A first-principles study of the formation of θ′′ phase in Al–Cu alloys

The θ′′-Al₃Cu phase plays an important role in the precipitation process of Al–Cu alloys. This phase has a sandwich structure—every two {200}_Cu layers are separated by three {200}_Al layers. To analyse the formation mechanism of this structure, the elastic strain energy of the {200}_Cu and {200}_Al layers, and the chemical bonding energy that reflects the interaction between the electrons in Cu and neighbouring Al atoms are calculated and analysed by first-principles calculations, projected density of states and Bader analysis. Our computation results reveal that this sandwich structure is energetically preferred in the competition of elastic strain and chemical bonding energies. To minimise the elastic strain energy of {200}_Al and {200}_Cu layers, the {200}_Cu layers prefer being apart from each other, whereas the chemical bonding energy favours the opposite arrangement because the intermetallic bond between Al and Cu atoms may form through p-d hybridization.     

HO-GDINA模型的EM算法参数估计

Generalized DINA Model(G-DINA)为认知诊断模型提供了一个一般性的理论框架,而高阶诊断模型不仅能描述被试的总体水平,还能描述被试对属性的掌握情况(微观的认知状态)以及被试掌握属性与能力的关系,提供更丰富的信息。如果能把这两者结合起来,可能对实际诊断工作的操作有较大帮助。文章首先对考虑高阶结构的整合性模型——HO-GDINA模型的形式进行讨论,探讨其参数估计EM算法的实现,并用模拟过程对模型的估计精度进行研究,结果验证了HO-GDINA的EM算法的正确性,并且说明该算法对该模型有较高估计精确度。然后用饱和模型在约束条件下的特殊形式HO-DINA模型对"分数减法"这一经典数据进行EM算法参数估计和具体分析,展示了HO-GDINA在实际情况中的具体使用,并与de la Torre之前用MCMC估计算法得到的研究结果做比较,基本一致,进一步表明HO-GDINA模型的参数估计EM算法在实际情境中的特殊形式下仍然适用。     

抑制机制发展研究述评

近年来,抑制机制的发展问题已成为认知心理学界研究的热点问题之一。本文主要从儿童早期抑制发展和抑制机制老化两方面介绍了抑制机制发展研究的新进展,并阐述了目前抑制研究领域中存在的问题和不足之处。     

Likelihood of attending to the color word modulates Stroop interference

Three experiments investigated whether the Stroop color-naming effect is modulated by the likelihood of a color word capturing visual attention. In Experiment 1, a bar or a neutral word was presented at fixation as a color carrier, along with a color word randomly appearing in either an achromatic color (white in the main experiment, gray in a follow-up) or purple. Reduction of the Stroop effect (known as Stroop dilution) occurred when the color word was achromatic but not (or to a lesser extent) when it was in purple. In Experiment 2, the color of the color word remained constant throughout trial blocks, and Stroop dilution was equally evident when the word was always in purple and when it was always in white. In Experiment 3, a color bar was presented as the color carrier with both a color word and a neutral word. In this case, the Stroop effect was larger when the color word appeared in purple, and smaller when the neutral word appeared in purple, than when neither word did. These results imply that the extent to which processing of a color word occurs is determined by the likelihood of the word capturing attention.     

时间性·介入·政治有效性——萨特与加缪的一场世纪争论的启示

萨特和加缪是上世纪法国的两位著名文学家和思想家,同为二战时期地下抵抗运动的生死战友,也是惺惺相惜的文学同道。虽然他们有时同被归属于存在主义阵营,但相互之间仍然存在着巨大的     

The vocational well-being of workers with childhood onset of disability: Life satisfaction and perceived workplace discrimination

Workers with disabilities are understudied, and workers with childhood onset of disability have been excluded from many of the studies on disability and work that do exist. This research compares the effects of childhood and adult onset of disability in a nationally representative sample of workers with disabilities. Educational disruptions due to disability status in childhood are negatively associated with life satisfaction and positively associated with perceived discrimination. Although age is associated with increased life satisfaction and decreased perceptions of discrimination for workers with adult disability onset, age is unrelated to these outcomes for workers with childhood disability onset. Receiving workplace accommodations is positively associated with satisfaction and negatively associated with discrimination for both groups, however, these relationships are stronger in magnitude for the childhood disability onset group. Organizational environments, both in education and in the workplace, play a critical role in the vocational well-being of workers with childhood disability onset.     

Fitts’ law holds for pointing movements under conditions of restricted visual feedback

Fitts’ law robustly predicts the time required to move rapidly to a target. However, it is unclear whether Fitts’ law holds for visually guided actions under visually restricted conditions. We tested whether Fitts’ law applies under various conditions of visual restriction and compared pointing movements in each condition. Ten healthy participants performed four pointing movement tasks under different visual feedback conditions, including full-vision (FV), no-hand-movement (NM), no-target-location (NT), and no-vision (NV) feedback conditions. The movement times (MTs) for each task exhibited highly linear relationships with the index of difficulty (r² > .96). These findings suggest that pointing movements follow Fitts’ law even when visual feedback is restricted or absent. However, the MTs and accuracy of pointing movements decreased for difficult tasks involving visual restriction.     

抗血管生成靶向药物相关性高血压

高血压是抗血管生成靶向药物最常见的副作用之一,其机制和管理受到重视。本文就靶向药物导致高血压的机制进行了探讨,考虑可能与抗血管生成药物的作用靶点有关,即影响了血管内皮生长因子的功能所致;介绍临床如何进行高血压管理并建议在抗血管生成靶向药物使用过程中规范地监测、控制血压,开展相关研究。     

上帝是一种幻觉——评理查德·道金斯《上帝的迷思》

道金斯,当代著名的动物行为学家,自然选择理论的辩手,坚定的无神论者,并为自己拥有彻底的无神论思想而自豪。上帝是否存在?道金斯明确表明:上帝就是一种错觉。无论是宇宙的起源与运行,生命的发生与演变,还是道德的敬畏与维护,心灵的抚慰与激励,诸如此类问题大可不必由宗教来回答或承担。从科学观出发逐一废黜上帝在人类心目中的位置。     

Recruitment of the pre-motor area in human inductive reasoning: An fMRI study

Recent studies indicated that the pre-motor area may be recruited in human higher level cognitive functions, including inductive reasoning. In the present study, a typical task of inductive reasoning, function-finding, was explored using functional MRI. fMRI results showed the significant activation of bilateral pre-motor cortex (BA 6), and its left lateralization. Taking together the previous studies and the present experimental design, we concluded that the left pre-motor cortex in the present study may associate with implicit relation synthesis, while the right pre-motor cortex may reflect spatial information processing involved in arithmetic rules.