28,014 research outputs found

    Comparing Exchange Market Pressure in West and Southern African Countries

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    We compare the performance of Cape Verde and Mozambique concerning financial credibility as measured by Exchange Market Pressure, an institutional feature that has often been overlooked in the literature as a relevant institution for economies. Drawing on previous research by Macedo et al. (2009), we expand their analysis and, using several definitions of “financial credibility”, all related to different angles on Exchange Market Pressure indices, we conclude that - against reasonable benchmarks in their respective regions - financial credibility has been very good for Cape Verde and fairly good for Mozambique. JEL codes: C22, E44, F31, F33Exchange Rate Regime, Exchange Market Pressure, EGARCH

    Analytical study of tunneling times in flat histogram Monte Carlo

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    We present a model for the dynamics in energy space of multicanonical simulation methods that lends itself to a rather complete analytic characterization. The dynamics is completely determined by the density of states. In the \pm J 2D spin glass the transitions between the ground state level and the first excited one control the long time dynamics. We are able to calculate the distribution of tunneling times and relate it to the equilibration time of a starting probability distribution. In this model, and possibly in any model in which entering and exiting regions with low density of states are the slowest processes in the simulations, tunneling time can be much larger (by a factor of O(N)) than the equilibration time of the probability distribution. We find that these features also hold for the energy projection of single spin flip dynamics.Comment: 7 pages, 4 figures, published in Europhysics Letters (2005

    Big Data as a Technology-to-think-with for Scientific Literacy

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    This research aimed to identify indications of scientific literacy resulting from a didactic and investigative interaction with Google Trends Big Data software by first-year students from a high-school in Novo Hamburgo, Southern Brazil. Both teaching strategies and research interpretations lie on four theoretical backgrounds. Firstly, Bunge's epistemology, which provides a thorough characterization of Science that was central to our study. Secondly, the conceptual framework of scientific literacy of Fives et al. that makes our teaching focus precise and concise, as well as supports one of our methodological tool: the SLA (scientific literacy assessment). Thirdly, the "crowdledge" construct from dos Santos, which gives meaning to our study when as it makes the development of scientific literacy itself versatile for paying attention on sociotechnological and epistemological contemporary phenomena. Finally, the learning principles from Papert's Constructionism inspired our educational activities. Our educational actions consisted of students, divided into two classes, investigating phenomena chose by them. A triangulation process to integrate quantitative and qualitative methods on the assessments results was done. The experimental design consisted in post-tests only and the experimental variable was the way of access to the world. The experimental group interacted with the world using analyses of temporal and regional plots of interest of terms or topics searched on Google. The control class did 'placebo' interactions with the world through on-site observations of bryophytes, fungus or whatever in the schoolyard. As general results of our research, a constructionist environment based on Big Data analysis showed itself as a richer strategy to develop scientific literacy, compared to a free schoolyard exploration.Comment: 23 pages, 2 figures, 8 table

    Deformation and rigidity results for the 2k-Ricci tensor and the 2k-Gauss-Bonnet curvature

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    We present several deformation and rigidity results within the classes of closed Riemannian manifolds which either are 2k2k-Einstein (in the sense that their 2k2k-Ricci tensor is constant) or have constant 2k2k-Gauss-Bonnet curvature. The results hold for a family of manifolds containing all non-flat space forms and the main ingredients in the proofs are explicit formulae for the linearizations of the above invariants obtained by means of the formalism of double forms.Comment: 30 pages; no figure

    Induced pluripotent stem cells, a giant leap for mankind therapeutic applications

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    Induced pluripotent stem cells (iPSC) technology has propelled the field of stem cells biology, providing new cells to explore the molecular mechanisms of pluripotency, cancer biology and aging. A major advantage of human iPSC, compared to the pluripotent embryonic stem cells, is that they can be generated from virtually any embryonic or adult somatic cell type without destruction of human blastocysts. In addition, iPSC can be generated from somatic cells harvested from normal individuals or patients, and used as a cellular tool to unravel mechanisms of human development and to model diseases in a manner not possible before. Besides these fundamental aspects of human biology and physiology that are revealed using iPSC or iPSC-derived cells, these cells hold an immense potential for cell-based therapies, and for the discovery of new or personalized pharmacological treatments for many disorders. Here, we review some of the current challenges and concerns about iPSC technology. We introduce the potential held by iPSC for research and development of novel health-related applications. We briefly present the efforts made by the scientific and clinical communities to create the necessary guidelines and regulations to achieve the highest quality standards in the procedures for iPSC generation, characterization and long-term preservation. Finally, we present some of the audacious and pioneer clinical trials in progress with iPSC-derived cells.info:eu-repo/semantics/publishedVersio

    Evidence that the degree of band 3 phosphorylation modulates human erythrocytes nitric oxide efflux – in vitro model of hyperfibrinogenemia

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    © 2011 – IOS Press and the authors. All rights reservedRecent evidence has shown that plasma fibrinogen, a major cardiovascular risk factor, interacts with the erythrocyte membrane and acts to influence blood flow via erythrocyte nitric oxide (NO) modulation. In the present pioneer in-vitro study, whole blood samples were harvested from healthy subjects and aliquots were incubated in the absence (control aliquots) and presence of fibrinogen at different degrees of band 3 phosphorylation, and the levels of NO, nitrite, nitrate and S-nitroglutathione (GSNO) were determined. Hyperfibrinogenemia interferes with erythrocyte NO mobilization without changing its efflux in a way that seems to be dependent of the degree of band 3 phosphorylation. In presence of higher fibrinogen concentrations the NO efflux is reinforced when band 3 is phosphorylated (p < 0.001). Higher levels of nitrite, nitrate and GSNO were documented (p < 0.05). However, the mechanisms by which fibrinogen signalling modulates erythrocyte function remain to be clarified and are currently under study. These conditions may be considered an approach to be followed in blood storage for transfusions.This study was supported by grants from the FCT - Fundação para a Ciência e a Tecnologia (project reference PTDC/SAU-OSM/73449/2006
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