Tourette syndrome (TS) is one of three separate tic disorders. By definition, children with TS must have at least two motor (movement) tics and one vocal (or sound tic) for at least a year. The other tic disorders are chronic tic disorder (motor or vocal tics, but not both for at least one year) and transient tic disorder (motor and/or vocal tics…

This article uses dyadic latent panel analysis (DLPA) to examine environmental influences on well-being. DLPA requires longitudinal dyadic data. It decomposes the observed variance of both members of a dyad into a trait, state, and an error component. Furthermore, state variance is decomposed into initial and new state variance. Total observed…

Objective: The authors ascertained the amount of training in psychiatric genomics that is provided in North American psychiatric residency programs. Methods: A sample of 217 chief residents in psychiatric residency programs in the United States and Canada were identified by e-mail and surveyed to assess their training in psychiatric genetics and…

Aim: Mutations in the "SLC16A2" gene have been implicated in Allan-Herndon-Dudley syndrome (AHDS), an X-linked learning disability syndrome associated with thyroid function test (TFT) abnormalities. Delayed myelination is a non-specific finding in individuals with learning disability whose genetic basis is often uncertain. The aim of this study…

Throughout this monograph, there has been frequent reference to levels of risk, inference of causation, testing for mediating variables, and the need to consider possible moderating influences. In this chapter, the authors review what is meant by these concepts, and then seek to pull together the findings from the English and Romanian Adoptee…

The material in this module introduces students to some of the mathematical tools used to examine molecular evolution. This topic is standard fare in many mathematical biology or bioinformatics classes, but could also be suitable for classes in linear algebra or probability. While coursework in matrix algebra, Markov processes, Monte Carlo…

Knowledge about the functional status of the frontal cortex in infancy is limited. This study investigated the effects of polymorphisms in four dopamine system genes on performance in a task developed to assess such functioning, the Freeze-Frame task, at 9 months of age. Polymorphisms in the catechol-O-methyltransferase ("COMT") and the…

Variability in achievement across learners is a hallmark of second language (L2) learning, especially in academic-based learning. The Twins Early Development Study (TEDS), based on a large, population-representative sample in the United Kingdom, provides the first opportunity to examine individual differences in second language achievement in a…

In this article, I develop a perspective on learning as multilayered phenomena. I take a socio-genetic approach in order to understand human activity and to show how categories are a fundamental part of learning in a specific type of institutional practice. In the empirical section, student dialogue is analysed in relation to a set of categories…

Purpose: To examine which cognitive, environmental, and speech-language variables predict expressive syntax in boys with fragile X syndrome (FXS), boys with Down syndrome (DS), and typically developing (TD) boys, and whether predictive relationships differed by group. Method: We obtained Index of Productive Syntax ( Scarborough, 1990) scores for…

Probe-level microarray data are usually stored in matrices. Take a given probe set (gene), for example, each row of the matrix corresponds to an array, and each column corresponds to a probe. Often, people summarize each array by the gene expression level. Is one number sufficient to summarize a whole probe set for a specific gene in an array?…

Reinforcers contingent on response variability exert powerful and precise control over levels of variability, from stereotypy to stochasticity. This paper reviews how variability-contingent reinforcers interact with non-contingent, eliciting events to influence the variability of operant responses. Relationships to stimulus control, choice,…

This is a Pittsburgh story. It is about a boy named Michael Charles Metil--a boy that transformed many lives, including the author's. While visiting grandparents over the Christmas holiday in Latrobe, Pennsylvania in 1993, Michael became sick. He was lethargic, vomiting, and had some diarrhea. Little did his parents realize how very sick he was,…

A role for the Notch signalling pathway in the formation of arteriovenous malformations during development has been suggested. However, whether Notch signalling is involved in brain arteriovenous malformations in humans remains unclear. Here, we performed immunohistochemistry on surgically resected brain arteriovenous malformations and found that,…

This report used a population-representative longitudinal twin study with two birth cohorts to explore the association between intelligence and education by understanding how genetic and environmental influences on intelligence moderate genetic and environmental influences on school grades and educational attainment. Nonshared environmental…