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351.
352.
Andrew Carlin Caroline Kadji Mieke M. Cannie Serena Resta Xin Kang Jacques C. Jani 《黑龙江环境通报》2020,40(1):125-135
Extremes of fetal growth can increase adverse pregnancy outcomes, and this is equally applicable to single and multiple gestations. Traditionally, these cases have been identified using simple two-dimensional ultrasound which is quite limited by its low precision. Magnetic resonance imaging (MRI) has now been used for many years in obstetrics, mainly as an adjunct to ultrasound for congenital abnormalities and increasingly as part of the post-mortem examination. However, MRI can also be used to accurately assess fetal weight as first demonstrated by Baker et al in 1994, using body volumes rather than standard biometric measurements. This publication was followed by several others, all of which confirmed the superiority of MRI; however, despite this initial promise, the technique has never been successfully integrated into clinical practice. In this review, we provide an overview of the literature, detail the various techniques and formulas currently available, discuss the applicability to specific high-risk groups and present our vision for the future of MRI within clinical obstetrics. 相似文献
353.
Susannah Grice John Stedman Andrew Kent Melanie Hobson John Norris John Abbott Sally Cooke 《Atmospheric environment (Oxford, England : 1994)》2009,43(13):2154-2167
An assessment of recent trends in primary NO2 emissions has been carried out for ten case study locations across the European Union. Estimates of the percentage of NOx from road traffic emitted as primary NO2 (f-NO2) have been derived for 1995, 2000 and 2005 by combining the results of a literature survey of primary NO2 emission factors for different vehicle types and technologies with an emission inventory. Estimates of f-NO2 have also been derived from ambient monitoring data at roadside sites in each case study location using a model.The results of the analysis of trends show that f-NO2 has increased in recent years and that the rate of increase has been greatest since 2000. f-NO2 has increased from 8.6% in 2000 to 12.4% in 2004 as an average across the monitoring sites and from an average of 6.3% in 2000 to 10.6% in 2005 as an average of the emission inventory based calculations for the case study countries. f-NO2 is predicted to increase further to an average of 19.6% in 2010 and 32.0% in 2020 as a result of the further penetration of exhaust after treatment technologies for diesel vehicles in the fleets. This increase is expected to be offset by the large reduction in NOx emissions over this period, resulting in an increase in NO2 emissions from road traffic to 2015, followed by a decline to close to 2004 levels by 2020. Estimates of future ambient NO2 concentrations have also been calculated for the roadside monitoring sites included in the study. At 29 out of 45 of these sites the annual mean NO2 limit value is predicted to be exceeded in 2010. At 22 of these sites, the annual mean concentration is expected to remain above the limit value until 2020 and beyond. 相似文献
354.
Andrew Turner Heather Pollock Murray T. Brown 《Environmental pollution (Barking, Essex : 1987)》2009,157(8-9):2314-2319
The marine macroalga, Ulva lactuca, has been exposed to different concentrations of antifouling paint particles (4–200 mg L?1) in the presence of a fixed quantity of clean estuarine sediment and its photosynthetic response and accumulation of Cu and Zn monitored over a period of 2 days. An immediate (<2 h) toxic effect was elicited under all experimental conditions that was quantitatively related to the concentration of contaminated particles present. Likewise, the rate of leaching of both Cu and Zn was correlated with the concentration of paint particles added. Copper accumulation by the alga increased linearly with aqueous Cu concentration, largely through adsorption to the cell surface, but significant accumulation of Zn was not observed. Thus, in coastal environments where boat maintenance is practiced, discarded antifouling paint particles are an important source of Cu, but not Zn, to U. lactuca. 相似文献
355.
Andrew Dravnieks Walther Schmidtsdorff Morten Meilgaard 《Journal of the Air & Waste Management Association (1995)》2013,63(8):900-905
The reproducibility of odor thresholds determined by forced-choice dynamic triangle olfactometry was studied employing panels of 23- 45 subjects who tested 12 odorants, with four replications for one (1-butanol). Depending on the selection of panelists, their number, and between-session differences in olfactometer variables, the standard deviation of log(threshold) values ranged from 0.12 (same session, different panels of nine) to 0.37 (different sessions, different panels of nine). Among the demographic factors, only age was found significant; those below age of 30 were 1.6-3 times more sensitive than the older group. No systematic sensitivity difference was found between females and males, and nonsmokers and smokers. Suspicion has been raised in the literature that the method used here, ASTM E679, yields biased results. It is shown for panels of 6-45 members that such biases are inconsequential if the range of concentration presented to the panelists is large enough, and the group threshold is well within that range. The Hall-Ellis method of calculation may have a slight advantage for panels of less than eight subjects, but such small panels are not advisable because of their high variability. The method based on the detectability index exhibited more scatter and would need an impracticaliy large number of measurements. 相似文献
356.
The Logical Foundations of Ecological Footprints 总被引:10,自引:0,他引:10
Andrew R.B. Ferguson 《Environment, Development and Sustainability》1999,1(2):149-156
An academic debate about ecological footprints has started at last. It was set in motion by a critical article in Ecological Economics, 29(1), 61–72, by Jeroen C.J.M. van den Bergh and Harmen Verbruggen (henceforth B&V). Being ourselves major users of ecological footprints, we disagree with most of the criticisms that B&V level at the concept. In our experience, there are widespread misunderstandings surrounding the methodology of eco-footprinting, so it seems a good time to set out the logical foundations of eco-footprinting for all those who may have an interest in the subject – surely extending beyond the readers of Ecological Economics. Thus our approach will be a general exposition. However, even those who have not read the article by B&V will doubtless benefit from knowing the sort of criticisms which are made against ecological footprints, so we will also attempt to explain and respond to the criticisms raised by B&V. 相似文献
357.
This paper reports findings from research which sought to examine the characteristics and the behaviour of farms which participate in environmentally friendly farming schemes and initiatives. In contrast with some earlier work in other regions, a wide variety of farmers in the south-west sample had an active level of sympathy or interest in conservation issues, which, despite the broad and at times inaccurate conservation definitions employed by the farmers, led some to spend generously on creative activities, especially woodland planting. However, the importance of geographical influences was paramount, with creative conservation activity almost always undertaken on comparatively poorer land. Poorer land was always most suitable for conservation work, whether that work be done for cosmetic or holistic reasons. 相似文献
358.
Enhanced Sludge Washing (ESW) with caustic has the potential to significantly reduce the amount of sludge-based underground storage tank (UST) high-level radioactive waste at the Hanford Site. The alternative to ESW is a simple sludge wash, a process that does not take advantege of recent dissolution development efforts. During the past several years, studies have been conducted to determine the remediation cost savings derived from the development and deployment of ESW. The tank waste inventory and ESW process performance continues to be revised as waste characterization, and ESW development efforts advance. This study provides a new cost savings estimate based upon the most recent waste inventory and ESW process performance revisions, an estimate of the associated cost savings uncertainty, and an estimate of the rate of return (ROR) on the investment in technology development. The revised remediation cost savings estimate due to ESW of all UST waste at Hanford is $4.8 billion ± $0.7 billion within 95 percent confidence in 1998 dollars. The ROR on investment was estimated to range from 100 percent to 130 percent. A sensitivity analysis indicated that it would be difficult to imagine a remediation scenario for which ESW did not yield a significant remediation cost savings and ROR. 相似文献
359.
Strategies to overcome barriers to the development of sustainable agriculture in Canada: The role of agribusiness 总被引:1,自引:0,他引:1
R. J. Macrae J. Henning S. B. Hill 《Journal of Agricultural and Environmental Ethics》1993,6(1):21-51
Strategies to involve agribusiness in the development of sustainable agricultural systems have been limited by the lack of a comprehensive conceptual framework for identifying the most critical supportive policies, programs and regulations. In this paper, we propose an efficiency/substitution/redesign framework to categorize strategies for modifying agribusiness practices. This framework is then used to identify a diverse range of short, medium, and long-term strategies to be pursued by governments, community groups, academics and agribusiness to support the transition. Strategies discussed include corporate greening, ethical investment, changing the legal status of the corporaton, new business forms and the development of ecological economics. 相似文献
360.
Paul F. Hudak Hugo A. Loaiciga F Andrew Schoolmaster 《Journal of the American Water Resources Association》1993,29(3):383-390
ABSTRACT: Effective monitoring configurations for contaminant detection in groundwater can be designed by analyzing the spatial relationships between candidate sampling sites and aquifer zones susceptible to contamination. Examples of such zones are the domain underlying the contaminant source, zones of probable contaminant migration, and areas occupied by water supply wells. Geographic information systems (GIS) are well-suited to performing key groundwater monitoring network design tasks, such as calculating values for distance variables which quantify the proximity of candidate sites to zones of high pollution susceptibility, and utilizing these variables to quantify relative monitoring value throughout a model domain. Through a case study application, this paper outlines the utility of GIS for detection-based groundwater quality monitoring network design. The results suggest that GIS capabilities for analyzing spatially referenced data can enhance the field-applicability of established methodologies for groundwater monitoring network design. 相似文献