7,790 research outputs found

    El Museo Cerralbo de Madrid: desde sus orígenes a la digitalización de sus fondos.

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    Actas de las Cuartas Jornadas Imagen, Cultura y Tecnología celebradas el 4, 5 y 6 de julio de 2005 en la Universidad Carlos III de MadridPublicad

    Análisis comparativo de las bibliotecas online de San Millán de la Cogolla y la Abadía de Montserrat

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    Actas de las Quintas Jornadas Imagen, Cultura y Tecnología celebradas del 3 al 5 de julio de 2006 en la Universidad Carlos III de Madri

    Ontogenetic Shifts in Terrestrial Reliance of Stream-Dwelling Brown Trout

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    This study focuses on terrestrial reliance of brown trout (Salmo trutta) and compared it to the potential prey available (macrozoobenthos and drifting invertebrates) in three temperate rivers (Galicia, NW Spain), with special emphasis on variations in terrestrial energy intake through the ontogeny of brown trout. Additionally, we paid particular attention to individual variation of terrestrial resource use within and between age classes. Prey items were grouped in four categories: i) aquatic invertebrates; ii) imagoes of aquatic invertebrates; iii) terrestrial invertebrates; and iv) fish prey. Next, energy composition was measured according to dry weight-energy equations for each individual in line with above-mentioned prey categories. Our findings illustrate that terrestrial invertebrates appeared to be scarce in the environment, whereas aquatic food resources were rather abundant and accessible. The use of terrestrial invertebrates tended to increase with age, but with a high degree of inter-individual variation in resource use. In fact, the individual reliance of brown trout on terrestrial invertebrates may vary considerably (between 0% and 76.9%). Besides, the frequency of terrestrial foragers, i.e., individuals with terrestrial invertebrates in their stomachs, increased with age, except in one population which had the maximum value in the age-2 class. The acquisition of terrestrial invertebrates thus appears to be a process strongly dependent upon the actual food availability in the environment, but with a high degree of individual variance in resource use within the same age class. Finally, we discuss that terrestrial invertebrates may largely contribute to cover the energy intake of the species, highlighting the interface between terrestrial and aquatic ecosystems, and thereby the importance of riparian canopy cover as a key factor for food supply of stream-dwelling salmonids speciesThe authors would like to thank the staff of the Station of Hydrobiology of the USC ‘Encoro do Con’ for their participation in the field work. We also appreciate the constructive comments on the manuscript given by one anonymous referee. J. Sánchez-Hernández was supported by a postdoctoral grant from the Galician Plan for Research, Innovation, and Growth 2011-2015 (Plan I2C, Xunta de Galicia)S

    Submillimeter H2O masers in water-fountain nebulae

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    We report the first detection of submillimeter water maser emission toward water-fountain nebulae, which are post-AGB stars that exhibit high-velocity water masers. Using APEX we found emission in the ortho-H2O (10_29-9_36) transition at 321.226 GHz toward three sources: IRAS 15445-5449, IRAS 18043-2116 and IRAS 18286-0959. Similarly to the 22 GHz masers, the submillimeter water masers are expanding with a velocity larger than that of the OH masers, suggesting that these masers also originate in fast bipolar outflows. In IRAS 18043-2116 and IRAS 18286-0959, which figure among the sources with the fastest water masers, the velocity range of the 321 GHz masers coincides with that of the 22 GHz masers, indicating that they likely coexist. Towards IRAS 15445-5449 the submillimeter masers appear in a different velocity range, indicating that they are tracing different regions. The intensity of the submillimeter masers is comparable to that of the 22 GHz masers, implying that the kinetic temperature of the region where the masers originate should be Tk > 1000 K. We propose that the passage of two shocks through the same gas can create the conditions necessary to explain the presence of strong high-velocity 321 GHz masers coexisting with the 22 GHz masers in the same region.Comment: 4 pages, 1 figure. Accepted for publication in A&A Letter

    Analysis of the quark sector in the 2HDM-III with a four-zero Yukawa texture using the most recent data on the CKM matrix

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    In this letter we analyse, in the context of the general 2-Higgs Doublet Model, the structure of the Yukawa matrices, Y~1,2q\widetilde{ \bf Y}_{ _{1,2} }^{q}, by assuming a four-zero texture ansatz for their definition. In this framework, we obtain compact expressions for Y~1,2q\widetilde{ \bf Y}_{ _{1,2} }^{q}, which are reduced to the Cheng and Sher ansatz with the difference that they are obtained naturally as a direct consequence of the invariants of the fermion mass matrices. Furthermore, in order to avoid large flavour violating effects coming from charged Higgs exchange, we consider the main flavour constraints on the off-diagonal terms of Yukawa texture {{(χ~jq)kl\left( \widetilde{\chi}_{j}^q \right)_{kl}}} (klk\neq l). We perform a χ2\chi^2-fit based on current experimental data on the quark masses and the Cabibbo-Kobayashi-Maskawa mixing matrix VCKM{ \bf V}_{\rm CKM }. Hence, we obtain the allowed ranges for the parameters Y~1,2q\widetilde{ \bf Y}_{ _{1,2} }^{q} at 1σ\sigma for several values of tanβ\tan \beta. The results are in complete agreement with the bounds obtained taking into account constraints on Flavour Changing Neutral Currents reported in the literature.Comment: 12 pages, 1 figure. Version accepted in Phys. Lett.

    Estudio comparativo de banco de datos de imágenes

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    Actas de las Cuartas Jornadas Imagen, Cultura y Tecnología celebradas el 4, 5 y 6 de julio de 2005 en la Universidad Carlos III de MadridPublicad
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