首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 515 毫秒
1.
2.
3.
4.
Associations between positive thyroid autoantibodies and total blood mercury in women were evaluated using the National Health and Nutrition Examination Survey (NHANES), 2007–2008. Women are at increased risk for autoimmune disorders, mercury exposure has been associated with cellular autoimmunity and mercury accumulates in the thyroid gland. We used multiple logistic regression to evaluate the associations between total bloodmercury and thyroglobulin autoantibody antibody positivity and thyroid peroxidase autoantibody positivity in non-pregnant, non-lactating women aged 20 and older not currently using birth control pills or other hormone therapies, adjusted for demographic factors, menopausal status, nutrient intake and urine iodine (n = 2047). Relative to women with the lowest mercury levels (≤ 0.40 μg/L), women with mercury > 1.81 μg/L (upper quintile) showed 2.24 (95% CI = 1.22, 4.12) greater odds for thyroglobulin autoantibody positivity (ptrend = 0.032); this relationship was not evident for thyroid peroxidase autoantibody positivity. Results suggest an association between mercury and thyroglobulin autoantibody positivity.  相似文献   

5.
6.
7.
Predicting the transfer of radionuclides in the environment for normal release, accidental, disposal or remediation scenarios in order to assess exposure requires the availability of an important number of generic parameter values. One of the key parameters in environmental assessment is the solid liquid distribution coefficient, Kd, which is used to predict radionuclide–soil interaction and subsequent radionuclide transport in the soil column. This article presents a review of Kd values for uranium, radium, lead, polonium and thorium based on an extensive literature survey, including recent publications. The Kd estimates were presented per soil groups defined by their texture and organic matter content (Sand, Loam, Clay and Organic), although the texture class seemed not to significantly affect Kd. Where relevant, other Kd classification systems are proposed and correlations with soil parameters are highlighted. The Kd values obtained in this compilation are compared with earlier review data.  相似文献   

8.
9.
~~《中国人口.资源与环境》选题指南  相似文献   

10.
11.
12.
13.
关于《新疆21世纪议程〉.和可持续发展问题的思考   总被引:2,自引:0,他引:2  
一、新疆自然资源及社会经济发展现状 (一)丰富的自然资源 1.水资源 新疆全年水汽总量为13797亿t,降水总量约为2429亿t,占17.6%,使占全国土地面积1/6的新疆所得到的降水仅占全国降水总量的4%,降水的84%分布于山区,形成干旱区中“湿岛”,为绿洲发展提供生命之源。新疆地表水径流量884亿m~3,地下水可开采量252亿m~3,高山区分布了24479km~2冰川,蓄水量25836亿m~3,是巨大的“固体水库”。  相似文献   

14.
Massachusetts v. Environmental Protection Agency was the first Supreme Court opinion generated specifically as a response to the issue of anthropogenic CO2 emissions, alleging that Environmental Protection Agency's (EPA) failure to regulate is leading to environmental harms for plaintiffs. This essay examines the majority opinion of Justice Stevens and his use of presumption and burden of proof, within a logic of problematic integration, to construct “certainty” as a rebuttal to and rejection of the “uncertainty” offered by EPA. I examine how this strategically constructed rebuttal to “uncertainty” functions as a declarative act of “certainty,” advancing a proposition whose scientific, legal, or political acceptance could function as a tipping point away from the claims of “uncertainty” used by opponents on this contentious issue. Because of the court's influence, the implications of their “certainty” extend beyond the case and into the broader discussion of climate change science and environmental communication.  相似文献   

15.
Environment, Development and Sustainability - Time and again, climate change is a global phenomenon; intrinsically affects people and the environment more at the local and the global level when...  相似文献   

16.
研究表明VIC模型在西苕溪流域具有良好的适用性,特别是对汛期洪水的模拟。应用陆面水文模型VIC与区域气候模式PRECIS耦合,探讨了西苕溪流域未来洪水对气候变化的响应。结果表明:横塘村水文站月平均流量与月最大洪峰流量的关系较为密切,相关系数均在0.85以上,在一定程度上可以表征洪水的变化特征;基于PRECIS生成的气候情景,未来时期西苕溪流域洪水对气候变化的响应比较明显,尤其是汛期流量增加趋势较显著;结合P-Ⅲ型分布频率分析,西苕溪流域2021~2050年发生洪水极值事件的频率及量级都较基准期增大,且A2情景比B2情景相对更容易触发较大洪水,基准期50 a一遇洪水在未来两种情景下分别缩短为27 a一遇和32 a一遇,说明流域洪水对于气候变化的响应程度增大。  相似文献   

17.
可变下渗能力模型VIC是基于单元网格的分布式水文模型,易于与气候模式进行耦合,从而揭示气候变化对水循环的复杂影响,为分析气候变化情景下流域洪水的响应特征提供技术支撑。作为研究工作的第一步,构建了基于5 km×5 km网格分辨率的西苕溪流域VIC径流模拟模型。利用流域出口横塘村水文观测站1990~2000年日流量观测数据并结合西苕溪流域的汇流特点,采用Dag Lohmann汇流模型进行参数率定和验证。模拟结果表明:VIC模型对西苕溪流域日、年径流量的模拟值与观测值吻合良好,率定期和验证期的多年平均年径流相对误差Er分别为077%和343%,模拟日或月流量的确定性系数和Nash Suttcliffe系数都大于075,特别是对洪水年汛期流量过程的模拟,确定性系数均大于080,模型对洪水的模拟可信性较高  相似文献   

18.
Questioning the compatibility of economic growth and environmental sustainability, some scholars and activists call for a degrowth strategy. This idea presents an attack on the economic growth paradigm, and it has thus raised considerable attention. Yet, although many agree with questioning economic growth, a debate continues as to whether the term “degrowth” is (dis)advantageous in wider public communications. This debate, however, lacks empirical evidence. Here, we present two studies on how “degrowth” is perceived compared to other relevant terms. In Study 1, we show that “degrowth” elicits more negative affective and emotional reactions compared to “post-growth” and “prosperity without growth.” In Study 2, we find that the effects of labeling on attitudes and voting intentions toward a sustainable economy are relatively small. These initial results suggest that “degrowth” may evoke somewhat more negative emotional reactions than similar terms, but this may not have significant consequences. We discuss the results and draw implications for communication and further research.  相似文献   

19.
定位研究了25a来缙云山银木荷林物种组成及多样性在自然演替过程中的动态变化。结果表明,银木荷林维管植物物种由57种(隶属于24科,46属)减少到38种(隶属于19科,26属)。林下草本和层间植物逐渐消失,胸径大于7.5cm的乔木层树总胸断面积有所减少。尽管群落物种组成以及多样性发生改变,但是银木荷依然是优势树种,处于林冠层,而林冠亚层的白毛新木姜子、四川山矾、长蕊杜鹃逐渐增多,短刺米槠逐渐减少。群落乔木层4个α多样性指数都呈下降趋势,丰富度指数由2.98下降为1.99,Shannon-Wiener指数25a间减小了0.34,Simpson指数和Pielou指数变化都很小;β多样性分析结果显示,银木荷群落的物种差异很大。研究表明,25a间群落物种差异显著。揭示缙云山银木荷林自然演替过程中的物种组成和多样性变化规律,可为缙云山保护区及长江流域中上游亚热带常绿阔叶林的银木荷群落的管理提供一定的参考价值。  相似文献   

20.
定位研究了25 a来缙云山银木荷林物种组成及多样性在自然演替过程中的动态变化。结果表明,银木荷林维管植物物种由57种(隶属于24科,46属)减少到38种(隶属于19科,26属)。林下草本和层间植物逐渐消失,胸径大于75 cm的乔木层树总胸断面积有所减少。尽管群落物种组成以及多样性发生改变,但是银木荷依然是优势树种,处于林冠层,而林冠亚层的白毛新木姜子、四川山矾、长蕊杜鹃逐渐增多,短刺米槠逐渐减少。群落乔木层4个α多样性指数都呈下降趋势,丰富度指数由298下降为199,Shannon Wiener指数25 a间减小了034,Simpson指数和Pielou指数变化都很小;β多样性分析结果显示,银木荷群落的物种差异很大。研究表明,25 a间群落物种差异显著。揭示缙云山银木荷林自然演替过程中的物种组成和多样性变化规律,可为缙云山保护区及长江流域中上游亚热带常绿阔叶林的银木荷群落的管理提供一定的参考价值。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号