Search results for "49"
showing 10 items of 1208 documents
10 años de la REEC. Una mirada en perspectiva
2005
Con motivo del décimo aniversario de la REEC, este artículo realiza una panorámica de lo que ha sido la revista en ésta su primera década de vida. Los motivos del nacimiento de la REEC, su encuadre institucional en la SEEC y sus objetivos se especifican en la primera parte de este artículo. También se presenta en ella su habitual estructura organizativa y su manera de proceder a la hora de confeccionar cada número anual, los sistemas de selección de artículos en casa sección y otras cuestiones de interés. En segundo lugar se ofrece la evolución de las cuestiones elegidas para constituir el tema de la sección monográfica. Ellas nos van dibujando un singular camino que deja constancia de las …
CONTROVERSIAS EN TORNO AL SOFTWARE LIBRE: PRÁCTICAS Y DISCURSOS EN LA DOCENCIA UNIVERSITARIA VALENCIANA
2008
Resumen basado en el de la publicación La progresiva implantación del software libre en los ámbitos universitarios, se acompaña de un discurso construido sobre las controversias que rodean a esta tecnología. Para el análisis de este problema se utiliza el modelo de 'espacios controversiales' propuesto por Nudler, definiendo uno de estos espacios en torno a la aplicación de las tecnologías informáticas en las enseñanzas universitarias. El supuesto es que el debate sobre el copyleft está alcanzando también al discurso pedagógico que acompaña a las aplicaciones de estas tecnologías. Este modelo es el que se trata de aplicar al estudio de cómo se formulan tales controversias en la difusión del …
Unified understanding of intrinsic and extrinsic controls of dissolved organic carbon reactivity in aquatic ecosystems
2022
Despite our growing understanding of the global carbon cycle, scientific consensus on the drivers and mechanisms that control dissolved organic carbon (DOC) turnover in aquatic systems is lacking, hampered by the mismatch between research that approaches DOC reactivity from either intrinsic (inherent chemical properties) or extrinsic (environmental context) perspectives. Here we propose a conceptual view of DOC reactivity in which the combination of intrinsic and extrinsic factors controls turnover rates and determines which reactions will occur. We review three major types of reactions (biological, photochemical, and flocculation) from an intrinsic chemical perspective and further define t…
Declaracion magistral sobre las [sic] Emblemas de Andres Alciato : con todas las historias, antiguedades, moralidad, y doctrina tocante a las buenas …
1615
Escut calc. de D. Diego Hurtado de Mendoza, a qui es dedica l'obra, a la port. Grav. calc. Sign.: œ8, A-Nnn8, Ooo4 Errates de fol.: repeteix 182, 183, 381, 454, de 438 passa a 446
Chemical composition of modern and fossil Hippopotamid teeth and implications for paleoenvironmental reconstructions and enamel formation – Part 1: M…
2012
Bioapatite in mammalian teeth is readily preserved in continental sediments and represents a very important archive for reconstructions of environment and climate evolution. This project provides a comprehensive data base of major, minor and trace element and isotope tracers for tooth apatite using a variety of microanalytical techniques. The aim is to identify specific sedimentary environments and to improve our understanding on the interaction between internal metabolic processes during tooth formation and external nutritional control and secondary alteration effects. Here, we use the electron microprobe to determine the major and minor element contents of fossil and modern molar enamel, …
Calpains promote α2β1 integrin turnover in nonrecycling integrin pathway
2012
A novel virus- and integrin clustering–specific pathway diverts integrin from its normal endo/exocytic traffic to a nonrecycling degradative endosomal route. Clustering of α2β1 integrin causes redistribution of the integrin to perinuclear endosomes, leading to enhanced integrin turnover promoted by calpains.
On the Efficacy of PCM to Shave Peak Temperature of Crystalline Photovoltaic Panels: An FDM Model and Field Validation
2013
The exploitation of renewable energy sources and specifically photovoltaic (PV) devices have been showing significant growth; however, for a more effective development of this technology it is essential to have higher energy conversion performances. PV producers often declare a higher efficiency respect to real conditions and this deviation is mainly due to the difference between nominal and real temperature conditions of the PV. In order to improve the solar cell energy conversion efficiency many authors have proposed a methodology to keep the temperature of a PV system lower: a modified crystalline PV system built with a normal PV panel coupled with a Phase Change Material (PCM) heat stor…
Analytical Investigation and Control System Set-up of Medium Scale PV Plants for Power Flow Management
2012
In the field of photovoltaic (PV) plants and energy conversion from renewable sources, a large part of the technical literature is more devoted to practical aspects (new solar cells, electrically driven PV panels, safety, reduction of parasitic currents, etc.) than to theoretical investigations. Despite this tendency, this paper presents a mathematical analysis of a medium scale photovoltaic power generation system connected to the distribution network and of its control system. In such a system, the conversion stage is unique due to the absence of a boost chopper. The conducted analysis leads to the interesting conclusion that the inverter used in the plant presents two degrees of freedom,…
Proof of Concept of an Irradiance Estimation System for Reconfigurable Photovoltaic Arrays
2015
In order to reduce the mismatch effect caused by non-uniform shadows in PV arrays, reconfigurable interconnections approaches have been recently proposed in the literature. These systems usually require the knowledge of the solar radiation affecting every solar module. The aim of this work is to evaluate the effectiveness of three irradiance estimation approaches in order to define which can be well suited for reconfigurable PV arrays. It is presented a real-time solar irradiance estimation device (IrradEst), implementing the three different estimation methods. The proposed system is based on mathematical models of PV modules enabling to estimate irradiation values by sensing a combination …
Evaluation of the Water Scarcity Energy Cost for Users
2013
Abstract: In systems experiencing water scarcity and consequent intermittent supply, users often adopt private tanks that collect water during service periods and supply users when the service is not available. The tank may be fed by gravity or by private pumping stations depending on the network pressure level. Once water resources are collected, the tank can supply users by gravity if it is located on the rooftop or by additional pumping if underground. Private tanks thus increase the energy cost of the water supply service for users by introducing several small pumping structures inside the network. The present paper aims to evaluate this users’ energy cost for different private tank con…