Direct fetal chromosome studies from chorionic villi

An easy and reproducible technique for direct fetal chromosome analysis after chorionic biopsy is described. Very high colchicine concentration and rehydratation of the fixed villi are the two original points of this method.     

Proactive industrial strategies for the Clean Air Act Amendments of 1990

The Clean Air Act (CAA) Amendments of 1990 was signed into law by President Bush on November 15, 1990. These amendments potentially will have a major impact on virtually every industrial and many commercial facilities throughout the country. The regulations developed to implement this legislation will encompass new approaches to nonattainment, air toxics, accidental releases, acid rain, permits and enforcement. Because of the impact of this legislation the regulations will be implemented over a ten-year period. This paper is an overview of the amendments and recommended proactive strategies for industry.     

Hunted hunters? Effect of group size on predation risk and growth in the Australian subsocial crab spider Diaea ergandros

A reduced predation risk is considered to be a major adaptive advantage of sociality. While most studies are concerned with non-predatory prey species, group-living predators are likely to face similar threats from higher-order predators. We studied the relationship between group size and predation risk in the subsocial crab spider Diaea ergandros by testing predictions from theoretical models including attack abatement as well as the formation of protective retreats. In a field survey, we found predatory clubionid spiders in 35 % of the D. ergandros nests and as predicted, nest size did not correlate with predator presence. In a subsequent laboratory experiment, we observed survival probability, nest construction activity and feeding behaviour including weight development between groups of different sizes as well as in the absence or presence of a predator. Large groups had an advantage in terms of survival and growth compared to smaller groups or single individuals. They also built significantly larger nests than smaller groups, supporting the idea of protective retreat formation being an adaptive benefit to group living. Even though clubionids did attack D. ergandros, they did not significantly affect overall mortality of D. ergandros. The feeding experiment showed that spiders fed on a larger proportion of flies in the presence of a predator. However, these groups gained significantly less weight compared to the control groups, indicating that the potential predators not only act as predators but also as food competitors, constituting a twofold cost for D. ergandros.     

Proactive Industrial Strategies for the Clean Air Act Amendments of 1990

The Clean Air Act (CAA) Amendments of 1990 was signed into law by President Bush on November 15, 1990. These amendments potentially will have a major impact on virtually every industrial and many commercial facilities throughout the country. The regulations developed to implement this legislation will encompass new approaches to nonattainment, air toxics, accidental releases, acid rain, permits and enforcement. Because of the impact of this legislation the regulations will be implemented over a ten-year period. This paper is an overview of the amendments and recommended proactive strategies for industry.     

2003~2020年黄河内蒙古段干流水质演变趋势

为全面了解黄河流域内蒙古段近年来的水环境质量状况及其变化趋势,基于流域内5个监测断面2003~2020年的水质数据,使用主成分分析、聚类分析和长短时记忆模型等多源数据分析方法,结合改进的综合水质标识指数,探究了黄河流域水质的时空变化特征. 结果表明,流域水质状况整体向好并稳定. 时间特征方面,汛期和非汛期水质的主要影响因素存在显著差异,主要与农业灌溉用水和汛期水量增大有关;空间特征方面,可将5个监测断面归为3类,汛期的主要影响因素具有时间特征,而非汛期3类监测断面的水质差异主要由其周边城市的用水结构决定. LSTM模型的预测值变化趋势与真实值拟合效果良好,可对黄河内蒙古段的水质指标进行有效的预测评价,可为黄河干流各河段水质达标控制与管理提供科学依据.