Lovelock gravities from Born-Infeld gravity theory

We present a Born-Infeld gravity theory based on generalizations of Maxwell symmetries denoted as $\mathfrak{C}_{m}$. We analyze different configuration limits allowing to recover diverse Lovelock gravity actions in six dimensions. Further, the generalization to higher even dimensions is also considered.Comment: v3, 15 pages, two references added, published versio

How triathletes mount their bikes after first transition (T1). A proposal of classification

A proposal is submit for the classification referring to the different ways in which triathletes mount their bikes to start pedalling. This action happens at the end of the transition area (T1) after having gone across on foot, with the bikes at their side, or, led across by hand, in a specific way (Fernández, Romero, Merino and April, 2015). These are unique aspects of this sport, compared to other sports in which a bike is also used. The purpose of this research was concentrates in describing and classifying the motor behaviours that occur at the end of the transition area, in front of the “judge’s line”. This study was bassed on participants of 3 Spanish Elite Championships of different distances (407 triathletes). It was filmed in the moment when they picked up their bikes, passed through the transition area and mounted their bikes. Eleven different ways were discovered on how to mount a bike when passing the judge’s line.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Evaluación de la resistencia biaxial de paneles de fábrica de ladrillo reforzados exteriormente con fibra de carbono

Este estudio es la continuación de un estudio previo de otras dos tesinas que caracterizaron, tanto es comportamiento de la obra de fábrica, como el comportamiento de la misma después de sufrir un proceso de reparación. El objetivo de este trabajo es estudiar las posibilidades de aplicación de un refuerzo estructural, de materiales compuestos, aplicado a elementos de obra de fábrica. El paso previo es presentar el estado actual del conocimiento sobre la materia. A posteriori una presentación de los tipos de materiales utilizados para el estudio así como una pequeña caracterización de los mismos. El primer paso de este estudio es caracterizar el comportamiento del refuerzo con fibras de carbono mediante la construcción de unas probetas tipo para caracterizar los dos comportamientos extremos de la obra de fabrica, el trabajo a cortante puro y a compresión pura. A partir de estos resultados, se diseñan seis (6) métodos de refuerzo, sobre paneles de obra de fábrica de las mismas características que los trabajos anteriores. Para poder realizar una comparación realista de los resultados. Dichos refuerzo son diseñados para tratar de extraer la máxima información de los mismos, involucrando el mayor número de variables posible. Dichos paneles de obra de fábrica reforzados se ensayan a un estado de carga biaxial mediante la aplicación dos cargas, vertical y horizontal . El paso final del trabajo es dar la explicación de los resultados obtenidos, así como unas conclusiones de si es factible realizar un refuerzo con materiales compuestos, sobre un material de obra de fábrica, y sobre cual es el material más adecuado para ello

La mamografía como método de prevención secundaria en el cáncer de mama. Una revisión bibliográfica

El cáncer de mama supone un problema grave de salud debido a su gran incidencia cada año en las mujeres. Tanto es así que constituye la primera causa de muerte por tumores malignos en mujeres. Debido a esto, se implantó la mamografía como el mejor método para el cribado en los programas de prevención secundaria del cáncer de mama. Sin embargo, las opiniones difieren en cuanto a la relación beneficio/ riesgo ocasionada por ésta técnica. Es por ello que el objetivo principal de ésta revisión bibliográfica sea recopilar información sobre los beneficios y efectos indeseados producidos por el uso de la mamografía como método de prevención secundaria del cáncer de mama. Para realizar éste trabajo se ha realizado una revisión bibliográfica sistemática, haciendo uso de varias bases de datos como son las revistas médicas, las páginas oficiales e incluso los medios de comunicación. El análisis de los estudios muestra una gran disparidad de opiniones en cuanto a la mamografía como método eficaz para la detección precoz del cáncer de mama, llegando a no dejar clara su efectividad como consecuencia del creciente ascenso de falsos positivos, sobrediagnósticos y sobretratamientos. Finalmente se proponen nuevas líneas de investigación acerca del tema tratadoGrado en Enfermerí

Mixed Integer Linear Programming for Feature Selection in Support Vector Machine

This work focuses on support vector machine (SVM) with feature selection. A MILP formulation is proposed for the problem. The choice of suitable features to construct the separating hyperplanes has been modelled in this formulation by including a budget constraint that sets in advance a limit on the number of features to be used in the classification process. We propose both an exact and a heuristic procedure to solve this formulation in an efficient way. Finally, the validation of the model is done by checking it with some well-known data sets and comparing it with classical classification methods.Comment: 37 pages, 20 figure

Old ‘counter-revolution’, new ‘terrorism’ : historicizing the framing of violence in Xinjiang by the Chinese state

China has declared a war on terrorism in Xinjiang, identifying violence in the region as a top security threat. However, what nowadays is officially constructed as ‘terrorism’ was framed as ‘counter-revolution’ in the past. Informed by the concept of macrosecuritization and the agenda of critical terrorism studies, this article examines the changing nature of Chinese state framing of violence in Xinjiang. Through a comparative analysis of the discursive construction of the Baren (1990) and Maralbeshi (2013) violent incidents, I find that the terror lexicon has replaced old narratives of counter-revolution to legitimize a sustained crackdown under a novel geopolitical context. The construction of violence in Xinjiang as terrorism, I argue, is contingent, limited and unstable. It marginalizes factors other than an extremist or separatist agency in the incubation of the violence, in particular the frictions created by the crackdown with which the Chinese government is trying to placate the unrest

The stratified p-center problem

This work presents an extension of the p-center problem. In this new model, called Stratified p-Center Problem (SpCP), the demand is concentrated in a set of sites and the population of these sites is divided into different strata depending on the kind of service that they require. The aim is to locate p centers to cover the different types of services demanded minimizing the weighted average of the largest distances associated with each of the different strata. In addition, it is considered that more than one stratum can be present at each site. Different formulations, valid inequalities and preprocessings are developed and compared for this problem. An application of this model is presented in order to implement a heuristic approach based on the Sample Average Approximation method (SAA) for solving the probabilistic p-center problem in an efficient way.Comment: 32 pages, 1 pictur

The demand of business services in Spain

The growth in the outsourcing of services has become one of the most relevant features of the changes in manufacturing firms¿ behaviour. This paper provides empirical evidence about the extent and evolution of services outsourcing by Spanish manufacturing firms in 1990-1998. A general increase in outsourcing of services has been detected among firms in this period, although with strong differences across sectors and kind of services. Additionally, this paper studies the decision to outsource, devoting particular attention to the relationship between outsourcing and productivity. The results show the influence of variables such as firm size, ownership and location, among others