1,619 research outputs found

    Driven vortices in 3D layered superconductors: Dynamical ordering along the c-axis

    Full text link
    We study a 3D model of driven vortices in weakly coupled layered superconductors with strong pinning. Above the critical force FcF_c, we find a plastic flow regime in which pancakes in different layers are uncoupled, corresponding to a pancake gas. At a higher FF, there is an ``smectic flow'' regime with short-range interlayer order, corresponding to an entangled line liquid. Later, the transverse displacements freeze and vortices become correlated along the c-axis, resulting in a transverse solid. Finally, at a force FsF_s the longitudinal displacements freeze and we find a coherent solid of rigid lines.Comment: 4 pages, 3 postscript figure

    Knowledge, Attitudes, and Commitment Concerning Evidence-Based Prevention Programs: Differences Between Family and Consumer Sciences and 4-H Youth Development Educators

    Get PDF
    We describe the results of a study designed to assess knowledge, perceptions, and attitudes towards evidence-based and other prevention programs among county Extension educators. We examined differences across educators from Family and Consumer Sciences (FCS) and 4-H Youth Development. Analyses based on a multi-state sample of educators revealed significant differences such that, compared to their 4-H counterparts, FCS educators were more knowledgeable of evidence-based programs and had more favorable perceptions and attitudes towards evidence-based and other pre-packaged prevention programs. These findings suggest that Extension administrators should work to encourage the use of evidence-based and other prevention programs, particularly within 4-H

    Development of the Adherence Predictive Index (API) for Medication Taking

    Get PDF
    The objective for this study was to explore if characteristics of personality type using the Preferred Communication Style Questionnaire, in concert with the demographic characteristics of age, education, and race/ethnicity, are associated with, and help predict, individuals’ medication adherence behavior. Data were collected via an on-line survey, sent to a sample of adults residing in the United States, between April 28 and June 22, 2015. Out of 26,173 responses to the survey, 16,736 reported taking one or more medications and were eligible for inclusion in this study. The development of the Adherence Predictive Index (API) used mean Morisky Medication Adherence Scale (MMAS-8) scores for each of eight personality types as a starting point. API scores were calculated by adding or subtracting specific values to each group’s mean MMAS-8 score based on personality type, age, education and race/ethnicity characteristics which were demonstrated to have significant effects on adherence. The weighting system was informed by linear regression, logistic regression, personality type literature, researcher experience, and previous qualitative and quantitative research. The resultant score was converted to an API score that ranged from 1 to 5 so that it would be feasible for health care providers to understand and use. The findings showed that an Adherence Predictive Index (API) could be developed based upon a relatively small number of questions that focus on personality type and generational, educational, and cultural experiences. It was developed in order to be a component of a comprehensive program that has the goals of (1) identifying and describing specific behavioral strategies individuals are most likely to successfully employ, (2) motivating patients by using their preferred communication style, and (3) predicting each patient’s propensity to adhere. Future research is needed to evaluate the index’s validity, sensitivity, and effectiveness in actual practice compared with other risk indices

    Development of the Adherence Predictive Index (API) for Medication Taking

    Get PDF
    The objective for this study was to explore if characteristics of personality type using the Preferred Communication Style Questionnaire, in concert with the demographic characteristics of age, education, and race/ethnicity, are associated with, and help predict, individuals’ medication adherence behavior. Data were collected via an on-line survey, sent to a sample of adults residing in the United States, between April 28 and June 22, 2015. Out of 26,173 responses to the survey, 16,736 reported taking one or more medications and were eligible for inclusion in this study. The development of the Adherence Predictive Index (API) used mean Morisky Medication Adherence Scale (MMAS-8) scores for each of eight personality types as a starting point. API scores were calculated by adding or subtracting specific values to each group’s mean MMAS-8 score based on personality type, age, education and race/ethnicity characteristics which were demonstrated to have significant effects on adherence. The weighting system was informed by linear regression, logistic regression, personality type literature, researcher experience, and previous qualitative and quantitative research. The resultant score was converted to an API score that ranged from 1 to 5 so that it would be feasible for health care providers to understand and use. The findings showed that an Adherence Predictive Index (API) could be developed based upon a relatively small number of questions that focus on personality type and generational, educational, and cultural experiences. It was developed in order to be a component of a comprehensive program that has the goals of (1) identifying and describing specific behavioral strategies individuals are most likely to successfully employ, (2) motivating patients by using their preferred communication style, and (3) predicting each patient’s propensity to adhere. Future research is needed to evaluate the index’s validity, sensitivity, and effectiveness in actual practice compared with other risk indices.   Type: Original Researc

    Hall noise and transverse freezing in driven vortex lattices

    Full text link
    We study driven vortices lattices in superconducting thin films. Above the critical force FcF_c we find two dynamical phase transitions at FpF_p and FtF_t, which could be observed in simultaneous noise measurements of the longitudinal and the Hall voltage. At FpF_p there is a transition from plastic flow to smectic flow where the voltage noise is isotropic (Hall noise = longitudinal noise) and there is a peak in the differential resistance. At FtF_t there is a sharp transition to a frozen transverse solid where the Hall noise falls down abruptly and vortex motion is localized in the transverse direction.Comment: 4 pages, 3 figure

    Prevention of Over-Pressurization During Combustion in a Sealed Chamber

    Get PDF
    The combustion of flammable material in a sealed chamber invariably leads to an initial pressure rise in the volume. The pressure rise is due to the increase in the total number of gaseous moles (condensed fuel plus chamber oxygen combining to form gaseous carbon dioxide and water vapor) and, most importantly, the temperature rise of the gas in the chamber. Though the rise in temperature and pressure would reduce with time after flame extinguishment due to the absorption of heat by the walls and contents of the sealed spacecraft, the initial pressure rise from a fire, if large enough, could lead to a vehicle over-pressure and the release of gas through the pressure relief valve. This paper presents a simple lumped-parameter model of the pressure rise in a sealed chamber resulting from the heat release during combustion. The transient model considers the increase in gaseous moles due to combustion, and heat transfer to the chamber walls by convection and radiation and to the fuel-sample holder by conduction, as a function of the burning rate of the material. The results of the model are compared to the pressure rise in an experimental chamber during flame spread tests as well as to the pressure falloff after flame extinguishment. The experiments involve flame spread over thin solid fuel samples. Estimates of the heat release rate profiles for input to the model come from the assumed stoichiometric burning of the fuel along with the observed flame spread behavior. The sensitivity of the model to predict maximum chamber pressure is determined with respect to the uncertainties in input parameters. Model predictions are also presented for the pressure profile anticipated in the Fire Safety-1 experiment, a material flammability and fire safety experiment proposed for the European Space Agency (ESA) Automated Transfer Vehicle (ATV). Computations are done for a range of scenarios including various initial pressures and sample sizes. Based on these results, various mitigation approaches are suggested to prevent vehicle over-pressurization and help guide the definition of the space experiment

    Langevin simulations of the out-of-equilibrium dynamics of the vortex glass in high-temperature superconductors

    Full text link
    We study the relaxation dynamics of flux lines in dirty high-temperature superconductors using numerical simulations of a London-Langevin model of the interacting vortex lines. By analysing the equilibrium dynamics in the vortex liquid phase we find a dynamic crossover to a glassy non-equilibrium regime. We then focus on the out-of-equilibrium dynamics of the vortex glass phase using tools that are common in the study of other glassy systems. By monitoring the two-times roughness and dynamic wandering we identify and characterize finite-size effects that are similar, though more complex, than the ones found in the stationary roughness of clean interface dynamics. The two-times density-density correlation and mean-squared-displacement correlation age and their temporal scaling follows a multiplicative law similar to the one found at criticality. The linear responses also age and the comparison with their associated correlations shows that the equilibrium fluctuation-dissipation relation is modified in a simple manner that allows for the identification of an effective temperature characterizing the dynamics of the slow modes. The effective temperature is closely related to the vortex liquid-vortex glass crossover temperature. Interestingly enough, our study demonstrates that the glassy dynamics in the vortex glass is basically identical to the one of a single elastic line in a disordered environment (with the same type of scaling though with different parameters). Possible extensions and the experimental relevance of these results are also discussed.Comment: 22 pages, 29 figure

    Structure of the lectin mannose 6-phosphate receptor homology (MRH) domain of glucosidase II an enzyme that regulates glycoprotein folding quality control in the endoplasmic reticulum

    Get PDF
    Here we report for the first time the three-dimensional structure of a mannose 6-phosphate receptor homology (MRH) domain present in a protein with enzymatic activity, glucosidase II (GII). GII is involved in glycoprotein folding in the endoplasmic reticulum. GII removes the two innermost glucose residues from the Glc3Man9GlcNAc2 transferred to nascent proteins and the glucose added by UDP-Glc:glycoprotein glucosyltransferase. GII is composed of a catalytic GIIα subunit and a regulatory GIIβ subunit. GIIβ participates in the endoplasmic reticulum localization of GIIα and mediates in vivo enhancement of N-glycan trimming by GII through its C-terminal MRH domain. We determined the structure of a functional GIIβ MRH domain by NMR spectroscopy. It adopts a β-barrel fold similar to that of other MRH domains, but its binding pocket is the most shallow known to date as it accommodates a single mannose residue. In addition, we identified a conserved residue outside the binding pocket (Trp-409) present in GIIβ but not in other MRHs that influences GII glucose trimming activity.Fil: Olson, Linda J.. Medical College Of Wisconsin; Estados UnidosFil: Orsi, Ramiro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Alculumbre, Solana G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Peterson, Francis C.. Medical College Of Wisconsin; Estados UnidosFil: Stigliano, Ivan Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Parodi, Armando Jose A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: D'alessio, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Universidad de Buenos Aires; ArgentinaFil: Dahms, Nancy M.. Medical College Of Wisconsin; Estados Unido

    Semi-Classical Description of Antiproton Capture on Atomic Helium

    Full text link
    A semi-classical, many-body atomic model incorporating a momentum-dependent Heisenberg core to stabilize atomic electrons is used to study antiproton capture on Helium. Details of the antiproton collisions leading to eventual capture are presented, including the energy and angular momentum states of incident antiprotons which result in capture via single or double electron ionization, i.e. into [He++ pˉ^{++}\,\bar p or He+ pˉ^{+}\,\bar p], and the distribution of energy and angular momentum states following the Auger cascade. These final states are discussed in light of recently reported, anomalously long-lived antiproton states observed in liquid He.Comment: 15 pages, 9 figures may be obtained from authors, Revte
    • …
    corecore