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361.
362.
Françoise Muller Sophie Dreux Jean-François Oury Dominique Luton Serge Uzan Michèle Uzan Michel Levardon Marc Dommergues 《黑龙江环境通报》2002,22(11):1001-1004
Women having access to prenatal care late in pregnancy may still wish to benefit from maternal serum screening for Down syndrome. Therefore, we established reference values for α-feto protein (AFP) and free β-human chorionic gonadotrophin (β-hCG), and assessed the diagnostic value of maternal serum marker screening at 18–35 weeks' gestation based upon a series of 4072 sera from unaffected pregnancies and 118 sera from pregnant women with fetuses affected by Down syndrome. Using a 1/250 risk cut-off, a detection rate of 72.9% (95% CI = 71.5–74.3%) was achieved with a false-positive rate of 7.51% (95% CI = 6.71–8.3%). This was not significantly different from the percentages observed in our 14–17 weeks routine screening (50 596 patients): 71.9% (95% CI = 71.5–72.3%) and 6.48% (95% CI = 6.28–6.68%), respectively. Detection and screen-positive rates were, respectively, 51.3% (95% CI = 35.6–67.0%) and 5.95% (95% CI = 5.12–6.68%) in women aunder 35 years of age, and 84.8% (95% CI = 76.9–92.7%) and 24% (95% CI = 20.7–27.3%) in women aged 35 years and over. In conclusion, maternal serum marker screening is feasible at 18 weeks' gestation and later, which may be of interest in selected cases. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
363.
Arun S. Malik Bruce A. Larson Marc Ribaudo 《Journal of the American Water Resources Association》1994,30(3):471-480
ABSTRACT. The limited success of command-and-control policies for reducing nonpoint source (NPS) water pollution mandated under the Federal Water Pollution Control Act (FWPCA) has prompted increased interest in economic incentive policies as an alternative control mechanism. A variety of measures have been proposed ranging from fairly minor modifications of existing policies to substantial revisions including watershed-wide polices that rely on economic incentives. While greater use of economic incentive policies, such as environmental bonds and point/nonpoint source trading is being advocated in the reauthorization of the CWA, the expected effects of individual proposals will be modest. The characteristics of NPS pollution, namely uncertainty and asymmetrical information, underscores that there is no single, ideal policy instrument for controlling the many types of agricultural NPS water pollution. Some of the usual incentive-based policies, such as effluent taxes, are not well suited to the task. Individual incentive policies proposed for the reauthorized CWA, such as pollution trading or deposit/refund systems, are not broadly applicable for heterogeneous pollution situations. Economic incentive policies may be appropriate in some cases, and command-and-control policies will be preferable in others and may in fact complement incentive policies. 相似文献
364.
Michael J. Sebetich Vance C. Kennedy S. Marc Zand Ronald J. Avanzino Gary W. Zellweger 《Journal of the American Water Resources Association》1984,20(1):93-101
ABSTRACT: Injections of NO3 and PO4 were made during September 1975 into Little Lost Man Creek, a small pristine stream in Redwood National Park, California. Chloride, a conservative constituent, was added in a known ratio to the nutrients. Nutrient loss at a downstream point was calculated using concentration of added Cl as a reference. Nitrate nitrogen (NO3-N), added for 4 h, reached 920 μg/1 (above 5 μg/1 background) just below the injection point, but increased only to 405 μg/1 at 310 m downstream. The concentration decrease was attributed to dispersion and to uptake by stream biota. Percent of NO3-N lost decreased with increasing concentration of NO3-N. Phosphate phosphorus (PO4-P) was added a week after the NO3-N for 3 h, causing a concentration increase of 296 μg/1 (above 13 μg/1 background) just below the injection point, of 161 μg/1 at 90 m downstream, and of 98 μg/1 at 310 m. Percent loss of PO4-P at downstream sites increased with increasing PO4-P concentration and also for a short period after peak concentration occurred, but then decreased as PO4-P concentration continued decreasing. Differences in stream response to added NO3-N and PO4-P are attributed to differing rates of reaction with biota and differing degrees of interaction with abiotic stream solids. 相似文献
365.
In 1996, the International Standards Organization (ISO) completed work on an environmental management system (EMS) standard: ISO 14001. The standard involves only five required elements, spans less than five pages, and upon initial review, appears relatively uncomplicated. As well, many of the ISO 14001 requirements may already be present in an organization's existing EMS. Nevertheless, the new standard presents a number of challenges to industry implementation. Whether an organization aims to start from scratch in developing an EMS under ISO 14001 or modify its existing EMS to meet the ISO challenge, implementation requires careful planning and analysis. This article provides a summary of the planning required to implement ISO 14001 at the facility level, including the initial planning effort and the identification of significant environmental impacts, objectives, and targets. The aim will be to eliminate some of the “hype” associated with ISO and provide some practical “how to” guidance for implementing the standard. The discussion begins with an overview of the initial planning effort and then turns to key planning requirements. 相似文献
366.
367.
When control becomes a liability rather than an asset: Comparing home and office days among part‐time teleworkers 下载免费PDF全文
Past research has mainly examined differences between employees working under conventional versus teleworking arrangements or high‐intensity versus low‐intensity teleworking. Yet because many workers combine days worked from the office with days worked from home (part‐time telework), it may be more appropriate to examine within‐individual variation in office versus home days. Accordingly, we compare diary data from 77 employees on three home days and three office days. This setup enables us to contribute to the theoretical debate on the duality of control and accountability. Specifically, by comparing job locations (home versus office), we identify conditions under which job control (worktime control) is more likely to act as an asset or as a liability. Results suggest that ability to concentrate is higher and need for recovery is lower, on home days than on office days. However, on home days, generally high level of worktime control amplifies the association between job demands and need for recovery—whereas this association is reversed when worktime control is generally moderate. No similar differences are observed on office days. Finally, whereas employees experiencing high job demands are more able to concentrate during home days than during office days, worktime control has no differential effect in this respect. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
368.
A spatially explicit and quantitative vulnerability assessment of ecosystem service change in Europe 总被引:5,自引:1,他引:4
Marc J. Metzger Dagmar Schröter Rik Leemans Wolfgang Cramer 《Regional Environmental Change》2008,8(3):91-107
Environmental change alters ecosystem functioning and may put the provision of services to human at risk. This paper presents
a spatially explicit and quantitative assessment of the corresponding vulnerability for Europe, using a new framework designed
to answer multidisciplinary policy relevant questions about the vulnerability of the human-environment system to global change.
Scenarios were constructed for a range of possible changes in socio-economic trends, land uses and climate. These scenarios
were used as inputs in a range of ecosystem models in order to assess the response of ecosystem function as well as the changes
in the services they provide. The framework was used to relate the impacts of changing ecosystem service provision for four
sectors in relation to each other, and to combine them with a simple, but generic index for societal adaptive capacity. By
allowing analysis of different sectors, regions and development pathways, the vulnerability assessment provides a basis for
discussion between stakeholders and policymakers about sustainable management of Europe’s natural resources.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Marc J. MetzgerEmail: |
369.
370.
Marc Naguib Roger Mundry Henrike Hultsch Dietmar Todt 《Behavioral ecology and sociobiology》2002,52(3):216-223
In most species of song birds, males develop song repertoires of several different songs. Among this variety, different songs may be used differently in communication and, thus, may have different functions. Here we studied vocal responses to playback of structurally different songs in male territorial nightingales (Luscinia megarhynchos). Nightingales have enormous vocal repertoires of about 200 song types. Among these songs, one category, whistle songs, sticks out syntactically and acoustically. Here we tested whether or not male nightingales match whistle songs with whistle songs and, if so, whether they also match the pitch of the broadcast whistles. Furthermore, we also tested if nightingales treat whistle songs as a separate category of songs. We conducted interactive playback experiments on nocturnal song in which each male received three playback treatments that differed in the number of whistle songs broadcast. Males responded differently during playbacks by singing significantly more whistle songs when the playback tapes contained many whistle songs than when they contained no whistle songs. Males also frequently matched the pitch of the broadcast whistle songs. In contrast to responses during playback, after the playback terminated males sang more whistle songs when no whistle songs were broadcast than when many whistle songs were broadcast. These findings suggest that whistle songs have a specific signal value and that nightingales treat them as a special song category. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00265-002-0511-1. 相似文献