754 resultados para why-questioning
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Examina el proceso de la renegociacion de la deuda externa y la necesidad de instaurar una logica mas compatible con los intereses de los paises latinoamericanos. Expone como condicion necesaria para lograrlo, la capacidad de los liderazgos politicos para presentar a sus pueblos las verdaderas opciones, asi como los costos y riesgos de cada una de ellas.
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Unlike correlation of classical systems, entanglement of quantum systems cannot be distributed at will: if one system A is maximally entangled with another system B, it cannot be entangled at all with a third system C. This concept, known as the monogamy of entanglement, is manifest when the entanglement of A with a pair BC can be divided as contributions of the entanglement between A and B and A and C, plus a term τABC involving genuine tripartite entanglement and so expected to be always positive. A very important measure in quantum information theory, the entanglement of formation (EOF), fails to satisfy this last requirement. Here we present the reasons for that and show a set of conditions that an arbitrary pure tripartite state must satisfy for the EOF to become a monogamous measure, i.e., for τABC≥0. The relation derived is connected to the discrepancy between quantum and classical correlations, τABC being negative whenever the quantum correlation prevails over the classical one. This result is employed to elucidate features of the distribution of entanglement during a dynamical evolution. It also helps to relate all monogamous instances of the EOF to the squashed sntanglement, an entanglement measure that is always monogamous. © 2013 American Physical Society.
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A perfect match: Silver deposition is one of the fastest electrochemical reactions, even though the Ag+ ion loses more than 5 eV solvation energy in the process. This phenomenon, an example of the enigma of metal deposition, was investigated by a combination of MD simulations, DFT, and specially developed theory. At the surface, the Ag+ ion experiences a strong interaction with the sp band of silver, which catalyzes the reaction. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Currently, the world meat trade is undergoing substantial changes as a consequence of the spread of transboundary animal diseases. These diseases have resulted in the implementation of trade embargoes applied nation-wide against infected countries, contrary to the principle of regionalization. This principle allows a country to declare part of its territory free from a given disease even though there have been outbreaks in other regions thus averting the need to suspend all exports. Its application consists in the formal recognition that a zone is disease- or pest-free. This article presents some of the disputes caused by reluctance to apply the regionalization principle in the case of the three main transboundary diseases that have affected meat trade in recent years: "mad cow disease", foot and mouth disease, and avian flu. This article analyses the positions taken by some consumer markets and the challenges that the principal exporting nations have faced when confronted with trade embargoes.
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Pós-graduação em Filosofia - FFC
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Land cover change in the Neotropics represents one of the major drivers of global environmental change. Several models have been proposed to explore future trajectories of land use and cover change, particularly in the Amazon. Despite the remarkable development of these tools, model results are still surrounded by uncertainties. None of the model projections available in the literature plausibly captured the overall trajectory of land use and cover change that has been observed in the Amazon over the last decade. In this context, this study aims to review and analyze the general structure of the land use models that have most recently been used to explore land use change in the Amazon, seeking to investigate methodological factors that could explain the divergence between the observed and projected rates, paying special attention to the land demand calculations. Based on this review, the primary limitations inherent to this type of model and the extent to which these limitations can affect the consistency of the projections will also be analyzed. Finally, we discuss potential drivers that could have influenced the recent dynamic of the land use system in the Amazon and produced the unforeseen land cover change trajectory observed in this period. In a complementary way, the primary challenges of the new generation of land use models for the Amazon are synthesized. (c) 2014 Elsevier Ltd. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Carbon nanotubes have been at the forefront of nanotechnology, leading not only to a better understanding of the basic properties of charge transport in one dimensional materials, but also to the perspective of a variety of possible applications, including highly sensitive sensors. Practical issues, however, have led to the use of bundles of nanotubes in devices, instead of isolated single nanotubes. From a theoretical perspective, the understanding of charge transport in such bundles, and how it is affected by the adsorption of molecules, has been very limited, one of the reasons being the sheer size of the calculations. A frequent option has been the extrapolation of knowledge gained from single tubes to the properties of bundles. In the present work we show that such procedure is not correct, and that there are qualitative differences in the effects caused by molecules on the charge transport in bundles versus isolated nanotubes. Using a combination of density functional theory and recursive Green's function techniques we show that the adsorption of molecules randomly distributed onto the walls of carbon nanotube bundles leads to changes in the charge density and consequently to significant alterations in the conductance even in pristine tubes. We show that this effect is driven by confinement which is not present in isolated nanotubes. Furthermore, a low concentration of dopants randomly adsorbed along a two-hundred nm long bundle drives a change in the transport regime; from ballistic to diffusive, which can account for the high sensitivity to different molecules.
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Pós-graduação em Serviço Social - FCHS
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The exposure to unethical and unprofessional behavior is thought to play a major role in the declining empathy experienced by medical students during their training. We reflect on the reasons why medical schools are tolerant of unethical behavior of faculty. First, there are barriers to reporting unprofessional behavior within medical schools including fear of retaliation and lack of mechanisms to ensure anonymity. Second, deans and directors do not want to look for unethical behavior in their colleagues. Third, most of us have learned to take disrespectful circumstances in health care institutions for granted. Fourth, the accreditation of medical schools around the world does not usually cover the processes or outcomes associated with fostering ethical behavior in students. Several initiatives promise to change that picture.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)