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Emery W. Seymour 《Research quarterly for exercise and sport》2013,84(4):459-462
Abstract Venous blood pressure measurements were made by direct cannulation of the median antecubital vein. Measurements were taken at rest, during a 5-minute exercise on the bicycle ergometer, and during a 15-minute recovery period. The range of resting pressure was from 73 to 169 mm. water, with a mean pressure of 120 mm. water. The pressure during exercise increased in every case and was maintained throughout the exercise. The average increase was 118 mm. water, representing an increase of 95 percent. Venous pressure during recovery showed a very rapid drop during the first three minutes and then exhibited a progressively slower decline until a constant level was reached. 相似文献
94.
Quantum chemistry is based on the solution of the Schrödinger equation for a molecule. From starting data on the positions and nature of constituent atoms information is provided about the energy of the molecule and its electronic properties. The former can indicate what shapes drugs can adopt in binding to pharmacological receptors whilst electronic details, when compared using computer graphics, may highlight the factors responsible for biological activity. These techniques are beginning to show real successes in the design of drug molecules. 相似文献
95.
F. M. Reza 《Journal of The Franklin Institute》1985,320(6)
The normal family of linear (time-variant) n-ports is introduced as the most natural extension of ordinary scalar driving-point immittance behaviour. The normality induces a certain symmetry and simplicity which merits due emphasis in future n-port research investigations. As an application of the concept of normality the overdamped-underdamped criterion is extended to n-ports. Also, an interesting problem of maximal power transfer is solved and the absolute energy invariant index calculated. This paper invites attention to the development of circuit synthesis procedures based on the algebraic structure of the normal family. 相似文献
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Large-scale assessments often use a computer adaptive test (CAT) for selection of items and for scoring respondents. Such tests often assume a parametric form for the relationship between item responses and the underlying construct. Although semi- and nonparametric response functions could be used, there is scant research on their performance in a CAT. In this work, we compare parametric response functions versus those estimated using kernel smoothing and a logistic function of a monotonic polynomial. Monotonic polynomial items can be used with traditional CAT item selection algorithms that use analytical derivatives. We compared these approaches in CAT simulations with a variety of item selection algorithms. Our simulations also varied the features of the calibration and item pool: sample size, the presence of missing data, and the percentage of nonstandard items. In general, the results support the use of semi- and nonparametric item response functions in a CAT. 相似文献
98.
Gerald F. Smith 《Interchange》2001,32(4):349-374
Due to its strong focus on reasoning and argumentation, critical thinking lacks the breadth required of a comprehensive account of higher order thinking. In particular, critical thinking does not promote reflection on the underlying problems or situations that people think about. This paper reviews various proposed additions to and reorientations of the critical thinking paradigm. It presents a conceptual framework that encompasses the most promising extensions as topics in a broadened account of higher order thinking. This account can be understood as an elaboration of problem solving along two dimensions: Problem types, which are generic thinking situations; and problem solving functions, which are generic thinking tasks. The proposed topic-level account of higher order thinking offers a greatly enlarged view of what should be taught in general thinking skills programs. 相似文献
99.
This study examined the factor structure of the Emotional Autonomy Scale (EAS) as proposed by Steinberg and Silverberg. Participants were from three independent samples of adolescents in grades 6 (n = 1,842), 8 (n = 1,769), and 10 (n = 1,232), with each sample consisting of three ethnic groups: African American, European American, and Mexican American. None of the confirmatory factor analyses for these samples supported the factor structure proposed by Steinberg and Silverberg. From the three models tested, the EAS is best described by the four originally proposed factors, combined with two method factors, one consisting of the positively worded scale items and one consisting of the negatively worded scale items. Results show that the EAS exhibits poor construct validity and behaves quite differently for the different grade and ethnic groups. The strong impact of method variance on the factor structure is discussed. Although various alternative solutions to the psychometric problems in the EAS are proposed, the most credible solution may be to reexamine the conceptual foundations of emotional autonomy and develop better measures of those concepts for adolescents. 相似文献
100.
The present research examined the role of maladaptive self-regulatory beliefs as vulnerability factors for academic and emotional difficulties during the transition to middle school. A short-term longitudinal design was employed to follow two groups of early adolescents: 187 adolescents who experienced a school transition between the fifth and sixth grades, and 142 adolescents who did not experience a school transition between the fifth and sixth grades. Adolescents completed measures of perceptions of academic control and importance of academic success, experience of chronic academic strain, daily school hassles, and depressive symptoms. Teachers reported on students' academic engagement, including levels of helpless behavior, effort, and academic performance. Consistent with the proposed model of self-regulation, maladaptive self-regulatory beliefs (i.e., decreased perceptions of academic control and importance) predicted individual differences in perceived school-related stress and depressive symptoms over the course of the middle school transition, but were not associated with academic and emotional difficulties in adolescents who remained in a stable school environment. Moreover, a self-regulatory sequence was identified proceeding from maladaptive self-regulatory beliefs, to academic disengagement, to enhanced perceptions of school-related stress, to depressive symptoms. This study bridges prior theory and research concerning the psychological impact of normative developmental transitions, the developmental context of depression, and the associations among self-regulatory beliefs, achievement-related behavior, and emotional experience. 相似文献