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501.
Dang Z  Traas T  Vermeire T 《Chemosphere》2011,85(10):1592-1603
In a fish testing strategy, positive results of the fish short term reproduction assay (FSTR), often trigger a definitive test like the fish sexual development test (FSDT) or the fish full life cycle test (FFLC), entailing ethical and economic problems. This study analysed 137 studies encompassing 35 chemicals with different modes of actions (MOAs). Variability is quantified for MOA endpoints vitellogenin (VTG) and secondary sex characteristics (SSCs) as well as for apical endpoints. Two MOA endpoints could indicate estrogenic, anti-estrogenic, androgenic, anti-androgenic and steroidogenesis activities. Great variability, however, has been observed for chemicals with anti-androgenic and steroidogenesis activities, suggesting that TG229/230 may not be sensitive enough to detect these types of chemicals and may produce false negatives. Changes in apical endpoints like fecundity are not limited to endocrine disrupting chemicals (EDCs). Non-EDCs could induce the similar effects on these apical endpoints. If elucidating MOA is needed, targeted in vitro MOA tests are suggested. Positive in vitro MOA results trigger a definitive test, which could be used for confirmation of the MOA in vivo and for deriving a no observed effect concentration (NOEC). Based on positive MOA results of TG229, a definitive test such as the FSDT or the FFLC is still needed, because the current TG229 has limitation on the derivation of a NOEC. An extended TG229 with more power to detect reproduction effects, as recently proposed in the OECD test guideline program, would improve the possibility to derive a NOEC and increase its usefulness in risk assessment.  相似文献   
502.
瓦斯煤尘爆炸特性及传播规律研究进展   总被引:5,自引:3,他引:2  
概要介绍国内外的瓦斯爆炸和瓦斯煤尘混合物爆炸特性及传播规律研究进展,瓦斯爆炸研究主要集中在瓦斯爆炸压力、火焰、温度等特征参数、不同障碍物对瓦斯爆炸压力、火焰传播的影响以及分岔、拐弯等不同形状管道内的传播规律,而瓦斯煤尘混合物爆炸研究主要集中在瓦斯对煤尘爆炸的最小点火能、爆炸下限、最大爆炸压力等爆炸特性及传播规律的影响。对不同研究人员采用的主要研究指标、手段、方法和研究结论进行综合评述,同时也对爆炸事故人员伤害模型在国内外的研究状况进行讨论,最后指出目前存在的主要问题和下一步的研究方向。  相似文献   
503.
This paper examines the environment-income relationship in the context of the Environmental Kuznets Curve (EKC), and explores the possible role that factors like governance, political institutions, socioeconomic conditions, and education play in influencing this relationship. The results suggest that the EKC exists for carbon dioxide emissions for cross-country data over the period 1984–2002. However, there is nothing automatic about this relationship; policies designed to protect the environment may be responsible for this phenomenon. Two other significant findings are: one, countries with better quality of governance, stronger political institutions, better socioeconomic conditions and greater investment in education have lower emissions; and two, only around 15% of the countries in the dataset have reached income levels high enough to be associated with an unambiguous decline in emissions. The implications of these results are discussed within the context of the international environmental policy arena and the Kyoto Protocol. One of the main objectives of this paper is to bridge the gap between studies conducted on the EKC and developments in the international environmental policy arena. As a final note this paper emphasizes that one needs to connect the body of knowledge on the EKC hypothesis to the international environmental policy arena, despite the apparent difficulty of doing so. One hopes that future studies will further build on this line of thought.
Kuheli DuttEmail:
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504.
王颖  宋彦辉  李忠生  李新生 《灾害学》2012,27(3):31-33,44
对长安地裂缝金滹陀探槽工点Q3残积古土壤层原状样进行常规土工试验的结果显示:含水率、孔隙比相对裂缝带在其两侧均变小;密度、干密度在其两侧均变大;压缩模量在其两侧无明显变化;液限、塑限在其南侧无明显变化,而在其北侧变大;压缩模量相对裂缝带在次级地裂缝南侧变大,而在次级地裂缝北侧无明显变化;液限、塑限相对裂缝带在次级地裂缝两侧均变小.此试验结果为研究裂缝带的影响宽度提供了依据.  相似文献   
505.
随着经济全球化及网络通讯技术进步,服务外包已成为重塑世界产业格局的重要力量,其相关研究引起了学者的广泛关注。主要对服务外包产业发展规律和效应评估的相关研究进行综述。首先介绍了服务外包产生的主要理论观点,并梳理其演进过程及空间分布的研究进展;其次讨论服务外包效应评估的研究内容,其中发包国效应围绕就业、工资、生产力3个方面展开,承接国效应从经济、社会、技术外溢3个角度分析;第三,从理论和实证两个层面对效应评估方法进行了总结,重点基于投入产出表数据、研究报告数据及贸易数据归纳了测度外包水平的不同方法;在综合评述的基础上,展望了未来的研究趋向  相似文献   
506.
概述S-mark认证中的EMC要求及相关标准。以电磁炉为例,对日本电安法和电波法对EMC测试要求重新梳理了章节的测试条款,对标准规定不够详细的地方提出了解读意见,以供实验室检测和厂家认证参考。  相似文献   
507.
Wildman, Richard A., Jr. and Noelani A. Forde, 2012. Management of Water Shortage in the Colorado River Basin: Evaluating Current Policy and the Viability of Interstate Water Trading. Journal of the American Water Resources Association (JAWRA) 48(3): 411-422. DOI: 10.1111/j.1752-1688.2012.00665.x Abstract: The water of the Colorado River of the southwestern United States (U.S.) is presently used beyond its reliable supply, and the flow of this river is forecast to decrease significantly due to climate change. A recent interim report of the Colorado River Basin Water Supply and Demand Study is the first acknowledgment of these facts by U.S. federal water managers. In light of this new stance, we evaluate the current policy of adaptation to water shortages in the Colorado River Basin. We find that initial shortages will be borne only by the cities of Arizona and Nevada and farms in Arizona whereas the other Basin states have no incentive to reduce consumptive use. Furthermore, the development of a long-term plan is deferred until greater water scarcity exists. As a potential response to long-term water scarcity, we evaluate the viability of an interstate water market in the Colorado River Basin. We inform our analysis with newly available data from the Murray-Darling Basin of Australia, which has used interstate water trading to create vital flexibility during extreme aridity during recent years. We find that, despite substantial obstacles, an interstate water market is a compelling reform that could be used not only to adapt to increased water scarcity but also to preserve core elements of Colorado River Basin law.  相似文献   
508.
A three-dimensional/high-resolution transport model for persistent organic pollutants (POPs) has been developed for the East China Sea (ECS). The POPs model has four compartments (gaseous, dissolved, phytoplankton-bound, and detritus-bound phases) and includes processes for diffusive air-water exchange, phytoplankton uptake/depuration to POPs, decomposition of dissolved phase, vertical sinking of phytoplankton, detritus production by phytoplankton mortality, and vertical sinking and decomposition of detritus. The POPs model is coupled with an ocean circulation model that can reproduce the seasonal variation in physical variables to represent the advection and diffusion of POPs. We applied the POPs model to the polychlorinated biphenyl congener 153 (PCB 153) from the atmosphere and examined the behavior of PCB 153 in the ocean. The model showed a remarkable seasonal variability of PCB 153. Concentrations in the dissolved and particulate phases are high in winter (January-March) and low in summer (July-September). In coastal regions, where chlorophyll a concentration is high, horizontal and vertical distributions in the dissolved and particulate PCB 153 concentrations are strongly affected by phytoplankton uptake. The sensitivity experiments on the dynamics of PCB 153 suggested that a change of Henry’s law constant associated with water temperature is the major factor controlling the seasonal variability of PCB 153. The model-based yearly mass balance of PCB 153 in the ECS indicated that most of the atmospheric input (35.5 kg year−1) is removed by the horizontal advection outside the ECS (19.0 kg year−1) and accumulates to the sea bottom by vertical sinking (15.7 kg year−1). For comparison with PCB 153, we also conducted simulations for PCB 52, 101, and 180. The seasonal variations are similar to that of PCB 153. The mass balance of PCB 52 that has short half-life time and less hydrophobic property shows the different results compared with PCB 101, 153, and 180.  相似文献   
509.
新形势下环境监察执法探析   总被引:6,自引:0,他引:6  
环境监察执法是一种具体的、直接的环境保护执法行为。为更好地适应新形势下环境保护工作的要求,为节能减排服务,环境监察执法工作必须着力于"活、细、常",即变"单"为"活",变"粗"为"细",变"指"为"常"。  相似文献   
510.
混凝-超滤短流程工艺处理北方水库原水   总被引:1,自引:0,他引:1  
采用混凝-超滤膜短流程工艺对大伙房水库原水进行处理,考察其除污染性能和膜污染情况,并对该短流程工艺参数进行优化。结果表明,当利用超滤膜直接过滤原水时,膜污染较重,并且对污染物质的去除率较低;而采用混凝.超滤短流程工艺时,膜污染得到一定程度上的缓解;当絮凝剂投加量为7mg/L、膜清洗周期为30min时,对浊度、CODMn和UV254的去除率分别为95.61%、40.42%和37.12%,出水水质能够满足生活饮用水卫生标准。  相似文献   
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