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Abstract

Nineteen college men and women (aged 18–23 yrs, × = 21.1) were studied to ascertain the force-time components of a rapid maximal voluntary isometric contraction (MVC) for ankle dorsiflexors, knee extensors, elbow flexors, wrist flexors and hand grip. Standardized isometric strength testing protocol was used. After a practice period subjects were instructed to make an MVC without jerking and as quickly as possible, for each of the muscle actions noted above. Force readings were taken from a load cell assembly through an analogue-to-digital converter and analyzed to yield time values for MVC, 3/4 MVC, 1/2 MVC, and 1/4 MVC. The results indicated significant differences (p < .01) between the responses of the men and women, with the women reaching full MVC more rapidly than the men. Also, there were significant differences among the five muscle groups tested, with the wrist flexor muscle group developing MVC most quickly, while the knee extensors took the longest time to full MVC. Based upon these data it may be concluded that the time to full MVC differs between men and women, and also that the time to full MVC differs among the five muscle groups tested in this experiment.  相似文献   
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The developmental trajectories of behavioral control and resiliency from early childhood to adolescence and their effects on early onset of substance use were examined. Behavioral control is the tendency to express or contain one's impulses and behaviors. Resiliency is the ability to adapt flexibly one's characteristic level of control in response to the environment. Study participants were 514 children of alcoholics and matched controls from a longitudinal community sample (Time 1 age in years: M =4.32, SD =0.89). Children with slower rates of increase in behavioral control were more likely to use alcohol and other drugs in adolescence. Children with higher initial levels of resiliency were less likely to begin using alcohol.  相似文献   
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We investigated risk factors in a population-based sample of alcoholic (father) and comparison families with 3-year-old sons. Alcoholic and comparison parents did not differ in socioeconomic status (SES), education, years married, family size, or cognitive functioning. Anti-social behavior and depression were significantly greater in alcoholic parents. High risk children were more impulsive than comparison children, but there were no differences in developmental age, IQ, or behavior problems. A higher percentage of high-risk children were rated in the extreme clinical range for behavior problems than were comparison children. For alcoholic families, mothers' ratings of their children's total behavior problems, externalizing behavior problems, and internalizing behavior problems were predicted by mothers' lifetime alcohol problems, current depression, and family SES. Father variables failed to predict children's behavior problems. Maternal variables were stronger predictors of their 3-year-old sons' problem behaviors than were paternal variables.  相似文献   
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Intelligent control systems are able to work well in uncertain nonlinear systems, mainly for: changes in the operating point, presence of environmental noise and disturbances, uncertainty in sensor measurements, miscalibration, uncertain model plant, and others. For instance, fuzzy controllers have been widely studied and applied. Recently, artificial organic controllers (AOC) have been proposed as an ensemble of fuzzy logic and artificial hydrocarbon networks. However, a weakness in AOC is the lack of training methods for tuning parameters for desired output responses in control. In this regard, this paper aims to introduce an evolutionary optimization method, i.e. particle swarm optimization, for tuning artificial organic controllers. Three objectives are proposed for automatic tuning of AOC: overall error, steady-state error and settling time of output response. The proposed methodology is implemented in the well-known cart-pole system. Also, the proposed method is applied on a one-leg unstable mechanism as case study. Results validate that automatic tuning of AOC over simulation systems can achieve suitable output responses with minimal overall error, steady-state error and settling time.  相似文献   
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ABSTRACT

Law librarians are well aware that it is difficult to maintain print and electronic collections in today's law library. The author of this article compares his personal experience in reference assistance and collection development with findings from the literature and from responses to an open-ended questionnaire. The author looks for trends and differences in reference assistance and collection development among academic, firm, and government law libraries.  相似文献   
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ABSTRACT

The research and practice surrounding student service members/veterans has evolved over several decades. With a regeneration of veteran students’ enrollment, a need for increased attention to this special student population continues to be an institutional priority, especially for community colleges. The literature suggests that while greater attention has been paid to serving those that have served, there is little to support whether or not such efforts are considered evidenced-based. This discussion asserts that community colleges are ripe with examples of evidenced-based programming for student service members and student veterans.  相似文献   
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