110 research outputs found

    Urban transition and agricultural development

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    Evaluation of corporate environmental management approaches: A framework and application

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    This article proposes a framework to evaluate corporate environmental strategies. In the proposed framework, a company's environmental risks are analyzed on two dimensions, One dimension, the endogenous environmental risks, arises from the internal operations of the company. The other dimension, the exogenous environmental risks, are determined by the company's external world: its location, its ecological setting, and the demographic characteristics of the physical environment in which it operates. Four environmental management approaches are defined as a function of endogenous and exogenous environmental risks: reactive, proactive, strategic, and crisis preventive. The framework was applied in a survey of 141 company representatives in Hungary. A relationship was sought between the a priori defined environmental management approaches based on technology and location and the companies' environmental management characteristics defined by senior managers. Variables that differentiated among the four environmental management approaches were identified and ranked. The study concludes that there is a relatively well-defined relationship between the environmental risks of companies and the nature of their environmental management approaches, Implementing a strategic environmental management approach may not be the best option for all companies - although there is a growing pressure to do so

    Enhancing structure relaxations for first-principles codes: an approximate Hessian approach

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    We present a method for improving the speed of geometry relaxation by using a harmonic approximation for the interaction potential between nearest neighbor atoms to construct an initial Hessian estimate. The model is quite robust, and yields approximately a 30% or better reduction in the number of calculations compared to an optimized diagonal initialization. Convergence with this initializer approaches the speed of a converged BFGS Hessian, therefore it is close to the best that can be achieved. Hessian preconditioning is discussed, and it is found that a compromise between an average condition number and a narrow distribution in eigenvalues produces the best optimization.Comment: 9 pages, 3 figures, added references, expanded optimization sectio

    How Corporate Executives Perceive Environmental Issues

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    This article reports the results of a survey conducted in Hungary to compare the environmental perceptions of Hungarian corporate managers with those of other executives from around the world who had earlier responded to a similar survey conducted by McKinsey and Company. The results showed virtually no differences in how Hungarian managers perceived the importance of environmental challenges, but they did reveal stronger differences in perceptions between Hungarian and international respondents and among Hungarian respondents from companies in different owner

    The steady-state transcriptome of the four major life-cycle stages of Trypanosoma cruzi

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    <p>Abstract</p> <p>Background</p> <p>Chronic chagasic cardiomyopathy is a debilitating and frequently fatal outcome of human infection with the protozoan parasite, <it>Trypanosoma cruzi</it>. Microarray analysis of gene expression during the <it>T. cruzi </it>life-cycle could be a valuable means of identifying drug and vaccine targets based on their appropriate expression patterns, but results from previous microarray studies in <it>T. cruzi </it>and related kinetoplastid parasites have suggested that the transcript abundances of most genes in these organisms do not vary significantly between life-cycle stages.</p> <p>Results</p> <p>In this study, we used whole genome, oligonucleotide microarrays to globally determine the extent to which <it>T. cruzi </it>regulates mRNA relative abundances over the course of its complete life-cycle. In contrast to previous microarray studies in kinetoplastids, we observed that relative transcript abundances for over 50% of the genes detected on the <it>T. cruzi </it>microarrays were significantly regulated during the <it>T. cruzi </it>life-cycle. The significant regulation of 25 of these genes was confirmed by quantitative reverse-transcriptase PCR (qRT-PCR). The <it>T. cruzi </it>transcriptome also mirrored published protein expression data for several functional groups. Among the differentially regulated genes were members of paralog clusters, nearly 10% of which showed divergent expression patterns between cluster members.</p> <p>Conclusion</p> <p>Taken together, these data support the conclusion that transcript abundance is an important level of gene expression regulation in <it>T. cruzi</it>. Thus, microarray analysis is a valuable screening tool for identifying stage-regulated <it>T. cruzi </it>genes and metabolic pathways.</p
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