3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item The geology of the Otjosondu manganese area: south west Africa(1959) Roper, HaroldGeological mapping and compilation of data from mining and prospecting operations in the Otjosondu area in South West Africa provided the information presented in this thesis. The geomorphology of the area is described and the general geology is discussed. Details of the complicated folding suffered by the Iamara rocks are presented. The petrology and petrography of' the outcropping representatives of the ancient sedimentary and intrusive rocks is described under the section on economic geology, interpretations of the complex structures of the ore bodies are presented. The mineralogy of the ores was studied by means of polished sections, X-ray diffraction and differential thermal analysis techniques. It is concluded from both field and laboratory evidence that these ores represent the metamorphosed equivalents of syngenetic manganese bearing sedimentsItem The Morphology and Transport of Mucus in Mammalian Airways.(1975) Andre William Wessels van AsThe mucociliary clearance mechanisms in mammalian pulmonary airways have been re-examined. In this investigation Wistar rats, housed both under specific pathogen free (SPF) and normal animal house conditions, were examined. An intact airway . system from the trachea down to the level of the terminal bronchioles was used. The airway preparation was rapidly isolated and examined under carefully controlled in vitro conditions. Specimens remained viable for at least 10 h. Mucociliary activity was observed through the intact bronchial wall with the aid of incident light. This function could be examined at all levels of the pulmonary tree in the same specimen. In contrast to the previously described presence of a continuous mucous bl~ket, the morphology of mucus in the airways of the rat has been shown to be discontinuous. Mucus is present as discrete particles of varying size. Under the light microscope these particles appeared to fall into three categories: droplets less than 4 μm in diameter; flakes 10-70 μm in diameter; and plaques which are conglomerations of droplets and flakes. Scanning electron microscopy reveals that droplets (i.e. single particles) may be as small as 0,5 μm and that composite particles made up of numerous aggregated droplets may be as small as 5 μm in diameter. Plaques are conglomerations of these particles. In the normal intrapulmonary airways only smaller particles are seen and are transported over the individual metachronal fields. In the larger extralobar airways these particles move together to be transported in well defined streams which may be up to 500 μm wide. These streams may follow a winding course up the trachea and more than one may be in operation at a time. Under conditions of hypersecretion such as occurs with chronic respiratory disease in rats (CRD) the number of particles increase peripherally and plaques may be found in small airways. The transport of mucus is however still intermittent and it never becomes confluent. Acute bronchitis results in wide-spread abnormalities of ciliary activity and mucus transport, which leads to total disorganisation of pulmonary clearance. "Chronic bronchitis" associated with CRD results in more organised abnormalities of mucociliary activity. Cilia may become inactive, reverse the .direction of their effective stroke, beat retrogradely, and exhibit abnormal beat patterns which result in impaired mucus clearance. Squamous metaplastic areas further impede mucus transport. In general mucus transport rates were found to be faster in rats with "chronic bronchitis" than SPF rats, provided that the extent of the damage to the mucous membrane was ( not too great in the "bronchitic" animal. This finding was confirmed by the examination of airway preparations approximately 19 h after the exposure to a charcoal aerosol. While significant amounts of charcoal were retained at the bifurcations of bronchi in SPF rats, most of the charcoal was cleared in "bronchitic rats'.'. The only areas where particles were seen were on bronchitic patches or on whirlpools. The findings of this study indicated that mucus was present in a discontinuous form, and that in both SPF and non-SPF animals no evidence for a mucous blanket was found.Item The Morphology and Transport of Mucus in Mammalian Airways.(1975) Andre William Wessels van AsThe mucociliary clearance mechanisms in mammalian pulmonary airways have been re-examined. In this investigation Wistar rats, housed both under specific pathogen system frfroeme (tShPeFt)raacnhdeanodrmowanl taonimthael lheovuelseofcotnhdeititoenrms, inwael rbe roexnacmhiionleeds . wAans uinsetadc. t airway The airway preparation was rapidly isolated and examined under carefully controlled in vitro conditions. Specimens remained viable for at least 10 h. Mucociliary activity was observed through the intact bronchial wall with the aid of incident light. This function could be examined at all levels of the pulmonary tree in the same specimen. In contrast to the previously described presence of a continuous mucous bl�ket, the morphology of mucus in the airways of the rat has been shown to be discontinuous. Mucus is present as discrete particles of varying size. Under the light microscope these particles appeared to fall into three categories: droplets less than 4 µm in diameter; flakes 10-70 µm in diameter; and plaques which are conglomerations of droplets and flakes. Scanning electron microscopy reveals that droplets (i.e. single particles) may be as small as 0,5 µm and that composite particles made up of numerous aggregated droplets may be as small as 5 µm in diameter. Plaques are conglomerations of these particles. In the normal intrapulmonary airways only smaller particles are seen and are transported over the individual metachronal fields. In the larger extralobar airways these particles move together to be transported in well defined streams which may be up to 500 µm wide. These streams may follow a winding course up the trachea and more than one may be in operation at a time. Under conditions of hypersecretion such as occurs with chronic respiratory disease in rats (CRD) the number of particles increase peripherally and plaques may be found in small airways. The transport of mucus is however still intermittent and it never be comes confluent. Acute bronchitis results in wide-spread abnormalities of ciliary activity and mucus transport, which leads to total disorganisation of pulmonary clearance. "Chronic bronchitis" associated with CRD results in more organised abnormalities of mucociliary activity. Cilia may become inactive, reverse the .direction of their effective stroke, beat retrogradely, and exhibit abnormal beat patterns which result in impaired mucus clearance. Squamous metaplastic areas further impede mucus transport. In general mucus transport rates were found to be faster in rats with "chronic bronchitis" than SPF rats, provided that the extent of the damage to the mucous membrane was not too great in the "bronchitic" animal. This finding was confirmed by the examination of airway preparations approximately 19 h after the exposure to a charcoal aerosol. While significant amounts of charcoal were retained at the bifurca tions of bronchi in SPF rats, most of the charcoal was cleared in "bronchitic rats .The only areas where particles were seen were on bronchitic patches or on whirlpools. The findings of this study indicated that mucus was present in a discontinuous form, and that in both SPF and non-SPF animals no evidence for a mucous blanket was found.Item Graham Newcater's orchestral works : case studies in the analysis of twelve-tone music(1984) Rorich MaryThe aim of this thesis has been four-fold, namely: i) to present an overview of twelve-tone theory and practice, particularly that practice that admits a background of traditional procedure; ii) to pinpoint the linguistic problems that twelve-tone music presents; iii) to suggest a style of analysis that makes coherent the linguistics of twelve-tone music; iv) to present in-depth case studies of four representative orchestral works of the South African composer, Graham Newcater, not only so as to make available analyses of his works, but also so as to provide practical exegeses of the theoretical problems listed in ii) and iii). Part I of this thesis is, therefore, synthetic rather than original. It sets out the premises of the serial principle, its structural implications, its historic-stylistic background, and problems in analysis. In Parts II and III various of Newcater's orchestral works are presented as case studies in the analysis of twelve-tone music with particular reference to the issues discussed in Part I. As is shown to be the case with Schoenberg in Part I, three out of four of Newcater's works are treated as examples of rhetoric that synthesizes serial principles and tonal syntax. It has therefore not been sufficient to analyze the sounding forms of the music as entirely the product of the various sets and their structural implications; on the contrary, it has been necessary both to justify the aesthetic validity of this synthesis and to examine the results. The First Symphony, the composer's first major work, and the Violin Concerto, one of a group of concertos written fairly recently, best illustrates Newcater's fusion of the twelve-tone and tonal worlds. The Variations de Timbres represents an attempt to create rhetoric more inherently compatible with the serial principle. Both in that it seems that this is the direction that Newcater is likely to take in the following decade, and in that the Variations undoubtedly represents one of Newcater's most valuable creative essays, its inclusion seems justified. The last work analyzed is the composer's Third Symphony. Its extensive treatment in Part III of this thesis is justified in that it clearly derives from the compositional idioms of all three works analyzed in Part II. Both in sound and in syntax, it is the most sophisticated of Newcater's orchestral works to date, and, in its assimilation of the influence of electronic music on live instrumental music, it also suggests a route that Newcater's compositional career might take. In that Newcater emerged, in his early career, as the first pioneering spirit in the use of the twelve-tone system in South Africa, in that his approach to twelve-tonalism is clearly derived from Schoenberg's, and in that, he possesses a compositional gift of undeniable strength, his works seemed to present an ideal vehicle for the concepts and issues set out in Part I of this thesis. No single approach or analytical method has been employed, although obviously the procedures explored by such specialists as George Perle and Milton Babbitt have provided the basis for set analysis. Beyond this, more traditionally 'descriptive' methods have been used, and the conceptual studies of Theodor Adorno and Leonard B . Meyer has provided invaluable points of reference. In that this thesis is concerned primarily with linguistics which the twelve-tone the theory produces, all analysis is largely concerned with pitch content. Where a reference to the other parameters is made, it is generally in the service of this aspect of Newcater's musicItem A critical analysis of the Bantu pelvis, with special reference to the female.(1945) Heyns, O. S.The student of pelvic morphology is compelled sooner or later to consider the two main functions of the girdle, those of weight-bearing and parturition. These functions Inevitably guide his Investigations. Comparatively little work has been done on the pelvic mechanics of erect posture. The evolution of man's erect posture, on the other hand, has been considered by Friedenthal (1910), Weidenreich (1913), Keith (1923), Morton (1926), Westenhofer (1929), and Reynolds (1931)* The last author's disappointing paper succeeds only in demonstrating the difficulty of establishing the principles underlying the orthopaedist's approach to the mechanics of man's posture.Item Abdominal decompression: a monograph(1963) Heyns, O. S.A short explanatory foreword to this monograph appears imperative. Abdominal decompression is the device offered for study and consideration to the reader of the following pages. If that reader accepts, for various cogent reasons, that abdominal decompression has certain effects upon the human organism— these being beneficial—and wishes to try its application, this is simple. Nothing is needed beyond the knowledge that the atmospheric pressure around the human trunk is to be reduced by one to three pounds a square inch of surface. The reader can then improvise some simple equipment and observe the effects of decompression upon him- or herself, upon another laboratory subject or on a patient who is pregnant, in labour, or suffering from menstrual pain or ordinary acute backache. The present work is but a record of the observable phenomena and their variations : matters which can be ascertained independently by the reader. As there is a wide range of application of the method and much time is needed to put possibilities to the test, an experimenter will be saved two years of work if he or she sets out equipped with the knowledge at present available.Item Evaluation of the South African army physical training programme: fitness attained and injuries sustained(1985) Gordon, Neil FarrylPhysical fitness has remained an essential requisite of modern-day armed forces. Despite considerable advances in the science of exercise training, the South African Army physical training programme has remained essentially unaltered for over a decade. Furthermore, it has been suggested that the efficacy of South African Army basic training centres might be limited by the injurious nature of the physical training modes used. The present 3-part investigation was therefore designed as an initial evaluation of the South African Army physical training programme in terms of both physical fitness attained and exertion-related injuries sustained. In Part I of this study, the effect of 1 year South African Army training on endurance fitness was investigated. The pre-military training maximal 02 consumption of 53.14 mg.kg-1.min-1 did not change significantly during the course of the study. In contrast, lactate turnpoint (m-g O2 ,kg- .min-J") and maximal treadmill performance time were moderately enhanced (7.5% and 8% increase, respectively, p<0.05) by the initial 10-week basic training programme. A further analysis of the results indicated that this endurance training effect was limited to the average and, in particular, the below-average fitness recruits. Although this could be regarded as an adequate situation, the effec= tiveness of the physical training was limited in that 17% of recruits were unable to complete the post-basic training exercise test as a result of exertion-related injuries; of these recruits more than 50% had initial below-average fitness levels. Furthermore, the observed beneficial effect of basic training on recruit endurance fitness levels was transient in nature, the values on completion of 1 year military training being essentially unaltered from those existing prior to military conscription. This preliminary assessment of the South African Army physical training programme demonstrates a need for the introduction of changes during and, in particular, after basic training. In Part II of this study, the effect of 1 year South African Army training on muscular strength, power, power- endurance, speed, and flexibility was investigated. When considering the entire study group, a significant enhance= ment by basic training was observed for the isokinetic muscular strength of the right elbow extensors alone (17% increase, p <0.05). Stratification of training responses on the basis of initial recruit fitness levels revealed significant (p<0.05) improvements with basic training for all measures of muscular strength, power, power-endurance, and speed, but not flexibility, in the below-average fitness recruits. In contrast, with the exception of elbow extensor strength, fitness levels of the average and above-average recruits were not improved by basic training. Furthermore, for all recruit fitness groups, values documented on completion of 1 year military training differed insignificantly from those recorded prior to military conscription. Although further research (aimed at assessing the physical requirements of various military work and emergency situations) is needed to evaluate the desirability of the observed selective enhancement of recruit fitness levels, it is evident from the present data that greater emphasis should, at the very least, be placed on flexibility training and physical conditioning after basic training. Finally, in Part III of this study the incidence and nature of exertion-related injuries sustained at a large South African Army basic training centre were studied. A total of 404 separate injuries were incurred by 359 of 947 recruits during the 10-week basic training cycle. Of these injuries, 18.3% were sustained with (Group 1) and 81.7% without (Group 2) an obvious sudden acute precipitating event. Exertion-related injuries were responsible for a loss of 2 711 recruit-days of basic training. While the knee sustained the largest number of Group 2 injuries, lower-leg injuries resulted in the greatest loss of basic training time. Fourty two separate radiographically confirmed stress fractures were incurred by 39 recruits, the incidence of recruits with stress fractures being 4.12%, a value considerably higher than that of the United States Army. These data leave little doubt that the injurious nature of the South African Army basic training programme studied is costly in terms of training time lost and may prohibit large numbers of recruits from deriving the optimum conditioning benefits.Item An analysis of fifth year Paediatric teaching(1987) Skapinker, ReneeMuch teaching in paediatrics is done at the patient's bedside. The clinical ward round should integrate all the pertinent features of the case. A prospective study was undertaken at the Johannesburg Hospital to evaluate such teaching. Twenty-two fifth year medical students and ten paediatric consultants were studied during the students1 first exposure to clinical paediatrics. Analysis of the teaching showed that there were significant differences between ideal objectives set by the Department, what was actually taught during the clinical ward round and what students perceived as having been taught. Futhermore, consultants defined more objectives for the teaching session when this was done prior to the tutorial than after the tutorial. The correlation between objectives considered taught by consultants and those perceived by students as having been taught, was poorer when consultants defined their teaching objectives before the tutorials compared with when consultants defined their objectives after the tutorials. These findings indicate unrealistic expectations in terms of what tutors are able to cover in a ward round when the objectives are pre-defined. Further analysis of the data revealed a bias towards objectives which were inappropriate for students with limited clinical experience.Item Sedimentological control of gold and uraninite mineralisation in the White Reef of the West Rand(1975) Steyn, L SThe primary objective of the study was to determine the controls of mineralization in the White Reef, which occurs at the base of the Bird Reef Stage of the Upper Witwatersrand System on the West Rand. It is a quartzite with scattered pebbles and occasional 'banket' conglomerates. The average gold content at 317 gm-cm per tonne is low, but uranium grade is amongst the highest on the Witwatersrand. In 1963 the author demonstrated some sedimentological properties of the Livingstone Reef are qualitatively related to gold content. More intensive studies have since confirmed the sedimentological control of gold mineralization. For instance, Pretorius (1974 a, 1975) recognizes a general fluvial fan geometry for the Witwatersrand reefs. However other factors, such as variations in environments, mechanisms of deposition, and behavior of the heavy minerals require further clarification; these form the main subject matter of this study. A pilot study established interrelationships between sedimentary features and ore grade. Follow-up work revealed systematic downslope changes. The reef was sampled on a systematic grid over the four West Rand mines. All pebbles were measured over complete reef sections. Measurements include 526 of reef thickness, 1 312 of crossbedding, 45 ripple marks, 2 of sand waves, 63 801 of pebble size and sorting, 63 761 for packing, 1 200 of fabric, 33 987 of composition, and 1 162 of shape and sphericity. Very large numbers of gold and uranium values, reef elevations, and thicknesses were compiled from records. The area investigated formed a subsiding part of a basin edge between granitic buttresses. Primary structures include the north-south Randfontein trough in the west, which controlled sedimentation from the Main Reef Stage onwards and the smaller north-east trending Witpoortjie trough. Additional control was exercised later by northeast and northwest-trending depressions. The major West Rand syncline running north-west, and the basin north of the Witpoortjie fault, are post-depositional features. The White Reef is comparable in geometry and sedimentological features to the Basal Reef (Sims, 1969) and generally conforms to the model of Pretorius (197 5). The subsiding Randfontein trough controlled the direction of major pay shoots, whilst smaller paystreaks formed along braided channels. The paleo-environment for the White Reef was that of a braided fluvial fan conforming to the model of Eynon and Walker (1974) for braided rivers. The distribution of depositional facies is related to fan geometry. (Abbreviations abstract)Item The problem of content in the theory of formal operations: Piaget and Vygotskii in the South African context(1984) Moll, IanThis thesis explores the extent to which Piaget falsely ignores the socio-economic contents of cognition in his account of formal operational thought. His biological conception of the origins of knowledge leads him to emphasize the structures of cognition, but Vygotskii's dialectical materialist psychology challenges this. It denies Piaget's separation of content from structure and accuses him of losing sight of the social construction of cognition. The thesis attempts to clarify the resultant dispute (drawing particularly on Buck-Morss' charge that Piaget has a socio-economic bias) and goes on to examine a concrete instance of the problem in the attainment of formal operations across different South African communities. Piaget's tasks showed that rural children exhibit significantly less formal operational ability than their urban peers and that within the latter group, township children have less abstract cognitive ability than their middle-class counterparts. Interviews showed that these tendencies correspond in each case to more emphasis on concrete activities, and less on abstract activities, in the everyday lifestyle of the former grouping. But this is in itself not enough to demonstrate a weakness in Piaget's theory. On a more abstract level, the final part of the thesis argues that the epistemology of genetic epistemology is ·inadequate because it leaves the very social nature of knowledge out of the picture. Taken together with concrete cross-cultural differences, this establishes a serious problem of content - a social "blindness'' - in Piaget's theory of formal operations.