Showing items 221 - 240 of 1227

Your selections:

Analysing learning at the interface of scientific and traditional ecological knowledge in a mangrove ecosystem restoration scenario in the eastern coast of Tanzania

  • Authors: Sabai, Daniel , Sisitka, Heila
  • Date: 2013
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/127179 , vital:35974 , https://doi.org/10.2478/trser-2013-0027
  • Description: Records from community-based coastal management initiatives indicate that local communities who are key actors in activities that aim at safeguarding the health status of terrestrial and marine ecosystems face a lot of challenges associated with adapting andapplying indicators that are scientifically abstracted and methodologically too reified, given varying social, contextual and technical conditions prevailing amongst them. This paper brings into view possible challenges of adapting and applying scientific indicators in community-based monitoring of mangrove ecosystem and suggests a new approach that may lead to development of indicators which are less reified, more congruent to users (coastal communities) and likely to attract a wider social learning in the mangroverestoration context. It also sets a bridge for scientific institutions (including universities), tounderstand various social, cultural and contextual needs that determine epistemological access between them and local communities, which need to be addressed prior to engaging targetcommunities in participatory monitoring programmes.The paper attempts to analyse learning at the interface of knowledge that scientific institutions produce and the potential knowledge that exists in local context (traditional ecological knowledge) for purposes of widening and improving knowledge sharing and safeguarding the health status of mangrove species and fisheries that use them as key habitats. The paper stems from a study which employs processes of abstraction and experiential learning techniques such as Experiential Learning Intervention Workshop carried out in 2012,to unlock knowledge that local communities have, as an input for underlabouring existing scientific indicators in the eastern coast of Tanzania.It brings into view the need to consider contextual realities on ground, the level of education that the participating group has, the minimum level of participation that is required, structures that govern coastal monitoring practices at local level and the need for scientific institutions to consider the knowledge that local people have as an input for enhancing or improving coastal monitoring, especially monitoring of mangrove and fishery resources. The paper finally comes up with a framework of indicators which is regarded by coastal communities as being less reified, more contextually and culturally congruent and which can easily be used in detecting environmental trends, threats, changes and conditions of mangrove and fisheries resources, and attract wider social learning processes.
  • Full Text:
  • Date Issued: 2013

Analysis of factors influencing the performance of a hydrokinetic coil pump

  • Authors: Opperman, Adriaan Jacobus
  • Date: 2013
  • Subjects: Pumping machinery, Electric , Pumping machinery -- Performance
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:9640 , http://hdl.handle.net/10948/d1021041
  • Description: A hydrokinetic coil pump (HCP) is described by its name. It is a coil pump driven by the kinetic energy in flowing water. The hydrokinetic energy is converted into mechanical energy by means of a paddle-wheel. The coil pump makes up part of the paddle-wheel and together is called a HCP. The HCP floats in a stream of flowing water while tethered to the bank. The focus of the study was to identify and analyse the factors influencing the HCP. The HCP was then optimized for rural application. Data acquisition took place through experimentation on a full scale experimental platform according to a central composite experimental design. Variables used for the experimentation included; Stream Velocity, Delivery Head, Number of Coils, Discharge, Number of Paddles, Paddle-Wheel rotational speed Overall HCP efficiencies of up to 22 percent were obtained. The efficiency would drop as the stream velocity increased. Stream velocity has been identified as the most influential factor with regards to the variables analysed by this study. The HCP is ideal for rural application. The simplicity of the design ensures reliability as well as an effective water supply solution. The HCP is ideal for slow flowing rivers and can deliver up to 1190ℓ/h to a delivery head of 5m with a stream velocity of 1.2m/s. This is sufficient to supply a small rural community with running water.
  • Full Text:
  • Date Issued: 2013

Analysis of ICT governance initiatives as a mechanism to enhance corporate governance, with particular reference to Nelson Mandela Bay Municipality

  • Authors: Tolom, Sindiswa
  • Date: 2013
  • Subjects: Corporate governance -- South Africa -- Nelson Mandela Bay Municipality , Information technology -- Management
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:8904 , http://hdl.handle.net/10948/d1020999
  • Description: Developing countries such as South Africa have a tremendous potential for rapid and sustainable economic and social development by leveraging the benefits and advantages of Information and Communication Technology (ICT) and applying it appropriately within the local government sector. As such, the Local Government Turnaround Strategy’s (LGTAS) vision states that: Each municipality must have the necessary ICT infrastructure and connectivity; and that ICT systems must be put in place across all municipalities to accelerate service delivery, and improve efficiency and accountability. However, technology on its own cannot achieve much; it must be supported by capable people and tested processes to provide services in which the public can have confidence. Disparities, both from within the municipal sector as well as in the larger South African ICT landscape, have influenced the manner in which municipalities make use of ICT. Nevertheless, it has been observed that despite the use of ICT, there has been a lack of utilising ICT governance to enhance corporate governance in the public sector, particularly in municipalities. In this study, an analysis was made of ICT governance initiatives, as a mechanism to enhance corporate governance, with particular reference to the Nelson Mandela Bay Municipality (NMBM) in the Eastern Cape. The research itself has identified risk levels that exist as a result of the lack of ICT governance and risk management. The respondents were given an opportunity to agree or disagree with statements regarding the state of ICT provision and support, corporate governance and other elements within the institution. The researcher has formulated recommendations to solve identified problem based in the research results in ICT governance and corporate governance. While governance developments have primarily been driven by the need for transparency regarding enterprise risks and the protection of shareholder value, the pervasive use of technology has created a critical dependency on ICT that calls for a specific focus on ICT governance. ICT governance is part of corporate governance,which is the responsibility of the organisation’s top executive, to ensure that its information technology supports the goals and objectives of the organisation, through a variety of structural mechanisms, processes and mechanisms for communication. Fundamentally, ICT governance is concerned with whether ICT is delivering value and the management of ICT risks, driven by a strategic alignment between business and ICT, resources management and performance management. The corporate governance of ICT involves evaluating and directing the plans for the use of ICT to support the Institution and monitoring these. It includes the strategy and policies for using ICT within the institution. The executive authority and executive management are accountable and responsible for ensuring that the governance of ICT is implemented in the institution in line with this framework.
  • Full Text:
  • Date Issued: 2013

Analysis of official development assistance (ODA) in the Eastern Cape Province

  • Authors: Sotondoshe, Tolbert Hlanganisile
  • Date: 2013
  • Subjects: Economic assistance -- South Africa -- Eastern Cape , Economic development -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:9202 , http://hdl.handle.net/10948/d1020422
  • Description: In this study Official Development Assistance (ODA) is defined as resource flows from international community in the form of grants, technical assistance, support and financial co-operation. Government is held partially responsible or accountable for the management of these resources but not accountable for utilization of direct support to NGOs and private sector. According to the National Treasury’s Official Development Assistance (ODA) 2010 Review Report, the Eastern Cape is the second largest recipient of ODA in relation to other provinces. The province of KwaZulu Natal, ranked number one, and the province of Limpopo was recorded as the third largest recipient of ODA. As such it is recorded that European Union is the greatest funder in the provincial government focusing in the areas of Health, Urban renewal and Local Economic Development source (National Treasury ODA 2010 Review Report). To date, no analysis has been done on ODA in the Eastern Cape. This study seeks to analyse Official Development Assistance in Eastern Cape with a view to identifying constraints and gaps that may be contributing towards the ineffectiveness of ODA in the Eastern Cape.
  • Full Text:
  • Date Issued: 2013

Analysis of protein thermostability enhancing factors in industrially important thermus bacteria species

  • Authors: Kumwenda, Benjamin , Litthauer, Derek , Tastan Bishop, Özlem , Reva, Oleg
  • Date: 2013
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/123085 , vital:35404 , https://doi.10.4137/EBO.S12539
  • Description: Elucidation of evolutionary factors that enhance protein thermostability is a critical problem and was the focus of this work on Thermus species. Pairs of orthologous sequences of T. scotoductus SA-01 and T. thermophilus HB27, with the largest negative minimum folding energy (MFE) as predicted by the UNAFold algorithm, were statistically analyzed. Favored substitutions of amino acids residues and their properties were determined. Substitutions were analyzed in modeled protein structures to determine their locations and contribution to energy differences using PyMOL and FoldX programs respectively. Dominant trends in amino acid substitutions consistent with differences in thermostability between orthologous sequences were observed. T. thermophilus thermophilic proteins showed an increase in non-polar, tiny, and charged amino acids. An abundance of alanine substituted by serine and threonine, as well as arginine substituted by glutamine and lysine was observed in T. thermophilus HB27. Structural comparison showed that stabilizing mutations occurred on surfaces and loops in protein structures.
  • Full Text:
  • Date Issued: 2013

Analysis of restricted earth fault relay application within a shunt capacitor bank design impacting on protection stability

  • Authors: Minkley, Warick
  • Date: 2013
  • Subjects: Electric power systems -- Protection , Electric power transmission -- Equipment and supplies -- Protection
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:9604 , http://hdl.handle.net/10948/d1021106
  • Description: This research is aimed at analyzing the performance of the restricted earth fault relay used on a 400kV capacitor bank scheme used on the Eskom Transmission network. After the commissioning of two Capacitor Banks using the above mentioned scheme design the plant was energized. As a result of the energization the Shunt Capacitor Bank (SCB) then experienced spurious trips. The cause of the trips was found to be the operation of the restricted earth fault relay. In this research project, restricted earth fault protection on SCBs in the Eskom Transmission environment will be the area of interest. The proposed research will analyze the current SCB protection scheme in service specifically looking at the restricted earth fault circuit design and relay performance. An equivalent model of the SCB from primary plant perspective based on theory will be derived. Recording and analyzing of Comtrade transient waveforms respectively, when the bank is nergized, will be done in order to provide a reference base to work from. Manual alculations of various parameters from the derived model including transient inrush currents and fault currents will be performed to access applicable scheme parameters. Further calculations will include the voltage setting for the restricted earth fault relay. As a result of the analysis a recommendation will be made on a viable solution or a revised design will be put forward, based on the results, to improve the scheme’s performance. The protection scheme is used on the two 400kV 100MVAR capacitor banks 11 and 12 at Hydra Substation.
  • Full Text:
  • Date Issued: 2013

Analysis of temporal and spatial variations in water storage by means of gravimetric and hydrologic methods in the region around the South African gravimetric observation station

  • Authors: Mahed, Gaathier
  • Date: 2013
  • Subjects: Ground water -- South Africa , Geology -- South Africa , Hydrogeology -- South Africa , Water-supply -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/6714 , vital:21137
  • Description: This work examines the use of gravity data and its application to subsurface water reservoirs in the immediate vicinity of the South African Geodynamic Observatory, Sutherland (SAGOS), situated in a semi-arid region of the Karoo region of South Africa, and underlain by the Karoo sedimentary rocks intruded by dolerite dykes and sills. SAGOS houses the only supergravity metre (SG) in Africa, and this thesis sets out to test its use in monitoring groundwater dynamics using hydrological and gravity data. The main aim of this work is the application of the SG data, in conjunction with hydrological data, to better understand episodic recharge of subsurface reservoirs. The importance of water as a resource, globally and specifically the Karoo, is reviewed in conjunction with supply and demand of water. This is to contextualise the socio-economic, technical as well as policy issues related to water resource management. Applicable technologies for water resource management and efficient water use are highlighted and the application of gravity to hydrology is introduced, including satellite as well as ground based tools. In addition, arid zone hydrology as well as recharge and its mechanisms are analysed in order to better understand these processes when examined from gravity measurements. Issues related to understanding flow within the vadose zone as well as in secondary aquifers are examined, and gravity residuals and subsurface hydrology are highlighted. Thereafter, a conceptual groundwater flow modelof the study area is developed using multiple tools. First, the geology around SAGOS was mapped using SPOT 5 imagery and then ground truthed. Second, stable isotopes and water chemistry analysis was undertaken on water samples from selected boreholes. The results allude to preferential flow acting as the main mechanism for groundwater recharge. Follow-up pump-tests illustrate that fracture connectivity is greatest at close proximity to the dyke. Soil mapping, using aerial photography was also undertaken. Duplex soils, enriched with clay at depth, dominate the study area. Using in-situ infiltration tests, it is shown that the alluvium, which lines the river beds, has a higher hydraulic conductivity than the other soils, confirming that these streams act as preferential conduits for subsurface recharge. Precipitation events were correlated against gravity residuals at 4 wells, over different time periods. The results are examined using time series analyses. Gravity residuals from well SA BK07, over a period of 24 hours after the rainfall event, delineate instances of negative correlations, as well as strong positive correlations (of up to 0.9). On the whole however, correlations between gravity and groundwater at SA BK07 are variable and weak, and in conjunction with water level measurements and water chemistry, the data suggest that this well is located in a dynamic conduit (throughflow) and not in a permanent groundwater reservoir. By contrast, other wells show strong positive correlations between gravity residuals and water levels following episodic recharge events for a later time series. Correlations between the water levels and gravity residuals in wells SA BK04, SA BK05 and SA BK 01 are in excess of 0.7 for specific rainfall events. In summary, the results suggests that gravity is an excellent tool for measuring episodic groundwater recharge within the immediate vicinity of the SAGOS. This implies that gravity can aid in monitoring groundwater losses/gains in arid and semi-arid areas. Recommendations for future work are highlighted at the end; these include the possible use of hydrological modelling of reservoirs at various scales and then comparing these results to the SG as well as GOCE and GRACE satellites data, and then improving numerical modelling of the groundwater dynamics for sites like Sutherland and the surrounding arid Karoo region, where sparse water shortages, and potential pollution related to fracking for shale-gas, are likely to compete with established water needs for farming and human consumption. It is also suggested that the gravity modelling be examined to better understand site specific scenarios and thus aid in improving the processing of the gravity signal.
  • Full Text:
  • Date Issued: 2013

Analysis of the implementation of corporate level strategy in a South Afircan furniture retailer

  • Authors: Nkatsha, Thembinkosi Sydney
  • Date: 2013
  • Subjects: Reengineering (Management) , Consolidation and merger of corporations -- South Africa -- Case studies , Organizational change -- Management
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:856 , http://hdl.handle.net/10962/d1018272
  • Description: [Integrative Summary] This study is situated in the complex field of change management, and strategy execution. The study focuses on the corporate level restructuring of Ellerine Holdings Limited (EHL), subsequent to its acquisition by the micro lending financial institution African Bank Investments Limited (ABIL). The interest of the researcher was aroused by the uniqueness of the relationship. This was the first of its kind in a South African context, where a banker owned a furniture retailer. The restructuring was undertaken shortly after the acquisition. This research paper adopted a case study approach, in describing the restructuring initiative that took place in EHL, focusing on the period between January 2008 and the end of 2010/ 11 financial year on the 30th of September 2011. The case captures the significant phases of the restructuring including a background of (1) the protagonist, Toni Fourie (Chief Executive Officer), (2) EHL as the researched company, (3) the industry it operates in, and (4) the case content. Brief teaching notes have been provided to explain the teaching value of the case and to assist with its delivery in the classroom. Attention is drawn to a presentation by the protagonist in November 2011, named 'A CEO Insight' where he gave an overview and insights of the road travelled in restructuring Ellerine Holdings Limited, and more importantly highlights the following about the purpose and nature of the restructuring of the organisation. • A plan to change the way the industry works. • The creation of a profitable, stand-alone retail business through: o The sale of two companies, the closure of two companies and consolidating from thirteen to six brands. o Separating financial services from retail. o Moving the financial services component to African Bank, also a subsidiary of ABIL. o Redesigning the credit model. o Completion of twelve system changes. • Over R600million reduction in cost • A place where people want to work. The restructuring outlined above represents a major shake-up in many aspects of the corporation. The main challenge for Toni Fourie and his team was: how best could they restructure EHL to extract synergies between their two subsidiaries Ellerine Holdings Limited & African Bank to increase shareholders ' value at Group level. The case seeks to describe this in detail. The overarching strategy underpinning the restructuring of the researched corporation is premised on the price volume elasticity equation, by reducing the cost of credit, thereby driving pricing down within the brands, and facilitating more people having access to affordable credit. The case study of the restructuring is presented in Section 1. A review of relevant literature on strategy implementation is presented in Section 2, focusing on restructuring. Successful implementation of strategies only takes place with structures that are developed by organisations to support the achievement of their strategic objectives. Organisational architecture and design have a critical role to play in the execution of organisational strategies. Nadler and Tushman (1978) emphasise the importance of congruence in the organisational design, for the organization to not only deliver superior results but to sustain them over a period of time. Research by Okumus (2005) seems to tell us that the lack of credible framework to implement strategy, has contributed the high failure rate of strategy initiatives. Although this is a strategy implementation case, it also touches on aspects of leadership - mainly the architectural role - and the role, or influence of strategic leadership, in restructuring the corporation. The results of this research paper were achieved by following a specific research methodology. The aim of the research was to analyse the restructuring of the researched company at corporate level, having the following objectives in mind; • Understanding the strategy. • Analysing the design decisions in the light of the strategy chosen by the top management of Ellerine Holdings Limited. • Analysing what monitoring and control measures had been designed to facilitate the corporate restructuring. Data was collected through documentation of the corporation that was made available to the researcher on request, as well as those that are in the public domain, and an interview with the CEO of the researched company. The interview was conducted after analysing the documentation (Hakim, 2000). The Methodology is detailed in Section 3. The researcher hopes that the case study will contribute to learning about business leadership and strategic management. The case should develop an understanding of the complexities related to strategy execution at corporate level, particularly the restructuring aspect of it.
  • Full Text:
  • Date Issued: 2013

Analysis of the influence of peer education programmes on learner behaviour, the case of Bulelani high school, Queenstown

  • Authors: Bedula, Nomanani Doris
  • Date: 2013
  • Language: English
  • Type: Thesis , Masters , MPA
  • Identifier: http://hdl.handle.net/10353/1165 , vital:26532
  • Description: This study focuses on the influence of peer education programmes on learner behaviour. Peer education is a critical approach for behaviour-change. The presentation had two objectives. The first objective was to determine the nature and extent of peer education programmes policy implementation in the school under study. The second objective was to determine the impact of the policy on learner behaviour. A questionnaire which was administered to all trained peer educators at Bulelani High School indicated that all respondents agreed that peer education was educationally relevant and offered accurate information. Furthermore, results indicated that older learners strongly agreed that peer education programmes have an impact on behavioural changes than younger learners who merely agreed on that. The results also showed that the duration of involvement in peer education programmes influences the opinion on the impact of peer education on behavioural changes. Looking at the respondents ’gender, the researcher could not find any evidence that the impact of peer education on behavioural change depends on the gender of the respondent and therefore concludes that opinions are independent of gender. The study shows that in schools where peer education programmes are well implemented and monitored, they do impact on learner-behaviour in a positive way.
  • Full Text:
  • Date Issued: 2013

Anchovy and Sardine in Algoa Bay and their relationship with response variables in two threatened avian predators

  • Authors: Potter, Cara-Paige
  • Date: 2013
  • Subjects: Fishes -- Predators of -- South Africa -- Algoa Bay , Anchovies -- South Africa , Sardines -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10730 , http://hdl.handle.net/10948/d1021130
  • Description: Huge populations of sardine and anchovy exist in the four major upwelling systems around the world. These fish are both important ecologically and economically. Pelagic fish dominate the mid trophic level and can exert both a top-down control of zooplankton and a bottom-up control on predatory fish and marine top predators. They also make up a substantial contribution of the world catches in seas around the world where they co-exist in upwelling areas. The fluctuations of sardine and anchovy are largely influenced by recruitment from the larval stage and by the physical environmental forces that determine the planktonic compositions upon which they feed. In southern Africa, the biology and behaviour of two threatened seabird species, African penguins (Spheniscus demersus) and Cape gannets (Morus capensis), are directly influenced by the availability of sardine (Sardinops sagax) and anchovy (Engraulis encrasicolus). This study aimed to provide further insight into the fluctuations of sardine and anchovy in relation to the variability of environmental factors such as wind, sea surface temperature, rainfall and plankton abundance, focusing specifically on Algoa Bay in the Eastern Cape, South Africa. Algoa Bay is particularly important as it is home to the world’s largest African penguin colony and the world’s largest gannetry. Therefore, to further investigate the populations of these two seabird species, the fluctuations of their food source were studied.
  • Full Text:
  • Date Issued: 2013

Anniversary Bulletin 1943-2013: 70 Years of Struggle... and the Struggle Continues

Antifugal evaluation and phytochemical analysis of selected medicinal plants used in the treatment of fungal diseases associated with HIV infection in the Eastern Cape Province, South Africa

  • Authors: Mbeng, Wilfred Otang
  • Date: 2013
  • Subjects: Medicinal plants -- ethnobotanical survey , Opportunistic fungal infections , HIV/AIDS -- Cytotoxicity , Eastern Cape -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD (Botany)
  • Identifier: vital:11307 , http://hdl.handle.net/10353/d1006834 , Medicinal plants -- ethnobotanical survey , Opportunistic fungal infections , HIV/AIDS -- Cytotoxicity , Eastern Cape -- South Africa
  • Description: Background. As a result of the AIDS pandemic, many people areimmuno compromised andopportunistic fungal infections (OFIs) such as candidiasis are common. Despite the widespread use of medicinal plants in South Africa, there is a dearth of knowledge regarding the use of such plants in the management of these infections. This study evaluates three South African medicinal plants (Arctotis arctotoides, Pittosporum viridiflorum, and Gasteria bicolor) traditionally used in the treatment of OFIs in HIV/AIDS patients, in the Eastern Cape Province, South Africa. Materials and methods. A six-stage process of documentation, evaluation and analysis of results was conducted: (1) Selection of medicinal plants most frequently used in the treatment of OFIs through ethnomedical studies and the survey of specialised literature; (2) Collection and preparation of the extract of each plant; (3) Antifungal evaluation of the crude plant extracts. (4) Phytochemical and antioxidant evaluation of the active crude plant extracts; (5) Cytotoxicity evaluation of the bioactive extracts using the Chang liver cell line, and (6) Statistical analysis of the results. Ethnobotanical information was obtained through interviews with traditional healers and AIDS patients with the aid of semi-structured questionnaires, direct observations and by reviewing studies reported in the literature. Following the approval from the University of Fort Hare‘s Ethics Committee, 101 HIV/AIDS patients were recruited through convenience sampling into an anonymous cross-sectional questionnaire study. The agar diffusion and micro-dilution methods were used to determine the antifungal activities of the hexane, acetone and aqueous extracts of A. arctotoides, G. bicolor and P. viridiflorum against 10 opportunistic fungi.
  • Full Text:
  • Date Issued: 2013

Antimicrobial activities of three medicinal plants against selected diarrheagenic pathogens

  • Authors: Nkosi, Themba Johan
  • Date: 2013
  • Subjects: Anti-infective agents , Drug resistance in microorganisms , Materia medica, Vegetable
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:10126 , http://hdl.handle.net/10948/d1020759
  • Description: Diarrhea is a global concern that the United Nations Children’s Fund (UNICEF) and the World Health Organization (WHO), have confirmed to be the second major cause of death in children under the age of five. Major bacterial pathogens that cause diarrhea include Escherichia coli, Salmonella species, Shigella species and Staphylococcus aureus. Antibiotic therapy is recommended depending on the severity and presentation of the disease; however, the appearance of antibiotic-resistant bacteria is an emerging global threat to the ability to treat these bacterial infections. This situation could be overcome by the discovery of new natural antibiotics. Plants have been a source of medicine for centuries and have been used to treat diseases including diarrhea. This makes plants a natural potential target to study for their antibiotic properties. The objective of this study was to determine the antibiotic properties of medicinal plants against known pathogens that cause bacterial diarrhea. Three medicinal plants, Cassia abbreviata, Kigelia africana, and Geranium incanum were investigated for their antimicrobial properties against these strains of microorganisms: American Type Culture Collection (ATTC) and Clinical Strains (CS). The plant materials were ground into powder, which was then dissolved in methanol, acetone and distilled water to extract the active compounds. The plant extracts were then used to (i) determine their antibiotic activity, (ii) determine the minimum inhibitory concentration (MICs), (iii) analyze the thin layer chromatography (TLC) fingerprints, and (iv) analyze the autobiography assay. The results obtained in this study met the aim and objectives of this study. The antimicrobial activities of the selected plants were obtained as discussed in Chapter 2 and 3. These results indicated that the traditional plants could be used as antimicrobials. In the screening assays, the test microorganisms were inhibited by the plant extracts, when they were subjected to plant extracts. This was performed on Mueller Hinton agar as sensitivity testing, which revealed clear zones of inhibition. The MIC values for each plant extract were established which ranged from 0.101 to 13.3 mg/dl. The TLC analysis revealed the spots which contained the active compounds which inhibited the bacterial growth. A bioautography assay was performed on the TLC plates, which exposed the exact spots containing the active compound inhibiting the bacteria. These results are clearly consistent with what former scientists have observed. Detailed explanations on the results are in Chapter 3 and 4 of this paper. It is important to note that all the procedures performed in this study were in vitro assays. Some effective in vitro assay activity may not always result in the same effective in vivo activity, because some active compounds may be metabolized and degraded into inactive metabolites. For this reason, the in vitro results obtained in this study, may not reflect the true effectiveness of the compounds in in vivo trials. It is therefore advised that future scientists should take a step further in analyzing the plant extracts through in vivo assays. Further testing and study on these plants at an advanced molecular level will be beneficial in the medical fields in the search for new antibiotics to treat infectious diseases. Purification and further analysis of their products can be helpful in the production of pure natural medicines. This will discover the active ingredients and compounds responsible for inhibition of the microorganisms. This will make the compounds potential candidates for a scientific validation and analysis for future scientists to bring a new dawn in the fight against infectious diseases.
  • Full Text:
  • Date Issued: 2013

Application of assisted reproduction technologies on the indigenous Nguni cows and heifers

  • Authors: Maqhashu, Ayanda
  • Date: 2013
  • Language: English
  • Type: Thesis , Masters , MSc Agric (Animal Science)
  • Identifier: vital:11828 , http://hdl.handle.net/10353/d1016096
  • Description: The aims of the study were to compare superovulatory (SO) response rate and embryo quality recovered; consequently, correlate sperm motility with fertilization rate on superovulated stud Nguni cows and heifers. Furthermore, compare oestrous synchronization response and pregnancy rate of three breed type cows (Brahman, Bonsmara and Nguni) of different body condition scores following timed artificial insemination in KwaZulu-Natal (KZN) and Limpopo provinces. Nguni stud cows (n= 15) and heifers (n= 10) aged 4-6 and 2-3 years were used as embryo donors. Superovulation of donors involved insertion of a controlled internal drug release device (CIDR) and two injections of FSH daily 12 hours apart for 4 days on a decreasing dosage. Fresh Nguni semen was collected from proven Nguni stud bulls and assessed by computer aided sperm analysis (CASA) before artificial insemination (AI). The doses of AI were prepared and conducted twice, 12 hours apart on synchronized and superovulated Nguni cows or heifers. Embryos were flushed 7 days after AI using a non-surgical technique. Embryos were immediately evaluated under stereo microscope and classified according IETS standard codes (C1, C1- and C2). All transferrable embryos were vitrified. Two pilot study sites were chosen in Eastern Cape – Great kei; (n= 5) and Limpopo - Vuvha; (n=5) provinces for Embryo transfer. Each recipient cow was implanted with one frozen-thawed embryo. For oestrous synchronization, cows (Braman, Bonsmara and Nguni type) were selected in different villages, regardless of parity, age, breed and body weight following pregnancy diagnosis. Cows were grouped according to breed type and body condition scores (BCS) on a scale of 1-5. Group 1 had BCS of ≤ 2.5 in KwaZulu-Natal (n=81) and Limpopo n=71), Group 2 had BCS of ≥ 3 in KwaZulu-Natal (n=79) and Limpopo (n=100) cows. Cows were synchronized by inserting the controlled intravaginal drug release (CIDR) and removed on Day 8, followed by administration of prostaglandin. The white heat mount detectors (HMD) were placed on the individual cow’s tail head as an indicator for oestrous response if colour changed to red and inseminated twice at 12 hours interval. Pregnancy diagnosis was performed by an ultra sound scanner and rectal palpation 90 days after TAI in embryos and semen recipient cows. There was no significant difference on the superovulatory response rate between Nguni cows (40%) and heifers (40%). There was a significant difference on the ovary reaction (number of corpus luteum) of cows (11.33±1.41) and heifers (4.00±0.57). There were no significant differences observed on the embryo quality between Nguni cows (2.5±1.00 and 1.25±0.59) and heifers (0.83±0.41 and 1.00±0.36) for excellent (C1) and good (C1-). However, cows had more numbers of unfertilized ova (5.5±1.05 and 1.75±0.47) and degenerate embryos (3.66±1.00 and 1.25±0.39) than heifers. Village cows responded to oestrous synchronization successfully in KZN (100%) and Limpopo (99%) regardless of body conditions and breed type. The lowest pregnancy rate was recorded in Brahman and Bonsmara type cows with BCS of ≤ 2.5 regardless of Province. Interestingly, Nguni type cows with same body condition of ≤ 2.5 had higher average pregnancy rate of 59.5% in Limpopo and 53.5% in KZN. However, cows with BCS of ≥3 had better pregnancy rate regardless of cow breed type, and province. In conclusion, only 40% of both Nguni cows and heifers responded to superovulation. However, Nguni cows had better ovaries reaction compared to heifers. The quality of embryos recovered was similar for both Nguni cows and heifers. Moreover, there was a positive correlation between total sperm motility and fertilization rate bull 1 (93.7%) inseminated the cows (67.5%) and bull 2 (83.5%) inseminated the heifers (53.5%). Higher pregnancy rate (60%) was recorded in Limpopo compared to Eastern Cape (0%). Interestingly, more than 99% of village cows responded to synchronization and inseminated with frozen-thawed semen successfully. Village Nguni type cows were not affected by body condition scoring as they had higher and similar pregnancy rate as those that had body condition of ≥ 3. It is suggested that it is not advisable to breed synchronized Brahman and Bonsmara type cows with the body condition of ≤ 2.5 except in Nguni cow type as more than 57% average pregnancy rate was achieved.
  • Full Text:
  • Date Issued: 2013

Application of bidentate N,N'-donor extractants in the hydrometallurgical separation of base metals from an acidic sulfate medium

  • Authors: Okewole, Adeleye Ishola
  • Date: 2013
  • Subjects: Hydrometallurgy Sulfates Nanofibers Electrospinning Sorbents Extraction (Chemistry) Solvent extraction Stereochemistry
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4281 , http://hdl.handle.net/10962/d1002610
  • Description: Bidentate imidazole-based extractants, 1-octylimidazole-2-aldoxime (OIMOX) and 1-octyl-2-(2′-pyridyl)imidazole (OPIM), along with dinonylnaphthalene sulfonic acid (DNNSA) as a synergist, were investigated as potential selective extractants for Cu²⁺and Ni²⁺ respectively from base metals in a solvent extraction system. The study was extended to evaluate the sorption and separation of Ni²⁺ from other base metals in a solid-solution system using microspherical Merrifield resins and nanofibers functionalized with 2,2′-pyridylimidazole. Copper was effectively separated with OIMOX and DNNSA as extractants from nickel with ΔpH½ ≈1.05 and the extraction order of Cu²⁺ > Ni²⁺ > Zn²⁺ > Cd²⁺> Co²⁺ was achieved as a function of pH. At pH 1.65 the extracted copper, from a synthetic mixture of the base metals reached 90.13(±0.90)%, and through a two-step extraction process 98.22(±0.29)% copper was recovered with negligible nickel and cobalt impurities. Stripping of the copper from the loaded organic phase using TraceSelect sulphuric acid at pH 0.35 yielded 96.60(±0.44)% of the loaded quantity after the second stage of stripping. The separation of Ni²⁺ from the borderline and hard acids; Co²⁺, Cu²⁺, Zn²⁺, Fe2²⁺, Fe²⁺, Mn²⁺, Mg2²⁺ and Ca²⁺ at a pH range of 0.5-3.5 with OPIM and DNNSA was acvieved to the tune of a ΔpH½≈ 1.6 with respect to cobalt from a sulfate and sulfate/chloride media. A three-stage counter-current extraction of Ni²⁺, at the optimized pH of 1.89, from a synthetic mixture of Ni²⁺, Co²⁺ and Cu²⁺, yielded 99.01(±1.79)%. The total co-extracted Cu²⁺ was 48.72(±0.24)% of the original quantity in the mixture, and it was 19.85(±0.28%) for Co²⁺. The co-extracted Cu²⁺ was scrubbed off from the loaded organic phase at pH≈8.5 by using an ammonium buffer, while co-extracted Co²⁺ was selectively and quantitatively stripped with H₂SO₄ at pH 1.64. The total recovery of Ni²⁺ by stripping at pH 0.32 was 94.05(±1.70)%. In the solid-liquid system, Ni²⁺ was separated from Co²⁺, Cu²⁺, and Fe²⁺ with the microspherical resins funtionalised with 2,2′-pyridylimidazole by a separation factor (β) in the range 22-45. Electrospun nanofibers as sorbents yielded high sorption capacity in the range of 0.97 - 1.45 mmol.g⁻¹ for the same metals ions. Thus, 1-octylimidazole-2-aldoxime (OIMOX), and1-octyl-2-(2′-pyridyl)imidazole (OPIM) can be effectively utilized alongside DNNSA as a co-extractant in the separation of Cu²⁺ and Ni²⁺ respectively from base metals in acidic sulfate medium in a solvent extraction process, and the latter as a selective ligand in the solid-liquid separation of Ni²⁺ from Co²⁺, Cu²⁺, and Fe²⁺.
  • Full Text:
  • Date Issued: 2013

Application of lie group analysis to mathematical models in epidemiology

  • Authors: Otieno, Andrew Alex Omondi
  • Date: 2013
  • Subjects: Epidemiology -- Mathematical models
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:18486 , http://hdl.handle.net/11260/100
  • Description: Lie group analysis is arguably the most systematic vehicle for finding exact solutions of differential equations. Using this approach one has at one's disposal a variety of algorithms that make the solution process of many differential equations algorithmic. Vital properties of a given differential equation can often be inferred from the symmetries admitted by the equation. However, Lie group analysis has not enjoyed wide-spread application to systems of first-order ordinary differential equations. This is because such systems typically admit an infinite number of Lie point symmetries, and there is no systematic way to find even a single nontrivial one-dimensional Lie symmetry algebra. In the few applications available, the approach has been to circumvent the problem by transforming a given system of first-order ordinary differential equations into one in which at least one of the equations is of order two or greater. It is therefore fair to say that the full power of Lie group analysis has not been sufficiently harnessed in the solution of systems of first-order ordinary differential equations. In this dissertation we review some applications of Lie group analysis to systems of first order ordinary differential equations. We shed light on the integration procedure for first-order systems of ordinary differential equations admitting a solvable Lie algebra. We do this via instructive examples drawn from mathematical epidemiology models. In particular we revisit the work of Nucci and Torrisi [54] and improve the exposition of the Lie-symmetry-inspired solution of a mathematical model which describes a HIV transmission. To aid implementation of the integration strategy for systems of ordinary differential equations, we have developed ad-hoc routines for finding particular types of admitted symmetries and checking if a given symmetry is indeed admitted by a system of ordinary differential equations.
  • Full Text:
  • Date Issued: 2013

Applying a student curriculum discourse in higher education teaching and learning

  • Authors: Mndzebele, Samuel , McKenna, Sioux
  • Date: 2013
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/187417 , vital:44633 , xlink:href="https://doi.org/10.1080/18146627.2013.786210"
  • Description: Indications of poor quality in students’ written work necessitated the need for deeper investigations aimed at designing and applying appropriate teaching/learning and assessment innovations in the course curriculum. The project-exercise engaged a conceptual-explorative approach through: reviews/investigations; educational diagnosis; design/application of innovations and evaluation processes. In addition to other challenges, diagnosed problems included: students’ ignorance on key curriculum components; imbalance in teaching/learning and assessment tasks engaging all 3-learning domains; less intensiveness of the e-learning mode; and superficial formative feedback. Included a “Student-Curriculum-Discourse” self-tutorial guide, and tasks alignment of the teaching/learning and assessment. Learners’ performance can be improved through a curriculum-discourse self-tutorial exercise, complemented with: intellectual, social, experiential, and emotional structures. Both educators and learners share specific responsibilities in the teaching/learning environment. There is need to expand/probe the theoretical dimension within which the on-line distance education occurs.
  • Full Text:
  • Date Issued: 2013

Aspects of constructive dismissal

  • Authors: Diedericks, Shaun Sylvester
  • Date: 2013
  • Subjects: Labor courts , Employees -- Dismissal of
  • Language: English
  • Type: Thesis , Masters , LLM
  • Identifier: vital:10269 , http://hdl.handle.net/10948/d1011641 , Labor courts , Employees -- Dismissal of
  • Description: Before the introduction of the concept of constructive dismissal in the LRA, the old industrial courts relied on the strides made in this field by the English and American courts. Constructive dismissal is the fourth type of dismissal and it is instituted by the employee through his/her resignation, unlike the other three types of dismissals which is instituted by the employer. Section 186(e) of the LRA defines constructive dismissal as the termination a contract of employment with or without notice by the employee because the employer made continued employment intolerable for the employee. With a fundamental breach in the contract of employment employees have a choice to either base their claims on constructive dismissal in the LRA or repudiation of the contract in common law, depending on the circumstances. Landmark judgments like Jooste v Transnet and Pretoria Society for the Care of the Retarded v Loots set the tone for constructive dismissal law in South Africa. It introduced the concept of intolerability as well as looking at the employer‟s conduct as a whole and judging it reasonable. The test for constructive dismissal throughout the evolution of case law in South Africa has not changed. Constructive Dismissal under the common law is also discussed in depth by looking at the landmark judgment of Murray v Minister of Defence. Sexual Harassment in the workplace is of a growing concern. If continued sexual harassment makes continued employment intolerable, the employee subjected to the harassment has the option of resigning and approaching the CCMA or bargaining councils, and claim that they have been constructively dismissed. Cases such as Payten v Premier Chemicals and Gerber v Algorax (Pty) Ltd really shows us how difficult it is to proof constructive dismissal as a result of sexual harassment because in most instances there won‟t be witnesses and it would be a case of he said, she said. These cases also show us that it can be proven based on a balance of probabilities. Grogan states that in dismissal proceedings, the onus is on the employees to prove that they were in fact dismissed and on the employer to show that the dismissal was fair. Section 192 of the LRA places another burden on the employee that requires him to not only prove the existence of a dismissal, but also that the conduct of the employer was intolerable. Unlike normal dismissal cases, commissioners generally award compensation as a remedy for constructive dismissal. A claim by an employee for reinstatement would be contradicting a claim that the employment relationship became intolerable and an award for reinstatement would be very inappropriate in a case of constructive dismissal. In short, unlike a normal dismissal, a constructive dismissal is a termination of the employment contract by the employee rather than the employer‟s own immediate act.
  • Full Text:
  • Date Issued: 2013

Aspects of isiXhosa poetry with special reference to poems produced about women

  • Authors: Jadezweni, Mhlobo Wabantwana
  • Date: 2013
  • Subjects: Laudatory poetry, Xhosa African poetry (English) -- History and criticism Women in literature Women and literature -- South Africa African poetry -- Women authors
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3616 , http://hdl.handle.net/10962/d1006364
  • Description: This study investigates the use of modern and izibongo (praise poetry) techniques in representing women in selected isiXhosa poems. The main interest of the study is to determine whether the same techniques to depict men are used when writing about women. It is also the interest of the study to ascertain how gender issues are dealt with in the selected poems. Seminal studies on izibongo by eminent scholars in this field show a serious lack of critique and little recognition of women in African languages’ poetry in general and in isiXhosa in particular. Pioneering studies in Nguni poetry about women have thus recommended that serious studies on poetry about women be undertaken. The analyses of selected poems by established isiXhosa poets show that modern poetry conventions are significantly used together with izibongo techniques. These techniques are used without any gender differentiation, which is another point of interest of this study. There are however instances where images specific to women are used. Such use has however not been found to be demeaning of women in any way. Poems where modern poetry forms and conventions are used tend to deal with subjects who have international or an urban area background. Even though the modern poetry conventions are used with izibongo techniques the presence of the modern literary conventions is prominent. This is the case particularly with poems about women in politics. That some female poet seems to accept some cultural practices that are viewed to be undermining the status of women does not take away the voice of protest against this oppression by some of the selected poets. These two voices, one of acceptance and the other one of protest are used as a basis for a debate around a need for a literary theory that addresses the question of African culture with special reference to isiXhosa poetry about women. The success of the selected poets with both modern and izibongo techniques is a good sign for the development of isiXhosa poetry in general and isiXhosa poetry about women. It is strongly recommended that continued research of a serious nature concerning poetry about, and produced by women, be undertaken.
  • Full Text:
  • Date Issued: 2013

Assemblage dynamics of larval fishes associated with various shallow water nursery habitats in Algoa Bay, South Africa

  • Authors: Pattrick, Paula
  • Date: 2013
  • Subjects: Spawning -- South Africa -- Algoa Bay , Fishes -- Larvae -- South Africa -- Algoa Bay
  • Language: English
  • Type: Thesis , Doctoral , DPhil
  • Identifier: vital:10727 , http://hdl.handle.net/10948/d1021042
  • Description: The success of the larval stage in fishes plays a critical role in structuring adult fish populations. It is well understood that juveniles of many marine fish species are closely associated with nearshore and coastal habitats that serve as nursery areas while adult assemblages are more widely distributed. The larval phase however, particularly pertaining to nursery habitat use, remains poorly understood in South Africa. A mixed-method, larval and juvenile fish study was conducted in the warm-temperate shallow coastal waters of Algoa Bay, South Africa. Two years (2010 – 2012) of seasonal sampling at 27 stations at various habitat types revealed distinct spatio-temporal patterns in larval fish composition and abundance. In total, 164 species from 50 families were collected in the nearshore (<30 m), over reef and sand, in the surf zone and large estuarine habitats in Algoa Bay. Engraulidae dominated the larval fish catch in the nearshore (38.4 percent) and over the selected reef and sand habitats (37.8 percent). Cynoglossidae (28.1 percent) and Sparidae (8.4 percent) were the second and third most abundant fish families in the nearshore. In subtidal reef and sand habitats, Gobiidae (23.4 percent) and Clupeidae (9.2 percent) were the second and third most abundant families respectively. Sparidae dominated (71.4 percent) surf zones followed by Soleidae (10.8 percent) and Mugilidae (5.3 percent), while in the mouth area of two permanently open estuaries in Algoa Bay, Gobiidae (35.9 percent) Sparidae (30.1 percent) and Mugilidae (12.4 percent) dominated. Several species from the Blenniidae, Gobiesocidae, Gobiidae, Scorpaenidae and Tripterygiidae fish families complete their pelagic larval phase in the reef habitats in Algoa Bay. These reef habitats therefore serve as important nursery areas for the larvae of benthic species. The sand and nearshore habitats serve as nursery areas for Clupeidae and Engraulidae. Highest densities of Carangidae, Sciaenidae and Sparidae larvae were observed at the subtidal reef habitats indicating that this area is important for accumulation of the early developmental stages of these fishes. The nearshore serves as an important accumulation habitat for species in the Haemulidae and Soleidae families whose juveniles are known to recruit into estuarine nursery areas. The nearshore therefore is a specific area of presettlement buildup of larvae prior to settlement of larvae or juveniles in estuarine nursery areas. Cynoglossidae larvae are also using the nearshore as an accumulation area prior to settlement and recruitment into adult populations occurring in shallow water habitats. In the surf zone, not only are estuary-dependent fish species utilizing this habitat as a nursery area, but marinespecies whose adults are either associated with rocky shores or surf zones are similarly using these areas as nursery habitats. In addition, estuary-dependent fish species which spawn in the marine environment are actively recruiting into estuarine nursery areas on both tides. Active recruitment against the outgoing ebb tide flow was a conclusive finding in this study. These larvae and juveniles are actively swimming against the ebb tide in the shallower, slower-flowing marginal areas where current flow is reduced. Strong environmental gradients on multiple temporal and spatial scales occur in Algoa Bay. Seasonal patterns were evident in larval densities, richness and diversity. Peaks in density, richness and diversity occurred during spring and summer (September to February) associated with increasing water temperatures and a high productivity providing a good food environment for larval fishes. Thereafter densities declined steadily as a result of natural mortality, settlement or adult spawning activity, until autumn when numbers dropped suddenly as the surviving larvae moved to settlement habitats. The relationship between larval fish and environmental variables provides information useful to determine distributions. Therefore the Bay is particularly suited for modelling larval fish distributions. Using generalized linear models, larval fish density in the nearshore of Algoa Bay responded to different ocean features to varying degrees. Larval fish density responded positively to both upwelling and when warm water plumes, originating from an Agulhas Current meander, entered Algoa Bay. On subtidal reefs, habitat complexity played an important role in determining larval fish composition and diversity. The less structurally complex, reefassociated sand habitats, yielded higher species richness and diversity than the high and low profile reef habitats. Therefore, it is likely that the importance of less structurally complex habitats has been overlooked relative to other habitats in terms of their function for larval fishes. In the surf zone, wave period and wave height, which can be related to exposure, were the most significant environmental factors influencing larval fish assemblages. Greatest species diversity was observed in the surf zone habitats heavily influenced by wave action in the windward sector of Algoa Bay. The identification of spawning areas and the mapping of distributions of early developmental stages of fishes are important in providing data pertaining to the protection of these habitats. This is particularly relevant as a new marine protected area MPA)is planned for the eastern sector of Algoa Bay. Results from retrogressive plots indicate that the spawning locations of several species of coastal and pelagic fishes are occurring outside of the Bay, with the bay therefore serving as an accumulation area. Furthermore, distribution modelling results demonstrate that the early developmental stages of fishes in the shallow coastal habitats of Algoa Bay exhibit high spatial variability in their distributions. Results presented in this thesis help fill the knowledge gaps critical to the understanding of larval fish nursery areas of several economically and ecologically important fish species in Algoa Bay.
  • Full Text:
  • Date Issued: 2013
  • Disclaimer
  • Privacy
  • Copyright
  • Contact