6,458 research outputs found

    Internet Media in Technological Risk Amplification: Plutonium on Board the Cassini-Huygens Spacecraft

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    The author discusses how the Cassini controversy demonstrates the power of the Internet, particularly listservs and Usenet groups, and how this resource offers political activists an opportunity to affect the agendas of risk management policy decision-makers

    Does the Use of Imported Intermediates Increase Productivity? Plant-Level Evidence

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    This paper examines whether importing intermediate goods improves plant performance. While addressing the issue of simultaneity of a productivity shock and decisions to import intermediates, we estimate the impact of the use of foreign intermediates on plants' productivity using plant-level Chilean manufacturing panel data. We found that the switching from being a non-importer to being an importer of foreign intermediates can improve productivity by 3.4 to 22.5 percentproductivity, imported intermediates, plant-level

    From Big Bang to Galactic Civilizations

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    Each scientific study emerges in its own particular time and marks a new step in the development of human thought.1 Big History materialized to satisfy the human need for a unified vision of our existence. It came together in the waning decades of the twentieth century, in part, as a reaction to the specialization of scholarship and education that had taken hold around the world. While this specialization had great results, it created barriers that stood in contrast to a growing unity among our global communities. These barriers were increasingly awkward to bridge, and, thus, Big History emerged as a successful new framework

    Discussion summary: Fictitious domain methods

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    Fictitious Domain methods are constructed in the following manner: Suppose a partial differential equation is to be solved on an open bounded set, Omega, in 2-D or 3-D. Let R be a rectangle domain containing the closure of Omega. The partial differential equation is first solved on R. Using the solution on R, the solution of the equation on Omega is then recovered by some procedure. The advantage of the fictitious domain method is that in many cases the solution of a partial differential equation on a rectangular region is easier to compute than on a nonrectangular region. Fictitious domain methods for solving elliptic PDEs on general regions are also very efficient when used on a parallel computer. The reason is that one can use the many domain decomposition methods that are available for solving the PDE on the fictitious rectangular region. The discussion on fictitious domain methods began with a talk by R. Glowinski in which he gave some examples of a variational approach to ficititious domain methods for solving the Helmholtz and Navier-Stokes equations

    Semiparametric topographical mixture models with symmetric errors

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    Motivated by the analysis of a Positron Emission Tomography (PET) imaging data considered in Bowen et al. (2012), we introduce a semiparametric topographical mixture model able to capture the characteristics of dichotomous shifted response-type experiments. We propose a local estimation procedure, based on the symmetry of the local noise, for the proportion and locations functions involved in the proposed model. We establish under mild conditions the minimax properties and asymptotic normality of our estimators when Monte Carlo simulations are conducted to examine their finite sample performance. Finally a statistical analysis of the PET imaging data in Bowen et al. (2012) is illustrated for the proposed method.Comment: 19 figure

    Compétitivité canadienne et libre-échange nord-américain : les trois premières années de l’ALÉ

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    Cet article tente d’établir un bilan de l’évolution des facteurs de compétitivité relative du secteur manufacturier canadien depuis l’entrée en vigueur de l’Accord de libre-échange et évalue les effets structurels qui en ont découlé pour le volume des échanges bilatéraux et multilatéraux.This paper is an attempt to monitor the economic changes that have resulted from changes in Canadian competitiveness as a result of the FTA. The sources of changes in Canadian manufacturing competitiveness and their structural effects on bilateral and multilateral trade flows are identified
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