Determination of a behavioral transfer function: White-noise analysis of session-to-session response-ratio dynamics on concurrent VI VI schedules

Six pigeons were exposed to concurrent variable-interval schedules in which the programmed reinforcer ratios changed from session to session according to a pseudorandom binary sequence. This procedure corresponded to the stochastic identification paradigm (“white-noise experiment”) of systems theory and enabled the relation between log response ratios in the current session and log reinforcer ratios in all previous sessions to be determined. Such dynamic relations are called linear transfer functions. Both nonparametric and parametric representations of these, in the form of “impulse-response functions,” were determined for each bird. The session-to-session response ratios resulting from the session-to-session pseudorandom binary variations in reinforcer ratios were well predicted by the impulse-response functions identified for each pigeon. The impulse-response functions were well fitted by a second-order dynamic model involving only two parameters: a time constant and a gain. The mean time constant was 0.67 sessions, implying that the effects of abrupt changes in log reinforcer ratios should be 96% complete within about five sessions. The mean gain was 0.53, which was surprisingly low inasmuch as it should equal the sensitivity to reinforcement ratio observed under steady-state conditions. The same six pigeons were subjected to a similar experiment 10 months following the first. Despite individual differences in impulse-response functions between birds within each experiment, the impulse-response functions determined from the two experiments were essentially the same.     

The prevalence,risk factors and outcomes of workplace bullying among junior doctors: a systematic review

ABSTRACT

Junior doctors’ exposure to bullying may impact their training and compromise quality healthcare, yet little is known in relation to its predictors and effects. The aim of this paper is to assess the prevalence, factors and outcomes of workplace bullying among junior doctors. Literature search was performed to identify all primary studies examining workplace bullying among junior doctors using the following electronic databases: Medline, Scopus, Web of Science, PsycINFO and Cochrane Library. A total of 18 articles were included, reporting on a total of 9,597 junior doctors. The quality of evidence can be rated as moderate according to the Newcastle Ottawa Scale. From the review, a wide range (30–95%) of bullying prevalence, significant differences in bullying rates according to gender, age, height, ethnicity and subspecialty, and significant associations between bullying and mental strain, job dissatisfaction, burnout, and increased accidents at work were observed. Concurrently, heterogeneity in the terms and methodologies used to examine workplace bullying as well as definitional issues in relation to the persistency of negative interactions were noted. Evidence suggests that workplace bullying is a serious occupational hazard for junior doctors, and more research is warranted to better understand this phenomenon and address its definitional and methodological issues.     

Physicians' Silent Decisions: Because Patient Autonomy Does Not Always Come First

Physicians make some medical decisions without disclosure to their patients. Nondisclosure is possible because these are silent decisions to refrain from screening, diagnostic or therapeutic interventions. Nondisclosure is ethically permissible when the usual presumption that the patient should be involved in decisions is defeated by considerations of clinical utility or patient emotional and physical well-being. Some silent decisions—not all—are ethically justified by this standard. Justified silent decisions are typically dependent on the physician's professional judgment, experience and knowledge, and are not likely to be changed by patient preferences. We condemn the inappropriate exclusion of the patient from the decision-making process. However, if a test or treatment is unlikely to yield a net benefit, disclosure and discussion are at times unnecessary. Appropriate silent decisions are ethically justified by such considerations as patient benefit or economy of time.     

语言伴随性手势是否和语言共享同一交流系统?

语言伴随性手势是人类语言交流的一个普遍的特征, 它可以发挥信息交流的功能。依据产生目的以及适用范围的不同, 手势可以分成表象性手势和非表象性手势。多数研究者认为, 语言和手势动作是“近亲”, 具有“家族相似性”。来自语言发展、认知心理学和认知神经科学的证据均表明, 手势和语言共享同一个交流系统。当手势动作和发音单词意义相同时, 手势动作受到单词发音的干扰, 同时引发发音共振峰2 (F2)的放大。手势和言语之间遵循互相作用理论, 它们作用的基础是语义一致性, 镜像神经系统完成了两者语义一致性的传递。由于语言伴随性手势和语言之间的关系是语言和行为结合良好的特例, 因此, 对语言伴随性手势的研究将有助于对人类心智有一个更深层次的认识和理解。     

3～5岁幼儿在主题-规则冲突条件下的类比推理

本研究采用经典类比任务,考察了3～5岁幼儿在主题-规则冲突条件下类比推理发展的水平与特点.结果表明:(1)在无主题联想条件下,幼儿的单维类比推理在3～4岁迅速发展,4～5岁发展较为平缓,而双维类比推理在3～5岁仍处于较低水平.(2)在主题—规则冲突条件下,幼儿在单维类比推理中表现出一定的主题联想优势反应;幼儿在双维类比推理中表现出较强的主题联想优势反应,年龄特点为:3岁幼儿有较强的主题联想优势反应,4岁幼儿的主题联想优势反应明显下降,而5岁幼儿又表现出较强的主题联想优势反应.     

积极情绪对视觉注意的调节及其机制

在积极心理学思潮的推动下, 已有研究不但发现积极情绪扩展了空间和时间注意范围、增加了注意灵活性, 而且发现在积极情绪下个体对积极刺激表现出了注意偏向。对这些现象, 先前研究主要以积极情绪的扩展与建构理论、情绪信息等价说等理论来加以解释。但这些理论主要从宏观上强调情绪信息对注意加工的启动或积极情绪对注意资源分布的调节, 并不能清楚地揭示积极情绪对注意调节的内在机制。神经生化机制研究发现, 这些现象可能与多巴胺系统对注意控制能力的调节以及积极情绪对初级视觉皮层编码的调节有关。将来研究者可以基于不同的种类的注意选择和注意模型来进一步拓展积极情绪对注意调节的研究, 同时注重对其机制的探讨和理论的整合与创新。     

对称场景中朝向一致性对内在参照系的影响

采用部分场景再认范式研究了对称场景中物体朝向的一致性对内在参照系建立的影响。被试在实验1中沿对称轴方向学习无朝向物体组成的场景; 实验2中沿对称轴方向学习有朝向物体组成的场景; 实验3中沿对称轴与物体朝向方向学习与实验2相同的场景。结果表明：(1)物体朝向一致性影响了对称场景中内在参照方向的选择; (2)无论是否存在观察视点的干扰, 观察者选择对称轴和物体的一致朝向作为内在参照方向的可能性没有显著差异。     

从系统论分析慢性炎症向肿瘤的恶性转化

慢性炎症相关肿瘤疾病,其机制涉及到的不再是个别的基因产物或蛋白分子,也不再是单一的信号通路或代谢途径,而是众多的基因、蛋白质和代谢小分子等各种生物分子构成的复杂的调控网络。这一网络中的相互联系、动态以及突变特性,要求运用系统论的方法来分析。这种分析将拓展临床医生的研究思路,推动对炎症向肿瘤转化本质的认识。     

经导管射频消融术发展史及对医学教育的启示

自20世纪未,经导管射频消融术成功用于治疗快速心律失常,取得了瞩目的成就,本文回顾这一技术的发展史,认为它是理工科和医学高度结合的产物,提出医学教育与科研应该有理工医结合的环境。