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201.
The difficulties in resolving water resource policy questions are analogous in many ways to the difficulties in resolving energy policy questions — technical, legal, institutional and social. Federal involvement in water resources began in 1809 and continues to the present time. The most recent comprehensive study was the Second National Water Assessment by the U.S. Water Resources Council in 1979. Conclusions reached were that water quality and quantity and surface and ground water are artificial distinctions, that water policies should reflect national needs and priorities, that flood control must be accelerated and drinking water quality protected and that more decisions should be made at a local level while integrated into national planning and development. Though the study disaggregated the U.S. into 106 subregions, its projections of a single future rather than a range of futures gives an erroneous sense of predictability to the work. To help resolve the major problems, inadequate supply and contamination and flooding and erosion, ultrasophisticated mathematical models are widely utilized without sufficient verification. A more tractable approach for policy studies would be to use simplified semi-empirical models rather than first principle models. Possibly more important, policy resolution awaits social value resolution which means that the policies adopted must be flexible, incremental, and non-divisive.  相似文献   
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Establishing protected areas has long been an effective conservation strategy and is often based on readily surveyed species. The potential of any freshwater taxa to be a surrogate for other aquatic groups has not been explored fully. We compiled occurrence data on 72 species of freshwater fishes, amphibians, mussels, and aquatic reptiles for the Great Plains, Wyoming (U.S.A.). We used hierarchical Bayesian multispecies mixture models and MaxEnt models to describe species’ distributions and the program Zonation to identify areas of conservation priority for each aquatic group. The landscape‐scale factors that best characterized aquatic species’ distributions differed among groups. There was low agreement and congruence among taxa‐specific conservation priorities (<20%), meaning no surrogate priority areas would include or protect the best habitats of other aquatic taxa. Common, wideranging aquatic species were included in taxa‐specific priority areas, but rare freshwater species were not included. Thus, the development of conservation priorities based on a single freshwater aquatic group would not protect all species in the other aquatic groups.  相似文献   
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In this paper we report the results of a field study conducted for the EU project HASTE, in which the effect of IVIS task difficulty on driving performance was assessed by three concurrent methods. These included objective vehicle-related measures, subjective ratings from drivers and expert observers’ evaluations. Results showed that all three techniques were sensitive to detecting the effect of IVIS task difficulty on driving performance. As well as demonstrating a promising technique for measuring the effect of varying levels of visual spatial IVIS task on driving performance, this study highlights the value of subjective ratings and observer evaluation in assessing the effect of IVIS on driving performance.  相似文献   
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Biofuels as a renewable source of energy have gained considerable importance in recent years. The use of biofuels is expected to rise since national governments of developed nations like the US and European countries see it as one of the ways to fulfill climate targets and increase the security in their energy supply. Production of biofuels is also expected to rise as developing nations see in biofuels the opportunity for connecting to international markets through supplying a new demand in the energy market.Several studies report on the environmental, social and economic gains and detriments that can arise from increased biofuel production and consumption. However, research that provides insight into the way in which such issues are defined by actors within the product chain is scarce. In this article we analyse how the strategies and value definitions of actors involved in the production and consumption of biofuels lead to specific definitions of sustainability. The empirical material concerns the chain of palm oil production in Colombia and electricity generation in the Netherlands. It is analysed using the method of action-in-context, which allows us to uncover the level and source of diversity of sustainability definitions in the product chain.While the current growth in production of palm oil is definitely buyer driven, the analysis of various activities in the chain shows that several aspects of sustainability are defined in more complex actor fields throughout the product chain.  相似文献   
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