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121.
Polybrominated diphenyl ether in sewage sludge in Germany   总被引:2,自引:0,他引:2  
Knoth W  Mann W  Meyer R  Nebhuth J 《Chemosphere》2007,67(9):1831-1837
Sewage sludge samples from 11 municipal waste water treatment plants in Germany were collected from March 2002 to June 2003. Total Tri- to HpBDE concentrations (sum of significant congeners BDE 28, 47, 99, 153, 154 and 183) ranged from 12.5 to 288 (median 108) and DeBDE (BDE 209) concentrations from 97.1 to 2217 (median 256) ng/gd.m. BDE 209 dominated the congener profile. A significant change of the Tri- to HpBDE congener profile (% of total BDE 28, 47, 99, 153, 154, 183 without 209) in sludge from different stages of the waste water treatment process (primary sludge, secondary excess sludge and (dewatered) digested sludge), indicating a degradation of DeBDE to these congeners, was not observed.  相似文献   
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The Noise Control Act of 1972, passed by the U. S. Congress, established the Office of Noise Abatement and Control within the U. S. Environmental Protection Agency. The following discussion presents the background of this legislation, a general conceptual approach to implementing the legislation, and the practical implementation of that legislation to date by the Office of Noise Abatement and Control (ONAC).  相似文献   
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On the basis of the literature of open systems and team diversity, we present a new dynamic team diversity theory that explains the effect of change in team diversity on team functioning and performance in the context of dynamic team composition. Building upon the conceptualization of teams as open systems, we describe the enlargement and decline of team variety, separation, and disparity through member addition, subtraction, and substitution. Then, focusing on diversity enlargement, we theorize the contemporaneous and lasting effects of team diversity change on team performance change and on team processes and states leading to them. Dynamic team diversity theory expands the focus of team diversity research from teams' being more diverse than others to teams' becoming more diverse than before. It aims to advance team diversity research to be better aligned with the organizational reality of dynamic team composition. We also discuss methodological considerations in subsequent empirical testing of the theory and highlight how the theory and future research may help to guide organizational practice in recomposing work teams.  相似文献   
124.
In this paper, we review the growing literature on perceived diversity in teams. We aim to clarify the construct of perceived diversity and organize the findings in this emergent line of research. To do so, we develop a framework integrating research emerging on perceived diversity from across several different research fields. We propose that the nature of perceived diversity and its effects can be best understood by identifying the focal point of the diversity perceptions being studied: perceptions of self‐to‐team dissimilarity, of subgroup splits, and of group heterogeneity. Our review concludes that perceived self‐to‐team dissimilarity and perceived subgroup splits mostly have been linked to negative effects for individuals and groups, whereas perceived group heterogeneity has been shown to exert both positive and negative effects on group outcomes. Our review also draws attention to the problem that research on perceived diversity varies not only in definitions and conceptualizations, but also in the methodological approaches towards operationalizing perceived diversity. We conclude by discussing potential areas for future research. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
125.
The late-Paleozoic Uralides represent one of the largest lode-gold metallogenic provinces in the world. In the southern Urals, gold distribution is heterogeneous and is confined mainly to two tectonostratigraphic zones, namely the Main Uralian fault and the East Uralian zone. The important lode-gold districts within and in the immediate hangingwall of the first-order crustal suture of the Main Uralian fault are characterized by a complex tectonic history of earlier compressional tectonics involving thrusting, folding and reverse faulting and later transcurrent shearing. Gold mineralization is hosted by second- and third-order brittle to brittle–ductile strike-slip faults that developed late during the kinematic history of the Main Uralian fault. Strike-slip reactivation of earlier compressional structures was related to the late-stage docking of the passive margin of the East European platform with island-arc complexes of the southern Urals, an event that is tentatively related to changes in plate motion during the final stages of terrane accretion during the upper Permian and lower Triassic. Gold mineralization was controlled by the permeability characteristics of the hydrothermal conduits, as well as by competence contrasts and geochemistry of the mainly volcanic host rocks. Mineralization occurred at relatively shallow crustal levels (2–6 km) and largely post dates peak-metamorphism of the host rocks. The large and very large (up to 300 to Au) gold deposits of the East Uralian zone are hosted by upper-Paleozoic granitoid massifs. Gold mineralization is temporally associated with the main phase of regional-scale compressional tectonics and granite plutonism during the upper Carboniferous and lower Permian. Controlling structures have a dominantly east–west strike and occur as hybrid shear-tensional vein systems in competent granitoids subjected to east/west-directed regional shortening. Deformation textures and alteration mineral assemblages indicate lower-amphibolite-facies conditions of mineralization close to peak metamorphic conditions that are associated with the mid-Permian regional metamorphism and tectonism. Gold deposits in the southern Urals are, therefore, polygenetic and are temporally and genetically distinct in each of the two major mineralized tectonostratigraphic zones of this well-preserved collisional orogenic belt. The different timing of ore fluid generation and fluid discharge is interpreted to be the result of the different tectonic, metamorphic and magmatic evolution of terranes in the southern Urals.  相似文献   
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The lack of suitable and appropriate crops has been a poorly recognized obstacle to the application of sound agroecological practices in some temperate and tropical regions. Cultivation of traditional hybrid crops in inherently hostile environments forces increased managerial and economic expenditures. Selection of ecologically harmonious crops exploits, rather than opposes natural forces. Based in part on US-AID funded research, we have identified three crops suitable for temperate/tropical cultivation. Amaranthus is recognized in Asia and Central and South America as a food crop that can be grown as a leafy vegetable or as a seed grain in mixed croppings. It does well under a wide variety of conditions using established cultural methods. It is nutritious and highly palatable and, in many areas, is well recognized in the market place. Prosopis species (mesquite) leguminous trees occur worldwide in arid and semi-arid areas. As phreatophytes, they are resistant to drought and high temperature extremes and produce abundant yields of edible beanlike pods. Using the beans from the tree, a variety of attractive, marketable food products have been prepared. We have also identified intermediate wheat-grass, a perennial relative of wheat, as an ecologically and economically attractive alternate crop. It is already a well-established range crop; grown for seed, it becomes a useful grain intercrop. The wholegrain or endosperm mill fractions make excellent tasting, appetizing and attractive baked products. Ongoing agronomic studies indicate it is especially suitable for balancing ecologically unstable areas.  相似文献   
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