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81.
82.
OBJECTIVE: The study evaluated the accident risk of certain driving circumstances and driving motives among novice drivers. METHODS: Self-reported exposure and accidents according to driving circumstances and driving motives were compared between young (n = 6,847) and middle-aged (n = 942) male and female novice drivers. For young drivers, self-reported accidents were further compared to fatal accidents (n = 645) in terms of the driving conditions in which they occurred. The survey was conducted in 2002 and the questions regarding the quantity and quality of driving exposure and accidents covered the first four years of the novice drivers' driving career after licensing. Data on fatal accidents related to the period of 1990 to 2000. RESULTS: Leisure-time driving, driving just for fun, and driving with passengers and during evenings and at night was more typical for young drivers than for middle-aged drivers. For middle-aged drivers, the most typical driving was driving to or from work. Driving on errands was more typical for females than males. Nighttime driving was overrepresented in young drivers' self-reported and fatal accidents, compared to the share of young drivers' driving at night. Slippery road conditions were over-represented in young male drivers' self-reported accidents, but not in their fatal accidents, whereas for young females slippery road conditions seemed to increase the propensity of fatal accidents. CONCLUSIONS: The study concluded that some driving conditions increase the risk of certain types of accidents among certain driver groups, but not among all drivers. For example, slippery road conditions were overrepresented in young male drivers' minor (self-reported) accidents, but not in their fatal accidents. For young female drivers slippery road conditions seem to increase the propensity of fatal accidents. Driving circumstances are different in minor (self-reported) and fatal accidents. When drawing conclusions regarding accident risk, it is important to determine the seriousness of the accidents which take place.  相似文献   
83.
Toräng P  Ehrlén J  Agren J 《Ecology》2006,87(8):2113-2117
Population context should influence pollination success and selection on floral display in animal-pollinated plants because attraction of pollinators depends not only on the characteristics of individual plants, but also on the attractiveness of co-occurring conspecifics. The insect-pollinated herb Primula farinosa is polymorphic for inflorescence height. Natural populations may include both long-scaped plants, which present their flowers well above the soil surface, and short-scaped plants, with their flowers positioned close to the ground. We experimentally tested whether seed production in short-scaped P. farinosa varied with local morph frequency and surrounding vegetation height. In tall vegetation, short-scaped plants in polymorphic populations produced more fruit and tended to produce more seeds than short-scaped plants did in monomorphic populations. In low vegetation, population composition did not significantly affect fruit and seed output of short-scaped plants. The results suggest that long-scaped plants facilitate short-scaped plants in terms of pollinator attraction and that the facilitation effect is contingent on the height of the surrounding vegetation. The documented facilitation should contribute to the maintenance of the scape length polymorphism in ungrazed areas where litter accumulates and vegetation grows tall.  相似文献   
84.
This paper summarises the results of the EU funded MEAD project, an interdisciplinary study of the effects of atmospheric nitrogen deposition on the Kattegat Sea between Denmark and Sweden. The study considers emissions of reactive nitrogen gases, their transport, transformations, deposition and effects on algal growth together with management options to reduce these effects. We conclude that atmospheric deposition is an important source of fixed nitrogen to the region particularly in summer, when nitrogen is the limiting nutrient for phytoplankton growth, and contributes to the overall eutrophication pressures in this region. However, we also conclude that it is unlikely that atmospheric deposition can, on its own, induce algal blooms in this region. A reduction of atmospheric nitrogen loads to this region will require strategies to reduce emissions of ammonia from local agriculture and Europe wide reductions in nitrous oxide emissions.  相似文献   
85.
A naturally contaminated sediment was partially extracted with selective supercritical fluid extraction (SFE) to remove a fraction of supposedly bioavailable PCBs from the matrix. Eels (Anguilla anguilla) were cultured in systems with untreated and pre-extracted sediment, respectively, and it was shown that the SFE treatment selectively removed bioavailable PCBs from the sediment, since relative biota-to-sediment accumulation factors (BSAFs) for the eight studied PCB congeners were much lower in the pre-extracted than in the untreated system at the end of the study. Relative BSAF values decreased with about the same relative amount for all eight congeners, independent of the degree of chlorination and the initial concentration in the sediment. The results demonstrate the ability of SFE to selectively remove sediment-bound PCBs that are available for uptake by the eels, thus demonstrating the feasibility of using selective SFE to estimate bioavailability of PCBs in sediments.  相似文献   
86.
动物行为是动物福利的核心部分,是可持续的动物育种的基础.在驯化过程中,动物已在行为和一系列其它显著特性方面产生适应性.我们对原鸡和白莱亨蛋鸡(为产蛋而选,间接为产肉而选)的行为进行了比较.原鸡在群居、探索、抗捕食和进食试验方面表现出更积极的行为.对一只原鸡与白莱亨鸡杂交后代进行的定量特性位点(QTLs)基因组扫描显示,不同的特性具有一些明显的或启示性的QTLs.一些生产QTLs与行为QTLs相重合,表明生物多向性效应对育种显型的发展也许是重要的.我们定位了一种基因,它对成为啄毛行为受害者方面有强烈影响,而啄毛是一种有害的行为紊乱现象.现代基因学配以行为分析,也许有益于未来设计出更加可持续的育种方式,培育出耐力更强的动物.  相似文献   
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88.
Are elected politicians primarily motivated by holding office, thus choosing environmental policies accordingly? Or are they motivated by the chance to implement their preferred environmental policies? Do governors have character, in the sense that they promise and implement environmental policies consistent with their own preferences? To answer these questions, we study the differences in environmental spending across both re-electable and lame duck governors from the two main political parties. In our empirical analysis, we make use of parametric and non-parametric regression-discontinuity approaches. While re-electable governors do not set significantly different policies, lame duck governors do. We argue that in the area of environmental policy governors appear to be primarily office motivated and lack character.  相似文献   
89.
90.
ABSTRACT

The Norwegian urban growth agreement (UGA) is a governance platform combining transport-infrastructure development with land-use and transport policy. It is a policy package of measures involving network cooperation between national, regional and local government levels established to coordinate transport and land-use development. Shared responsibility for goal achievement, autonomy and learning and adaptation as new knowledge and experience arise are clear prerequisites for the UGAs. This makes it relevant to investigate the conditions for the UGAs to work as an adaptive governance strategy because their central features are in line with the attributes of adaptive governance. Further, adaptive governance is an approach to handle complex problems like transport development issues. The study shows that UGAs have several strengths in terms of autonomy and learning. However, the multi-level cooperation in the UGAs is framed by complex underlying structures of roles and powers, which challenge the working and legitimacy of the governance structures. Multi-level adaptive governance processes like the UGAs require attention to issues of power and legitimacy. Securing transparency and democratic anchorage is paramount in bringing such processes in line with the intended benefits of adaptive governance.  相似文献   
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