Assessing estuarine nursery habitats for Cape Stumpnose (Rhabdosargus holubi), (Pisces: Sparidae) in a warm-temperate estuary in the Eastern Cape, South Africa
- Authors: Leslie, Timothy David
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3178 , vital:20381
- Description: The nursery role hypothesis provides an approach for assessing the nursery function of habitat types within estuaries. This study attempted to assess the nursery value of the dominant estuarine habitats in the Bushmans Estuary for Rhabdosargus holubi (Steindachner 1881) by analysing habitat complexity, relative abundance and behaviour of R. holubi and using stomach contents analysis and dietary diatom composition as indicative of feeding habitat. Structural habitat complexity was assessed in Zostera capensis (Setchell) seagrass and Spartina maritima (Curtis Fernald) salt marsh by sampling above-ground stem density and length, and total cover per unit area (Ct/At). Dimensionless habitat complexity indices such as the interstitial spatial index (ISI) at three magnifications and fractal geometry at two magnifications were used to further analyse habitat complexity. Above-ground biomass (P<0.05) in each season and canopy height (P<0.001) were significantly higher in salt marsh than in seagrass whilst stem density was significantly higher in seagrass than in salt marsh in each season (P<0.001). Each dimensionless index indicated that complexity is notably higher in seagrass than in the salt marsh. Using dimensionless indices that analyse complexity at different spatial scales provided a better analysis of habitat complexity than canopy height and biomass as it allowed for direct comparisons between habitat types. Underwater video cameras were deployed in seagrass, salt marsh and sand flat habitats to assess the relative abundance and behaviour of R. holubi. The relative abundance of R. holubi was significantly higher in seagrass than salt marsh and sand flats, whilst the behaviour of R. holubi indicated a high degree of habitat use in structured habitats and a low degree of habitat use in unstructured sand flat habitats. This indicated that not only are juvenile R. holubi a vegetation-associated species, but also a species that prefers seagrass to salt marsh.
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Assessing the impact of climate change on mangrove crabs: the role of ontogenetic macrophysiology and settlement in the persistence of central and marginal populations
- Authors: Mostert, Bruce Petrus
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/826 , vital:19994
- Description: After a brief respite in the mid to late 20th century, macro physiology has come to the fore in elucidating large scale ecological patterns and processes as physiological assumptions often form the backbone of many predictive theories associated with species distributions. Critically, macro physiological patterns are valuable in explaining physiological variation across multiple scales and provide insights into the effects of climate change on populations spanning a wide range of latitudes. This can assist in predicting possible distribution expansions, contractions or shifts in light of current climate change scenarios. From this perspective, investigating intra- and inter-specific physiological responses to environmental stress may contribute to better understanding and predicting the effects of climate change on geographical ranges. Further, investigating the physiological effects to environmental stresses across ontogenetic stages allows for the identification of weak links within the lifecycle of a species. Additionally, determining settlement characteristics along a latitudinal cline provides integrated indications of the sustainability of populations, highlighting vulnerable regions in terms of repopulation of viable habitats. In this context, the present study aimed at establishing how temperature, in a physiological context, may affect reproductive biology of two species of mangrove crab, Perisesarma guttatum and Uca urvillei at the centre (Kenya) and edge (South Africa) of their distributional range along the east coast of Africa and highlight possible consequences for range distributions. A third species, Neosarmatium africanum, only in South Africa, was included to provide additional interspecies comparisons. Furthermore, settlement characteristics of brachyuran populations at the centre and edge of their distributional range were considered in order to determine how settlement may contribute to population persistence. Physiological investigations at the centre and edge of distributional range and across ontogenetic stages (larvae, stage 2 and 4 embryos, non-gravid and gravid females) under the concept of oxygen and capacity limitation of thermal tolerance (OCLTT), revealed that, for both species, populations at the centre of their distribution (Kenya) were generally more robust to increasing temperatures and generally displayed greater physiological stability with increasing temperatures compared to their conspecifics in South Africa. Variability in physiological robustness between regions, did however, differ among ontogenetic stages and species but, overall, were evident throughout. Within and between regions, adaptation to oxygen extraction in both milieus (air or water) was displayed for present temperature conditions but aerial respiration largely alleviated increased thermal stress due to overcoming the limitations of reduced oxygen availability and diffusiveness in water for all bimodal ontogenetic stages. Brooding eggs proved to be a physiologically critical process with either heighted oxygen consumption for gravid females or collapse of physiological processes demonstrated by supressed oxygen consumption. The physiological cost of brooding eggs, referred to as maternal costs, was reflected in in both Perisesarma guttatum and Uca urvillei where, in most cases, maternal costs were negative. Again, aerial respiration was able to alleviated increased thermal stress, as shown by positive maternal costs indicating sustained maternal care, but this mechanism was species and regionally specific. Settlement patterns differed between the edge and centre of distribution of the species studied. This difference was predominantly driven by zonal preference within the mangal and/or effects of new and full moon (lunar phase). Overall, settlement dynamics were more widely variable in South Africa, both spatially and temporally, than in Kenya. Finally, empirical physiological data from ontogenetic stages present during the reproductive process (early and late stage embryos) and from non-gravid and gravid females were used in conjunction with data mined from the existing literature to parameterise an individual based model designed to simulate reproductive output at the centre and edge of distribution of Perisesarma guttatum. Physiological data indicate that, in terms of reproductive output across increasing temperatures, populations based at the centre of their distribution presently outperform their counterparts at the edge of the species’ distribution, but reproductive output stagnated as temperature rose. Edge of distribution populations consistently increased reproductive output with increasing temperatures to eventually outperform centre of distribution populations at higher simulated temperatures. Overall, results of the physiological and settlement studies suggest that with increased climate change there may be a contraction of distributional range of the study species from high latitudes to low latitudes, contrary to general poleward shifts/migrations seen in most species, with possible contractions of the entire ecosystem mirroring the disappearance of keystone mangrove macrofauna.
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Assessing the value of public investment into biological control research for invasive alien plants : the ARC PPRI Weeds Research Division
- Authors: Scarr, Lowell Martin
- Date: 2016
- Subjects: Alien plants -- Biological control , Invasive plants -- Biological control , Alien plants -- Economic aspects , Invasive plants -- Economic aspects , Weeds -- Biological control
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1126 , http://hdl.handle.net/10962/d1020604
- Description: This study investigates the economic impact of the ARC PPRI Weeds Research Division. The Division researches appropriate methods of biological control for invasive alien plants (IAPs). These plants pose an increasing threat to environmental integrity and ecosystem service provision impacting on economic potential. Since the work of the Division is considered a public good, a predominantly descriptive approach has been adopted for the valuation process. A combination of quantitative cost analysis and a qualitative study of the impacts of research and invasive alien plants is used to deal with the challenges associated with non-market valuation. The study found that investment into the Weeds Division is a valuable activity that supports the long-term growth potential of the South African economy. The role of a well-functioning environment is highlighted as an essential base for the creation of sustained growth opportunities in any society. It was determined that investment into the Division should be increased into the future to support efficient spending of scarce state funds. Biological control research was found to provide strategic future growth potential, creating opportunities for the development of a competitive advantage in the biotechnology and environmental management sectors. The study adds to the increasing move towards a more holistic view of economic valuation, taking factors other than pure finance and econometrics into consideration. This is an important shift in prevailing economic thought, as a realisation is reached that a single, or even triple, bottom line is an outdated and insufficient decision making basis.
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Assessment of fluctuating asymmetry as an indicator of water quality stress in South Africa
- Authors: Holland, Alexandra Jennifer
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/430 , vital:19958
- Description: South Africa’s freshwater resources are facing numerous water quality challenges and need to be protected from degradation and pollution by appropriate management strategies as they are a limited and shared resource. The South African Scoring System (SASS5), which assesses macroinvertebrate communities at family level, is used in routine monitoring of riverine ecosystems in South Africa. Assessing the condition of these ecosystems is limited as SASS5 does not allow for changes at lower levels of biological organisation to be detected. Fluctuating asymmetry (FA) - small random deviations from perfect symmetry - is considered a direct measure of developmental instability. This phenotypical response results from numerous internal and external factors and has a low level of heritability. FA is based on sound scientific principles, easy to measure, biologically robust and cost-effective. It reflects synergistic interactions between stressors and provides an integrated measure of several anthropogenic stresses, which strengthens the assertion that FA is an environmental indicator of water quality stress, and can potentially be used to detect stress in populations before irreversible effects manifest. FA responses were investigated by (1) exposing freshwater shrimp to increasing concentrations of cadmium chloride in a long-term experiment and (2) comparing FA responses to water quality changes and macroinvertebrate community responses in two case studies (Kwazulu-Natal and Limpopo Province) in South Africa. Although no consistent concentration-response curve could be established, this study suggests that FA responses can be used as a sublethal endpoint in exposure experiments. Determining water quality parameters causing FA responses was not possible in field collected freshwater shrimp in either case study. Although FA did not specifically respond to any of the measured water quality parameters identified in the case studies, it has potential as a general indicator of water quality stress in freshwater shrimp. This study shows that FA responses are potentially more sensitive than macroinvertebrate community responses to pollution since it is not affected by habitat. Since FA has the potential to be a general indicator of population quality, particularly where there are natural habitat differences, it can be useful at the level of biomonitoring required for routine basic river status assessments in South Africa. However, in order for FA to become a robust tool that can be used routinely in conjunction with SASS5 more research is required.
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Bayesian accelerated life tests: exponential and Weibull models
- Authors: Izally, Sharkay Ruwade
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3003 , vital:20351
- Description: Reliability life testing is used for life data analysis in which samples are tested under normal conditions to obtain failure time data for reliability assessment. It can be costly and time consuming to obtain failure time data under normal operating conditions if the mean time to failure of a product is long. An alternative is to use failure time data from an accelerated life test (ALT) to extrapolate the reliability under normal conditions. In accelerated life testing, the units are placed under a higher than normal stress condition such as voltage, current, pressure, temperature, to make the items fail in a shorter period of time. The failure information is then transformed through an accelerated model commonly known as the time transformation function, to predict the reliability under normal operating conditions. The power law will be used as the time transformation function in this thesis. We will first consider a Bayesian inference model under the assumption that the underlying life distribution in the accelerated life test is exponentially distributed. The maximal data information (MDI) prior, the Ghosh Mergel and Liu (GML) prior and the Jeffreys prior will be derived for the exponential distribution. The propriety of the posterior distributions will be investigated. Results will be compared when using these non-informative priors in a simulation study by looking at the posterior variances. The Weibull distribution as the underlying life distribution in the accelerated life test will also be investigated. The maximal data information prior will be derived for the Weibull distribution using the power law. The uniform prior and a mixture of Gamma and uniform priors will be considered. The propriety of these posteriors will also be investigated. The predictive reliability at the use-stress will be computed for these models. The deviance information criterion will be used to compare these priors. As a result of using a time transformation function, Bayesian inference becomes analytically intractable and Markov Chain Monte Carlo (MCMC) methods will be used to alleviate this problem. The Metropolis-Hastings algorithm will be used to sample from the posteriors for the exponential model in the accelerated life test. The adaptive rejection sampling method will be used to sample from the posterior distributions when the Weibull model is considered.
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Being a black mine worker in South Africa: the case of Anglo Platinum Mine
- Authors: Maseko, Robert
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/651 , vital:19978
- Description: This thesis presents a decolonial perspective on the experience of being a black mineworker in post-apartheid South Africa with specific reference to the Platinum Belt. It seeks to understand what it means to be a black mineworker by unmasking and analysing the existence and prevalence of coloniality in contemporary South Africa despite the end of formal colonialism (i.e. apartheid). As a world-wide system, coloniality has different dimensions which all speak to and highlight continuities between the period of colonialism and the post-colonial period. These dimensions are coloniality of power, coloniality of being and coloniality of knowledge. The power structure of coloniality produces and reproduces the identity of the black mineworker in present-day South Africa as a sub-ontological being devoid of an authentic humanity such that the mineworker is depicted as incapable of rational thought and knowledge. The existential condition of the black mineworker is symptomatic of the generic experience of being a racialised subject of colour in the current global power structure predicated on the dominance and hegemony of Western-centred modernity. The black mineworker exists on the darker side of Western-centred modernity, living a life of wretchedness and continuing to suffer the colonial wound in the absence of formal colonialism and apartheid. The mineworker is disposable and dispensable and lives and works in the shadow of death. In pursuing this course of reasoning, I deploy the epistemic method of ‘shifting the geography of reason’ in order to read the experience of mineworkers in South Africa from the locus of enunciation of the oppressed subject within the scheme of a colonial power differential based on a hierarchy of humanity. This method allows me to speak with and from the perspective of the black mineworkers in the Platinum Belt as opposed to speaking for and about them. I reach the conclusion that being a platinum mineworker in post-apartheid South Africa is a racial and market determined identity of colonialised subjectivity that relegates the dominated subject (the black mineworker) to the realm of the subhuman. In setting the context for this claim, I trace the origins and development of the black mineworker in South Africa with reference to historical processes such as dispossession and proletarianisation. Empirically, the thesis is rooted in a contemporary case study of mainly Anglo Platinum Mine, which involved comprehensive fieldwork focusing on the present lived realities of platinum mineworkers. The dignity and humanity of these black mineworkers has still not returned despite twenty years of democratic rule in South Africa, such that race remains a crucial organising principle in postapartheid South Africa.
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Being civil
- Authors: Matshoba, Zongezile Theophilus
- Date: 2016
- Language: English , Xhosa
- Type: Thesis , Masters , MA
- Identifier: vital:6017 , http://hdl.handle.net/10962/d1021237
- Description: My collection of short stories delves into government and governance, democracy, citizenship, civil servants, poverty, corruption and nepotism. My stories draw on the traditions of gritty urban crime fiction uncovering crimes of violence, service delivery, vandalism and corruption. They explore themes of mental cruelty and greed, self- preservation and community in rural areas, farms, townships and cities characterized by wrenching contradictions and inequalities. , This epic dramatic poetic verse delves into government and school governance, labour unions, liberation struggle, parenting and a wide range of school perceptions. It interrogates the roles of parents, teachers, students, department of education officials and that of other stakeholders that make use of schools. Influenced by William Wellington Gqoba’s ‘A great debate on education: a Parable’ wayback, it continues the education debate in the current post-democratic South Africa characterized by wrenching contradictions and inequalities. , This thesis is presented in two parts: English and isiXhosa.
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Being for the Other: Surveillance and Depictions of Race, Gender, and Animals in Contemporary South African Fiction
- Authors: Laue, Kharys Ateh
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3848 , vital:20549
- Description: This thesis examines the depiction, in contemporary South African fiction, of irresponsibility and responsibility in relation to the raced, gendered, and animal Other. Through a close analysis of Jeremy Bentham’s Panopticon prison and Michel Foucault’s study of this design, I establish the notion of disciplinary surveillance or panopticism. This I take to be a mode of power that seeks, by means of an invisible gaze, to render its subjects docile. In my readings of J. M. Coetzee’s Waiting for the Barbarians, Zoë Wicomb’s Playing in the Light, Justin Cartwright’s White Lightning, and selected short stories from Wicomb’s You Can’t Get Lost in Cape Town and The One That Got Away, I demonstrate that oppressive authoritarian regimes are rooted in Benthamic principles of hyper-visibility and concealment. Disciplinary power, I contend, is effective precisely because it places an individual in a constant state of Being-for-Others, a term coined by Jean-Paul Sartre to describe the experience of objectification through another’s look. Judith Butler’s concept of gender performativity and W. E. B. Du Bois’s notion of black double consciousness frame my examination of, respectively, gender and racial oppression, while my discussion of animals appeals to Jacques Derrida’s work on the non-human. I show how surveillance, in each of the selected texts, functions through a racist and/or sexist and/or speciesist gaze that facilitates violent, irresponsible relationships with the human and non-human Other. The texts under discussion, however, also depict ways in which the Other actively resists and subverts regimes of oppression, often by means of a counter gaze that compels the protagonist, or the reader, to take up responsibility for Others. Ultimately, my study concludes that the fictional works of Coetzee, Wicomb, and Cartwright offer an ethics of empathetic responsibility, which I term Being for the Other, in opposition to mechanisms of disciplinary surveillance that seek to oppress, conceal, and dominate.
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Beta decay of 100/400 Zr produced in neutron-induced fission of natural uranium
- Authors: Kamoto, Thokozani
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3024 , vital:20353
- Description: Fission fragments, produced by neutron bombardment of natural uranium at the Physics Department, Jyväskylä, Finland, are studied in this work. The data had been sorted into 25 Y — y coincidence matrices which were then analysed. In this work we aimed to identify the fission products using Y-Y coincidence analysis and then study the beta-decay of some of the fission products. Sixteen fission products ranging from A = 94 to A = 136 were identified. Out of these fission products beta decay of the A = 100 (100/40 Zr – 100/41 Nb – 100/42 Mo) chain was studied in greater detail. We have also studied the variation of the relative intensities as a function of time of the 159-, 528-, 600-, 768-, 928- and 1502-keV Y-rav lines in 100/42 Mo and the profiles of the relative intensities have been modelled with the variation of the activity of 100/41 Nb against time. Configuration assignments of 100 Zr and 100/42 Mo are discussed.
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Between sentences
- Authors: Thesen, Jo-Ann
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:6007 , http://hdl.handle.net/10962/1021215
- Description: My stories explore different forms, including flash fiction. Some use the fairy tale form to combine fiction and non-fiction in order to reach the essence of the story. In this I am influenced by Kate Bernheimer, who speaks of the “flatness, abstraction, intuitive logic and normalized magic” of traditional fairy tales. A number of stories are set in the places I worked as a newspaper reporter. Here I use my old press reports as starting points for the real or imagined story behind the news – often involving miscommunication, dominance, exploitation, the tension between isolation and belonging, and the nuances of family relationships.
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Bio-prospecting a Soil Metagenomic Library for Carbohydrate Active Esterases
- Authors: Shezi, Ntombifuthi
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4172 , http://hdl.handle.net/10962/d1021266
- Description: Lignocellulosic biomass is a promising renewable resource on earth. Plant biomass contains fermentable sugars and other moieties that can be converted to biofuels or other chemicals. Enzymatic hydrolysis of these biopolymers is significant in the liberation of sugars for fermentation into desired products. Owing to its complex structure, synergistic action of enzymes is required for its degradation. Enzymes that are involved in biomass degradation include cellulases, hemicellulases and the accessory enzymes acetyl xylan esterases and ferulic acid esterases. Ferulic acid esterases (FAEs, EC 3.1.1.73), represent a subclass of carboxylester hydrolases (EC 3.1.1.-) that catalyse the release of hydroxycinnamic acids (such as ferulic acid, p-coumaric, ferulic, sinapic and caffeic acid) that are generally found esterified to polysaccharides, such as arabinoxylans. Hydroxycinnamic acids have widespread potential applications due to their antimicrobial, photoprotectant and antioxidant properties, as well as their use as flavour precursors. Therefore, this interesting group of FAEs has a potentially wide variety of applications in agriculture, food and pharmaceutical industries. In the search for novel biocatalysts, metagenomics is considered as an alternative approach to conventional microbe screening, therefore, searching for novel biocatalysts from a soil metagenome that harbours a unique diversity of biocatalyst is significant. The aim of this study was to extract DNA from soil associated with cattle manure and construct a soil metagenomic library using a fosmid based plasmid vector and subsequently functionally screen for ferulic acid esterases using ethyl ferulate as a model substrate. A total of 59 recombinant fosmids conferring ferulic acid esterase phenotypes were identified (Hit rate 1:3122) and the two fosmids that consistently showed high FAE activities were selected for further study. Following nucleotide sequencing and translational analysis, two fae encoding open reading frames (FAE9 and FAE27) of approximately 274 and 322 aa, respectively, were identified. The amino acid sequence of the two ORFs contained a classical conserved esterase/lipase G-x-S-x-G sequence motif. The two genes (fae9 and fae27) were successfully expressed in Escherichia coli BL21 (DE3) and the purified enzymes exhibited respective temperature optima of 50 °C and 40 °C, and respective pH optima of 6.0 and 7.0. Further biochemical characterisation showed that FAE9 and FAE27 have high substrate specificity, following the fact that EFA is the preferred substrate for FAE9 (kcat/Km value of 128 s−1.mM-1) and also the preferred substrate for FAE27 (kcat/Km value of 137 s−1.mM-1). This work proves that soil is a valuable environmental source for novel esterase screening through functional based metagenomic approach. Therefore, this method may be used to screen for other valuable enzymes from environmental sources using inexpensive natural sources to encourage the screening of specific enzymes. Biochemistry of the two isolated enzymes makes these enzymes to be useful in industrial applications due to broad substrate activity that could replace the specialised enzymes to complete plant biomass degradation.
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Biofuels and rural development: A case study of the Mapfura-Makhura Incubator and small-scale farmers in the Limpopo Province
- Authors: Mothupi, Frans Makwena
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/1488 , vital:20062
- Description: The primary objective of the study is to examine the livelihood impact of biofuel production on small-scale rural farmers participating in the MMI project in the local districts in Limpopo province. The study is theoretically underpinned by the sustainable livelihoods framework which provides a nuanced analysis of the complex nature of poverty and livelihoods. The framework was used to examine how MMI as a structure with its own processes (incubator model) plays a role in creating a means for farmers to have more access to livelihood assets which would help them achieve improved livelihoods outcome. The findings of this study reflect what has already been articulated in literature about small-scale biofuel projects. This study shows that MMI’s incubator plays an important role for 73% of the farmers to access all of the livelihood assets and ultimately improving their farm income and food security. Furthermore, 90% of the participants admitted to have received support from MMI in a number of ways. This includes the provision of farming inputs, labour and access to markets in addition to training, mentoring and coaching. The study also found that despite the overwhelming support, both MMI and farmers face a number of challenges. Farmers still lack adequate farming inputs, transport, access to markets and vulnerability to natural disasters. MMI faces challenges in raising funds to provide inputs to all their incubatees and lack of adequate mechanization. Lack of transportation affects both farmers and MMI in that farmers find it difficult to access MMI service. In the same light, MMI has found it difficult to reach farmers for post-incubation, coaching and mentoring or delivering inputs; this can be challenging and a costly process. MMI’s biofuel production project has the capability for improving rural livelihoods through agriculture. The study concludes by recommending that MMI should improve its own capacity in order for them to better the lives of the farmers they assist. This study is significant for contributing to a field which has received less academic and research attention in South Africa. Its scholarly contribution will enhance the existing body of knowledge on biofuels and rural development in South Africa
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Biology and ecology of Glossogobius callidus (Smith 1937) in irrigation impoundments in the Sundays River Valley of the Eastern Cape
- Authors: Mofu, Lubabalo
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/1136 , vital:20023
- Description: The River Goby Glossogobius callidus (Smith, 1937) is a native abundant fish in both freshwater and estuarine habitats in the Cape Fold Ecoregion, yet little information is available on its life-history. This study aims to contribute to knowledge on the age and growth, reproductive biology and the diet and feeding habits of G. callidus in irrigation impoundments. Glossogobius callidus was sampled monthly from August 2013 till March 2015; from the irrigation ponds in the Sundays River Valley, Eastern Cape Province, South Africa. To determine sex, gonads were visually assessed under a dissecting microscope to confirm the sex based on the shape of the urogenital papillae. Fish were then dissected to confirm sex and gonads were categorised into five macroscopic stages which were histologically validated. Microscopic stages of gonadal development were discerned based on nuclear and cytoplasmic characteristics of the oocyte or sperm. Ovaries and sperms were assigned stages based on the most advanced type of oocyte present. In total 2054 fishes ranging in length from 21.1 mm to 137.2 mm TL were sampled. The sex ratio (1.1 males: 1 females) did not differ from unity (x2 = 0.027, df = 1, p = 0.87). Length at 50% maturity (Lm) was 70 mm TL females and 72 mm TL for males. Spawning season was mid-spring and mid-summer and mean ± S.D absolute fecundity was estimated at 1028.2 ± 131.7 ova/fish. Relative fecundity (number of vitellogenic oocytes per gram of eviscerated fish mass) were estimated at 50 ± 18 ova/fish gram. Otoliths from 560 fish were used for ageing. Growth zone deposition rate was validated using edge analysis. As a unimodal periodic regression model best described the temporal proportion of opaque zone deposition on the edge of otoliths over a one-year period, growth zone deposition rate was validated as annual. The oldest female fish was a 4-year old 84.4 mm TL fish and the oldest male was a 7-year old 100.5 mm TL fish. The length-at-age for the entire population of 560 G. callidus provided von Bertalanffy parameters of Lt = 92 (1 - e -0.58(t + 0.4)) mm TL for the entire population, Lt = 70 (1 - e -1.8 (t + 0.06)) mm TL for males and Lt = 65 (1 - e -1.8 (t + 0.05)) mm TL for females. Converting length at maturity to age at maturity demonstrated that G. callidus attained maturity at an age of 2-years. Growth performance described using the phi-prime index showed that G. callidus had lower growth performance compared to the invasive Neogobius melanostomus. Using age structure, natural mortality was estimated at 1.31 yr-1 using catch curve analysis. Diet of G. callidus comprised of ten taxonomic groups. Among these, aquatic invertebrates were the most diverse group but while relative contribution of the dietary components varied across all size classes and seasons, the key prey items were consistently found in all size classes. These were Diptera, Hemiptera, Trichoptera, Odonata, Cladocera, Copepoda, Hydracarina, Amphipoda, Crustacea, and Mollusca. While dietary differences were observed between the size classes and throughout the seasons, G. callidus can be regarded as a generalist feeder preying on an array of different species. Given its abundance and diet, I suggest that G. callidus contribute considerably to the invertebrate predation pressure in these artificial aquatic environments in an arid region. In summary, medium fecundity, fast growth, moderate maturity, and a generalist feeding behaviour demonstrate that G. callidus is an equilibrium life strategist. In comparison with other species, the life-history traits of G. callidus from irrigation impoundments resemble those of other freshwater goby species, some of which are global invaders.
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Boetie is verlore: the reproduction of militarized white masculinities through the lens of Boetie gaan border toe! (1984)
- Authors: Coetzee, Joseph
- Date: 2016
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/4245 , vital:20638
- Description: My father fought for the South African Defence Force (SADF) from 1983 to 1985. At that time the apartheid regime was involved in extensive military operations in what is now Namibia and Angola. This conflict was aimed at quelling the liberation movements in those countries and, as Gary Baines has noted, supported the United States of America’s Cold War interests (Baines 2007:1). When I was fourteen I found a piece written by my father in which he remembers the first person that he had killed in the aforementioned conflict. This was a child soldier who he compared to me as I was a similar age at the time of his writing. The idea of my father as a killer haunted me. He has carried the trauma of his experiences on the border with him; he has told me how the dead visit him in dreams. On the one hand, these memories, not my own, have been constructed through my interpretation of the events in my father’s stories. On the other hand, homologies may be drawn between his actual experiences and a fantasy representation of the conflict I have encountered, the film Boetie gaan border toe! or Brother goes to the border! (1984). This apartheid propaganda film presents an idealised representation of the conflict from the point of view of the apartheid state. The protagonist of the film, Boetie, is an example of the aspirational and dominant image of militarised masculinity the apartheid state wished young white men to emulate. The racist sexist, patriarchal and materialistic reality created within the film is one I am familiar with. The toys I grew up playing with, television shows, films, advertising and popular culture I consumed, alongside the boys’ school I attended and the University I currently attend are all rooted in and continue to reproduce this reality. I have encountered many similar archetypes to the Boetie character. With this in mind I wish through my art practice to create a work which draws upon my father’s writing and imagery from Boetie gaan border toe! (1984). I have placed these alongside windows into my contemporary context in order to emphasise the continual reproduction of these ideas. In reference to the Boetie film I have decided to create my own film entitled Boetie is verlore or Brother is lost. This is a magic realist documentary film that I have constructed through various interviews and fantasy dream sequences in order to paint a picture of the continual incubation and reproduction of realities similar to that of Boetie. Boetie is a rich white man who is characterised through his material possessions and his compulsive heterosexuality. White women are interchangeable to him whilst blackness in the film is made completely invisible. In South Africa such representations are strongly linked to the question of land and naturalising the white male coloniser’s dominance and privilege.
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bones & flesh
- Authors: Hammerton, Kerry
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:6009 , http://hdl.handle.net/10962/d1021221
- Description: My collection encompasses personal relationships, intimacy, and the erotic, as well as more narrative poems grounded in landscapes, including urban and internal landscapes. Some were written in conversation with other poems or pieces of prose such as the stories of Noy Holland. I use free verse forms influenced by various prose poems as well as by the musical/tonal forms of poets such as Lorca. Other styles and influences include the darkness and directness of Spanish poetry particularly Rafael Alberti (esp. his book Concerning the Angels); and the confident and reflective style of Romanian poet Nina Cassian.
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Borderline hospitality: homestays as a commercial hospitality development project in Grahamstown, Eastern Cape
- Authors: Von Lengeling, Volkher Heinrich Christoph
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/706 , vital:19983
- Description: This study started as an anthropological investigation of commercial hospitality from the point of view of the hands-on host. The chosen case study for this investigation was the Kwam eMakana Government Initiated Poverty Alleviation Project which offered homestays in the townships of Grahamstown East since 2004. Homestays are the most intimate form of commercial hospitality, one step removed from non-commercial or social hospitality. Even at the homestay level there is a conceptual conflict between poverty and (Westernized) commercial hospitality, however, Kwam homes are more middle class than poor. Later the investigation revealed the deeper-seated form of poverty of the Kwam participants being (almost) illiterate. Kwam was a development project like many others, in which huge amounts of money were spent in the name of the project but very little of the benefits reached the intended beneficiaries. Thus, as fieldwork ensued, the emphasis of research migrated from an empirical study of homestay hospitality, to actively assist with the struggle of the Kwam hostesses to maintain the project and gain autonomy for themselves. This study was from the outset reflexive, as the host’s point of view could technically only be presented by auto-ethnography. Then the investigation shifted to a form of engaged anthropology far exceeding advocacy as it is usually understood. The presentation of this can be called radical reflexivity, while it is simultaneously an ethnographical account in the sense of anthropology ‘at home’. It also implied, besides ethical concerns, revisiting literary sensibilities, such as the use of a third person narrative for the reflexive account. To conceptualize the development process of both Kwam and the research interventions Bourdieu’s ‘totality of capital’ (in which the strands of economic, symbolic, cultural and social capitals intertwine) proved most useful. By assessing the various capitals the development of the project and the power struggles central to it can be understood. This study confirms that long-term anthropological investigation is best suited to the study of development projects, if not necessary for real development to be effected. Reflexivity and ethnography are complementary methods to reveal truths which under certain research circumstances may have been very difficult or even impossible to research.
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Calibration and wide field imaging with PAPER: a catalogue of compact sources
- Authors: Philip, Liju
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2397 , vital:20285
- Description: Observations of the redshifted 21 cm HI line promise to be a formidable tool for cosmology, allowing the investigation of the end of the so-called dark ages, when the first galaxies formed, and the subsequent Epoch of Reionization when the intergalactic medium transitioned from neutral to ionized. Such observations are plagued by foreground emission which is a few orders of magnitude brighter than the 21 cm line. In this thesis I analyzed data from the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) in order to improve the characterization of the extragalactic foreground component. I derived a catalogue of unresolved radio sources down to a 5 Jy flux density limit at 150 MHz and derived their spectral index distribution using literature data at 408 MHz. I implemented advanced techniques to calibrate radio interferometric data that led to a few percent accuracy on the flux density scale of the derived catalogue. This work, therefore, represents a further step towards creating an accurate, global sky model that is crucial to improve calibration of Epoch of Reionization observations.
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Changing planets and climates in select fantastic literature
- Authors: Ward, Brendan
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3994 , vital:20578
- Description: This thesis is concerned with literature’s engagement with the environment, specifically ecosystems and climate change. Literature of the fantastic, works that break from the tradition of mimetic literature and the limits of realism, are the focus of this thesis, which argues, alongside ecocriticism, that literature must be part of the interdisciplinary drive towards greater ecological awareness. Speculative literature adds fantastic elements or draws on scientific extrapolations into the future, and offers a platform to engage with the science of environmental issues alongside philosophical engagements with the relationship between humans and the more-than-human world around them. This thesis draws on ecocriticism to examine the role of reading and criticism in constructing more ecologically sustainable societies. From this position, it asks how fantasy can be used to convey these themes. As a result, this thesis is interested in definitions of fantasy, drawing on science fiction and fantasy to examine Kathryn Hume’s framework of the fantastic impulse. Placing fantastic texts on two axes, Hume examines the ways texts support or subvert the reader’s expectations, and encourage or discourage reflection on their extratextual worlds. This thesis contends that, texts that encourage engagement are most transformative, but that the spectrum of engagement and disengagement challenges authors to navigate between didacticism and emotive imagery. To show this, this thesis examines four series of novels drawing on the fantastic impulse. Frank Herbert’s Dune Chronicles, Kim Stanley Robinson’s Mars Trilogy and Science in the Capital, and George R.R. Martin’s A Song of Ice and Fire. The first two are on opposite ends of both of Hume’s axes, and imagine the challenges of constructing Earth-like ecosystems on other planets, asking questions about the sustainability of such a project as well as the possibilities of transforming society. The latter two engage with rapid climate change, Robinson’s looking at contemporary climate change and Martin’s engaging with historical climate change. They interrogate the impact of the climate on human and more- than-human life, and reveal the tension between comforting didactic revisions of human- environment interactions and framework-disturbing alternate ways of relating to the environment. This tension is where the fantastic is powerful, allowing alternate visions to pierce sceptical readers’ defences.
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Class actions as a means of enhancing access to justice in South Africa
- Authors: Marumo, Tladi
- Date: 2016
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3723 , http://hdl.handle.net/10962/d1021267
- Description: 21 years into democracy South Africa is marked by starkly contrasting experiences in the lives of its citizens. For some few, theirs remains a society defined by opulence and social, economic and political entitlements that accompany it. For a few beneficiaries, democracy has brought with it remarkable changes which have translated through their lives in economic, political and socialempowerment and wellbeing. Accompanying these changes has been the establishment and importantly, the enhancement of access to modern political and legal democratic and participatoryinstitutions of governance for these citizens. And yet, for the remaining majority of South Africans, their experience is marked by social and economic deprivation, poverty and vulnerability. These latter experiences are attributable to the historical legacy of colonialism and apartheid which continues to present itself in the form of persistent poverty and inequality in a ‘new South Africa.’ It is within this new South Africa, that this deprivation is further exacerbated by an increasingly unaccountable and unresponsive government ‘at war with its citizens.’ Service delivery protests, then have become a (if not the) way in which the poor and vulnerable get together as a collective, to try and take on the government in way they know how within their means, on deprivations of housing, electricity, water, sanitation, social assistance, healthcare and education. Finding an alternative legal means, whereby poor and vulnerable people themselves, may address these challenges is in the purpose of this thesis. However, the emphasis is not on addressing the plight of vulnerable groups through dependency from outside help, but on finding a means in which the agency (albeit constrained) of people to address their own concerns is recognised. The work investigates how law can enhance the collective agency of poor people to change their socioeconomic circumstances. In particular I investigate how the class action, a legal device which can enable people to come together collectively as a class in litigation for the enforcement of their rights of access to housing, electricity, water, sanitation, social assistance, healthcare and education, can achieve this. I provide recommendations on legal reform on how best access to courts can be made easier through the removal of barriers for impoverished communities to collectively enforce their socio-economic rights. I position the Regulation of Gatherings Act, a legislation which is aimed at affording legal protection to protest action, as a as accessible gateway into towards class litigation.
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Classical and quantum picture of the interior of two-dimensional black holes
- Authors: Shawa, Mark
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3629 , vital:20531
- Description: A quantum-mechanical description of black holes would represent the final step in our understanding of the nature of space-time. However, any progress towards that end is usually foiled by persistent space-time singularities that exist at the center of black holes. From the four-dimensional point of view, black holes seem to resist quantization. Under highly symmetric conditions, all higher-dimensional black holes are two-dimensional. Unlike their higher-dimensional counterparts, two dimensional black holes may not resist quantization. A non-trivial description of gravity in two dimensions is not possible using Einstein’s theory of gravity alone. However, we may still arrive at a consistent description of gravity by introducing a scalar field known as the dilaton. In this thesis, we study both the classical and quantum aspects of the interior of two-dimensional black holes using a generalized dilaton-gravity theory. Classically, we will find that the interior of most two-dimensional black holes is not much different from that of four-dimensional black holes. But by introducing quantized matter into the theory, the fluctuations in space-time will give a different picture of the structure of interior of black holes. Using a low-energy effective field theory, we will show that it is indeed possible to identify quantum modes in the interior of black holes and perform quantum-mechanical calculations near the singularity.
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