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81.
The Coase theorem depends on a number of assumptions, among others, perfect information about each other's payoff function, maximising behaviour and zero transaction costs. An important question is whether the Coase theorem holds for real market transactions when these assumptions are violated. This is the question examined in this paper. We consider the results of Danish waterworks' attempts to establish voluntary cultivation agreements with Danish farmers. A survey of these negotiations shows that the Coase theorem is not robust in the presence of imperfect information, non-maximising behaviour and transaction costs. Thus, negotiations between Danish waterworks and farmers may not be a suitable mechanism to achieve efficiency in the protection of groundwater quality due to violations of the assumptions of the Coase theorem. The use of standard schemes or government intervention (e.g. expropriation) may, under some conditions, be a more effective and cost efficient approach for the protection of vulnerable groundwater resources in Denmark. 相似文献
82.
J. A. Raven D. I. Walker K. R. Jensen L. L. Handley C. M. Scrimgeour S. G. McInroy 《Marine Biology》2001,138(3):537-545
any sacoglossans (opisthobranch gastropods) have the potential for carbon acquisition from photosynthesis by plastids sequestered
from their macroalgal food as well as by ingestion, digestion and assimilation of the organic carbon derived from the alga.
A new method for obtaining a minimum estimate of the fraction of sacoglossan carbon supplied from photosynthesis by kleptoplastids
is suggested, based on the mass balance of stable carbon isotopes at the natural abundance level. The method involves comparison
of 13C/12C ratios in sacoglossans with those of the algae on which they are found. Differences in ratios between alga and sacoglossan
are used to give a minimum estimate of carbon acquisition by kleptoplasty, granted assumptions about the range of 13C/12C fractionation values which can occur for marine photolithotrophs. The new method is applied to several green (ulvophycean)
alga–sacoglossan associations from Rottnest Island, Western Australia, and the values compared with those obtained previously
by other means. The method suggests values of up to 0.6 of the total carbon input to the sacoglossans from photosynthesis
by their kleptoplastids. To improve the estimates of the minimum role of kleptoplastidy in the carbon nutrition of sacoglossans,
further information is needed: (1) on the fidelity of a given sacoglossan to a given algal individual (or species), (2) on
the 13C/12C ratio of the part of the alga ingested by the sacoglossan, and (3) on the allocation of dietary organic carbon and of kleptoplastidic
photosynthate to carbon lost in respiration, mucopolysaccharide production and gametes (and hence not sampled with the animal).
Received: 24 November 1999 / Accepted: 20 October 2000 相似文献
83.
Abamectin is a veterinary medicinal product with high efficiency against parasitics. This study evaluates the sublethal toxicity of abamectin to three groups of soil dwelling organisms (springtails, enchytraeids and earthworms). The reproduction of the two springtail species Folsomia fimetaria and Folsomia candida was significantly affected at abamectin concentrations of 0.25 and 0.5 mg/kg DW, respectively. Adults of especially F. candida were less sensitive. Abamectin had no effect on the survival of enchytraeids, whereas the number of juveniles was reduced at concentrations above 10 mg/kg. The EC10 values for reproduction were in the range of 0.05 mg/kg for springtails and 12.8 mg/kg for enchytraeids. Abamectin also had a significant effect on the reproduction of earthworms with an EC10 value of 0.06 mg/kg. However, no change in the survival and growth of juvenile earthworms was observed following 70 days of exposure. 相似文献
84.
Mark E. Jensen Roland L. Redmond Jeff P. Dibenedetto Patrick S. Bourgeron Iris A. Goodman 《Environmental monitoring and assessment》2000,64(1):197-212
The Little Missouri National Grasslands (LMNG) of western North Dakota support the largest permitted cattle grazing use within all lands administered by the USDA, Forest Service, as well as critical habitat for many wildlife species. This fact, coupled with the need to revise current planning direction for range allotments of the LMNG, necessitated that a broad-level characterization of ecosystem integrity and resource conditions be conducted across all lands within the study area (approximately 800,000 hectares) in a rapid and cost-effective manner. The approach taken in this study was based on ecological classifications, which effectively utilized existing field plot data collected for a variety of previous inventory objectives, and their continuous spatial projection across the LMNG by maps of both existing and potential vegetation. These two map themes represent current and reference conditions (existing vs. potential vegetation); their intersection allowed us to assign various ecological status ratings (i.e., ecosystem integrity and resource condition) based on the degree of departure between current and reference conditions. In this paper, we present a brief review of methodologies used in the development of ecological classifications, and also illustrate their application to assessments of rangeland health through selected maps of ecological status ratings for the LMNG. 相似文献
85.
86.
Michael J. McFarland Glenn R. Palmer Steve L. Rasmussen Micheal M. Kordich Dean A. Pollet James A. Jensen 《Journal of the Air & Waste Management Association (1995)》2013,63(7):1041-1051
Abstract The U.S. Department of Defense-approved activities conducted at the Utah Test and Training Range (UTTR) include both operational readiness test firing of intercontinental ballistic missile (ICBM) motors, as well as the destruction of obsolete or otherwise unusable ICBM motors through open burn/open detonation (OB/OD). Within the Utah Division of Air Quality, these activities have been identified as having the potential to generate unacceptable noise levels, as well as significant amounts of volatile organic compounds (VOCs). Hill Air Force Base, UT, has completed a series of field tests at the UTTR in which sound-monitoring surveillance of OB/OD activities was conducted to validate the Sound Intensity Prediction System (SIPS) model. Using results generated by the SIPS model to support the decision to detonate, the UTTR successfully disposed of missile motors having an aggregate net explosive weight (NEW) of 81,374 lb without generating adverse noise levels within populated areas. In conjunction with collecting noise-monitoring data, air emissions were collected to support the development of air emission factors for both static missile motor firings and OB/OD activities. Through the installation of 15 ground-based air samplers, the generation of combustion-fixed gases, VOCs, and chlorides was monitored during the 81,374-lb NEW detonation event. Comparison of field measurements to predictions generated from the US Navy energetic combustion pollutant formation model, POLU4WN, indicated that, as the detonation fire ball expanded, organic compounds, as well as CO, continued to oxidize as the combustion gases mixed with ambient air. VOC analysis of air samplers confirmed the presence of chloromethane, vinyl chloride, benzene, toluene, and 2-methyl-1-propene. Qualitative chloride analysis indicated that gaseous HCl was generated at low concentrations, if at all. 相似文献
87.
Michael J. McFarland Glenn R. Palmer Micheal M. Kordich Dean A. Pollet James A. Jensen Mitchell H. Lindsay 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1111-1121
Abstract The U.S. Department of Defense approved activities conducted at the Utah Test and Training Range (UTTR) include both operational readiness test firing of intercontinental ballistic missile motors as well as the destruction of obsolete or otherwise unusable intercontinental ballistic missile motors through open burn/open detonation (OB/ OD). Within the Utah Division of Air Quality, these activities have been identified as having the potential to generate unacceptable noise levels, as well as significant amounts of hazardous air pollutants. Hill Air Force Base, UT, has completed a series of field tests at the UTTR in which sound-monitoring surveillance of OB/OD activities was conducted to validate the Sound Intensity Prediction System (SIPS) model. Using results generated by the SIPS model to support the decision to detonate, the UTTR successfully disposed of missile motors having an aggregate net explosive weight (NEW) of 56,500 lbs without generating adverse noise levels within populated areas. These results suggest that, under appropriate conditions, missile motors of even larger NEW may be detonated without exceeding regulatory noise limits. In conjunction with collecting noise monitoring data, air quality data was collected to support the development of air emission factors for both static missile motor firings and OB/OD activities. Through the installation of 15 ground-based air samplers, the generation of combustion fixed gases, hazardous air pollutants, and chlorides were monitored during the 56,500-lb NEW detonation event. Comparison of field measurements to predictions generated from the U.S. Navy’s energetic combustion pollutant formation model, POLU4WN, indicated that, as the detonation fireball expanded from ground zero, organic compounds as well as carbon monoxide continued to oxidize as the hot gases reacted with ambient air. Hazardous air pollutant analysis of air samplers confirmed the presence of chloromethane, benzene, toluene, 1,2-propadiene, and 2-methyl-1-propene, whereas the absence of hydrogen chloride gas suggested that free chlorine is not generated during the combustion process. 相似文献
88.
89.
Nazaré Couto Janne Fritt-Rasmussen Pernille E. Jensen Mads Højrup Ana P. Rodrigo Alexandra B. Ribeiro 《Environmental science and pollution research international》2014,21(9):6221-6227
A 168-day period field study, carried out in Sisimiut, Greenland, assessed the potential to enhance soil remediation with the surplus heating from an incineration facility. This approach searches a feasible ex situ remediation process that could be extended throughout the year with low costs. Individual and synergistic effects of biostimulation were also tested, in parallel. An interim evaluation at the end of the first 42 days showed that biostimulation and active heating, as separate treatments, enhanced petroleum hydrocarbon (PHC) removal compared to natural attenuation. The coupling of both technologies was even more effective, corroborating the benefits of both techniques in a remediation strategy. However, between day 42 and day 168, there was an opposite remediation trend with all treatments suggesting a stabilization except for natural attenuation, where PHC values continued to decrease. This enforces the “self-purification” capacity of the system, even at low temperatures. Coupling biostimulation with active heating was the best approach for PHC removal, namely for a short period of time (42 days). The proposed remediation scheme can be considered a reliable option for faster PHC removal with low maintenance and using “waste heating” from an incineration facility. 相似文献
90.
Dennis Lindqvist Sören Jensen Lillemor Asplund 《Environmental science and pollution research international》2014,21(2):954-961
Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) of proposed natural origin have been detected throughout the food web of the Baltic Sea. Some OH-PBDEs have been shown to disrupt oxidative phosphorylation and the thyroid hormone system in exposed organisms. This paper describes an investigation into the fate of OH-PBDEs in the Baltic Sea’s predominant specie, the blue mussel. The main focus was on the conjugation of OH-PBDEs with lipophilic moieties (e.g., fatty acids) and the potential role this transformation mechanism may have in heavily exposed mussels in nature. Analytical methods were developed to accurately determine the concentrations of these conjugates in blue mussels collected on different occasions during the summer in a coastal area of the Baltic proper. The measured concentrations of conjugated OH-PBDEs were compared to those of the unconjugated parent compounds, and it was found that in some cases, the levels of the conjugated derivatives can be equal or even higher than the levels of the unconjugated OH-PBDEs. This is, to our knowledge, the first study on lipid-soluble OH-PBDE conjugates, and the first study to investigate the occurrence of such conjugates of halogenated phenolic compounds in environmentally exposed mussels. The mussels were also found to contain hydrolysable water-soluble derivatives of OH-PBDEs (such as e.g., glucuronic acid and/or sulfate conjugates etc.). These were tentatively determined to be of lower concentration (by up to an order of magnitude) than that of the OH-PBDEs which were conjugated with lipophilic moieties. 相似文献