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381.
R. M. Bennett J. Anderson R. J. P. Blaney 《Journal of Agricultural and Environmental Ethics》2002,15(2):187-202
An experimental survey was undertakento explore the links between thecharacteristics of a moral issue, the degree ofmoral intensity/moral imperative associatedwith the issue (Jones, 1991), and people'sstated willingness to pay (wtp) for policy toaddress the issue. Two farm animal welfareissues were chosen for comparison and thecontingent valuation method was used to elicitpeople's wtp. The findings of the surveysuggest that increases in moral characteristicsdo appear to result in an increase in moralintensity and the degree of moral imperativeassociated with an issue. Moreover, there was apositive link between moral intensity/moralimperative associated with an issue andpeople's stated wtp for policy to address theissue. The paper discusses the relevance of thefindings of the survey in the context of thedebate concerning the relationship betweenmoral and economic values and the use of thecontingent valuation method to estimatepeople's wtp of policy options with moraldimensions. 相似文献
382.
383.
Published scenarios of carbon emissions vary over a 40:1 range, and vary greatly even when the possible effects of future climate change policies are ignored. Differences in assumptions about how social and economic policies will affect the rates of economic growth throughout the world, population growth, international trade and investment, the rate of improvement in energy efficiency, and innovations and developments in non-carbon technologies are among the main reasons for such huge differences - alongside the considerable uncertainties that remain about the structural forms and parameters of the economic models used for making projections. The following analysis shows that a low carbon emissions scenario is fully consistent with developing countries achieving economic prosperity and the rich countries increasing theirs. It would depend on the emergence of non-carbon options, such as renewable energy, and this is indeed more likely to happen with favourable conditions for economic growth and innovation. 相似文献
384.
385.
This paper describes a quantitative investigation of relationships between the growth of phytoplankton, and climatic and hydrodynamci conditions in temperate fjords with marked tides, as exemplified by Puget Sound, Washington (USA). Algal growth in the open waters of the central basin of the Sound is dominated by a number of intense blooms beginning in late April or May and recurring throughout the summer. Rarely, and only briefly, does nitrate become exhausted. The phytoplankton production rate in the central basin of Puget Sound is about 465 g C m-2 year-1. During the springs of 1966 and 1967, oceanographic measurements were carried out at a mid-channel station with sufficient frequency to allow investigation of physical and biological processes with time scales of the order of a day. The principal investigative tool is a numerical model in which the hydrodynamical conditions are represented by an approximate analysis of the gravitational convection mode of circulation. Algal concentration is represented as a continous function of space and time in the model which ascribes changes in phytoplankton density to variations in photosynthetic and respiratory activity, algal sinking, grazing by herbivores, and to mixing and advection. Computations adequately reproduce the principal features of phytoplankton concentrations observed during 75 days and 35 days in the springs of 1966 and 1967, respectively. Numerical experiments assess the relative importance of various processes which govern the level of primary production in Puget Sound. It is concluded that phytoplankton growth is limited by a combination of factors, including vertical advection and turbulence, modulation of underwater light intensity by self-shading and inorganic particulates, sinking of algal cells, and occasional rapid horizontal advection of the population from the area by sustained winds. The high primary productivity of the Sound is due to intensive upward transport of nitrate by the estuarine mechanism. These results should be generally applicable to other temperate fjords because of the largely conventional choice of the biological functions. 相似文献
386.
William A. Searcy Rindy C. Anderson Stephen Nowicki 《Behavioral ecology and sociobiology》2006,60(2):234-241
A central question in animal communication research concerns the reliability of animal signals. The question is particularly relevant to aggressive communication, where there often may be advantages to signaling an exaggerated likelihood of attack. We tested whether aggressive signals are indeed reliable signals of attack in song sparrows (Melospiza melodia). We elicited aggressive signaling using a 1-min playback on a male’s territory, recorded the behavior of the male for 5 min, and then gave him the opportunity to attack a taxidermic mount of a song sparrow associated with further playback. Twenty subjects attacked the mount and 75 did not. Distance to the speaker was a significant predictor of attack for both the initial recording period and the 1 min before attack. For the initial recording period, none of the measures of singing behavior that we made was a significant predictor of attack, including song-type matching, type-switching frequency, and song rate. For the 1-min period immediately before attack, only the number of low amplitude “soft songs” was a significant predictor of attack. Although most aggressive signals contained little information on attack likelihood, as some models suggest should be the case, the unreliability of these signals was not caused by convergence of individuals on a single signaling strategy, as those models argue should occur. 相似文献
387.
To quantify diatom palaeoproduction responses to lake acidification, a whole-basin diatom accumulation rate was calculated for the small acidified lake Gaffeln, in the G?rdsj?n catchment in south-west Sweden. Changes in the relative frequency of diatom assemblages to acidification were typical of other lakes in the area, notably a decline in planktonic diatoms after approximately 1900 and increase in acid-tolerant benthic species (e.g. Eunotia spp. and Tabellaria binalis). Single deep-water cores could be used to infer past changes in diatom production because of changed sediment-microfossil deposition patterns, probably due to the development of a benthic algal mat in the littoral zone. The basin mean total diatom accumulation rate (based on eight cores) was approximately constant over the last 150 years, while planktonic diatoms decreased from 0.3 x 10(6) frustules cm(-2) year(-1) prior to 1900 to trace levels in the 1970s. There was, however, a corresponding increase in the accumulation of benthic diatoms over the same period, from 0.5 to 1 x 10(6) frustules cm(-2) year(-1) between 1950 and the present, together with changed community structure. The increase in benthic species probably reflects an expansion of the littoral zone as light transparency increased. 相似文献
388.
Mark G. Anderson 《Environmental management》1995,19(2):225-231
Seventy-one articles concerningLythrum salicaria (purple loosestrife), a European herb introduced to North America, were reviewed for evidence of utilization by North American
fauna and the effect of loosestrife on native plant species. In contrast to popular claims, 29 species of organisms were found
to utilize this plant, and no evidence of species declines due to purple loosestrife were found. Evidence that loosestrife
out-competes cattails and other plant species was found to be lacking or contradictory. Thus detailed, quantitative data are
needed to understand loosestrife's natural history, population dynamics, and impacts on native ecosystems if we are to effectively
manage this plant. 相似文献
389.
Dennis P. Letternmaier Dale E. Anderson Robert N. Brenner 《Journal of the American Water Resources Association》1984,20(4):473-481
ABSTRACT A method for systematic consolidation of a fixed station water quality monitoring network using dynamic programming is described. The approach utilizes a hierarchical structure; stations are allocated to what are termed primary basins on the basis of a weighted attribute score, and specific station locations within each primary basin are specified using a criterion based on stream order numbers. The method has been applied to the Municipality of Metropolitan Seattle (Metro) stream and river quality monitoring network. The results aided in a 1982 metro decision to reduce the scope of its fixed station monitoring from 81 to 47 stations, at an annual savings of approximately $33,000 per year exclusive of equipment depreciation and indirect costs. 相似文献
390.
ABSTRACT: Establishment of minimum stream flows on most streams in arid areas of the west will create serious water conflicts. Much economic activity is dependent upon a limited water supply. to attempt to reallocate water to maintain minimum flows will cause severe disruption to planned uses of water and to weak segments of the economy such as irrigated agriculture. 相似文献