1,308 research outputs found

    PCR-based Landmark Unique Gene (PLUG) markers are a useful tool for comparative genomic analysis and BAC clone screening in wheat

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    Dissertação de mestrado em Psicologia Clínica e Saúde (Psicopatologia e Psicoterapia Dinâmica), apresentada à Faculdade de Psicologia e Ciências da Educação da Universidade de CoimbraOs pacientes infetados pelo VIH têm sido objeto de interesse por parte dos profissionais de saúde mental pela dimensão do impacto psicológico do diagnóstico, evolução da infeção e a vulnerabilidade destes sujeitos. Seja como for, em traço de evolução da terapêutica, a infeção pelo vírus da imunodeficiência humana (VIH) é, atualmente, uma doença tendencialmente crónica. Entre as perturbações mentais, a depressão é descrita como uma das comorbidades mais frequentes nos indivíduos com VIH e que muitas vezes passa despercebida. Acompanha-se de elevada morbilidade e apresenta um impacto sócio-económico, sendo uma das causas mais frequentes de suicídio. Para além da incapacidade que se vai instalando progressivamente, os indivíduos são confrontados com o estigma social, carência de apoio social e isolamento. Neste sentido, este estudo foi realizado com o intuito de chamar a atenção para a necessidade de intervenção psicoterapêutica com esta população, através da exploração dos sintomas psicopatológicos mais prevalentes (com especial destaque para a depressão e para a ideação suicida), tendo em consideração a progressão da doença e a as caraterísticas socio-demográficas.Patients infected with HIV have been the object of interest on the part of mental health professionals due to the dimension of the psychological impact of the diagnosis, the course of infection and the vulnerability of these subjects. Anyway, in trait evolution of therapy, infection by the human immunodeficiency virus (HIV) is currently a chronic disease. Among mental disorders, depression is described as one of the most frequent comorbidities in individuals infected with HIV and which often goes unnoticed. It is accompanied by high morbidity and presents a socialeconomic impact, being one of the most frequent causes of suicide. Beyond the progressively established disability, individuals face social stigma, lack of social support and isolation. Thus, this study was conducted in order to draw attention to the need for psychotherapeutic intervention among this population, through the exploitation of the most prevalent psychopathological symptoms (with special emphasis on depression and suicidal ideation), taking into account the progression of this disease and the social-demographic characteristics

    Two tricritical lines from a Ginzburg-Landau expansion: application to the LOFF phase

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    We study the behavior of the two plane waves configuration in the LOFF phase close to T=0. The study is performed by using a Landau-Ginzburg expansion up to the eighth order in the gap. The general study of the corresponding grand potential shows, under the assumption that the eighth term in the expansion is strictly positive, the existence of two tricritical lines. This allows to understand the existence of a second tricritical point for two antipodal plane waves in the LOFF phase and justifies why the transition becomes second order at zero temperature. The general analysis done in this paper can be applied to other cases.Comment: LaTex file, 15 pages, 6 figure

    Density of States and Energy Gap in Andreev Billiards

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    We present numerical results for the local density of states in semiclassical Andreev billiards. We show that the energy gap near the Fermi energy develops in a chaotic billiard. Using the same method no gap is found in similar square and circular billiards.Comment: 9 pages, 6 Postscript figure

    The Superconducting Proximity Effect as a Tool to Investigate Metal Films and Interfaces

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    052The superconducting proximity effect is measured in sandwiches of thin Pb films and the alkali metals Cs, Rb, K and Na. The TcT_{c}-dependence provides information about the interface barriers between Pb and the alkalis. Such a barrier is particularly large in Pb/Cs sandwiches. It is not due to impurities or oxydation. In the presence of a sufficiently strong barrier a special form of the Cooper limit can be applied to calculate the transition temperature of the sandwich

    Bogoliubov - de Gennes versus Quasiclassical Description of Josephson Structures

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    The applicability of the quasiclassical theory of superconductivity in Josephson multi-layer structures is analyzed. The quasiclassical approach is compared with the exact theory based on the Bogoliubov - de Gennes equation. The angle and energy resolved (coarse-grain) currents are calculated using both techniques. It is shown that the two approaches agree in SISISSIS'IS'' geometries after the coarse-grain averaging. A quantitative discrepancy, which exceeds the quasiclassical accuracy, is observed when three or more interfaces are present. The invalidity of the quasiclassical theory is attributed to the presence of closed trajectories formed by sequential reflections on the interfaces.Comment: revtex4,12 pages, 12 figure

    Energy and pressure densities of a hot quark-gluon plasma

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    We calculate the energy and hydrostatic pressure densities of a hot quark-gluon plasma in thermal equilibrium through diagrammatic analyses of the statistical average, Θμν\langle \Theta_{\mu \nu} \rangle, of the energy-momentum-tensor operator Θμν\Theta_{\mu \nu}. To leading order at high temperature, the energy density of the long wave length modes is consistently extracted by applying the hard-thermal-loop resummation scheme to the operator-inserted no-leg thermal amplitudes Θμν\langle \Theta_{\mu \nu} \rangle. We find that, for the long wave length gluons, the energy density, being positive, is tremendously enhanced as compared to the noninteracting case, while, for the quarks, no noticeable deviation from the noninteracting case is found.Comment: 33 pages. Figures are not include

    Ultrafast optical nonlinearity in quasi-one-dimensional Mott-insulator Sr2CuO3{\rm Sr_2CuO_3}

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    We report strong instantaneous photoinduced absorption (PA) in the quasi-one-dimensional Mott insulator Sr2CuO3{\rm Sr_2CuO_3} in the IR spectral region. The observed PA is to an even-parity two-photon state that occurs immediately above the absorption edge. Theoretical calculations based on a two-band extended Hubbard model explains the experimental features and indicates that the strong two-photon absorption is due to a very large dipole-coupling between nearly degenerate one- and two-photon states. Room temperature picosecond recovery of the optical transparency suggests the strong potential of Sr2CuO3{\rm Sr_2CuO_3} for all-optical switching.Comment: 10 pages, 4 figure

    Rough Surface Effect on Meissner Diamagnetism in Normal-layer of N-S Proximity-Contact System

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    Rough surface effect on the Meissner diamagnetic current in the normal layer of proximity contact N-S bi-layer is investigated in the clean limit. The diamagnetic current and the screening length are calculated by use of quasi-classical Green's function. We show that the surface roughness has a sizable effect, even when a normal layer width is large compared with the coherence length ξ=vF/πTc\xi =v_{\rm F}/\pi T_{\rm c}. The effect is as large as that of the impurity scattering and also as that of the finite reflection at the N-S interface.Comment: 12 pages, 3 figures. To be published in J. Phys. Soc. Jpn. Vol.71-

    Andreev Bound States and Self-Consistent Gap Functions for SNS and SNSNS Systems

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    Andreev bound states in clean, ballistic SNS and SNSNS junctions are calculated exactly and by using the Andreev approximation (AA). The AA appears to break down for junctions with transverse dimensions chosen such that the motion in the longitudinal direction is very slow. The doubly degenerate states typical for the traveling waves found in the AA are replaced by two standing waves in the exact treatment and the degeneracy is lifted. A multiple-scattering Green's function formalism is used, from which the states are found through the local density of states. The scattering by the interfaces in any layered system of ballistic normal metals and clean superconducting materials is taken into account exactly. The formalism allows, in addition, for a self-consistent determination of the gap function. In the numerical calculations the pairing coupling constant for aluminum is used. Various features of the proximity effect are shown
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