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.     

Mid-career change in academia: The decision to become an administrator

This study explored the reasons why professors would leave their teaching/ research occupations to begin new careers as administrators. Valence-Instrumentality-Expectancy theory of occupational preference and choice was used as a framework to examine mid-career change among professors and department chairmen at a major university. Data showed that professors' intentions to change careers and become administrators could be explained by the theory. Analyses of job characteristics demonstrated that professors who want a mid-career change are primarily attracted by the power and formal authority vested in the administrative position, while professors who prefer to remain in their career paths do so because of the autonomy it offers.     

Beyond subitizing: Is estimation of numerousness a continuous process?

Evidence is presented for the existence of two forms of estimation of numerousness — in addition to subitizing. In the experiment reported here, horizontal rows of 5–8 black dots were subitized, while estimation of 33–89 differed from 10–33 in the structure of intercorrelations between estimates. A three-dimensional space generated by Smallest Space Analysis produced three subsets of intercorrelations among percent absolute errors in estimating dots: 5–8 dots, 10–21 dots, and 33–89 dots.     

A note on analyzing ordered alternatives

A general method of devising stepwise multiple testing procedures with fixed experimentwise error is applied to the problem of non-parametric randomized block design with ordered alternatives. In addition, the method is applied to other models with ordered alternatives.The author wishes to thank the referees for helpful suggestions.     

Electromyographic indications of laryngeal-area activity during stuttering expectancy

Using surface electrodes, mean microvolt values of laryngeal-area muscle activity were determined for 13 male and 6 female stutterers during 10-sec periods in which single words were silently read and stuttering expectancy was indicated. No significant differences in levels of laryngeal-area muscle activity were found between periods of fluency expectancy and stuttering expectancy preceding both fluent and stuttered speech. The results were interpreted as being nonsupportive of the hypothesis that a breakdown in stutterers' laryngeal-area muscle activity occurs during moments of stuttering expectancy. In addition, the results suggest that the most common rationale for the utilization of laryngeal biofeedback procedures to enhance fluency should be questioned.     

Experiential and physiological responses associated with anger and aggression in women and men

In a 2 × 2 × 2 factorial design, 48 male and female college students were either given a “sex-appropriate” provocation or were not provoked. Half of the subjects were then requested to give a “stream of consciousness” (SOC) report. Throughout the experiment, three physiological measures were monitored. Finally, all subjects delivered noxious sounds to their same-sex partner as part of a Buss-type learning task. No sex differences were found for subjects not giving the SOC report; provoked men and women were equally angry, hostile toward their partner, and displayed equal amounts of aggressive behavior. Provoked men reporting on their SOC, however, appeared to stimulate themselves to more aggression, whereas women seemed to adopt a nonhostile strategy for coping with their anger, thus reducing their inclination to behave aggressively. These patterns of results were closely paralleled by physiological changes. The relative validity of systolic and diastolic blood pressure as indicators of anger arousal was also discussed.     

The universal nature of human intelligence: Evidence from games

Mentally retarded individuals have relatively greater difficulty in dealing with strategic games and puzzles than with many other tasks. Consequently, it is of interest to find that strategic games have been played since ancient times, are played throughout the world, and that players who excel are frequently considered wise. Hidden within the more obvious differences between cultures, strategic games are an invariant expression of certain universal intellectual traits.     

An ethical dilemma: Information control in cancer care

Cancer is a group of diseases that are complicated by various treatment choices available. Information exchange between a patient and physician is critical in helping people to understand what is happening to them and what options for therapy are recommended and available. When information is not exchanged, information control by one or both of the participants occurs. Information needs to be taken into account by both health care professional and patients in making decisions during the crucial phases of care. The phases of care presented are a diagnosis, treatment, the decision, and a recurrence. Factors that influence effective information exchange among patient-provider systems are discussed.     

Children’s use of phonological encoding when reading for meaning

The role of phonological recoding in children’s reading was investigated by means of a task requiring comprehension of sentence meaning: The child’s task was to decide whether a sequence of printed letter strings was a meaningful sentence or not. Meaningless sentences that are meaningful when phonologically recoded (e.g., “He ran threw the street”) produced more incorrect responses than did meaningless sentences that remain meaningless when phonologically recoded (e.g., “He ran sew the street”). The difference in error rates between the two sentence types diminished as a function of age. Control experiments showed that these results were not due to visual similarity effects, nor to imperfect ability to spell homophones. It was concluded that very young readers rely extensively on phonological recoding when reading for meaning; as they grow older, reliance on visual encoding becomes progressively more important.