Redefining success : social justice and the ends of business
- Authors: Zorn, Gwendolyn Philippa
- Date: 2014
- Subjects: Success Social justice Success in business Social responsibility of business Business ethics Corporate profits
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2745 , http://hdl.handle.net/10962/d1012061
- Description: Success in business is for the most part defined in financial terms and, because of this, business operations are almost entirely, if not entirely, directed to this end. The principle behind this rationale has been informed by the thought that the best contribution businesses can make to social justice is to focus on the bottom line. By appealing to enlightened self-interest and the high premium people place on freedom, neoliberal economists like Milton Friedman and Friedrich Hayek argue that maximising profits is necessarily socially responsible. And, moreover, that not to pursue this end is socially irresponsible. Social responsibility is the ultimate justification that thinkers such as Friedman and Hayek appeal to when claiming that the business of business is to maximise profit. Yet this position is internally inconsistent. The position is ultimately justified by what is socially just but this means that in fact social justice, and not profit-making, ought to be the end of business. I shall argue that taking this commitment seriously involves rejecting the idea that the aim of business is to maximise profits. This is not to say that businesses should not make profits, rather it implies that this feature is not what ultimately makes them successful. The central contribution of this project is to resolve the contradictions embedded in the traditional approach to business by arguing that the primary aim of business is the promotion of social justice. To this end success in business needs to be redefined so that it reflects the achievement of its ultimate ends and not simply its instrumental means (profit) to the realisation of these aims. We ought then to revise our fundamental assumptions about the structures and policies that are necessary for business to achieve its real end of social justice.
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- Date Issued: 2014
Development and assessment of sustained release stavudine loaded microparticles
- Authors: Zindove, Chiedza Cathrine
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/54722 , vital:26603
- Description:
Stavudine (D4T) has been used as first line treatment for HIV/AIDS and is part of highly active anti retroviral treatment (HAART). It is an affordable medicine and its use is beneficial in resource limited settings. However D4T exhibits dose dependent side effects that may lead to non-adherence in patients. This study was undertaken to formulate, develop and manufacture a dosage form that could reduce dose dependent side effects by decreasing the dose of D4T but still exhibit antiretroviral (ARV) activity. The use of sustained release (SR) formulations of D4T that ensure constant levels of the D4T in the body would not only optimize therapy but also reduce the incidence of side effects thereby increasing patient adherence. SR microparticles containing 30mg D4T were manufactured and loaded into size 3 hard gelatine capsules prior to analysis. The D4T microparticles were manufactured by microencapsulation using non-aqueous oil-in-oil solvent evaporation approach. D4T-excipient, excipient-excipient interactions and D4T purity were assessed using Infrared Spectroscopy (IR), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Copolymers synthesized from acrylic and methacrylic acid esters viz., Eudragit® RSPO and S100 were used as rate retardant materials and the effect of microcrystalline cellulose (Avicel® PH102) on the microparticles was also investigated. Magnesium stearate was used as a droplet stabilizer and n-hexane was added to harden the microspheres formed in a liquid paraffin continuous phase. The microparticles were optimized using a Box Behnken design and Response Surface Methodology (RSM). The microparticles were characterized in terms of their flow properties and encapsulation efficiency (% EE), in addition to visualization of the surface morphology with Scanning Electron Microscopy. In vitro D4T release studies were performed using USP Apparatus III in media of different pH and the samples were analysed using a validated High Performance Liquid Chromatographic (HPLC) method with ultraviolet (UV) detection that had been developed and optimized using a Central Composite Design (CCD). The method was validated according to ICH guidelines. The IR spectra and DSC thermographs revealed that D4T exhibited thermal stability and there was no evidence of D4T-excipient and excipient-excipient interactions. The microparticles that were produced were white, free flowing and were obtained in a high yield with high encapsulation efficiency. Scanning Electron Microscopy studies revealed that the microparticles were spherical and porous in nature. In vitro D4T release extended to 12 hours and the mechanism of release was established using model dependent methods by fitting the data to a Zero order, First order, Higuchi and Hixson Crowell model. It was observed that the mechanism of D4T release was diffusion-controlled and that the data was best fitted to the Higuchi model with correlation coefficients > 0.9. The release mechanism was confirmed using the Korsmeyer-Peppas model that revealed that most of the formulations exhibited anomalous transport kinetics with the release exponent, n, ranging from 0.5
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- Date Issued: 2014
Synthesis of silver nanoparticles and their role against a thiazolekinase enzyme from Plasmodium falciparum
- Authors: Yao, Jia
- Date: 2014
- Subjects: Silver , Nanoparticles , Thiazoles , Plasmodium falciparum , Antimalarials , Malaria -- Chemotherapy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4168 , http://hdl.handle.net/10962/d1020894
- Description: Malaria, a mosquito-borne infectious disease, caused by the protozoan Plasmodium genus, is the greatest health challenges worldwide. The plasmodial vitamin B1 biosynthetic enzyme PfThzK diverges significantly, both structurally and functionally from its counterpart in higher eukaryotes, thereby making it particularly attractive as a biomedical target. In the present study, PfThzK was recombinantly produced as 6×His fusion protein in E. coli BL21, purified using nickel affinity chromatography and size exclusion chromatography resulting in 1.03% yield and specific activity 0.28 U/mg. The enzyme was found to be a monomer with a molecular mass of 34 kDa. Characterization of the PfThzK showed an optimum temperature and pH of 37°C and 7.5 respectively, and it is relatively stable (t₁/₂=2.66 h). Ag nanoparticles were synthesized by NaBH₄/tannic acid, and characterized by UV-vis spectroscopy and transmission electron microscopy. The morphologies of these Ag nanoparticles (in terms of size) synthesized by tannic acid appeared to be more controlled with the size of 7.06±2.41 nm, compared with those synthesized by NaBH₄, with the sized of 12.9±4.21 nm. The purified PfThzK was challenged with Ag NPs synthesized by tannic acid, and the results suggested that they competitively inhibited PfThzK (89 %) at low concentrations (5-10 μM) with a Ki = 6.45 μM.
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- Date Issued: 2014
The interface of history and fiction in Russel Brownlee’s Garden of the plagues, Ingrid Winterbach’s To hell With Cronjé, and Etienne van Heerden’s The long silence of Mario Salviati
- Authors: Wyrill, Beth Alexandra
- Date: 2014
- Subjects: Brownlee, Russel -- Criticism and interpretation , Winterbach, Ingrid -- Criticism and interpretation , Van Heerden, Etienne, 1954- -- Criticism and interpretation , South African fiction (English) -- History and criticism , South African fiction (English) -- 20th century -- History and criticism , African fiction (English) -- 21st century -- History and criticism , Brownlee, Russel -- Garden of the plagues , Winterbach, Ingrid -- Niggie -- English , Van Heerden, Etienne, 1954- -- Swye van Mario Salviati -- English , Historical fiction -- History and criticism , Magic realism (Literature)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2323 , http://hdl.handle.net/10962/d1015517
- Description: Both historiographical and literary practices have undergone revision in recent years in attempting to address the inheritance of nineteenth-century realism. Since the object of realist stylistics, employed in both the writing of fiction and history, is to render authorship authoritative or even invisible, the ideological import of these narratives is often such that the constructedness of the historical record and its absences are veiled. In developments beginning in the 1980s with the advent of ‘New Historicism’ and with the emergence of postmodern literary techniques, the interface of literature and history became of seminal importance, since both were now credited as being products of narrative and discourse, and hence, to varying degrees, of the literary imagination. This movement intersects interestingly with developments in postcolonial studies, since it is the voices of the marginalized and disempowered colonized peoples that are routinely co-opted and excised from nineteenth-century realist histories. These concerns are now being fully explored in the literature of the contemporary post-transitional South African moment, since authors in this country seemingly now feel freed up to look back to histories that precede the immediate traumas of apartheid. The concern, in relation to apartheid developments but also on a broader universal scale, is this: if history is viewed as perpetual emergences of modernities, then one of the great absences in the record is the historical determinants of any given epistemology. The attempt to recreate such an epistemological genealogy is thus simultaneously postcolonial, historiographical, and literary. Russel Brownlee’s Garden of the Plagues (2005), Ingrid Winterbach’s To Hell with Cronjé (2010), and Etienne van Heerden’s The Long Silence of Mario Salviati (2002) attempt to bridge this gap in the recorded sensibilities of any historical moment by representing a ‘lived experience’ of the past, and in the process imaginatively recreating the cultural, historical and psychological locations of the proponents of an emerging modernity. This study concerns itself with the ways in which these authors address the influence of realist historiography through the use of literary innovations that allow for the departure from realist stylistics. Most commonly, all three authors draw on forms of magic realism, but multiple refigurings and recombinations of notions of temporality, narrative, and characterization likewise work to defamiliarize the once stable discourse of history.
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- Date Issued: 2014
Taxonomy and life history of the zebra seabream, Diplodus cervinus (Perciformes: Sparidae), in southern Angola
- Authors: Winkler, Alexander Claus
- Date: 2014
- Subjects: Diplodus -- Classification Fish populations -- Angola Diplodus -- Angola Diplodus -- South Africa Diplodus -- Morphology Fisheries -- Angola Sparidae
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5361 , http://hdl.handle.net/10962/d1012062
- Description: The zebra sea bream, Diplodus cervinus (Sparidae) is an inshore fish comprised of two boreal subspecies from the Gulf of Oman and the Mediterranean / north eastern Atlantic and one austral subspecies from South Africa and southern Angola. The assumption of a single austral subspecies has, however, been questioned due to mounting molecular and morphological evidence suggesting that the cool Benguela current is a vicariant barrier that has separated many synonymous inshore fish species between South Africa and southern Angola. The aims of this thesis are to conduct a comparative morphological analysis of Diplodus cervinus in southern Angola and South Africa in order to classify the southern Angolan population and then to conduct a life history assessment to assess the life history impact of allopatry on this species between the two regions. Results of the morphological findings of the present study (ANOSIM, p < 0.05, Rmeristic = 0.42) and (Rmorphometric = 0.30) along with a concurrent molecular study (FST = 0.4 – 0.6), identified significant divergence between specimens from South Africa (n = 25) and southern Angola (n = 37) and supported stock separation and possibly sub-speciation, depending on the classification criteria utilised. While samples from the two boreal subspecies were not available for the comparative morphological or molecular analysis, comparisons of the colouration patterns between the three subspecies, suggested similarity between the southern Angola and the northern Atlantic / Mediterranean populations. In contrast, the colouration patterns between the southern Angolan and South African specimens differed substantially, further supporting the morphological and molecular results. The distinct morphological divergence between the southern Angolan and South African populations was not reflected within the life history traits of both populations. A combination of methods, including length/age frequency analyses, adult sex ratios and histological analysis was used to determine that this species is a rudimentary hermaphrodite in southern Angola. Peak spawning season was observed between June and July. The overall sex ratio (M: F) was 1:1.52 with females dominating smaller younger size classes and 50% maturity was attained at 210 mm FL and 4.6 years. Females [L(t) = 287.5(1-e⁻°·¹⁸⁽t⁻²·⁸⁴⁾)] grew significantly faster (LRT, p < 0.05) than males [L(t) = 380.19(1-e⁻°·°⁶⁽t⁻⁷·¹²⁾)]. The higher maximum age of the southern Angolan population of D. cervinus (43 years) was older than that of South African individuals sampled in the tsitsikamma national park. The similarities in the life history of the two austral populations are probably a consequence of similar selective pressures in the similar warmtemperate habitats. Evidence to support the above comments was found in the feeding study which showed that the South African and Angolan populations were almost identical, with both populations feeding primarily on amphipods and polychaete worms throughout ontogeny. In contrast, the diet of their boreal conspecifics from the Mediterranean was different, where larger individuals tended to select larger, and more robust, prey items. The life history differences observed between the boreal and austral populations can be attributed to either sampling bias or environmental factors. Sampling biases included the use of different age and growth estimation techniques, while the environmental factors would include differential selective pressures most likely driven by different resource availability and exploitation. The present study provides crucial baseline life history information of a potentially exploitable species off southern Angola as well as information on the life history plasticity of the species. Unfortunately, the current lack of uniformity in the methods used to estimate life history parameters between studies conducted on the boreal and austral populations have complicated our understanding of the evolution of various life history trends in sparid fish. From a management perspective however, the results from the present study can be used to propose management strategies for an emerging trap fishery in southern Angola. Using a balanced exploitation fishery approach (harvesting up to the size-at-100% maturity), the size of the fish traps entrance was calculated based the morphological information from this and other small sparid species that are targeted and was estimated to be 62 mm.
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- Date Issued: 2014
Towards the feasibility of a landowner enterprise in the western Baviaanskloof : an external stakeholder analysis
- Authors: Wiles, Kira Leigh Deborah
- Date: 2014
- Subjects: Landowners -- South Africa -- Eastern Cape , Natural resources -- Co-management -- South Africa -- Eastern Cape , Land use -- Environmental aspects -- South Africa -- Eastern Cape , Land use -- Economic aspects -- South Africa -- Eastern Cape , Partnership -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1198 , http://hdl.handle.net/10962/d1012075 , Landowners -- South Africa -- Eastern Cape , Natural resources -- Co-management -- South Africa -- Eastern Cape , Land use -- Environmental aspects -- South Africa -- Eastern Cape , Land use -- Economic aspects -- South Africa -- Eastern Cape , Partnership -- South Africa -- Eastern Cape
- Description: In May 2012, a meeting was held between various stakeholder representatives of the Western Baviaanskloof to discuss the concept of a proposed landowner-enterprise. This concept was put forward in response to a need for collaboration in the midst of economic, environmental and social issues at play in the Baviaanskloof. Owing to the conservation value and rapidly decreasing economic output of the land, a radical shift to sustainable land-use practices was called for by various stakeholders. Suggested as a vehicle to generate income for the local landowners through alternative sustainable land-uses, the proposed enterprise may aid in addressing this shift by use of a bottom-up approach. During the stakeholder meeting, it was requested by the representative landowners that a feasibility assessment be conducted on the concept of the proposed enterprise prior to establishment. As an integral part of this assessment, the researcher took on the task of investigating stakeholder reception to the enterprise by means of a stakeholder analysis. It was decided to limit this to three markets: water, carbon and tourism. The purpose of this research study is twofold, namely to: investigate stakeholder influence and their reception of the proposed enterprise using a stakeholder analysis; and also to identify and advise on the opportunities and constraints relating to stakeholders, thus contributing to determining the feasibility of the proposed enterprise. In achieving the purpose of this study, a systematic stakeholder analysis framework was constructed, based on existing theory. This was necessary because, although stakeholder analysis is commonly practiced, no study was found to provide a theoretically based framework for the purpose of feasibility in the initial stages of enterprise establishment. Thus the contribution of the study is also twofold, namely the practical outcome of determining stakeholder reception for feasibility, and a secondary outcome of constructing a stakeholder analysis framework. The stakeholder analysis framework is based on an interpretation of existing stakeholder theory, with the addition of four "relational indicators" – goals, intentions, relationships, and resources. These four indicators provide a link between theory and practice in gauging the two attributes of stakeholder influence – power and interest. Dealing with a number of stakeholder interests in a unique context, the study takes on a single network case study approach in the paradigm of phenomenology. To suit the complex nature of the study, semi-structured interviews with various stakeholder representatives were conducted, using groups or organisations as units of analysis. Drawing from the stakeholder analysis framework and overall purpose of the study, four research objectives were set. The first was to identify the proposed enterprise's legitimate key external stakeholders, based on the three markets: water, carbon and tourism; the second to describe, categorise and assess relative dyadic influence of the above stakeholders by gauging their power and interest; the third, to determine the stakeholder network influence and probable reception of the proposed enterprise; and the last to advise the landowners on any identified opportunities or constraints stakeholders might pose, and thus to contribute to determining feasibility. In addressing the first objective, 21 stakeholders were identified, 12 of whom were found to be key to the current investigation. These key stakeholders were: Gamtoos Irrigation Board (GIB), LivingLands, R3G, Rhodes Restoration Group, Eastern Cape Parks and Tourism Agency (ECPTA), Department of Water Affairs (DWA), Nelson Mandela Bay Metropolitan (NMBM), Saaimanshoek, South African National Biodiversity Institute (SANBI), Department of Economic Development, Environmental Affairs and Tourism (DEDEAT), Baviaans Tourism, and Baviaans Municipality. In applying the stakeholder analysis framework, ECPTA was categorised as the definitive (most influential) stakeholder to the enterprise, and DEDEAT, SANBI (through Working for Wetlands), Baviaans Tourism, GIB, and NMBM were categorised as pivotal (influential and active). In discerning stakeholder interest in the proposed enterprise, a number of emerging themes were found to affect the projected interest and behaviour of stakeholders, apart from their specified goals. Emerging themes included: tunnel visioning, internal disparity, individual/personality clashes, and misaligned interests. In addition to this, in interpreting stakeholder interest, specific intentions or agendas that might affect the interest shown towards the proposed enterprise were also taken into account. Five predominant intentions of stakeholders were identified as: implementing a stewardship programme, establishing a tourism association, establishing a water users' association, social development, and "the big vision". Findings on the final objective revealed a number of perceived opportunities and constraints relative to the feasibility of the enterprise. Three prime opportunities were identified as: partnerships with definitive and pivotal stakeholders, the possibility of tendering for implementer of the "Working for" programmes, and taking on the role of Tourism Association. The following potential constraints were also emphasised by participants: social aspects such as individuals and personalities, the incompatibility or non-existence of local market structures, and the need for external funding. With regard to stakeholder reception, most of the stakeholders, with the exception of NMBM and Saaimanshoek, responded positively to the idea of the enterprise. Overall, based on participant perceptions, the tourism market was found to be the most feasible the carbon market uncertain and a long-term possibility, and the water market the least feasible.
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- Date Issued: 2014
Factors influencing ecological sustainability in the ostrich industry in the Little Karoo, South Africa
- Authors: Wheeler, Anita
- Date: 2014
- Subjects: Ostrich farms -- South Africa -- Little Karoo , Land degradation -- South Africa -- Little Karoo , Land use -- South Africa -- Little Karoo , Land degradation -- Environmental aspects -- South Africa -- Little Karoo , Conservation of natural resources -- South Africa -- Little Karoo , Sustainable development -- South Africa -- Little Karoo , Sustainable agriculture -- South Africa -- Little Karoo
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4259 , http://hdl.handle.net/10962/d1011741 , Ostrich farms -- South Africa -- Little Karoo , Land degradation -- South Africa -- Little Karoo , Land use -- South Africa -- Little Karoo , Land degradation -- Environmental aspects -- South Africa -- Little Karoo , Conservation of natural resources -- South Africa -- Little Karoo , Sustainable development -- South Africa -- Little Karoo , Sustainable agriculture -- South Africa -- Little Karoo
- Description: The Little Karoo, situated in the Succulent Karoo biome of South Africa, has been heavily transformed by land use, and only 8.6% of the remaining natural vegetation is considered to be intact. There is ample evidence that the main cause of degradation is the overstocking of ostriches, an industry that has been the major economic driver of the area for more than 150 years. The ostrich stocking rate currently recommended is 22 ha.ostrich⁻¹. A literature review was used to examine the evidence, assumptions and rationale on which recommended and actually implemented stocking rates for ostriches are based. No experimental evidence using ostriches was found that supported the recommended stocking rate as either ecologically or economically sustainable. From the literature, there appears to be a wide gap between what are considered to be economically and ecologically sustainable stocking rates, with the implication that these two aims may be impossible to reconcile when practicing ostrich farming on natural veld. A comparison of recommended with actual stocking rates among land managers in the Little Karoo showed that all land managers far exceeded the recommended agricultural stocking rate of 22.8 ha.ostrich⁻¹. However, the stocking rates reported by land managers to the South African Ostrich Business Chamber were found to accurately reflect actual numbers determined when whole flocks had to be slaughtered after an outbreak of avian influenza. The recommended stocking rate appeared to be irrelevant to ostrich flock breeders and there appeared to be a trade-off between profitable ostrich farming and sustainable land-use practices. This study also investigated the attitudes and behaviour of ostrich farmers. It was found that environmental attitude is most likely the most important characteristic of a land manager to ensure positive conservation behaviour. This characteristic was most prominent in younger land managers with larger farms. The last component of the study integrated the context and complexity of the long term social, economic and ecological sustainability of this industry through the development of a logic model. The results showed a general lack of linkages between industry elements which impact on achieving sustainability targets. Greater collaboration between industry role-players, organized agriculture and conservation organizations is required to find a balance between utilization and conservation in the ostrich industry.
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- Date Issued: 2014
Linking satellite and point micrometeorological data to estimate : distributed evapotranspiration modelling based on MODIS LAI, Penman-Monteith and functional convergence theory
- Authors: Weideman, Craig Ivan
- Date: 2014
- Subjects: Plants -- Water requirements -- South Africa , Evaporation (Meteorology) -- Measurement , Satellite meteorology , Micrometeorology , Evapotranspiration , MODIS (Spectroradiometer)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4779 , http://hdl.handle.net/10962/d1012078 , Plants -- Water requirements -- South Africa , Evaporation (Meteorology) -- Measurement , Satellite meteorology , Micrometeorology , Evapotranspiration , MODIS (Spectroradiometer)
- Description: Recent advances in satellite sensor technology and micrometeorological instrumentation for water flux measurement, coupled with the expansion of automatic weather station networks that provide routine measurements of near-surface climate variables, present new opportunities for combining satellite and ground-based instrumentation to obtain distributed estimates of vegetation water use over wide areas in South Africa. In this study, a novel approach is tested, which uses satellite leaf area index (LAI) data retrieved by the Moderate Resolution Imaging Spectroradiometer (MODIS) to inform the FAO-56 Penman-Monteith equation for calculating reference evaporation (ET₀) of vegetation phenological activity. The model (ETMODIS) was validated at four sites in three different ecosystems across the country, including semi-arid savanna near Skukuza, mixed community grassland at Bellevue, near Pietermaritzburg, and Groenkop, a mixed evergreen indigenous forest near George, to determine potential for application over wider areas of the South African land surface towards meeting water resource management objectives. At Skukuza, evaluated against 170 days of flux data measured at a permanent eddy covariance (EC) flux tower in 2007, the model (ETMODIS) predicted 194.8 mm evapotranspiration relative to 148.9 mm measured fluxes, an overestimate of 31.7 %, (r² = 0.67). At an adjacent site, evaluated against flux data measured on two discrete periods of seven and eight days in February and May of 2005 using a large aperture scintillometer (SLS), ETMODIS predicted 27.4 mm and 6.7 mm evapotranspiration respectively, relative to measured fluxes of 32.5 and 8.2 mm, underestimates of 15.7 % and 18.3 % in each case (r² = 0.67 and 0.34, respectively). At Bellevue, evaluated against 235 days of evapotranspiration data measured using a surface layer scintillometer (SLS) in 2003, ETMODIS predicted 266.9 mm evapotranspiration relative to 460.2 mm measured fluxes, an underestimate of 42 % (r² = 0.67). At Groenkop, evaluated against data measured using a SLS over three discrete periods of four, seven and seven days in February, June and September/October respectively, ETMODIS predicted 9.7 mm, 10.3 mm and 17.0 mm evapotranspiration, relative to measured fluxes of 10.9 mm, 14.6 mm and 23. 9 mm, underestimates of 22.4 %, 11.2 % and 24.1 % in each case (r² = 0.98, 0.43 and 0.80, respectively). Total measured evapotranspiration exceeded total modelled evapotranspiration in all cases, with the exception of the flux tower site at Skukuza, where evapotranspiration was overestimated by ETMODIS by 31.7 % relative to measured (EC) values for the 170 days in 2007 where corresponding modelled and measured data were available. The most significant differences in measured versus predicted data were recorded at the Skukuza flux tower site in 2007 (31.7 % overestimate), and the Bellevue SLS flux site in 2003 (42 % underestimate); coefficients of determination, a measure of the extent to which modelled data are able to explain observed data at validation periods, with just two exceptions, were within a range of 0.67 – 0.98. Several sources of error and uncertainty were identified, relating predominantly to uncertainties in measured flux data used to evaluate ETMODIS, uncertainties in MODIS LAI submitted to ETMODIS, and uncertainties in ETMODIS itself, including model assumptions, and specific uncertainties relating to various inputs; further application of the model is required to test these uncertainties however, and establish confidence limits in performance. Nevertheless, the results of this study suggest that the technique is generally able to produce estimates of vegetation water use to within reasonably close approximations of measurements acquired using micrometeorological instruments, with r² values within the range of other peer-reviewed satellite remote sensing-based approaches.
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- Date Issued: 2014
A study exploring the relationship between employee happiness and financial performance within a South African financial institution
- Authors: Waugh, Geoffrey William
- Date: 2014
- Subjects: Financial institutions -- South Africa , Employee motivation , Financial institutions -- Ratings and rankings , Banks and banking -- South Africa , Bank employees -- South Africa , Job satisfaction
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:827 , http://hdl.handle.net/10962/d1012080
- Description: This research is an investigation of the relationship between employees 'happiness' and the financial performance of a financial services organisation in South Africa. As a component of the financial services industry the banking sector contributes greatly to the economic growth of the country. The South African Banking sector is concentrated and highly competitive. It is vital for banks to maintain competitiveness and ever increasing global competition adds further pressure on organisations to financially perform so as to meet the demands of their shareholders. The literature that has been reviewed and previous research suggest that employee 'happiness' is a vital variable influencing the performance and success of individuals. Organisational performance will be measured in terms of financial performance for the purposes of this research. The concept of financial performance and 'happiness' are discussed and a questionnaire based on the Satisfaction With Life Scale (Diener et al,1985) is used to determine the levels of 'happiness' at selected branches within the institution. The individual branches financial performance is determined via calculating selected ratios, namely cumulative leverage, cost to income ratio and net yield. An analysis of correlation was conducted to establish whether or not a relationship of statistical significance exists between employee 'happiness' and financial performance. It was concluded that there is no relationship of statistical significance between employee 'happiness' and the financial performance of branches within the organisation, it was suggested that other factors exert a much greater influence over financial performance. Some of these factors influencing financial performance are discussed and recommendations for further research are made.
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- Date Issued: 2014
Direct and indirect effects of zooplanktivorous predators on the estuarine plankton community
- Authors: Wasserman, Ryan John
- Date: 2014
- Subjects: Zooplankton -- Effect of predation on , Predation (Biology) , Zooplankton -- Predators of , Copepoda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5870 , http://hdl.handle.net/10962/d1012938
- Description: Although predation has been identified as a potentially important driver in terrestrial and freshwater ecosystems, estuarine planktonic research has focused largely on the so-called "bottom-up" drivers of community assemblages. As such, this thesis focuses on the direct and indirect effects of zooplanktivorous predators on the planktonic community in an estuarine environment. By using a suite of in situ mesocosm experiments, a number of hypotheses, pertaining to the major research themes associated with predator-prey interactions, are tested. These themes included trophic cascading, risk effects associated with predation events and the importance of predator diversity in maintaining prey communities. The first experiment assessed the significance of apex predation pressure for the planktonic community through trophic cascades. Various treatments using in situ mesocosms were established in a closed oligotrophic estuary to highlight the importance of predation in stabilising estuarine plankton abundances. Through either the removal (filtration) or addition of certain planktonic groups, varied trophic scenarios were established. The experimental treatment containing apex zooplanktivores had consequences for multiple trophic levels, exerting a stabilising pressure throughout the food web (Chapter 3). Furthermore, pyrosequencing of filtered water samples revealed that when compared to the remaining treatments, the treatment containing stable apex predatory pressure experienced limited temporal deviation-from-initial in bacterial community structure (Chapter 4). These findings are consistent with trophic cascade theory whereby predators mediate interactions at multiple lower trophic levels with consequent repercussions for diversity. To assess the non-consumptive effects of predators on prey, two experiments were conducted. Firstly, using egg numbers per clutch as a measure of potential reproductive output, the non-lethal effects of predatory pressure on reproductive success in a key planktonic copepod was investigated. In this study, the average clutch size of fecund female copepods was found to be consistently lower in the presence of predators when compared to females not exposed to predation threat (Chapter 5). The second study assessed the effects of conspecific chemical alarm cues associated with predation, on population dynamics of a copepod species. This study revealed that the copepods appear to detect the presence of chemical alarm cues associated with predation events, with repercussions for population demographics over time. Furthermore, it showed that in the absence of actual predation, copepod prey responses to alarm cues were adjusted over time, consistent with the threat sensitive predator avoidance hypothesis (Chapter 6). The final data chapter dealt with predator diversity and its implications for zooplankton community structure. By experimentally monitoring the effects of two alternate model predators on the metazoan community over time, dissimilarities in community level control emerged. Alternate key prey populations were regulated by the different model predators, highlighting the importance of predator and prey behaviour in mediating predator-prey interactions (Chapter 7). These results highlight the potential importance of predators in maintaining community dynamics in estuarine planktonic communities under certain conditions. This study represents some of the first work to address these various aspects of predator-prey dynamics within the context of planktonic estuarine ecology.
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- Date Issued: 2014
A psychobiographical study of Antwone Fisher
- Authors: Wannenburg, Nicola
- Date: 2014
- Subjects: Fisher, Antwone Quenton , Psychology -- Biographical methods , Psychoanalysis , Abused children -- Biography
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3219 , http://hdl.handle.net/10962/d1012939
- Description: Psychobiographical researchers methodically formulate life histories and interpret them by means of psychological theories. The research typically focuses on exemplary and completed lives. The cases that are studied are usually of individuals who are of particular interest to society as a result of excelling in their particular fields, be they to society’s benefit or detriment. Antwone Fisher was chosen for this study using purposive sampling as he meets the psychobiographical requirement of being an extraordinary individual. Fisher grew up in the Foster Care System and faced many abusive experiences as child. Despite difficult beginnings, Fisher developed into a stable and creative adult who excels as a poet, screenwriter and film director. The primary aim of this study is to describe and interpret the life of Antwone Fisher through Erikson’s theory of psychosocial development. The data was processed and analysed using Miles and Hubermans’ general view of qualitative analyses as well as Alexander’s method of asking the data questions. This study contributes to the development of psychobiographical research in South Africa as well as to personality and developmental theory.
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- Date Issued: 2014
An investigation into the bacterial diversity associated with South African latrunculid sponges that produce bioactive secondary metabolites
- Authors: Walmsley, Tara Aisling
- Date: 2014
- Subjects: Sponges -- South Africa -- Algoa Bay , Sponges -- Classification , Metabolites -- South Africa -- Algoa Bay , Marine metabolites -- South Africa -- Algoa Bay , PQQ (Biochemistry) , Bacterial diversity
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4109 , http://hdl.handle.net/10962/d1012943
- Description: Algoa Bay Latrunculid sponges are well known for their production of cytotoxic pyrroloiminoquinones with speculation that these secondary metabolites may have a microbial origin. This study describes a thorough investigation into the bacterial community associated with Tsitsikamma favus, Tsitsikamma scurra a newly described Latrunculia sp. and a yellow encrusting sponge associated with T. scurra. Molecular and chemical characterisation were used in conjunction with traditional taxonomy in identification of the sponge specimens. The 28S rRNA and COX1 analysis confirmed the traditional taxonomy with T. favus and T. scurra being very closely related. Chemical analysis revealed that T. favus and T. scurra shared the discorhabdins 2,4-debromo-3-dihydrodiscorhabdin C, 7,8-dehydro-3-dihydrodiscorhabdin C and 14-bromo-1-hydroxy-discorhabdin V in common with each other and Tsitsikamma pedunculata indicating that these pyrroloiminoquinones are common to Tsitsikamma sponges in general. The bacterial community associated with T. favus was explored using 16S rRNA molecular techniques including DGGE, clonal libraries of full length 16S rRNA genes, as well as 454 pyrosequencing. DGGE analysis revealed that the bacterial community associated with T. favus appeared to be highly conserved, which was confirmed by both the clone library and 454 pyrosequencing, with the Betaproteobacteria as the most dominant class. Further exploration into T. favus, as well as T. scurra, Latrunculia sp. and the yellow encrusting sponge indicated that the bacterial populations associated with each of these sponge species were conserved and species specific. OTU analysis to the species level revealed that T. favus and T. scurra shared an abundant Spirochaete species in common while the most abundant species in the Latrunculia sp. and the yellow encrusting sponge belonged to the class Betaproteobacteria. The exclusivity of the tsitsikammamines to T. favus precipitated attempts to culture the T. favus associated bacteria, with a focus on the dominant betaproteobacterium as indicated by the 16S rRNA clone library. Actinobacteria associated with the Algoa Bay sponge specimens were also cultured and the actinobacterial isolates were sent for screening against Mycobacterium aurum with two Kocuria kristinae isolates and a Streptomyces albdioflavus isolate showing good antimycobacterial activity.
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- Date Issued: 2014
South African International Relations (Ir) and the China-Africa relationship: a critical reflection
- Authors: Walker, Timothy Charles
- Date: 2014
- Subjects: South Africa -- Relations -- China , China -- Relations -- South Africa , International relations -- Philosophy , Critical theory
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2885 , http://hdl.handle.net/10962/d1015518
- Description: South African International Relations (IR) is a prominent source of China-Africa research and analysis, producing reports, journal articles and books that seek to illuminate the emerging relationship between China and Africa. It plays an important role in the framing of the relationship, as well as how it is perceived outside of the discipline. However, critical concerns have been raised about the context within which South African IR operates. It is therefore important that IR research, including its assumptions, dominant concepts, professed values and aspirations to studying the China-Africa relationship, be critically examined. The aim of this thesis is to contribute to critical thinking in South African IR by opening up for future discussion the new directions and possibilities for China-Africa IR. Utilising a critique located in Critical International Relations Theory (CIRT), this thesis critically reflects upon both the context of South African IR’s China-Africa research and the perspectives it has produced. The thesis argues that in spite of many descriptive and empirical studies, China- Africa research is theoretically underdeveloped in South African IR. Further, it argues that theoretical work is marginalised despite the fact that both historical and contemporary research relies on concepts drawn from IR theory. South African IR’s focus on policy relevance is advanced as a reason for the prevalence of theoretical underdevelopment. This thesis concludes by reviewing arguments for the improved use of IR theory in China-Africa IR, which will lead to a better understanding of this important relationship.
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- Date Issued: 2014
Dietary aspects of establishing a mainland-based colony of the endangered African Penguin (Spheniscus demersus) in St Francis Bay, South Africa
- Authors: Voogt, Nina Margaret
- Date: 2014
- Subjects: African penguin -- South Africa -- Cape Saint Francis , African penguin -- Food -- South Africa -- Algoa Bay , African penguin -- Habitat suitability index models -- South Africa -- Cape Saint Francis , Stable isotopes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5875 , http://hdl.handle.net/10962/d1013115
- Description: Cape St Francis, Eastern Cape, has been identified as one of four potential sites for establishing a mainland-based African penguin (Spheniscus demersus) colony. This thesis comprises three main components: a verification of a preparation method for stable isotope samples from penguin feathers; a dietary analysis of the penguins on Bird Island, Algoa Bay, though stable isotope analysis of whole blood and feathers (2012 and 2013); and an estimation of available fish surplus that could potentially support a colony of penguins at Cape St Francis. Each component contributes towards the next, all building towards answering the main research question: Will there be enough food around St Francis Bay to support a colony of penguins and sustain the already established fisheries industry within the bay? Stable isotope analysis of whole blood and feathers from breeding adults and whole blood from juveniles provided insight into the variability of African penguins’ diets at different stages in their life history. Stable isotope mixing models indicated that the predicted proportions that each prey species could potentially contribute to diet conflicted with published stomach sample data. This might arise from inaccurate trophic enrichment factors used in the model, or from systematic biases in the published stomach sampling techniques, or both. Dietary sexual dimorphism was not demonstrated by the isotope signatures of breeding penguins. Based on official catch data, the fisheries activity on the south coast, and especially around the potential colony site at St Francis, is much lower than around the west coast’s penguin colonies. The model provided a first-order estimate for fish supply around the potential colony site at St Francis both at a large coastal scale and a local small scale. At both scales the estimate indicated an ample availability of fish at current fishing levels. The model in Chapter 4 can also be applied to refining the assessments of other potential colony sites on the south coast. In conclusion, the south coast is a promising area for a new colony of penguins in terms of food availability. There is relatively low fishing activity in the area and, as suggested by the large-scale model in Chapter 4, an ample fish resource. The final chapter briefly discusses factors that need to be considered before attempting to establish a mainland-based colony of African penguins.
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- Date Issued: 2014
One leg at a time
- Authors: Vivier, Lincky Elmé
- Date: 2014
- Subjects: Creative writing (Higher education) -- Research -- South Africa , Creative writing -- Poetry , South African poetry (English) -- Study and teaching (Higher) , South African poetry (English) -- 21st century , English language -- Writing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5974 , http://hdl.handle.net/10962/d1012945
- Description: This collection of poems explores the boundaries between certainty and uncertainty, between the desire for meaning and the destabilisation of meaning. The content encompasses everyday life, love and loss, and the ambiguities are reflected in the forms used, so that, for instance, the linear continuity of narrative and the musicality of the lyric may be juxtaposed with the fragmented and imagistic leaps of the associative poem.
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- Date Issued: 2014
Strength training and cardiovascular risk post-menses, with particular emphasis on the plasma lipoproteins: a controlled trial
- Authors: Viljoen, Janet Erica
- Date: 2014
- Subjects: Weight training for women -- Physiological aspects , Exercise for women -- Physiological aspects , Middle-aged women -- Health and hygiene , Cardiovascular system -- Diseases , Hypercholesteremia , Blood lipoproteins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5155 , http://hdl.handle.net/10962/d1013578
- Description: Introduction: Cardiovascular disease affects a greater proportion of females than it does males, and is responsible for an estimated 52 percent of female deaths per annum, globally. Due to the loss of oestrogen associated with the menopause, post-menopausal females are at elevated risk for hypercholesterolaemia which is a primary risk factor for cardiovascular disease. It has not yet been conclusively established whether resistance training can be used to ameliorate hypercholesterolaemia. Aim: This randomized controlled trial investigated what effect 12 weeks of progressive resistance training would have on plasma lipoproteins in a sample of post-menopausal females. Methods: Caucasian women (n=30 intervention and n=18 control) between the ages of 55 and 65 years who were not taking hormone replacement therapy were recruited. Participants did not smoke, were sedentary, were not taking any form of cholesterol-lowering medication, had at least one cholesterol abnormality at baseline but were otherwise healthy and able to participate in a strength training programme. Following extensive medical pre-screening, information dissemination and voluntary consent, the sample was divided into two groups. The exercise sample undertook 12 weeks of resistance training on five days of the week. The control group received no intervention. Measurements were obtained at baseline and every four weeks thereafter and included measures of strength, biochemistry (oestradiol, testosterone, full blood lipid profile, glycated haemoglobin and sex hormone binding globulin), anthropometry, morphology and self-reports (dietary intake, energy expenditure and the profile of mood states questionnaire). Results: There was no change to low density lipoprotein cholesterol, high density lipoprotein cholesterol, triglyceride content or total cholesterol as a result of the intervention. Back, chest and leg strength increased significantly (p<0.01) (increases of 51 percent, 35 percent and 43 percent respectively from baseline); waist circumference dropped (p<0.01) by 5 percent overall and diastolic blood pressure decreased significantly (-9 percent, p<0.01) in the exercise cohort but no change was noted in the matched control. Dietary intake, energy expenditure and body mass remained unchanged in both samples. Morphology (sum of skinfolds, estimated body fat content and girth measures) did not change and nor did other biochemical measures (HbA1c and sex hormone binding globulin) or hormone levels (oestradiol and testosterone). Despite the lack of overall change, an important finding was noted in individual results where a clear indication of ‘responders’ and ‘non-responders’ emerged. Conclusion: Overall mean results suggest that 12 weeks resistance training undertaken five days of the week was ineffective in reducing hypercholesterolaemia in this sample. Despite there being no identifying characteristics determined in this sample, evidence of responders and non-responders to the intervention indicates that reliance on mean data may not be sufficient when analysing data from exercise interventions. Therefore, while progressive resistance training had a positive effect on strength, waist circumference and diastolic blood pressure, it did not positively influence the plasma lipoproteins in this cohort of post-menopausal women. , Maiden name: Kelly, Janet Erica
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- Date Issued: 2014
Synthetic analogues of marine bisindole alkaloids as potent selective inhibitors of MRSA pyruvate kinase
- Authors: Veale, Clinton Gareth Lancaster
- Date: 2014 , 2014-04-02
- Subjects: Alkaloids , Pyruvate kinase , Staphylococcus aureus , Antibiotics , Sponges -- South Africa , Imidazoles , Biological assay , Antibacterial agents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4563 , http://hdl.handle.net/10962/d1020893
- Description: Globally, methicillin resistant Staphylococcus aureus (MRSA) has become increasingly difficult to manage in the clinic and new antibiotics are required. The structure activity relationship (SAR) study presented in this thesis forms part of an international collaborative effort to identify potent and selective inhibitors of an MRSA pyruvate kinase (PK) enzyme target. In earlier work the known marine natural product bromodeoxytopsentin (1.6), isolated from a South African marine sponge Topsentia pachastrelloides, exhibited selective and significant inhibition of MRSA PK (IC₅₀ 60 nM). Accordingly bromodeoxytopsentin provided the initial chemical scaffold around which our SAR study was developed. Following a comprehensive introduction, providing the necessary background to the research described in subsequent Chapters, this thesis has been divided into three major parts. Part one (Chapter 2) documents the synthesis of two natural imidazole containing topsentin analogues 1.40, 1.46, five new synthetic analogues 1.58—1.61, 2.104. In the process we developed a new method for the synthesis of topsentin derivatives via selenium dioxide mediated oxidation of N-Boc protected 3-acetylindoles to yield glyoxal intermediates which were subsequently cyclized and deprotected to yield the desired products. Interestingly we were able to demonstrate a delicate relationship between the relative equivalents of selenium dioxide and water used during the oxidation step, careful manipulation of which was required to prevent the uncontrolled formation of side products. Synthetic compounds 1.40, 1.46, 1.58—1.61 were found to be potent inhibitors of MRSA PK (IC₅₀ 238, 2.1, 23, 1.4, 6.3 and 3.2 nM respectively) with 1000-10000 fold selectivity for MRSA PK over four human orthologs. In the second part of this thesis (Chapter 3) we report the successful synthesis of a cohort of previously unknown thiazole containing bisindole topsentin analogues 1.62—1.68 via a Hantzsch thiazole synthesis. Bioassay results revealed that these compounds were only moderate inhibitors of MRSA PK (IC₅₀ 5.1—20 μM) which suggested that inhibitory activity was significantly reduced upon substitution of the central imidazole ring of topsentin type analogues with a thiazole type ring. In addition in Chapter 3 we describe unsuccessful attempts to regiospecifically synthesize oxazole and imidazole topsentin analogues through a similar Hantzsch method. As a consequence of our efforts in this regard we investigated three key reactions in depth, namely the synthesis of 2.2, 3.38, 3.40, 3.41 via α-bromination of 3-acetylindole and the synthesis of indolyl-3-carbonylnitriles 2.13, 3.45—3.47 and α-oxo-1H-indole-3-thioacetamides 3.48—3.51. The investigation of the latter led to the isolation and elucidation of two anomalous N,N-dimethyl-1H-indole-3-carboxamides 3.52 and 3.53. Finally the third part of this thesis (Chapter 4) deals with in silico assessment of the binding of both the imidazole and thiazole containing bisindole alkaloids to the MRSA PK protein which initially guided our SAR studies. In this chapter we reveal that there appears to be no correlation between in silico binding predictions and in vitro MRSA PK inhibitory bioassay data. Superficially it seems that binding energy as determined by the docking program used for these studies correlated with the size of the indole substituents and did not reflect IC₅₀ MRSA PK inhibitory data. Although this led us to computationally explore possible alternative binding sites no clear alternative has been identified.
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- Date Issued: 2014
Undertaking to care and to protect : The experience of killing healthy homeless animals in South Africa
- Authors: Van Zyl, Henriette Louise
- Date: 2014
- Subjects: Animal welfare -- Moral and ethical aspects -- South Africa , Euthanasia of animals -- South Africa , Euthanasia of animals -- Psychological aspects , Human-animal relationships -- South Africa , Animal rights -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3245 , http://hdl.handle.net/10962/d1013577
- Description: Although animal welfare workers overwhelmingly describe themselves as animal lovers the exigencies of day to day animal welfare work often require that they perform euthanasia of healthy animals as part of welfare shelter management, and animal population control. In this research study, the particular burdens placed upon seven South Animal welfare workers who are required to rescue, care for, nurture and rehabilitate the animals in their care; while simultaneously being required to kill these same – often physically and behaviourally healthy - animals after a specific period of time, or in response to various logistical, procedural and practical intricacies, ranging from lack of space and resources to an unavailability of suitable homes; are explored from an interpretative phenomenological approach using the Interpretative Phenomenological Method (IPA), and from a South African perspective. It was found that animal-loving individuals engaged in the care and subsequent euthanasia of healthy animals report experiencing profound personal, interpersonal and professional and ideological (dis)stress related to guilt, sorrow, moral unease and horror. Four themes emerged from interview data, which are discussed in relation to relevant research and literature. Experiences in a South African context were found to be very much aligned with those reported in previous research and literature pertaining to this topic. In particular, it was found that there is a need to articulate specifically, and precisely the nature of the act. It is proposed that the term “Agapéthanasia” would be appropriate and useful in this field.
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- Date Issued: 2014
A formalised ontology for network attack classification
- Authors: Van Heerden, Renier Pelser
- Date: 2014
- Subjects: Computer networks -- Security measures Computer security Computer crimes -- Investigation Computer crimes -- Prevention
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4691 , http://hdl.handle.net/10962/d1011603
- Description: One of the most popular attack vectors against computers are their network connections. Attacks on computers through their networks are commonplace and have various levels of complexity. This research formally describes network-based computer attacks in the form of a story, formally and within an ontology. The ontology categorises network attacks where attack scenarios are the focal class. This class consists of: Denial-of- Service, Industrial Espionage, Web Defacement, Unauthorised Data Access, Financial Theft, Industrial Sabotage, Cyber-Warfare, Resource Theft, System Compromise, and Runaway Malware. This ontology was developed by building a taxonomy and a temporal network attack model. Network attack instances (also know as individuals) are classified according to their respective attack scenarios, with the use of an automated reasoner within the ontology. The automated reasoner deductions are verified formally; and via the automated reasoner, a relaxed set of scenarios is determined, which is relevant in a near real-time environment. A prototype system (called Aeneas) was developed to classify network-based attacks. Aeneas integrates the sensors into a detection system that can classify network attacks in a near real-time environment. To verify the ontology and the prototype Aeneas, a virtual test bed was developed in which network-based attacks were generated to verify the detection system. Aeneas was able to detect incoming attacks and classify them according to their scenario. The novel part of this research is the attack scenarios that are described in the form of a story, as well as formally and in an ontology. The ontology is used in a novel way to determine to which class attack instances belong and how the network attack ontology is affected in a near real-time environment.
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- Date Issued: 2014
Prioritising native fish populations for conservation using genetics in the Groot Marico catchment, North West Province, South Africa
- Authors: Van der Walt, Kerry-Ann
- Date: 2014
- Subjects: Native fishes Fishery management -- South Africa -- North West Fish populations Fishes -- Conservation -- South Africa -- Western Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/69102 , vital:29390
- Description: The Groot Marico catchment in the North West Province is a National Freshwater Ecosystem Priority Area (NFEPA) because it represents unique landscape features with unique biodiversity that are considered to be of special ecological significance. Three native freshwater species Amphilius uranoscopus, Chiloglanis pretoriae and Barbus motebensis, have high local conservation importance and B. motebensis is endemic to the catchment and is IUCN-listed as vulnerable. The main objective of this study is to contribute towards the effective conservation of these three species in the Groot Marico River system by assessing their genetic structure to determine whether tributary populations of the three species comprise of one genetic population or whether they are divided into genetically distinct subpopulations, in order to prioritise areas for conservation. The central null hypothesis was that there is no genetic differentiation between tributary populations (i.e., panmixia) of B. motebensis, A. uranoscopus and C. pretoriae in the Groot Marico catchment, North West Province. In total, 80 individuals per species were collected, targeting at least 10 individuals per population from a total of eight populations (seven tributaries and the Groot Marico main stem) and across the study area. Samples were collected by electrofishing and specimens were euthanized using an overdose of clove oil. A sample of muscle tissue was removed for genetic evaluation and the remainder of the specimens served as voucher specimens. For the genetic evaluation, mitochondrial (ND2, cyt b) and nuclear (S7) genes were used. Genetic techniques used were DNA extraction, polymerase chain reaction (PCR), purification and sequencing. From the 240 individuals collected, 123 sequences for B. motebensis, 111 sequences for A. uranoscopus and 103 sequences for C. pretoriae were analysed across all three genes. Statistical analysis included looking at cleaned sequences in order to obtain models using MODELTEST (version 3.06). Population structuring and phylogeographic analysis was performed in Arlequin (version 2000), TCS (version 1.2.1) and PAUP*. Results indicated that for B. motebensis the null hypothesis could be rejected as there were two distinct lineages (the Draai and Eastern lineages) that demonstrated significant divergence in both the ND2 and S7 genes, suggesting historical isolation. The low divergence in the mitochondrial cytochrome b gene (0% < D < 0.8%) suggests that this isolation is not very old and is probably not comparable to species level differentiation. The null hypothesis was also rejected for A. uranoscopus as there were also significant levels of differentiation between tributary populations resulting in the identification of two lineages (the Ribbok and Western lineages). However, for C. pretoriae, the null hypothesis could not be rejected as there was no genetic differentiation between tributary populations i.e., one panmictic population. Therefore, due to each species showing different genetic structuring within the tributary populations, more than one priority area for conservation needs to be implemented. These priority areas of conservation where therefore evaluated based on the current conservation status of the species (B. motebensis being vulnerable on the IUCN Red List), the number of Evolutionary Significant Units for each species and the overall genetic diversity of all three species in the Groot Marico catchment. In total, four tributary populations were conservation priorities areas, these were the Draai, Vanstraatens, Ribbok and Kaaloog tributaries. The Draai, Vanstraatens and Kaaloog tributaries were selected as priority areas for B. motebensis (B. motebensis is considered to be the most vulnerable of all three species). The Draai tributary was selected due to the B. motebensis population within the tributary showing isolation from the rest of the tributary populations. In order to conserve B. motebensis from the Southern lineage, the Vanstraatens and Kaaloog tributaries were selected. Reasons for selecting these two specific tributaries within the Southern lineage were that the Vanstraatens tributary had unique alleles (three Evolutionary Significant Units) for B. motebensis and the Kaaloog tributary had high genetic diversity (HD = 0.889, ND2 gene) when compared to the other tributary populations. The Ribbok and Vanstraatens tributaries were selected as priority areas for the conservation of A. uranoscopus. The Ribbok tributary was selected as it showed isolation from the rest of the tributary populations, as seen with the Draai tributary (B. motebensis) and the Vanstraatens tributary was selected to represent the Western lineage as it had the highest diversity for both genes (ND2 and S7). The Ribbok tributary has the highest prioritisation when compared to the Vanstraatens tributary. Chiloglanis pretoriae occurs within the Draai, Vanstraatens, Ribbok and Kaaloog tributaries, therefore by prioritising these tributaries for conservation, C. pretoriae will in turn be conserved.
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- Date Issued: 2014