The development of high-throughput assays to screen for potential anticancer and antimalarial compounds that target ADP-ribosylation factor 6 and its signalling machineries
- Authors: Khan, Farrah Dilshaad
- Date: 2019
- Subjects: ADP-ribosylation , Proteins -- Metabolism , Nucleoproteins , Malaria -- Chemotherapy , Cancer -- Chemotherapy
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92952 , vital:30810
- Description: ADP-ribosylation factors (Arfs) are small GTP-binding proteins that cycle between active GTP-bound forms and inactive GDP-bound forms. GDP/GTP cycling is regulated by large families of guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs). ArfGEFs activate Arfs by mediating the exchange of GDP for GTP, while ArfGAPs terminate Arf function by stimulating the hydrolysis of the terminal phosphate group of GTP. Arf6 is a major regulator of endocytic trafficking and reorganization of the actin cytoskeleton in eukaryotic organisms. Owing to its participation in wide range of fundamentally distinct cellular processes, Arf6 may be a drug target for cancer and malaria amongst other diseases. As with cancer cells, rapid growth and viability of eukaryotic pathogens likely places a heavy burden on their endocytic pathways and a critical reliance on Arf6 activity. A putative malarial homolog of Arf6 (PfArf6) localises to numerous puncta along the periphery of the parasite in the mature trophozoite life stage of the parasite (T. Swart, MSc dissertation). Owing to highly inefficient parasite transfection procedures and a relative shortage of well described and validated parasite organelle markers, the possible functions of PfArf6 were explored using HeLa cells as a surrogate model for parasites by fluorescence microscopy of cells transfected with GFP-tagged PfArf6. Partial co-localisation was observed with the mammalian markers HsArf6 and LC3, which suggested possible roles in Arf6-dependent endocytosis and autophagy, respectively. While these possible roles are currently under investigation in parasites, an overall long-term goal which was initiated in this study was to determine whether PfArf6 is a valid drug target. To chemically validate PfArf6 as a drug target, a potent inhibitor needs to be identified. This requires the development of assays that may be employed for high-throughput screening of compound libraries. To support this goal, a novel plate-based assay was developed using human Arf6. The assay relies on the selective binding of an Arf effector protein domain (GGA3) fused to glutathione-S-transferase (GST), to His-tagged Arf6 immobilised on a nickel-coated plate. The assay format was developed and could robustly distinguish HsArf6-GDP (inactive) from HsArf6-GTP (active). Furthermore, it could be employed to detect the deactivation of Arf6 by ArfGAP1-stimualted GTP hydrolysis, but not Arf6 activation by ARNO-stimulated GDP/GTP exchange (ARNO is an ArfGEF). The ArfGAP1 deactivation assay was chemically validated using a known ArfGAP inhibitor, QS11. An improved assay was developed that employs JIP4 as an Arf6-specific binding partner instead of GGA3. In addition to superior performance, the alternative assay format could potentially be exploited for cancer drug discovery, since Arf6-JIP4 interaction has been implicated in cancer cell invasion and metastasis. Both assays may be employed to explore alternative ArfGEFs and ArfGAPs that act on Arf6 and contribute to the advancement of cancer. In parallel experiments, where development of PfArf6 assays was the focus, several issues arose. Firstly, we could not prepare GDP- and GTP-bound forms of PfArf6 since EDTA-mediated nucleotide exchange appeared to irreversibly destabilise the protein. However, PfArf6 activation (i.e. the preparation of PfArf6-GTP) was possible when mediated by ARNO and assessed by tryptophan fluorescence kinetic assays, suggesting that PfArf6 may be expressed in GDP-bound form in E. coli. As with human Arf6, ARNO-mediated GDP/GTP exchange on PfArf6 was not detectable in the immobilised PfArf6-GGA interaction GST assay format. However, a more sensitive assay was developed which relies on the use of nickel-horseradish peroxidase to detect the binding of His-tagged PfArf6 to JIP4-GST immobilised on glutathione plates and could detect ARNO-mediated PfArf6 activation. Since we could not prepare PfArf6-GTP (that did not rely on the presence of the ArfGEF, ARNO), malarial ArfGAP deactivation studies were conducted using PfArf1 instead of PfArf6 in the GGA-GST interaction assay. Both PfArfGAP1and PfArfGAP2 stimulated GTP hydrolysis by PfArf1, but only the former was inhibited by the standard human ArfGAP inhibitor, QS11. The development of these simple, cost-effective assays can be used in the high-throughput screening of novel anticancer and antimalarial compounds that target Arf signalling machineries. In theory, the assay could be extended as a tool to identify novel inhibitors of the multitude of Arfs, ArfGEFs and ArfGAPs originating from any organism and hence has broad clinical significance.
- Full Text:
- Date Issued: 2019
The diffusion of Max condoms among young women in KwaZulu Natal
- Authors: Donald, Charlene Chenaye
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/96870 , vital:31342
- Description: HIV is a disease that has a myriad of effects across different settings, and its prevalence varies across countries with different epidemiological drivers. The growing and disproportionate impact on young women has encouraged new ideas in HIV prevention strategies. The profusion of studies on HIV prevention strategies notwithstanding, the aspect of condom innovation has been largely ignored in literature. Drawing on the Diffusion of Innovation theory, this study examines how Max condoms have gained popularity among young women aged 18-24 years. The hypotheses are tested using an innovation-decision conceptual model and a comprehensive data set of 131 participants from rural, peri-urban and urban districts in KwaZulu Natal. Results reveal that the impact of marketing material and an effective public launch were significant in increasing Max condoms uptake, while the influence of peers and other members of one’s social system are critical for normalising the behaviour change. Young women have adopted Max condoms and uptake is continually influenced by positive perception of Max condoms’ relative advantage.
- Full Text:
- Date Issued: 2019
The dispersion measure in broadband data from radio pulsars
- Authors: Rammala, Isabella
- Date: 2019
- Subjects: Pulsars , Radio astrophysics , Astrophsyics , Broadband communication systems
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67857 , vital:29157
- Description: Modern day radio telescopes make use of wideband receivers to take advantage of the broadband nature of the radio pulsar emission. We ask how does the use of such broadband pulsar data affect the measured pulsar dispersion measure (DM). Previous works have shown that, although the exact pulsar radio emission processes are not well understood, observations reveal evidence of possible frequency dependence on the emission altitudes in the pulsar magnetosphere, a phenomenon known as the radius-to-frequency mapping (RFM). This frequency dependence due to RFM can be embedded in the dispersive delay of the pulse profiles, normally interpreted as an interstellar effect (DM). Thus we interpret this intrinsic effect as an additional component δDM to the interstellar DM, and investigate how it can be statistically attributed to intrinsic profile evolution, as well as profile scattering. We make use of Monte-Carlo simulations of beam models to simulate realistic pulsar beams of various geometry, from which we generate intrinsic profiles at various frequency bands. The results show that the excess DM due to intrinsic profile evolution is more pronounced at high frequencies, whereas scattering dominates the excess DM at low frequency. The implications of these results are presented with relation to broadband pulsar timing.
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- Date Issued: 2019
The effect of age and culture on brand loyalty in the South African motor industry
- Authors: Hempel, Martin Johan
- Date: 2019
- Subjects: Brand loyalty -- South Africa , Automobile industry and trade -- South Africa , Consumer satisfaction -- South Africa , Consumer behavior -- South Africa , Older consumers -- South Africa , Consumers -- South Africa -- Cross-cultural studies
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/96859 , vital:31339
- Description: It has become imperative for companies in the motor industry to study and understand the notion of brand loyalty due to the many inherent advantages that it offers. Although existing literature provides extensive information on brand loyalty, the concept of brand loyalty is not constant across all industries. Factors such as age and culture also alter the effects of brand loyalty and the degree of brand loyalty generated within a consumer. Taking these variables into account, this study sets out to establish if age and culture have an effect on brand loyalty in the South African motor industry. The method in which motor companies emit marketing signals are also explored to establish if the emitted marketing signals are able to assist in the generation of brand loyalty. A South African real estate agent group agreed to participate in the research and became the sample population for the study. 190 successfully completed questionnaires were obtained in the data collection process and data with a Cronbach Alpha Coefficient (α) of 0.7662 proved that the data had satisfactory reliability. The data was processed and analysed in the statistical analysis program Stata. The study discovered that marketing signals don't assist in the generation of brand loyalty in the South African motor industry. It is suggested that it is more plausible that marketing signals can assist to maintain brand loyalty, rather than to generate brand loyalty. The study also discovered that culture does not have an effect on brand loyalty in the South African motor industry. However, after considering that the cultural distribution of the sample was significantly skewed, the sample is regarded as an unreliable test of the effect of culture on brand loyalty. The study also discovered that age doesn't have an effect brand loyalty in the South African motor industry. The researcher noted that the previously cognitively strenuous process of obtaining information has become more simplified by the internet and could potentially have reduced the generating of brand loyalty among older consumers. A final test was conducted to ascertain if relationships exist between the four stages of loyalty. The study suggested that all four loyalty stages are connected which confirms that brand loyalty is generated by both attitudinal and behavioural dimensions.
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- Date Issued: 2019
The effect of bait on fine-scale habitat associations of reef fish investigated with remote underwater video systems
- Authors: Schmidt, Nicholas C
- Date: 2019
- Subjects: Baited remote underwater stereo-video systems (stereo-BRUVs) , Remote underwater stereo-video systems , Underwater videography in wildlife monitoring -- South Africa -- Tsitsikamma , Fish stock assessment -- South Africa -- Tsitsikamma , Fish populations -- Monitoring -- South Africa -- Tsitsikamma , Fishes -- Habitat -- South Africa -- Tsitsikamma
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/68380 , vital:29249
- Description: Establishing the associations between fish and their habitats can aid in the monitoring of fish stocks and the design of effective marine protected areas (MPAs). Baited remote underwater stereo-video systems (stereo-BRUVs) are now commonly used to asses fish populations. The habitats seen in the video footage of stereo-BRUVs can be used to link fish fauna to preferred habitat types. However, the application of bait potentially attracts fish from surrounding habitats, and might result in a biased understanding of fish–habitat associations. A field study was conducted in the Tsitsikamma National Park MPA to determine the effect of bait on fine-scale fish–habitat associations, using remote photographic and video methods. The study was conducted over the summer season of 2015 and 2016. Data were collected within a 1x1 km shallow (9–44 m) reef complex. Within the sampling area, 944 photo-quadrats of the macrobenthos were taken 30 m apart by means of a drop camera. By separating the macrobenthos into broad taxonomic groups, five habitat types were identified, namely Shallow Sand, Shallow Reef, Deep Reef, Deep Sand and Patch Reef. The results show that even on a fine scale, depth is an important predictor of macrobenthic distribution and assemblage structure. Baited (stereo-BRUVs) and unbaited (stereo-RUVs) surveys were then conducted to sample the fish community in the same area during the period under study. Higher abundances of fish were observed in reef than in sandy habitats, and bait was seen to have a positive effect on species richness and fish abundance. When comparing habitats, fish abundance and composition on reef habitats were significantly different from sand habitats. This was observed in both the stereo-RUVs and stereo-BRUVs methods. High counts of roman (Chrysoblephus laticeps), fransmadam (Boopsoidea inornata) and steentjie (Spondyliosoma emarginatum) in reef habitats were contrasted by high counts of white sea catfish (Galeichthys feliceps), evil-eye puffer (Amblyrhynchotes honckenii) and lesser guitarfish (Rhinecanthus annulatus) in sandy habitats. Overall, the underlying patterns in fish diversity recorded with the two video methods were generally comparable. However, stereo-RUVs appeared to be unable to detect species that were present in sand habitats, while stereo-BRUVs increased the number and abundance of species recorded in all habitat types. In the stereo-RUVs footage, differences between reef habitats were dampened by the presence of highly abundant fish species. In the stereo-BRUVs footage, although bait appeared to have an effect on the observed fish assemblage, this manifested in an increase in species richness, higher fish abundances and a better overall ability to detect fish–habitat relationships. As such, stereo-BRUVs are considered a robust, effective and recommended method for detecting fish–habitat relationships, even over a fine scale.
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- Date Issued: 2019
The effectiveness of sandplay therapy with a Xhosa child
- Authors: Snelgar, Orrin Glenn
- Date: 2019
- Subjects: Sandplay -- Therapeutic use -- Case studies -- South Africa , Play therapy -- Case studies -- South Africa , Child psychotherapy -- Case studies -- South Africa , Children, Black -- Psychology -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/179168 , vital:39876
- Description: This case study sought to determine whether Kalffian Sandtray Therapy was effective with a Xhosa child. In the context of ongoing discussions surrounding evidence-based practice and culturally appropriate interventions, no published research has yet explored the effectiveness of this classical tool within this significant South African demographic. In an effort to address this omission, the research adopted a mixed methods approach where Kalffian analysis of the sandplay process was evaluated in conjunction with quantitative measures (the Strengths and Difficulties Questionnaire and the Young Person’s Clinical Outcomes in Routine Evaluation). The results of this triangulation revealed a complex picture of improved interpersonal functioning and stagnant (or worsened) emotional wellbeing after five sessions. Contextualised interpretations of these findings are discussed and recommendations made for future sandplay practice and research in the South African context.
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- Date Issued: 2019
The experiences of health service providers working with children with physical disabilities and their caregivers in the Eastern Cape
- Authors: Mathaba, Yollandah
- Date: 2019
- Subjects: Children with disabilities -- South Africa -- Eastern Cape , Caregivers -- South Africa -- Eastern Cape -- Case studies , Caregivers -- Psychology , Children with disabilities -- Care
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/76299 , vital:30545
- Description: The prevalence of childhood disability in South Africa is significant. In an attempt to meet the constitutional rights of children with disabilities, there are a variety of services available for children with disabilities. These services are aimed at rehabilitating children with disabilities and integrating them in society. Amongst such services are health services. Due to the nature of some childhood disabilities, it is recommended that they should be seen by a multidisciplinary team. While the field of childhood disability has been researched extensively. Limited research has been conducted on the experiences of health service providers working with children with disabilities and their caregivers. The current study explored the experiences of health service providers working with children with disabilities and their caregivers in the Eastern Cape. To achieve this aim, the study employed Interpretative Phenomenological Analysis (IPA). Five participants were recruited using purposive and snowball sampling methods. Semi-structured interviews were used to allow participants to freely share their experiences of working with children with disabilities and their caregivers. The interviews were audio recorded and transcribed for analysis purpose. The analysis process generated five master themes namely: Positive experiences of their work; negative experiences of their work; perception of their role as changing over time; managing challenges in their work; and experiences of a service learning programme as complementary to their work. The findings of the study highlighted both the positive experiences and the negative experiences of their work. On the one hand, the participants reported positive affect and that they found their work meaningful. They also reported a sense of feeling supported by fellow colleagues and enjoying their work at the clinics. On the other hand, the participants reported negative affect in relation to their wok difficulties such as feelings of frustration, feelings of being unappreciated by management and finding the work distressing. The participants reported that professional and emotional growth in conjunction with perspective taking contributed to developing better coping mechanisms. A service learning programme offered in the community was experienced as a good contribution to the work done at the clinics and distinguished as addressing the emotional needs of the caregivers which cannot be addressed at the clinics. The findings of the study supports and expands the literature on the experiences of health service providers working with children with disabilities in South Africa.
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- Date Issued: 2019
The extent of urban Green Collar employment, its contribution to poverty alleviation and potential for growth in the Eastern Cape, South Africa
- Authors: King, Andrew
- Date: 2019
- Subjects: Economic development -- Environmental aspects -- South Africa -- Eastern Cape , Poverty prevention -- South Africa -- Eastern Cape , Job creation -- South Africa -- Eastern Cape , Urban ecology (Sociology) -- South Africa -- Eastern Cape , Urban poor -- Employment -- South Africa -- Eastern Cape , Clean energy industries -- Employment -- South Africa -- Eastern Cape , Renewable energy sources -- Government policy -- South Africa -- Eastern Cape , Land use, Urban -- South Africa -- Eastern Cape , Open spaces -- Environmental aspects -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/115191 , vital:34095
- Description: The aim of this research was to investigate the job provisioning benefits of urban green space (GS), the ability of these jobs to alleviate poverty amongst poor urban households, as well as the potential to increase the number of Green Collar (GC) jobs. According to Lal et al. (2010), Roy et al. (2012) and others, environmental employment or GC jobs, represent the very synergy between social, economic and environmental resilience and sustainability, and have the ability to provide an additional range of goods and services. Data was collected from 12 towns and cities in the Eastern Cape of South Africa, all varying in population, town size and geographic location. Structured employer, employee and resident interviews were used to collect data, which pertained to a number of employment characteristics and employee living conditions. Throughout the sample, 19 different types of jobs were identified, and a total of 17 429 GC employees were counted, sharing a total of approximately R503 million in annual wages. Some GC employees were found to still be in a position of poverty despite employment, while others enjoyed a higher standard of living as a result, although this was largely dependent on the extent of wages and other household and employment attributes. Using lessons learnt from previous chapters, a number of data sources and a creative approach, the potential for growth and improvement in the urban GC sector was discussed, and the way forward involves private, public, informal and civil sector participation and innovation; which will not only enhance environmental and social ecosystem services, but also provide meaningful employment opportunities to the otherwise impoverished. Urban GC jobs should be widely viewed as a useful tool in achieving social, environmental and economic prosperity in urban landscapes (Bowen and Kuralbayeva, 2015).
- Full Text:
- Date Issued: 2019
The impact of elephants on thicket vegetation and other mammals in the Eastern Cape Province, South Africa
- Authors: Nuttall-Smith, Gareth David
- Date: 2019
- Subjects: Albany Thicket -- Effect of browsing on , Elephants -- South Africa -- Eastern Cape , African elephant populations -- South Africa -- Eastern Cape , Woody plants -- Effect of browsing on -- South Africa -- Eastern Cape , Animal-plant relationships -- South Africa -- Eastern Cape , Vegetation monitoring -- South Africa -- Eastern Cape , African elephant populations -- Environmental aspects -- South Africa -- Eastern Cape , Biotic communities -- South Africa -- Eastern Cape , African elephant -- Food , Vegetation dynamics -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/76365 , vital:30554
- Description: African elephants (Loxodonta africana) were absent from large portions of the Eastern Cape Province of South Africa for more than 100 years following widespread hunting for ivory. However, recent shifts in land use practices have resulted in the establishment of many private game reserves throughout the region. Some of these reserves have reintroduced elephants, raising management concerns because of the perceived impact that elephants can have on vegetation and the animals that rely on it for resources. My thesis aimed to assess the role of elephants in determining the structure and complexity of the locally important Thicket Biome and how medium and large mammals are affected. I quantified the woody and succulent components of Albany Thicket across nine reserves with elephants between May 2016 and November 2017 using a modified Point-Centre-Quarter method. Camera traps were deployed at each site for the duration of a calendar year to measure the relative abundances of all medium and large mammals at the sites. Across all study sites, climatic conditions (specifically rainfall and temperature) were the primary drivers of woody vegetation structure and diversity. Elephants appeared to have little influence since they were reintroduced at low densities 20 years ago. The associated mammal communities were mostly influenced by the height and basal area coverage of the thicket across the sites. I conclude that because elephant populations have been maintained at relatively low densities across my study sites, negative effects on the thicket vegetation and the associated mammal communities were not observed. In fact, the establishment of private game reserves, even with elephants, present may offer sustainable conservation for the threatened Albany Thicket. However, these elephant populations are still relatively new and changes to the vegetation are likely to be cumulative. Thus, future research should focus on how the vegetation is affected over time. To this end, I recommend the establishment of permanent sampling stations across all reserves with elephants in the Eastern Cape Province.
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- Date Issued: 2019
The impact of unanticipated news announcements by the US Federal Reserve On South African stock returns
- Authors: Sibanda, Lorna
- Date: 2019
- Subjects: Monetary policy -- United States , International finance , South Africa -- Foreign economic relations -- United States , United States -- Foreign economic relations -- South Africa , Banks of issue -- United States , Investments -- South Africa , Stocks -- Prices -- South Africa , Stocks -- Rate of return , Rate of return -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/94703 , vital:31070
- Description: This thesis analyses whether monetary policy announcement shocks are transmitted across countries, with special emphasis on the impact of US Federal Reserve announcements on the South African stock market. Monetary policy is an important source of economic news and affects the risk perceptions of market participants. This study will improve the understanding of stock price determinants and possibly influence SA monetary policy in guarding against possible shocks originating from abroad. Using Federal Reserve Open Market Committee (FOMC) announcements over the period 2008 – 2014, the research studied changes in volatility of the South African FTSE/JSE All Share Index returns over this period. An event study and GARCH model approach was adopted to reach the goals of the analysis. The findings were a statistically insignificant connection between SA stock returns and both anticipated and unanticipated US Federal Reserve announcements. Over the sample period, each shock to SA stock returns persisted for approximately 4-5 months. Although SA stock return volatility demonstrated clustering behaviour (indicating sensitivity to economic shocks), the research could not find an obvious relationship between these spikes in volatility and US Federal Reserve announcements. It is concluded that South African stock returns do not change in response to unexpected US monetary policy announcements.
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- Date Issued: 2019
The implementation of a developmental-contextual framework for young adults’ career explorations
- Authors: Roberson, Natalie Georgia
- Date: 2019
- Subjects: Vocational guidance -- South Africa , Focus groups , Action research , Youth -- South Africa -- Social conditions -- 1994- , Self-Directed Search Questionnaire , Occupational aptitude tests -- Evaluation
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/114895 , vital:34053
- Description: Career development theory and counselling practices in South Africa, which have traditionally utilised imported theory, have long been and continue to be criticised as being unsuitable in contexts different to those in which they were developed. In light of this, the aim of this study is to customise and trial the Vondracek, Lerner, and Schulenberg (1986) Developmental-Contextual Framework of career development with a group of employment-seeking young adults at a local community-based setting, as the basis of a career development intervention. Research questions asked were ‘In what ways is the examination and discussion of developmental-contextual factors of the individual facilitative of career exploration, in addition to seeking to identify contextual factors that influence career thinking and associated decision making. In doing so, this study aims to contribute to the existing literature on the career development of South Africans. Focus group methodology, within an overarching framework of collaborative action research, was employed. The approach to career exploration here was that of peer learning through group discussion of developmental-contextual factors of the individual. Data were generated through pre-intervention questionnaires, collaborative action research cycles, participatory observation, focus group discussions, and post-interventionist semi-structured individual interviews. Template Analysis was used for the thematic organisation and analysis of the data. Findings were that the intervention facilitated increased self-knowledge in relation to career development, increased knowledge of work and careers, and enhanced career planning abilities. Findings further highlighted the limitations of imported career development theories and the importance of the utilisation and development of local career assessment instruments. The group setting was found to be of value in facilitating self-reflection, a source of motivation and a valuable source of career-related information.
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- Date Issued: 2019
The influence of artificial light on the foraging efficiency and diet of insect eating bats
- Authors: Bailey, Lauren
- Date: 2019
- Subjects: Predation (Biology) , Bats -- Effect of light on , Bats -- Nutrition , Moths
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/76376 , vital:30555
- Description: Artificial light may be altering the interactions between bats and moth prey. Unable to make use of bat evasion strategies around artificial light, eared moths are susceptible to exploitation by syntonic bats (using echolocation frequencies between 20-50 kHz within the hearing range of eared moths). Using a handheld plasma metabolite analyzer, I evaluated the foraging success of syntonic bats and rarer allotonic bats (using echolocation frequencies outside the hearing range of eared moths), in areas with artificial light and in areas of natural darkness. I used microscope diet analysis to determine whether bats were consuming more or fewer moths in areas with artificial light and in areas of natural darkness. Syntonic bats were more selective for moth prey under lit conditions, likely owing to a reduction in the ability of tympanate moths to evade bats. Moths increased in the diets of generalist syntonic bats (Pipistrellus hesperidus) foraging around artificial light sources. Some P. hesperidus individuals showed high β-hydroxybutyrate levels around lights, but there was no difference in β-hydroxybutyrate levels between lit and unlit conditions. There is insufficient evidence to reject the null hypothesis that the foraging success of syntonic bats is equivalent in lit vs unlit conditions. The foraging success and diets of allotonic bats, Rhinolophus capensis, appear to be negligibly impacted by artificial light on a small scale. My study emphasizes the need for a mechanistic understanding of the influence of artificial light on the foraging success of bat species. Bat-moth interactions may be influenced by other factors apart from the common assumption that increased refuelling rates will occur in syntonic species foraging on moths around artificial light.
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- Date Issued: 2019
The influence of leadership styles on employee commitment in the retail industry
- Authors: Mqomboti, Sakhile
- Date: 2019
- Subjects: Retail trade -- Management -- South Africa , Retail trade -- Employees -- South Africa , Employee loyalty -- South Africa , Leadership -- Case studies -- South Africa
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/93811 , vital:30947
- Description: Purpose – Companies operating in the South African retail industry have been experiencing a high staff turnover, reported to be standing at 36% (Kelly, 2016). The Edcon Retail Group and Taste Holdings have already indicated their strategic focus on staff turnover reduction in order to achieve their business objectives (Crotty, 2017; Laing, 2017). This research study explained the relationship between the three leadership styles of the Full Range Leadership Theory (FRLT) model developed by Bass and Avolio and three types of commitments from the three component model of Meyer and Allen. The research study was interested in the leadership style that contributes the most to commitment. The effective leadership style may be developed to improve the level of employee commitment in the South African Retail industry. Methodology – The research study used the total population of 300 subordinate employees from four stores of a retail company in the Rustenburg region in the North-West Province of South Africa. The Multifactor Leadership Questionnaire (MLQ 5X) instrument was adopted for leadership questionnaire data collection, the three-component model of commitment was adopted for data collection of the commitment questionnaire. Pearson Correlations quantitative data analysis was adopted to explain the relationship of the independent and dependent variables. Multiple Regression quantitative data analysis was adopted to test the strength of the leadership styles on commitment. Findings – The statistical analysis results of Pearson Correlations found weak but significant positive relationship between Transactional leadership style and both Normative and Continuance commitment. A weak but significant positive relationship was found between Transformational leadership style and Normative commitment. A weak but significant positive relationship was found between Passive/Avoidant leadership and continuance commitment. Transformational leadership style showed more strength in contribution to commitment, followed by the Transactional leadership style. Significant – This research study will expand the existing but limited leadership style and commitment body of knowledge in the South African retail industry. The South African retail companies will be able to develop the preferred leadership style by its employees and develop this leadership style in their managers to improve the commitment of their employees.
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- Date Issued: 2019
The integration of effluent treatment using constructed wetlands, with crop production and aquaculture
- Authors: de Jong, Martyn
- Date: 2019
- Subjects: Recycling (Waste, etc.) , Brewery waste , Sewage -- Purification , Beets , Mozambique tilapia
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/95767 , vital:31197
- Description: Breweries are major consumers of water and produce nutrient rich wastewater. Therefore, it is important to research technologies that optimise the reuse and recycling of this waste. This study compared different constructed wetlands (CWs) in terms of their potential for cleaning brewery effluent and simultaneously producing crops Beta vulgaris and fish Oreochromis mossambicus. Filling and draining times (FDT; 15 min, 30 min and 60 min) in tidal CWs were compared in Experiment 1. The 15 min FDT (6.52 ± 0.09 mg/l) and 30 min FDT (5.74 ± 0.09 mg/l) had higher dissolved oxygen (DO) than the 60 min FDT (5.40 ± 0.09 mg/l; p<0.05). This resulted in the 15 and 30 min FDT treatments reaching ammonia effluent discharge standards sooner than the 60 min FDT. Total plant harvest increased with increasing FDT; therefore, 15 min FDT was used as the FDT in tidal treatments in the following experiments. The aerated CW (5.81 ± 0.07 mg/l) and tidal CW (5.67 ± 0.07 mg/l) treatments had higher DO concentrations than the unaerated CW treatment (3.76 ± 0.07 mg/l; p<0.05) in Experiment 2. This resulted in lower ammonia concentrations on day 5 in the aerated and tidal CWs compared with the unaerated treatment (p<0.05). The tidal CW (23.97 ± 2.57 kg) had a total harvest that was approximately four times higher than the unaerated CW (p<0.05), which had the highest frequency of chlorosis and plant mortality; and was unable to treat ammonia to discharge standards. In Experiment 3, the aerated and tidal CW were compared with municipal-water as water sources for aquaculture. There were no differences in fish growth (p > 0.05). However, there were differences in water quality; with the municipal treatment having the lowest pH, EC and nitrate concentration (p<0.05); but all water quality parameters remained in a range suitably for fish production. Due to the tidal CW having the highest plant harvest and lowest frequency of chlorosis and mortality; it was the most suitable CW technology to clean the brewery effluent, and to produce B. vulgaris and water that could be used downstream in aquaculture.
- Full Text:
- Date Issued: 2019
The Intsomi Ambassadors: using communicative ecologies to enhance home literacy practices amongst working class parents in Grahamstown
- Authors: Gush, Cathy
- Date: 2019
- Subjects: Communication in economic development -- South Africa -- Makhanda , Literacy -- South Africa -- Makhanda , Literacy programs -- South Africa -- Makhanda , Education -- Parent participation -- South Africa -- Makhanda , Intsomi Project
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/71459 , vital:29855
- Description: Utilising theories of Communication for Development, the research explores how literacy practices in the homes of a group of working class, English second language parents in Grahamstown are affected by the introduction of new literacy material and insights Furthermore, it discusses how, and through which forms of media, these observed dynamics and changes in practice are best communicated to similar households. The issue of children's literacy development in South Africa is of serious concern, in particular the role that parents play and the level of support they give through home literacy practices. The context is one in which South African children have performed very poorly with regard to literacy levels in international benchmark testing as well as in national assessments. The summary report on the Progress in International Reading Literacy Study (PIRLS) found that some of the factors contributing to these poor results were the lack of reading resources in homes, as well as the lack of strong home-school partnerships in which parents took up the role of co-educators, or even of primary educators at the preschool stage. A group of parents employed by Rhodes University at the Grade 1 - 5 levels signed up to be the recipients of a programme supporting the literacy development of their primary and pre-primary school children. The Intsomi Project is run by the Rhodes Community Engagement Office as part of the Vice-Chancellor’s Education Initiative and provides close to 100 families with weekly reading material and educational games for their children, as well as workshops on the use of these materials and how they might benefit the children. Following a Participatory Action Research approach, a “vanguard” group of parent participants, known as the Intsomi Ambassadors, developed their role as literacy activists, becoming co-creators of media messages that utilised and built on the first stage of their communication within the group. The research explored how the principles and techniques of development support communication, and those of communicative ecologies, could be applied to explore, enhance and disseminate those qualitative changes in behaviour within households that positively affect children’s literacy development. In the process, it aimed to explore whether media representations that reflect the stories of parents trying out new literacy practices can create authentic, endogenous messages that resonate with people in similar circumstances, and can stimulate debate around the issue.
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- Date Issued: 2019
The invasion ecology of Nymphaea mexicana Zucc. (Mexican Water lily) in South Africa
- Authors: Naidu, Prinavin
- Date: 2019
- Subjects: Nymphaea Mexicana zuccarini , Nymphaea , Nymphaea -- Biological control -- South Africa , Water lilies , Nymphaea -- Ecology -- South Africa , Water lilies -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa , Aquatic weeds -- Biological control -- South Africa , Water lilies -- Ecology -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92920 , vital:30763
- Description: The Mexican water lily, Nymphaea mexicana Zuccarini, is an aquatic perennial, native to southern USA and Mexico, and has been introduced to South Africa via the ornamental plant trade. This species has rapid growth rates and becomes weedy in dams, ponds and rivers. It is currently listed as a NEM:BA category 1b invasive plant in South Africa. One possible management measure for this weed is biological control, but it is a novel target because no biological control programme has been initiated against it anywhere in the world. This study is intended as a baseline for the biological control programme against this plant in South Africa. Assessing the population structure and mode of reproduction of invasive alien plants is an imperative aid to determining if biological control is a suitable management option. Using amplified fragment length polymorphism (AFLP) molecular markers, I compared the amount of genetic variability and differentiation of N. mexicana in its native range (USA), and invasive range (South Africa). Results indicated a large genetic distance between populations in the USA and South Africa, compared to populations within each country. The genetic variability of the invasive populations was higher than that found in the native distribution. This could be due to hybridization in the introduced range, and/or multiple introductions from different source populations. Differences in the morphology of N. mexicana plants in the invasive range and South Africa were also observed which confirm the results of the genetic analyses. I also assessed the reproductive mode of N. mexicana cultivars/hybrids by conducting breeding system experiments and field pollinator studies. Results indicated that the cultivars are sterile, suggesting that the primary mode of reproduction is asexual via fragmentation of tubers. The main pollinators that were found to be associated with the cultivars in South Africa were honeybees, sweat bees, flies and beetles. These insect groups were the same as those that were observed in another study which was conducted on the pollinators associated with the pure N. mexicana in the native range in southern USA. Mechanical and chemical control of N. mexicana and its multiple genotypes have been applied but have not been efficient due to the fast regeneration of shoots, especially in summer. Therefore, these two management options are not long–term solutions and will also be costly due to the widespread occurrence of the hybrids in South Africa. Thus the only cost–effective, environmentally friendly, self–sustainable and long–term management option is biological control. The significant divergence between native and invasive populations of N. mexicana, as well as the possibility of numerous invasive cultivars, may limit future prospects of biological control of this species. However the differences in the root structures between native South African waterlilies, such as N. lotus and N. nouchali, and the introduced waterlilies, such as N. mexicana and its associated hybrids, may play a pivotal role in the success of biological control of the N. mexicana hybrid complex in South Africa. Natural enemies which feed on the hard tuberous roots of N. mexicana and its hybrids, as opposed to the soft bulbs of the native N. nouchali and N. lotus, should be prioritised.
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- Date Issued: 2019
The Kinshasa-based Kin ArtStudio in the Democratic Republic of Congo: visual arts spaces and the potential to challenge global art's representative and legitimizing mechanisms
- Authors: Tshilumba Mukendi, Jean-Sylvain
- Date: 2019
- Subjects: Space (Art) , Art -- Congo (Democratic Republic) , Art and globalization , Postcolonialism and the arts -- Congo (Democratic Republic) , Arts, Modern -- 21st century , Arts publicity , Arts, Modern -- 21st century -- Economic aspects , Arts, Modern -- 21st century -- Social aspects , Bondo, Vitshois Mwilambwe , Kin ArtStudio , Beauté Congo – 1926-2015 – Congo Kitoko
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/115050 , vital:34073
- Description: The emergence of visual art spaces over the past few decades on the African continent invites art practitioners, historians and critics to re-examine the conditions of production, diffusion and reception of contemporary art of Africa. In this thesis I critically engage with these conditions in relation to artworks and practices of the Democratic Republic of Congo, considering the curatorial logic that has governed the ‘global art world’. I focus on the Kin ArtStudio as my main case study. I undertook research within this art space in 2016, from the 10th of April to the 15th of June, and again from the 16th of July to the 12th of September. My position as a participant observer turned out to be as engaging as informative. The Kin ArtStudio is a Kinshasa-based visual art platform founded in 2011 by the Congolese artist Vitshois Mwilambwe Bondo. It was established out of the will to empower emerging artists in that specific context, and facilitate the negotiation that the legitimization of their creations entails in today’s global art and cultural dynamics. In order to evaluate the stakes of such negotiation, I start with reviewing the existing mechanisms, trends and networks that have legitimized visual art productions of the Democratic Republic of Congo on a global stage, as exemplified by the Beauté Congo – Congo Kitoko exhibition (2015). Then, my enquiry evolves towards specificity, towards the immediacy and the subjectivity that characterize Kinshasa's urban and socio-cultural context, and visual art practices therein. Subjectivity also applies to my four months immersive experience with that art space. Drawing from my observations, setbacks, hopes and recent academic and practical debates around contemporary art practices on the African continent, the role those art spaces can play in the curatorship, circulation, reception and commodification of contemporary art productions cannot be underestimated. While operating in lasting postcolonial settings, they are going through the negotiation of their global and translocal situatedness, which can in turn lead to new legitimizing narratives. These will more appropriately inform understandings of contemporary art practices of Africa, challenging the identifying prism sustained by the ‘global art world’.
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- Date Issued: 2019
The meaning of community: the viability of Public Sphere theory and Social Cohesion on social media groups: a reception study of the ‘Grahamstown’ Facebook Group
- Authors: Ferreira, Ettioné
- Date: 2019
- Subjects: Digital media -- Social aspects , Facebook (Firm) , Social participation -- South Africa -- Makhanda , Public sphere -- South Africa -- Makhanda , Group identity -- South Africa -- Makhanda , Grahamstown Facebook Group
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/114870 , vital:34043 , Digital media -- Social aspects , Facebook (Firm) , Social participation -- South Africa -- Makhanda , Public sphere -- South Africa -- Makhanda , Group identity -- South Africa -- Makhanda , Grahamstown Facebook Group
- Description: This study explores the meaning of community to Grahamstown’s online social media community, through a case study of the ‘Grahamstown’ Facebook group (GFG). The study explores the possibilities of social media as a public sphere and the way geographically-based social media sites might contribute to social cohesion in a community. The study explores what kinds of discussions take place on the GFG and why they are happening. It investigates whether these discussions can promote understanding and social solidarity, and whether useful deliberations are taking place, in some kind of approximation of a public sphere. Is this Group contributing to the wellbeing of the community, and how? Drawing on public sphere theory and various conceptions of the concept of social cohesion, the dissertation aims to find out how much of an impact the GFG has on Grahamstown/Makhanda inhabitants’ lives and sense of community. The study argues that with the advent of digital media, another ‘structural transformation’ in Habermasian terms, is underway, both empirically and theoretically. Through more than a dozen in-depth interviews combined with content analysis (via participant observation), the study finds that participation in and exposure to the GFG does lead, for many, to a sense of belonging and social cohesion as community members come together to act in relation to the state, local business and other institutions. The viability of ideas of highly localised (in time and space) ‘public sphericules’ as an alternative to broader more overarching concepts of a public sphere, is explored in this study. The study also suggests a typology of users, identifying the frequency, tone of voice and motives for participating on the GFG and attempts a periodisation of the GFG’s changing role in the community over the past decade.
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- Date Issued: 2019
The morphological and molecular variation of southern African Nannocharax (Characiformes: Distichodontidae), and its taxonomic implications
- Authors: Smith, Timothy
- Date: 2019
- Subjects: Nannocharax -- Africa, Southern , Distichodontidae -- Africa, Southern , Freshwater fishes -- Africa, Southern , Nannocharax -- Genetics -- Africa, Southern , Distichodontidae -- Genetics -- Africa, Southern , Freshwater fishes -- Genetics -- Africa, Southern
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/69212 , vital:29446
- Description: Nannocharax is the most species rich genus in the family Distichodontidae, being currently represented by 41 species. The genus is widely distributed across much of sub-Saharan Africa, with a range extending from the Zambezi ichthyofaunal province in the south to the Nilo-Sudan ichthyofaunal province in the north. In southern Africa, the genus is currently represented by four species, Nannocharax dageti Jerep, Vari, & Vreven, 2014, N. machadoi (Poll, 1967), N. macropterus Pellegrin, 1926, and N. multifasciatus Boulenger, 1923. Each of these species exhibit considerable intraspecific pigmentation pattern variation across their respective distribution ranges, suggesting that the current taxonomy possibly underestimates the taxonomic diversity of Nannocharax species in southern Africa. Much pigmentation pattern variation within these southern African species has been observed by both collectors and scientists in the field, prompting an investigation into the extent of this morphological variation as well as what molecular variation may occur as well. The genus displays a high degree of morphological conservatisim, making it difficult to assign external morphological characters as diagnostic. To this end, this study was conducted to determine the extent of diversity of this genus in the region, employing an integrative approach with traditional morphological analysis techniques as well as sequencing the ‘barcoding gene’, cytochrome oxidase I, testing the hypothesis that there is a greater, hidden diversity of this genus in the region than currently recognised. This study aims to identify these potential lineages and accurately map their distributions. Phylogenetic analyses were performed using maximum parsimony, maximum likelihood, and Bayesian inference, using the mitochondrial cytochrome oxidase I gene region. Massive genetic divergence was detected between populations of taxa previously considered to be singular, widely distributed species. The three approaches of phylogenetic inference used in this study yielded trees of comparable overall topology, with the exception of the maximum parsimony tree which indicated additional lineages within the southern African N. multifasciatus group. These analyses revealed four deeply divergent (1.3 – 12.3%) lineages within southern African N. macropterus, as well as two deeply divergent (0.4-14.6%) populations from the Congo ichthyofaunal region, the lineages here named “N. macropterus Congo 1” and “N. macropterus Congo 2”. Within the southern African region, two deeply divergent (10.3%) lineages of N. macropterus were identified from the Okavango River system, identified as “N. macropterus Okavango 2” lineage restricted to the Cuito-Canavale tributary, and “N. macropterus Okavango 1” distributed throughout the remainder of the Okavango system. “N. macropterus Okavango 2” shares a closer relationship with the unique lineage from the Kwanza ichthyofaunal region, named N. macropterus “Kwanza”, which itself is deeply divergent from the N. macropterus “Okavango 1”, N. macropterus “Zambezi”, N. macropterus “Congo 1” and N. macropterus “Congo 2” lineages (3.1-14.4%). Principal component analyses (PCA) and discriminant function analyses (DFA) produced overlapping clusters for all identified lineages, with the exception of the N. macropterus “Kwanza” lineage, which in all analyses clustered away from the other lineages. Analysis of variance (ANOVA) and Kruskall-Wallis tests indicated significant differences in means between character traits between lineages, however, overlap in measurements and counts occurred in all instances except between the N. macropterus “Kwanza” and N. macropterus Congo lineages. However the N. macropterus “Kwanza” lineages could be distinguished from the other lineages by generally smaller fin lengths (dorsal fin 19.5%SL vs 20.0-22.1%SL in others; pectoral fin 16.5%SL vs 20.6-21.8%SL in others; pelvic fin 18.3%SL vs 21.3-22.4) and pigmentation pattern differences. The N. macropterus species group displayed extensive pigmentation pattern variation, to the extent that five pattern grades could be used to classify them. These pattern grades, while not specific to river systems, showed patterns similar to that which was seen in the molecular analyses and could be linked to lineages with only minor overlap between them. Three lineages of N. multifasciatus were identified, with two occurring in the southern African region, each corresponding to a river system, being the N. multifasciatus “Zambezi” and N. multifasciatus “Okavango” lineages. This species group displayed shallower divergence between lineages than did the N. macropterus group, at 2.5% genetic distance. Genetic analysis inferred a closer relationship between the N. multifasciatus “Zambezi” and N. multifasciatus “Congo” lineages than with the N. multifasciatus “Okavango” lineage. Morphological PCA and DFA analyses indicated morphological divergence of the N. multifasciatus “Congo” lineage, with generally larger proportional measurements than southern African specimens (body width 12.6%SL vs 9.5-9.7%SL; body depth 26.6%SL vs 21.6-21.9%SL; head width 12.0%SL vs 10.0-10.4%SL). PCA, DFA, and measurements show a near complete overlap between the N. multifasciatus “Okavango” and N. multifasciatus “Zambezi” lineages. Pigmentation pattern variation occurred within this group, but none that could be assigned to a particular lineage. The N. machadoi species group in southern Africa consists of five lineages: N. machadoi “Zambezi 1”, N. machadoi “Zambezi 2”, N. machadoi “Kafue 1”, N. machadoi “Kafue 2”, and N. machadoi “Okavango”. This group displayed shallower genetic divergence between lineages than the other southern African Nannocharax species groups (0.4-1.3%). This shallow genetic divergence is paralleled by near complete morphological overlap, with PCA and DFA producing overlapping clusters, and measurements, meristics, and pigmentation pattern metrics consisting of very similar values for the lineages. These results indicate that what is considered to be “N. macropterus” in southern Africa should not be named as such. The N. macropterus “Zambezi” and the N. macropterus “Okavango 1” lineages, are misidentifications of Nannocharax dageti. Other “N. macropterus” from the southern African region possesses fewer circumpeduncular scales than the true N. macropterus as described by Pellegrin (1926), and require taxonomic re-evaluation, each here being recognised as a unique lineage with species status, here named N. macropterus “Okavango 2” and N. macropterus “Kwanza”. In particular, N. macropterus “Kwanza” displays deep genetic divergence as well as morphological dissimilarity with the other southern African “N. macropterus” groups. Nannocharax fasciolaris and N. monardi are here placed as junior synonyms of N. multifasciatus, owing to vast overlaps in measurements and character counts of these species and N. multifasciatus, which is also known to occur within the same geographical distribution, as well as dubious arguments from the original publications in delineating these species from N. multifasciatus. Therefore, there is insufficient evidence indicating the presence of multiple species originating from the Okavango system, where it is here indicated that only a single lineage of banded, adipose fin-bearing Nannocharax occurs, namely N. multifasciatus “Okavango”.
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- Date Issued: 2019
The morphotactic constraints of verbal extensions in isiXhosa
- Authors: Mkabile, Hlumela
- Date: 2019
- Subjects: Xhosa language -- Grammar
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/92849 , vital:30749
- Description: Bantu verbal suffixes, also known as extensions, follow a rather rigid pattern when they attach to the verb. Studies (e.g. Hyman 2002, Good 2005, 2007, among others) have shown that the order followed by these extensions is: Causative, Applicative, Reciprocal, Passive (CARP). Although this pattern is widespread across Bantu, some variations in the ordering of these extensions have been observed in some languages (Kathupa 1991, Simango 1995, Sibanda 2004, among others), which suggests that the template is not as rigid as one might think. This study investigated the morphotactic constraints between four verbal extensions in isiXhosa, the Causative, Applicative, Reciprocal and Passive. It focused on the morphotactics of the transitivising extensions (Causative and Applicative) in the first instance, and morphotactics of the detransitivising extensions (Reciprocal and Passive) in the second instance. The study found that although the co-occurrence of causatives and applicatives is a regular feature in Bantu languages, isiXhosa has restrictions on the co-occurrence of these extensions on some verbs. The study also found that although Causative-Applicative is the expected order the language permits Applicative-Causative in certain contexts. With respect to the detransitivising extensions, the study revealed that there are limited contexts in which these extensions co-occur and, crucially, that these extensions are freely ordered in the language.
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- Date Issued: 2019