氟对斑马鱼生殖毒性研究

为了探讨氟对鱼类的生殖毒性效应,以成年斑马鱼为试验对象,氟化钠暴露45 d和90 d后,运用组织切片观察斑马鱼性腺组织的发育情况,采用酶联免疫分析法测定性腺中雌二醇（Estradiol,E2）、卵黄蛋白原（Vitellogenin,VTG）和睾酮（Testosterone,T）的含量,并使用实时荧光定量PCR方法检测斑马鱼生殖相关基因的表达水平.结果显示：氟暴露会阻滞成年斑马鱼性腺发育,造成卵泡发育不良,精巢生精能力下降;同时降低雌性斑马鱼性腺中E2和VTG的含量,增加T的含量;雌性斑马鱼孕酮受体（Prg）和糖皮质激素受体（GR）基因相对表达量随氟浓度的增加呈先降后升的趋势,随着染毒剂量与时间的增加,雄激素受体（AR）基因相对表达量逐渐增加,而CYP19a基因相对表达量逐渐减少.雄性斑马鱼性腺中E2、VTG、T的含量及生殖相关基因表达的变化趋势则与雌性斑马鱼相反.综上所述,氟暴露可以通过影响斑马鱼体内性腺发育、E2、VTG、T含量及生殖相关基因表达来影响其生殖功能.实验结果可为进一步研究氟化物对水生动物的生殖毒性效应提供理论依据.     

BTEX在乙醇汽油和传统汽油污染地下水中的衰减行为对比

地下燃油储藏罐泄漏造成苯、甲苯、乙苯和二甲苯（BTEX）影响生态环境和公众健康的问题一直备受关注,随着乙醇汽油的推广使用,乙醇对BTEX修复策略的影响成为需要重视的新问题.为揭示乙醇汽油污染地下水中BTEX的衰减行为,本文通过室内两个独立砂槽投注实验和近3年的监测,对比了乙醇汽油和传统汽油中BTEX自然衰减和基于硫酸盐-硝酸盐补充的增强生物修复行为.结果表明,传统汽油BTEX自然衰减较快,乙醇汽油BTEX自然衰减较慢,一级衰减速率常数分别为0.0055~0.0329 d^-1和0.0045~0.0124 d^-1;苯衰减最快,其次为甲苯.补充硫酸盐和硝酸盐能促进生物修复,单独补充硫酸盐时其利用率为89.7%~92.9%,同时补充硝酸盐时硫酸盐利用被抑制,硝酸盐利用率为79.9%~87.2%.水位波动会促进BTEX溶解和迁移,增大质量通量.乙醇汽油不仅能消耗更多电子受体,使得BTEX衰减被抑制,而且可能会扩大水位波动引起的增溶效应.     

基于水库旱限水位动态控制的供水策略研究

为了克服现行水库旱限水位确定方法和功能定位上存在的不足,更好地为水库抗旱调度提供技术支持,通过结合供水系统水文干旱识别方法,用汛末蓄水量、干旱期设计来水量及供水规则计算干旱预警期。并根据实际来水逐月修改来水系列,对当年潜在干旱期和干旱预警期进行再计算,实现旱限水位的动态控制,由此提出了用“预警期/旱限水位”数对的形式(Td,DL)来表示的旱限水位动态控制方法。将旱限水位与限制供水策略相关联,用水库旱限水位作为触发水库限制供水的特征水位。并以水库累计缺水指数最小为目标,以限制供水系数为优化变量,建立水库进入干旱预警后的供水模拟-优化模型。以天津市于桥水库为实例研究,结果表明,旱限水位动态控制方法对水库干旱的预警不仅更加合理,且具有较好的可操作性;旱限水位与限制供水策略相关联,避免了潜在干旱期内水库出现程度更加严重的缺水,对不同蓄水条件下的限制供水系数进行分析,发现限制供水系数最优值一般取在0.5~0.75。     

基于FUZZY-AHP的危化品管道运输 安全等级综合评判模型与应用

为有效控制与降低危化品管道运输风险,以国家安全生产法和危化品输送管道安全管理规定为基础依据,与我国危化品管道运输现状相结合,建立以危化品管道运输安全等级为目标层的评价指标体系后,基于层次分析法(AHP)理论与模糊数学综合评价法(FUZZY),构建其综合评价模型。通过实例验证表明,该模型对危化品管道运输安全等级的确立科学且有效,所得结论对于提升危化品管道运输安全等级有较好的理论和实践指导作用。     

山岭隧道施工中塌方风险评估模型研究及应用

为评估隧道施工中塌方风险,以确定其可能性及严重程度作为2条主线。由文献调研并结合待评估隧道风险特征、施工现状、工程概况等建立塌方可能性评估指标体系,运用层次分析法(AHP)与多层次模糊综合决策确定塌方风险事件可能性等级,定性指标由专家评判确定对各可能性等级的隶属度,定量指标的隶属度以正态分布作为隶属函数求出;综合考虑多种事故后果类型,选用当量估计法确定塌方风险事件严重程度;最后基于风险矩阵法确定隧道塌方风险等级。将本模型应用于兴隆隧道1号斜井,经评估该斜井塌方风险等级为Ⅲ级,即较大风险,后续施工中须采取有效措施降低风险,减少风险可能导致的损失。     

Climate as a group level phenomenon: Theoretical assumptions and methodological considerations

Climate is a group‐level phenomenon that should be measured and studied at the group level. The group level has theoretical and methodological advantages over the individual level. In this paper, I theoretically review the assumptions in measuring climate at the individual and group levels and demonstrate that the group‐level assumptions are more adequate for climate research because of their influences in exposure to events, interpretation of events, and preservation of perceptions. Methodologically, I discuss advantages in group‐level climate measurement accuracy that are based on multiple evaluators of climate and I suggest group aggregation is an organizational form of “wisdom of the crowds.” Finally, I point to three topics that remain to be investigated to understand climate at the group level better. The first is use of variability measures to compensate for information that is lost in aggregation. The second is challenging the assumption that formal organizational structure defines the group boundaries. I suggest that other levels of analysis apply to group‐level climate measurement and demonstrate the use of informal, more natural groups as an additional level. Third, I point to recently developed statistical procedures that can aid the study of climate perception emergence over time.     

Effects of multitasking on operator performance using computational and auditory tasks

This study investigated the effects of multiple cognitive tasks on human performance. Twenty-four students at North Carolina A&;T State University participated in the study. The primary task was auditory signal change perception and the secondary task was a computational task. Results showed that participants' performance in a single task was statistically significantly different from their performance in combined tasks: (a) algebra problems (algebra problem primary and auditory perception secondary); (b) auditory perception tasks (auditory perception primary and algebra problems secondary); and (c) mean false-alarm score in auditory perception (auditory detection primary and algebra problems secondary). Using signal detection theory (SDT), participants' performance measured in terms of sensitivity was calculated as ?0.54 for combined tasks (algebra problems the primary task) and ?0.53 auditory perceptions the primary task. During auditory perception tasks alone, SDT was found to be 2.51. Performance was 83% in a single task compared to 17% when combined tasks.     

北京某污水处理厂污泥重金属污染特征、潜在生态风险及健康风险评价

连续采集了北京市某污水处理厂污泥,样品经过微波消解后利用ICP-OES测定重金属含量,同时,利用BCR连续提取分析方法分析了污泥中重金属赋存形态.在分析测定污泥中Pb、Zn、Cd、Cr、As、Ni、Cu 7种重金属含量及形态的基础上,开展了污泥重金属污染水平评价、潜在生态风险评价及健康风险评价.结果表明,污泥中重金属含量最高的是Zn,含量为930.08 mg·kg-1,残渣态及可提取态所占比例最高的元素分别是Pb和Ni,所占比例分别为80.86%及18.84%;污泥重金属综合污染指数为4.84,属重度污染;污泥重金属潜在环境综合风险指数为237.60,属极高生态风险.基于健康风险评价模型建立两条暴露途径,分别对儿童及成人进行健康风险评价,得出儿童非致癌指数及致癌指数分别为2.02×10-1和1.44×10-4,而成人非致癌指数及致癌指数分别为7.21×10-2和5.13×10-5.     

基于受体易损性分析的环境风险综合评价方法研究

针对我国现有环境风险评价体系中缺乏对自然环境、人工环境损失进行量化评价这一问题,在以往研究的基础上,建立了符合我国特点的受体易损性区划指标体系与量化模型,结合事故影响预测,建立了风险值计算方法,并提出了基于Bootstrap算法的环境风险可接受水平确定方法,由此构建了一套新的环境风险综合评价方法体系。     

Black Sea beaches vulnerability to sea level rise

Integrated Coastal Zone Management (ICZM) aims to promote sustainable management of coastal zones based on ecosystem and holistic management approaches. In this context, policies have to consider the complex interactions that influence the fragile equilibrium of coastal ecosystems. Beaches represent both valuable and vulnerable natural resources because of the various ecosystem services they provide and their sensitivity to climate change and sea level rise.We present the first comprehensive digital record of all Black Sea beaches and provide a rapid assessment of their erosion risk under different scenarios of sea level rise. Through the digitisation of freely available remote-sensed images on the web, we provide broad information on the spatial characteristics and other attributes of all Black Sea beaches (e.g. photo-based visual estimation of the sediment type, presence of coastal defences, urban development). These data have been assembled and stored in full Spatial Data Infrastructure (SDI) – allowing spatial queries, visualisation and data sharing – and are therefore particularly interesting to feed/supply web-GIS portals (coastal atlases) for visualisation purpose, spatial queries or spatial indicators calculations.The resulting Black Sea beaches database contains 1228 beaches, with a total coastline length of 2042 km with an area of 224 km². The majority of the Black Sea beaches have been found to have small widths (61% have maximum widths less than 50 m), whereas 47% of all beaches presented coastal defence schemes, suggesting an already serious beach erosion problem.The erosion risk of the Black Sea beaches was assessed through the comparison of their maximum widths with estimations of the sea level rise-induced retreat by an ensemble of six 1-D analytical and numerical morphodynamic models. Following more than 17,000 experiments using different combinations of wave conditions, beach sediment textures and slopes and 11 scenarios of sea level rise (up to 2 m), the means (best fits) of the lowest and highest projections by the model ensemble were estimated; these were then compared to the maximum widths of the Black Sea beaches. The analysis showed that sea level rise will have highly significant impacts on the Black Sea beaches, as for a 0.5 m sea level rise 56% of all beaches are projected to retreat by 50% of their maximum width. For a 0.82 m sea level rise (the high IPCC estimate for the period 2081–2100) about 41% are projected to retreat by their entire maximum width, whereas for 1 m sea level rise about 51% of all Black Sea beaches are projected to retreat by (drowned or shifted landward by) their entire maximum width, if the high mean of the model ensemble projections is used.Results substantiate the risk of beach erosion as a major environmental problem along the Black Sea coast, which therefore needs to be taken into account in any future coastal management plans, as a matter of urgency. As these scenarios consider only sea level rise, they are considered to be conservative. Although the present results cannot replace detailed studies, the database and projections may assist Black Sea coastal managers and policy makers to rapidly identify beaches with increased risk of erosion, valuate accordingly coastal assets and infrastructure, estimate beach capacity for touristic development purposes, and rapidly assess direct and indirect costs and benefits of beach protection options. They also provide the necessary inputs to advance discussions relevant to the Black Sea ICZM.