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Elucidating the Molecular Basis of the Interaction between the β2-integrin, αXβ2, and the low-affinity IgE Receptor, CD23

  • Authors: Clarke, Stephen
  • Date: 2019
  • Subjects: CD23 antigen , Immune response Cellular immunity Molecular immunology
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/37990 , vital:34277
  • Description: The low affinity IgE receptor, CD23, is involved in a myriad of immune reactions. It is not only a receptor for IgE, but also functions in the regulation of IgE synthesis, isotype switching in B cells, and induction of the inflammatory response. These effector functions of CD23 arise through its interaction with another leukocyte-specific cell surface receptor – the β2 integrin subfamily. However, this interaction has not been fully described. It has been shown that CD23 is capable of interacting with the β3 and β5 integrin β-subunit of integrins via a basic RKC motif in a metal cation-independent fashion. The currently proposed mechanism for the interaction between CD23 and the integrin superfamily was applied to the β2 integrin subfamily. In this study the interaction was probed for whether or not the RKC motif governs the interaction as well. This was done by performing bioinformatics docking predictions between the CD23 and αXβ2 integrin proteins. This revealed that in the absence of cations, the RKC motif is involved in interaction with the integrin αI domain. However, since physiologically integrin activity has been shown to be regulated by metal cations, docking predictions were also performed in the presence of such cations. This showed the interaction to involve novel acidic motifs within the CD23 protein, GEF and LDL. This same pattern of interaction was seen in docking predictions between CD23 and the β2- and β3I-like domains. To further investigate, recombinant proteins of sCD23 and the αXI domain were produced using E. coli expression systems. The DNA sequence was mutated to produce mutant versions of the CD23 RKC and GEF motifs as well as a high-affinity locked αXI domain. These proteins were used in subsequent SPR spectroscopy analysis of the binding affinity between immobilised integrin and CD23 analyte. It was shown that the mutation within the RKC motif reduced the binding affinity under cation-independence, especially when the Arg172 residue was substituted. However binding was not completely lost. This result was supported by synthetic peptides containing the same RKC motif and substitutions. These showed complete loss in binding in the double RKΔAA substitution, suggesting the involvement of other residues in the RKC-dependent interaction. In contrast, under cation dependence, the RKC motif substitutions showed no effect on binding affinity, while the GEF motif substitution exhibited near complete loss in binding. This same effect on binding was validated by U937 cell-based ELISA using live cells. This showed decreased capture of differentiated U937 cells, expressing the αXβ2 integrin, by immobilised recombinant sCD23 protein. In this study it was noted that, 2 contrary to the SPR analysis, metal cations allowed for a higher titre of cells to be captured in comparison to the cation-free binding.
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  • Date Issued: 2019

An analysis of poetic syntax with special reference to Stockenström’s The Wisdom of Water (2007)

  • Authors: Murdoch, Alan
  • Date: 2019
  • Subjects: Poetics , Poetry -- History and criticism Afrikaans poetry -- 21st century
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10948/41581 , vital:36538
  • Description: Poetry, by its very nature, is different to prose. Through ostranenie, the poet tries to foreground his or her message (meaning). Ostranenie is defined as follows: ‘A neologism, it implies two kinds of action: making strange, and pushing aside. Consistent with this double meaning, the concept refers to the techniques writers use to transform ordinary language into poetic language’ (www.oxfordreference.com). Gräbe (1997: 25) states: ‘The recognition of a difference between ordinary or normal language on the one hand, and “unusual” or “different” language use on the other hand is dependent upon the distinction […] between “automatisation” and “foregrounding.”’ This study will look at poetry, specifically that of Wilma Stockenström in The Wisdom of Water (2007), through the lens of syntax.The aim of this study is to determine the unique contribution of syntactic strategies for analysing and interpreting poetry and how they aid the poet in foregrounding his or her intended meaning. The strategies investigated are those detailed by Ina Gräbe in Syntax in Poetry (1997), namely the violation of grammatical rules in poetic language (specifically displacement, deletion and selectional deviation), the exploitation of forms of repetition in syntactic pattern formation (specifically coupling, parallelism and elaboration) and finally syntactic units and typographic demarcations (specifically the relationship between sentence and line and, the relationship between sentence and stanza). Through qualitative analysis, this study performs a syntactical structure analysis of Stockenström’s poetry in The Wisdom of Water (2007) and shows how the use and effect of Gräbe’s syntactic strategies can foreground a poet’s intended meaning. It will further show the way in which such a linguistic analysis can provide insight into the poet’s meaning, that might not otherwise have been apparent to a reader.
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  • Date Issued: 2019

Experiences of female adolescents attending community health centres regarding the use of contraceptives in Buffalo City Health District

  • Authors: Summerton, Glenda
  • Date: 2019
  • Subjects: Contraceptives -- South Africa -- Buffalo City Metropolitan Municipality , Teenagers -- Sexual behavior -- South Africa -- Eastern Cape Teenagers -- South Africa -- Eastern Cape -- Attitudes Adolescence -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MCur
  • Identifier: http://hdl.handle.net/10948/43968 , vital:37088
  • Description: Family planning is a broad term that encompasses the provision of contraceptive methods to sexually active women or girls and includes fertility planning. Despite the widespread availability of knowledge about modern contraception, many young people do not use contraception or use it inconsistently and incorrectly. The purpose of the study was to explore and describe the experiences of female adolescents attending community health centres regarding contraceptive usage. The study also intended to provide recommendations to the district health office and facility managers at community health centres regarding care and support of adolescents concerning their use of contraceptives. The study utilised a qualitative, exploratory, descriptive, and contextual research design. The target group comprised of female adolescents attending community health centres in Buffalo City Health District, for contraceptive and adolescentfriendly services. A purposeful sampling technique was used to select the community health centres in the study and the researcher used convenience sampling to select participants at each community health centre. The researcher used semi-structured interviews to interview the participants regarding their experiences of using contraceptives. Tesch’s thematic method of data analysis was used to analyse the data. The researcher adhered to all the ethical principles of the Belmont Report while conducting the study. The analysed data indicated the issue of access to contraceptives and their usage as a challenge to many female adolescents attending the community health centres in Buffalo City Municipality. Adolescents expressed a range of negative emotions regarding the consequences of not using contraceptives and some also complained about the side effects of using contraception. Some adolescents felt that nurses did not always provide them with quality care, while others experienced receiving patient-centred, holistic care from clinic nurses, as well as health education regarding contraceptive usage from nurses and life orientation teachers. However, female adolescents called for an increase in reproductive health education at clinics and hospitals. They also expressed the need for regular school involvement regarding the education of adolescents on the various aspects of contraceptive usage. Hence, it is hoped that the recommendations from this study will assist the DoH to better assist adolescent females with contraceptive usage.
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  • Date Issued: 2019

Novel potential antimalarials through drug repurposing and multitargeting: a Computational Approach

  • Authors: Diallo, Bakary N , Lobb, Kevin A , Tastan Bishop, Özlem
  • Date: 2019
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/162676 , vital:40972 , https://doi.org/10.21955/aasopenres.1114955.1
  • Description: This study aims to identify potential antimalarials from Food and Drug Administration (FDA) approved drugs.
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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.
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  • Date Issued: 2019

Bolvedere: a scalable network flow threat analysis system

  • Authors: Herbert, Alan
  • Date: 2019
  • Subjects: Bolvedere (Computer network analysis system) , Computer networks -- Scalability , Computer networks -- Measurement , Computer networks -- Security measures , Telecommunication -- Traffic -- Measurement
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/71557 , vital:29873
  • Description: Since the advent of the Internet, and its public availability in the late 90’s, there have been significant advancements to network technologies and thus a significant increase of the bandwidth available to network users, both human and automated. Although this growth is of great value to network users, it has led to an increase in malicious network-based activities and it is theorized that, as more services become available on the Internet, the volume of such activities will continue to grow. Because of this, there is a need to monitor, comprehend, discern, understand and (where needed) respond to events on networks worldwide. Although this line of thought is simple in its reasoning, undertaking such a task is no small feat. Full packet analysis is a method of network surveillance that seeks out specific characteristics within network traffic that may tell of malicious activity or anomalies in regular network usage. It is carried out within firewalls and implemented through packet classification. In the context of the networks that make up the Internet, this form of packet analysis has become infeasible, as the volume of traffic introduced onto these networks every day is so large that there are simply not enough processing resources to perform such a task on every packet in real time. One could combat this problem by performing post-incident forensics; archiving packets and processing them later. However, as one cannot process all incoming packets, the archive will eventually run out of space. Full packet analysis is also hindered by the fact that some existing, commonly-used solutions are designed around a single host and single thread of execution, an outdated approach that is far slower than necessary on current computing technology. This research explores the conceptual design and implementation of a scalable network traffic analysis system named Bolvedere. Analysis performed by Bolvedere simply asks whether the existence of a connection, coupled with its associated metadata, is enough to conclude something meaningful about that connection. This idea draws away from the traditional processing of every single byte in every single packet monitored on a network link (Deep Packet Inspection) through the concept of working with connection flows. Bolvedere performs its work by leveraging the NetFlow version 9 and IPFIX protocols, but is not limited to these. It is implemented using a modular approach that allows for either complete execution of the system on a single host or the horizontal scaling out of subsystems on multiple hosts. The use of multiple hosts is achieved through the implementation of Zero Message Queue (ZMQ). This allows for Bolvedre to horizontally scale out, which results in an increase in processing resources and thus an increase in analysis throughput. This is due to ease of interprocess communications provided by ZMQ. Many underlying mechanisms in Bolvedere have been automated. This is intended to make the system more userfriendly, as the user need only tell Bolvedere what information they wish to analyse, and the system will then rebuild itself in order to achieve this required task. Bolvedere has also been hardware-accelerated through the use of Field-Programmable Gate Array (FPGA) technologies, which more than doubled the total throughput of the system.
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  • Date Issued: 2019

Chiral Modulation from Molecular to Macroscopic levels by synthetic chiral-amide-bonded porphyrin dimers

  • Authors: Liang, Xu , Qin, Mingfeng , Zhang, Xiaomei , Mack, John , Soy, Rodah , Nyokong, Tebello , Zhu, Weihua
  • Date: 2019
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/186802 , vital:44535 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.107637"
  • Description: Six different nanoarchitectures were constructed by a series of synthetic bio-inspired chiral porphyrin dimers through molecular self-assembly behaviour. A plausible mechanism of chiral expression from the molecular to the macroscopic levels was investigated through an analysis of the optical spectroscopy and theoretical calculations.
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  • Date Issued: 2019

Professional nurses’ experiences regarding the management of patients on drug-resistant tuberculosis treatment at primary health care clinics

  • Authors: Kramer, Mercia Virginia
  • Date: 2019
  • Subjects: Drug-resistant tuberculosis -- Treatment
  • Language: English
  • Type: Thesis , Masters , MCur
  • Identifier: http://hdl.handle.net/10948/44703 , vital:38146
  • Description: Drug-resistant tuberculosis (DR-TB) is a significant health burden in South Africa because it challenges the control of TB in the community since the decentralization of treatment. As a community health nurse who has previously worked in clinics in the Nelson Mandela Bay Health District (NMBHD), the researcher observed numerous challenges resulting from the decentralization of DR-TB in the community. The workload of professional nurses, who are the first point of contact for patients accessing primary health care services, has increased significantly since the management of patients on DR-TB treatment has become part of their responsibilities due to the previous mentioned decentralization. The researcher was therefore motivated to establish how professional nurses at primary health care (PHC) clinics experience the management of patients who are on DR-TB treatment. The study employed a qualitative, exploratory, descriptive and contextual design. The research population consisted of professional nurses who were managing the DR-TB programme in PHC clinics in the NMBHD. The appropriate research sample was identified and selected using a non-probability, purposive technique. In-dept interviews were used to collect the data, and Tesch’s model was used for data analysis. The researcher adhered to the ethical considerations of research throughout the study, and ensured the trustworthiness of the data by using the criteria of credibility, transferability, dependability and conformability. The study findings revealed that the participants had diverse experiences of the management of DR-TB. In this regard, the professional nurses expressed both negative and positive experiences. Two themes emerged from the study. Theme 1 and its subthemes related to the challenges encountered when managing patients diagnosed with DR-TB. Theme 2 and its subthemes related to the positive aspects of managing patients diagnosed with DR-TB. In conclusion the study highlighted that professional nurses had fear and real challenges, but also experienced positive experiences of the management of patients on DR-TB treatment. In light of the study findings, recommendations were made regarding nursing education, nursing practice and nursing research.
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  • Date Issued: 2019

Factors affecting female condom use in Buffalo City Metropolitan, Eastern Cape, South Africa

  • Authors: Bunu, Nosipho
  • Date: 2019
  • Subjects: Condom use -- South Africa Sexually transmitted diseases
  • Language: English
  • Type: Thesis , Masters , M Cur
  • Identifier: http://hdl.handle.net/10353/12959 , vital:39411
  • Description: Introduction: The female condom was introduced so many years after the male condom was introduced as an additional intervention to prevent sexually transmitted diseases and HIV/AIDS. The purpose of the study was to explore and describe the factors affecting female condom use in Buffalo City Metropolitan, Eastern Cape. Method: Quantitative descriptive and contextual research designs were used to enable the researcher to gain knowledge and insights on female condom use. The population of the study was sexually active women between ages of 15-49 years, living in Reeston community of Buffalo City Municipality in the Eastern Cape Province. Convenient sampling was used to recruit the respondents with 599-sample size and data was collected using questionnaires. Ethical considerations were considered throughout the study. Data was analysed using Statistical Package for the Social Sciences (SPSS version 22) and summarised using tables, graphs and descriptive statistics. Results: The findings of the study were minimal use of female condom because of poor marketing strategies towards female condoms despite the government intervention. The attitude of sexually active women towards female condom was positive, but minimal knowledge, inaccessibility and unavailability of female condoms hinder its use. Conclusion and Recommendation: The study recommended health education through campaigns and counselling about female condom use and their benefits to all age groups of women who are sexually active. The government and stakeholders should promote the condom uptake, accessibility and availability in every public place. Department of Health, Education should have empowered the community at large on how to promote female condom use and improve the distribution of both male/ female condoms to schools and public place.
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  • Date Issued: 2019

Nonlinear optical responses of carbazole-substituted phthalocyanines conjugated to graphene quantum dots and in thin films

  • Authors: Majeed, Shereen A , Nwaji, Njemuwa , Mack, John , Nyokong, Tebello , Makhseed, Saad
  • Date: 2019
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/186938 , vital:44549 , xlink:href="https://doi.org/10.1016/j.jlumin.2019.04.034"
  • Description: Three different phthalocyanine complexes substituted with carbazoles were conjugated to graphene quantum dots (GQDs) through π–π stacking. The morphologies, sizes, and crystallinities of the nanoconjugates were determined using Raman spectroscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray diffraction. The nonlinear optical (NLO) properties of the metallophthalocyanines alone and when conjugated to the GQD nanomaterial in different solvents, as well as after having been embedded in thin films, were studied. The effects of the different substituents and solvents on the NLO properties of the metallophthalocyanines were evaluated. Enhancements in the photophysical properties of the complexes upon conjugation with the nanomaterial were observed. Fluorescence quantum yields, fluorescence lifetimes, triplet quantum yields, and triplet lifetimes were measured for the complexes, and for their conjugates in DMSO.
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  • Date Issued: 2019

Static and bootstrapped neuro-simulation for complex robots in evolutionary robotics

  • Authors: Woodford, Grant Warren
  • Date: 2019
  • Subjects: Robotics
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/44656 , vital:38172
  • Description: Evolutionary Robotics (ER) is a field of study focused on the automatic development of controllers and robot morphologies. Evolving controllers on real-world hardware is time-consuming and can damage hardware through wear. Robotic simulators can be used as an alternative to a real-world robot in order to speed up the ER process. Most simulation techniques in practice use physics-based models that rely on an understanding of the robotic system in question. Developing effective physics-based simulators is time consuming and requires a significant level of specialised knowledge. A lengthy simulator development and tuning process is typically required before the ER process can begin. Artificial Neural Networks simulators (SNNs) can be used as an alternative to a physics based simulation approach. SNNs are simple to construct, do not require significant levels of prior knowledge of the robotic system, are computationally efficient and can be highly accurate. Two types of ER approaches utilising SNNs exist. The Static Neuro-Simulation (SNS) approach involves developing SNNs before the ER process where these SNNs are used instead of a physics-based simulator. Alternatively, SNNs can be developed during the ER process, called the Bootstrapped Neuro-Simulation (BNS) approach. Prior work investigating SNNs has largely been limited to simple robots. A complex robot has many degrees of freedom and ifa low-level controller design is used, the solution search space is high-dimensional and difficult to traverse. Prior work investigating the SNS and BNS approaches have mostly relied on simplified controller designs which rely on built-in prior knowledge of intended robot behaviours. This research uses low-level controller designs which in turn rely on low level simulators. Most ER studies are conducted on a single type of robot morphology. This research investigates the SNS and BNS approaches on two significantly different classes of robots. A Hexapod and Snake robot are used to study the SNS and BNS approaches. The Hexapod robot exhibits limbed, walking behaviours. The Snake robot is limbless and generates crawling behaviours. Demonstrating the viability of the SNS and BNS approaches for two different classes of robots provides strong evidence that the tested approaches are likely viable on other classes of robots. Various proposed improvements to the SNS and BNS approaches are investigated. The Results demonstrate that the SNS and BNS approaches are viable when applied to Hexapod and Snake robots without restricting controller designs to those with significant levels of built-in prior knowledge of robot behaviours. SNNs configured in ensembles improve the likely performance outcomes of solutions. The expected benefit of adding simulator noise during the evolutionary process were not as pronounced for problems investigated in this work.
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  • Date Issued: 2019

Expanding learning in clergy leadership formation in an Anglican Church Province in Southern Africa: a critical realist study

  • Authors: Chinganga, Percy
  • Date: 2019
  • Subjects: Leadership -- Africa, Southern -- Religious aspects -- Christianity , Church management -- Africa, Southern , Critical realism , Educational leadership , Anglican Church of Southern Africa
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/92258 , vital:30704
  • Description: The focus of this study was to investigate the kind of learning that happened when participants involved in clergy leadership formation programmes and activities in the Anglican Church of Southern Africa (ACSA) engaged in their responsibilities as a collective. Further, the research sought to explore collaborative and transforming practices in ACSA clergy leadership formation programmes and activities which could be expanded through learning. The study is premised on an investigation of the historical foundations of Christian leadership formation processes which sought to establish clergy leadership formation models relevant to ACSA (the context of the study) from inception (1848) to date (2017). This entailed investigating how the developments which have happened in the church from its inception in the New Testament times through the Medieval and Reformation periods, have contributed to the emergence of distinct Christian leadership formation models which have formed the basis of clergy leadership formation in ACSA. Accordingly, the study highlighted key issues relating to clergy leadership formation which are discernible in the different historical phases of the life and work of the church with the objective of establishing how ACSA, through expansive learning, could transform her current clergy leadership formation model(s) towards collaborative and transforming practices. The concept of expansive learning, drawn from Cultural Historical Activity Theory (CHAT), was used in the study as a methodological tool to create an environment where research participants (formators) from several dioceses would engage in collective work activities which would surface contradictions relating to how clergy leadership formation programmes and activities were understood and facilitated in ACSA. In response to the surfaced contradictions, the study engaged research participants in Change Laboratory Workshops whose goal was to transform the organisation (ACSA) in two particular ways: empowerment of participants (formators) with conceptual tools relevant to their responsibilities in clergy leadership formation programmes and activities in ACSA, and improvement of organisational cultural practices, that is, the manner in which ACSA ought to conceptualise, design, plan, facilitate and manage clergy leadership formation programmes and activities. The latter brought into the discourse the need for participants (formators) to select and employ methodologies, methods, approaches and resources relevant to the southern African context where ACSA is located even though the study also acknowledged the influence of other Anglican Church contexts on what happened at the local level. In order to decipher meaning out of investigated phenomena about clergy leadership formation in ACSA, the study employed the critical realist “underlabouring” philosophy advanced by theorists such as Bhaskar to surface underlying mechanisms that exist at the level of the “real” in order to understand the causes of particular events and experiences as they manifest in the “actual” and “empirical” domains of the world, ACSA in the case of the study. In particular, the study engaged critically the opinion deliberated by critical realists concerning the interplay between structure and agency in relation to the responsibilities of the research participants (formators) in ACSA clergy leadership formation programmes and activities. For instance, the study had an interest in investigating why bishops (principal formators in ACSA) exercised their episcopal authority in the manner they do and why individual formators were concerned about particular issues which relate to the facilitation of clergy leadership formation in ACSA (agential reflexivity/subjectivity). The study observed that, in the case of diocesan bishops, critical realists would argue that, by virtue of the authority which comes with their responsibilities (agency), they have the power to influence transformation of practices in clergy leadership formation in ACSA at any given point in time. The flip side of the discourse was also taken note of: that some bishops, for reasons known to themselves and their predecessors, are often reluctant to embrace new ideas relating to clergy leadership formation practices in their dioceses. Further, through critical realist lens, the study concluded that Canons, Vision and Mission statements, Acts, and structures such as Synod of Bishops, Provincial Synod, ABoTE, Cott, and TfM structurally shape ACSA, thus providing the organisation with a stable ontology which ought to direct, regulate and control the manner in which clergy leadership formation programmes and activities were conceptualised, designed, planned, facilitated and managed. As such, the study had an interest in establishing what would happen, in relation to clergy leadership formation practices in ACSA, when these structures would have been activated? Beyond that, in view of the goal of the study, it was enquired how expansive learning processes could be helpful in responding to the research findings towards exploring collaborative and transforming clergy leadership formation practices in ACSA. Drawing from the conceptual framework which was carved in the study on the basis of the theoretical tools (critical realism and educational leadership theory) and methodological tools (CHAT orientated concepts) undergirded by the Vygotskian theorisation of human consciousness development, the study concluded that clergy leadership formation is a collaborative activity which calls for the recognition, appreciation and utilisation of available expertise in ACSA and provision of a platform where participants (formators) could engage collectively on issues relating to their work with the objective of building each other up in knowledge and skills (expansive learning) towards realisation of the goals and objectives of the organisation. Diverse understandings (contradictions) of what needed to be prioritised in the facilitation of clergy leadership formation in ACSA would be considered as a positive rather than a negative. Ultimately, through the use of inductive, abductive and retroductive modes of inference, the study modelled a transforming, transformational, transformative, embodied and incarnational model of clergy leadership formation which ACSA could consider using in future deliberations on the object of study particularly in relation to the key research findings across the case studies which were used in the study.
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  • Date Issued: 2019

Computational analysis of missense mutations from the human Macrophage Migration Inhibitory Factor (MIF) protein by Molecular Dynamics Simulations and Dynamic Residue Network Analysis:

  • Authors: Kimuda, Phillip M , Brown, David K , Amamuddy, Olivier S , Ross, Caroline J , Matovu, Enock , Tastan Bishop, Özlem
  • Date: 2019
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/163238 , vital:41021 , https://doi.org/10.21955/aasopenres.1115054.1
  • Description: Missense mutations are changes in the DNA that result in a change in the amino acid sequence. Depending on their location within the protein they can have a negative impact on how the protein functions. This is especially important for proteins involved in the body’s response to infection and diseases. Macrophage migration inhibitory factor (MIF) is one such protein that functions to recruit white blood cells to sites of inflammation.
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  • Date Issued: 2019

An exploratory case study of accelerator programmes in the Republic of South Africa

  • Authors: Mametse, Mmankitseng Lerato
  • Date: 2019
  • Language: English
  • Type: text , Thesis , Masters , MBA
  • Identifier: http://hdl.handle.net/10962/92639 , vital:30737
  • Description: South Africa is facing a challenge of poverty, unemployment and low growth. Government has identified the small and medium-sized business (SME) sector as one of the ways through which to combat these challenges. Government has also set up programmes and agencies to support SMEs in their search for funding and other kinds of support. South Africa, however, has one of the highest rates of SME failures in the world, with the majority not surviving beyond three years. Alternative interventions are therefore required to support South Africa’s SMEs to become sustainable companies beyond three years and to contribute positively to economic growth, poverty alleviation and job creation. This paper explores one kind of intervention that has been used internationally and that is increasingly being adopted in South Africa. Accelerator programmes, aimed at supporting start-ups to get to the next level of their development, have been growing in numbers around the world, trying to replicate the success of the original accelerator programme – the Y Combinator – which was responsible for the success of household names such as Airbnb and Dropbox. Accelerator programmes help start-up companies define and build their initial products, identify promising customer segments, and secure resources, including capital and employees. By making these necessary resources available to start-ups, it may be possible to ensure that fewer start-ups fail and more SMEs remain sustainable into the future. Several accelerator programmes have been founded in South Africa, all with a similar aim: to accelerate the development of start-ups that have the potential to grow exponentially given access to the right resources. This paper examines how South African accelerator programmes work in terms of the key resources made available to the start-ups that participate in their programmes. An increasing number of academic papers have been written on accelerator programmes internationally, but little information is available for the South African context. This research study investigated the phenomenon of accelerator programmes in South Africa through the lens of Resource-based Theory. The theory posits that, in order to gain a sustained competitive advantage, companies need to utilise their resources (including physical, human and organisational) in a manner that is effective and efficient, both internally and externally. The research answers the following questions: How do accelerator programmes work in South Africa? What value (in terms of resources offered) do they claim to bring to start-ups that go through their accelerator programmes? An exploratory case study method was selected to understand the phenomenon of accelerator programmes in South Africa. Purposeful sampling was used in the selection of accelerator programmes, as it allows for the selection of information-rich cases. The research findings indicate that accelerator programmes in South Africa follow the structure of providing start-ups, over a period between three months and one year, with resources that will assist them to be successful into the future. The investigation finds that human and financial resources are some of the most valuable resources that accelerator programmes provide to start-ups to help progress these start-ups to their next level of development. The most important resource is mentorship from knowledgeable industry players who are themselves entrepreneurs. Access to networks to gain access to the market, as well as funding, is also made available by accelerator programmes. This investigation provides a glimpse of the accelerator programme phenomenon in South Africa and highlights the important role that mentorship from experienced entrepreneurs, and access to markets and funding, play in the development of start-ups.
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  • Date Issued: 2019

Influence of destination familiarity and destination image on the intention to revisit East London

  • Authors: Nyezwa, Abegail Noluthando
  • Date: 2019
  • Subjects: Tourism -- South Africa -- East London -- Marketing , Tourism -- South Africa -- East London
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: http://hdl.handle.net/10948/42781 , vital:36691
  • Description: Tourists have a tendency of revisiting a destination when they are pleased with certain features encountered during their first visit. In some cases, even though the visitors are happy, they do not return to the same destination because they want to discover other destinations, whereas fewer satisfied tourists do return to the same destination and become repeat visitors. In order to remain internationally competitive, it is essential for destinations to design and implement marketing strategies which will assist in attracting the preferred product positioning in target markets. Destinations should always distinguish themselves from their competitors. The aim of this study was to investigate the extent to which destination familiarity and destination image influence the intention to revisit East London. A quantitative research method was adopted in order to test the relationships depicted in the hypothesised model. A sample was drawn using convenience sampling techniques. In total, 62 questionnaires were distributed to tourists who had revisited East London. The study discovered that most of the respondents were employed and educated. The study made use of the survey methodology and a structured questionnaire was used in order to collect data from respondents. All the questionnaires were returned. Cronbach’s alpha coefficient was used to test reliability of multiple-item scales. Only two variables had Cronbach’s alpha scores above 0.60. and one had a score of 0.40 and that is unacceptable. The study revealed that a majority of respondents strongly agree that quality beaches, entertainment and sport are factors which will encourage them to revisit East London. This study revealed that there is a significant relationship between Destination Familiarity and Traveller’s Attitude. The study revealed that only few respondents viewed East London as expensive. The study recommended that the city examine its natural attractions, upgrade the shopping facilities and continuously maintain the qualities of beaches, initiating new fairs and festivals, making sure that local transport is reliable and safe. In order to be globally competitive, management need to gather intelligence in terms of how other countries globally use to attract repeat tourist visitation.
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  • Date Issued: 2019

Teaching NCS (CAPS) FET mathematics: a comparison between an offline techno-blended Model and a traditional approach

  • Authors: Munemo, Noname
  • Date: 2019
  • Subjects: Mathematics -- Study and teaching (Secondary) , Mathematics -- Study and teaching (Higher) -- South Africa Blended learning Educational innovations
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: http://hdl.handle.net/10948/41614 , vital:36545
  • Description: This research is a comparative research study that compares the way learning has taken place when selected mathematics topics were taught to two groups of Grade 11 Mathematics learners. An offline Techno-Blended Teaching and Learning Model was used for one group, while the other group was taught without the integration of technology. The cognitive and affective impact of the use of technology when an offline Techno-Blended T&L Model was followed, was compared to a corresponding impact of an approach where no technology was integrated during the teaching of the topics. The research study involved teachers and selected learners in the Mathematics classes from four different high schools selected from two urban districts in the Eastern Cape Province in South Africa. The curriculum topics that the research focused on were Euclidean Geometry and Trigonometry.
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  • Date Issued: 2019

Testing the thermal limits of Eccritotarsus catarinensis: a case of thermal plasticity

  • Authors: Porter, Jordan D , Owen, Candice A , Compton, Stephen G , Coetzee, Julie A
  • Date: 2019
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/417533 , vital:71461 , xlink:href="https://doi.org/10.1080/09583157.2019.1572712"
  • Description: Water hyacinth is considered the most damaging aquatic weed in South Africa. The success of biocontrol initiatives against the weed varies nation-wide, but control remains generally unattainable in higher altitude, temperate regions. Eccritotarsus catarinensis (Hemiptera: Miridae) is a biocontrol agent of water hyacinth that was first released in South Africa in 1996. By 2011, it was established at over 30 sites across the country. These include the Kubusi River, a site with a temperate climate where agent establishment and persistence was unexpected. This study compared the critical thermal limits of the Kubusi River insect population with a laboratory-reared culture to determine whether any physiological plasticity was evident that could account for its unexpected establishment. There were no significant differences in critical thermal maxima (CTmax) or minima (CTmin) between sexes, while the effect of rate of temperature change on the thermal parameters in the experiments had a significant impact in some trials. Both CTmax and CTmin differed significantly between the two populations, with the field individuals tolerating significantly lower temperatures (CTmin: −0.3°C ± 0.063 [SE], CTmax: 42.8°C ± 0.155 [SE]) than those maintained in the laboratory (CTmin: 1.1°C ± 0.054 [SE], CTmax: 44.9°C ± 0.196 [SE]). Acclimation of each population to the environmental conditions typical of the other for a five-day period illustrated that short-term acclimation accounted for some, but not all of the variation between their lower thermal limits. This study provides evidence for the first cold-adapted strain of E. catarinensis in the field, with potential value for introduction into other colder regions where water hyacinth control is currently unattainable.
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  • Date Issued: 2019

Grabcuts for image segmentation: A comparative study of clustering techniques

  • Authors: Manzi, Nozuko Zuleika
  • Date: 2019
  • Subjects: Algorithms Computer graphics
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10353/14494 , vital:39995
  • Description: Image segmentation is the partitioning of a digital image into small segments such as pixels or sets of pixels. It is significant as it allows for the visualization of structures of interest, removing unnecessary information. In addition, image segmentation is used in many fields like, for instance healthcare for image surgery, construction, etc. as it enables structure analysis. Segmentation of images can be computationally expensive especially when a large dataset is used, thus the importance of fast and effective segmentation algorithms is realised. This method is used to locate objects and boundaries (i.e. foreground and background) in images. The aim of this study is to provide a comparison of clustering techniques that would allow the Grabcuts for image segmentation algorithm to be effective and inexpensive. The Grabcuts based method, which is an extension of the graph cut based method, has been instrumental in solving many problems in computer vision i.e. image restoration, image segmentation, object recognition, tracking and analysis. According to Ramirez,et.al [47], the Grabcuts approach is an iterative and minimal user interaction algorithm as it chooses a segmentation by iteratively revising the foreground and background pixels assignments. The method uses min-cut/ max-flow algorithm to segment digital images proposed by Boykov and Jolly [9]. The input of this approach is a digital image with a selected v region of interest (ROI). The ROI is selected using a rectangular bounding box. The pixels inside the bounding box are assigned to the foreground, while the others are assigned to the background. In this study, the Grabcuts for image segmentation algorithm designed by [48] with a Gaussian Mixture Model (GMM) based on the Kmeans and Kmedoids clustering techniques are developed and compared. In addition, the algorithms developed are allowed to run on the Central Processing Unit (CPU) under two scenarios. Scenario 1 involves allowing the Kmeans and Kmedoids clustering techniques to the Squared Euclidean distance measures to calculate the similarities and dissimilarities in pixels in an image. In scenario 2, the Kmeans and Kmedoids clustering techniques will use the City Block distance measure to calculate similarities as well as dissimilarities between pixels in a given image. The same images from the Berkeley Segmentation Dataset and Benchmark 500 were used as input to the algorithms and the number of clusters, K, was varied from 2 to 5. It was observed that the Kmeans clustering technique outperformed the Kmedoids clustering technique under the two scenarios for all the test images with K varied from 2 to 5, in terms of runtime required. In addition, the Kmeans clustering technique obtained more compact and separate clusters under scenario 1, than its counterpart. On the other hand, the Kmedoids obtained more compact and separate clusters than the Kmeans clustering technique under scenario 2. The silhouette validity index favoured the smallest number of clusters for both clustering techniques as it suggested the optimal number of clusters for the Kmeans and Kmedoids clustering techniques under the two scenarios was 2. Although the Kmeans required less computation time than vi its counterpart, the generation of foreground and background took longer for the GMM based on Kmeans than it did for the GMM based on Kmedoids clustering technique. Furthermore, the Grabcuts for image segmentation algorithm with a GMM based on the Kmedoids clustering technique was computationally less expensive than the Grabcuts for image segmentation algorithm with a GMM based on the Kmeans clustering technique. This was observed to be true under both scenario 1 and 2. The Grabcuts for image with the GMM based on the Kmeans clustering techniques obtained slightly better segmentation results when the visual quality is concerned, than its counterpart under the two scenarios considered. On the other hand, the BFscores showed that the Grabcuts for image segmentation algorithm with the GMM based on Kmedoids produces images with higher BF-scores than its counterpart when K was varied from 2 to 5 for most of the test images. In addition, most of the images obtained the majority of their best segmentation results when K=2. This was observed to be true under scenario 1 as well as scenario 2. Therefore, the Kmedoids clustering technique under scenario 2 with K=2 would be the best option for the segmentation of difficult images in BSDS500. This is due to its ability to generate GMMs and segment difficult images more efficiently (i.e. time complexity, higher BF-scores, more under segmented rather than over segmented images, inter alia.) while producing comparable visual segmentation results to those obtained by the Grabcuts for image segmentation: GMM-Kmeans.
  • Full Text:
  • Date Issued: 2019

Synthesis, characterisation and spectroscopic studies of diazine-N-oxide complexes of iron(II) towards the development of sensors

  • Authors: Mpiti, Unako Bongani
  • Date: 2019
  • Subjects: Diazines , Ligands , Iron
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/94753 , vital:31075
  • Description: The characteristic magnetic and spectroscopic features associated with the red monomeric or dimeric, and polymeric pyrazine-N-oxide (PyzNO) iron(II) perchlorate complexes; Fen(μ1,1-pyzNO)2n-2(pyzNO)3n+2(ClO4)2n (n = {1, 2}*, and the novel compound {Fe(μ-pyzNO-κN,κO)n-1(pyzNO-κN)2(pyzNO-κO)2}n(ClO4)2n†, respectively, were investigated. These properties are altered substantially when the complexes are hydrated; for instance, by atmospheric exposure. The resulting species; Fe(pyzNO)5(H2O)3(ClO4)2* and [Fe(pyzNO-κN)4(H2O)2](ClO4)2.2H2O†, which have different hues of a bright yellow colour, were found to exhibit strong paramagnetism, in contrast to their anhydrous precursors, which are ‘EPR silent’. A low spin → high spin crossover (LS→HS, SCO) transition was therefore proposed to occur as the complexes become hydrated by atmospheric moisture. The red→yellow colour change is reversible, and dehydration of the yellow species by heating regenerates the red variant, a feature which lends itself to the potential applicability of the system as a sensor. Further emphasis on this potential derives from the fact that the hydration/dehydration process, and its accompanying physical changes, appears reversible even after many such treatments. It became of interest, then, to determine if these changes were limited to water-exposed samples, or if they occurred under more diverse solvent atmospheres. The reversibility of such exposure on the structure of the novel polynuclear complex was therefore investigated. In general, it was found that there occurred a strong solvent-complex association for the more polar solvents. Red→yellow, LS→HS events were seen when the complex was exposed to the vapours of p-dioxane, acetaldehyde and formaldehyde, and to a lesser extent, to that of methanol. In each case, significant structural changes were seen, as evidenced be comparative XRPD and thermo-analytical studies. Some of these changes have however been ascribed to the effects of partial dissolution upon extended exposure of the complex to the associated media. Exposure to less polar solvent atmospheres, such as those of cyclohexane, toluene, diethyl ether, etc., showed some signs of mild solvent surface adhesion, but were unaccompanied by discernible magnetic and colour changes. Another novel complex was produced during attempts to synthesize the PyzNO complexes from a mixture of a 2,2’-dimethoxypropane (DMP) and ethanol (1:1, v/v), rather than the methanol/DMP mixture which had been alternately used. The formula of the resulting complex is Fe(pyzNO)6(ClO4)2.3EtOH*. This EPR inactive product was orange in colour, and transformed into a bright yellow, strongly paramagnetic species upon atmospheric exposure. Further solvent studies showed that this species interacted significantly with all solvents tested, but generally more strongly with increasing solvent polarity. Orange→yellow colour changes occurred in environments saturated with p-dioxane, acetaldehyde and formaldehyde vapours. The DMSO-exposed sample transformed to dark red, due to suspected PyzNO substitution by the solvent. The red→yellow and orange→yellow colour changes were ascribed to the formal substitution of O-coordinated PyzNO (μ-PyzNO in the polymeric complex) by the incoming solvent. The resulting structural and geometric changes stimulated a redistribution of d electrons among the new constituent molecular orbitals of altered energy and symmetry. Therefore, although the colour changes were not conventionally solvatochromic - in that the original structure was lost on exposure – data suggested that it was the coordination of species of higher donor strength that produced the observed bathochromic shifts. A novel 4,4’-bipyridine-N-oxide Fe(II) perchlorate complex, Fe2(bipyNO)5(ClO4)4.6MeOH†, was also produced, primarily for physicochemical comparison with the PyzNO complexes. No colour or magnetic changes were seen on atmospheric exposure. The original complex was observed to be inherently paramagnetic, and no SCO events occurred upon solvent exposure. Despite this, thermal analyses showed that the complex did exhibit the strong uptake of polar solvents in general, but particularly with acetaldehyde. Significant structural changes upon exposure were limited to surface phenomena, with the exception of the acetaldehyde-exposed sample.
  • Full Text:
  • 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

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