931 resultados para Semiarid. Cyanobacteria. Phytoplankton. Cyanotoxins. Scientific dissemination


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The Centre de Supercomputació de Catalunya (CESCA) together with the Consorci de Biblioteques Universitàries de Catalunya (CBUC) started in 1999 a cooperative repository, named TDR, to file in digital format the full-text of the read thesis at the universities of our country to spread them worldwide in open access preserving the intellectual copyright of the authors. This became operational in 2001 and today it is a service fully consolidated not only among the Catalan universities, but also used by other Spanish universities. Since then, there are four additional cooperative repositories which have been created: RECERCAT, for research papers; RACO, for scientific, cultural and erudite Catalan magazines; PADICAT, for archiving Catalan web sites; and MDC, for Catalan digital collections of pictures, maps, posters, old magazines... These five repositories have some common characteristics: they are open access, that is, they are accessible on the internet for free; they mostly comply with the Open Archive Initiative interoperability protocol for facilitating the efficient dissemination of content; and they have been built in a cooperative manner so that it is easy to adopt common procedures and to share the repository developing and managing costs, it permits more visibility of the indexed documents throughout the search engines, and a better provision for long-term preservation can be made. In this paper we present the common policy established for the Catalan cooperative repositories, we describe the five of them briefly, and we comment on the results obtained of our 6-year experience since the first one became operational.

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Aquest article se centra en les implicacions de la difusió electrònica per al sistema de publicació de revistes basat en la revisió per parells [peer-reviewed]. Per donar sentit a un assumpte tan complex, és de molt ajut mirar-s'ho des de la perspectiva dels orígens del sistema i de les seves tres funcions nuclears: el rànquing en la recerca, facilitar la comunicació interactiva entre els estudiosos i crear un arxiu global del coneixement científic. Cadascuna d’aquestes funcions principals té requeriments diferents que, en certa mesura, se sobreposen però que també entren, d'alguna manera, en conflicte. Internet obre la possibilitat de desenvolupar una varietat de models distints de comunicació científica modulant la intensitat de cadascun d'aquests tres rols que les revistes en paper han desenvolupat i, possiblement, d'altres funcions que no eren ni tan sols imaginables abans del desenvolupament de les xarxes electròniques d'abast planetari. Les implicacions de la distribució electrònica per a la propietat i accés a la literatura científica són profundes i tendeixen a agreujar la ja seriosa crisi dels preus de les revistes que està frenant l'accés a la informació científica. La comunitat d'estudiosos, que és autora del material que aquestes publicacions contenen i, al mateix temps, n'és el principal consumidor, està en possessió de la clau per a solucionar aquesta crisi tot permetent a Internet ser un vehicle que faciliti la difusió d’una recerca finançada des del sector públic en comptes de crear una situació de propietat privada d'aquesta recerca.

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Cette thèse examine la circulation et l'intégration des informations scientifiques dans la pensée quotidienne d'après la théorie des représentations sociales (TRS). En tant qu'alternative aux approches traditionnelles de la communication de la science, les transformations survenant entre le discours scientifique et le discours de sens commun sont considérées comme adaptatives. Deux études sur la circulation des informations dans les media (études 1 et 2) montrent des variations dans les thèmes de discours exposés aux profanes, et parmi les discours de ceux-ci, en fonction de différentes sources. Ensuite, le processus d'ancrage dans le positionnement préalable envers la science est étudié, pour l'explication qu'il fournit de la réception et de la transmission d'informations scientifiques dans le sens commun. Les effets d'ancrage dans les attitudes et croyances préexistants sont reportés dans différents contextes de circulation des informations scientifiques (études 3 à 7), incluant des études de type corrélationnel, experimental et de terrain. Globalement, cette thèse procure des arguments en faveur de la pertinence de la TRS pour la recherche sur la communication de la science, et suggère des développements théoriques et méthodologiques pour ces deux domaines de recherche. Drawing on the social representations theory (SRT), this thesis examines the circulation and integration of scientific information into everyday thinking. As an alternative to the traditional approaches of science communication, it considers transformations between scientific and common-sense discourses as adaptive. Two studies, focused on the spreading of information into the media (Studies 1 and 2), show variations in the themes of discourses introduced to laypersons and in the themes among laypersons' discourses, according to different sources. Anchoring in prior positioning toward science is then studied for the explanation it provides on the reception and transmission of scientific information into common sense. Anchoring effects in prior attitudes and beliefs are reported in different contexts of circulation of scientific information (Studies 3 to 7) by using results from correlational, field, and experimental studies. Overall, this thesis provides arguments for the relevance of SRT in science communication research and suggests theoretical and methodological developments for both domains of research.

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Projecte de recerca elaborat a partir d’una estada a la Napier University, Gran Bretanya, des d’octubre del 2006 a febrer del 2007. Els ecosistemes marins costaners són sistemes complexos, tant pel que fa a l’estructura de les comunitats que hi viuen com per la seva dinàmica, amb processos que impliquen múltiples escales d’espai i de temps. Aquesta complexitat natural s’ha incrementat al llarg de les darreres dècades com a conseqüència directa del creixement urbà al litoral. L’augment de població a les zones costaneres ha comportat no només un augment generalitzat en l’aport de nutrients inorgànics al mar, sinó també una forta intervenció sobre la línia de costa –construcció de ports, dics- i canvis en el moviment de les masses d’aigua. En aquest context, la interacció entre els factors turbulència-nutrients a la zona costanera pot ser clau per a millorar la nostra comprensió sobre el funcionament dels sistemes planctònics i, en darrer terme, per a derivar-ne mesures de gestió. A diferència de treballs experimentals previs, que adrecen els efectes de la turbulència i/o els nutrients sobre grups específics de plàncton, per avaluar la resposta conjunta de la comunitat necessitem paràmetres integradors, que relacionin diversos processos i donin una idea general de l’estat i funcionament de l’ecosistema. Durant l’estada de recerca alguns dels algoritmes que es fan servir per la costa escocesa van reformular-se i recalcular-se amb dades de la Mediterrània (dades procedents de la badia de Blanes i de la costa de Barcelona). Els resultats mostren una capacitat de resposta molt ràpida del plàncton als increments de nutrients, una variabilitat anual marcada (quant a diversitat d’organismes planctònics) i apunten el fòsfor com a principal limitant del creixement dels organismes en aquesta zona de la Mediterrània.

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This contribution aims at exploring the significance of the new generation of UNESCO conventions for the recognition of higher education qualifications. It discusses three possible scenarios and links them to the empirical findings of a study that compares the enabling conditions of the first generation of recognition conventions established in the 1970s and 1980s with the ones establishing the second generation today. Taking an interdisciplinary approach, the paper argues that the changes illustrate a more general shift in the architecture of the global order and highlights a new role of UNESCO.

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Report for the scientific sojourn carried out at the University of New South Wales from February to June the 2007. Two different biogeochemical models are coupled to a three dimensional configuration of the Princeton Ocean Model (POM) for the Northwestern Mediterranean Sea (Ahumada and Cruzado, 2007). The first biogeochemical model (BLANES) is the three-dimensional version of the model described by Bahamon and Cruzado (2003) and computes the nitrogen fluxes through six compartments using semi-empirical descriptions of biological processes. The second biogeochemical model (BIOMEC) is the biomechanical NPZD model described in Baird et al. (2004), which uses a combination of physiological and physical descriptions to quantify the rates of planktonic interactions. Physical descriptions include, for example, the diffusion of nutrients to phytoplankton cells and the encounter rate of predators and prey. The link between physical and biogeochemical processes in both models is expressed by the advection-diffusion of the non-conservative tracers. The similarities in the mathematical formulation of the biogeochemical processes in the two models are exploited to determine the parameter set for the biomechanical model that best fits the parameter set used in the first model. Three years of integration have been carried out for each model to reach the so called perpetual year run for biogeochemical conditions. Outputs from both models are averaged monthly and then compared to remote sensing images obtained from sensor MERIS for chlorophyll.

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B cells are the primary targets of infection for mouse mammary tumor virus (MMTV). However, for productive retroviral infection, T cell stimulation through the virally-encoded superantigen (SAG) is necessary. It activates B cells and leads to cell division and differentiation. To characterize the role of B cell differentiation for the MMTV life cycle, we studied the course of infection in transgenic mice deficient for CD28/CTLA4-B7 interactions (mCTLA4-H gamma 1 transgenic mice). B cell infection occurred in CTLA4-H gamma 1 transgenic mice as integrated proviral DNA could be detected in draining lymph node cells early after infection by polymerase chain reaction analysis. In mice expressing I-E, B cells were able to present the viral SAG efficiently to V beta 6+ T cells. These cells expanded specifically and were triggered to express the activation marker CD69. Further stages of progression of infection appeared to be defective. Kinetics experiments indicated that T and B cell stimulation stopped more rapidly than in control mice. B cells acquired an activated CD69+ phenotype, were induced to produce IgM but only partially switched to IgG secretion. Finally, the dissemination of infected cells to other lymph nodes and spleen was reduced and the peripheral deletion of V beta 6+ T cells was minimal. In contrast, in mice lacking I-E, T cell stimulation was also impaired and B cell activation undetectable. These data implicate B7-dependent cellular interactions for superantigenic T cell stimulation by low-affinity TCR ligands and suggest a role of B cell differentiation in viral dissemination and peripheral T cell deletion.

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This note reviews the political-scientific literature on European competition policy (ECP) in the 2000s. Based on a data set extracted from four well-known journals, and using an upfront methodology and explicit criteria, it analyzes the literature both quantitatively and qualitatively. On the quantitative side, it shows that, although a few sub-policy areas are still neglected, ECP is not the under-researched policy it used to be. On the qualitative side, the literature has greatly improved since the 1990s: Almost all articles now present a clear research question, and most advance specific theoretical claims/hypotheses. Yet, improvements can be made on research design, statistical testing, and, above all, state-of-the-art theorizing (e.g. in the game-theoretical treatment of delegation problems). Indeed, it is paradoxical that ECP specialists do not pay more attention to theoretical questions which are so central to the actual policy area they study.

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Gout is the most common form of inflammatory arthritis in the elderly. In the last two decades, both hyperuricemia and gout have increased markedly and similar trends in the epidemiology of the metabolic syndrome have been observed. Recent studies provide new insights into the transporters that handle uric acid in the kidney as well as possible links between these transporters, hyperuricemia, and hypertension. The treatment of established hyperuricemia has also seen new developments. Febuxostat and PEG-uricase are two novel treatments that have been evaluated and shown to be highly effective in the management of hyperuricemia, thus enlarging the therapeutic options available to lower uric acid levels. Monosodium urate (MSU) crystals are potent inducers of inflammation. Within the joint, they trigger a local inflammatory reaction, neutrophil recruitment, and the production of pro-inflammatory cytokines as well as other inflammatory mediators. Experimentally, the uptake of MSU crystals by monocytes involves interactions with components of the innate immune system, namely Toll-like receptor (TLR)-2, TLR-4, and CD14. Intracellularly, MSU crystals activate multiple processes that lead to the formation of the NALP-3 (NACHT, LRR, and pyrin domain-containing-3) inflammasome complex that in turn processes pro-interleukin (IL)-1 to yield mature IL-1 beta, which is then secreted. The inflammatory effects of MSU are IL-1-dependent and can be blocked by IL-1 inhibitors. These advances in the understanding of hyperuricemia and gout provide new therapeutic targets for the future.