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181.
Trace-metal distribution in tissues of the shrimp Pleoticus muelleri Bate from the Patagonian region, Argentina, was related to sex, size and physiological condition. Concentrations of cadmium, copper, manganese and zinc were determined in the digestive gland, male reproductive system and muscle of adult specimens. Significant (p<0.01) sex-dependent differences in mean metal concentrations (g g-1 wet wt) were found in the following tissues of males and females, respectively: digestive gland, Cu, 82.9 and 30.8; Zn, 32.5 and 44.9; reproductive system, Zn, 12.8 and 38.6; Mn, 1.7 and 3.1; Cd, 0.29 and 0.58. Metal levels of muscle showed no significant differences between sexes. Cadmium was not detected in muscle, suggesting that its incorporation into this tissue was strictly regulated. Metal concentrations in the male reproductive system were in general weakly correlated (0.001<p<0.05) with either body size or the concentration of metals in the digestive gland. The developing ovary incorporated substantial amounts of zinc, while cadmium and copper levels decreased at proportional rates (p<0.001). The patterns of the variations in the concentrations of these metals in the ovary strongly suggested that a regulatory mechanism operated throughout oogenesis. Manganese was not involved in this presumptive mechanism. The results of this study are discussed in terms of concentrations and in absolute amounts for standardized individuals.  相似文献   
182.
Despite the widespread application of photochemical air quality models (AQMs) in U.S. state implementation planning (SIP) for attainment of the ambient ozone standard, documentation for the reliability of projections has remained highly subjective. An "idealized" evaluation framework is proposed that provides a means for assessing reliability. Applied to 18 cases of regulatory modeling in the early 1990s in North America, a comparative review of these applications is reported. The intercomparisons suggest that more than two thirds of these AQM applications suffered from having inadequate air quality and meteorological databases. Emissions representations often were unreliable; uncertainties were too high. More than two thirds of the performance evaluation efforts were judged to be substandard compared with idealized goals. Meteorological conditions chosen according regulatory guidelines were limited to one or two cases and tended to be similar, thus limiting the extent to which public policy makers could be confident that the emission controls adopted would yield attainment for a broad range of adverse atmospheric conditions. More than half of the studies reviewed did not give sufficient attention to addressing the potential for compensating errors. Corroborative analyses were conducted in only one of the 18 studies reviewed. Insufficient attention was given to the estimation of model and/or input database errors, uncertainties, or variability in all of the cases examined. However, recent SIP and policy-related regional modeling provides evidence of substantial improvements in the underlying science and available modeling systems used for regulatory decision making. Nevertheless, the availability of suitable databases to support increasingly sophisticated modeling continues to be a concern for many locations. Thus, AQM results may still be subject to significant uncertainties. The evaluative process used here provides a framework for modelers and public policy makers to assess the adequacy of contemporary and future modeling work.  相似文献   
183.
In order to carry out efficient traffic and air quality management, validated models and PM emission estimates are needed. This paper compares current available emission factor estimates for PM10 and PM2.5 from emission databases and different emission models, and validates these against eight high quality street pollution measurements in Denmark, Sweden, Germany, Finland and Austria.The data sets show large variation of the PM concentration and emission factors with season and with location. Consistently at all roads the PM10 and PM2.5 emission factors are lower in the summer month than the rest of the year. For example, PM10 emission factors are in average 5–45% lower during the month 6–10 compared to the annual average.The range of observed total emission factors (including non-exhaust emissions) for the different sites during summer conditions are 80–130 mg km−1 for PM10, 30–60 mg km−1 for PM2.5 and 20–50 mg km−1 for the exhaust emissions.We present two different strategies regarding modelling of PM emissions: (1) For Nordic conditions with strong seasonal variations due to studded tyres and the use of sand/salt as anti-skid treatment a time varying emission model is needed. An empirical model accounting for these Nordic conditions was previously developed in Sweden. (2) For other roads with a less pronounced seasonal variation (e.g. in Denmark, Germany, Austria) methods using a constant emission factor maybe appropriate. Two models are presented here.Further, we apply the different emission models to data sets outside the original countries. For example, we apply the “Swedish” model for two streets without studded tyre usage and the “German” model for Nordic data sets. The “Swedish” empirical model performs best for streets with studded tyre use, but was not able to improve the correlation versus measurements in comparison to using constant emission factors for the Danish side. The “German” method performed well for the streets without clear seasonal variation and reproduces the summer conditions for streets with pronounced seasonal variation. However, the seasonal variation of PM emission factors can be important even for countries not using studded tyres, e.g. in areas with cold weather and snow events using sand and de-icing materials. Here a constant emission factor probably will under-estimate the 90-percentiles and therefore a time varying emission model need to be used or developed for such areas.All emission factor models consistently indicate that a large part (about 50–85% depending on the location) of the total PM10 emissions originates from non-exhaust emissions. This implies that reduction measures for the exhaust part of the vehicle emissions will only have a limited effect on ambient PM10 levels.  相似文献   
184.
Despite broad recognition of the value of social sciences and increasingly vocal calls for better engagement with the human element of conservation, the conservation social sciences remain misunderstood and underutilized in practice. The conservation social sciences can provide unique and important contributions to society's understanding of the relationships between humans and nature and to improving conservation practice and outcomes. There are 4 barriers—ideological, institutional, knowledge, and capacity—to meaningful integration of the social sciences into conservation. We provide practical guidance on overcoming these barriers to mainstream the social sciences in conservation science, practice, and policy. Broadly, we recommend fostering knowledge on the scope and contributions of the social sciences to conservation, including social scientists from the inception of interdisciplinary research projects, incorporating social science research and insights during all stages of conservation planning and implementation, building social science capacity at all scales in conservation organizations and agencies, and promoting engagement with the social sciences in and through global conservation policy‐influencing organizations. Conservation social scientists, too, need to be willing to engage with natural science knowledge and to communicate insights and recommendations clearly. We urge the conservation community to move beyond superficial engagement with the conservation social sciences. A more inclusive and integrative conservation science—one that includes the natural and social sciences—will enable more ecologically effective and socially just conservation. Better collaboration among social scientists, natural scientists, practitioners, and policy makers will facilitate a renewed and more robust conservation. Mainstreaming the conservation social sciences will facilitate the uptake of the full range of insights and contributions from these fields into conservation policy and practice.  相似文献   
185.
Meeting the manifold challenges connected to climate change makes high demands on individual competencies. To prepare actors for those challenges learning settings are needed in higher education that are suitable for that goal. A theoretical framework for relevant key competencies can be found in the discourse of Education for Sustainable Development (ESD). In this paper we introduce and discuss two learning settings that employ adapted sustainability science approaches: the syndrome approach and scenario analysis. Both approaches are discussed with reference to their didactic goals to foster the acquisition of the corresponding competencies. The usefulness of these two approaches in creating appropriate learning settings is demonstrated in empirical studies.  相似文献   
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188.
A comparison of international literature in occupational safety and health (OSH) research over the years from 1980 to 1998 was conducted. The comparison is based on the different languages of the over 35,000 articles, which were collected from different databases. The distribution of languages in the analyzed data has to be considered carefully with respect to the original purpose of the data collection and the specific role of the international publication language, English. The comparison shows that in several aspects OSH research does not differ in different publication languages. In some methodological aspects, and in specific objects of research, differences between articles published in different languages can be found.  相似文献   
189.
Research on helping has identified positive consequences of helping for the helper, beneficiary, group, and organization. Recent research, however, raises concerns about contingencies that influence the outcomes of helping and suggests the need for a more nuanced perspective on the positive outcomes of helping. In this paper, we develop a novel theoretical perspective to address these contingencies by differentiating between proactive helping and reactive helping. Drawing from the two main theoretical frameworks, which have been used as the basis for studying helping—social exchange theory and functional motives theory—we discuss differences in the positive consequences of reactive and proactive helping for helpers, dyads, groups, and organizations. We submit that reactive helping facilitates heedful relationships, such that it creates and perpetuates social exchange norms that benefit others in the group. Conversely, we posit that proactive helping is often based on fulfilling personal needs, such that it benefits the self in terms of reputational benefits, well‐being, favorable self‐evaluations, need satisfaction, and self‐development. We discuss theoretical implications of this framework for future research on the positive consequences of helping. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
190.
Biodegradable (compostable) packaging materials made from biopolymers (BP) are introduced into the market to reduce the amounts of conventional packaging materials and at the same time be recovered by the municipal organic waste collection system. The processing of this organic waste mixed with biopolymers has been tested in a commercial treatment facility. The safe use of the compost produced from these materials was demonstrated in a full-scale agricultural application test.  相似文献   
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