11,906 research outputs found

    Transmission of Staphylococcus aureus from humans to green monkeys in the Gambia as revealed by whole-genome sequencing

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    En el marco de la actual crisis económica internacional y las consecuentes políticas de ajuste estructural adoptadas por el gobierno de España desde 2008, la investigación desarrollada centró su atención en los impactos diferenciados sobre un grupo de mujeres migrantes de origen colombiano residentes en el Sur de España, teniendo en cuenta que, ni el origen, ni las políticas de ajuste estructural implementadas, ni los efectos que está generando la denominada crisis económica, tienen un carácter neutral en cuanto al género, la clase social, la edad y la condición de extranjería. En este sentido, la investigación indagó a través de un grupo de mujeres cómo desde diversas trayectorias familiares, socioeconómicas y condición de extranjería, sus hogares están vivenciando la actual crisis económica en relación con lo laboral y lo familiar, así como también la incidencia en sus más estrechos vínculos transnacionales, todo ello dentro del actual proceso de reacomodamiento de la economía global

    Evaluation of a theory for pressure-strain rate

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    A theoretical expression for the slow part (the nonlinear fluctuation part) of the pressure-strain rate is compared with simulations of anisotropic homogeneous flows. The objective is to determine the quantitative accuracy of the theory and to test its prediction that the generalized Rotta coefficient, a non-dimensionalized ratio of slow term to the Reynolds stress anisotropy, varies with direction and can be negative. Comparisons are made between theoretical and simulation values of the slow term itself and of the generalized Rotta coefficients. The implications of the comparison for two-point closure theories and for Reynolds stress modeling are pointed out

    Optimization of design parameters for spacecraft nickel-cadmium cells containing recombination and control electrodes Quarterly report

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    Cycle capability of electrochemical cells built with oxygen recombination and oxygen sensing control electrode

    An evaluation of thematic mapper simulator data for the geobotanical discrimination of rock types in Southwest Oregon

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    Rock type identification may be assisted by the use of remote sensing of associated vegetation, particularly in areas of dense vegetative cover where surface materials are not imaged directly by the sensor. The geobotanical discrimination of ultramafic parent materials was investigated and analytical techniques for lithologic mapping and mineral exploration were developed. The utility of remotely sensed data to discriminate vegetation types associated with ultramafic parent materials in a study area in southwest Oregon were evaluated. A number of specific objectives were identified, which include: (1) establishment of the association between vegetation and rock types; (2) examination of the spectral separability of vegetation types associated with rock types; (3) determination of the contribution of each TMS band for discriminating vegetation associated with rock types and (4) comparison of analytical techniques for spectrally classifying vegetation

    Kinetic approach to electroweak baryogenesis

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    After a short review of baryogenesis mechanisms, we focus on the charge transport mechanism at the electroweak scale, effective at strong electroweak phase transitions. Starting from the one-loop Schwinger-Dyson equations for fermions coupled to bosons, we present a derivation of the relevant kinetic equations in the on-shell and gradient approximations, relevant for the thick wall baryogenesis regime. We then discuss the CP-violating source from the semiclassical force in the flow term, and compare it with the source arising in the collision term of the kinetic equation. Finally, we summarize the results concerning the chargino mediated baryogenesis in the Minimal Supersymmetric Standard Model.Comment: 13 pages, 6 figures. Invited talk at the International Workshop "Strong and Electroweak Matter 2002", October 2-5, 2002 Heidelberg, German

    Quantum Boltzmann equations for electroweak baryogenesis including gauge fields

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    We review and extend to include the gauge fields our derivation of the semiclassical limit of the collisionless quantum transport equations for the fermions in presence of a CP-violating bubble wall at a first order electroweak phase transition. We show how the (gradient correction modified) Lorenz-force appears both in the Schwinger-Keldysh approach and in the semiclassical WKB-treatment. In the latter approach the inclusion of gauge fields removes the apparent phase reparametrization dependence of the intermediate calculations. We also discuss setting up the fluid equations for practical calculations in electroweak baryogenesis including the self-consistent (hyper)electric field and the anomaly.Comment: 15 pages, talk presented by Kimmo Kainulainen at COSMO-01, Rovaniemi, Finland, 09/200

    Some aspects of collisional sources for electroweak baryogenesis

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    We consider the dynamics of fermions with a spatially varying mass which couple to bosons through a Yukawa interaction term and perform a consistent weak coupling truncation of the relevant kinetic equations. We then use a gradient expansion and derive the CP-violating source in the collision term for fermions which appears at first order in gradients. The collisional sources together with the semiclassical force constitute the CP-violating sources relevant for baryogenesis at the electroweak scale. We discuss also the absence of sources at first order in gradients in the scalar equation, and the limitations of the relaxation time approximation.Comment: 12 pages, 4 figures, talk presented by Tomislav Prokopec at COSMO-01, Rovaniemi, Finland, 09/2001 references added, minor changes in sections 5.3 and

    Inelastic diffractive scattering in nonperturbative QCD

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    We examine diffractive proton-proton scattering p p -> p X and photo- and electroproduction of \rho^0 mesons \gamma^(*) p -> \rho^0 X, where X denotes a proton or a final state, into which the proton can go by diffractive dissociation. Using a functional integral approach we derive the scattering amplitudes, which are governed by the expectation values of light-like Wegner-Wilson loops, which are then evaluated using the model of the stochastic vacuum. For the proton, we assume a quark-diquark structure. From the scattering amplitudes we calculate total and differential cross sections for high centre of mass energy and small momentum transfer and compare with experiments. Furthermore we calculate isovector form factors for the proton and the pion within the same model.Comment: 32 pages, 11 figures, v3: revised chapter 5, added appendix B, to be published in Eur.Phys.J.
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