Thesis (M.Tech.:Chiropractic)-Dept. of Chiropractic, Durban Institute of Technology, 2005 xi, 123 leaves ; 30 cm / The differential diagnosis of back and leg pain should include sacroiliac joint disease as the prevalence of sacroiliac joint pain appears to range from 13%-30%, thus making the sacroiliac joint a significant source of pain in patients with chronic low back pain. Sacroiliac syndrome is well-defined and usually presents with pain over the sacroiliac joint in the region of the posterior superior iliac spine, with possible referral to the buttock, groin, and leg. Most patients with sacroiliac syndrome seem to present with spastic or hyperactive muscles which leads to increased pain and decreased range of motion. Because of the close proximity of the Piriformis muscle to the sacroiliac joint, it is likely to be one of these hyperactive muscles. Various studies on low back pain, including a study on sacroiliac syndrome, have shown a correlation between low back pain, hip rotation range of motion asymmetry, and decreased hip mobility. In addition, the muscles responsible for movements of the hip have an overlapping innervation with the hip joint (L2 to S1) and sacroiliac joint (L2 to S3). It is assumed that the hypertonic muscles associated with sacroiliac syndrome decrease hip joint proprioception as the proprioceptors are facilitated erratically in a highly facilitated neuronal pool common to the innervation levels of the sacroiliac joint and the hip and associated with the level of the involved hypertonic muscle. This is thought to result in aberrant proprioceptive function at the identified levels, affecting the hip. Thus the aim of this study was to investigate the effect which sacroiliac joint manipulation had on hip functional ability in patients suffering from sacroiliac syndrome by means of various measurement tools: . Active hip joint ranges of motion were assessed using an Inclinometer, . Pressure threshold of the Piriformis muscle was measured by using an Algometer, and . Hip joint proprioception was assessed by measuring joint position sense of the hip joint using an Inclinometer.

Single-carrier linear modulation techniques combined with frequency-domain equalization provide a viable alternative to multicarrier techniques for combating multipath fading in channels with large delay spread. Such modulations tolerate frequency offset and have well controlled peak to average power ratio. They have comparable complexity to orthogonal frequency division multiplexing (OFDM) systems, and are more robust to synchronization errors. If error correction coding is used, then information can be iteratively passed between the equalizer and the decoder to improve performance. This is referred to as turbo equalization. To date, several turbo equalization schemes have been proposed, but little work has been done to address the problem of channel estimation for the turbo equalization process. The work in this thesis considers frequency-domain turbo equalization with imperfect channel state information (CSI) at the receiver for different wireless channels. A receiver structure incorporating joint frequency-domain turbo equalization and time- domain channel estimation is developed. The novelty of this scheme lies in the combination of time-domain channel estimation and frequency-domain turbo equalization, and in its extension to high level modulation formats. The performance of the system is investigated by a combination of analysis and computer simulation. It is found that the system performs well over a range of dispersive channels.

Bien que certaines règles générales aient été déterminées pour la conception de joints tubulaires collés structuraux, aucune procédure systématique d'optimisation ne permet de déterminer la nature des configurations optimales ou les règles de conception du joint qui sont propres à l'application envisagée. Dans ce contexte, l'objectif principal de cette Thèse est d'élaborer une procédure d'optimisation multiobjectif qui permet d'identifier des configurations globalement optimisées de joints tubulaires collés à simple recouvrement soumis à différents types de chargements simples et à un chargement combiné. La procédure d'optimisation proposée se détaille en quatre étapes : 1) identifier les propriétés et loi de comportement des matériaux pour toutes les pièces qui forment le joint, 2 ) élaborer un modèle numérique d'analyse par éléments finis dans lequel toutes les dimensions géométriques constituent des paramètres dimensionnels, 3) réaliser une étude paramétrique pour identifier les paramètres qui influent de façon non négligeable les fonctions objectif impliquées dans les études d'optimisation subséquentes et 4) définir le problème d'optimisation, c'est-à-dire les variables d'optimisation, les fonctions objectif et les fonctions de contrainte, et exécuter les études d'optimisation. Cette procédure est employée pour réaliser un total de 17 études d'optimisation pour un joint tubulaire collé à simple recouvrement soumis à un chargement en traction pure (4), en torsion (2) et en flexion ordinaire (4) de même qu'à un chargement combiné (7). Les résultats de ces études fournissent de 20 à 229 configurations optimales et permettent de faire ressortir des règles de conception propres à l'application du joint. Les originalités apportées par cette Thèse ont principalement trait à la généralité de l'approche proposée pour la recherche d'une conception optimale d'un joint tubulaire collé. Plus spécifiquement, l'introduction de paramètres dimensionnels qui définissent l'entièreté du modèle du joint, la considération de plusieurs fonctions objectif conflictuelles dans l'optimisation sans accorder d'importance relative à chacune d'entre elles et l'application d'un chargement composé d'une combinaison de chargements simples (traction, torsion et flexion) constituent les éléments d'originalité de cette Thèse.

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The study of the human motion as a discipline is ancient almost like the man. Early theories and observations on these topics can be found in Hyppocrates' and Galeno's work. More recently Duchenne de Boulogne (1867), Marey (1885), Braune and Fisher (1888), Sherrington (1933), Luria and finally Haken (1996) applied new techniques to the study of movement trying to understand and localise also the main areas of the brain involved during motion. Despite the richness of the literature produced, "man in motion" still represents a fascinating and partially unknown theme to deal with, particularly in the dynamic behaviour of the arms during the execution of specific tasks. Such movement, indeed individual expression of the complex interaction of biological subsystems (brain, muscles, skeleton, etc. ) against the surrounding environment, hides nowadays its features and very few data are available on its kinematic and dynamic response. This gap is largely due to the lack of knowledge on the dynamic movement of the "shoulder complex" and of the related muscles involved during motion. In fact, the large number of degrees of freedom to be measured and the high deformability of skin and soft tissues prevent the direct measurement of skeletal movements and contribute to increment the above described indetermination. Against this complex background, the rehabilitationist faces the pragmatic difficulties to decide which joints require attention as a priority or, in the case of biological damage, to assess the degree of impairment and subsequent recovery. As a result, clinical assessmentis performed by the use of relatively elementary test tasks, which can be monitored either by timing or by some indirect measurement of the success of the execution. The aim of the present research is then to provide new means of measurements to be used for gaining objective information on the motion particularly of "non visible" joints like the shoulder complex in order to characterise properly their motion and, in turn, the workspace of the arm.

One of the most poorly understood co-morbidities associated with obesity is the pathway to osteoarthritis of the knee. To implement appropriate preventative strategies, it is important to explore how obesity is a causal factor for osteoarthritis. The present research compared the kinematics and kinetics of a group of young obese, but otherwise healthy, adults to a group of young, healthy-weight adults, in an attempt to identify mechanical abnormalities at the knee during walking that may predispose the obese to osteoarthritis of the knee. Optotrak motion capture (Northern Digital Inc. Waterloo, Ontario) and a forceplate (AMTI OR6-7, Advanced Mechanical Technology Inc, Watertown, MA) were used to measure ground reaction forces and moments of 16 participants – 8 obese and 8 sex-, age- and height-matched healthy-weight – to analyze knee joint kinematics and kinetics at three walking speeds. Participants wore an accelerometer (ActiGraph GT3X, Fort Walton Beach, USA) for seven days to measure daily steps counts. Dependent t-tests were performed to determine group differences in ground reaction forces, knee angles and knee moments, as well as knee adduction moment impulse and cumulative knee adductor load (CKAL). The obese group walked at a significantly slower self-selected speed (p=0.013). While not statistically significant, the obese group did present with a more valgus mean dynamic knee alignment than the health-weight group. A significantly greater maximum abduction angle (p=0.009) and smaller minimum knee flexion angle at heel contact (p=0.001) was found in the obese group. A significant difference was found in the peak medial rotation moment in the transverse plane (p=0.003). A greater stance duration lead to a significantly greater knee adduction moment impulse (p=0.049) in the obese group. While significant group differences were not found in the steps per day, the obese group had a significantly greater CKAL (p=0.025). Obese young adults with healthy knees demonstrated a gait pattern of reduced medial knee joint compartment loading through greater knee abduction, medial knee rotation and a slower walking speed compared to matched controls. The ramifications of gait modifications on long-term musculoskeletal health remain unknown, but compensations may lead to increased risk of osteoarthritis of the knee.

Consider the problem of designing capacity-achieving codes for multi-terminal communication scenarios. For point-to-point communication problems, one can optimize a single code to approach capacity, but for multi-terminal problems this translates to optimizing a single code to perform well over the entire region of channel parameters. A coding scheme is called universal if it allows reliable communication over the entire achievable region promised by information theory. It was recently shown that terminated low-density parity-check convolutional codes (also known as spatially-coupled low-density parity-check ensembles) have belief-propagation thresholds that approach their maximum a-posteriori thresholds. This phenomenon, called "threshold saturation via spatial-coupling," was proven for binary erasure channels and then for binary memoryless symmetric channels. This approach provides us with a new paradigm for constructing capacity approaching codes. It was also conjectured that the principle of spatial coupling is very general and that the phenomenon of threshold saturation applies to a very broad class of graphical models. In this work, we consider a noisy Slepian-Wolf problem (with erasure and binary symmetric channel correlation models) and the binary-input Gaussian multiple access channel, which deal with correlation between sources and interference at the receiver respectively. We derive an area theorem for the joint decoder and empirically show that threshold saturation occurs for these multi-user scenarios. We also show that the outer bound derived using the area theorem is tight for the erasure Slepian-Wolf problem and that this bound is universal for regular LDPC codes with large left degrees. As a result, we demonstrate near-universal performance for these problems using spatially-coupled coding systems.

Whiplash-related injuries and manifestations, typically neck pain, following car collisions are known to potentially disable individuals with a high and increasing cost to society. There is limited knowledge regarding the temporomandibular joint (TMJ) sequelae following whiplash trauma. Previous studies are typically based on retrospective data and few follow-ups are prospective and controlled in design. Furthermore, previous follow-ups have not included magnetic resonance (MR) imaging, which is a prerequisite for verification of TMJ status. The aims of this prospective long-term study were (i) to determine frequency of inaccurate recall of TMJ symptoms in patients with a history of whiplash trauma, and (ii) to evaluate incidence, prevalence and progression of TMJ pathology, verified with MR imaging, and TMJ symptoms in patients after whiplash trauma, compared with the natural course in matched volunteers. We studied 60 consecutive patients who had neck symptoms following a rear-end car collision and were seen at a hospital emergency department. Bilateral TMJ MR imaging and clinical examination were performed at inception and at follow-up on average 15 years later. A self-administered questionnaire regarding TMJ symptoms (pain, dysfunction, or both) and a subsequent interview were performed at inception, at the one-year, and 15-year follow-up. Fifty-seven patients (95%) participated in all three examinations (85% for MR imaging examinations). Concurrently, 53 volunteers matched by age and sex followed the same protocol. Fifty volunteers (94%) participated in all three examinations (89% for MR imaging examinations). Ethics approval of the study protocol and informed consent from all participants was obtained. The calculated agreement between each patient’s inceptive and retrospective reports on TMJ symptoms yielded a kappa value of 0.41 (95% CI 0.18-0.64). Sixteen patients (40%) had inaccurate recall one year after whiplash trauma. There was no statistically significant difference in TMJ symptoms reported by the patients to be present before whiplash trauma compared with matched volunteers at inception. Prevalence of TMJ symptoms increased significantly with whiplash trauma and the increase remained stable throughout the 15-year study period, which contrasted to the natural course in volunteers. After one year the difference in prevalence between patients and volunteers was 54% versus 21% (p=0.0003) and after 15 years 49% versus 18% (p=0.0017). There was no statistically significant difference between patients and volunteers in prevalence of TMJ disc displacement either at inception (63% versus 53%) or at 15-year follow-up (63% versus 55%). TMJ disc displacement was significantly more prevalent in symptomatic volunteers compared with asymptomatic volunteers (89% versus 31%, p=0.0002). Incidence or progression of MR imaging verified TMJ pathology did not differ between patients and volunteers. This prospective 15-year follow-up concludes - that future studies on TMJ sequelae following whiplash trauma should be prospective in study design with examinations conducted in close proximity to whiplash trauma. This allows for reliable baseline status and potential bias of inaccurate recall of symptoms is minimized. - that future controlled studies on TMJ pathology in patients should include control groups of not only asymptomatic but also symptomatic volunteers in order to avoid potentially biased conclusions. - that one of three patients exposed to whiplash trauma can be expected to develop TMJ symptoms beyond that which corresponds to the natural course in volunteers. This finding and previously reported impairment of jaw function in patients with symptoms after whiplash trauma points to the need for including TMJs and related muscles in routine medical examinations of patients with symptoms following whiplash trauma. - that adult individuals presenting with no or mild TMJ symptoms seldom show development or aggravation of TMJ pathology and there is no or little indication for TMJ treatment of these adult individuals. This is in contrast to the higher progression of TMJ pathology previously reported for adult patients with TMJ symptoms, which requires treatment.