemented by research designs that simultaneously assess two or more interacting individuals. In this article, we review studies on neural mechanisms and markers of social interactions that use multi-person functional magnetic resonance imaging and electrophysiological recordings. We propose a terminology for investigating social interaction dynamics, show how forward models of action regulation may serve as a framework for investigating interpersonal action coordination and discuss different methodological approaches to studying functional brain connectivity. PMID:22448303
Two interacting Hofstadter butterflies
Barelli, A.; Bellissard, J.; Jacquod, P.; Shepelyansky, D.L.
The problem of two interacting particles in a quasiperiodic potential is addressed. Using analytical and numerical methods, we explore the spectral properties and eigenstates structure from the weak to the strong interaction case. More precisely, a semiclassical approach based on noncommutative geometry techniques is used to understand the intricate structure of such a spectrum. An interaction induced localization effect is furthermore emphasized. We discuss the application of our results on a two-dimensional model of two particles in a uniform magnetic field with on-site interaction. {copyright} {ital 1997} {ital The American Physical Society}
Interactive brains, social minds
Lindenberger, Ulman
To reveal the neural and behavioral dynamics of social interaction, single-person studies are increasingly complemented by research designs that simultaneously assess two or more interacting individuals. In this article, we review studies on neural mechanisms and markers of social interactions that use multi-person functional magnetic resonance imaging and electrophysiological recordings. We propose a terminology for investigating social interaction dynamics, show how forward models of action regulation may serve as a framework for investigating interpersonal action coordination and discuss different methodological approaches to studying functional brain connectivity. PMID:22448303
Reconceptualizing sex, brain and psychopathology: interaction, interaction, interaction
Joel, D; Yankelevitch-Yahav, R
In recent years there has been a growing recognition of the influence of sex on brain structure and function, and in relation, on the susceptibility, prevalence and response to treatment of psychiatric disorders. Most theories and descriptions of the effects of sex on the brain are dominated by an analogy to the current interpretation of the effects of sex on the reproductive system, according to which sex is a divergence system that exerts a unitary, overriding and serial effect on the form of other systems. We shortly summarize different lines of evidence that contradict aspects of this analogy. The new view that emerges from these data is of sex as a complex system whose different components interact with one another and with other systems to affect body and brain. The paradigm shift that this understanding calls for is from thinking of sex in terms of sexual dimorphism and sex differences, to thinking of sex in terms of its interactions with other factors and processes. Our review of data obtained from animal models of psychopathology clearly reveals the need for such a paradigmatic shift, because in the field of animal behaviour whether a sex difference exists and its direction depend on the interaction of many factors including, species, strain, age, specific test employed and a multitude of environmental factors. We conclude by explaining how the new conceptualization can account for sex differences in psychopathology. Linked Articles This article is part of a themed section on Animal Models in Psychiatry Research. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-20 PMID:24758640
Visualizing Dispersion Interactions
ERIC Educational Resources Information Center
Gottschalk, Elinor; Venkataraman, Bhawani
An animation and accompanying activity has been developed to help students visualize how dispersion interactions arise. The animation uses the gecko's ability to walk on vertical surfaces to illustrate how dispersion interactions play a role in macroscale outcomes. Assessment of student learning reveals that students were able to develop…
The Interaction Equivalency Theorem
ERIC Educational Resources Information Center
Miyazoe, Terumi; Anderson, Terry
This paper examines the key issues regarding The Interaction Equivalency Theorem posited by Anderson (2003a), which consists of the three interaction elements found in formal education courses among teacher, student, and content. It first examines the core concepts of the theorem and argues that two theses of different dimensions can be…
ERIC Educational Resources Information Center
Brown, Eric
Examines the future of interactive TV where consumers navigate the Internet on their TVs with WebTV set-top boxes. Focuses on competition between cable companies and computer and consumer electronics companies. Highlights nine companies and partnerships developing interactive hardware and services. (PEN)
Newseum: Open for Interaction.
ERIC Educational Resources Information Center
Luck, Brad
Describes a teenage journalist's visit to the Newseum in Washington, DC, the world's only interactive museum dedicated to news. Describes visiting the Interactive Newsroom, the huge News Globe, the News History Gallery, and the Broadcast Studio. Describes also a brief visit to Freedom Park and the Newseum Education Center. Notes the enthusiasm of…
Interactive Presentation of Content
ERIC Educational Resources Information Center
Magdin, Martin; Turcáni, Milan; Vrábel, Marek
In the paper we discus about design of universal environment for solution of creating effective multimedia applications with accent on the implementation of interactive elements with the possibility of using the adaptive systems (AS). We also discuss about possibilities of offline presentation of this interactive multimedia adaptive animations…
ERIC Educational Resources Information Center
Smuts, Aaron
In this article, the author attempts to develop a definition of "interactivity" that meets two sometimes incompatible goals: the definition should be in accord with the best intuitions on how the term should be used, and it should usefully differentiate interactivity from related but incompatible concepts with which it is often confused. The…
NASA Astrophysics Data System (ADS)
Infrared Space Observatory (ISO) Development Team
The Long Wavelength Spectrometer (LWS) was one of two complementary spectrometers on the Infrared Space Observatory (ISO). LIA (LWS Interactive Analysis) is used for processing data from the LWS. It provides access to the different processing steps, including visualization of intermediate products and interactive manipulation of the data at each stage.
Interactive Videodisc Learning Systems.
ERIC Educational Resources Information Center
Currier, Richard L.
Interactive videodisc makes possible a powerful educational experience in which computer-based educational systems can display video imagery, real-time action, and stereo sound. Interactivity, teaching with videodisc, electronic tutors, videodisc technologies, and costs are among the topics discussed. Use of videodisc for games and simulating…
Oral contraceptive drug interactions.
Baciewicz, A M
Approximately 50 million women use oral contraceptives (OC). Studies and case reports demonstrate that OC failure may be caused by rifampin, anticonvulsant drugs, and possibly some antibiotics. Contraceptive steroids may interfere with the metabolism of the benzodiazepines, theophylline, and the glucocorticoids. Future investigation will document the clinical significance of other OC interactions as well as give rise to new interactions. PMID:2859674
Interactive Visualization of Dependencies
ERIC Educational Resources Information Center
Moreno, Camilo Arango; Bischof, Walter F.; Hoover, H. James
We present an interactive tool for browsing course requisites as a case study of dependency visualization. This tool uses multiple interactive visualizations to allow the user to explore the dependencies between courses. A usability study revealed that the proposed browser provides significant advantages over traditional methods, in terms of…
University-industry interaction
NASA Technical Reports Server (NTRS)
Hastings, Daniel E.
It is posited that university industry interaction is highly desirable from the viewpoint of the long term economic development of the country as well as being desirable for the Space Grant Programs. The present and future possible interactions are reviewed for the three university levels namely, undergraduate, graduate, and faculty research.
ERIC Educational Resources Information Center
Johnson, J. David
A review of literature and two surveys, one of college students and one of a random sample of adults, were used to examine four aspects of media embedded interactions (social behavior in front of a TV or radio): their functions, their environment, their effects, and the reactions of the interactants to them. Television is seen as performing a…
Let Social Interaction Flourish
ERIC Educational Resources Information Center
Case, Anny Fritzen
The author describes lessons learned--through a high school project that grouped English language learners with native speakers to create a video--about ways to foster respectful, productive interaction among English learners and peers who are native speakers. The potential benefits of students who are just learning English interacting socially…
NASA Technical Reports Server (NTRS)
The results of the third and final phase of a study undertaken to define means of optimizing the Spacelab experiment data system by interactively manipulating the flow of data were presented. A number of payload applicable interactive techniques and an integrated interaction system for each of two possible payloads are described. These interaction systems have been functionally defined and are accompanied with block diagrams, hardware specifications, software sizing and speed requirements, operational procedures and cost/benefits analysis data for both onboard and ground based system elements. It is shown that accrued benefits are attributable to a reduction in data processing costs obtained by, generally, a considerable reduction in the quantity of data that might otherwise be generated without interaction. One other additional anticipated benefit includes the increased scientific value obtained by the quicker return of all useful data.
Legacy Systems Interaction Reengineering
NASA Astrophysics Data System (ADS)
El-Ramly, Mohammad; Stroulia, Eleni; Samir, Hani
We present a lightweight approach for reengineering the human computer interaction (HCI) and/or interaction with other software systems. While interaction reengineering can be achieved by changing the source code and design (e.g., library replacement, refactoring, etc.) resulting in a different user interface (UI), we limit the discussion to interaction reengineering methods that do not involve changing the source code or internal design of the system. Instead, we focus on methods and techniques for wrapping and packaging the existing interaction layer to reproduce it in a different format, e.g., on a different platform or to integrate the legacy system services in another application possibly under a different architecture paradigm, e.g., service-oriented architectures (SOA).
NASA Technical Reports Server (NTRS)
Ferguson, Dale C.
Photovoltaic arrays interact with the low earth orbit (LEO) space plasma in two fundamentally different ways. One way is the steady collection of current from the plasma onto exposed conductors and semiconductors. The relative currents collected by different parts of the array will then determine the floating potential of the spacecraft. In addition, these steady state collected currents may lead to sputtering or heating of the array by the ions or electrons collected, respectively. The second kind of interaction is the short time scale arc into the space plasma, which may deplete the array and/or spacecraft of stored charge, damage solar cells, and produce EMI. Such arcs only occur at high negative potentials relative to the space plasma potential, and depend on the steady state ion currents being collected. New high voltage solar arrays being incorporated into advanced spacecraft and space platforms may be endangered by these plasma interactions. Recent advances in laboratory testing and current collection modeling promise the capability of controlling, and perhaps even using, these space plasma interactions to enable design of reliable high voltage space power systems. Some of the new results may have an impact on solar cell spacing and/or coverslide design. Planned space flight experiments are necessary to confirm the models of high voltage solar array plasma interactions. Finally, computerized, integrated plasma interactions design tools are being constructed to place plasma interactions models into the hands of the spacecraft designer.
Becker, Daniel E.
The potential for interactions with current medications should always be considered when administering or prescribing any drug. Considering the staggering number of drugs patients may be taking, this task can be daunting. Fortunately, drug classes employed in dental practice are relatively few in number and therapy is generally brief in duration. While this reduces the volume of potential interactions, there are still a significant number to be considered. This article will review basic principles of drug interactions and highlight those of greatest concern in dental practice. PMID:21410363
The ADAMS interactive interpreter
Rietscha, E.R.
The ADAMS (Advanced DAta Management System) project is exploring next generation database technology. Database management does not follow the usual programming paradigm. Instead, the database dictionary provides an additional name space environment that should be interactively created and tested before writing application code. This document describes the implementation and operation of the ADAMS Interpreter, an interactive interface to the ADAMS data dictionary and runtime system. The Interpreter executes individual statements of the ADAMS Interface Language, providing a fast, interactive mechanism to define and access persistent databases. 5 refs.
Interactive Office user's manual
NASA Technical Reports Server (NTRS)
Montgomery, Edward E.; Lowers, Benjamin; Nabors, Terri L.
Given here is a user's manual for Interactive Office (IO), an executive office tool for organization and planning, written specifically for Macintosh. IO is a paperless management tool to automate a related group of individuals into one productive system.
NASA Astrophysics Data System (ADS)
Hasenkamp, Jasper
We propose a theory that equips the active neutrinos with interactions among themselves that are at least 3 orders of magnitude stronger than the weak interaction. We introduce an Abelian gauge group U (1 )X with vacuum expectation value vx≲O (100 MeV ) . An asymmetric mass matrix implements the active neutrinos as massless mass eigenstates carrying "effective" charges. To stabilize vx, supersymmetry breaking is mediated via loops to the additional sector with the only exception of xHiggs terms. No Standard Model interaction eigenstate carries U (1 )X charge. Thus, the dark photon's kinetic mixing is two-loop suppressed. With only simple and generic values of dimensionless parameters, our theory might explain the high-energy neutrino spectrum observed by IceCube including the PeV neutrinos. We comment on the imposing opportunity to incorporate a self-interacting dark matter candidate.
Atomic & Molecular Interactions
The Gordon Research Conference (GRC) on Atomic & Molecular Interactions was held at Roger Williams University, Bristol, RI. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.
Grapefruit and drug interactions.
Since the late 1980s, grapefruit juice has been known to affect the metabolism of certain drugs. Several serious adverse effects involving drug interactions with grapefruit juice have been published in detail. The components of grapefruit juice vary considerably depending on the variety, maturity and origin of the fruit, local climatic conditions, and the manufacturing process. No single component accounts for all observed interactions. Other grapefruit products are also occasionally implicated, including preserves, lyophylised grapefruit juice, powdered whole grapefruit, grapefruit seed extract, and zest. Clinical reports of drug interactions with grapefruit juice are supported by pharmacokinetic studies, each usually involving about 10 healthy volunteers, in which the probable clinical consequences were extrapolated from the observed plasma concentrations. Grapefruit juice inhibits CYP3A4, the cytochrome P450 isoenzyme most often involved in drug metabolism. This increases plasma concentrations of the drugs concerned, creating a risk of overdose and dose-dependent adverse effects. Grapefruit juice also inhibits several other cytochrome P450 isoenzymes, but they are less frequently implicated in interactions with clinical consequences. Drugs interacting with grapefruit and inducing serious clinical consequences (confirmed or very probable) include: immunosuppressants, some statins, benzodiazepines, most calcium channel blockers, indinavir and carbamazepine. There are large inter-individual differences in enzyme efficiency. Along with the variable composition of grapefruit juice, this makes it difficult to predict the magnitude and clinical consequences of drug interactions with grapefruit juice in a given patient. There is increasing evidence that transporter proteins such as organic anion transporters and P-glycoprotein are involved in interactions between drugs and grapefruit juice. In practice, numerous drugs interact with grapefruit juice. Although only a few
Interaction: Additivity plus Nonlinearity?
ERIC Educational Resources Information Center
Hutchinson, T. P.
Whether or not there is an interaction between two factors in their effects on a dependent variable is often a central question. This paper proposes a general mechanism by which an interaction may arise: (a) the two factors are the same thing--or, at least, have a dimension in common--in the sense that it is meaningful to add (or subtract) them;…
Asymptotically Safe Weak Interactions
NASA Astrophysics Data System (ADS)
Calmet, Xavier
We emphasize that the electroweak interactions without a Higgs boson are very similar to quantum general relativity. The Higgs field could just be a dressing field and might not exist as a propagating particle. In that interpretation, the electroweak interactions without a Higgs boson could be renormalizable at the nonperturbative level because of a nontrivial fixed point. Tree-level unitarity in electroweak bosons scattering is restored by the running of the weak scale.
NASA Technical Reports Server (NTRS)
Preheim, Larry E.; Amy, Laraine; Young, Jimmie D.
Interactive DIF Generator (IDG) computer program serves as utility to generate and manipulate directory interchange format (DIF) files. Creates and updates DIF files, sent to NASA's Master Directory, also referred to as International Global Change Directory at Goddard Space Flight Center. Many government and university data systems use Master Directory to advertise availability of research data. IDG is interactive software tool and requires mouse or trackball to operate. Written in C language.
NASA Technical Reports Server (NTRS)
Moses, Stewart L.; Greenstadt, Eugene W.; Coroniti, Ferdinand V.
In this report we will summarize the results of the work performed under the 'Flank Solar Wind Interaction' investigation in support of NASA's Space Physics Guest Investigator Program. While this investigation was focused on the interaction of the Earth's magnetosphere with the solar wind as observed by instruments on the International Sun-Earth Explorer (ISEE) 3 spacecraft, it also represents the culmination of decades of research performed by scientists at TRW on the rich phenomenology of collisionless shocks in space.
Consistent interactions and involution
NASA Astrophysics Data System (ADS)
Kaparulin, D. S.; Lyakhovich, S. L.; Sharapov, A. A.
Starting from the concept of involution of field equations, a universal method is proposed for constructing consistent interactions between the fields. The method equally well applies to the Lagrangian and non-Lagrangian equations and it is explicitly covariant. No auxiliary fields are introduced. The equations may have (or have no) gauge symmetry and/or second class constraints in Hamiltonian formalism, providing the theory admits a Hamiltonian description. In every case the method identifies all the consistent interactions.
PIA: ISOPHOT Interactive Analysis
NASA Astrophysics Data System (ADS)
Gabriel, Carlos; Acosta, Jose; Heinrichsen, Ingolf; Skaley, Detlef; Tai, Wai Ming; Morris, Huw; Merluzzi, Paola
ISOPHOT is one of the instruments on board the Infrared Space Observatory (ISO). ISOPHOT Interactive Analysis (PIA) is a scientific and calibration interactive data analysis tool for ISOPHOT data reduction. Written in IDL under Xwindows, PIA offers a full context sensitive graphical interface for retrieving, accessing and analyzing ISOPHOT data. It is available in two nearly identical versions; a general observers version omits the calibration sequences.
Forsythe, J. Chris; Xavier, Patrick G.; Abbott, Robert G.; Brannon, Nathan G.; Bernard, Michael L.; Speed, Ann E.
Digital technology utilizing a cognitive model based on human naturalistic decision-making processes, including pattern recognition and episodic memory, can reduce the dependency of human-machine interactions on the abilities of a human user and can enable a machine to more closely emulate human-like responses. Such a cognitive model can enable digital technology to use cognitive capacities fundamental to human-like communication and cooperation to interact with humans.
Adverse antibiotic drug interactions.
Bint, A J; Burtt, I
There is enormous potential for drug interactions in patients who, today, often receive many drugs. Antibiotics are prominent amongst the groups of drugs commonly prescribed. Many interactions take place at the absorption stage. Antacids and antidiarrhoeal preparations, in particular, can delay and reduce the absorption of antibiotics such as tetracyclines and clindamycin, by combining with them in the gastrointestinal tract to form chelates or complexes. Other drugs can affect gastric motility, which in turn often controls the rate at which antibiotics are absorbed. Some broad spectrum antibiotics can alter the bacterial flora of the gut which may be related to malabsorption states. The potentiation of toxic side effects of one drug by another is a common type of interaction. Antibiotics which are implicated in this type of interaction are those which themselves possess some toxicity such as aminoglycosides, some cephalosporins, tetracyclines and colistin. Some of the most important adverse interactions with antibiotics are those which involve other drugs which have a low toxicity/efficacy ratio. These include anticoagulants such as warfarin, anticonvulsants such as phenytoin and phenobarbitone and oral antidiabetic drugs like tolbutamide. Risk of interaction arises when the metabolism of these drugs is inhibited by liver microsomal enzyme inhibitors such as some sulphonamides and chloramphenicol, or is enhanced by enzyme inducers such as rifampicin. PMID:6995091
Interaction with Machine Improvisation
NASA Astrophysics Data System (ADS)
Assayag, Gerard; Bloch, George; Cont, Arshia; Dubnov, Shlomo
We describe two multi-agent architectures for an improvisation oriented musician-machine interaction systems that learn in real time from human performers. The improvisation kernel is based on sequence modeling and statistical learning. We present two frameworks of interaction with this kernel. In the first, the stylistic interaction is guided by a human operator in front of an interactive computer environment. In the second framework, the stylistic interaction is delegated to machine intelligence and therefore, knowledge propagation and decision are taken care of by the computer alone. The first framework involves a hybrid architecture using two popular composition/performance environments, Max and OpenMusic, that are put to work and communicate together, each one handling the process at a different time/memory scale. The second framework shares the same representational schemes with the first but uses an Active Learning architecture based on collaborative, competitive and memory-based learning to handle stylistic interactions. Both systems are capable of processing real-time audio/video as well as MIDI. After discussing the general cognitive background of improvisation practices, the statistical modelling tools and the concurrent agent architecture are presented. Then, an Active Learning scheme is described and considered in terms of using different improvisation regimes for improvisation planning. Finally, we provide more details about the different system implementations and describe several performances with the system.
Nonadditivity of nanoparticle interactions.
Batista, Carlos A Silvera; Larson, Ronald G; Kotov, Nicholas A
Understanding interactions between inorganic nanoparticles (NPs) is central to comprehension of self-organization processes and a wide spectrum of physical, chemical, and biological phenomena. However, quantitative description of the interparticle forces is complicated by many obstacles that are not present, or not as severe, for microsize particles (μPs). Here we analyze the sources of these difficulties and chart a course for future research. Such difficulties can be traced to the increased importance of discreteness and fluctuations around NPs (relative to μPs) and to multiscale collective effects. Although these problems can be partially overcome by modifying classical theories for colloidal interactions, such an approach fails to manage the nonadditivity of electrostatic, van der Waals, hydrophobic, and other interactions at the nanoscale. Several heuristic rules identified here can be helpful for discriminating between additive and nonadditive nanoscale systems. Further work on NP interactions would benefit from embracing NPs as strongly correlated reconfigurable systems with diverse physical elements and multiscale coupling processes, which will require new experimental and theoretical tools. Meanwhile, the similarity between the size of medium constituents and NPs makes atomic simulations of their interactions increasingly practical. Evolving experimental tools can stimulate improvement of existing force fields. New scientific opportunities for a better understanding of the electronic origin of classical interactions are converging at the scale of NPs. PMID:26450215
Interactions between photodegradation components
Background The interactions of p-cresol photocatalytic degradation components were studied by response surface methodology. The study was designed by central composite design using the irradiation time, pH, the amount of photocatalyst and the p-cresol concentration as variables. The design was performed to obtain photodegradation % as actual responses. The actual responses were fitted with linear, two factor interactions, cubic and quadratic model to select an appropriate model. The selected model was validated by analysis of variance which provided evidences such as high F-value (845.09), very low P-value (<.0.0001), non-significant lack of fit, the coefficient of R-squared (R2 = 0.999), adjusted R-squared (Radj2 = 0.998), predicted R-squared (Rpred2 = 0.994) and the adequate precision (95.94). Results From the validated model demonstrated that the component had interaction with irradiation time under 180 min of the time while the interaction with pH was above pH 9. Moreover, photocatalyst and p-cresol had interaction at minimal amount of photocatalyst (< 0.8 g/L) and 100 mg/L p-cresol. Conclusion These variables are interdependent and should be simultaneously considered during the photodegradation process, which is one of the advantages of the response surface methodology over the traditional laboratory method. PMID:22967885
Phonons and their interactions
Nicklow, R.M.
The phonon energy spectra nu(vector q) of crystalline materials contains key information about the interatomic interactions. However, it is generally not possible to fully understand the phonon spectra without also understanding the influence on phonon energies and lifetimes caused by interactions with defects, electrons and other excitations. The study of several of these types of interactions have grown over the years so as to now constitute subfields of solid state physics and the contributions of neutron scattering research to each has been, if not of paramount importance, at least very significant. In the present review we can merely touch on a few highlights. Perhaps the largest research effort is expended on electron-phonon interactions. These interactions are, of course, fundamental to the properties of metallic solids. They are seen in the phonon nu(vector q) of metals in a wide variety of effects. We shall mention three: the relatively small fine structure produced by Kohn singularities, large anomalies and phonon lifetimes measured in some superconductors and in materials with fluctuating valence.
Propeller tip vortex interactions
NASA Technical Reports Server (NTRS)
Johnston, Robert T.; Sullivan, John P.
Propeller wakes interacting with aircraft aerodynamic surfaces are a source of noise and vibration. For this reason, flow visualization work on the motion of the helical tip vortex over a wing and through the second stage of a counterrotation propeller (CRP) has been pursued. Initially, work was done on the motion of a propeller helix as it passes over the center of a 9.0 aspect ratio wing. The propeller tip vortex experiences significant spanwise displacements when passing across a lifting wing. A stationary propeller blade or stator was installed behind the rotating propeller to model the blade vortex interaction in a CRP. The resulting vortex interaction was found to depend on the relative vortex strengths and vortex sign.
DOE R&D Accomplishments Database
Lee, T. D.
While the phenomenon of beta-decay was discovered near the end of the last century, the notion that the weak interaction forms a separate field of physical forces evolved rather gradually. This became clear only after the experimental discoveries of other weak reactions such as muon-decay, muon-capture, etc., and the theoretical observation that all these reactions can be described by approximately the same coupling constant, thus giving rise to the notion of a universal weak interaction. Only then did one slowly recognize that the weak interaction force forms an independent field, perhaps on the same footing as the gravitational force, the electromagnetic force, and the strong nuclear and sub-nuclear forces.
E. Gaffiney
This report presents and documents the model components and analyses that represent potential processes associated with propagation of a magma-filled crack (dike) migrating upward toward the surface, intersection of the dike with repository drifts, flow of magma in the drifts, and post-magma emplacement effects on repository performance. The processes that describe upward migration of a dike and magma flow down the drift are referred to as the dike intrusion submodel. The post-magma emplacement processes are referred to as the post-intrusion submodel. Collectively, these submodels are referred to as a conceptual model for dike/drift interaction. The model components and analyses of the dike/drift interaction conceptual model provide the technical basis for assessing the potential impacts of an igneous intrusion on repository performance, including those features, events, and processes (FEPs) related to dike/drift interaction (Section 6.1).
Dynamics of Galaxy Interactions
NASA Astrophysics Data System (ADS)
Barnes, Joshua E.
Preface Theory of Interacting Galaxies The Role of Gravity Holmberg's Work on Tidal Interactions "Galactic Bridges and Tails" Dark Matter Numerical Stellar Dynamics Collisionless Stellar Systems Simulating the Stars Force Calculation Time Integration Errors and Relaxation Effects Initial Conditions Numerical Gas Dynamics A Sketch of the Interstellar Medium Simulating the ISM Gas in B/D/H Models Tidal Interactions Test-Particle Studies: Bridges and Tails Self-Consistent Studies Bars and Spirals Tidal Dwarf Galaxies Self-Consistent "Lookalikes" Getting the Feel of the Antennae Sneaking Up on the Mice What Happened to the Whirlpool? Unresolved Issues Mechanics of Merging Tidal Drag Orbit Decay Violent Relaxation Final Encounters Remnant Structure Phase Mixing Characteristics Scales Radial Profiles Shapes and Kinematics Orbit Structure Gas Dynamics in Mergers Inflows in Perturbed Disks Merging Encounters Remnant Structure Dissipation and Stellar Backlash Galaxy transformation and the Arrow of Time
Achromatic Interaction Point Design
Guimei Wang,, Yaroslav Derbenev, S.Alex Bogacz, P. Chevtsov, Andre Afanaciev, Charles Ankenbrandt, Valentin Ivanov, Rolland P. Johnson
Designers of high-luminosity energy-frontier muon colliders must provide strong beam focusing in the interaction regions. However, the construction of a strong, aberration-free beam focus is difficult and space consuming, and long straight sections generate an off-site radiation problem due to muon decay neutrinos that interact as they leave the surface of the earth. Without some way to mitigate the neutrino radiation problem, the maximum c.m. energy of a muon collider will be limited to about 3.5 TeV. A new concept for achromatic low beta design is being developed, in which the interaction region telescope and optical correction elements, are installed in the bending arcs. The concept, formulated analytically, combines space economy, a preventative approach to compensation for aberrations, and a reduction of neutrino flux concentration. An analytical theory for the aberration-free, low beta, spatially compact insertion is being developed.
Carotenoid-Protein Interactions
NASA Astrophysics Data System (ADS)
Britton, George; Helliwell, John R.
Chapter 5 shows that the aggregation of carotenoid molecules can have a profound effect on their properties and hence their functioning in biological systems. Another important influence is the interaction between carotenoids and other molecules. The way that interactions of carotenoids with lipid bilayers influence the structure and properties of membranes and membrane-asociated processes is discussed in Chapter 10, and the aggregation of carotenoid molecules within the bilayers in Chapter 5. Of particular importance, though, are interactions between carotenoids and proteins. These allow the hydrophobic carotenoids to be transported, to exist, and to function in an aqueous environment. In some cases they may modify strongly the light-absorption properties and hence the colour and photochemistry of the carotenoids.
Solar-terrestrial interactions
NASA Technical Reports Server (NTRS)
The effects of solar radiation on man's environment are discussed. It is solar radiation that is the basic energy source driving the circulations of the earth's atmosphere and oceans. Solar radiation is responsible for the ionization of the earth's upper atmosphere to form the ionosphere, which is important to our understanding of the magnetosphere and its interaction with the solar wind. The solar wind, which is the continuous (but not steady) flow of the sun's coronal plasma and magnetic field into interplanetary space, plays both an active and passive role in its interaction with the earth's environment.
Identifying Gene Interaction Networks
Bebek, Gurkan
In this chapter, we introduce interaction networks by describing how they are generated, where they are stored, and how they are shared. We focus on publicly available interaction networks and describe a simple way of utilizing these resources. As a case study, we used Cytoscape, an open source and easy-to-use network visualization and analysis tool to first gather and visualize a small network. We have analyzed this network's topological features and have looked at functional enrichment of the network nodes by integrating the gene ontology database. The methods described are applicable to larger networks that can be collected from various resources. PMID:22307715
Interactive holographic display
NASA Astrophysics Data System (ADS)
Son, Jung-Young; Lee, Beam-Ryeol; Kim, Jin-Woong; Chernyshov, Oleksii O.; Park, Min-Chul
A holographic display which is capable of displaying floating holographic images is introduced. The display is for user interaction with the image on the display. It consists of two parts; multiplexed holographic image generation and a spherical mirror. The time multiplexed image from 2 X 10 DMD frames appeared on PDLC screen is imaged by the spherical mirror and becomes a floating image. This image is combined spatially with two layered TV images appearing behind. Since the floating holographic image has a real spatial position and depth, it allows a user to interact with the image.
Fox, P.B.; Yatabe, M.
The Nuclear Criticality Safety Analytical Methods Resource Center announces the availability of a new interactive version of CESAR, a critical experiments storage and retrieval program available on the Nuclear Criticality Information System (NCIS) data base at Lawrence Livermore National Laboratory. The original version of CESAR did not include interactive search capabilities. The CESAR data base was developed to provide a convenient, readily accessible means of storing and retrieving code input data for the SCALE criticality safety analytical sequences and the codes comprising those sequences. The data base includes data for both cross-section preparation and criticality safety calculations.
Fox, P.B.; Yatabe, M.
In this report the Nuclear Criticality Safety Analytical Methods Resource Center describes a new interactive version of CESAR, a critical experiments storage and retrieval program available on the Nuclear Criticality Information System (NCIS) database at Lawrence Livermore National Laboratory. The original version of CESAR did not include interactive search capabilities. The CESAR database was developed to provide a convenient, readily accessible means of storing and retrieving code input data for the SCALE Criticality Safety Analytical Sequences and the codes comprising those sequences. The database includes data for both cross section preparation and criticality safety calculations. 3 refs., 1 tab.
Honesty through repeated interactions.
Rich, Patricia; Zollman, Kevin J S
In the study of signaling, it is well known that the cost of deception is an essential element for stable honest signaling in nature. In this paper, we show how costs for deception can arise endogenously from repeated interactions between individuals. Utilizing the Sir Philip Sidney game as an illustrative case, we show that repeated interactions can sustain honesty with no observable signal costs, even when deception cannot be directly observed. We provide a number of potential experimental tests for this theory which distinguish it from the available alternatives. PMID:26869213
Synchronization via Hydrodynamic Interactions
NASA Astrophysics Data System (ADS)
Kendelbacher, Franziska; Stark, Holger
An object moving in a viscous fluid creates a flow field that influences the motion of neighboring objects. We review examples from nature in the microscopic world where such hydrodynamic interactions synchronize beating or rotating filaments. Bacteria propel themselves using a bundle of rotating helical filaments called flagella which have to be synchronized in phase. Other micro-organisms are covered with a carpet of smaller filaments called cilia on their surfaces. They beat highly synchronized so that metachronal waves propagate along the cell surfaces. We explore both examples with the help of simple model systems and identify generic properties for observing synchronization by hydrodynamic interactions.
Wiringa, R.B.
Nucleon-nucleon interactions are at the heart of nuclear physics, bridging the gap between QCD and the effective interactions appropriate for the shell model. We discuss the current status of {ital NN} data sets, partial-wave analyses, and some of the issues that go into the construction of potential models. Our remarks are illustrated by reference to the Argonne {ital v}{sub 18} potential, one of a number of new potentials that fit elastic nucleon-nucleon data up to 350 MeV with a {Chi}{sup 2} per datum near 1. We also discuss the related issues of three-nucleon potentials, two-nucleon charge and current operators, and relativistic effects. We give some examples of calculations that can be made using these realistic descriptions of {ital NN} interactions. We conclude with some remarks on how our empirical knowledge of {ital NN} interactions may help constrain models at the quark level, and hence models of nucleon structure.
Interactive Technology for Education.
ERIC Educational Resources Information Center
Brooks, Robert; Perl, Barry
By using the kind of two-way television system envisioned by Buckminster Fuller, school children can learn at their own rates and select interesting topics, thereby continually reinforcing the desire to learn. Today's new interactive video systems, from multimedia encyclopedias to hypermedia combinations, allow students to explore subject matter…
Dimensions of Group Interaction
ERIC Educational Resources Information Center
Dawidowicz, Paula
The correlation between positive and negative group interactions and one or another of individuals' attitudes or characteristics--moral development, critical thinking, resilience, and self efficacy--has been examined previously. However, no systemic examination of individuals' development of patterns of these characteristics and those patterns'…
GENIE final state interactions
Dytman, Steven
Final state interactions are an important component of any neutrino-nucleus Monte Carlo program. GENIE has 2 FSI programs which serve different purposes. Each has fair-good agreement with a wide range of hadron-nucleus data. Recent improvements and planned advancements are described.
Electron interaction in matter
NASA Technical Reports Server (NTRS)
Dance, W. E.; Rainwater, W. J.; Rester, D. H.
Data on the scattering of 1-MeV electrons in aluminum for the case of non-normal incidence, electron-bremsstrahlung cross-sections in thin targets, and the production of bremstrahlung by electron interaction in thick targets, are presented both in tabular and graphic form. These results may interest physicists and radiologists.
Interactive Tabletops in Education
ERIC Educational Resources Information Center
Dillenbourg, Pierre; Evans, Michael
Interactive tabletops are gaining increased attention from CSCL researchers. This paper analyses the relation between this technology and teaching and learning processes. At a global level, one could argue that tabletops convey a socio-constructivist flavor: they support small teams that solve problems by exploring multiple solutions. The…
Interactive Multimodal Learning Environments
ERIC Educational Resources Information Center
Moreno, Roxana; Mayer, Richard
What are interactive multimodal learning environments and how should they be designed to promote students' learning? In this paper, we offer a cognitive-affective theory of learning with media from which instructional design principles are derived. Then, we review a set of experimental studies in which we found empirical support for five design…
Magnetospheres: Jupiter, Satellite Interactions
NASA Astrophysics Data System (ADS)
Neubauer, F.; Murdin, P.
Most of the satellites of Jupiter, notably the large Galilean satellites Io, Europa, Ganymede and Callisto (see JUPITER: SATELLITES), orbit deep inside the magnetosphere of Jupiter (see JUPITER: MAGNETOSPHERE) and are therefore immersed in the flow of magnetospheric plasma (made of a mixture of electrons and ions) and subjected to an interaction with the strong Jovian magnetic field. These intera...
Interactions among methanotrophs
Starostina, N.G.; Pashkova, N.I.; Gorkina, N.B.; Tsiomenko, A.B.
The character of interactions among methanotrophs was investigated. All five known general of methanotrophs were screened. Pair interactions between 45 collection cultures (in 1825 pairs) were studied. Antagonism was found to be a predominant type of interactions between cultures (in more than 90% of pairs). Few interactions (less than 2%) were positive, and the others were neutral. Methanotrophs of type I exhibited a high antagonistic activity. They inhibited the growth of nearly all cultures of both types, the degree of inhibition being maximal in the majority of cases. Among type II methanotrophs, high antagonistic activity was exhibited by less than 30% of cultures. The methanotrophs of type I were inhibited by methanotrophs of type II much more weakly than type II bacteria by type I cultures. The growth of some strains of type I was even stimulated by the cultures of type II. A possible differentiation of the roles of methanotrophs of both types in natural associations is assumed to be normally predominant, and type II methanotrophs are supposed to take up the basic functions of the association under unfavorable environmental conditions. 14 refs., 2 figs., 3 tabs.
Interactions of cosmic superstrings
Jackson, Mark G.; /Fermilab
We develop methods by which cosmic superstring interactions can be studied in detail. These include the reconnection probability and emission of radiation such as gravitons or small string loops. Loop corrections to these are discussed, as well as relationships to (p; q)-strings. These tools should allow a phenomenological study of string models in anticipation of upcoming experiments sensitive to cosmic string radiation.
Interactive Genetics Tutorial Project.
ERIC Educational Resources Information Center
Wisconsin Univ., Madison. Dept. of Curriculum and Instruction.
The Interactive Genetics Tutorial (IGT) project and the Intelligent Tutoring System for the IGT project named MENDEL supplement genetics instruction in biology courses by providing students with experience in designing, conducting, and evaluating genetics experiments. The MENDEL software is designed to: (1) simulate genetics experiments that…
ERIC Educational Resources Information Center
Deaton, Cynthia Minchew; Deaton, Benjamin E.; Leland, Katina
The authors created an interactive reflective log (IRL) to provide teachers with an opportunity to use a journal approach to record, evaluate, and communicate student understanding of science concepts. Unlike a traditional journal, the IRL incorporates prompts to encourage students to discuss their understanding of science content and science…
Standardizing Interaction Design Education
ERIC Educational Resources Information Center
Thomassen, Aukje; Ozcan, Oguzhan
The objective of this paper is to which extend the didactic format of studio-based group-work is applicable for creating a common-ground for Interaction Design Education in European Perspective. The current debate on design education shows us a landscape of different initiatives. So far difficulties have arisen in the area of accreditation and…
Electronically Enhanced Classroom Interaction.
ERIC Educational Resources Information Center
Draper, Stephen; Cargill, Julie; Cutts, Quintin
A design rationale for introducing electronic equipment (a group response system) for student interaction in lecture theaters is presented, linking the instructional design to theory. The effectiveness of the equipment for learning depends mostly on what pedagogic method is employed. Various alternative types are introduced, including: assessment;…
Connectionist Interaction Information Retrieval.
ERIC Educational Resources Information Center
Dominich, Sandor
Discussion of connectionist views for adaptive clustering in information retrieval focuses on a connectionist clustering technique and activation spreading-based information retrieval model using the interaction information retrieval method. Presents theoretical as well as simulation results as regards computational complexity and includes…
GENIE final state interactions
NASA Astrophysics Data System (ADS)
Dytman, Steven
Final state interactions are an important component of any neutrino-nucleus Monte Carlo program. GENIE has 2 FSI programs which serve different purposes. Each has fair-good agreement with a wide range of hadron-nucleus data. Recent improvements and planned advancements are described.
Interactive shape metamorphosis
NASA Technical Reports Server (NTRS)
Chen, David T.; State, Andrei; Banks, David
A technique for controlled metamorphosis between surfaces in 3-space is described. Well-understood techniques to produce shape metamorphosis between models in a 2D parametric space is applied. The user selects morphable features interactively, and the morphing process executes in real time on a high-performance graphics multicomputer.
Latent Variable Interaction Modeling.
ERIC Educational Resources Information Center
Schumacker, Randall E.
Used simulation to study two different approaches to latent variable interaction modeling with continuous observed variables: (1) a LISREL 8.30 program and (2) data analysis through PRELIS2 and SIMPLIS programs. Results show that parameter estimation was similar but standard errors were different. Discusses differences in ease of implementation.…
Quantity Estimation Of The Interactions
Gorana, Agim; Malkaj, Partizan; Muda, Valbona
In this paper we present some considerations about quantity estimations, regarding the range of interaction and the conservations laws in various types of interactions. Our estimations are done under classical and quantum point of view and have to do with the interaction's carriers, the radius, the influence range and the intensity of interactions.
Aronson, J
Of the many varieties of drug interactions, which occur when the disposition or actions of one drug are changed by another, only a few are serious or potentially fatal. A representative outline of some of these illustrates the problem. Precipitant drugs are those which produce the interaction, and object drugs are those whose effects are changed. The interactions which are usually significant are those which alter the metabolism, involve renal excretion, or change the effects of the object drug, especially when the object drug has a low therapeutic index (cardiovascular drugs, anticoagulants, drugs acting on the brain, hypoglycemic drugs, hormones, and cytotoxic drugs). Warfarin toxicity, for example, is produced by aspirin, phenylbutazone, and azapropazone. The dosage requirements of warfarin are reduced by chloramphenicol, ciprofloxacin and other quinolones, erythromycin and some of the other macrolides, metronidazole and other imidazoles, tetracyclines, amiodarone, cimetidine (but not ranitidine), and fibrates. Potassium-depleting drugs can potentiate the action of digoxin, and the elimination of digoxin can be reduced by amiodarone, propafenone, quinidine, and verapamil. Combined oral contraceptives can lose effectiveness through the interaction of carbamazepine, griseofulvin, phenytoin, or rifampicin, which increase estrogen metabolism. In addition, broad-spectrum antibiotics such as ampicillin or tetracyclines also reduce contraceptive effectiveness by altering gut absorption. Even a single drink of an alcoholic beverage may be dangerous to people taking antidepressants, antihistamines, antipsychotic drugs, benzodiazepines, or lithium. Antihistamines suffer inhibited metabolism in the liver if taken in conjunction with the antifungal imidazoles and some of the macrolide antibiotics. Cardiotoxicity of antihistamines is also enhanced by drugs with similar cardiotoxic effects. Lithium potentiation is enhanced by the new serotonin-reuptake inhibitors, and lithium
Interactive protein manipulation
We describe an interactive visualization and modeling program for the creation of protein structures ''from scratch''. The input to our program is an amino acid sequence -decoded from a gene- and a sequence of predicted secondary structure types for each amino acid-provided by external structure prediction programs. Our program can be used in the set-up phase of a protein structure prediction process; the structures created with it serve as input for a subsequent global internal energy minimization, or another method of protein structure prediction. Our program supports basic visualization methods for protein structures, interactive manipulation based on inverse kinematics, and visualization guides to aid a user in creating ''good'' initial structures.
Interactive digital signal processor
NASA Technical Reports Server (NTRS)
Mish, W. H.; Wenger, R. M.; Behannon, K. W.; Byrnes, J. B.
The Interactive Digital Signal Processor (IDSP) is examined. It consists of a set of time series analysis Operators each of which operates on an input file to produce an output file. The operators can be executed in any order that makes sense and recursively, if desired. The operators are the various algorithms used in digital time series analysis work. User written operators can be easily interfaced to the sysatem. The system can be operated both interactively and in batch mode. In IDSP a file can consist of up to n (currently n=8) simultaneous time series. IDSP currently includes over thirty standard operators that range from Fourier transform operations, design and application of digital filters, eigenvalue analysis, to operators that provide graphical output, allow batch operation, editing and display information.
Electron: Cluster interactions
Scheidemann, A.A.; Kresin, V.V.; Knight, W.D.
Beam depletion spectroscopy has been used to measure absolute total inelastic electron-sodium cluster collision cross sections in the energy range from E {approximately} 0.1 to E {approximately} 6 eV. The investigation focused on the closed shell clusters Na{sub 8}, Na{sub 20}, Na{sub 40}. The measured cross sections show an increase for the lowest collision energies where electron attachment is the primary scattering channel. The electron attachment cross section can be understood in terms of Langevin scattering, connecting this measurement with the polarizability of the cluster. For energies above the dissociation energy the measured electron-cluster cross section is energy independent, thus defining an electron-cluster interaction range. This interaction range increases with the cluster size.
Microsporidia-Host Interactions
Szumowski, Suzannah C.; Troemel, Emily R.
Microsporidia comprise one of the largest groups of obligate intracellular pathogens and can infect virtually all animals, but host response to these fungal-related microbes has been poorly understood. Several new studies of the host transcriptional response to microsporidia infection have found infection-induced regulation of genes involved in innate immunity, ubiquitylation, metabolism, and hormonal signaling. In addition, microsporidia have recently been shown to exploit host recycling endocytosis for exit from intestinal cells, and to interact with host degradation pathways. Microsporidia infection has also been shown to profoundly affect behavior in insect hosts. Altogether, these and other recent findings are providing much-needed insight into the underlying mechanisms of microsporidia interaction with host animals. PMID:25847674
Veligdan, James T.
An interactive optical panel assembly 34 includes an optical panel 10 having a plurality of ribbon optical waveguides 12 stacked together with opposite ends thereof defining panel first and second faces 16, 18. A light source 20 provides an image beam 22 to the panel first face 16 for being channeled through the waveguides 12 and emitted from the panel second face 18 in the form of a viewable light image 24a. A remote device 38 produces a response beam 40 over a discrete selection area 36 of the panel second face 18 for being channeled through at least one of the waveguides 12 toward the panel first face 16. A light sensor 42,50 is disposed across a plurality of the waveguides 12 for detecting the response beam 40 therein for providing interactive capability.
Kirtland, Karen A; Burrows, Nilka R; Geiss, Linda S
The Diabetes Interactive Atlas is a recently released Web-based collection of maps that allows users to view geographic patterns and examine trends in diabetes and its risk factors over time across the United States and within states. The atlas provides maps, tables, graphs, and motion charts that depict national, state, and county data. Large amounts of data can be viewed in various ways simultaneously. In this article, we describe the design and technical issues for developing the atlas and provide an overview of the atlas' maps and graphs. The Diabetes Interactive Atlas improves visualization of geographic patterns, highlights observation of trends, and demonstrates the concomitant geographic and temporal growth of diabetes and obesity. PMID:24503340
Volcanism-Climate Interactions
NASA Technical Reports Server (NTRS)
Walter, Louis S. (Editor); Desilva, Shanaka (Editor)
The range of disciplines in the study of volcanism-climate interactions includes paleoclimate, volcanology, petrology, tectonics, cloud physics and chemistry, and climate and radiation modeling. Questions encountered in understanding the interactions include: the source and evolution of sulfur and sulfur-gaseous species in magmas; their entrainment in volcanic plumes and injection into the stratosphere; their dissipation rates; and their radiative effects. Other issues include modeling and measuring regional and global effects of such large, dense clouds. A broad-range plan of research designed to answer these questions was defined. The plan includes observations of volcanoes, rocks, trees, and ice cores, as well as satellite and aircraft observations of erupting volcanoes and resulting lumes and clouds.
Evolution of intrafamilial interactions.
Lynch, M
A theory for the evolution of behavioral interactions among relatives is developed that allows for genetic correlations between the types of behavior that are expressed in different social contexts. Both theoretical and empirical considerations indicate that such genetic constraints will almost certainly be common in natural populations. It is shown that when genetic correlations between elements of social behavior exist, Hamilton's rule inaccurately describes the conditions for evolution by way of kin selection. The direction in which social organization evolves is a delicate function of the genetic covariance structure among behaviors expressed as an offspring, sibling, parent, etc. A change in this covariance structure caused by random genetic drift or by a change in environment for a population exhibiting genotype-environment interaction can cause the population to suddenly cross a threshold into a new selective domain. Consequently, radical changes in social organization may arise between closely related species without any major shift in selective pressures external to the population. Images PMID:3479804
Veligdan, J.T.
An interactive optical panel assembly includes an optical panel having a plurality of ribbon optical waveguides stacked together with opposite ends thereof defining panel first and second faces. A light source provides an image beam to the panel first face for being channeled through the waveguides and emitted from the panel second face in the form of a viewable light image. A remote device produces a response beam over a discrete selection area of the panel second face for being channeled through at least one of the waveguides toward the panel first face. A light sensor is disposed across a plurality of the waveguides for detecting the response beam therein for providing interactive capability. 10 figs.
Pomplun, Alan R. (Sandia National Laboratories, Livermore, CA)
Sandia's advanced computing resources provide researchers, engineers and analysts with the ability to develop and render highly detailed large-scale models and simulations. To take full advantage of these multi-million data point visualizations, display systems with comparable pixel counts are needed. The Interactive Design Center (IDC) is a second generation visualization theater designed to meet this need. The main display integrates twenty-seven projectors in a 9-wide by 3-high array with a total display resolution of more than 35 million pixels. Six individual SmartBoard displays offer interactive capabilities that include on-screen annotation and touch panel control of the facility's display systems. This report details the design, implementation and operation of this innovative facility.
Drug Interaction and Pharmacist
Ansari, JA
The topic of drug–drug interactions has received a great deal of recent attention from the regulatory, scientific, and health care communities worldwide. Nonsteroidal anti-inflammatory drugs, antibiotics and, in particular, rifampin are common precipitant drugs prescribed in primary care practice. Drugs with a narrow therapeutic range or low therapeutic index are more likely to be the objects for serious drug interactions. Object drugs in common use include warfarin, fluoroquinolones, antiepileptic drugs, oral contraceptives, cisapride, and 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors. The pharmacist, along with the prescriber has a duty to ensure that patients are aware of the risk of side effects and a suitable course of action should they occur. With their detailed knowledge of medicine, pharmacists have the ability to relate unexpected symptoms experienced by patients to possible adverse effects of their drug therapy. PMID:21042495
Interactive chemical reactivity exploration.
Haag, Moritz P; Vaucher, Alain C; Bosson, Maël; Redon, Stéphane; Reiher, Markus
Elucidating chemical reactivity in complex molecular assemblies of a few hundred atoms is, despite the remarkable progress in quantum chemistry, still a major challenge. Black-box search methods to find intermediates and transition-state structures might fail in such situations because of the high-dimensionality of the potential energy surface. Here, we propose the concept of interactive chemical reactivity exploration to effectively introduce the chemist's intuition into the search process. We employ a haptic pointer device with force feedback to allow the operator the direct manipulation of structures in three dimensions along with simultaneous perception of the quantum mechanical response upon structure modification as forces. We elaborate on the details of how such an interactive exploration should proceed and which technical difficulties need to be overcome. All reactivity-exploration concepts developed for this purpose have been implemented in the samson programming environment. PMID:25205397
Combustor diffuser interaction program
NASA Technical Reports Server (NTRS)
Srinivasan, Ram; Thorp, Daniel
Advances in gas turbine engine performance are achieved by using compressor systems with high stage loading and low part count, which result in high exit Mach numbers. The diffuser and combustor systems in such engines should be optimized to reduce system pressure loss and to maximize the engine thrust-to-weight ratio and minimize length. The state-of-the-art combustor-diffuser systems do not meet these requirements. Detailed understanding of the combustor-diffuser flow field interaction is required for designing advanced gas turbine engines. An experimental study of the combustor-diffuser interaction (CDI) is being conducted to obtain data for the evaluation and improvement of analytical models applicable to a wide variety of diffuser designs. The CDI program consists of four technical phases: Literature Search; Baseline Configuration; Parametric Configurations; and Performance Configurations. Phase 2 of the program is in progress.
Abdominal Circulatory Interactions.
Dagar, Gaurav; Taneja, Amit; Nanchal, Rahul S
The abdominal compartment is separated from the thoracic compartment by the diaphragm. Under normal circumstances, a large portion of the venous return crosses the splanchnic and nonsplanchnic abdominal regions before entering the thorax and the right side of the heart. Mechanical ventilation may affect abdominal venous return independent of its interactions at the thoracic level. Changes in pressure in the intra-abdominal compartment may have important implications for organ function within the thorax, particularly if there is a sustained rise in intra-abdominal pressure. It is important to understand the consequences of abdominal pressure changes on respiratory and circulatory physiology. This article elucidates important abdominal-respiratory-circulatory interactions and their clinical effects. PMID:27016167
Liu, Liuming
We calculate the scattering lengths of the scattering processes where one or both hadrons contain charm quarks in full lattice QCD. We use relativistic Fermilab formulation for the charm quark. For the light quark, we use domain-wall fermions in the valence sector and improved Kogut- Susskind sea quarks. In J = Psi - N and D - K channels, we observe attractive interactions. In D - D* channel, the sign of the scattering length changes, which suggests a bound state.
Structural control interaction
NASA Technical Reports Server (NTRS)
Ryan, R. S.; Mowery, D. K.; Winder, S. W.; Worley, H. E.
The basic guidance and control concepts that lead to structural control interaction and structural dynamic loads are identified. Space vehicle ascent flight load sources and the load relieving mechanism are discussed, along with the the characteristics and special problems of both present and future space vehicles including launch vehicles, orbiting vehicles, and the Space Shuttle flyback vehicle. The special dynamics and control analyses and test problems apparent at this time are summarized.
Cruz, Norman; Palma, Guillermo; Zambrano, David; Avelino, Arturo E-mail: email@example.com E-mail: firstname.lastname@example.com
We explore a cosmological model composed by a dark matter fluid interacting with a dark energy fluid. The interaction term has the non-linear λρ{sub m}{sup α}ρ{sub e}{sup β} form, where ρ{sub m} and ρ{sub e} are the energy densities of the dark matter and dark energy, respectively. The parameters α and β are in principle not constrained to take any particular values, and were estimated from observations. We perform an analytical study of the evolution equations, finding the fixed points and their stability properties in order to characterize suitable physical regions in the phase space of the dark matter and dark energy densities. The constants (λ,α,β) as well as w{sub m} and w{sub e} of the EoS of dark matter and dark energy respectively, were estimated using the cosmological observations of the type Ia supernovae and the Hubble expansion rate H(z) data sets. We find that the best estimated values for the free parameters of the model correspond to a warm dark matter interacting with a phantom dark energy component, with a well goodness-of-fit to data. However, using the Bayesian Information Criterion (BIC) we find that this model is overcame by a warm dark matter – phantom dark energy model without interaction, as well as by the ΛCDM model. We find also a large dispersion on the best estimated values of the (λ,α,β) parameters, so even if we are not able to set strong constraints on their values, given the goodness-of-fit to data of the model, we find that a large variety of theirs values are well compatible with the observational data used.
The High-Energy Elementary Particle Interactions group at UT during the last three years worked on the following directions and projects: Collider-based Particle Physics; Neutrino Physics, particularly participation in "NOνA", "Double Chooz", and "KamLAND" neutrino experiments; and Theory, including Scattering amplitudes, Quark-gluon plasma; Holographic cosmology; Holographic superconductors; Charge density waves; Striped superconductors; and Holographic FFLO states.
[Unexpected drug-interaction].
Tajima, Yutaka
The case of a male patient suffering from chronic normal pressure hydrocephalus is outlined. Antidepressant and pravastatin were administered because of the patient's abulia and hypercholesterolemia, but neuroleptic malignant syndrome-like conditions developed. All physicians should suppose the occurrence of such an "unexpected drug-interaction" in any case. The author considered that a good sense of careful discernment and rapid reference system of medical information are "essential tools" for clinical management. PMID:11925849
Neutrino Interactions with Nuclei
Leitner, T.; Buss, O.; Mosel, U.; Alvarez-Ruso, L.
We investigate neutrino-nucleus collisions at intermediate energies incorporating quasielastic scattering and the excitation of 13 resonances as elementary processes, taking into account medium effects such as Fermi motion, Pauli blocking, mean-field potentials and in-medium spectral functions. A coupled-channel treatment of final state interactions is achieved with the GiBUU transport model. Results for inclusive reactions, neutrino- and electron-induced, as well as for pion production and nucleon knockout are presented.
Interactive reservoir simulation
Regtien, J.M.M. Por, G.J.A.; Stiphout, M.T. van; Vlugt, F.F. van der
Shell`s new Modular Reservoir Simulator (MoReS) has been equipped with a comprehensive and versatile user interface called FrontEnd. Apart from providing a user-friendly environment for interactive reservoir simulation, FrontEnd serves a software platform for other dynamic simulation and reservoir-engineering applications. It offers to all supported applications a common user interface, enables the re-use of code and reduces overall maintenance and support costs associated with the embedded applications. Because of its features, FrontEnd facilitates the transfer of research results in the form of operational software to end users. When coupled with MoReS, FrontEnd can be used for pre- and post-processing and interactive simulation. The pre-processing options allow data to be inputted by means of various OSF/Motif widgets containing a spreadsheet, text editors, dialogues and graphical input. The display of the input data as well as the post-processing of all simulation results is made possible by a variety of user-defined plot of tabular (e.g. timestep summary) and array (simulation grid) data. During a simulation user-defined plots can be displayed and edited, allowing a close inspection of the results as they are being calculated. FrontEnd has been equipped with a powerful input command language, which gives the batch user as much flexibility and control over the input as the interactive user.
Asynchronous interactive control systems
NASA Technical Reports Server (NTRS)
Vuskovic, M. I.; Heer, E.
A class of interactive control systems is derived by generalizing interactive manipulator control systems. The general structural properties of such systems are discussed and an appropriate general software implementation is proposed. This is based on the fact that tasks of interactive control systems can be represented as a network of a finite set of actions which have specific operational characteristics and specific resource requirements, and which are of limited duration. This has enabled the decomposition of the overall control algorithm into a set of subalgorithms, called subcontrollers, which can operate simultaneously and asynchronously. Coordinate transformations of sensor feedback data and actuator set-points have enabled the further simplification of the subcontrollers and have reduced their conflicting resource requirements. The modules of the decomposed control system are implemented as parallel processes with disjoint memory space communicating only by I/O. The synchronization mechanisms for dynamic resource allocation among subcontrollers and other synchronization mechanisms are also discussed in this paper. Such a software organization is suitable for the general form of multiprocessing using computer networks with distributed storage.
Transactional interactive multimedia banner
NASA Astrophysics Data System (ADS)
Shae, Zon-Yin; Wang, Xiping; von Kaenel, Juerg
Advertising in TV broadcasting has shown that multimedia is a very effective means to present merchandise and attract shoppers. This has been applied to the Web by including animated multimedia banner ads on web pages. However, the issues of coupling interactive browsing, shopping, and secure transactions e.g. from inside a multimedia banner, have only recently started to being explored. Currently there is an explosively growing amount of back-end services available (e.g., business to business commerce (B2B), business to consumer (B2C) commerce, and infomercial services) in the Internet. These services are mostly accessible through static HTML web pages at a few specific web portals. In this paper, we will investigate the feasibility of using interactive multimedia banners as pervasive access point for the B2C, B2B, and infomercial services. We present a system architecture that involves a layer of middleware agents functioning as the bridge between the interactive multimedia banners and back-end services.
Interacting Multiview Tracker.
Yoon, Ju Hong; Yang, Ming-Hsuan; Yoon, Kuk-Jin
A robust algorithm is proposed for tracking a target object in dynamic conditions including motion blurs, illumination changes, pose variations, and occlusions. To cope with these challenging factors, multiple trackers based on different feature representations are integrated within a probabilistic framework. Each view of the proposed multiview (multi-channel) feature learning algorithm is concerned with one particular feature representation of a target object from which a tracker is developed with different levels of reliability. With the multiple trackers, the proposed algorithm exploits tracker interaction and selection for robust tracking performance. In the tracker interaction, a transition probability matrix is used to estimate dependencies between trackers. Multiple trackers communicate with each other by sharing information of sample distributions. The tracker selection process determines the most reliable tracker with the highest probability. To account for object appearance changes, the transition probability matrix and tracker probability are updated in a recursive Bayesian framework by reflecting the tracker reliability measured by a robust tracker likelihood function that learns to account for both transient and stable appearance changes. Experimental results on benchmark datasets demonstrate that the proposed interacting multiview algorithm performs robustly and favorably against state-of-the-art methods in terms of several quantitative metrics. PMID:26336117
Interactive Learning and "Clickers"
NASA Astrophysics Data System (ADS)
Rudolph, Alexander
A growing body of evidence demonstrates that student understanding and retention of key concepts in science can be dramatically improved by using "Interactive Learning" techniques. Interactive learning is a way to get students more actively involved in their own learning than by simple lecture alone. I will focus on one type of interactive learning activity, known as "Think-Pair-Share". After a brief (10-20 minute) lecture on a topic, students are asked a conceptually challenging multiple-choice question. After they answer, if there is sufficient disagreement, the students discuss the question in small groups after which they answer the same question again. Frequently, the percentage of correct answers goes up, indicating that the active role of speaking and listening, together with peer instruction, has helped students better grasp the concept being tested. If disagreement persists, or if students continue to have questions, a short, class-wide discussion can be held. Clickers provide an excellent means to collect students' answers to "Think-Pair-Share" questions in real time. Although clickers are not essential, they do provide some advantages over alternatives such as flash cards: answers are completely anonymous (though you as instructor can record individual responses); you can display a histogram of results immediately, either before or after group discussion, providing immediate feedback; by recording the results, you can give students credit for their participation in class. In this talk, I will model "Think-Pair-Share" with the audience using clickers, show results from my classes before and after group discussions, share results of a student survey on "Think-Pair-Share" and clickers, describe other uses of clickers (e.g., taking attendance, surveys, test administration) and highlight some of the pros and cons of clickers v. flashcards.
Drugging Membrane Protein Interactions.
Yin, Hang; Flynn, Aaron D
The majority of therapeutics target membrane proteins, accessible on the surface of cells, to alter cellular signaling. Cells use membrane proteins to transduce signals into cells, transport ions and molecules, bind cells to a surface or substrate, and catalyze reactions. Newly devised technologies allow us to drug conventionally "undruggable" regions of membrane proteins, enabling modulation of protein-protein, protein-lipid, and protein-nucleic acid interactions. In this review, we survey the state of the art of high-throughput screening and rational design in drug discovery, and we evaluate the advances in biological understanding and technological capacity that will drive pharmacotherapy forward against unorthodox membrane protein targets. PMID:26863923
NASA Astrophysics Data System (ADS)
Purser, K.
Design layouts have traditionally been done on a drafting board by drawing a two-dimensional representation with section cuts and side views to describe the exact three-dimensional model. With the advent of computer graphics, a three-dimensional model can be created directly. The computer stores the exact three-dimensional model, which can be examined from any angle and at any scale. A brief overview of interactive computer graphics, how models are made and some of the benefits/limitations are described.
Scattering with absorptive interaction
NASA Astrophysics Data System (ADS)
Cassing, W.; Stingl, M.; Weiguny, A.
The S matrix for a wide class of complex and nonlocal potentials is studied, with special attention given to the motion of singularities in the complex k plane as a function of the imaginary coupling strength. Modifications of Levinson's theorem are obtained and discussed. Analytic approximations to the S matrix in the vicinity of narrow resonances are exhibited and compared to numerical results of resonating-group calculations. The problem of defining resonances in the case of complex interactions is discussed, making contact with the usual analysis of scattering in terms of Argand diagrams. NUCLEAR REACTIONS Scattering theory, S matrix for absorptive potentials.
Bunyavirus-Vector Interactions
Horne, Kate McElroy; Vanlandingham, Dana L.
The Bunyaviridae family is comprised of more than 350 viruses, of which many within the Hantavirus, Orthobunyavirus, Nairovirus, Tospovirus, and Phlebovirus genera are significant human or agricultural pathogens. The viruses within the Orthobunyavirus, Nairovirus, and Phlebovirus genera are transmitted by hematophagous arthropods, such as mosquitoes, midges, flies, and ticks, and their associated arthropods not only serve as vectors but also as virus reservoirs in many cases. This review presents an overview of several important emerging or re-emerging bunyaviruses and describes what is known about bunyavirus-vector interactions based on epidemiological, ultrastructural, and genetic studies of members of this virus family. PMID:25402172
Interacting with augmented holograms
NASA Astrophysics Data System (ADS)
Bimber, Oliver; Zeidler, Thomas; Grundhoefer, Anselm; Wetzstein, Gordon; Moehring, Mathias; Knoedel, Sebastian; Hahne, Uwe
Holography and computer graphics are being used as tools to solve individual research, engineering, and presentation problems within several domains. Up until today, however, these tools have been applied separately. Our intention is to combine both technologies to create a powerful tool for science, industry and education. We are currently investigating the possibility of integrating computer generated graphics and holograms. This paper gives an overview over our latest results. It presents several applications of interaction techniques to graphically enhanced holograms and gives a first glance on a novel method that reconstructs depth from optical holograms.
NASA Astrophysics Data System (ADS)
Bhagwani, Akhilesh; Sengar, Chitransh; Talwaniper, Jyotsna; Sharma, Shaan
The paper basically deals with the study of HCI (Human computer interaction) or BCI(Brain-Computer-Interfaces) Technology that can be used for capturing brain signals and translating them into commands that allow humans to control (just by thinking) devices such as computers, robots, rehabilitation technology and virtual reality environments. The HCI is based as a direct communication pathway between the brain and an external device. BCIs are often aimed at assisting, augmenting, or repairing human cognitive or sensory-motor functions.The paper also deals with many advantages of BCI Technology along with some of its applications and some major drawbacks.
CASSIS: Interactive spectrum analyzer
NASA Astrophysics Data System (ADS)
Cassis Team At Cesr/Irap
CASSIS (Centre d'Analyse Scientifique de Spectres Infrarouges et Submillimetriques), written in Java, is suited for broad-band spectral surveys to speed up the scientific analysis of high spectral resolution observations. It uses a local spectroscopic database made of the two molecular spectroscopic databases JPL and CDMS, as well as the atomic spectroscopic database NIST. Its tools include a LTE model and the RADEX model connected to the LAMDA molecular collisional database. CASSIS can build a line list fitting the various transitions of a given species and to directly produce rotational diagrams from these lists. CASSIS is fully integrated into HIPE, the Herschel Interactive Processing Environment, as a plug-in.
Detection of molecular interactions
Groves, John T.; Baksh, Michael M.; Jaros, Michal
A method and assay are described for measuring the interaction between a ligand and an analyte. The assay can include a suspension of colloidal particles that are associated with a ligand of interest. The colloidal particles are maintained in the suspension at or near a phase transition state from a condensed phase to a dispersed phase. An analyte to be tested is then added to the suspension. If the analyte binds to the ligand, a phase change occurs to indicate that the binding was successful.
Flavivirus-mosquito interactions.
Huang, Yan-Jang S; Higgs, Stephen; Horne, Kate McElroy; Vanlandingham, Dana L
The Flavivirus genus is in the family Flaviviridae and is comprised of more than 70 viruses. These viruses have a broad geographic range, circulating on every continent except Antarctica. Mosquito-borne flaviviruses, such as yellow fever virus, dengue virus serotypes 1-4, Japanese encephalitis virus, and West Nile virus are responsible for significant human morbidity and mortality in affected regions. This review focuses on what is known about flavivirus-mosquito interactions and presents key data collected from the field and laboratory-based molecular and ultrastructural evaluations. PMID:25421894
Cellulose synthase interacting protein
Somerville, Chris
Cellulose is the most abundant biopolymer on earth. The great abundance of cellulose places it at the forefront as a primary source of biomass for renewable biofuels. However, the knowledge of how plant cells make cellulose remains very rudimentary. Cellulose microfibrils are synthesized at the plasma membrane by hexameric protein complexes, also known as cellulose synthase complexes. The only known components of cellulose synthase complexes are cellulose synthase (CESA) proteins until the recent identification of a novel component. CSI1, which encodes CESA interacting protein 1 (CSI1) in Arabidopsis. CSI1, as the first non-CESA proteins associated with cellulose synthase complexes, opens up many opportunities. PMID:21150290
NASA Technical Reports Server (NTRS)
Session TA3 includes short reports covering: (1) Vestibulo-Oculomotor Interaction in Long-Term Microgravity; (2) Effects of Weightlessness on the Spatial Orientation of Visually Induced Eye Movements; (3) Adaptive Modification of the Three-Dimensional Vestibulo-Ocular Reflex during Prolonged Microgravity; (4) The Dynamic Change of Brain Potential Related to Selective Attention to Visual Signals from Left and Right Visual Fields; (5) Locomotor Errors Caused by Vestibular Suppression; and (6) A Novel, Image-Based Technique for Three-Dimensional Eye Measurement.
Interactive Classification Technology
NASA Technical Reports Server (NTRS)
deBessonet, Cary
The investigators upgraded a knowledge representation language called SL (Symbolic Language) and an automated reasoning system called SMS (Symbolic Manipulation System) to enable the more effective use of the technologies in automated reasoning and interactive classification systems. The overall goals of the project were: 1) the enhancement of the representation language SL to accommodate a wider range of meaning; 2) the development of a default inference scheme to operate over SL notation as it is encoded; and 3) the development of an interpreter for SL that would handle representations of some basic cognitive acts and perspectives.
Synergistic interactions and environment
Myers, N. )
This brief article describes synergistic interactions that would have a destructive impact on the environment: the role of chlorofluorocarbons linking the phenomena of ozone-layer depletion and the greenhouse effect; stresses on tropical forests (over-logging, agricultural settlement, and excess UV-B radiation due to ozone-layer depletion) that increase the susceptibility of the tract to injury from acid rain; increase in vulnerability to UV-B as a result of acid rain. Recognizing possible synergisms in advance may allow scientists to anticipate and even prevent some of the adverse repercussions.
Flavivirus-Mosquito Interactions
Huang, Yan-Jang S.; Higgs, Stephen; Horne, Kate McElroy; Vanlandingham, Dana L.
The Flavivirus genus is in the family Flaviviridae and is comprised of more than 70 viruses. These viruses have a broad geographic range, circulating on every continent except Antarctica. Mosquito-borne flaviviruses, such as yellow fever virus, dengue virus serotypes 1–4, Japanese encephalitis virus, and West Nile virus are responsible for significant human morbidity and mortality in affected regions. This review focuses on what is known about flavivirus-mosquito interactions and presents key data collected from the field and laboratory-based molecular and ultrastructural evaluations. PMID:25421894
Anomalous gauge boson interactions
Aihara, H.; Barklow, T.; Baur, U. |
We discuss the direct measurement of the trilinear vector boson couplings in present and future collider experiments. The major goals of such experiments will be the confirmation of the Standard Model (SM) predictions and the search for signals of new physics. We review our current theoretical understanding of anomalous trilinear gauge-boson self interactions. If the energy scale of the new physics is {approximately} 1 TeV, these low energy anomalous couplings are expected to be no larger than {Omicron}(10{sup {minus}2}). Constraints from high precision measurements at LEP and low energy charged and neutral current processes are critically reviewed.
Dynamical interactions of galaxy pairs
NASA Technical Reports Server (NTRS)
Athanassoula, E.
Here the author briefly reviews the dynamics of sinking satellites and the effect of companions on elliptical galaxies. The author then discusses recent work on interacting disk systems, and finally focuses on a favorite interacting pair, NGC 5194/5195.
Suppressive drug interactions between antifungals.
de Vos, Marjon G J; Bollenbach, Tobias
In this issue of Chemistry & Biology, Cokol and colleagues report a systematic study of drug interactions between antifungal compounds. Suppressive drug interactions occur more frequently than previously realized and come in different flavors with interesting implications. PMID:24766845
New particles and interactions
Gilman, F.J.; Grannis, P.D.
The Working Group on New Particles and Interactions met as a whole at the beginning and at the end of the Workshop. However, much of what was accomplished was done in five subgroups. These were devoted to: (1) new quarks and leptons; (2) technicolor; (3) supersymmetry; (4) rare decays and CP; and (5) substructure of quarks and leptons. Other aspects of new particles, e.g., Higgs, W', Z', fell to the Electroweak Working Group to consider. The central question of this Workshop of comparing anti pp (with L = 10/sup 32//cm/sup 2/-sec) with pp (with L = 10/sup 33//cm/sup 2/-sec) colliders carried through to all these subgroups. In addition there were several other aspects of hadron colliders which were considered: what does an increase in ..sqrt..s gain in cross section and resultant sensitivity to new physics versus an increase in luminosity; will polarized beams or the use of asymmetries be essential in finding new interactions; where and at what level do rate limitations due to triggering or detection systems play a role; and how and where will the detection of particles with short, but detectable, lifetimes be important. 25 references.
Titan's Variable Plasma Interaction
NASA Astrophysics Data System (ADS)
Ledvina, S. A.; Brecht, S. H.
Cassini observations have found that the plasma and magnetic field conditions upstream of Titan are far more complex than they were thought to be after the Voyager encounter. Rymer et al., (2009) used the Cassini Plasma Spectrometer (CAPS) electron observations to classify the plasma conditions along Titan's orbit into 5 types (Plasma Sheet, Lobe, Mixed, Magnetosheath and Misc.). Nemeth et al., (2011) found that the CAPS ion observations could also be separated into the same plasma regions as defined by Rymer et al. Additionally the T-96 encounter found Titan in the solar wind adding a sixth classification. Understanding the effects of the variable upstream plasma conditions on Titan's plasma interaction and the evolution of Titan's ionosphere/atmosphere is one of the main objectives of the Cassini mission. To compliment the mission we perform hybrid simulations of Titan's plasma interaction to examine the effects of the incident plasma distribution function and the flow velocity. We closely examine the results on Titan's induced magnetosphere and the resulting pickup ion properties.
Cotton and Protein Interactions
Goheen, Steven C.; Edwards, J. V.; Rayburn, Alfred R.; Gaither, Kari A.; Castro, Nathan J.
The adsorbent properties of important wound fluid proteins and cotton cellulose are reviewed. This review focuses on the adsorption of albumin to cotton-based wound dressings and some chemically modified derivatives targeted for chronic wounds. Adsorption of elastase in the presence of albumin was examined as a model to understand the interactive properties of these wound fluid components with cotton fibers. In the chronic non-healing wound, elastase appears to be over-expressed, and it digests tissue and growth factors, interfering with the normal healing process. Albumin is the most prevalent protein in wound fluid, and in highly to moderately exudative wounds, it may bind significantly to the fibers of wound dressings. Thus, the relative binding properties of both elastase and albumin to wound dressing fibers are of interest in the design of more effective wound dressings. The present work examines the binding of albumin to two different derivatives of cotton, and quantifies the elastase binding to the same derivatives following exposure of albumin to the fiber surface. An HPLC adsorption technique was employed coupled with a colorimetric enzyme assay to quantify the relative binding properties of albumin and elastase to cotton. The results of wound protein binding are discussed in relation to the porosity and surface chemistry interactions of cotton and wound proteins. Studies are directed to understanding the implications of protein adsorption phenomena in terms of fiber-protein models that have implications for rationally designing dressings for chronic wounds.
JSPAM: Interacting galaxies modeller
NASA Astrophysics Data System (ADS)
Wallin, John F.; Holincheck, Anthony; Harvey, Allen
JSPAM models galaxy collisions using a restricted n-body approach to speed up computation. Instead of using a softened point-mass potential, the software supports a modified version of the three component potential created by Hernquist (1994, ApJS 86, 389). Although spherically symmetric gravitationally potentials and a Gaussian model for the bulge are used to increase computational efficiency, the potential mimics that of a fully consistent n-body model of a galaxy. Dynamical friction has been implemented in the code to improve the accuracy of close approaches between galaxies. Simulations using this code using thousands of particles over the typical interaction times of a galaxy interaction take a few seconds on modern desktop workstations, making it ideal for rapidly prototyping the dynamics of colliding galaxies. Extensive testing of the code has shown that it produces nearly identical tidal features to those from hierarchical tree codes such as Gadget but using a fraction of the computational resources. This code was used in the Galaxy Zoo: Mergers project and is very well suited for automated fitting of galaxy mergers with automated pattern fitting approaches such as genetic algorithms. Java and Fortran versions of the code are available.
NASA Technical Reports Server (NTRS)
Kenwright, David
Aerospace data analysis tools that significantly reduce the time and effort needed to analyze large-scale computational fluid dynamics simulations have emerged this year. The current approach for most postprocessing and visualization work is to explore the 3D flow simulations with one of a dozen or so interactive tools. While effective for analyzing small data sets, this approach becomes extremely time consuming when working with data sets larger than one gigabyte. An active area of research this year has been the development of data mining tools that automatically search through gigabyte data sets and extract the salient features with little or no human intervention. With these so-called feature extraction tools, engineers are spared the tedious task of manually exploring huge amounts of data to find the important flow phenomena. The software tools identify features such as vortex cores, shocks, separation and attachment lines, recirculation bubbles, and boundary layers. Some of these features can be extracted in a few seconds; others take minutes to hours on extremely large data sets. The analysis can be performed off-line in a batch process, either during or following the supercomputer simulations. These computations have to be performed only once, because the feature extraction programs search the entire data set and find every occurrence of the phenomena being sought. Because the important questions about the data are being answered automatically, interactivity is less critical than it is with traditional approaches.
NASA Technical Reports Server (NTRS)
Buckley, D. H.
Metal direlectric surface interactions and dielectric films on metal substrates were investigated. Since interfacial interaction depends so heavily on the nature of the surfaces, analytical surface tools such as Auger emission spectroscopy, X-ray photoelectron spectroscopy and field ion microscopy were used to assist in surface and interfacial characterization. The results indicate that with metals contacting certain glasses in the clean state interfacial, bonding produces fractures in the glasses while when a film such as water is present, fractures occur in the metal near the interface. Friction forces were used to measure the interfacial bond strengths. Studies with metals contacting polymers using field ion microscopy revealed that strong bonding forces could develop being between a metal and polymer surface with polymer transferring to the metal surface in various ways depending upon the forces applied to the surface in contact. With the deposition of refractory carbides, silicides and borides onto metal and alloy substrates the presence of oxides at the interface or active gases in the deposition plasma were shown to alter interfacial properties and chemistry. Auger ion depth profile analysis indicated the chemical composition at the interface and this could be related to the mechanical, friction, and wear behavior of the coating.
Interactive Terascale Particle Visualization
NASA Technical Reports Server (NTRS)
Ellsworth, David; Green, Bryan; Moran, Patrick
This paper describes the methods used to produce an interactive visualization of a 2 TB computational fluid dynamics (CFD) data set using particle tracing (streaklines). We use the method introduced by Bruckschen et al. [2001] that pre-computes a large number of particles, stores them on disk using a space-filling curve ordering that minimizes seeks, and then retrieves and displays the particles according to the user's command. We describe how the particle computation can be performed using a PC cluster, how the algorithm can be adapted to work with a multi-block curvilinear mesh, and how the out-of-core visualization can be scaled to 296 billion particles while still achieving interactive performance on PG hardware. Compared to the earlier work, our data set size and total number of particles are an order of magnitude larger. We also describe a new compression technique that allows the lossless compression of the particles by 41% and speeds the particle retrieval by about 30%.
Strong-interaction nonuniversality
Volkas, R. R.; Foot, R.; He, X.; Joshi, G. C.
The universal QCD color theory is extended to an SU(3)/sub 1//direct product/SU(3)/sub 2//direct product/SU(3)/sub 3/ gauge theory, where quarks of the /ital i/th generation transform as triplets under SU(3)/sub /ital i// and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements.
XEphem: Interactive Astronomical Ephemeris
NASA Astrophysics Data System (ADS)
Downey, Elwood Charles
XEphem is a scientific-grade interactive astronomical ephemeris package for UNIX-like systems. Written in C, X11 and Motif, it is easily ported to systems. Among other things, XEphem: computes heliocentric, geocentric and topocentric information for all objects; has built-in support for all planets; the moons of Mars, Jupiter, Saturn, Uranus and Earth; central meridian longitude of Mars and Jupiter; Saturn's rings; and Jupiter's Great Red Spot; allows user-defined objects including stars, deepsky objects, asteroids, comets and Earth satellites; provides special efficient handling of large catalogs including Tycho, Hipparcos, GSC; displays data in configurable tabular formats in conjunction with several interactive graphical views; displays a night-at-a-glance 24 hour graphic showing when any selected objects are up; displays 3-D stereo Solar System views that are particularly well suited for visualizing comet trajectories; quickly finds all close pairs of objects in the sky; and sorts and prints all catalogs with very flexible criteria for creating custom observing lists. Its capabilities are listed more fully in the user manual introduction.
Microbiome and immunological interactions.
Kelly, Denise; Mulder, Imke E
The healthy human gut supports a complex and diverse microbiota, dominated by bacterial phylotypes belonging to Bacteroidetes and Firmicutes. In the inflamed gut, overall diversity decreases, coincident with a greater representation of Proteobacteria. There is growing evidence supporting an important role for human gut bacteria in mucosal immunity; interactions at the level of both intestinal and colonic epithelial cells, dendritic cells, and T and B immune cells have been documented. These interactions influence gut barrier and defense mechanisms that include antimicrobial peptide and secretory IgA synthesis. The functional effects of commensal bacteria on T helper cell differentiation have led to the emerging concept that microbiota composition determines T effector- and T regulatory-cell balance, immune responsiveness, and homeostasis. The importance of this biology in relation to immune homeostasis, inflammatory bowel disease, and the rising incidence of autoimmune diseases will be discussed. The detailed description of the human gut microbiota, integrated with evidence-based mechanisms of immune modulation, provides an exciting platform for the identification of next-generation probiotics and related pharmaceutical products. PMID:22861803
The Configuration Interaction Method
NASA Astrophysics Data System (ADS)
Sherrill, C. David; Schaefer, Henry F., III
Highly correlated configuration interaction (CI) wavefunctions going beyond the simple singles and doubles (CISD) model space can provide very reliable potential energy surfaces, describe electronic excited states, and yield benchmark energies and molecular properties for use in calibrating more approximate methods. Unfortunately, such wavefunctions are also notoriously difficult to evaluate due to their extreme computational demands. The dimension of a full CI procedure, which represents the exact solution of the electronic Schrödinger equation for a fixed one-particle basis set, grows factorially with the number of electrons and basis functions. For very large configuration spaces, the number of CI coupling coefficients becomes prohibitively large to store on disk; these coefficients must be evaluated as needed in a so-called direct CI procedure. Work done by several groups since 1980 has focused on using Slater determinants rather than spin (S2) eigenfunctions because coupling coefficients are easier to compute with the former. We review the fundamentals of the configuration interaction method and discuss various determinant-based CI algorithms. Additionally, we consider some applications of highly correlated CI methods.
Charged Dust Aggregate Interactions
NASA Astrophysics Data System (ADS)
Matthews, Lorin; Hyde, Truell
A proper understanding of the behavior of dust particle aggregates immersed in a complex plasma first requires a knowledge of the basic properties of the system. Among the most important of these are the net electrostatic charge and higher multipole moments on the dust aggregate as well as the manner in which the aggregate interacts with the local electrostatic fields. The formation of elongated, fractal-like aggregates levitating in the sheath electric field of a weakly ionized RF generated plasma discharge has recently been observed experimentally. The resulting data has shown that as aggregates approach one another, they can both accelerate and rotate. At equilibrium, aggregates are observed to levitate with regular spacing, rotating about their long axis aligned parallel to the sheath electric field. Since gas drag tends to slow any such rotation, energy must be constantly fed into the system in order to sustain it. A numerical model designed to analyze this motion provides both the electrostatic charge and higher multipole moments of the aggregate while including the forces due to thermophoresis, neutral gas drag, and the ion wakefield. This model will be used to investigate the ambient conditions leading to the observed interactions. This research is funded by NSF Grant 1414523.
Online Learners' Preferences for Interaction.
ERIC Educational Resources Information Center
Northrup, Pamela T.
Describes a study that investigated types of interaction that graduate students perceived to be important for elearning (electronic learning). Discusses content interaction, conversation and collaboration, interpersonal and metacognitive skills, and need for support; explains the Online Learning Interaction Inventory; and reports that flexibility…
Expanding the Interaction Equivalency Theorem
ERIC Educational Resources Information Center
Rodriguez, Brenda Cecilia Padilla; Armellini, Alejandro
Although interaction is recognised as a key element for learning, its incorporation in online courses can be challenging. The interaction equivalency theorem provides guidelines: Meaningful learning can be supported as long as one of three types of interactions (learner-content, learner-teacher and learner-learner) is present at a high level. This…
Species interactions and plant polyploidy.
Segraves, Kari A; Anneberg, Thomas J
Polyploidy is a common mode of speciation that can have far-reaching consequences for plant ecology and evolution. Because polyploidy can induce an array of phenotypic changes, there can be cascading effects on interactions with other species. These interactions, in turn, can have reciprocal effects on polyploid plants, potentially impacting their establishment and persistence. Although there is a wealth of information on the genetic and phenotypic effects of polyploidy, the study of species interactions in polyploid plants remains a comparatively young field. Here we reviewed the available evidence for how polyploidy may impact many types of species interactions that range from mutualism to antagonism. Specifically, we focused on three main questions: (1) Does polyploidy directly cause the formation of novel interactions not experienced by diploids, or does it create an opportunity for natural selection to then form novel interactions? (2) Does polyploidy cause consistent, predictable changes in species interactions vs. the evolution of idiosyncratic differences? (3) Does polyploidy lead to greater evolvability in species interactions? From the scarce evidence available, we found that novel interactions are rare but that polyploidy can induce changes in pollinator, herbivore, and pathogen interactions. Although further tests are needed, it is likely that selection following whole-genome duplication is important in all types of species interaction and that there are circumstances in which polyploidy can enhance the evolvability of interactions with other species. PMID:27370313
Ridge Regression for Interactive Models.
ERIC Educational Resources Information Center
Tate, Richard L.
An exploratory study of the value of ridge regression for interactive models is reported. Assuming that the linear terms in a simple interactive model are centered to eliminate non-essential multicollinearity, a variety of common models, representing both ordinal and disordinal interactions, are shown to have "orientations" that are favorable to…
NASA Technical Reports Server (NTRS)
Sandor, Aniko; Cross, E. Vincent, II; Chang, Mai Lee
Human-robot interaction (HRI) is a discipline investigating the factors affecting the interactions between humans and robots. It is important to evaluate how the design of interfaces affect the human's ability to perform tasks effectively and efficiently when working with a robot. By understanding the effects of interface design on human performance, workload, and situation awareness, interfaces can be developed to appropriately support the human in performing tasks with minimal errors and with appropriate interaction time and effort. Thus, the results of research on human-robot interfaces have direct implications for the design of robotic systems. For efficient and effective remote navigation of a rover, a human operator needs to be aware of the robot's environment. However, during teleoperation, operators may get information about the environment only through a robot's front-mounted camera causing a keyhole effect. The keyhole effect reduces situation awareness which may manifest in navigation issues such as higher number of collisions, missing critical aspects of the environment, or reduced speed. One way to compensate for the keyhole effect and the ambiguities operators experience when they teleoperate a robot is adding multiple cameras and including the robot chassis in the camera view. Augmented reality, such as overlays, can also enhance the way a person sees objects in the environment or in camera views by making them more visible. Scenes can be augmented with integrated telemetry, procedures, or map information. Furthermore, the addition of an exocentric (i.e., third-person) field of view from a camera placed in the robot's environment may provide operators with the additional information needed to gain spatial awareness of the robot. Two research studies investigated possible mitigation approaches to address the keyhole effect: 1) combining the inclusion of the robot chassis in the camera view with augmented reality overlays, and 2) modifying the camera
NASA Technical Reports Server (NTRS)
Preheim, L. E.
The Interactive DIF Generator (IDG) utility is a tool used to generate and manipulate Directory Interchange Format files (DIF). Its purpose as a specialized text editor is to create and update DIF files which can be sent to NASA's Master Directory, also referred to as the International Global Change Directory at Goddard. Many government and university data systems use the Master Directory to advertise the availability of research data. The IDG interface consists of a set of four windows: (1) the IDG main window; (2) a text editing window; (3) a text formatting and validation window; and (4) a file viewing window. The IDG main window starts up the other windows and contains a list of valid keywords. The keywords are loaded from a user-designated file and selected keywords can be copied into any active editing window. Once activated, the editing window designates the file to be edited. Upon switching from the editing window to the formatting and validation window, the user has options for making simple changes to one or more files such as inserting tabs, aligning fields, and indenting groups. The viewing window is a scrollable read-only window that allows fast viewing of any text file. IDG is an interactive tool and requires a mouse or a trackball to operate. IDG uses the X Window System to build and manage its interactive forms, and also uses the Motif widget set and runs under Sun UNIX. IDG is written in C-language for Sun computers running SunOS. This package requires the X Window System, Version 11 Revision 4, with OSF/Motif 1.1. IDG requires 1.8Mb of hard disk space. The standard distribution medium for IDG is a .25 inch streaming magnetic tape cartridge in UNIX tar format. It is also available on a 3.5 inch diskette in UNIX tar format. The program was developed in 1991 and is a copyrighted work with all copyright vested in NASA. SunOS is a trademark of Sun Microsystems, Inc. X Window System is a trademark of Massachusetts Institute of Technology. OSF/Motif is a
Quadratic spatial soliton interactions
NASA Astrophysics Data System (ADS)
Jankovic, Ladislav
Quadratic spatial soliton interactions were investigated in this Dissertation. The first part deals with characterizing the principal features of multi-soliton generation and soliton self-reflection. The second deals with two beam processes leading to soliton interactions and collisions. These subjects were investigated both theoretically and experimentally. The experiments were performed by using potassium niobate (KNBO 3) and periodically poled potassium titanyl phosphate (KTP) crystals. These particular crystals were desirable for these experiments because of their large nonlinear coefficients and, more importantly, because the experiments could be performed under non-critical-phase-matching (NCPM) conditions. The single soliton generation measurements, performed on KNBO3 by launching the fundamental component only, showed a broad angular acceptance bandwidth which was important for the soliton collisions performed later. Furthermore, at high input intensities multi-soliton generation was observed for the first time. The influence on the multi-soliton patterns generated of the input intensity and beam symmetry was investigated. The combined experimental and theoretical efforts indicated that spatial and temporal noise on the input laser beam induced multi-soliton patterns. Another research direction pursued was intensity dependent soliton routing by using of a specially engineered quadratically nonlinear interface within a periodically poled KTP sample. This was the first time demonstration of the self-reflection phenomenon in a system with a quadratic nonlinearity. The feature investigated is believed to have a great potential for soliton routing and manipulation by engineered structures. A detailed investigation was conducted on two soliton interaction and collision processes. Birth of an additional soliton resulting from a two soliton collision was observed and characterized for the special case of a non-planar geometry. A small amount of spiraling, up to 30
Transient complex peroxisomal interactions
Bonekamp, Nina A.; Schrader, Michael
Mitochondria and peroxisomes are ubiquitous subcellular organelles that fulfill essential metabolic functions, rendering them indispensable for human development and health. Both are highly dynamic organelles that can undergo remarkable changes in morphology and number to accomplish cellular needs. While mitochondrial dynamics are also regulated by frequent fusion events, the fusion of mature peroxisomes in mammalian cells remained a matter of debate. In our recent study, we clarified systematically that there is no complete fusion of mature peroxisomes analogous to mitochondria. Moreover, in contrast to key division components such as DLP1, Fis1 or Mff, mitochondrial fusion proteins were not localized to peroxisomes. However, we discovered and characterized novel transient, complex interactions between individual peroxisomes which may contribute to the homogenization of the often heterogeneous peroxisomal compartment, e.g., by distribution of metabolites, signals or other "molecular information" via interperoxisomal contact sites. PMID:23336019
NASA Astrophysics Data System (ADS)
Shugan, I.; Hwung, Hwung-Hweng; Yang, Ray-Yeng
The problem of wave interaction with current is still a big challenge in physical oceanography. In spite of numerous numbers of papers devoting to the analysis of the phenomenon some very strong effects are still waiting for its clear description. One of the problems here is the Benjamin-Feir instability in the presence of variable current. Modulation instability is one of the most ubiquitous types of instabilities in nature. In modern nonlinear physics, it is considered as a basic process that classifies the qualitative behavior of modulated waves (``envelope waves'') and may initialize the formation of stable entities such as envelope solitons. We theoretically describe the explosion instability of waves on the adverse blocking current and corresponding frequency downshifting. Waves can be blocked only partly and overpass the opposite current barrier at the lower side band resonance frequency. Theoretical results are compared with available experiments.
Causal electromagnetic interaction equations
Zinoviev, Yury M.
For the electromagnetic interaction of two particles the relativistic causal quantum mechanics equations are proposed. These equations are solved for the case when the second particle moves freely. The initial wave functions are supposed to be smooth and rapidly decreasing at the infinity. This condition is important for the convergence of the integrals similar to the integrals of quantum electrodynamics. We also consider the singular initial wave functions in the particular case when the second particle mass is equal to zero. The discrete energy spectrum of the first particle wave function is defined by the initial wave function of the free-moving second particle. Choosing the initial wave functions of the free-moving second particle it is possible to obtain a practically arbitrary discrete energy spectrum.
Interactive molecular dynamics
NASA Astrophysics Data System (ADS)
Schroeder, Daniel V.
Interlayer interactions in graphites
Chen, Xiaobin; Tian, Fuyang; Persson, Clas; Duan, Wenhui; Chen, Nan-xian
Based on ab initio calculations of both the ABC- and AB-stacked graphites, interlayer potentials (i.e., graphene-graphene interaction) are obtained as a function of the interlayer spacing using a modified Möbius inversion method, and are used to calculate basic physical properties of graphite. Excellent consistency is observed between the calculated and experimental phonon dispersions of AB-stacked graphite, showing the validity of the interlayer potentials. More importantly, layer-related properties for nonideal structures (e.g., the exfoliation energy, cleave energy, stacking fault energy, surface energy, etc.) can be easily predicted from the interlayer potentials, which promise to be extremely efficient and helpful in studying van der Waals structures. PMID:24192753
New Ionospheric Interaction Experiments
NASA Astrophysics Data System (ADS)
Sheerin, J. P.
Current upgrades to both the HF transmitter and diagnostic capabilities at the HAARP facility near Gakona, AK will permit a new generation ionospheric interaction experiments. We explore some of the new phenomena accessible with significantly increased ERP. Large-scale long-lived density structures induced by the HF pump in the ionospheric plasma are investigated. Long-lived density structures which convect with the ambient ionosphere, may serve as tracers for ionospheric flows and fields. Recent advances in HF and VHF radar diagnostics available for HAARP experiments, permit plasma wave detection and monitoring. We survey the mode structures expected with the next generation of high intensity experiments. Together with existing complementary diagnostics such as stimulated HF emissions and optical effects, these data will provide unprecedented views of highly nonlinear phenomena induced by high intensity RF radiation in the ionosphere.
Drugging Membrane Protein Interactions
Yin, Hang; Flynn, Aaron D.
The majority of therapeutics target membrane proteins, accessible on the surface of cells, to alter cellular signaling. Cells use membrane proteins to transduce signals into cells, transport ions and molecules, bind the cell to a surface or substrate, and catalyze reactions. Newly devised technologies allow us to drug conventionally "undruggable" regions of membrane proteins, enabling modulation of protein–protein, protein–lipid, and protein–nucleic acid interactions. In this review, we survey the state of the art in high-throughput screening and rational design in drug discovery, and we evaluate the advances in biological understanding and technological capacity that will drive pharmacotherapy forward against unorthodox membrane protein targets. PMID:26863923
Three dimensional interactive display
NASA Technical Reports Server (NTRS)
Vranish, John M. (Inventor)
A three-dimensional (3-D) interactive display and method of forming the same, includes a transparent capaciflector (TC) camera formed on a transparent shield layer on the screen surface. A first dielectric layer is formed on the shield layer. A first wire layer is formed on the first dielectric layer. A second dielectric layer is formed on the first wire layer. A second wire layer is formed on the second dielectric layer. Wires on the first wire layer and second wire layer are grouped into groups of parallel wires with a turnaround at one end of each group and a sensor pad at the opposite end. An operational amplifier is connected to each of the sensor pads and the shield pad biases the pads and receives a signal from connected sensor pads in response to intrusion of a probe. The signal is proportional to probe location with respect to the monitor screen.
NASA Technical Reports Server (NTRS)
Buckley, D. H.
There is a wide variety of situations wherein metals are in solid state contact with dielectric materials. The paper reviews some of the factors that influence solid state interactions for metals in contact with dielectric surfaces. Since surfaces play an important part in these reactions, the use of analytical tools in characterizing surfaces is discussed. Adhesion, friction, and wear are utilized as indicators of the nature of interfacial bonding between metals and dielectrics can be effectively determined with adhesion and friction force measurements. Films present on the surface, such as oxygen or water vapor, markedly alter adhesive bond strength which in turn affects friction force and interfacial fracture when attempts are made to separate the contact regions. Analytical surface tools such as the field ion microscope, Auger emission spectroscopy, and X-ray photoelectron spectroscopy are very effective in providing insight into the effect of contact on the surfaces of metals and dielectrics.
Interlayer interactions in graphites
NASA Astrophysics Data System (ADS)
Chen, Xiaobin; Tian, Fuyang; Persson, Clas; Duan, Wenhui; Chen, Nan-Xian
Based on ab initio calculations of both the ABC- and AB-stacked graphites, interlayer potentials (i.e., graphene-graphene interaction) are obtained as a function of the interlayer spacing using a modified Möbius inversion method, and are used to calculate basic physical properties of graphite. Excellent consistency is observed between the calculated and experimental phonon dispersions of AB-stacked graphite, showing the validity of the interlayer potentials. More importantly, layer-related properties for nonideal structures (e.g., the exfoliation energy, cleave energy, stacking fault energy, surface energy, etc.) can be easily predicted from the interlayer potentials, which promise to be extremely efficient and helpful in studying van der Waals structures.
Interactive surface grid generation
NASA Technical Reports Server (NTRS)
Luh, Raymond Ching-Chung; Pierce, Lawrence E.; Yip, David
This paper describes a surface grid generation tool called S3D. It is the result of integrating a robust and widely applicable interpolation technique with the latest in workstation technology. Employing the use of a highly efficient and user-friendly graphical interface, S3D permits real-time interactive analyses of surface geometry data and facilitates the construction of surface grids for a wide range of applications in Computational Fluid Dynamics (CFD). The design objectives are for S3D to be stand-alone and easy to use so that CFD analysts can take a hands-on approach toward most if not all of their surface grid generation needs. Representative examples of S3D applications are presented in describing the various elements involved in the process.
Synchronization and hydrodynamic interactions
NASA Astrophysics Data System (ADS)
Powers, Thomas; Qian, Bian; Breuer, Kenneth
Cilia and flagella commonly beat in a coordinated manner. Examples include the flagella that Volvox colonies use to move, the cilia that sweep foreign particles up out of the human airway, and the nodal cilia that set up the flow that determines the left-right axis in developing vertebrate embryos. In this talk we present an experimental study of how hydrodynamic interactions can lead to coordination in a simple idealized system: two nearby paddles driven with fixed torques in a highly viscous fluid. The paddles attain a synchronized state in which they rotate together with a phase difference of 90 degrees. We discuss how synchronization depends on system parameters and present numerical calculations using the method of regularized stokeslets.
Metzler, R; Kinzel, W; Kanter, I
Several scenarios of interacting neural networks which are trained either in an identical or in a competitive way are solved analytically. In the case of identical training each perceptron receives the output of its neighbor. The symmetry of the stationary state as well as the sensitivity to the used training algorithm are investigated. Two competitive perceptrons trained on mutually exclusive learning aims and a perceptron which is trained on the opposite of its own output are examined analytically. An ensemble of competitive perceptrons is used as decision-making algorithms in a model of a closed market (El Farol Bar problem or the Minority Game. In this game, a set of agents who have to make a binary decision is considered.); each network is trained on the history of minority decisions. This ensemble of perceptrons relaxes to a stationary state whose performance can be better than random. PMID:11088736
NASA Astrophysics Data System (ADS)
Ursu, Marian F.
Looking back over the past 25 years, the impressive developments in information and communication technologies generated a booming popularity of the new forms of media consumption that allow for interactivity and mobility, such as Web information and entertainment and games. This was and still is particularly evident within the younger generation, who are the most avid adopters of both new technologies and new forms of media consumption (Schadler 2006; KPMG 2007). When asked, in 2006, which device they could not live without, 37% mentioned their PC, 26% their mobile phone, whereas only 17% mentioned their TVs (Schadler 2006); and all these were before the launch of products such as the iPhone, which offer increasing flexibility and mobility of the media experiences.
Critical Density Interaction Studies
Young, P; Baldis, H A; Cheung, P; Rozmus, W; Kruer, W; Wilks, S; Crowley, S; Mori, W; Hansen, C
Experiments have been performed to study the propagation of intense laser pulses to high plasma densities. The issue of self-focusing and filamentation of the laser pulse as well as developing predictive capability of absorption processes and x-ray conversion efficiencies is important for numerous programs at the Laboratory, particularly Laser Program (Fast Ignitor and direct-drive ICF) and D&NT (radiography, high energy backlighters and laser cutting). Processes such as resonance absorption, profile modification, linear mode conversion, filamentation and stimulated Brillouin scattering can occur near the critical density and can have important effects on the coupling of laser light to solid targets. A combination of experiments have been used to study the propagation of laser light to high plasma densities and the interaction physics of intense laser pulses with solid targets. Nonparaxial fluid codes to study nonstationary behavior of filamentation and stimulated Brillouin scattering at high densities have also been developed as part of this project.
Inferring biotic interactions from proxies.
Morales-Castilla, Ignacio; Matias, Miguel G; Gravel, Dominique; Araújo, Miguel B
Inferring biotic interactions from functional, phylogenetic and geographical proxies remains one great challenge in ecology. We propose a conceptual framework to infer the backbone of biotic interaction networks within regional species pools. First, interacting groups are identified to order links and remove forbidden interactions between species. Second, additional links are removed by examination of the geographical context in which species co-occur. Third, hypotheses are proposed to establish interaction probabilities between species. We illustrate the framework using published food-webs in terrestrial and marine systems. We conclude that preliminary descriptions of the web of life can be made by careful integration of data with theory. PMID:25922148
Coulomb interactions and fermion condensation
Capstick, S.; Cutkosky, R.E.; Joensen, M.A. ); Wang, K.C. )
The influence of the Coulomb interaction in states containing massless and flavorless fermion-antifermion pairs is studied, using a continuum formulation within the finite volume {ital S}{sup 3}. Several different forms for the Coulomb interaction are examined, including confining potentials as well as nonconfining potentials. The calculations show that if the interaction is strong enough, the Coulomb interaction leads to condensation of pairs, and that this condensation has a chiral character. The condensation does not depend on whether the interaction is confining. It is found that simplified variational approximations are not accurate enough for an adequate description of the states.
Platelet Interaction with Bacteria
Clawson, C. C.
The interaction of several common strains of bacteria with rabbit or human platelets in vitro has been examined sequentially with scanning and transmission electron microscopy. Bacteria were added to platelets in their native plasma or to washed platelets in a balanced salt solution at ratios of about 1:1 or at low bacteria to platelet ratios (down to 1:100). The platelet-bacterial interaction (PBI) was studied with recording nephelometry. Matched samples were fixed for microscopy at various points in the aggregation response. The results support these conclusions: a) Bacteria stimulate platelet aggregation by direct contact and adhesion with the platelet surface. b) Adhesion between the two cell types requires divalent cations, occurs through fusion of normal cell-surface coats and appears identical in the presence or absence of extracellular plasma protein. c) The morphologic transformation of platelets during PBI is identical to that produced by collagen. d) During PBI the bacteria are incorporated into the forming platelet aggregates and reside predominantly intercellularly. e) Phagocytosis of bacteria by a single platelet is very rare. f) Bacteria which have resided within platelet aggregates for one hour are unaltered morphologically. g) PBI occurs even at very low bacterial numbers and produces platelet-bacterial aggregates in small numbers without stimulating generalized platelet aggregation. Methods for concentration of thrombocytopenic plasma and washing human platelets are presented. ImagesFig 6Fig 7Fig 8Fig 9Fig 10Fig 11Fig 1Fig 2Fig 12Fig 13Fig 3Fig 14Fig 4Fig 5 PMID:4632008
Interactive Projector as an Interactive Teaching Tool in the Classroom: Evaluating Teaching Efficiency and Interactivity
ERIC Educational Resources Information Center
Liu, Li-Ying; Cheng, Meng-Tzu
This study reports on a measurement that is used to investigate interactivity in the classrooms and examines the impact of integrating the interactive projector into middle school science classes on classroom interactivity and students' biology learning. A total of 126 7th grade Taiwanese students were involved in the study and quasi-experimental…
Developing a general interaction potential for hydrophobic and hydrophilic interactions.
Donaldson, Stephen H; Røyne, Anja; Kristiansen, Kai; Rapp, Michael V; Das, Saurabh; Gebbie, Matthew A; Lee, Dong Woog; Stock, Philipp; Valtiner, Markus; Israelachvili, Jacob
We review direct force measurements on a broad class of hydrophobic and hydrophilic surfaces. These measurements have enabled the development of a general interaction potential per unit area, W(D) = -2γ(i)Hy exp(-D/D(H)) in terms of a nondimensional Hydra parameter, Hy, that applies to both hydrophobic and hydrophilic interactions between extended surfaces. This potential allows one to quantitatively account for additional attractions and repulsions not included in the well-known combination of electrostatic double layer and van der Waals theories, the so-called Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The interaction energy is exponentially decaying with decay length D(H) ≈ 0.3-2 nm for both hydrophobic and hydrophilic interactions, with the exact value of D(H) depending on the precise system and conditions. The pre-exponential factor depends on the interfacial tension, γ(i), of the interacting surfaces and Hy. For Hy > 0, the interaction potential describes interactions between partially hydrophobic surfaces, with the maximum hydrophobic interaction (i.e., two fully hydrophobic surfaces) corresponding to Hy = 1. Hydrophobic interactions between hydrophobic monolayer surfaces measured with the surface forces apparatus (SFA) are shown to be well described by the proposed interaction potential. The potential becomes repulsive for Hy < 0, corresponding to partially hydrophilic (hydrated) interfaces. Hydrated surfaces such as mica, silica, and lipid bilayers are discussed and reviewed in the context of the values of Hy appropriate for each system. PMID:25072835
Galactic Interactions and Dark Matter
NASA Astrophysics Data System (ADS)
Willig, T.; Storrs, A.
In studying galactic interactions is it possible with present instrumentation to find evidence of dark matter within these interactions? The present theory is that dark matter and its gravitational force is what accounts for much of spiral galaxy rotation curves. If this is true, we should be able to find evidence of dark matter when two galaxies (one being a spiral galaxy) interact. Several pairs of interacting galaxies in various stages of interaction will be studied. In addition, several non interacting spiral galaxies will be studied for comparisons. We present analysis of a variety of archival imaging data from radio maps through x-ray images in an attempt to observe the effects of dark matter in galaxy interactions.
Weak Interactions and Instability Cascades.
Kadoya, Taku; McCann, Kevin S
Food web theory states that a weak interactor which is positioned in the food web such that it tends to deflect, or mute, energy away from a potentially oscillating consumer-resource interaction often enhances community persistence and stability. Here we examine how adding other weak interactions (predation/harvesting) on the stabilizing weak interactor alters the stability of food web using a set of well-established food web models/modules. We show that such "weak on weak" interaction chains drive an indirect dynamic cascade that can rapidly ignite a distant consumer-resource oscillator. Nonetheless, we also show that the "weak on weak" interactions are still more stable than the food web without them, and so weak interactions still generally act to stabilize food webs. Rather, these results are best interpreted to say that the degree of the stabilizing effect of a given important weak interaction can be severely compromised by other weak interactions (including weak harvesting). PMID:26219561
Arc electrode interaction study
NASA Technical Reports Server (NTRS)
Zhou, X.; Berns, D.; Heberlein, J.
The project consisted of two parts: (1) the cathode interaction studies which were a continuation of previous work and had the objective of increasing our understanding of the microscopic phenomena controlling cathode erosion in arc jet thrusters, and (2) the studies of the anode attachment in arc jet thrusters. The cathode interaction studies consisted of (1) a continuation of some modeling work in which the previously derived model for the cathode heating was applied to some specific gases and electrode materials, and (2) experimental work in which various diagnostics was applied to the cathode. The specific diagnostics used were observation of the cathode tip during arcing using a Laser Strobe Video system in conjunction with a tele-microscope, a monochromator with an optical multichannel analyzer for the determination of the cathode temperature distribution, and various ex situ materials analysis methods. The emphasis of our effort was shifted to the cathode materials analysis because a parallel project was in place during the second half of 1993 with a visiting scientist pursuing arc electrode materials studies. As a consequence, the diagnostic investigations of the arc in front of the cathode had to be postponed to the first half of 1994, and we are presently preparing these measurements. The results of last year's study showed some unexpected effects influencing the cathode erosion behavior, such as increased erosion away from the cathode tip, and our understanding of these effects should improve our ability to control cathode erosion. The arc jet anode attachment studies concentrated on diagnostics of the instabilities in subsonic anode attachment arc jet thrusters, and were supplemental measurements to work which was performed by one of the authors who spent the summer as an intern at NASA Lewis Research Center. A summary of the results obtained during the internship are included because they formed an integral part of the study. Two tasks for 1994, the
Antiproton-nucleus interaction
NASA Astrophysics Data System (ADS)
Cugnon, J.; Vandermeulen, J.
The antiproton-nucleus physics is reviewed. On the experimental side, the recent results obtained at the LEAR, BNL and KEK facilities are analyzed. A brief summary of the main pp and pn experimental data is also given. The antiproton-nucleus interaction can lead to elasic, inelastic and charge exchange scattering and to annihilation. The latter is very dominant. The scattering cross-sections are usually analyzed in terms of complex potential models. The relationship between potentials, charge conjugation and Dirac phenomenology is discussed. Much emphasis is put on the dynamics of the antiproton annihilation on nuclei. The energy transfer, pion absorption and target response are analyzed within the intranuclear cascade model. Special interest is devoted to strangeness production, hypernucleus formation and possible annihilation on two nucleons. Signatures for this new process are searched in experimental data. Finally, the highly debated question of quark-gluon formation is analyzed. Cet article constitue une revue de la physique antiproton-noyau. Du point de vue expérimental, cette revue porte particulièrement sur les récents résultats obtenus à LEAR, BNL et KEK. On y a aussi inclus une mise à jour des faits expérimentaux principaux pour pp et pn. L'interaction antiproton-noyau conduit à la diffusion élastique, inélastique et d'xA9change de charge et à des processus d'annihilation. Habituellement, les expériences de diffusion sont analysées en termes de potentiels complexes. La relation entre ces potentiels, la conjugaison de charge et la phénoménologie de Dirac est discutée. On s'est particulièrement intéressé à la dynamique de l'annihilation d'antiprotons sur des noyaux. Le transfert d'énergie, l'absorption de pions et la réponse de la cible sont analysés dans le cadre du modèle de cascade intranucléaire. Certains autres points sont discutés plus en détail: la production d'étrangeté, la formation d'hypernoyaux et l'annihilation sur
E.S. Gaffney
This report documents the model of events associated with a potential intrusion of magma from a volcanic dike into a drift or drifts in the Yucca Mountain Nuclear Waste Repository. The following topics are included in this report: (1) A discussion of dike propagation, which provides the basis for describing the path that a representative dike, or swarm of dikes, would follow during an event. (2) A discussion of magma flow, which evaluates the interaction at the junction of the propagating dike with the drift and the movement of magmatic products into and down drifts and, potentially, through a drift to the surface by way of access drift or a secondary dike opened up along the drift. (3) A discussion of gas flow and conductive cooling of a magma-filled drift, describing how an adjacent drift that has not been intersected by a dike could be affected by post-intrusion phenomena. Note that a gas flow analysis is also addressed in ''Igneous Intrusion Impacts on Waste Form and Waste Packages'' (BSC 2003 [DIRS 161810]), and those results are consistent with the results presented in this report.
Wolbachia filarial interactions.
Taylor, Mark J; Voronin, Denis; Johnston, Kelly L; Ford, Louise
Wolbachia pipientis is a widespread intracellular bacterial symbiont of arthropods and is common in insects. One of their more exotic and unexpected hosts is the filarial nematodes, notable for the parasites responsible for onchocerciasis (river blindness), lymphatic filariasis (elephantiasis) and dirofilariasis (heartworm). Wolbachia are only present in a subgroup of the filarial nematodes and do not extend to other groups of nematodes either parasitic or free-living. In the medically and veterinary important species that host Wolbachia, the symbiont has become an essential partner to key biological processes in the life of the nematode to the point where antibiotic elimination of the bacteria leads to a potent and effective anti-filarial drug treatment. We review the cellular and molecular basis of Wolbachia filarial interactions and highlight the key processes provided by the endosymbiont upon which the nematodes have become entirely dependent. This dependency is primarily restricted to periods of the lifecycle with heavy metabolic demands including growth and development of larval stages and embryogenesis in the adult female. Also, the longevity of filarial parasites is compromised following depletion of the symbiont, which for the first time has delivered a safe and effective treatment to kill adult parasites with antibiotics. PMID:23210448
"Interactive Classification Technology"
NASA Technical Reports Server (NTRS)
deBessonet, Cary
The investigators are upgrading a knowledge representation language called SL (Symbolic Language) and an automated reasoning system called SMS (Symbolic Manipulation System) to enable the technologies to be used in automated reasoning and interactive classification systems. The overall goals of the project are: a) the enhancement of the representation language SL to accommodate multiple perspectives and a wider range of meaning; b) the development of a sufficient set of operators to enable the interpreter of SL to handle representations of basic cognitive acts; and c) the development of a default inference scheme to operate over SL notation as it is encoded. As to particular goals the first-year work plan focused on inferencing and.representation issues, including: 1) the development of higher level cognitive/ classification functions and conceptual models for use in inferencing and decision making; 2) the specification of a more detailed scheme of defaults and the enrichment of SL notation to accommodate the scheme; and 3) the adoption of additional perspectives for inferencing.
Atmospheric Ball Plasma Interactions
NASA Astrophysics Data System (ADS)
Wurden, C. J. V.; Wurden, G. A.
Free-floating atmospheric pressure copper hydroxyl ball plasmas have been studied in air and helium atmospheres, using still and high speed photography (up to 20,000 fps), collimated photodiodes, and spectroscopy. A fine boundary layer between the greenish Cu-OH cloud, and the air, is orange in color. However, when the discharge is initiated into a helium atmosphere, the boundary layer is no longer visible, suggesting that the visible boundary was caused by interactions with oxygen. We have studied scaling of the 10-cm diameter ball plasmas with both the size of the water bucket, and the applied discharge voltage, over the range of 500-5000 volts. When looking at the initial spider-leg breakdown above the water surface, the ratio of H-alpha to H-beta lines suggests a temperature of ˜0.3 eV. This is also consistent with the presence of molecular lines of OH, and perhaps CuOH2 in the rising cloud. The cloud is affected by, but can penetrate through an aluminum window screen mesh.
Interactions between electromagnetic fields
NASA Astrophysics Data System (ADS)
Schwan, H. P.
We applied for this grant to support a workshop at Erice, Italy. This workshop has been commonly called Erice School and the main subject of this workshop is the interaction of electromagnetic fields with biological cells and molecules. The grant from ONR enabled us to invite American scientists to participants in this workshop and deliver scientific papers. The duration of the Erice School was ten days. Therefore, we had sufficient time to discuss the problems of electromagnetic radiations. Vigorous discussions took place during official sessions and during private conversations. The participants of this workshop are mostly those who have been active in the research on bioelectromagnetics, but there are some numbers of speakers who discussed the basic electrical and magnetic properties of polyelectrolytes, biological membranes and tissue. The workshop was unique in that there were participants with a variety of training backgrounds. This enabled us to exchange the information between applied scientists and basic scientists. Also, active exchanges of opinions took place between biological scientists and physical scientists.
Influenza-Sediment Interactions
NASA Astrophysics Data System (ADS)
Trusiak, A.; Block, K. A.; Katz, A.; Gottlieb, P.; Alimova, A.; Galarza, J.; Wei, H.; Steiner, J. C.
A typical water fowl can secrete 1012 influenza virions per day. Therefore it is not unexpected that influenza virions interact with sediments in the water column. The influence of sediments on avian influenza virions is not known. With the threat of avian influenza emerging into the human population, it is crucial to understand virus survivability and residence time in a body of water. Influenza and clay sediments are colloidal particles and thus aggregate as explained by DLVO (Derjaguin & Landau, Verwey & Overbeek) theory. Of great importance is an understanding of the types of particulate or macromolecular components that bind the virus particles, and whether the virus remains biologically active. We present results of hetero-aggregation and transmission electron microscopy experiments performed with influenza A/PR8/38. Influenza particles are suspended with sediment and minimal nutrients for several days, after which the components are evaluated to determine influenza concentration and survivability. Transmission electron microscopy results are reported on the influenza-sediment aggregates to elucidate structure and morphology of the components.
P. Mariner
As directed by written development plan (CRWMS M&O 1999a), a sub-model of seepage/backfill interactions is developed and presented in this document to support the Engineered Barrier System (EBS) Physical and Chemical Environment Model. The purpose of this analysis is to assist Performance Assessment Operations (PAO) and the Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift. In this analysis, a conceptual model is developed to provide PAO a more detailed and complete in-drift geochemical model abstraction and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). The development plan calls for a sub-model that evaluates the effect on water chemistry of chemical reactions between water that enters the drift and backfill materials in the drift. The development plan specifically requests an evaluation of the following important chemical reaction processes: dissolution-precipitation, aqueous complexation, and oxidation-reduction. The development plan also requests the evaluation of the effects of varying seepage and drainage fluxes, varying temperature, and varying evaporation and condensation fluxes. Many of these effects are evaluated in a separate Analysis/Model Report (AMR), ''Precipitates Salts Analysis AMR'' (CRWMS M&O 2000), so the results of that AMR are referenced throughout this AMR.
Hydrogen interactions with metals
NASA Technical Reports Server (NTRS)
Mclellan, R. B.; Harkins, C. G.
Review of the literature on the nature and extent of hydrogen interactions with metals and the role of hydrogen in metal failure. The classification of hydrogen-containing systems is discussed, including such categories as covalent hydrides, volatile hydrides, polymeric hydrides, and transition metal hydride complexes. The use of electronegativity as a correlating parameter in determining hydride type is evaluated. A detailed study is made of the thermodynamics of metal-hydrogen systems, touching upon such aspects as hydrogen solubility, the positions occupied by hydrogen atoms within the solvent metal lattice, the derivation of thermodynamic functions of solid solutions from solubility data, and the construction of statistical models for hydrogen-metal solutions. A number of theories of hydrogen-metal bonding are reviewed, including the rigid-band model, the screened-proton model, and an approach employing the augmented plane wave method to solve the one-electron energy band problem. Finally, the mechanism of hydrogen embrittlement is investigated on the basis of literature data concerning stress effects and the kinetics of hydrogen transport to critical sites.
Strongly interacting ultracold polar molecules
NASA Astrophysics Data System (ADS)
Gadway, Bryce; Yan, Bo
This paper reviews recent advances in the study of strongly interacting systems of dipolar molecules. Heteronuclear molecules feature large and tunable electric dipole moments, which give rise to long-range and anisotropic dipole–dipole interactions. Ultracold samples of dipolar molecules with long-range interactions offer a unique platform for quantum simulations and the study of correlated many-body physics. We provide an introduction to the physics of dipolar quantum gases, both electric and magnetic, and summarize the multipronged efforts to bring dipolar molecules into the quantum regime. We discuss in detail the recent experimental progress in realizing and studying strongly interacting systems of polar molecules trapped in optical lattices, with particular emphasis on the study of interacting spin systems and non-equilibrium quantum magnetism. Finally, we conclude with a brief discussion of the future prospects for studies of strongly interacting dipolar molecules.
Nanobiotechnology: protein-nanomaterial interactions.
Kane, Ravi S; Stroock, Abraham D
We review recent research that involves the interaction of nanomaterials such as nanoparticles, nanowires, and carbon nanotubes with proteins. We begin with a focus on the fundamentals of the structure and function of proteins on nanomaterials. We then review work in three areas that exploit these interactions: (1) sensing, (2) assembly of nanomaterials by proteins and proteins by nanomaterials, and (3) interactions with cells. We conclude with the identification of challenges and opportunities for the future. PMID:17335286
Final State Interactions in GENIE
NASA Astrophysics Data System (ADS)
Dytman, S. A.; Meyer, A. S.
Final state interactions (FSI) are an important part of all neutrino event generators because modern detectors are made of nuclei to maximize count rate. The incident neutrino will interact with one (or two) nucleons but the final state can be quite different because the hadrons will have further interactions in the residual nucleus. This has historically been one of the major differences between event generators. GENIE will now have 2 FSI codes which allow interesting comparisons for the first time.
A relativistic description of the quasifree radiative pion-capture reaction on nuclei
NASA Astrophysics Data System (ADS)
Johansson, J. I.; Sherif, H. S.
We present a relativistic model for the reaction A( π+, γp) A - 1. This is an extension of our recent model for negative-pion photoproduction. The interaction of the pion with the target nucleon is comprised of the set of Born terms arising from the pseudovector form of the pion-nucleon interaction lagrangian, as well as s- and u-channel diagrams involving the propagation of the Δ(1232). The bound and continuum nucleons are described by solutions of the Dirac equation with appropriate scalar and vector potentials, while the pion wave function is a solution of the Klein-Gordon equation containing a pion-nucleus optical potential. Calculations of the triple differential cross section {d3σ }/{dω p dω γdEγ } as well as the polarization of the final proton are presented for the kinematics of TRIUMF experiment 550. Under appropriate kinematic conditions the contribution of the Δ(1232) is found to be dominant in this reaction. The results are sensitive to the choice of pion-nucleus optical potential but are not very sensitive to the nucleon interactions with the nucleus. We obtain qualitative agreement with data from TRIUMF experiment 550.
Hadronic electric dipole moments in R-parity violating supersymmetry
Faessler, Amand; Gutsche, Thomas; Lyubovitskij, Valery E.; Kovalenko, Sergey
We calculate the electric dipole moments (EDM) of the neutral {sup 199}Hg atom, neutron and deuteron within a generic R-parity violating SUSY model (Re{sub p} SUSY) on the basis of a one-pion-exchange model with CP-odd pion-nucleon interactions. We consider two types of the Re{sub p} SUSY contributions to the above hadronic EDMs: via the quark chromoelectric dipole moments (CEDM) and CP-violating 4-quark interactions. We demonstrate that the former contributes to all the three studied EDMs while the latter appears only in the nuclear EDMs via the CP-odd nuclear forces. We find that the Re{sub p} SUSY induced 4-quark interactions arise at tree level through the sneutrino exchange and involve only s and b quarks. Therefore, their effect in hadronic EDMs is determined by the strange and bottom-quark sea of the nucleon. From the null experimental results on the hadronic EDMs we derive the limits on the imaginary parts of certain products Im({lambda}{sup '}{lambda}{sup '}*) of the trilinear Re{sub p}-couplings and show that the currently best limits come from the {sup 199}Hg EDM experiments. We demonstrate that some of these limits are better than those existing in the literature. We argue that future storage ring experiments on the deuteron EDM are able to improve these limits by several orders of magnitude.
Water-Mediated Hydrophobic Interactions.
Ben-Amotz, Dor
Hydrophobic interactions are driven by the combined influence of the direct attraction between oily solutes and an additional water-mediated interaction whose magnitude (and sign) depends sensitively on both solute size and attraction. The resulting delicate balance can lead to a slightly repulsive water-mediated interaction that drives oily molecules apart rather than pushing them together and thus opposes their direct (van der Waals) attraction for each other. As a consequence, competing solute size-dependent crossovers weaken hydrophobic interactions sufficiently that they are only expected to significantly exceed random thermal energy fluctuations for processes that bury more than ∼1 nm(2) of water-exposed area. PMID:27215821
Structural interaction with control systems
NASA Technical Reports Server (NTRS)
Noll, R. B.; Zvara, J.
A monograph which assesses the state of the art of space vehicle design and development is presented. The monograph presents criteria and recommended practices for determining the structural data and a mathematical structural model of the vehicle needed for accurate prediction of structure and control-system interaction; for design to minimize undesirable interactions between the structure and the control system; and for determining techniques to achieve the maximum desirable interactions and associated structural design benefits. All space vehicles are treated, including launch vehicles, spacecraft, and entry vehicles. Important structural characteristics which affect the structural model used for structural and control-system interaction analysis are given.
Interactive TV on parliament session
NASA Astrophysics Data System (ADS)
Royer, J.; Nguyen, H.; Martinot, O.; Preda, M.; Preteux, F.; Zaharia, T.
This paper introduces a new interactive mobile TV application related to parliament session. This application aims to provide additional information to mobile TV users by inserting automatically and in real-time interactive contents (complementary information, subject of the current session...) into original TV program, using MPEG-4 streaming video and extra real time information (news, events, databases... from RSS streams, Internet links...). Here, we propose an architecture based on plug-in multimedia analyzers to generate the contextual description of the media and on an interactive scene generator to dynamically create related interactive scenes. Description is implemented according to the MPEG-7 standard.
Water-Mediated Hydrophobic Interactions
NASA Astrophysics Data System (ADS)
Ben-Amotz, Dor
Hydrophobic interactions are driven by the combined influence of the direct attraction between oily solutes and an additional water-mediated interaction whose magnitude (and sign) depends sensitively on both solute size and attraction. The resulting delicate balance can lead to a slightly repulsive water-mediated interaction that drives oily molecules apart rather than pushing them together and thus opposes their direct (van der Waals) attraction for each other. As a consequence, competing solute size-dependent crossovers weaken hydrophobic interactions sufficiently that they are only expected to significantly exceed random thermal energy fluctuations for processes that bury more than ˜1 nm2 of water-exposed area.
Theoretical studies of molecular interactions
Lester, W.A. Jr.
This research program is directed at extending fundamental knowledge of atoms and molecules including their electronic structure, mutual interaction, collision dynamics, and interaction with radiation. The approach combines the use of ab initio methods--Hartree-Fock (HF) multiconfiguration HF, configuration interaction, and the recently developed quantum Monte Carlo (MC)--to describe electronic structure, intermolecular interactions, and other properties, with various methods of characterizing inelastic and reaction collision processes, and photodissociation dynamics. Present activity is focused on the development and application of the QMC method, surface catalyzed reactions, and reorientation cross sections.
RKKY interaction in bilayer graphene
NASA Astrophysics Data System (ADS)
Mohammadi, Yawar; Moradian, Rostam
We study the RKKY interaction between two magnetic impurities located on the same layer (intralayer case) or on different layers (interlayer case) in undoped bilayer graphene (BLG) in the four-bands model, by directly calculating the Green functions in the eigenvalues and eigenvectors representation. Our results show that both intra- and interlayer RKKY interactions between two magnetic impurities located on the same (opposite) sublattice are always ferromagnetic (antiferromagnetic). Furthermore we find unusual long-distance decay of the RKKY interaction in BLG. The intralyer RKKY interactions between two magnetic impurities located on the same sublattice, J AnAn(R) and J BnBn(R), decay closely as 1 /R6 and 1 /R2 at large impurity distances respectively, but when they are located on opposite sublattices the RKKY interactions exhibit 1 /R4 decays approximately. In the interlayer case, the RKKY interactions between two magnetic impurities located on the same sublattice show a decay close to 1 /R4 at large impurity distances, but if two magnetic impurities be on opposite sublattices the RKKY interactions, J A1B2(R) and J B1A2(R), decay closely as 1 /R6 and 1 /R2 respectively. Both intra- and interlayer RKKY interactions have anisotropic oscillatory factors which for intralayer case is equal to that for single layer graphene (SLG). Our results at weak and strong interlayer coupling limits reduce to the RKKY interaction of SLG and that of BLG in the two-bands approximation respectively.
Relativistic interactions and realistic applications
Hoch, T.; Madland, D.; Manakos, P.; Mannel, T.; Nikolaus, B.A.; Strottman, D. |
A four-fermion-coupling Lagrangian (relativistic Skyrme-type) interaction has been proposed for relativistic nuclear structure calculations. This interaction, which has the merit of simplicity, is from the outset tailored as an effective interaction for relativistic Hartree-Fock calculations. Various extensions of such a model are discussed and compared with Walecka`s meson-nucleon mean field approach. We also present results of the calculation of nuclear ground state properties with an extended (density dependent) version of the four fermion interaction in a relativistic Hartree-Fock approximation.
The Ontogenesis of Telephone Interaction.
ERIC Educational Resources Information Center
Mininni, Giuseppe
A longitudinal study of the acquisition of telephone skills among five preschool children analyzed play telephone interactions and real telephone conversations for similarities and changes in performance. (MSE)
Tulin, Sean
The particle physics nature of dark matter (DM) can leave an imprint on the structure of Universe. If DM has a sizable cross section for self-interactions (much larger than the typical weak scale cross section), this can affect the density profiles of DM halos. Moreover, there exist long-standing discrepancies on small scales between astrophysical observations and predictions from N-body simulations of collisionless DM, which suggests that DM may be self-interacting. Here, we review these discrepancies, we discuss the particle physics implications of self-interacting DM, and we show that DM self-interactions have interesting implications for direct and indirect detection searches.
Why Interactivity Works: Interactive Priming of Mental Rotation
ERIC Educational Resources Information Center
Smith, Glenn Gordon; Olkun, Sinan
This study has important implications for microworlds such as Logo, HyperGami, and Newton's World, which use interaction to learn spatial mental models for science, math, geometry, etc. This study tested the hypothesis that interactively rotating (dragging) virtual shapes primes mental rotation. The independent variable was observation vs.…
Functions of Interactive Visual Representations in Interactive Mathematical Textbooks
ERIC Educational Resources Information Center
Yerushalmy, Michal
The paper explores changes in technology that have implications for the teaching and learning of school mathematics. To this end, it examines aspects of interactive mathematical textbooks; specifically it analyzes functions authors may intend to be carried out by embedded interactive diagrams. The paper analyzes theoretical as well as practical…
NASA Technical Reports Server (NTRS)
Bauer, F. H.
The Interactive Controls Analysis (INCA) program was developed to provide a user friendly environment for the design and analysis of linear control systems, primarily feedback control systems. INCA is designed for use with both small and large order systems. Using the interactive graphics capability, the INCA user can quickly plot a root locus, frequency response, or time response of either a continuous time system or a sampled data system. The system configuration and parameters can be easily changed, allowing the INCA user to design compensation networks and perform sensitivity analysis in a very convenient manner. A journal file capability is included. This stores an entire sequence of commands, generated during an INCA session into a file which can be accessed later. Also included in INCA are a context-sensitive help library, a screen editor, and plot windows. INCA is robust to VAX-specific overflow problems. The transfer function is the basic unit of INCA. Transfer functions are automatically saved and are available to the INCA user at any time. A powerful, user friendly transfer function manipulation and editing capability is built into the INCA program. The user can do all transfer function manipulations and plotting without leaving INCA, although provisions are made to input transfer functions from data files. By using a small set of commands, the user may compute and edit transfer functions, and then examine these functions by using the ROOT_LOCUS, FREQUENCY_RESPONSE, and TIME_RESPONSE capabilities. Basic input data, including gains, are handled as single-input single-output transfer functions. These functions can be developed using the function editor or by using FORTRAN- like arithmetic expressions. In addition to the arithmetic functions, special functions are available to 1) compute step, ramp, and sinusoid functions, 2) compute closed loop transfer functions, 3) convert from S plane to Z plane with optional advanced Z transform, and 4) convert from Z
Dougherty, Dennis A
The chemistry community now recognizes the cation-π interaction as a major force for molecular recognition, joining the hydrophobic effect, the hydrogen bond, and the ion pair in determining macromolecular structure and drug-receptor interactions. This Account provides the author's perspective on the intellectual origins and fundamental nature of the cation-π interaction. Early studies on cyclophanes established that water-soluble, cationic molecules would forego aqueous solvation to enter a hydrophobic cavity if that cavity was lined with π systems. Important gas phase studies established the fundamental nature of the cation-π interaction. The strength of the cation-π interaction (Li(+) binds to benzene with 38 kcal/mol of binding energy; NH4(+) with 19 kcal/mol) distinguishes it from the weaker polar-π interactions observed in the benzene dimer or water-benzene complexes. In addition to the substantial intrinsic strength of the cation-π interaction in gas phase studies, the cation-π interaction remains energetically significant in aqueous media and under biological conditions. Many studies have shown that cation-π interactions can enhance binding energies by 2-5 kcal/mol, making them competitive with hydrogen bonds and ion pairs in drug-receptor and protein-protein interactions. As with other noncovalent interactions involving aromatic systems, the cation-π interaction includes a substantial electrostatic component. The six (four) C(δ-)-H(δ+) bond dipoles of a molecule like benzene (ethylene) combine to produce a region of negative electrostatic potential on the face of the π system. Simple electrostatics facilitate a natural attraction of cations to the surface. The trend for (gas phase) binding energies is Li(+) > Na(+) > K(+) > Rb(+): as the ion gets larger the charge is dispersed over a larger sphere and binding interactions weaken, a classical electrostatic effect. On other hand, polarizability does not define these interactions. Cyclohexane is
CONSPECTUS The chemistry community now recognizes the cation-π interaction as a major force for molecular recognition, joining the hydrophobic effect, the hydrogen bond, and the ion pair in determining macromolecular structure and drug-receptor interactions. This Account provides the author's perspective on the intellectual origins and fundamental nature of the cation-π interaction. Early studies on cyclophanes established that water-soluble, cationic molecules would forgo aqueous solvation to enter a hydrophobic cavity if that cavity was lined with π systems. Important gas phase studies established the fundamental nature of the cation-π interaction. The strength of the cation-π interaction – Li+ binds to benzene with 38 kcal/mol of binding energy; NH4+ with 19 kcal/mol– distinguishes it from the weaker polar-π interactions observed in the benzene dimer or water-benzene complexes. In addition to the substantial intrinsic strength of the cation-π interaction in gas phase studies, the cation-π interaction remains energetically significant in aqueous media and under biological conditions. Many studies have shown that cation-π interactions can enhance binding energies by 2 – 5 kcal/mol, making them competitive with hydrogen bonds and ion pairs in drug-receptor and protein-protein interactions. As with other noncovalent interactions involving aromatic systems, the cation-π interaction includes a substantial electrostatic component. The six (four) Cδ−–Hδ+ bond dipoles of a molecule like benzene (ethylene) combine to produce a region of negative electrostatic potential on the face of the π system. Simple electrostatics facilitate a natural attraction of cations to the surface. The trend for (gas phase) binding energies is Li+>Na+>K+>Rb+: as the ion gets larger the charge is dispersed over a larger sphere and binding interactions weaken, a classical electrostatic effect. On other hand, polarizability does not define these interactions. Cyclohexane
Interact - Access to the Arctic
NASA Astrophysics Data System (ADS)
Johansson, M.; Callaghan, T. V.
INTERACT is currently a network of 50 terrestrial research stations from all Arctic countries, but is still growing. The network was inaugurated in January 2011 when it received an EU 7th Framework award. INTERACT's main objective is to build capacity for identifying, understanding, predicting and responding to diverse environmental changes throughout the wide environmental and land-use envelopes of the Arctic. Implicit in this objective is the task to build capacity for monitoring, research, education and outreach. INTERACT is increasing access to the Arctic: 20 INTERACT research stations in Europe and Russia are offering Transnational Access and so far, 5600 person-days of access have been granted from the total of 10,000 offered. An INTERACT Station Managers' Forum facilitates a dialogue among station managers on subjects such as best practice in station management and standardised monitoring. The Station Managers' Forum has produced a unique 'one-stop-shop' for information from 45 research stations in an informative and attractive Station Catalogue that is available in hard copy and on the INTERACT web site (www.eu-interact.org). INTERACT also includes three joint research activities that are improving monitoring in remote, harsh environments and are making data capture and dissemination more efficient. Already, new equipment for measuring feedbacks from the land surface to the climate system has been installed at several locations, while best practices for sensor networking have been established. INTERACT networks with most of the high-level Arctic organisations: it includes AMAP and WWF as partners, is endorsed by IASC and CBMP, has signed MoUs with ISAC and the University of the Arctic, is a task within SAON, and contributes to the Cold Region community within GEO/GEOSS. INTERACT welcomes other interactions.
Multiple RNA interaction: beyond two.
Mneimneh, Saad; Ahmed, Syed Ali
The interaction of two RNA molecules involves a complex interplay between folding and binding that warranted recent developments in RNA-RNA interaction algorithms. However, biological mechanisms in which more than two RNAs take part in an interaction also exist. It is reasonable to believe that interactions involving multiple RNAs are generally more complex to be treated pairwise. In addition, given a pool of RNAs, it is not trivial to predict which RNAs interact without sufficient biological knowledge. Therefore, structures resulting from multiple RNA interactions often cannot be predicted by the existing algorithms that handle RNAs pairwise and may simply favor the best interacting pair. We propose a system for multiple RNA interaction that overcomes the difficulties mentioned above by formulating a combinatorial optimization problem called Pegs and Rubber Bands. A solution to this problem encodes a structure of interacting RNAs. The problem, not surprisingly, is NP-hard. However, our experiments with approximation algorithms and heuristics for the problem suggest that this formulation is adequate to predict known interaction patterns of multiple RNAs. In general, however, the optimal solution obtained does not necessarily correspond to the actual structure observed in biological experiments. Moreover, a structure produced by interacting RNAs may not be unique. We extend our approach to generate multiple suboptimal solutions. By clustering these solutions, we are able to reveal representatives that correspond to realistic structures. Specifically, our results on the U2-U6 complex with introns in the spliceosome of human/yeast and the CopA-CopT complex in E. coli are consistent with published biological structures. PMID:25680214
Educational interactive multimedia software: The impact of interactivity on learning
NASA Astrophysics Data System (ADS)
Reamon, Derek Trent
This dissertation discusses the design, development, deployment and testing of two versions of educational interactive multimedia software. Both versions of the software are focused on teaching mechanical engineering undergraduates about the fundamentals of direct-current (DC) motor physics and selection. The two versions of Motor Workshop software cover the same basic materials on motors, but differ in the level of interactivity between the students and the software. Here, the level of interactivity refers to the particular role of the computer in the interaction between the user and the software. In one version, the students navigate through information that is organized by topic, reading text, and viewing embedded video clips; this is referred to as "low-level interactivity" software because the computer simply presents the content. In the other version, the students are given a task to accomplish---they must design a small motor-driven 'virtual' vehicle that competes against computer-generated opponents. The interaction is guided by the software which offers advice from 'experts' and provides contextual information; we refer to this as "high-level interactivity" software because the computer is actively participating in the interaction. The software was used in two sets of experiments, where students using the low-level interactivity software served as the 'control group,' and students using the highly interactive software were the 'treatment group.' Data, including pre- and post-performance tests, questionnaire responses, learning style characterizations, activity tracking logs and videotapes were collected for analysis. Statistical and observational research methods were applied to the various data to test the hypothesis that the level of interactivity effects the learning situation, with higher levels of interactivity being more effective for learning. The results show that both the low-level and high-level interactive versions of the software were effective
Family Interactions and Child Psychopathology.
ERIC Educational Resources Information Center
Donenberg, Geri R.; Nelson, Dana
Previous research has not correlated parent-child interaction patterns with different forms of child psychopathology. This study examined whether parent-child interaction corresponded with childhood depression/anxiety and childhood aggression. Forty-two clinically-referred children and adolescents, 8 to 16 years old, were classified into four…
Results-Based Interaction Design
ERIC Educational Resources Information Center
Weiss, Meredith
Interaction design is a user-centered approach to development in which users and their goals are the driving force behind a project's design. Interaction design principles are fundamental to the design and implementation of effective websites, but they are not sufficient. This article argues that, to reach its full potential, a website should also…
Differential Equations Modeling Crowd Interactions
NASA Astrophysics Data System (ADS)
Borsche, Raul; Colombo, Rinaldo M.; Garavello, Mauro; Meurer, Anne
Nonlocal conservation laws are used to describe various realistic instances of crowd behaviors. First, a basic analytic framework is established through an ad hoc well-posedness theorem for systems of nonlocal conservation laws in several space dimensions interacting nonlocally with a system of ODEs. Numerical integrations show possible applications to the interaction of different groups of pedestrians and also with other agents.
Interactions between Diatoms and Bacteria
Amin, Shady A.; Parker, Micaela S.
Summary: Diatoms and bacteria have cooccurred in common habitats for hundreds of millions of years, thus fostering specific associations and interactions with global biogeochemical consequences. Diatoms are responsible for one-fifth of the photosynthesis on Earth, while bacteria remineralize a large portion of this fixed carbon in the oceans. Through their coexistence, diatoms and bacteria cycle nutrients between oxidized and reduced states, impacting bioavailability and ultimately feeding higher trophic levels. Here we present an overview of how diatoms and bacteria interact and the implications of these interactions. We emphasize that heterotrophic bacteria in the oceans that are consistently associated with diatoms are confined to two phyla. These consistent bacterial associations result from encounter mechanisms that occur within a microscale environment surrounding a diatom cell. We review signaling mechanisms that occur in this microenvironment to pave the way for specific interactions. Finally, we discuss known interactions between diatoms and bacteria and exciting new directions and research opportunities in this field. Throughout the review, we emphasize new technological advances that will help in the discovery of new interactions. Deciphering the languages of diatoms and bacteria and how they interact will inform our understanding of the role these organisms have in shaping the ocean and how these interactions may change in future oceans. PMID:22933565
Social Interactions and Mathematics Learning.
ERIC Educational Resources Information Center
Cesar, Margarida
In the 1970s W. Doise, G. Mugny and A.-N. Perret-Clermont underlined for the first time the essential role played by social interactions in cognitive development. Since then, many authors have been studying social interactions and their mediating role in knowledge apprehension and in skills acquisition. Inspired by L. Vygotsky's theory, many…
Transformations: Mobile Interaction & Language Learning
ERIC Educational Resources Information Center
Carroll, Fiona; Kop, Rita; Thomas, Nathan; Dunning, Rebecca
Mobile devices and the interactions that these technologies afford have the potential to change the face and nature of education in our schools. Indeed, mobile technological advances are seen to offer better access to educational material and new interactive ways to learn. However, the question arises, as to whether these new technologies are…
Strong interactions in air showers
Dietrich, Dennis D.
We study the role new gauge interactions in extensions of the standard model play in air showers initiated by ultrahigh-energy cosmic rays. Hadron-hadron events remain dominated by quantum chromodynamics, while projectiles and/or targets from beyond the standard model permit us to see qualitative differences arising due to the new interactions.
Verbal Patterns in Dyadic Interaction.
ERIC Educational Resources Information Center
Ayres, Joe; Ivie, Robert L.
Selected aspects of Kenneth Burke's "dramatistic" model of symbolic interaction were operationalized to describe and compare verbal patterns in transactions between five pairs of friends and five pairs of strangers. Based on Altman and Taylor's social penetration theory, it was predicted that interactants would display verbal patterns unique to…
Pathway Interaction Database (PID) —
The National Cancer Institute (NCI) in collaboration with Nature Publishing Group has established the Pathway Interaction Database (PID) in order to provide a highly structured, curated collection of information about known biomolecular interactions and key cellular processes assembled into signaling pathways.
Designing Interactive Online Nursing Courses
ERIC Educational Resources Information Center
Jain, Smita; Jain, Pawan
This study empirically tests the relation between the instructional design elements and the overall meaningful interactions among online students. Eighteen online graduate nursing courses are analyzed using bivariate and multivariate analysis techniques. Findings suggest that the quantity of meaningful interaction among learners can be improved by…
Family Interaction in Early Adolescence.
ERIC Educational Resources Information Center
Steinberg, Laurence D.; Hill, John P.
The verbal interaction of 31 middle class early adolescent boys and their parents was analyzed in order to provide information concerning adolescent autonomy. The boys were independently and reliably classified on the basis of age, physical maturity, and intellectual level. The taped interactions were coded for interruptions, talking times,…
Interactive Flow in Exercise Pedagogy
ERIC Educational Resources Information Center
Lloyd, Rebecca; Smith, Stephen
A phenomenology of the bodily experience of interactive flow adds to Csikszentmihalyi's flow theory. Whereas Csikszentmihalyi attended to teachers' and students' experiences of flow separately, this inquiry explores flow through three water-inspired layers of physical interaction between fitness professionals and their clients. Teaching fitness is…
Stable interactions via proper deformations
NASA Astrophysics Data System (ADS)
Kaparulin, D. S.; Lyakhovich, S. L.; Sharapov, A. A.
A new method is proposed for switching on interactions that are compatible with global symmetries and conservation laws of the original free theory. The method is applied to the control of stability in Lagrangian and non-Lagrangian theories with higher derivatives. By way of illustration, a wide class of stable interactions is constructed for the Pais-Uhlenbeck oscillator.
Science Education and Interactive Technology.
ERIC Educational Resources Information Center
Ittelson, John C.; Moriarty, Patricia J.
The capabilities and applications of interactive video in science education are examined in four chapters. Chapter 1 discusses technology in science education, providing a comparative evaluation of interactive videodisc (IVD) systems and the microcomputer. Specific uses of microcomputers in science education are noted. Chapter 2 is a discussion of…
Assessing Preference for Social Interactions
ERIC Educational Resources Information Center
Clay, Casey J.; Samaha, Andrew L.; Bloom, Sarah E.; Bogoev, Bistra K.; Boyle, Megan A.
We examined a procedure to assess preference for social interactions in individuals with intellectual and developmental disabilities. Preferences were identified in five individuals using a paired-choice procedure in which participants approached therapists who provided different forms of social interactions. A subsequent tracking test showed that…
Perceived Attractiveness and Classroom Interactions
ERIC Educational Resources Information Center
Algozzine, Bob
Adams and Cohen (1974) demonstrated that facial attractiveness was a salient factor in differential student-teacher interactions. This research investigates further the interaction between teachers and children perceived to be attractive or unattractive by those teachers. It was hypothesized that attractive children would exhibit more "positive,"…
Gaming Redefines Interactivity for Learning
ERIC Educational Resources Information Center
DeKanter, Nick
The new definition of interactivity has as its focal point the skills of people, not the capabilities of the technology. The goal is to enhance the interaction between people and the learning that can only occur among curious and motivated individuals working together. The social nature of people, the increasing capabilities of technology and the…
Distinguishing Ordinal and Disordinal Interactions
ERIC Educational Resources Information Center
Widaman, Keith F.; Helm, Jonathan L.; Castro-Schilo, Laura; Pluess, Michael; Stallings, Michael C.; Belsky, Jay
Re-parameterized regression models may enable tests of crucial theoretical predictions involving interactive effects of predictors that cannot be tested directly using standard approaches. First, we present a re-parameterized regression model for the Linear x Linear interaction of 2 quantitative predictors that yields point and interval estimates…
Sexual Interaction in Nonclinical Couples.
ERIC Educational Resources Information Center
Woody, Jane D.; D'Souza, Henry J.
Reports on the sexual functioning and interaction of 58 nonclinical heterosexual couples as measured by the Sexual Interaction System Scale (SISS). On all five SISS factors, the nonclinical sample scored significantly better than persons in therapy for sexual dysfunction; they also reported satisfactory relationship adjustment and high levels of…
The Wonders of Interactive Whiteboards
ERIC Educational Resources Information Center
Starkman, Neal
This article discusses the advantages of using interactive whiteboards in the classroom. Developed by Smart Technologies, the Smart Board is one of several interactive whiteboards on the market today. Through Smart Board, starters can write, erase, and perform mouse functions with their finger, a pen, or anything with a maneuverable, firm surface.…
Scattering calculations and confining interactions
NASA Technical Reports Server (NTRS)
Buck, Warren W.; Maung, Khin M.
Most of the research work performed under this grant were concerned with strong interaction processes ranging from kaon-nucleon interaction to proton-nucleus scattering calculations. Research performed under this grant can be categorized into three groups: (1) parametrization of fundamental interactions, (2) development of formal theory, and (3) calculations based upon the first two. Parametrizations of certain fundamental interactions, such as kaon-nucleon interaction, for example, were necessary because kaon-nucleon scattering amplitude was needed to perform kaon-nucleus scattering calculations. It was possible to calculate kaon-nucleon amplitudes from the first principle, but it was unnecessary for the purpose of the project. Similar work was also done for example for anti-protons and anti-nuclei. Formal developments to some extent were also pursued so that consistent calculations can be done.
Hyperfine interaction in hydrogenated graphene
NASA Astrophysics Data System (ADS)
Garcia, Noel; Melle, Manuel; Fernandez-Rossier, Joaquin
We study the hyperfine interaction of Hydrogen chemisorbed in graphene nanostructures with a gap in their spectrum, such as islands and ribbons. Chemisorption of Hydrogen on graphene results in a bound in-gap state that hosts a single electron localized around the adatom. Using both density functional theory and a four-orbital tight-binding model we study the hyperfine interaction between the hydrogen nuclear spin and the conduction electrons in graphene. We find that the strength of the hyperfine interaction decreases for larger nanostructures for which the energy gap is smaller. We then compare the results of the hyperfine interaction for large nanostructures with those of graphene 2D crystal with a periodic arrangement of chemisorbed Hydrogen atoms, obtaining very similar results. The magnitude of the hyperfine interaction is about 150 MHz, in line with that of Si:P. We acknowledge financial support by Marie-Curie-ITN 607904-SPINOGRAPH.
Noncovalent interaction of carbon nanostructures.
Umadevi, Deivasigamani; Panigrahi, Swati; Sastry, Garikapati Narahari
The potential application of carbon nanomaterials in biology and medicine increases the necessity to understand the nature of their interactions with living organisms and the environment. The primary forces of interaction at the nano-bio interface are mostly noncovalent in nature. Quantifying such interactions and identifying various factors that influence such interactions is a question of outstanding fundamental interest in academia and industry. In this Account, we have summarized our recent studies in understanding the noncovalent interactions of carbon nanostructures (CNSs), which were obtained by employing first-principles calculations on various model systems representing carbon nanotubes (CNTs) and graphene. Bestowed with an extended sp(2) carbon network, which is a common feature in all of these nanostructures, they exhibit π-π interactions with aromatic molecules (benzene, naphthalene, nucleobases, amino acids), cation-π type of interactions with metal ions, anion-π interactions with anions, and other XH···π type of interactions with various small molecules (H2O, NH3, CH4, H2, etc.). CNTs are wrapped-up forms of two-dimensional graphene, and hence, it is interesting to compare the binding abilities of these two allotropes that differ in their curvature. The chirality and curvature of CNSs appear to play a major role in determining the structural, energetic, and functional properties. Flat graphene shows stronger noncovalent interactions than the curved nanotubes toward various substrates. Understanding the interactions of CNSs with organic molecules and biomolecules has gained a great deal of research interest because of their potential applications in various fields. Aromatic hydrocarbons show a strong propensity to interact with CNSs via the π-π mode of interaction rather than CH···π interaction. As DNA sequencing appears to be one of the most important potential applications of carbon nanomaterials, the study of CNS
Final State Interactions Effects in Neutrino-Nucleus Interactions
Golan, Tomasz; Juszczak, Cezary; Sobczyk, Jan T.
Final State Interactions effects are discussed in the context of Monte Carlo simulations of neutrino-nucleus interactions. A role of Formation Time is explained and several models describing this effect are compared. Various observables which are sensitive to FSI effects are reviewed including pion-nucleus interaction and hadron yields in backward hemisphere. NuWro Monte Carlo neutrino event generator is described and its ability to understand neutral current $\\pi^0$ production data in $\\sim 1$ GeV neutrino flux experiments is demonstrated.
Nuclear Electric Dipole Moment of 3He
Stetcu, I; P.Liu, C; Friar, J L; Hayes, A C; Navratil, P
A permanent electric dipole moment (EDM) of a physical system would require time-reversal (T) violation, which is equivalent to charge-conjugation-parity (CP) violation by CPT invariance. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Nuclear EDMs can be studied at ion storage rings with sensitivities that may be competitive with atomic and neutron measurements. Here we calculate the magnitude of the CP-violating EDM of {sup 3}He and the expected sensitivity of such a measurement to the underlying CP-violating interactions. Assuming that the coupling constants are of comparable magnitude for {pi}-, {rho}-, and {omega}-exchanges, we find that the pion-exchange contribution dominates. Finally, our results suggest that a measurement of the {sup 3}He EDM is complementary to the planned neutron and deuteron experiments, and could provide a powerful constraint for the theoretical models of the pion-nucleon P,T-violating interaction.
The Experimental Investigation of the Missing N*- and Δ-RESONANCES Problem:. Current Status and Perspectives
NASA Astrophysics Data System (ADS)
Sumachev, V. V.; Bekrenev, V. S.; Beloglazov, Yu. A.; Filimonov, E. A.; Kovalev, A. I.; Kozlenko, N. G.; Kruglov, S. P.; Kulbardis, A. A.; Lopatin, I. V.; Novinsky, D. V.; Shchedrov, V. A.; Trautman, V. Yu.; Alekseev, I. G.; Budkovsky, P. E.; Kanavets, V. P.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Ryltsov, V. V.; Sulimov, A. D.; Svirida, D. N.; Bazhanov, N. A.; Bunyatova, E. I.
Numerous attempts to create a model that would exactly reproduce the N* - and Δ - resonances spectrum (that was presented in the Review of Particle Physics) failed. The existing models usually predicted considerably more resonances (twice or more in number) than were found in elastic πN - scattering. This problem is known as the problem of "missing" resonances. The recent partial wave analysis (PWA) SP06 that was made at George Washington University (2006) and included the modern experimental data revealed considerably fewer (approximately half) the N*- and Δ-resonances than those presented in the Review of Particle Physics (RPP) tables (2006). This disagreement invites further experimental investigation of the pion-nucleon interactions. Recent spin rotation parameter A and R measurements of the PNPI and PNPI-ITEP collaborations resolved a part of the twofold ambiguities of the PWA's. These results were used in the last PWA of the George Washington University (GWU) groups. The proposal for the additional measurements of the differential cross section and spin-rotation parameters R and A in the resonance region of the πN interactions is motivated. Such additional experiments are necessary to resolve the problem of the narrow (Γ < 30 MeV) baryon resonances existing and to complete monosemantic PWA of the πN elastic scattering.
Baryon mass splittings and strong violation in SU(3) chiral perturbation theory
de Vries, Jordy; Mereghetti, Emanuele; Walker-Loud, Andre P.
We study SU(3) flavor breaking corrections to the relation between the octet baryon masses and the nucleon-meson CP-violating interactions induced by the QCD theta term. We also work within the framework of SU(3) chiral perturbation theory and work through next-to-next-to-leading order in the SU(3) chiral expansion, which is O(m2q). At lowest order, the CP-odd couplings induced by the QCD θ- term are determined by mass splittings of the baryon octet, the classic result of Crewther et al. We show that for each isospin-invariant CP-violating nucleon-meson interaction there exists one relation which is respected by loop corrections up to the order we work, while other leading-order relations are violated. With these relations we extract a precise value of the pion-nucleon coupling g-0 by using recent lattice QCD evaluations of the proton-neutron mass splitting. Additionally, we derive semi-precise values for CP-violating coupling constants between heavier mesons and nucleons and discuss their phenomenological impact on electric dipole moments of nucleons and nuclei.
Baryon mass splittings and strong CP violation in SU(3) chiral perturbation theory
de Vries, Jordy; Mereghetti, Emanuele; Walker-Loud, Andre P.
We study SU(3) flavor breaking corrections to the relation between the octet baryon masses and the nucleon-meson CP-violating interactions induced by the QCD theta term. We also work within the framework of SU(3) chiral perturbation theory and work through next-to-next-to-leading order in the SU(3) chiral expansion, which is O(m2q). At lowest order, the CP-odd couplings induced by the QCD θ- term are determined by mass splittings of the baryon octet, the classic result of Crewther et al. We show that for each isospin-invariant CP-violating nucleon-meson interaction there exists one relation which is respected by loop corrections up to the ordermore » we work, while other leading-order relations are violated. With these relations we extract a precise value of the pion-nucleon coupling g-0 by using recent lattice QCD evaluations of the proton-neutron mass splitting. Additionally, we derive semi-precise values for CP-violating coupling constants between heavier mesons and nucleons and discuss their phenomenological impact on electric dipole moments of nucleons and nuclei.« less
Nuclear Electric Dipole Moment of ^{3}_He
Stetcu, I.; Liu, C.-P.; Friar, J. L.; Hayes, A. C.; Navratil, P.
A permanent electric dipole moment (EDM) of a physical system would require time-reversal (T) violation, which is equivalent to charge-conjugation-parity (CP) violation by CPT invariance. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Nuclear EDMs can be studied at ion storage rings with sensitivities that may be competitive with atomic and neutron measurements. Here we calculate the magnitude of the CP-violating EDM of ^{3}_He and the expected sensitivity of such a measurement to the underlyng CP-violating interactions. Assuming that the coupling constants are of comparable magnitude for {\\pi}-, {\\rho}-, and {\\omega}-exchanges, we find that the pion-exchange contribution dominates. Our results suggest that a measurement of the ^{3}_He EDM is complementary to the planned neutron and deuteron experiments, and could provide a powerful constraint for the theoretical models of the pion-nucleon P,T-violating interaction.
Magnetoencephalographic correlates of audiotactile interaction.
Lütkenhöner, B; Lammertmann, C; Simões, C; Hari, R
To seek for correlates of an interaction between auditory and somatosensory processing, the brain's magnetic field in response to simultaneously presented auditory (A) and tactile (T) stimuli was compared with the sum of the respective unimodal responses (A+T). The stimuli were binaural 1047-Hz tone bursts of 60 dB sensation level and tactile pressure pulses to the right thumb. The mean interval between two stimuli of the same modality was 1.95 s. The magnetic field was recorded using a 306-channel whole-scalp neuromagnetometer. A clear audiotactile interaction was revealed in the hemisphere contralateral to the side of tactile stimulation in six of eight subjects, whereas in the ipsilateral hemisphere an interaction was noticed in only three subjects. The time courses of these audiotactile interaction fields typically showed major deflections of opposite polarities around 140 and 220 ms. The first deflection appeared to arise in the region of the secondary somatosensory cortex (SII). The polarity of this interaction was consistent with the view that the auditory stimulus resulted in a partial inhibition in SII. In two subjects, strong indications of auditory contributions to the interaction were available, although in different hemispheres. The relatively high interindividual variability of the observed interaction, which represents potential neural substrates for multisensory integration, could indicate that the way subjects perceive the simultaneous presentation of auditory and tactile stimuli differs. PMID:11848694
Bacteriophage protein-protein interactions.
Häuser, Roman; Blasche, Sonja; Dokland, Terje; Haggård-Ljungquist, Elisabeth; von Brunn, Albrecht; Salas, Margarita; Casjens, Sherwood; Molineux, Ian; Uetz, Peter
Bacteriophages T7, λ, P22, and P2/P4 (from Escherichia coli), as well as ϕ29 (from Bacillus subtilis), are among the best-studied bacterial viruses. This chapter summarizes published protein interaction data of intraviral protein interactions, as well as known phage-host protein interactions of these phages retrieved from the literature. We also review the published results of comprehensive protein interaction analyses of Pneumococcus phages Dp-1 and Cp-1, as well as coliphages λ and T7. For example, the ≈55 proteins encoded by the T7 genome are connected by ≈43 interactions with another ≈15 between the phage and its host. The chapter compiles published interactions for the well-studied phages λ (33 intra-phage/22 phage-host), P22 (38/9), P2/P4 (14/3), and ϕ29 (20/2). We discuss whether different interaction patterns reflect different phage lifestyles or whether they may be artifacts of sampling. Phages that infect the same host can interact with different host target proteins, as exemplified by E. coli phage λ and T7. Despite decades of intensive investigation, only a fraction of these phage interactomes are known. Technical limitations and a lack of depth in many studies explain the gaps in our knowledge. Strategies to complete current interactome maps are described. Although limited space precludes detailed overviews of phage molecular biology, this compilation will allow future studies to put interaction data into the context of phage biology. PMID:22748812
Bacteriophage Protein–Protein Interactions
Häuser, Roman; Blasche, Sonja; Dokland, Terje; Haggård-Ljungquist, Elisabeth; von Brunn, Albrecht; Salas, Margarita; Casjens, Sherwood; Molineux, Ian
Bacteriophages T7, λ, P22, and P2/P4 (from Escherichia coli), as well as ϕ29 (from Bacillus subtilis), are among the best-studied bacterial viruses. This chapter summarizes published protein interaction data of intraviral protein interactions, as well as known phage–host protein interactions of these phages retrieved from the literature. We also review the published results of comprehensive protein interaction analyses of Pneumococcus phages Dp-1 and Cp-1, as well as coliphages λ and T7. For example, the ≈55 proteins encoded by the T7 genome are connected by ≈43 interactions with another ≈15 between the phage and its host. The chapter compiles published interactions for the well-studied phages λ (33 intra-phage/22 phage-host), P22 (38/9), P2/P4 (14/3), and ϕ29 (20/2). We discuss whether different interaction patterns reflect different phage lifestyles or whether they may be artifacts of sampling. Phages that infect the same host can interact with different host target proteins, as exemplified by E. coli phage λ and T7. Despite decades of intensive investigation, only a fraction of these phage interactomes are known. Technical limitations and a lack of depth in many studies explain the gaps in our knowledge. Strategies to complete current interactome maps are described. Although limited space precludes detailed overviews of phage molecular biology, this compilation will allow future studies to put interaction data into the context of phage biology. PMID:22748812
Hidden interaction in SBO galaxies
NASA Technical Reports Server (NTRS)
Galletta, G.; Bettoni, D.; Oosterloo, T.; Fasano, G.
Galaxies, like plants, show a large variety of grafts: an individual of some type connects physically with a neighborhood of same or different type. The effects of these interactions between galaxies have a broad range of morphologies depending, among other quantities, on the distance of the closest approach between systems and the relative size of the two galaxies. A sketch of the possible situations is shown in tabular form. This botanical classification is just indicative, because the effects of interactions can be notable also at relatively large separations, when additional conditions are met, as for example low density of the interacting systems or the presence of intra-cluster gas. In spite of the large variety of encounters and effects, in the literature the same terms are often used to refer to different types of interactions. Analysis indicates that only few of the situations show evident signs of interaction. They appear to be most relevant when the size of the two galaxies is comparable. Bridges and tails, like the well known case of NGC 4038/39, the Antennae, are only observed for a very low percentage of all galaxies (approx. 0.38 percent, Arp and Madore 1977). In most cases of gravitational bond between two galaxies, the effects of interactions are not relevant or evident. For instance, the detection of stellar shells (Malin and Carter 1983), which have been attributed to the accretion of gas stripped from another galaxy or to the capture and disruption of a small stellar system (Quinn 1984), requires particular observing and reduction techniques. Besides these difficulties of detection, time plays an important role in erasing, within a massive galaxy, the effects of interactions with smaller objects. This can happen on a timescale shorter than the Hubble time, so the number of systems now showing signs of interaction suggests lower limits to the true frequency of interactions in the life-time of a stellar system.
Pion-Skyrmion scattering: collective coordinates at work
Peskin, M.E.
It is argued that the Skryme model, and more generally, the picture of the nucleon as a chiral soliton, can give a qualitatively correct picture of pion-nucleon scattering, considering both group-theoretic and more scheme-dependent results. The properties of the nucleon and its excited states in large-N quantum chromodynamics are discussed qualitatively. Then the pion-nucleon S-matrix is reduced. It is found that the model succeeds at the first level of calculation in producing many of the features of pion-nucleon scattering which are revealed by experiment, but that many aspects of the description need to be better understood, including the treatment of nonleading corrections near threshold and the inclusion of inelastic channels. 22 refs., 8 figs. (LEW)
Measuring protein interactions by microchip self-interaction chromatography.
García, Carlos D; Hadley, DeGail J; Wilson, W William; Henry, Charles S
The self-interaction of proteins is of paramount importance in aggregation and crystallization phenomena. Solution conditions leading to a change in the state of aggregation of a protein, whether amorphous or crystalline, have mainly been discovered by the use of trial and error screening of large numbers of solutions. Self-interaction chromatography has the potential to provide a quantitative method for determination of protein self-interactions amenable to high-throughput screening. This paper describes the construction and characterization of a microchip separation system for low-pressure self-interaction chromatography using lysozyme as a model protein. The retention time was analyzed as a function of mobile-phase composition, amount of protein injected, flow rate, and stationary-phase modification. The capacity factors (k') as a function of crystallizing agent concentration are compared with previously published values for the osmotic second virial coefficient (B(22)) obtained by static light scattering, showing the ability of the chip to accurately determine protein-protein interactions. A 500-fold reduction in protein consumption and the possibility of using conventional instrumentation and automation are some of the advantages over currently used methodologies for evaluating protein-protein interactions. PMID:12790668
Generalized interactions supported on hypersurfaces
NASA Astrophysics Data System (ADS)
Exner, Pavel; Rohleder, Jonathan
We analyze a family of singular Schrödinger operators with local singular interactions supported by a hypersurface Σ ⊂ ℝn, n ≥ 2, being the boundary of a Lipschitz domain, bounded or unbounded, not necessarily connected. At each point of Σ the interaction is characterized by four real parameters, the earlier studied case of δ- and δ'-interactions being particular cases. We discuss spectral properties of these operators and derive operator inequalities between those referring to the same hypersurface but different couplings and describe their implications for spectral properties.
Aligned interactions in cosmic rays
NASA Astrophysics Data System (ADS)
Kempa, J.
The first clean Centauro was found in cosmic rays years many ago at Mt Chacaltaya experiment. Since that time, many people have tried to find this type of interaction, both in cosmic rays and at accelerators. But no one has found a clean cases of this type of interaction.It happened finally in the last exposure of emulsion at Mt Chacaltaya where the second clean Centauro has been found. The experimental data for both the Centauros and STRANA will be presented and discussed in this paper. We also present our comments to the intriguing question of the existence of a type of nuclear interactions at high energy with alignment.
Aligned interactions in cosmic rays
Kempa, J.
The first clean Centauro was found in cosmic rays years many ago at Mt Chacaltaya experiment. Since that time, many people have tried to find this type of interaction, both in cosmic rays and at accelerators. But no one has found a clean cases of this type of interaction.It happened finally in the last exposure of emulsion at Mt Chacaltaya where the second clean Centauro has been found. The experimental data for both the Centauros and STRANA will be presented and discussed in this paper. We also present our comments to the intriguing question of the existence of a type of nuclear interactions at high energy with alignment.
Research in interactive scene analysis
NASA Technical Reports Server (NTRS)
Tenenbaum, J. M.; Barrow, H. G.; Weyl, S. A.
Cooperative (man-machine) scene analysis techniques were developed whereby humans can provide a computer with guidance when completely automated processing is infeasible. An interactive approach promises significant near-term payoffs in analyzing various types of high volume satellite imagery, as well as vehicle-based imagery used in robot planetary exploration. This report summarizes the work accomplished over the duration of the project and describes in detail three major accomplishments: (1) the interactive design of texture classifiers; (2) a new approach for integrating the segmentation and interpretation phases of scene analysis; and (3) the application of interactive scene analysis techniques to cartography.
Interactive explorations of hierarchical segmentations
NASA Technical Reports Server (NTRS)
Tilton, James C.
The authors report on the implementation of an interactive tool, called HSEGEXP, to interactively explore the hierarchical segmentation produced by the iterative parallel region growing (IPRG) algorithm to select the best segmentation result. This combination of the HSEGEXP tool with the IPRG algorithm amounts to a computer-assisted image segmentation system guided by human interaction. The initial application of the HSEGEXP tool is in the refinement of ground reference data based on the IPRG/HSEGEXP segmentation of the corresponding remotely sensed image data. The HSEGEXP tool is being used to help evaluate the effectiveness of an automatic 'best' segmentation process under development.
Creep-Fatigue Interaction Testing
NASA Technical Reports Server (NTRS)
Halford, Gary R.
Fatigue fives in metals are nominally time independent below 0.5 T(sub Melt). At higher temperatures, fatigue lives are altered due to time-dependent, thermally activated creep. Conversely, creep rates are altered by super. imposed fatigue loading. Creep and fatigue generally interact synergistically to reduce material lifetime. Their interaction, therefore, is of importance to structural durability of high-temperature structures such as nuclear reactors, reusable rocket engines, gas turbine engines, terrestrial steam turbines, pressure vessel and piping components, casting dies, molds for plastics, and pollution control devices. Safety and lifecycle costs force designers to quantify these interactions. Analytical and experimental approaches to creep-fatigue began in the era following World War II. In this article experimental and life prediction approaches are reviewed for assessing creep-fatigue interactions of metallic materials. Mechanistic models are also discussed briefly.
Weak interactions and presupernova evolution
Aufderheide, M.B. State Univ. of New York . Dept. of Physics)
The role of weak interactions, particularly electron capture and {beta}{sup {minus}} decay, in presupernova evolution is discussed. The present uncertainty in these rates is examined and the possibility of improving the situation is addressed. 12 refs., 4 figs.
The InterAction Database includes demographic and prescription information for more than 500,000 patients in the northern and middle Netherlands and has been integrated with other systems to enhance data collection and analysis.
Mediated Character of Economic Interactions
NASA Astrophysics Data System (ADS)
Stepanic, Josip; Bertovic, Igor; Kasac, Josip
Economic interactions are conducted between economic agents - individuals and collectives, through exchange of natural or artificial entities - goods, services and money, in a myriad of combinations. In this article we adopt a microscopic point of view, concentrate on the exchanged entities, and extract their relevant attributes as seen from structurally simple economic processes. Following that, we approach the interpretation of the economic interactions with their mediated character emphasized. Mediators of the interaction are locally available environment units. They are locally recognized and appropriately interpreted in a given value set as goods and money. The overall intensity of economic interactions considered is related to mediators' spatial and temporal characteristics. Extracted characteristics of mediators and economic processes are compacted in the set of formal rules. The approach is connected with similar approaches in economy and physics.
Examining Classroom Interactions & Mathematical Discourses
ERIC Educational Resources Information Center
Grant, Melva R.
This investigation examined interactions in three classrooms to determine how they influenced Discourses related to mathematics learning and teaching. Mathematics education literature suggests that effective mathematics instruction includes mathematical Discourses. However, effective mathematical Discourses within mathematics classrooms vary…
Standards and procedures for INTERACT
Bonnet, J.M.
There is presented a checklist of items that writers of execute procedures should consider when developing procedures for public use or exchange among INTERACT user sites. An example using the checklist is also given. 4 figures.
Shell Scores with Interactive Video.
ERIC Educational Resources Information Center
Zemke, Ron
Documents Shell Oil's success with interactive video training (IVT) and identifies the costs involved in this long-term investment. Provides guidelines for judging the effectiveness of IVT programs. (SK)
Universal Description of Interactive Growth
NASA Astrophysics Data System (ADS)
Condat, Carlos; Barberis, Lucas
Although the existence of organism-organism interactions during ontogenesis is well documented, ontogenetic growth models usually focus exclusively on the organism-environment interaction. We develop a new formalism to describe the interactive growth of two or more organisms in a given environment. Using a vector formulation of the Phenomenological Universalities concept, we are able to characterize the joint growth of two or more interacting organisms and assess the direct mutual influences between them, as well as the indirect influences that operate through environment modifications. The resulting equations describe synergetic, antagonistic, and cooperative growth, and can be applied to biological and ecological problems. As an example, we examine the growth dynamics in a mixed-species plantation. This work was supported by ANPCyT and CONICET (Argentina).
Examples of Dietary Supplement Interactions
... the risk of bruising and bleeding. Supplement: Goldenseal Root Possible drug-supplement interaction with: Cyclosporine. Can decrease ... using the liver's cytochrome P450 enzyme system. Goldenseal root may decrease how quickly the liver breaks down ...
Particle interactions in microemulsion systems
Brouwer, W.M.; Nieuwenhuis, E.A.; Kops-Werkhoven, M.M.
This study obtains information about the type of interactions between microemulsion particles as a function of their composition using time averaged and dynamic light scattering and sedimentation measurements and checks the consistency of the experimental data with respect to the generalized Einstein relation. Interactions between microemulsion particles are affected by the flexibility of the soap chains. The more flexible the soap chains, the lesser the attraction forces between the particles. The lack of consistency in the interaction behavior as obtained from different experimental techniques is an important observation, which leads to the conclusion that care should be taken in the determination of the interaction behavior in microemulsion systems from one or 2 experimental techniques. 24 referernces.
Spacecraft Environmental Interactions Technology, 1983
NASA Technical Reports Server (NTRS)
State of the art of environment interactions dealing with low-Earth-orbit plasmas; high-voltage systems; spacecraft charging; materials effects; and direction of future programs are contained in over 50 papers.
Multipurpose interactive NASA information system
NASA Technical Reports Server (NTRS)
Hill, J. M.; Keefer, R. L.; Sanders, D. R.; Seitz, R. N.
Multipurpose Interactive NASA Information System (MINIS) is data management system capable of retrieving descriptive data from LANDSAT photos. General enough to be used with other user-defined data bases, interactive data management and information retrieval system was especially developed for small and medium-sized computers. It uses free-form data base that allows one to create entirely new and different data bases and to control format of output products.
Fujisawa, Kaori; Humbert-Droz, Marie; Letrun, Romain; Vauthey, Eric; Wesolowski, Tomasz A; Sakai, Naomi; Matile, Stefan
We report that anion-π and cation-π interactions can occur on the same aromatic surface. Interactions of this type are referred to as ion pair-π interactions. Their existence, nature, and significance are elaborated in the context of spectral tuning, ion binding in solution, and activation of cell-penetrating peptides. The origin of spectral tuning by ion pair-π interactions is unraveled with energy-minimized excited-state structures: The solvent- and pH-independent red shift of absorption and emission of push-pull fluorophores originates from antiparallel ion pair-π attraction to their polarized excited state. In contrast, the complementary parallel ion pair-π repulsion is spectroscopically irrelevant, in part because of charge neutralization by intriguing proton and electron transfers on excited push-pull surfaces. With time-resolved fluorescence measurements, very important differences between antiparallel and parallel ion pair-π interactions are identified and quantitatively dissected from interference by aggregation and ion pair dissociation. Contributions from hydrogen bonding, proton transfer, π-π interactions, chromophore twisting, ion pairing, and self-assembly are systematically addressed and eliminated by concise structural modifications. Ion-exchange studies in solution, activation of cell-penetrating peptides in vesicles, and computational analysis all imply that the situation in the ground state is complementary to spectral tuning in the excited state; i.e., parallel rather than antiparallel ion pair-π interactions are preferred, despite repulsion from the push-pull dipole. The overall quite complete picture of ion pair-π interactions provided by these remarkably coherent yet complex results is expected to attract attention throughout the multiple disciplines of chemistry involved. PMID:26291550
Future of Neutrino Interaction Models
NASA Astrophysics Data System (ADS)
Terri, Ryan
Neutrino-nucleus cross sections are one of the dominant sources of systematic errors in long-baseline neutrino oscillation experiments. To achieve the goals of precision measurements of the mixing angles and difference of the mass eigenstates squared, and discover the mass hierarchy and CP-violating phase, the underlying neutrino interactions must be better understood. This poster will mention some recent improvements in models in the interaction generators as well as some possible future improvements for proposed experiments.
Dynamic interactions in neural networks
Arbib, M.A. ); Amari, S. )
The study of neural networks is enjoying a great renaissance, both in computational neuroscience, the development of information processing models of living brains, and in neural computing, the use of neurally inspired concepts in the construction of intelligent machines. This volume presents models and data on the dynamic interactions occurring in the brain, and exhibits the dynamic interactions between research in computational neuroscience and in neural computing. The authors present current research, future trends and open problems.
Biological interactions at metal surfaces
NASA Astrophysics Data System (ADS)
Hansen, Douglas C.
Adsorption of biomolecules, whether it is a consequence of a material being put into service in a biological medium such as a biomedical implant device or a heat exchanger tube, are governed by fundamental interactions and surface conditions that are well characterized (and in some cases not so well). This work reviews those fundamental interactions and also describes a study of the adsorption of a naturally occurring biological polymer onto a stainless steel alloy.
On transonic viscous inviscid interaction
NASA Astrophysics Data System (ADS)
Buldakov, E. V.; Ruban, A. I.
The paper is concerned with the interaction between the boundary layer on a smooth body surface and the outer inviscid compressible flow in the vicinity of a sonic point. First, a family of local self-similar solutions of the Kármán Guderley equation describing the inviscid flow behaviour immediately outside the interaction region is analysed; one of them was found to be suitable for describing the boundary-layer separation. In this solution the pressure has a singularity at the sonic point with the pressure gradient on the body surface being inversely proportional to the cubic root dpw/dx [similar] ([minus sign]x)[minus sign]1/3 of the distance ([minus sign]x) from the sonic point. This pressure gradient causes the boundary layer to interact with the inviscid part of the flow. It is interesting that the skin friction in the boundary layer upstream of the interaction region shows a characteristic logarithmic decay which determines an unusual behaviour of the flow inside the interaction region. This region has a conventional triple-deck structure. To study the interactive flow one has to solve simultaneously the Prandtl boundary-layer equations in the lower deck which occupies a thin viscous sublayer near the body surface and the Kármán Guderley equations for the upper deck situated in the inviscid flow outside the boundary layer. In this paper a numerical solution of the interaction problem is constructed for the case when the separation region is entirely contained within the viscous sublayer and the inviscid part of the flow remains marginally supersonic. The solution proves to be non-unique, revealing a hysteresis character of the flow in the interaction region.
Natural interaction for unmanned systems
NASA Astrophysics Data System (ADS)
Taylor, Glenn; Purman, Ben; Schermerhorn, Paul; Garcia-Sampedro, Guillermo; Lanting, Matt; Quist, Michael; Kawatsu, Chris
Military unmanned systems today are typically controlled by two methods: tele-operation or menu-based, search-andclick interfaces. Both approaches require the operator's constant vigilance: tele-operation requires constant input to drive the vehicle inch by inch; a menu-based interface requires eyes on the screen in order to search through alternatives and select the right menu item. In both cases, operators spend most of their time and attention driving and minding the unmanned systems rather than on being a warfighter. With these approaches, the platform and interface become more of a burden than a benefit. The availability of inexpensive sensor systems in products such as Microsoft Kinect™ or Nintendo Wii™ has resulted in new ways of interacting with computing systems, but new sensors alone are not enough. Developing useful and usable human-system interfaces requires understanding users and interaction in context: not just what new sensors afford in terms of interaction, but how users want to interact with these systems, for what purpose, and how sensors might enable those interactions. Additionally, the system needs to reliably make sense of the user's inputs in context, translate that interpretation into commands for the unmanned system, and give feedback to the user. In this paper, we describe an example natural interface for unmanned systems, called the Smart Interaction Device (SID), which enables natural two-way interaction with unmanned systems including the use of speech, sketch, and gestures. We present a few example applications SID to different types of unmanned systems and different kinds of interactions.
Warfarin interactions with medicinal herbs.
Milić, Natasa; Milosević, Natasa; Golocorbin Kon, Svetlana; Bozić, Teodora; Abenavoli, Ludovico; Borrelli, Francesca
Recognition of the adverse effects of medicinal herbs is not routine and the reports on such effects are even less frequent in clinical practice. Potential herb-drug interactions are of a major safety concern, especially for drugs with narrow therapeutic indices like warfarin, which can lead to severe adverse reactions that are sometimes life-threatening. The interactions between warfarin and medicinal herbs described in the literature have been summarized in this paper relying on Medline database (via PubMed) using the key words: warfarin, herbal supplements and interactions. The references on the analyzed literature have been investigated in order to collect the existing data. The case reports with severe adverse effects such as spontaneous postoperative bleeding, formation of hematomas, hematemesis, melena, thrombosis, subarachnoid hemorrhage and/or subdural hematomas after concomitant use of warfarin and the medicinal herbs: Panax ginseng, Hypericum perforatum, Salvia milthiorizza, Gingko biloba, Serenoa repens, Angelica sinensis, Vaccinium species, Allium sativum, Zingiber officinale, Tanacetum parthenium, Lucium barbarum, Matricaria chamomilla, Boswellia serrata and Camellia sinensis have been estimated. Some of the interactions between warfarin and medicinal herbs have been well assessed proving that they are closely-dependent. The interactions between warfarin and medicinal herbs, not generally reported in previous reviews, are presented in our review. The health professionals who are involved in treating the patients are expected to be fully informed about the interactions between warfarin and medicinal herbs in order to minimize the health risks of the patients. PMID:25233607
Interactions of amelogenin with phospholipids.
Lokappa, Sowmya Bekshe; Chandrababu, Karthik Balakrishna; Dutta, Kaushik; Perovic, Iva; Evans, John Spencer; Moradian-Oldak, Janet
Amelogenin protein has the potential to interact with other enamel matrix proteins, mineral, and cell surfaces. We investigated the interactions of recombinant amelogenin rP172 with small unilamellar vesicles as model membranes, toward the goal of understanding the mechanisms of amelogenin-cell interactions during amelogenesis. Dynamic light scattering (DLS), fluorescence spectroscopy, circular dichroism (CD), and nuclear magnetic resonance (NMR) were used. In the presence of phospholipid vesicles, a blue shift in the Trp fluorescence emission maxima of rP172 was observed (∼334 nm) and the Trp residues of rP172 were inaccessible to the aqueous quencher acrylamide. DLS studies indicated complexation of rP172 and phospholipids, although the possibility of fusion of phospholipids following amelogenin addition cannot be ruled out. NMR and CD studies revealed a disorder-order transition of rP172 in a model membrane environment. Strong fluorescence resonance energy transfer from Trp in rP172 to DNS-bound-phospholipid was observed, and fluorescence polarization studies indicated that rP172 interacted with the hydrophobic core region of model membranes. Our data suggest that amelogenin has ability to interact with phospholipids and that such interactions may play key roles in enamel biomineralization as well as reported amelogenin signaling activities. PMID:25298002
Interactions of Amelogenin with Phospholipids
Lokappa, Sowmya Bekshe; Chandrababu, Karthik Balakrishna; Dutta, Kaushik; Perovic, Iva; Evans, John Spencer; Moradian-Oldak, Janet
Amelogenin protein has the potential to interact with other enamel matrix proteins, mineral and cell surfaces. We investigated the interactions of recombinant amelogenin rP172 with small unilamellar vesicles as model membranes, towards the goal of understanding the mechanisms of amelogenin-cell interactions during amelogenesis. Dynamic light scattering (DLS), fluorescence spectroscopy, circular dichroism (CD) and nuclear magnetic resonance (NMR) were used. In the presence of phospholipid vesicles, a blue shift in the Trp fluorescence emission maxima of rP172 was observed (~334 nm) and the Trp residues of rP172 were inaccessible to the aqueous quencher acrylamide. Though in DLS studies we cannot exclude the possibility of fusion of liposomes as the result of amelogenin addition, NMR and CD studies revealed a disorder-order transition of rP172 in a model membrane environment. Strong FRET from Trp in rP172 to DNS–bound-phospholipid was observed, and fluorescence polarization studies indicated that rP172 interacted with the hydrophobic core region of model membranes. Our data suggest that amelogenin has ability to interact with phospholipids and that such interactions may play key roles in enamel biomineralization as well as reported amelogenin signaling activities. PMID:25298002
Technology Adoption: an Interaction Perspective
NASA Astrophysics Data System (ADS)
Sitorus, Hotna M.; Govindaraju, Rajesri; Wiratmadja, I. I.; Sudirman, Iman
The success of a new technology depends on how well it is accepted by its intended users. Many technologies face the problem of low adoption rate, despite the benefits. An understanding of what makes people accept or reject a new technology can help speed up the adoption rate. This paper presents a framework for technology adoption based on an interactive perspective, resulting from a literature study on technology adoption. In studying technology adoption, it is necessary to consider the interactions among elements involved in the system, for these interactions may generate new characteristics or new relationships. The interactions among elements in a system adoption have not received sufficient consideration in previous studies of technology adoption. Based on the proposed interaction perspective, technology adoption is elaborated by examining interactions among the individual (i.e. the user or prospective user), the technology, the task and the environment. The framework is formulated by adopting several theories, including Perceived Characteristics of Innovating, Diffusion of Innovation Theory, Technology Acceptance Model, Task-Technology Fit and usability theory. The proposed framework is illustrated in the context of mobile banking adoption. It is aimed to offer a better understanding of determinants of technology adoption in various contexts, including technology in manufacturing systems.
Measurement of interaction between antiprotons
NASA Astrophysics Data System (ADS)
The Star Collaboration; Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Bairathi, V.; Banerjee, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de La Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Cervantes, M. C.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; de Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Klein, S.; Kochenda, L.; Koetke, D. D.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, Z. M.; Li, Y.; Li, W.; Li, X.; Li, C.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, R.; Ma, Y. G.; Ma, L.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; Meehan, K.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Peterson, A.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, M. K.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, Z.; Sun, X. M.; Sun, Y.; Sun, X.; Surrow, B.; Svirida, N.; Szelezniak, M. A.; Tang, Z.; Tang, A. H.; Tarnowsky, T.; Tawfik, A.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, H.; Wang, J. S.; Wang, Y.; Wang, Y.; Wang, F.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z. G.; Xie, W.; Xin, K.; Xu, Y. F.; Xu, Q. H.; Xu, H.; Xu, N.; Xu, Z.; Yang, Y.; Yang, C.; Yang, S.; Yang, Y.; Yang, Q.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, J. B.; Zhang, Z.; Zhang, J.; Zhang, S.; Zhang, X. P.; Zhang, J.; Zhang, Y.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.
One of the primary goals of nuclear physics is to understand the force between nucleons, which is a necessary step for understanding the structure of nuclei and how nuclei interact with each other. Rutherford discovered the atomic nucleus in 1911, and the large body of knowledge about the nuclear force that has since been acquired was derived from studies made on nucleons or nuclei. Although antinuclei up to antihelium-4 have been discovered and their masses measured, little is known directly about the nuclear force between antinucleons. Here, we study antiproton pair correlations among data collected by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC), where gold ions are collided with a centre-of-mass energy of 200 gigaelectronvolts per nucleon pair. Antiprotons are abundantly produced in such collisions, thus making it feasible to study details of the antiproton-antiproton interaction. By applying a technique similar to Hanbury Brown and Twiss intensity interferometry, we show that the force between two antiprotons is attractive. In addition, we report two key parameters that characterize the corresponding strong interaction: the scattering length and the effective range of the interaction. Our measured parameters are consistent within errors with the corresponding values for proton-proton interactions. Our results provide direct information on the interaction between two antiprotons, one of the simplest systems of antinucleons, and so are fundamental to understanding the structure of more-complex antinuclei and their properties.
Measurement of interaction between antiprotons.
One of the primary goals of nuclear physics is to understand the force between nucleons, which is a necessary step for understanding the structure of nuclei and how nuclei interact with each other. Rutherford discovered the atomic nucleus in 1911, and the large body of knowledge about the nuclear force that has since been acquired was derived from studies made on nucleons or nuclei. Although antinuclei up to antihelium-4 have been discovered and their masses measured, little is known directly about the nuclear force between antinucleons. Here, we study antiproton pair correlations among data collected by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC), where gold ions are collided with a centre-of-mass energy of 200 gigaelectronvolts per nucleon pair. Antiprotons are abundantly produced in such collisions, thus making it feasible to study details of the antiproton-antiproton interaction. By applying a technique similar to Hanbury Brown and Twiss intensity interferometry, we show that the force between two antiprotons is attractive. In addition, we report two key parameters that characterize the corresponding strong interaction: the scattering length and the effective range of the interaction. Our measured parameters are consistent within errors with the corresponding values for proton-proton interactions. Our results provide direct information on the interaction between two antiprotons, one of the simplest systems of antinucleons, and so are fundamental to understanding the structure of more-complex antinuclei and their properties. PMID:26536116
A Taxonomy of Interaction for Instructional Multimedia.
ERIC Educational Resources Information Center
Schwier, Richard A.
This paper rejects the hardware-based "levels of interaction" made popular in interactive video literature to describe human-machine interaction in favor of a new taxonomy of learner-media interaction based on the type of cognitive engagement experienced by learners. Interaction can be described on three levels, based on the quality of the…
Stand By for Fun: Experience and Interaction.
ERIC Educational Resources Information Center
Crockford, Douglas
This paper explores interactivity, and considers what should be done to create a mass market for interactive media. It is suggested that one way to do so is to examine the video game phenomenon, and a model of interactivity is proposed. The model, a "home interactive theater," would involve interaction in the telling of a story, with the…
Environmental interactions in space exploration: Environmental interactions working group
NASA Technical Reports Server (NTRS)
Kolecki, Joseph C.; Hillard, G. Barry
With the advent of the Space Exploration Initiative, the possibility of designing and using systems on scales heretofore unattempted presents exciting new challenges in systems design and space science. The environments addressed by the Space Exploration Initiative include the surfaces of the Moon and Mars, as well as the varied plasma and field environments which will be encountered by humans and cargo enroute to these destinations. Systems designers will need to understand environmental interactions and be able to model these mechanisms from the earliest conceptual design stages through design completion. To the end of understanding environmental interactions and establishing robotic precursor mission requirements, an Environmental Interactions Working Group was established as part of the Robotic Missions Working Group. The working group is described, and its current activities are updated.
Systematics of the Extraction of the Elementary γn -->π- p Reaction Cross Sections beyond the Impulse Approximation for γd -->π- pp
NASA Astrophysics Data System (ADS)
Berroteran, Oliver; Strakovsky, Igor
The radiative decay width of neutral baryons may be extracted from π- and π0 photo-production off the neutron, involving a bound neutron target, requiring the use of model-dependent nuclear final state interaction (FSI) corrections. The cross section for the processes γn -->π- p will be extracted from recent CLAS (E = 400 - 2500 MeV) and MAX-lab (E = 146 - 166 MeV) measurements for γd -->π- pp accounting for Fermi motion effects in the Impulse Approximation (IA) as well as nucleon-nucleon- and pion-nucleon-FSI effects beyond the IA. To test the GW-ITEP FSI code for γn -->π- p in a reliable way to obtain information on systematics of the extraction of the elementary γn -->π- p reaction cross sections beyond the IA for γd -->π- pp, three key factors were chosen and analyzed: (i) The sensitivity to the number of steps of integration for numerical calculations of the five-fold integrals in the determination of FSI amplitudes; (ii) The sensitivity to the alternative deuteron-wave functions. (iii) The sensitivity to the experimental kinematic cut-off of the detected protons (the experimental information is uncertain). Preliminary estimations show that the contribution of all three factors to the overall systematics is less than 4%. U.S. DOE, Office of Science, Office of Nuclear Physics, Grant DE-FG02-99-ER41110.
Measuring the nucleon strangeness and related matrix elements using lattice QCD
NASA Astrophysics Data System (ADS)
Freeman, Walter
We calculate the strange quark content of the nucleon using a novel method with the MILC lattice QCD gauge ensembles. The strangeness of the nucleon is related to the interaction cross section between dark matter and ordinary nuclear matter e.g. in detectors) in many models. Previous results for this quantity suffered from uncontrolled systematic errors and/or large statistical uncertainties. The first result using our methods was the first modern calculation of the strangeness of the nucleon with good control of systematic errors and reasonably small statistical errors, greatly reducing the uncertainty in dark matter detection cross sections. A refinement of this method allows for further reduction of statistical error. On the MILC Asqtad data, we obtain
Pion scattering and nuclear dynamics
Johnson, M.B.
A phenomenological optical-model analysis of pion elastic scattering and single- and double-charge-exchange scattering to isobaric-analog states is reviewed. Interpretation of the optical-model parameters is briefly discussed, and several applications and extensions are considered. The applications include the study of various nuclear properties, including neutron deformation and surface-fluctuation contributions to the density. One promising extension for the near future would be to develop a microscopic approach based on powerful momentum-space methods brought to existence over the last decade. In this, the lowest-order optical potential as well as specific higher-order pieces would be worked out in terms of microscopic pion-nucleon and delta-nucleon interactions that can be determined within modern meson-theoretical frameworks. A second extension, of a more phenomenological nature, would use coupled-channel methods and shell-model wave functions to study dynamical nuclear correlations in pion double charge exchange. 35 refs., 11 figs., 1 tab.
Two-Pion Exchange Nucleon-Nucleon Potential: Relativistic Chiral Expansion
R. Higa; M.R. Robilotta
We present a relativistic procedure for the chiral expansion of the two-pion exchange component of the NN potential, which emphasizes the role of intermediate pi N subamplitudes. The relationship between power counting in pi N and NN processes is discussed and results are expressed directly in terms of observable subthreshold coefficients. Interactions are determined by one and two-loop diagrams, involving pions, nucleons and other degrees of freedom, frozen into empirical subthreshold coefficients. The full evaluation of these diagrams produces amplitudes containing many different loop integrals. Their simplification by means of relations among these integrals leads to a set of intermediate results. Subsequent truncation to order(q{sup 4}) yields the relativistic potential, which depends on four loop integrals, representing bubble, triangle, crossed box and box diagrams. The bubble and triangle integrals are the same as in pi N scattering and we have shown that they also determine the chiral structures of box and crossed box integrals. Relativistic threshold effects were found to begin to contribute at order(q{sup 5}) only and our results should coincide with those of the standard heavy baryon approach. Checking this explicitly, we found differences due to the Goldberger-Treiman discrepancy and terms of order(q{sup 3}), possibly associated with the iteration of the OPEP.
The OZI rule: A unique selector of glueballs and hadron spectroscopy
Lindenbaum, S.J. City Coll., New York, NY )
In the first part of this talk I have reviewed the history of the OZI rule. I then have shown how it is a unique selector glueballs and new quarks in hadron spectroscopy. In particular the only glueball candidates which cannot be explained by other hypotheses within QCD are the I{sup G}J{sup PC} = 0{sup +}2{sup ++} g{sub T}(2010), g{sub T},(2300) and g{sub T{double prime}}(2340) observed in the OZI suppressed reaction {pi}{sup {minus}} p {yields} {phi}{phi}n. The narrowness of the J/{psi} and T can only be explained by OZI suppression. I then reminisced about the 1954 Rochester Conference in which our work on {pi}{sup {plus minus}}p total cross sections and {pi}{sup {plus minus}} production combined gave convincing evidence for the delta being the first resonance. Described how the 1964 Dubna Conference results on small angle {pi}{sup {plus minus}}p elastic scattering led to the first critical experimental check of the pion-nucleon forward dispersion relations which showed that the basic axions of modern field theory worked on strong interactions at high energies. I finally reminisced about glueballs in the 1982 and 1988 Rochester Conferences. 52 refs., 17 figs., 3 tabs.
New analysis of the low-energy π±p differential cross-sections of the CHAOS Collaboration
NASA Astrophysics Data System (ADS)
Matsinos, E.; Rasche, G.
In a previous paper, we reported the results of a partial-wave analysis (PWA) of the pion-nucleon (πN) differential cross-sections (DCSs) of the CHAOS Collaboration and came to the conclusion that the angular distribution of their π+p data sets is incompatible with the rest of the modern (meson factory) database. The present work, re-addressing this issue, has been instigated by a number of recent improvements in our analysis, namely regarding the inclusion of the theoretical uncertainties when investigating the reproduction of experimental data sets on the basis of a given "theoretical" solution, modifications in the parametrization of the form factors of the proton and of the pion entering the electromagnetic part of the πN amplitude, and the inclusion of the effects of the variation of the σ-meson mass when fitting the ETH model of the πN interaction to the experimental data. The new analysis of the CHAOS DCSs confirms our earlier conclusions and casts doubt on the value for the πN Σ term, which Stahov, Clement and Wagner have extracted from these data.
Chiral perturbation theory with nucleons
Meissner, U.G.
I review the constraints posed on the interactions of pions, nucleons and photons by the spontaneously broken chiral symmetry of QCD. The framework to perform these calculations, chiral perturbation theory, is briefly discussed in the meson sector. The method is a simultaneous expansion of the Greens functions in powers of external moments and quark masses around the massless case, the chiral limit. To perform this expansion, use is made of a phenomenological Lagrangian which encodes the Ward-identities and pertinent symmetries of QCD. The concept of chiral power counting is introduced. The main part of the lectures of consists in describing how to include baryons (nucleons) and how the chiral structure is modified by the fact that the nucleon mass in the chiral limit does not vanish. Particular emphasis is put on working out applications to show the strengths and limitations of the methods. Some processes which are discussed are threshold photopion production, low-energy compton scattering off nucleons, {pi}N scattering and the {sigma}-term. The implications of the broken chiral symmetry on the nuclear forces are briefly described. An alternative approach, in which the baryons are treated as very heavy fields, is touched upon.
Electron Photon Interaction Cross Sections
Version 00 The Electron Photon Interaction Cross Sections, EPICS, provides the atomic data needed to perform coupled Electron-Photon transport calculations, to produce accurate macroscopic results, such as energy deposit and dose. Atomic data is provided for elements, Z = 1 to 100, over the energy range 10 eV to 100 GeV; note that nuclear data, such as photo-nuclear, and data for compounds, are not included. All data is in a simple computer independent text formatmore » that is standard and presented to a high precision that can be easily read by computer codes written in any computer language, e.g., C, C++, and FORTRAN. EPICS includes four separate data bases that are designed to be used in combination, these include, The Evaluated Electron Data Library (EEDL), to describe the interaction of electrons with matter. The Evaluated Photon Data Library (EPDL), to describe the interaction of photons with matter. The Evaluated Atomic Data Library (EADL), to describe the emission of electrons and photons back to neutrality following an ionizing event, caused by either electron or photon interactions. The Evaluated Excitation Data Library (EXDL), to describe the excitation of atoms due to photon interaction. All of these are available in the Extended ENDL format (ENDLX) in which the evaluations were originally performed. The first three are also available in the ENDF format; as yet ENDF does not include formats to handle excitation data (EXDL).« less
Drug interactions and the statins
Herman, R J
Drug interactions commonly occur in patients receiving treatment with multiple medications. Most interactions remain unrecognized because drugs, in general, have a wide margin of safety or because the extent of change in drug levels is small when compared with the variation normally seen in clinical therapy. All drug interactions have a pharmacokinetic or pharmacodynamic basis and are predictable given an understanding of the pharmacology of the drugs involved. Drugs most liable to pose problems are those having concentration-dependent toxicity within, or close to, the therapeutic range; those with steep dose-response curves; those having high first-pass metabolism or those with a single, inhibitable route of elimination. Knowing which drugs possess these intrinsic characteristics, together with a knowledge of hepatic P-450 metabolism and common enzyme-inducing and enzyme-inhibiting drugs, can greatly assist physicians in predicting interactions that may be clinically relevant. This article reviews the pharmacology of drug interactions that can occur with hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) to illustrate the scope of the problem and the ways in which physicians may manage this important therapeutic class of drugs. PMID:10584091
Information capacity of specific interactions.
Huntley, Miriam H; Murugan, Arvind; Brenner, Michael P
Specific interactions are a hallmark feature of self-assembly and signal-processing systems in both synthetic and biological settings. Specificity between components may arise from a wide variety of physical and chemical mechanisms in diverse contexts, from DNA hybridization to shape-sensitive depletion interactions. Despite this diversity, all systems that rely on interaction specificity operate under the constraint that increasing the number of distinct components inevitably increases off-target binding. Here we introduce "capacity," the maximal information encodable using specific interactions, to compare specificity across diverse experimental systems and to compute how specificity changes with physical parameters. Using this framework, we find that "shape" coding of interactions has higher capacity than chemical ("color") coding because the strength of off-target binding is strongly sublinear in binding-site size for shapes while being linear for colors. We also find that different specificity mechanisms, such as shape and color, can be combined in a synergistic manner, giving a capacity greater than the sum of the parts. PMID:27155013
Electron Photon Interaction Cross Sections
Cullen, D. E.
Version 00 The Electron Photon Interaction Cross Sections, EPICS, provides the atomic data needed to perform coupled Electron-Photon transport calculations, to produce accurate macroscopic results, such as energy deposit and dose. Atomic data is provided for elements, Z = 1 to 100, over the energy range 10 eV to 100 GeV; note that nuclear data, such as photo-nuclear, and data for compounds, are not included. All data is in a simple computer independent text format that is standard and presented to a high precision that can be easily read by computer codes written in any computer language, e.g., C, C++, and FORTRAN. EPICS includes four separate data bases that are designed to be used in combination, these include, The Evaluated Electron Data Library (EEDL), to describe the interaction of electrons with matter. The Evaluated Photon Data Library (EPDL), to describe the interaction of photons with matter. The Evaluated Atomic Data Library (EADL), to describe the emission of electrons and photons back to neutrality following an ionizing event, caused by either electron or photon interactions. The Evaluated Excitation Data Library (EXDL), to describe the excitation of atoms due to photon interaction. All of these are available in the Extended ENDL format (ENDLX) in which the evaluations were originally performed. The first three are also available in the ENDF format; as yet ENDF does not include formats to handle excitation data (EXDL).
Soft particles with anisotropic interactions
NASA Astrophysics Data System (ADS)
Schurtenberger, Peter
Responsive colloids such as thermo- or pH-sensitive microgels are ideal model systems to investigate the relationship between the nature of interparticle interactions and the plethora of self-assembled structures that can form in colloidal suspensions. They allow for a variation of the form, strength and range of the interaction potential almost at will. While microgels have extensively been used as model systems to investigate various condensed matter problems such as glass formation, jamming or crystallization, they can also be used to study systems with anisotropic interactions. Here we show results from a systematic investigation of the influence of softness and anisotropy on the structural and dynamic properties of strongly interacting suspensions. We focus first on ionic microgels. Due to their large number of internal counterions they possess very large polarisabilities, and we can thus use external electrical ac fields to generate large dipolar contributions to the interparticle interaction potential. This leads to a number of new crystal phases, and we can trigger crystal-crystal phase transitions through the appropriate choice of the field strength. We then show that this approach can be extended to more complex particle shapes in an attempt to copy nature's well documented success in fabricating complex nanostructures such as virus shells via self assembly. European Research Council (ERC-339678-COMPASS).
Hayes, J S; Czekanska, E M; Richards, R G
The realm of surface-dependent cell and tissue responses is the foundation of orthopaedic-device-related research. However, to design materials that elicit specific responses from tissues is a complex proposition mainly because the vast majority of the biological principles controlling the interaction of cells with implants remain largely ambiguous. Nevertheless, many surface properties, such as chemistry and topography, can be manipulated in an effort to selectively control the cell-material interaction. On the basis of this information there has been much research in this area, including studies focusing on the structure and composition of the implant interface, optimization of biological and chemical coatings and elucidation of the mechanisms involved in the subsequent cell-material interactions. Although a wealth of information has emerged, it also advocates the complexity and dynamism of the cell-material interaction. Therefore, this chapter aims to provide the reader with an introduction to the basic concepts of the cell-material interaction and to provide an insight into the factors involved in determining the cell and tissue response to specific surface features, with specific emphasis on surface microtopography. PMID:21984613
Motor interference in interactive contexts.
Chinellato, Eris; Castiello, Umberto; Sartori, Luisa
Action observation and execution share overlapping neural substrates, so that simultaneous activation by observation and execution modulates motor performance. Previous literature on simple prehension tasks has revealed that motor influence can be two-sided: facilitation for observed and performed congruent actions and interference for incongruent actions. But little is known of the specific modulations of motor performance in complex forms of interaction. Is it possible that the very same observed movement can lead either to interference or facilitation effects on a temporally overlapping congruent executed action, depending on the context? To answer this question participants were asked to perform a reach-to-grasp movement adopting a precision grip (PG) while: (i) observing a fixation cross, (ii) observing an actor performing a PG with interactive purposes, (iii) observing an actor performing a PG without interactive purposes. In particular, in the interactive condition the actor was shown trying to pour some sugar on a large cup located out of her reach but close to the participant watching the video, thus eliciting in reaction a complementary whole-hand grasp. Notably, fine-grained kinematic analysis for this condition revealed a specific delay in the grasping and reaching components and an increased trajectory deviation despite the observed and executed movement's congruency. Moreover, early peaks of trajectory deviation seem to indicate that socially relevant stimuli are acknowledged by the motor system very early. These data suggest that interactive contexts can determine a prompt modulation of stimulus-response compatibility effects. PMID:26113835
Metal complex interactions with DNA.
Pages, Benjamin J; Ang, Dale L; Wright, Elisé P; Aldrich-Wright, Janice R
Increasing numbers of DNA structures are being revealed using biophysical, spectroscopic and genomic methods. The diversity of transition metal complexes is also growing, as the unique contributions that transition metals bring to the overall structure of metal complexes depend on the various coordination numbers, geometries, physiologically relevant redox potentials, as well as kinetic and thermodynamic characteristics. The vast range of ligands that can be utilised must also be considered. Given this diversity, a variety of biological interactions is not unexpected. Specifically, interactions with negatively-charged DNA can arise due to covalent/coordinate or subtle non-coordinate interactions such as electrostatic attraction, groove binding and intercalation as well as combinations of all of these modes. The potential of metal complexes as therapeutic agents is but one aspect of their utility. Complexes, both new and old, are currently being utilised in conjunction with spectroscopic and biological techniques to probe the interactions of DNA and its many structural forms. Here we present a review of metal complex-DNA interactions in which several binding modes and DNA structural forms are explored. PMID:25427534
Composite strongly interacting dark matter
NASA Astrophysics Data System (ADS)
Cline, James M.; Liu, Zuowei; Moore, Guy D.; Xue, Wei
It has been suggested that cold dark matter (CDM) has difficulties in explaining tentative evidence for noncuspy halo profiles in small galaxies, and the low velocity dispersions observed in the largest Milky Way satellites ("too-big-to-fail" problem). Strongly self-interacting dark matter has been noted as a robust solution to these problems. The elastic cross sections required are much larger than predicted by generic CDM models, but could naturally be of the right size if dark matter is composite. We explore in a general way the constraints on models where strongly interacting CDM is in the form of dark "atoms" or "molecules," or bound states of a confining gauge interaction ("hadrons"). These constraints include considerations of relic density, direct detection, big bang nucleosynthesis, the cosmic microwave background, and LHC data.
Bacterial Communities: Interactions to Scale.
Stubbendieck, Reed M; Vargas-Bautista, Carol; Straight, Paul D
In the environment, bacteria live in complex multispecies communities. These communities span in scale from small, multicellular aggregates to billions or trillions of cells within the gastrointestinal tract of animals. The dynamics of bacterial communities are determined by pairwise interactions that occur between different species in the community. Though interactions occur between a few cells at a time, the outcomes of these interchanges have ramifications that ripple through many orders of magnitude, and ultimately affect the macroscopic world including the health of host organisms. In this review we cover how bacterial competition influences the structures of bacterial communities. We also emphasize methods and insights garnered from culture-dependent pairwise interaction studies, metagenomic analyses, and modeling experiments. Finally, we argue that the integration of multiple approaches will be instrumental to future understanding of the underlying dynamics of bacterial communities. PMID:27551280
The nitrogen cycle: Atmosphere interactions
NASA Technical Reports Server (NTRS)
Levine, J. S.
Atmospheric interactions involving the nitrogen species are varied and complex. These interactions include photochemical reactions, initiated by the absorption of solar photons and chemical kinetic reactions, which involve both homogeneous (gas-to-gas reactions) and heterogeneous (gas-to-particle) reactions. Another important atmospheric interaction is the production of nitrogen oxides by atmospheric lightning. The nitrogen cycle strongly couples the biosphere and atmosphere. Many nitrogen species are produced by biogenic processes. Once in the atmosphere nitrogen oxides are photochemically and chemically transformed to nitrates, which are returned to the biosphere via precipitation, dry deposition and aerosols to close the biosphere-atmosphere nitrogen cycle. The sources, sinks and photochemistry/chemistry of the nitrogen species; atmospheric nitrogen species; souces and sinks of nitrous oxide; sources; sinks and photochemistry/chemistry of ammonia; seasonal variation of the vertical distribution of ammonia in the troposphere; surface and atmospheric sources of the nitrogen species, and seasonal variation of ground level ammonia are summarized.
Hairpin Vortices: Autogeneration and Interaction
NASA Astrophysics Data System (ADS)
Sabatino, Daniel; Maharjan, Rijan; Sanders, Andrew
The regeneration of hairpin vortices is examined in a free-surface water channel where vortices are artificially generated by means of injection in a laminar boundary layer. The process is visualized with dye and hydrogen bubble-wire techniques. The strength of an isolated hairpin required to begin the autogeneration process is established by means of PIV measurements on the symmetry plane. Because hairpins are in close proximity in a fully-turbulent boundary layer, two hairpins are generated at different streamwise locations and allowed to interact at different stages of development. The relative position, strength and maturity of the interacting hairpins that generate secondary vortices are examined. The morphology of the generation process and of the resulting secondary hairpin for both the isolated and interacting cases are discussed and compared to previous work. Supported by the National Science Foundation under Grant CBET-1040236.
Interaction of two swimming Paramecia.
Ishikawa, Takuji; Hota, Masateru
The interaction between two swimming Paramecium caudatum was investigated experimentally. Cell motion was restricted between flat plates, and avoiding and escape reactions were observed, as well as hydrodynamic interactions. The results showed that changes in direction between two swimming cells were induced mainly by hydrodynamic forces and that the biological reaction was a minor factor. Numerical simulations were also performed using a boundary element method. P. caudatum was modelled as a rigid spheroid with surface tangential velocity measured by a particle image velocimetry (PIV) technique. Hydrodynamic interactions observed in the experiment agreed well with the numerical simulations, so we can conclude that the present cell model is appropriate for describing the motion of P. caudatum. PMID:17079716
Hadronization processes in neutrino interactions
NASA Astrophysics Data System (ADS)
Katori, Teppei; Mandalia, Shivesh
Next generation neutrino oscillation experiments utilize details of hadronic final states to improve the precision of neutrino interaction measurements. The hadronic system was often neglected or poorly modelled in the past, but they have significant effects on high precision neutrino oscillation and cross-section measurements. Among the physics of hadronic systems in neutrino interactions, the hadronization model controls multiplicities and kinematics of final state hadrons from the primary interaction vertex. For relatively high invariant mass events, many neutrino experiments rely on the PYTHIA program. Here, we show a possible improvement of this process in neutrino event generators, by utilizing expertise from the HERMES experiment. Finally, we estimate the impact on the systematics of hadronization models for neutrino mass hierarchy analysis using atmospheric neutrinos such as the PINGU experiment.
Elastocapillary interactions on nematic films
Liu, Iris B.; Gharbi, Mohamed A.; Ngo, Victor L.; Kamien, Randall D.; Yang, Shu; Stebe, Kathleen J.
Rod-like colloids distort fluid interfaces and interact by capillarity. We explore this interaction at the free surface of aligned nematic liquid crystal films. Naive comparison of capillary and elastic energies suggests that particle assembly would be determined solely by surface tension. Here, we demonstrate that, under certain circumstances, the capillary and elastic effects are complementary and each plays an important role. Particles assemble end-to-end, as dictated by capillarity, and align along the easy axis of the director field, as dictated by elasticity. On curved fluid interfaces, however, curvature capillary energies can overcome the elastic orientations and drive particle migration along curvature gradients. Domains of dominant interaction and their transition are investigated. PMID:25941380
Temporal Interactions between Cortical Rhythms
Roopun, Anita K.; Kramer, Mark A.; Carracedo, Lucy M.; Kaiser, Marcus; Davies, Ceri H.; Traub, Roger D.; Kopell, Nancy J.; Whittington, Miles A.
Multiple local neuronal circuits support different, discrete frequencies of network rhythm in neocortex. Relationships between different frequencies correspond to mechanisms designed to minimise interference, couple activity via stable phase interactions, and control the amplitude of one frequency relative to the phase of another. These mechanisms are proposed to form a framework for spectral information processing. Individual local circuits can also transform their frequency through changes in intrinsic neuronal properties and interactions with other oscillating microcircuits. Here we discuss a frequency transformation in which activity in two co-active local circuits may combine sequentially to generate a third frequency whose period is the concatenation sum of the original two. With such an interaction, the intrinsic periodicity in each component local circuit is preserved – alternate, single periods of each original rhythm form one period of a new frequency – suggesting a robust mechanism for combining information processed on multiple concurrent spatiotemporal scales. PMID:19225587
Sonic boom interaction with turbulence
NASA Technical Reports Server (NTRS)
Rusak, Zvi; Giddings, Thomas E.
A recently developed transonic small-disturbance model is used to analyze the interactions of random disturbances with a weak shock. The model equation has an extended form of the classic small-disturbance equation for unsteady transonic aerodynamics. It shows that diffraction effects, nonlinear steepening effects, focusing and caustic effects and random induced vorticity fluctuations interact simultaneously to determine the development of the shock wave in space and time and the pressure field behind it. A finite-difference algorithm to solve the mixed-type elliptic hyperbolic flows around the shock wave is presented. Numerical calculations of shock wave interactions with various deterministic vorticity and temperature disturbances result in complicate shock wave structures and describe peaked as well as rounded pressure signatures behind the shock front, as were recorded in experiments of sonic booms running through atmospheric turbulence.
Stacking interactions and DNA intercalation
Li, Dr. Shen; Cooper, Valentino R; Thonhauser, Prof. Timo; Lundqvist, Prof. Bengt I.; Langreth, David C.
The relationship between stacking interactions and the intercalation of proflavine and ellipticine within DNA is investigated using a nonempirical van der Waals density functional for the correlation energy. Our results, employing a binary stack model, highlight fundamental, qualitative differences between base-pair base-pair interactions and that of the stacked intercalator base pair system. Most notable result is the paucity of torque which so distinctively defines the Twist of DNA. Surprisingly, this model, when combined with a constraint on the twist of the surrounding base-pair steps to match the observed unwinding of the sugar-phosphate backbone, was sufficient for explaining the experimentally observed proflavine intercalator configuration. Our extensive mapping of the potential energy surface of base-pair intercalator interactions can provide valuable information for future nonempirical studies of DNA intercalation dynamics.
Interactive autonomy and robotic skills
NASA Technical Reports Server (NTRS)
Kellner, A.; Maediger, B.
Current concepts of robot-supported operations for space laboratories (payload servicing, inspection, repair, and ORU exchange) are mainly based on the concept of 'interactive autonomy' which implies autonomous behavior of the robot according to predefined timelines, predefined sequences of elementary robot operations and within predefined world models supplying geometrical and other information for parameter instantiation on the one hand, and the ability to override and change the predefined course of activities by human intervention on the other hand. Although in principle a very powerful and useful concept, in practice the confinement of the robot to the abstract world models and predefined activities appears to reduce the robot's stability within real world uncertainties and its applicability to non-predefined parts of the world, calling for frequent corrective interaction by the operator, which in itself may be tedious and time-consuming. Methods are presented to improve this situation by incorporating 'robotic skills' into the concept of interactive autonomy.
Interactive robots in experimental biology.
Krause, Jens; Winfield, Alan F T; Deneubourg, Jean-Louis
Interactive robots have the potential to revolutionise the study of social behaviour because they provide several methodological advances. In interactions with live animals, the behaviour of robots can be standardised, morphology and behaviour can be decoupled (so that different morphologies and behavioural strategies can be combined), behaviour can be manipulated in complex interaction sequences and models of behaviour can be embodied by the robot and thereby be tested. Furthermore, robots can be used as demonstrators in experiments on social learning. As we discuss here, the opportunities that robots create for new experimental approaches have far-reaching consequences for research in fields such as mate choice, cooperation, social learning, personality studies and collective behaviour. PMID:21496942
Studies of food drug interactions.
Aman, Syed Faisal; Hassan, Fouzia; Naqvi, Baqar S; Hasan, Syed Muhammmad Farid
Medicines can treat and alleviate many diseases provided that they must be taken properly to ensure that they are safe and useful. One issue related with the medicines is that whether to take on empty stomach or with food. The present work gives information regarding food-drug interactions that were studied by collecting seventy five prescriptions from various hospitals. In most of the collected prescriptions, food-drug interactions were detected using the literature available. It was also found that only few studies have been carried out so far on the effect of food on drug disposition in the Asian population. Thus more studies on food-drug interactions particularly in the local population is recommended in order to determine the effect of food and food components on drug disposition and to the kinetics of the drugs which has not yet well highlighted in this part of the world. PMID:20566446
Bacterial Communities: Interactions to Scale
Stubbendieck, Reed M.; Vargas-Bautista, Carol; Straight, Paul D.
In the environment, bacteria live in complex multispecies communities. These communities span in scale from small, multicellular aggregates to billions or trillions of cells within the gastrointestinal tract of animals. The dynamics of bacterial communities are determined by pairwise interactions that occur between different species in the community. Though interactions occur between a few cells at a time, the outcomes of these interchanges have ramifications that ripple through many orders of magnitude, and ultimately affect the macroscopic world including the health of host organisms. In this review we cover how bacterial competition influences the structures of bacterial communities. We also emphasize methods and insights garnered from culture-dependent pairwise interaction studies, metagenomic analyses, and modeling experiments. Finally, we argue that the integration of multiple approaches will be instrumental to future understanding of the underlying dynamics of bacterial communities. PMID:27551280
Hadronization processes in neutrino interactions
Katori, Teppei; Mandalia, Shivesh
Next generation neutrino oscillation experiments utilize details of hadronic final states to improve the precision of neutrino interaction measurements. The hadronic system was often neglected or poorly modelled in the past, but they have significant effects on high precision neutrino oscillation and cross-section measurements. Among the physics of hadronic systems in neutrino interactions, the hadronization model controls multiplicities and kinematics of final state hadrons from the primary interaction vertex. For relatively high invariant mass events, many neutrino experiments rely on the PYTHIA program. Here, we show a possible improvement of this process in neutrino event generators, by utilizing expertise from the HERMES experiment. Finally, we estimate the impact on the systematics of hadronization models for neutrino mass hierarchy analysis using atmospheric neutrinos such as the PINGU experiment.
Participant Interaction in Asynchronous Learning Environments: Evaluating Interaction Analysis Methods
ERIC Educational Resources Information Center
Blanchette, Judith
The purpose of this empirical study was to determine the extent to which three different objective analytical methods--sequence analysis, surface cohesion analysis, and lexical cohesion analysis--can most accurately identify specific characteristics of online interaction. Statistically significant differences were found in all points of…
The Volume Field Model about Strong Interaction and Weak Interaction
NASA Astrophysics Data System (ADS)
Liu, Rongwu
For a long time researchers have believed that strong interaction and weak interaction are realized by exchanging intermediate particles. This article proposes a new mechanism as follows: Volume field is a form of material existence in plane space, it takes volume-changing motion in the form of non-continuous motion, volume fields have strong interaction or weak interaction between them by overlapping their volume fields. Based on these concepts, this article further proposes a ``bag model'' of volume field for atomic nucleus, which includes three sub-models of the complex structure of fundamental body (such as quark), the atom-like structure of hadron, and the molecule-like structure of atomic nucleus. This article also proposes a plane space model and formulates a physics model of volume field in the plane space, as well as a model of space-time conversion. The model of space-time conversion suggests that: Point space-time and plane space-time convert each other by means of merging and rupture respectively, the essence of space-time conversion is the mutual transformations of matter and energy respectively; the process of collision of high energy hadrons, the formation of black hole, and the Big Bang of universe are three kinds of space-time conversions.
Interactional Feedback in Naturalistic Interaction between L2 English Learners
ERIC Educational Resources Information Center
Ranaweera, Mahishi
Theoretical and empirical data support that the feedback given in small group activities promote second language acquisition. There are many studies that have examined the impact of interaction on second language acquisition in controlled language situations. This study examines the small group activity "conversation partner" in order to…
Michigan molecular interactions r2: from interacting proteins to pathways.
Tarcea, V Glenn; Weymouth, Terry; Ade, Alex; Bookvich, Aaron; Gao, Jing; Mahavisno, Vasudeva; Wright, Zach; Chapman, Adriane; Jayapandian, Magesh; Ozgür, Arzucan; Tian, Yuanyuan; Cavalcoli, Jim; Mirel, Barbara; Patel, Jignesh; Radev, Dragomir; Athey, Brian; States, David; Jagadish, H V
Molecular interaction data exists in a number of repositories, each with its own data format, molecule identifier and information coverage. Michigan molecular interactions (MiMI) assists scientists searching through this profusion of molecular interaction data. The original release of MiMI gathered data from well-known protein interaction databases, and deep merged this information while keeping track of provenance. Based on the feedback received from users, MiMI has been completely redesigned. This article describes the resulting MiMI Release 2 (MiMIr2). New functionality includes extension from proteins to genes and to pathways; identification of highlighted sentences in source publications; seamless two-way linkage with Cytoscape; query facilities based on MeSH/GO terms and other concepts; approximate graph matching to find relevant pathways; support for querying in bulk; and a user focus-group driven interface design. MiMI is part of the NIH's; National Center for Integrative Biomedical Informatics (NCIBI) and is publicly available at: http://mimi.ncibi.org. PMID:18978014
An interactional approach to conceptualising small talk in medical interactions
Hudak, Pamela L.; Maynard, Douglas W.
In medical interactions, it may seem straightforward to identify 'small talk' as casual or social talk superfluous to the institutional work of dealing with patients' medical concerns. Such a broad characterisation is, however, extremely difficult to apply to actual talk, and more specificity is necessary to pursue analyses of how small talk is produced and what it achieves for participants in medical interactions. We offer an approach to delineating a subgenre of small talk called topicalised small talk (TST), derived on the basis of conversation analytically-informed analyses of routine consultations involving orthopaedic surgeons and older patients. TST is a line of talk that is referentially independent from their institutional identities as patients or surgeons, oriented instead to an aspect of the personal biography of one (or both), or to some neutral topic available to interactants in any setting (e.g. weather). Importantly, TST is an achievement of both patient and surgeon in that generation and pursuit of topic is mutually accomplished. In an exploratory but systematic analysis, when this approach was applied to a purposive sample of surgeon-patient interactions, TST was much more prevalent in visits with White than African American patients. Accounts for possible ethnic differences in TST are suggested. PMID:21545445
Entanglement interaction and the phase diagram of strongly interacting matter
NASA Astrophysics Data System (ADS)
Shao, G. Y.; Tang, Z. D.; Di Toro, M.; Colonna, M.; Gao, X. Y.; Gao, N.; Zhao, Y. L.
The entanglement interactions between the Polyakov loop and chiral condensate have been recently studied in the entangled Polyakov-loop Nambu-Jona-Lasinio model (EPNJL). The calculation shows that such an interaction plays an important role in the pseudocritical temperatures of deconfinement and chiral symmetry restoration. As a further study, here we construct a hadron-quark two-equation-of-state (two-EoS) model, based on the Walecka-quantum hadrodynamics and the EPNJL pictures, in order to study the equilibrium transition between hadronic and quark matter in heavy-ion collisions at finite densities and temperatures. We can explore the phase diagram of strongly interacting matter and the transition boundaries from nuclear to quark matter. We discuss the influence of the entanglement interaction on the critical point of the expected first-order phase transition in the two-EoS model. In particular, for charge asymmetric matter, we analyze the local asymmetry of the u , d quarks as a function of quark concentration in the hadron-quark mixed phase during the phase transition. We finally propose some related observables that are possibly measurable in heavy-ion collision experiments.
Pseudohaptic interaction with knot diagrams
NASA Astrophysics Data System (ADS)
Weng, Jianguang; Zhang, Hui
To make progress in understanding knot theory, we need to interact with the projected representations of mathematical knots, which are continuous in three dimensions (3-D) but significantly interrupted in the projective images. One way to achieve such a goal is to design an interactive system that allows us to sketch two-dimensional (2-D) knot diagrams by taking advantage of a collision-sensing controller and explore their underlying smooth structures through a continuous motion. Recent advances of interaction techniques have been made that allow progress in this direction. Pseudohaptics that simulate haptic effects using pure visual feedback can be used to develop such an interactive system. We outline one such pseudohaptic knot diagram interface. Our interface derives from the familiar pencil-and-paper process of drawing 2-D knot diagrams and provides haptic-like sensations to facilitate the creation and exploration of knot diagrams. A centerpiece of the interaction model simulates a physically reactive mouse cursor, which is exploited to resolve the apparent conflict between the continuous structure of the actual smooth knot and the visual discontinuities in the knot diagram representation. Another value in exploiting pseudohaptics is that an acceleration (or deceleration) of the mouse cursor (or surface locator) can be used to indicate the slope of the curve (or surface) of which the projective image is being explored. By exploiting these additional visual cues, we proceed to a full-featured extension to a pseudohaptic four-dimensional (4-D) visualization system that simulates the continuous navigation on 4-D objects and allows us to sense the bumps and holes in the fourth dimension. Preliminary tests of the software show that main features of the interface overcome some expected perceptual limitations in our interaction with 2-D knot diagrams of 3-D knots and 3-D projective images of 4-D mathematical objects.
Topology of molecular interaction networks.
Winterbach, Wynand; Van Mieghem, Piet; Reinders, Marcel; Wang, Huijuan; de Ridder, Dick
Molecular interactions are often represented as network models which have become the common language of many areas of biology. Graphs serve as convenient mathematical representations of network models and have themselves become objects of study. Their topology has been intensively researched over the last decade after evidence was found that they share underlying design principles with many other types of networks.Initial studies suggested that molecular interaction network topology is related to biological function and evolution. However, further whole-network analyses did not lead to a unified view on what this relation may look like, with conclusions highly dependent on the type of molecular interactions considered and the metrics used to study them. It is unclear whether global network topology drives function, as suggested by some researchers, or whether it is simply a byproduct of evolution or even an artefact of representing complex molecular interaction networks as graphs.Nevertheless, network biology has progressed significantly over the last years. We review the literature, focusing on two major developments. First, realizing that molecular interaction networks can be naturally decomposed into subsystems (such as modules and pathways), topology is increasingly studied locally rather than globally. Second, there is a move from a descriptive approach to a predictive one: rather than correlating biological network topology to generic properties such as robustness, it is used to predict specific functions or phenotypes.Taken together, this change in focus from globally descriptive to locally predictive points to new avenues of research. In particular, multi-scale approaches are developments promising to drive the study of molecular interaction networks further. PMID:24041013
Topology of molecular interaction networks
Molecular interactions are often represented as network models which have become the common language of many areas of biology. Graphs serve as convenient mathematical representations of network models and have themselves become objects of study. Their topology has been intensively researched over the last decade after evidence was found that they share underlying design principles with many other types of networks. Initial studies suggested that molecular interaction network topology is related to biological function and evolution. However, further whole-network analyses did not lead to a unified view on what this relation may look like, with conclusions highly dependent on the type of molecular interactions considered and the metrics used to study them. It is unclear whether global network topology drives function, as suggested by some researchers, or whether it is simply a byproduct of evolution or even an artefact of representing complex molecular interaction networks as graphs. Nevertheless, network biology has progressed significantly over the last years. We review the literature, focusing on two major developments. First, realizing that molecular interaction networks can be naturally decomposed into subsystems (such as modules and pathways), topology is increasingly studied locally rather than globally. Second, there is a move from a descriptive approach to a predictive one: rather than correlating biological network topology to generic properties such as robustness, it is used to predict specific functions or phenotypes. Taken together, this change in focus from globally descriptive to locally predictive points to new avenues of research. In particular, multi-scale approaches are developments promising to drive the study of molecular interaction networks further. PMID:24041013
[Drug interactions with contraceptive methods].
Simon, P; Hakkou, F; Warot, D
3 possible types of drug interactions with contraceptives involve oral contraceptives (OCs), IUDs, and spermicides. The interaction of combined OCs with various drugs is frequently discussed in the literature, but the reported facts are sometimes contradictory. Case studies have indicated failure of OCs in patients taking ampicillin, but comparative studies using ampicillin and placebos have shown no difference in rates of estrogen, progestogens, follicle stimulating hormone, or luteinizing hormone in the 2 groups. Individual differences and predispositions among some women appear to play a role in drug interactions. The clinician should be wary of modifying accepted prescription practices too readily in the face of findings that may be explained by other as yet undisclosed factors. Interactions are difficult to establish, as are their mechanisms. They may perhaps be explained by the estrogen or progestogen components of the pills, the timing of the antibiotic dose, the duration of treatment and the dosage used, resistance of the intestinal flora, self-medication, or other factors. The drug troleandomycin is a special case; it appears to favor the already existing tendency of OCs to provoke cholestatic jaundice. A table of drug interactions with OCs can be divided into 2 parts, those that have been confirmed and whose mechanisms of action are known, including antiepileptics such as phenobarbital, butobarbital, phenytoin, and primidone, and the drug rifampicin, which are enzyme inductors; and those that are suspected but as yet unconfirmed and whose mechanism of action is not established. The unconfirmed interactions involve a variety of effects in addition to pregnancy. It is not yet established whether enzyme inductors are a greater problem for users of low-dose pills, but the probable existence of individual variations in sensitivity causes problems in setting recommendations applicable to all patients. Interactions between progestogen-only OCs and other drugs
Dynamical Interactions Among Extrasolar Planets
NASA Astrophysics Data System (ADS)
Laughlin, G.
For certain multiple planet systems such as GJ 876 and 55 Cancri, which have (1) been observed for a large number of orbital periods, and which (2) have strong planet-planet gravitational interactions, the approximation that the planets are orbiting on independent Keplerian ellipses is inadequate. We discuss the production of self-consistent dynamical fits to these interacting systems, in which a minimization scheme (such as the Levenberg-Marquardt technique, or a Genetic Algorithm) is used to repeatedly drive an N-body integrator and improve the agreement between the integrated reflex motion of the central star and the observed radial velocities.
Cosmology and the weak interaction
Schramm, D.N. ):)
The weak interaction plays a critical role in modern Big Bang cosmology. This review will emphasize two of its most publicized cosmological connections: Big Bang nucleosynthesis and Dark Matter. The first of these is connected to the cosmological prediction of Neutrino Flavours, N{sub {nu}} {approximately} 3 which is now being confirmed at SLC and LEP. The second is interrelated to the whole problem of galaxy and structure formation in the universe. This review will demonstrate the role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure. 87 refs., 3 figs., 5 tabs.
Orbital, Rotational, and Climatic Interactions
NASA Technical Reports Server (NTRS)
Bills, Bruce G. (Editor)
The report of an international meeting on the topic of Orbital, Rotational, and Climatic Interactions, which was held 9-11 Jul. 1991 at the Johns Hopkins University is presented. The meeting was attended by 22 researchers working on various aspects of orbital and rotational dynamics, paleoclimate data analysis and modeling, solid-Earth deformation studies, and paleomagnetic analyses. The primary objective of the workshop was to arrive at a better understanding of the interactions between the orbital, rotational, and climatic variations of the Earth. This report contains a brief introduction and 14 contributed papers which cover most of the topics discussed at the meeting.
Elementary Particles and Weak Interactions
DOE R&D Accomplishments Database
Lee, T. D.; Yang, C. N.
Some general patterns of interactions between various elementary particles are reviewed and some general questions concerning the symmetry properties of these particles are studied. Topics are included on the theta-tau puzzle, experimental limits on the validity of parity conservation, some general discussions on the consequences due to possible non-invariance under P, C, and T, various possible experimental tests on invariance under P, C, and T, a two-component theory of the neutrino, a possible law of conservation of leptons and the universal Fermi interactions, and time reversal invariance and Mach's principle. (M.H.R.)
Exaggerated Claims for Interactive Stories
NASA Astrophysics Data System (ADS)
Thue, David; Bulitko, Vadim; Spetch, Marcia; Webb, Michael
As advertising becomes more crucial to video games' success, developers risk promoting their products beyond the features that they can actually include. For features of interactive storytelling, the effects of making such exaggerations are not well known, as reports from industry have been anecdotal at best. In this paper, we explore the effects of making exaggerated claims for interactive stories, in the context of the theory of advertising. Results from a human user study show that female players find linear and branching stories to be significantly less enjoyable when they are advertised with exaggerated claims.
Cosmology and the weak interaction
NASA Technical Reports Server (NTRS)
Schramm, David N.
The weak interaction plays a critical role in modern Big Bang cosmology. Two of its most publicized comological connections are emphasized: big bang nucleosynthesis and dark matter. The first of these is connected to the cosmological prediction of neutrine flavors, N(sub nu) is approximately 3 which in now being confirmed. The second is interrelated to the whole problem of galacty and structure formation in the universe. The role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure is demonstrated.
Radiative interactions in nonequilibrium flows
NASA Technical Reports Server (NTRS)
Tiwari, S. N.; Chandrasekhar, R.
The influence of vibrational and chemical nonequilibrium upon infrared radiative energy transfer in nonisothermal gases is investigated. Essential information is provided on rate equations, relaxation times, transfer equations, band absorption, and radiative flux equations. The methodology developed is applied to three specific cases. These are, absorbing-emitting species between isothermal parallel plates, radiating gases in the earth's atmosphere, and supersonic flow of premixed hydrogen and air in an expanding nozzle. The results obtained for different cases reveal that the extent of radiative interactions is reduced significantly under nonequilibrium conditions. The method developed can be easily extended to investigate radiative interactions in complex nonequilibrium flows.
Dynamics of convective scale interaction
NASA Technical Reports Server (NTRS)
Purdom, James F. W.; Sinclair, Peter C.
Several of the mesoscale dynamic and thermodynamic aspects of convective scale interaction are examined. An explanation of how sounding data can be coupled with satellite observed cumulus development in the warm sector and the arc cloud line's time evolution to develop a short range forecast of expected convective intensity along an arc cloud line. The formative, mature and dissipating stages of the arc cloud line life cycle are discussed. Specific properties of convective scale interaction are presented and the relationship between arc cloud lines and tornado producing thunderstorms is considered.
Interactive Multimedia: Practice and Promise.
ERIC Educational Resources Information Center
Latchem, Colin, Ed.; And Others
This book describes developments in interactive multimedia (IMM) in the early 1990s. Its aim is to provide educators, students, trainers, librarians, managers, and practitioners with an overview, not only of the directions and uses of the technology, but also of the research foundations and educational and contextual issues that need to be…
Inter-Action's Environmental Programmes.
ERIC Educational Resources Information Center
Knights, John
Describes the work of Inter-Action, a voluntary organization funded to explore ways in which creative arts can be applied to the resolution of social and environmental problems of the inner-city. Environmental projects for neighborhood residents focus on city farms, community architecture, family food production, concrete sculptures, and…
Education, Interaction, and Social Change.
ERIC Educational Resources Information Center
Hodgkinson, Harold L.
This book examines the interaction of education and other elements in our culture. The social system of education is seen as similar to that of such other formal social institutions as business. Moreover, an understanding of the role and function of education can be achieved through an application of social science theory and research findings.…
TIGER: Turbomachinery interactive grid generation
NASA Technical Reports Server (NTRS)
Soni, Bharat K.; Shih, Ming-Hsin; Janus, J. Mark
A three dimensional, interactive grid generation code, TIGER, is being developed for analysis of flows around ducted or unducted propellers. TIGER is a customized grid generator that combines new technology with methods from general grid generation codes. The code generates multiple block, structured grids around multiple blade rows with a hub and shroud for either C grid or H grid topologies. The code is intended for use with a Euler/Navier-Stokes solver also being developed, but is general enough for use with other flow solvers. TIGER features a silicon graphics interactive graphics environment that displays a pop-up window, graphics window, and text window. The geometry is read as a discrete set of points with options for several industrial standard formats and NASA standard formats. Various splines are available for defining the surface geometries. Grid generation is done either interactively or through a batch mode operation using history files from a previously generated grid. The batch mode operation can be done either with a graphical display of the interactive session or with no graphics so that the code can be run on another computer system. Run time can be significantly reduced by running on a Cray-YMP.
Literary Gaps Invite Creative Interaction.
ERIC Educational Resources Information Center
Watson, Jerry J.
Literary gaps were identified by Wolfgang Iser in 1974 as "vacant pages" that invite the reader to reflect and enter into the text thereby motivating students to experience the text as reality. Arthur Applebee, in 1979, identified three categories to distinguish children's types of interaction with stories: (1) the complexity of literary and…
Verbal Interaction in University Tutorials
ERIC Educational Resources Information Center
Baumgart, Neil
An attempt was made to describe the verbal interaction of 29 university tutorial groups. Tutor roles were identified (reflexive judge, data input, stage setter, elaborator, probe, and cognitive engineer) and examined in relationship to student ratings of the sessions and use by students of different cognitive levels. Applications of the research…
Interaction in Distance Nursing Education
ERIC Educational Resources Information Center
Boz Yuksekdag, Belgin
The purpose of this study is to determine psychiatry nurses' attitudes toward the interactions in distance nursing education, and also scrunize their attitudes based on demographics and computer/Internet usage. The comparative relational scanning model is the method of this study. The research data were collected through "The Scale of Attitudes of…
Interactive Whiteboards in Japanese Education
ERIC Educational Resources Information Center
Liversidge, Gordon
The use of interactive whiteboards (IWBs) is widespread in the United Kingdom, Australia, and to some extent in the United States and Canada. However, this potentially learning enhancing technology has been adopted very little in Japan at any level of education, apart from some international schools. Furthermore, one of the world's two leading IWB…
Gendered Language in Interactive Discourse
ERIC Educational Resources Information Center
Hussey, Karen A.; Katz, Albert N.; Leith, Scott A.
Over two studies, we examined the nature of gendered language in interactive discourse. In the first study, we analyzed gendered language from a chat corpus to see whether tokens of gendered language proposed in the gender-as-culture hypothesis (Maltz and Borker in "Language and social identity." Cambridge University Press, Cambridge, pp…
Percolation of interaction diffusing particles
NASA Technical Reports Server (NTRS)
Selinger, Robin Blumberg; Stanley, H. Eugene
The connectivity properties of systems of diffusing interacting particles with the blind and myopic diffusion rules are studied. It is found that the blind rule case is equivalent to the lattice gas with J = 0 in all dimensions. The connectivity properties of blind rule diffusion are described by random site percolation due to the fact that the density on neighboring sites is uncorrelated.
Demonstration of Data Interactive Publications
NASA Astrophysics Data System (ADS)
Domenico, B.; Weber, J.
This is a demonstration version of the talk given in session ESSI2.4 "Full lifecycle of data." For some years now, the authors have developed examples of online documents that allowed the reader to interact directly with datasets, but there were limitations that restricted the interaction to specific desktop analysis and display tools that were not generally available to all readers of the documents. Recent advances in web service technology and related standards are making it possible to develop systems for publishing online documents that enable readers to access, analyze, and display the data discussed in the publication from the perspective and in the manner from which the author wants it to be represented. By clicking on embedded links, the reader accesses not only the usual textual information in a publication, but also data residing on a local or remote web server as well as a set of processing tools for analyzing and displaying the data. With the option of having the analysis and display processing provided on the server (or in the cloud), there are now a broader set of possibilities on the client side where the reader can interact with the data via a thin web client, a rich desktop application, or a mobile platform "app." The presentation will outline the architecture of data interactive publications along with illustrative examples.
Electron spin from self interaction
Spavieri, G. |
The author explores the possibility that the electron self-interaction is the origin of the spin and of the radiative effects of QED. The electron is conceived as a charged, massless, point particle with a quantum or stochastic, internal motion about its center of mass and bound by a self-interaction potential. The hydrodynamic equations of motion describing the electron in its center of mass frame are related to non-Markovian stochastic equations recently used to derive the Schroedinger equation. By averaging over this stochastic internal motion and identifying the energy with the rest mass energy, the angular momentum exhibits properties characteristic of spin. The electromagnetic self-interactions added to the Hamiltonian of the particle correct the g factor to yield the anomalous value (g{minus}2)/2 {approx} 1159.7(2.3) X 10{sup {minus}6} in agreement with experiment. Calculations of other {open_quotes}radiative{close_quotes} effects including the Lamb shift are presented. The results obtained are finite and suggest that the QED corrections attributed to radiative effects could be obtained classically, i.e., without second quantization and renormalization, by complementing the Dirac theory with this self-interaction mechanism. The g factor dependence on the external magnetic field of this and other spin models is compared with that of QED, showing that these theories can be tested by the present precision measurements of the g factor. 33 refs., 2 tabs.
Children's Understanding of Social Interaction.
ERIC Educational Resources Information Center
Flapan, Dorothy
To investigate children's ability to describe and make inferences about feelings, thoughts, and intentions that occur in interpersonal relationships, 60 middle class girls were divided into three age groups: 6, 9, and 12 years. Each group viewed two sections of a movie portraying episodes of social interaction. After each section, the children…
Gender Influences in Classroom Interaction.
ERIC Educational Resources Information Center
Wilkinson, Louise Cherry, Ed.; Marrett, Cora B., Ed.
The 11 chapters comprising this work focus on the interactional influences that may be related to differential classroom experiences for males and females. The effects of contextual factors, teacher characteristics, and student characteristics are investigated. Addressed primarily to researchers, this information should prove useful to teachers,…
Early Mother-Child Interaction.
ERIC Educational Resources Information Center
d'Agostino, Micheline
This journal issue presents an overview of mother-child interaction during the first year of the child's life. Contents of the first section, which concern the development of the mother-child relationship, focus on the concept of the maternal instinct, mother and child during intrauterine life, birth of the child, the postnatal period (including…
Inelastic final-state interaction
Suzuki, Mahiko; Suzuki, Mahiko
The final-state interaction in multichannel decay processes is systematically studied with application to B decay in mind. Since the final-state interaction is intrinsically interwoven with the decay interaction in this case, no simple phase theorem like"Watson's theorem" holds for experimentally observed final states. We first examine in detail the two-channel problem as a toy-model to clarify the issues and to remedy common mistakes made in earlier literature. Realistic multichannel problems are too challenging for quantitative analysis. To cope with mathematical complexity, we introduce a method of approximation that is applicable to the case where one prominent inelastic channel dominates over all others. We illustrate this approximation method in the amplitude of the decay B to pi K fed by the intermediate states of a charmed meson pair. Even with our approximation we need more accurate information of strong interactions than we have now. Nonetheless we are able to obtain some insight in the issue and draw useful conclusions on general features on the strong phases.
Labeled Postings for Asynchronous Interaction
ERIC Educational Resources Information Center
ChanLin, Lih-Juan; Chen, Yong-Ting; Chan, Kung-Chi
The Internet promotes computer-mediated communications, and so asynchronous learning network systems permit more flexibility in time, space, and interaction than synchronous mode of learning. The key point of asynchronous learning is the materials for web-aided teaching and the flow of knowledge. This research focuses on improving online…
Interaction quenches of Fermi gases
Uhrig, Goetz S.
It is shown that the jump in the momentum distribution of Fermi gases evolves smoothly for small and intermediate times once an interaction between the fermions is suddenly switched on. The jump does not vanish abruptly. The loci in momentum space where the jumps occur are those of the noninteracting Fermi sea. No relaxation of the Fermi surface geometry takes place.
Probable warfarin and dapsone interaction.
Truong, Teresa; Haley, James
We describe a case of a 41-year-old woman who was stable for over a year on 22.5 mg/week of warfarin. At a follow-up visit, her international normalized ratio (INR) was found to be supratherapeutic at 3.9. Her only significant change was acyclovir initiation for shingles, and clindamycin and dapsone for infection on her right foot. An interaction report was run using Micromedex with no interactions reported. Sixteen percent of the weekly dose was held and maintenance dose was continued. Two weeks later, the INR remained supratherapeutic at 4.3, with discontinuation of clindamycin and dapsone, 5 days earlier, as the only change. This time an interaction report was run using Lexi-Comp, which identified an interaction between warfarin and dapsone. The INR has been therapeutic and stable since discontinuation of transient factors. It is hypothesized that warfarin and dapsone compete for binding on the CYP2C9 and CYP3A4 isoenzymes and therefore serum concentration of warfarin was elevated. PMID:21890570
Students and the Interactive Whiteboard
ERIC Educational Resources Information Center
Biró, Piroska
The spread of Interactive Whiteboards in Hungary has made students more curious, interested and motivated. The new digital generation claims reform and besides the traditional education they need digital material, extra knowledge since it is much easier to access extra information in connection with a particular curriculum. They spend a lot of…
Revisiting interaction in knowledge translation
Ginsburg, Liane R; Lewis, Steven; Zackheim, Lisa; Casebeer, Ann
Background Although the study of research utilization is not new, there has been increased emphasis on the topic over the recent past. Science push models that are researcher driven and controlled and demand pull models emphasizing users/decision-maker interests have largely been abandoned in favour of more interactive models that emphasize linkages between researchers and decisionmakers. However, despite these and other theoretical and empirical advances in the area of research utilization, there remains a fundamental gap between the generation of research findings and the application of those findings in practice. Methods Using a case approach, the current study looks at the impact of one particular interaction approach to research translation used by a Canadian funding agency. Results Results suggest there may be certain conditions under which different levels of decisionmaker involvement in research will be more or less effective. Four attributes are illuminated by the current case study: stakeholder diversity, addressability/actionability of results, finality of study design and methodology, and politicization of results. Future research could test whether these or other variables can be used to specify some of the conditions under which different approaches to interaction in knowledge translation are likely to facilitate research utilization. Conclusion This work suggests that the efficacy of interaction approaches to research translation may be more limited than current theory proposes and underscores the need for more completely specified models of research utilization that can help address the slow pace of change in this area. PMID:17971208
Interacting binaries. Lecture notes 1992.
NASA Astrophysics Data System (ADS)
Nussbaumer, H.; Orr, A.
These lecture notes represent a unique collection of information and references on current research on interacting binaries: S. N. Shore puts the emphasis on observations and their connection to relevant physics. He also discusses symbiotic stars. Cataclysmic variables are the subject of M. Livio's course, whereas E. P. J. van den Heuvel concentrates on more massive binaries and X-ray binaries.
Preschooler's Counting in Peer Interaction.
ERIC Educational Resources Information Center
Curtis, Reagan P.
For this experiment, part of a larger study on preschoolers' counting competence, 3-, 4-, and 5-year-olds played a counting game with their peers after becoming familiar with the game during structured interviews with an adult. It was expected that the symmetrical nature of peer interaction would allow children to display quantitative knowledge in…
JSC interactive basic accounting system
NASA Technical Reports Server (NTRS)
Spitzer, J. F.
Design concepts for an interactive basic accounting system (IBAS) are considered in terms of selecting the design option which provides the best response at the lowest cost. Modeling the IBAS workload and applying this workload to a U1108 EXEC 8 based system using both a simulation model and the real system is discussed.
Presently, there are minimal data available on the interaction between manufactured nanoparticles and biological tissues. The basic requirement for any risk assessment includes information on hazard (e.g. toxicity) and exposure (e.g. absorption). This proposal focuses on the h...
E-Mentoring Interaction Models
ERIC Educational Resources Information Center
Lenear, Phoebe E.
Little research has been conducted on electronic mentoring. Several traditional mentoring models exist; however, due to the novelty of the research area, no theoretical e-mentoring models appear in the literature. Using Moore's Theory of Transactional Distance as the theoretical framework, this research compared mentor-protege interaction,…
Interaction of Nanoparticles with Biofilms
In this work we have studied the interaction and adsorption of engineered nanoparticles such as TiO2, ZnO, CeO2 , and carbon nanotubes with biofilms. Biofilm is an extracellular polymeric substance coating comprised of living material and it is an aggregation of bacteria, algae, ...
Wave/current interaction model
NASA Technical Reports Server (NTRS)
Liu, A. K.
The wave-current interaction for the application to remote sensing data via numerical simulations and data comparison is modelled. Using the field data of surface current shear, wind condition and ambient wave spectrum, the numerical simulations of directional wave spectrum evolution were used to interpret and to compare with the aircraft data from Radar Ocean Wave Spectrometer (ROWS) and Surface Contour Radar (SCR) across the front during Frontal Air Sea Interaction Experiment (FASINEX). The wave-ice interaction was inspired by the observation of large amplitude waves hundreds of kms inside the ice pack in the Weddell Sea, resulting in breakup of the ice pack. The developed analysis of processes includes the refraction of waves at the pack edge, the effects of pack compression on wave propagation, wave train stability and buckling stability in the ice pack. Sources of pack compression and interaction between wave momentum and pack compression are investigated. Viscous camping of propagating waves in the marginal ice zone are also studied. The analysis suggests an explanation for the change in wave dispersion observed from the ship and the sequence of processes that cause ice pack breakup, pressure ridge formation and the formation of open bands of water.
Grid Interaction Technical Team Roadmap
The mission of the Grid Interaction Technical Team (GITT) is to support a transition scenario to large scale grid-connected vehicle charging with transformational technology, proof of concept and information dissemination. The GITT facilitates technical coordination and collaboration between vehicle-grid connectivity and communication activities among U.S. DRIVE government and industry partners.
Potential drug interactions with melatonin.
Papagiannidou, Eleni; Skene, Debra J; Ioannides, Costas
Possible interactions of melatonin with concurrently administered drugs were investigated in in vitro studies utilising human hepatic post-mitochondrial preparations; similar studies were conducted with rat preparations to ascertain whether rat is a suitable surrogate for human. Drugs were selected based not only on the knowledge that the 6-hydroxylation of exogenous melatonin, its principal pathway of metabolism, is mainly mediated by hepatic CYP1A2, but also on the likelihood of the drug being concurrently administered with melatonin. Hepatic preparations were incubated with either melatonin or 6-hydroxymelatonin in the presence and absence of a range of concentrations of interacting drug, and the production of 6-sulphatoxymelatonin monitored using a radioimmunoassay procedure. Of the drugs screened, only the potent CYP1A2 inhibitor 5-methoxypsoralen impaired the 6-melatonin hydroxylation at pharmacologically relevant concentrations, and is likely to lead to clinical interactions; diazepam, tamoxifen and acetaminophen (paracetamol) did not impair the metabolic conversion of melatonin to 6-sulphatoxymelatonin at concentrations attained following therapeutic administration. 17-Ethinhyloestradiol appeared not to suppress the 6-hydroxylation of melatonin but inhibited the sulphation of 6-hydroxymelatonin, but this is unlikely to result in an interaction following therapeutic intake of the steroid. Species differences in the inhibition of melatonin metabolism in human and rat hepatic post-mitochondrial preparations were evident implying that the rat may not be an appropriate surrogate of human in such studies. PMID:24732412
Work Cognitions in Multicultural Interaction.
ERIC Educational Resources Information Center
Holt, John; Keats, Daphne M.
Investigates the influence of ethnic cultural background and multicultural interaction for 120 males drawn from Aboriginal, Anglo-Saxon, Chinese, and Lebanese cultural communities in Australia. Responses to the Work Cognitions Questionnaire reveal differences in the structure of achievement goals and work values for the 4 groups of 30 subjects…
Interaction in the dark sector
NASA Astrophysics Data System (ADS)
del Campo, Sergio; Herrera, Ramón; Pavón, Diego
It may well happen that the two main components of the dark sector of the Universe, dark matter and dark energy, do not evolve separately but interact nongravitationally with one another. However, given our current lack of knowledge of the microscopic nature of these two components, there is no clear theoretical path to determine their interaction. Yet, over the years, phenomenological interaction terms have been proposed on mathematical simplicity and heuristic arguments. In this paper, based on the likely evolution of the ratio between the energy densities of these dark components, we lay down reasonable criteria to obtain phenomenological, useful, expressions of the said term independent of any gravity theory. We illustrate this with different proposals which seem compatible with the known evolution of the Universe at the background level. Likewise, we show that two possible degeneracies with noninteracting models are only apparent as they can be readily broken at the background level. Further, we analyze some interaction terms that appear in the literature.
Interactive Video Disc Orientation Documentation.
ERIC Educational Resources Information Center
Frost, William J.; And Others
This report provides the documentation for a proposed interactive videodisk to be produced for use in orienting freshman students to the Harvey A. Andruss Library of Bloomsburg University (Pennsylvania). A rationale for the project and a plan of action are followed by a production time line and tentative program outline. An outline of the library…
Interactive Cable Television. Final Report.
ERIC Educational Resources Information Center
Active Learning Systems, Inc., Minneapolis, MN.
This report describes an interactive video system developed by Active Learning Systems which utilizes a cable television (TV) network as its delivery system to transmit computer literacy lessons to high school and college students. The system consists of an IBM PC, Pioneer LDV 4000 videodisc player, and Whitney Supercircuit set up at the head end…
Affect Control in International Interactions
ERIC Educational Resources Information Center
Heise, David R.; Lerner, Steven J.
This research tests the proposition that national leaders generate international interactions in the process of maintaining sentiments about nations and international actions. The analysis deals with 1,934 international incidents in which one of 25 Middle Eastern nations responded twice within four weeks to an instigation by another of the 25…
Modeling Interactions in Small Groups
ERIC Educational Resources Information Center
Heise, David R.
A new theory of interaction within small groups posits that group members initiate actions when tension mounts between the affective meanings of their situational identities and impressions produced by recent events. Actors choose partners and behaviors so as to reduce the tensions. A computer model based on this theory, incorporating reciprocal…
Seven Statements on Interactive Video.
ERIC Educational Resources Information Center
Gastkemper, F.
This paper is concerned with the educational significance of interactive video. To clarify this, seven basic educational concepts are reviewed: (1) education and training are organized forms of learning; (2) goals and objectives can be grouped into the cognitive, affective, and psychomotor domains of learning; (3) education refers to learning…
Classroom Interaction and Language Output
ERIC Educational Resources Information Center
Wang, Qiaoying; Castro, Carolyn D.
This study investigates the effects of classroom interactions between a) students and students and b) students and teachers on the learning of English passivization by L1 Chinese adult learners of English as a foreign language during the language input and output treatments. In phase 1, both groups were asked to read and underline the input…
High Tech Breakthrough: Interactive Videodisc.
ERIC Educational Resources Information Center
Sturm, Rebecca
Explores use of interactive videodisc, which combines videotape in disc format, with its various video and audio information, and the computer, either as part of disc player or external interface. Examples of a variety of industrial/educational applications are cited: Library of Congress, inventory, physician instruction, University of Iowa. (8…
Pharmacokinetic interactions of cimetidine 1987.
Somogyi, A; Muirhead, M
The number of studies on drug interactions with cimetidine has increased at a rapid rate over the past 5 years, with many of the interactions being solely pharmacokinetic in origin. Very few studies have investigated the clinical relevance of such pharmacokinetic interactions by measuring pharmacodynamic responses or clinical endpoints. Apart from pharmacokinetic studies, invariably conducted in young, healthy subjects, there have been a large number of in vitro and in vivo animal studies, case reports, clinical observations and general reviews on the subject, which is tending to develop an industry of its own accord. Nevertheless, where specific mechanisms have been considered, these have undoubtedly increased our knowledge on the way in which humans eliminate xenobiotics. There is now sufficient information to predict the likelihood of a pharmacokinetic drug-drug interaction with cimetidine and to make specific clinical recommendations. Pharmacokinetic drug interactions with cimetidine occur at the sites of gastrointestinal absorption and elimination including metabolism and excretion. Cimetidine has been found to reduce the plasma concentrations of ketoconazole, indomethacin and chlorpromazine by reducing their absorption. In the case of ketoconazole the interaction was clinically important. Cimetidine does not inhibit conjugation mechanisms including glucuronidation, sulphation and acetylation, or deacetylation or ethanol dehydrogenation. It binds to the haem portion of cytochrome P-450 and is thus an inhibitor of phase I drug metabolism (i.e. hydroxylation, dealkylation). Although generally recognised as a nonspecific inhibitor of this type of metabolism, cimetidine does demonstrate some degree of specificity. To date, theophylline 8-oxidation, tolbutamide hydroxylation, ibuprofen hydroxylation, misonidazole demethylation, carbamazepine epoxidation, mexiletine oxidation and steroid hydroxylation have not been shown to be inhibited by cimetidine in humans but
Interactions of Pathological Hallmark Proteins
Oláh, Judit; Vincze, Orsolya; Virók, Dezső; Simon, Dóra; Bozsó, Zsolt; Tőkési, Natália; Horváth, István; Hlavanda, Emma; Kovács, János; Magyar, Anna; Szűcs, Mária; Orosz, Ferenc; Penke, Botond; Ovádi, Judit
The disordered tubulin polymerization promoting protein (TPPP/p25) was found to be co-enriched in neuronal and glial inclusions with α-synuclein in Parkinson disease and multiple system atrophy, respectively; however, co-occurrence of α-synuclein with β-amyloid (Aβ) in human brain inclusions has been recently reported, suggesting the existence of mixed type pathologies that could result in obstacles in the correct diagnosis and treatment. Here we identified TPPP/p25 as an interacting partner of the soluble Aβ oligomers as major risk factors for Alzheimer disease using ProtoArray human protein microarray. The interactions of oligomeric Aβ with proteins involved in the etiology of neurological disorders were characterized by ELISA, surface plasmon resonance, pelleting experiments, and tubulin polymerization assay. We showed that the Aβ42 tightly bound to TPPP/p25 (Kd = 85 nm) and caused aberrant protein aggregation by inhibiting the physiologically relevant TPPP/p25-derived microtubule assembly. The pair-wise interactions of Aβ42, α-synuclein, and tubulin were found to be relatively weak; however, these three components formed soluble ternary complex exclusively in the absence of TPPP/p25. The aggregation-facilitating activity of TPPP/p25 and its interaction with Aβ was monitored by electron microscopy with purified proteins by pelleting experiments with cell-free extracts as well as by confocal microscopy with CHO cells expressing TPPP/p25 or amyloid. The finding that the interaction of TPPP/p25 with Aβ can produce pathological-like aggregates is tightly coupled with unusual pathology of the Alzheimer disease revealed previously; that is, partial co-localization of Aβ and TPPP/p25 in the case of diffuse Lewy body disease with Alzheimer disease. PMID:21832049
Materials cohesion and interaction forces.
Rosenholm, Jarl B; Peiponen, Kai-Erik; Gornov, Evgeny
The most important methods to determine the cohesive interactions of materials and adhesive interactions between different substances are reviewed. The term cohesion is generalized as representing the unifying interaction forces of a single material and adhesion forces between different substances due to attraction. The aim is to interlink a number of frequently used interaction parameters in order to promote the understanding of materials research executed within different scientific (Material, Colloid, Sol-Gel and Nano) communities. The modern interdisciplinary research requires a removal of the historical obstacles represented by widely differing nomenclature used for the same material properties. The interaction parameters of different models are reviewed and representative numerical values computed from tabulated thermodynamic and spectroscopic material constants. The results are compared with published values. The models are grouped to represent single and two component systems, respectively. The latter group includes models for films on substrates and work of adhesion between liquids and solids. In most cases rather rough approximations have been employed, mostly relating to van der Waals substances for which the gas state is common reference state. In order to improve the predictability of the key Hamaker constant, a novel model for interpreting the dielectric spectrum is presented. The interrelation between thermodynamic, electronic, spectroscopic and dielectric parameters is illustrated by model calculations on typical inorganic materials of current interest as model compounds. The ionic solids are represented by NaCl and KCl, while ZnO, FeO, Fe(2)O(3), Fe(3)O(4), Al(2)O(3), SiO(2), TiO(2), ZrO(2), SnO, SnO(2) represent ceramic oxides and semiconductors. The model compounds thus illustrate the effect of bond type (covalent or ionic) and valence (charge number and sign) of the constituent elements. However, since the focus is placed on a phenomenological
Grapefruit juice–drug interactions
Bailey, David G; Malcolm, J; Arnold, O; David Spence, J
The novel finding that grapefruit juice can markedly augment oral drug bioavailability was based on an unexpected observation from an interaction study between the dihydropyridine calcium channel antagonist, felodipine, and ethanol in which grapefruit juice was used to mask the taste of the ethanol. Subsequent investigations showed that grapefruit juice acted by reducing presystemic felodipine metabolism through selective post-translational down regulation of cytochrome P450 3A4 (CYP3A4) expression in the intestinal wall. Since the duration of effect of grapefruit juice can last 24 h, repeated juice consumption can result in a cumulative increase in felodipine AUC and Cmax. The high variability of the magnitude of effect among individuals appeared dependent upon inherent differences in enteric CYP3A4 protein expression such that individuals with highest baseline CYP3A4 had the highest proportional increase. At least 20 other drugs have been assessed for an interaction with grapefruit juice. Medications with innately low oral bioavailability because of substantial presystemic metabolism mediated by CYP3A4 appear affected by grapefruit juice. Clinically relevant interactions seem likely for most dihydropyridines, terfenadine, saquinavir, cyclosporin, midazolam, triazolam and verapamil and may also occur with lovastatin, cisapride and astemizole. The importance of the interaction appears to be influenced by individual patient susceptibility, type and amount of grapefruit juice and administration-related factors. Although in vitro findings support the flavonoid, naringin, or the furanocoumarin, 6′,7′-dihydroxybergamottin, as being active ingredients, a recent investigation indicated that neither of these substances made a major contribution to grapefruit juice-drug interactions in humans. PMID:9723817
Effective interactions between fluid membranes
NASA Astrophysics Data System (ADS)
Lu, Bing-Sui; Podgornik, Rudolf
A self-consistent theory is proposed for the general problem of interacting undulating fluid membranes subject to the constraint that they do not interpenetrate. We implement the steric constraint via an exact functional integral representation and, through the use of a saddle-point approximation, transform it into a novel effective steric potential. The steric potential is found to consist of two contributions: one generated by zero-mode fluctuations of the membranes and the other by thermal bending fluctuations. For membranes of cross-sectional area S , we find that the bending fluctuation part scales with the intermembrane separation d as d-2 for d ≪√{S } but crosses over to d-4 scaling for d ≫√{S } , whereas the zero-mode part of the steric potential always scales as d-2. For membranes interacting exclusively via the steric potential, we obtain closed-form expressions for the effective interaction potential and for the rms undulation amplitude σ , which becomes small at low temperatures T and/or large bending stiffnesses κ . Moreover, σ scales as d for d ≪√{S } but saturates at √{kBT S /κ } for d ≫√{S } . In addition, using variational Gaussian theory, we apply our self-consistent treatment to study intermembrane interactions subject to different types of potentials: (i) the Moreira-Netz potential for a pair of strongly charged membranes with an intervening solution of multivalent counterions, (ii) an attractive square well, (iii) the Morse potential, and (iv) a combination of hydration and van der Waals interactions.
Effective interactions between fluid membranes.
Lu, Bing-Sui; Podgornik, Rudolf
A self-consistent theory is proposed for the general problem of interacting undulating fluid membranes subject to the constraint that they do not interpenetrate. We implement the steric constraint via an exact functional integral representation and, through the use of a saddle-point approximation, transform it into a novel effective steric potential. The steric potential is found to consist of two contributions: one generated by zero-mode fluctuations of the membranes and the other by thermal bending fluctuations. For membranes of cross-sectional area S, we find that the bending fluctuation part scales with the intermembrane separation d as d-2 for d≪√S but crosses over to d-4 scaling for d≫√S, whereas the zero-mode part of the steric potential always scales as d-2. For membranes interacting exclusively via the steric potential, we obtain closed-form expressions for the effective interaction potential and for the rms undulation amplitude σ, which becomes small at low temperatures T and/or large bending stiffnesses κ. Moreover, σ scales as d for d≪√S but saturates at √kBTS/κ for d≫√S. In addition, using variational Gaussian theory, we apply our self-consistent treatment to study intermembrane interactions subject to different types of potentials: (i) the Moreira-Netz potential for a pair of strongly charged membranes with an intervening solution of multivalent counterions, (ii) an attractive square well, (iii) the Morse potential, and (iv) a combination of hydration and van der Waals interactions. PMID:26382349
Spectra, composition, and interactions of nuclei with magnet interaction chambers
NASA Technical Reports Server (NTRS)
Parneil, T. A.; Derrickson, J. H.; Fountain, W. F.; Roberts, F. E.; Tabuki, T.; Watts, J. W.; Burnett, T. H.; Cherry, M. C.; Dake, S.; Fuki, M.
Emulsion chambers will be flown in the Astromag Facility to measure the cosmic ray composition and spectra to 10 exp 15 eV total energy and to definitively study the characteristics of nucleus-nucleus interactions above 10 exp 12 eV/n. Two configurations of emulsion chambers will be flown in the SCIN/MAGIC experiment. One chamber has an emulsion target and a calorimeter similar to those recently flown on balloons for composition and spectra measurements. The other has an identical calorimeter and a low-density target section optimized for performing rigidity measurements on charged particles produced in interactions. The transverse momenta of charged and neutral mesons, direct hadronic pairs from resonance decays and interference effects, and possible charge clustering in high-density states of matter will be studied.
Independent pair parton interactions model of hadron interactions
NASA Astrophysics Data System (ADS)
Dremin, I. M.; Nechitailo, V. A.
A model of independent pair parton interactions is proposed, according to which hadron interactions are represented by a set of independent binary parton collisions. The final multiplicity distribution is described by a convolution of the negative binomial distributions in each of the partonic collisions. As a result, it is given by a weighted sum of negative binomial distributions with parameters multiplied by the number of active pairs. Its shape and moments are considered. Experimental data on multiplicity distributions in high energy pp¯ processes are well fitted by these distributions. Predictions for the CERN Large Hadron Collider and higher energies are presented. The difference between e+e- and pp¯ processes is discussed.
Interaction in Information Searching and Retrieval.
ERIC Educational Resources Information Center
Beaulieu, Micheline
Explores the concepts of interaction and interactivity presented in different theoretical models in the fields of human-computer interaction (HCI) and information-seeking/searching behavior, and relates these to information retrieval (IR) research. Suggests that interaction in HCI is primarily concerned with establishing a user/system dialogue at…
The Interaction Hypothesis: A Critical Evaluation.
ERIC Educational Resources Information Center
Ellis, Rod
The oral interaction hypothesis, proposed by Long and investigated by Pica, in second language (L2) acquisition is critiqued. The interaction hypothesis advances two major claims about the role of interaction in L2 acquisition: (1) comprehensible input is necessary for L2 acquisition; and (2) modifications to the interactional structure of…
Adolescent Girls' Parasocial Interactions with Media Figures
ERIC Educational Resources Information Center
Theran, Sally A.; Newberg, Emily M.; Gleason, Tracy R.
We examined aspects of adolescent girls' parasocial interactions in the context of typical development. Parasocial interactions are defined as symbolic, one-sided quasi-interactions between a viewer and a media figure. In total, 107 adolescent girls were examined; 94% reported engaging in parasocial interactions to some degree. Preoccupied…
Discriminant Analysis of Family Interaction During Play.
ERIC Educational Resources Information Center
Provencher, Darell C.; Beauchamp, Kenneth L.
Discriminant analysis was used to explore the influence of the relative ages of siblings on their dyadic interactions, and to explore which interaction behaviors might discriminate among families and among interaction situations. Six dyadic interaction situations of 30 minutes duration were observed among members of 12 normal families. The…
Pharmacokinetic drug interactions of macrolides.
Periti, P; Mazzei, T; Mini, E; Novelli, A
The macrolide antibiotics include natural members, prodrugs and semisynthetic derivatives. These drugs are indicated in a variety of infections and are often combined with other drug therapies, thus creating the potential for pharmacokinetic interactions. Macrolides can both inhibit drug metabolism in the liver by complex formation and inactivation of microsomal drug oxidising enzymes and also interfere with microorganisms of the enteric flora through their antibiotic effects. Over the past 20 years, a number of reports have incriminated macrolides as a potential source of clinically severe drug interactions. However, differences have been found between the various macrolides in this regard and not all macrolides are responsible for drug interactions. With the recent advent of many semisynthetic macrolide antibiotics it is now evident that they may be classified into 3 different groups in causing drug interactions. The first group (e.g. troleandomycin, erythromycins) are those prone to forming nitrosoalkanes and the consequent formation of inactive cytochrome P450-metabolite complexes. The second group (e.g. josamycin, flurithromycin, roxithromycin, clarithromycin, miocamycin and midecamycin) form complexes to a lesser extent and rarely produce drug interactions. The last group (e.g. spiramycin, rokitamycin, dirithromycin and azithromycin) do not inactivate cytochrome P450 and are unable to modify the pharmacokinetics of other compounds. It appears that 2 structural factors are important for a macrolide antibiotic to lead to the induction of cytochrome P450 and the formation in vivo or in vitro of an inhibitory cytochrome P450-iron-nitrosoalkane metabolite complex: the presence in the macrolide molecules of a non-hindered readily accessible N-dimethylamino group and the hydrophobic character of the drug. Troleandomycin ranks first as a potent inhibitor of microsomal liver enzymes, causing a significant decrease of the metabolism of methylprednisolone, theophylline
Interactive Conversion of Web Tables
NASA Astrophysics Data System (ADS)
Padmanabhan, Raghav Krishna; Jandhyala, Ramana Chakradhar; Krishnamoorthy, Mukkai; Nagy, George; Seth, Sharad; Silversmith, William
Two hundred web tables from ten sites were imported into Excel. The tables were edited as needed, then converted into layout independent Wang Notation using the Table Abstraction Tool (TAT). The output generated by TAT consists of XML files to be used for constructing narrow-domain ontologies. On an average each table required 104 seconds for editing. Augmentations like aggregates, footnotes, table titles, captions, units and notes were also extracted in an average time of 93 seconds. Every user intervention was logged and audited. The logged interactions were analyzed to determine the relative influence of factors like table size, number of categories and various types of augmentations on the processing time. The analysis suggests which aspects of interactive table processing can be automated in the near term, and how much time such automation would save. The correlation coefficient between predicted and actual processing time was 0.66.
The Interaction-Activity Connection
NASA Technical Reports Server (NTRS)
Borne, Kirk D.
A review is presented of the numerous studies that have been undertaken to investigate the likely interaction-activity connection among galaxies. Both observational evidence and theoretical supporting models are reviewed. Some specific examples of "interactive" galaxies from the author's own research are presented: (a) the collision-induced AGN (Active Galactic Nuclei) activity in the radio jet source 3C278; and (b) the collision-induced starburst activity in the spectacular "Cartwheel" ring galaxy. Some comments are offered concerning some of the more promising theoretical investigations that are now taking place. A few words of warning are also offered about the possible misinterpretation of putative collision-induced morphologies among some galaxy samples.
Hydrodynamic interactions between rotating helices.
Kim, MunJu; Powers, Thomas R
Escherichia coli bacteria use rotating helical flagella to swim. At this scale, viscous effects dominate inertia, and there are significant hydrodynamic interactions between nearby helices. These interactions cause the flagella to bundle during the "runs" of bacterial chemotaxis. Here we use slender-body theory to solve for the flow fields generated by rigid helices rotated by stationary motors. We determine how the hydrodynamic forces and torques depend on phase and phase difference, show that rigid helices driven at constant torque do not synchronize, and solve for the flows. We also use symmetry arguments based on kinematic reversibility to show that for two rigid helices rotating with zero phase difference, there is no time-averaged attractive or repulsive force between the helices. PMID:15244620
Arabidopsis thaliana—Aphid Interaction
Louis, Joe; Singh, Vijay; Shah, Jyoti
Aphids are important pests of plants that use their stylets to tap into the sieve elements to consume phloem sap. Besides the removal of photosynthates, aphid infestation also alters source-sink patterns. Most aphids also vector viral diseases. In this chapter, we will summarize on recent significant findings in plant-aphid interaction, and how studies involving Arabidopsis thaliana and Myzus persicae (Sülzer), more commonly known as the green peach aphid (GPA), are beginning to provide important insights into the molecular basis of plant defense and susceptibility to aphids. The recent demonstration that expression of dsRNA in Arabidopsis can be used to silence expression of genes in GPA has further expanded the utility of Arabidopsis for evaluating the contribution of the aphid genome-encoded proteins to this interaction. PMID:22666177
Bragg interactions in periodic media
NASA Technical Reports Server (NTRS)
Jaggard, D. L.
The interaction of electromagnetic waves of wavelength lambda with periodic structures of spatial period lambda are studied. The emphasis of the work is on Bragg interactions where lambda approximately equal to 2 lambda/N and the Bragg order N takes on the values 1, 2,.... An extended coupled waves (ECW) theory is developed for the case N greater or equal to 2 and the results of the theory are found to compare favorably with the exact results of Floquet theory. Numerous numerical results are displayed as Brillouin diagrams for the first few Bragg orders. Moreover, explicit expressions for coupling coefficients, bandgap shifts and bandgap widths are derived for singly periodic media. Particular note is taken of phase speeding effects.
OVERFLOW-Interaction with Industry
NASA Technical Reports Server (NTRS)
Buning, Pieter G.; George, Michael W. (Technical Monitor)
A Navier-Stokes flow solver, OVERFLOW, has been developed by researchers at NASA Ames Research Center to use overset (Chimera) grids to simulate the flow about complex aerodynamic shapes. Primary customers of the OVERFLOW flow solver and related software include McDonnell Douglas and Boeing, as well as the NASA Focused Programs for Advanced Subsonic Technology (AST) and High Speed Research (HSR). Code development has focused on customer issues, including improving code performance, ability to run on workstation clusters and the NAS SP2, and direct interaction with industry on accuracy assessment and validation. Significant interaction with NAS has produced a capability tailored to the Ames computing environment, and code contributions have come from a wide range of sources, both within and outside Ames.
Bien, Jacob; Taylor, Jonathan; Tibshirani, Robert
We add a set of convex constraints to the lasso to produce sparse interaction models that honor the hierarchy restriction that an interaction only be included in a model if one or both variables are marginally important. We give a precise characterization of the effect of this hierarchy constraint, prove that hierarchy holds with probability one and derive an unbiased estimate for the degrees of freedom of our estimator. A bound on this estimate reveals the amount of fitting "saved" by the hierarchy constraint. We distinguish between parameter sparsity—the number of nonzero coefficients—and practical sparsity—the number of raw variables one must measure to make a new prediction. Hierarchy focuses on the latter, which is more closely tied to important data collection concerns such as cost, time and effort. We develop an algorithm, available in the R package hierNet, and perform an empirical study of our method. PMID:26257447
Interactive displays in medical art
NASA Technical Reports Server (NTRS)
Mcconathy, Deirdre Alla; Doyle, Michael
Medical illustration is a field of visual communication with a long history. Traditional medical illustrations are static, 2-D, printed images; highly realistic depictions of the gross morphology of anatomical structures. Today medicine requires the visualization of structures and processes that have never before been seen. Complex 3-D spatial relationships require interpretation from 2-D diagnostic imagery. Pictures that move in real time have become clinical and research tools for physicians. Medical illustrators are involved with the development of interactive visual displays for three different, but not discrete, functions: as educational materials, as clinical and research tools, and as data bases of standard imagery used to produce visuals. The production of interactive displays in the medical arts is examined.
Artificial graphene with tunable interactions.
Uehlinger, Thomas; Jotzu, Gregor; Messer, Michael; Greif, Daniel; Hofstetter, Walter; Bissbort, Ulf; Esslinger, Tilman
We create an artificial graphene system with tunable interactions and study the crossover from metallic to Mott insulating regimes, both in isolated and coupled two-dimensional honeycomb layers. The artificial graphene consists of a two-component spin mixture of an ultracold atomic Fermi gas loaded into a hexagonal optical lattice. For strong repulsive interactions, we observe a suppression of double occupancy and measure a gapped excitation spectrum. We present a quantitative comparison between our measurements and theory, making use of a novel numerical method to obtain Wannier functions for complex lattice structures. Extending our studies to time-resolved measurements, we investigate the equilibration of the double occupancy as a function of lattice loading time. PMID:24237536
Research in interactive scene analysis
NASA Technical Reports Server (NTRS)
Tenenbaum, J. M.; Garvey, T. D.; Weyl, S. A.; Wolf, H. C.
An interactive scene interpretation system (ISIS) was developed as a tool for constructing and experimenting with man-machine and automatic scene analysis methods tailored for particular image domains. A recently developed region analysis subsystem based on the paradigm of Brice and Fennema is described. Using this subsystem a series of experiments was conducted to determine good criteria for initially partitioning a scene into atomic regions and for merging these regions into a final partition of the scene along object boundaries. Semantic (problem-dependent) knowledge is essential for complete, correct partitions of complex real-world scenes. An interactive approach to semantic scene segmentation was developed and demonstrated on both landscape and indoor scenes. This approach provides a reasonable methodology for segmenting scenes that cannot be processed completely automatically, and is a promising basis for a future automatic system. A program is described that can automatically generate strategies for finding specific objects in a scene based on manually designated pictorial examples.
Peer interaction: help or distraction?
NASA Astrophysics Data System (ADS)
Ruzhitskaya, Lanika; Speck, A.; Dr.
We present our results on the difference in learning effectiveness of a particular concept in astronomy when students work as individuals as compared to working in pairs. We conducted a study based on the stellar parallax concept using two versions of a computer-based tutorial: guided and unguided. In this study students were randomly assigned to work in peer groups and individually. Students' interactions with the two versions of the tutorial and their peer interactions were recorded using MORAE software for quantitative and qualitative analysis. In addition, we used pretest and two posttest questionnaires to find conceptual gain. Here we present our preliminary results on the emergence of particular patterns in students learning behavior when they work independently and with peers, and how guided or unguided exercises affect these patterns.
Image reproduction with interactive graphics
NASA Technical Reports Server (NTRS)
Buckner, J. D.; Council, H. W.; Edwards, T. R.
Software application or development in optical image digital data processing requires a fast, good quality, yet inexpensive hard copy of processed images. To achieve this, a Cambo camera with an f 2.8/150-mm Xenotar lens in a Copal shutter having a Graflok back for 4 x 5 Polaroid type 57 pack-film has been interfaced to an existing Adage, AGT-30/Electro-Mechanical Research, EMR 6050 graphic computer system. Time-lapse photography in conjunction with a log to linear voltage transformation has resulted in an interactive system capable of producing a hard copy in 54 sec. The interactive aspect of the system lies in a Tektronix 4002 graphic computer terminal and its associated hard copy unit.
Interactive Learning During Solar Maximum
NASA Technical Reports Server (NTRS)
Ashour-Abdalla, Maha; Curtis, Steven (Technical Monitor)
The goal of this project is to develop and distribute e-educational material for space science during times of solar activity that emphasizes underlying basic science principles of solar disturbances and their effects on Earth. This includes materials such as simulations, animations, group projects and other on-line materials to be used by students either in high school or at the introductory college level. The on-line delivery tool originally intended to be used is known as Interactive Multimedia Education at a Distance (IMED), which is a web-based software system used at UCLA for interactive distance learning. IMED is a password controlled system that allows students to access text, images, bulletin boards, chat rooms, animation, simulations and individual student web sites to study science and to collaborate on group projects.
Bacterial interactions in dental biofilm.
Huang, Ruijie; Li, Mingyun; Gregory, Richard L
Biofilms are masses of microorganisms that bind to and multiply on a solid surface, typically with a fluid bathing the microbes. The microorganisms that are not attached but are free floating in an aqueous environment are termed planktonic cells. Traditionally, microbiology research has addressed results from planktonic bacterial cells. However, many recent studies have indicated that biofilms are the preferred form of growth of most microbes and particularly those of a pathogenic nature. Biofilms on animal hosts have significantly increased resistance to various antimicrobials compared to planktonic cells. These microbial communities form microcolonies that interact with each other using very sophisticated communication methods (i.e., quorum-sensing). The development of unique microbiological tools to detect and assess the various biofilms around us is a tremendously important focus of research in many laboratories. In the present review, we discuss the major biofilm mechanisms and the interactions among oral bacteria. PMID:21778817
Nonlinear interaction between single photons.
Guerreiro, T; Martin, A; Sanguinetti, B; Pelc, J S; Langrock, C; Fejer, M M; Gisin, N; Zbinden, H; Sangouard, N; Thew, R T
Harnessing nonlinearities strong enough to allow single photons to interact with one another is not only a fascinating challenge but also central to numerous advanced applications in quantum information science. Here we report the nonlinear interaction between two single photons. Each photon is generated in independent parametric down-conversion sources. They are subsequently combined in a nonlinear waveguide where they are converted into a single photon of higher energy by the process of sum-frequency generation. Our approach results in the direct generation of photon triplets. More generally, it highlights the potential for quantum nonlinear optics with integrated devices and, as the photons are at telecom wavelengths, it opens the way towards novel applications in quantum communication such as device-independent quantum key distribution. PMID:25379916
Astronomy education through interactive materials
NASA Astrophysics Data System (ADS)
Voelzke, Marcos Rincon; Antunes de Macêdo, Josué
This study presents results of a survey conducted at the Federal Institution of Education, Science and Technology in the North of Minas Gerais (IFNMG), and aimed to investigate the potentialities of the use of interactive materials in the teaching of astronomy. An advanced training course with involved learning activities about basic concepts of astronomy was offered to thirty-two Licenciate students in Physics, Mathematics and Biological Sciences, using the mixed methodology, combined with the three pedagogical moments. Among other aspects, the viability of the use of resources was noticed, involving digital technologies and interactive materials on teaching of astronomy, which may contribute to the broadening of methodological options for future teachers and meet their training needs.
Extraterrestrial Studies Using Nuclear Interactions
NASA Technical Reports Server (NTRS)
Reedy, Robert C.
Cosmogenic nuclides were used to study the recent histories of the aubrite Norton County and the pallasite Brenham using calculated production rates. Calculations were done of the rates for making cosmogenic noble-gas isotopes in the Jovian satellite Europa by the interactions of galactic cosmic rays and especially trapped Jovian protons. Cross sections for the production of cosmogenic nuclides were reported and plans made to measure additional cross sections. A new code, MCNPX, was used to numerically simulate the interactions of cosmic rays with matter and the subsequent production of cosmogenic nuclides. A review was written about studies of extraterrestrial matter using cosmogenic radionuclides. Several other projects were done. Results are reviewed here with references to my recent publications for details.
Gogny interactions with tensor terms
NASA Astrophysics Data System (ADS)
Anguiano, M.; Lallena, A. M.; Co', G.; De Donno, V.; Grasso, M.; Bernard, R. N.
We present a perturbative approach to include tensor terms in the Gogny interaction. We do not change the values of the usual parameterisations, with the only exception of the spin-orbit term, and we add tensor terms whose only free parameters are the strengths of the interactions. We identify observables sensitive to the presence of the tensor force in Hartree-Fock, Hartree-Fock-Bogoliubov and random phase approximation calculations. We show the need of including two tensor contributions, at least: a pure tensor term and a tensor-isospin term. We show results relevant for the inclusion of the tensor term for single-particle energies, charge-conserving magnetic excitations and Gamow-Teller excitations.
Golgi: Interactive Online Brain Mapping.
Brown, Ramsay A; Swanson, Larry W
Golgi (http://www.usegolgi.com) is a prototype interactive brain map of the rat brain that helps researchers intuitively interact with neuroanatomy, connectomics, and cellular and chemical architecture. The flood of "-omic" data urges new ways to help researchers connect discrete findings to the larger context of the nervous system. Here we explore Golgi's underlying reasoning and techniques and how our design decisions balance the constraints of building both a scientifically useful and usable tool. We demonstrate how Golgi can enhance connectomic literature searches with a case study investigating a thalamocortical circuit involving the Nucleus Accumbens and we explore Golgi's potential and future directions for growth in systems neuroscience and connectomics. PMID:26635596
An interactive online robotics course.
Wedeward, Kevin; Bruder, Steven B. H.
Attempting to convey concepts and ideas in the subject area of robotic manipulators from within the confines of a static two-dimensional printed page can prove quite challenging to even the most gifted of authors. The inherently dynamic and multi-dimensional nature of the subject matter seems better suited to a medium of conveyance wherein a student is allowed to interactively explore topics in this multi-disciplinary field. This article describes the initial development of an online robotics course 'textbook' which seeks to leverage recent advances in Web-based technologies to enhance the learning experience in ways not possible with printed materials. The pedagogical approach employed herein is that of multi-modal reinforcement wherein key concepts are first described in words, conveyed visually, and finally reinforced by soliciting student interaction.
Bacterial interactions in dental biofilm
Huang, Ruijie; Li, Mingyun
Biofilms are masses of microorganisms that bind to and multiply on a solid surface, typically with a fluid bathing the microbes. The microorganisms that are not attached but are free-floating in an aqueous environment are termed planktonic cells. Traditionally, microbiology research has addressed results from planktonic bacterial cells. However, many recent studies have indicated that biofilms are the preferred form of growth of most microbes and particularly those of a pathogenic nature. Biofilms on animal hosts have significantly increased resistance to various antimicrobials compared to planktonic cells. These microbial communities form microcolonies that interact with each other using very sophisticated communication methods (i.e., quorum-sensing). The development of unique microbiological tools to detect and assess the various biofilms around us is a tremendously important focus of research in many laboratories. In the present review, we discuss the major biofilm mechanisms and the interactions among oral bacteria. PMID:21778817
Positrons from accelerated particle interactions
NASA Technical Reports Server (NTRS)
Kozlovsky, B.; Lingenfelter, R. E.; Ramaty, R.
Positron production from the decay of radioactive nuclei produced in nuclear interactions of accelerated particles is treated in detail. Laboratory data as well as theoretical considerations are used to construct energy-dependent cross sections for the production of a large number of radioactive positron emitters resulting from proton and alpha-particle interactions with ambient cosmic matter. Using these cross sections, positron production rates are calculated for a variety of energetic particle spectra, assuming solar abundances for both the energetic particles and the ambient medium. These results can be used for the study of astrophysical sites which emit annihilation radiation. In particular, the results have been applied to solar flares, where the observed 0.511 MeV line is shown to be due to positrons resulting from accelerated particle reactions.
Airframe noise component interaction studies
NASA Technical Reports Server (NTRS)
Fink, M. R.; Schlinker, R. H.
Acoustic wind tunnel tests were conducted to examine the noise-generating processes of an airframe during approach flight. The airframe model was a two-dimensional wing section, to which highlift leading and trailing edge devices and landing gear could be added. Far field conventional microphones were utilized to determine component spectrum levels. An acoustic mirror directional microphone was utilized to examine noise source distributions on airframe components extended separately and in combination. Measured quantities are compared with predictions inferred from aircraft flyover data. Aeroacoustic mechanisms for each airframe component are identified. Component interaction effects on total radiated noise generally were small (within about 2 dB). However, some interactions significantly redistributed the local noise source strengths by changing local flow velocities and turbulence levels. Possibilities for noise reduction exist if trailing edge flaps could be modified to decrease their noise radiation caused by incident turbulent flow.
Improved productivity through interactive communication
NASA Technical Reports Server (NTRS)
Marino, P. P.
New methods and approaches are being tried and evaluated with the goal of increasing productivity and quality. The underlying concept in all of these approaches, methods or processes is that people require interactive communication to maximize the organization's strengths and minimize impediments to productivity improvement. This paper examines Bendix Field Engineering Corporation's organizational structure and experiences with employee involvement programs. The paper focuses on methods Bendix developed and implemented to open lines of communication throughout the organization. The Bendix approach to productivity and quality enhancement shows that interactive communication is critical to the successful implementation of any productivity improvement program. The paper concludes with an examination of the Bendix methodologies which can be adopted by any corporation in any industry.
Unified theory of effective interaction
NASA Astrophysics Data System (ADS)
Takayanagi, Kazuo
We present a unified description of effective interaction theories in both algebraic and graphic representations. In our previous work, we have presented the Rayleigh-Schrödinger and Bloch perturbation theories in a unified fashion by introducing the main frame expansion of the effective interaction. In this work, we start also from the main frame expansion, and present various nonperturbative theories in a coherent manner, which include generalizations of the Brandow, Brillouin-Wigner, and Bloch-Horowitz theories on the formal side, and the extended Krenciglowa-Kuo and the extended Lee-Suzuki methods on the practical side. We thus establish a coherent and comprehensive description of both perturbative and nonperturbative theories on the basis of the main frame expansion.
Pellet interaction with runaway electrons
James, A. N.; Hollmann, E. M.; Yu, J.H.; Austin, M. E.; Commaux, Nicolas JC; Evans, T.E.; Humphrey, D. A.; Jernigan, T. C.; Parks, P. B.; Putvinski, S.; Strait, E. J.; Tynan, G. R.; Wesley, J. C.
We describe results from recent experiments studying interaction of solid polystyrene pellets with a runaway electron current channel generated after cryogenic argon pellet rapid shutdown of DIII-D. Fast camera imaging shows the pellet trajectory and continuum emission from the subsequent explosion, with geometric calibration providing detailed explosion analysis and runaway energy. Electron cyclotron emission also occurs, associated with knock-on electrons broken free from the pellet by RE which then accelerate and runaway, and also with a short lived hot plasma blown off the pellet surface. In addition, we compare heating and explosion times from observations and a model of pellet heating and breakdown by runaway interaction. (C) 2011 Elsevier B.V. All rights reserved
Rotor-vortex interaction noise
NASA Technical Reports Server (NTRS)
Schlinker, R. H.; Amiet, R. K.
A theoretical and experimental study was conducted to develop a validated first principles analysis for predicting noise generated by helicopter main-rotor shed vortices interacting with the tail rotor. The generalized prediction procedure requires a knowledge of the incident vortex velocity field, rotor geometry, and rotor operating conditions. The analysis includes compressibility effects, chordwise and spanwise noncompactness, and treats oblique intersections with the blade planform. Assessment of the theory involved conducting a model rotor experiment which isolated the blade-vortex interaction noise from other rotor noise mechanisms. An isolated tip vortex, generated by an upstream semispan airfoil, was convected into the model tail rotor. Acoustic spectra, pressure signatures, and directivity were measured. Since assessment of the acoustic prediction required a knowledge of the vortex properties, blade-vortes intersection angle, intersection station, vortex stength, and vortex core radius were documented. Ingestion of the vortex by the rotor was experimentally observed to generate harmonic noise and impulsive waveforms.
Golgi: Interactive Online Brain Mapping
Brown, Ramsay A.; Swanson, Larry W.
Golgi (http://www.usegolgi.com) is a prototype interactive brain map of the rat brain that helps researchers intuitively interact with neuroanatomy, connectomics, and cellular and chemical architecture. The flood of "-omic" data urges new ways to help researchers connect discrete findings to the larger context of the nervous system. Here we explore Golgi's underlying reasoning and techniques and how our design decisions balance the constraints of building both a scientifically useful and usable tool. We demonstrate how Golgi can enhance connectomic literature searches with a case study investigating a thalamocortical circuit involving the Nucleus Accumbens and we explore Golgi's potential and future directions for growth in systems neuroscience and connectomics. PMID:26635596
Epistatic interactions and drug response.
Weigelt, Britta; Reis-Filho, Jorge S
The advent of massively parallel sequencing has allowed for an unprecedented genetic characterization of cancers, which has revealed not only the complexity of cancer genomes, but also the fact that tumours from the same anatomical site or even of the same histological and/or molecular subtype display distinct constellations of somatic genetic aberrations. Epistatic interactions (ie the interplay between genetic aberrations) are likely to play pivotal roles not only in terms of tumourigenesis and disease progression, but also in response to therapeutic interventions. In this review, we discuss the challenges posed by the complexity of tumour genomes and epistatic interactions, and approaches for harnessing the wealth of genetic information on human cancers for the implementation of precision medicine. PMID:24105606
Comparative assessment of four drug interaction compendia
Vitry, Agnes I
Aims To assess the consistency of inclusion and grading of major drug interactions for 50 drugs in four leading international drug interaction compendia. Methods Four international drug interaction compendia were compared: the drug interactions appendix of the British National Formulary, the interaction supplement in the French drug compendium Vidal, and two US drug interaction compendia, Drug Interaction Facts and the Micromedex (Drug-Reax) program. Major interactions were defined as potentially hazardous in BNF or with the warning 'contraindication' or 'avoid' in Vidal or with the significance grading 1 or 2 in DIF. Major interactions for a list of 50 drugs were searched in all four compendia. Results A total of 1264 interactions meeting the inclusion criteria were identified for these 50 drugs. After deletion of 169 duplicates, 1095 interactions were included in the analysis. Of the drug interactions classified as major in any one compendium between 14% and 44% were not listed in the other compendia. The grading systems used for the severity and the quality of the supporting evidence in Micromedex and DIF were inconsistent. Conclusions There is a lack of consistency in the inclusion and grading of drug interactions of major significance for 50 drugs across the four drug compendia examined. This may reflect the lack of standardization of the terminology used to classify drug interactions and the lack of good epidemiological evidence on which to base the assessment of the clinical relevance of drug interactions. PMID:17166171
Acoustoelasticity. [sound-structure interaction
NASA Technical Reports Server (NTRS)
Dowell, E. H.
Sound or pressure variations inside bounded enclosures are investigated. Mathematical models are given for determining: (1) the interaction between the sound pressure field and the flexible wall of a Helmholtz resonator; (2) coupled fluid-structural motion of an acoustic cavity with a flexible and/or absorbing wall; (3) acoustic natural modes in multiple connected cavities; and (4) the forced response of a cavity with a flexible and/or absorbing wall. Numerical results are discussed.
Strongly interacting parton matter equilibration
Ozvenchuk, V.; Linnyk, O.; Bratkovskaya, E.; Gorenstein, M.; Cassing, W.
We study the kinetic and chemical equilibration in 'infinite' parton matter within the Parton-Hadron-String Dynamics transport approach. The 'infinite' matter is simulated within a cubic box with periodic boundary conditions initialized at different energy densities. Particle abundances, kinetic energy distributions, and the detailed balance of the off-shell quarks and gluons in the strongly-interacting quarkgluon plasma are addressed and discussed.
An interactive image processing system.
Troxel, D E
A multiuser multiprocessing image processing system has been developed. It is an interactive picture manipulation and enhancement facility which is capable of executing a variety of image processing operations while simultaneously controlling real-time input and output of pictures. It was designed to provide a reliable picture processing system which would be cost-effective in the commercial production environment. Additional goals met by the system include flexibility and ease of operation and modification. PMID:21868923
Hamiltonian analysis of interacting fluids
NASA Astrophysics Data System (ADS)
Banerjee, Rabin; Ghosh, Subir; Mitra, Arpan Krishna
Ideal fluid dynamics is studied as a relativistic field theory with particular stress on its hamiltonian structure. The Schwinger condition, whose integrated version yields the stress tensor conservation, is explicitly verified both in equal-time and light-cone coordinate systems. We also consider the hamiltonian formulation of fluids interacting with an external gauge field. The complementary roles of the canonical (Noether) stress tensor and the symmetric one obtained by metric variation are discussed.
Rotor blade vortex interaction noise
NASA Astrophysics Data System (ADS)
Yu, Yung H.
Blade-vortex interaction noise-generated by helicopter main rotor blades is one of the most severe noise problems and is very important both in military applications and community acceptance of rotorcraft. Research over the decades has substantially improved physical understanding of noise-generating mechanisms, and various design concepts have been investigated to control noise radiation using advanced blade planform shapes and active blade control techniques. The important parameters to control rotor blade-vortex interaction noise and vibration have been identified: blade tip vortex structures and its trajectory, blade aeroelastic deformation, and airloads. Several blade tip design concepts have been investigated for diffusing tip vortices and also for reducing noise. However, these tip shapes have not been able to substantially reduce blade-vortex interaction noise without degradation of rotor performance. Meanwhile, blade root control techniques, such as higher-harmonic pitch control (HHC) and individual blade control (IBC) concepts, have been extensively investigated for noise and vibration reduction. The HHC technique has proved the substantial blade-vortex interaction noise reduction, up to 6 dB, while vibration and low-frequency noise have been increased. Tests with IBC techniques have shown the simultaneous reduction of rotor noise and vibratory loads with 2/rev pitch control inputs. Recently, active blade control concepts with smart structures have been investigated with the emphasis on active blade twist and trailing edge flap. Smart structures technologies are very promising, but further advancements are needed to meet all the requirements of rotorcraft applications in frequency, force, and displacement.
Clinical nutrition and drug interactions
Ekincioğlu, Aygin Bayraktar; Demirkan, Kutay
A drug's plasma level, pharmacological effects or side effects, elimination, physicochemical properties or stability could be changed by interactions of drug-drug or drug-nutrition products in patients who receive enteral or parenteral nutritional support. As a result, patients might experience ineffective outcomes or unexpected effects of therapy (such as drug toxicity, embolism). Stability or incompatibility problems between parenteral nutrition admixtures and drugs might lead to alterations in expected therapeutic responses from drug and/or parenteral nutrition, occlusion in venous catheter or symptoms or mortality due to infusion of composed particles. Compatibilities between parenteral nutrition and drugs are not always guaranteed in clinical practice. Although the list of compatibility or incompatibilities of drugs are published for the use of clinicians in their practices, factors such as composition of parenteral nutrition admixture, drug concentration, contact time in catheter, temperature of the environment and exposure to light could change the status of compatibilities between drugs and nutrition admixtures. There could be substantial clinical changes occurring in the patient's nutritional status and pharmacological effects of drugs due to interactions between enteral nutrition and drugs. Drug toxicity and ineffective nutritional support might occur as a result of those predictable interactions. Although administration of drugs via feeding tube is a complex and problematic route for drug usage, it is possible to minimise the risk of tube occlusion, decreased effects of drug and drug toxicity by using an appropriate technique. Therefore, it is important to consider pharmacological dosage forms of drugs while administering drugs via a feeding tube. In conclusion, since the pharmacists are well-experienced and more knowledgeable professionals in drugs and drug usage compared to other healthcare providers, it is suggested that provision of information
Interactive cutting path analysis programs
NASA Technical Reports Server (NTRS)
Weiner, J. M.; Williams, D. S.; Colley, S. R.
The operation of numerically controlled machine tools is interactively simulated. Four programs were developed to graphically display the cutting paths for a Monarch lathe, Cintimatic mill, Strippit sheet metal punch, and the wiring path for a Standard wire wrap machine. These programs are run on a IMLAC PDS-ID graphic display system under the DOS-3 disk operating system. The cutting path analysis programs accept input via both paper tape and disk file.
Polyelectrolytes and Their Biological Interactions
Katchalsky, A.
Polyelectrolytes are water-soluble electrically charged polymers. Their properties are determined by the interplay of the electrical forces, the Brownian motion of the macromolecular chain, and intermolecular Van der Waals forces. Charged polyacids or polybases are stretched by the electrostatic forces, as evidenced by increase in solution viscosity, or by the stretching of polyelectrolyte gels. The electrical field of the polyions is neutralized by a dense atmosphere of counter-ions. The counter-ion attraction to the polyions is expressed by a reduction of the osmotic activity of the polyion—the osmotic pressure being only 15 to 20 per cent of the ideal in highly charged polyelectrolytes neutralized by monovalent counter-ions, and as low as 1 to 3 per cent of the ideal for polyvalent counter-ions. Since the ionic atmosphere is only slightly dependent on added low molecular salt, the osmotic pressure of polyelectrolyte salt mixtures is approximately equal to the sum of the osmotic pressure of polyelectrolyte and salt alone. Acidic and basic polyelectrolytes interact electrostatically with precipitation at the point of polymeric electroneutrality. At higher salt concentrations the interaction is inhibited by the screening of polymeric fixed charges. The importance of these interactions in enzymatic processes is discussed. The electrical double layer is polarizable as may be deduced from dielectric and conductometric studies. The polarizability leads to strong dipole formation in an electrical field. These macromolecular dipoles may play a role in the adsorption of polyelectrolytes on charged surfaces. The final part of the paper is devoted to interactions of polyelectrolytes with cell membranes and the gluing of cells to higher aggregates by charged biocolloids. ImagesFigure 17Figure 18Figure 19Figure 20 PMID:14104085
Electrostatics interactions in classical simulations.
Cisneros, G Andrés; Babin, Volodymyr; Sagui, Celeste
Electrostatic interactions are crucial for both the accuracy and performance of atomistic biomolecular simulations. In this chapter we review well-established methods and current developments aiming at efficiency and accuracy. Specifically, we review the classical Ewald summations, particle-particle particle-method particle-method Ewald algorithms, multigrid, fast multipole, and local methods. We also highlight some recent developments targeting more accurate, yet classical, representation of the molecular charge distribution. PMID:23034752
Laser interaction with materials: introduction.
Phipps, Claude R; Zhigilei, Leonid; Polynkin, Pavel; Baumert, Thomas; Sarnet, Thierry; Bulgakova, Nadezhda; Bohn, Willy; Reif, Juergen
Laser-materials interaction is the fascinating nexus where laser physics, optical physics, and materials science intersect. Applications include microdeposition via laser-induced forward transfer of thin films, clean materials processing with femtosecond beams, creating color filters with nanoparticles, generating very high density storage sites on subpicosecond time scales, structuring solar cell surfaces for higher efficiency, making nanostructures that would be impossible by other means, and creating in-volume waveguiding structures using femtosecond laser filaments. PMID:25402939
Unlimited full configuration interaction calculations
NASA Astrophysics Data System (ADS)
Knowles, Peter J.; Handy, Nicholas C.
In very large full configuration interaction (full CI), nearly all of the CI coefficients are very small. Calculations, using a newly developed algorithm which exploits this fact, on NH3 with a DZP basis are reported, involving 2×108 Slater determinants. Such calculations are impossible with other existing full CI codes. The new algorithm opens up the opportunity of full CI calculations which are unlimited in size.
Cyclosporine and Herbal Supplement Interactions
Colombo, D.; Lunardon, L.; Bellia, G.
Cyclosporine (CyA) is a well-known immunosuppressant with a narrow therapeutic window. Its bioavailability is affected by many other traditional drugs and herbal extracts. Cytochrome P-450 isoenzymes CYP3A4 and CYP3A5 and protein P-glycoprotein (P-gp) are involved in CyA bioavailability. Interactions of CyA with herbal extracts are not well known, but, given their increased concomitant use, it is important to know which extracts, many of which are commonly self-prescribed, can affect CyA blood concentrations. Decreased CyA blood concentration has been shown with St John's wort in case reports and, in vivo animal studies, with ginger, liquorice, scutellariae radix, and quercetin. Increased CyA concentration has been reported in patients with grapefruit juice, chamomile, or berberine, and with cannabidiol or resveratrol in animal studies. Effects of Echinacea and Serenoa repens on CyA levels have not been shown consistently, but concomitant use should be avoided. Although findings from animal studies cannot be directly translated into humans, avoiding concomitant use of herbal extracts is prudent until human clinical studies have ruled out any possible interaction. Clinicians should interview their patients carefully about their use of herbal supplements before CyA administration, and those receiving CyA should be warned about possible interactions between herbal preparations and CyA. PMID:24527031
Laser interaction with pseudoblood clots
NASA Astrophysics Data System (ADS)
Paisley, Dennis L.; Stahl, David B.
In recent years lasers have become a common tool for medical procedures. Lasers are typically used to deliver energy/power to a biological specimen to alter its characteristics, fuse tissue or destroy a particular structure. Under a Los Alamos CRADA, we have been working with a medical laser company and a laser medical center to study the laser interaction with pseudo-blood clots that are typical of those found in human coronary arteries. A 577-nm flash lamp pumped dye laser beam is pulsed through a 300- micron optical fiber to deliver the laser energy on the surface of a pseudo-clot material. The fiber and pseudo-clot are surrounded by water or x-ray contrast fluid transparent at 577 and 514 nm. The laser-pulse/clot interaction creates a bubble at the water-clot interface. The bubble expands out and collapses back on the pseudo-clot resulting part of the clot being removed. Using a backlight technique with an electronic framing camera we record the bubble growth, expansion, and collapse, and the debris generated by the interaction.
Gauge interaction as periodicity modulation
NASA Astrophysics Data System (ADS)
Dolce, Donatello
The paper is devoted to a geometrical interpretation of gauge invariance in terms of the formalism of field theory in compact space-time dimensions (Dolce, 2011) [8]. In this formalism, the kinematic information of an interacting elementary particle is encoded on the relativistic geometrodynamics of the boundary of the theory through local transformations of the underlying space-time coordinates. Therefore gauge interactions are described as invariance of the theory under local deformations of the boundary. The resulting local variations of the field solution are interpreted as internal transformations. The internal symmetries of the gauge theory turn out to be related to corresponding space-time local symmetries. In the approximation of local infinitesimal isometric transformations, Maxwell's kinematics and gauge invariance are inferred directly from the variational principle. Furthermore we explicitly impose periodic conditions at the boundary of the theory as semi-classical quantization condition in order to investigate the quantum behavior of gauge interaction. In the abelian case the result is a remarkable formal correspondence with scalar QED.
Audiotactile interactions in temporal perception.
Occelli, Valeria; Spence, Charles; Zampini, Massimiliano
In the present review, we focus on how commonalities in the ontogenetic development of the auditory and tactile sensory systems may inform the interplay between these signals in the temporal domain. In particular, we describe the results of behavioral studies that have investigated temporal resolution (in temporal order, synchrony/asynchrony, and simultaneity judgment tasks), as well as temporal numerosity perception, and similarities in the perception of frequency across touch and hearing. The evidence reviewed here highlights features of audiotactile temporal perception that are distinctive from those seen for other pairings of sensory modalities. For instance, audiotactile interactions are characterized in certain tasks (e.g., temporal numerosity judgments) by a more balanced reciprocal influence than are other modality pairings. Moreover, relative spatial position plays a different role in the temporal order and temporal recalibration processes for audiotactile stimulus pairings than for other modality pairings. The effect exerted by both the spatial arrangement of stimuli and attention on temporal order judgments is described. Moreover, a number of audiotactile interactions occurring during sensory-motor synchronization are highlighted. We also look at the audiotactile perception of rhythm and how it may be affected by musical training. The differences emerging from this body of research highlight the need for more extensive investigation into audiotactile temporal interactions. We conclude with a brief overview of some of the key issues deserving of further research in this area. PMID:21400125
Meteoroid-bumper interactions program
NASA Technical Reports Server (NTRS)
Gough, P. S.
An investigation has been made of the interaction of meteoroids with shielded structures. The interaction has been simulated by the impact of Lexan cylinders onto lead shields in order to provide the vaporous debris believed to be created by meteoroid impact on a space vehicle. Shock compression data for Lexan was determined. This, in combination with the known shock compression data for the lead shield, has permitted the definition of the initial high pressure states in the impacted projectile and shield. The debris from such impact events has been permitted to interact with aluminum main walls. The walls were chosen to be sufficiently large to be effectively infinite in diameter compared to the loaded area. The thickness of the wall and the spacing from the shield were varied to determine the effect of these parameters. In addition, the effect of having a body of water behind the wall has been assessed. Measurements of the stagnation pressure in the debris cloud have been made and correlated with the response of the main wall.
Multiwave Interactions in Turbulent Jets
NASA Technical Reports Server (NTRS)
Mankbadi, Reda R.
Nonlinear wave-wave interactions in turbulent jets were investigated based on the integrated energy of each scale of motion in a cross section of the jet. The analysis indicates that two frequency components in the axisymmetric mode can interact with other background frequencies in the axisymmetric mode, thereby amplifying an enormous number of other frequencies. Two frequency components in a single helical mode cannot, by themselves, amplify other frequency components. But combinations of frequency components of helical and axisymmetric modes can amplify other frequencies in other helical modes. The present computations produce several features consistent with experimental observations such as: (1) dependency of the interactions on the initial phase differences, (2) enhancement of the momentum thickness under multifrequency forcing, and (3) the increase in background turbulence under forcing. In a multifrequency-excited jet, mixing enhancement was found to be a result of the turbulence enhancement rather than simply the amplification of forced wave components. The excitation waves pump energy from the mean flow to the turbulence, thus enhancing the latter. The high frequency waves enhance the turbulence close to the jet exit, but, the low frequency waves are most effective further downstream.
Interaction of factor XIII subunits.
Katona, Eva; Pénzes, Krisztina; Csapó, Andrea; Fazakas, Ferenc; Udvardy, Miklós L; Bagoly, Zsuzsa; Orosz, Zsuzsanna Z; Muszbek, László
Coagulation factor XIII (FXIII) is a heterotetramer consisting of 2 catalytic A subunits (FXIII-A2) and 2 protective/inhibitory B subunits (FXIII-B2). FXIII-B, a mosaic protein consisting of 10 sushi domains, significantly prolongs the lifespan of catalytic subunits in the circulation and prevents their slow progressive activation in plasmatic conditions. In this study, the biochemistry of the interaction between the 2 FXIII subunits was investigated. Using a surface plasmon resonance technique and an enzyme-linked immunosorbent assay-type binding assay, the equilibrium dissociation constant (Kd) for the interaction was established in the range of 10(-10) M. Based on the measured Kd, it was calculated that in plasma approximately 1% of FXIII-A2 should be in free form. This value was confirmed experimentally by measuring FXIII-A2 in plasma samples immunodepleted of FXIII-A2B2. Free plasma FXIII-A2 is functionally active, and when activated by thrombin and Ca(2+), it can cross-link fibrin. In cerebrospinal fluid and tears with much lower FXIII subunit concentrations, >80% of FXIII-A2 existed in free form. A monoclonal anti-FXIII-B antibody that prevented the interaction between the 2 subunits reacted with the recombinant combined first and second sushi domains of FXIII-B, and its epitope was localized to the peptide spanning positions 96 to 103 in the second sushi domain. PMID:24408323
NASA Astrophysics Data System (ADS)
Cheok, Adrian David
Cuteness in interactive systems is a relatively new development, yet having its roots in the aesthetics of many historical and cultural elements. Symbols of cuteness abound in nature as in the creatures of neotenous proportions; drawing in the care and concern of the parent and the care from a protector. We provide an in depth look at the role of cuteness in interactive systems beginning with a history. We particularly focus on the Japanese culture of Kawaii, which has made a large impact around the world, especially in entertainment, fashion, and animation. We then take the approach of defining cuteness in contemporary popular perception. User studies are presented offering an in-depth understanding of key perceptual elements which are identified as cute. This knowledge provides for the possibility to create a cute filter which can transform inputs and automatically create more cute outputs. The development of cute social computing and entertainment projects are discussed as well, providing an insight into the next generation of interactive systems which bring happiness and comfort to users of all ages and cultures through the soft power of cute.
Interacting epidemics on overlay networks
NASA Astrophysics Data System (ADS)
Funk, Sebastian; Jansen, Vincent A. A.
The interaction between multiple pathogens spreading on networks connecting a given set of nodes presents an ongoing theoretical challenge. Here, we aim to understand such interactions by studying bond percolation of two different processes on overlay networks of arbitrary joint degree distribution. We find that an outbreak of a first pathogen providing immunity to another one spreading subsequently on a second network connecting the same set of nodes does so most effectively if the degrees on the two networks are positively correlated. In that case, the protection is stronger the more heterogeneous the degree distributions of the two networks are. If, on the other hand, the degrees are uncorrelated or negatively correlated, increasing heterogeneity reduces the potential of the first process to prevent the second one from reaching epidemic proportions. We generalize these results to cases where the edges of the two networks overlap to arbitrary amount, or where the immunity granted is only partial. If both processes grant immunity to each other, we find a wide range of possible situations of coexistence or mutual exclusion, depending on the joint degree distribution of the underlying networks and the amount of immunity granted mutually. These results generalize the concept of a coexistence threshold and illustrate the impact of large-scale network structure on the interaction between multiple spreading agents.
Myxobacterial tools for social interactions
Pathak, Darshankumar T.; Wei, Xueming; Wall, Daniel
Myxobacteria exhibit complex social traits during which large populations of cells coordinate their behaviors. An iconic example is their response to starvation: thousands of cells move by gliding motility to build a fruiting body in which vegetative cells differentiate into spores. Here we review mechanisms that the model species Myxococcus xanthus uses for cell—cell interactions, with a focus on developmental signaling and social gliding motility. We also discuss a newly discovered cell—cell interaction whereby myxobacteria exchange their outer membrane (OM) proteins and lipids. The mechanism of OM transfer requires physical contact between aligned cells on a hard surface and is apparently mediated by OM fusion. The TraA and TraB proteins are required in both donor and recipient cells for transfer, suggesting bidirectional exchange, and TraA is thought to serve as a cell surface adhesin. OM exchange results in phenotypic changes that can alter gliding motility and development and is proposed to represent a novel microbial interacting platform to coordinate multicellular activities. PMID:23123306
Detonation interaction with an interface
NASA Astrophysics Data System (ADS)
Lieberman, D. H.; Shepherd, J. E.
Detonation interaction with an interface was investigated, where the interface separated a combustible from an oxidizing or inert mixture. The ethylene-oxygen combustible mixture had a fuel-rich composition to promote secondary combustion with the oxidizer in the turbulent mixing zone (TMZ) that resulted from the interaction. Sharp interfaces were created by using a nitro-cellulose membrane to separate the two mixtures. The membrane was mounted on a wood frame and inserted in the experimental test section at a 45° angle to the bulk flow direction. The membrane was destroyed by the detonation wave. The interaction resulted in a transmitted and reflected wave at a node point similar to regular shock refraction. A detonation refraction analysis was carried out to compare with the measured shock angles. It was observed that the measured angle is consistently lower than the predicted value. An uncertainty analysis revealed possible explanations for this systematic variation pointing to factors such as the incident wave curvature and the role of the nitro-cellulose diaphragm. Analysis of the TMZ and Mach stem formed from the reflection of the transmitted shock wave off the solid boundary were carried out and found to justify the size and strength of these features as a function of the test gas composition. The role of secondary combustion in the TMZ was also investigated and found to have a small influence on the wave structure.
Relatedness with different interaction configurations.
Taylor, Peter D; Grafen, A
In an inclusive fitness model of social behaviour, a key concept is that of the relatedness between two interactants. This is typically calculated with reference to a "focal" actor taken to be representative of all actors, but when there are different interaction configurations, relatedness must be constructed as an average over all such configurations. We provide an example of such a calculation in an island model with local reproduction but global mortality, leading to variable island size and hence variable numbers of individual interactions. We find that the analysis of this example significantly sharpens our understanding of relatedness. As an application, we obtain a version of Hamilton's rule for a tag-based model of altruism in a randomly mixed population. For large populations, the selective advantage of altruism is enhanced by low (but not too low) tag mutation rates and large numbers of tags. For moderate population sizes and moderate numbers of tags, we find a window of tag mutation rates with critical benefit/cost ratios of between 1 and 3. PMID:19833134
Plasma waves in parametric interactions
NASA Astrophysics Data System (ADS)
Yampolsky, Nikolai Andreevich
The nonlinear laser-plasma interaction is widely discussed in the modern plasma literature with applications to inertial confinement fusion, generation of fast electrons, and amplification of high power radiation. Among nonlinear wave phenomena in plasma, the parametric wave coupling often plays the dominant role in laser-plasma interaction at moderate laser intensities since it is the lowest order nonlinear effect. The plasma wave can mediate the parametric laser coupling with high efficiency. We study the interplay of the parametric laser-plasma interaction and other physical effects which may affect this interaction. We study this interplay with an emphasis on the plasma-based backward Raman amplifier (BRA) based on the three-wave coupling. Three major types of physical effects in the parametric wave coupling are studied. In the first part of the thesis, we find the longitudinal profiles of the interacting waves in cases of interest for pulse compression. We find the solution for the output pulse in backward Raman amplification seeded by a laser pulse of finite duration. We also propose a new scheme for high-power amplification for pulses in the terahertz frequency range. For this scheme, based on the four-wave mixing in a capillary filled with plasma, we find the profile of the output pulse. The second part of this thesis is devoted to transverse effects, which may reduce the focusability of the output pulse in backward Raman amplification. We find that the transverse modulations of the pump can be averaged and do not reduce the amplified pulse focusability if the longitudinal length of these modulations is much smaller than the amplification length. In the third part, we study the kinetic effects. We propose a simplified fluid model for the nonlinear Landau damping of a parametrically driven plasma wave and study the effect of nonlinear Landau damping in backward Raman amplification. This simplified model can be useful not only for understanding complex
Functional module identification in protein interaction networks by interaction patterns
Wang, Yijie; Qian, Xiaoning
Motivation: Identifying functional modules in protein–protein interaction (PPI) networks may shed light on cellular functional organization and thereafter underlying cellular mechanisms. Many existing module identification algorithms aim to detect densely connected groups of proteins as potential modules. However, based on this simple topological criterion of 'higher than expected connectivity', those algorithms may miss biologically meaningful modules of functional significance, in which proteins have similar interaction patterns to other proteins in networks but may not be densely connected to each other. A few blockmodel module identification algorithms have been proposed to address the problem but the lack of global optimum guarantee and the prohibitive computational complexity have been the bottleneck of their applications in real-world large-scale PPI networks. Results: In this article, we propose a novel optimization formulation LCP2 (low two-hop conductance sets) using the concept of Markov random walk on graphs, which enables simultaneous identification of both dense and sparse modules based on protein interaction patterns in given networks through searching for LCP2 by random walk. A spectral approximate algorithm SLCP2 is derived to identify non-overlapping functional modules. Based on a bottom-up greedy strategy, we further extend LCP2 to a new algorithm (greedy algorithm for LCP2) GLCP2 to identify overlapping functional modules. We compare SLCP2 and GLCP2 with a range of state-of-the-art algorithms on synthetic networks and real-world PPI networks. The performance evaluation based on several criteria with respect to protein complex prediction, high level Gene Ontology term prediction and especially sparse module detection, has demonstrated that our algorithms based on searching for LCP2 outperform all other compared algorithms. Availability and implementation: All data and code are available at http://www.cse.usf.edu/∼xqian/fmi/slcp2hop
Absolute negative mobility of interacting Brownian particles
NASA Astrophysics Data System (ADS)
Ou, Ya-li; Hu, Cai-tian; Wu, Jian-chun; Ai, Bao-quan
Transport of interacting Brownian particles in a periodic potential is investigated in the presence of an ac force and a dc force. From Brownian dynamic simulations, we find that both the interaction between particles and the thermal fluctuations play key roles in the absolute negative mobility (the particle noisily moves backwards against a small constant bias). When no the interaction acts, there is only one region where the absolute negative mobility occurs. In the presence of the interaction, the absolute negative mobility may appear in multiple regions. The weak interaction can be helpful for the absolute negative mobility, while the strong interaction has a destructive impact on it.
Solar wind interaction with planets --Abstract only
NASA Astrophysics Data System (ADS)
Michel, F. C.
The solar system displays a wide variety of solar wind interactions with the planets and satellites. The 'classic' interaction with the Earth's magnetoscope is just one special case which even now leaves important questions unanswered. We will touch on (1) the Earth's magnetospheric interaction and then go on to what are probably representative limiting cases. (2) the interaction with an unmagnetized object having no atmosphere (the Moon), (3) the interaction with unmagnetized objects having atmospheres (Mars and Venus), and (4) the interaction with bodies having so much plasma in their magnetospheres that they would probably generate winds of their own if not confined by the solar wind (Jupiter).
Drug interactions with grapefruit juice.
Ameer, B; Weintraub, R A
Some drugs demonstrate a significantly greater (up to 3-fold) mean oral bioavailability on coadministration with grapefruit juice. With some calcium antagonists, the benzodiazepines midazolam and triazolam and the antihistamine terfenadine, changes in bioavailability are accompanied by altered drug action. Study design factors possibly contribute to the magnitude of changes in drug bioavailability; they include the source of the citrus, its intake schedule, drug formulations and individual metabolising capacity. The components of citrus juice that are responsible for clinical drug interactions have yet to be fully determined. Based on the flavonoid naringin's unique distribution in the plant kingdom, abundance in grapefruit and ability to inhibit metabolic enzymes, naringin is likely to be one of the grapefruit components influencing drug metabolism. Other components present in citrus fruit, such as furanocoumarins, may be more potent inhibitors than flavonoids and are under investigation. Conclusions drawn from clinical drug interaction studies should be considered specific to the citrus fruit products evaluated because of the variation in their natural product content. The predominant mechanism for enhanced bioavailability is presumably the inhibition of oxidative drug metabolism in the small intestine. The consistent findings across studies of diverse cytochrome P450 (CYP) 3A substrates support the mechanistic hypothesis that 1 or more grapefruit juice components inhibit CYP3A enzymes in the gastrointestinal tract. The evaluation of the need to avoid the concomitant intake of grapefruit products with drugs is best done on an individual drug basis rather than collectively by drug class. Based on the narrow therapeutic range of cyclosporin and research experience in organ transplant recipients, its interaction with grapefruit juice is likely to be clinically significant. PMID:9260034
Interactive 3D Mars Visualization
NASA Technical Reports Server (NTRS)
Powell, Mark W.
The Interactive 3D Mars Visualization system provides high-performance, immersive visualization of satellite and surface vehicle imagery of Mars. The software can be used in mission operations to provide the most accurate position information for the Mars rovers to date. When integrated into the mission data pipeline, this system allows mission planners to view the location of the rover on Mars to 0.01-meter accuracy with respect to satellite imagery, with dynamic updates to incorporate the latest position information. Given this information so early in the planning process, rover drivers are able to plan more accurate drive activities for the rover than ever before, increasing the execution of science activities significantly. Scientifically, this 3D mapping information puts all of the science analyses to date into geologic context on a daily basis instead of weeks or months, as was the norm prior to this contribution. This allows the science planners to judge the efficacy of their previously executed science observations much more efficiently, and achieve greater science return as a result. The Interactive 3D Mars surface view is a Mars terrain browsing software interface that encompasses the entire region of exploration for a Mars surface exploration mission. The view is interactive, allowing the user to pan in any direction by clicking and dragging, or to zoom in or out by scrolling the mouse or touchpad. This set currently includes tools for selecting a point of interest, and a ruler tool for displaying the distance between and positions of two points of interest. The mapping information can be harvested and shared through ubiquitous online mapping tools like Google Mars, NASA WorldWind, and Worldwide Telescope.