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61.
Food and Environmental Virology - The hepatitis E virus (HEV) causes acute and chronic hepatitis in humans. The zoonotic HEV genotype 3 is mainly transmitted by consumption of contaminated food...  相似文献   
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Dominance assessment is important in mating competition across a variety of species, but little is known about how individuals’ own quality affects their assessment of potential rivals. We conducted two studies to test whether men’s own dominance affects their attentiveness to a putative dominance signal, vocal masculinity, when assessing competitors. Study I examined dominance ratings made by men in relation to their self-rated physical dominance. Study II examined dominance ratings made by men in relation to objective measures of their physical dominance, including size, strength, testosterone, and physical aggressiveness. Vocal masculinity strongly affected dominance ratings, but a man’s own dominance did not alter his attention to vocal masculinity when assessing dominance. However, men who rated themselves high on physical dominance rated the voices of other men lower on dominance and reported more sex partners (study I). Men with intermediate testosterone concentrations rated the voices of other men lower on dominance (study II). These results confirm the effect of vocal masculinity on dominance perceptions, provide further evidence that dominance is relevant to mating success, and shed new light on how men assess the dominance of rivals and potential allies. Our results suggest that attention to dominance signals may depend less on the observer’s own dominance in species with coalitional aggression, where individuals must assess others not only in relation to themselves but also in relation to each other. Among men, the effect of a deep, masculine voice on perceptions of dominance appears to be robust and unmediated by the formidability of the listener.  相似文献   
63.
J. Hiddink  R. Kock  W. Wolff 《Marine Biology》2002,140(6):1149-1156
The bivalve Macoma balthica migrates twice during the benthic part of its life cycle. During the spring migration (May-June), the newly settled spat (0-group) migrates to the nurseries in the high intertidal. Seven to nine months later, the bivalves migrate back to the low tidal flats and the subtidal (winter migration, 1-group). Both 0- and 1-group M. balthica use byssus threads for active pelagic migrations. As many M. balthica disappear during these migrations, we examined experimentally the importance of predation on 0- and 1-group M. balthica. Laboratory experiments using a circular aquarium determined predation rates on buried (no current) and drifting (current) 0- and 1-group M. balthica by several fish species (plaice, flounder, goby and whiting) and the shore crab. Under illuminated conditions, more M. balthica were consumed when migrating than when buried, whereas there was no difference between experiments in conditions of darkness. For the 0-group, predation rates on migrating and buried M. balthica in the dark were lower than in the light. The stomachs of pelagic fish in the Wadden Sea and Oosterschelde estuary did not contain M. balthica during winter migration. In the Wadden Sea, 1-group M. balthica primarily migrated at night. In conclusion, enhanced predation on drifting, as compared to buried, M. balthica may be the mechanism that explains enhanced mortality during migration in light, and may explain why M. balthica mainly migrates at night in the field. As we found no M. balthica in stomachs of pelagic fish, we do not know whether predation on byssus drifting M. balthica exists in the field. There are, however, some indications for fish predation on infaunal polychaetes during pelagic migrations.  相似文献   
64.
We monitored the short term behavioral and demographic responses of gray-tailed voles (Microtus canicaudus) to the reduction and fragmentation of their habitat. Our objectives were (1) to test whether animals perished or moved into remaining fragments after 70% of their habitat was removed; and (2) to test the null hypothesis that the social structure and demography of animals would not differ between habitats consisting of one large continuous fragment (625 m2), a mosaic of 25 small fragments (each 25 m2) separated by 4 m of bare ground, and control, unmanipulated habitats (1850 m2). We conducted the experiment in 12, 0.2-ha enclosures planted with alfalfa with four replicates for each of two manipulated treatments and a control. A 70% reduction in habitat did not adversely affect adult survival, reproductive rate, juvenile recruitment, or population size. However, an influx of unrelated females into habitat fragments resulted in decreased juvenile recruitment in those fragments. Voles from cleared habitat moved into the remaining habitat and did not measurably affect the resident population. Similarly, the demography of voles did not differ significantly among the large-fragment, small-fragment, and control enclosures. Peak density estimates based on the amount of habitat in each enclosure were 545 animals per hectare in control, 1056 in large-fragment, and 2880 in small-fragment enclosures. Reduced movement of animals among the small fragments was the most obvious effect of habitat fragmentation. Six percent of females and 15% of males moved among small fragments within a week compared to approximately 60% moving comparable distances in large-fragment and control enclosures. Rates of juvenile dispersal and sexual maturation declined throughout the summer on all treatments, were associated with season and density, and were only marginally associated with habitat loss and fragmentation. We conclude that at the time of habitat removal and fragmentation, populations were small enough to accommodate a 70% reduction in habitat and still continue to increase in numbers. The social system of gray-tailed voles was sufficiently flexible to accommodate an influx of animals to withstand densities> 1000 voles per ha. The behavioral and demographic features of gray-tailed voles are similar to those reported for other small mammals, thus confirming the use of voles for ecological model systems in habitat fragmentation studies.  相似文献   
65.
This paper reports on the results of a survey of environmental management and technical measures amongst almost 2000 European firms. Logit analysis is undertaken to determine the effects of firm characteristics, commercial conditions, perceived environmental impacts, expected benefits and stakeholder pressures on the probability of having an environmental management system in place. Subsequently, determinants of the likelihood of undertaking environmental actions in five environmental areas are estimated. There is a positive effect of environmental management on the likelihood of undertaking technical measures to reduce environmental impacts in some (but not all) areas, as well as a positive role for integrated environmental management strategies.  相似文献   
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Seven types of apparatus have been used to measure the quantum yields for direct phototransformation in water of 4 chemicals (pentachlorophenol; 2,4-dichlorophenol; 3,4-dichloroaniline; 4-nitrophenol) under polychromatic (12 laboratories) and monochromatic (3 laboratories) light, according to a common test protocol. The results with both types of light were in good agreement. The reproducibility and accuracy of quantum yields obtained with the ECETOC/University of Clermont-Ferrand apparatus with polychromatic light (6 laboratories) were similar to or better than those obtained with monochromatic light. A disadvantage of the method with polychromatic light is that the calculation is more complicated, but this can be overcome by the use of a desk-top computer. On the other hand experiments with polychromatic light permit the determination of quantum yields of substances of low photoreactivity.  相似文献   
68.
EU sustainable development indicators: An overview   总被引:2,自引:0,他引:2  
The European Union's commitment to sustainable development at the 1992 Earth Summit resulted in an EU‐wide sustainable development strategy, adopted in Gothenburg in 2001. This article presents an overview of the set of sustainable development indicators (SDIs) recently adopted by the European Commission to monitor, assess and revise the strategy. It provides a critical assessment of the current status of the indicator set, and reviews the main policy trends in the areas of the strategy through a brief analysis of headline indicators, placing energy and climate change issues in a broader perspective. Finally, the article compares the energy SDIs to the recent inter‐agency energy indicators for sustainable development (EISD), underlining their similarities as well as their different priorities and objectives. The article concludes that further research is needed to improve the SDI set and further explore the linkages between themes.  相似文献   
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