Ecological consequences of dredged material disposal in the marine environment: a holistic assessment of activities around the England and Wales coastline

This study provides a holistic perspective on the ecological effects of dredged material disposal, both intertidally and subtidally. A number of numerical techniques (univariate, distributional, multivariate and meta-analysis) were used to assess impacts at 18 different disposal sites. The analyses revealed that ecological effects associated with dredged material disposal were dependent on the numerical techniques used, and that impacts were disposal-site specific. Disposal-site communities were generally faunistically impoverished to varying degrees, and impacts following intertidal placement were comparable to those of subtidal placement. We conclude that any assessment of the consequences of dredged material disposal to the coastal environment must take account of site-specific variation in prevailing hydrographic regimes and in ecological status, along with information on the disposal activity itself (mode, timing, quantity, frequency and type of material). As would be expected, variability in the latter presents a significant challenge in attempts to generalise about environmental and ecological impacts.     

用摄影测量的光束平差法处理经纬仪观测值及其在工业测量中的应用

本文研究了用摄影测量光束平差法处理经纬仪观测值以解决工业应用中控制网精确测量的。为了证明光束法等效于传统的三维网解法，需要将角度观测值转换成虚拟的像片坐标并进行相应的误差传播，文中为此提出了一种投影的数学模型。此外，还研究了在光束平差法中使用未置平经纬仪的观测值。研究中对两个网进行了试验：一个是工业测量中的控制网，另一个是实验室试验控制网。利用第一个网对光束平差法和传统的三维网法进行比较，结果是：     

Effect of iron type on kinetics and carbon isotopic enrichment of chlorinated ethylenes during abiotic reduction on Fe(0)

Four samples of two commercially available iron brands used as substrate for iron permeable reactive barriers (PRBs) were tested for suitability for remediation of perchloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (cDCE) and vinyl chloride (VC). Kinetic studies indicate that rates of reaction are enhanced for cDCE and VC on Connelly iron (2.8 x 10(-4) to 6.9 x 10(-4) L/m2/hr and 2.0 x 10(-4) to 9.0 x 10(-4) L/m2/hr, for cDCE and VC, respectively) vs. Peerless iron (3.1 x 10(-5) to 4.6 x 10(-5) L/m2/hr and 2.4 x 10(-5) to 4.1 x 10(-5) L/m2/hr, for cDCE and VC, respectively). Carbon isotopic analyses of the residual chlorinated ethylene (CE) during degradation indicate significant fractionation occurs during reductive dechlorination, with, for example, up to 70% enrichment in carbon isotopic values observed when VC is more than 99% degraded. Comparison of fractionation factors (epsilon) indicates significant differences in carbon isotopic fractionation for different iron types and for different CEs. For the lower CEs (cDCE and VC) in particular, both slower reaction rates and larger fractionation are observed for degradation on Peerless vs. Connelly iron. This is the first study to establish a correlation between the rate of abiotic degradation on Fe(0) and the extent of isotopic fractionation, and the first to confirm consistent differences in these two parameters as a function of iron type. The possibility that these differences in kinetics and carbon isotopic fractionation for cDCE and VC are related to differences in branching ratios between competing hydrogenolysis and beta-elimination reactions during reductive dechlorination on the iron surfaces is discussed.     

层控矿床有机地球化学初步研究

地史上由生物死亡后变成的各种有机物质会遭到各种地质作用的改造,尤其是热液活动、岩浆侵入、放射性元素蜕变以及构造变动等地质因素所引起的热能,会使矿床中(主岩中)的有机物出现成熟异常现象。通过对某些层控矿床中有机物质的研究,可以解释成矿物质的来源、沉淀富集机理、含矿热液运移路线和主岩的沉积环境,并且可以指示矿体的大致分布范围,指导找矿勘探。     

世界上最深的钻井

苏联“‘越深’钻探计划科学委员会”主席、新近被任命为地质部部长的Y·A哥兹洛伏斯基(Kozlovsky)教授首次披露了世界上最深钻孔的有关消息.第一口超深钻井位于苏联科技半岛以北靠近挪威边境的地区.钻采开始于1971年,计划钻深15000米,1982年已钻进11500米.第二口超深钻井位于第一口钻井以南的阿塞拜疆,自1977年开钻以来,已完成进尺8000米,计划钻深15000米.从哥兹洛伏斯基公布的首批详细资料中人们将会注意到下述事实:就象在地表浅处一样.混合岩岩基内的裂隙带和破碎带中存在着含矿溶液和天然气的循环流动,而尤其存在着硫化物的矿化富集.     

法国的学术交流

法国的学术交流,可以说是频繁而不铺张,热烈而又实惠.法国国内是这样.与其他国的国际间交往亦是这样.法国每年经常召开各种形式的国际学术交流会,或是由一个或几个大学联合发起.或是由某个科学协会发起,邀请法国附近的德国、意大利、西班牙、葡萄牙、比利时、英国、荷兰、摩洛哥、丹麦、奥地利、瑞典、瑞士、南斯拉夫等国的科技界同行参加.各国代表大都带上一两名助手,或乘飞机.或乘火车,或自己驱车前往.西欧各国之间简单的过境手续.极为方便的电报电话,以及四通八达的公路网.给这种国际间学术活动提供了很大的方便.这样的国际会议.没有迎送场面.没有宴会招待.也没有游山玩水的安排,就是连会议期间的后勤服务人员也很少.