90 research outputs found

    Crossing the Gould Belt in the Orion vicinity

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    We present a study of the large-scale spatial distribution of 6482 RASS X-ray sources in approximately 5000 deg^2 in the direction of Orion. We examine the astrophysical properties of a sub-sample of ~100 optical counterparts, using optical spectroscopy. This sub-sample is used to investigate the space density of the RASS young star candidates by comparing X-ray number counts with Galactic model predictions. We characterize the observed sub-sample in terms of spectral type, lithium content, radial and rotational velocities, as well as iron abundance. A population synthesis model is then applied to analyze the stellar content of the RASS in the studied area. We find that stars associated with the Orion star-forming region do show a high lithium content. A population of late-type stars with lithium equivalent widths larger than Pleiades stars of the same spectral type (hence younger than ~70-100 Myr) is found widely spread over the studied area. Two new young stellar aggregates, namely "X-ray Clump 0534+22" (age~2-10 Myr) and "X-ray Clump 0430-08" (age~2-20 Myr), are also identified. The spectroscopic follow-up and comparison with Galactic model predictions reveal that the X-ray selected stellar population in the direction of Orion is characterized by three distinct components, namely the clustered, the young dispersed, and the widespread field populations. The clustered population is mainly associated with regions of recent or ongoing star formation and correlates spatially with molecular clouds. The dispersed young population follows a broad lane apparently coinciding spatially with the Gould Belt, while the widespread population consists primarily of active field stars older than 100 Myr. We expect the "bi-dimensional" picture emerging from this study to grow in depth as soon as the distance and the kinematics of the studied sources will become available from the future Gaia mission.Comment: 17 pages, 13 figures, 4 tables. Accepted for publication in Astronomy and Astrophysics. Abstract shortene

    Estudio comparativo de los parámetros calidad de la leche, características tecnológicas y producción quesera de la Raza Merina de Grazalema frente al cruce con razas foráneas

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    En los últimos años se están incorporando masivamente en España, en general, y en Andalucía, en particular, razas ovinas foráneas de aptitud lechera, fundamentalmente las razas Assaf, Awassi y Lacaune. Su introducción está fomentando, asimismo, la realización de cruces indiscriminados con nuestras razas ovinas autóctonas, de aptitud lechera pero de menor especialización, al menos cuantitativamente (Casas et al., 2005). El objetivo de este estudio ha sido analizar en dos grupos de animales de un mismo rebaño (ovejas puras de raza Merina de Grazalema, y ovejas cruzadas Merina de Grazalema x Awassi) las características de la producción lechera, y proceder a la elaboración de quesos para estudiar las posibles diferencias tecnológicas de los quesos derivados de ambas elaboraciones. A través del mismo se ha comprobado una mayor producción lechera de las ovejas cruzadas (167.35±13.20 kg frente a 136.84±4.25 kg) pero con un porcentaje de grasa (6.25±0.34 % frente a 8.27±0.22 %), proteína (4.71±0.14 % frente a 5.80±0.09 %) y extracto seco (10.97±0.46 % frente a 14.07±0.28 %), estadísticamente inferior. En cuanto a los parámetros de aptitud tecnológica, los valores de tiempo de coagulación medio (24.70±0.77 minutos), dureza media (dureza del coágulo a los 30 minutos) de 25.03±2.27 mm, y el rendimiento en cuajada (327.50±5.70 g/l), mostraron cifras inferiores a las referenciadas por Casas et al. (2005) para la raza ovina Merina de Grazalema. Finalmente, la velocidad de endurecimiento resultó mayor a los valores obtenidos en el trabajo citado anteriormente (4.59±0.54 min.). Por otro lado, estos mismos parámetros mostraron valores inferiores en el tiempo de coagulación (19.60±0.62 minutos), velocidad de endurecimiento (3.97±0.38 min.) y rendimiento en cuajada (290.55±6.67), mientras que la dureza media (32.85±2.03 mm) fue superior en las ovejas cruzadas, respecto a los valores encontrados en esta misma explotación para los animales puros. Como consecuencia de todo ello, el rendimiento quesero real fue del 30.25 % para las ovejas puras frente al 23.70 % de las cruzadas. Esto determina que la producción quesera real que se obtiene por oveja pura, sea superior al de la cruzada (41.38 kg queso fresco/lactación frente a los 39.70 de la cruzada)

    Different Dietary Approaches, Non-Alcoholic Fatty Liver Disease and Cardiovascular Disease: A Literature Review

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    Non-alcoholic fatty liver disease (NAFLD) is the first cause of chronic liver disease and is also associated with other harmful entities such as obesity, metabolic syndrome, dyslipidemia, and diabetes. NAFLD is a significant public health concern worldwide, impacting individuals of all ages, and its prevalence is projected to increase in the near future due to its connection with obesity. Intrinsic (genetics) and external (lifestyle) factors may also modulate NAFLD, and, in turn, may partly explain the observed relationship between NAFLD and cardiovascular disease (CVD). Although many drugs are been tested to treat NAFLD, to date, no drug has indication to specifically treat this disorder. Thus, the current management of NAFLD relies on lifestyle modifications and specifically on weight loss, physical activity, and the intake of a healthy diet. In the present narrative review, we will discuss the effects of certain dietary patterns on NAFLD incidence and progression

    Thrombosed great saphenous vein aneurysm accompanied by venous thrombosis

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    AbstractSuperficial venous aneurysms of the lower extremities are considered rare and their clinical significance is poorly defined. The purpose of this article is to report a case of a 72-year-old woman with a thrombosed great saphenous vein aneurysm along with deep venous thrombosis and review its clinical presentation, diagnosis and treatment

    Thrombosed great saphenous vein aneurysm accompanied by venous thrombosis

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    Superficial venous aneurysms of the lower extremities are considered rare and their clinical significance is poorly defined. The purpose of this article is to report a case of a 72- year-old woman with a thrombosed great saphenous vein aneurysm along with deep venous thrombosis and review its clinical presentation, diagnosis and treatment

    Coenzyme Q10 and Cardiovascular Diseases

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    Coenzyme Q10 (CoQ10), which plays a key role in the electron transport chain by providing an adequate, efficient supply of energy, has another relevant function as an antioxidant, acting in mitochondria, other cell compartments, and plasma lipoproteins. CoQ10 deficiency is present in chronic and age-related diseases. In particular, in cardiovascular diseases (CVDs), there is a reduced bioavailability of CoQ10 since statins, one of the most common lipid-lowering drugs, inhibit the common pathway shared by CoQ10 endogenous biosynthesis and cholesterol biosynthesis. Different clinical trials have analyzed the effect of CoQ10 supplementation as a treatment to ameliorate these deficiencies in the context of CVDs. In this review, we focus on recent advances in CoQ10 supplementation and the clinical implications in the reduction of cardiovascular risk factors (such as lipid and lipoprotein levels, blood pressure, or endothelial function) as well as in a therapeutic approach for the reduction of the clinical complications of CVD

    Modelado de compuestos volátiles y fenólicos y optimización de las condiciones de operación para obtener aceites de oliva virgen extra equilibrados

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    The main objective of this paper is to obtain extra virgin olive oils (EVOOs) which are balanced in volatile and phenolic compounds. An experimental design was performed and response surface methodology was applied. The factors for malaxation were: temperature 20-40 °C, time 30-90 min, and hole diameter of hammer-crusher 4.5-6.5 mm. The results show that high temperatures and small hole diameter must be used in order to obtain a higher content in phenolic compounds, while for volatile compounds a low temperature and large hole diameter must be used. The models predict that the best and more balanced EVOO are obtained with the hole diameter of greater size and a medium-low temperature. Thus, for a hammer-crusher hole diameter of 6.5 mm 337 and 356 mg/kg total HPLC phenols were obtained for malaxation temperature of 20 and 25 °C, respectively and, likewise, 12.7 and 11.5 mg/kg total LOX volatiles.El principal objetivo es obtener aceites de oliva vírgenes extra (AOVEs) equilibrados en compuestos volátiles y fenólicos. Se ha realizado un diseño experimental y aplicado metodología de superficie de respuesta. El rango de los factores de batido fue, temperatura 20-40 ºC y tiempo 30-90 min, y diámetro de orificio del molino de martillos 4,5-6,5 mm. Los resultados muestran que a altas temperaturas y pequeño diámetro de orificio se obtienen elevados contenidos en compuestos fenólicos, mientras que para volátiles se debe usar temperatura baja y orificio de gran diámetro. Los modelos predicen que el mejor y más equilibrado EVOO se obtiene con el orificio de mayor tamaño y temperatura media-baja. Así, para diámetro de orificio de 6,5 mm se obtienen 337 y 356 mg/kg de fenoles totales HPLC, para temperaturas de batido de 20 y 25 °C respectivamente y, asimismo, 12,7 y 11,5 mg/kg de volátiles totales LOX

    Process design for the manufacturing of soft X-ray gratings in single-crystal diamond by high-energy heavy-ion irradiation

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    The dataset that supports the findings of this study are archived in the Universidad Autónoma de Madrid data repository e‐cienciaDatos in https://doi.org/10.21950/ARZSJ1This paper describes in detail a novel manufacturing process for optical gratings suitable for use in the UV and soft X-ray regimes in a single-crystal diamond substrate based on highly focused swift heavy-ion irradiation. This type of grating is extensively used in light source facilities such as synchrotrons or free electron lasers, with ever-increasing demands in terms of thermal loads, depending on beamline operational parameters and architecture. The process proposed in this paper may be a future alternative to current manufacturing techniques, providing the advantage of being applicable to single-crystal diamond substrates, with their unique properties in terms of heat conductivity and radiation hardness. The paper summarizes the physical principle used for the grating patterns produced by swift heavy-ion irradiation and provides full details for the manufacturing process for a specific grating configuration, inspired in one of the beamlines at the ALBA synchrotron light source, while stressing the most challenging points for a potential implementation. Preliminary proof-of-concept experimental results are presented, showing the practical implementation of the methodology proposed herei

    Search for Associations Containing Young stars (SACY): I. Sample & Searching Method

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    We report results from a high-resolution optical spectroscopic survey aimed to search for nearby young associations and young stars among optical counterparts of ROSAT All-Sky Survey X-ray sources in the Southern Hemisphere. We selected 1953 late-type (B-V >= 0.6), potentially young, optical counterparts out of a total of 9574 1RXS sources for follow-up observations. At least one high-resolution spectrum was obtained for each of 1511 targets. This paper is the first in a series presenting the results of the SACY survey. Here we describe our sample and our observations. We describe a convergence method in the (UVW) velocity space to find associations. As an example, we discuss the validity of this method in the framework of the BetaPic Association.Comment: Accepted for publication in A&
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