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41.
42.
Stress can disrupt endocrine signalling in the male reproductive axis through high concentrations of glucocorticoids, the hallmark of stress. Our previous work revealed that a stress level of exogenous glucocorticoids could induce apoptosis of rat Leydig cells, which are the primary source of testosterone. The aim of this study was to investigate whether stress can induce apoptosis in rat Leydig cells in vivo and, if so, whether the process is the result of a direct effect of glucocorticoids. In a chronically stressed rat model, serum corticosterone concentration was increased significantly whereas serum testosterone was decreased. The frequency of apoptotic Leydig cells in stressed rats was also increased. Adrenalectomised rats subjected to chronic stress showed an elevated serum testosterone, while the apoptotic frequency of Leydig cells was not increased. It was established that glucocorticoid-induced Leydig cell apoptosis is mediated by glucocorticoid receptors (GRs), which translocate from cytoplasm to nucleus. Adenovirus microRNA-induced downregulation of GR expression in vitro alleviated the corticosterone-induced increase in apoptosis of Leydig cells. These results indicate that the stress-induced increase in corticosterone secretion resulted in apoptosis in rat Leydig cells in vivo, and thereby decreased testosterone synthesis. 相似文献
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44.
In this study we clarified the multiple‐level effects of Confucian‐related work values, including self‐discipline and interpersonal ethics, on the performance of individuals and the team. Empirical data of 70 work teams with 472 team members from Taiwanese enterprises were collected to test our hypotheses. Results showed that, at the group level, shared team values of interpersonal ethics were positively related to team performance through the partial mediation of team cooperation. For cross‐level effect, shared team values of interpersonal ethics and individual member's self‐discipline values were both positively related to individual performance. The implications of Confucian dynamism work values on contemporary organizational management and indigenous Chinese team theories were provided. 相似文献
45.
We investigated age-related differences in finger coordination during rotational hand actions. Two hypotheses based on earlier studies were tested: higher safety margins and lower synergy indices were expected in the elderly. Young and elderly subjects held a handle instrumented with five six-component force sensors and performed discrete accurate pronation and supination movements. The weight of the system was counterbalanced with another load. Indices of synergies stabilizing salient performance variables, such as total normal force, total tangential force, moments produced by these forces, and total moment of force were computed at two levels of a hypothetical control hierarchy, at the virtual finger-thumb level and at the individual finger level. At each level, synergy indices reflected the normalized difference between the sum of the variances of elemental variables and variance of their combined output, both computed at comparable phases over repetitive trials. The elderly group performed the task slower and showed lower safety margins for the thumb during the rotation phase. Overall, the synergy indices were not lower in the elderly group. In several cases, these indices were significantly higher in the elderly than in the younger participants. Hence, both main hypotheses have been falsified. We interpret the unexpectedly low safety margins in the elderly as resulting from several factors such as increased force variability, impaired feed-forward control, and the fact that there was no danger of dropping the object. Our results suggest that in some natural tasks, such as the one used in this study, healthy elderly persons show no impairment, as compared to younger persons, in their ability to organize digits into synergies stabilizing salient performance variables. 相似文献
46.
Kim Yin Chan Moon-ho R. Ho Oleksandr S. Chernyshenko Olwen Bedford Marilyn A. Uy David Gomulya Y.L. Sam Wei Ming J. Phan 《Journal of Vocational Behavior》2012,81(1):73-88
We propose a person-centered framework for conceptualizing subjective careers in an increasingly boundaryless work context. Specifically, we argue that entrepreneurship, professionalism, and leadership (EPL) can serve as three key dimensions of subjective career space. We relate this framework to earlier macro-level national and organizational career models proposed by Kanter (1989) and Schein (1978). Our empirical study involving 10,326 Singaporean university students demonstrated that entrepreneurial, professional, and leadership career aspirations (including motivations, efficacies, and intentions) can be measured independently, that these career dimensions are independent of vocational interests, and that they are to some degree viewed as competing career alternatives. We also show that EPL motivation profiles can operationalize the boundaryless and protean career concepts. Individuals concurrently high in entrepreneurial, professional, and leadership career motivations, and those high in entrepreneurial and leadership motivations are highest in boundaryless and self-directed career attitudes, while those primarily motivated for professional careers hold the most traditional career attitudes. We conclude by discussing the potential of the framework for understanding human resource issues at organizational and national levels and for enhancing the study of entrepreneurship, professionalism, and leadership. 相似文献
47.
Yan M Zhou W Shu H Kliegl R 《Journal of experimental psychology. Learning, memory, and cognition》2012,38(4):1069-1075
Semantic processing from parafoveal words is an elusive phenomenon in alphabetic languages, but it has been demonstrated only for a restricted set of noncompound Chinese characters. Using the gaze-contingent boundary paradigm, this experiment examined whether parafoveal lexical and sublexical semantic information was extracted from compound preview characters. Results generalized parafoveal semantic processing to this representative set of Chinese characters and extended the parafoveal processing to radical (sublexical) level semantic information extraction. Implications for notions of parafoveal information extraction during Chinese reading are discussed. 相似文献
48.
Previous studies have found that attention orienting is influenced by the orienting processes of previous trials in a spatial
cueing paradigm. This study mainly investigated whether this sequence effect could happen for a non-predictive arrow cue and
whether it was influenced by the cue-target SOAs in previous and current trials. A significant sequence effect was observed
for arrow cues even when voluntary control was not required, and it was significantly influenced by the SOAs of previous trials.
The present results support the automatic memory check hypothesis and may reflect some temporal characteristics of the memory
mechanism in sequential processes. In addition, contrary to the previous findings, we found an overall response facilitation
following a catch trial, suggesting that the influence of preceding catch trials may be sensitive to experimental contexts. 相似文献
49.
Recent years have seen a surge in accounts motivated by information theory that consider language production to be partially driven by a preference for communicative efficiency. Evidence from discourse production (i.e., production beyond the sentence level) has been argued to suggest that speakers distribute information across discourse so as to hold the conditional per-word entropy associated with each word constant, which would facilitate efficient information transfer (Genzel & Charniak, 2002). This hypothesis implies that the conditional (contextualized) probabilities of linguistic units affect speakers' preferences during production. Here, we extend this work in two ways. First, we explore how preceding cues are integrated into contextualized probabilities, a question which so far has received little to no attention. Specifically, we investigate how a cue's maximal informativity about upcoming words (the cue's effectiveness) decays as a function of the cue's recency. Based on properties of linguistic discourses as well as properties of human memory, we analytically derive a model of cue effectiveness decay and evaluate it against cross-linguistic data from 12 languages. Second, we relate the information theoretic accounts of discourse production to well-established mechanistic (activation-based) accounts: We relate contextualized probability distributions over words to their relative activation in a lexical network given preceding discourse. 相似文献
50.