5,854 research outputs found

    Biomechanical analysis of a cranial Patient Specific Implant on the interface with the bone using the Finite Element Method

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    - New advance technologies based on reverse engineering , design and additive manufacturing, have expanded design capabilities for biomedical applications to include Patient Specific Implants (PSI). This change in design paradigms needs advanced tools to assess the mechanical performance of the product, and simulate the impact on the patient. In this work, we perform a structural analysis on the interface of a cranial PSI under static loading conditions. Based on those simulations, we have identified the regions with high stress and strain and checked the failure criteria both in the implant and the skull. We evaluate the quality of the design of the implant and determine their response given different materials, in order to ensure optimality of the final product to be manufactured

    Tensorial perturbations in the bulk of inflating brane worlds

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    In this paper we consider the stability of some inflating brane-world models in quantum cosmology. It is shown that whereas the singular model based on the construction of inflating branes from Euclidean five-dimensional anti-de Sitter space is unstable to tensorial cosmological perturbations in the bulk, the nonsingular model which uses a five-dimensional asymptotically anti-de Sitter wormhole to construct the inflating branes is stable to these perturbations.Comment: 4 pages, RevTex, to appear in Phys. Rev.

    Spectropolarimetric analysis of an active region filament. I. Magnetic and dynamical properties from single component inversions

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    The determination of the magnetic filed vector in solar filaments is possible by interpreting the Hanle and Zeeman effects in suitable chromospheric spectral lines like those of the He I multiplet at 10830 A. We study the vector magnetic field of an active region filament (NOAA 12087). Spectropolarimetric data of this active region was acquired with the GRIS instrument at the GREGOR telescope and studied simultaneously in the chromosphere with the He I 10830 A multiplet and in the photosphere with the Si I 10827 A line. As it is usual from previous studies, only a single component model is used to infer the magnetic properties of the filament. The results are put into a solar context with the help of the Solar Dynamic Observatory images. Some results clearly point out that a more complex inversion had to be done. Firstly, the Stokes VV map of He I does not show any clear signature of the presence of the filament. Secondly, the local azimuth map follows the same pattern than Stokes VV as if the polarity of Stokes VV were conditioning the inference to very different magnetic field even with similar linear polarization signals. This indication suggests that the Stokes VV could be dominated by the below magnetic field coming from the active region, and not, from the filament itself. Those and more evidences will be analyzed in depth and a more complex inversion will be attempted in the second part of this series.Comment: 18 pages, 19 figures, accepted for publication in A&

    Anti-de Sitter wormhole kink

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    The metric describing a given finite sector of a four-dimensional asymptotically anti-de Sitter wormhole can be transformed into the metric of the time constant sections of a Tangherlini black hole in a five-dimensional anti-de Sitter spacetime when one allows light cones to tip over on the hypersurfaces according to the conservation laws of an one-kink. The resulting kinked metric can be maximally extended, giving then rise to an instantonic structure on the euclidean continuation of both the Tangherlini time and the radial coordinate. In the semiclassical regime, this kink is related to the existence of closed timelike curves.Comment: 10 pages, to appear in IJMP

    Análisis de la organización funcional en el fútbol

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    De manera tradicional, el estudio de la estrategia motriz (táctica) en el fútbol se ha venido realizando tomando como referencia de partida, la distribución espacial de los jugadores al inicio de cada parte de los encuentros y las denominadas "jugadas estratégicas" o "jugadas a balón parado". Este trabajo es una investigación sobre la estrategia motriz en el fútbol, la cual tiene como referente teórico a la Praxiología motriz. Sus objetivos son el estudio de la estrategia motriz (táctica), específicamente la organización funcional: usos de los subroles estratégico motores, de los equipos, en tanto que interacción motriz; considerando también las acciones con balón y su gestió
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