The objective of the present research was to establish the biomechanical, physiological and perceptual responses of male operators to dynamic pushing tasks. The pushing tasks were performed using an industrial pallet jack with varying load/frequency combinations, in a controlled laboratory environment. Thirty healthy male subjects comprised the sample. Experimental procedures were conducted utilising the Chatillon ™ Dynamometer to measure force output in the initial, sustained and ending phases. The K4b2 Ergospirometer was used to assess physiological responses (heart rate and oxygen consumption [V02])' Nine recorded forces and nine experimental conditions formed the basis of this study, with subjects required to push three loads (200kg, 350kg, 500kg) at three frequencies (1120 sec, 1/40 sec, 1/60 sec) at a speed of 3.6km.h-1 over 14 metres on a co-efficient of friction controlled walkway for six minutes. Gait analysis, along with perceptions of exertion (,Central ' and 'Local' RPE) were collected during the third and sixth minutes of each condition . Body discomfort and contribution were identified upon completion of each condition. The results demonstrated that load and frequency interacted to influence responses within each domain. Increasing loads required increased force output during each stage of the push, which had a concomitant effect on physiological and perceptual responses. Significant differences arose between the initial, sustained and ending forces for each load, showing the direct relationship between load and force exertion. The combination of heaviest load/quickest frequency required the greatest physiological output, exceeding recommended guidelines for heart rate, V02 and energy expenditure responses. Intermediate combinations required moderate and acceptable energy cost. Linear relationships were established between heart rate and oxygen consumption , as well as between load and V02 , thus providing industrial practitioners an opportunity to evaluate task demands in situ. The combination of high forces and elevated physiological responses increased the subjective rating of the condition. The results emphasise the need to holistically consider all contributing factors in a dynamic pushing task. Dynamic pushing tasks place biomechanical, physiological and perceptual demands on the human operator, which must be minimised in order to ensure that this form of manual materials handling becomes sustainable in the long term.

The main purpose of this study was to assess the effect of progressive resistance training on the blood lipid profile in post-menopausal women. Thirty-four female subjects aged 50 to 75 years were selected from the population of Grahamstown, South Africa. All participants were previously sedentary and possessed at least one lipid profile abnormality but were otherwise healthy. Pre-tests included a sub-maximal stress Electrocardiogram, measures of stature, mass, central and limb girths as well as an oral glucose tolerance test (OGTT) and a total blood lipid profile. Participants took part in a 24-week progressive resistance training programme, consisting of three supervised sessions per week, each lasting 45 minutes and were not permitted to lose more than 10% of initial body mass during the 24-week study. All pre-test measures, excluding the stress ECG and the OGTT, were repeated every four weeks for the duration of the study. Results were that body mass, body mass index and waist-to-hip ratio did not change. Girth measures at mid-humerus, chest, waist, hip, mid-quadricep and mid-gastrocnemius all decreased significantly (p=0.05). LDL-cholesterol increased significantly over the course of 24 weeks (3.61mmol.L-1 to 4.07mmol.L-1) as did total cholesterol (5.81mmol.L-1 to 6.24mmol.L-1). Triglyceride concentration remained unchanged and HDL-cholesterol decreased significantly between the pre-test measure (1.55mmol.L-1) and the measure after six months (1.42mmol.L-1). It can be concluded that the blood lipid profile in a sample of post-menopausal women was not positively affected by a progressive resistance training programme over a 24 week period. / Maiden name: Kelly, Janet Erica

The psychophysical experiments and numerical modelling reported in the present study are an investigation into the encoding of relative location of intensity changes in the human visual system. The study attempted, successfully, to explain some geometric illusions resulting from closely spaced image features ('crowding'), and determined the nature of information necessary for making judgments about the separation of intensity changes for different stimulus configurations. Experiments performed fell into two basic categories; those concerned with spatial interference, and studies of spatial interval judgments. The first set of experiments, studying spatial interference with relative localisation for intensity changes, was based on measurements made with stimuli composed of lowpass filtered bars and edges. The most successful model, which accounted for all of the data, was Watt and Morgan's (1984, 1985) MIRAGE; the results suggest that a good explanation of some geometric illusions can be derived using the principles of low-level vision. Spatial interference is strong evidence for combination of information across spatial scales, and the MIRAGE algorithm makes some highly accurate predictions. Relating the separation of image features is a fundamental task for the visual system, but there is no clear understanding of what information the system has available to perform this task. The second set of experiments explored the perception of separation, and precision of judgments of separation, for bars with a variety of orthoaxial contrast profiles. The data indicate that information is combined across spatial scales (as in MIRAGE) under certain circumstances in making separation judgments; this combination of information across scale occurs when the information on the scales combined is in agreement (ie. all scales have some task-related information), but when variance is added on coarser scales which is not relevant to the task, the system is capable of selecting the finest scales of filters available, and using only the information in the finest scale. This adaptive scale-selection process operates even at very brief exposure durations.

The moments that follow a perceptual decision can be as critical as the ones leading up to it. This thesis examines rapid olfactory decisions in mice and rapid changes of mind following an initial decision in humans. To study olfactory decisions, we trained mice to discriminate different odor concentrations in a novel head-fixed paradigm. Odor concentration is an important cue for localizing odor sources, from searching for food and mates to avoiding predators. However, little is known about how olfactory systems encode odor concentration. We found that mice could discriminate the different odor concentrations in as little as 80 ms after odorant inhalation. This is an unprecedented speed for olfaction and is fast even by the standards of other sensory modalities. We attribute this new insight into olfactory perception to our choice of motor output, accurate sniff measurement, and precise stimulus control. This result suggests that odor-based decisions can be very rapid and based on information over a very brief temporal window. To study changes of mind following an initial decision, humans made decisions about a noisy visual stimulus, which they indicated by moving a handle. Although they received no additional information after initiating their movement, their hand trajectories betrayed a change of mind on some trials. We modeled these changes of mind by extending the diffusion-to-bound model, originally developed to account for both the timing and accuracy of the initial decision. We propose that noisy evidence is accumulated over time until it reaches a criterion, or bound which determines the initial decision, and that the brain exploits information that is in the processing pipeline when the initial decision is made to subsequently either reverse or reaffirm the initial decision. Sensory and motor processing latencies ensure that not all of the information available from stimulus onset to movement initiation contributes to the initial decision. This model explains both the frequency of changes of mind, as well as their dependence on both task difficulty and whether the initial decision was accurate or erroneous.

The overarching aim of this thesis was to examine factors that affect post-exercise glycaemia and contribute to minimising the risk of hypoglycaemia after exercise. An inability to regulate circulating insulin concentrations is considered the primary gluco-regulatory defect within T1DM. Therefore, the aim of chapter 3 was to examine the effects of pre-exercise rapid-acting insulin reductions on blood glucose responses before and after running in T1DM individuals, to test the hypothesis that reducing pre-exercise insulin dose may help preserve post-exercise glycaemia. The results demonstrate that a 75% reduction to pre-exercise rapidacing insulin dose best preserved blood glucose before and after exercise, without increasing the risk of ketoacidosis, and reduced the risk of hypoglycaemia in free living conditions for 24 hours following running. An important factor determining blood glucose concentrations and subsequent patterns of fuel oxidation is the rate of appearance of carbohydrate into the circulation. Potentially, low GI carbohydrates may raise blood glucose less and increase the percentage contribution of lipids as a fuel because of a slower digestion. Therefore, the aim of chapter 4 was to examine the metabolic and blood glucose responses to ingestion of a high or low GI carbohydrate, combined with a 75% reduced insulin dose, before, during and for 24 hours after running. The results demonstrate that compared to a high GI carbohydrate, the low GI carbohydrate increased blood glucose concentrations less before exercise and maintained blood glucose better for 24 hours after running, via lower carbohydrate and higher lipid oxidation rates during the latter stages of running. After manipulating both the insulin dose and the pre-exercise carbohydrate GI, to improve post-exercise blood glucose concentrations, the timing of the ingestion of carbohydrate (alongside a reduced insulin dose) before exercise is an important factor which may further refine these strategies. Therefore, chapter 5 examined the metabolic and blood glucose responses to alterations in the timing of carbohydrate feeding and insulin administration prior to running. Our results demonstrated that administration of both a reduced rapid-acting insulin dose and low GI carbohydrate 30 minutes before exercise improved glycaemia for 24 hours after running, by reductions in carbohydrate oxidation, leading to increased carbohydrate availability post-exercise.

The impact of acute resistance exercise (RE) on glycaemia in type 1 diabetes (T1DM) individuals is poorly understood. Yet, such knowledge would have great use in improving our understanding of blood glucose control during and after the performance of RE. Increasing research in this area might help minimise complications associated with blood glucose vulnerability and potentially maximise health benefits related to RE which are known to be obtained by people without diabetes. The overarching aim of this thesis was to examine the impact of acute RE on glycaemia in T1DM individuals, and promote confidence in people with T1DM to partake in this form of exercise and lead a more physically active lifestyle. Exercise volume, or the total weight lifted during a RE session, is a primary component in the design of a RE session. Therefore, Chapter 3 examined the acute impact of manipulating RE session volume in T1DM individuals. The results demonstrate that exercise volume is an important factor in determining the blood glucose responses to RE; specifically, blood glucose concentrations rose above rest for one hour after one and two sets of similar intensity RE, but this exercise-induced hyperglycaemia was attenuated by increasing the volume of exercise by addition of a similar intensity third set of RE. Additionally, performing morning RE after an overnight fast and in the absence of rapid-acting insulin, did not induce acute hypoglycaemia, ketoacidosis or raise a marker of muscle damage, but caused metabolic acidosis in a dose-dependent fashion. Exercise intensity is a characteristic that is integral to the design of a RE session, and this characteristic might play a role in explaining the exercise-induced hyperglycaemia caused by the thirty minute (two-set) RE sessions in Chapter 3. The aim of Chapter 4 was to examine the impact of manipulating exercise intensity in T1DM individuals. The findings from this study demonstrate that performing a low intensity RE session evoked a similar magnitude of post-exercise hyperglycaemia and metabolic acidosis than a higher intensity RE session, when sessions were matched for total weight lifted. In an attempt to alleviate the consistent exercise-induced hyperglycaemia presented by the two-set RE session, the aim of Chapter 5 was to implement a modified algorithm that delivers an individualized dose of rapid-acting insulin after morning RE, to counter acute post-exercise hyperglycaemia in T1DM individuals. The results demonstrate that post-exercise rapid-acting insulin injection delivered by means of an algorithm resulted in reductions to post-RE hyperglycaemia without the occurrence of hypoglycaemia during two hours after exercise. However, during the subsequent twenty hours of freely living conditions, T1DM individuals remained unprotected from post-exercise hypoglycaemia as per a control condition. Overall, the findings of this thesis underpin some important factors that determine the glycaemic and metabolic responses to acute performance of RE, which may facilitate the better management of blood glucose around this form of exercise, in T1DM individuals.

The effects of induced mood on secretory immunoglobulin A (SIgA) were tested on 104 students (51 men & 53 women) using a mixed design with between subject factors of gender, induced mood (positive vs. negative), method of induction (writing about oneself vs. viewing a video), and a within subject factor, time (baseline vs. posttest). A split-plot multivariate analysis of covariance, controlling for salivary flow rate, did not support a causal link between induced mood alone and change in SIgA concentration. The effect of induced mood on blood pressure and heart rate was also examined. There were no significant main effects, but gender interacted with mood induction such that females experienced an increase in blood pressure in the positive mood induction condition. There was no significant effect of method of mood induction on SIgA, blood pressure, or heart rate. Stable personality traits, however, moderated the effects of mood induction. Persons who scored higher on depression and neuroticism, and lower on positive affect had significantly higher SIgA concentrations in the negative mood condition. There were no significant effects of personality traits on SIgA levels in the positive mood condition, nor did they interact with induced mood to change blood pressure or heart rate. These data suggest that although SIgA concentration may not be subject to short-term laboratory mood manipulations alone, changes in SIgA concentration may be associated with an interaction of stable personality traits and mood state, especially in the case induced negative mood.

The purpose of this study was to examine the effectiveness of behavioural self-control and relapse prevention strategies for increasing adherence in obese women during a 12 week supervised walking programme and in a six month unsupervised maintenance period. Fifty female volunteers aged 18-60 years who were inactive during the previous six months were matched on the variables of age and oxygen pulse and assigned to one of three groups. Each group participated in a 12 week supervised walking programme at the University of Victoria. Group one (n = 16) was exposed to the Behavioural Self-Control intervention (BSC). Group two (n = 17) was exposed to the Relapse Prevention intervention (RP). The control group (C, n = 17) received no intervention. The participants were expected to attend a minimum of three supervised sessions per week at which attendance was recorded and then participate in an unsupervised "4th Day Walk". Adherence to the 4th day walk was self-reported, as was adherence during the maintenance period. Fitness was evaluated three times during the study: (1) pre-intervention, (2) post intervention (3 months), and (3) post maintenance (6 months). Each fitness assessment included anthropometry and a submaximal treadmill aerobic fitness test to evaluate fitness changes and provide confirmation of self-reported adherence. Average adherence to the walking during the supervised programme was 75.38%, with 80% of the subjects completing the programme. Adherence to walking during maintenance declined from 73.17% in the first month to 50.87% in the sixth, with 60% of the individuals remaining involved at 9 months. No significant differences in overall program adherence or number and distribution of drop-outs were found. Significant differences were found when the final six weeks of the supervised programme were analysed separately, F(2,27) = 4.60, p<.02. The BSC group had significantly higher adherence than the RP group during this period. Overall adherence during maintenance was significantly different among groups, F(2,27) = 4.85, p<.02. The BSC group had significantly greater adherence than the C group. Physiological measures demonstrated that fitness increased during the programme and was maintained during the maintenance period for all groups. Rates of adherence, measured as either attendance or drop-out, were comparable to those reported for normal weight populations. The BSC intervention in an educational skill-based setting appeared to be an effective means of maintaining exercise behaviour over nine months. The RP intervention was no more effective than no intervention. The high levels of adherence obtained during this programme support the increasing use of exercise in the treatment of obesity. / Graduate

M.A. (Clinical Psychology) / The purpose of this study was to assess the differential and relative effects of cortical immaturity and non-cortical immaturity in specific learning disabled children on the development of maladaptive behavior. For this purpose twenty specific learning disabled children were selected according to certain criteria. This group was divided into a group of children with specific learning disabilities with cortical immaturity, and a group with specific learning disabilities without cortical immaturity. Acontrol group consisting of ten children without any learning disabilities was also selected. The three groups thus obtained were assessed on indices of aggression, withdrawal, class- and learning problems, and personal and social efficacy. The results indicated that specific learning disabled children manifested more maladaptive behavior than non-specific learning disabled children. Concerning the differential effect of cortical immaturity and noncortical immaturity in specific learning disabled children on the development of maladaptive behavior there were no meaningful differences. The recommendation was made that future studies should control contaminating variables among which socio-economic class differences and parental child rearing practices.

M.Sc. (Botany) / The purpose of this investigation was to determine the effects of various physical treatments (limitation of transpiring surface, removal of stem base and changing of vase water and different numbers of inflorescence per constant volume of vase water) on the browning of foliage and the rate of water absorption by Protea neriifolia in florescences. The binding capacity of lead acetate with flavonoids in vase media was also determined. The limitation of the number of leaves (transpiring surface) per peduncle resulted in less absorption of leached browning and stem plugging components. Regular removal of the stem base and changing of vase water inhibit stern blockage and accumulation of leached products in the vase medium. A large number of inflorescences in a limited volume of vase medium resulted in higher concentrations of leached flavonoids and other browning components. A reduced number of leaves per peduncle, regular removal of stern base and changing of vase water, as well as a limited number of inflorescences per constant volume of vase medium, ensured adequate continuous water uptake, which is essential to limit browning.