Number of Subjects and Time Points Needed for Multilevel Time-Series Analysis: A Simulation Study of Dynamic Structural Equation Modeling

Dynamic structural equation modeling (DSEM) is a novel, intensive longitudinal data (ILD) analysis framework. DSEM models intraindividual changes over time on Level 1 and allows the parameters of these processes to vary across individuals on Level 2 using random effects. DSEM merges time series, structural equation, multilevel, and time-varying effects models. Despite the well-known properties of these analysis areas by themselves, it is unclear how their sample size requirements and recommendations transfer to the DSEM framework. This article presents the results of a simulation study that examines the estimation quality of univariate 2-level autoregressive models of order 1, AR(1), using Bayesian analysis in Mplus Version 8. Three features are varied in the simulations: complexity of the model, number of subjects, and number of time points per subject. Samples with many subjects and few time points are shown to perform substantially better than samples with few subjects and many time points.     

Nullor网络一种新的拓扑分析方法

从节点导纳矩阵出发 ,定义了电压图、电流图 ,把节点导纳矩阵的代数余子式表示为电压图、电流图中完全树的树支导纳乘积之和     

From communication to verbalization: Language practices in kindergarten

Most children attend kindergarten very early in western societies; in fact, they are inserted in different contexts of socialization (family, school and/or other day-care). In what are these contexts of socialization different for linguistic abilities that they contribute to develop? How can the young children adapt themselves to these differences? These questions are discussed considering theoretical interactionnist approaches, and some analyses of communication practices in french kindergarten. Perspectives are released for a discussion on a pedagogy of oral language with young children.     

Comparisons of observed process quality in early child care and education programs in five countries

In this cross-national study, observed process quality in preschool classrooms was compared across five countries—Austria (n = 37), Germany (n=103), Portugal (n=88), Spain (n=80), and the U.S.A. (n=390). Process quality was assessed using the Early Childhood Environment Rating Scale (ECERS) and the Caregiver Interaction Scale (CIS). Both instruments had comparable properties when used in the different countries. A MANOVA found overall ECERS differences between countries, with Austria and Germany scoring higher than Spain, and Austria higher than the U.S.A. CIS Sensitivity scale differences showed Austria and Spain with higher scores than the U.S.A. Tests of homogeneity of variance showed U.S.A. with the highest standard deviations. A discriminant analysis, using countries as groups and ECERS items as criterion variables, revealed differences between countries on two discriminant functions: Personalized Care and Availability and Use of Space and Play Materials. Results are discussed in terms of the early childhood traditions and infrastructures found in the five countries.     

Scientific discovery and topological transitions in collaboration networks

We analyze the advent and development of eight scientific fields from their inception to maturity and map the evolution of their networks of collaboration over time, measured in terms of co-authorship of scientific papers. We show that as a field develops it undergoes a topological transition in its collaboration structure between a small disconnected graph to a much larger network where a giant connected component of collaboration appears. As a result, the number of edges and nodes in the largest component undergoes a transition between a small fraction of the total to a majority of all occurrences. These results relate to many qualitative observations of the evolution of technology and discussions of the “structure of scientific revolutions”. We analyze this qualitative change in network topology in terms of several quantitative graph theoretical measures, such as density, diameter, and relative size of the network's largest component.To analyze examples of scientific discovery we built databases of scientific publications based on keyword and citation searches, for eight fields, spanning experimental and theoretical science, across areas as diverse as physics, biomedical sciences, and materials science. Each of the databases was vetted by field experts and is the result of a bibliometric search constructed to maximize coverage, while minimizing the occurrence of spurious records. In this way we built databases of publications and authors for superstring theory, cosmic strings and other topological defects, cosmological inflation, carbon nanotubes, quantum computing and computation, prions and scrapie, and H5N1 influenza. We also built a database for a classical example of “pathological” science, namely cold fusion. All these fields also vary in size and in their temporal patterns of development, with some showing explosive growth from an original identifiable discovery (e.g. carbon nanotubes) while others are characterized by a slow process of development (e.g. quantum computers and computation).We show that regardless of the detailed nature of their developmental paths, the process of scientific discovery and the rearrangement of the collaboration structure of emergent fields is characterized by a number of universal features, suggesting that the process of discovery and initial formation of a scientific field, characterized by the moments of discovery, invention and subsequent transition into “normal science” may be understood in general terms, as a process of cognitive and social unification out of many initially separate efforts. Pathological fields, seemingly, never undergo this transition, despite hundreds of publications and the involvement of many authors.     

Hierarchical Models of Social Competence in Preschool Children: A Multisite,Multinational Study

The generality of a multilevel factorial model of social competence (SC) for preschool children was tested in a 5‐group, multinational sample (N = 1,540) using confirmatory factor analysis. The model fits the observed data well, and tests constraining paths for measured variables to their respective first‐order factors across samples also fit well. Equivalence of measurement models was found at sample and sex within‐sample levels but not for age within sample. In 2 groups, teachers’ ratings were examined as correlates of SC indicators. Composites of SC indicators were significantly associated with both positive and negative child attributes from the teachers’ ratings. The findings contribute to understanding of both methodological and substantive issues concerning SC in young children.     

Beliefs about knowledge and knowing and multiple‐text comprehension among upper secondary students

Using a sample of 282 Norwegian upper secondary students, we examined whether two dimensions of topic‐specific epistemic beliefs, concerning the certainty of knowledge and the justification for knowing, predicted students' understanding of seven texts representing partly conflicting views on climate change. Text comprehension was measured at three different levels. Topic knowledge and topic interest were included in the analyses as control variables. Hierarchical regression analyses showed that students' beliefs about justification for knowledge positively predicted text comprehension at all three levels. That is, students believing that knowledge claims about climate change should be based on rules of inquiry and the evaluation and integration of multiple information sources did better on the three comprehension measures.     

Engaging young children in collective curriculum design

In this study we investigate how 5-year-old children in Brazil and their teachers collectively design science curriculum. More specifically, we develop an agency|structure dialectic as a framework to describe this collective praxis in which science curriculum may emerge as the result of children–teacher transactions rather than as a result of being predetermined and controlled by the latter. We draw on a cultural-historical approach and on the theory of structure and agency to analyze the events showing the complexity of the activity inside a classroom of very young children by science education standards. Data were collected in the context of a science unit in an early-childhood education program in Belo Horizonte. Our study suggests that (a) throughout the movement of agency|passivity || schema|resources one can observe participative thinking, a form of collective consciousness that arises in and from lived experience; (b) learning is a process in which a group is invested in searching for solutions while they create schemas and rearrange resources to evolve a new structure; and (c) the emergent curriculum is a powerful form of praxis that develops children’s participation from early childhood on.