9,444 research outputs found

    Effect of van der Waals forces on the stacking of coronenes encapsulated in a single-wall carbon nanotube and many-body excitation spectrum

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    We investigate the geometry, stability, electronic structure and optical properties of C24H12 coronenes encapsulated in a single-wall (19,0) carbon nanotube. By an adequate combination of advanced electronic-structure techniques, involving weak and van derWaals interaction, as well as many-body effects for establishing electronic properties and excitations, we have accurately characterized this hybrid carbon nanostructure, which arises as a promising candidate for opto-electronic nanodevices. In particular, we show that the structure of the stacked coronenes inside the nanotube is characterized by a rotation of every coronene with respect to its neighbors through van derWaals interaction, which is of paramount importance in these systems. We also suggest a tentative modification of the system in order this particular rotation to be observed experimentally. A comparison between the calculated many-body excitation spectrum of the systems involved reveals a pronounced optical red-shift with respect to the coronene-stacking gas-phase. The origin of this red-shift is explained in terms of the confinement of the coronene molecules inside the nanotube, showing an excellent agreement with the available experimental evidence

    Memoria y ficción en El material humano de Rodrigo Rey Rosa: la representación imposible de la violencia en Guatemala

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    El presente artículo analiza la novela de Rodrigo Rey Rosa, El material humano (2009), y la representación de la violencia que propone en su investigación sobre la realidad histórica de Guatemala a lo largo del siglo xx. El protagonista inicia una labor de indagación sobre las causas de la violencia de su país, para intentar comprender el origen del conflicto. Sin embargo, esta labor terminará con un triple fracaso: el cognoscitivo, el expresivo y el deontológico, representativos de toda una serie de narraciones sobre la memoria histórica en América Latina y España.This paper analyzes Rodrigo Rosa’s novel El material humano (2009), especially its representation of violence as seen through the author’s research on Guatemalan 20th century History. In the novel, the main character searches into the causes of violence in his country, trying to understand the origin of the conflict. However, his work ends in a triple failure: a cognitive, an aesthetic and an ethical one. That failure, as this paper proposes, represents a whole series of stories about the tragedy of historical memory in Latin America and Spain

    Con fallas activas hay y habrá terremotos

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    El catastrófico terremoto ocurrido la madrugada del 23 de agosto en la región de Rieti, en Italia central, vuelve a impactarnos al poner de manifiesto el tremendo poder destructor de los sismos de magnitud mayor de 5 y poco profundos en el ámbito Mediterráneo, con unas poblaciones rurales con construcciones altamente vulnerables. Un evento como este puede repetirse en Italia o incluso en España, puesto que allí donde hay fallas activas de gran longitud, ha habido y habrá terremotos

    Non-centralized Control for Flow-based Distribution Networks: A Game-theoretical Insight

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    This paper solves a data-driven control problem for a flow-based distribution network with two objectives: a resource allocation and a fair distribution of costs. These objectives represent both cooperation and competition directions. It is proposed a solution that combines either a centralized or distributed cooperative game approach using the Shapley value to determine a proper partitioning of the system and a fair communication cost distribution. On the other hand, a decentralized noncooperative game approach computing the Nash equilibrium is used to achieve the control objective of the resource allocation under a non-complete information topology. Furthermore, an invariant-set property is presented and the closed-loop system stability is analyzed for the non cooperative game approach. Another contribution regarding the cooperative game approach is an alternative way to compute the Shapley value for the proposed specific characteristic function. Unlike the classical cooperative-games approach, which has a limited application due to the combinatorial explosion issues, the alternative method allows calculating the Shapley value in polynomial time and hence can be applied to large-scale problems.Generalitat de Catalunya FI 2014Ministerio de Ciencia y Educación DPI2016-76493-C3-3-RMinisterio de Ciencia y Educación DPI2008-05818Proyecto europeo FP7-ICT DYMASO

    Derechos de la persona o de la ciudadanía: los inmigrantes

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    Perplejidades sobre el estado del bienestar

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    Fracturación y control tectosedimentario neógeno en el borde sureste de la Cuenca de Lorca

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    En este trabajo se estudia el control tectosedimentario ejercido por la fracturación neógena en la sedimentación en el borde suroriental de la Cuenca de Larca. El control más importante está impuesto por la actividad del Corredor Tectónico de la Falla de Alhama de Murcia. Este corredor controló la formación del borde sur de la citada cuenca a través de movimientos de carácter normal que activaron el inicio del depósito mioceno. Durante el Tortoniense y el Messiniense la cinemática sinestral e inversa del corredor controla la formación del anticlinal que estructura la Sierra de La Tercia y provoca reactivaciones de procesos erosivos en áreas emergidas
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