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31.
PROBLEM: Young drivers, particularly those who are newly licensed, have a very high crash risk. This paper examines the risk factors underlying their high crash rates and assesses the extent to which existing graduated licensing programs address these risks and whether improvements to these programs should be considered. METHOD: Review and synthesis of the literature. RESULTS: The elevated risk among young drivers of being in an injury crash is the result of a number of factors found alone or in combination, such as risky driving, alcohol use, seat belt nonuse, driver distraction, fatigue, and vehicle choice. Nighttime and passenger restrictions, adopted widely in the United States, work by keeping drivers out of hazardous situations rather than by addressing risk factors directly. However, the risk factors remain in play in driving situations not specifically restricted by law. Although other graduated licensing components adopted around the world-more stringent exit tests (i.e., you need to pass a test to move to the next stage), hazard perception tests, and restrictions on speed, vehicle power, and roadway access-make sense based on the identified risk factors, they are not yet supported by research. Should research findings warrant it, consideration should be given to providing guidance to parents about how to keep their beginning drivers safe, including information on vehicle choice. IMPACT ON RESEARCH, PRACTICE, AND POLICY: Researchers should continue to monitor and to evaluate innovative approaches to reduce the crash risk of young drivers. The effectiveness of new approaches should be established before adoption on a wider scale takes place.  相似文献   
32.
Acid drainage from abandoned mines is a widespread problem in old mining regions. Agencies seeking to abate it face the prospect of dealing with hundreds of potential abatement projects, stretching decades into the future. A systematic regional analysis is necessary to establish locations, objectives, priorities, and phasing of such projects. The U.S. Bureau of Mines developed a novel procedure for abatement planning in the 420 square mile Blacklick Creek Watershed in Pennsylvania. The plan sought to direct abatement projects toward pollution sources where degradation was worst and adverse effects greatest. It established abatement priorities by comparing the “supply” of sources to be reclaimed (the degrees of old mines' water quality degradation) with the “demand” for abatement to be done (the natural and cultural values represented by the region's demography, land use and other non-mining characteristics). Matrices were used to define the relationships among mining and non-mining factors; maps were developed to show the geographic distribution of the conclusions. The locations, priorities, and phasing of abatement objectives shown on the maps should provide guidance for any abatement effort, no matter what type of technology is applied to achieve the objectives. Over the many years in which abatement projects are to be performed in the Watershed, the plan can be used to define, coordinate, and establish priorities for the projects in a manner that can result in maximum abatement benefits from the application of limited funds.  相似文献   
33.
ABSTRACT: The increasing use of irrigation for urban landscapes is causing new demands for efficient watering systems. Conservation techniques for irrigated agricultural fields cannot be applied to urban landscapes without amendment. This paper attempts to review methods of urban landscape water conservation in the context of the diversity and complexity of urban landscapes and the demands upon them for quality of the urban environment. A development's initial site layout and planting design fundamentally determine how much irrigation water will be required; the complexity and creativity inherent in urban design open a number of specific possibilities for reducing water demand. Irrigation hardware is then designed to deliver the required volume of water to the specified landscape efficiently by implementing a number of physical and operational principles. Maintenance of the finished development involves monitoring results and making adjustments as the plantings grow and develop. The potential for conserving urban irrigation water is large. Effective conservation need not compromise other qualities of the urban environment such as aesthetics, screening, or shade. Urban design can address both the kinds of landscapes people need, and minimal consumption of irrigation water.  相似文献   
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Arsenic concentrations of 73 soil samples collected in the semi-arid Zimapán Valley range from 4 to 14 700 mg As kg(-1). Soil arsenic concentrations decrease with distance from mines and tailings and slag heaps and exceed 400 mg kg(-1) only within 500 m of these arsenic sources. Soil arsenic concentrations correlate positively with Cu, Pb, and Zn concentrations, suggesting a strong association with ore minerals known to exist in the region. Some As was associated with Fe and Mn oxyhydroxides, this association is less for contaminated than for uncontaminated samples. Very little As was found in the mobile water-soluble or exchangeable fractions. The soils are not arsenic contaminated at depths greater than 100 cm below the surface. Although much of the arsenic in the soils is associated with relatively immobile solid phases, this represents a long-term source of arsenic to the environment.  相似文献   
36.
This paper deals with the basic considerations of the specifications, detail design, and construction of the baghouse system for the 10-unit Shawnee Steam Plant. Special attention is given to a unique preheating and reheating system for each baghouse prior to boiler startup or for cycling operation, criteria for varying number of compartments online against flow (ACFM) to minimize dewpoint consideration, criteria of air-to-cloth ratio as well as filter material and coating, selection of materials, and construction of a unique raft foundation system—all within a total construction period of 42 months.  相似文献   
37.
The landscape architecture profession is a source of creative thinking and planning which is relatively untapped within the mining industry in the United States of America. The landscape architect has been active in European operations for years as indicated by the four examples presented. The landscape architect can provide an important interface with mine design and engineering and environmental affairs. To initiate this interface within the United States, and increase its effectiveness, six objectives are presented and discussed.  相似文献   
38.
When the boundaries of nations cover the same watershed, who owns the border water? The answer to that question is the premise of this paper. A discussion of international water law is given. Implementing the law is portrayed in an outline for (1) administration, (2) a procedure for data collecting, and (3) a computer system for data processing and determining ownership of water for each country. Special situations are considered, and a conclusion developed. After international law between two countries has been established, determining the ownership of boundary water is both feasible and practical. A computer method is shown whereby this is accomplished. The unique aspect of the method is the fact that cooperation and mutual esteem between individuals of both countries are necessary in order to obtain results.  相似文献   
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杨莉琳  谢志霞  朱向梅  撒旭 《环境科学》2023,44(10):5641-5648
以土壤改良剂对荒芜重盐碱地生物改良和开发利用为研究目标,在华北低平原区滨海荒芜重盐碱地开展了施用生物炭(B)和调理剂(C)种植先锋作物油葵的大田试验.生物炭用量设2个水平(0和1.25 kg ·m-2)调理剂施用量设3个水平,分别为0、0.83和1.66 kg ·m-2,共6个处理.油葵收获后按照每30 cm一层采至90 cm搜集土样.结果表明,施用生物炭提高0~30 cm和60~90 cm土层含盐量,而土壤调理剂则显著降低0~30 cm土壤含盐量.没有发现生物炭或调理剂对土壤pH有显著影响.生物炭处理显著抑制土壤硝化作用,导致0~90 cm土层NO3--N含量显著下降,NH4+-N含量提高,对有机质(SOM)含量没有显著影响.施用土壤调理剂提高0~30 cm土壤SOM含量,调理剂施用量为1.66 kg ·m-2时0~90 cm土层的NO3--N含量显著增加.单施生物炭与调理剂或者二者组合均显著增加0~90 cm土壤NH4+-N含量、有效磷(Olsen-P)含量和有效钾(Kex)含量,但生物炭对这3种养分含量的提升效果更显著,土壤调理剂则在增加0~30 cm土壤有机质和降盐方面更有效.施用高量调理剂促进土壤硝化作用,而施用生物炭恰恰起到硝化抑制剂的作用,因此,将生物炭与土壤调理剂结合施用,是滨海荒芜重盐碱地防止NO3--N淋失、减少环境污染、增肥降盐并保障耐盐先锋作物高肥低盐生长环境的有效措施.  相似文献   
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