Fate of ingested pyrrolizidine alkaloid N-oxide in the grasshopper Melanoplus sanguinipes

This work was supported by grants of the Deutsche Forschungsgemeinschaft and by the Fonds der Chemischen Industrie to T.H. and by an NSERC Operating grant to M.B.I. We thank C. Theuring foer technical assistance.     

发展核电是世纪选择

我国是世界第二能源消耗大国，能源消费以煤为主，大量燃煤排放的二氧化硫及烟尘等有害物质是造成我国严重大气污染的主要原因。据预测，到2020-2030年，我国的二氧化碳排放总量将超过美国，居世界首位。给我国在履行《联合国气候发展框架公约》的国际谈判中带来巨大的压力。     

Changes in Age-Related Reproductive Tactics in the Female of the Butterfly, Eurema hecabe

The occurrence of mate solicitation by virgin females was investigated in the butterfly Eurema hecabe. Young (1-day-old) virgin females rarely showed mate solicitation to male model, however, old (at least 6-day-old) virgin females frequently showed such flight. The duration of solicitation was significantly longer in older females than in younger ones. The age-related behavioral change occurs with female oogenesis (Hiroki and Kato 1996), and such behavior may thus be a result of female adaptation to maximize their fecundity. Received: 6 November 1997 / Accepted in revised form: 29 June 1998     

女性视域下的民族国家话语构建——新世纪中国女性写作的叙事策略

新世纪中国女性写作从私语化身体写作的困境中走出,采取了与男性写作不同的叙述策略,将目光投向历史、社会、国家等领域。通过对女性家族史的重新讲述,采用日常生活叙事手法,以平凡女性命运的沉浮来表现民族国家的发展历史。通过对女性个体日常生活的叙写,以世俗化的方式传达女性构建民族国家的诉求与愿景。     

Cystic fibrosis: selecting the prenatal screening strategy of choice

Cystic fibrosis is a serious disorder. Research into the treatment of affected individuals is in progress, but a cure is not expected in the near future. In this review, we demonstrate that prenatal screening for cystic fibrosis meets the requirements for a worthwhile screening programme. We explain the reasons that have led us to conclude that one approach (‘couple screening’) is the method of choice. The couple-based approach calls for reporting results to the couple as a unit. Only if both parents are found to be carriers is the result designated screen-positive and an amniocentesis or chorionic villus sampling offered. This offers a substantial reduction in the proportion of women with unaffected pregnancies with positive results (the false-positive rate) compared with other methods without reducing the detection of affected pregnancies. It also avoids creating a screen-positive group for which no definitive diagnosis is available. This is a problem with other screening methods. The couple method can achieve a 72% detection rate for a 0.1% false-positive rate. The screening method is simple, non-invasive, reliable, safe and reasonably cost effective. Existing programmes have shown that screening using this method is acceptable to health care professionals and patients. Setting up a national prenatal screening programme for cystic fibrosis is timely and should be implemented using the couple screening method. Copyright © 2003 John Wiley & Sons, Ltd.     

小边距冲孔模的凹模设计

在五金、家电、办公用品等行业中,常存在一些零件需要先弯曲成形,再进行冲孔。由于结构设计要求,有些孔到弯曲边的距离尺寸较小,尺寸精度要求较高,因此在这类模具设计中,凹模的强度问题较为突出。从结构设计和工艺设计两方面给出了设计这种模具的一些心得体会。     

深度处理:饮用水处理工艺的选择

2007年7月1日新的<生活饮用水卫生标准>正式施行,水质指标由现行水质标准的35项大幅增加到106项,标准对水中多种微量有机污染控制将更加严格,这对供水企业的饮用水处理技术提出了新要求.新标准也引起了公众对饮用水卫生安全问题的广泛关注,饮用水源地的保护、供水企业的技术革新、二次供水系统的完善都会对饮用水的水质有不同程度的影响,而供水企业的技术改造则是保障饮用水卫生安全的关键所在.     

发展循环经济是建设生态文明的必然选择

论述了生态文明是发展循环经济的思想基础和现实要求,指出发展循环经济,建全社会的资源循环利用体系,以最少的能源资源消耗及最小的环境代价,实现经济的可持续发展,是建设生态文明的一条基本途径和必然选择。