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In endless facets of physiology, there are points of homeostatic balance, such that too much or too litttle of something can both be deleterious (i.e., an "inverse U" pattern). This is particularly true when considering glucocorticoids (GCs), the adrenals steroid secreted during stress. In the first part of this paper, I review a number of realms in which a paucity and an excess of GCs are both damaging. Some findings are classical (for example, concerning GC effects upon body weight), while some are quite recent and have considerable implications for both physiology and pathophysiology (for example, inverse U's of GC actions in the realm of immunity and neuronal survival). The second part of the review considers the far thornier issue of how such inverse U's of GC actions are generated on a cellular and molecular level. One solution that has evolved, primarily in the hippocampus within the nervous system, involves the presence of two different types of receptors for GCs within the same cells; so long as the two receptors have very different affinities and mediate opposing effects on some cellular endpoint, an inverse U will emerge. The second solution, found in a number of peripheral tissues, involves GCs having opposing effects on the amount of some signal being generated (e.g., an immune cytokine) and the sensitivity of target tissues to that signal; under conditions that appear to be physiologically relevant, inverse U's emerge from this pattern as well. The final section of this review considers the enormous role played by Bruce McEwen in the emergence of this literature. I suggest that while much of this obviously has to do with the facts that have come from his group, another substantial contribution is from his steadying and supportive personality, the veritable embodiment of homeostatic balance.  相似文献   
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This study investigated developmental and sex-related differences in affective decision making, using a two-deck version of Children's Gambling Task administered to 3- and 4-year-old children. The main findings were that 4-year-old children displayed better decision-making performance than 3-year-olds. This effect was independent of developmental changes in inductive reasoning, language, and working memory. There were also sex differences in decision-making performance, which were apparent only in 3-year-old children and favored girls. Moreover, age predicted awareness of task and the correlation between the latter and decision-making performance was significant, but only in 4-year-old children. This study thus indicates that there is a remarkable developmental leap in affective decision making, whose effects are apparent around the age of 4, which according to our results, also marks the age when the correlation of declarative knowledge and decision-making performance becomes significant.  相似文献   
3.
Professors are increasingly encouraged to adopt multiple role relationships with their students. Regardless of professor intent, these relationships carry risks. Left unexamined is whether student–faculty social multiple relationships impact student in-class behaviors. Provocatively, our exploratory study provides empirical support suggesting that when undergraduate students perceive that their professors engage in the multiple faculty–student relationships of friendships, drinking (alcohol) relationships, and sexual partnerships, students report they are more likely to engage in uncivil behaviors in the professor’s classroom. Accordingly, our study provides a backdrop against which to think more substantively about the professorial role and the boundaries that accompany it.  相似文献   
4.
Based on the uses and gratifications perspective, personality was expected to relate to violent video game play frequency and game preferences. Participants completed measures of personality and frequency of violent video game play, and identified their most frequently played video games. Results indicate that individuals higher in openness but lower in agreeableness played violent video games more frequently. In addition, more open and extroverted but less agreeable and neurotic individuals generally preferred to play video games that are more violent. Results suggest personality may be more predictive of violent video game use than traditional media use, though the predictive personality dimensions may be consistent across media types.  相似文献   
5.
Under higher education’s contemporary consumer model, students are treated as customers and professors are encouraged to increase student engagement through more personal out-of-class interactions, often in social settings. In the course of this more personal student-faculty involvement, students inevitably encounter or learn of their professors’ occasional inappropriate or unethical behavior. In the present study, we investigated the impact of 145 American undergraduate Business students’ perceptions of their professors’ inappropriate out-of-class behavior on student beliefs and in-class behavior. Results indicate that student perceptions of professors engaging in inappropriate out-of-class behavior were associated with students viewing these professors as lower in ethical character and reporting a stronger likelihood of attending these professors’ classes under the influence of alcohol and illicit drugs, swearing and using vulgarity in these professors’ class discussions, and showing disregard for these professors’ rules, time, and effort. These relationships held even when student grade satisfaction and professor in-class behavior were accounted for. Our results suggest professors’ behavior outside the classroom may impact students’ behavior inside the classroom, re-igniting dialogue regarding the professorial role and the boundaries on oversight of that role. We offer suggestions as to how higher education may address these concerns without infringing upon professors’ personal freedoms.  相似文献   
6.
An extensive literature demonstrates that glucocorticoids (GCs), the adrenal steroids secreted during stress, can have a broad range of deleterious effects in the brain. The actions occur predominately, but not exclusively, in the hippocampus, a structure rich in corticosteroid receptors and particularly sensitive to GCs. The first half of this review considers three types of GC effects: a) GC-induced atrophy, in which a few weeks' exposure to high GC concentrations or to stress causes reversible atrophy of dendritic processes in the hippocampus; b) GC neurotoxicity where, over the course of months, GC exposure kills hippocampal neurons; c) GC neuroendangerment, in which elevated GC concentrations at the time of a neurological insult such as a stroke or seizure impairs the ability of neurons to survive the insult. The second half considers the rather confusing literature as to the possible mechanisms underlying these deleterious GC actions. Five broad themes are discerned: a) that GCs induce a metabolic vulnerability in neurons due to inhibition of glucose uptake; b) that GCs exacerbate various steps in a damaging cascade of glutamate excess, calcium mobilization and oxygen radical generation. In a review a number of years ago, I concluded that these two components accounted for the deleterious GC effects. Specifically, the energetic vulnerability induced by GCs left neurons metabolically compromised, and less able to carry out the costly task of containing glutamate, calcium and oxygen radicals. More recent work has shown this conclusion to be simplistic, and GC actions are shown to probably involve at least three additional components: c) that GCs impair a variety of neuronal defenses against neurologic insults; d) that GCs disrupt the mobilization of neurotrophins; e) that GCs have a variety of electrophysiological effects which can damage neurons. The relevance of each of those mechanisms to GC-induced atrophy, neurotoxicity and neuroendangerment is considered, as are the likely interactions among them.  相似文献   
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