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301.
Progress towards climate change aware regional sustainable development is affected by actions at multiple spatial scales and governance levels and equally impacts actions at these scales. Many authors and policy practitioners consider therefore that decisions over policy, mitigation strategies and capacity for adaptation to climate change require construction and coordination over multiple levels of governance to arrive at acceptable local, regional and global management strategies. However, how such processes of coordination and decision-aiding can occur and be maintained and improved over time is a major challenge in need of investigation. We take on this challenge by proposing research-supported methods of aiding multi-level decision-making processes in this context. Four example regionally focussed multi-level case studies from diverse socio-political contexts are outlined—estuarine management in Australia’s Lower Hawkesbury, flood and drought management in Bulgaria’s Upper Iskar Basin, climate policy integration in Spain’s Comunidad Valenciana and food security in Bangladesh’s Faridpur District—from which insights are drawn. Our discussion focuses on exploring these insights including: (1) the possible advantages of informal research-supported processes and specifically those that provide individual arenas of participation for different levels of stakeholders; (2) the complexity of organisation processes required for aiding multi-level decision-making processes; and (3) to what extent progress towards integrated regional policies for climate change aware sustainable development can be achieved through research-supported processes. We finish with a speculative section that provides ideas and directions for future research.  相似文献   
302.
Traditional regulatory methods for evaluating air toxics have several limitations. Two common methods rely either on self-reported industrial emissions from the Toxics Release Inventory or a single summary statistic such as the average or arithmetic mean. A novel statistical approach for detecting overall long term improvement in ambient air quality is demonstrated using measurements of the air toxic benzene evaluated over five years in Houston, Texas. Through trends of seven key statistical measures, long term improvements were detected at more monitors than would have been found using traditional methods while lack of improvement is highlighted at other monitors. This new approach includes analysis of high and low end concentrations, as well as central tendency, evaluated at specific air toxic human health risk thresholds.  相似文献   
303.
Open-plan offices are equipped with barriers such as panels and bookshelves to induce the perception of a private workspace. Despite perceived privacy, irrelevant speech contributes to mental workload, poor performance, stress, and fatigue. Certain dispositional variables related to sustained attention might exacerbate the effects of speech-related noise. This study used a 3 × 3 × 2 mixed factor design to determine the effects of two forms of irrelevant speech and individual differences on performance of a real-world verbal task and mental workload. The Expanded Tellegen Absorption Scale (ETAS) based upon Tellegen and Atkinson's scale was used to assess individual differences in focused attention. The NASA Task Load Index was administered to assess mental workload. Main effects of noise were found on performance and mental workload. Irrelevant speech appeared to increase false alarms and completion rates. Workload ratings were higher in the irrelevant speech conditions. Other differences found were among High and Low Task and Imaginative Absorbers, as measured by the ETAS. Recommendations to reduce the impact of irrelevant speech and future research suggestions are provided.  相似文献   
304.
Removal processes for arsenic in constructed wetlands   总被引:2,自引:0,他引:2  
Lizama A K  Fletcher TD  Sun G 《Chemosphere》2011,84(8):1032-1043
Arsenic pollution in aquatic environments is a worldwide concern due to its toxicity and chronic effects on human health. This concern has generated increasing interest in the use of different treatment technologies to remove arsenic from contaminated water. Constructed wetlands are a cost-effective natural system successfully used for removing various pollutants, and they have shown capability for removing arsenic. This paper reviews current understanding of the removal processes for arsenic, discusses implications for treatment wetlands, and identifies critical knowledge gaps and areas worthy of future research. The reactivity of arsenic means that different arsenic species may be found in wetlands, influenced by vegetation, supporting medium and microorganisms. Despite the fact that sorption, precipitation and coprecipitation are the principal processes responsible for the removal of arsenic, bacteria can mediate these processes and can play a significant role under favourable environmental conditions. The most important factors affecting the speciation of arsenic are pH, alkalinity, temperature, dissolved oxygen, the presence of other chemical species - iron, sulphur, phosphate -, a source of carbon, and the wetland substrate. Studies of the microbial communities and the speciation of arsenic in the solid phase using advanced techniques could provide further insights on the removal of arsenic. Limited data and understanding of the interaction of the different processes involved in the removal of arsenic explain the rudimentary guidelines available for the design of wetlands systems.  相似文献   
305.
Becoming proficient at navigation in urban environments is something that we all aspire to. Here we asked whether being an expert at wayfinding in one environment has any effect on learning new spatial layouts. Licensed London taxi drivers are among the most proficient urban navigators, training for many years to find their way around a complex and irregularly-laid out city. We first tested how well they could learn the layout of an unfamiliar town compared with a group of non-taxi drivers. Second, we investigated how effectively taxi drivers could integrate a new district into their existing spatial representation of London. We found that taxi drivers were significantly better than control participants at executing routes through the new town, and representing it at a map-like survey level. However, the benefits of navigational expertise were not universal. Compared with their performance in the new town, taxi drivers were significantly poorer at learning the layout of a new area that had to be integrated with their existing knowledge of London. We consider reasons for this picture of facilitation and limitation, in particular drawing parallels with how knowledge acquisition occurs in the context of expertise in general.  相似文献   
306.
Meierdiercks, Katherine L., James A. Smith, Mary Lynn Baeck, and Andrew J. Miller, 2010. Analyses of Urban Drainage Network Structure and Its Impact on Hydrologic Response. Journal of the American Water Resources Association (JAWRA) 1-12. DOI: 10.1111/j.1752-1688.2010.00465.x Abstract: Urban flood studies have linked the severity of flooding to the percent imperviousness or land use classifications of a watershed, but relatively little attention has been given to the impact of urban drainage networks on hydrologic response. The drainage network, which can include storm pipes, surface channels, street gutters, and stormwater management ponds, is examined in the Dead Run watershed (14.3 km2). Comprehensive digital representations of the urban drainage network in Dead Run were developed and provide a key observational resource for analyses of urban drainage networks and their impact on hydrologic response. Analyses in this study focus on three headwater subbasins with drainage areas ranging from 1.3 to 1.9 km2 and that exhibit striking contrasts in their patterns and history of development. It is shown that the drainage networks of the three subbasins, like natural river networks, exhibit characteristic structures and that these features play critical roles in determining urban hydrologic response. Hydrologic modeling analyses utilize the Environmental Protection Agency’s Stormwater Management Model (SWMM), which provides a flexible platform for examining the impacts of drainage network structure on hydrologic response. Results of SWMM modeling analyses suggest that drainage density and presence of stormwater ponds impact peak discharge more significantly in the Dead Run subbasins than the percent impervious or land use type of the subbasins.  相似文献   
307.
Endocrine disrupting chemicals (EDCs) can alter endocrine function in exposed animals. Such critical effects, combined with the ubiquity of EDCs in sewage effluent and potentially in tapwater, have led to concerns that they could be major physiological disruptors for wildlife and more controversially for humans. Although sewage effluent is known to be a rich source of EDCs, there is as yet no evidence for EDC uptake by invertebrates that live within the sewage treatment system. Here, we describe the use of an extraction method and GC-MS for the first time to determine levels of EDCs (e.g., dibutylphthalate, dioctylphthalate, bisphenol-A and 17beta-estradiol) in tissue samples from earthworms (Eisenia fetida) living in sewage percolating filter beds and garden soil. To the best of our knowledge, this is the first such use of these techniques to determine EDCs in tissue samples in any organism. We found significantly higher concentrations of these chemicals in the animals from sewage percolating filter beds. Our data suggest that earthworms can be used as bioindicators for EDCs in these substrates and that the animals accumulate these compounds to levels well above those reported for waste water. The potential transfer into the terrestrial food chain and effects on wildlife are discussed.  相似文献   
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