6,148 research outputs found

    Cuba, Estados Unidos y España en el descubrimiento de la fiebre amarilla

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    El Dr. Turró

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    Efficiency of public and publicly-subsidised high schools in Spain. Evidence from PISA 2006

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    The purpose of this paper is to compare the efficiency of the Spanish public and publicly-subsidised private high schools using Data Envelopment Analysis (DEA) fed by the results provided by a hierarchical linear model (HLM) applied to PISA-2006 (Programme for International Students Assessment) microdata. This study places special emphasis on the estimation of the determinants of school outcomes, the educational production function being estimated through an HLM that takes into account the nested nature of PISA data. Inefficiencies are then measured through the DEA and decomposed into managerial (related to individual performance) and programme (related to structural differences between management models), following Silva Portela and Thanassoulis (2001) approach. Once differences in pupils’ background and individual management inefficiencies have been eliminated, results reveal that Spanish public high schools are more efficient than publicly-subsidised private ones

    Complex noise in diffusion-limited reactions of replicating and competing species

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    We derive exact Langevin-type equations governing quasispecies dynamics. The inherent multiplicative noise has both real and imaginary parts. The numerical simulation of the underlying complex stochastic partial differential equations is carried out employing the Cholesky decomposition for the noise covariance matrix. This noise produces unavoidable spatio-temporal density fluctuations about the mean field value. In two dimensions, the fluctuations are suppressed only when the diffusion time scale is much smaller than the amplification time scale for the master species.Comment: 10 pages, 2 composite figure

    Progress report on the ultra heavy cosmic ray experiment (AO178)

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    The Ultra Heavy Cosmic Ray Experiment (UHCRE) is based on a modular array of 192 side-viewing solid state nuclear track detector stacks. These stacks were mounted in sets of four in 48 pressure vessels employing sixteen peripheral Long Duration Exposure Facility (LDEF) trays. The extended duration of the LDEF mission has resulted in a greatly enhanced scientific yield from the UHCRE. The geometry factor for high energy cosmic ray nuclei, allowing for Earth shadowing, was 30 sq m-sr, giving a total exposure factor of 170 sq m-sr-y at an orbital inclination of 28.4 degrees. Scanning results indicate that about 3000 cosmic ray nuclei in the charge region with Z greater than 65 were collected. This sample is more than ten times the current world data in the field (taken to be the data set from the HEAO-3 mission plus that from the Ariel-6 mission) and is sufficient to provide the world's first statistically significant sample of actinide (Z greater than 88) cosmic rays. Results to date are presented including details of ultra-heavy cosmic ray nuclei, analysis of pre-flight and post-flight calibration events and details of track response in the context of detector temperature history. The integrated effect of all temperature and age related latent track variations cause a maximum charge shift of +/- 0.8 e for uranium and +/- 0.6 e for the platinum-lead group. The precision of charge assignment as a function of energy is derived and evidence for remarkably good charge resolution achieved in the UHCRE is considered. Astrophysical implications of the UHCRE charge spectrum are discussed

    The LDEF ultra heavy cosmic ray experiment

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    The LDEF Ultra Heavy Cosmic Ray Experiment (UHCRE) used 16 side viewing LDEF trays giving a total geometry factor for high energy cosmic rays of 30 sq m sr. The total exposure factor was 170 sq m sr y. The experiment is based on a modular array of 192 solid state nuclear track detector stacks, mounted in sets of four in 48 pressure vessels. The extended duration of the LDEF mission has resulted in a greatly enhanced potential scientific yield from the UHCRE. Initial scanning results indicate that at least 1800 cosmic ray nuclei with Z greater than 65 were collected, including the world's first statistically significant sample of actinides. Post flight work to date and the current status of the experiment are reviewed

    Circulating anti-galectin-1 antibodies are associated with the severity of ocular disease in autoimmune and infectious uveitis

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    Galectin (Gal)-1, an endogenous lectin found at sites of immune privilege, plays a critical role in the regulation of the immune response. Therapeutic administration of Gal-1 or its genetic delivery suppresses chronic inflammation in experimental models of autoimmunity. The purpose of this work was to investigate the occurrence of circulating anti-Gal-1 antibodies in patients with autoimmune and infectious uveitis as potential determinant factors of disease progression.Fil: Romero, Marta D.. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Fundación Ver; Argentina. Laboratorio Inmunopatología Investigación y Docencia LIIDO; ArgentinaFil: Muiño, Juan Carlos. Universidad Nacional de Córdoba; Argentina. Fundación Ver; ArgentinaFil: Bianco, German Ariel. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Ferrero, Mercedes. Laboratorio Inmunopatología Investigación y Docencia LIIDO; Argentina. Fundación Ver; ArgentinaFil: Juarez, Claudio P.. Fundación Ver; ArgentinaFil: Luna, José Domingo. Fundación Ver; ArgentinaFil: Rabinovich, Gabriel A.. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin
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