1,621 research outputs found

    Gaussian rational quadrature formulas for ill-scaled integrands

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    AbstractA flexible treatment of Gaussian quadrature formulas based on rational functions is given to evaluate the integral ∫If(x)W(x)dx, when f is meromorphic in a neighborhood V of the interval I and W(x) is an ill-scaled weight function. Some numerical tests illustrate the power of this approach in comparison with Gautschi’s method

    Las plegarias en las vidas de santos de Gonzalo de Berceo

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    Analizamos en este artículo los diferentes tipos de plegaria incluidos por Gonzalo de Berceo en sus vidas de santos, como también sus funciones y significados según la peculiar estructura del relato hagiográfico. Concluimos que el predominio de plegarias humildes y frecuentes dedicadas a la adoración y la alabanza en las secciones iniciales de la historia, y el predominio de plegarias de petición consideradas como causas instrumentales para los milagros realizados por el santo en las secciones siguientes, postulan que la eficacia de la plegaria es una consecuencia de su plegaria y humildad. This article analyses the different types of prayers included by Gonzalo de Berceo in his lives of saints, as well as their funcitons and meanings according to the peculiar structure of he hagiographic narrative. The conclusión is that the preominance of Humble and frecuent prayers dedicated to adoration and praise in the inicial sections of the story, and the predominante of petition prayers considered as instrumental causes for the miracles done by the saint in the following sections, postulate that the efficacy of prayer is a consequence of its frequency and humility

    Design of a control with multiple inputs multiple outputs by decoupling

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    In industry, most processes can be modeled by a system of equations that can be monovariable or multivariable. In our case, we will present a multivariable system more adjusted to real cases and on which a control system is available. This article presents a decoupling control method for two inputs two outputs through a centralized multivariable controller using a decoupling network and a diagonal controller, this technical advantage allows reduction in computing time. It shows the methodology by which a multivariate system can be represented as the composition of different coupled systems in this way that the control of the variables involved in it can be done separately, facilitating the control system, this implies a modification in the outputs to be affected. In the same way, the two-inlet with 2-outlet distillation system was also studied. © Published under licence by IOP Publishing Ltd

    Naturally graded quasi-filiform Leibniz algebras

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    AbstractThe classification of naturally graded quasi-filiform Lie algebras is known; they have the characteristic sequence (n−2,1,1) where n is the dimension of the algebra. In the present paper we deal with naturally graded quasi-filiform non-Lie–Leibniz algebras which are described by the characteristic sequence C(L)=(n−2,1,1) or C(L)=(n−2,2). The first case has been studied in [Camacho, L.M., Gómez, J.R., González, A.J., Omirov, B.A., 2006. Naturally graded 2-filiform Leibniz Algebra and its applications, preprint, MA1-04-XI06] and now, we complete the classification of naturally graded quasi-filiform Leibniz algebras. For this purpose we use the software Mathematica (the program used is explained in the last section)

    Equivalence of two approaches for the inhomogeneous density in the canonical ensemble

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    In this article we show that the inhomogeneous density obtained from a density-functional theory of classical fluids in the canonical ensemble (CE), recently presented by White et al [Phys. Rev. Lett. 84 (2000) 1220], is equivalent to first order to the result of the series expansion of the CE inhomogeneous density introduced by Gonzalez et al [Phys. Rev. Lett. 79 (1997) 2466].Comment: 6 pages, RevTe

    Calibración con parámetros de los ítems fijos para la evaluación del funcionamiento diferencial del ítem en tests adaptativos informatizados

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    In computerized adaptive testing pretest items are presented in conjunction with operational items to renew the item bank. Pretest items are calibrated, and possible differential item functioning (DIF) is analyzed. Some difficulties arise due to the large amount of missing responses, which can be avoided by the use of fixed item parameter calibration (FIPC; Kim, 2006) methods. In this study, we applied the multiple weights updating and multiple EM cycles method, with response imputation (as suggested by Lei, Chen, & Yu, 2006) and without response imputation for non-applied items. The IRT likelihood ratio test (IRT-LRT) was used for DIF detection. The manipulated factors were type of DIF, DIF size, impact size, test length, and sample size. The results showed that the FIPC method is suitable for detecting large-size DIF in large samples. In the presence of impact the use of imputation led to a bias in the effect-size measure of the DIFEn tests adaptativos informatizados los ítems pretest se presentan junto con los ítems operativos para renovar el banco de ítems. Los ítems pretest se calibran y se analiza el posible funcionamiento diferencial de los ítems (FDI). Este análisis presenta algunos problemas debido a la gran cantidad de respuestas faltantes, una de las posibles soluciones es el uso de métodos de calibración con parámetros fijos (Kim, 2006). En este estudio, aplicamos el método de múltiples actualizaciones de los pesos y múltiples ciclos EM con imputación de respuestas (tal y como propusieron Lei, Chen, y Yu, 2006) y sin imputación de respuesta para los ítems no aplicados. Empleamos el test de razón de verosimilitudes de la TRI para la detección del FDI. Los factores manipulados fueron el tipo de FDI, el tamaño del FDI, el tamaño del impacto, la longitud del test, y el tamaño de las muestras. Los resultados señalan que el método de calibración con parámetros fijos es una alternativa adecuada para la detección de un FDI grande cuando se utilizaron muestras grandes. En presencia de impacto el uso de imputación de respuestas introdujo un sesgo en las medidas del tamaño del efecto del FDIThis research was partly supported by a grant from the Spanish Ministry of Education and Science [PSI2009-10341

    Clinical considerations on the posology of direct oral anticoagulants

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    Los anticoagulantes dicumarínicos han demostrado su eficacia en pacientes con fibrilación auricular no valvular. Sin embargo, presentan desventajas como la necesidad de ajustar la dosis y la interacción con fármacos y alimentos. Por su parte, los anticoagulantes orales de acción directa se presentan como una alternativa eficaz y segura con un manejo clínico menos complejo. Existe un considerable debate sobre los criterios de selección de las pautas posológicas de los anticoagulantes orales de acción directa. Las diferencias entre ellos y sus pautas de administración han despertado dudas sobre los criterios de selección clínicos, farmacocinéticos y farmacodinámicos que avalan dicha posología. Esta revisión analiza de forma crítica las evidencias disponibles y su impacto en la selección final del esquema posológic

    Depositional style and tectonostratigraphic evolution of the El Bierzo Tertiary Subbasin (Pyrenean orogen, NW Spain)

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    El Bierzo Tertiary sub-basin (Oligocene–Miocene, NW Spain) is a small remnant of the western Duero Basin, a nonmarine broken foreland basin developed in front of the Cantabrian Mountains (Pyrenean orogen). The alluvial infill of El Bierzo Tertiary sub-basin consists of a coarsening-upward succession from fluvial (Toral Formation) to alluvial-fan deposits (Las Médulas Formation) and reflects the uplift of the Cantabrian Mountains, in the north, and then of the related Galaico-Leoneses Mountains, in the south. These alluvial deposits show signs of having been laid down mainly by catastrophic flows (flood-dominated systems) and consist of three main depositional elements, namely, flood-plain fines, and lobe and channel conglomerates and sandstones. The vertical stacking patterns of these deposits and their relationships to the Alpine structures permit to unravel the tectonosedimentary evolution of the basin. The alluvial-plain element is the main constituent of a wide unconfined alluvial plain (Toral Formation) during the early stages of basin evolution, whereas the channel and lobe elements form a set of relatively small, laterally confined alluvial fans (Las Médulas Formation) fed first from the north and then from the south. Las Médulas deposits form two superposed units, the lower unit, cut by the Alpine thrusts, shows a progradational character, and the upper unit, which postdates most of the thrusts but not the youngest ones, displays a composite retrogradational trend. This organisation reflects the interplay between thrust emplacement and alluvial-fan sedimentation and suggests that maximum progradation took place during the climax of Alpine deformation
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