Didáctica básica para la construcción de la esfera basada en la estructura del cubo: una lección elemental en la enseñanza aprendizaje de los sólidos para todos los estudiantes de dibujo

El objetivo de este artículo es explicar un proceso de dibujo que involucra el estudio de los elementos estructurales de la esfera. Es un planteamiento dirigido a los estudiantes de los cursos de dibujo quienes deben aprender a percibir las cualidades volumétricas del objeto real y representarlo por medio de los elementos estructurales intrínsecos. Se definen dos maneras de abordar la representación de la esfera, una para estudiantes novatos, y otra para estudiantes avanzados. Se repasa la estructura del cubo, y los conceptos básicos de la perspectiva, el método de visado, el dominio de las proporciones del cubo, la relación de los ángulos del cubo respecto de los lados, la estructura portante, los elementos básicos de la estructura del cubo. Se estudia además la construcción de las elipses en los tres planos cartesianos, y las diferencias de calidad tonal que se deben de utilizar. Todos estos procedimientos se enumeran en el presente artículo, explicados paso a paso, por medio de ilustraciones. También, se muestran varios ejemplos de la esfera en posiciones sencillas y extremas que demuestran la variación de los ejes básicos de acuerdo a su posición y dirección en el espaci

VAChT knock-down mice show normal prepulse inhibition but disrupted long-term habituation

The neurotransmitter acetylcholine (ACh) plays a crucial role in both the central and peripheral nervous system. Central cholinergic transmission is important for cognitive functions and cholinergic disruptions have been associated with different neural disorders. We here tested the role of cholinergic transmission in basic cognitive functions, i.e. in prepulse inhibition (PPI) and short-term habituation (STH) as well as long-term habituation (LTH) of startle using mice with a 65% knockdown (KD) of the vesicular ACh transporter (VAChT). These mice are slow in refilling cholinergic synaptic transmitter vesicles, leading to a reduced cholinergic tone. Prepulse inhibition has been assumed to be mediated by cholinergic projections from the midbrain to the reticular formation. Surprisingly, PPI and STH were normal in these mice, whereas LTH was disrupted. This disruption could be rescued by pre-testing injections of the ACh esterase inhibitor galantamine, but not by post-testing injections. The lack of a PPI deficit might be because of the fact that VAChT KD mice show disruptions mainly in prolonged cholinergic activity, therefore the transient activation by prepulse processing might not be sufficient to deplete synaptic vesicles. The disruption of LTH indicates that the latter depends on a tonic cholinergic inhibition. Future experiments will address which cholinergic cell group is responsible for this effect

Capacitance Measurements for Subcell Characterization in Multijunction Solar Cells.

On this paper we present an alternative way to analyze de electronic properties of each subcell from the complete device. By illuminating the cell with light sources which energy is near one of the subcell bandgaps, it is possible to “erase” the presence of such subcell on the CV curve. The main advantages of this technique are that it is not destructive, it can be measured on the complete cell so can be easily implemented as a diagnostic technique for controlling electronic deviations

Coal Quality Management Model For Dome Storage (DS-CQMM)

Coal quality (ash, sulphur, moisture, and heating value) is one of the fundamental concerns for both coal mines and power plants. In order to deliver uniform coal quality to the power plant, there is a need for realtime monitoring of coal quality from the mine to the coal stockpiles. The specific problem represents the process of stacking the coal inside an enclosed facility such as a dome. The objective of this research was to develop a custom-made and integrated coal quality management model for dome storage (DS-CQMM). The DS-CQMM merges existing technology in surface mines, such as coal analysers, together with automation technologies, information technologies (IT), and mathematical models. The DS-CQMM is organized into four major sections: Delay Time application, Stacker application, Reclaimer application, and Live Stockpile application. A sub-process called Volume Calculation is embedded in Stacker application, while an additional feature called Forecast tool is included in the Reclaimer application. The DS-CQMM model was developed for a surface coal mine in the southern USA

Spanish adaptation and factor structure of the Denison Organizational Culture Survey

[EN]: This article presents a Spanish adaptation of the Denison Organizational Culture Survey, a questionnaire designed to evaluate organizational culture. This survey consists of 60 items, grouped in 12 subscales, which identify 4 cultural dimensions. These dimensions have been widely studied and their influence in organizational effectiveness has been accepted. This adaptation was applied to 488 participants, and analysed with confirmatory factor analysis. Results show adequate psychometric properties, so it can be concluded that the Spanish adaptation almost completely replicates the structure of the original version in English. © 2009 Psicothema.[ES]: En este estudio se presenta la adaptación al castellano del Denison Organizational Culture Survey, una encuesta diseñada para la evaluación de la cultura organizativa. Está compuesta por 60 ítems agrupados en 12 subescalas que identifican a su vez 4 dimensiones culturales, de aceptada influencia en la efectividad organizacional. La muestra consta de 488 personas y se ha utilizado análisis factorial confirmatorio. Los resultados obtenidos señalan unas propiedades psicométricas adecuadas, por lo que cabe concluir que la adaptación española replica casi en su totalidad la estructura planteada en la versión original.Este trabajo se enmarca en un proyecto de investigación aprobado por el Ministerio de Educación y Ciencia titulado: «Influencia de la cultura organizativa y el flujo de conocimiento sobre el rendimiento científico de los grupos de I+D tecnológicos. Aplicación en la Universidad Politécnica de Valencia» (SEJ2005_08603).Peer Reviewe

Adaptación al castellano y estructura factorial del Denison

6 pages, 4 tables[ES]En este estudio se presenta la adaptación al castellano del Denison Organizational Culture Survey, una encuesta diseñada para la evaluación de la cultura organizativa. Está compuesta por 60 ítems agrupados en 12 subescalas que identifican a su vez 4 dimensiones culturales, de aceptada influencia en la efectividad organizacional. La muestra consta de 488 personas y se ha utilizado análisis factorial confirmatorio. Los resultados obtenidos señalan unas propiedades psicométricas adecuadas, por lo que cabe concluir que la adaptación española replica casi en su totalidad la estructura planteada en la versión original.[EN]Spanish adaptation and factor structure of the Denison Organizational Culture Survey. This article presents a Spanish adaptation of the Denison Organizational Culture Survey, a questionnaire designed to evaluate organizational culture. This survey consists of 60 items, grouped in 12 subscales, which identify 4 cultural dimensions. These dimensions have been widely studied and their influence in organizational effectiveness has been accepted. This adaptation was applied to 488 participants, and analysed with confirmatory factor analysis. Results show adequate psychometric properties, so it can be concluded that the Spanish adaptation almost completely replicates the structure of the original version in English.Este trabajo se enmarca en un proyecto de investigación aprobado por el Ministerio de Educación y Ciencia titulado: «Influencia de la cultura organizativa y el flujo de conocimiento sobre el rendimiento científico de los grupos de I+D tecnológicos. Aplicación en la Universidad Politécnica de Valencia» (SEJ2005_08603).Peer reviewe

Stochastic stabilization of cosmological photons

The stability of photon trajectories in models of the Universe that have constant spatial curvature is determined by the sign of the curvature: they are exponentially unstable if the curvature is negative and stable if it is positive or zero. We demonstrate that random fluctuations in the curvature provide an additional stabilizing mechanism. This mechanism is analogous to the one responsible for stabilizing the stochastic Kapitsa pendulum. When the mean curvature is negative it is capable of stabilizing the photon trajectories; when the mean curvature is zero or positive it determines the characteristic frequency with which neighbouring trajectories oscillate about each other. In constant negative curvature models of the Universe that have compact topology, exponential instability implies chaos (e.g. mixing) in the photon dynamics. We discuss some consequences of stochastic stabilization in this context.Comment: 4 pages, 3 postscript figures in color which are also appropriate for black and white printers; v2 emphasizes relevance to flat as well as negatively curved cosmologies; to appear in J. Phys.