Self-Rated Health among Adult Women of Mexican Origin

ERIC Educational Resources Information Center

Wilkinson, Anna V.; Hernandez-Valero, Maria A.; Etzel, Carol J.; Barcenas, Carlos H.; Spitz, Margaret R.; Bondy, Melissa L.; Strom, Sara S.

2006-01-01

Self-rated health (SRH), a consistent predictor of mortality among diverse populations, is sensitive to health indicators and social factors. American-born Hispanics report better SRH than their foreign-born counterparts but simultaneously report poorer health indicators and have shorter life expectancy. Using a matched prospective cross-sectional…

Extended Lagrangian Excited State Molecular Dynamics.

PubMed

Bjorgaard, J A; Sheppard, D; Tretiak, S; Niklasson, A M N

2018-02-13

An extended Lagrangian framework for excited state molecular dynamics (XL-ESMD) using time-dependent self-consistent field theory is proposed. The formulation is a generalization of the extended Lagrangian formulations for ground state Born-Oppenheimer molecular dynamics [Phys. Rev. Lett. 2008 100, 123004]. The theory is implemented, demonstrated, and evaluated using a time-dependent semiempirical model, though it should be generally applicable to ab initio theory. The simulations show enhanced energy stability and a significantly reduced computational cost associated with the iterative solutions of both the ground state and the electronically excited states. Relaxed convergence criteria can therefore be used both for the self-consistent ground state optimization and for the iterative subspace diagonalization of the random phase approximation matrix used to calculate the excited state transitions. The XL-ESMD approach is expected to enable numerically efficient excited state molecular dynamics for such methods as time-dependent Hartree-Fock (TD-HF), Configuration Interactions Singles (CIS), and time-dependent density functional theory (TD-DFT).

Comparison of junctionless and inversion-mode p-type metal-oxide-semiconductor field-effect transistors in presence of hole-phonon interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dib, E., E-mail: elias.dib@for.unipi.it; Carrillo-Nuñez, H.; Cavassilas, N.

Junctionless transistors are being considered as one of the alternatives to conventional metal-oxide field-effect transistors. In this work, it is then presented a simulation study of silicon double-gated p-type junctionless transistors compared with its inversion-mode counterpart. The quantum transport problem is solved within the non-equilibrium Green's function formalism, whereas hole-phonon interactions are tackled by means of the self-consistent Born approximation. Our findings show that junctionless transistors should perform as good as a conventional transistor only for ultra-thin channels, with the disadvantage of requiring higher supply voltages in thicker channel configurations.

Dynamic Structure Factor: An Introduction

NASA Astrophysics Data System (ADS)

Sturm, K.

1993-02-01

The doubly differential cross-section for weak inelastic scattering of waves or particles by manybody systems is derived in Born approximation and expressed in terms of the dynamic structure factor according to van Hove. The application of this very general scheme to scattering of neutrons, x-rays and high-energy electrons is discussed briefly. The dynamic structure factor, which is the space and time Fourier transform of the density-density correlation function, is a property of the many-body system independent of the external probe and carries information on the excitation spectrum of the system. The relation of the electronic structure factor to the density-density response function defined in linear-response theory is shown using the fluctuation-dissipation theorem. This is important for calculations, since the response function can be calculated approximately from the independent-particle response function in self-consistent field approximations, such as the random-phase approximation or the local-density approximation of the density functional theory. Since the density-density response function also determines the dielectric function, the dynamic structure can be expressed by the dielectric function.

Prematurity and parental self-efficacy: the Preterm Parenting & Self-Efficacy Checklist.

PubMed

Pennell, Claire; Whittingham, Koa; Boyd, Roslyn; Sanders, Matthew; Colditz, Paul

2012-12-01

There is a lack of research investigating parental self-efficacy in parents of infants born preterm as well as a paucity of parental self-efficacy measures that are domain-specific and theoretically grounded. This study aimed to compare parental self-efficacy in parents of infants born term, preterm and very preterm as well as to test whether parental self-efficacy mediates the relationship between psychological symptoms and parental competence. In order to achieve this, a new measure of parental self-efficacy and parental competence relevant for the preterm population and consistent with Bandura's (1977, 1986, 1989) conceptualisation of self-efficacy was developed. Participants included 155 parents, 83 of whom were parents of very preterm (GA<32 weeks), 40 parents of preterm (GA<37 weeks) and 32 parents of term born infants. Parents completed the Preterm Parenting & Self-Efficacy Checklist (the new measure), Family Demographic Questionnaire, Depression Anxiety Stress Scale and Self-Efficacy Questionnaire. This initial study indicates that the Preterm Parenting & Self-Efficacy Checklist has adequate content validity, construct validity, internal consistency and split half reliability. Contrary to expectations, parents of very preterm infants did not report significantly lower overall levels of parental self-efficacy or significantly higher levels of psychological symptoms compared to parents of preterm and term infants. Parental self-efficacy about parenting tasks mediated the relationship between psychological symptoms and self perceived parental competence as predicted. Clinical implications of the results and suggestions for future research are discussed. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

Reduced-Density-Matrix Description of Decoherence and Relaxation Processes for Electron-Spin Systems

NASA Astrophysics Data System (ADS)

Jacobs, Verne

2017-04-01

Electron-spin systems are investigated using a reduced-density-matrix description. Applications of interest include trapped atomic systems in optical lattices, semiconductor quantum dots, and vacancy defect centers in solids. Complimentary time-domain (equation-of-motion) and frequency-domain (resolvent-operator) formulations are self-consistently developed. The general non-perturbative and non-Markovian formulations provide a fundamental framework for systematic evaluations of corrections to the standard Born (lowest-order-perturbation) and Markov (short-memory-time) approximations. Particular attention is given to decoherence and relaxation processes, as well as spectral-line broadening phenomena, that are induced by interactions with photons, phonons, nuclear spins, and external electric and magnetic fields. These processes are treated either as coherent interactions or as environmental interactions. The environmental interactions are incorporated by means of the general expressions derived for the time-domain and frequency-domain Liouville-space self-energy operators, for which the tetradic-matrix elements are explicitly evaluated in the diagonal-resolvent, lowest-order, and Markov (short-memory time) approximations. Work supported by the Office of Naval Research through the Basic Research Program at The Naval Research Laboratory.

Modeling of phonon scattering in n-type nanowire transistors using one-shot analytic continuation technique

NASA Astrophysics Data System (ADS)

Bescond, Marc; Li, Changsheng; Mera, Hector; Cavassilas, Nicolas; Lannoo, Michel

2013-10-01

We present a one-shot current-conserving approach to model the influence of electron-phonon scattering in nano-transistors using the non-equilibrium Green's function formalism. The approach is based on the lowest order approximation (LOA) to the current and its simplest analytic continuation (LOA+AC). By means of a scaling argument, we show how both LOA and LOA+AC can be easily obtained from the first iteration of the usual self-consistent Born approximation (SCBA) algorithm. Both LOA and LOA+AC are then applied to model n-type silicon nanowire field-effect-transistors and are compared to SCBA current characteristics. In this system, the LOA fails to describe electron-phonon scattering, mainly because of the interactions with acoustic phonons at the band edges. In contrast, the LOA+AC still well approximates the SCBA current characteristics, thus demonstrating the power of analytic continuation techniques. The limits of validity of LOA+AC are also discussed, and more sophisticated and general analytic continuation techniques are suggested for more demanding cases.

Electrostatics of proteins in dielectric solvent continua. I. An accurate and efficient reaction field description

NASA Astrophysics Data System (ADS)

Bauer, Sebastian; Mathias, Gerald; Tavan, Paul

2014-03-01

We present a reaction field (RF) method which accurately solves the Poisson equation for proteins embedded in dielectric solvent continua at a computational effort comparable to that of an electrostatics calculation with polarizable molecular mechanics (MM) force fields. The method combines an approach originally suggested by Egwolf and Tavan [J. Chem. Phys. 118, 2039 (2003)] with concepts generalizing the Born solution [Z. Phys. 1, 45 (1920)] for a solvated ion. First, we derive an exact representation according to which the sources of the RF potential and energy are inducible atomic anti-polarization densities and atomic shielding charge distributions. Modeling these atomic densities by Gaussians leads to an approximate representation. Here, the strengths of the Gaussian shielding charge distributions are directly given in terms of the static partial charges as defined, e.g., by standard MM force fields for the various atom types, whereas the strengths of the Gaussian anti-polarization densities are calculated by a self-consistency iteration. The atomic volumes are also described by Gaussians. To account for covalently overlapping atoms, their effective volumes are calculated by another self-consistency procedure, which guarantees that the dielectric function ɛ(r) is close to one everywhere inside the protein. The Gaussian widths σi of the atoms i are parameters of the RF approximation. The remarkable accuracy of the method is demonstrated by comparison with Kirkwood's analytical solution for a spherical protein [J. Chem. Phys. 2, 351 (1934)] and with computationally expensive grid-based numerical solutions for simple model systems in dielectric continua including a di-peptide (Ac-Ala-NHMe) as modeled by a standard MM force field. The latter example shows how weakly the RF conformational free energy landscape depends on the parameters σi. A summarizing discussion highlights the achievements of the new theory and of its approximate solution particularly by comparison with so-called generalized Born methods. A follow-up paper describes how the method enables Hamiltonian, efficient, and accurate MM molecular dynamics simulations of proteins in dielectric solvent continua.

Electrostatics of proteins in dielectric solvent continua. I. An accurate and efficient reaction field description.

PubMed

Bauer, Sebastian; Mathias, Gerald; Tavan, Paul

2014-03-14

We present a reaction field (RF) method which accurately solves the Poisson equation for proteins embedded in dielectric solvent continua at a computational effort comparable to that of an electrostatics calculation with polarizable molecular mechanics (MM) force fields. The method combines an approach originally suggested by Egwolf and Tavan [J. Chem. Phys. 118, 2039 (2003)] with concepts generalizing the Born solution [Z. Phys. 1, 45 (1920)] for a solvated ion. First, we derive an exact representation according to which the sources of the RF potential and energy are inducible atomic anti-polarization densities and atomic shielding charge distributions. Modeling these atomic densities by Gaussians leads to an approximate representation. Here, the strengths of the Gaussian shielding charge distributions are directly given in terms of the static partial charges as defined, e.g., by standard MM force fields for the various atom types, whereas the strengths of the Gaussian anti-polarization densities are calculated by a self-consistency iteration. The atomic volumes are also described by Gaussians. To account for covalently overlapping atoms, their effective volumes are calculated by another self-consistency procedure, which guarantees that the dielectric function ε(r) is close to one everywhere inside the protein. The Gaussian widths σ(i) of the atoms i are parameters of the RF approximation. The remarkable accuracy of the method is demonstrated by comparison with Kirkwood's analytical solution for a spherical protein [J. Chem. Phys. 2, 351 (1934)] and with computationally expensive grid-based numerical solutions for simple model systems in dielectric continua including a di-peptide (Ac-Ala-NHMe) as modeled by a standard MM force field. The latter example shows how weakly the RF conformational free energy landscape depends on the parameters σ(i). A summarizing discussion highlights the achievements of the new theory and of its approximate solution particularly by comparison with so-called generalized Born methods. A follow-up paper describes how the method enables Hamiltonian, efficient, and accurate MM molecular dynamics simulations of proteins in dielectric solvent continua.

Using vignettes to rethink Latino-white disparities in self-rated health

PubMed Central

Bzostek, Sharon; Sastry, Narayan; Goldman, Noreen; Pebley, Anne; Duffy, Denise

2016-01-01

Researchers often rely on respondents’ self-rated health (SRH) to measure social disparities in health, but recent studies suggest that systematically different reporting styles across groups can yield misleading conclusions about disparities in SRH. In this study, we test whether this finding extends to ethnic differences in self-assessments of health in particular domains. We document differences between US-born whites and four Latino subgroups in respondents’ assessments of health in six health domains using data from the second wave of the Los Angeles Family and Neighborhood Study (N=1468). We use both conventional methods and an approach that uses vignettes to adjust for differential reporting styles. Our results suggest that despite consistent evidence from the literature that Latinos tend to rate their overall health more poorly than whites, and that Latino immigrants report worse SRH than US-born Latinos, this pattern is not true of self-reports in individual health domains. We find that at the bivariate level, US-born whites (and often US-born Mexicans) have significantly more pessimistic reporting styles than Latino immigrants. After adding controls, we find evidence of significantly different reporting styles for only one domain: US-born Mexicans and whites consistently interpret head pain more severely than the other Latino subgroups. Finally, we find that both before and after adjusting for differences in rating styles across groups, non-Mexican Latino immigrants report better social and physical functioning and less pain than other groups. Our findings underscore the advantages of domain-specific ratings when evaluating ethnic differences in self-assessments of health. We encourage researchers studying social disparities in health to consider respondents’ self-assessments in a variety of domains, and to also investigate (when possible) potential biases in their findings due to different reporting styles. The anchoring vignettes approach we use is one potential method for overcoming biases due to different rating styles across groups. PMID:26706402

Full self-consistency versus quasiparticle self-consistency in diagrammatic approaches: Exactly solvable two-site Hubbard model

DOE PAGES

Kutepov, A. L.

2015-07-22

Self-consistent solutions of Hedin's equations (HE) for the two-site Hubbard model (HM) have been studied. They have been found for three-point vertices of increasing complexity (Γ = 1 (GW approximation), Γ₁ from the first-order perturbation theory, and the exact vertex Γ E). Comparison is made between the cases when an additional quasiparticle (QP) approximation for Green's functions is applied during the self-consistent iterative solving of HE and when QP approximation is not applied. Results obtained with the exact vertex are directly related to the present open question—which approximation is more advantageous for future implementations, GW + DMFT or QPGW +more » DMFT. It is shown that in a regime of strong correlations only the originally proposed GW + DMFT scheme is able to provide reliable results. Vertex corrections based on Perturbation Theory systematically improve the GW results when full self-consistency is applied. The application of QP self-consistency combined with PT vertex corrections shows similar problems to the case when the exact vertex is applied combined with QP sc. An analysis of Ward Identity violation is performed for all studied in this work's approximations and its relation to the general accuracy of the schemes used is provided.« less

Full self-consistency versus quasiparticle self-consistency in diagrammatic approaches: exactly solvable two-site Hubbard model.

PubMed

Kutepov, A L

2015-08-12

Self-consistent solutions of Hedin's equations (HE) for the two-site Hubbard model (HM) have been studied. They have been found for three-point vertices of increasing complexity (Γ = 1 (GW approximation), Γ1 from the first-order perturbation theory, and the exact vertex Γ(E)). Comparison is made between the cases when an additional quasiparticle (QP) approximation for Green's functions is applied during the self-consistent iterative solving of HE and when QP approximation is not applied. The results obtained with the exact vertex are directly related to the present open question-which approximation is more advantageous for future implementations, GW + DMFT or QPGW + DMFT. It is shown that in a regime of strong correlations only the originally proposed GW + DMFT scheme is able to provide reliable results. Vertex corrections based on perturbation theory (PT) systematically improve the GW results when full self-consistency is applied. The application of QP self-consistency combined with PT vertex corrections shows similar problems to the case when the exact vertex is applied combined with QP sc. An analysis of Ward Identity violation is performed for all studied in this work's approximations and its relation to the general accuracy of the schemes used is provided.

Does the development of executive functioning in infants born preterm benefit from maternal directiveness?

PubMed

van de Weijer-Bergsma, Eva; Wijnroks, Lex; van Haastert, Ingrid C; Boom, Jan; Jongmans, Marian J

2016-12-01

Problems in early development of executive functioning may underlie the vulnerability and individual variability of infants born preterm for behavioral and learning problems. Parenting behaviors may aggravate or temper this increased risk for dysfunction. This study assessed how maternal parenting behaviors predict individual differences in early development of executive functioning in infants born preterm, and whether this varies with infant temperament, i.e., self-regulation. Participants were 76 infants born preterm (≤36weeks' gestation and <2500g birth weight) and their mothers. Maternal sensitive responsiveness and directiveness were observed during a mother-infant interaction situation at 7, 10 and 14months corrected age. At the same ages, executive functioning was measured using the A-not-B task. An infant self-regulation questionnaire (IBQ-R) was completed by mothers at 7months. After controlling for perinatal risk factors, Multivariate Latent Growth Modeling showed that consistently higher levels of maternal directiveness predicted a stronger increase in A-not-B performance, which did not vary with infant self-regulation. No relationship between maternal sensitive responsiveness and development in A-not-B performance in infants born preterm was found. These results suggest that preterm infants' early executive functioning development in the first year of life may benefit from a more and consistent directive approach by their mothers. These findings have important implications for early intervention programs aimed at facilitating preterm infants' development. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Thermal transport through a spin-phonon interacting junction: A nonequilibrium Green's function method study

NASA Astrophysics Data System (ADS)

Zhang, Zu-Quan; Lü, Jing-Tao

2017-09-01

Using the nonequilibrium Green's function method, we consider heat transport in an insulating ferromagnetic spin chain model with spin-phonon interaction under an external magnetic field. Employing the Holstein-Primakoff transformation to the spin system, we treat the resulted magnon-phonon interaction within the self-consistent Born approximation. We find the magnon-phonon coupling can change qualitatively the magnon thermal conductance in the high-temperature regime. At a spectral mismatched ferromagnetic-normal insulator interface, we also find thermal rectification and negative differential thermal conductance due to the magnon-phonon interaction. We show that these effects can be effectively tuned by the external applied magnetic field, a convenient advantage absent in anharmonic phonon and electron-phonon systems studied before.

CMB-lensing beyond the Born approximation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marozzi, Giovanni; Fanizza, Giuseppe; Durrer, Ruth

2016-09-01

We investigate the weak lensing corrections to the cosmic microwave background temperature anisotropies considering effects beyond the Born approximation. To this aim, we use the small deflection angle approximation, to connect the lensed and unlensed power spectra, via expressions for the deflection angles up to third order in the gravitational potential. While the small deflection angle approximation has the drawback to be reliable only for multipoles ℓ ∼< 2500, it allows us to consistently take into account the non-Gaussian nature of cosmological perturbation theory beyond the linear level. The contribution to the lensed temperature power spectrum coming from the non-Gaussianmore » nature of the deflection angle at higher order is a new effect which has not been taken into account in the literature so far. It turns out to be the leading contribution among the post-Born lensing corrections. On the other hand, the effect is smaller than corrections coming from non-linearities in the matter power spectrum, and its imprint on CMB lensing is too small to be seen in present experiments.« less

Self-confidence in financial analysis: a study of younger and older male professional analysts.

PubMed

Webster, R L; Ellis, T S

2001-06-01

Measures of reported self-confidence in performing financial analysis by 59 professional male analysts, 31 born between 1946 and 1964 and 28 born between 1965 and 1976, were investigated and reported. Self-confidence in one's ability is important in the securities industry because it affects recommendations and decisions to buy, sell, and hold securities. The respondents analyzed a set of multiyear corporate financial statements and reported their self-confidence in six separate financial areas. Data from the 59 male financial analysts were tallied and analyzed using both univariate and multivariate statistical tests. Rated self-confidence was not significantly different for the younger and the older men. These results are not consistent with a similar prior study of female analysts in which younger women showed significantly higher self-confidence than older women.

Phonon assisted carrier motion on the Wannier-Stark ladder

NASA Astrophysics Data System (ADS)

Cheung, Alfred; Berciu, Mona

2014-03-01

It is well known that at zero temperature and in the absence of electron-phonon coupling, the presence of an electric field leads to localization of carriers residing in a single band of finite bandwidth. In this talk, we will present an implementation of the self-consistent Born approximation (SCBA) to study the effect of weak electron-phonon coupling on the motion of a carrier in a biased system. At moderate and strong electron-phonon coupling, we supplement the SCBA, describing the string of phonons left behind by the carrier, with the momentum average approximation to describe the phonon cloud that accompanies the resulting polaron. We find that coupling to the lattice delocalizes the carrier, as expected, although long-lived resonances resulting from the Wannier-Stark states of the polaron may appear in certain regions of the parameter space. We end with a discussion of how our method can be improved to model disorder, other types of electron-phonon coupling, and electron-hole pair dissociation in a biased system.

Religiosity and Utilization of Complementary and Alternative Medicine among Foreign-Born Hispanics in the United States

ERIC Educational Resources Information Center

Heathcote, John D.; West, Joshua H.; Hall, P. Cougar; Trinidad, Dennis R.

2011-01-01

The purpose of this study was to test the association between religiosity and utilization of complementary and alternative medicine (CAM) in a sample of foreign-born Hispanic adults, even when excluding prayer as a form of CAM. Data were collected using a self-report Spanish-language survey. Study participants consisted of 306 respondents between…

Higher order alchemical derivatives from coupled perturbed self-consistent field theory.

PubMed

Lesiuk, Michał; Balawender, Robert; Zachara, Janusz

2012-01-21

We present an analytical approach to treat higher order derivatives of Hartree-Fock (HF) and Kohn-Sham (KS) density functional theory energy in the Born-Oppenheimer approximation with respect to the nuclear charge distribution (so-called alchemical derivatives). Modified coupled perturbed self-consistent field theory is used to calculate molecular systems response to the applied perturbation. Working equations for the second and the third derivatives of HF/KS energy are derived. Similarly, analytical forms of the first and second derivatives of orbital energies are reported. The second derivative of Kohn-Sham energy and up to the third derivative of Hartree-Fock energy with respect to the nuclear charge distribution were calculated. Some issues of practical calculations, in particular the dependence of the basis set and Becke weighting functions on the perturbation, are considered. For selected series of isoelectronic molecules values of available alchemical derivatives were computed and Taylor series expansion was used to predict energies of the "surrounding" molecules. Predicted values of energies are in unexpectedly good agreement with the ones computed using HF/KS methods. Presented method allows one to predict orbital energies with the error less than 1% or even smaller for valence orbitals. © 2012 American Institute of Physics

Interplay between topology and disorder in a two-dimensional semi-Dirac material

NASA Astrophysics Data System (ADS)

Sriluckshmy, P. V.; Saha, Kush; Moessner, Roderich

2018-01-01

We investigate the role of disorder in a two-dimensional semi-Dirac material characterized by a linear dispersion in one direction and a parabolic dispersion in the orthogonal direction. Using the self-consistent Born approximation, we show that disorder can drive a topological Lifshitz transition from an insulator to a semimetal, as it generates a momentum-independent off-diagonal contribution to the self-energy. Breaking time-reversal symmetry enriches the topological phase diagram with three distinct regimes—single-node trivial, two-node trivial, and two-node Chern. We find that disorder can drive topological transitions from both the single- and two-node trivial to the two-node Chern regime. We further analyze these transitions in an appropriate tight-binding Hamiltonian of an anisotropic hexagonal lattice by calculating the real-space Chern number. Additionally, we compute the disorder-averaged entanglement entropy which signals both the topological Lifshitz and Chern transition as a function of the anisotropy of the hexagonal lattice. Finally, we discuss experimental aspects of our results.

Impurity doping effects on the orbital thermodynamic properties of hydrogenated graphene, graphane, in Harrison model

NASA Astrophysics Data System (ADS)

Yarmohammadi, Mohsen

2016-12-01

Using the Harrison model and Green's function technique, impurity doping effects on the orbital density of states (DOS), electronic heat capacity (EHC) and magnetic susceptibility (MS) of a monolayer hydrogenated graphene, chair-like graphane, are investigated. The effect of scattering between electrons and dilute charged impurities is discussed in terms of the self-consistent Born approximation. Our results show that the graphane is a semiconductor and its band gap decreases with impurity. As a remarkable point, comparatively EHC reaches almost linearly to Schottky anomaly and does not change at low temperatures in the presence of impurity. Generally, EHC and MS increases with impurity doping. Surprisingly, impurity doping only affects the salient behavior of py orbital contribution of carbon atoms due to the symmetry breaking.

Migration timing and parenting practices: Contributions to social development in preschoolers with foreign-born and native-born mothers

PubMed Central

Glick, Jennifer E.; Hanish, Laura D.; Yabiku, Scott T.; Bradley, Robert H.

2012-01-01

Little is known about how key aspects of parental migration or child-rearing history affect social development across children from immigrant families. Relying on data on approximately 6,400 children from the Early Childhood Longitudinal Study – Birth Cohort, analyses assessed the role of mothers’ age at migration on children’s social development in the United States (sociability and problem behaviors). Consistent with models of divergent adaptation and assimilation, the relationship between age at arrival and children’s social development is not linear. Parenting practices, observed when children were approximately 24 months of age, partially mediated the relation between mothers’ age at arrival and children’s social development reported at approximate age 48 months, particularly in the case of mothers who arrived as adults. PMID:22966921

Self-consistent approximation beyond the CPA: Part II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaplan, T.; Gray, L.J.

1981-08-01

In Part I, Professor Leath has described the substantial efforts to generalize the CPA. In this second part, a particular self-consistent approximation for random alloys developed by Kaplan, Leath, Gray, and Diehl is described. This approximation is applicable to diagonal, off-diagonal and environmental disorder, includes cluster scattering, and yields a translationally invariant and analytic (Herglotz) average Green's function. Furthermore Gray and Kaplan have shown that an approximation for alloys with short-range order can be constructed from this theory.

Optical-model potential for electron and positron elastic scattering by atoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salvat, Francesc

2003-07-01

An optical-model potential for systematic calculations of elastic scattering of electrons and positrons by atoms and positive ions is proposed. The electrostatic interaction is determined from the Dirac-Hartree-Fock self-consistent atomic electron density. In the case of electron projectiles, the exchange interaction is described by means of the local-approximation of Furness and McCarthy. The correlation-polarization potential is obtained by combining the correlation potential derived from the local density approximation with a long-range polarization interaction, which is represented by means of a Buckingham potential with an empirical energy-dependent cutoff parameter. The absorption potential is obtained from the local-density approximation, using the Born-Ochkurmore » approximation and the Lindhard dielectric function to describe the binary collisions with a free-electron gas. The strength of the absorption potential is adjusted by means of an empirical parameter, which has been determined by fitting available absolute elastic differential cross-section data for noble gases and mercury. The Dirac partial-wave analysis with this optical-model potential provides a realistic description of elastic scattering of electrons and positrons with energies in the range from {approx}100 eV up to {approx}5 keV. At higher energies, correlation-polarization and absorption corrections are small and the usual static-exchange approximation is sufficiently accurate for most practical purposes.« less

Non-linear 3-D Born shear waveform tomography in Southeast Asia

NASA Astrophysics Data System (ADS)

Panning, Mark P.; Cao, Aimin; Kim, Ahyi; Romanowicz, Barbara A.

2012-07-01

Southeast (SE) Asia is a tectonically complex region surrounded by many active source regions, thus an ideal test bed for developments in seismic tomography. Much recent development in tomography has been based on 3-D sensitivity kernels based on the first-order Born approximation, but there are potential problems with this approach when applied to waveform data. In this study, we develop a radially anisotropic model of SE Asia using long-period multimode waveforms. We use a theoretical 'cascade' approach, starting with a large-scale Eurasian model developed using 2-D Non-linear Asymptotic Coupling Theory (NACT) sensitivity kernels, and then using a modified Born approximation (nBorn), shown to be more accurate at modelling waveforms, to invert a subset of the data for structure in a subregion (longitude 75°-150° and latitude 0°-45°). In this subregion, the model is parametrized at a spherical spline level 6 (˜200 km). The data set is also inverted using NACT and purely linear 3-D Born kernels. All three final models fit the data well, with just under 80 per cent variance reduction as calculated using the corresponding theory, but the nBorn model shows more detailed structure than the NACT model throughout and has much better resolution at depths greater than 250 km. Based on variance analysis, the purely linear Born kernels do not provide as good a fit to the data due to deviations from linearity for the waveform data set used in this modelling. The nBorn isotropic model shows a stronger fast velocity anomaly beneath the Tibetan Plateau in the depth range of 150-250 km, which disappears at greater depth, consistent with other studies. It also indicates moderate thinning of the high-velocity plate in the middle of Tibet, consistent with a model where Tibet is underplated by Indian lithosphere from the south and Eurasian lithosphere from the north, in contrast to a model with continuous underplating by Indian lithosphere across the entire plateau. The nBorn anisotropic model detects negative ξ anomalies suggestive of vertical deformation associated with subducted slabs and convergent zones at the Himalayan front and Tien Shan at depths near 150 km.

Production of the Q2 doubly excited states of the hydrogen molecule by electron impact in a single step

NASA Astrophysics Data System (ADS)

Santos, Leonardo O.; Rocha, Alexandre B.; Faria, Nelson Velho de Castro; Jalbert, Ginette

2017-03-01

We calculate the single step cross sections for excitation of Q 2 states of H2 and its subsequent dissociation. The cross section calculations were performed within the first Born approximation and the electronic wave functions were obtained via State-Averaged Multiconfigurational Self-Consistent Field followed by Configuration Interaction. We have assumed autoionization is the only important process competing with dissociation into neutral atoms. We have estimated its probability through a semi classical approach and compared with results of literature. Special attention was given to the Q 2 1Σg +(1) state which, as has been shown in a previous work, may dissociate into H(2 sσ) + H(2 sσ) fragments (some figures in this article are in colour only in the electronic version).

A self-consistent treatment of a fluid in an external potential

NASA Astrophysics Data System (ADS)

Boudh-Hir, M.-E.

A simple fluid of particles near a repulsive structureless wall can be approximated by an identical fluid interacting with an ideal wall. The expansion in powers of the Andersen-Weeks-Chandler (AWC) blip function is used. Lado's criterion, which permits a self-consistent approximation, is extended to the surface case.

Health Disparities and Delayed Health care among Older Adults in California: A Perspective from Race, Ethnicity, and Immigration.

PubMed

Du, Yan; Xu, Qingwen

2016-09-01

To examine racial/ethnic/immigration disparities in health and to investigate the relationships among race/ethnic/immigration status, delayed health care, and health of the elderly. Responses from 13,508 people aged 65 and above were analyzed based on the California Health Interview Survey (CHIS) 2011-2012. Key variables include race/ethnicity/immigration status, health outcome, and delayed health care. Age, gender, education, work status, and annual family income are used as covariates. The findings indicate that Whites (regardless of country of birth) and U.S.-born Asians enjoy better health than Latinos, African-Americans, and Foreign-born Asians. Foreign-born Asians and foreign-born Latinos have the poorest self-reported health and mental health, respectively. Delayed use of health care is negatively associated with both self-reported health and mental health status. Health disparities exist among older adult populations; the combined effects of minority and immigrant status can be approximated from the results in this study. Health care accessibility and the quality of care should be promoted in minority/immigrant populations. Public health nurses have a strong potential to aide in reducing health disparities among an aging American population that continues to exhibit increasing racial/ethnic diversity. © 2016 Wiley Periodicals, Inc.

A Hydrodynamic Theory for Spatially Inhomogeneous Semiconductor Lasers: Microscopic Approach

NASA Technical Reports Server (NTRS)

Li, Jianzhong; Ning, C. Z.; Biegel, Bryan A. (Technical Monitor)

2001-01-01

Starting from the microscopic semiconductor Bloch equations (SBEs) including the Boltzmann transport terms in the distribution function equations for electrons and holes, we derived a closed set of diffusion equations for carrier densities and temperatures with self-consistent coupling to Maxwell's equation and to an effective optical polarization equation. The coherent many-body effects are included within the screened Hartree-Fock approximation, while scatterings are treated within the second Born approximation including both the in- and out-scatterings. Microscopic expressions for electron-hole (e-h) and carrier-LO (c-LO) phonon scatterings are directly used to derive the momentum and energy relaxation rates. These rates expressed as functions of temperatures and densities lead to microscopic expressions for self- and mutual-diffusion coefficients in the coupled density-temperature diffusion equations. Approximations for reducing the general two-component description of the electron-hole plasma (EHP) to a single-component one are discussed. In particular, we show that a special single-component reduction is possible when e-h scattering dominates over c-LO phonon scattering. The ambipolar diffusion approximation is also discussed and we show that the ambipolar diffusion coefficients are independent of e-h scattering, even though the diffusion coefficients of individual components depend sensitively on the e-h scattering rates. Our discussions lead to new perspectives into the roles played in the single-component reduction by the electron-hole correlation in momentum space induced by scatterings and the electron-hole correlation in real space via internal static electrical field. Finally, the theory is completed by coupling the diffusion equations to the lattice temperature equation and to the effective optical polarization which in turn couples to the laser field.

Quasiparticle self-consistent GW method for the spectral properties of complex materials.

PubMed

Bruneval, Fabien; Gatti, Matteo

2014-01-01

The GW approximation to the formally exact many-body perturbation theory has been applied successfully to materials for several decades. Since the practical calculations are extremely cumbersome, the GW self-energy is most commonly evaluated using a first-order perturbative approach: This is the so-called G 0 W 0 scheme. However, the G 0 W 0 approximation depends heavily on the mean-field theory that is employed as a basis for the perturbation theory. Recently, a procedure to reach a kind of self-consistency within the GW framework has been proposed. The quasiparticle self-consistent GW (QSGW) approximation retains some positive aspects of a self-consistent approach, but circumvents the intricacies of the complete GW theory, which is inconveniently based on a non-Hermitian and dynamical self-energy. This new scheme allows one to surmount most of the flaws of the usual G 0 W 0 at a moderate calculation cost and at a reasonable implementation burden. In particular, the issues of small band gap semiconductors, of large band gap insulators, and of some transition metal oxides are then cured. The QSGW method broadens the range of materials for which the spectral properties can be predicted with confidence.

Born approximation in linear-time invariant system

NASA Astrophysics Data System (ADS)

Gumjudpai, Burin

2017-09-01

An alternative way of finding the LTI’s solution with the Born approximation, is investigated. We use Born approximation in the LTI and in the transformed LTI in form of Helmholtz equation. General solution are considered as infinite series or Feynman graph. Slow-roll approximation are explored. Transforming the LTI system into Helmholtz equation, approximated general solution can be found for any given forms of force with its initial value.

Differences in the self-reported racism experiences of US-born and foreign-born Black pregnant women

PubMed Central

Dominguez, Tyan Parker; Strong, Emily Ficklin; Krieger, Nancy; Gillman, Matthew W.; Rich-Edwards, Janet W.

2013-01-01

Differential exposure to minority status stressors may help explain differences in United States (US)-born and foreign-born Black women’s birth outcomes. We explored self-reports of racism recorded in a survey of 185 US-born and 114 foreign-born Black pregnant women enrolled in Project Viva, a prospective cohort study of pregnant women in Boston, Massachusetts, USA. Self-reported prevalence of personal racism and group racism was significantly higher among US-born than foreign-born Black pregnant women, with US-born women having 4.1 and 7.8 times the odds, respectively, of childhood exposure. In multivariate analyses, US-born women’s personal and group racism exposure also was more pervasive across the eight life domains we queried. Examined by immigrant subgroups, US-born women were more similar in their self-reports of racism to foreign-born women who moved to the US before age 18 than to women who immigrated after age 18. Moreover, US-born women more closely resembled foreign-born women from the Caribbean than those from Africa. Differential exposure to self-reported racism over the life course may be a critically important factor that distinguishes US-born Black women from their foreign-born counterparts. PMID:19386406

Non-Born-Oppenheimer self-consistent field calculations with cubic scaling

NASA Astrophysics Data System (ADS)

Moncada, Félix; Posada, Edwin; Flores-Moreno, Roberto; Reyes, Andrés

2012-05-01

An efficient nuclear molecular orbital methodology is presented. This approach combines an auxiliary density functional theory for electrons (ADFT) and a localized Hartree product (LHP) representation for the nuclear wave function. A series of test calculations conducted on small molecules exposed that energy and geometry errors introduced by the use of ADFT and LHP approximations are small and comparable to those obtained by the use of electronic ADFT. In addition, sample calculations performed on (HF)n chains disclosed that the combined ADFT/LHP approach scales cubically with system size (n) as opposed to the quartic scaling of Hartree-Fock/LHP or DFT/LHP methods. Even for medium size molecules the improved scaling of the ADFT/LHP approach resulted in speedups of at least 5x with respect to Hartree-Fock/LHP calculations. The ADFT/LHP method opens up the possibility of studying nuclear quantum effects on large size systems that otherwise would be impractical.

Generalized One-Band Model Based on Zhang-Rice Singlets for Tetragonal CuO.

PubMed

Hamad, I J; Manuel, L O; Aligia, A A

2018-04-27

Tetragonal CuO (T-CuO) has attracted attention because of its structure similar to that of the cuprates. It has been recently proposed as a compound whose study can give an end to the long debate about the proper microscopic modeling for cuprates. In this work, we rigorously derive an effective one-band generalized t-J model for T-CuO, based on orthogonalized Zhang-Rice singlets, and make an estimative calculation of its parameters, based on previous ab initio calculations. By means of the self-consistent Born approximation, we then evaluate the spectral function and the quasiparticle dispersion for a single hole doped in antiferromagnetically ordered half filled T-CuO. Our predictions show very good agreement with angle-resolved photoemission spectra and with theoretical multiband results. We conclude that a generalized t-J model remains the minimal Hamiltonian for a correct description of single-hole dynamics in cuprates.

Quantum transport in antidot arrays in magnetic fields

NASA Astrophysics Data System (ADS)

Ishizaka, Satoshi; Nihey, Fumiyuki; Nakamura, Kazuo; Sone, Jun' Ichi; Ando, Tsuneya

1995-04-01

Transport in antidot arrays in magnetic fields is studied numerically. We calculate the density of states and conductivity tensor by the self-consistent Born approximation. Although peak positions of the density of states agree well with the quantization condition for several short periodic orbits, the behavior of the conductivity tensor is very complicated. Coupling among the periodic orbits causes an oscillation in the Hall conductivity in magnetic fields around the localized peak. In low magnetic fields, the skipping orbit, which runs from an antidot to its neighboring antidot, plays a crucial role for diagonal conductivity, and its coupling with the periodic orbits causes an oscillation in the diagonal conductivity. The resulting magnetoresistance oscillates with a period near one magnetic flux quantum as observed in recent experiments. Furthermore, the oscillation due to the manifestation of Hofstadter's butterfly is present in both the diagonal conductivity and the Hall conductivity.

Generalized One-Band Model Based on Zhang-Rice Singlets for Tetragonal CuO

NASA Astrophysics Data System (ADS)

Hamad, I. J.; Manuel, L. O.; Aligia, A. A.

2018-04-01

Tetragonal CuO (T-CuO) has attracted attention because of its structure similar to that of the cuprates. It has been recently proposed as a compound whose study can give an end to the long debate about the proper microscopic modeling for cuprates. In this work, we rigorously derive an effective one-band generalized t -J model for T-CuO, based on orthogonalized Zhang-Rice singlets, and make an estimative calculation of its parameters, based on previous ab initio calculations. By means of the self-consistent Born approximation, we then evaluate the spectral function and the quasiparticle dispersion for a single hole doped in antiferromagnetically ordered half filled T-CuO. Our predictions show very good agreement with angle-resolved photoemission spectra and with theoretical multiband results. We conclude that a generalized t -J model remains the minimal Hamiltonian for a correct description of single-hole dynamics in cuprates.

Controlling Thermodynamic Properties of Ferromagnetic Group-IV Graphene-Like Nanosheets by Dilute Charged Impurity

NASA Astrophysics Data System (ADS)

Yarmohammadi, Mohsen; Mirabbaszadeh, Kavoos

2017-05-01

Using the Kane-Mele Hamiltonian, Dirac theory and self-consistent Born approximation, we investigate the effect of dilute charged impurity on the electronic heat capacity and magnetic susceptibility of two-dimensional ferromagnetic honeycomb structure of group-IV elements including silicene, germanene and stanene within the Green’s function approach. We also find these quantities in the presence of applied external electric field. Our results show that the silicene (stanene) has the maximum (minimum) heat capacity and magnetic susceptibility at uniform electric fields. From the behavior of theses quantities, the band gap has been changed with impurity concentration, impurity scattering strength and electric field. The analysis on the impurity-dependent magnetic susceptibility curves shows a phase transition from ferromagnetic to paramagnetic and antiferromagnetic phases. Interestingly, electronic heat capacity increases (decreases) with impurity concentration in silicene (germanene and stanene) structure.

Vibrationally averaged post Born-Oppenheimer isotopic dipole moment calculations approaching spectroscopic accuracy.

PubMed

Arapiraca, A F C; Jonsson, Dan; Mohallem, J R

2011-12-28

We report an upgrade of the Dalton code to include post Born-Oppenheimer nuclear mass corrections in the calculations of (ro-)vibrational averages of molecular properties. These corrections are necessary to achieve an accuracy of 10(-4) debye in the calculations of isotopic dipole moments. Calculations on the self-consistent field level present this accuracy, while numerical instabilities compromise correlated calculations. Applications to HD, ethane, and ethylene isotopologues are implemented, all of them approaching the experimental values.

Charge dynamics of the antiferromagnetically ordered Mott insulator

NASA Astrophysics Data System (ADS)

Han, Xing-Jie; Liu, Yu; Liu, Zhi-Yuan; Li, Xin; Chen, Jing; Liao, Hai-Jun; Xie, Zhi-Yuan; Normand, B.; Xiang, Tao

2016-10-01

We introduce a slave-fermion formulation in which to study the charge dynamics of the half-filled Hubbard model on the square lattice. In this description, the charge degrees of freedom are represented by fermionic holons and doublons and the Mott-insulating characteristics of the ground state are the consequence of holon-doublon bound-state formation. The bosonic spin degrees of freedom are described by the antiferromagnetic Heisenberg model, yielding long-ranged (Néel) magnetic order at zero temperature. Within this framework and in the self-consistent Born approximation, we perform systematic calculations of the average double occupancy, the electronic density of states, the spectral function and the optical conductivity. Qualitatively, our method reproduces the lower and upper Hubbard bands, the spectral-weight transfer into a coherent quasiparticle band at their lower edges and the renormalisation of the Mott gap, which is associated with holon-doublon binding, due to the interactions of both quasiparticle species with the magnons. The zeros of the Green function at the chemical potential give the Luttinger volume, the poles of the self-energy reflect the underlying quasiparticle dispersion with a spin-renormalised hopping parameter and the optical gap is directly related to the Mott gap. Quantitatively, the square-lattice Hubbard model is one of the best-characterised problems in correlated condensed matter and many numerical calculations, all with different strengths and weaknesses, exist with which to benchmark our approach. From the semi-quantitative accuracy of our results for all but the weakest interaction strengths, we conclude that a self-consistent treatment of the spin-fluctuation effects on the charge degrees of freedom captures all the essential physics of the antiferromagnetic Mott-Hubbard insulator. We remark in addition that an analytical approximation with these properties serves a vital function in developing a full understanding of the fundamental physics of the Mott state, both in the antiferromagnetic insulator and at finite temperatures and dopings.

Correction of the near threshold behavior of electron collisional excitation cross-sections in the plane-wave Born approximation

NASA Astrophysics Data System (ADS)

Kilcrease, D. P.; Brookes, S.

2013-12-01

The modeling of NLTE plasmas requires the solution of population rate equations to determine the populations of the various atomic levels relevant to a particular problem. The equations require many cross sections for excitation, de-excitation, ionization and recombination. A simple and computational fast way to calculate electron collisional excitation cross-sections for ions is by using the plane-wave Born approximation. This is essentially a high-energy approximation and the cross section suffers from the unphysical problem of going to zero near threshold. Various remedies for this problem have been employed with varying degrees of success. We present a correction procedure for the Born cross-sections that employs the Elwert-Sommerfeld factor to correct for the use of plane waves instead of Coulomb waves in an attempt to produce a cross-section similar to that from using the more time consuming Coulomb Born approximation. We compare this new approximation with other, often employed correction procedures. We also look at some further modifications to our Born Elwert procedure and its combination with Y.K. Kim's correction of the Coulomb Born approximation for singly charged ions that more accurately approximate convergent close coupling calculations.

Correction of the near threshold behavior of electron collisional excitation cross-sections in the plane-wave Born approximation

DOE PAGES

Kilcrease, D. P.; Brookes, S.

2013-08-19

The modeling of NLTE plasmas requires the solution of population rate equations to determine the populations of the various atomic levels relevant to a particular problem. The equations require many cross sections for excitation, de-excitation, ionization and recombination. Additionally, a simple and computational fast way to calculate electron collisional excitation cross-sections for ions is by using the plane-wave Born approximation. This is essentially a high-energy approximation and the cross section suffers from the unphysical problem of going to zero near threshold. Various remedies for this problem have been employed with varying degrees of success. We present a correction procedure formore » the Born cross-sections that employs the Elwert–Sommerfeld factor to correct for the use of plane waves instead of Coulomb waves in an attempt to produce a cross-section similar to that from using the more time consuming Coulomb Born approximation. We compare this new approximation with other, often employed correction procedures. Furthermore, we also look at some further modifications to our Born Elwert procedure and its combination with Y.K. Kim's correction of the Coulomb Born approximation for singly charged ions that more accurately approximate convergent close coupling calculations.« less

Inelastic transport theory from first principles: Methodology and application to nanoscale devices

NASA Astrophysics Data System (ADS)

Frederiksen, Thomas; Paulsson, Magnus; Brandbyge, Mads; Jauho, Antti-Pekka

2007-05-01

We describe a first-principles method for calculating electronic structure, vibrational modes and frequencies, electron-phonon couplings, and inelastic electron transport properties of an atomic-scale device bridging two metallic contacts under nonequilibrium conditions. The method extends the density-functional codes SIESTA and TRANSIESTA that use atomic basis sets. The inelastic conductance characteristics are calculated using the nonequilibrium Green’s function formalism, and the electron-phonon interaction is addressed with perturbation theory up to the level of the self-consistent Born approximation. While these calculations often are computationally demanding, we show how they can be approximated by a simple and efficient lowest order expansion. Our method also addresses effects of energy dissipation and local heating of the junction via detailed calculations of the power flow. We demonstrate the developed procedures by considering inelastic transport through atomic gold wires of various lengths, thereby extending the results presented in Frederiksen [Phys. Rev. Lett. 93, 256601 (2004)]. To illustrate that the method applies more generally to molecular devices, we also calculate the inelastic current through different hydrocarbon molecules between gold electrodes. Both for the wires and the molecules our theory is in quantitative agreement with experiments, and characterizes the system-specific mode selectivity and local heating.

Quantitative verification of ab initio self-consistent laser theory.

PubMed

Ge, Li; Tandy, Robert J; Stone, A D; Türeci, Hakan E

2008-10-13

We generalize and test the recent "ab initio" self-consistent (AISC) time-independent semiclassical laser theory. This self-consistent formalism generates all the stationary lasing properties in the multimode regime (frequencies, thresholds, internal and external fields, output power and emission pattern) from simple inputs: the dielectric function of the passive cavity, the atomic transition frequency, and the transverse relaxation time of the lasing transition.We find that the theory gives excellent quantitative agreement with full time-dependent simulations of the Maxwell-Bloch equations after it has been generalized to drop the slowly-varying envelope approximation. The theory is infinite order in the non-linear hole-burning interaction; the widely used third order approximation is shown to fail badly.

Birth order and its relationship to depression, anxiety, and self-concept test scores in children.

PubMed

Gates, L; Lineberger, M R; Crockett, J; Hubbard, J

1988-03-01

Children (N = 404), 7 to 12 years old, were given the Children's Depression Inventory, the State-Trait Anxiety Inventory for Children, and the Piers-Harris Self-Concept Scale. First-born children scored significantly lower on depression than second-, third-, fourth-born, and youngest children. First borns showed significantly less trait anxiety than third-born children. First-born children also showed significantly higher levels of self-esteem than second-born and youngest children. Girls in this study showed significantly more trait anxiety than boys.

Self-consistent-field KKR-CPA calculations in the atomic-sphere approximations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, P.P. Gonis, A.; de Fontaine, D.

1991-12-03

We present a formulation of the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) for the treatment of substitutionally disordered alloys within the KKR atomic-sphere approximations (ASA). This KKR-ASA-CPA represents the first step toward the implementation of a full cell potential CPA, and combines the accuracy of the KKR-CPA method with the flexibility of treating complex crystal structures. The accuracy of this approach has been tested by comparing the self-consistent-field (SCF) KKR-ASA-CPA calculations of Cu-Pd alloys with experimental results and previous SCF-KKR-CPA calculations.

Heisenberg-Langevin versus quantum master equation

NASA Astrophysics Data System (ADS)

Boyanovsky, Daniel; Jasnow, David

2017-12-01

The quantum master equation is an important tool in the study of quantum open systems. It is often derived under a set of approximations, chief among them the Born (factorization) and Markov (neglect of memory effects) approximations. In this article we study the paradigmatic model of quantum Brownian motion of a harmonic oscillator coupled to a bath of oscillators with a Drude-Ohmic spectral density. We obtain analytically the exact solution of the Heisenberg-Langevin equations, with which we study correlation functions in the asymptotic stationary state. We compare the exact correlation functions to those obtained in the asymptotic long time limit with the quantum master equation in the Born approximation with and without the Markov approximation. In the latter case we implement a systematic derivative expansion that yields the exact asymptotic limit under the factorization approximation only. We find discrepancies that could be significant when the bandwidth of the bath Λ is much larger than the typical scales of the system. We study the exact interaction energy as a proxy for the correlations missed by the Born approximation and find that its dependence on Λ is similar to the discrepancy between the exact solution and that of the quantum master equation in the Born approximation. We quantify the regime of validity of the quantum master equation in the Born approximation with or without the Markov approximation in terms of the system's relaxation rate γ , its unrenormalized natural frequency Ω and Λ : γ /Ω ≪1 and also γ Λ /Ω2≪1 . The reliability of the Born approximation is discussed within the context of recent experimental settings and more general environments.

On Born approximation in black hole scattering

NASA Astrophysics Data System (ADS)

Batic, D.; Kelkar, N. G.; Nowakowski, M.

2011-12-01

A massless field propagating on spherically symmetric black hole metrics such as the Schwarzschild, Reissner-Nordström and Reissner-Nordström-de Sitter backgrounds is considered. In particular, explicit formulae in terms of transcendental functions for the scattering of massless scalar particles off black holes are derived within a Born approximation. It is shown that the conditions on the existence of the Born integral forbid a straightforward extraction of the quasi normal modes using the Born approximation for the scattering amplitude. Such a method has been used in literature. We suggest a novel, well defined method, to extract the large imaginary part of quasinormal modes via the Coulomb-like phase shift. Furthermore, we compare the numerically evaluated exact scattering amplitude with the Born one to find that the approximation is not very useful for the scattering of massless scalar, electromagnetic as well as gravitational waves from black holes.

Creating a Business Plan and Projecting Revenue for a Cosmetic Laser Center in a Community Hospital

DTIC Science & Technology

2000-05-01

at $300.00. Expenses for physician faculty were borne by ESC Sharplan. Overhead. Overhead was based upon $2.75 per square foot per month, or...33.00 per square foot per year. Total square footage of the laser center is approximately 300 square foot ($9,900 per year) (Sound Shore Finance...of holistic nursing therapies, including self- hypnosis, guided imagery, reflexology and therapeutic touch, into patient care. Establishing a Laser

Generalized extended Lagrangian Born-Oppenheimer molecular dynamics

DOE PAGES

Niklasson, Anders M. N.; Cawkwell, Marc J.

2014-10-29

Extended Lagrangian Born-Oppenheimer molecular dynamics based on Kohn-Sham density functional theory is generalized in the limit of vanishing self-consistent field optimization prior to the force evaluations. The equations of motion are derived directly from the extended Lagrangian under the condition of an adiabatic separation between the nuclear and the electronic degrees of freedom. We show how this separation is automatically fulfilled and system independent. The generalized equations of motion require only one diagonalization per time step and are applicable to a broader range of materials with improved accuracy and stability compared to previous formulations.

Optically adjustable valley Hall current in single-layer transition metal dichalcogenides

NASA Astrophysics Data System (ADS)

Sengupta, Parijat; Pavlidis, Dimitris; Shi, Junxia

2018-02-01

The illumination of a single-layer transition metal dichalcogenide with an elliptically polarized light beam is shown to give rise to a differential rate of inter-band carrier excitation between the valence and conduction states around the valley edges, K and K' . This rate with a linear dependence on the beam ellipticity and inverse of the optical gap manifests as an asymmetric Fermi distribution between the valleys or a non-equilibrium population which under an external field and a Berry curvature induced anomalous velocity, results in an externally tunable finite valley Hall current. Surface imperfections that influence the excitation rates are included through the self-consistent Born approximation. Further, we describe applications centered around circular dichroism, quantum computing, and spin torque via optically excited spin currents within the framework of the suggested formalism. A closing summary points to the possibility of extending the calculations to composite charged particles like trions. The role of the substrate in renormalizing the fundamental band gap and moderating the valley Hall current is also discussed.

Transient carrier dynamics in a Mott insulator with antiferromagnetic order

NASA Astrophysics Data System (ADS)

Iyoda, Eiki; Ishihara, Sumio

2014-03-01

We study transient dynamics of hole carriers injected into a Mott insulator with antiferromagnetic long-range order. This "dynamical hole doping" contrasts with chemical hole doping. The theoretical framework for the transient carrier dynamics is presented based on the two-dimensional t-J model. The time dependencies of the optical conductivity spectra, as well as the one-particle excitation spectra, are calculated based on the Keldysh Green's function formalism at zero temperature combined with the self-consistent Born approximation. In the early stage after dynamical hole doping, the Drude component appears, and then incoherent components originating from hole-magnon scattering start to grow. Fast oscillatory behavior owing to coherent magnon and slow relaxation dynamics are confirmed in the spectra. The time profiles are interpreted as doped bare holes being dressed by magnon clouds and relaxed into spin polaron quasiparticle states. The characteristic relaxation times for Drude and incoherent peaks strongly depend on the momentum of the dynamically doped hole and the exchange constant. Implications for recent pump-probe experiments are discussed.

Self-consistency tests of large-scale dynamics parameterizations for single-column modeling

DOE PAGES

Edman, Jacob P.; Romps, David M.

2015-03-18

Large-scale dynamics parameterizations are tested numerically in cloud-resolving simulations, including a new version of the weak-pressure-gradient approximation (WPG) introduced by Edman and Romps (2014), the weak-temperature-gradient approximation (WTG), and a prior implementation of WPG. We perform a series of self-consistency tests with each large-scale dynamics parameterization, in which we compare the result of a cloud-resolving simulation coupled to WTG or WPG with an otherwise identical simulation with prescribed large-scale convergence. In self-consistency tests based on radiative-convective equilibrium (RCE; i.e., no large-scale convergence), we find that simulations either weakly coupled or strongly coupled to either WPG or WTG are self-consistent, butmore » WPG-coupled simulations exhibit a nonmonotonic behavior as the strength of the coupling to WPG is varied. We also perform self-consistency tests based on observed forcings from two observational campaigns: the Tropical Warm Pool International Cloud Experiment (TWP-ICE) and the ARM Southern Great Plains (SGP) Summer 1995 IOP. In these tests, we show that the new version of WPG improves upon prior versions of WPG by eliminating a potentially troublesome gravity-wave resonance.« less

The association of self-rated health and lifestyle behaviors among foreign-born Chinese, Korean, and Vietnamese Americans.

PubMed

Tran, Thanh V; Nguyen, Duy; Chan, Keith; Nguyen, Thuc-Nhi

2013-03-01

This study employed the 2009 California Health Interview Survey to examine the association of self-rated heath status and lifestyle behavior variables such as smoking at least 100 cigarettes or more in an entire lifetime, alcohol consumption, and physical activity level among foreign-born Chinese, Korean, and Vietnamese Americans aged 18 and older. The total study sample consisted of 3,023 foreign-born adult Chinese (n = 812), Korean (n = 857), and Vietnamese (n = 1,354) Americans. Logistic regression via Stata 12 was employed. Odds ratios (OR) along with confidence intervals (CI) were reported in the results. Results revealed that smoking at least 100 cigarettes or more in an entire lifetime had a negative association with good health status (OR = 0.74, 95 % CI = 0.59, 0.94), while alcohol consumption had a positive association with good health status (OR = 1.20, 95 % CI = 1.00, 1.44). Moderate physical activity (OR = 1.26, 95 % CI = 1.05, 1.50) and vigorous physical activity (OR = 1.68, 95 % CI = 1.31, 2.15) had a similar positive association with good self-rated health status. The results also revealed that the predicted probability of self-rated health status based on ethnicity and lifestyle variables was more favorable for foreign-born Chinese Americans than their Korean and Vietnamese American counterparts. This study's results corroborated the findings reported in previous research on the association of lifestyle behaviors and health status. Regardless of racial or ethnic backgrounds, good lifestyles have an important role in the prevention of poor health status. However, health education and lifestyle intervention programs should take cultural differences among racial and ethnic populations into consideration.

Nonequilibrium Green's functions and atom-surface dynamics: Simple views from a simple model system

NASA Astrophysics Data System (ADS)

Boström, E.; Hopjan, M.; Kartsev, A.; Verdozzi, C.; Almbladh, C.-O.

2016-03-01

We employ Non-equilibrium Green's functions (NEGF) to describe the real-time dynamics of an adsorbate-surface model system exposed to ultrafast laser pulses. For a finite number of electronic orbitals, the system is solved exactly and within different levels of approximation. Specifically i) the full exact quantum mechanical solution for electron and nuclear degrees of freedom is used to benchmark ii) the Ehrenfest approximation (EA) for the nuclei, with the electron dynamics still treated exactly. Then, using the EA, electronic correlations are treated with NEGF within iii) 2nd Born and with iv) a recently introduced hybrid scheme, which mixes 2nd Born self-energies with non-perturbative, local exchange- correlation potentials of Density Functional Theory (DFT). Finally, the effect of a semi-infinite substrate is considered: we observe that a macroscopic number of de-excitation channels can hinder desorption. While very preliminary in character and based on a simple and rather specific model system, our results clearly illustrate the large potential of NEGF to investigate atomic desorption, and more generally, the non equilibrium dynamics of material surfaces subject to ultrafast laser fields.

Self-consistency in the phonon space of the particle-phonon coupling model

NASA Astrophysics Data System (ADS)

Tselyaev, V.; Lyutorovich, N.; Speth, J.; Reinhard, P.-G.

2018-04-01

In the paper the nonlinear generalization of the time blocking approximation (TBA) is presented. The TBA is one of the versions of the extended random-phase approximation (RPA) developed within the Green-function method and the particle-phonon coupling model. In the generalized version of the TBA the self-consistency principle is extended onto the phonon space of the model. The numerical examples show that this nonlinear version of the TBA leads to the convergence of results with respect to enlarging the phonon space of the model.

Accuracy of the Generalized Self-Consistent Method in Modelling the Elastic Behaviour of Periodic Composites

NASA Technical Reports Server (NTRS)

Walker, Kevin P.; Freed, Alan D.; Jordan, Eric H.

1993-01-01

Local stress and strain fields in the unit cell of an infinite, two-dimensional, periodic fibrous lattice have been determined by an integral equation approach. The effect of the fibres is assimilated to an infinite two-dimensional array of fictitious body forces in the matrix constituent phase of the unit cell. By subtracting a volume averaged strain polarization term from the integral equation we effectively embed a finite number of unit cells in a homogenized medium in which the overall stress and strain correspond to the volume averaged stress and strain of the constrained unit cell. This paper demonstrates that the zeroth term in the governing integral equation expansion, which embeds one unit cell in the homogenized medium, corresponds to the generalized self-consistent approximation. By comparing the zeroth term approximation with higher order approximations to the integral equation summation, both the accuracy of the generalized self-consistent composite model and the rate of convergence of the integral summation can be assessed. Two example composites are studied. For a tungsten/copper elastic fibrous composite the generalized self-consistent model is shown to provide accurate, effective, elastic moduli and local field representations. The local elastic transverse stress field within the representative volume element of the generalized self-consistent method is shown to be in error by much larger amounts for a composite with periodically distributed voids, but homogenization leads to a cancelling of errors, and the effective transverse Young's modulus of the voided composite is shown to be in error by only 23% at a void volume fraction of 75%.

Born approximation for scattering by evanescent waves: Comparison with exact scattering by an infinite fluid cylinder

NASA Astrophysics Data System (ADS)

Marston, Philip L.

2004-05-01

In some situations, evanescent waves can be an important component of the acoustic field within the sea bottom. For this reason (as well as to advance the understanding of scattering processes) it can be helpful to examine the modifications to scattering theory resulting from evanescence. Modifications to ray theory were examined in a prior approximation [P. L. Marston, J. Acoust. Soc. Am. 113, 2320 (2003)]. The new research concerns the modifications to the low-frequency Born approximation and confirmation by comparison with the exact two-dimensional scattering by a fluid cylinder. In the case of a circular cylinder having the same density as the surroundings but having a compressibility contrast with the surroundings, the Born approximation with a nonevanescent incident wave gives only monopole scattering. When the cylinder has a density contrast and the same compressibility as the surroundings the regular Born approximation gives only dipole scattering (with the dipole oriented along to the incident wavevector). In both cases when the Born approximation is modified to include the evanescence of the incident wave, an additional dipole scattering term is evident. In each case the new dipole is oriented along to the decay axis of the evanescent wave. [Research supported by ONR.

Extended Lagrangian Density Functional Tight-Binding Molecular Dynamics for Molecules and Solids.

PubMed

Aradi, Bálint; Niklasson, Anders M N; Frauenheim, Thomas

2015-07-14

A computationally fast quantum mechanical molecular dynamics scheme using an extended Lagrangian density functional tight-binding formulation has been developed and implemented in the DFTB+ electronic structure program package for simulations of solids and molecular systems. The scheme combines the computational speed of self-consistent density functional tight-binding theory with the efficiency and long-term accuracy of extended Lagrangian Born-Oppenheimer molecular dynamics. For systems without self-consistent charge instabilities, only a single diagonalization or construction of the single-particle density matrix is required in each time step. The molecular dynamics simulation scheme can be applied to a broad range of problems in materials science, chemistry, and biology.

An Examination of Cultural Values and Pain Management in Foreign-Born Spanish-Speaking Hispanics Seeking Care at a Federally Qualified Health Center.

PubMed

Torres, Calia A; Thorn, Beverly E; Kapoor, Shweta; DeMonte, Colette

2017-11-01

Most studies done with Hispanics illustrate their preference for self-management practices; therefore, examining the factors driving patients to seek medical care for pain management will help elucidate what patients want and need from their doctors for pain management. The aim of the present study was to obtain patients' perspectives and enhance our understanding of the cultural beliefs influencing pain management decisions of foreign-born Spanish-speaking Hispanics with low acculturation. Twenty-four individuals (17 females and 7 males) with self-reported chronic pain completed the study. Participants attended a focus group and shared about pain management practices and their experiences with medical care for pain management. Descriptive data on pain and mood variables were collected to examine how this population compares with the norms reported in the pain literature for Hispanics. Participants reported a preference for pain self-management and noninvasive medical treatments and expressed negative attitudes toward pain medications, although wanting the option of pain medications as a "last resort." Satisfaction with medical care for pain was highly influenced by the participants' expectations and preference for personal, warm, and friendly interactions. Our findings are consistent with previous reports on Hispanics' preference for self-care practices. Perhaps foreign-born Hispanics may rely on self-care practices and delay medical attention for pain management because of their unfamiliarity with the US health care system. Other potential explanations for a reliance on self-care for pain management involve patients having a limited understanding of or access to effective treatment options for chronic pain and negative experiences with US medical providers. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Supersymmetric Dirac Born Infeld action with self-dual mass term

NASA Astrophysics Data System (ADS)

Nishino, Hitoshi; Rajpoot, Subhash; Reed, Kevin

2005-05-01

We introduce a Dirac Born Infeld action to a self-dual N = 1 supersymmetric vector multiplet in three dimensions. This action is based on the supersymmetric generalized self-duality in odd dimensions developed originally by Townsend, Pilch and van Nieuwenhuizen. Even though such a self-duality had been supposed to be very difficult to generalize to a supersymmetrically interacting system, we show that the Dirac Born Infeld action is actually compatible with supersymmetry and self-duality in three dimensions, even though the original self-duality receives corrections by the Dirac Born Infeld action. The interactions can be further generalized to arbitrary (non)polynomial interactions. As a by-product, we also show that a third-rank field strength leads to a more natural formulation of self-duality in 3D. We also show an interesting role played by the third-rank field strength leading to supersymmetry breaking, in addition to accommodating a Chern Simons form.

Molecular Detection of Tick-Borne Pathogens in Humans with Tick Bites and Erythema Migrans, in the Netherlands

PubMed Central

Jahfari, Setareh; Hofhuis, Agnetha; Fonville, Manoj; van der Giessen, Joke; van Pelt, Wilfrid; Sprong, Hein

2016-01-01

Background Tick-borne diseases are the most prevalent vector-borne diseases in Europe. Knowledge on the incidence and clinical presentation of other tick-borne diseases than Lyme borreliosis and tick-borne encephalitis is minimal, despite the high human exposure to these pathogens through tick bites. Using molecular detection techniques, the frequency of tick-borne infections after exposure through tick bites was estimated. Methods Ticks, blood samples and questionnaires on health status were collected from patients that visited their general practitioner with a tick bite or erythema migrans in 2007 and 2008. The presence of several tick-borne pathogens in 314 ticks and 626 blood samples of this cohort were analyzed using PCR-based methods. Using multivariate logistic regression, associations were explored between pathogens detected in blood and self-reported symptoms at enrolment and during a three-month follow-up period. Results Half of the ticks removed from humans tested positive for Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Candidatus Neoehrlichia mikurensis, Rickettsia helvetica, Rickettsia monacensis, Borrelia miyamotoi and several Babesia species. Among 92 Borrelia burgdorferi s. l. positive ticks, 33% carried another pathogen from a different genus. In blood of sixteen out of 626 persons with tick bites or erythema migrans, DNA was detected from Candidatus Neoehrlichia mikurensis (n = 7), Anaplasma phagocytophilum (n = 5), Babesia divergens (n = 3), Borrelia miyamotoi (n = 1) and Borrelia burgdorferi s. l. (n = 1). None of these sixteen individuals reported any overt symptoms that would indicate a corresponding illness during the three-month follow-up period. No associations were found between the presence of pathogen DNA in blood and; self-reported symptoms, with pathogen DNA in the corresponding ticks (n = 8), reported tick attachment duration, tick engorgement, or antibiotic treatment at enrolment. Conclusions Based on molecular detection techniques, the probability of infection with a tick-borne pathogen other than Lyme spirochetes after a tick bite is roughly 2.4%, in the Netherlands. Similarly, among patients with erythema migrans, the probability of a co-infection with another tick-borne pathogen is approximately 2.7%. How often these infections cause disease symptoms or to what extend co-infections affect the course of Lyme borreliosis needs further investigations. PMID:27706159

Relativistic equation of state at subnuclear densities in the Thomas-Fermi approximation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Z. W.; Shen, H., E-mail: shennankai@gmail.com

We study the non-uniform nuclear matter using the self-consistent Thomas-Fermi approximation with a relativistic mean-field model. The non-uniform matter is assumed to be composed of a lattice of heavy nuclei surrounded by dripped nucleons. At each temperature T, proton fraction Y{sub p} , and baryon mass density ρ {sub B}, we determine the thermodynamically favored state by minimizing the free energy with respect to the radius of the Wigner-Seitz cell, while the nucleon distribution in the cell can be determined self-consistently in the Thomas-Fermi approximation. A detailed comparison is made between the present results and previous calculations in the Thomas-Fermimore » approximation with a parameterized nucleon distribution that has been adopted in the widely used Shen equation of state.« less

Collisional excitation of the highly excited hydrogen atoms in the dipole form of the semiclassical impact parameter and Born approximations

NASA Technical Reports Server (NTRS)

Omidvar, K.

1971-01-01

Expressions for the excitation cross section of the highly excited states of the hydrogenlike atoms by fast charged particles have been derived in the dipole approximation of the semiclassical impact parameter and the Born approximations, making use of a formula for the asymptotic expansion of the oscillator strength of the hydrogenlike atoms given by Menzel. When only the leading term in the asymptotic expansion is retained, the expression for the cross section becomes identical to the expression obtained by the method of the classical collision and correspondence principle given by Percival and Richards. Comparisons are made between the Bethe coefficients obtained here and the Bethe coefficients of the Born approximation for transitions where the Born calculation is available. Satisfactory agreement is obtained only for n yields n + 1 transitions, with n the principal quantum number of the excited state.

A molecular Debye-Huckel theory of solvation in polar fluids: An extension of the Born model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Tiejun; Song, Xueyu

A dielectric response theory of solvation beyond the conventional Born model for polar fluids is presented. The dielectric response of a polar fluid is described by a Born response mode and a linear combination of Debye-Hückel-like response modes that capture the nonlocal response of polar fluids. The Born mode is characterized by a bulk dielectric constant, while a Debye-Hückel mode is characterized by its corresponding Debye screening length. Both the bulk dielectric constant and the Debye screening lengths are determined from the bulk dielectric function of the polar fluid. The linear combination coefficients of the response modes are evaluated inmore » a self-consistent way and can be used to evaluate the electrostatic contribution to the thermodynamic properties of a polar fluid. In conclusion, our theory is applied to a dipolar hard sphere fluid as well as interaction site models of polar fluids such as water, where the electrostatic contribution to their thermodynamic properties can be obtained accurately.« less

A molecular Debye-Huckel theory of solvation in polar fluids: An extension of the Born model

DOE PAGES

Xiao, Tiejun; Song, Xueyu

2017-12-06

A dielectric response theory of solvation beyond the conventional Born model for polar fluids is presented. The dielectric response of a polar fluid is described by a Born response mode and a linear combination of Debye-Hückel-like response modes that capture the nonlocal response of polar fluids. The Born mode is characterized by a bulk dielectric constant, while a Debye-Hückel mode is characterized by its corresponding Debye screening length. Both the bulk dielectric constant and the Debye screening lengths are determined from the bulk dielectric function of the polar fluid. The linear combination coefficients of the response modes are evaluated inmore » a self-consistent way and can be used to evaluate the electrostatic contribution to the thermodynamic properties of a polar fluid. In conclusion, our theory is applied to a dipolar hard sphere fluid as well as interaction site models of polar fluids such as water, where the electrostatic contribution to their thermodynamic properties can be obtained accurately.« less

A molecular Debye-Hückel theory of solvation in polar fluids: An extension of the Born model

NASA Astrophysics Data System (ADS)

Xiao, Tiejun; Song, Xueyu

2017-12-01

A dielectric response theory of solvation beyond the conventional Born model for polar fluids is presented. The dielectric response of a polar fluid is described by a Born response mode and a linear combination of Debye-Hückel-like response modes that capture the nonlocal response of polar fluids. The Born mode is characterized by a bulk dielectric constant, while a Debye-Hückel mode is characterized by its corresponding Debye screening length. Both the bulk dielectric constant and the Debye screening lengths are determined from the bulk dielectric function of the polar fluid. The linear combination coefficients of the response modes are evaluated in a self-consistent way and can be used to evaluate the electrostatic contribution to the thermodynamic properties of a polar fluid. Our theory is applied to a dipolar hard sphere fluid as well as interaction site models of polar fluids such as water, where the electrostatic contribution to their thermodynamic properties can be obtained accurately.

A molecular Debye-Hückel theory of solvation in polar fluids: An extension of the Born model.

PubMed

Xiao, Tiejun; Song, Xueyu

2017-12-07

A dielectric response theory of solvation beyond the conventional Born model for polar fluids is presented. The dielectric response of a polar fluid is described by a Born response mode and a linear combination of Debye-Hückel-like response modes that capture the nonlocal response of polar fluids. The Born mode is characterized by a bulk dielectric constant, while a Debye-Hückel mode is characterized by its corresponding Debye screening length. Both the bulk dielectric constant and the Debye screening lengths are determined from the bulk dielectric function of the polar fluid. The linear combination coefficients of the response modes are evaluated in a self-consistent way and can be used to evaluate the electrostatic contribution to the thermodynamic properties of a polar fluid. Our theory is applied to a dipolar hard sphere fluid as well as interaction site models of polar fluids such as water, where the electrostatic contribution to their thermodynamic properties can be obtained accurately.

On Study of Air/Space-borne Dual-Wavelength Radar for Estimates of Rain Profiles

NASA Technical Reports Server (NTRS)

Liao, Liang; Meneghini, Robert

2004-01-01

In this study, a framework is discussed to apply air/space-borne dual-wavelength radar for the estimation of characteristic parameters of hydrometeors. The focus of our study is on the Global Precipitation Measurements (GPM) precipitation radar, a dual-wavelength radar that operates at Ku (13.8 GHz) and Ka (35 GHz) bands. As the droplet size distributions (DSD) of rain are expressed as the Gamma function, a procedure is described to derive the median volume diameter (D(sub 0)) and particle number concentration (N(sub T)) of rain. The correspondences of an important quantity of dual-wavelength radar, defined as deferential frequency ratio (DFR), to the D(sub 0) in the melting region are given as a function of the distance from the 0 C isotherm. A self-consistent iterative algorithm that shows a promising to account for rain attenuation of radar and infer the DSD without use of surface reference technique (SRT) is examined by applying it to the apparent radar reflectivity profiles simulated from the DSD model and then comparing the estimates with the model (true) results. For light to moderate rain the self-consistent rain profiling approach converges to unique and correct solutions only if the same shape factors of Gamma functions are used both to generate and retrieve the rain profiles, but does not converges to the true solutions if the DSD form is not chosen correctly. To further examine the dual-wavelength techniques, the self-consistent algorithm, along with forward and backward rain profiling algorithms, is then applied to the measurements taken from the 2nd generation Precipitation Radar (PR-2) built by Jet Propulsion Laboratory. It is found that rain profiles estimated from the forward and backward approaches are not sensitive to shape factor of DSD Gamma distribution, but the self-consistent method is.

Migration Selection, Protection, and Acculturation in Health: A Binational Perspective on Older Adults

PubMed Central

Riosmena, Fernando; Wong, Rebeca; Palloni, Alberto

2012-01-01

In this article, we test for four potential explanations of the Hispanic Health Paradox (HHP): the “salmon bias,” emigration selection, and sociocultural protection originating in either destination or sending country. To reduce biases related to attrition by return migration typical of most U.S.-based surveys, we combine data from the Mexican Health and Aging Study in Mexico and the U.S. National Health Interview Survey to compare self-reported diabetes, hypertension, current smoking, obesity, and self-rated health among Mexican-born men ages 50 and older according to their previous U.S. migration experience, and U.S.-born Mexican Americans and non-Hispanic whites. We also use height, a measure of health during childhood, to bolster some of our tests. We find an immigrant advantage relative to non-Hispanic whites in hypertension and, to a lesser extent, obesity. We find evidence consistent with emigration selection and the salmon bias in height, hypertension, and self-rated health among immigrants with less than 15 years of experience in the United States; we do not find conclusive evidence consistent with sociocultural protection mechanisms. Finally, we illustrate that although ignoring return migrants when testing for the HHP and its mechanisms, as well as for the association between U.S. experience and health, exaggerates these associations, they are not fully driven by return migration-related attrition. PMID:23192395

Diagrammatic expansion for positive spectral functions beyond GW: Application to vertex corrections in the electron gas

NASA Astrophysics Data System (ADS)

Stefanucci, G.; Pavlyukh, Y.; Uimonen, A.-M.; van Leeuwen, R.

2014-09-01

We present a diagrammatic approach to construct self-energy approximations within many-body perturbation theory with positive spectral properties. The method cures the problem of negative spectral functions which arises from a straightforward inclusion of vertex diagrams beyond the GW approximation. Our approach consists of a two-step procedure: We first express the approximate many-body self-energy as a product of half-diagrams and then identify the minimal number of half-diagrams to add in order to form a perfect square. The resulting self-energy is an unconventional sum of self-energy diagrams in which the internal lines of half a diagram are time-ordered Green's functions, whereas those of the other half are anti-time-ordered Green's functions, and the lines joining the two halves are either lesser or greater Green's functions. The theory is developed using noninteracting Green's functions and subsequently extended to self-consistent Green's functions. Issues related to the conserving properties of diagrammatic approximations with positive spectral functions are also addressed. As a major application of the formalism we derive the minimal set of additional diagrams to make positive the spectral function of the GW approximation with lowest-order vertex corrections and screened interactions. The method is then applied to vertex corrections in the three-dimensional homogeneous electron gas by using a combination of analytical frequency integrations and numerical Monte Carlo momentum integrations to evaluate the diagrams.

Topics in electron capture by fast ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsin, S.H.

1987-01-01

The post-collision interaction (PCI) model was applied, together with the eikonal approximation, to study the (n = 2,3) capture cross sections in p + H(ls) collisions. The results indeed improve the previous eikonal calculations for l = 0 cases, and agree quite well with present experimental data. Calculations using the strong-potential Born (SPB) approximation, with the Sil and McGuire technique, for capture into the np, nd levels are also presented. While these cross sections are smaller than cross sections for capture into the ns levels at high velocities, nevertheless the Thomas peak is clearly evident in both the absolute valuemore » m = 2, absolute value m = 1 and m = 0 magnetic substates in p + H(ls) collisions. Also calculated were corrections to the SPB using the Distorted-Wave Born formalism of Taulbjerg and Briggs. In the sense of a plane-wave Born expansion, all terms of the third Born approximation and all single switching fourth Born terms are included, but a peaking approximation is needed to reduce the calculation to tractable form. Effects of the higher terms are most visible in the valley between the Thomas peak and the forward peak. The Thomas peak is visible in the correction term, even though it includes no second Born contributions.« less

Onsets of hierarchy truncation and self–consistent Born approximation with quantum mechanics prescriptions invariance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Hou-Dao; Yan, YiJing, E-mail: yyan@ust.hk; iChEM and Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026

2015-12-07

The issue of efficient hierarchy truncation is related to many approximate theories. In this paper, we revisit this issue from both the numerical efficiency and quantum mechanics prescription invariance aspects. The latter requires that the truncation approximation made in Schrödinger picture, such as the quantum master equations and their self–consistent–Born–approximation improvements, should be transferable to their Heisenberg–picture correspondences, without further approximations. We address this issue with the dissipaton equation of motion (DEOM), which is a unique theory for the dynamics of not only reduced systems but also hybrid bath environments. We also highlight the DEOM theory is not only aboutmore » how its dynamical variables evolve in time, but also the underlying dissipaton algebra. We demonstrate this unique feature of DEOM with model systems and report some intriguing nonlinear Fano interferences characteristics that are experimentally measurable.« less

An integrated model to simulate the scattering of ultrasounds by inclusions in steels.

PubMed

Darmon, Michel; Calmon, Pierre; Bèle, Bertrand

2004-04-01

We present a study performed to model and predict the ultrasonic response of alumina inclusions in steels. The Born and the extended quasistatic approximations have been applied and modified to improve their accuracy in the framework of this application. The modified Born approximation, called "doubly distorted wave (D(2)W) Born approximation" allowing to deal with various inclusion shapes, has been selected to be implemented in the CIVA software. The model reliability has been evaluated by comparison with Ying and Truell's exact analytical solution. In parallel, measurements have been carried out upon both natural and artificial alumina inclusions.

U.S.-born compared to non-U.S.-born abused women: analysis of baseline data.

PubMed

Montalvo-Liendo, Nora; Koci, Anne; McFarlane, Judith; Gilroy, Heidi; Maddoux, John

2013-01-01

It is evident from recent studies that a woman's citizenship status does not exempt her from exposure to partner violence. The purpose of this article was to examine if social support, self-efficacy, and marginalization of abused women differ based on U.S. born compared to non-U.S. born with and without documentation. The findings suggest that women who were born in the United States had significantly higher self-efficacy scores compared to non-U.S.-born women without documents. There were no significant differences in social support among abused women who are U.S. born compared to non-U.S. born with and without documentation. In addition, women who were not born in the United States and did not have documents had higher marginalization.

Using Trait-State Models to Evaluate the Longitudinal Consistency of Global Self-Esteem From Adolescence to Adulthood.

PubMed

Donnellan, M Brent; Kenny, David A; Trzesniewski, Kali H; Lucas, Richard E; Conger, Rand D

2012-12-01

The present research used a latent variable trait-state model to evaluate the longitudinal consistency of self-esteem during the transition from adolescence to adulthood. Analyses were based on ten administrations of the Rosenberg Self-Esteem scale (Rosenberg, 1965) spanning the ages of approximately 13 to 32 for a sample of 451 participants. Results indicated that a completely stable trait factor and an autoregressive trait factor accounted for the majority of the variance in latent self-esteem assessments, whereas state factors accounted for about 16% of the variance in repeated assessments of latent self-esteem. The stability of individual differences in self-esteem increased with age consistent with the cumulative continuity principle of personality development.

Using Trait-State Models to Evaluate the Longitudinal Consistency of Global Self-Esteem From Adolescence to Adulthood

PubMed Central

Donnellan, M. Brent; Kenny, David A.; Trzesniewski, Kali H.; Lucas, Richard E.; Conger, Rand D.

2012-01-01

The present research used a latent variable trait-state model to evaluate the longitudinal consistency of self-esteem during the transition from adolescence to adulthood. Analyses were based on ten administrations of the Rosenberg Self-Esteem scale (Rosenberg, 1965) spanning the ages of approximately 13 to 32 for a sample of 451 participants. Results indicated that a completely stable trait factor and an autoregressive trait factor accounted for the majority of the variance in latent self-esteem assessments, whereas state factors accounted for about 16% of the variance in repeated assessments of latent self-esteem. The stability of individual differences in self-esteem increased with age consistent with the cumulative continuity principle of personality development. PMID:23180899

Technique for evaluation of the strong potential Born approximation for electron capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sil, N.C.; McGuire, J.H.

1985-04-01

A technique is presented for evaluating differential cross sections in the strong potential Born (SPB) approximation. Our final expression is expressed as a finite sum of one-dimensional integrals, expressible as a finite sum of derivatives of hypergeometric functions.

Self-Reported Health Status in Primary Health Care: The Influence of Immigration and Other Associated Factors

PubMed Central

Salinero-Fort, Miguel Á.; Jiménez-García, Rodrigo; del Otero-Sanz, Laura; de Burgos-Lunar, Carmen; Chico-Moraleja, Rosa M.; Martín-Madrazo, Carmen; Gómez-Campelo, Paloma

2012-01-01

Objective The aims of this study are to compare self-reported health status between Spanish-born and Latin American-born Spanish residents, adjusted by length of residence in the host country; and additionally, to analyse sociodemographic and psychosocial variables associated with a better health status. Design This is a cross-sectional population based study of Latin American-born (n = 691) and Spanish-born (n = 903) in 15 urban primary health care centres in Madrid (Spain), carried out between 2007 and 2009. The participants provided information, through an interview, about self-reported health status, socioeconomic characteristics, psychosocial factors and migration conditions. Descriptive and multiple logistic regression analyses were conducted. Results The Spanish-born participants reported a better health status than the Latin America-born participants (79.8% versus 69.3%, p<0.001). Different patterns of self-reported health status were observed depending on the length of residence in the host country. The proportion of immigrants with a better health status is greater in those who have been in Spain for less than five years compared to those who have stayed longer. Better health status is significantly associated with being men, under 34 years old, being Spanish-born, having a monthly incomes of over 1000 euros, and having considerable social support and low stress. Conclusions Better self-reported health status is associated with being Spanish-born, men, under 34 years old, having an uppermiddle-socioeconomic status, adequate social support, and low stress. Additionally, length of residence in the host country is seen as a related factor in the self-reported health status of immigrants. PMID:22675564

Use of self-heating gel mattresses eliminates admission hypothermia in infants born below 28 weeks gestation.

PubMed

Ibrahim, C P Hafis; Yoxall, C W

2010-07-01

Hypothermia at birth is strongly associated with mortality and morbidity in pre-term infants. A local audit showed limited effectiveness of occlusive wrapping in preventing admission hypothermia in very pre-term infants. Self-heating acetate gel mattresses were introduced as a result to prevent hypothermia at birth in infants born at or below 28 weeks gestation. A retrospective audit was conducted to evaluate the effectiveness of self-heating acetate gel mattresses at resuscitation of infants born at or below 28 weeks to prevent hypothermia at birth. All infants born at or below 28 weeks gestation during 18 months before and 18 months after self-heating acetate gel mattresses were introduced during resuscitation were included. One hundred five babies were born when acetate gel mattresses were not used, and 124 were born during the period when they were. Four (3.3%) babies were hypothermic (temperature <36 degrees C) at admission when the mattresses were used compared to 21 (22.6%) babies who were hypothermic during the period it was not (p < 0.001). Hyperthermia (temperature >37 degrees C) rose from 30.1% prior to use of gel mattresses to 49.6% when they were used (p = 0.004). Self-heating acetate gel mattresses are highly effective in reducing admission hypothermia in infants born at or below 28 weeks gestation. The use of these mattresses is associated with a significant increase in hyperthermia.

Analytic approximation for random muffin-tin alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mills, R.; Gray, L.J.; Kaplan, T.

1983-03-15

The methods introduced in a previous paper under the name of ''traveling-cluster approximation'' (TCA) are applied, in a multiple-scattering approach, to the case of a random muffin-tin substitutional alloy. This permits the iterative part of a self-consistent calculation to be carried out entirely in terms of on-the-energy-shell scattering amplitudes. Off-shell components of the mean resolvent, needed for the calculation of spectral functions, are obtained by standard methods involving single-site scattering wave functions. The single-site TCA is just the usual coherent-potential approximation, expressed in a form particularly suited for iteration. A fixed-point theorem is proved for the general t-matrix TCA, ensuringmore » convergence upon iteration to a unique self-consistent solution with the physically essential Herglotz properties.« less

Probing multi-scale self-similarity of tissue structures using light scattering spectroscopy: prospects in pre-cancer detection

NASA Astrophysics Data System (ADS)

Chatterjee, Subhasri; Das, Nandan K.; Kumar, Satish; Mohapatra, Sonali; Pradhan, Asima; Panigrahi, Prasanta K.; Ghosh, Nirmalya

2013-02-01

Multi-resolution analysis on the spatial refractive index inhomogeneities in the connective tissue regions of human cervix reveals clear signature of multifractality. We have thus developed an inverse analysis strategy for extraction and quantification of the multifractality of spatial refractive index fluctuations from the recorded light scattering signal. The method is based on Fourier domain pre-processing of light scattering data using Born approximation, and its subsequent analysis through Multifractal Detrended Fluctuation Analysis model. The method has been validated on several mono- and multi-fractal scattering objects whose self-similar properties are user controlled and known a-priori. Following successful validation, this approach has initially been explored for differentiating between different grades of precancerous human cervical tissues.

Self-Other Differentiation and the Mother-Child Relationship: The Effects of Sex and Birth Order.

PubMed

Olver, Rose R; Aries, Elizabeth; Batgos, Joanna

1989-09-01

We examined the effect of sex and birth order on the experience of a separate sense of self and its connection to mothers' differential involvement with sons and daughters. Results from two samples of college-age students are reported. Men showed a more separate sense of self than women, and mothers were reported to be more highly involved with and intrusive in the lives of their daughters than their sons. Results for birth order were consistent though not always statistically significant: First-born women had the least separate sense of self and reported the greatest degree of maternal involvement and intrusiveness. Implications of these findings for developmental theory and criteria of Psychological well-being are discussed.

Balloon-borne radiometer measurements of Northern Hemisphere mid-latitude stratospheric HNO3 profiles spanning 12 years

NASA Astrophysics Data System (ADS)

Toohey, M.; Quine, B. M.; Strong, K.; Bernath, P. F.; Boone, C. D.; Jonsson, A. I.; McElroy, C. T.; Walker, K. A.; Wunch, D.

2007-12-01

Low-resolution atmospheric thermal emission spectra collected by balloon-borne radiometers over the time span of 1990-2002 are used to retrieve vertical profiles of HNO3, CFC-11 and CFC-12 volume mixing ratios between approximately 10 and 35 km altitude. All of the data analyzed have been collected from launches from a Northern Hemisphere mid-latitude site, during late summer, when stratospheric dynamic variability is at a minimum. The retrieval technique incorporates detailed forward modeling of the instrument and the radiative properties of the atmosphere, and obtains a best fit between modeled and measured spectra through a combination of onion-peeling and optimization steps. The retrieved HNO3 profiles are consistent over the 12-year period, and are consistent with recent measurements by the Atmospheric Chemistry Experiment-Fourier transform spectrometer satellite instrument. We therefore find no evidence of long-term changes in the HNO3 summer mid-latitude profile, although the uncertainty of our measurements precludes a conclusive trend analysis.

Balloon-borne radiometer measurement of Northern Hemisphere mid-latitude stratospheric HNO3 profiles spanning 12 years

NASA Astrophysics Data System (ADS)

Toohey, M.; Quine, B. M.; Strong, K.; Bernath, P. F.; Boone, C. D.; Jonsson, A. I.; McElroy, C. T.; Walker, K. A.; Wunch, D.

2007-08-01

Low-resolution atmospheric thermal emission spectra collected by balloon-borne radiometers over the time span of 1990-2002 are used to retrieve vertical profiles of HNO3, CFC-11 and CFC-12 volume mixing ratios between approximately 10 and 35 km altitude. All of the data analyzed have been collected from launches from a Northern Hemisphere mid-latitude site, during late summer, when stratospheric dynamic variability is at a minimum. The retrieval technique incorporates detailed forward modeling of the instrument and the radiative properties of the atmosphere, and obtains a best fit between modeled and measured spectra through a combination of onion-peeling and global optimization steps. The retrieved HNO3 profiles are consistent over the 12-year period, and are consistent with recent measurements by the Atmospheric Chemistry Experiment-Fourier transform spectrometer satellite instrument. This suggests that, to within the errors of the 1990 measurements, there has been no significant change in the HNO3 summer mid-latitude profile.

Parenting Effects on Self-Efficacy and Self-Esteem in Late Adolescence and How Those Factors Impact Adjustment to College

ERIC Educational Resources Information Center

Smith, Gregory J

2007-01-01

Approximately three months before starting college, 203 high school seniors completed a questionnaire consisting of the General Self-Efficacy Scale, the Rosenberg Self-Esteem Scale, and the Parental Authority Questionnaire (PAQ) assessing their parents' parenting styles. The PAQ yielded scores on three parenting styles originally proposed by…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Afonso, V.I.; Olmo, Gonzalo J.; Rubiera-Garcia, D., E-mail: viafonso@df.ufcg.edu.br, E-mail: gonzalo.olmo@uv.es, E-mail: drgarcia@fc.ul.pt

The existence of static, spherically symmetric, self-gravitating scalar field solutions in the context of Born-Infeld gravity is explored. Upon a combination of analytical approximations and numerical methods, the equations for a free scalar field (without a potential term) are solved, verifying that the solutions recover the predictions of General Relativity far from the center but finding important new effects in the central regions. We find two classes of objects depending on the ratio between the Schwarzschild radius and a length scale associated to the Born-Infeld theory: massive solutions have a wormhole structure, with their throat at r ≈ 2 Mmore » , while for the lighter configurations the topology is Euclidean. The total energy density of these solutions exhibits a solitonic profile with a maximum peaked away from the center, and located at the throat whenever a wormhole exists. The geodesic structure and curvature invariants are analyzed for the various configurations considered.« less

Persistence length of wormlike micelles composed of ionic surfactants: self-consistent-field predictions.

PubMed

Lauw, Y; Leermakers, F A M; Stuart, M A Cohen

2007-07-19

The persistence length of a wormlike micelle composed of ionic surfactants C(n)E(m)X(k) in an aqueous solvent is predicted by means of the self-consistent-field theory where C(n)E(m) is the conventional nonionic surfactant and X(k) is an additional sequence of k weakly charged (pH-dependent) segments. By considering a toroidal micelle at infinitesimal curvature, we evaluate the bending modulus of the wormlike micelle that corresponds to the total persistence length, consisting of an elastic/intrinsic and an electrostatic contribution. The total persistence length increases with pH and decreases with increasing background salt concentration. We estimate that the electrostatic persistence length l(p,e)(0) scales with respect to the Debye length kappa(-1) as l(p,e)(0) approximately kappa(-p) where p approximately 1.98 for wormlike micelles consisting of C(20)E(10)X(1) surfactants and p approximately 1.54 for wormlike micelles consisting of C(20)E(10)X(2) surfactants. The total persistence length l(p,t)(0) is a weak function of the head group length m but scales with the tail length n as l(p,t)(0) approximately n(x) where x approximately 2-2.6, depending on the corresponding head group length. Interestingly, l(p,t)(0) varies nonmonotonically with the number of charged groups k due to the opposing trends in the electrostatic and elastic bending rigidities upon variation of k.

Women in Free Clinics: An Assessment of Health-Related Quality of Life for Prevention and Health Education.

PubMed

Kamimura, Akiko; Myers, Kyl; Ashby, Jeanie; Trinh, Ha Ngoc; Nourian, Maziar M; Reel, Justine J

2015-08-01

Understanding gender influences on health-related quality of life (HRQoL) is important to improve women's health when considering diseases that afflict women specifically. The target population of this study was uninsured female free clinic patients who are low socio-economic status and lack access to healthcare resources. Free clinics provide free or reduced fee healthcare to individuals who lack access to primary care and are socio-economically disadvantaged. While approximately half of free clinic patients are women, there is a paucity of comprehensive health-related data for female free clinic patients. US born English, non-US born English, and Spanish speaking female free clinic patients completed a self-administered survey using a standardized women's HRQoL measure in Fall 2014 (N = 389). Female free clinic patients reported lower HRQoL on all aspects of women's health compared to the US baseline scores, and were less likely to utilize preventive care including: mammograms, Pap smear, and HPV vaccination compared to the US general population. Spanish speakers reported a higher percentage of having had mammography and Pap smear, and heard about HPV compared to the other two groups. US born English speakers reported lower levels of HRQoL in vasomotor symptoms and sleep symptoms, and the lowest percentage of breast health and Pap smear screenings compared to non-US born English and Spanish speakers. Non-US born English speakers reported higher preference for female physician compared to US born English speakers and Spanish speakers. Free clinic female patients need preventative interventions and educational opportunities to improve their overall HRQoL.

Isoscalar and isovector giant resonances in a self-consistent phonon coupling approach

NASA Astrophysics Data System (ADS)

Lyutorovich, N.; Tselyaev, V.; Speth, J.; Krewald, S.; Grümmer, F.; Reinhard, P.-G.

2015-10-01

We present fully self-consistent calculations of isoscalar giant monopole and quadrupole as well as isovector giant dipole resonances in heavy and light nuclei. The description is based on Skyrme energy-density functionals determining the static Hartree-Fock ground state and the excitation spectra within random-phase approximation (RPA) and RPA extended by including the quasiparticle-phonon coupling at the level of the time-blocking approximation (TBA). All matrix elements were derived consistently from the given energy-density functional and calculated without any approximation. As a new feature in these calculations, the single-particle continuum was included thus avoiding the artificial discretization usually implied in RPA and TBA. The step to include phonon coupling in TBA leads to small, but systematic, down shifts of the centroid energies of the giant resonances. These shifts are similar in size for all Skyrme parametrizations investigated here. After all, we demonstrate that one can find Skyrme parametrizations which deliver a good simultaneous reproduction of all three giant resonances within TBA.

L-shell x-ray production cross sections of Ni, Cu, Ge, As, Rb, Sr, Y, Zr, and Pd by (0. 25--2. 5)-MeV protons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duggan, J.L.; Kocur, P.M.; Price, J.L.

1985-10-01

L-shell x-ray production cross sections by /sub 1//sup 1/H/sup +/ ions are reported. The data are compared to the first Born approximation (plane-wave Born approximation for direct ionization and Oppenheimer-Brinkman-Kramers approximation for electron capture) and to the ECPSSR (energy-loss and Coulomb-deflection effects, perturbed stationary-state approximation with relativistic correction) theory. The energy of the protons ranged from 0.25 to 2.5 MeV in steps of 0.25 MeV. The targets used in these measurements were /sub 28/Ni, /sub 29/Cu, /sub 32/Ge, /sub 33/As, /sub 37/Rb, /sub 38/Sr, /sub 39/Y, /sub 40/Zr, and /sub 46/Pd. The first Born theory generally agrees with the datamore » found in the literature at high energies and overpredicts them below 1.5 MeV. The ECPSSR predictions are in better agreement with experimental cross sections. At 0.25 MeV our data, however, are underestimated by this theory and tend to agree with the first Born approximation.« less

Calculation of Protein Heat Capacity from Replica-Exchange Molecular Dynamics Simulations with Different Implicit Solvent Models

DTIC Science & Technology

2008-10-30

rigorous Poisson-based methods generally apply a Lee-Richards mo- lecular surface.9 This surface is considered the de facto description for continuum...definition and calculation of the Born radii. To evaluate the Born radii, two approximations are invoked. The first is the Coulomb field approximation (CFA...energy term, and depending on the particular GB formulation, higher-order non- Coulomb correction terms may be added to the Born radii to account for the

First Encounter: A Child Is Born, a Self Is Born.

ERIC Educational Resources Information Center

Roeper, Annemarie

1995-01-01

This article considers the very early development of a self in the infant and young child, using theories of Sigmund Freud. The vital role of relationships, especially the mother-child relationship, for the developing self is stressed. Stages of learning trust and inner controls are also addressed. (DB)

πN scattering and γN → Nπ photoproduction within the unitary improved Born approximation

NASA Astrophysics Data System (ADS)

Mariano, A.

2007-07-01

Following the programme of describing consistently several processes where the isobar Δ(1232 MeV) nucleon resonance appears as an intermediate state, in this work we propose to unitarize our old improved Born approximation already used to describe successfully π+p elastic and radiative scattering, to treat pion photoproduction. First we add the effect of final state interactions and make a new determination of the mass, width and the coupling constant to the pion-nucleon state of the Δ resonance. Then extending the model for pion photoproduction and using the resonance parameters determined previously, we are able to define effective form factors (at k2γ = 0) for the γN → Δ vertex with values GM = 2.97 ± 0.08 and GE = 0.055 ± 0.010, by fitting the data for the M3/21+ and E3/21+ multipoles. These values are fully consistent with recent chiral effective field theory calculations, and using them we can predict satisfactorily the data for other multipoles and the photoproduction cross section. Finally, we intend a model-independent determination of the bare form factors making a dynamical dressing of the vertex, getting G0M = 1.69 ± 0.02, G0E = 0.028 ± 0.008 and R0EM = -1.67 ± 0.45%, which are compared with different quark models.

Low-density homogeneous symmetric nuclear matter: Disclosing dinucleons in coexisting phases

NASA Astrophysics Data System (ADS)

Arellano, Hugo F.; Delaroche, Jean-Paul

2015-01-01

The effect of in-medium dinucleon bound states on self-consistent single-particle fields in Brueckner, Bethe and Goldstone theory is investigated in symmetric nuclear matter at zero temperature. To this end, dinucleon bound state occurences in the 1 S 0 and 3 SD 1 channels are explicitly accounted for --within the continuous choice for the auxiliary fields-- while imposing self-consistency in Brueckner-Hartree-Fock approximation calculations. Searches are carried out at Fermi momenta in the range fm-1, using the Argonne bare nucleon-nucleon potential without resorting to the effective-mass approximation. As a result, two distinct solutions meeting the self-consistency requirement are found with overlapping domains in the interval 0.130 fm-1 0.285 fm-1, corresponding to mass densities between and g cm-3. Effective masses as high as three times the nucleon mass are found in the coexistence domain. The emergence of superfluidity in relationship with BCS pairing gap solutions is discussed.

Personal and cultural influences on diabetes self-care behaviors among older Hispanics born in the U.S. and Mexico.

PubMed

Mier, Nelda; Smith, Matthew Lee; Carrillo-Zuniga, Genny; Wang, Xiaohui; Garza, Norma; Ory, Marcia G

2012-12-01

Older Hispanics are disproportionately affected by diabetes, but little is known about predictors of diabetes self-care among this group. This study compared the magnitude of three self-care behaviors (diet, physical activity (PA), and glucose monitoring) among older Hispanics with type 2 diabetes born in the United States (n = 59) to those born in Mexico (n = 179), and investigated the influence of personal and health indicators on each self-care behavior. Findings were based on data drawn from convenience sample data collected with a questionnaire. Self-care behaviors were moderately practiced (39.5-45.8 %) with no significant differences by nativity. Mexico-born seniors were less linguistically acculturated (P < 0.001). Being female (OR = 2.41) and PA levels (OR = 2.62) were significantly associated with diet. Being female (OR = 3.24), more educated (OR = 3.73), U.S.-born (OR = 2.84), and receiving diabetes education (OR = 3.67) were associated with PA. Diabetes education (OR = 2.41) was associated with glucose monitoring. Although acculturation influenced only PA and no other behaviors, personal and cultural factors require further investigation to design diabetes management strategies for Hispanic seniors at the border region.

Educational mismatch and health status among foreign-born workers in Sweden.

PubMed

Dunlavy, A C; Garcy, A M; Rostila, M

2016-04-01

Foreign-born workers have been shown to experience poorer working conditions than native-born workers. Yet relationships between health and educational mismatch have been largely overlooked among foreign-born workers. This study uses objective and self-reported measures of educational mismatch to compare the prevalence of educational mismatch among native (n = 2359) and foreign-born (n = 1789) workers in Sweden and to examine associations between educational mismatch and poor self-rated health. Findings from weighted multivariate logistic regression which controlled for social position and individual-level demographic characteristics suggested that over-educated foreign-born workers had greater odds ratios for poor-self rated health compared to native-born matched workers. This association was particularly evident among men (OR = 2.14, 95% CI: 1.04-4.39) and women (OR = 2.13, 95% CI: 1.12-4.03) from countries outside of Western Europe, North America, and Australia/New Zealand. Associations between under-education and poor-self rated health were also found among women from countries outside of Western Europe, North America, and Australia/New Zealand (OR = 2.02, 95% CI: 1.27-3.18). These findings suggest that educational mismatch may be an important work-related social determinant of health among foreign-born workers. Future studies are needed to examine the effects of long-term versus short-term states of educational mismatch on health and to study relationships over time. Copyright © 2016 Elsevier Ltd. All rights reserved.

Potential-Energy Surfaces, the Born-Oppenheimer Approximations, and the Franck-Condon Principle: Back to the Roots.

PubMed

Mustroph, Heinz

2016-09-05

The concept of a potential-energy surface (PES) is central to our understanding of spectroscopy, photochemistry, and chemical kinetics. However, the terminology used in connection with the basic approximations is variously, and somewhat confusingly, represented with such phrases as "adiabatic", "Born-Oppenheimer", or "Born-Oppenheimer adiabatic" approximation. Concerning the closely relevant and important Franck-Condon principle (FCP), the IUPAC definition differentiates between a classical and quantum mechanical formulation. Consequently, in many publications we find terms such as "Franck-Condon (excited) state", or a vertical transition to the "Franck-Condon point" with the "Franck-Condon geometry" that relaxes to the excited-state equilibrium geometry. The Born-Oppenheimer approximation and the "classical" model of the Franck-Condon principle are typical examples of misused terms and lax interpretations of the original theories. In this essay, we revisit the original publications of pioneers of the PES concept and the FCP to help stimulate a lively discussion and clearer thinking around these important concepts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Axions and SN1987A

NASA Technical Reports Server (NTRS)

Burrows, Adam; Turner, Michael S.; Brinkmann, R. P.

1988-01-01

The effect of free-streaming axion emission on numerical models for the cooling of the newly born neutron star associated with SN1987A is considered. It is found that for an axion mass of greater than approximately 10 to the -3 eV, axion emission shortens the duration of the expected neutrino burst so significantly that it would be inconsistent with the neutrino observations made by the Kamiokande II and Irvine-Michigan-Brookhaven detectors. However, the possibility has not been investigated that axion trapping (which should occur for masses greater than or equal to 0.02 eV) sufficiently reduces axion emission so that axion masses greater than approximately 2 eV would be consistent with the neutrino observations.

Validity of virial theorem in all-electron mixed basis density functional, Hartree–Fock, and GW calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuwahara, Riichi; Accelrys K. K., Kasumigaseki Tokyu Building 17F, 3-7-1 Kasumigaseki, Chiyoda-ku, Tokyo 100-0013; Tadokoro, Yoichi

In this paper, we calculate kinetic and potential energy contributions to the electronic ground-state total energy of several isolated atoms (He, Be, Ne, Mg, Ar, and Ca) by using the local density approximation (LDA) in density functional theory, the Hartree–Fock approximation (HFA), and the self-consistent GW approximation (GWA). To this end, we have implemented self-consistent HFA and GWA routines in our all-electron mixed basis code, TOMBO. We confirm that virial theorem is fairly well satisfied in all of these approximations, although the resulting eigenvalue of the highest occupied molecular orbital level, i.e., the negative of the ionization potential, is inmore » excellent agreement only in the case of the GWA. We find that the wave function of the lowest unoccupied molecular orbital level of noble gas atoms is a resonating virtual bound state, and that of the GWA spreads wider than that of the LDA and thinner than that of the HFA.« less

Density-functional energy gaps of solids demystified

NASA Astrophysics Data System (ADS)

Perdew, John P.; Ruzsinszky, Adrienn

2018-06-01

The fundamental energy gap of a solid is a ground-state second energy difference. Can one find the fundamental gap from the gap in the band structure of Kohn-Sham density functional theory? An argument of Williams and von Barth (WB), 1983, suggests that one can. In fact, self-consistent band-structure calculations within the local density approximation or the generalized gradient approximation (GGA) yield the fundamental gap within the same approximation for the energy. Such a calculation with the exact density functional would yield a band gap that also underestimates the fundamental gap, because the exact Kohn-Sham potential in a solid jumps up by an additive constant when one electron is added, and the WB argument does not take this effect into account. The WB argument has been extended recently to generalized Kohn-Sham theory, the simplest way to implement meta-GGAs and hybrid functionals self-consistently, with an exchange-correlation potential that is a non-multiplication operator. Since this operator is continuous, the band gap is again the fundamental gap within the same approximation, but, because the approximations are more realistic, so is the band gap. What approximations might be even more realistic?

Microwave imaging by three-dimensional Born linearization of electromagnetic scattering

NASA Astrophysics Data System (ADS)

Caorsi, S.; Gragnani, G. L.; Pastorino, M.

1990-11-01

An approach to microwave imaging is proposed that uses a three-dimensional vectorial form of the Born approximation to linearize the equation of electromagnetic scattering. The inverse scattering problem is numerically solved for three-dimensional geometries by means of the moment method. A pseudoinversion algorithm is adopted to overcome ill conditioning. Results show that the method is well suited for qualitative imaging purposes, while its capability for exactly reconstructing the complex dielectric permittivity is affected by the limitations inherent in the Born approximation and in ill conditioning.

Stopping relativistic Xe, Ho, Au, and U nuclei in nuclear emulsions

NASA Technical Reports Server (NTRS)

Waddington, C. J.; Fixsen, D. J.; Freier, P. S.

1985-01-01

Nuclei of Xe-54, Ho-67, Au-79 and U-92 accelerated at the Bevalac to energies between 1200 and 900 MeV/n were stopped in nuclear emulsions. The observed residual ranges were compared with those calculated from various models of energy loss and shown to be most consistent with a calculation that includes those higher order correction terms proposed previously to describe the energy loss of highly changed particles, for which the first Born approximation is not valid.

Stopping relativistic Xe, Ho, Au and U nuclei in nuclear emulsions

NASA Technical Reports Server (NTRS)

Waddington, C. J.; Fixsen, D. J.; Freier, P. S.

1985-01-01

Nuclei of Xe-54, Ho-67, Au-79 and U-92 accelerated at the Bevalac to energies between 1200 and 900 MeV/n were stopped in nuclear emulsions. The observed residual ranges were compared with those calculated from various models of energy loss and shown to be most consistent with a calculation that includes those higher order correction terms proposed previously to describe the energy loss of highly charged particles, for which the first Born approximation is not valid.

A balloon measurement of the isotopic composition of galactic cosmic ray boron, carbon and nitrogen. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Zumberge, J. F.

1981-01-01

The isotopic compositions of galactic cosmic ray boron, carbon, and nitrogen were measured at energies near 300 MeV amu, using a balloon-borne instrument at an atmospheric depth of approximately 5 g/sq cm. The calibrations of the detectors comprising the instrument are described. The saturation properties of the cesium iodide scintillators used for measurement of particle energy are studied in the context of analyzing the data for mass. The achieved rms mass resolution varies from approximately 0.3 amu at boron to approximately 0.5 amu at nitrogen, consistent with a theoretical analysis of the contributing factors. Corrected for detector interactions and the effects of the residual atmosphere the results are B-10/B=0.33 (+0.17, -0.11), C-13/C=0.06 (+0.13, -0.11), and N-15/N=0.42 (+0.19, -0.17). A model of galactic propagation and solar modulation is described. Assuming a cosmic ray source composition of solar-like isotopic abundances, the model predicts abundances near Earth consistent with the measurements.

On the mathematical treatment of the Born-Oppenheimer approximation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jecko, Thierry, E-mail: thierry.jecko@u-cergy.fr

2014-05-15

Motivated by the paper by Sutcliffe and Woolley [“On the quantum theory of molecules,” J. Chem. Phys. 137, 22A544 (2012)], we present the main ideas used by mathematicians to show the accuracy of the Born-Oppenheimer approximation for molecules. Based on mathematical works on this approximation for molecular bound states, in scattering theory, in resonance theory, and for short time evolution, we give an overview of some rigorous results obtained up to now. We also point out the main difficulties mathematicians are trying to overcome and speculate on further developments. The mathematical approach does not fit exactly to the common usemore » of the approximation in Physics and Chemistry. We criticize the latter and comment on the differences, contributing in this way to the discussion on the Born-Oppenheimer approximation initiated by Sutcliffe and Woolley. The paper neither contains mathematical statements nor proofs. Instead, we try to make accessible mathematically rigourous results on the subject to researchers in Quantum Chemistry or Physics.« less

Long-term effects on adult attachment in German occupation children born after World War II in comparison with a birth-cohort-matched representative sample of the German general population.

PubMed

Kaiser, Marie; Kuwert, Philipp; Braehler, Elmar; Glaesmer, Heide

2018-02-01

Children born of war are a phenomenon of every conflict. At the end of World War II and thereafter, approximately 400,000 children were fathered by foreign soldiers and born to local women in Germany. Quantitative research on psychosocial consequences of growing up as German occupation child (GOC) has been missing so far. This study examines adult attachment and its association with current depression in GOC (N = 146) using self-report instruments: Adult Attachment Scale, Patient Health Questionnaire. Data were compared to a birth-cohort-matched representative sample of the German population (BCMS; N = 786). GOC differ in both attachment dimensions (less comfortable with closeness/intimacy, lowered ability to depend on others) and adult attachment (more dismissive and fearful) compared to BCMS. Insecure adult attachment is associated with current depression. GOC grew up under difficult circumstances (e.g. poverty, adverse events, and stigmatization). Even decades later they display more insecure attachment in current relationships. Findings underline the complex and long-term impact of their developmental conditions on attachment and current mental health.

Next generation extended Lagrangian first principles molecular dynamics

NASA Astrophysics Data System (ADS)

Niklasson, Anders M. N.

2017-08-01

Extended Lagrangian Born-Oppenheimer molecular dynamics [A. M. N. Niklasson, Phys. Rev. Lett. 100, 123004 (2008)] is formulated for general Hohenberg-Kohn density-functional theory and compared with the extended Lagrangian framework of first principles molecular dynamics by Car and Parrinello [Phys. Rev. Lett. 55, 2471 (1985)]. It is shown how extended Lagrangian Born-Oppenheimer molecular dynamics overcomes several shortcomings of regular, direct Born-Oppenheimer molecular dynamics, while improving or maintaining important features of Car-Parrinello simulations. The accuracy of the electronic degrees of freedom in extended Lagrangian Born-Oppenheimer molecular dynamics, with respect to the exact Born-Oppenheimer solution, is of second-order in the size of the integration time step and of fourth order in the potential energy surface. Improved stability over recent formulations of extended Lagrangian Born-Oppenheimer molecular dynamics is achieved by generalizing the theory to finite temperature ensembles, using fractional occupation numbers in the calculation of the inner-product kernel of the extended harmonic oscillator that appears as a preconditioner in the electronic equations of motion. Material systems that normally exhibit slow self-consistent field convergence can be simulated using integration time steps of the same order as in direct Born-Oppenheimer molecular dynamics, but without the requirement of an iterative, non-linear electronic ground-state optimization prior to the force evaluations and without a systematic drift in the total energy. In combination with proposed low-rank and on the fly updates of the kernel, this formulation provides an efficient and general framework for quantum-based Born-Oppenheimer molecular dynamics simulations.

Next generation extended Lagrangian first principles molecular dynamics.

PubMed

Niklasson, Anders M N

2017-08-07

Extended Lagrangian Born-Oppenheimer molecular dynamics [A. M. N. Niklasson, Phys. Rev. Lett. 100, 123004 (2008)] is formulated for general Hohenberg-Kohn density-functional theory and compared with the extended Lagrangian framework of first principles molecular dynamics by Car and Parrinello [Phys. Rev. Lett. 55, 2471 (1985)]. It is shown how extended Lagrangian Born-Oppenheimer molecular dynamics overcomes several shortcomings of regular, direct Born-Oppenheimer molecular dynamics, while improving or maintaining important features of Car-Parrinello simulations. The accuracy of the electronic degrees of freedom in extended Lagrangian Born-Oppenheimer molecular dynamics, with respect to the exact Born-Oppenheimer solution, is of second-order in the size of the integration time step and of fourth order in the potential energy surface. Improved stability over recent formulations of extended Lagrangian Born-Oppenheimer molecular dynamics is achieved by generalizing the theory to finite temperature ensembles, using fractional occupation numbers in the calculation of the inner-product kernel of the extended harmonic oscillator that appears as a preconditioner in the electronic equations of motion. Material systems that normally exhibit slow self-consistent field convergence can be simulated using integration time steps of the same order as in direct Born-Oppenheimer molecular dynamics, but without the requirement of an iterative, non-linear electronic ground-state optimization prior to the force evaluations and without a systematic drift in the total energy. In combination with proposed low-rank and on the fly updates of the kernel, this formulation provides an efficient and general framework for quantum-based Born-Oppenheimer molecular dynamics simulations.

Dust trap formation in a non-self-sustained discharge with external gas ionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filippov, A. V., E-mail: fav@triniti.ru; Babichev, V. N.; Pal’, A. F.

2015-11-15

Results from numerical studies of a non-self-sustained gas discharge containing micrometer dust grains are presented. The non-self-sustained discharge (NSSD) was controlled by a stationary fast electron beam. The numerical model of an NSSD is based on the diffusion drift approximation for electrons and ions and self-consistently takes into account the influence of the dust component on the electron and ion densities. The dust component is described by the balance equation for the number of dust grains and the equation of motion for dust grains with allowance for the Stokes force, gravity force, and electric force in the cathode sheath. Themore » interaction between dust grains is described in the self-consistent field approximation. The height of dust grain levitation over the cathode is determined and compared with experimental results. It is established that, at a given gas ionization rate and given applied voltage, there is a critical dust grain size above which the levitation condition in the cathode sheath cannot be satisfied. Simulations performed for the dust component consisting of dust grains of two different sizes shows that such grains levitate at different heights, i.e., size separation of dust drains levitating in the cathode sheath of an NSSD takes place.« less

The impact of ethnicity and self-reported health on psychological well-being: a comparative study of Kurdish-born and Swedish-born people.

PubMed

Taloyan, Marina; Sundquist, Jan; Al-Windi, Ahmad

2008-01-01

Although immigrants generally have poorer health and higher psychological distress than the native population, information on Kurdish immigrants' psychological well-being is limited. The aims of the study were to examine the association between ethnicity and poor psychological well-being, and to assess the relationships between socio-demographic characteristics, self-reported health, somatic pain, gastrointestinal complaints and poor psychological well-being. Immigrants with self-reported Kurdish ethnicity (men, n=111; women, n=86) in Sweden from the national sample of immigrants aged 27-60 and 1407 Swedes (1996) were studied. Unconditional logistic regression was performed using the Stata Software program. In the logistic model adjusted for age, sex, employment and self-reported health, the odds ratio for Kurdish-born subjects for having poor psychological well-being is twice as high as for Swedish-born subjects. Subjects with poor self-reported health had more than a threefold higher odds ratio for having poor psychological well-being compared with those with good self-reported health. Furthermore, being female, having somatic pain and recurrent gastrointestinal complaints regardless of ethnicity increased the odds for having poor psychological well-being. Being Kurdish-born and/or reporting poor health in addition to age, female gender, somatic pain and recurrent gastrointestinal complaints is significantly and independently related to poor psychological well-being even when adjusted for all confounders.

South Asian-White health inequalities in Canada: intersections with gender and immigrant status.

PubMed

Veenstra, Gerry; Patterson, Andrew C

2016-12-01

We apply intersectionality theory to health inequalities in Canada by investigating whether South Asian-White health inequalities are conditioned by gender and immigrant status in a synergistic way. Our dataset comprised 10 cycles (2001-2013) of the Canadian Community Health Survey. Using binary logistic regression modeling, we examined South Asian-White inequalities in self-rated health, diabetes, hypertension and asthma before and after controlling for potentially explanatory factors. Models were calculated separately in subsamples of native-born women, native-born men, immigrant women and immigrant men. South Asian immigrants had higher odds of fair/poor self-rated health, diabetes and hypertension than White immigrants. Native-born South Asian men had higher odds of fair/poor self-rated health than native-born White men and native-born South Asian women had lower odds of hypertension than native-born White women. Education, household income, smoking, physical activity and body mass index did little to explain these associations. The three-way interaction between racial identity, gender and immigrant status approached statistical significance for hypertension but not for self-rated health and asthma. Our findings provide modest support for the intersectionally inspired principle that combinations of identities derived from race, gender and nationality constitute sui generis categories in the manifestation of health outcomes.

Approximate solutions of acoustic 3D integral equation and their application to seismic modeling and full-waveform inversion

NASA Astrophysics Data System (ADS)

Malovichko, M.; Khokhlov, N.; Yavich, N.; Zhdanov, M.

2017-10-01

Over the recent decades, a number of fast approximate solutions of Lippmann-Schwinger equation, which are more accurate than classic Born and Rytov approximations, were proposed in the field of electromagnetic modeling. Those developments could be naturally extended to acoustic and elastic fields; however, until recently, they were almost unknown in seismology. This paper presents several solutions of this kind applied to acoustic modeling for both lossy and lossless media. We evaluated the numerical merits of those methods and provide an estimation of their numerical complexity. In our numerical realization we use the matrix-free implementation of the corresponding integral operator. We study the accuracy of those approximate solutions and demonstrate, that the quasi-analytical approximation is more accurate, than the Born approximation. Further, we apply the quasi-analytical approximation to the solution of the inverse problem. It is demonstrated that, this approach improves the estimation of the data gradient, comparing to the Born approximation. The developed inversion algorithm is based on the conjugate-gradient type optimization. Numerical model study demonstrates that the quasi-analytical solution significantly reduces computation time of the seismic full-waveform inversion. We also show how the quasi-analytical approximation can be extended to the case of elastic wavefield.

Da Vincis Children Take Flight: Unmanned Aircraft Systems in the Homeland

DTIC Science & Technology

2014-03-01

corporate self-regulation, consistent with a laissez - faire tradition. B. TOWARD A POLICY OPTION TO PROTECT PRIVACY WHILE MAINTAINING TRANSPARENCY Over...take this journey and shared many a conversation over 4 a.m. coffee; who has borne more than his fair share of the responsibility for our home; and...alternate routes to meet consumer demand.  Public interest is considered, as expressed through political leadership . Public interest will be assumed to

Self-consistent electrostatic potential due to trapped plasma in the magnetosphere

NASA Technical Reports Server (NTRS)

Miller, Ronald H.; Khazanov, George V.

1993-01-01

A steady state solution for the self-consistent electrostatic potential due to a plasma confined in a magnetic flux tube is considered. A steady state distribution function is constructed for the trapped particles from the constants of the motion, in the absence of waves and collisions. Using Liouville's theorem, the particle density along the geomagnetic field is determined and found to depend on the local magnetic field, self-consistent electric potential, and the equatorial plasma distribution function. A hot anisotropic magnetospheric plasma in steady state is modeled by a bi-Maxwellian at the equator. The self-consistent electric potential along the magnetic field is calculated assuming quasineutrality, and the potential drop is found to be approximately equal to the average kinetic energy of the equatorially trapped plasma. The potential is compared with that obtained by Alfven and Faelthammar (1963).

Low-energy Scattering of Positronium by Atoms

NASA Technical Reports Server (NTRS)

Ray, Hasi

2007-01-01

The survey reports theoretical studies involving positronium (Ps) - atom scattering. Investigations carried out in last few decades have been briefly reviewed in this article. A brief description of close-coupling approximation (CCA), the first-Born approximation (FBA) and the Born-Oppenheimer approximation (BOA) for Ps-Atom systems are made. The CCA codes of Ray et a1 [1-6] are reinvestigated using very fine mesh-points to search for resonances. The article advocates the need for an extended basis set & a systematic study using CCAs.

Self-consistent models for Coulomb heated X-ray pulsar atmospheres

NASA Technical Reports Server (NTRS)

Harding, A.; Meszaros, S. P.; Kirk, J.; Galloway, D.

1983-01-01

Calculations of accreting magnetized neutron star atmospheres heated by the gradual deceleration of protons via Coulomb collisions are presented. Self consistent determinations of the temperature and density structure for different accretion rates are made by assuming hydrostatic equilibrium and energy balance, coupled with radiative transfer. The full radiative transfer in two polarizations, using magnetic cross sections but with cyclotron resonance effects treated approximately, is carried out in the inhomogeneous atmospheres.

Prevalence of disability among US- and foreign-born Arab Americans: results from the 2000 US Census.

PubMed

Dallo, Florence J; Al Snih, Soham; Ajrouch, Kristine J

2009-01-01

Although the prevalence of disability for various racial and ethnic groups has been documented, little attention has been paid to Arab Americans in the United States. We estimated the age- and sex-adjusted prevalence of disability among older Arab Americans and examined the association between nativity status and self-reported physical and self-care disability before and after controlling for covariates. We used data from the 5% Public Use Microdata Samples of the 2000 US Census. Our sample included 4,225 individuals 65 years of age and older who identified with an Arab ancestry. Of these, 2,280 were foreign-born and 1,945 were US-born. The age- and sex-adjusted prevalence of having a physical disability was 31.2% for foreign- and 23.4% for US-born older Arab Americans, and the age- and sex- adjusted prevalence of having a self-care disability was 13.5% for foreign- and 6.8% for US-born Arab Americans. Iraqis reported the highest estimates for both disabilities (physical, 36.2%; self-care, 19.8%) compared to other Arab ethnic groups. In the crude model, foreign-born Arab Americans were more likely (OR=1.32; 95% CI=1.28, 1.36) to report a physical disability compared to US-born Arab Americans. When adjusting for English language ability in the final model, the odds of having a physical disability for foreign-born Arab Americans was protective compared to US-born Arab Americans (OR=0.92; 95% CI=0.88, 0.96). In the crude model, foreign-born Arab Americans were 1.82 times (95% CI=1.74, 1.90) more likely to report a self-care disability compared to US-born Arab Americans. In the fully adjusted model, this association was slightly attenuated (OR=1.32; 95% CI=1.24, 1.41). These findings indicate English language ability is associated with variations in reporting a physical disability. Future studies should include better measures of acculturation. Arab Americans are heterogeneous and should be disaggregated both by subgroups and from the white category in order to reveal a more accurate health and disease status profile for these groups. These efforts will assist in tailoring more effective interventions in reducing or preventing disability among Arab Americans 65 years of age and older. Copyright 2008 S. Karger AG, Basel.

bb̅ud̅ four-quark systems in the Born-Oppenheimer approximation: prospects and challenges

NASA Astrophysics Data System (ADS)

Peters, Antje; Bicudo, Pedro; Wagner, Marc

2018-03-01

We summarize previous work on b̅b̅ud four-quark systems in the Born-Oppenheimer approximation and discuss first steps towards an extension to the theoretically more challenging bb̅ud̅ system. Strategies to identify a possibly existing bb̅ud̅ bound state are discussed and first numerical results are presented.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Finzel, Kati, E-mail: kati.finzel@liu.se

The local conditions for the Pauli potential that are necessary in order to yield self-consistent electron densities from orbital-free calculations are investigated for approximations that are expressed with the help of a local position variable. It is shown that those local conditions also apply when the Pauli potential is given in terms of the electron density. An explicit formula for the Ne atom is given, preserving the local conditions during the iterative procedure. The resulting orbital-free electron density exhibits proper shell structure behavior and is in close agreement with the Kohn-Sham electron density. This study demonstrates that it is possiblemore » to obtain self-consistent orbital-free electron densities with proper atomic shell structure from simple one-point approximations for the Pauli potential at local density level.« less

Investigation of Tropospheric Pollutants and Stratospheric Ozone Using Infrared Fourier Transform Spectrometers from the Ground, Space and Balloons

NASA Astrophysics Data System (ADS)

Griffin, Debora

This thesis focusses on transport and composition of boreal fire plumes, evolution of trace gases in the Arctic, multi-year comparisons of ground-based and satellite-borne instruments, and depletion of Arctic ozone. Two similar Fourier Transform Spectrometer (FTS) instruments were utilized: (1) the ground-based and balloon-borne Portable Atmospheric Research Interferometric Spectrometer for the InfraRed (PARIS-IR) and (2) the space-borne Atmospheric Chemistry Experiment (ACE) FTS. Additional datasets, from other satellite and ground-based instruments, as well as Chemical Transport Models (CTMs) complemented the analysis. Transport and composition of boreal fire plumes were analysed with PARIS-IR measurements taken in Halifax, Nova Scotia. This study analysed the retrievals of different FTSs and investigated transport and composition of a smoke plume utilizing various models. The CO retrievals of three different FTSs (PARIS-IR, DA8, and IASI) were consistent and detected a smoke plume between 19 and 21 July 2011. These measurements were similar to the concentrations computed by GEOS-Chem ( 3% for CO and 8% for C2H6). Multi-year comparisons (2006-2013) of ground-based and satellite-borne FTSs near Eureka, Nunavut were carried out utilizing measurements from PARIS-IR, the Bruker 125HR and ACEFTS. The mean and interannual differences between the datasets were investigated for eight species (ozone, HCl, HNO3, HF, CH4, N2O, CO, and C2H6) and good agreement between these instruments was found. Furthermore, the evolution of the eight gases was investigated and increasing ozone, HCl, HF, CH4 and C2H6 were found. Springtime Arctic ozone depletion was studied, where six different methods to estimate ozone depletion were evaluated using the ACE-FTS dataset. It was shown that CH4, N2O, HF, and CCl2F2 are suitable tracers to estimate the ozone loss. The loss estimates (mixing ratio and partial column) are consistent for all six methods. Finally, PARIS-IR was prepared for a balloon-borne measurement campaign and a new suntracker for these measurements was designed and tested. The balloon was launched in September 2015. The suntracker performed with a +/-0.04° accuracy. From the balloon-borne sunset spectra, an ozone profile was retrieved and is consistent with measurements from a nearby ozonesonde within approximately 10 %.

Justifying quasiparticle self-consistent schemes via gradient optimization in Baym-Kadanoff theory.

PubMed

Ismail-Beigi, Sohrab

2017-09-27

The question of which non-interacting Green's function 'best' describes an interacting many-body electronic system is both of fundamental interest as well as of practical importance in describing electronic properties of materials in a realistic manner. Here, we study this question within the framework of Baym-Kadanoff theory, an approach where one locates the stationary point of a total energy functional of the one-particle Green's function in order to find the total ground-state energy as well as all one-particle properties such as the density matrix, chemical potential, or the quasiparticle energy spectrum and quasiparticle wave functions. For the case of the Klein functional, our basic finding is that minimizing the length of the gradient of the total energy functional over non-interacting Green's functions yields a set of self-consistent equations for quasiparticles that is identical to those of the quasiparticle self-consistent GW (QSGW) (van Schilfgaarde et al 2006 Phys. Rev. Lett. 96 226402-4) approach, thereby providing an a priori justification for such an approach to electronic structure calculations. In fact, this result is general, applies to any self-energy operator, and is not restricted to any particular approximation, e.g., the GW approximation for the self-energy. The approach also shows that, when working in the basis of quasiparticle states, solving the diagonal part of the self-consistent Dyson equation is of primary importance while the off-diagonals are of secondary importance, a common observation in the electronic structure literature of self-energy calculations. Finally, numerical tests and analytical arguments show that when the Dyson equation produces multiple quasiparticle solutions corresponding to a single non-interacting state, minimizing the length of the gradient translates into choosing the solution with largest quasiparticle weight.

Posttraumatic stress in immigrants from Central America and Mexico.

PubMed

Cervantes, R C; Salgado de Snyder, V N; Padilla, A M

1989-06-01

International migration has been associated with increased levels of psychological disturbance, particularly among refugees who have fled from war or political unrest. This study examined self-reported symptoms of depression, anxiety, somatization, generalized distress, and posttraumatic stress disorder (PTSD) in a community sample of 258 immigrants from Central America and Mexico and 329 native-born Mexican Americans and Anglo Americans. Immigrants were found to have higher levels of generalized distress than native-born Americans. Fifty-two percent of Central American immigrants who migrated as a result of war or political unrest reported symptoms consistent with a diagnosis of PTSD, compared with 49 percent of Central Americans who migrated for other reasons and 25 percent of Mexican immigrants. The authors call for more research to document the psychosocial aspects of migration.

Country of birth, parental background and self-rated health among adolescents: a population-based study.

PubMed

Lindström, Martin; Modén, Birgit; Rosvall, Maria

2014-12-01

The aim of this study was to investigate differences according to country of birth and parental country of birth, in relation to poor self-rated health (SRH), in Swedish adolescents. The Scania public health survey among children and adolescents, conducted in 2012, is a cross-sectional study including most pupils in grade 9 (15 years old), including in 32 of 33 municipalities. The participation rate was 83% (9,791 of 11,735). We performed logistic regressions to investigate the association between the students' country of birth, parental country of birth and poor SRH. Boys born outside Europe had an odds ratio (OR) 2.1 (1.6-2.8) of poor SRH in the unadjusted model, which was reduced to 0.7 (0.4-1.3) in the multiple model, as compared to boys born in Sweden with both or one parent born in Sweden. Boys born in Europe had an OR 0.4 (0.2-0.9) of poor SRH, after multiple adjustments. Girls born in Sweden with both parents born abroad, and girls born outside of Europe had significantly lower ORs of poor SRH in the multiple model. In particular, adjustment for socio-demographic and psychosocial factors reduced the ORs of poor SRH among boys, but did so to a lesser extent among girls. Differences in socio-demographic and psychosocial factors explained the higher odds of poor SRH among boys born outside of Europe. Girls born in Sweden with both parents born abroad, and girls born outside Europe, had significantly lower ORs of poor SRH. Our results indicate that there are gender differences in the factors behind poor self-rated health, according to the country-related background of adolescents in Sweden. © 2014 the Nordic Societies of Public Health.

Perturbations of the seismic reflectivity of a fluid-saturated depth-dependent poroelastic medium.

PubMed

de Barros, Louis; Dietrich, Michel

2008-03-01

Analytical formulas are derived to compute the first-order effects produced by plane inhomogeneities on the point source seismic response of a fluid-filled stratified porous medium. The derivation is achieved by a perturbation analysis of the poroelastic wave equations in the plane-wave domain using the Born approximation. This approach yields the Frechet derivatives of the P-SV- and SH-wave responses in terms of the Green's functions of the unperturbed medium. The accuracy and stability of the derived operators are checked by comparing, in the time-distance domain, differential seismograms computed from these analytical expressions with complete solutions obtained by introducing discrete perturbations into the model properties. For vertical and horizontal point forces, it is found that the Frechet derivative approach is remarkably accurate for small and localized perturbations of the medium properties which are consistent with the Born approximation requirements. Furthermore, the first-order formulation appears to be stable at all source-receiver offsets. The porosity, consolidation parameter, solid density, and mineral shear modulus emerge as the most sensitive parameters in forward and inverse modeling problems. Finally, the amplitude-versus-angle response of a thin layer shows strong coupling effects between several model parameters.

Nouvelles bornes et estimations pour les milieux poreux à matrice rigide parfaitement plastique

NASA Astrophysics Data System (ADS)

Bilger, Nicolas; Auslender, François; Bornert, Michel; Masson, Renaud

We derive new rigorous bounds and self-consistent estimates for the effective yield surface of porous media with a rigid perfectly plastic matrix and a microstructure similar to Hashin's composite spheres assemblage. These results arise from a homogenisation technique that combines a pattern-based modelling for linear composite materials and a variational formulation for nonlinear media. To cite this article: N. Bilger et al., C. R. Mecanique 330 (2002) 127-132.

Stigma, discrimination, or symptomatology differences in self-reported mental health between US-born and Somalia-born Black Americans.

PubMed

Henning-Smith, Carrie; Shippee, Tetyana P; McAlpine, Donna; Hardeman, Rachel; Farah, Farhiya

2013-05-01

We examined differences in self-reported mental health (SRMH) between US-born and Somalia-born Black Americans compared with White Americans. We tested how SRMH was affected by stigma toward seeing a mental health provider, discrimination in the health care setting, or symptoms of depression. Data were from a 2008 survey of adults in Minnesota and were limited to US-born and Somalia-born Black and White Americans (n = 938). Somalia-born adults were more likely to report better SRMH than either US-born Black or White Americans. They also reported lower levels of discrimination (18.6%) than US-born Black Americans (33.4%), higher levels of stigma (23.6% vs 4.7%), and lower levels of depressive symptoms (9.1% vs 31.6%). Controlling for stigma, discrimination, and symptomatology, Somalia-born Black Americans reported better SRMH than White and Black Americans (odds ratio = 4.76). Mental health programming and health care providers who focus on Black Americans' mental health might be missing important sources of heterogeneity. It is essential to consider the role of race and ethnicity, but also of nativity, in mental health policy and programming.

Stigma, Discrimination, or Symptomatology Differences in Self-Reported Mental Health Between US-Born and Somalia-Born Black Americans

PubMed Central

Shippee, Tetyana P.; McAlpine, Donna; Hardeman, Rachel; Farah, Farhiya

2013-01-01

Objectives. We examined differences in self-reported mental health (SRMH) between US-born and Somalia-born Black Americans compared with White Americans. We tested how SRMH was affected by stigma toward seeing a mental health provider, discrimination in the health care setting, or symptoms of depression. Methods. Data were from a 2008 survey of adults in Minnesota and were limited to US-born and Somalia-born Black and White Americans (n = 938). Results. Somalia-born adults were more likely to report better SRMH than either US-born Black or White Americans. They also reported lower levels of discrimination (18.6%) than US-born Black Americans (33.4%), higher levels of stigma (23.6% vs 4.7%), and lower levels of depressive symptoms (9.1% vs 31.6%). Controlling for stigma, discrimination, and symptomatology, Somalia-born Black Americans reported better SRMH than White and Black Americans (odds ratio = 4.76). Conclusions. Mental health programming and health care providers who focus on Black Americans’ mental health might be missing important sources of heterogeneity. It is essential to consider the role of race and ethnicity, but also of nativity, in mental health policy and programming. PMID:23488506

Optimized Hypernetted-Chain Solutions for Helium -4 Surfaces and Metal Surfaces

NASA Astrophysics Data System (ADS)

Qian, Guo-Xin

This thesis is a study of inhomogeneous Bose systems such as liquid ('4)He slabs and inhomogeneous Fermi systems such as the electron gas in metal films, at zero temperature. Using a Jastrow-type many-body wavefunction, the ground state energy is expressed by means of Bogoliubov-Born-Green-Kirkwood -Yvon and Hypernetted-Chain techniques. For Bose systems, Euler-Lagrange equations are derived for the one- and two -body functions and systematic approximation methods are physically motivated. It is shown that the optimized variational method includes a self-consistent summation of ladder- and ring-diagrams of conventional many-body theory. For Fermi systems, a linear potential model is adopted to generate the optimized Hartree-Fock basis. Euler-Lagrange equations are derived for the two-body correlations which serve to screen the strong bare Coulomb interaction. The optimization of the pair correlation leads to an expression of correlation energy in which the state averaged RPA part is separated. Numerical applications are presented for the density profile and pair distribution function for both ('4)He surfaces and metal surfaces. Both the bulk and surface energies are calculated in good agreement with experiments.

Low-temperature thermal transport and thermopower of monolayer transition metal dichalcogenide semiconductors

NASA Astrophysics Data System (ADS)

Sengupta, Parijat; Tan, Yaohua; Klimeck, Gerhard; Shi, Junxia

2017-10-01

We study the low temperature thermal conductivity of single-layer transition metal dichalcogenides (TMDCs). In the low temperature regime where heat is carried primarily through transport of electrons, thermal conductivity is linked to electrical conductivity through the Wiedemann-Franz law (WFL). Using a k.p Hamiltonian that describes the K and K{\\prime} valley edges, we compute the zero-frequency electric (Drude) conductivity using the Kubo formula to obtain a numerical estimate for the thermal conductivity. The impurity scattering determined transit time of electrons which enters the Drude expression is evaluated within the self-consistent Born approximation. The analytic expressions derived show that low temperature thermal conductivity (1) is determined by the band gap at the valley edges in monolayer TMDCs and (2) in presence of disorder which can give rise to the variable range hopping regime, there is a distinct reduction. Additionally, we compute the Mott thermopower and demonstrate that under a high frequency light beam, a valley-resolved thermopower can be obtained. A closing summary reviews the implications of results followed by a brief discussion on applicability of the WFL and its breakdown in context of the presented calculations.

Ethnic differences in self reported health in Malmö in southern Sweden

PubMed Central

Lindstrom, M; Sundquist, J; Ostergren, P

2001-01-01

STUDY OBJECTIVE—The aim of this study was to investigate ethnic differences in self reported health in the city of Malmö, Sweden, and whether these differences could be explained by psychosocial and economic conditions.
DESIGN/SETTING/PARTICIPANTS—The public health survey in Malmö 1994 was a cross sectional study. A total of 5600 people aged 20-80 years completed a postal questionnaire. The participation rate was 71%. The population was categorised according to country of origin: born in Sweden, other Western countries, Yugoslavia, Poland, Arabic speaking countries and all other countries. The multivariate analysis was performed using a logistic regression model in order to investigate the importance of possible confounders on the differences by country of origin in self reported health. Finally, variables measuring psychosocial and economic conditions were introduced into the model.
MAIN RESULTS—The odds ratios of having poor self reported health were significantly higher among men born in other Western countries, Yugoslavia, Arabic speaking countries and in the category all other countries, as well as among women born in Yugoslavia, Poland and all other countries, compared with men and women born in Sweden. The multivariate analysis including age and education did not change these results. A huge reduction of the odds ratios was observed for men and women born in Yugoslavia, Arabic speaking countries and all other countries, and for women born in Poland after the introduction of the social network, social support and economic factors into the multivariate model.
CONCLUSIONS—There were significant ethnic group differences in self reported health. These differences were greatly reduced by psychosocial and economic factors, which suggest that these factors may be important determinants of self rated health in certain minority groups.


Keywords: self reported health; social network; social support PMID:11154248

Convergence of the strong-potential-Born approximation in Z/sub less-than//Z/sub greater-than/

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGuire, J.H.; Sil, N.C.

1986-01-01

Convergence of the strong-potential Born (SPB) approximation as a function of the charges of the projectile and target is studied numerically. Time-reversal invariance (or detailed balance) is satisfied at sufficiently high velocities even when the charges are asymmetric. This demonstarates that the SPB approximation converges to the correct result even when the charge of the ''weak'' potential, which is kept to first order, is larger than the charge of the ''strong'' potential, which is retained to all orders. Consequently, the SPB approximation is valid for systems of arbitrary charge symmetry (including symmetric systems) at sufficiently high velocities.

Performance of extended Lagrangian schemes for molecular dynamics simulations with classical polarizable force fields and density functional theory

NASA Astrophysics Data System (ADS)

Vitale, Valerio; Dziedzic, Jacek; Albaugh, Alex; Niklasson, Anders M. N.; Head-Gordon, Teresa; Skylaris, Chris-Kriton

2017-03-01

Iterative energy minimization with the aim of achieving self-consistency is a common feature of Born-Oppenheimer molecular dynamics (BOMD) and classical molecular dynamics with polarizable force fields. In the former, the electronic degrees of freedom are optimized, while the latter often involves an iterative determination of induced point dipoles. The computational effort of the self-consistency procedure can be reduced by re-using converged solutions from previous time steps. However, this must be done carefully, as not to break time-reversal symmetry, which negatively impacts energy conservation. Self-consistent schemes based on the extended Lagrangian formalism, where the initial guesses for the optimized quantities are treated as auxiliary degrees of freedom, constitute one elegant solution. We report on the performance of two integration schemes with the same underlying extended Lagrangian structure, which we both employ in two radically distinct regimes—in classical molecular dynamics simulations with the AMOEBA polarizable force field and in BOMD simulations with the Onetep linear-scaling density functional theory (LS-DFT) approach. Both integration schemes are found to offer significant improvements over the standard (unpropagated) molecular dynamics formulation in both the classical and LS-DFT regimes.

Performance of extended Lagrangian schemes for molecular dynamics simulations with classical polarizable force fields and density functional theory.

PubMed

Vitale, Valerio; Dziedzic, Jacek; Albaugh, Alex; Niklasson, Anders M N; Head-Gordon, Teresa; Skylaris, Chris-Kriton

2017-03-28

Iterative energy minimization with the aim of achieving self-consistency is a common feature of Born-Oppenheimer molecular dynamics (BOMD) and classical molecular dynamics with polarizable force fields. In the former, the electronic degrees of freedom are optimized, while the latter often involves an iterative determination of induced point dipoles. The computational effort of the self-consistency procedure can be reduced by re-using converged solutions from previous time steps. However, this must be done carefully, as not to break time-reversal symmetry, which negatively impacts energy conservation. Self-consistent schemes based on the extended Lagrangian formalism, where the initial guesses for the optimized quantities are treated as auxiliary degrees of freedom, constitute one elegant solution. We report on the performance of two integration schemes with the same underlying extended Lagrangian structure, which we both employ in two radically distinct regimes-in classical molecular dynamics simulations with the AMOEBA polarizable force field and in BOMD simulations with the Onetep linear-scaling density functional theory (LS-DFT) approach. Both integration schemes are found to offer significant improvements over the standard (unpropagated) molecular dynamics formulation in both the classical and LS-DFT regimes.

Performance of extended Lagrangian schemes for molecular dynamics simulations with classical polarizable force fields and density functional theory

DOE PAGES

Vitale, Valerio; Dziedzic, Jacek; Albaugh, Alex; ...

2017-03-28

Iterative energy minimization with the aim of achieving self-consistency is a common feature of Born-Oppenheimer molecular dynamics (BOMD) and classical molecular dynamics with polarizable force fields. In the former, the electronic degrees of freedom are optimized, while the latter often involves an iterative determination of induced point dipoles. The computational effort of the self-consistency procedure can be reduced by re-using converged solutions from previous time steps. However, this must be done carefully, as not to break time-reversal symmetry, which negatively impacts energy conservation. Self-consistent schemes based on the extended Lagrangian formalism, where the initial guesses for the optimized quantities aremore » treated as auxiliary degrees of freedom, constitute one elegant solution. We report on the performance of two integration schemes with the same underlying extended Lagrangian structure, which we both employ in two radically distinct regimes—in classical molecular dynamics simulations with the AMOEBA polarizable force field and in BOMD simulations with the Onetep linear-scaling density functional theory (LS-DFT) approach. Furthermore, both integration schemes are found to offer significant improvements over the standard (unpropagated) molecular dynamics formulation in both the classical and LS-DFT regimes.« less

Performance of extended Lagrangian schemes for molecular dynamics simulations with classical polarizable force fields and density functional theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vitale, Valerio; Dziedzic, Jacek; Albaugh, Alex

Iterative energy minimization with the aim of achieving self-consistency is a common feature of Born-Oppenheimer molecular dynamics (BOMD) and classical molecular dynamics with polarizable force fields. In the former, the electronic degrees of freedom are optimized, while the latter often involves an iterative determination of induced point dipoles. The computational effort of the self-consistency procedure can be reduced by re-using converged solutions from previous time steps. However, this must be done carefully, as not to break time-reversal symmetry, which negatively impacts energy conservation. Self-consistent schemes based on the extended Lagrangian formalism, where the initial guesses for the optimized quantities aremore » treated as auxiliary degrees of freedom, constitute one elegant solution. We report on the performance of two integration schemes with the same underlying extended Lagrangian structure, which we both employ in two radically distinct regimes—in classical molecular dynamics simulations with the AMOEBA polarizable force field and in BOMD simulations with the Onetep linear-scaling density functional theory (LS-DFT) approach. Furthermore, both integration schemes are found to offer significant improvements over the standard (unpropagated) molecular dynamics formulation in both the classical and LS-DFT regimes.« less

Branch-Based Model for the Diameters of the Pulmonary Airways: Accounting for Departures From Self-Consistency and Registration Errors

PubMed Central

Neradilek, Moni B.; Polissar, Nayak L.; Einstein, Daniel R.; Glenny, Robb W.; Minard, Kevin R.; Carson, James P.; Jiao, Xiangmin; Jacob, Richard E.; Cox, Timothy C.; Postlethwait, Edward M.; Corley, Richard A.

2017-01-01

We examine a previously published branch-based approach for modeling airway diameters that is predicated on the assumption of self-consistency across all levels of the tree. We mathematically formulate this assumption, propose a method to test it and develop a more general model to be used when the assumption is violated. We discuss the effect of measurement error on the estimated models and propose methods that take account of error. The methods are illustrated on data from MRI and CT images of silicone casts of two rats, two normal monkeys, and one ozone-exposed monkey. Our results showed substantial departures from self-consistency in all five subjects. When departures from self-consistency exist, we do not recommend using the self-consistency model, even as an approximation, as we have shown that it may likely lead to an incorrect representation of the diameter geometry. The new variance model can be used instead. Measurement error has an important impact on the estimated morphometry models and needs to be addressed in the analysis. PMID:22528468

Microwave beam broadening due to turbulent plasma density fluctuations within the limit of the Born approximation and beyond

NASA Astrophysics Data System (ADS)

Köhn, A.; Guidi, L.; Holzhauer, E.; Maj, O.; Poli, E.; Snicker, A.; Weber, H.

2018-07-01

Plasma turbulence, and edge density fluctuations in particular, can under certain conditions broaden the cross-section of injected microwave beams significantly. This can be a severe problem for applications relying on well-localized deposition of the microwave power, like the control of MHD instabilities. Here we investigate this broadening mechanism as a function of fluctuation level, background density and propagation length in a fusion-relevant scenario using two numerical codes, the full-wave code IPF-FDMC and the novel wave kinetic equation solver WKBeam. The latter treats the effects of fluctuations using a statistical approach, based on an iterative solution of the scattering problem (Born approximation). The full-wave simulations are used to benchmark this approach. The Born approximation is shown to be valid over a large parameter range, including ITER-relevant scenarios.

Nonequilibrium self-energy functional theory

NASA Astrophysics Data System (ADS)

Hofmann, Felix; Eckstein, Martin; Arrigoni, Enrico; Potthoff, Michael

2013-10-01

The self-energy functional theory (SFT) is generalized to describe the real-time dynamics of correlated lattice-fermion models far from thermal equilibrium. This is achieved by starting from a reformulation of the original equilibrium theory in terms of double-time Green's functions on the Keldysh-Matsubara contour. With the help of a generalized Luttinger-Ward functional, we construct a functional Ω̂[Σ] which is stationary at the physical (nonequilibrium) self-energy Σ and which yields the grand potential of the initial thermal state Ω at the physical point. Nonperturbative approximations can be defined by specifying a reference system that serves to generate trial self-energies. These self-energies are varied by varying the reference system's one-particle parameters on the Keldysh-Matsubara contour. In the case of thermal equilibrium, this approach reduces to the conventional SFT. Contrary to the equilibrium theory, however, “unphysical” variations, i.e., variations that are different on the upper and the lower branches of the Keldysh contour, must be considered to fix the time dependence of the optimal physical parameters via the variational principle. Functional derivatives in the nonequilibrium SFT Euler equation are carried out analytically to derive conditional equations for the variational parameters that are accessible to a numerical evaluation via a time-propagation scheme. Approximations constructed by means of the nonequilibrium SFT are shown to be inherently causal, internally consistent, and to respect macroscopic conservation laws resulting from gauge symmetries of the Hamiltonian. This comprises the nonequilibrium dynamical mean-field theory but also dynamical-impurity and variational-cluster approximations that are specified by reference systems with a finite number of degrees of freedom. In this way, nonperturbative and consistent approximations can be set up, the numerical evaluation of which is accessible to an exact-diagonalization approach.

Influence of scattering processes on electron quantum states in nanowires

PubMed Central

Galenchik, Vadim; Borzdov, Andrei; Borzdov, Vladimir; Komarov, Fadei

2007-01-01

In the framework of quantum perturbation theory the self-consistent method of calculation of electron scattering rates in nanowires with the one-dimensional electron gas in the quantum limit is worked out. The developed method allows both the collisional broadening and the quantum correlations between scattering events to be taken into account. It is an alternativeper seto the Fock approximation for the self-energy approach based on Green’s function formalism. However this approach is free of mathematical difficulties typical to the Fock approximation. Moreover, the developed method is simpler than the Fock approximation from the computational point of view. Using the approximation of stable one-particle quantum states it is proved that the electron scattering processes determine the dependence of electron energy versus its wave vector.

Prevalence of Hepatitis B Surface Antigen in US-Born and Foreign-Born Asian/Pacific Islander College Students

ERIC Educational Resources Information Center

Quang, Yen N.; Vu, Joanne; Yuk, Jihey; Li, Chin-Shang; Chen, Moon; Bowlus, Christopher L.

2010-01-01

The prevalence of chronic hepatitis B (HBV) among college-age US-born Asian and Pacific Islanders (A/PI) is not well known. Objectives: To compare the prevalence of hepatitis B surface antigen (HBsAg) seropositivity in US-born to A/PI-born students at a public university. Participants: Undergraduate who self-identified themselves as A/PI. Results:…

Where are you from? A validation of the Foreigner Objectification Scale and the psychological correlates of foreigner objectification among Asian Americans and Latinos.

PubMed

Armenta, Brian E; Lee, Richard M; Pituc, Stephanie T; Jung, Kyoung-Rae; Park, Irene J K; Soto, José A; Kim, Su Yeong; Schwartz, Seth J

2013-04-01

Many ethnic minorities in the United States consider themselves to be just as American as their European American counterparts. However, there is a persistent cultural stereotype of ethnic minorities as foreigners (i.e., the perpetual foreigner stereotype) that may be expressed during interpersonal interactions (i.e., foreigner objectification). The goal of the present study was to validate the Foreigner Objectification Scale, a brief self-report measure of perceived foreigner objectification, and to examine the psychological correlates of perceived foreigner objectification. Results indicated that the Foreigner Objectification Scale is structurally (i.e., factor structure) and metrically (i.e., factor loadings) invariant across foreign-born and U.S.-born Asian Americans and Latinos. Scalar (i.e., latent item intercepts) invariance was demonstrated for the two foreign-born groups and the two U.S.-born groups, but not across foreign-born and U.S.-born individuals. Multiple-group structural equation models indicated that, among U.S.-born individuals, perceived foreigner objectification was associated with less life satisfaction and more depressive symptoms, and was indirectly associated with lower self-esteem via identity denial, operationalized as the perception that one is not viewed by others as American. Among foreign-born individuals, perceived foreigner objectification was not significantly associated directly with self-esteem, life satisfaction, or depressive symptoms. However, perceived foreigner objectification was positively associated with identity denial, and identity denial was negatively associated with life satisfaction. This study illustrates the relevance of perceived foreigner objectification to the psychological well-being of U.S.-born Asian Americans and Latinos.

Adult psychological functioning of individuals born with craniofacial anomalies.

PubMed

Sarwer, D B; Bartlett, S P; Whitaker, L A; Paige, K T; Pertschuk, M J; Wadden, T A

1999-02-01

This study represents an initial investigation into the adult psychological functioning of individuals born with craniofacial disfigurement. A total of 24 men and women born with a craniofacial anomaly completed paper and pencil measures of body image dissatisfaction, self-esteem, quality of life, and experiences of discrimination. An age- and gender-matched control group of 24 non-facially disfigured adults also completed the measures. As expected, craniofacially disfigured adults reported greater dissatisfaction with their facial appearance than did the control group. Craniofacially disfigured adults also reported significantly lower levels of self-esteem and quality of life. Dissatisfaction with facial appearance, self-esteem, and quality of life were related to self-ratings of physical attractiveness. More than one-third of craniofacially disfigured adults (38 percent) reported experiences of discrimination in employment or social settings. Among disfigured adults, psychological functioning was not related to number of surgeries, although the degree of residual facial deformity was related to increased dissatisfaction with facial appearance and greater experiences of discrimination. Results suggest that adults who were born with craniofacial disfigurement, as compared with non-facially disfigured adults, experience greater dissatisfaction with facial appearance and lower self-esteem and quality of life; however, these experiences do not seem to be universal.

Testing strong-segregation theory against self-consistent-field theory for block copolymer melts

NASA Astrophysics Data System (ADS)

Matsen, M. W.

2001-06-01

We introduce a highly efficient self-consistent-field theory (SCFT) method for examining the cylindrical and spherical block copolymer morphologies using a standard unit cell approximation (UCA). The method is used to calculate the classical diblock copolymer phase boundaries deep into the strong-segregation regime, where they can be compared with recent improvements to strong-segregation theory (SST). The comparison suggests a significant discrepancy between the two theories indicating that our understanding of strongly stretched polymer brushes is still incomplete.

Self-consistent models for Coulomb-heated X-ray pulsar atmospheres

NASA Technical Reports Server (NTRS)

Harding, A. K.; Kirk, J. G.; Galloway, D. J.; Meszaros, P.

1984-01-01

Calculations of accreting magnetized neutron star atmospheres heated by the gradual deceleration of Protons via Coulomb collisions are presented. Self consistent determinations of the temperature and density structure for different accretion rates are made by assuming hydrostatic equilibrium and energy balance, coupled with radiative transfer. The full radiative transfer in two polarizations, using magnetic cross sections but with cyclotron resonance effects treated approximately, is carried out in the inhomogeneous atmospheres. Previously announced in STAR as N84-12012

Self-consistent mean-field approach to the statistical level density in spherical nuclei

NASA Astrophysics Data System (ADS)

Kolomietz, V. M.; Sanzhur, A. I.; Shlomo, S.

2018-06-01

A self-consistent mean-field approach within the extended Thomas-Fermi approximation with Skyrme forces is applied to the calculations of the statistical level density in spherical nuclei. Landau's concept of quasiparticles with the nucleon effective mass and the correct description of the continuum states for the finite-depth potentials are taken into consideration. The A dependence and the temperature dependence of the statistical inverse level-density parameter K is obtained in a good agreement with experimental data.

Towards a unification of the hierarchical reference theory and the self-consistent Ornstein-Zernike approximation.

PubMed

Reiner, A; Høye, J S

2005-12-01

The hierarchical reference theory and the self-consistent Ornstein-Zernike approximation are two liquid state theories that both furnish a largely satisfactory description of the critical region as well as phase coexistence and the equation of state in general. Furthermore, there are a number of similarities that suggest the possibility of a unification of both theories. As a first step towards this goal, we consider the problem of combining the lowest order gamma expansion result for the incorporation of a Fourier component of the interaction with the requirement of consistency between internal and free energies, leaving aside the compressibility relation. For simplicity, we restrict ourselves to a simplified lattice gas that is expected to display the same qualitative behavior as more elaborate models. It turns out that the analytically tractable mean spherical approximation is a solution to this problem, as are several of its generalizations. Analysis of the characteristic equations shows the potential for a practical scheme and yields necessary conditions that any closure to the Ornstein-Zernike relation must fulfill for the consistency problem to be well posed and to have a unique differentiable solution. These criteria are expected to remain valid for more general discrete and continuous systems, even if consistency with the compressibility route is also enforced where possible explicit solutions will require numerical evaluations.

A new probability distribution model of turbulent irradiance based on Born perturbation theory

NASA Astrophysics Data System (ADS)

Wang, Hongxing; Liu, Min; Hu, Hao; Wang, Qian; Liu, Xiguo

2010-10-01

The subject of the PDF (Probability Density Function) of the irradiance fluctuations in a turbulent atmosphere is still unsettled. Theory reliably describes the behavior in the weak turbulence regime, but theoretical description in the strong and whole turbulence regimes are still controversial. Based on Born perturbation theory, the physical manifestations and correlations of three typical PDF models (Rice-Nakagami, exponential-Bessel and negative-exponential distribution) were theoretically analyzed. It is shown that these models can be derived by separately making circular-Gaussian, strong-turbulence and strong-turbulence-circular-Gaussian approximations in Born perturbation theory, which denies the viewpoint that the Rice-Nakagami model is only applicable in the extremely weak turbulence regime and provides theoretical arguments for choosing rational models in practical applications. In addition, a common shortcoming of the three models is that they are all approximations. A new model, called the Maclaurin-spread distribution, is proposed without any approximation except for assuming the correlation coefficient to be zero. So, it is considered that the new model can exactly reflect the Born perturbation theory. Simulated results prove the accuracy of this new model.

Testing variations of the GW approximation on strongly correlated transition metal oxides: hematite (α-Fe2O3) as a benchmark.

PubMed

Liao, Peilin; Carter, Emily A

2011-09-07

Quantitative characterization of low-lying excited electronic states in materials is critical for the development of solar energy conversion materials. The many-body Green's function method known as the GW approximation (GWA) directly probes states corresponding to photoemission and inverse photoemission experiments, thereby determining the associated band structure. Several versions of the GW approximation with different levels of self-consistency exist in the field. While the GWA based on density functional theory (DFT) works well for conventional semiconductors, less is known about its reliability for strongly correlated semiconducting materials. Here we present a systematic study of the GWA using hematite (α-Fe(2)O(3)) as the benchmark material. We analyze its performance in terms of the calculated photoemission/inverse photoemission band gaps, densities of states, and dielectric functions. Overall, a non-self-consistent G(0)W(0) using input from DFT+U theory produces physical observables in best agreement with experiments. This journal is © the Owner Societies 2011

Nativity and nutritional behaviors in the Mexican origin population living in the US-Mexico border region.

PubMed

Montoya, Jared A; Salinas, Jennifer J; Barroso, Cristina S; Mitchell-Bennett, Lisa; Reininger, Belinda

2011-02-01

The purpose of this study is to determine the relationship between nativity and nutritional behaviors and beliefs in the Mexican American population living in the South Texas border region. Mexican Americans living the border region of South Texas were sampled to assess their nutrition behaviors and beliefs. Nativity was measured as whether subjects were born in the United States or Mexico. Nutritional behaviors were measured using the SPAN and indexes were used to measure barriers to good nutrition, dietary self-efficacy, and dietary importance. OLS regression analysis was used and adjustments were made for sociodemographic factors. Differences between US-born Mexican Americans and Mexico-born Mexican Americans existed in nutritional beliefs, but not in behaviors. Mexico-born Mexican Americans reported their dietary choices as more important and reported greater food self-efficacy than their US-born Mexican American counterparts. Socioeconomic status influenced US-born Mexican Americans nutritional beliefs only and the same effect was not observed for Mexico-born Mexican Americans. Despite low levels of overall acculturation in the border region dietary beliefs still exist between immigrants and US-born Mexican Americans in dietary beliefs, but, not behaviors in US-born Mexican Americans.

Molecular subtyping of Clostridium perfringens by pulsed-field gel electrophoresis to facilitate food-borne-disease outbreak investigations.

PubMed

Maslanka, S E; Kerr, J G; Williams, G; Barbaree, J M; Carson, L A; Miller, J M; Swaminathan, B

1999-07-01

Clostridium perfringens is a common cause of food-borne illness. The illness is characterized by profuse diarrhea and acute abdominal pain. Since the illness is usually self-limiting, many cases are undiagnosed and/or not reported. Investigations are often pursued after an outbreak involving large numbers of people in institutions, at restaurants, or at catered meals. Serotyping has been used in the past to assist epidemiologic investigations of C. perfringens outbreaks. However, serotyping reagents are not widely available, and many isolates are often untypeable with existing reagents. We developed a pulsed-field gel electrophoresis (PFGE) method for molecular subtyping of C. perfringens isolates to aid in epidemiologic investigations of food-borne outbreaks. Six restriction endonucleases (SmaI, ApaI, FspI, MluI, KspI, and XbaI) were evaluated with a select panel of C. perfringens strains. SmaI was chosen for further studies because it produced 11 to 13 well-distributed bands of 40 to approximately 1,100 kb which provided good discrimination between isolates. Seventeen distinct patterns were obtained with 62 isolates from seven outbreak investigations or control strains. In general, multiple isolates from a single individual had indistinguishable PFGE patterns. Epidemiologically unrelated isolates (outbreak or control strains) had unique patterns; isolates from different individuals within an outbreak had similar, if not identical, patterns. PFGE identifies clonal relationships of isolates which will assist epidemiologic investigations of food-borne-disease outbreaks caused by C. perfringens.

The closure approximation in the hierarchy equations.

NASA Technical Reports Server (NTRS)

Adomian, G.

1971-01-01

The expectation of the solution process in a stochastic operator equation can be obtained from averaged equations only under very special circumstances. Conditions for validity are given and the significance and validity of the approximation in widely used hierarchy methods and the ?self-consistent field' approximation in nonequilibrium statistical mechanics are clarified. The error at any level of the hierarchy can be given and can be avoided by the use of the iterative method.

Racial Discrimination, Psychological Distress, and Self-Rated Health Among US-Born and Foreign-Born Black Americans

PubMed Central

Kosheleva, Anna; Waterman, Pamela D.; Chen, Jarvis T.; Koenen, Karestan

2011-01-01

Objectives. We investigated associations among racial discrimination, psychological distress, and self-rated health among US-born and immigrant Black Americans. Methods. We conducted a cross-sectional analysis of a cohort of employed working-class Black Americans (193 US-born, 275 foreign-born). Results. Both US-born and foreign-born Black participants had high levels of exposure to poverty (51% and 57%, respectively) and racial discrimination (76% and 60%) and reported high levels of severe psychological distress (14% and 16% had a Kessler 6 [K6] score of 13 or greater); 17% and 7% reported fair or poor health. After controlling for relevant covariates, their risk parameters for racial discrimination (high vs no exposure) were 4.0 (95% confidence interval [CI] = 2.3, 5.6) and 3.3 (95% CI = 2.1, 4.5), respectively, for continuous K6 score; corresponding odds ratios for severe psychological distress were 6.9 (95% CI = 1.4, 35.7) and 6.8 (95% CI = 2.5, 18.3). No associations existed between racial discrimination and self-reported health, suggesting that an underlying propensity to report adversity does not account for our psychological distress findings. Conclusions. Our results attest to the salience of racial discrimination, nativity, and socioeconomic position in understanding the experiences and psychological health of Black Americans. PMID:21778504

Ethnicity, Nativity and the Health of American Blacks

PubMed Central

Griffith, Derek M.; Johnson, Jonetta; Zhang, Rong; Neighbors, Harold W.; Jackson, James S.

2012-01-01

Few national studies have empirically examined ethnic differences in health within the American Black population. We utilized logistic regression to examine the relationships among ethnicity, nativity, depressive symptoms, and physical health in the two largest ethnic groups of American Blacks, African Americans and Caribbean Blacks. The data were from the National Survey of American Life, an in-person national household survey representative of the non-institutionalized U.S. Black population. We found that African Americans, U.S.-born Caribbean Blacks, and Caribbean-born Blacks had significantly different self-ratings of their health and self-reports of being diagnosed with a chronic physical health condition. Whether assessed by self-rated health or the presence of at least one physician diagnosed chronic health condition, Caribbean-born Blacks had the best health outcomes and U.S.-born Caribbean Blacks had the worst. This finding remained significant even after considering self-reported depressive symptoms. This study highlights the importance of considering ethnic diversity, nativity and immigration as independent sources of variation in health status within the American Black population. PMID:21317512

Microencapsulation of Self Healing Agents for Corrosion Control Coatings

NASA Technical Reports Server (NTRS)

Jolley, S. T.; Li, W.; Buhrow, J. W.; Calle, L. M.

2011-01-01

Corrosion, the environmentally induced degradation of materials, is a very costly problem that has a major impact on the global economy. Results from a 2-year breakthrough study released in 2002 by the U.S. Federal Highway Administration (FHWA) showed that the total annual estimated direct cost associated with metallic corrosion in nearly every U.S. industry sector was a staggering $276 billion, approximately 3.1% of the nation's Gross Domestic Product (GOP). Corrosion protective coatings are widely used to protect metallic structures from the detrimental effects of corrosion but their effectiveness can be seriously compromised by mechanical damage, such as a scratch, that exposes the metallic substrate. The incorporation of a self healing mechanism into a corrosion control coating would have the potential to significantly increase its effectiveness and useful lifetime. This paper describes work performed to incorporate a number of microcapsule-based self healing systems into corrosion control coatings. The work includes the preparation and evaluation of self-healing systems based on curable epoxy, acrylate, and siloxane resins, as well as, microencapsulated systems based on passive, solvent born, healing agent delivery. The synthesis and optimization of microcapsule-based self healing systems for thin coating (less than 100 micron) will be presented.

A numerical analysis of the Born approximation for image formation modeling of differential interference contrast microscopy for human embryos

NASA Astrophysics Data System (ADS)

Trattner, Sigal; Feigin, Micha; Greenspan, Hayit; Sochen, Nir

2008-03-01

The differential interference contrast (DIC) microscope is commonly used for the visualization of live biological specimens. It enables the view of the transparent specimens while preserving their viability, being a non-invasive modality. Fertility clinics often use the DIC microscope for evaluation of human embryos quality. Towards quantification and reconstruction of the visualized specimens, an image formation model for DIC imaging is sought and the interaction of light waves with biological matter is examined. In many image formation models the light-matter interaction is expressed via the first Born approximation. The validity region of this approximation is defined in a theoretical bound which limits its use to very small specimens with low dielectric contrast. In this work the Born approximation is investigated via the Helmholtz equation, which describes the interaction between the specimen and light. A solution on the lens field is derived using the Gaussian Legendre quadrature formulation. This numerical scheme is considered both accurate and efficient and has shortened significantly the computation time as compared to integration methods that required a great amount of sampling for satisfying the Whittaker - Shannon sampling theorem. By comparing the numerical results with the theoretical values it is shown that the theoretical bound is not directly relevant to microscopic imaging and is far too limiting. The numerical exhaustive experiments show that the Born approximation is inappropriate for modeling the visualization of thick human embryos.

/sub 1//sup 1/H/sup +/- and /sub 2//sup 4/He/sup +/-induced M-shell x-ray-production cross sections for selected elements in the rare-earth region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mehta, R.; Duggan, J.L.; Price, J.L.

1983-12-01

The measurements of M-shell x-ray-production cross sections induced by /sub 1//sup 1/H/sup +/ and /sub 2//sup 4/He/sup +/ ions are compared to the first-Born-approximation and ECPSSR (energy loss, Coulomb-deflection effects; perturbed-stationary-state approximation, with relativistic corrections) theories. Most of the reported experimental data were measured in our laboratory and the other measurements were taken from the literature. The data from our laboratory were for incident H/sup +/ and He/sup +/ ions in the energy range from 0.25 to 2.5 MeV. The M-shell x-ray-production cross sections were measured for the following thin targets: /sub 59/Pr, /sub 60/Nd, /sub 63/Eu, /sub 64/Gd, /submore » 66/Dy, /sub 67/Ho, /sub 68/Er, /sub 70/Yb, and /sub 72/Hf. The data from the literature were for protons and He/sup +/ ions in the energy range from 30 keV to 40 MeV. These data were for the following elements: /sub 54/Xe, /sub 59/Pr, /sub 60/Nd, /sub 62/Sm, /sub 63/Eu, /sub 64/Gd, /sub 65/Tb, /sub 66/Dy, /sub 67/Ho, /sub 68/Er, /sub 70/Yb, /sub 72/Hf, /sub 73/Ta, /sub 74/W, /sub 78/Pt, /sub 79/Au, /sub 80/Hg, /sub 82/Pb, /sub 83/Bi, and /sub 92/U. The first-Born-approximation calculations of the ionization cross section were made using the plane-wave Born approximation for direct ionization and the Oppenheimer-Brinkman-Kramers approximation of Nikolaev for electron capture. The ECPSSR theory of Brandt and Lapicki (Phys. Rev. A 23, 1717 (1981)) goes beyond the first Born approximation and accounts for the energy loss, Coulomb deflection, and relativistic effects in the perturbed-stationary-state theory. The first Born approximation overpredicts all measurements. The ECPSSR theory predicts the M-shell production cross sections correctly for Z/sub 2/>70 and energies per ..mu..>0.25 MeV/..mu...« less

Association of birthplace and self-reported hypertension by racial/ethnic groups among US adults--National Health Interview Survey, 2006-2010.

PubMed

Fang, Jing; Ayala, Carma; Loustalot, Fleetwood

2012-12-01

Over the past few decades, the proportion of US adults who were foreign-born has been increasing, as has the overall prevalence of hypertension. Here, we compared the prevalence of self-reported hypertension among native-born adults with that among foreign-born adults, classified by racial/ethnic group. Using 2006-2010 data from the National Health Interview Survey (NHIS), we compared the age-adjusted prevalence of hypertension among native-born adults to foreign-born adults, specified by continent of birthplace and race/ethnicity. Results are expressed as unadjusted odds ratios (ORs) and three sets of adjusted odds ratios (AORs) adjusted for selected sociodemographic, behavioral and health-related characteristics. All results accounted for NHIS sampling design variables. The analytic sample was 124,260 with 16.3% foreign-born adults. Among the foreign-born adults, 56% were from Central or South America, 22% from Asia, 13% from Europe, and 4% from Africa. Overall and after adjustment, hypertension prevalence was significantly higher among US-born adults than among foreign-born adults (AOR: 1.28, 95% CI: 1.21-1.36). By race/ethnicity, hypertension prevalence was higher among US-born non-Hispanic blacks than either foreign-born non-Hispanic blacks (AOR: 1.24, 95%CI: 1.02-1.50) or all Africa-born immigrants of any race/ethnicity [AOR: 1.45, 95% confidence interval (CI): 1.07-1.97]. Among foreign-born adults, duration of US residence was positively associated with the likelihood of hypertension. Hypertension prevalence was higher among US-born adults than among foreign-born adults and higher among US-born non-Hispanic blacks than in any other group. Among foreign-born adults, hypertension risk increased with the number of years they had lived in the United States.

School-Aged Children Born Preterm: Review of Functioning across Multiple Domains and Guidelines for Assessment

ERIC Educational Resources Information Center

Dempsey, Allison G.; Keller-Margulis, Milena; Mire, Sarah; Abrahamson, Catherine; Dutt, Sonia; Llorens, Ashlie; Payan, Anita

2015-01-01

Children born preterm are at risk for developmental deficits across multiple functional domains. As the rate of survival for preterm infants increases due to medical advancements, a greater understanding is needed for how to meet the needs of this growing population in schools. Because approximately 50-70% of children born preterm require…

Development of emotional and behavioral regulation in children born extremely preterm and very preterm: biological and social influences.

PubMed

Clark, Caron A C; Woodward, Lianne J; Horwood, L John; Moor, Stephanie

2008-01-01

This study describes the development of emotional and behavioral regulation in a regional cohort of children born extremely preterm (<28 weeks gestational age, n = 39), very preterm (<34 weeks gestational age, n = 56), and full term (n = 103). At 2 and 4 years, children born at younger gestational ages demonstrated poorer self-regulation across multiple contexts spanning observed interactions, formal cognitive testing, and parental report of child behavior at home. Among children born preterm, the 2 strongest predictors of impairments in self-regulation were the presence of moderate-to-severe cerebral white matter abnormalities on neonatal magnetic resonance and a less sensitive parenting style when children were aged 2 years. Findings support the importance of early neurological development and parenting for developing regulation in children born very preterm.

Approximate scaling properties of RNA free energy landscapes

NASA Technical Reports Server (NTRS)

Baskaran, S.; Stadler, P. F.; Schuster, P.

1996-01-01

RNA free energy landscapes are analysed by means of "time-series" that are obtained from random walks restricted to excursion sets. The power spectra, the scaling of the jump size distribution, and the scaling of the curve length measured with different yard stick lengths are used to describe the structure of these "time series". Although they are stationary by construction, we find that their local behavior is consistent with both AR(1) and self-affine processes. Random walks confined to excursion sets (i.e., with the restriction that the fitness value exceeds a certain threshold at each step) exhibit essentially the same statistics as free random walks. We find that an AR(1) time series is in general approximately self-affine on timescales up to approximately the correlation length. We present an empirical relation between the correlation parameter rho of the AR(1) model and the exponents characterizing self-affinity.

Are Canadian-born Major League Baseball players more likely to bat left-handed? A partial test of the hockey-influence on batting hypothesis.

PubMed

Cairney, John; Chirico, Daniele; Li, Yao-Chuen; Bremer, Emily; Graham, Jeffrey D

2018-01-01

It has been suggested that Canadian-born Major League Baseball (MLB) players are more likely to bat left-handed, possibly owing to the fact that they learn to play ice hockey before baseball, and that there is no clear hand-preference when shooting with a hockey stick; approximately half of all ice hockey players shoot left. We constructed a database on active (i.e., October, 2016) MLB players from four countries/regions based on place of birth (Canada, United States of America [USA], Dominican Republic and South Asia [i.e., Japan, Taiwan and South Korea]), including information on which hand they use to bat and throw. We also extracted information on all Canadian-born MLB players, dating back to 1917. Our results confirm that the proportion of left-handed batters born in Canada is higher when compared to the other countries selected; also, since 1917, the proportion of Canadian MLB players who bat left has been consistently higher than the league average. We also compared the proportion of left-handed batters in Canada with players born in states in the USA grouped into high, average and low based on hockey participation. The proportion of MLB players born in states with a high level of hockey participation were more likely to bat left, although the differences were significant at trend level only (p < .10). Lastly, we found that while Canadians were more likely to bat left-handed, this did not correspond with a greater left-hand dominance, as determined by throwing hand. In conclusion, the present study confirms that Canadian-born MLB players are more likely to bat left-handed when compared to American, Dominican Republic and South Asian-born MLB players, providing partial support for the hockey influence on batting hypothesis.

Proton scattering by short lived sulfur isotopes

NASA Astrophysics Data System (ADS)

Maréchal, F.; Suomijärvi, T.; Blumenfeld, Y.; Azhari, A.; Bauge, E.; Bazin, D.; Brown, J. A.; Cottle, P. D.; Delaroche, J. P.; Fauerbach, M.; Girod, M.; Glasmacher, T.; Hirzebruch, S. E.; Jewell, J. K.; Kelley, J. H.; Kemper, K. W.; Mantica, P. F.; Morrissey, D. J.; Riley, L. A.; Scarpaci, J. A.; Scheit, H.; Steiner, M.

1999-09-01

Elastic and inelastic proton scattering has been measured in inverse kinematics on the unstable nucleus 40S. A phenomenological distorted wave Born approximation analysis yields a quadrupole deformation parameter β2=0.35+/-0.05 for the 2+1 state. Consistent phenomenological and microscopic proton scattering analyses have been applied to all even-even sulfur isotopes from A=32 to A=40. The second analysis used microscopic collective model densities and a modified Jeukenne-Lejeune-Mahaux nucleon-nucleon effective interaction. This microscopic analysis suggests the presence of a neutron skin in the heavy sulfur isotopes. The analysis is consistent with normalization values for λv and λw of 0.95 for both the real and imaginary parts of the Jeukenne-Lejeune-Mahaux potential.

Gravitational corrections to light propagation in a perturbed FLRW universe and corresponding weak-lensing spectra

NASA Astrophysics Data System (ADS)

Cuesta-Lazaro, Carolina; Quera-Bofarull, Arnau; Reischke, Robert; Schäfer, Björn Malte

2018-06-01

When the gravitational lensing of the large-scale structure is calculated from a cosmological model a few assumptions enter: (i) one assumes that the photons follow unperturbed background geodesics, which is usually referred to as the Born approximation, (ii) the lenses move slowly, (iii) the source-redshift distribution is evaluated relative to the background quantities, and (iv) the lensing effect is linear in the gravitational potential. Even though these approximations are small individually they could sum up, especially since they include local effects such as the Sachs-Wolfe and peculiar motion, but also non-local ones like the Born approximation and the integrated Sachs-Wolfe effect. In this work, we will address all points mentioned and perturbatively calculate the effect on a tomographic cosmic shear power spectrum of each effect individually as well as all cross-correlations. Our findings show that each effect is at least 4-5 orders of magnitude below the leading order lensing signal. Finally, we sum up all effects to estimate the overall impact on parameter estimation by a future cosmological weak-lensing survey such as Euclid in a wcold dark matter cosmology with parametrization Ωm, σ8, ns, h, w0, and wa, using five tomographic bins. We consistently find a parameter bias of 10-5, which is therefore completely negligible for all practical purposes, confirming that other effects such as intrinsic alignments, magnification bias and uncertainties in the redshift distribution will be the dominant systematic source in future surveys.

Self-consistent treatment of electrostatics in molecular DNA braiding through external forces.

PubMed

Lee, Dominic J

2014-06-01

In this paper we consider a physical system in which two DNA molecules braid about each other. The distance between the two molecular ends, on either side of the braid, is held at a distance much larger than supercoiling radius of the braid. The system is subjected to an external pulling force, and a moment that induces the braiding. In a model, developed for understanding such a system, we assume that each molecule can be divided into a braided and unbraided section. We also suppose that the DNA is nicked so that there is no constraint of the individual linking numbers of the molecules. Included in the model are steric and electrostatic interactions, thermal fluctuations of the braided and unbraided sections of the molecule, as well as the constraint on the braid linking (catenation) number. We compare two approximations used in estimating the free energy of the braided section. One is where the amplitude of undulations of one molecule with respect to the other is determined only by steric interactions. The other is a self-consistent determination of the mean-squared amplitude of these undulations. In this second approximation electrostatics should play an important role in determining this quantity, as suggested by physical arguments. We see that if the electrostatic interaction is sufficiently large there are indeed notable differences between the two approximations. We go on to test the self-consistent approximation-included in the full model-against experimental data for such a system, and we find good agreement. However, there seems to be a slight left-right-handed braid asymmetry in some of the experimental results. We discuss what might be the origin of this small asymmetry.

Auxiliary-fermion approach to critical fluctuations in the two-dimensional quantum antiferromagnetic Heisenberg model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brinckmann, Jan; Woelfle, Peter

2004-11-01

The nearest-neighbor quantum antiferromagnetic (AF) Heisenberg model for spin-1/2 on a two-dimensional square lattice is studied in the auxiliary-fermion representation. Expressing spin operators by canonical fermionic particles requires a constraint on the fermion charge Q{sub i}=1 on each lattice site i, which is imposed approximately through the thermal average. The resulting interacting fermion system is first treated in mean-field theory (MFT), which yields an AF ordered ground state and spin waves in quantitative agreement with conventional spin-wave theory. At finite temperature a self-consistent approximation beyond mean field is required in order to fulfill the Mermin-Wagner theorem. We first discuss amore » fully self-consistent approximation, where fermions are renormalized due to fluctuations of their spin density, in close analogy to FLEX. While static properties like the correlation length, {xi}(T){proportional_to}exp(aJ/T), come out correctly, the dynamical response lacks the magnon-like peaks which would reflect the appearance of short-range order at low T. This drawback, which is caused by overdamping, is overcome in a 'minimal self-consistent approximation' (MSCA), which we derive from the equations of motion. The MSCA features dynamical scaling at small energy and temperature and is qualitatively correct both in the regime of order-parameter relaxation at long wavelengths {lambda}>{xi} and in the short-range-order regime at {lambda}<{xi}. We also discuss the impact of vertex corrections and the problem of pseudo-gap formation in the single-particle density of states due to long-range fluctuations. Finally we show that the (short-range) magnetic order in MFT and MSCA helps to fulfill the constraint on the local fermion occupancy.« less

Immigration, work and health in Spain: the influence of legal status and employment contract on reported health indicators

PubMed Central

Agudelo-Suárez, Andrés; Benavides, Fernando G.; Schenker, Marc; García, Ana M.; Benach, Joan; Delclos, Carlos; López-Jacob, María José; Ruiz-Frutos, Carlos; Ronda-Pérez, Elena; Porthé, Victoria

2010-01-01

Objective To analyze the relationship of legal status and employment conditions with health indicators in foreign-born and Spanish-born workers in Spain. Methods Cross-sectional study of 1,849 foreign-born and 509 Spanish-born workers (2008–2009, ITSAL Project). Considered employment conditions: permanent, temporary and no contract (foreign-born and Spanish-born); considered legal statuses: documented and undocumented (foreign-born). Joint relationships with self-rated health (SRH) and mental health (MH) were analyzed via logistical regression. Results When compared with male permanently contracted Spanish-born workers, worse health is seen in undocumented foreign-born, time in Spain ≤3 years (SRH aOR 2.68, 95% CI 1.09–6.56; MH aOR 2.26, 95% CI 1.15–4.42); in Spanish-born, temporary contracts (SRH aOR 2.40, 95% CI 1.04–5.53); and in foreign-born, temporary contracts, time in Spain >3 years (MH: aOR 1.96, 95% CI 1.13–3.38). In females, highest self-rated health risks are in foreign-born, temporary contracts (aOR 2.36, 95% CI 1.13–4.91) and without contracts, time in Spain >3 years (aOR 4.63, 95% CI 1.95–10.97). Conclusions Contract type is a health determinant in both foreign-born and Spanish-born workers. This study offers an uncommon exploration of undocumented migration and raises methodological issues to consider in future research. PMID:20401513

Compilation of Pilot Personality Norms

DTIC Science & Technology

2011-07-01

Relationships (BOR-N) Identifies individuals who report a history of involvement in unstable relationships. .63 Self - Harm (BOR-S) Identifies individuals who...Negative Relationships (BOR-N) 44.89 7.81 47.73 7.91 45.06 7.84 Self - Harm (BOR-S) 44.89 7.17 43.61 6.84 44.82 7.16 Antisocial Features (ANT) 51.89

Self-Regulation in Children Born with Extremely Low Birth Weight at 2 Years Old: A Comparison Study

ERIC Educational Resources Information Center

Lynn, Lisa N.; Cuskelly, Monica; Gray, Peter H.; O'Callaghan, Michael J.

2012-01-01

Survival rates for children born with extremely low birth weight (ELBW) are increasing; however, many of these children experience later problems with learning. This study adopted an integrated approach to these problems, involving the self-regulatory tasks of inhibition and delay of gratification and relevant individual factors including…

A different look at the epidemiological paradox: self-rated health, perceived social cohesion, and neighborhood immigrant context.

PubMed

Bjornstrom, Eileen E S; Kuhl, Danielle C

2014-11-01

We use data from Waves 1 and 2 of the Los Angeles Family and Neighborhood Survey to examine the effects of neighborhood immigrant concentration, race-ethnicity, nativity, and perceived cohesion on self-rated physical health. We limit our sample to adults whose addresses do not change between waves in order to explore neighborhood effects. Foreign-born Latinos were significantly less likely to report fair or poor health than African Americans and U.S.-born whites, but did not differ from U.S.-born Latinos. The main effect of immigrant concentration was not significant, but it interacted with nativity status to predict health: U.S.-born Latinos benefited more from neighborhood immigrant concentration than foreign-born Latinos. Perceived cohesion predicted health but immigrant concentration did not moderate the effect. Finally, U.S.-born Latinos differed from others in the way cohesion is associated with their health. Results are discussed within the framework of the epidemiological paradox. Copyright © 2014 Elsevier Ltd. All rights reserved.

Salecan Enhances the Activities of β-1,3-Glucanase and Decreases the Biomass of Soil-Borne Fungi

PubMed Central

Chen, Yunmei; Xu, Haiyang; Zhou, Mengyi; Wang, Yang; Wang, Shiming; Zhang, Jianfa

2015-01-01

Salecan, a linear extracellular polysaccharide consisting of β-1,3-D-glucan, has potential applications in the food, pharmaceutical and cosmetic industries. The objective of this study was to evaluate the effects of salecan on soil microbial communities in a vegetable patch. Compositional shifts in the genetic structure of indigenous soil bacterial and fungal communities were monitored using culture-dependent dilution plating, culture-independent PCR-denaturing gradient gel electrophoresis (DGGE) and quantitative PCR. After 60 days, soil microorganism counts showed no significant variation in bacterial density and a marked decrease in the numbers of fungi. The DGGE profiles revealed that salecan changed the composition of the microbial community in soil by increasing the amount of Bacillus strains and decreasing the amount of Fusarium strains. Quantitative PCR confirmed that the populations of the soil-borne fungi Fusarium oxysporum and Trichoderma spp. were decreased approximately 6- and 2-fold, respectively, in soil containing salecan. This decrease in the amount of fungi can be explained by salecan inducing an increase in the activities of β-1,3-glucanase in the soil. These results suggest the promising application of salecan for biological control of pathogens of soil-borne fungi. PMID:26247592

Dynamics and Self-consistent Chaos in a Mean Field Hamiltonian Model

NASA Astrophysics Data System (ADS)

del-Castillo-Negrete, Diego

We study a mean field Hamiltonian model that describes the collective dynamics of marginally stable fluids and plasmas in the finite N and N-> infty kinetic limit (where N is the number of particles). The linear stability of equilibria in the kinetic model is studied as well as the initial value problem including Landau damping . Numerical simulations show the existence of coherent, rotating dipole states. We approximate the dipole as two macroparticles and show that the N=2 limit has a family of rotating integrable solutions that provide an accurate description of the dynamics. We discuss the role of self-consistent Hamiltonian chaos in the formation of coherent structures, and discuss a mechanism of "violent" mixing caused by a self-consistent elliptic-hyperbolic bifurcation in phase space.

CONSISTENCY AND THE FIFTH VIRIAL COEFFICIENT FOR A HARD-SPHERE GAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cole, G.H.A.

1962-03-15

The modified superposition approximation g(/sup 3/)(r,s,t) = g(.syo 2)(r/ sup 2/g(/sup 2/)(s)g(/sup 2/)(t)STAl + X/sub 1/n + X/sub 2/n/sup 2/!(where g/sup (3)/si the triplet distribution, g(/sup 2/) the pair distribution, n the number density, and (r,s,t) are the particle separation distances) is used in conjunction with the Born-Green-Yvon equation of the classical theory of fluids in the calculation of the fifth virial coefficient E for a gas of hard spheres. The values of E derived directly from the virial theorem and alternatively from compressibility arguments are reconciled through a suitable choice of X/sub 2/. On the assumption X/sub i/ =more » constant it is found for hard spheres that X/sub 1/ = 0.1014b and X/sub 2/ = -0.0424b/sub 2/ (b = four times a molecular volume) ensures consistency as far as the fifth virial coefficient. The consistent value of E under this approximation is +0.0242b/sup 4/. The validity of the arguments is considered. (auth)« less

Recovery of singularities from a backscattering Born approximation for a biharmonic operator in 3D

NASA Astrophysics Data System (ADS)

Tyni, Teemu

2018-04-01

We consider a backscattering Born approximation for a perturbed biharmonic operator in three space dimensions. Previous results on this approach for biharmonic operator use the fact that the coefficients are real-valued to obtain the reconstruction of singularities in the coefficients. In this text we drop the assumption about real-valued coefficients and also establish the recovery of singularities for complex coefficients. The proof uses mapping properties of the Radon transform.

Solvent effects in time-dependent self-consistent field methods. I. Optical response calculations

DOE PAGES

Bjorgaard, J. A.; Kuzmenko, V.; Velizhanin, K. A.; ...

2015-01-22

In this study, we implement and examine three excited state solvent models in time-dependent self-consistent field methods using a consistent formalism which unambiguously shows their relationship. These are the linear response, state specific, and vertical excitation solvent models. Their effects on energies calculated with the equivalent of COSMO/CIS/AM1 are given for a set of test molecules with varying excited state charge transfer character. The resulting solvent effects are explained qualitatively using a dipole approximation. It is shown that the fundamental differences between these solvent models are reflected by the character of the calculated excitations.

Self-consistent ab initio Calculations for Photoionization and Electron-Ion Recombination Using the R-Matrix Method

NASA Astrophysics Data System (ADS)

Nahar, S. N.

2003-01-01

Most astrophysical plasmas entail a balance between ionization and recombination. We present new results from a unified method for self-consistent and ab initio calculations for the inverse processes of photoionization and (e + ion) recombination. The treatment for (e + ion) recombination subsumes the non-resonant radiative recombination and the resonant dielectronic recombination processes in a unified scheme (S.N. Nahar and A.K. Pradhan, Phys. Rev. A 49, 1816 (1994);H.L. Zhang, S.N. Nahar, and A.K. Pradhan, J.Phys.B, 32,1459 (1999)). Calculations are carried out using the R-matrix method in the close coupling approximation using an identical wavefunction expansion for both processes to ensure self-consistency. The results for photoionization and recombination cross sections may also be compared with state-of-the-art experiments on synchrotron radiation sources for photoionization, and on heavy ion storage rings for recombination. The new experiments display heretofore unprecedented detail in terms of resonances and background cross sections and thereby calibrate the theoretical data precisely. We find a level of agreement between theory and experiment at about 10% for not only the ground state but also the metastable states. The recent experiments therefore verify the estimated accuracy of the vast amount of photoionization data computed under the OP, IP and related works. features. Present work also reports photoionization cross sections including relativistic effects in the Breit-Pauli R-matrix (BPRM) approximation. Detailed features in the calculated cross sections exhibit the missing resonances due to fine structure. Self-consistent datasets for photoionization and recombination have so far been computed for approximately 45 atoms and ions. These are being reported in a continuing series of publications in Astrophysical J. Supplements (e.g. references below). These data will also be available from the electronic database TIPTOPBASE (http://heasarc.gsfc.nasa.gov)

Association of acculturation and country of origin with self-reported hypertension and diabetes in a heterogeneous Hispanic population.

PubMed

Rodriguez, Fátima; Hicks, LeRoi S; López, Lenny

2012-09-11

Hispanics are the fasting growing population in the U.S. and disproportionately suffer from chronic diseases such as hypertension and diabetes. Little is known about the complex interplay between acculturation and chronic disease prevalence in the growing and increasingly diverse Hispanic population. We explored the association between diabetes and hypertension prevalence among distinct U.S. Hispanic subgroups by country of origin and by degree of acculturation. We examined the adult participants in the 2001, 2003, 2005, and 2007 California Health Interview Survey (CHIS). Using weighted logistic regression stratified by nativity, we measured the association between country of origin and self-reported hypertension and diabetes adjusting for participants' demographics, insurance status, socio-economic status and degree of acculturation measured by citizenship, English language proficiency and the number of years of residence in the U.S. There were 33,633 self-identified Hispanics (foreign-born: 19,988; U.S.-born: 13,645). After multivariable adjustment, we found significant heterogeneity in self-reported hypertension and diabetes prevalence among Hispanic subgroups. Increasing years of U.S. residence was associated with increased disease prevalence. Among all foreign-born subgroups, only Mexicans reported lower odds of hypertension after adjustment for socioeconomic and acculturation factors. Both U.S.-born and foreign-born Mexicans had higher rates of diabetes as compared to non-Hispanic whites. We found significant heterogeneity among Hispanics in self-reported rates of hypertension and diabetes by acculturation and country of origin. Our findings highlight the importance of disaggregation of Hispanics by country of origin and acculturation factors whenever possible.

Early developmental influences on self-esteem trajectories from adolescence through adulthood: Impact of birth weight and motor skills.

PubMed

Poole, Kristie L; Schmidt, Louis A; Ferro, Mark A; Missiuna, Cheryl; Saigal, Saroj; Boyle, Michael H; Van Lieshout, Ryan J

2018-02-01

While the trajectory of self-esteem from adolescence to adulthood varies from person to person, little research has examined how differences in early developmental processes might affect these pathways. This study examined how early motor skill development interacted with preterm birth status to predict self-esteem from adolescence through the early 30s. We addressed this using the oldest known, prospectively followed cohort of extremely low birth weight (<1000 g) survivors (N = 179) and normal birth weight controls (N = 145) in the world, born between 1977 and 1982. Motor skills were measured using a performance-based assessment at age 8 and a retrospective self-report, and self-esteem was reported during three follow-up periods (age 12-16, age 22-26, and age 29-36). We found that birth weight status moderated the association between early motor skills and self-esteem. Stable over three decades, the self-esteem of normal birth weight participants was sensitive to early motor skills such that those with poorer motor functioning manifested lower self-esteem, while those with better motor skills manifested higher self-esteem. Conversely, differences in motor skill development did not affect the self-esteem from adolescence to adulthood in individuals born at extremely low birth weight. Early motor skill development may exert differential effects on self-esteem, depending on whether one is born at term or prematurely.

Inferences of the deep solar meridional flow

NASA Astrophysics Data System (ADS)

Böning, Vincent G. A.

2017-10-01

Understanding the solar meridional flow is important for uncovering the origin of the solar activity cycle. Yet, recent helioseismic estimates of this flow have come to conflicting conclusions in deeper layers of the solar interior, i.e., at depths below about 0.9 solar radii. The aim of this thesis is to contribute to a better understanding of the deep solar meridional flow. Time-distance helioseismology is the major method for investigating this flow. In this method, travel times of waves propagating between pairs of locations on the solar surface are measured. Until now, the travel-time measurements have been modeled using the ray approximation, which assumes that waves travel along infinitely thin ray paths between these locations. In contrast, the scattering of the full wave field in the solar interior due to the flow is modeled in first order by the Born approximation. It is in general a more accurate model of the physics in the solar interior. In a first step, an existing model for calculating the sensitivity of travel-time measurements to solar interior flows using the Born approximation is extended from Cartesian to spherical geometry. The results are succesfully compared to the Cartesian ones and are tested for self-consistency. In a second step, the newly developed model is validated using an existing numerical simulation of linear wave propagation in the Sun. An inversion of artificial travel times for meridional flow shows excellent agreement for noiseless data and reproduces many features in the input flow profile in the case of noisy data. Finally, the new method is used to infer the deep meridional flow. I used Global Oscillation Network Group (GONG) data that were earlier analyzed using the ray approximation and I employed the same Substractive Optimized Local Averaging (SOLA) inversion technique as in the earlier study. Using an existing formula for the covariance of travel-time measurements, it is shown that the assumption of uncorrelated errors from earlier studies leads to errors in the inverted flows being underestimated by a factor of about two to four. The inverted meridional flow above about 0.85 solar radii confirms the earlier results from ray theory regarding the general pattern of the flow, especially regarding a shallow return flow at about 0.9 solar radii, with some differences in the magnitude of the flow. Below about 0.85 solar radii, the inversion result depends on the thresholds used in the singular value decomposition. One result is again similar to the original regarding its general single-cell shape. Other results show a multi-cell structure in the southern hemisphere with two or three cells stacked radially. However, both the single-cell and the multi-cell flow profiles are consistent with the measured travel times within the measurement errors. To reach an unambiguous conclusion on the meridional flow below about 0.85 solar radii, the errors in the measured travel times have to be decreased considerably in future studies. For now, I conclude that the existing controversy of recent measurements of the deep meridional flow is relaxed by properly taking the associated errors into account.

Al{sub 4}SiC{sub 4} wurtzite crystal: Structural, optoelectronic, elastic, and piezoelectric properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pedesseau, L., E-mail: laurent.pedesseau@insa-rennes.fr, E-mail: jacky.even@insa-rennes.fr; Even, J., E-mail: laurent.pedesseau@insa-rennes.fr, E-mail: jacky.even@insa-rennes.fr; Durand, O.

New experimental results supported by theoretical analyses are proposed for aluminum silicon carbide (Al{sub 4}SiC{sub 4}). A state of the art implementation of the density functional theory is used to analyze the experimental crystal structure, the Born charges, the elastic properties, and the piezoelectric properties. The Born charge tensor is correlated to the local bonding environment for each atom. The electronic band structure is computed including self-consistent many-body corrections. Al{sub 4}SiC{sub 4} material properties are compared to other wide band gap wurtzite materials. From a comparison between an ellipsometry study of the optical properties and theoretical results, we conclude thatmore » the Al{sub 4}SiC{sub 4} material has indirect and direct band gap energies of about 2.5 eV and 3.2 eV, respectively.« less

Doubly self-consistent field theory of grafted polymers under simple shear in steady state.

PubMed

Suo, Tongchuan; Whitmore, Mark D

2014-03-21

We present a generalization of the numerical self-consistent mean-field theory of polymers to the case of grafted polymers under simple shear. The general theoretical framework is presented, and then applied to three different chain models: rods, Gaussian chains, and finitely extensible nonlinear elastic (FENE) chains. The approach is self-consistent at two levels. First, for any flow field, the polymer density profile and effective potential are calculated self-consistently in a manner similar to the usual self-consistent field theory of polymers, except that the calculation is inherently two-dimensional even for a laterally homogeneous system. Second, through the use of a modified Brinkman equation, the flow field and the polymer profile are made self-consistent with respect to each other. For all chain models, we find that reasonable levels of shear cause the chains to tilt, but it has very little effect on the overall thickness of the polymer layer, causing a small decrease for rods, and an increase of no more than a few percent for the Gaussian and FENE chains. Using the FENE model, we also probe the individual bond lengths, bond correlations, and bond angles along the chains, the effects of the shear on them, and the solvent and bonded stress profiles. We find that the approximations needed within the theory for the Brinkman equation affect the bonded stress, but none of the other quantities.

The Dynamics of Massive Starless Cores with ALMA

NASA Astrophysics Data System (ADS)

Tan, Jonathan C.; Kong, Shuo; Butler, Michael J.; Caselli, Paola; Fontani, Francesco

2013-12-01

How do stars that are more massive than the Sun form, and thus how is the stellar initial mass function (IMF) established? Such intermediate- and high-mass stars may be born from relatively massive pre-stellar gas cores, which are more massive than the thermal Jeans mass. The turbulent core accretion model invokes such cores as being in approximate virial equilibrium and in approximate pressure equilibrium with their surrounding clump medium. Their internal pressure is provided by a combination of turbulence and magnetic fields. Alternatively, the competitive accretion model requires strongly sub-virial initial conditions that then lead to extensive fragmentation to the thermal Jeans scale, with intermediate- and high-mass stars later forming by competitive Bondi-Hoyle accretion. To test these models, we have identified four prime examples of massive (~100 M ⊙) clumps from mid-infrared extinction mapping of infrared dark clouds. Fontani et al. found high deuteration fractions of N2H+ in these objects, which are consistent with them being starless. Here we present ALMA observations of these four clumps that probe the N2D+ (3-2) line at 2.''3 resolution. We find six N2D+ cores and determine their dynamical state. Their observed velocity dispersions and sizes are broadly consistent with the predictions of the turbulent core model of self-gravitating, magnetized (with Alfvén Mach number mA ~ 1) and virialized cores that are bounded by the high pressures of their surrounding clumps. However, in the most massive cores, with masses up to ~60 M ⊙, our results suggest that moderately enhanced magnetic fields (so that mA ~= 0.3) may be needed for the structures to be in virial and pressure equilibrium. Magnetically regulated core formation may thus be important in controlling the formation of massive cores, inhibiting their fragmentation, and thus helping to establish the stellar IMF.

Immigration, Suicidal Ideation and Deliberate Self-Injury in the Boston Youth Survey 2006

PubMed Central

Borges, Guilherme; Azrael, Deborah; Almeida, Joanna; Johnson, Renee M.; Molnar, Beth E.; Hemenway, David; Miller, Matthew

2018-01-01

The prevalence and immigration-related correlates of deliberate self-injury (DSI) and suicidal ideation (SI) were estimated in a sample of Boston public high school students in 2006. Compared with U.S.-born youth, immigrant youth were not at increased risk for DSI or SI, even if they had experienced discrimination due to their ancestry. By contrast, U.S.-born youth who reported having been discriminated against because of their ancestry had an increased risk of deliberate self-injury (odds ratio [OR] = 3.1, 95% confidence interval [CI] = 1.6–5.9) and suicidal ideation (OR = 2.1, 95% CI = 1.2–3.8). The combination of being U.S.-born and experiencing ancestry-based discrimination identifies youth at increased risk for suicidal behavior. PMID:21470295

Semiclassical approximation of the Wheeler-DeWitt equation: arbitrary orders and the question of unitarity

NASA Astrophysics Data System (ADS)

Kiefer, Claus; Wichmann, David

2018-06-01

We extend the Born-Oppenheimer type of approximation scheme for the Wheeler-DeWitt equation of canonical quantum gravity to arbitrary orders in the inverse Planck mass squared. We discuss in detail the origin of unitarity violation in this scheme and show that unitarity can be restored by an appropriate modification which requires back reaction from matter onto the gravitational sector. In our analysis, we heavily rely on the gauge aspects of the standard Born-Oppenheimer scheme in molecular physics.

Physical Fitness in Young Adults Born Preterm.

PubMed

Tikanmäki, Marjaana; Tammelin, Tuija; Sipola-Leppänen, Marika; Kaseva, Nina; Matinolli, Hanna-Maria; Miettola, Satu; Eriksson, Johan G; Järvelin, Marjo-Riitta; Vääräsmäki, Marja; Kajantie, Eero

2016-01-01

Young adults born preterm have higher levels of cardiometabolic risk factors than their term-born peers. Muscular and cardiorespiratory fitness have important cardiometabolic and other health benefits. We assessed muscular, cardiorespiratory, and self-rated fitness in preterm-born young adults. We studied unimpaired participants of the ESTER (Ennenaikainen syntymä ja aikuisiän terveys [Preterm Birth and Early-Life Programming of Adult Health and Disease]) birth cohort study at age 23.3 (SD: 1.2) years: 139 born early preterm (EPT; <34 weeks), 247 late preterm (LPT; 34-36 weeks), and 352 at term (control group). We measured muscular fitness with the number of modified push-ups performed in 40 seconds and maximal handgrip strength of the dominant hand, cardiovascular fitness with heart rate at the end of a 4-minute step test, and self-rated fitness. Data were analyzed with linear regression. Young adults born EPT (-0.8; 95% confidence interval: -1.5 to -0.1; adjusted for gender, age, and source cohort) and LPT (-0.8; -1.4 to -0.3) performed fewer modified push-ups than controls. Handgrip strength was 23.8 (0.9-46.8) N lower in EPT participants. Cardiorespiratory fitness, measured by submaximal step test, was similar. On a self-rated fitness scale (1-5), the EPT adults reported 0.2 (0.0-0.4) lower scores than controls. After adjustment for early-life confounders, the results remained. They attenuated after further adjustment for mediating factors. Young adults born EPT and LPT had lower muscular fitness than controls, which may predispose them to cardiometabolic and other chronic diseases. Adults born EPT also perceived themselves as less fit than controls. Copyright © 2016 by the American Academy of Pediatrics.

Approximate solution to the Hopf Phi equation for isotropic homogeneous fluid turbulence

NASA Technical Reports Server (NTRS)

Rosen, G.

1982-01-01

Consistent with the observed t to the -n decay laws for isotropic homogeneous turbulence and the form of the longitudinal correlation function f(r, t) for small r, the Hopf Phi equation is shown to be satisfied approximately by an asymptotic power series in t to the -n. This solution features a self-similar universal equilibrium functional which manifests Kolmogoroff-type scaling.

How will millennials impact freight flows in Texas? Final report.

DOT National Transportation Integrated Search

2017-01-01

Millennials (born between 1983 and 2000) represent approximately 25 percent of the population in the United States and already outnumber baby boomers (born between 1946 and 1964) in the current population (15,16,17). As young adults, millennials are ...

All-electron quasiparticle self-consistent GW band structures for SrTiO 3 including lattice polarization corrections in different phases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhandari, Churna; van Schilfgaarde, Mark; Kotani, Takao

The electronic band structure of SrTiO3 is investigated in the all-electron quasiparticle self-consistent GW (QSGW) approximation. Unlike previous pseudopotential-based QSGW or single-shot G0W0 calculations, the gap is found to be significantly overestimated compared to experiment. After putting in a correction for the underestimate of the screening by the random phase approximation in terms of a 0.8Σ approach, the gap is still overestimated. The 0.8Σ approach is discussed and justified in terms of various recent literature results including electron-hole corrections. Adding a lattice polarization correction (LPC) in the q→0 limit for the screening of W, agreement with experiment is recovered. Themore » LPC is alternatively estimated using a polaron model. Here, we apply our approach to the cubic and tetragonal phases as well as a hypothetical layered postperovskite structure and find that the local density approximation (LDA) to GW gap correction is almost independent of structure.« less

All-electron quasiparticle self-consistent GW band structures for SrTiO 3 including lattice polarization corrections in different phases

DOE PAGES

Bhandari, Churna; van Schilfgaarde, Mark; Kotani, Takao; ...

2018-01-23

The electronic band structure of SrTiO3 is investigated in the all-electron quasiparticle self-consistent GW (QSGW) approximation. Unlike previous pseudopotential-based QSGW or single-shot G0W0 calculations, the gap is found to be significantly overestimated compared to experiment. After putting in a correction for the underestimate of the screening by the random phase approximation in terms of a 0.8Σ approach, the gap is still overestimated. The 0.8Σ approach is discussed and justified in terms of various recent literature results including electron-hole corrections. Adding a lattice polarization correction (LPC) in the q→0 limit for the screening of W, agreement with experiment is recovered. Themore » LPC is alternatively estimated using a polaron model. Here, we apply our approach to the cubic and tetragonal phases as well as a hypothetical layered postperovskite structure and find that the local density approximation (LDA) to GW gap correction is almost independent of structure.« less

Post-Newtonian and numerical calculations of the gravitational self-force for circular orbits in the Schwarzschild geometry

NASA Astrophysics Data System (ADS)

Blanchet, Luc; Detweiler, Steven; Le Tiec, Alexandre; Whiting, Bernard F.

2010-03-01

The problem of a compact binary system whose components move on circular orbits is addressed using two different approximation techniques in general relativity. The post-Newtonian (PN) approximation involves an expansion in powers of v/c≪1, and is most appropriate for small orbital velocities v. The perturbative self-force analysis requires an extreme mass ratio m1/m2≪1 for the components of the binary. A particular coordinate-invariant observable is determined as a function of the orbital frequency of the system using these two different approximations. The post-Newtonian calculation is pushed up to the third post-Newtonian (3PN) order. It involves the metric generated by two point particles and evaluated at the location of one of the particles. We regularize the divergent self-field of the particle by means of dimensional regularization. We show that the poles ∝(d-3)-1 appearing in dimensional regularization at the 3PN order cancel out from the final gauge invariant observable. The 3PN analytical result, through first order in the mass ratio, and the numerical self-force calculation are found to agree well. The consistency of this cross cultural comparison confirms the soundness of both approximations in describing compact binary systems. In particular, it provides an independent test of the very different regularization procedures invoked in the two approximation schemes.

Distorted-wave methods for electron capture in ion-atom collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burgdoerfer, J.; Taulbjerg, K.

1986-05-01

Distorted-wave methods for electron capture are discussed with emphasis on the surface term in the T matrix and on the properties of the associated integral equations. The surface term is generally nonvanishing if the distorted waves are sufficiently accurate to include parts of the considered physical process. Two examples are considered in detail. If distorted waves of the strong-potential Born-approximation (SPB) type are employed the surface term supplies the first-Born-approximation part of the T matrix. The surface term is shown to vanish in the continuum-distorted-wave (CDW) method. The integral kernel is in either case free of the dangerous disconnected termsmore » discussed by Greider and Dodd but the CDW theory is peculiar in the sense that its first-order approximation (CDW1) excludes a specific on-shell portion of the double-scattering term that is closely connected with the classical Thomas process. The latter is described by the second-order term in the CDW series. The distorted-wave Born approximation with SPB waves is shown to be free of divergences. In the limit of asymmetric collisions the DWB suggests a modification of the SPB approximation to avoid the divergence problem recently identified by Dewangan and Eichler.« less

Beyond the random-phase approximation for the electron correlation energy: the importance of single excitations.

PubMed

Ren, Xinguo; Tkatchenko, Alexandre; Rinke, Patrick; Scheffler, Matthias

2011-04-15

The random-phase approximation (RPA) for the electron correlation energy, combined with the exact-exchange (EX) energy, represents the state-of-the-art exchange-correlation functional within density-functional theory. However, the standard RPA practice--evaluating both the EX and the RPA correlation energies using Kohn-Sham (KS) orbitals from local or semilocal exchange-correlation functionals--leads to a systematic underbinding of molecules and solids. Here we demonstrate that this behavior can be corrected by adding a "single excitation" contribution, so far not included in the standard RPA scheme. A similar improvement can also be achieved by replacing the non-self-consistent EX total energy by the corresponding self-consistent Hartree-Fock total energy, while retaining the RPA correlation energy evaluated using KS orbitals. Both schemes achieve chemical accuracy for a standard benchmark set of noncovalent intermolecular interactions.

Ground-state energies and highest occupied eigenvalues of atoms in exchange-only density-functional theory

NASA Astrophysics Data System (ADS)

Li, Yan; Harbola, Manoj K.; Krieger, J. B.; Sahni, Viraht

1989-11-01

The exchange-correlation potential of the Kohn-Sham density-functional theory has recently been interpreted as the work required to move an electron against the electric field of its Fermi-Coulomb hole charge distribution. In this paper we present self-consistent results for ground-state total energies and highest occupied eigenvalues of closed subshell atoms as obtained by this formalism in the exchange-only approximation. The total energies, which are an upper bound, lie within 50 ppm of Hartree-Fock theory for atoms heavier than Be. The highest occupied eigenvalues, as a consequence of this interpretation, approximate well the experimental ionization potentials. In addition, the self-consistently calculated exchange potentials are very close to those of Talman and co-workers [J. D. Talman and W. F. Shadwick, Phys. Rev. A 14, 36 (1976); K. Aashamar, T. M. Luke, and J. D. Talman, At. Data Nucl. Data Tables 22, 443 (1978)].

Ground state properties of 3d metals from self-consistent GW approach

DOE PAGES

Kutepov, Andrey L.

2017-10-06

The self consistent GW approach (scGW) has been applied to calculate the ground state properties (equilibrium Wigner–Seitz radius S WZ and bulk modulus B) of 3d transition metals Sc, Ti, V, Fe, Co, Ni, and Cu. The approach systematically underestimates S WZ with average relative deviation from the experimental data of about 1% and it overestimates the calculated bulk modulus with relative error of about 25%. We show that scGW is superior in accuracy as compared to the local density approximation but it is less accurate than the generalized gradient approach for the materials studied. If compared to the randommore » phase approximation, scGW is slightly less accurate, but its error for 3d metals looks more systematic. Lastly, the systematic nature of the deviation from the experimental data suggests that the next order of the perturbation theory should allow one to reduce the error.« less

Ground state properties of 3d metals from self-consistent GW approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kutepov, Andrey L.

The self consistent GW approach (scGW) has been applied to calculate the ground state properties (equilibrium Wigner–Seitz radius S WZ and bulk modulus B) of 3d transition metals Sc, Ti, V, Fe, Co, Ni, and Cu. The approach systematically underestimates S WZ with average relative deviation from the experimental data of about 1% and it overestimates the calculated bulk modulus with relative error of about 25%. We show that scGW is superior in accuracy as compared to the local density approximation but it is less accurate than the generalized gradient approach for the materials studied. If compared to the randommore » phase approximation, scGW is slightly less accurate, but its error for 3d metals looks more systematic. Lastly, the systematic nature of the deviation from the experimental data suggests that the next order of the perturbation theory should allow one to reduce the error.« less

Extended Lagrangian formulation of charge-constrained tight-binding molecular dynamics.

PubMed

Cawkwell, M J; Coe, J D; Yadav, S K; Liu, X-Y; Niklasson, A M N

2015-06-09

The extended Lagrangian Born-Oppenheimer molecular dynamics formalism [Niklasson, Phys. Rev. Lett., 2008, 100, 123004] has been applied to a tight-binding model under the constraint of local charge neutrality to yield microcanonical trajectories with both precise, long-term energy conservation and a reduced number of self-consistent field optimizations at each time step. The extended Lagrangian molecular dynamics formalism restores time reversal symmetry in the propagation of the electronic degrees of freedom, and it enables the efficient and accurate self-consistent optimization of the chemical potential and atomwise potential energy shifts in the on-site elements of the tight-binding Hamiltonian that are required when enforcing local charge neutrality. These capabilities are illustrated with microcanonical molecular dynamics simulations of a small metallic cluster using an sd-valent tight-binding model for titanium. The effects of weak dissipation on the propagation of the auxiliary degrees of freedom for the chemical potential and on-site Hamiltonian matrix elements that is used to counteract the accumulation of numerical noise during trajectories was also investigated.

Reports of self-rated health by citizenship and homeownership, United States 2000-2010.

PubMed

Miranda, Patricia Y; Reyes, Adriana; Hudson, Darrell; Yao, Nengliang; Bleser, William K; Amy Snipes, S; BeLue, Rhonda

2017-07-01

Citizenship facilitates home ownership, which promotes access to additional resources and structures social context, factors that improve the health of individuals and communities. The objective of this study was to examine whether citizenship moderated the association between homeownership and self-rated health. We used multivariate logistic regression models and propensity score matching techniques to examine this association using pooled years 2000-2010 of the Medical Expenditure Panel Survey data linked with the National Health Interview Survey to examine U.S. adults aged 18 and older (N=170,429). Rates of fair/poor health among homeowners vs. non-homeowners were comparable for foreign-born non-citizens. However, native- and foreign-born citizen non-homeowners showed significantly higher rates of reporting fair/poor health, with native-born citizens having the highest rates of poor health. While homeownership is protective for self-rated health, not meeting the "American Dream" of home ownership may be embodied more in the health of native-born citizens as "failure" and translate into poorer self-rated health. However, the economic privileges of homeownership and its association with better self-rated health are limited to citizens. Non-citizens may be disadvantaged despite socioeconomic position, particularly wealth as considered by homeownership, placing citizenship at the forefront as the most proximate and important burden besides socioeconomic status that needs further investigation as a fundamental health determinant. Copyright © 2017 Elsevier Inc. All rights reserved.

Cultural Impact on SAD: Social Anxiety Disorder among Ethiopian and Former Soviet Union Immigrants to Israel, in Comparison to Native-born Israelis.

PubMed

Hasenson-Atzmon, Kelly; Marom, Sofi; Sofer, Tamar; Lev-Ari, Lilac; Youngmann, Rafael; Hermesh, Haggai; Kushnir, Jonathan

2016-01-01

Social Anxiety Disorder (SAD) is linked to social norms and role expectations which are culture dependent, such as the construal of one's self as independent or interdependent in relation to others. The current study is the first to examine SAD symptoms among Ethiopian and former Soviet Union immigrants to Israel compared to a sample of native Israelis. We investigated the relationship between SAD, ethnicity and independent/ interdependent self-construals. A total of 261 students (151 native-born Israelis, 60 Ethiopian immigrants and 50 students from the former USSR) were administrated the Liebowitz Scale (LSAS), the Self-construal Scale (SCS), Beck Depression Inventory (BDI) and a socio-demographic questionnaire. Ethiopians exhibited highest SAD scores while no differences were found between the FSU immigrants and native-born Israelis. Additionally, Ethiopians and native-born Israeli students exhibited similar high interdependence scores. Finally, SAD scores were predicted by gender, origin, independent and interdependent self-construals. Immigration per se is not a universal risk factor of SAD and ethnological-cultural factors do contribute specifically to SAD. A possible psychological mediator between culture and the susceptibility to SAD are the interdependence and independent self-construals. When treating immigrants, clinicians and health care providers are advised to consider the effect of cultural influence on the mental well-being and integration process of immigrants in to their host country.

Acculturation and sleep among a multiethnic sample of women: the Study of Women's Health Across the Nation (SWAN).

PubMed

Hale, Lauren; Troxel, Wendy M; Kravitz, Howard M; Hall, Martica H; Matthews, Karen A

2014-02-01

Mexican immigrants to the United States report longer sleep duration and fewer sleep complaints than their US-born counterparts. To investigate whether this effect extends to other immigrant groups, we examined whether the prevalence of self-reported sleep complaints is higher among US-born Hispanic/Latina, Chinese, and Japanese immigrant women compared to their first-generation immigrant ethnic counterparts as well as to US-born whites. We examined whether these associations persisted after adjusting for sociodemographic and health characteristics and whether acculturation mediated the effects. Cross-sectional observational study. Multisite study in Oakland, CA; Los Angeles, CA; and Newark, NJ. Hispanic/Latina (n = 196), Chinese (n = 228), Japanese (n = 271) and non-Hispanic white (n = 485) women (mean age = 46 y, range 42-52 y) participating in the Study of Women's Health Across the Nation (SWAN); 410 or 59.0% of the nonwhites were first-generation immigrants. None. Questionnaires were used to assess sleep complaints, race/ethnicity, immigrant status, language acculturation (use of English language), and sociodemographic and health variables. Approximately 25% of first-generation immigrant women reported sleep complaints compared to 37% of those who were US-born nonwhites and 42% of US-born whites. Multivariable adjusted logistic regression analyses showed that US-born nonwhites had higher odds of reporting any sleep complaints (odds ratio = 2.1, 95% confidence interval [CI] 1.5-3.0), compared to first-generation immigrants. Women with higher levels of language acculturation had greater odds of reporting any sleep complaint compared to those with less language acculturation. Adjustment for language acculturation mediated 40.4% (95% CI 28.5-69.8) of the association between immigrant status and any sleep complaint. When results were stratified by race/ethnicity, significant mediation effects of acculturation were only found for Hispanic/Latina and Japanese women, but not for Chinese women. US-born Hispanic/Latina, Chinese, and Japanese immigrants were more likely to report sleep complaints than their first-generation ethnic counterparts, a finding largely explained by language acculturation and unmeasured factors associated with language acculturation.

Association between birth order and emergency room visits and acute hospital admissions following pediatric vaccination: a self-controlled study.

PubMed

Hawken, Steven; Kwong, Jeffrey C; Deeks, Shelley L; Crowcroft, Natasha S; Ducharme, Robin; Manuel, Douglas G; Wilson, Kumanan

2013-01-01

We investigated the association between a child's birth order and emergency room (ER) visits and hospital admissions following 2-,4-,6- and 12-month pediatric vaccinations. We included all children born in Ontario between April 1(st), 2006 and March 31(st), 2009 who received a qualifying vaccination. We identified vaccinations, ER visits and admissions using health administrative data housed at the Institute for Clinical Evaluative Sciences. We used the self-controlled case series design to compare the relative incidence (RI) of events among 1(st)-born and later-born children using relative incidence ratios (RIR). For the 2-month vaccination, the RIR for 1(st)-borns versus later-born children was 1.37 (95% CI: 1.19-1.57), which translates to 112 additional events/100,000 vaccinated. For the 4-month vaccination, the RIR for 1(st)-borns vs. later-borns was 1.70 (95% CI: 1.45-1.99), representing 157 additional events/100,000 vaccinated. At 6 months, the RIR for 1(st) vs. later-borns was 1.27 (95% CI: 1.09-1.48), or 77 excess events/100,000 vaccinated. At the 12-month vaccination, the RIR was 1.11 (95% CI: 1.02-1.21), or 249 excess events/100,000 vaccinated. Birth order is associated with increased incidence of ER visits and hospitalizations following vaccination in infancy. 1(st)-born children had significantly higher relative incidence of events compared to later-born children.

First-row diatomics: Calculation of the geometry and energetics using self-consistent gradient-functional approximations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kutzler, F.W.; Painter, G.S.

1992-02-15

A fully self-consistent series of nonlocal (gradient) density-functional calculations has been carried out using the augmented-Gaussian-orbital method to determine the magnitude of gradient corrections to the potential-energy curves of the first-row diatomics, Li{sub 2} through F{sub 2}. Both the Langreth-Mehl-Hu and the Perdew-Wang gradient-density functionals were used in calculations of the binding energy, bond length, and vibrational frequency for each dimer. Comparison with results obtained in the local-spin-density approximation (LSDA) using the Vosko-Wilk-Nusair functional, and with experiment, reveals that bond lengths and vibrational frequencies are rather insensitive to details of the gradient functionals, including self-consistency effects, but the gradient correctionsmore » reduce the overbinding commonly observed in the LSDA calculations of first-row diatomics (with the exception of Li{sub 2}, the gradient-functional binding-energy error is only 50--12 % of the LSDA error). The improved binding energies result from a large differential energy lowering, which occurs in open-shell atoms relative to the diatomics. The stabilization of the atom arises from the use of nonspherical charge and spin densities in the gradient-functional calculations. This stabilization is negligibly small in LSDA calculations performed with nonspherical densities.« less

Response theory of the ergodic many-body delocalized phase: Keldysh Finkel'stein sigma models and the 10-fold way

NASA Astrophysics Data System (ADS)

Liao, Yunxiang; Levchenko, Alex; Foster, Matthew S.

2017-11-01

We derive the finite temperature Keldysh response theory for interacting fermions in the presence of quenched short-ranged disorder, as applicable to any of the 10 Altland-Zirnbauer classes in an Anderson delocalized phase with at least a U(1) continuous symmetry. In this formulation of the interacting Finkel'stein nonlinear sigma model, the statistics of one-body wave functions are encoded by the constrained matrix field, while physical correlations follow from the hydrodynamic density or spin response field, which decouples the interactions. Integrating out the matrix field first, we obtain weak (anti) localization and Altshuler-Aronov quantum conductance corrections from the hydrodynamic response function. This procedure automatically incorporates the correct infrared cutoff physics, and in particular gives the Altshuler-Aronov-Khmelnitsky (AAK) equations for dephasing of weak (anti)localization due to electron-electron collisions. We explicate the method by deriving known quantumcorrections in two dimensions for the symplectic metal class AII, as well as the spin-SU(2) invariant superconductor classes C and CI. We show that quantum conductance corrections due to the special modes at zero energy in nonstandard classes are automatically cut off by temperature, as previously expected, while the Wigner-Dyson class Cooperon modes that persist to all energies are cut by dephasing. We also show that for short-ranged interactions, the standard self-consistent solution for the dephasing rate is equivalent to a particular summation of diagrams via the self-consistent Born approximation. This should be compared to the corresponding AAK solution for long-ranged Coulomb interactions, which exploits the Markovian noise correlations induced by thermal fluctuations of the electromagnetic field. We discuss prospects for exploring the many-body localization transition as a dephasing catastrophe in short-range interacting models, as encountered by approaching from the ergodic side.

Thai Muslim adolescents' self, sexuality, and autonomy.

PubMed

Anderson, W W; Anderson, D D

1986-12-01

The focus of the study was an examination of the structure of the concept of self of Thai Muslim adolescents with whom research was conducted on their physical, social, and psychological development from 1982 to 1983. The self was defined as the related components of the physical self and the psychological self. A research strategy of fallibility reduction through a multiplicity of indexes was used based on six indexes of their formulation of self. The data were obtained from Nipa Island in Krabi province from 115 adolescents in 82 of the households located at the center of the island. 78 adolescents were used in testing the communalities of 29 attributes. Factor analysis (analysis of variance and multivariate analysis of variance) showed that there was little difference between the sexes except on Factor 1 (philandering, hippyish, boastful, and leading others astray) (p 0.05). Both sexes wanted to develop themselves to be less regarded as having the above attributes in the future; but the degree of desired change was more pronounced among males than among females (p 0.05). Males also scored themselves as being more philandering than did females (p 0.01). Regarding the issue of autonomous self, females expressed stronger desire than males to be oneself in their future self-orientation (p 0.05). Age was categorized into four groups: 10.0-13.9 years old, 14.0-16.9 years old, 17.0-19.9 years old, and 20.0-22.9 years old. Birth order was coded as first-born, middle-born, and last-born. The second age group rated themselves higher than the other age groups on Factor 3 attributes (swaggering, indolent, and flirtatious). Middle-born sons were more imbued with a negative set of behavioral attributes on Factor 1, while last-born adolescents expressed the strongest desire to improve themselves regarding Factor 2 (gossipy, abusive, gullible, and leading others astray) (p = 0.060). Early maturers, who had the early onset of puberty, expressed more negative behaviors contained in Factor 1 (p 0.01).

Health-related quality of life and emotional and behavioral difficulties after extreme preterm birth: developmental trajectories.

PubMed

Vederhus, Bente Johanne; Eide, Geir Egil; Natvig, Gerd Karin; Markestad, Trond; Graue, Marit; Halvorsen, Thomas

2015-01-01

Background. Knowledge of long-term health related outcomes in contemporary populations born extremely preterm (EP) is scarce. We aimed to explore developmental trajectories of health-related quality of life (HRQoL) and behavior from mid-childhood to early adulthood in extremely preterm and term-born individuals. Methods. Subjects born at gestational age ≤28 weeks or with birth weight ≤1,000 g within a region of Norway in 1991-92 and matched term-born control subjects were assessed at 10 and 18 years. HRQoL was measured with the Child Health Questionnaire (CHQ) and behavior with the Child Behavior Checklist (CBCL), using parent assessment at both ages and self-assessment at 18 years. Results. All eligible EP (n = 35) and control children participated at 10 years, and 31 (89%) and 29 (83%) at 18 years. At 10 years, the EP born boys were given significantly poorer scores by their parents than term-born controls on most CHQ and CBCL scales, but the differences were minor at 18 years; i.e., significant improvements had occurred in several CHQ (self-esteem, general health and parental impact-time) and CBCL (total problem, internalizing and anxious/depressed) scales. For the girls, the differences were smaller at 10 years and remained unchanged by 18 years. Emotional/behavioral difficulties at 10 years similarly predicted poorer improvement on CHQ-scales for both EP and term-born subjects at 18 years. Self-assessment of HRQoL and behavior at 18 years was similar in the EP and term-born groups on most scales. Conclusions. HRQoL and behavior improved towards adulthood for EP born boys, while the girls remained relatively similar, and early emotional and behavioral difficulties predicted poorer development in HRQoL through adolescence. These data indicate that gender and a longitudinal perspective should be considered when addressing health and wellbeing after extremely preterm birth.

Longitudinal Consistency in Self-Reported Age of First Vaginal Intercourse Among Young Adults

PubMed Central

Goldberg, Shoshana K.; Haydon, Abigail A.; Herring, Amy H.; Halpern, Carolyn T.

2014-01-01

We examined consistency in self-reports of age at first vaginal sex among 9,399 male and female respondents who participated in Waves III and IV (separated by approximately 7 years) of the National Longitudinal Study of Adolescent Health (Add Health). Respondents were coded as consistent if they reported an age at first vaginal intercourse at Wave IV that was within 1 year of the age they reported at Wave III. Sociodemographic, behavioral, and cognitive predictors of consistency were examined using bivariate and multivariate logistic regression. Overall, 85.43% of respondents were able to provide consistent reports. Among both males and females, consistency was associated with age, years since first vaginal intercourse, race/ethnicity, and lifetime number of other-sex partners in final multivariate models. Respondents who were older and had more recently had their first sexual experience were more likely to be consistent. For females only, those who reported a history of non-parental, physically forced sex were less likely to be consistent. Most young adults consistently report age at first vaginal intercourse, supporting the credibility of retrospective self-reports about salient sexual events such as timing of first vaginal intercourse. PMID:23237101

Validation of a New Measure of the Concept of Good Death among Taiwanese Children

ERIC Educational Resources Information Center

Yang, Shu Ching; Lai, Sih-yi

2012-01-01

The purpose of this study was to develop and validate an instrument to measure dimensions of the concept of a good death held by Taiwanese children. The sample consisted of 1,698 Taiwanese children, approximately 12-14 years of age. Participants completed the self-administered Good Death Concept Scale (GDCS), which consists of 30 statements…

Temperature equilibration rate with Fermi-Dirac statistics.

PubMed

Brown, Lowell S; Singleton, Robert L

2007-12-01

We calculate analytically the electron-ion temperature equilibration rate in a fully ionized, weakly to moderately coupled plasma, using an exact treatment of the Fermi-Dirac electrons. The temperature is sufficiently high so that the quantum-mechanical Born approximation to the scattering is valid. It should be emphasized that we do not build a model of the energy exchange mechanism, but rather, we perform a systematic first principles calculation of the energy exchange. At the heart of this calculation lies the method of dimensional continuation, a technique that we borrow from quantum field theory and use in a different fashion to regulate the kinetic equations in a consistent manner. We can then perform a systematic perturbation expansion and thereby obtain a finite first-principles result to leading and next-to-leading order. Unlike model building, this systematic calculation yields an estimate of its own error and thus prescribes its domain of applicability. The calculational error is small for a weakly to moderately coupled plasma, for which our result is nearly exact. It should also be emphasized that our calculation becomes unreliable for a strongly coupled plasma, where the perturbative expansion that we employ breaks down, and one must then utilize model building and computer simulations. Besides providing different and potentially useful results, we use this calculation as an opportunity to explain the method of dimensional continuation in a pedagogical fashion. Interestingly, in the regime of relevance for many inertial confinement fusion experiments, the degeneracy corrections are comparable in size to the subleading quantum correction below the Born approximation. For consistency, we therefore present this subleading quantum-to-classical transition correction in addition to the degeneracy correction.

Branch-Based Model for the Diameters of the Pulmonary Airways: Accounting for Departures From Self-Consistency and Registration Errors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neradilek, Moni B.; Polissar, Nayak L.; Einstein, Daniel R.

2012-04-24

We examine a previously published branch-based approach to modeling airway diameters that is predicated on the assumption of self-consistency across all levels of the tree. We mathematically formulate this assumption, propose a method to test it and develop a more general model to be used when the assumption is violated. We discuss the effect of measurement error on the estimated models and propose methods that account for it. The methods are illustrated on data from MRI and CT images of silicone casts of two rats, two normal monkeys and one ozone-exposed monkey. Our results showed substantial departures from self-consistency inmore » all five subjects. When departures from selfconsistency exist we do not recommend using the self-consistency model, even as an approximation, as we have shown that it may likely lead to an incorrect representation of the diameter geometry. Measurement error has an important impact on the estimated morphometry models and needs to be accounted for in the analysis.« less

Self-consistent chaos in a mean-field Hamiltonian model of fluids and plasmas

NASA Astrophysics Data System (ADS)

del-Castillo-Negrete, D.; Firpo, Marie-Christine

2002-11-01

We present a mean-field Hamiltonian model that describes the collective dynamics of marginally stable fluids and plasmas. In plasmas, the model describes the self-consistent evolution of electron holes and clumps in phase space. In fluids, the model describes the dynamics of vortices with negative and positive circulation in shear flows. The mean-field nature of the system makes it a tractable model to study the dynamics of large degrees-of-freedom, coupled Hamiltonian systems. Here we focus in the role of self-consistent chaos in the formation and destruction of phase space coherent structures. Numerical simulations in the finite N and in the Narrow kinetic limit (where N is the number of particles) show the existence of coherent, rotating dipole states. We approximate the dipole as two macroparticles, and show that the N = 2 limit has a family of rotating integrable solutions described by a one degree-of-freedom nontwist Hamiltonian. The coherence of the dipole is explained in terms of a parametric resonance between the rotation frequency of the macroparticles and the oscillation frequency of the self-consistent mean field. For a class of initial conditions, the mean field exhibits a self-consistent, elliptic-hyperbolic bifurcation that leads to the destruction of the dipole and violent mixing of the phase space.

Skin Color and Self-Perceptions of Immigrant and U.S.-Born Latinas: The Moderating Role of Racial Socialization and Ethnic Identity

ERIC Educational Resources Information Center

Telzer, Eva H.; Vazquez Garcia, Heidie A.

2009-01-01

Research has increasingly identified race as a salient characteristic that affects one's life experiences and psychological well-being. However, little is known about how skin color affects the emotional health of Latinos. The present study examined how skin color relates to the self-perceptions of immigrant (N = 26) and U.S.-born (N = 55) Latina…

Effects of tick control by acaricide self-treatement of white-tailed deer on host-seeking tick infection prevalence and entomologic risk for Ixodes scapularis-borne pathogens

USDA-ARS?s Scientific Manuscript database

We evaluated the effects of tick control by acaricide self-treatment of white-tailed deer on the infection prevalence and entomologic risk for three I. scapularis-borne bacteria in host-seeking ticks. Ticks were collected from vegetation in areas treated with the ‘4-Poster’ device and from control a...

Telescopic multi-resolution augmented reality

NASA Astrophysics Data System (ADS)

Jenkins, Jeffrey; Frenchi, Christopher; Szu, Harold

2014-05-01

To ensure a self-consistent scaling approximation, the underlying microscopic fluctuation components can naturally influence macroscopic means, which may give rise to emergent observable phenomena. In this paper, we describe a consistent macroscopic (cm-scale), mesoscopic (micron-scale), and microscopic (nano-scale) approach to introduce Telescopic Multi-Resolution (TMR) into current Augmented Reality (AR) visualization technology. We propose to couple TMR-AR by introducing an energy-matter interaction engine framework that is based on known Physics, Biology, Chemistry principles. An immediate payoff of TMR-AR is a self-consistent approximation of the interaction between microscopic observables and their direct effect on the macroscopic system that is driven by real-world measurements. Such an interdisciplinary approach enables us to achieve more than multiple scale, telescopic visualization of real and virtual information but also conducting thought experiments through AR. As a result of the consistency, this framework allows us to explore a large dimensionality parameter space of measured and unmeasured regions. Towards this direction, we explore how to build learnable libraries of biological, physical, and chemical mechanisms. Fusing analytical sensors with TMR-AR libraries provides a robust framework to optimize testing and evaluation through data-driven or virtual synthetic simulations. Visualizing mechanisms of interactions requires identification of observable image features that can indicate the presence of information in multiple spatial and temporal scales of analog data. The AR methodology was originally developed to enhance pilot-training as well as `make believe' entertainment industries in a user-friendly digital environment We believe TMR-AR can someday help us conduct thought experiments scientifically, to be pedagogically visualized in a zoom-in-and-out, consistent, multi-scale approximations.

How important is self-consistency for the dDsC density dependent dispersion correction?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brémond, Éric; Corminboeuf, Clémence, E-mail: clemence.corminboeuf@epfl.ch; Golubev, Nikolay

2014-05-14

The treatment of dispersion interactions is ubiquitous but computationally demanding for seamless ab initio approaches. A highly popular and simple remedy consists in correcting for the missing interactions a posteriori by adding an attractive energy term summed over all atom pairs to standard density functional approximations. These corrections were originally based on atom pairwise parameters and, hence, had a strong touch of empiricism. To overcome such limitations, we recently proposed a robust system-dependent dispersion correction, dDsC, that is computed from the electron density and that provides a balanced description of both weak inter- and intramolecular interactions. From the theoretical pointmore » of view and for the sake of increasing reliability, we here verify if the self-consistent implementation of dDsC impacts ground-state properties such as interaction energies, electron density, dipole moments, geometries, and harmonic frequencies. In addition, we investigate the suitability of the a posteriori scheme for molecular dynamics simulations, for which the analysis of the energy conservation constitutes a challenging tests. Our study demonstrates that the post-SCF approach in an excellent approximation.« less

The Acculturation Experiences of Foreign-Born Students of Color in Physics

ERIC Educational Resources Information Center

Fries-Britt, Sharon; George Mwangi, Chrystal A.; Peralta, Alicia M.

2014-01-01

This study focuses on 15 foreign-born students majoring in physics who are also racial/ethnic minorities. We address the research question: What are the acculturation experiences of foreign-born Students of Color majoring in physics? Berry's (2003) theory of acculturation and Bandura's (1994) theory of self-efficacy were substantive…

Twin-singleton differences in intelligence: a register-based birth cohort study of Norwegian males.

PubMed

Eriksen, Willy; Sundet, Jon M; Tambs, Kristian

2012-10-01

The aim was to determine the difference in intelligence between singletons and twins in young adulthood. Data from the Medical Birth Register of Norway were linked with register data from the Norwegian National Conscript Service. The study base consisted of data on the 445,463 males who were born alive in either single or twin births in Norway during 1967-1984 and who were examined at the time of the mandatory military conscription (age 18-20). Within this study base, there were data on 1,653 sibships of full brothers that included at least one man born in single birth and at least one man born in twin birth (4,307 persons, including 2,378 twins and 1,929 singletons). The intelligence scores of the singletons were 11% (95% confidence interval [CI]: 9-14%) of a standard deviation higher than those of the twins, after adjustment for birth year, birth order, parental ages at delivery, parental education levels, and other factors. The adjusted within-family difference was also 11% (95 % CI: 6-16%) of a standard deviation, indicating that unmeasured factors shared by siblings (e.g., maternal body height) have not influenced the estimate in important ways. When gestational age at birth was added to the model, the estimate for the difference in intelligence score was approximately the same. Including birth weight in the model strongly reduced the estimate. In conclusion, twins born in Norway during 1967-1984 had slightly lower intelligence in early adulthood compared with the singletons.

Communication: The description of strong correlation within self-consistent Green's function second-order perturbation theory

NASA Astrophysics Data System (ADS)

Phillips, Jordan J.; Zgid, Dominika

2014-06-01

We report an implementation of self-consistent Green's function many-body theory within a second-order approximation (GF2) for application with molecular systems. This is done by iterative solution of the Dyson equation expressed in matrix form in an atomic orbital basis, where the Green's function and self-energy are built on the imaginary frequency and imaginary time domain, respectively, and fast Fourier transform is used to efficiently transform these quantities as needed. We apply this method to several archetypical examples of strong correlation, such as a H32 finite lattice that displays a highly multireference electronic ground state even at equilibrium lattice spacing. In all cases, GF2 gives a physically meaningful description of the metal to insulator transition in these systems, without resorting to spin-symmetry breaking. Our results show that self-consistent Green's function many-body theory offers a viable route to describing strong correlations while remaining within a computationally tractable single-particle formalism.

Self-consistent theory of atomic Fermi gases with a Feshbach resonance at the superfluid transition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Xiaji; Hu Hui

2005-12-15

A self-consistent theory is derived to describe the BCS-Bose-Einstein-condensate crossover for a strongly interacting Fermi gas with a Feshbach resonance. In the theory the fluctuation of the dressed molecules, consisting of both preformed Cooper pairs and 'bare' Feshbach molecules, has been included within a self-consistent T-matrix approximation, beyond the Nozieres and Schmitt-Rink strategy considered by Ohashi and Griffin. The resulting self-consistent equations are solved numerically to investigate the normal-state properties of the crossover at various resonance widths. It is found that the superfluid transition temperature T{sub c} increases monotonically at all widths as the effective interaction between atoms becomes moremore » attractive. Furthermore, a residue factor Z{sub m} of the molecule's Green function and a complex effective mass have been determined to characterize the fraction and lifetime of Feshbach molecules at T{sub c}. Our many-body calculations of Z{sub m} agree qualitatively well with recent measurments of the gas of {sup 6}Li atoms near the broad resonance at 834 G. The crossover from narrow to broad resonances has also been studied.« less

Comment on “On the quantum theory of molecules” [J. Chem. Phys. 137, 22A544 (2012)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutcliffe, Brian T., E-mail: bsutclif@ulb.ac.be; Woolley, R. Guy

2014-01-21

In our previous paper [B. T. Sutcliffe and R. G. Woolley, J. Chem. Phys. 137, 22A544 (2012)] we argued that the Born-Oppenheimer approximation could not be based on an exact transformation of the molecular Schrödinger equation. In this Comment we suggest that the fundamental reason for the approximate nature of the Born-Oppenheimer model is the lack of a complete set of functions for the electronic space, and the need to describe the continuous spectrum using spectral projection.

Divergence of the total cross section for three body rearrangement collisions with coulomb interactions

NASA Technical Reports Server (NTRS)

Omidvar, K.

1972-01-01

Three charged particles 1, 2, 3 collide according to the reaction 1+(2+3) yields (1+3)+2, where (2+3) and (1+3) are hydrogenlike bound states. It is shown when (1+3) is in a highly excited state n, due to the repulsive potential, the cross section in the first Born approximation behaves as 1/n which makes the total cross section to diverge like ln n. The total cross sections in the higher orders of the Born approximation are similarly divergent logarithmically.

Multi-scale temporal and spatial variation in genotypic composition of Cladophora-borne Escherichia coli populations in Lake Michigan.

PubMed

Badgley, Brian D; Ferguson, John; Vanden Heuvel, Amy; Kleinheinz, Gregory T; McDermott, Colleen M; Sandrin, Todd R; Kinzelman, Julie; Junion, Emily A; Byappanahalli, Muruleedhara N; Whitman, Richard L; Sadowsky, Michael J

2011-01-01

High concentrations of Escherichia coli in mats of Cladophora in the Great Lakes have raised concern over the continued use of this bacterium as an indicator of microbial water quality. Determining the impacts of these environmentally abundant E. coli, however, necessitates a better understanding of their ecology. In this study, the population structure of 4285 Cladophora-borne E. coli isolates, obtained over multiple three day periods from Lake Michigan Cladophora mats in 2007-2009, was examined by using DNA fingerprint analyses. In contrast to previous studies that have been done using isolates from attached Cladophora obtained over large time scales and distances, the extensive sampling done here on free-floating mats over successive days at multiple sites provided a large dataset that allowed for a detailed examination of changes in population structure over a wide range of spatial and temporal scales. While Cladophora-borne E. coli populations were highly diverse and consisted of many unique isolates, multiple clonal groups were also present and accounted for approximately 33% of all isolates examined. Patterns in population structure were also evident. At the broadest scales, E. coli populations showed some temporal clustering when examined by year, but did not show good spatial distinction among sites. E. coli population structure also showed significant patterns at much finer temporal scales. Populations were distinct on an individual mat basis at a given site, and on individual days within a single mat. Results of these studies indicate that Cladophora-borne E. coli populations consist of a mixture of stable, and possibly naturalized, strains that persist during the life of the mat, and more unique, transient strains that can change over rapid time scales. It is clear that further study of microbial processes at fine spatial and temporal scales is needed, and that caution must be taken when interpolating short term microbial dynamics from results obtained from weekly or monthly samples. Copyright © 2010 Elsevier Ltd. All rights reserved.

Multi-scale temporal and spatial variation in genotypic composition of Cladophora-borne Escherichia coli populations in Lake Michigan

USGS Publications Warehouse

Badgley, B.D.; Ferguson, J.; Heuvel, A.V.; Kleinheinz, G.T.; McDermott, C.M.; Sandrin, T.R.; Kinzelman, J.; Junion, E.A.; Byappanahalli, M.N.; Whitman, R.L.; Sadowsky, M.J.

2011-01-01

High concentrations of Escherichia coli in mats of Cladophora in the Great Lakes have raised concern over the continued use of this bacterium as an indicator of microbial water quality. Determining the impacts of these environmentally abundant E. coli, however, necessitates a better understanding of their ecology. In this study, the population structure of 4285 Cladophora-borne E. coli isolates, obtained over multiple three day periods from Lake Michigan Cladophora mats in 2007-2009, was examined by using DNA fingerprint analyses. In contrast to previous studies that have been done using isolates from attached Cladophora obtained over large time scales and distances, the extensive sampling done here on free-floating mats over successive days at multiple sites provided a large dataset that allowed for a detailed examination of changes in population structure over a wide range of spatial and temporal scales. While Cladophora-borne E. coli populations were highly diverse and consisted of many unique isolates, multiple clonal groups were also present and accounted for approximately 33% of all isolates examined. Patterns in population structure were also evident. At the broadest scales, E. coli populations showed some temporal clustering when examined by year, but did not show good spatial distinction among sites. E. coli population structure also showed significant patterns at much finer temporal scales. Populations were distinct on an individual mat basis at a given site, and on individual days within a single mat. Results of these studies indicate that Cladophora-borne E. coli populations consist of a mixture of stable, and possibly naturalized, strains that persist during the life of the mat, and more unique, transient strains that can change over rapid time scales. It is clear that further study of microbial processes at fine spatial and temporal scales is needed, and that caution must be taken when interpolating short term microbial dynamics from results obtained from weekly or monthly samples.

Doubly self-consistent field theory of grafted polymers under simple shear in steady state

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suo, Tongchuan; Whitmore, Mark D., E-mail: mark-whitmore@umanitoba.ca

2014-03-21

We present a generalization of the numerical self-consistent mean-field theory of polymers to the case of grafted polymers under simple shear. The general theoretical framework is presented, and then applied to three different chain models: rods, Gaussian chains, and finitely extensible nonlinear elastic (FENE) chains. The approach is self-consistent at two levels. First, for any flow field, the polymer density profile and effective potential are calculated self-consistently in a manner similar to the usual self-consistent field theory of polymers, except that the calculation is inherently two-dimensional even for a laterally homogeneous system. Second, through the use of a modified Brinkmanmore » equation, the flow field and the polymer profile are made self-consistent with respect to each other. For all chain models, we find that reasonable levels of shear cause the chains to tilt, but it has very little effect on the overall thickness of the polymer layer, causing a small decrease for rods, and an increase of no more than a few percent for the Gaussian and FENE chains. Using the FENE model, we also probe the individual bond lengths, bond correlations, and bond angles along the chains, the effects of the shear on them, and the solvent and bonded stress profiles. We find that the approximations needed within the theory for the Brinkman equation affect the bonded stress, but none of the other quantities.« less

Understanding differences in access and use of healthcare between international immigrants to Chile and the Chilean-born: a repeated cross-sectional population-based study in Chile.

PubMed

Cabieses, Baltica; Tunstall, Helena; Pickett, Kate E; Gideon, Jasmine

2012-11-16

International evidence indicates consistently lower rates of access and use of healthcare by international immigrants. Factors associated with this phenomenon vary significantly depending on the context. Some research into the health of immigrants has been conducted in Latin America, mostly from a qualitative perspective. This population-based study is the first quantitative study to explore healthcare provision entitlement and use of healthcare services by immigrants in Chile and compare them to the Chilean-born. Data come from the nationally representative CASEN (Socioeconomic characterization of the population in Chile) surveys, conducted in 2006 and 2009. Self-reported immigrants were compared to the Chilean-born, by demographic characteristics (age, sex, urban/rural, household composition, ethnicity), socioeconomic status (SES: education, household income, contractual status), healthcare provision entitlement (public, private, other, none), and use of primary services. Weighted descriptive, stratified and adjusted regression models were used to analyse factors associated with access to and use of healthcare. There was an increase in self-reported immigrant status and in household income inequality among immigrants between 2006 and 2009. Over time there was a decrease in the rate of immigrants reporting no healthcare provision and an increase in reporting of private healthcare provision entitlement. Compared to the Chilean-born, immigrants reported higher rates of use of antenatal and gynaecological care, lower use of well-baby care, and no difference in the use of Pap smears or the number of attentions received in the last three months. Immigrants in the bottom income quintile were four times more likely to report no healthcare provision than their equivalent Chilean-born group (with different health needs, i.e. vertical inequity). Disabled immigrants were more likely to have no healthcare provision compared to the disabled Chilean-born (with similar health needs, i.e. horizontal inequity). Factors associated with immigrants' access to, and use of, healthcare were sex, urban/rural status, education and country of origin. There were significant associations between SES, and access to and use of healthcare among immigrants in Chile and a higher prevalence of no health care provision entitlement among poor and disabled immigrants compared to the Chilean-born. Changing associations between access and use of healthcare and SES among immigrants in Chile over time may reflect changes in their socio-demographic composition or in the survey methodology between 2006 and 2009.

Born Hartree Bethe approximation in the theory of inelastic electron molecule scattering

NASA Astrophysics Data System (ADS)

Kretinin, I. Yu; Krisilov, A. V.; Zon, B. A.

2008-11-01

We propose a new approximation in the theory of inelastic electron atom and electron molecule scattering. Taking into account the completeness property of atomic and molecular wavefunctions, considered in the Hartree approximation, and using Bethe's parametrization for electronic excitations during inelastic collisions via the mean excitation energy, we show that the calculation of the inelastic total integral cross-sections (TICS), in the framework of the first Born approximation, involves only the ground-state wavefunction. The final analytical formula obtained for the TICS, i.e. for the sum of elastic and inelastic ones, contains no adjusting parameters. Calculated TICS for electron scattering by light atoms and molecules (He, Ne, and H2) are in good agreement within the experimental data; results show asymptotic coincidence for heavier ones (Ar, Kr, Xe and N2).

Age at migration and self-rated health trajectories after age 50: understanding the older immigrant health paradox.

PubMed

Gubernskaya, Zoya

2015-03-01

This research contributes to the "immigrant health paradox" debate by testing the hypothesis that older age at migration is associated with the increased risk of poor health in later life. Using the 1992-2008 Health and Retirement Study, I construct linear random-intercept models to estimate self-rated health (SRH) trajectories after age 50 for the native and foreign born by age at migration. At age 50, both Hispanic and non-Hispanic foreign born report better SRH compared with their native-born counterparts, net of race, gender, and education. Non-Hispanic foreign born who migrated after age 35 and Hispanic foreign born who migrated after age 18, however, experience steeper decline in SRH after age 50, which results in a health disadvantage vis-à-vis the native born in old age. Education has a smaller protective effect on SRH for the foreign born, especially those who migrated as adults. Age at migration is an important factor for understanding health status of older immigrants. Steeper health decline in later life of the foreign born who migrated in advanced ages may be related to longer exposure to unfavorable conditions in home countries and limited opportunities for incorporation in the United States. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Tracer Lamination in the Stratosphere: A Global Climatology

NASA Technical Reports Server (NTRS)

Appenzeller, Christof; Holton, James R.

1997-01-01

Vertical soundings of stratospheric ozone often exhibit laminated tracer structures characterized by strong vertical tracer gradients. The change in time of these gradients is used to define a tracer lamination rate. It is shown that this quantity can be calculated by the cross product of the horizontal temperature and horizontal tracer gradients. A climatology based on UARS satellite-borne ozone data and on ozone-like pseudotracer data is presented. Three stratospheric regions with high lamination rates were found: the part of the stratospheric overworld which is influenced by the polar vortex, the part of the lowermost stratosphere which is influenced by the tropopause and a third region in the subtropical lower stratosphere mainly characterized with strong vertical shear. High lamination rates in the stratospheric overworld were absent during summer, whereas in the lowermost stratosphere high lamination rates were found year-round. This is consistent with the occurrence and seasonal variation of the horizontal tracer gradient and vertical shear necessary for tilting the tracer surfaces. During winter, high lamination rates associated with the stratospheric polar vortex are present down to approximately 100 hPa. Several features of the derived climatology are roughly consistent with earlier balloon-borne studies. The patterns in the southern and northern hemisphere are comparable, but details differ as anticipated from a less disturbed and more symmetric southern polar vortex.

Association between Birth Order and Emergency Room Visits and Acute Hospital Admissions following Pediatric Vaccination: A Self-Controlled Study

PubMed Central

Hawken, Steven; Kwong, Jeffrey C.; Deeks, Shelley L.; Crowcroft, Natasha S.; Ducharme, Robin; Manuel, Douglas G.; Wilson, Kumanan

2013-01-01

Objective We investigated the association between a child's birth order and emergency room (ER) visits and hospital admissions following 2-,4-,6- and 12-month pediatric vaccinations. Methods We included all children born in Ontario between April 1st, 2006 and March 31st, 2009 who received a qualifying vaccination. We identified vaccinations, ER visits and admissions using health administrative data housed at the Institute for Clinical Evaluative Sciences. We used the self-controlled case series design to compare the relative incidence (RI) of events among 1st-born and later-born children using relative incidence ratios (RIR). Results For the 2-month vaccination, the RIR for 1st-borns versus later-born children was 1.37 (95% CI: 1.19–1.57), which translates to 112 additional events/100,000 vaccinated. For the 4-month vaccination, the RIR for 1st-borns vs. later-borns was 1.70 (95% CI: 1.45–1.99), representing 157 additional events/100,000 vaccinated. At 6 months, the RIR for 1st vs. later-borns was 1.27 (95% CI: 1.09–1.48), or 77 excess events/100,000 vaccinated. At the 12-month vaccination, the RIR was 1.11 (95% CI: 1.02–1.21), or 249 excess events/100,000 vaccinated. Conclusions Birth order is associated with increased incidence of ER visits and hospitalizations following vaccination in infancy. 1st-born children had significantly higher relative incidence of events compared to later-born children. PMID:24324662

Origin of non-spherical particles in the boundary layer over Beijing, China: based on balloon-borne observations.

PubMed

Chen, Bin; Yamada, Maromu; Iwasaka, Yasunobu; Zhang, Daizhou; Wang, Hong; Wang, Zhenzhu; Lei, Hengchi; Shi, Guangyu

2015-10-01

Vertical structures of aerosols from the ground to about 1,000 m altitude in Beijing were measured with a balloon-borne optical particle counter. The results showed that, in hazy days, there were inversions at approximately 500-600 m, below which the particulate matters were well mixed vertically, while the concentration of particles decreased sharply above the mixing layer. Electron microscopic observation of the particles collected with the balloon-borne impactor indicates that the composition of particles is different according to weather conditions in the boundary mixing layer of Beijing city and suggests that dust particles are always dominant in coarse-mode particles. Interestingly, sea-salt particles are frequently identified, suggesting the importance of marine air inflow to the Beijing area even in summer. The Ca-rich spherical particles are also frequently identified, suggesting chemical modification of dust particle by NOx or emission of CaO and others from local emission. Additionally, those types of particles showed higher concentration above the mixing layer under the relatively calm weather condition of summer, suggesting the importance of local-scale convection found in summer which rapidly transported anthropogenic particles above the mixing layer. Lidar extinction profiles qualitatively have good consistency with the balloon-borne measurements. Attenuation effects of laser pulse intensity are frequently observed due to high concentration of particulate matter in the Beijing atmosphere, and therefore quantitative agreement of lidar return and aerosol concentration can be hardly observed during dusty condition. Comparing the depolarization ratio obtained from the lidar measurements with the balloon-borne measurements, the contribution of the dry sea-salt particles, in addition to the dust particles, is suggested as an important factor causing depolarization ratio in the Beijing atmosphere.

Imaging electrical conductivity, permeability, and/or permittivity contrasts using the Born Scattering Inversion (BSI)

NASA Astrophysics Data System (ADS)

Darrh, A.; Downs, C. M.; Poppeliers, C.

2017-12-01

Born Scattering Inversion (BSI) of electromagnetic (EM) data is a geophysical imaging methodology for mapping weak conductivity, permeability, and/or permittivity contrasts in the subsurface. The high computational cost of full waveform inversion is reduced by adopting the First Born Approximation for scattered EM fields. This linearizes the inverse problem in terms of Born scattering amplitudes for a set of effective EM body sources within a 3D imaging volume. Estimation of scatterer amplitudes is subsequently achieved by solving the normal equations. Our present BSI numerical experiments entail Fourier transforming real-valued synthetic EM data to the frequency-domain, and minimizing the L2 residual between complex-valued observed and predicted data. We are testing the ability of BSI to resolve simple scattering models. For our initial experiments, synthetic data are acquired by three-component (3C) electric field receivers distributed on a plane above a single point electric dipole within a homogeneous and isotropic wholespace. To suppress artifacts, candidate Born scatterer locations are confined to a volume beneath the receiver array. Also, we explore two different numerical linear algebra algorithms for solving the normal equations: Damped Least Squares (DLS), and Non-Negative Least Squares (NNLS). Results from NNLS accurately recover the source location only for a large dense 3C receiver array, but fail when the array is decimated, or is restricted to horizontal component data. Using all receiver stations and all components per station, NNLS results are relatively insensitive to a sub-sampled frequency spectrum, suggesting that coarse frequency-domain sampling may be adequate for good target resolution. Results from DLS are insensitive to diminishing array density, but contain spatially oscillatory structure. DLS-generated images are consistently centered at the known point source location, despite an abundance of surrounding structure.

Transport across nanogaps using self-consistent boundary conditions

NASA Astrophysics Data System (ADS)

Biswas, D.; Kumar, R.

2012-06-01

Charge particle transport across nanogaps is studied theoretically within the Schrodinger-Poisson mean field framework. The determination of self-consistent boundary conditions across the gap forms the central theme in order to allow for realistic interface potentials (such as metal-vacuum) which are smooth at the boundary and do not abruptly assume a constant value at the interface. It is shown that a semiclassical expansion of the transmitted wavefunction leads to approximate but self consistent boundary conditions without assuming any specific form of the potential beyond the gap. Neglecting the exchange and correlation potentials, the quantum Child-Langmuir law is investigated. It is shown that at zero injection energy, the quantum limiting current density (Jc) is found to obey the local scaling law Jc ~ Vgα/D5-2α with the gap separation D and voltage Vg. The exponent α > 1.1 with α → 3/2 in the classical regime of small de Broglie wavelengths.

Communication: A difference density picture for the self-consistent field ansatz.

PubMed

Parrish, Robert M; Liu, Fang; Martínez, Todd J

2016-04-07

We formulate self-consistent field (SCF) theory in terms of an interaction picture where the working variable is the difference density matrix between the true system and a corresponding superposition of atomic densities. As the difference density matrix directly represents the electronic deformations inherent in chemical bonding, this "difference self-consistent field (dSCF)" picture provides a number of significant conceptual and computational advantages. We show that this allows for a stable and efficient dSCF iterative procedure with wholly single-precision Coulomb and exchange matrix builds. We also show that the dSCF iterative procedure can be performed with aggressive screening of the pair space. These approximations are tested and found to be accurate for systems with up to 1860 atoms and >10 000 basis functions, providing for immediate overall speedups of up to 70% in the heavily optimized TeraChem SCF implementation.

Communication: A difference density picture for the self-consistent field ansatz

NASA Astrophysics Data System (ADS)

Parrish, Robert M.; Liu, Fang; Martínez, Todd J.

2016-04-01

We formulate self-consistent field (SCF) theory in terms of an interaction picture where the working variable is the difference density matrix between the true system and a corresponding superposition of atomic densities. As the difference density matrix directly represents the electronic deformations inherent in chemical bonding, this "difference self-consistent field (dSCF)" picture provides a number of significant conceptual and computational advantages. We show that this allows for a stable and efficient dSCF iterative procedure with wholly single-precision Coulomb and exchange matrix builds. We also show that the dSCF iterative procedure can be performed with aggressive screening of the pair space. These approximations are tested and found to be accurate for systems with up to 1860 atoms and >10 000 basis functions, providing for immediate overall speedups of up to 70% in the heavily optimized TeraChem SCF implementation.

Approximation for discrete Fourier transform and application in study of three-dimensional interacting electron gas.

PubMed

Yan, Xin-Zhong

2011-07-01

The discrete Fourier transform is approximated by summing over part of the terms with corresponding weights. The approximation reduces significantly the requirement for computer memory storage and enhances the numerical computation efficiency with several orders without losing accuracy. As an example, we apply the algorithm to study the three-dimensional interacting electron gas under the renormalized-ring-diagram approximation where the Green's function needs to be self-consistently solved. We present the results for the chemical potential, compressibility, free energy, entropy, and specific heat of the system. The ground-state energy obtained by the present calculation is compared with the existing results of Monte Carlo simulation and random-phase approximation.

Resonating group method as applied to the spectroscopy of α-transfer reactions

NASA Astrophysics Data System (ADS)

Subbotin, V. B.; Semjonov, V. M.; Gridnev, K. A.; Hefter, E. F.

1983-10-01

In the conventional approach to α-transfer reactions the finite- and/or zero-range distorted-wave Born approximation is used in liaison with a macroscopic description of the captured α particle in the residual nucleus. Here the specific example of 16O(6Li,d)20Ne reactions at different projectile energies is taken to present a microscopic resonating group method analysis of the α particle in the final nucleus (for the reaction part the simple zero-range distorted-wave Born approximation is employed). In the discussion of suitable nucleon-nucleon interactions, force number one of the effective interactions presented by Volkov is shown to be most appropriate for the system considered. Application of the continuous analog of Newton's method to the evaluation of the resonating group method equations yields an increased accuracy with respect to traditional methods. The resonating group method description induces only minor changes in the structures of the angular distributions, but it does serve its purpose in yielding reliable and consistent spectroscopic information. NUCLEAR STRUCTURE 16O(6Li,d)20Ne; E=20 to 32 MeV; calculated B(E2); reduced widths, dσdΩ extracted α-spectroscopic factors. ZRDWBA with microscope RGM description of residual α particle in 20Ne; application of continuous analog of Newton's method; tested and applied Volkov force No. 1; direct mechanism.

Excitation spectra of aromatic molecules within a real-space G W -BSE formalism: Role of self-consistency and vertex corrections

DOE PAGES

Hung, Linda; da Jornada, Felipe H.; Souto-Casares, Jaime; ...

2016-08-15

Here, we present first-principles calculations on the vertical ionization potentials (IPs), electron affinities (EAs), and singlet excitation energies on an aromatic-molecule test set (benzene, thiophene, 1,2,5-thiadiazole, naphthalene, benzothiazole, and tetrathiafulvalene) within the GW and Bethe-Salpeter equation (BSE) formalisms. Our computational framework, which employs a real-space basis for ground-state and a transition-space basis for excited-state calculations, is well suited for high-accuracy calculations on molecules, as we show by comparing against G0W0 calculations within a plane-wave-basis formalism. We then generalize our framework to test variants of the GW approximation that include a local density approximation (LDA)–derived vertex function (Γ LDA ) andmore » quasiparticle-self-consistent (QS) iterations. We find that Γ LDA and quasiparticle self-consistency shift IPs and EAs by roughly the same magnitude, but with opposite sign for IPs and the same sign for EAs. G0W0 and QS GWΓ LDA are more accurate for IPs, while G 0W 0Γ LDA and QS GW are best for EAs. For optical excitations, we find that perturbative GW-BSE underestimates the singlet excitation energy, while self-consistent GW-BSE results in good agreement with previous best-estimate values for both valence and Rydberg excitations. Finally, our work suggests that a hybrid approach, in which G0W0 energies are used for occupied orbitals and G0W0Γ LDA for unoccupied orbitals, also yields optical excitation energies in good agreement with experiment but at a smaller computational cost.« less

Excitation spectra of aromatic molecules within a real-space G W -BSE formalism: Role of self-consistency and vertex corrections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hung, Linda; da Jornada, Felipe H.; Souto-Casares, Jaime

Here, we present first-principles calculations on the vertical ionization potentials (IPs), electron affinities (EAs), and singlet excitation energies on an aromatic-molecule test set (benzene, thiophene, 1,2,5-thiadiazole, naphthalene, benzothiazole, and tetrathiafulvalene) within the GW and Bethe-Salpeter equation (BSE) formalisms. Our computational framework, which employs a real-space basis for ground-state and a transition-space basis for excited-state calculations, is well suited for high-accuracy calculations on molecules, as we show by comparing against G0W0 calculations within a plane-wave-basis formalism. We then generalize our framework to test variants of the GW approximation that include a local density approximation (LDA)–derived vertex function (Γ LDA ) andmore » quasiparticle-self-consistent (QS) iterations. We find that Γ LDA and quasiparticle self-consistency shift IPs and EAs by roughly the same magnitude, but with opposite sign for IPs and the same sign for EAs. G0W0 and QS GWΓ LDA are more accurate for IPs, while G 0W 0Γ LDA and QS GW are best for EAs. For optical excitations, we find that perturbative GW-BSE underestimates the singlet excitation energy, while self-consistent GW-BSE results in good agreement with previous best-estimate values for both valence and Rydberg excitations. Finally, our work suggests that a hybrid approach, in which G0W0 energies are used for occupied orbitals and G0W0Γ LDA for unoccupied orbitals, also yields optical excitation energies in good agreement with experiment but at a smaller computational cost.« less

Aging in Australia: country of birth and language preferences of residents in aged care facilities.

PubMed

Petrov, Ljubica; Joyce, Catherine; Gucciardo-Masci, Tonina

2017-09-05

Objective There is a need to better understand the use of aged care services by people from culturally and linguistically diverse backgrounds. The aim of the present study was to describe the prevalence of people living in residential aged care facilities (RACFs) who were born in non-English-speaking countries and/or have a preferred language other than English and to describe service utilisation rates. Methods The present study consisted of a secondary analysis of data from the Australian Institute of Health and Welfare National Aged Care Data Clearinghouse. Data were analysed by country of birth, preferred language, state or territory and Aged Care Planning Regions within Victoria. Results Nationally, over 30000 (18.3%) RACF residents were born in a non-English-speaking country. In Victoria, almost one in four RACF residents (23.9%) was born in a non-English-speaking country, and approximately one in eight (13.1%) has a preferred language other than English. Most Victorian RACFs (72.4%) have at least one resident with a preferred language other than English. Approximately one in four residents (26.1%) with a preferred language other than English are the sole speaker of the language in their facility. Conclusion All RACFs need to effectively address the needs and preferences of their residents, including those who were born in a non-English-speaking country or prefer to speak a language other than English. What is known about the topic? The number of older people from a non-English-speaking background continues to increase, but little is known about the prevalence of this cohort living in RACFs and how aged care providers are responding to their needs and preferences. What does this paper add? The present study provides detailed, service- and policy-relevant information, demonstrating a substantial degree of diversity among people living in RACFs, with wide distribution across facilities and regions. The findings confirm the need for a systematic, sector-wide approach to addressing linguistic diversity and developing inclusive practices. What are the implications for practitioners? All RACFs are required to develop policies and procedures in order to cater to the needs and preferences of residents who were born in non-English-speaking countries and/or who prefer to speak a language other than English.

Postresuscitation Care and Pretransport Stabilization of Newborns Using the Principles of STABLE Transport.

PubMed

Bellini, Sandra

The practice of perinatal regionalization is designed to ensure that newborns are born in facilities with a care level designation that is consistent with expected pregnancy outcomes. Regionalization practices have resulted in lower neonatal mortality and morbidity rates. However, despite regionalization efforts, approximately 10 percent of newborns will require some level assistance with breathing, and a few (<1 percent) will require resuscitation in the birthing room. After resuscitation, many of these newborns require acute transport to a different facility. This column provides an overview of principles from the STABLE Program, which guides clinicians in providing postresuscitation care and pretransport stabilization for compromised newborns. © 2015 AWHONN.

Domestic violence and immigration status among Latina mothers in the child welfare system: findings from the National Survey of Child and Adolescent Well-being II (NSCAW II).

PubMed

Ogbonnaya, Ijeoma Nwabuzor; Finno-Velasquez, Megan; Kohl, Patricia L

2015-01-01

Many children involved with the child welfare system witness parental domestic violence. The association between children's domestic violence exposure and child welfare involvement may be influenced by certain socio-cultural factors; however, minimal research has examined this relationship. The current study compares domestic violence experiences and case outcomes among Latinas who are legal immigrants (n=39), unauthorized immigrants (n=77), naturalized citizens (n=30), and US-born citizen mothers (n=383) reported for child maltreatment. This analysis used data from the second round of the National Survey of Child and Adolescent Well-being. Mothers were asked about whether they experienced domestic violence during the past year. In addition, data were collected to assess if (a) domestic violence was the primary abuse type reported and, if so, (b) the maltreatment allegation was substantiated. Results show that naturalized citizens, legal residents, and unauthorized immigrants did not differ from US-born citizens in self-reports of domestic violence; approximately 33% of mothers reported experiences of domestic violence within the past year. Yet, unauthorized immigrants were 3.76 times more likely than US-born citizens to have cases with allegations of domestic violence as the primary abuse type. Despite higher rates of alleged domestic violence, unauthorized citizens were not more likely than US-born citizens to have these cases substantiated for domestic violence (F(2.26, 153.99)=0.709, p=.510). Findings highlight that domestic violence is not accurately accounted for in families with unauthorized immigrant mothers. We recommend child welfare workers are trained to properly assess and fulfill the needs of immigrant families, particularly as it relates to domestic violence. Copyright © 2014 Elsevier Ltd. All rights reserved.

Theoretical L-shell Coster-Kronig energies 11 or equal to z or equal to 103

NASA Technical Reports Server (NTRS)

Chen, M. H.; Crasemann, B.; Huang, K. N.; Aoyagi, M.; Mark, H.

1976-01-01

Relativistic relaxed-orbital calculations of L-shell Coster-Kronig transition energies have been performed for all possible transitions in atoms with atomic numbers. Hartree-Fock-Slater wave functions served as zeroth-order eigenfunctions to compute the expectation of the total Hamiltonian. A first-order approximation to the local approximation was thus included. Quantum-electrodynamic corrections were made. Each transition energy was computed as the difference between results of separate self-consistent-field calculations for the initial, singly ionized state and the final two-hole state. The following quantities are listed: total transition energy, 'electric' (Dirac-Hartree-Fock-Slater) contribution, magnetic and retardation contributions, and contributions due to vacuum polarization and self energy.

Two-dimensional self-organization of an ordered Au silicide nanowire network on a Si(110)-16 x 2 surface.

PubMed

Hong, Ie-Hong; Yen, Shang-Chieh; Lin, Fu-Shiang

2009-08-17

A well-ordered two-dimensional (2D) network consisting of two crossed Au silicide nanowire (NW) arrays is self-organized on a Si(110)-16 x 2 surface by the direct-current heating of approximately 1.5 monolayers of Au on the surface at 1100 K. Such a highly regular crossbar nanomesh exhibits both a perfect long-range spatial order and a high integration density over a mesoscopic area, and these two self-ordering crossed arrays of parallel-aligned NWs have distinctly different sizes and conductivities. NWs are fabricated with widths and pitches as small as approximately 2 and approximately 5 nm, respectively. The difference in the conductivities of two crossed-NW arrays opens up the possibility for their utilization in nanodevices of crossbar architecture. Scanning tunneling microscopy/spectroscopy studies show that the 2D self-organization of this perfect Au silicide nanomesh can be achieved through two different directional electromigrations of Au silicide NWs along different orientations of two nonorthogonal 16 x 2 domains, which are driven by the electrical field of direct-current heating. Prospects for this Au silicide nanomesh are also discussed.

keV-Scale sterile neutrino sensitivity estimation with time-of-flight spectroscopy in KATRIN using self-consistent approximate Monte Carlo

NASA Astrophysics Data System (ADS)

Steinbrink, Nicholas M. N.; Behrens, Jan D.; Mertens, Susanne; Ranitzsch, Philipp C.-O.; Weinheimer, Christian

2018-03-01

We investigate the sensitivity of the Karlsruhe Tritium Neutrino Experiment (KATRIN) to keV-scale sterile neutrinos, which are promising dark matter candidates. Since the active-sterile mixing would lead to a second component in the tritium β-spectrum with a weak relative intensity of order sin ^2θ ≲ 10^{-6}, additional experimental strategies are required to extract this small signature and to eliminate systematics. A possible strategy is to run the experiment in an alternative time-of-flight (TOF) mode, yielding differential TOF spectra in contrast to the integrating standard mode. In order to estimate the sensitivity from a reduced sample size, a new analysis method, called self-consistent approximate Monte Carlo (SCAMC), has been developed. The simulations show that an ideal TOF mode would be able to achieve a statistical sensitivity of sin ^2θ ˜ 5 × 10^{-9} at one σ , improving the standard mode by approximately a factor two. This relative benefit grows significantly if additional exemplary systematics are considered. A possible implementation of the TOF mode with existing hardware, called gated filtering, is investigated, which, however, comes at the price of a reduced average signal rate.

Recurrent evolution of host and vector association in bacteria of the Borrelia burgdorferi sensu lato species complex.

PubMed

Becker, Noémie S; Margos, Gabriele; Blum, Helmut; Krebs, Stefan; Graf, Alexander; Lane, Robert S; Castillo-Ramírez, Santiago; Sing, Andreas; Fingerle, Volker

2016-09-15

The Borrelia burgdorferi sensu lato (s.l.) species complex consists of tick-transmitted bacteria and currently comprises approximately 20 named and proposed genospecies some of which are known to cause Lyme Borreliosis. Species have been defined via genetic distances and ecological niches they occupy. Understanding the evolutionary relationship of species of the complex is fundamental to explaining patterns of speciation. This in turn forms a crucial basis to frame testable hypotheses concerning the underlying processes including host and vector adaptations. Illumina Technology was used to obtain genome-wide sequence data for 93 strains of 14 named genospecies of the B. burgdorferi species complex and genomic data already published for 18 additional strain (including one new species) was added. Phylogenetic reconstruction based on 114 orthologous single copy genes shows that the genospecies represent clearly distinguishable taxa with recent and still ongoing speciation events apparent in Europe and Asia. The position of Borrelia species in the phylogeny is consistent with host associations constituting a major driver for speciation. Interestingly, the data also demonstrate that vector associations are an additional driver for diversification in this tick-borne species complex. This is particularly obvious in B. bavariensis, a rodent adapted species that has diverged from the bird-associated B. garinii most likely in Asia. It now consists of two populations one of which most probably invaded Europe following adaptation to a new vector (Ixodes ricinus) and currently expands its distribution range. The results imply that genotypes/species with novel properties regarding host or vector associations have evolved recurrently during the history of the species complex and may emerge at any time. We suggest that the finding of vector associations as a driver for diversification may be a general pattern for tick-borne pathogens. The core genome analysis presented here provides an important source for investigations of the underlying mechanisms of speciation in tick-borne pathogens.

The Development of Ethnic/Racial Self-Labeling: Individual Differences in Context.

PubMed

Cheon, Yuen Mi; Bayless, Sara Douglass; Wang, Yijie; Yip, Tiffany

2018-03-15

Ethnic/racial self-labeling represents one's knowledge of and preference for ethnic/racial group membership, which is related to, but distinguishable from, ethnic/racial identity. This study examined the development of ethnic/racial self-labeling over time by including the concept of elaboration among a diverse sample of 297 adolescents (Time 1 mean age 14.75, 67% female, 37.4% Asian or Asian American, 10.4% Black, African American, or West Indian, 23.2% Hispanic or Latinx, 24.2% White, 4.4% other). Growth mixture modeling revealed two distinct patterns-low and high self-labeling elaboration from freshman to sophomore year of high school. Based on logistic regression analyses, the level of self-labeling elaboration was generally low among the adolescents who were foreign-born, reported low levels of ethnic/racial identity exploration, or attended highly diverse schools. We also found a person-by-context interaction where the impact of school diversity varied for foreign-born and native-born adolescents (b = 12.81, SE = 6.30, p < 0.05) and by the level of ethnic/racial identity commitment (b = 14.32, SE = 6.65, p < 0.05). These findings suggest varying patterns in ethnic/racial self-labeling elaboration among adolescents from diverse backgrounds and their linkage to individual and contextual factors.

Birth order and self-concept in adolescence.

PubMed

Gecas, V; Pasley, K

1983-12-01

The effect of birth order on self-concept was examined in a sample of adolescent boys and girls. Based upon self-theory, which suggests that the two main processes of self-concept formation (e.g., reflected appraisals and social comparisons) are affected by the power and role relationships associated with ordinal position in the family, several hypotheses were tested: (1) The self-evaluations of only and oldest children are more positive than those of younger siblings; (2) middle-borns have the lowest self-evaluations; (3) these relationships are affected by the sex and spacing of nearest sibling; and (4) the self-conceptions of oldest and only children are more similar to those of their parents than the self-conceptions of younger siblings and their parents. Using analysis of variance and several different measures of self-evaluation, very little support was found for any of these hypotheses. The strongest support was found for the hypothesis on middle-borns, but even these relationships were not large. Several explanations are offered for these weak and inconsistent findings.

Structure of physical crystalline membranes within the self-consistent screening approximation.

PubMed

Gazit, Doron

2009-10-01

The anomalous exponents governing the long-wavelength behavior of the flat phase of physical crystalline membranes are calculated within a self-consistent screening approximation (SCSA) applied to second order expansion in 1/dC ( dC is the codimension), extending the seminal work of Le Doussal and Radzihovsky [Phys. Rev. Lett. 69, 1209 (1992)]. In particular, the bending rigidity is found to harden algebraically in the long-wavelength limit with an exponent eta=0.789... , which is used to extract the elasticity softening exponent eta(u)=0.422... , and the roughness exponent zeta=0.605... . The scaling relation eta(u)=2-2eta is proven to hold to all orders in SCSA. Further, applying the SCSA to an expansion in 1/dC , is found to be essential, as no solution to the self-consistent equations is found in a two-bubble level, which is the naive second-order expansion. Surprisingly, even though the expansion parameter for physical membrane is 1/dC=1 , the SCSA applied to second-order expansion deviates only slightly from the first order, increasing zeta by mere 0.016. This supports the high quality of the SCSA for physical crystalline membranes, as well as improves the comparison to experiments and numerical simulations of these systems. The prediction of SCSA applied to first order expansion for the Poisson ratio is shown to be exact to all orders.

Self-organization, the cascade model, and natural hazards.

PubMed

Turcotte, Donald L; Malamud, Bruce D; Guzzetti, Fausto; Reichenbach, Paola

2002-02-19

We consider the frequency-size statistics of two natural hazards, forest fires and landslides. Both appear to satisfy power-law (fractal) distributions to a good approximation under a wide variety of conditions. Two simple cellular-automata models have been proposed as analogs for this observed behavior, the forest fire model for forest fires and the sand pile model for landslides. The behavior of these models can be understood in terms of a self-similar inverse cascade. For the forest fire model the cascade consists of the coalescence of clusters of trees; for the sand pile model the cascade consists of the coalescence of metastable regions.

An SCF and MCSCF description of the low-lying states of MgO. [Configuration State Functions Multiconfiguration Self Consistent Field

NASA Technical Reports Server (NTRS)

Bauschlicher, C. W., Jr.; Silver, D. M.; Yarkony, D. R.

1980-01-01

The paper presents the multiconfiguration-self-consistent (MCSCF) and configuration state functions (CSF) for the low-lying electronic states of MgO. It was shown that simple description of these states was possible provided the 1 Sigma(+) states are individually optimized at the MCSCF level, noting that the 1(3 Sigma)(+) and 2(1 Sigma)(+) states which nominally result from the same electron occupation are separated energetically. The molecular orbitals obtained at this level of approximation should provide a useful starting point for extended configuration interaction calculations since they have been optimized for the particular states of interest.

Self-organization, the cascade model, and natural hazards

PubMed Central

Turcotte, Donald L.; Malamud, Bruce D.; Guzzetti, Fausto; Reichenbach, Paola

2002-01-01

We consider the frequency-size statistics of two natural hazards, forest fires and landslides. Both appear to satisfy power-law (fractal) distributions to a good approximation under a wide variety of conditions. Two simple cellular-automata models have been proposed as analogs for this observed behavior, the forest fire model for forest fires and the sand pile model for landslides. The behavior of these models can be understood in terms of a self-similar inverse cascade. For the forest fire model the cascade consists of the coalescence of clusters of trees; for the sand pile model the cascade consists of the coalescence of metastable regions. PMID:11875206

Self-lubricating layer consist of polytetrafluoroethylene micropowders and fluorocarbon acrylate resin formation on surface of geotextile

NASA Astrophysics Data System (ADS)

Long, Xiaoyun; He, Lifen; Zhang, Yan; Ge, Mingqiao

2018-04-01

In this study, the self-lubricating layer consist of polytetrafluoroethylene (PTFE) micropowders and two types fluorocarbon acrylate resin were formed on the surface of geotextile, to improves the evenness and decreases the frictional angle value of geotextile surface. The surface and cross section morphology of geotextile were examined by scanning electron microscopy (SEM). It was determined that composite resin emulsion was evenly coated on the surface of geotextile, to form a even and complete self-lubricating layer, and it was strongly combined with the geotextile due to formation of the transition layer. The tensile fracture stress and strain values of samples were evaluated by mechanical properties measurement, the tensile fracture stress of the untreated and treated sample was approximately 5329 kN/m and 5452 kN/m while the elongation at the yield of them was approximately 85% to 83.9%, respectively. In addition, the frictional angle values of municipal solid waste (MSW)/geotextile interface was measured by the tilt table test, the values of untreated sample was 28.1° and 24.2° under the dry and moist condition, the values of treated sample was 16.2° and 9.8°, respectively.

Determination of the charge of relativistic heavy nuclei from emulsion tracks

NASA Technical Reports Server (NTRS)

Morgan, S. H., Jr.; Eby, P. B.

1971-01-01

The number of delta rays with energies between 50 and 150 keV that are produced by heavy nuclei in emulsions is calculated. The Z(2) dependence predicted by the first Born approximation is corrected by a direct calculation of the Mott exact phase-shift scattering cross section. Comparisons are made with corrections predicted by the second Born approximation. When the phase-shift results are applied to the problem of charge identification, corrections of up to 4 units of charge for 1.457-GeV/nucleon nuclei with charge Z = 75 are found.

Measurements of the scattering of sound by a line vortex

NASA Technical Reports Server (NTRS)

Horne, W. C.

1983-01-01

This paper presents measurements of the phase and magnitude of the scattered field arising from the incidence of a monochromatic plane sound field as a steady vortex. The amplitude of the scattered field was found to vary linearly with the vortex strength, and with the incident wave amplitude and frequency as predicted by solutions based on the Born approximation. The scattered field was observed to be nonsingular in the incidence direction, and this was similar to predictions by the Parabolic Equation Method (PEM) rather than the Born approximation, which predicts singular behavior in the incidence direction.

Initial results from the Caltech/DSRI balloon-borne isotope experiment

NASA Technical Reports Server (NTRS)

Schindler, S. M.; Buffington, A.; Christian, E. C.; Grove, J. E.; Lau, K. H.; Stone, E. C.; Rasmussen, I. L.; Laursen, S.

1985-01-01

The Caltech/DSRI balloon-borne High Energy Isotope Spectrometer Telescope (HEIST) was flown successfully from Palestine, Texas on 14 May 1984. The experiment was designed to measure cosmic ray isotopic abundances from neon through iron, with incident particle energies from approximately 1.5 to 2.2 GeV/nucleon, depending on the element. During approximately 38 hours at float altitude, 10 to the 5th events were recorded with Z or = 6 and incident energies 1.5 GeV/nucleon. We present results from the ongoing data analysis associated with both the pre-flight Bevalac calibration and the flight data.

Self-consistent field model for strong electrostatic correlations and inhomogeneous dielectric media.

PubMed

Ma, Manman; Xu, Zhenli

2014-12-28

Electrostatic correlations and variable permittivity of electrolytes are essential for exploring many chemical and physical properties of interfaces in aqueous solutions. We propose a continuum electrostatic model for the treatment of these effects in the framework of the self-consistent field theory. The model incorporates a space- or field-dependent dielectric permittivity and an excluded ion-size effect for the correlation energy. This results in a self-energy modified Poisson-Nernst-Planck or Poisson-Boltzmann equation together with state equations for the self energy and the dielectric function. We show that the ionic size is of significant importance in predicting a finite self energy for an ion in an inhomogeneous medium. Asymptotic approximation is proposed for the solution of a generalized Debye-Hückel equation, which has been shown to capture the ionic correlation and dielectric self energy. Through simulating ionic distribution surrounding a macroion, the modified self-consistent field model is shown to agree with particle-based Monte Carlo simulations. Numerical results for symmetric and asymmetric electrolytes demonstrate that the model is able to predict the charge inversion at high correlation regime in the presence of multivalent interfacial ions which is beyond the mean-field theory and also show strong effect to double layer structure due to the space- or field-dependent dielectric permittivity.

Self-Consistency of the Theory of Elementary Stage Rates of Reversible Processes and the Equilibrium Distribution of Reaction Mixture Components

NASA Astrophysics Data System (ADS)

Tovbin, Yu. K.

2018-06-01

An analysis is presented of one of the key concepts of physical chemistry of condensed phases: the theory self-consistency in describing the rates of elementary stages of reversible processes and the equilibrium distribution of components in a reaction mixture. It posits that by equating the rates of forward and backward reactions, we must obtain the same equation for the equilibrium distribution of reaction mixture components, which follows directly from deducing the equation in equilibrium theory. Ideal reaction systems always have this property, since the theory is of a one-particle character. Problems arise in considering interparticle interactions responsible for the nonideal behavior of real systems. The Eyring and Temkin approaches to describing nonideal reaction systems are compared. Conditions for the self-consistency of the theory for mono- and bimolecular processes in different types of interparticle potentials, the degree of deviation from the equilibrium state, allowing for the internal motions of molecules in condensed phases, and the electronic polarization of the reagent environment are considered within the lattice gas model. The inapplicability of the concept of an activated complex coefficient for reaching self-consistency is demonstrated. It is also shown that one-particle approximations for considering intermolecular interactions do not provide a theory of self-consistency for condensed phases. We must at a minimum consider short-range order correlations.

Self-consistent approach for neutral community models with speciation

NASA Astrophysics Data System (ADS)

Haegeman, Bart; Etienne, Rampal S.

2010-03-01

Hubbell’s neutral model provides a rich theoretical framework to study ecological communities. By incorporating both ecological and evolutionary time scales, it allows us to investigate how communities are shaped by speciation processes. The speciation model in the basic neutral model is particularly simple, describing speciation as a point-mutation event in a birth of a single individual. The stationary species abundance distribution of the basic model, which can be solved exactly, fits empirical data of distributions of species’ abundances surprisingly well. More realistic speciation models have been proposed such as the random-fission model in which new species appear by splitting up existing species. However, no analytical solution is available for these models, impeding quantitative comparison with data. Here, we present a self-consistent approximation method for neutral community models with various speciation modes, including random fission. We derive explicit formulas for the stationary species abundance distribution, which agree very well with simulations. We expect that our approximation method will be useful to study other speciation processes in neutral community models as well.

The structure of mass-loading shocks. [interaction of solar wind with cometary coma or local interstellar medium using two-fluid model

NASA Technical Reports Server (NTRS)

Zank, G. P.; Khabibrakhmanov, I. KH.; Story, T.

1993-01-01

A new two-fluid model which describes mass loading in the solar wind (e.g., the interaction of the solar wind with a cometary coma or the local interstellar medium) is presented. The self-consistent back-reaction of the mass-loaded ions is included through their effective scattering in low-frequency MHD turbulence and the invocation of a diffusive approximation. Such an approximation has the advantage of introducing self-consistent dissipation coefficients into the governing equations, thereby facilitating the investigation of the internal structure of shocks in mass-loading environments. To illustrate the utility of the new model, we consider the structure of cometary shocks in the hypersonic one-dimensional limit, finding that the incoming solar wind is slowed by both mass loading and the development of a large cometary ion pressure gradient. The shock is broadened and smoothed by the cometary ions with a thickness of the order of the cometary ion diffusion scale.

Anharmonic vibrational spectra and mode-mode couplings analysis of 2-aminopyridine

NASA Astrophysics Data System (ADS)

Faizan, Mohd; Alam, Mohammad Jane; Afroz, Ziya; Bhat, Sheeraz Ahmad; Ahmad, Shabbir

2018-01-01

Vibrational spectra of 2-aminopyridine (2AP) have been analyzed using the vibrational self-consistence field theory (VSCF), correlated corrected vibrational self-consistence field theory (CC-VSCF) and vibrational perturbation theory (VPT2) at B3LYP/6-311G(d,p) framework. The mode-mode couplings affect the vibrational frequencies and intensities. The coupling integrals between pairs of normal modes have been obtained on the basis of quartic force field (2MR-QFF) approximation. The overtone and combination bands are also assigned in the FTIR spectrum with the help of anharmonic calculation at VPT2 method. A statistical analysis of deviations shows that estimated anharmonic frequencies are closer to the experiment over harmonic approximation. Furthermore, the anharmonic correction has also been carried out for the dimeric structure of 2AP. The fundamental vibration bands have been assigned on the basis of potential energy distribution (PED) and visual look over the animated modes. Other important molecular properties such as frontier molecular orbitals and molecular electrostatics potential mapping have also been analyzed.

Risk factors for diagnosed intentional self-injury: a total population-based study.

PubMed

Modén, Birgit; Ohlsson, Henrik; Merlo, Juan; Rosvall, Maria

2014-04-01

Few studies investigate predictors of intentional self-injury over time in non-clinical samples. By using longitudinal data from the whole population of the county of Scania, Sweden, aged 18 years and over (N = 936 449), we aim to identify risk factors for non-fatal diagnosed intentional self-injury. Groups at risk of repeat episodes of self-injury will be identified. Information on hospital stays and outpatient specialized care visits registered as intentional self-injury was collected from the Region Skåne Healthcare database in 2007. These injuries were studied in relation to sociodemographic factors, previous disease, substance abuse and psychotropic drug treatment at baseline. There were increased odds of diagnosed intentional self-injury during follow-up in association with being single, of young or middle age, having low income and being born in the Nordic countries. Presence of neurological or psychiatric disease, substance abuse and previous assault-related injury were also strongly associated with future intentional self-injury. The use of psychotropic drugs showed a clear dose-response relationship with intentional self-injury during follow-up. Those diagnosed with self-injury in the 3-year period before baseline had more than 10 times increased odds of a new episode of intentional self-injury. The odds of repeated episodes of self-injury among subjects born in Europe, but outside Sweden, were less than half those seen for subjects born in Sweden. The present study, based on a total general population, expands the knowledge base regarding intentional self-injury in adults, repeat behaviour and its associations with sociodemographic variables, substance use and disease in both men and women.

Reconciling phase diffusion and Hartree-Fock approximation in condensate systems

NASA Astrophysics Data System (ADS)

Giorgi, Gian Luca; de Pasquale, Ferdinando

2012-01-01

Despite the weakly interacting regime, the physics of Bose-Einstein condensates is widely affected by particle-particle interactions. They determine quantum phase diffusion, which is known to be the main cause of loss of coherence. Studying a simple model of two interacting Bose systems, we show how to predict the appearance of phase diffusion beyond the Bogoliubov approximation, providing a self-consistent treatment in the framework of a generalized Hartree-Fock-Bogoliubov perturbation theory.

Emotions and cognitions as correlates of early adolescent sexual behavior among Dominican youth in the United States and Dominican Republic.

PubMed

Guilamo-Ramos, Vincent; Jaccard, James; Lushin, Viktor; Robles, Gabriel; Lee, Jane; Quiñones, Zahira

2013-03-01

The present study examined cognitive and emotional correlates of sexual decision-making among three groups of Dominican adolescents: (a) Dominican youth who were born and raised in New York City, (b) Dominican youth who recently immigrated to New York City from the Dominican Republic, and (c) Dominican adolescents who were born and currently reside in the Dominican Republic. Data were collected via self-administered questionnaires from Dominican mother-adolescent dyads in New York City (n = 1,008) and the Dominican Republic (n = 213). Across groups, positive emotion constructs were consistently among the most important correlates of intentions to engage in sexual intercourse while issues related to STIs and HIV showed the lowest correlations. Interestingly, positive correlations with intentions to engage in intercourse were found among Dominican-residing males, as were positive correlations with intentions among Dominican-residing females. The implications for HIV prevention programs for Dominican youth are discussed.

Variational treatment of electron-polyatomic-molecule scattering calculations using adaptive overset grids

NASA Astrophysics Data System (ADS)

Greenman, Loren; Lucchese, Robert R.; McCurdy, C. William

2017-11-01

The complex Kohn variational method for electron-polyatomic-molecule scattering is formulated using an overset-grid representation of the scattering wave function. The overset grid consists of a central grid and multiple dense atom-centered subgrids that allow the simultaneous spherical expansions of the wave function about multiple centers. Scattering boundary conditions are enforced by using a basis formed by the repeated application of the free-particle Green's function and potential Ĝ0+V ̂ on the overset grid in a Born-Arnoldi solution of the working equations. The theory is shown to be equivalent to a specific Padé approximant to the T matrix and has rapid convergence properties, in both the number of numerical basis functions employed and the number of partial waves employed in the spherical expansions. The method is demonstrated in calculations on methane and CF4 in the static-exchange approximation and compared in detail with calculations performed with the numerical Schwinger variational approach based on single-center expansions. An efficient procedure for operating with the free-particle Green's function and exchange operators (to which no approximation is made) is also described.

Theory of electron capture from a hydrogen-like ion by a bare ion with extensions to inner-shell capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alston, S.G.

1982-01-01

A complete systematic derivation is given of a new approximation for the calculation of the cross section for electron capture from a hydrogen-like ion of large nuclear charge Z/sub T/e by a bare ion of charge Z/sub p/e moving with speed v. The amplitude in the wave treatment is obtained through consistent expansion in the small parameters Z/sub p//Z/sub T/ and Z/sub p/e/sup 2//hv; however, the ratio Z/sub T/e/sup 2//hv is not assumed small. Electron-target nucleus interactions are included to all orders and electron-projectile interactions were included consistently to first order so that the theory is called the strong potentialmore » Born (SPB). Following a careful analysis of the approach to the energy shell, an off-shell factor is seen to arise which does not appear in the impulse approximation (IA). The effects of this factor on the capture amplitude are explored. It is shown that, in comparison with the IA, the correct weighting of the target spectrum of intermediate states in the SPB significantly alters the 1s ..-->.. ns cross section and at the same time makes peaking approximations to the amplitude more realistic, even for intermediate velocity Z/sub p/e/sup 2//h<« less

Exploring Disparities and Variability in Perceptions and Self-Reported Colorectal Cancer Screening Among Three Ethnic Subgroups of U.S. Blacks

PubMed Central

Gwede, Clement K.; William, Claire M.; Thomas, Kamilah B.; Tarver, Will L.; Quinn, Gwendolyn P.; Vadaparampil, Susan T.; Kim, Jongphil; Lee, Ji-Hyun; Meade, Cathy D.

2010-01-01

Purpose/Objectives To explore perceptions of colorectal cancer (CRC) and self-reported CRC screening behaviors among ethnic subgroups of U.S. blacks. Design Descriptive, cross-sectional, exploratory, developmental pilot. Setting Medically underserved areas in Hillsborough County, FL. Sample 62 men and women aged 50 years or older. Ethnic subgroup distribution included 22 African American, 20 English-speaking Caribbean-born, and 20 Haitian-born respondents. Methods Community-based participatory research methods were used to conduct face-to-face individual interviews in the community. Main Research Variables Ethnic subgroup, health access, perceptions of CRC (e.g., awareness of screening tests, perceived risk, perceived barriers to screening), healthcare provider recommendation, and self-reported CRC screening. Findings Awareness of CRC screening tests, risk perception, healthcare provider recommendation, and self-reported use of screening were low across all subgroups. However, only 55% of Haitian-born participants had heard about the fecal occult blood test compared to 84% for English-speaking Caribbean-born participants and 91% for African Americans. Similarly, only 15% of Haitian-born respondents had had a colonoscopy compared to 50% for the English-speaking Caribbean and African American subgroups. Conclusions This exploratory, developmental pilot study identified lack of awareness, low risk perception, and distinct barriers to screening. The findings support the need for a larger community-based study to elucidate and address disparities among subgroups. Implications for Nursing Nurses play a major role in reducing cancer health disparities through research, education, and quality care. Recognition of the cultural diversity of the U.S. black population can help nurses address health disparities and contribute to the health of the community. PMID:20797950

Energy density at a buffet-style lunch differs for adolescents born at high and low risk of obesity

PubMed Central

Kral, Tanja V.E.; Stunkard, Albert J.; Berkowitz, Robert I.; Stettler, Nicolas; Stallings, Virginia A.; Kabay, April; Faith, Myles S.

2009-01-01

The energy density (ED; kcal/g) of foods, when manipulated in the laboratory, affects short-term energy intake. The aim of this study was to examine if, when given a choice, dietary ED (foods only) and energy intake (expressed as a percentage of subjects’ estimated daily energy requirement) at a self-selected, single meal differs for teens born with a different familial predisposition to obesity and as a function of their sex. Subjects (13 males, 17 females) were 12 years of age and born at high-risk (HR; n = 15) or low-risk (LR; n = 15) for obesity based on maternal pre-pregnancy body mass index (BMI; kg/m2). The buffet meal, served for lunch and consumed ad libitum, consisted of a variety of foods and beverages with a range in ED. HR subjects consumed a more energy-dense meal (foods only) than LR subjects (1.84 vs. 1.42 kcal/g; P = 0.02) and males consumed a more energy-dense meal than females (1.83 vs. 1.43 kcal/g; P = 0.03). Total energy intake, when expressed as a percentage of subjects’ daily EER, did not differ between HR and LR subjects (42% vs. 33%; P = 0.16). Males, compared to females, consumed ∼ 59% more energy from foods and beverages during the meal (46 vs. 29%; P = 0.008). During a single multi-item lunch meal, teens with a familial predisposition to obesity and males, independent of their obesity risk status, self-selected a more energy-dense meal. Familial risk for obesity, through either genetic or environmental pathways, may facilitate a more energy-dense diet. PMID:19778749

Energy density at a buffet-style lunch differs for adolescents born at high and low risk of obesity.

PubMed

Kral, Tanja V E; Stunkard, Albert J; Berkowitz, Robert I; Stettler, Nicolas; Stallings, Virginia A; Kabay, April; Faith, Myles S

2009-12-01

The energy density (ED; kcal/g) of foods, when manipulated in the laboratory, affects short-term energy intake. The aim of this study was to examine if, when given a choice, dietary ED (foods only) and energy intake (expressed as a percentage of subjects' estimated daily energy requirement; EER) at a self-selected, single meal differ for teens born with a different familial predisposition to obesity and as a function of their sex. Subjects (13 males, 17 females) were 12years of age and born at high risk (HR; n=15) or low risk (LR; n=15) for obesity based on maternal pre-pregnancy body mass index (BMI; kg/m(2)). The buffet meal, served for lunch and consumed ad libitum, consisted of a variety of foods and beverages with a range in ED. HR subjects consumed a more energy-dense meal (foods only) than LR subjects (1.84 vs. 1.42kcal/g; P=0.02) and males consumed a more energy-dense meal than females (1.83 vs. 1.43kcal/g; P=0.03). Total energy intake, when expressed as a percentage of subjects' daily EER, did not differ between HR and LR subjects (42% vs. 33%; P=0.16). Males, compared to females, consumed ~59% more energy from foods and beverages during the meal (46 vs. 29%; P=0.008). During a single multi-item lunch meal, teens with a familial predisposition to obesity and males, independent of their obesity risk status, self-selected a more energy-dense meal. Familial risk for obesity, through either genetic or environmental pathways, may facilitate a more energy-dense diet.

Active matter beyond mean-field: ring-kinetic theory for self-propelled particles.

PubMed

Chou, Yen-Liang; Ihle, Thomas

2015-02-01

Recently, Hanke et al. [Phys. Rev. E 88, 052309 (2013)] showed that mean-field kinetic theory fails to describe collective motion in soft active colloids and that correlations must not be neglected. Correlation effects are also expected to be essential in systems of biofilaments driven by molecular motors and in swarms of midges. To obtain correlations in an active matter system from first principles, we derive a ring-kinetic theory for Vicsek-style models of self-propelled agents from the exact N-particle evolution equation in phase space. The theory goes beyond mean-field and does not rely on Boltzmann's approximation of molecular chaos. It can handle precollisional correlations and cluster formation, which are both important to understand the phase transition to collective motion. We propose a diagrammatic technique to perform a small-density expansion of the collision operator and derive the first two equations of the Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy. An algorithm is presented that numerically solves the evolution equation for the two-particle correlations on a lattice. Agent-based simulations are performed and informative quantities such as orientational and density correlation functions are compared with those obtained by ring-kinetic theory. Excellent quantitative agreement between simulations and theory is found at not-too-small noises and mean free paths. This shows that there are parameter ranges in Vicsek-like models where the correlated closure of the BBGKY hierarchy gives correct and nontrivial results. We calculate the dependence of the orientational correlations on distance in the disordered phase and find that it seems to be consistent with a power law with an exponent around -1.8, followed by an exponential decay. General limitations of the kinetic theory and its numerical solution are discussed.

Coherent states, quantum gravity, and the Born-Oppenheimer approximation. I. General considerations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stottmeister, Alexander, E-mail: alexander.stottmeister@gravity.fau.de; Thiemann, Thomas, E-mail: thomas.thiemann@gravity.fau.de

2016-06-15

This article, as the first of three, aims at establishing the (time-dependent) Born-Oppenheimer approximation, in the sense of space adiabatic perturbation theory, for quantum systems constructed by techniques of the loop quantum gravity framework, especially the canonical formulation of the latter. The analysis presented here fits into a rather general framework and offers a solution to the problem of applying the usual Born-Oppenheimer ansatz for molecular (or structurally analogous) systems to more general quantum systems (e.g., spin-orbit models) by means of space adiabatic perturbation theory. The proposed solution is applied to a simple, finite dimensional model of interacting spin systems,more » which serves as a non-trivial, minimal model of the aforesaid problem. Furthermore, it is explained how the content of this article and its companion affect the possible extraction of quantum field theory on curved spacetime from loop quantum gravity (including matter fields).« less

Generalized Born Models of Macromolecular Solvation Effects

NASA Astrophysics Data System (ADS)

Bashford, Donald; Case, David A.

2000-10-01

It would often be useful in computer simulations to use a simple description of solvation effects, instead of explicitly representing the individual solvent molecules. Continuum dielectric models often work well in describing the thermodynamic aspects of aqueous solvation, and approximations to such models that avoid the need to solve the Poisson equation are attractive because of their computational efficiency. Here we give an overview of one such approximation, the generalized Born model, which is simple and fast enough to be used for molecular dynamics simulations of proteins and nucleic acids. We discuss its strengths and weaknesses, both for its fidelity to the underlying continuum model and for its ability to replace explicit consideration of solvent molecules in macromolecular simulations. We focus particularly on versions of the generalized Born model that have a pair-wise analytical form, and therefore fit most naturally into conventional molecular mechanics calculations.

The self-assembly of particles with isotropic interactions: Using DNA coated colloids to create designer nanomaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, R. B.; Dion, S.; Konigslow, K. von

Self-consistent field theory equations are presented that are suitable for use as a coarse-grained model for DNA coated colloids, polymer-grafted nanoparticles and other systems with approximately isotropic interactions. The equations are generalized for arbitrary numbers of chemically distinct colloids. The advantages and limitations of such a coarse-grained approach for DNA coated colloids are discussed, as are similarities with block copolymer self-assembly. In particular, preliminary results for three species self-assembly are presented that parallel results from a two dimensional ABC triblock copolymer phase. The possibility of incorporating crystallization, dynamics, inverse statistical mechanics and multiscale modelling techniques are discussed.

Acculturation and Sleep among a Multiethnic Sample of Women: The Study of Women's Health Across the Nation (SWAN)

PubMed Central

Hale, Lauren; Troxel, Wendy M.; Kravitz, Howard M.; Hall, Martica H.; Matthews, Karen A.

2014-01-01

Study Objectives: Mexican immigrants to the United States report longer sleep duration and fewer sleep complaints than their US-born counterparts. To investigate whether this effect extends to other immigrant groups, we examined whether the prevalence of self-reported sleep complaints is higher among US-born Hispanic/Latina, Chinese, and Japanese immigrant women compared to their first-generation immigrant ethnic counterparts as well as to US-born whites. We examined whether these associations persisted after adjusting for sociodemographic and health characteristics and whether acculturation mediated the effects. Design: Cross-sectional observational study. Setting: Multisite study in Oakland, CA; Los Angeles, CA; and Newark, NJ. Participants: Hispanic/Latina (n = 196), Chinese (n = 228), Japanese (n = 271) and non-Hispanic white (n = 485) women (mean age = 46 y, range 42-52 y) participating in the Study of Women's Health Across the Nation (SWAN); 410 or 59.0% of the nonwhites were first-generation immigrants. Interventions: None. Measurements and Results: Questionnaires were used to assess sleep complaints, race/ethnicity, immigrant status, language acculturation (use of English language), and sociodemographic and health variables. Approximately 25% of first-generation immigrant women reported sleep complaints compared to 37% of those who were US-born nonwhites and 42% of US-born whites. Multivariable adjusted logistic regression analyses showed that US-born nonwhites had higher odds of reporting any sleep complaints (odds ratio = 2.1, 95% confidence interval [CI] 1.5-3.0), compared to first-generation immigrants. Women with higher levels of language acculturation had greater odds of reporting any sleep complaint compared to those with less language acculturation. Adjustment for language acculturation mediated 40.4% (95% CI 28.5-69.8) of the association between immigrant status and any sleep complaint. When results were stratified by race/ethnicity, significant mediation effects of acculturation were only found for Hispanic/Latina and Japanese women, but not for Chinese women. Conclusion: US-born Hispanic/Latina, Chinese, and Japanese immigrants were more likely to report sleep complaints than their first-generation ethnic counterparts, a finding largely explained by language acculturation and unmeasured factors associated with language acculturation. Citation: Hale L; Troxel WM; Kravitz HM; Hall MH; Matthews KA. Acculturation and sleep among a multiethnic sample of women: the Study of Women's Health Across the Nation (SWAN). SLEEP 2014;37(2):309-317. PMID:24497659

The Association Between Immigration Status and Office-based Medical Provider Visits for Cancer Patients in the United States.

PubMed

Wang, Yang; Wilson, Fernando A; Chen, Li-Wu

2017-06-01

We examined differences in cancer-related office-based provider visits associated with immigration status in the United States. Data from the 2007-2012 Medical Expenditure Panel Survey and National Health Interview Survey included adult patients diagnosed with cancer. Univariate analyses described distributions of cancer-related office-based provider visits received, expenditures, visit characteristics, as well as demographic, socioeconomic, and health covariates, across immigration groups. We measured the relationships of immigrant status to number of visits and associated expenditure within the past 12 months, adjusting for age, sex, educational attainment, race/ethnicity, self-reported health status, time since cancer diagnosis, cancer remission status, marital status, poverty status, insurance status, and usual source of care. We finally performed sensitivity analyses for regression results by using the propensity score matching method to adjust for potential selection bias. Noncitizens had about 2 fewer visits in a 12-month period in comparison to US-born citizens (4.0 vs. 5.9). Total expenditure per patient was higher for US-born citizens than immigrants (not statistically significant). Noncitizens (88.3%) were more likely than US-born citizens (76.6%) to be seen by a medical doctor during a visit. Multivariate regression results showed that noncitizens had 42% lower number of visiting medical providers at office-based settings for cancer care than US-born citizens, after adjusting for all the other covariates. There were no significant differences in expenditures across immigration groups. The propensity score matching results were largely consistent with those in multivariate-adjusted regressions. Results suggest targeted interventions are needed to reduce disparities in utilization between immigrants and US-born citizen cancer patients.

Children's and adolescent's perspectives on cleft lip and/or palate.

PubMed

Hall, Melanie J; Gibson, Barry J; James, Allison; Rodd, Helen D

2013-03-01

Children's voices are being increasingly acknowledged in health care research. The aim of this study was to explore children's and young people's perspectives of being born with a cleft lip and/or palate. The research took a qualitative approach that consisted of two interviews with each child, drawing on child-centered methodologies and techniques. The initial interview focused on children's general life stories, and these often encompassed a discussion about cleft lip and/or palate. The follow-up interview explored specific aspects of the condition and related treatment. The self-selected sample consisted of 17 children and young people (eight boys, nine girls) with cleft lip and/or palate, aged 8 to 17 years, who received treatment at a dental hospital in the U.K. Children's and young people's accounts identified a number of themes including how they became aware that they had been born with the condition, their views of the treatment pathway, and how it related to who they are. This study highlights the value of including young people's perspectives in oral health-related research. It has allowed a deeper insight into cleft lip and palate and shows that young people can contribute their views and experiences about services which demonstrate that these could be incorporated into service evaluations.

Birth Order and Self-Concept in Adolescence.

ERIC Educational Resources Information Center

Gecas, Viktor; Pasley, Kay

1983-01-01

Very little support was found for any of several hypotheses concerning the effect of birth order on self-concept in adolescents. The strongest support was found for the hypothesis that middle-borns have the lowest self-evaluations. (Author/BW)

Genetic correlations between body weight change and reproduction traits in Merino ewes depend on age.

PubMed

Rose, G; Mulder, H A; van der Werf, J H J; Thompson, A N; van Arendonk, J A M

2014-08-01

Merino sheep in Australia experience periods of variable feed supply. Merino sheep can be bred to be more resilient to this variation by losing less BW when grazing poor quality pasture and gaining more BW when grazing good quality pasture. Therefore, selection on BW change might be economically attractive but correlations with other traits in the breeding objective need to be known. The genetic correlations (rg) between BW, BW change, and reproduction were estimated using records from approximately 7,350 fully pedigreed Merino ewes managed at Katanning in Western Australia. Number of lambs and total weight of lambs born and weaned were measured on approximately 5,300 2-yr-old ewes, approximately 4,900 3-yr-old ewes, and approximately 3,600 4-yr-old ewes. On a proportion of these ewes BW change was measured: approximately 1,950 2-yr-old ewes, approximately 1,500 3-yr-old ewes, and approximately 1,100 4-yr-old ewes. The BW measurements were for 3 periods. The first period was during mating period over 42 d on poor pasture. The second period was during pregnancy over 90 d for ewes that got pregnant on poor and medium quality pasture. The third period was during lactation over 130 d for ewes that weaned a lamb on good quality pasture. Genetic correlations between weight change and reproduction were estimated within age classes. Genetic correlations were tested to be significantly greater magnitude than 0 using likelihood ratio tests. Nearly all BW had significant positive genetic correlations with all reproduction traits. In 2-yr-old ewes, BW change during the mating period had a positive genetic correlation with number of lambs weaned (rg = 0.58); BW change during pregnancy had a positive genetic correlation with total weight of lambs born (rg = 0.33) and a negative genetic correlation with number of lambs weaned (rg = -0.49). All other genetic correlations were not significantly greater magnitude than 0 but estimates of genetic correlations for 3-yr-old ewes were generally consistent with these findings. The direction of the genetic correlations mostly coincided with the energy requirements of the ewes and the stage of maturity of the ewes. In conclusion, optimized selection strategies on BW changes to increase resilience will depend on the genetic correlations with reproduction and are dependent on age.

The effect of acculturation and discrimination on mental health symptoms and risk behaviors among adolescent migrants in Israel.

PubMed

Nakash, Ora; Nagar, Maayan; Shoshani, Anat; Zubida, Hani; Harper, Robin A

2012-07-01

This study examines the role of acculturation, perceived discrimination, and self-esteem in predicting the mental health symptoms and risk behaviors among 1.5 and second generation non-Jewish adolescents born to migrant families compared with native-born Jewish Israeli adolescents in Israel. Participants included n = 65 1.5 migrant adolescents, n = 60 second generation migrant adolescents, and n = 146 age, gender, and socioeconomic matched sample of native-born Jewish Israelis. Participants completed measures of acculturation pattern, perceived discrimination, and self-esteem as well as measures of mental health symptoms and risk behaviors. Results show that migrant adolescents across generations reported worse mental health symptoms compared with native-born Jewish Israelis. However, only the 1.5 generation migrants reported higher engagement in risk behaviors compared with second generation migrants and native-born Jewish Israelis. Our findings further showed that acculturation plays an important role in predicting the mental health status of migrant youth, with those characterized with integrated acculturative pattern reporting lower mental health symptoms compared with assimilated acculturation pattern. Importantly, contextual factors, such as higher perception of discrimination in the receiving culture as well as individual factors such as lower self-esteem and female gender were strongly associated with worse mental health symptoms. The findings manifest the complex relationship between contextual factors and individual level variables in the acculturative process of migrants as well as the importance of examining the effect of migration generation on mental health outcomes.

Self-perceived health among Eastern European immigrants over 50 living in Western Europe.

PubMed

Lanari, D; Bussini, O; Minelli, L

2015-01-01

This paper examines whether Eastern European immigrants aged 50 and over living in Northern and Western Europe face a health disadvantage in terms of self-perceived health, with respect to the native-born. We also examined health changes over time (2004-2006-2010) through the probabilities of transition among self-perceived health states, and how they vary according to nativity status and age group. Data were obtained from the Survey of Health, Ageing and Retirement in Europe (SHARE). Logistic regressions and probabilities of transition were used. Results emphasise the health disadvantage of Eastern European immigrants living in Germany, France and  Sweden with respect to the native-born, even after controlling for socio-economic status. Probabilities of transition also evidenced that people born in Eastern Europe were more likely to experience worsening health and less likely to recover from sickness. This paper suggests that health inequalities do not affect immigrant groups in equal measure and confirm the poorer and more steeply deteriorating health status of Eastern European immigrants.

Expressive Language in Preschoolers Born Preterm: Results of Language Sample Analysis and Standardized Assessment

ERIC Educational Resources Information Center

Imgrund, Caitlin

2017-01-01

Children born preterm constitute one of the largest populations of children at risk for the development of language impairments. A little over one in ten pregnancies result in a preterm birth and approximately 25% of these children go on to experience subsequent difficulties with language (CDC, 2015; Foster-Cohen, Friesen, Champion, &…

Immunological control of ticks and tick-borne diseases that impact cattle health and production in Mexico

USDA-ARS?s Scientific Manuscript database

The cattle industry is one of the most important agroeconomic activities in Mexico. The national herd is estimated to include approximately 33.5 million head of cattle. Ticks and tick-borne diseases are principal factors with a negative impact on cattle health and production in Mexico. The most econ...

Work Hours of Immigrant Versus U.S.-Born Female Workers.

PubMed

Bae, Sung-Heui

2017-10-01

This study was a secondary analysis of cross-sectional data extracted from the 2011-2012 California Health Interview Survey. Data from 8,931 full-time (i.e., 21 hours or more per week) women workers aged 18 to 85 years were analyzed to examine the nature and prevalence of immigrant female workers' work hours, overtime, and related factors in the United States compared to U.S.-born female workers. Results showed that foreign-born female workers did not work longer hours than U.S.-born female workers. Foreign-born female workers who reported poor health worked longer hours than did their U.S.-born counterparts. Foreign-born female workers who were self-employed or worked in family businesses tended to work longer hours than did those women who worked for private companies or nonprofit organizations.

Academic Self-Concept, Gender and Single-Sex Schooling

ERIC Educational Resources Information Center

Sullivan, Alice

2009-01-01

This article assesses gender differences in academic self-concept for a cohort of children born in 1958 (the National Child Development Study). It addresses the question of whether attending single-sex or co-educational schools affected students' perceptions of their own academic abilities (academic self-concept). Academic self-concept was found…

Birth Order, Age-Spacing, IQ Differences, and Family Relations.

ERIC Educational Resources Information Center

Pfouts, Jane H.

1980-01-01

Very close age spacing was an obstacle to high academic performance for later borns. In family relations and self-esteem, first borns scored better and performed in school as well as their potentially much more able younger siblings, regardless of age spacing. (Author)

LUPUS I observations from the 2010 flight of the Balloon-borne large aperture submillimeter telescope for polarimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matthews, Tristan G.; Chapman, Nicholas L.; Novak, Giles

2014-04-01

The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was created by adding polarimetric capability to the BLAST experiment that was flown in 2003, 2005, and 2006. BLASTPol inherited BLAST's 1.8 m primary and its Herschel/SPIRE heritage focal plane that allows simultaneous observation at 250, 350, and 500 μm. We flew BLASTPol in 2010 and again in 2012. Both were long duration Antarctic flights. Here we present polarimetry of the nearby filamentary dark cloud Lupus I obtained during the 2010 flight. Despite limitations imposed by the effects of a damaged optical component, we were able to clearly detect submillimeter polarizationmore » on degree scales. We compare the resulting BLASTPol magnetic field map with a similar map made via optical polarimetry. (The optical data were published in 1998 by J. Rizzo and collaborators.) The two maps partially overlap and are reasonably consistent with one another. We compare these magnetic field maps to the orientations of filaments in Lupus I, and we find that the dominant filament in the cloud is approximately perpendicular to the large-scale field, while secondary filaments appear to run parallel to the magnetic fields in their vicinities. This is similar to what is observed in Serpens South via near-IR polarimetry, and consistent with what is seen in MHD simulations by F. Nakamura and Z. Li.« less

A possible line feature at 73 keV from the Crab Nebula

NASA Technical Reports Server (NTRS)

Ling, J. C.; Mahoney, W. A.; Willett, J. B.; Jacobson, A. S.

1979-01-01

Evidence is reported for a possible line feature at 73 keV from the Crab Nebula. The experiment was conducted with a balloon-borne high-resolution gamma-ray spectrometer on June 10, 1974, over Palestine, Texas. The intensity and the width of the line derived from the fitting of these data are approximately 0.0038 photon per (sq cm-sec) and less than 4.9 keV FWHM, respectively. The line is superposed on a power-law continuum of 11.2 E to the -2.16 photons per (sq cm-keV) in the energy range from 53 to 300 keV, which is consistent with other measurements of the Crab Nebula spectrum.

Communication: On the calculation of time-dependent electron flux within the Born-Oppenheimer approximation: A flux-flux reflection principle

NASA Astrophysics Data System (ADS)

Albert, Julian; Hader, Kilian; Engel, Volker

2017-12-01

It is commonly assumed that the time-dependent electron flux calculated within the Born-Oppenheimer (BO) approximation vanishes. This is not necessarily true if the flux is directly determined from the continuity equation obeyed by the electron density. This finding is illustrated for a one-dimensional model of coupled electronic-nuclear dynamics. There, the BO flux is in perfect agreement with the one calculated from a solution of the time-dependent Schrödinger equation for the coupled motion. A reflection principle is derived where the nuclear BO flux is mapped onto the electronic flux.

First-principles calculations reveal controlling principles for carrier mobilities in semiconductors

DOE PAGES

Wu, Yu -Ning; Zhang, Xiaoguang; Pantelides, Sokrates T.; ...

2016-10-11

It has long been believed that carrier mobilities in semiconductors can be calculated by Fermi s golden rule (Born approximation). Phenomenological models for scattering amplitudes are typically used for engineering- level device modeling. Here we introduce a parameter-free, first-principles approach based on complex- wavevector energy bands that does not invoke the Born approximation. We show that phonon-limited mobility is controlled by low-resistivity percolation paths and that in ionized-impurity scattering one must account for the effect of the screening charge, which cancels most of the Coulomb tail.Finally, calculated electron mobilities in silicon are in agreement with experimental data.

Comparing the role of the height of men and women in the marriage market.

PubMed

Yamamura, Eiji; Tsutsui, Yoshiro

2017-08-01

This paper explores how the role of men and women's height in the marriage market has changed across generations. Using individual-level data from Japan, we compared the effect of height on marriages between men and women, and investigated how the effect of height on marriage has changed across generations. Our key findings are: (1) for men born before 1965, a 1% increase in height led to an approximately 0.56% increase in the probability of being married. Conversely, for women born before 1965, a 1% increase in height led to an approximately 0.56% decrease in the probability of being married. (2) For men born in or after 1965, a 1% increase in height led to an approximately 1.05% (0.18%) increase (decrease) in the probability of being married (divorced). However, the height effect was not present for women. Japan experienced astounding economic development after World War II, which resulted in changes in its economic and social structure. These changes may have also altered the role of height for Japanese men and women in the marriage market. Copyright © 2017 Elsevier B.V. All rights reserved.

Compton scattering collision module for OSIRIS

NASA Astrophysics Data System (ADS)

Del Gaudio, Fabrizio; Grismayer, Thomas; Fonseca, Ricardo; Silva, Luís

2017-10-01

Compton scattering plays a fundamental role in a variety of different astrophysical environments, such as at the gaps of pulsars and the stagnation surface of black holes. In these scenarios, Compton scattering is coupled with self-consistent mechanisms such as pair cascades. We present the implementation of a novel module, embedded in the self-consistent framework of the PIC code OSIRIS 4.0, capable of simulating Compton scattering from first principles and that is fully integrated with the self-consistent plasma dynamics. The algorithm accounts for the stochastic nature of Compton scattering reproducing without approximations the exchange of energy between photons and unbound charged species. We present benchmarks of the code against the analytical results of Blumenthal et al. and the numerical solution of the linear Kompaneets equation and good agreement is found between the simulations and the theoretical models. This work is supported by the European Research Council Grant (ERC- 2015-AdG 695088) and the Fundao para a Céncia e Tecnologia (Bolsa de Investigao PD/BD/114323/2016).

Self-consistent perturbation theory for two dimensional twisted bilayers

NASA Astrophysics Data System (ADS)

Shirodkar, Sharmila N.; Tritsaris, Georgios A.; Kaxiras, Efthimios

Theoretical modeling and ab-initio simulations of two dimensional heterostructures with arbitrary angles of rotation between layers involve unrealistically large and expensive calculations. To overcome this shortcoming, we develop a methodology for weakly interacting heterostructures that treats the effect of one layer on the other as perturbation, and restricts the calculations to their primitive cells. Thus, avoiding computationally expensive supercells. We start by approximating the interaction potential between the twisted bilayers to that of a hypothetical configuration (viz. ideally stacked untwisted layers), which produces band structures in reasonable agreement with full-scale ab-initio calculations for commensurate and twisted bilayers of graphene (Gr) and Gr/hexagonal boron nitride (h-BN) heterostructures. We then self-consistently calculate the charge density and hence, interaction potential of the heterostructures. In this work, we test our model for bilayers of various combinations of Gr, h-BN and transition metal dichalcogenides, and discuss the advantages and shortcomings of the self-consistently calculated interaction potential. Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.

Living with the Sins of Their Fathers: An Analysis of Self-Representation of Adolescents Born of War Rape

ERIC Educational Resources Information Center

Erjavec, Karmen; Volcic; Zala

2010-01-01

Children born of war rape continue to be a taboo theme in many post-war societies, also in Bosnia and Herzegovina (BH). This study is based on in-depth interviews with eleven adolescents born of war rape in BH. The main goal is to present how these adolescents represent themselves and their life-situations. On the basis of the research we identify…

Thermodynamically self-consistent theory for the Blume-Capel model.

PubMed

Grollau, S; Kierlik, E; Rosinberg, M L; Tarjus, G

2001-04-01

We use a self-consistent Ornstein-Zernike approximation to study the Blume-Capel ferromagnet on three-dimensional lattices. The correlation functions and the thermodynamics are obtained from the solution of two coupled partial differential equations. The theory provides a comprehensive and accurate description of the phase diagram in all regions, including the wing boundaries in a nonzero magnetic field. In particular, the coordinates of the tricritical point are in very good agreement with the best estimates from simulation or series expansion. Numerical and analytical analysis strongly suggest that the theory predicts a universal Ising-like critical behavior along the lambda line and the wing critical lines, and a tricritical behavior governed by mean-field exponents.

Inclusion-Based Effective Medium Models for the Permeability of a 3D Fractured Rock Mass

NASA Astrophysics Data System (ADS)

Ebigbo, A.; Lang, P. S.; Paluszny, A.; Zimmerman, R. W.

2015-12-01

Following the work of Saevik et al. (Transp. Porous Media, 2013; Geophys. Prosp., 2014), we investigate the ability of classical inclusion-based effective medium theories to predict the macroscopic permeability of a fractured rock mass. The fractures are assumed to be thin, oblate spheroids, and are treated as porous media in their own right, with permeability kf, and are embedded in a homogeneous matrix having permeability km. At very low fracture densities, the effective permeability is given exactly by a well-known expression that goes back at least as far as Fricke (Phys. Rev., 1924). For non-trivial fracture densities, an effective medium approximation must be employed. We have investigated several such approximations: Maxwell's method, the differential method, and the symmetric and asymmetric versions of the self-consistent approximation. The predictions of the various approximate models are tested against the results of explicit numerical simulations, averaged over numerous statistical realizations for each set of parameters. Each of the various effective medium approximations satisfies the Hashin-Shtrikman (H-S) bounds. Unfortunately, these bounds are much too far apart to provide quantitatively useful estimates of keff. For the case of zero matrix permeability, the well-known approximation of Snow, which is based on network considerations rather than a continuum approach, is shown to essentially coincide with the upper H-S bound, thereby proving that the commonly made assumption that Snow's equation is an "upper bound" is indeed correct. This problem is actually characterized by two small parameters, the aspect ratio of the spheroidal fractures, α, and the permeability ratio, κ = km/kf. Two different regimes can be identified, corresponding to α < κ and κ < α, and expressions for each of the effective medium approximations are developed in both regimes. In both regimes, the symmetric version of the self-consistent approximation is the most accurate.

Scattering and absorption of massless scalar waves by Born-Infeld black holes

NASA Astrophysics Data System (ADS)

Sanchez, Pablo Alejandro; Bretón, Nora; Bergliaffa, Santiago Esteban Perez

2018-06-01

We present the results of a study of the scattering of massless planar scalar waves by a Born-Infeld black hole. The scattering and absorption cross sections are calculated using partial-wave methods. The numerical results are checked by reproducing those of the Reissner-Nordstrom black hole, and also using several approximations, with which our results are in very good agreement. The dependence of these phenomena on the effective potential, the charge of the black hole, and the value of the Born-Infeld parameter is discussed.

Bodywork: Self-Harm, Trauma, and Embodied Expressions of Pain

ERIC Educational Resources Information Center

Gurung, Kesherie

2018-01-01

Self-harm, or self-mutilation, is generally viewed in academic literature as a pathological act, usually born out of trauma and/or a psychological and personality defect. Individuals who engage in self-harm are usually seen as damaged, destructive, and pathological. While self-harm is not a desirable act, this paper argues through the narratives…

Self consistent field theory of virus assembly

NASA Astrophysics Data System (ADS)

Li, Siyu; Orland, Henri; Zandi, Roya

2018-04-01

The ground state dominance approximation (GSDA) has been extensively used to study the assembly of viral shells. In this work we employ the self-consistent field theory (SCFT) to investigate the adsorption of RNA onto positively charged spherical viral shells and examine the conditions when GSDA does not apply and SCFT has to be used to obtain a reliable solution. We find that there are two regimes in which GSDA does work. First, when the genomic RNA length is long enough compared to the capsid radius, and second, when the interaction between the genome and capsid is so strong that the genome is basically localized next to the wall. We find that for the case in which RNA is more or less distributed uniformly in the shell, regardless of the length of RNA, GSDA is not a good approximation. We observe that as the polymer-shell interaction becomes stronger, the energy gap between the ground state and first excited state increases and thus GSDA becomes a better approximation. We also present our results corresponding to the genome persistence length obtained through the tangent-tangent correlation length and show that it is zero in case of GSDA but is equal to the inverse of the energy gap when using SCFT.

Second-order Born calculation of coplanar symmetric (e, 2e) process on Mg

NASA Astrophysics Data System (ADS)

Zhang, Yong-Zhi; Wang, Yang; Zhou, Ya-Jun

2014-06-01

The second-order distorted wave Born approximation (DWBA) method is employed to investigate the triple differential cross sections (TDCS) of coplanar doubly symmetric (e, 2e) collisions for magnesium at excess energies of 6 eV-20 eV. Comparing with the standard first-order DWBA calculations, the inclusion of the second-order Born term in the scattering amplitude improves the degree of agreement with experiments, especially for backward scattering region of TDCS. This indicates that the present second-order Born term is capable to give a reasonable correction to DWBA model in studying coplanar symmetric (e, 2e) problems of two-valence-electron target in low energy range.

South Asian populations in Canada: migration and mental health.

PubMed

Islam, Farah; Khanlou, Nazilla; Tamim, Hala

2014-05-26

South Asian populations are the largest visible minority group in Canada; however, there is very little information on the mental health of these populations. The objective of this study was to determine the prevalence rates and characteristics of mental health outcomes for South Asian first-generation immigrant and second-generation Canadian-born populations. The Canadian Community Health Survey (CCHS) 2011 was used to calculate the estimated prevalence rates of the following mental health outcomes: mood disorders, anxiety disorders, fair-poor self-perceived mental health status, and extremely stressful life stress. The characteristics associated with these four mental health outcomes were determined through multivariate logistic regression analysis of merged CCHS 2007-2011 data. South Asian Canadian-born (3.5%, 95% CI 3.4-3.6%) and South Asian immigrant populations (3.5%, 95% CI 3.5-3.5%) did not vary significantly in estimated prevalence rates of mood disorders. However, South Asian immigrants experienced higher estimated prevalence rates of diagnosed anxiety disorders (3.4%, 95% CI 3.4-3.5 vs. 1.1%, 95% CI 1.1-1.1%) and self-reported extremely stressful life stress (2.6%, 95% CI 2.6-2.7% vs. 2.4%, 95% CI 2.3-2.4%) compared to their Canadian-born counterparts. Lastly, South Asian Canadian-born populations had a higher estimated prevalence rate of poor-fair self-perceived mental health status (4.4%, 95% CI 4.3-4.5%) compared to their immigrant counterparts (3.4%, 95% CI 3.3-3.4%). Different profiles of mental health determinants emerged for South Asian Canadian-born and immigrant populations. Female gender, having no children under the age of 12 in the household, food insecurity, poor-fair self-rated health status, being a current smoker, immigrating to Canada before adulthood, and taking the CCHS survey in either English or French was associated with greater risk of negative mental health outcomes for South Asian immigrant populations, while not being currently employed, having a regular medical doctor, and inactive physical activity level were associated with greater risk for South Asian Canadian-born populations. Mental health outreach programs need to be cognizant of the differences in prevalence rates and characteristics of mental health outcomes for South Asian immigrant and Canadian-born populations to better tailor mental health services to be responsive to the unique mental health needs of South Asian populations in Canada.

Derivation of the density functional theory from the cluster expansion.

PubMed

Hsu, J Y

2003-09-26

The density functional theory is derived from a cluster expansion by truncating the higher-order correlations in one and only one term in the kinetic energy. The formulation allows self-consistent calculation of the exchange correlation effect without imposing additional assumptions to generalize the local density approximation. The pair correlation is described as a two-body collision of bound-state electrons, and modifies the electron- electron interaction energy as well as the kinetic energy. The theory admits excited states, and has no self-interaction energy.

Dynamical self-arrest in symmetric and asymmetric diblock copolymer melts using a replica approach within a local theory.

PubMed

Wu, Sangwook

2009-03-01

We investigate dynamical self-arrest in a diblock copolymer melt using a replica approach within a self-consistent local method based on dynamical mean-field theory (DMFT). The local replica approach effectively predicts (chiN)_{A} for dynamical self-arrest in a block copolymer melt for symmetric and asymmetric cases. We discuss the competition of the cubic and quartic interactions in the Landau free energy for a block copolymer melt in stabilizing a glassy state depending on the chain length. Our local replica theory provides a universal value for the dynamical self-arrest in block copolymer melts with (chiN)_{A} approximately 10.5+64N;{-3/10} for the symmetric case.

Migration Timing and Parenting Practices: Contributions to Social Development in Preschoolers with Foreign-Born and Native-Born Mothers

ERIC Educational Resources Information Center

Glick, Jennifer E.; Hanish, Laura D.; Yabiku, Scott T.; Bradley, Robert H.

2012-01-01

Little is known about how key aspects of parental migration or childrearing history affect social development across children from immigrant families. Relying on data on approximately 6,400 children from the Early Childhood Longitudinal Study-Birth Cohort, analyses assessed the role of mother's age at migration on children's social development in…

CMB weak-lensing beyond the Born approximation: a numerical approach

NASA Astrophysics Data System (ADS)

Fabbian, Giulio; Calabrese, Matteo; Carbone, Carmelita

2018-02-01

We perform a complete study of the gravitational lensing effect beyond the Born approximation on the Cosmic Microwave Background (CMB) anisotropies using a multiple-lens raytracing technique through cosmological N-body simulations of the DEMNUni suite. The impact of second-order effects accounting for the non-linear evolution of large-scale structures is evaluated propagating for the first time the full CMB lensing jacobian together with the light rays trajectories. We carefully investigate the robustness of our approach against several numerical effects in the raytracing procedure and in the N-body simulation itself, and find no evidence of large contaminations. We discuss the impact of beyond-Born corrections on lensed CMB observables, and compare our results with recent analytical predictions that appeared in the literature, finding a good agreement, and extend these results to smaller angular scales. We measure the gravitationally-induced CMB polarization rotation that appears in the geodesic equation at second order, and compare this result with the latest analytical predictions. We then present the detection prospect of beyond-Born effects with the future CMB-S4 experiment. We show that corrections to the temperature power spectrum can be measured only if a good control of the extragalactic foregrounds is achieved. Conversely, the beyond-Born corrections on E and B-modes power spectra will be much more difficult to detect.

The Microwave Radiative Properties of Falling Snow Derived from Nonspherical Ice Particle Models. Part II: Initial Testing Using Radar, Radiometer and In Situ Observations

NASA Technical Reports Server (NTRS)

Olson, William S.; Tian, Lin; Grecu, Mircea; Kuo, Kwo-Sen; Johnson, Benjamin; Heymsfield, Andrew J.; Bansemer, Aaron; Heymsfield, Gerald M.; Wang, James R.; Meneghini, Robert

2016-01-01

In this study, two different particle models describing the structure and electromagnetic properties of snow are developed and evaluated for potential use in satellite combined radar-radiometer precipitation estimation algorithms. In the first model, snow particles are assumed to be homogeneous ice-air spheres with single-scattering properties derived from Mie theory. In the second model, snow particles are created by simulating the self-collection of pristine ice crystals into aggregate particles of different sizes, using different numbers and habits of the collected component crystals. Single-scattering properties of the resulting nonspherical snow particles are determined using the discrete dipole approximation. The size-distribution-integrated scattering properties of the spherical and nonspherical snow particles are incorporated into a dual-wavelength radar profiling algorithm that is applied to 14- and 34-GHz observations of stratiform precipitation from the ER-2 aircraft-borne High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) radar. The retrieved ice precipitation profiles are then input to a forward radiative transfer calculation in an attempt to simulate coincident radiance observations from the Conical Scanning Millimeter-Wave Imaging Radiometer (CoSMIR). Much greater consistency between the simulated and observed CoSMIR radiances is obtained using estimated profiles that are based upon the nonspherical crystal/aggregate snow particle model. Despite this greater consistency, there remain some discrepancies between the higher moments of the HIWRAP-retrieved precipitation size distributions and in situ distributions derived from microphysics probe observations obtained from Citation aircraft underflights of the ER-2. These discrepancies can only be eliminated if a subset of lower-density crystal/aggregate snow particles is assumed in the radar algorithm and in the interpretation of the in situ data.

Prediction and Cross-Situational Consistency of Daily Behavior across Cultures: Testing Trait and Cultural Psychology Perspectives

PubMed Central

Church, A. Timothy; Katigbak, Marcia S.; Reyes, Jose Alberto S.; Salanga, Maria Guadalupe C.; Miramontes, Lilia A.; Adams, Nerissa B.

2008-01-01

Trait and cultural psychology perspectives on the cross-situational consistency of behavior, and the predictive validity of traits, were tested in a daily process study in the United States (N = 68), an individualistic culture, and the Philippines (N = 80), a collectivistic culture. Participants completed the Revised NEO Personality Inventory (Costa & McCrae, 1992) and a measure of self-monitoring, then reported their daily behaviors and associated situational contexts for approximately 30 days. Consistent with trait perspectives, the Big Five traits predicted daily behaviors in both cultures, and relative (interindividual) consistency was observed across many, although not all, situational contexts. The frequency of various Big Five behaviors varied across relevant situational contexts in both cultures and, consistent with cultural psychology perspectives, there was a tendency for Filipinos to exhibit greater situational variability than Americans. Self-monitoring showed some ability to account for individual differences in situational variability in the American sample, but not the Filipino sample. PMID:22146866

Turbulent MHD transport coefficients - An attempt at self-consistency

NASA Technical Reports Server (NTRS)

Chen, H.; Montgomery, D.

1987-01-01

In this paper, some multiple scale perturbation calculations of turbulent MHD transport coefficients begun in earlier papers are first completed. These generalize 'alpha effect' calculations by treating the velocity field and magnetic field on the same footing. Then the problem of rendering such calculations self-consistent is addressed, generalizing an eddy-viscosity hypothesis similar to that of Heisenberg for the Navier-Stokes case. The method also borrows from Kraichnan's direct interaction approximation. The output is a set of integral equations relating the spectra and the turbulent transport coefficients. Previous 'alpha effect' and 'beta effect' coefficients emerge as limiting cases. A treatment of the inertial range can also be given, consistent with a -5/3 energy spectrum power law. In the Navier-Stokes limit, a value of 1.72 is extracted for the Kolmogorov constant. Further applications to MHD are possible.

DFTB3: Extension of the self-consistent-charge density-functional tight-binding method (SCC-DFTB).

PubMed

Gaus, Michael; Cui, Qiang; Elstner, Marcus

2012-04-10

The self-consistent-charge density-functional tight-binding method (SCC-DFTB) is an approximate quantum chemical method derived from density functional theory (DFT) based on a second-order expansion of the DFT total energy around a reference density. In the present study we combine earlier extensions and improve them consistently with, first, an improved Coulomb interaction between atomic partial charges, and second, the complete third-order expansion of the DFT total energy. These modifications lead us to the next generation of the DFTB methodology called DFTB3, which substantially improves the description of charged systems containing elements C, H, N, O, and P, especially regarding hydrogen binding energies and proton affinities. As a result, DFTB3 is particularly applicable to biomolecular systems. Remaining challenges and possible solutions are also briefly discussed.

Epidemiological research on parent-child conflict in the United States: subgroup variations by place of birth and ethnicity, 2002-2013.

PubMed

Parra-Cardona, Jose Ruben; Yeh, Hsueh-Han; Anthony, James C

2017-01-01

Chronically escalated parent-child conflict has been observed to elicit maladaptive behavior and reduced psychological well-being in children and youth. In this epidemiological study, we sought to estimate the occurrence of escalated parent-child conflict for United States (US) adolescent subgroups defined by (a) ethnic self-identification, and (b) nativity (US-born versus foreign-born). US study populations of 12-to-17-year-olds were sampled, recruited, and assessed for the National Surveys on Drug Use and Health (NSDUH), 2002-2013 ( n  = 111, 129). Analysis-weighted contingency table analyses contrasted US-born versus foreign-born who self-identified as: (a) Hispanic, (b) non-Hispanic African-American, (c) non-Hispanic Asian, and (c) non-Hispanic White. Frequently escalated parent-child conflict was most prevalent among US-born non-Hispanic White adolescents, from 18% at age 12 (95% CI [17.6%, 18.9%]) to 29% at age 17 (95% CI [28.3%, 29.7%]), followed by US-born Hispanic and non-Hispanic Asian children. Estimated prevalence proportions were markedly lower for African-American children, from 8% at age 12 (95% CI [6.8, 8.5]) to 16% at age 17 (95% CI [14.3, 16.7]). Broad and sometimes overlapping CI indicate that larger sample sizes are needed for complete evaluation of an apparent excess occurrence of frequent parent-child conflict among US-born versus foreign-born. Nonetheless, in the larger subgroups, the US-born show a clear excess occurrence of frequent parent-child conflict. For example, US-born Mexican children have 1.7 times higher odds of experiencing frequent parent-child conflict than foreign-born Mexican children (OR = 1.7, 95% CI [1.5, 2.0], p -value < 0.001). The main discovery from this multi-ethnic sample investigation is a rank-ordering of parent-child conflict prevalence estimates from high (non-Hispanic White) to low (non-Hispanic African-American). The pattern also suggests a possibly generalizable excess associated with US-born sub-groups. The epidemiological estimates presented here merit attention in future cross-cultural research focused on parent-child conflict.

Epidemiological research on parent–child conflict in the United States: subgroup variations by place of birth and ethnicity, 2002–2013

PubMed Central

Yeh, Hsueh-Han; Anthony, James C.

2017-01-01

Background Chronically escalated parent–child conflict has been observed to elicit maladaptive behavior and reduced psychological well-being in children and youth. In this epidemiological study, we sought to estimate the occurrence of escalated parent–child conflict for United States (US) adolescent subgroups defined by (a) ethnic self-identification, and (b) nativity (US-born versus foreign-born). Methods US study populations of 12-to-17-year-olds were sampled, recruited, and assessed for the National Surveys on Drug Use and Health (NSDUH), 2002–2013 (n = 111, 129). Analysis-weighted contingency table analyses contrasted US-born versus foreign-born who self-identified as: (a) Hispanic, (b) non-Hispanic African-American, (c) non-Hispanic Asian, and (c) non-Hispanic White. Results Frequently escalated parent–child conflict was most prevalent among US-born non-Hispanic White adolescents, from 18% at age 12 (95% CI [17.6%, 18.9%]) to 29% at age 17 (95% CI [28.3%, 29.7%]), followed by US-born Hispanic and non-Hispanic Asian children. Estimated prevalence proportions were markedly lower for African-American children, from 8% at age 12 (95% CI [6.8, 8.5]) to 16% at age 17 (95% CI [14.3, 16.7]). Broad and sometimes overlapping CI indicate that larger sample sizes are needed for complete evaluation of an apparent excess occurrence of frequent parent-child conflict among US-born versus foreign-born. Nonetheless, in the larger subgroups, the US-born show a clear excess occurrence of frequent parent-child conflict. For example, US-born Mexican children have 1.7 times higher odds of experiencing frequent parent-child conflict than foreign-born Mexican children (OR = 1.7, 95% CI [1.5, 2.0], p-value < 0.001). Discussion The main discovery from this multi-ethnic sample investigation is a rank-ordering of parent-child conflict prevalence estimates from high (non-Hispanic White) to low (non-Hispanic African-American). The pattern also suggests a possibly generalizable excess associated with US-born sub-groups. The epidemiological estimates presented here merit attention in future cross-cultural research focused on parent-child conflict. PMID:28149684

Influence of beliefs about health and illness on self-care and care-seeking in foreign-born people with diabetic foot ulcers: dissimilarities related to origin.

PubMed

Hjelm, K; Apelqvist, J

2016-11-02

To describe beliefs about health and illness among foreign-born people with diabetic foot ulcers that might affect self-reported self-care and health-care seeking and to study whether there are dissimilarities related to origin. Qualitative descriptive study. Semi-structured interviews with people aged 38-86 years; 13 born in European and 13 in non-European countries (all except one in the Middle East). All resident in Sweden for 7-60 years (median: 18.5 years). Most believed foot ulcers were unavoidable and difficult to detect. Foot problems were mainly believed to be due to internal factors (diabetes), sometimes combined with external factors (inappropriate footwear, hot water, or barefoot walking). Health was described as freedom from illness and health professionals were seen as important sources of information. Perceived health deteriorated after the onset of the foot problems due to immobility and pain. People from the Middle East differed from other respondents as they discussed the importance of adapting to the will of Allah, leading to even poorer quality of life and a more negative view of future health. They also described more foot problems and perceived religion (Islam) with ritual washing of the feet to be important for health. However, they were regularly monitored to a lesser extent than European migrants. Economy affected health, more so in Europeans, due to expenses for medications and shoes. Many described limited activity in self-care, few had sought help for their problems and then solely among professionals, and had limited knowledge about the influence of glycaemic control on diabetes and foot status. Foreign-born people felt unable to prevent the incidence of foot ulcers, experienced problems with detection, and had limited knowledge of self-care. Dissimilarities in beliefs related to origin negatively influenced self-care of the feet, so it is important to assess individual beliefs and plan care and education accordingly.

Performance of Gas Scintillation Proportional Counter Array for High-Energy X-Ray Observatory

NASA Technical Reports Server (NTRS)

Gubarev, Mikhail; Ramsey, Brian; Apple, Jeffery

2004-01-01

A focal plane array of high-pressure gas scintillation proportional counters (GSPC) for a High Energy X-Ray Observatory (HERO) is developed at the Marshall Space Flight Center. The array is consisted from eight GSPCs and is a part of balloon born payload scheduled to flight in May 2004. These detectors have an active area of approximately 20 square centimeters, and are filled with a high pressure (10(exp 6) Pa) xenon-helium mixture. Imaging is via crossed-grid position-sensitive phototubes sensitive in the UV region. The performance of the GSPC is well matched to that of the telescopes x-ray optics which have response to 75 keV and a focal spot size of approximately 500 microns. The detector's energy resolution, 4% FWHM at 60 keV, is adequate for resolving the broad spectral lines of astrophysical importance and for accurate continuum measurements. Results of the on-earth detector calibration will be presented and in-flight detector performance will be provided, as available.

Internalized Homonegativity, Confucianism, and Self-Esteem at the Emergence of an LGBTQ Identity in Modern Vietnam.

PubMed

Nguyen, Tam; Angelique, Holly

2017-01-01

We examine the relationships between internalized homonegativity, Confucianism, and self-esteem among LGBTQ adults who grew up during the Open Door Policy, or Đổi Mới, in Vietnam. Participants were identified via activist networks and social media groups. They completed online survey focused on internalized homo/transphobia, self-esteem, and Confucian values. The study revealed that more exposure to Confucian values in early life is related to higher levels of internalized homonegativity. Male-born participants also had a higher level of internalized homonegativity than female-born participants. In general, lower levels of self-esteem were also related to higher levels of internalized homonegativity. We discuss the implications of these findings in light of conflicting values between Confucianism and the economic and social transformation that has occurred under Đổi Mới.

76 FR 29806 - Self-Regulatory Organizations; New York Stock Exchange LLC; Notice of Filing of Proposed Rule...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-23

... experiences with listed company peers; trading information and market data; and a series of institutional... approximately $20,000 annually, provide stock pricing data, news, institutional ownership information, research... criteria for satisfying the tiers are transparent and quantitative, and they are applied consistently to...

Approximate solution of the mode-mode coupling integral: Application to cytosine and its deuterated derivative.

PubMed

Rasheed, Tabish; Ahmad, Shabbir

2010-10-01

Ab initio Hartree-Fock (HF), density functional theory (DFT) and second-order Møller-Plesset (MP2) methods were used to perform harmonic and anharmonic calculations for the biomolecule cytosine and its deuterated derivative. The anharmonic vibrational spectra were computed using the vibrational self-consistent field (VSCF) and correlation-corrected vibrational self-consistent field (CC-VSCF) methods. Calculated anharmonic frequencies have been compared with the argon matrix spectra reported in literature. The results were analyzed with focus on the properties of anharmonic couplings between pair of modes. A simple and easy to use formula for calculation of mode-mode coupling magnitudes has been derived. The key element in present approach is the approximation that only interactions between pairs of normal modes have been taken into account, while interactions of triples or more are neglected. FTIR and Raman spectra of solid state cytosine have been recorded in the regions 400-4000 cm(-1) and 60-4000 cm(-1), respectively. Vibrational analysis and assignments are based on calculated potential energy distribution (PED) values. Copyright 2010 Elsevier B.V. All rights reserved.

Self-Consistent Field Theory of Gaussian Ring Polymers

NASA Astrophysics Data System (ADS)

Kim, Jaeup; Yang, Yong-Biao; Lee, Won Bo

2012-02-01

Ring polymers, being free from chain ends, have fundamental importance in understanding the polymer statics and dynamics which are strongly influenced by the chain end effects. At a glance, their theoretical treatment may not seem particularly difficult, but the absence of chain ends and the topological constraints make the problem non-trivial, which results in limited success in the analytical or semi-analytical formulation of ring polymer theory. Here, I present a self-consistent field theory (SCFT) formalism of Gaussian (topologically unconstrained) ring polymers for the first time. The resulting static property of homogeneous and inhomogeneous ring polymers are compared with the random phase approximation (RPA) results. The critical point for ring homopolymer system is exactly the same as the linear polymer case, χN = 2, since a critical point does not depend on local structures of polymers. The critical point for ring diblock copolymer melts is χN 17.795, which is approximately 1.7 times of that of linear diblock copolymer melts, χN 10.495. The difference is due to the ring structure constraint.

Multi-state trajectory approach to non-adiabatic dynamics: General formalism and the active state trajectory approximation

NASA Astrophysics Data System (ADS)

Tao, Guohua

2017-07-01

A general theoretical framework is derived for the recently developed multi-state trajectory (MST) approach from the time dependent Schrödinger equation, resulting in equations of motion for coupled nuclear-electronic dynamics equivalent to Hamilton dynamics or Heisenberg equation based on a new multistate Meyer-Miller (MM) model. The derived MST formalism incorporates both diabatic and adiabatic representations as limiting cases and reduces to Ehrenfest or Born-Oppenheimer dynamics in the mean-field or the single-state limits, respectively. In the general multistate formalism, nuclear dynamics is represented in terms of a set of individual state-specific trajectories, while in the active state trajectory (AST) approximation, only one single nuclear trajectory on the active state is propagated with its augmented images running on all other states. The AST approximation combines the advantages of consistent nuclear-coupled electronic dynamics in the MM model and the single nuclear trajectory in the trajectory surface hopping (TSH) treatment and therefore may provide a potential alternative to both Ehrenfest and TSH methods. The resulting algorithm features in a consistent description of coupled electronic-nuclear dynamics and excellent numerical stability. The implementation of the MST approach to several benchmark systems involving multiple nonadiabatic transitions and conical intersection shows reasonably good agreement with exact quantum calculations, and the results in both representations are similar in accuracy. The AST treatment also reproduces the exact results reasonably, sometimes even quantitatively well, with a better performance in the adiabatic representation.

Communication: Vibrational and vibronic coherences in the two dimensional spectroscopy of coupled electron-nuclear motion.

PubMed

Albert, Julian; Falge, Mirjam; Gomez, Sandra; Sola, Ignacio R; Hildenbrand, Heiko; Engel, Volker

2015-07-28

We theoretically investigate the photon-echo spectroscopy of coupled electron-nuclear quantum dynamics. Two situations are treated. In the first case, the Born-Oppenheimer (adiabatic) approximation holds. It is then possible to interpret the two-dimensional (2D) spectra in terms of vibrational motion taking place in different electronic states. In particular, pure vibrational coherences which are related to oscillations in the time-dependent third-order polarization can be identified. This concept fails in the second case, where strong non-adiabatic coupling leads to the breakdown of the Born-Oppenheimer-approximation. Then, the 2D-spectra reveal a complicated vibronic structure and vibrational coherences cannot be disentangled from the electronic motion.

Communication: Vibrational and vibronic coherences in the two dimensional spectroscopy of coupled electron-nuclear motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albert, Julian; Falge, Mirjam; Hildenbrand, Heiko

2015-07-28

We theoretically investigate the photon-echo spectroscopy of coupled electron-nuclear quantum dynamics. Two situations are treated. In the first case, the Born-Oppenheimer (adiabatic) approximation holds. It is then possible to interpret the two-dimensional (2D) spectra in terms of vibrational motion taking place in different electronic states. In particular, pure vibrational coherences which are related to oscillations in the time-dependent third-order polarization can be identified. This concept fails in the second case, where strong non-adiabatic coupling leads to the breakdown of the Born-Oppenheimer-approximation. Then, the 2D-spectra reveal a complicated vibronic structure and vibrational coherences cannot be disentangled from the electronic motion.

Dissociation of Self-Motion and Object Motion by Linear Population Decoding That Approximates Marginalization

PubMed Central

Sasaki, Ryo; Angelaki, Dora E.

2017-01-01

We use visual image motion to judge the movement of objects, as well as our own movements through the environment. Generally, image motion components caused by object motion and self-motion are confounded in the retinal image. Thus, to estimate heading, the brain would ideally marginalize out the effects of object motion (or vice versa), but little is known about how this is accomplished neurally. Behavioral studies suggest that vestibular signals play a role in dissociating object motion and self-motion, and recent computational work suggests that a linear decoder can approximate marginalization by taking advantage of diverse multisensory representations. By measuring responses of MSTd neurons in two male rhesus monkeys and by applying a recently-developed method to approximate marginalization by linear population decoding, we tested the hypothesis that vestibular signals help to dissociate self-motion and object motion. We show that vestibular signals stabilize tuning for heading in neurons with congruent visual and vestibular heading preferences, whereas they stabilize tuning for object motion in neurons with discrepant preferences. Thus, vestibular signals enhance the separability of joint tuning for object motion and self-motion. We further show that a linear decoder, designed to approximate marginalization, allows the population to represent either self-motion or object motion with good accuracy. Decoder weights are broadly consistent with a readout strategy, suggested by recent computational work, in which responses are decoded according to the vestibular preferences of multisensory neurons. These results demonstrate, at both single neuron and population levels, that vestibular signals help to dissociate self-motion and object motion. SIGNIFICANCE STATEMENT The brain often needs to estimate one property of a changing environment while ignoring others. This can be difficult because multiple properties of the environment may be confounded in sensory signals. The brain can solve this problem by marginalizing over irrelevant properties to estimate the property-of-interest. We explore this problem in the context of self-motion and object motion, which are inherently confounded in the retinal image. We examine how diversity in a population of multisensory neurons may be exploited to decode self-motion and object motion from the population activity of neurons in macaque area MSTd. PMID:29030435

Spatial Risk Assessments Based on Vector-Borne Disease Epidemiologic Data: Importance of Scale for West Nile Virus Disease in Colorado

PubMed Central

Winters, Anna M.; Eisen, Rebecca J.; Delorey, Mark J.; Fischer, Marc; Nasci, Roger S.; Zielinski-Gutierrez, Emily; Moore, Chester G.; Pape, W. John; Eisen, Lars

2010-01-01

We used epidemiologic data for human West Nile virus (WNV) disease in Colorado from 2003 and 2007 to determine 1) the degree to which estimates of vector-borne disease occurrence is influenced by spatial scale of data aggregation (county versus census tract), and 2) the extent of concordance between spatial risk patterns based on case counts versus incidence. Statistical analyses showed that county, compared with census tract, accounted for approximately 50% of the overall variance in WNV disease incidence, and approximately 33% for the subset of cases classified as West Nile neuroinvasive disease. These findings indicate that sub-county scale presentation provides valuable risk information for stakeholders. There was high concordance between spatial patterns of WNV disease incidence and case counts for census tract (83%) but not for county (50%) or zip code (31%). We discuss how these findings impact on practices to develop spatial epidemiologic data for vector-borne diseases and present data to stakeholders. PMID:20439980

Three-dimensional inversion of multisource array electromagnetic data

NASA Astrophysics Data System (ADS)

Tartaras, Efthimios

Three-dimensional (3-D) inversion is increasingly important for the correct interpretation of geophysical data sets in complex environments. To this effect, several approximate solutions have been developed that allow the construction of relatively fast inversion schemes. One such method that is fast and provides satisfactory accuracy is the quasi-linear (QL) approximation. It has, however, the drawback that it is source-dependent and, therefore, impractical in situations where multiple transmitters in different positions are employed. I have, therefore, developed a localized form of the QL approximation that is source-independent. This so-called localized quasi-linear (LQL) approximation can have a scalar, a diagonal, or a full tensor form. Numerical examples of its comparison with the full integral equation solution, the Born approximation, and the original QL approximation are given. The objective behind developing this approximation is to use it in a fast 3-D inversion scheme appropriate for multisource array data such as those collected in airborne surveys, cross-well logging, and other similar geophysical applications. I have developed such an inversion scheme using the scalar and diagonal LQL approximation. It reduces the original nonlinear inverse electromagnetic (EM) problem to three linear inverse problems. The first of these problems is solved using a weighted regularized linear conjugate gradient method, whereas the last two are solved in the least squares sense. The algorithm I developed provides the option of obtaining either smooth or focused inversion images. I have applied the 3-D LQL inversion to synthetic 3-D EM data that simulate a helicopter-borne survey over different earth models. The results demonstrate the stability and efficiency of the method and show that the LQL approximation can be a practical solution to the problem of 3-D inversion of multisource array frequency-domain EM data. I have also applied the method to helicopter-borne EM data collected by INCO Exploration over the Voisey's Bay area in Labrador, Canada. The results of the 3-D inversion successfully delineate the shallow massive sulfides and show that the method can produce reasonable results even in areas of complex geology and large resistivity contrasts.

Total Born approximation cross sections for single electron loss by atoms and ions colliding with atoms

NASA Technical Reports Server (NTRS)

Rule, D. W.

1977-01-01

The first born approximation (FBA) is applied to the calculation of single electron loss cross sections for various ions and atoms containing from one to seven electrons. Screened hydrogenic wave functions were used for the states of the electron ejected from the projectile, and Hartree-Fock elastic and incoherent scattering factors were used to describe the target. The effect of the target atom on the scaling of projectile ionization cross sections with respect to the projectile nuclear charge was explored in the case of hydrogen-like ions. Scaling of the cross section with respect to the target nuclear charge for electron loss by Fe (+25) in collision with neutral atoms ranging from H to Fe is also examined. These results were compared to those of the binary encounter approximation and to the FBA for the case of ionization by completely stripped target ions.

42 CFR 137.251. - What obligation does the retroceding Self-Governance Tribe have with respect to returning...

Code of Federal Regulations, 2014 CFR

2014-10-01

... of improvements borne by the Self-Governance Tribe in excess of $5,000 at the time of the... 42 Public Health 1 2014-10-01 2014-10-01 false What obligation does the retroceding Self... SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Retrocession § 137.251. What...

42 CFR 137.251. - What obligation does the retroceding Self-Governance Tribe have with respect to returning...

Code of Federal Regulations, 2010 CFR

2010-10-01

... of improvements borne by the Self-Governance Tribe in excess of $5,000 at the time of the... 42 Public Health 1 2010-10-01 2010-10-01 false What obligation does the retroceding Self... SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Retrocession § 137.251. What...

42 CFR 137.251. - What obligation does the retroceding Self-Governance Tribe have with respect to returning...

Code of Federal Regulations, 2013 CFR

2013-10-01

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42 CFR 137.251. - What obligation does the retroceding Self-Governance Tribe have with respect to returning...

Code of Federal Regulations, 2012 CFR

2012-10-01

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42 CFR 137.251. - What obligation does the retroceding Self-Governance Tribe have with respect to returning...

Code of Federal Regulations, 2011 CFR

2011-10-01

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Missed opportunities to prevent tuberculosis in foreign-born persons, Connecticut, 2005-2008.

PubMed

Guh, A; Sosa, L; Hadler, J L; Lobato, M N

2011-08-01

Factors that influence testing for latent tuberculosis infection (LTBI) among foreign-born persons in Connecticut are not well understood. To identify predictors for LTBI testing and challenges related to accessing health care among the foreign-born population in Connecticut. Foreign-born Connecticut residents with confirmed or suspected tuberculosis (TB) disease during June 2005-December 2008 were interviewed regarding health care access and immigration status. Predictors for self-reported testing for LTBI after US entry were determined. Of 161 foreign-born persons interviewed, 48% experienced TB disease within 5 years after arrival. One third (51/156) reported having undergone post-arrival testing for LTBI. Although those with established health care providers were more likely to have reported testing (aOR 4.49, 95%CI 1.48-13.62), only 43% of such persons were tested. Undocumented persons, the majority of whom lacked a provider (53%), were less likely than documented persons to have reported testing (aOR 0.20, 95%CI 0.06-0.67). Hispanic permanent residents (immigrants and refugees) and visitors (persons admitted temporarily) were more likely than non-Hispanics in the respective groups to have reported testing (OR 5.25, 95%CI 1.51-18.31 and OR 7.08, 95%CI 1.30-38.44, respectively). The self-reported rate of testing for LTBI among foreign-born persons in Connecticut with confirmed or suspected TB was low and differed significantly by ethnicity and immigration status. Strategies are needed to improve health care access for foreign-born persons and expand testing for LTBI, especially among non-Hispanic and undocumented populations.

Self-consistent determination of the spike-train power spectrum in a neural network with sparse connectivity.

PubMed

Dummer, Benjamin; Wieland, Stefan; Lindner, Benjamin

2014-01-01

A major source of random variability in cortical networks is the quasi-random arrival of presynaptic action potentials from many other cells. In network studies as well as in the study of the response properties of single cells embedded in a network, synaptic background input is often approximated by Poissonian spike trains. However, the output statistics of the cells is in most cases far from being Poisson. This is inconsistent with the assumption of similar spike-train statistics for pre- and postsynaptic cells in a recurrent network. Here we tackle this problem for the popular class of integrate-and-fire neurons and study a self-consistent statistics of input and output spectra of neural spike trains. Instead of actually using a large network, we use an iterative scheme, in which we simulate a single neuron over several generations. In each of these generations, the neuron is stimulated with surrogate stochastic input that has a similar statistics as the output of the previous generation. For the surrogate input, we employ two distinct approximations: (i) a superposition of renewal spike trains with the same interspike interval density as observed in the previous generation and (ii) a Gaussian current with a power spectrum proportional to that observed in the previous generation. For input parameters that correspond to balanced input in the network, both the renewal and the Gaussian iteration procedure converge quickly and yield comparable results for the self-consistent spike-train power spectrum. We compare our results to large-scale simulations of a random sparsely connected network of leaky integrate-and-fire neurons (Brunel, 2000) and show that in the asynchronous regime close to a state of balanced synaptic input from the network, our iterative schemes provide an excellent approximations to the autocorrelation of spike trains in the recurrent network.

Energy conserving, linear scaling Born-Oppenheimer molecular dynamics.

PubMed

Cawkwell, M J; Niklasson, Anders M N

2012-10-07

Born-Oppenheimer molecular dynamics simulations with long-term conservation of the total energy and a computational cost that scales linearly with system size have been obtained simultaneously. Linear scaling with a low pre-factor is achieved using density matrix purification with sparse matrix algebra and a numerical threshold on matrix elements. The extended Lagrangian Born-Oppenheimer molecular dynamics formalism [A. M. N. Niklasson, Phys. Rev. Lett. 100, 123004 (2008)] yields microcanonical trajectories with the approximate forces obtained from the linear scaling method that exhibit no systematic drift over hundreds of picoseconds and which are indistinguishable from trajectories computed using exact forces.

Self-consistent calculations for the electronic structure of a vacancy in copper. A solution of the embedding problem

NASA Astrophysics Data System (ADS)

Zeller, R.; Braspenning, P. J.

1982-06-01

The charge density and the local density of states for a vacancy in Cu and for the first shell of Cu neighbours are calculated by the KKR-Green's function technique. The muffin-tin potentials for the vacancy and the neighbour shell atoms are determined self-consistently in the local density approximation of density functional theory. By the use of the proper host Green's function the embedding of this cluster of 13 perturbed muffin-tins into the infinite array of bulk Cu muffin-tin potentials is described rigorously, thus representing a solution of the embedding problem. The calculations demonstrate a rather large charge transfer of 1.1 electrons from the first neighbour shell to the vacancy.

Immigrants from Mexico experience serious behavioral and psychiatric problems at far lower rates than US-born Americans.

PubMed

Salas-Wright, Christopher P; Vaughn, Michael G; Goings, Trenette Clark

2017-10-01

To examine the prevalence of self-reported criminal and violent behavior, substance use disorders, and mental disorders among Mexican immigrants vis-à-vis the US born. Study findings are based on national data collected between 2012 and 2013. Binomial logistic regression was employed to examine the relationship between immigrant status and behavioral/psychiatric outcomes. Mexican immigrants report substantially lower levels of criminal and violent behaviors, substance use disorders, and mental disorders compared to US-born individuals. While some immigrants from Mexico have serious behavioral and psychiatric problems, Mexican immigrants in general experience such problems at far lower rates than US-born individuals.

Adjustment of Children Born to Teenage Mothers: The Contribution of Risk and Protective Factors.

ERIC Educational Resources Information Center

Dubow, Eric F.; Luster, Tom

1990-01-01

Examined contribution of risk and protective factors in adjustment of 721 children, age 8-15, born to teenage mothers. Results showed that exposure to increasing number of risk factors (poverty, urban residence, mother's self-esteem) was associated with greater vulnerability to adjustment problems, while protective factors (intelligence,…

Multireference Density Functional Theory with Generalized Auxiliary Systems for Ground and Excited States.

PubMed

Chen, Zehua; Zhang, Du; Jin, Ye; Yang, Yang; Su, Neil Qiang; Yang, Weitao

2017-09-21

To describe static correlation, we develop a new approach to density functional theory (DFT), which uses a generalized auxiliary system that is of a different symmetry, such as particle number or spin, from that of the physical system. The total energy of the physical system consists of two parts: the energy of the auxiliary system, which is determined with a chosen density functional approximation (DFA), and the excitation energy from an approximate linear response theory that restores the symmetry to that of the physical system, thus rigorously leading to a multideterminant description of the physical system. The electron density of the physical system is different from that of the auxiliary system and is uniquely determined from the functional derivative of the total energy with respect to the external potential. Our energy functional is thus an implicit functional of the physical system density, but an explicit functional of the auxiliary system density. We show that the total energy minimum and stationary states, describing the ground and excited states of the physical system, can be obtained by a self-consistent optimization with respect to the explicit variable, the generalized Kohn-Sham noninteracting density matrix. We have developed the generalized optimized effective potential method for the self-consistent optimization. Among options of the auxiliary system and the associated linear response theory, reformulated versions of the particle-particle random phase approximation (pp-RPA) and the spin-flip time-dependent density functional theory (SF-TDDFT) are selected for illustration of principle. Numerical results show that our multireference DFT successfully describes static correlation in bond dissociation and double bond rotation.

Intelligence and psychosocial functioning during long-term growth hormone therapy in children born small for gestational age.

PubMed

van Pareren, Yvonne K; Duivenvoorden, Hugo J; Slijper, Froukje S M; Koot, Hans M; Hokken-Koelega, Anita C S

2004-11-01

Short stature is not the only problem faced by small for gestational age (SGA) children. Being born SGA has also been associated with lowered intelligence, poor academic performance, low social competence, and behavioral problems. Although GH treatment in short children born SGA can result in a normalization of height during childhood, the effect of GH treatment on intelligence and psychosocial functioning remains to be investigated. We show the longitudinal results of a randomized, double-blind, GH-dose response study initiated in 1991 to follow growth, intelligence quotient (IQ), and psychosocial functioning in SGA children during long-term GH treatment. Patients were assigned to one of two treatment groups (1 or 2 mg GH/m(2) body surface.d, or approximately 0.035 or 0.07 mg/kg.d). Intelligence and psychosocial functioning were evaluated at start of GH treatment (n = 74), after 2 yr of GH treatment (n = 76), and in 2001 (n = 53). IQ was assessed by a short-form Wechsler Intelligence Scale for Children-Revised or Wechsler Adult Intelligence Scale (Block-design and Vocabulary subtests). Behavioral problems were measured by the Achenbach Child Behavior Checklist or Young Adult Behavior Checklist, and self-perception was measured by the Harter Self-Perception Profile. Mean (sem) birth length sd score was -3.6 (0.2), mean age and height at start was 7.4 (0.2) yr and -3.0 (0.1) sd score, respectively, mean duration of GH treatment was 8.0 (0.2) yr, and mean age in 2001 was 16.5 (0.3) yr. After 2 yr of GH treatment, 96% of both GH groups showed a height gain sd score of 1 sd from the start of treatment or more, resulting in a normal height (i.e. height >/= -2.0 sd for age and sex) in 70% of the children. In 2001, 48 (91%) of the 53 children participating in this study had reached a normal height. Block-design s-score and the estimated total IQ significantly increased (P < 0.001 and P < 0.001, respectively) from scores significantly lower than Dutch peers at start (P < 0.001 and P < 0.001, respectively) to comparable scores in 2001. The increase over time for the Vocabulary s-score was not significant. Internalizing Behavior sd scores remained comparable to Dutch peers, whereas Externalizing Behavior sd scores and Total Problem Behavior sd scores improved significantly during GH therapy (P < 0.01 and P < 0.05, respectively) to scores comparable to Dutch peers. Self-perception sd scores improved from start of GH treatment until 2001 (P < 0.001) to scores significantly higher than Dutch peers (P < 0.05). No significant differences between the two GH dosage groups were found. Improvement in Externalizing and Total Problem Behavior sd scores over time was significantly related to change in height sd score (P < 0.05 and P < 0.01, respectively), whereas scores over time for Vocabulary, Block-design, Internalizing, or total Harter Self-Perception score were not related to change in height sd scores. In conclusion, parallel to a GH-induced catch-up growth in adolescents born SGA, IQ, behavior, and self-perception showed a significant improvement over time from scores below average to scores comparable to Dutch peers. In addition, children whose height over time became closer to that of their peers showed less problem behavior.

Electronic structure and magneto-optical effects in CeSb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liechtenstein, A.I.; Antropov, V.P.; Harmon, B.N.

1994-04-15

The electronic structure and magneto-optical spectra of CeSb have been calculated using the self-consistent local-density approximation with explicit on-site Coulomb parameters for the correlated [ital f] state of cerium. The essential electronic structure of cerium antimonide consists of one occupied [ital f] band, predominantly with orbital [ital m]=[minus]3 character and spin [sigma]=1 located 2 eV below the Fermi level and interacting with broad Sb [ital p] bands crossing [ital E][sub [ital F

Quantum Theories of Self-Localization

NASA Astrophysics Data System (ADS)

Bernstein, Lisa Joan

In the classical dynamics of coupled oscillator systems, nonlinearity leads to the existence of stable solutions in which energy remains localized for all time. Here the quantum-mechanical counterpart of classical self-localization is investigated in the context of two model systems. For these quantum models, the terms corresponding to classical nonlinearities modify a subset of the stationary quantum states to be particularly suited to the creation of nonstationary wavepackets that localize energy for long times. The first model considered here is the Quantized Discrete Self-Trapping model (QDST), a system of anharmonic oscillators with linear dispersive coupling used to model local modes of vibration in polyatomic molecules. A simple formula is derived for a particular symmetry class of QDST systems which gives an analytic connection between quantum self-localization and classical local modes. This formula is also shown to be useful in the interpretation of the vibrational spectra of some molecules. The second model studied is the Frohlich/Einstein Dimer (FED), a two-site system of anharmonically coupled oscillators based on the Frohlich Hamiltonian and motivated by the theory of Davydov solitons in biological protein. The Born-Oppenheimer perturbation method is used to obtain approximate stationary state wavefunctions with error estimates for the FED at the first excited level. A second approach is used to reduce the first excited level FED eigenvalue problem to a system of ordinary differential equations. A simple theory of low-energy self-localization in the FED is discussed. The quantum theories of self-localization in the intrinsic QDST model and the extrinsic FED model are compared.

A Stochastic Tick-Borne Disease Model: Exploring the Probability of Pathogen Persistence.

PubMed

Maliyoni, Milliward; Chirove, Faraimunashe; Gaff, Holly D; Govinder, Keshlan S

2017-09-01

We formulate and analyse a stochastic epidemic model for the transmission dynamics of a tick-borne disease in a single population using a continuous-time Markov chain approach. The stochastic model is based on an existing deterministic metapopulation tick-borne disease model. We compare the disease dynamics of the deterministic and stochastic models in order to determine the effect of randomness in tick-borne disease dynamics. The probability of disease extinction and that of a major outbreak are computed and approximated using the multitype Galton-Watson branching process and numerical simulations, respectively. Analytical and numerical results show some significant differences in model predictions between the stochastic and deterministic models. In particular, we find that a disease outbreak is more likely if the disease is introduced by infected deer as opposed to infected ticks. These insights demonstrate the importance of host movement in the expansion of tick-borne diseases into new geographic areas.

Phenomenological Study of Interaction between Solar Acoustic Waves and Sunspots from Measured Scattered Wavefunctions

NASA Astrophysics Data System (ADS)

Yang, Ming-Hsu; Chou, Dean-Yi; Zhao, Hui; Liang, Zhi-Chao

2012-08-01

The solar acoustic waves around a sunspot are modified because of the interaction with the sunspot. The interaction can be viewed as that the sunspot, excited by the incident wave, generates the scattered wave, and the scattered wave is added to the incident wave to form the total wave around the sunspot. We define an interaction parameter, which could be complex, describing the interaction between the acoustic waves and the sunspot. The scattered wavefunction on the surface can be expressed as a two-dimensional integral of the product of the Green's function, the wavefunction, and the two-dimensional interaction parameter over the sunspot area for the Born approximation of different orders. We assume a simple model for the two-dimensional interaction parameter distribution: its absolute value is axisymmetric with a Gaussian distribution and its phase is a constant. The measured scattered wavefunctions of various modes for NOAAs 11084 and 11092 are fitted to the theoretical scattered wavefunctions to determine the three model parameters, magnitude, Gaussian radius, and phase, for the Born approximation of different orders. The three model parameters converge to some values at high-order Born approximations. The result of the first-order Born approximation is significantly different from the convergent value in some cases. The rate of convergence depends on the sunspot size and wavelength. It converges more rapidly for the smaller sunspot and longer wavelength. The magnitude increases with mode frequency and degree for each radial order. The Gaussian radius is insensitive to frequency and degree. The spatial range of the interaction parameter is greater than that of the continuum intensity deficit, but smaller than that of the acoustic power deficit of the sunspot. The phase versus phase speed falls into a small range. This suggests that the phase could be a function phase speed. NOAAs 11084 and 11092 have a similar magnitude and phase, although the ratio of their sizes is 0.75.

Surface charge conductivity of a topological insulator in a magnetic field: The effect of hexagonal warping

NASA Astrophysics Data System (ADS)

Akzyanov, R. S.; Rakhmanov, A. L.

2018-02-01

We investigate the influence of hexagonal warping on the transport properties of topological insulators. We study the charge conductivity within Kubo formalism in the first Born approximation using low-energy expansion of the Hamiltonian near the Dirac point. The effects of disorder, magnetic field, and chemical-potential value are analyzed in detail. We find that the presence of hexagonal warping significantly affects the conductivity of the topological insulator. In particular, it gives rise to the growth of the longitudinal conductivity with the increase of the disorder and anisotropic anomalous in-plane magnetoresistance. Hexagonal warping also affects the quantum anomalous Hall effect and anomalous out-of-plane magnetoresistance. The obtained results are consistent with the experimental data.

Bluues: a program for the analysis of the electrostatic properties of proteins based on generalized Born radii

PubMed Central

2012-01-01

Background The Poisson-Boltzmann (PB) equation and its linear approximation have been widely used to describe biomolecular electrostatics. Generalized Born (GB) models offer a convenient computational approximation for the more fundamental approach based on the Poisson-Boltzmann equation, and allows estimation of pairwise contributions to electrostatic effects in the molecular context. Results We have implemented in a single program most common analyses of the electrostatic properties of proteins. The program first computes generalized Born radii, via a surface integral and then it uses generalized Born radii (using a finite radius test particle) to perform electrostic analyses. In particular the ouput of the program entails, depending on user's requirement: 1) the generalized Born radius of each atom; 2) the electrostatic solvation free energy; 3) the electrostatic forces on each atom (currently in a dvelopmental stage); 4) the pH-dependent properties (total charge and pH-dependent free energy of folding in the pH range -2 to 18; 5) the pKa of all ionizable groups; 6) the electrostatic potential at the surface of the molecule; 7) the electrostatic potential in a volume surrounding the molecule; Conclusions Although at the expense of limited flexibility the program provides most common analyses with requirement of a single input file in PQR format. The results obtained are comparable to those obtained using state-of-the-art Poisson-Boltzmann solvers. A Linux executable with example input and output files is provided as supplementary material. PMID:22536964

Interpretation of ES, CS, and IOS approximations within a translational--internal coupling scheme. IV. ES and IOS molecule--molecule cross sections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snider, R.F.; Parvatiyar, M.G.

1981-05-15

Properties of energy sudden and infinite order sudden translational--internal reduced S matrices are given for general molecule--molecule collisions. Formal similarities with the distorted wave Born approximation are discussed. Structural simplifications of energy dependent and kinetic cross sections associated with making the ES approximation are described. Conceptual difficulties associated with applying the ES and IOS approximations to kinetic processes dominated by energetically inelastic collisions are pointed out.

Health-related quality of life and health behaviors in a population-based sample of older, foreign-born, Chinese American adults living in New York City.

PubMed

Wyatt, Laura C; Trinh-Shevrin, Chau; Islam, Nadia S; Kwon, Simona C

2014-10-01

Although the New York City Chinese population aged ≥ 65 years increased by 50% between 2000 and 2010, the health needs of this population are poorly understood. Approximately 3,001 Chinese individuals from high-density Asian American New York City areas were included in the REACH U.S. Risk Factor Survey; 805 (26.8%) were aged ≥ 65 years and foreign-born. Four health-related quality of life and three behavioral risk factor outcome variables were examined. Descriptive statistics were conducted by gender, and logistic regression models assessed sociodemographic and health factors associated with each outcome. Few women were current smokers (1.3% vs. 14.8% of men), 19% of respondents ate fruits and vegetables more than or equal to five times daily, and one-third of individuals received sufficient weekly physical activity. Days of poor health were similar to the national population aged ≥ 65 years, while self-reported fair or poor health was much greater among our Chinese sample; over 60% of respondents rated their health as fair or poor. Lower education and lower obesity were significantly associated with cigarette smoking among men, and older age was significantly associated with insufficient physical activity overall. Female gender was significantly associated with all poor health days; older age was significantly associated with poor days of physical health, and lower income was significantly associated with poor days of physical health and fair or poor self-reported health. This study provides important health-related information on a rapidly growing older population and highlights future research areas to inform culturally appropriate health promotion and disease prevention strategies and policies within community-based settings. © 2014 Society for Public Health Education.

High Energy Replicated Optics to Explore the Sun Balloon-Borne Telescope: Astrophysical Pointing

NASA Technical Reports Server (NTRS)

Gaskin, Jessica; Wilson-Hodge, Colleen; Ramsey, Brian; Apple, Jeff; Kurt, Dietz; Tennant, Allyn; Swartz, Douglas; Christe, Steven D.; Shih, Albert

2014-01-01

On September 21, 2013, the High Energy Replicated Optics to Explore the Sun, or HEROES, balloon-borne x-ray telescope launched from the Columbia Scientific Balloon Facility's site in Ft. Summer, NM. The flight lasted for approximately 27 hours and the observational targets included the Sun and astrophysical sources GRS 1915+105 and the Crab Nebula. Over the past year, the HEROES team upgraded the existing High Energy Replicated Optics (HERO) balloon-borne telescope to make unique scientific measurements of the Sun and astrophysical targets during the same flight. The HEROES Project is a multi-NASA Center effort with team members at both Marshall Space Flight Center (MSFC) and Goddard Space Flight Center (GSFC), and is led by Co-PIs (one at each Center). The HEROES payload consists of the hard X-ray telescope HERO, developed at MSFC, combined with several new systems. To allow the HEROES telescope to make observations of the Sun, a new solar aspect system was added to supplement the existing star camera for fine pointing during both the day and night. A mechanical shutter was added to the star camera to protect it during solar observations and two alignment monitoring systems were added for improved pointing and post-flight data reconstruction. This mission was funded by the NASA HOPE (Hands-On Project Experience) Training Opportunity awarded by the NASA Academy of Program/Project and Engineering Leadership, in partnership with NASA's Science Mission Directorate, Office of the Chief Engineer and Office of the Chief Technologist.

Mechanisms of double-strand-break repair during gene targeting in mammalian cells.

PubMed Central

Ng, P; Baker, M D

1999-01-01

In the present study, the mechanism of double-strand-break (DSB) repair during gene targeting at the chromosomal immunoglobulin mu-locus in a murine hybridoma was examined. The gene-targeting assay utilized specially designed insertion vectors genetically marked in the region of homology to the chromosomal mu-locus by six diagnostic restriction enzyme site markers. The restriction enzyme markers permitted the contribution of vector-borne and chromosomal mu-sequences in the recombinant product to be determined. The use of the insertion vectors in conjunction with a plating procedure in which individual integrative homologous recombination events were retained for analysis revealed several important features about the mammalian DSB repair process:The presence of the markers within the region of shared homology did not affect the efficiency of gene targeting.In the majority of recombinants, the vector-borne marker proximal to the DSB was absent, being replaced with the corresponding chromosomal restriction enzyme site. This result is consistent with either formation and repair of a vector-borne gap or an "end" bias in mismatch repair of heteroduplex DNA (hDNA) that favored the chromosomal sequence. Formation of hDNA was frequently associated with gene targeting and, in most cases, began approximately 645 bp from the DSB and could encompass a distance of at least 1469 bp.The hDNA was efficiently repaired prior to DNA replication.The repair of adjacent mismatches in hDNA occurred predominantly on the same strand, suggesting the involvement of a long-patch repair mechanism. PMID:10049929

A rational explanation of wave-particle duality of light

NASA Astrophysics Data System (ADS)

Rashkovskiy, S. A.

2013-10-01

The wave-particle duality is a fundamental property of the nature. At the same time, it is one of the greatest mysteries of modern physics. This gave rise to a whole direction in quantum physics - the interpretation of quantum mechanics. The Wiener experiments demonstrating the wave-particle duality of light are discussed. It is shown that almost all interpretations of quantum mechanics allow explaining the double-slit experiments, but are powerless to explain the Wiener experiments. The reason of the paradox, associated with the wave-particle duality is analyzed. The quantum theory consists of two independent parts: (i) the dynamic equations describing the behavior of a quantum object (for example, the Schrodinger or Maxwell equations), and (ii) the Born's rule, the relation between the wave function and the probability of finding the particle at a given point. It is shown that precisely the Born's rule results in paradox in explaining the wave-particle duality. In order to eliminate this paradox, we propose a new rational interpretation of the wave-particle duality and associated new rule, connecting the corpuscular and wave properties of quantum objects. It is shown that this new rational interpretation of the wave-particle duality allows using the classic images of particle and wave in explaining the quantum mechanical and optical phenomena, does not result in paradox in explaining the doubleslit experiments and Wiener experiments, and does not contradict to the modern quantum mechanical concepts. It is shown that the Born's rule follows immediately from proposed new rules as an approximation.

Birth Order and Injury-Related Infant Mortality in the U.S.

PubMed

Ahrens, Katherine A; Rossen, Lauren M; Thoma, Marie E; Warner, Margaret; Simon, Alan E

2017-10-01

The purpose of this study was to evaluate the risk of death during the first year of life due to injury, such as unintentional injury and homicide, by birth order in the U.S. Using national birth cohort-linked birth-infant death data (births, 2000-2010; deaths, 2000-2011), risks of infant mortality due to injury in second-, third-, fourth-, and fifth or later-born singleton infants were compared with first-born singleton infants. Risk ratios were estimated using log-binomial models adjusted for maternal age, marital status, race/ethnicity, and education. The statistical analyses were conducted in 2016. Approximately 40%, 32%, 16%, 7%, and 4% of singleton live births were first, second, third, fourth, and fifth or later born, respectively. From 2000 to 2011, a total of 15,866 infants died as a result of injury (approximately 1,442 deaths per year). Compared with first-born infants (2.9 deaths per 10,000 live births), second or later-born infants were at increased risk of infant mortality due to injury (second, 3.6 deaths; third, 4.2 deaths; fourth, 4.8 deaths; fifth or later, 6.4 deaths). The corresponding adjusted risk ratios were as follows: second, 1.84 (95% CI=1.76, 1.91); third, 2.42 (95% CI=2.30, 2.54); fourth, 2.96 (95% CI=2.77, 3.16); and fifth or later, 4.26 (95% CI=3.96, 4.57). Singleton infants born second or later were at increased risk of mortality due to injury during their first year of life in the U.S. This study's findings highlight the importance of investigating underlying mechanisms behind this increased risk. Published by Elsevier Inc.

Self-consistent pseudopotential calculation of the bulk properties of Mo and W

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zunger, A.; Cohen, M.L.

The bulk properties of Mo and W are calculated using the recently developed momentum-space approach for calculating total energy via a nonlocal pseudopotential. This approach avoids any shape approximation to the variational charge density (e.g., muffin tins), is fully self-consistent, and replaces the multidimensional and multicenter integrals akin to real-space representations by simple and readily convergent reciprocal-space lattice sums. We use first-principles atomic pseudopotentials which have been previously demonstrated to yield band structures and charge densities for both semiconductors and transition metals in good agreement with experiment and all-electron calculations. Using a mixed-basis representation for the crystalline wave function, wemore » are able to accurately reproduce both the localized and itinerant features of the electronic states in these systems. These first-principles pseudopotentials, together with the self-consistent density-functional representation for both the exchange and the correlation screening, yields agreement with experiment of 0.2% in the lattice parameters, 2% and 11% for the binding energies of Mo and W, respectively, and 12% and 7% for the bulk moduli of Mo and W, respectively.« less

Electric dipole strength and dipole polarizability in 48Ca within a fully self-consistent second random-phase approximation

NASA Astrophysics Data System (ADS)

Gambacurta, D.; Grasso, M.; Vasseur, O.

2018-02-01

The second random-phase-approximation model corrected by a subtraction procedure designed to cure double counting, instabilities, and ultraviolet divergences, is employed for the first time to analyze the dipole strength and polarizability in 48Ca. All the terms of the residual interaction are included, leading to a fully self-consistent scheme. Results are illustrated with two Skyrme parametrizations, SGII and SLy4. Those obtained with the SGII interaction are particularly satisfactory. In this case, the low-lying strength below the neutron threshold is well reproduced and the giant dipole resonance is described in a very satisfactory way especially in its spreading and fragmentation. Spreading and fragmentation are produced in a natural way within such a theoretical model by the coupling of 1 particle-1 hole and 2 particle-2 hole configurations. Owing to this feature, we may provide for the electric polarizability as a function of the excitation energy a curve with a similar slope around the centroid energy of the giant resonance compared to the corresponding experimental results. This represents a considerable improvement with respect to previous theoretical predictions obtained with the random-phase approximation or with several ab-initio models. In such cases, the spreading width of the excitation cannot be reproduced and the polarizability as a function of the excitation energy displays a stiff increase around the predicted centroid energy of the giant resonance.

Anharmonic phonons and second-order phase-transitions by the stochastic self-consistent harmonic approximation

NASA Astrophysics Data System (ADS)

Mauri, Francesco

Anharmonic effects can generally be treated within perturbation theory. Such an approach breaks down when the harmonic solution is dynamically unstable or when the anharmonic corrections of the phonon energies are larger than the harmonic frequencies themselves. This situation occurs near lattice-related second-order phase-transitions such as charge-density-wave (CDW) or ferroelectric instabilities or in H-containing materials, where the large zero-point motion of the protons results in a violation of the harmonic approximation. Interestingly, even in these cases, phonons can be observed, measured, and used to model transport properties. In order to treat such cases, we developed a stochastic implementation of the self-consistent harmonic approximation valid to treat anharmonicity in the nonperturbative regime and to obtain, from first-principles, the structural, thermodynamic and vibrational properties of strongly anharmonic systems. I will present applications to the ferroelectric transitions in SnTe, to the CWD transitions in NbS2 and NbSe2 (in bulk and monolayer) and to the hydrogen-bond symmetrization transition in the superconducting hydrogen sulfide system, that exhibits the highest Tc reported for any superconductor so far. In all cases we are able to predict the transition temperature (pressure) and the evolution of phonons with temperature (pressure). This project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant agreement No. 696656 GrapheneCore1.

South Asian populations in Canada: migration and mental health

PubMed Central

2014-01-01

Background South Asian populations are the largest visible minority group in Canada; however, there is very little information on the mental health of these populations. The objective of this study was to determine the prevalence rates and characteristics of mental health outcomes for South Asian first-generation immigrant and second-generation Canadian-born populations. Methods The Canadian Community Health Survey (CCHS) 2011 was used to calculate the estimated prevalence rates of the following mental health outcomes: mood disorders, anxiety disorders, fair-poor self-perceived mental health status, and extremely stressful life stress. The characteristics associated with these four mental health outcomes were determined through multivariate logistic regression analysis of merged CCHS 2007–2011 data. Results South Asian Canadian-born (3.5%, 95% CI 3.4-3.6%) and South Asian immigrant populations (3.5%, 95% CI 3.5-3.5%) did not vary significantly in estimated prevalence rates of mood disorders. However, South Asian immigrants experienced higher estimated prevalence rates of diagnosed anxiety disorders (3.4%, 95% CI 3.4-3.5 vs. 1.1%, 95% CI 1.1-1.1%) and self-reported extremely stressful life stress (2.6%, 95% CI 2.6-2.7% vs. 2.4%, 95% CI 2.3-2.4%) compared to their Canadian-born counterparts. Lastly, South Asian Canadian-born populations had a higher estimated prevalence rate of poor-fair self-perceived mental health status (4.4%, 95% CI 4.3-4.5%) compared to their immigrant counterparts (3.4%, 95% CI 3.3-3.4%). Different profiles of mental health determinants emerged for South Asian Canadian-born and immigrant populations. Female gender, having no children under the age of 12 in the household, food insecurity, poor-fair self-rated health status, being a current smoker, immigrating to Canada before adulthood, and taking the CCHS survey in either English or French was associated with greater risk of negative mental health outcomes for South Asian immigrant populations, while not being currently employed, having a regular medical doctor, and inactive physical activity level were associated with greater risk for South Asian Canadian-born populations. Conclusions Mental health outreach programs need to be cognizant of the differences in prevalence rates and characteristics of mental health outcomes for South Asian immigrant and Canadian-born populations to better tailor mental health services to be responsive to the unique mental health needs of South Asian populations in Canada. PMID:24884792

On basis set superposition error corrected stabilization energies for large n-body clusters.

PubMed

Walczak, Katarzyna; Friedrich, Joachim; Dolg, Michael

2011-10-07

In this contribution, we propose an approximate basis set superposition error (BSSE) correction scheme for the site-site function counterpoise and for the Valiron-Mayer function counterpoise correction of second order to account for the basis set superposition error in clusters with a large number of subunits. The accuracy of the proposed scheme has been investigated for a water cluster series at the CCSD(T), CCSD, MP2, and self-consistent field levels of theory using Dunning's correlation consistent basis sets. The BSSE corrected stabilization energies for a series of water clusters are presented. A study regarding the possible savings with respect to computational resources has been carried out as well as a monitoring of the basis set dependence of the approximate BSSE corrections. © 2011 American Institute of Physics

On the emergence of the structure of physics

NASA Astrophysics Data System (ADS)

Majid, S.

2018-04-01

We consider Hilbert's problem of the axioms of physics at a qualitative or conceptual level. This is more pressing than ever as we seek to understand how both general relativity and quantum theory could emerge from some deeper theory of quantum gravity, and in this regard I have previously proposed a principle of self-duality or quantum Born reciprocity as a key structure. Here, I outline some of my recent work around the idea of quantum space-time as motivated by this non-standard philosophy, including a new toy model of gravity on a space-time consisting of four points forming a square. This article is part of the theme issue `Hilbert's sixth problem'.

On the emergence of the structure of physics.

PubMed

Majid, S

2018-04-28

We consider Hilbert's problem of the axioms of physics at a qualitative or conceptual level. This is more pressing than ever as we seek to understand how both general relativity and quantum theory could emerge from some deeper theory of quantum gravity, and in this regard I have previously proposed a principle of self-duality or quantum Born reciprocity as a key structure. Here, I outline some of my recent work around the idea of quantum space-time as motivated by this non-standard philosophy, including a new toy model of gravity on a space-time consisting of four points forming a square.This article is part of the theme issue 'Hilbert's sixth problem'. © 2018 The Author(s).

Eusebio Vela's Mexican Hagiographies: Self-Fashioning in Eighteenth-Century Theater

ERIC Educational Resources Information Center

Post, Ben

2016-01-01

Eighteenth-century actor and playwright Eusebio Vela, long thought to be born in Mexico but actually born in Spain, dominated Mexico City's Coliseo theater for decades and has been variously interpreted as a creole patriot or as a Spanish propagandist. Vela's four extant plays, which treat the fall of Spain, Telemachus's wanderings in the…

"Born Frees", Negotiating the Terrain towards Selfhood and Wellness: A Life Orientation Perspective

ERIC Educational Resources Information Center

Magano, Meahabo Dinah; Berman, Ashley Ita

2016-01-01

This study was contextualised within the Life Orientation subject of "Self in Society". It acknowledges that the present time is uniquely significant in South African history as the generation of youth leaving school are now considered "born frees". This generation is considered to be free from the first-hand trauma that was…

Social Experience Does Not Abolish Cultural Diversity in Eye Movements

PubMed Central

Kelly, David J.; Jack, Rachael E.; Miellet, Sébastien; De Luca, Emanuele; Foreman, Kay; Caldara, Roberto

2011-01-01

Adults from Eastern (e.g., China) and Western (e.g., USA) cultural groups display pronounced differences in a range of visual processing tasks. For example, the eye movement strategies used for information extraction during a variety of face processing tasks (e.g., identification and facial expressions of emotion categorization) differs across cultural groups. Currently, many of the differences reported in previous studies have asserted that culture itself is responsible for shaping the way we process visual information, yet this has never been directly investigated. In the current study, we assessed the relative contribution of genetic and cultural factors by testing face processing in a population of British Born Chinese adults using face recognition and expression classification tasks. Contrary to predictions made by the cultural differences framework, the majority of British Born Chinese adults deployed “Eastern” eye movement strategies, while approximately 25% of participants displayed “Western” strategies. Furthermore, the cultural eye movement strategies used by individuals were consistent across recognition and expression tasks. These findings suggest that “culture” alone cannot straightforwardly account for diversity in eye movement patterns. Instead a more complex understanding of how the environment and individual experiences can influence the mechanisms that govern visual processing is required. PMID:21886626

Vacuum birefringence in strong magnetic fields: (II) Complex refractive index from the lowest Landau level

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hattori, Koichi, E-mail: khattori@yonsei.ac.kr; Itakura, Kazunori, E-mail: kazunori.itakura@kek.jp; Department of Particle and Nuclear Studies, Graduate University for Advanced Studies

2013-07-15

We compute the refractive indices of a photon propagating in strong magnetic fields on the basis of the analytic representation of the vacuum polarization tensor obtained in our previous paper. When the external magnetic field is strong enough for the fermion one-loop diagram of the polarization tensor to be approximated by the lowest Landau level, the propagating mode in parallel to the magnetic field is subject to modification: The refractive index deviates from unity and can be very large, and when the photon energy is large enough, the refractive index acquires an imaginary part indicating decay of a photon intomore » a fermion–antifermion pair. We study dependences of the refractive index on the propagating angle and the magnetic-field strength. It is also emphasized that a self-consistent treatment of the equation which defines the refractive index is indispensable for accurate description of the refractive index. This self-consistent treatment physically corresponds to consistently including the effects of back reactions of the distorted Dirac sea in response to the incident photon. -- Highlights: •Vacuum birefringence and photon decay are described by the complex refractive index. •Resummed photon vacuum polarization tensor in the lowest Landau level is used. •Back reactions from the distorted Dirac sea are self-consistently taken into account. •Self-consistent treatment drastically changes structure in photon energy dependence. •Dependences on photon propagation angle and magnetic-field strength are presented.« less

Strong-potential Born calculations for electron capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGuire, J.H.; Sil, N.C.

1983-12-01

A closed-form expression for 1s-1s electron capture has been developed in the strong-potential Born (SPB) approximation. Terms of the order (Z/sub p//v)/sup 2/ are ignored in our expression, where Z/sub p/ is the charge of the projectile and v is the collision velocity. Our errors of order (Z/sub p//v)/sup 2/ are within the accuracy of the SPB approximation itself, which is valid to first order in the projectile-electron interaction V/sub p/ (and all orders in the stronger target potential V/sub T/). Calculations using our expression are in better agreement with experimental observations of the shape of the Thomas peak thanmore » are other calculations.« less

Electromagnetic backscattering from a random distribution of lossy dielectric scatterers

NASA Technical Reports Server (NTRS)

Lang, R. H.

1980-01-01

Electromagnetic backscattering from a sparse distribution of discrete lossy dielectric scatterers occupying a region 5 was studied. The scatterers are assumed to have random position and orientation. Scattered fields are calculated by first finding the mean field and then by using it to define an equivalent medium within the volume 5. The scatterers are then viewed as being embedded in the equivalent medium; the distorted Born approximation is then used to find the scattered fields. This technique represents an improvement over the standard Born approximation since it takes into account the attenuation of the incident and scattered waves in the equivalent medium. The method is used to model a leaf canopy when the leaves are modeled by lossy dielectric discs.

Emerging self-regulation in toddlers born preterm or low birth weight: Differential susceptibility to parenting?

PubMed Central

POEHLMANN, JULIE; SCHWICHTENBERG, A. J. M.; SHLAFER, REBECCA J.; HAHN, EMILY; BIANCHI, JON-PAUL; WARNER, RACHAEL

2012-01-01

The differential susceptibility to parenting model was examined in relation to toddler self-regulation in a prospective longitudinal study of infants born preterm or low birth weight. We followed 153 mother–infant dyads across five time points between the infant’s Neonatal Intensive Care Unit stay and 24 months postterm. Assessments of infant temperament, quality of early parenting interactions, contextual variables, and toddler effortful control and behavior problems were conducted. Results supported differential susceptibility and dual risk models in addition to documenting main effects of early parenting on children’s emerging self-regulation. Our data suggested that preterm or low birth weight infants who were prone to distress or rated by mothers as more difficult were particularly susceptible to the effects of early negative parenting. PMID:21262047

Time-dependent calculations of transfer ionization by fast proton-helium collision in one-dimensional kinematics

NASA Astrophysics Data System (ADS)

Serov, Vladislav V.; Kheifets, A. S.

2014-12-01

We analyze a transfer ionization (TI) reaction in the fast proton-helium collision H++He →H0+He2 ++ e- by solving a time-dependent Schrödinger equation (TDSE) under the classical projectile motion approximation in one-dimensional kinematics. In addition, we construct various time-independent analogs of our model using lowest-order perturbation theory in the form of the Born series. By comparing various aspects of the TDSE and the Born series calculations, we conclude that the recent discrepancies of experimental and theoretical data may be attributed to deficiency of the Born models used by other authors. We demonstrate that the correct Born series for TI should include the momentum-space overlap between the double-ionization amplitude and the wave function of the transferred electron.

A molecularly based theory for electron transfer reorganization energy.

PubMed

Zhuang, Bilin; Wang, Zhen-Gang

2015-12-14

Using field-theoretic techniques, we develop a molecularly based dipolar self-consistent-field theory (DSCFT) for charge solvation in pure solvents under equilibrium and nonequilibrium conditions and apply it to the reorganization energy of electron transfer reactions. The DSCFT uses a set of molecular parameters, such as the solvent molecule's permanent dipole moment and polarizability, thus avoiding approximations that are inherent in treating the solvent as a linear dielectric medium. A simple, analytical expression for the free energy is obtained in terms of the equilibrium and nonequilibrium electrostatic potential profiles and electric susceptibilities, which are obtained by solving a set of self-consistent equations. With no adjustable parameters, the DSCFT predicts activation energies and reorganization energies in good agreement with previous experiments and calculations for the electron transfer between metallic ions. Because the DSCFT is able to describe the properties of the solvent in the immediate vicinity of the charges, it is unnecessary to distinguish between the inner-sphere and outer-sphere solvent molecules in the calculation of the reorganization energy as in previous work. Furthermore, examining the nonequilibrium free energy surfaces of electron transfer, we find that the nonequilibrium free energy is well approximated by a double parabola for self-exchange reactions, but the curvature of the nonequilibrium free energy surface depends on the charges of the electron-transferring species, contrary to the prediction by the linear dielectric theory.

Condom provision and education in Minnesota public schools: a telephone survey of parents.

PubMed

Eisenberg, Marla E; Bernat, Debra H; Bearinger, Linda H; Resnick, Michael D

2009-09-01

Increasing correct and consistent condom use among sexually active adolescents continues to be a critical public health goal, with schools serving as key agents for achieving this goal through sexuality education and condom use provision. This research aims to describe the views of parents regarding school-based condom distribution and education programs, and examines how these views differ across demographic groups. Parents of school-age children in Minnesota were surveyed in telephone interviews (N = 1605; 63% participation) regarding their beliefs about condom availability and education. Chi-square tests of significance were used to detect differences in agreement with each statement for 10 demographic and personal characteristics. A majority of respondents held supportive views about condom availability and education programs. Strongest support centered on statements in the survey about teenagers needing information about condoms (86%) and showing actual condoms during classroom lessons (77%). Approximately two thirds of the parents agreed that school-based instruction about condoms should be "allowed" at the high school level (65%), and one fifth (21%) believed that this type of education should be "required." Support for condom availability and education programs differed significantly according to certain personal characteristics, with less supportive views from self-identified Born Again Christians and politically conservative parents. Public discourse regarding school-based sexuality education should include the viewpoints of parents of school-aged children as key stakeholders. Parents' perspectives provide unique and critical insights that school administrators and educators should consider as they develop educational and programmatic offerings regarding condoms.

[Behavioral characteristics of the only child vs first-born and children with siblings].

PubMed

Tavares, Marcelo B; Fuchs, Felipe Costa; Diligenti, Felipe; de Abreu, José Ricardo Pinto; Rohde, Luis Augusto; Fuchs, Sandra Costa

2004-03-01

To assess the impact of being an only child on characteristics of parental and peer relationships, school achievement, social and sexual behavior. In the total, 360 adolescents identified at third year of high school were sampled from a private school from Porto Alegre in 2000 and 2001. Fifteen to nineteen years old male and female were selected in a cross-sectional study. Assessment of demographic data, education of the parents, birth order (only child, first born and non-first born children), cigarette smoking, alcoholic beverages consumption, illicit drug use, school achievement, social and sexual behavior were gathered with a pre-tested self-administered questionnaire, anonymously fulfilled at the classroom. This study encompassed 8% of only children, 35% first-born, and 57% non-first born adolescents of a socioeconomic homogeneous sample. Social behavior, parents and peer relationships, sports participation, smoking and illicit drug were not associated with birth order. Only children were less likely to report an episode of alcohol intoxication (39%) than first-born (68.9%; p=0.03) and adolescents with siblings (72.3%; p<0.001). Only children had high school achievement than adolescents with siblings (p=0.03). Sexual behavior distinguished only children due to younger age at first sexual intercourse and lower rate of heterosexual self-identification, which persisted even after adjustment for confounding variables in comparison with non first-born adolescents (p=0.038). Our findings suggest that the status of being only child is not associated with a poor outcome in several areas of the development. The impact of the presence of siblings in the development of sexual identification should be further explored.

Psychosocial working conditions and self-reported long-term illness: a population-based study of Swedish-born and foreign-born employed persons.

PubMed

Sundquist, Jan; Ostergren, Per-Olof; Sundquist, Kristina; Johansson, Sven-Erik

2003-11-01

Knowledge pertaining to the relationship between migration status and psychosocial job characteristics and long-term illness is not readily available in the international literature. The aim of this study is to analyse the cross-sectional associations between high psychological job demands and low decision latitude (high job strain), work-related social support and long-term illness among foreign-born and Swedish-born people. The present study combines four annual simple random samples covering 1994-97 from the Swedish Annual Level of Living Survey (SALLS). A sub-sample, including only employed persons and consisting of 10,072 Swedish-born persons, 710 labour migrants and 333 refugees aged 25-64 years, was analysed using logistic regression. Refugees had a higher risk (OR=1.33; 95% CI: 1.05-1.69) of long-term illness than Swedes. Moreover, those experiencing both high job demands and a low decision latitude ran an increased risk (OR=1.74; 95% CI: 1.42-2.13) of long-term illness. About 63% of the refugees among the unskilled/skilled manual workers had low decision latitudes in comparison with 17% of the intermediate and senior salaried employees. There were only small differences in job demands between labour immigrants, refugees and Swedes. There was no interaction between migration status and high job strain. However, refugees with low social support had nearly twice as high a risk of long-term illness as Swedes with high-level work-related social support. Refugees ran a higher risk of long-term illness than Swedes. Although there were no differences in risk between labour immigrants, refugees and Swedes under job strain, refugees with low work-related social support had a high risk of long-term illness. Unskilled/skilled refugee workers had lower decision latitudes than Swedes.

AGED DOMINANT NEGATIVE p38α MAPK MICE ARE RESISTANT TO AGE-DEPENDENT DECLINE IN ADULT-NEUROGENESIS AND CONTEXT DISCRIMINATION FEAR CONDITIONING

PubMed Central

Cortez, IbDanelo; Bulavin, Dmitry V.; Wu, Ping; McGrath, Erica L; Cunningham, Kathryn A; Wakamiya, Maki; Papaconstantinou, John; Dineley, Kelly T

2018-01-01

A major aspect of mammalian aging is the decline in functional competence of many self-renewing cell types, including adult-born neuronal precursors. Since age-related senescence of self-renewal occurs simultaneously with chronic up-regulation of the p38MAPKalpha (p38α) signaling pathway, we used the dominant negative mouse model for attenuated p38α activity (DN-p38αAF/+ ) in which Thr180 and Tyr182 are mutated (T→A/Y→F) to prevent phosphorylation activation (DN-p38αAF/+) and kinase activity. As a result, aged DN-p38αAF/+ mice are resistant to age-dependent decline in proliferation and regeneration of several peripheral tissue progenitors when compared to wild-type littermates. Aging is the major risk factor for non-inherited forms of Alzheimer’s disease (AD); environmental and genetic risk factors that accelerate the senescence phenotype are thought to contribute to an individual’s relative risk. In the present study, we evaluated aged DN-p38αAF/+ and wildtype littermates in a series of behavioral paradigms to test if p38α mutant mice exhibit altered baseline abnormalities in neurological reflexes, locomotion, anxiety-like behavior, and age-dependent cognitive decline. While aged DN-p38αAF/+ and wildtype littermates appear equal in all tested baseline neurological and behavioral parameters, DN-p38αAF/+ exhibit superior context discrimination fear conditioning. Context discrimination is a cognitive task that is supported by proliferation and differentiation of adult-born neurons in the dentate gyrus of the hippocampus. Consistent with enhanced context discrimination in aged DN-p38αAF/+, we discovered enhanced production of adult-born neurons in the dentate gyrus of DN-p38αAF/+ mice compared to wildtype littermates. Our findings support the notion that p38α inhibition has therapeutic utility in aging diseases that affect cognition, such as AD. PMID:27765672

Aged dominant negative p38α MAPK mice are resistant to age-dependent decline in adult-neurogenesis and context discrimination fear conditioning.

PubMed

Cortez, IbDanelo; Bulavin, Dmitry V; Wu, Ping; McGrath, Erica L; Cunningham, Kathryn A; Wakamiya, Maki; Papaconstantinou, John; Dineley, Kelly T

2017-03-30

A major aspect of mammalian aging is the decline in functional competence of many self-renewing cell types, including adult-born neuronal precursors. Since age-related senescence of self-renewal occurs simultaneously with chronic up-regulation of the p38MAPKalpha (p38α) signaling pathway, we used the dominant negative mouse model for attenuated p38α activity (DN-p38α AF/+ ) in which Thr180 and Tyr182 are mutated (T→A/Y→F) to prevent phosphorylation activation (DN-p38α AF/+ ) and kinase activity. As a result, aged DN-p38α AF/+ mice are resistant to age-dependent decline in proliferation and regeneration of several peripheral tissue progenitors when compared to wild-type littermates. Aging is the major risk factor for non-inherited forms of Alzheimer's disease (AD); environmental and genetic risk factors that accelerate the senescence phenotype are thought to contribute to an individual's relative risk. In the present study, we evaluated aged DN-p38α AF/+ and wildtype littermates in a series of behavioral paradigms to test if p38α mutant mice exhibit altered baseline abnormalities in neurological reflexes, locomotion, anxiety-like behavior, and age-dependent cognitive decline. While aged DN-p38α AF/+ and wildtype littermates appear equal in all tested baseline neurological and behavioral parameters, DN-p38α AF/+ exhibit superior context discrimination fear conditioning. Context discrimination is a cognitive task that is supported by proliferation and differentiation of adult-born neurons in the dentate gyrus of the hippocampus. Consistent with enhanced context discrimination in aged DN-p38α AF/+ , we discovered enhanced production of adult-born neurons in the dentate gyrus of DN-p38α AF/+ mice compared to wildtype littermates. Our findings support the notion that p38α inhibition has therapeutic utility in aging diseases that affect cognition, such as AD. Copyright © 2016 Elsevier B.V. All rights reserved.

BORN CROSS SECTIONS FOR INELASTIC SCATTERING OF ELECTRONS BY HYDROGEN ATOMS. III. 5s, 5p, 5d, 5f, 5g STATES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milford, S.N.; Morrissey, J.J.; Scanlon, J.H.

1960-12-01

Born total cross sections were computed for the strong optically allowed transitions from n = 5 to n' = 6, at incident energies between 0.2 and 1361 ev. Thirty energy values were considered for the 5s to 6p and 5g to 6h cases, and nine for the other transitions. The cross sections obtained were larger than those of comparable transitions for lower n. The Bethe (dipole) approximation was also used, and was found to give good agreement with the Born results down to relatively low energies ( approx equal 3 ev). (auth)

It's not how much you play, but how much you enjoy the game: the longitudinal associations between adolescents' self-esteem and the frequency versus enjoyment of involvement in sports.

PubMed

Adachi, Paul J C; Willoughby, Teena

2014-01-01

The frequency of involvement in sports often has been concurrently and longitudinally associated with higher self-esteem. The interpretation of this association consistently has been framed as involvement in sports leading to higher levels of self-esteem over time (i.e., socialization effect), although no studies have tested whether higher levels of self-esteem lead to increased involvement in sports over time (i.e., selection effect). Another important aspect of involvement in sports that may be related to self-esteem is the degree to which youth enjoy sports. However, this aspect has received much less attention. To address these gaps in the literature, we first examined the bidirectional effects between self-esteem and the frequency of involvement in sports with 1,492 adolescents (50.8 % female; 92.4 % Canadian-born) over 4 years. Higher levels of self-esteem predicted greater involvement in sports over time, but greater involvement in sports did not predict higher levels of self-esteem over time, offering support only for selection effects. We then tested the bidirectional effects between the enjoyment of sports and self-esteem and found evidence of both socialization and selection effects. Specifically, greater enjoyment of sports predicted higher self-esteem over time, and higher self-esteem predicted greater enjoyment of sports over time. These novel findings suggest that adolescents with higher self-esteem play sports more frequently and enjoy sports more than adolescents with lower self-esteem. In addition, the degree to which adolescents enjoy sports may be more important for increasing self-esteem than the frequency with which adolescents play sports.

42 CFR 137.264 - To what extent may the Secretary require the Self-Governance Tribe to return property that was...

Code of Federal Regulations, 2012 CFR

2012-10-01

... the property has a per item current fair market value, less the cost of improvements borne by the Self... 42 Public Health 1 2012-10-01 2012-10-01 false To what extent may the Secretary require the Self... HUMAN SERVICES TRIBAL SELF-GOVERNANCE Reassumption § 137.264 To what extent may the Secretary require...

42 CFR 137.264 - To what extent may the Secretary require the Self-Governance Tribe to return property that was...

Code of Federal Regulations, 2014 CFR

2014-10-01

... the property has a per item current fair market value, less the cost of improvements borne by the Self... 42 Public Health 1 2014-10-01 2014-10-01 false To what extent may the Secretary require the Self... HUMAN SERVICES TRIBAL SELF-GOVERNANCE Reassumption § 137.264 To what extent may the Secretary require...

42 CFR 137.264 - To what extent may the Secretary require the Self-Governance Tribe to return property that was...

Code of Federal Regulations, 2010 CFR

2010-10-01

... the property has a per item current fair market value, less the cost of improvements borne by the Self... 42 Public Health 1 2010-10-01 2010-10-01 false To what extent may the Secretary require the Self... HUMAN SERVICES TRIBAL SELF-GOVERNANCE Reassumption § 137.264 To what extent may the Secretary require...

42 CFR 137.264 - To what extent may the Secretary require the Self-Governance Tribe to return property that was...

Code of Federal Regulations, 2011 CFR

2011-10-01

... the property has a per item current fair market value, less the cost of improvements borne by the Self... 42 Public Health 1 2011-10-01 2011-10-01 false To what extent may the Secretary require the Self... HUMAN SERVICES TRIBAL SELF-GOVERNANCE Reassumption § 137.264 To what extent may the Secretary require...

42 CFR 137.264 - To what extent may the Secretary require the Self-Governance Tribe to return property that was...

Code of Federal Regulations, 2013 CFR

2013-10-01

... the property has a per item current fair market value, less the cost of improvements borne by the Self... 42 Public Health 1 2013-10-01 2013-10-01 false To what extent may the Secretary require the Self... HUMAN SERVICES TRIBAL SELF-GOVERNANCE Reassumption § 137.264 To what extent may the Secretary require...

Born at the right time? Childhood health and the business cycle.

PubMed

Angelini, Viola; Mierau, Jochen O

2014-05-01

We analyze the relationship between the state of the business cycle at birth and childhood health. We use a retrospective survey on self-reported childhood health for ten Western European countries and combine it with historically and internationally comparable data on the Gross Domestic Product. We validate the self-reported data by comparing them to realized illness spells. We find a positive relationship between being born in a recession and childhood health. This relationship is not driven by selection effects due to heightened infant mortality during recessions. Placebo regressions indicate that the observed effect is not spurious. Copyright © 2014 Elsevier Ltd. All rights reserved.

An evaluation of data for 10 children born to mothers who attempted suicide by taking large doses of alprazolam during pregnancy.

PubMed

Gidai, J; Acs, N; Bánhidy, F; Czeizel, A E

2008-01-01

FDA has identified alprazolam, a new type of benzodiazepine, as pregnancy category D. The objective of this study was to evaluate the effects on fetal development of very large doses of alprazolam that were used for suicide attempts during pregnancy. Pregnant women were identified among the patients of the Department of Toxicology Internal Medicine, Korányi Hospital, Budapest, who were admitted as self-poisoned subjects from a total population of the three million people of Budapest and its surrounding region. Rates of congenital abnormalities, intrauterine fetal development, and cognitive-behavioral status were compared between children born to mothers who attempted suicide during pregnancy using alprazolam alone or in combination with other drugs and in their sib controls. Between 1984 and 1993, 559 pregnant women attempted suicide during pregnancy with drugs: 30 of these women self-poisoned with alprazolam, 10 delivered live-born infants who were examined. Doses of alprazolam used were between 7.5 and 100 mg, with a mean of 30 mg. Six of the 10 exposed children were born to mothers who attempted suicide between the 6th and 12th postconceptional weeks. Of the 10 exposed children, two had congenital abnormalities. One had a multiple congenital abnormality that included atypical gastroschisis and minor anomalies; an association of this defect and the 30 mg alprazolam used for self-poisoning in the 14th postconceptional week cannot be excluded. Another exposed child had mild pectus excavatum, but the times of the suicide attempt and the critical period for producing this defect did not overlap. Of 12 sibs, one had a multiple congenital abnormality. Thus, the rate of congenital abnormalities did not significantly differ between exposed children and their sibs. Mean birth weight was higher for babies born to mothers who attempted suicide by alprazolam during pregnancy than in their sib controls. Cognitive status and behavioral scale of the exposed children did not indicate fetotoxic effects, including neurotoxic effects, of large doses of alprazolam. The large doses of alprazolam used for self-poisoning during pregnancy did not result in a significantly higher rate of congenital abnormalities; however, there were only 10 self-poisoned pregnant women, and an association of one multiple congenital abnormality with a large dose of alprazolam cannot be excluded. The findings in this study did not identify fetotoxicity, including neurotoxicity, of very large doses of alprazolam. Our study shows that the self-poisoning model is feasible and provides beneficial information for use in estimating human teratogenic and fetotoxic risks of drugs.

Psychological growth and well-being in individuals born with cleft: An application of self-determination theory.

PubMed

Searle, Aidan; Neville, Patricia; Waylen, Andrea

2017-04-01

Many studies of individuals born with cleft lip and/or palate (CLP) address the psychological impact of CLP in terms of stigma and/or 'resilience'. The present study challenges the usefulness of resilience in CLP research with the application of self-determination theory (SDT). It is proposed that SDT can serve to better understand how individuals born with CLP can achieve psychological growth and well-being. Interviews were conducted with 15 individuals born with CLP in the UK. A thematic analysis was conducted and four main themes emerged: (1) personal challenges, (2) support and strategies for social interaction, (3) experience of treatment and outcomes, and (4) personal development. The thematic analysis and the interpretation in the context of SDT leads to a greater understanding of the development of psychological growth and well-being in individuals born with CLP. Interpreting the life experiences of individuals with CLP through the theoretical lens of SDT allows the conceptualisation of individuals with CLP as a positive psychological resource when faced with the exclusionary practice of stigma. This resourcefulness is primarily nurtured by a supportive family and social environment that leads to the development of positive psychological growth and well-being. A new direction in CLP research is proposed that seeks to inform and implement change in professional practice to support individuals with CLP and their families.

Dirty two-band superconductivity with interband pairing order

NASA Astrophysics Data System (ADS)

Asano, Yasuhiro; Sasaki, Akihiro; Golubov, Alexander A.

2018-04-01

We study theoretically the effects of random nonmagnetic impurities on the superconducting transition temperature T c in a two-band superconductor characterized by an equal-time s-wave interband pairing order parameter. Because of the two-band degree of freedom, it is possible to define a spin-triplet s-wave pairing order parameter as well as a spin-singlet s-wave order parameter. The former belongs to odd-band-parity symmetry class, whereas the latter belongs to even-band-parity symmetry class. In a spin-singlet superconductor, T c is insensitive to the impurity concentration when we estimate the self-energy due to the random impurity potential within the Born approximation. On the other hand in a spin-triplet superconductor, T c decreases with the increase of the impurity concentration. We conclude that Cooper pairs belonging to odd-band-parity symmetry class are fragile under the random impurity potential even though they have s-wave pairing symmetry.

Three-dimensional imaging of buried objects in very lossy earth by inversion of VETEM data

USGS Publications Warehouse

Cui, T.J.; Aydiner, A.A.; Chew, W.C.; Wright, D.L.; Smith, D.V.

2003-01-01

The very early time electromagnetic system (VETEM) is an efficient tool for the detection of buried objects in very lossy earth, which allows a deeper penetration depth compared to the ground-penetrating radar. In this paper, the inversion of VETEM data is investigated using three-dimensional (3-D) inverse scattering techniques, where multiple frequencies are applied in the frequency range from 0-5 MHz. For small and moderately sized problems, the Born approximation and/or the Born iterative method have been used with the aid of the singular value decomposition and/or the conjugate gradient method in solving the linearized integral equations. For large-scale problems, a localized 3-D inversion method based on the Born approximation has been proposed for the inversion of VETEM data over a large measurement domain. Ways to process and to calibrate the experimental VETEM data are discussed to capture the real physics of buried objects. Reconstruction examples using synthesized VETEM data and real-world VETEM data are given to test the validity and efficiency of the proposed approach.

Emulsifier-free emulsion polymerization produces highly charged, monodisperse particles for near infrared photonic crystals.

PubMed

Reese, Chad E; Asher, Sanford A

2002-04-01

We have developed emulsifier-free, emulsion polymerization recipes for the synthesis of highly charged, monodisperse latex particles of diameters between 500 and 1100 nm. These latexes consist of poly[styrene-(co-2-hydroxyethyl methacrylate)] spherical particles whose surfaces are functionalized with sulfate and carboxylic acid groups. These highly charged, monodisperse particles readily self-assemble into robust, three-dimensionally ordered crystalline colloidal array photonic crystals that Bragg diffract light in the near infrared spectral region. By altering the particle number density, the diffraction wavelength can be tuned from approximately 1000 to approximately 4000 nm.

Quality of Life of Adolescents and Young Adults Born at High Risk

ERIC Educational Resources Information Center

Dahan-Oliel, Noemi; Majnemer, Annette; Mazer, Barbara

2011-01-01

Research on quality of life (QoL) of adolescents and young adults born preterm and those with congenital heart disease (CHD) was systematically reviewed, and factors associated with QoL were identified. Forty-five studies met the inclusion criteria for review. Although the majority of studies found that self-reported QoL of adolescents and young…

A globally accurate theory for a class of binary mixture models

NASA Astrophysics Data System (ADS)

Dickman, Adriana G.; Stell, G.

The self-consistent Ornstein-Zernike approximation results for the 3D Ising model are used to obtain phase diagrams for binary mixtures described by decorated models, yielding the plait point, binodals, and closed-loop coexistence curves for the models proposed by Widom, Clark, Neece, and Wheeler. The results are in good agreement with series expansions and experiments.

Acculturation and well-being among Arab-European mixed-ethnic adolescents in Israel.

PubMed

Abu-Rayya, Hisham Motkal

2006-11-01

To examine the relationship between two ethnic dimensions (Arab and European), and between a modified version of Berry's four acculturation styles (integration, assimilation into the Arab heritage, assimilation into the European heritage, and marginalization) and measures of psychological well-being among adolescents born to European mothers and Israeli Arab fathers. A total of 127 Arab-European adolescents (aged 13 to 18 years; 64 males and 63 females) in Israel completed ethnic identification and well-being measures. Arab and European ethnic identifications emerged as being uncorrelated among the participants, providing a basis to use four acculturation styles to describe participants' variations in ethnic identification. The study found that integration and assimilation into the Arab heritage were connected with higher levels of desirable well-being correlates (self-esteem and positive relations with others) and with lower levels of undesirable correlates (depression and anxiety). The study also found that although assimilation into the European heritage was linked with high levels of self-esteem and low levels of depression, this style was linked with high levels of anxiety and low levels of positive relations with others. The marginalization style was consistently positively associated with high levels of poor mental health. The underlying assumption of Berry's four-fold model, notably the independence of ethnic identifications, tends to be borne out among mixed-ethnic individuals. On the basis of this independence the study revealed that a modified version of Berry's four acculturation styles could prevail among Arab-European individuals over the period of adolescence and that these styles play a predictive role in well-being measures of the individuals. Specifically, integration and assimilation into the Arab heritage emerged to be the best options for individuals' well-being; individuals' assimilation into their European heritage seemed to be simultaneously connected with high and low well-being outcomes; and ethnic marginalization of individuals was consistently correlated with poor well-being.

Complex polarization propagator approach in the restricted open-shell, self-consistent field approximation: the near K-edge X-ray absorption fine structure spectra of allyl and copper phthalocyanine.

PubMed

Linares, Mathieu; Stafström, Sven; Rinkevicius, Zilvinas; Ågren, Hans; Norman, Patrick

2011-05-12

A presentation of the complex polarization propagator in the restricted open-shell self-consistent field approximation is given. It rests on a formulation of a resonant-convergent, first-order polarization propagator approach that makes it possible to directly calculate the X-ray absorption cross section at a particular frequency without explicitly addressing the excited states. The quality of the predicted X-ray spectra relates only to the type of density functional applied without any separate treatment of dynamical relaxation effects. The method is applied to the calculation of the near K-edge X-ray absorption fine structure spectra of allyl and copper phthalocyanine. Comparison is made between the spectra of the radicals and those of the corresponding cations and anions to assess the effect of the increase of electron charge in the frontier orbital. The method offers the possibility for unique assignment of symmetry-independent atoms. The overall excellent spectral agreement motivates the application of the method as a routine precise tool for analyzing X-ray absorption of large systems of technological interest.

Development of FullWave : Hot Plasma RF Simulation Tool

NASA Astrophysics Data System (ADS)

Svidzinski, Vladimir; Kim, Jin-Soo; Spencer, J. Andrew; Zhao, Liangji; Galkin, Sergei

2017-10-01

Full wave simulation tool, modeling RF fields in hot inhomogeneous magnetized plasma, is being developed. The wave equations with linearized hot plasma dielectric response are solved in configuration space on adaptive cloud of computational points. The nonlocal hot plasma dielectric response is formulated in configuration space without limiting approximations by calculating the plasma conductivity kernel based on the solution of the linearized Vlasov equation in inhomogeneous magnetic field. This approach allows for better resolution of plasma resonances, antenna structures and complex boundaries. The formulation of FullWave and preliminary results will be presented: construction of the finite differences for approximation of derivatives on adaptive cloud of computational points; model and results of nonlocal conductivity kernel calculation in tokamak geometry; results of 2-D full wave simulations in the cold plasma model in tokamak geometry using the formulated approach; results of self-consistent calculations of hot plasma dielectric response and RF fields in 1-D mirror magnetic field; preliminary results of self-consistent simulations of 2-D RF fields in tokamak using the calculated hot plasma conductivity kernel; development of iterative solver for wave equations. Work is supported by the U.S. DOE SBIR program.

A balloon measurement of the isotopic composition of galactic cosmic ray iron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grove, J.E.

1989-01-01

The isotopic composition of galactic cosmic ray iron in the energy interval of approximately 1550 to 2200 MeV/nucleon was measured using a balloon-borne mass spectrometer. The instrument was flown from Palestine, Texas, in May 1984 for greater than 35 hours at an atmospheric depth of approximately 6 g/sq cm. Masses were derived by the Cerenkov-Energy technique. The Cerenkov counter employed a silica aerogel radiator with an index of refraction n = 1.1. Particle energies were measured in a stack of NaI(Tl) scintillators, which also provided particle trajectories. A detailed discussion of the sources of mass uncertainty is presented, including anmore » analytic model of the contribution from fluctuations in the Cerenkov yield from knock-on electrons. The achieved mass resolution is approximately 0.65 amu, which is consistent with the theoretical estimate. An Fe-54/Fe-56 abundance ratio of 0.14(sup +0.18)(sub -0.11) and an 84 percent confidence upper limit of Fe-58/Fe-56 is less than or = to 0.07 at the top of the atmosphere is reported. Combining the data with those of precious measurements of the composition of iron at lower energies, and using a model of the galactic propagation, cosmic-ray source abundance ratios of Fe-54/Fe-56 = 0.064(sup +0.032)(sub -0.027) and Fe-58/F3-56 is less than or = to 0.062 were derived. These values are consistent with the composition of solar system iron and place restrictions on the conditions under which cosmic-ray iron is synthesized.« less

Towards a complete North American Anabaptist Genealogy II: analysis of inbreeding.

PubMed

Agarwala, R; Schäffer, A A; Tomlin, J F

2001-08-01

We describe a large genealogy data base, which can be searched by computer, of 295,095 Amish and Mennonite individuals. The data base was constructed by merging our existing Anabaptist Genealogy Database 2.0 containing approximately 85,000 individuals with a genealogy file containing approximately 242,000 individuals, kindly provided by Mr. James Hostetler. The merging process corrected thousands of inconsistencies and eliminated hundreds of duplicate individuals. Geneticists have long been interested in Anabaptist populations because they are closed and have detailed written genealogies. The creation of an enlarged and unified data base affords the opportunity to examine inbreeding trends and correlates in these populations. We show the following results. The frequency of consanguineous marriages shows steady increase over time and reached approximately 85% for individuals born in 1940-1959. Among consanguineous marriages, the median kinship coefficient stayed stable in the 19th century, but rose from 0.0115 to 0.0151 in the 20th century. There are statistically significant associations (p < 0.0001) between inbreeding and family size and interbirth intervals in the 20th century. There is an association (p < 0.0005) between inbreeding and early death for individuals born in 1920-1959. However, this association reverses dramatically (p < 0.0005 in the opposite direction) for individuals born in 1960-1979. We tested for an association between inbreeding and being the mother of twins, but found none.

Effects of a finite aperture on the Inverse Born Approximation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kogan, V.G.; Rose, J.H.

1983-01-01

One of the most important effects of complex part geometry is that the available entrance and exit angles for ultrasound are limited. We will present a study of the Inverse Born approximation in which we have data for incident (and exit) directions confined to a conical aperture. Modeling the direct problem by the Born Approximation, we obtained analytical results for (1) a weak spherical inclusion, and (2) a penny shaped crack (modeled by an oblate spheroid). General results are: (a) the value of the characteristic function ..gamma.. is constant in the interior of the flaw, but reduced in value; (b)more » the discontinuity at the boundary of the flaw occurs over the lighted portion of the flaw; (c) this discontinuity is contrasted by a region where ..gamma.. is negative; and (d) new non-physical discontinuities and non-analyticities appear in the reconstructed characteristic function. These general features also appear in numerical calculations which use as input strong scattering data from a spherical void and a flat penny shaped crack in Titanium. The numerical results can be straightforwardly interpreted in terms of the analytical calculation mentioned above, indicating that they will be useful in the study of realistic flaws. We conclude by discussing the stabilization of the aperture limited inversion problem and the removal of non-physical features in the reconstruction.« less

Does really Born Oppenheimer approximation break down in charge transfer processes? An exactly solvable model

NASA Astrophysics Data System (ADS)

Kuznetsov, Alexander M.; Medvedev, Igor G.

2006-05-01

Effects of deviation from the Born-Oppenheimer approximation (BOA) on the non-adiabatic transition probability for the transfer of a quantum particle in condensed media are studied within an exactly solvable model. The particle and the medium are modeled by a set of harmonic oscillators. The dynamic interaction of the particle with a single local mode is treated explicitly without the use of BOA. Two particular situations (symmetric and non-symmetric systems) are considered. It is shown that the difference between the exact solution and the true BOA is negligibly small at realistic parameters of the model. However, the exact results differ considerably from those of the crude Condon approximation (CCA) which is usually considered in the literature as a reference point for BOA (Marcus-Hush-Dogonadze formula). It is shown that the exact rate constant can be smaller (symmetric system) or larger (non-symmetric one) than that obtained in CCA. The non-Condon effects are also studied.

Cross sections and rate coefficients for inner-shell excitation of Li-like ions with 6 < Z < 42

NASA Astrophysics Data System (ADS)

Safronova, U. I.; Safronova, M. S.; Kato, T.

1996-07-01

Excitation cross sections and rate coefficients by electron impact were calculated for the 1s22s-1s2s2p, 1s22s-1s2s2 and 1s22s-1s2p2 transitions of the Li-like ions (C IV, N V, O VI, Ne VIII, Mg X, Al XI, Si XII, S XIV, Ar XVI, Ca XVIII, Ti XX, Fe XXIV, Ni XXVI, Zn XXVIII, Ge XXX, Se XXXII, Kr XXXIV and Mo XXXX) in the Coulomb-Born approximation with exchange including relativistic effects and configuration interaction. Level energies, mixing coefficients and transition wavelengths and probabilities were also computed. Calculations performed by the 1/Z perturbation theory and Coulomb-Born approximation are compared with the R-matrix method and the distorted-wave approximation were Z is the nuclear charge. Formulae obtained for the angular factors of n-electron atomic system allow one to generalize this method to an arbitrary system of highly charged ions.

Favourable changes in economic well-being and self-rated health among the elderly

PubMed Central

Brenes-Camacho, Gilbert

2011-01-01

Adverse economic shocks exert an influence on health perceptions, but little is known about the effect of sudden positive changes in a person’s financial situation on self-rated health, particularly among low income people. This paper explores the association between an increase in the amount of non-contribution pensions, public cash transfers given to Costa Rican elderly of low socio-economic status (SES) and changes in self-rated health over time. The analysis is based on data from CRELES, the “Costa Rican Study on Longevity and Healthy Aging”, which is based on a probabilistic sample of people born in 1945 or earlier, and living in Costa Rica by 2002. The fieldwork for the first and second waves of CRELES was conducted from 2004 to 2006, and from 2006 to 2008, respectively. The Costa Rican Government raised the amount of the non-contribution pension for the poor 100% before July 2007, and an additional 100% after that date. Due to the CRELES fieldwork schedule, the data have a natural quasi-experimental design, given that approximately half of CRELES respondents were interviewed before July 2007, independently of their status in receiving the public cash transfers. Using random effects ordered probit regression models, we find that people who experienced such increase report a greater improvement in self-rated health between waves than those who experienced a smaller increase and than the rest of the interviewees. Results suggest that increases in income may lead to a greater improvement in self-rated health. PMID:21440352

Luttinger theorem and imbalanced Fermi systems

NASA Astrophysics Data System (ADS)

Pieri, Pierbiagio; Strinati, Giancarlo Calvanese

2017-04-01

The proof of the Luttinger theorem, which was originally given for a normal Fermi liquid with equal spin populations formally described by the exact many-body theory at zero temperature, is here extended to an approximate theory given in terms of a "conserving" approximation also with spin imbalanced populations. The need for this extended proof, whose underlying assumptions are here spelled out in detail, stems from the recent interest in superfluid trapped Fermi atoms with attractive inter-particle interaction, for which the difference between two spin populations can be made large enough that superfluidity is destroyed and the system remains normal even at zero temperature. In this context, we will demonstrate the validity of the Luttinger theorem separately for the two spin populations for any "Φ-derivable" approximation, and illustrate it in particular for the self-consistent t-matrix approximation.

Average size of random polygons with fixed knot topology.

PubMed

Matsuda, Hiroshi; Yao, Akihisa; Tsukahara, Hiroshi; Deguchi, Tetsuo; Furuta, Ko; Inami, Takeo

2003-07-01

We have evaluated by numerical simulation the average size R(K) of random polygons of fixed knot topology K=,3(1),3(1) musical sharp 4(1), and we have confirmed the scaling law R(2)(K) approximately N(2nu(K)) for the number N of polygonal nodes in a wide range; N=100-2200. The best fit gives 2nu(K) approximately 1.11-1.16 with good fitting curves in the whole range of N. The estimate of 2nu(K) is consistent with the exponent of self-avoiding polygons. In a limited range of N (N greater, similar 600), however, we have another fit with 2nu(K) approximately 1.01-1.07, which is close to the exponent of random polygons.

Application of an extended random-phase approximation to giant resonances in light-, medium-, and heavy-mass nuclei

NASA Astrophysics Data System (ADS)

Tselyaev, V.; Lyutorovich, N.; Speth, J.; Krewald, S.; Reinhard, P.-G.

2016-09-01

We present results of the time blocking approximation (TBA) for giant resonances in light-, medium-, and heavy-mass nuclei. The TBA is an extension of the widely used random-phase approximation (RPA) adding complex configurations by coupling to phonon excitations. A new method for handling the single-particle continuum is developed and applied in the present calculations. We investigate in detail the dependence of the numerical results on the size of the single-particle space and the number of phonons as well as on nuclear matter properties. Our approach is self-consistent, based on an energy-density functional of Skyrme type where we used seven different parameter sets. The numerical results are compared with experimental data.

Dissociation of Self-Motion and Object Motion by Linear Population Decoding That Approximates Marginalization.

PubMed

Sasaki, Ryo; Angelaki, Dora E; DeAngelis, Gregory C

2017-11-15

We use visual image motion to judge the movement of objects, as well as our own movements through the environment. Generally, image motion components caused by object motion and self-motion are confounded in the retinal image. Thus, to estimate heading, the brain would ideally marginalize out the effects of object motion (or vice versa), but little is known about how this is accomplished neurally. Behavioral studies suggest that vestibular signals play a role in dissociating object motion and self-motion, and recent computational work suggests that a linear decoder can approximate marginalization by taking advantage of diverse multisensory representations. By measuring responses of MSTd neurons in two male rhesus monkeys and by applying a recently-developed method to approximate marginalization by linear population decoding, we tested the hypothesis that vestibular signals help to dissociate self-motion and object motion. We show that vestibular signals stabilize tuning for heading in neurons with congruent visual and vestibular heading preferences, whereas they stabilize tuning for object motion in neurons with discrepant preferences. Thus, vestibular signals enhance the separability of joint tuning for object motion and self-motion. We further show that a linear decoder, designed to approximate marginalization, allows the population to represent either self-motion or object motion with good accuracy. Decoder weights are broadly consistent with a readout strategy, suggested by recent computational work, in which responses are decoded according to the vestibular preferences of multisensory neurons. These results demonstrate, at both single neuron and population levels, that vestibular signals help to dissociate self-motion and object motion. SIGNIFICANCE STATEMENT The brain often needs to estimate one property of a changing environment while ignoring others. This can be difficult because multiple properties of the environment may be confounded in sensory signals. The brain can solve this problem by marginalizing over irrelevant properties to estimate the property-of-interest. We explore this problem in the context of self-motion and object motion, which are inherently confounded in the retinal image. We examine how diversity in a population of multisensory neurons may be exploited to decode self-motion and object motion from the population activity of neurons in macaque area MSTd. Copyright © 2017 the authors 0270-6474/17/3711204-16$15.00/0.

Corrections to the one-photon approximation in the 0+-->2+ transition of 12C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paul Gueye; Madeleine Bernheim; J. F. Danel

2001-04-18

Contribution of higher order effects to the one-photon exchange approximation were studied in the first excited state of 12C by comparing inclusive inelastic scattering cross sections of electrons and positrons obtained at the Saclay Linear Accelerator. The data were compared to a distorted wave Born approximation (DWBA)calculation. The results indicate an effect less than 2% within 2sigma, compatible with what was observed in recent elastic scattering measurements.

The graviton luminosity of the sun and other stars

NASA Technical Reports Server (NTRS)

Gould, R. J.

1985-01-01

Graviton production in electron-electron (e-e) and electron-ion (e-z) scattering is evaluated in the Born approximation. The calculation is compared with that for photon production, that is, Coulomb quadrupole bremsstrahlung, and a number of results are taken over from that problem. Application is made to the sun, and it is found that for the solar plasma the main contribution to the graviton luminosity comes from the central core at r/R approximately 0.1. The total luminosity (Lg) in gravitons is about 7.9 x 10 to the 14th ergs/s, close to an earlier estimate by Weinberg (1965, 1972); about 33 percent of the total results from e-e collisions with the rest from e-z collisions (mainly e-p and e-alpha). Approximate corrections to Born formulas are evaluated, and this Lg includes the associated (approximately + or - 10 percent, respectively) modification. The quantum-mechanical aspects of the solar Lg problem are discussed, and it is shown why a previous classical calculation overestimated Lg by about an order of magnitude. Production of gravitons in binary collisions in other types of stars is discussed briefly. It is found that Lg varies very little along the main sequence. White dwarfs have a typical graviton luminosity LWD approximately 10 to the 19th ergs/s, while neutron stars have LNS approximately 10 to the 25th ergs/s; these estimates are very rough.

Postural Complexity Differs Between Infant Born Full Term and Preterm During the Development of Early Behaviors

PubMed Central

Dusing, Stacey C; Izzo, Theresa A.; Thacker, Leroy R.; Galloway, James C

2014-01-01

Background and Aims Postural control differs between infants born preterm and full term at 1–3 weeks of age. It is unclear if differences persist or alter the development of early behaviors. The aim of this longitudinal study was to compare changes in postural control variability during development of head control and reaching in infants born preterm and full term. Methods Eighteen infants born preterm (mean gestational age 28.3±3.1 weeks) were included in this study and compared to existing data from 22 infants born full term. Postural variability was assessed longitudinally using root mean squared displacement and approximate entropy of the center of pressure displacement from birth to 6 months as measures of the magnitude of the variability and complexity of postural control. Behavioral coding was used to quantify development of head control and reaching. Results Group differences were identified in postural complexity during the development of head control and reaching. Infants born preterm used more repetitive and less adaptive postural control strategies than infants born full term. Both groups changed their postural complexity utilized during the development of head control and reaching. Discussion Early postural complexity was decreased in infants born preterm, compared to infants born full term. Commonly used clinical assessments did not identify these early differences in postural control. Altered postural control in infants born preterm influenced ongoing skill development in the first six months of life. PMID:24485170

Genetic Characterization of the Tick-Borne Orbiviruses

PubMed Central

Belaganahalli, Manjunatha N.; Maan, Sushila; Maan, Narender S.; Brownlie, Joe; Tesh, Robert; Attoui, Houssam; Mertens, Peter P. C.

2015-01-01

The International Committee for Taxonomy of Viruses (ICTV) recognizes four species of tick-borne orbiviruses (TBOs): Chenuda virus, Chobar Gorge virus, Wad Medani virus and Great Island virus (genus Orbivirus, family Reoviridae). Nucleotide (nt) and amino acid (aa) sequence comparisons provide a basis for orbivirus detection and classification, however full genome sequence data were only available for the Great Island virus species. We report representative genome-sequences for the three other TBO species (virus isolates: Chenuda virus (CNUV); Chobar Gorge virus (CGV) and Wad Medani virus (WMV)). Phylogenetic comparisons show that TBOs cluster separately from insect-borne orbiviruses (IBOs). CNUV, CGV, WMV and GIV share low level aa/nt identities with other orbiviruses, in ‘conserved’ Pol, T2 and T13 proteins/genes, identifying them as four distinct virus-species. The TBO genome segment encoding cell attachment, outer capsid protein 1 (OC1), is approximately half the size of the equivalent segment from insect-borne orbiviruses, helping to explain why tick-borne orbiviruses have a ~1 kb smaller genome. PMID:25928203

Genetic characterization of the tick-borne orbiviruses.

PubMed

Belaganahalli, Manjunatha N; Maan, Sushila; Maan, Narender S; Brownlie, Joe; Tesh, Robert; Attoui, Houssam; Mertens, Peter P C

2015-04-28

The International Committee for Taxonomy of Viruses (ICTV) recognizes four species of tick-borne orbiviruses (TBOs): Chenuda virus, Chobar Gorge virus, Wad Medani virus and Great Island virus (genus Orbivirus, family Reoviridae). Nucleotide (nt) and amino acid (aa) sequence comparisons provide a basis for orbivirus detection and classification, however full genome sequence data were only available for the Great Island virus species. We report representative genome-sequences for the three other TBO species (virus isolates: Chenuda virus (CNUV); Chobar Gorge virus (CGV) and Wad Medani virus (WMV)). Phylogenetic comparisons show that TBOs cluster separately from insect-borne orbiviruses (IBOs). CNUV, CGV, WMV and GIV share low level aa/nt identities with other orbiviruses, in 'conserved' Pol, T2 and T13 proteins/genes, identifying them as four distinct virus-species. The TBO genome segment encoding cell attachment, outer capsid protein 1 (OC1), is approximately half the size of the equivalent segment from insect-borne orbiviruses, helping to explain why tick-borne orbiviruses have a ~1 kb smaller genome.

Elastic scattering of spin-polarized electrons and positrons from 23Na nuclei

NASA Astrophysics Data System (ADS)

Jakubassa-Amundsen, D. H.

2018-07-01

Differential cross sections and polarization correlations for the scattering of relativistic spin-polarized leptons from unpolarized ground-state sodium nuclei are calculated within the distorted-wave Born approximation (DWBA). Various nuclear ground-state charge distributions are probed. Besides potential scattering, also electric C2 and magnetic M1 and M3 transitions are taken into account. It is shown that even for a light nucleus such as 23Na there are considerable electron-positron differences at high collision energies and large scattering angles. In particular, the symmetry of the Sherman function with respect to a global sign change, as predicted by the second-order Born approximation when replacing electrons by positrons, is broken whenever the diffraction structures come into play beyond 100 MeV.

Coupled-Sturmian and perturbative treatments of electron transfer and ionization in high-energy p-He+ collisions

NASA Astrophysics Data System (ADS)

Winter, Thomas G.; Alston, Steven G.

1992-02-01

Cross sections have been determined for electron transfer and ionization in collisions between protons and He+ ions at proton energies from several hundred kilo-electron-volts to 2 MeV. A coupled-Sturmian approach is taken, extending the work of Winter [Phys. Rev. A 35, 3799 (1987)] and Stodden et al. [Phys. Rev. A 41, 1281 (1990)] to high energies where perturbative approaches are expected to be valid. An explicit connection is made with the first-order Born approximation for ionization and the impulse version of the distorted, strong-potential Born approximation for electron transfer. The capture cross section is shown to be affected by the presence of target basis functions of positive energy near v2/2, corresponding to the Thomas mechanism.

Calculation of the total electron excitation cross section in the Born approximation using Slater wave functions for the Li (2s yields 2p), Li (2s yields 3p), Na (3s yields 4p), Mg (3p yields 4s), Ca (4s yields 4p) and K (4s yields 4p) excitations. M.S. Thesis

NASA Technical Reports Server (NTRS)

Simsic, P. L.

1974-01-01

Excitation of neutral atoms by inelastic scattering of incident electrons in gaseous nebulae were investigated using Slater Wave functions to describe the initial and final states of the atom. Total cross sections using the Born Approximation are calculated for: Li(2s yields 2p), Na(3s yields 4p), k(4s yields 4p). The intensity of emitted radiation from gaseous nebulae is also calculated, and Maxwell distribution is employed to average the kinetic energy of electrons.

Patterns of home and community care service delivery to culturally and linguistically diverse residents of rural Victoria.

PubMed

Ward, Bernadette M; Anderson, Karen S; Sheldon, Maria S

2005-12-01

To describe and compare patterns of Home and Community Care (HACC) utilisation among culturally and linguistically diverse (CALD) people and Australian-born residents of rural Victoria. The HACC Minimum Data Set provides information regarding levels of service provision and coverage in Victoria. Data from January to June 2002 were analysed to provide a profile of client characteristics and service usage in rural Victoria. Patterns of service utilisation were compared with the profile of the CALD population in the 2001 Census. The proportion of CALD residents who are HACC clients is consistent with demographic profiles. However, their extent of service usage is not consistent with patterns of use by Australian-born residents. HACC clients born in non-English-speaking countries, receive 35% less hours of HACC service than their Australian-born counterparts. HACC clients born overseas in English-speaking countries receive nine per cent less hours of HACC service than the Australian-born group (F = 8.9, P = 0.00). Both groups of overseas-born clients use a smaller range of HACC services (F = 1.9, P = 0.16). Planners and service providers need to monitor levels of HACC service delivery among population groups to ensure that CALD population groups receive equitable levels of HACC services. The HACC Minimum Data Set is one source of data that can assist in this process.

Lactose intolerance: from diagnosis to correct management.

PubMed

Di Rienzo, T; D'Angelo, G; D'Aversa, F; Campanale, M C; Cesario, V; Montalto, M; Gasbarrini, A; Ojetti, V

2013-01-01

This review discusses one of the most relevant problems in gastrointestinal clinical practice: lactose intolerance. The role of lactase-persistence alleles the diagnosis of lactose malabsorption the development of lactose intolerance symptoms and its management. Most people are born with the ability to digest lactose, the major carbohydrate in milk and the main source of nutrition until weaning. Approximately, 75% of the world's population loses this ability at some point, while others can digest lactose into adulthood. Symptoms of lactose intolerance include abdominal pain, bloating, flatulence and diarrhea with a considerable intraindividual and interindividual variability in the severity. Diagnosis is most commonly performed by the non invasive lactose hydrogen breath test. Management of lactose intolerance consists of two possible clinical choice not mutually exclusive: alimentary restriction and drug therapy.

Evidence of Soft Dipole Resonance in Li 11 with Isoscalar Character

NASA Astrophysics Data System (ADS)

Kanungo, R.; Sanetullaev, A.; Tanaka, J.; Ishimoto, S.; Hagen, G.; Myo, T.; Suzuki, T.; Andreoiu, C.; Bender, P.; Chen, A. A.; Davids, B.; Fallis, J.; Fortin, J. P.; Galinski, N.; Gallant, A. T.; Garrett, P. E.; Hackman, G.; Hadinia, B.; Jansen, G.; Keefe, M.; Krücken, R.; Lighthall, J.; McNeice, E.; Miller, D.; Otsuka, T.; Purcell, J.; Randhawa, J. S.; Roger, T.; Rojas, A.; Savajols, H.; Shotter, A.; Tanihata, I.; Thompson, I. J.; Unsworth, C.; Voss, P.; Wang, Z.

2015-05-01

The first conclusive evidence of a dipole resonance in Li 11 having isoscalar character observed from inelastic scattering with a novel solid deuteron target is reported. The experiment was performed at the newly commissioned IRIS facility at TRIUMF. The results show a resonance peak at an excitation energy of 1.03 ±0.03 MeV with a width of 0.51 ±0.11 MeV (FWHM). The angular distribution is consistent with a dipole excitation in the distorted-wave Born approximation framework. The observed resonance energy together with shell model calculations show the first signature that the monopole tensor interaction is important in Li 11 . The first ab initio calculations in the coupled cluster framework are also presented.

Effective cluster interactions at alloy surfaces and charge self-consistency: Surface segregation in Ni-10 at. % Al and Cu-Ni

NASA Astrophysics Data System (ADS)

Schulthess, T.; Monnier, R.; Crampin, S.

1994-12-01

First-principles results are presented for the effective cluster interactions at the surface of a random Ni-10 at. % Al alloy. The derivation is based on an extension of the generalized perturbation method to semi-infinite inhomogeneous binary alloys, using a layer version of the Korringa-Kohn-Rostocker multiple-scattering approach in conjunction with the single-site coherent potential approximation to compute the self-consistent electronic structure of the system. When applied to the bulk, the method yields effective pair interactions that have the full point-group symmetry of the lattice to a very high level of numerical accuracy, despite the fact that intra- and interlayer couplings (scattering-path operators) are treated differently, and which are in perfect agreement with those of a recent three-dimensional treatment. Besides the pair terms, a selected class of triplet and quadruplet interactions are calculated, as well as the point interactions induced by the presence of the surface. The value of the latter in the first lattice plane is strongly exaggerated in our approach, leading to a complete segregation of the minority species to the surface. Using a value corresponding to the difference in the surface energies of the pure components for this term leads to the observed Al concentration of ~=25% at the surface. Possible reasons for the shortcomings of the theory are analyzed, and test calculations for the well studied Cu-Ni system show that the free energy of the semi-infinite alloy cannot be approximated by the sum over the single-particle band energies, once charge self-consistency is enforced at the surface.

West nile virus and equine encephalitis viruses: new perspectives.

PubMed

Long, Maureen T

2014-12-01

Mosquito-borne diseases affect horses worldwide. Mosquito-borne diseases generally cause encephalomyelitis in the horse and can be difficult to diagnose antemortem. In addition to general disease, and diagnostic and treatment aspects, this review article summarizes the latest information on these diseases, covering approximately the past 5 years, with a focus on new equine disease encroachments, diagnostic and vaccination aspects, and possible therapeutics on the horizon. Copyright © 2014 Elsevier Inc. All rights reserved.

A longitudinal experimental study comparing the effectiveness of happiness-enhancing strategies in Anglo Americans and Asian Americans.

PubMed

Boehm, Julia K; Lyubomirsky, Sonja; Sheldon, Kennon M

2011-11-01

Growing evidence suggests that well-being interventions can be effective. However, it is unclear whether happiness-increasing practices are equally effective for individuals from different cultural backgrounds. To investigate this question, Anglo Americans and predominantly foreign-born Asian Americans were randomly assigned to express optimism, convey gratitude, or list their past experiences (control group). Multilevel analyses indicated that participants in the optimism and gratitude conditions reported enhanced life satisfaction relative to those in the control condition. However, Anglo Americans in the treatment conditions demonstrated larger increases in life satisfaction relative to Asian Americans, while both cultural groups in the control condition showed the least improvement. These results are consistent with the idea that the value individualist cultures place on self-improvement and personal agency bolsters the efforts of Anglo Americans to become more satisfied, whereas collectivist cultures' de-emphasis of self-focus and individual goals interferes with the efforts of Asian Americans to pursue enhanced well-being.

Racial and Cultural Factors Affecting the Mental Health of Asian Americans

PubMed Central

Miller, Matthew J.; Yang, Minji; Farrell, Jerome A.; Lin, Li-Ling

2011-01-01

In this study, we employed structural equation modeling to test the degree to which racism-related stress, acculturative stress, and bicultural self-efficacy were predictive of mental health in a predominantly community-based sample of 367 Asian American adults. We also tested whether bicultural self-efficacy moderated the relationship between acculturative stress and mental health. Finally, we examined whether generational status moderated the impact of racial and cultural predictors of mental health by testing our model across immigrant and U.S.-born samples. Results indicated that our hypothesized structural model represented a good fit to the total sample data. While racism-related stress, acculturative stress, and bicultural self-efficacy were significant predictors of mental health in the total sample analyses, our generational analyses revealed a differential predictive pattern across generational status. Finally, we found that the buffering effect of bicultural self-efficacy on the relationship between acculturative stress and mental health was significant for U.S.-born individuals only. Implications for research and service delivery are explored. PMID:21977934

Fierz Convergence Criterion: A Controlled Approach to Strongly Interacting Systems with Small Embedded Clusters.

PubMed

Ayral, Thomas; Vučičević, Jaksa; Parcollet, Olivier

2017-10-20

We present an embedded-cluster method, based on the triply irreducible local expansion formalism. It turns the Fierz ambiguity, inherent to approaches based on a bosonic decoupling of local fermionic interactions, into a convergence criterion. It is based on the approximation of the three-leg vertex by a coarse-grained vertex computed from a self-consistently determined cluster impurity model. The computed self-energies are, by construction, continuous functions of momentum. We show that, in three interaction and doping regimes of the two-dimensional Hubbard model, self-energies obtained with clusters of size four only are very close to numerically exact benchmark results. We show that the Fierz parameter, which parametrizes the freedom in the Hubbard-Stratonovich decoupling, can be used as a quality control parameter. By contrast, the GW+extended dynamical mean field theory approximation with four cluster sites is shown to yield good results only in the weak-coupling regime and for a particular decoupling. Finally, we show that the vertex has spatially nonlocal components only at low Matsubara frequencies.

Second Order Born Effects in the Perpendicular Plane Ionization of Xe (5p) Atoms

NASA Astrophysics Data System (ADS)

Purohit, G.; Singh, Prithvi; Patidar, Vinod

We report triple differential cross section (TDCS) results for the perpendicular plane ionization of xenon atoms at incident electron energies 5, 10, 20, 30, and 40 eV above ionization potential. The TDCS calculation have been preformed within the modified distorted wave Born approximation formalism including the second order Born (SBA) amplitude. We compare the (e, 2e) TDCS result of our calculation with the very recent measurements of Nixon and Murray [Phys. Rev. A 85, 022716 (2012)] and relativistic DWBA-G results of Illarionov and Stauffer [J. Phys. B: At. Mol. Opt. Phys. 45, 225202 (2012)] and discuss the process contributing to structure seen in the differential cross section.

Hartree-Fock theory of the inhomogeneous electron gas at a jellium metal surface: Rigorous upper bounds to the surface energy and accurate work functions

NASA Astrophysics Data System (ADS)

Sahni, V.; Ma, C. Q.

1980-12-01

The inhomogeneous electron gas at a jellium metal surface is studied in the Hartree-Fock approximation by Kohn-Sham density functional theory. Rigorous upper bounds to the surface energy are derived by application of the Rayleigh-Ritz variational principle for the energy, the surface kinetic, electrostatic, and nonlocal exchange energy functionals being determined exactly for the accurate linear-potential model electronic wave functions. The densities obtained by the energy minimization constraint are then employed to determine work-function results via the variationally accurate "displaced-profile change-in-self-consistent-field" expression. The theoretical basis of this non-self-consistent procedure and its demonstrated accuracy for the fully correlated system (as treated within the local-density approximation for exchange and correlation) leads us to conclude these results for the surface energies and work functions to be essentially exact. Work-function values are also determined by the Koopmans'-theorem expression, both for these densities as well as for those obtained by satisfaction of the constraint set on the electrostatic potential by the Budd-Vannimenus theorem. The use of the Hartree-Fock results in the accurate estimation of correlation-effect contributions to these surface properties of the nonuniform electron gas is also indicated. In addition, the original work and approximations made by Bardeen in this attempt at a solution of the Hartree-Fock problem are briefly reviewed in order to contrast with the present work.

High-Energy X-rays from J174545.5-285829, the Cannonball: a Candidate Pulsar Wind Nebula Associated with Sgr a East

NASA Technical Reports Server (NTRS)

Nynka, Melania; Hailey, Charles J.; Mori, Kaya; Baganoff, Frederick K.; Bauer, Franz E.; Boggs, Steven E.; Craig, William W.; Christensen, Finn E.; Gotthelf, Eric V.; Harrison, Fiona A.;

2-D Modeling of Nanoscale MOSFETs: Non-Equilibrium Green's Function Approach

NASA Technical Reports Server (NTRS)

Svizhenko, Alexei; Anantram, M. P.; Govindan, T. R.; Biegel, Bryan

2001-01-01

We have developed physical approximations and computer code capable of realistically simulating 2-D nanoscale transistors, using the non-equilibrium Green's function (NEGF) method. This is the most accurate full quantum model yet applied to 2-D device simulation. Open boundary conditions and oxide tunneling are treated on an equal footing. Electrons in the ellipsoids of the conduction band are treated within the anisotropic effective mass approximation. Electron-electron interaction is treated within Hartree approximation by solving NEGF and Poisson equations self-consistently. For the calculations presented here, parallelization is performed by distributing the solution of NEGF equations to various processors, energy wise. We present simulation of the "benchmark" MIT 25nm and 90nm MOSFETs and compare our results to those from the drift-diffusion simulator and the quantum-corrected results available. In the 25nm MOSFET, the channel length is less than ten times the electron wavelength, and the electron scattering time is comparable to its transit time. Our main results are: (1) Simulated drain subthreshold current characteristics are shown, where the potential profiles are calculated self-consistently by the corresponding simulation methods. The current predicted by our quantum simulation has smaller subthreshold slope of the Vg dependence which results in higher threshold voltage. (2) When gate oxide thickness is less than 2 nm, gate oxide leakage is a primary factor which determines off-current of a MOSFET (3) Using our 2-D NEGF simulator, we found several ways to drastically decrease oxide leakage current without compromising drive current. (4) Quantum mechanically calculated electron density is much smaller than the background doping density in the poly silicon gate region near oxide interface. This creates an additional effective gate voltage. Different ways to. include this effect approximately will be discussed.

The health of older Mexican Americans in the long run.

PubMed

González, Hector M; Ceballos, Miguel; Tarraf, Wassim; West, Brady T; Bowen, Mary E; Vega, William A

2009-10-01

We compared risk for several medical illnesses between immigrant and US-born older Mexican Americans to determine the relationship between functional health and years of US residency among immigrants. Cross-sectional, multistage probability sample data for 3050 Mexican Americans aged 65 years or older from 5 US southwestern states were analyzed. Self-rated health, medical illnesses, and functional measures were examined in multivariate regression models that included nativity and years of US residency as key predictors. Self-rated health and medical illnesses of immigrant and US-born groups did not differ significantly. Immigrants with longer US residency had significantly higher cognitive functioning scores and fewer problems with functional activities after adjustment for predisposing and medical need factors. Among older Mexican Americans, immigrant health advantages over their US-born counterparts were not apparent. Immigrants had better health functioning with longer US residency that may derive from greater socioeconomic resources. Our findings suggest that the negative acculturation-health relationship found among younger immigrant adults may become a positive relationship in later life.

Few-particle quantum dynamics-comparing nonequilibrium Green functions with the generalized Kadanoff-Baym ansatz to density operator theory

NASA Astrophysics Data System (ADS)

Hermanns, S.; Balzer, K.; Bonitz, M.

2013-03-01

The nonequilibrium description of quantum systems requires, for more than two or three particles, the use of a reduced description to be numerically tractable. Two possible approaches are based on either reduced density matrices or nonequilibrium Green functions (NEGF). Both concepts are formulated in terms of hierarchies of coupled equations—the Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy for the reduced density operators and the Martin-Schwinger-hierarchy (MS) for the Green functions, respectively. In both cases, similar approximations are introduced to decouple the hierarchy, yet still many questions regarding the correspondence of both approaches remain open. Here we analyze this correspondence by studying the generalized Kadanoff-Baym ansatz (GKBA) that reduces the NEGF to a single-time theory. Starting from the BBGKY-hierarchy we present the approximations that are necessary to recover the GKBA result both, with Hartree-Fock propagators (HF-GKBA) and propagators in second Born approximation. To test the quality of the HF-GKBA, we study the dynamics of a 4-electron Hubbard nanocluster starting from a strong nonequilibrium initial state and compare to exact results and the Wang-Cassing approximation to the BBGKY hierarchy presented recently by Akbari et al. [1].

Ab initio design of laser pulses to control molecular motion

NASA Astrophysics Data System (ADS)

Balint-Kurti, Gabriel; Ren, Qinghua; Manby, Frederick; Artamonov, Maxim; Ho, Tak-San; Rabitz, Herschel; Zou, Shiyang; Singh, Harjinder

2007-03-01

Our recent attempts to design laser pulses entirely theoretically, in a quantitative and accurate manner, so as to fully understand the underlying mechanisms active in the control process will be outlined. We have developed a new Born-Oppenheimer like separation called the electric-nuclear Born-Oppenheimer (ENBO) approximation. In this approximation variations of both the nuclear geometry and of the external electric field are assumed to be slow compared with the speed at which the electronic degrees of freedom respond to these changes. This assumption permits the generation of a potential energy surface that depends not only on the relative geometry of the nuclei, but also on the electric field strength and on the orientation of the molecule with respect to the electric field. The range of validity of the ENBO approximation is discussed. Optimal control theory is used along with the ENBO approximation to design laser pulses for exciting vibrational and rotational motion in H2 and CO molecules. Progress on other applications, including controlling photodissociation processes, isotope separation, stabilization of molecular Bose-Einstein condensates as well as applications to biological molecules also be presented. *Support acknowledged from EPSRC.

Obesity Among U.S.- and Foreign-Born Blacks by Region of Birth.

PubMed

Mehta, Neil K; Elo, Irma T; Ford, Nicole D; Siegel, Karen R

2015-08-01

Large, recent migration streams from the non-Hispanic Caribbean islands and Africa have increased the share of U.S. blacks born outside of the U.S. Little is known about health patterns in these foreign-born populations. The purpose of this study is to compare obesity levels among self-identified U.S. blacks across birth regions and examine potential explanations for subgroup differences. Data were from the 2000-2013 National Health Interview Surveys. Three birthplace subgroups were examined: individuals born in the U.S., Caribbean/South America, and Africa, aged 25-59 years. Data were analyzed in 2013-2014. Compared to U.S.-born participants, foreign-born participants had significantly lower obesity (BMI ≥30) odds. The AORs were 0.51 (Caribbean/South American-born, 95% CI=0.44, 0.58) and 0.41 (African-born, 95% CI=0.34, 0.50) with reference to U.S.-born individuals. Education, income, and cigarette smoking did not explain the favorable weight pattern of the foreign born. Among the foreign born, those residing in the U.S. for ≥15 years had 51% (95% CI=10%, 108%) higher obesity odds compared with those residing for <5 years. No statistically significant differences in obesity odds between those born in the Caribbean/South America and Africa were detected. Foreign-born blacks generally had lower obesity levels compared to their U.S.-born counterparts, which was not explained by SES or smoking behaviors. Despite this advantage, obesity prevalence among foreign-born black women was around 30%, suggesting that obesity poses a significant health risk this population. Copyright © 2015 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

To what extent may the association between immigrant status and mental illness be explained by socioeconomic factors?

PubMed

Tinghög, Petter; Hemmingsson, Tomas; Lundberg, Ingvar

2007-12-01

Immigrants in Sweden have a higher rate of mental illness than the native Swedes. This study investigated to what extent the association between immigrant status and mental illness can be explained by a different distribution of known risk factors for impaired mental health between groups of immigrants and persons born in Sweden. The study is based on data from the Swedish PART-study, designed to identify risk factors for, and social consequences of, mental illness. The study population consists of a random sample of 10,423 Swedish citizens, whereof 1,109 were immigrants. The data was collected in the year 2000. The immigrants were divided into three groups based on country of origin (Scandinavians born outside Sweden, Europeans born outside Scandinavia, non-Europeans). The occurrence of mental illness among immigrants and native Swedes were compared not adjusting and adjusting for indicators of socioeconomic advantage/disadvantage (education, income, labour market position, etc). Mental illness was approximated with the WHO (ten) wellbeing index scale and depressive symptoms were measured with the major depression inventory scale (MDI). Immigrants' excess risk for low subjective wellbeing was completely accounted for by adjustment for known risk factors in all the immigrant groups. However, social-economic disadvantages could not account for the non-European immigrants' higher prevalence of depression (MDI), although the increased relative risk found in univariate analyses was substantially reduced. The findings in this study suggest that the association between immigrant status and mental illness appears above all to be an effect of a higher prevalence of social and economic disadvantage.

Impact of timing of birth and resident duty-hour restrictions on outcomes for small preterm infants.

PubMed

Bell, Edward F; Hansen, Nellie I; Morriss, Frank H; Stoll, Barbara J; Ambalavanan, Namasivayam; Gould, Jeffrey B; Laptook, Abbot R; Walsh, Michele C; Carlo, Waldemar A; Shankaran, Seetha; Das, Abhik; Higgins, Rosemary D

2010-08-01

The goal was to examine the impact of birth at night, on the weekend, and during July or August (the first months of the academic year) and the impact of resident duty-hour restrictions on mortality and morbidity rates for very low birth weight infants. Outcomes were analyzed for 11,137 infants with birth weights of 501 to 1250 g who were enrolled in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network registry in 2001-2005. Approximately one-half were born before the introduction of resident duty-hour restrictions in 2003. Follow-up assessments at 18 to 22 months were completed for 4508 infants. Mortality rate, short-term morbidities, and neurodevelopmental outcome were examined with respect to the timing of birth. There was no effect of the timing of birth on mortality rate and no impact on the risks of short-term morbidities except that the risk of retinopathy of prematurity (stage > or =2) was higher after the introduction of duty-hour restrictions and the risk of retinopathy of prematurity requiring operative treatment was lower for infants born during the late night than during the day. There was no impact of the timing of birth on neurodevelopmental outcome except that the risk of hearing impairment or death was slightly lower among infants born in July or August. In this network, the timing of birth had little effect on the risks of death and morbidity for very low birth weight infants, which suggests that staffing patterns were adequate to provide consistent care.

Storm time plasma transport in a unified and inter-coupled global magnetosphere model

NASA Astrophysics Data System (ADS)

Ilie, R.; Liemohn, M. W.; Toth, G.

2014-12-01

We present results from the two-way self-consistent coupling between the kinetic Hot Electron and Ion Drift Integrator (HEIDI) model and the Space Weather Modeling Framework (SWMF). HEIDI solves the time dependent, gyration and bounced averaged kinetic equation for the phase space density of different ring current species and computes full pitch angle distributions for all local times and radial distances. During geomagnetic times the dipole approximation becomes unsuitable even in the inner magnetosphere. Therefore the HEIDI model was generalized to accommodate an arbitrary magnetic field and through the coupling with SWMF it obtains a magnetic field description throughout the HEIDI domain along with a plasma distribution at the model outer boundary from the Block Adaptive Tree Solar Wind Roe Upwind Scheme (BATS-R-US) magnetohydrodynamics (MHD) model within SWMF. Electric field self-consistency is assured by the passing of convection potentials from the Ridley Ionosphere Model (RIM) within SWMF. In this study we test the various levels of coupling between the 3 physics based models, highlighting the role that the magnetic field, plasma sheet conditions and the cross polar cap potential play in the formation and evolution of the ring current. We show that the dynamically changing geospace environment itself plays a key role in determining the geoeffectiveness of the driver. The results of the self-consistent coupling between HEIDI, BATS-R-US and RIM during disturbed conditions emphasize the importance of a kinetic self-consistent approach to the description of geospace.

Racial/ethnic disparities in self-reported short sleep duration among US-born and foreign-born adults.

PubMed

Cunningham, Timothy J; Wheaton, Anne G; Ford, Earl S; Croft, Janet B

2016-12-01

Racial/ethnic health disparities are infrequently considered by nativity status in the United States, although the immigrant population has practically doubled since 1990. We investigated the modifying role of nativity status (US- vs. foreign-born) on racial/ethnic disparities in short sleep duration (<7 h), which has serious health consequences. Cross-sectional data from 23,505 US-born and 4,326 foreign-born adults aged ≥ 18 years from the 2012 National Health Interview Survey and multivariable log-linear regression were used to estimate prevalence ratios (PR) for reporting short sleep duration and their corresponding 95% confidence intervals (CI). After controlling for sociodemographic covariates, short sleep was more prevalent among blacks (PR 1.29, 95% CI: 1.21-1.37), Hispanics (PR 1.18, 95% CI: 1.08, 1.29), and Asians (PR 1.37, 95% CI: 1.16-1.61) than whites among US-born adults. Short sleep was more prevalent among blacks (PR 1.71, 95% CI: 1.38, 2.13) and Asians (PR 1.23, 95% CI: 1.02, 1.47) than whites among the foreign-born. Among both US- and foreign-born adults, blacks and Asians had a higher likelihood of short sleep compared to whites. US-born Hispanics, but not foreign-born Hispanics, had a higher likelihood than their white counterparts. Future research should aim to uncover mechanisms underlying these disparities.

First-principles studies of electronic, transport and bulk properties of pyrite FeS2

NASA Astrophysics Data System (ADS)

Banjara, Dipendra; Mbolle, Augustine; Malozovsky, Yuriy; Franklin, Lashounda; Bagayoko, Diola

We present results of ab-initio, self-consistent density functional theory (DFT) calculations of electronic, transport, and bulk properties of pyrite FeS2. We employed a local density approximation (LDA) potential and the linear combination of atomic orbitals (LCAO) formalism, following the Bagayoko, Zhao and Williams (BZW) method, as enhanced by Ekuma and Franklin (BZW-EF). The BZW-EF method requires successive, self consistent calculations with increasing basis sets to reach the ground state of the system under study. We report the band structure, the band gap, total and partial densities of states, effective masses, and the bulk modulus. Work funded in part by the US Department of Energy (DOE), National Nuclear Security Administration (NNSA) (Award No.DE-NA0002630), the National Science Foundation (NSF) (Award No, 1503226), LaSPACE, and LONI-SUBR.

Effects of electronic and lattice polarization on the band structure of delafossite transparent conductive oxides.

PubMed

Vidal, Julien; Trani, Fabio; Bruneval, Fabien; Marques, Miguel A L; Botti, Silvana

2010-04-02

We use hybrid functionals and restricted self-consistent GW, state-of-the-art theoretical approaches for quasiparticle band structures, to study the electronic states of delafossite Cu(Al,In)O2, the first p-type and bipolar transparent conductive oxides. We show that a self-consistent GW approximation gives remarkably wider band gaps than all the other approaches used so far. Accounting for polaronic effects in the GW scheme we recover a very nice agreement with experiments. Furthermore, the modifications with respect to the Kohn-Sham bands are strongly k dependent, which makes questionable the common practice of using a scissor operator. Finally, our results support the view that the low energy structures found in optical experiments, and initially attributed to an indirect transition, are due to intrinsic defects in the samples.

Self-consistent Hartree-Fock RPA calculations in 208Pb

NASA Astrophysics Data System (ADS)

Taqi, Ali H.; Ali, Mohammed S.

2018-01-01

The nuclear structure of 208Pb is studied in the framework of the self-consistent random phase approximation (SCRPA). The Hartree-Fock mean field and single particle states are used to implement a completely SCRPA with Skyrme-type interactions. The Hamiltonian is diagonalised within a model space using five Skyrme parameter sets, namely LNS, SkI3, SkO, SkP and SLy4. In view of the huge number of the existing Skyrme-force parameterizations, the question remains which of them provide the best description of data. The approach attempts to accurately describe the structure of the spherical even-even nucleus 208Pb. To illustrate our approach, we compared the binding energy, charge density distribution, excitation energy levels scheme with the available experimental data. Moreover, we calculated isoscalar and isovector monopole, dipole, and quadrupole transition densities and strength functions.

Polarization transfer observables in elastic electron-proton scattering at Q2=2.5 , 5.2, 6.8, and 8.5 GeV2

NASA Astrophysics Data System (ADS)

Puckett, A. J. R.; Brash, E. J.; Jones, M. K.; Luo, W.; Meziane, M.; Pentchev, L.; Perdrisat, C. F.; Punjabi, V.; Wesselmann, F. R.; Afanasev, A.; Ahmidouch, A.; Albayrak, I.; Aniol, K. A.; Arrington, J.; Asaturyan, A.; Baghdasaryan, H.; Benmokhtar, F.; Bertozzi, W.; Bimbot, L.; Bosted, P.; Boeglin, W.; Butuceanu, C.; Carter, P.; Chernenko, S.; Christy, M. E.; Commisso, M.; Cornejo, J. C.; Covrig, S.; Danagoulian, S.; Daniel, A.; Davidenko, A.; Day, D.; Dhamija, S.; Dutta, D.; Ent, R.; Frullani, S.; Fenker, H.; Frlez, E.; Garibaldi, F.; Gaskell, D.; Gilad, S.; Gilman, R.; Goncharenko, Y.; Hafidi, K.; Hamilton, D.; Higinbotham, D. W.; Hinton, W.; Horn, T.; Hu, B.; Huang, J.; Huber, G. M.; Jensen, E.; Keppel, C.; Khandaker, M.; King, P.; Kirillov, D.; Kohl, M.; Kravtsov, V.; Kumbartzki, G.; Li, Y.; Mamyan, V.; Margaziotis, D. J.; Marsh, A.; Matulenko, Y.; Maxwell, J.; Mbianda, G.; Meekins, D.; Melnik, Y.; Miller, J.; Mkrtchyan, A.; Mkrtchyan, H.; Moffit, B.; Moreno, O.; Mulholland, J.; Narayan, A.; Nedev, S.; Nuruzzaman, Piasetzky, E.; Pierce, W.; Piskunov, N. M.; Prok, Y.; Ransome, R. D.; Razin, D. S.; Reimer, P.; Reinhold, J.; Rondon, O.; Shabestari, M.; Shahinyan, A.; Shestermanov, K.; Širca, S.; Sitnik, I.; Smykov, L.; Smith, G.; Solovyev, L.; Solvignon, P.; Subedi, R.; Tomasi-Gustafsson, E.; Vasiliev, A.; Veilleux, M.; Wojtsekhowski, B. B.; Wood, S.; Ye, Z.; Zanevsky, Y.; Zhang, X.; Zhang, Y.; Zheng, X.; Zhu, L.

2017-11-01

Background: Interest in the behavior of nucleon electromagnetic form factors at large momentum transfers has steadily increased since the discovery, using polarization observables, of the rapid decrease of the ratio GEp/GMp of the proton's electric and magnetic form factors for momentum transfers Q2≳1 GeV2, in strong disagreement with previous extractions of this ratio using the traditional Rosenbluth separation technique. Purpose: The GEp-III and GEp -2 γ experiments were carried out in Jefferson Laboratory's (JLab's) Hall C from 2007 to 2008, to extend the knowledge of GEp/GMp to the highest practically achievable Q2 given the maximum beam energy of 6 GeV and to search for effects beyond the Born approximation in polarization transfer observables of elastic e ⃗p scattering. This article provides an expanded description of the common experimental apparatus and data analysis procedures, and reports the results of a final reanalysis of the data from both experiments, including the previously unpublished results of the full-acceptance dataset of the GEp -2 γ experiment. Methods: Polarization transfer observables in elastic e ⃗p →e p ⃗ scattering were measured at central Q2 values of 2.5, 5.2, 6.8, and 8.54 GeV2. At Q2=2.5 GeV2 , data were obtained for central values of the virtual photon polarization parameter ɛ of 0.149, 0.632, and 0.783. The Hall C High Momentum Spectrometer detected and measured the polarization of protons recoiling elastically from collisions of JLab's polarized electron beam with a liquid hydrogen target. A large-acceptance electromagnetic calorimeter detected the elastically scattered electrons in coincidence to suppress inelastic backgrounds. Results: The final GEp-III data are largely unchanged relative to the originally published results. The statistical uncertainties of the final GEp -2 γ data are significantly reduced at ɛ =0.632 and 0.783 relative to the original publication. Conclusions: The final GEp-III results show that the decrease with Q2 of GEp/GMp continues to Q2=8.5 GeV2 , but at a slowing rate relative to the approximately linear decrease observed in earlier Hall A measurements. At Q2=8.5 GeV2 , GEp/GMp remains positive but is consistent with zero. At Q2=2.5 GeV2 , GEp/GMp derived from the polarization component ratio R ∝Pt/Pℓ shows no statistically significant ɛ dependence, as expected in the Born approximation. On the other hand, the ratio Pℓ/PℓBorn of the longitudinal polarization transfer component to its Born value shows an enhancement of roughly 1.7% at ɛ =0.783 relative to ɛ =0.149 , with ≈2.2 σ significance based on the total uncertainty, implying a similar effect in the transverse component Pt that cancels in the ratio R .

Immigration, citizenship, and the mental health of adolescents

PubMed Central

Fenelon, Andrew; Boudreaux, Michel

2018-01-01

Purpose To examine the reported mental health outcomes of adolescent foreign-born non-citizens and adolescent foreign-born U.S. citizens compared to adolescent U.S.-born citizens. Methods Using the Strengths and Difficulties Questionnaire in the National Health Interview Survey, we compared mental health status of U.S.-born adolescent citizens to foreign-born citizens and non-citizens in the years 2010–2015, and examined how differences in emotional difficulty changed based on time spent in the U.S. Results Results suggest that non-citizen adolescents experience better mental health outcomes than U.S.-born citizens. However, the mental health status of foreign-born citizens is indistinguishable from that of the U.S.-born, after accounting for basic socio-demographic characteristics. The prevalence of emotional difficulty experienced by immigrant adolescents increased with a family’s duration in the U.S. Conclusion Our findings are consistent with a broader health advantage for the foreign-born, but we present new evidence that the mental health advantage of foreign-born adolescents exists only for non-citizens. PMID:29723297

Efficient parallel linear scaling construction of the density matrix for Born-Oppenheimer molecular dynamics.

PubMed

Mniszewski, S M; Cawkwell, M J; Wall, M E; Mohd-Yusof, J; Bock, N; Germann, T C; Niklasson, A M N

2015-10-13

We present an algorithm for the calculation of the density matrix that for insulators scales linearly with system size and parallelizes efficiently on multicore, shared memory platforms with small and controllable numerical errors. The algorithm is based on an implementation of the second-order spectral projection (SP2) algorithm [ Niklasson, A. M. N. Phys. Rev. B 2002 , 66 , 155115 ] in sparse matrix algebra with the ELLPACK-R data format. We illustrate the performance of the algorithm within self-consistent tight binding theory by total energy calculations of gas phase poly(ethylene) molecules and periodic liquid water systems containing up to 15,000 atoms on up to 16 CPU cores. We consider algorithm-specific performance aspects, such as local vs nonlocal memory access and the degree of matrix sparsity. Comparisons to sparse matrix algebra implementations using off-the-shelf libraries on multicore CPUs, graphics processing units (GPUs), and the Intel many integrated core (MIC) architecture are also presented. The accuracy and stability of the algorithm are illustrated with long duration Born-Oppenheimer molecular dynamics simulations of 1000 water molecules and a 303 atom Trp cage protein solvated by 2682 water molecules.

Microscopic theory of the superconducting gap in the quasi-one-dimensional organic conductor (TMTSF) 2ClO4 : Model derivation and two-particle self-consistent analysis

NASA Astrophysics Data System (ADS)

Aizawa, Hirohito; Kuroki, Kazuhiko

2018-03-01

We present a first-principles band calculation for the quasi-one-dimensional (Q1D) organic superconductor (TMTSF) 2ClO4 . An effective tight-binding model with the TMTSF molecule to be regarded as the site is derived from a calculation based on maximally localized Wannier orbitals. We apply a two-particle self-consistent (TPSC) analysis by using a four-site Hubbard model, which is composed of the tight-binding model and an onsite (intramolecular) repulsive interaction, which serves as a variable parameter. We assume that the pairing mechanism is mediated by the spin fluctuation, and the sign of the superconducting gap changes between the inner and outer Fermi surfaces, which correspond to a d -wave gap function in a simplified Q1D model. With the parameters we adopt, the critical temperature for superconductivity estimated by the TPSC approach is approximately 1 K, which is consistent with experiment.

Role of Educational Exposure in the Association Between Myopia and Birth Order.

PubMed

Guggenheim, Jeremy A; Williams, Cathy

2015-12-01

Visual impairment due to myopia is an important public health issue. A prior analysis of population-based cohorts aged 15 to 22 years recruited from the United Kingdom and Israel suggested myopia and high myopia were approximately 10% more common in first-born compared with later-born children. To examine whether myopia was associated with birth order in an earlier generation than studied previously and, if so, whether the association was attenuated after adjusting for education exposure, as predicted by the hypothesis that the education of children with later birth orders is less intense. Cross-sectional study of UK Biobank participants recruited from 2006 to 2010. Analysis was restricted to participants aged 40 to 69 years who had a vision assessment, self-reported white ethnicity, and no history of eye disorders (N = 89,120). Myopia and high myopia were defined as autorefraction of -0.75 diopters (D) or less and -6.00 D or less, respectively. Birth order and information on potential confounders including highest educational qualification ascertained using a structured questionnaire. Odds ratios (ORs) for myopia and high myopia by birth order, using logistic regression and adjusting for age and sex (model 1) or age, sex, and highest educational qualification (model 2). In model 1 (no adjustment for education), birth order was associated with both myopia and high myopia (eg, comparing first- vs second-born individuals; OR, 1.12; 95% CI, 1.08-1.16; P = 1.40E-11 and OR, 1.21; 95% CI, 1.11-1.30; P = 3.60E-06 for myopia and high myopia, respectively). The risk for myopia became progressively lower for later birth orders, suggesting a dose response. In model 2 (after adjusting for education), the effect sizes were attenuated by approximately 25% (OR, 1.09; 95% CI, 1.05-1.12; P = 1.30E-06 and OR, 1.15; 95% CI, 1.06-1.25; P = 4.60E-04 for myopia and high myopia, respectively) and the apparent dose response was abolished. These data suggest that the association between birth order and myopia is not due to a new environmental pressure in the last 30 to 40 years. The attenuated effect size after adjusting for educational exposure supports a role for reduced parental investment in education of children with later birth orders in their relative protection from myopia.

Childhood language skills and adolescent self-esteem in preterm survivors.

PubMed

Islam, Umna A; Poole, Kristie L; Schmidt, Louis A; Ford, Jennifer; Saigal, Saroj; Van Lieshout, Ryan J

2018-03-01

Fifty-seven percent of children with poor language skills are affected by socio-emotional problems. Despite the importance of language skills to interpersonal functioning and school performance, relatively little is known about how they affect self-esteem in adolescence. Data on youth at high risk for language problems (e.g. those born extremely low birth weight (ELBW; <1000 grams)) are even more scarce. This prospective study examined associations between language skills at age 8 and self-esteem during adolescence (12-16 years) in individuals born at ELBW ( N = 138) or normal birth weight (NBW; >2500 grams) ( N = 111). Participants' language skills were assessed using the Verbal Scale of the Wechsler Intelligence Scale for Children-Revised and the Token Test at age 8. In adolescence, participants completed the Harter Self-Perception Profile for Adolescents. Birth weight status was found to moderate associations between childhood language and adolescent global self-esteem (Token Test ( p = .006), Verbal Intelligence Quotient ( p = .033)) such that better language skills were associated with higher self-esteem in adolescent ELBW survivors, but not in NBW participants. Language skills may play a protective role in the development and maintenance of self-esteem in ELBW youth and could be an important target for optimizing their functioning, particularly before transitioning to the critical adolescent period.

[Self-concept of school-age children: the norm in Kaohsiung].

PubMed

Chin, C C; Liu, Y Y; Ka, J K

1989-05-01

This study has two objectives: (1) to establish the norm of three graphical projective tests (Children's Social-Self Test, Children's Attitude Inventory and Children's Self-Concept Inventory), and (2) to explore the influence of sex, order of birth, social economic status of family, and leadership of class that effect self-concept of the school-age children. These subjects are selected from elementary schools in Kaohsiung, twenty-two classes are drawn out from each grade by systemic-random sampling. Then two classes are drawn out from 22 classes at random to arrange retest for reliability. The total subjects are 6207 students. From October 1987 to June 1988, six researchers are divided into three group to conduct the test. Besides establishing the norm, we find results from analysis of data as follow: 1. The reliability and validity of three graphical projective tests are good, they can be used for assessing the self-concept of school-age children. 2. The grade, sex, order of birth, social economic status of family, leadership of class all influence the self-concept of school-age children. 3. The self-concept and the grade has negative correlation. 4. The self-concept and the social economic status of family has positive correlation. 5. The girls have higher self-concept than the boys. 6. The order of first-born or second-born has higher self-concept than the others. 7. The ones who are leaders of class have higher self-concept than the others.

Dietary intakes and health-related behaviours of Korean American women born in the USA and Korea: the Multiethnic Cohort Study.

PubMed

Park, Song-Yi; Murphy, Suzanne P; Sharma, Sangita; Kolonel, Laurence N

2005-10-01

This study assessed and compared heath-related behaviours and nutrient and food group intakes between US-born and Korea-born Korean American women. Cross-sectional analyses were performed for ethnic Koreans who participated in the Multiethnic Cohort Study in Hawaii and Los Angeles in 1993-1996. The sample included 492 Korean American women aged 45-75 years who were born in the USA (n = 274) or Korea (n = 218). Participants were recruited using driver's license files as a primary sampling source and completed a self-administered questionnaire, including a quantitative food frequency section. The proportion overweight or obese was 31.4% in US-born and 9.4% in Korea-born women. US-born women had higher intakes of total fat and fat as a percentage of energy, and lower intakes of sodium, vitamin C, beta-carotene and carbohydrate as a percentage of energy, than Korea-born women. Comparing intakes of food group servings from the Food Guide Pyramid, US-born women reported more whole grains, red meat and nuts, and less soy products, than did Korea-born women. US-born women also consumed fewer vegetables and fruit than those born in Korea. Few women in either group reported intakes that met the recommendations for dairy foods. Intake of discretionary fat from the Pyramid tip was higher in US-born than in Korea-born women. These findings indicate that the acculturation of Korean immigrants affects dietary intakes in ways that may alter risks of several chronic diseases. Further studies will be necessary to examine the effects of dietary acculturation on disease patterns.

Fractal structure of the interplanetary magnetic field

NASA Technical Reports Server (NTRS)

Burlaga, L. F.; Klein, L. W.

1985-01-01

Under some conditions, time series of the interplanetary magnetic field strength and components have the properties of fractal curves. Magnetic field measurements made near 8.5 AU by Voyager 2 from June 5 to August 24, 1981 were self-similar over time scales from approximately 20 sec to approximately 3 x 100,000 sec, and the fractal dimension of the time series of the strength and components of the magnetic field was D = 5/3, corresponding to a power spectrum P(f) approximately f sup -5/3. Since the Kolmogorov spectrum for homogeneous, isotropic, stationary turbulence is also f sup -5/3, the Voyager 2 measurements are consistent with the observation of an inertial range of turbulence extending over approximately four decades in frequency. Interaction regions probably contributed most of the power in this interval. As an example, one interaction region is discussed in which the magnetic field had a fractal dimension D = 5/3.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franović, Igor, E-mail: franovic@ipb.ac.rs; Todorović, Kristina; Burić, Nikola

We use the mean-field approach to analyze the collective dynamics in macroscopic networks of stochastic Fitzhugh-Nagumo units with delayed couplings. The conditions for validity of the two main approximations behind the model, called the Gaussian approximation and the Quasi-independence approximation, are examined. It is shown that the dynamics of the mean-field model may indicate in a self-consistent fashion the parameter domains where the Quasi-independence approximation fails. Apart from a network of globally coupled units, we also consider the paradigmatic setup of two interacting assemblies to demonstrate how our framework may be extended to hierarchical and modular networks. In both cases,more » the mean-field model can be used to qualitatively analyze the stability of the system, as well as the scenarios for the onset and the suppression of the collective mode. In quantitative terms, the mean-field model is capable of predicting the average oscillation frequency corresponding to the global variables of the exact system.« less

Risk groups in children under six months of age using self-organizing maps.

PubMed

Schilithz, A O C; Kale, P L; Gama, S G N; Nobre, F F

2014-06-01

Fetal and infant growth tends to follow irregular patterns and, particularly in developing countries, these patterns are greatly influenced by unfavorable living conditions and interactions with complications during pregnancy. The aim of this study was to identify groups of children with different risk profiles for growth development. The study sample comprised 496 girls and 508 boys under six months of age from 27 pediatric primary health care units in the city of Rio de Janeiro, Brazil. Data were obtained through interviews with the mothers and by reviewing each child's health card. An unsupervised learning, know as a self-organizing map (SOM) and a K-means algorithm were used for cluster analysis to identify groups of children. Four groups of infants were identified. The first (139) consisted of infants born exclusively by cesarean delivery, and their mothers were exclusively multiparous; the highest prevalences of prematurity and low birthweight, a high prevalence of exclusive breastfeeding and a low proportion of hospitalization were observed for this group. The second (247 infants) and the third (298 infants) groups had the best and worst perinatal and infant health indicators, respectively. The infants of the fourth group (318) were born heavier, had a low prevalence of exclusive breastfeeding, and had a higher rate of hospitalization. Using a SOM, it was possible to identify children with common features, although no differences between groups were found with respect to the adequacy of postnatal weight. Pregnant women and children with characteristics similar to those of group 3 require early intervention and more attention in public policy. Copyright © 2014. Published by Elsevier Ireland Ltd.

Foreign-Born Therapists: How Acculturation and Supervisors' Multicultural Competence Are Associated with Clinical Self-Efficacy

ERIC Educational Resources Information Center

Kissil, Karni; Davey, Maureen; Davey, Adam

2015-01-01

The authors examined the associations between acculturation, supervisors' multicultural competence, and clinicians' self-efficacy in a sample of 153 immigrant therapists currently practicing in the United States. Participants completed a demographic questionnaire and 3 additional questionnaires that examined their levels of…

Building Cultural Capability for Full-Spectrum Operations

DTIC Science & Technology

2008-01-01

Mol, Born, Willemsen, & Van der Molen , 2005; Caligiuri & Day, 2000). In addition to these broad traits, antecedents to cross-cultural competence...510-517. 18 Mol, S. T., Born, M. P., Willemsen, M. E., & Van Der Molen , H. T. (2005). Predicting expatriate job performance for selection purposes: A...et al., 2003). In addition, self-regulation has been shown to be critical for adjustment (Matsumoto et al., 2003; van Oudenhoven, Mol, & Van der Zee

Eastern Equine Encephalitis

MedlinePlus

... EEE is one of the most severe mosquito-transmitted diseases in the United States with approximately 33% mortality ... Emerging and Zoonotic Infectious Diseases (NCEZID) Division of Vector-Borne Diseases (DVBD) Email Recommend Tweet YouTube Instagram Listen Watch ...

Electron impact excitation of H2 - Rydberg band systems and the benchmark dissociative cross section for H Lyman-alpha

NASA Technical Reports Server (NTRS)

Shemansky, D. E.; Hall, D. T.; Ajello, J. M.

1985-01-01

The cross sections sigma R 1 (2p) for excitation of H Ly-alpha emission produced by electron impact on H2 is reexamined. A more accurate estimate for sigma R 1 (2p) is obtained based on Born approximation estimates of the H2 Rydberg system cross sections using measured relative excitation functions. The obtained value is (8.18 + or -1.2) x 10 to the -18th sq cm at 100 eV, a factor of 0.69 below the value universally applied to cross section measurements over the past decade. Cross sections for the H2 Rydberg systems fixed in magnitude by the Born approximation have also been obtained using experimentally determined excitation functions. Accurate analytic expressions for these cross sections allow the direct calculation of rate coefficients.

Quantitative assessment of submicron scale anisotropy in tissue multifractality by scattering Mueller matrix in the framework of Born approximation

NASA Astrophysics Data System (ADS)

Das, Nandan Kumar; Dey, Rajib; Chakraborty, Semanti; Panigrahi, Prasanta K.; Meglinski, Igor; Ghosh, Nirmalya

2018-04-01

A number of tissue-like disordered media exhibit local anisotropy of scattering in the scaling behavior. Scaling behavior contains wealth of fractal or multifractal properties. We demonstrate that the spatial dielectric fluctuations in a sample of biological tissue exhibit multifractal anisotropy. Multifractal anisotropy encoded in the wavelength variation of the light scattering Mueller matrix and manifesting as an intriguing spectral diattenuation effect. We developed an inverse method for the quantitative assessment of the multifractal anisotropy. The method is based on the processing of relevant Mueller matrix elements in Fourier domain by using Born approximation, followed by the multifractal analysis. The approach promises for probing subtle micro-structural changes in biological tissues associated with the cancer and precancer, as well as for non-destructive characterization of a wide range of scattering materials.

Single electron impact ionization of the methane molecule

NASA Astrophysics Data System (ADS)

Bouamoud, Mammar; Sahlaoui, Mohammed; Benmansour, Nour El Houda; Atomic and Molecular Collisions Team

2014-10-01

Triply differential cross sections (TDCS) results of electron-impact ionization of the inner 2a1 molecular orbital of CH4 are presented in the framework of the Second Born Approximation and compared with the experimental data performed in coplanar asymmetric geometry. The cross sections are averaged on the random orientations of the molecular target for accurate comparison with experiments and are compared also with the theoretical calculations of the Three Coulomb wave (3CW) model. Our results are in good agreement with experiments and 3CW results in the binary peak. In contrast the Second Born Approximation yields a significant higher values compared to the 3CW results for the recoil peak and seems to describe suitably the recoil region where higher order effects can occur with the participation of the recoiling ion in the collision process.

Precise calculations in simulations of the interaction of low energy neutrons with nano-dispersed media

NASA Astrophysics Data System (ADS)

Artem'ev, V. A.; Nezvanov, A. Yu.; Nesvizhevsky, V. V.

2016-01-01

We discuss properties of the interaction of slow neutrons with nano-dispersed media and their application for neutron reflectors. In order to increase the accuracy of model simulation of the interaction of neutrons with nanopowders, we perform precise quantum mechanical calculation of potential scattering of neutrons on single nanoparticles using the method of phase functions. We compare results of precise calculations with those performed within first Born approximation for nanodiamonds with the radius of 2-5 nm and for neutron energies 3 × 10-7-10-3 eV. Born approximation overestimates the probability of scattering to large angles, while the accuracy of evaluation of integral characteristics (cross sections, albedo) is acceptable. Using Monte-Carlo method, we calculate albedo of neutrons from different layers of piled up diamond nanopowder.

Branes in Extended Spacetime: Brane Worldvolume Theory Based on Duality Symmetry.

PubMed

Sakatani, Yuho; Uehara, Shozo

2016-11-04

We propose a novel approach to the brane worldvolume theory based on the geometry of extended field theories: double field theory and exceptional field theory. We demonstrate the effectiveness of this approach by showing that one can reproduce the conventional bosonic string and membrane actions, and the M5-brane action in the weak-field approximation. At a glance, the proposed 5-brane action without approximation looks different from the known M5-brane actions, but it is consistent with the known nonlinear self-duality relation, and it may provide a new formulation of a single M5-brane action. Actions for exotic branes are also discussed.

Constraint on the second functional derivative of the exchange-correlation energy

NASA Astrophysics Data System (ADS)

Joubert, D. P.

2012-09-01

Using the density functional adiabatic connection approach for an N-electron system it is shown that ? γ is the coupling constant that scales the electron-electron interaction strength. For the non-interacting Kohn-Sham Hamiltonian γ = 0 and for the fully interacting system γ = 1. ? is the Hartree plus exchange-correlation energy while f 0(r) and fγ(r) are the Fukui functions of the non-interacting and interacting systems, respectively. This identity can serve to test the internal self-consistency or quality of approximate functionals. The quality of some popular approximate exchange and correlation functionals are tested for a simple model system.

Bulk and surface electronic structures of MgO

NASA Astrophysics Data System (ADS)

Schönberger, U.; Aryasetiawan, F.

1995-09-01

The bulk electronic structure of MgO is calculated from first principles including correlation effects within the GW approximation. The band gap, the position of the 2s O band, and the valence band width are in good agreement with experiment. From the quasiparticle band structure, optical transitions corresponding to the main optical absorption peaks are identified. The energy-loss spectrum is also calculated and compared with experiment. The surface electronic structure of MgO(100) is calculated self-consistently within the local-density approximation. It is found that states observed in a recent photoemission experiment outside the bulk allowed states are close to surface states.

Photons in dense nuclear matter: Random-phase approximation

NASA Astrophysics Data System (ADS)

Stetina, Stephan; Rrapaj, Ermal; Reddy, Sanjay

2018-04-01

We present a comprehensive and pedagogic discussion of the properties of photons in cold and dense nuclear matter based on the resummed one-loop photon self-energy. Correlations among electrons, muons, protons, and neutrons in β equilibrium that arise as a result of electromagnetic and strong interactions are consistently taken into account within the random phase approximation. Screening effects, damping, and collective excitations are systematically studied in a fully relativistic setup. Our study is relevant to the linear response theory of dense nuclear matter, calculations of transport properties of cold dense matter, and investigations of the production and propagation of hypothetical vector bosons such as the dark photons.

Characterization of Thin Film Materials using SCAN meta-GGA, an Accurate Nonempirical Density Functional

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buda, I. G.; Lane, C.; Barbiellini, B.

We discuss self-consistently obtained ground-state electronic properties of monolayers of graphene and a number of ’beyond graphene’ compounds, including films of transition-metal dichalcogenides (TMDs), using the recently proposed strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation (meta-GGA) to the density functional theory. The SCAN meta-GGA results are compared with those based on the local density approximation (LDA) as well as the generalized gradient approximation (GGA). As expected, the GGA yields expanded lattices and softened bonds in relation to the LDA, but the SCAN meta-GGA systematically improves the agreement with experiment. Our study suggests the efficacy of the SCAN functionalmore » for accurate modeling of electronic structures of layered materials in high-throughput calculations more generally.« less

Characterization of Thin Film Materials using SCAN meta-GGA, an Accurate Nonempirical Density Functional

DOE PAGES

Buda, I. G.; Lane, C.; Barbiellini, B.; ...

2017-03-23

We discuss self-consistently obtained ground-state electronic properties of monolayers of graphene and a number of ’beyond graphene’ compounds, including films of transition-metal dichalcogenides (TMDs), using the recently proposed strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation (meta-GGA) to the density functional theory. The SCAN meta-GGA results are compared with those based on the local density approximation (LDA) as well as the generalized gradient approximation (GGA). As expected, the GGA yields expanded lattices and softened bonds in relation to the LDA, but the SCAN meta-GGA systematically improves the agreement with experiment. Our study suggests the efficacy of the SCAN functionalmore » for accurate modeling of electronic structures of layered materials in high-throughput calculations more generally.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Starrett, C. E.; Saumon, D.

Here, we present an approximation for calculating the equation of state (EOS) of warm and hot dense matter that is built on the previously published pseudoatom molecular dynamics (PAMD) model of dense plasmas [Starrett et al., Phys. Rev. E 91, 013104 (2015)]. And while the EOS calculation with PAMD was previously limited to orbital-free density functional theory (DFT), the new approximation presented here allows a Kohn-Sham DFT treatment of the electrons. The resulting EOS thus includes a quantum mechanical treatment of the electrons with a self-consistent model of the ionic structure, while remaining tractable at high temperatures. The method ismore » validated by comparisons with pressures from ab initio simulations of Be, Al, Si, and Fe. The EOS in the Thomas-Fermi approximation shows remarkable thermodynamic consistency over a wide range of temperatures for aluminum. We also calculate the principal Hugoniots of aluminum and silicon up to 500 eV. We find that the ionic structure of the plasma has a modest effect that peaks at temperatures of a few eV and that the features arising from the electronic structure agree well with ab initio simulations.« less

Electronic excitation of molecules in solution calculated using the symmetry-adapted cluster–configuration interaction method in the polarizable continuum model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fukuda, Ryoichi, E-mail: fukuda@ims.ac.jp; Ehara, Masahiro; Elements Strategy Initiative for Catalysts and Batteries

2015-12-31

The effects from solvent environment are specific to the electronic states; therefore, a computational scheme for solvent effects consistent with the electronic states is necessary to discuss electronic excitation of molecules in solution. The PCM (polarizable continuum model) SAC (symmetry-adapted cluster) and SAC-CI (configuration interaction) methods are developed for such purposes. The PCM SAC-CI adopts the state-specific (SS) solvation scheme where solvent effects are self-consistently considered for every ground and excited states. For efficient computations of many excited states, we develop a perturbative approximation for the PCM SAC-CI method, which is called corrected linear response (cLR) scheme. Our test calculationsmore » show that the cLR PCM SAC-CI is a very good approximation of the SS PCM SAC-CI method for polar and nonpolar solvents.« less

Self-consistent generalized Langevin-equation theory for liquids of nonspherically interacting particles.

PubMed

Elizondo-Aguilera, L F; Zubieta Rico, P F; Ruiz-Estrada, H; Alarcón-Waess, O

2014-11-01

A self-consistent generalized Langevin-equation theory is proposed to describe the self- and collective dynamics of a liquid of linear Brownian particles. The equations of motion for the spherical harmonics projections of the collective and self-intermediate-scattering functions, F_{lm,lm}(k,t) and F_{lm,lm}^{S}(k,t), are derived as a contraction of the description involving the stochastic equations of the corresponding tensorial one-particle density n_{lm}(k,t) and the translational (α=T) and rotational (α=R) current densities j_{lm}^{α}(k,t). Similar to the spherical case, these dynamic equations require as an external input the equilibrium structural properties of the system contained in the projections of the static structure factor, denoted by S_{lm,lm}(k). Complementing these exact equations with simple (Vineyard-like) approximate relations for the collective and the self-memory functions we propose a closed self-consistent set of equations for the dynamic properties involved. In the long-time asymptotic limit, these equations become the so-called bifurcation equations, whose solutions (the nonergodicity parameters) can be written, extending the spherical case, in terms of one translational and one orientational scalar dynamic order parameter, γ_{T} and γ_{R}, which characterize the possible dynamical arrest transitions of the system. As a concrete illustrative application of this theory we determine the dynamic arrest diagram of the dipolar hard-sphere fluid. In qualitative agreement with mode coupling theory, the present self-consistent equations also predict three different regions in the state space spanned by the macroscopic control parameters η (volume fraction) and T* (scaled temperature): a region of fully ergodic states, a region of mixed states, in which the translational degrees of freedom become arrested while the orientational degrees of freedom remain ergodic, and a region of fully nonergodic states.

Transmutation approximations for the application of hybrid Monte Carlo/deterministic neutron transport to shutdown dose rate analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biondo, Elliott D.; Wilson, Paul P. H.

In fusion energy systems (FES) neutrons born from burning plasma activate system components. The photon dose rate after shutdown from resulting radionuclides must be quantified. This shutdown dose rate (SDR) is calculated by coupling neutron transport, activation analysis, and photon transport. The size, complexity, and attenuating configuration of FES motivate the use of hybrid Monte Carlo (MC)/deterministic neutron transport. The Multi-Step Consistent Adjoint Driven Importance Sampling (MS-CADIS) method can be used to optimize MC neutron transport for coupled multiphysics problems, including SDR analysis, using deterministic estimates of adjoint flux distributions. When used for SDR analysis, MS-CADIS requires the formulation ofmore » an adjoint neutron source that approximates the transmutation process. In this work, transmutation approximations are used to derive a solution for this adjoint neutron source. It is shown that these approximations are reasonably met for typical FES neutron spectra and materials over a range of irradiation scenarios. When these approximations are met, the Groupwise Transmutation (GT)-CADIS method, proposed here, can be used effectively. GT-CADIS is an implementation of the MS-CADIS method for SDR analysis that uses a series of single-energy-group irradiations to calculate the adjoint neutron source. For a simple SDR problem, GT-CADIS provides speedups of 200 100 relative to global variance reduction with the Forward-Weighted (FW)-CADIS method and 9 ± 5 • 104 relative to analog. As a result, this work shows that GT-CADIS is broadly applicable to FES problems and will significantly reduce the computational resources necessary for SDR analysis.« less

Transmutation approximations for the application of hybrid Monte Carlo/deterministic neutron transport to shutdown dose rate analysis

DOE PAGES

Biondo, Elliott D.; Wilson, Paul P. H.

2017-05-08

In fusion energy systems (FES) neutrons born from burning plasma activate system components. The photon dose rate after shutdown from resulting radionuclides must be quantified. This shutdown dose rate (SDR) is calculated by coupling neutron transport, activation analysis, and photon transport. The size, complexity, and attenuating configuration of FES motivate the use of hybrid Monte Carlo (MC)/deterministic neutron transport. The Multi-Step Consistent Adjoint Driven Importance Sampling (MS-CADIS) method can be used to optimize MC neutron transport for coupled multiphysics problems, including SDR analysis, using deterministic estimates of adjoint flux distributions. When used for SDR analysis, MS-CADIS requires the formulation ofmore » an adjoint neutron source that approximates the transmutation process. In this work, transmutation approximations are used to derive a solution for this adjoint neutron source. It is shown that these approximations are reasonably met for typical FES neutron spectra and materials over a range of irradiation scenarios. When these approximations are met, the Groupwise Transmutation (GT)-CADIS method, proposed here, can be used effectively. GT-CADIS is an implementation of the MS-CADIS method for SDR analysis that uses a series of single-energy-group irradiations to calculate the adjoint neutron source. For a simple SDR problem, GT-CADIS provides speedups of 200 100 relative to global variance reduction with the Forward-Weighted (FW)-CADIS method and 9 ± 5 • 104 relative to analog. As a result, this work shows that GT-CADIS is broadly applicable to FES problems and will significantly reduce the computational resources necessary for SDR analysis.« less

Patterns of residential crowding among Hispanics in later life: immigration, assimilation, and housing market factors.

PubMed

Burr, Jeffrey A; Mutchler, Jan E; Gerst, Kerstin

2010-11-01

We describe patterns of residential crowding among older Hispanics and non-Hispanic Whites. We also examine hypotheses about the relationship of residential crowding with assimilation (language and duration of residence) and housing market characteristics. We employ a multilevel research design, using data from the 2000 U.S. Census of Population. Hierarchical linear models are utilized to estimate the association between residential crowding and both individual and housing market factors. Approximately one third of older Hispanics in metropolitan areas live in crowded housing compared with only one tenth of older non-Hispanic Whites. Foreign-born older persons report higher levels of crowding than U.S.-born older persons. Residential crowding differences between older Hispanics and non-Hispanics are not eliminated after controls are included. Older Hispanics who report better English language skills and a longer duration of residence in the United States live in less crowded housing. We do not find evidence for a relationship between crowding and residential segregation, but we find consistent evidence for an association between residential crowding and relative size of the Hispanic population. The forces that shape household composition and access to housing among older Hispanics appear to result in higher levels of residential crowding for this population.

Twins less frequent than expected among male births in risk averse populations.

PubMed

Karasek, Deborah; Goodman, Julia; Gemmill, Alison; Falconi, April; Hartig, Terry; Magganas, Aristotle; Catalano, Ralph

2015-06-01

Male twin gestations exhibit higher incidence of fetal morbidity and mortality than singleton gestations. From an evolutionary perspective, the relatively high rates of infant and child mortality among male twins born into threatening environments reduce the fitness of these gestations, making them more vulnerable to fetal loss. Women do not perceive choosing to spontaneously abort gestations although the outcome may result from estimates, made without awareness, of the risks of continuing a pregnancy. Here, we examine whether the non-conscious decisional biology of gestation can be linked to conscious risk aversion. We test this speculation by measuring the association between household surveys in Sweden that gauge financial risk aversion in the population and the frequency of twins among live male births. We used time-series regression methods to estimate our suspected associations and Box-Jenkins modeling to ensure that autocorrelation did not confound the estimation or reduce its efficiency. We found, consistent with theory, that financial risk aversion in the population correlates inversely with the odds of a twin among Swedish males born two months later. The odds of a twin among males fell by approximately 3.5% two months after unexpectedly great risk aversion in the population. This work implies that shocks that affect population risk aversion carry implications for fetal loss in vulnerable twin pregnancies.

Immigration, race/ethnicity, and social and economic factors as predictors of breastfeeding initiation.

PubMed

Celi, Ann C; Rich-Edwards, Janet W; Richardson, Marcie K; Kleinman, Ken P; Gillman, Matthew W

2005-03-01

To determine the impact of immigration status as well as race/ethnicity and social and economic factors on breastfeeding initiation. Cohort. Multisite group practice in eastern Massachusetts. One thousand eight hundred twenty-nine pregnant women prospectively followed up in Project Viva. Whether the participant breastfed her infant. The overall breastfeeding initiation rate was 83%. In multivariate models that included race/ethnicity and social, economic, and demographic factors, foreign-born women were more likely to initiate breastfeeding than US-born women (odds ratio [OR], 3.2 [95% confidence interval (CI), 2.0-5.2]). In models stratified by both race/ethnicity and immigration status, and further adjusted for whether the mother herself was breastfed as an infant and the mother's parents' immigration status, US-born and foreign-born black and Hispanic women initiated breastfeeding at rates at least as high as US-born white women (US-born black vs US-born white women, OR, 1.2 [95% CI, 0.8-1.9], US-born Hispanic vs US-born white women, OR, 1.1 [95% CI, 0.6-1.9], foreign-born black vs US-born white women, OR, 2.6 [95% CI, 1.1-6.0], and foreign-born Hispanic vs US-born white women, OR, 1.8 [95% CI, 0.7-4.8]). Calculations of predicted prevalences showed that, for example, the 2.6-fold increase in odds for the foreign-born black vs US-born white women translated to an increase in probability of approximately 1.4. Higher maternal education and household income also predicted higher initiation rates. Immigration status was strongly associated with increased breastfeeding initiation in this cohort, implying that cultural factors are important in the decision to breastfeed. Immigrants of all races/ethnicities initiated breastfeeding more often than their US-born counterparts. In addition, US-born minority groups initiated breastfeeding at rates at least as high as their white counterparts, likely due in part to high levels of education and income as well as to access to a medical care system that explicitly supports breastfeeding.

Fast inverse scattering solutions using the distorted Born iterative method and the multilevel fast multipole algorithm

PubMed Central

Hesford, Andrew J.; Chew, Weng C.

2010-01-01

The distorted Born iterative method (DBIM) computes iterative solutions to nonlinear inverse scattering problems through successive linear approximations. By decomposing the scattered field into a superposition of scattering by an inhomogeneous background and by a material perturbation, large or high-contrast variations in medium properties can be imaged through iterations that are each subject to the distorted Born approximation. However, the need to repeatedly compute forward solutions still imposes a very heavy computational burden. To ameliorate this problem, the multilevel fast multipole algorithm (MLFMA) has been applied as a forward solver within the DBIM. The MLFMA computes forward solutions in linear time for volumetric scatterers. The typically regular distribution and shape of scattering elements in the inverse scattering problem allow the method to take advantage of data redundancy and reduce the computational demands of the normally expensive MLFMA setup. Additional benefits are gained by employing Kaczmarz-like iterations, where partial measurements are used to accelerate convergence. Numerical results demonstrate both the efficiency of the forward solver and the successful application of the inverse method to imaging problems with dimensions in the neighborhood of ten wavelengths. PMID:20707438

Impact of Neighborhood Environments on Health Consciousness, Information Seeking, and Attitudes among US-Born and Non-US-Born Free Clinic Patients.

PubMed

Kamimura, Akiko; Ashby, Jeanie; Jess, Allison; Trinh, Ha Ngoc; Nourian, Maziar M; Finlayson, Sarah Yukie; Prudencio, Liana; Reel, Justine J

2015-12-01

This study examined the impact of neighborhood environments on health consciousness, information seeking, and attitudes among uninsured free clinic patients to better understand the specific needs of the population for health promotion and prevention efforts. US-born English-speaking, non-US-born English-speaking, and Spanish-speaking free clinic patients completed a self-administered survey using reliable measures in autumn 2014 (N = 769). The results of this study suggest that social cohesion is positively associated with health consciousness, information seeking, and attitudes. Lower levels of available healthy food in the community were associated with higher levels of health consciousness. Although Spanish speakers reported lower levels of the availability of healthy food, social cohesion, and access to the Internet or text messaging compared with US-born or non-US-born English speakers, they were more likely to be health conscious and have higher levels of health information seeking. Spanish speakers as well as non-US-born English speakers, were more likely to attend health education classes compared with US-born English speakers. Health education programs for free clinic patients should include strategies to increase social cohesion. Health education programs should consider the diverse needs of these individual populations to maximize the effectiveness of the programs for free clinic patients.

A Comparison of Self-reported Medication Adherence to Concordance Between Part D Claims and Medication Possession.

PubMed

Savitz, Samuel T; Stearns, Sally C; Zhou, Lei; Thudium, Emily; Alburikan, Khalid A; Tran, Richard; Rodgers, Jo E

2017-05-01

Medicare Part D claims indicate medication purchased, but people who are not fully adherent may extend prescription use beyond the interval prescribed. This study assessed concordance between Part D claims and medication possession at a study visit in relation to self-reported medication adherence. We matched Part D claims for 6 common medications to medications brought to a study visit in 2011-2013 for the Atherosclerosis Risk in Communities study. The combined data consisted of 3027 medication events (claims, medications possessed, or both) for 2099 Atherosclerosis Risk in Communities study participants. Multinomial logistic regression estimated the association of concordance (visit only, Part D only, or both) with self-reported medication adherence while controlling for sociodemographic characteristics, veteran status, and availability under Generic Drug Discount Programs. Relative to participants with high adherence, medication events for participants with low adherence were approximately 25 percentage points less likely to match and more likely to be visit only (P<0.001). The results were similar but smaller in magnitude (approximately 2-3 percentage points) for participants with medium adherence. Compared with females, medication events for male veterans were approximately 11 percentage points less likely to match and more likely to be visit only. Events for medications available through Generic Drug Discount Programs were 3 percentage points more likely to be visit only. Part D claims were substantially less likely to be concordant with medications possessed at study visit for participants with low self-reported adherence. This result supports the construction of adherence proxies such as proportion days covered using Part D claims.

Electronic structures of of PuX (X=S, Se, Te)

NASA Astrophysics Data System (ADS)

Maehira, Takahiro; Sakai, Eijiro; Tatetsu, Yasutomi

2013-08-01

We have calculated the energy band structures and the Fermi surfaces of PuS, PuSe, and PuTe by using a self-consistent relativistic linear augmented-plane-wave method with the exchange and correlation potential in the local density approximation. In general, the energy bands near the Fermi level are mainly caused by the hybridization between the Pu 5 f and the monochalcogenide p electrons. The obtained main Fermi surfaces consisted of two hole sheets and one electron sheet, which were constructed from the band having both the Pu 5 f state and the monochalcogenide p state.

The tight binding model study of the role of band filling on the charge gap in graphene-on-substrate in paramagnetic state

NASA Astrophysics Data System (ADS)

Panda, Rudrashish; Sahu, Sivabrata; Rout, G. C.

2017-05-01

We communicate here a tight binding theoretical model study of the band filling effect on the charge gap in graphene-on-substrate. The Hamiltonian consists of nearest neighbor electron hopping and substrate induced gap. Besides this the Coulomb interaction is considered here within mean-field approximation in the paramagnetic limit. The electron occupancies at two sublattices are calculated by Green's function technique and are solved self consistently. Finally the charge gap i.e. Δ ¯=U [ < na > -< nb > ] is calculated and computed numerically. The results are reported.

A differential equation for the Generalized Born radii.

PubMed

Fogolari, Federico; Corazza, Alessandra; Esposito, Gennaro

2013-06-28

The Generalized Born (GB) model offers a convenient way of representing electrostatics in complex macromolecules like proteins or nucleic acids. The computation of atomic GB radii is currently performed by different non-local approaches involving volume or surface integrals. Here we obtain a non-linear second-order partial differential equation for the Generalized Born radius, which may be solved using local iterative algorithms. The equation is derived under the assumption that the usual GB approximation to the reaction field obeys Laplace's equation. The equation admits as particular solutions the correct GB radii for the sphere and the plane. The tests performed on a set of 55 different proteins show an overall agreement with other reference GB models and "perfect" Poisson-Boltzmann based values.

Local moment relaxation in heavy-fermion compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simanek, E.; Sasahara, K.

1987-02-01

The Korringa relaxation rate for a local moment of an impurity in a heavy fermion compound is calculated using the model of Yoshimori and Kasai. Consistent with the recent ESR data for local moments in UBe/sub 13/, the relaxation rate is found to be unaffected by the heavy fermion renormalizations. This result can be traced to the single-site approximation and the weak k dependence of the conduction electron self-energy.

Wave fluctuations in the system with some Yang-Mills condensates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prokhorov, G., E-mail: zhoraprox@yandex.ru; Pasechnik, R., E-mail: Roman.Pasechnik@thep.lu.se; Vereshkov, G., E-mail: gveresh@gmail.com

2016-12-15

Self-consistent dynamics of non-homogeneous fluctuations and homogeneous and isotropic condensate of Yang–Mills fields was investigated in zero, linear and quasilinear approximations over the wave modes in the framework of N = 4 supersymmetric model in Hamilton gauge in quasiclassical theory. The models with SU(2), SU(3) and SU(4) gauge groups were considered. Particle production effect and effect of generation of longitudinal oscillations were obtained.

Disorder and superfluid density in overdoped cuprate superconductors

NASA Astrophysics Data System (ADS)

Lee-Hone, N. R.; Dodge, J. S.; Broun, D. M.

2017-07-01

We calculate superfluid density for a dirty d -wave superconductor. The effects of impurity scattering are treated within the self-consistent t -matrix approximation, in weak-coupling BCS theory. Working from a realistic tight-binding parametrization of the Fermi surface, we find a superfluid density that is both correlated with Tc and linear in temperature, in good correspondence with recent experiments on overdoped La2 -xSrxCuO4 .

(d ,n ) proton-transfer reactions on 9Be, 11B, 13C, N,1514, and 19F and spectroscopic factors at Ed=16 MeV

NASA Astrophysics Data System (ADS)

Febbraro, M.; Becchetti, F. D.; Torres-Isea, R. O.; Riggins, J.; Lawrence, C. C.; Kolata, J. J.; Howard, A. M.

2017-08-01

The (d ,n ) reaction has been studied with targets of 9Be, 11B, 13C, N,1514, and 19F at Ed=16 MeV using a deuterated liquid-scintillator array. Advanced spectral unfolding techniques with accurately measured scintillator response functions were employed to extract neutron energy spectra without the need for long-path neutron time-of-flight. An analysis of the proton-transfer data at forward angles to the ground states of the final nuclei, using finite-range distorted-wave Born approximation analysis with common bound-state, global, and local optical-model parameter sets, yields a set of self-consistent spectroscopic factors. These are compared with the results of several previous time-of-flight measurements, most done many years ago for individual nuclei at lower energy and often analyzed using zero-range transfer codes. In contrast to some of the earlier published data, our data generally compare well with simple shell-model predictions, with little evidence for uniform quenching (reduction from shell-model values) that has previously been reported from analysis of nucleon knock-out reactions. Data for low-lying excited states in 14N from 13C(d ,n ) also is analyzed and spectroscopic information relevant to nuclear astrophysics obtained. A preliminary study of the radioactive ion beam induced reaction 7Be(d ,n ) , E (7Be)=30 MeV was carried out and indicates further improvements are needed for such measurements, which require detection of neutrons with En<2 MeV .

LONG-DURATION X-RAY FLASH AND X-RAY-RICH GAMMA-RAY BURSTS FROM LOW-MASS POPULATION III STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakauchi, Daisuke; Kashiyama, Kazumi; Nakamura, Takashi

2012-11-10

Recent numerical simulations suggest that Population III (Pop III) stars were born with masses not larger than {approx}100 M {sub Sun} and typically {approx}40 M {sub Sun }. By self-consistently considering the jet generation and propagation in the envelope of these low-mass Pop III stars, we find that a Pop III blue supergiant star has the possibility of giving rise to a gamma-ray burst (GRB) even though it keeps a massive hydrogen envelope. We evaluate observational characteristics of Pop III GRBs and predict that Pop III GRBs have a duration of {approx}10{sup 5} s in the observer frame and amore » peak luminosity of {approx}5 Multiplication-Sign 10{sup 50} erg s{sup -1}. Assuming that the E {sub p}-L {sub p} (or E {sub p}-E {sub {gamma},iso}) correlation holds for Pop III GRBs, we find that the spectrum peak energy falls at approximately a few keV (or {approx}100 keV) in the observer frame. We discuss the detectability of Pop III GRBs by future satellite missions such as EXIST and Lobster. If the E {sub p}-E {sub {gamma},iso} correlation holds, we have the possibility to detect Pop III GRBs at z {approx} 9 as long-duration X-ray-rich GRBs by EXIST. Conversely, if the E {sub p}-L {sub p} correlation holds, we have the possibility to detect Pop III GRBs up to z {approx} 19 as long-duration X-ray flashes by Lobster.« less

Phase-field simulation of microstructure formation in technical castings - A self-consistent homoenthalpic approach to the micro-macro problem

NASA Astrophysics Data System (ADS)

Böttger, B.; Eiken, J.; Apel, M.

2009-10-01

Performing microstructure simulation of technical casting processes suffers from the strong interdependency between latent heat release due to local microstructure formation and heat diffusion on the macroscopic scale: local microstructure formation depends on the macroscopic heat fluxes and, in turn, the macroscopic temperature solution depends on the latent heat release, and therefore on the microstructure formation, in all parts of the casting. A self-consistent homoenthalpic approximation to this micro-macro problem is proposed, based on the assumption of a common enthalpy-temperature relation for the whole casting which is used for the description of latent heat production on the macroscale. This enthalpy-temperature relation is iteratively obtained by phase-field simulations on the microscale, thus taking into account the specific morphological impact on the latent heat production. This new approach is discussed and compared to other approximations for the coupling of the macroscopic heat flux to complex microstructure models. Simulations are performed for the binary alloy Al-3at%Cu, using a multiphase-field solidification model which is coupled to a thermodynamic database. Microstructure formation is simulated for several positions in a simple model plate casting, using a one-dimensional macroscopic temperature solver which can be directly coupled to the microscopic phase-field simulation tool.

Extension of the self-consistent-charge density-functional tight-binding method: third-order expansion of the density functional theory total energy and introduction of a modified effective coulomb interaction.

PubMed

Yang, Yang; Yu, Haibo; York, Darrin; Cui, Qiang; Elstner, Marcus

2007-10-25

The standard self-consistent-charge density-functional-tight-binding (SCC-DFTB) method (Phys. Rev. B 1998, 58, 7260) is derived by a second-order expansion of the density functional theory total energy expression, followed by an approximation of the charge density fluctuations by charge monopoles and an effective damped Coulomb interaction between the atomic net charges. The central assumptions behind this effective charge-charge interaction are the inverse relation of atomic size and chemical hardness and the use of a fixed chemical hardness parameter independent of the atomic charge state. While these approximations seem to be unproblematic for many covalently bound systems, they are quantitatively insufficient for hydrogen-bonding interactions and (anionic) molecules with localized net charges. Here, we present an extension of the SCC-DFTB method to incorporate third-order terms in the charge density fluctuations, leading to chemical hardness parameters that are dependent on the atomic charge state and a modification of the Coulomb scaling to improve the electrostatic treatment within the second-order terms. These modifications lead to a significant improvement in the description of hydrogen-bonding interactions and proton affinities of biologically relevant molecules.

Semiclassical theory of the self-consistent vibration-rotation fields and its application to the bending-rotation interaction in the H{sub 2}O molecule

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skalozub, A.S.; Tsaune, A.Ya.

1994-12-01

A new approach for analyzing the highly excited vibration-rotation (VR) states of nonrigid molecules is suggested. It is based on the separation of the vibrational and rotational terms in the molecular VR Hamiltonian by introducing periodic auxiliary fields. These fields transfer different interactions within a molecule and are treated in terms of the mean-field approximation. As a result, the solution of the stationary Schroedinger equation with the VR Hamiltonian amounts to a quantization of the Berry phase in a problem of the molecular angular-momentum motion in a certain periodic VR field (rotational problem). The quantization procedure takes into account themore » motion of the collective vibrational variables in the appropriate VR potentials (vibrational problem). The quantization rules, the mean-field configurations of auxiliary interactions, and the solutions to the Schrodinger equations for the vibrational and rotational problems are self-consistently connected with one another. The potentialities of the theory are demonstrated by the bending-rotation interaction modeled by the Bunker-Landsberg potential function in the H{sub 2} molecule. The calculations are compared with both the results of the exact computations and those of other approximate methods. 32 refs., 4 tabs.« less

Simulating the spread of malaria using a generic transmission model for mosquito-borne infectious diseases

NASA Astrophysics Data System (ADS)

Kon, Cynthia Mui Lian; Labadin, Jane

2016-06-01

Malaria is a critical infection caused by parasites which are spread to humans through mosquito bites. Approximately half of the world's population is in peril of getting infected by malaria. Mosquito-borne diseases have a standard behavior where they are transmitted in the same manner, only through vector mosquito. Taking this into account, a generic spatial-temporal model for transmission of multiple mosquito-borne diseases had been formulated. Our interest is to reproduce the actual cases of different mosquito-borne diseases using the generic model and then predict future cases so as to improve control and target measures competently. In this paper, we utilize notified weekly malaria cases in four districts in Sarawak, Malaysia, namely Kapit, Song, Belaga and Marudi. The actual cases for 36 weeks, which is from week 39 in 2012 to week 22 in 2013, are compared with simulations of the generic spatial-temporal transmission mosquito-borne diseases model. We observe that the simulation results display corresponding result to the actual malaria cases in the four districts.

Multigrid based First-Principles Molecular Dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fattebert, Jean-Luc; Osei-Kuffuor, Daniel; Dunn, Ian

2017-06-01

MGmol ls a First-Principles Molecular Dynamics code. It relies on the Born-Oppenheimer approximation and models the electronic structure using Density Functional Theory, either LDA or PBE. Norm-conserving pseudopotentials are used to model atomic cores.

The Primordial Inflation Polarization Explorer (PIPER)

NASA Technical Reports Server (NTRS)

Chuss, David T.

2008-01-01

The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne experiment designed to search for the polarized imprint of gravitational waves from cosmic inflation. The discovery of such a signal would provide direct evidence for inflation, and its characterization would provide a means to explore energy scales orders of magnitude larger than any conceivable particle accelerator. PIPER will consist of two cryogenic telescopes-one for each of the Q and U Stokes parameters. Each will use a variable-delay polarization modulator (VPM) as its first element. This architecture is designed to minimize both T->B and E->B systematics. The detectors will be four 32x40 arrays of BUG detectors, utilizing transition-edge sensors and time-domain multiplexing. Each flight will observe approximately 25% of the sky at a single frequency. Additional flights will increase the frequency coverage.

Modeling of SAR returns from a red pine stand

NASA Technical Reports Server (NTRS)

Lang, R. H.; Kilic, O.; Chauhan, N. S.; Ranson, J.

1992-01-01

Bright P-band radar returns from red pine forests have been observed on synthetic aperture radar (SAR) images in Bangor, Maine. A plot of red pine trees was selected for the characterization and modeling to understand the cause of the high P-band returns. The red pine stand under study consisted of mature trees. Diameter at breast height (DBH) measurements were made to determine stand density as a function of tree diameter. Soil moisture and bulk density measurements were taken along with ground rough surface profiles. Detailed biomass measurements of the needles, shoots, branches, and trunks were also taken. These site statistics have been used in a distorted Born approximation model of the forest. Computations indicate that the direct-reflected or the double-bounce contributions from the ground are responsible for the high observed P-band returns for HH polarization.

Berry phase and Hannay's angle in a quantum-classical hybrid system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, H. D.; Wu, S. L.; Yi, X. X.

2011-06-15

The Berry phase, which was discovered more than two decades ago, provides very deep insight into the geometric structure of quantum mechanics. Its classical counterpart, Hannay's angle, is defined if closed curves of action variables return to the same curves in phase space after a time evolution. In this paper we study the Berry phase and Hannay's angle in a quantum-classical hybrid system under the Born-Oppenheimer approximation. By the term quantum-classical hybrid system, we mean a composite system consists of a quantum subsystem and a classical subsystem. The effects of subsystem-subsystem couplings on the Berry phase and Hannay's angle aremore » explored. The results show that the Berry phase has been changed sharply by the couplings, whereas the couplings have a small effect on the Hannay's angle.« less

Accelerating medical innovation at USC: realizing the dream of Alfred E. Mann.

PubMed

Gosset, Nathalie; Lasch, Jonathan G

2012-07-01

Alfred E. Mann's vision is to create organizations that will help medical innovations born in academic environments evolve into commercially fit solutions, without the risk of being abandoned under the financial pressures early stage start-ups often experience. In 1998, Mann worked with Stephen Sample, president of USC, to create the first AMI for Biomedical Engineering, an organization fueled by an endowment valued at approximately US$160 million today. Technology-acceleration centers come in different flavors. AMI USC's recipe has evolved since its creation, with edits that incorporate lessons learned and improvements brought by its expanding network of talented resource people. Its 15-member staff, consisting of three-fourths industry professionals, includes seasoned generalists and specialists in medical technology commercialization. Although the support varies with each invention, some recurring ingredients weave into the AMI approach to accelerating medical innovation.

Inner Core Anisotropy: Can Seismic Observations be Reconciled with Ab Initio Calculations of Elasticity?

NASA Astrophysics Data System (ADS)

Song, X.; Jordan, T. H.

2016-12-01

Body-wave and normal-mode observations have revealed an inner-core structure that is radially layered, axially anisotropic, and hemispherically asymmetric. Previous theoretical studies have examined the consistency of these features with the elasticity of iron crystals thought to dominate inner-core composition, but a fully consistent model has been elusive. Here we compare the seismic observation with effective-medium models derived from ab initio calculations of the elasticity tensors for hcp-Fe and bcc-Fe. Our estimates are based on Jordan's (GJI, 2015) effective medium theory, which is derived from a self-consistent, second-order Born approximation. The theory provides closed-form expressions for the effective elastic parameters of 3D anisotropic, heterogeneous media in which the local anisotropy is a constant hexagonal stiffness tensor C stochastically oriented about a constant symmetry axis \\hat{s} and the statistics of the small-scale heterogeneities are transversely isotropic in the plane perpendicular to \\hat{s}. The stochastic model is then described by a dimensionless "aspect ratio of the heterogeneity", 0 ≤ η < ∞, and a dimensionless "orientation ratio of the anisotropy", 0 ≤ ξ < ∞. The latter determines the degree to which the axis of C is aligned with \\hat{s}. We compute the loci of models with \\hat{s} oriented along the Earth's rotational axis ( \\hat{s} = north) by varying ξ and η for various ab initio estimates of C. We show that a lot of widely used estimates of C are inconsistent with most published normal-mode models of inner-core anisotropy. In particular, if the P-wave fast axis aligns with the rotational axis, which is required to satisfy the body-wave observations, then these hcp-Fe models predict that the fast polarization of the S waves is in the plane perpendicular to \\hat{s}, which disagrees with most normal-mode models. We have attempted to resolve this discrepancy by examining alternative hcp-Fe models, including radially anisotropic distributions of stochastic anisotropy and heterogeneity (i.e., where \\hat{s} = \\hat{r}), as well as bcc-Fe models. Our calculations constrain the form of C needed to satisfy the seismological inferences.

From Never Born Proteins to Minimal Living Cells: two projects in synthetic biology.

PubMed

Luisi, Pier Luigi; Chiarabelli, Cristiano; Stano, Pasquale

2006-12-01

The Never Born Proteins (NBPs) and the Minimal Cell projects are two currently developed research lines belonging to the field of synthetic biology. The first deals with the investigation of structural and functional properties of de novo proteins with random sequences, selected and isolated using phage display methods. The minimal cell is the simplest cellular construct which displays living properties, such as self-maintenance, self-reproduction and evolvability. The semi-synthetic approach to minimal cells involves the use of extant genes and proteins in order to build a supramolecular construct based on lipid vesicles. Results and outlooks on these two research lines are shortly discussed, mainly focusing on their relevance to the origin of life studies.

The relative importance of prey-borne and predator-borne chemical cues for inducible antipredator responses in tadpoles.

PubMed

Hettyey, Attila; Tóth, Zoltán; Thonhauser, Kerstin E; Frommen, Joachim G; Penn, Dustin J; Van Buskirk, Josh

2015-11-01

Chemical cues that evoke anti-predator developmental changes have received considerable attention, but it is not known to what extent prey use information from the smell of predators and from cues released through digestion. We conducted an experiment to determine the importance of various types of cues for the adjustment of anti-predator defences. We exposed tadpoles (common frog, Rana temporaria) to water originating from predators (caged dragonfly larvae, Aeshna cyanea) that were fed different types and quantities of prey outside of tadpole-rearing containers. Variation among treatments in the magnitude of morphological and behavioural responses was highly consistent. Our results demonstrate that tadpoles can assess the threat posed by predators through digestion-released, prey-borne cues and continually released predator-borne cues. These cues may play an important role in the fine-tuning of anti-predator responses and significantly affect the outcome of interactions between predators and prey in aquatic ecosystems. There has been much confusion regards terminology used in the literature, and therefore we also propose a more precise and consistent binomial nomenclature based on the timing of chemical cue release (stress-, attack-, capture-, digestion- or continually released cues) and the origin of cues (prey-borne or predator-borne cues). We hope that this new nomenclature will improve comparisons among studies on this topic.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parrish, Robert M.; Liu, Fang; Martínez, Todd J., E-mail: toddjmartinez@gmail.com

We formulate self-consistent field (SCF) theory in terms of an interaction picture where the working variable is the difference density matrix between the true system and a corresponding superposition of atomic densities. As the difference density matrix directly represents the electronic deformations inherent in chemical bonding, this “difference self-consistent field (dSCF)” picture provides a number of significant conceptual and computational advantages. We show that this allows for a stable and efficient dSCF iterative procedure with wholly single-precision Coulomb and exchange matrix builds. We also show that the dSCF iterative procedure can be performed with aggressive screening of the pair space.more » These approximations are tested and found to be accurate for systems with up to 1860 atoms and >10 000 basis functions, providing for immediate overall speedups of up to 70% in the heavily optimized TERACHEM SCF implementation.« less