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This paper describes an amplifier for an electroencephalograph with gain of 1×104 to 1×106 and made entirely of commercially available IC components. The two-stage amplifier has a preamplifier stage with fixed gain of 1000, and a second stage with variable gain from 1 to 100. The final stage, an anti-aliasing filter, adds a gain of 10 to the signal. The circuit has high common mode rejection, low input bias current, very low noise characteristics, low offset voltages, and offset nulling capability built into the circuit. 相似文献
54.
A unique relationship exists between physicians and philosophers — one that expands on the constructive potential of the liaison between physicians and, for example, theologians, on the one hand, or, social workers on the other. This liaison should focus in the scientific aspects of medicine, not just the ethical aspects. Philosophers can provide physicians with a perspective on both the philosophy and the history of medicine through the ages — a sense of how medicine has adapted to the social cultural and ethical needs of each period. This perspective, while emphasizing medicine asscience, should not be limited to matters of methodology, or to criteria for distinguishing science from other intellectual pursuits, but should be concerned also with the history, sociology and politics of science. Both physicians and philosophers stand to gain from a strengthening of their active liaison now as never before; but most of all, the public will be the beneficiary. 相似文献
55.
Fear of Success (FOS) was originally conceived as a unidimensional motive. However, there is both theoretical and empirical
support for the hypothesis that FOS is multidimensional. We factor analyzed the responses of 236 undergraduates to twenty-oneConcern Over the Negative Consequences of Success items and found four factors. Our four factors show considerable overlap with dimensions based on theoretical accounts of
FOS etiology as well as with the factor structures obtained from two other factor analytic studies. Thus, there is converging
evidence that FOS is multidimensional. The relationship between multidimensional FOS and a multidimensional approach to achievement
motivation is discussed. 相似文献
56.
Seventh-grade students and teachers from twenty-three middle and junior high schools were surveyed to determine the association between teacher attitudes, behavioral intentions, and smoking behavior and the prevalence of student smoking. Teacher attitudes toward smoking policies were found to be strongly related to the current smoking behavior of the teacher but not consistently related to student smoking. In addition, teacher likelihood of intervening showed a modest association with teacher smoking status, with current smokers generally indicating being the least likely to intervene for student possession or use of cigarettes. Teacher intentions to intervene were strongly associated with the prevalence of smoking among boys but not girls. 相似文献
57.
Michael Harris Bond Kwok Leung Shalom Schwartz 《International journal of psychology》1992,27(2):211-225
A previous study (Leung, Bond, & Schwartz, 1990) established that an expectancy-valence model could be used effectively to explain behaviours in three social domains both within and across cultures. In this study the model was applied to the domains of resource allocation and conflict resolution in order to pinpoint which expectancies and which valences were carrying the explanatory weight of the respondents' behavioural strategies. For both Israeli and Hong Kong students the expectancies and, less strongly, the valences tapping harmony and performance quality were important for resource allocation; those tapping animosity reduction and process control, for conflict resolution. Suggestions were offered for broadening the net of explanatory constructs for future work aimed at specifying subjective factors associated with justice-related behaviours. 相似文献
58.
Zajonc's (1965) drive theory explanation argues that greater arousal tends to impair performance on difficult tasks. The hypothesis that arousal generated by “pressure situations” during major league baseball games would hinder batting performance—a difficult task—was tested by examining such performance during the 1989 season. Six “pressure situations” were identified, some occurring during the late innings of close games and others occurring throughout the game when there were two outs. Two measures of batting performance (batting average and slugging average) were employed. Results indicated broad support for the hypothesis. Reasons for this pattern are discussed, as are possible alternative explanations for these findings. 相似文献
59.
Effects of persuasive messages, responsibility denial (RD), and attitude-accessing on blood-giving attitudes, intentions, moral obligations, and behavior were examined. In Study 1, participants (n= 84) who heard a message emphasizing moral reasons for donating indicated a more favorable postmessage attitude and stronger moral obligation to donate than participants exposed to a message aimed at reducing fear, a combined moral and fear- reduction message, or no message. Combined message participants showed greatest intent to donate, yet only 14% of all participants attended a campus drive. In Study 2, low (n= 52) and high (n= 60) RD individuals heard the message arguments and were asked to access their attitudes. Low compared to high RD individuals stated a stronger sense of moral obligation, particularly when they accessed their thoughts relevant to blood donating, and behavioral intention, especially in the combined message condition. Few participants attended a blood drive (12.5%), yet most were low RD individuals from the nonaccessed attitude condition (83%). Results suggest that few individuals will engage in the altruistic act of blood donating, despite the experimental use of persuasive messages and accessing issue-relevant attitudes. 相似文献
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