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51.
Environmental and economic damages caused by agricultural nonpoint source inputs of sediment and associated pollutants are examined. Widespread water quality problems are identified in lakes, rivers, and estuaries in agricultural areas, and billions of dollars of on-site and offsite costs result from this eroded soil every year. Some water bodies have been irretrievably damaged, and expensive rehabilitation programs are needed to remedy in-place water pollution problems if Clean Water Act goals are to be achieved. Unless effective abatement and rehabilitation programs are established, billions of dollars of benefits to future generations will not be realized as more waters become irretrievably damaged, and billions more will continue to be spent by government to treat symptoms of these sediment-related problems.  相似文献   
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Source apportionment of fine particles (PM2.5, particulate matter < 2 microm in aerodynamic diameter) is important to identify the source categories that are responsible for the concentrations observed at a particular receptor. Although receptor models have been used to do source apportionment, they do not fully take into account the chemical reactions (including photochemical reactions) involved in the formation of secondary fine particles. Secondary fine particles are formed from photochemical and other reactions involving precursor gases, such as sulfur dioxide, oxides of nitrogen, ammonia, and volatile organic compounds. This paper presents the results of modeling work aimed at developing a source apportionment of primary and secondary PM2.5. On-road mobile source and point source inventories for the state of Tennessee were estimated and compiled. The national emissions inventory for the year 1999 was used for the other states. U.S. Environmental Protection Agency Models3/Community Multi-Scale Air Quality modeling system was used for the photochemical/secondary particulate matter modeling. The modeling domain consisted of a nested 36-12-4-km domain. The 4-km domain covered the entire state of Tennessee. The episode chosen for the modeling runs was August 29 to September 9, 1999. This paper presents the approach used and the results from the modeling and attempts to quantify the contribution of major source categories, such as the on-road mobile sources (including the fugitive dust component) and coal-fired power plants, to observed PM2.5 concentrations in Tennessee. The results of this work will be helpful in policy issues targeted at designing control strategies to meet the PM2.5 National Ambient Air Quality Standards in Tennessee.  相似文献   
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This article presents a comprehensive managerial model for a sustainable university created by D.Sc. L. Velazquez with empirical data collected from about 80 higher education institutions around the world. The sustainable university model offers a clear perspective about how people responsible for sustainability initiatives achieve their initial momentum to progress to advanced steps in the process to become a sustainable university.This model depicts a structured framework that is comprised of four phases in a strategic management process. In these phases, four diverging strategies, and many practices undertaken by key players of sustainability initiatives in higher education institutions are analyzed.  相似文献   
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Summary A population of a desert spider species (Agelenopsis aperta) that is located in an unusually favorable thermal and feeding environment (AZ riparian), fails to exhibit territorial, foraging and antipredatory behaviors that are appropriate to its environment. Study of the behavior of this spider species is extended to another population that occupies a similar environment but where there is not potential gene flow from individuals occupying more arid habitats (TX riparian). The two populations are shown to experience similar prey availabilities and predation pressures when compared to a third more arid population (NM desert grassland). Analyses of the relevant behavior patterns demonstrate that the TX riparian population is well-adjusted to the ameliorated conditions. Thus, phylogenetic constraints do not appear to underlie the observed maladaptive behavior of the AZ riparian population and credibility is given to potential gene flow influences.  相似文献   
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The field of engineering is changing rapidly as the growing global population puts added demands on the earth's resources: engineering decisions must now account for limitations in materials and energy as well as the need to reduce discharges of wastes. This means educators must revise courses and curricula so engineering graduates are prepared for the new challenges as practicing engineers. The Center for Sustainable Engineering has been established to help faculty members accommodate such changes through workshops and new educational materials, including a free access website with peer-reviewed materials.  相似文献   
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In October 2008, the 5th Environmental Management for Sustainable Universities (EMSU) international conference was held in Barcelona, Spain. It dealt with the need to rethink how our higher educational institutions are facing sustainability. This special issue has been primarily derived from contributions to that conference. This issue builds upon related academic international publications, which have analysed how to use the critical position of universities to accelerate their pace of working to help to make the transition to truly SUSTAINABLE SOCIETIES!This issue focus is on the ‘softer’ issues, such as changes in values, attitudes, motivations, as well as in curricula, societal interactions and assessments of the impacts of research. Insights derived from the interplay of the ‘softer’ issues with the ‘harder’ issues are empowering academic leaders to effectively use leverage points to make changes in operations, courses, curricula, and research. Those changes are being designed to help their students and faculty build resilient and sustainable societies within the context of climate change, the Decade of Education for Sustainable Development (DESD), and the UN Millennium Development Goals (MDGs).The overall systems approach presented by Stephens and Graham provides a structured framework to systematize change for sustainability in higher education, by stressing on the one hand the need for “learning to learn” and on the other hand by integrating leadership and cultural aspects. The “niche” level they propose for innovative interactions between practitioners such as EMSU is exemplary developed by all of the other documents in this special issue. To highlight some of the key elements of the articles in this issue, there are proposals for new educational methods based in sustainability science, a set of inspirational criteria for SD research activities, new course ranking and assessment methods and results of psychological studies that provide evidence that participatory approaches are the most effective way to change values within university members in order to facilitate the development and sharing of new sustainability norms.  相似文献   
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Introduction: Fatal crashes that include at least one fatality of an occupant within 30 days of the crash cause large numbers of injured persons and property losses, especially when a truck is involved. Method: To better understand the underlying effects of truck-driver-related characteristics in fatal crashes, a five-year (from 2012 to 2016) dataset from the Fatality Analysis Reporting System (FARS) was used for analysis. Based on demographic attributes, driving violation behavior, crash histories, and conviction records of truck drivers, a latent class clustering analysis was applied to classify truck drivers into three groups, namely, ‘‘middle-aged and elderly drivers with low risk of driving violations and high historical crash records,” ‘‘drivers with high risk of driving violations and high historical crash records,” and ‘‘middle-aged drivers with no driving violations and conviction records.” Next, equivalent fatalities were used to scale fatal crash severities into three levels. Subsequently, a partial proportional odds (PPO) model for each driver group was developed to identify the risk factors associated with the crash severity. Results' Conclusions: The model estimation results showed that the risk factors, as well as their impacts on different driver groups, were different. Adverse weather conditions, rural areas, curved alignments, tractor-trailer units, heavier weights and various collision manners were significantly associated with the crash severities in all driver groups, whereas driving violation behaviors such as driving under the influence of alcohol or drugs, fatigue, or carelessness were significantly associated with the high-risk group only, and fewer risk factors and minor marginal effects were identified for the low-risk groups. Practical Applications: Corresponding countermeasures for specific truck driver groups are proposed. And drivers with high risk of driving violations and high historical crash records should be more concerned.  相似文献   
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