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Search Results: 1 - 10 of 299387 matches for " J. Rubio "
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Diálogo con Valentín Barenblit acerca de la supervisión institucional en los Equipos de Salud Mental.
J Leal Rubio
Revista de la Asociación Espa?ola de Neuropsiquiatría , 1993,
Abstract: Sin resumen.
Enfoques y modelos de evaluación del e-learning. [ Focus and models of evaluation of the e-learning ]
Rubio. M.J.
Revista Electrónica de Investigación y Evaluación Educativa , 2003,
Abstract: The aim of this article is to present the state of arts about e-learning evaluation. Different evaluative approaches, different models, tools and experiencies are showed, in order to determine the quality of virtual learning. Two main approaches are showed: partial evaluation, with emphasis in some aspects of e-learning (materials, technology resources, teaching, etc.) and global evaluation, that uses management quality models and the practice of benchmarking.
Rehabilitación Urbana en Espa a (1989-2010). Barreras actuales y sugerencias para su eliminación
Rubio del Val, J.
Informes de la Construccion , 2011,
Abstract: At the beginning of this century, the cities of our country face a challenge that, in quantitative terms, goes beyond the action referred to the rehabilitation of historic centres and XIX century extensions. This challenge is the rehabilitation of a specific fabric of our cities: neighbourhoods built in the period of 1940-1980, which are undergoing processes of serious urban degradation and can be identified as vulnerable urban areas. This article discusses the strategies taken from the various government levels in urban rehabilitation, and the experiences initiated, with the aim of detecting what are the main barriers of all kind (legal, social, economic, cultural) that prevent the systematic practice of these initiatives, which today still have an experimental and minority character, and to forward proposals for action to achieve comprehensive and systematic urban rehabilitation in these neighbourhoods. Al inicio de este siglo XXI, las ciudades de nuestro país tienen ante sí un reto que en términos cuantitativos supera, con mucho, al referido a la actuación de rehabilitación sobre los centros históricos y primeros ensanches. Se trata de la rehabilitación de un tejido específico de nuestras ciudades, los barrios de bloque abierto construidos entre 1940-1980, en los que se están produciendo graves procesos de degradación urbana y que pueden caracterizarse como áreas urbanas vulnerables. Este artículo analiza las estrategias emprendidas desde las diversas administraciones públicas en materia de rehabilitación urbana, así como las experiencias iniciadas, con el objetivo de detectar cuáles son las principales barreras de todo tipo (legales, sociales, económicas, culturales) que impiden una práctica sistemática de estas iniciativas, que hoy todavía tienen un carácter experimental y minoritario, y avanzar propuestas de acción para conseguir la rehabilitación urbana integral y sistemática de estos barrios.
On the propriety of the posterior of hierarchical linear mixed models with flexible random effects distributions
F. J. Rubio
Statistics , 2014,
Abstract: The use of improper priors in the context of Bayesian hierarchical linear mixed models has been studied under the assumption of normality of the random effects. We study the propriety of the posterior under more flexible distributional assumptions and general improper prior structures.
On the Independence Jeffreys prior for skew--symmetric models with applications
F. J. Rubio,B. Liseo
Statistics , 2013,
Abstract: We study the Jeffreys prior of the skewness parameter of a general class of scalar skew--symmetric models. It is shown that this prior is symmetric about 0, proper, and with tails $O(\lambda^{-3/2})$ under mild regularity conditions. We also calculate the independence Jeffreys prior for the case with unknown location and scale parameters. Sufficient conditions for the existence of the corresponding posterior distribution are investigated for the case when the sampling model belongs to the family of skew--symmetric scale mixtures of normal distributions. The usefulness of these results is illustrated using the skew--logistic model and two applications with real data.
Survival and lifetime data analysis with a flexible class of distributions
Francisco J. Rubio,Yili Hong
Statistics , 2015,
Abstract: We introduce a general class of continuous univariate distributions with positive support obtained by transforming the class of two-piece distributions. We show that this class of distributions is very flexible, easy to implement, and contains members that can capture different tail behaviours and shapes, producing also a variety of hazard functions. The proposed distributions represent a flexible alternative to the classical choices such as the log-normal, Gamma, and Weibull distributions. We investigate empirically the inferential properties of the proposed models through an extensive simulation study. We present some applications using real data in the contexts of time-to-event and accelerated failure time models. In the second kind of applications, we explore the use of these models in the estimation of the distribution of the individual remaining life.
Effects of pork vs veal consumption on serum lipids in healthy subjects Efecto del consumo de cerdo y de ternera sobre el perfil lipídico de sujetos sanos
J. A. Rubio,M. A. Rubio,L. Cabrerizo,P. Burdaspal
Nutrición Hospitalaria , 2006,
Abstract: AIMS: To analyse the influence of lean pork (P) and veal (V) consumption on the lipid profile of healthy subjects within the framework of a healthy diet comprising low levels of total fat (TF), saturated fatty acids (SFA) and cholesterol. DESIGN: Double-crossover, randomized and controlled trial SUBJECTS: 44 healthy individuals (22 male and 22 female), recruited voluntarily from the University Complutense of Madrid. The weight and lipid profiles of these volunteers were normal and their dietary patterns were typical for people in our area. INTERVENTIONS: The study comprised 4 phases: stabilisation phase (5 weeks), the participants followed their normal diet; second phase (6 weeks), half of the subjects, were randomised to lean pork or veal consumption, 150 g per day, for their main meal of the day; washout period (5 weeks) and final phase, which was the second phase of intervention (6 weeks). During the intervention stages, only the main meal of the day was taken in the Hospital. The rest of the subjects' diets consisted of different fortnightly menus designed in accordance with the recommendations of the Spanish Society of Arteriosclerosis (SEA). RESULTS: After both stages of intervention had been completed, there was a mean reduction of 5.5% in lowdensity lipoprotein cholesterol. However, after each intervention there were no significant differences between those who had consumed P, 2.62 (0.55) mmol/L and those who had consumed V, 2.71 (0.47) mmol/L. No differences were observed in any of the other parameters between those who had consumed P and those who had consumed V. CONCLUSIONS: Lean pork and veal produces similar effects on the lipid profiles of healthy subjects. Its consumption, as part of the saturated fat and cholesterolcontrolled diet, could therefore be included in food guidelines, both for normal and therapeutic diets. OBJETIVO: Analizar la influencia del consumo de carne magra de cerdo (P) y de ternera (V) en el perfil lipídico de sujetos sanos, cuando se realiza dentro de un patrón de dieta saludable con bajo contenido en grasa total (TF), ácidos grasos saturados (SFA) y en colesterol. DISE O: Ensayo cruzado doble, aleatorizado y controlado. SUJETOS: 44 sujetos sanos (22 varones y 22 mujeres), reclutados de forma voluntaria de la Universidad Complutense de Madrid. Los pesos y los perfiles lipídicos de estos voluntarios y su patrón de alimentación eran típicos de las personas de nuestra área. INTERVENCIONES: El estudio consta de 4 fases: fase de estabilización (5 semanas), los participantes seguían su dieta normal; segunda fase (6 semanas)
Degradación térmica de nanocomposites TEOS/resol y y-APS/resol
Soriano, D.,Mazo, A.,Rubio, J.,Rubio, F.
Boletín de la Sociedad Espa?ola de Cerámica y Vidrio , 2006,
Abstract: The thermal degradation of TEOS-resol and APS-resol nanocomposites prepared by the sol-gel process has been studied in this work. Kinetic studies based on activation energies, reaction orders and pre-exponential factors as well as degradation analysis based on IPDT and IDT have been used in this work. For such studies thermograms at different heating velocities have been used. Activation energies between 100 and 200 kJ.mol-1 have been obtained in this work. Such values are of the same order as those found in the literature. On the other hand reaction orders vary between 1,5 and 3,0, depending on the nanocomposite analysed and the procedure used. At the same time IPDT values have been always higher than 500 oC reaching values close to 650 oC in some cases. Finally half life times calculated at a degradation temperature of 505 oC and conversions of 95% have reached 1100 minutes for the best nanocomposites. All of these results have been correlated with IR spectra showing that those nanocomposites where resol molecules react with hydrolysed TEOS or APS they give the high degradation resistance. En este trabajo se ha estudiado la degradación térmica de nanocomposites resol-alcóxido (TEOS o APS) preparados mediante el proceso sol-gel. Esta degradación se ha caracterizado tanto mediante estudios cinéticos (Energía de Activación, orden de reacción y factor pre-exponencial) como por estudios degradativos (IPDT, IDT). En todos los casos la base de estudio han sido los termogramas realizados a distintas velocidades. Los valores de las energías de activación encontrados han sido similares a nanocomposites recogidos en la bibliografía (con valores comprendidos entre 100 y 200 kJ.mol-1). Por otro lado, los órdenes de reacción han estado comprendidos entre 1,5 y 3,0 dependiendo del método utilizado y del nanocomposite analizado. Los valores de IPDT para todos los nanocomposites han sido superiores a 500 oC llegando en algunos casos a los 650 oC. Finalmente se han calculado los valores del tiempo de vida media para una temperatura de 505 oC y una degradación del 95% del nanocomposite, habiéndose alcanzado valores superiores a los 1100 minutos. Todos estos resultados se han correlacionado con los espectros IR en los que se ha observado que las mayores resistencias se alcanzan en aquellos nanocomposites en los que la resina interacciona con las partículas del alcóxido.
Estudio de la hidrólisis del trietilborato por espectroscopía infrarroja: evaluación de geles de borosilicato
Pe?a-Alonso, R.,Rubio, F.,Rubio, J.
Boletín de la Sociedad Espa?ola de Cerámica y Vidrio , 2007,
Abstract: Triethylborate (TEB) is a boron alkoxide largely used in the synthesis of sol-gel prepared materials. This method requires the hydrolysis and condensation of the synthesis reagents, usually alkoxides, for obtaining a gel which can be transformed into different materials, such as glasses or ceramics, as a function of the thermal treatment applied. Infrared spectroscopy is one of the routine techniques used in the study of the sol-gel reaction due to the easy handling of the sample and the fast speed of the analysis. In this work, the study of the hydrolysis and condensation reactions of TEB is carried out by studying their vibrational bands located at 893 cm-1, which shows a continuous decrease as the hydrolysis is performed, and 1194 cm-1, which increases with the proceed of the condensation. A proposed calibration line for the quantitative analysis of the hydrolysis extension of TEB in several TEOS-TEB gels evidence that between 20 and 33% of the TEB molecules have not been hydrolysed during the sol-gel reaction for forming such gels. El trietilborato (TEB) es un alcóxido de boro muy usado en las síntesis de materiales preparados por el método sol-gel. Este método implica la hidrólisis y condensación de los reactivos de síntesis, generalmente alcóxidos, para obtener un gel que posteriormente puede dar lugar a diversos tipos de materiales, tanto cerámicos como vítreos, dependiendo del tratamiento térmico posterior. Una de las técnicas de rutina empleadas en el seguimiento de las reacciones sol-gel es la espectroscopía infrarroja por la facilidad de manipulación de la muestra y rapidez del análisis. En este trabajo se realiza un estudio de las reacciones de hidrólisis y condensación del alcóxido TEB a través del seguimiento de las bandas de absorción situadas a 893 cm-1, que muestra una disminución a medida que avanza la hidrólisis del alcóxido, y 1194 cm-1 que crece con el avance de la condensación. La recta de calibrado propuesta para el análisis cuantitativo de la extensión de la hidrólisis del TEB en geles de TEOS-TEB pone de manifiesto que entre un 20 y un 33% de las moléculas de TEB no han sido hidrolizadas durante la reacción sol-gel de formación de dichos geles.
Bayesian modelling of skewness and kurtosis with two-piece scale and shape distributions
F. J. Rubio,M. F. J. Steel
Statistics , 2014,
Abstract: We formalise and generalise the definition of the family of univariate double two--piece distributions, obtained by using a density--based transformation of unimodal symmetric continuous distributions with a shape parameter. The resulting distributions contain five interpretable parameters that control the mode, as well as the scale and shape in each direction. Four-parameter subfamilies of this class of distributions that capture different types of asymmetry are discussed. We propose interpretable scale and location-invariant benchmark priors and derive conditions for the propriety of the corresponding posterior distribution. The prior structures used allow for meaningful comparisons through Bayes factors within flexible families of distributions. These distributions are applied to data from finance, internet traffic and medicine, comparing them with appropriate competitors.
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