1,093 research outputs found

    Medidas de propiedades dieléctricas de materiales de construcción mediante elipsometría

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    A set of measurements of electromagnetic properties of building materials is presented in this work. The method is based on the measurement of the polarization state of the reflected signal from the material under study at a fixed angle of incidence. From the measured data, by using the Fresnel equations, it has been obtained the dielectric constant. Measurements were done by using two horn antennas at the frequency of 9 GHz. The obtained results are compared with the free space reflexion and transmission Fresnel method and other reflection methods based on a conductor waveguide. The method explained in this work can be used for other type of materials and its main advantage is the non-destructive character and the ease implementation

    Propuesta para la Reestructuración Funcional de la Figura del Coordinador de Virtualización en la UNED

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    El sistema organizativo académico de la Universidad Nacional de Educación a Distancia (UNED) está integrado por docentes en la Sede Central y profesores tutores en los Centros Asociados repartidos por el territorio español. A partir del nuevo panorama educativo en la enseñanza universitaria europea (Espacio Europeo de Enseñanza Superior, -EEES), la UNED se fue adaptando y situándose en un escenario moderno e innovador, iniciándose la mejora y homogeneización de los servicios que reciben los estudiantes mediante los cursos virtuales. En este contexto, se precisó la formación a profesores tutores y a estudiantes en la utilización de los cursos virtuales de la universidad, surgiendo así el rol del Coordinador de Virtualización (CV). En la actualidad hay 62 coordinadores (uno por cada centro asociado). Tras la implantación de las nuevas titulaciones dentro del marco del EEES y, una vez consolidada esta figura en la institución, se ha hecho necesario ofrecer una nueva organización en las funciones y tareas que los CV han de ejercer. Este trabajo describe la nueva propuesta organizativa diseñada para su aplicación a partir del próximo curso 2014-2015, y para cuya elaboración se han seguido los siguientes pasos: identificación del tipo de tareas a desarrollar (apoyo tecnológico a estudiantes y asesoramiento a profesores tutores), establecimiento de los contextos de trabajo (presencial y virtual), y clasificación por categorías para permitir una asignación de actividades básicas a todos los CV y de actividades más especializadas entre subgrupos de CV. Palabras llave: Aprendizaje semipresencial; Formación de profesorado; Competencias tecnológicas; Habilidades digitales. Virtualization Coordinator: Trainer of Tutor-Professors and Support for Students in the UNED Associate CenterAbstract The academic organizational structure of the Universidad Nacional de Educación a Distancia (UNED) is composed of professors at Central Headquarters and tutor-professors at the Associate Centers spread across the Spanish territory. From the new educational landscape in European university education (European Higher Education Area - EHEA), UNED was adapting and placing itself in a modern and innovative stage, beginning with the improvement and standardization of services provided to students through the online courses. In this context, training for both tutor-professors and students in the use of online courses was required, and that´s how the role of Virtualization Coordinator (VC) emerged. At present time, there are 66 VCs (one for each Associate Center). After implementation of the new qualifications within the framework of the EHEA and once established this role in the institution, it is necessary to provide a new organization in the functions and tasks that have to exercise VC. This paper describes a new organizational proposal designed for use from next year 2014-2015, and to whose development we have followed the following steps: identification of the type of tasks to be performed (technical support to students and advice to tutor-professors), establishment of working contexts (presential and virtual), and categorization to allow distribution of basic activities among all the VC, and more specialized activities among subgroups of VC.Keywords: Blended learning; Teachers training; Technological competences; Digital skills

    A 3’-UTR polymorphism in soluble epoxide hydrolase gene Is associated with acute rejection in renal transplant recipients

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    Antecedentes y finalidad: Los ácidos epoxyeicosatrienoic (EETs) son metabolitos del ácido araquidónico que desempeñan una función protectora contra procesos perjudiciales que pueden ocurrir después de re-oxigenación del injerto. Decidimos investigar si la presencia de polimorfismos funcionales en el gen que codifica el epóxido hidrolasa soluble (EPHX2), que metaboliza EETs a menos compuestos activos, pueden jugar un papel importante en el resultado del trasplante renal. Métodos En un grupo de 259 receptores caucásicos de trasplante renal y 183 donantes fallecidos, se determinó la presencia de tres EPHX2 común, a saber, los SNPs rs41507953 (K55R), rs751141 (R287Q) y rs1042032 A/G. Las asociaciones con los parámetros de la función del injerto y la incidencia de rechazo agudo fueron investigados retrospectivamente durante el primer año después del injerto mediante regresión logística, ajustándose a las variables clínicas y demográficas. Resultados Los portadores del genotipo rs1042032 GG muestran significativamente menor tasa de filtración glomerular estimada (eGFR) (38.15 ± 15.57 vs. 45.99 ± 16.05; p = 0,04) y mayores valores de creatinina sérica (1,57 ± 0,58 vs. 1,30 ± 0,47 g/dL; p=0.02) un año después del injerto, en comparación con los pacientes portadores del alelo A wildtype. El mismo genotipo GG también se asoció a un mayor riesgo de rechazo agudo. Curiosamente, esta asociación fue observada por el genotipo de ambos destinatarios [o =6.34 (1.35-29.90); p = 0,015] y donantes [OR = 5.53 (1.10 - 27.80); p=0,042]. Un modelo estadístico incluyendo ambos genotipos junto con otras variables demográficas y clínicas significativas se tradujo en un aumento de la importancia de la asociación con los receptores del genotipo [OR=8,28 (1.21-74.27); p=0,031]. Conclusiones Nuestros resultados indican que la variabilidad genética en el gen metabolizante de EETs, EPHX2, pueden tener un impacto significativo en los resultados del trasplante renal de donante fallecido.Background and Purpose: Epoxyeicosatrienoic acids (EETs) are arachidonic acid metabolites that play a protective role against damaging processes that may occur after re-oxygenation of the graft. We aimed to investigate whether the presence of functional polymorphisms in the gene encoding soluble epoxy hydrolase (EPHX2), which metabolizes EETs to less active compounds, may play a role in the outcome of renal transplantation. Methods In a group of 259 Caucasian renal transplant recipients and 183 deceased donors, we determined the presence of three common EPHX2 SNPs, namely rs41507953 (K55R), rs751141 (R287Q) and rs1042032 A/G. Associations with parameters of graft function and the incidence of acute rejection were retrospectively investigated throughout the first year after grafting by logistic regression adjusting for clinical and demographic variables. Results Carriers of the rs1042032 GG genotype displayed significantly lower estimated glomerular filtration rate (eGFR) (38.15 ± 15.57 vs. 45.99 ± 16.05; p = 0.04) and higher serum creatinine values (1.57 ± 0.58 vs. 1.30 ± 0.47 g/dL; p=0.02) one year after grafting, compared to patients carrying the wildtype A-allele. The same GG genotype was also associated to increased risk of acute rejection. Interestingly, this association was observed for the genotype of both recipients [OR =6.34 (1.35-29.90); p = 0.015] and donors [OR = 5.53 (1.10- 27.80); p=0.042]. A statistical model including both genotypes along with other meaningful demographic and clinical variables resulted in an increased significance for the association with the recipients’ genotype [OR=8.28 (1.21-74.27); p=0.031]. Conclusions Our results suggest that genetic variability in the EETs-metabolizing gene, EPHX2, may have a significant impact on the outcome of deceased-donor renal transplantation.• Asociación para el Estudio y la Prevención de las Enfermedades Renales (ASEPER), Badajoz • Junta de Extremadura, Consejería de Economía, Comercio e Innovación: Proyecto GR10022 • Red de Investigación Renal - REDINREN (Instituto de Salud Carlos III – Fondo Europeo de Desarrollo Regional – FEDER) : Ayudas a Eliecer Coto García, Carmen Díaz Corte y Carlos López LarreapeerReviewe

    Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

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    The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

    Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

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    Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| < 0.03 at 95% confidence level. [Figure not available: see fulltext.

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

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    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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    Measurement of b jet shapes in proton-proton collisions at root s=5.02 TeV

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    We present the first study of charged-hadron production associated with jets originating from b quarks in proton-proton collisions at a center-of-mass energy of 5.02 TeV. The data sample used in this study was collected with the CMS detector at the CERN LHC and corresponds to an integrated luminosity of 27.4 pb(-1). To characterize the jet substructure, the differential jet shapes, defined as the normalized transverse momentum distribution of charged hadrons as a function of angular distance from the jet axis, are measured for b jets. In addition to the jet shapes, the per-jet yields of charged particles associated with b jets are also quantified, again as a function of the angular distance with respect to the jet axis. Extracted jet shape and particle yield distributions for b jets are compared with results for inclusive jets, as well as with the predictions from the pythia and herwig++ event generators.Peer reviewe

    Search for Physics beyond the Standard Model in Events with Overlapping Photons and Jets

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    Results are reported from a search for new particles that decay into a photon and two gluons, in events with jets. Novel jet substructure techniques are developed that allow photons to be identified in an environment densely populated with hadrons. The analyzed proton-proton collision data were collected by the CMS experiment at the LHC, in 2016 at root s = 13 TeV, and correspond to an integrated luminosity of 35.9 fb(-1). The spectra of total transverse hadronic energy of candidate events are examined for deviations from the standard model predictions. No statistically significant excess is observed over the expected background. The first cross section limits on new physics processes resulting in such events are set. The results are interpreted as upper limits on the rate of gluino pair production, utilizing a simplified stealth supersymmetry model. The excluded gluino masses extend up to 1.7 TeV, for a neutralino mass of 200 GeV and exceed previous mass constraints set by analyses targeting events with isolated photons.Peer reviewe
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