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131.
132.
Nicolas H Highton Michael G Webb 《Journal of Environmental Economics and Management》1984,11(1):70-83
Reducing emissions of sulphur dioxide from the electricity industry in England and Wales would require application of abatement technology and raise electricity prices through increases in marginal supply costs. Capital and operating costs of alternative abatement techniques and their application under possible long-term investment and retirement plans for the industry are discussed. An approximate halving of projected emissions is found to have an effect of the order of 5% on prices under the existing tariff structure. Reductions of up to one-fifth are found to have an effect of under 1% on electricity prices. 相似文献
133.
Dufour's gland secretion may allow worker honeybees to discriminate between queen-laid and worker-laid eggs. To investigate this, we combined the chemical analysis of individually treated eggs with an egg removal bioassay. We partitioned queen Dufour's gland into hydrocarbon and ester fractions. The bioassay showed that worker-laid eggs treated with either whole gland extract, ester fraction or synthetic gland esters were removed more slowly than untreated worker-laid eggs. However, the effect only lasted up to 20 h. Worker-laid eggs treated with the hydrocarbon fraction were removed at the same rate as untreated eggs. The amount of ester which reduced the egg removal rate was far higher than that naturally found on queen-laid or worker-laid eggs, and at natural ester levels no effect was found. Our results indicate that esters or hydrocarbons probably do not function as the signal by which eggs can be discriminated. 相似文献
134.
ABSTRACTWhile environmental issues are among the most serious threats to human security, they tend to rank toward the bottom of Americans’ priorities for political action. To redress this, environmental organizations strategically frame their mobilization communications in an attempt to garner the public’s support. Advocacy research groups encourage the use of motivational, economic and personal frames because of their ability to mobilize support through distinct psychological processes: efficacy, psychological proximity and emotion. An experimental study is conducted that tests the extent to which these mechanisms mediate environmental frames’ effects on support for an environmental campaign. Results of this study lead to the conclusion that motivational frames are unable to elicit efficacy in the target audience, thus proving ineffectual at influencing attitudes or behaviors. Economic and personal frames are more successful, aligning the audience’s attitudes with the message and operating through psychological proximity, sadness and anger to induce behavioral support for the environmental campaign. 相似文献
135.
Population differentiation in female sex pheromone and male preferences in a solitary bee 总被引:2,自引:0,他引:2
Nicolas J. Vereecken Jim Mant Florian P. Schiestl 《Behavioral ecology and sociobiology》2007,61(5):811-821
Population differentiation in female mating signals and associated male preferences can drive reproductive isolation among
segregated populations. We tested this assumption by investigating intraspecific variation in female sex pheromone and associated
male odour preferences among distant populations in the solitary bee Colletes cunicularius (L.) by using quantitative gas chromatography and by performing field bioassays with synthetic blends of key sex pheromone
compounds. We found significant differences in sex pheromone blends among the bee populations, and the divergence in odour
blends correlated positively with geographic distance, suggesting that genetic divergence among distant populations can affect
sex pheromone chemistry. Our behavioural experiments, however, demonstrate that synthetic copies of allopatric female sex
pheromones were cross-attractive to patrolling males from distant populations, making reproductive isolation by non-recognition
of mating signals among populations unlikely. Our data also show that patrolling male bees from different populations preferred
odour types from allopatric populations at the two sites of bioassays. These male preferences are not expected to select for
changes in the female sex pheromone, but may influence the evolution of floral odour in sexually deceptive orchids of the
genus Ophrys that are pollinated by C. cunicularius males. 相似文献
136.
Jens Newig Nicolas W. Jager Elisa Kochskämper Edward Challies 《Journal of Environmental Policy & Planning》2019,21(3):213-227
ABSTRACTTheory on participatory and collaborative governance maintains that learning is essential to achieve good environmental outcomes. Empirical research has mostly produced individual case studies, and reliable evidence on both antecedents and environmental outcomes of learning remains sparse. Given conceptual ambiguities in the literature, we define governance-related learning in a threefold way: learning as deliberation; as knowledge- and capacity-building; and as informing environmental outputs. We develop nine propositions that explain learning through factors characterizing governance process and context, and three propositions explaining environmental outcomes of learning. We test these propositions drawing on the ‘SCAPE’ database of 307 published case studies of environmental decision-making, using multiple regression models. Results show that learning in all three modes is explained to some extent by a combination of process- and context-related factors. Most factors matter for learning, but with stark differences across the three modes of learning, thus demonstrating the relevance of this differentiated approach. Learning modes build on one another: Deliberation is seen to explain both capacity building and informed outputs, while informed outputs are also explained by capacity building. Contrary to our expectations, none of the learning variables was found to significantly affect environmental outcomes when considered alongside the process- and context-related variables. 相似文献
137.
Gilbert NL Goldberg MS Beckerman B Brook JR Jerrett M 《Journal of the Air & Waste Management Association (1995)》2005,55(8):1059-1063
The purpose of this study was to derive a land-use regression model to estimate on a geographical basis ambient concentrations of nitrogen dioxide (NO2) in Montreal, Quebec, Canada. These estimates of concentrations of NO2 will be subsequently used to assess exposure in epidemiologic studies on the health effects of traffic-related air pollution. In May 2003, NO2 was measured for 14 consecutive days at 67 sites across the city using Ogawa passive diffusion samplers. Concentrations ranged from 4.9 to 21.2 ppb (median 11.8 ppb). Linear regression analysis was used to assess the association between logarithmic concentrations of NO2 and land-use variables derived using the ESRI Arc 8 geographic information system. In univariate analyses, NO2 was negatively associated with the area of open space and positively associated with traffic count on nearest highway, the length of highways within any radius from 100 to 750 m, the length of major roads within 750 m, and population density within 2000 m. Industrial land-use and the length of minor roads showed-no association with NO2. In multiple regression analyses, distance from the nearest highway, traffic count on the nearest highway, length of highways and major roads within 100 m, and population density showed significant associations with NO2; the best-fitting regression model had a R2 of 0.54. These analyses confirm the value of land-use regression modeling to assign exposures in large-scale epidemiologic studies. 相似文献
138.
Treatment of olive mill effluents Part I. Organic matter degradation by chemical and biological processes--an overview 总被引:3,自引:0,他引:3
Olive mill effluents constitute a serious environmental problem in the Mediterranean Sea region due to the unique features associated with this type of agro-waste (i.e. seasonal and localized production, high and diverse organic load, low flow rates). Therefore, it is not surprising that research efforts have been directed towards the development of efficient treatment technologies including various physico-chemical and biological processes. This work reviews recent advances regarding olive mill effluent treatment with emphasis given on biological and chemical degradation processes. 相似文献
139.
Distance-based methods use point-to-point distances or random-location-to-point distances in a cloud of points to estimate
characteristics of the point pattern. One such characteristics is the density of points. The difficulty with distance-based
density estimators is that their distribution depends on the spatial pattern of points. In particular, the distribution of
distances is untractable for usual clustered patterns, that are often observed in natural systems. Here, we propose a density
estimator for clustered patterns, based on the random-location-to-pth-point distance X
p
. An approximate expression for the distribution function, F
p
, of X
p
was obtained by identifying the first two moments of the count of individuals in disks for a given point process with the
first two moments of a negative binomial distribution. The approximate expression of F
p
was then used to derive a maximum-likelihood estimator of the intensity of the point process. The quality of the approximation
of F
p
was assessed for homogeneous Poisson processes (for which the expression of F
p
is exact) and for Matérn processes. The intensity estimator based on Matérn processes was then used to estimate tree density
in a tree savanna in Mali, and it compared favorably with six robust estimators found in the literature. 相似文献
140.
Stephen J. Martin Nicolas Châline Falko Drijfhout Graeme R. Jones 《Behavioral ecology and sociobiology》2005,59(1):24-29
In queen-right honeybee colonies workers detect and eat the vast majority of worker-laid eggs, a behaviour known as worker policing. However, if a colony becomes permanently queen-less then up to 25% of the worker population develops their ovaries and lay eggs, which are normally reared into a final batch of males. Ovary development in workers is accompanied by changes in the chemical secretion of the Dufour's gland with the production of queen-like esters. We show that ester production increases with the period that the colony is queen-less. The increased ester production also corresponds to an increase in persistence of worker-laid eggs in queen-right colonies, since the esters somehow mask the eggs true identity. However, in a rare queen-less colony phenotype, workers always eat eggs indiscriminately. We found that the egg-laying workers in these colonies were unusual in that they were unable to produce esters. This apparently maladaptive egg eating behaviour is also seen in queen-less colonies prior to the appearance of egg-laying workers, a period when esters are also absent. However, the indiscriminate egg eating behaviour stops with the appearance of ester-producing egg-laying workers. These observations suggest that esters are providing some contextual information, which affects the egg eating behaviour of the workers. 相似文献