977 resultados para formulação multi-material ALE


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Los frutos secos representan un peso notable en la producción final agrícola española, siendo nuestro país el segundo productor mundial de almendra (55.000 tm grano) y el cuarto de avellana (9.000 tm grano). En el caso del avellano, la superficie de España es de unas 25.000 ha (MAPA, 2000), concentrándose el 95 % de la misma en Cataluña y, más concretamente en Tarragona (18.000 ha), donde el avellano es, en diversas comarcas, una importante fuente de ingresos. Durante las últimas décadas, el sector ha estado sometido a fuertes crisis debido al descenso de precios causado, entre otros motivos, por la existencia o no de acuerdos comerciales entre la UE y Turquía sobre este fruto seco, por las oscilaciones del dólar y la competencia creciente de Turquía, que produce casi el 75 % del total mundial y cuyos costes de producción son más reducidos, por disponer de mano de obra más barata y mejores condiciones edafoclimáticas para el cultivo. Un problema adicional de la avellana española en dicho periodo, fue la poca calidad del producto obtenido, motivada por la realización inadecuada de una serie de prácticas de recogida y de postcosecha. La variedad 'Negret' es la base de la producción de avellana española para industria y, junto con la ‘Pauetet’, constituyen el tipo comercial ‘negreta’ que es el que obtiene mejor precio en el mercado nacional. Ello es debido a sus buenas características organolépticas y elevada aptitud al tostado, que constituye el punto de partida de la mayoría de aplicaciones comerciales. Por otra parte, constituye, también, la base de la producción de la Denominación de Origen ‘Avellana de Reus’. Tradicionalmente esta variedad adolece de importantes problemas de tipo agronómico (poco vigor, rebrotante, sensible a clorosis férrica, asfixia del suelo, muy virosada, etc.) y comercial (facilidad de enranciamiento, calibres pequeños, etc.), situación que ha inducido, en la última década, a la introducción de variedades foráneas (‘Tonda Giffoni’ y ‘Tonda Romana’) que en principio no presentan estos problemas. Sin embargo, la sustitución de la variedad autóctona ‘Negret’ por otras nuevas supondría la pérdida de un carácter diferencial para la producción española, que debe evaluarse con sumo cuidado.

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En las colecciones del IRTA-Mas Bové se han caracterizado más de 150 clones de nogal procedentes de prospección, material extranjero y de selecciones de distintos programas de mejora. El material se ha caracterizado agronómicamente siguiendo los descriptores del IPGRI (1994). Actualmente existen fichas descriptivas muy amplias de 43 accesiones. Toda esta información sobre el comportamiento del material vegetal en las condiciones climáticas de Tarragona, tiene interés a nivel científico y es muy válida para posibles plantaciones con nuevo material. El estudio de los caracteres de sensibilidad a Bacteriosis y afección de la caída prematura de flores (PFA), en dos decendencias de nogal de cruzamientos controlados, ha permitido obvervar que estos caracteres tienen una herencia compleja. Se ha establecido la virulencia de distintos aislados de Xanthomonas arboricola pv. juglandis, en nogal. Los aislados más virulentos se han utilizado para establecer un modelo de predicción, en condiciones de laboratorio, de esta bacteria en nogal. La temperatura a la que la severidad de la enfermedad es máxima es 26ºC. A esta temperatura un aumento en la duración del período de humedad relativa elevada de 0-24 horas, produce un aumento de la afección. En los próximos años, este modelo de predicción se validará en campo. Si los resultados son positivos, permitirán racionalizar los tratamientos para la Bacteriosis en las plantaciones de nogal. Los primeros resultados de un control de la iluminación en el interior de las copas de los árboles, realizado mediante medidas de iluminación interceptadas con un ceptómetro Delta T (SunScan), han puesto de manifiesto que la gran influencia de la luz en el crecimiento anual de las ramas. Así, en la formación y poda de los árbles hay que tener presente estos resultados, en especial en las formaciones en ejes libres, y favorecer la máxima entrada de luz en el interior de la copa de los árboles.

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Creptotrema creptotrema Travassos, Artigas & Pereira, 1928, a digenetic trematode parasite of Leporinus elongatus, is redescribed from the type-material with additional morphological data and original figures.

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This paper presents an outline of rationale and theory of the MuSIASEM scheme (Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism). First, three points of the rationale behind our MuSIASEM scheme are discussed: (i) endosomatic and exosomatic metabolism in relation to Georgescu-Roegen’s flow-fund scheme; (2) the bioeconomic analogy of hypercycle and dissipative parts in ecosystems; (3) the dramatic reallocation of human time and land use patterns in various sectors of modern economy. Next, a flow-fund representation of the MUSIASEM scheme on three levels (the whole national level, the paid work sectors level, and the agricultural sector level) is illustrated to look at the structure of the human economy in relation to two primary factors: (i) human time - a fund; and (ii) exosomatic energy - a flow. The three levels representation uses extensive and intensive variables simultaneously. Key conceptual tools of the MuSIASEM scheme - mosaic effects and impredicative loop analysis - are explained using the three level flow-fund representation. Finally, we claim that the MuSIASEM scheme can be seen as a multi-purpose grammar useful to deal with sustainability issues.

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Economic development goes hand in hand with an increase in the consumption of natural resources. Some analysts use material flows to describe such relationship [Eurostat 2001, Weisz et al., 2006], or exergy [Ayres et al., 2003]. Instead this paper will use a characterisation of the exosomatic energy metabolism based on expected benchmark values to describe possible constraints to economic development posed by available human time and energy. The aim of the paper is to identify types of exosomatic energy metabolism of different societies to interpret its consequences for economic development. This is done with the application of the accounting methodology called Multi-Scale Integrated Analysis of Societal Metabolism (MSIASM) to the particular case of energy metabolism for the analysis of the economies of Brazil, Chile and Venezuela.

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The goal of this paper is to study the role of multi-product firms in the market provision of product variety. The analysis is conducted using the spokes model of non-localized competition proposed by Chen and Riordan (2007). Firstly, we show that multi-product firms are at a competitive disadvantage vis-a-vis single-product firms and can only emerge if economies of scope are sufficiently strong. Secondly, under duopoly product variety may be higher or lower with respect to both the first best and the monopolistically competitive equilibrium. However, within a relevant range of parameter values duopolists drastically restrict their product range in order to relax price competition, and as a result product variety is far below the efficient level.

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We analyse natural resource use dynamics in the Mexican economy during the last three decades. Despite low and uneven economic growth, the extraction and use of materials in the Mexican economy has continuously increased during the last 30 years. In this period, population growth rather than economic growth was the main driving force for biophysical growth. In addition, fundamental changes have taken place in the primary sectors, in manufacturing, and in household consumption and these are reflected in an increasing emphasis on the use of fossil fuels and construction materials. Mexico’s economy has been strongly influenced by international trade since the country commenced competing in international markets. In the 1970s, Mexico mainly exported primary resources. This pattern has changed and manufactured goods now have a much greater importance due to a boom in assembling industries. In contrast with other Latin American countries, Mexico has achieved a diversification of production, moving towards technology-intensive products and a better mix in its export portfolio. However, crude oil exports still represent the single most important export good. Mexico’s material consumption is still well below the OECD average but is growing fast and the current resource use patterns may well present serious social and environmental problems to the medium and long term sustainability of Mexico’s economy and community. Information on natural resource use and resource productivity could provide valuable guidance for economic policy planning in Mexico.

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The objective of this work was to develop an easily applicable technique and a standardized protocol for high-quality post-mortem angiography. This protocol should (1) increase the radiological interpretation by decreasing artifacts due to the perfusion and by reaching a complete filling of the vascular system and (2) ease and standardize the execution of the examination. To this aim, 45 human corpses were investigated by post-mortem computed tomography (CT) angiography using different perfusion protocols, a modified heart-lung machine and a new contrast agent mixture, specifically developed for post-mortem investigations. The quality of the CT angiographies was evaluated radiologically by observing the filling of the vascular system and assessing the interpretability of the resulting images and by comparing radiological diagnoses to conventional autopsy conclusions. Post-mortem angiography yielded satisfactory results provided that the volumes of the injected contrast agent mixture were high enough to completely fill the vascular system. In order to avoid artifacts due to the post-mortem perfusion, a minimum of three angiographic phases and one native scan had to be performed. These findings were taken into account to develop a protocol for quality post-mortem CT angiography that minimizes the risk of radiological misinterpretation. The proposed protocol is easy applicable in a standardized way and yields high-quality radiologically interpretable visualization of the vascular system in post-mortem investigations.

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A principis de 2002, a la facultat de Ciències de la Comunicació de la Universitat Autònoma de Barcelona es va implantar un sistema de digitalització d'àudio, per tal de modernitzar els laboratoris de ràdio i adaptar-los a la realitat actual dels massmedia. Aquest sistema, anomenat Dalet Plus, permet produir, editar i gestionar material multimèdia relacionat amb les assignatures de ràdio impartides a la facultat. Fins ara, no existia cap aplicació que gestionés el material de cursos anteriors produït amb el sistema Dalet. L'objectiu d'aquest projecte, és desenvolupar una aplicació en entorn web, accessible a tothom, per a que alumnes, professors i tècnics puguin consultar, reproduir i recuperar, el material produït amb el sistema Dalet Plus de cursos anteriors.

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Polarization indices presented up to now have only focused their attention on the distribution of income/wealth. However, in many circumstances income is not the only relevant dimension that might be the cause of social conflict, so it is very important to have a social polarization index able to cope with alternative dimensions. In this paper we present an axiomatic characterization of one of such indices: it has been obtained as an extension of the (income) polarization measure introduced in Duclos, Esteban and Ray (2004) to a wider domain. It turns out that the axiomatic structure introduced in that paper alone is not appropriate to obtain a fully satisfactory characterization of our measure, so additional axioms are proposed. As a byproduct, we present an alternative axiomatization of the aforementioned income polarization measure.

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The algorithmic approach to data modelling has developed rapidly these last years, in particular methods based on data mining and machine learning have been used in a growing number of applications. These methods follow a data-driven methodology, aiming at providing the best possible generalization and predictive abilities instead of concentrating on the properties of the data model. One of the most successful groups of such methods is known as Support Vector algorithms. Following the fruitful developments in applying Support Vector algorithms to spatial data, this paper introduces a new extension of the traditional support vector regression (SVR) algorithm. This extension allows for the simultaneous modelling of environmental data at several spatial scales. The joint influence of environmental processes presenting different patterns at different scales is here learned automatically from data, providing the optimum mixture of short and large-scale models. The method is adaptive to the spatial scale of the data. With this advantage, it can provide efficient means to model local anomalies that may typically arise in situations at an early phase of an environmental emergency. However, the proposed approach still requires some prior knowledge on the possible existence of such short-scale patterns. This is a possible limitation of the method for its implementation in early warning systems. The purpose of this paper is to present the multi-scale SVR model and to illustrate its use with an application to the mapping of Cs137 activity given the measurements taken in the region of Briansk following the Chernobyl accident.