847 research outputs found

    Blood–brain barrier and foetal-onset hydrocephalus, with a view on potential novel treatments beyond managing CSF flow

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    [EN] Despite decades of research, no compelling non-surgical therapies have been developed for foetal hydrocephalus. So far, most efforts have pointed to repairing disturbances in the cerebrospinal fluid (CSF) flow and to avoid further brain damage. There are no reports trying to prevent or diminish abnormalities in brain development which are inseparably associated with hydrocephalus. A key problem in the treatment of hydrocephalus is the blood–brain barrier that restricts the access to the brain for therapeutic compounds or systemically grafted cells. Recent investigations have started to open an avenue for the development of a cell therapy for foetal-onset hydrocephalus. Potential cells to be used for brain grafting include: (1) pluripotential neural stem cells; (2) mesenchymal stem cells; (3) geneticallyengineered stem cells; (4) choroid plexus cells and (5) subcommissural organ cells. Expected outcomes are a proper microenvironment for the embryonic neurogenic niche and, consequent normal brain development

    Análisis del relieve y cartografía de procesos geomorfológicos activos mediante SIG en la zona de confluencia de los ríos Tuerto y Porquera (provincia de León, España)

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    La configuración del relieve terrestre y los cambios que tienen lugar en el entorno natural de los asentamientos humanos tienen una gran trascendencia social y económica debido a que marcan las condiciones de habitabilidad y desarrollo futuro de las actividades antrópicas. Partiendo de este hecho, el principal objetivo de este estudio es la realización de una cartografía geomorfológica en la cual aparezcan reflejados los principales procesos activos de tipo geológico, como base para la realización en el futuro de estudios de susceptibilidad de riesgos geológicos y determinar las zonas en las que la ocupación humana pueda verse afectada por daños relacionados con procesos naturales relacionados con el medio físico. Para la elaboración de esta cartografía geomorfológica se han realizado tareas de fotointerpretación en visión estereoscópica y representación en un Sistema de Información Geográfica (ArcGis 10.1), utilizando como base el Modelo Digital del Terreno MDT05/MDT05-LIDAR con una resolución espacial de 5x5 metros, aplicando distintas herramientas, utilizando también la capa de la BCN25 de curvas de nivel, así como trabajo de campo de comprobación y descripción del relieve y procesos activos. En el mapa obtenido se pueden distinguir tres tipos de dominios geomorfológicos, cada uno con sus procesos geológicos activos predominantes: dominio paleozoico con procesos gravitacionales, dominio neógeno con procesos gravitacionales y de erosión y, por último, dominio fluvial con presencia de abanicos aluviales y llanuras de inundación principalmente

    The role of stellar radial motions in shaping galaxy surface brightness profiles

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    Aims. The physics driving features such as breaks observed in galaxy surface brightness (SB) profiles remains contentious. Here, we assess the importance of stellar radial motions in shaping their characteristics. Methods. We use the simulated Milky Way-mass cosmological discs from the Ramses Disc Environment Study (RaDES) to characterise the radial redistribution of stars in galaxies displaying type-I (pure exponentials), II (downbending), and III (upbending) SB profiles. We compare radial profiles of the mass fractions and the velocity dispersions of different sub-populations of stars according to their birth and current location. Results. Radial redistribution of stars is important in all galaxies regardless of their light profiles. Type-II breaks seem to be a consequence of the combined effects of outward-moving and accreted stars. The former produce shallower inner profiles (lack of stars in the inner disc) and accumulate material around the break radius and beyond, strengthening the break; the latter can weaken or even convert the break into a pure exponential. Further accretion from satellites can concentrate material in the outermost parts, leading to type-III breaks that can coexist with type-II breaks, but situated further out. Type-III galaxies would be the result of an important radial redistribution of material throughout the entire disc, as well as a concentration of accreted material in the outskirts. In addition, type-III galaxies display the most efficient radial redistribution and the largest number of accreted stars, followed by type-I and II systems, suggesting that type-I galaxies may be an intermediate case between types-II and III. In general, the velocity dispersion profiles of all galaxies tend to flatten or even increase around the locations where the breaks are found. The age and metallicity profiles are also affected, exhibiting different inner gradients depending on their SB profile, being steeper in the case of type-II systems (as found observationally). The steep type-II profiles might be inherent to their formation rather than acquired via radial redistribution

    Evaluación de la biosorción de cobre con cáscara de almendra

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    En este trabajo se analiza el potencial de la cáscara de almendra para su utilización como biosorbente de cobre presente en disoluciones acuosas. En primer lugar, se realizó una caracterización físico-química del biosorbente. Así, se ha determinado que los poros que posee la cáscara de almendra son mesoporos, con un ancho deporo medio de 54,5 Å y que la cantidad total de grupos activos es de 0,592 mmol/g, siendo el grupo carboxílico el mayoritario. A continuación, se analizó la influencia de las principales variables que intervienen en el proceso de biosorción. Se ha encontrado que el pH es uno de los parámetros más importantes que controlan la eliminación de cobre con cáscara de almendra, obteniéndose la máxima eficiencia del proceso a pH=5. El estudio cinético reveló que, en general, el proceso es rápido, aunque puede dividirse en dos etapas, una primera más rápida (primeros 20 minutos) y otra segunda etapa donde el proceso transcurre de forma más lenta. Se ha encontrado que el modelo de pseudo-segundo orden reproduce de forma adecuada el proceso. Por otra parte, el estudio del equilibrio mostró que a medida que aumenta la concentración inicial de cobre, se eleva la capacidad de biosorción del sólido hasta alcanzar un valor prácticamente constante para concentraciones superiores a 100 mg/L. El modelo de Langmuires el que mejor reproduce los resultados experimentales, obteniéndose una capacidad máxima de biosorción decobre de 9,44 mg/g

    On the Environmental Dependence of Cluster Galaxy Assembly Timescale

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    We present estimates of CN and Mg overabundances with respect to Fe for early-type galaxies in 8 clusters over a range of richness and morphology. Spectra were taken from the Sloan Digital Sky Survey (SDSS) DR1, and from WHT and CAHA observations. Abundances were derived from absorption lines and single burst population models, by comparing galaxy spectra with appropriately broadened synthetic model spectra. We detect correlations between [Mg/CN] and [CN/Fe] and cluster X-ray luminosity. No correlation is observed for [Mg/Fe]. We also see a clear trend with the richness and morphology of the clusters. This is interpreted given varying formation timescales for CN, Mg and Fe, and a varying star formation history in early-type galaxies as a function of their environment: intermediate-mass early-type galaxies in more massive clusters are assembled on shorter timescales than in less massive clusters, with an upper limit of ~1 Gyr.Comment: Accepted for publication in ApJ Letter

    Does Rising Income Inequality Reduce Life Expectancy?: New Evidence for 26 European Countries (1995-2014)

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    An open debate these days is about how national income inequality could affect individuals? health outcomes. Therefore, the present study aims to provide new evidence regarding life expectancy determinants and how they are related to the income inequality hypothesis. Precisely, it is provided new evidence on this relationship for 26 European countries during the period 1995?2014. The analysis is based on panel data techniques, with the latest data from both Eurostat and the OECD Health Statistics. Furthermore, data from the World Bank is also applied. Besides, we have tested the sensitivity of the estimates in our empirical analysis using three clusters of countries. Our results suggest that income inequality does not significantly reduce health in developed societies, like the European ones. Notwithstanding, as income inequality can be sometimes harmful for population health, these issues must be taken into account in order to improve health care policies

    Sex-moderated socio-labor aspects as mediators of a cognitive stimulation program in older adults: randomized clinical trial

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    Cognitive stimulation is essential for successful aging. The influence of sex and socio-occupational elements on this area remains unknown. This study aimed to analyze the possible mediation of those elements in the effectiveness of a cognitive stimulation program in primary care. A randomized clinical trial was conducted with 232 adults aged 65 years or older without cognitive impairment. The intervention produced significant cognitive improvements. Women improved independently of social and occupational factors, while men’s improvement occurred at a low role level (zero to one), a medium level of interests (two to three), with a medium level of mental occupation (neither high nor low), and with marked personal values. The mediating variables were the intervention group in both sexes and, also in men, a low and medium role level. Therefore, the intervention and roles appear as mediating variables moderated by sex. In conclusion, cognitive stimulation programs should be adapted

    Combination of DROOL rules and Protégé knowledge bases in the ONTO-H annotation tool

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    ONTO-H is a semi-automatic collaborative tool for the semantic annotation of documents, built as a Protégé 3.0 tab plug-in. Among its multiple functionalities aimed at easing the document annotation process, ONTO-H uses a rule-based system to create cascading annotations out from a single drag and drop operation from a part of a document into an already existing concept or instance of the domain ontology being used for annotation. It also gives support to the detection of name conflicts and instance duplications in the creation of the annotations. The rule system runs on top of the open source rule engine DROOLS and is connected to the domain ontology used for annotation by means of an ad-hoc programmed Java proxy
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