Effects of power variation on cycle performance during simulated hilly time-trials

It has previously been shown that cyclists are unable to maintain a constant power output during cycle time-trials on hilly courses. The purpose of the present study is therefore to quantify these effects of power variation using a mathematical model of cycling performance. A hypothetical cyclist (body mass: 70?kg, bicycle mass: 10?kg) was studied using a mathematical model of cycling, which included the effects of acceleration. Performance was modelled over three hypothetical 40-km courses, comprising repeated 2.5-km sections of uphill and downhill with gradients of 1%, 3%, and 6%, respectively. Amplitude (5–15%) and distance (0.31–20.00?km) of variation were modelled over a range of mean power outputs (200–600?W) and compared to sustaining a constant power. Power variation was typically detrimental to performance; these effects were augmented as the amplitude of variation and severity of gradient increased. Varying power every 1.25?km was most detrimental to performance; at a mean power of 200?W, performance was impaired by 43.90?s (±15% variation, 6% gradient). However at the steepest gradients, the effect of power variation was relatively independent of the distance of variation. In contrast, varying power in parallel with changes in gradient improved performance by 188.89?s (±15% variation, 6% gradient) at 200?W. The present data demonstrate that during hilly time-trials, power variation that does not occur in parallel with changes in gradient is detrimental to performance, especially at steeper gradients. These adverse effects are substantially larger than those previously observed during flat, windless time-trials.     

Perianal findings in prepubertal children selected for nonabuse: a descriptive study

The results of the perianal portion of a project designed to collect normative data of the anogenital anatomy from a representative sample of prepubertal children is presented. A total of 318 children were examined by three physicians from a child sexual abuse evaluation program. After screening for the onset of puberty and the possibility of undetected abuse, 267 subjects remained. The sample included 161 girls and 106 boys ranging in age from 2 months to 11 years. The perianal findings that were encountered with the greatest frequency included erythema (41%), increased pigmentation (30%), and venous engorgement (52%) after two minutes in the knee-chest position. Wedge-shaped smooth areas in the midline, with or without depressions, were found both anterior and posterior to the anus in 26% of the children. Anal skin tags/folds were discovered anterior to the anus in 11%. In 49% of the children there was some dilatation of the anus which opened and closed intermittently in 62%. Flattening of the anal verge and rugae occurred during dilatation by the midpoint of the examination in 44% and 34%, respectively. Perianal findings that were found infrequently in all subgroups included skin tags/folds (0%) and scars (1%) outside the midline, anal dilatation greater than 20 mm without the presence of stool in the rectal ampulla (1.2%), irregularity of the anal orifice after complete dilatation (3%), and prominence of the anal verge (3%). No abrasions, hematomas, fissures, or hemorrhoids were encountered. Less commonly detected findings within specific subgroups included perianal erythema in girls (32%) as compared to boys (57%), pigmentation in the lighter skinned white children (22%) when compared to black (53%) and Hispanic (58%) children, and venous congestion at the beginning of the examination (7%) when compared to the same findings after four minutes in the knee-chest position (73%). There were no perianal skin tags/folds found in the boys. The relatively high incidence of perianal soft tissue changes that were found in this study, when compared to the frequency of similar observations in children suspected of having been sexually abused, reemphasizes the caution medical examiners must exercise in rendering an opinion as to the significance of medical findings.     

Do digital natives differ by computer self-efficacy and experience? An empirical study

This study serves to validate a Chinese translation of the Digital Native Assessment Scale (C-DNAS) and assess if significant differences exist between a sample of students and teachers from a culture different than the one used in the development of the DNAS. Participants were 402 university students from one province in Mainland China. Results of the confirmatory factor analysis revealed that the C-DNAS possessed a stable factorial structure and was a valid measure among Chinese-speaking participants in Mainland China. Tests of measurement invariance revealed score equivalence among the students for each of the four factors of the C-DNAS: grew up with technology; comfortable with multitasking; reliant on graphics for communication; and thrive on instant gratifications and rewards, by computer self-efficacy and experience. Finally, tests of latent mean differences revealed significant differences in each of the four factors by computer experience but not by computer self-efficacy. Implications for research are discussed.     

Who are Rural Students? How Definitions of Rurality Affect Research on College Completion

Research in Higher Education - Given a revived national discourse about rural populations, more educational research on rural students is necessary, including ways that rural students transition to...     

Science diaries: a brief writing intervention to improve motivation to learn science

This study investigated the hypothesis that prompting students to self-assess their interest and understanding of science concepts and activities would increase their motivation in science classes. Students were randomly assigned to an experimental condition that wrote self-assessments of their competence and interest in science lessons or a control condition that wrote summaries of those same lessons. Writing activities were 10?min long and were given approximately once a week for eighteen weeks. Student motivation was assessed via self-report surveys for achievement goals and interest in science before and after the intervention. Students in the experimental condition showed higher endorsement of mastery goals and reported greater situational interest in science topics after the intervention compared to students who summarised the lessons. Increases in situational interest predicted higher individual interest in the domain. Results indicate an instructional practice requiring just 3?hours out of a semester of instruction was sufficient to achieve these effects on motivation in science classes.     

Response-cost punishment with pigeons: Further evidence of response suppression via token loss

Four pigeons responded on a two-component multiple token-reinforcement schedule, in which tokens were produced according to a random-interval 30-sec schedule and exchanged according to a variable-ratio 4 schedule in both components. To assess the effects of contingent token loss, tokens were removed after every second response (i.e., fixed-ratio 2 loss) in one of the components. Response rates were selectively lower in the loss components relative to baseline (no-loss) conditions, as well as to the within-condition no-loss components. Response rates were decreased to a greater degree in the presence of tokens than in their absence. To control for the effects of changes in the density of token and food reinforcement, two parts consisted of additional conditions where food density and token loss were yoked to those in a previous loss condition. In the yoked-food condition, tokens were produced as usual in both components, but the overall density of food reinforcement in one of the components was yoked to that obtained during a previous token-loss condition. In the yoked token-loss condition, tokens were removed during one component of the multiple schedule at a rate that approximately matched the obtained rate of loss from a previous token-loss condition. Response rates in these yoked components were less affected than those in comparable loss components, despite similar densities of token, exchange, and food reinforcement. On the whole, the results support the conclusion that contingent token loss serves as an effective punisher with pigeons.     

Beginning reading strategies in children experiencing contrasting teaching methods

Two groups of 4.5–5.5 year old children in their first year at school were examined; one taught by a whole word teaching method and one taught by a mixed whole word and phonological teaching method. The children were given a test to investigate their reading of normal words. The results of this test were subjected to a detailed error analysis and the two groups were examined in order to see if there were differences in the reading strategies they used. No evidence was found counter to the assumption that reading begins with a logographic stage. However, it was found that teaching method was having a significant impact on the reading strategies which the children adopted. In addition it was found that a number of children from the whole school appeared to exhibit letter by letter reading. This suggests that letter by letter dyslexia might in part be an extreme form of a strategy used by normal readers.     

Tampering with a Stable Process

This article presents a variation of the funnel experiment made famous by W. Edwards Deming. Ideally suited for classroom use, this exercise illustrates the disastrous consequences resulting from tampering with a stable process.     

Distributing and Showing Farmer Learning Videos in Bangladesh

Purpose: To describe the results of showing farmer learning videos through different types of volunteers.

Design/Methodology/Approach: Semi-structured interviews with volunteers from different occupational groups in Bangladesh, and a phone survey with 227 respondents.

Findings: Each occupational group acted differently. Shop keepers, tillage service providers, agricultural input and machine dealers reached fairly small audiences. Tea stall owners had large, male audiences. Non-governmental organisations and community-based organisations, reached more women. The cable TV (dish-line) operators showed the videos on local TV, but some were reluctant to do so again. The Union Information Service Centres showed the videos and reached women viewers. Half of the official government extension agents surveyed also showed the videos publically.

Practical Implication: This video featured maize, wheat and rice seeding machinery. Because the machinery is complex and requires hands-on training, this first video aimed to expose tillage and sowing service providers and farmers to the machinery, without trying to teach them how to use it. But some farmers were so interested that they watched the video many times to learn more about the equipment. Before farmers and service providers decide to buy machinery for direct seeding, they still want to see and learn from demonstration plantings, to examine first-hand how the crop behaves when planted with the new equipment.

Originality/Value: Video can be an effective way of sharing high-quality information with a large audience, if properly distributed.