Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Der menschliche Gang und damit auch das Abrollverhalten und die Belastungssituation des Fußes wird von einer Vielzahl an extrinsischen und intrinsischen Faktoren beeinflusst. In dieser Arbeit soll der Einfluss des Körpergewichtes, im Speziellen der übermäßigen Körpermasse unter der Krankheit Adipositas sowie der Einfluss der plantaren, kutanen Sensorik auf den menschlichen Gang betrachtet werden. Die starken Auswirkungen von Übergewicht und Adipositas auf das muskuloskelettale System lassen sich vor allem an der hohen Prävalenz von Schmerzen an den unteren Extremitäten festmachen. Besonders häufig treten neben Schmerzen an Hüfte und Knie auch Beschwerden im Bereich des Fußes auf. Die Betrachtung kinetischer Auswirkungen von Übergewicht und Adipositas auf den Bewegungsapparat rückt daher zunehmend in den Fokus der bewegungswissenschaftlichen Forschung. Die aktuelle Studienlage lässt derzeit jedoch keine eindeutigen Schlussfolgerungen zu, in welcher Weise sich Adipositas mit steigendem Schweregrad auf das Gangmuster auswirkt. Besonders im Bereich des Fußes fehlen belastungsrelevante Informationen mit denen das Abrollverhalten des Fußes bestimmt und mögliche Fehlbelastungen erkannt werden können. Zur Behandlung von schweren Graden der Adiposits werden adipositaschirurgische Maßnahmen eingesetzt. Dadurch ist es möglich in kürzester Zeit einen starken Gewichtsverlust hervorzurufen. Unklar ist, ob sich das Gangbild nach einem entsprechenden Gewichtsverlust wieder normalisieren kann und Adaptationsvorgänge nach einem längeren Zeitraum nachweisbar sind. In zwei Studien soll daher das plantare Belastungsmuster unter Adipositas evaluiert werden. In Studie I wird dazu eine Kategorisierung nach dem Schweregrad der Adipositas vorgenommen und das plantare Belastungsmuster der jeweiligen Gruppen gegenüber dem einer normalgewichtigen Gruppe gestellt. Ein besonderes Augenmerk soll hier auf Belastungen im Fersen- und im Mittelfußbereich gelegt werden, da hier Schmerzen am häufigsten auftreten. Der Kenntnisgewinn aus dieser Studie soll vor allem zur theoretischen Herleitung der Entstehungsmuster von Schmerzen im Bereich des Fußes dienen, aber auch typische Gangmuster der einzelnen Adipositas Grade festhalten. In Studie II erfolgt die Betrachtung der plantaren Belastung nach einem adipositaschirurgischen Eingriff. Ziel dieser Studie ist es, Anpassungsprozesse nach einem massiven Gewichtsverlust im Gangverhalten zu bewerten und Faktoren, welche wesentlich zur Veränderung des Gangbildes beitragen, auszumachen. Die Ergebnisse können weiterhin Hinweise auf eine mögliche Notwendigkeit einer bewegungstherapeutischen Begleitung nach einem adipositaschirurgischen Eingriff liefern. Studie III beschäftigt sich mit den Auswirkungen einer Desensibilisierung der plantaren kutanen Sensorik auf das plantare Abrollmuster beim Gehen. Die kutanen Mechanorezeptoren sind wesentlich an der posturalen Kontrolle beim Stehen und bei dynamischen Bewegungsvorgängen beteiligt. Beeinträchtigungen in der Funktionsweise der plantaren kutanen Mechanorezeptoren bspw. in Folge einer diabetischen Polyneuropathie können zu Gangpathologien, einer erhöhten Sturzgefahr oder auch der Entstehung von Druckulzerationen führen. Die Stärke der Beteiligung der plantaren Sensorik am plantaren Belastungmuster ist jedoch nicht ausreichend erschlossen und soll daher in Studie III betrachtet werden.

Although the yellow press has been in existence in Great Britain and the USA since the start of the 19th century, it has only recently been introduced in the South African media environment. The mainstream press like Rapport and Beeld have showed certain characteristics of the yellow press for a while now, but rather present a combination of both trivial and more serious news to the reader. The arrival of the yellow media which brought along a more sensational approach to news became also visible in more serious papers. This phenomenon is called "tabloidisation". The yellow press can be distinguished from serious papers on the basis of its nature and presentation. These characteristics can be divided into three categories, namely news themes, language and style, and presentation. The yellow press can be recognised by the amount of news items that focus on scandals and gossip involving celebrities, sex and crime. These media communicate in a informal and an easy understandable way with the readers,. These publications often make use of crude language and the stories are mostly people-driven. The yellow press publication can be seen as an entertainment package, because the aim is to entertain the reader. A vivid news package is presented to the reader by using bold headlines, large photos, graphics, colour and a captivating front page. This study investigates the characteristics of the yellow press. It investigates whether and how these characteristics are presented under the categories news themes, language, style and presentation of three local daily tabloids, namely the Kaapse Son, Daily Voice and the Daily Sun. / Thesis (M.A. (Communication Studies))--North-West University, Potchefstroom Campus, 2009.

Although the yellow press has been in existence in Great Britain and the USA since the start of the 19th century, it has only recently been introduced in the South African media environment. The mainstream press like Rapport and Beeld have showed certain characteristics of the yellow press for a while now, but rather present a combination of both trivial and more serious news to the reader. The arrival of the yellow media which brought along a more sensational approach to news became also visible in more serious papers. This phenomenon is called "tabloidisation". The yellow press can be distinguished from serious papers on the basis of its nature and presentation. These characteristics can be divided into three categories, namely news themes, language and style, and presentation. The yellow press can be recognised by the amount of news items that focus on scandals and gossip involving celebrities, sex and crime. These media communicate in a informal and an easy understandable way with the readers,. These publications often make use of crude language and the stories are mostly people-driven. The yellow press publication can be seen as an entertainment package, because the aim is to entertain the reader. A vivid news package is presented to the reader by using bold headlines, large photos, graphics, colour and a captivating front page. This study investigates the characteristics of the yellow press. It investigates whether and how these characteristics are presented under the categories news themes, language, style and presentation of three local daily tabloids, namely the Kaapse Son, Daily Voice and the Daily Sun. / Thesis (M.A. (Communication Studies))--North-West University, Potchefstroom Campus, 2009.

Hand function is of great importance in the many daily activities that require well-coordinated hand and arm movements. Measurement of hand function is an essential element in the rehabilitation process, in order to facilitate medical diagnosis and determine developmental stages, functional levels, and the efficacy of treatment interventions. Basic requirements for any measurement used in clinics are that they are easy to use, relevant to the function being assessed, and valid and reliable. When scrutinizing the literature on hand function, important gaps were found with regard to measurement. For example, the reliability of grip strength with the Grippit in children has yet to be determined, and there are few evaluations of hand function measurements in Charcot-Marie-Tooth disease (CMT). Furthermore, laboratory measurements of hand function, which have the potential to provide more detailed information and insight into hand control, such as the role of the cerebellum in reactive grip control – have not been fully explored. The overall aim of the thesis was to achieve more knowledge on hand function; on the evaluation of measurements in different target populations; and on movement control of the hand. In the first study, the aim was to evaluate the test-retest reliability of the peak and sustained grip strength with Grippit in a sample of healthy children (n=58, 6-, 10- and 14-y-olds). This was followed by two studies examining hand function in an adult sample (n=20) diagnosed with CMT. The test-retest reliability of grip and pinch strength using Grippit, sensation with the Shape Texture Identification test (STI) and dexterity with the Box and Block Test (BBT) and Nine-Hole Peg test (NHP) were studied. The impact of the disease on daily life, measured with the Disability of the Arm, Shoulder and Hand questionnaire (DASH), and correlations between disability and various aspects of hand function, were also explored in this condition. The aim of the fourth study was to examine grip force response to unpredictable loadings of an object held in a pinch grip in subjects (n=9, 22-48 yrs) who had been diagnosed with a cerebellar lesion, compared with a healthy control group (n=11). The first study showed that test-retest reliability was good for both peak and sustained grip strength in healthy children. The mean and best of three trials were equally reliable, but differences in reliability were detected within different age groups. For example, the peak grip strength, best of three trials, was more reliable for the 6-y-olds (intraclass correlation coefficient (ICC)=0.96, standard error of measurement in percentage (SEM%)=6.3) and 14-y-olds (ICC=0.96, SEM%=5.2) compared with the 10-y-olds (ICC=0.78, SEM%=12.5). In the second study, evaluating measurements of hand function in subjects with CMT, grip strength proved to be reliable (ICC=0.99, coefficient of repeatability (CR)=26.7 N, coefficient of variation (CV)=6.6 %), but pinch strength was less reliable. The reliability was also good for the BBT (ICC=0.95, CR=11.5 blocks/min, CV=8.4%) and the NHP (ICC=0.99, CR=4.3 s, CV=3.9 %). However, a bias towards higher values was noted on the second test occasion with the BBT. The reliability of the STI test (kappa=0.87) was also very good in subjects with CMT. A limitation in this latter test was noted in terms of its ability to describe subjects either performing very well or very poorly. The results of the third study showed that hand function in CMT was reduced (p<0.001) to about 60% of that in healthy controls in each of the separate outcome measures, as well as by a constructed summary index of hand function. The median DASH score was 38.8 (range 0-66.7) and was clearly related to hand function (r=0.64-0.83). The results of the final study in subjects with cerebellar lesions showed that the ipsilateral hand had delayed and more variable response latencies e.g. 278±166 ms for loads delivered at 2 N/s, compared with healthy subjects (HS) 80±53 ms (p=0.005). The cerebellar subjects also used a higher pre-load grip force with the ipsilateral hand (1.6±0.8 N) than the HS (1.3±0.6 N (p=0.017)). Even the contralateral hand in subjects with unilateral cerebellar stroke showed a delayed onset of the grip response. In conclusion: Grip strength assessment in children with Grippit results in good reliability for peak and sustained grip strength, although the 10-y-olds were less reliable. In CMT the tested instruments can all be used to evaluate hand function, but certain factors, such as the number of trials used should be taken into consideration. The CMT subjects’ hand function was reduced and correlated with their self-experienced disability. However, clinicians should be aware that patients might score lower than expected on DASH, possibly due to a long process of adaptation. Cerebellar lesions can impair the reactive grip control in both the ipsilateral and the contralateral hand. These investigations have thus, as intended increased the knowledge of hand function. The studies have evaluated some measurements in different samples, which will help clinicians testing hand function.

College students and emerging adults have been found to be at risk for smoking cigarettes, drinking to excess, using illicit drugs, driving dangerously, and engaging in risky sexual and delinquent behaviour. Psychosocial correlates (Sensation Seeking, peer behaviour, parent behaviour, and peer and parent anti-substance use messages) from three domains of influence (personality, parent, and peer) were examined together to provide a greater context for the occurrence of such health-risk behaviours. The strongest predictor(s) of each behaviour were identified to better inform intervention practices. Three groups were compared— 1) those who never tried substances, 2) those who tried substances in the past, and 3) those who continue to use substances at present, in a population of emerging adults. Self-report data was gathered from 203 Collèges d'Enseignement Général Et Professionnel (CEGEP) students in the Montreal region. Measures included: Reckless Behaviour Questionnaire, Reckless Driving Measure, Health Behaviour Survey, Sensation Seeking Scale—Form V, and the Marlowe-Crowne Social Desirability Scale. Results revealed that peer behaviour was the most significant predictor of substance use in emerging adults, whereas parent behaviour was only a significant predictor of reckless driving. Sensation Seeking, specifically Disinhibition, was found to predict more global reckless behaviours, including illegal activities, such as stealing or using marijuana (p < .01). Neither peer nor parent anti-substance messages were significantly related to any of the health-risk behaviours measured in this study. It would appear that health-risk behaviours tend to be related to the same underlying factors but to varying degrees. Intervention implications are discussed.

Effect of lipids on binding characteristics of opioid receptors in membranes prepared from rat brain were studied. Lipid concentrations causing changes in specific binding of [3H]Endomorphin-1 (ProE1), an opioid agonist highly specific to mu-type opioid, [3H]Ile5,6deltorphin II (DIDI), an agonist ligand highly specific to delta type receptor and [3H]Naloxone (Nlx), a universal opioid receptor antagonist were determined. Inhibition of [3H]ProE1, [3H]DIDI and [3H]Nlx specific binding was also examined by homologous displacement experiments in the presence and absence of lipids. In order to understand whether the changes occurring in the specific binding is due to changes in equilibrium dissociation constant (KD) or maximum number of binding sites (Bmax), the equilibrium binding experiments were performed. Arachidonic acid (AA) inhibited binding of both agonist and antagonist ligand in a dose dependent manner with IC50 values of 0.15, 0.1, and 0.6 mM for [3H]ProE1, [3H]DIDI and [3H]Nlx, respectively. Kd values were not affected while Bmax values decreased 38 % and 76 % for mu, and delta receptor subtypes, respectively. For [3H]Nlx, Bmax values decreased 20 and 56 % in the absence and presence of 100 mM NaCl, respectively. Cholesteryl hemisuccinate (CHS) enhances (100 % of control) ligand binding at mu-sites however no effect was encountered at delta sites. Furthermore, CHS also enhances (50 % of control) the binding of antagonist ligand in the absence of NaCl. Bmax values were increased by 70 % for mu sites and 40% for antagonist ligand binding site. Under similar conditions Kd values were not affected. Phosphatidic acid (PA) and phosphatidylcholine (PC) exhibited negligible effect on ligand binding. PA decreased specific binding of ProE1 and DIDI by 16 and 10 %, respectively. Specific binding of antagonist ligand Nlx decreased 11 % in the presence of NaCl whereas in the absence of NaCl specific binding is very close to control. In the presence of PC specific binding of both agonist and antagonist ligands were around control values. In this study modulatory effect of lysophospholipids, lysophosphatidic acid and lysophosphatidylcholine on opioid binding sites were evaluated for the first time. Both lysophospholipids exhibited similar effects: decreasing specific binding in receptor subtype independent manner between 0.1 to 1 mM range. Kd values were not significantly affected, while remarkable decrease (45-75 %) in Bmax values were observed.

Motorcycle riding is rapidly increasing in popularity in Australia, attracting a much wider demographic of people than in decades past. Unfortunately, whilst the overall road toll in Australia has generally been reducing, the proportion of motorcycle-related fatalities has been rising in recent years. Further, the proportion of motorcycle-related fatalities in Australia is unacceptably high compared to other OECD countries. To reduce motorcycle-related fatalities on Australian roads, there is an urgent need to consider motorcyclists as distinct from other road users. This program of research facilitates the understanding of safety issues from a motorcyclist perspective and provides important information on factors influencing safe and unsafe rider intentions and behaviour.----- Study 1 explored what motorcyclists thought about the issues relevant to safety and to risk-taking behaviour on a motorcycle. The aim of this study was to develop a better understanding of the factors which influence on-road riding behaviour. Using the theory of planned behaviour (TPB), identity theory, social identity theory, and items based on moral norm and causal attribution theory, a set of questions was developed to guide focus group discussions with riders, police, rider trainers, and an advocacy group for motorcycle safety. Of the 43 participants in this study, only two were not motorcycle riders. This exploratory process revealed six common behaviours that most motorcyclists agreed were essential to safety or which related directly to riskier riding.----- Two behaviours were identified as being essential to rider safety by participants. The first was the necessity of being able to handle the motorcycle proficiently and skilfully. The second related to the need for riders to maintain a high level of concentration whilst riding and to stay aware of the changing road environment.----- The safety or riskiness of two other behaviours mentioned became a matter of debate amongst participants. First, some riders said that obeying the road rules was essential to their safety, whilst others reported that it was often necessary to break the road rules in order to stay safe. Second, the definition of what constituted 'riding whilst impaired' differed amongst riders. Most riders agreed that 'drinking and riding' was dangerous. However, for some, even one alcoholic drink before riding was considered dangerous, whilst others would ride after drinking provided they did not consider themselves to be over the legal BAC limit. Some riders stated that riding when they were tired was dangerous; however, fatigue was not considered a serious safety issue for many participants.----- Two further behaviours identified by participants were often associated with their accounts of crash involvement, yet not seen as intrinsically 'unsafe' by most riders. The first of these was the concept of 'pushing your limits'. Most riders interviewed appeared to enjoy pushing the limits of their ability on a motorcycle. Whilst agreeing that pushing the limits too far was dangerous, pushing them to a point that tested a rider's abilities was often reported to facilitate safety as this process developed a rider's skill. The second behaviour that was often mentioned in connection with crashes was extreme riding (e.g., performing stunts and riding at extreme speeds). The act of perfecting a stunt was often reported to result in the crashing of the motorcycle; although, these crashes were usually accepted as a normal part of the learning process. Once perfected, performing stunts did not appear to be considered an intrinsically unsafe behaviour; unless performed in traffic or other unpredictable situations. A sizable minority of both male and female participants reported riding at extreme speeds. These riders often argued that they could ride extremely fast, safely, on public roads provided certain conditions were met (e.g., good visibility, weather, road, and motorcycle maintenance).----- Study 2 [n = 229] operationalised the six behaviours discussed above into three 'safer' behavioural intentions (i.e., handle the motorcycle skilfully, maintain 100% awareness, not ride impaired) and three 'riskier' intentions (i.e., bend road rules, push the limits, perform stunts or ride at extreme speeds). A seventh item was added to provide a global measure of a rider's intention to ride safely. Multiple regression analyses were then performed to test the predictive utility of the TPB compared with several augmented models. The additional constructs used to augment the TPB included a specific subjective norm and group norm which related to the people a person rides with, self identity, sensation seeking, aggression as well as age, gender and riding exposure. The multiple regression analysis demonstrated that a greater proportion of variance could be explained in the case of the riskier riding intentions [R2 ranging from 57% - 66%] than the safer riding intentions [R2 ranging from 22% - 36%]. Therefore, this type of theoretical model may be better suited to investigating deliberate risk-taking intentions rather than an overall model of rider behaviour which includes errors and lapses or intentions to ride safely.----- In the final analyses, perceived behavioural control (PBC) proved to be a significant predictor of all four intentions towards the safer behaviours, and also towards intentions to "push my limits". Attitude was a significant predictor of the three riskier intentions. Although the standard subjective norm variable performed weakly, as it was only predictive of one intention, the specific subjective norm (i.e., the people that someone rides with) emerged as a significant predictor of four of the seven intention items and group norm was predictive of an additional intention item. This result indicates that the other people a person rides with may have a marked effect on behavioural intentions. Sensation seeking was found to be significantly related to four intentions, self identification as a safe or risky rider related to two intentions and a propensity for aggression was only significantly predictive of one intention.----- Study 2 did not find a significant relationship between the seven intentions and past crash history. However, correlational analyses found that people who had reported being involved in a serious crash in the past two years reported less PBC over their ability to ride as safely as possible and to perform stunts and/or ride at extreme speeds.----- In conclusion, this program of research provided insight into the issues riders feel are important to their safety, and has facilitated a greater understanding of the complexity of influences that impact on riding intentions and behaviour. The study also provided support for extending the traditional TPB model to include other measures of social influence, as well as person-related factors such as sensation seeking. The fact that PBC emerged as a predictor of five of the seven intentions suggests that there may be scope to enhance existing training practices to better address both safe and risky riding intentions. The influence of other riders also emerged as a strong influence on intentions, suggesting that strategies to address rider behaviour within the wider social context of riding may be a useful addition to future motorcycle safety or rider training initiatives. The social dynamics of motorcycle riding, within the context of road safety, is an area that clearly requires more investigation. Research into this area may provide the key to developing new approaches to promoting motorcycle safety which effectively integrate both the psychological and sociological aspects of riding; therefore, better reflecting the real challenges facing many riders on Australian roads today.