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131.
针对目前我国道路交通事故多发的现状,以模糊Petri网为工具,以对道路交通安全有重大影响的关键因素为基础,模拟给出其因果关系,建立了基于模糊Petri网的道路交通事故致因分析模型,设计最长路径算法分析模型中某个致因要素导致交通事故发生的可信度。最长路径上的致因要素即为最易引起交通事故的主要因素。案例分析表明,这个模型能够体现各因素之间的逻辑关系,达到了通过数量指标分析道路交通事故主要原因的目的。  相似文献   
132.
The ranking of air quality control measures according to a number of evaluation criteria and with the participation of a large number of interested publics is demonstrated. A pilot study for the South Coast Air Quality Management District of California serves as the reference point. Several methodological considerations are addressed, such as: (a) the enhancement of criterion priorities to account for the variability among the performance of the control measures when incommensurable impact levels are applied: (b) the derivation of alternative rankings according to the priorities of potential coalitions; (c) the assessment of the potential acceptability of a collective ranking given the degree of solidarity among participants with similar interest affiliations; and (b) the assessment of the extent to which the performance of specific control measures may override priority differences and lead to insignificant ranking differences.  相似文献   
133.
Abstract: The commercial trade of wildlife occurs on a global scale. In addition to removing animals from their native populations, this trade may lead to the release and subsequent introduction of nonindigenous species and the pathogens they carry. Emerging infectious diseases, such as chytridiomycosis caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), and ranaviral disease have spread with global trade in amphibians and are linked to amphibian declines and die‐offs worldwide, which suggests that the commercial trade in amphibians may be a source of pathogen pollution. We screened tiger salamanders involved in the bait trade in the western United States for both ranaviruses and Bd with polymerase chain reaction and used oral reports from bait shops and ranavirus DNA sequences from infected bait salamanders to determine how these animals and their pathogens are moved geographically by commerce. In addition, we conducted 2 surveys of anglers to determine how often tiger salamanders are used as bait and how often they are released into fishing waters by anglers, and organized bait‐shop surveys to determine whether tiger salamanders are released back into the wild after being housed in bait shops. Ranaviruses were detected in the tiger salamander bait trade in Arizona, Colorado, and New Mexico, and Bd was detected in Arizona bait shops. Ranaviruses were spread geographically through the bait trade. All tiger salamanders in the bait trade were collected from the wild, and in general they moved east to west and north to south, bringing with them their multiple ranavirus strains. Finally, 26–73% of anglers used tiger salamanders as fishing bait, 26–67% of anglers released tiger salamanders bought as bait into fishing waters, and 4% of bait shops released tiger salamanders back into the wild after they were housed in shops with infected animals. The tiger salamander bait trade in the western United States is a useful model for understanding the consequences of the unregulated anthropogenic movement of amphibians and their pathogens through trade.  相似文献   
134.
Fisheries management is increasingly transitioning towards collaborative governance. Collaborative systems depend on stakeholders’ capacity to design and implement legitimate and scientifically robust management plans within collective action arenas. Here we propose that collaborative governance outcomes, in fisheries management, will benefit from using structured participatory decision making frameworks that enhance deliberative thinking among stakeholders. We tested our approach in the artisanal fishery of Chile, an important producer of marine resources. Recently in 2013, Chile made important changes to fisheries policies by creating multi-sectorial management committees to manage de facto open access fishing areas. We applied a structured decision making framework to inform the restructuring of a management plan within a committee. As a result, we identified goals,objectives and indicators, including social, economic, biological and ecological dimensions; we explored tradeoffs, assessing the relative importance of the objectives; finally, we created scenarios and prioritized alternatives, reflecting on the interplay between self-regulation and government control. Members of the management committee were able to rationalize the different steps of the framework and identify ways forward which highlighted the importance of self-regulation in comparison to central authorities’ control. We concluded that structured decision making promotes spaces for rational analysis of alternatives costs and benefits. Promoting deliberative thinking in fisheries management can improve equity, legitimacy and sustainability of collaborative governance.  相似文献   
135.
渔业环境权是渔业权人在得到许可的渔业水域从事养殖、捕捞等生产活动时所拥有的保护渔业水域环境的权利。根据物权理论,渔业环境权是一种基于国家对渔业水域的所有权上派生的用益物权,是《物权法》中养殖权和捕捞权的构成要件,它同养殖或捕捞水生动(植)物的所有权、对得到许可的水域(水体)的占有或使用权一起,构成完整的养殖权或捕捞权。这就是现行法律制度没有规定独立的渔业环境权的原因。  相似文献   
136.
安徽省农民人均纯收入地域差异及其原因分析   总被引:1,自引:0,他引:1  
以SPSS V13.0、Excel、Eviews 3.1和ArcView GIS3.2为工具,运用层次聚类分析和相关分析等方法,分析了安徽省农民人均纯收入的地域差异以及引起地域差异的原因。结果表明,安徽省农民人均纯收入的地域分异由东南向西北递减,并与经济发展水平区内分异性相吻合,这种差异是由自然条件差异和社会条件差异共同造成的。本研究对安徽省农村区域发展均衡性具有一定的指导意义。  相似文献   
137.
区域生态承载力与可持续发展   总被引:35,自引:1,他引:34  
本文探讨了生态承载力的概念和估测的方法,分析了大陆典型生态系统净第一性生产力的背景值,研究了确定自然系统最优生态承载力的依据,在此基础上,提出了提高区域生态承载力,实现区域可持续发展基本对策。  相似文献   
138.
This study analyzes the fishing areas or spots used by artisanal fishers of the Atlantic Forest coast. Fishers include inhabitants of islands of the SE Atlantic Forest in Brazil. Data on fish landings were collected for different islands, in 1986 and 1989–1990, for species caught, technology used and fishing time. Fishing spots were marked or rechecked using GPS in 1997–1999. Fishing is performed in paddled, motorized canoes or in small boats with set gillnets or hook and line. Marine animals caught vary from place to place and include fish, shrimp, squid and crab. Spots used are very stable in time, since they did not change for about 10 years. Among other factors, technology limits the range of access of the fishers to the spots. An informal division of fishing areas or spots is observed, based on the locality of residence of the fishers. The mapping and observed division of fishing spots may be used in local management, helping to control the intrusion of industrial fishers in artisanal areas. Local rules and discrimination of spot users may be helpful for artisanal fishers, especially in areas where conflicts with trawlers occur. The observed long-term stability of the use of fishing spots by artisanal fishers and conflicts with other users indicate the urgency of considering local rules for conservation purposes in Atlantic Forest coastal areas. Electronic Publication  相似文献   
139.
研究西南地区陆地植被生态系统净初级生产力(NPP)的时空演变特征及其驱动力,对区域生态环境保护具有重要的现实意义.利用2000~2021年MODIS NPP、1999~2021年基于站点的气象数据和2000~2020年土地利用类型等数据,结合主成分分析、残差分析、Theil-Sen Median趋势分析和偏相关分析等方法,研究西南地区陆地植被生态系统NPP时空演变及其对驱动力的响应特征.结果表明,时间上,2000~2021年西南地区植被NPP呈波动上升趋势,速率为3.54g·(m2·a)-1.气候变化和人类活动影响下,农田、草地和森林生态系统NPP均呈上升趋势,但农田生态系统NPP的上升趋势最为显著.空间上,西南地区植被NPP呈上升趋势的面积占比为89.06%,显著上升和极显著上升的区域主要分布在广西南部、四川东部、重庆西部,以及云南和贵州交界处.气候变化和人类活动对西南地区植被生长具有双重影响,气候变化和人类活动影响下农田生态系统NPP呈上升趋势的面积占比均高于草地和森林生态系统.西南地区植被NPP与各气象因子的相关性呈明显地域差异.区域尺...  相似文献   
140.
草原区作为影响我国陆地生态系统碳水循环和生态安全的重点区域,对气候变化和人类活动极为敏感.然而,有关气候变化和人类活动对该区域植被恢复相对贡献的认识尚存分歧.以生态系统净初级生产力(NPP)为评价指标,通过对比MODIS观测的实际NPP和基于Thornthwaite Memorial模型估算的潜在NPP的趋势差异,量化了2000~2020年气候变化和人类活动对我国典型草原区(北方温性草原区和青藏高原高寒草原区)植被恢复的相对作用.结果表明,研究区内93%的草地植被呈恢复趋势,NPP平均增加速率达(以C计)2.12 g·(m2·a)-1(P<0.01),其中,近一半植被恢复区受气候变化和人为活动共同控制,约36%和10%植被恢复区分别受气候变化和人类活动的独立控制;此外,不同草地类型气候变化主导植被恢复的面积占比差异大,主要表现为高寒草地明显高于温性草地,气候条件越干旱,气候主导面积占比越大.人类活动不是北方温性草原区和青藏高原高寒草原区植被恢复的主要原因,但在气候条件恶化地区,人类活动可降低甚至抵消气候变化对植被的负面影响.未来需加强长...  相似文献   
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