The measurement of executive function at age 3 years: Psychometric properties and criterion validity of a new battery of tasks.

In this study, the authors examined the psychometric properties and criterion validity of a newly developed battery of tasks that were designed to assess executive function (EF) abilities in early childhood. The battery was included in the 36-month assessment of the Family Life Project (FLP), a prospective longitudinal study of 1,292 children oversampled from low-income and African American families. Ninety-one percent of children were able to complete 1 or more of the tasks. Psychometric analyses were used to test the dimensionality of each task, evaluate the item and task properties, test the dimensionality of the task battery, and evaluate the criterion validity of the battery with multi-informant measures of attention-deficit/hyperactivity disorder (ADHD) symptomatology and child performance on two subtests of the Wechsler Preschool and Primary Scale of Intelligence. Results indicated that the tasks were successful in measuring interindividual differences in child EF ability, that task scores were most informative about ability level for children in the low to moderate range of ability, that children's performance across the entire battery was adequately summarized by a single factor, and that individual differences on the EF battery were related to ADHD symptomatology and intelligence in expected ways. Results are discussed with respect to the importance of developing psychometrically sound, scalable instruments that facilitate the measurement of interindividual differences in intraindividual change of EF across the early childhood period. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A study of non-stoichiometry in gallium arsenide by precision lattice parameter measurements

An automatic method of precision lattice parameter measurement, capable of repeated measurement at intervals across single crystals with an accuracy of better than one part in 10⁶, has been applied to gallium arsenide. The technique has been used to compare homogeneity of material grown from the melt with that prepared by vapour and liquid epitaxy, to study material grown from the melt under various pressures of arsenic, and to investigate the effect of heavy doping on the lattice parameter. The technique is shown to provide new and interesting information on defects in gallium arsenide.     

SLUDGE TREATMENT AND DRYING REED BED SYSTEMS IN DENMARK

Sludge Reed beds have been used for dewatering (draining and evapotranspiration) and mineralisation of sludge in Denmark since 1988 when the first sludge processing system was introduced. Sludge from wastewater treatment plants (2,500-125,000 pe) is treated in sludge reed bed systems with 1–18 basins with loading rates of 25–2,200 tonnes dry solids/year for ten years. In 2002, approximately 95 systems were in operation. Dimensioning and design of reed bed systems depends on the sludge production rate, sludge type, quality and regional climate.
The maximum sludge loading rate is approximately 50–60 kg DS/m²/year. Loading cycles are related to the sludge type and the age of the sludge reed systems. The sludge residue will, after approximately ten years of operation, reach an approximate height of 1.2–1.5 metres with dry solids content of 30–40%. Experience has shown that the quality of the final product with respect to heavy metals, hazardous organic compounds and pathogen removal after ten years of treatment make it possible to recycle the biosolids to agriculture as an enhanced treated product.     

A framework for integrated quality improvement

The importance of maintaining and improving quality is well understood in most health care organizations. This work becomes more challenging as internal and external conditions rapidly change. A quality improvement framework was developed to help clinicians and administrators organize intergrated, multifaceted quality programs that have the flexibility necessary for success in today's fast-paced health care environment.     

The effect of video game competition and violence on aggressive behavior: Which characteristic has the greatest influence?

Objective: This study is the first to our knowledge to isolate the effect of video game violence and competitiveness on aggressive behavior. Method: In Pilot Study 1, a violent and nonviolent video game were matched on competitiveness, difficulty, and pace of action, and the effect of each game on aggressive behavior was then compared using an unambiguous measure of aggressive behavior (i.e., the Hot Sauce Paradigm) in Experiment 1. In Pilot Study 2, competitiveness was isolated by matching games on difficulty and pace of action, and systematically controlling for violence. The effect of video game competition on aggressive behavior was then examined in Experiment 2. Results: We found that video game violence was not sufficient to elevate aggressive behavior compared with a nonviolent video game, and that more competitive games produced greater levels of aggressive behavior, irrespective of the amount of violence in the games. Conclusion: It appears that competition, not violence, may be the video game characteristic that has the greatest influence on aggressive behavior. Future research is needed to explore the mechanisms through which video game competitiveness influences aggressive behavior, as well as whether this relation holds in the long-term. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Scalable and Selective β-Hydroxy-α-Amino Acid Synthesis Catalyzed by Promiscuous l-Threonine Transaldolase ObiH

Enzymes from secondary metabolic pathways possess broad potential for the selective synthesis of complex bioactive molecules. However, the practical application of these enzymes for organic synthesis is dependent on the development of efficient, economical, operationally simple, and well-characterized systems for preparative scale reactions. We sought to bridge this knowledge gap for the selective biocatalytic synthesis of β-hydroxy-α-amino acids, which are important synthetic building blocks. To achieve this goal, we demonstrated the ability of ObiH, an l -threonine transaldolase, to achieve selective milligram-scale synthesis of a diverse array of non-standard amino acids (nsAAs) using a scalable whole cell platform. We show how the initial selectivity of the catalyst is high and how the diastereomeric ratio of products decreases at high conversion due to product re-entry into the catalytic cycle. ObiH-catalyzed reactions with a variety of aromatic, aliphatic and heterocyclic aldehydes selectively generated a panel of β-hydroxy-α-amino acids possessing broad functional-group diversity. Furthermore, we demonstrated that ObiH-generated β-hydroxy-α-amino acids could be modified through additional transformations to access important motifs, such as β-chloro-α-amino acids and substituted α-keto acids.