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111.
112.
It has been previously reported that a low or absent maternal serum unconjugated estriol (uE3) level is associated with placental steroid sulfatase (STS) deficiency. Here we report a correlation between patients who present with a very low or absent maternal serum uE3 and a deletion of the STS gene as assessed by fluorescence in situ hybridization (FISH). We studied nine prenatal cases that presented to the clinical laboratory with an abnormal triple screen, specifically low or absent maternal serum uE3 and a 46,XY karyotype. FISH analysis showed complete deletion of a probe containing the STS gene in six cases and one case had a partial deletion (reduced but not absent signal). The remaining two cases were not deleted for the STS probe. All mothers tested whose fetus showed a deletion were shown to be STS deletion carriers using FISH. Biochemical analysis was performed on 7/9 prenatal specimens. All fetuses deleted for the STS probe were also found to be deficient for STS by biochemical analysis of cultured amniotic fluid (5/5). Of the two fetuses not deleted for the STS probe, one was deficient for STS activity, while the other had a normal result. The abnormal result of enzyme deficiency by biochemical analysis in a non-deletion case likely represents a mutation in the STS gene, not detectable by this FISH assay. Postnatal FISH confirmation of the STS deletion was performed in 1/7 cases. Clinical follow-up was available for 4/9 cases following birth. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
113.
While new environmental policies and procedures often are developed incrementally, they can also result from crises or other significant events. In situations where policies and procedures are introduced in response to a crisis, questions about the strengths and weaknesses of existing mechanisms, and the extent to which they can be used to address concerns, may be ignored. This paper explores the complexities of introducing new policies and processes where planning systems and procedures already exist. Drinking water source protection policies that are being developed in response to the tragic events in Walkerton, Ontario, Canada serve as the context for the inquiry. Three case study watersheds were selected to reflect the diversity of municipal jurisdictions and water supply systems in Ontario. A content analysis was undertaken on regulatory and non-regulatory policy documents to determine the extent to which they addressed elements of the multi-barrier approach for drinking water safety. Findings from the research reveal considerable evidence of the multi-barrier approach in the policy and guiding documents analyzed. Policy development in response to a crisis can advance progress on the issue of drinking water safety and coincide with emerging governance strategies. Policy effectiveness may be enhanced by considering existing policies as well as contextual and jurisdictional differences.  相似文献   
114.
Earthworm assisted bioremediation of organic contaminants   总被引:8,自引:1,他引:7  
Due to their biological, chemical and physical actions, earthworms can be directly employed within bioremediation strategies to promote biodegradation of organic contaminants. Earthworms have been shown to aerate and bioturbate soils and improve their nutritional status and fertility, which are variables known to limit bioremediation. Earthworms have also been shown to retard the binding of organic contaminants to soils, release previously soil-bound contaminants for subsequent degradation, and promote and disperse organic contaminant degrading microorganisms. This review discusses these earthworm actions upon the soil environment and how they might influence the fate and behaviour of soil associated organic contaminants, subsequently improving bioremediation potential. The latter part of this review considers organic compounds in the following order: agrochemicals, petroleum and crude oil hydrocarbons, PAHs and PCBs.  相似文献   
115.
The movement of copper, chromium and arsenic originating from samples of the wood preservative Tanalith® through mildly acidic, sandy loam soil was investigated. Small, undisturbed soil cores (of dimensions 15 × 15 × 15 cm) were removed from the topsoil of a paddock adjacent to the Glenelg River in the Western District of Victoria, Australia. The paddock soils were thin (<30cm) greyish brown, mildly acidic, sandy loams with a moderate organic carbon content (2–5%) overlying a limestone cap. Tanalith® was applied to the surface of the cores which were then irrigated with deionised water at approximately 30 mm day‐1. Copper concentrations in all leachate remained at background levels throughout the experiment, and this element was found to be immobilised in the top 4 cm of the soil. Up to 29% of the applied dose of chromium was detected in the leachate, with breakthrough occurring within 20 days of Tanalith® application. Up to 13% ofthe applied dose ofarsenic was detected in the leachate, although in this case breakthrough was not observed until 25 days after Tanalith® application and leachate concentrations were still rising when the experiment came to a close. Significant concentrations of arsenic and chromium were found in the top 6 cm of the soil profile.  相似文献   
116.
A fashionable field of enquiry – the relationship between expressed attitudes and actual behaviour in the context of sustainable development – is complex (Staats et al. 2004 Staats, H, Harland, P and Wilke, H. 2004. Effecting durable change: a team approach to improve environmental behaviour in the household. Environ Behav., 36(3): 341367. [Crossref], [Web of Science ®] [Google Scholar]) and difficult to apply in a policy-relevant manner (Aall and Norland 2005 Aall, C and Norland, I. 2005. The use of the ecological footprint in local politics and administration: results and implications from Norway. Local Environ., 10(2): 159172. [Taylor & Francis Online] [Google Scholar]). However, recent research indicates that the use of a household diary can be beneficial in helping to quantify household environmental impact, in educating householders about their impact, and in identifying major ‘behavioural turning points’, where householders may focus efforts to reduce their environmental impact (Hunter et al. 2006 Hunter, C, Carmichael, K and Pangbourne, K. 2006. Household ecological footprinting using a new diary-based data-gathering approach. Local Environ, 11(3): 307327. [Taylor & Francis Online] [Google Scholar]). In other words, the use of a diary by householders is a potentially powerful tool in encouraging and facilitating desired behavioural change. This paper reports on the initial findings of an innovative study that assessed the use of a household diary approach as a means of framing and collecting household environmental data and, critically, as an educational vehicle for bringing about behavioural change. Based on the initial findings, it is clear that there is some potential to develop practical policy measures that empower householders by allowing them to better grasp their environmental impact and, consequently, recoup positive implications in terms of financial savings (e.g. reducing the amount of food thrown out) and health benefits (e.g. more walking/cycling).  相似文献   
117.
Variability in the Southern Ocean is frequently reflected in changes in the abundance of Antarctic krill Euphausia superba and subsequent effects on dependent predators. However, the nature and consequences of changes in krill population dynamics that accompany fluctuations in its abundance are essentially unknown. A conceptual model, developed from quantitative measures of krill length in the diet of predators at South Georgia from 1991 to 1997, allowed predictions to be made about the abundance and population structure of krill in 1998 and the consequences for predators. Consistent with model predictions, in 1998 there was a serial change in krill population structure, low krill biomass and low reproductive performance of predators. The change in the modal size of krill, from 56 mm in December to 42 mm in March, was apparently a result of the transport of krill into the region. This is the first occasion when the future status and structure of the krill population at South Georgia has been successfully predicted. By representing local krill population dynamics, which may also reflect large-scale physical and biological processes, predators have a potential key role as indicators of environmental variation in the Southern Ocean at a range of spatial scales. Received: 6 March 1999 / Accepted: 3 September 1999  相似文献   
118.
Doroth&#;e Ehrich  Niels M. Schmidt  Gilles Gauthier  Ray Alisauskas  Anders Angerbj&#;rn  Karin Clark  Frauke Ecke  Nina E. Eide  Erik Framstad  Jay Frandsen  Alastair Franke  Olivier Gilg  Marie-Andr&#;e Giroux  Heikki Henttonen  Birger H&#;rnfeldt  Rolf A. Ims  Gennadiy D. Kataev  Sergey P. Kharitonov  Siw T. Killengreen  Charles J. Krebs  Richard B. Lanctot  Nicolas Lecomte  Irina E. Menyushina  Douglas W. Morris  Guy Morrisson  Lauri Oksanen  Tarja Oksanen  Johan Olofsson  Ivan G. Pokrovsky  Igor Yu. Popov  Donald Reid  James D. Roth  Sarah T. Saalfeld  Gustaf Samelius  Benoit Sittler  Sergey M. Sleptsov  Paul A. Smith  Aleksandr A. Sokolov  Natalya A. Sokolova  Mikhail Y. Soloviev  Diana V. Solovyeva 《Ambio》2020,49(3):786-800
Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective.  相似文献   
119.
Environmentally sustainable development is one of the key challenges faced by societies today. Yet it is not a new challenge; throughout history, societies have faced the need to live within environmental constraints. Some have done so well, and some poorly. One society which did well for tens of thousands of years is that of Aboriginal Australia. This paper explores some lessons from Aboriginal Australia which have resonance in the modern world and shows that countries which have learned those lessons are in fact more sustainable than those which have not. It thus suggests that there is much that the pantheon of human experience can teach the modern world as it endeavours to create a sustainable future.  相似文献   
120.
Mercury has various uses in nuclear fuel reprocessing and other nuclear processes, and so it is often present in radioactive and mixed (radioactive and hazardous) wastes. Compliance with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards can require off-gas mercury removal efficiencies up to 99.999% for thermally treating some mixed waste streams. Test programs have demonstrated this level of off-gas mercury control using fixed beds of granular sulfur-impregnated activated carbon. Other results of these tests include (1) the depth of the mercury control mass transfer zone was less than 15-30 cm for the operating conditions of these tests; (2) MERSORB carbon can sorb mercury up to 19 wt % of the carbon mass; and (3) the spent carbon retained almost all (98.3-99.99%) of the mercury during Toxicity Characteristic Leachability Procedure (TCLP) tests, but when even a small fraction of the total mercury dissolves, the spent carbon can fail the TCLP test when the spent carbon contains high mercury concentrations.  相似文献   
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