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Road-killed mammals, birds, and reptiles were collected weekly from highways in southern Brazil in 2002 and 2005. The objective
was to assess variation in estimates of road-kill impacts on species richness produced by different sampling efforts, and
to provide information to aid in the experimental design of future sampling. Richness observed in weekly samples was compared
with sampling for different periods. In each period, the list of road-killed species was evaluated based on estimates the
community structure derived from weekly samplings, and by the presence of the ten species most subject to road mortality,
and also of threatened species. Weekly samples were sufficient only for reptiles and mammals, considered separately. Richness
estimated from the biweekly samples was equal to that found in the weekly samples, and gave satisfactory results for sampling
the most abundant and threatened species. The ten most affected species showed constant road-mortality rates, independent
of sampling interval, and also maintained their dominance structure. Birds required greater sampling effort. When the composition
of road-killed species varies seasonally, it is necessary to take biweekly samples for a minimum of one year. Weekly or more-frequent
sampling for periods longer than two years is necessary to provide a reliable estimate of total species richness. 相似文献
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Waste incineration bottom ash and treated flue gas cleaning products mixed with 2.5% of cement (50 kg/m3) were tested in the laboratory in terms of compressive strength and tank leaching tests over a 64-day period. Although the material displayed lower mechanical strength than a reference concrete, the strength still was sufficient for use as a base layer for roads. The metal content in the incineration-residue-based specimens was up to 100 times higher than in the reference concrete, suggesting that the mixed waste incineration residue should be used only for dedicated purposes. The leaching of Cl and Na was increased by a factor of 20-100 from the incineration-residue-based specimens as compared to the reference, while the leaching of K, Ca and SO4 was increased by a factor of 2-10. The leaching of heavy metals was also higher from the incineration-residue-based specimens than from the reference with respect to Cu (50 times), Cd, Pb and Zn (5 times), but not with respect to Cr and Ni. The leaching curves did only allow for a closer evaluation of the leaching process in a few cases. The physical retention of the constituents seemed to be the same in the reference as in the incineration-residue-based specimens. Heavy metal leaching was limited by enhanced chemical retention in the incineration-residue-specimens as compared to the reference. Since no quality criteria in terms of leaching from a monolithic material are currently available, the leaching issue must be evaluated case by case. 相似文献
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Small enterprises face serious occupational health and safety challenges. The occupational risks are high and resources to control the risks are low. There is an ongoing search for ways that authorities and professional bodies can efficiently reach out to small enterprises with preventive measures. It has been suggested in the literature that accountants could act as intermediaries on health and safety. A pilot project was carried out in Denmark to test this possibility. State-authorized accountants were invited to training seminars to give them the necessary health and safety knowledge to provide advice to small enterprises. 164 accountants participated in the seminars and 74 accountants replied to a follow up questionnaire about their experience of advising their small enterprise clients about health and safety. Most of the accountants had actually given health and safety advice and for most of them it was a positive experience. However, they also faced constraints due to the relatively minor role health and safety played in their agendas with their clients and their own limited knowledge about health and safety even after taking part in the training seminars. This study concludes that it is possible for accountants to act as health and safety intermediaries, but that institutional support for the training activities is important to secure a broader application of this approach. 相似文献
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