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.

How large are nonadiabatic effects in atomic and diatomic systems?

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

Yang, Yubo, E-mail: yyang173@illinois.edu, E-mail: normantubman2015@u.northwestern.edu; Tubman, Norm M., E-mail: yyang173@illinois.edu, E-mail: normantubman2015@u.northwestern.edu; Ceperley, David M.

2015-09-28

With recent developments in simulating nonadiabatic systems to high accuracy, it has become possible to determine how much energy is attributed to nuclear quantum effects beyond zero-point energy. In this work, we calculate the non-relativistic ground-state energies of atomic and molecular systems without the Born-Oppenheimer approximation. For this purpose, we utilize the fixed-node diffusion Monte Carlo method, in which the nodes depend on both the electronic and ionic positions. We report ground-state energies for all systems studied, ionization energies for the first-row atoms and atomization energies for the first-row hydrides. We find the ionization energies of the atoms to bemore » nearly independent of the Born-Oppenheimer approximation, within the accuracy of our results. The atomization energies of molecular systems, however, show small effects of the nonadiabatic coupling between electrons and nuclei.« less

How large are nonadiabatic effects in atomic and diatomic systems?

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

Yang, Yubo; Kylänpää, Ilkka; Tubman, Norm M.

2015-09-29

With recent developments in simulating nonadiabatic systems to high accuracy, it has become possible to determine how much energy is attributed to nuclear quantum effects beyond zero-point energy. Here, we calculate the non-relativistic ground-state energies of atomic and molecular systems without the Born-Oppenheimer approximation. For this purpose, we utilize the fixed-node diffusion Monte Carlo method, in which the nodes depend on both the electronic and ionic positions. Our report shows the ground-state energies for all systems studied, ionization energies for the first-row atoms and atomization energies for the first-row hydrides. We find the ionization energies of the atoms to bemore » nearly independent of the Born-Oppenheimer approximation, within the accuracy of our results. The atomization energies of molecular systems, however, show small effects of the nonadiabatic coupling between electrons and nuclei.« less

Validity of the Born approximation for beyond Gaussian weak lensing observables

DOE PAGES

Petri, Andrea; Haiman, Zoltan; May, Morgan

2017-06-06

Accurate forward modeling of weak lensing (WL) observables from cosmological parameters is necessary for upcoming galaxy surveys. Because WL probes structures in the nonlinear regime, analytical forward modeling is very challenging, if not impossible. Numerical simulations of WL features rely on ray tracing through the outputs of N-body simulations, which requires knowledge of the gravitational potential and accurate solvers for light ray trajectories. A less accurate procedure, based on the Born approximation, only requires knowledge of the density field, and can be implemented more efficiently and at a lower computational cost. In this work, we use simulations to show thatmore » deviations of the Born-approximated convergence power spectrum, skewness and kurtosis from their fully ray-traced counterparts are consistent with the smallest nontrivial O(Φ 3) post-Born corrections (so-called geodesic and lens-lens terms). Our results imply a cancellation among the larger O(Φ 4) (and higher order) terms, consistent with previous analytic work. We also find that cosmological parameter bias induced by the Born-approximated power spectrum is negligible even for a LSST-like survey, once galaxy shape noise is considered. When considering higher order statistics such as the κ skewness and kurtosis, however, we find significant bias of up to 2.5σ. Using the LensTools software suite, we show that the Born approximation saves a factor of 4 in computing time with respect to the full ray tracing in reconstructing the convergence.« less

Validity of the Born approximation for beyond Gaussian weak lensing observables

NASA Astrophysics Data System (ADS)

Petri, Andrea; Haiman, Zoltán; May, Morgan

2017-06-01

Accurate forward modeling of weak lensing (WL) observables from cosmological parameters is necessary for upcoming galaxy surveys. Because WL probes structures in the nonlinear regime, analytical forward modeling is very challenging, if not impossible. Numerical simulations of WL features rely on ray tracing through the outputs of N -body simulations, which requires knowledge of the gravitational potential and accurate solvers for light ray trajectories. A less accurate procedure, based on the Born approximation, only requires knowledge of the density field, and can be implemented more efficiently and at a lower computational cost. In this work, we use simulations to show that deviations of the Born-approximated convergence power spectrum, skewness and kurtosis from their fully ray-traced counterparts are consistent with the smallest nontrivial O (Φ3) post-Born corrections (so-called geodesic and lens-lens terms). Our results imply a cancellation among the larger O (Φ4) (and higher order) terms, consistent with previous analytic work. We also find that cosmological parameter bias induced by the Born-approximated power spectrum is negligible even for a LSST-like survey, once galaxy shape noise is considered. When considering higher order statistics such as the κ skewness and kurtosis, however, we find significant bias of up to 2.5 σ . Using the LensTools software suite, we show that the Born approximation saves a factor of 4 in computing time with respect to the full ray tracing in reconstructing the convergence.

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.

Variationally consistent approximation scheme for charge transfer

NASA Technical Reports Server (NTRS)

Halpern, A. M.

1978-01-01

The author has developed a technique for testing various charge-transfer approximation schemes for consistency with the requirements of the Kohn variational principle for the amplitude to guarantee that the amplitude is correct to second order in the scattering wave functions. Applied to Born-type approximations for charge transfer it allows the selection of particular groups of first-, second-, and higher-Born-type terms that obey the consistency requirement, and hence yield more reliable approximation to the amplitude.

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

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.

Born-Oppenheimer approximation in an effective field theory language

NASA Astrophysics Data System (ADS)

Brambilla, Nora; Krein, Gastão; Tarrús Castellà, Jaume; Vairo, Antonio

2018-01-01

The Born-Oppenheimer approximation is the standard tool for the study of molecular systems. It is founded on the observation that the energy scale of the electron dynamics in a molecule is larger than that of the nuclei. A very similar physical picture can be used to describe QCD states containing heavy quarks as well as light-quarks or gluonic excitations. In this work, we derive the Born-Oppenheimer approximation for QED molecular systems in an effective field theory framework by sequentially integrating out degrees of freedom living at energies above the typical energy scale where the dynamics of the heavy degrees of freedom occurs. In particular, we compute the matching coefficients of the effective field theory for the case of the H2+ diatomic molecule that are relevant to compute its spectrum up to O (m α5). Ultrasoft photon loops contribute at this order, being ultimately responsible for the molecular Lamb shift. In the effective field theory the scaling of all the operators is homogeneous, which facilitates the determination of all the relevant contributions, an observation that may become useful for high-precision calculations. Using the above case as a guidance, we construct under some conditions an effective field theory for QCD states formed by a color-octet heavy quark-antiquark pair bound with a color-octet light-quark pair or excited gluonic state, highlighting the similarities and differences between the QED and QCD systems. Assuming that the multipole expansion is applicable, we construct the heavy-quark potential up to next-to-leading order in the multipole expansion in terms of nonperturbative matching coefficients to be obtained from lattice QCD.

Many-body Green’s function theory for electron-phonon interactions: Ground state properties of the Holstein dimer

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

Säkkinen, Niko; Leeuwen, Robert van; Peng, Yang

2015-12-21

We study ground-state properties of a two-site, two-electron Holstein model describing two molecules coupled indirectly via electron-phonon interaction by using both exact diagonalization and self-consistent diagrammatic many-body perturbation theory. The Hartree and self-consistent Born approximations used in the present work are studied at different levels of self-consistency. The governing equations are shown to exhibit multiple solutions when the electron-phonon interaction is sufficiently strong, whereas at smaller interactions, only a single solution is found. The additional solutions at larger electron-phonon couplings correspond to symmetry-broken states with inhomogeneous electron densities. A comparison to exact results indicates that this symmetry breaking is stronglymore » correlated with the formation of a bipolaron state in which the two electrons prefer to reside on the same molecule. The results further show that the Hartree and partially self-consistent Born solutions obtained by enforcing symmetry do not compare well with exact energetics, while the fully self-consistent Born approximation improves the qualitative and quantitative agreement with exact results in the same symmetric case. This together with a presented natural occupation number analysis supports the conclusion that the fully self-consistent approximation describes partially the bipolaron crossover. These results contribute to better understanding how these approximations cope with the strong localizing effect of the electron-phonon interaction.« less

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.

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

Environmental effects on long term behavior of composite laminates

NASA Astrophysics Data System (ADS)

Singhal, S. N.; Chamis, C. C.

Model equations are presented for approximate methods simulating the long-term behavior of composite materials and structures in hot/humid service environments. These equations allow laminate property upgradings with time, and can account for the effects of service environments on creep response. These methodologies are illustrated for various individual and coupled temperature/moisture, longitudinal/transverse, and composite material type cases. Creep deformation is noted to rise dramatically for cases of matrix-borne, but not of fiber-borne, loading in hot, humid environments; the coupled influence of temperature and moisture is greater than a mere combination of their individual influences.

Environmental effects on long term behavior of composite laminates

NASA Technical Reports Server (NTRS)

Singhal, S. N.; Chamis, C. C.

1992-01-01

Model equations are presented for approximate methods simulating the long-term behavior of composite materials and structures in hot/humid service environments. These equations allow laminate property upgradings with time, and can account for the effects of service environments on creep response. These methodologies are illustrated for various individual and coupled temperature/moisture, longitudinal/transverse, and composite material type cases. Creep deformation is noted to rise dramatically for cases of matrix-borne, but not of fiber-borne, loading in hot, humid environments; the coupled influence of temperature and moisture is greater than a mere combination of their individual influences.

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.

Inelastic cross sections for low-energy electrons in liquid water: exchange and correlation effects.

PubMed

Emfietzoglou, Dimitris; Kyriakou, Ioanna; Garcia-Molina, Rafael; Abril, Isabel; Nikjoo, Hooshang

2013-11-01

Low-energy electrons play a prominent role in radiation therapy and biology as they are the largest contributor to the absorbed dose. However, no tractable theory exists to describe the interaction of low-energy electrons with condensed media. This article presents a new approach to include exchange and correlation (XC) effects in inelastic electron scattering at low energies (below ∼10 keV) in the context of the dielectric theory. Specifically, an optical-data model of the dielectric response function of liquid water is developed that goes beyond the random phase approximation (RPA) by accounting for XC effects using the concept of the many-body local-field correction (LFC). It is shown that the experimental energy-loss-function of liquid water can be reproduced by including into the RPA dispersion relations XC effects (up to second order) calculated in the time-dependent local-density approximation with the addition of phonon-induced broadening in N. D. Mermin's relaxation-time approximation. Additional XC effects related to the incident and/or struck electrons are included by means of the vertex correction calculated by a modified Hubbard formula for the exchange-only LFC. Within the first Born approximation, the present XC corrections cause a significantly larger reduction (∼10-50%) to the inelastic cross section compared to the commonly used Mott and Ochkur approximations, while also yielding much better agreement with the recent experimental data for amorphous ice. The current work offers a manageable, yet rigorous, approach for including non-Born effects in the calculation of inelastic cross sections for low-energy electrons in liquid water, which due to its generality, can be easily extended to other condensed media.

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.

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.

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

Density functional theory of electron transfer beyond the Born-Oppenheimer approximation: Case study of LiF.

PubMed

Li, Chen; Requist, Ryan; Gross, E K U

2018-02-28

We perform model calculations for a stretched LiF molecule, demonstrating that nonadiabatic charge transfer effects can be accurately and seamlessly described within a density functional framework. In alkali halides like LiF, there is an abrupt change in the ground state electronic distribution due to an electron transfer at a critical bond length R = R c , where an avoided crossing of the lowest adiabatic potential energy surfaces calls the validity of the Born-Oppenheimer approximation into doubt. Modeling the R-dependent electronic structure of LiF within a two-site Hubbard model, we find that nonadiabatic electron-nuclear coupling produces a sizable elongation of the critical R c by 0.5 bohr. This effect is very accurately captured by a simple and rigorously derived correction, with an M -1 prefactor, to the exchange-correlation potential in density functional theory, M = reduced nuclear mass. Since this nonadiabatic term depends on gradients of the nuclear wave function and conditional electronic density, ∇ R χ(R) and ∇ R n(r, R), it couples the Kohn-Sham equations at neighboring R points. Motivated by an observed localization of nonadiabatic effects in nuclear configuration space, we propose a local conditional density approximation-an approximation that reduces the search for nonadiabatic density functionals to the search for a single function y(n).

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.

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.

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.

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.

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

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.

Density functional theory of electron transfer beyond the Born-Oppenheimer approximation: Case study of LiF

NASA Astrophysics Data System (ADS)

Li, Chen; Requist, Ryan; Gross, E. K. U.

2018-02-01

We perform model calculations for a stretched LiF molecule, demonstrating that nonadiabatic charge transfer effects can be accurately and seamlessly described within a density functional framework. In alkali halides like LiF, there is an abrupt change in the ground state electronic distribution due to an electron transfer at a critical bond length R = Rc, where an avoided crossing of the lowest adiabatic potential energy surfaces calls the validity of the Born-Oppenheimer approximation into doubt. Modeling the R-dependent electronic structure of LiF within a two-site Hubbard model, we find that nonadiabatic electron-nuclear coupling produces a sizable elongation of the critical Rc by 0.5 bohr. This effect is very accurately captured by a simple and rigorously derived correction, with an M-1 prefactor, to the exchange-correlation potential in density functional theory, M = reduced nuclear mass. Since this nonadiabatic term depends on gradients of the nuclear wave function and conditional electronic density, ∇Rχ(R) and ∇Rn(r, R), it couples the Kohn-Sham equations at neighboring R points. Motivated by an observed localization of nonadiabatic effects in nuclear configuration space, we propose a local conditional density approximation—an approximation that reduces the search for nonadiabatic density functionals to the search for a single function y(n).

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.

Aharonov-Casher effect and quantum transport in graphene based nano rings: A self-consistent Born approximation

NASA Astrophysics Data System (ADS)

Ghaderzadeh, A.; Rahbari, S. H. Ebrahimnazhad; Phirouznia, A.

2018-03-01

In this study, Rashba coupling induced Aharonov-Casher effect in a graphene based nano ring is investigated theoretically. The graphene based nano ring is considered as a central device connected to semi-infinite graphene nano ribbons. In the presence of the Rashba spin-orbit interaction, two armchair shaped edge nano ribbons are considered as semi-infinite leads. The non-equilibrium Green's function approach is utilized to obtain the quantum transport characteristics of the system. The relaxation and dephasing mechanisms within the self-consistent Born approximation is scrutinized. The Lopez-Sancho method is also applied to obtain the self-energy of the leads. We unveil that the non-equilibrium current of the system possesses measurable Aharonov-Casher oscillations with respect to the Rashba coupling strength. In addition, we have observed the same oscillations in dilute impurity regimes in which amplitude of the oscillations is shown to be suppressed as a result of the relaxations.

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.

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.

Direct pair production in heavy-ion--atom collisions

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

Anholt, R.; Jakubassa-Amundsen, D.H.; Amundsen, P.A.

1983-02-01

Direct pair production in approx.5-MeV/amu heavy-ion--atom collisions with uranium target atoms is calculated with the plane-wave Born approximation and the semiclassical approximation. Briggs's approximation is used to obtain the electron and positron wave functions. Since pair production involves high momentum transfer q from the moving projectile to the vacuum, use is made of a high-q approximation to greatly simplify the numerical computations. Coulomb deflection of the projectile, the effect of finite nuclear size on the elec- tronic wave functions, and the energy loss by the projectile exciting the pair are all taken into account in these calculations.

Force-field functor theory: classical force-fields which reproduce equilibrium quantum distributions

PubMed Central

Babbush, Ryan; Parkhill, John; Aspuru-Guzik, Alán

2013-01-01

Feynman and Hibbs were the first to variationally determine an effective potential whose associated classical canonical ensemble approximates the exact quantum partition function. We examine the existence of a map between the local potential and an effective classical potential which matches the exact quantum equilibrium density and partition function. The usefulness of such a mapping rests in its ability to readily improve Born-Oppenheimer potentials for use with classical sampling. We show that such a map is unique and must exist. To explore the feasibility of using this result to improve classical molecular mechanics, we numerically produce a map from a library of randomly generated one-dimensional potential/effective potential pairs then evaluate its performance on independent test problems. We also apply the map to simulate liquid para-hydrogen, finding that the resulting radial pair distribution functions agree well with path integral Monte Carlo simulations. The surprising accessibility and transferability of the technique suggest a quantitative route to adapting Born-Oppenheimer potentials, with a motivation similar in spirit to the powerful ideas and approximations of density functional theory. PMID:24790954

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.

Ionization potential depression and optical spectra in a Debye plasma model

NASA Astrophysics Data System (ADS)

Lin, Chengliang; Röpke, Gerd; Reinholz, Heidi; Kraeft, Wolf-Dietrich

2017-11-01

We show how optical spectra in dense plasmas are determined by the shift of energy levels as well as the broadening owing to collisions with the plasma particles. In lowest approximation, the interaction with the plasma particles is described by the RPA dielectric function, leading to the Debye shift of the continuum edge. The bound states remain nearly un-shifted, their broadening is calculated in Born approximation. The role of ionization potential depression as well as the Inglis-Teller effect are shown. The model calculations have to be improved going beyond the lowest (RPA) approximation when applying to WDM spectra.

THE NATIONAL CHILDREN'S STUDY: BEGINNING THE IMPLEMENTATION OF A NATIONAL-PROBABILITY SAMPLE

EPA Science Inventory

Introduction: The National Children's Study (NCS) is a longitudinal cohort study that will follow a sample of approximately 100,000 children born in the United States from before birth until 21 years of age. The NCS will investigate the separate and combined effects of environmen...

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.

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…

Scattering of electromagnetic waves from a half-space of randomly distributed discrete scatterers and polarized backscattering ratio law

NASA Technical Reports Server (NTRS)

Zhu, P. Y.

1991-01-01

The effective-medium approximation is applied to investigate scattering from a half-space of randomly and densely distributed discrete scatterers. Starting from vector wave equations, an approximation, called effective-medium Born approximation, a particular way, treating Green's functions, and special coordinates, of which the origin is set at the field point, are used to calculate the bistatic- and back-scatterings. An analytic solution of backscattering with closed form is obtained and it shows a depolarization effect. The theoretical results are in good agreement with the experimental measurements in the cases of snow, multi- and first-year sea-ice. The root product ratio of polarization to depolarization in backscattering is equal to 8; this result constitutes a law about polarized scattering phenomena in the nature.

Interpretation of ES, CS, and IOS approximations within a translational-internal coupling scheme. II. Application to atom--diatom kinetic cross sections

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

Coombe, D.A.; Snider, R.F.

1980-02-15

ES, CS, and IOS approximations to atom--diatom kinetic cross sections are derived. In doing so, reduced S-matrices in a translational-internal coupling scheme are stressed. This entails the insertion of recently obtained approximate reduced S-matrices in the translational-internal coupling scheme into previously derived general expressions for the kinetic cross sections. Of special interest is the structure (rotational j quantum number dependence) of the kinetic cross sections associated with the Senftleben Beenakker effects and of pure internal state relaxation phenomena. The viscomagnetic effect is used as an illustrative example. It is found in particular that there is a great similarity of structuremore » between the energy sudden (and IOS) approximation and the previously derived distorted wave Born results.« 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.

The Generalized Born solvation model: What is it?

NASA Astrophysics Data System (ADS)

Onufriev, Alexey

2004-03-01

Implicit solvation models provide, for many applications, an effective way of describing the electrostatic effects of aqueous solvation. Here we outline the main approximations behind the popular Generalized Born solvation model. We show how its accuracy, relative to the Poisson-Boltzmann treatment, can be significantly improved in a computationally inexpensive manner to make the model useful in the studies of large-scale conformational transitions at the atomic level. The improved model is tested in a molecular dynamics simulation of folding of a 46-residue (three helix bundle) protein. Starting from an extended structure at 450K, the protein folds to the lowest energy conformation within 6 ns of simulation time, and the predicted structure differs from the native one by 2.4 A (backbone RMSD).

Multiple outer-shell ionization effect in inner-shell x-ray production by light ions

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

Lapicki, G.; Mehta, R.; Duggan, J.L.

1986-11-01

L-shell x-ray production cross sections by 0.25--2.5-MeV /sub 2//sup 4/He/sup +/ ions in /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 are reported. The data are compared to the first Born approximation and the ECPSSR theory that accounts for the projectile energy loss (E) and Coulomb deflection (C) as well as the perturbed-stationary-state (PSS) and relativistic (R) effects in the treatment of the target L-shell electron. Surprisingly, the first Born approximation appears to converge to the data while the ECPSSR predictions underestimate them in the low-velocity limit. This ismore » explained as the result of improper use of single-hole fluorescence yields. A heuristic formula is proposed to account for multiple ionizations in terms of a classical probability for these phenomena and, after it is applied, the ECPSSR theory of L-shell ionization is found to be in good agreement with the data.« less

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.

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 ...

The extreme ultraviolet spectrograph: A radial groove grating, sounding rocket-borne, astronomical instrument

NASA Technical Reports Server (NTRS)

Wilkinson, Erik; Green, James C.; Cash, Webster

1993-01-01

The design, calibration, and sounding rocket flight performance of a novel spectrograph suitable for moderate-resolution EUV spectroscopy are presented. The sounding rocket-borne instrument uses a radial groove grating to maintain a high system efficiency while controlling the aberrations induced when doing spectroscopy in a converging beam. The instrument has a resolution of approximately 2 A across the 200-330 A bandpass with an average effective area of 2 sq cm. The instrument, called the Extreme Ultraviolet Spectrograph, acquired the first EUV spectra in this wavelength region of the hot white dwarf G191-B2B and the late-type star Capella.

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

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

PubMed

Almazan, Consuelo; Tipacamu, Gabriela Aguilar; Rodriguez, Sergio; Mosqueda, Juan; Perez de Leon, Adalberto

2018-03-01

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. The most economically important tick species parasitizing cattle in Mexico are Rhipicephalus microplus , R. annulatus , and Amblyomma mixtum . Parasitism by ticks affects cattle health and production directly. Morbidity and mortality caused by tick-borne diseases augment the detrimental effect of tick infestation in cattle. Bovine babesiosis and anaplasmosis are the most important tick-borne diseases of cattle, which are caused by infectious agents transmitted by R. microplus and R. annulatus . However, there are no prophylactic therapies to control bovine babesiosis and anaplasmosis. Chemical control is the most common way to treat animals against ticks, and the use of acaricides can also help manage tick-borne diseases. However, the evolution of resistance to acaricides among cattle tick populations renders chemical control ineffective; which represents a challenge for sustainable ticks and tick-borne diseases control. The only anti-tick vaccine commercially available globally is based on the recombinant antigen Bm86. Because of its mode of immunity against R. microplus and R. annulatus , the Bm86-based vaccine also decreases the exposition of bovines to babesiosis and anaplasmosis. Research with Bm86-based vaccines documented high efficacy against R. annulatus , the efficacy levels against R. microplus varies according to the geographic origin of tick populations, and there is not effect against other ticks species such as Amblyomma spp. The impact of ticks and tick-borne diseases, the problem of chemical control due to acaricide resistance, and progress with anti-tick vaccine research efforts in Mexico are reviewed herein.

Electron-impact ionization of Ne (2 p ) and Ar (3 p ) at intermediate energies: Role of the postcollision interaction

NASA Astrophysics Data System (ADS)

Hu, Xiaoqing; Gao, Cong-Zhang; Chen, Zhanbin; Wang, Jianguo; Wu, Yong; Wang, Yang

2017-11-01

We present the absolute triple differential cross section (TDCS) for single ionization of Ne (2 p ) at an impact energy of 599.6 eV and Ar (3 p ) at 195 eV. The role of the postcollision interaction (PCI) is studied using a high-order distorted-wave Born approximation model with a continuum distorted-waves expansion. Both the second- and third-order effects are considered in the present calculations, and the third-order distorted wave Born approximation model is reported in the (e ,2 e ) reaction. The calculated results show satisfactory agreement with experimental data. The magnitude of the absolute TDCS is enhanced by a factor 2-3 when the strength factor γ of the PCI amplitude is summarized just from 0 to 2. This proves that the PCI plays an important role in the absolute TDCS of the (e ,2 e ) reaction in the intermediate-energy region.

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.

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).

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.

The Effect of Childhood Family Size on Fertility in Adulthood: New Evidence From IV Estimation.

PubMed

Cools, Sara; Kaldager Hart, Rannveig

2017-02-01

Although fertility is positively correlated across generations, the causal effect of children's experience with larger sibships on their own fertility in adulthood is poorly understood. With the sex composition of the two firstborn children as an instrumental variable, we estimate the effect of sibship size on adult fertility using high-quality data from Norwegian administrative registers. Our study sample is all firstborns or second-borns during the 1960s in Norwegian families with at least two children (approximately 110,000 men and 104,000 women). An additional sibling has a positive effect on male fertility, mainly causing them to have three children themselves, but has a negative effect on female fertility at the same margin. Investigation into mediators reveals that mothers of girls shift relatively less time from market to family work when an additional child is born. We speculate that this scarcity in parents' time makes girls aware of the strains of life in large families, leading them to limit their own number of children in adulthood.

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.

On the Mass of Atoms in Molecules: Beyond the Born-Oppenheimer Approximation

NASA Astrophysics Data System (ADS)

Scherrer, Arne; Agostini, Federica; Sebastiani, Daniel; Gross, E. K. U.; Vuilleumier, Rodolphe

2017-07-01

Describing the dynamics of nuclei in molecules requires a potential energy surface, which is traditionally provided by the Born-Oppenheimer or adiabatic approximation. However, we also need to assign masses to the nuclei. There, the Born-Oppenheimer picture does not account for the inertia of the electrons, and only bare nuclear masses are considered. Nowadays, experimental accuracy challenges the theoretical predictions of rotational and vibrational spectra and requires the participation of electrons in the internal motion of the molecule. More than 80 years after the original work of Born and Oppenheimer, this issue has still not been solved, in general. Here, we present a theoretical and numerical framework to address this problem in a general and rigorous way. Starting from the exact factorization of the electron-nuclear wave function, we include electronic effects beyond the Born-Oppenheimer regime in a perturbative way via position-dependent corrections to the bare nuclear masses. This maintains an adiabaticlike point of view: The nuclear degrees of freedom feel the presence of the electrons via a single potential energy surface, whereas the inertia of electrons is accounted for and the total mass of the system is recovered. This constitutes a general framework for describing the mass acquired by slow degrees of freedom due to the inertia of light, bounded particles; thus, it is applicable not only in electron-nuclear systems but in light-heavy nuclei or ions as well. We illustrate this idea with a model of proton transfer, where the light particle is the proton and the heavy particles are the oxygen atoms to which the proton is bounded. Inclusion of the light-particle inertia allows us to gain orders of magnitude in accuracy. The electron-nuclear perspective is adopted, instead, to calculate position-dependent mass corrections using density functional theory for a few polyatomic molecules at their equilibrium geometry. These data can serve as input for the computation of high-precision molecular spectra.

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

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.

Effective Hamiltonian approach to the Kerr nonlinearity in an optomechanical system

NASA Astrophysics Data System (ADS)

Gong, Z. R.; Ian, H.; Liu, Yu-Xi; Sun, C. P.; Nori, Franco

2009-12-01

Using the Born-Oppenheimer approximation, we derive an effective Hamiltonian for an optomechanical system that leads to a nonlinear Kerr effect in the system’s vacuum. The oscillating mirror at one edge of the optomechanical system induces a squeezing effect in the intensity spectrum of the cavity field. A near-resonant laser field is applied at the other edge to drive the cavity field in order to enhance the Kerr effect. We also propose a quantum-nondemolition-measurement setup to monitor a system with two cavities separated by a common oscillating mirror based on our effective Hamiltonian approach.

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...

A balloon-borne instrument for high-resolution astrophysical spectroscopy in the 20-8000 keV energy range

NASA Technical Reports Server (NTRS)

Paciesas, W. S.; Baker, R.; Boclet, D.; Brown, S.; Cline, T.; Costlow, H.; Durouchoux, P.; Ehrmann, C.; Gehrels, N.; Hameury, J. M.

1983-01-01

The Low Energy Gamma ray Spectrometer (LEGS) is designed to perform fine energy resolution measurements of astrophysical sources. The instrument is configured for a particular balloon flight with either of two sets of high purity germanium detectors. In one configuration, the instrument uses an array of three coaxial detectors (effective volume equal to or approximately 230 cubic cm) inside an NaI (T1) shield and collimator (field of view equal to or approximately 16 deg FWHM) and operates in the 80 to 8000 keV energy range. In the other configuration, three planar detectors (effective area equal to or approximately square cm) surrounded by a combination of passive Fe and active NaI for shielding and collimation (field of view equal to or approximately 5 deg x 10 deg FWHM) are optimized for the 20 to 200 keV energy range. In a typical one day balloon flight, LEGS sensitivity limit (3 sigma) for narrow line features is less than or approximately .0008 ph/cm/s square (coaxial array: 80 to 2000 keV) and less than or approximately .0003 ph/square cm/s (planar array: 50 to 150 keV).

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.

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.

Nuclear Fusion Rate Study of a Muonic Molecule via Nuclear Threshold Resonances

NASA Astrophysics Data System (ADS)

Faghihi, F.; Eskandari, M. R.

This work follows our previous calculations of the ground state binding energy, size, and the effective nuclear charge of the muonic T3 molecule, using the Born-Oppenheimer adiabatic approximation. In our past articles, we showed that the system possesses two minimum positions, the first one at the muonic distance and the second at the atomic distance. Also, the symmetric planner vibrational model assumed between the two minima and the approximated potential were calculated. Following from the previous studies, we now calculate the fusion rate of the T3 muonic molecule according to the overlap integral of the resonance nuclear compound nucleus and the molecular wave functions.

Improved distorted wave theory with the localized virial conditions

NASA Astrophysics Data System (ADS)

Hahn, Y. K.; Zerrad, E.

2009-12-01

The distorted wave theory is operationally improved to treat the full collision amplitude, such that the corrections to the distorted wave Born amplitude can be systematically calculated. The localized virial conditions provide the tools necessary to test the quality of successive approximations at each stage and to optimize the solution. The details of the theoretical procedure are explained in concrete terms using a collisional ionization model and variational trial functions. For the first time, adjustable parameters associated with an approximate scattering solution can be fully determined by the theory. A small number of linear parameters are introduced to examine the convergence property and the effectiveness of the new approach.

The effect of density fluctuations on electron cyclotron beam broadening and implications for ITER

NASA Astrophysics Data System (ADS)

Snicker, A.; Poli, E.; Maj, O.; Guidi, L.; Köhn, A.; Weber, H.; Conway, G.; Henderson, M.; Saibene, G.

2018-01-01

We present state-of-the-art computations of propagation and absorption of electron cyclotron waves, retaining the effects of scattering due to electron density fluctuations. In ITER, injected microwaves are foreseen to suppress neoclassical tearing modes (NTMs) by driving current at the q=2 and q=3/2 resonant surfaces. Scattering of the beam can spoil the good localization of the absorption and thus impair NTM control capabilities. A novel tool, the WKBeam code, has been employed here in order to investigate this issue. The code is a Monte Carlo solver for the wave kinetic equation and retains diffraction, full axisymmetric tokamak geometry, determination of the absorption profile and an integral form of the scattering operator which describes the effects of turbulent density fluctuations within the limits of the Born scattering approximation. The approach has been benchmarked against the paraxial WKB code TORBEAM and the full-wave code IPF-FDMC. In particular, the Born approximation is found to be valid for ITER parameters. In this paper, we show that the radiative transport of EC beams due to wave scattering in ITER is diffusive unlike in present experiments, thus causing up to a factor of 2-4 broadening in the absorption profile. However, the broadening depends strongly on the turbulence model assumed for the density fluctuations, which still has large uncertainties.

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.

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

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.

Lung parenchyma at maturity is influenced by postnatal growth but not by moderate preterm birth in sheep.

PubMed

Maritz, Gert; Probyn, Megan; De Matteo, Robert; Snibson, Ken; Harding, Richard

2008-01-01

We have recently shown that moderate preterm birth, in the absence of respiratory support, altered the structure of lung parenchyma in young lambs, but the long-term effects are unknown. To determine whether structural changes persist to maturity, and whether postnatal growth affects lung structure at maturity in sheep. At approximately 1.2 years after birth, lung parenchyma of sheep born 14 days before term (n = 7) was stereologically compared with that of controls born at term (n = 8, term approx. 146 days). Preterm birth per se had no significant effect on lung volume, alveolar number and size, and thicknesses of the alveolar walls and blood-gas barrier. After combining the preterm and term groups, we examined the effects of postnatal growth rates on lung parenchyma. Slower-growing sheep (SG; n = 7: 4 preterm, 3 term) were compared with faster-growing sheep (FG; n = 8: 3 preterm, 5 term). At approximately 1.2 years, the right lung volume, relative to body weight, was significantly lower in SG than FG sheep (p < 0.05) and alveolar number was significantly lower by approximately 44%. The total alveolar internal surface area of the right lung of SG sheep was 38% smaller than in FG sheep; it was also significantly lower when related to both lung and body weight. Our data suggest that moderate preterm birth does not cause persistent alterations in lung parenchyma. However, slow postnatal growth in low-birth-weight sheep results in smaller lungs with fewer alveoli and a lower alveolar surface area relative to body weight. Copyright (c) 2007 S. Karger AG, Basel.

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…

The impact and implications of undocumented immigration on individual and collective health in the United States.

PubMed

Hilfinger Messias, DeAnne K; McEwen, Marylyn Morris; Clark, Lauren

2015-01-01

A nation of immigrants, the United States currently has more foreign-born residents than any other country; approximately 28% of these foreign-born residents are undocumented immigrants--individuals who either entered or are currently residing in the country without valid immigration or residency documents. The complex and constantly changing social, political, and economic context of undocumented migration has profound effects on individuals, families, and communities. The lack of demographic and epidemiologic data on undocumented immigrants is a major public health challenge. In this article, we identify multiple dimensions of vulnerability among undocumented persons; examine how undocumentedness impacts health and health care access and utilization; and consider the professional, practice, and policy issues and implications for nurses. Copyright © 2015 Elsevier Inc. All rights reserved.

Thermostating extended Lagrangian Born-Oppenheimer molecular dynamics.

PubMed

Martínez, Enrique; Cawkwell, Marc J; Voter, Arthur F; Niklasson, Anders M N

2015-04-21

Extended Lagrangian Born-Oppenheimer molecular dynamics is developed and analyzed for applications in canonical (NVT) simulations. Three different approaches are considered: the Nosé and Andersen thermostats and Langevin dynamics. We have tested the temperature distribution under different conditions of self-consistent field (SCF) convergence and time step and compared the results to analytical predictions. We find that the simulations based on the extended Lagrangian Born-Oppenheimer framework provide accurate canonical distributions even under approximate SCF convergence, often requiring only a single diagonalization per time step, whereas regular Born-Oppenheimer formulations exhibit unphysical fluctuations unless a sufficiently high degree of convergence is reached at each time step. The thermostated extended Lagrangian framework thus offers an accurate approach to sample processes in the canonical ensemble at a fraction of the computational cost of regular Born-Oppenheimer molecular dynamics simulations.

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.

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

Anharmonic phonon-phonon scattering modeling of three-dimensional atomistic transport: An efficient quantum treatment

NASA Astrophysics Data System (ADS)

Lee, Y.; Bescond, M.; Logoteta, D.; Cavassilas, N.; Lannoo, M.; Luisier, M.

2018-05-01

We propose an efficient method to quantum mechanically treat anharmonic interactions in the atomistic nonequilibrium Green's function simulation of phonon transport. We demonstrate that the so-called lowest-order approximation, implemented through a rescaling technique and analytically continued by means of the Padé approximants, can be used to accurately model third-order anharmonic effects. Although the paper focuses on a specific self-energy, the method is applicable to a very wide class of physical interactions. We apply this approach to the simulation of anharmonic phonon transport in realistic Si and Ge nanowires with uniform or discontinuous cross sections. The effect of increasing the temperature above 300 K is also investigated. In all the considered cases, we are able to obtain a good agreement with the routinely adopted self-consistent Born approximation, at a remarkably lower computational cost. In the more complicated case of high temperatures (≫300 K), we find that the first-order Richardson extrapolation applied to the sequence of the Padé approximants N -1 /N results in a significant acceleration of the convergence.

Electron-vibration entanglement in the Born-Oppenheimer description of chemical reactions and spectroscopy.

PubMed

McKemmish, Laura K; McKenzie, Ross H; Hush, Noel S; Reimers, Jeffrey R

2015-10-14

Entanglement is sometimes regarded as the quintessential measure of the quantum nature of a system and its significance for the understanding of coupled electronic and vibrational motions in molecules has been conjectured. Previously, we considered the entanglement developed in a spatially localized diabatic basis representation of the electronic states, considering design rules for qubits in a low-temperature chemical quantum computer. We extend this to consider the entanglement developed during high-energy processes. We also consider the entanglement developed using adiabatic electronic basis, providing a novel way for interpreting effects of the breakdown of the Born-Oppenheimer (BO) approximation. We consider: (i) BO entanglement in the ground-state wavefunction relevant to equilibrium thermodynamics, (ii) BO entanglement associated with low-energy wavefunctions relevant to infrared and tunneling spectroscopies, (iii) BO entanglement in high-energy eigenfunctions relevant to chemical reaction processes, and (iv) BO entanglement developed during reactive wavepacket dynamics. A two-state single-mode diabatic model descriptive of a wide range of chemical phenomena is used for this purpose. The entanglement developed by BO breakdown correlates simply with the diameter of the cusp introduced by the BO approximation, and a hierarchy appears between the various BO-breakdown correction terms, with the first-derivative correction being more important than the second-derivative correction which is more important than the diagonal correction. This simplicity is in contrast to the complexity of BO-breakdown effects on thermodynamic, spectroscopic, and kinetic properties. Further, processes poorly treated at the BO level that appear adequately treated using the Born-Huang adiabatic approximation are found to have properties that can only be described using a non-adiabatic description. For the entanglement developed between diabatic electronic states and the nuclear motion, qualitatively differently behavior is found compared to traditional properties of the density matrix and hence entanglement provides new information about system properties. For chemical reactions, this type of entanglement simply builds up as the transition-state region is crossed. It is robust to small changes in parameter values and is therefore more attractive for making quantum qubits than is the related fragile ground-state entanglement, provided that coherent motion at the transition state can be sustained.

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.

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.

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.

Birth order and physical fitness in early adulthood: evidence from Swedish military conscription data.

PubMed

Barclay, Kieron; Myrskylä, Mikko

2014-12-01

Physical fitness at young adult ages is an important determinant of physical health, cognitive ability, and mortality. However, few studies have addressed the relationship between early life conditions and physical fitness in adulthood. An important potential factor influencing physical fitness is birth order, which prior studies associate with several early- and later-life outcomes such as height and mortality. This is the first study to analyse the association between birth order and physical fitness in late adolescence. We use military conscription data on 218,873 Swedish males born between 1965 and 1977. Physical fitness is measured by a test of maximal working capacity, a measure of cardiovascular fitness closely related to V02max. We use linear regression with sibling fixed effects, meaning a within-family comparison, to eliminate the confounding influence of unobserved factors that vary between siblings. To understand the mechanism we further analyse whether the association between birth order and physical fitness varies by sibship size, parental socioeconomic status, birth cohort or length of the birth interval. We find a strong, negative and monotonic relationship between birth order and physical fitness. For example, third-born children have a maximal working capacity approximately 0.1 (p < 0.000) standard deviations lower than first-born children. The association exists both in small (3 or less children) and large families (4 or more children), in high and low socioeconomic status families, and amongst cohorts born in the 1960s and the 1970s. While in the whole population the birth order effect does not depend on the length of the birth intervals, in two-child families a longer birth interval strengthens the advantage of the first-born. Our results illustrate the importance of birth order for physical fitness, and suggest that the first-born advantage already arises in late adolescence. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Direct Measurement of Wave Kernels in Time-Distance Helioseismology

NASA Technical Reports Server (NTRS)

Duvall, T. L., Jr.

2006-01-01

Solar f-mode waves are surface-gravity waves which propagate horizontally in a thin layer near the photosphere with a dispersion relation approximately that of deep water waves. At the power maximum near 3 mHz, the wavelength of 5 Mm is large enough for various wave scattering properties to be observable. Gizon and Birch (2002,ApJ,571,966)h ave calculated kernels, in the Born approximation, for the sensitivity of wave travel times to local changes in damping rate and source strength. In this work, using isolated small magnetic features as approximate point-sourc'e scatterers, such a kernel has been measured. The observed kernel contains similar features to a theoretical damping kernel but not for a source kernel. A full understanding of the effect of small magnetic features on the waves will require more detailed modeling.

Thermostating extended Lagrangian Born-Oppenheimer molecular dynamics

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

Martínez, Enrique; Cawkwell, Marc J.; Voter, Arthur F.

Here, Extended Lagrangian Born-Oppenheimer molecular dynamics is developed and analyzed for applications in canonical (NVT) simulations. Three different approaches are considered: the Nosé and Andersen thermostats and Langevin dynamics. We have tested the temperature distribution under different conditions of self-consistent field (SCF) convergence and time step and compared the results to analytical predictions. We find that the simulations based on the extended Lagrangian Born-Oppenheimer framework provide accurate canonical distributions even under approximate SCF convergence, often requiring only a single diagonalization per time step, whereas regular Born-Oppenheimer formulations exhibit unphysical fluctuations unless a sufficiently high degree of convergence is reached atmore » each time step. Lastly, the thermostated extended Lagrangian framework thus offers an accurate approach to sample processes in the canonical ensemble at a fraction of the computational cost of regular Born-Oppenheimer molecular dynamics simulations.« less

Thermostating extended Lagrangian Born-Oppenheimer molecular dynamics

DOE PAGES

Martínez, Enrique; Cawkwell, Marc J.; Voter, Arthur F.; ...

2015-04-21

Here, Extended Lagrangian Born-Oppenheimer molecular dynamics is developed and analyzed for applications in canonical (NVT) simulations. Three different approaches are considered: the Nosé and Andersen thermostats and Langevin dynamics. We have tested the temperature distribution under different conditions of self-consistent field (SCF) convergence and time step and compared the results to analytical predictions. We find that the simulations based on the extended Lagrangian Born-Oppenheimer framework provide accurate canonical distributions even under approximate SCF convergence, often requiring only a single diagonalization per time step, whereas regular Born-Oppenheimer formulations exhibit unphysical fluctuations unless a sufficiently high degree of convergence is reached atmore » each time step. Lastly, the thermostated extended Lagrangian framework thus offers an accurate approach to sample processes in the canonical ensemble at a fraction of the computational cost of regular Born-Oppenheimer molecular dynamics simulations.« less

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.

Electric transition dipole moment in pre-Born-Oppenheimer molecular structure theory.

PubMed

Simmen, Benjamin; Mátyus, Edit; Reiher, Markus

2014-10-21

This paper presents the calculation of the electric transition dipole moment in a pre-Born-Oppenheimer framework. Electrons and nuclei are treated equally in terms of the parametrization of the non-relativistic total wave function, which is written as a linear combination of basis functions constructed from explicitly correlated Gaussian functions and the global vector representation. The integrals of the electric transition dipole moment are derived corresponding to these basis functions in both the length and the velocity representation. The calculations are performed in laboratory-fixed Cartesian coordinates without relying on coordinates which separate the center of mass from the translationally invariant degrees of freedom. The effect of the overall motion is eliminated through translationally invariant integral expressions. The electric transition dipole moment is calculated between two rovibronic levels of the H2 molecule assignable to the lowest rovibrational states of the X (1)Σ(g)(+) and B (1)Σ(u)(+) electronic states in the clamped-nuclei framework. This is the first evaluation of this quantity in a full quantum mechanical treatment without relying on the Born-Oppenheimer approximation.

Treecode-based generalized Born method

NASA Astrophysics Data System (ADS)

Xu, Zhenli; Cheng, Xiaolin; Yang, Haizhao

2011-02-01

We have developed a treecode-based O(Nlog N) algorithm for the generalized Born (GB) implicit solvation model. Our treecode-based GB (tGB) is based on the GBr6 [J. Phys. Chem. B 111, 3055 (2007)], an analytical GB method with a pairwise descreening approximation for the R6 volume integral expression. The algorithm is composed of a cutoff scheme for the effective Born radii calculation, and a treecode implementation of the GB charge-charge pair interactions. Test results demonstrate that the tGB algorithm can reproduce the vdW surface based Poisson solvation energy with an average relative error less than 0.6% while providing an almost linear-scaling calculation for a representative set of 25 proteins with different sizes (from 2815 atoms to 65456 atoms). For a typical system of 10k atoms, the tGB calculation is three times faster than the direct summation as implemented in the original GBr6 model. Thus, our tGB method provides an efficient way for performing implicit solvent GB simulations of larger biomolecular systems at longer time scales.

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.

Challenges facing effective implementation of co-trimoxazole prophylaxis in children born to HIV-infected mothers in the public health facilities.

PubMed

Kamuhabwa, Appolinary Ar; Manyanga, Vicky

2015-01-01

If children born to HIV-infected mothers are not identified early, approximately 30% of them will die within the first year of life due to opportunistic infections. In order to prevent morbidity and mortality due to opportunistic infections in children, the World Health Organization recommends the use of prophylaxis using co-trimoxazole. However, the challenges affecting effective implementation of this policy in Tanzania have not been documented. In this study, we assessed the challenges facing the provision of co-trimoxazole prophylaxis among children born to HIV-infected mothers in the public hospitals of Dar es Salaam, Tanzania. Four hundred and ninety-eight infants' PMTCT (Prevention of Mother-to-Child Transmission of HIV) register books for the past 2 years were reviewed to obtain information regarding the provision of co-trimoxazole prophylaxis. One hundred and twenty-six health care workers were interviewed to identify success stories and challenges in the provision of co-trimoxazole prophylaxis in children. In addition, 321 parents and guardians of children born to HIV-infected mothers were interviewed in the health facilities. Approximately 80% of children were initiated with co-trimoxazole prophylaxis within 2 months after birth. Two hundred and ninety-one (58.4%) children started using co-trimoxazole within 4 weeks after birth. Majority (n=458, 91.8%) of the children were prescribed 120 mg of co-trimoxazole per day, whereas 39 (7.8%) received 240 mg per day. Only a small proportion (n=1, 0.2%) of children received 480 mg/day. Dose determination was based on the child's age rather than body weight. Parents and guardians reported that 42 (13.1%) children had missed one or more doses of co-trimoxazole during the course of prophylaxis. The majority of health care workers (89.7%) reported that co-trimoxazole is very effective for the prevention of opportunistic infections among children, but frequent shortage of co-trimoxazole in the health facilities was the main challenge. Most children who were initiated with co-trimoxazole prophylaxis did not experience significant opportunistic infections, and the drug was well tolerated. The major barrier for co-trimoxazole prophylaxis was due to frequent out-of-stocks of pediatric co-trimoxazole formulations in the health facilities. Dose determination was based on the age rather than the weight of children, thus creating potential for under- or over-dosing of children.

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.

Statistics of optical vortex wander on propagation through atmospheric turbulence.

PubMed

Gu, Yalong

2013-04-01

The transverse position of an optical vortex on propagation through atmospheric turbulence is studied. The probability density of the optical vortex position on a transverse plane in the atmosphere is formulated in weak turbulence by using the Born approximation. With these formulas, the effect of aperture averaging on topological charge detection is investigated. These results provide quantitative guidelines for the design of an optimal detector of topological charge, which has potential application in optical vortex communication systems.

Effects of working memory training on children born preterm.

PubMed

Lee, Clara S C; Pei, Jacqueline; Andrew, Gail; A Kerns, Kimberly; Rasmussen, Carmen

2017-01-01

Researchers have reported benefits of working memory training in various populations, however, the training gains in preterm population is still inadequately studied. This study aimed to investigate the transfer and lasting effects of an online working memory training program on a group of preterm children aged between 4 and 6 years (mean gestational age = 28.3 weeks; mean birth weight = 1153 grams). Children were asked to perform the Cogmed JM at home for approximately 15 minutes a day, 5 days a week for 5 weeks. Their nontrained working memory and attention were assessed pre-training, post-training, and at 5-week follow-up. Parent ratings on children's executive functions were obtained at the three time points. Results revealed that significant improvements in verbal working memory was emerging in preterm children at 5-week follow-up, while significant gains in visuospatial working memory was found post-training and at 5-week follow-up in age-matched term-born children. These results indicated that working memory training has benefits on preterm children; however, the gains are different from those observed in term-born children. No significant differences in attention and parent-rated EF were found in either group across time. The possible explanations for the training benefits observed in preterm children were discussed.

Effects on reproduction in female offspring from Sprague-Dawley rats fed 10% snakeweed (Gutierrezia microcephala) throughout pregnancy and concurrent treatment with safflower oil.

PubMed

Staley, E C; Smith, G S; Greenberg, J A

1995-10-01

Previous studies determined that safflower oil administration provided protection against the embryotoxicity seen following ingestion of 10% snakeweed (Gutierrezia microcephala) throughout pregnancy. Sixty-two young primiparous female rats born in those studies were paired with adult male Sprague-Dawley rats. After 4 d they were removed and carried their litters to term. Observations were made of the presence and extent of reproductive effects attributable to the 10% snakeweed exposure and differences in fecundity that were attributable to dosing with safflower oil or normal saline during the snakeweed exposure. Of the 62 rats, 50 carried litters to term and approximated the reproductive efficiency of normal primiparous Sprague-Dawley rats. There was no significant difference between the fecundity of females born to rats fed the 10% snakeweed and dosed with safflower oil, those born of rats fed snakeweed dosed with normal saline, or those fed a snakeweed-free diet and dosed with normal saline. Regardless of the diet or treatment administered, dams carrying their litters to parturition gave birth to healthy, normo-reproductive offspring. While the toxic principles in Gutierrezia species plants may act as estrogenic or anti-estrogenic compounds, they did not impair fertility in the female offspring of dosed rats.

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

Instability of quantum equilibrium in Bohm's dynamics

PubMed Central

Colin, Samuel; Valentini, Antony

2014-01-01

We consider Bohm's second-order dynamics for arbitrary initial conditions in phase space. In principle, Bohm's dynamics allows for ‘extended’ non-equilibrium, with initial momenta not equal to the gradient of phase of the wave function (as well as initial positions whose distribution departs from the Born rule). We show that extended non-equilibrium does not relax in general and is in fact unstable. This is in sharp contrast with de Broglie's first-order dynamics, for which non-standard momenta are not allowed and which shows an efficient relaxation to the Born rule for positions. On this basis, we argue that, while de Broglie's dynamics is a tenable physical theory, Bohm's dynamics is not. In a world governed by Bohm's dynamics, there would be no reason to expect to see an effective quantum theory today (even approximately), in contradiction with observation. PMID:25383020

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.

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.

Do in vitro fertilization treatments result in healthy babies?

PubMed

Kaartinen, Noora; Tinkanen, Helena

In Finland, the proportion of children born as a result of in vitro fertilization treatments is annually approximately 3.3%, and the percentage proportion of the population is growing. Their general somatic health status and cognitive development do not differ from spontaneously fertilized children. In vitro fertilization treatments are, however, associated with a slightly elevated risk of preterm delivery, low birth weight and structural abnormalities. The risk of childhood cancer does not appear to be increased in IVF children. The in vitro fertilization process affects the embryonic epigenome, which organizes itself during early embryonic development. These changes may influence the phenotype and health profile of the unborn child. The effect of in vitro fertilization treatments on an individual's long-term health is poorly understood, requiring prospective follow-up studies with sufficiently large datasets. In vitro fertilization treatments are the most effective way to treat infertility, and the treatments are generally safe both for the future mother and the baby being born.

Edge turbulence effect on ultra-fast swept reflectometry core measurements in tokamak plasmas

NASA Astrophysics Data System (ADS)

Zadvitskiy, G. V.; Heuraux, S.; Lechte, C.; Hacquin, S.; Sabot, R.

2018-02-01

Ultra-fast frequency-swept reflectometry (UFSR) enables one to provide information about the turbulence radial wave-number spectrum and perturbation amplitude with good spatial and temporal resolutions. However, a data interpretation of USFR is quiet tricky. An iterative algorithm to solve this inverse problem was used in past works, Gerbaud (2006 Rev. Sci. Instrum. 77 10E928). For a direct solution, a fast 1D Helmholtz solver was used. Two-dimensional effects are strong and should be taken into account during data interpretation. As 2D full-wave codes are still too time consuming for systematic application, fast 2D approaches based on the Born approximation are of prime interest. Such methods gives good results in the case of small turbulence levels. However in tokamak plasmas, edge turbulence is usually very strong and can distort and broaden the probing beam Sysoeva et al (2015 Nucl. Fusion 55 033016). It was shown that this can change reflectometer phase response from the plasma core. Comparison between 2D full wave computation and the simplified Born approximation was done. The approximated method can provide a right spectral shape, but it is unable to describe a change of the spectral amplitude with an edge turbulence level. Computation for the O-mode wave with the linear density profile in the slab geometry and for realistic Tore-Supra density profile, based on the experimental data turbulence amplitude and spectrum, were performed to investigate the role of strong edge turbulence. It is shown that the spectral peak in the signal amplitude variation spectrum which rises with edge turbulence can be a signature of strong edge turbulence. Moreover, computations for misaligned receiving and emitting antennas were performed. It was found that the signal amplitude variation peak changes its position with a receiving antenna poloidal displacement.

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)

Progress on ultrasonic flaw sizing in turbine-engine rotor components: bore and web geometries

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

Rose, J.H.; Gray, T.A.; Thompson, R.B.

1983-01-01

The application of generic flaw-sizing techniques to specific components generally involves difficulties associated with geometrical complexity and simplifications arising from a knowledge of the expected flaw distribution. This paper is concerned with the case of ultrasonic flaw sizing in turbine-engine rotor components. The sizing of flat penny-shaped cracks in the web geometry discussed and new crack-sizing algorithms based on the Born and Kirchhoff approximations are introduced. Additionally, we propose a simple method for finding the size of a flat, penny-shaped crack given only the magnitude of the scattering amplitude. The bore geometry is discussed with primary emphasis on the cylindricalmore » focusing of the incident beam. Important questions which are addressed include the effects of diffraction and the position of the flaw with respect to the focal line. The appropriate deconvolution procedures to account for these effects are introduced. Generic features of the theory are compared with experiment. Finally, the effects of focused transducers on the Born inversion algorithm are discussed.« less

The effectiveness of copper oxide wire particles as an anthelmintic in pregnant ewes and safety to offspring.

PubMed

Burke, J M; Miller, J E; Brauer, D K

2005-08-10

The objective of the experiment was to determine the effectiveness of copper oxide wire particles (COWP) in pregnant ewes and safety to lambs. COWP have been used recently as an anthelmintic in small ruminants to overcome problems associated with nematode resistance to chemical dewormers. Doses of COWP (

Path integral molecular dynamics for exact quantum statistics of multi-electronic-state systems.

PubMed

Liu, Xinzijian; Liu, Jian

2018-03-14

An exact approach to compute physical properties for general multi-electronic-state (MES) systems in thermal equilibrium is presented. The approach is extended from our recent progress on path integral molecular dynamics (PIMD), Liu et al. [J. Chem. Phys. 145, 024103 (2016)] and Zhang et al. [J. Chem. Phys. 147, 034109 (2017)], for quantum statistical mechanics when a single potential energy surface is involved. We first define an effective potential function that is numerically favorable for MES-PIMD and then derive corresponding estimators in MES-PIMD for evaluating various physical properties. Its application to several representative one-dimensional and multi-dimensional models demonstrates that MES-PIMD in principle offers a practical tool in either of the diabatic and adiabatic representations for studying exact quantum statistics of complex/large MES systems when the Born-Oppenheimer approximation, Condon approximation, and harmonic bath approximation are broken.

Path integral molecular dynamics for exact quantum statistics of multi-electronic-state systems

NASA Astrophysics Data System (ADS)

Liu, Xinzijian; Liu, Jian

2018-03-01

An exact approach to compute physical properties for general multi-electronic-state (MES) systems in thermal equilibrium is presented. The approach is extended from our recent progress on path integral molecular dynamics (PIMD), Liu et al. [J. Chem. Phys. 145, 024103 (2016)] and Zhang et al. [J. Chem. Phys. 147, 034109 (2017)], for quantum statistical mechanics when a single potential energy surface is involved. We first define an effective potential function that is numerically favorable for MES-PIMD and then derive corresponding estimators in MES-PIMD for evaluating various physical properties. Its application to several representative one-dimensional and multi-dimensional models demonstrates that MES-PIMD in principle offers a practical tool in either of the diabatic and adiabatic representations for studying exact quantum statistics of complex/large MES systems when the Born-Oppenheimer approximation, Condon approximation, and harmonic bath approximation are broken.

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.

Two-proton transfer reactions on even Ni and Zn isotopes

NASA Astrophysics Data System (ADS)

Boucenna, A.; Kraus, L.; Linck, I.; Chan, Tsan Ung

1990-10-01

New levels strongly excited by 112-MeV 12C ions on even Ni and Zn isotopes are Jπ assigned on kinematical and geometrical arguments, crude shell-model calculations, and distorted-wave Born approximation angular-distribution analysis. These tentative assignments are supported by the Bansal-French model. Because of the contribution of additional collective effects, the two-proton transfer reaction spectra are less selectively fed than those obtained with the analogous two-neutron transfer reactions induced on the same targets in a similar energy range.

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.

Microwave scattering and emission from a half-space anisotropic random medium

NASA Astrophysics Data System (ADS)

Mudaliar, Saba; Lee, Jay Kyoon

1990-12-01

This paper is a sequel to an earlier paper (Lee and Mudaliar, 1988) where the backscattering coefficients of a half-space anisotropic random medium were obtained. Here the bistatic scattering coefficients are calculated by solving the modified radiative transfer equations under a first-order approximation. The effects of multiple scattering on the results are observed. Emissivities are calculated and compared with those obtained using the Born approximation (single scattering). Several interesting properties of the model are brought to notice using numerical examples. Finally, as an application, the theory is used to interpret the passive remote sensing data of multiyear sea ice in the microwave frequency range. A quite close agreement between theoretical prediction and the measured data is found.

Breakup effects on alpha spectroscopic factors of 16O

NASA Astrophysics Data System (ADS)

Adhikari, S.; Basu, C.; Sugathan, P.; Jhinghan, A.; Behera, B. R.; Saneesh, N.; Kaur, G.; Thakur, M.; Mahajan, R.; Dubey, R.; Mitra, A. K.

2017-01-01

The triton angular distribution for the 12C(7Li,t)16O* reaction is measured at 20 MeV, populating discrete states of 16O. Continuum discretized coupled reaction channel calculations are used to to extract the alpha spectroscopic properties of 16O states instead of the distorted wave born approximation theory to include the effects of breakup on the transfer process. The alpha reduced width, spectroscopic factors and the asymptotic normalization constant (ANC) of 16O states are extracted. The error in the spectroscopic factor is about 35% and in that of the ANC about 27%.

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.

Born-Oppenheimer approximation for a singular system

NASA Astrophysics Data System (ADS)

Akbas, Haci; Turgut, O. Teoman

2018-01-01

We discuss a simple singular system in one dimension, two heavy particles interacting with a light particle via an attractive contact interaction and not interacting among themselves. It is natural to apply the Born-Oppenheimer approximation to this problem. We present a detailed discussion of this approach; the advantage of this simple model is that one can estimate the error terms self-consistently. Moreover, a Fock space approach to this problem is presented where an expansion can be proposed to get higher order corrections. A slight modification of the same problem in which the light particle is relativistic is discussed in a later section by neglecting pair creation processes. Here, the second quantized description is more challenging, but with some care, one can recover the first order expression exactly.

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.

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

Electron-positron pair production in ion collisions at low velocity beyond Born approximation

NASA Astrophysics Data System (ADS)

Lee, R. N.; Milstein, A. I.

2016-10-01

We derive the spectrum and the total cross section of electromagnetic e+e- pair production in the collisions of two nuclei at low relative velocity β. Both free-free and bound-free e+e- pair production is considered. The parameters ηA,B =ZA,B α are assumed to be small compared to unity but arbitrary compared to β (ZA,B are the charge numbers of the nuclei and α is the fine structure constant). Due to a suppression of the Born term by high power of β, the first Coulomb correction to the amplitude appears to be important at ηA,B ≳ β. The effect of a finite nuclear mass is discussed. In contrast to the result obtained in the infinite nuclear mass limit, the terms ∝M-2 are not suppressed by the high power of β and may easily dominate at sufficiently small velocities.

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.

Increasing lung cancer death rates among young women in southern and midwestern States.

PubMed

Jemal, Ahmedin; Ma, Jiemin; Rosenberg, Philip S; Siegel, Rebecca; Anderson, William F

2012-08-01

Previous studies reported that declines in age-specific lung cancer death rates among women in the United States abruptly slowed in women younger than age 50 years (ie, women born after the 1950s). However, in view of substantial geographic differences in antitobacco measures and sociodemographic factors that affect smoking prevalence, it is unknown whether this change in the trend was similar across all states. We examined female age-specific lung cancer death rates (1973 through 2007) by year of death and birth in each state by using age-period-cohort models. Cohort relative risks adjusted for age and period effects were used to compare the lung cancer death rate for a given birth cohort to a referent birth cohort (ie, the 1933 cohort herein). Age-specific lung cancer death rates declined continuously in white women in California, but the rates declined less quickly or even increased in the remaining states among women younger than age 50 years and women born after the 1950s, especially in several southern and midwestern states. For example, in some southern states (eg, Alabama), lung cancer death rates among women born in the 1960s were approximately double those of women born in the 1930s. The unfavorable lung cancer trend in white women born after circa 1950 in southern and midwestern states underscores the need for additional interventions to promote smoking cessation in these high-risk populations, which could lead to more favorable future mortality trends for lung cancer and other smoking-related diseases.

Increasing Lung Cancer Death Rates Among Young Women in Southern and Midwestern States

PubMed Central

Jemal, Ahmedin; Ma, Jiemin; Rosenberg, Philip S.; Siegel, Rebecca; Anderson, William F.

2012-01-01

Purpose Previous studies reported that declines in age-specific lung cancer death rates among women in the United States abruptly slowed in women younger than age 50 years (ie, women born after the 1950s). However, in view of substantial geographic differences in antitobacco measures and sociodemographic factors that affect smoking prevalence, it is unknown whether this change in the trend was similar across all states. Methods We examined female age-specific lung cancer death rates (1973 through 2007) by year of death and birth in each state by using age-period-cohort models. Cohort relative risks adjusted for age and period effects were used to compare the lung cancer death rate for a given birth cohort to a referent birth cohort (ie, the 1933 cohort herein). Results Age-specific lung cancer death rates declined continuously in white women in California, but the rates declined less quickly or even increased in the remaining states among women younger than age 50 years and women born after the 1950s, especially in several southern and midwestern states. For example, in some southern states (eg, Alabama), lung cancer death rates among women born in the 1960s were approximately double those of women born in the 1930s. Conclusion The unfavorable lung cancer trend in white women born after circa 1950 in southern and midwestern states underscores the need for additional interventions to promote smoking cessation in these high-risk populations, which could lead to more favorable future mortality trends for lung cancer and other smoking-related diseases. PMID:22734032

Importance of Vibronic Effects in the UV-Vis Spectrum of the 7,7,8,8-Tetracyanoquinodimethane Anion.

PubMed

Tapavicza, Enrico; Furche, Filipp; Sundholm, Dage

2016-10-11

We present a computational method for simulating vibronic absorption spectra in the ultraviolet-visible (UV-vis) range and apply it to the 7,7,8,8-tetracyanoquinodimethane anion (TCNQ - ), which has been used as a ligand in black absorbers. Gaussian broadening of vertical electronic excitation energies of TCNQ - from linear-response time-dependent density functional theory produces only one band, which is qualitatively incorrect. Thus, the harmonic vibrational modes of the two lowest doublet states were computed, and the vibronic UV-vis spectrum was simulated using the displaced harmonic oscillator approximation, the frequency-shifted harmonic oscillator approximation, and the full Duschinsky formalism. An efficient real-time generating function method was implemented to avoid the exponential complexity of conventional Franck-Condon approaches to vibronic spectra. The obtained UV-vis spectra for TCNQ - agree well with experiment; the Duschinsky rotation is found to have only a minor effect on the spectrum. Born-Oppenheimer molecular dynamics simulations combined with calculations of the electronic excitation energies for a large number of molecular structures were also used for simulating the UV-vis spectrum. The Born-Oppenheimer molecular dynamics simulations yield a broadening of the energetically lowest peak in the absorption spectrum, but additional vibrational bands present in the experimental and simulated quantum harmonic oscillator spectra are not observed in the molecular dynamics simulations. Our results underline the importance of vibronic effects for the UV-vis spectrum of TCNQ - , and they establish an efficient method for obtaining vibronic spectra using a combination of linear-response time-dependent density functional theory and a real-time generating function approach.

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.

Distorted-wave born approximation calculations for turbulence scattering in an upward-refracting atmosphere

NASA Technical Reports Server (NTRS)

Gilbert, Kenneth E.; Di, Xiao; Wang, Lintao

1990-01-01

Weiner and Keast observed that in an upward-refracting atmosphere, the relative sound pressure level versus range follows a characteristic 'step' function. The observed step function has recently been predicted qualitatively and quantitatively by including the effects of small-scale turbulence in a parabolic equation (PE) calculation. (Gilbert et al., J. Acoust. Soc. Am. 87, 2428-2437 (1990)). The PE results to single-scattering calculations based on the distorted-wave Born approximation (DWBA) are compared. The purpose is to obtain a better understanding of the physical mechanisms that produce the step-function. The PE calculations and DWBA calculations are compared to each other and to the data of Weiner and Keast for upwind propagation (strong upward refraction) and crosswind propagation (weak upward refraction) at frequencies of 424 Hz and 848 Hz. The DWBA calculations, which include only single scattering from turbulence, agree with the PE calculations and with the data in all cases except for upwind propagation at 848 Hz. Consequently, it appears that in all cases except one, the observed step function can be understood in terms of single scattering from an upward-refracted 'skywave' into the refractive shadow zone. For upwind propagation at 848 Hz, the DWBA calculation gives levels in the shadow zone that are much below both the PE and the data.

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

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.

Computational applications of the many-interacting-worlds interpretation of quantum mechanics.

PubMed

Sturniolo, Simone

2018-05-01

While historically many quantum-mechanical simulations of molecular dynamics have relied on the Born-Oppenheimer approximation to separate electronic and nuclear behavior, recently a great deal of interest has arisen in quantum effects in nuclear dynamics as well. Due to the computational difficulty of solving the Schrödinger equation in full, these effects are often treated with approximate methods. In this paper, we present an algorithm to tackle these problems using an extension to the many-interacting-worlds approach to quantum mechanics. This technique uses a kernel function to rebuild the probability density, and therefore, in contrast with the approximation presented in the original paper, it can be naturally extended to n-dimensional systems. This opens up the possibility of performing quantum ground-state searches with steepest-descent methods, and it could potentially lead to real-time quantum molecular-dynamics simulations. The behavior of the algorithm is studied in different potentials and numbers of dimensions and compared both to the original approach and to exact Schrödinger equation solutions whenever possible.

A review of electron-nucleus bremsstrahlung cross sections between 1 and 10 MeV

NASA Astrophysics Data System (ADS)

Mangiarotti, A.; Martins, M. N.

2017-12-01

More than 80 years have passed since the first calculations of electron-nucleus bremsstrahlung cross sections were published by Sommerfeld, for non-relativistic electrons, and, independently, by Sauter, Bethe and Heitler, and Racah, for relativistic electrons. The Bethe-Heitler expression, that is based on the first Born approximation and includes the screening of the Coulomb field of the nucleus by the atomic electrons, has proven to work well at moderately high energies where the Landau-Pomeranchuk-Migdal effect is negligible. We review the current theoretical and experimental status with a highlight on electrons with kinetic energies between 1 and 10 MeV. The choice is motivated by the peculiar difficulties present in this energy region, where it is necessary to treat simultaneously the interaction with the Coulomb field beyond the first Born approximation and the effect of screening. A fully numerical approach within the S-matrix formalism has proven to be extremely difficult above a few MeV, because the number of partial waves needed for an accurate evaluation is prohibitively large. Here we focus on analytic results, including the more complex ones employing the Furry-Sommerfeld-Maue wave functions and taking into account the next-to-leading order, and discuss the advantages and limitations in light of the best available data. The influence of multiple scattering in the target is investigated under the actual experimental conditions. A comparison with the widely used cross section tabulations by Seltzer and Berger is also presented.

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.

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.

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.

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

Electronic wave function and binding effects in M-shell ionization of gold by protons

NASA Astrophysics Data System (ADS)

Pajek, M.; Banaś, D.; Jabłoński, Ł.; Mukoyama, T.

2018-02-01

The measured M-X-ray production cross sections for protons, which are used in the particle induced X-ray emission (PIXE) technique, are systematically underestimated for low impact energies by the ECPSSR and ECUSAR theories. These theories, which are based on the plane wave Born approximation (PWBA) and use the screened hydrogenic wave functions, include corrections for the projectile Coulomb deflection and electron relativistic and binding effects. In the present paper, in order to interpret the observed disagreement at low impact energies, the systematic calculations of the M-shell ionization cross sections for gold were performed using the semiclassical (SCA) and the binary encounter (BEA) approximations in order to identify a role of the electronic wave function and electron binding effects. In these calculations the different wave functions, from nonrelativistic hydrogenic to selfconsistent Dirac-Hartree-Fock, were considered and the binding effect was treated within extreme separated- (SA) and united-atoms (UA) limits. The results are discussed in details and the observed discrepancies are attributed to inadequate description of the electron binding effect at the lowest impact energies for which the molecular approach is required.

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.

Natural history of severe thrombocytopenia in infectious mononucleosis

PubMed Central

Wong, Su Yong; Bennett, Bruce

1982-01-01

The natural history of severe thrombocytopenia in two patients with infectious mononucleosis (minimum platelet counts under 10 × 109 and 17 × 109/l respectively) is described. In both, the platelet count rose rapidly and spontaneously, reaching approximately 100 × 109/l on the seventh day. Bleeding symptoms were also transient and never life-threatening. The possibility of very rapid spontaneous recovery from severe thrombocytopenia must be borne in mind in assessing the effect of any drug in the management of this complication of infectious mononucleosis. PMID:7111109

Two-proton transfer reactions on even Ni and Zn isotopes

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

Boucenna, A.; Kraus, L.; Linck, I.

New levels strongly excited by 112-MeV {sup 12}C ions on even Ni and Zn isotopes are {ital J}{sup {pi}} assigned on kinematical and geometrical arguments, crude shell-model calculations, and distorted-wave Born approximation angular-distribution analysis. These tentative assignments are supported by the Bansal-French model. Because of the contribution of additional collective effects, the two-proton transfer reaction spectra are less selectively fed than those obtained with the analogous two-neutron transfer reactions induced on the same targets in a similar energy range.

Active microwave remote sensing of an anisotropic random medium layer

NASA Technical Reports Server (NTRS)

Lee, J. K.; Kong, J. A.

1985-01-01

A two-layer anisotropic random medium model has been developed to study the active remote sensing of the earth. The dyadic Green's function for a two-layer anisotropic medium is developed and used in conjunction with the first-order Born approximation to calculate the backscattering coefficients. It is shown that strong cross-polarization occurs in the single scattering process and is indispensable in the interpretation of radar measurements of sea ice at different frequencies, polarizations, and viewing angles. The effects of anisotropy on the angular responses of backscattering coefficients are also illustrated.

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.

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.

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.

Effect of maternal smoking cessation before and during early pregnancy on fetal and childhood growth.

PubMed

Suzuki, Kohta; Sato, Miri; Zheng, Wei; Shinohara, Ryoji; Yokomichi, Hiroshi; Yamagata, Zentaro

2014-01-01

Maternal smoking during pregnancy is a major cause of intrauterine growth restriction and childhood obesity, but only a few studies have examined the association of smoking cessation before and during pregnancy with fetal and childhood growth. We examined this association in a prospective cohort study in Japan. Our study included children born between 1991 and 2006 and their mothers. Using a questionnaire, maternal smoking status was recorded at pregnancy. The anthropometric data of the children were collected during a medical check-up at age 3 years. Multiple linear and logistic regression models were used for data analysis stratified by sex. In total, 2663 mothers reported their smoking status during early pregnancy, and data were collected from 2230 (83.7%) children at age 3 years. Maternal smoking during pregnancy was associated with a significant reduction in birth weight (approximately 120-150 g). Body mass index at age 3 years was significantly higher among boys born to smoking mothers than among boys born to nonsmoking mothers. Maternal smoking during pregnancy was associated with overweight at age 3 years among boys (adjusted odds ratio, 2.4; 95% CI, 1.03-5.4). However, among women who stopped smoking in early pregnancy, there was no increase in the risks of a small for gestational age birth or childhood overweight at age 3 years. Children born to mothers who stopped smoking before or during early pregnancy had appropriate fetal and childhood growth.

Spectroscopy of exotic hadrons formed from dynamical diquarks

NASA Astrophysics Data System (ADS)

Lebed, Richard F.

2017-12-01

The dynamical diquark picture asserts that exotic hadrons can be formed from widely separated colored diquark or triquark components. We use the Born-Oppenheimer (BO) approximation to study the spectrum of states thus constructed, both in the basis of diquark spins and in the basis of heavy quark-antiquark spins. We develop a compact notation for naming these states, and use the results of lattice simulations for hybrid mesons to predict the lowest expected BO potentials for both tetraquarks and pentaquarks. We then compare to the set of exotic candidates with experimentally determined quantum numbers, and find that all of them can be accommodated. Once decay modes are also considered, one can develop selection rules of both exact (JP C conservation) and approximate (within the context of the BO approximation) types and test their effectiveness. We find that the most appealing way to satisfy both sets of selection rules requires including additional low-lying BO potentials, a hypothesis that can be checked on the lattice.

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.

120 DEG C Cure, Durable, Corrosion Protection Powder Coatings for Temperature Sensitive Substrates

DTIC Science & Technology

2005-01-28

Extrudate was passed through water-cooled pinch-rolls and collected onto a stainless steel belt; from exit of the extruder, approximately 60 sec... stainless steel belt; from exit of the extruder, approximately 60 sec. was required to reach ambient temperature. Production scale processing at...inherently free from volatile organic compounds, chromates, and hazardous air pollutants. Relative to the incumbent solvent-borne urethane paint

Prevalence of small for gestational age (SGA) and short stature in children born SGA who qualify for growth hormone treatment at 3 years of age: Population-based study.

PubMed

Fujita, Kaori; Nagasaka, Miwako; Iwatani, Sota; Koda, Tsubasa; Kurokawa, Daisuke; Yamana, Keiji; Nishida, Kosuke; Taniguchi-Ikeda, Mariko; Uchino, Eiko; Shirai, Chika; Iijima, Kazumoto; Morioka, Ichiro

2016-05-01

To treat children born small for gestational age (SGA) with severe short stature, treatment with growth hormone (GH) has been approved in the USA, Europe, and Japan, but no population-based studies have reported their prevalence. The aims of this study were to investigate the prevalence of SGA and short stature in children born SGA who qualify for GH treatment at 3 years of age in a Japanese population. A population-based study was conducted in Kobe, Japan with 27 228 infants who were born between 2006 and 2008 and followed until 3 years of age. Prevalence of birthweight (BW) or birth length (BL) ≤ -2.0 standard deviation scores (SDS) for gestational age (GA; definition of SGA) was calculated. Short children born SGA who qualify for GH treatment at 3 years of age were estimated using the following criteria: BW and BL below the 10th percentile for GA, BW or BL ≤ -2.0 SDS for GA, and 2.5 SDS below the mean height for age. The prevalence of SGA was 3.5%. The estimated prevalence of short stature in children born SGA who met the criteria for GH treatment was 0.06%. The prevalence in infants born <34 weeks (0.39%) was significantly higher than that in infants born 34-41 weeks GA (0.05%, P = 0.02). The prevalence of SGA and short stature in children born SGA who qualify for GH treatment is approximately 1 of 30 infants and 1 of 1800 children, respectively. The risk is increased when children are born <34 weeks GA. © 2015 Japan Pediatric Society.

Cross sections of relativistic radiative electron capture by use of the strong-potential Born calculation

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

Hino, K.; Watanabe, T.

1987-07-15

The relativistically extended strong-potential Born (SPB) formalism is applied to the radiative electron capture process caused by the bombardment of a heavy and highly stripped charged particle with relativistically high velocity. The results are compared with those by use of nonrelativistic SPB calculations and with those by use of the relativistic Born calculation (Sauter's formula), which includes no distortion effects between a heavy projectile ion and an active electron. Even if the strong distortion effects are taken into consideration, the shapes of photon angular distributions in the laboratory frame still nearly depend on sin/sup 2/theta/sub L/(theta/sub L/ is the anglemore » of the emitted photon) in the vicinity of the angle of 90/sup 0/, which is the same as the results by use of Sauter's formula. The higher the charge of a projectile ion becomes, however, the greater the discrepancy between the angular shape of our results and that of Sauter's becomes at both smaller and larger angles than at 90/sup 0/. As is expected, the magnitudes of the differential and the total cross sections are drastically influenced by the distortion effects ascribable to a large charge of a heavy projectile ion such as U/sup 92+/. Our results are in good agreement with recent experiments. In addition, the Coulomb off-shell factor introduced by the SPB theory is found playing important roles in the case of the relativistic radiative electron capture process because the results calculated by using the relativistic impulse approximation are too underestimated.« less

Elastic and inelastic scattering of /sup 58/Ni+/sup 208/Pb at bombarding energies from 598 to 1011 MeV

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

Beckerman, M.; Auble, R.L.; Bertrand, F.E.

1987-08-01

High-resolution measurements have been made of elastic and inelastic scattering of /sup 58/Ni+ /sup 208/Pb at four bombarding energies from 10.3 to 17.4 MeV/nucleon. The considerable inelastic strength observed for excitation energies up to at least 7 MeV is dominated by Coulomb-driven quadrupole transitions. Analyses were done using both the distorted-wave Born approximation and coupled-channels models. At the highest bombarding energies the data can be described equally well by distorted-wave Born approximations and coupled channels analyses. We find that B(E2) = 0.062 e/sup 2/b/sup 2/ for the 1.454 MeV 2/sup +/ state in /sup 58/Ni and B(E2) = 0.34 e/supmore » 2/b/sup 2/ for the 4.09 MeV 2/sup +/ state in /sup 208/Pb.« less

u d b \\xAF b \\xAF tetraquark resonances with lattice QCD potentials and the Born-Oppenheimer approximation

NASA Astrophysics Data System (ADS)

Bicudo, Pedro; Cardoso, Marco; Peters, Antje; Pflaumer, Martin; Wagner, Marc

2017-09-01

We study tetraquark resonances with lattice QCD potentials computed for a static b ¯b ¯ pair in the presence of two lighter quarks u d , the Born-Oppenheimer approximation and the emergent wave method. As a proof of concept we focus on the system with isospin I =0 , but consider different relative angular momenta l of the heavy quarks b ¯b ¯. For l =0 a bound state has already been predicted with quantum numbers I (JP)=0 (1+). Exploring various angular momenta we now compute the phase shifts and search for S and T matrix poles in the second Riemann sheet. We predict a tetraquark resonance for l =1 , decaying into two B mesons, with quantum numbers I (JP)=0 (1-) , mass m =10 57 6-4+4 MeV and decay width Γ =11 2-103+90 MeV .

On proton excitation of forbidden lines in positive ions

NASA Astrophysics Data System (ADS)

Burgess, Alan; Tully, John A.

2005-08-01

The semi-classical impact parameter approximations used by Bahcall and Wolf and by Bely and Faucher, for proton excitation of electric quadrupole transitions in positive ions, both fail at high energies, giving cross sections which do not fall off correctly as constant/E. This is in contrast with the pioneering example of Seaton for Fe+13 and of Reid and Schwarz for S+3, both of whom achieve the correct functional form, but do not ensure the correct constant of proportionality. By combining the Born and semi-classical approximations one can obtain cross sections which have the full correct behaviour as E → ∞, and hence, rate coefficients which have the correct high temperature behaviour (~C/T1/2 with the correct value of C). We provide a computer program for calculating these. An error in Faucher's derivation of the Born formula is also discussed.

Born distorted-wave approximation applied to the H+ + He collisions at intermediate and high energies

NASA Astrophysics Data System (ADS)

Rahmanian, M.; Fathi, R.; Shojaei, F.

2017-11-01

The single-charge transfer process in collision of protons with helium atoms in their ground states is investigated. The model utilizes the second-order three-body Born distorted-wave approximation (BDW-3B) with correct Coulomb boundary conditions to calculate the differential and total cross sections at intermediate and high energies. The role of the passive electrons and electron-electron correlations are studied by comparing our results and the BDW-4B calculations with the complete perturbation potential. The present results are also compared with other theories, and the Thomas scattering mechanism is investigated. The obtained results are also compared with the recent experimental measurements. For the prior differential cross sections, the comparisons show better agreement with the experiments at smaller scattering angles. The agreement between the total cross sections and the BDW-4B results as well as the experimental data is good at higher impact energies.

The He+H¯→He p¯+e+ rearrangement

NASA Astrophysics Data System (ADS)

Todd, Allan C.; Armour, Edward A. G.

2006-06-01

In this paper, we present a summary of our work in progress on calculating cross sections for the He+H¯→He p¯+e+ rearrangement process in He H¯ scattering. This has involved a study of the system He p¯ within the Born-Oppenheimer (BO) approximation using the Rayleigh-Ritz variational method. This work has been reported in [A.C. Todd, E.A.G. Armour, J. Phys. B 38 (2005) 3367] and is summarised here. Similar calculations are in progress for the He+H¯ entrance channel. We intend to use the entrance channel and rearrangement channel wave functions to obtain the cross sections for the rearrangement using the distorted wave Born approximation T-matrix method described elsewhere in these proceedings [E.A.G. Armour, S. Jonsell, Y. Liu, A.C. Todd, these Proceedings, doi:10.1016/j.nimb.2006.01.049].

High-frequency Born synthetic seismograms based on coupled normal modes

USGS Publications Warehouse

Pollitz, Fred F.

2011-01-01

High-frequency and full waveform synthetic seismograms on a 3-D laterally heterogeneous earth model are simulated using the theory of coupled normal modes. The set of coupled integral equations that describe the 3-D response are simplified into a set of uncoupled integral equations by using the Born approximation to calculate scattered wavefields and the pure-path approximation to modulate the phase of incident and scattered wavefields. This depends upon a decomposition of the aspherical structure into smooth and rough components. The uncoupled integral equations are discretized and solved in the frequency domain, and time domain results are obtained by inverse Fourier transform. Examples show the utility of the normal mode approach to synthesize the seismic wavefields resulting from interaction with a combination of rough and smooth structural heterogeneities. This approach is applied to an ∼4 Hz shallow crustal wave propagation around the site of the San Andreas Fault Observatory at Depth (SAFOD).

Higher-Order Extended Lagrangian Born-Oppenheimer Molecular Dynamics for Classical Polarizable Models.

PubMed

Albaugh, Alex; Head-Gordon, Teresa; Niklasson, Anders M N

2018-02-13

Generalized extended Lagrangian Born-Oppenheimer molecular dynamics (XLBOMD) methods provide a framework for fast iteration-free simulations of models that normally require expensive electronic ground state optimizations prior to the force evaluations at every time step. XLBOMD uses dynamically driven auxiliary degrees of freedom that fluctuate about a variationally optimized ground state of an approximate "shadow" potential which approximates the true reference potential. While the requirements for such shadow potentials are well understood, constructing such potentials in practice has previously been ad hoc, and in this work, we present a systematic development of XLBOMD shadow potentials that match the reference potential to any order. We also introduce a framework for combining friction-like dissipation for the auxiliary degrees of freedom with general-order integration, a combination that was not previously possible. These developments are demonstrated with a simple fluctuating charge model and point induced dipole polarization models.

Angiotensin-converting enzyme genotype and arterial oxygen saturation at high altitude in Peruvian Quechua.

PubMed

Bigham, Abigail W; Kiyamu, Melisa; León-Velarde, Fabiola; Parra, Esteban J; Rivera-Ch, Maria; Shriver, Mark D; Brutsaert, Tom D

2008-01-01

The I-allele of the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been associated with performance benefits at high altitude (HA). In n = 142 young males and females of largely Quechua origins in Peru, we evaluated 3 specific hypotheses with regard to the HA benefits of the I-allele: (1) the I-allele is associated with higher arterial oxygen saturation (Sa(O(2))) at HA, (2) the I-allele effect depends on the acclimatization state of the subjects, and (3) the putative I-allele effect on Sa(O(2)) is mediated by the isocapnic hypoxic ventilatory response (HVR, l/min(1)/% Sa(O(2))(1)). The subject participants comprised two different study groups including BLA subjects (born at low altitude) who were lifelong sea-level residents transiently exposed to hypobaric hypoxia (<24 h) and BHA subjects (born at HA) who were lifelong residents of HA. To control for the possibility of population stratification, Native American ancestry proportion (NAAP) was estimated as a covariate for each individual using a panel of 70 ancestry-informative molecular markers (AIMS). At HA, resting and exercise Sa(O(2)) was strongly associated with the ACE genotype, p = 0.008 with approximately 4% of the total variance in Sa(O(2)) attributed to ACE genotype. Moreover, I/I individuals maintained approximately 2.3 percentage point higher Sa(O(2)) compared to I/D and D/D. This I-allele effect was evident in both BLA and BHA groups, suggesting that acclimatization state has little influence on the phenotypic expression of the ACE gene. Finally, ACE genotype was not associated with the isocapnic HVR, although HVR had a strong independent effect on Sa(O(2)) (p = 0.001). This suggests that the I-allele effect on Sa(O(2)) is not mediated by the peripheral control of breathing, but rather by some other central cardiopulmonary effect of the ACE gene on the renin-angiotensin-aldosterone system (RAAS).

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.

M-shell x-ray production cross sections for 19 elements in the range Z=54-92 by H/sup +/, He/sup +/ and He/sup + +/ ions from 300 keV to 40 MeV. [Xe, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Hf, Ta, W, Pt, Au, Hg, Pb, Bi, and U

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

Mehta, R.; Duggan, J.L.; Kocur, P.M.

1983-04-01

In this report, the measurements done over the last three decades at various laboratories are surveyed. The elements studied were Xe, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Hf, Ta, W, Pt, Au, Hg, Pb, Bi, and U. The projectile energies investigated range from 300 keV to 40 MeV for the protons and 250 keV to 2.5 MeV for He/sup +/ ions. Also reported are the M-shell x-ray production cross sections of some rare-earth elements recently measured at NTSU. For these measurements the energy of incident /sup 1/H/sup +/ and /sup 4/He/sup +/ ions ranged from 0.25 tomore » 2.5 MeV. The experimental data are compared to the M-shell ionization cross section predictions of first Born approximation, i.e. the PWBA for direct ionization plus the OBK of Nikolaev for electron capture. Comparison is also made with the theory by Brandt and Lapicki that goes beyond the first Born approximation, i.e. the ECPSSR approach which accounts for the Energy loss, Coulomb deflection and Relativistic effects in the Perturbed Stationary State theory.« less

Does a parent-administrated early motor intervention influence general movements and movement character at 3months of age in infants born preterm?

PubMed

Fjørtoft, Toril; Ustad, Tordis; Follestad, Turid; Kaaresen, Per Ivar; Øberg, Gunn Kristin

2017-09-01

Studies of preterm and term-born infants have shown absent fidgety movements and an abnormal movement character to be related to brain lesions and unfavourable neurological outcomes. The present study examines what effect a parent-administered early intervention program applied to preterm infants in a randomised control trial (RCT) between 34 and 36weeks gestational age has on their fidgety movements and overall movement character at three months of age. The study was part of the RCT in an early intervention programme including preterm infants born between 2010 and 2014 at three Norwegian university hospitals. 130 preterm infants participated in the study, with 59 of them in the control group and 71 in the intervention group. Fidgety movements and overall movement character at three months corrected age. No difference was found between the intervention group and the control group in terms of fidgety movements or movement character. Approximately half of the infants in both groups showed an abnormal movement character. No evidence was found in this RCT to suggest that an intervention at 34 to 37weeks gestational age has a significant effect on the fidgety movements or overall movement character of preterm infants. This is in line with the assumption that absent fidgety movements and an abnormal movement character are due to permanent brain injury and are therefore good predictors for later neurological impairments. Copyright © 2017 Elsevier B.V. All rights reserved.

Ethnic discrimination and Latino depression: The mediating role of traumatic stress symptoms and alcohol use.

PubMed

Torres, Lucas; Vallejo, Leticia G

2015-10-01

Previous research has established a link between ethnic discrimination and poor mental health, yet the process by which this relationship occurs remains unclear. It has been hypothesized that the potential mechanisms accounting for the negative consequences of ethnic discrimination may be through stress responses and health behaviors (Pascoe & Smart Richman, 2009). The present study sought to examine the role of traumatic stress symptoms and alcohol use in mediating the relationship between ethnic discrimination and depressive symptoms. Two aspects of ethnic discrimination were assessed, namely source of discrimination and reaction to discrimination. The sample for the current study included 244 adult Latinos averaging approximately 40 years of age (SD = 15.29; range 18-85). Participants, which were comprised of mainly women (66%, n = 156), completed a series of paper-and-pencil questionnaires. Multiple mediator analyses revealed that, among U.S.-born but not foreign-born Latinos, both source of discrimination and reaction to discrimination were related to increased traumatic stress symptoms, which, in turn, was associated with depressive symptomatology. The traumatic stress symptoms pathway showed a robust indirect effect while alcohol use was not a statistically significant mediator. These major findings suggest that, while ethnic discrimination has a direct effect on depression, increased traumatic stress can account for this relationship particularly for U.S.-born Latinos. The findings are discussed within a stress and coping framework. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Current and Future Repellent Technologies: The Potential of Spatial Repellents and Their Place in Mosquito-Borne Disease Control.

PubMed

Norris, Edmund J; Coats, Joel R

2017-01-29

Every year, approximately 700,000 people die from complications associated with etiologic disease agents transmitted by mosquitoes. While insecticide-based vector control strategies are important for the management of mosquito-borne diseases, insecticide-resistance and other logistical hurdles may lower the efficacy of this approach, especially in developing countries. Repellent technologies represent another fundamental aspect of preventing mosquito-borne disease transmission. Among these technologies, spatial repellents are promising alternatives to the currently utilized contact repellents and may significantly aid in the prevention of mosquito-borne disease if properly incorporated into integrated pest management approaches. As their deployment would not rely on prohibitively expensive or impractical novel accessory technologies and resources, they have potential utility in developing countries where the burden of mosquito-borne disease is most prevalent. This review aims to describe the history of various repellent technologies, highlight the potential of repellent technologies in preventing the spread of mosquito-borne disease, and discuss currently known mechanisms that confer resistance to current contact and spatial repellents, which may lead to the failures of these repellents. In the subsequent section, current and future research projects aimed at exploring long-lasting non-pyrethroid spatial repellent molecules along with new paradigms and rationale for their development will be discussed.

Current and Future Repellent Technologies: The Potential of Spatial Repellents and Their Place in Mosquito-Borne Disease Control

PubMed Central

Norris, Edmund J.; Coats, Joel R.

2017-01-01

Every year, approximately 700,000 people die from complications associated with etiologic disease agents transmitted by mosquitoes. While insecticide-based vector control strategies are important for the management of mosquito-borne diseases, insecticide-resistance and other logistical hurdles may lower the efficacy of this approach, especially in developing countries. Repellent technologies represent another fundamental aspect of preventing mosquito-borne disease transmission. Among these technologies, spatial repellents are promising alternatives to the currently utilized contact repellents and may significantly aid in the prevention of mosquito-borne disease if properly incorporated into integrated pest management approaches. As their deployment would not rely on prohibitively expensive or impractical novel accessory technologies and resources, they have potential utility in developing countries where the burden of mosquito-borne disease is most prevalent. This review aims to describe the history of various repellent technologies, highlight the potential of repellent technologies in preventing the spread of mosquito-borne disease, and discuss currently known mechanisms that confer resistance to current contact and spatial repellents, which may lead to the failures of these repellents. In the subsequent section, current and future research projects aimed at exploring long-lasting non-pyrethroid spatial repellent molecules along with new paradigms and rationale for their development will be discussed. PMID:28146066

Quantifying Fusion Born Ion Populations in Magnetically Confined Plasmas using Ion Cyclotron Emission

DOE PAGES

Carbajal, L.; Warwick Univ., Coventry; Dendy, R. O.; ...

2017-03-07

Ion cyclotron emission (ICE) offers unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity P ICE scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, n /n i , of fusion-born alpha-particles confined within the plasma. We present fully nonlinear self-consistent kinetic simulations that reproduce this scaling for the first time. This resolves a longstanding question in the physics of fusion alpha particle confinement and stability in MCF plasmas. It confirms the MCI as the likely emissionmore » mechanism and greatly strengthens the basis for diagnostic exploitation of ICE in future burning plasmas.« less

Quantifying Fusion Born Ion Populations in Magnetically Confined Plasmas using Ion Cyclotron Emission

NASA Astrophysics Data System (ADS)

Carbajal, L.; Dendy, R. O.; Chapman, S. C.; Cook, J. W. S.

2017-03-01

Ion cyclotron emission (ICE) offers a unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity PICE scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, nα/ni, of fusion born alpha particles confined within the plasma. We present fully nonlinear self-consistent kinetic simulations that reproduce this scaling for the first time. This resolves a long-standing question in the physics of fusion alpha-particle confinement and stability in magnetic confinement fusion plasmas. It confirms the magnetoacoustic cyclotron instability as the likely emission mechanism and greatly strengthens the basis for diagnostic exploitation of ICE in future burning plasmas.

Quantifying Fusion Born Ion Populations in Magnetically Confined Plasmas using Ion Cyclotron Emission.

PubMed

Carbajal, L; Dendy, R O; Chapman, S C; Cook, J W S

2017-03-10

Ion cyclotron emission (ICE) offers a unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity P_{ICE} scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, n_{α}/n_{i}, of fusion born alpha particles confined within the plasma. We present fully nonlinear self-consistent kinetic simulations that reproduce this scaling for the first time. This resolves a long-standing question in the physics of fusion alpha-particle confinement and stability in magnetic confinement fusion plasmas. It confirms the magnetoacoustic cyclotron instability as the likely emission mechanism and greatly strengthens the basis for diagnostic exploitation of ICE in future burning plasmas.

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 .

Conformational energy landscape of the acyl pocket loop in acetylcholinesterase: a Monte Carlo-generalized Born model study.

PubMed

Carlacci, Louis; Millard, Charles B; Olson, Mark A

2004-10-01

The X-ray crystal structure of the reaction product of acetylcholinesterase (AChE) with the inhibitor diisopropylphosphorofluoridate (DFP) showed significant structural displacement in a loop segment of residues 287-290. To understand this conformational selection, a Monte Carlo (MC) simulation study was performed of the energy landscape for the loop segment. A computational strategy was applied by using a combined simulated annealing and room temperature Metropolis sampling approach with solvent polarization modeled by a generalized Born (GB) approximation. Results from thermal annealing reveal a landscape topology of broader basin opening and greater distribution of energies for the displaced loop conformation, while the ensemble average of conformations at 298 K favored a shift in populations toward the native by a free-energy difference in good agreement with the estimated experimental value. Residue motions along a reaction profile of loop conformational reorganization are proposed where Arg-289 is critical in determining electrostatic effects of solvent interaction versus Coulombic charging.

VLF Trimpi modelling on the path NWC-Dunedin using both finite element and 3D Born modelling

NASA Astrophysics Data System (ADS)

Nunn, D.; Hayakawa, K. B. M.

1998-10-01

This paper investigates the numerical modelling of VLF Trimpis, produced by a D region inhomogeneity on the great circle path. Two different codes are used to model Trimpis on the path NWC-Dunedin. The first is a 2D Finite Element Method Code (FEM), whose solutions are rigorous and valid in the strong scattering or non-Born limit. The second code is a 3D model that invokes the Born approximation. The predicted Trimpis from these codes compare very closely, thus confirming the validity of both models. The modal scattering matrices for both codes are analysed in some detail and are found to have a comparable structure. They indicate strong scattering between the dominant TM modes. Analysis of the scattering matrix from the FEM code shows that departure from linear Born behaviour occurs when the inhomogeneity has a horizontal scale size of about 100 km and a maximum electron density enhancement at 75 km altitude of about 6 electrons.

Asymptotic form for the cross section for the Coulomb interacting rearrangement collisions

NASA Technical Reports Server (NTRS)

Omidvar, K.

1973-01-01

It is shown that in a rearrangement collision leading to the formation of the highly excited hydrogenlike states the cross section in all orders of the Born approximation behaves as 1/n sq, with n the principal quantum number, thus invalidating the Brinkman-Kramers approximation for large n. Similarly, in high energy inelastic electron-hydrogenlike atom collisions the exchange cross section for sufficiently large n dominates the direct excitation cross section.

One-stage tooth-borne distraction versus two stage bone-borne distraction in surgically assisted maxillary expansion (SARME).

PubMed

Seeberger, Robin; Abe-Nickler, Dorothee; Hoffmann, Jürgen; Kunzmann, Kevin; Zingler, Sebastian

2015-12-01

To evaluate and compare the effects of tooth-borne and bone-borne distraction devices in surgically assisted maxillary expansion (SARME) on dental and skeletal structures. A sample of 33 skeletally mature patients with transverse maxillary deficiencies was examined with cone beam computed tomography (CBCT) before and 3 months after surgery. Fourteen patients were treated with tooth-borne devices and 19 patients with bone-borne devices. Dental crown expansion in the first premolars did not differ significantly between the two groups, and median expansion was 5.55 mm (interquartile range [IQR] 5.23) in the tooth-borne device group and 4.6 mm (IQR 3.4) in the bone-borne device group. In the first molars, crown expansion and lateral tipping were significantly greater in the tooth-borne device group (P ≤ .02). The median skeletal nasal isthmus increase was significantly more in the bone-borne device group at 3.0 mm than in the tooth-borne device group at 0.98 mm (P ≤ .02). Both tooth-borne and bone-borne devices are effective treatment modalities to correct maxillary transverse deficiencies. Bone-borne devices produced greater widening of the skeletal nasal floor and fewer dental side effects in the first molars. Copyright © 2015 Elsevier Inc. All rights reserved.

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.

Blackbody emission from light interacting with an effective moving dispersive medium.

PubMed

Petev, M; Westerberg, N; Moss, D; Rubino, E; Rimoldi, C; Cacciatori, S L; Belgiorno, F; Faccio, D

2013-07-26

Intense laser pulses excite a nonlinear polarization response that may create an effective flowing medium and, under appropriate conditions, a blocking horizon for light. Here, we analyze in detail the interaction of light with such laser-induced flowing media, fully accounting for the medium dispersion properties. An analytical model based on a first Born approximation is found to be in excellent agreement with numerical simulations based on Maxwell's equations and shows that when a blocking horizon is formed, the stimulated medium scatters light with a blackbody emission spectrum. Based on these results, diamond is proposed as a promising candidate medium for future studies of Hawking emission from artificial, dispersive horizons.

Functional neural bases of numerosity judgments in healthy adults born preterm.

PubMed

Clark, Caron A C; Liu, Yating; Wright, Nicolas Lee Abbot; Bedrick, Alan; Edgin, Jamie O

2017-11-01

High rates of mathematics learning disabilities among individuals born preterm (<37weeksGA) have spurred calls for a greater understanding of the nature of these weaknesses and their neural underpinnings. Groups of healthy, high functioning young adults born preterm and full term (n=20) completed a symbolic and non-symbolic magnitude comparison task while undergoing functional MRI scanning. Collectively, participants showed activation in superior and inferior frontal and parietal regions previously linked to numeric processing when comparing non-symbolic magnitude arrays separated by small numeric distances. Simultaneous deactivation of the default mode network also was evident during these trials. Individuals born preterm showed increased signal change relative to their full term peers in right inferior frontal and parietal regions when comparing the non-symbolic magnitude arrays. Elevated signal change during non-symbolic task blocks was associated with poorer performance on a calculation task administered outside of the scanner. These findings indicate that healthy, high-functioning adults born preterm may recruit fronto-parietal networks more extensively when processing non-symbolic magnitudes, suggesting that approximate number system training may be an inroad for early intervention to prevent mathematics difficulties in this population. Copyright © 2017 Elsevier Inc. All rights reserved.

Race differences in infant mortality from endogenous causes: a population-based study in North Carolina.

PubMed

Michielutte, R; Moore, M L; Meis, P J; Ernest, J M; Wells, H B

1994-02-01

This study examines the associations between race, birth weight, and mortality from endogenous causes for all singleton births born in 1984-1987 in a 20-county region of North Carolina. A more detailed analysis of preterm low birth weight infants examines these associations according to the proximate medical causes (medical etiology) of the preterm birth. Overall, black infants were found to have approximately twice the mortality risk of white infants. Most of the excess black mortality risk is explained by the larger proportion of black infants born at lower birth weights. The pattern of race differences in infant mortality by birth weight generally replicates the results of earlier studies, but the relative risk ratios within specific birth weight categories are smaller than previously reported. Among preterm low birth weight infants, the association between race and endogenous mortality differs within categories of medical etiology. The mortality risk is the same for black and white infants born preterm due to premature rupture of the membranes (PROM), lower for black infants born preterm due to medical problems, and higher for black infants born preterm due to idiopathic premature labor (IPL).

Variation in Differential and Total Cross Sections Due to Different Radial Wave Functions

ERIC Educational Resources Information Center

Williamson, W., Jr.; Greene, T.

1976-01-01

Three sets of analytical wave functions are used to calculate the Na (3s---3p) transition differential and total electron excitation cross sections by Born approximations. Results show expected large variations in values. (Author/CP)

Born approximation, multiple scattering, and butterfly algorithm

NASA Astrophysics Data System (ADS)

Martinez, Alex; Qiao, Zhijun

2014-06-01

Many imaging algorithms have been designed assuming the absence of multiple scattering. In the 2013 SPIE proceeding, we discussed an algorithm for removing high order scattering components from collected data. In this paper, our goal is to continue this work. First, we survey the current state of multiple scattering in SAR. Then, we revise our method and test it. Given an estimate of our target reflectivity, we compute the multi scattering effects in our target region for various frequencies. Furthermore, we propagate this energy through free space towards our antenna, and remove it from the collected data.

Susceptibility to Ticks and Lyme Disease Spirochetes Is Not Affected in Mice Coinfected with Nematodes.

PubMed

Maaz, Denny; Rausch, Sebastian; Richter, Dania; Krücken, Jürgen; Kühl, Anja A; Demeler, Janina; Blümke, Julia; Matuschka, Franz-Rainer; von Samson-Himmelstjerna, Georg; Hartmann, Susanne

2016-05-01

Small rodents serve as reservoir hosts for tick-borne pathogens, such as the spirochetes causing Lyme disease. Whether natural coinfections with other macroparasites alter the success of tick feeding, antitick immunity, and the host's reservoir competence for tick-borne pathogens remains to be determined. In a parasitological survey of wild mice in Berlin, Germany, approximately 40% of Ixodes ricinus-infested animals simultaneously harbored a nematode of the genus Heligmosomoides We therefore aimed to analyze the immunological impact of the nematode/tick coinfection as well as its effect on the tick-borne pathogen Borrelia afzelii Hosts experimentally coinfected with Heligmosomoides polygyrus and larval/nymphal I. ricinus ticks developed substantially stronger systemic type 2 T helper cell (Th2) responses, on the basis of the levels of GATA-3 and interleukin-13 expression, than mice infected with a single pathogen. During repeated larval infestations, however, anti-tick Th2 reactivity and an observed partial immunity to tick feeding were unaffected by concurrent nematode infections. Importantly, the strong systemic Th2 immune response in coinfected mice did not affect susceptibility to tick-borne B. afzelii An observed trend for decreased local and systemic Th1 reactivity against B. afzelii in coinfected mice did not result in a higher spirochete burden, nor did it facilitate bacterial dissemination or induce signs of immunopathology. Hence, this study indicates that strong systemic Th2 responses in nematode/tick-coinfected house mice do not affect the success of tick feeding and the control of the causative agent of Lyme disease. Copyright © 2016 Maaz et al.

An approximate inverse scattering technique for reconstructing blockage profiles in water pipelines using acoustic transients.

PubMed

Jing, Liwen; Li, Zhao; Wang, Wenjie; Dubey, Amartansh; Lee, Pedro; Meniconi, Silvia; Brunone, Bruno; Murch, Ross D

2018-05-01

An approximate inverse scattering technique is proposed for reconstructing cross-sectional area variation along water pipelines to deduce the size and position of blockages. The technique allows the reconstructed blockage profile to be written explicitly in terms of the measured acoustic reflectivity. It is based upon the Born approximation and provides good accuracy, low computational complexity, and insight into the reconstruction process. Numerical simulations and experimental results are provided for long pipelines with mild and severe blockages of different lengths. Good agreement is found between the inverse result and the actual pipe condition for mild blockages.

Accounting for Location Error in Kalman Filters: Integrating Animal Borne Sensor Data into Assimilation Schemes

PubMed Central

Sengupta, Aritra; Foster, Scott D.; Patterson, Toby A.; Bravington, Mark

2012-01-01

Data assimilation is a crucial aspect of modern oceanography. It allows the future forecasting and backward smoothing of ocean state from the noisy observations. Statistical methods are employed to perform these tasks and are often based on or related to the Kalman filter. Typically Kalman filters assumes that the locations associated with observations are known with certainty. This is reasonable for typical oceanographic measurement methods. Recently, however an alternative and abundant source of data comes from the deployment of ocean sensors on marine animals. This source of data has some attractive properties: unlike traditional oceanographic collection platforms, it is relatively cheap to collect, plentiful, has multiple scientific uses and users, and samples areas of the ocean that are often difficult of costly to sample. However, inherent uncertainty in the location of the observations is a barrier to full utilisation of animal-borne sensor data in data-assimilation schemes. In this article we examine this issue and suggest a simple approximation to explicitly incorporate the location uncertainty, while staying in the scope of Kalman-filter-like methods. The approximation stems from a Taylor-series approximation to elements of the updating equation. PMID:22900005

Few-body quark dynamics for doubly heavy baryons and tetraquarks

NASA Astrophysics Data System (ADS)

Richard, Jean-Marc; Valcarce, Alfredo; Vijande, Javier

2018-03-01

We discuss the adequate treatment of the three- and four-body dynamics for the quark model picture of double-charm baryons and tetraquarks. We stress that the variational and Born-Oppenheimer approximations give energies very close to the exact ones, while the diquark approximation might be somewhat misleading. The Hall-Post inequalities also provide very useful lower bounds that exclude the possibility of stable tetraquarks for some mass ratios and some color wave functions.

Balloon borne Antarctic frost point measurements and their impact on polar stratospheric cloud theories

NASA Technical Reports Server (NTRS)

Rosen, James M.; Hofmann, D. J.; Carpenter, J. R.; Harder, J. W.; Oltsmans, S. J.

1988-01-01

Balloon-borne frost point measurements were performed over Antarctica during September-October 1987 as part of the NOZE II effort at McMurdo. The results show water mixing ratios on the order of 2 ppmv in the 20 km region, suggesting that models of the springtime Antarctic stratosphere should be based on approximately 2 ppmv water vapor. Evidence indicating that some PSCs form at temperatures higher than the frost point in the 15 to 20 km region is discussed. This supports the binary HNO3-H2O theory of PSC composition.

Low birthweight among US Hispanic/Latino subgroups: the effect of maternal foreign-born status and education.

PubMed

Acevedo-Garcia, Dolores; Soobader, Mah-J; Berkman, Lisa F

2007-12-01

We investigated whether maternal foreign-born status confers a protective effect against low birthweight (LBW) across US Hispanic/Latino subgroups (i.e., Mexicans, Puerto Ricans, Cubans and Central/South Americans) in the USA, and whether the association between maternal education and LBW varies by Hispanic/Latino subgroup and by foreign-born status. We conducted logistic regression analyses of the 2002 US Natality Detail Data (n=634,797). Overall, foreign-born Latino women are less likely to have LBW infants than US-born Latino women. The protective effect of foreign-born status is stronger among Latino women with less than high school education. The maternal education gradient is significantly flatter among foreign-born Latino women than among their US-born counterparts (p<0.001). Patterns among Mexican-origin women account for the overall trends among all Latinos.Foreign-born status (main effect) reduces the risk of LBW among Mexicans by about 21% but does not protect against LBW among other Latino subgroups (i.e., Puerto Ricans, Cubans and Central/South Americans). Among Mexicans and Central South Americans, the protective effect of foreign-born status is stronger among women with low education (i.e., 0-11 and 12 years) than among women with more education (i.e., 13-15 and 16+ years). The educational gradient in LBW is less pronounced among foreign-born Mexicans and Central/South Americans than among their US-born counterparts. As such, maternal foreign-born status and education are associated with LBW, though the direction and strength of these associations vary across Latino subgroups. A "health paradox" is apparent for foreign-born Mexican and Central/South American women among whom there is a weak maternal educational gradient in LBW. Future research may test hypotheses regarding the mechanisms underlying these variations in LBW among Latino subgroups, i.e., different gradients in sending countries, health selection of immigrants, cultural factors, and social support.

Sharp peaks in the conductance of a double quantum dot and a quantum-dot spin valve at high temperatures: A hierarchical quantum master equation approach

NASA Astrophysics Data System (ADS)

Wenderoth, S.; Bätge, J.; Härtle, R.

2016-09-01

We study sharp peaks in the conductance-voltage characteristics of a double quantum dot and a quantum dot spin valve that are located around zero bias. The peaks share similarities with a Kondo peak but can be clearly distinguished, in particular as they occur at high temperatures. The underlying physical mechanism is a strong current suppression that is quenched in bias-voltage dependent ways by exchange interactions. Our theoretical results are based on the quantum master equation methodology, including the Born-Markov approximation and a numerically exact, hierarchical scheme, which we extend here to the spin-valve case. The comparison of exact and approximate results allows us to reveal the underlying physical mechanisms, the role of first-, second- and beyond-second-order processes and the robustness of the effect.

Charge-equilibrium and radiation of low-energy cosmic rays passing through interstellar medium

NASA Technical Reports Server (NTRS)

Rule, D. W.; Omidvar, K.

1977-01-01

The charge equilibrium and radiation of an oxygen and an iron beam in the MeV per nucleon energy range, representing a typical beam of low-energy cosmic rays passing through the interstellar medium, is considered. Electron loss of the beam has been taken into account by means of the First Born approximation allowing for the target atom to remain unexcited, or to be excited to all possible states. Electron capture cross sections have been calculated by means of the scaled Oppenheimer-Brinkman-Kramers approximation, taking into account all atomic shells of the target atoms. Radiation of the beam due to electron capture into the excited states of the ion, collisional excitation and collisional inner-shell ionization of the ions has been considered. Effective X-ray production cross sections and multiplicities for the most energetic X-ray lines emitted by the Fe and O beams have been calculated.

Disparities in vaccinations and cancer screening among U.S.- and foreign-born Arab and European American non-Hispanic White women.

PubMed

Dallo, Florence J; Kindratt, Tiffany B

2015-01-01

Disparities in vaccinations and cancer screening exist when comparing foreign-born and U.S.-born women collectively and disaggregated by race and ethnicity. The purpose of this study was to estimate and compare the age-adjusted prevalence of not receiving a flu or pneumonia vaccine, clinical breast examination, mammogram or Pap smear among U.S.- and foreign-born White women by region of birth and examine associations while controlling for potential confounders. We pooled 12 years of National Health Interview Survey data (n = 117,893). To approximate an "Arab-American" ethnicity, we identified 15 "Arab" countries from the Middle East region that comprise the Arab Nations. Data was requested from the National Center for Health Statistics Research Data Center. We used the χ(2) statistic to compare descriptive statistics and odds ratios (ORs) with 95% CIs were used for inferential statistics. Compared to U.S.-born, foreign-born Whites from the Arab Nations had higher estimates of not receiving recommended vaccinations and cancer screenings. In crude and adjusted analyses, foreign-born Arab-American women were less likely to report receiving a flu vaccine (OR, 0.34; 95% CI, 0.21-0.58), pneumonia vaccine (OR, 0.14; 95% CI, 0.06-0.32), Pap smear (OR, 0.13; 95% CI, 0.05-0.31), or clinical breast examination (OR, 0.16; 95% CI, 0.07-0.37) compared with U.S.-born White women. There were no differences for mammography. This national study examining uptake of flu and pneumonia vaccines and preventive cancer screenings suggests that estimates are lower for foreign-born Arab-American women compared with U.S.-born White women. Future studies should collect qualitative data that assess the cultural context surrounding prevention and screening behaviors among Arab-American women. Copyright © 2015 Jacobs Institute of Women's Health. Published by Elsevier Inc. All rights reserved.

Testicular cancer risk and maternal parity: a population-based cohort study.

PubMed

Westergaard, T; Andersen, P K; Pedersen, J B; Frisch, M; Olsen, J H; Melbye, M

1998-04-01

The aim was to study, in a population-based cohort design, whether first-born sons run a higher risk of testicular cancer than later born sons; to investigate whether this difference in risk was affected by birth cohort, age of the son, maternal age, interval to previous delivery and other reproductive factors; and, finally, to evaluate to what extent changes in women's parity over time might explain the increasing incidence of testicular cancer. By using data from the Civil Registration System, a database was established of all women born in Denmark since 1935 and all their children alive in 1968 or born later. Sons with testicular cancer were identified in the Danish Cancer Registry. Among 1015994 sons followed for 15981 967 person-years, 626 developed testicular cancer (443 non-seminomas, 183 seminomas). Later born sons had a decreased risk of testicular cancer (RR = 0.80, 95% CI = 0.67-0.95) compared with first-born sons. The RR was 0.79 (95% CI = 0.64-0.98) for non-seminomas and 0.81 (95% CI = 0.58-1.13) for seminomas. There was no association between testicular cancer risk and overall parity of the mother, maternal or paternal age at the birth of the son, or maternal age at first birth. The decreased risk of testicular cancer among later born sons was not modified by age, birth cohort, interval to the previous birth, sex of the first-born child, or maternal age at birth of the son or at first birth. The increased proportion of first-borns from birth cohort 1946 to birth cohort 1969 only explained around 3% of an approximated two-fold increase in incidence between the cohorts. Our data document a distinctly higher risk of testicular cancer in first-born compared with later born sons and suggest that the most likely explanation should be sought among exposures in utero. The increase in the proportion of first-borns in the population has only contributed marginally to the increase in testicular cancer incidence.

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.

Suburban migration and the birth outcome of Chicago-born white and African-American women: the merit of the healthy migrant theory?

PubMed

Collins, James W; Rankin, Kristin M; Janowiak, Christine M

2013-11-01

The healthy migrant theory posits that women who migrate before pregnancy are intrinsically healthier and therefore have better birth outcomes than those who don't move. Objective. To determine whether migration to the suburbs is associated with lower rates of preterm (<37 weeks) birth among Chicago-born White and African-American mothers. We performed stratified and multilevel logistic regression analyses on an Illinois transgenerational dataset of non-Latino White and African-American infants (1989-1991) and their mothers (1956-1976) with appended US census income information. Forty percent of Chicago-born White mothers (N = 45,135) migrated to Suburban Cook County and 30 % migrated to the more geographically distant collar counties. In contrast, 10 % of Chicago-born African-American mothers (N = 41,221) migrated to Suburban Cook and only two percent migrated to the collar counties. Chicago-born White and African-American migrant mothers to Suburban Cook County had lower preterm birth rates than their non-migrant counterparts; RR = 0.8 (0.8-0.9) and 0.8 (0.7-0.8), respectively. When neighborhood income was singularly taken into account, the protective association of suburban migration and preterm birth disappeared among Chicago-born Whites. In race-specific multilevel multivariate regression models which included neighborhood income, the adjusted odds ratio of preterm birth, low birth weight, and small for gestational-age for Chicago-born White and African-American migrant (compared to non-migrant) mothers approximated unity. Neighborhood income underlies the protective association of suburban migration and birth outcome among Chicago-born White and African-American mothers. These findings do not support the healthy migrant hypothesis of reproductive outcome.

Students' Moral Reasoning as Related to Cultural Background and Educational Experience.

ERIC Educational Resources Information Center

Bar-Yam, Miriam; And Others

The relationship between moral development and cultural and educational background is examined. Approximately 120 Israeli youth representing different social classes, sex, religious affiliation, and educational experience were interviewed. The youth interviewed included urban middle and lower class students, Kibbutz-born, Youth Aliyah…

Research notes : pavement markings using waterborne paint and Visibeads in Region 2.

DOT National Transportation Integrated Search

1995-01-01

In order to address the problems associated with solvent-borne patins, ODOT Region 2 staff bought sufficient waterborne paint to place approximately 760 linear miles of stripes. This enabled the Region staff to evaluate state-of-the-art materials and...

High-frequency Born synthetic seismograms based on coupled normal modes

USGS Publications Warehouse

Pollitz, F.

2011-01-01

High-frequency and full waveform synthetic seismograms on a 3-D laterally heterogeneous earth model are simulated using the theory of coupled normal modes. The set of coupled integral equations that describe the 3-D response are simplified into a set of uncoupled integral equations by using the Born approximation to calculate scattered wavefields and the pure-path approximation to modulate the phase of incident and scattered wavefields. This depends upon a decomposition of the aspherical structure into smooth and rough components. The uncoupled integral equations are discretized and solved in the frequency domain, and time domain results are obtained by inverse Fourier transform. Examples show the utility of the normal mode approach to synthesize the seismic wavefields resulting from interaction with a combination of rough and smooth structural heterogeneities. This approach is applied to an ~4 Hz shallow crustal wave propagation around the site of the San Andreas Fault Observatory at Depth (SAFOD). ?? The Author Geophysical Journal International ?? 2011 RAS.

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.

The sexual and reproductive health of foreign-born women in the United States.

PubMed

Tapales, Athena; Douglas-Hall, Ayana; Whitehead, Hannah

2018-02-14

To explore the sexual and reproductive health (SRH) behaviors, health insurance coverage and use of SRH services of women in the United States (U.S.) by nativity, disaggregated by race and ethnicity. We analyzed publicly available and restricted data from the National Survey of Family Growth to assess differences and similarities between foreign-born and U.S.-born women, both overall and within Hispanic, non-Hispanic (NH) white, NH black and NH Asian groups. A larger proportion of foreign-born women than U.S.-born women lacked health insurance coverage. Foreign-born women utilized SRH services at lower rates than U.S.-born women; this effect diminished at the multivariate level, although race and ethnicity differences remained. Overall, foreign-born women were less likely to pay for SRH services with private insurance than U.S.-born women. Foreign-born women were less likely to use the most effective contraceptive methods than U.S.-born women, with some variation across race and ethnicity: NH white and NH black foreign-born women were less likely to use highly effective contraceptive methods than their U.S.-born counterparts, but among Hispanic women, the reverse was true. Our findings demonstrate that the SRH behaviors, needs and outcomes of foreign-born women differ from those of U.S-born women within the same race/ethnic group. This paper contributes to the emergent literature on immigrants in the U.S. by laying the foundation for further research on the SRH of the foreign-born population in the country, which is critical for developing public health policies and programs to understand better and serve this growing and diverse population. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Disparity in disability between native-born non-Hispanic white and foreign-born Asian older adults in the United States: effects of educational attainment and age at immigration.

PubMed

Lee, Min-Ah

2011-04-01

It is widely known that educational attainment has considerable influence on the prevalence of disability among native-born non-Hispanic older adults in the US. However, few studies have examined whether educational attainment has a similar effect on disability among foreign-born Asian older adults. If it does not have a similar effect on these adults, why not, and is its effect influenced by the age at which they immigrated to the US? This study addresses these questions by using the 2006 American Community Survey Public Use Microdata Sample (ACS PUMS). Logistic regression analyses reveal that education has differential effects on the two racial groups. Education protects foreign-born Asians less than native-born non-Hispanic whites. In addition, Asian adults who immigrated earlier are less likely to experience disability. Interestingly, the interaction between age at immigration and educational attainment for foreign-born Asian older adults indicates that less educated Asians are more likely to benefit from early immigration. Heterogeneity within the Asian group is also examined. The findings suggest that educational attainment has differential effects not only on the two racial groups but also on the foreign-born Asian group depending on age at immigration. Copyright © 2011 Elsevier Ltd. All rights reserved.

General relativistic corrections to the weak lensing convergence power spectrum

NASA Astrophysics Data System (ADS)

Giblin, John T.; Mertens, James B.; Starkman, Glenn D.; Zentner, Andrew R.

2017-11-01

We compute the weak lensing convergence power spectrum, Cℓκκ, in a dust-filled universe using fully nonlinear general relativistic simulations. The spectrum is then compared to more standard, approximate calculations by computing the Bardeen (Newtonian) potentials in linearized gravity and partially utilizing the Born approximation. We find corrections to the angular power spectrum amplitude of order ten percent at very large angular scales, ℓ˜2 - 3 , and percent-level corrections at intermediate angular scales of ℓ˜20 - 30 .

Positronium formation in e+ plus H- collisions

NASA Technical Reports Server (NTRS)

Straton, Jack C.; Drachman, Richard J.

1990-01-01

Cross sections for positronium formation by capture from the negative hydrogen ion are given. Orthogonalization corrections to the Coulomb (First) Born Approximation (CBA) differential and total cross sections are calculated using approximate H- wave functions of both Lowdin and Chandrasekhar. Various methods of orthogonalizing the unbound projectile to the possible bound states are considered. It is found that treating the atomic nuclei as if they were isotopic spin projections of a single type of nucleon gives cross sections that are an improvement over the CBA.

Mixed effects versus fixed effects modelling of binary data with inter-subject variability.

PubMed

Murphy, Valda; Dunne, Adrian

2005-04-01

The question of whether or not a mixed effects model is required when modelling binary data with inter-subject variability and within subject correlation was reported in this journal by Yano et al. (J. Pharmacokin. Pharmacodyn. 28:389-412 [2001]). That report used simulation experiments to demonstrate that, under certain circumstances, the use of a fixed effects model produced more accurate estimates of the fixed effect parameters than those produced by a mixed effects model. The Laplace approximation to the likelihood was used when fitting the mixed effects model. This paper repeats one of those simulation experiments, with two binary observations recorded for every subject, and uses both the Laplace and the adaptive Gaussian quadrature approximations to the likelihood when fitting the mixed effects model. The results show that the estimates produced using the Laplace approximation include a small number of extreme outliers. This was not the case when using the adaptive Gaussian quadrature approximation. Further examination of these outliers shows that they arise in situations in which the Laplace approximation seriously overestimates the likelihood in an extreme region of the parameter space. It is also demonstrated that when the number of observations per subject is increased from two to three, the estimates based on the Laplace approximation no longer include any extreme outliers. The root mean squared error is a combination of the bias and the variability of the estimates. Increasing the sample size is known to reduce the variability of an estimator with a consequent reduction in its root mean squared error. The estimates based on the fixed effects model are inherently biased and this bias acts as a lower bound for the root mean squared error of these estimates. Consequently, it might be expected that for data sets with a greater number of subjects the estimates based on the mixed effects model would be more accurate than those based on the fixed effects model. This is borne out by the results of a further simulation experiment with an increased number of subjects in each set of data. The difference in the interpretation of the parameters of the fixed and mixed effects models is discussed. It is demonstrated that the mixed effects model and parameter estimates can be used to estimate the parameters of the fixed effects model but not vice versa.

Extrauterine growth restriction was associated with short stature and thinness in very low birth weight infants at around six years of age.

PubMed

Takayanagi, Toshimitsu; Shichijo, Akinori; Egashira, Masakazu; Egashira, Tomoko; Mizukami, Tomoko

2018-06-04

The effect that intrauterine or extrauterine growth restriction (EUGR) had on the build of very low birth weight (VLBW) infants was investigated before Japanese children started school. Between 2005 and 2017 the National Hospital Organization, Saga, Japan, carried out pre-school checks on 322 children born with a VLBW at approximately six years of age. Growth restriction was defined as being born small for gestational age (SGA) or EUGR if they were born at term. The prevalence of short stature, thinness and obesity were determined and associations between SGA or EUGR and subsequent body build were investigated. In this study, 77/322 (23.9%) infants were SGA and 153/322 (47.5%) were EUGR: 14/77 (18.2%) SGA infants caught up in growth to the 169 non EUGR infants, while 90/245 (36.7%) appropriate for gestational age infants subsequently demonstrated EUGR. There were 38 (11.8%) short stature, 38 (11.8%) thin and six (1.9%) obese subjects in the total cohort and growth hormone deficiencies in nine (2.8%) cases. We found significant associations between EUGR and both short stature and thinness. EUGR was significantly associated with short stature and thinness in VLBW infants at around six years, irrespective of the degree of SGA. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Performance of Djallonké sheep under an extensive system of production in Faranah, Guinea.

PubMed

Mourad, M; Gbanamou, G; Balde, I B

2001-10-01

A total of 147 ewes, 4 rams and 188 lambs of their progeny of the Djallonké breed of sheep were used to study the factors affecting reproductive and growth traits and the causes of lamb mortality. Data on ewes were collected during a 12-month period, while those on the lambs born to 123 of the ewes were collected until they were 12 months of age. The average fertility and abortion rates were 0.84 and 0.09. The fertility rate increased and the abortion rate decreased with increasing age of the ewes (p<0.05). The number of lambs born per ewe joined, litter weight at birth per ewe joined and litter weight at weaning per ewe joined were 1.28, 3.5 kg and 17 kg, respectively. The average numbers of lambs born per ewe, lambs born alive per ewe, lambs born dead per ewe and lambs per ewe that died between birth and weaning were 1.53, 1.43, 0.03 and 0.3, respectively. The age of the ewes significantly (p<0.05) affected all these traits except the number of dead lambs and the index of fertility (94%). The age of the ewes significantly (p<0.05) affected the birth weight and the weight at 6 and 12 months of age, whereas the lambing season significantly (p<0.05) affected all the growth traits studied. The type of birth was the most important source of variation in body weights of lambs. Sex had no significant (p>0.05) effect on the growth traits studied. The complex 'starvation-bad management-light body weight at birth' caused 48% of the lamb mortality between birth and weaning, while diarrhoea, pneumonia and internal and external parasites caused approximately 52% of the lamb mortality over the same period. The seasonal raw mortality rate of the lambs before weaning was highest in the humid season.

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.

Growth hormone therapy for children born small for gestational age: height gain is less dose dependent over the long term than over the short term.

PubMed

de Zegher, Francis; Hokken-Koelega, Anita

2005-04-01

Approximately 3% of children are born small for gestational age (SGA), and approximately 10% of SGA children maintain a small body size throughout childhood and often into adult life. Among short SGA children, growth hormone (GH) therapy increases short-term growth in a dose-dependent manner; experience with long-term therapy is limited. To delineate the dose dependency of long-term height gain among short SGA children receiving GH therapy. We performed an epianalysis of the first adult height data for SGA children (n = 28) enrolled in 3 randomized trials comparing the growth-promoting efficacy of 2 continuous GH regimens (33 or 67 microg/kg per day for approximately 10 years, starting at approximately 5 years of age); in addition, we performed a meta-analysis of the adult height results published previously and those presented here. Epianalysis outcomes (n = 28) suggested that adult height increased more with a higher-dose regimen than with a lower-dose regimen. In the meta-analysis (n = 82), the higher-dose regimen was found to elicit a long-term height gain superior to that achieved with the lower-dose regimen by a mean of 0.4 SD (approximately 1 inch). Children who were shorter at the start of therapy experienced more long-term height gain. These findings confirm GH therapy as an effective and safe approach to reduce the adult height deficit that short SGA children otherwise face. In addition, the first meta-analysis indicated that height gain is less dose dependent over the long term than over the short term, at least within the dose range explored to date. For SGA children whose stature is not extremely short, current data support the use of a GH dose of approximately 33 microg/kg per day from start to adult height, particularly if treatment starts at a young age; shorter children (for example, height below -3 SD) might benefit from an approach in which short-term catch-up growth is achieved with a higher dose (> or =50 microg/kg per day) and long-term growth to adult height is ensured with a GH dose of approximately 33 mug/kg per day. Because GH-induced accelerations of height and weight gain evolve in parallel, the dose tapering from > or =50 microg/kg to approximately 33 microg/kg can be accomplished by simply maintaining the absolute GH dose (in micrograms) while the child gains weight (in kilograms). With this algorithm, more growth-responsive children taper their GH dose down to approximately 33 microg/kg per day more quickly.

The fading American dream: Trends in absolute income mobility since 1940.

PubMed

Chetty, Raj; Grusky, David; Hell, Maximilian; Hendren, Nathaniel; Manduca, Robert; Narang, Jimmy

2017-04-28

We estimated rates of "absolute income mobility"-the fraction of children who earn more than their parents-by combining data from U.S. Census and Current Population Survey cross sections with panel data from de-identified tax records. We found that rates of absolute mobility have fallen from approximately 90% for children born in 1940 to 50% for children born in the 1980s. Increasing Gross Domestic Product (GDP) growth rates alone cannot restore absolute mobility to the rates experienced by children born in the 1940s. However, distributing current GDP growth more equally across income groups as in the 1940 birth cohort would reverse more than 70% of the decline in mobility. These results imply that reviving the "American dream" of high rates of absolute mobility would require economic growth that is shared more broadly across the income distribution. Copyright © 2017, American Association for the Advancement of Science.

Diagonal Born-Oppenheimer correction for coupled-cluster wave-functions

NASA Astrophysics Data System (ADS)

Shamasundar, K. R.

2018-06-01

We examine how geometry-dependent normalisation freedom of electronic wave-functions affects extraction of a meaningful diagonal Born-Oppenheimer correction (DBOC) to the ground-state Born-Oppenheimer potential energy surface (PES). By viewing this freedom as a kind of gauge-freedom, it is shown that DBOC and the resulting associated mass-dependent adiabatic PES are gauge-invariant quantities. A sum-over-states (SOS) formula for DBOC which explicitly exhibits this invariance is derived. A biorthogonal formulation suitable for DBOC computations using standard unnormalised coupled-cluster (CC) wave-functions is presented. This is shown to lead to a biorthogonal version of SOS formula with similar properties. On this basis, different computational schemes for evaluating DBOC using approximate CC wave-functions are derived. One of this agrees with the formula used in the current literature. The connection to adiabatic-to-diabatic transformations in non-adiabatic dynamics is explored and complications arising from biorthogonal nature of CC theory are identified.

A multiplex serologic platform for diagnosis of tick-borne diseases.

PubMed

Tokarz, Rafal; Mishra, Nischay; Tagliafierro, Teresa; Sameroff, Stephen; Caciula, Adrian; Chauhan, Lokendrasingh; Patel, Jigar; Sullivan, Eric; Gucwa, Azad; Fallon, Brian; Golightly, Marc; Molins, Claudia; Schriefer, Martin; Marques, Adriana; Briese, Thomas; Lipkin, W Ian

2018-02-16

Tick-borne diseases are the most common vector-borne diseases in the United States, with serology being the primary method of diagnosis. We developed the first multiplex, array-based assay for serodiagnosis of tick-borne diseases called the TBD-Serochip. The TBD-Serochip was designed to discriminate antibody responses to 8 major tick-borne pathogens present in the United States, including Anaplasma phagocytophilum, Babesia microti, Borrelia burgdorferi, Borrelia miyamotoi, Ehrlichia chaffeensis, Rickettsia rickettsii, Heartland virus and Powassan virus. Each assay contains approximately 170,000 12-mer linear peptides that tile along the protein sequence of the major antigens from each agent with 11 amino acid overlap. This permits accurate identification of a wide range of specific immunodominant IgG and IgM epitopes that can then be used to enhance diagnostic accuracy and integrate differential diagnosis into a single assay. To test the performance of the TBD-Serochip, we examined sera from patients with confirmed Lyme disease, babesiosis, anaplasmosis, and Powassan virus disease. We identified a wide range of specific discriminatory epitopes that facilitated accurate diagnosis of each disease. We also identified previously undiagnosed infections. Our results indicate that the TBD-Serochip is a promising tool for a differential diagnosis not available with currently employed serologic assays for TBDs.

Electrical excitability: a spectrum of properties in the progeny of a single embryonic neuroblast.

PubMed Central

Goodman, C S; Pearson, K G; Spitzer, N C

1980-01-01

We have examined the range of some properties of the progeny of a single embryonic precursor cell in the grasshopper. The approximately 100 progeny of this single neuroblast share certain features such as their transmitter and some aspects of their morphology; at the same time, however, they demonstrate a broad spectrum of electrical properties, from spiking to non-spiking neurons. The first-born progeny are spiking neurons with peripheral axons. Many of the progeny, including all of the last-born, do not generate action potentials. The nonspiking progeny are local intraganglionic neurons and appear to compose a major proportion of the progeny of this neuroblast. All of the nonspiking neurons have calcium inward current channels and can make action potentials when outward current channels are blocked. We propose a model for grasshopper neurogenesis based on cell lineage such that (i) certain features (e.g., transmitter) are shared by the progeny of all cell divisions from a single neuroblast, and (ii) other features (e.g., electrical properties) are shared by the progeny of a given birth position (e.g., first versus last born) from all of the neuroblasts. According to this model, the first-born progeny from all neuroblasts are spiking neurons, whereas the last-born are nonspiking. Images PMID:6246499

Explicit inclusion of nonlocality in ( d , p ) transfer reactions

DOE PAGES

Titus, L. J.; Nunes, F. M.; Potel, G.

2016-01-06

Traditionally, nucleon-nucleus optical potentials are made local for convenience. In recent work we studied the effects of including nonlocal interactions explicitly in the final state for (d,p) reactions, within the distorted wave Born approximation. Our goal in this work is to develop an improved formalism for nonlocal interactions that includes deuteron breakup and to use it to study the effects of including nonlocal interactions in transfer (d,p) reactions, in both the deuteron and the proton channel. We extend the finite-range adiabatic distorted wave approximation to include nonlocal nucleon optical potentials. We apply our method to (d,p) reactions on 16O, 40Ca,more » 48Ca, 126Sn, 132Sn, and 208Pb at 10, 20 and 50 MeV. Here, we find that nonlocality in the deuteron scattering state reduces the amplitude of the wave function in the nuclear interior, and shifts the wave function outward. In many cases, this has the effect of increasing the transfer cross section at the first peak of the angular distributions. This increase was most significant for heavy targets and for reactions at high energies. Lastly, our systematic study shows that, if only local optical potentials are used in the analysis of experimental (d, p) transfer cross sections, the extracted spectroscopic factors may be incorrect by up to 40% due to the local approximation.« less

The Effects of Climate Change and Globalization on Mosquito Vectors: Evidence from Jeju Island, South Korea on the Potential for Asian Tiger Mosquito (Aedes albopictus) Influxes and Survival from Vietnam Rather Than Japan

PubMed Central

Jeong, Ji Yeon; Yoo, Seung Jin; Koh, Young-Sang; Lee, Seogjae; Heo, Sang Taek; Seong, Seung-Yong; Lee, Keun Hwa

2013-01-01

Background Climate change affects the survival and transmission of arthropod vectors as well as the development rates of vector-borne pathogens. Increased international travel is also an important factor in the spread of vector-borne diseases (VBDs) such as dengue, West Nile, yellow fever, chikungunya, and malaria. Dengue is the most important vector-borne viral disease. An estimated 2.5 billion people are at risk of infection in the world and there are approximately 50 million dengue infections and an estimated 500,000 individuals are hospitalized with dengue haemorrhagic fever annually. The Asian tiger mosquito (Aedes albopictus) is one of the vectors of dengue virus, and populations already exist on Jeju Island, South Korea. Currently, colder winter temperatures kill off Asian tiger mosquito populations and there is no evidence of the mosquitos being vectors for the dengue virus in this location. However, dengue virus-bearing mosquito vectors can inflow to Jeju Island from endemic area such as Vietnam by increased international travel, and this mosquito vector's survival during colder winter months will likely occur due to the effects of climate change. Methods and Results In this section, we show the geographical distribution of medically important mosquito vectors such as Ae. albopictus, a vector of both dengue and chikungunya viruses; Culex pipiens, a vector of West Nile virus; and Anopheles sinensis, a vector of Plasmodium vivax, within Jeju Island, South Korea. We found a significant association between the mean temperature, amount of precipitation, and density of mosquitoes. The phylogenetic analyses show that an Ae. albopictus, collected in southern area of Jeju Island, was identical to specimens found in Ho Chi Minh, Vietnam, and not Nagasaki, Japan. Conclusion Our results suggest that mosquito vectors or virus-bearing vectors can transmit from epidemic regions of Southeast Asia to Jeju Island and can survive during colder winter months. Therefore, Jeju Island is no longer safe from vector borne diseases (VBDs) due to the effects of globalization and climate change, and we should immediately monitor regional climate change to identify newly emerging VBDs. PMID:23894312

The effects of climate change and globalization on mosquito vectors: evidence from Jeju Island, South Korea on the potential for Asian tiger mosquito (Aedes albopictus) influxes and survival from Vietnam rather than Japan.

PubMed

Lee, Su Hyun; Nam, Kwang Woo; Jeong, Ji Yeon; Yoo, Seung Jin; Koh, Young-Sang; Lee, Seogjae; Heo, Sang Taek; Seong, Seung-Yong; Lee, Keun Hwa

2013-01-01

Climate change affects the survival and transmission of arthropod vectors as well as the development rates of vector-borne pathogens. Increased international travel is also an important factor in the spread of vector-borne diseases (VBDs) such as dengue, West Nile, yellow fever, chikungunya, and malaria. Dengue is the most important vector-borne viral disease. An estimated 2.5 billion people are at risk of infection in the world and there are approximately 50 million dengue infections and an estimated 500,000 individuals are hospitalized with dengue haemorrhagic fever annually. The Asian tiger mosquito (Aedes albopictus) is one of the vectors of dengue virus, and populations already exist on Jeju Island, South Korea. Currently, colder winter temperatures kill off Asian tiger mosquito populations and there is no evidence of the mosquitos being vectors for the dengue virus in this location. However, dengue virus-bearing mosquito vectors can inflow to Jeju Island from endemic area such as Vietnam by increased international travel, and this mosquito vector's survival during colder winter months will likely occur due to the effects of climate change. In this section, we show the geographical distribution of medically important mosquito vectors such as Ae. albopictus, a vector of both dengue and chikungunya viruses; Culex pipiens, a vector of West Nile virus; and Anopheles sinensis, a vector of Plasmodium vivax, within Jeju Island, South Korea. We found a significant association between the mean temperature, amount of precipitation, and density of mosquitoes. The phylogenetic analyses show that an Ae. albopictus, collected in southern area of Jeju Island, was identical to specimens found in Ho Chi Minh, Vietnam, and not Nagasaki, Japan. Our results suggest that mosquito vectors or virus-bearing vectors can transmit from epidemic regions of Southeast Asia to Jeju Island and can survive during colder winter months. Therefore, Jeju Island is no longer safe from vector borne diseases (VBDs) due to the effects of globalization and climate change, and we should immediately monitor regional climate change to identify newly emerging VBDs.

Microwave backscattering from an anisotropic soybean canopy

NASA Technical Reports Server (NTRS)

Lang, R. H.; Saatchi, S.; Levine, D. M.

1986-01-01

Electromagnetic backscattering from a soybean canopy is modeled in the L band region of the spectrum. Mature soybean plants are taken as an ensemble of leaves and stems which are represented by lossy dielectric disks and rods respectively. Field data indicated that leaves and stems are not distributed uniformly in the azimuth coordinate. The plant has a tendency to grow out into the area between the rows. The effects on backscattered radar waves was computed by the distorted Born approximation. Results for look directions along the rows and perpendicular to the rows show that only a modest difference occurs in the L band frequency range. The use of another nonuniform distribution, different from those observed experimentally, results in a significant effect due to vegetation asymmetry.

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.

Young adult outcomes of children born to teen mothers: effects of being born during their teen or later years.

PubMed

Lipman, Ellen L; Georgiades, Katholiki; Boyle, Michael H

2011-03-01

Children of teen mothers exhibit adverse outcomes through adolescence. It is unclear whether these adverse outcomes extend to adulthood and apply to all of her children, or only those born when she was a teen. We examine the associations between young adult functioning and being born to a teen mother aged ≤20 years at the time of birth (current teen), and being born to a teen mother later in her life (>21 years, prior teen). The 1983 Ontario Child Health Study (OCHS) and 2001 follow-up are used, including 2,355 participants 4 to 16 years old in 1983 with 2001 data. Using multilevel modeling we assessed the association between being born to a current versus prior teen mother, relative to a nonteen mother, and 2001 outcomes, controlling for individual and family level characteristics assessed in childhood. Being born to a teen mother (versus a nonteen mother) is associated with poorer educational achievement, life satisfaction, and personal income. Accounting for time of sample children's birth in teen mothers' lives, individuals born to current and prior teen mothers showed a ~0.8-year educational deficit, relative to individuals born to nonteen mothers in fully adjusted models. Individuals born to current teen mothers reported lower life satisfaction and personal income (-$7,262). There were no significant group differences at follow-up in mental or physical health between individuals born to nonteen mothers and those born to current or prior teen mothers. Although being born to a teen mother exerts a pervasive adverse effect on educational attainment, the adverse effects on life satisfaction and personal income appear to be selective for individuals born to a current teen mother. Further research is required to understand these differential effects. Copyright © 2011 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

Predictability of tick-borne encephalitis fluctuations.

PubMed

Zeman, P

2017-10-01

Tick-borne encephalitis is a serious arboviral infection with unstable dynamics and profound inter-annual fluctuations in case numbers. A dependable predictive model has been sought since the discovery of the disease. The present study demonstrates that four superimposed cycles, approximately 2·4, 3, 5·4, and 10·4 years long, can account for three-fifths of the variation in the disease fluctuations over central Europe. Using harmonic regression, these cycles can be projected into the future, yielding forecasts of sufficient accuracy for up to 4 years ahead. For the years 2016-2018, this model predicts elevated incidence levels in most parts of the region.

Full-Genome Characterisation of Orungo, Lebombo and Changuinola Viruses Provides Evidence for Co-Evolution of Orbiviruses with Their Arthropod Vectors

PubMed Central

Mohd Jaafar, Fauziah; Belhouchet, Mourad; Belaganahalli, Manjunatha; Tesh, Robert B.; Mertens, Peter P. C.; Attoui, Houssam

2014-01-01

The complete genomes of Orungo virus (ORUV), Lebombo virus (LEBV) and Changuinola virus (CGLV) were sequenced, confirming that they each encode 11 distinct proteins (VP1-VP7 and NS1-NS4). Phylogenetic analyses of cell-attachment protein ‘outer-capsid protein 1′ (OC1), show that orbiviruses fall into three large groups, identified as: VP2(OC1), in which OC1 is the 2nd largest protein, including the Culicoides transmitted orbiviruses; VP3(OC1), which includes the mosquito transmitted orbiviruses; and VP4(OC1) which includes the tick transmitted viruses. Differences in the size of OC1 between these groups, places the T2 ‘subcore-shell protein’ as the third largest protein ‘VP3(T2)’ in the first of these groups, but the second largest protein ‘VP3(T2)’ in the other two groups. ORUV, LEBV and CGLV all group with the Culicoides-borne VP2(OC1)/VP3(T2) viruses. The G+C content of the ORUV, LEBV and CGLV genomes is also similar to that of the Culicoides-borne, rather than the mosquito-borne, or tick borne orbiviruses. These data suggest that ORUV and LEBV are Culicoides- rather than mosquito-borne. Multiple isolations of CGLV from sand flies suggest that they are its primary vector. OC1 of the insect-borne orbiviruses is approximately twice the size of the equivalent protein of the tick borne viruses. Together with internal sequence similarities, this suggests its origin by duplication (concatermerisation) of a smaller OC1 from an ancestral tick-borne orbivirus. Phylogenetic comparisons showing linear relationships between the dates of evolutionary-separation of their vector species, and genetic-distances between tick-, mosquito- or Culicoides-borne virus-groups, provide evidence for co-evolution of the orbiviruses with their arthropod vectors. PMID:24475112

Healthy(?), wealthy, and wise: Birth order and adult health.

PubMed

Black, Sandra E; Devereux, Paul J; Salvanes, Kjell G

2016-12-01

While recent research has found that birth order affects outcomes such as education and earnings, the evidence for effects on health is more limited. This paper uses a large Norwegian dataset to focus on the relationship between birth order and a range of health and health-related behaviors, outcomes not previously available in datasets of this magnitude. Interestingly, we find complicated effects of birth order. First-borns are more likely to be overweight, to be obese, and to have high blood pressure and high triglycerides. For example, compared to fifth-borns, first-borns are about 5% points more likely to be obese and 7% points more likely to have high blood pressure. So, unlike education or earnings, there is no clear first-born advantage in health. However, first-borns are about 13% points less likely to smoke daily than fifth-borns and are more likely to report good physical and mental health. Later-borns also score lower on well-being with fifth-borns being about 9% points less likely than first-borns to report that they are happy. Our findings are generally monotonic with middle-borns having outcomes that are intermediate between first- and fifth-borns. We find that these effects are largely unaffected by conditioning on education and earnings, suggesting that these are not the only important pathways to health differentials by birth order. When we explore possible mechanisms, we find that early maternal investment may play a role in birth order effects on health. Copyright © 2016 Elsevier B.V. All rights reserved.

Racial/ethnic disparities in obesity among US-born and foreign-born adults by sex and education.

PubMed

Barrington, Debbie S; Baquero, Maria C; Borrell, Luisa N; Crawford, Natalie D

2010-02-01

This study examines sex and education variations in obesity among US- and foreign-born whites, blacks, and Hispanics utilizing 1997-2005 data from the National Health Interview Survey on 267,585 adults aged > or =18 years. After adjusting for various demographic, health, and socioeconomic factors via logistic regression, foreign-born black men had the lowest odds for obesity relative to US-born white men. The largest racial/ethnic disparity in obesity was between US-born black and white women. High educational attainment diminished the US-born black-white and Hispanic-white disparities among women, increased these disparities among men, and had minimal effect on foreign-born Hispanic-white disparities among women and men. Comprehension of these relationships is vital for conducting effective obesity research and interventions within an increasingly diverse United States.

Climate change and vector-borne diseases of public health significance.

PubMed

Ogden, Nicholas H

2017-10-16

There has been much debate as to whether or not climate change will have, or has had, any significant effect on risk from vector-borne diseases. The debate on the former has focused on the degree to which occurrence and levels of risk of vector-borne diseases are determined by climate-dependent or independent factors, while the debate on the latter has focused on whether changes in disease incidence are due to climate at all, and/or are attributable to recent climate change. Here I review possible effects of climate change on vector-borne diseases, methods used to predict these effects and the evidence to date of changes in vector-borne disease risks that can be attributed to recent climate change. Predictions have both over- and underestimated the effects of climate change. Mostly under-estimations of effects are due to a focus only on direct effects of climate on disease ecology while more distal effects on society's capacity to control and prevent vector-borne disease are ignored. There is increasing evidence for possible impacts of recent climate change on some vector-borne diseases but for the most part, observed data series are too short (or non-existent), and impacts of climate-independent factors too great, to confidently attribute changing risk to climate change. © Crown copyright 2017.

Infant born preterm have delayed development of adaptive postural control in the first 5 months of life.

PubMed

Dusing, Stacey C; Thacker, Leroy R; Galloway, James C

2016-08-01

Infants born preterm are at increased risk of developmental disabilities, that may be attributed to their early experiences and ability to learn. The purpose of this paper was to evaluate the ability of infants born preterm to adapt their postural control to changing task demands. This study included 18 infants born at 32 weeks of gestation or less whose posture was compared in supine under 2 conditions, with and without a visual stimulus presented. The postural variability, measured with root mean squared displacement of the center of pressure, and postural complexity, measured with the approximate entropy of the center of pressure displacement were measured longitudinally from 2.5 to 5 months of age. The infants looked at the toys in midline for several months prior to adapting their postural variability in a manner similar to full term infants. Only after postural variability was reduced in both the caudal cephalic and medial lateral direction in the toy condition did the infants learn to reach for the toy. Postural complexity did not vary between conditions. These findings suggest that infants used a variety of strategies to control their posture. In contrast to research with infants born full term, the infants born preterm in this study did not identify the successful strategy of reducing movement of the center of pressure until months after showing interest in the toy. This delayed adaptation may impact the infants ability to learn over time. Copyright © 2016 Elsevier Inc. All rights reserved.

Genetic analysis of litter size, parturition length, and birth assistance requirements in primiparous sows using a joint linear-threshold animal model.

PubMed

Holm, B; Bakken, M; Vangen, O; Rekaya, R

2004-09-01

The aim of this study was to investigate whether selection for number of live born piglets has led to prolonged parturition and increased requirement for birth assistance, resulting in increased numbers of stillborn piglets. Data were collected from 6,718 primiparous Norwegian Landrace sows farrowing between 2001 and 2003. The need for birth assistance was recorded as a binary response. Physical intervention in the birth of piglets and/or hormonal treatment by the farmer was recorded as birth assistance. The duration of the parturition was analyzed as a binary trait (<4 h and >4 h). The statistical model used for analysis included contemporary groups of herd-year, litter breed, season of farrowing, parity in which the sow was born, a regression on the age of sow at farrowing, an additive genetic effect, and a service sire effect. A full Bayesian approach via Gibbs sampling was adopted to estimate the genetic relationships between these four traits. A total chain length of 100,000 iterations was run. The first 10,000 samples were discarded as burn-in, and the remaining 90,000 iterations were retained without thinning for post-Gibbs analysis. The highest direct heritability was estimated for the number of live-born piglets (h2 = 0.07), followed by the duration of farrowing (h2 = 0.05), the need for birth assistance (h2 = 0.05), and the number of stillborn piglets (h2 = 0.04). The genetic correlations revealed that the number of live and stillborn piglets was uncorrelated; however, the number of live piglets born had a moderate genetic correlation to the need for birth assistance (rg = 0.24 +/- 0.01) and duration of farrowing (rg = -0.20 +/- 0.01), whereas the number of stillborn piglets was highly correlated to the need for birth assistance (rg = 0.74 +/- 0.01) and the duration of parturition (rg = 0.66 +/- 0.01). The duration of farrowing and the need for birth assistance were genetically highly correlated (rg = 0.89 +/- 0.00). For all traits, the service sire variance was approximately one quarter in magnitude compared with its respective genetic variance. The results showed that selection for the number of live born piglets is not expected to influence the number of stillborn piglets. Increasing the number of live piglets born through selection should have a slight negative effect on farrowing duration and a minor increase in the need for birth assistance. Sows with a high genetic potential for birth assistance and prolonged parturition were more likely to give birth to greater numbers of stillborn piglets.

Electron-ion collision rates in noble gas clusters irradiated by femtosecond laser pulse

NASA Astrophysics Data System (ADS)

Dey, R.; Roy, A. C.

2012-05-01

We report a theoretical analysis of electron-ion collision rates in xenon gas clusters irradiated by femtosecond laser pulses. The present analysis is based on the eikonal approximation (EA), the first Born approximation (FBA) and the classical (CL) methods. The calculations are performed using the plasma-screened Rogers potential introduced by Moll et al. [J. Phys. B. 43, 135103 (2010)] as well as the Debye potential for a wide range of experimental parameters. We find that the magnitudes of electron-ion collision frequency obtained in the EA do not fall as rapidly with the kinetic energy of electrons as in the FBA and CL methods for higher charge states of xenon ion (Xe8+ and Xe14+). Furthermore, EA shows that the effect of the inner structure of ion is most dominant for the lowest charge state of xenon ion (Xe1+). In the case of the present effective potential, FBA overestimates the CL results for all three different charge states of xenon, whereas for the Debye potential, both the FBA and CL methods predict collision frequencies which are nearly close to each other.

Polarized optical scattering by inhomogeneities and surface roughness in an anisotropic thin film

DOE PAGES

Germer, Thomas A.; Sharma, Katelynn A.; Brown, Thomas G.; ...

2017-10-18

We extend the theory for scattering by oblique columnar structure thin films to include the induced form birefringence and the propagation of radiation in those films. We generalize the 4 × 4 matrix theory to include arbitrary sources in the layer, which are necessary to determine the Green function for the inhomogeneous wave equation. We further extend first-order vector perturbation theory for scattering by roughness in the smooth surface limit, when the layer is anisotropic. Scattering by an inhomogeneous medium is approximated by a distorted Born approximation, where effective medium theory is used to determine the effective properties of themore » medium and strong fluctuation theory is used to determine the inhomogeneous sources. In this manner, we develop a model for scattering by inhomogeneous films, with anisotropic correlation functions. Here, the results are compared to Mueller matrix bidirectional scattering distribution function measurements for a glancing-angle deposition (GLAD) film. While the results are applied to the GLAD film example, the development of the theory is general enough that it can guide simulations for scattering in other anisotropic thin films.« less

Decoherence and lead-induced interdot coupling in nonequilibrium electron transport through interacting quantum dots: A hierarchical quantum master equation approach

NASA Astrophysics Data System (ADS)

Härtle, R.; Cohen, G.; Reichman, D. R.; Millis, A. J.

2013-12-01

The interplay between interference effects and electron-electron interactions in electron transport through an interacting double quantum dot system is investigated using a hierarchical quantum master equation approach which becomes exact if carried to infinite order and converges well if the temperature is not too low. Decoherence due to electron-electron interactions is found to give rise to pronounced negative differential resistance, enhanced broadening of structures in current-voltage characteristics, and an inversion of the electronic population. Dependence on gate voltage is shown to be a useful method of distinguishing decoherence-induced phenomena from effects induced by other mechanisms such as the presence of a blocking state. Comparison of results obtained by the hierarchical quantum master equation approach to those obtained from the Born-Markov approximation to the Nakajima-Zwanzig equation and from the noncrossing approximation to the nonequilibrium Green's function reveals the importance of an interdot coupling that originates from the energy dependence of the conduction bands in the leads and the need for a systematic perturbative expansion.

Helping Young Hispanic Learners

ERIC Educational Resources Information Center

Garcia, Eugene E.; Jensen, Bryant

2007-01-01

Hispanics are the largest and youngest ethnic group in the United States. Moreover, young Hispanic children make up approximately 80 percent of the U.S. English language learner population. They are a heterogeneous group, born both inside and outside the United States and having origins in Mexico, Cuba, Central America, South America, and the…

Johanna and Tommy: Two Preschoolers in Sweden with Brittle Bones.

ERIC Educational Resources Information Center

Millde, Kristina; Brodin, Jane

Information is presented for caregivers of Swedish children with osteogenesis imperfecta (brittle bones) and their families. Approximately five children with brittle bones are born in Sweden annually. Two main types of brittle bone disease have been identified: congenita and tarda. Typical symptoms include numerous and unexpected fractures, bluish…

Earth Observation

NASA Image and Video Library

2014-05-31

ISS040-E-006165 (31 May 2014 ) --- One of the Expedition 40 crew members aboard the International Space Station photographed this nadir image of the volcanic-born Banks Peninsula, on the east coast of the South Island of New Zealand on May 31, 2014. Banks Peninsula covers an area of approximately 1,150 square kilometers.

Combined active and passive microwave remote sensing of vegetated surfaces at l-band

USDA-ARS?s Scientific Manuscript database

In previous work the distorted Born approximation (DBA) of volume scattering was combined with the numerical solutions of Maxwell equations (NMM3D) for a rough surface to calculate the radar backscattering coefficient for the Soil Moisture Active Passive (SMAP) mission. The model results were valida...

Leucine is a major regulator of muscle protein synthesis in neonates

USDA-ARS?s Scientific Manuscript database

Approximately 10 % of infants born in the United States are of low birth weight. Growth failure during the neonatal period is a common occurrence in low birth weight infants due to their inability to tolerate full feeds, concerns about advancing protein supply, and high nutrient requirements for gro...

Efficacy and effectiveness of infant vaccination against chronic hepatitis B in the Gambia Hepatitis Intervention Study (1986-90) and in the nationwide immunisation program.

PubMed

Peto, Thomas J; Mendy, Maimuma E; Lowe, Yamundow; Webb, Emily L; Whittle, Hilton C; Hall, Andrew J

2014-01-07

Gambian infants were not routinely vaccinated against hepatitis B virus (HBV) before 1986. During 1986-90 the Gambia Hepatitis Intervention Study (GHIS) allocated 125,000 infants, by area, to vaccination or not and thereafter all infants were offered the vaccine through the nationwide immunisation programme. We report HBV serology from samples of GHIS vaccinees and unvaccinated controls, and from children born later. During 2007-08, 2670 young adults born during the GHIS (1986-90) were recruited from 80 randomly selected villages and four townships. Only 28% (753/2670) could be definitively linked to their infant HBV vaccination records (255 fully vaccinated, 23 partially vaccinated [1-2 doses], 475 not vaccinated). All were tested for current HBV infection (HBV surface antigen [HBsAg]) and, if HBsAg-negative, evidence of past infection (HBV core-protein antibody [anti-HBc]). HBsAg-positive samples (each with two age- and sex-matched HBsAg-negative samples) underwent liver function tests. In addition, 4613 children born since nationwide vaccination (in 1990-2007) were tested for HBsAg. Statistical analyses ignore clustering. Comparing fully vaccinated vs unvaccinated GHIS participants, current HBV infection was 0.8% (2/255) vs 12.4% (59/475), p < 0.0001, suggesting 94% (95% CI 77-99%) vaccine efficacy. Among unvaccinated individuals, the prevalence was higher in males (p = 0.015) and in rural areas (p = 0.009), but adjustment for this did not affect estimated vaccine efficacy. Comparing fully vaccinated vs unvaccinated participants, anti-HBc was 27.4% (70/255) vs 56.0% (267/475), p < 0.00001. Chronic active hepatitis was not common: the proportion of HBsAg-positive subjects with abnormal liver function tests (ALT > 2 ULN) was 4.1%, compared with 0.2% in those HBsAg-negative. The prevalence of antibodies to hepatitis C virus was low (0.5%, 13/2592). In children born after the end of GHIS, HBsAg prevalence has remained low; 1.4% (15/1103) in those born between 1990-97, and 0.3% (9/35150) in those born between 1998-2007. Infant HBV vaccination achieves substantial protection against chronic carriage in early adulthood, even though approximately a quarter of vaccinated young adults have been infected. This protection persists past the potential onset of sexual activity, reinforcing previous GHIS findings of protection during childhood and suggesting no need for a booster dose. Nationwide infant HBV vaccination is controlling chronic infection remarkably effectively.

Joint Effects of Age, Period, and Cohort on Conduct Problems Among American Adolescents From 1991 Through 2015.

PubMed

Keyes, Katherine M; Gary, Dahsan S; Beardslee, Jordan; Prins, Seth J; O'Malley, Patrick M; Rutherford, Caroline; Schulenberg, John

2018-03-01

Although arrest rates among juveniles have substantially decreased since the 1990s, US national trends in conduct problems are unknown. Population variation in conduct problems would imply changes in the social environment, which would include emergent or receding risk factors. In the present study, we separated age, period, and cohort effects on conduct problems using nationally representative surveys of 375,879 US students conducted annually (1991-2015). The summed score of 7 items measuring the frequency of conduct problems was the outcome. Conduct problems have decreased during the past 25 years among boys; the total amount of the decrease was approximately 0.4 standard deviations (P < 0.01), and by item prevalence, the total amount of the decrease was 8%-11%. Declines are best explained by period effects beginning approximately in 2008, and a declining cohort effect beginning among those born after 1992, which suggests not only declines in population levels, but more rapid declines among younger cohorts of boys. Trends were also consistent with age-period-cohort effects on evenings spent out, which suggest a possible mechanism. Conduct problems among girls were lower than boys and did not demonstrate trends across time. These changes may reflect the changing nature of adolescence toward less unsupervised interaction.

Immigration and lifetime prevalence of DSM-IV psychiatric disorders among Mexican Americans and non-Hispanic whites in the United States: results from the National Epidemiologic Survey on Alcohol and Related Conditions.

PubMed

Grant, Bridget F; Stinson, Frederick S; Hasin, Deborah S; Dawson, Deborah A; Chou, S Patricia; Anderson, Karyn

2004-12-01

There exist no national prevalence data on specific DSM-IV Axis I psychiatric disorders among foreign-born and US-born Mexican Americans and non-Hispanic whites. To present nationally representative data on the prevalence of DSM-IV lifetime psychiatric disorders among foreign-born and US-born Mexican Americans and non-Hispanic whites. Face-to-face survey conducted in the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions. The United States and District of Columbia, including Alaska and Hawaii. Household and group-quarters residents, aged 18 years and older (n = 43 093). Prevalence of DSM-IV substance use disorders and mood and anxiety disorders. With few exceptions, foreign-born Mexican Americans and foreign-born non-Hispanic whites were at significantly lower risk (P<.05) of DSM-IV substance use and mood and anxiety disorders compared with their US-born counterparts. Although the risk of specific psychiatric disorders was similar between foreign-born Mexican Americans and foreign-born non-Hispanic whites, US-born Mexican Americans were at significantly lower risk (P<.05) of psychiatric morbidity than US-born non-Hispanic whites. Data favoring foreign-born Mexican Americans with respect to mental health may extend to foreign-born non-Hispanic whites. Future research among foreign-born and US-born Mexican Americans and the foreign-born and US-born of other origins and descents is needed to understand what appears to be the protective effects of culture and the deleterious effects of acculturation on psychiatric morbidity in the United States.

Maternal Drug Use during Pregnancy: Are Preterm and Full-Term Infants Affected Differently?

ERIC Educational Resources Information Center

Brown, Josephine V.; Bakeman, Roger; Coles, Claire D.; Sexson, William R.; Demi, Alice S.

1998-01-01

Examined effects of prenatal drug exposure on infants born preterm and full-term to African American mothers. Found more extreme fetal growth deficits in later-born infants, and more extreme irritability increases in earlier-born infants. Gestation length did not moderate cardiorespiratory reactivity effects. Exposure effects occurred for…

Towards the quantization of Eddington-inspired-Born-Infeld theory

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

Bouhmadi-López, Mariam; Chen, Che-Yu, E-mail: mbl@ubi.pt, E-mail: b97202056@gmail.com

2016-11-01

The quantum effects close to the classical big rip singularity within the Eddington-inspired-Born-Infeld theory (EiBI) are investigated through quantum geometrodynamics. It is the first time that this approach is applied to a modified theory constructed upon Palatini formalism. The Wheeler-DeWitt (WDW) equation is obtained and solved based on an alternative action proposed in ref. [1], under two different factor ordering choices. This action is dynamically equivalent to the original EiBI action while it is free of square root of the spacetime curvature. We consider a homogeneous, isotropic and spatially flat universe, which is assumed to be dominated by a phantommore » perfect fluid whose equation of state is a constant. We obtain exact solutions of the WDW equation based on some specific conditions. In more general cases, we propose a qualitative argument with the help of a Wentzel-Kramers-Brillouin (WKB) approximation to get further solutions. Besides, we also construct an effective WDW equation by simply promoting the classical Friedmann equations. We find that for all the approaches considered, the DeWitt condition hinting singularity avoidance is satisfied. Therefore the big rip singularity is expected to be avoided through the quantum approach within the EiBI theory.« less

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.

Rotational-vibrational coupling in the theory of electron-molecule scattering

NASA Technical Reports Server (NTRS)

Temkin, A.; Sullivan, E. C.

1974-01-01

The adiabatic-nuclei approximation of vibrational-rotational excitation of homonuclear diatomic molecules can be simply augmented to describe the vibrational-rotational coupling by including the dependence of the vibrational wave function on j. Appropriate formulas are given, and the theory, is applied to e-H2 excitation, whereby it is shown that deviations from the simple Born-Oppenheimer approximation measured by Wong and Schultz can be explained. More important, it can be seen that the inclusion of the j-dependent centrifugal term is essential for transitions involving high-rotational quantum numbers.

School absence and its effect on school performance for children born with orofacial clefts.

PubMed

Bell, Jane; Raynes-Greenow, Camille; Turner, Robin; Bower, Carol; Dodson, Alan; Hancock, Kirsten; Nassar, Natasha

2017-07-17

School absence is associated with lower performance on standardized tests. Children born with orofacial clefts (OFC) are likely to have more absence than children without OFC; however, school absence for children with OFC has not been quantified. We aimed to describe school absence and its relationship with school performance for children with and without OFC. Population-based record-linked cohort study of children (402 with OFC, 1789 without OFC) enrolled in schools in Western Australia, 2008 to 2012. We compared median school absence rates using Wilcoxon rank tests, and investigated the impact of school absence on standardized scores from reading, numeracy, and writing tests, using multivariable models fitted by generalized estimating equations. In Semester 1, at each primary school year level, children without OFC and children with cleft lip only or cleft palate only had similar median absence rates (approximately 1 week). Children with cleft lip and palate had significantly higher absence rates in Years 4 to 6 (between 1 and 2 weeks). During secondary school, median absence rates were higher (2 weeks) for all children, but not statistically different between children with and without OFC. Higher absence was significantly associated with lower standardized reading, numeracy, and writing scores. However, having a cleft of any type had little influence on the association between absence and test scores. School absence affected school performance for all children. Absence did not differentially disadvantage children born with OFC, suggesting current practices to identify and support children with OFC are minimizing effects of their absence on school performance. Birth Defects Research 109:1048-1056, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

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

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.

Performance of different theories for the angular distribution of bremsstrahlung produced by keV electrons incident upon a target

NASA Astrophysics Data System (ADS)

Omar, Artur; Andreo, Pedro; Poludniowski, Gavin

2018-07-01

Different theories of the intrinsic bremsstrahlung angular distribution (i.e., the shape function) have been evaluated using Monte Carlo calculations for various target materials and incident electron energies between 20 keV and 300 keV. The shape functions considered were the plane-wave first Born approximation cross sections (i) 2BS [high-energy result, screened nucleus], (ii) 2BN [general result, bare nucleus], (iii) KM [2BS modified to emulate 2BN], and (iv) SIM [leading term of 2BN]; (v) expression based on partial-waves expansion, KQP; and (vi) a uniform spherical distribution, UNI [a common approximation in certain analytical models]. The shape function was found to have an important impact on the bremsstrahlung emerging from thin foil targets in which the incident electrons undergo few elastic scatterings before exiting the target material. For thick transmission and reflection targets the type of shape function had less importance, as the intrinsic bremsstrahlung angular distribution was masked by the diffuse directional distribution of multiple scattered electrons. Predictions made using the 2BN and KQP theories were generally in good agreement, suggesting that the effect of screening and the constraints of the Born approximation on the intrinsic angular distribution may be acceptable. The KM and SIM shape functions deviated notably from KQP for low electron energies (< 50 keV), while 2BS and UNI performed poorly over most of the energy range considered; the 2BS shape function was found to be too forward-focused in emission, while UNI was not forward-focused enough. The results obtained emphasize the importance of the intrinsic bremsstrahlung angular distribution for theoretical predictions of x-ray emission, which is relevant in various applied disciplines, including x-ray crystallography, electron-probe microanalysis, security and industrial inspection, medical imaging, as well as low- and medium (orthovoltage) energy radiotherapy.

Mosquito-borne viruses circulating in Kinshasa, Democratic Republic of the Congo.

PubMed

Mbanzulu, Kennedy Makola; Wumba, Roger; Mukendi, Jean-Pierre Kambala; Zanga, Josué Kikana; Shija, Fortunate; Bobanga, Thierry Lengu; Aloni, Michel Ntetani; Misinzo, Gerald

2017-04-01

Diseases caused by mosquito-borne viruses are among the most important emerging diseases that threaten human and animal health, particularly in Africa. However, little attention has been paid to these diseases in the Democratic Republic of the Congo (DRC). The present cross-sectional study was undertaken between March and May 2014 to investigate the presence of mosquito-borne viruses in mosquitoes collected from five municipalities of Kinshasa, DRC. Mosquitoes were collected using BG-Sentinel traps and battery-powered aspirators. Female mosquitoes were pooled according to their genera and sampling locations, preserved in RNAlater, and later screened for viruses using reverse transcription PCR (RT-PCR) assays. A total of 2922 mosquitoes were collected and 29 pools of female mosquitoes, containing approximately 30 mosquitoes each, were tested. Twelve of the 29 (41.4%) mosquito pools were found to be infected with at least one arbovirus, with eight (27.5%) pools positive for Alphavirus, nine (31%) for Flavivirus, and five (17.2%) for Bunyaviridae. Chikungunya, o'nyong'nyong, and Rift valley fever viruses were detected. The present study shows that mosquitoes in Kinshasa carry mosquito-borne viruses that may have serious public health implications. Further investigations on the presence of mosquito-borne viruses in the human and livestock populations of Kinshasa and DRC are recommended. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

The influence of cross-order terms in interface mobilities for structure-borne sound source characterization

NASA Astrophysics Data System (ADS)

Bonhoff, H. A.; Petersson, B. A. T.

2010-08-01

For the characterization of structure-borne sound sources with multi-point or continuous interfaces, substantial simplifications and physical insight can be obtained by incorporating the concept of interface mobilities. The applicability of interface mobilities, however, relies upon the admissibility of neglecting the so-called cross-order terms. Hence, the objective of the present paper is to clarify the importance and significance of cross-order terms for the characterization of vibrational sources. From previous studies, four conditions have been identified for which the cross-order terms can become more influential. Such are non-circular interface geometries, structures with distinctively differing transfer paths as well as a suppression of the zero-order motion and cases where the contact forces are either in phase or out of phase. In a theoretical study, the former four conditions are investigated regarding the frequency range and magnitude of a possible strengthening of the cross-order terms. For an experimental analysis, two source-receiver installations are selected, suitably designed to obtain strong cross-order terms. The transmitted power and the source descriptors are predicted by the approximations of the interface mobility approach and compared with the complete calculations. Neglecting the cross-order terms can result in large misinterpretations at certain frequencies. On average, however, the cross-order terms are found to be insignificant and can be neglected with good approximation. The general applicability of interface mobilities for structure-borne sound source characterization and the description of the transmission process thereby is confirmed.

Pleural mesothelioma and lung cancer risks in relation to occupational history and asbestos lung burden

PubMed Central

Gilham, Clare; Rake, Christine; Burdett, Garry; Nicholson, Andrew G; Davison, Leslie; Franchini, Angelo; Carpenter, James; Hodgson, John; Darnton, Andrew; Peto, Julian

2016-01-01

Background We have conducted a population-based study of pleural mesothelioma patients with occupational histories and measured asbestos lung burdens in occupationally exposed workers and in the general population. The relationship between lung burden and risk, particularly at environmental exposure levels, will enable future mesothelioma rates in people born after 1965 who never installed asbestos to be predicted from their asbestos lung burdens. Methods Following personal interview asbestos fibres longer than 5 µm were counted by transmission electron microscopy in lung samples obtained from 133 patients with mesothelioma and 262 patients with lung cancer. ORs for mesothelioma were converted to lifetime risks. Results Lifetime mesothelioma risk is approximately 0.02% per 1000 amphibole fibres per gram of dry lung tissue over a more than 100-fold range, from 1 to 4 in the most heavily exposed building workers to less than 1 in 500 in most of the population. The asbestos fibres counted were amosite (75%), crocidolite (18%), other amphiboles (5%) and chrysotile (2%). Conclusions The approximate linearity of the dose–response together with lung burden measurements in younger people will provide reasonably reliable predictions of future mesothelioma rates in those born since 1965 whose risks cannot yet be seen in national rates. Burdens in those born more recently will indicate the continuing occupational and environmental hazards under current asbestos control regulations. Our results confirm the major contribution of amosite to UK mesothelioma incidence and the substantial contribution of non-occupational exposure, particularly in women. PMID:26715106

Plasma-screening effects on the electron-impact excitation of hydrogenic ions in dense plasmas

NASA Technical Reports Server (NTRS)

Jung, Young-Dae

1993-01-01

Plasma-screening effects are investigated on electron-impact excitation of hydrogenic ions in dense plasmas. Scaled cross sections Z(exp 4) sigma for 1s yields 2s and 1s yields 2p are obtained for a Debye-Hueckel model of the screened Coulomb interaction. Ground and excited bound wave functions are modified in the screened Coulomb potential (Debye-Hueckel model) using the Ritz variation method. The resulting atomic wave functions and their eigenenergies agree well with the numerical and high-order perturbation theory calculations for the interesting domain of the Debye length not less than 10. The Born approximation is used to describe the continuum states of the projectile electron. Plasma screening effects on the atomic electrons cannot be neglected in the high-density cases. Including these effects, the cross sections are appreciably increased for 1s yields 2s transitions and decreased for 1s yields 2p transitions.

Emissivity of half-space random media. [in passive remote sensing

NASA Technical Reports Server (NTRS)

Tsang, L.; Kong, J. A.

1976-01-01

Scattering of electromagnetic waves by a half-space random medium with three-dimensional correlation functions is studied with the Born approximation. The emissivity is calculated from a simple integral and is illustrated for various cases. The results are valid over a wavelength range smaller or larger than the correlation lengths.

Handle with Care

ERIC Educational Resources Information Center

Merrill, Margaret C.

2006-01-01

The Centers for Disease Control estimates that every year 76 million Americans get some kind of food poisoning, more than 300,000 are hospitalized, and approximately 5,000 people die. A 2004 analysis by the Center for Science in the Public Interest indicates that contaminated produce is responsible for the greatest number of food-borne illnesses.…

Transitioning Young Adults with Autism: Hopes & Challenges for Parents

ERIC Educational Resources Information Center

Mookerjee, Veera

2012-01-01

Data generated by the Center for Disease Control (CDC) from the 2010 census indicates that out of four million children born in the United States "approximately 36,500 children will eventually be diagnosed with an [Autism Spectrum Disorder] ASD" ("http://www.cdc.gov/ncbddd/autism/data.html"). The process of caring for an…

A Cartoon in One Dimension of the Hydrogen Molecular Ion

ERIC Educational Resources Information Center

Dutta, Sourav; Ganguly, Shreemoyee; Dutta-Roy, Binayak

2008-01-01

To illustrate the basic methodology involved in the quantum mechanics of molecules, a one-dimensional caricature of the hydrogen molecular ion (H[superscript +][subscript 2]) is presented, which is exactly solvable, in the Born-Oppenheimer approximation, in terms of elementary functions. The purpose of the exercise is to elucidate in a simple…

Dietary Patterns and Intelligence in Early and Middle Childhood

ERIC Educational Resources Information Center

Theodore, Reremoana F.; Thompson, John M. D.; Waldie, Karen E.; Wall, Clare; Becroft, David M. O.; Robinson, Elizabeth; Wild, Chris J.; Clark, Philippa M.; Mitchell, Ed A.

2009-01-01

The association between intelligence and diet at 3.5 and 7 years was examined in 591 children of European descent. Approximately half of the children were born small-for-gestational age (birth weight @?10th percentile). The relationship between IQ and diet (measured by food frequency) was investigated using multiple regression analyses. Eating…

Magnetic Resonance Imaging--Insights into Brain Injury and Outcomes in Premature Infants

ERIC Educational Resources Information Center

Mathur, Amit; Inder, Terrie

2009-01-01

Preterm birth is a major public-health issue because of its increasing incidence combined with the frequent occurrence of subsequent behavioral, neurological, and psychiatric challenges faced by surviving infants. Approximately 10-15% of very preterm children (born less than 30 weeks gestational age) develop cerebral palsy, and 30-60% of them…

Lessons in Learning: More Education, Less Employment--Immigrants and the Labour Market

ERIC Educational Resources Information Center

Canadian Council on Learning, 2008

2008-01-01

Nearly one out of five Canadian residents was born outside of Canada and approximately two-thirds of Canada's population growth results from net international migration. Only Australia, where immigrants represent 24% of the population, has a greater percentage of immigrants than Canada (18%). Immigration is a major factor in Canada's economic…

Microbial profiling, neural network and semantic web: an integrated information system for human pathogen risk management, prevention and surveillance in food safety

USDA-ARS?s Scientific Manuscript database

It is estimated that food-borne pathogens cause approximately 76 million cases of gastrointestinal illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States annually. Genomic, proteomic, and metabolomic studies, particularly, genome sequencing projects are providing valuable inform...

Sodium Chloride Supplementation Is Not Routinely Performed in the Majority of German and Austrian Infants with Classic Salt-Wasting Congenital Adrenal Hyperplasia and Has No Effect on Linear Growth and Hydrocortisone or Fludrocortisone Dose.

PubMed

Bonfig, Walter; Roehl, Friedhelm; Riedl, Stefan; Brämswig, Jürgen; Richter-Unruh, Annette; Fricke-Otto, Susanne; Hübner, Angela; Bettendorf, Markus; Schönau, Eckhard; Dörr, Helmut; Holl, Reinhard W; Mohnike, Klaus

2018-01-01

Sodium chloride supplementation in salt-wasting congenital adrenal hyperplasia (CAH) is generally recommended in infants, but its implementation in routine care is very heterogeneous. To evaluate oral sodium chloride supplementation, growth, and hydrocortisone and fludrocortisone dose in infants with salt-wasting CAH due to 21-hydroxylase in 311 infants from the AQUAPE CAH database. Of 358 patients with classic CAH born between 1999 and 2015, 311 patients had salt-wasting CAH (133 females, 178 males). Of these, 86 patients (27.7%) received oral sodium chloride supplementation in a mean dose of 0.9 ± 1.4 mmol/kg/day (excluding nutritional sodium content) during the first year of life. 225 patients (72.3%) were not treated with sodium chloride. The percentage of sodium chloride-supplemented patients rose from 15.2% in children born 1999-2004 to 37.5% in children born 2011-2015. Sodium chloride-supplemented and -unsupplemented infants did not significantly differ in hydrocortisone and fludrocortisone dose, target height-corrected height-SDS, and BMI-SDS during the first 2 years of life. In the AQUAPE CAH database, approximately one-third of infants with salt-wasting CAH receive sodium chloride supplementation. Sodium chloride supplementation is performed more frequently in recent years. However, salt supplementation had no influence on growth, daily fludrocortisone and hydrocortisone dose, and frequency of adrenal crisis. © 2017 S. Karger AG, Basel.

New approach to description of (d,xn) spectra at energies below 50 MeV in Monte Carlo simulation by intra-nuclear cascade code with Distorted Wave Born Approximation

NASA Astrophysics Data System (ADS)

Hashimoto, S.; Iwamoto, Y.; Sato, T.; Niita, K.; Boudard, A.; Cugnon, J.; David, J.-C.; Leray, S.; Mancusi, D.

2014-08-01

A new approach to describing neutron spectra of deuteron-induced reactions in the Monte Carlo simulation for particle transport has been developed by combining the Intra-Nuclear Cascade of Liège (INCL) and the Distorted Wave Born Approximation (DWBA) calculation. We incorporated this combined method into the Particle and Heavy Ion Transport code System (PHITS) and applied it to estimate (d,xn) spectra on natLi, 9Be, and natC targets at incident energies ranging from 10 to 40 MeV. Double differential cross sections obtained by INCL and DWBA successfully reproduced broad peaks and discrete peaks, respectively, at the same energies as those observed in experimental data. Furthermore, an excellent agreement was observed between experimental data and PHITS-derived results using the combined method in thick target neutron yields over a wide range of neutron emission angles in the reactions. We also applied the new method to estimate (d,xp) spectra in the reactions, and discussed the validity for the proton emission spectra.

Calculation of the age of the first infection for skin sores and scabies in five remote communities in northern Australia.

PubMed

Lydeamore, M J; Campbell, P T; Cuningham, W; Andrews, R M; Kearns, T; Clucas, D; Gundjirryirr Dhurrkay, R; Carapetis, J; Tong, S Y C; McCaw, J M; McVernon, J

2018-05-08

Prevalence of skin sores and scabies in remote Australian Aboriginal communities remains unacceptably high, with Group A Streptococcus (GAS) the dominant pathogen. We aim to better understand the drivers of GAS transmission using mathematical models. To estimate the force of infection, we quantified the age of first skin sores and scabies infection by pooling historical data from three studies conducted across five remote Aboriginal communities for children born between 2001 and 2005. We estimated the age of the first infection using the Kaplan-Meier estimator; parametric exponential mixture model; and Cox proportional hazards. For skin sores, the mean age of the first infection was approximately 10 months and the median was 7 months, with some heterogeneity in median observed by the community. For scabies, the mean age of the first infection was approximately 9 months and the median was 8 months, with significant heterogeneity by the community and an enhanced risk for children born between October and December. The young age of the first infection with skin sores and scabies reflects the high disease burden in these communities.

Relativistic corrections to the ground state of H2 calculated without using the Born-Oppenheimer approximation

NASA Astrophysics Data System (ADS)

Wang, L. M.; Yan, Z.-C.

2018-06-01

The Schrödinger equation for the ground state of the hydrogen molecule H2 is solved by applying the Rayleigh-Ritz variational method in Hylleraas coordinates without using the Born-Oppenheimer approximation. The nonrelativistic energy eigenvalue is converged to -1.164 025 030 880 (7 ) atomic units. The leading-order relativistic corrections, including the mass-velocity, Darwin, orbit-orbit, spin-spin, and relativistic recoil terms, are evaluated perturbatively. Together with the higher-order relativistic and quantum electrodynamic corrections obtained by Puchalski et al. [Phys. Rev. Lett. 117, 263002 (2016), 10.1103/PhysRevLett.117.263002], we determine the dissociation energy of the hydrogen molecule, D0=36 118.069 71 (33 ) cm-1 , which agrees with the two recent experimental results of Liu et al. [J. Chem. Phys. 130, 174306 (2009), 10.1063/1.3120443], 36 118.069 62 (37 ) cm-1 , and Altmann et al. [Phys. Rev. Lett. 120, 043204 (2018), 10.1103/PhysRevLett.120.043204], 36 118.069 45 (31 ) cm-1 .

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

Carbajal, L.; Warwick Univ., Coventry; Dendy, R. O.

Ion cyclotron emission (ICE) offers unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity P ICE scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, n /n i , of fusion-born alpha-particles confined within the plasma. We present fully nonlinear self-consistent kinetic simulations that reproduce this scaling for the first time. This resolves a longstanding question in the physics of fusion alpha particle confinement and stability in MCF plasmas. It confirms the MCI as the likely emissionmore » mechanism and greatly strengthens the basis for diagnostic exploitation of ICE in future burning plasmas.« less

Calculation of total electron excitation cross-sections and partial electron ionization cross-sections for the elements. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Green, T. J.

1973-01-01

Computer programs were used to calculate the total electron excitation cross-section for atoms and the partial ionization cross-section. The approximations to the scattering amplitude used are as follows: (1) Born, Bethe, and Modified Bethe for non-exchange excitation; (2) Ochkur for exchange excitation; and (3) Coulomb-Born of non-exchange ionization. The amplitudes are related to the differential cross-sections which are integrated to give the total excitation (or partial ionization) cross-section for the collision. The atomic wave functions used are Hartree-Fock-Slater functions for bound states and the coulomb wave function for the continuum. The programs are presented and the results are examined.

The PoGO+ Ballon-Borne Hard X-ray Polarimetry Mission

NASA Astrophysics Data System (ADS)

Friis, Mette; Kiss, Mózsi; Mikhalev, Victor; Pearce, Mark; Takahashi, Hiromitsu

2018-03-01

The PoGO mission, including the PoGOLite Pathfinder and PoGO+, aims to provide polarimetric measurements of the Crab system and Cygnus X-1 in the hard X-ray band. Measurements are conducted from a stabilized balloon-borne platform, launched on a 1 million cubic meter balloon from the Esrange Space Center in Sweden to an altitude of approximately 40 km. Several flights have been conducted, resulting in two independent measurements of the Crab polarization and one of Cygnus X-1. Here, a review of the PoGO mission is presented, including a description of the payload and the flight campaigns, and a discussion of some of the scientific results obtained to date.

2-D Fused Image Reconstruction approach for Microwave Tomography: a theoretical assessment using FDTD Model.

PubMed

Bindu, G; Semenov, S

2013-01-01

This paper describes an efficient two-dimensional fused image reconstruction approach for Microwave Tomography (MWT). Finite Difference Time Domain (FDTD) models were created for a viable MWT experimental system having the transceivers modelled using thin wire approximation with resistive voltage sources. Born Iterative and Distorted Born Iterative methods have been employed for image reconstruction with the extremity imaging being done using a differential imaging technique. The forward solver in the imaging algorithm employs the FDTD method of solving the time domain Maxwell's equations with the regularisation parameter computed using a stochastic approach. The algorithm is tested with 10% noise inclusion and successful image reconstruction has been shown implying its robustness.

Mortality among US-born and immigrant Hispanics in the US: effects of nativity, duration of residence, and age at immigration.

PubMed

Holmes, Julia S; Driscoll, Anne K; Heron, Melonie

2015-07-01

We examined the effects of duration of residence and age at immigration on mortality among US-born and foreign-born Hispanics aged 25 and older. We analyzed the National Health Interview Survey-National Death Index linked files from 1997-2009 with mortality follow-up through 2011. We used Cox proportional hazard models to examine the effects of duration of US residence and age at immigration on mortality for US-born and foreign-born Hispanics, controlling for various demographic, socioeconomic and health factors. Age at immigration included 4 age groups: <18, 18-24, 25-34, and 35+ years. Duration of residence was 0-15 and >15 years. We observed a mortality advantage among Hispanic immigrants compared to US-born Hispanics only for those who had come to the US after age 24 regardless of how long they had lived in the US. Hispanics who immigrated as youths (<18) did not differ from US-born Hispanics on mortality despite duration of residence. Findings suggest that age at immigration, rather than duration of residence, drives differences in mortality between Hispanic immigrants and the US-born Hispanic population.

Foreign-born Peers and Academic Performance.

PubMed

Conger, Dylan

2015-04-01

The academic performance of foreign-born youth in the United States is well studied, yet little is known about whether and how foreign-born students influence their classmates. In this article, I develop a set of expectations regarding the potential consequences of immigrant integration across schools, with a distinction between the effects of sharing schools with immigrants who are designated as English language learners (ELL) and those who are not. I then use administrative data on multiple cohorts of Florida public high school students to estimate the effect of immigrant shares on immigrant and native-born students' academic performance. The identification strategy pays careful attention to the selection problem by estimating the effect of foreign-born peers from deviations in the share foreign-born across cohorts of students attending the same school in different years. The assumption underlying this approach is that students choose schools based on the composition of the entire school, not on the composition of each entering cohort. The results of the analysis, which hold under several robustness checks, indicate that foreign-born peers (both those who are ELL and those who are non-ELL) have no effect on their high school classmates' academic performance.

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.

Later-borns Don't Give Up: The Temporary Effects of Birth Order on European Earnings.

PubMed

Bertoni, Marco; Brunello, Giorgio

2016-04-01

The existing empirical evidence on the effects of birth order on wages does not distinguish between temporary and permanent effects. Using data from 11 European countries for males born between 1935 and 1956, we show that firstborns enjoy on average a 13.7% premium in their entry wage compared with later-borns. This advantage, however, is short-lived and disappears 10 years after labor market entry. Although firstborns start with a better job, partially because of their higher education, later-borns quickly catch up by switching earlier and more frequently to better-paying jobs. We argue that a key factor driving our findings is that later-borns have lower risk aversion than firstborns.

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.

A finite element study on the effects of midsymphyseal distraction osteogenesis on the mandible and articular disc.

PubMed

Kim, Ki-Nam; Cha, Bong-Kuen; Choi, Dong-Soon; Jang, Insan; Yi, Yang-Jin; Jost-Brinkmann, Paul-Georg

2012-05-01

To evaluate the biomechanical effect of midsymphyseal distraction osteogenesis with three types of distractors on the mandible and articular disc using a three-dimensional finite element model analysis. A virtual model of the mandible was produced from computed tomography scan images of a healthy 27-year-old man. On the finite element model of the mandible, expansion of the bone-borne, tooth-borne, and hybrid type distractors were simulated with the jaw-closing muscles. The displacement and stress distribution of the mandible and articular disc were analyzed. With the bone-borne appliance the alveolar process area was displaced more than the basal bone area. The tooth-borne appliance displaced the mandibular body in a parallel manner and showed high level of the von Mises stress in the alveolar process and the ramal region as well as in the condylar neck area. The hybrid type showed medium amount of displacement and stress distribution compared with the bone-borne and tooth-borne type. At the articular disc the compressive stress was concentrated in the anteromedial and posterolateral area, and it was highest in the tooth-borne distractor, followed by hybrid appliance and bone-borne appliance. The tooth-borne distractor produced more parallel bony widening in the midsymphyseal area and larger expansion in the molar region; however, it induced higher stress concentration on the articular disc than the hybrid appliance and bone-borne appliance. Whether any long-term side effects on the temporomandibular joint are anticipated, especially in tooth-borne distractor, remains to be investigated.

Exact and approximate many-body dynamics with stochastic one-body density matrix evolution

NASA Astrophysics Data System (ADS)

Lacroix, Denis

2005-06-01

We show that the dynamics of interacting fermions can be exactly replaced by a quantum jump theory in the many-body density matrix space. In this theory, jumps occur between densities formed of pairs of Slater determinants, Dab=|Φa><Φb|, where each state evolves according to the stochastic Schrödinger equation given by O. Juillet and Ph. Chomaz [Phys. Rev. Lett. 88, 142503 (2002)]. A stochastic Liouville-von Neumann equation is derived as well as the associated. Bogolyubov-Born-Green-Kirwood-Yvon hierarchy. Due to the specific form of the many-body density along the path, the presented theory is equivalent to a stochastic theory in one-body density matrix space, in which each density matrix evolves according to its own mean-field augmented by a one-body noise. Guided by the exact reformulation, a stochastic mean-field dynamics valid in the weak coupling approximation is proposed. This theory leads to an approximate treatment of two-body effects similar to the extended time-dependent Hartree-Fock scheme. In this stochastic mean-field dynamics, statistical mixing can be directly considered and jumps occur on a coarse-grained time scale. Accordingly, numerical effort is expected to be significantly reduced for applications.

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.

Do mother's education and foreign born status interact to influence birth outcomes? Clarifying the epidemiological paradox and the healthy migrant effect.

PubMed

Auger, N; Luo, Z-C; Platt, R W; Daniel, M

2008-05-01

The unresolved "epidemiological paradox" concerns the association between low socioeconomic status and unexpectedly favourable birth outcomes in foreign born mothers. The "healthy migrant" effect concerns the association between foreign born status per se and birth outcomes. The epidemiological paradox and healthy migrant effect were analysed for newborns in a favourable sociopolitical environment. 98,330 live births to mothers in Montreal, Canada from 1997 to 2001 were analysed. Mothers were categorised as foreign born versus Canadian born. Outcomes were: small for gestational age (SGA) birth; low birth weight (LBW) and preterm birth (PTB). Multilevel logistic regression was used to examine the interaction between maternal education and foreign born status, adjusting for covariates. Not having a high school diploma was associated with LBW in Canadian (odds ratio (OR) 3.20; 95% CI 2.61 to 3.91) but not foreign born (OR 1.14; 95% CI 0.99 to 2.10) mothers and was more strongly associated with SGA birth in Canadian (OR 2.03; 95% CI 1.84 to 2.22) than in foreign born (OR 1.26; 95% CI 1.07 to 1.49) mothers. Foreign born status was associated with SGA birth (OR 1.37; 95% CI 1.28 to 1.47), LBW (OR 1.51; 95% CI 1.27 to 1.79) and PTB (OR 1.12; 95% CI 1.03 to 1.22) in university-educated mothers only. The epidemiological paradox associated with low educational attainment was present for SGA birth and LBW but not PTB. Foreign born status was associated with adverse birth outcomes in university-educated mothers, the opposite of the healthy migrant effect.

Electron-Phonon and Electron-Electron Interactions in Individual Suspended Carbon Nanotubes

NASA Astrophysics Data System (ADS)

Cronin, Stephen

2010-03-01

The fabrication of pristine, nearly defect-free, suspended carbon nanotubes (CNTs) enables the observation of several phenomena not seen before in carbon nanotubes, including breakdown of the Born-Oppenheimer approximation^1, mode selective electron-phonon coupling^2, and a Mott insulator transition^3. Raman spectroscopy of these nanotubes under applied gate and bias potentials reveals exceptionally strong electron-phonon coupling, arising from Kohn anomalies, which result in mode selective electron-phonon coupling, negative differential conductance (NDC), and non-equilibrium phonon populations^2,4. Due to the extremely long electron lifetimes, we observe a breakdown of the Born-Oppenheimer approximation, as deduced from the gate voltage-induced changes in the vibrational energies of suspended carbon nanotubes^1. We also report strikingly large variations in the Raman intensity of pristine metallic CNTs in response to gate voltages, which are attributed to a Mott insulating state of the strongly correlated electrons^3. As will be shown, preparing clean, defect-free devices is an essential prerequisite for studying the rich low-dimensional physics of CNTs. (1.) Bushmaker, A.W., Deshpande, V.V., Hsieh, S., Bockrath, M.W., and Cronin, S.B., ``Direct Observation of Born-Oppenheimer Approximation Breakdown in Carbon Nanotubes.'' Nano Letters, 9, 607 (2009). (2.) Bushmaker, A.W., Deshpande, V.V., Bockrath, M.W., and Cronin, S.B., ``Direct Observation of Mode Selective Electron-Phonon Coupling in Suspended Carbon Nanotubes.'' Nano Letters, 7, 3618 (2007) (3.) Bushmaker, A.W., Deshpande, V.V., Hsieh, S., Bockrath, M.W., and Cronin, S.B., ``Large Modulations in the Intensity of Raman-Scattered Light from Pristine Carbon Nanotubes.'' Physical Review Letters, 103, 067401 (2009). (4.) Bushmaker, A.W., Deshpande, V.V., Hsieh, S., Bockrath, M.W., and Cronin, S.B., ``Gate Voltage Controlled Non-Equilibrium and Non-Ohmic Behavior in Suspended Carbon Nanotubes.'' Nano Letters, 9, 2862 (2009)

Hypertrophic pyloric stenosis in infants following pertussis prophylaxis with erythromycin--Knoxville, Tennessee, 1999.

PubMed

1999-12-17

In February 1999, pertussis was diagnosed in six neonates born at hospital A in Knoxville, Tennessee. Because a health-care worker at hospital A was most likely the source of exposure, the local health department recommended on February 25, 1999, that erythromycin be prescribed as postexposure prophylaxis for the approximately 200 infants born at hospital A during February 1-24, 1999. In March 1999, local pediatric surgeons noticed an increased number of cases of infantile hypertrophic pyloric stenosis (IHPS) in the area, with seven cases occurring during a 2-week period. All seven IHPS cases were in infants born in hospital A during February who were given erythromycin orally for prophylaxis following possible exposure to pertussis, although none had pertussis diagnosed. The Tennessee Department of Health and CDC investigated the cluster of IHPS cases and its possible association with use of erythromycin. This report summarizes the results of the investigation, which suggest a causal role of erythromycin in this cluster of IHPS cases.

Neonatal infrared axillary thermometry.

PubMed

Seguin, J; Terry, K

1999-01-01

The authors compared axillary skin temperatures (AT) measured with an infrared (IR) thermometer (Lightouch Neonate, Exergen Corp) with rectal temperatures (RT) in 16 newly born term infants under radiant warmers (RW) and in cribs. Twelve stable, growing premature infants in incubators were also studied. This new device may be useful because of safety and rapid results (1 second), but clinical accuracy is unknown. For term infants, mean (SD) RT-AT difference was 0.1 (0.48) degree C under RW and 0.25 (0.17) degree C 2 hours later in cribs. For premature infants in incubators the mean RT-AT difference was 0.09 (0.16) degree C. Axillary temperatures measured by IR thermometer approximate RT for newly born term infants in cribs and stable premature infants in incubators. For newly born term infants under RW, RT-AT differences vary more widely, limiting clinical usefulness in this setting. The device, the unique age of this population, and the RW environment may play a role.

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.

Average-atom treatment of relaxation time in x-ray Thomson scattering from warm dense matter.

PubMed

Johnson, W R; Nilsen, J

2016-03-01

The influence of finite relaxation times on Thomson scattering from warm dense plasmas is examined within the framework of the average-atom approximation. Presently most calculations use the collision-free Lindhard dielectric function to evaluate the free-electron contribution to the Thomson cross section. In this work, we use the Mermin dielectric function, which includes relaxation time explicitly. The relaxation time is evaluated by treating the average atom as an impurity in a uniform electron gas and depends critically on the transport cross section. The calculated relaxation rates agree well with values inferred from the Ziman formula for the static conductivity and also with rates inferred from a fit to the frequency-dependent conductivity. Transport cross sections determined by the phase-shift analysis in the average-atom potential are compared with those evaluated in the commonly used Born approximation. The Born approximation converges to the exact cross sections at high energies; however, differences that occur at low energies lead to corresponding differences in relaxation rates. The relative importance of including relaxation time when modeling x-ray Thomson scattering spectra is examined by comparing calculations of the free-electron dynamic structure function for Thomson scattering using Lindhard and Mermin dielectric functions. Applications are given to warm dense Be plasmas, with temperatures ranging from 2 to 32 eV and densities ranging from 2 to 64 g/cc.

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

Johnson, W. R.; Nilsen, J.

Here, the influence of finite relaxation times on Thomson scattering from warm dense plasmas is examined within the framework of the average-atom approximation. Presently most calculations use the collision-free Lindhard dielectric function to evaluate the free-electron contribution to the Thomson cross section. In this work, we use the Mermin dielectric function, which includes relaxation time explicitly. The relaxation time is evaluated by treating the average atom as an impurity in a uniform electron gas and depends critically on the transport cross section. The calculated relaxation rates agree well with values inferred from the Ziman formula for the static conductivity andmore » also with rates inferred from a fit to the frequency-dependent conductivity. Transport cross sections determined by the phase-shift analysis in the average-atom potential are compared with those evaluated in the commonly used Born approximation. The Born approximation converges to the exact cross sections at high energies; however, differences that occur at low energies lead to corresponding differences in relaxation rates. The relative importance of including relaxation time when modeling x-ray Thomson scattering spectra is examined by comparing calculations of the free-electron dynamic structure function for Thomson scattering using Lindhard and Mermin dielectric functions. Applications are given to warm dense Be plasmas, with temperatures ranging from 2 to 32 eV and densities ranging from 2 to 64 g/cc.« less

Average-atom treatment of relaxation time in x-ray Thomson scattering from warm dense matter

DOE PAGES

Johnson, W. R.; Nilsen, J.

2016-03-14

Here, the influence of finite relaxation times on Thomson scattering from warm dense plasmas is examined within the framework of the average-atom approximation. Presently most calculations use the collision-free Lindhard dielectric function to evaluate the free-electron contribution to the Thomson cross section. In this work, we use the Mermin dielectric function, which includes relaxation time explicitly. The relaxation time is evaluated by treating the average atom as an impurity in a uniform electron gas and depends critically on the transport cross section. The calculated relaxation rates agree well with values inferred from the Ziman formula for the static conductivity andmore » also with rates inferred from a fit to the frequency-dependent conductivity. Transport cross sections determined by the phase-shift analysis in the average-atom potential are compared with those evaluated in the commonly used Born approximation. The Born approximation converges to the exact cross sections at high energies; however, differences that occur at low energies lead to corresponding differences in relaxation rates. The relative importance of including relaxation time when modeling x-ray Thomson scattering spectra is examined by comparing calculations of the free-electron dynamic structure function for Thomson scattering using Lindhard and Mermin dielectric functions. Applications are given to warm dense Be plasmas, with temperatures ranging from 2 to 32 eV and densities ranging from 2 to 64 g/cc.« less

Strong-potential Born calculations for 1s-1s electron capture from atoms by protons

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

McGuire, J.H.; Kletke, R.E.; Sil, N.C.

1985-08-01

The strong-potential Born (SPB) approximation is examined by comparing various SPB calculations of high-velocity 1s-1s electron capture cross sections with one another and with experimental data. Above about 1 MeV, calculations using the SPB method of McGuire and Sil (SPMS) (Phys. Rev. A 28, 3679 (1983)) are in good agreement with total-cross-section observations for protons on H, He, C, Ne, and Ar as expected. For p+H and p+He, the SPB full-peaking (SPB-FP) approximation of Macek and Alston (Phys. Rev. A 26, 250 (1982)) and the SPB transverse-peaking (SPB-TP) approximation of Alston (Phys. Rev. A 27, 2342 (1982)) differ from ourmore » SPMS total cross sections by typically a factor of 2, as expected from general validity criteria. However, the differential cross sections at very forward angles (well within the Thomas angle) are the same in SPMS, SPB-FP, and SPB-TP methods in all cases. Below 1 MeV, cross sections obtained with use of various SPB methods differ considerably from one another, placing a limit of validity for these SPB calculations. We also suggest that in the gap between those energies where continuum intermediate states simply dominate, and above those energies where bound intermediate states simply dominate, detailed conceptual understanding of electron capture is incomplete.« less

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

Eich, F. G.; Agostini, Federica, E-mail: agostini@mpi-halle.mpg.de

We propose a procedure to analyze the relation between the exact factorization of the electron-nuclear wave function and the Born-Oppenheimer approximation. We define the adiabatic limit as the limit of infinite nuclear mass. To this end, we introduce a unit system that singles out the dependence on the electron-nuclear mass ratio of each term appearing in the equations of the exact factorization. We observe how non-adiabatic effects induced by the coupling to the nuclear motion affect electronic properties and we analyze the leading term, connecting it to the classical nuclear momentum. Its dependence on the mass ratio is tested numericallymore » on a model of proton-coupled electron transfer in different non-adiabatic regimes.« less

Strong potential wave functions with elastic channel distortion

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

Macek, J.; Taulbjerg, K.

1989-06-01

The strong-potential Born approximation is analyzed in a channel-distorted-wave approach. Channel-distorted SPB wave functions are reduced to a conventional form in which the standard off-energy-shell factor /ital g/ has been replaced by a modified factor ..gamma.., which represents a suitable average of /ital g/ over the momentum distribution of the distorted-channel function. The modified factor is evaluated in a physically realistic model for the distortion potential, and it is found that ..gamma.. is well represented by a slowly varying phase factor. The channel-distorted SPB approximation is accordingly identical to the impulse approximation if the phase variation of ..gamma.. can bemore » ignored. This is generally the case in applications to radiative electron capture and to a good approximation for ordinary capture at not too small velocities.« less

The Willingness to Pay for Vaccination against Tick-Borne Encephalitis and Implications for Public Health Policy: Evidence from Sweden.

PubMed

Slunge, Daniel

2015-01-01

The increasing incidence of tick-borne encephalitis (TBE) in Sweden and several other European countries has sparked a discussion about the need for a public vaccination strategy. However, TBE vaccination coverage is incomplete and there is little knowledge about the factors influencing vaccination behavior. Based on a survey of 1,500 randomly selected respondents in Sweden, we estimate vaccination coverage in areas with different TBE risk levels and analyze the role of vaccine price and other factors influencing the demand for vaccination. First, we find that the average rate of TBE vaccination in Sweden is 33% in TBE risk areas and 18% elsewhere. Income, age and risk-related factors such as incidence of TBE in the area of residence, frequency of visits to areas with TBE risk, and experience with tick bites are positively associated with demand for TBE vaccine. Next, using contingent valuation methodology, we estimate the willingness to pay for TBE vaccination among the unvaccinated respondents and the effect of a possible subsidy. Among the unvaccinated respondents in TBE risk areas, we estimate the mean willingness to pay for the recommended three doses of TBE vaccine to be 465 SEK (approximately 46 euros or 40% of the current market price). We project that a subsidy making TBE vaccines free of charge could increase the vaccination rate in TBE risk areas to around 78%, with a larger effect on low-income households, whose current vaccination rate is only 15% in risk areas. However, price is not the only factor affecting demand. We find significant effects on vaccination behavior associated with trust in vaccine recommendations, perceptions about tick bite-related health risks and knowledge about ticks and tick-borne diseases. Hence, increasing knowledge and trust, as well as ease of access to vaccinations, can also be important measures for public health agencies that want to increase the vaccination rate.

The Willingness to Pay for Vaccination against Tick-Borne Encephalitis and Implications for Public Health Policy: Evidence from Sweden

PubMed Central

Slunge, Daniel

2015-01-01

The increasing incidence of tick-borne encephalitis (TBE) in Sweden and several other European countries has sparked a discussion about the need for a public vaccination strategy. However, TBE vaccination coverage is incomplete and there is little knowledge about the factors influencing vaccination behavior. Based on a survey of 1,500 randomly selected respondents in Sweden, we estimate vaccination coverage in areas with different TBE risk levels and analyze the role of vaccine price and other factors influencing the demand for vaccination. First, we find that the average rate of TBE vaccination in Sweden is 33% in TBE risk areas and 18% elsewhere. Income, age and risk-related factors such as incidence of TBE in the area of residence, frequency of visits to areas with TBE risk, and experience with tick bites are positively associated with demand for TBE vaccine. Next, using contingent valuation methodology, we estimate the willingness to pay for TBE vaccination among the unvaccinated respondents and the effect of a possible subsidy. Among the unvaccinated respondents in TBE risk areas, we estimate the mean willingness to pay for the recommended three doses of TBE vaccine to be 465 SEK (approximately 46 euros or 40% of the current market price). We project that a subsidy making TBE vaccines free of charge could increase the vaccination rate in TBE risk areas to around 78%, with a larger effect on low-income households, whose current vaccination rate is only 15% in risk areas. However, price is not the only factor affecting demand. We find significant effects on vaccination behavior associated with trust in vaccine recommendations, perceptions about tick bite-related health risks and knowledge about ticks and tick-borne diseases. Hence, increasing knowledge and trust, as well as ease of access to vaccinations, can also be important measures for public health agencies that want to increase the vaccination rate. PMID:26641491

Does time since immigration modify neighborhood deprivation gradients in preterm birth? A multilevel analysis.

PubMed

Urquia, Marcelo Luis; Frank, John William; Moineddin, Rahim; Glazier, Richard Henry

2011-10-01

Immigrants' health is jointly influenced by their pre- and post-migration exposures, but how these two influences operate with increasing duration of residence has not been well-researched. We aimed to examine how the influence of maternal country of birth and neighborhood deprivation effects, if any, change over time since migration and how neighborhood effects among immigrants compare with those observed in the Canadian-born population. Birth data from Ontario hospital records (2002-2007) were linked with an official Canadian immigration database (1985-2000). The outcome measure was preterm birth. Neighborhoods were ranked according to a neighborhood deprivation index developed for Canadian urban areas and collapsed into tertiles of approximately equal size. Time since immigration was measured from the date of arrival to Canada to the date of delivery, ranging from 1 to 22 years. We used cross-classified random effect models to simultaneously account for the membership of births (N = 83,233) to urban neighborhoods (N = 1,801) and maternal countries of birth (N = 168). There were no differences in preterm birth between neighborhood deprivation tertiles among immigrants with less than 15 years of residence. Among immigrants with 15 years of stay or more, the adjusted absolute risk difference (ARD%, 95% confidence interval) between high-deprived (tertile 3) and low-deprived (tertile 1) neighborhoods was 1.86 (0.68, 2.98), while the ARD% observed among the Canadian-born (N = 314,237) was 1.34 (1.11, 1.57). Time since migration modifies the neighborhood deprivation gradient in preterm birth among immigrants living in Ontario cities. Immigrants reached the level of inequalities in preterm birth observed at the neighborhood level among the Canadian-born after 14 years of stay, but neighborhoods did not influence preterm birth among more recent immigrants, for whom the maternal country of birth was more predictive of preterm birth.

Evaluation of the Impact of Mandating Health Care Providers to Offer Hepatitis C Virus Screening to All Persons Born During 1945-1965 - New York, 2014.

PubMed

Flanigan, Colleen A; Leung, Shu-Yin J; Rowe, Kirsten A; Levey, Wendy K; King, Andrea; Sommer, Jamie N; Morne, Johanne E; Zucker, Howard A

2017-09-29

Approximately 75% of all hepatitis C virus (HCV) infections in the United States and 73% of HCV-associated mortality occur in persons born during 1945-1965, placing this birth cohort at increased risk for liver cancer and other HCV-related liver disease (1). In the United States, an estimated 2.7 million persons are living with HCV infection, and it is estimated that up to 75% of these persons do not know their status. Since 2012, CDC has recommended that persons born during 1945-1965 receive one-time HCV testing. To increase the number of persons tested for HCV and to ensure timely diagnosis and linkage to care, in 2014, New York enacted a hepatitis C testing law that requires health care providers to offer HCV antibody screening to all persons born during 1945-1965 who are receiving services in primary care settings or as hospital inpatients, and to refer persons with positive HCV antibody tests for follow-up health care, including an HCV diagnostic test (i.e., HCV RNA).* The New York State Department of Health (NYSDOH) used survey data from clinical laboratories and Medicaid claims and encounter data, and state and New York City (NYC) HCV surveillance data to assess the number of persons tested for HCV and number of persons with newly diagnosed HCV infections who were linked to care. During the first year of the HCV law implementation, there was a 51% increase in specimens submitted for HCV testing to surveyed clinical laboratories; testing rates among active Medicaid clients increased 52%, and linkage to care among persons with newly diagnosed HCV infection increased approximately 40% in New York and 11% in NYC. These findings highlight the potential for state laws to promote HCV testing and the utility of HCV surveillance and Medicaid claims data to monitor the quality of HCV testing and linkage to care for HCV-infected persons.

Resonant nuclear scattering of synchrotron radiation: Detector development and specular scattering from a thin layer of {sup 57}Fe

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

Baron, A.Q.R.

1995-04-01

This thesis explores resonant nudear scattering of synchrotron radiation. An introductory chapter describes some useful concepts, such as speedup and coherent enhancement, in the context of some basic physical principles. Methods of producing highly monochromatic synchrotron beams usmg either electronic or nuclear scattering are also discussed. The body of the thesis concentrates on detector development and specular scattering from iynthetic layered materials. A detector employing n-dcrochannel plate electron multipliers is shown to have good ({approximately}50%) effidency for detecting 14.4 key x-rays incident at small ({approximately}0.5 degree) grazing angles onto Au or CsI photocathodes. However, being complicated to use, it wasmore » replaced with a large area (>=lan2) avalanche photodiode (APD) detector. The APD`s are simpler to use and have comparable (30--70%) efficiencies at 14.4 key, subnanosecond time resolution, large dynan-dc range (usable at rates up to {approximately}10{sup 8} photons/second) and low (<{approximately}0.01 cts/sec) background rates. Maxwell`s equations are used to derive the specular x-ray reflectivity of layered materials with resonant transitions and complex polarization dependencies. The effects of interfadal roughness are treated with some care, and the distorted wave Born approximation (DWBA) used to describe electronic scattering is generalized to the nuclear case. The implications of the theory are discussed in the context of grazing incidence measurements with emphasis on the kinematic and dynamical aspects of the scattering.« less

Hyperemesis gravidarum and pregnancy outcomes in the Norwegian Mother and Child Cohort - a cohort study.

PubMed

Vikanes, Åse V; Støer, Nathalie C; Magnus, Per; Grjibovski, Andrej M

2013-09-03

Hyperemesis gravidarum (HG) characterized by excessive nausea and vomiting in early pregnancy, is reported to be associated with increased risks for low birthweight (LBW), preterm birth (PTB), small-for-gestational-age (SGA) and perinatal death. Conflicting results in previous studies underline the necessity to study HG's potential effect on pregnancy outcomes using large cohorts with valid data on exposure and outcome measures, as well as potential confounders. This study aims to investigate associations between HG and adverse pregnancy outcomes using the Norwegian Mother and Child Cohort Study (MoBa). All singleton pregnancies in MoBa from 1998 to 2008 were included. Multivariable regression was used to estimate relative risks, approximated by odds ratios, for PTB, LBW, SGA and perinatal death. Linear regression was applied to assess differences in birthweight and gestational age for children born to women with and without HG. Potential confounders were adjusted for. Altogether, 814 out of 71,468 women (or 1.1%) had HG. In MoBa HG was not associated with PTB, LBW or SGA. Babies born to women with HG were born on average 1 day earlier than those born to women without HG; (-0.97 day (95% confidence intervals (CI): -1.80 - -0.15). There was no difference in birthweight when maternal weight gain was adjusted for; (23.42 grams (95% CI: -56.71 - 9.86). Babies born by women with HG had lower risk for having Apgar score < 7 after 1 minute (crude odds ratio was 0.64 (95% CI: 0.43 - 0.95)). No differences between the groups for Apgar score < 7 after 5 minutes were observed. Time-point for hospitalisation slightly increased differences in gestational age according to maternal HG status. HG was not associated with adverse pregnancy outcomes. Pregnancies complicated with HG had a slightly shorter gestational length. There was no difference in birth weight according to maternal HG-status. HG was associated with an almost 40% reduced risk for having Apgar score < 7 after 1 minute, but not after 5 minutes. The clinical importance of these statistically significant findings is, however, rather limited.

Functional Brain Organization for Number Processing in Pre-Verbal Infants

ERIC Educational Resources Information Center

Edwards, Laura A.; Wagner, Jennifer B.; Simon, Charline E.; Hyde, Daniel C.

2016-01-01

Humans are born with the ability to mentally represent the approximate numerosity of a set of objects, but little is known about the brain systems that sub-serve this ability early in life and their relation to the brain systems underlying symbolic number and mathematics later in development. Here we investigate processing of numerical magnitudes…

Genetic evaluation of the probability of lambing in yearling Targhee ewes

USDA-ARS?s Scientific Manuscript database

The objective of this study was to determine the additive genetic control of lambing percentage in yearling Targhee ewes. The records of 3,103 ewe lambs born from 1989 to 2011 and mated at approximately 7.5 mo of age were analyzed. Records included sire, dam, weaning weight, breeding pen, age of dam...

New Utrecht High School Project IMPACT. O.E.E. Evaluation Report, 1982-1983.

ERIC Educational Resources Information Center

Bulkin, Elly; Sica, Michael

Project IMPACT, a magnet program in its third and final year of funding, provided instruction in ESL and Italian language skills, as well as bilingual instruction in mathematics, social studies and typing to approximately 200 students of limited English proficiency in a Brooklyn, New York, high school. Nearly all program students were born in…

Project KANPE, 1982-1983. O.E.E. Evaluation Report.

ERIC Educational Resources Information Center

Clesca, Monique; And Others

This report describes Project KANPE, a multi-site program. In its final year of a three-year funding cycle, the project served approximately 275 Haitian students of limited English proficiency in grades nine through twelve at three New York City high schools. Ninety-six percent of the target population were born in Haiti and all spoke either…

Do Twins Have Lower Cognitive Ability than Singletons?

ERIC Educational Resources Information Center

Webbink, Dinand; Posthuma, Danielle; Boomsma, Dorret I.; de Geus, Eco J. C.; Visscher, Peter M.

2008-01-01

Previous studies based on population cohorts born at least 35 years ago, have reported appreciable childhood cognitive deficits for twins. We compared longitudinal IQ scores from approximately 188,000 singletons and some 6000 twins who went to primary school in the Netherlands from 1994 to 2003. In addition, we used a family-based design in which…

Combined active and passive microwave remote sensing of soil moisture for vegetated surfaces at L-band

USDA-ARS?s Scientific Manuscript database

The distorted Born approximation (DBA) combined with the numerical solutions of Maxwell equations (NMM3D) has been used for the radar backscattering model for the SMAP mission. The models for vegetated surfaces such as wheat, grass, soybean and corn have been validated with the Soil Moisture Active ...

Numicon, Numeracy and a Special Need

ERIC Educational Resources Information Center

Horner, Vikki

2002-01-01

Charlotte, the author's 11-year-old daughter, was born with Down syndrome, and is currently attending the local middle school. In terms of her disability Charlotte is developing very well and has a reading age of 9+, however her maths skills age is approximately 4 years. It is not necessarily the case that if a child has good language and literacy…

Effect of the Mott cross section on the determination of the charge of ultraheavy cosmic rays from emulsion tracks

NASA Technical Reports Server (NTRS)

Eby, P. B.; Morgan, S. H.; Parnell, T. A.

1978-01-01

Energy deposition due to secondary electrons is calculated as a function of distance from the axis of the track of a heavy ion. The calculation incorporates the empirical formulas of Kobetich and Katz (1968) for delta-ray energy dissipation. Both the Mott and Born-approximation expressions for the delta-ray energy distributions are used, and the results are compared. The energy deposition projected along a line perpendicular to the track is also calculated. These results are used to estimate the effect that the use of the Mott cross section would have in the interpretation of photometric measurements on emulsion tracks of trans-iron cosmic-ray particles. It is shown that the use of 50 keV as a characteristic track-formation electron energy to estimate the effect of the Mott cross section systematically overestimates charge as derived from emulsions for Z greater than 20.

Semiclassical Origin of Superdeformed Shell Structure in the Spheroidal Cavity Model

NASA Astrophysics Data System (ADS)

Arita, K.; Sugita, A.; Matsuyanagi, K.

1998-12-01

Classical periodic orbits responsible for emergence of the superdeformed shell structures of single-particle motion in spheroidal cavities are identified and their relative contributions to the shell structures are evaluated. Both prolate and oblate superdeformations (axis ratio approximately 2:1) as well as prolate hyperdeformation (axis ratio approximately 3:1) are investigated. Fourier transforms of quantum spectra clearly show that three-dimensional periodic orbits born out of bifurcations of planar orbits in the equatorial plane become predominant at large prolate deformations, while butterfly-shaped planar orbits bifurcated from linear orbits along the minor axis are important at large oblate deformations.

Adult tobacco use levels after intensive tobacco control measures: New York City, 2002-2003.

PubMed

Frieden, Thomas R; Mostashari, Farzad; Kerker, Bonnie D; Miller, Nancy; Hajat, Anjum; Frankel, Martin

2005-06-01

We sought to determine the impact of comprehensive tobacco control measures in New York City. In 2002, New York City implemented a tobacco control strategy of (1) increased cigarette excise taxes; (2) legal action that made virtually all work-places, including bars and restaurants, smoke free; (3) increased cessation services, including a large-scale free nicotine-patch program; (4) education; and (5) evaluation. The health department also began annual surveys on a broad array of health measures, including smoking. From 2002 to 2003, smoking prevalence among New York City adults decreased by 11% (from 21.6% to 19.2%, approximately 140000 fewer smokers). Smoking declined among all age groups, race/ethnicities, and education levels; in both genders; among both US-born and foreign-born persons; and in all 5 boroughs. Increased taxation appeared to account for the largest proportion of the decrease; however, between 2002 and 2003 the proportion of cigarettes purchased outside New York City doubled, reducing the effective price increase by a third. Concerted local action can sharply reduce smoking prevalence. However, further progress will require national action, particularly to increase cigarette taxes, reduce cigarette tax evasion, expand education and cessation services, and limit tobacco marketing.

Born iterative reconstruction using perturbed-phase field estimates.

PubMed

Astheimer, Jeffrey P; Waag, Robert C

2008-10-01

A method of image reconstruction from scattering measurements for use in ultrasonic imaging is presented. The method employs distorted-wave Born iteration but does not require using a forward-problem solver or solving large systems of equations. These calculations are avoided by limiting intermediate estimates of medium variations to smooth functions in which the propagated fields can be approximated by phase perturbations derived from variations in a geometric path along rays. The reconstruction itself is formed by a modification of the filtered-backpropagation formula that includes correction terms to account for propagation through an estimated background. Numerical studies that validate the method for parameter ranges of interest in medical applications are presented. The efficiency of this method offers the possibility of real-time imaging from scattering measurements.

Systems and methods for locating and imaging proppant in an induced fracture

DOEpatents

Aldridge, David F.; Bartel, Lewis C.

2016-02-02

Born Scattering Inversion (BSI) systems and methods are disclosed. A BSI system may be incorporated in a well system for accessing natural gas, oil and geothermal reserves in a geologic formation beneath the surface of the Earth. The BSI system may be used to generate a three-dimensional image of a proppant-filled hydraulically-induced fracture in the geologic formation. The BSI system may include computing equipment and sensors for measuring electromagnetic fields in the vicinity of the fracture before and after the fracture is generated, adjusting the parameters of a first Born approximation model of a scattered component of the surface electromagnetic fields using the measured electromagnetic fields, and generating the image of the proppant-filled fracture using the adjusted parameters.

2-D Fused Image Reconstruction approach for Microwave Tomography: a theoretical assessment using FDTD Model

PubMed Central

Bindu, G.; Semenov, S.

2013-01-01

This paper describes an efficient two-dimensional fused image reconstruction approach for Microwave Tomography (MWT). Finite Difference Time Domain (FDTD) models were created for a viable MWT experimental system having the transceivers modelled using thin wire approximation with resistive voltage sources. Born Iterative and Distorted Born Iterative methods have been employed for image reconstruction with the extremity imaging being done using a differential imaging technique. The forward solver in the imaging algorithm employs the FDTD method of solving the time domain Maxwell’s equations with the regularisation parameter computed using a stochastic approach. The algorithm is tested with 10% noise inclusion and successful image reconstruction has been shown implying its robustness. PMID:24058889

[Occupational exposure to blood in multiple trauma care].

PubMed

Wicker, S; Wutzler, S; Schachtrupp, A; Zacharowski, K; Scheller, B

2015-01-01

Trauma care personnel are at risk of occupational exposure to blood-borne pathogens. Little is known regarding compliance with standard precautions or occupational exposure to blood and body fluids among multiple trauma care personnel in Germany. Compliance rates of multiple trauma care personnel in applying standard precautions, knowledge about transmission risks of blood-borne pathogens, perceived risks of acquiring hepatitis B, hepatitis C and human immunodeficiency virus (HIV) and the personal attitude towards testing of the index patient for blood-borne pathogens after a needlestick injury were evaluated. In the context of an advanced multiple trauma training an anonymous questionnaire was administered to the participants. Almost half of the interviewees had sustained a needlestick injury within the last 12 months. Approximately three quarters of the participants were concerned about the risk of HIV and hepatitis. Trauma care personnel had insufficient knowledge of the risk of blood-borne pathogens, overestimated the risk of hepatitis C infection and underused standard precautionary measures. Although there was excellent compliance for using gloves, there was poor compliance in using double gloves (26.4 %), eye protectors (19.7 %) and face masks (15.8 %). The overwhelming majority of multiple trauma care personnel believed it is appropriate to test an index patient for blood-borne pathogens following a needlestick injury. The process of treatment in prehospital settings is less predictable than in other settings in which invasive procedures are performed. Periodic training and awareness programs for trauma care personnel are required to increase the knowledge of occupational infections and the compliance with standard precautions. The legal and ethical aspects of testing an index patient for blood-borne pathogens after a needlestick injury of a healthcare worker have to be clarified in Germany.

Influence of residual ion polarization on the coplanar symmetric (e, 2e) cross sections for calcium and argon

NASA Astrophysics Data System (ADS)

Hu, Xiao-Qing; Chen, Zhan-Bin; Wang, Yang; Wang, Kai

2017-03-01

Detailed calculations using a modified distorted wave Born approximation (DWBA) are carried out for the triple differential cross section (TDCS) in the coplanar symmetric single ionization of calcium and argon atoms. The effects of residual ion polarization on the TDCS are investigated systematically. Our results show that the residual ion polarization, arising from the interaction between the target ion and the two outgoing electrons in the final state, may lead to a considerable change in the TDCS with a more pronounced effect in the large scattering angle region at intermediate energies. The present attempt significantly improves the agreement between theoretical and experimental results. Contribution to the Topical Issue "Atomic and Molecular Data and their Applications", edited by Gordon W.F. Drake, Jung-Sik Yoon, Daiji Kato, Grzegorz Karwasz.

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

Consequences of intrauterine growth restriction on ventilatory and thermoregulatory responses to asphyxia and hypercapnia in the newborn guinea-pig.

PubMed

Tolcos, Mary; Rees, Sandra; McGregor, Hugh; Walker, David

2002-01-01

The purpose of this study was to determine the effects of prenatal growth restriction on the ventilatory and thermoregulatory responses to asphyxia and hypercapnia in the newborn guinea-pig. Spontaneously growth-restricted (SGR) animals born to unoperated dams, and growth-retarded (GR) neonates born to dams in which a uterine artery had been ligated at mid gestation, were studied and compared with control neonates. Ventilatory responses to progressive asphyxia and steady-state hypercapnia were tested at 3-6 days of age using a barometric plethysmograph. The animals were then killed and the brains prepared for histological and immunohistochemical analysis. During progressive asphyxia, SGR neonates (n = 5) had a significantly increased minute ventilation compared with both control (n = 6) and GR (n = 5) neonates. Rectal temperature fell significantly in GR and SGR neonates after progressive asphyxia, but was unchanged in control neonates. The ventilatory responses to steady-state hypercapnia were not different in the GR, SGR and control neonates. The immunoreactive expression of glial fibrillary acidic protein, tyrosine hydroxylase, substance P and met-enkephalin in the medulla was also not different between the three groups. It was concluded that prenatal growth restriction is associated with alterations in the respiratory and thermoregulatory responses to asphyxia and hypercapnia, with greater effects observed when in utero growth restriction arises spontaneously, compared with that produced experimentally over approximately the last half of gestation.

Adverse effects of small for gestational age differ by gestational week among very preterm infants.

PubMed

Jensen, Erik A; Foglia, Elizabeth E; Dysart, Kevin C; Simmons, Rebecca A; Aghai, Zubair H; Cook, Alison; Greenspan, Jay S; DeMauro, Sara B

2018-05-05

To characterise the excess risk for death, grade 3-4 intraventricular haemorrhage (IVH), bronchopulmonary dysplasia (BPD) and stage 3-5 retinopathy of prematurity independently associated with birth small for gestational age (SGA) among very preterm infants, stratified by completed weeks of gestation. Retrospective cohort study using the Optum Neonatal Database. Study infants were born <32 weeks gestation without severe congenital anomalies. SGA was defined as a birth weight <10th percentile. The excess outcome risk independently associated with SGA birth among SGA babies was assessed using adjusted risk differences (aRDs). Of 6708 infants sampled from 717 US hospitals, 743 (11.1%) were SGA. SGA compared with non-SGA infants experienced higher unadjusted rates of each study outcome except grade 3-4 IVH among survivors. The excess risk independently associated with SGA birth varied by outcome and gestational age. The highest aRD for death (0.27; 95% CI 0.13 to 0.40) occurred among infants born at 24 weeks gestation and declined as gestational age increased. In contrast, the peak aRDs for BPD among survivors (0.32; 95% CI 0.20 to 0.44) and the composites of death or BPD (0.35; 95% CI 0.24 to 0.46) and death or major morbidity (0.35; 95% CI 0.24 to 0.45) occurred at 27 weeks gestation. The risk-adjusted probability of dying or developing one or more of the evaluated morbidities among SGA infants was similar to that of non-SGA infants born approximately 2-3 weeks less mature. The excess risk for neonatal morbidity and mortality associated with being born SGA varies by adverse outcome and gestational age. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Mother's education and the risk of several neonatal outcomes: an evidence from an Italian population-based study.

PubMed

Cantarutti, Anna; Franchi, Matteo; Monzio Compagnoni, Matteo; Merlino, Luca; Corrao, Giovanni

2017-07-12

Maternal socioeconomic disparities strongly affect child health, particularly in low and middle income countries. We assessed whether neonatal outcomes varied by maternal education in a setting where healthcare system provides universal coverage of health services to all women, irrespective of their socioeconomic status. A population-based study was performed on 383,103 singleton live births occurring from 2005 to 2010 in Lombardy, an Italian region with approximately 10 million inhabitants. The association between maternal education, birthplace and selected neonatal outcomes (preterm birth, low birth weight, small-for-gestational age, low 5-min Apgar score, severe congenital anomalies, cerebral distress and respiratory distress) was estimated by fitting logistic regression models. Model adjustments were applied for sociodemographic, reproductive and medical maternal traits. Compared with low-level educated mothers, those with high education had reduced odds of preterm birth (Odds Ratio; OR = 0.81, 95% CI 0.77-0.85), low birth weight (OR = 0.78, 95% CI 0.70-0.81), small for gestational age (OR = 0.82, 95% CI 0.79-0.85), and respiratory distress (OR = 0.84, 95% CI 0.80-0.88). Mothers born in a foreign country had higher odds of preterm birth (OR = 1.16, 95% CI 1.11-1.20), low Apgar score (OR = 1.18, 95% CI 1.07-1.30) and respiratory distress (OR = 1.19, 95% CI 1.15-1.24) than Italian-born mothers. The influence of maternal education on neonatal outcomes was confirmed among both, Italian-born and foreign-born mothers. Low levels of education and maternal birthplace are important factors associated with adverse neonatal outcomes in Italy. Future studies are encouraged to investigate factors mediating the effects of socioeconomic inequality for identifying the main target groups for interventions.

Effects of Nativity, Length of Residence, and County-Level Foreign-Born Density on Mental Health Among Older Adults in the U.S

PubMed Central

Choi, Sunha; Kim, Giyeon

2016-01-01

Using the 2004–2007 Medical Expenditure Panel Survey data that are linked to county-level data from the Area Health Resources Files, this study examined whether the healthy immigrant effect applies to mental health of foreign-born older adults. Additionally, testing a protective ethnic density effect on older foreign-born individuals’ mental health, this study examined how the percentage of foreign-born population in the county affected the relationship between older adults’ immigration status (U.S.-nativity and length of residence in the U.S.) and their mental health status. The sample included 29,011 individuals (level-1) from 920 counties (level-2) across 50 states and D.C. Using the Mental Component Summary of the Short-Form 12, the Kessler Index (K-6), and the Patient Health Questionnaire (PHQ-2), U.S.-born individuals (n = 24,225), earlier immigrants (≥15 years in the U.S.; n = 3866), and recent immigrants (<15 years in the U.S.; n = 920) were compared. The results indicate that recent immigrants showed worse mental health on all three measures compared with U.S.-born individuals and on the K-6 and PHQ-2 compared with earlier immigrants. Higher county-level foreign-born densities were associated with worse mental health status of individuals. However, the significant interactions found in the full conditional multilevel models indicated that the high foreign-born density functioned as a risk factor for worse mental health only among recent immigrants but not among the U.S.-born. In conclusion, the results revealed the vulnerability of older recent immigrants, especially those living in the counties with high foreign-born densities. PMID:26910461

Effects of Nativity, Length of Residence, and County-Level Foreign-Born Density on Mental Health Among Older Adults in the U.S.

PubMed

Choi, Sunha; Kim, Giyeon; Lee, Sungkyu

2016-12-01

Using the 2004-2007 Medical Expenditure Panel Survey data that are linked to county-level data from the Area Health Resources Files, this study examined whether the healthy immigrant effect applies to mental health of foreign-born older adults. Additionally, testing a protective ethnic density effect on older foreign-born individuals' mental health, this study examined how the percentage of foreign-born population in the county affected the relationship between older adults' immigration status (U.S.-nativity and length of residence in the U.S.) and their mental health status. The sample included 29,011 individuals (level-1) from 920 counties (level-2) across 50 states and D.C. Using the Mental Component Summary of the Short-Form 12, the Kessler Index (K-6), and the Patient Health Questionnaire (PHQ-2), U.S.-born individuals (n = 24,225), earlier immigrants (≥15 years in the U.S.; n = 3866), and recent immigrants (<15 years in the U.S.; n = 920) were compared. The results indicate that recent immigrants showed worse mental health on all three measures compared with U.S.-born individuals and on the K-6 and PHQ-2 compared with earlier immigrants. Higher county-level foreign-born densities were associated with worse mental health status of individuals. However, the significant interactions found in the full conditional multilevel models indicated that the high foreign-born density functioned as a risk factor for worse mental health only among recent immigrants but not among the U.S.-born. In conclusion, the results revealed the vulnerability of older recent immigrants, especially those living in the counties with high foreign-born densities.

Improvements in mode-based waveform modeling and application to Eurasian velocity structure

NASA Astrophysics Data System (ADS)

Panning, M. P.; Marone, F.; Kim, A.; Capdeville, Y.; Cupillard, P.; Gung, Y.; Romanowicz, B.

2006-12-01

We introduce several recent improvements to mode-based 3D and asymptotic waveform modeling and examine how to integrate them with numerical approaches for an improved model of upper-mantle structure under eastern Eurasia. The first step in our approach is to create a large-scale starting model including shear anisotropy using Nonlinear Asymptotic Coupling Theory (NACT; Li and Romanowicz, 1995), which models the 2D sensitivity of the waveform to the great-circle path between source and receiver. We have recently improved this approach by implementing new crustal corrections which include a non-linear correction for the difference between the average structure of several large regions from the global model with further linear corrections to account for the local structure along the path between source and receiver (Marone and Romanowicz, 2006; Panning and Romanowicz, 2006). This model is further refined using a 3D implementation of Born scattering (Capdeville, 2005). We have made several recent improvements to this method, in particular introducing the ability to represent perturbations to discontinuities. While the approach treats all sensitivity as linear perturbations to the waveform, we have also experimented with a non-linear modification analogous to that used in the development of NACT. This allows us to treat large accumulated phase delays determined from a path-average approximation non-linearly, while still using the full 3D sensitivity of the Born approximation. Further refinement of shallow regions of the model is obtained using broadband forward finite-difference waveform modeling. We are also integrating a regional Spectral Element Method code into our tomographic modeling, allowing us to move beyond many assumptions inherent in the analytic mode-based approaches, while still taking advantage of their computational efficiency. Illustrations of the effects of these increasingly sophisticated steps will be presented.

Risk factors for kid mortality in West African Dwarf goats under an intensive management system in Ghana.

PubMed

Turkson, P K; Antiri, Y K; Baffuor-Awuah, O

2004-05-01

Breeding records from 1997 to 2000 for West African Dwarf goats kept under an intensive management system on the National Breeding Station at Kintampo in Ghana were analysed for the effect on mortality of sex, season and type of birth, and birth weight. The pre-weaning and post-weaning mortalities were 10% (n = 390) and 23.1% (n = 351), respectively, while the overall mortality from birth up to 12 months of age was 30.8% (n = 390). The post-weaning period recorded significantly higher proportions of deaths in males, females, single-born and twins, during the rainy and dry seasons, and for kids with low or high birth weight, compared to the pre-weaning period. There was significantly higher mortality in male kids than in female kids. The odds and risks of death for male kids were about twice those for females at post-weaning and up to 1 year of age. At pre-weaning and up to 1 year of age, a higher proportion of the dead were twins. Twins had approximately 2.5 the risk of death at pre-weaning, compared to singles. Also, kids born in the rainy season had significantly higher mortality than those born in the dry season. Kids that died by the time of weaning were significantly lighter in weight at birth than those that survived. Male kids had significantly higher mean weights at birth and at weaning, but not at 12 months of age. The significance of these findings is discussed.

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.

Excitation of levels in Li6 by inelastic electron scattering

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

Bernheim, M.; Bishop, G. R.

1963-07-01

Inelastic scattering of electrons from metallic targets of Li 6 was studied as part of a program to establish the validity of the Born approximation calculation of the cross section. This calculation predicts the separation of the inelastic form factor into two contributions corresponding to the absorption of longitudinal and transverse virtual photons by the bombarded system. (R.E.U.)

Parametrization of electron impact ionization cross sections for CO, CO2, NH3 and SO2

NASA Technical Reports Server (NTRS)

Srivastava, Santosh K.; Nguyen, Hung P.

1987-01-01

The electron impact ionization and dissociative ionization cross section data of CO, CO2, CH4, NH3, and SO2, measured in the laboratory, were parameterized utilizing an empirical formula based on the Born approximation. For this purpose an chi squared minimization technique was employed which provided an excellent fit to the experimental data.

Theoretical and experimental quantification of doubly and singly differential cross sections for electron-induced ionization of isolated tetrahydrofuran molecules

DOE PAGES

Champion, Christophe; Quinto, Michele A.; Bug, Marion U.; ...

2014-07-29

Electron-induced ionization of the commonly used surrogate of the DNA sugar-phosphate backbone, namely, the tetrahydrofuran molecule, is here theoretically described within the 1 st Born approximation by means of quantum-mechanical approach. Comparisons between theory and recent experiments are reported in terms of doubly and singly differential cross sections.

Reprint of: Ionization probabilities of Ne, Ar, Kr, and Xe by proton impact for different initial states and impact energies

NASA Astrophysics Data System (ADS)

Montanari, C. C.; Miraglia, J. E.

2018-01-01

In this contribution we present ab initio results for ionization total cross sections, probabilities at zero impact parameter, and impact parameter moments of order +1 and -1 of Ne, Ar, Kr, and Xe by proton impact in an extended energy range from 100 keV up to 10 MeV. The calculations were performed by using the continuum distorted wave eikonal initial state approximation (CDW-EIS) for energies up to 1 MeV, and using the first Born approximation for larger energies. The convergence of the CDW-EIS to the first Born above 1 MeV is clear in the present results. Our inner-shell ionization cross sections are compared with the available experimental data and with the ECPSSR results. We also include in this contribution the values of the ionization probabilities at the origin, and the impact parameter dependence. These values have been employed in multiple ionization calculations showing very good description of the experimental data. Tables of the ionization probabilities are presented, disaggregated for the different initial bound states, considering all the shells for Ne and Ar, the M-N shells of Kr and the N-O shells of Xe.

Role of the 3He optical model potential ambiguity in the distorted-wave Born approximation description of the 58Ni(3He, d)59Cu reaction at 130 MeV incident energy

NASA Astrophysics Data System (ADS)

Djaloeis, A.; Alderliesten, C.; Bojowald, J.; Mayer-Böricke, C.; Oelert, W.; Turek, P.

1983-04-01

Angular distributions of 58Ni(3He, d)59Cu transitions leading to the (0.0 MeV, 32-), (0.91 MeV, 52-), and (3.04 MeV, 92+) states in 59Cu have been measured at an incident energy of 130 MeV. The experimental data have been used to study mainly the role of the 3He optical model potential ambiguity in the distorted-wave Born approximation description of the reaction. Satisfactory fits to the data are obtained using a deep helion potential in standard local zero-range calculations. For a shallow 3He potential a comparable description can be achieved if the depth of the real part of the deuteron optical potential is reduced considerably, and nonlocality as well as finite-range corrections are taken into account. Under these conditions, the use of a 3He potential constructed according to the Johnson-Soper prescription yields similar results. NUCLEAR REACTIONS 58Ni (3He, d)59Cu, E=130 MeV; measured dσ(θ)dΩ. Enriched target; DWBA analysis; discussed reaction mechanism.

Cavity Born-Oppenheimer Approximation for Correlated Electron-Nuclear-Photon Systems.

PubMed

Flick, Johannes; Appel, Heiko; Ruggenthaler, Michael; Rubio, Angel

2017-04-11

In this work, we illustrate the recently introduced concept of the cavity Born-Oppenheimer approximation [ Flick et al. PNAS 2017 , 10.1073/pnas.1615509114 ] for correlated electron-nuclear-photon problems in detail. We demonstrate how an expansion in terms of conditional electronic and photon-nuclear wave functions accurately describes eigenstates of strongly correlated light-matter systems. For a GaAs quantum ring model in resonance with a photon mode we highlight how the ground-state electronic potential-energy surface changes the usual harmonic potential of the free photon mode to a dressed mode with a double-well structure. This change is accompanied by a splitting of the electronic ground-state density. For a model where the photon mode is in resonance with a vibrational transition, we observe in the excited-state electronic potential-energy surface a splitting from a single minimum to a double minimum. Furthermore, for a time-dependent setup, we show how the dynamics in correlated light-matter systems can be understood in terms of population transfer between potential energy surfaces. This work at the interface of quantum chemistry and quantum optics paves the way for the full ab initio description of matter-photon systems.

Language functions in preterm-born children: a systematic review and meta-analysis.

PubMed

van Noort-van der Spek, Inge L; Franken, Marie-Christine J P; Weisglas-Kuperus, Nynke

2012-04-01

Preterm-born children (<37 weeks' gestation) have higher rates of language function problems compared with term-born children. It is unknown whether these problems decrease, deteriorate, or remain stable over time. The goal of this research was to determine the developmental course of language functions in preterm-born children from 3 to 12 years of age. Computerized databases Embase, PubMed, Web of Knowledge, and PsycInfo were searched for studies published between January 1995 and March 2011 reporting language functions in preterm-born children. Outcome measures were simple language function assessed by using the Peabody Picture Vocabulary Test and complex language function assessed by using the Clinical Evaluation of Language Fundamentals. Pooled effect sizes (in terms of Cohen's d) and 95% confidence intervals (CI) for simple and complex language functions were calculated by using random-effects models. Meta-regression was conducted with mean difference of effect size as the outcome variable and assessment age as the explanatory variable. Preterm-born children scored significantly lower compared with term-born children on simple (d = -0.45 [95% CI: -0.59 to -0.30]; P < .001) and on complex (d = -0.62 [95% CI: -0.82 to -0.43]; P < .001) language function tests, even in the absence of major disabilities and independent of social economic status. For complex language function (but not for simple language function), group differences between preterm- and term-born children increased significantly from 3 to 12 years of age (slope = -0.05; P = .03). While growing up, preterm-born children have increasing difficulties with complex language function.

Scaling Cross Sections for Ion-atom Impact Ionization

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

Igor D. Kaganovich; Edward Startsev; Ronald C. Davidson

2003-06-06

The values of ion-atom ionization cross sections are frequently needed for many applications that utilize the propagation of fast ions through matter. When experimental data and theoretical calculations are not available, approximate formulas are frequently used. This paper briefly summarizes the most important theoretical results and approaches to cross section calculations in order to place the discussion in historical perspective and offer a concise introduction to the topic. Based on experimental data and theoretical predictions, a new fit for ionization cross sections is proposed. The range of validity and accuracy of several frequently used approximations (classical trajectory, the Born approximation,more » and so forth) are discussed using, as examples, the ionization cross sections of hydrogen and helium atoms by various fully stripped ions.« less

Estimating the impact of newly arrived foreign-born persons on tuberculosis in the United States.

PubMed

Liu, Yecai; Painter, John A; Posey, Drew L; Cain, Kevin P; Weinberg, Michelle S; Maloney, Susan A; Ortega, Luis S; Cetron, Martin S

2012-01-01

Among approximately 163.5 million foreign-born persons admitted to the United States annually, only 500,000 immigrants and refugees are required to undergo overseas tuberculosis (TB) screening. It is unclear what extent of the unscreened nonimmigrant visitors contributes to the burden of foreign-born TB in the United States. We defined foreign-born persons within 1 year after arrival in the United States as "newly arrived", and utilized data from U.S. Department of Homeland Security, U.S. Centers for Disease Control and Prevention, and World Health Organization to estimate the incidence of TB among newly arrived foreign-born persons in the United States. During 2001 through 2008, 11,500 TB incident cases, including 291 multidrug-resistant TB incident cases, were estimated to occur among 20,989,738 person-years for the 1,479,542,654 newly arrived foreign-born persons in the United States. Of the 11,500 estimated TB incident cases, 41.6% (4,783) occurred among immigrants and refugees, 36.6% (4,211) among students/exchange visitors and temporary workers, 13.8% (1,589) among tourists and business travelers, and 7.3% (834) among Canadian and Mexican nonimmigrant visitors without an I-94 form (e.g., arrival-departure record). The top 3 newly arrived foreign-born populations with the largest estimated TB incident cases per 100,000 admissions were immigrants and refugees from high-incidence countries (e.g., 2008 WHO-estimated TB incidence rate of ≥100 cases/100,000 population/year; 235.8 cases/100,000 admissions, 95% confidence interval [CI], 228.3 to 243.3), students/exchange visitors and temporary workers from high-incidence countries (60.9 cases/100,000 admissions, 95% CI, 58.5 to 63.3), and immigrants and refugees from medium-incidence countries (e.g., 2008 WHO-estimated TB incidence rate of 15-99 cases/100,000 population/year; 55.2 cases/100,000 admissions, 95% CI, 51.6 to 58.8). Newly arrived nonimmigrant visitors contribute substantially to the burden of foreign-born TB in the United States. To achieve the goals of TB elimination, direct investment in global TB control and strategies to target nonimmigrant visitors should be considered.

Cardiovascular Disease Risk Factor Profiles of 263,356 Older Australians According to Region of Birth and Acculturation, with a Focus on Migrants Born in Asia

PubMed Central

Guo, Shuyu; Lucas, Robyn M.; Joshy, Grace; Banks, Emily

2015-01-01

Risk factors for cardiovascular disease (CVD), such as obesity, diabetes, hypertension and physical inactivity, are common in Australia, but the prevalence varies according to cultural background. We examined the relationship between region of birth, measures of acculturation, and CVD risk profiles in immigrant, compared to Australian-born, older Australians. Cross-sectional data from 263,356 participants aged 45 and over joining the population-based 45 and Up Study cohort from 2006–2008 were used. Prevalence ratios for CVD risk factors in Australian- versus overseas-born participants were calculated using modified Poisson regression, adjusting for age, sex and socioeconomic factors and focusing on Asian migrants. The association between time resident in Australia and age at migration and CVD risk factors in Asian migrants was also examined. Migrants from Northeast (n = 3,213) and Southeast Asia (n = 3,942) had lower levels of overweight/obesity, physical activity and female smoking than Australian-born participants (n = 199,356), although differences in prevalence of overweight/obesity were sensitive to body-mass-index cut-offs used. Compared to Australian-born participants, migrants from Northeast Asia were 20–30% less likely, and from Southeast Asia 10–20% more likely, to report being treated for hypertension and/or hypercholesterolaemia; Southeast Asian migrants were 40–60% more likely to report diabetes. Northeast Asian-born individuals were less likely than Australian-born to have 3 or more CVD risk factors. Diabetes, treated hypertension and hypercholesterolaemia occurred at relatively low average body-mass-index in Southeast Asian migrants. The CVD risk factor profiles of migrants tended to approximate those of Australian-born with increasing acculturation, in both favourable (e.g., increased physical activity) and unfavourable directions (e.g., increased female smoking). Minimizing CVD risk in migrant populations may be achieved through efforts to retain the healthy facets of the traditional lifestyle, such as a normal body mass index and low prevalence of smoking in women, in addition to adopting healthy aspects of the host country lifestyle, such as increased physical activity. PMID:25695771

Agreement of Experiment and Theory on the Single Ionization of Helium by Fast Proton Impact.

PubMed

Gassert, H; Chuluunbaatar, O; Waitz, M; Trinter, F; Kim, H-K; Bauer, T; Laucke, A; Müller, Ch; Voigtsberger, J; Weller, M; Rist, J; Pitzer, M; Zeller, S; Jahnke, T; Schmidt, L Ph H; Williams, J B; Zaytsev, S A; Bulychev, A A; Kouzakov, K A; Schmidt-Böcking, H; Dörner, R; Popov, Yu V; Schöffler, M S

2016-02-19

Even though the study of ion-atom collisions is a mature field of atomic physics, large discrepancies between experiment and theoretical calculations are still common. Here we present experimental results with high momentum resolution on the single ionization of helium induced by 1-MeV protons, and we compare these to theoretical calculations. The overall agreement is strikingly good, and even the first Born approximation yields good agreement between theory and experiment. This has been expected for several decades, but so far has not been accomplished. The influence of projectile coherence effects on the measured data is briefly discussed in terms of an ongoing dispute on the existence of nodal structures in the electron angular emission distributions.

Positron scattering from pyridine

NASA Astrophysics Data System (ADS)

Stevens, D.; Babij, T. J.; Machacek, J. R.; Buckman, S. J.; Brunger, M. J.; White, R. D.; García, G.; Blanco, F.; Ellis-Gibbings, L.; Sullivan, J. P.

2018-04-01

We present a range of cross section measurements for the low-energy scattering of positrons from pyridine, for incident positron energies of less than 20 eV, as well as the independent atom model with the screening corrected additivity rule including interference effects calculation, of positron scattering from pyridine, with dipole rotational excitations accounted for using the Born approximation. Comparisons are made between the experimental measurements and theoretical calculations. For the positronium formation cross section, we also compare with results from a recent empirical model. In general, quite good agreement is seen between the calculations and measurements although some discrepancies remain which may require further investigation. It is hoped that the present study will stimulate development of ab initio level theoretical methods to be applied to this important scattering system.

Caring for the infant of a diabetic mother.

PubMed

Hatfield, Linda; Schwoebel, Ann; Lynyak, Corinne

2011-01-01

In the United States, approximately 100,000 infants are born to diabetic mothers each year. If diabetes in pregnancy is uncontrolled, the diversity of resulting health problems can have a profound effect on the embryo, the fetus, and the neonate. These infants are at risk for a multitude of physiologic, metabolic, and congenital complications such as macrosomia, asphyxia, respiratory distress, hypoglycemia, hypocalcemia, hyperbilirubinemia, polycythemia and hyperviscosity, cardiomegaly, and central nervous system disruption. Preconception control of glucose metabolism throughout the trajectory of a woman's pregnancy is a significant factor in decreasing the adverse impact of diabetes on the fetus and newborn. Meticulous attention to neonatal glucose levels, thorough physical examination, and precise diagnosis are prerequisites to appropriate care for the neonate.

Tissue multifractality and hidden Markov model based integrated framework for optimum precancer detection

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Sabyasachi; Das, Nandan K.; Kurmi, Indrajit; Pradhan, Asima; Ghosh, Nirmalya; Panigrahi, Prasanta K.

2017-10-01

We report the application of a hidden Markov model (HMM) on multifractal tissue optical properties derived via the Born approximation-based inverse light scattering method for effective discrimination of precancerous human cervical tissue sites from the normal ones. Two global fractal parameters, generalized Hurst exponent and the corresponding singularity spectrum width, computed by multifractal detrended fluctuation analysis (MFDFA), are used here as potential biomarkers. We develop a methodology that makes use of these multifractal parameters by integrating with different statistical classifiers like the HMM and support vector machine (SVM). It is shown that the MFDFA-HMM integrated model achieves significantly better discrimination between normal and different grades of cancer as compared to the MFDFA-SVM integrated model.

Elastic, inelastic, and 1 n transfer cross sections for the 10B+120Sn reaction

NASA Astrophysics Data System (ADS)

Gasques, L. R.; Freitas, A. S.; Chamon, L. C.; Oliveira, J. R. B.; Medina, N. H.; Scarduelli, V.; Rossi, E. S.; Alvarez, M. A. G.; Zagatto, V. A. B.; Lubian, J.; Nobre, G. P. A.; Padron, I.; Carlson, B. V.

2018-03-01

The 10B+120Sn reaction has been investigated at ELab=37.5 MeV. The cross sections for different channels, such as the elastic scattering, the excitation of the 2+ and 3-120Sn states, the excitation of the 1+ state of 10B, and the 1 n pick-up transfer, have been measured. One-step distorted-wave Born approximation and coupled-reaction-channels calculations have been performed in the context of the double-folding São Paulo potential. The effect of coupling the inelastic and transfer states on the angular distributions is discussed in the paper. In general, the theoretical calculations within the coupled-reaction-channels formalism yield a satisfactory agreement with the corresponding experimental angular distributions.

Gate-controlled current and inelastic electron tunneling spectrum of benzene: a self-consistent study.

PubMed

Liang, Y Y; Chen, H; Mizuseki, H; Kawazoe, Y

2011-04-14

We use density functional theory based nonequilibrium Green's function to self-consistently study the current through the 1,4-benzenedithiol (BDT). The elastic and inelastic tunneling properties through this Au-BDT-Au molecular junction are simulated, respectively. For the elastic tunneling case, it is found that the current through the tilted molecule can be modulated effectively by the external gate field, which is perpendicular to the phenyl ring. The gate voltage amplification comes from the modulation of the interaction between the electrodes and the molecules in the junctions. For the inelastic case, the electron tunneling scattered by the molecular vibrational modes is considered within the self-consistent Born approximation scheme, and the inelastic electron tunneling spectrum is calculated.

Effects of dynamical screening on single ionization of potassium by electron impact in doubly symmetric geometry

NASA Astrophysics Data System (ADS)

Sun, S. Y.; Jia, X. F.; Miao, X. Y.; Zhang, J. F.

2014-03-01

The dynamically screened three-Coulomb-wave (DS3C) method is applied to study the single ionization of potassium by electron impact. Triple differential cross-sections (TDCS) are calculated in doubly symmetric geometry at excess energies of 6, 10, 15, 20, 30, 40, 50 and 60 eV. Comparisons are made with recent experimental data and theoretical predictions from a three-Coulomb-wave (3C) and distorted-wave Born approximation (DWBA). The DS3C method is able to reproduce most of the trend of experimental data and in good agreement with DWBA results. It is shown that the DS3C calculation provides much better shape and relative magnitude agreement with experiment.

Cross sections and rate coefficients for excitation of Δn = 1 transitions in Li-like ions with 6 < Z < 42.

NASA Astrophysics Data System (ADS)

Safronova, U. I.; Safronova, M. S.; Kato, T.

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 XXXIIV and Mo XXXX) by a Coulomb-Born approximation with exchange and including relativistic effects and configuration interactions. Level energies, mixing coefficients and transition wavelengths and probabilities were also computed.

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.

Birth order effects on autism symptom domains.

PubMed

Reichenberg, Abraham; Smith, Christopher; Schmeidler, James; Silverman, Jeremy M

2007-03-30

Autism is predominantly genetically determined. Evidence supports familiality of the main sets of behavioral characteristics that define the syndrome of autism; however, possible non-genetic effects have also been suggested. The present study compared levels of autism symptom domains, as measured by the Autism Diagnostic Interview, and useful phrase speech scores between 106 pairs of first- and second-born siblings from multiply affected families. In addition, the intercorrelations between the measures were compared between siblings. The overall mean repetitive behavior total score was significantly higher (worse) in first-born than in second-born siblings. In contrast, first-born siblings had significantly lower (better) useful phrase speech than their younger siblings. Autism social and non-verbal communication scores were significantly correlated in first- and in second-born siblings. However, there was a significant difference in the coefficients between first- and second-born siblings. Performance on the non-verbal communication domain was also significantly and positively correlated with useful phrase speech score in both first- and second-born siblings. It is unclear at this time whether these results are of biologic origin. Nevertheless, the findings suggest that genetic studies in autism using specific levels of familial autism traits as phenotypes should take into account their intercorrelations and birth order effects embedded in the instrument.

Economic trade-offs between genetic improvement and longevity in dairy cattle.

PubMed

De Vries, A

2017-05-01

Genetic improvement in sires used for artificial insemination (AI) is increasing faster compared with a decade ago. The genetic merit of replacement heifers is also increasing faster and the genetic lag with older cows in the herd increases. This may trigger greater cow culling to capture this genetic improvement. On the other hand, lower culling rates are often viewed favorably because the costs and environmental effects of maintaining herd size are generally lower. Thus, there is an economic trade-off between genetic improvement and longevity in dairy cattle. The objective of this study was to investigate the principles, literature, and magnitude of these trade-offs. Data from the Council on Dairy Cattle Breeding show that the estimated breeding value of the trait productive life has increased for 50 yr but the actual time cows spend in the herd has not increased. The average annual herd cull rate remains at approximately 36% and cow longevity is approximately 59 mo. The annual increase in average estimated breeding value of the economic index lifetime net merit of Holstein sires is accelerating from $40/yr when the sire entered AI around 2002 to $171/yr for sires that entered AI around 2012. The expectation is therefore that heifers born in 2015 are approximately $50 more profitable per lactation than heifers born in 2014. Asset replacement theory shows that assets should be replaced sooner when the challenging asset is technically improved. Few studies have investigated the direct effects of genetic improvement on optimal cull rates. A 35-yr-old study found that the economically optimal cull rates were in the range of 25 to 27%, compared with the lowest possible involuntary cull rate of 20%. Only a small effect was observed of using the best surviving dams to generate the replacement heifer calves. Genetic improvement from sires had little effect on the optimal cull rate. Another study that optimized culling decisions for individual cows also showed that the effect of changes in genetic improvement of milk revenue minus feed cost on herd longevity was relatively small. Reduced involuntary cull rates improved profitability, but also increased optimal voluntary culling. Finally, an economically optimal culling model with prices from 2015 confirmed that optimal annual cull rates were insensitive to heifer prices and therefore insensitive to genetic improvement in heifers. In conclusion, genetic improvement is important but does not warrant short cow longevity. Economic cow longevity continues to depends more on cow depreciation than on accelerated genetic improvements in heifers. This is confirmed by old and new studies. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

[Study on national active monitoring for food borne pathogens and antimicrobial resistance in China 2001].

PubMed

Wang, Maoqi; Ran, Lu; Wang, Zhutian; Li, Zhigang

2004-01-01

To survey food borne pathogens and antimicrobial resistance in China. A total of 4034 samples of foods (raw meats, raw milk, cooked meats, ice cream, yoghurt, aquatic product and vegetable) were examined for the presence of Escherichia coli O157:H7 Salmonella spp and Listeria monocytogens by national active foodborne pathogens surveillance system. The samples were obtained from 11 provinces in 2001. Approximate 5.50% of the all samples yielded 3 pathogenes, whereas Escherichia coli O157:H7 (0.82%), Salmonella servoars (3.32%) and Listeria monocytogens (1.29%). The most heavy contamination by three food borne pathogens are in raw meat (12.96%). Top seven serotype of the 137 Salmonella isolates are S. derby, S. agona, S. enteritidis, S. reading, S. anatum. S. muenster, S. typhimurium. Serotypes and antibiotic resistance patterns of Salmonella isolates are different in 11 provinces. E. coli O157:H7 strains that are isolated from raw meat and cooked meat have VT2, eae, Hly genes. Salmonella and E. coli strains of multidrug resistance were isolated and identified.

Persistent and progressive long-term lung disease in survivors of preterm birth.

PubMed

Urs, Rhea; Kotecha, Sailesh; Hall, Graham L; Simpson, Shannon J

2018-04-13

Preterm birth accounts for approximately 11% of births globally, with rates increasing across many countries. Concurrent advances in neonatal care have led to increased survival of infants of lower gestational age (GA). However, infants born <32 weeks of GA experience adverse respiratory outcomes, manifesting with increased respiratory symptoms, hospitalisation and health care utilisation into early childhood. The development of bronchopulmonary dysplasia (BPD) - the chronic lung disease of prematurity - further increases the risk of poor respiratory outcomes throughout childhood, into adolescence and adulthood. Indeed, survivors of preterm birth have shown increased respiratory symptoms, altered lung structure, persistent and even declining lung function throughout childhood. The mechanisms behind this persistent and sometimes progressive lung disease are unclear, and the implications place those born preterm at increased risk of respiratory morbidity into adulthood. This review aims to summarise what is known about the long-term pulmonary outcomes of contemporary preterm birth, examine the possible mechanisms of long-term respiratory morbidity in those born preterm and discuss addressing the unknowns and potentials for targeted treatments. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mental Health of Aging Immigrants and Native-Born Men Across 11 European Countries

PubMed Central

2013-01-01

Objectives. Though working-age immigrants exhibit lower mortality compared with those domestic-born immigrants, consequences of immigration for mental health remain unclear. We examine whether older immigrants exhibit a mental advantage and whether factors believed to underlie immigrant vulnerability explain disparities. Method. The sample includes 12,247 noninstitutionalized men more than 50 years in 11 European countries. Multivariate logistic regression models estimated the impact of physical health, health behaviors, availability of social support, social participation, citizenship, time since immigration, socioeconomic status (SES), and employment on the mental health of immigrants. Results. Immigrants face 1.60 increased odds of depression despite a physical health advantage, evidenced by 0.74 lower odds of chronic illness. SES and availability of social support were predictive, though acculturation measures were not. Decomposition analysis revealed that only approximately 20% of the variation in depression rates between immigrants and native-born peers were explained by commonly cited risk factors. Conclusions. Despite physical health advantages, older immigrants suffer substantially higher depression rates. Time since immigration does not appear to mitigate depressive symptoms. PMID:23325505

Chronic treatment with AMPA receptor potentiator Org 26576 increases neuronal cell proliferation and survival in adult rodent hippocampus.

PubMed

Su, Xiaowei W; Li, Xiao-Yuan; Banasr, Mounira; Koo, Ja Wook; Shahid, Mohammed; Henry, Brian; Duman, Ronald S

2009-10-01

Currently available antidepressants upregulate hippocampal neurogenesis and prefrontal gliogenesis after chronic administration, which could block or reverse the effects of stress. Allosteric alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor potentiators (ARPs), which have novel targets compared to current antidepressants, have been shown to have antidepressant properties in neurogenic and behavioral models. This study analyzed the effect of the ARP Org 26576 on the proliferation, survival, and differentiation of neurons and glia in the hippocampus and prelimbic cortex of adult rats. Male Sprague-Dawley rats received acute (single day) or chronic (21 day) twice-daily intraperitoneal injections of Org 26576 (1-10 mg/kg). Bromodeoxyuridine (BrdU) immunohistochemistry was conducted 24 h or 28 days after the last drug injection for the analysis of cell proliferation or survival, respectively. Confocal immunofluorescence analysis was used to determine the phenotype of surviving cells. Acute administration of Org 26576 did not increase neuronal cell proliferation. However, chronic administration of Org 26576 increased progenitor cell proliferation in dentate gyrus (approximately 40%) and in prelimbic cortex (approximately 35%) at the 10-mg/kg dosage. Cells born in response to chronic Org 26576 in dentate gyrus exhibited increased rates of survival (approximately 30%) with the majority of surviving cells expressing a neuronal phenotype. Findings suggest that Org 26576 may have antidepressant properties, which may be attributed, in part, to upregulation of hippocampal neurogenesis and prelimbic cell proliferation.

Costs of Food Safety Investments in the Meat and Poultry Slaughter Industries.

PubMed

Viator, Catherine L; Muth, Mary K; Brophy, Jenna E; Noyes, Gary

2017-02-01

To develop regulations efficiently, federal agencies need to know the costs of implementing various regulatory alternatives. As the regulatory agency responsible for the safety of meat and poultry products, the U.S. Dept. of Agriculture's Food Safety and Inspection Service is interested in the costs borne by meat and poultry establishments. This study estimated the costs of developing, validating, and reassessing hazard analysis and critical control points (HACCP), sanitary standard operating procedures (SSOP), and sampling plans; food safety training for new employees; antimicrobial equipment and solutions; sanitizing equipment; third-party audits; and microbial tests. Using results from an in-person expert consultation, web searches, and contacts with vendors, we estimated capital equipment, labor, materials, and other costs associated with these investments. Results are presented by establishment size (small and large) and species (beef, pork, chicken, and turkey), when applicable. For example, the cost of developing food safety plans, such as HACCP, SSOP, and sampling plans, can range from approximately $6000 to $87000, depending on the type of plan and establishment size. Food safety training costs from approximately $120 to $2500 per employee, depending on the course and type of employee. The costs of third-party audits range from approximately $13000 to $24000 per audit, and establishments are often subject to multiple audits per year. Knowing the cost of these investments will allow researchers and regulators to better assess the effects of food safety regulations and evaluate cost-effective alternatives. © 2017 Institute of Food Technologists®.

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

ANALYSIS OF DEUTERON STRIPPING EXPERIMENTS

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

Amado, R.D.

1959-05-01

Deuteron stripping experiments analyzed according to the theory of Butter are a nearly unique source of information on the orbital angular momentum and single-particle widths of nuclear bound states. A number of problems in the Butter theory remain. Chew and Low show that in reactions in which there is a contribution from thc exchange of a single particles there can appear isolated poles in the normalized Born approximation to the cross section and that the residue at these poles can be related to quantities of physical interest. Stripping is such a reactions and the Butter theory is the renormalized Bornmore » approximation. (A.C.)« less

Quantum gravitational contributions to the cosmic microwave background anisotropy spectrum.

PubMed

Kiefer, Claus; Krämer, Manuel

2012-01-13

We derive the primordial power spectrum of density fluctuations in the framework of quantum cosmology. For this purpose we perform a Born-Oppenheimer approximation to the Wheeler-DeWitt equation for an inflationary universe with a scalar field. In this way, we first recover the scale-invariant power spectrum that is found as an approximation in the simplest inflationary models. We then obtain quantum gravitational corrections to this spectrum and discuss whether they lead to measurable signatures in the cosmic microwave background anisotropy spectrum. The nonobservation so far of such corrections translates into an upper bound on the energy scale of inflation.

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

Remote sensing of Earth terrain

NASA Technical Reports Server (NTRS)

Kong, Jin AU; Yueh, Herng-Aung

1990-01-01

The layered random medium model is used to investigate the fully polarimetric scattering of electromagnetic waves from vegetation. The vegetation canopy is modeled as an anisotropic random medium containing nonspherical scatterers with preferred alignment. The underlying medium is considered as a homogeneous half space. The scattering effect of the vegetation canopy are characterized by 3-D correlation functions with variances and correlation lengths respectively corresponding to the fluctuation strengths and the physical geometries of the scatterers. The strong fluctuation theory is used to calculate the anisotropic effective permittivity tensor of the random medium and the distorted Born approximation is then applied to obtain the covariance matrix which describes the fully polarimetric scattering properties of the vegetation field. This model accounts for all the interaction processes between the boundaries and the scatterers and includes all the coherent effects due to wave propagation in different directions such as the constructive and destructive interferences. For a vegetation canopy with low attenuation, the boundary between the vegetation and the underlying medium can give rise to significant coherent effects.

Effect of impurity resonant states on optical and thermoelectric properties on the surface of a topological insulator.

PubMed

Zhong, Min; Li, Shuai; Duan, Hou-Jian; Hu, Liang-Bin; Yang, Mou; Wang, Rui-Qiang

2017-06-21

We investigate the thermoelectric effect on a topological insulator surface with particular interest in impurity-induced resonant states. To clarify the role of the resonant states, we calculate the dc and ac conductivities and the thermoelectric coefficients along the longitudinal direction within the full Born approximation. It is found that at low temperatures, the impurity resonant state with strong energy de-pendence can lead to a zero-energy peak in the dc conductivity, whose height is sensitively dependent on the strength of scattering potential, and even can reverse the sign of the thermopower, implying the switching from n- to p-type carriers. Also, we exhibit the thermoelectric signatures for the filling process of a magnetic band gap by the resonant state. We further study the impurity effect on the dynamic optical conductivity, and find that the resonant state also generates an optical conductivity peak at the absorption edge for the interband transition. These results provide new perspectives for understanding the doping effect on topological insulator materials.

Born Oppenheimer potential energy for interaction of antihydrogen with molecular hydrogen

NASA Astrophysics Data System (ADS)

Strasburger, Krzysztof

2005-09-01

Inelastic collisions with hydrogen molecules are claimed to be an important channel of antihydrogen (\\overlineH) losses (Armour and Zeman 1999 Int. J. Quantum Chem. 74 645). In the present work, interaction energies for the H_{2}\\--\\overlineH system in the ground state have been calculated within the Born-Oppenheimer approximation. The leptonic problem was solved variationally with the basis of explicitly correlated Gaussian functions. The geometry of H2 was fixed at equilibrium geometry and the \\overlineH atom approached the molecule from two directions—along or perpendicularly to the bond axis. Purely attractive potential energy curve has been obtained for the first nuclear configuration, while a local maximum (lower than the energy at infinite separation) has been found for the second one.

Non-Born-Oppenheimer calculations of the pure vibrational spectrum of HeH+.

PubMed

Pavanello, Michele; Bubin, Sergiy; Molski, Marcin; Adamowicz, Ludwik

2005-09-08

Very accurate calculations of the pure vibrational spectrum of the HeH(+) ion are reported. The method used does not assume the Born-Oppenheimer approximation, and the motion of both the electrons and the nuclei are treated on equal footing. In such an approach the vibrational motion cannot be decoupled from the motion of electrons, and thus the pure vibrational states are calculated as the states of the system with zero total angular momentum. The wave functions of the states are expanded in terms of explicitly correlated Gaussian basis functions multipled by even powers of the internuclear distance. The calculations yielded twelve bound states and corresponding eleven transition energies. Those are compared with the pure vibrational transition energies extracted from the experimental rovibrational spectrum.

Born iterative reconstruction using perturbed-phase field estimates

PubMed Central

Astheimer, Jeffrey P.; Waag, Robert C.

2008-01-01

A method of image reconstruction from scattering measurements for use in ultrasonic imaging is presented. The method employs distorted-wave Born iteration but does not require using a forward-problem solver or solving large systems of equations. These calculations are avoided by limiting intermediate estimates of medium variations to smooth functions in which the propagated fields can be approximated by phase perturbations derived from variations in a geometric path along rays. The reconstruction itself is formed by a modification of the filtered-backpropagation formula that includes correction terms to account for propagation through an estimated background. Numerical studies that validate the method for parameter ranges of interest in medical applications are presented. The efficiency of this method offers the possibility of real-time imaging from scattering measurements. PMID:19062873

A study of the geographic coverage properties of a satellite borne Doppler lidar wind velocity measuring system

NASA Technical Reports Server (NTRS)

Pate, T. H.

1982-01-01

Geographic coverage frequency and geographic shot density for a satellite borne Doppler lidar wind velocity measuring system are measured. The equations of motion of the light path on the ground were derived and a computer program devised to compute shot density and coverage frequency by latitude-longitude sections. The equations for the coverage boundaries were derived and a computer program developed to plot these boundaries, thus making it possible, after an application of a map coloring algorithm, to actually see the areas of multiple coverage. A theoretical cross-swath shot density function that gives close approximations in certain cases was also derived. This information should aid in the design of an efficient data-processing system for the Doppler lidar.

Decomposing the Household Food Insecurity Gap for Children of U.S.-Born and Foreign-Born Hispanics: Evidence from 1998 to 2011.

PubMed

Arteaga, Irma; Potochnick, Stephanie; Parsons, Sarah

2017-10-01

Using the Early Childhood Longitudinal Study-K, multivariate analysis, state fixed effects, and regression decomposition, we examine changes in food insecurity for Hispanic kindergarteners between 1998 and 2011, a time period of rapid immigration and political/socio-economic changes. During this time the household food insecurity gap between children of U.S.-born and foreign-born mothers increased by almost 7 percentage points. The factors-child, family, and state-that contributed to the nativity gap differed over time. In both periods, lower familial resources among immigrant families, i.e. endowment effects, contributed to the gap; this was the main component of the gap in 2011 but only one component in 1998. In 1998, heterogeneity in state effects was positively associated with the nativity food insecurity gap. This means that children of foreign-born mothers experience higher household food insecurity than do children of U.S.-born mothers in the same state, even after controlling for child and family characteristics. In 2011, almost half of the gap remained unexplained. This unexplained portion could be driven by differential effects of the Great Recession, growing anti-immigrant sentiment, and/or the relatively large share of unauthorized immigrants in 2011.

The growth of railway ground vibration problems - A review.

PubMed

Connolly, David P; Marecki, Grzegorz P; Kouroussis, Georges; Thalassinakis, Ioannis; Woodward, Peter K

2016-10-15

Ground-borne noise and vibration from railway lines can cause human distress/annoyance, and also negatively affect real estate property values. Therefore this paper analyses a collection of technical ground-borne noise and vibration reports, detailing commercial vibration assessments undertaken at 1604 railway track sections, in 9 countries across the world. A wide range of rail projects are considered including light rail, tram lines, underground/tunnelled lines, freight, conventional rail and high speed rail. It documents the rise in ground-borne vibration problems and trends in the prediction industry, with the aim of informing the current research area. Firstly, the reports are analysed chronologically and it is found that railway vibration is a growing global concern, and as such, assessments have become more prevalent. International assessment metrics are benchmarked and it is found that velocity decibels (VdB), vibration dose value (VDV) and peak particle velocity (PPV) are the most commonly used methods of assessment. Furthermore, to predict vibration levels, the physical measurement of frequency transfer functions is preferential to numerical modelling. Results from the reports show that ground vibration limits are exceeded in 44% of assessments, and that ground-borne noise limits are exceeded in 31%. Moreover, mitigation measures were required on approximately 50% of projects, revealing that ground-borne noise and vibration is a widespread railroad engineering challenge. To solve these problems, the most commonly used abatement strategy is a modification of the railtrack structure (active mitigation), rather than the implementation of a more passive solution in the far-field. Copyright © 2015 Elsevier B.V. All rights reserved.

Selection, Language Heritage, and the Earnings Trajectories of Black Immigrants in the United States

PubMed Central

Hamilton, Tod G.

2014-01-01

Research suggests that immigrants from the English-speaking Caribbean surpass the earnings of U.S.-born blacks approximately one decade after arriving in the United States. Using data from the 1980–2000 U.S. censuses and the 2005–2007 American Community Surveys on U.S.-born black and non-Hispanic white men as well as black immigrant men from all the major sending regions of the world, I evaluate whether selective migration and language heritage of immigrants’ birth countries account for the documented earnings crossover. I validate the earnings pattern of black immigrants documented in previous studies, but I also find that the earnings of most arrival cohorts of immigrants from the English-speaking Caribbean, after residing in the United States for more than 20 years, are projected to converge with or slightly overtake those of U.S.-born black internal migrants. The findings also show three arrival cohorts of black immigrants from English-speaking African countries are projected to surpass the earnings of U.S.-born black internal migrants. No arrival cohort of black immigrants is projected to surpass the earnings of U.S.-born non-Hispanic whites. Birth-region analysis shows that black immigrants from English-speaking countries experience more rapid earnings growth than immigrants from non-English-speaking countries. The arrival-cohort and birth-region variation in earnings documented in this study suggest that selective migration and language heritage of black immigrants’ birth countries are important determinants of their initial earnings and earnings trajectories in the United States. PMID:24854004

Another Mexican birthweight paradox? The role of residential enclaves and neighborhood poverty in the birthweight of Mexican-origin infants.

PubMed

Osypuk, Theresa L; Bates, Lisa M; Acevedo-Garcia, Dolores

2010-02-01

Examining whether contextual factors influence the birth outcomes of Mexican-origin infants in the US may contribute to assessing rival explanations for the so-called Mexican health paradox. We examined whether birthweight among infants born to Mexican-origin women in the US was associated with Mexican residential enclaves and exposure to neighborhood poverty, and whether these associations were modified by nativity (i.e. mother's place of birth). We calculated metropolitan indices of neighborhood exposure to Mexican-origin population and poverty for the Mexican-origin population, and merged with individual-level, year 2000 natality data (n=490,332). We distinguished between neighborhood exposure to US-born Mexican-origin population (i.e. ethnic enclaves) and neighborhood exposure to foreign-born (i.e. Mexico-born) Mexican-origin population (i.e. immigrant enclaves). We used 2-level hierarchical linear regression models adjusting for individual, metropolitan, and regional covariates and stratified by nativity. We found that living in metropolitan areas with high residential segregation of US-born Mexican-origin residents (i.e. high prevalence of ethnic enclaves) was associated with lower birthweight for infants of US-born Mexican-origin mothers before and after covariate adjustment. When simultaneously adjusting for exposure to ethnic and immigrant enclaves, the latter became positively associated with birthweight and the negative effect of the former increased, among US-born mothers. We found no contextual birthweight associations for mothers born in Mexico in adjusted models. Our findings highlight a differential effect of context by nativity, and the potential health effects of ethnic enclaves, which are possibly a marker of downward assimilation, among US-born Mexican-origin women. Copyright 2009 Elsevier Ltd. All rights reserved.

Impact of Timing of Birth and Resident Duty-Hour Restrictions on Outcome of Small Preterm Infants

PubMed Central

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.

2010-01-01

OBJECTIVE 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 of VLBW infants. METHODS Outcomes were analyzed for 11,137 infants with birth weight 501–1250 grams enrolled in the NICHD Neonatal Research Network registry 2001–2005. Approximately half were born before the introduction of resident duty-hour restrictions in 2003. Follow-up assessment at 18–22 months was completed for 4,508 infants. Mortality (7-day and 28-day), short-term morbidities, and neurodevelopmental outcome were examined with respect to the timing of birth: night vs day, weekend vs weekday, and July or August vs other months, and after vs before implementation of resident duty-hour restrictions. RESULTS There was no effect of hour, day, or month of birth on mortality and no impact on the risks of short-term morbidities except the risk of ROP requiring operative treatment was lower for infants born during the late night hours than during the day. There was no impact of timing of birth on neurodevelopmental outcome except the risk of hearing impairment or death was slightly lower among infants born in July or August compared with other months. The introduction of resident and fellow duty-hour restrictions had no impact on mortality or neurodevelopmental outcome. The only change in short-term morbidity after duty-hour restrictions were introduced was an increase in the risk of ROP (stage 2 or higher). CONCLUSION In this network of academic centers, the timing of birth and the introduction of duty-hour restrictions had little effect on the risks of mortality and morbidity of VLBW infants, suggesting that staffing patterns were adequate to provide consistent care. PMID:20643715

Age of Onset of Blindness and the Development of the Semantics of Color Names.

ERIC Educational Resources Information Center

Marmor, Gloria Strauss

The relationship between age of onset of blindness and development of knowledge of color relations was examined with 16 college students who had been born totally blind, 16 who had been blinded totally at approximately 15 years of age, and 16 who had normal vision. Ss were asked to judge the similarities between color names, and judgments were…

Born in Hope and Controversy: The Challenges of Infusing Sustainability in the Campus Operations and Curriculum at Florida Gulf Coast University

ERIC Educational Resources Information Center

Wohlpart, A. James; Shepard, Joseph; Corcoran, Peter Blaze

2009-01-01

Florida Gulf Coast University, located in southwest Florida in the United States, opened its doors in 1997 with approximately 1,500 students as the tenth institution in the State University System. The site of the campus was a topic of disagreement between proponents of economic growth and development and proponents of sustainability and…

SAR Imaging through the Earth’s Ionosphere

DTIC Science & Technology

2013-11-06

or, otherwise, if polarimetry puts too high of a demand on storage, downlink capacity, etc.), then the approach based on the Faraday rotation is not...reflected fields for both are the same in the first Born approximation. Modern practical applications of radar polarimetry employ different empirical and...Fruneau, and J.-P. Rudant. Classification of tropical vegetation using multifrequency partial SAR polarimetry . IEEE Geoscience and Remote Sensing Letters

Encouraging the next generation into land-based industries.

PubMed

Rowarth, Js

2008-12-01

Members of the Y-Generation (born between approximately 1978 and 1994) have expectations of careers, rewards and 'work-life balance' that are very different from those of previous generations. This paper discusses these differences, how the land-based industries can position in order to offer 'the career path of choice', and how doing so will be of benefit not only to employers but also to New Zealand.

Generational Differences in Knowledge Markets

DTIC Science & Technology

2010-03-01

and Generation X generations. Following Generation X, Generation Y , or the Millennial Generation, includes those born between 1979 and 1994. The...positions but their numbers are small—approximately half the Baby Boomer population—and they’ll be leading Generation Y which is three times their size...boom” resulted in the 98.8 million-strong Generation Y (Sincavage, 2004). The resulting unevenness of the population distribution by age in the

Genetic evaluation of weaning weight and probability of lambing at 1 year of age in Targhee lambs

USDA-ARS?s Scientific Manuscript database

The objective of this study was to investigate genetic control of 120-day weaning weight and the probability of lambing at 1 year of age in Targhee ewe lambs. Records of 5,967 ewe lambs born from 1989 to 2012 and first exposed to rams for breeding at approximately 7 months of age were analyzed. Reco...

Racial Gaps in Early Childhood: Socio-Emotional Health, Developmental, and Educational Outcomes among African-American Boys. Report

ERIC Educational Resources Information Center

Aratani, Yumiko; Wight, Vanessa R.; Cooper, Janice L.

2011-01-01

This study uses the Early Childhood Longitudinal Study-Birth Cohort (child-B) data, collected by the National Center for Education Statistics in the U.S. Department of Education. The EC LS-B is a nationally representative longitudinal study of approximately 11,000 children who were born in 2001. The children in the EC LS-B have been followed…

Pleural mesothelioma and lung cancer risks in relation to occupational history and asbestos lung burden.

PubMed

Gilham, Clare; Rake, Christine; Burdett, Garry; Nicholson, Andrew G; Davison, Leslie; Franchini, Angelo; Carpenter, James; Hodgson, John; Darnton, Andrew; Peto, Julian

2016-05-01

We have conducted a population-based study of pleural mesothelioma patients with occupational histories and measured asbestos lung burdens in occupationally exposed workers and in the general population. The relationship between lung burden and risk, particularly at environmental exposure levels, will enable future mesothelioma rates in people born after 1965 who never installed asbestos to be predicted from their asbestos lung burdens. Following personal interview asbestos fibres longer than 5 µm were counted by transmission electron microscopy in lung samples obtained from 133 patients with mesothelioma and 262 patients with lung cancer. ORs for mesothelioma were converted to lifetime risks. Lifetime mesothelioma risk is approximately 0.02% per 1000 amphibole fibres per gram of dry lung tissue over a more than 100-fold range, from 1 to 4 in the most heavily exposed building workers to less than 1 in 500 in most of the population. The asbestos fibres counted were amosite (75%), crocidolite (18%), other amphiboles (5%) and chrysotile (2%). The approximate linearity of the dose-response together with lung burden measurements in younger people will provide reasonably reliable predictions of future mesothelioma rates in those born since 1965 whose risks cannot yet be seen in national rates. Burdens in those born more recently will indicate the continuing occupational and environmental hazards under current asbestos control regulations. Our results confirm the major contribution of amosite to UK mesothelioma incidence and the substantial contribution of non-occupational exposure, particularly in women. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Born scattering of long-period body waves

NASA Astrophysics Data System (ADS)

Dalkolmo, Jörg; Friederich, Wolfgang

2000-09-01

The Born approximation is applied to the modelling of the propagation of deeply turning long-period body waves through heterogeneities in the lowermost mantle. We use an exact Green's function for a spherically symmetric earth model that also satisfies the appropriate boundary conditions at internal boundaries and the surface of the earth. The scattered displacement field is obtained by a numerical quadrature of the product of the Green's function, the exciting wavefield and structural perturbations. We study three examples: scattering of long-period P waves from a plume rising from the core-mantle boundary (CMB), generation of long-period precursors to PKIKP by strong, localized scatterers at the CMB, and propagation of core-diffracted P waves through large-scale heterogeneities in D''. The main results are as follows: (1) the signals scattered from a realistic plume are small with relative amplitudes of less than 2 per cent at a period of 20s, rendering plume detection a fairly difficult task; (2) strong heterogeneities at the CMB of appropriate size may produce observable long-period precursors to PKIKP in spite of the presence of a diffraction from the PKP-B caustic; (3) core-diffracted P waves (Pdiff) are sensitive to structure in D'' far off the geometrical ray path and also far beyond the entry and exit points of the ray into and out of D'' sensitivity kernels exhibit ring-shaped patterns of alternating sign reminiscent of Fresnel zones; (4) Pdiff also shows a non-negligible sensitivity to shear wave velocity in D'' (5) down to periods of 40s, the Born approximation is sufficiently accurate to allow waveform modelling of Pdiff through large-scale heterogeneities in D'' of up to 5 per cent.

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.

Epidemiology of lyme borreliosis.

PubMed

Hubálek, Zdenek

2009-01-01

Lyme borreliosis (LB) is the most frequent ixodid tick-borne human disease in the world, with an estimated 85,500 patients annually (underlying data presented in this review: Europe 65,500, North America 16,500, Asia 3,500, North Africa 10; approximate figures). This chapter summarizes the up-to-date knowledge about facts and factors important in the epidemiology of LB all over the world. Individual sections briefly describe geographic (latitudinal and altitudinal) distribution and incidence rates of LB in individual countries; seasonal distribution of the disease; effects of patients' age, sex, and profession; comparison of urban versus rural settings; weather-related effects on LB incidence; risk factors for LB acquisition by humans; and risk assessment. This chapter finishes by recommending a more thorough epidemiological surveillance for LB, including morbidity notification in some additional countries where it has not yet been fully implemented. Copyright 2009 S. Karger AG, Basel.

Ionization of Atoms by Slow Heavy Particles, Including Dark Matter.

PubMed

Roberts, B M; Flambaum, V V; Gribakin, G F

2016-01-15

Atoms and molecules can become ionized during the scattering of a slow, heavy particle off a bound electron. Such an interaction involving leptophilic weakly interacting massive particles (WIMPs) is a promising possible explanation for the anomalous 9σ annual modulation in the DAMA dark matter direct detection experiment [R. Bernabei et al., Eur. Phys. J. C 73, 2648 (2013)]. We demonstrate the applicability of the Born approximation for such an interaction by showing its equivalence to the semiclassical adiabatic treatment of atomic ionization by slow-moving WIMPs. Conventional wisdom has it that the ionization probability for such a process should be exponentially small. We show, however, that due to nonanalytic, cusplike behavior of Coulomb functions close to the nucleus this suppression is removed, leading to an effective atomic structure enhancement. We also show that electron relativistic effects actually give the dominant contribution to such a process, enhancing the differential cross section by up to 1000 times.

Lattice dynamical and dielectric properties of L-amino acids

NASA Astrophysics Data System (ADS)

Tulip, P. R.; Clark, S. J.

2006-08-01

We present the results of ab initio calculations of the lattice dynamical and dielectric properties of the L-amino acids L-alanine, L-leucine, and L-isoleucine. Normal-mode frequencies and dielectric permittivity tensors are obtained using density-functional perturbation theory implemented within the plane-wave pseudopotential approximation. IR spectra are calculated and are used to analyze the effects of intermolecular interactions and zwitterionization upon the lattice dynamics. It is found that vibronic modes associated with the carboxy and amino functional groups undergo modification from their free-molecule values due to the presence of hydrogen bonds. The role of macroscopic electric fields set up by zone-center normal modes in the lattice dynamics is investigated by analysis of the Born effective charge. Calculated permittivity tensors are found to be greater than would be obtained by a naive use of the isolated molecular values, indicating the role of intermolecular interactions in increasing molecular polarizability.

Non-Markovian Investigation of an Autonomous Quantum Heat Engine

NASA Astrophysics Data System (ADS)

Goyal, Ketan

A systematic study of a quantum heat engine is presented in this thesis. In particular, we study heat conduction through a two-two level composite system, which is then connected to a photon cavity to extract work, forming an autonomous quantum heat engine. The question as to what extent quantum effects such as quantum coherence and correlations impact thermodynamic properties of such a system is addressed. The investigated heat engine has been previously studied using the popular Born-Markovian quantum master equation under weak internal coupling approximation. However, we show that the used approach is quite limited in addressing such problems as it is incapable of correctly accounting for the quantum effects. By using a non-Markovian approach involving hierarchical equations of motion, we show that quantum coherence and correlations between system and environments play a significant role in energy transfer processes of heat conduction and work.

Cognitive development in 7- to 24-month-old extremely/very-to-moderately/late preterm and full-term born infants: The mediating role of focused attention.

PubMed

Reuner, Gitta; Weinschenk, Andrea; Pauen, Sabina; Pietz, Joachim

2015-01-01

The present study analyzed the links between prematurity, attention, and global cognitive performance in infancy and early childhood. At 7 months, focused attention (FA) was examined with an object examination task in 93 preterm infants (39 of them born extremely/very preterm, 54 born moderately/late preterm, and 38 infants born full-term). Global cognition was assessed at 7 and 24 months with the Bayley-II cognitive scale. Groups did not differ with respect to global cognitive performance but FA of infants born extremely/very preterm was significantly lower than in infants born moderately/late preterm. FA correlated significantly with both prematurity and cognitive performance at 7 months of age but not with global cognition in childhood. Findings point to a subtle adverse effect of prematurity on early attention and reveal evidence for the mediating role of FA on the effect of prematurity on cognition.

Young Adult Outcomes of Children Born to Teen Mothers: Effects of Being Born during Their Teen or Later Years

ERIC Educational Resources Information Center

Lipman, Ellen L.; Georgiades, Katholiki; Boyle, Michael H.

2011-01-01

Objective: Children of teen mothers exhibit adverse outcomes through adolescence. It is unclear whether these adverse outcomes extend to adulthood and apply to all of her children, or only those born when she was a teen. We examine the associations between young adult functioning and being born to a teen mother aged less than or equal to 20 years…

Structural Growth Trajectories and Rates of Change in the First 3 Months of Infant Brain Development

PubMed Central

Holland, Dominic; Chang, Linda; Ernst, Thomas M.; Curran, Megan; Buchthal, Steven D.; Alicata, Daniel; Skranes, Jon; Johansen, Heather; Hernandez, Antonette; Yamakawa, Robyn; Kuperman, Joshua M.; Dale, Anders M.

2016-01-01

IMPORTANCE The very early postnatal period witnesses extraordinary rates of growth, but structural brain development in this period has largely not been explored longitudinally. Such assessment may be key in detecting and treating the earliest signs of neurodevelopmental disorders. OBJECTIVE To assess structural growth trajectories and rates of change in the whole brain and regions of interest in infants during the first 3 months after birth. DESIGN, SETTING, AND PARTICIPANTS Serial structural T1-weighted and/or T2-weighted magnetic resonance images were obtained for 211 time points from 87 healthy term-born or term-equivalent preterm-born infants, aged 2 to 90 days, between October 5, 2007, and June 12, 2013. MAIN OUTCOMES AND MEASURES We segmented whole-brain and multiple subcortical regions of interest using a novel application of Bayesian-based methods. We modeled growth and rate of growth trajectories nonparametrically and assessed left-right asymmetries and sexual dimorphisms. RESULTS Whole-brain volume at birth was approximately one-third of healthy elderly brain volume, and did not differ significantly between male and female infants (347 388 mm3 and 335 509 mm3, respectively, P = .12). The growth rate was approximately 1%/d, slowing to 0.4%/d by the end of the first 3 months, when the brain reached just more than half of elderly adult brain volume. Overall growth in the first 90 days was 64%. There was a significant age-by-sex effect leading to widening separation in brain sizes with age between male and female infants (with male infants growing faster than females by 200.4 mm3/d, SE = 67.2, P = .003). Longer gestation was associated with larger brain size (2215 mm3/d, SE = 284, P = 4×10−13). The expected brain size of an infant born one week earlier than average was 5% smaller than average; at 90 days it will not have caught up, being 2% smaller than average. The cerebellum grew at the highest rate, more than doubling in 90 days, and the hippocampus grew at the slowest rate, increasing by 47% in 90 days. There was left-right asymmetry in multiple regions of interest, particularly the lateral ventricles where the left was larger than the right by 462 mm3 on average (approximately 5% of lateral ventricular volume at 2 months). We calculated volume-by-age percentile plots for assessing individual development. CONCLUSIONS AND RELEVANCE Normative trajectories for early postnatal brain structural development can be determined from magnetic resonance imaging and could be used to improve the detection of deviant maturational patterns indicative of neurodevelopmental disorders. PMID:25111045

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.

Birth weight and fetal growth in infants born to female hairdressers and their sisters.

PubMed

Axmon, A; Rylander, L

2009-03-01

To investigate birth weight and fetal growth in female hairdressers, while controlling for intergenerational effects and effects related to childhood exposures. A cohort of women who had attended vocational schools for hairdressers were compared to their sisters with respect to birth weight and fetal growth (measured as small for gestational age (SGA) or large for gestational age (LGA), respectively) in their infants. In total, 6223 infants born to 3137 hairdressers and 8388 infants born to 3952 hairdressers' sisters were studied. Among the infants born to the hairdressers' sisters, the distribution of birth weights were wider than that among the infants born to the hairdressers. This was also reflected in that hairdresser cohort affiliation tended to be protective against both SGA (odds ratio 0.80; 95% confidence interval 0.49 to 1.31) and LGA (0.77; 0.54 to 1.09). For LGA, this effect was even more pronounced among women who had actually worked as hairdressers during at least one pregnancy (0.60; 0.39 to 0.92). The infants born to these women also had a significantly lower mean birth weight (3387 g vs 3419 g; p = 0.033). The results from the present study suggest that infants born to hairdressers have a decreased risk of being LGA. This is most likely not caused by a shift in birth weight distribution or abnormal glucose metabolism.

Arbuscular mycorrhizal fungal spores host bacteria that affect nutrient biodynamics and biocontrol of soil-borne plant pathogens

PubMed Central

Cruz, Andre Freire; Ishii, Takaaki

2012-01-01

Summary The aim of this research was to isolate and characterize bacteria from spores of arbuscular mycorrhizal fungi (AMF). We designated these bacteria ‘probable endobacteria’ (PE). Three bacterial strains were isolated from approximately 500 spores of Gigaspora margarita (Becker and Hall) using a hypodermic needle (diameter, 200 μm). The bacteria were identified by morphological methods and on the basis of ribosomal gene sequences as Bacillus sp. (KTCIGM01), Bacillus thuringiensis (KTCIGM02), and Paenibacillus rhizospherae (KTCIGM03). We evaluated the effect of these probable endobacteria on antagonistic activity to the soil-borne plant pathogens (SBPPs) Fusarium oxysporum f. sp. lactucae MAFF 744088, Rosellinia necatrix, Rhizoctonia solani MAFF 237426, and Pythium ultimum NBRC 100123. We also tested whether these probable endobacteria affected phosphorus solubilization, ethylene production, nitrogenase activity (NA), and stimulation of AMF hyphal growth. In addition, fresh samples of spores and hyphae were photographed using an in situ scanning electron microscope (SEM) (Quanta 250FEG; FEI Co., Japan). Bacterial aggregates (BAs), structures similar to biofilms, could be detected on the surface of hyphae and spores. We demonstrate that using extraction with an ultrathin needle, it is possible to isolate AMF-associated bacterial species that are likely derived from inside the fungal spores. PMID:23213368

Adult Tobacco Use Levels After Intensive Tobacco Control Measures: New York City, 2002–2003

PubMed Central

Frieden, Thomas R.; Mostashari, Farzad; Kerker, Bonnie D.; Miller, Nancy; Hajat, Anjum; Frankel, Martin

2005-01-01

Objectives. We sought to determine the impact of comprehensive tobacco control measures in New York City. Methods. In 2002, New York City implemented a tobacco control strategy of (1) increased cigarette excise taxes; (2) legal action that made virtually all work-places, including bars and restaurants, smoke free; (3) increased cessation services, including a large-scale free nicotine-patch program; (4) education; and (5) evaluation. The health department also began annual surveys on a broad array of health measures, including smoking. Results. From 2002 to 2003, smoking prevalence among New York City adults decreased by 11% (from 21.6% to 19.2%, approximately 140000 fewer smokers). Smoking declined among all age groups, race/ethnicities, and education levels; in both genders; among both US-born and foreign-born persons; and in all 5 boroughs. Increased taxation appeared to account for the largest proportion of the decrease; however, between 2002 and 2003 the proportion of cigarettes purchased outside New York City doubled, reducing the effective price increase by a third. Conclusions. Concerted local action can sharply reduce smoking prevalence. However, further progress will require national action, particularly to increase cigarette taxes, reduce cigarette tax evasion, expand education and cessation services, and limit tobacco marketing. PMID:15914827

Viral hepatitis in a homeless shelter in Hawai'i.

PubMed

Boyce, Daniel E C; Tice, Alan D; Ona, Fernando V; Akinaka, Kenneth T; Lusk, Heather

2009-06-01

It is estimated that as many as 21,000 people in the state of Hawai'i may be infected with HCV Most of those infected with viral hepatitis are unaware they are infected. Complications from viral hepatitis include liver cirrhosis and hepatocellular carcinoma. Hawai'i has the highest incidence of hepatocellular carcinoma in the United States. In 2003 there were over 6000 homeless and over 155,000 people at-risk of becoming homeless living in the state of Hawai'i. Risk factors for hepatitis, such as drug use, tattoos, sexual contact, and sharing of personal hygiene equipment are more prevalent in the homeless population. To determine the incidence of hepatitis B and C among a population of homeless individuals, a health fair was held at a Honolulu area homeless shelter with approximately 200 residents. The incidence of hepatitis B and C was determined by anti-HCV and HBsAg blood tests. A survey was also conducted regarding risk factors and basic demographics. Fifty-nine homeless adults volunteered for testing and took the survey. Thirty-one (52%) volunteers were born in Micronesia, twenty-four (41%) were born in the United States, two (3%) were born in Samoa, one (2%) was born in the Philippines, and one (2%) was born in the Marshall Islands. Forty adults were tested for Hepatitis C antibody, three of which tested positive. The primary risk factor among this group was jail time (100%), followed by illegal drug injection (67%), tattoos (67%), ear/body piercing (67%), snorting drugs (33%), blood transfusions (33%), and a sex partner with hepatitis (33%). Forty adults were also tested for HBsAg, One of which tested positive. This was a recent immigrant from Micronesia. Homeless people in Hawai'i are more likely to have hepatitis B or C because risk factors are common among this population. Additionally a large proportion of Hawai'i's homeless people come from the Pacific Islands, where the prevalence of hepatitis B is one of the highest in the world. In addition there are significant risks of hepatitis spread among the homeless and into the general population as many homeless do not realize they are infected. The health fair approach was an effective means for screening homeless people for hepatitis B and C. Our preliminary information suggests homeless shelters may be a good place for education, screening, and possibly interventions as well.

The influence of a long-term growth hormone treatment on lipid and glucose metabolism: a randomized trial in short Japanese children born small for gestational age.

PubMed

Horikawa, Reiko; Tanaka, Toshiaki; Nishinaga, Hiromi; Ogawa, Yoshihisa; Yokoya, Susumu

2016-01-01

Long-term growth hormone (GH) treatments in short children born small for gestational age (SGA) restore lipid metabolism, but also increase insulin resistance. The aim of this study was to evaluate the influence of long-term GH therapy on lipid and glucose metabolism as well as its dose dependency in short Japanese children born SGA. Eighty Japanese children with a short stature who were born SGA participated in this study; 65 were treated with fixed GH doses of 0.033 (low) or 0.067 (high) mg/kg/day for 260 weeks; 15 were untreated controls in the first year and were randomized to one of the two treatment groups at week 52. Serum cholesterol, glucose and insulin levels were regularly measured. An oral glucose tolerance test (OGTT) was conducted annually. The mean age at the start of GH therapy was approximately 5.3 years. Serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) in the high dose group significantly decreased over time during GH therapy. In both dose groups for TC, and in the high dose group for LDL-C, the higher the baseline values, the greater the decrease after 260 weeks. The rate of the decrease observed after 260 weeks in patients with high LDL-C levels was greater in the high dose group. Based on the results of OGTT, no patient was classified as being diabetic; however, annual increases were observed in post-OGTT insulin levels. After 260 weeks, the homeostasis model assessment as an index of insulin resistance (HOMA-IR) increased, suggesting that insulin resistance developed over time with the GH treatment, while 36.6 % of the subjects entered puberty. Long-term continuous GH treatment for children born SGA may have a potentially beneficial effect on several parameters in lipid metabolism and does not adversely affect glucose metabolism. GHLIQUID-1516, GHLIQUID-1517, Japan Pharmaceutical Information Center Clinical trial registration: JapicCTI-050132. Registered 13 September 2005. Retrospectively registered. JapicCTI-050137. Registered 13 September 2005. Retrospectively registered. ClinicalTrials.gov trial registration: NCT00184717. Registered 13 September 2005. Retrospectively registered.

Interventions for the prevention of nutritional rickets in term born children.

PubMed

Lerch, C; Meissner, T

2007-10-17

Nutritional rickets is a disease of growing children leading to bone deformities, bone pain, convulsions or delayed motor development. Today, high-incidence of nutritional rickets is mainly found in low-income countries. To assess the effects of various interventions on the prevention of nutritional rickets in term born children. Studies were obtained from computerised searches of The Cochrane Library, MEDLINE, EMBASE, LILACS and reference lists of relevant articles. We contacted authors of studies or reviews to obtain further studies. Studies were included if they were randomised controlled clinical trials, controlled clinical trials or prospective cohort studies comparing any intervention for the prevention of nutritional rickets in term born children with placebo or no intervention. Minimum duration of the intervention was three months for children under 12 months or six months for children over 12 months. Two authors independently extracted data and assessed study quality. Authors of studies were contacted to obtain missing information. Four studies enrolled approximately 1700 participants. Trials lasted between nine months to two years. Three studies were randomised controlled trials, two of which showed a cluster randomised design; one trial probably was a controlled trial with researcher controlled group assignment. In children up to three years of age in Turkey, Vitamin D compared to no intervention showed a relative risk of 0.04 (95% confidence interval (CI) 0 to 0.71). Despite a marked non-compliance, a Chinese trial in children up to three years of age comparing a combined intervention of supplementation of vitamin D, calcium and nutritional counseling showed a relative risk of 0.76 (95% CI 0.61 to 0.95) compared to no intervention. In two studies conducted in older children in China and in France no rickets occurred in both the intervention and control group. There a only few studies on the prevention of nutritional rickets in term born children. Until new data become available, it appears sound to offer preventive measures (vitamin D or calcium) to groups of high risk, like infants and toddlers; children living in Africa, Asia or the Middle East or migrated children from these regions into areas where rickets is not frequent. Due to a marked clinical heterogeneity and the scarcity of data, the main and adverse effects of preventive measures against nutritional rickets should be investigated in different countries, different age groups and in children of different ethnic origin.

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 Latino Paradox in Neighborhood Context: The Case of Asthma and Other Respiratory Conditions

PubMed Central

Cagney, Kathleen A.; Browning, Christopher R.; Wallace, Danielle M.

2007-01-01

Objectives. Evidence indicates that foreign-born Latinos have a health advantage compared with US-born persons of the same socioeconomic status. An explanation for this paradox has remained elusive. We examined the extent to which this paradox exists for the prevalence of asthma and other respiratory conditions. We then explored the role of neighborhood social context in understanding any observed advantage. We invoked theories of social organization, collective efficacy, and the urban ethnic enclave. Methods. We combined data from the Project on Human Development in Chicago Neighborhoods Community Survey with 2 other data sources and used hierarchical generalized linear modeling techniques. Results. We found a distinctly graded effect for asthma and other breathing problems among foreign-born Latinos, depending on community composition. Foreign-born Latinos embedded in a neighborhood that had a high percentage of foreign-born residents experienced a significantly lower prevalence of asthma and other breathing problems; those in communities that had a low percentage of foreign-born residents had the highest prevalence overall (even when compared with African Americans). Conclusions. Foreign-born Latinos have a respiratory health advantage only in enclave-like settings. Contexts such as these may provide the cohesiveness critical for effective prevention. PMID:17395846

Closing the Communication Gap

ERIC Educational Resources Information Center

Walmsley, Angela L. E.

2011-01-01

The three generations--Baby Boomer (born between 1946 and 1965), Generation X (born between 1967 and 1975), and Generation Y (born between 1976 and 2000)--have different styles of communication, yet teachers of all ages still have to work together effectively. Teachers can improve their relationships with their colleagues if they understand more…

Classroom Communication and Teaching Effectiveness: The Foreign-Born Instructor.

ERIC Educational Resources Information Center

Neves, Joao S.; Sanyal, Rajib N.

1991-01-01

Results of a survey of 260 students to examine how they perceive foreign-born instructors (FBIs) revealed a marked preference for native-born instructors by respondents. Because the need to hire FBIs will continue, administrators must focus attention on improving the FBIs' communication and teaching skills. (JOW)

Non-adiabatic effects in elementary reaction processes at metal surfaces

NASA Astrophysics Data System (ADS)

Alducin, M.; Díez Muiño, R.; Juaristi, J. I.

2017-12-01

Great success has been achieved in the modeling of gas-surface elementary processes by the use of the Born-Oppenheimer approximation. However, in metal surfaces low energy electronic excitations are generated even by thermal and hyperthermal molecules due to the absence of band gaps in the electronic structure. This shows the importance of performing dynamical simulations that incorporate non-adiabatic effects to analyze in which way they affect most common gas-surface reactions. Here we review recent theoretical developments in this problem and their application to the study of the effect of electronic excitations in the adsorption and relaxation of atoms and molecules in metal surfaces, in scattering processes, and also in recombinative processes between impinging atoms and adsorbates at the surface. All these studies serve us to establish what properties of the gas-surface interaction favor the excitation of low-energy electron-hole pairs. A general observation is that the nature of these excitations usually requires long lasting interactions at the surface in order to observe deviations from the adiabatic behaviour. We also provide the basis of the local density friction approximation (LDFA) that have been used in all these studies, and show how it has been employed to perform ab initio molecular dynamics with electronic friction (AIMDEF). As a final remark, we will shortly review on recent applications of the LDFA to successfully simulate desorption processes induced by intense femtosecond laser pulses.

A Model with Ellipsoidal Scatterers for Polarimetric Remote Sensing of Anisotropic Layered Media

NASA Technical Reports Server (NTRS)

Nghiem, S. V.; Kwok, R.; Kong, J. A.; Shin, R. T.

1993-01-01

This paper presents a model with ellipsoidal scatterers for applications to polarimetric remote sensing of anisotropic layered media at microwave frequencies. The physical configuration includes an isotropic layer covering an anisotropic layer above a homogeneous half space. The isotropic layer consists of randomly oriented spheroids. The anisotropic layer contains ellipsoidal scatterers with a preferential vertical alignment and random azimuthal orientations. Effective permittivities of the scattering media are calculated with the strong fluctuation theory extended to account for the nonspherical shapes and the scatterer orientation distributions. On the basis of the analytic wave theory, dyadic Green's functions for layered media are used to derive polarimetric backscattering coefficients under the distorted Born approximation. The ellipsoidal shape of the scatterers gives rise to nonzero cross-polarized returns from the untilted anisotropic medium in the first-order approximation. Effects of rough interfaces are estimated by an incoherent addition method. Theoretical results and experimental data are matched at 9 GHz for thick first-year sea ice with a bare surface and with a snow cover at Point Barrow, Alaska. The model is then used to study the sensitivity of polarimetric backscattering coefficients with respect to correlation lengths representing the geometry of brine inclusions. Polarimetric signatures of bare and snow-covered sea ice are also simulated based on the model to investigate effects of different scattering mechanisms.

A Model Framework to Estimate Impact and Cost of Genetics-Based Sterile Insect Methods for Dengue Vector Control

PubMed Central

Alphey, Nina; Alphey, Luke; Bonsall, Michael B.

2011-01-01

Vector-borne diseases impose enormous health and economic burdens and additional methods to control vector populations are clearly needed. The Sterile Insect Technique (SIT) has been successful against agricultural pests, but is not in large-scale use for suppressing or eliminating mosquito populations. Genetic RIDL technology (Release of Insects carrying a Dominant Lethal) is a proposed modification that involves releasing insects that are homozygous for a repressible dominant lethal genetic construct rather than being sterilized by irradiation, and could potentially overcome some technical difficulties with the conventional SIT technology. Using the arboviral disease dengue as an example, we combine vector population dynamics and epidemiological models to explore the effect of a program of RIDL releases on disease transmission. We use these to derive a preliminary estimate of the potential cost-effectiveness of vector control by applying estimates of the costs of SIT. We predict that this genetic control strategy could eliminate dengue rapidly from a human community, and at lower expense (approximately US$ 2∼30 per case averted) than the direct and indirect costs of disease (mean US$ 86–190 per case of dengue). The theoretical framework has wider potential use; by appropriately adapting or replacing each component of the framework (entomological, epidemiological, vector control bio-economics and health economics), it could be applied to other vector-borne diseases or vector control strategies and extended to include other health interventions. PMID:21998654

Polarized optical scattering by inhomogeneities and surface roughness in an anisotropic thin film.

PubMed

Germer, Thomas A; Sharma, Katelynn A; Brown, Thomas G; Oliver, James B

2017-11-01

We extend the theory of Kassam et al. [J. Opt. Soc. Am. A12, 2009 (1995)JOAOD60740-323210.1364/JOSAA.12.002009] for scattering by oblique columnar structure thin films to include the induced form birefringence and the propagation of radiation in those films. We generalize the 4×4 matrix theory of Berreman [J. Opt. Soc. Am.62, 502 (1972)JOSAAH0030-394110.1364/JOSA.62.000502] to include arbitrary sources in the layer, which are necessary to determine the Green function for the inhomogeneous wave equation. We further extend first-order vector perturbation theory for scattering by roughness in the smooth surface limit, when the layer is anisotropic. Scattering by an inhomogeneous medium is approximated by a distorted Born approximation, where effective medium theory is used to determine the effective properties of the medium, and strong fluctuation theory is used to determine the inhomogeneous sources. In this manner, we develop a model for scattering by inhomogeneous films, with anisotropic correlation functions. The results are compared with Mueller matrix bidirectional scattering distribution function measurements for a glancing-angle deposition (GLAD) film. While the results are applied to the GLAD film example, the development of the theory is general enough that it can guide simulations for scattering in other anisotropic thin films.

Non-Markovian quantum Brownian motion in one dimension in electric fields

NASA Astrophysics Data System (ADS)

Shen, H. Z.; Su, S. L.; Zhou, Y. H.; Yi, X. X.

2018-04-01

Quantum Brownian motion is the random motion of quantum particles suspended in a field (or an effective field) resulting from their collision with fast-moving modes in the field. It provides us with a fundamental model to understand various physical features concerning open systems in chemistry, condensed-matter physics, biophysics, and optomechanics. In this paper, without either the Born-Markovian or rotating-wave approximation, we derive a master equation for a charged-Brownian particle in one dimension coupled with a thermal reservoir in electric fields. The effect of the reservoir and the electric fields is manifested as time-dependent coefficients and coherent terms, respectively, in the master equation. The two-photon correlation between the Brownian particle and the reservoir can induce nontrivial squeezing dynamics to the particle. We derive a current equation including the source from the driving fields, transient current from the system flowing into the environment, and the two-photon current caused by the non-rotating-wave term. The presented results then are compared with that given by the rotating-wave approximation in the weak-coupling limit, and these results are extended to a more general quantum network involving an arbitrary number of coupled-Brownian particles. The presented formalism might open a way to better understand exactly the non-Markovian quantum network.

Increasing Prevalence of Myopia in Europe and the Impact of Education

PubMed Central

Williams, Katie M.; Bertelsen, Geir; Cumberland, Phillippa; Wolfram, Christian; Verhoeven, Virginie J.M.; Anastasopoulos, Eleftherios; Buitendijk, Gabriëlle H.S.; Cougnard-Grégoire, Audrey; Creuzot-Garcher, Catherine; Erke, Maja Gran; Hogg, Ruth; Höhn, René; Hysi, Pirro; Khawaja, Anthony P.; Korobelnik, Jean-François; Ried, Janina; Vingerling, Johannes R.; Bron, Alain; Dartigues, Jean-François; Fletcher, Astrid; Hofman, Albert; Kuijpers, Robert W.A.M.; Luben, Robert N.; Oxele, Konrad; Topouzis, Fotis; von Hanno, Therese; Mirshahi, Alireza; Foster, Paul J.; van Duijn, Cornelia M.; Pfeiffer, Norbert; Delcourt, Cécile; Klaver, Caroline C.W.; Rahi, Jugnoo; Hammond, Christopher J.

2015-01-01

Purpose To investigate whether myopia is becoming more common across Europe and explore whether increasing education levels, an important environmental risk factor for myopia, might explain any temporal trend. Design Meta-analysis of population-based, cross-sectional studies from the European Eye Epidemiology (E3) Consortium. Participants The E3 Consortium is a collaborative network of epidemiological studies of common eye diseases in adults across Europe. Refractive data were available for 61 946 participants from 15 population-based studies performed between 1990 and 2013; participants had a range of median ages from 44 to 78 years. Methods Noncycloplegic refraction, year of birth, and highest educational level achieved were obtained for all participants. Myopia was defined as a mean spherical equivalent ≤−0.75 diopters. A random-effects meta-analysis of age-specific myopia prevalence was performed, with sequential analyses stratified by year of birth and highest level of educational attainment. Main Outcome Measures Variation in age-specific myopia prevalence for differing years of birth and educational level. Results There was a significant cohort effect for increasing myopia prevalence across more recent birth decades; age-standardized myopia prevalence increased from 17.8% (95% confidence interval [CI], 17.6–18.1) to 23.5% (95% CI, 23.2–23.7) in those born between 1910 and 1939 compared with 1940 and 1979 (P = 0.03). Education was significantly associated with myopia; for those completing primary, secondary, and higher education, the age-standardized prevalences were 25.4% (CI, 25.0–25.8), 29.1% (CI, 28.8–29.5), and 36.6% (CI, 36.1–37.2), respectively. Although more recent birth cohorts were more educated, this did not fully explain the cohort effect. Compared with the reference risk of participants born in the 1920s with only primary education, higher education or being born in the 1960s doubled the myopia prevalence ratio–2.43 (CI, 1.26–4.17) and 2.62 (CI, 1.31–5.00), respectively—whereas individuals born in the 1960s and completing higher education had approximately 4 times the reference risk: a prevalence ratio of 3.76 (CI, 2.21–6.57). Conclusions Myopia is becoming more common in Europe; although education levels have increased and are associated with myopia, higher education seems to be an additive rather than explanatory factor. Increasing levels of myopia carry significant clinical and economic implications, with more people at risk of the sight-threatening complications associated with high myopia. PMID:25983215

Increasing Prevalence of Myopia in Europe and the Impact of Education.

PubMed

Williams, Katie M; Bertelsen, Geir; Cumberland, Phillippa; Wolfram, Christian; Verhoeven, Virginie J M; Anastasopoulos, Eleftherios; Buitendijk, Gabriëlle H S; Cougnard-Grégoire, Audrey; Creuzot-Garcher, Catherine; Erke, Maja Gran; Hogg, Ruth; Höhn, René; Hysi, Pirro; Khawaja, Anthony P; Korobelnik, Jean-François; Ried, Janina; Vingerling, Johannes R; Bron, Alain; Dartigues, Jean-François; Fletcher, Astrid; Hofman, Albert; Kuijpers, Robert W A M; Luben, Robert N; Oxele, Konrad; Topouzis, Fotis; von Hanno, Therese; Mirshahi, Alireza; Foster, Paul J; van Duijn, Cornelia M; Pfeiffer, Norbert; Delcourt, Cécile; Klaver, Caroline C W; Rahi, Jugnoo; Hammond, Christopher J

2015-07-01

To investigate whether myopia is becoming more common across Europe and explore whether increasing education levels, an important environmental risk factor for myopia, might explain any temporal trend. Meta-analysis of population-based, cross-sectional studies from the European Eye Epidemiology (E(3)) Consortium. The E(3) Consortium is a collaborative network of epidemiological studies of common eye diseases in adults across Europe. Refractive data were available for 61 946 participants from 15 population-based studies performed between 1990 and 2013; participants had a range of median ages from 44 to 78 years. Noncycloplegic refraction, year of birth, and highest educational level achieved were obtained for all participants. Myopia was defined as a mean spherical equivalent ≤-0.75 diopters. A random-effects meta-analysis of age-specific myopia prevalence was performed, with sequential analyses stratified by year of birth and highest level of educational attainment. Variation in age-specific myopia prevalence for differing years of birth and educational level. There was a significant cohort effect for increasing myopia prevalence across more recent birth decades; age-standardized myopia prevalence increased from 17.8% (95% confidence interval [CI], 17.6-18.1) to 23.5% (95% CI, 23.2-23.7) in those born between 1910 and 1939 compared with 1940 and 1979 (P = 0.03). Education was significantly associated with myopia; for those completing primary, secondary, and higher education, the age-standardized prevalences were 25.4% (CI, 25.0-25.8), 29.1% (CI, 28.8-29.5), and 36.6% (CI, 36.1-37.2), respectively. Although more recent birth cohorts were more educated, this did not fully explain the cohort effect. Compared with the reference risk of participants born in the 1920s with only primary education, higher education or being born in the 1960s doubled the myopia prevalence ratio-2.43 (CI, 1.26-4.17) and 2.62 (CI, 1.31-5.00), respectively-whereas individuals born in the 1960s and completing higher education had approximately 4 times the reference risk: a prevalence ratio of 3.76 (CI, 2.21-6.57). Myopia is becoming more common in Europe; although education levels have increased and are associated with myopia, higher education seems to be an additive rather than explanatory factor. Increasing levels of myopia carry significant clinical and economic implications, with more people at risk of the sight-threatening complications associated with high myopia. Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

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.

Dissemination of periodic mammography and patterns of use, by birth cohort, in Catalonia (Spain)

PubMed Central

Rue, Montserrat; Carles, Misericordia; Vilaprinyo, Ester; Martinez-Alonso, Montserrat; Espinas, Josep-Alfons; Pla, Roger; Brugulat, Pilar

2008-01-01

Background In Catalonia (Spain) breast cancer mortality has declined since the beginning of the 1990s. The dissemination of early detection by mammography and the introduction of adjuvant treatments are among the possible causes of this decrease, and both were almost coincident in time. Thus, understanding how these procedures were incorporated into use in the general population and in women diagnosed with breast cancer is very important for assessing their contribution to the reduction in breast cancer mortality. In this work we have modeled the dissemination of periodic mammography and described repeat mammography behavior in Catalonia from 1975 to 2006. Methods Cross-sectional data from three Catalan Health Surveys for the calendar years 1994, 2002 and 2006 was used. The dissemination of mammography by birth cohort was modeled using a mixed effects model and repeat mammography behavior was described by age and survey year. Results For women born from 1938 to 1952, mammography clearly had a period effect, meaning that they started to have periodic mammograms at the same calendar years but at different ages. The age at which approximately 50% of the women were receiving periodic mammograms went from 57.8 years of age for women born in 1938–1942 to 37.3 years of age for women born in 1963–1967. Women in all age groups experienced an increase in periodic mammography use over time, although women in the 50–69 age group have experienced the highest increase. Currently, the target population of the Catalan Breast Cancer Screening Program, 50–69 years of age, is the group that self-reports the highest utilization of periodic mammograms, followed by the 40–49 age group. A higher proportion of women of all age groups have annual mammograms rather than biennial or irregular ones. Conclusion Mammography in Catalonia became more widely implemented during the 1990s. We estimated when cohorts initiated periodic mammograms and how frequently women are receiving them. These two pieces of information will be entered into a cost-effectiveness model of early detection in Catalonia. PMID:19014679

Impact of maternal obesity on inhaled corticosteroid use in childhood: a registry based analysis of first born children and a sibling pair analysis.

PubMed

Lowe, Adrian J; Ekeus, Cecilia; Bråbäck, Lennart; Rajaleid, Kristiina; Forsberg, Bertil; Hjern, Anders

2013-01-01

It has been proposed that maternal obesity during pregnancy may increase the risk that the child develops allergic disease and asthma, although the mechanisms underpinning this relationship are currently unclear. We sought to assess if this association may be due to confounding by genetic or environmental risk factors that are common to maternal obesity and childhood asthma, using a sibling pair analysis. The study population comprised a Swedish national cohort of term children born between 1992 and 2008 to native Swedish parents. Maternal body mass index (BMI) was measured at 8-10 weeks gestation. Unconditional logistic regression models were used to determine if maternal obesity was associated with increased risk of inhaled corticosteroid (ICS) in 431,718 first-born children, while adjusting for potential confounders. An age-matched discordant sib-pair analysis was performed, taking into account shared genetic and environmental risk factors. Maternal over-weight and obesity were associated with increased risk that the child would require ICS (for BMI≥35 kg/m(2), aOR = 1.30, 95%CI = 1.10-1.52 compared with normal weight mothers) in children aged 6-12 years. Similar effects were seen in younger children, but in children aged 13-16 years, maternal obesity (BMI≥30) was related to increased risk of ICS use in girls (aOR = 1.28, 95%CI = 1.07-1.53) but not boys (OR = 1.05, 95%CI = 0.87-1.26). The sib-pair analysis, which included 2,034 sib-pairs older than six years who were discordant for both ICS use and maternal BMI category, failed to find any evidence that increasing maternal weight was related to increased risk of ICS use. Maternal obesity is associated with increased risk of childhood ICS use up to approximately 12 years of age, but only in girls after this age. These effects could not be confirmed in a sib pair analysis, suggesting either limited statistical power, or the effects of maternal BMI may be due to shared genetic or environmental risk factors.

Effect of zinc supplementation on neuronal precursor proliferation in the rat hippocampus after traumatic brain injury.

PubMed

Cope, Elise C; Morris, Deborah R; Gower-Winter, Shannon D; Brownstein, Naomi C; Levenson, Cathy W

2016-05-01

There is great deal of debate about the possible role of adult-born hippocampal cells in the prevention of depression and related mood disorders. We first showed that zinc supplementation prevents the development of the depression-like behavior anhedonia associated with an animal model of traumatic brain injury (TBI). This work then examined the effect of zinc supplementation on the proliferation of new cells in the hippocampus that have the potential to participate in neurogenesis. Rats were fed a zinc adequate (ZA, 30ppm) or zinc supplemented (ZS, 180ppm) diet for 4wk followed by TBI using controlled cortical impact. Stereological counts of EdU-positive cells showed that TBI doubled the density of proliferating cells 24h post-injury (p<0.05), and supplemental zinc significantly increased this by an additional 2-fold (p<0.0001). While the survival of these proliferating cells decreased at the same rate in ZA and in ZS rats after injury, the total density of newly born cells was approximately 60% higher in supplemented rats 1wk after TBI. Furthermore, chronic zinc supplementation resulted in significant increases in the density of new doublecortin-positive neurons one week post-TBI that were maintained for 4wk after injury (p<0.01). While the effect of zinc supplementation on neuronal precursor cells in the hippocampus was robust, use of targeted irradiation to eliminate these cells after zinc supplementation and TBI revealed that these cells are not the sole mechanism through which zinc acts to prevent depression associated with brain injury, and suggest that other zinc dependent mechanisms are needed for the anti-depressant effect of zinc in this model of TBI. Copyright © 2016 Elsevier Inc. All rights reserved.

Experimental and theoretical triple differential cross sections for electron-impact ionization of Ar (3p) for equal energy final state electrons

NASA Astrophysics Data System (ADS)

Amami, Sadek; Ozer, Zehra N.; Dogan, Mevlut; Yavuz, Murat; Varol, Onur; Madison, Don

2016-09-01

There have been several studies of electron-impact ionization of inert gases for asymmetric final state energy sharing and normally one electron has an energy significantly higher than the other. However, there have been relatively few studies examining equal energy final state electrons. Here we report experimental and theoretical triple differential cross sections for electron impact ionization of Ar (3p) for equal energy sharing of the outgoing electrons. Previous experimental results combined with some new measurements are compared with distorted wave born approximation (DWBA) results, DWBA results using the Ward-Macek (WM) approximation for the post collision interaction (PCI), and three-body distorted wave (3DW) which includes PCI without approximation. The results show that it is crucially important to include PCI in the calculation particularly for lower energies and that the WM approximation is valid only for high energies. The 3DW, on the other hand, is in reasonably good agreement with data down to fairly low energies.

Pseudostate methods and differential cross sections for antiproton ionization of atomic hydrogen and helium

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

McGovern, M.; Walters, H. R. J.; Assafrao, D.

2010-03-15

A relaxed form of a recent impact parameter coupled pseudostate approximation of McGovern et al. [Phys. Rev. A 79, 042707 (2009)] for calculating differential ionization cross sections is proposed. This greatly eases the computational burden in cases where a range of ejected electron energies has to be considered. The relaxed approximation is tested against exact first Born calculations for antiproton impact on H and nonperturbatively for the highly nonperturbative system of Au{sup 53+} incident upon He. The approximation performs well in these tests. It is shown how, with a little further approximation, the relaxed theory leads to a widely usedmore » prescription for the total ionization cross section. Results for differential ionization of H and He by antiprotons are presented. These reveal the growing dominance of the interaction between the antiproton and the target nucleus at low impact energies and show the changing importance of the role of the postcollisional interaction between the antiproton and the ejected electron.« less

Early comprehensive care of preterm infants-effects on quality of life, childhood development, and healthcare utilization: study protocol for a cohort study linking administrative healthcare data with patient reported primary data.

PubMed

Schmitt, Jochen; Arnold, Katrin; Druschke, Diana; Swart, Enno; Grählert, Xina; Maywald, Ulf; Fuchs, Andreas; Werblow, Andreas; Schemken, Maryan; Reichert, Jörg; Rüdiger, Mario

2016-07-22

About 9 % of all children in Germany are born preterm. Despite significant improvements of medical care, preterm infants are at a greater risk to develop short and long term health complications. Negative consequences of preterm birth include neurodevelopmental disabilities, behavioral problems or learning disorders. Most data on effects of prematurity are derived from single or multi-center studies and not population-based. Since some of the long term problems of preterm delivery are associated with a disturbed parent-child interaction originating in the neonatal period, several intervention programs became available aiming to strengthen the early parent-child relationship. However, there is insufficient knowledge regarding the psychosocial and socioeconomic impact of these interventions. Prior to introducing them into routine care, those effects have to be rigorously evaluated. The population-based cohort study EcoCare-PIn (Early comprehensive Care of Preterm Infants-effects on quality of life, childhood development, and healthcare utilization) will investigate the following primary research questions: 1) What are the short- and long-term consequences of preterm birth with regard to parental stress, parent-child relationship, childhood development, quality of life and healthcare utilization including costs? 2) Does early family-centered psychosocial care prevent the hypothesized negative consequences of preterm birth on the above mentioned outcomes? EcoCare-PIn examines the research questions by means of a linkage of a) pseudonymized administrative individual-level claims data from the German statutory health insurance AOK PLUS on approximately 140,000 children born between 2007 and 2013 in Saxony, and b) primary data collected from the parents/caregivers of all very low birth weight (<1,500 g; n = 1,000) and low birth weight infants (1,500 to 2,500 g; n = 5,500) and a matched sample of infants above 2,500 g birth weight (n = 10,000). In Saxony, approximately 50 % of all individuals are insured at the AOK PLUS. The linkage of patient-level administrative and primary data is a novel approach in neonatal research and probably the only way to overcome shortcomings of studies solely relying on one data source. The study results are based on an observation period of up to 8 years and will directly inform perinatal healthcare provision in Saxony and Germany as a whole.

Kerr effect from diffractive skew scattering in chiral px +/- ipy superconductors

NASA Astrophysics Data System (ADS)

König, Elio; Levchenko, Alex

We calculate the temperature dependent anomalous ac Hall conductance σH (Ω , T) for a two-dimensional chiral p-wave superconductor. This quantity determines the polar Kerr effect, as it was observed in Sr2RuO4. We concentrate on a single band model with arbitrary isotropic dispersion relation subjected to rare, weak impurities treated in the Born approximation. As we explicitly show by detailed computation, previously omitted contributions to extrinsic part of an anomalous Hall response, physically originating from diffractive skew scattering on quantum impurity complexes, appear to the leading order in impurity concentration. By direct comparison with published results from the literature we demonstrate the relevance of our findings for the interpretation of the Kerr effect measurements in superconductors. This work was financially supported in part by NSF Grants No. DMR-1606517 and ECCS-1560732 and at U of Wisconsin by the Office of the Vice Chancellor for Research and Graduate Education with funding from the Wisconsin Alumni Research Foundation.

On the Feasibility of Studying Shortwave Aerosol Radiative Forcing of Climate Using Dual-Wavelength Aerosol Backscatter Lidar

NASA Technical Reports Server (NTRS)

Redemann, Jens; Russell, Philip B.; Winker, David M.; McCormick, M. Patrick; Hipskind, R. Stephen (Technical Monitor)

2000-01-01

The current low confidence in the estimates of aerosol-induced perturbations of Earth's radiation balance is caused by the highly non-uniform compositional, spatial and temporal distributions of tropospheric aerosols on a global scale owing to their heterogeneous sources and short lifetimes. Nevertheless, recent studies have shown that the inclusion of aerosol effects in climate model calculations can improve agreement with observed spatial and temporal temperature distributions. In light of the short lifetimes of aerosols, determination of their global distribution with space-borne sensors seems to be a necessary approach. Until recently, satellite measurements of tropospheric aerosols have been approximate and did not provide the full set of information required to determine their radiative effects. With the advent of active aerosol remote sensing from space (e.g., PICASSO-CENA), the applicability fo lidar-derived aerosol 180 deg -backscatter data to radiative flux calculations and hence studies of aerosol effects on climate needs to be investigated.

Co-occurrence of chronic disease lifestyle risk factors in middle-aged and older immigrants: A cross-sectional analysis of 264,102 Australians.

PubMed

Sarich, Peter Eugene Andrew; Ding, Ding; Sitas, Freddy; Weber, Marianne Frances

2015-12-01

The way in which lifestyle risk factors for chronic disease co-occur among people with different cultural backgrounds is largely unknown. This study investigated chronic disease risk among immigrants aged ≥45 years in Australia by combining common lifestyle risk factors into a weighted chronic disease risk index (CDRI). Among 64,194 immigrants and 199,908 Australian-born participants in the 45 and Up Study (2006-2009), Poisson regression was used to derive relative risks (RR) and 95% confidence intervals (CI) for five risk factors (smoking, alcohol use, overweight/obesity, physical activity, diet) by place of birth adjusting for socio-demographic characteristics. Multiple linear regression was used to determine adjusted mean differences (AMDs) in CDRI score by place of birth and years lived in Australia. Immigrants had higher RRs of smoking than Australian-born participants, lower RRs of excessive alcohol consumption and overweight/obesity, and no difference in RR for physical inactivity and insufficient fruit/vegetable intake. Participants born in the Middle East/North Africa (AMD 3.5, 95% CI 2.7, 4.3), Eastern/Central Europe (1.3, 0.8, 1.9), and Western Europe (0.5, 0.1, 0.8) had higher mean CDRI scores than Australian-born participants, while participants born in East Asia (-7.2, -7.8, -6.6), Southeast Asia (-6.6, -7.2, -6.1), Central/South Asia (-3.1, -4.0, -2.1), Sub-Saharan Africa (-1.9, -2.6, -1.2) and the United Kingdom/Ireland (-0.2, -0.5, 0.0) had lower scores. CDRI score among immigrants generally approximated that of Australian-born participants with greater years lived in Australia. This study reveals differences in potential risk of chronic disease among different immigrant groups in Australia. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Fetal programming by co-twin rivalry in sheep.

PubMed

Casellas, J; Caja, G

2014-01-01

Fetal rivalry for space and nutrients compromises intrauterine environment and fetal growth, this leading to further consequences during adult life (i.e., fetal programming). Focusing on sheep, relevant fetal programming effects have been revealed on body composition and growth although little is known about their potential impact on the reproductive performance of adult ewes. This research focused on the analysis of fetal programming-related effects on 41,475 litter size (LS) records from 7,177 purebred Ripollesa ewes. Fetal programming sources of variation accounted for the linear and quadratic effect of absolute birth BW (ABBW), relative birth BW (RBBW) of twin-born ewes (i.e., both magnitude and direction of the birth BW difference between the ewe and its co-twin), and sex of twin ewe's littermate (SLM). More specifically, data were analyzed under a threshold mixed model and the statistical relevance of models accounting for different combinations of ABBW, RBBW, and SLM effects was compared by Bayes factors (BF; i.e., the ratio between the posterior probability of 2 competing models). The model accounting for RBBW and discarding both ABBW and SLM effects was clearly preferred; its posterior probability was 35.2 to 362.3 times higher than from remaining models and provided very strong (31.6 < BF < 100) and decisive evidences (BF > 100) supporting the relevance of RBBW and the negligibility of both ABBW and SLM. Single-born ewes were included as reference group and they reached a predicted LS of 1.189 lambs per lambing. Twin-born ewes being >600 g lighter than their co-twins suffered from an impaired reproductive ability with 1.162 lambs per lambing (95% credible interval [95CI], 1.147 to 1.179), and this estimate increased until ewes were 151 to 300 g lighter than their co-twins (1.226 lambs per lambing; 95CI, 1.208 to 1.244). Remaining categories (i.e., ewes being heavier or equal than their co-twins) did not provide significant differences and showed an enhanced reproductive ability of approximately 1.23 lambs per lambing. These significant differences in LS highlighted the influence of fetal programming in sheep under rangeland conditions, which implies decisive economic consequences worldwide. Moreover, these results could contribute additional information on twin biology, which could be useful in other mammalian species such as humans.

Nonlinear effects in the laser-assisted scattering of a positron by a muon

NASA Astrophysics Data System (ADS)

Du, Wen-Yuan; Wang, Bing-Hong; Li, Shu-Min

2018-02-01

The scattering of a positron by a muon in the presence of a linearly polarized laser field is investigated in the first Born approximation. The theoretical results reveal: (1) At large scattering angle, an amount of multiphoton processes take place in the course of scattering. The photon emission processes predominate the photon absorption ones. (2) Some nonlinear phenomena about oscillations, dark angular windows, and asymmetry can be observed in angular distributions. We analyze the cause giving rise to dark windows and geometric asymmetry initially noted in the potential scattering. (3) We also analyze the total differential cross-section, the result shows that the larger the incident energy is, the smaller the total differential cross-section is. The reasons of these new results are analyzed.

Elastic, inelastic, and 1 n transfer cross sections for the B 10 + Sn 120 reaction

DOE PAGES

Gasques, L. R.; Freitas, A. S.; Chamon, L. C.; ...

2018-03-30

The 10B+ 120Sn reaction has been investigated at E Lab=37.5 MeV. The cross sections for different channels, such as the elastic scattering, the excitation of the 2 + and 3 -120Sn states, the excitation of the 1 + state of 10B, and the 1n pick-up transfer, have been measured. One-step distorted-wave Born approximation and coupled-reaction-channels calculations have been performed in the context of the double-folding São Paulo potential. Here, the effect of coupling the inelastic and transfer states on the angular distributions is discussed in the paper. In general, the theoretical calculations within the coupled-reaction-channels formalism yield a satisfactory agreementmore » with the corresponding experimental angular distributions.« less

Analisis fotometrico del cumulo abierto NGC 6611

NASA Astrophysics Data System (ADS)

Suarez Nunez, Johanna

2007-08-01

Matlab programs were designed to apply differential aperture photometry. Two images were taken with a charge-couple device ( CCD ) in the visible V and blue filters, to calculate physical parameters (the flux( f ), the apparent magnitude ( m V ) and its reddening corrected value ( V 0 ), color index ( B- V ) and ( B-V ) 0 , the log of effective temperature (log T eff ), the absolute magnitude ( M V ), the bolometric magnitude ( M B ) & log(L [low *] /[Special characters omitted.] )) of each studied star pertaining to the open cluster NGC 6611. Upon obtaining the parameters, the color-magnitude diagram was graphed and by fitting to the main sequence, the distance modulus and thus the distance to the cluster was found. The stars were assumed to be at the same distance and born at approximately the same moment.

Effect of compound nuclear reaction mechanism in 12C(6Li,d) reaction at sub-Coulomb energy

NASA Astrophysics Data System (ADS)

Mondal, Ashok; Adhikari, S.; Basu, C.

2017-09-01

The angular distribution of the 12C(6Li,d) reaction populating the 6.92 and 7.12 MeV states of 16O at sub-Coulomb energy (Ecm=3 MeV) are analysed in the framework of the Distorted Wave Born Approximation (DWBA). Recent results on excitation function measurements and backward angle angular distributions derive ANC for both the states on the basis of an alpha transfer mechanism. In the present work, we show that considering both forward and backward angle data in the analysis, the 7.12 MeV state at sub-Coulomb energy is populated from Compound nuclear process rather than transfer process. The 6.92 MeV state is however produced from direct reaction mechanism.

Elastic, inelastic, and 1 n transfer cross sections for the B 10 + Sn 120 reaction

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

Gasques, L. R.; Freitas, A. S.; Chamon, L. C.

The 10B+ 120Sn reaction has been investigated at E Lab=37.5 MeV. The cross sections for different channels, such as the elastic scattering, the excitation of the 2 + and 3 -120Sn states, the excitation of the 1 + state of 10B, and the 1n pick-up transfer, have been measured. One-step distorted-wave Born approximation and coupled-reaction-channels calculations have been performed in the context of the double-folding São Paulo potential. Here, the effect of coupling the inelastic and transfer states on the angular distributions is discussed in the paper. In general, the theoretical calculations within the coupled-reaction-channels formalism yield a satisfactory agreementmore » with the corresponding experimental angular distributions.« less

The Born approximation, multiple scattering, and the butterfly algorithm

NASA Astrophysics Data System (ADS)

Martinez, Alejandro F.

Radar works by focusing a beam of light and seeing how long it takes to reflect. To see a large region the beam is pointed in different directions. The focus of the beam depends on the size of the antenna (called an aperture). Synthetic aperture radar (SAR) works by moving the antenna through some region of space. A fundamental assumption in SAR is that waves only bounce once. Several imaging algorithms have been designed using that assumption. The scattering process can be described by iterations of a badly behaving integral. Recently a method for efficiently evaluating these types of integrals has been developed. We will give a detailed implementation of this algorithm and apply it to study the multiple scattering effects in SAR using target estimates from single scattering algorithms.

Differential cross sections for the electron impact ionization of Ar (3 p) atoms for equal energy final state electrons

NASA Astrophysics Data System (ADS)

Purohit, Ghanshyam; Singh, Prithvi

2017-06-01

The electron-impact ionization of inert gases for asymmetric final state energy sharing conditions has been studied in detail. However, there have been relatively few studies examining equal energy final state electrons. We report in this communication the results of triple differential cross sections (TDCSs) for electron impact ionization of Ar (3 p) for equal energy sharing of the outgoing electrons. We calculate TDCS in the modified distorted wave Born approximation (DWBA) formalism including post collision interaction (PCI) and polarization potential. We compare the results of our calculation with available measurements [Phys. Rev. A 87, 022712 (2013)]. We study the effect of PCI, target polarization on the trends of TDCS for the single ionization of Ar (3 p) targets.

Dynamic conductivity and plasmon profile of aluminum in the ultra-fast-matter regime

NASA Astrophysics Data System (ADS)

Dharma-wardana, M. W. C.

2016-06-01

We use an explicitly isochoric two-temperature theory to analyze recent x-ray laser scattering data for aluminum in the ultra-fast-matter (UFM) regime up to 6 eV. The observed surprisingly low conductivities are explained by including strong electron-ion scattering effects using the phase shifts calculated via the neutral-pseudo-atom model. The difference between the static conductivity for UFM-Al and equilibrium aluminum in the warm-dense matter state is clearly brought out by comparisons with available density-fucntional+molecular-dynamics simulations. Thus the applicability of the Mermin model to UFM is questioned. The static and dynamic conductivity, collision frequency, and the plasmon line shape, evaluated within the simplest Born approximation for UFM aluminum, are in good agreement with experiment.

Geometric integration in Born-Oppenheimer molecular dynamics.

PubMed

Odell, Anders; Delin, Anna; Johansson, Börje; Cawkwell, Marc J; Niklasson, Anders M N

2011-12-14

Geometric integration schemes for extended Lagrangian self-consistent Born-Oppenheimer molecular dynamics, including a weak dissipation to remove numerical noise, are developed and analyzed. The extended Lagrangian framework enables the geometric integration of both the nuclear and electronic degrees of freedom. This provides highly efficient simulations that are stable and energy conserving even under incomplete and approximate self-consistent field (SCF) convergence. We investigate three different geometric integration schemes: (1) regular time reversible Verlet, (2) second order optimal symplectic, and (3) third order optimal symplectic. We look at energy conservation, accuracy, and stability as a function of dissipation, integration time step, and SCF convergence. We find that the inclusion of dissipation in the symplectic integration methods gives an efficient damping of numerical noise or perturbations that otherwise may accumulate from finite arithmetics in a perfect reversible dynamics. © 2011 American Institute of Physics

First Principle Predictions of Isotopic Shifts in H2O

NASA Technical Reports Server (NTRS)

Schwenke, David W.; Kwak, Dochan (Technical Monitor)

2002-01-01

We compute isotope independent first and second order corrections to the Born-Oppenheimer approximation for water and use them to predict isotopic shifts. For the diagonal correction, we use icMRCI wavefunctions and derivatives with respect to mass dependent, internal coordinates to generate the mass independent correction functions. For the non-adiabatic correction, we use scaled SCF/CIS wave functions and a generalization of the Handy method to obtain mass independent correction functions. We find that including the non-adiabatic correction gives significantly improved results compared to just including the diagonal correction when the Born-Oppenheimer potential energy surface is optimized for H2O-16. The agreement with experimental results for deuterium and tritium containing isotopes is nearly as good as our best empirical correction, however, the present correction is expected to be more reliable for higher, uncharacterized levels.

Lactose intolerance: diagnosis, genetic, and clinical factors

PubMed Central

Mattar, Rejane; de Campos Mazo, Daniel Ferraz; Carrilho, Flair José

2012-01-01

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. This review discusses the lactase-persistence alleles that have arisen in different populations around the world, diagnosis of lactose intolerance, and its symptomatology and management. PMID:22826639

Multiple scaled disorder in the photonic structure of Morpho rhetenor butterfly

NASA Astrophysics Data System (ADS)

Boulenguez, J.; Berthier, S.; Leroy, F.

2012-03-01

The iridescence of Morpho rhetenor butterfly is known to result from a photonic structure on wing scales, where multilayer interference and grating diffraction occur simultaneously. We characterize the disorder at the photonic structure length scale and at the butterfly scale. We measure the scattering pattern of the wing. Through RCWA and 1st Born approximation models, we link the different disorders to different features in the scattering patterns.

Excitation energy spectrum in helium II

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

Lu, P.; Chan, C.K.

1979-11-01

We obtain the roton part of the excitation energy spectrum in He II qualitatively. We point out that the distinct difference between this calculation and that of Parry and Ter Haar is that we do not use the Born approximation in the evaluation of t-matrix elements. We found that in addition to the contribution due to the hard-core part, the attractive potential helps to form the roton dip.

Model Development for Graphene Spintronics

DTIC Science & Technology

2015-09-21

structure near the dirac point. Scattering was evaluated in born approximation. Screening and transport were treated semi-classically...requested and granted by the cognizant office, and the program ran through 25 May 2015. Graphene is a promising material for electronic and spintronic...of an insulating material such as Al2O3, to enable efficient spin injection. The graphene layer is beneath the tunnel barrier, followed by SiO2 (on

The Information Lives of Immigrant and Refugee Youth Acting as Information and Communication Technology (ICT) Wayfarers

ERIC Educational Resources Information Center

Fawcett, Philip Earl

2017-01-01

The Center for Immigration Studies reported in October 2016 that immigration to the U.S. had reached historic numbers. According to the U.S. Census estimates, 59.1 million immigrants live in the U.S.; this numbers includes 16.7 million American-born children who are under the age of 18. Thus, approximately one in five U.S. residents is an…

Phoenix Union High School District #210 Adult Academy Evaluation Report, 1980-81. Research Services Report No. 33:08:80/81:010.

ERIC Educational Resources Information Center

Norris, Carol A.; Wheeler, Linda

The Adult Reading Academy, a federally-funded service of the Phoenix Union High School District, serves native- and foreign-born adult students who are deficient in the basic skills of reading, writing, arithmetic, and oral communication. In 1980/81, the program served 476 students at 17 sites. Approximately 24 percent of the clients served were…

The relative age effect reversal among the National Hockey League elite

PubMed Central

Gibbs, Benjamin G.; Jarvis, Jonathan A.; Rossi, Giambattista

2017-01-01

Like many sports in adolescence, junior hockey is organized by age groups. Typically, players born after December 31st are placed in the subsequent age cohort and as a result, will have an age advantage over those players born closer to the end of the year. While this relative age effect (RAE) has been well-established in junior hockey and other professional sports, the long-term impact of this phenomenon is not well understood. Using roster data on North American National Hockey League (NHL) players from the 2008–2009 season to the 2015–2016 season, we document a RAE reversal—players born in the last quarter of the year (October-December) score more and command higher salaries than those born in the first quarter of the year. This reversal is even more pronounced among the NHL “elite.” We find that among players in the 90th percentile of scoring, those born in the last quarter of the year score about 9 more points per season than those born in the first quarter. Likewise, elite players in the 90th percentile of salary who are born in the last quarter of the year earn 51% more pay than players born at the start of the year. Surprisingly, compared to players at the lower end of the performance distribution, the RAE reversal is about three to four times greater among elite players. PMID:28806751

Dyadic contrast function and quadratic forward model for radio frequency tomography

NASA Astrophysics Data System (ADS)

Picco, Vittorio

Radio Frequency Tomography is an underground imaging technology that aims to reconstruct extended, deeply buried objects such as tunnels or Underground Facilities (UGF). A network of sensors collects scattered electromagnetic field samples, which are processed to obtain 2D or 3D images of the complex dielectric permittivity profile of the volume under investigation. Unlike systems such as Synthetic Aperture Radar (SAR) or Ground Penetrating Radar (GPR) which normally employ wide-band pulses, RF Tomography uses Continuous Wave (CW) signals to illuminate the scene. The information about the target is not retrieved by relying on bandwidth but by exploiting spatial, frequency and/or polarization diversity. Interestingly, RF Tomography can be readily adapted to obtain images of targets in free space. In this context, in the Andrew Electromagnetics Laboratory of the University of Illinois at Chicago, a measurement system aimed to validate experimentally the performance of RF Tomography has been designed and built. Experimental data have been used to validate its forward model, different inversion algorithms, its performance in terms of resolution and the ability of the system to distinguish between metallic and non-metallic targets. In the specific case of imaging of metallic targets, this thesis proposes to extend the capabilities of RF Tomography by introducing a dyadic permittivity contrast. Electromagnetic scattering from a thin, wire-like object placed in free space with its main axis at an angle with respect to the incident electric field is studied. It is possible to show that for this configuration a fundamental difference exists between a metallic and a dielectric object. This phenomenon can be modeled into Maxwell's equations by using a dyadic permittivity contrast, as it is commonly done when studying crystals. As a result a new formulation of the RF Tomography forward model is obtained, based on a dyadic contrast function. Reconstruction of this dyad allows to estimate not only the location and shape, but also the spatial orientation of the target. In addition, this dissertation proposes an alternative modification of the forward model which removes some limitations caused by the Born approximation. Traditionally, the Born approximation is used to linearize the inherently non-linear forward model. This approximation is valid if the scatterer is small and does not interact strongly with other objects. A quadratic forward model represents a more correct formulation of the scattering phenomenon, and it allows to attempt quantitative reconstruction. Numerical results are presented to highlight the advantages that such a formulation provides over the Born approximation.

Investigation of Extensions to the Distorted Born Approximation in Strong Fluctuation Theory

DTIC Science & Technology

1988-10-01

9316I * where D = 3/4[bop+b# J+ l/4b;) D = 1/4[ bpp +bo | (35)n12 b -bo( I D 13 =l/ 2 [Cppzz +C4zzI n Here -1 0~ o , bus(z,z)= (271) u I dl )acs (zl) am...that FXW = 1- 2X + 32. + 1 2(X) = 2 - 23 + + ... (-5 F (X) = 2 3 3 42 3 ’ + VX +.. D5 F3 (X) = 2/X + 3 gn X + ... Using (D-4) and (D-5) as guides for...showed that the rational approximations to Fir F2, F3 have maximum errors of .06%, .03%, and .06%, respectively. The integrals in (C-5) are completely

Choice of phase in the CS and IOS approximation

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

Snider, R.F.

1982-04-01

With the recognition that the angular momentum representations of unit position and momentum directional states must have different but uniquely related phases, the previously presented expression of scattering amplitude in terms of IOS angle dependent phase shifts must be modified. This resolves a major disagreement between IOS and close coupled degeneracy averaged differential cross sections. It is found that the phase factors appearing in the differential cross section have nothing to do with any particular choice of decoupling parameter. As a consequence, the differential cross section is relatively insensitive to the choice of CS decoupling parameter. The phase relations obtainedmore » are also in agreement with those deduced from the Born approximation.« less

Radiative transfer theory for active remote sensing of a layer of small ellipsoidal scatterers. [of vegetation

NASA Technical Reports Server (NTRS)

Tsang, L.; Kubacsi, M. C.; Kong, J. A.

1981-01-01

The radiative transfer theory is applied within the Rayleigh approximation to calculate the backscattering cross section of a layer of randomly positioned and oriented small ellipsoids. The orientation of the ellipsoids is characterized by a probability density function of the Eulerian angles of rotation. The radiative transfer equations are solved by an iterative approach to first order in albedo. In the half space limit the results are identical to those obtained via the approach of Foldy's and distorted Born approximation. Numerical results of the theory are illustrated using parameters encountered in active remote sensing of vegetation layers. A distinctive characteristic is the strong depolarization shown by vertically aligned leaves.

Electron scattering intensities and Patterson functions of Skyrmions

NASA Astrophysics Data System (ADS)

Karliner, M.; King, C.; Manton, N. S.

2016-06-01

The scattering of electrons off nuclei is one of the best methods of probing nuclear structure. In this paper we focus on electron scattering off nuclei with spin and isospin zero within the Skyrme model. We consider two distinct methods and simplify our calculations by use of the Born approximation. The first method is to calculate the form factor of the spherically averaged Skyrmion charge density; the second uses the Patterson function to calculate the scattering intensity off randomly oriented Skyrmions, and spherically averages at the end. We compare our findings with experimental scattering data. We also find approximate analytical formulae for the first zero and first stationary point of a form factor.

Challenges in predicting climate and environmental effects on vector-borne disease episystems in a changing world.

PubMed

Tabachnick, W J

2010-03-15

Vector-borne pathogens cause enormous suffering to humans and animals. Many are expanding their range into new areas. Dengue, West Nile and Chikungunya have recently caused substantial human epidemics. Arthropod-borne animal diseases like Bluetongue, Rift Valley fever and African horse sickness pose substantial threats to livestock economies around the world. Climate change can impact the vector-borne disease epidemiology. Changes in climate will influence arthropod vectors, their life cycles and life histories, resulting in changes in both vector and pathogen distribution and changes in the ability of arthropods to transmit pathogens. Climate can affect the way pathogens interact with both the arthropod vector and the human or animal host. Predicting and mitigating the effects of future changes in the environment like climate change on the complex arthropod-pathogen-host epidemiological cycle requires understanding of a variety of complex mechanisms from the molecular to the population level. Although there has been substantial progress on many fronts the challenges to effectively understand and mitigate the impact of potential changes in the environment on vector-borne pathogens are formidable and at an early stage of development. The challenges will be explored using several arthropod-borne pathogen systems as illustration, and potential avenues to meet the challenges will be presented.

[Differential impact of social capital on mental health in the native-born and immigrant populations living in Catalonia (Spain)].

PubMed

Stoyanova, Alexandrina; Díaz-Serrano, Luis

2009-12-01

This study attempts to create a bridge between the literature on immigration and on social capital and health. The objectives were two-fold: firstly, to provide new empirical evidence on the association between social capital and health, using data from Catalonia for the first time and, secondly, to explore the possible existence of a differential impact of social capital on health between native-born residents and immigrants. We also distinguished between individual and community-level social capital. We used the 2006 Catalan Health Survey (ESCA 2006). To assess the relationship between social capital and mental health, we used multilevel models, estimated separately for native-born and immigrant residents. The results revealed a positive link between social capital and good mental health in Catalonia. However, this effect was stronger for individual than for community-level social capital. The results did not support the hypothesis of a differential impact between immigrants and native-born Catalans, but did indicate differences with respect to Spaniards born outside Catalonia. Geographic heterogeneity in the effect of individual social capital on mental health in both immigrants and native-born residents was also detected. We believe that enhancing social capital could potentially be an effective policy tool to achieve objectives related to health status improvement.

Congenital abnormalities in newborns of women with pregestational diabetes: A time-trend analysis, 1994 to 2009.

PubMed

Agha, Mohammad M; Glazier, Richard H; Moineddin, Rahim; Booth, Gillian

2016-10-01

The main objective of the current study is to examine the trend of congenital abnormalities among children born by women with and without diabetes, and to explore the impact of food fortification by folic acid on the rate of birth defects among these two groups of mothers. All children born alive in Ontario, Canada, during 1994 to 2009 and their mothers were included in study. Diagnosis of pregestational diabetes among mothers was identified using Diabetes registry, and diagnosis of birth defects among children were identified using hospital records. The prevalence of births among diabetic mothers increased by almost 200% during the study period. Among children born to mothers with diabetes, the prevalence for all anomalies combined was approximately 47% higher and for various cardiac and central nervous system anomalies up to a three- to fivefold higher than those born to nondiabetic mothers. While the rate of birth defects in both groups observed a considerable decline after food fortification in 1999, but the gap between two groups remained unchanged over time. While the prevalence of birth defects among diabetic pregnancies is still considerably higher that nondiabetic pregnancies, results of the current study indicate a declining trend in the prevalence of some congenital abnormalities among babies born to both diabetic and nondiabetic mothers after 1999. We need to be more aggressive in implementing preventive measures, including a national diabetes plan or the proposed universal policy of supra-dietary folic acid supplementation for women with diabetes who are of reproductive age. Birth Defects Research (Part A) 106:831-839, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Changing perspectives on marijuana use during early adolescence and young adulthood: Evidence from a panel of cross-sectional surveys.

PubMed

Salas-Wright, Christopher P; Vaughn, Michael G; Perron, Brian E; Gonzalez, Jennifer M Reingle; Goings, Trenette Clark

2016-12-01

Prior research has often overlooked potential cohort differences in marijuana views and use across adolescence and young adulthood. To begin to address this gap, we conduct an exploratory examination of marijuana views and use among American youth using a panel of cross-sectional surveys. Findings are based on repeated, cross-sectional data collected annually from adolescents (ages 12-17; n=230,452) and young adults (ages 18-21; n=120,588) surveyed as part of the National Survey on Drug Use and Health between 2002 and 2014. For each of the birth years between 1986 and 1996, we combined a series of nationally representative cross-sections to provide multi-year data strings designed to approximate nationally representative cohorts. Compared to youth born in the mid-to-late 1980s, youth born in the mid-1990s reported significantly higher levels of marijuana disapproval during the early adolescent years (Age 14: 1988=64.7%, 1994=70.4%) but lower levels of disapproval during the young adult years (Age 19: 1988=32.0%, 1994=25.0%; Age 20: 1988=27.9%, 1994=19.7%). Moreover, the prevalence of marijuana use among youth born in 1994 was significantly lower-compared to youth born in 1988-at age 14 (1988: 11.39%, 1994: 8.19%) and significantly higher at age 18 (1988: 29.67%, 1994: 34.83%). This pattern held even when adjusting for potential confounding by demographic changes in the population across the study period. We see evidence of changes in the perceptions of marijuana use among youth born during the late twentieth century. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Use of plastic bags to prevent hypothermia at birth in preterm infants--do they work at lower gestations?

PubMed

Ibrahim, C P H; Yoxall, C W

2009-02-01

Hypothermia at birth is strongly associated with mortality and morbidity in preterm infants. Occlusive wrapping of preterm infants during resuscitation, including polythene bags have been shown to prevent hypothermia. To evaluate the effectiveness of the introduction of polythene bags at resuscitation of infants born below 30 weeks gestation in a large tertiary neonatal centre. Retrospective audit of admission temperatures of all infants born below 30 weeks gestation for two years before and two years after the introduction of polythene bags. Hypothermia was defined as admission axillary temperature < 36 degrees C. A total of 334 eligible infants were born during the study period. Two hundred and fifty-three (75.8%) had admission temperatures recorded. The incidence of hypothermia fell from 25% to 16%(p = 0.098) for the whole group since the introduction of polythene bags. The main reduction in hypothermia was seen in infants born above 28 weeks gestation (19.4% vs. 3.9%, p = 0.017). There was no significant effect in infants born between 28 weeks and 30 weeks (29.3% vs. 24.8%, p = 0.58). Polythene bags are effective in reducing the incidence of hypothermia at admission in infants born below 30 weeks gestation. The benefit in infants born below 28 weeks gestation was only marginal. This is in contrast to previously published studies. This may be related to the comparatively low incidence of hypothermia at the study centre even prior to introduction of polythene bags.

Effectiveness of a flow-based device using riboflavin photochemistry in damaging blood-borne viral nucleic acids.

PubMed

Zhu, Liguo; Tong, Hongli; Wang, Shufang; Yu, Yang; Liu, Zhong; Li, Changqing; Wang, Deqing

2018-05-03

Effectiveness of a flow-based treatment device using riboflavin photochemistry was demonstrated by cytopathic effect method using indicator viruses. However, inactivation efficacy against real blood-borne viruses needs to be evaluated, especially at nucleic acid level. Special plasma samples with varying concentrations of blood-borne virus were selected using a strict blood selection procedure and were treated with device treatment (DT). Nucleic acid test (NAT) using polymerase chain reaction fluorescence method was used to detect virus copies. The NAT value of 4325 in plasma with high Hepatitis B Virus (HBV) concentrations decreased to 1330 with DT. After 100-fold dilution, the NAT value was below the NAT detection limits with DT compared with 23.0 that without DT. The NAT value of 61.9 in plasma with medium HBV concentrations decreased to 37.8 with DT, and after 10-fold dilution, the NAT value was below the NAT detection limits with DT compared with below 20 that without DT. The Ct values of plasma with low concentrations of blood-borne viruses were below the NAT detection limits with DT. There was a dose effect with DT which was effective in blood-borne viruses damaging nucleic acids to a level below the NAT detection limits. Copyright © 2018 Elsevier B.V. All rights reserved.

From ontology selection and semantic web to the integrated information system of food-borne diseases and food safety

USDA-ARS?s Scientific Manuscript database

Over the last three decades, the rapid explosion of information and resources on human food-borne diseases and food safety has provided the ability to rapidly determine and interpret the mechanisms of survival and pathogenesis of food-borne pathogens. However, several factors have hindered effective...

Mobilization of soil-borne arsenic by three common organic acids: Dosage and time effects.

PubMed

Onireti, Olaronke O; Lin, Chuxia

2016-03-01

A batch experiment was conducted to investigate the mobilization of soil-borne arsenic by three common low-molecular-weight organic acids with a focus on dosage and time effects. The results show that oxalic acid behaved differently from citric acid and malic acid in terms of mobilizing As that was bound to iron compounds. At an equivalent molar concentration, reactions between oxalic acid and soil-borne Fe were kinetically more favourable, as compared to those between either citric acid or malic acid and the soil-borne Fe. It was found that reductive dissolution of soil-borne Fe played a more important role in liberating As, as compared to non-reductive reactions. Prior to the 7th day of the experiment, As mobility increased with increasing dose of oxalic acid while there was no significant difference (P > 0.05) in mobilized As among the treatments with different doses of citric acid or malic acid. The dosage effect on soil-borne As mobilization in the citric acid and malic acid treatments became clear only after the 7th day of the experiment. Soluble Ca present in the soils could cause re-immobilization of As by competing with solution-borne Fe for available organic ligands to form practically insoluble organic compounds of calcium (i.e. calcium oxalate). This resulted in transformation of highly soluble organic complexes of iron (i.e. iron oxalate complexes) into slightly soluble organic compounds of iron (i.e. iron oxalate) or free ferric ion, which then reacted with the solution-borne arsenate ions to form practically insoluble iron arsenates in the latter part of the experiment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Association between pregnancy intention and optimal breastfeeding practices in the Philippines: a cross-sectional study1

PubMed Central

2012-01-01

Background The effect of pregnancy intention on post-natal practices like breastfeeding is still poorly understood in the Philippines. In this light, this study aims to determine the association between pregnancy intention and optimal breastfeeding practices in the Philippines. Methods This is a cross-sectional study design using the 2003 Philippine National Demographic and Health Survey. Logistic regression analysis was used to determine the independent association of pregnancy intention and optimal breastfeeding practices. The study includes 3,044 last-born children aged 6–36 months at the time of survey. Dead children were also included as long as their age of death satisfies the age criterion. Results Children born from mistimed pregnancies are more likely to have late breastfeeding initiation compared to children born from wanted pregnancies (OR = 1.44; 90%CI: 1.17-1.78). However, this occurs only among children belonging to households with low socio-economic status. Among children belonging to households with high socio-economic status, no significant effect of pregnancy intention on breastfeeding initiation was observed. Children born from unwanted pregnancies are less likely to have short breastfeeding duration (OR = 0.60; 90%CI: 0.48-0.76). However, this occurs only among children belonging to households with high socioeconomic status. No significant effect of pregnancy intention on breastfeeding duration was observed among children belonging to households with low socio-economic status. Conclusion The findings of this study suggest that there are different effects of pregnancy intention on the two types of optimal breastfeeding practices examined. With regards to breastfeeding duration, it was found that among infants belonging to high SES, the odds of having short breastfeeding duration is lower among children born from unwanted pregnancies compared to children born from wanted one. Conversely, children belonging to low SES household, the odds of having late breastfeeding initiation among children born from mistimed pregnancies are higher compared to children born from wanted pregnancies. PMID:22823890

Association between pregnancy intention and optimal breastfeeding practices in the Philippines: a cross-sectional study.

PubMed

Ulep, Valerie Gilbert T; Borja, Maridel P

2012-07-23

The effect of pregnancy intention on post-natal practices like breastfeeding is still poorly understood in the Philippines. In this light, this study aims to determine the association between pregnancy intention and optimal breastfeeding practices in the Philippines. This is a cross-sectional study design using the 2003 Philippine National Demographic and Health Survey. Logistic regression analysis was used to determine the independent association of pregnancy intention and optimal breastfeeding practices. The study includes 3,044 last-born children aged 6-36 months at the time of survey. Dead children were also included as long as their age of death satisfies the age criterion. Children born from mistimed pregnancies are more likely to have late breastfeeding initiation compared to children born from wanted pregnancies (OR = 1.44; 90%CI: 1.17-1.78). However, this occurs only among children belonging to households with low socio-economic status. Among children belonging to households with high socio-economic status, no significant effect of pregnancy intention on breastfeeding initiation was observed. Children born from unwanted pregnancies are less likely to have short breastfeeding duration (OR = 0.60; 90%CI: 0.48-0.76). However, this occurs only among children belonging to households with high socioeconomic status. No significant effect of pregnancy intention on breastfeeding duration was observed among children belonging to households with low socio-economic status. The findings of this study suggest that there are different effects of pregnancy intention on the two types of optimal breastfeeding practices examined. With regards to breastfeeding duration, it was found that among infants belonging to high SES, the odds of having short breastfeeding duration is lower among children born from unwanted pregnancies compared to children born from wanted one. Conversely, children belonging to low SES household, the odds of having late breastfeeding initiation among children born from mistimed pregnancies are higher compared to children born from wanted pregnancies.

Receipt of surgical treatment in US women with early stage breast cancer: does place of birth matter?

PubMed

Chavan, Saurabh; Goodman, Michael; Jemal, Ahmedin; Fedewa, Stacey A

2014-01-01

While effects of age, race, place of residence, and marital status on receipt of treatment among female breast cancer patients have been well documented, place of birth is a relatively less studied factor. The purpose of our study was to assess the relationship between birth place and type of surgery performed for early-stage breast cancer among US women of different racial and ethnic backgrounds. Eligible cases (n=119,560) were selected from the SEER registries for the period 2004-2009. US-born and foreign-born patients of different racial/ethnic groups were compared to US-born non-Hispanic Whites (NHW) with respect to receipt of breast conserving surgery (BCS) or mastectomy. Results of multivariable logistic regression analyses were expressed as adjusted odds ratios (OR) and the corresponding 95% confidence intervals (CI). The proportion of BCS was highest in foreign-born Whites (62.5%) and lowest in foreign-born Asians (50.3%). Relative to US-born NHW, BCS was more common in foreign-born Whites (OR=1.21. 95% CI: 1.15-1.28) and foreign-born Blacks (OR=1.21. 95% CI: 1.15-1.28). In contrast, foreign-born Asians received less BCS compared to both US-born NHW (OR=.76, 95% CI: .72-0.80) and US-born Asians (OR=.74, 95% CI: .64-.86). Foreign-born Asian breast cancer patients are less likely to receive BSC compared to US-born Whites or Asian-Americans, whereas foreign-born Whites and foreign-born Blacks are more likely to receive BCS than US-born Whites. Further studies are needed to understand cultural and or health systems factors that may explain these observations.

Immigration, stress, and depressive symptoms in a Mexican-American community.

PubMed

Golding, J M; Burnam, M A

1990-03-01

This study assessed levels of depressive symptomatology in a household probability sample of Mexico-born (N = 706) and U.S.-born (N = 538) Mexican Americans. We hypothesized that immigration status differences in acculturation, strain, social resources, and social conflict, as well as differences in the associations of these variables with depression, would account for differences in depression between U.S.-born and Mexico-born respondents. U.S.-born Mexican Americans had higher depression scores than those born in Mexico. When cultural and social psychological variables were controlled in a multiple regression analysis, the immigrant status difference persisted. Tests of interaction terms suggested greater vulnerability to the effects of low acculturation and low educational attainment among the U.S.-born relative to those born in Mexico; however, the immigrant status difference persisted after controlling for these interactions. Unmeasured variables such as selective migration of persons with better coping skills, selective return of depressed immigrants, or generational differences in social comparison processes may account for the immigration status difference.

Tick-Borne Zoonoses in the United States: Persistent and Emerging Threats to Human Health

PubMed Central

Eisen, Rebecca J.; Kugeler, Kiersten J.; Eisen, Lars; Beard, Charles B.; Paddock, Christopher D.

2017-01-01

In the United States, ticks transmit the greatest diversity of arthropod-borne pathogens and are responsible for the most cases of all vector-borne diseases. In recent decades, the number of reported cases of notifiable tick-borne diseases has steadily increased, geographic distributions of many ticks and tick-borne diseases have expanded, and new tick-borne disease agents have been recognized. In this review, we (1) describe the known disease agents associated with the most commonly human-biting ixodid ticks, (2) review the natural histories of these ticks and their associated pathogens, (3) highlight spatial and temporal changes in vector tick distributions and tick-borne disease occurrence in recent decades, and (4) identify knowledge gaps and barriers to more effective prevention of tick-borne diseases. We describe 12 major tick-borne diseases caused by 15 distinct disease agents that are transmitted by the 8 most commonly human-biting ixodid ticks in the United States. Notably, 40% of these pathogens were described within the last two decades. Our assessment highlights the importance of animal studies to elucidate how tick-borne pathogens are maintained in nature, as well as advances in molecular detection of pathogens which has led to the discovery of several new tick-borne disease agents. PMID:28369515

Electron-Impact Excitation of Ions Effects of Presence of Another Ion

NASA Astrophysics Data System (ADS)

Ohsaki, Akihiko; Nagasaki, Satoshi; Uramoto, Sei-iti; Takayanagi, Kazuo

2000-02-01

Present work gives for the first time the formulation of the two-center Coulomb-Born approximation (TCCBA) and presents some calculations for the electron-impact excitations in electron-ion-ion systems.The effect of the third body was relatively small in the cases studied so far. However, if the third body is a bare ion with a charge larger than the target ion, there will be a marked influence of the three-body collisions.Utilizing TCCBA we present the total and partial cross sections of hydrogen-like ions He+(Z=2), and C5+(Z=6) in the hydrogen plasma from the ground states 1s to the excited states 2s and 2p0, 2p± for the collision energies from 0.4Z2 to 2Z2 a.u.; for the excited states of the target ions, Stark effect is also studied.It is found that the presence of another ion have little effect on the 1s-2s transition and the 2s-2p Stark mixing has a prominent effect.

Future perspectives, applications and challenges of genomic epidemiology studies for food-borne pathogens: A case study of Enterohemorrhagic Escherichia coli (EHEC) of the O157:H7 serotype

PubMed Central

Eppinger, Mark; Cebula, Thomas A

2015-01-01

The shiga-toxin (Stx)-producing human pathogen Escherichia coli serotype O157:H7 is a highly pathogenic subgroup of Stx-producing E. coli (STEC) with food-borne etiology and bovine reservoir. Each year in the U. S., approximately 100,000 patients are infected with enterohemorrhagic E. coli (EHEC) of the O157:H7 serotype. This food-borne pathogen is a global public health threat responsible for widespread outbreaks of human disease. Since its initial discovery in 1982, O157:H7 has rapidly become the dominant EHEC serotype in North America. Hospitalization rates among patients as high as 50% have been reported for severe outbreaks of human disease. Symptoms of disease can rapidly deteriorate and progress to life-threatening complications such as Hemolytic Uremic Syndrome (HUS), the leading cause of kidney failure in children, or Hemorrhagic Colitis. In depth understanding of the genomic diversity that exists among currently circulating EHEC populations has broad applications for improved molecular-guided biosurveillance, outbreak preparedness, diagnostic risk assessment, and development of alternative toxin-suppressing therapeutics. PMID:25483335

Urbanization and human health in urban India: institutional analysis of water-borne diseases in Ahmedabad.

PubMed

Saravanan, V S; Ayessa Idenal, Marissa; Saiyed, Shahin; Saxena, Deepak; Gerke, Solvay

2016-10-01

Diseases are rapidly urbanizing. Ageing infrastructures, high levels of inequality, poor urban governance, rapidly growing economies and highly dense and mobile populations all create environments rife for water-borne diseases. This article analyzes the role of institutions as crosscutting entities among a myriad of factors that breed water-borne diseases in the city of Ahmedabad, India. It applies 'path dependency' and a 'rational choice' perspective to understand the factors facilitating the breeding of diseases. This study is based on household surveys of approximately 327 households in two case study wards and intermittent interviews with key informants over a period of 2 years. Principle component analysis is applied to reduce the data and convert a set of observations, which potentially correlate with each other, into components. Institutional analyses behind these components reveal the role of social actors in exploiting the deeply rooted inefficiencies affecting urban health. This has led to a vicious cycle; breaking this cycle requires understanding the political dynamics that underlie the exposure and prevalence of diseases to improve urban health. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Developmental outcomes of Japanese children born through Assisted Reproductive Technology (ART) in toddlerhood.

PubMed

Aoki, Sayaka; Hashimoto, Keiji; Ogawa, Kohei; Horikawa, Reiko; Sago, Haruhiko

2018-05-01

This study aimed to investigate developmental outcomes of Japanese babies born through Assisted Reproductive Technology (ART) at ages 2 and 3. The data were gathered from 1085 children in a hospital-based cohort study conducted in Japan. The children's level of development was assessed through a parent-rated questionnaire, the Kinder Infant Development Scale, which consists of nine developmental domains. We compared the development of children born through ART and those born naturally by conducting analyses of covariance. For the analyses, the effect of maternal age, family income, parental education and multiple birth were controlled for. At 24 months, no significant difference was found between children born through ART and those born naturally in development in any domain. At 36 months, a significant difference was found in development of Receptive language (F (1, 845) = 6.148, P = 0.013), Expressive language (F (1, 845) = 4.060, P = 0.044) and Language concept (F (1, 845) = 6.968, P = 0.008). For these domains, children born through ART had a significantly higher developmental age compared to children born naturally. At age 2, no significant difference was found between the children born through ART and those born naturally in nine developmental domains, although at age 3, the children born through ART showed significantly better language development than the children born naturally. © 2018 Japan Society of Obstetrics and Gynecology.

Climate change and the epidemiology of selected tick-borne and mosquito-borne diseases: update from the International Society of Dermatology Climate Change Task Force.

PubMed

Andersen, Louise K; Davis, Mark D P

2017-03-01

Climate change refers to variation in the climate of a specific region or globally over time. A change has been reported in the epidemiology of tick- and mosquito-borne diseases in recent decades. Investigators have postulated that this effect may be associated with climate change. We reviewed the English-language literature describing changes in the epidemiology of specific tick- and mosquito-borne diseases, including the tick-borne diseases of Lyme disease, tularemia, Crimean-Congo hemorrhagic fever, Mediterranean spotted fever, and Rocky Mountain spotted fever and the mosquito-borne diseases of dengue, malaria, West Nile virus infection, Ross River virus disease, and Barmah Forest virus disease. We postulate that the changing epidemiology of tick- and mosquito-borne diseases is related to climate change. © 2016 The International Society of Dermatology.

Theoretical investigation of two-particle two-hole effects on spin-isospin excitations through charge-exchange reactions

NASA Astrophysics Data System (ADS)

Fukui, Tokuro; Minato, Futoshi

2017-11-01

Background: Coherent one-particle one-hole (1p1h) excitations have given us effective insights into general nuclear excitations. However, the two-particle two-hole (2p2h) excitation beyond 1p1h is now recognized as critical for the proper description of experimental data of various nuclear responses. Purpose: The spin-flip charge-exchange reactions 48Ca(p ,n )48Sc are investigated to clarify the role of the 2p2h effect on their cross sections. The Fermi transition of 48Ca via the (p ,n ) reaction is also investigated in order to demonstrate our framework. Methods: The transition density is calculated microscopically with the second Tamm-Dancoff approximation, and the distorted-wave Born approximation is employed to describe the reaction process. A phenomenological one-range Gaussian interaction is used to prepare the form factor. Results: For the Fermi transition, our approach describes the experimental behavior of the cross section better than the Lane model, which is the conventional method. For spin-flip excitations including the GT transition, the 2p2h effect decreases the magnitude of the cross section and does not change the shape of the angular distribution. The Δ l =2 transition of the present reaction is found to play a negligible role. Conclusions: The 2p2h effect will not change the angular-distributed cross section of spin-flip responses. This is because the transition density of the Gamow-Teller response, the leading contribution to the cross section, is not significantly varied by the 2p2h effect.

Dyscalculia and the Calculating Brain.

PubMed

Rapin, Isabelle

2016-08-01

Dyscalculia, like dyslexia, affects some 5% of school-age children but has received much less investigative attention. In two thirds of affected children, dyscalculia is associated with another developmental disorder like dyslexia, attention-deficit disorder, anxiety disorder, visual and spatial disorder, or cultural deprivation. Infants, primates, some birds, and other animals are born with the innate ability, called subitizing, to tell at a glance whether small sets of scattered dots or other items differ by one or more item. This nonverbal approximate number system extends mostly to single digit sets as visual discrimination drops logarithmically to "many" with increasing numerosity (size effect) and crowding (distance effect). Preschoolers need several years and specific teaching to learn verbal names and visual symbols for numbers and school agers to understand their cardinality and ordinality and the invariance of their sequence (arithmetic number line) that enables calculation. This arithmetic linear line differs drastically from the nonlinear approximate number system mental number line that parallels the individual number-tuned neurons in the intraparietal sulcus in monkeys and overlying scalp distribution of discrete functional magnetic resonance imaging activations by number tasks in man. Calculation is a complex skill that activates both visual and spatial and visual and verbal networks. It is less strongly left lateralized than language, with approximate number system activation somewhat more right sided and exact number and arithmetic activation more left sided. Maturation and increasing number skill decrease associated widespread non-numerical brain activations that persist in some individuals with dyscalculia, which has no single, universal neurological cause or underlying mechanism in all affected individuals. Copyright © 2016 Elsevier Inc. All rights reserved.

Estimating the Gibbs energy of hydration from molecular dynamics trajectories obtained by integral equations of the theory of liquids in the RISM approximation

NASA Astrophysics Data System (ADS)

Tikhonov, D. A.; Sobolev, E. V.

2011-04-01

A method of integral equations of the theory of liquids in the reference interaction site model (RISM) approximation is used to estimate the Gibbs energy averaged over equilibrium trajectories computed by molecular mechanics. Peptide oxytocin is selected as the object of interest. The Gibbs energy is calculated using all chemical potential formulas introduced in the RISM approach for the excess chemical potential of solvation and is compared with estimates by the generalized Born model. Some formulas are shown to give the wrong sign of Gibbs energy changes when peptide passes from the gas phase into water environment; the other formulas give overestimated Gibbs energy changes with the right sign. Note that allowance for the repulsive correction in the approximate analytical expressions for the Gibbs energy derived by thermodynamic perturbation theory is not a remedy.

Reciprocal links among differential parenting, perceived partiality, and self-worth: a three-wave longitudinal study.

PubMed

Shebloski, Barbara; Conger, Katherine J; Widaman, Keith F

2005-12-01

This study examined reciprocal links between parental differential treatment, siblings' perception of partiality, and self-worth with 3 waves of data from 384 adolescent sibling dyads. Results suggest that birth-order status was significantly associated with self-worth and perception of maternal and paternal differential treatment. There was a consistent across-time effect of self-worth on perception of parental partiality for later born siblings, but not earlier born siblings, and a consistent effect of differential treatment on perception of partiality for earlier born but not later born siblings. The results contribute new insight into the associations between perception of differential parenting and adolescents' adjustment and the role of birth order. Copyright 2006 APA, all rights reserved).

Ad libitum Pasture Feeding in Late Pregnancy Does Not Improve the Performance of Twin-bearing Ewes and Their Lambs.

PubMed

Corner-Thomas, R A; Back, P J; Kenyon, P R; Hickson, R E; Ridler, A L; Stafford, K J; Morris, S T

2015-03-01

The present study evaluated the effect of controlled ryegrass-white clover herbage availability from day 128 until day 142 of pregnancy in comparison to unrestricted availability, on the performance of twin-bearing ewes of varying body condition score (BCS; 2.0, 2.5, or 3.0) and their lambs. It was hypothesised that under conditions of controlled herbage availability, the performance of lambs born to ewes with a greater BCS would be greater than those born to ewes with a lower BCS. During the period that the nutritional regimens were imposed, the pre- and post-grazing herbage masses of the Control regimen (1,070±69 and 801±30 kg dry matter [DM]/ha) were lower than the ad libitum regimen (1,784±69 and 1,333±33 kg DM/ha; p<0.05). The average herbage masses during lactation were 1,410±31 kg DM/ha. Nutritional regimen had no effect on ewe live weight, BCS and back fat depth or on lamb live weight, indices of colostrum uptake, maximal heat production, total litter weight weaned or survival to weaning (p>0.05). The difference in ewe BCSs and back fats observed among body condition groups was maintained throughout pregnancy (p<0.05). At weaning, ewes from the BCS2.0 group had lower BCS and live weight (2.4±0.2, 74.3±2.6 kg) than both the BCS2.5 (2.6±0.2, 78.6±2.4 kg) and BCS3.0 ewes (2.7±0.2, 79.0±2.6 kg; p<0.05), which did not differ (p>0.05). Ewe BCS group had no effect on lamb live weight at birth or weaning or on maximal heat production (p>0.05). Serum gamma glutamyl transferase concentrations of lambs born to BCS3.0 ewes were higher within 36 hours of birth than lambs born to BCS2.0 ewes and BCS2.5 ewes (51.8±1.9 vs 46.5±1.9 and 45.6±1.9 IU/mL, respectively [p<0.05]). There was, however, no effect of ewe body condition on lamb plasma glucose concentration (p>0.05). Lamb survival was the only lamb parameter that showed an interaction between ewe nutritional regimen and ewe BCS whereby survival of lambs born to BCS2.5 and BCS3.0 ewes differed but only within the Control nutritional regimen ewes (p<0.05). These results indicate farmers can provide twin-bearing ewes with pre- and post-grazing ryegrass-white clover herbage covers of approximately 1,100 and 800 kg DM/ha in late pregnancy, provided that herbage covers are 1400 in lactation, without affecting lamb performance to weaning. The present results also indicate that under these grazing conditions, there is little difference in ewe performance within the BCS range of 2.0 to 3.0 and therefore they do not need to be managed separately.

Ad libitum Pasture Feeding in Late Pregnancy Does Not Improve the Performance of Twin-bearing Ewes and Their Lambs

PubMed Central

Corner-Thomas, R. A.; Back, P. J.; Kenyon, P. R.; Hickson, R. E.; Ridler, A. L.; Stafford, K. J.; Morris, S. T.

2015-01-01

The present study evaluated the effect of controlled ryegrass-white clover herbage availability from day 128 until day 142 of pregnancy in comparison to unrestricted availability, on the performance of twin-bearing ewes of varying body condition score (BCS; 2.0, 2.5, or 3.0) and their lambs. It was hypothesised that under conditions of controlled herbage availability, the performance of lambs born to ewes with a greater BCS would be greater than those born to ewes with a lower BCS. During the period that the nutritional regimens were imposed, the pre- and post-grazing herbage masses of the Control regimen (1,070±69 and 801±30 kg dry matter [DM]/ha) were lower than the ad libitum regimen (1,784±69 and 1,333±33 kg DM/ha; p<0.05). The average herbage masses during lactation were 1,410±31 kg DM/ha. Nutritional regimen had no effect on ewe live weight, BCS and back fat depth or on lamb live weight, indices of colostrum uptake, maximal heat production, total litter weight weaned or survival to weaning (p>0.05). The difference in ewe BCSs and back fats observed among body condition groups was maintained throughout pregnancy (p<0.05). At weaning, ewes from the BCS2.0 group had lower BCS and live weight (2.4±0.2, 74.3±2.6 kg) than both the BCS2.5 (2.6±0.2, 78.6±2.4 kg) and BCS3.0 ewes (2.7±0.2, 79.0±2.6 kg; p<0.05), which did not differ (p>0.05). Ewe BCS group had no effect on lamb live weight at birth or weaning or on maximal heat production (p>0.05). Serum gamma glutamyl transferase concentrations of lambs born to BCS3.0 ewes were higher within 36 hours of birth than lambs born to BCS2.0 ewes and BCS2.5 ewes (51.8±1.9 vs 46.5±1.9 and 45.6±1.9 IU/mL, respectively [p<0.05]). There was, however, no effect of ewe body condition on lamb plasma glucose concentration (p>0.05). Lamb survival was the only lamb parameter that showed an interaction between ewe nutritional regimen and ewe BCS whereby survival of lambs born to BCS2.5 and BCS3.0 ewes differed but only within the Control nutritional regimen ewes (p<0.05). These results indicate farmers can provide twin-bearing ewes with pre- and post-grazing ryegrass-white clover herbage covers of approximately 1,100 and 800 kg DM/ha in late pregnancy, provided that herbage covers are 1400 in lactation, without affecting lamb performance to weaning. The present results also indicate that under these grazing conditions, there is little difference in ewe performance within the BCS range of 2.0 to 3.0 and therefore they do not need to be managed separately. PMID:25656209

Epidemiology of Tuberculosis in Young Children in the United States

PubMed Central

Pang, Jenny; Teeter, Larry D.; Katz, Dolly J.; Davidow, Amy L.; Miranda, Wilson; Wall, Kirsten; Ghosh, Smita; Stein-Hart, Trudy; Restrepo, Blanca I.; Reves, Randall; Graviss, Edward A.

2016-01-01

OBJECTIVES To estimate tuberculosis (TB) rates among young children in the United States by children’s and parents’ birth origins and describe the epidemiology of TB among young children who are foreign-born or have at least 1 foreign-born parent. METHODS Study subjects were children <5 years old diagnosed with TB in 20 US jurisdictions during 2005–2006. TB rates were calculated from jurisdictions’ TB case counts and American Community Survey population estimates. An observational study collected demographics, immigration and travel histories, and clinical and source case details from parental interviews and health department and TB surveillance records. RESULTS Compared with TB rates among US-born children with US-born parents, rates were 32 times higher in foreign-born children and 6 times higher in US-born children with foreign-born parents. Most TB cases (53%) were among the 29% of children who were US born with foreign-born parents. In the observational study, US-born children with foreign-born parents were more likely than foreign-born children to be infants (30% vs 7%), Hispanic (73% vs 37%), diagnosed through contact tracing (40% vs 7%), and have an identified source case (61% vs 19%); two-thirds of children were exposed in the United States. CONCLUSIONS Young children who are US born of foreign-born parents have relatively high rates of TB and account for most cases in this age group. Prompt diagnosis and treatment of adult source cases, effective contact investigations prioritizing young contacts, and targeted testing and treatment of latent TB infection are necessary to reduce TB morbidity in this population. PMID:24515517

Calculating pKa values for substituted phenols and hydration energies for other compounds with the first-order Fuzzy-Border continuum solvation model

PubMed Central

Sharma, Ity; Kaminski, George A.

2012-01-01

We have computed pKa values for eleven substituted phenol compounds using the continuum Fuzzy-Border (FB) solvation model. Hydration energies for 40 other compounds, including alkanes, alkenes, alkynes, ketones, amines, alcohols, ethers, aromatics, amides, heterocycles, thiols, sulfides and acids have been calculated. The overall average unsigned error in the calculated acidity constant values was equal to 0.41 pH units and the average error in the solvation energies was 0.076 kcal/mol. We have also reproduced pKa values of propanoic and butanoic acids within ca. 0.1 pH units from the experimental values by fitting the solvation parameters for carboxylate ion carbon and oxygen atoms. The FB model combines two distinguishing features. First, it limits the amount of noise which is common in numerical treatment of continuum solvation models by using fixed-position grid points. Second, it employs either second- or first-order approximation for the solvent polarization, depending on a particular implementation. These approximations are similar to those used for solute and explicit solvent fast polarization treatment which we developed previously. This article describes results of employing the first-order technique. This approximation places the presented methodology between the Generalized Born and Poisson-Boltzmann continuum solvation models with respect to their accuracy of reproducing the many-body effects in modeling a continuum solvent. PMID:22815192

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

Will integrated surveillance systems for vectors and vector-borne diseases be the future of controlling vector-borne diseases? A practical example from China.

PubMed

Wu, Y; Ling, F; Hou, J; Guo, S; Wang, J; Gong, Z

2016-07-01

Vector-borne diseases are one of the world's major public health threats and annually responsible for 30-50% of deaths reported to the national notifiable disease system in China. To control vector-borne diseases, a unified, effective and economic surveillance system is urgently needed; all of the current surveillance systems in China waste resources and/or information. Here, we review some current surveillance systems and present a concept for an integrated surveillance system combining existing vector and vector-borne disease monitoring systems. The integrated surveillance system has been tested in pilot programmes in China and led to a 21·6% cost saving in rodent-borne disease surveillance. We share some experiences gained from these programmes.

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.

Application of a Protocol Based on Trap-Neuter-Return (TNR) to Manage Unowned Urban Cats on an Australian University Campus.

PubMed

Swarbrick, Helen; Rand, Jacquie

2018-05-17

In August 2008, the University of New South Wales (UNSW) in Sydney, Australia, commenced a trap-neuter-return (TNR) program to manage the population of approximately 69 free-roaming unowned urban cats on its Kensington campus. The goals of the program included an ongoing audit of cats on campus, stabilization of cat numbers through TNR, and a subsequent reduction in cat numbers over time while maintaining the health of remaining campus cats. Continuation of the TNR program over nine years resulted in a current population, as of September 2017, of 15 cats, all desexed (78% reduction). Regular monitoring of the cats through a daily feeding program identified a further 34 cats that immigrated on to campus since initiation of the program; these comprised 28 adult cats (16 unsocialized, 12 socialized) and six solitary kittens. In addition, 19 kittens were born on campus, 14 of which were born to immigrant pregnant females. Unsocialized adult immigrants were absorbed into the resident campus population. Where possible, socialized adult immigrants, solitary kittens, and campus-born kittens were removed from campus through rehoming. Overall, reasons for reductions in the cat population (original residents, immigrants, campus-born kittens; n = 122) included rehoming or return to owner (30%), death/euthanasia (30%) and disappearance (29%). This successful animal management program received some initial funding from the university to support desexing, but was subsequently funded through donations, and continues with the university's approval and support.

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.

Interpreting the Coulomb-field approximation for generalized-Born electrostatics using boundary-integral equation theory.

PubMed

Bardhan, Jaydeep P

2008-10-14

The importance of molecular electrostatic interactions in aqueous solution has motivated extensive research into physical models and numerical methods for their estimation. The computational costs associated with simulations that include many explicit water molecules have driven the development of implicit-solvent models, with generalized-Born (GB) models among the most popular of these. In this paper, we analyze a boundary-integral equation interpretation for the Coulomb-field approximation (CFA), which plays a central role in most GB models. This interpretation offers new insights into the nature of the CFA, which traditionally has been assessed using only a single point charge in the solute. The boundary-integral interpretation of the CFA allows the use of multiple point charges, or even continuous charge distributions, leading naturally to methods that eliminate the interpolation inaccuracies associated with the Still equation. This approach, which we call boundary-integral-based electrostatic estimation by the CFA (BIBEE/CFA), is most accurate when the molecular charge distribution generates a smooth normal displacement field at the solute-solvent boundary, and CFA-based GB methods perform similarly. Conversely, both methods are least accurate for charge distributions that give rise to rapidly varying or highly localized normal displacement fields. Supporting this analysis are comparisons of the reaction-potential matrices calculated using GB methods and boundary-element-method (BEM) simulations. An approximation similar to BIBEE/CFA exhibits complementary behavior, with superior accuracy for charge distributions that generate rapidly varying normal fields and poorer accuracy for distributions that produce smooth fields. This approximation, BIBEE by preconditioning (BIBEE/P), essentially generates initial guesses for preconditioned Krylov-subspace iterative BEMs. Thus, iterative refinement of the BIBEE/P results recovers the BEM solution; excellent agreement is obtained in only a few iterations. The boundary-integral-equation framework may also provide a means to derive rigorous results explaining how the empirical correction terms in many modern GB models significantly improve accuracy despite their simple analytical forms.

A flexible Bayesian hierarchical model of preterm birth risk among US Hispanic subgroups in relation to maternal nativity and education

PubMed Central

2011-01-01

Background Previous research has documented heterogeneity in the effects of maternal education on adverse birth outcomes by nativity and Hispanic subgroup in the United States. In this article, we considered the risk of preterm birth (PTB) using 9 years of vital statistics birth data from New York City. We employed finer categorizations of exposure than used previously and estimated the risk dose-response across the range of education by nativity and ethnicity. Methods Using Bayesian random effects logistic regression models with restricted quadratic spline terms for years of completed maternal education, we calculated and plotted the estimated posterior probabilities of PTB (gestational age < 37 weeks) for each year of education by ethnic and nativity subgroups adjusted for only maternal age, as well as with more extensive covariate adjustments. We then estimated the posterior risk difference between native and foreign born mothers by ethnicity over the continuous range of education exposures. Results The risk of PTB varied substantially by education, nativity and ethnicity. Native born groups showed higher absolute risk of PTB and declining risk associated with higher levels of education beyond about 10 years, as did foreign-born Puerto Ricans. For most other foreign born groups, however, risk of PTB was flatter across the education range. For Mexicans, Central Americans, Dominicans, South Americans and "Others", the protective effect of foreign birth diminished progressively across the educational range. Only for Puerto Ricans was there no nativity advantage for the foreign born, although small numbers of foreign born Cubans limited precision of estimates for that group. Conclusions Using flexible Bayesian regression models with random effects allowed us to estimate absolute risks without strong modeling assumptions. Risk comparisons for any sub-groups at any exposure level were simple to calculate. Shrinkage of posterior estimates through the use of random effects allowed for finer categorization of exposures without restricting joint effects to follow a fixed parametric scale. Although foreign born Hispanic women with the least education appeared to generally have low risk, this seems likely to be a marker for unmeasured environmental and behavioral factors, rather than a causally protective effect of low education itself. PMID:21504612

A flexible Bayesian hierarchical model of preterm birth risk among US Hispanic subgroups in relation to maternal nativity and education.

PubMed

Kaufman, Jay S; MacLehose, Richard F; Torrone, Elizabeth A; Savitz, David A

2011-04-19

Previous research has documented heterogeneity in the effects of maternal education on adverse birth outcomes by nativity and Hispanic subgroup in the United States. In this article, we considered the risk of preterm birth (PTB) using 9 years of vital statistics birth data from New York City. We employed finer categorizations of exposure than used previously and estimated the risk dose-response across the range of education by nativity and ethnicity. Using Bayesian random effects logistic regression models with restricted quadratic spline terms for years of completed maternal education, we calculated and plotted the estimated posterior probabilities of PTB (gestational age < 37 weeks) for each year of education by ethnic and nativity subgroups adjusted for only maternal age, as well as with more extensive covariate adjustments. We then estimated the posterior risk difference between native and foreign born mothers by ethnicity over the continuous range of education exposures. The risk of PTB varied substantially by education, nativity and ethnicity. Native born groups showed higher absolute risk of PTB and declining risk associated with higher levels of education beyond about 10 years, as did foreign-born Puerto Ricans. For most other foreign born groups, however, risk of PTB was flatter across the education range. For Mexicans, Central Americans, Dominicans, South Americans and "Others", the protective effect of foreign birth diminished progressively across the educational range. Only for Puerto Ricans was there no nativity advantage for the foreign born, although small numbers of foreign born Cubans limited precision of estimates for that group. Using flexible Bayesian regression models with random effects allowed us to estimate absolute risks without strong modeling assumptions. Risk comparisons for any sub-groups at any exposure level were simple to calculate. Shrinkage of posterior estimates through the use of random effects allowed for finer categorization of exposures without restricting joint effects to follow a fixed parametric scale. Although foreign born Hispanic women with the least education appeared to generally have low risk, this seems likely to be a marker for unmeasured environmental and behavioral factors, rather than a causally protective effect of low education itself.

A measurement of the relative cross sections for simultaneous ionization and excitation of the degenerate He(plus) n equals 4 levels

NASA Technical Reports Server (NTRS)

Sutton, J. F.; Kay, R. B.

1972-01-01

The relative cross sections for simultaneous ionization and excitation of helium by 200 eV electrons into the 4S, 4P, 4D and 4F levels have been measured via a fast delayed coincidence technique. Results are in poor agreement with Born approximation calculations for simultaneous ionization and excitation of helium, the 4P component being larger than expected.

Tilting-filter measurements in dayglow rocket photometry.

PubMed

Schaeffer, R C; Fastie, W G

1972-10-01

A rocket-borne photometer containing two tilting-filter channels for the measurement of the [OI] lambdalambda6300-A and 5577A emission lines in the day airglow is described. The results of one flight substantiate the employment of tilting filters to determine accurate corrections for background continuum and provide reliable height profiles of emission intensity down to approximately 90 km. Discussions on the calibration of the instrument and its baffling against sunlight are also presented.

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

ERIC Educational Resources Information Center

Wyatt, Laura C.; Trinh-Shevrin, Chau; Islam, Nadia S.; Kwon, Simona C.

2014-01-01

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…

Prevalence of direct-reaction mechanism in a deeply inelastic reaction, /sup 197/Au(/sup 19/F,/sup 12/B)

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

Ishihara, M.; Shimoda, T.; Froehlich, H.

1979-07-09

Continuum cross sections and spin polarizations of /sup 12/B produced in the reaction /sup 197/Au(/sup 19/F,/sup 12/B) induced by 186-MeV/sup 19/F were measured. The observed data were reproduced very well in terms of a distorted-wave Born-approximation theory, indicating that this reaction transferring as many as seven nucleons proceeds as a direct process.

Smoking Trends among U.S. Latinos, 1998–2013: The Impact of Immigrant Arrival Cohort

PubMed Central

Bostean, Georgiana; Ro, Annie; Fleischer, Nancy L.

2017-01-01

Few studies examine nativity disparities in smoking in the U.S., thus a major gap remains in understanding whether immigrant Latinos’ smoking prevalence is stable, converging, or diverging, compared with U.S.-born Latinos. This study aimed to disentangle the roles of period changes, duration of U.S. residence, and immigrant arrival cohort in explaining the gap in smoking prevalence between foreign-born and U.S.-born Latinos. Using repeated cross-sectional data spanning 1998–2013 (U.S. National Health Interview Survey), regressions predicted current smoking among foreign-born and U.S.-born Latino men and women (n = 12,492). We contrasted findings from conventional regression analyses that simply include period and duration of residence effects, to two methods of assessing arrival cohort effects: the first accounted for baseline differences in smoking among arrival cohorts, while the second examined smoking probabilities by tracking foreign-born arrival cohorts as they increase their duration of U.S. residence. Findings showed that Latino immigrants maintained lower prevalence of current smoking compared with U.S.-born Latinos over the period 1998–2013, and that longer duration of U.S. residence is associated with lower odds of smoking among men. Two findings are particularly novel: (1) accounting for immigrant arrival cohort dampens the overall protective effect of duration of residence among men; and (2) the earliest arrival cohort of Latino immigrant men experienced the steepest decline in smoking over duration of U.S. residence. Results have methodological and theoretical implications for smoking studies and the Latino mortality paradox. PMID:28257125

Relative Age Effects on Physical Education Attainment and School Sport Representation

ERIC Educational Resources Information Center

Cobley, Stephen; Abraham, Colin; Baker, Joseph

2008-01-01

Background: The "Relative Age Effect" (RAE) has consistently been demonstrated to influence attainment in various contexts. In education, RAE appears to provide an advantage to those born during initial months of an academic year, compared with those born in later months. A similar effect has been noted in many sports, with those born…

Reduced rotavirus vaccine effectiveness among children born during the rotavirus season: a pooled analysis of 5 case-control studies from the Americas.

PubMed

Premkumar, Prasanna S; Parashar, Umesh D; Gastanaduy, Paul A; McCracken, John P; de Oliveira, Lucia Helena; Payne, Daniel C; Patel, Manish M; Tate, Jacqueline E; Lopman, Ben A

2015-04-01

Using data from rotavirus vaccine effectiveness (VE) studies, we assessed whether rotavirus season modifies rotavirus VE in infants. In the first year of life, adjusted VE was 72% for children born during rotavirus season and 84% for children born in other months (P = .01). Seasonal factors may interfere with vaccine performance. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Assimilating Foreign-Born Employees into Organizations through Effective Orientation Programs.

ERIC Educational Resources Information Center

Stull, James B.; And Others

Since research suggests that a direct relationship exists between effective orientation and employee productivity, careful consideration must be given to content, design, and delivery issues when developing orientation training programs for foreign-born employees. The United States typically does not provide adequate employee orientation.…

Are immigrants healthier than native-born Canadians? A systematic review of the healthy immigrant effect in Canada.

PubMed

Vang, Zoua M; Sigouin, Jennifer; Flenon, Astrid; Gagnon, Alain

2017-06-01

Immigrants are typically healthier than the native-born population in the receiving country and also tend to be healthier than non-migrants in the countries of origin. This foreign-born health advantage has been referred to as the healthy immigrant effect (HIE). We examined evidence for the HIE in Canada. We employed a systematic search of the literature on immigration and health and identified 78 eligible studies. We used a narrative method to synthesize the HIE across different stages of the life-course and different health outcomes within each stage. We also examined the empirical evidence for positive selection and duration effects - two common explanations of migrants' health advantage and deterioration, respectively. We find that the HIE appears to be strongest during adulthood but less so during childhood/adolescence and late life. A foreign-born health advantage is also more robust for mortality but less so for morbidity. The HIE is also stronger for more recent immigrants but further research is needed to determine the critical threshold for when migrants' advantage disappears. Positive selection as an explanation for the HIE remains underdeveloped. There is an absence of a uniform foreign-born health advantage across different life-course stages and health outcomes in Canada. Nonetheless, it remains the case that the HIE characterizes the majority of contemporary migrants since Canada's foreign-born population consists mostly of core working age adults.

Cubic Calorimeter for High-Energy Electrons in Ultra-Long Ballooning

NASA Technical Reports Server (NTRS)

Moiseev, Alexander A.; Mitchell, John W.; Ormes, Jonathan F.; Streitmatter, Robert E.

2003-01-01

The concept and optimization study of a balloon-borne instrument to study high-energy (from 100 GeV to 5 TeV) cosmic ray electrons will be presented. This energy range of electrons is very interesting for the study of cosmic ray propagation and the search for the nearby sources of high-energy electrons. The instrument is based on a cubic design that allows the detection from all sides. Proton rejection is provided by stringent track analysis, which allows defining when an electron shower is exhausted while the hadron shower continues development. The collecting power of a nominal balloon-borne instrument using this concept will be over 2 square meters sr. This will provide approximately 3,000 electron events above 500 GeV for 3-month long ULDB flight. This instrument will also be capable of detecting sharp features in the high energy gamma-ray spectrum such as gamma-ray lines originating from the dark matter annihilation.

Culicoides variipennis and bluetongue-virus epidemiology in the United States.

PubMed

Tabachnick, W J

1996-01-01

The bluetongue viruses are transmitted to ruminants in North America by Culicoides variipennis. US annual losses of approximately $125 million are due to restrictions on the movement of livestock and germplasm to bluetongue-free countries. Bluetongue is the most economically important arthropod-borne animal disease in the United States. Bluetongue is absent in the northeastern United States because of the inefficient vector ability there of C. variipennis for bluetongue. The vector of bluetongue virus elsewhere in the United States is C. variipennis sonorensis. The three C. variipennis subspecies differ in vector competence for bluetongue virus in the laboratory. Understanding C. variipennis genetic variation controlling bluetongue transmission will help identify geographic regions at risk for bluetongue and provide opportunities to prevent virus transmission. Information on C. variipennis and bluetongue epidemiology will improve trade and provide information to protect US livestock from domestic and foreign arthropod-borne pathogens.

Lidar- and balloon-borne particle counter comparisons following recent volcanic eruptions

NASA Technical Reports Server (NTRS)

Hofmann, D. J.; Rosen, J. M.; Reiter, R.; Jager, H.

1983-01-01

Balloon-borne particle counter measurements at Laramie, Wyoming (41 deg N) are used to calculate the expected lidar backscatter at 0.694 micron wavelength from July 1979 to February 1982, a period which included at least four detectable perturbations of the stratospheric aerosol layer due to volcanic eruptions. These calculations are compared with lidar measurements conducted at Garmisch-Partenkirchen (47.5 deg N) during the same period. While the agreement is generally good using only the main mode in the particle size distribution (radius about 0.07 micron) during approximately the first 6 months following a major volcanic eruption, a measured secondary mode near 1 micron radius, when included, improves the agreement. Calculations of the expected backscatter at 25-30 km reveal that substantial number of particles diffuse into this high altitude region about 7 months after a major eruption, and these particles should be taken into account when normalizing lidar at these altitudes.

"Know More Hepatitis:" CDC's National Education Campaign to Increase Hepatitis C Testing Among People Born Between 1945 and 1965.

PubMed

Jorgensen, Cynthia; Carnes, C Amanda; Downs, Alycia

2016-01-01

In 2012, CDC issued recommendations calling for those born between 1945 and 1965, or baby boomers, to get tested for the hepatitis C virus. To help implement this recommendation, CDC developed "Know More Hepatitis," a multimedia national education campaign. Guided by behavioral science theories and formative research, the campaign used multiple strategies to reach baby boomers and health-care providers with messages encouraging baby boomers to get tested for hepatitis C. With a limited campaign budget, the "Know More Hepatitis" campaign relied mostly on donated time and space from broadcast and print outlets. Donated placements totaled approximately $14.7 million, which reflected a more than 12-to-1 return on the campaign investment. This effort was supplemented with a small, paid digital advertising campaign. Combining audience impressions from both paid and donated campaign efforts resulted in more than 1.2 billion audience impressions.

The Role of Clinics in Determining Older Recent Immigrants' Use of Health Services.

PubMed

Vega, Alma; Porteny, Thalia; Aguila, Emma

2018-01-30

Immigrants are ineligible for federally-funded Medicaid in the U.S. until at least 5 years after arrival. There is little information on where they receive care in light of this restriction. Using Blinder-Oaxaca decomposition, this study examines whether the setting in which older recent immigrants receive care (i.e., health clinic, emergency room or doctor's office) explains delays in care. Among older adults with a usual source of care, 13.5% of recent immigrants had not seen a health professional in the past year compared to 8.6% of non-recent immigrants and 6.3% of native-born. Approximately 23% of these differences is attributable to recent immigrants' tendency to receive care in clinics and community health centers. Even when older recent immigrants manage to find a usual source of care, it is of lower quality than that received by their non-recent immigrant and native-born counterparts.

A rigorous approach to the formulation of extended Born-Oppenheimer equation for a three-state system

NASA Astrophysics Data System (ADS)

Sarkar, Biplab; Adhikari, Satrajit

If a coupled three-state electronic manifold forms a sub-Hilbert space, it is possible to express the non-adiabatic coupling (NAC) elements in terms of adiabatic-diabatic transformation (ADT) angles. Consequently, we demonstrate: (a) Those explicit forms of the NAC terms satisfy the Curl conditions with non-zero Divergences; (b) The formulation of extended Born-Oppenheimer (EBO) equation for any three-state BO system is possible only when there exists coordinate independent ratio of the gradients for each pair of ADT angles leading to zero Curls at and around the conical intersection(s). With these analytic advancements, we formulate a rigorous EBO equation and explore its validity as well as necessity with respect to the approximate one (Sarkar and Adhikari, J Chem Phys 2006, 124, 074101) by performing numerical calculations on two different models constructed with different chosen forms of the NAC elements.

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.

The Impact of Early Intervention on the School Readiness of Children Born to Teenage Mothers

ERIC Educational Resources Information Center

Brown, Amber L.

2015-01-01

This study examined the effect of participation in the Home Instruction for Parents of Preschool Youngsters program on the school readiness of children born to teenage mothers versus children born to traditional-age mothers participating in the Home Instruction for Parents of Preschool Youngsters program. A 45-item survey was collected from the…