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Psychological and emotional effects of repeated exposure to violent crimes on victims residing in a high crime community in Nelson Mandela Metropolitan in the Eastern Cape

  • Authors: De Klerk, Ulricha
  • Date: 2020
  • Subjects: Post-traumatic stress disorder
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/46413 , vital:39582
  • Description: Traumatic Stress Disorder (PTSD). While the literature provides detailed and comprehensive approaches and counselling modalities to working with clients who experience traumatic events, there is not much evidence on the experiences of individuals who reside in high crime communities. It follows, that the psychological and emotional experiences, as well as needs of such individuals may present with specific requirements from the therapeutic alliance. This study aimed to explore the psychological and emotional effects of repeated exposure to high crime and violence and the implications this posed to traumatic experiences. The study further aimed to develop a set of guidelines that can be drawn upon when working therapeutically with clients who reside in high crime communities. The study draws on a qualitative methodology and 17 participants were interviewed. The transcripts were analysed using thematic analysis and five themes were identified, relevant to the aims and objectives that were set. The findings suggest that the psychological and emotional experiences of individuals who reside in high crime communities, is experienced at a more heightened and prolonged period, thus making the psychotherapeutic intervention employed, more specific. To this effect, the guidelines developed provide specific strategies and approaches thatwere developed based on the themes identified and verified by a panel of psychological experts. The study contributes to the field of trauma, counselling and violence, in that it focuses on an area of trauma that has not been adequately focused on withinthe South African context, as well as in global contexts.
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  • Date Issued: 2020

Quantifying ecosystem restoration recovery and restoration practice following the biological control of invasive alien macrophytes in Southern Africa

  • Authors: Motitsoe, Samuel Nkopane
  • Date: 2020
  • Subjects: Salvinia molesta , Ceratophyllum demersum , Nymphaea mexicana , Invasive plants -- Biological control -- South Africa , Aquatic weeds -- Biological control -- South Africa , Restoration monitoring (Ecology) -- South Africa , Biolotical invasions -- Environmental aspects
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/167519 , vital:41488
  • Description: Invasive alien aquatic plants (IAAP) species are known to have deleterious effects on the freshwater ecosystems they invade. This includes both socio-economic and ecologically important ecosystem goods and services. Thus, IAAP species are declared a serious threat, second only to habitat modification for causing a loss of aquatic biodiversity. Three control methods have been widely applied to control IAAP species invasion globally; mechanical, chemical and biological control. Both mechanical and chemical control methods are considered short-term and expensive, whereas biological control methods are regarded an effective and long-term solution for IAAP species control at the landscape level. But, little is known of the ecological recovery following the biological control of IAAP species, with mechanical control known to have had mixed success and chemical control to have non-targeted effects on aquatic ecosystems, causing harm to wildlife and human well-being. Biological control practitioners measure the success of biological control based on: (1) the biological control agents’ establishment and the negative impacts they impose on the targeted weed; and (2) the weeds biomass reduction and an increase in native macrophytes species. Arguably, measures of biological control success have been subjective and variable across the globe. Although some field studies have demonstrated biological control success to have positive socio-economic returns, there is little literature on ecological benefits. Furthermore, there is limited understanding on ecosystem recovery and possible restoration efforts following the biological control IAAP species, as compared to alien weeds in terrestrial and riparian ecosystems. Thus, this thesis aimed to quantify the ecological recovery i.e. aquatic biodiversity, ecosystem processes and trophic interactions following the management of Salvinia molesta in freshwater ecosystems. The research employed a suite of Before-After Control-Impact mesocosm and field studies to investigate the response of aquatic microalgae, macroinvertebrates and their interactions (food web structure and function) during S. molesta infestation and after mechanical and biological control. The mesocosm experiment (Before invasion, During invasion & After control) showed that both aquatic microalgae and macroinvertebrate diversity indices were reliable biological indicators of S. molesta ecological impacts and recovery following control. The restored treatment (100% S. molesta cover + biological control agents), demonstrated complete aquatic microalgae and macroinvertebrate recovery following biological control, similar to the control treatment (open water), where the degraded/impacted treatment (100% S. molesta cover with no biological control agents) showed a drastic decline in aquatic biodiversity and a complete shift in aquatic biota assemblage structure. Thus, the biological control effort by Cyrtobagous salviniae, the biological control agent for S. molesta, assisted in the recovery of aquatic biota following successful biological control. The field study (four field sites, two sites controlled mechanically and two biologically) investigated water quality, aquatic biodiversity and community trophic interactions (aquatic food web) “before and after” S. molesta control. The study showed a drastic decline in aquatic biodiversity (with three sites showing no record of aquatic macroinvertebrates, thus no biotic interactions during infestation) and poor water quality due to the shade-effect (light barrier due to floating S. molesta mats on the water surface) during the “before” S. molesta control phase. However, following both mechanical and biological control (“after” S. molesta control phase), there was a significant shift in abiotic and biotic ecosystem characteristics as compared to the “before” S. molesta control phase. Thus, rapid ecosystem recovery was apparent as a result of aquatic microalgae and macroinvertebrates recolonisation. Sites showed a normal functioning ecosystem where improved water quality, increased biodiversity, productivity and trophic interactions, was indicative of the return of biologically and functionally important species which were lost during the “before” S. molesta phase. Although the clear water state showed positive outcomes at Westlake River, these were short lived when the system was dominated by a cosmopolitan submerged Ceratophyllum demersum, and later replaced by a floating-leaved emergent IAAP Nymphaea mexicana. Each state was responsible for a significant shift in both biotic and abiotic characteristics, affirming macrophyte abilities to influence aquatic environments structure and functions. Furthermore, this event showed a clear example of a secondary invasion. Thus, a holistic IAAP species management strategy is necessary to restore previously invaded ecosystems and prevent subsequent secondary invasion and ecosystem degradation. In conclusion, the S. molesta shade-effect like any other free-floating IAAP species, was identified as the main degrading factor and responsible for water quality reduction, loss of aquatic diversity and shift in aquatic biota assemblage structure. Following S. molesta removal (or shade-effect elimination), there was a positive response to aquatic ecosystem species abundance, richness, diversity and community structure. Therefore, in combination, aquatic biota recolonisation rate and increases in biological and functional diversity were instrumental in the recovery of ecosystem structure and functions, following the control of S. molesta. Echoing existing literature, this thesis recommends: (1) IAAP species management programmes (mechanical and/or biological control) should not only aim to control the weed but also focus on ecosystems recovery and possible restoration goals; (2) biological control should be used where appropriate to combat free-floating IAAP species in freshwater ecosystems, followed by active introduction of native macrophyte propagules since they are limited by anthropogenic activities; and (3) more freshwater case studies are needed to add to our understanding of IAAP species management and restoration effort incorporating long-term monitoring.
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  • Date Issued: 2020

Reef fish associations with benthic habitats at a remote protected coral reef ecosystem in the Western Indian Ocean-Aldabra Atoll, Seychelles

  • Authors: Haupt, Philip
  • Date: 2020
  • Subjects: Coral reef ecology -- Aldabra Islands (Seychelles) , Reef fishes -- Aldabra Islands (Seychelles) , Benthic animals -- Aldabra Islands (Seychelles)
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/141629 , vital:37991
  • Description: The aim of the thesis is to develop an understanding of the associations between reef fish and benthic habitats and assess the modifying effects of environmental processes on these relationships at Aldabra, a pristine atoll in the Western Indian Ocean (WIO). Conducting research in pristine, or reference coral reef ecosystem, removes the impact of direct anthropogenic disturbances and provides essential information on natural ecosystem structure and functioning. Three primary hypotheses were tested: 1) Environmental drivers such as depth and exposure to wave energy determine the spatial distribution of benthic habitats; 2) The reef fish assemblage structure is explained by habitat at multiple scales and modified by the effects of environmental drivers such as depth, wave energy and cyclical temporal drivers such as time and tides; 3) The reef fish assemblage at Aldabra represents a pristine reef fish assemblage, comprising high levels of herbivores and predators. The research focussed on the benthic habitat on the seaward reefs between the shoreline and 50 m depth. The first objective was to characterise the benthic habitats on Aldabra Atoll’s seaward reefs and map their spatial distributions using remotely sensed imagery and ground truthing data. The second was to assess the influence of depth and exposure to wave energy on the distribution of benthic habitats. The third was to identify the most suitable standardised method to survey the reef fish assemblage structure on Aldabra’s, and fourth to determine the effect of tide and time of day on the reef fish assemblage. The fifth objective was to establish the association between reef fish assemblage structure and benthic habitats and to test how species-size influenced the scale of habitat at which the associations were most apparent. Four categories of geomorphic reef zones (reef flats (19.2 km2), top of the forereef slope (7.8 km2), deep forereef slope (11.6 km2), and reef platform (14.3 km2)) were manually delineated following the visual outlines of reef features from satellite imagery. The six broad-scale and twelve fine-scale benthic habitats were mapped using a supervised maximum likelihood classification and the spatial coverage of each determined. The broad-scale habitats were 1) Epilithic algal matrix, 2) Hard and soft (coral, 3) Rubble, 4) Macroalgae, 5) Seagrass and 6) Sand. Similarly, twelve fine-scale benthic habitats were characterised and mapped, for example, Hard coral (19 %) including massive and submassive forms with Millepora and Rhytisma. The broad-scale benthic habitat map had an overall producer accuracy of 54 % and fine-scale habitat map 29 %, which was consistent with studies using similar habitat classification methods. The prevailing wave energy, depth and the directional orientation of coral reefs (aspect) significantly influenced the probability of occurrence of each of the broad-scale benthic habitats, and there was a shift in peak probability of occurrence of all habitat categories to a greater depth with an increase in wave energy. The strong relationship of benthic habitats with depth and wave energy suggests that the distributions of benthic habitats are likely to change with sea-level rise and increased intensity and frequency of storms in future. Overall, 338 fish species from 51 families, including 14 species of elasmobranch were recorded using Baited Remote Underwater Video systems (BRUVs) and unbaited Remote Underwater Video systems (RUVS) from 231 samples. Fish were significantly more abundant when observed using BRUVs (119 ± 7) relative to RUVs (92 ± 7), and the assemblage structures were significantly different between the two sampling methods. Abundance and species richness of generalist carnivores and piscivores were significantly greater in BRUVs, while RUVs recorded significantly greater numbers of herbivores and more species of herbivore and corallivore. The results suggest that BRUVs are better suited when studying predatory fish which may not be detected without bait. However, when surveying a taxonomically and functionally diverse assemblage of fishes at a pristine reef, RUVs may provide a more accurate estimate of natural reef fish assemblage structure. Reef fish assemblages observed using RUVs were significantly different between morning-high-tide, midday-low-tide and evening-high-tide for all trophic groups. However, the reef fish assemblage structure observed using BRUVs was insensitive to change in tide and time of day, which may be explained by the attraction effect of bait dampening the effect of tide and time of day. While RUVs appear better to detect more subtle variations in fish assemblage structure, care needs to be taken when designing research programmes that use RUVs, as the sampling design should account for tide and time of day to avoid misinterpreting the cyclical variation, which may confound results. Reef fish assemblages were significantly different among habitats within geomorphic reef zones, broad-scale and fine-scale habitats. Species turnover rates were significantly different for all Actinopterygii size-class categories between the three scales of habitat. No marked differences in species turnover rates among habitats were detected for the majority of Elasmobranch size-class categories. The strong habitat dependency over various spatial scales indicates that effective conservation of Actinopterygii fish at Aldabra, and elsewhere in similar ecosystems requires protection of representative sets of benthic habitats. However, Elasmobranch conservation requires sufficiently large areas as these species utilise multiple habitats, over multiple scales, which are likely to exceed the confines of Aldabra’s reef.
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  • Date Issued: 2020

Resource recovery options in brewery effluent treatment using activated sludge and high rate algal ponds: assessing environmental impacts

  • Authors: Taylor, Richard Peter
  • Date: 2020
  • Subjects: Sewage -- Purification -- Activated sludge process , Sewage disposal plants , Sewage -- Purification -- Biological treatament , Sewage -- Purification -- Nitrogen removal , Brewery waste , Breweries -- Waste disposal , Microalgae -- Biotechnology , Algal biofuels
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/153746 , vital:39507
  • Description: Wastewater treatment plants (WWTPs) are designed to clean effluents, but they also consume resources and produce waste. Various treatment technologies allow for the recovery of energy, nutrients and water from effluents turning this waste into products, which increases their sustainability and decreases the impact of WWTPs on the environment. There is a lack of literature which comprehensively compares the treatment performances, environmental impacts and beneficial downstream uses of the biomass generated by high rate algal pond (HRAP) and activated sludge (AS) treatment systems. This thesis aimed to compare (1) effluent treatment performance, (2) emissions and (3) downstream use of algae cultured in HRAP to sludge produced in AS and to obtain data to conduct a life cycle analysis (LCA) to compare the systems. The focus was on adding value to the effluent treatment process, while identifying the associated environmental impacts and contributing to the first ever zero-waste brewery effluent treatment system. Furthermore, these data were used to provide a basis to critically review and contribute to improving the methods used in the LCA of effluent treatment systems; particularly since this was the first wastewater treatment LCA that compared AS and HRAP using data collected from the same temporal and geographic location and from a single effluent stream. The electrical consumption water emission and land application of waste biomass caused the major environmental impacts of both treatment systems. The HRAP had less than 50 % of the electrical energy consumption (0.11±0.01 kW/m3 of effluent treated) compared to the AS system (0.29±0.11 kW/m3) which resulted in the technology having a lower climate change, photochemical oxidant formation, freshwater and marine ecotoxicity and fossil fuel depletion impact. It is imperative to understand the method of electrical energy (fossil fuel vs renewable) generation when conducting a LCA and deciding which technologies to use, since they have a major influence on the aforementioned impacts. The biogas yield of algal and sludge substrates was similar with an average gas production of 241 ml/g volatile solids fed. Biogas from algae fed digesters had a significantly higher methane content (64.73±0.81 %) and lower carbon dioxide content (22.94±0.24 %) when compared to WAS fed digesters (60.08±0.18 % and 27.37±0.43 %) respectively due to it being a less oxidised substrate. Swiss chard plants (Beta vulgaris) fertilised with anaerobically digested (AD) algae or sludge had a significantly higher mean biweekly yield (5.08±0.73 kg/m2) when compared to the inorganic-fertiliser control (3.45±0.89 kg/m2; p<0.0001). No difference was observed in the soil’s physical fertility when algae or sludge were applied to the soil (p>0.05). The HRAP produced more biomass (317.18±27.76 g/m3) than the AS (83.12±64.91 g/m3), which resulted in a significantly greater downstream production of biogas and fertiliser per volume of effluent treated. According to the LCA, this also resulted in the HRAP system having a higher terrestrial ecotoxicity, due to the greater volume of solids and thus heavy metals applied to the soil. This interpretation can be misleading, because the mass of heavy metals released into the environment is the same for both systems, with a greater portion being applied to the land in the HRAP scenario and discharged into fresh water in the case of AS. Future LCA models should clarify if these biomasses are going to be applied to a single piece of land or multiple sites as this will influence the risk of contamination via pollutant build up in the soil. The application of sludge or algae on soil increased the soil’s sodium concentration and sodium absorption ratio from 774.80±13.66 mg/kg to 952.17±34.89 mg/kg and 2.91±0.04 to 3.53±0.13, respectively. Regulations on the application of algae or sludge on agricultural soils should be altered to consider the limit values for sodium and future LCA’s associated with effluent treatment facilities should incorporate the possibility of soil contamination through sodium build-up. This work also conceptualised the importance of reporting water emissions in wastewater treatment LCA in as much detail as possible, because this had a significant influence on the eutrophication impacts on water systems. Reporting water emissions as total nitrogen underestimated downstream eutrophication impacts compared with those using nitrogen-species concentration (ammonia, nitrite, nitrate etc). A marine eutrophication sensitivity co-efficient should be included in future LCA models which accounts for the probability of nitrogen and phosphorus emissions entering the coastal environment as well as the vulnerability of the marine environment to eutrophication. Activated sludge systems are favourable for situations where space is limited, were there are inadequate options for biomass disposal (biomass not be used in agriculture or AD) and were electricity is generated from a renewable source; whereas, HRAP are more suitable under circumstances where electricity production relies on fossil fuel that carries a high environmental impact and where options are available to use the biomass for economic gain such as biogas and fertiliser production. This thesis contributes towards a zero-waste brewery effluent treated process. The HRAP and AS treated effluent for reuse in the brewery or in agricultural irrigation. The solids were anaerobically digested, and the carbon was recovered as a biogas, while the digestate was applied as an agricultural fertiliser. This allowed for the recovery of water, nutrients and carbon.
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  • Date Issued: 2020

Rural enterprise development as a means to poverty alleviation

  • Authors: Bodley, David Cyril
  • Date: 2020
  • Subjects: Rural development -- South Africa , Economic development projects -- South Africa Poverty alleviation -- methods -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/50361 , vital:42118
  • Description: South Africa’s disappointing economic performance over the last decade has resulted in a socio-economic crisis, with unemployment and inequality rates being of the highest rates anywhere in the world. Furthermore, unemployment is concentrated among the young, unskilled, and previously disadvantaged population posing a considerable threat to South Africa’s new democracy. Internationally, a method to absorb job seekers into the economy is to make small business the engine-room of economic growth and development. Consequently, the South African Government has identified in its National Development Plan the establishment of small businesses as a priority, including the development of small businesses in rural and marginalised communities. As rural communities in South Africa experience systemic problems such as the lack of infrastructure, financial capital, skills and potential markets, establishing enterprises in rural settings is often more complex than those more advanced parts of the economy elsewhere where fewer constraints exist. This makes the task of establishing and growing rural entities particularly challenging, suggesting bespoke policy and support is required. This study analyses the literature to gain an understanding of economic development theory and how this intersects with and informs small enterprise development policy. It then looks at South Africa’s strategy and policy framework pertaining to enterprise development. Specifically, the literature examines the role of rural enterprise development to establish whether this enables people to move out of poverty or further entraps people in poverty. The study collates data from a rural and marginalised community through observation and interview techniques. Firstly, multiple in-depth interviews were conducted with nineteen entrepreneurs in a rural community to collect data on business opportunities and explore the type of support entrepreneurs would require from government. Secondly, a focus group interview was conducted with entrepreneurs that had experienced institutional support to understand how well current policy and programmes support rural enterprise development. The primary data was analysed in conjunction with the literature on economic theory and enterprise development using the technique of triangulation to avoid logic leaps and formation of false assumptions. The insights and findings from the analysis reinforced certain facts within the body of knowledge pertaining to enterprise development, but there were also some interesting new insights that emanate from the data. South Africa has been able to introduce a wide range of policy initiatives and has multiple programmes and strategies to support small enterprise development. It has achieved firm success and impetus as well as experiencing certain failures. The study clearly highlights both and makes recommendations to improve policy promoting rural enterprise development as a means to alleviate poverty.
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  • Date Issued: 2020

Socio-ecological, contextual effects in Raven’s Colour Progressive Matrices scores: Developing an index for guiding test selection and interpretation

  • Authors: August, Justin Oswin
  • Date: 2020
  • Subjects: Ecological Systems Theory
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/46401 , vital:39563
  • Description: With the changing landscape in South Africa to a full democracy, increased research has been undertaken in the psychometric field on local and national normative studies regarding various assessment measures. Given that the Raven’s Coloured Progressive Matrices (CPM)is purported to be culture-free and not heavily dependent on verbal and language skills;it has been extensively normed throughout the world for various population groups. While norms for normal populations of children have been developed in South Africa, these studies were based on race and gender predominantly and without taking into consideration the effects of socio-ecological factors on test performance. The research study aimed to understand the influence of socio-ecological factors on the expression of cognitive scores amongst a geographically diverse sample of South African learners. Through this study, research on the interplay between context and cognition was to be located within the Ecological Systems model of Bronfenbrenner. A secondary aim of the study was to develop an index that will guide test selection and interpretation of assessment results, taking into account the influence of socio-ecological factors and providing a conceptual framework for future test development. The study employed a quantitative methodology on a South African sample consisting of primary school children aged between the ages of 6 years to 11 years. The sample was drawn from schools in the Port Elizabeth areain South Africa that wereclassified into low, medium and high opportunity, based on context. The results indicated that the type of school had a significant impact on test performance, suggesting that contextual factors were influential in this process.The item analysisconductedfurther indicated that learners from a low opportunity school performed significantly lower than the other two schoolsin the sample. The index development provides a foundation for further research that would enhance the interpretation of test results. In the South African context, this is considered important, given our political history and our diversity wherea“one size fits all” approach is not possible.
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  • Date Issued: 2020

Strategies for the facilitation of implementation of best practice guidelines in operating theatres at public hospitals

  • Authors: Owolabi, Olukemi Olufunmilayo
  • Date: 2020
  • Subjects: Operating rooms—Safety measures
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/46422 , vital:39594
  • Description: Best practice guidelines (BPGs) are the use of scientific evidence to direct patient care and guide clinical care to integrate best patient outcomes. The implementation of BPGs in operating theatre nursing improves patient safety and quality of care and enhances patient outcomes. Although BPGs are crucial, the implementation thereof is not well operationalised in clinical practice, especially in an area such as the operating theatres in public hospitals in the Nelson Mandela Bay Health District(NMHD)in the Eastern Cape Province. The study thus developed strategies that could be used to facilitate the implementation of best practice guidelines in the operating theatres at public hospitals in the NMBHD. Understanding registered nurses’ knowledge, attitudes, and practices (KAP) with regard to implementing BPGs in the operating theatre is important, as it will assist in the development of strategies to facilitate the implementation of BPGs.The study was conducted in three phases. Phase One comprised of a quantitative approach. Data collection was achieved by means of a self-administered questionnaire which was distributed to registered nurses in the operating theatres of public hospitals in the NMBHD. The purpose of the questionnaire was to establish their knowledge, attitude and practice with regard to best practice guidelines and the implementation thereof. Recommendations made by participants for strategies to facilitate the implementation of BPGs in operating theatres were also explored. Descriptive and inferential statistics were utilised to analyse and describe the data. Descriptive statistics were used to describe the profile of the sample, including the demographic data measures of central tendency, for example the mean and standard deviation (SD) and correlation techniques.Chi²analysis was performed to test for significance of the associations between the registered nurses’ demographic variables and their KAP. Data were categorised into three levels, namely lower (score < quartile 1 i.e. bottom 25%). Middle (quartile1 ≤ score ≤quartile i.e. in the middle 50%) and higher (score > quartile 3 i.e. top 25%).Findings from this research study revealed the limited knowledge, attitude and practice of OT nurses about BPGs. During Phase Two an integrative literature review approach was followed in order to identify the best available evidence with regard to the facilitation of the implementation of best practice guidelines in operating theatres. Lastly, Phase Three: strategies that could be used to facilitate the implementation of best practice guidelines in operating theatres were developed. The researcher developed the conceptual framework using the six elements of Dickoff, James and Weidenbach (1968:422). The conceptual framework informed the development of strategies. The strategies are a synthesis of the conclusions drawn from the research findings (phase one and two) and the conceptualization thereof. The strategies were reviewed by six-panel members. Each panel member was supplied with the format for evaluation of the strategies which was based on the criteria established by Chinn and Kramer (2018:156) the results of which included in chapter 7. The researcher ensured that the data obtained was valid and reliable, necessary to assist the researcher to produce quality research. Ethical considerations were maintained throughout. In general, the results of this thesis indicate that the developed strategies that could be used to facilitate the implementation of best practice guidelines, in operating theatres at public hospitals in the NMBHDare unique and could be implemented in theatres in public hospitals. The researcher succeeded in achieving the purpose for this study, because the strategies which are understandable, clear, simple, applicable and significant to operating theatre unit has been developed for use by operating theatre nurses, to facilitate the implementation of best practice guidelines in operating theatres at public hospitals in the NMBHD.
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  • Date Issued: 2020

Synthesis of novel heterocyclic systems as potential inhibitors of HIV-1 enzymes

  • Authors: Sekgota, Khethobole Cassius
  • Date: 2020
  • Subjects: Protease inhibitors , Heterocyclic compounds , HIV (Viruses) , Quinoline , Amides , Nuclear magnetic resonance , Antiretroviral agents , AIDS vaccines , Nitrobenzaldehyde , Propylphosphonic acid anhydride
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/146502 , vital:38531
  • Description: This study has focussed on the application of Baylis-Hillman methodology in the development of efficient synthetic pathways to libraries of novel 3-[(N-cycloalkylbenzamido)methyl]-2-quinolones and indolizine-2-carboxamides and on an exploration of their medicinal potential. The approach to 3-[(N-cycloalkylbenzamido)methyl]-2(1H)-quinolones involved a six-step pathway comprising: Baylis-Hillman reaction of 2-nitrobenzaldehyde derivatives and methyl acrylate to afford nitro-Baylis-Hillman adducts; thermal cyclisation of the adducts to give a range of 3-(acetoxymethyl)-2(1H)-quinolones in good to excellent yields; hydrolysis of the acetates; conversion of the resulting alcohols to the 3-chloromethyl analogues; amination; and, finally, acylation to afford the target amides. Variable temperature NMR methods were used to facilitate analysis of the ¹H and ¹³C NMR spectra which were complicated by internal rotation and cycloalkyl ring-flipping effects. On the other hand, the indolizine-2-carboxamides were obtained in several steps commencing with the Baylis-Hillman reaction of pyridine-2-carboxaldehyde and methyl acrylate. Thermal cyclisation of the Baylis-Hillman adduct afforded indolizine esters, hydrolysis of which gave the corresponding acids which served as precursors to the target indolizine-2-carboxamides. The final amidation step, however, proved to be particularly challenging. Various coupling strategies were explored to access indolizine-2-carboxamides. These included the use of 2,2,2-trifluoroethyl borate which showed limited promise, but propylphosphonic acid anhydride (T3P) proved to be the most effective coupling agent, permitting the formation of 24 novel indolizine-2-carboxamides from hydrazines, aliphatic amines and a range of heterocyclic amines. A high-field NMR-based kinetic study of the mechanism of the Baylis-Hillman reaction of pyridine-4-carboxaldehyde and methyl acrylate in the presence of 3-hydroxyquinuclidine in deuterated chloroform was initiated, reaction progress being followed by the automated collection of ¹H and DEPT 135 NMR spectra over ca. 24 hours using a high-field (600 MHz) NMR instrument. The results have provided critical new insights into the mechanism. NMR analysis has also been used to elucidate the multiplicity of signals associated with rotameric equilibria observed at ambient probe temperature. Variable temperature 1D- and 2D-NMR spectra were used to facilitate the unambiguous characterisation of the 2-quinolone benzamides and some of the indolizine-2-carboxamides. The 3-[(N-cycloalkylbenzamido)methyl]-2(1H)-quinolones, together with selected precursors, and a number of the indolizine-2-carboxamides have been screened in vitro as potential HIV-1 enzyme inhibitors. A survey of the activity of the 2-quinolones against HIV-1 integrase, protease and reverse transcriptase revealed selective inhibition of HIV-1 integrase with the most active IN inhibitor, 3-[(cyclopentylamino)methyl-6-methoxy-2(1H)-quinolone 115e, producing residual enzyme activity of 40% at a concentration of 20 μM. Many of the 2-quinolones exhibited no significant cytotoxicity against HEK 293 cells at 20 μM concentrations. 3-[(N-Cyclohexylamino)methyl]-6-methoxy-2(1H)-quinolone 114e was the only compound to exhibit ant-plasmodial activity (55% pfLDH activity). The survey of indolizine-2-carboxamides also revealed encouraging inhibition against HIV-1 integrase. None of these compounds exhibited cytotoxicity at 20 μM against HEK 293 cells, while a number of them exhibited some activity against Plasmodium falciparum (3D7 strain) and Trypanosoma brucei. Selected indolizine-2-carboxamides exhibited significant anti-tubercular activity in the 7H9 CAS GLU Tx and 7H9 ADC GLU Tw media. In view of the inherent fluorescent character and biological potential of the synthesised indolizine-2-carboxamides, their photophysical properties were explored to establish their possible dual use as bio-imaging and therapeutic agents. The major absorption and corresponding emission bands, and the associated molar absorption coefficients (Ɛ) expressed in the form of log Ɛ were determined. Their high extinction coefficients, large Stokes shift and red-shifted emissions in the visible region indicate their potential for use as fluorophores.
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  • Date Issued: 2020

Synthesis, characterisation and antitumour activities of lanthanide complexes with hydrazones and carboxylic acid ligands

  • Authors: Madanhire, Tatenda
  • Date: 2020
  • Subjects: Organic acids
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/48456 , vital:40878
  • Description: The tridentate hydrazone ligands, (E)-N'-(2-hydroxybenzylidene)benzohydrazide (H2phen) and (E)-N'-(2-hydroxybenzylidene)nicotinohydrazide (H2Nic), were synthesised and complexed to Ln(III) acetates. The centrosymmetric, acetato-bridged dinuclear coordination compounds with the formulae, [La2(Hphen)2(OAc)4(H2O)2]·DMF·H2O (1), [Ln2(HNic)2(OAc)4(H2O)2]·DMF·H2O (Ln = La (2) and Nd (3)) and [Ln2(HNic)2(OAc)4(H2O)2]·DMF (Ln = Er (4) and Yb (5)) were isolated and characterised by elemental analyses, IR spectroscopy, UV-Vis spectroscopy, X-ray diffraction studies and SHAPE 2.1. The nine-coordinate complexes 1–3 crystallise in the triclinic space group P-1, with the metal centres having the distorted spherical capped square antiprism geometry (C4v), while the eight-coordinate Er(III) and Yb(III) complexes (monoclinic system, space group P21/c) display the geometry of distorted triangular dodecahedron (D2d). Geometry optimisation of the monoanionic forms of the hydrazone ligands (Hphen– and HNic– ) were performed using Density Functional Theory (DFT) with Becke’s three parameter hybrid method and correlation functional of Lee, Yang and Parr (B3LYP) with augcc-pVTZ basis set. Natural population analysis (NPA) and molecular electrostatic potential (MEP) maps indicated that the most preferred sites for electrophilic attack in the anionic ligands are the phenolate and carbonyl oxygens, and the azomethine nitrogens. The evaluation of the cytotoxic activity of the compounds on breast cancer (MCF-7), the endometrial carcinoma (HEC-1A) and the human monocytic (THP-1) cell lines using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide (MTT) assay revealed that the hydrazone ligands and complexes 1–4 are partially cytotoxic against MCF-7 cells, while the Schiff bases and complexes 3–5 significantly inhibit cell growth in HEC-1A cells. The complexation reactions of Ce(III), Nd(III), Gd(III) and Er(III) with the chelating/ bridging monoanionic ligand N-(2,6-dimethylphenyl)oxamate (Hpma– ) in basic media were performed in view of the potential applications of oxamate derivatives as cytotoxic agents. The coordination compounds were characterised by different Abstract T. Madanhire Nelson Mandela University xxvi physico-chemical techniques: elemental analysis, conductivity measurements, IR, 1 H NMR and UV-Vis-NIR spectroscopy. The anionic Hpma– was obtained through conversion of the proligand ethyl (2,6-dimethylphenylcarbamoyl)formate (Hdmp). The reactions afforded lanthanide(III)–oxamate coordination polymers of formulae: {[Ln(Hpma)3(MeOH)(H2O)]∙2MeOH}n (Ln = Ce (1) and Nd (2)), {[Gd2(Hpma)6(MeOH)4]∙6MeOH}n (3), {[Er2(Hpma)6(MeOH)(H2O)3]∙2MeOH}n (4) and [Ln2Na2(Hpma)8(EtOH)(H2O)6]n (Ln = Nd (5) and Gd (6)). The polymeric complexes feature Ln-Hpma moieties bridged by μ2-η 1 :η 1 :η 1 Hpma– , giving onedimensional zig-zag chains of the –Ln–O–C–O–Ln– type. Atomic charge analysis and the MEP map of the Hpma– moiety done using the DFT/B3LYP method were found to be consistent with the chelating and bridging modes of the anionic ligand through all the oxygen atoms. The evaluation of the cytotoxic activities of the metal salts, the proligand and the novel lanthanide complexes on MCF-7, HEC-1A and THP-1 cell lines revealed that only the rare-earth metal salts [Ce(NO3)3∙6H2O] and [Nd(NO3)3∙6H2O] showed modest cytotoxicity against MCF-7 and HEC-1A cells, respectively.
  • Full Text:
  • Date Issued: 2020

Synthesis, characterisation and electrocatalytic behaviour of three series of Metal Organic Frameworks

  • Authors: Murinzi, Tafadzwa Wendy
  • Date: 2020
  • Subjects: Electrochemistry , Metal-organic frameworks , Polyoxometalates , Fourier transform infrared spectroscopy , Electrocatalysis , Cysteine
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/167598 , vital:41495
  • Description: Metal organic frameworks (MOFs) have received a lot of attention over the past few years due to their vast range of interesting properties and applications, such as catalysis, environmental sensing and storage. This wide range of potential applications is afforded by careful selection and manipulation of the components chosen in assembling of MOFs. In this study, three series of MOFs were synthesized from Co(II), Cu(II) and Mo(VI) polyoxometallates with either 1,3,5-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid or 2,6- pyridinedicarboxylic acid as the ligands. In series 1, the common 1,3,5- benzenetricarboxylic acid MOF, HKUST-1, and POM modified HKUST-1 compounds involving encapsulation and encorporation of the POM were utilised. In series 2, flexible cobalt(II) benzenepolycarboxylate MOFs which investigated the effect of varying the degree of carboxylate substituent were utilised. In series 3, flexibly reduced heterocyclic polycarboxylate MOFs using 2,6-pyridine dicarboxylate were utilised. Solvothermal and slow evaporation synthesis conditions were employed. Where single crystals of good quality were produced, single crystal X-ray diffraction (SC-XRD) was employed for structural elucidation. In the absence of such crystals, a combination of elemental analysis, inductively coupled plasma optical emission spectrometry (ICP-OES) and powder X-ray diffraction (PXRD) was used. Characterization of the MOFs was done by Fourier transform infrared spectrometry (FTIR) and thermal methods, namely thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The electrocatalytic potential of the compounds in the oxidation of L-cysteine was then investigated using a variety of techniques. Cyclic voltammetry was used for L-cysteine detection whilst chronoamperometry and differential pulse voltammetry were used to determine the nanoprobes’ sensitivity, rate constants and detection limits. Electrochemical impedence spectroscopy was used to investigate the charge transfer resistance (RCT) and electron transfer kinetics. Of the three, series 3 gave the best signals and sensitivities for electrocatalysis of L-cysteine followed by series 2 and lastly series 1. Series 2 showed the highest stability and series 1 required the least overpotential. The results highlight the effects of different metal centres and ligands on electrocatalysis. The application of MOFs in electrochemistry is a relatively new field making the findings of this study a significant addition to the body of knowledge.
  • Full Text:
  • Date Issued: 2020

Synthesis, crystal structures and molecular modelling of rare earth complexes with bis(2-pyridylmethyl)amine and its derivatives : a quantum chemical investigation of ligand conformational space, complex intramolecular rearrangement and stability

  • Authors: Matthews, Cameron
  • Date: 2020
  • Subjects: Rare earths , Complex compounds , Ligands
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/46229 , vital:39517
  • Description: Limited research has been performed on the coordination behaviour of hybrid aliphatic and heterocyclic polyamines with trivalent rare earth elements. The rare earth coordination properties of several Nalkylated derivatives of the tridentate ligand bis(2-pyridylmethyl)amine (DPA, HL1) backbone - involving the rare earth elements Y, La-Nd, Sm, Eu and Tb-Lu - have been investigated in this study However, the structural and energetic characteristics of DPA coordination with rare earth elements (REE) have not been studied thus far. Potential applications of DPA-based rare earth complexes are primarily dependent on their electronic and magnetic characteristics, which are affected weakly by the coordination environment, where potential applications may include use as Lanthanide Shift Reagents (LSR), Luminescence probes and small-molecule magnets (SMM). A systematic conformational search of DPA was carried out in this study in order to identify the global minimum conformer and for comparison of the free and coordinated geometries, using the M06(D3) functional belonging to the Density Functional Theory (DFT) family of model chemistries. An understanding of the aforementioned would play an important role in analysis of bulk characterization and the prediction of the reactivity of DPA. Final geometries and electronic energies were obtained from the ‘domain based local pair natural orbital’ (DLPNO)-Møller-Plesset and -coupled cluster theoretical methods, as follows: DLPNO-CCSD(T0)/aug-cc-pVQZ//DLPNO-MP2/aug-cc-pVTZ. Fifteen Single-crystal X-ray diffractometer (SC-XRD) crystal structures of mononuclear rare earth chloride coordination complexes with DPA (RE = La-Nd, Sm, Eu, Tb-Lu and Y) were obtained and geometrically analysed in this study. Three isostructural series of constitutional isomers were identified, consisting of one series of nine-coordinate molecule (M1) and two series of eight-coordinate ion pairs (M2 and M3). This conformational diversity is most likely due the flexible nature of the DPA backbone, as well as the additional stability gained from reduced coordination spheres as a function of decreasing rare earth ionic radii across the lanthanide series (Lanthanide contraction). A Quantum Theory of Atoms-in-Molecules (QTAIM) topological analysis was performed in order to identify and characterise potential hydrogen bonding interactions in H-optimised crystal structures. The crystal structures of five dinuclear (RE = Tb-Tm) and two tetranuclear (RE = Yb and Lu) rare earth chloride complexes with DPA have also been structurally analysed. Furthermore, one mononuclear (RE = Dy), two dinuclear complexes (RE = Dy and Lu) with EtDPA, and one mononuclear complex with the DPA-derivative HL4 (RE = Dy) were structurally characterised. A DFT study of the theoretical interconversion of one real- and two hypothetical- mononuclear lanthanum containing isostructural series (cf. aforementioned crystal structures) was undertaken in order to gain a deeper understanding of the processes involved, in terms of the participating minimum energy paths (MEPs), intermediates and transition states – as determined via the Nudged-Elastic Band (NEB) procedure. This hypothesis is supported by the well-known conformational lability of rare earth complexes, due to the weak/minor covalency of their coordination bonds. An attempt was made to determine the respective energies of one real- and two hypothetical diamagnetic or ‘closed-shell’ constitutional isomers containing the rare earth ions La3+(M1), Y3+(M2) and Lu3+ (M3). It was assumed that the most stable isomers have a greater probability of being observed as the asymmetric unit of the complex crystal structure – assuming weak contributions of lattice or intermolecular interactions towards the geometry of the asymmetric unit.
  • Full Text:
  • Date Issued: 2020

Teachers’ perceptions, experiences and challenges related to using ICTs in teaching Social Sciences in marginalised classrooms in the Eastern Cape Province, South Africa

  • Authors: Gunzo, Fortunate Takawira
  • Date: 2020
  • Subjects: Educational technology -- South Africa -- Eastern Cape , Teachers -- In-service training -- South Africa -- Eastern Cape , Social sciences -- Study and teaching -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Technological innovations -- Employee participation -- South Africa -- Eastern Cape , Teachers -- Attitudes , Technological innovations -- Economic aspects -- South Africa -- Eastern Cape , Technology Acceptance Model , Teacher Cognitions theory
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/146964 , vital:38581
  • Description: This study seeks to examine teachers’ perceptions and experiences of using Information and Communication Technology (ICT) in teaching as the basis for actual use in the classroom. I conducted an eclectic study with a multidisciplinary theoretical viewpoint combining theories from Information Technology (IT) and education to examine how perceptions and prior experiences with ICT influence cross-curriculum ICT integration. Specific aspects of five theories and models were used in different phases of this study. I drew on the Technology Acceptance Model (TAM) and Teacher Cognitions theory to understand teachers’ perceptions towards ICT in general and towards ICT in the classroom. The classroom observations were conducted using an observation guide informed by Activity theory. I then utilised the Adoption of Innovation and the Diffusion of Innovation theories to explain why and how ICT was utilised in the classrooms. A mixed methods research approach located within a pragmatic paradigm was chosen. Three data sets were collected. First, a questionnaire of attitudes and perceptions towards ICT was conducted with 183 teachers (mainly working at marginalised schools in the Eastern Cape Province of South Africa). Questionnaire data was analysed using descriptive statistics and a chi-square correlations test. Second, teachers enrolled in an in-service Advanced Certificate in Education specializing in ICT (ACE-ICT) at Rhodes University were supported in planning and implementing an intervention involving the use of a mobile computer lab in rural and peri-urban schools. Three key participants were observed while teaching in class using ICT for the first time and they were subsequently interviewed. Third, drawing from lessons learnt from this experience, students in the in-service education bachelor’s degree in ICT (BEd-ICT) – which replaced the in-service ACE-ICT – were supported and encouraged to experiment with cross-curriculum integration using ICT already at their disposal. Planning and reflections by three in-service BEd-ICT teachers were subjected to theory-based document thematic analysis. Findings indicate that the vast majority of the teachers had positive attitudes towards ICT and perceived ICT as useful, mainly as a productivity tool in teaching. ICT was used mostly for administration, planning and preparation of lessons and not for teaching or as a cognitive tool. Despite all key participants having access to similar ICTs and support, their experiences of teaching with ICT were different based on their personal commitment, access to and frequency of use of ICTs in their personal lives. Teachers who were self-motivated to use ICT in their teaching made efforts to do so regardless of infrastructure and resource challenges they faced at their schools. The main barriers to the use of ICT in the classroom appear to be lack of technical support and time constraints.
  • Full Text:
  • Date Issued: 2020

Temporal patterns and seasonal variation in microplastic loads in the water column and in the tissues of consumers along the southern and south-eastern coasts of South Africa

The characterization and application of novel xanthenyland thioxanthenyl-derived compounds as hosts in the presence of various applicable guest mixtures

  • Authors: Jooste, Daniel Victor
  • Date: 2020
  • Subjects: Organic compounds -- Synthesis
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/49104 , vital:41601
  • Description: In this work, the host potential of four novel, structurally-related compounds, trans- N,N’-bis(9-phenyl-9-xanthenyl)cyclohexane-1,2-diamine (1,2-DAX), trans-N,N’-bis(9- phenyl-9-thioxanthenyl)cyclohexane-1,2-diamine (1,2-DAT), trans-N,N’-bis(9-phenyl- 9-xanthenyl)cyclohexane-1,4-diamine (1,4-DAX), and trans-N,N’-bis(9-phenyl-9- thioxanthenyl)cyclohexane-1,4-diamine (1,4-DAT), were investigated for their possible employment in the separation of isomers and other related compounds using host– guest chemistry. These hosts were synthesized following a Grignard reaction with phenylmagnesium bromide on either xanthone or thioxanthone. The resultant alcohol was treated with perchloric acid, before finally being linked with either trans-1,2- or trans-1,4-diaminocyclohexane to afford the four title host compounds. Initially, the feasibility of these hosts for separating isomers and related compounds was investigated by recrystallizing each one independently from various guest compounds including the methylpyridines and pyridine, xylenes and ethylbenzene, heterocyclic six-membered ring compounds, aniline, N-methylaniline and N,Ndimethylaniline, and also the alkylbenzenes toluene, cumene and ethylbenzene. 1HNMR spectroscopy was used to ascertain if inclusion of the guest species had occurred in this manner and, if so, the host:guest ratio of the complex. Guest–guest competitions were subsequently conducted in order to establish the selectivity of the hosts when presented with a mixture of guests, and if the host would be able to discriminate between them. Gas chromatography-mass spectrometry (GC-MS) was the analytical method of choice here if 1H-NMR spectroscopy was not suitable owing to guest–guest signal overlap. Here, the host was recrystallized from binary, ternary and quaternary mixed guests, where each was present in equimolar amounts. Additionally, binary competition experiments were conducted in mixed guest solvents where the molar ratios of the guests were varied, and host selectivity for these guests evaluated visually by means of selectivity profiles. Single crystal X-ray diffraction (SC-XRD) and thermal analysis were performed on any complexes that afforded crystals of suitable quality in order to relate inherent host–guest interactions and thermal stability to the observed host selectivity from the competition experiments. The more prevalent interactions that were evident in these inclusion complexes between host and guest species were, more usually, and interactions, as well as other short contacts. Hydrogen bonding interactions were observed in only a few of the complexes. Guest accommodation type was also investigated, and these species resided in either discrete cavities or channels within the host crystal, depending on the guest. For the most part, traces obtained from thermal analyses were highly convoluted and difficult to interpret. As a result, guest release onset temperatures could not be determined for all of the inclusion complexes. In some cases, however, this temperature was successfully measured and correlated directly with the observed selectivity order of the host suggested by the competition experiments. Both enhanced and contrasting results were obtained for the four host compounds. In all cases, 1,2-DAX and 1,2-DAT successfully formed complexes with each of the guest species from each series. Interestingly, the 1,4-derived hosts, however, were more selective in that 1,4-DAX did not complex with only one of the guest solvents, while 1,4-DAT did not enclathrate as many as ten of these solvents. The competition investigations showed that, in most of these experiments, the host compounds displayed selectivity for one of the guests present in the mixture, and in some cases, this selectivity was pronounced, alluding to the feasibility of separating related guests from one another through host–guest chemistry principles. Computational calculations were, additionally, conducted on each of the host molecules in order to gain a better understanding of their geometries, and to compare these with the apohost crystal structures. Significant geometry differences were noted between the calculated and crystal structures.
  • Full Text:
  • Date Issued: 2020

The current role of palm species Hyphaene Coriacea and Phoenix Reclanata in local livelihoods in the Zitundo area, southern Mozambique

  • Authors: Martins, Angelina R O
  • Date: 2020
  • Subjects: Ilala palm -- Economic aspects -- Mozambique , Palms -- Economic aspects -- Mozambique , Non-timber forest products industry -- Mozambique , Sustainable development -- Mozambique , Conservation of natural resources -- Mozambique
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/150613 , vital:38989
  • Description: The majority of rural households in developing countries are heavily dependent on non-timber forest products (NTFPs) to fulfill much of their basic daily needs. In Mozambique more than 64% of the population lives in rural areas and depends heavily in the extraction of NTFPs to complement agricultural production. One substantial source of NTFPs are palm species. Palms are sources of food, building materials, cloth, ornaments, medicines, and are also used for cultural purposes. In southern Mozambique two important palms species used as NTFPs are Hyphaene coriacea and Phoenix reclinata. These two species provide an array of subsistence and commercial products. The sap, leaves and stems of these two palms are harvested by local people as sources of traditional beverages, weaving, roofing, fencing and furniture material as well as other household utensils. The effects (if any) of harvesting of these palm products on palm distribution, population structure, dynamics and viability have never been examined, and thus the sustainability of the practices and benefits flows to local livelihoods are unknow-n. Any effects harvesting effects may also be exacerbated by predicted climate change for the area. The present study aims to investigate the role of the palm species Hyphaene coriacea and Phoenix reclinata in the livelihoods of households in the Zitundo area, Matutuine district, southern Mozambique and under future climate scenarios. Specifically, this study: i) evaluates the abundance, population structure and harvesting selection of these species; ii) characterizes the ethnobotanical knowledge and use of the two species; iii) examines the local production and trade of palm wine in the area; iv) examines the contribution of palm income to livelihoods and income diversification in area; v) describes the local management practices and perceptions on palm productivity and abundance; and vi) models the current and future distribution of the these palm species in the area. To evaluate the abundance, population structure and stability of these two palm species a population census was carried out, and the size class distribution, Simpson index of dominance, permutation index and the quotient between successive size classes were calculated. I further calculated the preference ratio for specific size classes. Additionally a questionnaire survey was conducted with 179 randomly selected households from the 16 villages in the study area to characterize the ethnobotanical knowledge and use of these two species, as well as to examine the contribution of palm income to livelihoods and diversification. Standard ethnobotanical indices were used as measures of each palm species use and knowledge while principal component analysis and cluster analysis were applied to highlight the livelihood patterns and the role of diversification and of palm income in local livelihoods. Structured interviews with 37 palm tappers were additionally used to examine the local production and trade of palm wine in the area, while both the household survey and palm tappers interviews, were employed to investigate the local management practices and perceptions on palms productivity and abundance. Maxent Software was used to model the current and future under climate change distribution of the two palm species. Hyphaene coriacea was more abundant than Phoenix reclinata. Both species exhibited steep negative slopes in the regression analyses of size class distribution, indicating the presence of more individuals in shorter size classes. Although there was a dominance of shorter over taller size classes, limited recruitment was observed through low stem densities of seedlings and juveniles compared to the 1-50 cm size class The Simpson index of dominance, the permutation index, and the fluctuating quotients between the consecutive size classes showed a level of instability in both populations. Hyphaene coriacea appeared to be more resilient to tapping than Phoenix reclinata as showed by the higher rate of stem survival after tapping. Hyphaene coriacea was favored for tapping compared to Phoenix reclinata. The most preferred size class to tap for both species was between 101cm and 150 cm. Currently the distribution of Hyphaene coriacea and Phoenix reclinata was mostly confined to the eastern side of the study area. Most of the area was predicted as unsuitable for both palm species, with less than six percent predicted to be suitable or higher. The occurrence of both species appeared to be influenced mostly by water related variables, such as precipitation, and distance to rivers and distance to water bodies. The habitat suitability for Hyphaene coriacea was predicted to increase under future climate conditions scenarios, while little variation was predicted for Phoenix reclinata distribution. The knowledge about the uses of these two palm species was widespread in the area, although only 32% of respondents were engaged in palm exploitation. Thirteen palm products were exploited, with palm wine production from the sap of both palms being the dominant activity, followed by broom production from Phoenix reclinata stems and basket production from Hyphaene coriacea leaves. The cultural importance of these species included the production of anklets and skirts used during traditional dances and the use of palm wine in the traditional ritual of libation. Palm tapping was practiced year round in five of the sixteen villages in the area. Palm tapping was an important livelihood activity, contributing over 80% of tappers’ total annual income, and tappers earned up to three times more than the national minimum wage for the agricultural and forestry sector. Palm wine was also a highly commercial commodity in Zitundo area, with an average commercialization index above 60%. The income from palm wine sales showed an important role in mitigating the level of poverty in the area. Palm income accounted for over 60% reduction on poverty incidence among palm tappers. Households in Zitundo further engaged in some level of livelihood diversification. The majority of households adopted a wage-based strategy, although this strategy was among the less remunerative in terms of per capita cash income. A palm-based livelihood strategy, although adopted only by 11% of households, was one of the most remunerative strategies. Palm income played a vital role in enhancing household livelihoods and mitigating poverty in the area as shown by the lower poverty incidences among households engaged in the palm-based livelihood strategy than alternatives strategies. The village of household residency, along with household demographic and socio-economic characteristics appeared to determine the knowledge and exploitation level of palms as well as a households’ choice of livelihood strategy, level of palm wine returns, commercialization index and palm income dependency. The importance of palms in local livelihoods and poverty alleviation needs greater acknowledgement by government and development agencies in the area. Palm wine, broom and basket production have a high potential for income generation, and therefore should be included in future local development policies and poverty reduction strategies. Although palms are an open access resource in Zitundo area, the perception is that they are abundant and that tapping does not have many detrimental effects. However, this study found some negative impacts of tapping on the recruitment of both palms species. The inclusion of palm products in future development programs and poverty reduction strategies will require the design of participatory conservation and management strategies that involve all palm users groups and others stakeholders and include long-term participatory monitoring of the effect of palm use on the populations.
  • Full Text:
  • Date Issued: 2020

The determination of whether a Unified Communication System can be effective in supporting informal communication and collaboration in virtual teams

  • Authors: Hill, Kyle
  • Date: 2020
  • Subjects: Telecommuting , Virtual work teams , Telecommunication systems , Computer networks
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/146343 , vital:38517
  • Description: The overall objective of the research is to determine whether a Unified Communication System intervention can be effective in supporting informal communication and collaboration in virtual teams. In so doing, this research is aimed at developing a current framework of critical success factors for facilitating informal collaboration and communication. As teams have evolved to the point where there is no longer a need for team members to be co-located, with a greater importance now being placed on how they collaborate, this framework will also highlight how it can support virtual teams due to the huge potential advantage they can provide to the organisation. A virtual communication and collaboration system will be selected based on the outputs of the current framework and interactions which occur through the system will be observed to provide quantitative and qualitative results. In conclusion, the research will suggest recommendations for the successful implementation of informal communication and collaboration technologies within the organisation. The research will also indicate to a limited degree, the impact of the implementation of these technologies, and the outcome for the organisation, whether positive or negative. Whilst conducting the research, it became apparent that while the UCS was capable of performing the processes and functions required, the individuals and teams engaging with the technology did not always make use of the full scope of the technology provided. Regardless, a UCS was observed to provide direct benefits to an organisation in increasing communication and collaboration in the organisation. These increases can be observed in both the physical and virtual sense. However, the converse is true for generating social capital which lead to the observation that there are a smaller number of interactions happening in the smaller teams, but these are of higher value when compared to the larger teams of this study. It is also clear that the larger a team becomes, the more the trend is to focus on adopting new technologies to make their roles more efficient. This adoption is not however translated into outputs such as social capital but is translated into stronger networks and the formation of new networks. It is also clear that most negative factors around the UCS are related to the respondent’s hardware rather than the solution itself. Cost reductions because of virtuality will also be observed and using the Developed Framework as a blue print, an organisation should be able to observe direct benefits for an organisation by being able to confirm the thesis of this research in that having a UCS intervention is effective in supporting informal communication and collaboration in virtual teams.
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  • Date Issued: 2020

The development of a set of guidelines for the revision of psychological tests and the use of revised psychological tests

  • Authors: Cronje, Johan Herman
  • Date: 2020
  • Subjects: Psychological tests
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/46350 , vital:39567
  • Description: The psychological testindustry has produced a wide variety of psychological tests that are used by professionals to facilitate measurement and decision-making. Tests are updated and revised periodically in order to remain current, valid and reliable in what is a competitive psychometric industry. Despite the prevalence of test revisions, especially in recent years, a number of authors have commented on the lack of comprehensive guidelines for test revision. Guidelines shouldcover aspects such as what the different types of revision are, when to embark on a revision, whatprocessto followand how test users should use revised tests. Test revision differs from test construction in a number of ways. There are external factors that affect the regularity with which a test should be revised. Test revision also involves more role players than test construction, including the opinions of those test users who may be resistant to any change in the previous test edition. Finally, revised tests sometimes have to contend with requirements from the test publisher who purchased the test or distribution rights from the developer. Test revision is expensive and time consuming, which leaves little scope for experimentation or trial-and-error. The availability of expertise, as well as the human and financial resources required to complete test revisionscan make such projects unaffordable, especiallyforprofessionals indeveloping countries, such as South Africa.It may be more feasible for such professionalsto collaborate with international revision projects. By doing so they cangain experience in test revision, contribute indigenous information that could shapethe revision ofan international test, increase opportunities to engage with international users, and potentially source international funding for research in their own country. The current studydevelopeda comprehensive and practical set of 30 guidelines to assist those involved in test revision. These guidelines were peer-reviewed and refined. Finally, the guidelines were field-tested using a case study of a recently revised ivdevelopmentaltest, the Griffiths III. Professionals from South Africa, including the present researcher,formed part of the international team for the extensive revision of the Griffiths III, which makes this test an ideal case study from both the perspectives of the developed test revision guidelines as well as collaboration of professionals from a developing country in an international test revision. The knowledge gainedfrom the development of guidelines and international collaboration in test revision is reflected on.
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  • Date Issued: 2020

The effect of gamma radiation on the physical and chemical properties of wool

  • Authors: Rapakgadi, Jim
  • Date: 2020
  • Subjects: Semiconductors -- Effect of radiation on
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/47668 , vital:40263
  • Description: Pathogens (e.g. viruses, spores and bacteria) remain one of the biggest threats to trading and the economy of natural fibre products, such as wool, mohair and cotton. One of the means to kill or eliminate pathogens is by radiation sterilisation, involving electromagnetic radiation (e.g. gamma radiation and UV light). The research, reported in this thesis, was aimed at establishing the effect of gamma irradiation dosage on the various quality related physical and chemical characteristics of four different types of merino wool when treated in situ in scoured and greasy state in mini-bale form. Specific properties studied include wool colour (yellowness and brightness), solubility (alkali solubility and urea bisulphite solubility), fibre diameter and tensile properties (staple strength and bundle tenacity). Standard analytical and diagnostic techniques were used to assess changes, if any, in the above mentioned properties due to the radiation treatment. Nominal radiation dosages, ranging from 25 kGy to 75 kGy (actual measured from 0 kGy to 92.2 kGy) were used, 50 kGy normally being regarded as sufficient to destroy the pathogens in question. It was found that nominial gamma radiation dosages of up to 92.2 kGy did not significantly affect fibre diameter or staple length, indicating that no irreversible swelling of the wool fibres occurred as a result of gamma irradiation. Alkali and urea bisulphite solubility as well as yellowness, on the other hand, showed a systematic increase with an increase in irradiation dose, indicating that changes occurred at molecular level. Fibre tensile properties (staple strength and bundle tenacity) were also affected but to a much lesser extent than solubility and colour. The various merino wool types studied showed similar reactions to the radiation treatment, irrespective of the wool quality and type and also whether they were treated in greasy or scoured form.
  • Full Text:
  • Date Issued: 2020

The effects of economic and political instability on decentralised secondary schools in Mashonaland Central Province, Zimbabwe: a case study

  • Authors: Katsinde, Tapfuiwa James
  • Date: 2020
  • Subjects: Education, Secondary -- Political aspects -- Zimbabwe , Political violence -- Zimbabwe , Zimbabwe -- Economic conitions -- 1980- , Zimbabwe -- Politics and government -- 1980-
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/165610 , vital:41263
  • Description: The purpose of the study was to analyse the effects of economic and political instability on decentralised secondary schools in Mashonaland Central Province, Zimbabwe between 2000 and 2017. Previous studies in Zimbabwe and elsewhere have shown that schools were negatively affected by economic and political instability. This study adds to this literature by using habitus as a conceptual framework. This was a qualitative study which made use of a multi-case research design. Data was collected using focus group discussions, interviews and document analysis. Eight research sites in the form of secondary schools in four districts were used. Data analysis was done using theoretical prepositions guided by research objectives and research questions. Data presentations was characterised by quotes of participants. Trustworthiness based on dependability, credibility, transferability and conformability formed the basis of quality assurance measures. The study revealed that economic and political instability had similar negative results in the field of secondary schools in the province. Economic instability negatively affected school activities which included teaching and learning, administration and development work. In addition economic instability affected individual secondary school actors psychologically. Economic instability affected relations among the secondary school actors by aggravating already existing contestations amongst actors. Similarly, political instability affected secondary school activities such as teaching and learning, school administration, development, donations and social benefits. Secondary school actors were individually affected psychologically and through physical abuse and the way they responded to political instability. The study has shown that decentralised secondary schools found it difficult to solve the problems introduced by economic and political instability especially when the instabilities occurred within the difficulties of the broader Zimbabwean context. It is therefore recommended that decentralised secondary schools should be assisted financially and with resources to withstand economic challenges. There is a need to protect secondary schools from political activities and activists as these have devastating effects on education if allowed to have a free reign. Further similar research is recommended for other provinces in the country.
  • Full Text:
  • Date Issued: 2020

The Effects of exchange rates on bilateral trade balances of SACU members states with their trading partners

  • Authors: Mhaka, Simbarashe
  • Date: 2020
  • Subjects: Economic development -- South Africa , Purchasing power parity -- Econometric models
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/50371 , vital:42152
  • Description: The fluctuations of exchange rates prevent countries from achieving stability in their external account records. Appreciation or depreciation has effects on international trade. This thesis examines the relationship between exchange rate fluctuations on bilateral trade balances focusing on the SACU region. There are several theories made to explain the relationship between exchange rate and trade balances. In examining this phenomenon, this thesis will unveil if the purchasing power parity theory, the Marshall-Lerner condition and the J-curve effect holds in the Southern African Customs Union (SACU) countries. This analysis is divided into three parts. The first part examines the stability of the exchange rate in the SACU countries in the long run as given by the purchasing power parity. To test for the Purchasing Power Parity theory, the recently developed powerful unit root test was applied with multiple smooth structural breaks of Omay (2015), based on a Fractional Frequency Flexible Fourier Form (FFFFF) on unique data of SACU countries covering the monthly period of 1995M01-2017M11. The Purchasing Power Parity (PPP) results show that the nominal effective exchange rate (NEER) of all SACU members does not provide evidence for PPP theory. In terms of the real effective exchange rate (REER), the PPP condition holds in the case of South Africa only. Further unit root investigations were carried out using the panel data for all SACU members, NEER and REER. The FFFFF test results for panel data shows strong evidence of the PPP while the standard DF test rejects PPP theory in the SACU’s NEER. Both the standard DF and the FFFFF tests show strong evidence of PPP theory in the case of SACU’s REER. The second section of the analysis examines the Marshall-Lerner condition employing annual data from the period of 1980-2017. The import and export model were examined firstly in a time series format and then in a panel data format. The time series data was examined using the ARDL (PMG) model while the panel data used the panel ARDL, fully modified OLS (FMOLS) method and the Dynamic OLS (DOLS) method of estimation. The PMG/ARDL model shows no evidence to support the existence of the Marshall-Lerner condition in the short run for all SACU members. However, only two out of five countries show evidence of the Marshall-Lerner condition in the long run. There is strong evidence of the Marshall-Lerner condition in Namibia and Botswana in the long run using the PMG/ARDL model.
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  • Date Issued: 2020
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