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841.
842.
The regulatory environment is assumed to be characterized by changing labor costs and productivity, and by the existence of set-up costs for rate reviews. If the commission behaves myopically, price changes are shown to occur only when a threshold deviation of actual from target return is reached. During periods where productivity (wage) increases predominate, the actual return is thus consistently higher (lower) than the target level. If, however, the commission incorporates dynamic trends into its decision-making process, there are intervals where actual return both exceeds and falls short of target levels; on average, the firm earns over time a return that is approximately equal to the target level. 相似文献
843.
The implications of retirement for marital and family relationships were explored in golden wedding couples, against a background of those few studies that have so far examined relationships in long-married couples. Older couples can be described in two domains: behavioral and affective. Five activity types are derived from the amount or diversity of shared activities between spouses during a typical day. These types interact with the degree of intimacy measured on two instruments. It was concluded that retirement does not affect intimacy directly, but that it does indirectly through extra time and proximity which provide opportunity for enhancing prevailing intimacy between partners or for magnifying irritations. 相似文献
844.
David L. Wiesenthal Leonard H. Theodor Donna E. Hurford 《Journal of Nonverbal Behavior》1982,7(2):117-120
Undergraduate subjects were seen to accurately discriminate between simulating actors and genuinely disabled males confined to wheelchairs. Judgments were based on skill in manipulating the wheelchair, poorer muscular development of the disabled, and on appearance of clothing. Implications for research on the disabled employing actors was discussed.This study was supported by a grant from the York University Faculty of Arts awarded to the first two authors. The project was performed as the third author's Honours thesis. The authors wish to thank all participants for their cooperation and assistance in making this research possible. The authors also wish to thank Gail Kenyon, Coordinator of the Centre for Handicapped Students who helped recruit participants for the videotaping and to Lucie Cantrell, Executive Officer of the York University Counselling and Development Centre who arranged for the use of the Centre's facilities and equipment. 相似文献
845.
846.
Roy E. Albert Joellen Lewtas Stephen Nesnow Todd W. Thorslund Elizabeth Anderson 《Risk analysis》1983,3(2):101-117
An estimation of the human lung cancer “unit risk” from diesel engine particulate emissions has been made using a comparative potency approach. This approach involves evaluating the tumorigenic and mutagenic potencies of the particulates from four diesel and one gasoline engine in relation to other combustion and pyrolysis products (coke oven, roofing tar, and cigarette smoke) that cause lung cancer in humans. The unit cancer risk is predicated on the linear nonthreshold extrapolation model and is the individual lifetime excess lung cancer risk from continuous exposure to 1 μg carcinogen per m3 inhaled air. The human lung cancer unit risks obtained from the epidemiologic data for coke oven workers, roofing tar applicators, and cigarette smokers were, respectively, 9.3 × 10?4, 3.6 × 10?4, and 2.2 × 10?6 per μg particulate organics per m3 air. The comparative potencies of these three materials and the diesel and gasoline engine exhaust particulates (as organic extracts) were evaluated by in vivo tumorigenicity bioassays involving skin initiation and skin carcinogenicity in SENCAR mice and by the in vitro bioassays that proved suitable for this analysis: Ames Salmonella microsome bioassay, L5178Y mouse lymphoma cell mutagenesis bioassay, and sister chromatid exchange bioassay in Chinese hamster ovary cells. The relative potencies of the coke oven, roofing tar, and cigarette smoke emissions, as determined by the mouse skin initiation assay, were within a factor of 2 of those determined using the epidemiologic data. The relative potencies, from the in vitro bioassays as compared to the human data, were similar for coke oven and roofing tar, but for the cigarette smoke condensate the in vitro tests predicted a higher relative potency. The mouse skin initiation bioassay was used to determine the unit lung cancer risk for the most potent of the diesel emissions. Based on comparisons with coke oven, roofing tar, and cigarette smoke, the unit cancer risk averaged 4.4 × 10?4. The unit lung cancer risks for the other, less potent motor-vehicle emissions were determined from their comparative potencies relative to the most potent diesel using three in vitro bioassays. There was a high correlation between the in vitro and in vivo bioassays in their responses to the engine exhaust particulate extracts. The unit lung cancer risk per μg particulates per m3 for the automotive diesel and gasoline exhaust particulates ranged from 0.20 × 10?4 to 0.60 × 10?4; that for the heavy-duty diesel engine was 0.02 × 10?4. These unit risks provide the basis for a future assessment of human lung cancer risks when combined with human population exposure to automotive emissions. 相似文献
847.
There has been much discussion about the factors underlying inflation in the health care sector and the means to moderate increases in health expenditures. This paper identifies various costcontainment strategies and synthesizes research findings that may be helpful in evaluating their effectiveness. The review demonstrates the complexity of the issues and relationships that must be confronted and understood in cost containment. The delivery system is shown to be not well-suited to improving efficiency and restraining health care expenditure. Any single strategy, whether it involves restructuring the market or more direct regulation, cannot in itself accomplish the combination of expenditure control and adequacy of services that is socially desirable. A number of mutually reinforcing strategies are required. Finally, more empirical and analytical information on incentives, provider and regulatory decisionmaking, costs of regulation, and the dynamics of negotiation, is essential for the design of an effective costcontainment program. 相似文献
848.
849.
This study assessed the playgrounds of developmental day care centers and compared them with playgrounds of regular certified day care centers. Twenty playgrounds, randomly selected from the listing of developmental day centers, were compared with a matched sample of 20 playgrounds from certified day care centers in one state. A revision of Frost's Playground Rating System (1978b) was employed to rate the two groups of playgrounds on content, safety, and function. Data were analyzed using an analysis of variance technique. The quality of developmental day center playgrounds for exceptional children was inferior to that of regular day care center playgrounds in terms of playground content. No significant differences were noted on safety or function. 相似文献
850.
A theory of ethnic antagonism: the split labor market 总被引:9,自引:0,他引:9
E Bonacich 《American sociological review》1972,37(5):547-559