998 resultados para Active straight leg raising


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A new practical method to generate a subspace of active coordinates for quantum dynamics calculations is presented. These reduced coordinates are obtained as the normal modes of an analytical quadratic representation of the energy difference between excited and ground states within the complete active space self-consistent field method. At the Franck-Condon point, the largest negative eigenvalues of this Hessian correspond to the photoactive modes: those that reduce the energy difference and lead to the conical intersection; eigenvalues close to 0 correspond to bath modes, while modes with large positive eigenvalues are photoinactive vibrations, which increase the energy difference. The efficacy of quantum dynamics run in the subspace of the photoactive modes is illustrated with the photochemistry of benzene, where theoretical simulations are designed to assist optimal control experiments

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In the past 2009/10 academic year, we took steps towards introduction of active methodologies, from a multidisciplinar approach, into a conventional lecture-based Dental Education program. We consolidated these practices in the current 2010/11 year, already within a new Bologna-adapted scheme. Transition involved (i) critical assessment of the limitations of traditional teaching (ii) identification of specific learning topics allowing for integration of contents, (iii) implementation of student-centred learning activities in old curricular plans (iv) assessment of students' satisfaction and perceived learning outcomes, (v) implementation of these changes in new Bologna-adapted curricula

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Las preguntas por los métodos en ciencias sociales parecen responderse con facilidad en los manuales, el simple ejercicio de definir el enfoque que utilizaremos (cuantitativo o cualitativo) supone la apertura a la claridad. En este sentido los cuestionamientos acerca de qué es lo que vamos a estudiar, por cuánto tiempo, quiénes conformarán nuestra muestra, cómo abordaremos a los sujetos de estudio, qué tipo de preguntas, encuestas o modalidades de conversación grupales aplicaremos, de qué modo validaremos nuestros resultados y tantas otras preguntas, aparecen como estrategias y técnicas metodológicas con simulaciones contextuales que en muchos aspectos aclaran los tecnicismos, pero que no agotan las múltiples críticas y preguntas que dichos métodos también presentan. En los métodos de manual, particularmente la etnografía, las estrategias aparecen unas seguidas de otras como una multiplicidad de opciones a la mano que podemos elegir según el imaginario que hemos proyectado inicialmente. Siguiendo las pautas tendemos a olvidar que los sujetos de estudio son personas hombres y mujeres que piensan, accionan y reaccionan de distintos modos afectando las metodologías y estrategias seleccionadas, de tal modo que el manual debe ser siempre el repertorio de opciones posibles de modificarse, nunca la guía final de nuestros estudios. Estos cuestionamientos acompañaron muchos de mis procesos y experiencias con los métodos de campo, a partir de los cuales presentaré algunos aspectos que me parece interesante exponer.

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Eight years have passed since the EU launched its European Neighbourhood Policy, aimed at inducing its neighbours to the east to converge on modern European values and economic norms. In this Commentary, Michael Emerson reflects on the curious and circuitous turn of events in the region during this period. Michael Emerson is Senior Associate Research Fellow at CEPS.

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This paper explains the conflictive and cooperative elements of energy diplomacy between the European Union (EU) and Russia. It argues that interdependence forms the underlying principle of this relationship and creates both sensitivity and vulnerability for the interdependent parties, thus carrying the sperms of both conflict and cooperation. Both sides would be negatively affected by the other side’s noncooperation within the current policy framework and the prevailing mistrust and recurring tensions can be explained by this sensitivity. However, even if both sides’ policies were adjusted, vulnerability interdependence would still prevent them from seriously reducing their energy cooperation. It is necessary then to see how EU and Russian energy diplomacy can converge and how their strategic energy partnership can be cemented.

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A new algorithm is described for refining the pose of a model of a rigid object, to conform more accurately to the image structure. Elemental 3D forces are considered to act on the model. These are derived from directional derivatives of the image local to the projected model features. The convergence properties of the algorithm is investigated and compared to a previous technique. Its use in a video sequence of a cluttered outdoor traffic scene is also illustrated and assessed.

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A new formulation of a pose refinement technique using ``active'' models is described. An error term derived from the detection of image derivatives close to an initial object hypothesis is linearised and solved by least squares. The method is particularly well suited to problems involving external geometrical constraints (such as the ground-plane constraint). We show that the method is able to recover both the pose of a rigid model, and the structure of a deformable model. We report an initial assessment of the performance and cost of pose and structure recovery using the active model in comparison with our previously reported ``passive'' model-based techniques in the context of traffic surveillance. The new method is more stable, and requires fewer iterations, especially when the number of free parameters increases, but shows somewhat poorer convergence.