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111.
通过遥感手段,利用大量的ETM、TM、MSS遥感影像,从土地覆盖变化、景观格局指数等角度,分析了近30年七里海湿地的土地利用变化特点及景观演替趋势特征。详细分析了七里海内水域、芦苇等用地类型的转化趋势与成因,并通过多年来景观指数对比的方法揭示了该区域景观连通性和破碎化程度的变化趋势。研究结果表明:由于入境水量减少,1976到2009年期间七里海湿地水域面积减少了80%,之后由于保护区的建立,水域面积持续增长。期间以保护区建立为节点,主要的土地利用类型变化趋势是水域-芦苇-水域。1976到2009年期问七里海总体聚集度指数从95.75下降到87.54、水面的破碎化指数从6.42上升到10.74,反映出区域景观连通性变差,破碎化程度在加剧,人类活动对环境影响越来越深刻。 相似文献
112.
陈立峰 《中国安全生产科学技术》2012,8(8):176-179
随着宁夏经济社会发展,消防部队作为政府领导下的一支综合性应急救援队伍,面对安全需求激增、救援任务多元化、复杂化等新形势,还存在着人员不足、素质不高、装备落后、教育训练模式滞后和缺乏高效社会联动救援机制等问题,消防应急救援整体水平亟待提高。通过深入分析消防应急救援工作形势及现状,从改革执勤战备、加强救援力量建设、创新训练方式、优化装备结构、加强信息化建设和救援机制建设等方面,提出了一系列提高消防应急救援工作水平的思路和措施。 相似文献
113.
长江中游湿地系统驱动关系的演变及保护展望 总被引:5,自引:0,他引:5
简要介绍了长江中游湿地的概况,分析了湿地演变的现状。在自然和人为因素长期、综合作用下,长江中游湿地发生了显著的不合理演变,主要表现在:湖泊面积减少,湿地功能下降;湿地资源的过度和不合理利用,生物多样性下降;湿地环境污染日益严重;湿地整体价值受损。重点对湿地系统演变过程中的几个关键驱动关系进行了探讨,包括江湖关系、蓄泄关系、湖垸关系和山湖(河)关系等。在此基础上,针对长江中游湿地演变的现状和利用保护过程中存在的问题,从流域综合管理角度出发,对长江中游湿地的保护进行了展望,提出了基于流域管理思想的长江中游湿地保护对策和措施,主要包括:加强流域统一协调管理;遵循流域管理原则,理顺湿地系统的各种关系,做好湿地生态规划;加强流域生态管理模式研究;加强长江中上游流域水土流失的综合治理;加强自然保护区建设和管理,保护湿地生物多样性。 相似文献
114.
为系统地认识女性驾驶人的驾驶特性,分析其驾驶行为,从女性驾驶人交通事故数据统计、致因和心理、生理、“药驾”等因素,梳理国内外女性驾驶人驾驶特性及行为机制的研究成果,总结主流研究角度、方法和内容,并展望其未来研究趋势。对文献的梳理和分析表明:导致女性驾驶人交通事故的因素主要包括人格、认知等心理特征和视觉能力、应激反应等生理特征,同时“药驾”也影响着驾驶特性与行为。剖析了女性驾驶人特性及行为机制研究目前存在的不足之处,对未来的研究提出了建议。并针对女性驾驶人群体在各种道路交通环境中开展有效的模拟驾驶培训和教育,进而全面提升中国女性驾驶人的交通安全水平。 相似文献
115.
Dongmei JIANG Xiaoshun LI Futian QU Mingyan LI Shaoliang ZHANG Yunlong GONG Xiaoping SHI Xin CHEN 《Frontiers of Environmental Science & Engineering》2015,9(2):298
Since the reform and opening-up, China’s economy has achieved remarkable development and so does the urbanization. However, there is an unavoidable contradiction between urban sprawl and the protection of arable land and the environment. By redefining the urban sprawl boundary, this paper is to provide a solution for the conflict above on the China’s urbanization context. The ideal boundary, moderate boundary and limit boundary are defined for urban sprawl in space. Taking Nanjing city as a case, the three urban sprawl boundaries are estimated in this paper based on the calculation of agricultural land resources value in Nanjing. The results show that 1) the integrated value of agricultural (cultivated) land resources in Nanjing is 1.55 × 107 CNY·hm−2, the economic value accounts for only 8.74% of the integrated value, while 91.26% of the integrated value has not revealed itself due to the existing institutional arrangements, policy distortions, and imperfect land market; 2) it is difficult to define the ideal and moderate boundaries due to the relatively low price of North Nanjing. In South Nanjing the land price is expensive and the ideal, moderate and limit boundaries are expanded to Jiangning, Qixia, and Yuhuatai; 3) the city scale of South Nanjing should be limited within 5.82 × 104 hm2, which is roughly the same as the designated size of 5.81 × 104 hm2 in the urban planning. It is suggested that the rational scope of urban expansion should be controlled within the moderate boundary. 相似文献
116.
The likely extension of commercial inland navigation in the future could increase hazards directly impacting on the nurseries of freshwater fish, especially for smaller individuals with limited swimming abilities. One limitation of the evaluation of inland navigation on fish assemblages is the lack of suitable hydraulic models. This article presents a hydraulic model to assess the increase of navigation-induced physical forces due to higher vessel speed, length, and drought in a low-flowing waterway related to maximum swimming performance of fish to (1) foresee hazards of enhancement of inland navigation, (2) derive construction measures to minimize the hydraulic impact on small fish, and (3) improve fish recruitment in waterways.The derived model computed current velocities induced by passing commercial vessels in inland waterways experimentally verified and parameterized in a German lowland waterway. Results were linked with a model of maximum fish swimming performance to elucidate consequences for freshwater fish populations. The absolute magnitude of navigation-induced current limits the availability of littoral habitats for small fish. Typical navigation-induced current velocities of 0.7–1 m/s in the straight reaches of waterways will be maintained by fish longer than 42 mm only. Smaller juveniles unable to withstand those currents could become washed out, injured, or displaced. In contrast, in small local bays, the navigation-induced current declined significantly. According to our model, in a 20-m extended bay, the return current drops below 0.11 m/s, corresponding to the maximum swimming speed of a 9-mm-long fish. Thus, enhancing shoreline development by connecting oxbows, tributaries, and especially by purpose-built bays limits the impact on fish recruitment without restricting navigation resulting in more precautionary and sustainable inland navigation. 相似文献
117.
PROBLEM: This paper explores the potential use of on-road driving evaluations as a tool for helping older adults extend their safe driving years. METHOD: Three separate research activities were carried out. The first was a national telephone survey of current and former older drivers. The results of this survey provide information relevant to the potential market for on-road driving evaluations. The second was a series of focus groups with potential stakeholders in the process: driver educators, occupational therapists, and physicians. These groups explored the feasibility and requirements of offering on-road driving evaluations to the wider public. Supplemental data were also collected from a mail survey of driving schools nationwide. RESULTS: Based on the results of these efforts, a number of recommendations are presented for expanding the availability of on-road driving evaluations, specifically to help older adults make more responsible decisions about continuing or stopping driving, and more generally to help them drive safely longer. 相似文献
118.
种植业土地利用方式是关系农民增收的重要因素.采用主成分分析法,运用定量分析与定性描述的方法,全面分析了新疆 1978~2002年期间种植业土地利用变化的驱动因素.研究表明:影响新疆种植业土地利用规模的主要因素按影响力大小排列为科技进步、农业发展、农产品价格,而影响种植业结构变化的主要因素则有市场因素、粮食生产能力、产业政策.在此基础上,建立多元回归预测模型,为种植业土地合理利用提供评价依据,促进农民增收. 相似文献
119.
The sacred groves along the forest belts of south India, which were traditionally managed by village communities, are gradually disappearing. This study conducts an analysis of how this community‐based resource management institution has evolved over time and what socio‐economic factors have caused its gradual disintegration. Commercial agriculture, changing demographics and weak property‐rights systems are found to be some of the enabling factors. While the grass‐roots enthusiasm to save the sacred groves is still alive, government action is needed to strengthen the traditional village organizations, which are still perhaps in the best position to manage local resources. Several economic and financial incentive mechanisms at the local level that might lead to more efficient and equitable resource use outcomes are suggested. 相似文献
120.