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81.
A wind-directional sampler for determination of dust-deposition rates has been developed, enabling the measurement of dust-deposition caused by a specific source and, at the same time, providing information on the dust-deposition rate for the background area. The sampler is called METDUST. This paper describes the results of a field evaluation of the METDUST sampler. The field evaluation was performed in a village in Southern Jutland, Denmark, where complaints of dust-deposition had occurred close to a power plant with large stockpiles of coal. The results showed that, out of a 9-month period, increased dust-deposition occurred downwind from the stockpiles during 4 months. Episodes were identified by comparison with the background deposition rate. The METDUST sampler offers an opportunity to measure the dust-deposition rate contributed by the source and the background simultaneously. It can, therefore, be used by environmental authorities to identify the "likelihood of complaint" and to define a suitable guideline for the case in question.  相似文献   
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83.
All laboratory golden hamsters (Mesocricetus auratus) originated from a sibling pairing back in 1930. Due to this extreme founder event, domestic golden hamsters are presumed to be one of the most bottlenecked animal populations. Nevertheless, domestic hamsters show no obvious signs of inbreeding depression in commonly used breeding stocks. To explore the existence of potentially masked inbreeding effects, we compared the reproductive success of laboratory (lab) and wild-derived (wild) golden hamsters. We allowed oestrus females to mate consecutively with lab and wild males. The resulting offspring was genotyped using microsatellites to assess paternity. Finally, we compared male reproductive success to genetic variability, sexual behaviour and different sperm characteristics. Both hamster strains exhibited the expected large difference in genetic diversity (H wild =0.712±0.062 vs H lab =0.007±0.007. The reproductive success of wild males dramatically exceeded that of lab males (87% of pups were sired by wild males). Sexual behaviour of wild and lab males only varied in the number of long intromissions (intromissions without ejaculation at the end of the mating). No significant differences were observed in relation to mounting, ejaculation and intromission. There were also no apparent differences in sperm motility, velocity and density or testis histology between wild and lab hamsters. We conclude that the reduced reproductive success of lab males represents a hidden inbreeding effect, although its precise physiological cause remains unclear. These results provide first evidence for a major fitness disadvantage in captive golden hamsters.  相似文献   
84.
The Commission's recentinterpretation of the Precautionary Principleis used as starting point for an analysis ofthe moral foundation of this principle. ThePrecautionary Principle is shown to have theethical status of an amendment to a liberalprinciple to the effect that a state only mayrestrict a person's actions in order to preventunacceptable harm to others. The amendmentallows for restrictions being justified even incases where there is no conclusive scientificevidence for the risk of harmful effects.However, the liberal tradition has seriousproblems in determining when a risk of harm isunacceptable. Nevertheless, reasonable liberalarguments in favor of precaution can be basedon considerations of irreversible harm andgeneral fear of harm. But it is unclear whenthere considerations can be overridden.Within the liberal framework, the Commissionadvocates a so-called proportional version ofthe Precautionary Principle. This should beclearly distinguished from a welfare-basedapproach to precaution based on risk-aversiveweighing up of expected costs and benefits.However, in the last resort, the Commissiondoes seem to make a covert appeal to suchconsiderations.  相似文献   
85.
Is it legitimate for a business to concentrate on profits under respect for the law and ethical custom? On the one hand, there seems to be good reasons for claiming that a corporation has a duty to act for the benefit of all its stakeholders. On the other hand, this seems to dissolve the notion of a private business; but then again, a private business would appear to be exempted from ethical responsibility. This is what Kenneth Goodpaster has called the stakeholder paradox: either we have ethics without business or we have business without ethics. Through a different route, I reach the same solution to this paradox as Goodpaster, namely that a corporation is the instrument of the shareholders only, but that shareholders still have an obligation to act ethically responsibly. To this, I add discussion of Friedman’s claim that this responsibility consists in increasing profits. I show that most of his arguments fail. Only pragmatic considerations allow to a certain extent that some of the ethical responsibility is left over to democratic regulation.  相似文献   
86.
When it comes to conflict over risk management priorities in food production, a number of observers, including myself, have called for some sort of public deliberation as a means of resolving the moral disagreements underlying such conflicts. This paper asks how, precisely, such deliberation might be facilitated. It is shown that representative democracy and the liberal regulation that most Western democracies adhere to place important constraints on public deliberation. The challenge is to find forums for public deliberation that can operate within these constraints while still making a constructive contribution.  相似文献   
87.
More than 12 studies of different bottlenose dolphin populations, spanning from tropical to cold temperate waters, have shown that the species typically lives in societies in which relationships among individuals are predominantly fluid. In all cases dolphins lived in small groups characterised by fluid and dynamic interactions and some degree of dispersal from the natal group by both sexes. We describe a small, closed population of bottlenose dolphins living at the southern extreme of the species' range. Individuals live in large, mixed-sex groups in which no permanent emigration/immigration has been observed over the past 7 years. All members within the community are relatively closely associated (average half-weight index>0.4). Both male–male and female–female networks of preferred associates are present, as are long-lasting associations across sexes. The community structure is temporally stable, compared to other bottlenose dolphin populations, and constant companionship seems to be prevalent in the temporal association pattern. Such high degrees of stability are unprecedented in studies of bottlenose dolphins and may be related to the ecological constraints of Doubtful Sound. Fjords are low-productivity systems in which survival may easily require a greater level of co-operation, and hence group stability. These conditions are also present in other cetacean populations forming stable groups. We therefore hypothesise that ecological constraints are important factors shaping social interactions within cetacean societies.Communicated by D. Watts  相似文献   
88.
The cockle Cerastoderma (Cardium) edule (L.) ranges from NW Africa to northern Scandinavia. Abundance in shallow coastal sediment is often high, and it attracts commercial harvest. In this study, a complex genetic pattern has been revealed by mitochondrial DNA in 383 individuals from 19 sampling sites. Parsimony network analysis of 79 haplotypes identified two dominant central haplotypes separated by low divergence. One is characteristic for a homogenous southwestern group of populations from Africa to the British Isles. The other is characteristic for a heterogeneous northern group with a deviant Arctic population. At the entrance of the Baltic Sea, a mixture zone of the dominant haplotypes was found. The estimated population expansion time for the northern haplotype group predates that of the southwestern one, suggesting northern glacial refugia and a subsequent southern expansion of C. edule populations.  相似文献   
89.
Allocation of resources to growth and defense against herbivores crucially affects plant competitiveness and survival, resulting in a specific distribution of assimilates and defense compounds within plant individuals. Additionally, plants rarely experience stable environmental conditions, and adaptations to abiotic and biotic stresses may involve shifts in resistance to herbivores. We studied the allocation of phytochemicals in Brassica oleracea (Brussels sprouts) due to leaf age, drought stress and herbivore damage and assessed effects on two lepidopteran herbivores differing in diet breadth: the generalist Spodoptera littoralis and the specialist Pieris brassicae. Glucosinolates as secondary defense compounds and total nitrogen and carbon were quantified and linked to plant palatability, i.e., herbivore feeding preference. Herbivore responses were highly species-specific and partially related to changes in phytochemicals. Spodoptera littoralis preferred middle-aged leaves with intermediate levels of glucosinolates and nitrogen over young, glucosinolate and nitrogen rich leaves, as well as over old leaves, poor in glucosinolates and nitrogen. In contrast, P. brassicae preferred young leaves. Both species preferred severely drought-stressed plants to the well-watered control, although analyzed glucosinolate concentrations did not differ. Both S. littoralis and P. brassicae feeding induced an increase of indole glucosinolate levels, which may explain a reduced consumption of damaged plants detected for S. littoralis but not for P. brassicae. By revealing distinct, sometimes contrasting responses of two insect herbivores to within-plant and stress-mediated intraspecific variation in phytochemistry of B. oleracea, this study emphasizes the need to consider specific herbivore responses to understand and predict the interactions between herbivores and variable plants.  相似文献   
90.
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