CD Tau: a detached eclipsing binary with a solar-mass companion

We present a detailed analysis of the detached eclipsing binary CD Tau. A large variety of observational data, in form of IR photometry, CORAVEL radial velocity observations and high-resolution spectra, are combined with the published light curves to derive accurate absolute dimensions and effective temperature of the components, as well as the metal abundance of the system. We obtain: MA=1.442(16) Mo, RA=1.798(17) Ro, TeffA=6200(50) K, MB=1.368(16) Msun, RB=1.584(20) Run and TeffB=6200(50) K. The metal content of the system is determined to be [Fe/H]=+0.08(15) dex. In addition, the eclipsing binary has a K-type close visual companion at about 10-arcsec separation, which is shown to be physically linked, thus sharing a common origin. The effective temperature of the visual companion (Teff=5250(200) K) is determined from synthetic spectrum fitting, and its luminosity (log L/Lo=-0.27(6)), and therefore its radius (R=0.89(9) Ro), are obtained from comparison with the apparent magnitude of the eclipsing pair. The observed fundamental properties of the eclipsing components are compared with the predictions of evolutionary models, and we obtain good agreement for an age of 2.6 Gyr and a chemical composition of Z=0.026 and Y=0.26. Furthermore, we test the evolutionary models for solar-mass stars and we conclude that the physical properties of the visual companion are very accurately described by the same isochrone that fits the more massive components.Comment: 9 pages, 6 figures, accepted for publication in MNRA

Cultural dissemination and interactive audiovisual commucation

Interactive electronic systems are generating specific ways of knowledge transmission. As always, when a new medium appears some of these ways come from pre-existing ones, whilw others are original. In this article we will sum up our view of this process and apply it to several examples of interactive audiovisual communication in general and web connectivity in particular, can add to knowledge transission procesess

Análisis de los factores de decisión y las preferencias familiares en dos escuelas diferenciadas

Treballs Finals del Grau de Sociologia, Facultat d'Economia i Empresa, Universitat de Barcelona, Curs: 2016-2017 , Tutor: Sandra Escapa Solanas(spa) La escuela diferenciada es un modelo educativo, puesto en práctica en multitud de países y ampliamente estudiado durante muchos años por todas las disciplinas académicas relacionadas de algún modo con la educación. Estrechamente ligado con la escuela diferenciada –especialmente en España— hay un elemento que, sin embargo, apenas ha sido objeto de interés para ese sinfín de investigaciones: la comunidad de padres y madres del alumnado. El presente trabajo hace una primera aproximación a aquello que les ha empujado a elegir la escuela diferenciada frente a todas las demás opciones, bien sea la proximidad, la religiosidad, los resultados, la ética pedagógica, etc., a través de una encuesta hecha a 323 madres y padres de las escuelas La Vall (femenina) y La Farga (masculina), en el área metropolitana de Barcelona. Los resultados muestran como el principal motivo de elección es la religiosidad de las escuelas, seguida por factores como los resultados o la proximidad, si bien también se destacan elementos por parte de los propios padres como el sistema trilingüe o la educación en valores.(eng) Single-sex school is an educational model, currently active in several countries and widely studied for many years by all those academic disciplines related in some way with education. There’s an element closely linked to single-sex school, specially in Spain, that has rarely been focused by all those investigations: the student’s parents community. This essay is a first approach to know what motivations moved them to choose single-sex school instead of all the other options, either proximity, religiosity, academic results, pedagogical ethics, etc., through a survey done to 332 fathers and mothers from two single-sex schools close to Barcelona, La Vall (girls) and La Farga (boys). Data obtained shows that the main choice reason is the school’s religiosity, followed by factors such as the academic results or the proximity, even though the parents themselves highlight others like the trilingual system or the values-based education

Difusió cultural i comunicació audiovisual interactiva

Els sistemes electrònics interactius estan generant formes específiques de transmissió de coneixements. Com sempre que apareix un nou mitjà, algunes d'aquestes formes es deriven dels mitjans preexistents, mentre que d'altres són originals. En aquest article resumirem la nostra visió d'aquest procés i l'aplicarem a diversos exemples d'aplicacions interactives off-line per tenir finalment una primera idea del que la comunicació audiovisual interactiva en general i la conectivitat en xarxa en particular poden afegir als processos de transmissió de coneixements

Factors de risc clínics de la pneumònia adquirida a la comunitat en adults : la perspectiva de base poblacional /

Consultable des del TDXtítol obtingut de la portada digitalitzadaAmb l'objectiu d'identificar els factors de risc clínics de pneumònia adquirida a la comunitat (PAC) s'ha fet un estudi de casos i controls en una població de 859.033 habitants majors de 14 anys. Es van incloure 1.336 pacients amb PAC confirmada i 1.326 controls aparellats de manera grupal per edat, sexe i centre d'atenció primària durant 1 any. Es va estimar el risc relatiu de PAC mitjançant models bivariats i multivariats de regressió logística no condicional. Les variables respiratòries associades al risc de PAC van ser la broncoscòpia i el sondatge nasogàstric, les infeccions respiratòries de vies altes, l'antecedent de pneumònia, les malalties cròniques de l'aparell respiratori, l'oxigenoteràpia, i els inhaladors anticolinèrgics i corticosteroides. Com a factors de risc del sistema cardiovascular s'observaren la insuficiència cardíaca i els tractaments relacionats, com els diürètics de la nansa i l'amiodarona. Els inhibidors dels canals del calci mostraren una reducció del risc del 33%. L'epilèpsia va incrementar el risc de PAC, mentre que els trastorns psiquiàtrics i, possiblement, l'ús de benzodiazepines el reduïen. Els inhibidors de la secreció gàstrica podrien ser factors de risc segons el moment d'inici del seu consum. El càncer i els tractaments relacionats, i la seropositivitat al VIH van ser factors de risc poblacionals. L'antecedent d'hospitalització va mostrar-se com un marcador de risc de PAC. El present estudi mostra la PAC com una malaltia infecciosa de naturalesa multicausal, amb factors clínics de risc i protectors, a partir dels quals es poden establir intervencions preventives oportunes per tal de reduir-ne la seva morbimortalitat.Con el objetivo de identificar los factores de riesgo clínicos de neumonía adquirida en la comunidad (NAC) se ha realizado un estudio de casos y controles en una población de 859.033 habitantes mayores de 14 años. Se incluyeron 1.336 pacientes con NAC confirmada y 1.326 controles apareados de forma grupal por edad, sexo y centro de atención primaria. Se estimó el riesgo relativo de NAC mediante modelos bivariados y multivariados de regresión logística no condicional. Las variables respiratorias asociadas al riesgo de NAC fueron la broncoscopia y el sondaje nasogástrico, las infecciones respiratorias de vías altas, el antecedente de neumonía, las enfermedades crónicas del aparato respiratorio, la oxigenoterapia, y los inhaladores anticolinérgicos y corticosteroides. Como factores de riesgo cardiovasculares se observaron la insuficiencia cardíaca y los tratamientos relacionados, como los diuréticos del asa y la amiodarona. Los inhibidores de los canales del calcio mostraran una reducción del riesgo del 33%. La epilepsia incrementó el riesgo de NAC, mientras que los trastornos psiquiátricos y, posiblemente, el uso de benzodiazepinas lo redujeron. Los inhibidores de la secreción gástrica podrían ser factores de riesgo según el momento de inicio de su consumo. El cáncer y los tratamientos relacionados, y la seropositividad al VIH fueron factores de riesgo poblacionales. El antecedente de hospitalización se mostró como un marcador de riesgo de NAC. El presente estudio muestra la NAC como una enfermedad infecciosa de naturaleza multicausal, con factores clínicos de riesgo y protectores, a partir de los cuales se pueden establecer intervenciones preventivas oportunas para reducir su morbimortalidad.With the aim of identifying clinical risk factors of community-acquired pneumonia (CAP) a case-control study was conducted in a population of 859,033 inhabitants over 14 years. We included 1,336 patients with confirmed CAP and 1,326 controls frequency matched by age, sex and primary health care centre. The relative risk of CAP was estimated through bivariate and multivariate logistic regression models. The respiratory variables associated with the risk of CAP were bronchoscopy and nasogastric tube, upper airway respiratory infections, history of pneumonia, chronic respiratory diseases, oxygen therapy, and anticholinergic and coricosteroid inhalers. As cardiovascular risk factors we observed the heart failure and its related treatments such as loop diuretics and amiodarone. Calcium channel antagonist showed a risk reduction of 33%. The epilepsy increased the risk of CAP, while psychiatric disorders, and possibly the use of benzodiazepines reduced it. Gastric-acid suppressive drugs could be risk factors depending on the time of onset of their consumption. Cancer and related treatments, and HIV seropositivity were population risk factors. The history of hospitalisation was a risk marker of CAP. This study shows the CAP as an infectious disease of multicausal nature, with clinical factors of risk and protection, from which we can establish appropriate preventive interventions to reduce its morbidity and mortality

The full spectral radiative properties of Proxima Centauri

The discovery of Proxima b, a terrestrial temperate planet, presents the opportunity of studying a potentially habitable world in optimal conditions. A key aspect to model its habitability is to understand the radiation environment of the planet in the full spectral domain. We characterize the X-rays to mid-IR radiative properties of Proxima with the goal of providing the top-of-atmosphere fluxes on the planet. We also aim at constraining the fundamental properties of the star. We employ observations from a large number of facilities and make use of different methodologies to piece together the full spectral energy distribution of Proxima. In the high-energy domain, we pay particular attention to the contribution by rotational modulation, activity cycle, and flares so that the data provided are representative of the overall radiation dose received by the atmosphere of the planet. We present the full spectrum of Proxima covering 0.7 to 30000 nm. The integration of the data shows that the top-of-atmosphere average XUV irradiance on Proxima b is 0.293 W m^-2, i.e., nearly 60 times higher than Earth, and that the total irradiance is 877+/-44 W m^-2, or 64+/-3% of the solar constant but with a significantly redder spectrum. We also provide laws for the XUV evolution of Proxima corresponding to two scenarios. Regarding the fundamental properties of Proxima, we find M=0.120+/-0.003 Msun, R=0.146+/-0.007 Rsun, Teff=2980+/-80 K, and L=0.00151+/-0.00008 Lsun. In addition, our analysis reveals a ~20% excess in the 3-30 micron flux of the star that is best interpreted as arising from warm dust in the system. The data provided here should be useful to further investigate the current atmospheric properties of Proxima b as well as its past history, with the overall aim of firmly establishing the habitability of the planet.Comment: 12 pages, 5 figures, accepted for publication in Astronomy & Astrophysic