13,116 research outputs found

    Estudio y desarrollo de indicadores biológicos para evaluar el alcance espacial de vertidos procedentes de granjas marinas

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    Desarrollo de bioindicadores sensibles a los aportes de nutrientes de las granjas marinas y su aplicación a metodologías que permitan de finir sus áreas de influencia y seleccionar las zonas aptas para la acuicultura en aguas abiertas bajo criterios ecológicos

    Role of 5 α -dihydrotestosterone in testicular development of gilthead seabream following finasteride administration

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    In teleosts, spermatogenesis is regulated by pituitary gonadotropins and sex steroids. 5α-dihydrotestosterone (DHT), derived from testosterone (T) through the action of 5α-reductase, has recently been suggested to play a physiologically important role in some fish species. In this study, gilthead seabream, Sparus aurata L., males received an implant of 1μg T/g body mass (bm) or vehicle alone and, 7 days later, 1 mg finasteride (FIN, an inhibitor of 5α-reductase)/kg bm or vehicle. Serum levels of T, 11-ketotestosterone (11KT), DHT and 17β-estradiol (E2), and the mRNA levels of the main enzymes involved in their synthesis, were analysed. T promoted a transient increase in the serum levels of T, 11KT and E2 but a decrease in those of DHT at day 15 following T injection, in accordance with the up-regulation of mRNA levels of the enzymes involved in T transformation to 11KT (coding genes: cyp11b1 and hsd11b) and the down-regulation of mRNA levels of the enzyme responsible for T transformation to DHT (coding gene:srd5a). Interestingly, a similar effect was observed when FIN was in- jected. However, when fish were injected with T and FIN successively (T + FIN), control levels were not re-covered at the end of the experimental period (28 days). DHT seems to regulate E2 serum levels via the down-regulation of mRNA levels of aromatase (coding gene:cyp19a1a), which is needed for the transformation of T into E2. The testis histology, together with the proliferative rates recorded upon T, FIN or T + FIN treatment, suggests that DHT is involved in the onset of the meiotic phase of spermatogenesis.Versión del edito

    Correlated hopping of bosonic atoms induced by optical lattices

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    In this work we analyze a particular setup with ultracold atoms trapped in state-dependent lattices. We show that any asymmetry in the contact interaction translates into one of two classes of correlated hopping. After deriving the effective lattice Hamiltonian for the atoms, we obtain analytically and numerically the different phases and quantum phase transitions. We find for weak correlated hopping both Mott insulators and charge density waves, while for stronger correlated hopping the system transitions into a pair superfluid. We demonstrate that this phase exists for a wide range of interaction asymmetries and has interesting correlation properties that differentiate it from an ordinary atomic Bose-Einstein condensate.Comment: 24 pages with 9 figures, to appear in New Journal of Physic

    A Model-Driven Approach for Business Process Management

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    The Business Process Management is a common mechanism recommended by a high number of standards for the management of companies and organizations. In software companies this practice is every day more accepted and companies have to assume it, if they want to be competitive. However, the effective definition of these processes and mainly their maintenance and execution are not always easy tasks. This paper presents an approach based on the Model-Driven paradigm for Business Process Management in software companies. This solution offers a suitable mechanism that was implemented successfully in different companies with a tool case named NDTQ-Framework.Ministerio de Educación y Ciencia TIN2010-20057-C03-02Junta de Andalucía TIC-578

    Software Process Management: A Model- Based Approach

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    Business processes constitute one major asset in an organization and software businesses are not an exception. Processes defi nition, maintenance, and management are key aspects to control and defi ne how to build software systems up and also to support decision-making. In this paper, a model-based approach is proposed to facilitate these processes. Thus, a global environment for business processes in software development is presented. The fi nal results are illustrated through the NDTQ-Framework, a solution based on this approach that is currently being used in software development organizations.Ministerio de Ciencia e Innovación TIN2010-20057-C03-02Ministerio de Ciencia e Innovación TIN 2010-12312-EJunta de Andalucía TIC-578

    Characterization of terrestrial hot particles from the Palomares accident using destructive and non-destructive analytical techniques

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    Several radioactive particles from the Palomares area have been analyzed with the nuclearmicroprobe of the National Accelerator Centre (CNA) in Seville exploring the advantages of combining -PIXE using a 5.5 MeV4He beam with conventional -PIXE analysis using 3 MeV protons. Themeasurements performed with the -particles are more sensitive to the sample surface, while the resultscollected with protons are indicative of the average composition of the hot particle. In this way, importantinformation about the depth distribution of Pu and U in the particles has been obtained. In addition, theparticles have been analyzed by SEM (EDX) and one of them has been sacrificed for the determinationof its U and Pu isotopic composition by ICP-MS and -spectrometry, being gained in this way importantinformation about the composition of the weapons involved in the Palomares accident.Junta de Andalucía Excellence Project TU-DRAMA (Ultra-sensitive techniques for radionuclides determination in environmental materials

    Seasonal dynamic factor analysis and bootstrap inference : application to electricity market forecasting

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    Year-ahead forecasting of electricity prices is an important issue in the current context of electricity markets. Nevertheless, only one-day-ahead forecasting is commonly tackled up in previous published works. Moreover, methodology developed for the short-term does not work properly for long-term forecasting. In this paper we provide a seasonal extension of the Non-Stationary Dynamic Factor Analysis, to deal with the interesting problem (both from the economic and engineering point of view) of long term forecasting of electricity prices. Seasonal Dynamic Factor Analysis (SeaDFA) allows to deal with dimensionality reduction in vectors of time series, in such a way that extracts common and specific components. Furthermore, common factors are able to capture not only regular dynamics (stationary or not) but also seasonal one, by means of common factors following a multiplicative seasonal VARIMA(p,d,q)×(P,D,Q)s model. Besides, a bootstrap procedure is proposed to be able to make inference on all the parameters involved in the model. A bootstrap scheme developed for forecasting includes uncertainty due to parameter estimation, allowing to enhance the coverage of forecast confidence intervals. Concerning the innovative and challenging application provided, bootstrap procedure developed allows to calculate not only point forecasts but also forecasting intervals for electricity prices

    Juan Ramón Jiménez y su entorno social y cultural: de la correspondencia con León Sánchez Cuesta (1927-1956)

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    Este artículo profundiza en el entorno social y cultural de Juan Ramón Jiménez a través de su relación con León Sánchez Cuesta, conocido como el “librero de la generación del 27”. Para ello revisamos diversas fuentes bibliográfi cas, especialmente la correspondencia inédita que el librero dirigió al poeta y de la cual se reproducen en el artículo dos cartas. Sánchez Cuesta fue amigo personal, depositario exclusivo de la obra de Juan Ramón Jiménez entre 1925 y 1933, aproximadamente, difusor y distribuidor de su obra y uno de sus principales suministradores de libros. El librero también jugó un papel importante como mediador en las disputas entre Juan Ramón Jiménez y algunos poetas de la “generación del 27”. Sánchez Cuesta es considerado una figura clave en el entorno de Juan Ramón Jiménez y su correspondencia nos permite indagar en el entorno social y cultural y los hábitos de lectura del poeta de Moguer.This article analyzes the social and cultural context of Juan Ramón Jiménez through his relationship with León Sánchez Cuesta, also known as “the librarian of the generation of 27”. For this purpose we review different bibliographic sources, including the unpublished correspondence between Sánchez Cuesta and Juan Ramón Jiménez. Two of these letters are included in this article. Sánchez Cuesta was a friend and sole distributor of the works of Juan Ramón Jiménez during (approximately) the years 1925-1933. He played an important role spreading the work of Juan Ramón and providing him with reading materials. Sánchez Cuesta also played an important mediator role in some disputes between Juan Ramón and some poets of the “generation of ‘27”. Sánchez Cuesta is a key figure in the life of Juan Ramón Jiménez and his correspondence increases our understanding of both the social and cultural context and the reading habits of Juan Ramón Jiménez
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