关于络合滴定的终点误差的研究

终合滴定是化学分析中的一个重要领域，它广泛应用于各生产部门和科学研究中，络合滴定的终点误差（TE）问题是关系到测定结果是否准确可靠性至涉及分析方法本身是否可靠的大问题，通过理论推导和试验验证，提出了除通常采用的计算方法外的几种络各滴定终点误差计算方法，使读者更进一步明确了有关终点误差的实质和计算运用。     

环境温度下SBR实现稳定部分亚硝化研究

采用SBR反应器建立了一套通过特定pH终值调控曝气停止点，以实现稳定部分亚硝化的策略，整个运行过程分为3个阶段，阶段Ⅰ启动亚硝化，阶段Ⅱ在稳定亚硝化的同时探索pH终值的设定规律，阶段Ⅲ采用pH终值设定规律实现稳定部分亚硝化，通过跨越夏、冬季（7~35℃）共148d的运行，考察SBR系统内有机物、氮素的转化规律，并分析不同温度（23、18、13℃）对部分亚硝化反应过程的影响.结果表明，在低DO（0.2~0.4mg/L）和MLSS为4000mg/L的条件下，控制pH终值为（7.73±0.02），使出水FA在0.5~1.2mg/L，可稳定部分亚硝化期间的出水NO₂^--N/NH₄⁺-N值在1~1.4之间，出水亚硝积累率（NAR）维持在85%以上，有机物去除率在60%以上.比氨氧化速率、比亚硝态氮氧化速率、比COD去除速率均随温度下降而降低，但降低趋势较缓，且反应均能稳定完成.     

Overcoming Endpoint Bias in Climate Change Communication: The Case of Arctic Sea Ice Trends

Unusually cold winters, a slowing in upward global temperatures, or an increase in Arctic sea ice extent are often falsely cast as here-and-now disconfirmation of the scientific consensus on climate change. Such conclusions are examples of “end point bias,” the well documented psychological tendency to interpret a recent short-term fluctuation as a reversal of a long-term trend. End point bias poses a challenge to those trying to communicate cross-decade climate warming trends. In this study, we demonstrate that exposure to misleading scientific information on FoxNews.com that evokes end point bias can affect the beliefs of liberals and moderates as well as conservatives. We also show that the leveraging-involving-visualizing-analogizing communication model can reduce the effects of endpoint bias among moderates and liberals at the same time as it dampens both the ideological and endpoint biasing of conservatives.     

土壤铜植物毒害的不同评价终点和室内外测定差别研究

本论文对山东陵县、湖南祁阳和浙江嘉兴3种性质差异较大的土壤上进行的室内外的土壤外源铜(Cu)的植物毒性试验结果进行了比较。结果发现3种室内评价终点(大麦根长、西红柿和小白菜苗期生物量)和田间植物(玉米、小麦、水稻和油菜产量)对土壤中Cu毒性的敏感性存在较大的差异。大麦根伸长和小白菜生物量法高估了土壤中Cu对田间小麦、玉米和水稻产量的毒害,而室内西红柿生物量法则低估了土壤中Cu对田间小麦、玉米和水稻产量的毒害。小白菜和田间油菜的敏感性接近,可以用室内小白菜苗期生物量作为土壤中Cu对田间油菜产量毒性评价的植物。当采用相同植物比较时,陵县小麦、祁阳玉米和嘉兴油菜的室内苗期值可以作为土壤Cu对相同田间植物产量的毒害作用(EC_(10))的评价指标。但是,室内苗期毒害指标会低估Cu对田间祁阳小麦和高估嘉兴水稻的毒害作用,说明土壤Cu植物毒害室内外测定的差别受土壤和植物的影响。     

A conceptual model for assessing ecological risk to water quality function of bottomland hardwood forests

Ecological risk assessment provides a methodology for evaluating the threats to ecosystem function associated with environmental perturbations or stressors. This report documents the development of a conceptual model for assessing the ecological risk to the water quality function (WQF) of bottomland hardwood riparian ecosystems (BHRE) in the Tifton-Vidalia upland (TVU) ecoregion of Georgia. Previus research has demonstrated that mature BHRE are essential to maintaining water quality in this portion of the coastal plain. The WQF of these ecosystems is considered an assessment endpoit—an ecosystem function or set of functions that society chooses to value as evidenced by laws, regulations, or common usage. Stressors operate on ecosystems at risk through an exposure scenario to produce ecological effects that are linked to loss of the desired function or assessment end point. The WQF of BHRE is at risk because of the ecological and environmental quality effects of a suite of chemical, physical, and biological stressors. The stressors are related to nonpoint source pollution from adjacent land uses, especially agriculture; the conversion of BHRE to other land uses; and the encroachment of domestic animals into BHRE. Potential chemical, physical, and biological stressors to BHRE are identified, and the methodology for evaluating appropriate exposure scenarios is discussed. Field-scale and watershed-scale measurement end points of most use in assessing the effects of stressors on the WQF are identified and discussed. The product of this study is a conceptual model of how risks to the WQF of BHRE are produced and how the risk and associated uncertainties can be quantified.     

利用模式动物秀丽线虫建立环境毒物毒性的评估研究体系

模式动物秀丽线虫(Caenorhabditis elegans)在环境科学与生态毒理学研究中发挥着越来越重要的作用,目前利用秀丽线虫已初步建立起较为完善的环境毒物毒性评估体系.该评估体系具体由如下一些指标构成:致死率、最长寿命与半数致死天数、细胞凋亡、个体发育、生殖、运动行为、乙酰胆碱酯酶活性、学习行为、记忆行为、转基因品系、突变体、基因表达模式.论文系统总结了近十多年来利用秀丽线虫进行环境毒物毒性评估的研究体系,并对各个指标的研究方法、研究现状、存在的问题及应用中需要注意的地方进行了讨论。     

基于危险化学品储存的区域生态环境风险评价

借鉴现有的生态风险评价方法,提出适合危险化学品储存的区域生态风险评价体系,即区域生态风险受体确定,评价终点选择,暴露途径和方式,暴露剂量分析与计算,风险表征以及区域生态风险管理对策等。研究结果表明:在有风模式中,鸟类的不可接受风险范围最远可达下风向7km,蛙类的不可接受风险最远可达下风向27km。大部分敏感点的蛙类急性暴露剂量都超标,处于不可接受风险水平;80%的敏感点的鸟类处于不可接受风险水平。根据风险评价结果,提出从防范措施、应急预案、环境监测和生态补偿4个方面制定区域生态风险管理措施。该区域生态环境风险评价研究为同类型区域生态环境风险评价提供借鉴作用。     

Avoidance test with Enchytraeus albidus (Enchytraeidae): effects of different exposure time and soil properties

Enchytraeids are ecologically relevant soil species and are commonly used in standardized toxicity tests. Their rapid reaction to a chemical exposure can be used as a toxicological measurement endpoint that assesses the avoidance behavior. The objectives of this investigation were to determine the effects of soil properties on the avoidance behavior of Enchytraeus albidus and to optimize the duration of avoidance test. The avoidance tests included (1) exposures in OECD artificial soil with standard or modified properties (pH, clay or peat content), and (2) exposures to copper chloride, cadmium chloride, and to the organic pesticides dimethoate and phenmedipham for different time periods. Results showed that alteration of OECD soil constituents significantly affected the avoidance behavior of enchytraeids, and that the 48-h exposure was the optimal duration of the test. Consideration of soil properties is important for selecting appropriate experimental design and interpreting the results of the enchytraeid avoidance test.     

基于斑马鱼的水生生态毒理学实验教学体系的构建

在我国现有的生态毒理学教学体系中,相对于理论教学,其实验教学体系的构建和实践相对滞后,阻碍了相关领域的人才培养。斑马鱼是国际上广受瞩目的小型模式鱼,本文在目前已成功开发并应用于科研的一系列斑马鱼毒性测试策略和方法的基础上,初步构建较为完整的水生生态毒理学实验内容和案例。虽然仅基于斑马鱼这一实验物种,但包括了致死效应、致畸效应、神经毒性、内分泌干扰效应、免疫毒性、遗传毒性等,涵盖不同生物学层面的多个毒理学终点,有助于充分训练学生的实验技能,巩固所学的理论知识。此外,在学生初步掌握上述实验手段的基础上,设置综合性或者设计性实验,可进一步培养学生的创造性思维和科研能力。本文对于现有的生态毒理学实验教学有一定的参考和借鉴意义。