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891.
Previous attempts to sustain the automobile driving skills of older adults have centered on modifying the driving environment, improving the design of the vehicle, or introducing comprehensive educational programs. This research represents the first experimental investigation of the effects of a physical fitness training program on the automobile driving performance of older adults. Thirty-two older adults were assigned randomly, stratified by gender, to either an experimental group who participated in an 8 week range-of-motion exercise training program or a control group. A 2 (Experimental group/Control group) × 3 (Testing Session) repeated measures experimental design was used to examine the effects of the 8 week range-of-motion exercise training program on subject range of motion and a field-based assessment of automobile driving skill. The results indicated that the program was successful in improving subject shoulder flexibility and trunk rotation, as well as improving scores on the driving skill measure of observing. 相似文献
892.
893.
How integrated is river basin management? 总被引:2,自引:0,他引:2
Land and water management is increasingly focused upon the drainage basin. Thirty-six terms recently used for schemes of “integrated
basin management” include reference to the subject or area and to the aims of integrated river basin management, often without
allusion to the multiobjective nature. Diversity in usage of terms has occurred because of the involvement of different disciplines,
of the increasing coherence of the drainage basin approach, and the problems posed in particular parts of the world. The components
included in 21 different approaches are analyzed, and, in addition to showing that components related broadly to water supply,
river channel, land, and leisure aspects, it is concluded that there are essentially five interrelated facets of integrated
basin management that involved water, channel, land, ecology, and human activity. Two aspects not fully included in many previous
schemes concern river channel changes and the dynamic integrity of the fluvial system. To clarify the terminology used, it
is suggested that the termcomprehensive river basin management should be used where a wide range of components is involved, whereasintegrated basin management can signify the interactions of components and the dominance of certain components in the particular area.Holistic river basin management is advocated as a term representing an approach that is both fully comprehensive and integrated but also embraces the energetics
of the river system and consideration of changes of river channels and of human impacts throughout the river system. The paradigm
of working with the river can be extended to one of working with the river in the holistic basin context. 相似文献
894.
895.
896.
The operation policy for a single reservoir is applied to a rain water cistern system because the functions of a cistern are similar to a simple single reservoir. Since the cistern is a closed system, water loss is negligible. In this study, a dynamic programming analysis has been made to study the effects of the probable weekly rainfall and the water storage in the cistern towards the water consumption policy. The result of this study indicates that the water consumption rate should be adjusted into a lower rate when the water storage in the cistern is low and/or when the expected probable weekly rainfall is low if the owner of the cistern does not want to risk the chance of an empty cistern. The demand for a reliable method for forecasting weekly rainfall is evident in this study. 相似文献
897.
Arnold L. O'Brien Ward S. Motts 《Journal of the American Water Resources Association》1980,16(5):785-789
ABSTRACT: Wetlands occur in a variety of geologic, hydrologic, and topographic settings and exhibit diverse hydrogeologic characteristics. A wetland is more than an organic mat - it is an element in a larger hydrogeologic system. Three distinct but related effects of wetlands are: modifying the character of runoff from a basin, influencing the discharge/recharge relationship with the underlying aquifer, and effecting the potential for ground water development in a wetland dominated basin. An important goal of wetland research is to define the diverse roles that wetlands play in the regional hydrology and to define the geologic, hydrologic, and topographic factors that will allow meaningful distinctions among wetlands. Geologic and hydrologic factors include character and thickness of surficial materials; bedrock type; hydrologic position; permeability of organic layer; transmissivity, quality, and hydrologic connection of wetland related aquifers; ground water outflow; and depth of standing water. Topographic factors are position in the drainage basin, relative size, and absolute size of wetlands. A wetland classification to aid hydrologists and land use planners is proposed using selected factors involving hydrologic position, topographic position, and geologic type. 相似文献
898.
ABSTRACT: The selection of sampling frequencies in order to achieve reasonably small and uniform confidence interval widths about annual sample means or sample geometric means of water quality constituents is suggested as a rational approach to regulatory monitoring network design. Methods are presented for predicting confidence interval widths at specified sampling frequencies while considering both seasonal variation and serial correlation of the quality time series. Deterministic annual cycles are isolated and serial dependence structures of the autoregressive, moving average type are identified through time series analysis of historic water quality records. The methods are applied to records for five quality constituents from a nine-station network in Illinois. Confidence interval widths about annual geometric means are computed over a range of sampling frequencies appropriate in regulatory monitoring. Results are compared with those obtained when a less rigorous approach, ignoring seasonal variation and serial correlation, is used. For a monthly sampling frequency the error created by ignoring both seasonal variation and serial correlation is approximately 8 percent. Finally, a simpler technique for evaluating serial correlation effects based on the assumption of AR(1) type dependence is examined. It is suggested that values of the parameter p1, in the AR(1) model should range from 0.75 to 0.90 for the constituents and region studied. 相似文献
899.
DUNCAN AP 《Environmental management》1999,23(4):495-505
/ Source reduction is recognized as the preferred form of waste management, but its definition is ambiguous. This study proposes four underlying dimensions of the source reduction concept. Source reduction is foremost a preventive activity that reduces the number or extent of environmental impacts. Second, source reduction can prevent both resource consumption and pollution generation impacts. Third, source reduction may be viewed as both a producer and consumer activity. Lastly, it may include frugal and more efficient activities. In surveys exploring these fourdimensions, Polish and American university students evaluated whether 20 activities were examples of source reduction. The American students gave higher ratings to preventive activities over adaptive activities. The Polish students most prominently rated efficient over frugal activities. Factor analysis indicated that both samples identified a group of consumer-based resource conservation activities, with the American students recognizing a cluster of recycling activities. In a separate ranking of environmental protection priorities, the Polish students endorsed pollution prevention, whereas the American students favored both efficient and frugal resource conservation. These findings suggest that the conceptualization of source reduction varies according to contextual factors and that prevention is still an obscure environmental management theme. KEY WORDS: Source reduction; Pollution prevention; Resource conservation; Frugality; Poland 相似文献
900.
Andrew Porteous 《Resources Policy》1975,1(5):284-294
Any recycled material for re-use must be competitive in both quality and cost when compared with virgin raw materials. In the case of domestic refuse these two constraints mean that direct recycling for materials re-use is very restricted and indirect uses are sought instead. One major area of indirect recycling is energy recovery. This paper presents economic analyses performed on a net energy output basis for incineration for both heat and electrical energy production and also for gas production by pyrolysis. Acid hydrolysis of refuse for the production of ethyl alcohol or protein is also presented and analysed in detail since by this means finite oil reserves are conserved. An economic case is made for further work in this area as it is shown to be the only refuse recycling process with the potential to accomplish both refuse disposal and energy recovery at costs substantially less than straight incineration. 相似文献