A validation study of the Keyboard Personal Computer Style instrument (K-PeCS) for use with children

This study examines a potential instrument for measurement of typing postures of children. This paper describes inter-rater, test-retest reliability and concurrent validity of the Keyboard Personal Computer Style instrument (K-PeCS), an observational measurement of postures and movements during keyboarding, for use with children. Two trained raters independently rated videos of 24 children (aged 7-10 years). Six children returned one week later for identifying test-retest reliability. Concurrent validity was assessed by comparing ratings obtained using the K-PECS to scores from a 3D motion analysis system. Inter-rater reliability was moderate to high for 12 out of 16 items (Kappa: 0.46 to 1.00; correlation coefficients: 0.77-0.95) and test-retest reliability varied across items (Kappa: 0.25 to 0.67; correlation coefficients: r = 0.20 to r = 0.95). Concurrent validity compared favourably across arm pathlength, wrist extension and ulnar deviation. In light of the limitations of other tools the K-PeCS offers a fairly affordable, reliable and valid instrument to address the gap for measurement of typing styles of children, despite the shortcomings of some items. However further research is required to refine the instrument for use in evaluating typing among children.     

Convergent and discriminant validity of three measures of stage of change.

The University of Rhode Island Change Assessment (E. A. McConnaughy, J. O. Prochaska, & W. F. Velicer, 1983), the Stages of Change Readiness and Treatment Eagerness Scale (W. R. Miller & J. S. Tonigan, 1996), and the Readiness to Change Questionnaire (S. Rollnick, N. Heather, R. Gold, & W. Hall, 1992) are commonly used multidimensional measures of stage of change. The authors examined the convergent and discriminant validity of drug-use versions of these 3 measures through multitrait-multimethod analysis in a population of indigent, out-of-treatment drug users (N = 377). Agreement in stage-of-change assignment and the relationship between stage of change and drug-use behaviors were also examined. Confirmatory factor analysis suggests that the Stages of Change Readiness and Treatment Eagerness Scale may have questionable convergent validity with the University of Rhode Island Change Assessment and Readiness to Change Questionnaire. There was moderate agreement in stage assignment. Analysis of behavior did provide some support for the construct validity of the measures. The results suggest that these drug-use stage-of-change measures may not be equivalent. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

M-learning in review： Technology, standard and evaluation

Nowadays E-learning as a form of learning depending on networks and computer devices has been expanding by leaps and bounds. As a special kind of E-learning, M-learning （mobile learning） aims at the use of mobile devices anywhere at anytime by anybody. In this paper, the technologies to develop a M-learning system are deeply analyzed according to the layer model at first. Then, from the view of application, the standardization in M-learning is researched in order to accelerate the development and popularization of M-learning. Finally, quality estimation of M-learning system is discussed from the view of QoE （quality of experiences）. The experience form end-user is the sole effective norm to judge the result of M-learning technology. It is no doubt that technologies, standardization and evaluation will play very important parts in the course of M-leaming development.     

On Error Bounds of Finite Difference Approximations to Partial Differential Equations—Temporal Behavior and Rate of Convergence

This paper considers a family of spatially semi-discrete approximations, including boundary treatments, to hyperbolic and parabolic equations. We derive the dependence of the error-bounds on time as well as on mesh size.     

Effects of ultrasonic waves on carbon dioxide solubility in brine at different pressures and temperatures

The adverse impacts of CO₂ emission on the global warming highlight the importance of carbon capture and storage technology and geological storage of CO₂ under solubility trapping mechanisms. Enhancing the solubility of CO₂ in formation water has always been the focus of research in the area of CO₂ sequestration. Ultrasound techniques are one of the environmentally friendly methods that use high-intensity acoustic waves to improve gas solubility in liquids. Ultrasonic waves can alter the properties of different phases that lead to chemical reactions and provide a means to increase the solubility of CO₂ in connate water. In this study, we investigated the effects of ultrasound on the solubility of CO₂ in connate water under different conditions of pressure, temperature, and salinity. The results showed that the solubility of CO₂ was improved with increasing pressure under ultrasonic effects. However, the solubility of CO₂ was inversely proportional to the increase in brine salinity and temperature. Therefore, it was concluded that the solubility of CO₂ might be enhanced in the presence of ultrasound.