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921.
In settings where measurements are costly and/or difficult to obtain but ranking of the potential sample data is relatively easy and reliable, the use of statistical methods based on a ranked-set sampling approach can lead to substantial improvement over analogous methods associated with simple random samples. Previous nonparametric work in this area has been concentrated almost exclusively on the one- and two-sample location problems. In this paper we develop ranked-set sample procedures for the m-sample location setting where the treatment effect parameters follow a restricted umbrella pattern. Distribution-free testing procedures are developed for both the case where the peak of the umbrella is known and for the case where it is unknown. Small sample and asymptotic null distribution properties are provided for the peak-known test statistic.  相似文献   
922.
Projecting the consequences of warming and sea-ice loss for Arctic marine food web and fisheries is challenging due to the intricate relationships between biology and ice. We used StrathE2EPolar, an end-to-end (microbes-to-megafauna) food web model incorporating ice-dependencies to simulate climate-fisheries interactions in the Barents Sea. The model was driven by output from the NEMO-MEDUSA earth system model, assuming RCP 8.5 atmospheric forcing. The Barents Sea was projected to be > 95% ice-free all year-round by the 2040s compared to > 50% in the 2010s, and approximately 2 °C warmer. Fisheries management reference points (FMSY and BMSY) for demersal fish (cod, haddock) were projected to increase by around 6%, indicating higher productivity. However, planktivorous fish (capelin, herring) reference points were projected to decrease by 15%, and upper trophic levels (birds, mammals) were strongly sensitive to planktivorous fish harvesting. The results indicate difficult trade-offs ahead, between harvesting and conservation of ecosystem structure and function.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01616-9.  相似文献   
923.
The changing Arctic environment is affecting zooplankton that support its abundant wildlife. We examined how these changes are influencing a key zooplankton species, Calanus finmarchicus, principally found in the North Atlantic but expatriated to the Arctic. Close to the ice-edge in the Fram Strait, we identified areas that, since the 1980s, are increasingly favourable to C. finmarchicus. Field-sampling revealed part of the population there to be capable of amassing enough reserves to overwinter. Early developmental stages were also present in early summer, suggesting successful local recruitment. This extension to suitable C. finmarchicus habitat is most likely facilitated by the long-term retreat of the ice-edge, allowing phytoplankton to bloom earlier and for longer and through higher temperatures increasing copepod developmental rates. The increased capacity for this species to complete its life-cycle and prosper in the Fram Strait can change community structure, with large consequences to regional food-webs.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01667-y.  相似文献   
924.
The International Joint Commission has recently completed a five-year study (2000–2005) to review the operation of structures controlling the flows and levels of the Lake Ontario – St. Lawrence River system. In addition to addressing the multitude of stakeholder interests, the regulation plan review also considers environmental sustainability and integrity of wetlands and various ecosystem components. The present paper outlines the general approach, scientific methodology and applied management considerations of studies quantifying the relationships between hydrology and wetland plant assemblages (% occurrence, surface area) in Lake Ontario and the Upper and Lower St. Lawrence River. Although similar study designs were used across the study region, different methodologies were required that were specifically adapted to suit the important regional differences between the lake and river systems, range in water-level variations, and confounding factors (geomorphic types, exposure, sediment characteristics, downstream gradient of water quality, origin of water masses in the Lower River). Performance indicators (metrics), such as total area of wetland in meadow marsh vegetation type, that link wetland response to water levels will be used to assess the effects of different regulation plans under current and future (climate change) water-supply scenarios.The Canadian Crown reserves the right to retain a non-exclusive, royalty free licence in and to any copyright.  相似文献   
925.
This is the first in a series of five articles describing the applicability, performance, and cost of technologies for the remediation of contaminated soil and water at wood preserving sites. Site‐specific treatability studies conducted under the supervision of the United States Environmental Protection Agency (US EPA), National Risk Management Research Laboratory (NRMRL), from 1995 through 1997 constitute much of the basis for the evaluations presented, although data from other treatability studies, literature sources, and actual site remediations have also been included to provide a more comprehensive evaluation of remediation technologies. This article provides an overview of the wood preserving sites studied, including contaminant levels, and a summary of the performance of the technologies evaluated. The subsequent articles discuss the performance of each technology in more detail. Three articles discuss technologies for the treatment of soils, including solidification/stabilization, biological treatment, solvent extraction and soil washing. One article discusses technologies for the treatment of liquids, water and nonaqueous phase liquids (NAPLS), including biological treatment, carbon adsorption, photolytic oxidation, and hydraulic containment. The reader should be aware that other technologies including, but not limited to, incineration, thermal desorption, and base catalyzed dehalogenation, also have application for treating contaminants on wood preserving sites. They are not discussed in these five articles since the focus was to evaluate lesser known and hopefully lower cost approaches. However, the reader should include consideration of these other technologies as part of any evaluation or screening of technologies applicable to remediation of wood preserving sites.  相似文献   
926.
This article discusses the use of solidification/stabilization (S/S) to treat soils contaminated with organic and inorganic chemicals at wood preserving sites. Solidification is defined for this article as making a material into a freestanding solid. Stabilization is defined as making the contaminants of concern nonmobile as determined from a leaching test. S/S then combines both properties. For more information on S/S in general the reader should refer to other publications (Connors, J.R. [1990]). Chemical fixation and solidification of hazardous wastes. New York: Van Nostrand Reinhold; US Environmental Protection Agency. [1993a]. Engineering bulletin solidification/stabilization of organics and inorganics (EPA/540/S‐92/015); Wiles, C.C. [1989]. Solidification and stabilization technology. In H.M. Freeman [Ed.], Standard handbook of hazardous waste treatment and disposal. New York: McGraw Hill) as this article addresses only wood preserving sites and assumes basic knowledge of S/S processes. For a more general discussion of wood preserving sites and some other remedial options, the reader may wish to refer to a previous EPA publication (US Environmental Protection Agency. [1992a]. Contaminants and remedial options at wood preserving sites [EPA/600/R‐92/182]). This article includes data from the successful remediation of a site with mixed organic/inorganic contaminants, remediation of a site with organic contaminants, and detailed treatability study results from four sites for which successful formulations were developed. Included are pre‐ and post‐treatment soil characterization data, site vaines. ileizdot‐ names (in some cases), treatment formulas used (generic aridproprietary), costs, recommendations, and citatioiis to inore detailed refer‐ en ces. The data presen ted iiidica te that dioxins, pentachlorophepi 01 (PCP), creosote, polycyclic aromatic hydrocarbom (PAHsI, and metals can be treated at moderate cost by the use of S/S techuologp.  相似文献   
927.
A general theory known as the waste reduction (WAR) algorithm has been developed to describe the flow and the generation of potential environmental impact through a chemical process. The theory defines indexes that characterize the generation and the output of potential environmental impact from a process. The existing theory has been extended to include the potential environmental impact of the energy consumed in a chemical process. Energy will have both an environmental impact as well as an economic impact on process design and analysis. Including energy into the analysis of environmental impact is done by re-writing the system boundaries to include the power plant which supplies the energy being consumed by the process and incorporating the environmental effects of the power plant into the analysis. The effect of this addition on the original potential impact indexes will be discussed. An extensive engineering economic evaluation has been included in the process analysis which inherently contains the cost of the consumed energy as an operating cost. A case study is presented which includes a base process design and two modifications to the base design. Each design is analyzed from an economic perspective and an environmental impact perspective. The environmental impact analysis is partitioned into the impacts of the non-product streams and the impacts of the energy generation/consumption process. The comparisons of these analysis procedures illustrate the consequences for decision making in the design of environmentally friendly processes.  相似文献   
928.
Using integrating NO2 diffusion dosimeters, personal, indoor and outdoor exposures were measured for nine families in Topeka, Kansas. NO2 exposures in homes that used gas for cooking were clearly different from those in homes that used electricity. The gas-cooking homes had indoor levels three times the outdoor levels. Members of the gas-cooking households had levels twice those of electric-cooking families and twice the outdoor levels. A linear model that includes outdoor concentrations and stove types explains 77% of the variance in observed NO2 exposure. The differential NO2 exposures in homes with and without gas stoves should be considered in epidemiologic studies of the health effects of air pollution.  相似文献   
929.
930.
Photobacterium phosphoreum is a marine bacterium which is used extensively as a bioluminescent indicator of pollutants, where the presence of toxicants diminishes light output. To evaluate the utility of cell immobilisation in continuous toxicity testing, the sensitivity of P. phosphoreum to five gelling agents was evaluated relative to the retention of bioluminescence in 3% NaCl-glycerol suspensions. Following storage at 4°C, the control cultures retained light output for up to 2 weeks before significant decline; alginate-glycerol suspensions were stable for up to 4 weeks and bioluminescence was detectable for up to 6 weeks. Cells stored in agar were no more stable than the control, whereas cells gelled in agarose and low-melting point agarose showed a significant decline in bioluminescence within 2 weeks of storage. Bioluminescence was totally retained in alginate-glycerol suspensions stored at −80°C for up to 12 weeks. P. phosphoreum was successfully immobilised in strontium alginate and showed a dose-related response to four of the five heavy metal ions, SDS and pentachlorophenol tested when responses were followed over a time-course. A flow-through system for Sr-alginate immobilised cells was developed and conditions for operation were optimised. When cells were exposed to a pulse of 4-nitrophenol or salicylate then the nutrient feed continued, bioluminescence declined in response (pulse of 4–6 min) to these pollutants then recovered to a new stable rate of decline which was faster than the pre-exposure rate. These results demonstrate the potential of using immobilised P. phosphoreum in a continuous flow-through system for real-time environmental monitoring of water quality.  相似文献   
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