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91.
We examine the role of food resources on split sex ratios in Formica exsecta. Models of resource-based sex allocation predict that greater resources will cause an increase in the production of reproductive females (gynes) and an increase in overall size of offspring. We experimentally increased food resources for a subset of colonies in a polygynous population with a very male-biased sex ratio. This increase in food availability caused colonies that were male specialists the prior year to switch to female production. Overall, a significantly greater proportion of food-supplemented colonies produced gynes, compared to control colonies. Moreover, food-supplemented colonies produced significantly larger workers and males (but not gynes), compared to those produced by control colonies. There was, however, no significant difference in the numerical productivity of food-supplemented and control colonies. We also measured the natural association between colony sex specialization and proximity to conifers, which typically harbor honeydew-bearing aphids (an important natural food source). In line with the view that resources play an important role for determining sex ratios in social insects, we found that female-producing colonies were significantly closer to conifers than were male-producing colonies. 相似文献
92.
Effective planning of resources management is important for facilitating socio-economic development and eco-environmental sustainability. Such a planning effort is complicated with a variety of uncertain, dynamic and nonlinear factors as well as their interactions. In this study, an inexact-stochastic quadratic programming with recourse (ISQP-R) method is developed for reflecting dynamics of system uncertainties based on a complete set of scenarios as well as tackling nonlinearities in the objective function to reflect the effects of marginal utility on system benefits and costs. Moreover, since penalties are exercised with recourse against any infeasibility, the ISQP-R can support the analysis of various policy scenarios that are associated with different levels of economic consequences when the promised targets are violated. The developed method is applied to a case study of planning resources management and developing regional ecological sustainability. The results have been generated and are helpful for decision makers in not only identifying desired resources-allocation strategies but also gaining insight into the tradeoff between economic objective and eco-environment violation risk. 相似文献
93.
DeVerle P. Harris 《Resources Policy》1984,10(2):81-100
Political-economic events of the 1970s brought mineral resource appraisal to the focus of national policy. Estimates of and methodologies for mineral resources appraisal were scrutinized, revealing deficiencies in method and data and fostering considerable debate about the credibility of estimates and about preferred methodology. Since credibility can be increased through the acquisition of additional geoscience information, questions regarding methodology have more than one formulation and therefore more than one correct solution, depending upon the expected value of additional information and the conditional losses of relevant policy options. When existing information is meagre and the expected value of information is high, the optimum decision may be to defer all policy options until after the acquisition and analysis of- additional information. Decision theory offers an analytical framework that is sufficiently generalized to provide answers for highly varied circumstances of geoscience and resource information and policy issues. Our ability to perform any such analysis is limited by inaccuracies in both geologists' estimates of undiscovered mineral resources, and in economists' calculations of conditional losses of policy options for each of the relevant states of mineral resources. 相似文献
94.
Siar SV 《Environmental management》2003,31(5):0569-0580
The coastal zone is a place of intense activity where resources, users, and resource-use practices interact. This case study
of small-scale fisheries in Honda Bay, Palawan, Philippines shows that resources, space, and gender are intertwined. The study
was conducted between June 1997 and July 1998. The data were gathered using free listing, pile sort, ranking, resource mapping,
and key informant interviews. The results showed that women's knowledge about fishery resources and their fishing activities
are associated with the intertidal zone whereas men's knowledge is associated with coral reefs. In classifying fishery resources,
appearance is the main consideration for women whereas a combination of appearance, habitat, and type of fishing gear is the
consideration used by men. Market price is very important because of its dependence on the demand of the export market as
well as the local market. Women dominate the buying of fishery products. Many women market their husband's catch, process
fish, or gather shells and sea cucumber for sale. Among the fishing households, type of fishing gear provides an indication
of socioeconomic standing. This paper concludes that access to resources is shaped by gender and age. The differences in resource
knowledge possessed by men and women lead to differential access to fishery resources. In addition, the differences in socioeconomic
status also influence resource access. The socialization of children into fishing reinforces the gender division of labor
and space in the coastal zone. 相似文献
95.
96.
经济的快速发展促进了城市化进程,同时也带来了资源与环境问题。在此,针对城镇化进程中的环境变化特点,以昆山市为例,分析制定了符合生态经济规律的小城镇规划。以加强土地管理和环境管理,加快乡村城镇化进程,实施乡镇工业经济增长方式的转变。 相似文献
97.
根据上海市新一轮环保三年行动计划(2006~2008年)要求,上海将在未来3年中完成全市11家电厂的35台约6508MW燃煤发电机组的烟气脱硫工程,这同时将产生大量的烟气脱硫副产品——脱硫石膏,处置和利用好脱硫石膏,对上海市的生态环境保护有着重要的意义。阐述了燃煤电厂烟气脱硫石膏的特性和国内外脱硫石膏的利用现状。结合上海实际,对烟气脱硫石膏在建筑建材业.农业等领域的应用前景进行了分析。指出烟气脱硫石膏的资源化利用符合循环经济理念,并能产生良好的环境、社会和经济效益。提出了烟气脱硫石膏的利用建议。 相似文献
98.
99.
江苏省循环经济建设的实践与探索 总被引:2,自引:0,他引:2
根据江苏经济发展的奋斗目标,从分析江苏经济环境的实际出发,阐述了江苏发展循环经济建设的必要性,总结了全省开展循环经济建设工作经验,分析了循环经济建设工作存在的问题。 相似文献
100.