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41.
James E. Skinner Mark Molnar Tomas Vybiral Mirna Mitra 《Integrative psychological & behavioral science》1992,27(1):39-53
The application of “chaos theory” to the physical and chemical sciences has resolved some long-standing problems, such as how to calculate a turbulent event in fluid dynamics or how to quantify the pathway of a molecule during Brownian motion. Biology and medicine also have unresolved problems, such as how to predict the occurrence of lethal arrhythmias or epileptic seizures. The quantification of a chaotic system, such as the nervous system, can occur by calculating the correlation dimension (D2) of a sample of the data that the system generates. For biological systems, the point correlation dimension (PD2) has an advantage in that it does not presume stationarity of the data, as the D2 algorithm must, and thus can track the transient non-stationarities that occur when the systems changes state. Such non-stationarities arise during normal functioning (e.g., during an event-related potential) or in pathology (e.g., in epilepsy or cardiac arrhythmogenesis). When stochastic analyses, such as the standard deviation or power spectrum, are performed on the same data they often have a reduced sensitivity and specifity compared to the dimensional measures. For example, a reduced standard deviation of heartbeat intervals can predict increased mortality in a group of cardiac subjects, each of which has a reduced standard deviation, but it cannot specify which individuals will or will not manifest lethal arrhythmogenesis; in contrast, the PD2 of the very same data can specify which patients will manifest sudden death. The explanation for the greater sensitivity and specificity of the dimensional measures is that they aredeterministic, and thus are moreaccurate in quantifying the time-series. This accuracy appears to be significant in detecting pathology in biological systems, and thus the use of deterministic measures may lead to breakthroughs in the diagnosis and treatment of some medical disorders. 相似文献
42.
Quantification of a chaotic system can be made by calculating the correlation dimension (D2) of the data that the system generates
(Packard et al., 1980). The D2 algorithm, however, requires stationarity of the generator, a feature that biological data
rarely reflect (Mayer-Kress et al., 1988). So we developed the “point correlation dimension” (PD2), an algorithm that accurately
tracks D2 in linked data of different dimensions (Carpeggiani et al., 1991). We now present a mathematical argument that,
for stationary data, individual PD2s converge to D2 and we demonstrate that the algorithm rejects contributions made by bursts
of noise. Data were obtained from the surface of the olfactory bulb of the conscious rabbit (64 electrodes, 640 Hz each, 1.3
sec epochs) before and after presentation of a novel or habituated odor. D2 could be calculated in only 1 of 10 novel-odor
trials, whereas PD2 could be calculated in all. Both algorithms indicated that a novel odor evokes a spatially uniform dimensional
increase. The PD2 uniquely exhibited the dimensional decreases that occur during inspiration and the gradients of mean dimension
present during the nonstimulated control state. These control gradients remained unchanged without odor experience, but showed
spatially specific PD2 increases following odor habituation. It is interpreted that, 1) the PD2 issensitive, accurate, and appropriate for dimensional assessment of biological data, 2) that during analysis of unfamiliar information a singleglobal process is transiently evoked in the neuropil, and 3) after experience multiplespatially specific processes tonically map the sites of learning.
Grant Support: National Institutes of Health, HL 31164 and NS27745 相似文献
43.
James A. Bashford Keri R. Riener Richard M. Warren 《Attention, perception & psychophysics》1992,51(3):211-217
Outside of the laboratory, listening conditions are often less than ideal, and when attending to sounds from a particular source, portions are often obliterated by extraneous noises. However, listeners possess rather elegant reconstructive mechanisms. Restoration can be complete, so that missing segments are indistinguishable from those actually present and the listener is unaware that the signal is fragmented. This phenomenon, called temporal induction (TI), has been studied extensively with nonverbal signals and to a lesser extent with speech. Earlier studies have demonstrated that TI can produce illusory continuity spanning gaps of a few hundred milliseconds when portions of a signal are replaced by a louder sound capable of masking the signal were it actually present. The present study employed various types of speech signals with periodic gaps and measured the effects upon intelligibility produced by filling these gaps with noises. Enhancement of intelligibility through multiple phonemic restoration occurred when the acoustic requirements for TI were met and when sufficient contextual information was available in the remaining speech fragments. It appears that phonemic restoration is a specialized form of TI that uses linguistic skills for the reconstruction of obliterated speech. 相似文献
44.
A number of studies have demonstrated stable individual differences in the cues that generate emotions and other feeling states. These differences are assumed to arise from the cues parents use to identify their children's emotional states. As children learn about their own emotional states, they come to rely on these same cues. To test one implication of their view, the facial expressions of children (N=41) were manipulated and their feelings assessed. Some children reported emotions consistent with their expressions, while others reported emotions appropriate to the situation. In a separate procedure, their mothers were asked to identify the emotional states of children whose expressions were inconsistent with an account of their circumstances. Mothers who paid more attention to their children's expressive behavior had children who were more responsive to their own expressive behavior. In contrast, the mothers who were more responsive to situational cues had children whose emotions arose from the situational cues as well.The authors would like to thank numerous teachers and administrators of the Worcester Public School system in Worcester, Massachusetts, for their assistance. 相似文献
45.
Anthony Spirito James Overholser Lori J. Stark 《Journal of abnormal child psychology》1989,17(2):213-221
This study investigated the most common precipitants of adolescent suicide attempts and the strategies used to cope with such problems. Adolescent suicide attempters were compared with both distressed and nondistressed nonsuicidal adolescents on problems reported and coping strategies utilized. All three groups reported four problems as occurring most frequently: school, parents, friends, or boyfriend/girlfriend. The suicide attempters and distressed controls reported problems with parents more frequently than did nondistressed controls, while this latter group reported problems at school more frequently than did suicide attempters or distressed controls. Suicide attempters used social withdrawal, problem solving, and emotional regulation more than did nondistressed controls, but not more frequently than distressed controls. Distressed controls used wishful thinking and resignation more than did suicide atempters. Results are discussed in terms of the similarities between suicide attempters and nonsuicidal distressed adolescents and the need to more closely investigate specific subgroups of suicide attempters. 相似文献
46.
Current models of goal setting often fail to consider the potential negative effects of goal programs. Control over goal difficulty levels may be an important source of personal control in the workplace and psychological reactance may result from a shift in control over the setting of goals. The present experiment examined the effects of initial goal origin (assigned or self-set) and shifted goal origin (shifted or not shifted) on goal acceptance and attainment over two trial blocks of a verbal task. Several hypotheses based on psychological reactance theory were tested in a laboratory experiment with 160 college undergraduates. Overall analyses revealed significant interactions for goal acceptance and goal attainment over trial blocks. Simple effect analyses isolated this interaction for both dependent variables in a disordinal crossover pattern for the shifted origin groups over trial blocks, as expected. The discussion focuses on fitting these results into the current program guiding goal-setting research and on suggesting future avenues of research. Some implications for the application of goal setting are also discussed. 相似文献
47.
Responses to graphic horror films have been shown to be modified by a number of personality variables, and in particular, by gender-specific rules for social conduct. In earlier horror research it has been assumed that gender-specific responses are largely determined by biological gender. More recent research has focused on psychological patterns of gender identity that often transcend biological gender lines. This investigation sought clarification by examining the impact of individuals' self-perceived gender role and other personality characteristics on affective responses to horror. Subjects' perceptions of how same- and opposite-gender peers would respond to such materials were also assessed. Consistent with theoretical expectations, the findings revealed strong effects on the estimation of opposite-gender target's reactions as a function of both the rater's gender role characteristics and biological gender. Other personality factors were found to influence responses to horror only marginally, however. The results are discussed in terms of the gender role socialization model of affect. 相似文献
48.
James J. Jupp 《Counselling psychology quarterly》1989,2(4):441-450
Neurolinguistic programmers claim that individuals have preferred (primary) representational systems. These may be auditory, visual or kinesthetic and determine how a person views/deals with the world. Systems can be identified by observation of eye movements. In workshops programmers demonstrated strong associations between eye movements following questioning and types of questions and eye movement categories (assumed to identify systems) and other assessments of systems. Studies have evaluated these ‘workshop’ associations and found little support for their general occurrence. In these studies, it is possible that eye movements following questioning were influenced by artifacts which influence predicted association between these and other variables. An attempt was made to exclude these artifacts in this study. Except for subjects who had attended neurolinguistic workshops, results supported those obtained elsewhere. Possibly, associations in workshops occur as a result of expectational-contextual variables. 相似文献
49.
Walter Schneider 《Behavior research methods》1989,21(2):334-340
A computer virus is a program that replicates itself and spreads to computers with the goal of disrupting or destroying normal computer use. In academic computing, viruses represent a serious problem that costs millions of dollars in losses annually and hinders the free exchange of information so critical to education. Viruses operate in incubation, infection, and destroy phases. The nature, mechanisms, and preventive measures for personal-computer viruses are reviewed. Different procedures are recommended to protect research laboratories, instructional laboratories, and software lending libraries. Tradeoffs between providing adequate protection and not having the security become too burdensome are considered. 相似文献
50.