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Circadian rhythms of tonic immobility were found in male albino rats raised on a 12-h diurnal light cycle and tested at 6-h intervals. Durations of immobility were twice as long at 2000 h as at 1400 h. These differences persisted when rats were exposed to constant darkness for 10 days, but disappeared when rats were maintained in constant light for the same period. Since endogenous circadian rhythms of certain monoamine levels persist in constant darkness yet disappear under constant light, it is suggested that cycles of tonic immobility in rats are also endogenous. When the diurnal pattern of tonic immobility duration is compared to that of various neurohumors, immobility duration appears to parallel melatonin production and to be opposite in phase to the cycle of serotonin levels. Duration of immobility increased over trials, although the number of inductions required to produce immobility decreased. This suggests that instrumental conditioning may modify the immobility response to some extent. 相似文献
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The aim of this study was to investigate the acute effects of prior exercise (warm‐up and stretching) on the electromyographic and force output of mechanically elicited triceps surae reflexes. Fifty male subjects performed eight reflex experiments under each of three successive conditions in one session: (1) no prior exercise, (2) after static stretching of the passive triceps surae (3 min) and (3) after a 10‐min warm‐up run on a treadmill. Tendon tap reflex force was elicited in the triceps surae of the right leg by means of a standardized reflex hammer and measured in a custom‐built fixture. Electromyographic (EMG) signals were recorded with surface electrodes over the medial head of the gastrocnemius (G) and the soleus (S). Low coefficients of variation within subjects contrasted with high between‐subject variations, indicating highly individual reflex characteristics. After stretching, reductions in the peak force (‐5%; P < 0.05), the force rise rate (‐8%; P < 0.01), the half relaxation rate (‐5%; N.S.), the EMG amplitudes (G, ‐16%; S, ‐17%; P < 0.01) and integrals (G, ‐15%; S, ‐18%; P < 0.01), and an increase in EMG latencies (G, +3%; S, +1%; P < 0.01), were found compared with the values obtained without prior exercise. After running, the peak force reached the values obtained without prior exercise (‐2%; N.S.), the force rise rate and half relaxation rate increased by 8 and 12%, respectively (P < 0.01), and the impulse (force‐time integral; ‐12%), EMG amplitudes (G, ‐20%; S, ‐23%; P < 0.01), integrals (G, ‐18%; S, ‐23%; P < 0.01) and latencies (G, ‐1%; S, ‐2%; P < 0.01) decreased significantly. The changes in the force characteristics observed after the stretching treatment indicate improved muscle compliance that might reduce the risk of injury. On the other hand, the changes after the additional warm‐up run had a more pronounced influence with regard to improved force development and a decreased EMG activity, which can be viewed as a performance‐enhancing effect. 相似文献
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Motivation is a concept more frequently found in venues concerned with educational psychology than in ones concerned with educational philosophy. Under the influence of psychology, and its typically dualistic way of making sense of the world, motivation in education has tended to be viewed in dichotomous terms, for example, as intrinsic or extrinsic in character. Such psychology-derived theories of educational motivation operate within a dichotomous ontology, traceable to structuralist notions of agency versus (rather than within) structure, while exemplifying the tendency in psychology that philosopher R. S. Peters identified over half a century ago, of seeking to provide totalizing, comprehensive theories of human behaviour in emulation of the achievements of the natural sciences. This article offers an alternative reading of motivation in terms of Foucauldian ethical self-formation that attempts to recognize motivation as arising from the individuals’ socially situated and constrained agency, and that focuses on how individuals pursue learning as a way of creating a particular desired version of the self. We illustrate this approach through a vignette of Wolfgang, a Hong Kong learner of German as a third language. Although we are certainly not seeking to supplant other approaches to theorizing motivation, we believe that the approach we elaborate here contributes significantly to the repertoire of motivational research in education. 相似文献
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The aim of this study was to determine the response of cyclists to manipulations of cadence and power output in terms of force application and plantar pressure distribution. Two groups of cyclists, 17 recreational and 12 competitive, rode at three nominal cadences (60, 80, 100 rev min -1 ) and four power outputs (100, 200, 300, 400 W) while simultaneous force and in-shoe pressure data were collected. Two piezoelectric triaxial force transducers mounted in the right pedal measured components of the pedal force and orientation, and a discrete transducer system with 12 transducers recorded the in-shoe pressures. Force application was characterized by calculating peak resultant and peak effective pedal forces and positive and negative impulses. In-shoe pressures were analysed as peak pressures and as the percent relative load. The force data showed no significant group effect but there was a cadence and power main effect. The impulse data showed a significant three-way interaction. Increased cadence resulted in a decreased positive impulse, while increased power output resulted in an increased impulse. The competitive group produced less positive impulse but the difference became less at higher cadences. Few between-group differences were found in pressure, notable only in the pressure under the first metatarsal region. This showed a consistent pattern of in-shoe pressure distribution, where the primary loading structures were the first metatarsal and hallux. There was no indication that pressure at specific sites influenced the pedal force application. The absence of group differences indicated that pressure distribution was not the result of training, but reflected the intrinsic relationship between the foot, the shoe and the pedal. 相似文献
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The aim of this study was to determine the response of cyclists to manipulations of cadence and power output in terms of force application and plantar pressure distribution. Two groups of cyclists, 17 recreational and 12 competitive, rode at three nominal cadences (60, 80, 100 rev x min(-1)) and four power outputs (100, 200, 300, 400 W) while simultaneous force and in-shoe pressure data were collected. Two piezoelectric triaxial force transducers mounted in the right pedal measured components of the pedal force and orientation, and a discrete transducer system with 12 transducers recorded the in-shoe pressures. Force application was characterized by calculating peak resultant and peak effective pedal forces and positive and negative impulses. In-shoe pressures were analysed as peak pressures and as the percent relative load. The force data showed no significant group effect but there was a cadence and power main effect. The impulse data showed a significant three-way interaction. Increased cadence resulted in a decreased positive impulse, while increased power output resulted in an increased impulse. The competitive group produced less positive impulse but the difference became less at higher cadences. Few between-group differences were found in pressure, notable only in the pressure under the first metatarsal region. This showed a consistent pattern of in-shoe pressure distribution, where the primary loading structures were the first metatarsal and hallux. There was no indication that pressure at specific sites influenced the pedal force application. The absence of group differences indicated that pressure distribution was not the result of training, but reflected the intrinsic relationship between the foot, the shoe and the pedal. 相似文献
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The relationships among cooperation-competition, perceptions of locus of control in social situations, and perceptions of locus of control in intellectual-academic situations was compared among 89 fourth- and fifth-grade students in traditional and open classrooms. Children from the open education setting displayed substantially more cooperative behavior on Madsen's marble-pull game than children from the traditional school. They also made significant gains in cooperative behavior from the first to the second trial, while the difference between trials was not significant for the traditional students. Traditional students displayed significantly higher internality for locus of control in academic settings, while perceptions of locus of control in social settings did not differ for the two groups. Academic and social locus of control judgments were significantly correlated for the open education students, but not for the students from traditional classrooms. 相似文献
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Much relevant internet‐mediated information is inaccessible to people with learning disabilities because of difficulties in navigating the web. This paper reports on the methods undertaken to determine how information can be optimally presented for this cohort. Qualitative work is outlined where attributes relating to site layout affecting usability were elicited. A study comparing web sites of different design layouts exhibiting these attributes is discussed, with the emphasis on methodology. Eight interfaces were compared using various combinations of menu position (vertical or horizontal), text size and the absence or presence of images to determine which attributes of a site have the greatest performance impact. Study participants were also asked for their preferences, via a ‘smiley‐face’ rating scale and simple interviews. ‘Acquiescence bias’ was minimised by avoiding polar (‘yes/no’) interrogatives, achieved by asking participants to compare layouts (such as horizontal versus vertical menu), with reasons coaxed from those able to articulate them. Preferred designs were for large text and images. This was the reverse of those facilitating fastest retrieval times, a discrepancy due to preferences being judged on aesthetic considerations. Design recommendations that reconcile preference and performance findings are offered. These include using a horizontal menu, juxtaposing images and text, and reducing text from sentences to phrases, thus facilitating preferred large text without increasing task times. 相似文献
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Charles W. Hennig 《Learning & behavior》1979,7(1):106-110
The effects of physical environment, time in captivity, and distance between potential predator and prey on defensive behaviors were examined inAnolis carolinensis. When the experimenter was nearby, duration of immobility was significantly longer in the open than in areas with nearby foliage. However, this relationship between duration of immobility and the testing environment in the anole was reversed by Day 9 in captivity. Flight latency of anoles after termination of immobility was significantly shorter in anoles housed in terraria containing foliage, while greater incidence of freezing was shown by anoles housed in empty terraria. These results suggest that although the physical environment has strong effects on defense behaviors, the different defensive reactions are influenced in different ways. 相似文献