2,436 research outputs found

    Estudio de aprovechamiento energético en las viviendas mediante energía solar

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    Publicado em CD-ROMEn la construcción de nuevos edificios surge la idea de una construcción energéticamente eficiente. El objetivo es optimizar los recursos energéticos en nuestros hogares y para ello planteamos dos instalaciones a realizar: energía solar térmica (para producción de agua caliente sanitaria) y energía solar fotovoltaica (para generación de corriente eléctrica). En este artículo se trata de calcular el dimensionamiento de ambas instalaciones en función de la ubicación y las características de la vivienda. Este estudio plantea los modelos matemáticos de ambas instalaciones y con la ayuda de la optimización matemática resolvemos los algoritmos sujetos a unas restricciones. Como aplicación del problema vamos a analizar el caso de una vivienda unifamiliar en una zona climática definida, para así notar la importancia de los parámetros que intervienen en la caracterización de las instalaciones. El objetivo del estudio es determinar de forma rápida y aproximada la viabilidad técnica de ambas instalaciones conociendo escasos datos de partida

    The chemistry and bioactive properties behind microalgae-enriched gluten-free breads

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    This work aims to: (i) assess volatiles composition of microalgae-enriched gluten-free breads (prepared with Tetraselmis chuii, Chlorella vulgaris and Microchloropsis gaditana); (ii) report the bioaccessibility of protein and minerals after a static in vitro digestion model; (iii) understand how it affects the bioactive properties of gluten-free breads in regard to antioxidant capacity and the α-amylase inhibitory potential. Therefore, nutritional composition and bioactive properties of gluten-free breads before and after in vitro digestion model were examined. Identification of compounds responsible for the overall aroma of microalgae using GC–MS was done. There was a considerable decrease in protein and minerals available after in vitro digestion, as well as in the antioxidant potential. The overall aroma of microalgae-enriched breads was mainly due to the presence of alcohols, representing the major class of volatiles present in breads (3% to 59%), being lower for T. chuii-enriched bread. Terpenes also existed in considerable amounts especially in M. gaditana (24%) where γ-terpinene was the most abundant. Alkanoic acids were the most abundant lipophilic bioactive compounds (25%–68%), and 9,12-octadecadienoic acid was the major identified compound (13%–51%). Phytic acid is also present in all microalgae-enriched breads and may contribute to the decrease in the bioaccessibility of nutrients.info:eu-repo/semantics/publishedVersio

    Protest attitudes and stated preferences: Evidence on scale usage heterogeneity

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    We contribute to the stated preference literature by addressing scale usage heterogeneity regarding how individuals answer attitudinal questions capturing lack of trust in institutions and fairness issues. Using a latent class model, we conduct a contingent valuation study to elicit the willingness-to-pay to preserve a recreational site. We find evidence that respondents within the same class, that is, with similar preferences and attitudes, interpret the Likert scale differently when answering the attitudinal questions. We identify different patterns of scale usage heterogeneity within and across classes and associate them with individual characteristics. Our approach contributes to better a understanding of individual behavior in the presence of protest attitudes

    Identifying Nonrational Behavior in Recreation Demand Models

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    In the context of an estimated RPL (Random Parameters Logit) choice model of recreational demand for the game reserves of the KwaZulu-Natal province in South Africa, a test on the existence of an underlying rational preference structure is presented. The proposed procedure allows to identify nonrational behavior in the sample. Using two different data sets extracted from the original data base, we show that by improving the data, apparent nonrationality can be eliminated and welfare analysis may be safely conducted.N/

    Morphometric differences in the grasshopper Cornops aquaticum (Bruner, 1906) from South America and South Africa

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    The semi-aquatic grasshopper Cornops aquaticum is native to South America and inhabits lowlands from southern Mexico to Central Argentina and Uruguay. It is host-specific to aquatic plants in the genera Eichhornia and Pontederia. A quarantine population has existed in South Africa for 10 y, and it is planned to release it there as a biological control agent of water hyacinth, E. crassipes. Various studies of C. aquaticum are coordinated under HICWA (www.mpil-ploen.mpg.de). This paper compares the morphometry of the release population and 11 native populations in South America. We tested four hypotheses: 1) South African and South American populations of C. aquaticum differ in morphology; 2) the South African laboratory population is more similar to other isolated populations in South America than to nonisolated populations; 3) morphology differs across sites; 4) morphology differs with host plant. South African populations differed from continental nonisolated populations, but not from continental isolated ones. Isolated populations presented smaller individuals than nonisolated, but there was also a change in male morphology: while in nonisolated populations male wing length was similar to their body length, in isolated populations, male wings were smaller than body length. Females were larger when on Eicchornia azurea than on E. crassipes, while males presented larger wings than their body on E. azurea, and similar lengths on E. crassipes. These morphological changes may have resulted from phenotypic plasticity, selection for small size, or because of a loss of genetic diversity in quantitative traits.Fil: Adis, Joachim. Institute for Limnology; AlemaniaFil: Sperber, Carlos F. Universidade Federal de Viçosa; BrasilFil: Brede, Edward G. Institute for Limnology; AlemaniaFil: Capello, Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Franceschini, Maria Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Hill, Martin. Rhodes University; SudáfricaFil: Lhano, Marcos G. Universidade Federal de Viçosa; BrasilFil: Marques, Marinê. A;z M.. Universidade Federal de Mato Grosso; BrasilFil: Nunes, Ana L.. Muséu Paraense Emílio Goeldi; BrasilFil: Polar, Perry. CAB International; Trinidad y Tobag
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