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61.
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63.
Dr. J. F. Bruch P. Metezeau N. Garcia-Fonknechten Y. Richard V. Tricottet B.-L. Hsi A. Kitzis C. Julien E. Papiernik 《黑龙江环境通报》1991,11(10):787-798
Three monoclonal antibodies (MAbs) against trophoblast (GB17, GB21, and GB25) and flow cytometry were used to sort trophoblast-like cells (TLCs) from peripheral blood of pregnant women. Sorted TLCs were processed for electron microscopy and fetal DNA amplification of the Y-specific sequences from mothers carrying male fetuses. At the ultra-structural level, most of the nucleated cells had the morphology of leucocytes, suggesting maternal contaminants, and we did not find the characteristic features of the free inter-villous trophoblast cells. Nevertheless, polymerase chain reaction (PCR) analysis showed an amplification of Y-specific sequences in two out of three samples of sorted TLCs. These results suggest that besides the maternal leucocytes, sufficient trophoblast nucleated fetal cells can be obtained using cell enrichment by sorting. This sensitive method holds promise for non-invasive prenatal diagnosis of fetal sex and if sufficient Y(positive) nuclei are found, for the diagnosis of selected numerical chromosome abnormalities. 相似文献
64.
Henrietta M. Lidiard Joy E. Rae Andrew Parker 《Environmental geochemistry and health》1993,15(2-3):93-104
A number of Mn-oxide minerals in soils from a farm in North Devon have been tentatively identified using a combination of
advanced analytical techniques: scanning electron microscopy (SEM), scanning electron microprobe (SEMP), X-ray diffraction
(XRD) and bulk chemical analysis by wet digestion followed by inductively-coupled plasma spectrometry (ICP). The minerals
lithiophorite and hollandite are thought to occur throughout the study area although there is considerable geographical variation
in the proportions of minerals present. Bimessite, vernadite, romanechite, todorokite and cryptomelane may also be present,
although in smaller amounts.
The use of SEMP, together with a simple sorption experiment, has allowed a study of the extent of uptake of Co and Cu by different
Mn-oxide minerals. Lithiophorite appears to take up Co and Cu more effectively than hollandite within a pH range of 4–6. 相似文献
65.
Evolution of environmental impact assessment as applied to watershed modification projects in Canada
Herman J. Dirschl Nicholas S. Novakowski M. Husain Sadar 《Environmental management》1993,17(4):545-555
This article reviews the application of environmental impact assessment (EIA) procedures and practices to three watershed
modification projects situaled in western Canada. These ventures were justified for accelerating regional economic development,
and cover the period during which public concerns for protecting the environment rapidly made their way into the national
political agenda. An historical account and analysis of the situation, therefore, seems desirable in order to understand the
development of EIA processes, practices, and methodologies since the start of construction of the first project in 1961. This
study concludes that there has been good progress in predicting and evaluating environmental and related social impacts of
watershed modification proposals. However, a number of obstacles need to be overcome before EIA can firmly establish itself
as an effective planning tool. These difficulties include jurisdictional confusions and conflicts, division of authority and
responsibility in designing and implementing appropriate mitigative and monitoring measures, lack of tested EIA methodologies,
and limited availability of qualified human resources. A number of conclusions and suggestions are offered so that future
watershed modification proposals may be planned and implemented in a more environmentally sustainable fashion. These include:
(1) EIA processes must be completed before irrevocable decisions are made. (2) Any major intrusion into a watershed is likely
to impact on some major components of the ecosystem(s). (3) Mitigation costs must form part of the benefit-cost analysis of
any project proposal. (4) Interjurisdictional cooperation is imperative where watersheds cross political boundaries. (5) The
EIA process is a public process, hence public concerns must be dealt with fairly. (6) The role of science in the EIA process
must be at arms length from project proponents and regulators, and allowed to function in the interest of the protection of
the environment and public health and safety.
The views expressed here are the authors’ own and do not necessarily reflect those of FEARO and/or other government agencies
and officials involved in the review of these projects. 相似文献
66.
The occurrence and impact of psychological contract violations were studied among graduate management alumni (N = 128) who were surveyed twice, once at graduation (immediately following recruitment) and then two years later. Psychological contracts, reciprocal obligations in employment developed during and after recruitment, were reported by a majority of respondents (54.8 per cent) as having been violated by their employers. The impact of violations are examined using both quantitative and qualitative data. Occurrence of violations correlated positively with turnover and negatively with trust, satisfaction and intentions to remain. 相似文献
67.
N. L. Ivanova 《Russian Journal of Ecology》2002,33(2):125-129
Environmental conditions in cooling ponds of thermal power plants are favorable for marsh frogs. Their populations inhabiting Verkhne-Tagil and Reftinskoe reservoirs differ in some traits, such as size and age composition, growth rate after metamorphosis, spawning type, fecundity, and characteristics of larval development. Differentiation in body size manifests itself at the early stages of terrestrial life and progresses at later stages. As a consequence, larger individuals may reach maturity and participate in reproduction at an earlier age. 相似文献
68.
Changes in the survival parameters of the red fox were analyzed at different phases of the population cycle. It was found that the survival rate in all age classes, including newborns, drastically increased at the phase of population growth. The relationship between the general mortality rate and population size was determined. A hypothesis concerning the mechanism of these changes in the general mortality rate is suggested. 相似文献
69.
Steinar Sandφy 《Ambio-人类环境杂志》2003,32(3):162-164
20世纪70和80年代,"酸雨"成为一个主要公共政策问题.在加拿大和北欧的斯堪的纳维亚半岛的酸化水体中,生物群落及生境遭到频繁破坏,诸如土著鲑鱼和鳟鱼种群受损乃至灭绝的现象屡见不鲜. 相似文献
70.
Thi Binh Minh Nguyen A.T.M. Nurul Amin 《Environment, Development and Sustainability》2002,4(3):279-297
In recent years flows of foreign direct investment (FDI) to developing countries have rapidly been increasing. It is now an important contributor to the national economy and urban growth in scores of developing countries. Rapid urbanization in these countries is leading to many problems in the cities. Existing urban infrastructure and municipal services have been unable to cope with the increased demand arising from growing population and rapid economic growth. Consequently, the environment in these cities has deteriorated alarmingly. This paper assesses the role of FDI in urban environmental management (UEM) by analyzing the linkages between them for Hanoi City in Vietnam. The paper's analysis and findings are presented under three main themes: one, FDI, employment and income; two, FDI and environmental degradation; and three, potential of utilizing FDI for the provision of urban environmental infrastructure and services (UEI&S) in order to improve the urban environment. Both primary and secondary source data have been used. Policy implications of the research findings are drawn from the perspective of sustainable development. 相似文献