A Bayesian Modeling Approach for Generalized Semiparametric Structural Equation Models

In behavioral, biomedical, and psychological studies, structural equation models (SEMs) have been widely used for assessing relationships between latent variables. Regression-type structural models based on parametric functions are often used for such purposes. In many applications, however, parametric SEMs are not adequate to capture subtle patterns in the functions over the entire range of the predictor variable. A different but equally important limitation of traditional parametric SEMs is that they are not designed to handle mixed data types—continuous, count, ordered, and unordered categorical. This paper develops a generalized semiparametric SEM that is able to handle mixed data types and to simultaneously model different functional relationships among latent variables. A structural equation of the proposed SEM is formulated using a series of unspecified smooth functions. The Bayesian P-splines approach and Markov chain Monte Carlo methods are developed to estimate the smooth functions and the unknown parameters. Moreover, we examine the relative benefits of semiparametric modeling over parametric modeling using a Bayesian model-comparison statistic, called the complete deviance information criterion (DIC). The performance of the developed methodology is evaluated using a simulation study. To illustrate the method, we used a data set derived from the National Longitudinal Survey of Youth.     

双语词汇理解切换中非目标语言加工

实验采用直接语音掩蔽启动范式,通过掩蔽词的有、无呈现对切换后单词的读音判断反应时产生影响,进而了解非熟练双语者双语理解切换中非目标语言加工状态。实验结果表明,无呈现掩蔽词组的反应时比有呈现组的判断反应时长;不同掩蔽词呈现时间两组中切换反应时判断不显著。实验证明无论是哪一种语言作为非目标语言,其在词汇层上均都不会被激活;双语词汇理解切换中,切换至熟练语言比切换至不熟练语言切换代价小。     

英语阅读问题解决的认知诊断

本研究尝试将认知诊断技术应用于中学生英语阅读问题解决(ERPS),以实现对中学生英语阅读问题解决的认知诊断,探讨中学生英语阅读问题解决的认知发展特点及其所存在的问题,为中学生的相关认知发展和知识获取服务。研究发现:(1)基于文本表征和反应决策两个加工过程中的七个认知属性是影响中学生ERPS的主要认知成分(R2=0.792);(2)中学生对于文本表征加工过程所涉及的属性的掌握情况优于反应决策加工过程所涉及的属性,学生所面临的主要困主要难于在反应决策加工阶段;(3)对不同属性掌握情况上存在显著的学校类型差异。(4)学生认知掌握状态的类型主要集中在15种(占73%),最多的三种为(1111011)、(1111110)和(1111101)(占34%)。总体来说,学生的属性掌握还是比较好的。相对地,对推理、信息匹配和正确选项的加工水平三个属性掌握较差,应引起重视。     

HO-DINA模型的MCMC参数估计及模型性能研究

认知诊断目前在国内外越来越受到重视,而要真正实现认知诊断,需借助一定的计量学模型即认知诊断模型。国际上,目前已开发近60种认知诊断模型,不同模型又各具特点。本研究重点分析国外研究较成熟的模型--HO-DINA/DINA模型,具体探讨该模型参数估计的实现及模型性能,采用Monte Carlo模拟方法进行,研究发现：(1)本研究对项目参数、属性参数和被试参数估计返真性较好、稳健性较强、HO-DINA模型具有较高的判断率,MCMC算法可行;（2）诊断的属性个数越多,诊断的模式正确率越低,建议实际使用该模型时,诊断的属性个数不宜超过7个;（3）用于诊断的项目数越多,诊断的模式正确率越高,在实际工作中,若要保证有80%以上的模式判准率,则4个属性的至少需20题,5个、6个和7个属性的至少需要40题,8个属性至少需60题。实际运用者应根据实际情况考虑适当的项目数及属性数。     

数学学习困难初中生的记忆广度特点

记忆广度包括短时记忆广度和工作记忆广度,为揭示数学学习困难学生认知缺损特点,筛选103名初中生（平均年龄12.57岁）,比较数学困难学生（49名）与数学优秀学生（54名）的记忆广度差异,通过词语系列任务、阅读广度任务以及倒背数字任务,分别测查了短时记忆、言语工作记忆以及数字工作记忆。结果发现,数困组与优秀组的学生在词语系列任务中没有显著差异（t＝-1.59, p>.05）,在阅读广度任务中,具有显著差异（t＝-2.38, p<.05）,在倒背数字任务中具有极其显著的差异（t＝-4.69, p<.01）。阅读广度和倒背数字之间具有显著相关(r=.24, p<.05),词语系列任务与阅读广度(r=.19, p>.05)和倒背数字任务(r=.05, p>.05)之间不存在显著相关。研究表明,在具有干扰情况的任务更能有效预测数学成绩,数学学习困难的认知缺损主要是对抗干扰的能力不足,而非简单的短时记忆广度。     

马克思的“个体”和“共同体”概念

个体与共同体的概念在马克思哲学和历史理论中占有重要的地位。"人格个体"(das persoenliche Individuum)与作为这种个体联合的"真正共同体"(wirkliche Gemeinschaft),构成马克思所追求的理想社会的密不可分、互为前提的两端。马克思对个体与共同体及其相互关系的认识和重建,集中反     

Alerting and orienting of attention without visual awareness

Two types of the attentional network, alerting and orienting, help organisms respond to environmental events for survival in the temporal and spatial dimensions, respectively. Here, we applied chromatic flicker beyond the critical fusion frequency to address whether awareness was necessary for activation of the two attentional networks. We found that high-frequency chromatic flicker, despite its failure to reach awareness, produced the alerting and orienting effects, supporting the dissociation between attention and awareness. Furthermore, as the flicker frequency increased, the orienting effect attenuated whereas the alerting effect remained unchanged. According to the systematic decline in temporal frequency sensitivity across the visual hierarchy, this finding suggests that unconscious alerting might be associated with activity in earlier visual areas than unconscious orienting. Since high-frequency flicker has been demonstrated to only activate early visual cortex, we suppose that neural activation in early visual areas might be sufficient to activate the two attentional networks.     

GSK-3β activity in the hippocampus is required for memory retrieval

Several molecules were recently found to be important for the memory retrieval process in the hippocampus; however, the mechanisms underlying the memory retrieval remain poorly understood. GSK-3β has been implicated in the control of synaptic plasticity and memory formation. Here, we investigated the relationship between hippocampal GSK-3β activity and memory retrieval using behavioral and Western blotting methods. We found that GSK-3β was activated in the hippocampus after a retention session in the passive avoidance task. An intrahippocampal injection of the GSK-3β inhibitor, SB 216763, before the retention session blocked memory retrieval (but not reconsolidation) without affecting locomotor activity. These results suggest that GSK-3β activation would be essential for memory retrieval in the hippocampus.