5,676 research outputs found

    Micro-Jet Test Facility for Aerospace Propulsion Engineering Education

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    This paper describes the methodology that has been developed and implemented at the School ofAeronautics (ETSIA) of the Universidad Politecnica de Madrid (UPM) to familiarize aerospaceengineering students with the operation of real complex jet engine systems. This methodology has atwo-pronged approach: students carry out preparatory work by using, first, a gas turbineperformance prediction numerical code; then they validate their assumptions and results on anexperimental test rig. When looking at the educational aspects, we have taken care that, apart frombeing sufficiently robust and flexible, the experimental set-up is similar to real jet engine rigs, so thestudents are not constrained to exploring a much too limited parametric space. Also, because afacility like this is usually subject to extensive and somewhat rugged use, we have focused on a lowcost design

    Riesgo de resultados negativos asociados a inhibidores de la bomba de protones: revisión de las prescripciones electrónicas en pacientes polimedicados

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    Introducción: El elevado consumo de inhibidores de la bomba de protones (IBP) puede incrementar la probabilidad de aparición de interacciones clínicamente relevantes. Pacientes mayores, polimedicados y pluripatológicos representan un grupo de alto riesgo. Se espera que la revisión sistemática de las prescripciones electrónicas (PE) permita detectar potenciales interacciones farmacológicas.Material y métodos: Estudio retrospectivo, transversal y observacional: revisión de las PE de IBP dispensadas entre enero y diciembre de 2015 en una farmacia comunitaria rural.Resultados: 1.186 PE, 164 pacientes (edad 65,7±17,2). Mayor número de pacientes en rango de edad 71-80 (n=52). Medicamentos por paciente: 11,0±5,6. PE IBP sin indicación aprobada: 27%.  Indicación mayoritaria: protección frente a gastrolesión (77%). 29 pacientes (30%) con riesgo de resultados negativos asociados a la medicación (RNM) por omeprazol, 15 de ellos sin indicación. Patologías concomitantes más prevalentes: hipertensión arterial (n=81), dislipemia (n=61) y diabetes (n=36). Principios activos implicados: acenocumarol, hierro, cianocobalamina, escitalopram, benzodiazepinas y clopidogrel.Discusión: El 80% de las PE de omeprazol corresponde a pacientes entre 61 y 90 años, la mayoría con comorbilidad y polifarmacia, y supera el tiempo de tratamiento recomendado. Relacionamos la cronificación y el aumento del riesgo de RNM con la ausencia de un seguimiento adecuado.Muchos fármacos corresponsables del riesgo tratan los problemas de salud (PS) más prevalentes de nuestra población: la probabilidad de interacción resulta independiente de la correcta indicación del IBP.Conclusiones: La revisión de las PE permite valorar el riesgo de RNM y evaluar la información básica relativa al riesgo de interacción.Se detectaron RNM de no necesidad y de inseguridad en proporciones comparables. Un número elevado de PE de omeprazol tienden a cronificarse. Las interacciones más relevantes  registradas ocurren a nivel metabólico

    Application-layer Performance Analysis of PRIME in Smart Metering Networks

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    This paper assesses the performance of actual PRIME v1.3.6 and PRIME v1.4 systems when used for Smart Metering applications. The analysis is performed at the application level using the DLMS/COSEM stack. Hence, it considers performance indicators that are of practical interest for distribution system operators, such as the availability and the average time needed to read the energy load profile of all the meters. To this end, two test networks with 112 smart meters have been deployed in the laboratory (to ensure the stability of the network). In one of them all the Service Nodes communicate directly with the Base Node, while there exist up to 5 switching levels in the other tested network. First, the PRIME v1.3.6 system is evaluated, stressing the significant performance gain that can be obtained by implementing some MAC layer strategies, which are compatible with the specification but not specifically defined on it. Then,the improvement offered by the PRIME v1.4 system is assessed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Lista de los peces de la provincia de Jujuy

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    Fil: Fernández, Luis A.. Fundación Miguel Lillo. Tucumán; ArgentinaFil: Nadalin, Diego Oscar. División Zoología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: López, Hugo Luis. División Zoología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin

    Teaching Style in Physical Education and Changes of Daily Physical Activity after One Academic Year in Adolescents: GEOS Study

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    Increased Moderate-Vigorous physical activity (MVPA) and reduced sedentary time (ST) are key factors for a healthy lifestyle during childhood and adolescence. Studies have suggested that schools may be effective resources to promote healthy habits (Sallis, McKenzie et al. 2012). Therefore, in PE, is important to assess how teachers use strategies and provide students tools to engage in PA with the purpose of reduce the risk of sedentary behavior and contribute to promotion MVPA habits for a healthy lifestyle (Lonsdale, C. et al., 2013). Many factors may be involved in the successful PE class to promote healthy out-school behaviors, as teaching styles (TS), learning styles, learning time, motivation and so on (Mosston, M. 1966). Regarding TS, there is a lack of knowledge about influence of the teaching style (TS) in the promotion of daily MVPA. It was our aim to observe the differences of total daily PA dimensions between two groups of adolescents who were taught during a whole academic year using reproducing (RK) or producing knowledge (PK) TSs.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Temperature-dependent dynamical nuclear polarization bistabilities in double quantum dots in the spin-blockade regime

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    The interplay of dynamical nuclear polarization (DNP) and leakage current through a double quantum dot in the spin-blockade regime is analyzed. A finite DNP is built up due to a competition between hyperfine (HF) spin-flip transitions and another inelastic escape mechanism from the triplets, which block transport. We focus on the temperature dependence of the DNP for zero energy-detuning (i.e. equal electrostatic energy of one electron in each dot and a singlet in the right dot). Our main result is the existence of a transition temperature, below which the DNP is bistable, so a hysteretic leakage current versus external magnetic field B appears. This is studied in two cases: (i) Close to the crossing of the three triplet energy levels near B=0, where spin-blockade is lifted due to the inhomogeneity of the effective magnetic field from the nuclei. (ii) At higher B-fields, where the two spin-polarized triplets simultaneously cross two different singlet energy levels. We develop simplified models leading to different transition temperatures T_TT and T_ST for the crossing of the triplet levels and the singlet-triplet level crossings, respectively. We find T_TT analytically to be given solely by the HF couplings, whereas T_ST depends on various parameters and T_ST>T_TT. The key idea behind the existence of the transition temperatures at zero energy-detuning is the suppression of energy absorption compared to emission in the inelastic HF transitions. Finally, by comparing the rate equation results with Monte Carlo simulations, we discuss the importance of having both HF interaction and another escape mechanism from the triplets to induce a finite DNP.Comment: 26 pages, 17 figure

    Zero-temperature spin-glass freezing in self-organized arrays of Co nanoparticles

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    We study, by means of magnetic susceptibility and magnetic aging experiments, the nature of the glassy magnetic dynamics in arrays of Co nanoparticles, self-organized in N layers from N=1 (two-dimensional limit) up to N=20 (three-dimensional limit). We find no qualitative differences between the magnetic responses measured in these two limits, in spite of the fact that no spin-glass phase is expected above T=0 in two dimensions. More specifically, all the phenomena (critical slowing down, flattening of the field-cooled magnetization below the blocking temperature and the magnetic memory induced by aging) that are usually associated with this phase look qualitatively the same for two-dimensional and three-dimensional arrays. The activated scaling law that is typical of systems undergoing a phase transition at zero temperature accounts well for the critical slowing down of the dc and ac susceptibilities of all samples. Our data show also that dynamical magnetic correlations achieved by aging a nanoparticle array below its superparamagnetic blocking temperature extend mainly to nearest neighbors. Our experiments suggest that the glassy magnetic dynamics of these nanoparticle arrays is associated with a zero-temperature spin-glass transition.Comment: 6 pages 6 figure
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