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461.
The traditional vision of the role science should play in policy making is of a two stage process of scientists first finding
out the facts, and then policy makers making a decision about what to do about them. We argue that this two stage process
is a fiction and that a distinction must be drawn between pure science and science in the service of public policy. When science
is transferred into the policy realm, its claims to truth get undermined because we must abandon the open-ended nature of
scientific inquiry. When we move from the sphere of science to the sphere of policy, we pick an arbitrary point in the open-ended
scientific process, and ask our experts to give us the answer. The choice of the endpoint, however, must always be arbitrary
and determined by non-scientific factors. Thus, the two stages in the model of first finding the facts, and then making a
decision about what to do, cannot be clearly separated. The second stage clearly affects the first. This conclusion will have
implications about existing scientific policy institutions. For example, we advocate that the environmental assessment process
be radically overhauled, or perhaps even let go. It will be our position that ultimately a better model for the involvement
of scientists in public policy debates is that of being participants in particular interest groups (“hired guns”), rather
than as supposedly unbiased consultants to decision-makers. 相似文献
462.
Stephen A. Norton 《Water, Air, & Soil Pollution: Focus》2007,7(1-3):93-98
Pollution of the atmosphere with cadmium (Cd), mercury (Hg), and lead (Pb) is a consequence of human activities. Natural archives
are necessary to reconstruct the long-term history of metal deposition because accurate measurement of atmospheric deposition
is a recent accomplishment. Reconstructions require: (1) accurate determination of concentrations of elements and isotopes,
(2) accurate chronology of archives, and (3) archives that faithfully record atmosphere deposition. The most useful long-term
archives are accumulations of ice and snow, peat, and lake sediment. Quantification of Cd deposition is uncommon because of
its low concentration and substantial chemical mobility. Nonetheless, trends in peat and lake sediment are similar to those
of Hg and Pb since ca. 1800 a.d. Both Hg and Pb are relatively chemically immobile and thus the peat and lake archives are believed to record historic trends
of atmospheric deposition. Isotopic and concentration studies of Pb indicate a history of northern hemisphere atmospheric
pollution extending back prior to 0 a.d. Although measurements of Hg concentration are now routine, isotopic measurements are in their infancy. Some Hg pollution
sources have unique isotopic ratios, thereby contributing unique signals to the total Hg. Maximum accumulation rates of Hg
and Pb occur up to 10 years later than for Cd (1970s versus 1960s in eastern North America, perhaps slightly later in Europe).
By 2004, deposition of Cd, Hg, and Pb had declined from peak values in eastern North America more than 75, 75, and 90%, respectively. 相似文献
463.
Dairy manure application to soils can result in phosphorus (P)-related degradation of water quality. The P in these manure-impacted soils can be labile even years after abandonment and under conditions normally associated with high P stability. Failure of P to stabilize with time compounds the environmental consequences of dairy manure disposal, especially on sandy soils. The objectives of this study were to compare chemical characteristics of active and abandoned dairy manure-impacted soils and minimally impacted soils and to assess the continuous release of P in relation to sparingly soluble salts using repeated water extractions, X-ray diffraction, and speciation modeling of column leachates. Soil samples from Ap horizons were collected from nine highly manure-impacted (total P > 1000 mg P kg(-1) soil) areas on four active and five abandoned dairies and four minimally impacted soils (total P < 200 mg P kg(-1) soil). Soil extracts were analyzed for electrical conductivity (EC), soluble reactive phosphorus (SRP), Ca, Mg, Na, and K. The EC of the soil solutions decreased as active dairy > abandoned dairy > minimally impacted soils. Release of Mg and SRP were significantly correlated (r2 = 0.68) and did not decline after abandonment; Ca release was not correlated with SRP (r2 = 0.01), and declined significantly (p < 0.05) after abandonment. Speciation data from column leachates suggested that Mg-P phases and/or the most soluble Ca-P phases could control P solution activities. An implication of this study is that P stabilization via crystallization of calcium phosphates (even at near-neutral pH) may be preempted by Mg-P association. Thus, mechanisms to minimize P release may require P-retaining soil amendments or management of animal rations to eliminate Mg-P formation. 相似文献
464.
The debate between top-down and bottom-up planning has recently re-emerged in environmental management. Many commentators agree on the merits of comanagement, in which affected citizens and professional managers share responsibility for planning. Nevertheless, the manifold advantages of comanagement have not always been fully appreciated in environmental planning. For example, a group representing NGOs and academic institutions recently proposed an ecological corridor linking Algonquin Provincial Park in southern Ontario to the Adirondack Park in northern New York. This corridor, known as A2A, was designed to encourage the migration of wolves and other wildlife between the parks. Much of the land in A2A is private property. A survey of households, randomly scattered throughout the United States portion of the corridor, revealed that affected landowners had little knowledge of the proposal and no contact with its advocates. Many respondents were farmers who utilized land for livelihood. Other landowners enjoyed property for a variety of recreational purposes. Regardless of use, survey participants placed high value on the importance of conserving biological diversity. They also expressed great distrust toward restrictions that might be placed on their activities. In general, respondents felt very unsure about A2A, and they were uncertain about personal involvement in the planning process. Certain landowners indicated a willingness to have their land be included in an ecological corridor, despite not knowing about it before the survey was administered. These results suggest that A2A proponents have little to lose and much to gain by disseminating information locally and by embracing comanagement for further formulation of this plan. 相似文献
465.
466.
The proposed conversion from gasoline powered automobiles to diesel powered vehicels has prompted the Environmental Protection Agency to evaluate the potential health effects associated with exposure to diesel emissions. At present, there is no direct epidemiological link between this exposure and human health. Therefore, a research program was constructed to compare the health effects associated with diesel emissions with those from other emission sources for which epidemiological information was available. The emission sources chosen were cigarette smoke, roofing tar, and coke oven. An additional comparative emission source which was a gasoline catalyst engine. Respirable particles from a variety of combustion sources have the potential of being carcinogenic and mutagenic. The objective of these studies was to determine the relative biological activity of the organic material adsorbed on these particles in both in vitro mutagenesis and in vitro and in vivo bioassays. The organic extracts from the following series of emission sources were quantitatively bioassayed in a matrix of tests for their carcinogenic and mutagenic activity: (1) a light-duty Oldsmobile diesel 350 engine; (2) a heavy-duty Caterpillar diesel engine; (3) a light-duty Nissan engine; (4) a Volkswagen Rabbit diesel engine; (5) cigarette smoke; (6) roofing tar; (7) coke oven; and (8) a gasoline catalyst Mustang. The test matrix consisted of the following bioassay: reverse mutation in Salmonella typhimurium; mitotic recombination in Saccharomyces cerevisiae; DNA damage in Syrian hamster embryo cells (SHE); sister chromatid exchange in CHO cells; gene mutation in L5178Y mouse lymphoma cells, Balb/c 3T3 mouse embryo fibroblasts and CHO cells; viral enhancement of SHE cells; oncogenic transformation in Balb/c 3T3 cells; and skin tumor initiation in SENCAR and C57 black mice. The results of this test matrix are discussed. 相似文献
467.
Summary A detailed sound analysis of the Chick-adee call of the black-capped chickadee (Parus atricapillus) was performed in order to determine a basis for individual recognition and for imitation within winter flocks. During the winter of 1978–1979 members of five free-living black-capped chickadee flocks were uniquely marked for individual identification, and their calls were recorded in the field. Nested analysis of variance of temporal call parameters measured from sonagrams and spectral parameters from frequency spectra showed that there were significant differences between individuals within flocks for every parameter measured. There were significant differences between flocks in the frequency ranges 800–2,200 Hz and 4,000–5,300 Hz, in the spectral parameters bandwidth and maximum frequency, and in the duration of the Dee syllable and total call duration.Members of four of the five flocks were captured in December 1978 and held in aviaries segregated by original flock membership. In January 1979 the memberships of the three aviaries were rearranged to form experimental flocks. After one month, there were significant differences among the experimental flocks in the duration of the Dee syllable and total call duration. Convergence, as indicated by a significant decrease in variance among members (F-test), occurred in the experimental flock in Aviary 1 and was concentrated in the frequency ranges 1,300–1,800 and 6,200–6,900 Hz. The members of this experimental flock differed from each other in the number of 100 Hz frequency intervals within which each changed its own call.The Chick-a-dee call contains sufficient information that it can potentially be used by black-capped chickadees for individual recognition. In addition, both field and aviary data suggest that flock members converge in some call characteristics. Possible explanations of the social significance of vocal convergence in chickadee flocks are discussed. 相似文献
468.
469.
470.
Stephen Wright 《Resources Policy》1977,3(4):261-267
This paper argues that there has been insufficient analysis of long-term forecasting methods for resource demand at national level, compared with the attention devoted to supply factors. It suggests several important issues which need to be understood about the nature of demand projection and its pitfalls. Some significant and widely used resource demand models are summarized, all of which are particularly vulnerable to the uncertainty of macroeconomic modelling. 相似文献