A new stable icosahedral quasicrystal in the Cd-Mg-Dy system

A new stable icosahedral quasicrystal has been found in annealed Cd-Mg-Dy alloys. The composition of the icosahedral phase was determined to be approximately Cd₆₆Mg₂₁Dy₁₃. Powder X-ray and electron diffraction patterns revealed that the phase has a primitive icosahedral lattice with a quasilattice parameter a_R = 0.5634 nm. The electron diffraction study confirmed that the phase has a well ordered primitive icosahedral structure.     

题组项目功能差异（DIF）检验方法的应用探索

篇章形式的阅读测验是一种典型的题组测验,在进行项目功能差异（DIF）检验时需要采用与之匹配的DIF检验方法.基于题组反应模型的DIF检验方法是真正能够处理题组效应的DIF检验方法,能够提供题组中每个项目的DIF效应测量,是题组DIF检验方法中较有理论优势的一种,主要使用的方法是Rasch题组DIF检验方法.该研究将Rasch题组DIF检验方法引入篇章阅读测验的DIF检验中,对某阅读成就测验进行题组DIF检验,结果显示,该测验在内容维度和能力维度的部分子维度上出现了具有显著DIF效应的项目,研究从测验公平的角度对该测验的进一步修改及编制提出了一定的建议.研究中进一步将Rasch题组DIF检验方法与基于传统Rasch模型的DIF检验方法以及变通的题组DIF检验方法的结果进行比较,研究结果体现了进行题组DIF检验的必要性与优越性.研究结果表明,在篇章阅读测验中,能够真正处理题组效应的题组DIF检验方法更加具有理论优势且对于阅读测验的编制与质量的提高具有更重要的意义.     

Mixture Factor Analysis for Approximating a Nonnormally Distributed Continuous Latent Factor With Continuous and Dichotomous Observed Variables

Mixture factor analysis is examined as a means of flexibly estimating nonnormally distributed continuous latent factors in the presence of both continuous and dichotomous observed variables. A simulation study compares mixture factor analysis with normal maximum likelihood (ML) latent factor modeling. Different results emerge for continuous versus dichotomous outcomes. For dichotomous outcomes, normal ML path estimates have bias that worsens as latent factor skew/kurtosis increases and does not diminish as sample size increases, whereas the mixture factor analysis model produces nearly unbiased estimators as sample sizes increase (500 and greater) and offers near nominal coverage probability. For continuous outcome variables, both methods produce factor loading estimates with minimal bias regardless of latent factor skew, but the mixture factor analysis is more efficient. The method is demonstrated using data motivated by a study on youth with cystic fibrosis examining predictors of treatment adherence. In summary, mixture factor analysis provides improvements over normal ML estimation in the presence of skewed/kurtotic latent factors, but due to variability in the estimator relating the latent factor to dichotomous outcomes and computational issues, the improvements were only fully realized, in this study, at larger sample sizes (500 and greater).     

Player–Spectator Discrepancies on Risk Preference during Decision Making

Risk preference during decision making depends not only on the potential risk and profits but also on the roles taken in the current task. Those who perform tasks are more risk-seeking than those who only watch. Given the prominent effect of experiencing the task, the player–spectator discrepancies are supposed to arise in the experiencing phase instead of the choosing phase. In the present study, the authors separated the experiencing role and the choosing role through a stylus maze task in which participants first performed in pairs—one as the player and the other as the spectator—and then chose from two rewarding options for themselves or their partners. The findings show that the experience as players induced a risk-seeking tendency in decision making, which suggests that it was the experiencing role, rather than the choosing role, that caused the difference of risk preference, at least for financially motivated groups and under similar task conditions.     

工作记忆训练的研究述评*

以往研究表明,工作记忆是一个资源有限的系统,但近年来大量研究发现工作记忆成绩可以通过训练提高。工作记忆训练是指针对低容量的个体进行针对存储系统或者中央执行系统各成分的训练,以提升个体工作记忆绩效及影响任务相关脑区的活动。来自认知神经科学的证据在评估工作记忆训练的效果上起到了重要作用。虽然目前该领域的研究已经取得一定的成绩,但是利用工作记忆训练来改善个体的工作记忆在具体的方法、训练成效等问题上还存在一定的争议。     

Motor knowledge is one dimension for concept organization: Further evidence from a Chinese semantic dementia case

Neuropsychological and neuroimaging studies have indicated that motor knowledge is one potential dimension along which concepts are organized. Here we present further direct evidence for the effects of motor knowledge in accounting for categorical patterns across object domains (living vs. nonliving) and grammatical domains (nouns vs. verbs), as well as the integrity of other modality-specific knowledge (e.g., visual). We present a Chinese case, XRK, who suffered from semantic dementia with left temporal lobe atrophy. In naming and comprehension tasks, he performed better at nonliving items than at living items, and better at verbs than at nouns. Critically, multiple regression method revealed that these two categorical effects could be both accounted for by the charade rating, a continuous measurement of the significance of motor knowledge for a concept or a semantic feature. Furthermore, charade rating also predicted his performances on the generation frequency of semantic features of various modalities. These findings consolidate the significance of motor knowledge in conceptual organization and further highlights the interactions between different types of semantic knowledge.     

The default mode network and altered consciousness in epilepsy

The default mode network has been hypothesized based on the observation that specific regions of the brain are consistently activated during the resting state and deactivated during engagement with task. The primary nodes of this network, which typically include the precuneus/posterior cingulate, the medial frontal and lateral parietal cortices, are thought to be involved in introspective and social cognitive functions. Interestingly, this same network has been shown to be selectively impaired during epileptic seizures associated with loss of consciousness. Using a wide range of neuroimaging and electrophysiological modalities, decreased activity in the default mode network has been confirmed during complex partial, generalized tonic-clonic, and absence seizures. In this review we will discuss these three seizure types and will focus on possible mechanisms by which decreased default mode network activity occurs. Although the specific mechanisms of onset and propagation differ considerably across these seizure types, we propose that the resulting loss of consciousness in all three types of seizures is due to active inhibition of subcortical arousal systems that normally maintain default mode network activity in the awake state. Further, we suggest that these findings support a general "network inhibition hypothesis", by which active inhibition of arousal systems by seizures in certain cortical regions leads to cortical deactivation in other cortical areas. This may represent a push-pull mechanism similar to that seen operating between cortical networks under normal conditions.     

土家、苗、侗、藏族高中生学业自我的发展特点及对策

采用问卷法对452名民族地区的土家、苗、侗、藏族高中生的学业自我发展特点进行研究,结果表明：（1）土家、苗、侗、藏族高中生的学业自我均处于中等发展水平,民族差异不显著;（2）土家、苗、侗、藏族高中生学业自我总体上性别差异均不显著;（3）除藏族外,其他三民族高中生学业自我的年级差异均不显著,但在学业自我发展的高峰与低谷期上有所差异;（4）除苗、藏族高中生外,土家族和侗族高中生的学业自我均存在显著的城乡差异,农村高中生的学业自我水平均优于城市高中生的。     

Chinese undergraduates' preferences for altruistic traits in mate selection and personal advertisement: Evidence from Q‐sort technique

Human's preferences for altruistic mates have been confirmed by many researchers. Under the deep influence of Confucianism that authorised more parental control over offspring's mate selection, Chinese people's mating strategies and mate preferences may be different from what the evolutionary psychologists have suggested. This study used the Q‐sort technique to assess the roles of altruistic traits in mate selection and personal advertisement. A total of 200 university students participated in the Q‐sort procedures and were asked to sort 50 traits (among which altruistic traits were mixed) according to their importance when choosing (or advertising to) a long‐term (LT) or a short‐term (ST) mate. Our findings were quite different from prior studies. When Chinese participants chose a mate or advertised themselves to a potential mate, kin altruism was considered to be the most important trait; altruistic traits were more preferred by males than by females and females tended to advertise themselves as more altruistic; preferences for altruistic traits showed no difference between LT and ST mate selections (or between personal advertisement to a LT and a ST mate).     

Loneliness and Suicidal Risk in Young Adults: Does Believing in a Changeable Future Help Minimize Suicidal Risk Among the Lonely?

This study examined loneliness and future orientation as predictors of suicidal risk, namely, depressive symptoms and suicide ideation, in a sample of 228 college students (54 males and 174 females). Results of regression analyses indicated that loneliness was a significant predictor of both indices of suicidal risk. The inclusion of future orientation was found to significantly augment the prediction model of both depressive symptoms and suicide ideation, even after accounting for loneliness. Noteworthy, beyond loneliness and future orientation, the Loneliness × Future Orientation interaction term was found to further augment both prediction models of suicidal risk. Consistent with the notion that future orientation is an important buffer of suicidal risk, among lonely students, those with high future orientation, compared to low future orientation, were found to report significantly lower levels of depressive symptoms and suicide ideation. Some implications of the present findings for studying both risk and protective factors associated with suicidal risk in young adults are discussed.