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101.
Paul C. Kainen 《Journal of The Franklin Institute》2004,341(4):391-399
It is shown that cartesian product and pointwise-sum with a fixed compact set preserve various approximation-theoretic properties. Results for pointwise-sum are proved for F-spaces and so hold for any normed linear space, while the other results hold in general metric spaces. Applications are given to approximation of Lp-functions on the d-dimensional cube, 1?p<∞, by linear combinations of half-space characteristic functions; i.e., by Heaviside perceptron networks. 相似文献
102.
Two property regimes for software development may be distinguished. Within corporations, on the one hand, a Private Regime obtains which excludes all outsiders from access to a firm's software assets. It is shown how the protective instruments of secrecy and both copyright and patent have been strengthened considerably during the last two decades. On the other, a Public Regime among hackers may be distinguished, initiated by individuals, organizations or firms, in which source code is freely exchanged. It is argued that copyright is put to novel use here: claiming their rights, authors write ‘open source licenses’ that allow public usage of the code, while at the same time regulating the inclusion of users. A ‘regulated commons’ is created. The analysis focuses successively on the most important open source licenses to emerge, the problem of possible incompatibility between them (especially as far as the dominant General Public License is concerned), and the fragmentation into several user communities that may result. 相似文献
103.
Cultural Studies of Science Education - The hope for multicultural, culturally competent, and diverse perspectives in science education falls short if theoretical considerations of whiteness are... 相似文献
104.
Paul H. Smith 《Cambridge Journal of Education》2019,49(2):163-179
Student-mothers who study vocationally related higher education programmes are a relatively under-researched group. Specifically, there is a paucity of research into the emotions that these learners experience. This article discusses a qualitative investigation that examined the emotional narratives that a group of vocational student-mothers offered. They were studying for a foundation degree for teaching assistants at a university in the North of England. The student-mothers were largely found to have experienced positive emotions. However, familial and workplace guilt had also been encountered. These emotions emanated from notions about how family and workplace time should be used. Student-mothers managed this cognitive dissonance by stressing the reciprocal relationships that existed between their studies, family lives and school work. However, for many of these learners familial and workplace guilt was a strong and continuing emotion. 相似文献
105.
106.
Paul A. McDermott 《Psychology in the schools》1980,17(1):12-24
Focus is directed upon the logic and import of the assumption that effective preventative and remedial mental health service demands reasonable agreement among service providers as to the nature and course of psychological problems. The study proceeds to test the belief that school psychologists improve in diagnostic agreement as a function of increased training and experience. Seventy-two randomly selected members of groups of novice, intern, and expert school psychologists were presented with three child case studies containing a full breadth of information and were subsequently asked to render diagnoses. It was found that diagnostic agreement was absent at all levels of experience, and further, a trend was noted wherein school psychologists tended to demonstrate increasing disagreement with one another as they acquired more training and experience. The findings were examined in the context of comparative research from allied mental health and educational specialties, with a special concern for discovering prevailing patterns of decision-making errors that result in reduced diagnostic agreement and validity. 相似文献
107.
In this study, we examined the effects of different work:rest durations during 20 min intermittent treadmill running and subsequent performance. Nine males (mean age 25.8 years, s = 6.8; body mass 73.9 kg, s = 8.8; stature 1.75 m, s = 0.05; VO(2max) 55.5 ml x kg(-1) x min(-1), s = 5.8) undertook repeated sprints at 120% of the speed at which VO(2max) was attained interspersed with passive recovery. The work:rest ratio was constant (1:1.5) with trials involving either short (6:9 s) or long (24:36 s) work:rest exercise protocols (total exercise time 8 min). Each trial was followed by a performance run to volitional exhaustion at the same running speed. Testing order was randomized and counterbalanced. Heart rate, oxygen consumption, respiratory exchange ratio, and blood glucose were similar between trials (P > 0.05). Blood lactate concentration was greater during the long than the short exercise protocol (P < 0.05), whereas blood pH was lower during the long than the short exercise protocol (7.28, s = 0.11 and 7.30, s = 0.03 at 20 min, respectively; P < 0.05). Perceptions of effort were greater throughout exercise for the long than the short exercise protocol (16.6, s = 1.4 and 15.1, s = 1.6 at 20 min, respectively; P < 0.05) and correlated with blood lactate (r = 0.43) and bicarbonate concentrations (r = 0.59; P < 0.05). Although blood lactate concentration at 20 min was related to performance time (r = - 0.56; P < 0.05), no differences were observed between trials for time to exhaustion (short exercise protocol: 95.8 s, s = 30.0; long exercise protocol: 92.0 s, s = 37.1) or physiological responses at exhaustion (P > 0.05). Our results demonstrate that 20 min of intermittent exercise involving a long work:rest duration elicits greater metabolic and perceptual strain than intermittent exercise undertaken with a short work:rest duration but does not affect subsequent run time to exhaustion. 相似文献
108.
The purpose of this study was to compare submaximal physiological responses and indices of mechanical efficiency between asynchronous and synchronous arm ergometry. Thirteen wheelchair-dependent trained athletes performed eight steady-state incremental bouts of exercise (0 to 140 W), each lasting 4 min, using synchronous and asynchronous arm-cranking strategies. Physiological measures included oxygen uptake (VO2), heart rate, and blood lactate concentration. The power outputs corresponding to fixed whole blood lactate concentrations of 2.0 to 4.0 mmol x l(-1) were calculated using linear interpolation. Mechanical efficiency indices - gross efficiency, net efficiency, and work efficiency - were also calculated. An analysis of variance with repeated measures was applied to determine the effect of crank mode on the physiological parameters. Oxygen uptake was on average 10% lower (P < 0.01), and both net efficiency (P < 0.01) and gross efficiency (P < 0.01) were higher, during the asynchronous strategy at both 60 and 80 W (gross efficiency: 16.9 +/- 2.0% vs. 14.7 +/- 2.4% and 17.5 +/- 1.8% vs. 15.9 +/- 2.6% at 60 and 80 W respectively). There were no differences in heart rate, blood lactate concentration or power output at either of the blood lactate reference points between the asynchronous and synchronous strategies (P > 0.05). In conclusion, test specificity is an important consideration. If a synchronous strategy is to be adopted, it is likely to result in lower efficiency than an asynchronous strategy. The exercise testing scenario may help dictate which method is ultimately chosen. 相似文献
109.
110.