Asymptotic behaviour of a class of inhomogeneous scalar field cosmologies

The asymptotic behaviour of a class of inhomogeneous scalar field cosmologies with a Liouville type of potential is studied. We define a set of new variables for which the phase space of the system of Einstein equations is bounded. This allows us to perform a complete analysis of the evolution of these cosmologies. We also discuss the extension of the cosmic no-hair theorem.Comment: 23 pages, latex, 3 figures, to appear in J. Math. Phys., figures also available tarred and gzip'ed at http://tp.lc.ehu.es/figures.g

Enfermedad de Charcot-Marie-Tooth en Pediatría. Eficacia del tratamiento físico

Fundamento: La enfermedad de Charcot-Marie-Tooth o neuropatía hereditaria sensitivo-motora, es la neuropatía hereditaria primaria más frecuente, con una prevalencia de 1 por cada 2500 habitantes. La determinan mutaciones específicas de uno o varios genes relacionados con la estructura y formación de axones y vaina de mielina. El diagnostico se confirma mediante genética o diagnóstico molecular. Clínicamente se inicia en la infancia, comenzando con alteraciones motoras en las extremidades inferiores y deformidades como pie cavo, dedos en martillo y pie caído. El Tratamiento físico se centra en estiramientos de la fascia plantar, ejercicios de fortalecimiento, preservar el rango y la amplitud de movimiento y entrenar el equilibrio y la propiocepción para mantener la movilidad. Objetivos: La variabilidad en la utilización de medios físicos en el tratamiento de esta enfermedad exige estar actualizado y examinar los medios actuales para verificar la eficacia y seguridad de los medios físicos y para prestar una terapia física válida y eficiente. Método: Con el fin de realizar un revisión bibliográfica, crítica, actualizada y de calidad se ha obtenido la información en las bases de datos de US National Library of Medicine (PubMed), Physiotherapy Evidence Database, Cochrane Library y Clinical Key. Resultados: El entrenamiento de resistencia progresiva, de fuerza, los ejercicios aeróbicos y estiramientos son los tratamientos físicos habitualmente administrados a estos pacientes. La terapia física domiciliaria mantiene los resultados obtenidos con el tratamiento hospitalario supervisado. Conclusiones: El entrenamiento, ejercicio aeróbico y el estiramiento han demostrado su eficacia y seguridad. El tratamiento físico debe aplicarse prioritariamente para mejorar la fuerza muscular, realizar las actividades de la vida diaria y retrasar la progresión de la enfermedad.Grado en Fisioterapi

Unified Evaluation Framework for Stochastic Algorithms Applied to Remaining Useful Life Prognosis Problems

A unified evaluation framework for stochastic tools is developed in this paper. Firstly, we provide a set of already existing quantitative and qualitative metrics that rate the relevant aspects of the performance of a stochastic prognosis algorithm. Secondly, we provide innovative guidelines to detect and minimize the effect of side aspects that interact on the algorithms’ performance. Those aspects are related with the input uncertainty (the uncertainty on the data and the prior knowledge), the parametrization method and the uncertainty propagation method. The proposed evaluation framework is contextualized on a Lithium-ion battery Remaining Useful Life prognosis problem. As an example, a Particle Filter is evaluated. On this example, two different data sets taken from NCA aged batteries and two semi-empirical aging models available in the literature fed up the Particle Filter under evaluation. The obtained results show that the proposed framework gives enough details to take decisions about the viability of the chosen algorithm

Application Dependent End-of-Life Threshold Definition Methodology for Batteries in Electric Vehicles

The end-of-life event of the battery system of an electric vehicle is defined by a fixed end-oflife threshold value. However, this kind of end-of-life threshold does not capture the application and battery characteristics and, consequently, it has a low accuracy in describing the real end-of-life event. This paper proposes a systematic methodology to determine the end-of-life threshold that describes accurately the end-of-life event. The proposed methodology can be divided into three phases. In the first phase, the health indicators that represent the aging behavior of the battery are defined. In the second phase, the application specifications and battery characteristics are evaluated to generate the end-of-life criteria. Finally, in the third phase, the simulation environment used to calculate the end-of-life threshold is designed. In this third phase, the electric-thermal behavior of the battery at different aging conditions is simulated using an electro-thermal equivalent circuit model. The proposed methodology is applied to a high-energy electric vehicle application and to a high-power electric vehicle application. The stated hypotheses and the calculated end-of-life threshold of the high-energy application are empirically validated. The study shows that commonly assumed 80 or 70% EOL thresholds could lead to mayor under or over lifespan estimations

Schwarzschild Black Branes and Strings in higher-dimensional Brane Worlds

We consider branes embedded in spacetimes of codimension 1 and 2, with a warped metric tensor for the subspace parallel to the brane. We study a variety of brane-world solutions arising by introducing a Schwarzschild-like black hole metric on the brane and we investigate the properties of the corresponding higher-dimensional spacetime. We demonstrate that normalizable bulk modes lead to a vanishing flow of energy through the naked singularities. From this point of view, these singularities are harmless. (28 refs)

Gravitating global defects: the gravitational field and compactification

We give a prescription to add the gravitational field of a global topological defect to a solution of Einstein's equations in an arbitrary number of dimensions. We only demand that the original solution has a O(n) invariance with n greater or equal 3. We will see that the general effect of a global defect is to introduce a deficit solid angle. We also show how the same kind of scalar field configurations can be used for spontaneous compactification of "n" extra dimensions on an n-sphere.Comment: Uses revte

A Data-Driven Health Assessment Method for Electromechanical Actuation Systems

The design of health assessment applications for the electromechanical actuation system of the aircraft is a challenging task. Physics-of-failure models involve non-linear complex equations which are further complicated at the system-level. Data-driven techniques require run-to-failure tests to predict the remaining useful life. However, components are not allowed to run until failure in the aerospace engineering arena. Besides, when adding new monitoring elements for an improved health assessment, the airliner sets constraints due to the increased cost and weight. In this context, the health assessment of the electromechanical actuation system is a challenging task. In this paper we propose a data-driven approach which estimates the health state of the system without runto-failure data and limited health information. The approach combines basic reliability theory with Bayesian concepts and obtained results show the feasibility of the technique for asset health assessment

Gerra Hotza Espainiako "ABC" egunkariaren ikuspuntutik. Bost gertakariren inguruko gogoeta.

43 p. -- Bibliogr.: p. 28-43[EUS] Idazlan honen helburua Gerra Hotzaren eta honekiko espainiar prentsak duen ikuspuntuaren arteko konparaketa bat egitea da. Horretarako, lana hiru zatietan dago banatua, alde batetik, Gerra Hotzeko gertakari zehatz batzuen analisi historikoa, bestetik, prentsaren beraren garrantzia eta Gerra Hotzaren testuinguruko espainiako ibilbide historikoa eta, azkenik, lehen zatian hautatutako gertakarien eta prentsaren narrazioaren arteko alderaketa.[EN] The intention of this paper is to make a comparison between the events of the Cold War and its perspective on the Spanish press. For this purpose, the paper is divided into three sections, on the one hand, an historical analysis of the Cold War, on the other hand, the importance of the press and the historical trajectory of the Spanish press within the Cold War period and, finally, the comparison between the events chosen in the first section and the narration that the press makes of them