基于事件法研究巨灾对我国上市公司的影响——以汶川8.0级地震为例

采用事件法分析了2008年汶川8.0级地震对四川省上市公司的影响。首先,选取建筑、电力、化工行业上市公司为样本,计算分析样本上市公司股票日平均异常收益率(AR)和累积异常收益率(CAR)的波动情况,然后对其进行检验;结果表明:地震灾害对不同行业上市公司的影响时间和程度都不尽相同,对建筑行业上市公司有正面影响,对电力行业和化工行业上市公司有较大负面影响。最后,总结分析巨灾对上市公司影响,借鉴国外经验,考虑我国巨灾风险管理国情,提出构建我国上市公司巨灾风险管理建议。     

上海市环境应急监测体系建设的思考

从机构和运行管理、使用技术和方法、硬件配置和监测能力、人员配置和培训演练四个片面介绍了上海市突发环境事件应急监测体系的现状。提出了完善上海市应急监测体系的设想,包括建立全市一盘棋的应急监测网络、加快新技术研发和方法标准化、加强装备配置和管理、加快应急监测队伍建设、建立和完善技术支持平台、加强后勤保障等。     

城市降雨屋面、路面径流水文水质特征研究

为研究城市硬质下垫面径流的水文过程与污染物浓度变化特征,对北京市2006年6-8月的4场降雨进行路面和屋面水文、水质过程同步分析.结果表明,径流曲线与降雨过程线形状类似,波动幅度相对较小,滞后于降雨过程线5～20 min,屋面径流系数在0.80～0.98之间;路面径流系数在0.87～0.97之间.径流污染物的浓度是由累积排放规律决定的,路面径流的污染物浓度高于屋面径流,径流中COD、TN、TP的浓度均超过地表水环境质量标准V类水要求.各类污染物之间的相关性均处于显著性水平R=0.1以上,屋面径流颗粒物与有机物和阴离子之间的相关关系较大(＞0.5),而与氮磷等营养物质的相关系数较小(＜0.5);路面径流中,TN、1P与颗粒物的相关性有所增加.径流中各类物质大多存在初期冲刷现象,并受到污染物种类、下垫面特征、降雨强度和雨型等因素的影响.SS初期冲刷现象较其它几类污染物更为明显,路面较屋面更容易形成初期冲刷,低强度降雨不容易形成有机物和营养物质的初期冲刷现象.控制初期径流污染是北京市径流管理的有效措施.     

Sensor design for saltwater ingress detection in high reliable all-electric deep sea actuators

Subsea oil and gas production relies on Xmas Trees which are mounted on boreholes. Xmas Trees are an arrangement of different valve types and sizes actuated by hydraulic, electro-mechanic or all-electric actuators. All these actuators sharing problems with saltwater ingress and the re-sulting increased wear. This paper investigates potential effects which can be measured after saltwater ingress. Extensive testing is executed and the investigated effects are used for novel sensor designs. These designs are evaluated regarding certain requirements and a resulting sen-sor design is proposed for industrialization. The resulting sensor can then be used to collect new important data to support optimal maintenance in the subsea industry.     

Age and spatial distribution of the world's oldest trees

Extremely old trees have important roles in providing insights about historical climatic events and supporting cultural values, yet there has been limited work on their global distribution and conservation. We extracted information on 197,855 tree cores from 4854 sites and combined it with other tree age (e.g., the OLDLIST) data from a further 156 sites to determine the age of the world's oldest trees and quantify the factors influencing their global distribution. We found that extremely old trees >1000 years were rare. Among 30 individual trees that exceeded 2000 years old, 27 occurred in high mountains. We modeled maximum tree age with climatic, soil topographic, and anthropogenic variables, and our regression models demonstrated that elevation, human population density, soil carbon content, and mean annual temperature were key determinants of the distribution of the world's oldest trees. Specifically, our model predicted that many of the oldest trees will occur in high-elevation, cold, and arid mountains with limited human disturbance. This pattern was markedly different from that of the tallest trees, which were more likely to occur in relatively more mesic and productive locations. Global warming and expansion of human activities may induce rapid population declines of extremely old trees. New strategies, including targeted establishment of conservation reserves in remote regions, especially those in western parts of China and the United States, are required to protect these trees.