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321.
During the winter period an inverse linear relation is found between the concentration of dissolved nutrients (phosphorus and nitrogen) and salinity in the Dutch coastal zone. This indicates a conservative behavior of these compounds from the river, through the estuary to the sea. During summer this relation is much more scattered because of biological processes. The physical and statistical properties of the relationship between salinity and the concentration of dissolved inorganic phosphorus and nitrogen are used to calculate when, where, and how many samples have to be taken in order to monitor a reduction of a compound accurately. It appeared that at any given salinity in the estuary and in the sea, the winter period is the most suitable season to detect a reduction of a given dissolved compound. The higher the salinity in the estuary, the more samples are required to prove the reduction significantly. A reduction of only 10% cannot even be demonstrated by field measurements during summer at salinities above 25. It is concluded that one cruise from the river to the sea, covering the salinities from 0 to 35 during the winter period, aimed at establishing the relationship between the concentration and salinity by taking samples at a salinity interval of for instance 1%, is sufficient to monitor a wide-ranging reduction of 10%–50% in both the fresh water and marine water. This program must be combined with a sampling at a salinity of 0, directed to determine the riverine temporal variability.  相似文献   
322.
323.
如今做事都喜欢冠以某某名义,打着响亮的旗号以获得公众乃至国际社会的理解与支持。比如,在”反恐”的名义下,美国总统调集大军去灭掉与自己的价值观不符或敢于向其叫板的政权。此外,“民主”和“人权”也是惯用的口号。对工商企业来说,为增加利润和迎合公众的消费心理,越来越多的采用绿色营销策略一时间,“为环境,保健康”成为产品广告中出现频率颇高的字眼,这也是顺应潮流吧。不过,工商企业在产品绿化方面确实做了很多实在的努力。  相似文献   
324.
We present a methodology for testing and applying a regional baseline for carbon (C) emissions from land-use change, using a spatial modelling approach (hereafter called the Climafor approach). The methodology is based on an analysis of causal factors of previous land-use change (Castillo et al. 2005). Carbon risk matrices constructed from the spatial correlation analysis between observed deforestation and driving factors (Castillo et al. 2005), are used to estimate future carbonemissions within acceptable limits for a forest conservation project. The performance of two risk matrices were tested by estimating carbon emissions between 1975 and 1996 from randomly selected sample plots of sizes varying from 1,600 to 10,000 ha and comparing the results of the observed emissions from these sample plots with the model estimations. Expected emissions from continued land-use change was estimated for the community applying the risk matrices to the current land cover. The methodology provides an objective means of constructing baseline scenarios including confidence intervals, using the sum of variances of the various data sources, such as measured carbon densities, classification errors, errors in the risk matrices, and differences between the model prediction and observed emissions of sample plots due to sample size. The procedures applied in this study also give an indication of the impact of the variance in the various data sources on the size of the confidence intervals, which allows project developers to decide what data sources are essential to improve his baseline. The modelling approach to estimate the deforestation pattern is based on readily available cartographic and census data, whereas data on carbon densities are required to assess the potential for forest conservation projects to offset carbon emissions.  相似文献   
325.
In order to develop a sound biotechnique for monitoring water quality that builds on the previous experiments carried out in our laboratory, a specific D. magna clone C1242 was used to study the effects of pollutants on phototactic behavior, in all experiments, the animals showed a stable and repeatable phototactic index approximated 0.2 in the presence and 0.4 in the absence of fish kairomenes, which decreased significantly in response to pollutants. There existed no pollutant x fish kairomone interaction, indicating the changes in phototactic behavior of animals imposed by pollutants were independent of the presence of fish kairomones. The detection limits for changes in phototactic behavior of D. magna clone C1 242 are 0.04 mg/L for copper, 0.02 mg/L for cadmium, and 0.80 mg/L for PCP, respectively, quite lowerthan LC50(48 h). The changes in phototactic behavior in presence to pollutants occurred quickly(3 h) compared to the period over whole acute toxicity tests. Therefore, D. magna clone C1 242 could be potentially used to monitor water quality. Moreover, the phototactic behavior did not decrease further in the pollutant mixtures employed in our experiments compared to individual pollutants, except in the Cd-PCP Lre.atme~t.This fact suggests that the formation of water quality criteria must be based upon pollutant mixture tests.Keywords: Daphnia; phototactic behavior; copper; cadmium; pentachlorophenol; fish kairomenes  相似文献   
326.
大直径薄壁钢筒变薄旋压成形工艺研究   总被引:2,自引:0,他引:2  
论述大径比高精钢筒变薄旋压成形试验过程 ,通过确定合理工艺过程 ,选择最佳工艺参数 ,从而旋出了合格筒体。结果表明 ,D40 6A钢退火状态变薄旋压性能良好 ,旋压塑性变形稳定 ;有效控制扩径量和壁厚差是变薄旋压成形和获取高精钢筒的关键  相似文献   
327.
四种南京地产栽培野菜蛋白质营养价值的评价研究   总被引:13,自引:0,他引:13  
4种传统野菜已在南京地区规模栽培利用。采用模糊识别法和氨基酸比值系数法,分别以鸡蛋蛋白质为标准蛋白 ,以WHO/FAO氨基酸参考模式为评价标准 ,对这4种野菜蛋白质营养价值进行了评价 ,并与6种常见蔬菜蛋白进行对照比较。结果表明 ,4种野菜蛋白质含量为2.3 %~5.0 % ,蛋白质中氨基酸种类齐全 ,其含量为77.73 %~89.36 % ,必需氨基酸占总氨基酸量的36.72 %~42.04 % ,第一限制性氨基酸为含硫氨基酸 (Met +Cys)。其蛋白质营养价值分别优于同科的一些常见蔬菜。  相似文献   
328.
We present two prenatal cases of trisomy 9 mosaicism, both of which presented intrauterine growth retardation (IUGR) and other abnormal ultrasound findings. In case A, mosaicism was found in amniotic fluid cell cultures, of which 65 per cent were trisomic cells, on average. In case B, trisomic cells were present in amniotic fluid cell cultures (12 per cent) but none were found in fetal cord blood. After autopsy, cytogenetic findings were confirmed in different tissue cultures. It is concluded that echographic indicators are a very useful tool for a correct prenatal diagnostic interpretation of trisomy 9. Suspected trisomy 9 mosaicism always requires further investigation and fetal cord blood cytogenetic analysis may not be considered as providing an accurate diagnosis of fetal trisomy 9.  相似文献   
329.
针对船舶油污事故损害赔偿评估非线性系统的复杂性,分析了人工神经网络技术在该领域应用的可能性,并以20个国际油污基金公约所承认著名赔偿案例为例建立船舶油污事故的神经网络评估模型,该模型对中国船舶油污事故损害赔偿评估具有一定的参考实用价值,为中国船舶油污事故损害赔偿评估提供了一种新颖而方便的计算方法。  相似文献   
330.
加大标准化建设步伐,促进自治区环境监测工作上台阶、上水平。  相似文献   
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