4,769 research outputs found

    τ\tau-Flavour Violation at the LHC

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    We study the conditions required for χ2χ+τ±μ\chi_2 \to \chi + \tau^\pm \mu^\mp decays to yield observable tau flavour violation at the LHC, for cosmologically interesting values of the neutralino relic density. These condition can be achieved in the framework of a SU(5) model with a see-saw mechanism that allows a possible coexistence of a LHC signal a low prediction for radiative LFV decays.Comment: 7 pages, 5 figures, Prepared for the proceedings of the workshop: "LC09: e+ee^+ e^- Physics at the TeV Scale and the Dark Matter Connection", 21-24 September 2009, Perugia, Ital

    Incidencia de la dolarización sobre la economía ecuatoriana, 2000 - 2015

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    The goal of this paper is to analyze the impact of the official dollarization on the evolution of the main macroeconomic indicators in Ecuador since 2000 to 2015. To do this, a comparative analysis of the functioning of the Ecuadorian economy before and after the official dollarization is carried out. It is found that this new system that imposes monetary rigidity and clear limits to discretion, has caused a remarkable macroeconomic stability, sustained growth, recovery of income, and a reduction of poverty.Este artigo tem como objetivo analisar o impacto que a dolarização oficial teve na evolução dos principais indicadores macroeconômicos no Equador no período de 2000 a 2015. Para tanto, realiza-se uma análise comparativa do funcionamento da economia equatoriana antes e depois da dolarização oficial. Nota-se que esse novo sistema, visto que impõe rigidez monetária e limites claros à discricionariedade, gerou notável estabilidade macroeconômica, crescimento contínuo, recuperação dos ingressos e diminuição da pobreza.Este artículo tiene como objetivo analizar el impacto que la dolarización oficial ha tenido en la evolución de los principales indicadores macroeconómicos en Ecuador en el período 2000 - 2015. Para ello se realiza un análisis comparativo del funcionamiento de la economía ecuatoriana antes y después de la dolarización oficial. Se encuentra que este nuevo sistema, dado que impone rigidez monetaria y límites claros a la discrecionalidad, ha generado notable estabilidad macroeconómica, crecimiento sostenido, recuperación de los ingresos y disminución de la pobreza

    Volcanisme, tectonique et réseau hydrographique sur le piémont andin du désert du nord du Chili

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    À partir d'une photographie aérienne verticale, remarquable par les anomalies qu'elle fait apparaître dans le tracé du réseau hydrographique, on peut retracer les principales étapes de l'évolution du piémont andin dans le désert du Nord du Chili pendant le Cénozoïque supérieur : 1) puissante accumulation volcano-détritique au Miocène inférieur et moyen, conséquence du soulèvement des Andes à la fin de l'Oligocène; 2) glaciplanation au Miocène supérieur; 3) incision des cours d'eau, perturbée par des mouvements tectoniques importants au Pliocène; 4) changements climatiques, caractérisés par des atténuations passagères de l'aridité, à l'origine de différentes générations de dépôts détritiques au Pliocène et au Quaternaire.From a vertical aerial photograph, noteworthy for anomalies which characterize the hydrographic network of the depicted area, are deduced the main stages of the Andean piedmont evolution in the desert of northernmost Chile during the Upper Cenozoic: 1) as a consequence of the uplift of the Andes at the end of the Oligocène, thick accumulation of continental sediments and ignimbritic lava flows during the Lower and Middle Miocene; 2) development of a planation surface of pediment type in the Late Miocene; 3) channel incision, disturbed by important tectonic movements in the Pliocene; 4) climatic changes, marked by increased precipitation, generating several generations of clastic deposits in the Pliocene and the Quaternary.Una fotografia aérea vertical, notable por las anomalias que aparecen en Ia red hidrografica, permite aclarar las principales etapas de la evolucion del pedemonte andino del Norte Grande chileno durante el Cenozoico superior: 1) potente acumulacion volecanica y detritica en el Mioceno inferior y medio, como consecuencia del solevantamiento de los Andes a fines del Oligoceno; 2) pediplanacion en el Mioceno superior; 3) encajonamiento de los cursos de agua, perturbado por importantes movimientos tectônicos en el Plioceno; 4) cambios climaticos, caracterizados por una atenuacion de la aridez, que producen varias generaciones de depositos detriticos en el Plioceno y el Cuaternario

    Promotion to Innovation, Understanding and Transfer of Technology Through Hubs Projects Promoted by the National Secretariat of Higher Education

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    This article allows us to expose the promotion of innovation, entrepreneurship and technology transfer and the importance of a society demanding new things, as a result of which there is an increasingly demanding need for satisfaction for those who consume them and make the generation of new products, goods or services are mostly in demand. This research work aims to externalize the national situation of ecosystems of innovation, generation of knowledge and commercialization of the same for its use in the post of the development and consolidation of the HUB project. In this article, an exploratory research was carried out for the selection of relevant diagnostic information on these issues at the global and regional level, and a deductive study of situations already established to situations that are emerging in our country as novel fields of opportunity in difficult situations. There are disparities in the results of the HUBs at the national level, due to the difficulties that this project has generated in trying to adapt to their local realities, despite this, they have been able to generate operating regulations that support the efforts of this project and also the status regarding the activities in which each one is. Keywords: innovation, entrepreneurship, technology transfer, HUBS. Resumen Este artículo permite exponer el fomento a la innovación, el emprendimiento y la transferencia de tecnología y la importancia de una sociedad demandante de cosas nuevas, producto de ello se genera una necesidad de satisfacción cada vez más exigente de quienes las consumen y hacen que la generación de nuevos productos, bienes o servicios sean mayormente demandados. Este trabajo de investigación pretende exteriorizar la situación nacional de ecosistemas de innovación, generación de conocimiento y comercialización del mismo para su aprovechamiento en post del desarrollo y consolidación del proyecto HUB. En este artículo se realizó una investigación exploratoria para la selección de información relevante del diagnóstico de éstas temáticas a nivel mundial y regional, y un estudio deductivo de situaciones ya establecidas a situaciones que están surgiendo en nuestro país como campos novedosos de oportunidad en situaciones difíciles. Existen disparidad de resultados de los HUB´s a nivel nacional, debido a las dificultades que este proyecto ha generado al tratar de adaptarse a sus realidades locales, a pesar de ello, se han logrado generar una normativa de funcionamiento que de soporte a las gestiones de este proyecto y también el estado respecto de las actividades en las que se encuentran cada uno. Palabras clave: innovación, emprendimiento, transferencia de tecnología, HUBS

    Hyperelliptic Jacobians and isogenies

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    In this note we mainly consider abelian varieties isogenous to hyperelliptic Jacobians. In the first part we prove that a very general hyperelliptic Jacobian of genus is not isogenous to a non-hyperelliptic Jacobian. As a consequence we obtain that the intermediate Jacobian of a very general cubic threefold is not isogenous to a Jacobian. Another corollary tells that the Jacobian of a very general d-gonal curve of genus is not isogenous to a different Jacobian. In the second part we consider a closed subvariety of the moduli space of principally polarized varieties of dimension . We show that if a very general element of is dominated by the Jacobian of a curve C and , then C is not hyperelliptic. In particular, if the general element in is simple, its Kummer variety does not contain rational curves. Finally we show that a closed subvariety of dimension such that the Jacobian of a very general element of is dominated by a hyperelliptic Jacobian is contained either in the hyperelliptic or in the trigonal locus

    On the dimension of Voisin sets in the moduli space of abelian varieties

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    We study the subsets Vk(A)V_k(A) of a complex abelian variety AA consisting in the collection of points xAx\in A such that the zero-cycle {x}{0A}\{x\}-\{0_A\} is kk-nilpotent with respect to the Pontryagin product in the Chow group. These sets were introduced recently by Voisin and she showed that dimVk(A)k1\dim V_k(A) \leq k-1 and Vk(A)V_k(A) is countable for a very general abelian variety of dimension at least 2k12k-1. We study in particular the locus Vg,2\mathcal V_{g,2} in the moduli space of abelian varieties of dimension gg with a fixed polarization, where V2(A)V_2(A) is positive dimensional. We prove that an irreducible subvariety YVg,2\mathcal Y \subset \mathcal V_{g,2}, g3g\ge 3, such that for a very general yYy \in \mathcal Y there is a curve in V2(Ay)V_2(A_y) generating AA satisfies dimY2g1.\dim \mathcal Y \le 2g - 1. The hyperelliptic locus shows that this bound is sharp.Comment: Final version to appear in Mathematische Annale
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