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181.
182.
Genetic engineering evokes a number of objections that are not directed at the negative effects the technique might have on the health and welfare of the modified animals. The concept of animal integrity is often invoked to articulate these kind of objections. Moreover, in reaction to the advent of genetic engineering, the concept has been extended from the level of the individual animal to the level of the genome and of the species. However, the concept of animal integrity was not developed in the context of genetic engineering. Given this external origin, the aim of this paper is to critically examine the assumption that the concept of integrity, including its extensions to the level of the genome and the species, is suitable to articulate and justify moral objections more specifically directed at the genetic engineering of animals.  相似文献   
183.
We develop an optimal control model for cost-effective management of pollution, including two state variables, pollution stock and ecosystem quality. We apply it to Baltic Sea pollution by nitrogen leachates from agriculture. We present a sophisticated, non-linear model of leaching abatement costs, and a simple model of nitrogen stocks. We find that significant abatement is achievable at reasonable cost, despite the countervailing effects of existing agricultural policies such as price supports. Successful abatement should lead to lower nitrogen stocks in the sea in 5 years or less. However, the rate of ecosystem recovery is less certain. The results are highly dependent on the rate of self-cleaning of the Baltic Sea, and less so on the discount rate. Choice of target has a radical effect on the abatement path chosen. Cost-effectiveness demands such a choice, and should therefore be used with care when stock effects are present.  相似文献   
184.
185.
In this study, a tracer bacteria was used to investigate the resuspension and persistence of sediment-associated bacteria in a small alluvial stream. The study was conducted in Swan Creek, located within the Grand River watershed of Ontario, Canada. A 1.1-m2 section of the bed was seeded with a strain of Escherichia coli resistant to nalidixic acid (E. coli NAR). The survival, transport, and redistribution of the tracer bacteria within a 1.7-km river section downstream of the source cell was assessed for a 2-mo period following the introduction of the tracer bacteria. This study has illustrated that enteric bacteria can survive in bed sediments for up 6 wk and that inactivation of the tracer bacteria resembled typical first-order decay. Critical conditions for resuspension, as well as resuspension rates, of sediment-associated bacteria were determined for several storm events. The critical shear stress for E. coli NAR resuspension in Swan Creek ranged from 1.5 to 1.7 N m(-2), which is comparable with literature values for critical shear stresses for erosion of cohesive sediments. Bacteria resuspension was primarily limited to the rising limb of storm hydrographs implying that a finite supply of sediment-associated bacteria are available for resuspension during individual storm events. The information presented in this paper will further the development of representative microbial water quality models.  相似文献   
186.
The self-sealing/self-healing (SS/SH) barrier concept is based on the principle that two or more parent materials placed in vertical or horizontal layers will react at their interfaces to form insoluble reaction products. These products constitute a seamless impermeable seal, which is resistant to the transmission of leachate and contaminants. A SS/SH liner formulation was developed in the laboratory and demonstrated at the Sudokwon landfill site in South Korea. Laboratory testing results indicated that a seal with a hydraulic conductivity less than 10(-9) m/s formed after two to four weeks of curing at room temperature, and the seal healed itself after it was fractured. The use of the soil from the Sudokwon landfill site instead of sand as the matrix of the parent materials in the SS/SH liner retarded the sealing and healing of the seal, but did not show an obvious effect on the overall sealing and healing capacity of the seal at early stages. The construction and installation of the field demonstration SS/SH liner were carried out in the same way as for a soil cement liner. The quality of the liner was ensured by the enforcement of quality analysis/quality control procedures during installation. A single sealed ring infiltration test was performed on the field demonstration liner 36 days after the installation was completed. The measurement of water infiltration rate indicated that the liner healed after it was fractured. However, the long-term sealing and healing capacity needs to be further investigated.  相似文献   
187.
The approach proposed in this study provides insight into the influence of the basement geochemistry on the spatial distribution of radon (222Rn) levels both at the soil/atmosphere interface and in the atmosphere. We combine different types of in situ radon measurements and a geochemical classification of the lithologies, based on 1/50,000 geological maps, and on their trace element (U, Th) contents. The advantages of this approach are validated by a survey of a stable basement area of Hercynian age, located in South Brittany (western France) and characterized by metamorphic rocks and granitoids displaying a wide range of uranium contents. The radon source-term of the lithologies, their uranium content, is most likely to be the primary parameter which controls the radon concentrations in the outdoor environment. Indeed, the highest radon levels (> or = 100 Bq m-3 in the atmosphere, > or = 100 mBq m-2 s-1 at the surface of the soil) are mostly observed on lithologies whose mean uranium content can exceed 8 ppm and which correspond to peraluminous leucogranites or metagranitoids derived from uraniferous granitoids.  相似文献   
188.
This paper investigates the suitability and limitations of the Strategic Niche Management framework in the context of emerging economies of South and East Asia. We explore several learning-based approaches to development projects that are part of the academic and practitioner field of development studies. The approaches show similarities with SNM but they reflect the developing-country context within which they were framed, and are also more geared towards local community development and capacity building. We apply these approaches to four biomass energy projects in rural India to identify determinants of success and failure. We then discuss how these findings compare with the insights that an SNM analysis would have offered. We arrive at the following conclusions. First, the great strengths of SNM are its explicit conceptualisation of environmental sustainability and its endogenous treatment of the larger context. Second, the learning-based development approaches hone in on the complexities of local management and stakeholder organisation. Third, they also bring out the great importance of local institutions such as traditional status and power differences. Fourth, we conclude that SNM holds considerable promise for application in a developing Asian context, but that its usefulness and relevance in that setting could be enhanced by incorporating these additional issues.  相似文献   
189.
This paper explores the lessons learned by leaders in agricultural adaptation planning in order to assist other jurisdictions to develop adaptation strategies. It seeks to identify effective institutional, participatory and collaborative processes involved in designing agricultural adaptation strategies at the national and sub-national levels in Germany, Finland, the United Kingdom, the United States and Canada. Its methodology is based on review of agricultural adaptation policy documents, research initiatives, stakeholder engagement processes, and cross-sectoral collaborations as well as interviews with key informants such as leaders and actors in adaptation planning. The gathered data show that early adapters have an improved regional and national understanding of climatic impacts, and of the risks to agriculture before the initiation of the planning process. The results indicate that the interplay between bottom-up and top-down initiatives has been crucial in the development of adaptation strategies. The former has provided rich and robust participation in designing, implementing and monitoring adaptations, while the latter was important for prioritizing and legitimizing the development of strategy. It also provided access to high-level decision makers and funding. The results of the study suggest that fostering cross-sectoral collaborations—especially by focusing on broader questions such as the role of agriculture in society—has become an important part of adaptation planning. Finally, our results also stress that adaptation planning in agriculture could be enhanced by skills development and mutual learning across stakeholder groups, research and policy-makers, and through the ongoing interactive development of institutional capabilities.  相似文献   
190.
Abstract

The overall purpose of this study was to assess whether interaction with a regionally based computer simulation software tool, Gb-Quest, was an effective tool for learning about sustainability. A questionnaire was administered to 189 participants, before and after attending a workshop on Gb-Quest. Factor analysis was used to determine the factor structure of the three scales used in this study. Seven variables were identified and were examined for group differences (gender, age, and whether or not they were Canadian born). In particular, younger individuals and males were more likely to endorse the view that the earth is being destroyed by humans. In addition, Canadian-born individuals were more likely to endorse the consumption of environmentally friendly products, but less likely to be supportive of development and using public transportation. We also examined change for each of the variables and found that Gb-Quest had an effect on all of them. Findings are discussed in terms of implications for future research.  相似文献   
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