789 research outputs found

    Improved strategies for variational calculations for helium

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    The aim of this work is to apply trial functions constructed from Hylleraas functions with three independent sets of nonlinear scale factors to variational calculations for helium and helium-like ions. The ground state and low-lying Rydberg energy levels of these ions have been calculated to several orders of magnitude greater accuracy than previous work in this area while using an equal, or in most cases, a reduced number of basis functions. Each of the three sectors of the basis set is found to describe a different scale of coordinate space corresponding to the asymptotic, intermediate, and close-ranged distances between particles. The incorporation of the third, close-ranged sector, allows the basis set to better model complex correlation effects between the nucleus and the two electrons in the atomic three-body problem. Optimization of the basis set parameters is achieved through standard variational techniques and the validity of the wave functions near the electron-nucleus and electron-electron coalescence points is tested using the Kato cusp conditions. The tripled basis set is also applied to the 1/ Z perturbation expansion as a case study. A multiple-precision package, MPFUN90 written by David H. Bailey, was used to alleviate numerical instabilities which arose for certain states.Dept. of Physics. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .N57. Source: Masters Abstracts International, Volume: 43-01, page: 0225. Adviser: G. W. F. Drake. Thesis (M.Sc.)--University of Windsor (Canada), 2004

    Training Prison Staff on Issues of Young Prisoners’ Health Needs

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    open access articleYoung prisoners’ health needs represent a matter of constant importance for any prison administration. These are addressed through direct medical services, as well as through other activities of health promotion. If the medical services are provided by trained medical staff, health promotion is usually provided by non-medical staff, such as social workers, psychologists, educators etc. Also, because healthy behaviors are best promoted through social modeling, such activities require the involvement of all prison staff, including non-specialists such as guardians. Thus, for health promotion to be effective it needs to be approached by the whole prison staff, meaning that the medical and non-medical specialists, as well as other prison staff need to have a common understanding of young prisoners health needs and to work as a team. This can be done through prison staff training. The article addresses these issues by summarizing the Romanian country reports of the project “Health Promotion for Young Prisoners” funded by the EU in the framework of the Public Health Program

    Fredholm conditions for invariant operators: finite abelian groups and boundary value problems

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    We answer the question of when an invariant pseudodifferential operator is Fredholm on a fixed, given isotypical component. More precisely, let Γ\Gamma be a compact group acting on a smooth, compact, manifold MM without boundary and let Pψm(M;E0,E1)P \in \psi^m(M; E_0, E_1) be a Γ\Gamma-invariant, classical, pseudodifferential operator acting between sections of two Γ\Gamma-equivariant vector bundles E0E_0 and E1E_1. Let α\alpha be an irreducible representation of the group Γ\Gamma. Then PP induces by restriction a map πα(P):Hs(M;E0)αHsm(M;E1)α\pi_\alpha(P) : H^s(M; E_0)_\alpha \to H^{s-m}(M; E_1)_\alpha between the α\alpha-isotypical components of the corresponding Sobolev spaces of sections. We study in this paper conditions on the map πα(P)\pi_\alpha(P) to be Fredholm. It turns out that the discrete and non-discrete cases are quite different. Additionally, the discrete abelian case, which provides some of the most interesting applications, presents some special features and is much easier than the general case. We thus concentrate in this paper on the case when Γ\Gamma is finite abelian. We prove then that the restriction πα(P)\pi_\alpha(P) is Fredholm if, and only if, PP is "α\alpha-elliptic", a condition defined in terms of the principal symbol of PP. If PP is elliptic, then PP is also α\alpha-elliptic, but the converse is not true in general. However, if Γ\Gamma acts freely on a dense open subset of MM, then PP is α\alpha-elliptic for the given fixed α\alpha if, and only if, it is elliptic. The proofs are based on the study of the structure of the algebra ψm(M;E)Γ\psi^{m}(M; E)^\Gamma of classical, Γ\Gamma-invariant pseudodifferential operators acting on sections of the vector bundle EME \to M and of the structure of its restrictions to the isotypical components of Γ\Gamma. These structures are described in terms of the isotropy groups of the action of the group Γ\Gamma on EME \to M

    Growing Season Climate Variability and its Influence on Sauvignon Blanc and Pinot Gris Berries and Wine Quality: Study Case in Romania (2005-2015)

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    The purpose of our research was to find out what influence climatic variability in the growing season has on the berry and wine composition in two white grape varieties grown in the vineyard of Banat Universityof Agricultural Sciences and Veterinary Medicine from Timisoara, located in the western area of Romania.  The quality and characteristics of the wines produced in a limited area is essentially due to the environment,including natural and human factors. Two white cool-intermediate climate grape varieties - Sauvignon Blanc and Pinot Gris were chosen to study the impact of climate change on the main characteristics of juice and wine. A number of 40 berries from each variety was chosen for phenol extraction, total soluble solids (sugar content), titratable acidity and pH determinations. Wine samples were analysed after one year of ageing in the bottle. Alcohol concentration was not majorly influenced by temperature and rainfall over the years. Some experimental years with hot weather were favourable for sugar accumulation in berries and wine respectively;therefore, potential alcohol also increased. In the last decade, annual and monthly variability of rainfall and temperature influenced the phenological cycle of grapevines most, delaying or accelerating the developing of foliar area, as well as the ripening and harvesting time, which has a direct influence on grapes and wine products

    Ground-state energies for helium, H-, and Ps-

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    Nonrelativistic energy and other properties of He, H- and Ps- were discussed using a triple basis set in Hylleraas coordinates. The stability and efficiency of the computational method was compared with the quasirandom method. Results showed that the triple basis set in Hylleraas coordinates is capable of exceeding the accuracy of calculations for three-body system based on quasirandom Monte Carlo methods
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