Cycling on rollers: influence of tyre pressure and cross section on power requirements

The resistance against a cyclist while riding on rollers is due mainly to rolling resistance produced by the deformation of the tyre as it rolls against small diameter drums. Resistance is then combined with wheel speed to set power output. The effect of tyre pressure and cross-section on power was investigated by systematically altering the pressure (552 kPa, 690 kPa, and 827 KPa) in a 20c, 23c, 25c, and 28c tyre of the same design while riding at a wheel speed of 45 kph. Average power over 1 minute was measured with a Power Tap Hub (Tune Corporation, Cambridge, Massachusetts, USA) on five occasions. Statistical significance was evaluated at p < 0.05. Power requirements increased significantly with each reduction in tyre pressure for all tyres and pressures except the 25c between 690 and 827 kPa. The 20c tyre required significantly more power from the cyclist at each tested tyre pressure when compared to the other tyres (which were not different from each other). The differences in resistance from tyre size were not observed when ridden on the road. Additionally, a slightly different tyre design from the same manufacturer responded similarly in the 20c, but was significantly different in the 23c size. It was also observed that power requirements increased significantly when both the wheels were ridden on the rollers as compared to just the rear wheel. These results indicate that the power requirements may be significantly altered by the cyclist by adjusting tyre pressure, tyre cross-section size, tyre type, and with the number of wheels contacting the rollers. However, the magnitude of these power requirements may not be suitable for intense workouts of trained cyclists.     

Evolution of a veterinary medical library.

Planning a new library and developing a book and journal collection for the College of Veterinary Medicine at Iowa State University are described. The Veterinary Medical Library is a self-contained unit (6,800 square feet) for print material within the Veterinary Medical Building. Seating for 140 patrons is available. The collection is designed to provide basic materials for teaching and research in veterinary and comparative medicine. Indexing and abstracting tools permit access to local, state, and national resources as well. At present the collection totals over 17,000 volumes and over 500 serial titles. A working collection of 25,000 volumes will be maintained in the Veterinary Medical Library, and the University Library will continue to function as the principal backup source.     

Validity of a portable force platform for assessing biomechanical parameters in three different tasks

The aim of this study was to determine the precision and accuracy of the vertical and anterior–posterior force components of the portable PASCO PS-2142 force plate. Impulse, peak force, and time to peak force were assessed and compared to a gold standard force plate in three different tasks: vertical jump, forward jump, and sprint start. Two healthy male participants performed ten trials for each task, resulting in 60 trials. Data analyses revealed good precision and accuracy for the vertical component of the portable force plate, with relative bias and root mean square (RMS) error values nearly the same in all tasks for the impulse, time to peak force, and peak force parameters. Precision and accuracy of the anterior–posterior component were lower for the impulse and time to peak force, with relative bias and RMS error values nearly the same between tasks. Despite the lower precision and accuracy of the anterior–posterior component of the portable force plate, these errors were systematic, reflecting a good repeatability of the measure. In addition, all variables presented good agreement between the portable and gold standard platforms. Our results provide a good perspective for using the aforementioned portable force plate in sports and clinical biomechanics.     

Variables associated with disrupted placement in a select sample of abused and neglected children

The purpose of this study was to examine the placement history of 172 abused and/or neglected children who had been placed in a residential home for maltreated children. Data were collected on the child's placement history (i.e., number of placements, time in transition, and placement rate) and also on child and family characteristics. Pearson correlation coefficients were run between child and family variables and each of the three placement history variables. In addition, t-tests were also used as a method of analysis. Results indicated that children with the following characteristics or life circumstances experienced the more disruptive experience while in foster care: children having severe behavior problems; children who were very young when first removed from their natural home; and children having drug addicted and/or alcoholic parents. Implications of these findings indicate social workers and judges need to be alert to the potential for system abuse of children in foster placement, responsible long-term planning for any child in foster care is critical, and those involved in therapeutic treatment for abused/neglected children should be attentive to the child's placement history.     

Judgments Regarding Appropriate Child Supervision to Prevent Injury: The Role of Environmental Risk and Child Age

Parents, social service workers, and medical personnel failed to differ in the amount of time they estimated that children of 11 differing ages should be left without adult supervision within 5 different supervision domains. More hazardous circumstances dramatically reduced the amount of time respondents said children should be left unsupervised. Amount of unsupervised time increased with age, with clear developmental cutoffs that varied by level and type of risk. When the moderate center of the distribution was examined, 3 clear areas of consensus emerged. For most domains, constant supervision was recommended for preschool children. For early elementary school children, nearly constant (0–5 min without supervision) or close (0–15 min without supervision) supervision was recommended in safer locations, with constant supervision still recommended in high-risk situations. Only with older children was there an absence of consensus regarding supervision. The implications of these results for future injury prevention research are discussed.     

School teachers' control and involvement in their own evaluation

Summary For the technical, sociological-psychological, and political benefits of teacher participation in evaluation to occur, new structures and policies concerning evaluation must be put into place. Teachers must be given stagewise support in developing increased involvement and control. But finally, those policy makers, evaluation program designers and researchers who plan for teacher evaluation must act to more completely include teachers in their own evaluation. A great deal of good is at stake in the opportunity to increase teacher participation in teacher evaluation.     

SALUS: online co-operation between South Australian health libraries

The establishment of the South Australian Health Libraries Consortium led to the development of the SALUS project which enabled the online delivery of core health, clinical information and bibliographic databases with full-text resources across South Australian government health services. This was the first venture of Australian health librarians to create an online consortium. This article discusses the policy and management issues surrounding the implementation of the SALUS project and its influence on the evolution of the health Libraries Consortium over several years. Lessons learned during this process included: the necessity to plan well ahead yet to remain flexible in implementing those plans, to avoid procedure becoming more important than improvization during planning, to be willing to take well judged risks on occasions, and to be fully aware of changing circumstances in the project's funding and political environment. The importance of securing influential advocates outside of the participating libraries to support continued project funding is also considered.