Unimanual and bimanual continuous movements benefit from visual instructions in persons with down syndrome

ABSTRACT The authors' aim was to understand how persons with Down syndrome (DS) perform different tasks and to assess if there were any differences in performance based on the type of instructions. This is important because of neurological differences in persons with DS and neurological demands for performing different types of tasks. Twenty right-handed participants with DS, 20 chronological age-matched (CA), and 20 mental age-matched (MA) performed unimanual, bimanual, discrete, and continuous drumming following visual, auditory, and verbal instructions. Overall, discrete drumming was performed with shorter movement times than continuous drumming and unimanual drumming was performed with shorter movement amplitude than bimanual drumming. With respect to instructions, persons with DS performed with smaller amplitudes, thus more efficient movements, following the visual instructions than auditory and verbal instructions for all types of tasks, whereas CA performed similarly with all instructions and MA performed with smaller amplitudes with visual instructions than auditory instructions. These results suggest that visual instruction provides the best information for people with DS to aid in performance of many different types of movements.     

Structural equation modeling with small sample sizes using two-stage ridge least-squares estimation

In covariance structure analysis, two-stage least-squares (2SLS) estimation has been recommended for use over maximum likelihood estimation when model misspecification is suspected. However, 2SLS often fails to provide stable and accurate solutions, particularly for structural equation models with small samples. To address this issue, a regularized extension of 2SLS is proposed that integrates a ridge type of regularization into 2SLS, thereby enabling the method to effectively handle the small-sample-size problem. Results are then reported of a Monte Carlo study conducted to evaluate the performance of the proposed method, as compared to its nonregularized counterpart. Finally, an application is presented that demonstrates the empirical usefulness of the proposed method.     

Amotivation and the occupational decision: an investigation of Australian senior high school students

This exploratory study investigated the occupational decision-related processes of senior high school students, in terms of the extent to which they may be amotivated in choosing a future occupation. Data were gathered using a newly developed questionnaire, which was largely adapted from a number of psychometrically proven instruments, and administered to 492 Grade 11 students attending a stratified random sample of six independent high schools in Sydney, Australia. Structural equation modelling was used to analyse the data. The major findings of the study include the development of a new empirically supported model that relates amotivation and vocational decision-related processes. The findings may be used by career advisors, psychologists, educators, and family members to advise and assist amotivated senior high school students to make occupational decisions.     

Belonging – Lucinda Mosher

Book reviewed:
Belonging , Lucinda Mosher, Church Publishing 2005 (1-59627-010-1), 186 pp., pb $15.00     

Identifying two potential mechanisms for changes in alcohol use among college-attending and non-college-attending emerging adults

This study tested whether pro-alcohol peer influences and prosocial involvement account for increases in drinking during the transition into emerging adulthood and whether these mechanisms differ depending on college attendance and/or moving away from home. The authors used structural equation modeling of prospective data from 825 young men and women. For 4 groups defined by college and residential status, more drinking in the spring of 12th grade predicted more pro-alcohol peer influences the following fall, and more pro-alcohol peer influences in the fall predicted increases in drinking the following spring. Going to college while living at home was a protective factor against increases in drinking and selection of pro-alcohol peer involvements. Prosocial involvement (measured by involvement in religious activities and volunteer work) was not significantly related to post-high school drinking except among college students living away from home. Prevention efforts should focus on (a) reducing opportunities for heavy drinking for college and noncollege emerging adults as they leave home and (b) increasing prosocial involvement among college students not living at home.     

Positive Coping among Wives of Male Christian Clergy

Clergy spouses experience various life stressors, yet many cope and function effectively in the midst of their daily challenges. Mental health professionals were asked to identify wives of male clergy who exemplify emotional and spiritual health. Nominees were contacted and interviews conducted with 25 women. Each interviewee was asked about coping with normal life stressors, stressors associated with being married to a minister, and catastrophic life events. All interviews were transcribed and coded, using grounded theory. Participants emphasized the importance of spirituality, social support, limit-setting, and healthy lifestyle choices. Implications are discussed.

The effect of light color on muscular strength and power

The purpose of this study was to assess the effect of the color of light in a room on muscular strength and power. A convenience sample of 18 men (M age = 20.4 yr., SD = 1.2) performed a modified Wingate Anaerobic Cycle Test for muscular power and a hand grip strength test in each of the following conditions: red, blue, and white (neutral) ambient light. A repeated-measures multivariate analysis of variance indicated that average muscular power was significantly higher when performing the test in the room with red light compared to rooms lit with blue light or white light. The results also indicated that grip strength was significantly higher in the room lit with white light as compared to the room lit with blue light.     

Regularized Partial and/or Constrained Redundancy Analysis

Methods of incorporating a ridge type of regularization into partial redundancy analysis (PRA), constrained redundancy analysis (CRA), and partial and constrained redundancy analysis (PCRA) were discussed. The usefulness of ridge estimation in reducing mean square error (MSE) has been recognized in multiple regression analysis for some time, especially when predictor variables are nearly collinear, and the ordinary least squares estimator is poorly determined. The ridge estimation method was extended to PRA, CRA, and PCRA, where the reduced rank ridge estimates of regression coefficients were obtained by minimizing the ridge least squares criterion. It was shown that in all cases they could be obtained in closed form for a fixed value of ridge parameter. An optimal value of the ridge parameter is found by G-fold cross validation. Illustrative examples were given to demonstrate the usefulness of the method in practical data analysis situations. We thank Jim Ramsay for his insightful comments on an earlier draft of this paper. The work reported in this paper is supported by Grants 10630 from the Natural Sciences and Engineering Research Council of Canada to the first author.