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61.
Restoration of unobstructed, free-flowing sections of river can provide considerable environmental and ecological benefits. It removes impediments to aquatic species dispersal and improves flow, sediment and nutrient transport. This, in turn, can serve to improve environmental quality and abundance of native species, not only within the river channel itself, but also within adjacent riparian, floodplain and coastal areas. In support of this effort, a generic optimization model is presented in this paper for prioritizing the removal of problematic structures, which adversely affect aquatic species dispersal and river hydrology. Its purpose is to maximize, subject to a budget, the size of the single largest section of connected river unimpeded by artificial flow and dispersal barriers. The model is designed to improve, in a holistic way, the connectivity and environmental status of a river network. Furthermore, unlike most previous prioritization methods, it is particularly well suited to meet the needs of potamodromous fish species and other resident aquatic organisms, which regularly disperse among different parts of a river network. After presenting an initial mixed integer linear programming formulation of the model, more scalable reformulation and solution techniques are investigated for solving large, realistic-sized instances. Results from a case-study of the Pike River Watershed, located in northeast Wisconsin, USA, demonstrate the computational efficiency of the proposed model as well as highlight some general insights about systematic barrier removal planning.  相似文献   
62.
The poverty of forestry policy: double standards on an uneven playing field   总被引:1,自引:0,他引:1  
Can policies designed to maximize exploitation by elites benefit the people who live in forests? Forestry policy throughout the developing world originates from European “scientific” forestry traditions exported during the colonial period. These policies were implemented by foreign and local elite whose interest was to maximize and extract profit. In spite of reforms since the end of the colonial period, policies on the environment usually remain biased against rural communities. Even when more recent policies are fair, the rural poor face severe biases in implementation. In addition, they must compete on an uneven playing field of ethnic and other social inequities and economic hurdles. This article examines how forestry policy and implementation maintain double standards on this uneven playing field in a manner that permanently excludes the rural poor from the natural wealth around them—producing poverty in the process. Change that would support poverty alleviation for forest-based communities requires a radical rethinking of forest policy so as to counterbalance widespread regressive policies and structural asymmetries.  相似文献   
63.
Globally, 1.3 billion on-road vehicles consume 79 quadrillion BTU of energy, mostly gasoline and diesel fuels, emit 5.7 gigatonnes of CO2, and emit other pollutants to which approximately 200,000 annual premature deaths are attributed. Improved vehicle energy efficiency and emission controls have helped offset growth in vehicle activity. New technologies are diffusing into the vehicle fleet in response to fuel efficiency and emission standards. Empirical assessment of vehicle emissions is challenging because of myriad fuels and technologies, intervehicle variability, multiple emission processes, variability in operating conditions, and varying capabilities of measurement methods. Fuel economy and emissions regulations have been effective in reducing total emissions of key pollutants. Real-world fuel use and emissions are consistent with official values in the United States but not in Europe or countries that adopt European standards. Portable emission measurements systems, which uncovered a recent emissions cheating scandal, have a key role in regulatory programs to ensure conformity between “real driving emissions” and emission standards. The global vehicle fleet will experience tremendous growth, especially in Asia. Although existing data and modeling tools are useful, they are often based on convenience samples, small sample sizes, large variability, and unquantified uncertainty. Vehicles emit precursors to several important secondary pollutants, including ozone and secondary organic aerosols, which requires a multipollutant emissions and air quality management strategy. Gasoline and diesel are likely to persist as key energy sources to mid-century. Adoption of electric vehicles is not a panacea with regard to greenhouse gas emissions unless coupled with policies to change the power generation mix. Depending on how they are actually implemented and used, autonomous vehicles could lead to very large reductions or increases in energy consumption. Numerous other trends are addressed with regard to technology, emissions controls, vehicle operations, emission measurements, impacts on exposure, and impacts on public health.

Implications: Without specific policies to the contrary, fossil fuels are likely to continue to be the major source of on-road vehicle energy consumption. Fuel economy and emission standards are generally effective in achieving reductions per unit of vehicle activity. However, the number of vehicles and miles traveled will increase. Total energy use and emissions depend on factors such as fuels, technologies, land use, demographics, economics, road design, vehicle operation, societal values, and others that affect demand for transportation, mode choice, energy use, and emissions. Thus, there are many opportunities to influence future trends in vehicle energy use and emissions.  相似文献   

64.
Excessive phosphorus loading to inland freshwater lakes around the globe has resulted in nuisance plant growth along the waterfronts, degraded habitat for cold-water fisheries, and impaired beaches, marinas, and waterfront property. The direct atmospheric deposition of phosphorus can be a significant contributing source to inland lakes. The atmospheric deposition monitoring program for Lake Simcoe, Ontario, indicates roughly 20% of the annual total phosphorus load (2010–2014 period) is due to direct atmospheric deposition (both wet and dry deposition) on the lake. This novel study presents a first-time application of the genetic algorithm (GA) methodology to optimize the application of best management practices (BMPs) related to agriculture and mobile sources to achieve atmospheric phosphorus reduction targets and restore the ecological health of the lake. The novel methodology takes into account the spatial distribution of the emission sources in the airshed, the complex atmospheric long-range transport and deposition processes, cost and efficiency of the popular management practices, and social constraints related to the adoption of BMPs. The optimization scenarios suggest that the optimal overall capital investment of approximately $2M, $4M, and $10M annually can achieve roughly 3, 4, and 5 tonnes reduction in atmospheric P load to the lake, respectively. The exponential trend indicates diminishing returns for the investment beyond roughly $3M per year and that focusing much of this investment in the upwind, nearshore area will significantly impact deposition to the lake. The optimization is based on a combination of the lowest cost, most beneficial and socially acceptable management practices that develops a science-informed promotion of implementation/BMP adoption strategy. The geospatial aspect to the optimization (i.e., proximity and location with respect to the lake) will help land managers to encourage the use of these targeted best practices in areas that will most benefit from the phosphorus reduction approach.

Implications: Excessive phosphorus loading to inland freshwater lakes around the globe has resulted in nuisance plant growth along the waterfronts, degraded habitat for cold water fisheries, and impaired beaches, marinas and waterfront property. This novel study presents a first-time application of the Genetic Algorithm methodology to optimize the application of best management practices related to agriculture and mobile sources to achieve atmospheric phosphorus reduction targets and restore the ecological health of the lake. The novel methodology takes into account the spatial distribution of the emission sources in the airshed, the complex atmospheric long-range transport and deposition processes, cost and efficiency of the popular management practices and social constraints related to the adoption of BMPs.  相似文献   

65.
Economic theory provides different perspectives on the relationship between environmental regulation and company environmental and competitive performance. A frequently analysed issue refers to the impact of environmental regulation on company performance. Using qualitative data collected within the recently completed Environmental regulation and Market forces Providing Incentives for Resource Efficiency (EMPIRE) project, we analysed the relationship between environmental regulation and company competitiveness, operating in the building and construction (B&C) sector. Empirical evidence from the correlation analysis emphasises that environmental regulation can be an important driver of competitive performance improvements in relevant segments of the European B&C sector.  相似文献   
66.
Nonparametric mean estimation using partially ordered sets   总被引:2,自引:0,他引:2  
In ranked-set sampling (RSS), the ranker must give a complete ranking of the units in each set. In this paper, we consider a modification of RSS that allows the ranker to declare ties. Our sampling method is simply to break the ties at random so that we obtain a standard ranked-set sample, but also to record the tie structure for use in estimation. We propose several different nonparametric mean estimators that incorporate the tie information, and we show that the best of these estimators is substantially more efficient than estimators that ignore the ties. As part of our comparison of estimators, we develop new results about models for ties in rankings. We also show that there are settings where, to achieve more efficient estimation, ties should be declared not just when the ranker is actually unsure about how units rank, but also when the ranker is sure about the ranking, but believes that the units are close.  相似文献   
67.
68.
ABSTRACT

Protected areas are widely recognized as an important strategy for biodiversity conservation. Most of the sites are, however, poorly managed as resource exploitation by fringe communities and low government funding, among other things, threaten their management effectiveness. We used the World Commission on Protected Areas framework for designing management effectiveness evaluation systems, with the Rapid Assessment and Prioritization of Protected Areas Management (RAPPAM) methodology as a tool, to evaluate six components of the management cycle at six sites in Ghana for their management effectiveness. We examined the robustness of RAPPAM as an evaluation tool in the African context. The results showed that most of the sites evaluated are vulnerable and exposed to various degrees of pressure and threats, including poverty in the nearby communities, adjacent land-use and encroachment. On RAPPAM, we noted that apart from inconsistencies in some of the assessment scores due to the biases associated with the self-assessment approach of the methodology, the management effectiveness framework places little emphasis on financing and community participation, though both play major roles in the management process. We proposed a modification of the framework within the African context, to address effectively the underlying courses of pressure and threats facing Ghana’s protected areas.  相似文献   
69.
Norway spruce seedlings colonized with Hebeloma crustuliniforme were grown in growth pouches. After formation of ectomycorrhizas, the seedlings were exposed to Al or the heavy metals Cd, Cu, Ni, or Zn at various concentrations for 5 weeks to estimate the detection limits of metals with X-ray microanalysis in the cryo-scanning electron microscope. When the lowest metal concentrations (1 mM Al(3+), 0.1 mM Cd(2+), 0.2 mM Cu(2+), 0.5 mM Ni(2+), 2 mM Zn(2+)) were applied, only Al and Zn were detected at low X-ray counts in the ectomycorrhizas. After application of 10-fold higher metal concentrations, distinct metal accumulation patterns were observed. Cd was detected predominantly in the Hartig net, Al and Ni in the Hartig net and in the cell walls of the cortex, and Zn in the Hartig net, the cortical cell walls and the fungal mantle. Cu was not detected at all. By combining X-ray microanalysis with absolute metal concentrations found in the roots, the estimated detection limits of X-ray microanalysis were: Al> or =0.86 mg g(-1), Cd> or =0.26 mg g(-1), Ni> or =1.30 mg g(-1), and Zn> or =0.54 mg g(-1), whereas Cu was not detectable even at root concentrations of 0.47 mg g(-1). Treatments with the highest metal concentrations showed high X-ray counts of metals in cells of the stele but reduced concentrations of the macronutrients K, Mg, and P in roots, indicating a possible disturbance of root and ectomycorrhizal function.  相似文献   
70.

Background

There is little available data on chemical use patterns by companies, with few federal requirements for reporting. This results in difficulties for targeting toxics for possible substitution, assisting employers with complying with newer international regulations, and decreased ability to estimate health and environmental impacts.

Methods

Massachusetts chemical use data for manufacturers required under the Toxics Use Reduction Act (TURA) was acquired, with corresponding information on industrial sector classification and employment levels by sector for both Massachusetts (MA) and Connecticut (CT). The MA chemical data was adjusted based on the ratio of employment levels by sector for CT compared to MA to give estimates of chemical usage by sector in CT.

Results

It was estimated that there was over 660 million pounds of chemicals used in CT, with over 300 million pounds each of carcinogens and reproductive hazards (categories overlap). The most common chemicals estimated to be used were styrene monomer (266 million lbs.), sodium hydroxide (60 million lbs.), and methanol (50 million lbs.). The industrial sub-sectors estimated with the highest chemical usage were chemical manufacturing, plastics and rubber products manufacturing, and fabricated metal product manufacturing.

Conclusion

There is extensive chemical use in CT manufacturing, but little direct information on actual use patterns.  相似文献   
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