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Search Results: 1 - 10 of 356737 matches for " Calderón G "
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"Esa hoja verde y divina la coca es"
Fernando Calderón G.
Historia Crítica , 1990,
Abstract:
Beurteilung der Güte qualitativer Gesundheitsforschung: Kriterien, Prozess, Schreiben Assessing the Quality of Qualitative Health Research: Criteria, Process and Writing Evaluación de la calidad de la investigación cualitativa en salud: criterios, proceso y escritura
Carlos Calderón Gómez
Forum : Qualitative Social Research , 2009,
Abstract: Die Frage der Beurteilung der Güte von qualitativer Forschung ist besonders virulent im Bereich qualitativer Gesundheitsforschung. Sowohl die dort implizierten theoretischen Entscheidungen als auch die praktische Nutzung der gewonnenen Ergebnisse verweisen auf die Notwendigkeit der Identifizierung geteilter Koordinaten der Qualit tsbeurteilung, die die methodologischen und gegenstandsbezogenen Erfordernisse im Kontext qualitativer Gesundheitsforschung angemessen berücksichtigen. Dieser Erfordernis folgend werden drei Dimensionen identifiziert, n mlich "Kriterien", "Prozess" und "Schreiben", die in bisher ver ffentlichten Vorschl gen zur Beurteilung der Güte qualitativer Gesundheitsforschung oft vermischt werden. Mit dem Ziel der Integration neuer Beitr ge ist ein breiter überblick verfügbarer Literatur Teil der Darstellung dieser Dimensionen und ihrer wechselseitigen Beziehungen. URN: urn:nbn:de:0114-fqs0902178 The debate surrounding the assessment of quality in qualitative research becomes particularly relevant in the field of Qualitative Health Research (QHR). The characteristics of both its theoretical implications and the practical use of its results support the need for defining shared coordinates for quality assessment that respond to both the methodological requirements and the substantive components of QHR. From this I considered identifying three dimensions: criteria, process and writing. These have frequently been intermingled in previously published QHR quality assessment proposals. Aiming at integrating the development of new and necessary contributions, my explanation of these dimensions and the relationships among them is based on a wide-ranging review of published literature. URN: urn:nbn:de:0114-fqs0902178 El debate sobre la evaluación de la calidad en las investigaciones cualitativas (IC) adquiere especial importancia en el ámbito de la Investigación Cualitativa en Salud (ICS). Las particularidades de sus repercusiones teóricas y de la aplicación práctica de sus resultados justifican la necesidad de avanzar en la delimitación de coordenadas compartidas para la evaluación de la calidad que respondan tanto a los requisitos metodológicos como a los componentes sustantivos propios de la ICS. En este sentido, se considera importante diferenciar tres dimensiones representadas por los criterios, el proceso y la escritura, que aparecen con frecuencia entremezcladas en las propuestas publicadas al respecto. En la explicación de dichas dimensiones y de sus interrelaciones se ha partido de una amplia revisión de las publicaciones previas, con una
Las vanguardias históricas en perspectiva
Jorge Calderón Gómez
Nómadas , 2005,
Abstract: El presente artículo analizará las características específicas de algunos Manifiestos vanguardistas con el fin de establecer, a partir de los materiales y contenidos hallados en estos programas, un análisis comparativo y crítico respecto a los elementos revolucionarios establecidos por Marx y Engels en el "Manifiesto comunista" de 1848. Por otro lado la investigación acerca de los movimientos de vanguardia tomará como base interpretativa la obra de Eduardo Subirats, en concreto tres de sus textos: 1). El final de las vanguardias; 2). La cultura del espectáculo; 3). La linterna mágica. Las aproximaciones de este autor resaltan el carácter ambiguo del proyecto de las vanguardias, así como las estrechas relaciones que guardan estos movimientos artísticos con el proceso de modernización, en cuanto extensión globalizada de una racionalidad instrumental, sustentada en criterios economicistas y productivos. Se trata pues de relacionar la modernidad estética de las vanguardias con la modernidad en cuanto proceso histórico general. Acentuando en uno y otro caso el problema de lo moderno como "Ilustración insatisfecha". Las distintas reflexiones elaboradas estarán atravesadas por las intuiciones y propuestas del crítico cultural Carlos Jiménez, a partir de la conferencia dada en el curso "Marxupdate" de la UCM, donde se definio al arte actual como arte trans-vanguardista, en cuanto arte normalizado, integrado a la lógica del capitalismo tardío, y donde se analiza el texto mencionado de Marx-Engels como portador de muchas de las propuestas recogidas posteriormente por los movimientos artísticos de vanguardia.
Sala de maquinas: aproximación al pensamiento de Gilles Deleuze y Félix Guattari
Jorge Calderón Gómez
Nómadas , 2006,
Abstract: En el presente artículo vamos a reflexionar sobre la cuestión del "maquinismo" en la filosofía de Gilles Deleuze y Félix Guattari, tarea que llevaremos a cabo en dos fases o momentos distintos. En primer lugar revisaremos los aspectos ontológicos generales de la noción de "máquina" a partir del texto "La heterogénesis maquínica", recopilado en el trabajo "Caosmosis" (Chaomose, 1992), profundizando en los distintos aspectos que posibilitan la ampliación del concepto de máquina más allá de los límites que representan los dispositivos tecnológicos. Y en segundo lugar vamos a estudiar los diversos puntos de contacto (interfaz) que enlazan el modelo ontológico del "esquizoanálisis" con la imagen del "deseo" y la teoría del inconsciente que ambos autores elaboran en torno a las categorías de: {"máquina deseante" & "producción deseante"}; en este caso seguiremos el hilo argumentativo del trabajo "Las máquinas deseantes", primera parte del "Anti-Edipo" (L′Anti-Oedipe. Capitalisme et schizophrénie, 1972).
Approximate Closed-Form Formulas for the Zeros of the Bessel Polynomials
Rafael G. Campos,Marisol L. Calderón
International Journal of Mathematics and Mathematical Sciences , 2012, DOI: 10.1155/2012/873078
Abstract: We find approximate expressions and for the real and imaginary parts of the th zero of the Bessel polynomial . To obtain these closed-form formulas we use the fact that the points of well-defined curves in the complex plane are limit points of the zeros of the normalized Bessel polynomials. Thus, these zeros are first computed numerically through an implementation of the electrostatic interpretation formulas and then, a fit to the real and imaginary parts as functions of , and is obtained. It is shown that the resulting complex number is -convergent to for fixed . 1. Introduction The polynomial solutions of the differential equation were studied systematically in [1] by the first time. They are named (generalized) Bessel polynomials and are given explicitly by as it can be shown in [2]. Here, is the Pochhammer symbol and . Many properties as well as applications are associated to this equation; the traveling waves in the radial direction which are solutions of the wave equation in spherical coordinates can be written in terms of the polynomial solutions of (1.1). Also, this equation has application in network and filter design, isotropic turbulence fields, and more (see the monograph [2] or [3–14] and references therein for some other results). Among these, several results about the important problem concerning the location of its zeros have been obtained [8–11] and in [12], explicit expressions for sum rules and for the homogeneous product sum symmetric functions of zeros of these polynomials are given. On the other hand, the electrostatic interpretation of these zeros as the equilibrium configuration in the complex plane with a logarithmic electric potential and a dipole at the origin has been given in [13], and in [14] it is shown that this equilibrium configuration is not stable. Thus, these cases show that it is desirable to acquire new analytical knowledge about the location of the zeros of the Bessel polynomials. In this paper we give approximate explicit formulas for both the real and imaginary parts of the th zero of and show that the approximation order of these new formulas to the exact zeros of the Bessel polynomials is for fixed . The approach followed in this paper is simple and based on three items. The first is the electrostatic interpretation of the zeros of polynomials satisfying second-order differential equations [15–17], the second is a simple curve fitting of numerical data, and the third is the known fact that the points of well-defined curves in the complex plane are limit points of the zeros of the normalized Bessel polynomials
Estudios de estabilidad transitoria en sistemas eléctricos industriales con generación propia interconectados con el sistema de transmisión
Calderón-Guizar, J.G.;
Ingeniería, investigación y tecnología , 2010,
Abstract: aiming to ensure continuity in the electrical supply to critical processes, the electrical systems of large industrial plants, i.e. gas, and petrochemical industries usually posses local generation. should the local generation be enough to satisfy the demand of the plant, then the interconnection with the public grid is commonly used as an important support for emergency conditions. this paper is concerned with the dynamical performance of two interconnected industrial power systems tied to the transmission system. simulation results indicate that the frequency performance of one of the industrial plants, after the transients caused by the loss of the tie with the transmission system have died out, is greatly improved if both industrial plants remain connected after the disturbance.
Análisis modal de oscilaciones electromecánicas en sistemas eléctricos de potencia
Calderón-Guizar, J.G.;
Ingeniería, investigación y tecnología , 2008,
Abstract: electromechanical oscillations in any electrical power system is a typical characteristic of this kind of systems. provided the damping associated with these oscillations lies above of a minimum specified value, the occurrence of these oscillation is not considered as a threat to the system operation. this paper focuses the attention on the application of modal analysis for assessing the dynamical behavior of a power system subjected to small disturbances for different operating conditions and transmission system topologies, as well. the reported results indicate, that modal analysis enables a straight identification of the causes that contribute negatively to the damping of the electromechanical modes.
Electrical and morphological properties of low resistivity Mo thin films prepared by magnetron sputtering
Gordillo, G.;Mesa, F.;Calderón, C.;
Brazilian Journal of Physics , 2006, DOI: 10.1590/S0103-97332006000600049
Abstract: mo thin films have been deposited using a dc magnetron sputtering system with an s-gun configuration electrode and characterized electrically and morphologically. the influence of the sputtering gas pressure and glow discharge (gd) power, on the electrical resistivity of mo thin films and on the contact resistivity of mo to cu(in,ga)se2 (cigs) films was determined through an exhaustive parameter study. this study also allowed us to find the conditions to deposit mo films with suitable properties for its use as back contact of solar cells based on cigs. resistivities smaller than 1x10-4 w.cm and contact resistivities smaller than 0.3 wcm2 were found. mo films with these characteristics are suitable for back contacts in solar cells based on cigs. it was also found that the mo thin films, deposited by dc magnetron sputtering on cigs thin films, act effectively as ohmic contacts. the main contribution of this work was to obtain mo thin films with adequate properties to be used as back contact for cigs based solar cells using a dc sputtering system with s-gun configuration electrode, which allows growing the film with better surface quality and at a higher deposition rate than those deposited using the conventional planar rf sputtering system.
Metamorfismo y deformación de la Formación Tobífera en la cordillera Riesco, región de Magallanes, Chile: evidencias para su evolución tectónica Metamorphism and deformation of the Tobifera Formation in the Cordillera Riesco, Region of Magallanes, Chile: Evidences for its tectonic evolution
G. Galaz,F. Hervé,M. Calderón
Revista de la Asociación Geológica Argentina , 2005,
Abstract: La Formación Tobífera (150 Ma) se deposita en parte contemporánea al Complejo Ofiolítico Sarmiento durante un ambiente geodinámico de rifting de la cuenca de Rocas Verdes. Posteriormente se depositan en concordancia sobre ella las unidades cretácicas de las Formaciones Zapata, Punta Barrosa y Cerro Toro. En Cordillera Riesco está compuesta por tobas silíceas, tobas soldadas silíceas, limolitas negras cuarcíferas y lutitas cuarcíferas, afectadas por una deformación milonítica, que desarrolla indicadores cinemáticos dúctiles inversos, con menor componente dextral, que sugiere un movimiento dextral-inverso para la zona de falla. La mineralogía metamórfica y la aplicación de geotermobarómetros reflejan que esta zona milonítica alcanzó condiciones P-T de 6,37 ± 1,1 kb y 399 ± 64°C, respectivamente. Esto sugiere que estas rocas alcanzaron una profundidad entre 19-26 km, posiblemente producto de un evento de subducción reversa que afectó a estas rocas. Además, determinan una facies esquistos verdes para asociaciones minerales en la matriz y facies prehnita-actinolita para asociaciones minerales en vetillas. Este último evento metamórfico sería de carácter retrógrado. Clastos deformados de la Formación Tobífera en brechas de la Formación Cerro Toro, evidencian que ésta se exhumó antes del Cretácico superior. La configuración actual de las estructuras en Cordillera Riesco posiblemente se debe a rotaciones hacia el oeste, producidas dentro del desarrollo de la faja plegada y corrida de Magallanes. The Tobífera Formation (150 Ma) was in part deposited contemporaneously with the Sarmiento Ophiolitic Complex during the rifting stage of the Rocas Verdes Basin. Later, the Cretaceous Zapata, Punta Barrosa and Cerro Toro Formations were deposited conformably on top of the Tobìfera. In Cordillera Riesco, it is composed of siliceous tuffs, siliceous welded tuffs, quartzose black shales and siltstones. It is affected by a mylonitic deformation that developed different ductile reverse kinematic indicators, with a minor dextral component which suggest a reverse- dextral movement of the fault zone. The metamorphic mineralogy indicates that the greenschist facies conditions were reached for the matrix forming minerals, and prehnite-actinolite facies in mineral associations in retrograde cross-cutting veinlets. Geothermobarometric calculations indicate that this mylonite zone reached 6.3 ± 1.1 kb and 399 ± 64°C. These values suggest that these rocks reached a depth between 19 and 26 km, maybe during a reverse subduction episode in the area. Deformed clasts of Tobífera Formation
Transient Stability Studies on Industrial Power Systems Interconnected to the Transmission Grid
Calderón–Guizar J.G.
Ingeniería, investigación y tecnología , 2010,
Abstract: Aiming to ensure continuity in the electrical supply to critical processes, the electrical systems of large industrial plants, i.e. gas, and petrochemical industries usually posses local generation. Should the local generation be enough to satisfy the demand of the plant, then the interconnection with the public grid is commonly used as an important support for emergency conditions. This paper is concerned with the dynamical performance of two interconnected industrial power systems tied to the transmission system. Simulation results indicate that the frequency performance of one of the industrial plants, after the transients caused by the loss of the tie with the transmission system have died out, is greatly improved if both industrial plants remain connected after the disturbance.
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