The ecology of the red-billed quelea Quelea Quelea (Linnaeus) and other granivorous birds at Eastern Cape feedlots
- Authors: Whittington-Jones, Craig Alun
- Date: 2002
- Subjects: Quelea quelea -- South Africa -- Eastern Cape Granivores -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5618 , http://hdl.handle.net/10962/d1003286
- Description: Red-billed Quelea Quelea quelea have expanded their range in the Eastern Cape and now occur throughout the year in new areas. Recent changes in agricultural practice have probably been a contributing factor as flocks are larger than previously recorded and were more often associated with artificial food sources than natural grasses. Ringing and census data indicate that quelea have reduced movements during the non-breeding season and may display strong fidelity (over successive years) to dry season quarters with reliable food supplies. Although the recapture/recovery rate for quelea in the Eastern Cape (1.0-2.5%) was higher than the national average, it was still lower than expected and there may be considerable movement between nearby feeding sites. Some quelea breed locally, but most disperse during summer and their numbers at the feedlots were generally highest in winter and spring. The breeding season of quelea is later than other ploceids in the region and post-nuptial moult overlaps with winter. Replacement of primary wing feathers is relatively slow (124 days), and this is considered an adaptation to minimise disruption of flight capabilities and insulation. Significantly more quelea in the Eastern Cape have breeding plumage suffused with pink than in other southern African populations. However, during the non-breeding season there is apparently considerable intermixing between local populations and those from further north and the existence of a local sub-species is not supported. Seeds of two grass species, Echinochloa sp. and Urochloa panicoides, and two weed species, Amaranthus sp. and Chenopodium sp., were important in the diet of both quelea and Laughing Doves Streptopelia senegalensis. Maize comprised a large proportion of the diet of these species and losses at one ostrich feedlot were estimated at over R 17 000 in two years. Dependence on artificial food sources was generally greatest in winter and spring, but economically significant damage was not confined to this period. Alpha-chloralose showed good potential for reducing numbers of problem birds at livestock feedlots. However, the dynamic nature of problem bird populations favours a non-lethal management approach. Reduction of feed loss through manipulation of the ostrich ration could provide a relatively cheap and effective alternative to lethal control if applied appropriately.
- Full Text:
- Date Issued: 2002
Structural studies on some enterobacterial capsular antigens
- Authors: Whittaker, Darryl Vanstone
- Date: 1994
- Subjects: Bacterial antigens -- Analysis Antigens Enterobacteriaceae Escherichia coli Klebsiella
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3803 , http://hdl.handle.net/10962/d1003281
- Description: The investigations presented in this thesis form part of a systematic international effort to establish the structures of the capsules produced by the bacterial genera, Escherichia coli and Klebsiella (family enterobacteriaceae). These bacteria are of medical interest as they are opportunistic pathogens and are frequently responsible for serious infections in animals and man. Invasive strains are invariably surrounded by a structurally complex polysaccharide capsule which contributes to the organism's ability to attenuate non-specific host defence mechanisms or, in some instances, to completely prevent an immune response. A knowledge of the chemical composition and structure of the capsule is, therefore, of great value as it provides insight into the mechanisms involved in this process. The E. coli, in particular, have generated considerable interest as their capsules are more structurally diverse and cross-reactivity with other, more pathogenic bacteria has also been demonstrated. Accordingly, the structures of three previously unstudied E. coli K-antigens viz. those produced by serotypes 020:K83:H26, 020:K84:H26, and 09:K48:H9 have been established by chemical and spectroscopic means and are presented in this thesis. In addition, a reinvestigation of the structure of the capsule produced by Klebsiella K15 using a novel enzymatic approach was also undertaken and a revised structure is proposed . The E. coli K48 polysaccharide is of special interest as it was found to contain a new diacetamido trideoxy hexose hitherto unrecorded. A synthesis for this saccharide is also presented. Finally, the application of lithium dissolved in ethylenediamine for the degradation of amino sugar-containing polysaccharides was also investigated using the capsular polysaccharides produced by E. coli serotypes K38 and K84 as model compounds.
- Full Text:
- Date Issued: 1994
A framework for business leadership in Africa
- Authors: Whitley, Elwyn
- Date: 2014
- Subjects: Leadership -- Africa Success in business , Management -- Africa Business Industrial management -- Africa
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/45814 , vital:39219
- Description: In a fast moving, rapidly changing and highly competitive world the importance of strong leadership in both government and business cannot be over emphasised. The realisation that leadership is necessary for the organisation’s success and is key for the organisation’s survival (Alimo-Metcalfe and Alban- Metcalfe, 2008) is evident in the increasing focus on the concept over the last three to four decades. As the world becomes more of a ‘global village’ adapting to doing business in this new environment will require a leader who not only has the traditional skills set but also has the additional knowledge, skills and “mindset to navigate through the complexities brought on by moving beyond one's traditional borders” (Cohen, 2010. p. 3). This is of particular importance to Africa with the influx of foreign investors attracted by the growth opportunities that Africa offers, looking to expand their markets and in doing so imposing western norms and standards on local operations, in complex environments. Unfortunately Western leadership theories have not always been successful as Africans have found that in order to embrace Western ideals they need to relinquish some of their own beliefs. This highlights an opportunity to explore a possible hybrid leadership approach that harmonises the Western approach that is based on facts, logic and the nature of reality with the African humanistic orientation. The main aim of this study is to research the concept, principles, and characteristics of a small sample of business leaders in Africa in order to identify the factors that contribute to the leader’s success in a global business operating in Africa. By applying qualitative research methodology which includes an individual narrative written by each Managing Director, semistructured interviews and focus groups, a framework for business leadership in Africa was developed.
- Full Text:
- Date Issued: 2014
A petrological and mineralogical study of peridotite and eclogite xenoliths from certain kimberlite pipes
- Authors: Whitfield, Gavin
- Date: 1972
- Subjects: Petrology Peridotite Mineralogy Kimberlite Igneous rocks -- Inclusions Eclogite
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5044 , http://hdl.handle.net/10962/d1007690
- Description: Kimberlite, an ultrabasic diamond-bearing hypabyssal rock-type which has its origin in the Earth's upper mantle, characteristically contains rare, well-rounded xenoliths of peridotite and eclogite. These xenoliths, which undoubtedly originate from some considerable depth below the Earth's surface, possibly represent samples of upper mantle material. They have received much attention from earth scientists and numerous theories as to their origin have been proposed. Forty-two selected peridotite xenoliths from the Bultfontein, Wesselton, Dutoitspan and Roberts Victor kimberlite pipes of the Kimberley area, South Africa, and 24 eclogite xenoliths from the Roberts Victor pipe have been examined in detail using a variety of petrological and mineralogical techniques. The petrologic research comprises conventional petrographic studies, the determination of accurate modal compositions and the presentation of 22 new whole-rock chemical analyses, nine of which are of garnet peridotite, four of spinel peridotite and nine of eclogite, one being a diamondiferous specimen. Detailed mineralogical studies of the constituent minerals of the xenoliths comprises descriptive mineralogy, in most cases an estimation of the compositions of these minerals from the measurement of physical properties, X-ray powder diffraction data and the presentation of 21 new chemical analyses of pure mineral separates. This includes five analyses of clivine, five of orthopyroxene, eight of garnet, one of chrome diopside and two of omphacite. The results of the investigation have shown that the peridotites consist essentially of forsterite and enstatite with minor or trace amounts of one or more of pyrope-rich garnet, chrome diopside, chrome spinel, phlogopite and rarely graphite, and often exhibit features consistent with plastic movement and tectonic deformation. The peridotites are believed to be derived from an ultrabasic upper mantle, which is both chemioally and physically zoned. The eclogite xenoliths, which are composed mainly of pyrope-almandine garnet and omphacitic clinopyroxene and occasionally contain kyanite, corundum and diamond, are not samples of a primary eclogitic upper mantle nor the products of an eclogite fractionation related to kimberlite genesis. Chemically they are not typical of extrusive basalts and probably either represent pockets of partially fractionated basic magma trapped at mantle-level in an eclogite-stable environment or samples of high-grade crustal metamorphic eclogite accidentally incorporated into the Roberts Victor kimberlite.
- Full Text:
- Date Issued: 1972
Insecticide resistance in the blue tick, Boophilus Decoloratus Koch, in South Africa
- Authors: Whitehead, G B
- Date: 1960
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5897 , http://hdl.handle.net/10962/d1013426
- Description: The work described in this dissertation was undertaken in an attempt to obtain a better understanding of the causes and relationships of insecticide resistance in Blue Tick, Boophilus decoloratus Koch, which has become an acute problem in some localities of the country. The work was undertaken at the Research Department of African Explosives and Chemical Industries Limited over a period of six years from 1953 to 1958. An attempt has been made to keep up to date with the published literature on the various aspects of these investigations up until the end of 1958. Information gained from the literature subsequent to end of 1958 has been made use of but it has not been possible for a number of reasons to follow all recent developments in the various aspects of insecticide resistance published during 1959. In the execution of this work assistance has been obtained from colleagues better equipped in the field of organic chemistry, biochemistry and statistics, than the author. Where information so gained has been used it has been duly acknowledged. Considerable assistance was rendered by laboratory assistants who were responsible for performing the considerable amount of routine collection, breeding and testing of the biological material. The blue tick is not a convenient experimental organism for studies on insecticide resistance. Even with the best facilities the tick cannot be bred satisfactorily and in consequence all supplies had to be collected from naturally-occurring populations. Although this had decided advantages in some aspects of the work, a great deal of useful information might have been obtained if certain strains of ticks could have been maintained. The lack of a standard sensitive reference strain has been a considerable disadvantage which could not be overcome and which has influenced the manner in which this work has been carried out. Because the tick could not be bred artificially the work could only be undertaken with unfed larvae and fully engorged adult females . Larvae are extremely small and in consequence could only be handled in batches while the fully engorged female is sluggish and contains a large quantity of semi-digested mammalian blood which invariably interfered with chemical or biochemical studies.
- Full Text:
- Date Issued: 1960
"Glory is temporary, brain injury may be forever" : a neuropsychological study on the cumulative effects of sports-related concussive brain injury amongst Grade 12 school boy athletes
- Authors: Whitefield, Victoria Jane
- Date: 2007
- Subjects: Sports injuries Sports injuries -- Psychological aspects Brain damage Brain -- Concussion Neuropsychological tests Head -- Wounds and injuries -- Complications Head -- Wounds and injuries
- Language: English
- Type: Thesis , Doctoral , DSc
- Identifier: vital:3104 , http://hdl.handle.net/10962/d1004471
- Description: The study investigated the long-term neuropsychological effects of repetitive mild traumatic brain injury (MTBI) due to participation in a contact sport amongst South African final year male high school athletes (N=189). The sample was divided by sports affiliation (Contact n = 115; Non-Contact n = 74) and concussion history (2+ Concussion n = 43; 0 Concussion n = 108). Comparative subgroups were statistically equivalent for age, education and estimated IQ (P > 0.05), with the Contact sport groups having markedly higher incidences of concussion than controls (p < 0.000). Measures included the ImPACT Verbal and Visual Memory, Visuomotor Speed and Reaction Time Composites, Digit Symbol Substitution and Digit Symbol Incidental Recall (immediate and delayed), the ImPACT Symptom Scale and a Post-concussion Symptom (PCS) questionnaire. Independent t-tests on cognitive measures at pre-and post-season revealed a predominant trend of Contact and 2+ Concussion groups performing worse, although only ImPACT Reaction Time at pre-season reached significance (p = 0.014). PCS comparisons revealed an overwhelming tendency of enhanced symptoms for Contact and 2+ Concussion groups with total scores being significantly different in most instances at pre-and post-season. Fatigue and aggression were the symptoms most pervasively high for the Contact and 2+ Concussion groups. Dependent t-test analyses at pre- versus post-season, revealed significant practice effects for the Contact group, not in evidence for controls on ImPACT Visual Motor Speed and Digit Symbol Incidental Recall-Delayed. Overall the results imply the possible presence of lingering neurocognitive and symptomatic concussion sequelae amongst South African final year high school participants of a contact sport. The indications gain potency when understood against the background of (i) Brain Reserve Capacity threshold theory, and (ii) the known risk of Type II error in group MTBI research, that might result in under-emphasis of subtle effects and miscalculation of cost-benefit risks. Clinical implications, and the need for prospective case-based research to ratify the results of this predominantly cross-sectional study, are discussed.
- Full Text:
- Date Issued: 2007
The role of the queen in wax secretion and comb building in the Cape honeybee, Aps mellifera capensis (Escholtz)
- Authors: Whiffler, Lynne Anne
- Date: 1992
- Subjects: Honeybee Honey, Comb Beeswax Bee culture -- Queen rearing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5763 , http://hdl.handle.net/10962/d1005451
- Description: The role of the queen in wax secretion and comb building was studied in the the Cape honeybee, Apis mellifera capensis (Escholtz). The percentage of bees bearing wax and the amount of wax borne by these bees did not differ between the experiments. This meant that the queenless and queenright colonies had the potential to construct equal amounts of comb as the amounts of wax available for comb building was the same. Contrary to this prediction, queenright colonies constructed 8 times more comb than their queenless counterparts. Queenright Apis mellifera scutellata colonies constructed 4 times more comb than their queenless counterparts. The increased amount of 9-oxo-2-decanoic acid (90DA) in the A.m.capensis mandibular gland secretions could not alone account for this difference. In fact, A.m.capensis and A.m.scutellata colonies constructed similar amounts of comb when they were given their own queens or queens from the other race. Worker bees need to have direct contact with their queen for comb building to be enhanced. Even when the queen had her mandibular glands extirpated and tergite glands occluded large amounts of comb were constructed than when access to the queen was limited. Direct access to the head of a mated queen proved to be the stimulus enhancing comb building. No comb was constructed when the workers had access to the abdomen of the queen. Virgin queens did not stimulate comb building. The relatively large amounts of 90DA and 9HDA from the mandibular glands of Cape virgin queens had not influenced comb building. Worker sized cells were generally constructed. These cells were slightly smaller than those constructed by European honeybees, but were indicative of African bees. A few queen less colonies constructed cells that were of an intermediate drone and worker size. Four mandibular gland pneromones were measured by gas chromatography. No correlations between these pheromones and the comb construction measurements were found. It is unlikely that the mandibular gland pheromones are the only pheromones that stimulate comb building. Pheromones from other glands on the head may contribute towards the enhancement of comb building, and they are not present in virgin queens
- Full Text:
- Date Issued: 1992
Teachers’use of curriculum materials in Grade 3 Mathematics: A Case Study
- Authors: Whale, Susan Gaye
- Date: 2019
- Subjects: Mathematics -- Study and teaching (Primary) -- South Africa , Education -- curriculum innovation
- Language: English
- Type: Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10948/45591 , vital:38916
- Description: The study examines four curriculum documents with regards to curriculum facets, further interrogated through indicators for certain facets in order to ascertain whether the documents could be considered to be educative. Comparison is made with selected resources internationally. Observed episodes in four mathematics classes are interrogated with regards to teacher facets and concomitant indicators, to assess whether the tenets proposed in the written curriculum are translated into practice in the classrooms. The four Grade 3 teachers are interviewed about their views on the curriculum, their views on teaching and their views on their own agency in teaching mathematics. The teachers’ complete selected examples from a Mathematics Knowledge for Training (MKT) questionnaire and are engaged in conversations about iii their beliefs about mathematics and their confidence in both doing and teaching mathematics. The study identifies that the current CAPS curriculum documents focus on mathematical content almost exclusively and give minimal guidance concerning pedagogical content knowledge. The agency of teachers is not addressed. The study suggests a three-dimensional model of curriculum design that encompasses new educative curriculum materials; guidance on innovative teacher practices and direction towards new beliefs in teachers which could build agency and confidence. The concern that this study uncovers is that although the school and teachers were specifically chosen to minimise linguistic and social detractors, the intended curriculum does not appear to have been universally translated into
- Full Text:
- Date Issued: 2019
Friend or foe? : Resolving the status of the submerged macrophyte Myriophyllum spicatum L. (Haloragaceae) in southern Africa
- Authors: Weyl, Philip Sebastian Richard
- Date: 2015
- Subjects: Eurasian watermilfoil -- Africa, Southern , Eurasian watermilfoil -- Biological control
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5933 , http://hdl.handle.net/10962/d1017811
- Description: Myriophyllum spicatum L. (Haloragaceae), a submerged macrophyte, has been recorded in southern Africa since 1829, but only considered problematic as recently as 2005. In light of this, water resource managers are looking to control M. spicatum in southern African water bodies where it is problematic. Amongst control options available in South Africa, biological control is potentially the most cost effective and sustainable option for M. spicatum. However, there is a debate over the status of this plant in southern Africa with several authors reporting it as a native component of the aquatic ecosystem, while others argue that it has been introduced from Europe or Asia. The aim of this thesis is to use a multifaceted approach to resolve the status of M. spicatum, by studying aspects of its history, distribution, mechanisms of its adaptations, biotic interactions and genetic relationships in southern Africa. By resolving the status of this plant as either native or exotic, appropriate management strategies can be initiated for its control in situations where it is considered a problem.A review of the evidence collected from this thesis does not provide convincing evidence for the anthropogenic introduction of M. spicatum into southern Africa, and it is probably native to the region. The disjunct distribution as well as regular local extinctions of populations is relatively common for species that are at the edge of their range. The populations in southern Africa could thus be relics from a much wider distribution in the past. The development of local adaptations in southern Africa provides evidence for this and suggests that the populations have been isolated for a substantial period of time and have had a long evolutionary history in the region. The lack of specialist herbivores should suggest that M. spicatum has been introduced, but the complete lack of herbivores, including generalists, may weaken that argument. The lack of herbivores could be a result of something inherent in the plant, irrespective of a lack of evolutionary history in the region. The genetic evidence suggests a European origin, but is characteristic of a population (southern Africa as a whole) that has been isolated for a considerable time. Despite the findings of this research, M. spicatum is considered problematic in southern Africa and warrants control in certain systems. Whether or not biological control should be a component of the management strategy is open to further debate. The benefits in a southern African context may outweigh the risks, based on the specificity of the biological control agent proposed. However, the perceived negative impacts of M. spicatum are likely to be a symptom of a more serious underlying cause, such as nutrient loading and changes in land use patterns. Therefore the control of this native species is a water resource management issue and not a biological control issue.
- Full Text:
- Date Issued: 2015
The dynamics of a subtropical lake fishery in central Mozambique
- Authors: Weyl, Olaf L F
- Date: 1999
- Subjects: Fisheries -- Chicamba, Lake Fisheries -- Mozambique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5212 , http://hdl.handle.net/10962/d1004785
- Description: Fisheries in African reservoirs are typically multi -species and in most cases the fish resource is harvested with a number of gears. These characteristics complicate their management and the development of management procedures. Typically, long time series of data on catch and effort and length- or age-based catch are not available for these fisheries. This precludes the use of data intensive methods such as multi-species virtual population analysis. The principal aim of this thesis was to develop a management procedure for African reservoir fisheries that takes into account the pertinent biological characteristics of the target species and accounts for the multi-species and multi-gear irIteractions in such fisheries. An opportunity availed itself to undertake this work on Lake ChicaIllba (19°08'S 33°08'E) a man-made hydroelectric dam in subtropical Mozambique (Manica province). The specific objectives of this study were: to obtain locality specific biological parameters for the target species in Lake ChicaIllba; to assess gear utilisation trends in the fishery through the determination of gear-selectivity, catch rate and effort for each of the principal gears used in the fishery; to assess the fishery using traditional per-recruit models and to test existing and new per-recruit models that account for the multi-species and multi-gear nature of the fishery and to determine the adequacy of each of these approaches in the determination of suitable target reference point (TRP) exploitation rates. The three principal specIes in Lake Chicamba are the introduced largemouth bass, Micropterus salmoides, and two cichlids the Mozambique tilapia, Oreochromis mossambicus and the redbreast tilapia, Tilapia rendalli. Sectioned otoliths were used for age and growth determination. Marginal zone analysis showed that annulus formation in all three species occurred during winter. The maximum-recorded age was 5 years for M. salmoides, 16 years for T. rendalli and 10 years for O. mossambicus. Growth of the three species was best described by the 3 parameter von Bertalanffy growth model as ℓa = 465.51 (1 - e⁻ₑ·ₑ⁷⁵⁽a⁺⁰·⁰⁰⁹⁾ mm FL for M salmoides; ℓa = 238.74 (1 - e⁻⁰⁶³⁶⁽a⁺⁰·⁹⁰⁵⁾) mm TL for T. rendalli; and ℓa = 266.06 (1 - e⁻⁰⁷⁹⁰⁴⁽a⁺⁰·²⁶⁹⁾) mm TL for 0. mossambicus. Female T. rendalli attained 50%-maturity at 2.89 years, while O. mossambicus matured at 2.83 years and M. salmoides at 0.9 years. Both cichlid species spawned throughout summer while M. salmoides had a very short spawning season from August to September. The total annual mortality rate (Z) for M. salmoides in Lake Chicamba was 1.27 yr⁻¹, the mean empirical estimate of natural mortality (M) was 0.73 yr⁻¹, and fishing mortality (F) was calculated at 0.54 yr⁻¹. For T. rendalli Z = 0.31 yr⁻¹, M = 0.20 yr⁻¹, F = 0.11 yr⁻¹ and for 0. mossambicus Z= 0.62 yr⁻¹, M= 0.38 yr⁻¹, F= 0.24 yr⁻¹. The three species exhibited reproductive traits, which implied a high reliance of recruitment on spawner stock (nest guarding in T. rendalli and M. salmoides and mouthbrooding in O. mossambicus). For this reason it was decided that the cichlid fisheries should be managed using TRPs which maintained the spawner biomass-per-recruit at 50% (FSB50) of pristine levels. However, based on good evidence it was hypothesised that the high rate of fishing mortality helped to maintain the fast growth rate of M. salmoides. It was, therefore, decided to manage this species at a TRP of F SB40. The three most important fishing sectors were the gill-net, seine-net and hook-and-line fisheries. The total catch for 1996 was 223 t. The gill nets selected all three species at a size/age approximating 50%-maturity while the seine-net and hook-and-line fisheries selected mainly juvenile fishes. There was strong evidence to suggest that seine net fishing also disrupted spawning. It was shown that the 'traditional' single-species per-recruit models were unsuitable to assess multi-species and multi-gear reservoir fisheries. Since existing multi-species/multifishery yield-per-recruit models were not capable of defining FsB(x) TRPs, a new multispecies/ multi-fishery spawner-biomass-per-recruit approach was developed. This approach allowed for the simulation of the response of spawner biomass-per-recruit to changes in effort in the three fishery sectors, simultaneously. The models showed that the spawner biomass-per-recruit, at current effort levels, was higher than the suggested TRP for the three species. However, it was shown that an increase of 10% in current total effort would reduce spawner biomass-per-recruit to below the recommended TRP levels. With the closure of the seine-net fishery, gill-net effort could be increased to 338 fishers (340 for management purposes) and effort in the hook-and-line fishery could be increased by 30% before the TRP was reached. To maintain the fish stocks above TRP levels, effort control was considered to be the most effective management method. The main recommendations for Lake Chicamba were to close the seine-net fishery, to limit the gill-net fishery to 340 fishers (using 137-m long x 3-m deep gill nets) and to maintain the open access nature of the hook-and-line fishery. The multi-species/multi-fishery per-recruit approach allows for the meaningful simulation of various scenarios and provides relatively robust management options. In the absence of long time series of effort and age- or length-based catch data, this approach was considered as the most suitable assessment method for multi-species/multi-gear African reservoir fisheries.
- Full Text:
- Date Issued: 1999
The Management of learners who experience barriers to learning in mainstream Primary Schools in the Eastern Cape
- Authors: Wevers, Nicolaas Ebenhaezer Jacobus
- Date: 2012
- Subjects: Inclusive education -- South Africa -- Eastern Cape , Learning disabilities -- South Africa -- Eastern Cape , Mainstreaming in education -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9453 , http://hdl.handle.net/10948/d1015186
- Description: Much emphasis has been placed on democracy, equality and human rights since the dawn of the democratic South Africa in 1994. Efforts to align the South African education system with the democratic principles of the Constitution, not only in terms of eradicating past racial divides, but also in terms of accessibility to learners who experience barriers to learning are eminent. The South African Government issued various policies to ensure quality, equitable and accessible education for all, irrespective of ability. Theoretically, no learner should therefore being discriminated against on any basis. In practice, however, thousands of learners, especially those who experience barriers to learning are denied the opportunity to receive meaningful development opportunities in many mainstream primary schools, resulting in their early drop out from school without having acquired the basic skills and knowledge to become self sustainable members of their communities. With the adoption of Bronfenbrenner’s ecological model as theoretical framework for this study, the primary aim of this qualitative investigation was to investigate and describe how effective learners who experience barriers to learning are managed in mainstream primary schools and to develop a framework for the creation of more sustainable management systems to ensure that the needs of all learners are met. The findings of the empirical investigation revealed that most learners who experience barriers to learning are currently not managed effectively in mainstream primary schools due to factors situated across the whole education system, to the detriment of learners who experience barriers to learning. Based on the findings of the empirical investigation, this study proposes a framework which will ensure the effective management of learners who experience barriers to learning in mainstream primary schools. The framework include recommendations to be implemented across all layers of the ecological system.
- Full Text:
- Date Issued: 2012
A Model for Crime Management in Smart Cities
- Authors: Westraadt, Lindsay
- Date: 2019
- Subjects: Smart cities , Computer networks -- security measures
- Language: English
- Type: Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10948/45635 , vital:38922
- Description: The main research problem addressed in this study is that South African cities are not effectively integrating and utilising available, and rapidly emerging smart city data sources for planning and management. To this end, it was proposed that a predictive model, that assimilates data from traditionally isolated management silos, could be developed for prediction and simulation at the system-of-systems level. As proof of concept, the study focused on only one aspect of smart cities, namely crime management. Subsequently, the main objective of this study was to develop and evaluate a predictive model for crime management in smart cities that effectively integrated data from traditionally isolated management silos. The Design Science Research process was followed to develop and evaluate a prototype model. The practical contributions of this study was the development of a prototype model for integrated decision-making in smart cities, and the associated guidelines for the implementation of the developed modelling approach within the South African IDP context. Theoretically, this work contributed towards the development of a modelling paradigm for effective integrated decision-making in smart cities. This work also contributed towards developing strategic-level predictive policing tools aimed at proactively meeting community needs, and contributed to the body of knowledge regarding complex systems modelling.
- Full Text:
- Date Issued: 2019
Thermal degradation of diamond compacts: a TEM investigation
- Authors: Westraadt, Johan Ewald
- Date: 2011
- Subjects: Materials -- Thermal properties Chemical weathering
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/10829 , vital:26827
- Description: Diamond compacts consist of fine diamond grains bonded together by using high pressure and high temperature. In this study transmission electron microscopy (TEM)was used to study thermal degradation of diamond compacts. Three different types of diamond compacts – namely cobalt polycrystalline diamond (PCD), calcium carbonate PCD, and diamond-SiC composites – were investigated with TEM to understand the processes that occur during synthesis. These compacts were then heated in inert atmospheres and the chemical changes studied with TEM. It was found that PCD, using cobalt as a bonding agent, will degrade after exposure to temperatures above 750ºC. The cobalt pools contain tungsten in solid solution. During heat treatment above 700ºC the solid solution tungsten combines with cobalt and dissolved carbon to form η-phase particles at the cobalt/diamond interface. At higher temperatures or insufficient tungsten levels the rate of dissolved carbon, into the cobalt pool, is too high and the excess carbon will form as graphite in the cobalt pool. Increased levels of solid solution tungsten, in the cobalt, is expected to delay the onset of graphitization in the diamond compact, thereby increasing the thermal stability of the diamond compact. Non-metallic PCD using calcium carbonate as a bonding agent was successfully sintered in this study. TEM revealed similar micro-structural features as in cobalt based PCD. No signs of thermal degradation were found after exposure to 1200ºC in vacuum for this PCD. Contaminants introduced during processing prevented a detailed study of the binder in this system. The effect of substitutional metal atoms and plastic deformation of diamond on the thermal stability of diamond-SiC composites were investigated. A piston cylinder press was developed and used to synthesize diamond-SiC composites with different levels of plastically deformed diamond. It was concluded that substitutional metal atoms and plastic deformation of diamond grains play no role in the thermal degradation of diamond compacts at 750ºC. The thermal degradation of cobalt PCD is therefore completely determined by the cobalt/diamond interaction at 750ºC.
- Full Text:
- Date Issued: 2011
An investigation of the key mechanisms that promote whole school development in a secondary school pilot project context
- Authors: Westraad, Susan Fiona
- Date: 2007
- Subjects: Education -- South Africa Education, Secondary -- South Africa Education and state -- South Africa School improvement programs -- South Africa Educational change -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1414 , http://hdl.handle.net/10962/d1003291
- Description: Providing relevant and quality schooling for all South African learners is the paramount goal of the South African National Department of Education. South Africa 's historical and current socio-economic contexts provide many challenges for both the Department of Education and schools in this endeavour to provide quality teaching and learning. These challenges impact directly and indirectly on what happens in the classroom. Since 1994 a plethora of education and training policy has been introduced in South Africa to redress historical imbalances; to introduce a new education and training framework and approach; and to provide guidelines, principles and procedures for addressing some of the challenges that impact on schools. The National Whole School Evaluation Policy provides the legislative framework for the establishment of a quality assurance process in South African schools based on accountability and support. The subsequent Integrated Quality Management System attempts to provide a framework for integrating school evaluation and performance measurement. Policy frameworks are in place to guide quality assurance and school improvement, however, the reality of implementing this at a grass roots level is particularly challenging. The General Motors (GM) South Africa Foundation, a non-governmental development organisation, established by General Motors (GM) South Africa, commenced with the piloting the Learning Schools Initiative to investigate some of the challenges of whole school development and evaluation. This research documents the Learning Schools Initiative's intervention with the initial two pilot secondary schools situated in Port Elizabeth (Nelson Mandela Bay) over a four-year period. It reviews the relevant school reform and school development literature and adopts a critical realist evaluative research approach to investigate the key mechanisms that promote whole school development and change in this context. In keeping with this approach, the results of the research are analysed and discussed within a context-menchanism-outcome configuration that involves the identification of the key mechanisms that bring about desired outcome/s in a specific context. Seven key generative mechanisms are identified as critical at a school and classroom level (i) school culture, (ii) school structures, (iii) effective leadership and management, (iv) personal growth and meaning, (v) restoration of relationships, (vi) professional development of educators, and development of capacity to work together, and (vii) support and accountability. The need to structure school development interventions around the triggering of identified key mechanisms is also identified as an important overarching mechanism. Suggestions are made for further research required to facilitate a deeper understanding of how to bring about meaningful change that results in quality teaching and learning in South African schools.
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- Date Issued: 2007
The emergence and expression of teachers’ identities in teaching foundation phase mathematics
- Authors: Westaway, Lise
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/7000 , vital:21208
- Description: The assertion that learner performance in South African schools is in crisis may be cliched but it is certainly true. The majority of learners in the schooling system are not achieving the required outcomes, particularly in language and mathematics. I use the underperformance of learners in mathematics as the impetus for my research which seeks to understand how teachers’ identities emerge and are expressed in teaching Foundation Phase mathematics. The research contributes to an emerging scholarship that strives to explain underperformance and quality in mathematics classrooms beyond structuralist theorising. Recently research, particularly in South Africa, has begun to look more closely at who the teacher is and how the teacher is key in understanding what happens in the mathematics classroom. This emerging scholarship focuses on teacher identities. Research that foregrounds teacher identities within the field of mathematics education tends to be situated within a social constructionist orientation, which assumes that our knowledge of self and the world comes from our interactions with people and not some ‘objective’ reality (Berger & Luckman, 1966). Such a perspective appears to conflate questions of how we know something with what is. In other words, it elides structure and agency, thereby making research that seeks to examine the interplay between the two in the formation and expression of teachers’ identities, practically impossible. It is for this reason, as well as the need to move beyond the hermeneutic, that my research draws on Margaret Archer’s (1995, 1996, 2000) social realist framework. Social realism posits a relativist epistemology but a realist ontology. It is underpinned by the notion of a stratified reality with structural mechanisms giving rise to events in the world whether we experience them or not. It is only through the (inter)actions of persons that such mechanisms have the tendential power to constrain or enable the projects of persons. As such, my research seeks to identify the structural and agential mechanisms that give rise to teachers’ identities and how these identities are expressed in teaching Foundation Phase mathematics. In my research, teacher identity refers to the manner in which teachers express their social roles as teachers. In the research I use a case study methodology. I provide rich data on four isiXhosa teachers teaching in low socio-economic status schools. This data is gleaned through interviews and classroom based observations which were recorded as field notes and video transcripts. Analysis of the data occurs through the thought processes of abduction and retroduction (Danermark, Ekstrom, Jakobsen, & Karlsson, 2002). These thought process enable me to (re)describe and (re)contextualise the object of study. Through the process of asking transfactual questions I identify the structural, cultural and agential mechanisms giving rise to teachers’ identities and their expression in teaching foundation phase mathematics. There are three significant findings in my research. Firstly, research that attempts to understand the emergence and expression of teacher identities should consider their broad contextual realities. The historical, economic, social and political contexts in which the teachers are born and live, influences their sense of self, personal identities and social identities (teacher identities) and as such, influences their decision to become teachers and how they express their roles as teachers of Foundation Phase mathematics. Secondly, my research suggests that teachers’ mode of reflexivity is key to understanding the decisions that they make in the classroom and how they deal with the structures that condition the manner in which they express their roles as teachers. Thirdly, collective agency is necessary to bring about change in the way in which teachers express their roles in teaching Foundation Phase mathematics. My research produces new knowledge by examining the interplay of structure, culture and agency in the constitution of foundation phase teachers’ identities and their expression in teaching foundation phase mathematics. I use a social realist orientation to examine this interplay and provide an understanding of the mechanisms giving rise to the phenomenon under consideration. In this way I contribute to the extensive research on learner underperformance by focusing more explicitly on who the teacher is in the classroom.
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- Date Issued: 2017
Bare life in the Bantustans (of the Eastern Cape): re-membering the centinnial South African nation-state
- Authors: Westaway, Ashley
- Date: 2009
- Subjects: Democracy -- South Africa , Homelands (South Africa) , Apartheid -- South Africa , Right of property -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (History)
- Identifier: vital:11535 , http://hdl.handle.net/10353/149 , Democracy -- South Africa , Homelands (South Africa) , Apartheid -- South Africa , Right of property -- South Africa
- Description: This thesis argues that 1994 did not mark a point of absolute discontinuity in the history of South Africa. More specifically, it asserts that 1994 did not signal the end of segregationism; instead of democracy leading to national integration, the Bantustans are still governed and managed differently from the rest of the country. Consequently, it is no surprise that they remain mired in pervasive, debilitating poverty fifteen years after 1994. In insisting that contemporary South Africa is old (rather than new), the thesis seeks to make a contribution to political struggles that aim to bring to an end the segregationist past-in-the-present. The thesis is arranged in seven chapters. The first chapter considers the crisis that has engulfed South Africa historiography since 1994. It traces the roots of the crisis back to some of the fundamentals of the discipline of history, such as empiricism, neutrality and historicism. It suggests that the way to end the crisis, to re-assert the relevance of history, is for historians to re-invoke the practice of producing histories of the present, in an interested, deliberate manner. Chapter 2 narrows down the focus of the thesis to (past and present) property. It suggests that instead of understanding the constitutional protection of property rights and installation of a restitution process as the product of a compromise between adversarial negotiators, these outcomes are more correctly understood as emanating from consensus. The third chapter outlines the implementation of the restitution programme from 1994 to 2008. The productive value of restitution over this period is found not in what it has delivered to the claimants (supposedly the beneficiaries of the programme), but rather in its discursive effects related to citizenship in the new South Africa. Chapter 4 considers the exclusion of dispossession that was implemented in the Bantustans from the restitution programme. It argues that this decision was not an oversight on the part of the post-1994 government. Instead it was consistent with all other key policy decisions taken in the recent period. The Bantustans have been treated differently from the rest of South Africa; they have been deliberately under-developed, fabricated as welfare zones, and subjected to arbitrary customary rule. Whereas Chapters 2 to 4 look at the production of historical truth on the side of domination, Chapter 6 and 7 consider production on the side of resistance. Specifically, they describe and analyse the attempts of an NGO to establish the truths of betterment as dispossession, and post-1994 prejudice against the victims of betterment dispossession. They serve as case studies of third party-led processes that seek to produce truth-effects from within a prevailing truth regime. The final chapter attempts to bring many of the threads that weave through the thesis together, by means of a critical consideration of human rights discourse. The chapter calls on intellectuals to establish truths in relation to the history of ongoing human wrongs in South Africa (as opposed to the rainbow narrative of human rights) Finally, the thesis includes a postscript, comprising technical summaries of each of the chapters.
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- Date Issued: 2009
White women writing white : a study of identity and representation in (post-)apartheid literatures of South Africa
- Authors: West, Mary Eileen
- Date: 2006
- Subjects: South African fiction (English) -- History and criticism , Identity (Psychology)
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8443 , http://hdl.handle.net/10948/442 , South African fiction (English) -- History and criticism , Identity (Psychology)
- Description: This thesis examines aspects of identity and representation using contemporary theories and definitions emerging out of a growing body of work known as whiteness studies. The condition of whiteness as it continues to inform identity politics in post-apartheid South Africa is explored in an analysis of selected texts written by white women, to demonstrate the ways in which whiteness continues to suggest normativity. In reading a representative selection of literatures produced in contemporary South Africa by white women writers, this study aims to illustrate the ambivalence apparent in the interstitial manifestations of emergent reconciliatory gestures that are at odds with residual traces of superiority. A sampling of disparate texts is examined to explore the representations of race and belonging in post-apartheid South Africa in the light of contemporary theories of whiteness which posit it as a powerful and invisible identification. The analysis attempts to plot a continuum from writers who are least, through to those who are most, aware of whiteness as a cultural construct and of their own positionality in relation to the discursive dynamics that inform South African racial politics. A contextualising overview of the terrain of whiteness studies is provided in Chapter One, marking the ideological and theoretical affiliations of this project, and foregrounding the construction of whiteness as an imagined identity in contemporary cultural criticism. It also provides a justification for the selection of the textual material under scrutiny. Chapter Two explores a genre that has been identified as a growing trend in South African fiction: the production of pulp fiction written by white middle-class women. Two such texts are the focus of this chapter, namely, Pamela Jooste’s People like Ourselves (2004) and Susan Mann’s One Tongue Singing (2005), and the complicities and clichés that are characteristic of popular literature are examined. Antjie Krog’s A Change of Tongue (2003) is the focus of Chapter Three. It is examined as a book offering the writer’s personal response to the difficulties of transformation within the first decade of South African democracy. Krog confronts her own defensiveness, her sense of normalcy, and her sense of alienation in relation to multiple encounters with different people. Chapter Four focuses on the journalism of Marianne Thamm. Her role as columnist for the popular women’s magazine, Fairlady is explored, particularly in relation to the inclusion of a contending voice writing against the general tenets of Fairlady. Thamm’s critique of the mores governing bourgeois white womanhood is read in relation to her role as officially sanctioned Court Jester. Her Fairlady columns have been collected in Mental Floss (2002) but the analysis includes selected columns from 2003 to 2005. Echo Location: A Guide to Sea Point for Residents and Visitors (1998) by Karen Press is the focus of Chapter Five. Her work is read as examining a white South African crisis of belonging in relation to the implications of mapping the co-ordinates of whiteness in South Africa. Chapter Six offers a reading of four short stories, written by Nadine Gordimer and Marlene van Niekerk. These stories are juxtaposed to trace an anxious impasse in white responses to suburbia, the place of enactment of white bourgeois mores, which both writers interrogate.
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- Date Issued: 2006
The development of best practice guidelines for the contingency management of health-related absenteeism in the motor manufacturing industry
- Authors: Werner, Amanda
- Date: 2005
- Subjects: Sick leave , Absenteeism (Labor) , Contingency theory (Management) , Automobile industry and trade -- South Africa
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9379 , http://hdl.handle.net/10948/160 , Sick leave , Absenteeism (Labor) , Contingency theory (Management) , Automobile industry and trade -- South Africa
- Description: The research problem in this study was to identify best practices for the contingency management of health-related absenteeism. To achieve this goal, the following actions were taken: A literature study was conducted to identify the scope and impact of health-related absenteeism on organisations and the legal parameters within which health-related absenteeism should be managed. A literature study was also conducted to identify strategies to prevent and reduce health-related absenteeism and strategies to ensure the continuous provision of products and services in periods of high absenteeism. The theoretical study focused on the management of absenteeism, wellness, ill-health/mental problems and HIV/AIDS, as well as contingency strategies aimed at maintaining production and service provision. iii The findings from the literature study were integrated into a model of best practices for the contingency management of health-related absenteeism. This model was used as a basis for the development of a survey questionnaire to determine whether senior human resources practitioners, occupational health practitioners or line managers, who were responsible for the management of health-related absenteeism in organisations, agreed with the best practice guidelines developed in the study. The survey was conducted in the motor and motor component industry in the Nelson Mandela Metropolitan Municipality and Buffalo City Metropole. The empirical results from the study showed a strong concurrence with the best practices guidelines developed in the study, with the exception of the strategies aimed at maintaining undisrupted production and service provision during periods of high absenteeism. In particular, disagreement was shown with regard to alternative work arrangements such as flexible work-hours, a compressed workweek, telecommuting and job-sharing. Absenteeism, in general, is an issue that organisations are challenged with on a daily basis. The proliferation of various diseases, specifically HIV/AIDS, is contributing to this problem. An integrated and strategic approach is required to deal effectively and constructively with the immediate and expected future impact of health-related issues on absenteeism. Organisations could use the best practices guidelines, identified in this study, as a mechanism to benchmark how well they manage health-related absenteeism
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- Date Issued: 2005
Identification and characterization of novel oncology related platinum complexes using chromatographic and mass spectrometric techniques
- Authors: Wentzel, Mauritz
- Date: 2008
- Subjects: Chromatographic analysis , Spectrum analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10310 , http://hdl.handle.net/10948/715 , Chromatographic analysis , Spectrum analysis
- Description: In this thesis mass spectral and chromatographic techniques were developed and applied to identify and characterise numerous novel platinum(II) and (IV) compounds designed as anticancer agents. In a novel method for the synthesis of cis-oxalato(trans- -1,2- cyclohexanediamine)platinum(II) or oxaliplatin these techniques could be applied to differentiate between the molecular complex and the autoionised analogue (viz. Ptdach2 2+Ptox2 2-). In another novel synthetic method for the same compound the ligand exchange reactions at various temperatures could be investigated and kinetic curves obtained served to illuminate the chemistry involved, indicating the role of small amounts of water in the essentially non-aqueous solvent systems dmf and isoamyl alcohol respectively. These allowed ligand exchange without resulting in hydrolyses even up to 85°C. The ionisation rate of divalent platinum halide complexes was determined for various amine ligands as well as N-S chelate ligands. A comparison of these could suggest why N-S complexes have poor anticancer action. Ionisation was not only studied for neutral molecular species but also for monocationic ones. Relationships could be found with stereochemical aspects of the chelates used. By investigating results of EV-CAD studies thermodynamic data could be obtained which indicated that bond strength decreases from chloro to iodo analogues although extent of ionisation in aqueous solution, i.e kinetic stability, is the reverse. Products formed by the reaction of NO2 gas with Platinum(II) compounds could be identified and separated which greatly contributed to the understanding of the chemistry involved in the formation of mononitro platinum(IV) complexes. Some of these proved to have exceptional anticancer properties. Studies of the interaction of thiol containing biomolecules were performed as a function of time. The results contributed to the understanding of the action of the anticancer agents.
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- Date Issued: 2008
An investigation of learners' perceptions of homework in relation to the learning of mathematics : case studies in the northern townships of Port Elizabeth
- Authors: Wendt, Gabriele Erika
- Date: 2000
- Subjects: Homework -- South Africa -- Port Elizabeth Mathematics -- Study and teaching -- South Africa -- Port Elizabeth Mathematics -- Study and teaching -- South Africa -- Case studies Education and state -- South Africa Education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1635 , http://hdl.handle.net/10962/d1003517
- Description: Matriculation pass rates in South Africa, especially in Mathematics, have been poor. The literature and personal experience suggests that a problem with homework may be a factor in this. In order to discover how Port Elizabeth learners from ex-DET schools perceived and experienced Mathematics homework, and the nature of such homework, ten case studies of Grade 11 learners were done. While conducting and analyzing the case studies, a pattern emerged from the findings, which together with some new questions, needed to be explored on a larger sample population. In order to do this and to be able to generalize the findings, four follow-up studies in the form of surveys on Mathematics homework were conducted at nine schools. These studies involved a learner questionnaire, a teacher questionnaire, the timing of learners as they did set Mathematical problems and the analysis of common errors made by the learners while doing the problems. The findings revealed that learners received too little homework too infrequently and did it inefficiently and ineffectively. The learners worked too slowly, did not complete the homework, left out the difficult problems and made numerous unnecessary mistakes. However, most of the learners claimed to have enough time available to do their homework and spent approximately one hour on Mathematics homework when it had been assigned. Many of the misconceptions and the resultant errors originated from work that should have been well covered in previous grades. However, parts of the syllabi were omitted in previous grades and completion of the syllabus and homework was only seriously considered in Grade 12. Some implications of the findings for educational practice and further research are discussed.
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- Date Issued: 2000