1,230 research outputs found

    Biphasic effect of insulin on beta cell apoptosis depending on glucose deprivation

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    AbstractInsulin resistant states are associated with an increase in the beta cell mass and also high levels of circulating insulin. Ultimately the beta cells undergo a failure that leads to diabetes. At this stage, a question arises if those persistent high levels of circulating insulin may contribute to beta cell damage. To address this important issue, we submitted beta cells to a prolonged effect of increasing concentrations of insulin. We observed that a prolonged effect of high levels of insulin on the presence of serum (15–24h) in glucose-deprived beta cells induced apoptosis. This apoptotic effect was both dose- and cycloheximide-dependent

    Analysis of thermal resistance evolution of ash deposits during co-firing of coal with biomass and coal mine waste residues

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    Co-firing biomass or waste fuels with coal in conventional thermal plants is a promising way to reduce environmental impact of human activities with an acceptable economic investment. One of the main issues to be addressed is the worsening in ash fouling and the reduction of heat transfer rate. In the present paper, the deposits thermal resistance during direct combustion of different blends of coal and various native fuels is investigated by using a deposition probe, kept at 550 °C in order to emulate the conditions of superheaters of conventional power units. Two energy crops (Cynara cardunculus L. and Populus spp.), a forest residue (Pinus pinaster) and a waste coal (coal mine waste residues) were successfully tested in a semi-industrial scale pilot plant. A thermal model of the probe is presented to estimate heat transfer rate and thermal resistance of ash deposits. After the validation with experimental data, a sensitivity analysis allows to identify the deposit surface emissivity and the flue gas temperature as the most influential parameters. The heat uptake in air flow decreases with time for all the experimental tests in spite of the increase in flue gas and walls temperatures. Except for poplar blends, under similar operation conditions, a rise in the substitution percentage means faster decreasing rates in heat transfer and higher thermal resistance due to the ash deposits, especially for cynara and coal mine waste residues. The present work demonstrates the usefulness of thermal models to estimate the thermal resistance of ash deposits without the need of sophisticated instrumentation. Dedicated thermal models, similar to the developed one, could serve to design smart cleaning sequences to improve efficiency in power generation processes

    El sueño del cautivo

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    Dibujo de Miguel C. Clementson Lop

    Comparativa

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    Dibujo de Miguel C. Clementson Lop

    Geogonía

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    Dibujo de Miguel C. Clementson Lop

    Homilía de los sueños

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    Dibujo de Miguel C. Clementson Lop

    European Economies in the First Epoch of Imperialism and Mercantilism. 1415-1846.

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    The costs and benefits of European Imperialism from the conquest of Ceuta, 1415, to the Treaty of Lusaka, 1974.Twelfth International Economic History Congress. Madrid, 1998.Patrick K. O'Brien and Leandro Prados de la Escosura (eds.)Editada en la Fundación Empresa PúblicaJorge M. Pedreira. «To Have and To Have not». The Economic Consequences of Empire: Portugal (1415-1822).-- Bartolomé Yun-Casalilla. The American Empire and the Spanish Economy: An Institutional and Regional Perspective.-- Pieter C. Emmer. The Economic Impact of the Dutch Expansion Overseas, 1570-1870.-- Paul Butel and François Crouzet. Empire and Economic Growth: the Case of 18th Century France.-- Stanley L. Engerman. British Imperialism in a Mercantilist Age, 1492-1849: Conceptual Issues and Empirical Problems.Publicad

    Perpendicular magnetic anisotropy and intralayer interactions in a single layer of CoPt nanoparticles

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    The multilayer films Al2O3/tCo Co/tPt Pt]N, produced by sequential deposition of Co and Pt on alumina consist in layers of CoPt alloyed nanoparticles. They show perpendicular magnetic anisotropy (PMA) below a freezing temperature Tf, an asperomagnetic-like phase below that temperature, and hard ferromagnetic ordering below a transition temperature T1 < Tf. A single layer granular film (N = 1) with deposition thicknesses tCo=0.7 nm, tPt=1.5 nm and particle diameter of 3 nm is presently studied. SQUID magnetometry shows that a single layer presents the three phases as well. Para-, aspero-and ferromagnetic phases are observed upon lowering the temperature, with transition temperatures Tf ˜ 375 K and T1 ˜ 200 K, respectively. In addition, the PMA persists, proving that there is no interlayer coupling in the multilayer system. SQUID results also reveal a core-shell structure in the CoPt nanoparticles

    Effectiveness of a Surgery Admission Unit for patients undergoing major elective surgery in a tertiary university hospital

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    <p>Abstract</p> <p>Background</p> <p>The increasing demand on hospitalisation, either due to elective activity from the waiting lists or due to emergency admissions coming from the Emergency Department (ED), requires looking for strategies that lead to effective bed management. The aim of this study was to evaluate the effectiveness of a surgery admission unit for major elective surgery patients who were admitted for same-day surgery.</p> <p>Methods</p> <p>We included all patients admitted for elective surgery in a university tertiary hospital between the 1st of September and the 31st of December 2006, as well as those admitted during the same period of 2008, after the introduction of the Surgery Admission Unit. The main outcome parameters were global length of stay, pre-surgery length of stay, proportion of patients admitted the same day of the surgery and number of cancellations. Differences between the two periods were evaluated by the T-test and Chi-square test. Significance at P < 0.05 was assumed throughout.</p> <p>Results</p> <p>We included 6,053 patients, 3,003 during 2006 and 3,050 patients during 2008. Global length of stay was 6.2 days (IC 95%:6.4-6) in 2006 and 5.5 days (IC 95%:5.8-5.2) in 2008 (p < 0.005). Pre-surgery length of stay was reduced from 0.46 days (IC 95%:0.44-0.48) in 2006 to 0.29 days (IC 95%:0.27-0.31) in 2008 (p < 0.005). The proportion of patients admitted for same-day surgery was 67% (IC 95%:69%-65%) in 2006 and 76% (IC 95%:78%-74%) in 2008 (p < 0.005). The number of cancelled interventions due to insufficient preparation was 31 patients in 2006 and 7 patients in 2008.</p> <p>Conclusions</p> <p>The implementation of a Surgery Admission Unit for patients undergoing major elective surgery has proved to be an effective strategy for improving bed management. It has enabled an improvement in the proportion of patients admitted on the same day as surgery and a shorter length of stay.</p

    Innovación docente mediante la creación de recursos visuales para el aprendizaje de las ciencias geológicas

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    En el contexto de los proyectos “Redes de investigación en docencia universitaria de la Universidad de Alicante”, se ha creado la red Banco de imágenes de minerales y rocas. El objetivo es elaborar un banco de imágenes empleando los materiales de las colecciones docentes de mineralogía y petrología, para usarlo como herramienta docente en todos los Grados que imparten alguna asignatura de Geología, así como en los cursos del Grado en Geología. En esta fase de la red, se establecen las pautas para la elaboración del material, utilizando los más altos criterios de calidad en las imágenes obtenidas. Se determina cuál es el instrumental más adecuado para la obtención de las imágenes, el cual depende de las condiciones de la muestra cuya imagen se pretende obtener. Además cada muestra presenta diferentes requisitos de iluminación, que son establecidos tras la realización de numerosos ensayos. Para la obtención de pequeños detalles, se hace uso de instrumental específico (microscopios compuestos y de polarización o lupas) que requiere de adaptadores especiales para poder obtener las imágenes. Una vez creado el banco de imágenes se elaborarán recursos didácticos específicos, como guiones de prácticas, manuales, páginas web y otros recursos que permitan el autoaprendizaje del alumno
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