Cytogenetic analysis of chorionic villi for prenatal diagnosis: An ACC collaborative study of U.K. data

A prospective 3-year collaborative study was undertaken in 1987 to collect cytogenetic data from diagnostic chorionic villus samples (CVS) in the U.K. in order to determine the predictive value of the chromosome abnormalities encountered. Twenty-seven laboratories contributed a total number of 7595 cases, of which 97·6 per cent were successful. Excluding single cell anomalies, a total of 480 cytogenetic abnormalities were reported, of which 137 were familial structural rearrangements and 343 were de novo problems. Non-mosaic trisomies of chromosomes 13, 18, and 21 (n=157), non-mosaic sex chromosome abnormalities (n=33), and triploidy (n=6) were all confirmed in cells of fetal origin where follow-up information was available. Of the nine remaining non-mosaics including tetraploidy, trisomies of other autosomes, and extra markers, only a trisomy 16 and a case of a supernumerary marker proved genuine. Eighty-eight cases of mosaicism were reported to the study, of which only nine were confirmed as genuine: two cases involving chromosome 13, one trisomy 18, two examples of extra marker chromosomes, three 45,X, and one 47,XXX. There were no reports of false-negative findings. Presumptive maternal cell contamination was encountered in 39 cases, a detected incidence of 0·5 per cent. Four cases of presumptive ‘vanishing twin’ were recorded: in three of these, direct preparations showed a female karyotype, whereas cultures indicated a male (with male fetuses in two cases). The fourth case was of a female fetus with male and female cells in the CVS cultures. Subtle structural chromosome abnormalities were missed in three instances. Accurate prediction of the fetal karyotype was shown to require detailed knowledge of both the nature and the distribution of abnormal cells in the extra-embryonic tissues. In many cases, this could only be made where results from direct preparations and cultured cells were available. A number of conclusions were reached from these and similar data in the literature regarding the reliability of chromosome findings in CVS.     

不同油类对虾蟹类幼体的胁迫效应

了解不同油类对虾蟹类幼体的急性毒性效应。曝油处理采用磁力搅拌器搅拌,一定时间的超声波乳化等操作,模拟溢油在海洋中风浪、涡动、湍流的乳化过程;设置阶梯浓度组,并在多个平行组急性试验的基础上,估算出8种油品对2种虾类和2种蟹类的半致死质量浓度LC50和安全质量浓度MPC,并运用程序编制溢油质量浓度与虾蟹类死亡率相关性的估算模型。经过分析,结果得到：各MPC值参差不齐,差距较大;燃料油普遍比原油的毒性效应大;相同生长阶段,蟹类比虾类抗油毒害性强、中国明对虾Fenneropenaeuschinensis比日本囊对虾Marsupenaeusjaponicus抗油毒害性强、锯缘青蟹Scyllaserrata比三疣梭子蟹Portunustrituberculatu抗油毒害性强。编制的溢油质量浓度与死亡率相关性的评估模型,简易方便直观,为渔业污染事故理赔提供了一定的参考价值,亦为海域的生态经济学评估提供了一种新的研究方法。     

绿色

绿色是生命的原色,是季节变换的符号。但是在现实生活中,她的内涵己在不断变化并得到升华而被广泛地应用。在上世纪70年代,世界单一个环保组织“绿色和平环境保护组织”就是以“绿色”作为头冠,在欧     

AUTOBIOGRAPHICAL MEMORY AND AFFECT UNDER CONDITIONS OF REDUCED ENVIRONMENTAL STIMULATION

Two experiments were conducted to study the effects of 1-hour sessions of flotation REST (restricted environmental stimulation technique) on mood and autobiographical memory. In Study 1, flotation was shown to produce a significant decrease in self-rated anxiety and arousal. Subjects in Study 2, who experienced similar changes in mood and arousal, reported that autobiographical memories retrieved in REST were more pleasant and intense, and had been more frequently recalled in the past, than those recollected in a control environment.     

THE MYTH OF THE INDOOR CITY

Shopping malls have become major features in the urban landscape, yet have received little attention from environmental psychologists. Malls have become more than just a particular type of retail outlet, but places providing a complex array of commercial, community and leisure facilities. They have sought not only to complement urban provision, but to replace it. Malls have become the ‘indoor city'—a new type of place, generating particular repertoires of perceptions, evaluations and behaviours. This paper reviews the predominantly behaviourist approaches that have characterized the analysis of consumer spatial and shopping behaviour and suggests that a transactionalist approach might be more valuable. An empirical study, undertaken in Guildford, U.K., demonstrates that users of the mall do not principally evaluate malls in terms of their retail performance but as social places and spaces satisfying many psychological needs and preferences. They should not be regarded simply as an extension of the high street but rather as different sorts of places. The paper concludes with an extended discussion of the consequences of mall development for the city and urban life, arguing that the indoor city is a myth.     

Variation in prenatal cytogenetic diagnosis: Policies in 13 european countries, 1989–1991

The livebirth prevalence of autosomal chromosomal anomalies is determined by several factors, including maternal age distribution and the impact of prenatal cytogenetic diagnosis (PCD). The impact of PCD varies between countries, as the indications and the uptake vary. In a previous study we described differences in Down syndrome prevalence and the proportion of older mothers. We have now made a survey of the official PCD policies in 25 regions in 13 European countries for the period 1989–1991. In two countries, termination of pregnancy was not available. In the other 11 countries, international agreement existed on five indications: advanced maternal age, a previous child with a chromosomal anomaly, parents who are carriers of a balanced translocation, mothers who are carriers of an X-linked disorder, and malformations at ultrasound. The exact limit for advanced maternal age varied from 35 to 38 years. There was a considerable variation for the indications advanced paternal age, amniocentesis for AFP or DNA, parental anxiety, a previous child with a congenital anomaly, abnormal maternal serum markers, and exposure to radiation/chemotherapy. The PCD uptake for mothers above the maternal age limit varied from 10 to 88 per cent. International harmonization of the indications for PCD is not considered feasible at present, because of the rapid changes in PCD policies even within countries.     

MOVEMENT AND WAYFINDING IN THE KING SAUD UNIVERSITY BUILT ENVIRONMENT: A LOOK AT FRESHMAN ORIENTATION AND ENVIRONMENTAL INFORMATION

One potentially significant, yet hardly investigated, criterion for postoccupancy evaluation is the legibility of a setting—the degree to which a building or group of buildings facilitate the ability of users to find their way around. Legibility is one of the foundation concepts of environmental psychology, yet it has not often been considered enough as a guiding principle in design. The purpose of this paper is to analyse spatial orientation and wayfinding problems encountered by newcomers (freshman students) at the King Saud University (KSU) campus, Saudi Arabia, and to test/relate this to Lynch's elements of the image of cities. The analysis draws on previous research findings, theories, and more general observations, as well as observations made of wayfinding performance and map sketching by 30 high-school students likely to soon enroll at the university. Many specific problems with orientation and the architectural legibility of the buildings are identified and discussed. Emphasis is placed upon physical-setting variables that are likely to affect the ease with which spatial orientation and wayfinding are accomplished. These include the following facets of the KSU built environment: degree of differentiation; degree of visual access; and complexity of spatial layout.Legible buildings within which people can effectively maintain their orientation and find their way, according to this research, are in no way simplistic, dull, or boring; on the contrary, settings must possess distinctive landmarks and regions which, along with understandable path networks, allow users to know where they are and how to make their way to desired destinations. Coherent and legible environments are important in the lives of the people who use them. The movement of people through buildings and the factors that influence whether or not they are able to find their way need to continue to be of significance to both researchers and practitioners.