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261.
262.
Richard Louis Edmonds 《环境科学学报(英文版)》1989,1(1):1-14
Environmental problems in China can be divided into two large classes: pollution and destruction of natural environment. Environmental degradation is particularly serious in areas with rapid population growth. In this paper, some of China's major environmental problems, particularly those concerned with land, forests, and continental waters are introduced in order to see how population growth and management have affected these resources over the past few decades. It is also explained how the Chinese plan to cope and eventually solve these problems. 相似文献
263.
D. J. H. Brock 《黑龙江环境通报》1994,14(13):1243-1252
A number of different models of CF carrier screening have now been tested in pilot trials. Apart from opportunistic and cascade testing (which are strictly speaking not true forms of screening), the major programmes have been directed either to young adults in primary care or to pregnant women in antenatal clinics. Only in the latter form of screening has sufficient data been collected to allow conclusions to be reached on the optimum mode of delivery. It seems very probable that when CF carrier screening passes into routine service, it will be the antenatal couple model that is used. 相似文献
264.
A. G. W. Hunter M.D. 《黑龙江环境通报》1987,7(6):433-441
Three hundred and fifty-four women who underwent midtrimester genetic amniocentesis were matched for age, parity, indication, and smoking history, with an equivalent number of women who had declined the procedure, for the purpose of comparing the neonatal respiratory status of their offspring. There was no evidence that the infants exposed to genetic amniocentesis were compromised. 相似文献
265.
Claus Beier Filip Moldan Richard F.Wright 《Ambio-人类环境杂志》2003,32(4):275-282
到2010年<哥德堡议定书>正式实施时,欧洲自20世纪70年代末以来已减少的酸化硫和氮释放量将进一步减少.这里我们论述了通过使用应用于3个大型"清洁雨"实验(即分别在挪威里斯达尔谢伊阿[Risdalsheia],瑞典耶德松[Gardsjon]以及丹麦克洛斯特海泽[Klosterhede]的所谓"屋顶实验")的酸化模型MAGIC讨论恢复酸化陆地生态系统的结果.<哥德堡议定书>的实施将启动通过重建盐基饱和恢复上述3处土壤的进程.恢复率较低,在今后30年中,盐基饱和增加不足5%.气候引发的风暴严重性的加剧将增加海盐输入生态系统的量.这将为土壤提供额外的碱阳离子,并使恢复速度翻一番,同时还将随着沉积的碱阳离子与存储在土壤中的酸性交换导致高海盐输入之后的强酸性脉动.因此,酸化集水区土壤和径流的进一步恢复将取决于酸沉积下降的数量和速率,在近岸系统的情况下,还取决于海盐输入事件的频率和强度. 相似文献
266.
Edmonds Jae Wise Marshall Pitcher Hugh Richels Richard Wigley Tom MacCracken Chris 《Mitigation and Adaptation Strategies for Global Change》1997,1(4):311-339
We report results from the application of an integrated assessment model, MiniCAM 1.0. The model is employed to explore the full range of climate change implications of the successful development of cost effective, advanced, energy technologies. These technologies are shown to have a profound effect on the future magnitude and rate of anthropogenic climate change. We find that the introduction of assumptions developed by a group of ‘bottom-up’ modelers for the LEESS scenarios into a ‘top-down’ model, the Edmonds-Reilly-Barns Model, leads to ‘top down’ emissions trajectories similar to those of the LEESS. The cumulative effect of advanced energy technologies is to reduce annual emissions from fossil fuel use to levels which stabilize atmospheric concentrations below 550 ppmv. While all energy technologies play roles, the introduction of advanced biomass energy production technology is particularly important. The consideration of all greenhouse related anthropogenic emissions, and in particular sulfur dioxide, is found to be important. We find that the consideration of sulfur dioxide emissions coupled to rapid reductions in carbon dioxide emissions leads to higher global mean temperatures prior to 2050 than in the reference case. This result is due to the short-term cooling impact of sulfate aerosols, which dominates the long-term warming impact of CO2 and CH4 in the years prior to 2050. We also show that damage calculations which use only mean global temperature and income may be underestimating damages by up to a factor of five. Disaggregating income reduces this to a factor of two, still a major error. Finally, the role of the discount rate is shown to be extraordinarily important to technology preference. 相似文献
267.
Prenatal diagnosis of trisomy 20 mosaicism was made in two pregnancies by chromosome analysis of cultured amniotic fluid cells. In both cases, the pregnancy continued to term and a healthy male infant was delivered. Regular assessments up to the age of 6-5 years revealed normal physical and intellectual development in both children. 相似文献
268.
In the case-control study of 118 women with autosomal trisomy identified at prenatal diagnosis and their 442 karyotypically normal matched controls, we found that there was no overall association between risk of trisomy and the presence of vaginal bleeding during pregnancy. However, a lengthy duration of bleeding appears to predict increased risk of trisorny. 相似文献
269.
270.
We report in detail two series of chorionic villus cultivation for prenatal chromosomal diagnosis. Chorionic villi were sampled from both first- and second-trimester pregnancies. One hundred cultures were treated with trypsin–EDTA for 2 h and collagenase overnight, (method A) and 100 were treated with trypsin–EDTA for 1 h and collagenase for 2 h (method B). Using short-term enzymatic digestion, the cultivation time was reduced from 14 days to 6 days. Sufficient amounts of metaphases of good quality were present in 93 per cent of primary cultures harvested in situ, whereas enough metaphases of sufficiently good quality were in most cases present only after subcultivation of the cultures using method A. The decrease in cultivation time obtained is probably due to a higher yield of viable cells in monocellular suspension, an increased attachment efficiency, and a more rapid attachment of single cells (within 24 h). 相似文献