M.Tech.

M.Tech.

M. Tech. / The aim of this study was to determine whether a combination treatment of strength training of the Gastrocnemius muscle and adjusting of the Tibiotalar joint would have a greater effect and influence on the strength of the Gastrocnemius muscles when compared to either strengthening the Gastrocnemius muscles or adjusting the Tibiotalar joints alone. Thirty participants from the surrounding community of the University of Johannesburg were randomly divided into one of three groups, with an equal male to female ratio within each group. Group A received a strength training protocol directed at the Gastrocnemius muscles. Group B received Chiropractic adjustment therapy directed at the Tibiotalar joints and Group C received a combination of a strength training protocol of the Gastrocnemius muscles in addition to Chiropractic adjustment therapy directed at the Tibiotalar joints. All three groups received 6 treatments on alternate days over a two week period. Objective data was collected by means of a surface Electromyograph (sEMG) taken pre- and post-treatment on the 1st, 3rd and 6th appointments, and muscle strength testing was measured using an Isometric Dynamometer post-treatment on the 1st, 3rd and 6th appointments. Demographic data was collected and evaluated from the Case History, Pertinent Physical Examination, Demographic Data Questionnaire and Physical Assessment Form. In executing the comparison, it was anticipated that all three groups would be effective, but the group undergoing the combination treatment would have the best improvement on the Gastrocnemius strength overall, followed by the adjustment group and then the strengthening group. It could then be concluded that Chiropractic adjustment therapy would provide a safe, cost effective treatment and preventative measure of injury to the Gastrocnemius muscles. Treatment proposed in this research could thus serve as an adjunct and preventative therapy in current rehabilitation treatment protocols in athletes as well as in the general public. The results obtained from the study demonstrated that there was no statistically significant improvement in either of the groups however, there was a definite effect from the treatment protocols in each group that would warrant further investigation. There is a definite link between adjusting the Tibiotalar joint and affecting the Gastrocnemius muscle. Therefore, treating the joint can help the Gastrocnemius muscle to reach its optimal functionality. In conclusion, the study showed that Chiropractic adjustment therapy of the Tibiotalar joint and strengthening of the Gastrocnemius muscles had a combination effect on its strength and endurance that was greater than either of the treatments alone. From these results, it would be prudent to incorporate this treatment protocol to serve as an adjunctive therapy in rehabilitation and training protocols.

M.Tech.

M.Tech.

This thesis is a collection of four separate papers with a core theme: commodity futures manipulation. It aims to answer three important questions. How vulnerable are futures markets to manipulation? What are the effects of manipulation? How should futures markets be regulated? We first set up a one-shot game-theoretical model (Chapter 2) with certain classes of heterogeneously informed traders to consider how vulnerable a futures market to manipulation is, what influences this vulnerability and how manipulation affects the functioning of the market. This model predicts that futures manipulation may occur in equilibrium with a positive possibility if the deliverable supply is less than perfectly elastic, and the large trader possesses a certain amount of private information (here relating to his "type"), and more important, the functioning of futures markets is adversely affected by manipulation. In Chapter 3, we attempt to extend the above analysis into a dynamic context with a slightly modified market structure with the purpose to show how a large trader can manipulate a market through dynamically strategic trading when the hedger trades rationally, observes contract delivery process and may opt out of futures trading. This model also predicts a positive probability of manipulation in equilibrium. One interesting result from this model is that the adverse effects of manipulation may be lessened due to the introduction of exogenous uncertainty in a futures market. This may justify certain types of regulation against manipulation initiated by exchanges or regulators, such as trading for liquidation only, emergency price or position limits, etc. Chapter 4 moves to investigate empirically the economic effects of the alleged Sumitomo manipulation on the London Metal Exchange (LME). The results support our theoretical analysis. We find the evidence that the manipulation not only reduced the accuracy of "price discovery", but also influenced the basis and basis risk in the futures market. Thus the functioning of the LME was undermined. Furthermore, by comparing the actual LME cash price with a VAR forecast, we find that the LME cash prices were generally above the forecast prices during the period of alleged manipulation, but not significantly. Finally, we discuss the regulatory implications of futures manipulation in Chapter 5, and argue that manipulation should be one of the major concerns for futures regulation. We also undertake a comparative study of futures regulation in the US and the UK, and propose specifically how cost-effective futures (derivatives) regulation may be achieved in the UK.

M.Tech.

This thesis has two themes. Firstly, it concerns the original application of holographic beam shaping, employed through the methods associated with optical manipulation, to three microscopic fields of research. Secondly, it studies the optical trapping of aerosol droplets through experimentation and computational modelling. The aims are to not only provide an account of the work carried out but also a base for future researchers and students. Chapter 1 provides an introduction to the field of optical manipulation and the relevance of my studies. Chapter 2 outlines the construction of an optical tweezers which is the basis of advanced experimental work described in later chapters. It also overviews how optical tweezers operate and are quantified. In chapter 3 I describe how beam shaping is implemented for my investigations with a spatial light modulator and phase-only holograms. I detail the algorithms and software written before discussing their performance and finally the optimisation of the apparatus. Chapter 4 describes three original applications of beam shaping, including the trapping and coagulation of multiple aerosols, the manipulation of filamentous fungi hyphal tips and novel digital microfluidic operations using thermocapillary forces. I also lay down preliminary results for observing orbital angular acceleration using beams carrying orbital angular momentum. To study single optically trapped aerosols I use two methods. Firstly, their Brownian motion is investigated through sub diffraction limit position detection. Unique results in optical tweezers are shown with liquid droplets behaving as under-damped Brownian oscillators. Through these studies I demonstrate a new technique for sizing trapped aerosols, with significant advantages over current methods. I also show that the droplets can be be parametrically excited which can result in trap failure. Secondly, in chapter 6, I use a theoretical model to describe the forces imparted to a trapped droplet. I extend current theories to include the effects of a three medium focal region to accurately describe airborne optical traps. The work qualitatively explains the phenomena observed experimentally. The work contained here leaves much scope for future investigations, for which I provide an overview in chapter 7.

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