483 research outputs found

    Dark Matter Subhalos in the Ursa Minor Dwarf Galaxy

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    Through numerical simulations, we study the dissolution timescale of the Ursa Minor cold stellar clump, due to the combination of phase-mixing and gravitational encounters with compact dark substructures in the halo of Ursa Minor. We compare two scenarios; one where the dark halo is made up by a smooth mass distribution of light particles and one where the halo contains 10% of its mass in the form of substructures (subhalos). In a smooth halo, the stellar clump survives for a Hubble time provided that the dark matter halo has a big core. In contrast, when the point-mass dark substructures are added, the clump survives barely for \sim 1.5 Gyr. These results suggest a strong test to the \Lambda-cold dark matter scenario at dwarf galaxy scale.Comment: accepted for publication in Ap

    Educación y cooperación para el desarrollo mediante estándares universales de accesibilidad

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    II FORO «IBEROAMÉRICA EN LA ESCENA ECONÓMICA INTERNACIONAL: INVERSIONES Y EDUCACIÓN PARA EL DESARROLLO». UNIVERSIDAD REY JUAN CARLOS, MADRID (ESPAÑA), 14 DE DICIEMBRE DE 200

    Accesibilidad a Internet: requisitos para la calidad en la docencia e investigación

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    A good Internet platform for teaching and research must be accessible, independently of the computer platform used, language and other peculiarities (personal or external). This work analyzes the current limitations of Internet access, as well as the potentialities that would represent an access being truly independent of the computer platform, discapacities, availability and speed of access, language and legislation. Thus, the benefits for a more accesible network for lecturing and investigation, overcoming the geographic location or possible discapacity, would be immediate and would have a broad impact spectrum. A more accesible Internet would enhace not only the dissemination of the information, approaching us to the 'global village', but also others aspects like university principles and values that sould be considered: an improvement of the equality of opportunities and the access to the culture and the education, that are the basis of the progress and the individual and collective liberties.Una buena plataforma de docencia e investigación en la red debe ser accesible, independientemente del entorno informático, idioma y condicionantes( personales o externos). Es este trabajo se analizan, por una parte, las limitaciones actuales que se presentan en el acceso a Internet, y por otra las potencialidades que tendría un acceso un acceso independiente de las plataforma informáticas, discapacidades, disponibilidad y velocidad de acceso, idioma y legislación. Así, los beneficios para la docencia y la investigación de una red más accesible, por encima de la localización geográfica o posible discapacidad, serán inmediatos y redundaría en otros campos. Una Internet más accesible abriría una nueva vía no sólo para la difusión de la información, acercándonos a la 'aldea global', sino también para otros aspectos de lo que entenderemos como principios y valores universitarios y que deben ser considerados: una mejora en la igualdad de oportunidades y en el acceso a la cultura y la formación, que son las bases del progreso y de las libertades tanto individuales como colectivas

    Structural, vibrational and electronic properties of alpha'-Ga2S3 under compression

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    [EN] We report a joint experimental and theoretical study of the low-pressure phase of ¿¿-Ga2S3 under compression. Theoretical ab initio calculations have been compared to X-ray diffraction and Raman scattering measurements under high pressure carried out up to 17.5 and 16.1 GPa, respectively. In addition, we report Raman scattering measurements of ¿¿-Ga2S3 at high temperature that have allowed us to study its anharmonic properties. To understand better the compression of this compound, we have evaluated the topological properties of the electron density, the electron localization function, and the electronic properties as a function of pressure. As a result, we shed light on the role of the Ga¿S bonds, the van der Waals interactions inside the channels of the crystalline structure, and the single and double lone electron pairs of the sulphur atoms in the anisotropic compression of ¿¿-Ga2S3. We found that the structural channels are responsible for the anisotropic properties of ¿¿-Ga2S3 and the A¿(6) phonon, known as the breathing mode and associated with these channels, exhibits the highest anharmonic behaviour. Finally, we report calculations of the electronic band structure of ¿¿-Ga2S3 at different pressures and find a nonlinear pressure behaviour of the direct band gap and a pressure-induced direct-to-indirect band gap crossover that is similar to the behaviour previously reported in other ordered-vacancy compounds, including ß-Ga2Se3. The importance of the single and, more specially, the double lone electron pairs of sulphur in the pressure dependence of the topmost valence band of ¿¿-Ga2S3 is stressed.The authors thank the financial support from the Spanish Research Agency (AEI) under projects MALTA Consolider Team network (RED2018-102612-T) and projects MAT2016-75586-C4-2/3-P, FIS2017-83295-P, PID2019-106383GB-42/43, and PGC2018-097520-A-100, as well as from Generalitat Valenciana under Project PROMETEO/2018/123 (EFIMAT). A. M. and P. R.-H. acknowledge computing time provided by Red Espanola de Supercomputacion (RES) and MALTA-Cluster and E. L. D. S. acknowledges Marie Sklodowska-Curie Grant No. 785789-COMEX from the European Union's Horizon 2020 research and innovation program. J. A. S. also wants to thank the Ramon y Cajal fellowship (RYC-2015-17482) for financial support. We also thank the ALBA synchrotron light source for funded experiment 2017022088 at the MSPD-BL04 beamline.Gallego-Parra, S.; Vilaplana Cerda, RI.; Gomis, O.; Lora Da Silva, E.; Otero-De-La-Roza, A.; Rodríguez-Hernández, P.; Muñoz, A.... (2021). Structural, vibrational and electronic properties of alpha'-Ga2S3 under compression. Physical Chemistry Chemical Physics. 23(11):6841-6862. https://doi.org/10.1039/d0cp06417cS68416862231

    Incidencia del ejercicio físico y el entrenamiento vibratorio sobre la amplitud de movimiento de mujeres con fibromialgia

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    Objetivo. En la presente investigación hemos planteado como objetivos principales, por un lado, valorar el efecto del ejercicio físico y el entrenamiento vibratorio sobre la amplitud de movimiento en mujeres con fibromialgia (FM) y, por otro, determinar si existe alguna relación entre dicha variable y el dolor y la rigidez. Método. La muestra estuvo constituida por un total de cuarenta y seis mujeres (edad: 58,2 ± 8,5 años; peso: 72,1 ± 9,6 kg; altura: 156,9 ± 6,1 cm) diagnosticadas con FM. Los participantes fueron divididos aleatoriamente en tres grupos: ejercicio físico y entrenamiento vibratorio (WBV + EJ; n = 15); ejercicio físico sin vibraciones (EJ; n = 15) y un grupo control (GC; n = 16). Los grupos WBV + EJ y EJ realizaron dos sesiones semanales de ejercicio físico durante 8 semanas. Además, los integrantes de WBV + EJ realizaron 3 sesiones semanales de entrenamiento vibratorio (30 Hz, 4 mm). Las pruebas de evaluación incluyeron el test de sit and reach (variable principal), la valoración del número de tender points (TP) y una escala analógica visual (VAS) para determinar la rigidez. Resultados. Los resultados derivados del análisis intra e intergrupo no mostraron diferencias significativas en la rigidez o el número de TP, si bien, la prueba de sit and reach mostró una mejora estadísticamente significativa en WBV + EJ (58%; p < 0,05). El análisis correlacional mostró una relación inversa (r = -0,55; p < 0,05) entre el sit and reach y el número de TP. Conclusión. Como conclusión, podemos indicar que los datos obtenidos en la presente investigación han mostrado los efectos significativos del entrenamiento vibratorio sobre la amplitud de movimiento en mujeres con FM, aunque el número de TP o la rigidez no se vieron afectados en ningún caso

    Menus for Feeding Black Holes

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    Black holes are the ultimate prisons of the Universe, regions of spacetime where the enormous gravity prohibits matter or even light to escape to infinity. Yet, matter falling toward the black holes may shine spectacularly, generating the strongest source of radiation. These sources provide us with astrophysical laboratories of extreme physical conditions that cannot be realized on Earth. This chapter offers a review of the basic menus for feeding matter onto black holes and discusses their observational implications.Comment: 27 pages. Accepted for publication in Space Science Reviews. Also to appear in hard cover in the Space Sciences Series of ISSI "The Physics of Accretion onto Black Holes" (Springer Publisher

    Longitudinal effects on mental health of moving to greener and less green urban areas

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    This is a freely-available open access publication. Please cite the published version which is available via the DOI link in this record.Despite growing evidence of public health benefits from urban green space there has been little longitudinal analysis. This study used panel data to explore three different hypotheses about how moving to greener or less green areas may affect mental health over time. The samples were participants in the British Household Panel Survey with mental health data (General Health Questionnaire scores) for five consecutive years, and who relocated to a different residential area between the second and third years (n = 1064; observations = 5320). Fixed-effects analyses controlled for time-invariant individual level heterogeneity and other area and individual level effects. Compared to premove mental health scores, individuals who moved to greener areas (n = 594) had significantly better mental health in all three postmove years (P = .015; P = .016; P = .008), supporting a "shifting baseline" hypothesis. Individuals who moved to less green areas (n = 470) showed significantly worse mental health in the year preceding the move (P = .031) but returned to baseline in the postmove years. Moving to greener urban areas was associated with sustained mental health improvements, suggesting that environmental policies to increase urban green space may have sustainable public health benefits.European Regional Development Fund 2007-2013European Social Fund Convergence Programme for Cornwall and the Isles of ScillyEconomic and Social Research Counci

    Loss of GPR75 protects against non-alcoholic fatty liver disease and body fat accumulation

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    Open Access via the Elsevier Agreement L.K.H. designed the experiments with input from F.M., G.S.H.Y., and J.J.R.; F.M. and J.I. created the CRISPR-Cas9-deleted Gpr75 mouse line with input from A.M.; A.L.-P., C.M., B.Y.H.L., G.K.C.D., N.S., P.B.M.d.M., R.C., K.K., E.J.G., J.R.B.P., F.G., J.R.S., and J.J.R. performed experiments and/or data analysis; D.T. provided reagents and intellectual contributions; and L.K.H. and A.L.-P. wrote the manuscript with input from all other authors.Peer reviewe
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