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M H Huang S S Hull R D Foreman R Lazzara S Wolf 《Integrative Physiological and Behavioral Science》1992,27(1):6-12
The shortening of the QT interval of the electrocardiogram coincident with acceleration of heart rate and vice versa has been accepted for many years as evidence that the action potential duration and hence QT are necessarily dependent on heart rate. Exceptions to this rule have been attributed to the intervention of counteracting autonomic effects. In order to test this assumption, 26 conscious dogs divided into three groups were tested during baroreceptor stimulation by a bolus injection of phenylephrine. Seventeen dogs had been used in earlier studies in which they had undergone an experimental anterior myocardial infarction with apparent full recovery. A group of those dogs underwent beta-adrenergic blockade by intravenous atenolol 30 min prior to the baroreceptor activation. To test the intactness of the baroreceptor responses in the previously infarcted dogs, a third group of nine dogs that had had no prior myocardial infarction was included. All dogs were adapted to the laboratory environment and were not sedated during experiments. Simultaneous recordings of RR, QT interval, and phasic arterial pressure were made in all dogs before and during baroreceptor stimulation. In the normal group, and the previously infarcted group that received no atenolol, baroreceptor stimulation elicited a small (8/msec), but significant prolongation of the QT associated with a nearly 50% reduction in heart rate. The QT interval of the atenolol-treated dogs, although significantly more prolonged before stimulation, remained unchanged during the reflex. The data indicate that withdrawal of ventricular sympathetic tone may prolong the QT interval, thereby confirming the role of sympathetic innervation in the control of QT.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Fang Cui Kexin Deng Jie Liu Xiaoxuan Huang Jiamiao Yang Yue-jia Luo Chunliang Feng Ruolei Gu 《British journal of psychology (London, England : 1953)》2023,114(4):778-796
Previous studies examining the relationship between ingroup bias and resource scarcity have produced heterogeneous findings, possibly due to their focus on the allocation of positive resources (e.g. money). This study aims to investigate whether ingroup bias would be amplified or eliminated when perceived survival resources for counteracting negative stimuli are scarce. For this purpose, we exposed the participants and another confederate of the experimenters (ingroup/outgroup member) to a potential threat of unpleasant noise. Participants received some ‘relieving resources’ to counteract noise administration, the amount of which may or may not be enough for them and the confederate in different conditions (i.e. abundance vs. scarcity). First, a behavioural experiment demonstrated that intergroup discrimination manifested only in the scarcity condition; in contrast, the participants allocated similar amounts of resource to ingroup and outgroup members in the abundance condition, indicating a context-dependent allocation strategy. This behavioural pattern was replicated in a follow-up neuroimaging experiment, which further revealed that when contrasting scarcity with abundance, there was higher activation in the anterior cingulate cortex (ACC) as well as stronger functional connectivity of the ACC with the empathy network (including the temporoparietal junction and medial prefrontal cortex) for ingroup compared to outgroup members. We suggest that ACC activation reflects the mentalizing process toward ingroup over outgroup members in the scarcity condition. Finally, the ACC activation level significantly predicted the influence of resource scarcity on ingroup bias in hypothetical real-life situations according to a follow-up examination. 相似文献
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Considering the growing acceptance of humanoid robots in the service industry, this study aimed to examine their negative impact on service evaluation, as well as the underlying mechanism of perceived effort and the moderating role of consumer mindset. Three experiments that used different service scenarios revealed that humanoid service robots negatively affected service evaluation compared to human employees, and this effect was mediated by decreased perceived effort. Furthermore, this negative impact was attenuated when consumers had a concrete mindset compared to abstract. This work contributes to both consumer service and robot literature by elaborating on the possible adverse influence of replacing human employees with humanoid service robots. It also offers managerial implications for how and when to adopt a robot service in this machine age. 相似文献
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Rodger Beehler 《Studies in Philosophy and Education》1990,10(4):315-335
The essay examines the argument advanced by E.D. Hirsch, Jr., for instituting ‘cultural literacy’ as a fundamental priority of schools. A number of confusions and equivocations in Hirsch's reasoning are identified, and the propensity of his project to indoctrinate is exposed. Among the features of Hirsch's argument shown to be troubling are his shifting construal of ‘language’, his inconsistency about the requirements of cultural literacy, and his uncritical relation to traditional images of the American past and present. The upshot is to raise the question why Hirsch's project has elicited wide support and praise. 相似文献
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时序信息的加工:自动还是控制 总被引:4,自引:1,他引:3
从长时记忆的角度出发,以故事的形式为实验材料,对时序信息的加工方式和通道效应进行了研究。结果表明,时序信息的加工存在视听通道效应,通道效应的机制源于记忆,且与加工方式有关。时序信息三个属性的加工方式不同:顺序属性倾向于自动加工;位置属性,就视觉信息来说倾问于自动加工,听觉在有顺序标码情况下倾向于自动加工、而在无顺序标码情况下则是一控制加工过程;间隔特性是一个控制加工过程。 相似文献
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分时距认知特点的研究 总被引:6,自引:1,他引:5
本研究探讨了分时距估计的认知特点,检验了SS模型、PT模型和CS模型的预测效度,结果表明:分时距估计主要是在信息提取阶段采用分段推算策略对时间信息进行重建的过程,变化/分割和注意分配对分时距估计有显著影响;SS模型的预测效度最低,PT、CS模型的预测效度较高。 相似文献
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大学生解决物理问题的表征层次的实验研究 总被引:12,自引:1,他引:11
设计了两个实验,探讨优、差生物理问题表征层次的特点。结果表明,优、差生物理问题表征层次有差异。优生侧重于科学理论表征,表现为以物理原理分类,在科学理论表征层次上多为正向推理:差生则受初始表征的影响,以表面特征分类,在科学理论表征层次上多为逆向推理。 相似文献