Pork knocking in the land of many waters: Artisanal and small-scale mining (ASM) in Guyana

The growth of artisanal and small-scale mining (ASM) in Guyana has received little attention in the literature, despite its rapid growth and now central importance in this small country's socioeconomic fortunes. Although the activity in Guyana shares commonalities with ASM activity elsewhere in the world, it also displays some unique characteristics. This article builds upon existing debates and current issues surrounding Guyanese ASM. A lack of baseline data and research on the dynamics, underlying forces and various outcomes of the ASM sector has acted as a significant constraint on the regulation and development of the sector in a completely desirable fashion. This has been the result of, but has also been exacerbated by, the ineffective nature of intervention, enforcement and assistance. This paper aims to demonstrate and argue for the need for developing much clearer understandings of and effective interactions with the ASM sector in Guyana. Such all developments are the more pressing given future policies, which may represent potentially sizeable challenges for the continued vibrancy of ASM operations.     

长江口水体中取代芳烃类污染物的生态风险评价

通过对采集于长江口水体15个不同采样点水样中的主要6种取代芳烃类化合物的浓度分析,依据3个基础营养级水平(藻、溞、鱼)的急性毒性效应[L(E)C50],采用欧盟适用于现有化学物质与新化学物质的风险评价技术指南(TGD)中的商值法对长江口水体中的1,3-二氯苯、1,4-二氯苯、1,2-二氯苯、六氯苯、2,4-二硝基甲苯、...     

珠江口滩涂围垦对大型底栖动物群落的影响

为了解海岸滩涂围垦对沿海生态系统的影响,采用大型底栖动物群落来进行影响评价.对珠江口伶仃洋西海岸的6个自然滩涂和5个围垦滩涂的大型底栖动物进行比较研究,采用4种生物指数、聚类分析(CLA)及非度量多维测度排序(NMS)对其进行群落特征分析.结果显示:自然滩涂底栖动物种类数平均7.5种,栖息密度386.63 ind m-2,生物量15.593 6 g m-2,均普遍高于围垦滩涂.滩涂围垦可造成滩涂生境改变,从而导致底栖动物群落结构简单,生物组成单一,群落相似性较低.因此必须科学制定围垦方式并进行围垦后生态保护,在满足用地需求和生境保护之间取得平衡.图5表3参24     

市场经济中的安全工程专业

基于市场经济背景和煤矿企业改革现状，阐明了矿山通风与安全工程专业改革的迫切性和发展的方向，探讨了改革方案。     

就森林资源谈林副产品加工专业的发展前景

本文通过对国内外森林资源利用概况及我校林副产品加工专业的现状分析,阐述了该专业的发展前景。     

On the Issue of Functional Form Choice in Hedonic Price Functions: Further Evidence

/ Historically, researchers applying the hedonic technique devoted little effort to testing alternative functional forms. This study used Box-Cox transformations on a hedonic model examining property value effects of a closed landfill to help select among alternative functional forms. Although this particular application found that a log-log functional form was appropriate, it appears that functional form may vary by problem and case study area selected. Benefit estimates generated using the hedonic technique may be substantial over- or underestimates if the incorrect functional form is chosen. Proximity to the landfill had no significant effect on property values.KEY WORDS: Hedonics; Functional form; Box-Cox; Landfills     

Ecosystem Manipulation Experimentation as a Means of Testing a Biogeochemical Model

2 concentration, and global or regional temperature change. Such model projections are frequently used as the basis or justification for public policy decisions and legislation. A substantial need has therefore arisen to test and substantiate the veracity of mathematical model projections. Unfortunately, environmental models can never be truly validated because natural systems are never closed and model solutions are always nonunique. Partial model confirmation is possible, however, and entails demonstration of agreement between prediction and observation. Experimental ecosystem manipulation provides one of the best, and in many cases only, available basis for model confirmation. The use and potential misuse of data from experimental ecosystem manipulations for model testing is explored using examples drawn from the application of an acid–base chemistry model, MAGIC. As model projections provide an increasingly important basis for public policy decisions, and as both the scientific questions and the models become increasingly complex, it will become critical to provide data from a suite of well-designed ecosystem manipulation experiments in order to evaluate the quality and uncertainty of those model projections and the models upon which they are based.     

矿井安全评价中的几个问题的初步研究

研究了矿井灾害系统危险评价中的几个关键问题，分析了煤矿灾害系统的结构特点，针对矿井灾害系统这样一个过程性本质模糊的灾害发生环境，提出了危险程度的模糊风险度量理论和基于此理论的定量表示方法，以及对不同灾害事故后果相关性计算方法。还论述了全矿与其各组成部分的危险程度之间的相互关系。