421 research outputs found

    Barriers to better care for people with AIDS in developing countries

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    Access to good quality antiretroviral treatment has transformed the prognosis for people with AIDS in the developed world. Although it is feasible and desirable to deliver antiretroviral drugs in resource poor settings,few of the 95% of people with HIV and AIDS who live in developing countries receive them. The World Health Organization has launched a programme to deliver antiretroviral drugs to three million people with AIDS in the developing world by 2005, the “3 by 5” initiative. We identify some of the challenges faced by the initiative, focusing on delivery of care

    Les femmes africaines face à l'épidémie de sida

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    En Afrique, les femmes sont plus nombreuses que les hommes à être infectées par le virus du sida. Plus vulnérables biologiquement, elles n’ont pas toujours la capacité de négocier qui leur permettrait d’insister sur l’utilisation de préservatifs ou sur la fidélité de leur partenaire. Prévention et dépistage, encore rares, leur sont cependant plus accessibles qu’aux hommes grâce aux consultations prénatales. Mais, si elles apprennent qu’elles sont infectées, leur fragilité socio-économique, la peur de l’opprobre et la pression de procréation qu’elles subissent, conduisent trois femmes sur quatre à taire leur séropositivité. Paradoxalement, elles bénéficient pourtant plus souvent que les hommes des traitements

    Relativistic calculations of pionic and kaonic atoms hyperfine structure

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    We present the relativistic calculation of the hyperfine structure in pionic and kaonic atoms. A perturbation method has been applied to the Klein-Gordon equation to take into account the relativistic corrections. The perturbation operator has been obtained \textit{via} a multipole expansion of the nuclear electromagnetic potential. The hyperfine structure of pionic and kaonic atoms provide an additional term in the quantum electrodynamics calculation of the energy transition of these systems. Such a correction is required for a recent measurement of the pion mass

    Dielectronic Resonance Method for Measuring Isotope Shifts

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    Longstanding problems in the comparison of very accurate hyperfine-shift measurements to theory were partly overcome by precise measurements on few-electron highly-charged ions. Still the agreement between theory and experiment is unsatisfactory. In this paper, we present a radically new way of precisely measuring hyperfine shifts, and demonstrate its effectiveness in the case of the hyperfine shift of 4s_1/24s\_{1/2} and 4p_1/24p\_{1/2} in 207Pb53+^{207}\mathrm{Pb}^{53+}. It is based on the precise detection of dielectronic resonances that occur in electron-ion recombination at very low energy. This allows us to determine the hyperfine constant to around 0.6 meV accuracy which is on the order of 10%

    Tensorial form and matrix elements of the relativistic nuclear recoil operator

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    Within the lowest-order relativistic approximation (v2/c2\sim v^2/c^2) and to first order in me/Mm_e/M, the tensorial form of the relativistic corrections of the nuclear recoil Hamiltonian is derived, opening interesting perspectives for calculating isotope shifts in the multiconfiguration Dirac-Hartree-Fock framework. Their calculation is illustrated for selected Li-, B- and C-like ions. The present work underlines the fact that the relativistic corrections to the nuclear recoil are definitively necessary for getting reliable isotope shift values.Comment: 22 pages, no figures, submitted to J. Phys.

    Coordinate-space approach to the bound-electron self-energy: Self-Energy screening calculation

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    The self-energy screening correction is evaluated in a model in which the effect of the screening electron is represented as a first-order perturbation of the self energy by an effective potential. The effective potential is the Coulomb potential of the spherically averaged charge density of the screening electron. We evaluate the energy shift due to a 1s1/21s_{1/2}, 2s1/22s_{1/2}, 2p1/22p_{1/2}, or 2p3/22p_{3/2} electron screening a 1s1/21s_{1/2}, 2s1/22s_{1/2}, 2p1/22p_{1/2}, or 2p3/22p_{3/2} electron, for nuclear charge Z in the range 5Z925 \le Z\le 92. A detailed comparison with other calculations is made.Comment: 54 pages, 10 figures, 4 table
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