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831.
Conserving Biological Diversity through Ecosystem Resilience 总被引:40,自引:0,他引:40
Brian Walker 《Conservation biology》1995,9(4):747-752
Confusion over the term ecological redundancy (Walker 1992) requires that the concept be clarified in order to advance the developing theory that maintaining ecosystem function conserves biological diversity. The species approach to conserving biological diversity assumes that the species in trouble are already identified. The ecosystem approach attempts to deal with the problem of conserving all the species in an ecosystem, including those not yet known. This is best achieved by ensuring that the ecosystem continues to function approximately as it has by maintaining its essential structure. Ecosystem stability (the probability of all species persisting) is enhanced if each important functional group of organisms (important for maintaining function and structure) comprises several ecologically equivalent species, each with different responses to environmental factors. In this sense ecological redundancy is good because it enhances ecosystem resilience, but functionally important groups (guilds, functional types) that have only one or very few species deserve priority conservation attention because their functions could be quickly lost with species extinctions. 相似文献
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835.
Jeanne L. Burton Brian W. McBride 《Journal of Agricultural and Environmental Ethics》1989,2(2):129-159
The intent of this article is to outline, integrate, and interpret relevant scientific, economic, and social issues of rbST technology that have contributed to the acceptance dilemma for this product. The public is divided into social groups, each with its own set of criteria on which they base rbSTs acceptability. Criteria for the scientific community may best be described as physiological. However, for consumers, criteria may be more practical, or procedural, including human health, animal welfare, environmental concerns, and overproduction. Because the business of dairy production depends on demand from the consuming public, the criteria for acceptance of rbST by producers largely reflects those of the consumers. Of necessity, producers are also critical of rbST from a business and animal improvement standpoint. Although this article demonstrates that rbST has met most physiological criteria for acceptance, the consuming public has treated the acceptance issue with forceful skepticism. The question this article addresses is, why? The authors comment that with rbST and other biotechnologies applied to agricultural animal production, it will be the responsibility of government health agencies, scientists, and manufacturers of the products to provide early, adequate, and honest public education. Attention to the concerns of the public may be the only means to prevent hysteria over this and future agricultural products of biotechnology and will, therefore, allow the public to form logical and thoughtful criteria assessments with respect to acceptance or rejection of each product. 相似文献
836.
Brian Gullett Lukas Oudejans Abderrahmane Touati Shawn Ryan Dennis Tabor 《Journal of Material Cycles and Waste Management》2008,10(1):32-37
A jet resonance-enhanced multiphoton ionization (REMPI) monitor was tested on a hazardous-waste-fired boiler for its ability
to determine concentrations of polychlorinated dibenzodioxins and dibenzofurans (PCDDs/Fs). Jet REMPI is a real-time instrument
capable of highly selective and sensitive (from parts per billion to parts per trillion) detection of a broad range of aromatic
compounds, including a number of air toxic compounds. The PCDD/F toxic equivalency (TEQ) value was derived from a predetermined
correlation (R
2 = 0.74) with monochlorobenzene (MClBz). This relationship was applied to nine subsequent jet REMPI on-line measurements of
MClBz and parallel, standard extractive sampling for PCDD/F TEQ. For high waste-firing rates, with a range of PCDD/F TEQ values
between 3.9 and 6.0 ng TEQ/m3, the TEQ values predicted by jet REMPI had a relative difference of 26% with the standard EPA Method 23 results. At low waste-firing
rates (0.9–1.6 ng TEQ/m3), the relative difference increased to 219%. This limited testing shows that jet REMPI has promise as an on-line diagnostic
monitor, providing feedback on the effects on PCDD/F emissions of operating parameter changes such as fuel feed interruptions
or air pollution control failures. 相似文献
837.
Petroleum mass removal from low permeability sediment using air sparging/soil vapor extraction: impact of continuous or pulsed operation 总被引:2,自引:0,他引:2
Air sparging and soil vapor extraction (AS/SVE) are innovative remediation techniques that utilize volatilization and microbial degradation to remediate petroleum spills from soils and groundwater. This in situ study investigated the use of AS/SVE to remediate a gasoline spill from a leaking underground storage tank (UST) in the low permeability, clayey soil of the Appalachian Piedmont. The objectives of this study were to evaluate AS/SVE in low permeability soils by quantifying petroleum mass removal rates, monitoring vadose zone contaminant levels, and comparing the mass extraction rates of continuous AS/SVE to 8 and 24 h pulsed operation. The objectives were met by collecting AS/SVE exhaust gas samples and vadose zone air from multi-depth soil vapor probes. Samples were analyzed for O2, CO2, BTEX (benzene, toluene, ethylbenzene, xylene), and total combustible hydrocarbon (TCH) concentrations using portable hand meters and gas chromatography. Continuous AS/SVE was effective in removing 608 kg of petroleum hydrocarbons from low permeability soil in 44 days (14.3 kg day−1). Mass removal rates ranged from 2.6 times higher to 5.1 times lower than other AS/SVE studies performed in sandy sediments. BTEX levels in the vadose zone were reduced from about 5 ppm to 1 ppm. Ten pulsed AS/SVE tests removed 78 kg in 23 days and the mean mass removal rate (17.6 kg day−1) was significantly higher than the last 15 days of continuous extraction. Pulsed operation may be preferable to continuous operation because of increased mass removal and decreased energy consumption. 相似文献
838.
This article covers the strategic, organizational, and operational decisions involved in one automobile manufacturer's efforts to balance its goals of productivity and high quality with the more elusive goal of environmental responsibility. The case material is based on the real-life experiences of Honda of America's two manufacturing plants in East Liberty and Marysville, Ohio. The case unfolds as the environmental manager in charge of the two plants faces the pending visit of her corporate boss from Tokyo, who has made it clear that environmental issues are of growing importance in Honda's overall direction. ISO 14000, the new environmental quality standards being adopted by some other manufacturers, serves as a focusing issue for the environmental manager's thinking, but this issue is really representative of a wider challenge facing the Ohio plants: balancing Honda's core mission of producing the best cars at the lowest cost possible, and being a responsible actor in the environmental arena. Complicating this challenge, the environmental manager has to negotiate another tension common in global manufacturing firms today: balancing the influence of Honda's corporate headquarters in Japan with the local and regional context at its American plant sites. 相似文献
839.
Tapping the leakages: Methane losses, mitigation options and policy issues for Russian long distance gas transmission pipelines 总被引:1,自引:0,他引:1
Stefan Lechtenbhmer Carmen Dienst Manfred Fischedick Thomas Hanke Roger Fernandez Don Robinson Ravi Kantamaneni Brian Gillis 《International Journal of Greenhouse Gas Control》2007,1(4):387-395
The Russian natural gas industry is the world's largest producer and transporter of natural gas. This paper aims to characterize the methane emissions from Russian natural gas transmission operations, to explain projects to reduce these emissions, and to characterize the role of emissions reduction within the context of current GHG policy. It draws on the most recent independent measurements at all parts of the Russian long distance transport system made by the Wuppertal Institute in 2003 and combines these results with the findings from the US Natural Gas STAR Program on GHG mitigation options and economics.With this background the paper concludes that the methane emissions from the Russian natural gas long distance network are approximately 0.6% of the natural gas delivered. Mitigating these emissions can create new revenue streams for the operator in the form of reduced costs, increased gas throughput and sales, and earned carbon credits. Specific emissions sources that have cost-effective mitigation solutions are also opportunities for outside investment for the Joint Implementation Kyoto Protocol flexibility mechanism or other carbon markets. 相似文献
840.
Enhanced biodegradation of azo dyes using an integrated elemental iron-activated sludge system: I. Evaluation of system performance. 总被引:1,自引:0,他引:1
Jennie Perey Saxe Brian L Lubenow Pei C Chiu Chin-Pao Huang Daniel K Cha 《Water environment research》2006,78(1):19-25
The objective of this research is to evaluate an integrated system coupling zero-valent iron (Fe(0)) and aerobic biological oxidation for the treatment of azo dye wastewater. Zero-valent (elemental) iron can reduce the azo bond, cleaving dye molecules into products that are more amenable to aerobic biological treatment processes. Azo dye reduction products, including aniline and sulfanilic acid, were shown to be readily biodegradable at concentrations up to approximately 25 mg/L. Batch reduction and biodegradation data support the proposed integrated iron pretreatment and activated sludge process for the degradation of the azo dyes orange G and orange I. The integrated system was able to decolorize dye solutions and yield effluents with lower total organic carbon concentrations than control systems without iron pretreatment. The success of the bench-scale integrated system suggests that iron pretreatment may be a feasible approach to treat azo dye containing wastewaters. 相似文献