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101.
This paper examines some of the organizational and behavioural consequences of uncertainty through consideration of a case study. An industrial firm and its problems are described and an attempt is made to understand the origins of the situation using a systems analysis which draws on constructs from the structural, the behavioural and the ‘bureaucratic’ traditions within organization theory. The analysis demonstrates: that the problems are interrelated and stem from the structural arrangements in the firm which are unable to cope with the prevailing uncertainties; that the behavioural difficulties may be seen as manifestations of the underlying structural/environmental mismatch; and, that the problems are exacerbated by apparently logical but paradoxically inappropriate managerial choices and responses. The implications of this study for theory, practice and method are discussed. 相似文献
102.
Biodiversity across a Rural Land-Use Gradient 总被引:6,自引:0,他引:6
Jeremy D. Maestas § Richard L. Knight † Wendell C. Gilgert‡ 《Conservation biology》2003,17(5):1425-1434
103.
Development and characterization of complex particles for delivery of amino acids to early marine fish larvae 总被引:1,自引:0,他引:1
Complex particles (CP), zein microbound particles and lipid-spray beads (LSB) were prepared and their performances were compared for delivering glycine and a mixture of free amino acids (FAA; alanine, glycine, leucine, serine and tyrosine) to early fish larvae. Measures of performances of microparticles included inclusion, encapsulation, retention and delivery efficiencies in addition to T50 (time to 50% retention) values. CP were prepared containing LSB and a defined dietary mixture that were bound together with zein. CP had significantly higher retention and delivery efficiencies for FAA compared to those of zein microbound particles. Free LSB had higher retention efficiencies for particulate glycine compared with CP, possibly due to differences in suspension characteristics. Free LSB clumped and floated when suspended in water, negatively affecting their acceptability by fish larvae; therefore, LSB should be incorporated into CP for more effective delivery of amino acids. There was a significant inverse correlation between retention efficiencies and solubilities of FAA encapsulated in CP. After 1 h of aqueous suspension, highest retention (44%) and delivery efficiencies (20.3 mg tyrosine g–1 particle) were achieved with tyrosine. T50 values indicated 50% of the initial tyrosine in CP was still available after 36.7 min of suspension in water. Furthermore, CP can deliver FAA to marine fish larvae based on the results of feeding studies in which CP were digested by 3-day-old clownfish larvae; therefore, this particle type could be a valuable tool in studies of larval fish nutrition.Communicated by R.J. Thompson, St. Johns 相似文献
104.
Very low maternal serum alpha-fetoprotein (MSAFP) levels (<10 ng/mL) are known to be associated with non-viable pregnancies, including conditions such as fetal death, molar pregnancies, and non-pregnancies. There has not been agreement, however, as to whether very low MSAFP levels indicate already existing fetal deaths or are actually predictive. We analysed 230 pregnancies with MSAFP levels <10 ng/mL from among 15 807 women (1.5 per cent) screened consecutively during a three-year period and identified 26 non-viable pregnancies, 22 of which were diagnosed sonographically as part of the screening process (17 missed abortions, 3 blighted ova, 2 non-pregnancies). Furthermore, 20 of these 22 pregnancies were associated with essentially undetectable MSAFP levels (<5 ng/mL). Our data indicate that pregnancies with MSAFP values <5 ng/mL are the group most strongly associated with fetal non-viability and that very low MSAFP values are not strongly predictive for fetal death. 相似文献
105.
Pollard SJ Farmer JG Knight DM Young PJ 《Environmental pollution (Barking, Essex : 1987)》2002,117(1):5-8
Commercial mono- and polyclonal enzyme-linked immunosorbent assay (ELISA) systems were applied to the on-site analysis of weathered hydrocarbon-contaminated soils at a former integrated steelworks. Comparisons were made between concentrations of solvent extractable matter (SEM) determined gravimetrically by Soxhlet (dichloromethane) extraction and those estimated immunologically by ELISA determination over a concentration range of 2000-330,000 mg SEM/kg soil dry weight. Both ELISA systems tinder-reported for the more weathered soil samples. Results suggest this is due to matrix effects in the sample rather than any inherent bias in the ELISA systems and it is concluded that, for weathered hydrocarbons typical of steelworks and coke production sites, the use of ELISA requires careful consideration as a field technique. Consideration of the target analyte relative to the composition of the hydrocarbon waste encountered appears critical. 相似文献
106.
Influence of sediment on the fate and toxicity of a polyethoxylated tallowamine surfactant system (MON 0818) in aquatic microcosms 总被引:1,自引:0,他引:1
Wang N Besser JM Buckler DR Honegger JL Ingersoll CG Johnson BT Kurtzweil ML Macgregor J McKee MJ 《Chemosphere》2005,59(4):545-551
The fate and toxicity of a polyethoxylated tallowamine (POEA) surfactant system, MON 0818, was evaluated in water-sediment microcosms during a 4-d laboratory study. A surfactant solution of 8 mg l(-1) nominal concentration was added to each of nine 72-l aquaria with or without a 3-cm layer of one of two natural sediments (total organic carbon (TOC) 1.5% or 3.0%). Control well water was added to each of nine additional 72-l aquaria with or without sediment. Water samples were collected from the microcosms after 2, 6, 24, 48, 72, and 96 h of aging to conduct 48-h toxicity tests with Daphnia magna and to determine surfactant concentrations. Elevated mortality of D. magna (43-83%) was observed in overlying water sampled from water-only microcosms throughout the 96-h aging period, whereas elevated mortality (23-97%) was only observed in overlying water sampled from water-sediment microcosms during the first 24h of aging. Measured concentrations of MON 0818 in water-only microcosms remained relatively constant (4-6 mg l(-1)) during the 96-h period, whereas the concentrations in overlying water from microcosms containing either of the two types of sediment dissipated rapidly, with half-lives of 13 h in the 3.0% TOC sediment and 18 h in the 1.5% TOC sediment. Both toxicity and the concentration of MON 0818 in overlying water decreased more rapidly in microcosms containing sediment with the higher percent TOC and clay and with a higher microbial biomass. Mortality of D. magna was significantly correlated with surfactant concentrations in the overlying water. These results indicate that the toxicity of the POEA surfactant in water rapidly declines in the presence of sediment due to a reduction in the surfactant concentration in the overlying water above the sediment. 相似文献
107.
There is now overwhelming documentation of large-scale chemical recovery from surface water acidification in Europe, but to date there has been little documentation of biological recovery. Modelling studies based on current emission reduction plans in Europe indicate that there will be further chemical recovery. The uncertainties in these scenarios mainly relate to the future behavior of nitrogen in the ecosystem and the effects of climate change. Four major climate-related confounding factors that may influence the chemical and biological recovery process are: i) increased frequency and severity of sea-salt episodes; ii) increased frequency and severity of drought; iii) increased turnover of organic carbon; iv) increased mineralization of nitrogen. International cooperative work to abate acidification has so far been very successful, but there is still a long way to go, and many potential setbacks. It is essential that future development of water chemistry and aquatic biota in acidified waterbodies continue to be monitored in relation to further emission reductions of S and N and future effects of climate change. 相似文献
108.
Case Study and Retrospective: Aerobic Fixed Film Biological Treatment Process for 1,4‐Dioxane at the Lowry Landfill Superfund Site 下载免费PDF全文
Leslie Cordone Chris Carlson William Plaehn Timothy Shangraw David Wilmoth 《补救:环境净化治理成本、技术与工艺杂志》2016,27(1):159-172
An aerobic fixed film biological treatment system has been successfully treating recovered groundwater/landfill leachate containing 1,4‐dioxane, tetrahydrofuran (THF), and other constituents since 2003. The most likely mode of 1,4‐dioxane biotransformation is via a cometabolic pathway in the presence of THF. Pilot studies conducted during the process development phase established a design basis process loading factor of 0.6 g 1,4‐dioxane and THF (as chemical oxygen demand [COD])/g total solids per day and proved the efficacy of the process. Full‐scale design includes the use of three parallel moving bed bioreactors with effluent recycle capability. Removal efficiencies in excess of 98 percent have been documented for 1,4‐dioxane. Evolving operational challenges are associated with recent trends in 1,4‐dioxane pretreatment discharge limitations in combination with ongoing process optimization and increased influent flow rate conditions associated with seasonal precipitation patterns. ©2016 Wiley Periodicals, Inc. 相似文献
109.
110.
正We are very pleased to announce that five Associate Editors have joined the editorial team of the Journal of Environmental Sciences(JES).Professors/Drs.Yong Cai,Paul Lam,Jonathan Martin,Michael Plewa,and Po Keung Wong bring a wealth of expertise in environmental sciences.As preeminent scientists in their chosen areas of research,they have made outstanding contributions to the discipline of environmental 相似文献