137 research outputs found

    Angle-resolved photoemission study and first principles calculation of the electronic structure of GaTe

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    The electronic band structure of GaTe has been calculated by numerical atomic orbitals density-functional theory, in the local density approximation. In addition, the valence-band dispersion along various directions of the GaTe Brillouin zone has been determined experimentally by angle-resolved photoelectron spectroscopy. Along these directions, the calculated valence-band structure is in good concordance with the valence-band dispersion obtained by these measurements. It has been established that GaTe is a direct-gap semiconductor with the band gap located at the Z point, that is, at Brillouin zone border in the direction perpendicular to the layers. The valence-band maximum shows a marked \textit{p}-like behavior, with a pronounced anion contribution. The conduction band minimum arises from states with a comparable \textit{s}- \textit{p}-cation and \textit{p}-anion orbital contribution. Spin-orbit interaction appears to specially alter dispersion and binding energy of states of the topmost valence bands lying at Γ\Gamma. By spin-orbit, it is favored hybridization of the topmost \textit{p}z_z-valence band with deeper and flatter \textit{px_x}-\textit{py_y} bands and the valence-band minimum at Γ\Gamma is raised towards the Fermi level since it appears to be determined by the shifted up \textit{px_x}-\textit{py_y} bands.Comment: 7 text pages, 6 eps figures, submitted to PR

    Un nou present, un millor futur : demanda real i potencialitat de les energies renovables a Menorca

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    El creixement de la demanda elèctrica suposa impactes irreversibles en el medi ambient. L'estudi de BioERS se centra en una avaluació de la demanda real menorquina amb l'objectiu de determinar el pes actual de la producció neta i proposar un escenari mostrant la possibilitat d'assolir l'objectiu 20-20-20 marcat per la Unió Europea. Per determinar la demanda real s'ha precedit l'estudi de la producció centralitzada de la xarxa convencional i de petites instal·lacions d'autoconsum. Menorca és Reserva de la Biosfera des de 1993 i les energies renovables a l'illa només suposen el 3% de la demanda total. En aquesta dada no té en compte l'existència de nombroses petites instal·lacions d'autoabastiment d'energia elèctrica sense necessitat de connectar-se a la xarxa. L'obtenció de les dades de consum elèctric s'han aconseguit consultant fonts oficials i realitzant diverses entrevistes i enquestes amb els actors implicats de l'illa. El càlcul de la producció d'autoconsum s'ha realitzat seguint la següent metodologia: diferenciant tipologies d'instal·lació en nuclis rurals i cobertes d'hotels. Per calcular la producció en nuclis rurals s'ha determinat un perfil d'instal·lació per habitatge en funció de la connexió amb la xarxa convencional. Per calcular la producció en hotels, mitjançant ortofotomapes de Menorca de 2012, s'ha determinat la superfície d'instal·lació. Utilitzant les dades tècniques del panell fotovoltaic k-130 (130W/m2) i un aerogenerador de 3 kW; suposant 7h de sol diàries, 300 dies de sol a l'any i 1800 h de vent, la producció descentralitzada és de 3595 MWh, que suposa un estalvi en les emissions de 1400 tones de CO2 equivalent. L'escenari de futur proposa augmentar el pes de les energies renovables i reduir les emissions un 23% amb la implantació d'un parc eòlic al nord-oest de l'illa, la instal·lació de panells fotovoltaics en totes les cobertes dels hotels i la projecció d'autosuficiència a tots els nuclis rurals de Menorca.El crecimiento de la demanda eléctrica supone impactos irreversibles en el medio ambiente. El estudio de BioERS se centra en una evaluación de la demanda real menorquina con el objetivo de determinar el peso actual de la producción limpia y proponer un escenario mostrando la posibilidad de alcanzar el Objetivo 20-20-20 marcado por la Unión Europea. Para determinar la demanda real se ha precedido al estudio de la producción centralizada de la red convencional y de pequeñas instalaciones de autoconsumo. Menorca es Reserva de la Biosfera desde 1993 y las energías renovables en la isla tan solo suponen el 3% de la demanda total. En éste dato no se tiene en cuenta la existencia de numerosas pequeñas instalaciones de autoabastecimiento de energía eléctrica sin necesidad de conectarse a la red. La obtención de los datos de consumo eléctrico se han conseguido consultando fuentes oficiales y realizando diversas entrevistas y encuestas con los actores implicados de la isla. El cálculo de la producción de autoconsumo se ha realizado siguiendo la siguiente metodología: diferenciando tipologías de instalación en núcleos rurales y cubiertas de hoteles. Para calcular la producción en núcleos rurales se ha determinado un perfil de instalación por vivienda en función de la conexión con la red convencional. Para calcular la producción en hoteles, mediante ortofotomapas de Menorca de 2012, se ha determinado la superficie de instalación. Utilizando los datos técnicos del panel fotovoltaico k-130 (130W/m2) y un aerogenerador de 3kW; suponiendo 7h de sol diarias, 300 días de sol al año y 1800 h de viento, la producción descentralizada es de 3595 MWh, que supone un ahorro en las emisiones de 1400 toneladas de CO2 equivalente. El escenario de futuro propone aumentar el peso de las energías renovables y reducir las emisiones un 23% con la implantación de un parque eólico en el noroeste de la isla, la instalación de paneles fotovoltaicos en todas las cubiertas de los hoteles y la proyección de autosuficiencia a todos los núcleos rurales de Menorca.The electrical growth demand supposes an irreversible impact on the environment. BioERS study focuses on an assessment of real menorcan demand with the aim to determine the current weight of clean production and to propose a plan showing the possibility of reaching the aim 20-20-20 marked by the European Union. To determine the real demand, a study of conventional network and self consumption small facilities of centralized production was done. Menorca is a biosphere reserve since 1993 and renewable energies suppose a 3 % of the total demand in the island. This fact does not take into account the existence of small self-supply systems that aren't connected to the electricity distribution network. The electrical consumption information has been obtained consulting official sources and interviewing (involved) people from the island. A distinction of the different typologies of installations on rural cores and hotels' roofs has been realised in order to calculate the self-supply production. In addition, an installation profile per house based on the connection to the network has been established to calculate the production on rural cores. Hotels installation surfaces have been determined with the help of Menorca's 2012 orthophotomaps with the goal of calculating their production. Using photovoltaic panel k-130 (130W/m2) technical information and a wind generation of 3kW; supposing 7h of daily Sun, 300 days of Sun per year and 1800 h of wind, the decentralized production is 3595 MWh, which implies 1400 tones in CO2 equivalent emissions saving. A future scenario suggests increasing renewable energies weight and a 23% reduction of emissions with the establishment of a wind park on the northwest zone of the island, installing photovoltaic panels on every hotel's roof and projecting self-sufficiency in every rural core of Minorca

    Talleres de propuestas y sugerencias de alumnos de Grado para la mejora del Programa Docentia

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    El Proyecto tiene como objetivo la implementacion de una Cultura de Calidad en los alumnos de grados de diferentes Grados de Ciencias de la Salud. Y el estudio de posibles vias y mecanismos para aumentar la implicacion de los alumnos de la UCM en el Programa Docentia

    Effectiveness of Following Mediterranean Diet Recommendations in the Real World in the Incidence of Gestational Diabetes Mellitus (GDM) and Adverse Maternal-Foetal Outcomes: A Prospective, Universal, Interventional Study with a Single Group. The St Carlos Study

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    We reported that a Mediterranean Diet (MedDiet), supplemented with extra-virgin olive oil (EVOO) and pistachios, reduces GDM incidence and several other adverse outcomes. In order to assess its translational effects in the real world we evaluated the effect of MedDiet from 1st gestational visit in GDM rate compared with control (CG) and intervention (IG) groups from the previously referred trial. As secondary objective we also compared adverse perinatal outcomes between normoglycemic and diabetic women. This trial is a prospective, clinic-based, interventional study with a single group. 1066 eligible normoglycaemic women before 12 gestational weeks were assessed. 932 women (32.4 ± 5.2 years old, pre-gestational BMI 22.5 ± 3.5 kg/m2) received a motivational lifestyle interview with emphasis on daily consumption of EVOO and nuts, were followed-up and analysed. Binary regression analyses were used to examine the risk for each pregnancy outcome, pregnancy-induced hypertension, preeclampsia, gestational weight gain (GWG), caesarean-section, perineal trauma, preterm delivery, small (SGA) and large for gestational age (LGA), and Neonatal Intensive Care Unit admissions. GDM was diagnosed in 13.9%. This rate was significantly lower than the CG: RR 0.81 (0.73–0.93), p < 0.001 and no different from the IG: RR 0.96 (0.85–1.07), p = 0.468. GWG was lower in diabetic women (10.88 ± 6.46 vs. 12.30 ± 5.42 Kg; p = 0.013). Excessive weight gain (EWG) was also lower in GDM [RR 0.91 (0.86–0.96); p < 0.001] without a significant increase of insufficient weight gain. LGA were also lower (1 (0.8%) vs. 31 (3.9%); p < 0.05)), and SGA were similar (5 (3.8%) vs. 30 (3.7%)). LGA were associated to EWG (RR 1.61 (1.35–1.91), p < 0.001). Differences in other maternal-foetal outcomes were not found. In conclusions an early MedDiet nutritional intervention reduces GDM incidence and maternal-foetal adverse outcomes and should be universally applied as 1st line therapy. GDM might not be consider as a high risk pregnancy any longer

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