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Current Control of a continuous random variable is investigated without assuming a normal distribution. The sign test is used as test procedure. The parameters of the corresponding control chart are to be determined in such a way that in the long run the expected loss per produced item is minimal. Approximation formulas for the parameters of such an optimum control chart are derived and discussed.  相似文献   
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In discussions about the effects of part-time work on adolescents, career development processes have received little attention. This study examined relationships between part-time work and two components of career development (work values and career indecision) in 483 high school students. Comparisons of longitudinal and cross-sectional data revealed that peripheral work aspects were less valued as a consequence of being involved in part-time work; thus, the relative value placed on central work aspects increased. However, part-time work did not affect career indecision. The decision of whether to work seemed unrelated to the preexisting career development status, except for the value placed on physical activity in boys.  相似文献   
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Social Indicators Research - This paper addresses the question of whether psychological distress and subjective well-being are the opposite poles of the same axis of mental health or independent...  相似文献   
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Zedler  Joy B.  Leach  Mark K. 《Urban Ecosystems》1998,2(4):189-204
Conservation of urban wetland habitat is challenging, because multiple uses must coexist. We use examples from California and Wisconsin to describe potential synergies among recreation, restoration and research activities (the 3 R's). Allowing passive recreation is often essential to garner public support for habitat protection, restoration, and research. In turn, restoration activities can improve the appearance of degraded sites, and designing the work as a research experiment can serve the scientific community. Two projects at Tijuana Estuary support the 3 R's. (1) Oneonta Tidal Linkage is a 0.7-ha tidal channel and salt marsh that was excavated from disturbed upland to bring wetland habitat closer to the Visitor Center (thereby reducing visitor intrusion into natural marsh habitat, where endangered species would be disturbed). It supports an ambitious field experiment that is testing the importance of species diversity in restoration; it also includes a bridge that serves the interpretive program, and it adds 0.7 ha of wetland habitat that helps restore regional biodiversity. (2) A larger excavation (8 ha) of former tidal wetland will soon add wetland habitat, while testing the importance of tidal creek networks in ecosystem functioning and offering views and interpretive opportunities. A third situation, at the 485-ha University of Wisconsin–Madison Arboretum, concerns restored wet prairies, which provide habitat for native species and serve many hikers. Urban stormwater flows into and degrades the Henry Greene Prairie, allowing aggressive plants to invade. Research and restoration efforts are planned to sustain the habitat and recreation functions. These three models suggest that recreation, restoration, and research are compatible uses of urban wetland habitats.  相似文献   
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