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971.
Regional monitoring of heavy metal pollution   总被引:1,自引:0,他引:1  
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972.
An airborne gamma-survey provided information about the extent of radioactive contamination around the historic Sleisbeck mine. Quickbird satellite data were acquired to relate airborne measurements to land cover features. Enhanced equivalent uranium (eU) levels were found to be confined to the mine and low grade waste rock dumps. The average terrestrial background radiation dose rate estimated from the airborne gamma survey data was 0.10-0.14 microGy h(-1) while the area around the mine exhibited a maximum of approximately 2.3 microGy h(-1), but measurements on the ground indicate that this maximum is exceeded in some localized areas. Rehabilitation of the site is likely to result in a threefold reduction in radiation doses to people accessing the area.  相似文献   
973.
Although the assessment of circulatory levels of retinoids has become a widely used biomarker of exposure to environmental pollutants, the adverse effects caused by imbalance of the retinoid metabolism and signaling in wildlife are not known in detail. Retinoids play an important role in controlling such vital processes as morphogenesis, development, reproduction or apoptosis. Unlike other signaling molecules, retinoids are not strictly endogenous but they are derived from dietary sources of vitamin A or its precursors and thus they are sometimes referred to as 'dietary' hormones. Some environmental pollutants that affect embryogenesis, immunity or epithelial functions were also shown to interfere with retinoid metabolism and signaling in animals. This suggests that at least some of their toxic effects may be related to interaction with the retinoid metabolism, transport or signal transduction. This review summarizes in vivo and in vitro studies on interaction of environmental complex samples, pesticides, polychlorinated dioxins, polychlorinated biphenyls, polycyclic aromatic compounds and other organic pollutants with physiology of retinoids. It sums up contemporary knowledge about levels of interaction and mechanisms of action of the environmental contaminants.  相似文献   
974.
Animals that guide directions of their locomotion or their migration routes by the lines of the geomagnetic field use either polarity or inclination compasses to determine the field polarity (the north or south direction). Distinguishing the two compass types is a guideline for estimation of the molecular principle of reception and has been achieved for a number of animal groups, with the exception of insects. A standard diagnostic method to distinguish a compass type is based on reversing the vertical component of the geomagnetic field, which leads to the opposite reactions of animals with two different compass types. In the present study, adults of the mealworm beetle Tenebrio molitor were tested by means of a two-step laboratory test of magnetoreception. Beetles that were initially trained to memorize the magnetic position of the light source preferred, during the subsequent test, this same direction, pursuant geomagnetic cues only. In the following step, the vertical component was reversed between the training and the test. The beetles significantly turned their preferred direction by 180 degrees. Our results brought until then unknown original findings that insects, represented here by the T. molitor species, use-in contrast to another previously researched Arthropod, spiny lobster-the inclination compass.  相似文献   
975.
A fundamental question in sympatric speciation is how trophic divergence is achieved. We used an extremely young (<8,000 years) species flock of pupfish (Cyprinodon spp.) from Laguna Chichancanab in south-eastern Mexico to examine divergent evolution of preferences for different feeding substrates. In a test aquarium, we presented four feeding substrates (sand, gravel, a plastic plant, and blank bottom), but no actual food was offered. The four feeding substrates were chosen to mirror the most common substrate types in Laguna Chichancanab. Previous studies demonstrated that benthic food items prevail in the diet of most Cyprinodon species. C. beltrani preferred sand, whereas C. labiosus preferred gravel. F1 hybrids of both species showed intermediate preferences. C. maya searched for food equally at all substrates. As the test fish were reared under identical laboratory conditions (i.e., in the absence of feeding substrates), the species-specific preferences appear to be genetically fixed, suggesting rapid divergent evolution of feeding behaviors.  相似文献   
976.
Environment, Development and Sustainability - Our aim is to determine the factors influencing a visitor’s decision to stay in a green accommodation facility. Visitors from six tourist sites...  相似文献   
977.
Risk perceptions and attitudes toward animals often explain tolerance for wildlife and management preferences. However, little is understood about how these relationships vary across different geographic regions and stakeholder groups. To address this gap in knowledge, we compared differences in acceptance capacity, risk perceptions, perceived enjoyment from outdoor cats, and experiences with outdoor cats among 3 groups (general public, conservation community, and animal‐welfare community) in Hawaii and Florida, two states with large conservation challenges. We combined independently collected data from Florida and Hawaii, to determine how perception of the risks presented by outdoor cats, group membership, and state of residence influenced people's tolerance for outdoor cats. Florida respondents were significantly more tolerant of outdoor cats and less concerned about cat‐related risks than Hawaii respondents (p < 0.05). In both states, animal‐welfare group members reported greater enjoyment seeing cats and perceived a smaller increase in the cat population and lower levels of risk than other groups (p < 0.05). All groups exhibited similar relationships between acceptance capacity and enjoyment and the perceived increase in the cat population. Our results suggest public tolerance for cats varied due to the influence of local or geographical concerns, but that strongly held beliefs, risk perceptions, and feelings about cats explained more of the variance in stakeholder tolerance.  相似文献   
978.
本实验利用标准短期(48- 96 h)实验室测试测定了包括初级生产者,底栖无脊椎动物,水蚤类动物,软体动物和鱼类在内的15种水生生物对于MON 0818的敏感性。MON 0818是一种商业表面活性剂,由多种聚氧乙烯牛脂胺混合而成。此外本实验使用模糊网纹蚤(Ceriodaphnia dubia)潜在的长期(8 d)毒性,确定了暴露浓度。长期毒性测试中未在任何终端指标中发现显著效果。利用得出的数据和文献记载得到物种敏感度在4种暴露条件下的分布,通过对比物种敏感度分布进行了tier-1危害评估。评估显示在本研究规划下(以综述为原型,研究林业除草剂;12 L标准每公顷,等于4.27 kg每公顷) 最差的情况(无意中以最大标签使用速率直接过量喷洒到15 cm深的水体中)会造成中等危害(43.1%的物种处于暴露中,高于中位有效浓度水平)。在更多以最大使用速率使用的典型情况下,受到损害的物种降至20.9%(6 L标准每公顷,相当于2.14 kg每公顷),在更频繁的雇佣施用速率(2.5 L标准每公顷,相当于0.89 kg每公顷)下,受损物种比例降至6.9%。通过草甘膦在环境中的最大测定浓度计算得到MON 0818的浓度,最终受损物种比例(3.8%)则小于此浓度下受损物种比例(5%)。
精选自Jose L. Rodriguez-Gil, Ryan Prosser, David Poirier, Linda Lissemore, Dean Thompson, Mark Hanson, Keith R. Solomon. Aquatic hazard assessment of MON 0818, a commercial mixture of alkylamine ethoxylates commonly used in glyphosate-containing herbicide formulations. Part 1: Species sensitivity distribution from laboratory acute exposures. Environmental Toxicology and Chemistry: Volume 36, Issue 2, pages 501–511, July 2017. DOI: 10.1002/etc.3559
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3559/full
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979.
Citizen science has been gaining momentum in the United States and Europe, where citizens are literate and often interested in science. However, in developing countries, which have a dire need for environmental data, such programs are slow to emerge, despite the large and untapped human resources in close proximity to areas of high biodiversity and poorly known floras and faunas. Thus, we propose that the parataxonomist and paraecologist approach, which originates from citizen‐based science, is well suited to rural areas in developing countries. Being a paraecologist or a parataxonomist is a vocation and entails full‐time employment underpinned by extensive training, whereas citizen science involves the temporary engagement of volunteers. Both approaches have their merits depending on the context and objectives of the research. We examined 4 ongoing paraecologist or parataxonomist programs in Costa Rica, India, Papua New Guinea, and southern Africa and compared their origins, long‐term objectives, implementation strategies, activities, key challenges, achievements, and implications for resident communities. The programs supported ongoing research on biodiversity assessment, monitoring, and management, and participants engaged in non‐academic capacity development in these fields. The programs in Southern Africa related to specific projects, whereas the programs in Costa Rica, India, and Papua New Guinea were designed for the long term, provided sufficient funding was available. The main focus of the paraecologists’ and parataxonomists’ activities ranged from collection and processing of specimens (Costa Rica and Papua New Guinea) or of socioeconomic and natural science data (India and Southern Africa) to communication between scientists and residents (India and Southern Africa). As members of both the local land user and research communities, paraecologists and parataxonomists can greatly improve the flow of biodiversity information to all users, from local stakeholders to international academia.  相似文献   
980.

Watershed processes and their effects on coasts are shaped by numerous interacting natural and societal factors. The knowledge of these factors and processes is often limited. This makes the field prone to politicisations with debates, research, and interventions being confined to a few selected factors. Debates on the causes of high river sediment loads and coastal sedimentation in Java have focussed on rainfed agriculture on peasants’ private lands, while other drivers have been neglected. This has undermined the effectiveness of watershed management. This paper links the sedimentation of the Segara Anakan lagoon on Java’s south coast with landscape characteristics and transformations in its catchment. Three-fourths of the lagoon have silted up since 1857/60. This is the result of a much broader range of drivers than commonly assumed to date. In addition to rainfed agriculture on peasants’ private lands, these drivers include coffee cultivation, timber extraction, plantation development, and in-migration in the late nineteenth and early twentieth century; erosion on contested state forest and plantation lands; state forest management practices; slope cuts to enlarge agricultural fields; agriculture in riparian zones; erosion from roads, trails, and settlements; river channel and floodplain modifications; and volcanic eruptions. The choice and expectations of societal responses aimed at reducing river sediment loads and coastal sedimentation hence need to be reconsidered, and related debates and research agendas must be broadened.

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