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Sample records for born-oppenheimer approximation

  1. On the mathematical treatment of the Born-Oppenheimer approximation

    International Nuclear Information System (INIS)

    Jecko, Thierry

    2014-01-01

    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 use 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

  2. On the mathematical treatment of the Born-Oppenheimer approximation

    Energy Technology Data Exchange (ETDEWEB)

    Jecko, Thierry, E-mail: thierry.jecko@u-cergy.fr [AGM, UMR 8088 du CNRS, Université de Cergy-Pontoise, Département de mathématiques, site de Saint Martin, 2 avenue Adolphe Chauvin, F-95000 Pontoise (France)

    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 use 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.

  3. Muonic-hydrogen molecular bound states, quasibound states, and resonances in the Born-Oppenheimer approximation

    International Nuclear Information System (INIS)

    Jackson, J.D.

    1994-01-01

    The Born-Oppenheimer approximation is used as an exploratory tool to study bound states, quasibound states, and scattering resonances in muon (μ)--hydrogen (x)--hydrogen (y) molecular ions. Our purpose is to comment on the existence and nature of the narrow states reported in three-body calculations, for L=0 and 1, at approximately 55 eV above threshold and the family of states in the same partial waves reported about 1.9 keV above threshold. We first discuss the motivation for study of excited states beyond the well-known and well-studied bound states. Then we reproduce the energies and other properties of these well-known states to show that, despite the relatively large muon mass, the Born-Oppenheimer approximation gives a good, semiquantitative description containing all the essential physics. Born-Oppenheimer calculations of the s- and p-wave scattering of d-(dμ), d-(tμ), and t-(tμ) are compared with the accurate three-body results, again with general success. The places of disagreement are understood in terms of the differences in location of slightly bound (or unbound) states in the Born-Oppenheimer approximation compared to the accurate three-body calculations

  4. The AC Stark Effect, Time-Dependent Born-Oppenheimer Approximation, and Franck-Condon Factors

    CERN Document Server

    Hagedorn, G A; Jilcott, S W

    2005-01-01

    We study the quantum mechanics of a simple molecular system that is subject to a laser pulse. We model the laser pulse by a classical oscillatory electric field, and we employ the Born--Oppenheimer approximation for the molecule. We compute transition amplitudes to leading order in the laser strength. These amplitudes contain Franck--Condon factors that we compute explicitly to leading order in the Born--Oppenheimer parameter. We also correct an erroneous calculation in the mathematical literature on the AC Stark effect for molecular systems.

  5. Thermostating extended Lagrangian Born-Oppenheimer molecular dynamics.

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    Stottmeister, Alexander; Thiemann, Thomas

    2016-01-01

    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, 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).

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Arne Scherrer

    2017-08-01

    Full Text Available 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

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

    Science.gov (United States)

    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.

  10. Energy conserving, linear scaling Born-Oppenheimer molecular dynamics.

    Science.gov (United States)

    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.

  11. Wave equation of a nonlinear triatomic molecule and the adiabatic correction to the Born--Oppenheimer approximation

    International Nuclear Information System (INIS)

    Bardo, R.D.; Wolfsberg, M.

    1977-01-01

    The wave equation for a nonlinear polyatomic molecule is formulated in molecule-fixed coordinates by a method originally due to Hirschfelder and Wigner. Application is made to a triatomic molecule, and the wave equation is explicitly presented in a useful molecule-fixed coordinate system. The formula for the adiabatic correction to the Born--Oppenheimer approximation for a triatomic molecule is obtained. The extension of the present formulation to larger polyatomic molecules is pointed out. Some terms in the triatomic molecule wave equation are discussed in detail

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

    Science.gov (United States)

    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.

  13. Does really Born-Oppenheimer approximation break down in charge transfer processes? An exactly solvable model

    International Nuclear Information System (INIS)

    Kuznetsov, Alexander M.; Medvedev, Igor G.

    2006-01-01

    Effects of deviation from the Born-Oppenheimer approximation (BOA) on the non-adiabatic transition probability for the transfer of a quantum particle in condensed media are studied within an exactly solvable model. The particle and the medium are modeled by a set of harmonic oscillators. The dynamic interaction of the particle with a single local mode is treated explicitly without the use of BOA. Two particular situations (symmetric and non-symmetric systems) are considered. It is shown that the difference between the exact solution and the true BOA is negligibly small at realistic parameters of the model. However, the exact results differ considerably from those of the crude Condon approximation (CCA) which is usually considered in the literature as a reference point for BOA (Marcus-Hush-Dogonadze formula). It is shown that the exact rate constant can be smaller (symmetric system) or larger (non-symmetric one) than that obtained in CCA. The non-Condon effects are also studied

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

    Science.gov (United States)

    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.

  15. A Time--Independent Born--Oppenheimer Approximation with Exponentially Accurate Error Estimates

    CERN Document Server

    Hagedorn, G A

    2004-01-01

    We consider a simple molecular--type quantum system in which the nuclei have one degree of freedom and the electrons have two levels. The Hamiltonian has the form \\[ H(\\epsilon)\\ =\\ -\\,\\frac{\\epsilon^4}2\\, \\frac{\\partial^2\\phantom{i}}{\\partial y^2}\\ +\\ h(y), \\] where $h(y)$ is a $2\\times 2$ real symmetric matrix. Near a local minimum of an electron level ${\\cal E}(y)$ that is not at a level crossing, we construct quasimodes that are exponentially accurate in the square of the Born--Oppenheimer parameter $\\epsilon$ by optimal truncation of the Rayleigh--Schr\\"odinger series. That is, we construct $E_\\epsilon$ and $\\Psi_\\epsilon$, such that $\\|\\Psi_\\epsilon\\|\\,=\\,O(1)$ and \\[ \\|\\,(H(\\epsilon)\\,-\\,E_\\epsilon))\\,\\Psi_\\epsilon\\,\\|\\ 0. \\

  16. Analysis of Time Reversible Born-Oppenheimer Molecular Dynamics

    Directory of Open Access Journals (Sweden)

    Lin Lin

    2013-12-01

    Full Text Available We analyze the time reversible Born-Oppenheimer molecular dynamics (TRBOMD scheme, which preserves the time reversibility of the Born-Oppenheimer molecular dynamics even with non-convergent self-consistent field iteration. In the linear response regime, we derive the stability condition, as well as the accuracy of TRBOMD for computing physical properties, such as the phonon frequency obtained from the molecular dynamics simulation. We connect and compare TRBOMD with Car-Parrinello molecular dynamics in terms of accuracy and stability. We further discuss the accuracy of TRBOMD beyond the linear response regime for non-equilibrium dynamics of nuclei. Our results are demonstrated through numerical experiments using a simplified one-dimensional model for Kohn-Sham density functional theory.

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

    Science.gov (United States)

    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.

  18. Quantum Chemistry beyond Born–Oppenheimer Approximation on a Quantum Computer: A Simulated Phase Estimation Study

    Czech Academy of Sciences Publication Activity Database

    Veis, Libor; Višňák, Jakub; Nishizawa, H.; Nakai, H.; Pittner, Jiří

    2016-01-01

    Roč. 116, č. 18 (2016), s. 1328-1336 ISSN 0020-7608 R&D Projects: GA ČR GA203/08/0626 Institutional support: RVO:61388955 Keywords : Born-Oppenheimer approximation * nuclear orbital plus molecular orbital method * phase estimation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.920, year: 2016

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

    Science.gov (United States)

    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).

  20. Lowest vibrational states of 4He3He+: Non-Born-Oppenheimer calculations

    International Nuclear Information System (INIS)

    Stanke, Monika; Bubin, Sergiy; Kedziera, Dariusz; Molski, Marcin; Adamowicz, Ludwik

    2007-01-01

    Very accurate quantum mechanical calculations of the first five vibrational states of the 4 He 3 He + molecular ion are reported. The calculations have been performed explicitly including the coupling of the electronic and nuclear motions [i.e., without assuming the Born-Oppenheimer (BO) approximation]. The nonrelativistic non-BO wave functions were used to calculate the α 2 relativistic mass velocity, Darwin, and spin-spin interaction corrections. For the lowest vibrational transition, whose experimental energy is established with high precision, the calculated and the experimental results differ by only 0.16 cm -1

  1. Born-Oppenheimer description of two atoms in a combined oscillator and lattice trap

    DEFF Research Database (Denmark)

    Sørensen, Ole Søe; Mølmer, Klaus

    2012-01-01

    We analyze the quantum states of two identical bosons in a combined harmonic oscillator and periodic lattice trap in one spatial dimension. In the case of tight-binding and only nearest-neighbor tunneling, the equations of motion are conveniently represented in the momentum representation. We sho...... that in the case of strong attraction between the particles, the different time scales of relative and center-of-mass motions validate a separation of the problem similar to the Born-Oppenheimer approximation applied in the description of electronic and nuclear motions in molecules....

  2. Study of the Bonham series representation of the Born--Oppenheimer exchange amplitude and the derivation of a local exchange potential

    International Nuclear Information System (INIS)

    Huo, W.M.

    1977-01-01

    The convergence and range of applicability of the Bonham series representation of the Born--Oppenheimer exchange amplitude is investigated. Numerical calculations on 1 1 S→2 3 S and 1 1 S→2 3 P of He by electron impact demonstrate that the first three terms of the Bonham series can provide an adequate representation of the Born--Oppenheimer amplitude from high energies down to near threshold. The three-term Bonham series is then used to represent the Hartree--Fock exchange kernel in momentum space, which has been shown by Lassettre to be proportional to the Born--Oppenheimer amplitude. Inverse Fourier transform, plus an additional approximation of replacing the momentum which appears as an expansion parameter in the Bonham series by its averge value, gives us a local exchange potential. If the averge momentum in the Thomas--Fermi model is used, the first term of the local exchange potential is just the electron gas exchange potential. A second term corresponding to a correction for the inhomogeneity in the electron gas density, is also obtained. No adjustable parameter is involved. Exchange energies of He, Be, and Ne calculated using the local exchange potential agree much better with the Hartree--Fock results than the electron gas model

  3. Born-Oppenheimer potential energy for interaction of antihydrogen with molecular hydrogen

    International Nuclear Information System (INIS)

    Strasburger, Krzysztof

    2005-01-01

    Inelastic collisions with hydrogen molecules are claimed to be an important channel of antihydrogen Hbar losses (Armour and Zeman 1999 Int. J. Quantum Chem. 74 645). In the present work, interaction energies for the H 2 -Hbar 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 H 2 was fixed at equilibrium geometry and the Hbar 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

  4. Born Oppenheimer potential energy for interaction of antihydrogen with molecular hydrogen

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  6. Generalized Born-Oppenheimer treatment of Jahn-Teller systems in Hilbert spaces of arbitrary dimension: theory and application to a three-state model potential.

    Science.gov (United States)

    Varandas, A J C; Sarkar, B

    2011-05-14

    Generalized Born-Oppenheimer equations including the geometrical phase effect are derived for three- and four-fold electronic manifolds in Jahn-Teller systems near the degeneracy seam. The method is readily extendable to N-fold systems of arbitrary dimension. An application is reported for a model threefold system, and the results are compared with Born-Oppenheimer (geometrical phase ignored), extended Born-Oppenheimer, and coupled three-state calculations. The theory shows unprecedented simplicity while depicting all features of more elaborated ones.

  7. Following the non-Born-Oppenheimer electron dynamics after photoionization in the Zundel cation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zheng; Santra, Robin [CFEL, DESY, Notkestr. 85, D-22607 Hamburg (Germany); Department of Physics, University of Hamburg, D-20355 Hamburg (Germany); El-Amine Madjet, Mohamed; Vendrell, Oriol [CFEL, DESY, Notkestr. 85, D-22607 Hamburg (Germany)

    2013-07-01

    To investigate the molecular non-Born-Oppenheimer effects, the Coulomb explosion after valence photoionization provides an excellent test-ground, since it is associated with ultrafast non-adiabatic electronic decay, and is experimentally practical with well-developed techniques. We have employed full quantum (MCTDH) and quantum-classical approaches to study the Coulomb explosion of the Zundel dication H{sub 5}O{sub 2}{sup 2+}. In the present study, we have calculated time-resolved observables that are able to provide a clear picture of the specific electronic and nuclear motions arising exclusively from the non-Born-Oppenheimer effects. The Coulomb explosion experiments of molecular ions are suitable to be carried out with the XUV free electron laser FLASH, which can address the valence electrons for chemical reactions, meanwhile the high brightness of FEL offers sufficient signal strength, as illustrated experimentally.

  8. The structure of the second-order non-Born-Oppenheimer density matriz D2:

    Science.gov (United States)

    Ludena, Eduardo; Iza, Peter; Aray, Yosslen; Cornejo, Mauricio; Zambrano, Dik

    Properties of the non-Born-Oppenheimer 2-matrix are examined. Using a coordinate system formed by internal translationally invariant plus the total center-of-mass coordinates it is shown that regardless of the point of reference selected, the operator for the reduced second order density matrix, 2-RDM, solely depends upon the translationally invariant internal coordinates. We apply this result to examine the nature of the 2-RDM extracted from the exact analytical solutions for model non-Born-Oppenheimer four-particle systems of the Coulomb-Hooke and Moshinsky types. We obtain for both these models explicit closed-form analytic expressions for the electron and nuclear 2-RDM. An explicit expression is also obtained for the electron-nuclear 2-RDM in the Moshinsky case, which shows coupling between the electron and nuclear coordinates. EVL and YA acknowledge support of SENESCYT's Prometheus Program.

  9. Beyond-Born-Oppenheimer effects in sub-kHz-precision photoassociation spectroscopy of ytterbium atoms

    Science.gov (United States)

    Borkowski, Mateusz; Buchachenko, Alexei A.; Ciuryło, Roman; Julienne, Paul S.; Yamada, Hirotaka; Kikuchi, Yuu; Takahashi, Kakeru; Takasu, Yosuke; Takahashi, Yoshiro

    2017-12-01

    We present high-resolution two-color photoassociation spectroscopy of Bose-Einstein condensates of ytterbium atoms. The use of narrow Raman resonances and careful examination of systematic shifts enabled us to measure 13 bound-state energies for three isotopologues of the ground-state ytterbium molecule with standard uncertainties of the order of 500 Hz. The atomic interactions are modeled using an ab initio based mass-scaled Born-Oppenheimer potential whose long-range van der Waals parameters and total WKB phase are fitted to experimental data. We find that the quality of the fit of this model, of about 112.9 kHz (rms) can be significantly improved by adding the recently calculated beyond-Born-Oppenheimer (BBO) adiabatic corrections [J. J. Lutz and J. M. Hutson, J. Mol. Spectrosc. 330, 43 (2016), 10.1016/j.jms.2016.08.007] and by partially treating the nonadiabatic effects using distance-dependent reduced masses. Our BBO interaction model represents the experimental data to within about 30.2 kHz on average, which is 3.7 times better than the "reference" Born-Oppenheimer model. We calculate the s -wave scattering lengths for bosonic isotopic pairs of ytterbium atoms with error bars over two orders of magnitude smaller than previous determinations. For example, the s -wave scattering length for 174Yb is +5.55812 (50 ) nm.

  10. Functional Representation for the Born-Oppenheimer Diagonal Correction and Born-Huang Adiabatic Potential Energy Surfaces for Isotopomers of H3

    International Nuclear Information System (INIS)

    Mielke, Steven L.; Schwenke, David; Schatz, George C.; Garrett, Bruce C.; Peterson, Kirk A.

    2009-01-01

    Multireference configuration interaction (MRCI) calculations of the Born-Oppenheimer diagonal correction (BODC) for H3 were performed at 1397 symmetry-unique configurations using the Born-Huang approach; isotopic substitution leads to 4041 symmetry-unique configurations for the DH2 mass combination. These results were then fit to a functional form that permits calculation of the BODC for any combination of isotopes. Mean unsigned fitting errors on a test grid of configurations not included in the fitting process were 0.14, 0.12, and 0.65 cm-1 for the H3, DH2, and MuH2 isotopomers, respectively. This representation can be combined with any Born-Oppenheimer potential energy surface (PES) to yield Born-Huang (BH) PESs; herein we choose the CCI potential energy surface, the uncertainties of which (∼0.01 kcal/mol) are much smaller than the magnitude of the BODC. FORTRAN routines to evaluate these BH surfaces are provided. Variational transition state theory calculations are presented comparing thermal rate constants for reactions on the BO and BH surfaces to provide an initial estimate of the significance of the diagonal correction for the dynamics.

  11. Wave function continuity and the diagonal Born-Oppenheimer correction at conical intersections.

    Science.gov (United States)

    Meek, Garrett A; Levine, Benjamin G

    2016-05-14

    We demonstrate that though exact in principle, the expansion of the total molecular wave function as a sum over adiabatic Born-Oppenheimer (BO) vibronic states makes inclusion of the second-derivative nonadiabatic energy term near conical intersections practically problematic. In order to construct a well-behaved molecular wave function that has density at a conical intersection, the individual BO vibronic states in the summation must be discontinuous. When the second-derivative nonadiabatic terms are added to the Hamiltonian, singularities in the diagonal BO corrections (DBOCs) of the individual BO states arise from these discontinuities. In contrast to the well-known singularities in the first-derivative couplings at conical intersections, these singularities are non-integrable, resulting in undefined DBOC matrix elements. Though these singularities suggest that the exact molecular wave function may not have density at the conical intersection point, there is no physical basis for this constraint. Instead, the singularities are artifacts of the chosen basis of discontinuous functions. We also demonstrate that continuity of the total molecular wave function does not require continuity of the individual adiabatic nuclear wave functions. We classify nonadiabatic molecular dynamics methods according to the constraints placed on wave function continuity and analyze their formal properties. Based on our analysis, it is recommended that the DBOC be neglected when employing mixed quantum-classical methods and certain approximate quantum dynamical methods in the adiabatic representation.

  12. Chaos induced by quantum effect due to breakdown of the Born-Oppenheimer adiabaticity

    International Nuclear Information System (INIS)

    Fujisaki, Hiroshi; Takatsuka, Kazuo

    2001-01-01

    Chaos in the multimode nonadiabatic system constructed by Heller [J. Chem. Phys. >92, 1718 (1990)], which consists of two diabatic two-dimensional harmonic potentials with the Condon coupling, is studied. A thorough investigation is carried out by scanning the magnitudes of the Condon coupling and the Duschinsky angle. To elucidate mechanisms that can cause chaos in this quantum system, the statistical properties of the energy levels and eigenfunctions of the system are investigated. We find an evidence in terms of the nearest-neighbor spacing distribution of energy levels and other measures that a certain class of chaos is purely induced by the nonadiabatic interaction due to breakdown of the Born-Oppenheimer approximation. Since the nonadiabatic transition can induce repeated bifurcation and merging of a wave packet around the region of quasicrossing between two potential surfaces, and since this interaction does not have a counterpart in the lower adiabatic system, the present chaos deserves being called 'nonadiabatic chaos.' Another type of chaos in a nonadiabatic system was previously identified [D. M. Leitner et al., J. Chem. Phys. >104, 434 (1996)] that reflects the inherent chaos of a corresponding adiabatic potential. We present a comparative study to establish the similarity and difference between these kinds of chaos

  13. Canonical-ensemble extended Lagrangian Born-Oppenheimer molecular dynamics for the linear scaling density functional theory.

    Science.gov (United States)

    Hirakawa, Teruo; Suzuki, Teppei; Bowler, David R; Miyazaki, Tsuyoshi

    2017-10-11

    We discuss the development and implementation of a constant temperature (NVT) molecular dynamics scheme that combines the Nosé-Hoover chain thermostat with the extended Lagrangian Born-Oppenheimer molecular dynamics (BOMD) scheme, using a linear scaling density functional theory (DFT) approach. An integration scheme for this canonical-ensemble extended Lagrangian BOMD is developed and discussed in the context of the Liouville operator formulation. Linear scaling DFT canonical-ensemble extended Lagrangian BOMD simulations are tested on bulk silicon and silicon carbide systems to evaluate our integration scheme. The results show that the conserved quantity remains stable with no systematic drift even in the presence of the thermostat.

  14. Extended Lagrangian Born-Oppenheimer molecular dynamics simulations of the shock-induced chemistry of phenylacetylene

    Energy Technology Data Exchange (ETDEWEB)

    Cawkwell, M. J., E-mail: cawkwell@lanl.gov; Niklasson, Anders M. N. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Dattelbaum, Dana M. [Weapons Experiments Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2015-02-14

    The initial chemical events that occur during the shock compression of liquid phenylacetylene have been investigated using self-consistent tight binding molecular dynamics simulations. The extended Lagrangian Born-Oppenheimer molecular dynamics formalism enabled us to compute microcanonical trajectories with precise conservation of the total energy. Our simulations revealed that the first density-increasing step under shock compression arises from the polymerization of phenylacetylene molecules at the acetylene moiety. The application of electronic structure-based molecular dynamics with long-term conservation of the total energy enabled us to identify electronic signatures of reactivity via monitoring changes in the HOMO-LUMO gap, and to capture directly adiabatic shock heating, transient non-equilibrium states, and changes in temperature arising from exothermic chemistry in classical molecular dynamics trajectories.

  15. Extended Lagrangian Born-Oppenheimer molecular dynamics simulations of the shock-induced chemistry of phenylacetylene.

    Science.gov (United States)

    Cawkwell, M J; Niklasson, Anders M N; Dattelbaum, Dana M

    2015-02-14

    The initial chemical events that occur during the shock compression of liquid phenylacetylene have been investigated using self-consistent tight binding molecular dynamics simulations. The extended Lagrangian Born-Oppenheimer molecular dynamics formalism enabled us to compute microcanonical trajectories with precise conservation of the total energy. Our simulations revealed that the first density-increasing step under shock compression arises from the polymerization of phenylacetylene molecules at the acetylene moiety. The application of electronic structure-based molecular dynamics with long-term conservation of the total energy enabled us to identify electronic signatures of reactivity via monitoring changes in the HOMO-LUMO gap, and to capture directly adiabatic shock heating, transient non-equilibrium states, and changes in temperature arising from exothermic chemistry in classical molecular dynamics trajectories.

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

    Science.gov (United States)

    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.

  17. Mass distribution of fission fragments within the Born-Oppenheimer approximation

    Energy Technology Data Exchange (ETDEWEB)

    Pomorski, K.; Nerlo-Pomorska, B. [M.C.S. University, Department of Theoretical Physics, Lublin (Poland); Ivanyuk, F.A. [Institute for Nuclear Research, Kiev (Ukraine)

    2017-03-15

    The fission fragments mass-yield of {sup 236} U is obtained by an approximate solution of the eigenvalue problem of the collective Hamiltonian that describes the dynamics of the fission process whose degrees of freedom are: the fission (elongation), the neck and mass-asymmetry modes. The macroscopic-microscopic method is used to evaluate the potential energy surface. The macroscopic energy part is calculated using the liquid drop model and the microscopic corrections are obtained using a Woods-Saxon single-particle levels. The four-dimensional modified Cassini ovals shape parametrization is used to describe the shape of the fissioning nucleus. The mass tensor is taken within a cranking-type approximation. The final fragment mass distribution is obtained by weighting the adiabatic density distribution in the collective space with the neck-dependent fission probability. The neck degree of freedom is found to play a significant role in determining the final fragment mass distribution. (orig.)

  18. Virial theorem and the Born-Oppenheimer approximation at different orders of perturbation

    International Nuclear Information System (INIS)

    Olivier, Gabriel; Weislinger, Edmond

    1977-01-01

    The link between the virial theorem and the adiabatic approximation is studied for a few orders of perturbation. It is shown that the total energy of the system is distributed between the mean values of kinetic and potential energy of the nuclei and the electrons in each order of perturbation. No static approximation connected with the Hellmann-Feynman theorem is made [fr

  19. Non-Born-Oppenheimer electronic and nuclear densities for a Hooke-Calogero three-particle model: non-uniqueness of density-derived molecular structure.

    Science.gov (United States)

    Ludeña, E V; Echevarría, L; Lopez, X; Ugalde, J M

    2012-02-28

    We consider the calculation of non-Born-Oppenheimer, nBO, one-particle densities for both electrons and nuclei. We show that the nBO one-particle densities evaluated in terms of translationally invariant coordinates are independent of the wavefunction describing the motion of center of mass of the whole system. We show that they depend, however, on an arbitrary reference point from which the positions of the vectors labeling the particles are determined. We examine the effect that this arbitrary choice has on the topology of the one-particle density by selecting the Hooke-Calogero model of a three-body system for which expressions for the one-particle densities can be readily obtained in analytic form. We extend this analysis to the one-particle densities obtained from full Coulomb interaction wavefunctions for three-body systems. We conclude, in view of the fact that there is a close link between the choice of the reference point and the topology of one-particle densities that the molecular structure inferred from the topology of these densities is not unique. We analyze the behavior of one-particle densities for the Hooke-Calogero Born-Oppenheimer, BO, wavefunction and show that topological transitions are also present in this case for a particular mass value of the light particles even though in the BO regime the nuclear masses are infinite. In this vein, we argue that the change in topology caused by variation of the mass ratio between light and heavy particles does not constitute a true indication in the nBO regime of the emergence of molecular structure.

  20. On transparent potentials: a Born approximation study

    International Nuclear Information System (INIS)

    Coudray, C.

    1980-01-01

    In the frame of the scattering inverse problem at fixed energy, a class of potentials transparent in Born approximation is obtained. All these potentials are spherically symmetric and are oscillating functions of the reduced radial variable. Amongst them, the Born approximation of the transparent potential of the Newton-Sabatier method is found. In the same class, quasi-transparent potentials are exhibited. Very general features of potentials transparent in Born approximation are then stated. And bounds are given for the exact scattering amplitudes corresponding to most of the potentials previously exhibited. These bounds, obtained at fixed energy, and for large values of the angular momentum, are found to be independent on the energy

  1. S-wave Qanti Qqanti q states in the adiabatic approximation

    Energy Technology Data Exchange (ETDEWEB)

    Chao, K T [Oxford Univ. (UK). Dept. of Theoretical Physics

    1981-06-01

    The static potential energy for an S-wave Qanti Qqanti q system is discussed in an adiabatic (Born-Oppenheimer) approximation. Both spherical bag and arbitrary bag are considered. We concentrate on those Qanti Qqanti q states in which both (Qanti Q) and (qanti q) are colour singlets. Their energy level, wave function, and possible experimental observation are studied.

  2. On Born approximation in black hole scattering

    Science.gov (United States)

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

    2011-12-01

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

  3. Oppenheimer the tragic intellect

    CERN Document Server

    Thorpe, Charles

    2008-01-01

    At a time when the Manhattan Project was synonymous with large-scale science, physicist J. Robert Oppenheimer (1904-67) represented the new sociocultural power of the American intellectual. Catapulted to fame as director of the Los Alamos atomic weapons laboratory, Oppenheimer occupied a key position in the compact between science and the state that developed out of World War II. By tracing the making-and unmaking-of Oppenheimer's wartime and postwar scientific identity, Charles Thorpe illustrates the struggles over the role of the scientist in relation to nuclear weapons, the state, and culture.  A stylish intellectual biography, Oppenheimer maps out changes in the roles of scientists and intellectuals in twentieth-century America, ultimately revealing transformations in Oppenheimer's persona that coincided with changing attitudes toward science in society.  "This is an outstandingly well-researched book, a pleasure to read and distinguished by the high quality of its observations and judgments. It will b...

  4. Comparison of the Born series and rational approximants in potential scattering. [Pade approximants, Yikawa and exponential potential

    Energy Technology Data Exchange (ETDEWEB)

    Garibotti, C R; Grinstein, F F [Rosario Univ. Nacional (Argentina). Facultad de Ciencias Exactas e Ingenieria

    1976-05-08

    It is discussed the real utility of Born series for the calculation of atomic collision processes in the Born approximation. It is suggested to make use of Pade approximants and it is shown that this approach provides very fast convergent sequences over all the energy range studied. Yukawa and exponential potential are explicitly considered and the results are compared with high-order Born approximation.

  5. The strange trial of Robert Oppenheimer; L'etrange proces de Robert Oppenheimer

    Energy Technology Data Exchange (ETDEWEB)

    Kevles, D.J. [Yale Univ., New Haven, CT (United States); Institut de Technologie de Californie (United States)

    2004-04-01

    Robert Oppenheimer has become the symbol of the scientist tormented and anguished by the consequences of his discoveries. R.Oppenheimer took a major part in the Manhattan project for the designing of the first atomic bomb. During this period he considered the thermonuclear bomb as the next step to reach but after Japan's surrender he reconsidered his position and favoured a more moderate atomic policy. R.Oppenheimer began to militate in favour of an international control of nuclear energy and wanted that Usa relinquish to design the hydrogen bomb. In 1953 in full Mac-Carthysm era, he was accused of being a communist and of spying for Ussr and as a consequence he was deprived of his office in AEC (atomic energy committee) but in 1963 president Lyndon Johnson rehabilitated him and R.Oppenheimer was awarded the highest reward of AEC: the Enrico Fermi prize. (A.C.)

  6. On the existence of the optimal order for wavefunction extrapolation in Born-Oppenheimer molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Jun; Wang, Han, E-mail: wang-han@iapcm.ac.cn [Institute of Applied Physics and Computational Mathematics, Beijing (China); CAEP Software Center for High Performance Numerical Simulation, Beijing (China); Gao, Xingyu; Song, Haifeng [Institute of Applied Physics and Computational Mathematics, Beijing (China); CAEP Software Center for High Performance Numerical Simulation, Beijing (China); Laboratory of Computational Physics, Beijing (China)

    2016-06-28

    Wavefunction extrapolation greatly reduces the number of self-consistent field (SCF) iterations and thus the overall computational cost of Born-Oppenheimer molecular dynamics (BOMD) that is based on the Kohn–Sham density functional theory. Going against the intuition that the higher order of extrapolation possesses a better accuracy, we demonstrate, from both theoretical and numerical perspectives, that the extrapolation accuracy firstly increases and then decreases with respect to the order, and an optimal extrapolation order in terms of minimal number of SCF iterations always exists. We also prove that the optimal order tends to be larger when using larger MD time steps or more strict SCF convergence criteria. By example BOMD simulations of a solid copper system, we show that the optimal extrapolation order covers a broad range when varying the MD time step or the SCF convergence criterion. Therefore, we suggest the necessity for BOMD simulation packages to open the user interface and to provide more choices on the extrapolation order. Another factor that may influence the extrapolation accuracy is the alignment scheme that eliminates the discontinuity in the wavefunctions with respect to the atomic or cell variables. We prove the equivalence between the two existing schemes, thus the implementation of either of them does not lead to essential difference in the extrapolation accuracy.

  7. Approximated solutions to Born-Infeld dynamics

    International Nuclear Information System (INIS)

    Ferraro, Rafael; Nigro, Mauro

    2016-01-01

    The Born-Infeld equation in the plane is usefully captured in complex language. The general exact solution can be written as a combination of holomorphic and anti-holomorphic functions. However, this solution only expresses the potential in an implicit way. We rework the formulation to obtain the complex potential in an explicit way, by means of a perturbative procedure. We take care of the secular behavior common to this kind of approach, by resorting to a symmetry the equation has at the considered order of approximation. We apply the method to build approximated solutions to Born-Infeld electrodynamics. We solve for BI electromagnetic waves traveling in opposite directions. We study the propagation at interfaces, with the aim of searching for effects susceptible to experimental detection. In particular, we show that a reflected wave is produced when a wave is incident on a semi-space containing a magnetostatic field.

  8. Approximated solutions to Born-Infeld dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Ferraro, Rafael [Instituto de Astronomía y Física del Espacio (IAFE, CONICET-UBA),Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina); Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires,Ciudad Universitaria, Pabellón I, 1428 Buenos Aires (Argentina); Nigro, Mauro [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires,Ciudad Universitaria, Pabellón I, 1428 Buenos Aires (Argentina)

    2016-02-01

    The Born-Infeld equation in the plane is usefully captured in complex language. The general exact solution can be written as a combination of holomorphic and anti-holomorphic functions. However, this solution only expresses the potential in an implicit way. We rework the formulation to obtain the complex potential in an explicit way, by means of a perturbative procedure. We take care of the secular behavior common to this kind of approach, by resorting to a symmetry the equation has at the considered order of approximation. We apply the method to build approximated solutions to Born-Infeld electrodynamics. We solve for BI electromagnetic waves traveling in opposite directions. We study the propagation at interfaces, with the aim of searching for effects susceptible to experimental detection. In particular, we show that a reflected wave is produced when a wave is incident on a semi-space containing a magnetostatic field.

  9. The Born-Oppenheimer molecular simulations of infrared spectra of crystalline poly-(R)-3-hydroxybutyrate with analysis of weak Csbnd H⋯Odbnd C hydrogen bonds

    Science.gov (United States)

    Brela, Mateusz Z.; Boczar, Marek; Wójcik, Marek J.; Sato, Harumi; Nakajima, Takahito; Ozaki, Yukihiro

    2017-06-01

    In this letter we present results of study of weak Csbnd H⋯Odbnd C hydrogen bonds of crystalline poly-(R)-3-hydroxybutyrate (PHB) by using Born-Oppenheimer molecular dynamics. The polymeric structure and IR spectra of PHB result from the presence of the weak hydrogen bonds. We applied the post-molecular dynamics analysis to consider a Cdbnd O motion as indirectly involved in the hydrogen bonds. Quantization of the nuclear motion of the oxygens was done to perform detailed analysis of the strength and properties of the Cdbnd O bands involved in the weak hydrogen bonds. We have also shown the dynamic character of the weak hydrogen bond interactions.

  10. A surprise in the first Born approximation for electron scattering

    International Nuclear Information System (INIS)

    Treacy, M.M.J.; Van Dyck, D.

    2012-01-01

    A standard textbook derivation for the scattering of electrons by a weak potential under the first Born approximation suggests that the far-field scattered wave should be in phase with the incident wave. However, it is well known that waves scattered from a weak phase object should be phase-shifted by π/2 relative to the incident wave. A disturbing consequence of this missing phase is that, according to the Optical Theorem, the total scattering cross section would be zero in the first Born approximation. We resolve this mystery pedagogically by showing that the first Born approximation fails to conserve electrons even to first order. Modifying the derivation to conserve electrons introduces the correct phase without changing the scattering amplitude. We also show that the far-field expansion for the scattered waves used in many texts is inappropriate for computing an exit wave from a sample, and that the near-field expansion also give the appropriately phase-shifted result. -- Highlights: ► The first Born approximation is usually invoked as the theoretical physical basis for kinematical electron scattering theory. ► Although it predicts the correct scattering amplitude, it predicts the wrong phase; the scattered wave is missing a prefactor of i. ► We show that this arises because the standard textbook version of the first Born approximation does not conserve electrons. ► We show how this can be fixed.

  11. Going Beyond the Point Nucleus Approximation to Satisfy the Hellmann–Feynman Theorem: Born–Oppenheimer H2+ in the Ground State

    International Nuclear Information System (INIS)

    Gutlé, Claudine

    2017-01-01

    Incomplete spaces are investigated for solving the Schrödinger equation under the Born–Oppenheimer approximation. It is shown that the Hellmann–Feynman theorem cannot be used for computing the electronic force exerted on a nucleus, when a variational wavefunction with floating centers is used, if multicenter polynomial components are added in order to describe the polarization effects through the chemical bond. This is because the minimum of the potential energy surface is not a stationary point in the direction of the float parameter. Such a failure can be fixed by considering a molecular model with finite size nuclei, as defined herein. The classical electronic force is computed for that model, as compared with the standard point charge approximation, and it is applied to the H 2 + molecular ion. As a result, the former model is found more accurate by several orders of magnitude. (author)

  12. Semiclassical approximations for gravity and the issue of backreaction

    International Nuclear Information System (INIS)

    Padmanabhan, T.

    1989-01-01

    Semiclassical approximations, which are useful in the study of a quantum system interacting with a classical system, are studied and compared. In particular, we consider the Born-Oppenheimer approximation (BOA) (corresponding to G → O at fixed ℎ), the effective action approach (ℎ → O at fixed G) and their combinations. We show that in the strict BOA limit there is no backreaction on gravity. In the effective action approach one can obtain a semi-classical description of gravity, if certain stringent requirements are satisfied. In most situations of interest these conditions will not be met and the O(ℎ) contribution from gravitons will be comparable to that from quantum fields. (author)

  13. American Prometheus. The Triumph and Tragedy of J. Robert Oppenheimer. Biography; J. Robert Oppenheimer. Die Biographie

    Energy Technology Data Exchange (ETDEWEB)

    Bird, Kai; Sherwin, Martin J.

    2009-07-01

    A definitive portrait of legendary scientist J. Robert Oppenheimer, the ''father'' of the atomic bomb, discusses his seminal role in the twentieth-century scientific world, as well as his lesser-known roles as family man, supposed communist, and head of Princeton's Institute for Advanced Studies. ''American Prometheus'' is a rich evocation of America in mid-century and a compelling portrait of scientist J. Robert Oppenheimer, a man shaped by its major events--the Depression, World War II, and the Cold War. (orig.) [German] J. Robert Oppenheimer (1904-1967), der ''Vater der Atombombe'', zaehlt zu den schillerndsten Figuren der juengeren Zeitgeschichte. Fuer ihre glaenzende Biographie des ''amerikanischen Prometheus'' erhielten der Journalist Kai Bird und der Historiker Martin J. Sherwin den Pulitzer-Preis. Exemplarisch lassen sie das Drama eines Forschers lebendig werden, der sich zwischen Erkenntnisdrang und ethischer Verantwortung entscheiden muss. Oppenheimer leitete das streng geheime Manhattan-Projekt in der Wueste von New Mexico, wo am 16. Juli 1945 die erste Atombombe gezuendet wurde. Kurz darauf starben in Hiroshima und Nagasaki mehr als 200 000 Menschen durch die neue ''Wunderwaffe'' - die Menschheit war ins Atomzeitalter eingetreten. Erschuettert von der Zerstoerungskraft seiner Schoepfung, engagierte sich Oppenheimer fortan gegen den Einsatz nuklearer Waffen. Das machte ihn im Amerika der McCarthy-Aera verdaechtig. Er geriet ins Visier des FBI, wurde als Spion der Sowjetunion verleumdet und musste den Staatsdienst quittieren. Sein Privatleben wurde an die Oeffentlichkeit gezerrt, seine Wohnung verwanzt, sein Telefon abgehoert. Erst 1963 rehabilitierte ihn Praesident Kennedy. Ueber dreissig Jahre hinweg haben die Autoren Interviews mit Oppenheimers Angehoerigen, Freunden und Kollegen gefuehrt, FBI-Akten gesichtet, Tonbaender von Reden und Verhoeren

  14. The strange trial of Robert Oppenheimer

    International Nuclear Information System (INIS)

    Kevles, D.J.

    2004-01-01

    Robert Oppenheimer has become the symbol of the scientist tormented and anguished by the consequences of his discoveries. R.Oppenheimer took a major part in the Manhattan project for the designing of the first atomic bomb. During this period he considered the thermonuclear bomb as the next step to reach but after Japan's surrender he reconsidered his position and favoured a more moderate atomic policy. R.Oppenheimer began to militate in favour of an international control of nuclear energy and wanted that Usa relinquish to design the hydrogen bomb. In 1953 in full Mac-Carthysm era, he was accused of being a communist and of spying for Ussr and as a consequence he was deprived of his office in AEC (atomic energy committee) but in 1963 president Lyndon Johnson rehabilitated him and R.Oppenheimer was awarded the highest reward of AEC: the Enrico Fermi prize. (A.C.)

  15. Validity of the Born approximation for beyond Gaussian weak lensing observables

    Science.gov (United States)

    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.

  16. Hermann Oppenheim's observations about music in aphasia.

    Science.gov (United States)

    Graziano, Amy B; Pech, Anja; Hou, Craig; Johnson, Julene K

    2012-01-01

    Hermann Oppenheim was influential in many areas of neurology, but his ideas about music are relatively unknown. In 1888, he published a paper that outlined how the assessment of music skills in patients with aphasia could lead to a better understanding of aphasia and language. Oppenheim conducted the first comprehensive music assessment as part of a neurologic examination and presented the first case series of music in aphasia. His paper was widely cited and had significant influence over the next 30 years. Although largely unrecognized as such, Oppenheim was an important historical figure in the study of music and neurology.

  17. Mixed-Valence Molecular Unit for Quantum Cellular Automata: Beyond the Born-Oppenheimer Paradigm through the Symmetry-Assisted Vibronic Approach.

    Science.gov (United States)

    Clemente-Juan, Juan Modesto; Palii, Andrew; Coronado, Eugenio; Tsukerblat, Boris

    2016-08-09

    In this article, we focus on the electron-vibrational problem of the tetrameric mixed-valence (MV) complexes proposed for implementation as four-dot molecular quantum cellular automata (mQCA).1 Although the adiabatic approximation explored in ref 2 is an appropriate tool for the qualitative analysis of the basic characteristics of mQCA, like vibronic trapping of the electrons encoding binary information and cell-cell response, it loses its accuracy providing moderate vibronic coupling and fails in the description of the discrete pattern of the vibronic levels. Therefore, a precise solution of the quantum-mechanical vibronic problem is of primary importance for the evaluation of the shapes of the electron transfer optical absorption bands and quantitative analysis of the main parameters of tetrameric quantum cells. Here, we go beyond the Born-Oppenheimer paradigm and present a solution of the quantum-mechanical pseudo Jahn-Teller (JT) vibronic problem in bielectronic MV species (exemplified by the tetra-ruthenium complexes) based on the recently developed symmetry-assisted approach.3,4 The mathematical approach to the vibronic eigenproblem takes into consideration the point symmetry basis, and therefore, the total matrix of the JT Hamiltonian is blocked to the maximum extent. The submatrices correspond to the irreducible representations (irreps) of the point group. With this tool, we also extend the theory of the mQCA cell beyond the limit of prevailing Coulomb repulsion in the electronic pair (adopted in ref 2), and therefore, the general pseudo-JT problems for spin-singlet ((1)B1g, 2(1)A1g, (1)B2g, (1)Eu) ⊗ (b1g + eu) and spin-triplet states ((3)A2g, (3)B1g, 2(3)Eu) ⊗ (b1g + eu) in a square-planar bielectronic system are solved. The obtained symmetry-adapted electron-vibrational functions are employed for the calculation of the profiles (shape functions) of the charge transfer absorption bands in the tetrameric MV complexes and for the discussion of the

  18. Robert Oppenheimer

    International Nuclear Information System (INIS)

    Rival, M.

    1995-01-01

    Graduate from Harvard, reputed professor, founder of the first theoretical physics high school of the Usa, Robert Oppenheimer is nominated in 1942 scientific director of the ''Y project'', the research program for the nuclear weapon fabrication. This book describes its life and the evolution of the Los Alamos researches up to the first test, its opposition to the thermo-nuclear weapon, and the maccarthysm period. (A.B.)

  19. Applicability of refined Born approximation to non-linear equations

    International Nuclear Information System (INIS)

    Rayski, J.

    1990-01-01

    A computational method called ''Refined Born Approximation'', formerly applied exclusively to linear problems, is shown to be successfully applicable also to non-linear problems enabling me to compute bifurcations and other irregular solutions which cannot be obtained by the standard perturbation procedures. (author)

  20. The boundary-corrected second Born (B2B) approximation: proton-hydrogen electron capture

    International Nuclear Information System (INIS)

    Dewangan, D.P.; Bransden, B.H.

    1988-01-01

    The probability amplitude for proton-hydrogen ground-state electron capture at 125 keV in the boundary-corrected second Born approximation has been evaluated numerically by retaining all significant bound and continuum hydrogenic intermediate states for which the orbital angular momentum l ≤ 3. The differential cross section is found to be in good agreement with the experimental data for scattering angles less than about 1 mrad in the centre of mass system. The value of the boundary-corrected second Born total cross section is similar to that obtained in the boundary-corrected first Born approximation. (author)

  1. The meanings of J. Robert Oppenheimer

    CERN Document Server

    Banco, Lindsey Michael

    2016-01-01

    He called the first atomic bomb “technically sweet,” yet as he watched its brilliant light explode over the New Mexico desert in 1945 in advance of the black horrors of Hiroshima and Nagasaki, he also thought of the line from the Hindu epic The Bhagavad Gita: “I am become Death, the destroyer of worlds.” Physicist J. Robert Oppenheimer, the scientific director of the Manhattan Project, the single most recognizable face of the atomic bomb, and a man whose name has become almost synonymous with Cold War American nuclear science, was and still is a conflicted, controversial figure who has come to represent an equally ambivalent technology. The Meanings of J. Robert Oppenheimer examines how he has been represented over the past seven decades in biographies, histories, fiction, comics, photographs, film, television, documentaries, theater, and museums. Lindsey Michael Banco gathers an unprecedented group of cultural texts and seeks to understand the multiple meanings Oppenheimer has held in American popul...

  2. A comparative study of the second-order Born and Faddeev-Watson approximations: Pt. 3

    International Nuclear Information System (INIS)

    Roberts, M.J.

    1988-01-01

    Singularities which arise in the second-order Born and Faddeev-Watson approximations for ionisation processes are examined. A regularisation procedure for the latter is suggested. Comparison with He(e,2e)He + experimental data in symmetric coplanar energy-sharing kinematics shows that the second-order Faddeev-Watson approximation is inferior to the second Born results of Byron et al. (1985. J. Phys. B: At. Mol. Phys. 18, 3203). (author)

  3. Inverse bremsstrahlung heating beyond the first Born approximation for dense plasmas in laser fields

    International Nuclear Information System (INIS)

    Moll, M; Schlanges, M; Bornath, Th; Krainov, V P

    2012-01-01

    Inverse bremsstrahlung (IB) heating, an important process in the laser-matter interaction, involves two different kinds of interaction—the interaction of the electrons with the external laser field and the electron-ion interaction. This makes analytical approaches very difficult. In a quantum perturbative approach to the IB heating rate in strong laser fields, usually the first Born approximation with respect to the electron-ion potential is considered, whereas the influence of the electric field is taken exactly in the Volkov wave functions. In this paper, a perturbative treatment is presented adopting a screened electron-ion interaction potential. As a new result, we derive the momentum-dependent, angle-averaged heating rate in the first Born approximation. Numerical results are discussed for a broad range of field strengths, and the conditions for the applicability of a linear approximation for the heating rate are analyzed in detail. Going a step further in the perturbation series, we consider the transition amplitude in the second Born approximation, which enables us to calculate the heating rate up to the third order of the interaction strength. (paper)

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

    Science.gov (United States)

    Kilcrease, D. P.; Brookes, S.

    2013-12-01

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

  5. A comparative study of the second-order Born and Faddeev-Watson approximations for electron-atom collisions

    International Nuclear Information System (INIS)

    Fargher, H.E.; Roberts, M.J.

    1983-01-01

    Simplified versions of the second-order Born and Faddeev-Watson approximations are applied to the excitation of the n=2 levels of atomic hydrogen by the impact of 54.4 eV electrons. The theories are compared with the measurements of differential cross sections and angular correlation parameters. The results indicate that the Born approximation is better at low angles of scattering but that the Faddeev-Watson approximation is better at high angles. The importance of the phases of the two-body T matrices in the Faddeev-Watson approximation is illustrated. (author)

  6. Off-shell properties of the second-order Born approximation for laser-assisted potential scattering

    International Nuclear Information System (INIS)

    Trombetta, F.

    1991-01-01

    A formal method is presented to evaluate the second-order Born approximation of the laser-assisted potential scattering. It is an implicit closure technique that includes intermediate virtual-state transitions and enables one to find the exact explicit expression of the transition amplitude. This is of interest from two standpoints: first, one can deal with ranges of parameters in which the first-order Born approximation is a poor one; second, one can set limits of on-shell approximations that are also widely used to analyze recent laser-assisted experiments. The off-shell character yields new terms in the exact amplitude, and in particular, it is shown to play a crucial role in forward scattering from a long-range potential

  7. Aqueous solvation of Mg(ii) and Ca(ii): A Born-Oppenheimer molecular dynamics study of microhydrated gas phase clusters

    Science.gov (United States)

    León-Pimentel, C. I.; Amaro-Estrada, J. I.; Hernández-Cobos, J.; Saint-Martin, H.; Ramírez-Solís, A.

    2018-04-01

    The hydration features of [Mg(H2O)n ] 2 + and [Ca(H2O)n ] 2 + clusters with n = 3-6, 8, 18, and 27 were studied by means of Born-Oppenheimer molecular dynamics simulations at the B3LYP/6-31+G** level of theory. For both ions, it is energetically more favorable to have all water molecules in the first hydration shell when n ≤ 6, but stable lower coordination average structures with one water molecule not directly interacting with the ion were found for Mg2+ at room temperature, showing signatures of proton transfer events for the smaller cation but not for the larger one. A more rigid octahedral-type structure for Mg2+ than for Ca2+ was observed in all simulations, with no exchange of water molecules to the second hydration shell. Significant thermal effects on the average structure of clusters were found: while static optimizations lead to compact, spherically symmetric hydration geometries, the effects introduced by finite-temperature dynamics yield more prolate configurations. The calculated vibrational spectra are in agreement with infrared spectroscopy results. Previous studies proposed an increase in the coordination number (CN) from six to eight water molecules for [Ca(H2O)n ] 2 + clusters when n ≥ 12; however, in agreement with recent measurements of binding energies, no transition to a larger CN was found when n > 8. Moreover, the excellent agreement found between the calculated extended X-ray absorption fine structure spectroscopy spectra for the larger cluster and the experimental data of the aqueous solution supports a CN of six for Ca2+.

  8. Periodic orbits of the hydrogen molecular ion and their quantization

    International Nuclear Information System (INIS)

    Duan, Y.; Yuan, J.; Bao, C.

    1995-01-01

    In a classical study of the hydrogen molecular ion beyond the Born-Oppenheimer approximation (BOA), we have found that segments of trajectories resemble that of the Born-Oppenheimer approximation periodic orbits. The importance of this fact to the classical understanding of chemical bonding leads us to a systematic study of the periodic orbits of the planar hydrogen molecular ion within the BOA. Besides introducing a classification scheme for periodic orbits, we discuss the convergence properties of families of periodic orbits and their bifurcation patterns according to their types. Semiclassical calculations of the density of states based on these periodic orbits yield results in agreement with the exact quantum eigenvalues of the hydrogen molecular ion system

  9. Repulsive Gravity in the Oppenheimer-Snyder Collapsar

    Directory of Open Access Journals (Sweden)

    Marshall T. W.

    2016-07-01

    Full Text Available The Oppenheimer-Snyder metric for a collapsing dust ball has a well defined equilib- rium state when the time coordinate goes to plus infinity. The entire ball is contained within the gravitational radius r 0 , but half of its content lies within a thin shell between r 0 and 0 : 94 r 0 . This state has the acausal property that no light ray escapes from it, but if one boundary condition at the surface, which Oppenheimer and Snyder imposed without justification, is removed, then all points in the interior remain in causal contact by null geodesics with the exterior. This modification causes the half shell’s interior radius to increase to 0 : 97 r 0 . Together with the results of a previous article on the den- sity inside a spherosymmetric neutron star, the present results indicate that, in contrast with the universal attraction of Newtonian gravity, General Relativity gives gravitational repulsion at high density.

  10. American Prometheus. The Triumph and Tragedy of J. Robert Oppenheimer. Biography

    International Nuclear Information System (INIS)

    Bird, Kai; Sherwin, Martin J.

    2009-01-01

    A definitive portrait of legendary scientist J. Robert Oppenheimer, the ''father'' of the atomic bomb, discusses his seminal role in the twentieth-century scientific world, as well as his lesser-known roles as family man, supposed communist, and head of Princeton's Institute for Advanced Studies. ''American Prometheus'' is a rich evocation of America in mid-century and a compelling portrait of scientist J. Robert Oppenheimer, a man shaped by its major events--the Depression, World War II, and the Cold War. (orig.) [de

  11. A finite range coupled channel Born approximation code

    International Nuclear Information System (INIS)

    Nagel, P.; Koshel, R.D.

    1978-01-01

    The computer code OUKID calculates differential cross sections for direct transfer nuclear reactions in which multistep processes, arising from strongly coupled inelastic states in both the target and residual nuclei, are possible. The code is designed for heavy ion reactions where full finite range and recoil effects are important. Distorted wave functions for the elastic and inelastic scattering are calculated by solving sets of coupled differential equations using a Matrix Numerov integration procedure. These wave functions are then expanded into bases of spherical Bessel functions by the plane-wave expansion method. This approach allows the six-dimensional integrals for the transition amplitude to be reduced to products of two one-dimensional integrals. Thus, the inelastic scattering is treated in a coupled channel formalism while the transfer process is treated in a finite range born approximation formalism. (Auth.)

  12. Low Temperature Hydrogen Antihydrogen Interactions

    International Nuclear Information System (INIS)

    Armour, E. A. G.; Chamberlain, C. W.

    2001-01-01

    In view of current interest in the trapping of antihydrogen (H-bar) atoms at low temperatures, we have carried out a full four-body variational calculation to determine s-wave elastic phase shifts for hydrogen antihydrogen scattering, using the Kohn Variational Principle. Terms outside the Born-Oppenheimer approximation have been taken into account using the formalism of Kolos and Wolniewicz. As far as we are aware, this is the first time that these terms have been included in an H H-bar scattering calculation. This is a continuation of earlier work on H-H-bar interactions. Preliminary results differ substantially from those calculated using the Born-Oppenheimer approximation. A method is outlined for reducing this discrepancy and taking the rearrangement channel into account.

  13. Electron impact excitation of positive ions calculated in the Coulomb-Born approximation

    International Nuclear Information System (INIS)

    Nakazaki, Shinobu; Hashino, Tasuke

    1979-08-01

    Theoretical results on the electron impact excitation of positive ions are surveyed through the end of 1978. As a guide to the available data, a list of references is made. The list shows ion species, transitions, energy range and methods of calculation for the respective data. Based on the literature survey, the validity of the Coulomb-Born approximation is investigated. Comparisons with the results of the close-coupling and the distorted-wave methods are briefly summarized. (author)

  14. No surprise in the first Born approximation for electron scattering

    International Nuclear Information System (INIS)

    Lentzen, M.

    2014-01-01

    In a recent article it is argued that the far-field expansion of electron scattering, a pillar of electron diffraction theory, is wrong (Treacy and Van Dyck, 2012 [1]). It is further argued that in the first Born approximation of electron scattering the intensity of the electron wave is not conserved to first order in the scattering potential. Thus a “mystery of the missing phase” is investigated, and the supposed flaw in scattering theory is seeked to be resolved by postulating a standing spherical electron wave (Treacy and Van Dyck, 2012 [1]). In this work we show, however, that these theses are wrong. A review of the essential parts of scattering theory with careful checks of the underlying assumptions and limitations for high-energy electron scattering yields: (1) the traditional form of the far-field expansion, comprising a propagating spherical wave, is correct; (2) there is no room for a missing phase; (3) in the first Born approximation the intensity of the scattered wave is conserved to first order in the scattering potential. The various features of high-energy electron scattering are illustrated by wave-mechanical calculations for an explicit target model, a Gaussian phase object, and for a Si atom, considering the geometric conditions in high-resolution transmission electron microscopy. - Highlights: Treacy and Van Dyck (2012) argue that the far-field expansion of electron scattering is wrong. The chief theses of that former work are wrong. There is no room for the missing phase proposed by Treacy and Van Dyck. There is no violation of the intensity conservation to first order in the scattering potential. Calculations for a phase object and an atomic target confirm traditional scattering theory

  15. Nonlinear optics principles and applications

    CERN Document Server

    Rottwitt, Karsten

    2014-01-01

    IntroductionReview of linear opticsInduced polarizationHarmonic oscillator modelLocal field correctionsEstimated nonlinear responseSummaryTime-domain material responseThe polarization time-response functionThe Born-Oppenheimer approximationRaman scattering response function of silicaSummaryMaterial response in the frequency domain, susceptibility tensorsThe susceptibility tensorThe induced polarization in the frequency domainSum of monochromatic fieldsThe prefactor to the induced polarizationThird-order polarization in the Born-Oppenheimer approximation in the frequency domainKramers-Kronig relationsSummarySymmetries in nonlinear opticsSpatial symmetriesSecond-order materialsThird-order nonlinear materialsCyclic coordinate-systemContracted notation for second-order susceptibility tensorsSummaryThe nonlinear wave equationMono and quasi-monochromatic beamsPlane waves - the transverse problemWaveguidesVectorial approachNonlinear birefringenceSummarySecond-order nonlinear effectsGeneral theoryCoupled wave theoryP...

  16. Simultaneous analysis of rotational and vibrational-rotational spectra of DF and HF to obtain irreducible molecular constants for HF

    International Nuclear Information System (INIS)

    Horiai, Koui; Uehara, Hiromichi

    2011-01-01

    Graphical abstract: Available rotational and vibrational-rotational spectral lines of DF and HF are analyzed simultaneously using a non-Born-Oppenheimer effective Hamiltonian. Research highlights: → Simultaneous analysis of DF and HF spectral data. → Application of a non-Born-Oppenheimer effective Hamiltonian. → Twenty irreducible molecular constants for HF have been determined. - Abstract: Analytic expressions of corrections for the breakdown of the Born-Oppenheimer approximation to Dunham's Y ij with optimal parameters, i.e., determinable clusters of expansion coefficients, are applied to a data analysis of the rotational and vibrational-rotational transitions of HF reported in the literature. All the available spectral lines of the two isotopologues, DF and HF, are simultaneously fitted to a single set of molecular parameters of HF within experimental errors. Fitting of a data set of 595 spectral transitions for DF and HF has generated only 20 minimal independent parameter values, i.e., 'irreducible' molecular constants of HF, that are sufficient to precisely generate 82 Y ij coefficients and 144 band constants in total: 41 Y ij and 72 band constants each for DF and HF.

  17. Next generation extended Lagrangian first principles molecular dynamics.

    Science.gov (United States)

    Niklasson, Anders M N

    2017-08-07

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

  18. The Early Scientific Contributions of J. Robert Oppenheimer: Why Did the Scientific Community Miss the Black Hole Opportunity?

    Science.gov (United States)

    Ortega-Rodríguez, M.; Solís-Sánchez, H.; Boza-Oviedo, E.; Chaves-Cruz, K.; Guevara-Bertsch, M.; Quirós-Rojas, M.; Vargas-Hernández, S.; Venegas-Li, A.

    2017-04-01

    We assess the scientific value of Oppenheimer's research on black holes in order to explain its neglect by the scientific community, and even by Oppenheimer himself. Looking closely at the scientific culture and conceptual belief system of the 1930s, the present article seeks to supplement the existing literature by enriching the explanations and complicating the guiding questions. We suggest a rereading of Oppenheimer as a figure both more intriguing for the history of astrophysics and further ahead of his time than is commonly supposed.

  19. Efimov States of Heavy Impurities in a Bose-Einstein Condensate

    DEFF Research Database (Denmark)

    Zinner, Nikolaj Thomas

    2013-01-01

    We consider the problem of two heavy impurity particles embedded in a gas of weakly-interacting light mass bosonic particles in the condensed state. Using the Bogoliubov approach to describe the bosonic gas and the Born-Oppenheimer approximation for the three-body dynamics, we calculate the modif......We consider the problem of two heavy impurity particles embedded in a gas of weakly-interacting light mass bosonic particles in the condensed state. Using the Bogoliubov approach to describe the bosonic gas and the Born-Oppenheimer approximation for the three-body dynamics, we calculate...... the modification to the heavy-heavy two-body potential due to the presence of the condensate. For the case of resonant interaction between the light bosons and the impurities, we present (semi)-analytical results for the potential in the limit of a large condensate coherence length. In particular, we find...

  20. Beyond the Born approximation. The case of very long polymer chains adsorbed at an interface

    International Nuclear Information System (INIS)

    Guiselin, O.; Jannink, G.; Cloizeaux, J. des

    1991-01-01

    Two experimental evidences are discussed of the reflectance discontinuity associated with very long adsorbed polymer chains. It is shown that the Born approximation is not valid in this case. The anomalous low reflectivity is compared to the Ramsauer-Townsend effect in the scattering of slow electrons by rare-gas atoms. (author) 15 refs.; 6 figs

  1. Low-energy Scattering of Positronium by Atoms

    Science.gov (United States)

    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.

  2. Born approximation to a perturbative numerical method for the solution of the Schrodinger equation

    International Nuclear Information System (INIS)

    Adam, Gh.

    1978-05-01

    A perturbative numerical (PN) method is given for the solution of a regular one-dimensional Cauchy problem arising from the Schroedinger equation. The present method uses a step function approximation for the potential. Global, free of scaling difficulty, forward and backward PN algorithms are derived within first order perturbation theory (Born approximation). A rigorous analysis of the local truncation errors is performed. This shows that the order of accuracy of the method is equal to four. In between the mesh points, the global formula for the wavefunction is accurate within O(h 4 ), while that for the first order derivative is accurate within O(h 3 ). (author)

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

    Science.gov (United States)

    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.

  4. Scattering of plane waves by rough surfaces in the sense of Born approximation

    OpenAIRE

    Arnold, Thomas

    2014-01-01

    Das Thema dieser Arbeit ist die Streuung elektromagnetischer ebener Wellen an rauen Oberflächen, also an ebenen Oberflächen mit glatten und beschränkten Störungen. Darüber hinaus wird ein kleiner Kontrast der Materialkonstanten zwischen dem Deckmaterial und dem Material unter der rauen Oberfläche angenommen. Unter diesen Voraussetzungen wird ein Fernfeld-Formel für das gestreute Feld mit Hilfe von Born-Approximation und Fourier-Techniken hergeleitet. Dieser Ansatz basiert auf einer Modifikati...

  5. Dunham spectroscopic constants for the ground and excited states of H2+

    International Nuclear Information System (INIS)

    Murai, Tomokazu

    1975-01-01

    The Dunham spectroscopic constants for 12 of the electronic states of H 2 + are computed theoretically from the adiabatic potentials, which are calculated by the author based on the method presented by Bates et al. in the Born-Oppenheimer approximation. (author)

  6. Energy transfer in structured and unstructured environments: Master equations beyond the Born-Markov approximations

    Energy Technology Data Exchange (ETDEWEB)

    Iles-Smith, Jake, E-mail: Jakeilessmith@gmail.com [Controlled Quantum Dynamics Theory, Imperial College London, London SW7 2PG (United Kingdom); Photon Science Institute and School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Department of Photonics Engineering, DTU Fotonik, Ørsteds Plads, 2800 Kongens Lyngby (Denmark); Dijkstra, Arend G. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Lambert, Neill [CEMS, RIKEN, Saitama 351-0198 (Japan); Nazir, Ahsan, E-mail: ahsan.nazir@manchester.ac.uk [Photon Science Institute and School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom)

    2016-01-28

    We explore excitonic energy transfer dynamics in a molecular dimer system coupled to both structured and unstructured oscillator environments. By extending the reaction coordinate master equation technique developed by Iles-Smith et al. [Phys. Rev. A 90, 032114 (2014)], we go beyond the commonly used Born-Markov approximations to incorporate system-environment correlations and the resultant non-Markovian dynamical effects. We obtain energy transfer dynamics for both underdamped and overdamped oscillator environments that are in perfect agreement with the numerical hierarchical equations of motion over a wide range of parameters. Furthermore, we show that the Zusman equations, which may be obtained in a semiclassical limit of the reaction coordinate model, are often incapable of describing the correct dynamical behaviour. This demonstrates the necessity of properly accounting for quantum correlations generated between the system and its environment when the Born-Markov approximations no longer hold. Finally, we apply the reaction coordinate formalism to the case of a structured environment comprising of both underdamped (i.e., sharply peaked) and overdamped (broad) components simultaneously. We find that though an enhancement of the dimer energy transfer rate can be obtained when compared to an unstructured environment, its magnitude is rather sensitive to both the dimer-peak resonance conditions and the relative strengths of the underdamped and overdamped contributions.

  7. Complex explosive volcanic activity on the Moon within Oppenheimer crater, Icarus

    Science.gov (United States)

    Bennett, Kristen A; Horgan, Briony H N; Gaddis, Lisa R.; Greenhagen, Benjamin T; Allen, Carlton C.; Hayne, Paul O; Bell, James F III; Paige, David A.

    2016-01-01

    Oppenheimer Crater is a floor-fractured crater located within the South Pole-Aitken basin on the Moon, and exhibits more than a dozen localized pyroclastic deposits associated with the fractures. Localized pyroclastic volcanism on the Moon is thought to form as a result of intermittently explosive Vulcanian eruptions under low effusion rates, in contrast to the higher-effusion rate, Hawaiian-style fire fountaining inferred to form larger regional deposits. We use Lunar Reconnaissance Orbiter Camera images and Diviner Radiometer mid-infrared data, Chandrayaan-1 orbiter Moon Mineralogy Mapper near-infrared spectra, and Clementine orbiter Ultraviolet/Visible camera images to test the hypothesis that the pyroclastic deposits in Oppenheimer crater were emplaced via Vulcanian activity by constraining their composition and mineralogy. Mineralogically, we find that the deposits are variable mixtures of orthopyroxene and minor clinopyroxene sourced from the crater floor, juvenile clinopyroxene, and juvenile iron-rich glass, and that the mineralogy of the pyroclastics varies both across the Oppenheimer deposits as a whole and within individual deposits. We observe similar variability in the inferred iron content of pyroclastic glasses, and note in particular that the northwest deposit, associated with Oppenheimer U crater, contains the most iron-rich volcanic glass thus far identified on the Moon, which could be a useful future resource. We propose that this variability in mineralogy indicates variability in eruption style, and that it cannot be explained by a simple Vulcanian eruption. A Vulcanian eruption should cause significant country rock to be incorporated into the pyroclastic deposit; however, large areas within many of the deposits exhibit spectra consistent with high abundances of juvenile phases and very little floor material. Thus, we propose that at least the most recent portion of these deposits must have erupted via a Strombolian or more continuous fire

  8. Molecular distorted-wave Born approximation for ionization of H2 by electron impact

    International Nuclear Information System (INIS)

    Liu, Junbo; Liu, Dejun; Zhou, Yajun

    2012-01-01

    The molecular distorted-wave Born approximation is proposed to study the (e, 2e) reaction for H 2 targets. The wave functions of the incoming and outgoing electrons are obtained by solving the Lippmann-Schwinger equations, and the T-matrix in the Lippmann-Schwinger equations is calculated in a momentum space static-exchange-optical model. Triple differential cross sections are computed for incident energies of 100 and 250 eV in coplanar asymmetric geometry. Comparison of the present calculated results with the available experimental data in the literature reveals that there is good agreement. (paper)

  9. Subshell stopping power of the elements for protons in the Born approximation

    International Nuclear Information System (INIS)

    McGuire, E.J.

    1982-01-01

    The generalized oscillator-strength formulation of the Born approximation was used to generate a large sample of subshell excitation and ionization generalized oscillator strengths across the periodic table. These were used to calculate the excitation and ionization contributions to the proton stopping power by individual subshells. The subshell ionization stopping powers are expressed in scaled form, depending on the subshell ionization energy. Detailed comparison of the calculated total proton stopping power is in good agreement with experiment across the periodic table. Detailed calculations show the importance of outer-shell ionization and excitation to the total stopping power for protons with energy less than 10 MeV

  10. Second-order Born approximation for the ionization of molecules by electron and positron impact

    Energy Technology Data Exchange (ETDEWEB)

    Dal Cappello, C. [Universite Paul Verlaine-Metz, Laboratoire de Physique Moleculaire et des Collisions, Institut Jean Barriol (FR2843), 1 Boulevard Arago, F-57078 Metz Cedex 3 (France); Rezkallah, Z.; Houamer, S. [Laboratoire de Physique Quantique et Systemes Dynamiques, Departement de Physique, Faculte des Sciences Universite Ferhat Abbas, Setif 19000 (Algeria); Charpentier, I. [Universite Paul Verlaine-Metz, Laboratoire de Physique et Mecanique des Materiaux UMR 7554, Ile du Saulcy, F-57045 Metz Cedex 1 (France); Hervieux, P. A. [Institut de Physique et Chimie des Materiaux de Strasbourg, 23 Rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France); Ruiz-Lopez, M. F. [Nancy-University, Equipe de Chimie et Biochimie Theoriques, UMR CNRS-UHP 7565, BP 239, F-54506 Vandoeuvre-les-Nancy (France); Dey, R. [Max-Planck Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany); Roy, A. C. [School of Mathematical Sciences, Ramakrishna Mission Vivekananda University, Belur Math 711202, West Bengal (India)

    2011-09-15

    Second-order Born approximation is applied to study the ionization of molecules. The initial and final states are described by single-center wave functions. For the initial state a Gaussian wave function is used while for the ejected electron it is a distorted wave. Results of the present model are compared with recent (e,2e) experiments on the water molecule. Preliminary results are also presented for the ionization of the thymine molecule by electrons and positrons.

  11. Large-scale parameter extraction in electrocardiology models through Born approximation

    KAUST Repository

    He, Yuan

    2012-12-04

    One of the main objectives in electrocardiology is to extract physical properties of cardiac tissues from measured information on electrical activity of the heart. Mathematically, this is an inverse problem for reconstructing coefficients in electrocardiology models from partial knowledge of the solutions of the models. In this work, we consider such parameter extraction problems for two well-studied electrocardiology models: the bidomain model and the FitzHugh-Nagumo model. We propose a systematic reconstruction method based on the Born approximation of the original nonlinear inverse problem. We describe a two-step procedure that allows us to reconstruct not only perturbations of the unknowns, but also the backgrounds around which the linearization is performed. We show some numerical simulations under various conditions to demonstrate the performance of our method. We also introduce a parameterization strategy using eigenfunctions of the Laplacian operator to reduce the number of unknowns in the parameter extraction problem. © 2013 IOP Publishing Ltd.

  12. Second Born approximation in elastic-electron scattering from nuclear static electro-magnetic multipoles

    International Nuclear Information System (INIS)

    Al-Khamiesi, I.M.; Kerimov, B.K.

    1988-01-01

    Second Born approximation corrections to electron scattering by nuclei with arbitrary spin are considered. Explicit integral expressions for the charge, magnetic dipole and interference differential cross sections are obtained. Magnetic and interference relative corrections are then investigated in the case of backward electron scattering using shell model form factors for nuclear targets 9 Be, 10 B, and 14 N. To understand exponential growth of these corrections with square of the electron energy K 0 2 , the case of electron scattering by 6 Li is considered using monopole model charge form factor with power-law asymptotics. 11 refs., 2 figs. (author)

  13. Norris Bradbury Tribute by J. Robert Oppenheimer

    Energy Technology Data Exchange (ETDEWEB)

    Meade, Roger Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-04-27

    Stored on a reel of microfilm are three faint and barely readable letters written on the occasion of Norris Bradbury’s fifteen-year anniversary as Director of the (then) Los Alamos Science Laboratory. The first letter, written by Los Alamos Public Relations Officer John V. Young, asks Oppenheimer to send a “congratulatory message to be read at a ceremony honoring Bradbury’s tenure as Laboratory Director. The second letter is Oppenheimer’s response to Young, and the third is Oppenheimer’s congratulatory message to Bradbury. The three letters are transcribed below.

  14. The local quantum-mechanical momentum balance and its consequencies

    International Nuclear Information System (INIS)

    Zieche, P.; Diener, G.; Graafenstejn, J.; Kaschner, R.; Nielsen, O.H.

    1988-01-01

    Many-electron systems are considered within Born-Oppenheimer approximation. The balance equation is derived; its first application concerns force sum rules, involving alternative possibilities for the calculation of relaxation forces. An extended crystal with force-free bulk atoms but under a non-vanishing stress is considered

  15. Semi-quartic force fields retrieved from multi-mode expansions: Accuracy, scaling behavior, and approximations

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishnan, Raghunathan [Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel (Switzerland); Rauhut, Guntram, E-mail: rauhut@theochem.uni-stuttgart.de [Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany)

    2015-04-21

    Semi-quartic force fields (QFF) rely on a Taylor-expansion of the multi-dimensional Born-Oppenheimer potential energy surface (PES) and are frequently used within the calculation of anharmonic vibrational frequencies based on 2nd order vibrational perturbation theory (VPT2). As such they are usually determined by differentiation of the electronic energy with respect to the nuclear coordinates. Alternatively, potential energy surfaces can be expanded in terms of multi-mode expansions, which typically do not require any derivative techniques. The computational effort to retrieve QFF from size-reduced multi-mode expansions has been studied and has been compared with standard Taylor-expansions. As multi-mode expansions allow for the convenient introduction of subtle approximations, these will be discussed in some detail. In addition, a preliminary study about the applicability of a generalized Duschinsky transformation to QFFs is provided. This transformation allows for the efficient evaluation of VPT2 frequencies of isotopologues from the PES of the parent compound and thus avoids the recalculation of PESs in different axes systems.

  16. Born approximation to a perturbative numerical method for the solution of the Schroedinger equation

    International Nuclear Information System (INIS)

    Adam, Gh.

    1978-01-01

    A step function perturbative numerical method (SF-PN method) is developed for the solution of the Cauchy problem for the second order liniar differential equation in normal form. An important point stressed in the present paper, which seems to have been previously ignored in the literature devoted to the PN methods, is the close connection between the first order perturbation theory of the PN approach and the wellknown Born approximation, and, in general, the connection between the varjous orders of the PN corrections and the Neumann series. (author)

  17. Eddington-inspired Born-Infeld gravity: nuclear physics constraints and the validity of the continuous fluid approximation

    Energy Technology Data Exchange (ETDEWEB)

    Avelino, P.P., E-mail: ppavelin@fc.up.pt [Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal)

    2012-11-01

    In this paper we investigate the classical non-relativistic limit of the Eddington-inspired Born-Infeld theory of gravity. We show that strong bounds on the value of the only additional parameter of the theory κ, with respect to general relativity, may be obtained by requiring that gravity plays a subdominant role compared to electromagnetic interactions inside atomic nuclei. We also discuss the validity of the continuous fluid approximation used in this and other astrophysical and cosmological studies. We argue that although the continuous fluid approximation is expected to be valid in the case of sufficiently smooth density distributions, its use should eventually be validated at a quantum level.

  18. Eddington-inspired Born-Infeld gravity: nuclear physics constraints and the validity of the continuous fluid approximation

    International Nuclear Information System (INIS)

    Avelino, P.P.

    2012-01-01

    In this paper we investigate the classical non-relativistic limit of the Eddington-inspired Born-Infeld theory of gravity. We show that strong bounds on the value of the only additional parameter of the theory κ, with respect to general relativity, may be obtained by requiring that gravity plays a subdominant role compared to electromagnetic interactions inside atomic nuclei. We also discuss the validity of the continuous fluid approximation used in this and other astrophysical and cosmological studies. We argue that although the continuous fluid approximation is expected to be valid in the case of sufficiently smooth density distributions, its use should eventually be validated at a quantum level

  19. Bound states of a light atom and two heavy dipoles in two dimensions

    DEFF Research Database (Denmark)

    Rosa, D. S.; Bellotti, F. F.; Jensen, Aksel Stenholm

    2016-01-01

    We study a three-body system, formed by a light particle and two identical heavy dipoles, in two dimensions in the Born-Oppenheimer approximation. We present the analytic light-particle wave function resulting from an attractive zero-range potential between the light and each of the heavy particles...

  20. Collisions of antiprotons with hydrogen molecular ions

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2009-01-01

    Time-dependent close-coupling calculations of the ionization and excitation cross section for antiproton collisions with molecular hydrogen ions are performed in an impact energy range from 0.5 keV to 10 MeV. The Born-Oppenheimer and Franck-Condon approximations as well as the impact parameter...

  1. Distorted-wave Born approximation in the case of an optical scattering potential

    International Nuclear Information System (INIS)

    Mytnichenko, Sergey V.

    2005-01-01

    Application of the distorted-wave Born approximation in the conventional form developed for the case of a real scattering potential is shown to cause significant errors in calculating X-ray diffuse scattering from non-ideal crystals, superlattices, multilayers and other objects if energy dissipation (photoabsorption, inelastic scattering, and so on) is not negligible, or in other words, in the case of an optical (complex) scattering potential. We show how a correct expression for the X-ray diffuse-scattering cross-section can be obtained in this case. Generally, the diffuse-scattering cross-section from an optical potential is not T-invariant, i.e. the reciprocity principle is violated. Violations of T-invariance are more evident when the dynamical nature of the diffraction is more critical

  2. A pion and gluon exchange model of the non-annihilation part of the nucleon-antinucleon interaction

    International Nuclear Information System (INIS)

    Fernandez, F.

    1988-01-01

    The effect of quark antisymmetrization on the one-pion and one-gluon exchange between nucleons and antinucleons is explicitly calculated within the framework of the Born-Oppenheimer approximation. We found an effective short range part of the N-anti N interaction which is repulsive in all the spin-isospin channels. (Author)

  3. Nonadiabatic effects in inelastic collisional processes

    International Nuclear Information System (INIS)

    Belyaev, Andrey K

    2009-01-01

    The standard adiabatic Born-Oppenheimer approach to inelastic collisional processes is revised. It is shown that the widely used standard interpretation of this approach has fundamental limitations leading to physical artefacts or to uncertainties in numerical calculations due to neglecting the electron translation problem. It is demonstrated that the Born-Oppenheimer approach itself does not have such limitations. The particular full quantum solution of the electron translation problem within the Born-Oppenheimer approach by means of the reprojection procedure is discussed in the paper together with the practical applications.

  4. Beyond Born-Oppenheimer theory for ab initio constructed diabatic potential energy surfaces of singlet H3+ to study reaction dynamics using coupled 3D time-dependent wave-packet approach.

    Science.gov (United States)

    Ghosh, Sandip; Mukherjee, Saikat; Mukherjee, Bijit; Mandal, Souvik; Sharma, Rahul; Chaudhury, Pinaki; Adhikari, Satrajit

    2017-08-21

    The workability of beyond Born-Oppenheimer theory to construct diabatic potential energy surfaces (PESs) of a charge transfer atom-diatom collision process has been explored by performing scattering calculations to extract accurate integral cross sections (ICSs) and rate constants for comparison with most recent experimental quantities. We calculate non-adiabatic coupling terms among the lowest three singlet states of H 3 + system (1 1 A ' , 2 1 A ' , and 3 1 A ' ) using MRCI level of calculation and solve the adiabatic-diabatic transformation equation to formulate the diabatic Hamiltonian matrix of the same process [S. Mukherjee et al., J. Chem. Phys. 141, 204306 (2014)] for the entire region of nuclear configuration space. The nonadiabatic effects in the D + + H 2 reaction has been studied by implementing the coupled 3D time-dependent wave packet formalism in hyperspherical coordinates [S. Adhikari and A. J. C. Varandas, Comput. Phys. Commun. 184, 270 (2013)] with zero and non-zero total angular momentum (J) on such newly constructed accurate (ab initio) diabatic PESs of H 3 + . We have depicted the convergence profiles of reaction probabilities for the reactive non-charge transfer, non-reactive charge transfer, and reactive charge transfer processes for different collisional energies with respect to the helicity (K) and total angular momentum (J) quantum numbers. Finally, total and state-to-state ICSs are calculated as a function of collision energy for the initial rovibrational state (v = 0, j = 0) of the H 2 molecule, and consequently, those quantities are compared with previous theoretical and experimental results.

  5. The story of an A-bomb by Oppenheimer

    International Nuclear Information System (INIS)

    Song, Eun Yeong

    2005-06-01

    This book concentrates on an A-bomb by Oppenheimer. It is divided into eleven class, which are exile of excellent scientists, uranium atomic fission, situation the U.S. and Germany I, situation the U.S. and Germany II, air strike in pearl Harbor, plan for development of an A-bomb, military action to blow up heavy water plant, select on spot to drop an A-bomb, surrender and drop for an A-bomb and science of an A-bomb. This book is written to explain an A-bomb with form of storytelling.

  6. The story of an A-bomb by Oppenheimer

    Energy Technology Data Exchange (ETDEWEB)

    Song, Eun Yeong

    2005-06-15

    This book concentrates on an A-bomb by Oppenheimer. It is divided into eleven class, which are exile of excellent scientists, uranium atomic fission, situation the U.S. and Germany I, situation the U.S. and Germany II, air strike in pearl Harbor, plan for development of an A-bomb, military action to blow up heavy water plant, select on spot to drop an A-bomb, surrender and drop for an A-bomb and science of an A-bomb. This book is written to explain an A-bomb with form of storytelling.

  7. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 66; Issue 2. Volume 66, Issue 2. February 2006, pages 313-478. pp 313-324 Research Articles. A new algorithm for anisotropic solutions · M Chaisi S D .... Coulomb-Born-Oppenheimer approximation in Ps-H scattering · Hasi Ray · More Details Abstract Fulltext PDF.

  8. Force-Field Functor Theory: Classical Force-Fields which Reproduce Equilibrium Quantum Distributions

    Directory of Open Access Journals (Sweden)

    Ryan eBabbush

    2013-10-01

    Full Text Available 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.

  9. Next Generation Extended Lagrangian Quantum-based Molecular Dynamics

    Science.gov (United States)

    Negre, Christian

    2017-06-01

    A new framework for extended Lagrangian first-principles molecular dynamics simulations is presented, which overcomes shortcomings of regular, direct Born-Oppenheimer molecular dynamics, while maintaining important advantages of the unified extended Lagrangian formulation of density functional theory pioneered by Car and Parrinello three decades ago. The new framework allows, for the first time, energy conserving, linear-scaling Born-Oppenheimer molecular dynamics simulations, which is necessary to study larger and more realistic systems over longer simulation times than previously possible. Expensive, self-consinstent-field optimizations are avoided and normal integration time steps of regular, direct Born-Oppenheimer molecular dynamics can be used. Linear scaling electronic structure theory is presented using a graph-based approach that is ideal for parallel calculations on hybrid computer platforms. For the first time, quantum based Born-Oppenheimer molecular dynamics simulation is becoming a practically feasible approach in simulations of +100,000 atoms-representing a competitive alternative to classical polarizable force field methods. In collaboration with: Anders Niklasson, Los Alamos National Laboratory.

  10. Few-body quark dynamics for doubly heavy baryons and tetraquarks

    Science.gov (United States)

    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.

  11. Bond selective chemistry beyond the adiabatic approximation

    Energy Technology Data Exchange (ETDEWEB)

    Butler, L.J. [Univ. of Chicago, IL (United States)

    1993-12-01

    One of the most important challenges in chemistry is to develop predictive ability for the branching between energetically allowed chemical reaction pathways. Such predictive capability, coupled with a fundamental understanding of the important molecular interactions, is essential to the development and utilization of new fuels and the design of efficient combustion processes. Existing transition state and exact quantum theories successfully predict the branching between available product channels for systems in which each reaction coordinate can be adequately described by different paths along a single adiabatic potential energy surface. In particular, unimolecular dissociation following thermal, infrared multiphoton, or overtone excitation in the ground state yields a branching between energetically allowed product channels which can be successfully predicted by the application of statistical theories, i.e. the weakest bond breaks. (The predictions are particularly good for competing reactions in which when there is no saddle point along the reaction coordinates, as in simple bond fission reactions.) The predicted lack of bond selectivity results from the assumption of rapid internal vibrational energy redistribution and the implicit use of a single adiabatic Born-Oppenheimer potential energy surface for the reaction. However, the adiabatic approximation is not valid for the reaction of a wide variety of energetic materials and organic fuels; coupling between the electronic states of the reacting species play a a key role in determining the selectivity of the chemical reactions induced. The work described below investigated the central role played by coupling between electronic states in polyatomic molecules in determining the selective branching between energetically allowed fragmentation pathways in two key systems.

  12. Asymptotically-correct description of vibration-rotation spectrum of diatomic molecule with hydrogen iodide molecule as example

    International Nuclear Information System (INIS)

    Burenin, A.V.; Ryabikin, M.Yu.

    1990-01-01

    Asymptotically correct series of perturbation theory was constructed analytically to describe the vibration-rotational spectrum of diatomic molecule in Born-Oppenheimer approximation. The series was used for processing of precision experimental data on frequencies of absorption of hydrogen iodide molecule. Advantage of this approach over Dunham approach is shown. Isotope ratios for spectroscopic constants of asymptotically correct series are considered

  13. Molecules as quantum shapes and how they violate P and T

    International Nuclear Information System (INIS)

    Balachandran, A.P.; Witt, D.M.; Simoni, A.

    1992-01-01

    A geometric shape is a rigid shape in n-dimensional Euclidean space. These shapes commonly occur in the Born-Oppenheimer approximation in molecular physics, and collective models of nuclei. Abelian and non-Abelian generalizations of the of the vacuum angle of gauge theories are realized in the quantum theory of shapes. In this paper, such generalizations are presented in the language of modern quantum physics and it is shown that parity, P, and time reversal, T, are violated in certain of these quantum theories. However, the combined symmetry PT of parity composed with time reversal generally remains a good symmetry, just as in gauge theories. The exceptions are the quantum theories of staggered conformations which can violate only T. The mechanism responsible for the loss of these symmetries is a generalization of the vacuum angle mechanism for the same effect. An important results of the present analysis is the demonstration that geometric shapes, molecules in the Born-Oppenheimer approximation, and nuclei in the collective model description furnish concrete systems which upon quantization discriminate between left- and right-handed coordinates even though this distinction is entirely absent in their classical descriptions

  14. Electron-hydrogen atom collisions in the presence of a laser field

    International Nuclear Information System (INIS)

    Brandi, H.S.; Koiller, B.; Barros, H.G.P.L. de

    1978-01-01

    The collision of an electron and a hydrogen atom in the presence of a laser field is studied within a previously proposed approximation (based on the space translation approximation) for the bound states of the hydrogen atom. Fhe Green's function formalism is applied to derive an expression for the scattering amplitude associated to multiphoton processes. The Born-Oppenheimer approximation is obtained and numerical calculations are performed for the ls→2s inelastic excitation. It is shown as expected that exchange effects are important only for scattering processes involving low energy electrons [pt

  15. Three-body molecular description of 9Be

    International Nuclear Information System (INIS)

    Revai, J.; Matveenko, A.V.

    1979-01-01

    The low lying spectrum of the 9 Be nucleus is calculated in the α+α+n three-body model. The molecular approach to this three-body problem based on the exact evalution of the two-center wave functions for separable n-α potentials is considered in detail. The numerical results are obtained in the generalized Born-Oppenheimer approximation which preserves total angular momentum and parity

  16. Eddy current imaging. Limits of the born approximation and advantages of an exact solution to the inverse problem

    International Nuclear Information System (INIS)

    Hamman, E.; Zorgati, R.

    1995-01-01

    Eddy current non-destructive testing is used by EDF to detect flaws affecting conductive objects such as steam generator tubes. With a view to obtaining ever more accurate information on equipment integrity, thereby facilitating diagnosis, studies aimed at using measurements to reconstruct an image of the flaw have been proceeding now for about ten years. In this context, our approach to eddy current imaging is based on inverse problem formalism. The direct problem, involving a mathematical model linking measurements provided by a probe with variables characterizing the defect, is dealt with elsewhere. Using the model results, we study the possibility of inverting it, i.e. of reconstructing an image of the flaw from the measurements. We first give an overview of the different inversion techniques, representative of the state of the art and all based on linearization of the inverse problem by means of the Born approximation. The model error resulting from an excessive Born approximation nevertheless severely limits the quantity of the images which can be obtained. In order to counteract this often critical error and extend the eddy current imaging application field, we have to del with the non-linear inverse problem. A method derived from recent research is proposed and implemented to ensure consistency with the exact model. Based on an 'optimization' type approach and provided with a convergence theorem, the method is highly efficient. (authors). 17 refs., 7 figs., 1 append

  17. Nuclear fusion rate of the muonic T3 molecule

    International Nuclear Information System (INIS)

    Faghihi, F.; Eskandari, M. R.

    2004-01-01

    The ground state binding energy, size and effective nuclear charge of the muonic T 3 molecule are calculated using Born-Oppenheimer adiabatic approximation. The system possesses two minimum positions, one at typically muonic and the second at the atomic distances. A symmetric planar vibrational model between two minima is assumed and the approximated potential are calculated. Moreover, nuclear fusion rate calculations of the short-life molecule is carried out due to the overlap integral of the resonance nuclear compound nucleus and the molecular wave functions

  18. Unusual Phenotype of the Brownell-Oppenheimer Variant of Sporadic Creutzfeldt-Jakob Disease

    Directory of Open Access Journals (Sweden)

    Dronacharya Lamichhane

    2016-03-01

    Full Text Available Creutzfeldt-Jakob disease is a rare, transmissible, neurodegenerative disease caused by conformationally changed abnormal prion protein. Most patients present with cognitive impairment, myoclonus, ataxia, visual impairment alone or in combination. Patients who present with ataxia only at the onset are said to have Brownell-Oppenheimer variant of the disease. However, here we present a case where visual symptoms preceded the clinical presentation and hallucinations accompanied the ataxia at the onset of the disease.

  19. Three-atom clusters

    International Nuclear Information System (INIS)

    Pen'kov, F.M.

    1998-01-01

    The Born-Oppenheimer approximation is used to obtain an equation for the effective interaction in three atoms bound by a single electron. For low binding energies in an 'electron + atom' pair, long-range forces arise between the atoms, leading to bound states when the size of the three-atom cluster is a few tens of angstrom. A system made of alkali-metal atoms is considered as an example

  20. Appplications of the post-Tolman-Oppenheimer-Volkoff formalism

    Science.gov (United States)

    Silva, Hector O.; Glampedakis, Kostas; Pappas, George; Berti, Emanuele

    2017-01-01

    Besides their astrophysical interest, neutron stars are promising candidates for testing theories of gravity in the strong-field regime. It is known that, generically, modifications to general relativity affect the bulk properties of neutron stars, e.g. their masses and radii, in a way that depends on the specific choice of theory. In this presentation we review a theory-agnostic approach to model relativistic stars, called the post-Tolman-Oppenheimer-Volkoff formalism. Drawing inspiration from the parametrized post-Newtonian formalism, this framework allows us to describe perturbative deviations from general relativity in the structure of neutrons stars in a parametrized manner. We show that a variety of astrophysical observables (namely the surface redshift, the apparent radius, the Eddington luminosity and the orbital frequency of particles in geodesic motion around neutron stars) can be parametrized using only two parameters.

  1. Electron capture by alpha particles from helium atoms in a Coulomb-Born distorted-wave approximation

    International Nuclear Information System (INIS)

    Ghanbari-Adivi, E; Ghavaminia, H

    2012-01-01

    A three-body Coulomb-Born continuum distorted-wave approximation is applied to calculate the differential and total cross sections for single-electron exchange in the collision of fast alpha particles with helium atoms in their ground states. The applied first-order distorted wave theory satisfies correct Coulomb boundary conditions. Both post and prior forms of the transition amplitude are calculated. The nuclear-screening effect of the passive electron on the differential and total cross sections is investigated. The results are compared with those of other theories and with the available experimental data. For differential cross sections, the comparisons show a reasonable agreement with empirical measurements at higher impact energies. The agreement between experimental data and the present calculations for total cross sections with the average of the post and prior forms of the transition amplitude is reasonable at all the specified energies.

  2. The coupled-channel T-matrix: its lowest-order Born + Lanczos approximants

    International Nuclear Information System (INIS)

    Znojil, M.

    1995-01-01

    Three iterative methods of solution of the Lippmann-Schwinger equations (viz., the method of continued fractions by J.Horacek and T.Sasakawa), its Born-remainder modification and a coupled-channel matrix-continued-fraction generalization are all interpreted as special cases of a common iterative matrix prescription. Firstly, in terms of certain asymmetric projectors P≠P + , we re-derive the three particular older methods as different realizations of the well-known Lanczos inversion. Then, a generalized iteration method is proposed as a Born-like re-arrangement of any intermediate Lanczos iteration step. A maximal flexibility is achieved in the formalism which might compete with the standard Pade re-summations in practice. Its first few truncations are listed, therefore. 26 refs., 1 tab

  3. H2+ embedded in a Debye plasma: Electronic and vibrational properties

    OpenAIRE

    Angel, M. L.; Montgomery Jr, H. E.

    2010-01-01

    The effect of plasma screening on the electronic and vibrational properties of the H2+ molecular ion was analyzed within the Born-Oppenheimer approximation. When a molecule is embedded in a plasma, the plasma screens the electrostatic interactions. This screening is accounted for in the Schr\\"odinger equation by replacing the Coulomb potentials with Yukawa potentials that incorporate the Debye length as a screening parameter. Variational expansions in confocal elliptical coordinates were used...

  4. Born-Oppenheimer Dynamics, Electronic Friction, and the Inclusion of Electron-Electron Interactions

    Science.gov (United States)

    Dou, Wenjie; Miao, Gaohan; Subotnik, Joseph E.

    2017-07-01

    We present a universal expression for the electronic friction as felt by a set of classical nuclear degrees of freedom (DOFs) coupled to a manifold of quantum electronic DOFs; no assumptions are made regarding the nature of the electronic Hamiltonian and electron-electron repulsions are allowed. Our derivation is based on a quantum-classical Liouville equation for the coupled electronic-nuclear motion, followed by an adiabatic approximation whereby electronic transitions are assumed to equilibrate faster than nuclear movement. The resulting form of friction is completely general, but does reduce to previously published expressions for the quadratic Hamiltonian (i.e., Hamiltonians without electronic correlation). At equilibrium, the second fluctuation-dissipation theorem is satisfied and the frictional matrix is symmetric. To demonstrate the importance of electron-electron correlation, we study electronic friction within the Anderson-Holstein model, where a proper treatment of electron-electron interactions shows signatures of a Kondo resonance and a mean-field treatment is completely inadequate.

  5. Oppenheimer&Groves : The duality that led to Trinity /.

    Energy Technology Data Exchange (ETDEWEB)

    Connaughton, T. G. (Theresa G.); Smith, S. E. (Sharon E.)

    2001-01-01

    The alliance of J. Robert Oppenheimer, scientist, and Leslie R. Groves, military leader, is often interpreted as the classic example of the clash between the academic mind and the military style. Evidence suggests, instead, that it was a collaboration that led to the dawn of the nuclear age. Instead of a clash, it was collaboration and an implosion of the diverse talents needed for the success of this project. Discussion of these flawed and fascinating individuals still ignites controversy today. This presentation will explore the backgrounds and personalities of these two men and their work together to accomplish their mission. Was the aftermath inevitable, given a relationship based on respect, but perhaps not trust? The genesis of the modern military-industrial complex rested on the genius of these two men, though they personify two distinct American sub-cultures. What lessons can be drawn from their wartime and post-war relationship? What analogies can be drawn for current American values?

  6. Recoil saturation of the self-energy in atomic systems

    International Nuclear Information System (INIS)

    Manson, J.R.; Ritchie, R.H.

    1988-01-01

    Within the framework of the general self-energy problem for the interaction of a projectile with a many-body system, we consider the dispersion force between two atoms or between a charge and an atom. Since the Born-Oppenheimer approximation is not made, this is a useful approach for exhibiting non-adiabatic effects. We find compact expressions in terms of matrix elements of operators in the atomic displacement which are not limited by multipole expansions. 7 refs

  7. Coherent structural trapping through wave packet dispersion during photoinduced spin state switching

    DEFF Research Database (Denmark)

    Lemke, Henrik T.; Kjær, Kasper Skov; Hartsock, Robert

    2017-01-01

    The description of ultrafast nonadiabatic chemical dynamics during molecular photo-transformations remains challenging because electronic and nuclear configurations impact each other and cannot be treated independently. Here we gain experimental insights, beyond the Born-Oppenheimer approximation...... is distinguished from the structural trapping dynamics, which launches a coherent oscillating wave packet (265 fs period), clearly identified as molecular breathing. Throughout the structural trapping, the dispersion of the wave packet along the reaction coordinate reveals details of intramolecular vibronic...

  8. Interpreting the Coulomb-field approximation for generalized-Born electrostatics using boundary-integral equation theory.

    Science.gov (United States)

    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

  9. Quantum gravitational contributions to the cosmic microwave background anisotropy spectrum.

    Science.gov (United States)

    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.

  10. The off-resonant aspects of decoherence and a critique of the two-level approximation

    International Nuclear Information System (INIS)

    Savran, Kerim; Hakioglu, T; Mese, E; Sevincli, Haldun

    2006-01-01

    exponential independently from the number of levels. The latter and the coupling strengths play the major role in the quantitative values of the rates and the rates are independent of the other spectral parameters. The validity of the presented results is restricted only by their reliance on the Born-Oppenheimer approximation. This approximation is strongly dependent on the external observational time and its reliability depends on an additional timescale. In the rest of the work, the crossover between the short and the long time behaviour of the density matrix of the multilevelled system is examined using an intuitive argument. It is shown that the Born approximation weakens as the resonant couplings become more effective at long times. This implies that, in calculations made with this approximation in the long time regime, a need for a justification arises for the reliability of the results. This justification is made for the present work

  11. Non-Born-Oppenheimer Spectroscopy of Cyclic Triatomics

    Science.gov (United States)

    2011-10-11

    n nmnm mn m nm nm nm nm ss n IV E 2/ if,2/1 2/ if, ])2/1()/[( )2/1()/( 2 1 12 22 222 22 2/,,4 23 )3(   Here ZPE ...integer values of m . The perturbation theory expression gives us seven parameters for a non-linear fitting problem: ZPE , 0I , 1I , 2I , 3V , 6V and

  12. Finite-rank potential that reproduces the Pade approximant

    International Nuclear Information System (INIS)

    Tani, S.

    1979-01-01

    If a scattering potential is of a finite rank, say N, the exact solution of the problem can be obtained from the Born series, if the potential strength is within the radius of convergence; the exact solution can be obtained from the analytical continuation of the formal Born series outside the radius of convergence. Beyond the first 2N terms of the Born series, an individual term of the Born series depends on the first 2N terms, and the [N/N] Pade approximant and the exact solution agree with each other. The above-mentioned features of a finite-rank problem are relevant to scattering theory in general, because most scattering problems may be handled as an extension of the rank-N problem, in which the rank N tends to infinity. The foregoing aspects of scattering theory will be studied in depth in the present paper, and in so doing we proceed in the opposite direction. Namely, given a potential, we calculate the first 2N terms of the Born series for the K matrix and the first N terms of the Born series for the wave function. Using these data, a special rank-N potential is constructed in such a way that it reproduces the [N/N] Pade approximant of the K matrix of the original scattering problem. One great advantage of obtaining such a rank-N potential is that the wave function of the system may be approximated in the same spirit as done for the K matrix; hence, we can introduce a new approximation method for dealing with an off-shell T matrix. A part of the mathematical work is incomplete, but the physical aspects are thoroughly discussed

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

    Science.gov (United States)

    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.

  14. The He+H¯→He p¯+e+ rearrangement

    Science.gov (United States)

    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].

  15. The He+H-bar → Hep-bar +e+ rearrangement

    International Nuclear Information System (INIS)

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

    2006-01-01

    In this paper, we present a summary of our work in progress on calculating cross sections for the He+H-bar ->Hep-bar +e + rearrangement process in HeH-bar scattering. This has involved a study of the system Hep-bar 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-bar 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

  16. Astrophysical applications of the post-Tolman-Oppenheimer-Volkoff formalism

    Science.gov (United States)

    Glampedakis, Kostas; Pappas, George; Silva, Hector O.; Berti, Emanuele

    2016-08-01

    The bulk properties of spherically symmetric stars in general relativity can be obtained by integrating the Tolman-Oppenheimer-Volkoff (TOV) equations. In previous work [K. Glampedakis, G. Pappas, H. O. Silva, and E. Berti, Phys. Rev. D 92, 024056 (2015)], we developed a "post-TOV" formalism—inspired by parametrized post-Newtonian theory—which allows us to classify in a parametrized, phenomenological form all possible perturbative deviations from the structure of compact stars in general relativity that may be induced by modified gravity at second post-Newtonian order. In this paper we extend the formalism to deal with the stellar exterior, and we compute several potential astrophysical observables within the post-TOV formalism: the surface redshift zs, the apparent radius Rapp, the Eddington luminosity at infinity LE∞ and the orbital frequencies. We show that, at leading order, all of these quantities depend on just two post-TOV parameters μ1 and χ , and we discuss the possibility to measure (or set upper bounds on) these parameters.

  17. Stepping out of homogeneity in loop quantum cosmology

    International Nuclear Information System (INIS)

    Rovelli, Carlo; Vidotto, Francesca

    2008-01-01

    We explore the extension of quantum cosmology outside the homogeneous approximation using the formalism of loop quantum gravity. We introduce a model where some of the inhomogeneous degrees of freedom are present, providing a tool for describing general fluctuations of quantum geometry near the initial singularity. We show that the dynamical structure of the model reduces to that of loop quantum cosmology in the Born-Oppenheimer approximation. This result corroborates the assumptions that ground loop cosmology sheds some light on the physical and mathematical relation between loop cosmology and full loop quantum gravity, and on the nature of the cosmological approximation. Finally, we show that the non-graph-changing Hamiltonian constraint considered in the context of algebraic quantum gravity provides a viable effective dynamics within this approximation

  18. Quantum chaos induced by nonadiabatic coupling in wave-packet dynamics

    International Nuclear Information System (INIS)

    Higuchi, Hisashi; Takatsuka, Kazuo

    2002-01-01

    The effect of nonadiabatic coupling due to breakdown of the Born-Oppenheimer approximation on chaos is investigated. A couple of measures (indicators) that detect the extent of chaos in wave-packet dynamics on coupled potential functions are devised. Using them, we show that chaos is indeed induced by a nonadiabatic coupling in individual time-dependent wave-packet dynamics. This chaos is genuinely of quantum nature, since it arises from bifurcation and merging of a wave packet at the quasicrossing region of two coupled potential functions

  19. The generator coordinate method in nuclear physics

    International Nuclear Information System (INIS)

    Giraud, B.G.

    1981-01-01

    The generator coordinate method is introduced as a physical description of a N-body system in a subspace of a reduced number of degrees of freedom. Special attention is placed on the identification of these special, 'collective' degrees of freedom. It is shown in particular that the method has close links with the Born-Oppenheimer approximation and also that considerations of differential geometry are useful in the theory. A set of applications is discussed and in particular the case of nuclear collisions is considered. (Author) [pt

  20. Multidimensional effects on dissociation of N-2 on Ru(0001)

    DEFF Research Database (Denmark)

    Diaz, C.; Vincent, J.K.; Krishnamohan, G.P.

    2006-01-01

    on density functional theory. The computed reaction probabilities are in good agreement with molecular beam experiments. Comparison to previous calculations shows that the rotation of N-2 and its motion along the surface affect the reactivity of N-2 much more than nonadiabatic effects.......The applicability of the Born-Oppenheimer approximation to molecule-metal surface reactions is presently a topic of intense debate. We have performed classical trajectory calculations on a prototype activated dissociation reaction, of N-2 on Ru(0001), using a potential energy surface based...

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

    Science.gov (United States)

    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.

  2. Vibrationally averaged dipole moments of methane and benzene isotopologues

    Energy Technology Data Exchange (ETDEWEB)

    Arapiraca, A. F. C. [Laboratório de Átomos e Moléculas Especiais, Departamento de Física, ICEx, Universidade Federal de Minas Gerais, P. O. Box 702, 30123-970 Belo Horizonte, MG (Brazil); Centro Federal de Educação Tecnológica de Minas Gerais, Coordenação de Ciências, CEFET-MG, Campus I, 30.421-169 Belo Horizonte, MG (Brazil); Mohallem, J. R., E-mail: rachid@fisica.ufmg.br [Laboratório de Átomos e Moléculas Especiais, Departamento de Física, ICEx, Universidade Federal de Minas Gerais, P. O. Box 702, 30123-970 Belo Horizonte, MG (Brazil)

    2016-04-14

    DFT-B3LYP post-Born-Oppenheimer (finite-nuclear-mass-correction (FNMC)) calculations of vibrationally averaged isotopic dipole moments of methane and benzene, which compare well with experimental values, are reported. For methane, in addition to the principal vibrational contribution to the molecular asymmetry, FNMC accounts for the surprisingly large Born-Oppenheimer error of about 34% to the dipole moments. This unexpected result is explained in terms of concurrent electronic and vibrational contributions. The calculated dipole moment of C{sub 6}H{sub 3}D{sub 3} is about twice as large as the measured dipole moment of C{sub 6}H{sub 5}D. Computational progress is advanced concerning applications to larger systems and the choice of appropriate basis sets. The simpler procedure of performing vibrational averaging on the Born-Oppenheimer level and then adding the FNMC contribution evaluated at the equilibrium distance is shown to be appropriate. Also, the basis set choice is made by heuristic analysis of the physical behavior of the systems, instead of by comparison with experiments.

  3. Vacancy-rearrangement theory in the first Magnus approximation

    International Nuclear Information System (INIS)

    Becker, R.L.

    1984-01-01

    In the present paper we employ the first Magnus approximation (M1A), a unitarized Born approximation, in semiclassical collision theory. We have found previously that the M1A gives a substantial improvement over the first Born approximation (B1A) and can give a good approximation to a full coupled channels calculation of the mean L-shell vacancy probability per electron, p/sub L/, when the L-vacancies are accompanied by a K-shell vacancy (p/sub L/ is obtained experimentally from measurements of K/sub α/-satellite intensities). For sufficiently strong projectile-electron interactions (sufficiently large Z/sub p/ or small v) the M1A ceases to reproduce the coupled channels results, but it is accurate over a much wider range of Z/sub p/ and v than the B1A. 27 references

  4. Quantitative assessment of submicron scale anisotropy in tissue multifractality by scattering Mueller matrix in the framework of Born approximation

    Science.gov (United States)

    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.

  5. The A=3 Nolen-Schiffer anomaly and the up-down quark mass difference

    International Nuclear Information System (INIS)

    Encinosa, M.; Robson, D.

    1990-01-01

    A recently proposed nonrelativistic many-body quark model is used to generate class III nucleon-nucleon potentials in a Born-Oppenheimer approach. These potentials, when treated in first-order perturbation theory with a simple ansatz for the three-nucleon wave function, allow us to make an estimate of the 3 He- 3 H mass difference. For accepted values of the constituent up-down quark mass difference we find that approximately sixty percent of the A=3 Nolen-Schiffer anomaly can be accounted for solely from the up-down quark kinetic energy difference. (orig.)

  6. On the influence of molecular structure on the conductivity of electrolyte solutions - sodium nitrate in water

    Directory of Open Access Journals (Sweden)

    H. Krienke

    2013-01-01

    Full Text Available Theoretical calculations of the conductivity of sodium nitrate in water are presented and compared with experimental measurements. The method of direct correlation force in the framework of the interionic theory is used for the calculation of transport properties in connection with the associative mean spherical approximation (AMSA. The effective interactions between ions in solutions are derived with the help of Monte Carlo and Molecular Dynamics calculations on the Born-Oppenheimer level. This work is based on earlier theoretical and experimental studies of the structure of concentrated aqueous sodium nitrate solutions.

  7. The (e,2e) reaction in molecules

    International Nuclear Information System (INIS)

    Dey, S.; Dixon, A.; Teubner, P.J.O.; Weigold, E.

    1975-01-01

    The aplication of the (e,2e) technique is discussed in the framework of (e,2e) on molecular hydrogen. It is shown that the technique is sufficiently sensitive to distinguish between simple wavefunctions and those containing configuration interactions. By comparing the data on H 2 and D 2 is shown that the Born-Oppenheimer approximation is confirmed to an accuracy of about 3 per cent. The data is also used to contrast other methods of determining electron momentum distributions in molecules. Data on methane, carbon monoxide and molecular nitrogen is also presented. (author)

  8. Forward modeling of space-borne gravitational wave detectors

    International Nuclear Information System (INIS)

    Rubbo, Louis J.; Cornish, Neil J.; Poujade, Olivier

    2004-01-01

    Planning is underway for several space-borne gravitational wave observatories to be built in the next 10 to 20 years. Realistic and efficient forward modeling will play a key role in the design and operation of these observatories. Space-borne interferometric gravitational wave detectors operate very differently from their ground-based counterparts. Complex orbital motion, virtual interferometry, and finite size effects complicate the description of space-based systems, while nonlinear control systems complicate the description of ground-based systems. Here we explore the forward modeling of space-based gravitational wave detectors and introduce an adiabatic approximation to the detector response that significantly extends the range of the standard low frequency approximation. The adiabatic approximation will aid in the development of data analysis techniques, and improve the modeling of astrophysical parameter extraction

  9. Piecewise linear approximations to model the dynamics of adaptation to osmotic stress by food-borne pathogens.

    Science.gov (United States)

    Métris, Aline; George, Susie M; Ropers, Delphine

    2017-01-02

    Addition of salt to food is one of the most ancient and most common methods of food preservation. However, little is known of how bacterial cells adapt to such conditions. We propose to use piecewise linear approximations to model the regulatory adaptation of Escherichiacoli to osmotic stress. We apply the method to eight selected genes representing the functions known to be at play during osmotic adaptation. The network is centred on the general stress response factor, sigma S, and also includes a module representing the catabolic repressor CRP-cAMP. Glutamate, potassium and supercoiling are combined to represent the intracellular regulatory signal during osmotic stress induced by salt. The output is a module where growth is represented by the concentration of stable RNAs and the transcription of the osmotic gene osmY. The time course of gene expression of transport of osmoprotectant represented by the symporter proP and of the osmY is successfully reproduced by the network. The behaviour of the rpoS mutant predicted by the model is in agreement with experimental data. We discuss the application of the model to food-borne pathogens such as Salmonella; although the genes considered have orthologs, it seems that supercoiling is not regulated in the same way. The model is limited to a few selected genes, but the regulatory interactions are numerous and span different time scales. In addition, they seem to be condition specific: the links that are important during the transition from exponential to stationary phase are not all needed during osmotic stress. This model is one of the first steps towards modelling adaptation to stress in food safety and has scope to be extended to other genes and pathways, other stresses relevant to the food industry, and food-borne pathogens. The method offers a good compromise between systems of ordinary differential equations, which would be unmanageable because of the size of the system and for which insufficient data are available

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  12. Electron-nuclear dynamics of molecular systems

    International Nuclear Information System (INIS)

    Diz, A.; Oehrn, Y.

    1994-01-01

    The content of an ab initio time-dependent theory of quantum molecular dynamics of electrons and atomic nuclei is presented. Employing the time-dependent variational principle and a family of approximate state vectors yields a set of dynamical equations approximating the time-dependent Schroedinger equation. These equations govern the time evolution of the relevant state vector parameters as molecular orbital coefficients, nuclear positions, and momenta. This approach does not impose the Born-Oppenheimer approximation, does not use potential energy surfaces, and takes into account electron-nuclear coupling. Basic conservation laws are fully obeyed. The simplest model of the theory employs a single determinantal state for the electrons and classical nuclei and is implemented in the computer code ENDyne. Results from this ab-initio theory are reported for ion-atom and ion-molecule collisions

  13. Slow collisions between identical atoms in a laser field: Application of the Born and Markov approximations to the system of moving atoms

    International Nuclear Information System (INIS)

    Trippenbach, M.; Gao, B.; Cooper, J.; Burnett, K.

    1992-01-01

    We have derived reduced-density-matrix equations of motion for a pair of two identical atoms moving in the radiation field as the first step in establishing a theory of collisional redistribution of light from neutral-atom traps. We use the Zwanzig projection-operator technique to average over spontaneous field modes and establish the conditions under which Born and Markov approximations can be applied to the system of moving atoms. It follows from these considerations that when these conditions hold, the reduced-density-matrix equation for moving atoms has the same form as that for the stationary case: time dependence is introduced into the decay rates and interaction potentials by making the substitution R=R(t)

  14. Charge and finite size corrections for virtual photon spectra in second order Born approximation

    International Nuclear Information System (INIS)

    Durgapal, P.

    1982-01-01

    The purpose of this work is to investigate the effects of finite nuclear size and charge on the spectrum of virtual photons emitted when a relativistic electron is scattered in the field of an atomic nucleus. The method consisted in expanding the scattering cross section in terms of integrals over the nuclear inelastic form factor with a kernel which was evaluated in second order Born approximation and was derived from the elastic-electron scattering form factor. The kernel could be evaluated analytically provided the elastic form factor contained only poles. For this reason the author used a Yukawa form factor. Before calculating the second order term the author studied the first order term containing finite size effects in the inelastic form factor. The author observed that the virtual photon spectrum is insensitive to the details of the inelastic distribution over a large range of energies and depends only on the transition radius. This gave the author the freedom of choosing an inelastic distribution for which the form factor has only poles and the author chose a modified form of the exponential distribution, which enabled the author to evaluate the matrix element analytically. The remaining integral over the physical momentum transfer was performed numerically. The author evaluated the virtual photon spectra for E1 and M1 transitions for a variety of electron energies using several nuclei and compared the results with the distorted wave calculations. Except for low energy and high Z, the second order results compared well with the distorted wave calculations

  15. A new vibrational level of the H2+ molecular ion

    International Nuclear Information System (INIS)

    Carbonell, J.; Lazauskas, R.; Delande, D.; Hilico, L.; Kilic, S.; Hilico, L.; Kilic, S.

    2003-01-01

    A new vibrational level of the molecular ion H 2 + with binding energy of 1.09 x 10 -9 a.u. ∼ 30 neV below the first dissociation limit is predicted, using highly accurate numerical non-relativistic quantum calculations, which go beyond the Born-Oppenheimer approximation. It is the first-excited vibrational level v=1 of the 2pσ u electronic state, antisymmetric with respect to the exchange of the two protons, with orbital angular momentum L=0. It manifests itself as a huge p - H scattering length of a = 750 ± 5 Bohr radii. (authors)

  16. Effect of nucleon and hadron structure changes in-medium and its impact on observables

    Energy Technology Data Exchange (ETDEWEB)

    K. Saito; K. Tsushima; A.W. Thomas

    2005-07-05

    We study the effect of hadron structure changes in a nuclear medium using the quark-meson coupling (QMC) model. The QMC model is based on a mean field description of non-overlapping nucleon (or baryon) bags bound by the self-consistent exchange of scalar and vector mesons in the isoscalar and isovector channels. The model is extended to investigate the properties of finite nuclei, in which, using the Born-Oppenheimer approximation to describe the interacting quark-meson system, one can derive the effective equation of motion for the nucleon (or baryon), as well as the self-consistent equations for the meson mean fields.

  17. Nonrelativistic hyperfine splitting in muonic helium by adiabatic perturbation theory

    International Nuclear Information System (INIS)

    Drachman, R.J.

    1980-01-01

    Huang and Hughes have recently discussed the hyperfine splitting Δν of muonic helium (α ++ μ - e - ) using a variational approach. In this paper, the Born-Oppenheimer approximation is used to simplify the evaluation of Δν in the nonrelativistic limit. The first-order perturbed wave function of the electron is obtained in closed form by slightly modifying the method used by Dalgarno and Lynn. The result Δν=4450 MHz, is quite close to the published result of Huang and Hughes 4455.2 +- 1 MHz, which required a very large Hylleraas expansion as well as considerable extrapolation

  18. Mass-reduced quantum numbers: application to the isotopic lithium hydrides (X1B+)

    International Nuclear Information System (INIS)

    Li, K.C.; Stwalley, W.C.

    1977-01-01

    The massed-reduced quantum number (MRQN) method of combining isotopic data is applied to the lithium hydride X 1 Σ + ground state. The ΔG(eta) = μ/sup 1 / 2 / ΔG(v), B(eta) = μB(v) and D(eta) = μ 2 D(v) isotopically-combined functions are obtained. An isotopically-combined Rydberg-Klein Rees (ICRKR) potential is constructed using the G(eta) and B(eta) functions. Evidence for breakdown of the Born-Oppenheimer approximation is presented and examined. The Dunham, Simons-Parr-Finlan, and Thakkar methods of potential expansion are also applied to lithium hydride and compared to the RKR Potential

  19. Static and dynamic deformations of actinide nuclei

    International Nuclear Information System (INIS)

    Rozmej, P.

    1985-09-01

    The zero-point quadrupole-hexadecapole vibrations have been taken into account to calculate dynamical deformations for even-even actinide nuclei. The collective and intrinsic motions are separated according to the Born-Oppenheimer approximation. The collective Hamiltonian is constructed using the macroscopic-microscopic method in the potential energy part and the cranking model in the kinetic energy part. The BCS theory with a modified oscillator potential is applied to describe the intrinsic motion of nucleons. A new set of Nilsson potential parameters, which produces a much better description of the properties of light actinide nuclei, has also been found. (orig.)

  20. The role of meson dynamics in nuclear matter saturation

    International Nuclear Information System (INIS)

    Goncalves, E.

    1988-01-01

    The problem of the saturation of nuclea matter in the non-relativistic limit of the model proposed by J.D. Walecka is studied. In the original context nuclear matter saturation is obtained as a direct consequence of relativistic effects and both scalar and vector mesons are treated statically. In the present work we investigate the effect of the meson dynamics for the saturation using a Born-Oppenheimer approximation for the ground state. An upper limit for the saturation curve of nuclear matter and are able to decide now essential is the relativistic treatment of the nucleons for this problem, is obtained. (author) [pt

  1. The form of electron-atom excitation amplitudes at high momentum transfers in the Faddeev-Watson approximation

    International Nuclear Information System (INIS)

    Catalan, G.; Roberts, M.J.

    1979-01-01

    A form of the off-shell Coulomb T matrix, which has a well defined on-shell limit, is used in the Faddeev-Watson multiple-scattering expansion for a direct three-body collision process. Using the excitation of atomic hydrogen by electron impact as an example, approximations to the second-order terms, which are valid for high momentum transfers of the incident electron, are derived. It is shown how the resulting asymptotic behaviour of the second-order Faddeev-Watson approximation is related to the high momentum transfer limit of the second Born approximation. The results are generalised to the excitation of more complex atoms. The asymptotic forms of the Faddeev-Watson and Born approximations are compared with other theories and with measurements of differential cross sections and angular correlation parameters for the excitation of H(2p) and He(2 1 P). The results indicate that the Faddeev-Watson approximation converges more rapidly at high momentum transfers than does the Born approximation. (author)

  2. Towards violation of Born's rule: description of a simple experiment

    International Nuclear Information System (INIS)

    Khrennikov, Andrei

    2011-01-01

    Recently a new model with hidden variables of the wave type was elaborated, so called prequantum classical statistical field theory (PCSFT). Roughly speaking PCSFT is a classical signal theory applied to a special class of signals - 'quantum systems'. PCSFT reproduces successfully all probabilistic predictions of QM, including correlations for entangled systems. This model peacefully coexists with all known no-go theorems, including Bell's theorem. In our approach QM is an approximate model. All probabilistic predictions of QM are only (quite good) approximations of 'real physical averages'. The latter are averages with respect to fluctuations of prequantum fields. In particular, Born's rule is only an approximate rule. More precise experiments should demonstrate its violation. We present a simple experiment which has to produce statistical data violating Born's rule. Since the PCSFT-presentation of this experiment may be difficult for experimenters, we reformulate consequences of PCSFT in terms of the conventional wave function. In general, deviation from Born's rule is rather small. We found an experiment amplifying this deviation. We start with a toy example. Then we present a more realistic example based on Gaussian states with very small dispersion.

  3. Generalized Born Models of Macromolecular Solvation Effects

    Science.gov (United States)

    Bashford, Donald; Case, David A.

    2000-10-01

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

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

    Science.gov (United States)

    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.

  5. Monte Carlo wave packet approach to dissociative multiple ionization in diatomic molecules

    DEFF Research Database (Denmark)

    Leth, Henriette Astrup; Madsen, Lars Bojer; Mølmer, Klaus

    2010-01-01

    A detailed description of the Monte Carlo wave packet technique applied to dissociative multiple ionization of diatomic molecules in short intense laser pulses is presented. The Monte Carlo wave packet technique relies on the Born-Oppenheimer separation of electronic and nuclear dynamics...... and provides a consistent theoretical framework for treating simultaneously both ionization and dissociation. By simulating the detection of continuum electrons and collapsing the system onto either the neutral, singly ionized or doubly ionized states in every time step the nuclear dynamics can be solved....... The computational effort is restricted and the model is applicable to any molecular system where electronic Born-Oppenheimer curves, dipole moment functions, and ionization rates as a function of nuclear coordinates can be determined....

  6. Breakthrough Design and Implementation of Many-Body Theories. Final Scientific/Technical Report

    International Nuclear Information System (INIS)

    Hirata, So

    2012-01-01

    This report discusses the following highlights of the project: (1) grid-based Hartree-Fock equation solver; (2) explicitly correlated coupled-cluster and perturbation methods; (3) anharmonic vibrational frequencies and vibrationally averaged NMR and structural parameters of FHF; (4) anharmonic vibrational frequencies and vibrationally averaged structures of hydrocarbon combustion species; (5) anharmonic vibrational analysis of the guanine-cytosine base pair; (6) the nature of the Born-Oppenheimer approximation; (7) Polymers and solids Brillouin-zone downsampling - the modulo MP2 method; (8) explicitly correlated MP2 for extended systems; (9) fast correlated method for molecular crystals - solid formic acid; and (10) fast correlated method for molecular crystals - solid hydrogen fluoride.

  7. Final Scientific/Technical Report: Breakthrough Design and Implementation of Many-Body Theories for Electron Correlation

    Energy Technology Data Exchange (ETDEWEB)

    So Hirata

    2012-01-03

    This report discusses the following highlights of the project: (1) grid-based Hartree-Fock equation solver; (2) explicitly correlated coupled-cluster and perturbation methods; (3) anharmonic vibrational frequencies and vibrationally averaged NMR and structural parameters of FHF; (4) anharmonic vibrational frequencies and vibrationally averaged structures of hydrocarbon combustion species; (5) anharmonic vibrational analysis of the guanine-cytosine base pair; (6) the nature of the Born-Oppenheimer approximation; (7) Polymers and solids Brillouin-zone downsampling - the modulo MP2 method; (8) explicitly correlated MP2 for extended systems; (9) fast correlated method for molecular crystals - solid formic acid; and (10) fast correlated method for molecular crystals - solid hydrogen fluoride.

  8. Genetic Characterization of the Tick-Borne Orbiviruses

    Directory of Open Access Journals (Sweden)

    Manjunatha N. Belaganahalli

    2015-04-01

    Full Text Available 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.

  9. Ground state of a hydrogen ion molecule immersed in an inhomogeneous electron gas

    International Nuclear Information System (INIS)

    Diaz-Valdes, J.; Gutierrez, F.A.; Matamala, A.R.; Denton, C.D.; Vargas, P.; Valdes, J.E.

    2007-01-01

    In this work we have calculated the ground state energy of the hydrogen molecule, H 2 + , immersed in the highly inhomogeneous electron gas around a metallic surface within the local density approximation. The molecule is perturbed by the electron density of a crystalline surface of Au with the internuclear axis parallel to the surface. The surface spatial electron density is calculated through a linearized band structure method (LMTO-DFT). The ground state of the molecule-ion was calculated using the Born-Oppenheimer approximation for a fixed-ion while the screening effects of the inhomogeneous electron gas are depicted by a Thomas-Fermi like electrostatic potential. We found that within our model the molecular ion dissociates at the critical distance of 2.35a.u. from the first atomic layer of the solid

  10. Bethe, Oppenheimer, Teller and the Fermi Award: Norris Bradbury Speaks

    Energy Technology Data Exchange (ETDEWEB)

    Meade, Roger Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-04-28

    In 1956 the Enrico Fermi Presidential Award was established to recognize scientists, engineers, and science policymakers who gave unstintingly over their careers to advance energy science and technology. The first recipient was John von Neumann. .1 Among those scientists who were thought eligible for the award were Hans Bethe, J. Robert Oppenheimer, and Edward Teller. In 1959 Norris Bradbury was asked to comment on the relative merits of each these three men, whom he knew well from their affiliation with Los Alamos. Below is a reproduction of the letter Bradbury sent to Dr. Warren C. Johnson of the AEC’s General Advisory Committee(GAC) containing his evaluation of each man. The letter might surprise those not accustomed to Bradbury’s modus operandi of providing very detailed and forthright answers to the AEC. The letter, itself, was found in cache of old microfilm. Whether because of the age of the microfilm or the quality of the filming process, portions of the letter are not legible. Where empty brackets appear, the word or words could not be read or deduced. Words appearing in brackets are guesses that appear, from the image, to be what was written. These guesses, of course, are just that – guesses.

  11. Infrared diode laser spectroscopy of lithium hydride

    International Nuclear Information System (INIS)

    Yamada, C.; Hirota, E.

    1988-01-01

    The fundamental and hot bands of the vibration--rotation transitions of 6 LiH, 7 LiH, 6 LiD, and 7 LiD were observed by infrared diode laser spectroscopy at Doppler-limited resolution. Lithium hydride molecules were produced by the reaction of the Li vapor with hydrogen at elevated temperatures. Some 40 transitions were observed and, after combined with submillimeter-wave spectra reported by G. M. Plummer et al. [J. Chem. Phys. 81, 4893 (1984)], were analyzed to yield Dunham-type constants with accuracies more than an order of magnitude higher than those published in the literature. It was clearly demonstrated that the Born--Oppenheimer approximation did not hold, and some parameters representing the breakdown were evaluated. The Born--Oppenheimer internuclear distance r/sup BO//sub e/ was derived to be 1.594 914 26 (59) A, where a new value of Planck's constant recommended by CODATA was employed. The relative intensity of absorption lines was measured to determine the ratio of the permanent dipole moment to its first derivative with respect to the internuclear distance: μ/sub e/ [(partialμpartialr)/sub e/ r/sub e/ ] = 1.743(86). The pressure broadening parameter Δν/sub p/ P was determined to be 6.40 (22) MHzTorr by measuring the linewidth dependence on the pressure of hydrogen, which was about four times larger than the value for the dipole--quadrupole interaction estimated by Kiefer and Bushkovitch's theory

  12. Seismic Imaging and Velocity Analysis Using a Pseudo Inverse to the Extended Born Approximation

    KAUST Repository

    Alali, Abdullah A.

    2018-05-01

    Prestack depth migration requires an accurate kinematic velocity model to image the subsurface correctly. Wave equation migration velocity analysis techniques aim to update the background velocity model by minimizing image residuals to achieve the correct model. The most commonly used technique is differential semblance optimization (DSO), which depends on applying an image extension and penalizing the energy in the non-physical extension. However, studies show that the conventional DSO gradient is contaminated with artifact noise and unwanted oscillations which might lead to local minima. To deal with this issue and improve the stability of DSO, recent studies proposed to use an inversion formula rather than migration to obtain the image. Migration is defined as the adjoint of Born modeling. Since the inversion is complicated and expensive, a pseudo inverse is used instead. A pseudo inverse formula has been developed recently for the horizontal space shift extended Born. This formula preserves the true amplitude and reduces the artifact noise even when an incorrect velocity is used. Although the theory for such an inverse is well developed, it has only been derived and tested on laterally homogeneous models. This is because the formula contains a derivative of the image with respect to a vertical extension evaluated at zero offset. Implementing the vertical extension is computationally expensive, which means this derivative needs to be computed without applying the additional extension. For laterally invariant models, the inverse is simplified and this derivative is eliminated. I implement the full asymptotic inverse to the extended Born to account for laterally heterogeneity. I compute the derivative of the image with respect to a vertical extension without performing any additional shift. This is accomplished by applying the derivative to the imaging condition and utilizing the chain rule. The fact that this derivative is evaluated at zero offset vertical

  13. Dilepton spectrum from quark-gluon plasma in second Born approximation

    International Nuclear Information System (INIS)

    Makhlin, A.N.

    1989-01-01

    The real time temperature Keldysh technique has been used to calculate the rate of dilepton emission from quark-gluon plasma in the first order with respect to strong coupling constant. This approximation us shown to be inconsistent. The radiative corrections turned to be of the same order as the contribution of real processes with gluons. Nevertheless the general properties inherent in dilepton emission from continuous media can be verified by measuring the lepton distribution inside the dilepton. 11 refs.; 2 figs

  14. Atomic lattice excitons: from condensates to crystals

    International Nuclear Information System (INIS)

    Kantian, A; Daley, A J; Toermae, P; Zoller, P

    2007-01-01

    We discuss atomic lattice excitons (ALEs), bound particle-hole pairs formed by fermionic atoms in two bands of an optical lattice. Such a system provides a clean set-up, with tunable masses and interactions, to study fundamental properties of excitons including exciton condensation. We also find that for a large effective mass ratio between particles and holes, effective long-range interactions can mediate the formation of an exciton crystal, for which superfluidity is suppressed. Using a combination of mean-field treatments, bosonized theory based on a Born-Oppenheimer approximation, and one-dimensional (1D) numerical computation, we discuss the properties of ALEs under varying conditions, and discuss in particular their preparation and measurement

  15. Heavy enzymes--experimental and computational insights in enzyme dynamics.

    Science.gov (United States)

    Swiderek, Katarzyna; Ruiz-Pernía, J Javier; Moliner, Vicent; Tuñón, Iñaki

    2014-08-01

    The role of protein motions in the chemical step of enzyme-catalyzed reactions is the subject of an open debate in the scientific literature. The systematic use of isotopically substituted enzymes has been revealed as a useful tool to quantify the role of these motions. According to the Born-Oppenheimer approximation, changing the mass of the protein does not change the forces acting on the system but alters the frequencies of the protein motions, which in turn can affect the rate constant. Experimental and theoretical studies carried out in this field are presented in this article and discussed in the framework of Transition State Theory. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Tetraquark resonances computed with static lattice QCD potentials and scattering theory

    Directory of Open Access Journals (Sweden)

    Bicudo Pedro

    2018-01-01

    Full Text Available We study tetraquark resonances with lattice QCD potentials computed for two static quarks and two dynamical quarks, the Born-Oppenheimer approximation and the emergent wave method of scattering theory. As a proof of concept we focus on systems with isospin I = 0, but consider different relative angular momenta l of the heavy b quarks. We compute the phase shifts and search for S and T matrix poles in the second Riemann sheet. We predict a new tetraquark resonance for l = 1, decaying into two B mesons, with quantum numbers I(JP = 0(1−, mass m=10576−4+4 MeV and decay width Γ=112−103+90 MeV.

  17. Symmetry Breakdown in Ground State Dissociation of HD+

    International Nuclear Information System (INIS)

    Ben-Itzhak, I.; Wells, E.; Carnes, K. D.; Krishnamurthi, Vidhya; Weaver, O. L.; Esry, B. D.

    2000-01-01

    Experimental studies of the dissociation of the electronic ground state of HD + following ionization of HD by fast proton impact indicate that the H + +D 1s dissociation channel is more likely than the H1s+D + dissociation channel by about 7% . This isotopic symmetry breakdown is due to the finite nuclear mass correction to the Born-Oppenheimer approximation which makes the 1sσ state 3.7 meV lower than the 2pσ state at the dissociation limit. The measured fractions of the two dissociation channels are in agreement with coupled-channels calculations of 1sσ to 2pσ transitions. (c) 2000 The American Physical Society

  18. Observation of the Rotational Spectra of 4HeH+, 4HeD+, 3HeH+, and 3HeD+

    International Nuclear Information System (INIS)

    Matsushima, F.; Oka, T.; Takagi, K.

    1997-01-01

    Low J rotational transitions of 4 HeH + , 4 HeD + , 3 HeH + , and 3 HeD + were observed in the 2 endash 5THz region with a high-precision far-infrared spectrometer. Dunham coefficients Y kl and isotopically independent parameters U kl , Δ He kl , and Δ H kl were determined. In particular, Δ parameters with k=0 and l=1,2 were determined with unprecedented accuracy, and provide important information for breakdown of the Born-Oppenheimer approximation. The lowest J=1 left-arrow 0 transition of 4 HeH + observed at 2010.1839(2)GHz will be an important future probe for detecting this species in space. copyright 1997 The American Physical Society

  19. Atomic lattice excitons: from condensates to crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kantian, A [Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Daley, A J [Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Toermae, P [Nanoscience Center, Department of Physics, University of Jyvaeskylae, PO Box 35, FIN-40014 (Finland); Zoller, P [Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck (Austria)

    2007-11-15

    We discuss atomic lattice excitons (ALEs), bound particle-hole pairs formed by fermionic atoms in two bands of an optical lattice. Such a system provides a clean set-up, with tunable masses and interactions, to study fundamental properties of excitons including exciton condensation. We also find that for a large effective mass ratio between particles and holes, effective long-range interactions can mediate the formation of an exciton crystal, for which superfluidity is suppressed. Using a combination of mean-field treatments, bosonized theory based on a Born-Oppenheimer approximation, and one-dimensional (1D) numerical computation, we discuss the properties of ALEs under varying conditions, and discuss in particular their preparation and measurement.

  20. Non-Born-Oppenheimer trajectories with self-consistent decay of mixing

    International Nuclear Information System (INIS)

    Zhu Chaoyuan; Jasper, Ahren W.; Truhlar, Donald G.

    2004-01-01

    A semiclassical trajectory method, called the self-consistent decay of mixing (SCDM) method, is presented for the treatment of electronically nonadiabatic dynamics. The SCDM method is a modification of the semiclassical Ehrenfest (SE) method (also called the semiclassical time-dependent self-consistent-field method) that solves the problem of unphysical mixed final states by including decay-of-mixing terms in the equations for the evolution of the electronic state populations. These terms generate a force, called the decoherent force (or dephasing force), that drives the electronic component of each trajectory toward a pure state. Results for several mixed quantum-classical methods, in particular the SCDM, SE, and natural-decay-of-mixing methods and several trajectory surface hopping methods, are compared to the results of accurate quantum mechanical calculations for 12 cases involving five different fully dimensional triatomic model systems. The SCDM method is found to be the most accurate of the methods tested. The method should be useful for the simulation of photochemical reactions

  1. Muonic molecular ions p p μ and p d μ driven by superintense VUV laser pulses: Postexcitation muonic and nuclear oscillations and high-order harmonic generation

    Science.gov (United States)

    Paramonov, Guennaddi K.; Saalfrank, Peter

    2018-05-01

    The non-Born-Oppenheimer quantum dynamics of p p μ and p d μ molecular ions excited by ultrashort, superintense VUV laser pulses polarized along the molecular axis (z ) is studied by the numerical solution of the time-dependent Schrödinger equation within a three-dimensional (3D) model, including the internuclear distance R and muon coordinates z and ρ , a transversal degree of freedom. It is shown that in both p p μ and p d μ , muons approximately follow the applied laser field out of phase. After the end of the laser pulse, expectation values , , and demonstrate "post-laser-pulse" oscillations in both p p μ and p d μ . In the case of p d μ , the post-laser-pulse oscillations of and appear as shaped "echo pulses." Power spectra, which are related to high-order harmonic generation (HHG), generated due to muonic and nuclear motion are calculated in the acceleration form. For p d μ it is found that there exists a unique characteristic frequency ωoscp d μ representing both frequencies of post-laser-pulse muonic oscillations and the frequency of nuclear vibrations, which manifest themselves by very sharp maxima in the corresponding power spectra of p d μ . The homonuclear p p μ ion does not possess such a unique characteristic frequency. The "exact" dynamics and power, and HHG spectra of the 3D model are compared with a Born-Oppenheimer, fixed-nuclei model featuring interesting differences: postpulse oscillations are absent and HHG spectra are affected indirectly or directly by nuclear motion.

  2. Convergence of the Distorted Wave Born series

    International Nuclear Information System (INIS)

    MacMillan, D.S.

    1981-01-01

    The aim of this thesis is to begin to understand the idea of reaction mechanisms in nonrelativistic scattering systems. If we have a complete reaction theory of a particular scattering system, then we claim that the theory itself must contain information about important reaction mechanisms in the system. This information can be used to decide what reaction mechanisms should be included in an approximate calculation. To investigate this claim, we studied several solvable models. The primary concept employed in studying our models is the convergence of the multistep series generated by iterating the corresponding scattering integral equation. We known that the eigenvalues of the kernel of the Lippmann-Schwinger equation for potential scattering determine the rate of convergence of the Born series. The Born series will converge only if these eigenvalues all life within the unit circle. We extend these results to a study of the distorted wave Born series for inelastic scattering. The convergence criterion tells us when approximations are valid. We learn how the convergence of the distorted wave series depends upon energy, coupling constants, angular momentum, and angular momentum transfer. In one of our models, we look at several possible distorting potentials to see which one gives the best convergence. We have also applied our results to several actual DWBA or coupled channel calculations in the literature. In addition to the study of models of two-body scattering systems, we have considered the case of rearrangement scattering. We have discussed the formulation of (N greater than or equal to 3)-body distorted wave equations in which the interior dynamics have been redistributed by introducing compact N-body distortion potentials

  3. Extended particle model with quark confinement and charmonium spectroscopy

    International Nuclear Information System (INIS)

    Hasenfratz, Peter; Kuti, Julius; Szalay, A.S.

    Extended particle like vector gluon bubbles /bags/ are introduced which are stabilized against free expansion by a surface tension of volume tension. Since quraks are coupled to the gluon field, they are confined to the inside of the gluon bag without any further mechanism. Only color singlet gluon bags are allowed. Nonlinear boundary conditions are not imposed on the quark field in the model. A massless abelian gauge confined by a surface tension is first considered; in a four-dimensional relativistic picture the surface of the gauge field bubble appears as a tube with a three dimensional surface. As a first application, the model is used to study bound states of heavy charmed quarks (charmonium). Similar to the Born-Oppenheimer approximation in molecular physics, heavy charmed quarks are treated as nonrelativistic in their motion whereas the gluon bag and light quarks (u,d,s) are treated in an adiabatic approximation

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

    Science.gov (United States)

    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.

  5. A differential equation for the Generalized Born radii.

    Science.gov (United States)

    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.

  6. Spectroscopic study of uracil, 1-methyluracil and 1-methyl-4-thiouracil: Hydrogen bond interactions in crystals and ab-initio molecular dynamics

    Science.gov (United States)

    Brela, Mateusz Z.; Boczar, Marek; Malec, Leszek M.; Wójcik, Marek J.; Nakajima, Takahito

    2018-05-01

    Hydrogen bond networks in uracil, 1-methyluracil and 1-methyl-4-thiouracil were studied by ab initio molecular dynamics as well as analysis of the orbital interactions. The power spectra calculated by ab initio molecular dynamics for atoms involved in hydrogen bonds were analyzed. We calculated spectra by using anharmonic approximation based on the autocorrelation function of the atom positions obtained from the Born-Oppenheimer simulations. Our results show the differences between hydrogen bond networks in uracil and its methylated derivatives. The studied methylated derivatives, 1-methyluracil as well as 1-methyl-4-thiouracil, form dimeric structures in the crystal phase, while uracil does not form that kind of structures. The presence of sulfur atom instead oxygen atom reflects weakness of the hydrogen bonds that build dimers.

  7. Matrix elements of N-particle explicitly correlated Gaussian basis functions with complex exponential parameters.

    Science.gov (United States)

    Bubin, Sergiy; Adamowicz, Ludwik

    2006-06-14

    In this work we present analytical expressions for Hamiltonian matrix elements with spherically symmetric, explicitly correlated Gaussian basis functions with complex exponential parameters for an arbitrary number of particles. The expressions are derived using the formalism of matrix differential calculus. In addition, we present expressions for the energy gradient that includes derivatives of the Hamiltonian integrals with respect to the exponential parameters. The gradient is used in the variational optimization of the parameters. All the expressions are presented in the matrix form suitable for both numerical implementation and theoretical analysis. The energy and gradient formulas have been programmed and used to calculate ground and excited states of the He atom using an approach that does not involve the Born-Oppenheimer approximation.

  8. Matrix elements of N-particle explicitly correlated Gaussian basis functions with complex exponential parameters

    Science.gov (United States)

    Bubin, Sergiy; Adamowicz, Ludwik

    2006-06-01

    In this work we present analytical expressions for Hamiltonian matrix elements with spherically symmetric, explicitly correlated Gaussian basis functions with complex exponential parameters for an arbitrary number of particles. The expressions are derived using the formalism of matrix differential calculus. In addition, we present expressions for the energy gradient that includes derivatives of the Hamiltonian integrals with respect to the exponential parameters. The gradient is used in the variational optimization of the parameters. All the expressions are presented in the matrix form suitable for both numerical implementation and theoretical analysis. The energy and gradient formulas have been programed and used to calculate ground and excited states of the He atom using an approach that does not involve the Born-Oppenheimer approximation.

  9. Scalar geons in Born-Infeld gravity

    Energy Technology Data Exchange (ETDEWEB)

    Afonso, V.I. [Unidade Acadêmica de Física, Universidade Federal de Campina Grande, 58109-970 Campina Grande, PB (Brazil); Olmo, Gonzalo J. [Departamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia—CSIC, Universidad de Valencia, Burjassot-46100, Valencia (Spain); Rubiera-Garcia, D., E-mail: viafonso@df.ufcg.edu.br, E-mail: gonzalo.olmo@uv.es, E-mail: drgarcia@fc.ul.pt [Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências da Universidade de Lisboa, Edifício C8, Campo Grande, P-1749-016 Lisbon (Portugal)

    2017-08-01

    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 M , 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.

  10. First principles molecular dynamics without self-consistent field optimization

    International Nuclear Information System (INIS)

    Souvatzis, Petros; Niklasson, Anders M. N.

    2014-01-01

    We present a first principles molecular dynamics approach that is based on time-reversible extended Lagrangian Born-Oppenheimer molecular dynamics [A. M. N. Niklasson, Phys. Rev. Lett. 100, 123004 (2008)] in the limit of vanishing self-consistent field optimization. The optimization-free dynamics keeps the computational cost to a minimum and typically provides molecular trajectories that closely follow the exact Born-Oppenheimer potential energy surface. Only one single diagonalization and Hamiltonian (or Fockian) construction are required in each integration time step. The proposed dynamics is derived for a general free-energy potential surface valid at finite electronic temperatures within hybrid density functional theory. Even in the event of irregular functional behavior that may cause a dynamical instability, the optimization-free limit represents a natural starting guess for force calculations that may require a more elaborate iterative electronic ground state optimization. Our optimization-free dynamics thus represents a flexible theoretical framework for a broad and general class of ab initio molecular dynamics simulations

  11. The differential effect of foreign-born status on low birth weight by race/ethnicity and education.

    Science.gov (United States)

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

    2005-01-01

    This article investigates whether foreign-born status confers a protective effect against low birth weight (LBW) and whether this protective effect varies across racial/ethnic groups and by socioeconomic status (ie, education) within various racial/ethnic groups. Logistic regression analyses of the Detail Natality Data, 1998 (n = 2,436,890), were used to examine differentials in LBW by nativity across racial/ethnic groups and by education level. Although foreign-born status does not protect against LBW among white women (95% confidence interval [CI]: 0.96, 1.03) and it increases the risk among Asian women by 24% (95% CI: 1.13, 1.36), it reduces the risk by approximately 25% among black women (95% CI: 0.72, 0.78) and by approximately 19% among Hispanic women (95% CI: 0.78, 0.84). By educational attainment, for whites, blacks, and Hispanics the protective effect of foreign-born status is stronger among women with low education (ie, 0-11 years) than among women with more education. The educational gradient in LBW is less pronounced among foreign-born white, black, and Hispanic women than among their US-born counterparts. Foreign-born status is associated with LBW. The direction and strength of this association varies across racial/ethnic groups, and within those groups it varies by educational level. Future research may test hypotheses regarding the mechanisms underlying these variations in LBW, including health selection of immigrants, cultural factors, social support, and social environment.

  12. A variational approach to operator and matrix Pade approximation. Applications to potential scattering and field theory

    International Nuclear Information System (INIS)

    Mery, P.

    1977-01-01

    The operator and matrix Pade approximation are defined. The fact that these approximants can be derived from the Schwinger variational principle is emphasized. In potential theory, using this variational aspect it is shown that the matrix Pade approximation allow to reproduce the exact solution of the Lippman-Schwinger equation with any required accuracy taking only into account the knowledge of the first two coefficients in the Born expansion. The deep analytic structure of this variational matrix Pade approximation (hyper Pade approximation) is discussed

  13. Program POD; A computer code to calculate nuclear elastic scattering cross sections with the optical model and neutron inelastic scattering cross sections by the distorted-wave born approximation

    International Nuclear Information System (INIS)

    Ichihara, Akira; Kunieda, Satoshi; Chiba, Satoshi; Iwamoto, Osamu; Shibata, Keiichi; Nakagawa, Tsuneo; Fukahori, Tokio; Katakura, Jun-ichi

    2005-07-01

    The computer code, POD, was developed to calculate angle-differential cross sections and analyzing powers for shape-elastic scattering for collisions of neutron or light ions with target nucleus. The cross sections are computed with the optical model. Angle-differential cross sections for neutron inelastic scattering can also be calculated with the distorted-wave Born approximation. The optical model potential parameters are the most essential inputs for those model computations. In this program, the cross sections and analyzing powers are obtained by using the existing local or global parameters. The parameters can also be inputted by users. In this report, the theoretical formulas, the computational methods, and the input parameters are explained. The sample inputs and outputs are also presented. (author)

  14. Approximate Coulomb effects in the three-body scattering problem

    International Nuclear Information System (INIS)

    Haftel, M.I.; Zankel, H.

    1981-01-01

    From the momentum space Faddeev equations we derive approximate expressions which describe the Coulomb-nuclear interference in the three-body elastic scattering, rearrangement, and breakup problems and apply the formalism to p-d elastic scattering. The approximations treat the Coulomb interference as mainly a two-body effect, but we allow for the charge distribution of the deuteron in the p-d calculations. Real and imaginary parts of the Coulomb correction to the elastic scattering phase shifts are described in terms of on-shell quantities only. In the case of pure Coulomb breakup we recover the distorted-wave Born approximation result. Comparing the derived approximation with the full Faddeev p-d elastic scattering calculation, which includes the Coulomb force, we obtain good qualitative agreement in S and P waves, but disagreement in repulsive higher partial waves. The on-shell approximation investigated is found to be superior to other current approximations. The calculated differential cross sections at 10 MeV raise the question of whether there is a significant Coulomb-nuclear interference at backward angles

  15. From Becquerel to Oppenheimer-Nuclear energy story. De Becquerel a Oppenheimer: histoire de l'energie nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Mataix, M

    1994-02-01

    To tell the nuclear energy story is to tell the story of a science, which in less than a century was born in a small laboratory to reach a large industry level. This science upset the principles that physics established since the time origin and then left a mark the men story course and their way of life while arousing enthusiasm or rejection reactions that no human invention incited until then. Such a topic is critical to deal, the author does with much talent. He describes us these epic participants and the bonds that they kept up. He places their thoughts and works advance in the historical, sometimes turbulent context which was that of the century beginning. We will discover the personality of these scientists whose name is often recalled by a physical law or a measure unit, but who were first of all women and men applied to improve the human beings welfare while studying thoroughly the atom mysteries.

  16. Vibrationally resolved photoelectron spectra of lower diamondoids: A time-dependent approach

    Science.gov (United States)

    Xiong, Tao; Włodarczyk, Radosław; Gallandi, Lukas; Körzdörfer, Thomas; Saalfrank, Peter

    2018-01-01

    Vibrationally resolved lowest-energy bands of the photoelectron spectra (PES) of adamantane, diamantane, and urotropine were simulated by a time-dependent correlation function approach within the harmonic approximation. Geometries and normal modes for neutral and cationic molecules were obtained from B3LYP hybrid density functional theory (DFT). It is shown that the simulated spectra reproduce the experimentally observed vibrational finestructure (or its absence) quite well. Origins of the finestructure are discussed and related to recurrences of autocorrelation functions and dominant vibrations. Remaining quantitative and qualitative errors of the DFT-derived PES spectra refer to (i) an overall redshift by ˜0.5 eV and (ii) the absence of satellites in the high-energy region of the spectra. The former error is shown to be due to the neglect of many-body corrections to ordinary Kohn-Sham methods, while the latter has been argued to be due to electron-nuclear couplings beyond the Born-Oppenheimer approximation [Gali et al., Nat. Commun. 7, 11327 (2016)].

  17. (4)He Thermophysical Properties: New Ab Initio Calculations.

    Science.gov (United States)

    Hurly, John J; Mehl, James B

    2007-01-01

    Since 2000, atomic physicists have reduced the uncertainty of the helium-helium "ab initio" potential; for example, from approximately 0.6 % to 0.1 % at 4 bohr, and from 0.8 % to 0.1 % at 5.6 bohr. These results led us to: (1) construct a new inter-atomic potential ϕ 07, (2) recalculate values of the second virial coefficient, the viscosity, and the thermal conductivity of (4)He from 1 K to 10,000 K, and (3), analyze the uncertainties of the thermophysical properties that propagate from the uncertainty of ϕ 07 and from the Born-Oppenheimer approximation of the electron-nucleon quantum mechanical system. We correct minor errors in a previous publication [J. J. Hurly and M. R. Moldover, J. Res. Nat. Inst. Standards Technol. 105, 667 (2000)] and compare our results with selected data published after 2000. The ab initio results tabulated here can serve as standards for the measurement of thermophysical properties.

  18. 4He Thermophysical Properties: New Ab Initio Calculations

    Science.gov (United States)

    Hurly, John J.; Mehl, James B.

    2007-01-01

    Since 2000, atomic physicists have reduced the uncertainty of the helium-helium “ab initio” potential; for example, from approximately 0.6 % to 0.1 % at 4 bohr, and from 0.8 % to 0.1 % at 5.6 bohr. These results led us to: (1) construct a new inter-atomic potential ϕ07, (2) recalculate values of the second virial coefficient, the viscosity, and the thermal conductivity of 4He from 1 K to 10,000 K, and (3), analyze the uncertainties of the thermophysical properties that propagate from the uncertainty of ϕ07 and from the Born-Oppenheimer approximation of the electron-nucleon quantum mechanical system. We correct minor errors in a previous publication [J. J. Hurly and M. R. Moldover, J. Res. Nat. Inst. Standards Technol. 105, 667 (2000)] and compare our results with selected data published after 2000. The ab initio results tabulated here can serve as standards for the measurement of thermophysical properties. PMID:27110456

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

    Science.gov (United States)

    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.

  20. Continuum orbital approximations in weak-coupling theories for inelastic electron scattering

    International Nuclear Information System (INIS)

    Peek, J.M.; Mann, J.B.

    1977-01-01

    Two approximations, motivated by heavy-particle scattering theory, are tested for weak-coupling electron-atom (ion) inelastic scattering theory. They consist of replacing the one-electron scattering orbitals by their Langer uniform approximations and the use of an average trajectory approximation which entirely avoids the necessity for generating continuum orbitals. Numerical tests for a dipole-allowed and a dipole-forbidden event, based on Coulomb-Born theory with exchange neglected, reveal the error trends. It is concluded that the uniform approximation gives a satisfactory prediction for traditional weak-coupling theories while the average approximation should be limited to collision energies exceeding at least twice the threshold energy. The accuracy for both approximations is higher for positive ions than for neutral targets. Partial-wave collision-strength data indicate that greater care should be exercised in using these approximations to predict quantities differential in the scattering angle. An application to the 2s 2 S-2p 2 P transition in Ne VIII is presented

  1. Solution of the Chew-Low equations in the quadratic approximation

    International Nuclear Information System (INIS)

    Gerdt, V.P.; Zharkov, A.Yu.

    1982-01-01

    Within the framework of the iteration scheme for constructing the general solution of the Chew-Low equations as suggested earlier the second order power contributions are found. In contrast to the linear approximation obtained before the quadratic approximation includes an infinite number of poles on the complex plane of the uniformizing variable w. It is shown that taking into account the second order corrections in the general solution allows us to select the class of solutions possessing the Born pole at w=0. The most cumbersome part of analytical computations has been carried out by computer using the algebraic system REDUCE-2

  2. Impact of cloud-borne aerosol representation on aerosol direct and indirect effects

    Directory of Open Access Journals (Sweden)

    S. J. Ghan

    2006-01-01

    Full Text Available Aerosol particles attached to cloud droplets are much more likely to be removed from the atmosphere and are much less efficient at scattering sunlight than if unattached. Models used to estimate direct and indirect effects of aerosols employ a variety of representations of such cloud-borne particles. Here we use a global aerosol model with a relatively complete treatment of cloud-borne particles to estimate the sensitivity of simulated aerosol, cloud and radiation fields to various approximations to the representation of cloud-borne particles. We find that neglecting transport of cloud-borne particles introduces little error, but that diagnosing cloud-borne particles produces global mean biases of 20% and local errors of up to 40% for aerosol, droplet number, and direct and indirect radiative forcing. Aerosol number, aerosol optical depth and droplet number are significantly underestimated in regions and seasons where and when wet removal is primarily by stratiform rather than convective clouds (polar regions during winter, but direct and indirect effects are less biased because of the limited sunlight there and then. A treatment that predicts the total mass concentration of cloud-borne particles for each mode yields smaller errors and runs 20% faster than the complete treatment. The errors are much smaller than current estimates of uncertainty in direct and indirect effects of aerosols, which suggests that the treatment of cloud-borne aerosol is not a significant source of uncertainty in estimates of direct and indirect effects.

  3. Quantum tunneling in the adiabatic Dicke model

    International Nuclear Information System (INIS)

    Chen Gang; Chen Zidong; Liang Jiuqing

    2007-01-01

    The Dicke model describes N two-level atoms interacting with a single-mode bosonic field and exhibits a second-order phase transition from the normal to the superradiant phase. The energy levels are not degenerate in the normal phase but have degeneracy in the superradiant phase, where quantum tunneling occurs. By means of the Born-Oppenheimer approximation and the instanton method in quantum field theory, the tunneling splitting, inversely proportional to the tunneling rate for the adiabatic Dicke model, in the superradiant phase can be evaluated explicitly. It is shown that the tunneling splitting vanishes as exp(-N) for large N, whereas for small N it disappears as √(N)/exp(N). The dependence of the tunneling splitting on the relevant parameters, especially on the atom-field coupling strength, is also discussed

  4. Advanced software for the calculation of thermochemistry, kinetics, and dynamics

    International Nuclear Information System (INIS)

    Shepard, R; Wagner, A F; Gray, S K

    2006-01-01

    The Born-Oppenheimer separation of the Schrodinger equation allows the electronic and nuclear motions to be solved in three steps. 1) The solution of the electronic wave function at a discrete set of molecular conformations; 2) the fitting of this discrete set of energy values in order to construct an analytical approximation to the potential energy surface (PES) at all molecular conformations; 3) the use of this analytical PES to solve for the nuclear motion using either time-dependent or time-independent formulations to compute molecular energy values, chemical reaction rates, and cumulative reaction probabilities. This project involves the development of technology to address all three of these steps. This report focuses on our recent work on the optimization of nonlinear wave function parameters for the electronic wave functions

  5. Inverse scattering problem for a magnetic field in the Glauber approximation

    International Nuclear Information System (INIS)

    Bogdanov, I.V.

    1985-01-01

    New results in the general theory of scattering are obtained. An inverse problem at fixed energy for an axisymmetric magnetic field is formulated and solved within the frames of the quantum-mechanical Glauber approximation. The solution is found in quadratures in the form of an explicit inversion algorithm reproducing a vector potential by the angular dependence of the scattering amplitude. Extreme transitions from the eikonal inversion method to the classical and Born ones are investigated. Integral and differential equations are derived for the eikonal amplitude that ensure the real value of the vector potential and its energy independence. Magnetoelectric analogies the existence of equivalent axisymmetric electric and magnetic fields scattering charged particles in the same manner both in the Glauber and Born approximation are established. The mentioned analogies permit to simulate ion-potential scattering by potential one that is of interest from the practical viewpoint. Three-dimensional (excentral) eikonal inverse problems for the electric and magnetic fields are discussed. The results of the paper can be used in electron optics

  6. Second-order Born effect in coplanar doubly symmetric (e,2e) collisions for sodium

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yang; Jiao, Liguang [Center for Theoretical Atomic and Molecular Physics, Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080 (China); Zhou, Yajun, E-mail: yajunzhou2003@yahoo.com.cn [Center for Theoretical Atomic and Molecular Physics, Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080 (China)

    2012-06-18

    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 alkali target sodium at excess energies of 6–60 eV. Comparing with the first-order DWBA calculations, the inclusion of second-order Born term in the scattering amplitude improves the degree of agreement with experiments, especially for backward scattering region of TDCS. This indicates the present second-order Born term is capable to give a reasonable correction to DWBA model in studying coplanar symmetric (e,2e) problems in low and intermediate energy range. -- Highlights: ► We consider second-order Born effect in (e,2e) collisions for sodium. ► Our second-order term gives a correct description on the multi scattering process. ► Our second-order DWBA model improves the agreement between theory and experiment.

  7. Estimation of error in using born scaling for collision cross sections involving muonic ions

    International Nuclear Information System (INIS)

    Stodden, C.D.; Monkhorst, H.J.; Szalewicz, K.

    1988-01-01

    A quantitative estimate is obtained for the error involved in using Born scaling to calcuated excitation and ionization cross sections for collisions between muonic ions. The impact parameter version of the Born Approximation is used to calculate cross sections and Coulomb corrections for the 1s→2s excitation of αμ in collisions with d. An error of about 50% is found around the peak of the cross section curve. The error falls to less than 5% for velocities above 2 a.u

  8. Early Recollections of First-Borns.

    Science.gov (United States)

    Fakouri, M. Ebrahim; Hafner, James L.

    1984-01-01

    Compared the early recollections of 50 first-borns and 98 later-borns. The first-borns mentioned significantly more nonfamily members, illness/injury, hospital/doctor's office. Later-borns mentioned significantly more siblings than did first-borns. Findings were discussed in the context of Adler's personality theory. (JAC)

  9. Quark cluster model and confinement

    International Nuclear Information System (INIS)

    Koike, Yuji; Yazaki, Koichi

    2000-01-01

    How confinement of quarks is implemented for multi-hadron systems in the quark cluster model is reviewed. In order to learn the nature of the confining interaction for fermions we first study 1+1 dimensional QED and QCD, in which the gauge field can be eliminated exactly and generates linear interaction of fermions. Then, we compare the two-body potential model, the flip-flop model and the Born-Oppenheimer approach in the strong coupling lattice QCD for the meson-meson system. Having shown how the long-range attraction between hadrons, van der Waals interaction, shows up in the two-body potential model, we discuss two distinct attempts beyond the two-body potential model: one is a many-body potential model, the flip-flop model, and the other is the Born-Oppenheimer approach in the strong coupling lattice QCD. We explain how the emergence of the long-range attraction is avoided in these attempts. Finally, we present the results of the application of the flip-flop model to the baryon-baryon scattering in the quark cluster model. (author)

  10. Patched Skin Bilirubin Assay to Monitor Neonates Born Extremely Preterm Undergoing Phototherapy.

    Science.gov (United States)

    De Luca, Daniele; Dell'Orto, Valentina

    2017-09-01

    To verify the reliability and safety of transcutaneous bilirubin (TcB) measurements in patched skin areas in neonates born extremely preterm under phototherapy. Sixty neonates (bilirubin (TSB), lactate, pH, hemoglobin, and skin temperature were measured within 10 minutes of the TcB assay. Clinicians were blinded to TcB values, and clinical decisions about phototherapy were made with the TSB measurement only. TcB and TSB significantly were correlated (r = 0.84; P bilirubin passage. TcB overestimated TSB, and this may expose infants born preterm to unnecessary phototherapy, although it could spare approximately 65% of TSB assays. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. [Tick-borne diseases].

    Science.gov (United States)

    Tissot Dupont, H; Raoult, D

    1993-05-01

    Due to their worldwide distribution, from hottest to coldest climates, and due to their behaviour, ticks are capable of transmitting numerous human and animal bacterial viral or parasitous diseases. Depending on the disease, they play the role of biological vector or intermediate host. In France, six tick borne diseases are of epidemiologic importance. Q fever (not often tick-borne), Mediterranean Spotted Fever, Lyme disease, Turalemia (human and animal), Babesiosis and Tick-borne Viral Encephalitis.

  12. Vibrational frame transformation for electron-molecule scattering

    International Nuclear Information System (INIS)

    Greene, C.H.; Jungen, C.

    1985-01-01

    The frame-transformation theory of electron interaction with a vibrating diatomic core is extended to allow for energy dependence of its parameters. The Born-Oppenheimer separation of electron and nuclear motion is preserved when the electron penetrates the molecular core. The extended theory reproduces the boomerang-model treatment of vibrational excitation in resonant e-N 2 collisions

  13. Innovative Born Globals

    DEFF Research Database (Denmark)

    Kraus, Sascha; Brem, Alexander; Muench, Miriam

    2017-01-01

    Internationalization is a hot topic in innovation management, whereby the phenomenon of “Born Globals” is still limited to research in the domains of Entrepreneurship and International Management. As business model design plays a key role for Born Globals, we link these two concepts. For this, we...... propose hypotheses about the influence of efficiency-centered and novelty-entered business model design on international firm performance. To test these hypotheses, we performed a quantitative survey with 252 founders of international companies in Germany, Switzerland and Liechtenstein. Additionally, we...... gained further insights through a case study analysis of 11 Born Globals. The results show that business model design matters to international firm performance and the business model design of Born Globals tends to be more efficiency-centered. Based on a multiple case study, we analyzed business models...

  14. Fission fragment mass and total kinetic energy distributions of spontaneously fissioning plutonium isotopes

    Science.gov (United States)

    Pomorski, K.; Nerlo-Pomorska, B.; Bartel, J.; Schmitt, C.

    2018-03-01

    The fission-fragment mass and total kinetic energy (TKE) distributions are evaluated in a quantum mechanical framework using elongation, mass asymmetry, neck degree of freedom as the relevant collective parameters in the Fourier shape parametrization recently developed by us. The potential energy surfaces (PES) are calculated within the macroscopic-microscopic model based on the Lublin-Strasbourg Drop (LSD), the Yukawa-folded (YF) single-particle potential and a monopole pairing force. The PES are presented and analysed in detail for even-even Plutonium isotopes with A = 236-246. They reveal deep asymmetric valleys. The fission-fragment mass and TKE distributions are obtained from the ground state of a collective Hamiltonian computed within the Born-Oppenheimer approximation, in the WKB approach by introducing a neck-dependent fission probability. The calculated mass and total kinetic energy distributions are found in good agreement with the data.

  15. Tunneling Ionization of Diatomic Molecules

    DEFF Research Database (Denmark)

    Svensmark, Jens Søren Sieg

    2016-01-01

    When a molecule is subject to a strong laser field, there is a probability that an electron can escape, even though the electrons are bound by a large potential barrier. This is possible because electrons are quantum mechanical in nature, and they are therefore able to tunnel through potential...... barriers, an ability classical particles do not possess. Tunnelling is a fundamental quantum mechanical process, a process that is distinctly non-classical, so solving this tunnelling problem is not only relevant for molecular physics, but also for quantum theory in general. In this dissertation the theory...... of tunneling ionizaion of molecules is presented and the results of numerical calculations are shown. One perhaps surprising result is, that the frequently used Born-Oppenheimer approximation breaks down for weak fields when describing tunneling ionization. An analytic theory applicable in the weak-field limit...

  16. Adiabatic perturbation theory in quantum dynamics

    CERN Document Server

    Teufel, Stefan

    2003-01-01

    Separation of scales plays a fundamental role in the understanding of the dynamical behaviour of complex systems in physics and other natural sciences. A prominent example is the Born-Oppenheimer approximation in molecular dynamics. This book focuses on a recent approach to adiabatic perturbation theory, which emphasizes the role of effective equations of motion and the separation of the adiabatic limit from the semiclassical limit. A detailed introduction gives an overview of the subject and makes the later chapters accessible also to readers less familiar with the material. Although the general mathematical theory based on pseudodifferential calculus is presented in detail, there is an emphasis on concrete and relevant examples from physics. Applications range from molecular dynamics to the dynamics of electrons in a crystal and from the quantum mechanics of partially confined systems to Dirac particles and nonrelativistic QED.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    OpenAIRE

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

    2009-01-01

    Differential exposure to minority status stressors may help explain differences in United States (US)-born and foreign-born Black women’s birth outcomes. We explored self-reports of racism recorded in a survey of 185 US-born and 114 foreign-born Black pregnant women enrolled in Project Viva, a prospective cohort study of pregnant women in Boston, Massachusetts, USA. Self-reported prevalence of personal racism and group racism was significantly higher among US-born than foreign-born Black preg...

  19. Theoretical study of quantum molecular reaction dynamics and of the effects of intense laser radiation on a diatomic molecule

    International Nuclear Information System (INIS)

    Dardi, P.S.

    1984-11-01

    Within the very broad field of molecular dynamics, we have concentrated on two simple yet important systems. The systems are simple enough so that they are adequately described with a single Born-Oppenheimer potential energy surface and that the dynamics can be calculated accurately. They are important because they give insight into solving more complicated systems. First we discuss H + H 2 reactive scattering. We present an exact formalism for atom-diatom reactive scattering which avoids the problem of finding a coordinate system appropriate for both reactants and products. We present computational results for collinear H + H 2 reactive scattering which agree very well with previous calculations. We also present a coupled channel distorted wave Born approximation for atom-diatom reactive scattering which we show is a first order approximation to our exact formalism. We present coupled channel DWBA results for three dimensional H + H 2 reactive scattering. The second system is an isolated HF molecule in an intense laser field. Using classical trajectories and quantum dynamics, we look at energy absorbed and transition probabilities as a function of the laser pulse time and also averaged over the pulse time. Calculations are performed for both rotating and nonrotating HF. We examine one and two photon absorption about the fundamental frequency, multiphoton absorption, and overtone absorption. 127 references, 31 figures, 12 tables

  20. Compilation of electron collision excitation cross sections for neutral argon

    International Nuclear Information System (INIS)

    Blanco, F.

    1993-01-01

    The present work presents a compilation and critical analysis of the available data on electron collision excitation cross sections for neutral Argon levels. This study includes: 1.- A detailed description in intermediate coupling for all the levels belonging the 20 configurations 3p5 ns (n=4to 12), np(n=4to8) and nd(n=3to8)of neutral Argon. 2.- Calculation of the electron collision excitation cross sections in Born and Born-Oppenheimer-Ochkur approximations for all the levels in the 14 configurations 3p5 ns (n=4 to 7), np (n=4 to 7) and nd (n=3 to 8). 3.- comparison and discussion of the compiled data. These are the experimental and theoretical values available from the literature, and those from this work. 4.- Analysis of the regularities and systematic behaviors in order to determine which values can be considered more reliable. It is show that the concept of one electron cross section results quite useful for this purpose. In some cases it has been possible to obtain in this way approximate analytical expressions interpolating the experimental data. 5.- All the experimental and theoretical values studied are graphically presented and compared. 6.- The last part of the work includes a listing of several general purpose programs for Atomic Physics calculations developed for this work. (Author) 35 refs

  1. Compilation of electron collision excitation cross sections for neutro argon

    International Nuclear Information System (INIS)

    Blanco Ramos, F.

    1993-01-01

    The present work presents a compilation and critical analysis of the available data on electron collision excitation cross sections for neutral Argon levels. This study includes: 1.- A detailed description in intermediate coupling for all the levels belonging the 20 configurations 3p''5 ns(n=4 to 12), np(n=4 to 8) and nd(n=3 to 8) of neutral Argon. 2.- Calculation of the electron collision excitation cross sections in Born and Born-Oppenheimer-Ochkur approximations for all the levels in the 14 configurations 3p''5 ns(n=4 to 7), np(n=4 to 7) and nd(n=3 to 8). 3.- Comparison and discussion of the compiled data. These are the experimental and theoretical values available from the literature, and those from this work. 4.- Analysis of the regularities and systematic behaviors in order to determine which values can be considered more reliable. It is show that the concept of one electron cross section results quite useful for this purpose. In some cases it has been possible to obtain in this way approximate analytical expressions interpolating the experimental data. 5.- All the experimental and theoretical values studied are graphically presented and compared. 6.- The last part of the work includes a listing of several general purpose programs for Atomic Physics calculations developed for this work. (Author)

  2. Compilation of electron collision excitation cross sections for neutral argon; Compilacion de resultados de secciones eficaces de excitacion para niveles del Argon neutro

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, F

    1993-07-01

    The present work presents a compilation and critical analysis of the available data on electron collision excitation cross sections for neutral Argon levels. This study includes: 1.- A detailed description in intermediate coupling for all the levels belonging the 20 configurations 3p5 ns (n=4to 12), np(n=4to8) and nd(n=3to8)of neutral Argon. 2.- Calculation of the electron collision excitation cross sections in Born and Born-Oppenheimer-Ochkur approximations for all the levels in the 14 configurations 3p5 ns (n=4 to 7), np (n=4 to 7) and nd (n=3 to 8). 3.- comparison and discussion of the compiled data. These are the experimental and theoretical values available from the literature, and those from this work. 4.- Analysis of the regularities and systematic behaviors in order to determine which values can be considered more reliable. It is show that the concept of one electron cross section results quite useful for this purpose. In some cases it has been possible to obtain in this way approximate analytical expressions interpolating the experimental data. 5.- All the experimental and theoretical values studied are graphically presented and compared. 6.- The last part of the work includes a listing of several general purpose programs for Atomic Physics calculations developed for this work. (Author) 35 refs.

  3. Theoretical study of quantum molecular reaction dynamics and of the effects of intense laser radiation on a diatomic molecule

    Energy Technology Data Exchange (ETDEWEB)

    Dardi, P.S.

    1984-11-01

    Within the very broad field of molecular dynamics, we have concentrated on two simple yet important systems. The systems are simple enough so that they are adequately described with a single Born-Oppenheimer potential energy surface and that the dynamics can be calculated accurately. They are important because they give insight into solving more complicated systems. First we discuss H + H/sub 2/ reactive scattering. We present an exact formalism for atom-diatom reactive scattering which avoids the problem of finding a coordinate system appropriate for both reactants and products. We present computational results for collinear H + H/sub 2/ reactive scattering which agree very well with previous calculations. We also present a coupled channel distorted wave Born approximation for atom-diatom reactive scattering which we show is a first order approximation to our exact formalism. We present coupled channel DWBA results for three dimensional H + H/sub 2/ reactive scattering. The second system is an isolated HF molecule in an intense laser field. Using classical trajectories and quantum dynamics, we look at energy absorbed and transition probabilities as a function of the laser pulse time and also averaged over the pulse time. Calculations are performed for both rotating and nonrotating HF. We examine one and two photon absorption about the fundamental frequency, multiphoton absorption, and overtone absorption. 127 references, 31 figures, 12 tables.

  4. Analytical and molecular dynamical investigations of the influence of molecular vibrations upon the (e,2e) electron momentum distributions of furan

    International Nuclear Information System (INIS)

    Morini, F; Deleuze, M S; Watanabe, N; Takahashi, M

    2015-01-01

    The role of molecular vibrations has been theoretically investigated in the electronic ground state on the (e, 2e) valence orbital momentum profiles of furan by means of two complementary approaches. The first one relies upon the principles of Born-Oppenheimer Molecular Dynamics (BOMD), whereas the second one, referred as Harmonic Analytical Quantum Mechanical (HAQM) approach, includes on quantum-mechanical (paper)

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

    Science.gov (United States)

    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.

  6. From Becquerel to Oppenheimer-Nuclear energy story

    International Nuclear Information System (INIS)

    Mataix, M.

    1994-02-01

    To tell the nuclear energy story is to tell the story of a science, which in less than a century was born in a small laboratory to reach a large industry level. This science upset the principles that physics established since the time origin and then left a mark the men story course and their way of life while arousing enthusiasm or rejection reactions that no human invention incited until then. Such a topic is critical to deal, the author does with much talent. He describes us these epic participants and the bonds that they kept up. He places their thoughts and works advance in the historical, sometimes turbulent context which was that of the century beginning. We will discover the personality of these scientists whose name is often recalled by a physical law or a measure unit, but who were first of all women and men applied to improve the human beings welfare while studying thoroughly the atom mysteries

  7. Simulating the spread of malaria using a generic transmission model for mosquito-borne infectious diseases

    Science.gov (United States)

    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.

  8. Understanding differences in alcohol consumption and depressed mood between U.S.- and foreign-born Asian and Caucasian college students.

    Science.gov (United States)

    Yeh, Jih-Cheng J; Hsu, Sharon H; Mittmann, Angela J; Litt, Dana; Geisner, Irene M

    2016-01-01

    The number and proportion of foreign-born individuals in the U.S. population has increased in recent decades. From 1970 to 2007, the foreign-born population more than tripled to approximately 37 million (U.S. Census Bureau, 1997 , 2008 ). Foreign-born students are a key subpopulation of college students. About 23% of U.S. undergraduate college students in 2007-2008 were either born outside of the United States (10%) or were children of at least one first-generation immigrant parent (13%; National Center for Education Statistics, U.S. Department of Education [NCES], 2012 ). Asian students constitute the majority (30%) of foreign-born undergraduates. Although foreign-born Asian students compose nearly one-quarter of the college population, limited research has examined how rates of alcohol use and depression differ between foreign-born and U.S.-born Asian college students (Gonzalez, Reynolds, & Skewes, 2011 ; Ralston & Palfai, 2012 ). The limited research is worrisome given their increasing rates of college enrollment (U.S. Census Bureau, 2011 ), alcohol consumption (Aud, Fox, & KewalRamani, 2010 ), alcohol abuse and dependence (Grant et al., 2004 ), and underutilization of mental health services (U.S. Department of Health and Human Services, 2001 ). Collectively, these factors point to the need for further research tailored to Asian college drinkers.

  9. Molecular physics. Theoretical principles and experimental methods

    International Nuclear Information System (INIS)

    Demtroeder, W.

    2005-01-01

    This advanced textbook comprehensively explains important principles of diatomic and polyatomic molecules and their spectra in two separate, distinct parts. The first part concentrates on the theoretical aspects of molecular physics, whereas the second part of the book covers experimental techniques, i.e. laser, Fourier, NMR, and ESR spectroscopies, used in the fields of physics, chemistry, biolog, and material science. Appropriate for undergraduate and graduate students in physics and chemistry with a knowledge of atomic physics and familiar with the basics of quantum mechanics. From the contents: - Electronic States of Molecules, - Rotation, Oscillation and Potential Curves of Diatomic Molecules, - The Spectra of Diatomic Molecules, - Molecule Symmetries and Group Theory, - Rotation and Oscillations of Polyatomic Molecules, - Electronic States of Polyatomic Molecules, - The Spectra of Polyatomic Molecules, - Collapse of the Born-Oppenheimer-Approximation, Disturbances in Molecular Spectra, - Molecules in Disturbing Fields, - Van-der-Waals-Molecules and Cluster, - Experimental Techniques in Molecular Physics. (orig.)

  10. Quantum physics of light and matter a modern introduction to photons, atoms and many-body systems

    CERN Document Server

    Salasnich, Luca

    2014-01-01

    The book gives an introduction to the field quantization (second quantization) of light and matter with applications to atomic physics. The first chapter briefly reviews the origins of special relativity and quantum mechanics and the basic notions of quantum information theory and quantum statistical mechanics. The second chapter is devoted to the second quantization of the electromagnetic field, while the third chapter shows the consequences of the light field quantization in the description of electromagnetic transitions.In the fourth chapter it is analyzed the spin of the electron, and in particular its derivation from the Dirac equation, while the fifth chapter investigates the effects of external electric and magnetic fields on the atomic spectra (Stark and Zeeman effects). The sixth chapter describes the properties of systems composed by many interacting identical particles by introducing the Hartree-Fock variational method, the density functional theory, and the Born-Oppenheimer approximation. Finally,...

  11. Tick-Borne Encephalitis (TBE)

    Science.gov (United States)

    ... virus, Siberian tick-borne encephalitis virus, and Far eastern Tick-borne encephalitis virus (formerly known as Russian ... viruses are closely related to TBEV and Far-eastern TBE, and include Omsk hemorrhagic fever virus in ...

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

    Science.gov (United States)

    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.

  13. The Born-Infeld action from conformal invariance of the open superstring

    International Nuclear Information System (INIS)

    Bergshoeff, E.; Sezgin, E.; Pope, C.N.; Townsend, P.K.

    1987-01-01

    We show that the one-loop approximation to sigma-model perturbation theory for the open superstring leads to the low energy effective action of Born-Infeld for the gauge field coupled to the ends of the string. Thus the bosonic part of the low-energy open superstring effective action is just that of the open bosonic string. We also show that these results are exact to all-loop orders of sigma-model perturbation theory. (author). 12 refs, 5 figs

  14. Differences in sleep habits, study time, and academic performance between US-born and foreign-born college students.

    Science.gov (United States)

    Eliasson, Arne H; Eliasson, Arn H; Lettieri, Christopher J

    2017-05-01

    To inform the design of a sleep improvement program for college students, we assessed academic performance, sleep habits, study hours, and extracurricular time, hypothesizing that there would be differences between US-born and foreign-born students. Questionnaires queried participants on bedtimes, wake times, nap frequency, differences in weekday and weekend sleep habits, study hours, grade point average, time spent at paid employment, and other extracurricular activities. Comparisons were made using chi square tests for categorical data and t tests for continuous data between US-born and foreign-born students. Of 120 participants (55 % women) with racial diversity (49 whites, 18 blacks, 26 Hispanics, 14 Asians, and 13 other), 49 (41 %) were foreign-born. Comparisons between US-born and foreign-born students showed no differences in average age or gender though US-born had more whites. There were no differences between US-born and foreign-born students for grade point averages, weekday bedtimes, wake times, or total sleep times. However, US-born students averaged 50 min less study time per day (p = 0.01), had almost 9 h less paid employment per week (14.5 vs 23.4 h per week, p = 0.001), and stayed up to socialize more frequently (63 vs 43 %, p = 0.03). Foreign-born students awakened an hour earlier and averaged 40 min less sleep per night on weekends. Cultural differences among college students have a profound effect on sleep habits, study hours, and extracurricular time. The design of a sleep improvement program targeting a population with diverse cultural backgrounds must factor in such behavioral variations in order to have relevance and impact.

  15. [Tick borne diseases].

    Science.gov (United States)

    Holzer, B R

    2005-11-01

    It is known for many years that tick-borne diseases have worldwide a high economical impact on farming industry and veterinary medicine. But only in the last twenty years the importance of such diseases were notified in human medicine by the medical community and the public with emerging of the tick borne encephalitis virus and the description of Borrelia burgdorferi. It is often forgotten that many other infectious agents as bacteria, virus, Rickettsia or protozoa can be transmitted by ticks. Such diseases are rarely diagnosed in Europe either they are overlooked and misdiagnosed or they are connected with special professional activities. The development of new regions for tourism with different out door activities (adventure trips, trekking, hunting) leads to an exposure to different tick borne diseases, which are often misdiagnosed.

  16. Where was Joseph Babinski born?

    Directory of Open Access Journals (Sweden)

    H A G Teive

    2011-01-01

    Full Text Available There is controversy in the neurological literature about where Joseph Babinski was born, including a myth propounded by various important authors that he was born in Lima, Peru. However, according to the most consistent biographical data, he was in fact born in Paris, France, and became a medical celebrity there and in Poland as well as around the world.

  17. A forward model for ground penetrating radar imaging of buried perfect electric conductors within the physical optics approximation

    DEFF Research Database (Denmark)

    Polat, Burak; Meincke, Peter

    2004-01-01

    A forward model for ground penetrating radar imaging of buried 3-D perfect electric conductors is addressed within the framework of diffraction tomography. The similarity of the present forward model derived within the physical optics approximation with that derived within the first Born...

  18. A comparison of efficient methods for the computation of Born gluon amplitudes

    International Nuclear Information System (INIS)

    Dinsdale, Michael; Ternick, Marko; Weinzierl, Stefan

    2006-01-01

    We compare four different methods for the numerical computation of the pure gluonic amplitudes in the Born approximation. We are in particular interested in the efficiency of the various methods as the number n of the external particles increases. In addition we investigate the numerical accuracy in critical phase space regions. The methods considered are based on (i) Berends-Giele recurrence relations, (ii) scalar diagrams, (iii) MHV vertices and (iv) BCF recursion relations

  19. Anharmonic vibrational properties in periodic systems: energy, electron-phonon coupling, and stress

    OpenAIRE

    Monserrat, Bartomeu; Drummond, N. D.; Needs, R. J.

    2013-01-01

    A unified approach is used to study vibrational properties of periodic systems with first-principles methods and including anharmonic effects. Our approach provides a theoretical basis for the determination of phonon-dependent quantities at finite temperatures. The low-energy portion of the Born-Oppenheimer energy surface is mapped and used to calculate the total vibrational energy including anharmonic effects, electron-phonon coupling, and the vibrational contribution to the stress tensor. W...

  20. Tick-borne disease.

    Science.gov (United States)

    Bratton, Robert L; Corey, Ralph

    2005-06-15

    Tick-borne diseases in the United States include Rocky Mountain spotted fever, Lyme disease, ehrlichiosis, tularemia, babesiosis, Colorado tick fever, and relapsing fever. It is important for family physicians to consider these illnesses when patients present with influenza-like symptoms. A petechial rash initially affecting the palms and soles of the feet is associated with Rocky Mountain spotted fever, whereas erythema migrans (annular macule with central clearing) is associated with Lyme disease. Various other rashes or skin lesions accompanied by fever and influenza-like illness also may signal the presence of a tick-borne disease. Early, accurate diagnosis allows treatment that may help prevent significant morbidity and possible mortality. Because 24 to 48 hours of attachment to the host are required for infection to occur, early removal can help prevent disease. Treatment with doxycycline or tetracycline is indicated for Rocky Mountain spotted fever, Lyme disease, ehrlichiosis, and relapsing fever. In patients with clinical findings suggestive of tick-borne disease, treatment should not be delayed for laboratory confirmation. If no symptoms follow exposure to tick bites, empiric treatment is not indicated. The same tick may harbor different infectious pathogens and transmit several with one bite. Advising patients about prevention of tick bites, especially in the summer months, may help prevent exposure to dangerous vector-borne diseases.

  1. Signatures of quantum gravity in a Born–Oppenheimer context

    International Nuclear Information System (INIS)

    Kamenshchik, Alexander Y.; Tronconi, Alessandro; Venturi, Giovanni

    2014-01-01

    We solve a general equation describing the lowest order corrections arising from quantum gravitational effects to the spectrum of cosmological fluctuations. The spectra of scalar and tensor perturbations are calculated to first order in the slow roll approximation and the results are compared with the most recent observations. The slow roll approximation gives qualitatively new quantum gravitational effects with respect to the pure de Sitter case

  2. Signatures of quantum gravity in a Born–Oppenheimer context

    Energy Technology Data Exchange (ETDEWEB)

    Kamenshchik, Alexander Y., E-mail: Alexander.Kamenshchik@bo.infn.it [Dipartimento di Fisica e Astronomia and INFN, Via Irnerio 46, 40126 Bologna (Italy); L.D. Landau Institute for Theoretical Physics of the Russian Academy of Sciences, Kosygin str. 2, 119334 Moscow (Russian Federation); Tronconi, Alessandro, E-mail: Alessandro.Tronconi@bo.infn.it [Dipartimento di Fisica e Astronomia and INFN, Via Irnerio 46, 40126 Bologna (Italy); Venturi, Giovanni, E-mail: Giovanni.Venturi@bo.infn.it [Dipartimento di Fisica e Astronomia and INFN, Via Irnerio 46, 40126 Bologna (Italy)

    2014-06-27

    We solve a general equation describing the lowest order corrections arising from quantum gravitational effects to the spectrum of cosmological fluctuations. The spectra of scalar and tensor perturbations are calculated to first order in the slow roll approximation and the results are compared with the most recent observations. The slow roll approximation gives qualitatively new quantum gravitational effects with respect to the pure de Sitter case.

  3. Born in Bradford, a cohort study of babies born in Bradford, and their parents: Protocol for the recruitment phase

    Directory of Open Access Journals (Sweden)

    Raynor Pauline

    2008-09-01

    Full Text Available Abstract Background Bradford, one of the most deprived cities in the United Kingdom, has a wide range of public health problems associated with socioeconomic deprivation, including an infant mortality rate almost double that for England and Wales. Infant mortality is highest for babies of Pakistani origin, who comprise almost half the babies born in Bradford. The Born in Bradford cohort study aims to examine environmental, psychological and genetic factors that impact on health and development perinatally, during childhood and subsequent adult life, and those that influence their parents' health and wellbeing. This protocol outlines methods for the recruitment phase of the study. Methods Most Bradford women attend for antenatal care and give birth at the Bradford Royal Infirmary, which has approximately 5,800 births per year. Women are eligible for recruitment if they plan to give birth here. Babies born from March 2007 are eligible to participate, recruitment is planned to continue until 2010. Fathers of babies recruited are invited to participate. Women are usually recruited when they attend for a routine oral glucose tolerance test at 26–28 weeks gestation. Recruitment of babies is at birth. Fathers are recruited whenever possible during the antenatal period, or soon after the birth. The aim is to recruit 10,000 women, their babies, and the babies' fathers. At recruitment women have blood samples taken, are interviewed to complete a semi-structured questionnaire, weighed, and have height, arm circumference and triceps skinfold measured. Umbilical cord blood is collected at birth. Within two weeks of birth babies have their head, arm and abdominal circumference measured, along with subscapular and triceps skinfold thickness. Fathers self-complete a questionnaire at recruitment, have height and weight measured, and provide a saliva sample. Participants are allocated a unique study number. NHS numbers will be used to facilitate record linkage

  4. A S-matrix-like approximation in the charged particle scattering by the hydrogen atom

    International Nuclear Information System (INIS)

    Mignaco, J.A.; Tort, A.C.

    1979-01-01

    The Born approximation for charged particle scattering by the hydrogen atom is unfit at low energies. From a S-matrix-like consideration on the dominance of the neighbour singularities, the calculation of other contributions is suggested. The inclusion of bound states is made, following Eden's and his colaborators' ideas, which are described by their interest and likeness with procedures in the intermediate energy physics. (Author) [pt

  5. Development of transition edge superconducting bolometers for the SAFARI Far-Infrared spectrometer on the SPICA space-borne telescope

    NARCIS (Netherlands)

    Mauskopf, P.; Morozov, D.; Glowacka, D.; Goldie, D.; Withington, S.; Bruijn, M.; De Korte, P.; Hoevers, H.; Ridder, M.; Van der Kuur, J.; Gao, J.R.

    2008-01-01

    We describe the optimization of transition edge superconducting (TES) detectors for use in a far-infrared (FIR) Fourier transform spectrometer (FTS) mounted on a cryogenically cooled space-borne telescope (e.g. SPICA). The required noise equivalent power (NEP) of the detectors is approximately 10?19

  6. Being an only or last-born child increases later risk of obesity.

    Directory of Open Access Journals (Sweden)

    Line K Haugaard

    Full Text Available BACKGROUND: Studies have suggested that number of siblings and birth order is associated with obesity. However, studies combining these exposures are needed. This study aimed at investigating obesity in children and young adults in regard to different combinations of family size and birth order. METHODS: Two cohorts selected from the general population were investigated: The Copenhagen School Health Records Register (CSHRR and a Draft Board (DB sample with measured heights and weights in childhood (age 13 years and young adulthood (age 19 years, respectively. Information on birth order, number of siblings, and relevant covariates were available on 29 327 children, as well as on 323 obese young men and 575 randomly selected controls of young men representing approximately 58 000. The relation between number of siblings and birth order, respectively, and having a Body Mass Index (BMI z-score above or equal to the 95(th percentile in childhood or having a BMI of at least 31.00 kg/m(2 in young adulthood was analysed using logistic regression analyses adjusted for relevant confounders. RESULTS: Only children had significantly higher odds of obesity both in childhood and in young adulthood compared with children with siblings, odds ratio (OR =1.44 (95% Confidence Interval (CI: 1.26-1.66 and OR=1.76 (95% CI: 1.18-2.61, respectively. No association between first-born status and obesity was found. The OR of last-born children being obese was also significantly increased in childhood, e.g. OR=1.93 (95% CI: 1.09-3.43 of obesity if last-born in a family of four children. This was not found in young adulthood. Additionally, higher spacing to previous sibling (average 1872 vs. 1303 days; p=0.026 in four children families was observed in obese last-born compared to non-obese last-born children. CONCLUSION: Being an only or last-born child is associated with obesity. These associations may provide leads to targeted prevention of obesity in children.

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

    Science.gov (United States)

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

    2013-05-01

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

  8. Influence of external extrusion on stability of hydrogen molecule and its chaotic behavior

    Science.gov (United States)

    Jarosik, M. W.; SzczÈ©śniak, R.; Durajski, A. P.; Kalaga, J. K.; Leoński, W.

    2018-01-01

    We have determined the stability conditions of the hydrogen molecule under the influence of an external force of harmonic-type explicitly dependent on the amplitude (A) and frequency (Ω). The ground state of the molecule has been determined in the framework of the Born-Oppenheimer approximation, whereas the energy of the electronic subsystem has been calculated using the Hubbard model including all two-site electron interactions. The diagram of RT0(A ,Ω) , where RT0 denotes the distance between protons after the fixed initial time T0, allowed us to visualize the area of the instability with the complicated structure. We have shown that the vibrations of the hydrogen molecule have a chaotic nature for some points of the instability region. In addition to the amplitude and frequency of the extrusion, the control parameter of the stability of the molecule is the external force associated with pressure. The increase in its value causes the disappearance of the area of the instability and chaotic vibrations.

  9. Extended Lagrangian Excited State Molecular Dynamics.

    Science.gov (United States)

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

    2018-02-13

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

  10. Non-adiabatic ab initio molecular dynamics of supersonic beam epitaxy of silicon carbide at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Taioli, Simone [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Department of Physics, University of Trento, Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (Italy); Department of Chemistry, University of Bologna, Bologna (Italy); Garberoglio, Giovanni [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Simonucci, Stefano [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (Italy); Department of Physics, University of Camerino, Camerino (Italy); Beccara, Silvio a [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Department of Physics, University of Trento, Trento (Italy); Aversa, Lucrezia [Institute of Materials for Electronics and Magnetism, IMEM-CNR, Trento (Italy); Nardi, Marco [Institute of Materials for Electronics and Magnetism, IMEM-CNR, Trento (Italy); Institut fuer Physik, Humboldt-Universitaet zu Berlin, Berlin (Germany); Verucchi, Roberto [Institute of Materials for Electronics and Magnetism, FBK-CNR, Trento (Italy); Iannotta, Salvatore [Institute of Materials for Electronics and Magnetism, IMEM-CNR, Parma (Italy); Dapor, Maurizio [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Department of Materials Engineering and Industrial Technologies, University of Trento, Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Padova (Italy); and others

    2013-01-28

    In this work, we investigate the processes leading to the room-temperature growth of silicon carbide thin films by supersonic molecular beam epitaxy technique. We present experimental data showing that the collision of fullerene on a silicon surface induces strong chemical-physical perturbations and, for sufficient velocity, disruption of molecular bonds, and cage breaking with formation of nanostructures with different stoichiometric character. We show that in these out-of-equilibrium conditions, it is necessary to go beyond the standard implementations of density functional theory, as ab initio methods based on the Born-Oppenheimer approximation fail to capture the excited-state dynamics. In particular, we analyse the Si-C{sub 60} collision within the non-adiabatic nuclear dynamics framework, where stochastic hops occur between adiabatic surfaces calculated with time-dependent density functional theory. This theoretical description of the C{sub 60} impact on the Si surface is in good agreement with our experimental findings.

  11. Electron-phonon interactions and intrinsic nonadiabatic state of superconductors

    International Nuclear Information System (INIS)

    Banacky, Pavol

    2007-01-01

    Study of band structure of YBa 2 Cu 3 O 7 has shown that electron coupling to A g , B 2g and B 3g modes results in fluctuation of saddle point of one of the CuO plane d-pσ band in Y point of 1st BZ across Fermi level. It represents breakdown of adiabatic Born-Oppenheimer approximation and transition of the system into intrinsic nonadiabatic state, ω > E F . Results show that system is stabilized in this state at distorted nuclear geometry. Stabilization effect is mainly due to strong dependence of the electronic motion on instantaneous nuclear momenta. On the lattice scale, the intrinsic nonadiabatic state is geometrically degenerate at broken translation symmetry - system has fluxional nuclear configuration of O2, O3 atoms in CuO planes. It enables formation of mobile bipolarons that can move in the lattice without dissipation. Described effects are absent in non-superconducting YBa 2 Cu 3 O 6

  12. Electron phonon interactions and intrinsic nonadiabatic state of superconductors

    Science.gov (United States)

    Baňacký, Pavol

    2007-09-01

    Study of band structure of YBa 2Cu 3O 7 has shown that electron coupling to A g, B 2g and B 3g modes results in fluctuation of saddle point of one of the CuO plane d-pσ band in Y point of 1st BZ across Fermi level. It represents breakdown of adiabatic Born-Oppenheimer approximation and transition of the system into intrinsic nonadiabatic state, ω > EF. Results show that system is stabilized in this state at distorted nuclear geometry. Stabilization effect is mainly due to strong dependence of the electronic motion on instantaneous nuclear momenta. On the lattice scale, the intrinsic nonadiabatic state is geometrically degenerate at broken translation symmetry - system has fluxional nuclear configuration of O2, O3 atoms in CuO planes. It enables formation of mobile bipolarons that can move in the lattice without dissipation. Described effects are absent in non-superconducting YBa 2Cu 3O 6.

  13. Probabilistic maps of the white matter tracts with known associated functions on the neonatal brain atlas: Application to evaluate longitudinal developmental trajectories in term-born and preterm-born infants.

    Science.gov (United States)

    Akazawa, Kentaro; Chang, Linda; Yamakawa, Robyn; Hayama, Sara; Buchthal, Steven; Alicata, Daniel; Andres, Tamara; Castillo, Deborrah; Oishi, Kumiko; Skranes, Jon; Ernst, Thomas; Oishi, Kenichi

    2016-03-01

    Diffusion tensor imaging (DTI) has been widely used to investigate the development of the neonatal and infant brain, and deviations related to various diseases or medical conditions like preterm birth. In this study, we created a probabilistic map of fiber pathways with known associated functions, on a published neonatal multimodal atlas. The pathways-of-interest include the superficial white matter (SWM) fibers just beneath the specific cytoarchitectonically defined cortical areas, which were difficult to evaluate with existing DTI analysis methods. The Jülich cytoarchitectonic atlas was applied to define cortical areas related to specific brain functions, and the Dynamic Programming (DP) method was applied to delineate the white matter pathways traversing through the SWM. Probabilistic maps were created for pathways related to motor, somatosensory, auditory, visual, and limbic functions, as well as major white matter tracts, such as the corpus callosum, the inferior fronto-occipital fasciculus, and the middle cerebellar peduncle, by delineating these structures in eleven healthy term-born neonates. In order to characterize maturation-related changes in diffusivity measures of these pathways, the probabilistic maps were then applied to DTIs of 49 healthy infants who were longitudinally scanned at three time-points, approximately five weeks apart. First, we investigated the normal developmental pattern based on 19 term-born infants. Next, we analyzed 30 preterm-born infants to identify developmental patterns related to preterm birth. Last, we investigated the difference in diffusion measures between these groups to evaluate the effects of preterm birth on the development of these functional pathways. Term-born and preterm-born infants both demonstrated a time-dependent decrease in diffusivity, indicating postnatal maturation in these pathways, with laterality seen in the corticospinal tract and the optic radiation. The comparison between term- and preterm-born

  14. Zero-point energy, tunnelling, and vibrational adiabaticity in the Mu + H2 reaction

    Science.gov (United States)

    Mielke, Steven L.; Garrett, Bruce C.; Fleming, Donald G.; Truhlar, Donald G.

    2015-01-01

    Isotopic substitution of muonium for hydrogen provides an unparalleled opportunity to deepen our understanding of quantum mass effects on chemical reactions. A recent topical review in this journal of the thermal and vibrationally state-selected reaction of Mu with H2 raises a number of issues that are addressed here. We show that some earlier quantum mechanical calculations of the Mu + H2 reaction, which are highlighted in this review, and which have been used to benchmark approximate methods, are in error by as much as 19% in the low-temperature limit. We demonstrate that an approximate treatment of the Born-Oppenheimer diagonal correction that was used in some recent studies is not valid for treating the vibrationally state-selected reaction. We also discuss why vibrationally adiabatic potentials that neglect bend zero-point energy are not a useful analytical tool for understanding reaction rates, and why vibrationally non-adiabatic transitions cannot be understood by considering tunnelling through vibrationally adiabatic potentials. Finally, we present calculations on a hierarchical family of potential energy surfaces to assess the sensitivity of rate constants to the quality of the potential surface.

  15. Asymptotic form of the charge-exchange cross section in three-body rearrangement collisions

    Science.gov (United States)

    Omidvar, K.

    1975-01-01

    A three-body general-type rearrangement collision is considered in which the initial and final bound states are described by hydrogen-like wave functions. It is shown that the charge-exchange amplitude in the first Born approximation can be expanded at all incident energies in terms of the inverse powers of the principal quantum number (n). By expanding the exchange amplitude in this way, it is demonstrated conclusively that the cross section for capture into the s, p, and d states as well as for the sum over all the angular-momentum states is proportional to 1/n-cubed plus terms proportional to higher inverse odd powers of n. It is found that the low-lying levels cannot be scaled to the 1/n-cubed law irrespective of the value of the incident energy except in the case of capture into the s states in accordance with the Oppenheimer-Brinkman-Kramers approximation. Zeros and minima in the differential cross sections are given in the limit of high principal quantum number for electron capture by protons from atomic hydrogen and for positronium formation by proton-atomic hydrogen collisions.

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

    International Nuclear Information System (INIS)

    Rule, D.W.; Omidvar, K.

    1979-01-01

    The charge equilibrium and radiation 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, are 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 of atomic shells of the target atoms and capture into all excited states of the projectile. The capture and loss cross sections are found to be within 20%--30% of the existing experimental values for most of the cases considered. Radiation of the beam due to electron capture into the excited states of the ion, collisional excitation, and collisional inner-shell ionization, taking into account the fluorescence yield of the ions has been considered. Effective X-ray production cross sections and mutliplicities for the most energetic X-ray lines emitted by the Fe and O beams have been calculated, and error estimates made for the results

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

    Science.gov (United States)

    Rule, D. W.; Omidvar, K.

    1979-01-01

    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, are 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 and capture into all excited states of the projectile. The capture and loss cross sections are found to be within 20%-30% of the existing experimental values for most of the cases considered. Radiation of the beam due to electron capture into the excited states of the ion, collisional excitation, and collisional inner-shell ionization, taking into account the fluorescence yield 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, and error estimates made for the results.

  18. The Dirac distorted wave Born approximation

    International Nuclear Information System (INIS)

    Cooper, T.; Sherif, H.S.; Johansson, J.; Sawafta, R.I.

    1985-02-01

    The purpose of this investigation is to illuminate the assumptions which are made when one writes down a Dirac DWBA matrix element. Due to the strong nature of the nucleon-nucleon potentials it is difficult to justify some of the steps involved in the general case; however by limiting ourselves to situations where only one (interacting) nucleon is present we can side-step this difficulty. We conclude the excellent agreement with the experiment justifies, a posteriori, the procedure, however we would like to remind the reader that, at least for proton inelastic scattering to collective states, the same quality of agreement can be obtained purely within a Schrodinger formalism

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

    Science.gov (United States)

    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.

  20. Prostate Cancer Prognostic Factors Among Asian Patients Born in the US Compared to Those Born Abroad.

    Science.gov (United States)

    Xu, Junjun; Goodman, Michael; Jemal, Ahemdin; Fedewa, Stacey A

    2015-06-01

    US surveillance data indicate that incidence of prostate cancer differs by place of birth among Asian men. However, it is less clear if the prognostic factors for prostate cancer also differ by place of birth. The study included 7,824 Asian prostate cancer patients diagnosed between 2004 and 2009 and reported to the Surveillance Epidemiology and End Results (SEER) program. Logistic regression models were used to evaluate the relation of place of birth (foreign born vs. US born) to three outcomes: prostate specific antigen (PSA) level, Gleason score, and T classification, adjusting for age, marital status, Rural-Urban Continuum Code, and SEER registry. All outcome variables were binary using different cutoffs: ≥ 4, ≥ 10 and ≥ 20 ng/ml for PSA; ≥ 7 and ≥ 8 for Gleason score; and ≥ T2 and ≥ T3 for T classification. Elevated PSA was more common among foreign born Asian men regardless of the cut point used. In the analysis comparing foreign born versus US born patients by ethnic group, the association with PSA was most pronounced at cut point of ≥ 20 ng/ml for Chinese men (OR 1.68, 95% CI 1.02-2.75), and at cut point of ≥ 4 ng/ml for Japanese men (OR 2.73, 95% CI 1.20-6.21). A statistically significant association with Gleason score was only found for Japanese men and only for the cutoff ≥ 7 (OR 1.71, 95% CI 1.12-2.61). There was no difference in clinical T classification between foreign-born and US-born Asian men. Inclusion of cases with missing place of birth or restriction of data to those who underwent radical prostatectomy did not substantially change the results. The data suggest that foreign-born Asian prostate cancer patients may have moderately elevated PSA levels at diagnosis compared with their US born counterparts. For the other prognostic markers, the associations were less consistent and did not form a discernible pattern.

  1. Microscopic calculation of the molecular-nuclear D+D → sup(3)He+n and D+D → sup(3)H+p reactions at close to zero energies

    International Nuclear Information System (INIS)

    Frederico, T.; Groote, J.J. de; Hornos, J.E.; Hussein, M.S.

    1990-11-01

    Microscopic calculations of the astrophysically interesting reactions D+D→sup(3)He+n and D+D→sup(3)H+p are performed using nuclear reaction theory and Born-Oppenheimer type molecular calculation of the D+D initial stage. The sensitivity of the fusion rate to the behaviour of the D+D wave function at close to zero separation is assessed. Relevance of the results to the cold fusion problem is discussed. (author)

  2. Geometric (Berry) phases in neutron molecular spectroscopy

    International Nuclear Information System (INIS)

    Lovesey, S.W.

    1992-02-01

    A theory of neutron scattering by nuclei in a molecule, accompanied by an electronic transition, is formulated with attention to gauge potentials and geometric phases in the Born-Oppenheimer scheme. Non-degenerate and nearly degenerate electronic levels are considered. For nearly degenerate levels it is shown that, the cross-section is free of the singular structure which characterizes the corresponding gauge potential for the phase, and much larger than for well separated electronic states. (author)

  3. Structure-borne noise at hotels

    Science.gov (United States)

    Wilson, George Paul; Jue, Deborah A.

    2002-11-01

    Hotels present a challenging environment for building designers to provide suitable noise and vibration isolation between very incompatible uses. While many are familiar with ways to reduce traditional sources of airborne noise and vibration, structure-borne noise and vibration are often overlooked, often with costly repercussions. Structure-borne noise can be very difficult to pinpoint, and troubleshooting the sources of the vibration can be a tedious process. Therefore, the best approach is to avoid the problem altogether during design, with attention to the building construction, potential vibration sources, building uses and equipment locations. In this paper, the relationship between structure-borne vibration and noise are reviewed, typical vibration sources discussed (e.g., aerobic rooms, laundry rooms, mechanical equipment/building services, and subway rail transit), and key details and design guidance to minimize structure-borne noise provided.

  4. Born : vastutustundlikud tulevikus edukad / Kerstin Born ; interv. Kristo Kiviorg

    Index Scriptorium Estoniae

    Born, Kerstin

    2007-01-01

    Vastutustundliku ettevõtluse Euroopa organisatsiooni CSR Europe'i juht Kerstin Born vastab küsimustele ettevõtete vastutustundlikkuse kohta ühiskonnas. Vt. samas: Käivitus vastutustundliku ettevõtluse indeks

  5. [Climate- and vector-borne diseases

    DEFF Research Database (Denmark)

    Bygbjerg, I.C.; Schioler, K.L.; Konradsen, F.

    2009-01-01

    The predicted changes in climate have raised concerns that vector-borne diseases may emerge or expand in tempered regions. Malaria, leishmaniasis and tick-borne illnesses are discussed in terms of climate change and their endemic potential, especially in Denmark. While climate may play an important...... role in disease patterns, it is evident that transmission potential is governed by a complex of factors, including socio-economy, health-care capacity and ecology. In Denmark, malaria and leishmaniasis are unlikely to become public health problems, whereas the potential for tick-borne illnesses may...

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

    Science.gov (United States)

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

    2010-01-01

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

  7. Diophantine approximation and badly approximable sets

    DEFF Research Database (Denmark)

    Kristensen, S.; Thorn, R.; Velani, S.

    2006-01-01

    . The classical set Bad of `badly approximable' numbers in the theory of Diophantine approximation falls within our framework as do the sets Bad(i,j) of simultaneously badly approximable numbers. Under various natural conditions we prove that the badly approximable subsets of Omega have full Hausdorff dimension...

  8. Foreign-born Peers and Academic Performance.

    Science.gov (United States)

    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.

  9. Offending Behavior, Drug Use, and Mental Health Among Foreign-Born versus U.S. Born Latino Criminal Justice Clients.

    Science.gov (United States)

    Ibañez, Gladys E; Agudo, Michelle; Martin, Steve S; O'Connell, Daniel J; Auf, Rehab; Sheehan, Diana M

    2017-06-01

    Little is known about the offending behavior and recidivism factors of Latinos by nativity (U.S. born, foreign-born). The present study focused on Latinos in community corrections (n = 201) in Miami, Florida, and examined differences in criminal activity, drug use, and mental health by nativity. Data were collected utilizing convenience sampling between June 2014 and December 2015. The research question was: what are the offending, drug use, and mental health histories of Latinos involved in community corrections? Participants were mostly male (n = 120; 59.7%), White (n = 105; 52.2%), and Cuban (n = 97; 48.3%). U.S. born community corrections clients (n = 141) were more likely to report more lifetime and recent criminal activity; and more likely to report lifetime and recent drug use behavior than foreign-born Latinos (n = 60). No differences were found in recent mental health. Correctional healthcare should tailor services such as substance abuse treatment differently toward U.S. born and foreign-born Latinos.

  10. Born iterative reconstruction using perturbed-phase field estimates.

    Science.gov (United States)

    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.

  11. Three-dimensional prospective evaluation of tooth-borne and bone-borne surgically assisted rapid maxillary expansion

    NARCIS (Netherlands)

    Nada, R.M.; Fudalej, P.S.; Maal, T.J.J.; Berge, S.J.; Mostafa, Y.A.; Kuijpers-Jagtman, A.M.

    2012-01-01

    AIM: To three-dimensionally (3D) assess the long-term effects of tooth-borne and bone-borne surgically assisted rapid maxillary expansion (SARME). SUBJECTS AND METHODS: This prospective cohort study comprised 45 consecutive skeletally mature non-syndromic patients with transverse maxillary

  12. Non-abelian Born-Infeld revisited

    NARCIS (Netherlands)

    Roo, M. de

    2002-01-01

    We discuss the non-abelian Born-Infeld action, including fermions, as a series in α'. We review recent work establishing the complete result to α'2, and its impact on our earlier attempts to derive the Born-Infeld action using κ-symmetry.

  13. [Climate- and vector-borne diseases

    DEFF Research Database (Denmark)

    Bygbjerg, I.C.; Schioler, K.L.; Konradsen, F.

    2009-01-01

    The predicted changes in climate have raised concerns that vector-borne diseases may emerge or expand in tempered regions. Malaria, leishmaniasis and tick-borne illnesses are discussed in terms of climate change and their endemic potential, especially in Denmark. While climate may play an important...

  14. The wild life of tick-borne pathogens

    OpenAIRE

    Hofmeester, Tim R.

    2016-01-01

    Diseases that are transmitted by arthropod vectors from animal hosts to humans – so called zoonotic vector-borne diseases – have increased in incidence in the last decades. In North America and Europe, tick-borne pathogens cause the majority of vector-borne diseases, including Lyme borreliosis and tick-borne encephalitis. The pathogens causing these diseases are transmitted by tick species within the Ixodes ricinus complex. These are generalist ticks that have a multi-year lifecycle with thre...

  15. Conceptualizing Innovation in Born Global Firms

    DEFF Research Database (Denmark)

    Zijdemans, Erik; Tanev, Stoyan

    2014-01-01

    This research provides insights from recent literature on innovativeness in the environment of born globals. This article will be relevant to researchers interested in born globals and their business environments and, more specifically, the role that innovation plays in their foundation and devel...... of knowledge acquisition, networking capabilities and the lean startup approach in born global innovation. Finally, the article addresses the issue of quantifying and measuring innovativeness....

  16. Theory of optical transitions in conjugated polymers. I. Ideal systems.

    Science.gov (United States)

    Barford, William; Marcus, Max

    2014-10-28

    We describe a theory of linear optical transitions in conjugated polymers. The theory is based on three assumptions. The first is that the low-lying excited states of conjugated polymers are Frenkel excitons coupled to local normal modes, described by the Frenkel-Holstein model. Second, we assume that the relevant parameter regime is ℏω ≪ J, i.e., the adiabatic regime, and thus the Born-Oppenheimer factorization of the electronic and nuclear degrees of freedom is generally applicable. Finally, we assume that the Condon approximation is valid, i.e., the exciton-polaron wavefunction is essentially independent of the normal modes. Using these assumptions we derive an expression for an effective Huang-Rhys parameter for a chain (or chromophore) of N monomers, given by S(N) = S(1)/IPR, where S(1) is the Huang-Rhys parameter for an isolated monomer. IPR is the inverse participation ratio, defined by IPR = (∑(n)|Ψ(n)|(4))(-1), where Ψ(n) is the exciton center-of-mass wavefunction. Since the IPR is proportional to the spread of the exciton center-of-mass wavefunction, this is a key result, as it shows that S(N) decreases with chain length. As in molecules, in a polymer S(N) has two interpretations. First, ℏωS(N) is the relaxation energy of an excited state caused by its coupling to the normal modes. Second, S(N) appears in the definition of an effective Franck-Condon factor, F(0v)(N) = S(N)(v)exp ( - S(N))/v! for the vth vibronic manifold. We show that the 0 - 0 and 0 - 1 optical intensities are proportional to F00(N) and F01(N), respectively, and thus the ratio of the 0 - 1 to 0 - 0 absorption and emission intensities are proportional to S(N). These analytical results are checked by extensive DMRG calculations and found to be generally valid, particularly for emission. However, for large chain lengths higher-lying quasimomentum exciton states become degenerate with the lowest vibrational excitation of the lowest exciton state. When this happens there is

  17. The wild life of tick-borne pathogens

    NARCIS (Netherlands)

    Hofmeester, Tim R.

    2016-01-01

    Diseases that are transmitted by arthropod vectors from animal hosts to humans – so called zoonotic vector-borne diseases – have increased in incidence in the last decades. In North America and Europe, tick-borne pathogens cause the majority of vector-borne diseases, including Lyme borreliosis

  18. On-the-energy-shell approximation for the heavy ion couple-channels problems

    International Nuclear Information System (INIS)

    Carlson, B.V.; Hussein, M.S.

    Starting with the coupled channels equations describing multiple Coulomb excitations in heavy ion collisions an approximation scheme is developed based on replacing the channel Green's functions by their on-the-energy shell forms, which permits an exact analytic solution for the scattering matrix. The trivially equivalent Coulomb polarization potential valid for strong coupling and small energy loss in the excitation processes is constructed. This potential is seen to have a very simple r-dependence. A simple formula for the sub-barrier elastic scattering cross section is then derived both by using the WRB approximation and by summing the Born series for the T-matrix. Comparison of the two forms for the elastic cross section shows that they give almost identical numerical results in the small coupling limit only. The results are also compared with the predictions of the Alder-Winther theory. (Author) [pt

  19. Work Disability Among Native-born and Foreign-born Americans: On Origins, Health, and Social Safety Nets.

    Science.gov (United States)

    Engelman, Michal; Kestenbaum, Bert M; Zuelsdorff, Megan L; Mehta, Neil K; Lauderdale, Diane S

    2017-12-01

    Public debates about both immigration policy and social safety net programs are increasingly contentious. However, little research has explored differences in health within America's diverse population of foreign-born workers, and the effect of these workers on public benefit programs is not well understood. We investigate differences in work disability by nativity and origins and describe the mix of health problems associated with receiving Social Security Disability Insurance benefits. Our analysis draws on two large national data sources-the American Community Survey and comprehensive administrative records from the Social Security Administration-to determine the prevalence and incidence of work disability between 2001 and 2010. In sharp contrast to prior research, we find that foreign-born adults are substantially less likely than native-born Americans to report work disability, to be insured for work disability benefits, and to apply for those benefits. Overall and across origins, the foreign-born also have a lower incidence of disability benefit award. Persons from Africa, Northern Europe, Canada, and parts of Asia have the lowest work disability benefit prevalence rates among the foreign-born; persons from Southern Europe, Western Europe, the former Soviet Union, and the Caribbean have the highest rates.

  20. Bird of passage recollections of a physicist

    CERN Document Server

    1985-01-01

    Here is the intensely personal and often humorous autobiography of one of the most distinguished theoretical physicists of his generation, Sir Rudolf Peierls. Born in Germany in 1907, Peierls was indeed a bird of passage," whose career of fifty-five years took him to leading centers of physics--including Munich, Leipzig, Zurich, Copenhagen, Cambridge, Manchester, Oxford, and J. Robert Oppenheimer''s Los Alamos. Peierls was a major participant in the revolutionary development of quantum mechanics in the 1920s and 1930s, working with some of the pioneers and, as he puts it, "some of the great characters" in this field. Originally published in 1988. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of- print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Libr...

  1. The effects of pseudo magnetic fields in molecular spectra and scattering

    International Nuclear Information System (INIS)

    Kendrick, B.K.

    1996-01-01

    Pseudo magnetic fields appear in the Born-Oppenheimer method for molecules when conical intersections or electronic angular momenta are taken into account. These fields are not real magnetic fields but they have the same mathematical properties and can lead to real observable effects in the dynamics of molecules. A general vector potential (gauge theory) approach for including these field effects in the Born-Oppenheimer method is introduced and applied to H + O 2 scattering and the vibrational spectrum of Na 3 (X) for zero total angular momentum (J = 0). The scattering results for HO 2 show significant shifts in the resonance energies and lifetimes due to a magnetic solenoid type field originating from the C 2v conical intersection in HO 2 . Significant changes in the state-to-state transition probabilities are also observed. The non-degenerate A 1 and A 2 vibrational spectra of Na 3 (X) show significant shifts in the energy levels due to a magnetic solenoid type field originating from the D 3h conical intersection in Na 3 . These two examples show that the effects of pseudo magnetic fields can be significant and in many cases they must be included in order to obtain agreement between theory and experiment. The newly developed gauge theory techniques for treating pseudo magnetic fields are also relevant for including the effects of real magnetic fields

  2. Physical Fitness in Young Adults Born Preterm.

    Science.gov (United States)

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

    2016-01-01

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

  3. Diatomic molecule vibrational potentials: Accuracy of representations

    International Nuclear Information System (INIS)

    Engelke, R.

    1978-01-01

    A method is presented for increasing the radius of convergence of certain representations of diatomic molecule vibrational potentials. The method relies on using knowledge of the analytic structure of such potentials to the maximum when attempting to approximate them. The known singular point (due to the centrifugal and/or Coulomb potentials) at zero internuclear separation should be included in its exact form in an approximate representation. The efficacy of this idea is tested [using Peek's ''exact'' numerical Born-Oppenheimer potential for the (1ssigma/sub g/) 2 Σ + /sub g/ state of H + 2 as a test problem] when the representational form is the series of (1) Dunham, (2) Simons, Parr, and Finlan, (3) Thakkar, and (4) Ogilvie-Tipping, and also (5) when the form is a [2, 2] or a [3, 3] Pade approximant. Significant improvements in accuracy are obtained in some of these cases, particularly on the inner wall of the potential. A comparison of the effectiveness of the five methods is made both with and without the origin behavior being included exactly. This is useful in itself as no comprehensive accuracy comparison of the standard representations seems to have appeared in the literature. The Ogilvie-Tipping series, corrected at the origin for singular behavior, is the best representation presently available for states analogous to the (1ssigma/sub g/) 2 Σ + /sub g/ state of H + 2

  4. Dipole and quadrupole forces exerted on atoms in laser fields: The nonperturbative approach

    International Nuclear Information System (INIS)

    Sindelka, Milan; Moiseyev, Nimrod; Cederbaum, Lorenz S.

    2006-01-01

    Manipulation of cold atoms by lasers has so far been studied solely within the framework of the conventional dipole approximation, and the atom-light interaction has been treated using low order perturbation theory. Laser control of atomic motions has been ascribed exclusively to the corresponding light-induced dipole forces. In this work, we present a general theory to derive the potential experienced by an atom in a monochromatic laser field in a context analogous to the Born-Oppenheimer approximation for molecules in the field-free case. The formulation goes beyond the dipole approximation and gives rise to the field-atom coupling potential terms which so far have not been taken into consideration in theoretical or experimental studies. Contrary to conventional approaches, our method is based upon the many electron Floquet theory and remains valid also for high intensity laser fields (i.e., for a strongly nonperturbative atom-light interaction). As an illustration of the developed theory, we investigate the trapping of cold atoms in optical lattices. We find that for some atoms for specific laser parameters, despite the absence of the dipole force, the laser trapping is still possible due to the electric quadrupole forces. Namely, we show that by using realistic laser parameters one can form a quadrupole optical lattice which is sufficiently strong to trap Ca and Na atoms

  5. Two-dimensional gauge dynamics and the topology of singular determinantal varieties

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Kenny [Department of Applied Mathematics and Theoretical Physics,Centre for Mathematical Sciences, University of Cambridge,Cambridge, CB3 0WA (United Kingdom)

    2017-03-27

    We record an observation about the Witten indices in two families of gauged linear sigma models: the U(2) model for linear sections of Grassmannians, and the U(1) model for quadric complete intersections. We describe how the Witten indices are related to the Euler characteristics of the singular skew-symmetric or symmetric determinantal varieties featuring in the analysis of their opposite phases, and we discuss the extent to which these relationships can be reconciled with standard Born-Oppenheimer arguments.

  6. Electronic structure, molecular bonding and potential energy surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ruedenberg, K. [Ames Laboratory, IA (United States)

    1993-12-01

    By virtue of the universal validity of the generalized Born-Oppenheimer separation, potential energy surfaces (PES`) represent the central conceptual as well as quantitative entities of chemical physics and provide the basis for the understanding of most physicochemical phenomena in many diverse fields. The research in this group deals with the elucidation of general properties of PES` as well as with the quantitative determination of PES` for concrete systems, in particular pertaining to reactions involving carbon, oxygen, nitrogen and hydrogen molecules.

  7. Performance of the CAPRICE98 balloon-borne gas-RICH detector

    CERN Document Server

    Bergström, D; Carlson, P J; Francke, T; Grinstein, S; Weber, N; Suffert, Martin; Hof, M; Kremer, J; Menn, W; Simon, M; Stephens, S A; Ambriola, M; Bellotti, R; Cafagna, F; Castellano, M G; Ciacio, F; Circella, M; De Marzo, C; Finetti, N; Papini, P; Piccardi, S; Spillantini, P; Bartalucci, S; Ricci, M; Bidoli, V; Casolino, M; De Pascale, M P; Morselli, A; Picozza, P; Sparvoli, R; Barbiellini, Guido; Schiavon, R P; Vacchi, A; Zampa, N; Mitchell, J W; Ormes, J F; Streitmatter, R E; Bravar, U; Stochaj, S J

    2001-01-01

    A RICH counter using a gas radiator of C/sub 4/F/sub 10/ and a photosensitive MWPC with pad readout has been developed, tested in particle beam at CERN and used in the CAPRICE98 balloon-borne experiment. The MWPC was operated with a TMAE and ethane mixture at atmospheric pressure and used a cathode pad plane to give an unambiguous image of the Cherenkov light. The induced signals in the pad plane were read our using the AMPLEX chip and CRAMS. The good efficiency of the Cherenkov light collection, the efficient detection of the weak signal from single UV photons together with a low noise level in the electronics of the RICH detector, resulted in a large number of detected photoelectrons per event. For beta approximately=1 charge one particles, an average of 12 photoelectrons per event were detected. The reconstructed Cherenkov angle of 50 mrad for a beta approximately=1 particle had a resolution of 1.2 mrad (rms). The RICH was flown with the CAPRICE98 magnetic spectrometer and was the first RICH counter ever u...

  8. Iterative Multiparameter Elastic Waveform Inversion Using Prestack Time Imaging and Kirchhoff approximation

    Science.gov (United States)

    Khaniani, Hassan

    This thesis proposes a "standard strategy" for iterative inversion of elastic properties from the seismic reflection data. The term "standard" refers to the current hands-on commercial techniques that are used for the seismic imaging and inverse problem. The method is established to reduce the computation time associated with elastic Full Waveform Inversion (FWI) methods. It makes use of AVO analysis, prestack time migration and corresponding forward modeling in an iterative scheme. The main objective is to describe the iterative inversion procedure used in seismic reflection data using simplified mathematical expression and their numerical applications. The frame work of the inversion is similar to (FWI) method but with less computational costs. The reduction of computational costs depends on the data conditioning (with or without multiple data), the level of the complexity of geological model and acquisition condition such as Signal to Noise Ratio (SNR). Many processing methods consider multiple events as noise and remove it from the data. This is the motivation for reducing the computational cost associated with Finite Difference Time Domain (FDTD) forward modeling and Reverse Time Migration (RTM)-based techniques. Therefore, a one-way solution of the wave equation for inversion is implemented. While less computationally intensive depth imaging methods are available by iterative coupling of ray theory and the Born approximation, it is shown that we can further reduce the cost of inversion by dropping the cost of ray tracing for traveltime estimation in a way similar to standard Prestack Time Migration (PSTM) and the corresponding forward modeling. This requires the model to have smooth lateral variations in elastic properties, so that the traveltime of the scatterpoints can be approximated by a Double Square Root (DSR) equation. To represent a more realistic and stable solution of the inverse problem, while considering the phase of supercritical angles, the

  9. How do we decide whether the first Born approximation applies to inelastic collisions of charged particles with an atom or molecule

    International Nuclear Information System (INIS)

    Inokuti, M.; Manson, S.T.

    1985-01-01

    A motivation of our study is to help resolve a general issue in atomic-collision physics. There are two major sources of uncertainties in the evaluation of cross sections. First, one uses an approximation for treating the collision process, e.g., the FBA, the distorted-wave approximation, or the close-coupling approximation. Second, explicit evaluation of cross sections within any of these approximations must use as input eigenfunctions for the target in the initial state and in the final state at least, and possibly in the intermediate states. It is important to distinguish these two sources of uncertainties as clearly as possible. For instance, once the authors are sure that the FBA holds, the uncertainties in the cross-section evaluation are fully attributable to the uncertainties in the target eigenfunctions. Strong plausibility arguments are given for the validity of the FBA

  10. Mortality differences between the foreign-born and locally-born population in France (2004-2007).

    Science.gov (United States)

    Boulogne, Roxane; Jougla, Eric; Breem, Yves; Kunst, Anton E; Rey, Grégoire

    2012-04-01

    In contrast to the situation in many European countries, the mortality of immigrants in France has been little studied. The main reasons for the lack of studies are based on ethical and ideological considerations. The objective of this study is to explore mortality by country of birth in Metropolitan (i.e. 'mainland') France. Complete mortality data were used to study the relative risks of mortality of the foreign- and locally-born populations by gender, age and cause of death for the period 2004-2007 in Metropolitan France. Analyses were conducted by countries of birth grouped into geographic areas and by the Human Development Index (HDI). The differentials in mortality between foreign-born and locally-born populations were not homogeneous. The figures varied by age (higher foreign-born mortality for the young; lower mortality for migrants aged 15-64 years), gender (female migrants more frequently had higher relative mortality than men migrants), country of birth (Eastern European-born migrants had higher mortality, while those born in Morocco, Central Asia, 'other Asian countries' and America had lower mortality) and cause of death (migrant mortality was higher overall for deaths caused by infectious diseases and diabetes, and lower for violent death and neoplasm). Moreover, mortality relative risks for male, violent deaths and cancer were positively associated with country-of-birth HDI, while female mortality and infectious disease mortality were negatively associated with country-of-birth HDI. Some important caveats have to be considered because the study did not control for individuals socioeconomic position in France, or length of residence in the host country. A strong healthy migrant effect was suggested and its intensity varies with age and gender (which may reflect different reasons for migration). For some specific causes of death, a lifestyle effect seems to explain mortality differentials. The associations between HDI and mortality show that mortality

  11. OUTCOMES OF TICK-BORNE ENCEPHALITIS IN THE TOMSK REGION

    Directory of Open Access Journals (Sweden)

    T. S. Pinegina

    2013-01-01

    Full Text Available The results of the study outcomes of tick-borne encephalitis in adults in the Tomsk Region. Patients conducted a comprehensive clinical and laboratory examination. Revealed the prevalence of autonomic disorders in individuals who have had at different periods of tick-borne encephalitis, which is regarded as the effects of tick-borne infection. Residual effects of tick-borne encephalitis occurs mainly in the form of light paresis after suffering a focal forms. Among the chronic (progredient forms of tick-borne encephalitis often formed hyperkinetic options. Most of the study revealed the presence of precipitating factors that could have an influence on the outcome. Fundamental diffe rences in all-clinical and immunological analyses at patients with various outcomes of tick-borne encephalitis it wasn't noted. KEY WORDS: tick-borne encephalitis, Tomsk Region, the outcomes.

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

    Directory of Open Access Journals (Sweden)

    Yecai Liu

    Full Text Available 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

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

    Science.gov (United States)

    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

  14. Air travel and vector-borne disease movement.

    Science.gov (United States)

    Tatem, A J; Huang, Z; Das, A; Qi, Q; Roth, J; Qiu, Y

    2012-12-01

    Recent decades have seen substantial expansions in the global air travel network and rapid increases in traffic volumes. The effects of this are well studied in terms of the spread of directly transmitted infections, but the role of air travel in the movement of vector-borne diseases is less well understood. Increasingly however, wider reaching surveillance for vector-borne diseases and our improving abilities to map the distributions of vectors and the diseases they carry, are providing opportunities to better our understanding of the impact of increasing air travel. Here we examine global trends in the continued expansion of air transport and its impact upon epidemiology. Novel malaria and chikungunya examples are presented, detailing how geospatial data in combination with information on air traffic can be used to predict the risks of vector-borne disease importation and establishment. Finally, we describe the development of an online tool, the Vector-Borne Disease Airline Importation Risk (VBD-Air) tool, which brings together spatial data on air traffic and vector-borne disease distributions to quantify the seasonally changing risks for importation to non-endemic regions. Such a framework provides the first steps towards an ultimate goal of adaptive management based on near real time flight data and vector-borne disease surveillance.

  15. The quantum realm of the ''Little Sibling'' of the Big Rip singularity

    International Nuclear Information System (INIS)

    Albarran, Imanol; Bouhmadi-López, Mariam; Cabral, Francisco; Martín-Moruno, Prado

    2015-01-01

    We analyse the quantum behaviour of the ''Little Sibling'' of the Big Rip singularity (LSBR) [1]. The quantisation is carried within the geometrodynamical approach given by the Wheeler-DeWitt (WDW) equation. The classical model is based on a Friedmann-Lemaître-Robertson-Walker Universe filled by a perfect fluid that can be mapped to a scalar field with phantom character. We analyse the WDW equation in two setups. In the first step, we consider the scale factor as the single degree of freedom, which from a classical perspective parametrises both the geometry and the matter content given by the perfect fluid. We then solve the WDW equation within a WKB approximation, for two factor ordering choices. On the second approach, we consider the WDW equation with two degrees of freedom: the scale factor and a scalar field. We solve the WDW equation, with the Laplace-Beltrami factor-ordering, using a Born-Oppenheimer approximation. In both approaches, we impose the DeWitt (DW) condition as a potential criterion for singularity avoidance. We conclude that in all the cases analysed the DW condition can be verified, which might be an indication that the LSBR can be avoided or smoothed in the quantum approach

  16. Enhanced Electron-Phonon Coupling at Metal Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Plummer, Ward E.

    2010-08-04

    The Born-Oppenheimer approximation (BOA) decouples electronic from nuclear motion, providing a focal point for most quantum mechanics textbooks. However, a multitude of important chemical, physical and biological phenomena are driven by violations of this approximation. Vibronic interactions are a necessary ingredient in any process that makes or breaks a covalent bond, for example, conventional catalysis or enzymatically delivered biological reactions. Metastable phenomena associated with defects and dopants in semiconductors, oxides, and glasses entail violation of the BOA. Charge exchange in inorganic polymers, organic slats and biological systems involves charge- induced distortions of the local structure. A classic example is conventional superconductivity, which is driven by the electron-lattice interaction. High-resolution angle-resolved photoemission experiments are yielding new insight into the microscopic origin of electron-phonon coupling (EPC) in anisotropic two-dimensional systems. Our recent surface phonon measurement on the surface of a high-Tc material clearly indicates an important momentum dependent EPC in these materials. In the last few years we have shifted our research focus from solely looking at electron phonon coupling to examining the structure/functionality relationship at the surface of complex transition metal compounds. The investigation on electron phonon coupling has allowed us to move to systems where there is coupling between the lattice, the electrons and the spin.

  17. Multiple Scattering Model for Optical Coherence Tomography with Rytov Approximation

    KAUST Repository

    Li, Muxingzi

    2017-04-24

    Optical Coherence Tomography (OCT) is a coherence-gated, micrometer-resolution imaging technique that focuses a broadband near-infrared laser beam to penetrate into optical scattering media, e.g. biological tissues. The OCT resolution is split into two parts, with the axial resolution defined by half the coherence length, and the depth-dependent lateral resolution determined by the beam geometry, which is well described by a Gaussian beam model. The depth dependence of lateral resolution directly results in the defocusing effect outside the confocal region and restricts current OCT probes to small numerical aperture (NA) at the expense of lateral resolution near the focus. Another limitation on OCT development is the presence of a mixture of speckles due to multiple scatterers within the coherence length, and other random noise. Motivated by the above two challenges, a multiple scattering model based on Rytov approximation and Gaussian beam optics is proposed for the OCT setup. Some previous papers have adopted the first Born approximation with the assumption of small perturbation of the incident field in inhomogeneous media. The Rytov method of the same order with smooth phase perturbation assumption benefits from a wider spatial range of validity. A deconvolution method for solving the inverse problem associated with the first Rytov approximation is developed, significantly reducing the defocusing effect through depth and therefore extending the feasible range of NA.

  18. Using geographical information systems to explore disparities in preterm birth rates among foreign-born and U.S.-born Black mothers.

    Science.gov (United States)

    Bloch, Joan Rosen

    2011-01-01

    To examine spatial patterns of neighborhood contextual factors of stress with preterm birth (PTB) and nativity (foreign-born and U.S.-born) among Black mothers. Descriptive geographic-spatial research. Births to Philadelphia residents during 2003-2005 in the context of Philadelphia residential neighborhoods (N = 350) were studied. All data were aggregated to neighborhood levels (census tracts). Maps were created to assess geographic-spatial patterns. A geographic information system (GIS) database was created that imported geo-coded data on births, crime (assaults with guns and domestic abuse), poverty, race, and nativity (foreign-born vs. U.S.-born). Clear visual patterns of "bad" neighborhoods emerged and were significantly associated with higher prevalence of PTB for foreign-born Black and U.S.-born Black mothers (p < .0001). This study demonstrated how GIS visually clarified important spatial patterns of adverse living conditions and PTB prevalence. Nurses can use GIS to better understand living environments of mothers and their families and to target interventions in geographical areas with the greatest service needs. Further research on individual and contextual factors is warranted to address the observed health disparities among the heterogeneous groups of foreign-born Black mothers. Despite limitations of aggregate data, it is clear that where mothers live matters. This has important implications for nursing practice and policy. © 2011 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses.

  19. Using Geographical Information Systems to Explore Disparities in Preterm Birth Rates Among Foreign-born and U.S.-born Black Mothers

    Science.gov (United States)

    Bloch, Joan Rosen

    2012-01-01

    Objective To examine spatial patterns of neighborhood contextual factors of stress with preterm birth (PTB) and nativity (foreign-born and U.S.-born) among Black mothers. Design Descriptive geographic-spatial research. Setting & Participants Births to Philadelphia residents during 2003–2005 in the context of Philadelphia residential neighborhoods (N = 350) were studied. Methods All data were aggregated to neighborhood levels (census tracts). Maps were created to assess geographic-spatial patterns. A geographic information system (GIS) database was created that imported geo-coded data on births, crime (assaults with guns and domestic abuse), poverty, race, and nativity (foreign-born vs. U.S.-born). Results Clear visual patterns of “bad” neighborhoods emerged and were significantly associated with higher prevalence of PTB for foreign-born Black and U.S.-born Black mothers (p GIS visually clarified important spatial patterns of adverse living conditions and PTB prevalence. Nurses can use GIS to better understand living environments of mothers and their families and to target interventions in geographical areas with the greatest service needs. Further research on individual and contextual factors is warranted to address the observed health disparities among the heterogeneous groups of foreign-born Black mothers. Despite limitations of aggregate data, it is clear that where mothers live matters. This has important implications for nursing practice and policy. PMID:22273411

  20. Wavefield separation by energy norm Born scattering

    KAUST Repository

    Sun, Bingbing

    2017-08-17

    In Reflection Based Waveform Inversion, the gradient is computed by cross-correlating the direct and Born scattered wavefield with their adjoints applied to the data residuals. In this case, the transmitted part of the Born scattered wavefield produces high wavenumber artifacts, which would harm the convergence of the inversion process. We propose an efficient Energy Norm Born Scattering (ENBS) to attenuate the transmission components of the Born modeling, and allow it to produce only reflections. ENBS is derived from the adjoint of the Energy Norm (inverse scattering) imaging condition and in order to get deeper insights of how this method works, we show analytically that given an image, in which reflectivity is represented by a Dirac delta function, ENBS attenuates transmission energy perfectly. We use numerical examples to demonstrate that ENBS works in both the time and the frequency domain. We also show that in reflection waveform inversion (RWI) the wave path constructed by ENBS would be cleaner and free of high wavenumber artifacts associated with conventional Born scattering.

  1. Wavefield separation by energy norm Born scattering

    KAUST Repository

    Sun, Bingbing; Alkhalifah, Tariq Ali

    2017-01-01

    In Reflection Based Waveform Inversion, the gradient is computed by cross-correlating the direct and Born scattered wavefield with their adjoints applied to the data residuals. In this case, the transmitted part of the Born scattered wavefield produces high wavenumber artifacts, which would harm the convergence of the inversion process. We propose an efficient Energy Norm Born Scattering (ENBS) to attenuate the transmission components of the Born modeling, and allow it to produce only reflections. ENBS is derived from the adjoint of the Energy Norm (inverse scattering) imaging condition and in order to get deeper insights of how this method works, we show analytically that given an image, in which reflectivity is represented by a Dirac delta function, ENBS attenuates transmission energy perfectly. We use numerical examples to demonstrate that ENBS works in both the time and the frequency domain. We also show that in reflection waveform inversion (RWI) the wave path constructed by ENBS would be cleaner and free of high wavenumber artifacts associated with conventional Born scattering.

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

    Science.gov (United States)

    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

  3. Quantum-classical dynamics of scattering processes in adiabatic and diabatic representations

    International Nuclear Information System (INIS)

    Puzari, Panchanan; Sarkar, Biplab; Adhikari, Satrajit

    2004-01-01

    We demonstrate the workability of a TDDVR based [J. Chem. Phys. 118, 5302 (2003)], novel quantum-classical approach, for simulating scattering processes on a quasi-Jahn-Teller model [J. Chem. Phys. 105, 9141 (1996)] surface. The formulation introduces a set of DVR grid points defined by the Hermite part of the basis set in each dimension and allows the movement of grid points around the central trajectory. With enough trajectories (grid points), the method converges to the exact quantum formulation whereas with only one grid point, we recover the conventional molecular dynamics approach. The time-dependent Schroedinger equation and classical equations of motion are solved self-consistently and electronic transitions are allowed anywhere in the configuration space among any number of coupled states. Quantum-classical calculations are performed on diabatic surfaces (two and three) to reveal the effects of symmetry on inelastic and reactive state-to-state transition probabilities, along with calculations on an adiabatic surface with ordinary Born-Oppenheimer approximation. Excellent agreement between TDDVR and DVR results is obtained in both the representations

  4. The role of high-level calculations in the assignment of the Q-band spectra of chlorophyll

    Energy Technology Data Exchange (ETDEWEB)

    Reimers, Jeffrey R. [School of Physics and Materials Science, The University of Technology, Sydney NSW (Australia); Cai, Zheng-Li [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane QLD4001 (Australia); Kobayashi, Rika [Australian National University Supercomputer Facility, Mills Rd, Canberra, ACT 0200 (Australia); Rätsep, Margus [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia); Freiberg, Arvi [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu, Estonia and Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu (Estonia); Krausz, Elmars [Research School of Chemistry, The Australian National University, Canberra 2601 (Australia)

    2014-10-06

    We recently established a novel assignment of the visible absorption spectrum of chlorophyll-a that sees the two components Q{sub x} and Q{sub y} of the low-energy Q band as being intrinsically mixed by non-adiabatic coupling. This ended 50 years debate as to the nature of the Q bands, with prior discussion poised only in the language of the Born-Oppenheimer and Condon approximations. The new assignment presents significant ramifications for exciton transport and quantum coherence effects in photosystems. Results from state of the art electronic structure calculations have always been used to justify assignments, but quantitative inaccuracies and systematic failures have historically limited usefulness. We examine the role of CAM-B3LYP time-dependent density-functional theory (TD-DFT) and Symmetry Adapted Cluster-Configuration Interaction (SAC-CI) calculations in first showing that all previous assignments were untenable, in justifying the new assignment, in making some extraordinary predictions that were vindicated by the new assignment, and in then identifying small but significant anomalies in the extensive experimental data record.

  5. H2+ embedded in a Debye plasma: Electronic and vibrational properties

    International Nuclear Information System (INIS)

    Angel, M.L.; Montgomery, H.E.

    2011-01-01

    The effect of plasma screening on the electronic and vibrational properties of the H 2 + molecular ion was analyzed within the Born-Oppenheimer approximation. When a molecule is embedded in a plasma, the plasma screens the electrostatic interactions. This screening is accounted in the Schroedinger equation by replacing the Coulomb potentials with Yukawa potentials that incorporate the Debye length as a screening parameter. Variational expansions in confocal elliptical coordinates were used to calculate energies of the 1sσ g and 2pσ u states over a range of Debye lengths and bond distances. When the Debye length is comparable to the equilibrium bond distance, the dissociation energy is reduced while the equilibrium internuclear separation is increased. Expectation values, static dipole polarizabilities and spectroscopic constants were calculated for the 1sσ g state. - Highlights: → Effect of plasma screening on the properties of the H 2 + molecular ion. → Used a variational wavefunction in confocal elliptical coordinates. → Potential energy curves for the ground and first excited state are presented. → Decreasing Debye length increases polarizability of the electron distribution.

  6. Ab initio molecular dynamics: basic concepts, current trends and novel applications

    International Nuclear Information System (INIS)

    Tuckerman, Mark E

    2002-01-01

    The field of ab initio molecular dynamics (AIMD), in which finite temperature molecular dynamics (MD) trajectories are generated with forces obtained from accurate 'on the fly' electronic structure calculations, is a rapidly evolving and growing technology that allows chemical processes in condensed phases to be studied in an accurate and unbiased way. This article is intended to present the basics of the AIMD method as well as to provide a broad survey of the state of the art of the field and showcase some of its capabilities. Beginning with a derivation of the method from the Born-Oppenheimer approximation, issues including the density functional representation of electronic structure, basis sets, calculation of observables and the Car-Parrinello extended Lagrangian algorithm are discussed. A number of example applications, including liquid structure and dynamics and aqueous proton transport, are presented in order to highlight some of the current capabilities of the approach. Finally, advanced topics such as inclusion of nuclear quantum effects, excited states and scaling issues are addressed. (topical review)

  7. Unitary transformations in solid state physics

    International Nuclear Information System (INIS)

    Wagner, M.

    1986-01-01

    The main emphasis of this book is on the practical application of unitary transformations to problems in solid state physics. This is a method used in the field of nonadiabatic electron-phonon phenomena where the Born-Oppenheimer approximation is no longer applicable. The book is intended as a tool for those who want to apply unitary transformations quickly and on a more elementary level and also for those who want to use this method for more involved problems. The book is divided into 6 chapters. The first three chapters are concerned with presenting quick applications of unitary transformations and chapter 4 presents a more systematic procedure. The last two chapters contain the major known examples of the utilization of unitary transformations in solid state physics, including such highlights as the Froehlich and the Fulton-Gouterman transformations. The book is supplemented by extended tables of unitary transformations, whose properties and peculiarities are also listed. This tabulated material is unique and will be of great practical use to those applying the method of unitary transformations in their work. (Auth.)

  8. Joint M3 and Diviner Analysis of the Mineralogy, Glass Composition, and Country Rock Content of Pyroclastic Deposits in Oppenheimer Crater

    Science.gov (United States)

    Bennett, Kristen A.; Horgan, Briony H. N.; Greenhagen, Benjamin T.; Allen, Carlton C.; Paige, David A.; Bell, James F., III

    2013-01-01

    Here we present our analysis of the near- and mid-infrared spectral properties of pyroclastic deposits within the floor fractured Oppenheimer Crater that are hypothesized to be Vulcanian in origin. These are the first results of our global study of lunar pyroclastic deposits aimed at constraining the range of eruption processes on the Moon. In the near-infrared, we have employed a new method of spectral analysis developed in Horgan et al. (2013) of the 1 ?m iron absorption band in Chandrayaan-1 Moon Mineralogy Mapper (M3) spectra. By analyzing both the position and shape of the 1 ?m band we can detect and map the distribution of minerals, glasses, and mixtures of these phases in pyroclastic deposits. We are also using mid-infrared spectra from the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment to develop 200 m/pixel Christiansen Feature (CF) maps, which correlate with silica abundance. One of the benefits of using CF maps for analysis of pyroclastic deposits is that they can be used to detect silicic country rock that may have been emplaced by Vulcanian-style eruptions, and are sensitive to iron abundance in glasses, neither of which is possible in the near-infrared. M3 analysis reveals that the primary spectral endmembers are low-calcium pyroxene and iron-bearing glass, with only minor high-calcium pyroxene, and no detectable olivine. The large deposit in the south shows higher and more extensive glass concentrations than the surrounding deposits. We interpret the M3 spectra of the pyroclastic deposits as indicating a mixture of low-calcium pyroxene country rock and juvenile glass, and no significant olivine. Analysis of Diviner CF maps of the Oppenheimer crater floor indicates an average CF value of 8.16, consistent with a mixture of primarily plagioclase and some pyroxene. The average CF values of the pyroclastic deposits range from 8.31 in the SW to 8.24 in the SE. Since CF values within the deposits are as high as 8.49, the lower average CF

  9. HIV and sexual health knowledge and sexual experience among Australian-born and overseas-born students in Sydney.

    Science.gov (United States)

    Song, Angela; Richters, Juliet; Crawford, June; Kippax, Sue

    2005-09-01

    To examine differences between Australian-born and Asian-born first-year university students in Sydney in their sexual behavior and knowledge about the prevention and transmission of human immunodeficiency virus (HIV) and other sexually transmissible infections (STIs). Students were recruited from a stall during the student Orientation Week in both 2002 and 2003 at the University of New South Wales. A short questionnaire was completed and returned anonymously. Data on age, gender, country of birth, sexual behavior, and sexual health knowledge were collected. A score was calculated based on the sum of the correct answers given to 12 HIV/STI transmission and prevention questions. The students were then divided into three groups according to their country of birth (Australia, Asia, and elsewhere) and their knowledge scores were compared. Students born in certain Asian countries were also asked their perception of the HIV epidemic in their home country compared with Australia. A total of 1185 first-year students completed the questionnaire. Although older on average, Asian-born students were less likely to have had sexual intercourse and had had fewer sexual partners. They also had consistently poorer HIV/STI knowledge scores than Australian-born students. Students born in China, Hong Kong, Indonesia, Malaysia, and Singapore but not Thailand underestimated the prevalence of HIV in their country of birth in comparison with Australia. The combination of poorer knowledge, apparent misconception of the extent of HIV epidemic in their home country (or Australia), and potential later frequent travel indicates a potential risk for later transmission of HIV/STIs. The university is an underused setting for prevention health education.

  10. MijnBorne2030: evaluatie van een democratisch experiment

    NARCIS (Netherlands)

    Denters, Sebastianus A.H.; Klok, Pieter J.

    2015-01-01

    This article is about one of the experiments in local democratic renewal: MyBorne2030 (in Dutch ‘MijnBorne2030’). The aim of the project was to develop a communal vision for Borne (a relatively small suburban municipality of 20.000 inhabitants in the East of the Netherlands) for the year 2030. A

  11. A born dreamer

    Indian Academy of Sciences (India)

    Lawrence

    encouraged me to believe that education was the only way to fulfil one's dreams ... liant student, financial constraints prevented him from pursuing. A born ... higher education. .... to fulfil one's dream despite difficulties, which women face. How-.

  12. On the nucleon-nucleon potential obtained from non-linear coupling

    International Nuclear Information System (INIS)

    El Ghabaty, S.S.

    1975-07-01

    The static limit of a pseudoscalar symmetric meson theory of nuclear forces is examined. The Born-Oppenheimer potential is determined for the case of two very heavy nucleons exchanging pseudoscalar isovector pions with non-linear coupling. It is found that the non-linear terms induced by the γ 5 coupling are cancelled by the additional pion-nucleon coupling of the non-linear sigma model. The nucleon-nucleon potential thus obtained is the same as the Yukava potential except for strength at different separations between the two nucleons

  13. Emerging Vector-Borne Diseases - Incidence through Vectors.

    Science.gov (United States)

    Savić, Sara; Vidić, Branka; Grgić, Zivoslav; Potkonjak, Aleksandar; Spasojevic, Ljubica

    2014-01-01

    Vector-borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowadays, in intercontinental countries, there is a struggle with emerging diseases, which have found their way to appear through vectors. Vector-borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens, and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector-borne infectious diseases and disease outbreaks. It could affect the range and population of pathogens, host and vectors, transmission season, etc. Reliable surveillance for diseases that are most likely to emerge is required. Canine vector-borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, ehrlichiosis, and leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fundamental role at primarily prevention and then treatment of vector-borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases. During a 4-year period, from 2009 to 2013, a total number of 551 dog samples were analyzed for vector-borne diseases (borreliosis, babesiosis, ehrlichiosis, anaplasmosis, dirofilariosis, and leishmaniasis) in routine laboratory work. The analysis was done by serological tests - ELISA for borreliosis, dirofilariosis, and leishmaniasis, modified Knott test for dirofilariosis, and blood smear for babesiosis, ehrlichiosis, and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on average more then half of the samples

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

    Science.gov (United States)

    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.

  15. HIV Transmission Dynamics Among Foreign-Born Persons in the United States.

    Science.gov (United States)

    Valverde, Eduardo E; Oster, Alexandra M; Xu, Songli; Wertheim, Joel O; Hernandez, Angela L

    2017-12-15

    In the United States (US), foreign-born persons are disproportionately affected by HIV and differ epidemiologically from US-born persons with diagnosed HIV infection. Understanding HIV transmission dynamics among foreign-born persons is important to guide HIV prevention efforts for these populations. We conducted molecular transmission network analysis to describe HIV transmission dynamics among foreign-born persons with diagnosed HIV. Using HIV-1 polymerase nucleotide sequences reported to the US National HIV Surveillance System for persons with diagnosed HIV infection during 2001-2013, we constructed a genetic distance-based transmission network using HIV-TRACE and examined the birth region of potential transmission partners in this network. Of 77,686 people, 12,064 (16%) were foreign born. Overall, 28% of foreign-born persons linked to at least one other person in the transmission network. Of potential transmission partners, 62% were born in the United States, 31% were born in the same region as the foreign-born person, and 7% were born in another region of the world. Most transmission partners of male foreign-born persons (63%) were born in the United States, whereas most transmission partners of female foreign-borns (57%) were born in their same world region. These finding suggests that a majority of HIV infections among foreign-born persons in our network occurred after immigrating to the United States. Efforts to prevent HIV infection among foreign-born persons in the United States should include information of the transmission networks in which these individuals acquire or transmit HIV to develop more targeted HIV prevention interventions.

  16. Emerging Vector-Borne Diseases.

    Science.gov (United States)

    Huntington, Mark K; Allison, Jay; Nair, Dilip

    2016-10-01

    Several mosquito-borne viral infections have recently emerged in North America; West Nile virus is the most common in the United States. Although West Nile virus generally causes a self-limited, flulike febrile illness, a serious neuroinvasive form may occur. Dengue is the most common vector-borne viral disease worldwide, and it has been a significant public health threat in the United States since 2009. Known as breakbone fever for its severe myalgias and arthralgias, dengue may cause a hemorrhagic syndrome. Chikungunya also causes flulike febrile illness and disabling arthralgias. Although meningoencephalitis may occur with chikungunya, bleeding is uncommon. Symptoms of Zika virus infection are similar to those of dengue, but milder. Zika virus increases the risk of fetal brain abnormalities, including microcephaly, if a pregnant woman is infected. Zika virus is spread through Aedes albopictus mosquito bites, is transmitted sexually, and may rarely spread nonsexually from person to person. Diagnosis of these vectorborne infections is clinical and serologic, and treatment is supportive. Other, well-established vector-borne diseases are also important. Ehrlichiosis is a tick-borne bacterial disease that presents as a nonspecific syndrome of fever, headache, malaise, and myalgias. It is diagnosed via blood smear testing, with confirmatory serology. Ehrlichiosis is treated with doxycycline. Rickettsial infections are transmitted by fleas, mites, and ticks, and severity ranges from mild to life threatening. Rocky Mountain spotted fever, the most significant rickettsial infection, is primarily a clinical diagnosis that presents as fever, headache, myalgias, petechial rash, and tick exposure. Doxycycline is effective for rickettsial infections if administered promptly. Vector avoidance strategies are critical to the prevention of all of these infections.

  17. Allostatic load in foreign-born and US-born blacks: evidence from the 2001-2010 National Health and Nutrition Examination Survey.

    Science.gov (United States)

    Doamekpor, Lauren A; Dinwiddie, Gniesha Y

    2015-03-01

    We tested whether the immigrant health advantage applies to non-Hispanic Black immigrants and examined whether nativity-based differences in allostatic load exist among non-Hispanic Blacks. We used pooled data from the 2001-2010 National Health and Nutrition Examination Survey to compare allostatic load scores for US-born (n = 2745) and foreign-born (n = 152) Black adults. We used multivariate logistic regression techniques to assess the association between nativity and high allostatic load scores, controlling for gender, age, health behaviors, and socioeconomic status. For foreign-born Blacks, length of stay and age were powerful predictors of allostatic load scores. For older US-born Blacks and those who were widowed, divorced, or separated, the risk of high allostatic load was greater. Foreign-born Blacks have a health advantage in allostatic load. Further research is needed that underscores a deeper understanding of the mechanisms driving this health differential to create programs that target these populations differently.

  18. Electronic structure, Born effective charges and spontaneous polarization in magnetoelectric gallium ferrite

    International Nuclear Information System (INIS)

    Roy, Amritendu; Garg, Ashish; Mukherjee, Somdutta; Gupta, Rajeev; Prasad, Rajendra; Auluck, Sushil

    2011-01-01

    We present a theoretical study of the structure-property correlation in gallium ferrite, based on first-principles calculations followed by a subsequent comparison with experiments. The local spin density approximation (LSDA + U) of the density functional theory has been used to calculate the ground state structure, electronic band structure, density of states and Born effective charges. The calculations reveal that the ground state structure is orthorhombic Pc 2 1 n having A-type antiferromagnetic spin configuration, with lattice parameters matching well with those obtained experimentally. Plots of the partial density of states of constituent ions exhibit noticeable hybridization of Fe 3d, Ga 4s, Ga 4p and O 2p states. However, the calculated charge density and electron localization function show a largely ionic character of the Ga/Fe-O bonds which is also supported by a lack of any significant anomaly in the calculated Born effective charges with respect to the corresponding nominal ionic charges. The calculations show a spontaneous polarization of ∼ 59 μC cm -2 along the b-axis which is largely due to asymmetrically placed Ga1, Fe1, O1, O2 and O6 ions.

  19. Ventilatory Efficiency in Children and Adolescents Born Extremely Preterm

    Directory of Open Access Journals (Sweden)

    Julie Hestnes

    2017-07-01

    Full Text Available Purpose: Children and adolescents born extremely preterm (EP have lower dynamic lung volumes and gas transfer capacity than subjects born at term. Most studies also report lower aerobic capacity. We hypothesized that ventilatory efficiency was poorer and that breathing patterns differed in EP−born compared to term−born individuals.Methods: Two area−based cohorts of participants born with gestational age ≤28 weeks or birth weight ≤1000 g in 1982−85 (n = 46 and 1991–92 (n = 35 were compared with individually matched controls born at term. Mean ages were 18 and 10 years, respectively. The participants performed an incremental treadmill exercise test to peak oxygen uptake with data averaged over 20 s intervals. For each participant, the relationship between exhaled minute ventilation (V˙E and carbon dioxide output (V˙CO2 was described by a linear model, and the relationship between tidal volume (VT and V˙E by a quadratic model. Multivariate regression analyses were done with curve parameters as dependent variables, and the categories EP vs. term−born, sex, age, height, weight and forced expiratory volume in 1 s (FEV1 as independent variables.Results: In adjusted analyses, the slope of the V˙E−V˙CO2 relationship was significantly steeper in the EP than the term-born group, whereas no group difference was observed for the breathing pattern, which was related to FEV1 only.Conclusion: EP-born participants breathed with higher V˙E for any given CO2 output, indicating lower ventilatory efficiency, possibly contributing to lower aerobic capacity. The breathing patterns did not differ between the EP and term−born groups when adjusted for FEV1.

  20. Quality of Cancer Care Among Foreign-Born and US-Born Patients With Lung or Colorectal Cancer

    DEFF Research Database (Denmark)

    Nielsen, Signe Smith; He, Yulei; Ayanian, John Z.

    2010-01-01

      BACKGROUND: Disparities in care have been documented for foreign-born cancer patients in the United States. However, few data are available regarding patients with lung and colorectal cancer. In the current study, the authors assessed whether patient-reported quality and receipt of recommended...... from 2003 through 2005. Logistic regression was used to assess the association between nativity and patient-reported quality of care and receipt of recommended treatments (adjuvant chemotherapy for stage III colon cancer, adjuvant chemotherapy and radiotherapy for stage II/III rectal cancer......, and curative surgery for stage I/II non-small cell lung cancer). The authors also assessed whether language explained any differences in care by nativity. RESULTS: Overall, 46% of patients reported excellent care, but foreign-born patients were less likely than US-born patients to report excellent quality...

  1. Hierarchical low-rank approximation for high dimensional approximation

    KAUST Repository

    Nouy, Anthony

    2016-01-07

    Tensor methods are among the most prominent tools for the numerical solution of high-dimensional problems where functions of multiple variables have to be approximated. Such high-dimensional approximation problems naturally arise in stochastic analysis and uncertainty quantification. In many practical situations, the approximation of high-dimensional functions is made computationally tractable by using rank-structured approximations. In this talk, we present algorithms for the approximation in hierarchical tensor format using statistical methods. Sparse representations in a given tensor format are obtained with adaptive or convex relaxation methods, with a selection of parameters using crossvalidation methods.

  2. Hierarchical low-rank approximation for high dimensional approximation

    KAUST Repository

    Nouy, Anthony

    2016-01-01

    Tensor methods are among the most prominent tools for the numerical solution of high-dimensional problems where functions of multiple variables have to be approximated. Such high-dimensional approximation problems naturally arise in stochastic analysis and uncertainty quantification. In many practical situations, the approximation of high-dimensional functions is made computationally tractable by using rank-structured approximations. In this talk, we present algorithms for the approximation in hierarchical tensor format using statistical methods. Sparse representations in a given tensor format are obtained with adaptive or convex relaxation methods, with a selection of parameters using crossvalidation methods.

  3. Atopic diseases in twins born after assisted reproduction

    DEFF Research Database (Denmark)

    Jäderberg, Ida; Thomsen, Simon F; Kyvik, Kirsten Ohm

    2012-01-01

    Jäderberg I, Thomsen SF, Kyvik KO, Skytthe A, Backer V. Atopic diseases in twins born after assisted reproduction. Paediatric and Perinatal Epidemiology 2012; 26: 140-145. We examined the risk of atopic diseases in twins born after assisted reproduction. Data on atopic diseases and assisted...... reproduction in 9694 twin pairs, 3-20 years of age, from the Danish Twin Registry were collected via multidisciplinary questionnaires. The risk of atopic diseases in twins born after assisted reproduction was compared with the risk in twins born after spontaneous conception using logistic regression...... and variance components analysis. Children born after assisted reproduction did not have a different risk of atopic outcomes (adjusted odds ratios [95% confidence intervals] for asthma: 0.95 [0.85, 1.07], P = 0.403; hay fever: 1.01 [0.86, 1.18], P = 0.918; and atopic dermatitis: 1.02 [0.81, 1.11], P = 0...

  4. Equine tick-borne infections in the Netherlands

    NARCIS (Netherlands)

    Butler, C.M.

    2012-01-01

    This thesis focuses on the emergence and establishment of equine tick-borne infections in the Netherlands, with particular attention to their diagnosis, clinical relevance and treatment. Four tick-borne agents (Borrelia burgdorferi, Theileria equi, Babesia caballi and Anaplasma phagocytophilum)

  5. Bacterial food-borne zoonoses.

    Science.gov (United States)

    Thorns, C J

    2000-04-01

    In many countries of the world, bacterial food-borne zoonotic infections are the most common cause of human intestinal disease. Salmonella and Campylobacter account for over 90% of all reported cases of bacteria-related food poisoning world-wide. Poultry and poultry products have been incriminated in the majority of traceable food-borne illnesses caused by these bacteria, although all domestic livestock are reservoirs of infection. In contrast to the enzootic nature of most Salmonella and Campylobacter infections, Salmonella Enteritidis caused a pandemic in both poultry and humans during the latter half of the 20th Century. Salmonella Typhimurium and Campylobacter appear to be more ubiquitous in the environment, colonising a greater variety of hosts and environmental niches. Verocytotoxin-producing Escherichia coli O157 (VTEC O157) also emerged as a major food-borne zoonotic pathogen in the 1980s and 1990s. Although infection is relatively rare in humans, clinical disease is often severe, with a significant mortality rate among the young and elderly. The epidemiology of VTEC O157 is poorly understood, although ruminants, especially cattle and sheep, appear to be the major source of infection. The dissemination of S. Enteritidis along the food chain is fairly well understood, and control programmes have been developed to target key areas of poultry meat and egg production. Recent evidence indicates that these control programmes have been associated with an overall reduction of S. Enteritidis along the food chain. Unfortunately, existing controls do not appear to reduce the levels of Campylobacter and VTEC O157 infections. Future control strategies need to consider variations in the epidemiologies of food-borne zoonotic infections, and apply a quantitative risk analysis approach to ensure that the most cost-effective programmes are developed.

  6. [Conflicts and vector-borne diseases

    DEFF Research Database (Denmark)

    Bygbjerg, Ib Christian

    2010-01-01

    Based on literature and personal experiences, vector-borne diseases and conflicts are reviewed. Simple rapid diagnostic tests for three important parasitoses are available. Resort is often made to case definitions and to presumptive treatment. Resistance is an emerging problem. Vaccines are still...... not available for most diseases. Promising preventive methods, including long-lasting impregnated bed-nets and tents, are available. War has been an impetus for disclosing life-cycles of vector-borne diseases and for control methods; peace, reconciliation and poverty reduction are required to achieve lasting...

  7. Pap Tests and Foreign-Born Women

    Centers for Disease Control (CDC) Podcasts

    Foreign-born women living in the U.S. are less likely to have Pap tests to detect cervical cancer than women born in this country. The problem is worse for women from certain countries or regions. Find out why this is a disturbing trend, who these women are and why they are less likely to get a Pap test, and what CDC is doing about it.

  8. Neurocognitive outcome in young adults born late-preterm.

    Science.gov (United States)

    Heinonen, Kati; Lahti, Jari; Sammallahti, Sara; Wolke, Dieter; Lano, Aulikki; Andersson, Sture; Pesonen, Anu-Katriina; Eriksson, Johan G; Kajantie, Eero; Raikkonen, Katri

    2018-03-01

    This study examined whether late-preterm birth (34+0 to 36+6wks+d gestational age) was associated with neurocognitive deficit in young adulthood, and whether small for gestational age (SGA) birth amplified any adversity. Participants derived from the prospective regional cohort study, the Arvo Ylppö Longitudinal Study (n=786; 398 females, 388 males) (mean age 25y 4mo, SD 8mo), born 1985 to 1986 late-preterm (n=119; 21 SGA, intelligence, executive functioning, attention, and memory, and reported their education. Those born late-preterm scored -3.71 (95% confidence interval [CI] -6.71 to -0.72) and -3.11 (95% CI -6.01 to -0.22) points lower on Full-scale and Verbal IQ than peers born at term. Compared with those born at term and appropriate for gestational age (≥-2 to increase the risk of poorer neurocognitive functioning in adulthood. But the double burden of being born late-preterm and SGA seems to increase this risk. Late-preterm birth did not increase the risk of poorer neurocognitive functioning in adulthood. But the double burden of being born late-preterm and being small for gestational age did increase this risk. © 2017 Mac Keith Press.

  9. The birth of CERN

    CERN Multimedia

    Parkins, David

    2017-01-01

    At an intergovernmental meeting of UNESCO in Paris in December 1951, the first resolution concerning the establishment of a European Council for Nuclear Research was adopted. Two months later, 11 countries signed an agreement establishing the provisional council – the acronym CERN was born. This humoristic drawing features some of the main characters who were involved in the establishment of CERN. On the American hen: Isidor Rabi and Robert Oppenheimer, while on the hatching egg we recognize Francis Perrin (France), Niels Bohr (Denmark), Werner Heisenberg (Germany) and Sir George Paget Thomson (United Kingdom).

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

    Science.gov (United States)

    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.

  11. Tornado-borne missile speeds. Final report

    International Nuclear Information System (INIS)

    Simiu, E.; Cordes, M.

    1976-04-01

    An investigation of the question of tornado-borne missile speeds was carried out, with a view to identify pertinent areas of uncertainty and to estimate credible tornado-borne missile speeds - within the limitations inherent in the present state of the art. The investigation consists of two parts: (1) a study in which a rational model for the missile motion is proposed, and numerical experiments are carried out corresponding to various assumptions on the initial conditions of the missile motion, the structure of the tornado flow, and the aerodynamic properties of the missile; (2) a theoretical and experimental study of tornado-borne missile aerodynamics, conducted by Colorado State Univ. (CSU) to be covered in a separate report by CSU. In the present report, the factors affecting missile motion and their influence upon such motion are examined

  12. Dual symmetry in Born-Infeld theory

    International Nuclear Information System (INIS)

    Khademi, S; Ayoubi, A

    2008-01-01

    Born-Infeld theory is a non-linear formalism which has many applications in string and electromagnetic theories. Although, the existence of magnetic monopoles and dyons are suggested by Born-Infeld theory, but this theory is not invariant under the dual transformations. In this theory electric fields for point charged particles are not singular at origin (r = 0), but magnetic fields and vector potentials are still singular. In this paper we show that the vanishing of dual symmetry is responsible for these singularities. Furthermore, we present the dual symmetric Born-Infeld theory, by a symmetric definition of electromagnetic fields in terms of new scalar and vector potentials, as well as the ordinary ones. All singularities of vector potential and magnetic field are removed as an immediate consequence of this symmetry.

  13. Impact of Neighborhood Environments on Health Consciousness, Information Seeking, and Attitudes among US-Born and Non-US-Born Free Clinic Patients.

    Science.gov (United States)

    Kamimura, Akiko; Ashby, Jeanie; Jess, Allison; Trinh, Ha Ngoc; Nourian, Maziar M; Finlayson, Sarah Yukie; Prudencio, Liana; Reel, Justine J

    2015-12-01

    This study examined the impact of neighborhood environments on health consciousness, information seeking, and attitudes among uninsured free clinic patients to better understand the specific needs of the population for health promotion and prevention efforts. US-born English-speaking, non-US-born English-speaking, and Spanish-speaking free clinic patients completed a self-administered survey using reliable measures in autumn 2014 (N = 769). The results of this study suggest that social cohesion is positively associated with health consciousness, information seeking, and attitudes. Lower levels of available healthy food in the community were associated with higher levels of health consciousness. Although Spanish speakers reported lower levels of the availability of healthy food, social cohesion, and access to the Internet or text messaging compared with US-born or non-US-born English speakers, they were more likely to be health conscious and have higher levels of health information seeking. Spanish speakers as well as non-US-born English speakers, were more likely to attend health education classes compared with US-born English speakers. Health education programs for free clinic patients should include strategies to increase social cohesion. Health education programs should consider the diverse needs of these individual populations to maximize the effectiveness of the programs for free clinic patients.

  14. Behavioural skills in 7 year old children born post-term

    DEFF Research Database (Denmark)

    Olesen, Annette Wind; Olsen, Jørn; Zhu, Jin Liang

    2014-01-01

    Abstract Objective: To study behavioural skills at the age of seven in a Danish population of children born post-term. Design: Cohort study. Setting: The Danish National Birth Cohort; children born from 1997 to 2003. Population: Data was obtained from a cohort of about 100,000 women...... and their children. All singletons born in gestational week 39-45 were identified, and then restricted to children whose mothers filled out a Strength and Difficulties Questionnaire (STQ) when they were seven years of age. The study population constituted 33842 singletons (21249 born at term and 12593 born post...

  15. Atopic diseases in twins born after assisted reproduction.

    Science.gov (United States)

    Jäderberg, Ida; Thomsen, Simon F; Kyvik, Kirsten O; Skytthe, Axel; Backer, Vibeke

    2012-03-01

    We examined the risk of atopic diseases in twins born after assisted reproduction. Data on atopic diseases and assisted reproduction in 9694 twin pairs, 3-20 years of age, from the Danish Twin Registry were collected via multidisciplinary questionnaires. The risk of atopic diseases in twins born after assisted reproduction was compared with the risk in twins born after spontaneous conception using logistic regression and variance components analysis. Children born after assisted reproduction did not have a different risk of atopic outcomes (adjusted odds ratios [95% confidence intervals] for asthma: 0.95 [0.85, 1.07], P = 0.403; hay fever: 1.01 [0.86, 1.18], P = 0.918; and atopic dermatitis: 1.02 [0.81, 1.11], P = 0.773 respectively) compared with children born after spontaneous conception. Assisted reproduction did not modify the heritability of atopic diseases. This study does not support an association between assisted reproduction and development of atopic diseases. This result must be confirmed in subsequent studies, preferably of singleton populations. © 2011 Blackwell Publishing Ltd.

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

    Science.gov (United States)

    Bae, Sung-Heui

    2017-10-01

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

  17. Refractive index in generalized superconductors with Born-Infeld electrodynamics

    Science.gov (United States)

    Cheng, Jun; Pan, Qiyuan; Yu, Hongwei; Jing, Jiliang

    2018-03-01

    We investigate, in the probe limit, the negative refraction in the generalized superconductors with the Born-Infeld electrodynamics. We observe that the system has a negative Depine-Lakhtakia index in the superconducting phase at small frequencies and the greater the Born-Infeld corrections the larger the range of frequencies or the range of temperatures for which the negative refraction occurs. Furthermore, we find that the tunable Born-Infeld parameter can be used to improve the propagation of light in the holographic setup. Our analysis indicates that the Born-Infeld electrodynamics plays an important role in determining the optical properties of the boundary theory.

  18. Recharging of a screened ion on the molecular ion

    International Nuclear Information System (INIS)

    Karbovanets, M.I.; Lazur, V.Yu.; Yudin, G.L.; Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Obninsk. Fiziko-Ehnergeticheskij Inst.)

    1987-01-01

    Charge exchange of a screened ion on a molecular ion is studied in the Oppenheimer-Brinkman-Cramers approximation. To calculate ion exchange probabilities and cross sections summed over the final degenerated electron states method of Green functions analogous to that applied earlier in the direct Coulomb excitation theory and atomic ionization is developed

  19. Vector-borne Infections

    Centers for Disease Control (CDC) Podcasts

    2011-04-18

    This podcast discusses emerging vector-borne pathogens, their role as prominent contributors to emerging infectious diseases, how they're spread, and the ineffectiveness of mosquito control methods.  Created: 4/18/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID).   Date Released: 4/27/2011.

  20. Tick-borne encephalitis: Pathogenesis and clinical implications

    Czech Academy of Sciences Publication Activity Database

    Růžek, Daniel; Dobler, G.; Mantke, O. D.

    2010-01-01

    Roč. 8, č. 4 (2010), s. 223-232 ISSN 1477-8939 R&D Projects: GA ČR GPP302/10/P438; GA MŠk(CZ) LC06009 Institutional research plan: CEZ:AV0Z60220518 Keywords : Tick-borne encephalitis * Tick-borne encephalitis virus * Pathogenesis * Clinical data Subject RIV: EE - Microbiology, Virology

  1. Internalized racism and mental health among African-Americans, US-born Caribbean Blacks, and foreign-born Caribbean Blacks.

    Science.gov (United States)

    Mouzon, Dawne M; McLean, Jamila S

    2017-02-01

    The tripartite model of racism includes personally mediated racism, institutionalized racism, and the less-oft studied internalized racism. Internalized racism - or negative beliefs about one's racial group - results from cultural racism that is endemic in American society. In this project, we studied whether these negative stereotypes are associated with mental health among African-Americans and Caribbean Blacks. Using secondary data from the National Survey of American Life, we investigated the association between internalized racism and mental health (measured by depressive symptoms and serious psychological distress (SPD)) among these two groups. We also explored whether ethnicity/nativity and mastery moderate the association between internalized racism and mental health among African-Americans and Caribbean Blacks. Internalized racism was positively associated with depressive symptoms and SPD among all Black subgroups. However, internalized racism was a weaker predictor of SPD among foreign-born Caribbean Blacks than US-born Caribbean Blacks and US-born African-Americans. Additionally, higher mastery was protective against distress associated with internalized racism. Internalized racism is an important yet understudied determinant of mental health among Blacks. Future studies should take into account additional heterogeneity within the Black population (e.g. African-born individuals) and other potential protective mechanisms in addition to mastery (e.g. self-esteem and racial identity).

  2. Management of soil-borne diseases of organic vegetables

    Directory of Open Access Journals (Sweden)

    Shafique Hafiza Asma

    2016-07-01

    Full Text Available With the rising awareness of the adverse effects of chemical pesticides, people are looking for organically grown vegetables. Consumers are increasingly choosing organic foods due to the perception that they are healthier than those conventionally grown. Vegetable crops are vulnerable to a range of pathogenic organisms that reduce yield by killing the plant or damaging the product, thus making it unmarketable. Soil-borne diseases are among the major factors contributing to low yields of organic produce. Apart from chemical pesticides there are several methods that can be used to protect crops from soil-borne pathogens. These include the introduction of biocontrol agents against soil-borne plant pathogens, plants with therapeutic effects and organic soil amendments that stimulate antagonistic activities of microorganisms to soil-borne diseases. The decomposition of organic matter in soil also results in the accumulation of specific compounds that may be antifungal or nematicidal. With the growing interest in organic vegetables, it is necessary to find non chemical means of plant disease control. This review describes the impact of soil-borne diseases on organic vegetables and methods used for their control.

  3. Obesity Among U.S.- and Foreign-Born Blacks by Region of Birth.

    Science.gov (United States)

    Mehta, Neil K; Elo, Irma T; Ford, Nicole D; Siegel, Karen R

    2015-08-01

    Large, recent migration streams from the non-Hispanic Caribbean islands and Africa have increased the share of U.S. blacks born outside of the U.S. Little is known about health patterns in these foreign-born populations. The purpose of this study is to compare obesity levels among self-identified U.S. blacks across birth regions and examine potential explanations for subgroup differences. Data were from the 2000-2013 National Health Interview Surveys. Three birthplace subgroups were examined: individuals born in the U.S., Caribbean/South America, and Africa, aged 25-59 years. Data were analyzed in 2013-2014. Compared to U.S.-born participants, foreign-born participants had significantly lower obesity (BMI ≥30) odds. The AORs were 0.51 (Caribbean/South American-born, 95% CI=0.44, 0.58) and 0.41 (African-born, 95% CI=0.34, 0.50) with reference to U.S.-born individuals. Education, income, and cigarette smoking did not explain the favorable weight pattern of the foreign born. Among the foreign born, those residing in the U.S. for ≥15 years had 51% (95% CI=10%, 108%) higher obesity odds compared with those residing for <5 years. No statistically significant differences in obesity odds between those born in the Caribbean/South America and Africa were detected. Foreign-born blacks generally had lower obesity levels compared to their U.S.-born counterparts, which was not explained by SES or smoking behaviors. Despite this advantage, obesity prevalence among foreign-born black women was around 30%, suggesting that obesity poses a significant health risk this population. Copyright © 2015 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  4. Typing and virulence factors of food-borne Candida spp. isolates.

    Science.gov (United States)

    Rajkowska, Katarzyna; Kunicka-Styczyńska, Alina

    2018-08-20

    Food-borne yeasts, excluding yeasts used as starter cultures, are commonly considered as food spoilage microorganisms. However, the incidence of non-C. albicans Candida (NCAC) infections has increased considerably over the past two decades. Although 15 Candida species are frequently identified as pathogens, a threat to human from food-borne Candida is poorly recognized. In the present study food-borne NCAC were characterized for the virulence factors, known to be associated with yeast pathogenicity. All food-borne strains in planktonic forms and 89% in biofilm structures represented biotypes established for C. albicans, and 61% demonstrated hemolytic activity. 56-94% of food-borne isolates formed biofilms on glass and biomaterials at a level comparable to clinical C. albicans. Nine out of eighteen tested food-borne NCAC strains (C. krusei, C. lusitaniae, C. famata, C. colliculosa, C. parapsilosis, C. tropicalis) showed similarity to clinical C. albicans in terms of their biotypes and the tested virulence factors, allocating them in a group of risk of potential pathogens. However, their capacity to grow at 37 °C seems to be the preliminary criterion in the study of potential virulence of food-borne yeasts. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Born-Infeld Nonlinear Electrodynamics

    International Nuclear Information System (INIS)

    Bialynicki-Birula, I.

    1999-01-01

    This is only a summary of a lecture delivered at the Infeld Centennial Meeting. In the lecture the history of the Born-Infeld nonlinear electrodynamics was presented and some general features of the theory were discussed. (author)

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

    Science.gov (United States)

    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…

  7. Obstetric and psychosocial risk factors for Australian-born and non-Australian born women and associated pregnancy and birth outcomes: a population based cohort study.

    Science.gov (United States)

    Dahlen, Hannah Grace; Barnett, Bryanne; Kohlhoff, Jane; Drum, Maya Elizabeth; Munoz, Ana Maria; Thornton, Charlene

    2015-11-09

    One in four Australians is born overseas and 47% are either born overseas or have a parent who was. Obstetric and psychosocial risk factors for these women may differ. Data from one Sydney hospital (2012-2013) of all births recorded in the ObstetriX database were analysed (n = 3,092). Demographics, obstetric and psychosocial risk profile, obstetric interventions and complications and selected maternal and neonatal outcomes were examined for women born in Australia and overseas. Women born in Australia were younger, more likely to be primiparous (28.6 v 27.5%), be obese (32.0% v 21.4%), smoke (19.7 % v 3.0%), have an epidural (26.2% v 20.2%) and were less likely to have gestational diabetes mellitus (GDM) (6.8% v 13.7% when compared to non-Australian born women. The highest rates of GDM, Gestational Hypertension (GH) and maternal anaemia were seen in women born in China, the Philippines and Pakistan respectively. Differences were also seen in psychosocial screening between Australian and non-Australian women with Australian-born women more likely to smoke and report a mental health disorder. There was an association between having an Edinburgh Postnatal Depression Scale (EPDS) ≥ 13 and other psychosocial issues, such as thoughts of self-harm, domestic violence, childhood abuse etc. These women were also less likely to breastfeed. Women with an EPDS ≥ 13 at booking compared to women with EPDS ≤12 had a higher chance of being diagnosed with GDM (AOR 1.85 95% CI 1.14-3.0). There are significant differences in obstetric and psychosocial risk profiles and maternal and neonatal outcomes between Australian-born and non-Australian born women. In particular there appears to be an association between an EPDS of ≥13 and developing GDM, which warrants further investigation.

  8. 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

    Science.gov (United States)

    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.

  9. Firms' degree of born-globalness, international entrepreneurial orientation and export performance

    DEFF Research Database (Denmark)

    Servais, Per; Kuivalainen, Olli; Sundqvist, Sanna

    2007-01-01

    Despite the recent increase in 'born-global' studies, there has been little research on how the scale and scope of being a born-global firm affects performance: most of the earlier research takes no account either the number of or the distances between the countries on firm or export performance...... born-global pathways. The results of our empirical study on 185 Finnish exporting firms show that those that qualified as true born-globals had better export performance. Furthermore, depending on the degree of born-globalness, different dimensions of EO were of importance....

  10. Suboptimal care and maternal mortality among foreign-born women in Sweden

    DEFF Research Database (Denmark)

    Esscher, Annika; Binder-Finnema, Pauline; Bødker, Birgit

    2014-01-01

    that occurred in Sweden from 1988-2010. METHODS: A subset of maternal death records (n = 75) among foreign-born women from low- and middle-income countries and Swedish-born women were audited using structured implicit review. One case of foreign-born maternal death was matched with two native born Swedish cases...... language and suboptimal interpreter system or usage. Inadequate care occurred more often among the foreign-born (p = 0.04), whereas delays in consultation/referral and miscommunication between health care providers where equally common between the two groups. CONCLUSIONS: Suboptimal care factors, major...

  11. We have "born digital" - now what about "born semantic"?

    Science.gov (United States)

    Leadbetter, Adam; Fredericks, Janet

    2014-05-01

    The phrase "born-digital" refers to those materials which originate in a digital form. In Earth and Space Sciences, this is now very much the norm for data: analogue to digital converters sit on instrument boards and produce a digital record of the observed environment. While much effort has been put in to creating and curating these digital data, there has been little work on using semantic mark up of data from the point of collection - what we term 'born semantic'. In this presentation we report on two efforts to expand this area: Qartod-to-OGC (Q2O) and SenseOCEAN. These projects have taken a common approach to 'born semantic': create or reuse appropriate controlled vocabularies, published to World Wide Web Commission (W3C) standards use standards from the Open Geospatial Consortium's Sensor Web Enablement (SWE) initiative to describe instrument setup, deployment and/or outputs using terms from those controlled vocabularies embed URLs from the controlled vocabularies within the SWE documents in a "Linked Data" conformant approach Q2O developed best practices examples of SensorML descriptions of Original Equipment Manufacturers' metadata (model characteristics, capabilities, manufacturer contact, etc ...) set-up and deployment SensorML files; and data centre process-lineage using registered vocabularies to describe terms (including input, output, processes, parameters, quality control flags) One Q2O use case, the Martha's Vineyard Coastal Observatory ADCP Waves instance, uses SensorML and registered vocabularies to fully describe the process of computing wave parameters from sensed properties, including quality control tests and associated results. The European Commission Framework Programme 7 project SenseOCEAN draws together world leading marine sensor developers to create a highly integrated multifunction and cost-effective in situ marine biogeochemical sensor system. This project will provide a quantum leap in the ability to measure crucial biogeochemical

  12. Computer simulations for the nano-scale

    International Nuclear Information System (INIS)

    Stich, I.

    2007-01-01

    A review of methods for computations for the nano-scale is presented. The paper should provide a convenient starting point into computations for the nano-scale as well as a more in depth presentation for those already working in the field of atomic/molecular-scale modeling. The argument is divided in chapters covering the methods for description of the (i) electrons, (ii) ions, and (iii) techniques for efficient solving of the underlying equations. A fairly broad view is taken covering the Hartree-Fock approximation, density functional techniques and quantum Monte-Carlo techniques for electrons. The customary quantum chemistry methods, such as post Hartree-Fock techniques, are only briefly mentioned. Description of both classical and quantum ions is presented. The techniques cover Ehrenfest, Born-Oppenheimer, and Car-Parrinello dynamics. The strong and weak points of both principal and technical nature are analyzed. In the second part we introduce a number of applications to demonstrate the different approximations and techniques introduced in the first part. They cover a wide range of applications such as non-simple liquids, surfaces, molecule-surface interactions, applications in nano technology, etc. These more in depth presentations, while certainly not exhaustive, should provide information on technical aspects of the simulations, typical parameters used, and ways of analysis of the huge amounts of data generated in these large-scale supercomputer simulations. (author)

  13. Preschool abilities of children born preterm and low weight

    Directory of Open Access Journals (Sweden)

    Sasha A. Martínez-Espiet

    2018-10-01

    Full Text Available The purpose of this study was to evaluate the development among a group of pre-school children born premature and with low weight. We evaluated a group of four years old children; 20 children born prematurely and 20 children born after a full gestation and desired weight, using the Beery-Buktenica visual-motor integration test. We also administered the Ages and Stages Questionnaire (ASQ-3 development test to all 40 mothers. Statistical analysis was performed using student t test for independent groups. The group of children born prematurely scored significantly lower on tests measuring visual perception skills (µ1 83.65 ; µ2 93.7 (p = 0.0001, visual-motor integration (µ1 93.6 ; µ2 104.8 (p = 0.001 and fine motor (µ1 36.00 ; µ2 44.25 (p=0.033 (p = 0.033, when compared to the group of children born after a full term. This study suggests that premature low weight born children have lower performance in the sensory-motor development during the preschool years. These disadvantages go unnoticed and may represent future delays on school tasks that require these skills. It is important to promote an early assessment and environmental stimulation among this population even in the absence of risk indicators.

  14. Increased risk of peanut allergy in infants of Asian-born parents compared to those of Australian-born parents.

    Science.gov (United States)

    Koplin, J J; Peters, R L; Ponsonby, A-L; Gurrin, L C; Hill, D; Tang, M L K; Dharmage, S C; Allen, K J

    2014-12-01

    Asian infants appear to be over-represented among patients with clinical food allergy in Australia, but this has not been formally examined at the population level. Any difference in prevalence according to parental country of birth may be secondary to modifiable lifestyle factors. We aimed to quantify (i) differences in the prevalence of peanut allergy by parental country of birth and (ii) contribution of measured environmental exposures to these differences. The population-based HealthNuts study in Melbourne, Australia, screened 5276 infants (74% participation) with skin prick tests and sensitized infants underwent food challenge. Of these, 535 had a parent born in East Asia and 574 in UK/Europe. Associations between parents' country of birth and offspring peanut allergy were examined using multiple logistic regression. Compared to infants with two Australian-born parents, peanut allergy was more common among infants with parent/s born in East Asia (OR 3.4, 95% CI 2.2-5.1) but not those with parent/s born in the UK/Europe (OR 0.8, 95% CI 0.4-1.5). Paradoxically rates of allergic disease were lower among Asian parents. A higher prevalence of eczema among infants of Asian parents explained around 30% of the increase in peanut allergy, while differences in dog ownership explained around 18%. The high peanut allergy prevalence among infants of Asian-born parents appears to have occurred in a single generation and was not present among infants with parents migrating from other countries, suggesting gene-environment interactions are important. The role of eczema and microbial exposure in food allergy prevention warrants exploration. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Joint Laxity in Preschool Children Born Preterm.

    Science.gov (United States)

    Romeo, Domenico M; Velli, Chiara; Lucibello, Simona; Ferrantini, Gloria; Leo, Giuseppina; Brogna, Claudia; Cota, Francesco; Ricci, Daniela; Gallini, Francesca; Romagnoli, Costantino; Vento, Giovanni; Mercuri, Eugenio

    2018-06-01

    To evaluate the prevalence of joint laxity in children born preterm assessed in the first 2 years, the relationship between joint laxity and motor performance at preschool age, and possible changes over time in a subgroup of children followed longitudinally. The revised scale of Beighton Score was used to evaluate joint laxity in a population of 132 preschool children born preterm between 24 and 32 weeks of gestational age. All were assessed for joint laxity between 12 and 24 months of age. Children also performed the Movement Assessment Battery for Children-Second Edition between the age of 3 years and 6 months and 4 years; the age at onset of independent walking also was recorded. The total Beighton Score ranged between 0 and 8. Twenty percent of the cohort showed joint laxity. No differences related to sex or gestational age were observed. Children born preterm with joint laxity achieved later independent walking and achieved lower scores on Movement Assessment Battery for Children-Second Edition than those without joint laxity. In 76 children born preterm, an assessment for joint laxity was repeated once between 25 and 36 months and again after >36 months. No statistically significant difference was observed between the 3 assessments. The Beighton Score can be used to assess generalized joint laxity in children born preterm. As the presence of joint laxity influenced motor competences, the possibility to early identify these infants in the first 2 years is of interest to benefit from early intervention and potentially improve gross motor skills and coordination. Copyright © 2018 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    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 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.

  17. Volumetric changes of the nose and nasal airway 2 years after tooth-borne and bone-borne surgically assisted rapid maxillary expansion

    NARCIS (Netherlands)

    Nada, R.M.; Loon, B. van; Schols, J.G.J.H.; Maal, T.J.J.; Koning, M.J.J. de; Mostafa, Y.A.; Kuijpers-Jagtman, A.M.

    2013-01-01

    This study aimed to assess the effects of bone-borne and tooth-borne surgically assisted rapid maxillary expansion on the volumes of the nose and nasal airway 2 yr after maxillary expansion. This prospective cohort study included 32 patients with transverse maxillary hypoplasia. Expansion was

  18. Bacterial food-borne pathogens in Indian food

    International Nuclear Information System (INIS)

    Bandekar, J.R.

    2015-01-01

    Food technology and food processing techniques have made tremendous advances in preservation of food and ensuring safety of food by killing food-borne pathogens. In addition to old techniques such as pasteurization, canning, dehydration, fermentation and salting, a number of new techniques such as radiation processing, high pressure technology and pulsed electric field technology are being applied for preservation of food and to ensure food safety. Total Quality Management (TQM) concepts have been developed to take care of food safety from farm to table. Hazard Analysis at Critical Control Points (HACCP) is being applied for mass scale production of food to make food free from pathogens. Despite these advances, food-borne diseases have become one of the most widespread public health problems in the world. About two thirds of all the outbreaks are traced to microbial contaminated food. According to World Health Organization (WHO) estimates, food-borne and waterborne diarrhoeal diseases kill an estimated 2 million people annually, including many children. Food safety is a major concern not only for developing countries but also for the developed countries. A number of factors such as emergence of new food-borne pathogens, development of drug resistance in pathogens, changing life style, globalization of the food supply etc. are responsible for the continuous persistence of food-borne diseases. The food-borne disease outbreaks due to E. coli O157:H7, Listeria monocytogenes, Salmonella and Campylobacter, are responsible for recall of many foods resulting in heavy losses to food industry. Due to consumer demand, a number of Ready-To-Eat (RTE) minimally processed foods are increasingly marketed; however, there is increased risk of foodborne diseases with these products. Food Technology Division of Bhabha Atomic Research Centre, Mumbai, has been working on food-borne bacterial pathogens particularly Salmonella, Campylobacter, Listeria monocytogenes, Vibrio and Aeromonasf

  19. Magic moment? Maternal marriage for children born out of wedlock.

    Science.gov (United States)

    Gibson-Davis, Christina

    2014-08-01

    To test the existence of the "magic moment" for parental marriage immediately post-birth and to inform policies that preferentially encourage biological over step parent marriage, this study estimates the incidence and stability of maternal marriage for children born out of wedlock. Data came from the National Survey of Family Growth on 5,255 children born non maritally. By age 15, 29 % of children born non maritally experienced a biological-father marriage, and 36 % experienced a stepfather marriage. Stepfather marriages occurred much later in a child's life-one-half occurred after the child turned age 7-and had one-third higher odds of dissolution. Children born to black mothers had qualitatively different maternal marriage experiences than children born to white or Hispanic mothers, with less biological-parent marriage and higher incidences of divorce. Findings support the existence of the magic moment and demonstrate that biological marriages were more enduring than stepfather marriages. Yet relatively few children born out of wedlock experienced stable, biological-parent marriages as envisioned by marriage promotion programs.

  20. Pap Tests and Foreign-Born Women

    Centers for Disease Control (CDC) Podcasts

    2007-11-26

    Foreign-born women living in the U.S. are less likely to have Pap tests to detect cervical cancer than women born in this country. The problem is worse for women from certain countries or regions. Find out why this is a disturbing trend, who these women are and why they are less likely to get a Pap test, and what CDC is doing about it.  Created: 11/26/2007 by National Breast and Cervical Cancer Early Detection Program.   Date Released: 12/7/2007.

  1. Term infants born at home in Peru are less likely to be hospitalised in the neonatal period than those born in hospital.

    Science.gov (United States)

    Lavin, Tina; Preen, David B

    2017-08-01

    More than 50% of women worldwide give birth at home, but little is known about home birth and subsequent neonatal hospitalisation. The objective of the study was to investigate home birth and neonatal hospitalisation of term neonates in Peru. The relationship between birth setting [home - with or without skilled birth attendant (SBA), health centre, hospital] and neonatal hospitalisation (n = 1656) and incubator care (n = 1651) was investigated using data from the 2002 Young Lives Study. Infants were sampled from 20 sentinel sites across Peru. At each sentinel site 100 households with children aged 6-18 months were randomly sampled (therefore the sample only captured children surviving to 6 months of age). Multivariate regression modelling was used with models adjusted for a range of demographic and clinical factors. After adjustment, the odds of hospitalisation were lower in neonates born at home (with SBA OR 0.20, 95% CI 0.0-0.8, p = 0.021; without SBA OR = 0.4, 95% CI 0.2-0.7, p = 0.002) than in those born in hospital. Socio-demographic factors such as ethnicity, rural living, education, socio-economic status and access to transport did not influence neonatal hospitalisation, time in hospital, incubator care or time under incubator care. Neonates born at home were less likely to be hospitalised after birth owing to neonatal morbidity than neonates born in hospital. It is unclear whether this finding reflects poorer accessibility to hospital care for neonates born at home, or if neonates born at home required hospitalisation less frequently than neonates born in hospital owing to lower neonatal morbidity or other factors such as lower rates of medical intervention for home births. Further research is needed to explore the underlying mechanisms of these findings.

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

    Science.gov (United States)

    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

  3. Cancer in children and young adults born after assisted reproductive technology

    DEFF Research Database (Denmark)

    Sundh, Karin Jerhamre; Henningsen, Anna-Karina A; Källen, Karin

    2014-01-01

    STUDY QUESTION: Do children and young adults born after assisted reproductive technology (ART) have an increased risk of cancer? SUMMARY ANSWER: Children born after ART showed no overall increase in the rate of cancer when compared with children born as a result of spontaneous conception. WHAT...... IS KNOWN ALREADY: Children born after ART have more adverse perinatal outcomes, i.e. preterm births, low birthweights and birth defects. Previous studies have shown divergent results regarding the risk of cancer among children born after ART. STUDY DESIGN, SIZE, DURATION: A retrospective Nordic population...... group of children born after spontaneous conception. This control group was almost 4-fold the size of the ART group (n = 358 419) and matched for parity, year of birth and country. Data on perinatal outcomes and cancer were obtained from the National Medical Birth Registries, the Cancer Registries...

  4. Heat engines for dilatonic Born-Infeld black holes

    Energy Technology Data Exchange (ETDEWEB)

    Bhamidipati, Chandrasekhar; Yerra, Pavan Kumar [Indian Institute of Technology Bhubaneswar, School of Basic Sciences, Bhubaneswar (India)

    2017-08-15

    In the context of dilaton coupled Einstein gravity with a negative cosmological constant and a Born-Infeld field, we study heat engines where a charged black hole is the working substance. Using the existence of a notion of thermodynamic mass and volume (which depend on the dilaton coupling), the mechanical work takes place via the pdV terms present in the first law of extended gravitational thermodynamics. The efficiency is analyzed as a function of dilaton and Born-Infeld couplings, and the results are compared with analogous computations in the related conformal solutions in the Brans-Dicke-Born-Infeld theory and black holes in anti-de Sitter space-time. (orig.)

  5. Large baby syndrome in singletons born after frozen embryo transfer (FET)

    DEFF Research Database (Denmark)

    Pinborg, Anja; Henningsen, AA; Loft, A

    2013-01-01

    Are singletons born after frozen embryo transfer (FET) at increased risk of being born large for gestational age (LGA) and if so, is this caused by intrinsic maternal factors or related to the freezing/thawing procedures?......Are singletons born after frozen embryo transfer (FET) at increased risk of being born large for gestational age (LGA) and if so, is this caused by intrinsic maternal factors or related to the freezing/thawing procedures?...

  6. Genius in the shadows a biography of Leo Szilard, the man behind the bomb

    CERN Document Server

    Lanouette, William

    2013-01-01

    Well-known names such as Albert Einstein, Enrico Fermi, J. Robert Oppenheimer, and Edward Teller are usually those that surround the creation of the atom bomb. One name that is rarely mentioned is Leo Szilard, known in scientific circles as "father of the atom bomb." The man who first developed the idea of harnessing energy from nuclear chain reactions, he is curiously buried with barely a trace in the history of this well-known and controversial topic.Born in Hungary and educated in Berlin, he escaped Hitler's Germany in 1933 and that first year developed his concept of nucle

  7. Human to human transmission of arthropod-borne pathogens

    NARCIS (Netherlands)

    Martina, B.E.; Barzon, L.; Pijlman, G.P.; Fuente, J. de la; Rizzoli, A.; Wammes, L.J.; Takken, W.; Rij, R.P. van; Papa, A.

    2017-01-01

    Human-to-human (H2H) transmitted arthropod-borne pathogens are a growing burden worldwide, with malaria and dengue being the most common mosquito-borne H2H transmitted diseases. The ability of vectors to get infected by humans during a blood meal to further propel an epidemic depends on complex

  8. Three-dimensional evaluation of soft tissue changes in the orofacial region after tooth-borne and bone-borne surgically assisted rapid maxillary expansion

    NARCIS (Netherlands)

    Nada, R.M.; Loon, B. van; Maal, T.J.J.; Berge, S.J.; Mostafa, Y.A.; Kuijpers-Jagtman, A.M.; Schols, J.G.J.H.

    2013-01-01

    OBJECTIVES: This study seeks to three-dimensionally assess soft tissue changes in the orofacial region following tooth-borne and bone-borne surgically assisted rapid maxillary expansion (SARME). MATERIALS AND METHODS: This prospective cohort study included 40 skeletally mature patients with

  9. Non-Adiabatic Molecular Dynamics Methods for Materials Discovery

    Energy Technology Data Exchange (ETDEWEB)

    Furche, Filipp [Univ. of California, Irvine, CA (United States); Parker, Shane M. [Univ. of California, Irvine, CA (United States); Muuronen, Mikko J. [Univ. of California, Irvine, CA (United States); Roy, Saswata [Univ. of California, Irvine, CA (United States)

    2017-04-04

    The flow of radiative energy in light-driven materials such as photosensitizer dyes or photocatalysts is governed by non-adiabatic transitions between electronic states and cannot be described within the Born-Oppenheimer approximation commonly used in electronic structure theory. The non-adiabatic molecular dynamics (NAMD) methods based on Tully surface hopping and time-dependent density functional theory developed in this project have greatly extended the range of molecular materials that can be tackled by NAMD simulations. New algorithms to compute molecular excited state and response properties efficiently were developed. Fundamental limitations of common non-linear response methods were discovered and characterized. Methods for accurate computations of vibronic spectra of materials such as black absorbers were developed and applied. It was shown that open-shell TDDFT methods capture bond breaking in NAMD simulations, a longstanding challenge for single-reference molecular dynamics simulations. The methods developed in this project were applied to study the photodissociation of acetaldehyde and revealed that non-adiabatic effects are experimentally observable in fragment kinetic energy distributions. Finally, the project enabled the first detailed NAMD simulations of photocatalytic water oxidation by titania nanoclusters, uncovering the mechanism of this fundamentally important reaction for fuel generation and storage.

  10. Nonadiabatic effects in electronic and nuclear dynamics

    Directory of Open Access Journals (Sweden)

    Martin P. Bircher

    2017-11-01

    Full Text Available Due to their very nature, ultrafast phenomena are often accompanied by the occurrence of nonadiabatic effects. From a theoretical perspective, the treatment of nonadiabatic processes makes it necessary to go beyond the (quasi static picture provided by the time-independent Schrödinger equation within the Born-Oppenheimer approximation and to find ways to tackle instead the full time-dependent electronic and nuclear quantum problem. In this review, we give an overview of different nonadiabatic processes that manifest themselves in electronic and nuclear dynamics ranging from the nonadiabatic phenomena taking place during tunnel ionization of atoms in strong laser fields to the radiationless relaxation through conical intersections and the nonadiabatic coupling of vibrational modes and discuss the computational approaches that have been developed to describe such phenomena. These methods range from the full solution of the combined nuclear-electronic quantum problem to a hierarchy of semiclassical approaches and even purely classical frameworks. The power of these simulation tools is illustrated by representative applications and the direct confrontation with experimental measurements performed in the National Centre of Competence for Molecular Ultrafast Science and Technology.

  11. Molecular Eigensolution Symmetry Analysis and Fine Structure

    Directory of Open Access Journals (Sweden)

    William G. Harter

    2013-01-01

    Full Text Available Spectra of high-symmetry molecules contain fine and superfine level cluster structure related to J-tunneling between hills and valleys on rovibronic energy surfaces (RES. Such graphic visualizations help disentangle multi-level dynamics, selection rules, and state mixing effects including widespread violation of nuclear spin symmetry species. A review of RES analysis compares it to that of potential energy surfaces (PES used in Born-Oppenheimer approximations. Both take advantage of adiabatic coupling in order to visualize Hamiltonian eigensolutions. RES of symmetric and D2 asymmetric top rank-2-tensor Hamiltonians are compared with Oh spherical top rank-4-tensor fine-structure clusters of 6-fold and 8-fold tunneling multiplets. Then extreme 12-fold and 24-fold multiplets are analyzed by RES plots of higher rank tensor Hamiltonians. Such extreme clustering is rare in fundamental bands but prevalent in hot bands, and analysis of its superfine structure requires more efficient labeling and a more powerful group theory. This is introduced using elementary examples involving two groups of order-6 (C6 and D3~C3v, then applied to families of Oh clusters in SF6 spectra and to extreme clusters.

  12. Dissociation energies of six NO2 isotopologues by laser induced fluorescence spectroscopy and zero point energy of some triatomic molecules.

    Science.gov (United States)

    Michalski, G; Jost, R; Sugny, D; Joyeux, M; Thiemens, M

    2004-10-15

    We have measured the rotationless photodissociation threshold of six isotopologues of NO2 containing 14N, 15N, 16O, and 18O isotopes using laser induced fluorescence detection and jet cooled NO2 (to avoid rotational congestion). For each isotopologue, the spectrum is very dense below the dissociation energy while fluorescence disappears abruptly above it. The six dissociation energies ranged from 25 128.56 cm(-1) for 14N16O2 to 25 171.80 cm(-1) for 15N18O2. The zero point energy for the NO2 isotopologues was determined from experimental vibrational energies, application of the Dunham expansion, and from canonical perturbation theory using several potential energy surfaces. Using the experimentally determined dissociation energies and the calculated zero point energies of the parent NO2 isotopologue and of the NO product(s) we determined that there is a common De = 26 051.17+/-0.70 cm(-1) using the Born-Oppenheimer approximation. The canonical perturbation theory was then used to calculate the zero point energy of all stable isotopologues of SO2, CO2, and O3, which are compared with previous determinations.

  13. Quantum Monte Carlo for atoms and molecules

    International Nuclear Information System (INIS)

    Barnett, R.N.

    1989-11-01

    The diffusion quantum Monte Carlo with fixed nodes (QMC) approach has been employed in studying energy-eigenstates for 1--4 electron systems. Previous work employing the diffusion QMC technique yielded energies of high quality for H 2 , LiH, Li 2 , and H 2 O. Here, the range of calculations with this new approach has been extended to include additional first-row atoms and molecules. In addition, improvements in the previously computed fixed-node energies of LiH, Li 2 , and H 2 O have been obtained using more accurate trial functions. All computations were performed within, but are not limited to, the Born-Oppenheimer approximation. In our computations, the effects of variation of Monte Carlo parameters on the QMC solution of the Schroedinger equation were studied extensively. These parameters include the time step, renormalization time and nodal structure. These studies have been very useful in determining which choices of such parameters will yield accurate QMC energies most efficiently. Generally, very accurate energies (90--100% of the correlation energy is obtained) have been computed with single-determinant trail functions multiplied by simple correlation functions. Improvements in accuracy should be readily obtained using more complex trial functions

  14. Trajectory-based nonadiabatic dynamics with time-dependent density functional theory.

    Science.gov (United States)

    Curchod, Basile F E; Rothlisberger, Ursula; Tavernelli, Ivano

    2013-05-10

    Understanding the fate of an electronically excited molecule constitutes an important task for theoretical chemistry, and practical implications range from the interpretation of atto- and femtosecond spectroscopy to the development of light-driven molecular machines, the control of photochemical reactions, and the possibility of capturing sunlight energy. However, many challenging conceptual and technical problems are involved in the description of these phenomena such as 1) the failure of the well-known Born-Oppenheimer approximation; 2) the need for accurate electronic properties such as potential energy surfaces, excited nuclear forces, or nonadiabatic coupling terms; and 3) the necessity of describing the dynamics of the photoexcited nuclear wavepacket. This review provides an overview of the current methods to address points 1) and 3) and shows how time-dependent density functional theory (TDDFT) and its linear-response extension can be used for point 2). First, the derivation of Ehrenfest dynamics and nonadiabatic Bohmian dynamics is discussed and linked to Tully's trajectory surface hopping. Second, the coupling of these trajectory-based nonadiabatic schemes with TDDFT is described in detail with special emphasis on the derivation of the required electronic structure properties. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Dielectric functions, pseudopotentials and applications to lattice dynamics

    International Nuclear Information System (INIS)

    Sinha, S.K.

    1975-01-01

    An attempt has been made to review the method of calculating the phonon spectra of crystals in terms of the basic electronic structure. Solids with defects, disordered solids and anharmonic effects have been excluded. The most general technique, viz. the Born-Oppenheimer perturbation theory has been discussed. The structure of the dynamic matrix has been discussed and the manifestations of the Fermi surface in the phonon spectrum explained. A pseudopotential concept for the free electron like metals has been justified and a brief account of these potentials from the point of view of the OPW method as well as from that of the phase shift analysis is included. The formalism of the basic results of the phenomenological dipolar models and their recent generalizations have been reviewed. It has pointed out that this could be derived from the microscopic theory by factorization approximation for the dielectric matrix, and the same method could lead even to more general models and the dielectric properties of the crystal could be obtained from such a microscopic theory. It is expected that the results may be applied to optical properties of the crystal. (K.B.)

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

    Science.gov (United States)

    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.

  17. Spectrophotometric determination of substrate-borne polyacrylamide.

    Science.gov (United States)

    Lu, Jianhang; Wu, Laosheng

    2002-08-28

    Polyacrylamides (PAMs) have wide application in many industries and in agriculture. Scientific research and industrial applications manifested a need for a method that can quantify substrate-borne PAM. The N-bromination method (a PAM analytical technique based on N-bromination of amide groups and spectrophotometric determination of the formed starch-triiodide complex), which was originally developed for determining PAM in aqueous solutions, was modified to quantify substrate-borne PAM. In the modified method, the quantity of substrate-borne PAM was converted to a concentration of starch-triiodide complex in aqueous solution that was then measured by spectrophotometry. The method sensitivity varied with substrates due to sorption of reagents and reaction intermediates on the substrates. Therefore, separate calibration for each substrate was required. Results from PAM samples in sand, cellulose, organic matter burnt soils, and clay minerals showed that this method had good accuracy and reproducibility. The PAM recoveries ranged from 95.8% to 103.7%, and the relative standard deviations (n = 4) were application and facilitating PAM-related research.

  18. Zoonotic aspects of vector-borne infections.

    Science.gov (United States)

    Failloux, A-B; Moutailler, S

    2015-04-01

    Vector-borne diseases are principally zoonotic diseases transmitted to humans by animals. Pathogens such as bacteria, parasites and viruses are primarily maintained within an enzootic cycle between populations of non-human primates or other mammals and largely non-anthropophilic vectors. This 'wild' cycle sometimes spills over in the form of occasional infections of humans and domestic animals. Lifestyle changes, incursions by humans into natural habitats and changes in agropastoral practices create opportunities that make the borders between wildlife and humans more permeable. Some vector-borne diseases have dispensed with the need for amplification in wild or domestic animals and they can now be directly transmitted to humans. This applies to some viruses (dengue and chikungunya) that have caused major epidemics. Bacteria of the genus Bartonella have reduced their transmission cycle to the minimum, with humans acting as reservoir, amplifier and disseminator. The design of control strategies for vector-borne diseases should be guided by research into emergence mechanisms in order to understand how a wild cycle can produce a pathogen that goes on to cause devastating urban epidemics.

  19. serological detection of seed borne viruses in cowpea regenerated

    African Journals Online (AJOL)

    Administrator

    out to detect the presence of seed borne viruses in fourteen cowpea accessions ... were serologically indexed to detect any seed-borne viruses after acclimatisation to screen house conditions. The .... showed external virus-like symptoms were.

  20. International Pricing Strategies for Born-Global Firms

    Directory of Open Access Journals (Sweden)

    Michael Neubert

    2017-10-01

    Full Text Available This paper aims to understand how born global firms develop their international pricing strategies, practices, and models. It aims to expand the study of international entrepreneurship and born global firms by including a broader and deeper range of pricing aspects than is normally found in the international entrepreneurship and pricing literature. The paper opted for a multiple case-study research design using different sources of evidence, including four in-depth interviews with CEOs of born global firms. The case-study firms were selected using a purposive selection method. The theoretical framework of Ingenbleek, Frambach & Verhallen is used. The results suggest that successful leaders act as ‘integrating forces’ on two levels: by applying a structured and disciplined price-setting process with regular reviews and by mediating between corporate financial goals and the local market reality. The results support the claim that policy makers should offer insights, training and financial support to give promising born global firms the possibility to select the most efficient international pricing models and strategies. The results are relevant for entrepreneurs to understand the importance of efficient price-modelling processes and the influence of the different price strategies and price models on financial results and sales revenues.

  1. Human to human transmission of arthropod-borne pathogens

    NARCIS (Netherlands)

    Martina, Byron E.; Barzon, Luisa; Pijlman, Gorben P.; Fuente, de la José; Rizzoli, Annapaola; Wammes, Linda J.; Takken, Willem; Rij, van Ronald P.; Papa, Anna

    2017-01-01

    Human-to-human (H2H) transmitted arthropod-borne pathogens are a growing burden worldwide, with malaria and dengue being the most common mosquito-borne H2H transmitted diseases. The ability of vectors to get infected by humans during a blood meal to further propel an epidemic depends on complex

  2. Birth origin differentially affects depressive-like behaviours: are captive-born cynomolgus monkeys more vulnerable to depression than their wild-born counterparts?

    Directory of Open Access Journals (Sweden)

    Sandrine M J Camus

    Full Text Available BACKGROUND: Adverse early-life experience might lead to the expression of abnormal behaviours in animals and the predisposition to psychiatric disorder (e.g. major depressive disorder in Humans. Common breeding processes employ weaning and housing conditions different from what happens in the wild. METHODS: The present study, therefore, investigated whether birth origin impacts the possible existence of spontaneous atypical/abnormal behaviours displayed by 40 captive-born and 40 wild-born socially-housed cynomolgus macaques in farming conditions using an unbiased ethological scan-sampling analysis followed by multifactorial correspondence and hierarchical clustering analyses. RESULTS: We identified 10 distinct profiles (groups A to J that significantly differed on several behaviours, body postures, body orientations, distances between individuals and locations in the cage. Data suggest that 4 captive-born and 1 wild-born animals (groups G and J present depressive-like symptoms, unnatural early life events thereby increasing the risk of developing pathological symptoms. General differences were also highlighted between the captive- and wild-born populations, implying the expression of differential coping mechanisms in response to the same captive environment. CONCLUSIONS: Birth origin thus impacts the development of atypical ethologically-defined behavioural profiles, reminiscent of certain depressive-like symptoms. The use of unbiased behavioural observations might allow the identification of animal models of human mental/behavioural disorders and their most appropriate control groups.

  3. First- and second-born adolescents' decision-making autonomy throughout adolescence.

    Science.gov (United States)

    Campione-Barr, Nicole; Lindell, Anna K; Short, Stephen D; Greer, Kelly Bassett; Drotar, Scott D

    2015-12-01

    First- and second-born adolescents' and their parents' perceptions of adolescents' decision-making autonomy were compared from ages 12 to 19 in a longitudinal sample of 145 predominantly White, middle class families. Utilizing a multivariate, multilevel modeling approach, differences in perceptions of adolescents' autonomy between parents and each adolescent, as well as by social-cognitive domain were examined. The present study found that when comparing parents' perceptions of their children at the same age, second-borns were granted more autonomy regarding conventional issues than first-borns during early adolescence, but by later adolescence first-borns were granted more autonomy regarding prudential issues than second-borns. However, comparisons between adolescents' and siblings' perceptions showed no differences. Potential reasons for, and implications of, differences in perceptions of adolescent autonomy are discussed. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  4. Emerging vector borne diseases – incidence through vectors

    Directory of Open Access Journals (Sweden)

    Sara eSavic

    2014-12-01

    Full Text Available Vector borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowdays, in intercontinetal countries, there is a struggle with emerging diseases which have found their way to appear through vectors. Vector borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector borne infectious diseases and disease outbreaks. It could affect the range and popultion of pathogens, host and vectors, transmission season, etc. Reliable surveilance for diseases that are most likely to emerge is required. Canine vector borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, erlichiosis, leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fudamental role at primeraly prevention and then treatment of vector borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases.During a four year period, from 2009-2013, a total number of 551 dog samples were analysed for vector borne diseases (borreliosis, babesiosis, erlichiosis, anaplasmosis, dirofilariosis and leishmaniasis in routine laboratory work. The analysis were done by serological tests – ELISA for borreliosis, dirofilariosis and leishmaniasis, modified Knott test for dirofilariosis and blood smear for babesiosis, erlichiosis and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on avarege more then half of the samples

  5. High cancer mortality for US-born Latinos: evidence from California and Texas.

    Science.gov (United States)

    Pinheiro, Paulo S; Callahan, Karen E; Gomez, Scarlett Lin; Marcos-Gragera, Rafael; Cobb, Taylor R; Roca-Barcelo, Aina; Ramirez, Amelie G

    2017-07-11

    Latinos born in the US, 36 million, comprise 65% of all US Latinos. Yet their cancer experience is nearly always analyzed together with their foreign-born counterparts, 19 million, who constitute a steady influx of truly lower-risk populations from abroad. To highlight specific cancer vulnerabilities for US-born Latinos, we compare their cancer mortality to the majority non-Latino white (NLW) population, foreign-born Latinos, and non-Latino blacks. We analyzed 465,751 cancer deaths from 2008 to 2012 occurring among residents of California and Texas, the two most populous states, accounting for 47% of US Latinos. This cross-sectional analysis, based on granular data obtained from death certificates on cause of death, age, race, ethnicity and birthplace, makes use of normal standardization techniques and negative binomial regression models. While Latinos overall have lower all-cancers-combined mortality rates than NLWs, these numbers were largely driven by low rates among the foreign born while mortality rates for US-born Latinos approach those of NLWs. Among Texas males, rates were 210 per 100,000 for NLWs and 166 for Latinos combined, but 201 per 100,000 for US-born Latinos and 125 for foreign-born Latinos. Compared to NLWs, US-born Latino males in California had mortality rate ratios of 2.83 (95% CI: 2.52-3.18) for liver cancer, 1.44 (95% CI: 1.30-1.61) for kidney cancer, and 1.25 (95% CI: 1.17-1.34) for colorectal cancer (CRC). Texas results showed a similar site-specific pattern. Specific cancer patterns for US-born Latinos, who have relatively high cancer mortality, similar overall to NLWs, are masked by aggregation of all Latinos, US-born and foreign-born. While NLWs had high mortality for lung cancer, US-born Latinos had high mortality for liver, kidney and male colorectal cancers. HCV testing and reinforcement of the need for CRC screening should be a priority in this specific and understudied population. The unprecedented proximity of overall rates between

  6. Topologically nontrivial black holes in Lovelock-Born-Infeld gravity

    Science.gov (United States)

    Farhangkhah, N.

    2018-04-01

    We present the black hole solutions possessing horizon with nonconstant-curvature and additional scalar restrictions on the base manifold in Lovelock gravity coupled to Born-Infeld (BI) nonlinear electrodynamics. The asymptotic and near origin behavior of the metric is presented and we analyze different behaviors of the singularity. We find that, in contrast to the case of black hole solutions of BI-Lovelock gravity with constant curvature horizon and Maxwell-Lovelock gravity with non constant horizon which have only timelike singularities, spacelike, and timelike singularities may exist for BI-Lovelock black holes with nonconstant curvature horizon. By calculating the thermodynamic quantities, we study the effects of nonlinear electrodynamics via the Born-Infeld action. Stability analysis shows that black holes with positive sectional curvature, κ , possess an intermediate unstable phase and large and small black holes are stable. We see that while Ricci flat Lovelock-Born-Infeld black holes having exotic horizons are stable in the presence of Maxwell field or either Born Infeld field with large born Infeld parameter β , unstable phase appears for smaller values of β , and therefore nonlinearity brings in the instability.

  7. Black hole solutions in mimetic Born-Infeld gravity.

    Science.gov (United States)

    Chen, Che-Yu; Bouhmadi-López, Mariam; Chen, Pisin

    2018-01-01

    The vacuum, static, and spherically symmetric solutions in the mimetic Born-Infeld gravity are studied. The mimetic Born-Infeld gravity is a reformulation of the Eddington-inspired-Born-Infeld (EiBI) model under the mimetic approach. Due to the mimetic field, the theory contains non-trivial vacuum solutions different from those in Einstein gravity. We find that with the existence of the mimetic field, the spacelike singularity inside a Schwarzschild black hole could be altered to a lightlike singularity, even though the curvature invariants still diverge at the singularity. Furthermore, in this case, the maximal proper time for a timelike radially-infalling observer to reach the singularity is found to be infinite.

  8. Black hole solutions in mimetic Born-Infeld gravity

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Che-Yu [National Taiwan University, Department of Physics and Center for Theoretical Sciences, Taipei (China); LeCosPA, National Taiwan University, Taipei (China); Bouhmadi-Lopez, Mariam [University of the Basque Country UPV/EHU, Department of Theoretical Physics, Bilbao (Spain); IKERBASQUE, Basque Foundation for Science, Bilbao (Spain); Chen, Pisin [National Taiwan University, Department of Physics and Center for Theoretical Sciences, Taipei (China); LeCosPA, National Taiwan University, Taipei (China); Stanford University, Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Stanford, CA (United States)

    2018-01-15

    The vacuum, static, and spherically symmetric solutions in the mimetic Born-Infeld gravity are studied. The mimetic Born-Infeld gravity is a reformulation of the Eddington-inspired-Born-Infeld (EiBI) model under the mimetic approach. Due to the mimetic field, the theory contains non-trivial vacuum solutions different from those in Einstein gravity. We find that with the existence of the mimetic field, the spacelike singularity inside a Schwarzschild black hole could be altered to a lightlike singularity, even though the curvature invariants still diverge at the singularity. Furthermore, in this case, the maximal proper time for a timelike radially-infalling observer to reach the singularity is found to be infinite. (orig.)

  9. First-born siblings show better second language skills than later born siblings

    Science.gov (United States)

    Keller, Karin; Troesch, Larissa M.; Grob, Alexander

    2015-01-01

    We examined the extent to which three sibling structure variables number of siblings, birth order, and presence of an older sibling at school age are linked to the second language skills of bilingual children. The research questions were tested using an ethnically heterogeneous sample of 1209 bilingual children with German as a second language. Controlling for children’s age, sex, nationality, number of children’s books at home, family language and parental German language skills, hierarchical regression analyses showed an inverse relationship between the number of siblings and second language skills: the more siblings a child had, the lower was his/her second language proficiency. This relationship was mediated by attendance in early education institutions. Moreover, first-born siblings showed better second language skills than later born siblings. The current study revealed that the resource dilution model, i.e., the decrease in resources for every additional sibling, holds for second language acquisition. Moreover, the results indicate that bilingual children from families with several children benefit from access to early education institutions. PMID:26089806

  10. First-born siblings show better second language skills than later born siblings

    Directory of Open Access Journals (Sweden)

    Karin eKeller

    2015-06-01

    Full Text Available We examined the extent to which three sibling structure variables number of siblings, birth order and presence of an older sibling at school age are linked to the second language skills of bilingual children. The research questions were tested using an ethnically heterogeneous sample of 1209 bilingual children with German as a second language. Controlling for children’s age, sex, nationality, number of children’s books at home, family language and parental German language skills, hierarchical regression analyses showed an inverse relationship between the number of siblings and second language skills: The more siblings a child had, the lower was his/her second language proficiency. This relationship was mediated by attendance in early education institutions. Moreover, first-born siblings showed better second language skills than later born siblings.The current study revealed that the resource dilution model, i.e., the decrease in resources for every additional sibling, holds for second language acquisition. Moreover, the results indicate that bilingual children from families with several children benefit from access to early education institutions.

  11. Practical solutions to implementing "Born Semantic" data systems

    Science.gov (United States)

    Leadbetter, A.; Buck, J. J. H.; Stacey, P.

    2015-12-01

    The concept of data being "Born Semantic" has been proposed in recent years as a Semantic Web analogue to the idea of data being "born digital"[1], [2]. Within the "Born Semantic" concept, data are captured digitally and at a point close to the time of creation are annotated with markup terms from semantic web resources (controlled vocabularies, thesauri or ontologies). This allows heterogeneous data to be more easily ingested and amalgamated in near real-time due to the standards compliant annotation of the data. In taking the "Born Semantic" proposal from concept to operation, a number of difficulties have been encountered. For example, although there are recognised methods such as Header, Dictionary, Triples [3] for the compression, publication and dissemination of large volumes of triples these systems are not practical to deploy in the field on low-powered (both electrically and computationally) devices. Similarly, it is not practical for instruments to output fully formed semantically annotated data files if they are designed to be plugged into a modular system and the data to be centrally logged in the field as is the case on Argo floats and oceanographic gliders where internal bandwidth becomes an issue [2]. In light of these issues, this presentation will concentrate on pragmatic solutions being developed to the problem of generating Linked Data in near real-time systems. Specific examples from the European Commission SenseOCEAN project where Linked Data systems are being developed for autonomous underwater platforms, and from work being undertaken in the streaming of data from the Irish Galway Bay Cable Observatory initiative will be highlighted. Further, developments of a set of tools for the LogStash-ElasticSearch software ecosystem to allow the storing and retrieval of Linked Data will be introduced. References[1] A. Leadbetter & J. Fredericks, We have "born digital" - now what about "born semantic"?, European Geophysical Union General Assembly, 2014

  12. Shattered Shangri-la: differences in depressive and anxiety symptoms in students born in Tibet compared to Tibetan students born in exile.

    Science.gov (United States)

    Evans, Dabney; Buxton, David C; Borisov, Andrey; Manatunga, Amita K; Ngodup, Dawa; Raison, Charles L

    2008-06-01

    As a result of ongoing political tensions within Tibetan regions of the People's Republic of China, several thousand Tibetans escape across the Himalayas every year to seek refuge in India and Nepal. Prior studies have found a high prevalence of depressive and anxiety symptoms in these refugees, many of whom are young and have been exposed to significant trauma. However, it is not known whether depressive and anxiety symptoms are more prevalent in these refugees than in ethnic Tibetans born and raised in the relative political and social stability of exile communities in North India and Nepal. We conducted a cross-sectional survey of a convenience sample of 319 students attending school at the Tibetan Children's Villages in Northern India to test the a priori hypothesis that adolescents and young adults who escaped from Tibet to India would demonstrate increased depressive and anxiety symptoms when compared to ethnic Tibetans born and raised in exile. The Hopkins Symptom Checklist-25 (HSCL-25) was used to measure depressive and anxiety symptoms. In addition, demographic information on age, sex, country of birth and frequency of family contact was collected. Students born in Tibet had higher mean HSCL-25 depressive and anxiety symptom scores than did ethnic Tibetans born in exile. Female students demonstrated higher depressive and anxiety scores, as did those with limited contact with immediate family. After adjusting for sex, age and frequency of family contact, being born in Tibet was associated with increased HSCL-25 depressive and anxiety symptom scores (depression: F[2, 316] = 29.96, P < 0.0001; anxiety: F[4, 316] = 43.57, P < 0.0001). The experience of being raised in Tibet and escaping to India appears to be a risk factor for increased depressive and anxiety symptoms when compared to being born and raised within an exile community in India or Nepal.

  13. Vector borne diseases

    OpenAIRE

    Melillo Fenech, Tanya

    2010-01-01

    A vector-borne disease is one in which the pathogenic microorganism is transmitted from an infected individual to another individual by an arthropod or other agent. The transmission depends upon the attributes and requirements of at least three different Iiving organisms : the pathologic agent which is either a virus, protozoa, bacteria or helminth (worm); the vector, which is commonly an arthropod such as ticks or mosquitoes; and the human host.

  14. Social development of children born very preterm: a systematic review.

    Science.gov (United States)

    Ritchie, Kirsten; Bora, Samudragupta; Woodward, Lianne J

    2015-10-01

    To review systematically studies examining the development of social competence in children born very preterm (VPT) (gestation skills. Twenty-three studies were included. Seven focused on social competence and another 16 examined social competence within a range of outcomes. Study quality was low. Limitations included reliance on single informant data, cross-sectional measurement, use of brief screening tools, absence of child or peer report, and no conceptual model. In terms of social adjustment, 16 out of 21 studies found children born VPT had more peer problems and social withdrawal. Findings of social performance were mixed, with some studies suggesting differences in prosocial behavior (4/14) and others not. Social skills were assessed in four studies and showed children born VPT had poorer skills than children born at term. Predictors of social competence included gestational age, neonatal brain abnormalities, and family socio-economic status. Children born VPT have poorer social competence. These difficulties emerge early and persist throughout childhood. © 2015 Mac Keith Press.

  15. Horizon structure of rotating Einstein-Born-Infeld black holes and shadow

    Energy Technology Data Exchange (ETDEWEB)

    Atamurotov, Farruh [Institute of Nuclear Physics, Tashkent (Uzbekistan); Inha University in Tashkent, Tashkent (Uzbekistan); Ulugh Beg Astronomical Institute, Tashkent (Uzbekistan); National University of Uzbekistan, Tashkent (Uzbekistan); Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); University of Kwa-Zulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, Private Bag 54001, Durban (South Africa); Ahmedov, Bobomurat [Institute of Nuclear Physics, Tashkent (Uzbekistan); Ulugh Beg Astronomical Institute, Tashkent (Uzbekistan); National University of Uzbekistan, Tashkent (Uzbekistan)

    2016-05-15

    We investigate the horizon structure of the rotating Einstein-Born-Infeld solution which goes over to the Einstein-Maxwell's Kerr-Newman solution as the Born-Infeld parameter goes to infinity (β → ∞). We find that for a given β, mass M, and charge Q, there exist a critical spinning parameter a{sub E} and r{sub H}{sup E}, which corresponds to an extremal Einstein-Born-Infeld black hole with degenerate horizons, and a{sub E} decreases and r{sub H}{sup E} increases with increase of the Born-Infeld parameter β, while a < a{sub E} describes a non-extremal Einstein-Born-Infeld black hole with outer and inner horizons. Similarly, the effect of β on the infinite redshift surface and in turn on the ergo-region is also included. It is well known that a black hole can cast a shadow as an optical appearance due to its strong gravitational field. We also investigate the shadow cast by the both static and rotating Einstein-Born-Infeld black hole and demonstrate that the null geodesic equations can be integrated, which allows us to investigate the shadow cast by a black hole which is found to be a dark zone covered by a circle. Interestingly, the shadow of an Einstein-Born-Infeld black hole is slightly smaller than for the Reissner-Nordstrom black hole, which consists of concentric circles, for different values of the Born-Infeld parameter β, whose radius decreases with increase of the value of the parameter β. Finally, we have studied observable distortion parameter for shadow of the rotating Einstein-Born-Infeld black hole. (orig.)

  16. Horizon structure of rotating Einstein-Born-Infeld black holes and shadow

    International Nuclear Information System (INIS)

    Atamurotov, Farruh; Ghosh, Sushant G.; Ahmedov, Bobomurat

    2016-01-01

    We investigate the horizon structure of the rotating Einstein-Born-Infeld solution which goes over to the Einstein-Maxwell's Kerr-Newman solution as the Born-Infeld parameter goes to infinity (β → ∞). We find that for a given β, mass M, and charge Q, there exist a critical spinning parameter a E and r H E , which corresponds to an extremal Einstein-Born-Infeld black hole with degenerate horizons, and a E decreases and r H E increases with increase of the Born-Infeld parameter β, while a < a E describes a non-extremal Einstein-Born-Infeld black hole with outer and inner horizons. Similarly, the effect of β on the infinite redshift surface and in turn on the ergo-region is also included. It is well known that a black hole can cast a shadow as an optical appearance due to its strong gravitational field. We also investigate the shadow cast by the both static and rotating Einstein-Born-Infeld black hole and demonstrate that the null geodesic equations can be integrated, which allows us to investigate the shadow cast by a black hole which is found to be a dark zone covered by a circle. Interestingly, the shadow of an Einstein-Born-Infeld black hole is slightly smaller than for the Reissner-Nordstrom black hole, which consists of concentric circles, for different values of the Born-Infeld parameter β, whose radius decreases with increase of the value of the parameter β. Finally, we have studied observable distortion parameter for shadow of the rotating Einstein-Born-Infeld black hole. (orig.)

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

    Science.gov (United States)

    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.

  18. Self-similar factor approximants

    International Nuclear Information System (INIS)

    Gluzman, S.; Yukalov, V.I.; Sornette, D.

    2003-01-01

    The problem of reconstructing functions from their asymptotic expansions in powers of a small variable is addressed by deriving an improved type of approximants. The derivation is based on the self-similar approximation theory, which presents the passage from one approximant to another as the motion realized by a dynamical system with the property of group self-similarity. The derived approximants, because of their form, are called self-similar factor approximants. These complement the obtained earlier self-similar exponential approximants and self-similar root approximants. The specific feature of self-similar factor approximants is that their control functions, providing convergence of the computational algorithm, are completely defined from the accuracy-through-order conditions. These approximants contain the Pade approximants as a particular case, and in some limit they can be reduced to the self-similar exponential approximants previously introduced by two of us. It is proved that the self-similar factor approximants are able to reproduce exactly a wide class of functions, which include a variety of nonalgebraic functions. For other functions, not pertaining to this exactly reproducible class, the factor approximants provide very accurate approximations, whose accuracy surpasses significantly that of the most accurate Pade approximants. This is illustrated by a number of examples showing the generality and accuracy of the factor approximants even when conventional techniques meet serious difficulties

  19. Profile of tuberculosis among the foreign-born population in Japan, 2007-2014.

    Science.gov (United States)

    Kawatsu, Lisa; Uchimura, Kazuhiro; Izumi, Kiyohiko; Ohkado, Akihiro; Ishikawa, Nobukatsu

    2016-01-01

    The proportion of foreign-born people among the newly notified tuberculosis (TB) patients has been increasing in recent years and potentially poses a new challenge to TB control in Japan. In this report, we analysed the data from the Japan TB surveillance system between 2007 and 2014 to gain an overview of the trends and characteristics of foreign-born TB patients in Japan. We found that the proportion of foreign-born TB patients was especially high among the younger age groups - 44.1% among the 20-29 years age group in 2014. The largest groups of foreign-born patients were from China and the Philippines; however, the number of those from Nepal and Viet Nam was on the rise. Students comprised the second largest professional category group for TB after regular workers, and its proportion increased over the study period. Compared to Japan-born TB patients, foreign-born patients were more likely to be diagnosed through routine medical check-ups. Treatment successes and patients still on treatment were significantly lower among foreign-born patients than their Japan-born counterparts; and transferred-out and unknown outcomes were higher. Our results indicated that distinctive subgroups within the foreign-born population in Japan, especially students and regular workers, might have a higher risk of developing TB. Measures to ensure early diagnosis and treatment adherence should be adapted to such populations.

  20. Mandibular function, temporomandibular disorders, and headache in prematurely born children.

    Science.gov (United States)

    Paulsson, Liselotte; Ekberg, Ewacarin; Nilner, Maria; Bondemark, Lars

    2009-01-01

    To evaluate mandibular function, signs, and symptoms of temporomandibular disorders (TMDs) and headache in prematurely born 8- to 10-year-old children, and to compare the findings with matched full-term born controls. Seventy-three preterm children were selected from the Medical Birth Register--one group comprising 36 extremely preterm children born before the 29th gestational week, the other group 37 very preterm children born during gestational weeks 29 to 32. The preterm children were compared with a control group of 41 full-term children matched for gender, age, nationality, and living area. The subjective symptoms of TMD and headache were registered using a questionnaire. Mandibular function, signs, and symptoms of TMD and headache were registered. TMD diagnoses were set per Research Diagnostic Criteria for temporomandibular disorders (RDC/TMD). No significant differences between groups or gender were found for TMD diagnoses according to RDC/TMD or for headache. The preterm children had smaller mandibular movement capacity than the full-term control group, but when adjusting for weight, height, and head circumference mostly all group differences disappeared. Prematurely born children of 8 to 10 years of age did not differ from full-term born children when considering diagnoses according to RDC/TMD, signs, and symptoms of TMD or headache.

  1. Travel patterns and characteristics of foreign-born sub-population in New York state

    Energy Technology Data Exchange (ETDEWEB)

    Chin, Shih-Miao [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hwang, Ho-Ling [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Reuscher, Tim [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wilson, Daniel W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-10-01

    According to the 2010 Census, over 22% of total New York State (NYS) residents were foreign-born and over one in three persons living in New York City (NYC) were foreign-born. Foreign-born and their dependents impact local economies in many different ways, including purchasing power, transportation service needs, business sales and receipts generated, and workforce. To allow better policy decision making and program planning of transportation developments and investments in NYS, a clear understanding of the foreign-born population’s travel characteristics and behaviors, as well as their unique transportation service needs, are necessary. This report documents the characteristics of the foreign-born population and identified differences in travel behaviors and mobility issues between foreign-born residents of NYS and their U.S.-born counterparts.

  2. Modulated Pade approximant

    International Nuclear Information System (INIS)

    Ginsburg, C.A.

    1980-01-01

    In many problems, a desired property A of a function f(x) is determined by the behaviour of f(x) approximately equal to g(x,A) as x→xsup(*). In this letter, a method for resuming the power series in x of f(x) and approximating A (modulated Pade approximant) is presented. This new approximant is an extension of a resumation method for f(x) in terms of rational functions. (author)

  3. Approximate Dynamic Programming: Combining Regional and Local State Following Approximations.

    Science.gov (United States)

    Deptula, Patryk; Rosenfeld, Joel A; Kamalapurkar, Rushikesh; Dixon, Warren E

    2018-06-01

    An infinite-horizon optimal regulation problem for a control-affine deterministic system is solved online using a local state following (StaF) kernel and a regional model-based reinforcement learning (R-MBRL) method to approximate the value function. Unlike traditional methods such as R-MBRL that aim to approximate the value function over a large compact set, the StaF kernel approach aims to approximate the value function in a local neighborhood of the state that travels within a compact set. In this paper, the value function is approximated using a state-dependent convex combination of the StaF-based and the R-MBRL-based approximations. As the state enters a neighborhood containing the origin, the value function transitions from being approximated by the StaF approach to the R-MBRL approach. Semiglobal uniformly ultimately bounded (SGUUB) convergence of the system states to the origin is established using a Lyapunov-based analysis. Simulation results are provided for two, three, six, and ten-state dynamical systems to demonstrate the scalability and performance of the developed method.

  4. Mathematical analysis of the boundary-integral based electrostatics estimation approximation for molecular solvation: exact results for spherical inclusions.

    Science.gov (United States)

    Bardhan, Jaydeep P; Knepley, Matthew G

    2011-09-28

    We analyze the mathematically rigorous BIBEE (boundary-integral based electrostatics estimation) approximation of the mixed-dielectric continuum model of molecular electrostatics, using the analytically solvable case of a spherical solute containing an arbitrary charge distribution. Our analysis, which builds on Kirkwood's solution using spherical harmonics, clarifies important aspects of the approximation and its relationship to generalized Born models. First, our results suggest a new perspective for analyzing fast electrostatic models: the separation of variables between material properties (the dielectric constants) and geometry (the solute dielectric boundary and charge distribution). Second, we find that the eigenfunctions of the reaction-potential operator are exactly preserved in the BIBEE model for the sphere, which supports the use of this approximation for analyzing charge-charge interactions in molecular binding. Third, a comparison of BIBEE to the recent GBε theory suggests a modified BIBEE model capable of predicting electrostatic solvation free energies to within 4% of a full numerical Poisson calculation. This modified model leads to a projection-framework understanding of BIBEE and suggests opportunities for future improvements. © 2011 American Institute of Physics

  5. Development of preschool and academic skills in children born very preterm

    NARCIS (Netherlands)

    Aarnoudse-Moens, C.S.H.; Oosterlaan, J.; Duivenvoorden, H.J.; van Goudoever, J.B.; Weisglas-Kuperus, N.

    2011-01-01

    Objective: To examine performance in preschool and academic skills in very preterm (gestational age ≤30 weeks) and term-born comparison children aged 4 to 12 years. Study design: Very preterm children (n = 200; mean age, 8.2 ± 2.5 years) born between 1996 and 2004 were compared with 230 term-born

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

    Science.gov (United States)

    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.

  7. Growth and development in children born very low birthweight.

    Science.gov (United States)

    Scharf, Rebecca J; Stroustrup, Annemarie; Conaway, Mark R; DeBoer, Mark D

    2016-09-01

    To examine the relationships between growth (birth to age 2 years) and developmental outcomes in children born with very low birthweight (VLBW). Motor and mental development in children born with VLBW were regressed on anthropometric measurements at birth, 9 months and 2 years using multivariable regression. The Early Childhood Longitudinal Study-Birth Cohort, a longitudinal cohort, community sample, designed to be representative of children born across the USA. 950 children born with VLBW (children exhibited poor growth, with length-for-age z-scores children at 9 months (adjusted for prematurity) and 34.2% of children at 2 years. Compared with children having z-scores >-2, children with growth shortfalls in head circumference, length and weight had a higher adjusted OR (aOR) of low Bayley motor scores at 9 months and 2 years (aOR ranging from 1.8 to 3.3, all pchildren born with VLBW. While careful length measures may be a particularly useful marker, deficits in all anthropometric measures were risk factors for developmental delays. 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/

  8. Emerging arthropod-borne diseases of companion animals in Europe.

    Science.gov (United States)

    Beugnet, Frederic; Marié, Jean-Lou

    2009-08-26

    Vector-borne diseases are caused by parasites, bacteria or viruses transmitted by the bite of hematophagous arthropods (mainly ticks and mosquitoes). The past few years have seen the emergence of new diseases, or re-emergence of existing ones, usually with changes in their epidemiology (i.e. geographical distribution, prevalence, and pathogenicity). The frequency of some vector-borne diseases of pets is increasing in Europe, i.e. canine babesiosis, granulocytic anaplasmosis, canine monocytic ehrlichiosis, thrombocytic anaplasmosis, and leishmaniosis. Except for the last, these diseases are transmitted by ticks. Both the distribution and abundance of the three main tick species, Rhipicephalus sanguineus, Dermacentor reticulatus and Ixodes ricinus are changing. The conditions for such changes involve primarily human factors, such as travel with pets, changes in human habitats, social and leisure activities, but climate changes also have a direct impact on arthropod vectors (abundance, geographical distribution, and vectorial capacity). Besides the most known diseases, attention should be kept on tick-borne encephalitis, which seems to be increasing in western Europe, as well as flea-borne diseases like the flea-transmitted rickettsiosis. Here, after consideration of the main reasons for changes in tick vector ecology, an overview of each "emerging" vector-borne diseases of pets is presented.

  9. Observational constraints on electromagnetic Born-Infeld cosmology

    International Nuclear Information System (INIS)

    Bretón, Nora; Montiel, Ariadna; Lazkoz, Ruth

    2012-01-01

    The cosmological model consisting of an electromagnetic Born-Infeld (BI) field coupled to a Robertson-Walker geometry is tested with the standard probes of SNIa, GRBs and direct Hubble parameter. The analysis shows that the inclusion of the nonlinear electromagnetic component does not contribute in a significative way to the observed expansion. The BI electromagnetic matter is considered with an abundance of Ω BI , that our best fit leads to Ω BI = 0.037 when tested with SNIa and the Hubble parameter data (0.1 BI = 0.304, which may indicate that this electrodynamics was important at epochs close to the appearance of large structure (z ≈ 7), although this late result has not as much reliability as that corresponding to the first two probes, since we know that the dispersion in GRBs data is still considerable. In view of these results we can rule out the electromagnetic Born-Infeld matter as the origin of the present accelerated expansion, this conclusion concerns exclusively the Born-Infeld theory

  10. Scattering Light by а Cylindrical Capsule with Arbitrary End Caps in the Rayleigh-Gans-Debye Approximation

    Directory of Open Access Journals (Sweden)

    K. A. Shapovalov

    2015-01-01

    Full Text Available The paper concerns the light scattering problem of biological objects of complicated structure.It considers optically “soft” (having a refractive index close to that of a surrounding medium homogeneous cylindrical capsules, composed of three parts: central one that is cylindrical and two symmetrical rounding end caps. Such capsules can model more broad class of biological objects than the ordinary shapes of a spheroid or sphere. But, unfortunately, if a particle has other than a regular geometrical shape, then it is very difficult or impossible to solve the scattering problem analytically in its most general form that oblige us to use numerical and approximate analytical methods. The one of such approximate analytical method is the Rayleigh-Gans-Debye approximation (or the first Born approximation.So, the Rayleigh-Gans-Debye approximation is valid for different objects having size from nanometer to millimeter and depending on wave length and refractive index of an object under small phase shift of central ray.The formulas for light scattering amplitude of cylindrical capsule with arbitrary end caps in the Rayleigh-Gans-Debye approximation in scalar form are obtained. Then the light scattering phase function [or element of scattering matrix f11] for natural incident light (unpolarized or arbitrary polarized light is calculated.Numerical results for light scattering phase functions of cylindrical capsule with conical, spheroidal, paraboloidal ends in the Rayleigh-Gans-Debye approximation are compared. Also numerical results for light scattering phase function of cylindrical capsule with conical ends in the Rayleigh-Gans-Debye approximation and in the method of Purcell-Pennypacker (or Discrete Dipole method are compared. The good agreement within an application range of the RayleighGans-Debye approximation is obtained.Further continuation of the work, perhaps, is a consideration of multilayer cylindrical capsule in the Rayleigh

  11. Comparison outcomes of sick babies born to teenage mothers with those born to adult mothers.

    Science.gov (United States)

    Chotigeat, Uraiwan; Sawasdiworn, Siraporn

    2011-08-01

    Adolescent period is the transitional stage of physical and mental development from childhood to adulthood. Pregnancy in teenage girls is generally classified to have a higher risk than those in adults. In many previous studies reported only the outcome of teenage mothers but no comparative outcome between sick babies born to teen mothers and adult mothers, so the authors conducted the present study. To compare the outcomes of sick infants born to teenage mothers with those born to adult mothers (age > or = 20 years). This prospective study was carried out from October 1st, 2006 to September 30th, 2009. The study group consisted of sick babies born to teenage mothers and admitted at Queen Sirikit National Institute of Child Health (QSNICH). These babies were compared to sick babies (control group) born to adult mothers during the same period. The demographic data of mothers and sick babies in both groups were recorded in the designed case record forms. Developmental assessment was done until two years of age. A total of 6,342 deliveries took place in Rajavithi Hospital during the study period of which 697 babies were born to teenage mothers. The incidence of teenage pregnancy was 10.99%. The number of sick babies from teenage mothers and adult mothers were 78 and 147 cases, respectively. There was a significantly higher mortality in the study group (7 cases, 9%) than the control group (4 cases, 2.7%). There was statistically significant difference in most of the demographic characteristics between the teenage and adult mothers except anemia, PROM and MSAF (meconium stain amniotic fluid). Although there was a trend of more cases of anemia and MSAF in teenage mothers than in adult mothers, there was no statistically significant difference. There was a shorter interval time from marriage to pregnancy in teen mothers than in adult mothers and a lower number of antenatal care visits with late antenatal care among the teenage mothers too. On comparing the data in infants

  12. Evaluation of lipid and glucose metabolism and cortisol and thyroid hormone levels in obese appropriate for gestational age (AGA) born and non-obese small for gestational age (SGA) born prepubertal Slovak children.

    Science.gov (United States)

    Blusková, Zuzana; Koštálová, Ludmila; Celec, Peter; Vitáriušová, Eva; Pribilincová, Zuzana; Maršálková, Marianna; Šemberová, Jana; Kyselová, Tatiana; Hlavatá, Anna; Kovács, László

    2014-07-01

    Obesity is the major determinant of metabolic syndrome. Being born small for gestational age (SGA) may be co-responsible. We aimed at evaluating the association between 1. obesity and 2. being born SGA and the presence of endocrine-metabolic abnormalities in prepubertal Slovak children. The study included 98 children, aged 3-10.9 years: 36 AGA-born obese children (OB), 31 SGA-born children (SGA) and 31 appropriate for gestational age born non-obese children (AGA). Fasting serum levels of glucose, total cholesterol, LDL, HDL, triglycerides, fT4, TSH, cortisol and insulin were determined. HOMA-IR was calculated. Personal data about birth weight and length and family history were collected. Actual anthropometric measurement was done. In every group, high prevalence of positive family history of metabolic disorder was found. In comparison with AGA children, OB children were taller (plevels and homeostasis model assessment for insulin resistance (HOMA-IR) (pcortisol levels (p=0.069) was noted. SGA-born children were shorter (plevels (plevels (p=0.085) and increased fT4 levels (pobese children and twice more metabolic abnormalities were present in SGA-born children in comparison with AGA-born children. SGA-born children are more prone to developing endocrine-metabolic abnormalities than non-obese children born AGA, but they are at less risk than obese AGA-born children. We should provide specialized care for obese children already in prepubertal age and pay attention to SGA-born children.

  13. Extended phase space thermodynamics and P-V criticality: Brans-Dicke-Born-Infeld vs. Einstein-Born-Infeld-dilaton black holes

    Energy Technology Data Exchange (ETDEWEB)

    Hendi, S.H. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P. O. Box 55134-441, Maragha (Iran, Islamic Republic of); Tad, R.M.; Armanfard, Z.; Talezadeh, M.S. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of)

    2016-05-15

    Motivated by a thermodynamic analogy of black holes and Van der Waals liquid/gas systems, in this paper, we study P-V criticality of both dilatonic Born-Infeld black holes and their conformal solutions, Brans-Dicke-Born-Infeld solutions. Due to the conformal constraint, we have to neglect the old Lagrangian of dilatonic Born-Infeld theory and its black hole solutions, and introduce a new one. We obtain spherically symmetric nonlinearly charged black hole solutions in both Einstein and Jordan frames and then we calculate the related conserved and thermodynamic quantities. After that, we extend the phase space by considering the proportionality of the cosmological constant and thermodynamical pressure. We obtain critical values of the thermodynamic coordinates through numerical methods and plot the relevant P-V and G-T diagrams. Investigation of the mentioned diagrams helps us to study the thermodynamical phase transition. We also analyze the effects of varying different parameters on the phase transition of black holes. (orig.)

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

    Science.gov (United States)

    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.

  15. Born to Lead? The Effect of Birth Order on Non-Cognitive Abilities

    OpenAIRE

    Black, Sandra E.; Grönqvist, Erik; Öckert, Björn

    2017-01-01

    We study the effect of birth order on personality traits among men using population data on enlistment records and occupations for Sweden. We find that earlier born men are more emotionally stable, persistent, socially outgoing, willing to assume responsibility, and able to take initiative than later-borns. In addition, we find that birth order affects occupational sorting; first-born children are more likely to be managers, while later-born children are more likely to be self-employed. We al...

  16. Global Mindset: An Entrepreneur's Perspective on the Born-Global Approach

    Directory of Open Access Journals (Sweden)

    Robert Poole

    2012-10-01

    Full Text Available The born-global approach calls for a startup to address the needs of a global market from inception. This approach provides an attractive alternative to the conventional staged approach to internationalization whereby a startup first operates in its home market and then enters one or more foreign markets sequentially. This article highlights the mindset change that an entrepreneur must make to move from the conventional staged approach to the born-global approach. The author of this article is an experienced entrepreneur and the article describes his own mindset change that occurred when enacting the born-global approach. The author uses his own experience and company as a case study to develop recommendations for other entrepreneurs who are evaluating the born-global approach to launch and grow a technology company.

  17. Perinatal outcomes in 375 children born after oocyte donation

    DEFF Research Database (Denmark)

    Malchau, Sara S; Loft, Anne; Larsen, Elisabeth C

    2013-01-01

    To describe perinatal outcomes in children born after oocyte donation (OD) compared with in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and spontaneous conception (SC).......To describe perinatal outcomes in children born after oocyte donation (OD) compared with in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and spontaneous conception (SC)....

  18. Survey of spatial distribution of vector-borne disease in ...

    African Journals Online (AJOL)

    Neighborhood dogs may act as reservoirs and disseminators of vector-borne diseases in urban areas. Accordingly, the aim of this study was to ascertain the health status and the vector-borne pathogens infecting dogs living in public areas with high levels of human movement in the city of Curitiba, southern Brazil.

  19. [Conflicts and vector-borne diseases

    DEFF Research Database (Denmark)

    Bygbjerg, Ib Christian

    2010-01-01

    Based on literature and personal experiences, vector-borne diseases and conflicts are reviewed. Simple rapid diagnostic tests for three important parasitoses are available. Resort is often made to case definitions and to presumptive treatment. Resistance is an emerging problem. Vaccines are still...

  20. Transport of Ixodid ticks and tick-borne pathogens by migratory birds.

    Directory of Open Access Journals (Sweden)

    Gunnar eHasle

    2013-09-01

    Full Text Available Birds, particularly passerines, can be parasitized by Ixodid ticks, which may be infected with tick-borne pathogens, like Borrelia spp., Babesia spp., Anaplasma, Rickettsia/Coxiella, and tick-borne encephalitis virus. The prevalence of ticks on birds varies over years, season, locality and different bird species. The prevalence of ticks on different species depends mainly on the degree of feeding on the ground. In Europe, the Turdus spp., especially the blackbird, Turdus merula, appears to be most important for harboring ticks. Birds can easily cross barriers, like fences, mountains, glaciers, desserts and oceans, which would stop mammals, and they can move much faster than the wingless hosts. Birds can potentially transport tick-borne pathogens by transporting infected ticks, by being infected with tick-borne pathogens and transmit the pathogens to the ticks, and possibly act as hosts for transfer of pathogens between ticks through co-feeding. Knowledge of the bird migration routes and of the spatial distribution of tick species and tick-borne pathogens is crucial for understanding the possible impact of birds as spreaders of ticks and tick-borne pathogens. Successful colonization of new tick species or introduction of new tick-borne pathogens will depend on suitable climate, vegetation and hosts. Although it has never been demonstrated that a new tick species, or a new tick pathogen, actually has been established in a new locality after being seeded there by birds, evidence strongly suggests that this could occur.

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

    Science.gov (United States)

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

    2016-04-01

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

  2. Born Globals - Is there Fire Behind the Smoke?

    DEFF Research Database (Denmark)

    Choquette, Eliane; Rask, Morten; Sala, Davide

    2017-01-01

    the first detailed account of Born Globals compared to proper control groups of other start-ups. Chiefly we investigate firm performance, which in turn permits interference on socioeconomic impact. We find that the occurrence of BGs is not specific to certain sectors, nor does their frequency change......Are Born Globals really different from firms with other start-up histories? We address this question based on a unique longitudinal data set that tracks all Danish manufacturing start-ups founded between 1994 and 2008 (23,201 firms). This novel application of register data allows us to provide...... in light of rapid ICT progress. However, we find that Born Globals have significantly higher turnover and employment levels as well as job growth rates. Moreover, they show a considerably wider market reach, but little to no productivity advantage compared to firms with less or later internationalization...

  3. Neurological development of children born to mothers after kidney transplantation.

    Science.gov (United States)

    Schreiber-Zamora, Joanna; Szpotanska-Sikorska, Monika; Drozdowska-Szymczak, Agnieszka; Czaplinska, Natalia; Pietrzak, Bronisława; Wielgos, Miroslaw; Kociszewska-Najman, Bozena

    2017-12-03

    Pregnancies after kidney transplantation are at high risk of complications such as preterm birth and foetal growth restriction. Until now, the impact of these factors on neurological development of children born to transplant mothers has not been established. A comparison of neurological examinations performed in 36 children of kidney transplant women (study group) and 36 children born to healthy mothers (control group). The children from both groups were born at a similar gestational age and in the similar time period from 12/1996 to 09/2012. Neurological examinations were performed from 07/2010 to 11/2013. Each examination was adjusted to the patient's age and performed after the neonatal period. Three years later children were re-consulted, if they presented neurological deviations or were less than 12 months old at the time of the first examination. Normal neurological development was found in 86% of children in both groups (p = .999). Mild neurological deviations were observed in four (11%) children born to kidney transplant mothers and in five (14%) children born to healthy mothers (p = .999). Moderate deviations were diagnosed in one premature child born to transplant mother, whose pregnancy was complicated with a severe preeclampsia and foetal growth restriction. In the study population, no severe neurological disorders were found. Almost all (8/10) children with neurological deviations were born prematurely in good general conditions. The neurological deviations observed in the first year of life were mild and transient. In children over 1 year of age, deviations were more pronounced and continued to maintain. The neurological development of children of kidney transplant women is similar to that of the general population and possible deviations seem to be the result of intrauterine hypotrophy and prematurity. Therefore, in clinical practice, it is necessary to plan post-transplant pregnancies especially in women at high risk of these complications.

  4. Balance in children born prematurely currently aged 6–7

    Directory of Open Access Journals (Sweden)

    Dziuba Ewa

    2017-12-01

    Full Text Available Study aim: Premature birth is one of the major problems of obstetrics, leading to numerous complications that are associated with prematurity, for instance balance disorders. The aim of the study was to assess the impact of premature birth on the ability to maintain balance in children commencing their school education. Material and methods: The study included children aged 6-7 years. The study group consisted of 59 children (31 girls and 28 boys, mean age 6.38 ± SD 0.73 born prematurely between 24 and 35 weeks of gestation. The control group consisted of 61 children (28 girls and 33 boys, mean age 6.42 ± 0.58 born at term. The research utilized standardized test tools - one-leg open-eyed and closed-eyed standing test, one-leg jumping test - and an original questionnaire survey. Results: The children born at term achieved better results in the majority of tests. The comparison of girls and boys born pre­maturely and at term showed no statistically significant difference between them in terms of dynamic balance, static balance or total balance control. The comparison of the tests performed on the right and left lower limb in prematurely born children showed no statistically significant differences. Conclusion: Premature birth affects the ability to maintain body balance. The results of the study indicate the need to develop coordination skills that shape body balance in prematurely born children.

  5. Mathematics ability and related skills in preschoolers born very preterm.

    Science.gov (United States)

    Hasler, Holly M; Akshoomoff, Natacha

    2017-12-12

    Children born very preterm (VPT) are at risk for academic, behavioral, and/or emotional problems. Mathematics is a particular weakness and better understanding of the relationship between preterm birth and early mathematics ability is needed, particularly as early as possible to aid in early intervention. Preschoolers born VPT (n = 58) and those born full term (FT; n = 29) were administered a large battery of measures within 6 months of beginning kindergarten. A multiple-mediation model was utilized to characterize the difference in skills underlying mathematics ability between groups. Children born VPT performed significantly worse than FT-born children on a measure of mathematics ability as well as full-scale IQ, verbal skills, visual-motor integration, phonological awareness, phonological working memory, motor skills, and executive functioning. Mathematics was significantly correlated with verbal skills, visual-motor integration, phonological processing, and motor skills across both groups. When entered into the mediation model, verbal skills, visual-motor integration, and phonological awareness were significant mediators of the group differences. This analysis provides insights into the pre-academic skills that are weak in preschoolers born VPT and their relationship to mathematics. It is important to identify children who will have difficulties as early as possible, particularly for VPT children who are at higher risk for academic difficulties. Therefore, this model may be used in evaluating VPT children for emerging difficulties as well as an indicator that if other weaknesses are found, an assessment of mathematics should be conducted.

  6. Impact of climate trends on tick-borne pathogen transmission

    Directory of Open Access Journals (Sweden)

    Agustin eEstrada-Pena

    2012-03-01

    Full Text Available Recent advances in climate research together with a better understanding of tick-pathogen interactions, the distribution of ticks and the diagnosis of tick-borne pathogens raise questions about the impact of environmental factors on tick abundance and spread and the prevalence and transmission of tick-borne pathogens. While undoubtedly climate plays a role in the changes in distribution and seasonal abundance of ticks, it is always difficult to disentangle factors impacting on the abundance of tick hosts from those exerted by human habits. All together, climate, host abundance and social factors may explain the upsurge of epidemics transmitted by ticks to humans. Herein we focused on tick-borne pathogens that affect humans with pandemic potential. Borrelia burgdorferi s.l. (Lyme disease, Anaplasma phagocytophilum (human granulocytic anaplasmosis and tick-borne encephalitis virus (tick-borne encephalitis are transmitted by Ixodes spp. Crimean-Congo hemorrhagic fever virus (Crimean-Congo hemorrhagic fever is transmitted by Hyalomma spp. In this review, we discussed how vector tick species occupy the habitat as a function of different climatic factors, and how these factors impact on tick survival and seasonality. How molecular events at the tick-pathogen interface impact on pathogen transmission is also discussed. Results from statistically and biologically derived models are compared to show that while statistical models are able to outline basic information about tick distributions, biologically derived models are necessary to evaluate pathogen transmission rates and understand the effect of climatic variables and host abundance patterns on pathogen transmission. The results of these studies could be used to build early alert systems able to identify the main factors driving the subtle changes in tick distribution and seasonality and the prevalence of tick-borne pathogens.

  7. A local network integrated into a balloon-borne apparatus

    Science.gov (United States)

    Imori, Masatosi; Ueda, Ikuo; Shimamura, Kotaro; Maeno, Tadashi; Murata, Takahiro; Sasaki, Makoto; Matsunaga, Hiroyuki; Matsumoto, Hiroshi; Shikaze, Yoshiaki; Anraku, Kazuaki; Matsui, Nagataka; Yamagami, Takamasa

    A local network is incorporated into an apparatus for a balloon-borne experiment. A balloon-borne system implemented in the apparatus is composed of subsystems interconnected through a local network, which introduces modular architecture into the system. The network decomposes the balloon-borne system into subsystems, which are similarly structured from the point of view that the systems is kept under the control of a ground station. The subsystem is functionally self-contained and electrically independent. A computer is integrated into a subsystem, keeping the subsystem under the control. An independent group of batteries, being dedicated to a subsystem, supplies the whole electricity of the subsystem. The subsystem could be turned on and off independently of the other subsystems. So communication among the subsystems needs to be based on such a protocol that could guarantee the independence of the individual subsystems. An Omninet protocol is employed to network the subsystems. A ground station sends commands to the balloon-borne system. The command is received and executed at the system, then results of the execution are returned to the ground station. Various commands are available so that the system borne on a balloon could be controlled and monitored remotely from the ground station. A subsystem responds to a specific group of commands. A command is received by a transceiver subsystem and then transferred through the network to the subsystem to which the command is addressed. Then the subsystem executes the command and returns results to the transceiver subsystem, where the results are telemetered to the ground station. The network enhances independence of the individual subsystems, which enables programs of the individual subsystems to be coded independently. Independence facilitates development and debugging of programs, improving the quality of the system borne on a balloon.

  8. Observational constraints on electromagnetic Born-Infeld cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Bretón, Nora; Montiel, Ariadna [Dpto. de Física, Centro de Investigación y de Estudios Avanzados del I.P.N., Apdo. 14–740, D.F. (Mexico); Lazkoz, Ruth, E-mail: nora@fis.cinvestav.mx, E-mail: amontiel@fis.cinvestav.mx [Dpto. de Física Teórica, Universidad del País Vasco, Apdo. 644, E-48080, Bilbao (Spain)

    2012-10-01

    The cosmological model consisting of an electromagnetic Born-Infeld (BI) field coupled to a Robertson-Walker geometry is tested with the standard probes of SNIa, GRBs and direct Hubble parameter. The analysis shows that the inclusion of the nonlinear electromagnetic component does not contribute in a significative way to the observed expansion. The BI electromagnetic matter is considered with an abundance of Ω{sub BI}, that our best fit leads to Ω{sub BI} = 0.037 when tested with SNIa and the Hubble parameter data (0.1 < z < 1.75); while when tested with GRBs the result is of Ω{sub BI} = 0.304, which may indicate that this electrodynamics was important at epochs close to the appearance of large structure (z ≈ 7), although this late result has not as much reliability as that corresponding to the first two probes, since we know that the dispersion in GRBs data is still considerable. In view of these results we can rule out the electromagnetic Born-Infeld matter as the origin of the present accelerated expansion, this conclusion concerns exclusively the Born-Infeld theory.

  9. Early working memory and maternal communication in toddlers born very low birth weight.

    Science.gov (United States)

    Lowe, Jean; Erickson, Sarah J; Maclean, Peggy; Duvall, Susanne W

    2009-04-01

    Early working memory is emerging as an important indicator of developmental outcome predicting later cognitive, behavioural and academic competencies. The current study compared early working memory in a sample of toddlers (18-22 months) born very low birth weight (VLBW; n = 40) and full term (n = 51) and the relationship between early working memory, mental developmental index (MDI), and maternal communication in both samples. Early working memory, measured by object permanence; Bayley mental developmental index; and maternal communication, coded during mother-toddler play interaction, were examined in 39 toddlers born VLBW and 41 toddlers born full term. Toddlers born VLBW were found to be 6.4 times less likely to demonstrate attainment of object permanence than were toddlers born full term, adjusting for age at testing. MDI and maternal communication were found to be positively associated with attainment of object permanence in the VLBW group only. The difference found in the early working memory performance of toddlers born VLBW, compared with those born full term, emphasizes the importance of assessing early working memory in at-risk populations, while the maternal communication finding highlights potential targets of intervention for improving working memory in toddlers born VLBW.

  10. Stability of a Tick-Borne Flavivirus in Milk

    OpenAIRE

    Offerdahl, Danielle K.; Clancy, Niall G.; Bloom, Marshall E.

    2016-01-01

    The tick-borne flaviviruses (TBFV) occur worldwide and the tick-borne encephalitis virus (TBEV) members of the group often cause severe, debilitating neurological disease in humans. Although the primary route of infection is through the bite of an infected tick, alimentary infection through the consumption of TBEV-contaminated dairy products is also well-documented and is responsible for some disease in endemic areas. Experimental infection of goats, cattle, and sheep with TBEV shows that the...

  11. Profile of tuberculosis among the foreign-born population in Japan, 2007–2014

    Science.gov (United States)

    Uchimura, Kazuhiro; Izumi, Kiyohiko; Ohkado, Akihiro; Ishikawa, Nobukatsu

    2016-01-01

    The proportion of foreign-born people among the newly notified tuberculosis (TB) patients has been increasing in recent years and potentially poses a new challenge to TB control in Japan. In this report, we analysed the data from the Japan TB surveillance system between 2007 and 2014 to gain an overview of the trends and characteristics of foreign-born TB patients in Japan. We found that the proportion of foreign-born TB patients was especially high among the younger age groups – 44.1% among the 20–29 years age group in 2014. The largest groups of foreign-born patients were from China and the Philippines; however, the number of those from Nepal and Viet Nam was on the rise. Students comprised the second largest professional category group for TB after regular workers, and its proportion increased over the study period. Compared to Japan-born TB patients, foreign-born patients were more likely to be diagnosed through routine medical check-ups. Treatment successes and patients still on treatment were significantly lower among foreign-born patients than their Japan-born counterparts; and transferred-out and unknown outcomes were higher. Our results indicated that distinctive subgroups within the foreign-born population in Japan, especially students and regular workers, might have a higher risk of developing TB. Measures to ensure early diagnosis and treatment adherence should be adapted to such populations. PMID:27508086

  12. Anisotropic effects of background fields on Born-Infeld electromagnetic waves

    International Nuclear Information System (INIS)

    Aiello, Matias; Bengochea, Gabriel R.; Ferraro, Rafael

    2007-01-01

    We show exact solutions of the Born-Infeld theory for electromagnetic plane waves propagating in the presence of static background fields. The non-linear character of the Born-Infeld equations generates an interaction between the background and the wave that changes the speed of propagation and adds a longitudinal component to the wave. As a consequence, in a magnetic background the ray direction differs from the propagation direction-a behavior resembling the one of a wave in an anisotropic medium. This feature could open up a way to experimental tests of the Born-Infeld theory

  13. Anisotropic effects of background fields on Born-Infeld electromagnetic waves

    Energy Technology Data Exchange (ETDEWEB)

    Aiello, Matias [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina) and Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina)]. E-mail: aiello@iafe.uba.ar; Bengochea, Gabriel R. [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina) and Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina)]. E-mail: gabriel@iafe.uba.ar; Ferraro, Rafael [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina) and Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina)]. E-mail: ferraro@iafe.uba.ar

    2007-01-22

    We show exact solutions of the Born-Infeld theory for electromagnetic plane waves propagating in the presence of static background fields. The non-linear character of the Born-Infeld equations generates an interaction between the background and the wave that changes the speed of propagation and adds a longitudinal component to the wave. As a consequence, in a magnetic background the ray direction differs from the propagation direction-a behavior resembling the one of a wave in an anisotropic medium. This feature could open up a way to experimental tests of the Born-Infeld theory.

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

    Science.gov (United States)

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

    2012-04-01

    Preterm-born children (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 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.

  15. The method of sections in molecular physics

    International Nuclear Information System (INIS)

    Natarajan, P.; Zygelman, B.

    1993-01-01

    In the standard Born-Oppenheimer theory the nuclear wave-function for a bound, rotating, di-atom system is described by the Wigner functions. Unlike the spherical harmonics, the Wigner functions exhibit cusp singularities at the poles of the space-fixed coordinate system. These singularities are identical to the ones encountered in the quantum mechanics treatment of a charged particle under the influence of a magnetic monopole. In the latter case the method of sectional was introduced to eliminate the singularities. The method of sections was also introduced in molecular physics. We discuss here, in detail, their properties and advantage of using this construction in molecular physics

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

    International Nuclear Information System (INIS)

    Aradi, Balint; Frauenheim, Thomas

    2015-01-01

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

  17. The Discovery of Anti-Matter The Autobiography of Carl David Anderson, the Youngest Man to Win the Nobel Prize

    CERN Document Server

    1999-01-01

    In 1936, at age 31, Carl David Anderson became the second youngest Nobel laureate for his discovery of antimatter when he observed positrons in a cloud chamber.He is responsible for developing rocket power weapons that were used in World War II.He was born in New York City in 1905 and was educated in Los Angeles. He served for many years as a physics professor at California Institute of Technology. Prior to Oppenheimer, Anderson was offered the job of heading the Los Alamos atomic bomb program but could not assume the role because of family obligations.He was a pioneer in studying cosmic rays

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

    Science.gov (United States)

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

    2015-07-14

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

  19. Addressing the Challenge of Molecular Change: An Interim Report

    Science.gov (United States)

    Levine, Raphael D.

    2018-04-01

    Invited by the editorial committee of the Annual Review of Physical Chemistry to "contribute my autobiography," I present it here, as I understand the term. It is about my parents, my mentors, my coworkers, and my friends in learning and the scientific problems that we tried to address. Courtesy of the editorial assistance of Annual Reviews, some of the science is in the figure captions and sidebars. I am by no means done: I am currently trying to fuse the quantitative rigor of physical chemistry with systems biology while also dealing with a post-Born-Oppenheimer regime in electronic dynamics and am attempting to instruct molecules to perform advanced logic.

  20. Functional outcome at school age of children born with gastroschisis

    NARCIS (Netherlands)

    Lap, Chiara C M M; Bolhuis, Sandra W; Van Braeckel, Koenraad J. A.; Reijneveld, Sijmen A.; Manten, Gwendolyn T. R.; Bos, Arend F.; Hulscher, Jan

    Objective: We aimed to determine motor, cognitive and behavioural outcomes of school aged children born with gastroschisis compared to matched controls. Study design: We compared outcomes of 16 children born with gastroschisis treated at the University Medical Center Groningen, the Netherlands,

  1. VECTOR BORNE TRANSMISSIBLE ZOONOSES IN MONTENEGRO

    Directory of Open Access Journals (Sweden)

    Gordana Mijovic

    2012-02-01

    Full Text Available Vector borne transmissible zoonoses are becoming more and more important in the group of emerging and re-emerging infections. We present the characteristics and actuality of this group of infectious diseases in Montenegro for the period 1998 - 2011. In examinations, standard epidemiological, clinical, serological, pathohistological diagnostic methods are employed. Natural conditions in Montenegro make it an important endemic area for more vector borne transmissible zoonoses. The changes of ecological characteristics, the vectors and infective agents, present the accidence for expansion and increasing importance of these infections in national pathology. According to the fact that it is an international port of nautical, continental and air traffic, Montenegro has responsibility for control and management of diseases belonging to the group of the travel and tropical diseases.

  2. Probabilities from entanglement, Born's rule from envariance

    International Nuclear Information System (INIS)

    Zurek, W.

    2005-01-01

    Full text: I shall discuss consequences of envariance (environment - assisted invariance) symmetry exhibited by entangled quantum states. I shall focus on the implications of envariance for the understanding of the origins and nature of ignorance, and, hence, for the origin of probabilities in physics. While the derivation of the Born's rule for probabilities (pk IykI2) is the principal accomplishment of this research, I shall explore the possibility that several other symptoms of the quantum - classical transition that are a consequence of decoherence can be justified directly by envariance -- i.e., without invoking Born's rule. (author)

  3. Born's reciprocity principle in stochastic phase space

    International Nuclear Information System (INIS)

    Prugovecki, E.

    1981-01-01

    It is shown that the application of Born's reciprocity principle to relativistic quantum mechanics in stochastic phase space (by the requirement that the proper wave functions of extended particles satisfy the Born-Lande as well as the Klein-Gordon equation) leads to the unique determination of these functions for any given value of their rms radius. The resulting particle propagators display not only Lorentz but also reciprocal invariance. This feature remains true even in the case of mass-zero particles, such as photons, when their localization is achieved by means of extended test particles whose proper wave functions obey the reciprocity principle. (author)

  4. Approximate symmetries of Hamiltonians

    Science.gov (United States)

    Chubb, Christopher T.; Flammia, Steven T.

    2017-08-01

    We explore the relationship between approximate symmetries of a gapped Hamiltonian and the structure of its ground space. We start by considering approximate symmetry operators, defined as unitary operators whose commutators with the Hamiltonian have norms that are sufficiently small. We show that when approximate symmetry operators can be restricted to the ground space while approximately preserving certain mutual commutation relations. We generalize the Stone-von Neumann theorem to matrices that approximately satisfy the canonical (Heisenberg-Weyl-type) commutation relations and use this to show that approximate symmetry operators can certify the degeneracy of the ground space even though they only approximately form a group. Importantly, the notions of "approximate" and "small" are all independent of the dimension of the ambient Hilbert space and depend only on the degeneracy in the ground space. Our analysis additionally holds for any gapped band of sufficiently small width in the excited spectrum of the Hamiltonian, and we discuss applications of these ideas to topological quantum phases of matter and topological quantum error correcting codes. Finally, in our analysis, we also provide an exponential improvement upon bounds concerning the existence of shared approximate eigenvectors of approximately commuting operators under an added normality constraint, which may be of independent interest.

  5. 8 CFR 289.3 - Recording the entry of certain American Indians born in Canada.

    Science.gov (United States)

    2010-01-01

    ... Indians born in Canada. 289.3 Section 289.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS AMERICAN INDIANS BORN IN CANADA § 289.3 Recording the entry of certain American Indians born in Canada. The lawful admission for permanent residence of an American Indian born in Canada...

  6. Dietary Sodium Intakes and Food Sources of Sodium in Canadian-Born and Asian-Born Individuals of Chinese Ethnicity at a Canadian University Campus

    Science.gov (United States)

    Yu, Yan Han; Farmer, Anna; Mager, Diana; Willows, Noreen

    2014-01-01

    Objective: To document the sodium intake and food sources of sodium of Canadian-born Chinese (CBC) and Asian-born Chinese (ABC) individuals at a Canadian university campus. Participants: Healthy adults aged 18-58 years originating from Canada, China, Hong Kong, or Taiwan were recruited from the University of Alberta (n = 40 CBC, n = 41 ABC)…

  7. DNA microarray technique for detecting food-borne pathogens

    Directory of Open Access Journals (Sweden)

    Xing GAO

    2012-08-01

    Full Text Available Objective To study the application of DNA microarray technique for screening and identifying multiple food-borne pathogens. Methods The oligonucleotide probes were designed by Clustal X and Oligo 6.0 at the conserved regions of specific genes of multiple food-borne pathogens, and then were validated by bioinformatic analyses. The 5' end of each probe was modified by amino-group and 10 Poly-T, and the optimized probes were synthesized and spotted on aldehyde-coated slides. The bacteria DNA template incubated with Klenow enzyme was amplified by arbitrarily primed PCR, and PCR products incorporated into Aminoallyl-dUTP were coupled with fluorescent dye. After hybridization of the purified PCR products with DNA microarray, the hybridization image and fluorescence intensity analysis was acquired by ScanArray and GenePix Pro 5.1 software. A series of detection conditions such as arbitrarily primed PCR and microarray hybridization were optimized. The specificity of this approach was evaluated by 16 different bacteria DNA, and the sensitivity and reproducibility were verified by 4 food-borne pathogens DNA. The samples of multiple bacteria DNA and simulated water samples of Shigella dysenteriae were detected. Results Nine different food-borne bacteria were successfully discriminated under the same condition. The sensitivity of genomic DNA was 102 -103pg/ μl, and the coefficient of variation (CV of the reproducibility of assay was less than 15%. The corresponding specific hybridization maps of the multiple bacteria DNA samples were obtained, and the detection limit of simulated water sample of Shigella dysenteriae was 3.54×105cfu/ml. Conclusions The DNA microarray detection system based on arbitrarily primed PCR can be employed for effective detection of multiple food-borne pathogens, and this assay may offer a new method for high-throughput platform for detecting bacteria.

  8. 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.

    Science.gov (United States)

    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.

  9. Lidar- and balloon-borne particle counter comparisons following recent volcanic eruptions

    Science.gov (United States)

    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.

  10. On generalized Born-Infeld electrodynamics

    International Nuclear Information System (INIS)

    Kruglov, S I

    2010-01-01

    The generalized Born-Infeld electrodynamics with two parameters is investigated. In this model the propagation of a linearly polarized laser beam in the external transverse magnetic field is considered. It was shown that there is the effect of vacuum birefringence, and we evaluate induced ellipticity. The upper bounds on the combination of parameters introduced from the experimental data of BRST and PVLAS Collaborations were obtained. When two parameters are equal to each other, we arrive at Born-Infeld electrodynamics and the effect of vacuum birefringence vanishes. We find the canonical and symmetrical Belinfante energy-momentum tensors. The trace of the energy-momentum tensor is not zero and the dilatation symmetry is broken. The four-divergence of the dilatation current is equal to the trace of the Belinfante energy-momentum tensor and is proportional to the parameter (with the dimension of the field strength) of the model. The dual symmetry is also broken in the model considered.

  11. Geometric approximation algorithms

    CERN Document Server

    Har-Peled, Sariel

    2011-01-01

    Exact algorithms for dealing with geometric objects are complicated, hard to implement in practice, and slow. Over the last 20 years a theory of geometric approximation algorithms has emerged. These algorithms tend to be simple, fast, and more robust than their exact counterparts. This book is the first to cover geometric approximation algorithms in detail. In addition, more traditional computational geometry techniques that are widely used in developing such algorithms, like sampling, linear programming, etc., are also surveyed. Other topics covered include approximate nearest-neighbor search, shape approximation, coresets, dimension reduction, and embeddings. The topics covered are relatively independent and are supplemented by exercises. Close to 200 color figures are included in the text to illustrate proofs and ideas.

  12. Light-by-Light Scattering Constraint on Born-Infeld Theory.

    Science.gov (United States)

    Ellis, John; Mavromatos, Nick E; You, Tevong

    2017-06-30

    The recent measurement by ATLAS of light-by-light scattering in LHC Pb-Pb collisions is the first direct evidence for this basic process. We find that it excludes a range of the mass scale of a nonlinear Born-Infeld extension of QED that is ≲100  GeV, a much stronger constraint than those derived previously. In the case of a Born-Infeld extension of the standard model in which the U(1)_{Y} hypercharge gauge symmetry is realized nonlinearly, the limit on the corresponding mass reach is ∼90  GeV, which, in turn, imposes a lower limit of ≳11  TeV on the magnetic monopole mass in such a U(1)_{Y} Born-Infeld theory.

  13. Assessment of Climate Change and Vector-borne Diseases in the United States

    Science.gov (United States)

    Monaghan, A. J.; Beard, C. B.; Eisen, R. J.; Barker, C. M.; Garofalo, J.; Hahn, M.; Hayden, M.; Ogden, N.; Schramm, P.

    2016-12-01

    Vector-borne diseases are illnesses that are transmitted by vectors, which include mosquitoes, ticks, and fleas. The seasonality, distribution, and prevalence of vector-borne diseases are influenced significantly by climate factors, primarily high and low temperature extremes and precipitation patterns. In this presentation we summarize key findings from Chapter 5 ("Vector-borne Diseases") of the recently published USGCRP Scientific Assessment of the Impacts of Climate Change on Human Health in the United States. Climate change is expected to alter geographic and seasonal distributions of vectors and vector-borne diseases, leading to earlier activity and northward range expansion of ticks capable of carrying the bacteria that cause Lyme disease and other pathogens, and influencing the distribution, abundance and prevalence of infection in mosquitoes that transmit West Nile virus and other pathogens. The emergence or reemergence of vector-borne pathogens is also likely.

  14. 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.

    Directory of Open Access Journals (Sweden)

    Shuyu Guo

    Full Text Available 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

  15. Type specimens of Pectinidae (Bivalvia) described by Ignaz von Born

    NARCIS (Netherlands)

    Dijkstra, H.H.

    2009-01-01

    Born described in two publications (1778, 1780) the molluscs in the collection of Empress Maria Theresa (1717-1780), now in the Natural History Museum at Vienna. In this paper the Pectinidae type material is described. Ten new species were introduced of which Argopecten nucleus (Born, 1778) and

  16. Tick-borne pathogen – Reversed and conventional discovery of disease

    Directory of Open Access Journals (Sweden)

    Ellen eTijsse Klasen

    2014-07-01

    Full Text Available Molecular methods have increased the number of known microorganisms associated with ticks significantly. Some of these newly identified microorganisms are readily linked to human disease while others are yet unknown to cause human disease. The face of tick-borne disease discovery has changed with more diseases now being discovered in a ‘reversed way’, detecting disease cases only years after the tick-borne microorganism was first discovered. Compared to the conventional discovery of infectious diseases, this order of discoveries presents researchers with new challenges. Especially estimating public health risks of such agents is challenging, as case definitions and diagnostic procedures may initially be missing. We discuss the advantages and shortcomings of molecular methods, serology, epidemiological studies that might be used to study some fundamental questions regarding newly identified tick-borne diseases. With increased tick-exposure and improved detection methods, more tick-borne microorganisms will be added to the list of pathogens causing disease in humans in future.

  17. Sparse approximation with bases

    CERN Document Server

    2015-01-01

    This book systematically presents recent fundamental results on greedy approximation with respect to bases. Motivated by numerous applications, the last decade has seen great successes in studying nonlinear sparse approximation. Recent findings have established that greedy-type algorithms are suitable methods of nonlinear approximation in both sparse approximation with respect to bases and sparse approximation with respect to redundant systems. These insights, combined with some previous fundamental results, form the basis for constructing the theory of greedy approximation. Taking into account the theoretical and practical demand for this kind of theory, the book systematically elaborates a theoretical framework for greedy approximation and its applications.  The book addresses the needs of researchers working in numerical mathematics, harmonic analysis, and functional analysis. It quickly takes the reader from classical results to the latest frontier, but is written at the level of a graduate course and do...

  18. Interpretation of second Born amplitudes in electron capture

    International Nuclear Information System (INIS)

    McGuire, J.H.; Simony, P.R.; Weaver, O.L.; Macek, J.

    1982-01-01

    Exact sound Born amplitudes for 1s-1s electron capture are presented and interpreted in terms of contributions from intermediate states off the energy shell and on the energy shell. The classical model of Thomas corresponds to two-step scattering via one particular on-shell intermediate state. In the high-velocity limit for 1s-1s capture, this on-shell intermediate state of the Thomas model accounts for one-half of the total cross section, i.e., the second Born cross section. The other half comes from off-energy-shell intermediate states near the on-shell Thomas state. Above 5 MeV both the off-shell and on-shell amplitudes have a simple structure near the Thomas peak. Below 1 MeV, contributions from a broader range of intermediate states are evident in the amplitudes. Although the contribution from the Thomas state is not large below 1 MeV, other second Born effects are significant

  19. Las Born Global: Empresas de Acelerada Internacionalización

    Directory of Open Access Journals (Sweden)

    Grettel Brenes Leiva

    2013-02-01

    Full Text Available Las born global son un grupo de pequeñas y medianasempresas emprendedoras que presentan unproceso de internacionalización acelerado, es decir,inician sus actividades comerciales en el mercadomundial justo apenas nacen o en un periodo muycercano a su nacimiento. Estas empresas ingresana los nuevos mercados obviando o se brincándosealgunas de las etapas del proceso tradicional de internacionalización,gradual o por etapas, conocidocomo “modelo Uppsala”. Son entes dinamizadoresde las economías que contribuyen en el desarrolloeconómico de los países, siempre y cuando se creael clima, las condiciones y la infraestructura indispensablepara que puedan alcanzar un desarrollosostenido de sus exportaciones. Este artículo intentacaracterizar a las born global partiendo de las definiciones,características, sostenibilidad y la selección ymodo de ingreso a los mercados globales.   ABSTRACT The born global is a group of small andmedium sized entrepreneurial companies that showan accelerated internationalization process, thatis, they start their commercial activity in worldmarkets just as they are born or in a period veryclose to their conception. These companies enternew markets paying no attention to, or disregardingsome of the steps of the traditional gradual orstepwise internationalization process known as the“Uppsala model”. They are dynamizing entities oftheir economies that contribute to the economicdevelopment of their countries, as long as the essentialoperating climate, conditions and infrastructure arecreated to allow them attain a sustained developmentin their exports. This article attempts to characterizethe born global companies starting from thedefinitions, characteristics, sustainability and theirchoice of ingress mode to global markets.

  20. Executive and Memory Function in Adolescents Born Very Preterm

    Science.gov (United States)

    Ment, Laura; Allan, Walter; Schneider, Karen; Vohr, Betty R.

    2011-01-01

    BACKGROUND: Many preterm children display school difficulties, which may be mediated by impairment in executive function and memory. OBJECTIVE: To evaluate executive and memory function among adolescents born preterm compared with term controls at 16 years. METHODS: A total of 337 of 437 (77%) adolescents born in 1989 to 1992 with a birth weight executive function and memory tasks. Multiple regression analyses were used to compare groups and to identify associations between selected factors and outcomes among preterm subjects. RESULTS: Adolescents born preterm, compared with term controls, showed deficits in executive function in the order of 0.4 to 0.6 SD on tasks of verbal fluency, inhibition, cognitive flexibility, planning/organization, and working memory as well as verbal and visuospatial memory. After exclusion of adolescents with neurosensory disabilities and full-scale IQ executive dysfunction, as measured with the Behavior Rating Inventory of Executive Function, on the Metacognition Index (odds ratio [OR]: 2.5 [95% confidence interval (CI): 1.2–5.1]) and the Global Executive Composite (OR: 4.2 [95% CI: 1.6–10.9]), but not on the Behavioral Regulation index (OR: 1.5 [95% CI: 0.7–3.5]). Among adolescents born preterm, severe brain injury on neonatal ultrasound and lower maternal education were the most consistent factors associated with poor outcomes. CONCLUSIONS: Even after exclusion of preterm subjects with significant disabilities, adolescents born preterm in the early 1990s were at increased risk of deficits in executive function and memory. PMID:21300680

  1. Dysconnectivity of neurocognitive networks at rest in very-preterm born adults

    Directory of Open Access Journals (Sweden)

    Thomas P. White

    2014-01-01

    Full Text Available Advances in neonatal medicine have resulted in a larger proportion of preterm-born individuals reaching adulthood. Their increased liability to psychiatric illness and impairments of cognition and behaviour intimate lasting cerebral consequences; however, the central physiological disturbances remain unclear. Of fundamental importance to efficient brain function is the coordination and contextually-relevant recruitment of neural networks. Large-scale distributed networks emerge perinatally and increase in hierarchical complexity through development. Preterm-born individuals exhibit systematic reductions in correlation strength within these networks during infancy. Here, we investigate resting-state functional connectivity in functional magnetic resonance imaging data from 29 very-preterm (VPT-born adults and 23 term-born controls. Neurocognitive networks were identified with spatial independent component analysis conducted using the Infomax algorithm and employing Icasso procedures to enhance component robustness. Network spatial focus and spectral power were not generally significantly affected by preterm birth. By contrast, Granger-causality analysis of the time courses of network activity revealed widespread reductions in between-network connectivity in the preterm group, particularly along paths including salience-network features. The potential clinical relevance of these Granger-causal measurements was suggested by linear discriminant analysis of topological representations of connection strength, which classified individuals by group with a maximal accuracy of 86%. Functional connections from the striatal salience network to the posterior default mode network informed this classification most powerfully. In the VPT-born group it was additionally found that perinatal factors significantly moderated the relationship between executive function (which was reduced in the VPT-born as compared with the term-born group and generalised partial

  2. Exploring workplace TB interventions with foreign-born Latino workers.

    Science.gov (United States)

    Eggerth, Donald E; Keller, Brenna M; Flynn, Michael A

    2018-05-15

    Persons born outside the United States are more likely to be diagnosed with tuberculosis disease (TB) than native-born individuals. Foreign-born Latinos at risk of TB may be difficult to reach with public health interventions due to cultural and institutional barriers. Workplaces employing large concentrations of foreign-born Latinos may be useful locations for TB interventions targeting this high-risk population. This study used a two-phase approach to investigate the feasibility of workplace TB interventions. The first phase investigated employer knowledge of TB and receptiveness to allowing TB interventions in their businesses through 5 structured interviews. The second phase investigated foreign-born workers' knowledge of TB and their receptiveness to receiving TB interventions in their places of employment through 12 focus groups stratified by gender and education. Phase 1: Only 1 of the 5 employers interviewed had a high level of knowledge about TB, and three had no knowledge other than that TB was a disease that involved coughing. They were receptive to workplace TB interventions, but were concerned about lost productivity and customers finding out if an employee had TB. Phase 2: There was no observed differences in responses between gender and between the bottom two education groups, so the final analysis took place between a gender-combined lower education group and higher education group. The higher education group tended to have knowledge that was more accurate and to view TB as a disease associated with poverty. The lower education group tended to have more misconceptions about TB and more often expressed concern that their employers would not support worksite interventions. The results from both phases indicate that more TB education is needed among both foreign-born Latino workers and their employers. Obstacles to implementing workplace TB interventions include knowledge, potential productivity loss, employer liability, and perceived customer response

  3. Born order study of {gamma}{sup *}{gamma}{sup *} {yields} {rho}{rho} at very high energy

    Energy Technology Data Exchange (ETDEWEB)

    Pire, B. [Ecole Polytechnique, 91 - Palaiseau (France). Centre de Physique Theorique; Szymanowski, L. [Soltan Institute for Nuclear Studies, Warsaw (Poland); Liege Univ. (Belgium); Wallon, S. [Paris-11 Univ., Lab. de Physique Theorique, 91 - Orsay (France)

    2005-07-01

    We calculate the cross-section for the diffractive exclusive process {gamma}{sub L}{sup *}(Q{sub 1}{sup 2}){gamma}{sub L}{sup *}(Q{sub 2}{sup 2}) {yields} {rho}{sub L}{sup 0}{rho}{sub L}{sup 0}, in view of its study in the future high energy e{sup +}e{sup -} linear collider. The Born order approximation of the amplitude is completely calculable in the hard region Q{sub 1}{sup 2},Q{sub 2}{sup 2} >> {lambda}{sup 2}(QCD). The resulting cross-section is large enough for this process to be measurable with foreseen luminosity and energy, for Q{sub 1}{sup 2} and Q{sub 2}{sup 2} in the range of a few GeV{sup 2}. (authors)

  4. Born Global from the Resource-Based Theory: A Case Study in Colombia

    Directory of Open Access Journals (Sweden)

    Alexander Tabares

    2015-07-01

    Full Text Available This paper describes how a born global firm goes into international market from inception at its early years. The objective of this paper is to analyze from the resource-based theory how a born global firm engages in international market. This empirical investigation has been carried out as an explorative single-case study, a high-tech firm, Digital Partner, based in Medellin, Antioquia. The main findings of the research show that organizational capabilities based on intellectual capital are crucial for the development of a born global. Thus, capabilities such as entrepreneurship, global vision, internationally market knowledge, learning management, IT capabilities, technological innovation, collaborative work, networks and customer orientation are recurrent and they correspond to other similar research results. Contributions of the study are both academic (for the advance of the research in born global field and practical (for the design of governmental policies to foster born global firms.

  5. Type 1 diabetes risk in children born to women with fertility problems

    DEFF Research Database (Denmark)

    Hargreave, Marie; Kjaer, Susanne K; Jørgensen, Marit E

    2016-01-01

    INTRODUCTION: While some studies have indicated that children born following fertility treatment are at an increased risk for insulin resistance and higher blood glucose levels, no study to date has investigated the risk of type 1 diabetes. In this large population-based cohort study we aim...... to assess the association between maternal fertility problems and the risk of type 1 diabetes in children. MATERIAL AND METHODS: Information on all children, born in Denmark from 1987 to 2010, was extracted from the Civil Registration System and linked with the Danish Infertility Cohort to identify maternal......%) were born to women with fertility problems. In all, 313 children born to women with fertility problems (0.36%) and 5176 children born to women without fertility problems (0.28%) were diagnosed with type 1 diabetes. The risk of type 1 diabetes was not affected by maternal fertility status (hazard ratio...

  6. Generalized Born-Infeld actions and projective cubic curves

    Energy Technology Data Exchange (ETDEWEB)

    Ferrara, S. [Department of Physics, CERN Theory Division, CH - 1211 Geneva 23 (Switzerland); INFN - Laboratori Nazionali di Frascati, Via Enrico Fermi 40, I-00044, Frascati (Italy); Porrati, M. [CCPP, Department of Physics, NYU, 4 Washington Pl., New York, NY, 10003 (United States); Sagnotti, A. [Department of Physics, CERN Theory Division, CH - 1211 Geneva 23 (Switzerland); Stora, R. [Department of Physics, CERN Theory Division, CH - 1211 Geneva 23 (Switzerland); Laboratoire d' Annecy-le-Vieux de Physique Theorique (LAPTH), F-74941, Annecy-le-Vieux, Cedex (France); Yeranyan, A. [INFN - Laboratori Nazionali di Frascati, Via Enrico Fermi 40, I-00044, Frascati (Italy); Centro Studi e Ricerche Enrico Fermi, Via Panisperna 89A, 00184, Roma (Italy)

    2015-04-01

    We investigate U(1){sup n} supersymmetric Born-Infeld Lagrangians with a second non-linearly realized supersymmetry. The resulting non-linear structure is more complex than the square root present in the standard Born-Infeld action, and nonetheless the quadratic constraints determining these models can be solved exactly in all cases containing three vector multiplets. The corresponding models are classified by cubic holomorphic prepotentials. Their symmetry structures are associated to projective cubic varieties. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Study of the climatic change impact on vector-borne diseases in West Africa: the case of tick-borne borreliosis and malaria

    International Nuclear Information System (INIS)

    Trape, J.F.

    2005-04-01

    Malaria and tick-borne borreliosis are the two first causes of morbidity due to vector-borne diseases in a large part of Sudan-sahelian West Africa. They are also the two tropical diseases which have been the most affected by climatic change in recent years. In the case of tick-borne borreliosis it has been shown in Senegal that the persistence of drought since the years 70 has been associated with a considerable extension of the geographic range of diseases and the vector tick A-sonrai, a species that was in the past limited to the Sahara and Sahel. In the case of malaria, drought has strongly reduced in these same regions of Africa the distribution, abundance and infection rate of Anopheline mosquitoes, but without any significant reduction of the burden of malaria for most populations concerned. The emergence and spread of Plasmodium falciparum resistance to antimalarial drugs only explain part of this phenomenon. (A.L.B.)

  8. The Born-Mayer-Huggins potential in high temperature superconductors

    Science.gov (United States)

    Singh, Hempal; Singh, Anu; Indu, B. D.

    2016-07-01

    The Born-Mayer-Huggins potential which has been found the best suitable potential to study the YBa2Cu3O7-δ type high temperature superconductors is revisited in a new framework. A deeper insight in it reveals that the Born-Mayer parameters for different interactions in high temperature superconductor are not simple quantities but several thermodynamic and spatial functions enter the problem. Based on the new theory, the expressions for pressure, bulk modulus and Born-Mayer parameters have been derived and it is established that these quantities depend upon Gruneisen parameter which is the measure of the strength of anharmonic effects in high temperature superconductors. This theory has been applied to a specific model YBa2Cu3O7-δ crystal for the purpose of numerical estimates to justify the new results.

  9. An investigation into the prevalence of water borne diseases in ...

    African Journals Online (AJOL)

    Water-borne diseases are the most prevalent infectious diseases in the developing countries especially in new settlements along the river. The present investigation was carried out to assess the prevalence rate of water-borne diseases among people residing near the left bank of River Ravi. This study has a descriptive ...

  10. Approximating distributions from moments

    Science.gov (United States)

    Pawula, R. F.

    1987-11-01

    A method based upon Pearson-type approximations from statistics is developed for approximating a symmetric probability density function from its moments. The extended Fokker-Planck equation for non-Markov processes is shown to be the underlying foundation for the approximations. The approximation is shown to be exact for the beta probability density function. The applicability of the general method is illustrated by numerous pithy examples from linear and nonlinear filtering of both Markov and non-Markov dichotomous noise. New approximations are given for the probability density function in two cases in which exact solutions are unavailable, those of (i) the filter-limiter-filter problem and (ii) second-order Butterworth filtering of the random telegraph signal. The approximate results are compared with previously published Monte Carlo simulations in these two cases.

  11. Primary damage in tungsten using the binary collision approximation, molecular dynamic simulations and the density functional theory

    International Nuclear Information System (INIS)

    De Backer, A; Sand, A; Ortiz, C J; Domain, C; Olsson, P; Berthod, E; Becquart, C S

    2016-01-01

    The damage produced by primary knock-on atoms (PKA) in W has been investigated from the threshold displacement energy (TDE) where it produces one self interstitial atom–vacancy pair to larger energies, up to 100 keV, where a large molten volume is formed. The TDE has been determined in different crystal directions using the Born–Oppenheimer density functional molecular dynamics (DFT-MD). A significant difference has been observed without and with the semi-core electrons. Classical MD has been used with two different empirical potentials characterized as ‘soft’ and ‘hard’ to obtain statistics on TDEs. Cascades of larger energy have been calculated, with these potentials, using a model that accounts for electronic losses (Sand et al 2013 Europhys. Lett. 103 46003). Two other sets of cascades have been produced using the binary collision approximation (BCA): a Monte Carlo BCA using SDTrimSP (Eckstein et al 2011 SDTrimSP: Version 5.00. Report IPP 12/8) (similar to SRIM www.srim.org) and MARLOWE (RSICC Home Page. (https://rsicc.ornl.gov/codes/psr/psr1/psr-137.html) (accessed May, 2014)). The comparison of these sets of cascades gave a recombination distance equal to 12 Å which is significantly larger from the one we reported in Hou et al (2010 J. Nucl. Mater. 403 89) because, here, we used bulk cascades rather than surface cascades which produce more defects (Stoller 2002 J. Nucl. Mater. 307 935, Nordlund et al 1999 Nature 398 49). Investigations on the defect clustering aspect showed that the difference between BCA and MD cascades is considerably reduced after the annealing of the cascade debris at 473 K using our Object Kinetic Monte Carlo model, LAKIMOCA (Domain et al 2004 J. Nucl. Mater. 335 121). (paper)

  12. General Rytov approximation.

    Science.gov (United States)

    Potvin, Guy

    2015-10-01

    We examine how the Rytov approximation describing log-amplitude and phase fluctuations of a wave propagating through weak uniform turbulence can be generalized to the case of turbulence with a large-scale nonuniform component. We show how the large-scale refractive index field creates Fermat rays using the path integral formulation for paraxial propagation. We then show how the second-order derivatives of the Fermat ray action affect the Rytov approximation, and we discuss how a numerical algorithm would model the general Rytov approximation.

  13. Rapid Identification of Vector-Borne Flaviviruses by Mass Spectrometry

    Science.gov (United States)

    2010-02-01

    Eastern, and Siberian subtypes [9]. Several tick-borne flaviviruses can also cause hemorrhagic disease. Important examples of these viruses include...assay. Identical base compositions within a column are the same color. Unique base compositions are shown with white backgrounds. (For interpretation...States, 1999e2005. Vector Borne Zoonotic Dis 2008;8:733e40. [18] Hofstadler SA, Sampath R, Blyn LB, Eshoo MW, Hall TA, Jiang Y, et al. TIGER : the

  14. The second Born approximation of electron–argon elastic scattering ...

    Indian Academy of Sciences (India)

    [7] D Nehari, J Holmes, K M Dunseath and M Terao-Dunseath, J. Phys. B43, 025203 (2010). [8] B A Harak, L Ladino and N L S Martin, Bull. Am. Phys. Soc. 55, 5 (2010). [9] M Ghalim and F Mastour, J. Phys. B32, 3783 (1999). [10] S T Zhang, J Chen and S M Li, Can. J. Phys. 80, 969 (2002). Pramana – J. Phys., Vol. 78, No.

  15. Long-term cognitive outcomes of infants born moderately and late preterm.

    Science.gov (United States)

    Odd, David Edward; Emond, Alan; Whitelaw, Andrew

    2012-08-01

    To investigate whether infants born late preterm have poorer cognitive outcomes than term-born infants. A cohort study based on the Avon Longitudinal Study of Parents and Children. Cognitive measures were assessed between the ages of 8 and 11 years. Exposure groups were defined as moderate/late preterm (32-36 weeks' gestation) or term (37-42 wk). Regression models were used to investigate the association between gestational age and IQ. Seven hundred and forty-one infants (5.4% of total eligible population; 422 males, 319 females; mean (SD) birthweight 2495 g [489]) were born between 32 and 36 weeks' gestation. The analysis was based on 6957 infants with IQ data at age 11 (50% of eligible infants). In the adjusted model, children born moderately and late preterm had similar IQ scores to peers born at term (mean difference [95% confidence interval] -0.18 [-1.88 to 1.52]). However, the preterm infants had a higher risk of having special educational needs at school (odds ratio 1.56 [1.18-2.07]). Despite an increased risk of special educational needs, there is little evidence of a reduction in IQ, memory, or attention measures at school age in children born between 32 and 36 weeks' gestation. Although interpretation is limited by the amount of missing data, further work is needed to identify why these infants have increased educational needs. © The Authors. Developmental Medicine & Child Neurology © 2012 Mac Keith Press.

  16. Visuospatial perception in children born preterm with no major neurological disorders.

    Science.gov (United States)

    Butcher, Phillipa R; Bouma, Anke; Stremmelaar, Elisabeth F; Bos, Arend F; Smithson, Michael; Van Braeckel, Koenraad N J A

    2012-11-01

    Many investigations have found deficits in visuospatial perception in children born preterm, however, it is not clear whether the deficits are specific to visuospatial perception or the consequences of deficits in other functional areas, which often accompany preterm birth. This study investigated whether children born preterm show a specific deficit in visuospatial perception. Fifty-six 7- to 11-year-old preterm born children (gestational age children completed four computerized tasks tapping different levels and types of visuospatial perception. Accuracy and speed of responses were recorded. Task formats were designed to reduce demands on attentional deployment. Measures of intelligence and parental education were included in the analysis. Children born preterm performed less accurately and/or less rapidly on all tasks. Their poorer performance did not reflect differences in speed-accuracy trade-off. Parental education and IQ, both significantly lower in the preterm children, contributed positively to performance on all tasks. IQ mediated the association between preterm birth and visuospatial performance on the most cognitively demanding task. Children born preterm performed more poorly than full-term controls on four visuospatial perceptual tasks. Although intelligence and parental education were also associated with performance, preterm birth contributed independently of these factors on three of four tasks. Many children born preterm are thus multiply disadvantaged on visuospatial tasks: the lower IQ scores and parental educational levels frequently found in this group increase the deficit associated with preterm birth. (c) 2012 APA, all rights reserved.

  17. Exact solutions of Lovelock-Born-Infeld black holes

    International Nuclear Information System (INIS)

    Aiello, Matias; Ferraro, Rafael; Giribet, Gaston

    2004-01-01

    The exact five-dimensional charged black hole solution in Lovelock gravity coupled to Born-Infeld electrodynamics is presented. This solution interpolates between the Hoffmann black hole for the Einstein-Born-Infeld theory and other solutions in the Lovelock theory previously studied in the literature. It is shown how the conical singularity of the metric around the origin can be removed by a proper choice of the black hole parameters. The differences existing with the Reissner-Nordstroem black holes are discussed. In particular, we show the existence of charged black holes with a unique horizon

  18. The Alliance Capability of Technology-Based Born Globals

    DEFF Research Database (Denmark)

    Oxtorp, Liliya Altshuler; Elg, Ulf

    2015-01-01

    A detailed investigation of the aspects comprising the alliance capability of technology-based born globals. Alliance capability is regarded as a set of organizational skills necessary from the decision to search for a partner for a technology collaboration, which may also involve a marketing...... and risks of collaborating with MNEs.Methodology: A longitudinal process study of a Danish technology born global with three embedded cases of its R&D and marketing alliances with Asian MNEs.Findings: The organisational skills comprising the alliance capability are defined to be internal and external...

  19. The use of car-borne gamma-ray spectrometric survey in a basin

    International Nuclear Information System (INIS)

    Liu Tengyao; Lu Shili; Luo Zongquan.

    1985-01-01

    This paper describes the geological results in a basin in the Inner Mongolia which were obtained by using our newly-developed and assembled car-borne gamma-ray spectrometric system. Combined with the work of regional geology and remote sensing, five relatively favourable uranium zones were located within the working area. The field procedures of car-borne gamma-ray spectrometry for less rigid regions is discussed. The gamma-ray spectrometric profiling is mainly used for regional reconnaissance. In the case of enhanced anomalious radioactivity the profiling with varying directions is adopted and the data are plotted on scale 1:50000 topographic map. It is suggested that the car-borne gamma-ray spectrometric system can be calibrated both by the pads specified for portable spectrometers and by testing site when the calibration facility for the car-borne gamma-ray spectrometric system is not available. The effect of rainfall on car-borne gamma-ray spectrometric survey and the simplified field qualitative determination of U-Ra disequilibrium are also briefly discussed

  20. Brothers and reduction of the birth weight of later-born siblings

    DEFF Research Database (Denmark)

    Nielsen, Henriette Svarre; Mortensen, Laust; Nygaard, Ulrikka

    2008-01-01

    It has been speculated whether maternal immune responses against male-specific minor histocompatibility (H-Y) antigens affect pregnancies negatively. This study explores, on a population level, whether previous births of boys compared with girls are associated with a decrease in birth weight...... of later-born siblings. The population was identified in the Danish Birth Registry and consisted of all Danish women who gave birth to their first-born singleton from 1980 to 1998. The women were followed until 2004, and their subsequent births were recorded. A total of 545,839 second- to fourth......-born children were identified. The authors used linear regression to analyze the association between sex of preceding children and birth weight of subsequent siblings. Brothers compared with sisters reduced the birth weight of later-born siblings. One or two brothers, respectively, reduced the mean birth weight...

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

    Science.gov (United States)

    Lesiuk, Michał; Balawender, Robert; Zachara, Janusz

    2012-01-21

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

  2. Can two-photon spectroscopy of H{sub 2}{sup +} or HD{sup +} allow a new determination of m{sub p}/m{sub e} ratio?; La spectroscopie a deux photons de H{sub 2}{sup +} ou HD{sup +} peut-elle permettre une nouvelle determination de m{sub p}/m{sub e}?

    Energy Technology Data Exchange (ETDEWEB)

    Karr, J.Ph.; Kilic, S.; Hilico, L. [Universite Pierre et Marie Curie, Lab. Kastler Brossel, 75 - Paris (France); Evry Val d' Essonne Univ., Dept. de Physique, 91 (France)

    2006-10-15

    We present an exact calculation of the non-relativistic energies and wavefunctions of the J=1 states of the HD{sup +} molecular ion. The energies are obtained with a high accuracy of 10{sup -14} u.a, that is an improvement of several orders of magnitude with respects to previous calculations. Then we compute the 2-photon transition probabilities between J=0 states. Finally we extend our study to transitions between higher J states by using the Born-Oppenheimer approximate expression of the transition probability. The HD{sup +} molecular ion appears to be a better candidate than H{sub 2}{sup +} for a 2-photon spectroscopy experiment aimed at determining the m{sub p}/m{sub e} ratio because of the existence of an exceptionally intense 2-photon transition: J=1, v=0 {yields} J=1, v= 2 at 5.369 {mu}m. Furthermore 2 experimental factors support this choice, first the initial level of the transition will be 10 times as populated as in the case of H{sub 2}{sup +}. Secondly, laser sources in the range 5-6 {mu}m are more powerful than those in the range 9-10 {mu}m required for H{sub 2}{sup +}.

  3. Toward prethreshold gate-based quantum simulation of chemical dynamics: using potential energy surfaces to simulate few-channel molecular collisions

    Science.gov (United States)

    Sornborger, Andrew T.; Stancil, Phillip; Geller, Michael R.

    2018-05-01

    One of the most promising applications of an error-corrected universal quantum computer is the efficient simulation of complex quantum systems such as large molecular systems. In this application, one is interested in both the electronic structure such as the ground state energy and dynamical properties such as the scattering cross section and chemical reaction rates. However, most theoretical work and experimental demonstrations have focused on the quantum computation of energies and energy surfaces. In this work, we attempt to make the prethreshold (not error-corrected) quantum simulation of dynamical properties practical as well. We show that the use of precomputed potential energy surfaces and couplings enables the gate-based simulation of few-channel but otherwise realistic molecular collisions. Our approach is based on the widely used Born-Oppenheimer approximation for the structure problem coupled with a semiclassical method for the dynamics. In the latter the electrons are treated quantum mechanically but the nuclei are classical, which restricts the collisions to high energy or temperature (typically above ≈ 10 eV). By using operator splitting techniques optimized for the resulting time-dependent Hamiltonian simulation problem, we give several physically realistic collision examples, with 3-8 channels and circuit depths < 1000.

  4. Antidiabetic Theory of Superconducting State Transition: Phonons and Strong Electron Correlations the Old Physics and New Aspects

    International Nuclear Information System (INIS)

    Banacky, P.

    2010-01-01

    Complex electronic ground state of molecular and solid state system is analyzed on the ab initio level beyond the adiabatic Born-Oppenheimer approximation (BOA). The attention is focused on the band structure fluctuation (BSF) at Fermi level, which is induced by electron-phonon coupling in superconductors, and which is absent in the non-superconducting analogues. The BSF in superconductors results in breakdown of the adiabatic BOA. At these circumstances, chemical potential is substantially reduced and system is stabilized (effect of nuclear dynamics) in the anti adiabatic state at broken symmetry with a gap(s) in one-particle spectrum. Distorted nuclear structure has fluxional character and geometric degeneracy of the anti adiabatic ground state enables formation of mobile bipolarons in real space. It has been shown that an effective attractive e-e interaction (Cooper-pair formation) is in fact correction to electron correlation energy at transition from adiabatic into anti adiabatic ground electronic state. In this respect, Cooper-pair formation is not the primary reason for transition into superconducting state, but it is a consequence of anti adiabatic state formation. It has been shown that thermodynamic properties of system in anti adiabatic state correspond to thermodynamics of superconducting state. Illustrative application of the theory for different types of superconductors is presented.

  5. The boomerang effect in electron-hydrogen molecule scattering as determined by time-dependent calculations

    Science.gov (United States)

    Ben-Asher, Anael; Moiseyev, Nimrod

    2017-05-01

    The appearance of oscillations in the energy-dependent cross sections of the vibrational excitation ν =0 →ν ≥3 of the hydrogen molecule in its electronic ground state as predicted by Mündel, Berman, and Domcke [Phys. Rev. A 32, 181 (1985)] was confirmed in the electron scattering experiments by Allan [J. Phys. B: At. Mol. Phys. 18, L451 (1985)]. These unusual structures were obtained in spite of the extremely short lifetime of H2- in its ro-vibrational states. Based on the standard (Hermitian) time-independent scattering calculations, Horáček et al. [Phys. Rev. A 73, 022701 (2006)] associated these oscillations with the boomerang effect. Here, we show the boomerang effect as developed in time, based on our time-dependent nuclear wavepacket (WP) calculations. The nuclear WP dynamics of H2- is determined using the non-Hermitian quantum mechanics (NH-QM) which enables the use of the Born-Oppenheimer approximation with complex potential energy surfaces. This NH-QM approach, which enables us the association of the nuclear WP dynamics as obtained from the complex potential energy curve of H2- with the evolution of cross section in time, can enlighten the dynamics in other scattering experiments.

  6. Bone-borne palatal distraction to correct the constricted cleft maxilla.

    Science.gov (United States)

    Vyas, Raj M; Jarrahy, Reza; Sisodia, Manisha; Jourabchi, Natanel; Wasson, Kristy L; Bradley, James P

    2009-05-01

    Transverse maxillary hypoplasia, with or without cleft deformity, is typically treated with orthodontic expansion. However, the management of those patients who present later in life with severe uncorrected deformities or who have failed prior orthodontic care remains controversial. Tooth-borne palatal expanders have limitations in this subset of patients with scarred, constricted cleft palate. In this study, we assess the efficacy and safety of using a bone-borne palatal distraction device as an alternative treatment for this difficult subset of patients. Older children with a constricted maxilla who previously had unilateral or bilateral cleft lip and palate repairs and failed orthodontic expansion were included in the study (n = 15). Patients underwent Le Fort I corticotomy with placement of the bone-borne distraction device, expansion at a rate of 0.5 mm/d, and subsequent alveolar bone grafting. Preoperative and follow-up maxillary impressions were compared with assessed improvements in intermolar distance, intercanine distance, alveolar cleft width, and total palatal area. In addition, a small group of noncleft patients with constricted maxillas was treated with bone-borne palatal distraction without a corticotomy (n = 4). The mean amount of distraction in all patients was 14.1 mm, with a follow-up period of 19 months (range, 8-30 months). The average increase in intermolar distance was 8.4 mm, intercanine distance increased by an average of 9.5 mm, and palate surface areas were increased by a mean of 28.9 mm2. Relapse was between 4% and 7%, and all patients underwent subsequent alveolar bone grafting. In addition, the noncleft patients successfully underwent bone-borne palatal distraction without a corticotomy, with a 4% to 5% relapse. Rapid palatal expansion using a bone-borne distraction device in cleft patients with transverse maxillary hypoplasia who have failed nonsurgical orthodontic expansion provides adequate expansion necessary for alveolar bone

  7. Genetic recombination of tick-borne flaviviruses among wild-type strains.

    Science.gov (United States)

    Norberg, Peter; Roth, Anette; Bergström, Tomas

    2013-06-05

    Genetic recombination has been suggested to occur in mosquito-borne flaviviruses. In contrast, tick-borne flaviviruses have been thought to evolve in a clonal manner, although recent studies suggest that recombination occurs also for these viruses. We re-analyzed the data and found that previous conclusions on wild type recombination were probably falsely drawn due to misalignments of nucleotide sequences, ambiguities in GenBank sequences, or different laboratory culture histories suggestive of recombination events in laboratory. To evaluate if reliable predictions of wild type recombination of tick-borne flaviviruses can be made, we analyzed viral strains sequenced exclusively for this study, and other flavivirus sequences retrieved from GenBank. We detected genetic signals supporting recombination between viruses within the three clades of TBEV-Eu, TBEV-Sib and TBEV-Fe, respectively. Our results suggest that the tick-borne encephalitis viruses may undergo recombination under natural conditions, but that geographic barriers restrict most recombination events to involve only closely genetically related viruses. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. SPACE-BORNE LASER ALTIMETER GEOLOCATION ERROR ANALYSIS

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2018-05-01

    Full Text Available This paper reviews the development of space-borne laser altimetry technology over the past 40 years. Taking the ICESAT satellite as an example, a rigorous space-borne laser altimeter geolocation model is studied, and an error propagation equation is derived. The influence of the main error sources, such as the platform positioning error, attitude measurement error, pointing angle measurement error and range measurement error, on the geolocation accuracy of the laser spot are analysed by simulated experiments. The reasons for the different influences on geolocation accuracy in different directions are discussed, and to satisfy the accuracy of the laser control point, a design index for each error source is put forward.

  9. The Emergence of `Power with': The Case of a Born Global Organization

    Science.gov (United States)

    Yan, Lin; Panteli, Niki

    Thanks to the advancement of Information and Communications Technologies, the past decade has seen the rise of Born Global organizations (Rennie, 1993; Oviatt and McDougall, 1994; Karra and Philips, 2004; Zahra, 2005). Broadly defined as ‘business organizations that, right from inception, seek to derive significant competitive advantages from the use of resources and the sales of outputs in multiple countries’ (Oviatt and McDougall, 1994: 49), Born Global organizations are small, young, and internationally dispersed. While sharing the characteristics of ‘smallness’ and ‘newness’ of Small- and Medium-sized Enterprises (SMEs), Born Global organizations also bear ‘foreignness’, similar to that of Multinational Corporations (Zahra, 2005). Born Globals therefore need to strike a balance between ‘global reach’ and ‘local touch’ as in Multinational Corporations (Bartlett and Ghoshal, 1989); yet they have to do so with scare resources and organizational uncertainty similar to SMEs, and with ‘lean’ and ‘mean’ communications afforded by ICT (e.g. Sproull and Kiesler, 1986). This study is an initial attempt to untangle the combined challenges in Born Globals’ innovative way of management. Through a longitudinal case study, we aim to explore the issue of power in a Born Global’s endeavour to manage its global knowledge via technology mediation.

  10. Vector-borne diseases

    DEFF Research Database (Denmark)

    More, Simon J.; Bicout, Dominique; Bøtner, Anette

    2017-01-01

    After a request from the Europea n Commission, EFSA’s Panel on Animal Health and Welfaresummarised the main characteristics of 36 vector-borne disease s (VBDs) in 36 web-based storymaps.The risk of introduction in the EU through movement of livestock or pets was assessed for eac h of the36 VBDs......-agents for which the rate of introduction wasestimated to be very low, no further asse ssments were made. Due to the uncertainty related to someparameters used for the risk assessment or the instable or unpredictability disease situation in some ofthe source regions, it is recommended to update the assessment when...

  11. The shape of things to come? Obesity prevalence among foreign-born vs. US-born Mexican youth in California.

    Science.gov (United States)

    Buttenheim, Alison M; Pebley, Anne R; Hsih, Katie; Chung, Chang Y; Goldman, Noreen

    2013-02-01

    Obesity among the Mexican-origin adult population in the US has been associated with longer stays in the US and with being US- vs. Mexican-born, two proxies for acculturation. This pattern is less clear for Mexican-origin children and young adults: recent evidence suggests that it may be reversed, with foreign-born Mexican youth in the US at higher risk of obesity than their US-born Mexican-American counterparts. The objective of this study is to evaluate the hypothesis that the immigrant advantage in obesity prevalence for Mexican-origin populations in the US does not hold for children and young adults. We use data from the Los Angeles Family and Neighborhood Survey (N = 1143) and the California Health Interview Survey (N = 25,487) for respondents ages 4-24 to calculate the odds of overweight/obesity by ethnicity and nativity. We find support for the hypothesis that overweight/obesity prevalence is not significantly lower for first-generation compared to second- and third-generation Mexican-origin youth. Significantly higher obesity prevalence among the first generation was observed for young adult males (ages 18-24) and adolescent females (ages 12-17). The previously-observed protective effect against obesity risk among recent adult immigrants does not hold for Mexican-origin youth. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Discussion of electron capture theories for ion-atom collisions at high energies

    Energy Technology Data Exchange (ETDEWEB)

    Miraglia, J E [Instituto de Astronomia y Fisica del Espacio, Buenos Aires (Argentina); Piacentini, R D [Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Rivarola, R D [Rosario Univ. Nacional (Argentina). Dept. de Fisica; Salin, A [Bordeaux-1 Univ., 33 - Talence (France)

    1981-03-14

    Different theories of charge exchange processes in ion-atom collisions at high energies for the H/sup +/-H system are considered. Large discrepancies are found in the differential cross sections obtained from the various models. The validity of Dettmann's peaking approximation is analysed by comparison with exact values for the first- and second-order Oppenheimer-Brinkman-Kramers (OBK 1 and OBK 2) theories. It is also shown that for energies up to a few MeV the OBK 2 differential cross sections are higher than the corresponding OBK 1 ones. Total cross sections in the OBK 2 approximation are given.

  13. Approximation techniques for engineers

    CERN Document Server

    Komzsik, Louis

    2006-01-01

    Presenting numerous examples, algorithms, and industrial applications, Approximation Techniques for Engineers is your complete guide to the major techniques used in modern engineering practice. Whether you need approximations for discrete data of continuous functions, or you''re looking for approximate solutions to engineering problems, everything you need is nestled between the covers of this book. Now you can benefit from Louis Komzsik''s years of industrial experience to gain a working knowledge of a vast array of approximation techniques through this complete and self-contained resource.

  14. The Chinese-born immigrant infant feeding and growth hypothesis

    Directory of Open Access Journals (Sweden)

    Kristy A. Bolton

    2016-10-01

    Full Text Available Abstract Background Rapid growth in the first six months of life is a well-established risk factor for childhood obesity, and child feeding practices (supplementation or substitution of breast milk with formula and early introduction of solids have been reported to predict this. The third largest immigrant group in Australia originate from China. Case-studies reported from Victorian Maternal and Child Health nurses suggest that rapid growth trajectories in the infants of Chinese parents is common place. Furthermore, these nurses report that high value is placed by this client group on rapid growth and a fatter child; that rates of breastfeeding are low and overfeeding of infant formula is high. There are currently no studies which describe infant growth or its correlates among this immigrant group. Presentation of hypothesis We postulate that in Australia, Chinese-born immigrant mothers will have different infant feeding practices compared to non-immigrant mothers and this will result in different growth trajectories and risk of overweight. We present the Chinese-born immigrant infant feeding and growth hypothesis - that less breastfeeding, high formula feeding and early introduction of solids in infants of Chinese-born immigrant mothers living in Australia will result in a high protein intake and subsequent rapid growth trajectory and increased risk of overweight and obesity. Testing the hypothesis Three related studies will be conducted to investigate the hypothesis. These will include two quantitative studies (one cross-sectional, one longitudinal and a qualitative study. The quantitative studies will investigate differences in feeding practices in Chinese-born immigrant compared to non-immigrant mothers and infants; and the growth trajectories over the first 3.5 years of life. The qualitative study will provide more in-depth understanding of the influencing factors on feeding practices in Chinese-born immigrant mothers. Implications of the

  15. On a new approach for constructing wormholes in Einstein-Born-Infeld gravity

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Young [Kunsan National University, Department of Physics, Kunsan (Korea, Republic of); Park, Mu-In [Sogang University, Research Institute for Basic Science, Seoul (Korea, Republic of)

    2016-11-15

    We study a new approach for the wormhole construction in Einstein-Born-Infeld gravity, which does not require exotic matters in the Einstein equation. The Born-Infeld field equation is not modified by coordinate independent conditions of continuous metric tensor and its derivatives, even though the Born-Infeld fields have discontinuities in their derivatives at the throat in general. We study the relation of the newly introduced conditions with the usual continuity equation for the energy-momentum tensor and the gravitational Bianchi identity. We find that there is no violation of energy conditions for the Born-Infeld fields contrary to the usual approaches. The exoticity of the energy-momentum tensor is not essential for sustaining wormholes. Some open problems are discussed. (orig.)

  16. Constraining Born-Infeld-like nonlinear electrodynamics using hydrogen's ionization energy

    Energy Technology Data Exchange (ETDEWEB)

    Akmansoy, P.N. [Universidade Federal do Rio Grande do Norte, Departamento de Fisica Teorica e Experimental, Natal (Brazil); Medeiros, L.G. [Universidade Estadual Paulista, Instituto de Fisica Teorica, Sao Paulo, SP (Brazil); Universidade Federal do Rio Grande do Norte, Escola de Ciencia e Tecnologia, Natal, RN (Brazil)

    2018-02-15

    In this work, the hydrogen's ionization energy was used to constrain the free parameter b of three Born-Infeld-like electrodynamics namely Born-Infeld itself, Logarithmic electrodynamics and Exponential electrodynamics. An analytical methodology capable of calculating the hydrogen ground state energy level correction for a generic nonlinear electrodynamics was developed. Using the experimental uncertainty in the ground state energy of the hydrogen atom, the bound b > 5.37 x 10{sup 20}K(V)/(m), where K = 2, 4√(2)/3 and √(π) for the Born-Infeld, Logarithmic and Exponential electrodynamics respectively, was established. In the particular case of Born-Infeld electrodynamics, the constraint found for b was compared with other constraints present in the literature. (orig.)

  17. International Conference Approximation Theory XV

    CERN Document Server

    Schumaker, Larry

    2017-01-01

    These proceedings are based on papers presented at the international conference Approximation Theory XV, which was held May 22–25, 2016 in San Antonio, Texas. The conference was the fifteenth in a series of meetings in Approximation Theory held at various locations in the United States, and was attended by 146 participants. The book contains longer survey papers by some of the invited speakers covering topics such as compressive sensing, isogeometric analysis, and scaling limits of polynomials and entire functions of exponential type. The book also includes papers on a variety of current topics in Approximation Theory drawn from areas such as advances in kernel approximation with applications, approximation theory and algebraic geometry, multivariate splines for applications, practical function approximation, approximation of PDEs, wavelets and framelets with applications, approximation theory in signal processing, compressive sensing, rational interpolation, spline approximation in isogeometric analysis, a...

  18. International Network for Capacity Building for the Control of Emerging Viral Vector-Borne Zoonotic Diseases: Arbo-Zoonet

    NARCIS (Netherlands)

    Ahmed, J.; Bouloy, M.; Ergonul, O.; Fooks, A.R.; Paweska, J.; Chevalier, V.; Drosten, C.; Moormann, R.J.M.; Tordo, N.; Vatansever, Z.; Calistri, P.; Estrada-Pena, A.; Mirazimi, A.; Unger, H.; Yin, H.; Seitzer, U.

    2009-01-01

    Arboviruses are arthropod-borne viruses, which include West Nile fever virus (WNFV), a mosquito-borne virus, Rift Valley fever virus (RVFV), a mosquito-borne virus, and Crimean-Congo haemorrhagic fever virus (CCHFV), a tick-borne virus. These arthropod-borne viruses can cause disease in different

  19. Geometrical dynamics of Born-Infeld objects

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, Ruben [Departamento de Fisica, Escuela Superior de Fisica y Matematicas del I.P.N., Unidad Adolfo Lopez Mateos, Edificio 9, 07738 Mexico, D.F. (Mexico); Molgado, Alberto [Facultad de Ciencias, Universidad de Colima, Bernal DIaz del Castillo 340, Col. Villas San Sebastian, Colima (Mexico); Rojas, Efrain [Facultad de Fisica e Inteligencia Artificial, Universidad Veracruzana, 91000 Xalapa, Veracruz (Mexico)

    2007-03-21

    We present a geometrically inspired study of the dynamics of Dp-branes. We focus on the usual non-polynomial Dirac-Born-Infeld action for the worldvolume swept out by the brane in its evolution in general background spacetimes. We emphasize the form of the resulting equations of motion which are quite simple and resemble Newton's second law, complemented with a conservation law for a worldvolume bicurrent. We take a closer look at the classical Hamiltonian analysis which is supported by the ADM framework of general relativity. The constraints and their algebra are identified as well as the geometrical role they play in phase space. In order to illustrate our results, we review the dynamics of a D1-brane immersed in a AdS{sub 3} x S{sup 3} background spacetime. We exhibit the mechanical properties of Born-Infeld objects paving the way to a consistent quantum formulation.

  20. Geometrical dynamics of Born-Infeld objects

    International Nuclear Information System (INIS)

    Cordero, Ruben; Molgado, Alberto; Rojas, Efrain

    2007-01-01

    We present a geometrically inspired study of the dynamics of Dp-branes. We focus on the usual non-polynomial Dirac-Born-Infeld action for the worldvolume swept out by the brane in its evolution in general background spacetimes. We emphasize the form of the resulting equations of motion which are quite simple and resemble Newton's second law, complemented with a conservation law for a worldvolume bicurrent. We take a closer look at the classical Hamiltonian analysis which is supported by the ADM framework of general relativity. The constraints and their algebra are identified as well as the geometrical role they play in phase space. In order to illustrate our results, we review the dynamics of a D1-brane immersed in a AdS 3 x S 3 background spacetime. We exhibit the mechanical properties of Born-Infeld objects paving the way to a consistent quantum formulation