5,431 research outputs found

    A Political Economy Model of Regulation Explained Through Fuzzy Logics

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    The basic problem of environmental regulation involves the government trying to induce a polluter to take socially desirable actions, which ostensibly are not in the best interest of the polluter. But the government may not always be able to precisely control the polluter. To further complicate matters the government faces a complex problem of determining exactly what level of pollution is best for society. In reality the government faces pressures from consumers and polluters. There are some important lessons to gather from the analysis of current models of regulation. One is that there are many imperfect links between the legislature and the pollution-generating process. In this case regulation may be excessively costly, may result in considerable cheating, and may result in excessive pollution. Another lesson is that legislature does not necessarily act as an efficient benevolent maximizer of social well-being. The authors intend in this paper to explain the current view of political models of regulation, analysing them for their complexity, and attempt to provide a reasonable explanation of their functioning recurring to fuzzy logics. Understanding how the browns and greens interact with the legislature and regulatory agencies can to some extent explain the current environmental regulations. The fuzzy approach, intends to allow for easier understanding of these interactions, and provide an answer for more effective decision making. Keywords: Environmental Regulation, Environmental Economics, Fuzzy Logics, Models, Pollution Control, Sustainability

    Transition metal ions at the crossroads of mucosal immunity and microbial pathogenesis.

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    Transition metal ions are essential micronutrients for all living organisms. In mammals, these ions are often protein-bound and sequestered within cells, limiting their availability to microbes. Moreover, in response to infection, mammalian hosts further reduce the availability of metal nutrients by activating epithelial cells and recruiting neutrophils, both of which release metal-binding proteins with antimicrobial function. Microorganisms, in turn, have evolved sophisticated systems to overcome these limitations and acquire the metal ions essential for their growth. Here we review some of the mechanisms employed by the host and by pathogenic microorganisms to compete for transition metal ions, with a discussion of how evading "nutritional immunity" benefits pathogens. Furthermore, we provide new insights on the mechanisms of host-microbe competition for metal ions in the mucosa, particularly in the inflamed gut

    The close limit from a null point of view: the advanced solution

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    We present a characteristic algorithm for computing the perturbation of a Schwarzschild spacetime by means of solving the Teukolsky equation. We implement the algorithm as a characteristic evolution code and apply it to compute the advanced solution to a black hole collision in the close approximation. The code successfully tracks the initial burst and quasinormal decay of a black hole perturbation through 10 orders of magnitude and tracks the final power law decay through an additional 6 orders of magnitude. Determination of the advanced solution, in which ingoing radiation is absorbed by the black hole but no outgoing radiation is emitted, is the first stage of a two stage approach to determining the retarded solution, which provides the close approximation waveform with the physically appropriate boundary condition of no ingoing radiation.Comment: Revised version, published in Phys. Rev. D, 34 pages, 13 figures, RevTe
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