8,806 research outputs found

    Suddenly last summer: how the tourist tsunami hit Lisbon

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    En el presente artículo fijamos nuestra atención en la capital de Portugal, Lisboa, y su reciente proceso de turistificación, que ha forzado a una revisión colectiva de la identidad de la ciudad y sus narrativas patrimoniales, para encajar los crecientes contrastes entre marginalidad y centralidad, circulación y calma, abandono y atención pública, indigencia y afluencia, spleen y euforia. Después de introducir nuestro foco teórico en el problema de los “comunales urbanos” y de presentar nuestra metodología cualitativa, pasamos a describir el proceso histórico que ha conducido a la transformación de Lisboa: desde el mega-evento de la Expo’98 cuando Lisboa era todavía un destino turístico periférico, hasta la presente economía urbana, especializada en el turismo y los servicios. Vamos a centrarnos especialmente en los proyectos y políticas implantadas “desde arriba” durante aquellos años y en la crisis financiera de 2008, usada para liberalizar varios aspectos de la economía.In this paper, we focus our attention in Portugal’s capital city, Lisbon, and in the recent process of its touristification, which is forcing a collective revision of the city’s identity and its patrimonial narratives, to make sense of the growing contrasts between marginality and centrality, circulation and calm, abandonment and limelight, indigence and affluence, spleen and euphoria. After introducing our theoretical focus on the problem of “urban commons” and the qualitative methodology used in the article, we describe the historical process that led to the transformation of Lisbon: from the Expo’98 megaevent when Lisbon was a peripheral tourism destiny, to the present urban economy that is specialized in tourism and services. We will focus especially in the top-down projects and policies developed during those years and the use of 2008 financial crisis to liberalize many aspects of economy

    Lithium solvation in dimethyl sulfoxide-acetonitrile mixtures

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    We present molecular dynamics simulation results pertaining to the solvation of Li+ in dimethyl sulfoxide-acetonitrile binary mixtures. The results are potentially relevant in the design of Li-air batteries that rely on aprotic mixtures as solvent media. To analyze effects derived from differences in ionic size and charge sign, the solvation of Li+ is compared to the ones observed for infinitely diluted K+ and Cl− species, in similar solutions. At all compositions, the cations are preferentially solvated by dimethyl sulfoxide. Contrasting, the first solvation shell of Cl− shows a gradual modification in its composition, which varies linearly with the global concentrations of the two solvents in the mixtures. Moreover, the energetics of the solvation, described in terms of the corresponding solute-solvent coupling, presents a clear non-ideal concentration dependence. Similar nonlinear trends were found for the stabilization of different ionic species in solution, compared to the ones exhibited by their electrically neutral counterparts. These tendencies account for the characteristics of the free energy associated to the stabilization of Li+Cl−, contact-ion-pairs in these solutions. Ionic transport is also analyzed. Dynamical results show concentration trends similar to those recently obtained from direct experimental measurements.Fil: Semino, Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Zaldivar, Gervasio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Calvo, Ernesto Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Laria, Daniel Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Comisión Nacional de Energía Atómica; Argentin

    Teoría de juegos y subastas en economía y empresa

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    Se explica el funcionamiento de las subastas, centrándose en última instancia en el mecanismo de las subastas de las letras del tesoro del Banco de EspañaDepartamento de Economía AplicadaGrado en Economí

    El corral de San Guisán : leyenda leonesa (tradición popular)

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    Precede al tít.: Dos de Mayo de 1908, 1er. Centenario de la Independencia españolaCopia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-201

    Heuristic usability evaluation on games: a modular approach

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    Heuristic evaluation is the preferred method to assess usability in games when experts conduct this evaluation. Many heuristics guidelines have been proposed attending to specificities of games but they only focus on specific subsets of games or platforms. In fact, to date the most used guideline to evaluate games usability is still Nielsen’s proposal, which is focused on generic software. As a result, most evaluations do not cover important aspects in games such as mobility, multiplayer interactions, enjoyability and playability, etc. To promote the usage of new heuristics adapted to different game and platform aspects we propose a modular approach based on the classification of existing game heuristics using metadata and a tool, MUSE (Meta-heUristics uSability Evaluation tool) for games, which allows a rebuild of heuristic guidelines based on metadata selection in order to obtain a customized list for every real evaluation case. The usage of these new rebuilt heuristic guidelines allows an explicit attendance to a wide range of usability aspects in games and a better detection of usability issues. We preliminarily evaluate MUSE with an analysis of two different games, using both the Nielsen’s heuristics and the customized heuristic lists generated by our tool.Unión Europea PI055-15/E0

    Negative modulation of the GABAAρ1 receptor function by l-cysteine

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    l-Cysteine is an endogenous sulfur-containing amino acid with multiple and varied roles in the central nervous system, including neuroprotection and the maintenance of the redox balance. However, it was also suggested as an excitotoxic agent implicated in the pathogenesis of neurological disorders such as Parkinson′s and Alzheimer′s disease. l-Cysteine can modulate the activity of ionic channels, including voltage-gated calcium channels and glutamatergic NMDA receptors, whereas its effects on GABAergic neurotransmission had not been studied before. In the present work, we analyzed the effects of l-cysteine on responses mediated by homomeric GABAAρ1 receptors, which are known for mediating tonic γ-aminobutyric acid (GABA) responses in retinal neurons. GABAAρ1 receptors were expressed in Xenopus laevis oocytes and GABA-evoked chloride currents recorded by two-electrode voltage-clamp in the presence or absence of l-cysteine. l-Cysteine antagonized GABAAρ1 receptor-mediated responses; inhibition was dose-dependent, reversible, voltage independent, and susceptible to GABA concentration. Concentration-response curves for GABA were shifted to the right in the presence of l-cysteine without a substantial change in the maximal response. l-Cysteine inhibition was insensitive to chemical protection of the sulfhydryl groups of the ρ1 subunits by the irreversible alkylating agent N-ethyl maleimide. Our results suggest that redox modulation is not involved during l-cysteine actions and that l-cysteine might be acting as a competitive antagonist of the GABAAρ1 receptors. (Figure presented.).Fil: Beltrán González, Andrea Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Vicentini, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Calvo, Daniel Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin

    The Effect of the Number of Lending Banks on the Liquidity Constraints of Firms: Evidence From a Quasi-Experiment

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    We empirically explore whether firms have a target for the number of banks from which they borrow, and whether having multiple bank relationships has an impact on firms’ liquidity situation. A bank merger in Chile provides a quasi-experiment as it constitutes an exogenous reduction in the number of lenders for firms that were previously borrowing from both merging banks. We find that a significant percentage of firms whose number of bank relationships was reduced by the merger regain their original number of lenders. In particular, firms whose number of bank lending relationships was reduced from two to one as a result of the merger have a 23% higher probability of adding a new bank lending relationship in the five years following the merger than similar firms unaffected by the merger. Overall, we find that a reduction in firms’ number of bank lenders resulting from the merger reduced firms’ access to credit. In particular, a reduction from two to one bank lending relationships generated, on average, a 14.4% decrease in loan size for the affected companies compared to firms unaffected by the merger.

    Allosteric modulation of retinal GABA receptors by ascorbic acid

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    Ionotropic GABA receptors (GABAA and GABAC) belong to the Cys-loop receptor family of ligand-gated ion channels. GABAC receptors are highly expressed in the retina, mainly localized at the axon terminals of bipolar cells. Ascorbic acid, an endogenous redox agent, modulates the function of diverse proteins, and basal levels of ascorbic acid in the retina are very high. However, the effect of ascorbic acid on retinal GABA receptors has not been studied. Here we show that the function of GABAC and GABAA receptors is regulated by ascorbic acid. Patch-clamp recordings from bipolar cell terminals in goldfish retinal slices revealed that GABAC receptor-mediated currents activated by tonic background levels of extracellular GABA, and GABAC currents elicited by local GABA puffs, are both significantly enhanced by ascorbic acid. In addition, a significant rundown of GABA puff-evoked currents was observed in the absence of ascorbic acid. GABA-evoked Cl- currents mediated by homomeric ρ1 GABAC receptors expressed in Xenopus laevis oocytes were also potentiated by ascorbic acid in a concentration-dependent, stereo-specific, reversible, and voltage-independent manner. Studies involving the chemical modification of sulfhydryl groups showed that the two Cys-loop cysteines and histidine 141, all located in the ρ1 subunit extracellular domain, each play a key role in the modulation of GABAC receptors by ascorbic acid. Additionally, we show that retinal GABAA IPSCs and heterologously expressed GABAA receptor currents are similarly augmented by ascorbic acid. Our results suggest that ascorbic acid may act as an endogenous agent capable of potentiating GABAergic neurotransmission in the CNS.Fil: Calero, Cecilia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Vickers, Evan. Oregon Health and Science University; Estados UnidosFil: Cid, Gustavo Moraga. Universidad de Concepción; ChileFil: Aguayo, Luis G.. Universidad de Concepción; ChileFil: von Gersdorff, Henrique. Oregon Health and Science University; Estados UnidosFil: Calvo, Daniel Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin
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