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Some properties are discussed of regular polygons that may result from angular homeostatic processes in stable orbit. To characterize these homeostatic polygons we need to discuss the winding number, the sidedness (integer, fractional and irrational), multiplicity, envelopes, and density. A regular (i.e., equilateral, equiangular) polygon may be closed in one revolution about its unique center, in multiple revolutions, or not at all. A homeostatic polygon can be generated only if all vertices are included in a single polygon, which occurs if and only if the number of vertices and the number of revolutions required to complete the polygon are relatively prime. For the homeostatic polygon to have a finite number of sides (without repeating itself) the angle subtended by any two successive vertices at the center must be a rational multiple of 2. Biological implications of these properties are illustrated.  相似文献   
23.
Previous research has indicated that adolescents who intend to smoke differ from those who do not intend to smoke in the imagery they associate with smoking. The present study examined relationships among self-image, ideal self-image, image of smokers in general and image of models in cigarette ads for seventh-grade students. The strongest finding was a positive correspondence of smokers image to self-image in predicting intention to smoke cigarettes. This correspondence between smokers image and self-image derived from a relative depression of self-image in combination with a relative elevation of smokers image for youth who were more likely to report intentions to smoke. There was also a trend for the ideal self-image of youth with greater intentions to smoke to be similarly depressed. It is suggested that when both self-concept and aspirations for self-improvement are diminished, smoking may seem particularly desirable as a means of enhancing identity.  相似文献   
24.
We evaluated a procedure for identifying potential reinforcers with profoundly retarded individuals. In Experiment 1, six persons were repeatedly exposed to 16 stimuli, and approach behaviors to each stimulus were used to identify preferred and nonpreferred stimuli. In Experiment 2, we examined the reinforcing properties of preferred and nonpreferred stimuli by delivering them contingently on the occurrence of arbitrarily selected responses. Results revealed that the preferred stimulus conditions typically produced higher rates of responding than did either the baseline or the nonpreferred stimulus conditions, suggesting that the procedure can be used to assess reinforcer value for individuals with limited behavioral repertoires.  相似文献   
25.
The ability of first- and third-grade children and college adults to make excuse inferences about a speaker's use of an utterance and to modify those inferences appropriately upon receiving later information was examined in four experiments. Short stories containing an utterance by a speaker were read aloud. Utterances in the story were preceded by contextual information that suggested either that the speaker was truthful or making an excuse. Utterances were followed by information that confirmed or disconfirmed the excuse interpretation. The results of Experiment 1 indicated that even first and third graders can make excuse inferences, but these children rarely modify these interpretations upon receiving disconfirming information. In Experiments 2–4 possible reasons for the children's interpretive inflexibility were examined by varying the difficulty of relating the excuse interpretation and succeeding information. Results suggested processing difficulty, as well as an interpretive “set,” contributed to the children's inflexibility.  相似文献   
26.
The publication in 1973 of Student Counselling in Practice signalled a new phase in the development of both careers and counselling services in the tertiary sector. The emergence of the professional careers adviser in higher education is described alongside the key role of the Association of Graduate Careers Advisory Services. The gradual professionalisation of student counselling is shown to have taken a different form, as a result of the policies of the Association for Student Counselling with its insistence on role definition and the accreditation of practitioners. Developments in further education are briefly reviewed, and a final section considers the present situation and possible future trends.  相似文献   
27.
At the work site, smoking accounts for increased health care expenses and worker absenteeism due to smoking-related illness and reduced productivity and lost wages. Developing comprehensive and accessible smoking cessation programs at the work site is an important objective for health care professionals. In this study, employees of 43 corporations participated in a televised smoking cessation program accompanied by self-help manuals. The media component involved presenting a smoking cessation program on a network television affiliate station during the 4:30 p.m. and 10:00 p.m. news for 20 days. Employees at half the corporations also had access to semiweekly self-help group meetings. Adding self-help support groups to a program involving self-help manuals and the media reports was found to significantly increase abstinence and its maintenance over time. The implications of using the media, self-help groups, and work site locations in large-scale community-based interventions are discussed.  相似文献   
28.
The relation of task strategy planning to task performance was explored using a series of laboratory investigations. The first study examined the influence of providing a subject a work strategy and a specific work goal on his or her subsequent performance. A total of 72 subjects participated in a 2 (goal) × 2 (task strategy priming) × 3 (performance period) × 3 (task type) repeated measures, factorial design study. The results demonstrate that task strategy priming and goal setting increase the amount of an individual's planning and directs the type of plan developed. A second study was conducted (n = 90) to further explore the effect of task strategy priming on planning and performance. Taken together, the results of the studies demonstrate that (a) goal setting increases strategic planning, (b) priming influences the amount and type of planning engaged in by an individual, and (c) task performance varies as the result of the type of plan an individual develops. The results are discussed as a means of expanding the use of cognitive constructs in theories of work motivation.  相似文献   
29.
Effective overall performance in judgment tasks generally involves both acquisition of information and integration of the information acquired. When information is costly the decision maker must balance acquisition costs against improved decisional accuracy, a complex balancing problem in which, laboratory evidence suggests, humans often do poorly. The three experiments reported here extend this earlier evidence to different task structures, subject pools, incentive systems, information volumes, decision aids, and kind of data sources. Though each of these factors was found to affect performance, the general finding was of persistent underpurchase (buying less information overall than is optimal) and mispurchase (buying poor sources when better sources are available at the same cost), with significant inflation of overall costs. It is proposed that unaided human judgment is unequal to the complexity of the cost/benefit trade-offs involved in acquiring costly information, and that formal decision analysis should be preferred whenever the stakes justify.  相似文献   
30.
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