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Omics-based molecular techniques in oral pathology centred cancer: prospect and challenges in Africa

  • Authors: Adeola, Henry A. , Soyele, Olujide.O. , Adefuye, Anthonio O. , Jimoh, Sikiru A. , Butali, Azeez
  • Date: 2017
  • Subjects: Eastern Cape, South Africa Oral mucosa--Cancer Oral Pathology Cancer Computer File
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/11260/5857 , vital:44658 , https://DOI10.1186/s12935-017-0432-8
  • Description: Background:The completion of the human genome project and the accomplished milestones in the human proteome project; as well as the progress made so far in computational bioinformatics and “big data” processing have contributed immensely to individualized/personalized medicine in the developed world.Main body:At the dawn of precision medicine, various omics-based therapies and bioengineering can now be applied accurately for the diagnosis, prognosis, treatment, and risk stratification of cancer in a manner that was hitherto not thought possible. The widespread introduction of genomics and other omics-based approaches into the postgraduate training curriculum of diverse medical and dental specialties, including pathology has improved the proficiency of practitioners in the use of novel molecular signatures in patient management. In addition, intricate details about disease disparity among different human populations are beginning to emerge. This would facilitate the use of tailor-made novel theranostic methods based on emerging molecular evidences.Conclusion:In this review, we examined the challenges and prospects of using currently available omics-based technologies vis-à-vis oral pathology as well as prompt cancer diagnosis and treatment in a resource limited setting.Keywords:Omics-based, Molecular, Developing world, Oral pathology, Challenges
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  • Date Issued: 2017

On the sensitivity of thermally and optically stimulated luminescence of α-Al2O3: C and α-Al2O3: C, Mg

  • Authors: Kalita, Jitumani M , Chithambo, Makaiko L
  • Date: 2017
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/119803 , vital:34784 , https://doi.org/10.1016/j.radmeas.2017.03.006
  • Description: The luminescence sensitivity of α-Al2O3:C and α-Al2O3:C, Mg is of interest because of the contemporary use of these materials in dosimetry related applications. We report investigations concerning the change in sensitivity of thermoluminescence (TL) and optically stimulated luminescence (OSL) from α-Al2O3:C and α-Al2O3:C, Mg with re-use. The study was carried out on a set of un-annealed samples and others annealed at 700 and 900 °C. The TL and OSL sensitivity in α-Al2O3:C and α-Al2O3:C, Mg was found to increase with sample re-use whether the intensity was monitored as peak area or peak height for the main TL peak or, in the case of OSL, as the maximum intensity or the area under a decay curve. The fractional increase in area under either the main TL peak or the OSL decay curve exceeds that of the TL peak height or maximum OSL intensity when samples are re-used. However, when un-annealed samples are used, any increase in TL peak height or peak area per measurement is less than observed in annealed samples. It is also interesting to note that the change in maximum OSL intensity or OSL area is minimal for samples annealed at 900 °C. In general, the TL sensitivity in α-Al2O3:C increases more than that in α-Al2O3:C, Mg with re-use. On the other hand, the OSL sensitivity in α-Al2O3:C, Mg increases more than that in α-Al2O3:C with re-use. These findings suggest that it is advisable to take into account the fractional increase in sensitivity per measurement when one uses α-Al2O3:C as a TL dosimeter and α-Al2O3:C, Mg as an OSL dosimeter.
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  • Date Issued: 2017

On the shop-floor: ten years at Ford

  • Authors: Cilibe, Mpumelelo
  • Date: 2017
  • Subjects: Creative writing (Higher education) South Africa , South African fiction (English) 21st century , Autobiographical fiction, South African (English) 21st century , Xhosa fiction 21st century , Short stories, Xhosa 21st century
  • Language: English , Xhosa
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10962/7257 , vital:21234
  • Description: My autobiographical novella covers a period of my life between 1974 and 1984, when I worked at the Ford Motor company Struandale Assembly plant in Port Elizabeth. This period predated the formation of NUMSA (the National Union of Metal Workers of South Africa) and COSATU - it was a time when automobile industry workers broke away from the race- based unions to form MACWUSA (Motor Assemblers and Component Workers Union of SA). Around the same time Rev Leon Sullivan was putting pressure on US companies, including Ford, to move away from apartheid labour practices. As quite an angry young man influenced by the Black Consciousness movement, I got deeply involved in union activities mainly for my own survival, and as a personal reaction to racism in the workplace. The story is told in a realist style, with many anecdotal detours giving the flavour of life in New Brighton in the 1980s. Important influences have been Bloke Modisane's autobiography, Blame Me on History and Studs Terkel's interviews of Ford plant workers and management in his book Working. , Growing up in New Brighton gave me so many stories that had never been written before but that were told person to person by the residents of my neighbourhood. Some of the tales in this collection are based on such stories. Others are stories that are reminiscent of childhood while growing up with an elder brother. I take the inspiration from different books that are in line with the stories that I am writing: collections of Extreme Fiction - Fabulists and Formalists that were edited by Robin Hemley and Michael Martone and The Best Bizarro Fiction of the Decade edited by Jeremy Robert Johnson and Cameron Pierce. Some stories by L.L. Ngewu and L.S. Ngcangata, and a novellette by P.T. Mtuze, Alitshoni Lingaphumi, also bring much influence as they reveal suffering in the lives of black people who endured forced removals, and other situations that are of interest to build my stories on. , Le ngqokolela yamabali iqulathe amabali asekelwe kumabali endandiweva ebaliswa ebuntwaneni bam ndisakhula. Amanye amabali angeenkumbulo zasebuntwaneni ngethuba ndandikhula nomkhuluwa wam ongasaphiliyo. Ifuthe lokuwaqamba ndilifumene kwiincwadi zababhali abanje ngabo bafumaneka kwiingqokolela ezihlelwe nguRobin Hemley no Michael Martone kwincwadi ethi Extreme Fiction - Fabulists and Formalists, noJeremy Robert Johnson enoCameron Pierce kwingqokolela ethi, The Best Bizarro Fiction of the Decade. Amanye amabali abenefuthe ndiwafumene kwiincwadi zooP.T. Mtuze, kwinovella yakhe ethi Alitshoni Lingaphumi, nakwezoL.L. Ngewu noL.S. Ngcangatha apho babalisa ngobomi basekuhlaleni ngexesha abantu babedudulwa befuduswa ngetshova ukususwa kwiindawo zabo zokuhlala. , This thesis is presented in two parts: English and isiXhosa
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  • Date Issued: 2017

One size does not fit all: critical insights for effective community-based resource management in Melanesia

  • Authors: Aswani, Shankar , Albert, Simon , Love, Mark
  • Date: 2017
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/145392 , vital:38434 , DOI: 10.1016/j.marpol.2017.03.041
  • Description: In recent years, Fiji's approach of combining traditional systems of community-based coastal management and modern management systems has become a successful blueprint for marine conservation, particularly the Locally Managed Marine Area (LMMA) network model. As a result of this success, conservation practitioners have imported the Fiji LMMA model to the Solomon Islands and in Vanuatu in hope of replicating the purported success attained in Fiji. This paper argues that because tenure systems and associated political systems in Fiji, the Solomon Islands, and Vanuatu are substantially different, one cannot simply extrapolate the more centralized tenurial and political Fiji model to the decentralized tenurial and politically eclectic Solomons and Vanuatu. This paper provides an analysis of some of the various approaches used in these countries to make a case for why socio-political diversity and historical particulars matter to resource management and conservation-in-practice (and for any development interventions).
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  • Date Issued: 2017

Online consumers’ product purchasing behaviour, advertising and involvement in fashion consumption in South Africa

  • Authors: De Vos, Tania
  • Date: 2017
  • Subjects: Electronic commerce Retail trade -- South Africa -- Management , Purchasing Consumer behavior -- South Africa Clothing trade -- South Africa
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: http://hdl.handle.net/10948/46295 , vital:39544
  • Description: While store-based fashion retailing continues to be the prevailing channel for South Africans, the country’s consumers are increasingly engaging with products online. It should be noted that online fashion purchasing behaviour does not necessarily follow the traditional consumer behaviour of the brick-and-mortar retailing environment. Therefore, ecommerce organisations are required to investigate the determinants of customer online shopping engagement among their market segments. With an improved understanding of the consumer’s online purchase behaviour, pure-play fashion retailers can create useful and successful online shopping strategies to attract new and potential customers. Thus, the future market for this industry as well as factors influencing online behaviour must be investigated and improved upon. This research study aimed to present a general overview and analysis of how online fashion consumption can grow and be sustainable in South Africa. This was accomplished by identifying various key factors contributing toward online fashion consumption and purchasing behaviour, in creating an attractive online shopping environment, whilst generating more customers, building customer loyalty and increasing competitiveness. As in any retail business, customer satisfaction is the key component for online fashion success. The purpose of this study was to execute a novel assessment of online consumers’ product purchasing behaviour, as well as advertising and involvement in fashion consumption in the South African context. To achieve this purpose, an in-depth literature review and a positivistic research investigation were conducted. The selected method was the most appropriate approach to achieve the research objectives by answering the research questions as well as to test the proposed hypotheses in relation to The Perceived Success of Online Fashion Consumption (dependant variables). As mentioned, the study involved a deductive approach of the positivistic paradigm to identify online purchasing motivation and factors that can assist with indicating what the pure-play fashion interface needs to deliver to stay competitive and increase market presence. This research study is considerably valuable as data from 16087 respondents from the participating pure-play fashion retailer have been recorded and the results indicated that the proposed hypotheses were all supported, thus reporting a significant relationship and positive influence on the perceived success of online fashion consumption.
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  • Date Issued: 2017

Online mentoring as a transformative tool for female career and business development

  • Authors: Oosthuizen, Nadine
  • Date: 2017
  • Subjects: Mentoring in business -- South Africa Glass ceiling (Employment discrimination) -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/20510 , vital:29301
  • Description: The under-representation of females at management level due to the glass ceiling effect has globally received considerable attention. Research found that one of the remedies for females to progress beyond the glass ceiling, was access to a mentor in senior management. Females receiving mentoring in the workplace perform at greater levels as they gain reflected power, advise and the right to use essential resources. Yet, access to mentors was recognised as a barrier to females’ professional career success, both in the corporate field and to develop their small businesses. Fortunately, the revolution in technology has led to online mentoring which combines conventional mentoring relationship approaches with new technology and provides wider access to a pool of mentors. The increasing popularity of online mentoring can be attributed to the benefits it offers stereotyped individuals and those from marginalised groups. The purpose of this study therefore was to ascertain the enabling conditions necessary for effective online mentoring in South Africa, as well as how it can be used to develop the careers of females (both corporate employees and small business entrepreneurs). The study followed a mixed method approach with a sequential exploratory design. Background literature on conventional mentoring in addition to oniline mentoring assisted in contextualising the many issues relating to conventional mentoring which also apply to online mentoring. Primary data was collected in three phases (two qualitative and one quantitative). The data collection method for phases one and two of the enquiry was interviews with the use of a semi-structured interview schedule and for phase three, a survey via an online structured questionnaire. The biographical profiles of the participants interviewed during phases one and two were presented as case studies. Based on the content analysis of the qualitative interviews with five South African mentors, six female mentees from Africa, two South African online mentoring field specialists and one United States online mentoring field specialist, three main themes were identified viz. online mentoring processes, challenges and enabling conditions. Online mentoring processes identified for effective online mentoring related to the application-, selection-, matching- and conflict resolution procedures. Mentoring challenges related to matching preferences, technology impediments, cultural fit problems, language differences, lack of mutual trust, scheduling and frequency and duration of meetings, the impersonal nature of online mentoring and specific mentee- and mentor-related challenges. Based on the content analysis, the conditions for creating an effective online mentoring environment addressed some of the challenges alluded to and could be classified as generic, mentee-specific and mentor-specific enablers. Generic online mentoring enablers are those conditions necessary for creating an effective online mentoring environment for the mentoring pair such as the ability to establish a trusting relationship, flexible meeting schedules, training offered, the expression of emotions online, having a technology infrastructure in place, clear objectives and relationship boundaries, a desirable programme- and meeting duration with adequate meetings, using multiple contact methods and following a hybrid mentoring approach. Mentor specific issues to create an effective online mentoring environment are mentors with exceptional personal qualities that are knowledgable and experienced, while mentee specific issues relate to continuous mentee commitment and that mentees should have been previously exposed to mentoring. The constant comparative data analysis provided insight into how similar or dissimilar institutions approach online mentoring process and the challenges related to the local (South African) online mentoring environment as compared to those globally. Sixty-three respondents (South African mentors both male and female and female mentees who have undergone conventional mentoring) completed the online structured questionnaire on their perceptions of the online mentoring conditions necessary for effective online mentoring. From the exploratory factor analysis results of the online survey in phase three of the study, six valid and reliable conditions necessary for online mentoring were identified namely, infrastructure readiness, demographic matching preference, mentor characteristics, the communication process, mentoring pair perceptions and mentoring pair relationship. The multiple regression analysis performed established one statistically significant relationship. The perception that the mentoring pair hold of online mentoring influence the achievements of the mentee. This study has thus identified several conditions necessary for effective online mentoring globally, as well as for South Africa. South Africa has a pool of knowledgeable mentors involved in global online mentoring progammes and they can assist with online mentoring in the South African communities in need of assistance. However, South Africa can learn from well-established global online mentoring institutions how to implement an effective online mentoring programme, but will need the necessary financial resources to do so. This study further provided evidence on how online mentoring can be utilised for the career advancement of female corporate employees and those owning small businesses. Some guidelines were provided on how to overcome the various challenges associated with online mentoring globally, and those specific to South Africa. The use of mobile technology instead of computer-mediated technology was recommended as it provides greater access to online mentoring, especially for rural communities. It is also more user-friendly for those with limited computer technology skills.
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  • Date Issued: 2017

Optical fibre measurement for clock tones in telescope networks

  • Authors: Dlamini, Phumla Patience
  • Date: 2017
  • Subjects: Fiber optics Very large array telescopes
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10948/22200 , vital:29872
  • Description: Astronomy dates back to the early man’s impression of the heavens with little information recorded including some drawings of comets, eclipse and supernovas[1]. Major progress has been made in the field of Astronomy since then. Scientific curiosity to probe the universe in attempt to answer questions such as the origin of the universe, the matter it is made of, the formation of stars, planets and galaxies, and tracking life in other solar systems has brought about the need for more advanced tools capable of detailed observations. In 1608 H. Lippershey developed the first refracting telescope[2], [3]. A year later Galileo used a similar telescope pointing skywards discovering mountains and craters on the earth’s moon, the moons of Jupiter and the phases of Venus. Over the years telescopes have been developed with advancements from the optical telescope towards much larger and more sensitive radio telescopes. The first radio signal from space was detected by Karl Jansky and ever since then astronomers have been using radio telescopes to explore the universe by detecting radio waves emitted by cosmic objects[4]. The ability of radio telescopes to detect weak signals is related to the signal capture surface. As the demand for sensitivity, transmission bandwidth and data rate increases, so does the need for telescopes with a large field of view and capability to observe different parts of the sky at once[5]. This is possible with radio telescope array, with the data from the antennas combined electronically to produce a high resolution image of the sky. The South African MeerKAT radio telescope is an array of 64 interlinked antennas each transmitting up to 160 Gbps of data to the central processing site over optical fibre which is ideal for carrying large volumes of data at high speeds. The MeerKAT telescope is a precursor to the Square kilometer Array which will have up to 50 times the sensitivity and 10000 times the survey speed than the best telescope[6].
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  • Date Issued: 2017

Optical limiters with improved performance based on nanoconjugates of thiol substituted phthalocyanine with CdSe quantum dots and Ag nanoparticles

  • Authors: Oluwole, David O , Yagodin, Alexey V , Britton, Jonathan , Martynov, Alexander G , Gorbunova, Yulia G , Tsivadze, Aslan Yu , Nyokong, Tebello
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/238286 , vital:50605 , xlink:href="https://doi.org/10.1039/C7DT03867D"
  • Description: Two alternative synthetic approaches affording a low-symmetry A3B-type phthalocyanine 1 bearing two [2′-(2′′-mercaptoethoxy)ethoxy] anchoring substituents were developed. Due to the presence of thiol groups, this phthalocyanine could be conjugated with TOPO-capped (TOPO - trioctylphosphine)-capped CdSe quantum dots (CdSe-QDs) or oleylamine capped silver nanoparticles (Ag-NPs). The nonlinear optical behaviour of starting phthalocyanine, quantum dots, nanoparticles and their conjugates was studied by using an open aperture Z-scan technique, revealing that the grafting of 1 onto the nanomaterials resulted in a significant enhancement of the optical limiting of 1-Ag and 1-CdSe in comparison with the individual components. The conjugate 1-CdSe, being the first example of Pc-based thiol conjugated with quantum dots, revealed superior limiting characteristics with a limiting threshold below 0.18 J cm−2.
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  • Date Issued: 2017

Optical limiting properties of 2, 6-dibromo-3, 5-distyrylBODIPY dyes at 532 nm

  • Authors: Kubheka, Gugu , Mack, John , Kobayashi, Nagao , Kimura, Mitsumi , Nyokong, Tebello
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/190405 , vital:44991 , xlink:href="https://doi.org/10.1142/S1088424617500511"
  • Description: Optical limiting properties of 2,6-dibromo-3,5-distyrylBODIPY dyes were investigated by using the z-scan technique at 532 nm in the nanosecond pulse range. A strong reverse saturable absorption response was observed even in solution, which suggests that compounds of this type are potentially suitable for use in optical limiting applications.
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  • Date Issued: 2017

Optical limiting properties of 3, 5-diphenyldibenzo-azaBODIPY at 532 nm

  • Authors: Kubheka, Gugu , Achadu, Ojodomo J , Mack, John , Nyokong, Tebello
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/232761 , vital:50022 , xlink:href="https://doi.org/10.1039/C7NJ01503H"
  • Description: Optical limiting properties of 3,5-diphenyldibenzo-azaBODIPY were investigated by using the z-scan technique at 532 nm in the nanosecond pulse range and a strong reverse saturable absorption (RSA) response was observed, which can be readily attributed to a two-photon absorption (TPA) assisted excited state absorption (ESA) mechanism in the singlet manifold based on a consideration of the other photophysical properties. The effect of solvent and incorporation into polymer thin films has been investigated in depth. The results indicate that the selection of solvents that enhance the population of the S1 excited state on the nanosecond timescale or embedding the azaBODIPY dye into polymer thin films significantly improves the optical limiting properties.
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  • Date Issued: 2017

Optical Limiting Properties of 3, 5-Dithienylenevinylene BODIPY Dyes at 532 nm

  • Authors: Harris, Jessica , Gai, Lizhi , Kubheka, Gugu , Mack, John , Nyokong, Tebello , Shen, Zhen
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/189274 , vital:44833 , xlink:href="https://doi.org/10.1002/chem.201702503"
  • Description: The optical limiting properties of a series of near infrared absorbing 3,5-dithienylenevinylene BODIPY (borondipyrromethene) dyes (1–3) that contain donor and acceptor moieties in their p-conjugation systems were studied by using the z-scan technique at 532 nm in the nanosecond pulse range. A strong reverse saturable absorption response was observed when the compounds are embedded into poly(bisphenol carbonate A) polymer thin films, which demonstrates that BODIPY dyes with this type of structure are suitable for use in optical limiting applications.
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  • Date Issued: 2017

Optimal cycle dating of large financial time series

  • Authors: Kapp, Konrad Phillip
  • Date: 2017
  • Subjects: Computer algorithms
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10948/17767 , vital:28452
  • Description: The study of cycles in the context of economic time series has been active for many decades, if not centuries; however, it was only in recent decades that more formal approaches for identifying cycles have been developed. Litvine and Bismans (2015) proposed a new approach for dating cycles in financial time series, for purposes of optimising buysell strategies. In this approach, cycle dating is presented as an optimisation problem. They also introduced a method for optimising this problem, known as the hierarchical method (using full evaluation 2, or HR-FE2). However, this method may be impractical for large data sets as it may require unacceptably long computation time. In this study, new procedures that date cycles using the approach proposed by Litvine and Bismans (2015), were introduced, and were speciffically developed to be feasible for large time series data sets. These procedures are the stochastic generation and adaptation (SGA), buy-sell adapted Extrema importance identity sequence retrieval (BSA-EIISR) and buysell adapted bottom-up (BSA-BU) methods. An existing optimisation technique, known as particle swarm optimisation (PSO), was also employed. A statistical comparison was then made between these methods, including HR-FE2. This involved evaluating, on simulated data, the performance of the algorithms in terms of objective function value and computation time on different time series lengths, Hurst exponent, and number of buy-sell points. The SRace methodology (T. Zhang, Georgiopoulos, and Anagnostopoulos 2013) was then applied to these results in order to determine the most effcient methods. It was determined that, statistically, SGA, BSA-EIISR and BSA-BU are the most effcient methods. Number of buysell points was found to have the largest effect on relative performance of these methods. In some cases, the Hurst exponent also has a small effect on relative performance.
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  • Date Issued: 2017

Optimisation of a mini horizontal axis wind turbine to increase energy yield during short duration wind variations

  • Authors: Poole, Sean Nichola
  • Date: 2017
  • Subjects: Wind turbines -- Design and construction , Horizontal axis wind turbines -- Blades , Wind turbines -- Aerodynamics , Wind power
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/7036 , vital:21196
  • Description: The typical methodology for analytically designing a wind turbine blade is by means of blade element momentum (BEM) theory, whereby the aerofoil angle of attack is optimized to achieve a maximum lift-to-drag ratio. This research aims to show that an alternative optimisation methodology could yield better results, especially in gusty and turbulent wind conditions. This alternative method looks at increasing the aerofoil Reynolds number by increasing the aerofoil chord length. The increased Reynolds number generally increases the e_ectiveness of the aerofoil which would result in a higher or similar lift-to-drag ratio (even at the decreased angle of attacked require to maintain the turbine thrust coe_cient). The bene_t of this design is a atter power curve which causes the turbine to be less sensitive to uctuating winds. Also, the turbine has more torque at startup, allowing for operatation in lower wind speeds. This research is assumed to only be applicable to small wind turbines which operated in a low Reynolds number regime (<500 000), where Reynolds number manipulation is most advantageous.
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  • Date Issued: 2017

Optimising syzygium cordatum dye extraction and subsequent cotton dyeing incorporating organic electrolytes

  • Authors: Gamedze, Nombuso Faith
  • Date: 2017
  • Subjects: Dyes and dyeing -- Cotton Syzygium cordatum
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10948/19509 , vital:28888
  • Description: The present investigation was carried out to optimize the extraction of natural dye from Syzygium cordatum,bark trees and then to evaluate its use in the dyeing of cotton fabric incorporating organic electrolyte. The bark was collected from recently fallen trees and twigs pruned from old trees, since they have greater dye content than the younger trees, dried for two weeks, crushed with a hammer and ground into powder. Grinding of bark was done to ensure a uniform particle size with a large surface area to facilitate quick extraction. The relevant conditions for natural dye extraction using a methanol/water mixture were optimized by Response Surface Methodology (RSM), with the help of Design Expert Version 7.0. The central composite design (CCD) was applied to design experiments for the evaluation of the interactive effects of the three most important operating extracting variables namely, temperature, time and liquor volume on 25g bark powder. This approach decreased the required number of experiments, and the following optimized extraction conditions were derived; temperature 700C, time 51minutes and material-to-liquor ratio 1:16. Dye used for subsequent dyeing was extracted using the optimized conditions. To determine the best conditions for dyeing cotton fabric with the dye extract, dyeing was carried out in a rotating canister machine, using two different organic electrolytes, namely trisodium nitrilo triacetate (trisodium NTA) and dimethylformamide, as mordants. The use of organic electrolytes, as mordants, was to ensure eco-friendliness of the dyeing, and with a maximum concentration of 3g/L being used to reduce the effluent load. Three different mordanting techniques, namely simultaneous, pre-mordanting and post-mordanting were investigated so as to establish which is best. The impact of the two organic electrolyte mordants on certain physical properties of the cotton fabric was also determined. The dyeing of cotton with theSyzygium cordatum bark dye extract, in conjuction with an organic electrolyte, generally showed good results, with trisodium NTA superior to dimethylformamide as a mordant. An increase in trisodium NTA mordant concentration increased dye exhaustion and a dye exhaustion of 23.7% being achieved with 3g/L pre-mordanting. This is still relatively low, however, and the use of an exhausting agent needs to be explored. The fabric dyed with a mordant, exhibited good wash, rub and perspiration fastness, with trisodium NTA superior to dimethylformamide. The use of trisodium NTA increased the strength of the dyed fabric whereas the use of dimethylformamide decreased it. In general, pre- and simultaneous mordants were better than post-mordanting. It has been shown that the dyeing of cotton, using Syzygium cordatum bark dye extract, in conjuction with an organic electrolyte, particulary trisodium NTA, has potential and can be recommended for craft applications. Optimised conditions for dye extraction and cotton dyeing have been derived and which can be recommended for use by crafters in Swaziland.
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  • Date Issued: 2017

Optimization of flexible spectrum in optical transport networks

  • Authors: Boiyo, Duncan Kiboi , Gamatham, Romeo
  • Date: 2017
  • Subjects: Digital communications Optical fiber communication , Optical communications Fiber optics
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/14609 , vital:27803
  • Description: The ever-increasing demand for broadband services by end-user devices utilising 3G/4G/LTE and the projected 5G in the last mile will require sustaining broadband supply from fibre-linked terminals. The eventual outcome of the high demand for broadband is strained optical and electronic devices. The backbone optical fibre transport systems and techniques such as dense wavelength division multiplexing (DWDM), higher modulation formats, coherent detection and signal amplification have increased both fibre capacity and spectrum efficiency. A major challenge to fibre capacity and spectrum efficiency is fibre-faults and optical impairments, network management, routing and wavelength assignment (RWA). In this study, DWDM and flexible spectrum techniques such as wavelength assignment and adjustment, wavelength conversion and switching, optical add and drop multiplexing (OADM) and bitrate variable transmission have been experimentally optimized in a laboratory testbed for short- and long-haul optical fibre networks. This work starts by experimentally optimising different transmitters, fibre-types and receivers suitable for implementing cost effective and energy efficient flexible spectrum networks. Vertical cavity surface-emitting lasers (VCSELs) and distributed feedback (DFB) lasers have been studied to provide up to 10 Gb/s per channel in 1310 nm and 1550 nm transmission windows. VCSELs provide wavelength assignment and adjustment. This work utilises the non-return-to-zero (NRZ) on-off keying (OOK) modulation technique and direct detection due to their cost and simplicity. By using positive intrinsic negative (PIN) photo-receivers with error-free BER sensitivity of -18±1 dBm at the acceptable 10-9-bit error rate (BER) threshold level, unamplified transmission distances between 6 km and 76 km have been demonstrated using G.652 and G.655 single mode fibres (SMFs). For the first time, an all optical VCSEL to VCSEL wavelength conversion, switching, transmission at the 1550 nm window and BER evaluation of a NRZ data signal is experimentally demonstrated. With VCSEL wavelength conversion and switching, wavelength adjustments to a spectrum width of 4.8 nm (600 GHz) can be achieved to provide alternative routes to signals when fibre-cuts and wavelength collision occurs therefore enhancing signal continuity. This work also demonstrates a technique of removing and adding a wavelength in a bundle of DWDM and flexible channels using an OADM. This has been implemented using a VCSEL and a fibre Bragg grating (FBG) providing a wavelength isolation ratio of 31.4 dB and ~0.3 𝑑𝐵 add/drop penalty of 8.5 Gb/s signal. As a result, an OADM improves spectrum efficiency by offering wavelength re-use. Optical impairments such as crosstalk, chromatic dispersion (CD) and effects of polarization mode dispersion (PMD) have been experimentally investigated and mitigated. This work showed that crosstalk penalty increased with fibre-length, bitrate, interfering signal power and reduced channel spacing and as a result, a crosstalk-penalty trade-off is required. Effects of CD on a transmitted 10 Gb/s signal were also investigated and its mitigation techniques used to increase the fibre-reach. This work uses the negative dispersion fibres to mitigate the accumulated dispersion over the distance of transmission. A 5 dB sensitivity improvement is reported for an unamplified 76 km using DFB transmitters and combination of NZDSF true-wave reduced slope (TW-RS) and submarine reduced slope (TW-SRS) with + and – dispersion coefficients respectively. We have also demonstrated up to 52 km 10 Gb/s per channel VCSEL-based transmission and reduced net dispersion. Experimental demonstration of forward Raman amplification has achieved a 4.7 dB on-off gain distributed over a 4.8 nm spectral width and a 1.7 dB improvement of receiver sensitivity in Raman-aided 10 Gb/s per wavelength VCSEL transmission. Finally, 4.25-10 Gb/s PON-based point to point (P2P) and point to multipoint (P2MP) broadcast transmission have been experimentally demonstrated. A 10 Gb/s with a 1:8 passive splitter incurred a 3.7 dB penalty for a 24.7 km fibre-link. In summary, this work has demonstrated cost effective and energy efficient potential flexible spectrum techniques for high speed signal transmission. With the optimized network parameters, flexible spectrum is therefore relevant in short-reach, metro-access and long-haul applications for national broadband networks and the Square Kilometre Array (SKA) fibre-based signal and data transmission.
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  • Date Issued: 2017

Our turn to eat?: an Interrogation of South African media discourse on allocation of value through cadre deployment

  • Authors: Mpapela, Vuyo
  • Date: 2017
  • Subjects: Mass media -- Political aspects -- South Africa Democracy -- South Africa -- Communication , Communication in politics -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10948/19179 , vital:28781
  • Description: South Africa‟s liberal democratic constitution allows for political competition for office, enhanced by the media‟s involvement or role, as both stakeholder and facilitator for debate between the public and political parties. The role of the media becomes a sensitive one as it entails perspectives on the political process and, as a consequence, certain perceptions of the political class, structures and electoral process will emerge. In previous elections the media has been cited for abdicating its objective stance in the narrative on political competition in view of candidate lists, party coalitions and allocation of value through cadre deployment, a term used for political appointments within party structures to positions of leadership in public office. Accordingly, it provokes intense debates in which the rationality of liberal-objective-observer to democratic process is criticized by thinking which argues that such rationality remains trapped by a devotion to „liberalist rituals‟, rituals detached from embedded meanings specific to South Africa‟s socio-political dynamics.
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  • Date Issued: 2017

Outcome and impact assessment in the comprehensive evaluation of rural ICT projects in developing countries

  • Authors: Mtkoko, Hafeni Tulimewawa Wilhelmina Lyatenda
  • Date: 2017
  • Subjects: Uncatalogued
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10962/64483 , vital:28548 , DOI 10.21504/10962/64483
  • Description: Despite existing literature that indicates that Information and communication technologies (ICTs) act as tools for social change and development, there is still limited empirical evidence that demonstrates this. An outcome and impact assessment based on a comprehensive (holistic) evaluation is deemed appropriate at a time when many ICT4D programmes fail to effectively demonstrate their impact towards rural development. A comprehensive evaluation is one that incorporates the evaluation of the need, design, implementation, outcome and impact, efficiency, and scalability of a programme. These stages make up the different domains of an evaluation lifecycle. The following study aims to develop an outcome and impact assessment framework for ICT4D programmes. It forms part of continuous research associated with the development of a rural ICT Comprehensive Evaluation framework. A theoretical approach, using Design Science and Weick’s theorizing process, was applied to investigate the development of a framework (design artefact) for outcome and impact assessment of ICT4D programmes. The theorizing process analysed existing outcome and impact assessment frameworks from social programmes, information systems/technology programmes, and ICT4D programmes. The output of the theorizing process proposes five critical themes of outcome and impact assessment of rural ICT4D programmes that should be assessed. These themes include: Strategic Value, Most Significant Change, Empowerment, Livelihoods, and Sustainability. To assess its utility, the framework was implemented in the Siyakhula Living Lab and Information and Communication Technology for Rural Education (ICT4RED) projects in South Africa. Through the application of the framework in real life ICT4D contexts, the lessons learned contributed to its revision and enhancement. The proposed framework aims to guide evaluators through the assessment of outcomes and impacts in ICT4D programmes. It provides a foundation and justification for the selected outcome and impact assessment themes that contribute to a comprehensive evaluation. An outcome and impact assessment that is informed by: baseline; needs assessment; programme theory assessment; and process assessment data, provides ICT4D evaluators and project stakeholders with meaningful outcome and impact feedback. Having such an approach to outcome and impact assessment ensures that the evaluation process is seen more holistically as part of the ICT4D project as a whole. , Thesis (PhD) -- Faculty of Commerce, Information Systems, 2017
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  • Date Issued: 2017

Overlaps and organisms: Beth Diane Armstrong’s ‘in perpetuum’

  • Authors: Mukendi, Jean-Sylvain Tshilumba
  • Date: 2017
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/147171 , vital:38599 , https://artthrob.co.za/2017/07/21/overlaps-and-organisms-beth-diane-armstrongs-in-perpetuum/
  • Description: ‘in perpetuum,’ Beth Diane Armstrong’s Young Artist Award exhibition at the National Arts Festival, draws lines of growth, visually exploring life’s continuum. At first glance the exhibition evokes a geometric organism, with lines of growth, of stagnation or of regression. Armstrong admits openly that there is a substantial insecurity that runs beneath her work. We are not looking at a final concept but a work in progress, a process of back and forth, of distance and proximity, of minimalism and monumentalism, pushing of physical and mental boundaries.
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  • Date Issued: 2017

Oxygen limitation and thermal tolerance: a comparison of pulmonate and patellogastropod limpets

  • Authors: Kankondi, Sebbi
  • Date: 2017
  • Subjects: Thermal tolerance (Physiology) , Limpets -- Physiology , Limpets -- Effect of temperature on , Oxygen consumption (Physiology)
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/7570 , vital:21274
  • Description: Since the scientific community anticipates a general change in the global climate, it has become increasingly important to develop predictive models which encompass mechanisms to generate reliable forecasts of the effects this change on ecological communities and processes. To this end, the oxygen- and capacity- limited thermal tolerance (OCLTT) theory has been developed as a link between various physiological processes, the thermal aspect of climate change and the associated shifts at different levels of biological organization. This study set out to assess the general applicability of the OCLTT theory in eurythermal pulmonate and patellogastropod limpets, whose distributions overlap on the high shore rocks of the warm temperate, south-east coast of South Africa.This was done by determining their microhabitat use, median lethal temperatures and cardiac, Arrhenius breakpoint temperatures as measures of their upper thermal tolerance limits, in both air and water. The main hypotheses of the study were that the pulmonate limpets would be more common than the patellogastropods in warmer microhabitats during low tide and would have higher thermal limits than the patellogastropods in air and vice versa in water. This was based on the assumption that the two limpet groups have different capabilities of oxygen consumption in air and water, due to differences in their respiratory organs and that this would be reflected in their thermal tolerances based on predictions made by the OCLTT. This assumption was important because oxygen consumption was not measured in this study. Previous research (e.g. Garrity, 1984), showed that a thermal stress gradient exists among rocky intertidal microhabitats. From most to least thermally stressful the gradient is horizontal surfaces> slopes> vertical surfaces> tide pools> crevices. The current study found that, while the pulmonate limpets, Siphonaria capensis and S. serrata, preferred rock pools, sloped, vertical and horizontal rock surfaces, the patellogastropod limpets, Cellana capensis and Scutellastra granularis, preferred rock pools and vertical rock surfaces. Furthermore, the pulmonate limpets were only common on horizontal rock surfaces where specific ameliorating conditions would have mitigated thermal stress there. In addition, C. capensis had similar thermal tolerance limits to the pulmonate limpets in air and the pulmonate limpets had similar and/or higher thermal tolerance limits compared to S. granularis in water. This indicates that the pulmonate limpets did not necessarily prefer warmer microhabitats than the patellogastropod limpets and that there were no differences in the collective upper thermal tolerance limits between the two limpet groups in either medium.Consequently, there was no indication from this study that an assumed superior capacity for oxygen supply translates into greater thermal tolerance and that the hypotheses based on the OCLTT were not supported. Although this was an indirect test of the OCLTT theory, I conclude that this study does not support the notion of its general applicability and that mechanisms other than those outlined by the OCLTT theory may help explain the patterns of thermal limitation observed in the current study.
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  • Date Issued: 2017

Parental management of adolescent substance abuse

  • Authors: Jarman, Lennon
  • Date: 2017
  • Subjects: Teenagers -- Substance use -- South Africa -- Port Elizabeth , Parent and child -- South Africa -- Port Elizabeth -- Psychological aspects , Substance abuse -- South Africa -- Port Elizabeth , Youth -- Drug use -- South Africa -- Port Elizabeth
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10948/17625 , vital:28402
  • Description: The incidence and consequences of adolescent substance abuse for the health and well-being of adolescents, their significant others and society at large, have become an increasing concern. The early onset of substance use further enhances the potential for addiction, thus emphasizing the need for early identification and intervention. The literature and practice observations suggest that parental management, which includes parenting practices such as parental monitoring, clear rules about substance use and the modelling of protective, constructive behaviours, protects adolescents from the onset of substance use and interrupts the adolescent’s progression to substance abuse. This qualitative study aimed to explore and describe parental management of adolescent substance abuse in the Nelson Mandela Metropole. An exploratory- descriptive and contextual research design was employed in this study. Furthermore, non-probability purposive sampling, in conjunction with snowball sampling techniques, was employed to recruit parents who have or continue to manage their adolescents (between the ages of 13-18 years) substance abuse and the associated impact that it has of on the family in the past year. Semi-structured individual interviews were conducted with ten parents, and data collection ceased upon reaching data saturation. The generated data was analysed using thematic data analysis. The trustworthiness of the research process and the findings was enriched by engaging in a variety of data verification strategies. The following main themes emerged from the data analysis process: Participants’ perspective of adolescent substance use in their community; Participants’ experiences of their own child’s substance use; Impact of substance use on the family system; Participants’ perspective of their role in managing adolescent substance use; and, Participants’ support needs in relation to adolescent substance use. The findings contribute to a greater understanding of what parents require to effectively prevent and/or manage substance abuse by their adolescent children. The findings furthermore recommend preventive interventions at both primary and secondary level.
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  • Date Issued: 2017
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