基于模糊熵和非对称贴近度的安全预警研究

针对道床漏泄严重导致道砟电阻和分路电阻发生变化、继而引起"红光带"与分路不良故障的问题,以ZPW-2000 A轨道电路为例,建立预警指标体系。采用模糊模式识别法对轨道电路状态进行预警。首先,计算各预警指标的隶属度函数和隶属度矩阵,利用模糊熵理论确定各预警指标的权重;其次,采用非对称贴近度原则对预警决策进行识别,以判决系统所属安全等级;最后,以长沙电务段新开铺站为例进行实例验证。结果表明,基于模糊非对称贴近度的轨道电路分路不良预警是可行的,其对轨道电路的安全等级划分更精细,故障预警更精确。     

湖南郴县千里山花岗岩的岩石学特征

千里山花岗岩是一个与W、Sn、Mo、Bi多金属矿床有关的多期多阶段岩浆侵入体。燕山晚期的花岗斑岩,其矿物学、岩石学及地球化学等各项特征均与燕山早期花岗岩及其衍生岩脉的特征不相同,W、Sn、Mo、Bi矿化与早期花岗岩体有关而与晚期花岗斑岩无成因联系,主体期花岗岩应属改造型,其成岩温度约在700℃±,压力约为1千巴,fo_2=10~(-15.5)～10~(-17.0),fH_2o=135～815巴,有利于矽卡岩的形成。     

民国初年灾荒史研究综述

自民国迄今，一些政治家、思想家及学者分别从自然科学角度和社会历史角度对民国初年灾荒史予以诠释，依时间而言主要集中于20世纪80年代以后，依内容而言又呈现出一种多元化的态势．其间，虽然取得了一定的成就，诸如积累了一些资料、研究内容多样化等，但仍存在着一些不足。     

Early amniocentesis and fetal nuchal translucency in women requesting karyotyping for advanced maternal age

Fetal nuchal translucency was measured at 11–14 weeks' gestation in 97 pregnancies referred for early amniocentesis for advanced maternal age. The nuchal translucency was abnormal in 11 fetuses and the fetal karyotype was abnormal in five of these 11 cases. The karyotype was normal in 86 cases with normal nuchal translucency. The culture failure and miscarriage rates associated with early amniocentesis were 3·3 per cent and 2·2 per cent respectively. Amniotic fluid leakage occurred in 6 per cent of cases. In women requesting fetal karyotyping for advanced maternal age without additional biochemical screening, fetal nuchal translucency should be measured at 11–14 weeks. If the nuchal thickness is ≥ 3 mm, a first-trimester diagnostic procedure is indicated; however, if it is <3 mm, amniocentesis should be delayed until 16 weeks' gestation.     

Ultrasound observation of amnion dysmorphism at 14.5–16 weeks

The presence of chorio-amniotic separation and amnion anomalies was recorded in 9500 patients referred for vaginal ultrasound examination at 14.5–16 weeks' gestation. In all patients with a change in the amnion, a search for fetal anomalies was performed and pregnancy outcome was checked. Amnion dysmorphism was observed in 30 cases. The main findings were a floating membrane which changed its configuration when the uterus was tilted and multiple intrauterine amniotic sheets. In no case was attachment of the fetus to the membranes noted. There was no fetal abnormality and pregnancy outcome was favourable in all patients. In conclusion, ultrasound visualization of amnion dysmorphism in early pregnancy is not associated with an adverse pregnancy outcome.     

建筑施工高处吊篮作业安全防护预警模型研究

为提升高处吊篮作业的安全防护水平,为建筑施工安全防护预警模型研究提供理论支持,针对安全防护不足和缺位对高处吊篮作业的不利影响,建立高处吊篮作业安全防护预警指标体系。通过对作业人员的筛选,作业信息采集及数据化处理,构建基于SVM（支持向量机）的高处吊篮作业安全防护预警模型。最后,通过对历史样本数据仿真模拟验证模型的适用性和可行性。研究结果表明:建筑施工高处吊篮作业安全防护预警模型的仿真模拟结果与实际结果相比较为吻合,从安全防护审批、个体防护用品、安全防护设施、安全防护标识、心理生理防护及作业条件防护6个方面进行分析构建的安全防护预警模型可为高处吊篮作业提供预警支持,并可作为建筑企业安全管理系统的一部分,推广至其他特种作业领域。     

突发性环境污染事故预警系统的探讨

突发性环境污染事故时有发生，因此有必要提出事故预防和管理水平，应建立突发性环境污染事故的预警系统。     

Assessing water quality in a tropical lake using biomarkers in zebrafish embryos: developmental toxicity and stress protein responses

In order to achieve a more substantial appraisal of lake water quality, the assessment must not be based only on chemical measurements and analyses of the water itself, but even more so on the impact of existing conditions on aquatic biota. This is possible with the use of biotests or biomarkers, e.g. investigations of the developmental parameters (96-h embryotoxicity evaluate) or of the induction of heat shock proteins (proteotoxicity evaluate). To evaluate the suitability of these tests for environmental screening, fertilized zebrafish eggs were exposed to water samples collected from five sites of varying levels of stress from Laguna Lake, Philippines. Reconstituted water was used as laboratory control while water samples from a highly polluted freshwater source was used as positive control. Developmental parameters were noted and described within 48 and 96 h of exposure. Dilution experiments of the positive control were also done to further assess and compare toxicity potentials of Laguna Lake waters with those originating from a polluted freshwater. After the 96-h exposure, the levels of stress proteins (hsp 70) were determined in embryos from all exposure groups. Results showed 100% mortality in embryos exposed to undiluted positive control (PC) within only 12 h. Increasing dilution levels, however, resulted in lower mortality and lower abnormality rates. No detectable developmental differences were noted among embryos exposed to either the laboratory control or Laguna Lake waters at the end of 96 h, regardless of the source. Very high survival rates and high hatching success rates were observed in embryos exposed to lake waters as well as laboratory control, and the data did not differ significantly among the groups. Likewise, no significant malformations were noted among all developing embryos throughout the exposure period. However, the levels of heat shock proteins in the two sites located closest to Manila, the Philippine capital (Northern West Bay and Central West Bay), showed a pronounced elevation relative to the control, indicating that these stress proteins protect the embryos from the detrimental effects of pollutants in the water. Based on the 96-h early life stage (ELS) test, the water quality of the lake is good for fishery propagation despite the current levels of pollutants in the water. This finding is in accordance with the Class C status (i.e. suitable for fish growth and propagation) as given to the lake by the local environmental agency. On the other hand, data on proteotoxicity showed that the fish are under stress, presumably deriving from pollutants. This calls for a continuous monitoring and improvement of the lake water. The present study indicates that the two biomarker methods are very easy to use, practical, rapid, and sensitive for assessing water quality in a tropical lake and recommends for their incorporation into the future monitoring program of Laguna Lake.     

Monitoring Long-Term Ecological Changes Through the Ecological Monitoring and Assessment Network: Science-Based and Policy Relevant

Ecological monitoring and its associated research programshave often provided answers to various environmental management issues. In the face of changing environmental conditions, ecological monitoring provides decision-makers with reliable information as they grapple with maintaining a sustainable economy and healthy environment. The EcologicalMonitoring and Assessment Network (EMAN) is a national ecological monitoring network consisting of (1) about 100 casestudy sites across the country characterized by long-term multi-disciplinary environmental work conducted by a multitudeof agencies (142 partners and counting); (2) a variety of lesscomprehensive yet more extensive monitoring sites; (3) a network where core monitoring variables of ecosystem change aremeasured; and (4) geo-referenced environmental observations. Environment Canada is the co-ordinating partner for the network through the EMAN Co-ordinating Office. EMAN's mission is to focus a scientifically-sound, policy-relevant ecosystem monitoring and research network based on (a) stabilizing a network of case-study sites operated by a varietyof partners, and (b) developing a number of cooperative dispersedmonitoring initiatives in order to deliver unique and needed goods and services. These goods and services include: (1) an efficient and cost-effective early warning system which detects,describes and reports on changes in Canadian ecosystems at a national or ecozone scale; and (2) cross-disciplinary and cross-jurisdictional assessments of ecosystem status, trends and processes. The early warning system and assessments of ecosystem status, trends and processes provide Environment Canada and partner organizations with timely information thatfacilitates increasingly adaptive policies and priority setting. Canadians are also informed of changes and trends occurring in Canadian ecosystems and, as a result, are betterable to make decisions related to conservation and sustainability.