Regional reference sites: a method for assessing stream potentials

Field assessments of impacted streams require a control or at least an unbiased estimate of attainable conditions. Control sites, such as upstream/downstream or wilderness sites, have proven inadequate for assessing attainable ecological conditions where the control streams differ naturally from the impacted streams to a considerable degree or where different disturbances exist than those being studied. Relatively undisturbed reference sites with watersheds in areas having the same land-surface form, soil, potential natural vegetation, and land use as are predominant in large, relatively homogeneous regions are suggested as alternative control sites. These areas are considered typical of the region and therefore the sites also are considered typical of the region because their watersheds exhibit all the terrestrial variables that make that region a region. The logical basis for developing regional reference sites lies in the ability to group watersheds and common stream types into regions by integrating available maps of terrestrial variables that influence streams. Relatively undisturbed reference sites can be selected from typical areas of the regions and from transition zones where one or two of the terrestrial variables are not the predominant one(s) of the region. These reference sites are useful for estimating attainable conditions, for evaluating temporal and spatial changes in ecological integrity, for classifying attainable uses of streams, and for setting biological and environmental criteria.     

Snowblower injuries in Vermont, 1981–1984

The Vermont Department of Health carried out two studies of snowblower injuries in Vermont during the winters of 1982–1983 and 1983–1984. The first was a case-control study in which we assessed risk factors that predisposed operators to injury during snowblower use. We found 20 persons who had been injured by snowblowers and matched 28 controls to these by neighborhood. In this study, owning a snowblower for 1 year or less and having operated a snowblower for 10 days or less in one's lifetime were significantly associated with injury. The second study was population-based. We estimated that approximately 1.5% of Vermont residents owned snowblowers during the winter of 1982–1983 and that, among snowblower owners, injuries occurred at a rate of 1.3/1,000 person-years of ownership (0.1% chance of injury).     

清洁生产是防治工业污染的新战略

介绍了清洁生产的产生背景,指出了我国在贯彻“预防为主”方针中出现的偏向,分析了采取以末端治理与控制的问题与不足。提出了要将清洁生产作为今后防治工业污染中的一项战略目标,在环境管理中实施战略新转变,在环境立法和环境管理制度中真正贯彻“预防为主,防治结合”的方针,通过对企业清洁生产进行环境审计,来推进这一新战略的转变。     

瓦斯爆炸事故的混沌特性及其控制方法初探

我国煤炭地下开采占全部产量的 96 % ,含瓦斯煤层多 ,高瓦斯矿井和突出矿井占矿井总数的4 4 % ,由瓦斯引发的爆炸事故的伤亡人数占全部矿井事故伤亡总数的 6 5 %。针对我国煤矿安全生产的严峻形势 ,笔者在对瓦斯爆炸事故特性进行分析的基础上 ,应用混沌理论对瓦斯爆炸事故的风险以及控制方法进行初步探讨 ,初步建立了瓦斯爆炸事故混沌特性分析模型 ,对预防和控制瓦斯爆炸事故的发生 ,改善矿井安全生产状况具有指导意义。     

双重冗余控制系统故障安全性的研究

为了获得或改善计算机控制系统的安全性 ,从确保系统故障后导向安全的角度出发 ,深入地探讨了双重动态冗余控制系统的故障 安全性 ,从理论上对冗余控制系统故障 安全性进行了分析和推导 ,给出了一般性结论 ,并结合铁路信号计算机控制系统 ,对双重冗余控制系统故障 安全性的设计规则和方法进行了实践与探讨     

气相色谱法测定空气中苯浓度的质量控制

利用控制苯标准气峰高精密度的方法，达到日常用气相色谱法对空气中苯浓度监测质量控制的目的．     

淮河江苏段石油类污染与防治

分析淮河江苏段水体中主要污染物──石油类的分布状况及其变化趋势，并对其成因及防治进行了初步探讨。     

城市污水处理厂治理费用回归方程的建立

合理分析城市污水处理厂费用的组成 ,建立治理费用回归方程 ,是制定污水处理厂汇水区内排污收费标准的基础研究 ,并使城市污水集中控制及正常运转获取支持资金。     

粤东长埔—西岭地区锡矿断裂岩浆控制因素及成矿模式

作者认为莲花山断裂以东长埔—西岭一带的内生锡矿化在成因上主要与燕山早期(J_3)火山侵入杂岩有关,矿质主要来自富锡中酸—酸性同熔型混源岩浆。矿带、矿田、矿床定位严格受线形断裂构造及其结点控制。并以火成岩和断裂格局作为主要地质标志,探讨了区内锡矿成矿模式。     

Assuring the quality of data in the pesticide residue laboratory

Abstract

The importance of quality control procedures to the collection of pesticide residue data is discussed. The equipment requirements of an adequate, safe pesticide residue laboratory are presented. Equipment maintenance, personnel training, and preservation of samples is also reviewed. Appropriate objectives for an intra‐laboratory quality control program are outlined.