209 research outputs found

    Aspectes citològics de la reproducció humana

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    On the theory of diamagnetism in granular superconductors

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    We study a highly disordered network of superconducting granules linked by weak Josephson junctions in magnetic field and develop a mean field theory for this problem. The diamagnetic response to a slow {\it variations} of magnetic field is found to be analogous to the response of a type-II superconductor with extremely strong pinning. We calculate an effective penetration depth λg\lambda_g and critical current jcj_c and find that both λg1\lambda_g^{-1} and jcj_c are non-zero but are strongly suppressed by frustration.Comment: REVTEX, 12 pages, two Postscript figure

    Medicaments: quin, quan, com...Projecte d’Aprenentatge i Servei per a secundària. Guia didàctica

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    Il·lustracions originals de Roser Bosch Mestres.La unitat didàctica que hem realitzat té com objectiu principal dissenyar un projecte d’Aprenentatge i Servei (APS) centrat en el bon ús dels medicaments. El projecte es caracteritza per ser una proposta educativa adreçada a joves d’ESO o de 1r curs de Batxillerat que combina activitats d’aprenentatge amb activitats de servei a la comunitat. Pensem que és un enfocament metodològic que ajuda a desenvolupar i a assolir determinades competències bàsiques, a la vegada que motiva l’alumnat, ja que es presenta un ensenyament contextualitzat i significatiu per a la comunitat. Els projectes d’APS responen a una necessitat concreta i rellevant de l’entorn social i, sempre que es pugui, ha d’implicar un acord de col·laboració entre diferents agents o institucions socials que possibilitin aquesta reciprocitat de beneficis d’aprenentatge i de servei. En aquest cas hem treballat com “partners” amb el Col·legi de farmacèutics, amb les farmàcies del barri i amb el SIGRE (responsable del reciclatge dels medicaments)

    On the Out of Equilibrium Relaxation of the Sherrington - Kirkpatrick model

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    We derive analytical results for the large-time relaxation of the Sherrington - Kirkpatrick model in the thermodynamic limit, starting from a random configuration. The system never achieves local equilibrium in any fixed sector of phase-space, but remains in an asymptotic out of equilibrium regime. We propose as a tool, both numerical and analytical, for the study of the out of equilibrium dynamics of spin-glass models the use of `triangle relations' which describe the geometry of the configurations at three (long) different times.Comment: 42 Pages + 3 Figures upon reques

    Phase space geometry and slow dynamics

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    We describe a non-Arrhenius mechanism for slowing down of dynamics that is inherent to the high dimensionality of the phase space. We show that such a mechanism is at work both in a family of mean-field spin-glass models without any domain structure and in the case of ferromagnetic domain growth. The marginality of spin-glass dynamics, as well as the existence of a `quasi equilibrium regime' can be understood within this scenario. We discuss the question of ergodicity in an out-of equilibrium situation.Comment: 23 pages, ReVTeX3.0, 6 uuencoded postscript figures appende

    Medicamentos: cuál, cuándo, cómo. Proyecto de Aprendizaje y Servicio para secundaria. Guía didáctica.

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    La unidad didáctica que hemos realizado tiene como objetivo principal diseñar un proyecto de Aprendizaje y Servicio (APS) centrado en el uso adecuado de los medicamentos. El proyecto se caracteriza por ser una propuesta educativa dirigida a jóvenes de ESO o de primer curso de Bachillerato que combina actividades de aprendizaje con actividades de servicio a la comunidad. El enfoque metodológico de esta unidad didáctica ayudará a desarrollar y alcanzar determinadas competencias básicas, al tiempo que motivará al alumnado, ya que se presenta una enseñanza contextualizada y significativa para la comunidad. Los proyectos de APS responden a una necesidad concreta y relevante del entorno social y, siempre que se pueda, deben implicar un acuerdo de colaboración entre distintos agentes o instituciones sociales que posibiliten esta reciprocidad de beneficios de aprendizaje y servicio. En este caso, hemos trabajado como partners con el Colegio de Farmacéuticos de Barcelona, las farmacias de barrio y SIGRE Medicamento y Medio Ambiente (entidad sin ánimo de lucro responsable del reciclado de los envases y restos de medicamentos de origen domiciliario). Hemos decidido centrarnos en el ámbito del «uso de los medicamentos», un ámbito de actuación que favorece en especial el aprendizaje y la aplicación de conocimientos del currículo de ciencias, puesto que estamos convencidos de la importancia de que la escuela forme a los jóvenes para ser competentes (lúcidos, eficientes y responsables) en dicho aspecto, de gran transcendencia para la salud, en la esfera personal, familiar y social, así como para el medio ambiente. El objetivo principal del proyecto es tomar consciencia de la importancia de utilizar correctamente los medicamentos, tanto desde el punto de vista de la salud como del medio ambiente. Para lograrlo se han diseñado actividades de enseñanza/aprendizaje de tipo «experiencial», en el sentido de que los alumnos se impliquen y puedan adquirir y aplicar conocimientos en distintos contextos. Hemos diseñado distintas actividades: estudio de casos, trabajo cooperativo, análisis de etiquetas de medicamentos, reciclado de los medicamentos en el domicilio y en la escuela, organización del contenido adecuado de un botiquín doméstico, entre otras. En cuanto a lo referente al servicio, se propone la revisión del botiquín de casa y de la escuela, así como acudir al punto SIGRE de la farmacia a llevar los medicamentos que ya no se utilicen o estén caducados, tanto si están vacíos como no. Además, se sugieren otras actividades, como una campaña de sensibilización para los compañeros y demás escuelas de niveles inferiores, en la que se haga referencia a cuáles son los medicamentos básicos necesarios en un botiquín, pero también se argumente la necesidad de realizar una recogida especial de los mismos, relacionándolo con el medio ambiente Este proyecto se puede aplicar tanto a 3º de ESO por el tema de Salud y enfermedades, como a 1º de Bachillerato, dentro de la materia Ciencias para el Mundo Contemporáneo

    Morfologia i formació del complexe sinaptinèmic a espermatòcits i oòcits de Mus musculus

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    A method for the sequential study of synaptonemal complexes by light and electron microscopy has been used to characterize the synaptic process in mouse (Mus musculus) spermatocytes and oocytes. Pre- and post-synaptic figures can be easily identified

    Ventricular arrhythmias in patients with functional mitral regurgitation and implantable cardiac devices: implications of mitral valve repair with Mitraclip

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    Background: Limited information has been reported regarding the impact of percutaneous mitral valve repair (PMVR) on ventricular arrhythmic (VA) burden. The aim of this study was to address the incidence of VA and appropriate antitachycardia implantable cardiac defibrillator (ICD) therapies before and after PMVR. Methods: We retrospectively analyzed all consecutive patients with heart failure with reduce left ventricular ejection fraction (LVEF), functional mitral regurgitation (FMR) grade 3+ or 4+ and an active ICD or cardiac resynchronizer who underwent PMVR in any of the eleven recruiting centers. Only patients with complete available device VA monitoring from one-year before to one year after PMVR were included. Baseline clinical and echocardiographic characteristics were collected before PMVR and at 12-months follow-up. Results: Ninety-three patients (68.2+/-10.9 years old, male 88.2%) were enrolled. PMVR was successfully performed in all patients and device success at discharge was 91.4%. At 12-month follow-up, we observed a significant reduction in mitral regurgitation severity, NT-proBNP and prevalence of severe pulmonary hypertension and severe kidney disease. Patients also referred a significant improvement in NYHA functional class and showed a non-significant trend to reserve left ventricular remodeling. After PMVR a significant decrease in the incidence of non-sustained ventricular tachycardia (VT) (5.0+/-17.8 vs. 2.7+/-13.5, P=0.002), sustained VT or ventricular fibrillation (0.9+/-2.5 vs. 0.5+/-2.9, P=0.012) and ICD antitachycardia therapies (2.5+/-12.0 vs. 0.9+/-5.0, P=0.033) were observed. Conclusions: PMVR was related to a reduction in arrhythmic burden and ICD therapies in our cohort

    Sensitivity of a tonne-scale NEXT detector for neutrinoless double beta decay searches

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    The Neutrino Experiment with a Xenon TPC (NEXT) searches for the neutrinoless double-beta decay of Xe-136 using high-pressure xenon gas TPCs with electroluminescent amplification. A scaled-up version of this technology with about 1 tonne of enriched xenon could reach in less than 5 years of operation a sensitivity to the half-life of neutrinoless double-beta decay decay better than 1E27 years, improving the current limits by at least one order of magnitude. This prediction is based on a well-understood background model dominated by radiogenic sources. The detector concept presented here represents a first step on a compelling path towards sensitivity to the parameter space defined by the inverted ordering of neutrino masses, and beyond.Comment: 22 pages, 11 figure

    Percutaneous mitral valve repair : Outcome improvement with operator experience and a second-generation device

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    Background and aim: Recent randomized data comparing percutaneous mitral valve repair (PMVR) versus optimal medical treatment in patients with functional MR (FMR) seemed to highlight the importance of the learning curve not only for procedural outcomes but also for patient selection. The aim of the study was to compare a contemporary series of patients undergoing PMVR using a second-generation Mitraclip device (Mitraclip NT) with previous cohorts treated with a first-generation system. Methods: This multicenter study collected individual data from 18 centers between 2012 and 2017. The cohort was divided into three groups according to the use of the first-generation Mitraclip during the first (control-1) or second half (control-2) or the Mitraclip NT sys-tem. Results: A total of 545 consecutive patients were included in the study. Among all, 182 (33.3%), 183 (33.3%), and 180 (33.3%) patients underwent mitral repair in the control-1, control-2, and NT cohorts, respectively. Procedural success was achieved in 93.3% of patients without differences between groups. Major adverse events did not statistically differ among groups, but there was a higher rate of pericardial effusion in the control-1 group (4.3%, 0.6%, and 2.6%, respectively; p = 0.025). The composite endpoint of death, surgery, and admission for congestive heart failure (CHF) at 12 months was lower in the NT group (23.5% in control-1, 22.5% in control-2, and 8.3% in the NT group; p = 0.032). Conclusions: The present paper shows that contemporary clinical outcomes of patients undergoing PMVR with the Mitraclip system have improved over time
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