Validation of a full body 3-D dynamic linked segment model

In studies related to human movement, linked segment models (LSM's) are often used to quantify forces and torques, generated in body joints. Some LSM's represent only a few body segments. Others, for instance used in studies on the control of whole body movements, include all body segments. As a consequence of the complexity of 3-dimensional (3-D) analyses, most LSM's are restricted to one plane of motion. However, in asymmetric movements this may result in a loss of relevant information. The aim of the current study was to develop and validate a 3-D LSM including all body segments. Braces with markers, attached to all body segments, were used to record the body movements. The validation of the model was accomplished by comparing the measured with the estimated ground reaction force and by comparing the torques at the lumbo-sacral joint that resulted from a bottom-up and a top-down mechanical analysis. For both comparisons, reasonable to good agreement was found. Sources of error that could not be analysed this way, were subjected to an additional sensitivity analysis. It was concluded that the internal validity of the current model is quite satisfactory.     

Chronic sorrow: A content analysis of parental differences

Sixty-eight mothers and 64 fathers of children with a neural tube defect responded to a questionnaire about chronic sorrow. Mothers reported a mood state change in very intense category from more pessimistic at time of diagnosis to more optimistic at current time. Fathers, although indicating a mood change in the very intense category to more optimistic, also had more pessimistic responses. Parental similarities and differences were also reported in both times and events that triggered the sorrow response. Categories across times and events were primarily related to health care, school/development concerns and social significance. Clinical and research implications of these findings are discussed.     

Depression and coping in candidates for kidney transplantation: Racial and ethnic differences

Subjects were 288 adolescents and adults with end-stage renal disease who were candidates for kidney transplantation, a group identified at risk for noncompliance. The purpose was to examine racial and ethnic variations in coping—variables that may underlie noncompliance and impact upon health outcome. Secondarily, the relationship between depression and particular styles of coping was investigated. Race/Ethnicity was divided into three categories: Black/Non-Hispanic, White/Non-Hispanic, and Hispanic. Coping and depression were assessed using the COPE and Beck Depression Inventory, respectively. Results indicated that Hispanic and Black subjects were more likely to use maladaptive styles of coping and less likely to use adaptive coping than were White subjects and that Black subjects reported more physical symptoms of depression. These findings point to possible mechanisms underlying the occurrence of noncompliance and resulting poorer health outcome for individuals of different racial and ethnic groups.     

Change in goals and values of men and women from early to mature adulthood

Changes in goals and values between early and middle adulthood were investigated using a longitudinal sample of women and their male partners. Measures designed to assess personality changes as described by Gutmann and Jung were coded from open-ended responses to questions about middle-aged subjects' concurrent and recollected goals and values. The findings indicated that both women and men declined in gender-traditional goals and values and increased in individual goals and values. Archival data for women showed that recollections were accurate and that both cohort and personality factors were related to the extent to which individuals' goals and values changed over time.     

Attentiveness of mothers and fathers to their baby's cries

Thirty-two mother-father-infant triads participated in a study to examine whether parents' responsiveness to their own infant's distress was affected by the infant's birth order and gender. After separating from their 10- to 11-month-old baby, one parent from each family (16 mothers and 16 fathers) was selected to hear cries that were attributed to the child. Consistent with previous findings regarding physiological reactions to crying and observations of caretaking behavior, first-time parents gave quicker and more frequent attention to their infants than did multiporous parents. Speedy intervention was related to the amount of caretaking responsibilities that parents reported they assumed and to the age at which parents believed that their infant first recognized them. The results demonstrate the importance of caretaking for promoting parental sensitivity to infant signals.     

On optimal smoothing and derivative estimation from noisy displacement data in biomechanics

Estimating derivatives from noisy displacement data is a notoriously ill-posed problem in signal processing and biomechanics. Following the work of Wood and Jennings (1978) and Hatze (1979, 1981), the present paper describes the use of optimally regularized, natural quintic splines for estimating smoothed positions, velocities, and accelerations from equidistantly sampled, noisy position measurements. It appears that the nature of the boundary conditions of the data is of some importance, since various algorithms used hitherto result in artefacts throughout the data if the true derivatives at the record ends differ significantly from zero. Natural quintic splines do not suffer from this disadvantage below the third derivative.The ill-posed character of movement analysis has some interesting implications for movement synthesis and optimization, similar to the indeterminacy of muscular co-contraction from merely external, biomechanical measurements.     

The web of work for technical and managerial employees

This study examines aspects of the job and off-job lives of technical and managerial employees. A framework for studying parallel dimensions in these two life spheres is developed. Variables include alienation—powerlessness and meaninglessness—and activities—variety, control, social interaction, and purpose. Findings show strong interaction between alienation from work and that experienced from life off the job. Limited relationships between activity dimensions were found. Overall, results suggest that employees' feelings of alienation carry over strongly between the two life spheres but that only limited carry-over occurs between job activities and those away from work. Findings give no support to the compensatory view of relationships between employees' job and off-job lives.