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排序方式: 共有292条查询结果,搜索用时 15 毫秒
191.
Studies of the seasonal distribution of heterotrophic bacteria in Chesapeake Bay (USA) led us to the observation that fungizone was selective for actinomycetes without appreciably altering the total viable aerobic, heterotrophic bacterial counts. A study of the actinomycete populations in the Bay was undertaken, with several media compared for ability to enrich for actinomycetes: basal, casein, Czapek, starch-casein, glycerol-glycine, chitin and oil agar No. 2. Between 40 and 100% of the colonies appearing on chitin and oil No. 2 media were found to be actinomycetes, compared with <2% for the other media employed. It was also found that if sediment samples are frozen, a practice followed when laboratory facilities are not available in the field, a decrease in the total counts and in the actinomycete colony counts occurred. However, on a proportional basis, a slight increase in the percent actinomycetes was noted. A minimum of 21 days incubation time is recommended for recovery of actinomycetes. Also, the absence of NaCl from the actinomycete isolation media and incubation temperatures ≥15°C should give good recoveries of actinomycetes. A seasonal distribution of actinomycetes was noted for Chesapeake Bay, with maximal populations of actinomycetes observed in March and November. Actinomycetes were isolated in the ocean from depths ranging from 7 to 7,790 m. Greater numbers of actinomycetes were isolated using an incubation temperature of 25°C for the estuarine stations and 15°C for the deep-ocean stations. Greater numbers of actinomycetes were associated with polluted environments close to shore.  相似文献   
192.
Lowther  J. A.  Cross  L.  Stapleton  T.  Gustar  N. E.  Walker  D. I.  Sills  M.  Treagus  S.  Pollington  V.  Lees  D. N. 《Food and environmental virology》2019,11(3):247-258
Food and Environmental Virology - Contamination of bivalve shellfish, particularly oysters, with norovirus is recognised as a significant food safety risk. Methods for quantification of norovirus...  相似文献   
193.
The Clinch River is located in northeastern Tennessee (TN) and southwestern Virginia (VA) of the United States, and contains a diverse mussel assemblage of 46 extant species, including 20 species listed as federally endangered. To facilitate quantitative monitoring of the fauna, quadrat data were collected from 2004 to 2009 at 18 sites in the river, including 12 sites in TN and 6 sites in VA. Thirty‐eight mussel species were collected alive in total from quadrat samples taken annually at sites in the TN section of the river. Over the five‐year study period, mussel density averaged 25.5 m?2 at all sites sampled in TN. In contrast, mussel density averaged only 3.1 m?2 at sites sampled in VA. The best historical site in VA was Pendleton Island in Scott County, where mussel density was estimated as high as 25 m?2 in 1979, comparable to current densities recorded in TN. Mussel densities are now <1 m?2, indicating a collapse of the fauna. A severe reduction in mussel abundance has occurred in a 68‐km section of the river from St. Paul, VA, downstream to approximately Clinchport, VA (river kilometers 411.5‐343.3). While the environmental factors responsible for the faunal decline are largely unknown, they must have been severe and sustained to reduce such large populations to their current low levels. Long‐term water and habitat quality monitoring is needed to determine whether environmental degradation is still occurring in the river.  相似文献   
194.
Data needed for informed conservation prioritization are generally greater than the data available, and surrogates are often used. Although the need to anticipate threats is recognized, the effectiveness of surrogates for predicting habitat loss (or vulnerability) to land-use change is seldom tested. Here, we compared properties of two different vulnerability surrogates to validated vulnerability—validated prediction of habitat conversion based on a recent assessment of land-use change. We found that neither surrogate was a particularly effective predictor of vulnerability. Importantly, both surrogates performed poorly in places most imminently threatened with habitat conversion. We also show that the majority of areas protected over the last two decades have low vulnerability to the most active threatening process in this biome (habitat conversion). The contrary patterns of vulnerability and protection suggest that use of validated vulnerability would help to clarify protection needs, which might lead to the improvement of conservation decisions. Our study suggests the integration of validated vulnerability into conservation planning tools may be an important requirement for effective conservation planning in rapidly changing landscapes. We apply our results to discuss the practical considerations and potential value of incorporating validated vulnerability into conservation planning tools both generally and in the context of New Zealand’s indigenous grasslands.  相似文献   
195.
Swine manure slurries were ozonated at a dosage of 1 g/L and tested for their toxicity to the house fly (Musca domestica). The observed toxicity of ozonated swine manure was consistent and independent of origin of the swine manure. A dose (dilution) response curve was performed. A 50% dilution in the ozonated swine manure slurry resulted in 90% reduction in toxicity. Neither the synthetic nor ozonated synthetic swine manure, both of which contained higher concentrations of formaldehyde and three other unidentified carbonyl compounds than the ozonated swine manure, were toxic to the flies. Ozonated swine manure slurry was centrifuged and passed through a 0.45-microm filter. The liquid phase was as toxic as the unfiltered slurry; as such, the toxicant appears to be present in liquid phase. Neither ammonia, hydrogen sulfide, formaldehyde, nor other simple aldehydes appeared to be the toxic agent. The toxic agent appears to be a polar chemical compound and is concentrated in the urine. Several possible compounds have been identified. The toxicity of untreated and ozonated manure slurries from different livestock was compared. Six animal manure slurries (beef and dairy cattle, horse, poultry, sheep, and swine) were ozonated (dosage of 1 g/L) and tested for toxicity to the house fly. Ozonated dairy cattle manure slurry showed 78% mortality after 72 h, whereas ozonated swine manure slurry achieved a 100% mortality rate in 48 h. Neither the unozonated dairy nor swine manure slurries, nor any of the other raw or ozonated manure slurries, were toxic to the flies.  相似文献   
196.
PROBLEM: The rapid growth of teleworking has raised several social and legal issues regarding an employer's responsibility for the safety of an employee's home office. In this paper, researchers discuss the need for safety training for teleworkers and the effectiveness of a home office ergonomics training program. METHOD: Study participants (N = 50) were randomly assigned into a treatment or control group. The treatment group completed the ergonomics training and a pre- and posttest. The control group completed the pre- and posttests without training. RESULTS: The study demonstrated the need for teleworker ergonomics training. More than 85% of participants had not received teleworker training before, and 44% had experienced pain or discomfort while teleworking. Participants who completed the training significantly improved their scores on knowledge, attitude, and practices subtests. In a follow-up survey, participants indicated that they had made ergonomic changes to their offices based on the training. Several participants indicated that the pain or discomfort that they had been experiencing was eliminated or reduced as a result of the training.  相似文献   
197.
The local impacts of industrial pollution can take many forms and—whilst uncertain in their scale, severity and distribution—are widely recognised. The question of who in society potentially experiences these impacts through living near to emission sources has been little explored, at least in the UK. This paper reports on a study carried out for the Environment Agency, which examined the distribution of sites coming within the Industrial Pollution Control (IPC) regime against patterns of deprivation. Our analysis provides evidence of a socially unequal distribution of IPC sites in England, with sites disproportionately located and clustered together in deprived areas and near to deprived populations. In discussing these results we emphasise the methodological limitations of this form of environmental justice analysis and the crucial differences between proximity, risk and impact. We also consider the distinction between inequality and injustice and the difficult policy questions which arise when evaluating evidence of environmental inequality, including potential grounds for policy intervention.  相似文献   
198.
Biodegradation and biosorption of acid anthraquinone dye   总被引:16,自引:0,他引:16  
The acid anthraquinone dye Tectilon Blue (TB4R) is a major coloured component from the aqueous effluent of a carpet printing plant in Northern Ireland. The aerobic biodegradation of TB4R has been investigated experimentally in batch systems, using three strains of bacteria, namely, Bacillus gordonae (NCIMB 12553), Bacillus benzeovorans (NCIMB 12555) and Pseudomonas putida (NCIMB 9776). All three strains successfully decolourised the dye, and results were correlated using Michaelis-Menten kinetic theory. A recalculation of the reaction rate constants, to account for biosorption, gave an accurate simulation of the colour removal over a 24-h period. Up to 19% of the decolorisation was found to be caused by biosorption of the dye onto the biomass, with the majority of the decolorisation caused by utilisation of the dye by the bacteria. The reaction rate was found to be intermediate between zero and first order at dye concentrations of 200-1000 mg/l.  相似文献   
199.
Book reviews     
Green Culture: environmental rhetoric in contemporary America. C. G. Herndl & S. C. Brown (Eds), 1996, Madison, WI, University of Wisconsin Press, 315 pp. ISBN 0 229 14990 0, £35.95 (hbk) ISBN 0 299 14994 3, £17.50 (pbk)

Earthtalk: communication empowerment for environmental action. S. A. Muir & T. L. Veenendall, 1996, Westport, CT, Praeger, Praeger Series in Political Communication, 233 pp. ISBN 0 275 953700 X, £47.95

Environmentalism and Cultural Theory. Kay Milton, 1996 London & New York, Routledge, 266 pp. ISBN 0 415 115529 9, £45.00 (hbk) ISBN 0 415 11530 2, £13.99 (pbk)

Local Environmental Struggles: citizen activism in the treadmill of production. Kenneth A. Gould, Allan Schnaiberg & Adam S. Weinberg, 1996, Cambridge University Press, 239 pp. ISBN 0 521 55519 1, £40.00 (hbk) ISBN 0 521 55521 3, £14.95 (pbk)

The Language of Environment: a new rhetoric. George Myerson & Yvonne Rydin, 1996 London, UCL Press, 264 pp. ISBN 1 85728 330 9, £35.00 (hbk) ISBN 1 85728 331 7, £11.95 (pbk)

Environmental Issues and Business: implications of a changing agenda. Sally Eden, 1996, Chichester, Wiley, ISBN 0 471 94872 1, £25.00

Green Shift: towards a green sensibility in architecture. John Farmer, edited by Kenneth Richardson, 1996, Oxford, Butterworth Architecture, with World-Wide Fund for Nature, ISBN 07506 15303

Lewis Mumford and the Ecological Region: the politics of planning. Mark Luccarelli, 1995, New York, Guilford Press, ISBN 1572300019, £19.95

The Ecology of Hope: communities collaborate for sustainability. Ted Bernard & Jora Young, 1997, East Haven, CT, New Society Publishers, 233 pp. ISBN 0 86571 355 33 (pbk)

Turning the Tide: integrated local area management for Australia's coastal zone. Valerie A. Brown, 1995, Canberra, Australia, Department of the Environment, Sport and Territories

Involving Communities in Forestry through Community Participation. Forestry Practice Guide 10, Forestry Commission

The Scope for Community Participation in Forest Management. A Report for the Forestry Commission and Scottish Office by Bill Slee, Gill Clark & Patrick Snowdon, £10 (£15 non UK)

The Role of Woodlands in Meeting Planning Objectives in Great Britain. A Report for the Forestry Commission by Professor Paul Selman  相似文献   
200.
Urinary gonadotropin peptide (UGP; β-core fragment), a major metabolite of human chorionic gonadotropin (hCG), was shown recently to be markedly elevated in Down syndrome pregnancy between 19 and 22 weeks of gestation. To confirm and extend this finding, we obtained maternal urine and matching maternal serum samples from 14 cases of Down syndrome and six other aneuploidies between 17 and 21 weeks of gestation. UGP was measured in all these samples and in 91 singleton control urines. Results were corrected for urinary creatinine level and expressed as multiples of the control median (MOM). hCG levels were assayed in all serum samples from the cases and compared with previously established reference values. The median UGP level in Down syndrome cases was 5.34 MOM (range 2.71–12.57); 88 per cent of the values were above the 95th centile of control levels after modelling. The median maternal serum hCG level for the same cases was 2.20 MOM (range 0.84–3.40); 36 per cent of the values were above the 95th centile. The level of UGP in every case including all other aneuploidies was higher than the comparable maternal serum hCG level. Elevated UGP measurements are strongly associated with fetal Down syndrome during the second trimester and could contribute to improved Down syndrome screening protocols that are more accessible and less expensive than are currently available.  相似文献   
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