990 research outputs found

    Tracing the long bar with red-clump giants

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    Over the last decade a series of results have lent support to the hypothesis of the existence of a long thin bar in the Milky Way with a half-length of 4.5 kpc and a position angle of around 45 deg. This is apparently a very different structure from the triaxial bulge of the Galaxy. In this paper, we analyse the stellar distribution in the inner 4 kpc of the Galaxy to see if there is clear evidence for two triaxial or barlike structures, or whether there is only one. By using the red-clump population as a tracer of the structure of the inner Galaxy we determine the apparent morphology of the inner Galaxy. Star counts from 2MASS are used to provide additional support for this analysis. We show that there are two very different large-scale triaxial structures coexisting in the inner Galaxy: a long thin stellar bar constrained to the Galactic plane (|b|<2 deg) with a position angle of 43.1 +- 1.8 deg, and a distinct triaxial bulge that extends to at least |b|<7.5 deg with a position angle of 12.6 +- 3.2 deg. The scale height of the bar source distribution is around 100 pc, whereas for the bulge the value of this parameter is five times larger.Comment: 16 pages, 35 figures, accepted for publication in A&

    ALBAYZIN 2018 spoken term detection evaluation: a multi-domain international evaluation in Spanish

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    [Abstract] Search on speech (SoS) is a challenging area due to the huge amount of information stored in audio and video repositories. Spoken term detection (STD) is an SoS-related task aiming to retrieve data from a speech repository given a textual representation of a search term (which can include one or more words). This paper presents a multi-domain internationally open evaluation for STD in Spanish. The evaluation has been designed carefully so that several analyses of the main results can be carried out. The evaluation task aims at retrieving the speech files that contain the terms, providing their start and end times, and a score that reflects the confidence given to the detection. Three different Spanish speech databases that encompass different domains have been employed in the evaluation: the MAVIR database, which comprises a set of talks from workshops; the RTVE database, which includes broadcast news programs; and the COREMAH database, which contains 2-people spontaneous speech conversations about different topics. We present the evaluation itself, the three databases, the evaluation metric, the systems submitted to the evaluation, the results, and detailed post-evaluation analyses based on some term properties (within-vocabulary/out-of-vocabulary terms, single-word/multi-word terms, and native/foreign terms). Fusion results of the primary systems submitted to the evaluation are also presented. Three different research groups took part in the evaluation, and 11 different systems were submitted. The obtained results suggest that the STD task is still in progress and performance is highly sensitive to changes in the data domain.Ministerio de Economía y Competitividad; TIN2015-64282-R,Ministerio de Economía y Competitividad; RTI2018-093336-B-C22Ministerio de Economía y Competitividad; TEC2015-65345-PXunta de Galicia; ED431B 2016/035Xunta de Galicia; GPC ED431B 2019/003Xunta de Galicia; GRC 2014/024Xunta de Galicia; ED431G/01Xunta de Galicia; ED431G/04Agrupación estratéxica consolidada; GIU16/68Ministerio de Economía y Competitividad; TEC2015-68172-C2-1-

    Performance, structure, and mechanism of CeO<sub>2</sub> in HCl oxidation to Cl<sub>2</sub>

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    Experimental and theoretical studies reveal performance descriptors and provide molecular-level understanding of HCl oxidation over CeO2. Steady-state kinetics and characterization indicate that CeO2 attains a significant activity level, which is associated with the presence of oxygen vacancies. Calcination of CeO2 at 1173 K prior to reaction maximizes both the number of vacancies and the structural stability of the catalyst. X-ray diffraction and electron microscopy of samples exposed to reaction feeds with different O2/HCl ratios provide evidence that CeO2 does not suffer from bulk chlorination in O2-rich feeds (O2/HCl ≥ 0.75), while it does form chlorinated phases in stoichiometric or sub-stoichiometric feeds (O2/HCl ≤ 0.25). Quantitative analysis of the chlorine uptake by thermogravimetry and X-ray photoelectron spectroscopy indicates that chlorination under O2-rich conditions is limited to few surface and sub-surface layers of CeO2 particles, in line with the high energy computed for the transfer of Cl from surface to sub-surface positions. Exposure of chlorinated samples to a Deacon mixture with excess oxygen rapidly restores the original activity levels, highlighting the dynamic response of CeO2 outermost layers to feeds of different composition. Density functional theory simulations reveal that Cl activation from vacancy positions to surface Ce atoms is the most energy-demanding step, although chorine-oxygen competition for the available active sites may render re-oxidation as the rate-determining step. The substantial and remarkably stable Cl2 production and the lower of CeO2 make it an attractive alternative to RuO2 for catalytic chlorine recycling in industry

    Aplicación de un modelo para predecir las reservas de carbono orgánico en un suelo monocultivado con caña de azúcar en condiciones tropicales de cuba

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    Para la simulación del carbono orgánico del suelo se utilizó el modelo RothC26.3 (Coleman y Jenkinson, 1999), que trabaja a una escala de tiempo mensual y permite determinar el recambio mensual del C mediante procesos cinéticos de primer orden, donde las tasas de descomposición de sus cuatro reservorios activos, son moduladas por la temperatura, la humedad y la cubierta de residuos. La investigación se realizó tomando como base la información de carbono orgánico del  suelo  y rendimientos  agrícolas  de experimentos  desarrollados  en áreas  agrícolas  de la Estación Provincial de Investigaciones de la Caña de Azúcar (EPICA) ubicada en Jovellanos, provincia  Matanzas  en el periodo  comprendido entre  1981  y 2010.  Los datos  de  carbono orgánico de la capa cultivable del suelo (0-20 cm), clasificado como Ferralsol plantado con caña de azúcar, correspondientes al ciclo caña planta, sirvieron de base para parametrizar el modelo, cuyo comportamiento fue modificado por las variables climáticas, procedentes de la estación meteorológica asociada al lugar. La comparación entre los datos de carbono orgánico del suelo simulados y los observados en el período 1981-2010, resultó en que los primeros expresaron 95,58% de la varianza de los datos experimentales. Se encontró que la cantidad necesaria de carbono orgánico para mantener el nivel que tenía el suelo en 1981fue de 6,28 t ha-1 año-1. Los resultados soportan el uso del modelo RothC26.3 como una herramienta para predecir el comportamiento del COS en condiciones tropicales

    Determinación del nivel de riesgo cardiovascular en teleoperadores españoles: variables asociadas

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    Introduction. Cardiovascular pathologies are the first cause of morbidity in Spain. The risk factors that influence their appearance and evolution include socioeconomic and labor aspects. The objective was to determine the level of cardiovascular risk in telephone operators. Material and methods. Retrospective and cross-sectional study in 1215 Spanish teleoperators in the period January 2017 and December 2017 in which different parameters related to cardiovascular risk are valued (overweight-obesity scales, cardiovascular risk scales, atherogenic indices, fatty liver risk scales and metabolic syndrome among others) and the influence on them of variables such as age, sex and tobacco use. The study was approved by the Clinical Research Ethics Committee of the Balearic Islands Health Area. Results. We highlight the high prevalence of high blood pressure in males (23.94%) obesity with BMI (20%), Hypercholesterolemia (27.89%) and high risk of fatty liver (23.36%). Age is the variable that shows the greatest influence on the cardiovascular risk factors analyzed. Conclusions. Although the average age of the sample is low (35.26 years in women and 33.61 years in men) a high prevalence of hypertension, obesity with different models, metabolic syndrome, moderate and high score and REGICOR values as well as high risk of fatty liver especially in men is observed.Introducción. Las patologías cardiovasculares son la primera causa de morbimortalidad en España. Entre los factores de riesgo que influyen en su aparición y evolución se incluyen aspectos socioeconómicos y laborales. El objetivo fue determinar el nivel de riesgo cardiovascular en el colectivo de teleoperadores telefónicos. Material y métodos. Estudio retrospectivo y transversal en 1215 teleoperadores españoles en el periodo enero de 2017 y diciembre de 2017 en el que se valoran diferentes parámetros relacionados con el riesgo cardiovascular (escalas de sobrepeso-obesidad, escalas de riesgo cardiovascular, índices aterogénicos, escalas de riesgo de hígado graso y síndrome metabólico entre otros) y la influencia en ellos de variables como edad, sexo y consumo de tabaco. El estudio fue aprobado por el Comité de ética de investigación clínica del área de salud de Illes Balears. Resultados. Destacamos la alta prevalencia en varones de hipertensión arterial (23,94%) obesidad con IMC (20%), hipercolesterolemia (27,89%) y alto riesgo de hígado graso (23,36%). La edad es la variable que muestra mayor influencia en los factores de riesgo cardiovascular analizados. Conclusiones. Aunque la edad media de la muestra es baja (35,26 años en mujeres y 33,61 años en hombres) se observa una alta prevalencia de hipertensión, obesidad con los diferentes modelos, síndrome metabólico, valores moderados y altos de SCORE y REGICOR así como de alto riesgo de hígado graso especialmente en los hombres

    Cocaine promotes oxidative stress and microglial-macrophage activation in rat cerebellum

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    Different mechanisms have been suggested for cocaine neurotoxicity, including oxidative stress alterations. Nuclear factor kappa B (NF-κB), considered a sensor of oxidative stress and inflammation, is involved in drug toxicity and addiction. NF-κB is a key mediator for immune responses that induces microglial/macrophage activation under inflammatory processes and neuronal injury/degeneration. Although cerebellum is commonly associated to motor control, muscular tone, and balance. Its relation with addiction is getting relevance, being associated to compulsive and perseverative behaviors. Some reports indicate that cerebellar microglial activation induced by cannabis or ethanol, promote cerebellar alterations and these alterations could be associated to addictive-related behaviors. After considering the effects of some drugs on cerebellum, the aim of the present work analyzes pro-inflammatory changes after cocaine exposure. Rats received daily 15 mg/kg cocaine i.p., for 18 days. Reduced and oxidized forms of glutathione (GSH) and oxidized glutathione (GSSG), glutathione peroxidase (GPx) activity and glutamate were determined in cerebellar homogenates. NF-κB activity, CD68, and GFAP expression were determined. Cerebellar GPx activity and GSH/GSSG ratio are significantly decreased after cocaine exposure. A significant increase of glutamate concentration is also observed. Interestingly, increased NF-κB activity is also accompanied by an increased expression of the lysosomal mononuclear phagocytic marker ED1 without GFAP alterations. Current trends in addiction biology are focusing on the role of cerebellum on addictive behaviors. Cocaine-induced cerebellar changes described herein fit with previosus data showing cerebellar alterations on addict subjects and support the proposed role of cerebelum in addiction

    XQ-100: A legacy survey of one hundred 3.5 ≲ z ≲ 4.5 quasars observed with VLT/X-shooter

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    We describe the execution and data reduction of the European Southern Observatory Large Programme "Quasars and their absorption lines: a legacy survey of the high-redshift Universe with VLT/X-shooter" (hereafter "XQ-100"). XQ-100 has produced and made publicly available a homogeneous and high-quality sample of echelle spectra of 100 quasars (QSOs) at redshifts z ≃ 3.5-4.5 observed with full spectral coverage from 315 to 2500 nm at a resolving power ranging from R ̃. 4000 to 7000, depending on wavelength. The median signal-to-noise ratios are 33, 25 and 43, as measured at rest-frame wavelengths 1700, 3000 and 3600 Å, respectively. This paper provides future users of XQ-100 data with the basic statistics of the survey, along with details of target selection, data acquisition and data reduction. The paper accompanies the public release of all data products, including 100 reduced spectra. XQ-100 is the largest spectroscopic survey to date of high-redshift QSOs with simultaneous rest-frame UV/optical coverage, and as such enables a wide range of extragalactic research, from cosmology and galaxy evolution to AGN astrophysics. © 2016 ESO

    The bright optical afterglow of the long GRB 001007

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    We present optical follow up observations of the long GRB 001007 between 6.14 hours and ~468 days after the event. An unusually bright optical afterglow (OA) was seen to decline following a steep power law decay with index alpha = -2.03 +/- 0.11, possibly indicating a break in the light curve at t - to < 3.5 days, as found in other bursts. Upper limits imposed by the LOTIS alerting system 6.14 hours after the gamma ray event provide tentative (1.2 sigma) evidence for a break in the optical light curve. The spectral index beta of the OA yields -1.24 +/- 0.57. These values may be explained both by several fireball jet models and by the cannonball model. Fireball spherical expansion models are not favoured. Late epoch deep imaging revealed the presence of a complex host galaxy system, composed of at least two objects located 1.2" (1.7 sigma) and 1.9" (2.7 sigma) from the afterglow position.Comment: 7 pages, 5 figures, published in A&

    Estudio de la respuesta espectral en el visible de películas delgadas de ZnSe

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    In this work are presented results in the study of photoconductivity of ZnSe thin films deposited on glass substrates at different temperatures, under high vacuum using thermal evaporation technique. The effect of substrate temperature on the spectral phoEn este trabajo se presentan resultados en el estudio de la fotoconductividad de películas delgadas de ZnSe depositadas sobre sustratos de vidrio a diferentes temperaturas, bajo alto vacío utilizando la técnica de evaporación térmica. Se estudió el efect
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