Over the past two decades, researchers consistently demonstrated the importance of science teaching approaches and student self-efficacy in influencing their science achievement. These findings have become the foundation of science education reform. However, empirical supports of these relationships are limited to direct relationships and small-scale studies. Therefore, little is known about the mechanism of how teaching approaches and student self-efficacy affect student achievement. In order to fill these gaps, this study used a multilevel structural equation modeling approach to analyze the direct and indirect relationships between teaching approaches, student self-efficacy, and science achievement by using the data of US eighth grade students in the 2011 TIMSS assessment. The results indicated that none of the teaching approaches identified in this study were directly associated with student science achievement, but significant mediation effect was found between generic teaching and student science achievement through student self-efficacy. Implications of these results for US educational system and reform were discussed.
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
The present study used a Truth Value Judgment Task to investigate whether changes in sentence structure lead to corresponding changes in the assignment of scope relations by Mandarin-speaking children and adults. In one condition, participants were presented with ordinary negative sentences containing disjunction; this condition was designed to verify the existing claim that disjunction is a positive polarity item for adult speakers of Mandarin, but not for child speakers. In a second condition, participants were presented with negative sentences where the disjunction phrase was preposed from object position; this condition was designed to examine the extent to which changes in sentence structure can result in changes in scope assignments to negated disjunctions. The results indicate that the preposed disjunction phrase undergoes reconstruction for children, whereas reconstruction is blocked for adults. This finding also suggests that Mandarin-speaking children and adults exhibit different scope preferences for negated disjunctions, regardless of where the disjunction phrase appears in the surface syntax. 相似文献
We examined whether the broadened attentional scope would affect people's sad or depressed mood with two experiments, enlightened by the meaning of “seeing the big picture” and the broaden‐and‐build model. Experiment 1 (n = 164) is a laboratory‐based experiment, in which we manipulated the attentional scope by showing participants zoomed‐out or zoomed‐in scenes. In Experiment 2 (n = 44), we studied how depressed mood and positive and negative emotions were affected when participants watched distant versus proximal scenes for eight weeks in real life. Healthy participants in Experiment 1, who were induced to feel sad, could return to the baseline mood after having the broadened attention task but not after having the narrowed attention task, which indicated that immediate attention broadening manipulation could function as antidotes for the lingering effects of induced negative emotions. Participants with depressed mood in Experiment 2 showed reduced depressed mood, increased positive affect, and decreased negative affect after receiving attention broadening training compared to those receiving attention narrowing training. Our findings suggest a robust role of broadened attentional scope in relieving negative emotions and even mildly depressed mood in the long run. 相似文献