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71.
无人机热红外支持下的城市微尺度热环境模拟   总被引:1,自引:1,他引:0  
随着人们对生活舒适度、身体健康要求的进一步提高,微小尺度的热环境状况日益受到关注.地表温度场模拟是研究城市微小尺度热环境的关键,采用地面有限实测资料很难满足不同下垫面地表温度模拟的精度需求.针对这一问题,本研究利用无人机搭载热红外成像仪获取南京市江宁区某大学校园内典型区域夏秋两季的地表温度数据,通过ENVI-met和PALM-4U两个数值模拟模型模拟研究区地表温度,并结合实测数据对不同地表类型及阴影遮挡下的模拟精度进行误差分析.结果表明,数值模拟结果与真实结果较为接近,能够用于高空间精度的城市微热环境研究中;模型对人造地表的模拟效果均优于自然地表,对空旷处地表的模拟效果优于非空旷处地表;两个模型均能较好模拟存在建筑物遮挡下的地表温度,但在植被遮挡下PALM-4U则无法达到ENVI-met的效果,综合模拟结果显示ENVI-met在城市微热环境模拟上的适用性优于PLAM-4U.本研究可为城市微尺度热环境高分辨率遥感研究提供参考.  相似文献   
72.
Long-term population declines have elevated recovery of grassland avifauna to among the highest conservation priorities in North America. Because most of the Great Plains is privately owned, recovery of grassland bird populations depends on voluntary conservation with strong partnerships between private landowners and resource professionals. Despite large areas enrolled in voluntary practices through U.S. Department of Agriculture's Lesser Prairie-chicken (Tympanuchus pallidicinctus) Initiative (LPCI), the effectiveness of Farm Bill investments for meeting wildlife conservation goals remains an open question. Our objectives were to evaluate extents to which Conservation Reserve Program (CRP) and LPCI-grazing practices influence population densities of grassland birds; estimate relative contributions of practices to regional bird populations; and evaluate percentages of populations conserved relative to vulnerability of species. We designed a large-scale impact-reference study and used the Integrated Monitoring in Bird Conservation Regions program to evaluate bird population targets of the Playa Lakes Joint Venture. We used point transect distance sampling to estimate density and population size for 35 species of grassland birds on private lands enrolled in native or introduced CRP plantings and LPCI-prescribed grazing. Treatment effects indicated CRP plantings increased densities of three grassland obligates vulnerable to habitat loss, and LPCI grazing increased densities of four species requiring heterogeneity in dense, tall-grass structure (α = 0.1). Population estimates in 2016 indicated the practices conserved breeding habitat for 4.5 million birds (90% CI: 4.0–5.1), and increased population sizes of 16 species , totaling 1.8 million birds (CI: 1.4–2.4). Conservation practices on private land benefited the most vulnerable grassland obligate species (AICc weight = 0.53). By addressing habitat loss and degradation in agricultural landscapes, conservation on private land provides a solution to declining avifauna of North America and scales up to meet population recovery goals for the most imperiled grassland birds.  相似文献   
73.
自1938年美国首先颁布管控化学品的法律以来,健康风险评估逐步发展,各个国家和地区相继颁布文件,并已形成较为完善的评估框架.由于在化学品健康风险评估的过程中,存在大量收集引用的数据及信息,因此数据质量评估是保证风险评估结果可信的关键.目前为止美国环保署(environmental protection agency,EPA)和欧盟《化学品的注册、评估、授权和限制》(regulation concerning the registration,evaluation,authorization and restriction of chemicals,REACH)法规均对数据质量评估方法进行了详细的规定.两个地区均采用数据评分(1—4)与证据权重(weight of evidence,WOE)(1/2)相结合的评估方法,不同之处在于欧盟更侧重于对数据整体的相关性、可靠性和充分性进行评估和打分,U.S EPA则更为细致具体,其侧重于不同情境下的数据分组分析,根据不同的评分领域和指标,规定高置信度、中置信度、低置信度和数据不可接受的标准.通过总结对比欧盟及美国的数据质量评估方法,建议我国采用数据打分与证据权重相结合的定量评估方法,并明确规定不同情景下不同数据来源的打分规则和标准,使数据质量评估过程系统化.  相似文献   
74.
为研究体外培养的人神经胶质瘤U251细胞(human U251glioma cells)铅暴露后基因表达的改变,分析脑中差异表达基因,探讨铅暴露与神经毒性之间的关系,使用浓度为400μg·mL-1乙酸铅暴露U251细胞8h和24h,设置空白对照,提取RNA.应用基因芯片方法寻找差异表达基因,芯片扫描结果经归一化处理,设定Ratio值<0.5或≥2.0为表达有差异基因.结果表明铅暴露U251细胞导致2840条基因差异表达,暴露8h和24h皆上调表达的基因有92条,皆下调表达的基因有85条,其中132条基因在脑中表达;通过与数据库资料比对,109条基因与其在脑表达情况一致,23条基因不一致(15条基因高表达,8条基因低表达).从实验结果可以看出铅暴露能够导致U251细胞基因表达改变,抑制细胞增殖和迁移,促进细胞凋亡,负调控T细胞免疫活性.导致与神经发生、细胞骨架形成相关基因表达下调,神经保护能力下降,铅暴露可能与神经变性疾病及退行性疾病发生有关.  相似文献   
75.
通过对贵州喀斯特地区乌江流域河水中溶解态铀的地球化学研究 ,定量评估了乌江河水中溶解态铀的浓度及河水中溶解态铀进入长江的通量 ( 1 4 74× 1 0 2 mol/a)。结果表明 :乌江流域溶解态铀主要来源于碳酸盐岩风化 ,人类活动对乌江河水中溶解态铀的影响很小。  相似文献   
76.
本文对近年文献报导中水、食品和人体中的~(234)U和~(238)U含量,比活度比值的调查结果,并估算出了人体所受的内照射剂量,作了评述,引用文献19篇,表格14张.  相似文献   
77.
Previous research on territoriality suggests that territorial intrusion is associated with particular territorial demarcations. In the present study the use of territorial displays involving symbolic barriers, actual barriers, detectability, traces and social climate is related to the territorial intrusion of residential burglary. The five classes of territorial displays were assessed for a total of 306 burglarized houses on burglarized blocks, non-burglarized houses on burglarized blocks, and non-burglarized houses on non-burglarized blocks. After the data were reduced through factor analysis, multiple regression analysis revealed that burglarized houses differed from non-burglarized houses on non-burglarized blocks on four of the five classes of territorial displays. In general, burglarized houses had salient public territorial qualities: cues of openness and unoccupied appearance. In contrast, the non-burglarized houses had salient secondary or primary territorial qualities: territorial markers communicating privacy and individuality. In addition, non-burglarized houses had greater visual contact with neighboring houses.  相似文献   
78.
International EIA activity has two origins. First, there is increasing concern over conflict between developmental and environmental interests within the economic development system. Second, EIA appeals to international agencies and governments as a well-defined, internally integrated procedure and planning tool. EIA activities involve political, institutional, and technical motivations and goals for the international bodies and the governments of countries receiving aid. Three criteria may be used to evaluate international EIA from the perspective of policy makers and administrators in the countries: political support, institutional strengthening, and technical capability. This paper reviews the influence of the United Nations system and of some multilateral and bilateral development assistance agencies in promoting EIA in developing countries. The extent the nature of the influence donors have on EIA in developing countries is shaped as much by the interests and organizational characteristics of the donors as by the needs and priorities of the recipients.  相似文献   
79.
Institutions managing the Alaska road,rail, airport, and marine highwaytransportation system and the pipelinecorridor are evaluated for reactions toevidence of climate change. Long-termclimate warming is not a formal criterionin the decisional process of the stateDepartment of Transportation and PublicFacilities for road and airport projects,which have a short (15–25 year) life span,but is taken into account for bridgeconstruction (50–75 year life). Short- tomid-term climate effects are considered inareas with discontinuous permafrost andaffect routing, roadbed construction, andmaintenance decisions. National standardsare amended with Alaska-specific practicesfor unique cold-weather conditions.The Federal/State Joint Pipeline Office(JPO), responsible for monitoring ofpipeline safety under the federal lease andstate grant, in 2001 developed additionalstipulations to mitigate permafrost thawingand slope instability, including a `watchlist' of 200 wobbling VSMs on theTrans-Alaska Pipeline. This action appearsmore responsive to climate change effectsthan that of any other arctic institutionstudied. It can be attributed to thespecific authority of the JPO to monitorgeotechnical conditions at present and inthe future.In general, agencies tended to adoptincremental responses to evidence ofclimate change.  相似文献   
80.
美国环境管理体系中联邦与地方政府角色透视   总被引:4,自引:0,他引:4  
自美国环境保护局(EPA)成立以来,美国各州的环境执政体制产生了巨大的变化,取得了卓越的成绩.美国的环境执政体制从分权的、由州驱动的体制演变为自上而下、技术强制、联邦驱动的体制.近几年该体制更加分权化,各州的作用更为强大;引入了市场力量,加强了环境保护力度,成本竞争力亦得到改善.自上而下/技术强制的体制和以非集权化/市场为主的体制有其各自的优缺点.笔者将试图阐明环境保护体制的良好运转同时需要来自这2种方式的元素.  相似文献   
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