20 resultados para hole expansion test


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En el siguiente estudio se analiza, mediante el test de 20 minutos, la mejora en el rendimiento de diez remeros pertenecientes a un club de elite. Estos sujetos, se sometieron a dos test en diferentes fechas de la temporada. Se hizo una comparación entre ambas pruebas. Las variables analizadas en esa comparación y que muestran la evolución de los deportistas son las siguientes: wattios, ritmo y frecuencia cardiaca. Analizando los wattios se calculó la potencia obtenida durante todo el test, con el ritmo nos referimos a las paladas por minuto y mirando la frecuencia cardiaca pudimos obtener dos indicadores: cuál es el porcentaje de la frecuencia cardiaca máxima con la que cada deportista realizó la prueba y en qué medida recuperaba cada sujeto.

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Al inicio del plan de tutorización que se ha llevado a cabo durante el presente curso 2014-2015, la idea que plantee, se relacionaba con aspectos del ámbito del entrenamiento de la actividad física, y más concretamente con el entrenamiento personal o personal coaching. Esta primera propuesta, debatida en las primeras reuniones con el tutor, fue descartada, y a posteriori, inicie un proceso de reflexión conjuntamente y bajo las directrices del tutor del trabajo, en el ámbito de la especificidad del trabajo de fuerza. Este trabajo de reflexión concluyó en la primera etapa del proceso de tutorización con la propuesta de un título provisional en relación al análisis comparado en los ejercicios de tracción con elementos elásticos y con carga fija, título inicial, que ha prefijado la estrategia del trabajo de fin de grado

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First-principles calculations for the temporal characteristics of hole-phonon relaxation in the valence band of titanium dioxide and zinc oxide have been performed. A first-principles method for the calculations of the quasistationary distribution function of holes has been developed. The results show that the quasistationary distribution of the holes in TiO2 extends to an energy level approximately 1eV below the top of the valence band. This conclusion in turn helps to elucidate the origin of the spectral dependence of the photocatalytic activity of TiO2. Analysis of the analogous data for ZnO shows that in this material spectral dependence of photocatalytic activity in the oxidative reactions is unlikely.

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The stone marten is a widely distributed mustelid in the Palaearctic region that exhibits variable habitat preferences in different parts of its range. The species is a Holocene immigrant from southwest Asia which, according to fossil remains, followed the expansion of the Neolithic farming cultures into Europe and possibly colonized the Iberian Peninsula during the Early Neolithic (ca. 7,000 years BP). However, the population genetic structure and historical biogeography of this generalist carnivore remains essentially unknown. In this study we have combined mitochondrial DNA (mtDNA) sequencing (621 bp) and microsatellite genotyping (23 polymorphic markers) to infer the population genetic structure of the stone marten within the Iberian Peninsula. The mtDNA data revealed low haplotype and nucleotide diversities and a lack of phylogeographic structure, most likely due to a recent colonization of the Iberian Peninsula by a few mtDNA lineages during the Early Neolithic. The microsatellite data set was analysed with a) spatial and non-spatial Bayesian individual-based clustering (IBC) approaches (STRUCTURE, TESS, BAPS and GENELAND), and b) multivariate methods [discriminant analysis of principal components (DAPC) and spatial principal component analysis (sPCA)]. Additionally, because isolation by distance (IBD) is a common spatial genetic pattern in mobile and continuously distributed species and it may represent a challenge to the performance of the above methods, the microsatellite data set was tested for its presence. Overall, the genetic structure of the stone marten in the Iberian Peninsula was characterized by a NE-SW spatial pattern of IBD, and this may explain the observed disagreement between clustering solutions obtained by the different IBC methods. However, there was significant indication for contemporary genetic structuring, albeit weak, into at least three different subpopulations. The detected subdivision could be attributed to the influence of the rivers Ebro, Tagus and Guadiana, suggesting that main watercourses in the Iberian Peninsula may act as semi-permeable barriers to gene flow in stone martens. To our knowledge, this is the first phylogeographic and population genetic study of the species at a broad regional scale. We also wanted to make the case for the importance and benefits of using and comparing multiple different clustering and multivariate methods in spatial genetic analyses of mobile and continuously distributed species.

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MP2/aug-cc-pVTZ calculations were performed on complexes of aluminium and boron trihydrides and trihalides with acetylene and ethylene. These complexes are linked through triel bonds where the triel center (B or Al) is characterized by the Lewis acid properties through its -hole region while -electrons of C2H2 or C2H4 molecule play the role of the Lewis base. Some of these interactions possess characteristics of covalent bonds, i.e., the Al--electrons links as well as the interaction in the BH3-C2H2 complex. The triel--electrons interactions are classified sometimes as the 3c-2e bonds. In the case of boron trihydrides, these interactions are often the preliminary stages of the hydroboration reaction. The Quantum Theory of Atoms in Molecules as well as the Natural Bond Orbitals approach are applied here to characterize the -hole--electrons interactions.