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831.
832.
Walter W. Zwirner 《Environmental monitoring and assessment》1991,17(2-3):247-252
Sampling inference is proposed as an alternate paradigm. This method is discussed with respect to classical, Bayesian and a proposed probabilistic real world system. A probabilistic real world system is suggested as more valid and useful in practical as well as research situations. Sampling inference applied to a probabilistic model allows for valid inferences for volunteer and representative as well as random samples. A concept of time and distance based samples is introduced. 相似文献
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836.
In considering the prospects for sustainable energy, most studies have focused on developments in the urban and industrial areas. However, in Asia where the bulk of the population continues to live in rural areas, it is essential to monitor the changes occurring in the countryside. Therefore, this paper examines the developments taking place in rural energy in Asia in general and focuses specifically on the situation in China. It is observed that a total reorganization of the energy picture is occurring in rural China with regard to both conventional and non-conventional energy, as a result of the huge market for power and fuel created by rapid economic growth. This has led to new distribution networks for electricity (with the Chinese Government following the example of the US Rural Electrification Administration), fossil fuels and renewable energy systems. The growing affluence of the population coupled with rapid industrialization is producing far-reaching changes in the transportation structure as well as in the household energy structure. The situation in China is seen to be comparable to that in other East and Southeast Asian countries, particularly those which combine a rapidly growing industrial sector with a large rural population engaged in agriculture, such as the Republic of Korea, Thailand, and Indonesia. 相似文献
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838.
Walter D. S. Leal Filho 《The Environmentalist》1990,10(3):219-221
Summary In this short article the author analyses some of the causes for the recent depletion in the natural fauna and wildlife of Brazil. A plea for support in their protection is made.Dr Walter Leal Filho is a Brazilian biologist who has recently completed a PhD programme in Environmental Sciences at Bradford University, UK. He has been collaborating in a wide range of conservationist projects in Brazil and has published a number of articles and papers promoting the conservation of Brazilian fauna and flora, including the bookEcology and Education. 相似文献
839.
Fire ant polymorphism: the ergonomics of brood production 总被引:3,自引:0,他引:3
Summary Social organization is generally assumed to increase colony efficiency and survival; however, little quantitative information is available to support this assumption. Polymorphism is an important aspect of labor division in colonies of the fire ant, Solenopsis invicta. Our objective was to investigate the effect of fire ant polymorphism on brood production efficiency. We set up standardized polymorphic colonies with a full range of worker sizes and artificial monomorphic colonies that contained only small, medium or large workers respectively. Polymorphic colonies produced brood at about the same rate as colonies composed of only small workers (Fig. 2A). Colonies composed of only medium workers produced about 30% less brood, and colonies composed of only large workers produced little or no brood at all. This pattern was independent of colony size; however, smaller colonies (0.75 g, live weight) produced almost twice as much brood per gram of workers as larger colonies (3.0g). Additional experiments revealed that the size of workers in the artificial monomorphic colonies affected all stages of brood rearing. Large workers not only inhibited the development of early and late instar larvae (Fig 4), but also reduced the queen's oviposition rate (Fig. 3). Brood production efficiency on an energetic basis was determined by dividing the grams of brood produced per unit time by the energetic costs expended for the maintenance and production of each worker size class. Worker maintenance costs were estimated from respiration while production costs were determined from the caloric content of worker tissue divided by their average longevity. Worker respiration per milligram body weight decreased about 40% as body size increased (Fig. 5). Large workers lived about 50% longer than small workers (Fig. 6) and contained 9% more energy per milligram of tissue (Fig. 7). Energetic efficiency in polymorphic colonies was approximately 10% higher than in colonies composed of only small workers (Fig. 9). In other words, when food supplies are limiting, polymorphism may offer a slight advantage in brood production. 相似文献
840.
Increased attention has recently been given to the possible role of financial services in the management of natural disaster risk. Local communities have been at the forefront of developing innovative disaster risk finance strategies and implementing risk-oriented incentive programs. In view of increasing risks, including the impacts of climate change, such programs will become more important. This paper examines four models and some recent experiences in using financial services at the community level. The paper offers an overview of advantages and limitations of each model to manage disaster risk in communities. Examples include a federal government initiated scheme of social protection funds, a local government risk reduction scheme, an insurance product provided by a non-governmental organization , and a micro-insurance scheme. Finally, the paper offers some directions about specific ways that the public and private sectors, in collaboration with other partners can improve finance alternatives for disaster management at the community level. It appears that a range of follow-up studies and further dialogue is needed, in order to expand the knowledge on what types of risk finance models can help manage and reduce the financial impacts of natural disasters. 相似文献