关于温室气体限排目标的确定（巴西提案）

巴西提案是巴西代表团在联合团气候变化谈判中，提出的一套系统的全新的对中国家有利的理论体系，文章在对巴西提案中的有效排放量、简单气候模式、斐和限额分配方法、消沽发展基金等，进行深入睥评价的基础上，提出应将有效排放量与人均排放量与有机结合， 交圾效人均排放量曙室气体限排目标的指标。     

人工湿地在农业面源污染控制方面的应用

简述了人工湿地的类型及去除氮，磷，有机物的主要机理，人工湿地内植物的作用及其它一些问题，从而说明了人工湿地作为一种造价低，运行简单及管理方便的农业面源污染控制系统在我国尤其是广大城镇和农村地区具有良好的应用前景。     

Prenatal screening for haemoglobin disorders

The technology has been available to detect carriers of haemoglobin disorders since the late 1960s. Prenatal diagnosis has been available since 1978. First trimester diagnosis by chorionic villus sampling and DNA analysis was introduced in 1982, and subsequent simplifications in DNA technology have made screening, counselling and prenatal diagnosis cost-effective at the community level, in countries at all levels of development. Audit of prenatal diagnosis for haemoglobin disorders in countries which have the resources and infrastructure necessary for genetic population screening (such as the UK and other European countries), has shown that the number of prenatal diagnoses actually performed fall far short of expectation. The demonstration that this reflects failures in delivering information, screening and counselling to the populations at risk, rather than rejection of prenatal diagnosis, shows the importance of placing more emphasis on the organisational and social requirements for genetic population screening. In some countries current attitudes towards abortion exclude provision of prenatal diagnosis within the health service, but in many such cases it has been set up in the private sector. It is also being introduced through combined private and charitable efforts in an increasing number of developing countries, including some with extremely limited health resources: such centres are likely to act as nuclei for emergence of genetics services in these communities. A particularly notable recent achievement is the introduction of prenatal diagnosis in Nigeria, where 1–2% of all children born suffer from sickling disorders.     

Human maternal uniparental disomy for chromosome 16 and fetal development

Two severely growth-retarded fetuses found to have maternal uniparental disomy (UPD) for chromosome 16 and trisomy 16 placental mosaicism both had an unfavourable outcome. Antenatally, the first case was complicated by an unexplained raised maternal serum alpha-fetoprotein concentration, preterm premature rupture of the membranes, and growth retardation detectable at 21 weeks' gestation, whilst the other had an unexplained raised maternal serum human chorionic gonadotrophin level, a two-vessel cord on ultrasound, and cessation of growth at 25 weeks. At post-mortem, both babies had an imperforate anus. Fetal maternal UPD may explain the poor outcome that occurs in some cases of confined placental mosaicism for chromosome 16 and is also associated with specific fetal abnormalities.     

Maternal serum CA 125 levels in pregnancies with chromosomally-normal and -abnormal fetuses

We measured the maternal serum cancer antigen 125 (MS-CA 125) levels in 98 nonpregnant women, 765 first- and second-trimester pregnancies with chromosomally-normal fetuses, and 54 chromosomally-abnormal pregnancies. To determine the MS-CA 125 concentration, we used a new automated microparticle enzyme immunoassay with low inter-assay variability. The median MS-CA 125 level decreased from the first to the second trimester of pregnancy and was higher than that in non-pregnant women. We found no difference between normal and Down's syndrome (n = 29) pregnancies ( t-test: t = 0·57, p >0·5). The MS-CA 125 levels in pregnancies with other chromosomal abnormalities showed no difference either, compared with the normals. We conclude that MS-CA 125 is not a useful marker for fetal Down's syndrome, nor for other chromosomal disorders in pregnancy.     

Value of maternal serum unconjugated oestriol measurement in prenatal screening for Down's syndrome

We compared the medical and financial cost-effectiveness of prenatal serum screening for Down's syndrome using maternal age, serum alpha-fetoprotein and human chorionic gonadotrophin with and without the use of unconjugated oestriol. The use of unconjugated oestriol is medically more cost-effective than screening without it at all levels of detection. The actual performance depends on whether gestational age is estimated using ‘dates’ or an ultrasound scan. At a detection rate of 60 per cent, the proportion of unaffected fetal losses per case diagnosed at amniocentesis is about 22 per cent less if gestational age is estimated using dates (time since the first day of the last menstrual period) and about 47 per cent less if it is based on an ultrasound scan examination. At this detection rate, the inclusion of unconjugated oestriol increases costs by about £2k per case diagnosed (£36k instead of £34k) if gestational age is estimated using dates, but it is no more expensive if gestational age is measured from an ultrasound scan examination (indeed, it is more cost-effective at detection rates above 60 per cent). Since there is little change in the financial cost with the inclusion of unconjugated oestriol, for the improved medical performance of screening, it is worthwhile including it in the screening test.     

Abnormal maternal serum chorionic gonadotropin levels in pregnancies with fetal chromosome abnormalities

The alpha subunit of human chorionic gonadotropin (alpha-hCG), human chorionic gonadotropin (hCG) and alpha fetoprotein (AFP) were measured in the serum of 25 women with chromosomally abnormal fetuses between 18 and 25 weeks of gestation and in 74 normal pregnancies. AFP levels less than 0.5 multiples of the median (MoM) or greater than 2.5 MoM were observed in 24 per cent of the abnormal pregnancies and in 6.76 per cent of the normal pregnancies. A low concentration of hCG (< 0.25 MoM) was observed in 8 per cent of abnormals and in 2.7 per cent of normals while an elevated concentration of hCG (>2.5 MoM) was observed in 56 per cent of abnormals and in 1.35 per cent of normals. Elevated hCG-alpha (>2.5 MoM) was observed in 28 per cent of abnormals and in none of the normals. Determination of elevated levels of hCG-alpha or hCG resulted in detection of 68 per cent of pregnancies with chromosomally abnormal fetuses with a false positive rate of 1.35 per cent. Determination of both elevated and depressed gonadotropin levels resulted in detection of 76 per cent of abnormal pregnancies with a false positive rate of 4.05 per cent. Measurement of hCG and hCG-alpha in maternal serum samples can be used as a screening procedure for detecting pregnancies at risk for fetal chromosome abnormalities.     

污染物总量控制目标的确定

污染物总量控制是我国环境管理工作的一大进步。本文从其涵义入手,简要介绍了污染物总量控制指标体系的建立及污染物总量控制目标的确定方法。     

沈阳市2000年环保工作目标及主要任务

在明确沈阳市 2 0 0 0年环保工作的指导思想后 ,着重就确保 2 0 0 0年“一控双达标”和“九五”计划目标的实现所确定的环保工作目标和为实现这一目标应完成的 10项工作任务作了较详尽地阐述。     

矿井通风系统评价方法与标准

分析了几种常见的矿井通风系统评价方法在使用中的利弊 ,指出了《冶金矿山矿井通风系统鉴定指标》中某些指标的缺陷 ,提出了修改意见 ,并根据国内冶金矿山的实际情况 ,制定出了相应的评价标准与方法。