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871.
Urban ecologists have demonstrated that cities are functioning ecosystems. It follows then that species living in these contexts should participate in and experience the same suite of biological processes, including evolution, that have occupied scientists for centuries in more “natural” contexts. In fact, urban ecosystems with myriad novel contexts, pressures, and species rosters provide unprecedentedly potent evolutionary stimuli. Here, we present the case for studying adaptive evolution in urban settings. We then review and synthesize techniques into a coherent approach for studying adaptive evolution in urban settings that combines observations of phenotypic divergence, measurements of fitness benefits of novel genetically based phenotypes, and experimental manipulations of potential drivers of adaptation. We believe that studying evolution in urban contexts can provide insights into fundamental evolutionary biology questions on rate, direction, and repeatability of evolution, and may inform species and ecosystem service conservation efforts.  相似文献   
872.
Three men were killed and four others were injured during a well drill operation on Hobson Well C-10A in the Sea Cliff Oil Field (also known as Rincon Oil Field), in Ventura County, California, United States, on August 10, 1994, as a result of errors made by the work supervisors at the site. The oil field was under management by Vintage Petroleum, Ltd., which was sued for negligence by the families of the deceased and injured. The coroner's autopsy examination concluded that the cause of the deaths was due to the inhalation of the toxic gas carbon monoxide (CO). This gas was assumed to have been released from the firing of high-energy guns (HEGs) using carbon-rich explosive pentaerythritol tetranitrate (PETN) in an oxygen-depleted environment, during a fracking operation by Schlumberger Corporation on Well C-10A. The author of this article was appointed as an expert witness by Schlumberger to evaluate if the coroner's conclusion was correct. A series of chemical analytical analyses were conducted on the vapor phase of samples, in addition to dissolved components in water from Well C-10A and two adjacent wells. Stable isotope analyses were also conducted on hydrogen (H2), methane (CH4), nitrogen (N2), CO, and water (H2O) 3 weeks after the accident, as well as on four additional occasions from September to December 1994. Control test analyses were performed on the products from HEG firings, using the same explosives as those used in the perforation of Well C-10A in control chambers at a Schlumberger facility in Houston, Texas. The conclusion reached was that the dominant products of PETN detonations are H2, CH4, CO, and N2. However, the isotope ratios (D/H and 13C/12C) of methane in the control experiments were different in Well C-10A, following the detonation on August 10, 1994, than those resulting from controlled PETN explosions. The conclusion reached in this study was that the fracking of the well at a depth of around 2,150 ft had increased the permeability of the sediment layers in the Padres Zone at that depth to allow the rapid release of a large quantity of natural gas, primarily CH4, which supersaturated the water in the well. This event caused the formation of a large bubble, which ballooned out of the well to the surface, displacing air in the location where the men were working, and thus causing asphyxiation, which resulted in the death of the three men. The judge accepted this interpretation.  相似文献   
873.
Two industrial sites were investigated based on years of available hydrogeologic information and monitoring data for soil and groundwater. Collected data were forensically evaluated using age-dating and fingerprinting methods. The previous business uses of the project sites were as a gas station, laundry/dry-cleaning service, and car wash with petroleum underground storage tanks (USTs). As a result, these sites were exposed to a number of toxic contaminants at relatively high concentrations. Source control was necessary for successful remediation and the ultimate removal of the remaining compounds from these industrial sites. Although contaminated soil around the source was excavated during the remedial action and the high concentrations of contaminants were reduced, typical groundwater contaminants such as petroleum hydrocarbons as gasoline (TPH-G), benzene, toluene, ethylbenzene, xylenes (BTEX), and oxygenates including methyl tert-butyl ether (MTBE), diisopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), and tert-butyl alcohol (TBA) were persistently found at the studied sites around the source points. The plume and concentration of contaminants had changed their shapes and strength for all monitoring periods. Thus, additional source control seems to be a requirement for the complete removal of source contamination, which must be ascertained with groundwater and soil monitoring on a regular time base. For the study sites, monitored natural attenuation was relatively feasible for the long-term plan; however, it did not offer a perfect remediation solution for an ultimate goal because of residual toxic compounds that might have affected the surrounding residential areas at higher concentrations than their health limits. Therefore, as a remediation strategy, the combination of clean-up technology and natural attenuation with monitoring activities are more highly recommended than either clean-up or natural attenuation used separately.  相似文献   
874.
The ability of near‐surface disposal facility cover designs to meet percolation performance criteria can be influenced by naturally occurring climatic mechanisms as well as anthropogenic forcing. This study was conducted to determine the effect of climate‐induced events on percolation based, probabilistic distributions derived from historical climate data. Water balance predictions were evaluated using the HELP model, employing several variations of degradation in a traditional RCRA disposal facility cover design over a 100‐year simulation period. Results demonstrated that changes in precipitation and temperature can influence performance. The analysis also revealed that when both precipitation and temperature are increased, warmer temperatures tend to offset some of the impact from greater precipitation. ©2015 Wiley Periodicals, Inc.  相似文献   
875.
城市污水生物处理系统中微生物酶的活性及其分布   总被引:1,自引:0,他引:1  
李茵  罗翠  Chr 《环境污染与防治》2007,29(5):333-335
通过水解模式底物进行分光光度测定的方法,研究了城市污水生物处理系统中微生物酶的活性.选取亮氨酸氨基肽酶、β-葡萄糖苷酶、碱性磷酸酶和脂酶等胞外酶进行分析,结果发现4种胞外酶的平均活性在31.O~88.5 μmol/(L·h),其中76.9%~94.8%的酶活性分布在活性污泥中,说明绝大部分胞外酶是与细胞相连或固定在细胞外多聚絮体基质里.混合水样和出水水样中的DOC几乎相等,而各胞外酶与DOC不存在任何显著的相关关系.增加NO3-浓度可提高亮氨酸氨基肽酶和β-葡萄糖苷酶的活性,但对碱性磷酸酶和脂酶却有明显的抑制作用.  相似文献   
876.
Journal of Material Cycles and Waste Management - Leather production is a technology that boosts the economy because of its versatility and durability. However, the wastes generated throughout the...  相似文献   
877.
Journal of Material Cycles and Waste Management - The daily use of facemask to prevent virus transmission increases the negative effect on the environment because of improper waste disposal. Due to...  相似文献   
878.
Journal of Material Cycles and Waste Management - The use of lignocellulosic fibers as fillers in polymer matrices has aroused the interest of the scientific community and industrial sectors. In...  相似文献   
879.
Journal of Material Cycles and Waste Management - Fused filament fabrication (FFF) based additive manufacturing (AM) process is a widely used and emerging manufacturing process for...  相似文献   
880.
Unprecedented and dramatic transformations are occurring in the Arctic in response to climate change, but academic, public, and political discourse has disproportionately focussed on the most visible and direct aspects of change, including sea ice melt, permafrost thaw, the fate of charismatic megafauna, and the expansion of fisheries. Such narratives disregard the importance of less visible and indirect processes and, in particular, miss the substantive contribution of the shelf seafloor in regulating nutrients and sequestering carbon. Here, we summarise the biogeochemical functioning of the Arctic shelf seafloor before considering how climate change and regional adjustments to human activities may alter its biogeochemical and ecological dynamics, including ecosystem function, carbon burial, or nutrient recycling. We highlight the importance of the Arctic benthic system in mitigating climatic and anthropogenic change and, with a focus on the Barents Sea, offer some observations and our perspectives on future management and policy.  相似文献   
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