A comparison of forearm bone mineral density among collegiate gymnasts, distance runners, and non-athletes [abstract]

Purpose: Low regional bone mineral density (BMD) has been correlated with increased fracture incidence in several body regions. Higher forearm BMD has been observed in athletes of several impact loading sports and decreases the risk of Colles' fracture. The purpose of this study was to compare BMD in female collegiate gymnasts to a group of athletic controls (collegiate distance runners) and a group of non-athletic controls (non-athletes). Methods: Female collegiate artistic gymnasts (n=11), collegiate distance runners (n=9), and college-age non-athletes (n=25) underwent whole-body and dominant forearm DXA scans to assess whole-body BMD and body composition and sitespecific BMD of the dominant forearm. Weight and height were measured and used to determine BMI. Data for athletes were collected after the midpoint of their competitive seasons. Results: Differences were found between gymnasts and non-athletes and between gymnasts and runners at the total radius, 1/3 distal radius, and ultradistal radius (p<0.000), with gymnasts exhibiting significantly higher BMD at the three forearm sites than either distance runners or non-athletes. Differences between runners and non-athletes were not significant. Conclusions: The loading impact and site-specificity of gymnastics exercise on the forearm likely caused the increase in bone mineral density at both cortical and trabecular bone sites

The Effects of Laboratory Stress on Appraisal of Control in Bulimia

Recent work pertaining to bulimia has shown that bulimics tend to perceive themselves as having a decreased ability to control their environments, particularly when faced with a stressful situation. Results from studies examining the type or amount of stress experienced by bulimics have been inconsistent. The transactional model of stress, which calls for the examination of an individual\u27s appraisal of a situation, provides a more advanced method of measuring stress than has generally been used in past studies. The present study sought to examine bulimics\u27 perceptions of control in stressful and nonstressful situations using an in vivo behavioral task, Thirty female undergraduate bulimics and thirty noneating-oisordered controls engaged in a 40 trial contingency-learning task in which they estimated the amount of control they could exert. Half of the subjects were placed in a stressful condition, which involved a statement linking their performance with their intellectual functioning. The results of the study failed to demonstrate that bulimics perceived themselves as having less control than the noneating-disordered control subjects. However, this study was unable to address whether the stress could elicit differences in the appraisal of control as the stress manipulations proved unsuccessful. This study did find, however, that for bulimic subjects, increases in amount of behavioral involvement (i.e., button-pressing) did not result in increases in perceived control, as was the case for the noneating-disordered control subjects. These results are interpreted within a learned helplessness framework as suggesting that bulimics may not view themselves as being able to exert control over their lives, regardless of the amount of effort they exert

Mobilization of Trace Elements in Aquifers by Biodegradation of Hydrocarbon Contaminants

This study had two objectives: (1) to determine the extent of metal mobility within petroleum-contaminated aquifers, (2) to determine if biodegradation of petroleum hydrocarbons can explain metal mobility. The approach reviewed analytical results from 2305 groundwater sampling events, taken from 958 wells, located at 136 sites found at 53 Air Force installations. The study showed that high levels of metals are present at petroleum hydrocarbon sites where metals would not generally be expected. Of the metals with drinking water maximum contaminant levels (MCLs), mercury and silver were detected the least frequently. Barium and copper were detected at the sites, but fewer than 2.5 percent of the samples exceeded their MCLs. All other metals exceeded their MCLs in at least 2.5 percent of the samples, with antimony and lead exceeding their MCLs in 19 percent and 10 percent of samples, respectively. Higher concentrations of barium and manganese were most strongly correlated with petroleum hydrocarbon contamination, and relatively strong correlations also existed for aluminum, arsenic, iron, and lead. Major cations such as calcium, magnesium, sodium and potassium were least affected by petroleum hydrocarbons concentrations

Short-term aerobic exercise training in type 2 diabetes

Type 2 diabetes (T2D) is a worldwide problem, and people with T2D have impaired postprandial glycemia (PPG). While current pharmaceutical therapies are targeted to reduce glycosylated hemoglobin and may not be effective in improving PPG, exercise is an effective treatment to enhance postprandial glycemic control in patients with T2D. As little as seven days of aerobic exercise has been shown to reduce PPG, but the mechanisms by which this occurs are not understood. Further, the assessment of PPG generally is done using a non-physiological glucose overload uncharacteristic of normal human feeding. Thus, the primary aims of this dissertation were: 1) to identify tissues contributing to changes in glycemic control after short-term exercise training and identify the systemic mechanisms by which exercise improves overall PPG in patients with T2D, and 2) to determine if a mixed meal tolerance test is a more valid tool for assessing improvements in glycemic control following exercise training than the standard oral glucose tolerance test in T2D. Our findings support that improved insulin sensitivity is an early adaptation of exercise training, but we did not see improvements in overall PPG in the sample studied. We also found that a mixed meal test is an effective alternative to the oral glucose tolerance test in assessing differences in PPG. Collectively, when viewed in the presence of the existing literature, these data suggest that while exercise training is ultimately known to enhance postprandial glycemic control, and testing this with a mixed meal test is a viable alternative to the current oral glucose tolerance test, subjects with T2D have variable responses and may not always see improvements in PPG following one week of aerobic exercise training

Temporal-Difference Learning to Assist Human Decision Making during the Control of an Artificial Limb

In this work we explore the use of reinforcement learning (RL) to help with human decision making, combining state-of-the-art RL algorithms with an application to prosthetics. Managing human-machine interaction is a problem of considerable scope, and the simplification of human-robot interfaces is especially important in the domains of biomedical technology and rehabilitation medicine. For example, amputees who control artificial limbs are often required to quickly switch between a number of control actions or modes of operation in order to operate their devices. We suggest that by learning to anticipate (predict) a user's behaviour, artificial limbs could take on an active role in a human's control decisions so as to reduce the burden on their users. Recently, we showed that RL in the form of general value functions (GVFs) could be used to accurately detect a user's control intent prior to their explicit control choices. In the present work, we explore the use of temporal-difference learning and GVFs to predict when users will switch their control influence between the different motor functions of a robot arm. Experiments were performed using a multi-function robot arm that was controlled by muscle signals from a user's body (similar to conventional artificial limb control). Our approach was able to acquire and maintain forecasts about a user's switching decisions in real time. It also provides an intuitive and reward-free way for users to correct or reinforce the decisions made by the machine learning system. We expect that when a system is certain enough about its predictions, it can begin to take over switching decisions from the user to streamline control and potentially decrease the time and effort needed to complete tasks. This preliminary study therefore suggests a way to naturally integrate human- and machine-based decision making systems.Comment: 5 pages, 4 figures, This version to appear at The 1st Multidisciplinary Conference on Reinforcement Learning and Decision Making, Princeton, NJ, USA, Oct. 25-27, 201

Effect of carrageenan on the non-specific resistance of mice to injected syngeneic tumour cells, alone or in mixtures.

The mechanisms of non-specific resistance to syngeneic methylcholanthrene-induced fibrosarcomas of mice were investigated. Results showed that a small tumour graft of 0.05 X 10(5) cells is greatly enhanced in growth when admixed with large numbers of cell fragments, killed cells or viable non-replicating cells. The enhancement of small tumour grafts in cell mixtures was found to be non-specific. Carrageenan, a known anti-macrophage agent, significantly increased tumour growth in normal mice. However, it did not enhance the increased tumour growth of 0.05 X 10(5) cells mixed with 10(6) viable, non-replicating mitomycin C-treated tumour cells. The latter observation indicates that carrageenan and admixed cells interfere with the same tumour-inhibitory mechanism and therefore cannot produce additive effects. The results give support to the concept of a non-specific macrophage "surveillance" system which appears crucial in controlling tumour growth, since it determines the establishment of small numbers of tumour cells while they can still be easily destroyed

The Effect of Tumour Growth on Immune Competence: A Study of DMBA Mammary Carcinogenesis in the Rat

Circulating antibody response to flagella antigen has been measured in three groups of Sprague-Dawley rats after feeding with 7.12.DMBA in an attempt to differentiate carcinogen and tumour growth as causative agents in the depression of immune response seen in these animals. DMBA fed female rats developing tumours had progressive depression of both primary and secondary response as compared to control animals, and 7S and 19S antibody fractions were equally affected. Removal of tumours did not result in recovery of response. Attempts to prevent tumour development by mammectomy after DMBA feeding were unsuccessful, but the similar number of tumours found in this group was associated with an equal degree of antibody depression to that seen in the first experiment. Male animals fed DMBA did not develop malignant tumours, and showed no depression of immune response. Results suggest that tumour development plays a part in the depression of circulating antibody response seen in these animals, but that it is not directly related to the number of tumours, and is not reversible by tumour excision

A freshman seminar course evaluation : short- and long-term academic outcomes

Includes vita.Freshman seminar courses are designed to enhance a student's first year experience and help students succeed academically. Review of the literature found studies on seminar courses focused on short-term outcomes such as first year GPA, credit hour completion, or year one to year two retention. Studies looking long-term used graduation rates. No literature was found looking at GPA or credit hour completion past year one. Using propensity score matching to account for selection bias, t-tests, and regression analyses, this research attempted to find if enrolling in the SSC 1150 College Success course was associated with positive short- and long-term academic outcomes. Results from unmatched data found, students who took the course had lower cumulative GPA's and credit hour completion in all four years, a higher year one to year two retention rate, and lower four-and six-year graduation rates. For matched students, those who took the course had a higher first year cumulative GPA and credit hour completion, but lower numbers than course takers in other years. Seminar takers still had a higher year one to year two retention rate, and lower four-year graduation rate, but their six-year graduation rate was higher than takers.Includes bibliographical references (pages 82-94)

An emerging learning design for student-generated 'iVideos'

This paper describes an emerging learning design for a popular genre of learner-generated video projects: Ideas Videos or iVideos. These advocacy-style videos are short, two-minute, digital videos designed âto evoke powerful experiences about educative ideasâ (Wong, Mishra, Koehler & Siebenthal, 2007, p1). We draw on a recent study in teacher education to present a structured description of a pedagogical approach to iVideo filmmaking. A visual learning design representation (Agostinho, Harper, Oliver, Hedberg & Wills, 2008) and a LAMS-based generic learning design template (Cameron, 2008) form part of this description

The Achilles tendon total rupture score : a study of responsiveness, internal consistency and convergent validity on patients with acute Achilles tendon ruptures

Background The Achilles tendon Total Rupture Score was developed by a research group in 2007 in response to the need for a patient reported outcome measure for this patient population. Beyond this original development paper, no further validation studies have been published. Consequently the purpose of this study was to evaluate internal consistency, convergent validity and responsiveness of this newly developed patient reported outcome measure within patients who have sustained an isolated acute Achilles tendon rupture. Methods Sixty-four eligible patients with an acute rupture of their Achilles tendon completed the Achilles tendon Total Rupture Score alongside two further patient reported outcome measures (Disability Rating Index and EQ 5D). These were completed at baseline, six weeks, three months, six months and nine months post injury. The Achilles tendon Total Rupture Score was evaluated for internal consistency, using Cronbach's alpha, convergent validity, through correlation analysis and responsiveness, by analysing floor and ceiling effects and calculating its relative efficiency in comparison to the Disability Rating Index and EQ 5D scores. Results The Achilles tendon Total Rupture Score demonstrated high internal consistency (Cronbachs alpha > 0.8) and correlated significantly (p < 0.001) with the Disability Rating Index at five time points (pre-injury, six weeks, three, six and nine months) with correlation coefficients between -0.5 and -0.9. However, the confidence intervals were wide. Furthermore, the ability of the new score to detect clinically important changes over time (responsiveness) was shown to be greater than the Disability Rating Index and EQ 5D. Conclusions A universally accepted outcome measure is imperative to allow comparisons to be made across practice. This is the first study to evaluate aspects of validity of this newly developed outcome measure, outside of the developing centre. The ATRS demonstrated high internal consistency and responsiveness, with limited convergent validity. This research provides further support for the use of this outcome measure, however further research is required to advocate its universal use in patients with acute Achilles tendon ruptures. Such areas include inter-rater reliability and research to determine the minimally clinically important difference between scores