Multiple hydrogen trapping at monovacancies

Novel structures for multiple hydrogen atoms trapped at a monovacancy are discussed. Using atomistic simulations based on semiempirical interatomic potentials and density functional theory, we find low-energy configurations for four, five, and six hydrogen atoms around a monovacancy different than those that have been previously studied in the literature. The energetics of hydrogen binding are compared to results, both theoretical and experimental, previously published in the literature. We argue that up to four hydrogen atoms may be exothermically bound to monovacancy.     

When does feature search fail to protect against attentional capture?

ABSTRACT

When participants search for a shape (e.g., a circle) among a set of homogenous shapes (e.g., triangles) they are subject to distraction by colour singletons that are more salient than the target. However, when participants search for a shape among heterogeneous shapes, the presence of a non-target colour singleton does not slow responses to the target. Attempts have been made to explain these results from both bottom-up and top-down perspectives. What both accounts have in common is that they do not predict the occurrence of attentional capture on typical feature search displays. Here, we present a case where manipulating selection history, rather than the displays themselves, leads to attentional capture on feature search trials. The ability to map specific colours to the target and distractor appears to be what enables resistance to capture during feature search.     

Voluntary aspects of attentional control setting for detecting a feature‐defined target1

Abstract: Singleton targets that differ from distractors in a single salient attribute can be discerned regardless of the number of items in the display. Recent studies have indicated that the perception of singleton targets is facilitated by an attentional control setting. We focused on the voluntary aspect of the attentional control setting. Psychophysical and functional magnetic resonance imaging (fMRI) experiments examined the temporal characteristics of the attentional control setting by using an auditory cue. In both experiments, an auditorily cued feature‐search task was used. The cue validity (valid vs. neutral) and the cue lead time (CLT) were varied. In the psychophysical experiment, we established the effect of a symbolic cue on detection of a singleton. When the CLT was short or the cue was neutral, there was no facilitation, as re?ected by the slow activation of the attentional control setting. In our fMRI experiment, the brain activity indicates that this detection task activated the prefrontal cortex. These results demonstrate that the attentional control setting for facilitation of the singleton‐target perception modulates activity in regions of the prefrontal cortex.     

Languages for Gestalts of line patterns

Any formal model of visual Gestalt perception requires a language for representing possible perceptual structures of visual stimuli, as well as a decision criterion that selects the actually perceived structure of a stimulus among its possible alternatives. This paper discusses an existing model of visual Gestalt perception that is based on Structural Information Theory. We investigate two factors that determine the representational power of this model: the domain of visual stimuli that can be analyzed, and the class of perceptual structures that can be generated for these stimuli. We show that the representational power of the existing model of Structural Information Theory is limited, and that some of the generated structures are perceptually inadequate. We argue that these limitations do not imply the implausibility of the underlying ideas of Structural Information Theory and introduce alternative models based on the same ideas. For each of these models, the domain of visual stimuli that can be analyzed properly is formally defined. We show that the models are conservative modifications of the original model of Structural Information Theory: for cases that are adequately analyzed in the original model of Structural Information Theory, they yield the same results.     

分散空间注意条件下客体特征一致性对视觉特征错觉性结合的影响

本研究通过设置对空间注意资源的分配实施强行操作的情形下,探讨了主、次作业客体形状一致性和次作业客体间距对乏空间注意区次作业客体颜色、形状特征的检测及对特征错觉性结合的影响。实验结果表明：（１）分散空间注意使次作业区域注意减弱,对客体及其颜色和形状特征的识别均产生明显影响．而且对形状的影响又大于颜色;（２）特征错觉性结合率,主、次作业客体形状一致时比客体形状不一致时明显增大;（３）次作业客体间距对特征错觉性结合率无明显影响,但客体形状一致性和客体间距之间存在明显交互作用．     

Site preference and alloying effect of tungsten in the μ phase of Co7Mo6

The electronic structures of the μ phase of Co₇Mo₆ were investigated by means of first-principles calculation based on the density functional theory. The calculated equilibrium lattice parameters of Co₇Mo₆ are in good agreement with the experimental results. The results of calculation reveal that the addition of tungsten (W) promotes the stability of the μ phase of Co₇Mo₆ and W tends to participate in its formation. Through analysing the calculated electronic structure (partial density of states and charge density difference), it can be noted that a strong interaction exists due to d–d hybridization. Also, the majority of the atoms may contribute their valence electrons to the formation of metallic bonds in binary and ternary systems. Furthermore, the calculated results show that the doped W atom prefers to occupy the Co site in Co₇Mo₆ μ phase.     

Influence of vowel context on the audio‐visual speech perception of voiced stop consonants

The work reported here investigated whether the extent of McGurk effect differs according to the vowel context, and differs when cross‐modal vowels are matched or mismatched in Japanese. Two audio‐visual experiments were conducted to examine the process of audio‐visual phonetic‐feature extraction and integration. The first experiment was designed to compare the extent of the McGurk effect in Japanese in three different vowel contexts. The results indicated that the effect was largest in the /i/ context, moderate in the /a/ context, and almost nonexistent in the /u/ context. This suggests that the occurrence of McGurk effect depends on the characteristics of vowels and the visual cues from their articulation. The second experiment measured the McGurk effect in Japanese with cross‐modal matched and mismatched vowels, and showed that, except with the /u/ sound, the effect was larger when the vowels were matched than when they were mismatched. These results showed, again, that the extent of McGurk effect depends on vowel context and that auditory information processing before phonetic judgment plays an important role in cross‐modal feature integration.     

Robust mean and covariance structure analysis through iteratively reweighted least squares

Robust schemes in regression are adapted to mean and covariance structure analysis, providing an iteratively reweighted least squares approach to robust structural equation modeling. Each case is properly weighted according to its distance, based on first and second order moments, from the structural model. A simple weighting function is adopted because of its flexibility with changing dimensions. The weight matrix is obtained from an adaptive way of using residuals. Test statistic and standard error estimators are given, based on iteratively reweighted least squares. The method reduces to a standard distribution-free methodology if all cases are equally weighted. Examples demonstrate the value of the robust procedure.The authors acknowledge the constructive comments of three referees and the Editor that lead to an improved version of the paper. This work was supported by National Institute on Drug Abuse Grants DA01070 and DA00017 and by the University of North Texas Faculty Research Grant Program.     

关于我国高等师范院校公共课心理学教材整体改革的构想

本文在作者实践基础上,从建设新时期具有我国特色的高师公共课心理学教材的高度,提出四点改革构想:1.在教材体系上,围绕师范生今后“教书”和“育人”工作组织心理学基本内容,形成有机联系的“双主线’结构;2.在教材内容上,突出“三个性”——以强调心理学内容对中学教育实践指导意义的实用性,带动理论阐述上的针对性和实践运用上的可操作性;3.在教材论述上,兼顾师范生的认识规律,采用现象—规律—运用的“三段法”程式;4.在教材编写上,提倡专家、高师公共课心理学教师和中学优秀教师“三结合”原则。