Implementation of approach to compute the Lyapunov characteristic exponents for continuous dynamical systems to higher dimensions

A general method for accurately computing the Lyapunov characteristic exponents (LCEs) of continuous dynamical systems has been developed in [10]. In this paper, this method is extended to implementations on systems of arbitrary dimensions. An accurate implementation of the extension of the method to compute LCEs that uses available numerical techniques is presented for systems of arbitrary dimensions. Previously in [10], the original approach had only been implemented for general systems of up to dimension three. Closed form expressions for the exponential of skew symmetric matrices of order 4 and 5 will be presented. These formulas are used to obtain an accurate and efficient implementation of the method for dynamical systems of dimensions 4 and 5. Numerical examples illustrating the accuracy of the implementations are presented.     

Correlates of adjustment to aging among the young-old and the oldest-old: A comparative analysis

This study aims to compare the correlates of adjustment to aging (AtA) reported by young-old and oldest-old adults and to build two structural models to explore the correlates of AtA for these two age groups. A cross-national study encompassing a community-dwelling sample of 823 older adults aged 65 years and older was undertaken. Several measures were employed to assess AtA, subjective well-being, and sense of coherence. A questionnaire to determine socio-demographic (sex, age, professional and marital status, education, household, adult children, family’s annual income, living setting, and self-reported spirituality), lifestyle and health-related characteristics (perceived health, recent disease, medication, and leisure) was also used. Structural equation modeling was employed to investigate a structural model of AtA, comprising socio-demographic, lifestyle, and health-related variables, as well as SWB and SOC for both groups. Leisure was the most significant correlate of AtA for the young-old (β = .422; p < .001) while self-reported spirituality was the most significant correlate of AtA for the oldest-old (β = .711; p < .001). Significant correlates explain 67.8% and 73.1% of the variability of AtA, respectively. The results presented in this study highlighted different perspectives of AtA, outlined in two structural models, for the groups, and the need of addressing the differences between these, when implementing health care interventions, in particular the relevance of leisure and self-reported spirituality.     

Teachers’ beliefs, instructional behaviors, and students’ engagement in learning from texts with instructional pictures

This study investigated the relations between teachers’ pedagogical beliefs and students’ self-reported engagement in learning from texts with instructional pictures. Participants were the biology, geography, and German teachers of 46 classes (Grades 5-8) and their students. Teachers’ instructional behaviors and students’ engagement in learning from texts with instructional pictures were assessed by means of student ratings. Teachers’ beliefs about using texts with instructional pictures in their teaching were assessed by a self-report questionnaire. Results showed that the more teachers believed that students should be taught clear strategies on how to learn from texts with instructional pictures the more engagement was reported by their students. A multilevel mediation model showed that the association between teachers’ beliefs and students’ self-reported engagement was mediated by teachers’ perceived instructional behavior.     

Behavior Regulation and Early Math and Vocabulary Knowledge in German Preschool Children

Research Findings: Behavior regulation, including paying attention, remembering instructions, and controlling action, contributes to children's successful adaptation to and functioning in preschool and school settings. This study examined the development of behavior regulation in early childhood and its potential contribution to individual differences in children's early knowledge (mathematics and vocabulary). Sixty German preschool children were administered a direct observational measure of behavior regulation, the Head-to-Toes Task, and a standardized test to assess early mathematics and vocabulary. Results revealed significant gains in behavior regulation between of 3 and 4 years of age. Moreover, early gender differences were found, with girls outperforming boys at age 4. Behavior regulation was significantly related to performance on the academic tasks, but the pathways to math and vocabulary knowledge differed. Practice or Policy: Discussion focuses on the role of behavior regulation in early academic achievement.     

Mediation Analysis in a Latent Growth Curve Modeling Framework

This article presents several longitudinal mediation models in the framework of latent growth curve modeling and provides a detailed account of how such models can be constructed. Logical and statistical challenges that might arise when such analyses are conducted are also discussed. Specifically, we discuss how the initial status (intercept) and change (slope) of the putative mediator variable can be appropriately included in the causal chain between the independent and dependent variables in longitudinal mediation models. We further address whether the slope of the dependent variable should be controlled for the dependent variable's intercept to improve the conceptual relevance of the mediation models. The models proposed are illustrated by analyzing a longitudinal data set. We conclude that for certain research questions in developmental science, a multiple mediation model where the dependent variable's slope is controlled for its intercept can be considered an adequate analytical model. However, such models also show several limitations.     

An SEM Approach for the Evaluation of Intervention Effects Using Pre-Post-Post Designs

A directly applicable latent variable modeling procedure for classical item analysis is outlined. The method allows one to point and interval estimate item difficulty, item correlations, and item-total correlations for composites consisting of categorical items. The approach is readily employed in empirical research and as a by-product permits examining the latent structure of tentative versions of multiple-component measuring instruments. The discussed procedure is straightforwardly utilized with the increasingly popular latent variable modeling software Mplus, and is illustrated on a numerical example.     

From Book Culture to Amazon Consumerism: Does the Digitization of the Book Industry Lead to Commercialization?

The book market is one of the last media markets affected by digitization, so the question is whether this market follows the same patterns as other media industries before. Our study analyses if these digitization processes lead to a stronger market orientation thus commercialization of a market that traditionally has been understood as a market of cultural goods. We conduct a market analysis and a survey among authors, publishers and booksellers in Germany and Switzerland to answer this question. Our findings support the notion of an increased market orientation among publishers and booksellers. However, the tendencies towards commercialization cannot be attributed to digitization alone but might happen even without it.     

Football,Masculinities and Health on the Gaza Strip

This analysis is built on two questions: first, what discourses of a masculinity of resistance maintaining a sense of normality under abnormal conditions are drawn from the interviews of the footballers referred to in this article, and second, to what extent is football experienced as and felt to be a ‘free space of health’ for the Gaza players in a context of war and blockade and in relation to the situation before 2007. To answer these questions, the author interviewed, during July 2011, male athletes, coaches and managers in nine football clubs in Khan Younis and Gaza City. She also conducted 18 qualitative interviews during November 2011 with footballers in the two top Gaza leagues in Rafah, Khan Younis, Gaza City and Shati Prison Camp.