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71.
In this paper, we present results from a survey on the perceived roles of organisations on the production and transfer of knowledge in Dutch soil policy. The results are interpreted by applying three theoretical perspectives to this relation: technical communities, epistemic communities and Mode 2 knowledge production. The main research results show that, since the perceived roles of organisations in some cases do not match the intended roles, or are inconsistent, communication of roles by organisations in the policy field is not effective. A second conclusion is that the respondents advocated an increase in interaction among policy levels and between knowledge production and policymaking. From the results, it seems that the Dutch soil policy field is on its way to a mode of socially robust knowledge production, where knowledge production, knowledge transfer and policymaking are integrated. In order to further this development, the paper provides recommendations on the further integration of science and policy concerning soil policy in the Netherlands.With respect to the methodology of survey research on the interaction between science and policy, the paper illustrates the importance of the professional identities of the respondents. The professional identities of the respondents are an important explanatory variable for the perceived roles of organisations. 相似文献
72.
73.
Female preference and sexual selection for male coloration in the guppy (Poecilia reticulata) 总被引:5,自引:0,他引:5
Astrid Kodric-Brown 《Behavioral ecology and sociobiology》1985,17(3):199-205
Summary Experiments were designed to determine the effects of male pigmentation patterns on female choice in guppies. When presented with a series of variably-colored males, females of different genetic strain consistently exhibited similar preferences (Tables 1 and 2), preferring those males with the greatest development of both carotenoid and iridescent pigments (Table 3). A partial rank correlation analysis of pigments of males indicates positive correlations between the iridescent and carotenoid pigments and also between melanins and showiness (Table 4). Only when either the carotenoid or iridescent pigments were held constant was there any effect of the other pigments on the ranking order of males by the females. Other pigments appear to be relatively unimportant in influencing female choice of males. These results indicate that females discriminate among males on the basis of color and that females of different strains prefer the same male colors rather than those characteristics of males of their own strain. The results support those models of sexual selection that hold that sexually selected traits honestly advertise the phenotypic and genetic qualities of males; they do not support models of runaway selection for particular male traits, such as first proposed by Fisher (1930). 相似文献
74.
We studied female guppies from two populations (Trinidad and Jemez Springs, New Mexico) to determine their mating preferences,
the degree of consensus among females for particular male phenotypes, and the variation among females for the types of traits
they prefer. We recorded the visual responses of 68 Trinidad and 10 Jemez females in paired male trials. The three sexually-selected
male traits quantified were the area of orange color and iridescence on the body, and display behavior. Females from the Trinidad
population agreed in their choice of males in three of the eight replicates, and this agreement was based on display rate
rather than male color patterns. Females from the Jemez population showed no agreement in their preferences of males. Mating
preferences of females varied both between populations and among females of a population. In both populations, female preferences
were based primarily on courtship intensity and only secondarily on color pattern. However, females from both populations
differed in the relative importance of orange color and iridescence. The fact that females differ in criteria for evaluating
males has important implications for selection and maintenance of color polymorphisms and for the interactions among multiple
secondary sexual traits of males in the guppy.
Received: 5 December 1995/Accepted after revision: 7 June 1996 相似文献
75.
76.
Henry P. Huntington Lawrence C. Hamilton Craig Nicolson Ronald Brunner Amanda Lynch Astrid E. J. Ogilvie Alexey Voinov 《Regional Environmental Change》2007,7(4):173-186
Human dimensions research focuses on the interrelationships between humans and the environment. To date, human dimensions
research in arctic regions has concentrated primarily on local events and contexts. As such, it complements analysis elsewhere
of adaptation and sustainable development within broad institutional, social, and environmental contexts. This paper reviews
five projects from the Human Dimensions of the Arctic System (HARC) initiative, established by the US National Science Foundation
in 1997. Common themes and findings are highlighted: climatic variations or change affect societies through interactions with
human activities; population dynamics provide key quantitative indicators of social impacts and well being; and specific impacts
and responses are the result of complex, context-sensitive interactions. Congruent approaches to the challenges of interdisciplinary
research are also identified: multivariate time plots aid the integration of data, retrospective and prospective studies are
part of a continuum and reinforce one another, comparative studies are essential for understanding general principles of human
dimensions, and arctic residents can play a vital role in research and action. 相似文献
77.
As with other construction materials, coal fly ash contains trace metals that can leach into the natural environment. As part of a broader effort to encourage appropriate coal combustion product use in infrastructure applications (e.g., road construction, stabilization, and structural fill), this study evaluated traditional and low‐cost adsorbent alternatives for their capacity to attenuate trace metals. Batch sorption tests were used as a preliminary screen for a wide variety of low cost (e.g., steel byproducts, rubber dust, and compost) and innovative materials (e.g., kudzu, biofilm, and pond weed) as well as conventional materials (activated carbon, alumina, and zeolites). The removal rates were demonstrated in this study by observing the calculated distribution coefficient (Kd) which were determined using a program called MATLAB. Limestone and steel byproducts were found to be particularly effective with large Kd values of 15,740, 1,520, and 540 L kg?1 for cadmium, chromium, and selenium and, for ladle refractory and mill scale, Kd values of 3,910, 670, and 1,760 L kg?1 were observed. Among the three metals tested for this study, it was observed that most low cost and innovative materials removed cadmium quite efficiently; however, the removal of selenium and chromium depended on the substrate and prevailing pH. In general, these results suggest that alternative materials may have relevance in niche applications where leaching is a concern that can be addressed through enhanced attenuation capacity via blending or layering of adsorbents. 相似文献
78.
A screening of relevant biomarkers was carried out in order to evaluate metabolic and cellular damages in European eels exposed to a non-point source contamination by persistent organic pollutants (POP) such as polycyclic aromatic hydrocarbons (PAH) and organochlorine compounds (OC) in a protected area, the Nature Reserve of Camargue (France). Investigations were focused on metabolic responses including detoxification mechanisms (biotransformation, antioxidant process), energy requirements and enzymatic membrane markers either involved in neuronal conduction (acetylcholinesterase, AChE) or in osmoregulation and energy metabolism (ATPases). The hepatic and muscular glycogen rates seemed to be suitable biomarkers as well as three hepatic activities involved in the protection against oxyradicals: catalase, glutathione peroxidase (SeGPx) and superoxide dismutases (SOD). The muscle and gill ATPases as well as the muscle and brain AChE showed more significant relevance in terms of biomarkers than the biotransformation enzymes: ethoxyresorufine-O-deethylase (EROD) and uridine diphospho-glucuronyl transferase (UDPGT). However, most of these enzymatic activities depend on numerous abiotic factors, which must be taken into account in such a biomarker assessment approach. Our study provides some conclusive elements to approve the use in situ of biomarkers developed from laboratory studies. It also raises a question regarding the location of contaminant impregnation in fish organ, in relation with age, development status or mode of contamination, and its influence on biomarker response. If the relevance of membrane indicators is confirmed, this study provides an original statement of the extent of the ecotoxicological threat for the aquatic species in a protected area, due to the occurrence of POP in the cell membranes. 相似文献
79.
Rudolf Brenneis Hubertus Wichmann Regina Sprenger Astrid Eickhoff Ralf Bock Tina Dettmer Burkhard Baeck Christian Reger Müfit Bahadir 《Environmental Sciences Europe》2006,18(2):95-101
Aims and Scope
Compared to mineral oil products, cooling lubricants based on fatty acid esters have technological advantages. Moreover, they are more environmentally compatible and make a contribution to a sustainable economy. Nevertheless, they are rarely applied in practice, because of their comparably high price, that is based on raw-material and synthesis costs. Alternatives concerning raw-materials and synthesis pathways are considered and properties of resulting ester products are compared.Methods
The investigations aimed at three fatty acid-2-ethyl-hexylesters that were synthesized in an enzymatic-catalytic routine based on peanut oil, suet, and waste edible fat and at esters that were conventionally produced from animal and plant fats and 2-ethyl-1-hexanol. Physical properties, fatty acid patterns, contents of free fatty acids, as well as oxidative and hydrolytic stabilities were determined. Thermolysis experiments were performed.Results
The physical properties of the seven esters, density, viscosity, pourpoint, and flash point, were comparable and gave reason for the assumption, that the products could be used as basis oils in lubricant formulations. Hydrolysis stabilities of the esters were high and thermal stress did not point at high potential of hazardous compounds formation. Especially the enzymatic-catalytically produced esters showed deficits concerning oxidation stabilities and free fatty acid contents.Outlook
For practice it will be necessary to define minimum qualities for raw-materials and resulting ester oils to be used as lubricant basis oils. Moreover, processes have to be developed, that yield high quality ester products from waste edible and animal fats without loosing the advantage of low-cost raw-materials by high production and refinement costs. Surely, one contribution is the further development of the energy-saving enzymtic alcoholysis for ester production. 相似文献80.