36,840 research outputs found

    Interaction and imitation in a world of Quixotes and Sanchos

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    Producción CientíficaThis paper studies a two-population evolutionary game in a new setting in between a symmetric and an asymmetric evolutionary model. It distinguishes two types of agents: Sanchos, whose payoffs are defined by a prisoner’s dilemma game, and Quixotes, whose payoffs are defined by a snowdrift game. Considering an imitative revision protocol, a revising agent is paired with someone from his own population or the other population. When matched, they observe payoffs, but not identities. Thus, agents in one population interact and imitate agents from their own population and from the other population. In this setting we prove that a unique mixed-strategy asymptotically stable fixed point of the evolutionary dynamics exists. Taking as an example the compliance with social norms, and depending on the parameters, two type of equilibrium are possible, one with full compliance among Quixotes and partial compliance among Sanchos, or another with partial compliance among Quixotes and defection among Sanchos. In the former type, Sanchos comply above their Nash equilibrium (as they imitate compliant Quixotes). In the latter type, Quixotes comply below their Nash equilibrium (as they imitate defecting Sanchos)

    Risk analysis of LPG tanks at the wildland-urban interface

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    In areas of wildland-urban interface (WUI), especially residential developments, it is very common to see liquefied petroleum gas (LPG) tanks, particularly with a higher ratio of propane, in surface installations serving homes. The most common tanks are between 1 and 5 m3 of capacity, but smaller ones of less than 1 m3 are more frequent. In case of accident, installations may be subject to fires and explosions, especially in those circumstances where legal and normative requirements allow very close exposure to flames from vegetable fuel near LPG tanks. In this project, it is intended to do a comprehensive diagnosis of the problem, addressing the compilation of information on real risk scenarios in historical fires. First, a preliminary presentation of the properties and characteristics of liquefied petroleum gas will be exposed. Its physical and chemical properties, production methodology, pressure and temperature diagrams and important considerations will be defined when using this type of substances in a storage tank of a certain volume. Next, a review of the situation of the existence of LPG tanks in the urban forest interfaces will be exposed. In this case, the main accidents caused by problems with the storage of LPG will be analyzed taking into account the relevance of BLEVE events in this type of incidents. To do this, the main scenarios that could take place in the event of a fire will be presented. Next, the existing legislation on the storage of LPG in these environments in some Mediterranean countries will be studied. In order to develop a comprehensive analysis, the main safety measures and distances will be considered, as well as the awareness of the possibility of vegetation material in the vicinity of LPG storage tanks, which is the main problem that will arise in a possible BLEVE scenario in case of fire. To finalize and facilitate understanding, a comparative table will be included with the aim of visualizing the main advantages and legislative deficiencies between the different countries. Following, the state of the art in terms of modelling LPG accidents at the WUI will be reviewed. Trying to simulate and predict this type of scenarios, it will see the models normally chosen to obtain the tolerable values selected and the answers obtained in each case. Finally, several fire scenarios will be simulated by means of a CFD tool (FDS, Fire Dynamics Simulator). In these simulations, the wind velocity and the distance of the combustible vegetal mass to the tank will be controlled in a WUI fire in which there is a tank of fixed dimensions. The temperature and the heat flow in each of the scenarios will be obtained, and the differences among the location of the sensors and the characteristics of the scenario will be analyzed. As a conclusion, it has been observed that there is a great amount of variables that are not contemplated by the regulatory organisms and that the existing legislation does not guarantee the safety of the population in this type of environment. From the simulations results, variables as temperature should be studied for further characterizations

    Algorithms for MIMO-OFDM wireless communications

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    Communications Group of University Carlos III of Madrid has designed and implemented algorithms for the improvement of the performance of MIMO-OFDM systems. This technology is capable of providing high data rate wireless communications. The developed algorithms allow, on one side, the correction of the imperfections introduced by radio-frequency equipment and, on the other side, adaptation of the transmission to the channel characteristics

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    Proceso por aceptación de decreto: el nuevo monitorio penal

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    En el presente artículo vamos a analizar una de las importantes reformas introducidas por la nueva Ley 41/2015, de 5 de octubre, de modificación de la Ley de Enjuiciamiento Criminal para la agilización de la justicia penal y el fortalecimiento de las garantías procesales, la incorporación del denominado 'proceso por aceptación de decreto' que reúne las características propias de un proceso monitorio, pero ahora en el orden penal

    Higgs bundles, abelian gerbes and cameral data

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    We study the Hitchin map for GRG_{\mathbb{R}}-Higgs bundles on a smooth curve, where GRG_{\mathbb{R}} is a quasi-split real form of a complex reductive algebraic group GG. By looking at the moduli stack of regular GRG_{\mathbb{R}}-Higgs bundles, we prove it induces a banded gerbe structure on a slightly larger stack, whose band is given by sheaves of tori. This characterization yields a cocyclic description of the fibres of the corresponding Hitchin map by means of cameral data. According to this, fibres of the Hitchin map are categories of principal torus bundles on the cameral cover. The corresponding points inside the stack of GG-Higgs bundles are contained in the substack of points fixed by an involution induced by the Cartan involution of GRG_{\mathbb{R}}. We determine this substack of fixed points and prove that stable points are in correspondence with stable GRG_{\mathbb{R}}-Higgs bundles.Comment: 34 page

    Characterization and evolution of the sediments of a Mediterranean coastal lagoon located next to a former mining area

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    Coastal lagoons are ecosystems that are relatively enclosed water bodies under the influence of both the terrestrial and themarine environment, being vulnerable to human impacts. Human activities, such asmining extraction, are significant anthropogenic coastal stressors that can negatively affect ecosystems and communities. In light of the above, the objective of this research is to examine the influence ofmetal mining activities on the composition of sediments of a Mediterranean coastal lagoon, named Mar Menor. This paper presents a comprehensive characterization for grain size, mineralogy, geochemistry and organic matter of sediments of this coastal lagoon, investigating their variation along space and time. Sedimentation dynamics are ruling clearly the grain size predominant in each area of the MarMenor coastal lagoon, determining the existence of entrainment, transport and sedimentation areas. Forminerals, elements and organic matter, sedimentation dynamics are also determining their distribution.The authors would like to thank Fundación Séneca for funding the project 12038/PI/09. In addition, they want to acknowledge the cooperation of J.M. Peñas, R. Baños, J. Saura, M. Saura and B. Villaescusa who helped us to improve this research and to Mr. and Mrs. Purves for their English grammar supervision

    Compliance with Social Norms as an Evolutionary Stable Equilibrium

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    Producción CientíficaThis paper studies a two-population evolutionary game in a new setting in between a symmetric and an asymmetric evolutionary model. It distinguishes two types of agents: Sanchos, whose payoffs are defined by a prisoner’s dilemma game, and Quixotes, whose payoffs are defined by a snowdrift game. Considering an imita- tive revision protocol, a revising agent is paired with someone from his own popula- tion or the other population. When matched, they observe payoffs, but not identities. Thus, agents in one population interact and imitate agents from their own population and from the other population. In this setting we prove that a unique mixed-strategy asymptotically stable fixed point of the evolutionary dynamics exists. Taking as an example the compliance with social norms, and depending on the parameters, two type of equilibrium are possible, one with full compliance among Quixotes and par- tial compliance among Sanchos, or another with partial compliance among Quixotes and defection among Sanchos. In the former type, Sanchos comply above their Nash equilibrium (as they imitate compliant Quixotes). In the latter type, Quixotes comply below their Nash equilibrium (as they imitate defecting Sanchos).This study was funded by the Spanish Government (projects ECO2014- 52343-P and ECO2017-82227-P), as well as financial aid from Junta de Castilla y León (projects VA024P17 and VA105G18), co-financed by FEDER funds
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