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941.
Control theory was used to investigate identity microprocesses (i.e., self-verification)within the context of serious dating relationships. Forty-two college women importance for, and certainty about, their future career identities served as targets in the study. The targets and their dating partners participated in a procedure in which the targets received career information that was contrary to their beliefs about their future identities. Results revealed that women who were highly certain about their future career identity, regardless of its importance level, engaged in more self-verification efforts than did women who were uncertain. A comparison of congruent (partner herself) and incongruent dating partners revealed that congruent partners were the most overt in their disagreement with the contrary information. Certainty and partner congruence predicted the target's self-rating change following the identity disruption. Partner congruence accounted for a substantial amount of variance in self-rating change, indicating that close relationships provide an influential context for identity development.  相似文献   
942.
A literature search was conducted on studies of new drugs used with patients with schizophrenia reported by U.S. and non-U.S. researchers from 1966–1993, yielding 41 U.S., and a total of 24 other non-U.S. studies, among them 11 British studies. Results of the U.S. and non-U.S. studies were pooled separately and compared. Among several comparable conditions discussed, the lack of any data on suicides in the U.S. studies was observed. For a second statistical analysis of suicide rates ‘person-years’ were calculated to adjust for differing washout durations. The results obtained include findings that the percentage of patients relapsing in U.S. studies was slightly lower (37.9%) than in non-U.S. studies (46%); the percentage of patients dropping out in U.S. studies (10.5%) was higher than in non-U.S. studies (7.6%); known location of dropout patients in U.S. studies was 1.7%, compared to 2.6% in non-U.S. studies. The most interesting finding was that no suicides were reported in U.S. studies, compared to 0.6% of patients reported in British studies. Some U.S. studies used ‘challenge doses’, such as amphetamines or L-dopa; no non-U.S. studies reported their use. Compared to U.S. studies, those by non-U.S., and particularly British, researchers appeared to report adverse events in their studies. ‘Challenge’ drugs were not used; suicides were reported. It is estimated that the probability that no patients suicided who participated in the U.S. is small—one in 500.  相似文献   
943.
What features of brain processing and neural development support linguistic development in young children? To what extent is the profile and timing of linguistic development in young children determined by a pre-ordained genetic programme? Does the environment play a crucial role in determining the patterns of change observed in children growing up? Recent experimental, neuroimaging and computational studies of developmental change in children promise to contribute to a deeper understanding of how the brain becomes wired up for language. In this review, the muttidisciplinary perspectives of cognitive neuroscience, experimental psycholinguistics and neural network modelling are brought to bear on four distinct areas in the study of language acquisition: early speech perception, word recognition, word learning and the acquisition of grammatical inflections. It is suggested that each area demonstrates how linguistic development can be driven by the interaction of general learning mechanisms, highly sensitive to particular statistical regularities in the input, with a richly structured environment which provides the necessary ingredients for the emergence of linguistic representations that support mature language processing. Similar epigenetic principles, guiding the emergence of linguistic structure, apply to all these domains, offering insights into phenomena ranging from the precocity of young infant's sensitivity to speech contrasts to the complexities of the problem facing the young child learning the arabic plural.  相似文献   
944.
The auditory cortex of the mustached bat shows complex multiple frequency maps, because cortical neurons in several areas are tuned to particular combinations of signal elements. Different types of combination-sensitive neurons form computational maps in which information-bearing parameters for echolocation (biosonar) are represented systematically. Neuronal response properties and multiple-frequency and computational maps were considered to be created solely by divergent-convergent interactions of neurons in the 'ascending' system. However, we have found that the 'corticofugal' system also plays an important role. Neurons in an iso-best frequency (or echo delay) 'minicolumn' of the auditory cortex augment the auditory responses of subcortical neurons tuned to that frequency (or echo delay) and sharpen their tuning. At the same time, they reduce the response and shift the tuning of subcortical neurons tuned to other frequencies (or echo delays) away from the best frequency (or delay) of the cortical neurons. Cortical neurons mediate a highly focused positive feedback, incorporated with widespread lateral inhibition, via corticofugal projections. This 'egocentric selection' is expected to play an important role in self-organizing the central auditory system.  相似文献   
945.
This paper addresses some critical issues in the applicability of quantitative performance measures (including bibliometric, economic, and co-occurrence measures) to the assessment of basic research. The strengths and weaknesses of metrics applied as research performance measures are examined. It is concluded that metrics have a useful role to play in the evaluation of research. Each metric employed, whether bibliometric, economic, co-occurrence, or others, brings a new dimension of potential insight to the complex problem of research assessment. However, when used in a stand-alone mode, metrics can be easily misinterpreted and result in misleading conclusions. Metrics should be an integral part of a more comprehensive approach to research evaluation, in which the leading role is assumed by expert peer review. Under this structure, the reviewers must be broadly constituted, so that the technical correctness of the research approaches being taken (doing the job right) can be evaluated by technical experts and the correctness of the research target (doing the right job) can be evaluated as well. This comprehensive approach insures quality in the implementation of existing research paradigms and allows the introduction of revolutionary new research paradigms as well. The views contained in this paper are solely those of the author and do not represent the views of the Department of the Navy. Ronald Kostoff received a Ph.D. from Princeton University, performed technical and economic research at Bell Laboratories, managed energy programs at U.S. Department of Energy, was Director of Technical Assessment at the Office of Naval Research for many years and presently manages the Navy’s In-House Laboratory Independent Research Program.  相似文献   
946.
947.
Nonparametric regression techniques, which estimate functions directly from noisy data rather than relying on specific parametric models, now play a central role in statistical analysis. We can improve the efficiency and other aspects of a nonparametric curve estimate by using prior knowledge about general features of the curve in the smoothing process. Spline smoothing is extended in this paper to express this prior knowledge in the form of a linear differential operator that annihilates a specified parametric model for the data. Roughness in the fitted function is defined in terms of the integrated square of this operator applied to the fitted function. A fastO(n) algorithm is outlined for this smart smoothing process. Illustrations are provided of where this technique proves useful.  相似文献   
948.
The purpose of the present study was to investigate the degree to which foveal information is necessary for object identification. To explore this question, we used an artificial moving scotoma paradigm to eliminate a region of a currently viewed display in real time as a function of eye position. Subjects examined linear arrays of four line drawings of objects while their eye movements were recorded. Immediately following each array, a test probe was presented to test the degree to which the subject had identified those objects. Three conditions were compared, one in which a central foveal scotoma was created, one in which an extrafoveal scotoma was created, and a control condition in which the scotoma was absent. The main result was that identification accuracy was very good, but eye-movement behavior was disrupted when a foveal scotoma was present. These results suggest that foveal information is not necessary but is beneficial for perceptual encoding during object identification; the loss of foveal information can be overcome as long as compensatory extrafoveal processing is possible.  相似文献   
949.
In three experiments, asymmetries between the processing of crossed and uncrossed disparities were investigated. The target was a luminance-defined circle concentric to a fixation mark, viewed stereoscopically on a computer monitor for 105 msec. Fifteen disparities were presented according to the method of constant stimuli. Observers indicated the apparent direction of target depth relative to fixation. All experiments measured both the accuracy and latency of this response. Experiment 1 showed fewer errors and shorter reaction times for identifying crossed disparities. Experiments 2 and 3 replicated Experiment 1 and also showed that observers may often perceive a target in the direction opposite that prescribed by the disparity information. We propose that the asymmetries and reversals result from differences in computation of sign, not of magnitude. This notion is consistent with a scheme of continuous disparity tuning and accounts for such asymmetries and errors without positing disparity pooling mechanisms.  相似文献   
950.
Older (n = 12) and younger (n = 12) golfers attempted to hit a golf ball into a target net a short distance away. An accelerometer attached to the back of the clubhead measured the applied force. In contrast to the more typical finding of slower perceptual-motor performance by older adults, older golfers reached their peak downswing force earlier in the shot and also exhibited a trend toward a faster overall speed or tempo of the shot. Additionally, older golfers exhibited greater changes in applied force and greater variability. A pattern of divergence among the force-time histories from multiple shots suggested that the overall person-plus-golf-club dynamics were unstable during a part of the shot. Older adults may be slower in controlling this instability. Half of the participants heard a tone whose pitch was proportional to their force. These participants had a slower follow through; however, they did not make significantly more or fewer shots than participants who had not been presented with the tone. Analyses of the temporal covariation among the backswing, downswing, and follow-through favored a chain-like temporal structure over a hierarchical, proportional structure. The pattern of covariation suggests that the tempo and rhythm of the shot are not independent and that changing one's tempo may disrupt rhythm.  相似文献   
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