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An investigation of the effect of co-solvents on the hydrothermal liquefaction of microalgae biomass

  • Authors: Nongauza, Sinethemba Aubrey
  • Date: 2015
  • Subjects: Biomass chemicals Microalgae -- Biotechnology , Supercritical fluids Solvents
  • Language: English
  • Type: Thesis , Doctoral , DPhil
  • Identifier: http://hdl.handle.net/10948/21667 , vital:29731
  • Description: The study introduces and demonstrates the viability of the continuous flow reactor (CFR) system for the production of bio-crude oil (BCO) from wet microalgae. Preliminary experiments conducted in the CFR system in hot compressed water (HCW) were successful in converting wet microalgae into liquid BCO. However, the synthesis and aggregation of high boiling point (HBP) components of BCO and the accumulation of char in the tubular piping of CFR system were identified as the limiting factor to the viability of the system. The aggregation of HBP components and the accumulation of char result to system blockage which prevents the continuous flow of the liquefaction product mixture in the CFR system. Inhibiting the reactions leading to the formation of HBP components and char will improve the performance of the CFR system. Therefore, the study seeks to incorporate co-solvents in the liquefaction reaction media in an attempt to inhibit or minimize the prevalence of HBP components of BCO. As such, different co-solvents were screened for their influence on improving the quality of BCO with respect to its boiling point profile (BPP), initial and final boiling point, as well as the amount of char recovered from each experiment. Only one co-solvent was chosen for further exploration in the CFR system. Batch liquefaction reactor’s (BLR) made up of stainless steel were used to carry out the co-solvent screening experiments. These experiments were carried out at a constant temperature (280 °C), pressure (75 bar), and co-solvent concentration (10 wt.%), at varying residence times. Solvent extraction with dichloromethane (DCM) was performed on the liquefaction product mixture to separate the products, viz. BCO, char and water soluble components. The extracted BCO was analysed through simulated distillation (SimDis) to obtain the BPP. The BPP properties of the BCO samples, from different liquefaction media, and the amount of char recovered were highly influenced by the addition of a co-solvent. The final boiling point (FBP) of tetralin, heptane, and n-octanol BCO products were significantly reduced to below 500 °C for all tested residence times except at 20 minutes. The residence time also proved to be influential in the processing of wet microalgae. n-Octanol was selected as the optimal performing co-solvent and was used for the continuous liquefaction of wet microalgae in the CFR system. The CFR system was modified by adding a co-solvent feed line into the continuous system since n-octanol was insoluble in water. The n-octanol pump was set at different flow rates, 0.2, 0.3, and 0.4 g/min, which resulted in a concentration of about 10 wt.% in the reactor feed. The concentration of n-octanol had a significant influence on the BPP of BCO components. The FBP’s were reduced with an increase in n-octanol concentration. The initial boiling point (IBP) of n-octanol BCO was increased to just above 100 °C which was required for the stability of the BCO product. The components of BCO were identified by GCMS. n-Octanol also proved to affect the composition of the BCO with respect to its components. HCW BCO components were significantly different from those identified from n-octanol BCO. A second co-solvent (tetralin) was used to prove whether the difference on the components of BCO was affected by n-octanol. The results proved that indeed the addition of different solvents in liquefaction reaction media favours the formation of different components. The amount of char formed was also reduced when using a co-solvent. A decrease in the oxygen/nitrogen compounds was also observed in the presence of a co-solvent, thus improving BCO properties.
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  • Date Issued: 2015

An investigation of the strategies for sustainability of selected community radio stations in Transkei rural areas of the Eastern Cape

  • Authors: Mafani, Hlanga Eric
  • Date: 2015
  • Subjects: Community radio -- South Africa -- Eastern Cape , Radio stations -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10948/5963 , vital:21020
  • Description: This research project was aimed at investigating strategies that are used for the sustainability of selected rural-based community radio stations in the Transkei area of the Eastern Cape. The study was done under a hypothesis that, in the absence of big business and migration of literate people and skilled labour from rural communities to urban centres, rural-based community radios struggle to attract operational revenue through advertising, community support, etc., and that the supposedly high illiteracy in the rural areas render it difficult to run the stations. Two rural-based community radio stations were selected for this study: Alfred Nzo Community Radio at Mount Ayliff in the Alfred Nzo District Municipality area, and Vukani Community Radio at Cala in the Chris Hani District Municipality area. The aim was to study their activities with regard to the most and widely agreed three-dimensional method of sustaining community radio stations: Financial Sustainability, Institutional Sustainability, and Social Sustainability. Relevant literature has been reviewed and data have been collected using both quantitative and qualitative methods through questionnaires. The study however leans more on the qualitative approach and a quantitative approach has merely been used to identify the trends of the views of the participants. The analysis of data highlights the views of the respondents about these radio stations with regard to their strategies to sustain themselves. The views of the respondents represent all people from all levels of people involved in the stations: From the Member of the Board of Directors in the boardroom to stations’ members of management at their desks. From Presenters behind their microphones to the listener in the dusty streets of the poor rural areas. The results confirm the hypothesis that the areas have high unemployment and illiteracy rates, and that their sustainability depend largely on trade-outs with local business and government support. However, the study also shows that strategies for Financial Sustainability, Institutional Sustainability, and Social Sustainability may overlap or influence each other. For instance, an activity of Institutional Sustainability may result in Financial Sustainability, and visa-versa. The study also reveals that the stations struggle to establish and maintain effective Social Sustainability for the benefit of the station. In the light of this, a proposal for further study and recommendations are given at the end of the study.
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  • Date Issued: 2015

An organic rankine cycle heat engine using a rock thermal battery as the heat source

  • Authors: Humm, Jason Christopher
  • Date: 2015
  • Subjects: Heat engineering Renewable energy sources
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: http://hdl.handle.net/10948/10960 , vital:26861
  • Description: Organic Rankine cycles (ORC) have unique properties that are well suited to power generation from low grade heat sources. It is envisaged that a domestic scale ORC Heat Engine can be developed that will be able to run off heat stored in a solar charged rock thermal battery. The use of a thermal battery as the heat source for the ORC system will provide the user with electricity during the day and for a number of hours into the night. The concept presented consists of four key components: rock thermal battery, 1 kW scroll expander, condenser and working fluid pump.
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  • Date Issued: 2015

An overview of energy minerals in the Springbok Flatsbasin, South Africa : implications for geochemical and geophysical exploration

  • Authors: Ledwaba, Lebogang John
  • Date: 2015
  • Subjects: Energy minerals -- South Africa -- Springbok Flats (Limpopo) , Geochemistry , Prospecting -- Geophysical methods , Coal -- South Africa -- Springbok Flats (Limpopo) , Uranium -- South Africa -- Springbok Flats (Limpopo) , Coalbed methane -- South Africa -- Springbok Flats (Limpopo)
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5092 , http://hdl.handle.net/10962/d1019880
  • Description: This study is informed by the rising demand for power needs in South Africa and aims at understanding the geophysical and geochemical characteristics of the energy minerals in the Springbok Flats Basin and relating them to the prevailing geological and structural setting for improved exploration targeting. The Springbok Flats Basin is part of the Karoo sediments and host to uranium, coal and coal bed methane (CBM) resources. The lithology sections in the basin indicate presence of basaltic lavas at the top, underlain by mudrocks, siltstones, sandstones, conglomerates and diamictite, with interbedded coal beds occasionally. The coals are uraniferous and shale bounded and of lower Beaufort age at 250 Ma. The regional radiometric data identifies the regional extent of the Springbok Flats Basin as a basin with low total count values. This information is useful in exploration as it gives an idea of the limits of the area where to focus application for prospecting licenses. The reduced to pole of the total magnetic field, residuals and first vertical derivative maps clearly show the high magnetic susceptibility nature of the surrounding Bushveld rocks as compared to the low Karoo sediment susceptibility within the basin. There are distinct ring shaped picks within the basin possibly due to known Karoo dolerite sills in particular to the central south western part of the grid. The regional geochemical mapping program is a cost-effective way of providing an overview of the relative abundance levels, regional trends and anomalous patterns in the underlying lithological units. Background values of elements in soils over different lithological units and the identification of anomalous values relative to these elements can easily be identified. The geochemical results show an excellent correlation between soil chemistry and underlying geological formations. A few distinct gravity highs are clearly shown within the basin. Assuming the effect of the Letaba basalt to the gravity readings is uniform across the basin; these distinct anomalies could be due to Karoo dolerite sills as they coincide with areas of distinct high magnetic signature. A conceptual model was generated assuming that the Karoo sediments’ layering is uniform across the gravity profile but changes in the residual are due to an increased thickness of the sill supported by the gentle changes on the surface topography. Satellite imagery has got its challenges especially in areas of vegetation but it does provide a very useful tool in exploration. A number of spectral analysis techniques and band rations can be used to differentiate the areas underlain by the Letaba basalts, the Karoo sandstones/shale and Bushveld granites for mapping purposes. The priority focus will be on the shallower Karoo sediments because of the potential for cheaper mining. Exploration targeting needs to be guided by observed geochemical and geophysical characteristics in order to prioritize areas taking into account the presence of Karoo intrusives such as the dolerite sills that tend to devolatize the coal hence affecting the quality/rank. Structures and gravity signatures are very important in delineating areas with thick sediments that have a potential for CBM. The same understanding in targeting goes a long way in planning drill holes, resource modelling and pre-feasibility stages for mine planning. A high resolution airborne geophysical survey is recommended over the basin to better resolve structures. Geophysical borehole logging is recommended to be part of the exploration drilling programs in the Springbok Flats Basin in order to define the in-situ geophysical characteristics. Geophysical logging is useful in particular for the uranium reserves that cannot be delineated from the surface due to deep intersection.
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  • Date Issued: 2015

Analysing from experience : Gustav Mahler’s Quartetsatz for piano and strings

  • Authors: Du Plessis, Jacques
  • Date: 2015
  • Subjects: Mahler, Gustav, 1860-1911. -- Quartet, piano, violin, viola, cello, A minor , Musical analysis , Music appreciation , Phenomenology and music
  • Language: English
  • Type: Thesis , Masters , MMus
  • Identifier: vital:2696 , http://hdl.handle.net/10962/d1017818
  • Description: Musical analysis has traditionally been located within the context of musicology. It is therefore an activity usually considered the purview of music scholars rather than practical musicians. The musical analyses produced by music scholars therefore provide us with intellectual understandings of musical works, rather than insights into the experience of listening to or playing music. In this thesis, I will propose that those agents involved in practical music-making can produce insights into musical works that are as valid as the work of traditional music scholarship. I will attempt to re-conceptualize the position of the ‘knower’ or ‘experiencer’ - the performer - of music as one with primary access to knowledge of a musical work, and therefore ideally suited to offer analyses of these works. The establishment of the performer as a bearer of central analytical knowledge functions in direct opposition to the traditional distinction between ‘theory’ and ‘practice’. My thesis will trace the Platonic origins of the philosophical separation of practice and research, and as an alternative to the traditional separation of practice and research, I shall explore the concept of Practice-Based Research (PBR). My exploration of PBR will be informed by phenomenological approaches to music scholarship. As a field of enquiry which concerns itself with experience, the phenomenology of music suggests that the mind and body of the practitioner are important sources of musical insight. To address this issue, Bourdieu’s notion of habitus will be explored. The habitus will be shown to contain a vast network of socio-cultural codes informing the practitioner’s relationship with the musical work. A central aim of this thesis is to explore the possibilities of using practice-based research as the foundation for the study and analysis of a composition, in order to allow for a deeper understanding of the work by means of the generation and harnessing of practical knowledge. Thus, the theoretical outline of PBR provided in this thesis will be applied to a piece of practical performance-based analysis. As such, an analysis of Mahler’s Quartetsatz will be used as the basis on which to draw knowledge in this project.
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  • Date Issued: 2015

Analysis of calendar effects and market anomalies on the Johannesburg Stock Exchange

  • Authors: Atsin, Achiapo Jessica Lisette
  • Date: 2015
  • Subjects: Stock exchanges -- South Africa -- Johannesburg , Stocks -- South Africa
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:9028 , http://hdl.handle.net/10948/d1020372
  • Description: This study sought to empirically investigate the existence of calendar effects and market anomalies on the JSE using monthly and daily closing prices of the ALSI, Top 40, Mid Cap and Small Cap index; as well as, daily closing prices on the Value, Growth and Dividend Plus index during the sample period 2002 – 2013. The anomalies analysed are the January effect, the weekend effect, the size effect, the value effect, and the dividend yield effect. The empirical analysis uses a number of MSAR with a different number of regimes and lag orders. The results from the investigation of the January effect show the non-existence of the January effect and the value effect on the JSE during the periods 2002 – 2013 and 2004 – 2013, respectively. However, the weekend effect was found significant in the Mid Cap and the Small Cap index, and the size effect was also found significant during the same period 2002 - 2013. Finally the results from a Granger causality test concluded that there is a relationship between the returns on the Dividend Plus index and the ALSI, effectively proving the existence of the dividend yield effect on the JSE between 2006 and 2013. Additionally, the anomalies found imply the opportunity for investors to make returns above buy-and-hold.
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  • Date Issued: 2015

Analysis of predictive power of binding affinity of PBM-derived sequences

  • Authors: Matereke, Lavious Tapiwa
  • Date: 2015
  • Subjects: Transcription factors , Protein binding , DNA-binding proteins , Chromatin , Protein microarrays
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4161 , http://hdl.handle.net/10962/d1018666
  • Description: A transcription factor (TF) is a protein that binds to specific DNA sequences as part of the initiation stage of transcription. Various methods of finding these transcription factor binding sites (TFBS) have been developed. In vivo technologies analyze DNA binding regions known to have bound to a TF in a living cell. Most widely used in vivo methods at the moment are chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) and DNase I hypersensitive sites sequencing. In vitro methods derive TFBS based on experiments with TFs and DNA usually in artificial settings or computationally. An example is the Protein Binding Microarray which uses artificially constructed DNA sequences to determine the short sequences that are most likely to bind to a TF. The major drawback of this approach is that binding of TFs in vivo is also dependent on other factors such as chromatin accessibility and the presence of cofactors. Therefore TFBS derived from the PBM technique might not resemble the true DNA binding sequences. In this work, we use PBM data from the UniPROBE motif database, ChIP-seq data and DNase I hypersensitive sites data. Using the Spearman’s rank correlation and area under receiver operating characteristic curve, we compare the enrichment scores which the PBM approach assigns to its identified sequences and the frequency of these sequences in likely binding regions and the human genome as a whole. We also use central motif enrichment analysis (CentriMo) to compare the enrichment of UniPROBE motifs with in vivo derived motifs (from the JASPAR CORE database) in their respective TF ChIP-seq peak region. CentriMo is applied to 14 TF ChIP-seq peak regions from different cell lines. We aim to establish if there is a relationship between the occurrences of UniPROBE 8-mer patterns in likely binding regions and their enrichment score and how well the in vitro derived motifs match in vivo binding specificity. We did not come out with a particular trend showing failure of the PBM approach to predict in vivo binding specificity. Our results show Ets1, Hnf4a and Tcf3 show prediction failure by the PBM technique in terms of our Spearman’s rank correlation for ChIP-seq data and central motif enrichment analysis. However, the PBM technique also matched the in vivo binding specificities of FoxA2, Pou2f2 and Mafk. Failure of the PBM approach was found to be a result of variability in the TF’s binding specificity, the presence of cofactors, narrow binding specificity and the presence ubiquitous binding patterns.
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  • Date Issued: 2015

Androcentrism and misogyny in late twentieth century rock music

  • Authors: Berkland, Darren Gary
  • Date: 2015
  • Subjects: Music -- Social aspects , Gender identity in music , Music -- Performance -- Psychological aspects , Emotions in music , Rock musicians
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:8440 , http://hdl.handle.net/10948/d1021199
  • Description: Judith Butler’s writings on gender ostensibly changed the way gender is considered with regard to an individual’s subjectivity. Her writings expressed a discursive parameter that changed the theoretical standpoint of gender from that of performance, to that of performativity. In short, the notion of gender became understood as a power mechanism operating within society that compels individuals along the heteronormal binary tracts of male or female, man or woman. Within the strata of popular culture, this binarism is seemingly ritualized and repeated, incessantly. This treatise examines how rock music, as a popular and widespread mode of popular music, exemplifies gender binarism through a notable ndrocentrism. The research will examine how gender performativity operates within the taxonomy of rock music, and how the message communicated by rock music becomes translated into a listener’s subjectivity.
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  • Date Issued: 2015

Antibiotic stewardship: the role of clinical pharmacist

  • Authors: Ramkhalawon, Shabeerah
  • Date: 2015
  • Subjects: Hospital pharmacies -- South Africa Pharmacists -- South Africa
  • Language: English
  • Type: Thesis , Masters , MPharm
  • Identifier: http://hdl.handle.net/10948/10858 , vital:26830
  • Description: South Africa has a high prevalence of infectious diseases; the major ones being the Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome epidemic, and tuberculosis. South Africa’s burden of resistant bacteria is also increasing. Antibiotic resistance in hospitalised patients leads to an increase in morbidity and mortality, resulting in longer hospital stays, and an increase in hospital costs. In order to counteract the problem of antibiotic resistance in hospitals and other healthcare facilities and preserve the efficacy of currently available antibiotics, there is a need for serious antibiotic management. Antibiotic stewardship initiatives have thus been put in place to guide healthcare professionals on the correct use of antibiotics. Clinical pharmacists can intervene and contribute to antibiotic stewardship owing to comprehensive knowledge of antibiotics, including the properties, uses, safety and efficacy of individual agents. There is a paucity of research to support the role of the clinical pharmacist in antibiotic stewardship in public sector hospitals. The current pharmacist staffing system within public sector hospitals does not adequately support pharmacists, in particular clinical pharmacists, to participate actively in antibiotic stewardship. The primary aim of the study was to evaluate the role of the clinical pharmacist in antibiotic stewardship in a public hospital setting. A secondary aim was to contribute towards more rational inpatient use of antibiotics in the general medical ward. The hypothesis for the study was that clinical pharmacists can make a positive contribution to the correct use of antibiotics in a public hospital setting. The study showed that the introduction of a pharmacist-driven antibiotic stewardship in the ward, using a prospective audit and feedback strategy, had a positive effect on overall appropriateness of antibiotic prescribing (Chi2=7.89; df=3; p=0.04815, Cramer’s V=0.13). However, this finding did not show any reduction in the volume of antibiotic use. Positive patient outcomes were achieved and shown through a reduction in the length of hospital stay (p=0.00487; one-way ANOVA). Although patients were not followed up on discharge to assess re-admission rates, the results are relevant in order to inform the hospital staff about the implementation of antibiotic stewardship at the public hospital setting with the aims of reducing inappropriate antibiotic prescribing and improving patient outcomes. From the results of the study, it can be concluded that the hypothesis was achieved and that the clinical pharmacist did play an integral role in antibiotic prescribing at the public hospital setting. Thus, it can be concluded that the study, though limited in its scope, achieved its aims and objectives, and showed that the clinical pharmacist does play an integral role in the rational use of antibiotics in a public hospital setting.
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  • Date Issued: 2015

Antjie Krog and the post-apartheid public sphere: Speaking poetry to power

  • Authors: Garman, Anthea
  • Date: 2015
  • Language: English
  • Type: text , book
  • Identifier: http://hdl.handle.net/10962/159913 , vital:40355 , ISBN 978-1869142933
  • Description: Antjie Krog has been known in Afrikaans literary circles and the media for decades because of her poetry and her strong political convictions. Often known simply as 'Antjie,' she is also affectionately called 'our beloved poet' and our 'Joan of Arc' by Afrikaans commentators. It was through her work on the Truth and Reconciliation Commission as an SABC radio journalist and her subsequent book, Country of My Skull, that Antjie Krog then became known to English-speakers in South Africa and across the world. Her work catapulted her particular brand of poetics and politics, honed over many years of her opposition to apartheid, into the South African public sphere at a time when the country was not only looking for a humane and just resolution after the apartheid era, but was also establishing itself as a new democracy.
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  • Date Issued: 2015

Anton and Vale van der Merwe: reinterpreting Afro-Oriental studio ceramics traditions in South Africa

  • Authors: Steele, John
  • Date: 2015
  • Language: English
  • Type: text , Article
  • Identifier: http://hdl.handle.net/11260/968 , vital:30077
  • Description: Growing awareness of ancient Chinese Song and Yuan ceramics, amongst other Oriental traditions, by people with western connections such as Bernard Leach and Michael Cardew, in conjunction with influences from Japanese associates such as Soyetsu Yanagi, Kenkichi Tomimoto, and Shoji Hamada, (De Waal 1997, Harrod 2012, Kikuchi 1977, Leach 1976) has had many consequences. It spread a consciousness idealizing self-sufficient pottery studios where potters were in touch with all aspects of creating utilityware, largely from local materials for local use. Out of this emerged an Anglo-Oriental studio ceramic philosophy of form and practice, associated mainly with hand-made high temperature reduction fired ceramics. These ideas spread to South Africa in the late 1950s, and by the early 1960s local studios were being established along these lines. This studio ceramics movement grew exponentially in South Africa, initiating a phase of Afro-Oriental ceramics that remains a powerful way of life and visual arts influence. This paper seeks to explore aspects of Afro- Oriental studio ceramics in South Africa, with particular reference to the Leach/Hamada/Cardew to Rabinowitz, and Van der Merwe lineage.
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  • Date Issued: 2015

Application of bacteriocins in the preservation of fruit juice

  • Authors: Bodley, Mark David
  • Date: 2015
  • Subjects: Bacteriocins , Fruit juices -- Preservation
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:10345 , http://hdl.handle.net/10948/d1020188
  • Description: Bacteriocins (BCNs) are ribosomally synthesized polypeptides or proteins with antimicrobial activity, produced by different groups of bacteria. Many lactic acid bacteria (LAB) produce BCNs with broad spectra of inhibition. The antimicrobial activity of BCNs against spoilage organisms (SPOs) has raised considerable interest in their application in juice preservation. The objectives of the study were to: (i) isolate, identify and screen BCN producing bacteria for antimicrobial activity against spoilage bacteria and fungi, (ii) optimize production of BCN from selected producers and (iii) investigate the industrial application of the BCN as a preservative in fruit juice. Eleven LAB strains of BCN producers were screened for antimicrobial activity. BCNs from Lactobacillus plantarum and Pediococcus pentosaceus 34 were the most effective against juice spoilage bacteria and fungi. The effect of medium components on bacteriocin production in L. plantarum and P. pentosaceus 34 was also determined. Clementine:Valencia (1:1) juice was used for the first time as the growth medium for L. plantarum and P. pentosaceus 34. The BCN from L. plantarum showed the highest activity and was, therefore, chosen for juice fermentation studies. The identification of L. plantarum was confirmed by biochemical tests, polymerase chain reaction (PCR) and sequencing of the recA gene. The highest BCN activity was observed for L. plantarum grown in De Man-Rogosa-Sharpe (MRS) and a combination of all supplements (i.e. peptone, MnSO4.H2O, Tween 80, glucose and whey), followed by MRS and Tween 80, peptone, MnSO4.H2O and MRS alone. MRS was a better medium for BCN production than juice [Clementine:Valencia (1:1)]. Size exclusion chromatography (SEC) was used to isolate the active L. plantarum BCN fraction which corresponded to an approximate molecular weight of 3.2 kDa and was proteinaceous in nature. Plantaricin structural genes (plnEF, plnJ, plnK, plnN) were detected in the L. plantarum strain by PCR and sequenced, and were chromosomally encoded as no plasmids could be detected. This implies that the BCN from L. plantarum is most likely a type of class IIa plantaricin which is responsible for the broad inhibitory activity observed. For the industrial application studies, L. plantarum BCN-containing cell free supernatant (BCNsup) added to “Ready to Drink” (RTD) Clementine:Valencia (1:1) juice at concentrations of 3 600 - 500 000 ppm decreased growth of SPOs, Lactobacillus acidophilus and Streptococcus thermophilus. At 250 000 ppm, the L. plantarum BCNsup achieved 5.3 and 6.8 log reductions of the L. acidophilus, after 24 and 48 h, respectively, which is larger than the USFDA (2001) requirement of a 5 log reduction in SPO activity, for preservation of fruit juices. However, there was a decrease in the activity when the BCNsup was applied to industrial (Valor) RTD juice (mango-orange) at decreasing concentrations of 100 000, 50 000 and 25 000 ppm. Organoleptic tests showed that the BCN did not alter flavor or taste of the juice and did not cause toxicity or allergic reactions. A food safety risk assessment was conducted in order to determine the Critical Control Point(s) [CCP(s)] at which the BCN could be applied to control identified microbiological hazards, and a Hazard Analysis and Critical Control Point (HACCP) plan was developed. This is the first report on the optimisation of L. plantarum BCN production in juice [Clementine:Valencia (1:1)], followed by inoculation into RTD juice (mango-orange), including a HACCP plan for the application of the BCN as a preservative in juice.
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  • Date Issued: 2015

Application of Baylis-Hillman methodology in the synthesis of HIV-1 enzyme inhibitors

  • Authors: Manyeruke, Meloddy Hlatini
  • Date: 2015
  • Subjects: HIV infections , Enzyme inhibitors , AZT (Drug) , Bioconjugates
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4540 , http://hdl.handle.net/10962/d1017920
  • Description: The application of Baylis-Hillman methodology has afforded access to a range of β-hydroxypropionate ester-AZT conjugates as potential dual-action HIV-1 IN/RT inhibitors. Two families comprising a total of nine β-hydroxypropionate ester-AZT conjugates were synthesised. The first family was accessed using O-benzylated salicylaldehydes and methyl acrylate and the second from unprotected salicylaldehydes using tert-butyl acrylate as the activated alkene. Spectroscopic methods were employed to fully characterize the compounds. Propargylation of the respective Baylis-Hillman adducts was achieved via conjugate addition of propargylamine. The resulting products were then employed in Cu(I)-catalysed “click” reactions with azidothymidine (AZT) to yield the desired β-hydroxypropionate ester-AZT conjugates. Exploratory studies were also conducted to access 4-hydroxycoumarins from Baylis-Hillman derived adducts and to construct customized chiral Baylis-Hillman reaction sites. Many 4- hydroxycoumarins are known to exhibit a wide range of biological activities, and extending Baylis-Hillman methodology to access these systems is an important challenge. Two approaches were investigated. The first involved the formation of a 4-phthalimidocoumarin, aromatisation and hydrolysis of which was expected to lead to the 4-hydroxycoumarin target. The second, a variation of the first, involved the use of 4-(chrolomethyl)coumarin intermediates. Unfortunately, while various intermediates were prepared and characterised, neither approach led ultimately to the desired targets. N-substituted borneol-10-sulfonamides were constructed from camphor-10- sulfonyl chloride as chiral Baylis-Hillman reaction sites. In a preliminary study, however, none of the N-substituted borneol-10-sulfonamides exhibited Baylis-Hillman catalytic activity.
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  • Date Issued: 2015

Applications of social media and web 2.0 for research support in selected African academic institutions

  • Authors: Owusu-Ansah, Christopher M , Gontshi, Vuyokazi , Mutibwa, Lois , Ukwoma, Scholarstica
  • Date: 2015
  • Subjects: Social networks , Web 2.0. , Research -- Study and teaching
  • Language: English
  • Type: Article
  • Identifier: vital:6996 , http://hdl.handle.net/10962/d1018520
  • Description: This study examined the use of Social Media/Web 2.0 for research support and it is guided by three objectives namely: a) to ascertain the uses of social media in academic institutions; b) to identify the challenges associated with social media use for research purposes and c) to provide experiences of social media application in selected African academic institutions. The study makes use of literature analysis in combination with personal and professional work experiences on the use of social media from librarians in four different countries. Institutional experiences of the four librarians showed that it is only Rhodes University Library that uses social media in its library, which is as a result of a formal social media strategy. For the other three universities, University of Education, Winneba Library in Ghana, Makerere University Library in Uganda and the University of Nigeria Library, the use of social media is not encouraging. They use it mostly for communication and interaction with colleagues. It was also discovered that there is no social media strategy available in these university libraries. Based on these findings, the study recommended the implementation of a social media strategy, appointment of social media librarians in these libraries, and continuing professional development of librarians to keep abreast with current trends. Web 2.0/Social Media is a new technology offering new options for African academic librarians in their research support role
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  • Date Issued: 2015

Appraising the appraisal framework: evidence from Grahamstown property advertisements

  • Authors: Beangstrom, Tracy
  • Date: 2015
  • Language: English
  • Type: text , Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10962/54744 , vital:26608
  • Description: This thesis considers how interpersonal meaning choices in property advertisements are best reflected in a context of constraint in Grahamstown, South Africa, using and appraising Martin & White’s (2005) APPRAISAL Framework. The study is comparative in two senses since the data is analysed using Martin & White’s (2005) APPRAISAL Framework and a revision to it, and property advertisements from two competing estate agencies are analysed: Remax Frontier Properties and Pam Golding Properties. An initial strict application of Martin & White’s (2005) framework is followed by a second, based on analyst difficulties and framework limitations experienced in the first analysis, as well as those experienced by other researchers. Revisions to the original framework include added ‘local’, context-driven features and sub-categories: Exclusivity and Convenience in Attitude, a Scale of Intensity in Graduation, and a category ‘Invite’ in Engagement. These enable a richer, more detailed account of the alignment strategies and interpersonal micro-politics at play in the property advertisements than is possible using the original framework. Findings from the analyses reveal four facts of note. Firstly, that while the original Martin & White (2005) APPRAISAL Framework captures a general level of interpersonal meaning in the data, it does so more fully when it includes contextual and contextually-driven categories that are informed by local knowledge. Secondly, two levels of meaning are expressed in the data. One is aimed at an ‘external’ audience; the other, truer, fuller and more contentious, is aimed at what appears to be the intended audience only. Thirdly, and relatedly, specific contextual and cultural knowledge is needed by the intended audience to access the intended meaning. Fourthly, both estate agencies promote values of high prestige, exclusivity, elitism and wealth as their intended meaning to align a like-minded audience, although Remax Frontier Properties attribute these values to location and features of the home to a greater extent than Pam Golding Properties, who place greater emphasis on the size of the home. The thesis suggests further avenues for research into the discourse of property advertising, as well as into overcoming certain context-specific limitations of the APPRAISAL Framework.
  • Full Text:
  • Date Issued: 2015

Appreciation ceremony, kwaThole

  • Authors: Unnamed
  • Date: 2015
  • Subjects: UNCATALOGUED
  • Type: Video
  • Identifier: http://hdl.handle.net/10962/302712 , vital:58235 , KHV-243
  • Description: Elder's explaining reasons for the ceremony , Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-ShareAlike" License (http://creativecommons.org/licenses/by-nc-sa/2.0/) (NEVER CAHNGE THIS FIELD)
  • Full Text: false
  • Date Issued: 2015

Appreciation ceremony, kwaThole 2

  • Authors: Unnamed
  • Date: 2015
  • Subjects: UNCATALOGUED
  • Type: Video
  • Identifier: http://hdl.handle.net/10962/302859 , vital:58255 , KHV-244
  • Description: Elder's explaining reasons for the ceremony , Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-ShareAlike" License (http://creativecommons.org/licenses/by-nc-sa/2.0/) (NEVER CAHNGE THIS FIELD)
  • Full Text: false
  • Date Issued: 2015

Approaches in the prioritisation of areas for biodiversity conservation: a case study from the Western Cape pf South Africa

  • Authors: Southey, Phillippa Kate
  • Date: 2015
  • Subjects: Biodiversity conservation -- South Africa -- Western Cape , Conservation of natural resources -- South Africa -- Western Cape
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10948/4122 , vital:20548
  • Description: Historical ad hoc allocations of land for biodiversity conservation have led to a biased representation of habitat within the Cape Floristic Region, with Protected Areas concentrated in upland areas at high altitudes and on steep slopes. The field of Conservation Planning developed to ensure that allocations of areas to Protected status no longer result in such bias and rather promotes the persistence of biodiversity. This study reviewed a recent allocation of land to biodiversity conservation within Western Cape of South Africa, using both a quantitative and qualitative approach, to determine their value to biodiversity conservation. The area was previously used for commercial forestry but now has been allocated to conservation land-uses. The allocation was based on the area’s value to the forestry industry. The qualitative approach in this study engaged with relevant stakeholder groups to map priority areas, while the quantitative approach used available data on biodiversity features to map priority areas. Neither approach determined that the area allocated is in its full extent a priority for biodiversity conservation. This indicated that in the current era of Conservation Planning, Protected Areas are still being allocated in an ad hoc manner, as a result of their limited perceived benefit to anthropocentric needs. The future allocation of land to biodiversity conservation should rather integrate expert knowledge and available quantifiable data to ensure that priority areas for biodiversity conservation are being protected.
  • Full Text:
  • Date Issued: 2015

Aquatic invasions of the Nseleni River system: causes, consequences and control

  • Authors: Jones, Roy William
  • Date: 2015
  • Subjects: Gastropoda -- South Africa , Introduced snails -- South Africa , Introduced mollusks -- South Africa , Loricariidae , Introduced fishes -- South Africa , Water hyacinth , Alien plants -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5928 , http://hdl.handle.net/10962/d1017806
  • Description: Globalization has seen an unprecedented dispersal of exotic and alien species worldwide resulting in worldwide homogenization and sometimes extinction of indigenous or endemic taxa. When an exotic species becomes established in a new habitat the invasive organisms are capable of having an impact on indigenous community dynamics and the overall structure and function of ecosystems. Furthermore, the impact of invasion is determined by the geographical range, abundance and the per-capita or per-biomass effect of the invader. However, the success of the introduced organisms is reliant on their ability to acclimate to the physiochemical conditions of the newly invaded environment.Freshwater ecosystems are especially vulnerable to invasions because there are numerous potential routes of introduction including intentional pathways such as stocking, and unintentional pathways such as the release of ballast water and aquarium releases. Efforts to limit the introduction of invasive species or to manage established exotic populations are often hindered by insufficient understanding of the natural history of problematic species. Relatively little is known regarding the physiological tolerances of many taxa. Knowledge about specific species ecophysiological constraints allows for the prediction of future patterns of invasion more accurately, including where an introduced organism would probably survive, thrive and disperse. Furthermore, data on the physiological tolerances of an introduced exotic organism may provide data necessary for effective management and control. This studyinvestigated three invasive species in the Nseleni River system in a protected area in KwaZulu-Natal. The species studied were, Tarebia granifera (Quilted melania – Lamarck, 1822), Pterygoplichthys disjunctivus (Suckermouth armoured catfish - Weber, 1991) and Eichhornia crassipes (water hyacinth – (Martius) Solms-Laubach,). The Nseleni River flows into Lake Nsezi which is responsible for providing potable water to the surrounding towns and industry, as well as the surrounding rural communities. The Enseleni Nature reserve has become the centre for biodiversity dispersal in the immediate area, due to the change in landscape surrounding the protected area.An important step in developing alien invasive species management strategies in protected areas is determining their extent and invasive traits. Tarebia granifera is a prosobranch gastropod originally from South-East Asia that has become invasive in several countries around the world including South Africa. Snail populations were sampled at nine sites throughout the Nseleni/Mposa river system every six weeks over a twelve month period. The snail was abundant throughout the system, especially in shallow waters of less than 1m in depth.The first positive identification the loricariid catfish Pterygoplichthys disjunctivus for the Nseleni River was in 2006. The original introduction is believed to have been via the aquarium trade. The aim of the study was to assess the usefulness of the unified framework with regard to management of fish invasions by assessing the invasion stage of the loricariid population and identifying appropriate management actions using the Blackburn et al. (2011) framework. The fish were sampled at nine different sites and three different depths over a period of twelve months, as well as when two ichthyological surveys were carried out on the Nseleni River system. This invasive fish has been located throughout the system and both male and female fish were collected. The smallest fish sampled was a fingerling of a day or two old and the smallest pregnant female was a mere 270mm TL. This is a clear indication that this fish is breeding in the river system.Although T. granifera and P. disjunctivus were abundant in the Nseleni/Mposa river system, it was not clear what their role in the system was, and in particular if they were competing with any of the indigenous species. Therefore, isotope samples were collected from numerous taxa over a two week period, with the exception of Pterygoplichthys disjunctivus samples, which were collected over 12 months. The δ13C and δ15N signatures of all samples were determined. The niche overlap between the invasive and indigenous snails was effectively zero (1.02E-13%), indicating no shared food resources. The medium ranges of dNRb (7.14) and dCRb (9.07) for the invasive fish indicate that it utilizes a wider range of food resources and trophic levels than the majority of indigenous fish. A medium CDb value (2.34) for the invasive fish species, P. disjunctivus, describes medium trophic diversity, with three indigenous species possessing higher diversity and three possessing lower diversity. Furtherresults indicated that there was no direct dietary competition between P. disjunctivus and indigenous species. Eichhornia crassipes was first recorded on the Nseleni River in 1978, and has been shown to have a significant negative impact on the biodiversity of the Nseleni/Mposa River system and therefore required a control intervention. Although biological control using the two weevil species Neochetina eichhornia (Warner) and N. bruchi (Hustache) has been credited with affecting a good level of control, the lack of a manipulated post-release evaluation experiments has undermined this statement. Five experimental plots of water hyacinth of 20m2 were sprayed with an insecticide to control weevils. After ten months the plants in the sprayed plots were significantly bigger and heavier than those in the control plots that had natural populations of the biological control agents. This study has shown unequivocally that biological control has contributed significantly to the control of water hyacinth on the Nseleni/Mposa River system.The management plan for the Enseleni Nature Reserve identifies the need to control invasive and/or exotic organisms within the boundary of the protected area. In addition, set guidelines have been implemented on how to control these organisms, so that indigenous organisms are least affected. Lack of control of exotic organisms can have serious consequences for indigenous species. It is therefore of utmost importance that the population dynamics of the invading organism be understood, what the potential impact could be and how to control them. Furthermore, it has also acknowledged the threat of possible exotic species invasions from outside of the protected area that might result in threats to the protected area and that these must be investigated, researched and managed.This thesis has identified Tarebia granifera, Pterygoplichthys disjunctivus and Eichhornia crassipes as being a threat to indigenous biodiversity within the protected area, as well as in adjacent areas to the protected area. The thesis will therefore investigate the hypothesis that both Tarebia granifera and Pterygoplichthys disjunctivus are having a direct negative effect on available food resources for indigenous species of organisms. In addition, this thesis will investigate if theNeochetina species that have previously been introduced onto E. crassipes are having any negative effect on this invasive alien aquatic plant.
  • Full Text:
  • Date Issued: 2015

Art investment as a portfolio diversification strategy in South Africa

  • Authors: Botha, Ferdi , Scott, Brett , Snowball, Jeanette D
  • Date: 2015
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/67422 , vital:29086
  • Description: publisher version , Art has been suggested as a good way to diversify investment portfolios during times of financial uncertainty. The argument is that art exhibits different risk and return characteristics to conventional investments in other asset classes. The new Citadel Art Price index offered the opportunity to test this theory in the South African context. The Citadel index uses the hedonic regression method with observations drawn from the top 100, 50 and 20 artists by sales volume, giving approximately 29 503 total auction observations. The Index consists of quarterly data from the period 2000Q1 to 2013Q3. A VAR of the art price index, Johannesburg Stock Exchange all-share index, house price index, and South African government bond index were used. Flowing from the VAR results, additional analyses included variance decomposition, impulse response, and, to determine volatility, variance and standard deviation measures for each index. Results show that, when there are increased returns on the stock market in the previous period and wealth increases, there is a change in the Citadel Art Price Index in the same direction. This finding is consistent with Goetzmann et al. (2009), who reported that there is a strong relationship between art and equity markets and that art price changes are driven by capital gains and losses. No significant difference was found between the house price index and the art price index, and neither between the art and government bond price indices. Overall, the South African art market does not offer the opportunity to diversify portfolios dominated by either property, bonds, or shares.
  • Full Text:
  • Date Issued: 2015
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