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991.
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The goal of universal service has dominated the telecommunications policy landscape for at least the past half century. This policy objective has been promoted with cross subsidies from long-distance telecommunications services to subscribers to local telecommunications service. The economic rationale for these cross subsidies is network externalities. In this paper, we show that: (1) the presence of network externalities, even if substantial in overall magnitude, does not generally justify a subscribership subsidy, even a well-designed one; and (2) the empirical realities of telecommunications markets make it unlikely that subscribership subsidies of any kind will increase social welfare.  相似文献   
994.
Land use optimization in watershed scale   总被引:2,自引:0,他引:2  
Managing a watershed for satisfying the inhabitant's demand is a difficult task if one has to maintain a reasonable balance between usually conflicting environmental flows and demands. The solution to these complex issues requires the use of mathematical techniques to take into account conflicting objectives. Many optimization models exist for general management systems but there is a knowledge gap in linking practical problems with the optimum use of all land resources under conflicting demands in a watershed. In the present study, an optimization problem has been formulated for the Brimvand watershed, Iran, comprising ca. 9572 ha to find out the most suitable land allocation to different land uses, viz. orchard, irrigated farming, dry farming and rangeland targeting soil erosion minimization and benefit maximization.  相似文献   
995.
Unlike other aspects of the American health experience, there is a current void of information on expensive illness experiences. This paper is designed to fill this void and prrsents an analysis of the incidence and cost of catastrophic illness in the United States. Catastrophic illness is defined as an illness episode for which a person incurs $5,000 or more of medical expenses in a calendar year. This information is used to provide a framework for focusing the debate about catastrophic and national health insurance.  相似文献   
996.
Before embarking on the development of rural areas or regions it seems necessary to answer the following key questions: what goals of the parties involved can be realized, and where, when and how? To tackle these questions we have developed a ‘roadmap’, as part of an overall sustainable development procedure for physical planning and spatial management in rural areas. The roadmap is a tool for the process manager and the people involved. It helps to find the way in the exploration of the potential social, economic and ecological benefits of developing the area or region. The purpose of using the roadmap is to alleviate doubts about the advantages of cooperating in pursuit of sustainable development. A back-casting approach is applied to create appealing visions of the future and visualize mutual opportunities worth implementing. In this article we first describe the need for this new roadmap. We then describe its use, step by step and in some detail. An example of the exploration process is described and the strengths and weaknesses of the roadmap are discussed.  相似文献   
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In rich economies emissions of many pollutants tend to grow at a slower rate than GDP. This could be a result of shifting comparative advantages. If so, net imports of dirty products to these economies will increase and rather than reduced, emissions will be relocated to other countries. In this paper we investigate if decoupling in a rich, open economy coincides with such pollution leakages abroad. Based on historical observations and model projections, we find little evidence to support this hypothesis. Historically, decoupling coincides with falling pollution leakages. Projections over a period of decades indicate a weakening of the decoupling, but that leakages will increase.  相似文献   
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