228 research outputs found

    Chaos in the one-dimensional wave equation

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    AbstractThis paper deals with the chaotic behavior of the solutions of a mixed problem for the one-dimensional wave equation with a quadratic boundary condition. This behavior is studied through the connection between the energy function and quadratic discrete dynamical systems

    Primera valoración genética para la disciplina de raid en el caballo de pura raza árabe español

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    El esquema de selección del caballo de Pura Raza Árabe fue aprobado por el Ministerio de Agricullura Pesca y Alimentación en septiembre de 2005. Dentro de él se especifica que se realizará una selección para mejorar los caracteres que potencien el alto rendimiento, que de forma natural, presenta la raza en la disciplina de raid. Se ha realizado la primera valoración genética para la disciplina de raid en el caballo de Pura Raza Árabe para lo cual se ha contado con datos de 249 caballos con un total de 547 participaciones en raids de diferentes categarías. La valoración genética se ha realizado para los caracteres puesto clasificatorio y tiempo de carrera. Previamente ha sido preciso realizar un estudio de los factores que afectan al rendimiento de esta disciplina. Los factores que se han incluido en el modelo de valoración por resultar estadísticamente significativos han sido el año de celebración de la prueba de raid, la zona geográfica donde se realiza la prueba y los kilómetros del recorrido. Además, se han incluido como covariables el número total de participantes en la prueba de raid para el carácter puesto clasificatorio y el tiempo medio de carrera para el carácter tiempo. las heredabilidades obtenidas presentan un valor bajo-medio (0,18 para el puesto clasificatorio y 0,13 para el tiempo). La evolución del valor genético para dichos caracteres nos muestra que el progreso genético ha sido escaso hasta el momento, pero la elevada variabilidad del carácter asegura un progreso genético adecuado si se realiza una apropiada intensidad de selección para dichos caracteres

    Random differential operational calculus: theory and applications

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    In this article, we obtain a product rule and a chain rule for mean square derivatives. An application of the chain rule to the mean square solution of random differential equations is shown. However, to achieve such mean square differentiation rules, fourth order properties were needed and, therefore, we first studied a mean fourth order differential and integral calculus. Results are applied to solve random linear variable coefficient differential problems

    Artificial recharge by means of careo channels versus natural aquifer recharge in a semi-arid, high-mountain watershed (Sierra Nevada, Spain)

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    This research was undertaken as part of the project "Impact, monitoring and assessment of global and climate change on water resources in high-mountain National Parks (CCPM) ", with reference number CANOA-51.3.00.43.00 and funded by Organismo Autonomo Parques Nacionales from the Ministerio para la Transicion Ecologica y el Reto Demografico. The authors thank the Ibero-American Science and Technology for Devel-opment Programme (CYTED) for its financial support to the network "Wa-ter Sowing and Harvesting in Protected Natural Areas" (419RT0577) . This work is a contribution to the Research Group RNM-126 of the Junta de Andalucia. Special thanks goes to the irrigation community in Berchules and the Sierra Nevada National Park for their collaboration. We also appre-ciate the support of AEMET and REDIAM, who provided meteorological and hydrological data. The authors would also like to thank the anonymous reviewers for their constructive comments and suggestions which led to a substantial improvement of the paper.The acequias de careo are ancestral water channels excavated during the early Al-Andalus period (8th–10th centuries), which are used to recharge aquifers in the watersheds of the Sierra Nevada mountain range (Southeastern Spain). The water channels are maintained by local communities, and their main function is collecting snowmelt, but also runoff from rainfall fromthe headwaters of river basins and distributing it throughout the upper parts of the slopes. Thismethod of aquifer artificial recharge extends the availability of water resources in the lowlands of the river basins during the dry season when there is almost no precipitation and water demand is higher. This study investigates the contribution of the careo channels in the watershed of Bérchules concerning the total aquifer recharge during the 2014–2015 hydrological year. Several channels were gauged, and the runoff data were compared with those obtained from a semi-distributed hydrological model applied to the same hydrological basin. The natural infiltration of meteoric waters accounted for 52%of the total recharge, while the remaining 48% corresponded to water transported and infiltrated by the careo channels. In other words, the careo recharge system enhances by 92% the natural recharge to the aquifer. Our results demonstrate the importance of this ancestral and efficient channel system for recharging slope aquifers developed in hard rocks. The acequias de careo are nature-based solutions for increasing water resources availability that have contributed to a prosperous life in the Sierra Nevada. Its long history (>1200 years) suggests that the system has remarkable resilience properties, which have allowed adaptation and permance for centuries in drastically changing climatic and socioeconomic conditions. This recharge system could also be applied to—or inspire similar adaptation measures in— semi-arid mountain areas around the world where it may help in mitigating climate change effects.Organismo Autonomo Parques Nacionales CANOA-51.3.00.43.00Ibero-American Science and Technology for Devel-opment Programme (CYTED) 419RT0577 RNM-126Junta de Andaluci

    Random differential operational calculus: Theory and applications

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    A product rule and a chain rule for mean square derivatives are obtained using fourth order properties. Applications to the mean square solution of random differential equations are shown

    Infinite Matrix Products and the Representation of the Matrix Gamma Function

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    We introduce infinite matrix products including some of their main properties and convergence results. We apply them in order to extend to the matrix scenario the definition of the scalar gamma function given by an infinite product due to Weierstrass. A limit representation of the matrix gamma function is also provided

    La afiliación a CC.OO.: evolución, estructura y trayectorias

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    Informe resultante de la investigación realizada por los autores en base a la explotación de la base de datos de afiliados/as al sindicato español mayoritario, analizando sus principales pautas y evolución temporal, distribución (territorial y sectorial), estructura organizativa y trayectorias

    Global Partial Density of States: Statistics and Localization Length in Quasi-one Dimensional disordered systems

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    We study the distributions functions for global partial density of states (GPDOS) in quasi-one-dimensional (Q1D) disordered wires as a function of disorder parameter from metal to insulator. We consider two different models for disordered Q1D wire: a set of two dimensional δ\delta potentials with an arbitrary signs and strengths placed randomly, and a tight-binding Hamiltonian with several modes and on-site disorder. The Green functions (GF) for two models were calculated analytically and it was shown that the poles of GF can be presented as determinant of the rank N×NN\times N, where NN is the number of scatters. We show that the variances of partial GPDOS in the metal to insulator crossover regime are crossing. The critical value of disorder wcw_c where we have crossover can be used for calculation a localization length in Q1D systems.Comment: RevTex4 8 .eps figure

    Solving random mixed heat problems: A random integral transform approach

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    [EN] This paper develops a random mean square Fourier transform approach to solve random partial differential heat problems with nonhomogeneous boundary value conditions. Random mean square operational rules for the random Fourier sine and cosine transforms are stated and illustrative examples are included.This work has been partially supported by the Spanish Ministerio de Economia y Competitividad grant MTM2013-41765-P.Casabán, MC.; Cortés, JC.; Jódar Sánchez, LA. (2016). Solving random mixed heat problems: A random integral transform approach. Journal of Computational and Applied Mathematics. 291:5-19. https://doi.org/10.1016/j.cam.2014.09.021S51929

    Computing option pricing models under transaction costs

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    AbstractThis paper deals with the Barles–Soner model arising in the hedging of portfolios for option pricing with transaction costs. This model is based on a correction volatility function Ψ solution of a nonlinear ordinary differential equation. In this paper we obtain relevant properties of the function Ψ which are crucial in the numerical analysis and computing of the underlying nonlinear Black–Scholes equation. Consistency and stability of the proposed numerical method are detailed and illustrative examples are given
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