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排序方式: 共有1513条查询结果,搜索用时 125 毫秒
831.
Gull eggs have been used to monitor contaminants in many parts of the world. The Seabird Tissue Archival and Monitoring Project (STAMP) is a long-term program designed to track trends in pollutants in northern marine environments using seabird eggs. Glaucous and glaucous-winged gull (Larus hyperboreus and Larus glaucescens) eggs collected in 2005 from seven Alaskan colonies were analyzed for organic contaminants. Concentrations ranged from below detection limits to 322 ng g−1 wet mass in one egg for 4,4′-DDE and differed among the samples collected in the Gulf of Alaska and Bering and Chukchi Seas. Chick growth and survival rates may be affected by the contaminant levels found in the eggs, but the eggs should be safe for human consumption if they are eaten in small quantities. STAMP plans to continue collecting and banking gull eggs for future real-time and retrospective analyses.  相似文献   
832.
Long-term safety assessments for geological disposal of radioactive waste in Switzerland involve the demonstration that the annual radiation dose to humans due to the potential release of radionuclides from the waste repository into the biosphere will not exceed the regulatory limit of 0.1 mSv. Here, we describe the simple but robust approach used by Nagra (Swiss National Cooperative for the Disposal of Radioactive Waste) to quantify the dose to humans as a result to time-dependent release of radionuclides from the geosphere into the biosphere. The model calculates the concentrations of radionuclides in different terrestrial and aquatic compartments of the surface environment. The fluxes of water and solids within the environment are the drivers for the exchange of radionuclides between these compartments. The calculated radionuclide concentrations in the biosphere are then used to estimate the radiation doses to humans due to various exposure paths (e.g. ingestion of radionuclides via drinking water and food, inhalation of radionuclides, external irradiation from radionuclides in soils). In this paper we also discuss recent new achievements and planned future work.  相似文献   
833.
活性污泥总DNA提取方法的比较   总被引:1,自引:0,他引:1  
从处理某制药废水的MBR反应器中采集活性污泥,评价不同DNA提取方法对其总DNA提取效率的影响。DNA提取分细胞裂解和DNA纯化2步,对细胞裂解比较了珠磨匀浆法、反复冻融法、十二烷基磺酸钠(sodium dodecyl sulfate,SDS)裂解法等7种方法;对DNA纯化比较了酚/氯仿纯化法和胶回收纯化法。结果表明,SDS裂解法、酚氯仿纯化法最优。通过条件优化实验,确定SDS裂解酚/氯仿纯化法在污泥量1.1 g,10 000 r/min离心5 min的操作条件下,获得的DNA产量(10 774 μg/g泥重)和纯度(OD260∶OD280=1.84)等综合指标最好。  相似文献   
834.
The article establishes the patterns of urban snow disaster system and disaster chain based on the theory of regional disaster system. The patterns indicate that urban snow disaster is exacerbated mainly through the traffic system. In addition, the paper sets up the vulnerability assessment index system and synthetically vulnerability assessment model of urban snow disaster which are mainly based on traffic system, and applies them in Chenzhou City. The results of assessment indicate that obvious geographical differences exist in the vulnerability of snow disaster bearing bodies: vulnerability of Chenzhou section of the Beijing-Zhuhai expressway is the highest in Chenzhou City, and the southeastern counties are more vulnerable than the northwest region. Furthermore, according to the snow disaster vulnerability dynamic process analysis, the vulnerability of Chenzhou City obviously increased in 2008 winter compared with that in 2007. Finally, the paper presents some suggestions for the locations of the emergency commands and the reserves of relief materials based on the evaluation results, and points out that disaster monitoring and relevant technical level should be strengthened for the minimization of traffic system's vulnerability.  相似文献   
835.
Several community gardens have been developed in Edinburgh over the past five years, which reflects renewed interest in “grow your own” projects, and the recognition of the associated environmental and social health benefits they provide. Community gardens have been included in a range of policy documents at national and local levels, acknowledging their contribution to sustainable food systems, health and well-being and environment and biodiversity. This research explores how public policy influences community garden practice and, reflexively, how organisations running community gardens in the third sector are represented in public policy frameworks. A mixed methodology of desk-based research of policy documents, associated reports and academic literature; and informal interviews with community gardens staff and organisers was utilised. It was found that while community gardens are represented in policy, at a national level the framing of community gardens and related food growing projects as “alternative” hinders their full potential. Community gardens fulfil a wide range of policy goals, particularly in the health, social capital and well-being sectors which can minimise their capacity to contribute to local food production in a substantial way. It is proposed that community gardens could be normalised by promoting gardens in visible locations in neighbourhoods and within local plans; and through reflexive strategic and community action utilising a reasoning backwards approach to planning and funding.  相似文献   
836.
Food waste is an inevitable type of waste in every city, and its treatment technology evolves with time. Due to the high organic content and high biodegradability of food waste, anaerobic digestion becomes a commonly accepted treatment method to deal with it. This review article summarizes key factors for anaerobic digestion and provides useful information for successful anaerobic digestions. Reasonable temperature and pH are essential for a successful and productive anaerobic digestion process. A good inoculum to substrate ratio triggers a profitable food waste digestion. Good mixing and small particle sizes are important factors too. In addition, the pros and cons of different reactors to food waste digestion are highlighted. Moreover, co-digestion of food waste with animal manures, sewage sludge, and green waste were introduced.  相似文献   
837.
事实再次证明,单纯由政府主导的食品安全监管模式已无法满足人们对于食品安全的消费需求。政府和市场在食品安全风险治理中出现的政府公权和市场私权的"双重失灵",迫切需要社会组织的参与。本文通过深度访问和问卷调查的形式,基于主成分分析方法将影响食品行业社会组织参与食品安全风险治理能力的影响因素指标融合为互不相关的综合指标,并由此构建了多元线性回归模型,研究了影响食品行业的社会组织参与食品安全风险治理能力的主要因素。研究结果表明,社会组织的公信力、与政府的关系、政府支持力度、社会组织的信息公开程度、专职人员的数量与质量等因素与其参与治理能力存在较强的正相关;社会组织法定代表人年龄、现职国家机关公务人员在组织内担任职务的比例与其参与治理的能力存在较高的负相关。因此,社会组织在食品安全的风险治理中是否能发挥自身独有的优势,弥补政府和市场在食品安全风险中的双重失灵,内在地取决于社会组织的外部环境、内部治理结构与内部管理水平。构建具有中国特色的食品安全社会共治体系亟需逐步完善社会组织的立法,明确社会组织的法律地位,确保社会组织在法律框架下按照各自的章程自主性地开展的各种活动,政府在法律框架下履行支持社会组织发展的职能力度;同时优化内部人员结构,建设具有数量充足、能力结构基本完备的工作人员队伍,并依据改革要求,优化法定代表人的结构,建立诚信信息服务平台,提升自身的社会公信度,由此保障社会组织在参与食品安全风险治理过程中的独立性,发挥自身专业性、自治性等优势。  相似文献   
838.
基于复杂网络的台风灾害演化系统风险分析与控制研究   总被引:2,自引:0,他引:2  
基于复杂网络理论,提出了一种针对自然灾害演化系统的风险分析与控制的思路与方法。以"莫拉克"台风为例,构建了包含30个危机事件与39条连接边的台风网络演化模型;采用网络节点的出入度、子网节点数和包含节点的支链数进行风险分析,并确定关键节点,进一步提出断链方案和控制建议。结果表明:狂风、暴雨、洪水、山体滑坡、泥石流、交通堵塞和村庄毁坏等事件风险较大,是台风灾害系统的关键节点。据此提出建议:提高城市排水系统运行能力,加强交通系统监管和调度力度,启动农村人员安置和灾后重建预案。  相似文献   
839.
萧凌波  黄欢  魏柱灯 《灾害学》2012,(1):101-106
以《清实录》等清代档案文献为主要历史信息源,挑选华北地区清代盛期(1743-1744年)和晚期(1876-1878年)分别发生的两次典型旱灾,对灾害气候背景和灾情、政府措施(特别是政府主导的跨区粮食调度)、社会后果(人口迁徙和动乱)等信息进行整理并分别对比,可以发现1743-1744年旱灾期间政府的粮食调度体现出粮食数量大、来源渠道广、调度效率高等鲜明特点,并取得了良好的社会效果;而1876-1878年旱灾则反之,粮食数量及来源有限,且转运效率极低,由此引发严重社会后果。这种转变,发生在主要余粮产区农业凋敝、南北粮食运道(大运河)阻断、漕运及仓储制度衰败的时代背景之下,重灾区空间分布带来的交通通达性差异,也在客观上影响了粮食调度的效率。  相似文献   
840.
地震与台风之间的灾害链问题是一个重要的灾害学问题。通过对2011年日本东北9.0级地震和塔拉斯台风灾害链的讨论,使地震-台风灾害链更具事实基础。另外还重点对地震-台风灾害链的成因做了进一步的讨论。  相似文献   
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