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481.
The history of amniocentesis utilization in the seventh largest state of the United States is documented from its inception in 1972 through the first half of 1984. Amniocentesis utilization ratios for Ohio residents aged ⩾35 have increased from 0.21 per cent (19/9091) in 1972 to 23.4 per cent (1655/7531) in 1983, representing an average annual growth rate of 43.1 per cent. Of the amniocenteses performed from January 1, 1978–July 1, 1984, 71 per cent were referred for advanced maternal age (⩾35), 15 per cent for maternal anxiety (30–34), 10 per cent for family history or previous child with a genetic defect, and 4 per cent for other reasons. Between 1978-1983 utilization by women 45 years of age was only 20 per cent higher than women 35 even though their risk of giving birth to a Down syndrome child was about one order of magnitude higher. In addition, various factors were tested as to whether they affected utilization of amniocentesis by women ⩾35 during 1978 1983. A strong correlation of +0.89 existed between county population size and utilization ratios. No difference in utilization was found between whites and nonwhites, regardless of county population size. When utilization ratios were compared separately between Protestants, Catholics and other religions in Ohio's most populated county, no statistical differences were found. From 1978–July 1, 1984, the frequency of all cytogenetically abnormal chromosome results observed in Ohio amniocenteses to women ⩾35 was 2.48 per cent (187/7536). Of these, 2.15 per cent (162/7536) had unbalanced karyotypes. Future maximum amniocentesis utilization for women ⩾35 is estimated at 60–70 per cent.  相似文献   
482.
A fatal case of medium-chain acyl-coenzyme A dehydrogenase deficiency is described in a patient who presented with hypoglycaemia and a gross non-ketotic dicarboxylic aciduria. Cultured skin fibroblasts released 14CO2 from [1–14C] octanoic acid at half the normal rate. Prenatal diagnosis was undertaken in a subsequent pregnancy in which cultured amniotic fluid cells revealed a marked reduction in octanoate oxidation indicative of an affected fetus. The pregnancy was terminated and the diagnosis was confirmed by enzyme analysis of skin fibroblasts taken from the fetus. The high residual octanoate oxidation by affected fibroblasts together with the absence of any characteristic abnormality of amniotic fluid organic acids are a potential limitation to the reliability of this type of prenatal diagnosis.  相似文献   
483.
A longitudinal study was carried out on 30 healthy fetuses in order to assess the modifications of fetal blood flow throughout pregnancy. The pulsatility index was evaluated at two-week intervals by means of pulsed Doppler equipment. In the umbilical artery measurements were performed from 20 weeks onwards, whereas in the descending aorta and internal carotid artery analysis started from 26 weeks onwards. A decrease of the pulsatility index in umbilical artery and in the ratio between the pulsatility indexes in umbilical artery and internal carotid artery was found over the second half of pregnancy.  相似文献   
484.
Markedly decreased fetal activity (akinesia/hypokinesia) is usually readily apparent to experienced mothers, and frequently this concern leads to attempts at prenatal diagnosis. We report prenatal diagnosis of two fetuses with congenital contractures, markedly decreased fetal movement, and microcephaly due to severe holoprosencephaly. Such familial recurrence to phenotypically normal parents suggests a newly recognized autosomal recessive or X-linked syndrome that is readily detectable by prenatal ultrasonography.  相似文献   
485.
Sediments affected by fluctuations of hydrocarbon contaminated groundwater were studied at a former military site. Due to remediation, groundwater table fluctuation (GWTF) extends over approximately one meter. Three cores were collected, penetrating through the GWTF zone. Magnetic parameters, sediment properties and hydrocarbon content were measured. We discovered that magnetic concentration parameters increased towards the top of the GWTF zone. Magnetite is responsible for this enhancement; rock magnetic parameters indicate that the newly formed magnetite is in a single domain rather than a superparamagnetic state. The presence of hydrocarbons is apparently essential for magnetite to form, as there is clearly less magnetic enhancement in the core, which is outside of the strongly contaminated area. From our results we conclude that the top of the fluctuation zone has the most intensive geomicrobiological activity probably responsible for magnetite formation. This finding could be relevant for developing methods for simply and quickly detecting oil spills.  相似文献   
486.
Summary The development products of environmental research lag behind in Australia. The conventional technology transfer model may not apply where environmental research, especially in the social sciences, is still seen as marginal to society. Pragmatic planning is needed for strategic security in times of trouble ahead. Cultural alignment with technological advance allows seduction by laboratories, white gladiatorial coats and expensive equipment imparting high credibility. A correctness for research futures disallows more radical pathways by the use of profit watchers, waste watch committees, technocrats and masculinist political views.A new protocol for environmental research and development calls for less complacency, scrutiny of political and military investment in nuclear futures, greater public policy analysis of issues such as pesticides in Australia's cotton industry, more attention to natural systems thresholds, radical review of social mores, more flexible management systems and closer links between strategic land use and environmental planning.She currently works for the New South Wales Department of Water Resources as a Senior Executive Officer. She has published widely on environmental policy analysis and water planning, and is a Director of Australia's National Land and Water Resources Research and Development Corporation.  相似文献   
487.
针对职业安全卫生管理体系(OHSMS)的国际发展趋势,中国劳动保护科学技术学会(CSSTLP)开展了OHSMS的研究与学会OHSMS标准(CSSTLP1000)的制定工作。既与国际惯例接轨,又能结合国内实际情况,是制定我国OHSMS标准的基本原则。在CSSTLP1000标准制定工作中,围绕标准的运行模式、内容等问题,进行了深入的研究思考。在分析国际上现有的OHSMS标准的共同特点及我国现行有效职业安全卫生管理制度的基础上,确立了CSSTLP1000标准运行模式、内容及标准系列  相似文献   
488.
易燃、易爆、有毒重大危险源评价方法与控制措施   总被引:23,自引:9,他引:14  
论述了重大危险源和重大事故隐患的定义;介绍了易燃、易爆、有毒重大危险源评价方法;在辨识评价的基础上,提出了制定重大危险源事故应急计划,加强监控、管理等措施  相似文献   
489.
Worcester Polytechnic Institute's (WPI) unique academic plan enables students to study sustainable development and the environment as part of an international educational experience. As a technological university, WPI requires students to complete an interdisciplinary project on the interaction of science or technology and society. This paper describes the environmental projects completed by WPI students, in Bangkok, Venice and Guayaquil. The lessons from WPI's experience provide a model for environmental education at other institutions. These interdisciplinary projects not only promote environmental awareness among students, but they also provide tangible assistance to regions which are developing strategies for sustainable development.  相似文献   
490.
Summary This paper highlights the environmental problems confronting Botswana, which include growing pressure on water resources resulting from increases in population, urbanization and development, deforestation, overgrazing and rangeland degradation in the face of unfavourable environmental and climatic conditions. The paper also describes the role of the government through its National Conservation Strategy, and how this proffers possible solutions to these probems. Such solutions include, among others improved planning and administrative measures in the interest of both protecting water resources against pollution and the possible introduction of an incentive to encourage the collection of rain water, and government legislation which will lead to improvement in the management of both rangelands and livestock to prevent rangeland degradation, as well as the government intention to update its forestry policy to provide a comprehensive National Forestry Management Plan. The paper also examines the efforts of nongovernmental organizations including the Kalahari Conservation Society, the Forestry Association of Botswana, Thusano Lefatsheng and the Botswana Society. These non-governmental organizations are greatly involved in natural resource conservation and utilization and, in addition, they provide avenues for the discussion of issues relating to the environment and natural resources for public awareness. The paper finally discusses the role of community education, by examining the environmental awareness in terms of the population.This paper was presented at the Global Forum '94 Academic Conference, Manchester, UK.  相似文献   
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