2,433 research outputs found

    Sobre el substrato mediterráneo occidental

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    Correlación entre la variable decomiso total por causas anatomopatológicas en canales de ciervo y sus posibles causas

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    El objetivo de este trabajo es el valorar la influencia de ciertos factores^ en la aparición de lesiones nodulosas caseosas en canales de ciervo, así como determinar y evaluar el grado de eficacia del saneamiento con respecto a ia aparición de estos nodulos. Para ello se realiza una base con datos de las 52 fincas existentes en el área de estudio, que ocupa la zona norte del Distrito Sanitario de Andújar y abarca una extensión de 80.000 Has. El área pertenece a los términos municipales de Andújar, Marmolejo y Vva, de ía Reina. De todo ello, unas 61.000 están ubicadas en el Parque Natural "Sierra de Andújar". En esta base de datos se anota la procedencia, peso, sexo, resultado de la inspección sanitaria de la canal de cada ciervo y sobre todo la finca de procedencia. Estas fincas ya se han catalogado según el peso medio de sus canales, la presencia de ganado en ellas o en sus proximidades, la densidad poblacional teniendo en cuenta la relación n° de Hectáreas/n0 de ciervos abatidos. Se trata de investigar la población de ciervos existente en estas fincas. Encontramos una correlación significativa entre la presencia o proximidad de ganado y la aparición de lesiones nodulosas caseosas en las canales de ciervo; que estas lesiones se presentan en menor cuantía cuando el ganado ha sido sometido a un programa de Saneamiento por tuberculinización y además se relaciona la aparición de nodulos con una mayor densidad poblacional. De esta forma se llega a la conclusión de que la presencia de ganado y las altas densidades poblacionales influyen negativamente en la salud de una población de ciervos y que el saneamiento del ganado favorece ia salud de estos

    Direct vs. indirect optical recombination in Ge films grown on Si substrates

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    The optical emission spectra from Ge films on Si are markedly different from their bulk Ge counterparts. Whereas bulk Ge emission is dominated by the material's indirect gap, the photoluminescence signal from Ge films is mainly associated with its direct band gap. Using a new class of Ge-on-Si films grown by a recently introduced CVD approach, we study the direct and indirect photoluminescence from intrinsic and doped samples and we conclude that the origin of the discrepancy is the lack of self-absorption in thin Ge films combined with a deviation from quasi-equilibrium conditions in the conduction band. The latter is confirmed by a simple model suggesting that the deviation from quasi-equilibrium is caused by the much shorter recombination lifetime in the films relative to bulk Ge

    Dung beetle diversity and functions suggest no major impacts of cattle grazing in the Brazilian Pantanal wetlands

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    1. Dung beetles perform relevant ecological functions in pastures, such as dung removal and parasite control. Livestock farming is the main economic activity in the Brazilian Pantanal. However, the impact of cattle grazing on the Pantanal's native dung beetle community, and functions performed by them, is still unknown. 2. This study evaluated the effects of cattle activity on dung beetle community attributes (richness, abundance, biomass, composition, and functional group) as well as their ecological functions (dung removal and soil bioturbation) in the Pantanal. In January/February 2016, dung beetles were sampled and their ecological functions measured in 16 sites of native grasslands in Aquidauana, Mato Grosso do Sul, Brazil, 10 areas regularly grazed by cattle and six control ungrazed areas (> 20 years of abandonment). 3. In all, 1169 individuals from 30 species of dung beetles were collected. Although abundance, species richness, and biomass did not differ between grasslands with and without cattle activity, species composition and functional groups differed among systems. Large roller beetles were absent from non-cattle grasslands, and the abundance, richness, and biomass of medium roller beetles was higher in those systems. 4. Despite causing changes in species/functional group composition, the results of this study show that a density compensation of functional groups in cattle-grazed natural grasslands seems to have conserved the ecological functions (dung removal and soil bioturbation), with no significant differences between systems. 5. Therefore, these results provide evidence that cattle breeding in natural grasslands of the Brazilian Pantanal can integrate livestock production with the conservation of the dung beetle community and its ecological functions. © 2019 The Royal Entomological Societ

    Resonant Raman scattering off neutral quantum dots

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    Resonant inelastic (Raman) light scattering off neutral GaAs quantum dots which contain a mean number, N=42, of electron-hole pairs is computed. We find Raman amplitudes corresponding to strongly collective final states (charge-density excitations) of similar magnitude as the amplitudes related to weakly collective or single-particle excitations. As a function of the incident laser frequency or the magnetic field, they are rapidly varying amplitudes. It is argued that strong Raman peaks should come out in the spin-density channels, not related to valence-band mixing effects in the intermediate states.Comment: Accepted in Physical Review

    Inestabilidad de laderas en el Valle del Meredal (Asturias, NO de España)

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    [Resumen] En el valle del Meredal se han identificado 64 movimientos en masa que incluyenmovimientos complejos, deslizamientos rotacionales, flujos y avalanchas rocosas, cuyo desarrollo está condicionado por el diferente comportamiento mecánico de los materiales del sustrato. La aplicación de distintos criterios de cronología relativa basados en el grado de superposición y conservación de las formas ha permitido diferenciar cinco clases de movimientos en masa en cuanto a su edad. Desde el punto de vista regional, la incisión de la red fluvial asociada a los cambios climáticos cuaternarios y a la elevación del margen cantábrico parece ser el factor determinante del origen de esta dinámica.[Abstract] In the Meredal valley 64 landslides, including complex movements, rock slumps,flows and rock avalanches have been identified. The development of these landslides is conditioned by the mechanical behaviour of the different bedrock lithologies. Five chronological classes of movements have been established by applying several relative chronology criteria, as superposition and preservation degree of the landslides. From the regional point of view, fluvial drainage incision linked to quaternary climate changes and to the uplift of the cantabrian margin seems to be determinant in the origin of this dynamics

    Action naming is impaired in Parkinson disease patients

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    In order to explore the possible contribution of the motor system to the representation of verbs, we studied the relative preservation of the capacity of Parkinson disease patients to name matched sets of object and action pictures. The performance of this group of participants was compared with that of a group of healthy seniors, and a group of Alzheimer disease patients. Generalized linear mixed-effects analyses showed that, whereas the two control groups had similar accuracy scores in response to objects and actions, Parkinson disease patients presented a significant impairment in their capacity to name actions compared to objects. The results of this study support the idea that verb representations are grounded in neural networks to which brain areas involved in motor control contribute

    Implementation of the iDMU for an Aerostructure Industrialization in AIRBUS

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    AbstractAIRBUS Military has undertaken a project to implement the industrial Digital Mock-Up (iDMU) concept to support the industrialization process of a medium size aerostructure. Within the framework of a collaborative engineering strategy, such project is part of the efforts to deploy Digital Manufacturing as a key technology for the industrialization of aircrafts assembly lines. The project has confirmed the potential of the iDMU to improve the industrial design process in a collaborative engineering environment. This communication presents the main project objectives, the key methodological points, the main project achievements and the next additional developments to increase the scope and benefits of the iDMU concept
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