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971.
危化品企业在根据《危险化学品重大危险源辨识》(GB18218-2009)进行重大危险源辨识的过程中,有四个问题较难解决或处理,即危化品水溶液临界量的确定、重大危险源辨识物质法定范围的确定、部分物质临界量设置不合理、如何确定危险物质的存在量.针对这四个问题提出了相应的对策:对危化品水溶液,其临界量的确定可依据水溶液的主要危害特性,对照《危险化学品重大危险源辨识》(GB18218-2009)中的表2进行确定;对不属于危险化学品,但又具有易燃、易爆、有毒特性的危险物品,如果其数量超过类似危化品的临界量,建议参照危化品重大危险源进行相应的安全管理;对于危险物质临界量的确定,建议按照危险源可能造成的事故危害后果或范围推算确定;对于危化品实际数量的确定,建议按照企业可能存在的最大量或设计量进行计算.  相似文献   
972.
Bushmeat markets exist in many countries in West and Central Africa, and data on species sold can be used to detect patterns of wildlife trade in a region. We surveyed 89 markets within the Cross–Sanaga rivers region, West Africa. In each market, we counted the number of carcasses of each taxon sold. During a 6‐month period (7594 market days), 44 mammal species were traded. Thirteen species were on the International Union for Conservation of Nature (IUCN) Red List or protected under national legislation, and at least 1 threatened species was traded in 88 of the 89 markets. We used these data to identify market groups that traded similar species assemblages. Using cluster analyses, we detected 8 market groups that were also geographically distinct. Market groups differed in the diversity of species, evenness of species, and dominant, prevalent, and characteristic species traded. We mapped the distribution of number of threatened species traded across the study region. Most threatened species were sold in markets nearest 2 national parks, Korup National Park in Cameroon and Cross River in Nigeria. To assess whether the threatened‐species trade hotspots coincided with the known ranges of these species, we mapped the overlap of all threatened species traded. Markets selling more threatened species overlapped with those regions that had higher numbers of these. Our study can provide wildlife managers in the region with better tools to discern zones within which to focus policing efforts and reduce threats to species that are threatened by the bushmeat trade. Mapeo de Sitios Críticos para Especies Amenazadas Comercializadas en Mercados de Vida Silvestre en la Región de los Ríos Cross‐Sanaga  相似文献   
973.
Abstract: To understand how a highly contentious policy process influenced a major conservation effort, I examined the origins, compromises, and outcomes of the Alaska National Interest Lands Conservation Act of 1980 (ANILCA) for the Tongass National Forest. Tongass wilderness designation was among the most controversial issues in the ANILCA debate, and it faced strong opposition from influential lawmakers, land managers, and Alaska residents. To investigate the influence of this opposition on Tongass conservation outcomes, I conducted a gap analysis of Tongass reserves and a policy analysis of the ANILCA debate and traced the influence of specific interests through the amendments, negotiations, and resulting compromises needed to enact ANILCA. Overall, I found that Tongass reserves comprise a broadly representative cross‐section of ecosystems and species habitats in southeastern Alaska. Redrawn reserve boundaries, industry subsidies, and special access regulations reflected compromises to minimize the impact of wilderness conservation on mining, timber, and local stakeholder interests, respectively. Fragmentation of the Admiralty Island National Monument—the most ecologically valuable and politically controversial reserve—resulted from compromises with Alaskan Native (indigenous peoples of Alaska) corporations and timber interests. Despite language to accommodate “reasonable access” to wilderness reserves, ongoing access limitations highlight the concerns of Alaska residents that opposed ANILCA several decades ago. More broadly, the Tongass case suggests that early and ambitious conservation action may offset strong political opposition; compromises needed to establish key reserves often exacerbate development impacts in unprotected areas; and efforts to minimize social conflicts are needed to safeguard the long‐term viability of conservation measures.  相似文献   
974.
Abstract

The objective of this paper is to investigate the relationships among rural-urban migration, rural household income and sustainable development in rural areas of China. The typical case study is done and 288 questionnaires are collected from five villages in Hebei and Guangxi provinces, China. The migration and remittance status, household income and sustainable development of rural areas are analyzed on the basis of questionnaires. Rural-urban migration is becoming a part of routine life in rural areas. And remittance is an important component in rural household income. Rural-urban migration increases the arable land area per labor, which releases the tight human-land relationship in villages. In total, the migration increases the rural household income and accelerates the sustainable development of rural areas.  相似文献   
975.
针对1970年以来1400多起重、特大煤矿事故,应用统计分析方法,探讨了煤矿重、特大事故的时间规律以及不同事故类型与死亡人数之间的关系,发现重、特大煤矿事故与月份、每天不同时间段等有一定相关.每年11、4、3、5、6等月份重、特大事故较多,2月份事故次数最少(Asymp Sig=0.018),时间上重、特大事故高峰时段主要集中在9:00-13:00(Asymp Sig=0.000).自70年代以来单次事故死亡人数没有明显减少,不同事故类型与死亡人数有明显不同(Asymp Sig=0.000),瓦斯事故、煤尘事故、火灾、水灾、煤与瓦斯突出等单次影响较大,事故的时间规律在日期上显现不明显(Asymp Sig=0.262).预防重、特大事故应尤其注意相应的时间段和相应的事故类型.  相似文献   
976.
Abstract:  Freshwater ecosystems are declining in quality globally, but a lack of data inhibits identification of areas valuable for conservation across national borders. We developed a biological measure of conservation value for six species of Pacific salmon ( Oncorhynchus spp.) in catchments of the northern Pacific across Canada, China, Japan, Russia, and the United States. We based the measure on abundance and life-history richness and a model-based method that filled data gaps. Catchments with high conservation value ranged from California to northern Russia and included catchments in regions that are strongly affected by human development (e.g., Puget Sound). Catchments with high conservation value were less affected by agriculture and dams than other catchments, although only 1% were within biodiversity reserves. Our set of high-value areas was largely insensitive to simulated error, although classification remained uncertain for 3% of catchments. Although salmon face many threats, we propose they will be most likely to exhibit resilience into the future if a complementary mosaic of conservation strategies can be proactively adopted in catchments with healthy salmon populations. Our analysis provides an initial map of where these catchments are likely to be located.  相似文献   
977.
基于Landsat遥感影像热红外波段数据,利用大气校正法反演地表水热因子中的地表温度值,基于Landsat遥感影像可见光波段,从生物地球物理效应角度提取下垫面地表扰动类型和4个生物物理参数(光合植被覆盖度,Fractional Cover of Photosynthetic Vegetation,fPV;土壤湿度监测指数,Soil Moisture Monitoring Index,SMMI;增强型裸土指数,Enhanced Bare Soil Index,EBSI;归一化不透水面指数,Normalized Difference Impervious Surface Index,NDISI),借助叠加分析、相关分析和回归分析,定量分析了河北省迁安市马兰庄镇地表热环境时空异质性特征并可视化,以及4个生物地球物理参数的响应规律.结果表明:矿业用地地表温度最高,属热岛效应聚集区;地表下垫面扰动类型以及4个驱动因子的时空变化,导致研究区夏季午间地表热环境异质性较大,且5期影像下垫面地表温度均呈现出工矿用地>居民地>耕地>林地>水域的分异特征;单因素回归分析表明,fPV和SMMI指数与归一化地表温度(Normalized Land Surface Temperature,NLST)呈线性负相关(P<0.01),EBSI和NDISI与NLST呈线性正相关(P<0.01);多元回归分析表明,利用4个生物物理参数综合考量地表热环境异质性,可全面反映下垫面生物物理参数与地表温度的真实关系,且5期影像与LST呈负相关关系的SMMI回归系数均大于fPV,说明地表温度的下降与土壤湿度的增加有明显的关系;与LST呈正相关关系的EBSI回归系数均大于NDISI,说明地表温度的上升与裸土的增加有明显的关系.研究结果可为矿业密集区地表热环境异质性的评估和优化提供定量参考.  相似文献   
978.
经济发达地区土地可持续利用主要矛盾及其成因分析   总被引:8,自引:0,他引:8  
本文从阐述土地利用的主要矛盾特征入手,分析了经济发达地区土地利用矛盾的自然成因及战略偏差、结构偏差及利益偏差等深层实质,提出了解决我国尤其是经济发达地区日益尖锐的土地利用矛盾以及实现土地资源可持续利用的根本途径。  相似文献   
979.
从多角度分析新疆于田县50多年来的人口变化状况,其变动由3个波峰和3个波谷组成。增长率最高峰为1984年的34.13‰。最低峰是1964年的-2.29‰。两者相差36.42‰。形成人口高增长率的因素主要是社会稳定、医疗条件改善、文化大革命及政策;而瘟疫流行、自然灾害、人口惯性及政策控制了其增长。同时,由于宽松的少数民族生育政策。其人口控制和变化比发达地区滞盾一个时段.并亵现出偏远、自给自足地区受外界干扰少——一种典型封闭系统的人口变化特征。各类人口模式的变化都表明于田县人口变化已趋于一个较为合理的增长。为该县的经济和社会的持续发展提供了客观可能性。  相似文献   
980.
Abstract:  For many regions worldwide, multiple and often contrasting biogeographic classifications exist that are derived from a variety of taxa and techniques. This presents a challenge for managers who must choose appropriate large-scale spatial frameworks for systematic conservation planning. We demonstrate how systematically collected community data can be used to evaluate existing biogeographic classifications, identify the most appropriate metric for biogeographic patterns seen in other taxonomic groups, and develop an independent biogeographic classification scheme for systematic conservation planning. We evaluated 6 existing biogeographic classifications for New Zealand's nearshore marine environment with community-similarity metrics derived from abundance and presence–absence data for macroalgae (107 species) and mobile macroinvertebrates (44 species). The concordance between community metrics and the previous classifications was high, as indicated by a high multivariate classification success (CS) (74.3–98.3%). Subsequently, we carried out an independent classification analysis on each community metric to identify biogeographic units within a hierarchical spatial framework. The classification derived from macroalgal presence–absence data achieved the highest CS and could be used as a mesoscale classification scheme in which 11 regional groupings (i.e., bioregions) (CS = 73.8–84.8%) are nested within northern and southern biogeographic provinces (CS = 90.3–98.7%). These techniques can be used in systematic conservation planning to inform the design of representative and comprehensive networks of marine protected areas through evaluation of the current coverage of marine reserves in each bioregion. Currently, 0.22% of the territorial sea around mainland New Zealand is protected in no-take marine protected areas in which 0–1.5% of each bioregion represented.  相似文献   
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