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.     

Careers guidance in the knowledge society

In modern society individuals are becoming responsible for their own work allocation. They have to acquire so-called 'actor competences'. They have to learn to form their own identity, to determine a direction and to plan a career. However, the individual's shortage of actor competences confronts him or her with many problems; several institutions risk becoming overburdened by allocation or career problems. As a result, the role of the career counsellor must change from that of a ferryman to that of a pathfinder.     

Spatial compatibility of signal-response position in pointing

Two experiments are reported in which, by means of a pointing task, we studied the stimulus-position effect, i.e. the inverted U-shape form of the reaction-time function in relation to stimulus position in tasks in which stimuli and/or responses are arranged in a horizontal array. The response consisted of aiming the index finger from a central starting point at a target area on a screen. Reaction time was the main dependent variable. The spatial relation between the position of the imperative signal and the position of the response was manipulated by varying the spatial S-R compatibility and physical distance that separated the positions of stimulus and response. The stimulus-position effect was shown to depend on the compatibility of the S-R relation (Exp. 1). In Exp. 2 it was found that the modulation of the stimulus-position effect by spatial compatibility disappeared completely when the distance between the positions of stimulus and response was reduced. None of the experiments revealed that the stimulus position effect depended on signal discriminability, which renders an interpretation of this effect in terms of perceptual processes unlikely. We argue that the attentional model of spatial coding provides the most reasonable explanation of the obtained reaction-time patterns.     

Nine Experts Describe the Essence of Rational-Emotive Therapy While Standing on One Foot

The purpose of this study was to determine the extent of agreement among a panel of rational-emotive therapy (RET) experts about the essence of RET. The panel of experts consisted of the 9 members of The International Training Standards and Review Committee of the Institute for Rational-Emotive Therapy in New York. The question that the experts were asked was an adaptation of a Talmudic story known in Jewish lore as “While Standing on One Foot.” Responses were assigned to either of 2 categories: general cognitive behavior therapy (CBT) or RET-specific. There seems to be a range of responses that capture the essence of RET. A strong case can be made for subsuming many aspects of CBT under RET because much of what is associated with CBT has its origins in RET. The confusion about where RET ends and general CBT begins goes to the very heart of RET's status today.     

Factor structure of the basic personality inventory with incarcerated offenders

The item and scale factor structure of the Basic Personality Inventory (BPI) was examined in a sample of 486 offenders incarcerated for violent and sexual crimes. Separate principal-component analyses of the items for each of the 11 clinical scales, critical item scale, and social desirability scale indicated a one-dimensional factor solution for all scales except Depression and Persecutory Ideation. The Depression scale's two factors were Hopelessness and Depressive Affect and the Persecutory Ideation scale's two factors were General Paranoia and Perception of External Control. Although the factors for these two scales may assist in interpretation, the correlations between the factors and the total score of their respective scale were high. Confirmatory factor analysis of the 220 items from the 11 clinical scales supported the factorial logic of the scoring key. Analysis of the 11 clinical scales resulted in two factors: General Psychopathology/Adjustment and Antisocial Orientation. The results suggest that all but two scales can be viewed as unidimensional thereby allowing for a straightforward clinical interpretation. These analyses support the internal structure of the BPI and lend credence to external validity work with forensic populations.     

S&T indicators for strategic planning and assessment of public research institutions

This article presents an approach we have developed for the assessment of public research institutions in the natural sciences and engineering. The method consists in the exploitation of available S&T databases and indicators, including bibliometrics (databases of scientific as well as technical literature), patents, and internal data. Results are therefore derived through multiple databases. The objective is to profile a specific national R&D community in order to assess the positioning of a public institution or program within the community to which it belongs. It involves obtaining the profile of the evolution of an R&D area, the R&D performers, the financing and support institutions, the users of R&D results, and the interactions between all these actors. A case-study of Canadian research in polymers is presented. Part of this research was financed by the National Research Council of Canada, and by a strategic grant from the Social Sciences and Humanities Research Council. The research benefited from the expertise of Robert Letellier, Robert H. Marchessault, Jacques Martel, and Marielle Piché, and from the technical assistance of Maryse Prud’homme, Marcel Parent, and Benoit Longpré.     

Case vignette: cybertherapy

Dr. Neuro Transmitter, a psychotherapist in Paramus, New Jersey, provides services through an online, real-time consultation service known as CyberShrink, Inc., of Dallas, Texas. He is paid by the hour for his consultation services to subscribers who are billed by credit card through CyberShrink. One afternoon he logs on and is connected via private "chat channel" to a new subscriber to the service. She is Ann Hedonia of Simi Valley, California. Ten minutes into the session, Dr Transmitter recognizes that Ms. Hedonia is seriously depressed with suicidal ideation and is feeling on the edge of her ability to cope. He gently suggests that perhaps she ought to think about hospitalization near her home. Ms. Hedonia replies, "Even you don't care about me! That's it. I'm going to do it!" and disconnects. Discussion questions: Is offering psychotherapy services online ethical? What are Dr. Transmitter's obligations in general and at this particular moment to Ms. Hedonia? Suppose Ms. Hedonia has a complaint about Dr. Transmitter. From whom can she seek a remedy? Which state's laws apply regarding professional practice, confidentiality, or licensing qualifications? Must Dr. Transmitter be licensed in any state to offer this service?     

A comparison of multiple versus single examples of the correct stimulus on task acquisition and generalization by persons with developmental disabilities

In teaching discriminations to persons with retardation, we often presume we will improve acquisition and generalization if we use multiple examples of boththe correct and incorrect stimuli. Two experiments were conducted to test this hypothesis. In the first experiment, 7 persons with moderate retardation learned to discriminate between functional words under two conditions. In one condition, Multiple Example of S- Only,1 example of the correct stimulus (S+) and 10 examples of the incorrect stimulus (S-) were used during acquisition. In the other condition, Multiple Examples of S+ and S-,10 examples of the S+ and 10 examples of the S- were used. Results showed that the condition which presented only a single example of S+ was superior 16 times and inferior 4 times during acquisition, generalization, and maintenance. A second experiment was conducted to (a) replicate the methodology and procedures in Experiment 1 with different participants, (b) determine whether the results were replicable, and (c) obtain efficiency data. Results replicated the findings of the first experiment. The condition which presented only a single example of S+ was superior on measures of (a) trials to criterion, (b) percent correct during acquisition, and (c) minutes to criterion. On measures of generalization, the two conditions were relatively equal. Thus, the condition which presented only a single example of the correct stimulus was more efficient and was just as effective in generalization as the condition which presented multiple examples of both the S+ and S-. These surprising results were discussed in terms of stimulus control, why students performed just as well during generalization when only one example of the S+ was used, why acquisition was also poorer for this condition, and how future studies might address these points.     

Prepulse effects on magnitude estimation of startle-eliciting stimuli and startle responses

The present studies investigated the relationship between prepulse effects on the modification of the brainstem startle reflex and magnitude estimates of startle-eliciting stimuli. In Experiment 1, startle eyeblink responses were elicited in 24 students, half of whom were instructed to estimate the loudness of the startle stimulus (actual intensities of 80, 90, and 100 dB) and half of whom were instructed to estimate the magnitude of their eyeblink. When weak acoustic prepulses preceded the startle-eliciting stimulus, eyeblink amplitude was inhibited, and estimates of response magnitude decreased, but estimates of startle stimulus magnitude decreased only when 100-dB startle stimuli were presented. In Experiment 2, the same startle stimuli were preceded on some trials by a vibrotactile prepulse to the hand. In conditions in which startle amplitude was inhibited, startle stimulus magnitude estimates were not affected. This suggests that the effect of acoustic prepulses on 100-dB startle stimuli in Experiment 1 may have been due to loudness assimilation, an effect independent of the prepulse inhibition of startle responding.