热力学理论在湖泊富营养化研究中的应用

本文在分析了生态系统进化的热力学理论（最大能量、最大功率、最大优势原理）的基础上，综述了能量、功率和优势值在国内外湖泊富营养化研究中的应用，说明生态系统进化的热力学理论为认识和研究复杂的湖泊生态系统提供了整体性的途径，并指出为把热力学理论有效地用于湖泊富营养化的研究而应加强的科研工作。     

丙烯醛与DNA碱基反应机理的AM1研究

 采用AM1方法计算了在水合质子的参与下，丙烯酸与DNA鸟嘌呤碱基发生烷化加成的可能的反应过程，从得到的能量关联图可以看出，除了其中的一个分子内质子迁移过程外，其余的每一反应过程体系的能量均是降低的,计算得到的各关键步骤的反应活化能均不大，反应易于进行,根据计算的自由能可以看出，整个反应能够自发进行，说明丙烯酸可经过2次烷化加成反应与DNA碱基发生交联作用.     

模糊数学在环保基金投资效益分析中的应用

从模糊分析的基本概念出发，采用“主因素决定型：的综合评综合方法，提出了环保基金效益分析模糊隶属度原则，建立了保投资效益分析的模糊数学模型，通过实例分析表明：（１）环保基金投分析应选择污染投资费比，污染物削减费比，污染物处理效益和污染物去除率４个综合指标；（２）应用模型的预测功能，对年度早报的污染物治理项目优劣进行效益分析筛选，排序，为科学合理的编制年度计划提供依据。     

破壁化学注浆防渗理论与工程实践

破壁化学注浆防渗技术的关键是选择化学材料,确定注浆压力,估算浆液扩散半径,布置注浆孔,计算注浆量。本文结合工程实践,得出了注浆参数选择的理论计算公式和工程经验数值;为今后煤矿井壁防渗注浆提供了参考。     

A quantitative estimation of the effect of prenatal diagnosis in dizygotic twin pregnancies in women of advanced maternal age

Genetic counselling in a dizygotic twin pregnancy is complicated by the large number of possible pregnancy outcomes and by the conceivable differences in the parental valuation of these outcomes. We present the probability distributions of the pregnancy outcomes in dizygotic twin pregnancies for women from 35 to 45 years old without prenatal diagnosis and with transabdominal chorionic villus sampling (TA-CVS) or amniocentesis (AC), using data from the literature. TA-CVS always gives a higher probability of a favourable pregnancy outcome (the birth of one or two infants with a normal karyotype) than AC. For a 35-year-old woman, a 0·7 per cent risk of an unfavourable pregnancy outcome without prenatal diagnosis has to be weighed against the 2·1 per cent excess risk of loss of the entire pregnancy after TA-CVS. For a 45-year-old woman, a 10·2 per cent risk of an unfavourable pregnancy outcome without TA-CVS has to be balanced against a 4·4 per cent excess risk of pregnancy loss after TA-CVS. This study provides a quantitative tool for the support of individual parents with respect to the decision to undergo prenatal diagnosis in a dizygotic twin pregnancy.     

Parental decisions regarding termination of pregnancy following prenatal detection of sex chromosome abnormality

In the period of a retrospective study (1979–1984 inclusive) forty cases of sex chromosome aneuploidy were identified at amniocentesis in Oxford, England and in Kuopio, Finland; 25 of these pregnancies were subsequently terminated. A decision to continue was made more often for XYY and XXX karyotypes, by older mothers and older fathers, by couples with more previous children, and by couples living in England. A decision to terminate was made more often for XXY and non-mosaic 45,X karyotypes, by younger mothers and younger fathers, by couples with few previous children, in all cases with abnormal ultrasound findings, when post-amniocentesis counselling was given by an obstetrician, and by couples living in Finland. Previous miscarriages, or terminations of pregnancy, previous problems with infertility, marital status, or the type of counselling given before amniocentesis, appeared not to influence a couples' decision. Religious and ethical ideas were not studied systematically at the time and cannot be reported on.     

Guidelines for Systematic Review in Conservation and Environmental Management

Abstract:  An increasing number of applied disciplines are utilizing evidence-based frameworks to review and disseminate the effectiveness of management and policy interventions. The rationale is that increased accessibility of the best available evidence will provide a more efficient and less biased platform for decision making. We argue that there are significant benefits for conservation in using such a framework, but the scientific community needs to undertake and disseminate more systematic reviews before the full benefit can be realized. We devised a set of guidelines for undertaking formalized systematic review, based on a health services model. The guideline stages include planning and conducting a review, including protocol formation, search strategy, data inclusion, data extraction, and analysis. Review dissemination is addressed in terms of current developments and future plans for a Web-based open-access library. By the use of case studies we highlight critical modifications to guidelines for protocol formulation, data-quality assessment, data extraction, and data synthesis for conservation and environmental management. Ecological data presented significant but soluble challenges for the systematic review process, particularly in terms of the quantity, accessibility, and diverse quality of available data. In the field of conservation and environmental management there needs to be further engagement of scientists and practitioners to develop and take ownership of an evidence-based framework.     

Restoring habitat corridors in fragmented landscapes using optimization and percolation models

Landscape fragmentation and habitat loss are significant threats to the conservation of biological diversity. Creating and restoring corridors between isolated habitat patches can help mitigate or reverse the impacts of fragmentation. It is important that restoration and protection efforts be undertaken in the most efficient and effective way possible because conservation budgets are often severely limited. We address the question of where restoration should take place to efficiently reconnect habitat with a landscape-spanning corridor. Building upon findings in percolation theory, we develop a shortest-path optimization methodology for assessing the minimum amount of restoration needed to establish such corridors. This methodology is applied to large numbers of simulated fragmented landscapes to generate mean and variance statistics for the amount of restoration needed. The results provide new information about the expected level of resources needed to realize different corridor configurations under different degrees of fragmentation and different characterizations of habitat connectivity (“neighbor rules”). These results are expected to be of interest to conservation planners and managers in the allocation of conservation resources to restoration projects.     

On the optimal control of carbon dioxide emissions: an application of FUND

This paper presents the Climate Framework for Uncertainty, Negotiation and Distribution (FUND), an integrated assessment model of climate change, and discusses selected results. FUND is a nine‐region model of the world economy and its interactions with climate, running in time steps of one year from 1990 to 2200. The model consists of scenarios for economy and population, which are perturbed by climate change and greenhouse gas emission reduction policy. Each region optimizes its net present welfare. Policy variables are energy and carbon efficiency improvement, and sequestering carbon dioxide in forests. It is found that reducing conventional air pollution is a major reason to abate carbon dioxide emissions. Climate change is an additional reason to abate emissions. Reducing and changing energy use is preferred as an option over sequestering carbon. Under non‐cooperation, free riding as well as assurance behaviour is observed in the model. The scope for joint implementation is limited. Under cooperation, optimal emission abatement is (slightly) higher than under non‐cooperation, but the global coalition is not self‐enforcing while side payments are insufficient. Optimal emission control under non‐cooperation is less than currently discussed under the Framework Convention on Climate Change, but higher than observed in practice. This revised version was published online in July 2006 with corrections to the Cover Date.     

城市区域环境噪声监测优化布点探讨

应用数理统计中抽样理论，对瑞安市环境噪声监测点进行了优化组合，方法简单易行，兼顾了功能区特征，减少了测点数，并能达到要求的准确性。