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Megaherbivores in succulent thicket: resource use and implications

  • Authors: Landman, Marietjie
  • Date: 2012
  • Subjects: Elephants , African elephant , Black rhinoceros , Succulent plants
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:10689 , http://hdl.handle.net/10948/d1007956 , Elephants , African elephant , Black rhinoceros , Succulent plants
  • Description: This study aims to develop a predictive understanding of the resource use, impacts and interactions of elephant Loxodonta africana and black rhinoceros Diceros bicornis in the succulent thickets of the Eastern Cape, South Africa. While these megaherbivores typically dominate the biomass, elephant are more abundant, such that their impacts off-set that of all other herbivores. Consequently, this thesis has three main foci: first, developing a mechanistic understanding of the influences of elephant; second, developing predictive insights into elephant impacts on plant communities; finally, an understanding of the knockon-effects of the impacts for coexisting rhinoceros. Thus, by documenting the diet and dietary preferences of elephant, I firstly show that only about 18 percent of the species previously thought vulnerable to herbivory, occur in the diet. This refutes the generally held belief that elephant herbivory is the primary driver of decline among plants, and emphasizes the likely contribution of other mechanisms (e.g. trampling, knock-on-effects, etc.). Thus, the accurate prediction of the impacts caused by elephant requires an understanding of previously marginalized mechanisms. From here, I quantify >50 years of impacts on the thicket shrub community and test their spatial and temporal extent near water. I confirm the vulnerability of thicket to transformation (particularly near water) as the accumulated influences of elephant reduce community composition and structure, and predict that these impacts will eventually bring about landscape-level degradation and a significant loss of biodiversity. Importantly, results show an uneven distribution of effects between elements of this community: from community composition and structure, to the structure of individual canopy species and ecological functioning. While these findings confound our interpretation of the extent of the impacts, it demonstrates the importance of explicitly recognizing biodiversity and heterogeneity for the conservation management of elephant. Finally, I test the consequences of the impacts for coexisting rhinoceros. While I show that this causes rhinoceros to change their foraging strategies in the presence of elephant at high densities, I also show that elephant may facilitate access to food for rhinoceros at reduced densities. These findings indicate the importance of elephant in driving the structure and composition of the thicket shrub community and the consequences of this for coexisting large herbivores. Thus, developing a predictive understanding of the spatial and temporal variations of elephant impacts between elements of biodiversity and the mechanisms driving these changes are key to their management. This implies that the effective conservation management of elephant can only be achieved through the careful, scientific design of monitoring programmes.
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  • Date Issued: 2012

Mercosur-SACU relations : an examination of the revised economic initiative for South-South Cooperation

  • Authors: Mpepho, Lwandiso Arthur
  • Date: 2012
  • Subjects: Developing countries -- Economic policy , Customs unions , Sustainable development
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:8326 , http://hdl.handle.net/10948/d1020348
  • Description: The study was conducted to examine economic relations between the Southern African Customs Union (SACU) and the Mercado Commun del Sur (translated Southern Common Market), in short (Mercosur). SACU was established in 1910 and consists of five member countries, namely; South Africa, Botswana, Lesotho, Namibia and Swaziland. Mercosur was created in 1991 and consists of Argentina, Brazil, Paraguay and Uruguay, with Bolivia, Chile, Colombia, Ecuador, Peru and Venezuela being associate members. The aim of the study was to ascertain whether the Mercosur-SACU relations had created more economic opportunities for both regions. In pursuit of this aim, the study revised and analysed the evolution, development and growth of both Mercosur and SACU. It also analysed the achievements and challenges faced by each of the blocs in their respective regions. The conclusion of the analysis indicate that, countries which were economically stronger before the establishment of formal bloc-to-bloc relations, Brazil in Mercosur and South Africa in SACU, tended to reap disproportionally high dividends than others. The study further concludes that challenges facing Mercosur and SACU countries should not discourage them in pursuing collective developmental initiatives such as regional integration and South-South Cooperation.
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  • Date Issued: 2012

Mesozooplankton dynamics in a biogeographical transition zone estuary

  • Authors: Deyzel, (Shaun) Herklaas Phillipus
  • Date: 2012
  • Subjects: Marine zooplankton -- South Africa , Benthos -- South Africa , Estuarine ecology -- South Africa , Mangrove forests
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:10687 , http://hdl.handle.net/10948/d1007901 , Marine zooplankton -- South Africa , Benthos -- South Africa , Estuarine ecology -- South Africa , Mangrove forests
  • Description: This thesis presents the first intensive community-level investigation of the mesozooplankton from a biogeographical transition zone estuary. The Mgazana Estuary is located along a rural, semi-undeveloped part of South Africa’s east coast, believed to represent a transition zone between the subtropical and warm-temperate biogeographical zones. The research represented in this thesis involves data collected over a five year period between 2002 and 2006, with additional data collection made in 2008. The study focussed on five areas of investigation, the first of which investigated the physico-chemical dynamics of the Mgazana Estuary. The Mgazana Estuary exhibited marked vertical, horizontal and regional structures in the hydrological environment. Prominent vertical and horizontal stratification characterised summer months. A substantial turbidity front was observed in the lower estuary during summer and winter. The upper estuary was marked by considerable variation in multiple variables but especially salinity. These structures appeared to have shifted in position over the horizontal plane, which was attributed to variation in freshwater flow. The second study focused on the spatial dynamics of mesozooplankton in the Mgazana Estuary. The zooplankton was rich and in terms of composition typical of mangrove systems. The Copepoda were dominant, numerically and in terms of taxonomic representation. Calanoids Acartiella natalensis and Pseudodiaptomus hessei characterised middle and upper reaches in summer and mostly upper reaches in winter. On community level, a highly structured assemblage arrangement was observed during summer and winter months. These trends were further scrutinised under the theoretical framework of ecological boundaries. In so doing, an agreeable spatial association emerged between specific assemblages and their environments. These trends were concluded to reflect ecoclinal as well as ecotonal properties, the latter describing interactions over narrow spatial bands of marked changes in turbidity. The third study investigated flooding events as short-lived extreme meteorological events and the influence on zooplankton. Within this regard, second-stage multivariate statistics was used to assess year-to-year variability in assemblage structures on whole-system and regional scales. The impact of two major flooding events that flushed the estuary some days prior to sampling could clearly be elucidated. Flooding emerged as a significant source of inter-annual variability in the zooplankton of the Mgazana Estuary. Second-stage multivariate analysis proved to be an effective analytical strategy for investigating inter-annual variability in species assemblage structures. Results from the preceding study prompted a detailed investigation into the spatio-temporal dynamics of Acartiella natalensis, the most important zooplankton species of the system aimed at elucidating flood responses. Acartiella natalensis showed indication of temporal arrest in association with flooding events in a similar fashion as is observed in seasonal variation trends in estuaries towards its geographical distribution limit south of the study area. It was concluded that A. natalensis was severely affected by floods and the possibility exist for entrainment of entire populations from the estuary during flooding events. The final study tested the hypothesis of post-flood propagation from a resting egg bank in the sediments of the Mgazana Estuary. Preliminary data revealed that numerous eggs were present in the sediments. Nauplii hatched from eggs under laboratory conditions were identified as belonging to the family Acartiidae. The preliminary mode of diapause is presented as a schematic model, emphasising the role of freshwater flow and specific environmental variables. This was the first discovery of resting eggs from a subtropical estuary from South Africa. It is hoped that the findings of this study would give rise to new research initiatives investigating the importance of resting stages in estuarine and coastal Copepoda species and the role such reproductive strategies may play in estuarine functioning.
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  • Date Issued: 2012

Microalgae and macrophytes as indicators of ecological health in the Great Brak Estuary

  • Authors: Nunes, Monique
  • Date: 2012
  • Subjects: Microalge -- South Africa -- Great Brak Estuary , Estuarine ecology -- South Africa , Aquatic plants -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10629 , http://hdl.handle.net/10948/d1012097 , Microalge -- South Africa -- Great Brak Estuary , Estuarine ecology -- South Africa , Aquatic plants -- South Africa
  • Description: The Great Brak temporarily open/closed estuary was subjected to a drought during the spring and summer of 2009/2010 resulting in the mouth remaining closed for a prolonged period. According to the Great Brak Estuary management programme, the mouth of the estuary had to be open for a total of 308 days during spring and summer of 2009/2010, respectively, but was closed for almost the entire two years (693 days). The aim of this study was to assess monthly changes in the abiotic characteristics (salinity, temperature, oxygen, pH and nutrients) and the biotic responses of phytoplankton and macroalgae; identify sources of nutrient input into the estuary and determine the response of the salt marsh to water level and salinity changes. The results indicated that physico-chemical parameters were similar to that previously recorded during the closed mouth condition. However mouth closure combined with elevated nutrient concentrations led to a shift from rooted submerged macrophytes to one where either microalgae or macroalgae were dominant. Soluble reactive phosphorus concentrations were significantly higher in bottom compared with surface waters. There was a significant negative correlation with SRP and dissolved oxygen for the sampling period indicating potential release of phosphorus from the sediment during closed mouth conditions. Microalgal biomass increased in response to remineralised nutrients and freshwater pulses. Flagellates were the dominant microalgal group (21718 ± 3336 cells m l-1, p < 0.05) because of their morphological ability to migrate vertically within the water column. The macroalgal cover was highest during the closed mouth state but only during winter (August 2010) when temperatures were below 20 oC. Five major point sources of nutrient input into the Great Brak Estuary were identified during rainfall periods. Point sources 4 and 5 in the upper reaches of the estuary had the highest DIN input whereas point source 3 in the middle reaches of the estuary had the highest DIP input. As a result of the drought and low water level, the salt marsh was never inundated for longer than 3 months. Die-back of Sarcocornia decumbens (r 2= -0.62, p < 0.05) was related to smothering by dead macroalgae whereas dieback of Sporobolus virginicus was related to decreasing nutrient (r2 = 0.59, p < 0.05) and salinity (r2 = 0.55, p < 0.05) levels. The physico-chemical characteristics alone did not convey the true health status of the Great Brak Estuary for the duration of the sampling (April 2010-April 2011). The study showed that microalgae and macroalgae are valuable indicators of the status of the estuary. Therefore it is suggested that bio-indicators are incorporated into the management/monitoring plan in order to assist in improving the health assessment of the Great Brak Estuary.
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  • Date Issued: 2012

Microalgae biomass as fermentation feedstock

  • Authors: Tijjani-Oshungboye, Kubura
  • Date: 2012
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5956 , http://hdl.handle.net/10962/d1006168
  • Description: The search for alternative energy is as a result of pollution generated by the utilization of fossil fuel. Bearing in mind the increase in demand which exceeds supply, alternative energy must reduce the carbon foot print in order to relieve use of fossil fuels. Biogas generation from wastes is an old technology that has been in existence for decades. This same concept was behind the development of the integrated algae ponding system (IAPS), where the use of microalgae biomass is adopted for waste water treatment and, anaerobic digestion which is a component of the IAPS, simultaneously generates biogas. The biogas from the IAPS was quantified in order to evaluate efficiency of the system and the anaerobic fermentation pit was also simulated in the laboratory to optimize biogas production using microalgae as co-fermentation feedstock. Microalgae biomass was evaluated as potential feedstock for ethanol fermentation and the use of biogas was investigated as an alternative transportation fuel. In an IAPS substantial biomass is produced on an annual basis. For effective treatment of waste water and efficient nutrient removal continuous harvest of the biomass is required. In the present study, water treatment efficiency of the EBRU IAPS was determined by carrying out a series of tests to investigate the decline in nutrient content from port of influent entry to effluent discharge. There was more than a 60% reduction in nutrient content with a concomitant increase in biomass and growth rate of 0.25 g/L . Biogas generated from the IAPS was quantified using a flow meter and the composition determined by gas chromatography. Methane which is the principal constituent of biogas was 75% (±SD, n=IO) and 2.34 m³.d⁻¹ was measured as biogas yield from the EBRU IAPS. The study also investigated the use of the excess microalgae biomass as a fermentation feedstock for ethanol production and as a co-substrate in order to increase biogas yield from the system. Positive results were achieved for ethanol production from microalgae although yield was generally low. About 385 mg.⁻¹ of ethanol was recovered when glucose was used as substrate, where as only 115 mg.⁻¹ of ethanol was recovered with microalgae as substrate. Suitability of microalgae as feedstock for ethanol generation and biogas generation was determined by characterisation which involved estimation of the carbohydrate, protein and lipid content, and analysis of the C, H, 0, Nand S content. Laboratory fed batch reactors simulated the anaerobic digestion process in order to study the effect of microalgae biomass as co-substrate for biogas generation. The fermenters were inoculated with an active consortium obtained from the Makana municipal waste water works and microbial studies were carried to confirm the presence of the anaerobic consortium. Different pre-treatments (concentrated, rupturing and freeze-drying) were used to disrupt the microalgae prior to introduction into fermenters in a ratio of 3: I. COD, TC, TOC, SO₄⁻² and TN analyses were carried out to monitor nutrient depletion in the system, and biogas generated by the system was quantified by volumetric analysis and the gas composition determined. Statistical analysis (ANOVA) was used to test for significant difference pre and post addition of microalgae. In the most effective fermenter, biogas production was at an average of 394 ml.d·' and CH₄ ratio in the biogas increased by over a 100%. Theoretical methane potential of the IAPS and the Makana municipal waste water works treating 5 ML.d⁻¹ of domestic waste was determined using the empirical formula of waste water and shown to yield 1,037,342.40 m³/yr. The projected biogas yield from this system was used to evaluate its potential use as transportation fuel. In total, 198,673 .55 m³ of biogas was estimated to be required to fuel the Rhodes University's fleet of vehicles, with a residual biogas stream of 838,668.85 m³. It was also demonstrated in the present study that renewable energy sourced from biomass has the potential of supplanting the use of fossil fuel resulting in less pollution leading to a cleaner and healthier environment.
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  • Date Issued: 2012

Microbial monitoring of surface water in South Africa: an overview

  • Authors: Luyt, Catherine D , Tandlich, Roman , Muller, Wilhelmine J , Wilhelmi, Brendan S
  • Date: 2012
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/71636 , vital:29927 , https://doi.org/10.3390/ijerph9082669
  • Description: Infrastructural problems force South African households to supplement their drinking water consumption from water resources of inadequate microbial quality. Microbial water quality monitoring is currently based on the Colilert®18 system which leads to rapidly available results. Using Escherichia coli as the indicator microorganism limits the influence of environmental sources on the reported results. The current system allows for understanding of long-term trends of microbial surface water quality and the related public health risks. However, rates of false positive for the Colilert®18-derived concentrations have been reported to range from 7.4% to 36.4%. At the same time, rates of false negative results vary from 3.5% to 12.5%; and the Colilert medium has been reported to provide for cultivation of only 56.8% of relevant strains. Identification of unknown sources of faecal contamination is not currently feasible. Based on literature review, calibration of the antibiotic-resistance spectra of Escherichia coli or the bifidobacterial tracking ratio should be investigated locally for potential implementation into the existing monitoring system. The current system could be too costly to implement in certain areas of South Africa where the modified H2S strip test might be used as a surrogate for the Colilert®18.
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  • Date Issued: 2012

Microfinance Institutions (MFIs) and rural poverty reduction in the Eastern Cape Province South Africa: a case of Amathole Rural District

  • Authors: Mamutse, Zivai Tapfumanei
  • Date: 2012
  • Subjects: Entrepreneurship -- South Africa -- Eastern Cape , Eastern Cape -- South Africa -- Economic policy , Eastern Cape -- South Africa -- Social conditions , Eastern Cape -- South Africa -- Economic conditions
  • Language: English
  • Type: Thesis , Masters , M Soc Sc (Dev)
  • Identifier: vital:11440 , http://hdl.handle.net/10353/d1007231 , Entrepreneurship -- South Africa -- Eastern Cape , Eastern Cape -- South Africa -- Economic policy , Eastern Cape -- South Africa -- Social conditions , Eastern Cape -- South Africa -- Economic conditions
  • Description: The government of South Africa has seen many financial reforms in the finance industry since the attainment of freedom in 1994. Many microfinance institutions (MFIs) have emerged in the name of poverty reduction, however the impact of MFIs on poverty reduction in rural areas has not been significantly high. Poverty has been reduced but still the inequality gap has even widened (HSRC, 2004). The study is concerned with analysing the impact of MFIs in poverty reduction among the rural poor. Empirical evidence from many developing nations around the world has shown that microfinance is a tool that is relevant in reducing poverty within rural areas. This study investigates the impact of microfinance institutions on household income levels, education and business skills. The study followed a qualitative approach in terms of the research methodology and a survey research design. Data was collected using questionnaires, scheduled interviews, focus group discussions and key informants. Two sample techniques were used for the selection of the MFIs and the household respondents, that is purposive sampling and cluster sampling. In total, 150 households, 15 MFIs and five key informants were interviewed. Descriptive analysis methods were employed and the study showed that only 10 percent of the total households have been able to access microfinance. The number of people who gained business skills was also low (10 percent). The MFIs who provide financial services excluding the other services like business training programmes were 80 percent of the total number of MFIs interviewed. This data showed that only a few (20 percent) MFIs are willing to go an extra mile rendering business skills to their clients. Overally the major finding of the study was that although, MFIs are reaching out to the rural communities, their levels of outreach is still very low within the rural areas. However this does not mean that the impact of MFIs funding is not felt among the rural poor. The levels of income and educational benefits have been increased and felt by the 10 percent of the rural poor clients. This study advocates for an entrepreneurship development pathway to poverty reduction. Microfinance should be used as a source of finance to initiate entrepreneurial activities among the poor in order to generate income. In this study, the use of microfinance finance for consumption by the poor is discouraged because it depletes the funds that can be channeled for selfhelp projects within the rural communities. The study findings motivated the recommendations that encourage an inclusive financial system that is capable of reaching out to the rural poor.
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  • Date Issued: 2012

Microstructural and analytical characterization of plasma dissociated zircon

  • Authors: Minnaar, Ettiénne Gerald
  • Date: 2012
  • Subjects: Zircon , Zirconium
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10547 , http://hdl.handle.net/10948/d1015972
  • Description: This dissertation focuses on the microstructural and analytical characterization of plasma dissociated zircon (PDZ) which was produced by the South African Nuclear Energy Corporation (NECSA). The techniques used in the analysis of the material include scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy and wavelength dispersive X-ray spectrometry (EDS and WDS), infrared spectroscopy, Raman spectroscopy and X-ray diffraction (XRD). The differences in morphology of the zirconia (ZrO2) crystals observed in the PDZ are related to the thermal history of the material. Large zirconia crystals grow in a spherulitic manner and have the monoclinic crystal structure. Some smaller crystals formed via a rapid cooling process appear to retain the tetragonal or cubic crystal structures rather than relaxing to the monoclinic structure, and this may be because such nanocrystals are stabilised by small surface area or constraints from surrounding materials. Impurity distribution analysis of the PDZ showed that majority of the impurities present in zircon segregates to the silica phase during the dissociation process. The infrared and Raman spectroscopy analysis of the PDZ material indicated that the zirconia is present in the monoclinic and tetragonal polymorphs. X-ray diffraction revealed the presence of monoclinic, tetragonal and cubic zirconia phases. Rietveld refinement of the XRD patterns revealed zirconia to be predominantly found in the monoclinic polymorph followed by the tetragonal and cubic polymorphs. A Fourier transform infrared (FTIR) spectrometer equipped with an attenuated total reflectance (ATR) cell proved to be a viable method for determining the percentage dissociated zircon in PDZ.
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  • Date Issued: 2012

Minimum sentence legislation in South Africa

  • Authors: Nzimande, Eric Sibusiso
  • Date: 2012
  • Subjects: South Africa -- Criminal Law Amendment Act, 1997 , Sentences (Criminal procedure) -- South Africa
  • Language: English
  • Type: Thesis , Masters , LLM
  • Identifier: vital:10179 , http://hdl.handle.net/10948/d1012041 , South Africa -- Criminal Law Amendment Act, 1997 , Sentences (Criminal procedure) -- South Africa
  • Description: Legislation regulating minimum sentences in South Africa was re-introduced by sections 51 to 53 of the Criminal Law Amendment Act 105 of 1997 which came into operation on 1 May 1998. These provisions were regarded as a temporary measure to be effective for two years, where after they were extended from time to time. After they had been extended for several times, section 51 was rendered permanent on 31 December 2007 by the Criminal Law (Sentencing) Amendment Act 38 of 2007. At the same time sections 52 and 53 were repealed by the same Act. Minimum sentence legislation was the result of a call by the community for heavier penalties and for the offenders to serve more realistic terms of imprisonment. There was also a general dissatisfaction about the perceived leniency of sentences imposed by the courts for serious crimes. During 1996 and in the wake of these concerns the Minister of Justice requested the South African Law Reform Commission to investigate all aspects of sentencing in South Africa. A Project Committee chaired by a judge of the High Court was appointed and it operated from the late 1996 to March 1998. Minimum sentences for certain serious crimes were one of the options to be investigated by the Project Committee. Consequent to this the Criminal Law Amendment Act 105 of 1997 was promulgated with effect from 1 May 1998. The legislature intended this Act to defer criminal activity, to avoid disparities in sentencing and to deal harshly with perpetrators of serious offences. The subsequent amendments to the Act included the granting of jurisdiction to the Regional court to pass life imprisonment, an automatic right of appeal against life imprisonment in respect of a juvenile accused and identification of circumstances that do not constitute substantial and compelling circumstances. Judicial discretion and departure from prescribed minimum sentences had initially presented a problem regarding its interpretation in a variety of cases in our courts. Eventually our courts came up with a clear interpretation of the meaning of the phrase substantial and compelling circumstances. This research project will analyze the provisions of the Criminal Law Amendment Act 105 of 1997 with regard to minimum sentences for certain serious offences. In the process case law and other literature will be discussed regarding the interpretation of minimum sentence provisions in the Act. Recommendations for legislation which will cover the aspect of sentencing on a wider scale are made.
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  • Date Issued: 2012

Misconceptions in electrostatics among learners at university entry point: a South African case study

  • Authors: Muthiraparampil, Susamma Thomas
  • Date: 2012
  • Subjects: Electrostatics -- Learners -- Education (Tertiary)
  • Language: English
  • Type: Thesis , Masters , M Ed
  • Identifier: vital:18450 , http://hdl.handle.net/11260/d1007755
  • Description: The study explored misconceptions in electrostatics and their origins amongst learners at entry point in a South African University. Available literature showed misconceptions in electrostatics amongst High School learners and confirmed textbooks as one of the sources of misconceptions. It was therefore important to look for misconceptions in electrostatics amongst first year Bachelor of Science (B.Sc 1) learners in physics courses and their origins at the start of the academic year. The study also explored educators' misconceptions in the topic to check whether they could also be a source of learners' misconceptions. The results were intended to give guidance on how to eliminate learners' misconceptions at school rather than carrying them to higher education institutions. The study used the ex-post facto research design and was a case-study. The ex-post facto research design enabled the researcher to investigate whether one or more pre-existing conditions have possibly caused the existing problem of misconceptions. The sample consisted of 198 learners from B.Sc 1 physics course and 28 educators from 15 High Schools in one education district in the Eastern Cape Province of South Africa. The data were collected through questionnaires, analysis of textbooks, and interviews. The Statistical Package for Social Sciences (SPSS) version 17 was used for quantitative analysis whereas categorization and coding were used for qualitative analysis. The study revealed that learners had misconceptions in electrostatics. The origins of misconceptions were traced to educators, textbooks, intuition, daily language and lack of hands-on activities. It emerged from the study that educators also had misconceptions and the cause of their misconceptions were textbooks, websites and gaps in content knowledge. The recommendations from the study were the following: identify preliminary knowledge of learners during introduction of the lesson; introduce the iii constructivist approach to teaching in the teacher training curriculum so that learners at school can be taught using the same approach; frequent upgrading of educators through inservice workshops to reduce educators' misconceptions which, in turn, will help to reduce the misconceptions among learners; introduction of conceptual change textbooks.
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  • Date Issued: 2012

Mitochondrial DNA paradox: sex-specific genetic structure in a marine mussel despite maternal inheritance and passive dispersal

  • Authors: Teske, Peter R , Papadopoulos, Isabelle , Barker, Nigel P , McQuaid, Christopher D
  • Date: 2012
  • Language: English
  • Type: Article
  • Identifier: vital:6836 , http://hdl.handle.net/10962/d1010959
  • Description: Background: When genetic structure is identified using mitochondrial DNA (mtDNA), but no structure is identified using biparentally-inherited nuclear DNA, the discordance is often attributed to differences in dispersal potential between the sexes. Results: We sampled the intertidal rocky shore mussel Perna perna in a South African bay and along the nearby open coast, and sequenced maternally-inherited mtDNA (there is no evidence for paternally-inherited mtDNA in this species) and a biparentally-inherited marker. By treating males and females as different populations, we identified significant genetic structure on the basis of mtDNA data in the females only. Conclusions: This is the first study to report sex-specific differences in genetic structure based on matrilineally-inherited mtDNA in a passively dispersing species that lacks social structure or sexual dimorphism. The observed pattern most likely stems from females being more vulnerable to selection in habitats from which they did not originate, which also manifests itself in a male-biased sex ratio. Our results have three important implications for the interpretation of population genetic data. First, even when mtDNA is inherited exclusively in the female line, it also contains information about males. For that reason, using it to identify sex-specific differences in genetic structure by contrasting it with biparentally-inherited markers is problematic. Second, the fact that sex-specific differences were found in a passively dispersing species in which sex-biased dispersal is unlikely highlights the fact that significant genetic structure is not necessarily a function of low dispersal potential or physical barriers. Third, even though mtDNA is typically used to study historical demographic processes, it also contains information about contemporary processes. Higher survival rates of males in non-native habitats can erase the genetic structure present in their mothers within a single generation.
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  • Date Issued: 2012

Mobile: the challenge of a unique new space for journalism: have you got your mojo?

  • Authors: Malila, Vanessa
  • Date: 2012
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/159517 , vital:40304 , https://hdl.handle.net/10520/EJC135832
  • Description: The speed with which technology is improving in the mobile communications market is widening the scope for opportunity to engage with audiences, provide information and capture their attention for that little while longer. Current technology such as 3G wireless technologies, which allow for high-speed data transmission, and access to multimedia content, as well as smart phones and tablet computers have already illustrated the potential for users to access information that is tailored to mobile devices and available anywhere.
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  • Date Issued: 2012

Modeling economic behaviour in South Africa's informal urban retail trade sector: the case of Port Elizabeth

  • Authors: Qabhobho, Thobekile
  • Date: 2012
  • Subjects: Retail trade -- South Africa -- Port Elizabeth , Business enterprises -- South Africa -- Port Elizabeth
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:9008 , http://hdl.handle.net/10948/d1012855
  • Description: Even though South Africa‟s historical inequalities are addressed, serious economic disparities are still evident. The informal economy is not flourishing as it should be, especially when compared to other fledgling democracies on the continent and this poses a policy question since most of the participants of this sector are from the previously disadvantaged section of the population. One policy dilemma that comes to the fore is about how to ensure that there is increased productivity in the sector so that the sector‟s contribution to the national economy can be enhanced. While the actual share of the economy contributed by the informal economy is difficult to ascertain there is evidence that this constitutes less than one fifth of South Africa‟s GDP. Within the informal economy trading appears to be the dominant economic activity. Despite the importance of the informal trade the sector has not attracted the needed attention in the literature either locally or internationally. The area that has received much attention by researchers has been the informal financial sector. Drawing on a standard revenue model for the informal trade sector this study examines the factors that explain differences in the performance of the retail trade businesses; given that these can be identified an effort should then be made to explore the policy measures that can improve the performance of these firms. The study is based on a sample of 300 informal retail traders in the Port Elizabeth environ. The regression analysis presented in this study suggests that residential area, capital, labour, inventory and age of a business are important determinants of an informal retail trade firm‟s revenue. Very few informal retailers indicated that they had businesses training. The survey results show that having a supplier close to the business assists in reducing transport costs, hence the increase in profit margins. Shelters and storages were found to be very useful in the operation of informal businesses.
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  • Date Issued: 2012

Modelling and mapping the suitability of land for crop production using a combination of GIS and remote sensing in the Eastern Cape: a case study of Mbashe and Mquma local municipalities-South Africa

  • Authors: Vuso, Solly
  • Date: 2012
  • Language: English
  • Type: Thesis , Masters , MSc (Geographic Information System)
  • Identifier: vital:11534 , http://hdl.handle.net/10353/d1019872
  • Description: In order to achieve sustainable agriculture, decision makers require appropriate and fully detailed spatial information on land resources. Crop-land suitability analysis is a prerequisite to achieve optimum utilization of the available land resources for sustainable agriculture rural production (T.R. Nisar Ahamed et al., 2000). It is indeed of paramount importance to identify suitable land for cropping while causing minimum impact to the environment. The Food and Agriculture Organization (FAO, 1976), recommended an approach of land suitability evaluation for crops in terms of suitable land based on climatic and terrain data and soil properties. In this study, an attempt was made to identify suitable areas for massive crop production using remote sensing and GIS methodologies and the knowledge from extension officers. The primary method aims at generating land cover data using SPOT 5 satellite imagery and modeling with the existing land capability. The research purpose was to map the map the number hectares suitable areas for crop production number hectares suitable areas for crop production number hectares suitable areas for crop production number hectares suitable areas for crop production. Spatial modeling techniques were utilized to model land suitability model in an effective and efficiently way. The spatial modeling extension from ESRI product was used to model the crop suitability areas. The model run on ArcGIS platform and due to the fact that modeling only uses raster formats, all the data sets were projected and converted to raster format. The weighted overlay model was used to create land suitability map. The model results revealed that 4046251.79 hectares were suitable for cropping in the study area. The final outputs of suitable areas were calculated and each ward was given a value of suitable area as well as unsuitable area. The validation of the final maps compliments the 500 000 hectares that were mapped by Dept of Agriculture EC using 8% slope as the best potential areas. The method provides a cheap, effective and efficient way to map suitable areas over a large area and it also uses remote sensing data. It is hoped that decision makers will make use of the information produced in this paper as the whole world is in crisis of food security.
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  • Date Issued: 2012

Moderat's Rusty nails and Loie Fuller's Serpentine dance : analysis cloth, the body and movement as symbolic interpretation of meaning in film

  • Authors: Coates, Maran
  • Date: 2012
  • Subjects: Fashion in motion pictures
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:8498 , http://hdl.handle.net/10948/d1015733
  • Description: The main objective of the study is to explore how cloth, the body and movement are able to communicate possible symbolic meaning in Loïe Fuller’s Serpentine Dance film and Moderat’s Rusty Nails music video. The study further attempts to establish the characteristics of fashion film to include cloth, the body and movement and provide a methodology that locates fashion film as a sign system using a visual semiotic analysis framework. The films were then compared and contrasted to determine similarities and differences in their use of cloth, the body and movement. The findings from the film analysis suggest that cloth, the body and movement communicate symbolic meaning in the films based on their associated meanings that are generated both inside and outside the film context. By focussing on cloth, the body and movement as primary communicators (rather than secondary or supporting communicators) in film, new meanings can be interpreted from their interrelationship. The results inform new ways for fashion designers and fashion filmmakers to engage with cloth, the body and movement in fashion film.
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  • Date Issued: 2012

Molecular catalysis of the oxygen reduction reaction by iron porphyrin catalysts tethered into Nafion layers

  • Authors: He, Qinggang , Mugadza, Tawanda , Kang, Xiongwu , Zhu, Xiaobing , Chen, Shaowei , Kerr, John , Nyokong, Tebello
  • Date: 2012
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/243168 , vital:51123 , xlink:href="https://doi.org/10.1016/j.jpowsour.2012.05.043"
  • Description: This study was motivated by the need for improved understanding of the kinetics and transport phenomena in a homogeneous catalyst system for the oxygen reduction reaction (ORR). Direct interaction between the sulfonic groups of Nafion and an Fe(III) meso-tetra(N-methyl-4-pyridyl) porphine chloride (Fe(III)TMPyP) compound was observed using FTIR and in situ UV–Vis spectroelectrochemical characterizations. A positive shift of the half wave potential value (E1/2) for ORR on the iron porphyrin catalyst (Fe(III)TMPyP) was observed upon addition of a specific quantity of Nafion ionomer on a glassy carbon working electrode, indicating not only a faster charge transfer rate but also the role of protonation in the oxygen reduction reaction (ORR) process. A membrane electrode assembly (MEA) was made as a sandwich of a Pt-coated anode, a Nafion® 212 membrane, and a Fe(III)TMPyP + Nafion ionomer-coated cathode. This three-dimensional catalysis system has been demonstrated to be working in a H2/O2 proton exchange membrane (PEM) fuel cell test.
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  • Date Issued: 2012

Molecular chaperone expression and function in breast cancer and breast cancer stem cells

  • Authors: Sterrenberg, Jason Neville
  • Date: 2012
  • Subjects: Breast -- Cancer , Stem cells , Cancer cells
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4141 , http://hdl.handle.net/10962/d1016238
  • Description: The Cancer Stem Cell (CSC) theory suggests that cancers arise from and are maintained by a subpopulation of cancer cells with stem cell properties. Molecular chaperones are key components of cellular regulation. The overexpression of chaperones has become synonymous with cancer cells with chaperones being recognized as bona fide anti-cancer drug targets. Although chaperone activity has been characterized in cancer cells, very little is known about the cellular functions of chaperones in cancer stem cells. We set out to compare the expression of selected molecular chaperones in non-stem cancer cell and cancer stem cell enriched populations isolated from breast cancer lines, in order to identify chaperones differentially expressed between the two populations for further biological characterization. In order to isolate breast cancer stem cells from the MCF-7 and MDA-MB-231 breast cancer cell lines, three cancer stem cell isolation and identification techniques were utilized based on (1) cell surface marker expression (CD44+/CD24- and CD44+/CD24-/EpCAM+ phenotypes), (2) aldehyde dehydrogenase enzyme activity (ALDHHi) and (3) ability to grow in anchorage-independent conditions. The MDA-MB-231 and MCF-7 breast cancer cell lines displayed CD44+/CD24- cell populations with the MCF-7 cell line additionally displaying a large CD44+/CD24-/EpCAM+ population. Although both cell lines showed similar ALDHHi populations, they differed substantially with respect to anchorage-independent growth. MCF-7 cells were able to form anchorage-independent colonies while the MDA-MB-231 cell line was not. Anchorage-independent MCF-7 cells showed enrichment in CD44+/CD24- and CD44+/CD24-/EpCAM+ cells compared to adherent MCF-7 cells, and were selected for gene expression studies. Gene expression studies identified 22 genes as being down-regulated at the mRNA level in the anchorage-independent MCF-7 cells, while only 2 genes (BAG1 and DNAJC12) were up-regulated. The down-regulation of selected chaperones in anchorage independent MCF-7 cells was confirmed at the protein level for selected chaperones, including DNAJB6, a type II DNAJ protein shown to be involved in the regulation of Wnt signaling. In order to characterize the effect of DNAJB6 expression on BCSCs we developed a pCMV mammalian expression plasmid for both DNAJB6 isoforms (DNAJB6L and DNAJB6S). We successfully constructed mutants of the conserved histidine-proline-aspartic acid (HPD) motif of the J domain of DNAJB6S and DNAJB6L. These constructs will allow the analysis of the role of DNAJB6 in cancer stem cell function. To the best of our knowledge, this is the first report to focus on the comparative expression of molecular chaperones in normal and cancer stem cell enriched breast cancer populations.
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  • Date Issued: 2012

Molecular detection and drug susceptibility of Mycobacterium tuberculosis complex in raw milk from a major dairy farm in the Nkonkobe region, Eastern Cape Province, South Africa

  • Authors: Silaigwana, Blessing https://orcid.org/0000-0002-3324-1607
  • Date: 2012
  • Subjects: Mycobacterium tuberculosis , Drug resistance in microorganisms , Tuberculosis -- Pathogenesis
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10353/24239 , vital:62543
  • Description: Mycobacterium tuberculosis complex (MTBC) organisms are the causative agents of tuberculosis in humans as well as animals. The study aimed to use molecular techniques for detection and drug susceptibility testing of MTBC in raw milk from cattle at a dairy farm in the Nkonkobe region of South Africa. Two hundred samples (100mL each) were collected and processed using the modified Petroff’s method. DNA was isolated using the Zymo Research bacterial DNA kit and amplified using the Seeplex® MTB Nested ACE assay. Drug susceptibility testing was performed using the Genotype® MTBDRplus assay. MTBC DNA was detected in 11 (6percent) of the samples tested. Resistance to both rifampicin and isoniazid was detected in 90.9percent of the positive samples. The most frequent rpoB mutations detected were H526Y (90percent), H526D (80percent), S531L (60percent) and D516V (20percent). No mutation was detected in the katG gene. All isoniazid resistant samples harboured mutations in the inhA gene. The most frequent (100percent) mutation conferring low level isoniazid resistance was the T8A substitution. The inhA mutations C15T, A16G and T8C were equally represented with 60percent frequency. A high prevalence of multi-drug resistance was noted in the Nkonkobe region. Therefore, the results of this study have clinico-veterinary and epidemiological significance and calls for further studies and necessary actions to delineate the situation. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
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  • Date Issued: 2012

Molecular phylogenetics of Oestroidea (Diptera: Calyptratae) with emphasis on Calliphoridae: insights into the inter-familial relationships and additional evidence for paraphyly among blowflies

  • Authors: Marinho, M A T , Junqueira, A C M , Paulo, D F , Esposito, M C T , Villet, Martin H , Azeredo-Espin, A D
  • Date: 2012
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/442691 , vital:74023 , https://doi.org/10.1016/j.ympev.2012.08.007
  • Description: The superfamily Oestroidea, comprising ∼15,000 species, is a large and ecologically diverse clade within the order Diptera. Among its six commonly recognized families, Calliphoridae seems to be crucial for understanding evolutionary relationships in the group, as it is recognized as a controversial paraphyletic grouping. To further investigate this matter, the ITS2, 28S, COI and 16S regions were used to infer phylogenetic relationships in Oestroidea with maximum-parsimony (MP), maximum-likelihood (ML) and Bayesian inference (BI) methods. For the BI analyses, a deep evaluation of different data partitioning strategies was conducted, including consideration of structural conformation (ITS2 and 16S) and codon position (COI) information.
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  • Date Issued: 2012

Morphological variation and species diversity of South African Estuarine macrophytes

  • Authors: Veldkornet, Dimitri Allastair
  • Date: 2012
  • Subjects: Estuarine ecology -- South Africa , Aquatic plants -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10635 , http://hdl.handle.net/10948/d1013001
  • Description: Studies on morphological variation are important as it can depict the relationship with environmental factors clearly and convey an understanding of the manner, mechanism and factors influencing plant adaptation and evolution. Although many studies have been conducted on South African salt marsh plant physiology and phytosociology there are at present very few morphological studies on estuarine plants. The aim of this study was to compare the morphological variation of estuarine macrophytes in three different estuary types in the warm temperate biogeographic zone of South Africa and to compare characters used in the taxonomic descriptions of species with those measured in the field. Permanently open estuaries investigated were Ngqusi (WC), Kowie (KW) and Swartkops (SW) estuaries. The Knysna Estuary (KN) was the estuarine bay investigated and the temporarily open/ closed estuaries (TOCEs) were the East Kleinemonde (EK) and Great Brak (GB) estuaries. Macrophytes were morphologically different across different estuary types. This suggests that there were different factors operating between these estuary types that would directly influence the morphology of species. The variation of plant height with different estuary types can be attributed to the fact that smaller salt marshes also have smaller habitat ranges compared to larger ones. The variation in morphological characteristics such as plant height can also be attributed to biogeographical range. Most morphological characteristics measured in the field fall within previously published ranges, and so these characters are useful in delimiting species. There were significant relationships between phenotypic variables and multivariate environmental variables. The most important of these variables were soil electrical conductivity, soil organic content and soil water content. Specifically, plant height increased with water content and decreased with salinity, flower stalk length had strong significant positive correlations with moisture content, organic content and pH while there were strong significant correlations with redox potential and electrical conductivity. Salt marshes are considered ideal for studying variation of species due to the explicit environmental gradients and plants occurring in salt marshes are halophytes that exhibit a range of morphological traits that allows for growth and reproduction under the stressful and extreme conditions. Considering recent climate change predictions and the consequent effects on South African estuaries this study provides significant information with regard to the response of species to a changing environment. The study was also aimed at updating the existing botanical database for South African estuaries in terms of species occurrence in South African estuaries, taxonomic name changes of existing species, new species, common names and habitats. Species diversity indices were also calculated for different estuaries, estuary types and biogeographic zones and diagnostic descriptions of the dominant salt marsh species were developed. The objective of this was that these data should provide baseline information for determining habitat richness and plant species diversity of South African estuaries which in turn should be used in determining priority estuaries for conservation and management. The identification key, developed using the DELTA software, would also aid researchers, managers and laymen in identifying salt marsh species. Results showed that the total number of macrophyte species, including intraspecific taxa and macroalgae, was 242 in 53 estuaries that were updated . There was an increase in the number of taxa recorded in the database primarily due to 1) research focus and full taxonomic surveys on larger estuaries and the big research projects has led to the identification of more species, 2) the addition of species that are not characteristically known as estuarine species, 3) the addition of 50 macroalgal taxa and 4) minor changes due to taxonomic revisions of species and the addition of newly described species. The Shannon diversity index showed that greater species diversity was found in the Berg (Groot) Estuary (4.220) and the Uilkraals Estuary (4.025). The cool temperate bioregion was the most diverse in the number of taxa (58) with the highest Shannon index (4.736). Permanently open estuaries were the most diverse in the number of unique taxa (56) with the highest Shannon index (4.867). Estuarine managers need to be aware of the species diversity in different estuarine types as well as the associated impacts on them. Conservation planning must therefore include species. Diagnostic features of INTKEY indicated that all 57 taxa were distinguishable from each other. Contrary to expectations plant height and not floral morphology was the best diagnostic characteristic. Ecological information such as the estuarine habitat, where different life forms occur, was important in delimiting species.
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  • Date Issued: 2012
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