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排序方式: 共有848条查询结果,搜索用时 9 毫秒
841.
Berke EM Ackermann RT Lin EH Diehr PH Maciejewski ML Williams B Patrick MB LoGerfo JP 《Journal of aging and physical activity》2006,14(3):313-324
This study evaluated the effect of distance on the likelihood of initiating and maintaining regular use of a fitness-program benefit in a population of managed Medicare seniors. We studied 8,162 participants and nonparticipants in a managed-care fitness-program benefit: a structured group exercise program or an unstructured health-club membership. Participants in both programs lived significantly closer to facilities than nonparticipants did (structured, p < .001; unstructured, p = .017). Participants living closer to unstructured-program sites attended more frequently than those farther away (p = .008). Distance was not correlated with frequency of use in the structured program (p = .49). Collectively, these analyses demonstrate that distance is related to uptake and, in some cases, continued use of a fitness-program benefit. Health systems providing fitness-program benefits as a way to increase physical activity levels of their plan members should consider location of program facilities in relation to members' home addresses to maximize use of the benefit. 相似文献
842.
Umberson D Williams K Powers DA Liu H Needham B 《Journal of health and social behavior》2006,47(1):1-16
We work from a life course perspective and identify several reasons to expect age and gender differences in the link between marital quality and health. We present growth curve evidence from a national longitudinal survey to show that marital strain accelerates the typical decline in self-rated health that occurs over time and that this adverse effect is greater at older ages. These findings fit with recent theoretical work on cumulative adversity in that marital strain seems to have a cumulative effect on health over time-an effect that produces increasing vulnerability to marital strain with age. Contrary to expectations, marital quality seems to affect the health of men and women in similar ways across the life course. 相似文献
843.
Geoffrey C. Williams Hallgeir Halvari Christopher P. Niemiec Øystein Sørebø Anja H. Olafsen Cathrine Westbye 《Work and stress》2013,27(4):404-419
Somatic symptom burden, or the experience of physical symptomatology without a medical explanation, is related to functional disability and poor quality of life. The consequences of somatic symptom burden extend beyond the individual and affect society, as manifested in higher medical utilization and lower job productivity. Using self-determination theory, we posited that employees' perceptions of managerial support for basic psychological needs may be associated with lower levels of somatic symptom burden among employees, in part because such contexts promote autonomous self-regulation (a type of motivation) at work. Also, we posited that somatic symptom burden among employees would explain some of the relations of managerial need support and autonomous self-regulation at work to indices of work-related functioning, namely emotional exhaustion, turnover intention and absenteeism. Results from 287 Norwegian employees confirmed these hypotheses. These findings not only identify a theoretical mechanism that may explain (in part) the origin of somatic symptoms, but also offer a model by which social-contextual and motivational factors affect important work-related outcomes. These findings also bespeak the importance of developing workplace interventions that provide support for satisfaction of the basic psychological needs. 相似文献
844.
In 1968 the first cohesive theory on goal setting proposed that difficult goals produce higher levels of performance than easy goals and that specific goals produce a higher level of performance than “do your best” goals. While over 40 years of research supports this theory, there has been some discrepancy regarding the use of very difficult goals. This study was designed to examine the effects on performance of different levels of performance improvement goals and two different types of feedback, as feedback is often used in conjunction with goal setting. A group design was used with participants receiving one of two goal levels, and two different types of feedback. While no significant effects were found between the two types of feedback, goal level produced significant results in terms of performance and accuracy. 相似文献
845.
A GPSS/360 model was developed to investigate the behavior of a university's motor pool dispatch fleet. Time-series data were collected and frequency distributions were constructed for vehicle request patterns and trip-duration times. Regression analysis was performed to formulate trip mileage generators as functions of service time. Appropriate statistical goodness-of-fit tests were conducted to ascertain the extent of congruence between actual system behavior and expectations based on a number of theoretical distributions. Analysis of simulated response variables indicates that the model's internal structure reproduces reality to a high degree. Fifteen years of simulated experience were generated for six alternative fleet size configurations; results suggest that reductions in existing fleet capacity could be realized without effecting undue impairment in service levels. 相似文献
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848.
Elliott F. Williams Süleyman Tüfekcli Mehmet Akansel 《Production and Operations Management》1997,6(1):74-96
Lot streaming is the process of splitting a job or lot into sublots to reduce its makespan on a sequence of machines. The goal in the lot streaming problem is to find the optimal size of each sublot that will minimize the makespan. The makespan is defined as the time the last sublot completes its processing on the last machine. If the sizes of these sublots are restricted to remain the same on all machines, the solution is called a consistent sublot solution. However, if the sizes of the sublots are allowed to vary, the solution is referred to as a nonconsistent or variable sublot solution. Also, if the machines must be in operation continuously from the first to the last sublot, the solution is a no idling solution. When setups are explicitly considered in the problem, there will be two cases. If setups on each machine require some portion of the first sublot be present by the machine, the problem is referred to as the attached setup time problem. If setups can be performed ahead of time before the first sublot reaches the particular machine, the corresponding problem is referred to as the detached setup problem. Finally, if the machines are allowed to be idle between the processing of sublots, the resultant solution is an intermittent idling solution. In this paper, the consistent sublot lot streaming problem with intermittent idling and no setups is discussed. The models developed also assume that the number of sublots are fixed and known. The m machine two sublot lot streaming problem is reviewed. An algorithm for the three sublot, m machine problem is derived using a network representation of the problem. The complexity of the algorithm is O (m2). Finally, using the insights from three sublot problem, a heuristic algorithm is provided for the m machine, n sublot problems. The results on the proposed heuristic are very encouraging; average percent deviation from optimal makespan is approximately at 0.76% on 155 randomly generated problems with different m and n values. 相似文献