环境中的外部性及其内部化

在经济活动中，经济人为了使自己的收益达到最大化，他们会尽可能地使外部成本转嫁给社会，减少自己的内部成本，使社会资源的配置偏离社会的需要，所以，为了使资源的配置达到帕累托最优，就必须使外部成本内部化。内部化外部成本的经济手段有：向经济人征税、界定资源的产权和实行排污权交易制度等措施。     

Comparing the soil quality changes of different land uses determined by two quantitative methods

Soil quality is one of the most important environmental factors in sustaining the global biosphere and developing sustainable agricultural practices.A study was initiated in Wolong Nature Reserve,Sichuan Province,China to elucidate the soil quality changes of natural secondary succession,forest planting and agricultural practices after deforestatin in the humid mountainous region.The soil qualities of six land use types(natural forestland ,grassland,shrub land,secondary index(QI) and soil deterioration index(DI).The QI values of natural forestland ,grassland,shrub land,secondary forestland,cultivated land ,reforested land were 0.8039,0.3277,0.9127,0.6881,0.0285 and 0.3183,respectively.The DI values were 0%,-14%,12%,1%,-26% and -18% respectively.Both indexes suggested that shrub land can restore soil properties.To compare the two methods more directly,a deduced index QI‘based on QI value was developed,.The results showed that DI and AI‘ had a very high linear correlation coefficient(r=0.9775) despite the values were different .Both methods were efficient in evaluating the soil quality levels and DI was a more simple way in soil quality assessment,while QI could show more ecological meanings.     

浅析节日期间化工生产不安全因素及对策

分析了节日期间化工生产潜在的不安全因素,提出了相应的防范对策,旨在促进节日期间化工企业的安全生产工作.     

Propagation functions for monitoring distributional changes

In environmental assessment and monitoring, a primary objective of the investigator is to describe the changes occurring in the environmentally important variables over time. Propagation functions have been proposed to describe the distributional changes occurring in the variable of interest at two different times. McDonald et al. (1992, 1995) proposed an estimator of propagation function under the assumption of normality. We conduct a detailed sensitivity analysis of inference based on the normal model. It turns out that this model is appropriate only for small departures from normality whereas, for moderate to large departures, both estimation and testing of hypothesis break down. Non-parametric estimation of the propagation function based on kernel density estimation is also considered and the robustness of the choice of bandwidth for kernel density estimation is investigated. Bootstrapping is employed to obtain confidence intervals for the propagation function and also to determine the critical regions for testing the significance of distributional changes between two sampling epochs. Also studied briefly is the mathematical form and graphical shape of the propagation function for some parametric bivariate families of distributions. Finally, the proposed estimation techniques are illustrated on a data set of tree ring widths.     

Ranked set sampling: an annotated bibliography

The paper provides an up-to-date annotated bibliography of the literature on ranked set sampling. The bibliography includes all pertinent papers known to the authors, and is intended to cover applications as well as theoretical developments. The annotations are arranged in chronological order and are intended to be sufficiently complete and detailed that a reading from beginning to end would provide a statistically mature reader with a state-of-the-art survey of ranked set sampling, including historical development, current status, and future research directions and applications. A final section of the paper gives a listing of all annotated papers, arranged in alphabetical order by author.This paper was prepared with partial support from the United States Environmental Protection Agency under a Cooperative Agreement Number CR-821531. The contents have not been subject to Agency review and therefore do not necessarily reflect the views or policies of the Agency and no official endorsement should be inferred.     

农村环境质量区划的多元分析

本文提出了适合于农村环境质量区划的分区方法，即首先以主成分分析法分析农村环境质量问题，然后以多种聚类分析法取得一个初始分区系统，最后用判别分析法判别该初始分区系统中各区域单元的类型归属是否正确，对一些类型归属不恰当的作适当调整，最终得到农村环境质量分区系统。文章最后讨论了类型划分问题。     

遥感技术在土壤污染中的应用研究进展

近年来遥感技术不断地拓展着应用的领域和范围，在土壤污染方面得到了广泛的关注和应用。传统土壤污染的研究存在许多弊端，需要耗费大量时间和精力。遥感技术具有建模范围大、实时性短的特点，它的出现使这些繁琐的过程更加简化。特别是近些年来图像处理手段和无人机遥感技术的发展，极大地提高了该技术的应用精度。本文从遥感技术在土壤污染状况的识别、反演、监管和风险评估等方面的应用出发，列举了遥感技术应用过程中常用的反演手段和方法，梳理了监管数据来源和监管对象。通过目前土壤污染与遥感技术结合的发展现状，较为全面地回顾了国内外遥感技术应用于土壤污染的发展历程，总结了遥感技术应用于土壤污染的各个方面的进展，并对该方面的未来发展趋势进行了展望。     

Ultrasound screening for chromosomal anomalies in the first trimester of pregnancy

For the last 6 years, sonographic signs for excessive fluid accumulation in the backs of 10- to 12-week-old fetuses have been looked for prior to transabdominal chorionic biopsy. In 1400 pregnancies, subsequent karyotype analyses revealed 28 cases of Down syndrome. In 15 ( = 54 per cent), a large fluid cushion over most of the back had been documented at the time of biopsy. Only a few chromosomally normal fetuses with the same peculiarity were observed. The cushion was also present in fetuses with trisomies 18 and 13 , and in Turner syndrome. Systematic first-trimester screening for nuchal fluid accumulation seems to be a recommended method for the detection of Down syndrome and other chromosome anomalies in young pregnant women at low risk. It compares favourably with current methods of maternal serum screening performed at 16–18 weeks which require a higher number of invasive procedures.     

Ultrasonographic method for detection of haemoglobin Bart's hydrops fetalis in the second trimester of pregnancy

In nine pregnant women at risk for fetal alpha-thalassaemia, the two affected fetuses were diagnosed by ultrasonography at 18–20 weeks' gestation. In countries with limited resources, ultrasonography provides a cost-effective method of prenatal screening for this condition.     

运用电法勘探方法研究梁宝寺矿的浅层结构

梁宝寺煤矿是一个新建大型现代化矿井,实际揭露的地质及水文地质资料较少,在该矿井实施综合电法勘探-矿井高分辨率电测深和矿井音频电透视,解决了矿井地层、地质构造、水文地质等问题,较好地弥补了实际揭露的地质及水文地质资料较少的问题,为该矿安全生产提供了重要技术支持.