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本文论述了城市供水及污水处理中存在的问题,提出了解决城市供水和污水处理问题的基本原则,进而提出建立供水与污水处理一体化企业经营模式,以解决城市污水处理问题。 相似文献
204.
ABSTRACT: Increasing specialization separates animal production from cropland, complicating manure management. To assist policy targeting efforts, we highlight areas where on-farm use of manure may be problematic. Matching confined animal production with land, on the farm- rather than at the county-level, gives our analysis an advantage over previous studies in avoiding aggregation problems. With manure-based water quality problems, data aggregated to the county level may fail to convey the heterogeneity of animal production across regions and animal types. Aggregation bias blurs the distinction between areas with specialized animal production and those that merely have numerous animals. We estimate bias from using county aggregates, show its distribution spatially and by animal sector, and link it to concentration. Ongoing vertical integration in agriculture likely alters in-county variability in facility scale and scope, and may influence decisions about which data we should gather and use. 相似文献
205.
南京市将发展为特大城市,城市空间的拓展已将江宁区、江浦县划为南京市的次区域中心。在分析两地发展功能转变及其与主城生态整合关系的基础上,提出产业生态化的主要建设领域及环境建设、生态保护对策。 相似文献
206.
Christine A. Johnson Howard Topoff Robert K. Vander Meer Barry Lavine 《Behavioral ecology and sociobiology》2005,57(3):245-255
Social parasites exploit the behaviours of other social species. Infiltration of host systems involves a variety of mechanisms depending on the conditions within the host society and the needs of the social parasite. For many species of socially parasitic ants, colony establishment entails the usurpation of colonies of other species. This frequently involves the eviction or death of the host colony queen and the subsequent adoption of the invading queen. The social parasite queen achieves host worker acceptance by either manipulating the nest-mate recognition processes of the host or undergoing chemical modification. Little is known, however, about how host workers respond to social parasite eggs or whether host species defend against brood parasitism during parasite invasions. Host species are believed to adopt social parasite offspring because the recent common ancestry between many social parasites and their hosts may grant the sharing of certain characteristics such as chemical cues. Use of multiple host species, however, suggests other processes are needed for the social bond between host and parasite young to form. This study reports the findings of adoption bioassays in which eggs from a slave-maker ant, Polyergus breviceps, were offered to workers of two of its host species from unparasitised or newly parasitised nests to determine whether P. breviceps eggs generally elicit rearing behaviours from multiple host species. Comparisons of parasite egg survival until adulthood with conspecific egg survival reveal that workers of both host species, free-living or newly enslaved, do not typically accept slave-maker eggs. Both host species thus have sufficient discriminatory power to reject social parasite eggs although our hydrocarbon analysis indicates parasite eggs may be adapted to their local host species. Combined these results suggest that host rearing of P. breviceps eggs may reflect an evolutionary equilibrium that is maintained by probability and cost of recognition errors.Communicated by L. Sundström 相似文献
207.
208.
《Environmental Hazards》2013,12(3):301-318
This review paper takes a case study approach to critically discuss how regeneration in the coastal resort of Porthcawl, South Wales has integrated flood defences as part of a strategic spatial planning and integrated policy coupling approach to the redesign of the town's seaside, promenade and harbour quarter. This planned initiative is part of a concerted effort to upgrade the town's waterfront and enable regeneration of a small seaside resort. From a resort cycle perspective, Porthcawl's perceived vulnerability to changing economic fortunes has prompted a master planning approach which is intended to bring together a mixed-use development programme with particular attention to urban design, strategic environmental assessment and public consultation. In different ways, this process has sought to raise public awareness of the issues and risks associated with the town's coastal location and to integrate flood defence aspects within the strategic regeneration plan as part of a greater sensitivity to climatic risks and potential flooding. This paper examines the adaptive capacity of coastal communities and the complex of socio-economic and spatio-temporal perspectives that shape policy developments in the planning, development and proactive management of coastal environments. The paper identifies the need to accommodate a new civic awareness of potential environmental hazards in articulating the public interest and balancing the trade-offs involved. 相似文献
209.
论水资源格局与可持续发展 总被引:8,自引:0,他引:8
孟庆民 《中国人口.资源与环境》1999,9(2):26-30
以可持续发展理论为指导,分析了我国水资源自然格局及利用格局的现状与问题,提出了作为可持续发展重要支撑的水资源,其可持续利用的根本途径是建立可持续发展的水资源格局,即流域经济系统格局,并实现流域基础上的区域竞争与协作一体化 相似文献
210.
洪灾遥感监测与信息复合分析 总被引:2,自引:0,他引:2
本文分析了单一遥感信息在洪灾监测中的局限性;探讨了同一区域内遥感信息之间或遥感信息与非遥感信息之间的匹配复合,并就信息复合技术在洪灾监测中的应用作了论述。 相似文献