Finite size scaling of the bayesian perceptron

We study numerically the properties of the bayesian perceptron through a gradient descent on the optimal cost function. The theoretical distribution of stabilities is deduced. It predicts that the optimal generalizer lies close to the boundary of the space of (error-free) solutions. The numerical simulations are in good agreement with the theoretical distribution. The extrapolation of the generalization error to infinite input space size agrees with the theoretical results. Finite size corrections are negative and exhibit two different scaling regimes, depending on the training set size. The variance of the generalization error vanishes for $N \rightarrow \infty$ confirming the property of self-averaging.Comment: RevTeX, 7 pages, 7 figures, submitted to Phys. Rev.

Metodología para la elaboración de guías de intervención basadas en la evidencia en psicología y salud mental: procedimientos del NICE

El presente material explica el proceso de desarrollo de guías de práctica clínica que utiliza el NICE (National Institute for Health and Care Excellence), una de las instituciones de referencia en la elaboración de guías de intervenciones basadas en la evidencia. La primera parte está dirigida a la descripción de las característica generales de esta institución, que incluye la explicación de su organización y la estructuración en grupos de trabajo con perfiles y funciones bien definidas. Posteriormente se exponen los elementos claves de la metodología que utiliza el NICE para la elaboración de sus recomendaciones. Si bien en principio, estos procedimientos son generales y están fuertemente vinculados a las intervenciones en el ámbito sanitario, en los últimos años se han extendido al ámbito de las intervenciones sociales, educativas y de salud mental. Por lo cual, la metodología que aquí se expone, puede aplicarse para la generación de guías de intervención psicológica o psicoeducativas aplicables en distintos contextos

Influence of the Compaction Pressure and Sintering Temperature on the Mechanical Properties of Porous Titanium for Biomedical Applications

In the present work, the use of porous titanium is proposed as a solution to the difference in stiffness between the implant and bone tissue, avoiding the bone resorption. Conventional powder metallurgical technique is an industrially established route for fabrication of this type of material. The results are discussed in terms of the influence of compaction pressure and sintering temperature on the porosity (volumetric fraction, size, and morphology) and the quality of the sintering necks. A very good agreement between the predicted values obtained using a simple 2D finite element model, the experimental uniaxial compression behavior, and the analytical model proposed by Nielsen, has been found for both the Young’s modulus and the yield strength. The porous samples obtained by the loose sintering technique and using temperatures between 1000 °C −1100 °C (about 40% of total porosity) are recommended for achieving a suitable biomechanical behavior for cortical bone partial replacement.Ministry of Economy and Competitiveness of the State General Administration of Spain grant MAT2015-71284-

Estereotipos, tópicos y lenguaje de la programación sensacionalista en la televisión: programa «Corazón» de TVE

La televisión es considerada como un instrumento socializador, moderador de conciencias, y sobre todo, protagonista de la creación de la opinión crítica de la audiencia en programas relacionados con la vida social de las figuras más reconocidas en la actualidad sensacionalista. A raíz de la emisión de este tipo de programas suelen plantearse cuestiones como los efectos negativos al establecerse estereotipos y tópicos por el exceso de consumo de programas de crónica rosa y de dependencia del medio por parte la audiencia a no dejar de verlo. Existen pocos estudios realizados en cuanto a la recreación de mitos y estereotipos, así como el análisis del lenguaje de los programas relacionados con la crónica rosa. En este sentido, el Presente trabajo será el punto de partida de futuras propuestas para mejorar el consumo televisivo y así optimizar la creación de la percepción crítica de los telespectadores. A partir de los criterios y bases de estudio seleccionados, se pretende medir, usando una metodología cualitativa basada en la observación no participante y el análisis del discurso, con sus codificaciones previas, el programa «Corazón» de TVE con el objetivo de obtener resultados concretos que validen la repercusión mediática de este tipo de programas de prensa rosa, y a su vez el papel de los famosos y los informadores como protagonistas de la noticia. // Television is considered as a socializing instrument, ethical moderator and a prime mover of audience’s critical opinion, even though TV programs broadcasting focused on public life through tabloids, also known as pink press, have produced negative effects on stereotypes and topics due to excessive consumption of celebrity gossip and reliance of the spectators. There are a lack of researches about myths and stereotypes and language analysis related to pink press, therefore, this article is a starting point to future proposal that will improve the viewing consumption and audience’s critical perception. Based on a justified criteria and selected documents, this research evaluates a Television Program named «Corazón», broadcasted by TVE, through qualitative methodology based on non- participant observation and discourse analysis with its previous encodings for the purpose of obtaining several results that validate the media repercussion of this type of programs and also the role of journalists and celebrities as lead characters

Energy Storage Systems for Electric Vehicles: Performance Comparison based on a Simple Equivalent Circuit and Experimental Tests

The decision to select the most suitable type of energy storage system for an electric vehicle is always difficult, since many conditionings must be taken into account. Sometimes, this study can be made by means of complex mathematical models which represent the behavior of a battery, ultracapacitor or some other devices. However, these models are usually too dependent on parameters that are not easily available, which usually results in nonrealistic results. Besides, the more accurate the model, the more specific it needs to be, which becomes an issue when comparing systems of different nature. This paper proposes a practical methodology to compare different energy storage technologies. This is done by means of a linear approach of an equivalent circuit based on laboratory tests. Via these tests, the internal resistance and the self-discharge rate are evaluated, making it possible to compare different energy storage systems regardless their technology. Rather simple testing equipment is sufficient to give a comparative idea of the differences between each system, concerning issues such as efficiency, heating and self-discharge, when operating under a certain scenario. The proposed methodology is applied to four energy storage systems of different nature for the sake of illustration

Evaluation of the Magnetic Field Generated by the Inverter of an Electric Vehicle

In hybrid and electric vehicles, passengers sit very close to an electric system of significant power, which means that they may be subjected to high electromagnetic fields. The hazards of long-term exposure to these fields must be taken into account when designing electric vehicles and their components. Among all the electric devices present in the power train, the electronic converter is the most difficult to analyze, given that it works with different frequencies. In this paper, a methodology to evaluate the magnetic field created by a power electronics converter is proposed. After a brief overview of the recommendations of electromagnetic fields exposure, the magnetic field produced by an inverter is analyzed using finite element techniques. The results obtained are compared to laboratory measurements, taken from a real inverter, in order to validate the model. Finally, results are used to draw some conclusions regarding vehicle design criteria and magnetic shielding efficiency

Low-lying magnetic excitations of doubly-closed-shell nuclei and nucleon-nucleon effective interactions

We have studied the low lying magnetic spectra of 12C, 16O, 40Ca, 48Ca and 208Pb nuclei within the Random Phase Approximation (RPA) theory, finding that the description of low-lying magnetic states of doubly-closed-shell nuclei imposes severe constraints on the spin and tensor terms of the nucleon-nucleon effective interaction. We have first made an investigation by using four phenomenological effective interactions and we have obtained good agreement with the experimental magnetic spectra, and, to a lesser extent, with the electron scattering responses. Then we have made self-consistent RPA calculations to test the validity of the finite-range D1 Gogny interaction. For all the nuclei under study we have found that this interaction inverts the energies of all the magnetic states forming isospin doublets.Comment: 19 pages, 13 figures, 7 tables, accepted for publication in Phys. Rev.

Inverse sampling and triangular sequential designs to compare a small proportion with a reference value

Inverse sampling and formal sequential designs may prove useful in reducing the sample size in studies where a small population proportion p is compared with a hypothesized reference proportion p0. These methods are applied to the design of a cytogenetic study about chromosomal abnormalities in men with a daughter affected by Turner's syndrome. First it is shown how the calculated sample size for a classical design depends on the parameterization used. Later this sample size is compared with the required sample size in an inverse sampling design and a triangular sequential design using four different parameterizations (absolute differences, log-odds ratio, angular transform and Sprott's transform). The expected savings in sample size, when the alternative hypothesis is true, are 20% of the fixed sample size for the inverse sampling design and 40% for the triangular sequential design