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41.
The paper describes a model, which estimates the risk levels of individual crude oil tankers. The intended use of the model, which is ready for trial implementation at The Norwegian Coastal Administrations new Vard? VTS (Vessel Traffic Service) centre, is to facilitate the comparison of ships and to support a risk based decision on which ships to focus attention on. For a VTS operator, tasked with monitoring hundreds of ships, this is a valuable decision support tool. The model answers the question, "Which ships are likely to produce an oil spill accident, and how much is it likely to spill?".  相似文献   
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Encased embryos of spotted dogfish Scyliorhinus canicula absorbed six radio-isotopes (241Am, 109Cd, 57Co, 134Cs, 54Mn and 65Zn) directly from seawater during short-term experimental exposure, demonstrating the permeability of the egg-case to these contaminants. Embryo to water concentration factors (CFs) ranged from 0.14 for 134Cs to 7.4 for 65Zn. The 65Zn and 57Co CFs increased exponentially with embryo length, whereas the CF for 109Cd declined with length. Among different components of the encased embryo the egg case was the major repository (69-99%) of all six radio-isotopes that were distributed throughout its wall. Egg-case CFs were as high as 10(3) for 57Co and 65Zn, making it the major source of gamma radiation exposure to the embryo and potentially of radio-isotopes for continued absorption by the embryo, following the uptake phase of the experiment. The patterns of uptake by the egg-case approximated linearity for most isotopes and loss rates were isotope-specific; egg-case biokinetics were not greatly affected by the viability of the contained embryo. Within the embryo initial data on radio isotopic distribution show that the skin is their major site of uptake, as previously demonstrated for juveniles.  相似文献   
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马达加斯加是位于莫桑比克带东界的一个研究程度较低的前寒武纪地区,遭受了泛非运动的强烈影响。这个巨大的岛屿是冈瓦纳大陆的关键部分,因而主变质事件的精确测年对于复原这一超大陆是至关重要的。在该岛的东南部,变质作用达到高温低压条件(850℃,5kbar),并受到了中级退变质作用。变质长英质岩石的常规多颗粒U-Pb、单颗粒锆石Pb逐层蒸发法和Sm-Nd同位素年代学研究表明,至少具下元古界年龄的基底是在约5  相似文献   
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Variations in Irgarol 1051 concentrations in the UK's largest marina at Brighton were determined regularly over a period of one year. Aqueous concentrations ranged from <1 to 960 ngl(-1) with highest mean concentrations generally associated with berths for larger vessels and with the main channels. Temporally, highest concentrations were recorded in November through to January and were probably associated with maintenance of vessels in an adjacent boatyard. Elevated levels were also encountered at the beginning of the season, coinciding with the introduction of newly antifouled vessels. Increased concentrations also followed dredging, possibly through re-mobilisation of Irgarol 1051. No correlations were found between dissolved Irgarol 1051 concentrations and pH, temperature or salinity. With the exception of sporadically high concentrations recorded for water samples (probably taken in close proximity to recently antifouled vessels), concentrations rarely exceeded the no observed effect concentration for marine periphyton of 63 ngl(-1). Concentrations of Irgarol 1051 in sediments sampled from the marina ranged from <1 to 77 ngg(-1). Apparent distribution coefficients (K(d)) calculated from sedimentary and aqueous samples (collected simultaneously) are generally within the range of K(d)'s reported from laboratory experiments.  相似文献   
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蒙脱石中水性质的红外光谱分析   总被引:3,自引:0,他引:3  
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Preliminary results of the 1981 Nepal census are analyzed as to urbanization and population movement to the Terai. Noting the substantial shift in the pattern of Nepal's population distribution occurring between 1971-81, and projecting these rates of change for the future, the paper reports a process of transformation wherein Nepal is shifting from a rural hill and mountain society to an urban-subtropical plains (Terai) state. While the flow of migrants to urban areas and the Terai region is well known, the increase in rate of change poses a serious challenge for the Nepalese government. Economic development planning must readjust its goals and assumptions to take into account the massive metamorphosis that is occurring in Nepal. Development efforts aimed at rural hill and mountain areas may need to be reevaluated in light of the changing distribution of population.  相似文献   
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