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Managing the corporate reputation of a transforming organisation: a study of multimedia University of Kenya

  • Authors: Mtange, Margaret Mulekani
  • Date: 2020
  • Subjects: Organizational change -- Management , Universities and colleges -- Kenya -- Sociological aspects -- Case studies , Universities and colleges -- Research -- Economic aspects -- Kenya -- Case studies
  • Language: English
  • Type: Thesis , Doctoral , DPhil
  • Identifier: http://hdl.handle.net/10948/50837 , vital:42873
  • Description: Universities, like other organisations, are challenged to manage corporate identity and reputation to maintain a competitive edge. Few studies in Africa focus on the impact of internal communication on corporate identity and reputation management during organisational transformation. Thus, this study interrogated how a transforming and complex university in Kenya managed the corporate identity, image and reputation for competitive advantage. The purpose of the study was to establish how Multimedia University of Kenya (MMU) management communicated with its employees to nurture the corporate identity, image and reputation during a ten-year period of transformation. The study draws insights from in-depth interviews with 23 university management members, 178 self-administered questionnaires through random stratification of MMU employees, and content review of two MMU strategic plans ranging from 2011 to 2021. The findings suggest that MMU management used formal and interactive channels to create awareness of organisational transformation. These channels included face-to-face engagements, formal meetings and mediated communication through telephone conversations and intranet that facilitated record keeping. The management engaged in top-down and bottom-up communication to build employee trust, while employees expressed reservations of bottom-up information accuracy, suggesting information exclusion. On the contrary, the employees preferred digital and interpersonal channels for internal communication, which included telephone conversations, social media, personal visits by MMU management, and university events. Publicity activities were to disseminate information to prospective students and sponsors through selected private television, vernacular radio, and MMU radio stations, traditional print media, and the MMU website to communicate the MMU brand and image. Employees acknowledged that MMU brands itself as a leader in telecommunication, technology, mechanical, manufacturing, and media training through state-of-the-art equipment, robust faculty, and problem-solving ventures through research. The current study proposes stronger employee involvement, executive packaging and positioning, coaching successful faculty members as brand ambassadors, retraining employees, and employee participation in policy formulation to enhance new culture. In addition, these opositions will enhance the corporate identity, brand, as well as university performance, product quality, policy and processes to enrich the corporate reputation during transformation. The findings challenge university management to actively engage the corporate communication function, emphasise employee participation, and focus on the continual improvement of corporate identity and reputation management practices for competitive advantage. The current study proposes a participative, multi-layered and multi-dimensional communication model for efficient and excellent internal communication. The current study recommends that corporate communication practitioner be strategically positioned to coordinate employee engagement, utilise appropriate communication channels and counsel university management on corporate identity, image and reputation management during organisational transformation.
  • Full Text:
  • Date Issued: 2020

Mechanism of action of non-synonymous single nucleotide variations associated with α-carbonic anhydrases II, IV and VIII

  • Authors: Sanyanga, T. Allan
  • Date: 2020
  • Subjects: Carbonic anhydrase , Carbonic anhydrase -- Therapeutic use , Nucleotides
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/167346 , vital:41470
  • Description: The carbonic anhydrase (CA) group of enzymes are Zinc (Zn2+) metalloproteins responsible for the reversible hydration of CO2 to bicarbonate (BCT or HCO− 3 ) and protons (H+) for the facilitation of acid-base balance and homeostasis within the body. Across all organisms, a minimum of six CA families exist, including, α (alpha), β (beta), γ (gamma), δ (delta), η (eta) and ζ (zeta). Some organisms can have more than one family, with exception to humans that contain the α family solely. The α-CA family comprises of 16 isoforms (CA-I to CA-XV) including the CA-VIII, CA-X and CA-XI acatalytic isoforms. Of the catalytic isoforms, CA-II and CA-IV possess one of the fastest rates of reaction, and any disturbances to the function of these enzymes results in CA deficiencies and undesirable phenotypes. CA-II deficiencies result in osteopetrosis with renal tubular acidosis and cerebral calcification, whereas CA-IV deficiencies result in retinitis pigmentosa 17 (RP17). Phenotypic effects generally manifest as a result of poor protein folding and function due to the presence of non-synonymous single nucleotide variations (nsSNVs). Even within the acatalytic isoforms such as CA-VIII that llosterically regulates the affinity of inositol triphosphate (IP3) for the IP3 receptor type 1 (ITPR1) and regulates calcium (Ca2+) signalling, the presence of SNVs also causes phenotypes cerebellar ataxia, mental retardation, and dysequilibrium syndrome 3 (CAMRQ3). Currently the majority of research into the CAs is focused on the inhibition of these proteins to achieve therapeutic effects in patients via the control of HCO− production or reabsorption as observed in glaucoma and diuretic medications. Little research has therefore been devoted into the identification of stabilising or activating compound that could rescue protein function in the case of deficiencies. The main aim of this research was to identify and characterise the effects of nsSNVs on the structure and function of CA-II, CA-IV and CA-VIII to set a foundation for rare disease studies into the CA group of proteins. Combined bioinformatics approaches divided into four main objectives were implemented. These included variant identification, sequence analysis and protein characterisation, force field (FF) parameter generation, molecular dynamics (MD) simulation and dynamic residue network analysis (DRN). Six variants for each of the CA-II, CA-IV and CA-VIII proteins with pathogenic annotations were identified from the HUMA and Ensembl databases. These included the pathogenic variants K18E, K18Q, H107Y, P236H, P236R and N252D for CA-II. CA-IV included the pathogenic R69H, R219C and R219S, and benign N86K, N177K and V234I variants. CA-VIII included pathogenic S100A, S100P, G162R and R237Q, and benign S100L and E109D variants. CA-II has been more extensively studied than CA-IV and CA-VIII, therefore residues essential to its function and stability are known. To discover important residues and regions within the CA-IV and CA-VIII proteins sequence and motif analysis was performed across the α-CA family, using CA-II as a reference. Sequence analysis identified multiple conserved residues between the two acatalytic CA-II and CA-IV, and the acatalytic CA-VIII isoforms that were proposed to be essential for protein stability. With exception to the benign N86K CA-IV variant, none of the other pathogenic or benign CA-II, CA-IV and CA-VIII SNVs were located at functionally or structurally important residues. Motif analysis identified 11 conserved and important motifs within the α-CA family. Several of the identified variants were located on these motifs including K18E, K18Q, H107Y and N252D (CA-II); N86K, R219C, R219S and V234I (CA-IV); and E109D, G162R and R237Q (CA-VIII). As there were no x-ray crystal structures of the variant proteins, homology modelling was performed to calculate the protein structures for characterisation. In CA-VIII, the substitution of Ser for Pro at position 100 (variant S100P) resulted in destruction of the β-sheet that the SNV was located on. Little is known about the mechanism of interaction between CA-VIII and ITPR1, and residues involved. SiteMap and CPORT were used to identify binding site amino for CA-VIII and results identified 38 potential residues. Traditional FFs are incapable of performing MD simulations of metalloproteins. The AMBER ff14SB FF was extended and Zn2+ FF parameters calculated to add support for metalloprotein MD simulations. In the protein, Zn2+ was noted to have a charge less than +1. Variant effects on protein structure were then investigated using MD simulations. Root mean square deviation (RMSD) and radius of gyration (Rg) results indicated subtle SNV effects to the variant global structure in CA-II and CA-IV. However, with regards to CA-VIII RMSD analysis highlighted that variant presence was associated with increases to the structural rigidity of the protein. Principal component analysis (PCA) in conjunction with free energy analysis was performed to observe variant effects on protein conformational sampling in 3D space. The binding of BCT to CA-II induced greater protein conformational sampling and was associated with higher free energy. In CA-IV and CA-VIII PCA analysis revealed key differences in the mechanism of action of pathogenic and benign SNVs. In CA-IV, wild-type (WT) and benign variant protein structures clustered into single low energy well hinting at the presence of more stable structures. Pathogenic variants were associated with higher free energy and proteins sampled more conformations without settling into a low energy well. PCA analysis of CA-VIII indicated the opposite to CA-IV. Pathogenic variants were clustered into low energy wells, while the WT and benign variants showed greater conformational sampling. Dynamic cross correlation (DCC) analysis was performed using the MD-TASK suite to determine variant effects on residue movement. CA-II WT protein revealed that BCT and CO2 were associated with anti-correlated and correlated residue movement, highlighting at opposite mechanisms. In CA-IV and CA-VIII variant presence resulted in a change to residue correlation compared to the WT proteins. DRN analysis was performed to investigate SNV effects of residue accessibility and communication. Results demonstrated that SNVs are associated with allosteric effects on the CA protein structures, and effects are located on the stability assisting residues of the aromatic clusters and the active site of the proteins. CA-II studies discovered that Glu117 is the most important residue for communication, and variant presence results in a decrease to the usage of the residue. This effect was greatest in the CA-II H107Y SNV, and suggests that variants could have an effect on Zn2+ dissociation from the active site. Decreases to the usage of Zn2+ coordinating residues were also noted. Where this occurred, compensatory increases to the usage of other primary and secondary coordination residues were observed, that could possibly assist with the maintenance of Zn2+ within the active site. The CA-IV variants R69H and R219C highlighted potentially similar pathogenic mechanisms, whereas N86K and N177K hinted at potentially similar benign mechanisms. Within CA-VIII, variant presence was associated with changes to the accessibility of the N-terminal binding site residues. The benign CA-VIII variants highlighted possible compensatory mechanisms, whereby as one group of N-terminal residues loses accessibility, there was an increase to the accessibility of other binding site residues to possibly balance the effect. Catalytically, the proton shuttle residue His64 in CA-II was found to occupy a novel conformation named the “faux in” that brought the imidazole group even closer to the Zn2+ compared to the “in” conformation. Overall, compared to traditional MD simulations the incorporation of DRN allowed more detailed investigations into the variant mechanisms of action. This highlights the importance of network analysis in the study of the effects of missense mutations on the structure and function of proteins. Investigations of diseases at the molecular level is essential in the identification of disease pathogenesis and assists with the development of specifically tailored and better treatment options especially in the cases of genetically associated rare diseases.
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  • Date Issued: 2020

Mechatronics based highspeed rotational piezo actuator

  • Authors: Raffler, Oliver
  • Date: 2020
  • Subjects: Piezoelectric materials , Piezoelectric devices Mechatronics
  • Language: English
  • Type: Thesis , Doctoral , DPhil
  • Identifier: http://hdl.handle.net/${Handle} , vital:39811
  • Description: The aim of this thesis is the development of a novel mechatronics-based high speed piezo actuator for rotational and linear motion. Mainly, the thesis deals with the development of a system for mechanical coupling of any number of piezostacks. This mechanical coupling allows the actuator to achieve a significantly increased deflection compared to current approaches. The developed concept offers the possibility of a linear or rotary motion. It is also possible to combine the two types of movement. In the first step, in order to gain a better understanding of the topic, the piezo technology and especially the existing piezo actuators and -motors are examined. Currently, the force generated by the piezo actuators is mainly transmitted by friction. The only exception is the PAD-Actuator, which transmits force by means of form locking. The concept developed here also transmits its force by means of form locking and, in addition to that, offers a novel and unique drive concept in the field of piezo actuators. In the course of this thesis a new concept for the mechanical coupling of piezo actuators was developed, simulated and subsequently manufactured. Thus the system could be examined under real conditions. The investigations carried out mainly dealt with quasi-static and dynamic investigations. In addition to that, the emission of the airborne and structure-borne noise of the system was analysed.
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  • Date Issued: 2020

Microbial fuel cells for remediation of metal rich wastewater coupled with bioelectricity generation

  • Authors: Mshoperi, Edith
  • Date: 2020
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/124112 , vital:35540
  • Description: Expected release date-April 2022
  • Full Text: false
  • Date Issued: 2020

Mineral Resources Governance and Socio-Economic Development in Zimbabwe

  • Authors: Chawatama, Chrispen Tauya
  • Date: 2020
  • Subjects: Mines and mineral resources -- Zimbabwe Mining law --Zimbabwe
  • Language: English
  • Type: Thesis , Doctoral , PhD(Dev)
  • Identifier: http://hdl.handle.net/${Handle} , vital:42996
  • Description: This study focused on investigating mineral resources governance (reflected in terms of three indicators of transparency, accountability and stakeholder inclusion) and its effect on socioeconomic development (in terms of three indicators of education, health and household incomes. Mineral resources can be a blessing and can lead to socioeconomic transformation of a country if they are managed transparently, accountably, inclusively equitably and sustainably. On the other hand, these subsoil capital assets can be a ‘curse’ and lead to poverty, conflicts amongst interest groups, elite capture, corruption and economic stagnation if they are not properly managed. Good governance of mineral resources seeks to ensure that the harnessing of mineral resources benefits the economy, enhances the quality of life and reduces poverty amongst citizens. The mining sector of Zimbabwe has risen to be the key economic sector in terms of its contribution to the GDP, FDI, fiscal revenue, exports and employment creation, particularly after the discovery of diamonds and more gold deposits in the country. However, in spite of the growth of the mining sector and its elevation to the mainstay of the economy, glaring dire socioeconomic conditions in terms of unemployment and high poverty levels, poor health, education and household incomes, leads one to question the way the country’s opulent mineral resources are being governed. The study used a mixed methods approach, through use of primary data (quantitative and qualitative data) and secondary data (archival data) as the basis for the collection as well as analysis of data. Complementarity of the research methods was achieved through use of data from household survey with 160 households in Mhondoro-Ngezi, Chegutu, Kwekwe and Shurugwi and in-depth interviews with officials of government ministries; of Finance and Economic Development, Health and Childcare, Primary and viii Secondary Education, local councillors, CSOs; ZELA and ZIMCODD, Traditional chiefs and ZASMC. The study established that mining growth is contributing somewhat to socio-economic development through employment creation, corporate social responsibility, CSOTs, ESPOs, taxation and royalties, but broad-based development has not taken place in the four districts. The study proposes a holistic mineral resources governance and socioeconomic development framework. The study recommends the Repeal of MMA and gazetting of a more comprehensive legal framework, implementation of constitutional provisions on transparency, accountability and stakeholder inclusion, adoption of free online tools for mineral processes disclosure, consolidation of the mining fiscal regime and so on.
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  • Date Issued: 2020

Modelling and investigating primary beam effects of reflector antenna arrays

  • Authors: Iheanetu, Kelachukwu
  • Date: 2020
  • Subjects: Antennas, Reflector , Radio telescopes , Astronomical instruments -- Calibration , Holography , Polynomials , Very large array telescopes -- South Africa , Astronomy -- Data processing , Primary beam effects , Jacobi-Bessel pattern , Cassbeam software , MeerKAT telescope
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/147425 , vital:38635
  • Description: Signals received by a radio telescope are always affected by propagation and instrumental effects. These effects need to be modelled and accounted for during the process of calibration. The primary beam (PB) of the antenna is one major instrumental effect that needs to be accounted for during calibration. Producing accurate models of the radio antenna PB is crucial, and many approaches (like electromagnetic and optical simulations) have been used to model it. The cos³ function, Jacobi-Bessel pattern, characteristic basis function patterns (CBFP) and Cassbeam software (which uses optical ray-tracing with antenna parameters) have also been used to model it. These models capture the basic PB effects. Real-life PB patterns differ from these models due to various subtle effects such as mechanical deformation and effects introduced into the PB due to standing waves that exist in reflector antennas. The actual patterns can be measured via a process called astro-holography (or holography), but this is subject to noise, radio frequency interference, and other measurement errors. In our approach, we use principal component analysis and Zernike polynomials to model the PBs of the Very Large Array (VLA) and the MeerKAT telescopes from their holography measured data. The models have reconstruction errors of less than 5% at a compression factor of approximately 98% for both arrays. We also present steps that can be used to generate accurate beam models for any telescope (independent of its design) based on holography measured data. Analysis of the VLA measured PBs revealed that the graph of the beam sizes (and centre offset positions) have a fast oscillating trend (superimposed on a slow trend) with frequency. This spectral behaviour we termed ripple or characteristic effects. Most existing PB models that are used in calibrating VLA data do not incorporate these direction dependent effects (DDEs). We investigate the impact of using PB models that ignore this DDE in continuum calibration and imaging via simulations. Our experiments show that, although these effects translate into less than 10% errors in source flux recovery, they do lead to 30% reduction in the dynamic range. To prepare data for Hi and radio halo (faint emissions) science analysis requires carrying out foreground subtraction of bright (continuum) sources. We investigate the impact of using beam models that ignore these ripple effects during continuum subtraction. These show that using PB models which completely ignore the ripple effects in continuum subtraction could translate to error of more to 30% in the recovered Hi spectral properties. This implies that science inferences drawn from the results for Hi studies could have errors of the same magnitude.
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  • Date Issued: 2020

Mothers’ perceptions of the effects of the babies in mind programme on maternal mental health and mother-infant attachment: a South African narrative study

  • Authors: Naicker, Samantha , Cronje, Johan
  • Date: 2020
  • Subjects: Mother and infant
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/46414 , vital:39590
  • Description: The focus of this study is on mothers, motherhood and the Babies in Mind programme as an early intervention strategy for mothers in South Africa. The rate of maternal mental ill health in our country is alarming. Research consistently confirms that maternal mental health directly affects infant and child mental health. One of the major determinants of mental health is mother-infant attachment. Studies have indicated the range of deleterious effects that maternal mental ill-health and mother-infant attachment issues have on offspring from infancy to adulthood. This has implications for the mental health of future generations and society at large. Researchers have called for evidence-based interventions that address maternal mental health and mother-infant attachment, especially in developing countries. South Africa has no national prevention or treatment programme to address these needs. This study investigated the Babies in Mind programme as an early intervention option to address the gap in promoting maternal mental health and mother-infant attachment. A social constructionist, narrative study was employed to meet the objectives of the study. The aim was to explore mothers’ perceptions of the impact of the Babies in Mind programme, with particular reference to their mental health and their relationships to their infants. Focus was placed on understanding the social constructions of motherhood at the community level and how these constructions were reconstructed through the programme. Purposive sampling was employed and focus groups were conducted to collect the relevant data. The data was analysed using thematic analysis. The findings indicated that mothers’ experiences of the Babies in Mind programme were positive and there were improvements in their mental health and relationships to their infants. A relationship model for mothers was developed based on the themes that emerged from the data analysis. A platform for continued support and discussion was organised via a social media (Whatsapp) support group. Twelve 7guidelines were suggested for the implementation of intervention programmes such as the Babies in Mind programme at the community level.
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  • Date Issued: 2020

Navigating Blackness in the African Diaspora

  • Authors: Yates, Sarah
  • Date: 2020
  • Subjects: Ellison, Ralph. Invisible man , Everett, Percival. Erasure , Wicomb, Zoe. Playing in the light , Bulawayo, NoViolet. We need new names , Africans in literature , Race in literature , African fiction (English) -- History and criticism
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/145720 , vital:38461
  • Description: This thesis offers a comparative reading of Ralph Ellison’s Invisible Man, Percival Everett’s Erasure, Zoë Wicomb’s Playing in the Light and NoViolet Bulawayo’s We Need New Names in order to explore the diversity of subjectivities included within the terms ‘African’ and ‘black’ and to argue for the necessity of renewed definitions of Africa(nness) and blackness which allow for diverse and fluid representations. The diverse historical and political contexts in which these novels are published, as well as the critical and theoretical discussions which surround them demonstrate an evolution in literary portrayals of identity politics. As the categories of race and nation become more fluid, so too do narrative forms. In particular, this thesis is interested in the textual strategies authors use to navigate the various ways in which depictions of blackness continue to be restricted by racism, stereotypes, and the dynamics of a global literary market. As portrayals and discussions of identity politics proliferate in popular culture, they become increasingly commodified, and therefore increasingly restricted by the market.
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  • Date Issued: 2020

Negotiating family planning messages among Malawian men: A case study of vasectomy messages aimed at men in the Dedza and Karonga districts of Malawi

  • Authors: Ntaba, Jolly Maxwell
  • Date: 2020
  • Subjects: Social marketing -- Malawi , Vasectomy -- Social aspects -- Malawi , Malawians -- Attitudes , Men -- Malawi -- Attitudes , Men -- Conduct of life -- Malawi , Men -- Sexual behavior -- Malawi , Masculinity -- Malawi , Reproductive health in mass media -- Malawi , Reproductive health services -- Malawi
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/167200 , vital:41446
  • Description: Since the 1990s, vasectomy, the principal non-barrier method of contraception offered to men, has been vigorously promoted in Malawi, as a safe, effective and inexpensive form of birth control. Despite this marketing, the method has been chosen by only an estimated 0.01% of men in Malawi. This compares to about 11% of contraceptive using Malawian women, who have opted for tubal ligation, a more expensive and hazardous surgical procedure. Previous studies into this low uptake of vasectomy among men in Malawi, and other studies that have explored why no African country currently has a vasectomy rate of more than 1% of men, implicate cultural beliefs and traditional social practices among the key barriers to the diffusion of this particular innovation i.e. this method of contraception. Campaigns share new information in the hope that they will shift their audiences’ knowledge, and lead to changes in attitudes and practices, including the uptake of vasectomy. Social Marketing campaigns, even when they set out to explicitly accommodate these beliefs and challenge particular practices in order to promote various methods of contraception, are often inadequately conceived and sometimes poorly executed. Drawing on well-established theoretical perspectives developed by Cultural Studies scholars, including Reception Analysis and Thematic Analysis, this study investigates how men in two purposively selected districts of Karonga and Dedza in Malawi, interpret Social Marketing messages encouraging them to undergo vasectomies. The study examines key media texts and the nature of the involvement of a group of peer educators, dubbed ‘male champions’ in a 2017-2018 campaign by one of the leading Malawian providers of family planning services, the NGO Banja La Mtsogolo (BLM), to promote vasectomy. This is a purely qualitative case study that seeks to understand why these often-well-resourced campaigns have so little impact on the behaviour change they hope to inspire. Through individual interviews with the campaign’s designers, implementers, peer educators, focus group discussions with the campaign’s audiences, a close reading of texts used in the campaign, and observation, this study explores the circuits of communication and culture, through mechanisms of resonance, disconnection and even cognitive dissonance between the ‘encoders’ of the family planning messages and the decoders i.e. the intended audiences of the campaign. The study argues that as a result of several ‘modernist’ assumptions and outlooks, the campaign was unable to fully grasp the complex and contextually nuanced socio-cultural practices that factor into consideration of the campaign’s messages and the non-adoption of the proposed vasectomy method. The study further reveals, as many other studies have also observed, that the interpretation of the text promoting vasectomy is a complex process that is significantly shaped by the worldviews and lived experiences of the audiences. These views, as this study explores, are often complex and contradictory, interfacing aspirations of modernity with deeply held ‘traditional’ beliefs and practices. Although the campaigns are effective at transferring knowledge – it finds most targeted men have a relatively good understanding of the method and its efficacy – their prevailing socio-cultural attitudes and dispositions provide a strong countervailing discourse to the preferred reading of the campaign messages. This discourse exhorts having children, or the capacity to have children, even after a man has had several before, in current or previous marriages, or even in old age, as desirable and ‘rational’. The study therefore proposes, arising out of this detailed ethnographic research, a revised approach that argues that several social and cultural ‘vectors’ or ‘spheres of influence' need to be considered in new ways, in order to develop meaningful interventions in the promotion of vasectomy. This includes specific strategies to understand and challenge: 1. The enduring power of social stigma and scorn, and the notion of social shame. 2. The deep interplay between fertility and having children to notions of marriage, even in second or third marriages, and the interplay with perceptions of economic ‘value’ of children in the domestic political economy of marriage. 3. The embedded nature of provable fertility to notions of manhood. 4. The complex and nuanced involvement, at many levels, of broader social/family structures/personages in ‘personal’ decisions. 5. Forms of ‘hyperbolic discounting’, i.e. the calculating of precarious futures in various scenarios and its impact on current shorter-term calculations and gratifications. 6. Unusually high rates of infidelity in marriage, and seemingly low levels of trust in many partnerships. 7. The key role of interpersonal communication, i.e. the face-to-face elements of what are usually media-centric Social Marketing campaigns. The study recommends a more layered and nuanced approach to the promotion of vasectomy, propelled by a deeper understanding of these kinds of contexts and the interpretive power of the intended audience, as well as more nuanced segmentation of audiences, and more judicious use of peer-educators to support and deepen the mass media components of these communication campaigns.
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  • Date Issued: 2020

NFComms: A synchronous communication framework for the CPU-NFP heterogeneous system

  • Authors: Pennefather, Sean
  • Date: 2020
  • Subjects: Network processors , Computer programming , Parallel processing (Electronic computers) , Netronome
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/144181 , vital:38318
  • Description: This work explores the viability of using a Network Flow Processor (NFP), developed by Netronome, as a coprocessor for the construction of a CPU-NFP heterogeneous platform in the domain of general processing. When considering heterogeneous platforms involving architectures like the NFP, the communication framework provided is typically represented as virtual network interfaces and is thus not suitable for generic communication. To enable a CPU-NFP heterogeneous platform for use in the domain of general computing, a suitable generic communication framework is required. A feasibility study for a suitable communication medium between the two candidate architectures showed that a generic framework that conforms to the mechanisms dictated by Communicating Sequential Processes is achievable. The resulting NFComms framework, which facilitates inter- and intra-architecture communication through the use of synchronous message passing, supports up to 16 unidirectional channels and includes queuing mechanisms for transparently supporting concurrent streams exceeding the channel count. The framework has a minimum latency of between 15.5 μs and 18 μs per synchronous transaction and can sustain a peak throughput of up to 30 Gbit/s. The framework also supports a runtime for interacting with the Go programming language, allowing user-space processes to subscribe channels to the framework for interacting with processes executing on the NFP. The viability of utilising a heterogeneous CPU-NFP system for use in the domain of general and network computing was explored by introducing a set of problems or applications spanning general computing, and network processing. These were implemented on the heterogeneous architecture and benchmarked against equivalent CPU-only and CPU/GPU solutions. The results recorded were used to form an opinion on the viability of using an NFP for general processing. It is the author’s opinion that, beyond very specific use cases, it appears that the NFP-400 is not currently a viable solution as a coprocessor in the field of general computing. This does not mean that the proposed framework or the concept of a heterogeneous CPU-NFP system should be discarded as such a system does have acceptable use in the fields of network and stream processing. Additionally, when comparing the recorded limitations to those seen during the early stages of general purpose GPU development, it is clear that general processing on the NFP is currently in a similar state.
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  • Date Issued: 2020

Non-marital fertility in South Africa: trends, determinants and implications

  • Authors: Kara, Reesha
  • Date: 2020
  • Subjects: Fertility, Human -- South Africa , Child rearing -- South Africa , Parenting -- South Africa , Motherhood -- South Africa
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/165620 , vital:41264
  • Description: Background: Non-martial fertility is traditionally associated with teenage pregnancy however international and South African literature has detailed increases in the number of adult women who are having children outside of a marriage. South African literature on non-marital fertility is sparse as it lacks a national overview of the trends and determinants of non-marital fertility among women aged 30 and older. The aim of this study was to present a national overview of non-marital fertility among women aged 30 and older. South African’s attitudes to and opinions of non-marital fertility were also investigated, and the lived realities of older mothers were explored. Methods: A mixed-methods research design was employed where the General Household Survey, National Income Dynamics Study and the South African Social Attitudes Survey were the main data sources. Using these data sets, descriptive and inferential statistics were computed using Stata. Using purposive and snowball sampling, four never-married older mothers (NMOMs) from KwaZulu-Natal (Durban) were identified as research participants. The in-depth life histories of these women were collected through face-to- face semi-structured interviews. Results: The results show an 18.43% increase in never-married mothers aged 15- 49 between 2002 and 2017 and interestingly, this increase is not necessarily driven by older mothers (30-49). NMOMs belonged to households with a lower average per capita total monthly household income (R1873.91) compared to all mothers aged 30-49 (R3428.76). NMOMs were also more likely to live in female-headed households (89.52%), to be household heads (64.22%) and to live in traditional areas (35.72%). Between 2002 and 2017, there was a 76.76% increase in mothers (aged 30-49) who were never married and a 7.74% decrease in those who were married, indicating a change in the marital profile of mothers. Despite this national increase in non-marital fertility, South African’s believe that premarital sexual activity is wrong, and that childbearing should take place within a marriage. Similar sentiments were echoed in the in-depth life histories as being the sole breadwinner and primary caregiver, the research participants experienced challenges as single mothers. Conclusion and recommendations: The study has found that there has been an increase in non-marital fertility in South Africa between 2002 and 2017 and that there is an economic element to non-marital fertility in the country. Additional research into non-marital fertility at a national level is recommended with a focus on all women aged 15-49.
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  • Date Issued: 2020

Not Yet Uhuru! Attuning to, re-imagining and regenerating transgressive decolonial pedagogical praxis across times Khapa(ring) the rising cultures of change drivers in contemporary South Africa

  • Authors: Kulundu-Bolus, Injairu
  • Date: 2020
  • Subjects: Not Yet Uhuru (Arts Project) , Anti-imperialist movements -- South Africa , Education -- Social aspects -- South Africa , Social change -- South Africa , Education -- Philosophy -- South Africa , Arts and society -- South Africa
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/166081 , vital:41327 , 10.21504/10962/166081
  • Description: The “Not yet Uhuru!” project positions itself as emancipatory African research in motion. It is a regenerative project that responds to the concern that whilst dominant discourses can articulate what African states, societies and economies are not, we still know very little about what they actually are. This is a particularly important gap in how research on Africa is conceptualised, especially as it pertains to apprehending the futures that the majority of young people on the continent are instinctively leading themselves to (Mbembe, 2001, p.9). The project seeks to forgo youth development strategies that act as a form of containment by prescribing normative aspects of citizenship on young leaders in ways that stifle the transgressive impulses they have reason to value (Kelley in Tuck and Yang, 2014, p.89). The study traces rising cultures in transgressive decolonial pedagogical praxis across times, as a way of “khapa(ring)” or accompanying the contemporary questions that Change Drivers in South Africa hold at the edge of their praxis. The study co-conspired with 21 Change Drivers in South Africa who were interested in regenerating and re-imagining what transgressive decolonial praxis could be in these times based on their experiences and learnings. Residential art-based workshops that explored each co-conspirator’s offerings on the subject were distilled through the medium of film. These in turn were analysed using an “ethics of attunement” that produced songs as a reflexive pedagogical tool (Lispari, 2014, p.176). Sharing the resonate echoes of their praxis through song created another iterative reflection on their praxis two years after their initial offerings. As a way of weaving together the findings with a historical perspective, the resonant praxis of Change Drivers was put into conversation with three unconventional reviews that trace impulses around transgressive decolonial pedagogical praxis through fictional texts, political theory, poetry and intergenerational analysis, in order to surface resonant themes in praxis that echo across different times in history. This methodology sought to engage the question of the archive in pluriversal ways that appealed to different sensibilities, including the imaginative and hermeneutical, the traditionally analytical as well as the gifts of the lyrical and the erotic as different conceptual threads needed to resource the study. The reviews additionally spanned periods in the history of the continent that hold questions around precolonial and nascent colonial encounters, efforts to transgress within the liberatory movements and the intergenerational transmissions embedded in women and queer people’s struggles. The themes that coalesced across times were leveraged into capsules of rising cultures that form an experimental nexus for the practice of transgressive decolonial pedagogical praxis that is already underway. These rising cultures were conceptualised as meditations on what it means to live into a vision of home built on the explorations of a paradigm of peace, humanness, pluriversality and decolonial love for those like and unlike us that strive for freedom on this continent (Dlala, 2017, p.52; Ndlovu- Gatsheni, 2013, p.142; Gqola, 2017, pp.197, 199). The rising ultures were reconciled through the creation of a litany that chronicles different refrains in transgressive decolonial pedagogical praxis in contemporary times. The litany is a tool that charts particular experiences that are surfacing as symptomatic. It seeks to generously surface the contradictions that we are collectively starting to see past, whilst acknowledging the tensions that we need to straddle, integrate and navigate towards greater synthesis. The litany is an honest way of acknowledging the glimpses gained of who we are in this present moment, while we continually challenge ourselves to open up to questions about what it means to grapple towards decolonial futures. This stance has influenced my role as an educator to unconditionally embrace movements that already underway, and reflect these back to those that I am conspiring with in ways that promote an ethic of care, solidarity and critical engagement. The study celebrates what is possible when we do not theorise ourselves away from the questions embedded in our current praxis. This is an ethic that chooses to stay close to the phenomena arriving at present, whilst acknowledging the historical experiences that echo it as a collective pulse for meaningful experimentation and praxis. The study believes by being faithful to ways of amplifying, integrating and reflecting what has been emerging for us over time, we build our capacity to better respond with an ethic centred on transgressive decolonial pedagogical praxis. This is the kind of accompaniment and care that Change Drivers across the continent deserve as they make the way towards a future worthy of their longing (Rushdie, 1999).
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  • Date Issued: 2020

Ocean dynamics of the shelf and bays of the eastern Agulhas bank: a process-oriented numerical modelling study

  • Authors: Bailey, Dylan Francis
  • Date: 2020
  • Subjects: Oceanography -- Research , Marine biology , Marine meteorology , Hydrography
  • Language: English
  • Type: Thesis , Doctoral , DPhil
  • Identifier: http://hdl.handle.net/10948/49038 , vital:41595
  • Description: There is a general need for a broader base of information on the finer detail of ocean processes in the Eastern Agulhas Bank region. In this thesis, the Regional Ocean Modelling System (ROMS) was applied to resolve high resolution (~1km) bay and shelf scale ocean processes along the south eastern coastline of South Africa using an offline multi-nested approach. Experimental and reference ocean model runs were used with in situ instrument mooring data to investigate how currents and temperature in the bays and the adjacent shelf are affected by the bathymetry, Agulhas Current (AC), regional winds, and coastal trapped waves (CTW). Focus was given to temperature, circulation, and coastal trapped waves, given the abundance of hourly in situ mooring data for these variables, making them suitable for comparison with the ocean model. SST variability trends were seasonally and spatially predictable, being greatest in the summer months and smallest in the winter months. A region of high SST variability extended from Port Alfred toward the south-west, indicating entrainment of nearshore upwelled water and instabilities in the inshore front of the AC. Shelf bottom temperature variability had a more spatially diverse seasonal trend, with coastal variability the highest (lowest) and offshore variability the lowest (highest) during the summer (winter) months. A distinct asymmetry in mean seasonal shelf bottom temperatures evident to the south of Algoa Bay and St Francis Bay was shown to be dependent on the profile of the shelf margin in relation to the inshore front of the AC using an experimental model run. Bay-scale anti-cyclonic circulation patterns dominate the bays throughout the year, with regions of strong mean surface currents occurring south of Cape Recife and Cape St Francis. General circulation patterns over the shelf are strongly governed by regional wind regimes, with the strongest flows being south-westward occurring during north-easterly wind events. Shelf bottom flows typically follow the expected Ekman-veering response, apart from near coastal flows that are topographically steered. A region of consistently strong south-westward shelf bottom flow extends from the east of Port Alfred to the shelf margin south of Bird Island. This flow is predominantly driven by the AC, although its velocity is strongly governed by regional winds. Circulation patterns during powerful eastward moving wind systems are strongly governed by the passage of associated CTW. Comparisons with an experimental model run where surface winds were removed revealed that the shelf wave was responsible for 61% of water volume displacement during a CTW event, and that the coastal shear turbulence caused by this displacement has a direct effect on the mixed layer depth. The links made between the complex shelf and bay ocean processes indicate that subtle changes to the ocean state will have far reaching effects on the regional ocean environment and its biota. Given the challenges of climate change, this is of paramount importance if we are to quantify these effects and mitigate their impacts, particularly with respect to the socio-economic dependency of those who rely on the ocean for its living resources.
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  • Date Issued: 2020

On locating the experiences of second year science students from rural areas in Higher Education in the field of science: lived rural experiences

  • Authors: Madondo, Nkosinathi Emmanuel
  • Date: 2020
  • Subjects: Science students -- South Africa , Rural college students -- South Africa , Science -- Study and teaching (Higher) -- South Africa , Curriculum change -- South Africa , Learning -- Evaluation , Social justice and education -- South Africa , Action research in education -- South Africa , Participant observation -- South Africa , Critical realism , Ethnoscience -- South Africa , Focus groups -- South Africa , Bernstein, Basil
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/145758 , vital:38464
  • Description: This study was designed to investigate the experiences of Second Year Science students who come from rural backgrounds within a Higher Education context. The purpose of the study was to understand the enabling and/or constraining factors that influence the teaching and learning of Second Year Science students who come from rural contexts. Given this purpose, the participants that were considered relevant to answer the question: What are the enabling and constraining factors that influence teaching and learning of second year Science students who come from rural backgrounds at a South African University? were students from rural areas enrolled in the Faculty of Science at the research site, academic teachers and senior leaders’, and roles in providing enabling and/or constraining teaching and learning environment. The phenomenon under investigation was thus, the extent to which the teaching and learning environment, in the field of science, enable or constrain access to the Discourse of science for students who come from rural areas. To generate data, the study used focus group discussions, Participatory Learning and Action (PLA) tools as part of Participatory Action Research (PAR), digital documentaries, as well as academic teachers’ rich descriptions of the rationale for the design and delivery techniques of their modules by means of focus group interviews, as well as curriculum review documents. The purpose of Action Research (AR) in this study was to enable change by way of advancing a self-consciousness, envisaged to yield some action based on the enablements or constraints identified by the participants involved. Archer’s (1995, 1996) analytical dualism was used as the analytical framework to identify the interplay of structural, cultural and agential mechanisms shaping the emergence of, and practices associated with students’ experiences of the science curriculum and academic teachers’ observations of these experiences. Bernstein’s pedagogic device was also used to explain the options that academic teachers have to shape the curriculum, a curriculum that would reflect the experiences of the heterogeneity of the student cohort when designing their course guides, for example. The analysis thus used Archer’s (1995, 1996) Morphogenesis/Morphostasis framework through which change or non-change can be observed over time. The work of Bhaskar (1975, 1979) was important in this regard because it allows us to separate what we see, experience and understand (in the transitive world) from what is independent of our thoughts and experiences (the intransitive world) when conducting scientific enquiry, so that we are able to deduce the ‘real’ factors that enable and constrain the events and experiences being studied. Since there are multiple mechanisms operative that can act to include or exclude students in Science classrooms, particularly those who come from lower class, including those who come from rural areas, this study focuses on curriculum as one mechanism that can be at play in the problem of exclusion. In this study, I argue, the University and its structures like curriculum are not neutral but are historical, cultural, political and social, which is why persistent apartheid legacy and coloniality were seen as playing a role in how the curriculum is designed and thus enacted. This is the reason, a decolonial gaze was adopted in order to engage with social justice issues and in the process tease out the social relations of knowledge practices. A decolonial gaze provided a way to re-describe the structuring of the curriculum and the contradictions it sets up for black students, particularly those who come from lower class backgrounds, including those from rural areas. Findings reveal that the way in which the science curriculum (and/or teaching and learning) is structured, and thus enacted, tends to favour certain worldviews to the exclusion of others. Also, findings show that when students are presented with knowledge that seems completely separate from them, their identities, their heritage, their backgrounds and value systems, accessing that knowledge can seem inordinately difficult. Consequently, students from rural contexts are often alienated, because the “world” they bring and know is often not considered part of the starting point, neither is it seen as relevant when teaching the science curriculum. There is therefore a clear need to bring something ‘from home’ into our teaching as a means of reassuring students that all is not foreign and that what they already know is valuable.
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  • Date Issued: 2020

Passphrase and keystroke dynamics authentication: security and usability

  • Authors: Bhana, Bhaveer
  • Date: 2020
  • Subjects: Computer security -- Management , Computers -- Access control -- Codewords , Computers -- Access control -- Keystroke timing authentication , Entropy (Information theory)
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/146663 , vital:38546
  • Description: It was found that employees spend a total 2.25 days within a 60 day period on password related activities. Another study found that over 85 days an average user will create 25 accounts with an average of 6.5 unique passwords. These numbers are expected to increase over time as more systems become available. In addition, the use of 6.5 unique passwords highlight that passwords are being reused which creates security concerns as multiple systems will be accessible by an unauthorised party if one of these passwords is leaked. Current user authentication solutions either increase security or usability. When security increases, usability decreases, or vice versa. To add to this, stringent security protocols encourage unsecure behaviours by the user such as writing the password down on a piece of paper to remember it. It was found that passphrases require less cognitive effort than passwords and because passphrases are stronger than passwords, they don’t need to be changed as frequently as passwords. This study aimed to assess a two-tier user authentication solution that increases security and usability. The proposed solution uses passphrases in conjunction with keystroke dynamics to address this research problem. The design science research approach was used to guide this study. The study’s theoretical foundation includes three theories. The Shannon entropy formula was used to calculate the strength of passwords, passphrases and keystroke dynamics. The chunking theory assisted in assessing password and passphrase memorisation issues and the keystroke-level model was used to assess password and passphrase typing issues. Two primary data collection methods were used to evaluate the findings and to ensure that gaps in the research were filled. A login assessment experiment collected data on user authentication and user-system interaction for passwords and passphrases. Plus, an expert review was conducted to verify findings and assess the research artefact in the form of a model. The model can be used to assist with the implementation of a two-tier user authentication solution which involves passphrases and keystroke dynamics. There are a number of components that need to be considered to realise the benefits of this solution and ensure successful implementation.
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  • Date Issued: 2020

Patterns and Pattern Languages for Mobile Augmented Reality

  • Authors: Munro, Donald
  • Date: 2020
  • Subjects: Augmented reality , Educational technology
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/48510 , vital:40883
  • Description: Mixed Reality is a relatively new field in computer science which uses technology as a medium to provide modified or enhanced views of reality or to virtually generate a new reality. Augmented Reality is a branch of Mixed Reality which blends the real-world as viewed through a computer interface with virtual objects generated by a computer. The 21st century commodification of mobile devices with multi-core Central Processing Units, Graphics Processing Units, high definition displays and multiple sensors controlled by capable Operating Systems such as Android and iOS means that Mobile Augmented Reality applications have become increasingly feasible. Mobile Augmented Reality is a multi-disciplinary field requiring a synthesis of many technologies such as computer graphics, computer vision, machine learning and mobile device programming while also requiring theoretical knowledge of diverse fields such as Linear Algebra, Projective and Differential Geometry, Probability and Optimisation. This multi-disciplinary nature has led to a fragmentation of knowledge into various specialisations, making it difficult to integrate different solution components into a coherent architecture. Software design patterns provide a solution space of tried and tested best practices for a specified problem within a given context. The solution space is non-prescriptive and is described in terms of relationships between roles that can be assigned to software components. Architectural patterns are used to specify high level designs of complete systems, as opposed to domain or tactical level patterns that address specific lower level problem areas. Pattern Languages comprise multiple software patterns combining in multiple possible sequences to form a language with the individual patterns forming the language vocabulary while the valid sequences through the patterns define the grammar. Pattern Languages provide flexible generalised solutions within a particular domain that can be customised to solve problems of differing characteristics and levels of iii complexity within the domain. The specification of one or more Pattern Languages tailored to the Mobile Augmented Reality domain can therefore provide a generalised guide for the design and architecture of Mobile Augmented Reality applications from an architectural level down to the ”nuts-and-bolts” implementation level. While there is a large body of research into the technical specialisations pertaining to Mobile Augmented Reality, there is a dearth of up-to-date literature covering Mobile Augmented Reality design. This thesis fills this vacuum by: 1. Providing architectural patterns that provide the spine on which the design of Mobile Augmented Reality artefacts can be based; 2. Documenting existing patterns within the context of Mobile Augmented Reality; 3. Identifying new patterns specific to Mobile Augmented Reality; and 4. Combining the patterns into Pattern Languages for Detection & Tracking, Rendering & Interaction and Data Access for Mobile Augmented Reality. The resulting Pattern Languages support design at multiple levels of complexity from an object-oriented framework down to specific one-off Augmented Reality applications. The practical contribution of this thesis is the specification of architectural patterns and Pattern Language that provide a unified design approach for both the overall architecture and the detailed design of Mobile Augmented Reality artefacts. The theoretical contribution is a design theory for Mobile Augmented Reality gleaned from the extraction of patterns and creation of a pattern language or languages.
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  • Date Issued: 2020

Performance, functionalism and form in Ịzọn oral poety

  • Authors: Armstrong, Imomotimi
  • Date: 2020
  • Subjects: Ijo (African people , Ijo language , Folk poetry, Ijo , Folk poetry -- Nigeria
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/140641 , vital:37906
  • Description: Since the publication of Ruth Finnegan’s influential Oral Literature in Africa, way back in 1970, scholars have been paying earnest attention to oral traditions on the African continent. That seminal book pointed out to Africanist scholars the need to urgently collect and document the oral literatures of their various ethnic groups before they die out. However, it is the verbal arts of the major ethnic groups on the continent that very often benefit from this collection and documentation, as it were. Therefore, this study sought to examine the oral poetry of the Ịzọn, a minority ethnic nationality, located in the oil-rich Niger Delta region of Nigeria. The study employed unstructured interviews and participant observations to collect the data for the research. The transcribed and translated data was examined through three eclectic theories to the study of folklore: Russian formalism, performance and functionalism. The study found out that Ịzọn oral poetry is a combination of songs and one person’s praise chants. Moreover, it revealed that praise chanting is a recent practice amongst the Ịzọn that was introduced into Ịzọnland by Chief Adolphus Munamuna from the Yoruba of southwestern Nigeria. Furthermore, the study established that oral poetry plays important roles amongst the people. Besides, it ascertained that the performance of some sub-categories of the poetry is highly dramatic and theatrical. It also discovered that stylistic techniques such as formula, parallelism, proverb, ideophone, praise title, metaphor, repetition, alliteration, assonance, vowel lengthening, amongst others, give the poetry the quality of “literariness.” In addition, the study found out that the poetry, like oral poetry in other ethnic groups, demonstrates the three qualities of change, adaptability and survival. The study has contributed to existing scholarship on African oral traditions in the sense of collecting, documenting and generating awareness on Ịzọn oral poetry, most importantly pointing out the existence of praise chanting amongst a people who had no such culture and the conditions that gave rise to that practice.
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  • Date Issued: 2020

Phytoplankton of the Southern Agulhas Large Marine Ecosystem (sACLME)

  • Authors: Sonnekus, Martinus Jakobus
  • Date: 2020
  • Subjects: Botanical chemistry
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/47646 , vital:40261
  • Description: The southern Agulhas Large Marine Ecosystem (sACLME) consists of the greater Agulhas Current system, including the areas influenced by the Agulhas Current, the Agulhas Shelf, Agulhas Bank, Agulhas Retroflection as well as the Agulhas Return Current. Four biogeographical regions were identified within the sACLME and the composition of the phytoplankton communities and the associated physico-chemical variables in each were investigated. Water temperature and nitrate concentration were found to be the main drivers of the sACLME phytoplankton community. A total of 215 phytoplankton taxa were identified that were separated into two groups: the Agulhas Current group and the Southwest Indian Ocean Ridge group. The structure of the phytoplankton community was consistently homogeneous throughout the sACLME. Nutrient concentrations of the water varied, but nitrate was the most abundant source of nitrogen, especially in regions that were subjected to the upwelling of cold nutrient-rich water. The phytoplankton communities were significantly influenced by the availability and stoichiometry of the macronutrients nitrogen; phosphorus and silicon. The low mean N:P ratio of 5.5 is an indication that the waters of the sACLME are generally nitrogen limited, as is typical of oceanic systems. There is a change in phytoplankton cell size and functional groups within in the various water masses that are specific to certain biogeographical regions within the Agulhas Current system. It is clear that frontal systems may form barriers between phytoplankton communities.
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  • Date Issued: 2020

Plankton dynamics in response to algal blooms in a highly eutrophic estuary in South Africa

  • Authors: Smit, Taryn
  • Date: 2020
  • Subjects: Algal blooms -- South Africa , Estuaries -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , DPhil
  • Identifier: http://hdl.handle.net/10948/49303 , vital:41619
  • Description: The global rise in the incidence of harmful algal blooms in estuaries is a major concern given their importance as a nursery area for a variety of invertebrates and fishes. On the warm-temperate, south-east coast of South Africa, the Sundays Estuary experiences persistent, seasonal HABs due to stable eutrophic conditions. Spring blooms of the dinoflagellate, Heterosigma akashiwo, were recorded for several years in the estuary. This Raphidophyte is known for its consequences in fish and shellfish aquaculture and exhibits harmful properties such as mucilage and reactive oxygen species production. Subsequently, the dissertation investigated larval fish assemblage dynamics, larval prey and predator dynamics and body condition in association with H. akashiwo blooms. HABs mainly altered the water quality within the mesohaline zone in terms of microalgal biomass and dissolved oxygen. Hypereutrophic blooms of H. akashiwo reached 24 996 cells∙mL-1 during the study period. Supersaturated dissolved oxygen concentrations (up to ~13 mg∙L-1 at night and ~21 mg∙L-1 during the day) were recorded during hypereutrophic blooms (> 80 μg∙L-1, ≥ 2781 H. akashiwo cells∙mL-1). Dissolved oxygen differed significantly by bloom state, with the highest dissolved oxygen concentrations. Larval fish density, diversity and community structure variability were lower during hypereutrophic blooms compared to standard blooms and bloom absence, albeit statistically insignificant. Estuarine resident larval density was negatively correlated with dissolved oxygen concentration (P < 0.001). Dominant prey copepod of G. aestuaria larvae, P. hessei, was less abundant and variable during hypereutrophic blooms (mean: 664, range: 4-4301 individuals per m3) compared to standard blooms (mean: 950, range: 2-5237 individuals per m3) and bloom absence (mean: 1182, range: 23-7259 individuals per m3). Although HABs did not appear to drive a mismatch between prey and G. aestuaria larvae, early juvenile larvae made only a small contribution to the assemblage (0.2-1.8%). In terms of predator effects, yolk sac larvae were negatively related to R. terranatalis (P < 0.05). A significant positive relationship was found between prey, P. hessei and G. aestuaria preflexion (P < 0.001), flexion (P < 0.001) and postflexion (P < 0.05) larvae. In a world first, the effects of HABs were investigated on a larval fish species, Gilchristella aestuaria, using biochemical body condition analyses. During severe bloom conditions, G. aestuaria larvae were smaller and the assemblage consisted of mainly early developmental stages (stats). Body condition (RNA per dry weight) was poorest in the presence of hypereutrophic blooms (P < 0.001). A bell-curved relationship between RNA/DW and dissolved oxygen concentration was also produced in a 3-day time-lagged GAM (P < 0.001). In conclusion, hypereutrophic bloom conditions appeared to trigger adult G. aestuaria spawning in the upper mesohaline zone of the estuary in response to heightened primary productivity which occurs during the early bloom stage. However, reductions in copepod abundance (P. hessei) and unfavourable oxygen concentrations interfered with grow-out of G. aestuaria larvae. This research showed that HABs can alter nursery properties to the detriment of G. aestuaria larvae can have serious knock-on effects up the food chain. The loss in abundance of adult, juvenile and larval G. aestuaria, a key forage fish in South African estuaries, has major implications for estuarine food webs, especially in reduced prey availability to juvenile fishes and birds. There is still much to learn about the effects of HABs on the physiological and behavioural aspects on plankton communities worldwide.
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  • Date Issued: 2020

Planning considerations for smart meter implementations in South Africa

  • Authors: Muchenje, Tonderai
  • Date: 2020
  • Subjects: Application software -- Development , Smart power grids
  • Language: English
  • Type: Thesis , Doctoral , DPhil
  • Identifier: http://hdl.handle.net/10948/46218 , vital:39515
  • Description: Smart meter implementations are still in their infancy in many African countries. This is evident by the lack of research on the subject in the African context. Most of the research studies are either Eurocentric or US-centric. Although these studies are important and informative, they might not address the African challenges in context. Hence, South Africa was chosen as the testbed for an investigation that addresses the apparent knowledge gap. This study set out to formulate a framework for planning considerations in the implementation of smart meter technology within South Africa. Through extensive literature review and analysis, the technology acceptance model (TAM) was chosen as a foundational framework for this study. Although TAM is widely used for researching technology acceptance and use, its applicability was found to be inadequate in explaining customer centric factors in smart metering. Therefore, it was supplemented with factors from the theory of reasoned action (TRA), the theory of planned behavior (TPB), privacy calculus theory (PCT), as well as the unified theory of acceptance and use of technology (UTAUT). A total of 11 consumer-centric factors were identified, and these were statistically analysed using the structural equation modelling technique (SEM). Ten (10) consumer-centric factors was found to be significant. These were attitude, perceived value, monetary cost, privacy risk, perceived ease of use, perceived usefulness, facilitating conditions, social norms, trust in technology and behavioral intention. Hypothesis testing confirmed that, not one acceptance model could adequately be used to identify and explain the consumer-centric factors that can be incorporated for planning considerations for smart meter implementation in South Africa. It was further observed that the consumer-centric factors such as environmental issues, security, reliability and health issues that were important in developed countries were not deemed so in South Africa. From a methodological perspective, the study attests to contextual localised application as opposed to universal meaning and measurement invariance when incorporating planning consideration for smart meter implementation in South Africa as compared to European countries and the United States of America. Finally, the findings hold some practical implications, as they showed the practical utility of the model in predicting the consumer-centric factors that can be incorporated for planning considerations. In support, the Business Model Canvas (BMC) was found to be a useful tool in deriving and reporting on the formulation of planning consideration guidelines. Using the BMC, five planning consideration guidelines were derived: customer segmentation, partnerships, benefits communication, value identification and customer attitude. These planning considerations will allow smart meter providers to identify their customers, partners and value propositions they might need to offer consumers to facilitate a higher smart meter acceptance and use. The proposed planning consideration guidelines can practically be used by policymakers and regulators for several aspects for future pervasive technology acceptance studies. This research has, therefore, created a platform for further research in the smart technology domain while providing a usable predictive framework for the identification of consumer-centric factors and formulation of planning considerations guidelines for smart meter implementation within the South African context.
  • Full Text:
  • Date Issued: 2020
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