Archive for October, 2009

OpenMx Enters Public Beta Testing

Wednesday, October 7th, 2009

OpenMx entered public beta testing on October 8, 2009. The OpenMx website is now accepting self-registration. Go to the website, register, login, and download the most advanced free and open source Structural Equation Modeling package available. Registration also allows posting access to the OpenSem forums. Let us know what you think!

OpenMx is made possible by a Roadmap Initiative grant from the National Institutes of Health

Issues in Intraindividual Variability: Individual Differences in Equilibria and Dynamics over Multiple Time Scales

Tuesday, October 6th, 2009

Boker, S. M., Molenaar, P., & Nesselroade, J. R. (in press) Issues in Intraindividual Variability: Individual Differences in Equilibria and Dynamics over Multiple Time Scales. Psychology and Aging

This article expands on three methodological issues that address needs required to improve research in intraindividual variability: (1) The need to consider the relationship between the time scale of a process and the time scale of its measurement, (2) The need to first model both the deterministic and the stochastic components of psychological processes at the intraindividual level then at a second level model the variation in these deterministic and stochastic components in samples of individuals, and (3) The need to expand one’s thinking beyond individual differences in variance and covariance of latent variables given measurement invariance in order to consider the opposite possibility: idiosyncratic measurement models with invariance applied to the variance and covariance of latent variables.

The manuscript of this article accepted for publication can be downloaded as a PDF. This article may not exactly replicate the final version published in the APA journal. It is not the copy of record.

Parallel Workflows for Data Driven Structural Equation Modeling in Functional Neuroimaging

Tuesday, October 6th, 2009

Kenny, S., Andric, M., Boker, S. M., Neale, M. C., Wilde, M., & Small, S. L. (2009) Parallel Workflows for Data–Driven Structural Equation Modeling in Functional Neuroimaging. Frontiers in Neuroscience

This article presents a computational framework suitable for a data-driven approach to structural equation modeling (SEM) and describe several workflows for modeling functional magnetic resonance imaging (fMRI) data within this framework. The Computational Neuroscience Applications Research Infrastructure (CNARI) employs a high-level scripting language called Swift, which is capable of spawning hundreds of thousands of simultaneous R processes (R Core Development Team, 2008), consisting of self-contained structural equation models, on a high performance computing system (HPC). These self-contained R processing jobs are data objects generated by OpenMx, a plug-in for R, which can generate a single model object containing the matrices and algebraic information necessary to estimate parameters of the model. With such an infrastructure in place a structural modeler may begin to investigate exhaustive searches of the model space. Specific applications of the infrastructure, statistics related to model fit, and limitations are discussed in relation to exhaustive SEM. In particular, we discuss how workflow management techniques can help to solve large computational problems in neuroimaging.

Frontiers in Neuroscience is an open-access journal, so a PDF of the article can be downloaded for free.

Resilience in Adulthood Comes of Age

Tuesday, October 6th, 2009

Ong, A. D., Bergeman, C. S., & Boker, S. M. (2009) Resilience in Adulthood Comes of Age: Defining Features and Dynamic Conceptions. Journal of Personality. 77:6.

This article begins with a selective review of the broad literature on resilience, giving emphasis to the major approaches, empirical findings, and guiding principles that characterize prior studies. It then summarizes an approach to the phenomenon of resilience and illustrate select parts of previous and ongoing studies of older adults. Findings from this research add to the growing body of empirical evidence suggesting that resilience is a common phenomenon that emerges from the coordinated orchestration of basic human adaptive processes.

This article is previewed on the Journal of Personality website and will appear in the December issue. Unfortunately, Wiley/Blackwell rules would require us to pay at $3,000 fee if we were to either provide a downloadable copy or send a pdf as a response to a reprint request. However, since NIH funded parts of this work, Wiley/Blackwell is required to submit the final published version to pubmed. Hooray for NIH! When the free pubmed version is available, a link to that version will appear here.