The generalised Gauss-Bonnet-Chern theorem as an instance in the theory of characteristic classes

Treballs Finals de Grau de Matemàtiques, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2021, Director: Ignasi Mundet i Riera[en] The Gauss-Bonnet theorem is one of the earliest classical results in differential geometry. It provides a link between the topology and the geometry of a smooth surface (that is, a smooth 2-manifold). A well-known, highly non-trivial generalisation of this to arbitrary (finite) dimension exists, which was first proven intrinsically (in other words, without recourse to the existence of an embedding of the manifold into an Euclidean space) by Shiing-Shen Chern in 1944. The aim of this work is to provide a full proof of a slightly more general result, which is valid for arbitrary vector bundles over a differential manifold, that gives as a direct corollary the Gauss-Bonnet-Chern theorem when considering the tangent bundle

A refinement of the Strichartz inequality with applications to the linear and nonlinear wave equations

Tesis doctoral inédita, leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Matemáticas. Fecha de lectura: 18-06-201

Violencia de género y masculinidad en Chile: una revisión de las políticas públicas en Democracia (1990-2014)

El artículo analiza la evolución de las políticas públicas implementadas en democracia (1990-2014) en materia de violencia machista e intervención con población masculina. Por una parte, interpreta desde la perspectiva de género, los mensajes y acciones a la hora de incluir a los hombres como parte de la solución del problema y de qué manera éstos reforzaron o no modelos masculinos sexistas y desigualitarios. Por otra, identifica y describe cómo la principal institución encargada de garantizar la protección de los derechos fundamentales de las mujeres (Servicio Nacional de la Mujer, SERNAM) abordó la problemática, a través del análisis de sus propuestas y orden de prioridades, así como las dificultades que se fueron presentando

Las mujeres en la izquierda chilena durante la Unidad Popular y la dictadura militar (1970-1990)

Tesis doctoral inédita, leída en la Universidad Autónoma de Madrid, Facultad de Filosofía y Letras, Departamento de Historia Contemporánea. Fecha de lectura: 19 de Septiembre del 201

Diferències sexuals i d'edat: una comparació de la leptina sèrica, els components de l'insulin-like growth factor-I i les concentracions de la globulina d'unió a hormones sexuals en una població sana

La secreció de la leptina està influenciada per factors diversos. L'eix GH/IGF-I té un paper important en la composició de l'organisme. La proteïna transportadora de les hormones sexuals (SHBG) és una glicoproteïna sintetitzada en el fetge i és la moduladora principal de la senyalització dels andrògens. En el present estudi hem investigat les diferències relacionades amb el sexe i l'edat en els nivells de leptina, del sistema IGF-I i de la SHBG en un grup d'adults sans seleccionats a l'atzar. L'estudi inclou 268 subjectes, representatius de tota la població de la ciutat de l'Hospitalet de Llobregat, distribuïts per sexe i edat, és a dir, 134 homes de 41,4 anys d'edat mitjana i 134 dones de 40,7 anys d'edat mitjana, amb rangs de 15-70 anys. Les concentracions de leptina es varen determinar per radioimmunoassaig (RIA), les concentracions totals d'IGF-I per assaig immunoradiomètric després d'extracció d'àcid-etanol, mentre que les d'IGF-I sèric lliure es van analitzar amb un assaig enzimoimmunomètric. Els nivells de la proteïna 3 transportadora de l'IGF (IGFBP3) foren determinats també amb RIA, mentre que els de SHBG per fluoroimmunoassaig. En els homes, la leptina va presentar un augment en la quarta dècada de la vida, mentre que l'IGF-I total, el lliure i la IGFBP3 disminuïen i les concentracions de SHBG augmentaven en les dècades quarta i sisena. En les dones, les concentracions de leptina augmentaven en les últimes dècades estudiades i les d'IGF-I total, lliure i IGFBP3 disminuïen en cada dècada estudiada. Les concentracions de SHBG disminuïen també en la darrera dècada. Les concentracions de leptina eren més baixes en els homes al comparar-los amb les dones en totes les edats estudiades (p = 0,001). Les concentracions d'IGF-I eren més baixes en els homes en totes les dècades estudiades (p = 0,01), exceptuant en les dues darreres. Les concentracions d'IGF-I lliure i d'IGFBP3 eren similars en els homes i en les dones de totes les edats (p = 0,09 i p = 0,2, respectivament). Les concentracions de SHBG eren més baixes en els homes que en les dones (p = 0,001) a excepció de la darrera dècada. Com a conclusió, podem assenyalar que en la present mostra de població, hem pogut demostrar un dimorfisme sexual en els nivells sèrics de leptina, d'IGF-I total i d'SHBG al llarg de totes les dècades estudiades.Leptin secretion is influenced by many factors, and the GH/IGF axis plays an important role in the regulation of body composition. Sex-hormone binding globulin (SHBG) is a glycoprotein synthesized in the liver, and it is a transport protein, which is a primary modulator of the androgen signal. In this cross-sectional study, we investigated sex and age differences as they corresponded to the concentration levels in leptin, the IGF-I system components, and SHBG, basing our study on data froma group of randomly selected, healthy adults. The study included 268 subjects, representative of the entire population of the city of L´Hospitalet de Llobregat in Spain. The distribution in sex and age were as follows: 134 males, with a mean age of 41.4 years, and 134 females, with a mean age of 40.7 years; Ages ranged from 15-70 years. Serumleptin concentrations were determined using radioimmunoassay (RIA); serum total IGF-I concentrations were obtained by immunoradiometric assay after acid-ethanol extraction, and serum free IGFI concentrations were obtained by enzymoimmunometric assay. Serum IGFBP3 concentrations were acquired using RIA and SHBG by fluoroimmunoassay. In the male population, leptin showed an increase in the 4th decade, a total IGF-I, free IGF-I, and IGFBP3 decrease throughout all of the decades, and an increase of SHBG in the 4th and 6th decades. In the female population, leptin concentrations increased in the later decades; total IGF-I, free IGF-I, and IGFBP3 levels decreased by decade, and SHBG concentrations decreased in the final decade. Leptin concentrations were lower in men than in women in all of the decades (p = 0.001). IGF-I concentrations were lower in men in all of the decades (p = 0.01), except in the last two, and free IGF-I and IGFBP3 concentrations were similar in men and women in all of the decades (p = 0.09 and p = 0.2, respectively). SHBG concentrations were lower in men than in women (p = 0.001), except in the final decade. In this well-characterized, randomly selected population of controls, we showed sexual dimorphism in leptin, total IGF-I, and SHBG concentrations with differences observable throughout the decades

Investigations into Lamarckism, Baldwinism and Local Search in Grammatical Evolution Guided by Reinforcement

Grammatical Evolution Guided by Reinforcement is an extension of Grammatical Evolution that tries to improve the evolutionary process adding break a learning process for all the individuals in the population. With this aim, each individual is given a chance to learn through a reinforcement learning mechanism during its lifetime. The learning process is completed with a Lamarckian mechanism in which an original genotype is replaced by the best learnt genotype for the individual. In a way, Grammatical Evolution Guided by Reinforcement shares an important feature with other hybrid algorithms, i.e. global search in the evolutionary process combined with local search in the learning process. In this paper the role of the Lamarck Hypothesis is reviewed and a solution inspired only in the Baldwin effect is included as well. Besides, different techniques about the trade-off between exploitation and exploration in the reinforcement learning step followed by Grammatical Evolution Guided by Reinforcement are studied. In order to evaluate the results, the system is applied on two different domains: a simple autonomous navigation problem in a simulated Kephera robot and a typical Boolean function problem

Fusion of probabilistic knowledge-based classification rules and learning automata for automatic recognition of digital images

In this paper, the fusion of probabilistic knowledge-based classification rules and learning automata theory is proposed and as a result we present a set of probabilistic classification rules with self-learning capability. The probabilities of the classification rules change dynamically guided by a supervised reinforcement process aimed at obtaining an optimum classification accuracy. This novel classifier is applied to the automatic recognition of digital images corresponding to visual landmarks for the autonomous navigation of an unmanned aerial vehicle (UAV) developed by the authors. The classification accuracy of the proposed classifier and its comparison with well-established pattern recognition methods is finally reported

Response threshold models and stochastic learning automata for self-coordination of heterogeneous multi-task distribution in multi-robot systems.

This paper focuses on the general problem of coordinating multiple robots. More specifically, it addresses the self-selection of heterogeneous specialized tasks by autonomous robots. In this paper we focus on a specifically distributed or decentralized approach as we are particularly interested in a decentralized solution where the robots themselves autonomously and in an individual manner, are responsible for selecting a particular task so that all the existing tasks are optimally distributed and executed. In this regard, we have established an experimental scenario to solve the corresponding multi-task distribution problem and we propose a solution using two different approaches by applying Response Threshold Models as well as Learning Automata-based probabilistic algorithms. We have evaluated the robustness of the algorithms, perturbing the number of pending loads to simulate the robot’s error in estimating the real number of pending tasks and also the dynamic generation of loads through time. The paper ends with a critical discussion of experimental results

Application of self-organizing techniques for the distribution of heterogeneous multi-tasks in multi-robot systems

This paper focuses on the general problem of coordinating of multi-robot systems, more specifically, it addresses the self-election of heterogeneous and specialized tasks by autonomous robots. In this regard, it has proposed experimenting with two different techniques based chiefly on selforganization and emergence biologically inspired, by applying response threshold models as well as ant colony optimization. Under this approach it can speak of multi-tasks selection instead of multi-tasks allocation, that means, as the agents or robots select the tasks instead of being assigned a task by a central controller. The key element in these algorithms is the estimation of the stimuli and the adaptive update of the thresholds. This means that each robot performs this estimate locally depending on the load or the number of pending tasks to be performed. It has evaluated the robustness of the algorithms, perturbing the number of pending loads to simulate the robot’s error in estimating the real number of pending tasks and also the dynamic generation of loads through time. The paper ends with a critical discussion of experimental results

A vision based aerial rbot solution for the IARC 2014 by the Technical University of Madrid

The IARC competitions aim at making the state of the art in UAV progress. The 2014 challenge deals mainly with GPS/Laser denied navigation, Robot-Robot interaction and Obstacle avoidance in the setting of a ground robot herding problem. We present in this paper a drone which will take part in this competition. The platform and hardware it is composed of and the software we designed are introduced. This software has three main components: the visual information acquisition, the mapping algorithm and the Aritificial Intelligence mission planner. A statement of the safety measures integrated in the drone and of our efforts to ensure field testing in conditions as close as possible to the challenge?s is also included