Theses and Dissertations (University of Pretoria)

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Understanding the influence of entrepreneurial failure on the relationship between the serial entrepreneur and the church as a community of interest
Zulch, Hermanus Barend (University of Pretoria, 2025)
The extant literature on entrepreneurial failure indicates that such failure is far more widespread than reported and affects the relationship with the community of interest. It is therefore crucial to understand how entrepreneurial failure influences the relationship to assist the entrepreneur in recovering and assess the role the community of interest plays in the process. However, the literature on entrepreneurial failure is unclear about how the relationship will be affected. Therefore, this research was designed to expand the theory on entrepreneurial failure by understanding how the relationship is influenced. The study used the entrepreneurial failure literature to formulate the research question, “How does entrepreneurial failure influence the relationship between the serial entrepreneur and the church as a community of interest?” Prior research had identified the Christian church as a community of interest. Through the affiliation of its members, the Christian church represents a significant part of the South African economic community; thus, its effect on the economic community is substantial. For this research, nine churches were selected as cases. In total, 35 interviews were conducted with church representatives and entrepreneurs, yielding seven identified themes. The study determined that the relationship between the failed entrepreneurs and the church was influenced, but the level of influence depended on several factors. The most significant factor was that the relationship between the church and the entrepreneur before the business failure directly affected the entrepreneurs’ actions, and how they managed the relationship and the cost of failure. However, the church was seen only as providing the platform for this relationship through its structures and services. The study contributes to the literature on entrepreneurial failure by confirming that entrepreneurial failure influences the relationship with the church, but it also adds to the literature by indicating that the entrepreneur and the community of interest influence the relationship in different ways. Understanding how the relationship is influenced can guide other communities of interest in how they respond to failed entrepreneurs, and how the entrepreneurs’ relationship before the business failure determines how the relationship with the church is influenced after the failure. This study was conducted within a specific context, in South Africa, and amongst one specific religious community. Future research in different contexts and settings is needed to test the outcome of this study.
The rules of the game: business elite behaviour in limited access orders
Sisulu, Shaka (University of Pretoria, 2025)
Academic interest in the impact that business (or economic) elites have on national institutions has risen alongside global inequality. The question is more compelling within emerging markets which vary significantly in their institutional complexity. On the one hand economic elites may choose to buttress autocrats, on the other they have precipitated democratisation in authoritarian states. What remains unclear, is the impact a country’s institutional context has on business elites choices. Using Social Order Theory’s limited access orders (LAO) construct, which differentiates states by how much access to political and economic institutions is restricted, this qualitative case study interviewed 40 business and 8 other elites across the Democratic Republic of Congo, the Kingdom of Eswatini, Côte d’Ivoire, and South Africa. Each country represents a different LAO typology, namely: Fragile, Basic Authoritarian, Basic Competitive-Clientelist, and Mature. The research reveals how institutional context does constrain business elite behaviours in LAOs. The structural power of economic elites, a determinant of their choices, is enhanced by consolidation mechanisms. Where elites had institutionalised means of developing consensus, their states were more ready for a transition to a more open order. In a virtuous cycle, economic elite influences rises as LAOs fulfil the doorstep conditions required for such a transition. These findings advance the understanding of how transitions between social orders could be operationalised and the roles of business elites within elite coalitions, which were little defined before in the literature. It is axiomatic that the work also contributes to elite theory. Future research should examine how the orientation of economic elites motivates them to pursue elite consensus.
Apologising for organisational misconduct: the journey towards stakeholder reconciliation
Pogrund, Gidieon (University of Pretoria, 2025)
Organisational misconduct harms and offends stakeholders, damaging relationships with them. There are normative and instrumental arguments for why it is important for organisations to reconcile these relationships, a pursuit which begins with apology. But while organisational apologies have proliferated, many have failed to generate full, or even partial, reconciliation with stakeholders. Despite the significant attention that these phenomena have received from management scholars, the challenges and complexities associated with organisational apologies, and achievement of stakeholder reconciliation, remain under-theorised in the management domain. I therefore explore these phenomena, doing so in the context of multinational organisations implicated in state capture-related corruption in South Africa during the period 2012-16. My questions seek to describe different organisational apology journeys in response to misconduct, explain why these journeys might produce different levels of stakeholder reconciliation, and prescribe how organisations should apologise to stakeholders. To answer these questions, I develop conceptual frameworks which synthesise the management and other literatures, including politics, history, sociology, theology, philosophy and psychology. Using the Gioia methodology, I extend these frameworks through an investigation of leaders’ lived experiences of organisational apology journeys. My study establishes a framework prescribing what an ideal organisational apology should include, and why, how, when, and by whom it should be issued. My findings show that the prospects for stakeholder reconciliation depend on whether organisations embrace, finesse or reject this framework, as well as on several exogenous conditions: the economic role and services of organisations; the impact of time; differences in stakeholder attitudes; the possible impossibility of forgiveness; and stakeholder weaponisation of apologies. In some cases, an ideal apology may be a necessary but insufficient condition for stakeholder reconciliation; in others, it may be an unnecessary condition, with a partial apology sufficing. This study contributes theoretical insights about the complex interrelationships between these phenomena. These insights are relevant to organisational apologies for diverse types of misconduct, and can be turned into a road map or testable concepts for future research. The study’s recommendations about how to navigate challenges and more effectively implement the prescriptive framework can benefit apologising organisations, their harmed and offended stakeholders, and broader society.
The influence of emotional labour on emotional exhaustion across communication modes in a collectivist context
Kambikambi, Musonda Matildah (University of Pretoria, 2025)
The elevated use of videoconferencing in the workplace has highlighted a gap in understanding how emotional labour contributes to emotional exhaustion. This study investigates the influence of emotional labour on emotional exhaustion within a collectivist context, illuminating differences between videoconferencing and in-person communication modes. This concern has become increasingly relevant due to rising rates of emotional exhaustion attributed to the use of videoconferencing in supporting practices such as remote and hybrid work. While prior literature has established a connection between emotional labour and emotional exhaustion during in-person interactions, the relationship in videoconferencing scenarios remains underexplored. Further, the consistency across both modes has seldom been investigated. Drawing on affective events theory, this thesis posits emotional labour as a key influence on emotional exhaustion and investigates how this relationship differs between videoconferencing and in-person interactions. Data were collected from 105 human resources professionals in Zambia using experience sampling method across seven days. To test the theoretical assumptions, structural equation modelling was then applied. Findings indicate that both emotional labour strategies, surface acting and deep acting, impact emotional exhaustion regardless of communication mode. This relationship is positively moderated by negative mood. Notably, the results around videoconferencing reveal that emotional exhaustion increases when either the participant or their co-worker has their camera turned off, suggesting that emotional exhaustion is influenced by features of videoconferencing. This research enhances comprehension of emotional labour and emotional exhaustion by examining this relationship across two distinct communication modes in a collectivist context. The study also benefits practitioners by garnering information around video camera usage, which is suggested to play a role in users' emotional experiences during videoconferencing. Ultimately, the study enriches the discourse on emotional labour, providing novel insights pertinent to today's globalised workplace.
Exploring governance and value creation in regional value chains
Ambrosio, Natasja (University of Pretoria, 2025)
Regional value chains (RVCs), constituting the manufacture and supply of products to proximal markets, have emerged from the combined demand for shorter lead times and supply chain transparency on the part of lead firms, and protectionist trade policies on the part of the government. Scholars have identified this as an opportunity for emerging markets, but they have raised concerns about how these regions can advance their RVC competitiveness while simultaneously securing sustainable development outcomes. Emerging market MNEs (EMNEs) play a role in governing RVCs to drive development and gain value chain advantages, while also experiencing the competing demands of business and society. The research question explored how an EMNE governs its regional suppliers, how value is created, and how governance relates to value creation. An embedded multiple-case study of regional value chains in Southern Africa was conducted from a pragmatic perspective, aiming to understand the complexity of the challenges faced by firms in the RVC. Using company data, semi-structured interviews, and questionnaires with decision-makers from an EMNE and its regional suppliers across four different value chains, data were triangulated and compared at both the EMNE and value chain levels. The embeddedness of the RVCs in Southern Africa was an important context, as unemployment and levels of inequality in the region are significantly high. Therefore, it is unsurprising that the RVC participants across the four value chains focused strongly on the challenge of unemployment and mitigating its impact on the market. The findings revealed that while the EMNE understood the impact of its actions on the market and the broader regional value chain, the lack of investment presented a risk to secure sustainable RVCs. In response to this, a cost-capability-collaboration (3C) framework was developed to enable a targeted approach to achieve both cost competitiveness and capability investment through collaboration, and where the context becomes an active agent in the process. By applying the framework, RVCs can collaborate more strategically to invest in the capabilities required to embed a more sustainable path for the RVCs. With the 3C framework, this research makes a theoretical and practical contribution to RVC and EMNE literature.
Inter-site movements and associations of southern elephant seals (Mirounga leonina) ashore at Marion Island
Church, Erin Claire (2018)
Southern elephant seals (Mirounga leonina) periodically haul out on Marion Island during the year to moult, breed, or to rest. During a haul-out period, elephant seals generally remain ashore until they have finished moulting, breeding or resting, although movement between beaches on the island during a haul-out may occur. Simple descriptive analyses of the available longitudinal mark- iv resighting data gathered on this population between 1983 and 2013 showed that a proportion of the southern elephant seal population at Marion Island change haul-out location within the haulout periods. Through further multiple logistic regression analyses, these movements were found to be influenced by several demographic factors, including sex, age, and breeding status, as well as behavioural factors, such as haul-out period, and environmental factors, such as haul-out location. Within the four different haul-out periods included in this study (the natal, moulting, breeding and winter haul-outs) male elephant seals moved haul-out location significantly more than females, and younger elephant seals move significantly more than older individuals. The moulting season haulout had the greatest proportion of haul-out location changes within a season and the breeding season the smallest. Several beaches showed higher proportions of seal influx than other beaches, revealing a definite beach preference by elephant seals at Marion Island. During haul-out periods, elephant seals form aggregations, and associations between individuals were investigated as explanatory variables of the observed inter-site movements. Multiple regression quadratic assignment procedure (MRQAP) and generalized affiliation index (GAI) indicated that the inherent gregariousness of the species, as well as age, were the most powerful variables to predict whether seals showed any degree of preferred or avoided association within the population. When controlling for all presumed confounding factors, there was significant evidence for long-term preferred or avoided association between individuals across the 31 years of this study. However, there was little indication that these associations would affect inter-site movement dynamics. Intersite movements could possibly be due to many different factors, including a type of avoidance behaviour in females due to harassment from secondary males, or inbreeding avoidance of southern elephant seals at Marion Island.
Behaviour and design of unstiffened steel column base connections under uniaxial and biaxial bending
Cloete, Renier (2017)
Very little guidance exists on the design of steel column base connections for biaxial flexure combined with axial compression. This study aims to develop a design method for designing these connections for combined loading. To this end, an extensive experimental programme that consisted of 32 tests to failure, was carried out. The programme varied plate thickness, holding-down bolt diameter, axial force level and loading angle. Ancillary tests were carried out to establish material strengths and to assess the importance of bond to the design of the connection. The programme was augmented with detailed finite element analyses that were calibrated with the experimental results. It was found that the contribution of bond to the final anchorage strength of the connection is negligible and should be ignored. Very little concrete damage was observed during the experimental phase and current design guidance for concrete bearing strength is very conservative. Increases in plate thickness, holding-down bolt diameter and axial force were found to increase the connection strength. Increases in loading angle, from strong-axis to weakaxis bending were found to decrease connection strength. Furthermore, the plate thickness and holding-down bolt parameters were found to be interdependent. Increases in axial compression were found to increase the initial connection stiffness. Finally, a new mechanical model is proposed for designing base connection. The model enables the construction of thrust-moment interaction diagrams that can be used directly for design. A shortened listing of the source code used to generate the interaction curve in this work is included in the Appendix.
Horizontal gene transfer in eukaryotes, with special focus on the nematode Deladenus siricidicola
Clasen, Frederick Johannes (2017)
Horizontal gene transfer (HGT), the movement of genetic material between different species, is a well recognized mechanism for rapid evolution and adaptation in prokaryotes. It was not until fairly recent that the existence of HGT in eukaryotes have also been appreciated to such an extend that it is recognized as a fundamental evolutionary driving force for adaptation. Here we review the most recent work that explored the horizontal transmission of genetic material in eukaryotes. Firstly, different biological and computational limitations that currently constrain HGT research in eukaryotes are highlighted. Secondly, several examples of HGT in eukaryotes are discussed to emphasize its potential on the evolution of complex organisms. The importance of endosymbiosis is accentuated by using it as a model system for the evolutionary importance and underlying mechanisms of HGT. Other examples of where HGT allowed species to adapt to new ecological niches, expand their metabolic capabilities and adopt entire new lifestyles are then used to sketch the influence of HGT on specific eukaryotic species. Thirdly, the potential impact that HGT may have on our perception of the tree of life is discussed using different examples of HGT in all domains of life. Lastly, genes that are frequently transferred between organisms are summarized with specific reference to genomic islands that can potentially act as “genomic vehicles” of HGT in eukaryotes, similar to its role in prokaryotes.
Spatial distribution of bovine trypanosomiasis in Malawi
Chimera, Elizabeth T. (2017)
No abstract available
Testing sex ratio optimality in southern African pollinating fig wasps
Chung, Yi-Po Nico (2016)
We developed a game-theoretic model using Monte Carlo methods to predict the evolutionary stable strategy (ESS) for offspring sex allocation for simultaneously ovipositing foundresses in haplodiploid species under local mate competition (LMC). Although it was developed specifically for the fig-fig wasp interaction, the model can be generalised to other systems. The model simulates passive sex ratio adjustment via constrained oviposition of offspring eggs. The proposed mechanism results from simultaneous initial oviposition of male eggs followed by constrained oviposition of female eggs. The model incorporates a high degree of ecological detail and accounts for variable foundress number, patch size, egg load and offspring mortality distributions. We tested how these variables affect the ESS. Model predictions are in qualitative agreement with current sex ratio theory. We also developed a set of parameter estimation methods for modelling species data. The model in conjunction with the parameter estimation methods explains observed species data. This is the first model to make quantitative sex ratio predictions for single foundress patches
Essays on political economy in sub-Saharan Africa
Chisadza, Carolyn (2017)
Modernisation encourages changes in economic and political development. This research studies modernisation processes in the sub-Saharan African region which are linked to political and economic development over the past 50 years. The Örst paper investigates the determinants of democracy using Lipsetís (1959) modernisation hypothesis. We Önd that previous empirical works that focus on income per capita as the main indicator for economic development may have understated the e§ects of other determinants such as education, urbanisation and industrialisation which are equally important in the process of development. We reÖne the methodological approach by using principle component analysis to create an íeconomic development íindex that combines the common factors in income per capita, education, urbanisation and industrialisation. We Önd robust results for the modernisation hypothesis in sub-Saharan Africa unlike previous works. The second paper investigates the fertility transition following several hypothesis put forward in literature as triggering fertility declines. The results indicate that in the absence of technological advancement, income per capita and infant mortality signiÖcantly lower fertility rates. However, when we introduce technology through instrumental variables, the macro-evidence places the region in a transitional phase from a Malthusian to a late Post-Malthusian period with education and industrialisation playing a signiÖcant role in contributing to the changes in fertility decisions. Further evidence from female education lowering fertility rates validates the results that the region is modernising and slowly abandoning traditional views about the role of women in societies. The third paper investigates the historical processes described by Pinker (2011) as reducing conáict. These include the paciÖcation and civilising processes, the humanitarian and rights revolutions, and the long periods of peace after World War II and the Cold War. We view these processes as encompassing globalisation, and hypothesise that globalisation and all it entails has created incentives that increase the opportunity cost of conáict. We Önd robust results for the pacifying e§ects of globalisation on conáict, even with the inclusion of commonly used conáict determinants such as income per capita, education, resource rents and democracy. Despite the delays that are associated with a transitioning phase, the evidence from the three papers indicates a modernising region that is progressing towards higher levels of economic and political development.
Host immune response profiles of calves following vaccination with live and inactivated mycobacterium bovis vaccine candidates
Chileshe, Josephine (2016)
The aim of this study was to evaluate and compare the cell-mediated and humoral immune responses elicited in cattle by three different vaccine formulations (live M. bovis BCG, formalin inactivated M. bovis BCG and heat killed M. bovis). A total of 24 calves were used in this experiment, three out of four treatment groups of 6 calves each were vaccinated by the subcutaneous route with one of the three vaccines while one group of 6 calves served as control. Animals were subjected to the tuberculin skin test and sampled at prescribed times to assess host systemic immunity in terms of interferon gamma (IFN-_) response, using Bovigam® and antibody levels using an IDEXX® M. bovis antibody test and compared between the four treatment groups. Results show that subcutaneous vaccination with killed whole M. bovis cells and live BCG elicited detectable cellular and humoral immune responses in cattle. While the killed BCG vaccine formulation only induced cell mediated immunity. The treatment group which received the heat killed M. bovis vaccine showed the most significant increase in the IFN-_ ix responses directed against bovine tuberculin (PPD-B) from 4 weeks post vaccination to the end of the experiment. Bovine TB-specific humoral responses represented by IgG antibodies were not detected in the group vaccinated with formalin inactivated M. bovis BCG. The groups vaccinated with live M. bovis BCG had detectable but low levels of antibody responses and heat killed M. bovis had high levels of IgG antibodies, respectively. The latter indicated stronger host immune responses in the heat killed M. bovis group as compared to the live M. bovis BCG vaccine and the formalin inactivated M. bovis BCG vaccine groups. In conclusion, levels of immune responses detected indicate a superior cell-mediated and humoral immune response of the heat killed M. bovis group, which makes it a suitable vaccine candidate for field trials. In addition, the advantages of the use of heat killed M. bovis vaccine as compared to a live M. bovis BCG vaccine formulation are i) the killed M. bovis vaccine would not shed into the environment and ii) the potential health risk for immunecompromised individuals of live BCG is ruled out.
Sustainable tourism and community participation in transfrontier tourism development : case of the Sengwe Community and the Great Limpopo Transfrontier Conservation Area (GLTFCA)
Chiutsi, Simon (2016)
Since the inception of the Great Limpopo Transfrontier Conservation Area (GLTFCA), which happens to be the flagship transfrontier tourism destination in southern Africa, there has been a great deal of optimism about communities development and livelihoods development through transfrontier tourism. Admittedly the GLTFCA has been a battle ground for scholarly attention interrogating the multiple objectives of the GLTFCA which include biodiversity conservation, growth of the tourism sector, regional cooperation and socio-economic development. Due to the multinational packaging of the GLTFCA there has been concern that it is excluding and further marginalising the local communities who happen to be one of the key stakeholders in this transfrontier tourism destination. As a result the study comes to make its contribution towards understanding community participation in transfrontier tourism and the projected livelihood changes that have been largely associated with the GLTFCA initiative. This research explores the extent to which livelihood strategies have been transformed in the GLTFCA with particular focus on the Sengwe community, by investigating the extent to which the local communities have been involved in the transfrontier destination through sustainable tourism and biodiversity conservation. The research objectives are; to assess community participation in conservation and tourism entrepreneurship; analyse community members perceptions towards the GLTFCA; to generate knowledge of community integration in conservation and tourism opportunities. The theoretical framework of the research is based on the key concepts of transfrontier conservation, sustainable livelihoods development and community based tourism (CBT) in transboundary conservation. The study is mainly based on qualitative approaches but aims to utilise also the benefits of quantitative analysis. Research material was collected between March and October in 2013 by using structured interviews as many rural community members are not often able to respond independently to a questionnaire kind of questions.The research concludes that the local community members from the Sengwe area in the GLTFCA remain largely alienated from the key tourism activities currently operational in the transfrontier destination and that the GLTFCA lead agencies have not meaningfully involved the local people in their programmes. As a result the local people are largely negative about the prospects of tourism driven livelihoods in the GLTFCA due to the realisation that local participation in sustainable conservation and ecotourism is subdued and weak. As such the dominant livelihood strategies have remained largely crop farming and livestock rearing as the tourism industry vi is not meaningfully availing opportunities for community participation. There is a greater concern from the local people in Sengwe which happens to be a key stakeholder in the GLTFCA that the hype and excitement associated with ecotourism in this transfrontier tourism destination have not been meaningfully availed to the people since the inception of the transboundary conservation arrangement in 2002. In recommendation, the success of tourism and livelihoods sustainability needs a positive enabling environment in which local community members are meaningfully engaged and not to bring down the objective of community participation to merely rhetorical or tokenistic levels. There is need to improve transfrontier governance and facilitate community participation through partnerships with both the private and public sector. There is need for the GLTFCA lead agencies to promote programmes which improve livelihoods sustainability as these will increase the perceived utility of GLTFCA by the local people. This in turn could guarantee increased trust and collaboration of the local people towards the GLTFCA primary goal of biodiversity conservation. One of the key findings is that the worsening socio-economic conditions and political instability in Zimbabwe since 2000 has negatively affected tourism growth and conservation funding in southeast Zimbabwe and there is need for the government and other key stakeholders to work towards restoration of socio-economic and political stability so that Zimbabwe regains its destination competitiveness.
Identification and resistance profiles of Cladobotryum spp. pathogenic on Agaricus bisporus (Lange) Imbach
Chakwiya, Alinesi (2018)
There are about 50 species of Cladobotryum which represent a genus that is fungicolous both on the wild and cultivated mushrooms. Several species affect white button mushrooms (Agaricus bisporus (Lange) Imbach) and are recently among the most commonly encountered fungal pathogens in mushroom growing regions of the World. In recent years, cobweb has emerged as one of the major fungal diseases of cultivated mushrooms causing losses due to brown spotting and premature termination of the crop. Losses of 40-90% have been reported in some countries where cobweb disease has been prevalent. Due to the importance of cobweb disease to the industry around the world it has become increasingly necessary to understand the pathogen in terms of different species of Cladobotryum that cause disease, the importance of each species with regards to aggressiveness and adaptation to fungicide use, and for future more effective development of control methods. In order to achieve this aim four key objectives were covered which included; a) investigation of the morphological diversity of different C. mycophilum associated with cobweb disease for rapid identification and control; b) using proteomic characteristics through Mass Adsorption Laser/Desorption Time Of Flight (MALDI TOF MS) to identify Cladobotryum spp. separate isolates and species and understand their relatedness; c) examination of the host-pathogen interactions between A. bisporus and Cladobotryum spp. in cobweb disease development and; d) determination of in vitro sensitivity of C. mycophilum and C. dendroides to prochloraz manganese and carbendazim, the commonly used fungicides. A database was established using the isolates that were identified as C. x mycophilum (NCBI) and also C. dendroides, using the ITS, RPB1 and RPB2, alpha translation elongation factor 1 genes for use in the comparison between/among isolates and species. Among the isolates under study, it was observed that three distinct proteins were common in the genus Cladobotryum. Only one isolate represented C. dendroides while the rest were recognised as C. mycophilum, by its teleomorph – H. odoratus. Conidial and cultural morphology on malt extract agar were used to identify colony characteristics of both the known Cladobotryum and unknown species. Most of the conidia were ellipsoidal, oblong and cylindrical. Determination of the isolates’ interaction with the host was conducted for all the isolates to estimate the different relations exhibited between the isolates/strains. The isolates under study produced different levels of infection on basidioms, but similar characteristics with mushroom mycelia. Neither necrosis nor any penetration structures were observed. All isolates were exposed to fungicide treatment using the poison plate method. Isolates from the USA were used as a standard for comparison in terms of prochloraz manganese as it is not registered for use in the country. Varying levels of sensitivity to the two fungicides were noted among the Cladobotryum spp. examined. Identification using MALDI TOF MS repeatability showed 100% identification for the isolates matched against the data base. Different textures of colony morphology were expressed by C. mycophilum with the most prevalent being yellow/pinkish cotton fluffy with extensive dry conidia. Cladobotryum dendroides culture morphology was consistently observed as white cotton fluffy compact mycelia turning purple on the underside after more than 96 h. In conclusion, identification of the isolates under investigation can effectively be achieved using different standard and molecular methods. The technology platform developed in this thesis can now be used to rapidly identify different species in mushroom production systems. Monitoring for resistance development is encouraged as this study revealed that naturally occurring isolates with less sensitivity to the test fungicides are present within the mushroom growing farms in South Africa.
Generally Weighted Moving Average control charts for small shifts
Chakraborty, Niladri (2017)
No abstract available
Existence and stability of fixed point sets of multivalued mappings in b-metric spaces with applications
Ali, Basit (2017)
The aim of this research is to investigate the existence and stability properties of fixed point sets of multivalued mappings in the setup of b-metric spaces. Czerwik (1993) introduced b-metric spaces as generalization of metric spaces. These spaces are semi-metrizable and hence are first countable. The distance function used in b-metric spaces is not continuous in general. Triangular inequality involves a constant greater than or equal to one (called b-metric constant). Unlike metric spaces, open balls are not open and closed balls are not closed sets in general in sequential topology on b-metric spaces (An et al., (2015)). The first main problem that is addressed in this thesis is the existence of fixed point sets of multivalued mappings that satisfy generalized Suzuki type contraction conditions in b-metric spaces. This class includes the class of mappings satisfying various contractions like Kannan, Edelstein strict contractions, Suzuki type contractions and strict contractions, Ciric quasi-contractions, admissible multivalued contractions, almost contractions and Banach contractions. Existence of fixed points of multivalued mappings further provided the existence of coincidence and common fixed points of hybrid pairs of mappings in b-metric spaces. After setting the problem of existence of fixed points of such mappings, the second part or problem is related to the stability properties of fixed point sets of multivalued mappings and fixed point inclusions. Regarding this we discuss the problem of data dependence of fixed point sets, that is to find an upper bound for the Hausdorff distance between the ii fixed point sets of two multivalued mappings. Moreover, we study the stability of fixed point sets of uniformly convergent sequence of multivalued contractions on b-metric spaces, that is if a sequence of multivalued operators converges uniformly to a limit operator, then the corresponding sequence of fixed point sets converges to the fixed point set of limit operator. Generalized Ulam-Hyers stability of fixed point problems related to admissible multivalued mappings of b-metric spaces has been discussed as well. Another important issue is the completeness problem, that is to know under what circumstances, the underlying space is complete. One approach is to study completeness characterization via fixed point theory. In this research, a fixed point theorem for multivalued mappings further yields a completeness characterization of underlying metric space. Note that Banach contraction principle does not characterize completeness of underlying metric space (Connel (1959), Elekes (2009)). Some results obtained in this research have found some interesting applications. The scope of the applications is not limited to the ones presented in this study. A result have been applied in best approximation theory to prove the existence of a point in the intersection of fixed point sets and the set of best approximations. Further, existence of multivalued fractals, solutions of functional equations that arise in connection with dynamic programming, delay differential equations, have been obtained as applications. A local fixed point theorem is obtained and applied in a homotopy result. To obtain the main results in this thesis, we use method of successive approximations, topological properties and tools from the theory of b-metric spaces and set valued analysis. Contraction conditions involve b-metric constant and some auxiliary functions such that the analogous metric version of these conditions still generalize the existing contraction conditions. Further, comparison based on examples and remarks shows that the obtained results generalize, extend, and unify the results in metric fixed point theory of multivalued valued mappings.
Essays in monetary and fiscal policy
Chesang, Laban Kiptui (2014)
This thesis analyzes important monetary and fiscal policy issues in applied/empirical macroeconomics. The study is motivated by the events surrounding the recent 2007-08 global financial crisis and the desire of policymakers the world over to stabilize the economy through appropriate monetary and/or fiscal policy. The crisis has left many nations vulnerable to economic uncertainty, which has hindered economic growth. It is often the belief that, for government to recover from such crisis, it would tighten its monetary and/or fiscal policies. However, recovery is usually slow because the crisis increases economic policy uncertainty which policymakers often are unequipped to deal with or respond to poorly. In view of this, this study is relevant for policymakers in terms of improving their understanding of the behaviour of important macroeconomic variables and their implications for monetary and/or fiscal policy decision making. The thesis consists of three independent chapters besides the introduction and conclusion, and it is structured in two main parts. The first part includes chapters two and three, and it focuses on monetary policy. In chapter two, we addresses the issue of whether or not the transmission of bank lending shocks and the dampening thereof by monetary policy depend on the state of the banking sector. Chapter three examines the likely impact of uncertainty in the output-inflation trade-off on inflation using a monetary model in which central bank preferences are asymmetric over inflation and output. Fiscal policy issues are analyzed in the second part (chapter four), in which we use a dynamic stochastic general equilibrium (DSGE) model to analyze the macroeconomic impact of fiscal stimulus. We subsequently present a brief summary of each chapter. Chapter two investigates the hypothesis of nonlinear interactions between bank lending, volatility and monetary policy while taking into account the state of the banking sector, with the view of vi i assessing the role of the banking sector in business cycle dynamics. This is done by employing a Markov switching structural Bayesian vector autoregression (MS SBVAR) model along the lines of Sims and Zha (2006) and Sims, Waggoner and Zha (2008) on South Africa_s monthly data for the period 1966:M4 to 2011:M12. The model allows for time varying parameters in monetary policy and volatilities in bank lending shocks. We identify a number of episodes with high volatility in bank lending, and show that these episodes have corresponded to different monetary policy responses. Specifically, it is revealed that, regimes corresponding to high volatility in bank lending are associated with a monetary policy regime that is less aggressive to inflation but more responsive to output and bank lending. Loan supply shocks are found to have real effects in the economy. We also find evidence indicating that loan supply shocks and aggregate demand shocks, which generate inflationary pressures, account for a huge contribution in fluctuations in bank lending. This chapter underscores the role of the SARB in maintaining not only price stability, but also timely regulations of the financial system in general, in order to reduce episodes of volatile financial system. Chapter three examines the implications of uncertainty in the output-inflation trade-off for inflation dynamics, using a monetary model which features central bank asymmetric preferences over inflation and output. The uncertainty is modelled by exploiting the Lucas_ (1973) signal extraction model, in which the slope of the Phillips curve depends on the volatility of monetary policy. The task undertaken in the chapter is to solve under discretion for the reduced form process for inflation from the central bank_s optimization problem while taking into account the uncertainty about the slope of the Phillips curve. The focus is on the model with asymmetric preference although we begin initially with the model with quadratic preferences over inflation vi ii and output. Empirical estimation is implemented using Maximum Likelihood on South African data, for several variants of the model describing inflation behaviour. Our results show that in general, the models with uncertainty dominate those with certainty equivalence in terms of overall goodness of fit, implying that uncertainty about the trade-off adds significant information that helps policymakers interpret inflation. It is revealed that the implication of uncertainty about the trade-off is two-fold: firstly, it causes the interaction of output and volatility of monetary policy to influence inflation movements: in which case, we find significant evidence suggesting that higher volatility in monetary policy causes inflation to rise. Secondly, as suggested in an optimal rule, it causes output to contract by less whenever inflation increases above the target, and to expand by less whenever inflation is below the target. Other results indicate that the data seems to favour the model with asymmetric preferences to inflation only, relative to the one with asymmetric aversion to both inflation and output. This perhaps emphasizes SARB_s primary role of maintaining price stability. Moreover there is evidence suggesting that central bank seems to penalize more for inflationary rather than deflationary pressures. Overall, our findings appear to show that while SARB_s preferences are in line with her main role of maintaining price stability, the bank_s deflationary bias would allow for a relatively flat output-inflation trade-off. In turn, this would be helpful for economic stability. The subject matter investigated in the second part of the thesis concerns the role of fiscal stimulus in the economy. During crisis periods governments announce major stimulus packages designed to stimulate a weak macroeconomic environment. The use of fiscal policy to stabilize the economy can be justified on two grounds: first, at the zero-lower bound, interest rate adjustment becomes ineffective (Spilimbergo, 2008; Feldstein, 2009; and Christiano et al., 2011); and secondly, with a large share of agents in the economy being credit constrained, fiscal stimulus can induce ix expansionary effects by raising their current incomes (Furlanetto, 2010). In view of this, in chapter four, we employ the New Keynesian dynamic stochastic general equilibrium (DSGE) model to analyze the macroeconomic implications of fiscal stimulus. The objective is to replicate the standard results in the literature for broad or general government spending and contrast them with that of targeted spending, via wage subsidy granted to domestic firms. The model features credit constrained consumers and wage rigidity in the labour market. Our results indicate that contrary to broad government spending which induces a negative wealth effect on Ricardian consumers, a novel channel is established through which targeted spending viz-á-viz wage subsidy raises consumption of both Ricardian and non-Ricardian consumers. Consequently, wage subsidy generates a larger increase in aggregate consumption than pure demand stimulus. Furthermore, unlike broad government spending which in inflationary, wage subsidy operates directly through an additional supply side channel which alters relative factor prices, causing firms_ marginal cost and consequently inflation to fall. Overall the study demonstrates the role of wage subsidies in stimulating consumption, output and job creation in the economy. The relevance of this chapter lies in its contribution to the policy debate on the potential gains of a wage subsidy program that is soon to be implemented in South Africa and other developing countries.
Mafura seed oil : improvement in oxidative stability
Chemane, L.N.G. (2016)
Trichilia emetica seeds are processed for their oil by rural communities in the South of Mozambique. Traditionally, the oil is extracted by boiling the seed pulp in an aqueous medium for 5 h and recovering the clear yellow oil. The extended heating period and the use of water for oil extraction may reduce the oil quality. Mafura oil was extracted using a laboratory method that mimics the traditional method. Acid value (titrimetry), iodine value (Wijs method), saponification value (titrimetry) and fatty acid composition (gas chromatography) were determined in comparison with sunflower and olive oils. Oxidative stability (OS), (peroxide and anisidine values) of mafura oil stored at (65oC) over a 14 day period was also determined in comparison with sunflower and olive oils. The effect of refining, solvent extraction (hexane and ethanol) and the effect of incorporation of freeze dried crude phenolic extract (CPE) from red condensed tannin sorghum bran (at 1000 and 2000 ppm) compared with tertiary-butylhydroquinone (TBHQ) (200 ppm) on OS of mafura oil during storage was determined. Whole grain, bran and CPE were analysed for total phenolic content (TPC), (Folin-Ciocalteu assay) and antioxidant activity, (ABTS radical scavenging). Phenolic composition of the CPE was determined using High Performance Liquid Chromatographic. vii Traditionally extracted crude mafura oil (CMFO) had the highest acidity. Crude and refined mafura oils had the lowest iodine values and the highest saponification values compared with sunflower oil and the olive oils. CMFO was rich in palmitic acid, sunflower oil in linoleic acid and the olive oils were rich in oleic acid. CMFO was the least stable during storage as shown by high anisidine values. Solvent extraction (but not refining) improved the OS of CMFO. Mafura oil treated with CPE was more oxidatively stable than the control and this seemed to be dose-dependent. CPE at 2000 ppm was less effective in inhibiting the formation of primary oxidation products than TBHQ, however, it was as effective in reducing secondary oxidation. The CPE had higher TPC and antioxidant activity than whole grain and sorghum bran. The CPE contained phenolic acids and high levels of (+)-catechin and (-)-epicatechin. The ability of the CPE to improve the OS may be related to the action of the phenolic compounds as primary antioxidants in scavenging free radicals. This study shows that the traditional method of mafura oil extraction decreases its OS due to extensive heating in an aqueous medium. The CPE may potentially be used as a natural antioxidant to prevent oxidation of mafura oil due to the antioxidant properties of the phenolic compounds present in the sorghum bran.
Authentic leadership, organisational citizenship behaviour and intention to quit : the role of psychological ownership
Casaleggio, Riandi (2017)
Orientation: Organisations in the modern, complex and turbulent business environment are faced with several challenges, which include employee retention, commitment, satisfaction and turnover. Authentic leadership and psychological ownership have important implications for these challenges. Solving these challenges requires the provision of empirically derived research regarding authentic leadership and psychological ownership and the influence these constructs have on job-related behaviour. Research purpose: The purpose of this study is to examine the influence of perceived authentic leadership on followers’ citizenship behaviour and their intention to quit their jobs as well as to explore the role that psychological ownership has to play in these relationships. Motivation for the study: Although previous studies found that authentic leadership predicts psychological ownership and that authentic leadership as well as psychological ownership lead to several corresponding outcomes, the researcher believes that the possible mediating effect of psychological ownership should be investigated. The mediating effect of psychological ownership between authentic leadership and organisational citizenship behaviour and authentic leadership and intention to quit have not been explored in previous studies. Research design, approach and method: A quantitative cross-sectional design was used on a convenience sample employed within the South African service industry (N = 384) to explore relationships between authentic leadership, psychological ownership, intention to quit and ix organisational citizenship behaviour. MPlus was used to perform structural equation modelling to appraise the hypothesised model. Main findings: Authentic leadership had a significant positive relationship with organisational citizenship behaviour and a significant negative relationship with employees’ intentions to quit. Furthermore, the results indicated that authentic leadership had a significant (medium) indirect effect on organisational citizenship behaviour through psychological ownership and a significant (small) indirect effect on intention to quit via psychological ownership. Practical implications: This study provides organisations with a better understanding of how authentic leaders can create a positive, healthy, working environment and how authentic leadership behaviours can influence followers’ organisational citizenship behaviour, psychological ownership as well as employees’ intention to quit. Contribution: This study contributes to the development of the nomological network of psychological ownership. A particular contextual factor, namely perceived authentic leadership’s influence on psychological ownership, is specifically investigated.
Neonate immunity, growth and puberty in dairy calves: Influence of dietary conjugated linoleic acid supplementation of the dam
Cardoso, Claudia (2016)
Colostrum provides the neonate calf with maturational, immune-modulatory and antimicrobial factors. Feeding isomers of conjugated linoleic acid (CLA) reportedly increases immunoglobulins (Ig) production in rats and circulating IGF-I levels in cows. The objective of the study was to evaluate the effect of CLA dietary supplementation of the dam on colostrum quality and calves immune system, growth and attainment of puberty. Thirty-four Holstein cows, blocked by parity, body weight and body condition score were randomly assigned to two groups: control (CTL) (100gr/cow/day of calcium salts) and CLA (100 gr/cow/day of CLA). Individual top-dressed supplementation started 20±7 days before calving until 35 days in milk. From day 0 to 3 each calf was individually fed its mother’s colostrum. The same was sampled for immunoglobulins G (IgG) quantification. Calves were bled every other day from 0 to 15 days for IgG and total protein (TP) levels. Weekly, from day 7 to 35, calves were bled for growth hormone (GH) and insulin-like growth factor I (IGF-I) quantification; furthermore body measurements and weight were recorded for growth rate. Attainment of puberty was monitored from five (males) and seven (females) months respectively. Monthly, body measurements and weight were recorded. In males, scrotal circumference (SC) was measured. Semen collection by electroejaculation was performed in animals with SC > 23 cm for evaluation of semen parameters (volume, colour, mass and individual motility, concentration). Puberty was declared with concentration of 50 million spermatozoa/ejaculate with at least 10% progressive motility. Females were bled fortnightly for progesterone levels, while ovarian activity was monitored by ultrasonography. Puberty was attained when a corpus luteum was present and progesterone levels were ≥ 1 ng/mL. 1 2 Data were analysed with SAS 9.3 (SAS Institute Inc Cary, NC). Average daily gain (ADG) of each animal was calculated between birth and weaning and between weaning and final body weight (300 days) by one-way ANOVA using the general linear model (GLM, SAS 9.3) including treatment and gender as fixed effects. For ADG at final weight, weaning weight was included as covariate. The same analysis was used to compare weights at birth and attainment of puberty, including in the model treatment and gender as fixed effects and dam’s weight as covariate. Levels of IgG, TP, GH and IGF-I were analysed by ANOVA using GLM, SAS 9.3 with a mathematical model where gender, treatment, age, interactions treatment/age and treatment/gender were the fixed effects while the calf was the random effect. Decrease rate of colostrum parameters were calculated by regression of concentration against time (PROC REG, SAS 9.3). Slopes were compared with F-test. When the effect of gender and its interaction with the treatment were significant, data were analysed separately by gender. Growth was analysed in two periods, weight to 35 days and 180 to 300 days by ANOVA using the proc. mixed model (SAS 9.3) were gender, treatment, age and interactions treatment x age were fixed effects while the calf was the random effect. Birth weight was used as covariate. Group and gender growth curves on the period 180 to 300 days were calculated by regression of weights against time (PROC REG, SAS 9.3). Regression slopes were compared with F-test. Significance was declared at P _ 0.05 while trend was declared at P _ 0.1. A trend of higher TP levels was detected in CLA calves (P _ 0.1). CLA male calves showed higher ADG pre-weaning (P _ 0.05) and growth rate from 180 days of age compared to control (P _ 0.01). Furthermore, a trend for higher SC (P _ 0.1) and significant major ejaculate volume (P _ 0.05) was observed in the CLA group. In conclusion, colostrum from CLA supplemented dams proved to have a supplementation time-dependant effect on calves’ ADG pre-weaning and carry over effects possibly mediated by improved feed efficiency on growth pre-puberty. However, it failed to alter age at attainment of puberty.

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