Dislocations in Bi-Pb-Sr-Ca-Cu-O superconductors

Abstract

Dislocations and dislocation networks in superconducting Bi-Pb-Sr-Ca-Cu-O have been observed by means of TEM, confirming that this compound is a layer structure with low stacking fault energy. On the basal plane, dislocations and dislocation networks dissociate into partial dislocations and partial dislocation networks. However, the dissociation of [010] dislocations is hardly observed, which is related to the structural characteristics of the compound.     

进展期非小细胞肺癌维持治疗进展

化疗在进展期非小细胞肺癌的地位已经确立,现有的方案已经达到“化疗疗效平台”。延长化疗无潜在益处,有什么办法可以保持现有的疗效。为此,提出了维持治疗的概念,维持治疗是指患者在完成标准的几个周期化疗且疾病得到控制后再接受的化疗,架起一二线治疗间的桥梁。带来进一步的临床获益。     

DNA甲基化与衰老的哲学思考

伴随着分子生物学的发展.人类对于衰老的认识从最初的整体动物水平推进到了细胞水平和分子水平,DNA甲基化与衰老的研究也成为生命科学领域研究的热点之一.DNA甲基化与衰老中体现了微观与宏观的哲学思想,在实际的科研及临床工作中掌握科学的哲学思维方法非常重要.     

孕育中的旅游伦理学--近年来西方国家旅游伦理研究述评

旅行和旅游是一项历史悠久的人类活动,旅游活动中的伦理问题的存在也和旅游发展的历史一样久远.二战以后,"大众旅游"经过半个多世纪的高速发展,对自然环境和社会文化的负面影响已经凸显出来,因此,旅游研究便开始关注旅游发展伦理问题;与此同时,应用伦理学研究也开始从不同的角度关注旅游发展这一新领域.     

A multistimulus,portable, and programmable conditioning panel for pigeons

A portable two-response-key conditioning panel for pigeons is described. It can be attached to the subjects’ home cages and allows around-the-clock experimentation. Visual stimuli are presented with light-diode display matrices. Food rewards are dispensed directly onto the stimulus/response keys with separate solenoid dispensers. Several platforms can be simultaneously controlled by a single personal computer with programs written in a simple language adapted for on-line operation. Two experiments exploring the effects of prolonged conditioning sessions upon responding and learning demonstrated the effectiveness of the system. The apparatus is an efficient and inexpensive alternative to a conventional conditioning chamber.     

吸烟:促进还是损害前瞻记忆?

以往研究对吸烟或尼古丁摄入影响前瞻记忆的特点和机制进行了探讨,发现吸烟或尼古丁摄入对前瞻记忆的影响具有双重机制:尼古丁能短暂刺激神经递质释放,并通过促进策略加工提高即时的前瞻记忆表现;但长期来看,吸烟会损伤心脑血管和神经元,降低认知和执行功能的水平,从而持久损害前瞻记忆。将来的研究应在区分前瞻记忆任务类型、尼古丁摄入方式等的基础上,进一步明确吸烟或尼古丁摄入影响前瞻记忆的机制。     

The different roles of category- and feature-specific attentional control settings on attentional enhancement and inhibition

Contingent attentional capture suggests that top-down attentional control settings (ACS) can enhance attentional processing of task-relevant properties and inhibit attentional processing of task-irrelevant properties. However, it remains unclear how ACS operates when a distractor has both task-relevant and task-irrelevant characteristics. In the present study, two lateralized ERP components, N2pc and distractor positivity (Pd), were employed as markers of attentional enhancement and inhibition, respectively. The degree of matching between a distractor and a conjunctively defined target was manipulated to illustrate attentional guidance by category-specific ACS (cACS) and feature-specific ACS (fACS), and the relative position between the distractor and the target was manipulated to isolate the processing of the distractor and the target. Experiment 1 showed that, with a long display duration for searching, a reliable N2pc component was elicited by a distractor that was feature-matched but category-mismatched (C-F+) relative to the target-defined properties, suggesting an enhancing effect of fACS. In contrast, Experiment 2 demonstrated that, with a short display duration, a Pd component was elicited by a distractor that was feature-mismatched but category-matched (C+F-) relative to the target-defined properties, suggesting an inhibitory effect of fACS. Moreover, both attentional enhancement and inhibition were only triggered by fACS but not by cACS. In summary, ACS can enhance target-relevant properties or inhibit target-irrelevant properties in response to the display duration, and fACS affects both enhancement and inhibition more than cACS.