887 resultados para Crack paths


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Fractal antennas have been proposed to improve the bandwidth of resonant structures and optical antennas. Their multiband characteristics are of interest in radiofrequency and microwave technologies. In this contribution we link the geometry of the current paths built-in the fractal antenna with the spectral response. We have seen that the actual currents owing through the structure are not limited to the portion of the fractal that should be geometrically linked with the signal. This fact strongly depends on the design of the fractal and how the different scales are arranged within the antenna. Some ideas involving materials that could actively respond to the incoming radiation could be of help to spectrally select the response of the multiband design.

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We have studied the main evolutionary paths among the galaxy types residing on the massive end of the Red Sequence and nearby locations on the Green Valley during the last ∼9 Gyr. The morphological and star formation properties of a sample of these galaxies at 0 . 3 < z < 1 .5 with stellar masses M_∗ > 5 × 10^10 M_⊙ have been analysed. We present direct observational evidence for the first time of the existence of two main evolutionary paths among the different red galaxy types since z ∼ 1 .5, which provide some clues on the nature of the processes that have governed the assembly of present-day massive quiescent galaxies. The results are in excellent agreement with the hierarchical evolutionary framework proposed in the Eliche-Moral et al. (2010) model. Data from SHARDS (one of the ESO/GTC Large Programmes approved in 2009A) will complement and improve the present findings, shedding some light into many of the still unsettled questions concerning the migration of galaxies from the Blue Cloud to the Red Sequence at z < 1 .5.

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The purpose of this research report is to present an overview of an ongoing, international project designed to chart the developmental paths and activities of sport coaches. This brief report includes three sections: (a) conceptual framework used to guide the project, (b) project design and methodology, and (c) results from pilot studies with a sample of 15 successful coaches working in different sport contexts in the United States Unlike the findings for athletic profiles, where several trends across coaching contexts were evident, only one trend was found in how these diverse groups of coaches invested their time in coach developmental activities. In relation to other coaching activities very little time was devoted to formal coach education on an annual basis. The results reinforce the need to consider the coaching context when examining coach development and when designing coach development initiatives.

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Tese de doutoramento, Biologia (Biologia Evolutiva), Universidade de Lisboa, Faculdade de Ciências, 2016

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Any analysis of the prospects for stability and sustainability in the states of Syria and Lebanon reveals the strong ties that exist between these two countries and the impact of external influences on their overall development. Their trajectories, while starkly divergent in terms of the challenges confronting them at present, converge on a path of long-term unsustainability. Lebanon is in the midst of yet another transition phase, triggered by the collapse of Hariri’s government in January 2011. The current situation might be described as one of deteriorating status quo; the state is performing poorly in terms of its delivery of fundamental public services and its institutional legitimacy is tenuous in the face of emerging para-state structures and latent (occasionally active) violence. In Syria, challenges to the sustainability of the state have evolved dramatically since the beginning of 2011, and are now nearing a tipping point. In view of the mounting unrest and violence in the country, the future prospects for its economic and political development are dim. More ominously, the risk of widespread conflict, with sectarian overtones, cannot be discounted.

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The FANOVA (or “Sobol’-Hoeffding”) decomposition of multivariate functions has been used for high-dimensional model representation and global sensitivity analysis. When the objective function f has no simple analytic form and is costly to evaluate, computing FANOVA terms may be unaffordable due to numerical integration costs. Several approximate approaches relying on Gaussian random field (GRF) models have been proposed to alleviate these costs, where f is substituted by a (kriging) predictor or by conditional simulations. Here we focus on FANOVA decompositions of GRF sample paths, and we notably introduce an associated kernel decomposition into 4 d 4d terms called KANOVA. An interpretation in terms of tensor product projections is obtained, and it is shown that projected kernels control both the sparsity of GRF sample paths and the dependence structure between FANOVA effects. Applications on simulated data show the relevance of the approach for designing new classes of covariance kernels dedicated to high-dimensional kriging.