12 resultados para task performance

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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Repeated daily treatment with the catecholamine-depleting agent, reserpine, dramatically reduced performance on the delayed response task, a test of spatial working memory that depends upon the integrity of the prefrontal cortex. Delayed response performance fell from an average of 27.2/30 trials correct before reserpine treatment to an average of 20.4/30 trials correct after repeated reserpine administration. Injection of the alpha2-adrenergic agonist, clonidine (0.0001-0.05 mg/kg), to chronic reserpine-treated monkeys significantly restored performance on the delayed response task; performance after an optimal dose averaged 27.8/30 trials correct. Clonidine's beneficial effects on delayed response performance were longlasting; monkeys remained improved for more than 24 h after a single clonidine injection. The finding that clonidine is efficacious in reserpinized animals supports the hypothesis that alpha2-adrenergic agonists improve cognitive function through actions at postsynaptic, alpha2-adrenergic receptors on non-adrenergic cells. In contrast to the delayed response task, reserpine had little effect on performance of a visual discrimination task, a reference memory task which does not depend on the prefrontal cortex. These results emphasize the importance of postsynaptic alpha2-adrenergic mechanisms in the regulation of working memory,

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Our previous studies demonstrated that huperzine A, a reversible and selective acetylcholinesterase inhibitor, exerts beneficial effects on memory deficits in various rodent models of amnesia. To extend the antiamnesic action of huperzine A to nonhuman primates, huperzine A was evaluated for its ability to reverse the deficits in spatial memory produced by scopolamine in young adult monkeys or those that are naturally occurring in aged monkeys using a delayed-response task. Scopolamine, a muscarinic receptor antagonist, dose dependently impaired performance with the highest dose (0.03 mg/kg, i.m.) producing a significant reduction in choice accuracy in young adult monkeys. The delayed performance changed from an average of 26.8/30 trials correct on saline control to an average of 20.2/30 trials correct after scopolamine administration. Huperzine A (0.01-0.1 mg/kg, i.m.) significantly reversed deficits induced by scopolamine in young adult monkeys on a delayed-response task; performance after an optimal dose (0.1 mg/kg) averaged 25.0/30 correct. In four aged monkeys, huperzine A (0.001-0.01 mg/kg, i.m.) significantly increased choice accuracy from 20.5/30 on saline control to 25.2/30 at the optimal dose (0.001 mg/kg for two monkeys and 0.01 mg/kg for the other two monkeys). The beneficial effects of huperzine A on delayed-response performance were long lasting; monkeys remained improved for about 24 h after a single injection of huperzine A. This study extended the findings that huperzine A improves the mnemonic performance requiring working memory in monkeys, and suggests that huperzine A may be a promising agent for clinical therapy of cognitive impairments in patients with Alzheimer's disease.

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提出了一种基于数据包络分析的软件任务性能基准评价新方法——TaskBeD.介绍了TaskBeD的任务基准评价模型和核心算法(挖掘高性能的软件任务,建立参考任务集和结果的敏感度分析).实验结果显示,TaskBeD能够高效处理多变元和可变规模收益任务数据.

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Accumulating studies have been conducted on job burnout in the fields of organizational psychology and health psychology, but there are few studies investigating job burnout for people in the Chinese Armed Police Force(CAPF). This thesis explored the antecedents (social comparison, perceived control and perceived organizational support) and outcomes (incumbents’ level of task performance and psychological health) of job burnout, using data collected from 458 teachers (study 1) and 792 officers (470 lower level army cadres,150 commandos and 172 teachers, study 2) in CAPF. Two studies were carried out. The results are as follows: 1. There were significant differences among the three dimensions of job burnout for teachers: reduced accomplishment was rated significantly higher than cynicism and emotional exhaustion. 2. For the emotional exhaustion dimension, special technical soldiers gave the highest ratings and cadres provided the lowest ratings. Besides, special technical soldiers and teachers rated higher on cynicism than cadres did. 3. Perceived control significantly influenced job burnout: the higher the perceived control, the lower the three dimension of job burnout (emotional exhaustion, cynicism and reduced accomplishment). 4. Perceived control exerted impacts on psychological health directly and indirectly: the higher the perceived control, the better psychological health. Moreover, perceived control had significant effects on psychological health through emotional exhaustion: the higher the perceived control, the lower emotional exhaustion and the better psychological health. 5. The higher perceived organizational support, the lower the three dimensions of job burnout; perceived organizational support impacted psychological health through emotional exhaustion: the higher perceived organizational support, the lower emotional exhaustion and the better psychological health. 6. Job burnout exerted significant influence on task performance: the higher reduced accomplishment, the lower task performance rated by participants themselves. Drawing on the above results, measures would be taken in CAPF to enhance perceived control and perceived organizational support, to alleviate burnout and improve task performance and psychological health.

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Work engagement (WE) has recently become a fashionable term among Human Resource practitioners and Organizational Behavior researchers. However, academic research that has theoretically examined WE at the psychological level is limited, as is research on its place among other job attitude constructs that are used to describe employees at work, and its antecedents and consequences. This dissertation addresses a number of issues with regard to the discriminant validity of WE, the influences of WE and the mediating role of affective commitment, and the interaction effects of different job demands, job resources and personal resources on WE. The major findings are listed as follows: Firstly, the concept of WE is different from JB and job involvement (JI), and is more positively related to quality of employees’ work and life than the other two concepts. Specifically, WE is more related to employees’ creative performance than JB does; compared with JI, WE can better predict task performance, creative performance, organizational citizenship behavior (OCB), and life satisfaction; although both WE and JB cause work to family conflict, WE improves employees’ life satisfaction, while JB is deleterious to life satisfaction. Secondly, WE influences employees’ work and life directly or through the mediation effect of affective commitment. Specifically, WE reduces employees’ turnover intention and increase their OCBs by the the mediation effect of effective commitment. Furthermore, WE is positively related to task performance, creative performance, and life satisfaction directly. Thirdly, challenge job demands influence WE by the mediation effect of intrinsic motivation, and the impact of challenge job demands on WE is moderated by perceived supervisor support and growth needs. Specifically speaking, challenge job demands enhance employees’ intrinsic motivation, therefore boost WE. Employees with higher growth needs are more likely to be motivated by challenge job demands. In other words, the moderation effect of growth need is mediated by intrinsic motivation. In addition, those who perceive more supervisor support have higher level of WE when challenge job demands are high.

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Interface has been becoming a more significant element today which influences the development of shopping on-line greatly. But in practice the attention arisen from society and study made are quite inadequate. Under this circumstance, I focus my study on the purpose of improving understanding of the engineering psychological factors, which definitely will play a crucial role in shopping on-line representation in future, and of the relations between them through the following experimental research. I hope it can give a basic reference to the practical application of shopping on-line representation pattern and continuous study. In current thesis, an analysis was made on the basis of engineering psychology principles from three aspects, i.e. person (users), task and information environment. It was considered that system overview and information behavior model would have great impact on the activities of users on the web and that representation pattern of information system would affect the forming of system overview and behavior pattern and then further after the performances of users in information system. Based on above-mentioned statement, a three-dimensional conceptual model was presented which demonstrates the relations between the crucial factors, which are media representation pattern, system hierarchy and objects in information unit. Thereafter, eight study hypothesis, which are about engineering psychological factors of virtual reality (VR) representation in shopping on-line system, was taken out and four experiments were followed up to testify the hypothesis. -In experiment one, a research was made to study how the three kinds of single media representation pattern influence the forming of system overview and information behavior from the point view of task performance, operating error, overall satisfactory and mental workload etc. -In experiment two, a study of how the combined media representation pattern of system hierarchy influences users' behavior was carried out. -In experiment three, a study of the hierarchy structure feature of VR representation pattern and the tendency of its width and depth to the effects of system behavior was made. -In experiment four, a study of the location relations between different parties in VR scene (information unit) was made. The result is as follows: -During structure dimensional state: Width-increasing caused more damage to the speed of users than depth-increasing in VR representation pattern. Although the performance of subjects was quite slow in wider environment, yet the percentage rate of causing errors was in lowest level. -During hierarchy representation pattern: 1. Between the representation patterns of the three media, no significant differences was found in terms of the speed of fulfilling the task, error rate, satisfactory, mental workload etc. But the pattern with figure- aided gained the worst results on all of these aspects. 2. During primary stage of the task and the first level of the hierarchy, the speed of subjects' performance in VR pattern was slower than that in text pattern. While with developing of the task and going deeper level of the hierarchy, the speed of users' performance in VR representation pattern reached to the highest level. 3. Effects in VR representation pattern was better than that in text pattern in higher level of the system. The representation pattern in highest level has greatest impact on the performance of the system behavior, whereas results of the only VR representation in the middle part of hierarchy would be worst. 4. Activity error in single media representation pattern was more than that in combined media representation pattern. 5. Individual differences among subjects had effects on the representation pattern of the system. During VR environment, behavior tendency of party A had a significant negative correlation to the quantities of errors. -In VR-scene representation: Physical-distance and flash influenced the subjects' task performance greatly, while psychological-distance has no outstanding impact. Subjects' accurate rate of performing increased if objects with same relation were in the same structure position, in the state of close psychological-distance or if the object target flashed (not reliable). Although the article limits the topic only on the present-existing questions and analysis of shopping-on-line, as a matter of fact, it can also apply for other relevant purposes on the web. While the study of this article only gives its emphasis on the researching-task with definite goal, making no consideration of other task conditions and their relations with other navigation tools. So I hope it lay a good start to make continuous research in this areas.

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This research aims to discuss it is the complexity of interpersonal association and job autonomy that influence the predictive validity of personality for job performance. In addition, for service profession, incumbents' personality can predict not only contextual performance, but also task performance. Salesclerks in shopping center and life insurance agents are selected as subjects. The job performance rating scale is produced by using Critical Incidents Technique. The research method is measuring NEO-PI and collecting direct supervisors' rating of salespeople's job performance. The research results are as follows: 1. The factor analysis result of job performance is different from the west. That is to say, the support for organizations which belongs to contextual performance in the west can not be distinguished from task performance. Therefore, in China, or to say in the shopping center selected, task performance includes both technical proficiency and the support for organizations, and contextual performance includes job dedication and interpersonal facilitation. 2. For salespeople, personality can be the antecedent of contextual performance and task performance as well. However, the predictive validity for task performance is very low. 3. The more complexity of interpersonal association, the stronger relationship between personality and job performance. 4a. The correlation between job performance and facets of Big Five is higher than the one between job performance and factors of Big Five, such as Agreeableness, whose facets have different impacts on job performance, some positive and others negative. 4b. The correlation between personality and the items of job performance rating scale is higher than the one between personality and the factors of job performance. 4. Working experience is the moderator of the relationship between personality and job performance. For salesclerks, only if the working experience of subjects is less than 3 years, achievement striving-one facet of conscientiousness-is significantly correlated with the ratio of finished sales volume at 0.01 level.

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In the present study, we examined the effects of exposure to an extremely low-frequency magnetic field of 1 mT intensity on learning and memory in Lohmann brown domestic chicks using detour learning task. These results show that 20 h/day exposure to a low

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The objective of this study was to determine if the responses of basal forebrain neurons are related to the cognitive processes necessary for the performance of behavioural tasks, or to the hedonic attributes of the reinforcers delivered to the monkey as

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Rationale: Discriminating right from left is an everyday cognitive ability. Repeated exposure to certain drugs, such as heroin, can produce poor performance on many cognitive tasks. However, it is yet unclear whether drug abuse impairs the ability of right-left discrimination. Objectives: The aim of the present study is to examine whether the spatial ability measured by the right-left discrimination task can be affected by heroin abuse and whether such drug effect, if it exists, is gender related. Methods: A paper-and-pen test was used. The test consists of line drawings of a person with no arm, one arm, or both arms crossing the vertical body axis of the figure. The line drawings are viewed from the back, from the front, or randomly alternating between the back and front drawings. The subjects task is to mark which is the right or left hand in the figure as fast as possible. Results: A main finding in this study was that the ability to discriminate between left and right in visual space was impaired in heroin-dependent patients. Especially, heroin-dependent females performed poorer than control females in all conditions but heroin-dependent males only performed poorly in part of conditions. Conclusions: Recent heroin abuse impairs the ability of right-left discrimination and such impairment is gender related: heroin-dependent females demonstrated greater performance deficits than males.

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The D2 dopamine (DA) receptor agonist, quinpirole, was characterized in young adult monkeys, young reserpine-treated monkeys and aged monkeys to assess the contribution of DA to age-related loss of prefrontal cortical (PFC) cognitive function, Monkeys were tested on a delayed response memory task that depends on the PFC, and a fine motor task that taps the functions of the motor cortex, In young adult monkeys, low quinpirole doses impaired performance of the PFC and fine motor tasks, while higher doses improved memory performance and induced dyskinesias and ''hallucinatory-like'' behaviors. The pattern of the quinpirole response in reserpine-treated monkeys suggested that the impairments in delayed response and fine motor performance resulted from drug actions at D2 autoreceptors, while the improvement in delayed response performance, dyskinesias and ''hallucinatory-like'' behaviors resulted from actions at postsynaptic receptors. In aged monkeys, low doses of quinpirole continued to impair fine motor performance, but lost their ability to impair delayed response performance. The magnitude of cognitive improvement and the incidence of ''hallucinatory-like'' behaviors were also reduced in the aged animals, suggesting some loss of postsynaptic D2 receptor function, The pattern of results is consistent with the greater loss of DA from the PFC than from motor areas in aged monkey brain (Goldman-Rakic and Brown, 1981; Wenk et al., 1989), and indicates that DA depletion contributes significantly to age-related cognitive decline.