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Dynamics of macrophytes in the East Kleinemonde, a small temporarily open/closed South Afrcan Estuary

  • Authors: Riddin, Taryn
  • Date: 2011
  • Subjects: Estuaries -- South Africa -- East Kleinemonde
  • Language: English
  • Type: Thesis , Doctoral , DPhil
  • Identifier: vital:10605 , http://hdl.handle.net/10948/1529 , Estuaries -- South Africa -- East Kleinemonde
  • Description: The East Kleinemonde Estuary is one of 175 temporarily open/closed estuaries (TOCEs) that represent 70 percent of estuaries in South Africa. TOCEs are small (mostly less than 100 ha), shallow estuaries (average depth < 2 m) that respond quickly to freshwater inflow events. Their connection to the sea can be highly variable resulting in considerable changes in abiotic and biotic conditions. Mouth status depends on a balance between freshwater inflow and marine influence, which in turn affects ambient abiotic conditions. The objective of the study was to identify the abiotic variables which influence macrophyte growth and habitat availability. It was hypothesised that water level and salinity were the two main drivers of macrophyte change and macrophyte habitat would respond very rapidly, in less than a month, when habitat was available. Macrophyte habitats would also have high sediment seed reserves to ensure persistence under highly variable abiotic conditions. Macrophyte cover was monitored monthly in the East Kleinemonde Estuary along three permanent transects. The dominant habitats were submerged macrophytes, intertidal salt marsh, supratidal salt marsh, reeds and sedges. The following abiotic variables; water level, water column salinity, water temperature, Secchi depth, air temperature and rainfall were also measured between March 2006 and January 2010. Time-lag responses of the macrophytes to water level and salinity changes up to four months prior to the sampling session were also assessed. The analysis of a one year dataset highlighted only water level as a driver of change in macrophyte cover, whereas the five year dataset identified salinity as an additional important abiotic driver. This is because during September 2008 to January 2010 a series of large marine overwash events maintained high salinity (> 30 ppt) and high water level (> 1.6 m amsl) in the estuary. Water level increased by up to 0.33 m due to large volumetric changes and salinity was significantly higher in the 16 month closed euhaline phase after the breach (31 ± 0.9 ppt) compared to 21.9 ± 0.9 ppt in the closed polyhaline phase before the September 2008 breach. This increase in salinity significantly reduced the cover of the submerged macrophytes Ruppia cirrhosa and Chara vulgaris. They were replaced by macroalgae during this high salinity phase. The cover of supratidal salt marsh and reed habitats was also significantly reduced during the high water level phase, which in turn would lead to the potential for bank destabilisation and erosion. Based on the average elevation above sea level position of the macrophytes in the East Kleinemonde iv Estuary, a threshold water level was identified as 1.55 amsl. This was taken to be the height above sea level at which there was a maximum cover change for each macrophyte habitat. Above this water level emergent macrophyte habitat would mainly be inundated. This, together with 30 ppt salinity, was identified as the two thresholds for macrophyte change in the East Kleinemonde Estuary. From these thresholds and the 5 year dataset four biotic states were identified as State A: open and tidal, State B: closed with a water level below 1.55 m amsl and salinity between 18 to 30 ppt, State C: closed and water level above 1.55 m amsl and salinity between 18 to 30 ppt and State D: closed and water level above 1.55 m amsl and salinity above 30 ppt. Intertidal salt marsh, reeds and sedges were dominant during the open phase. Submerged macrophytes were dominant during the closed polyhaline state and macroalgae during the closed euhaline state. The high variability of abiotic factors common in TOCEs and the response of macrophyte habitat indicated that macrophytes were resilient to changing states provided they were of relatively short (< 3 months) duration. Macrophytes in the East Kleinemonde Estuary were found to have fast growth rates and large seed reserves in the sediment. The seed banks in the East Kleinemonde, as well as the adjacent temporarily open/closed West Kleinemonde Estuary were quantified for the first time in a South African estuary. The averaged data from both estuaries showed that Charophyte öospores represented almost 72 percent of the sexual propagules in the sediment with a mean öospore density of 31 306 ± 2 293 m-2. This was despite the Charophytes being sparsely located and only representing a maximum of 32.5 percent cover in the above ground vegetation. Historically there must have been stands of Charophytes in the East Kleinemonde Estuary, such that öospores could accumulate to such high density found in this study. The second highest seed density was for the intertidal salt marsh plant Sarcocornia tegetaria (18 percent) (7 929 ± 688 seed m-2), followed by the submerged angiosperm Ruppia cirrhosa (7 percent) (2 852 ± 327 seeds m-2). Although seed density did not differ significantly with sediment depth, seeds still occurred at 20 cm below the surface of the sediment providing a regeneration source in the event of sediment scouring during a flood event. Germination studies in the greenhouse showed that most seeds were viable and Sarcocornia tegetaria began to germinate after 3 days to a maximum of 82 percent after 91 days. Submerged species only germinated after 18 days with a low maximum germination of between 11 and 15 percent. This study has made an original contribution to the field of knowledge on macrophyte responses in a small TOCE as it showed that macrophyte habitats in the East Kleinemonde Estuary have a high natural variability in cover over time, they respond quickly after a disturbance event such as a mouth breach and there are large sediment seed reserves that remain viable from 2 to more than 5 years. This ensures habitat persistence even under unfavourable conditions, such as prolonged periods of mouth closure with high water level and flooding which causes loss of salt marsh species. Given this natural variability it is necessary to predict responses both spatially and temporally in order to manage and maintain ecological functioning in TOCEs. This study identified dominant macrophyte habitat for different abiotic states through the use of water level and salinity thresholds. In the determination of the freshwater requirements of any South African estuary freshwater inflow rates are provided for each estuary's past, present and possible future freshwater inflow scenarios. These flow data are generated by hydrological models and simulated monthly inflow volumes for a period of about 72 years are provided. For the East Kleinemonde freshwater requirement study for any year in that 70-odd year period, the number of high flow and low flow mouth breaches were predicted, as well as the closed state periods. The threshold water level of 1.55 m amsl was also used to filter past, present and future inflow monthly volumes to determine the frequency of the four abiotic states identified in this study. It was based on a water level/water volume equation calculation from a digital elevation model. Results showed that the total closed period in the present state was 83 percent, made up of 48 percent of the time in a polyhaline state (State C) and 35 percent in a euahaline state (State D). A second method was used to quantify available spatial habitat under different water level scenarios. A spatial model was written in Model Builder, an application in ArcGIS that allowed a series of processes to be built. A habitat map was overlaid with a bathymetric map and by selecting water level, available habitat areas were determined and empirical equations of water level versus available habitat were produced. These equations were then used to calculate the available habitat areas for monthly water level conditions from the freshwater requirement study for the past, present and two future inflow scenarios. Using both the threshold water level method and the spatial availability model method it was possible to assess the effect of the two future inflow scenarios on macrophyte habitat vi response. Scenario 1 had a 16 percent reduction in mean annual runoff (MAR) generating low flows for 88.6 percent of the time and a 3.5 percent reduction in flood events. In Scenario 2 there would be a 12 percent reduction in MAR with low flows occurring for 87.5 percent of the year, a 5.3 percent reduction in floods and an 11.5 percent reduction in the open mouth state. The model showed that Scenario 1 would have the highest submerged macrophyte area (12.56 ha versus 12.48 ha in Scenario 2), whereas Scenario 2 produced the largest mudflat and intertidal salt marsh area (7.11 ha versus 7.34 ha) due to lower water level in conjunction with the bathymetry of the estuary. A reduction in freshwater inflow to TOCEs either due to anthropogenic influences or natural precipitation cycles is one of the main threats to the optimum functioning of these estuaries. The results from this study and the two methods of assessing the effect of freshwater inflow scenarios on macrophytes in TOCEs can be integrated into the current freshwater inflow assessment methodology in South Africa, as well as adding to our understanding of the ecological functioning of these small, highly variable estuaries. The methods provide a quick assessment of macrophyte habitat associated with abiotic states under past, present and future inflow scenarios. All that is required to predict macrophyte habitat for different freshwater inflow scenarios (present, past and future) is a habitat map, a bathymetric map and the elevation range of macrophytes in the TOCE being assessed. This, together with the knowledge of response rates, provides invaluable information for the management of TOCEs to maintain their ecological functioning under altered freshwater inflow regimes.
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  • Date Issued: 2011

E-commerce as an alternative marketing channel

  • Authors: Mounsear-Wilson, Clifford
  • Date: 2011
  • Subjects: Electronic commerce -- South Africa -- Eastern Cape , Internet marketing -- South Africa -- Eastern Cape , Electronic commerce -- Technological innovations -- South Africa -- Eastern Cape , Organizational effectiveness -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:8605 , http://hdl.handle.net/10948/1615 , Electronic commerce -- South Africa -- Eastern Cape , Internet marketing -- South Africa -- Eastern Cape , Electronic commerce -- Technological innovations -- South Africa -- Eastern Cape , Organizational effectiveness -- South Africa -- Eastern Cape
  • Description: Information technology (IT) has become an integral part of the success and globalisation of business over the last two decades. It is hard to imagine how the efficiencies expected in today’s fast paced business world could possibly be achieved without the advancements in IT. The most significant of these advancements is arguably the advent of the Internet which has empowered businesses of all sizes by giving them the means to promote their products and services at a relatively low cost in markets that would previously have been inaccessible. The aim of this study was to assess whether e-commerce represents an alternative channel for a brick and mortar company wishing to follow a market penetration strategy. The study was based around a company, Canoa Eastern Cape, which trades in the office automation industry in the Eastern and Southern Cape of South Africa. The study investigated the history of Canoa Eastern Cape, focusing predominantly on the growth strategies followed by the business in the past. With a view to the future, growth strategies which could potentially be followed by Canoa Eastern Cape were also investigated. The result of these investigations was a recommendation that Canoa Eastern Cape should follow a market penetration strategy, which will see the business marketing its existing products within its current market by making use of a new distribution channel, more specifically e-commerce. In order to assess the suitability of e-commerce as a tool within a market penetration strategy a literature study was conducted to get a better understanding of ecommerce and its viability as business tool. The literature study focused on eight core concepts felt to be critical in the evaluation of e-commerce, namely: • the development of e-commerce over the past years; • the future of e-commerce; • whether e-commerce is a financial success or not; • requirements for e-commerce to be successful; iv • products that customers are prepared to buy online; • industries most affected by e-commerce; and • demographics of e-commerce users; and • e-commerce in the office automation industry. Using the information gained in the literature study as a basis from which to start, an empirical study was conducted. The objective of the empirical study was to obtain data which would be used to assess the level to which e-commerce has been adopted by consumers in the specific geographic area and whether these consumers are willing and able to make use of e-commerce as an alternative to conventional purchasing for the procurement of office automation consumables and office automation equipment. A quantitative research paradigm was adopted, making use of a structured questionnaire to gather information from the sample of Canoa Eastern Cape’s customers. The data collected from the empirical study were analysed using univariate and bivariate analysis. The findings of the empirical study suggested that: • demographics are a poor indicator of adoption of e-commerce; • there is a significant adoption rate within the sample: o 79.85 percent of the respondents reported to have used e-commerce before for personal use; and o 59.13 percentreported to have used e-commerce before for business use; • there is a high rate of willingness to use e-commerce again: o 91.09 percent of the respondents indicating that they would use e-commerce again for personal use; and o 80.18 percent indicating that they would use e-commerce again for business use; • there is a high likelihood that consumers will buy office automation consumables through an e-commerce channel, with 65.82 percentof the respondents indicating that they would be likely or very likely to buy consumables through an e-commerce channel; • there is no significant difference in the adoption rates between the three main areas within the targeted sample, that is, East London, Port Elizabeth and George and Knysna. Given the findings of the empirical study it is felt that an e-commerce solution does present a viable alternative channel for a brick and mortar company trading in the Office Automation Industry in the Eastern and Southern Cape wishing to follow a market penetration strategy.
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  • Date Issued: 2011

Economic impact studies and methodological bias : the case of the National Arts Festival in South Africa

  • Authors: Bragge, Brent Reuben
  • Date: 2011
  • Subjects: Standard Bank National Arts Festival Standard Bank National Arts Festival -- Economic aspects Performing arts festivals- Economic aspects -- South Africa Arts -- Economic aspects -- South Africa Economic impact analysis Edinburgh International Festival -- Economic aspects Klein Karoo Nasionale Kunstefees (Oudtshoorn, South Africa) -- Economic aspects Volksbladfees (Bloemfontein, South Africa) -- Economic aspects
  • Language: English
  • Type: Thesis , Masters , MEcon
  • Identifier: vital:968 , http://hdl.handle.net/10962/d1002702
  • Description: Over the course of the last three decades, it has become popular practice to evaluate tourism events like cultural festivals in financial terms, through the use of economic impact studies. This can be attributed at least in part to the notable growth in the number of festivals being held globally and, as such, a higher level of competition between festivals for the limited funding which is available. Economic impact studies, and the resultant findings, have thus become powerful tools for the lobbying of sponsorship, and it has become increasingly important that the impact calculations be as accurate as possible, so as to effectively allocate both government and private resources to projects which will be of the greatest benefit to the host region. The allocation of funding is especially vital in an area like the Eastern Cape Province of South Africa, which is faced with many financial difficulties. The allocation of public funds to an event like the National Arts Festival, which is hosted in a relatively wealthy part of the province, might be weighed against initiatives which directly benefit the poorer parts of the region. Although it is acknowledged that the benefits which are felt by the host community of a cultural event go beyond that of the financial, it is often on this basis that festivals are most easily compared. The primary goal of the thesis was to analyse the various forms of methodological bias which can exist in the economic impact analyses (EIA) associated with cultural events. Theoretical considerations were discussed, specifically regarding economic impact as a method of measuring value. Various forms of bias (including data collection, the calculation of visitor numbers, multipliers, defining the area of interest, inclusion of visitor spending, and accounting for benefits only, not costs) are put into a real-life context, through the investigation of economic impact studies conducted on three selected South African festivals (the Volksblad, the Klein Karoo Nasionale Kunstfees, and the National Arts Festival), and one international festival (the Edinburgh Festival). An in-depth comparison of two separate studies conducted at the National Arts Festival (NAF) in 2004 (by Antrobus and Snowball) and 2005 (by Saayman et al.) was made, focussing on the manner in which the economic impact was calculated. Having considered the common forms of bias, and assessing several possible reasons for the difference of approximately twenty million Rand in the advertised economic impacts, it was concluded that, most likely, the miscalculation of visitor numbers was the cause. This was confirmed when the Antrobus and Saayman methods were applied to the 2006 NAF data, and noting that the economic impact figures arrived at were strikingly similar. As such, it is advisable that extreme caution be taken when calculating visitor numbers, as they can significantly influence the outcome of an economic impact study. It is recommended that each study should also have transparent checks in place, regarding the key calculation figures, to ensure that less scrupulous researchers are not as easily able to succumb to the pressure event sponsors might impose to produce inflated impact values.
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  • Date Issued: 2011

Economics of land reform models used in Mashonaland Central Province of Zimbabwe

  • Authors: Musemwa, Lovemore
  • Date: 2011
  • Subjects: Land reform -- Zimbabwe , Agricultural productivity -- Zimbabwe , Land tenure -- Zimbabwe , Infrastructure (Economics) -- Government policy -- Zimbabwe , Land reform beneficiaries -- Zimbabwe , Land use -- Economic aspects -- Zimbabwe , Field crops -- Zimbabwe , Data envelopment analysis -- Zimbabwe , Land settlement -- Zimbabwe
  • Language: English
  • Type: Thesis , Doctoral , PhD (Agricultural Economics)
  • Identifier: vital:11168 , http://hdl.handle.net/10353/435 , Land reform -- Zimbabwe , Agricultural productivity -- Zimbabwe , Land tenure -- Zimbabwe , Infrastructure (Economics) -- Government policy -- Zimbabwe , Land reform beneficiaries -- Zimbabwe , Land use -- Economic aspects -- Zimbabwe , Field crops -- Zimbabwe , Data envelopment analysis -- Zimbabwe , Land settlement -- Zimbabwe
  • Description: The land reform that has unfolded in Zimbabwe since 1980 used different models and had diverse consequences. Since the implementation of the fast tract land reform programme in 2000, Zimbabwe experienced heavy reduction in yield and output at farm level that led to a 70% shortfall in production to meet annual food requirements (Richardson, 2005). The economic crisis in Zimbabwe has been characterized by worsening food insecurity especially in the rural areas where harvests continue to be poor. In the beef sector, Zimbabwe has failed to meet its export quota to the EU. The shortfall in production to meet annual food requirements shows a very grim situation but do not tell us about the performance of resettled farmers who now occupy much of the productive land. The broad objective of the study was to determine and compare the production efficiency of resettled farmers in Zimbabwe across land reform models. In addition, the study determined land use intensity. The study was conducted in the Mashonaland Central Province of Zimbabwe mainly because a wide variety of field crops were grown by resettled farmers. The respondents were stratified into three groups. These were: beneficiaries of land reform before 2000 (resettle scheme), fast track A1 model and fast track A2 model. The three models differ on how they were implemented and supported and this might result in different efficiencies of the models. A total of 245 copies structured questionnaire were administered on the resettled farmers from June to September 2010. Descriptive statistics was applied to the basic characteristics of the sampled households. The effect of model of land reform, gender of the household head, marital status, age of the household head, education, household size, religion, dependence ratio, whether the farmer was fulltime or part-time in farming, experience of the farmers in farming at that environment, total land size owned by the farmers and soil type on revenue per hectare and land use rate were determined using the GLM procedure of SAS (2003). Significance differences between least-square group means were compared using the PDIFF test of SAS (2003). The relationship between Revenue and land utilization was examined using the Pearson‟s correlations analysis. Dependance between response variables that had an effect on either revenue per hectare or land utilization with all the other response variables was tested using the Chi-square test for dependance. To find the effect of arable land used and herd size on revenue per hectare and land use the RSREG Procedure of SAS (2003) was used. Input oriented DEA model under the assumption of constant return to scale was used to estimate efficiency in this study. To identify factors that influence efficiency, a Tobit model censored at zero was selected. The mean land use rate varied significantly (p<0.05) with the land reform model with A2 having highest land use rate of 67%. The A1 and old resettlement households had land use rates of 53% and 46%, respectively. Sex, marital status, age of the household head, education and household size significantly affected land use (P<0.05). Revenue per hectare was not affected by any the factors that were inputted in the model. Results from the DEA approach showed that A2 farmers (large land owners) had an average technical efficiency score of 0.839, while the lowest ranking model (A1) had an average score of 0.618. Small land holders (A1 and the old resettled farmers) are on average less cost-efficient than large land owners, with a score of 0.29 for the former compared with 0.45 for the latter. From the factors that were entered in the Tobit model, age of household head, excellent production knowledge and farmer status affected technical efficiency whereas allocative efficiency was only affected by good production knowledge, farm size, arable land owned and area under cultivation. Factors which affected economic efficiency of the resettled farmers are secondary education, household size, farm size, cultivated area and arable land owned. None of the included socio-economic variables has significant effects on the allocative and economic efficiency of the resettled farmers. Thus, the allocative and economic inefficiencies of the farmers might be accounted for by other natural and environmental factors which were not captured in the model.
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  • Date Issued: 2011

Ecotherapy in post-conflict healing: a study of the experiences of ex-combatants in the Eastern Cape township of Mdantsane

  • Authors: Mbona, Sifingo
  • Date: 2011
  • Subjects: Post-traumatic stress disorder , Veterans -- Services for , Human services -- South Africa -- Eastern Cape , Environmental psychology
  • Language: English
  • Type: Thesis , Masters , M SW
  • Identifier: vital:11758 , http://hdl.handle.net/10353/331 , Post-traumatic stress disorder , Veterans -- Services for , Human services -- South Africa -- Eastern Cape , Environmental psychology
  • Description: During this research project, an attempt was made to understand the role of ecotherapy as a therapeutic model in post conflict healing. The aim was to evaluate the application and significance of ecotherapy as an intervention strategy for post conflict healing for individuals who were exposed to violent encounters during the liberation struggle. Eight respondents (involved in the arms struggle) from Mdanstane Township in the Eastern Cape, were taken through a series of workshops as part of an ecotherapy healing process. The research concluded that all the participants had suffered from some form of traumatic stress because of their exposure to violence and violent experiences. Moreover, on closer examination the situation of ex-combatants proved to be more complex and often volatile, due to the absence of social support, loss of social status, absence of economic, employment opportunities, and the dislocation from their families and communities. Subsequent to the ecotherapy intervention, a positive outlook amongst the participants was recorded. Furthermore, there was an indication of a significant increase in their sense of self-worth and personal development, which influenced the manner in which the participants viewed the world, related to their families or communities and responded to life in general. Essentially, the research findings, conclusions, and recommendations contributed towards a better understanding of ex-combatants and the value that could be derived from ecotherapy as a post conflict healing method for individuals and groups exposed to violence and trauma.
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  • Date Issued: 2011

Educating users about information security by means of game play

  • Authors: Monk, Thomas Philippus
  • Date: 2011
  • Subjects: Computer security , Educational games -- Design , Computer networks -- Security measures
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:9748 , http://hdl.handle.net/10948/1493 , Computer security , Educational games -- Design , Computer networks -- Security measures
  • Description: Information is necessary for any business to function. However, if one does not manage one’s information assets properly then one’s business is likely to be at risk. By implementing Information Security controls, procedures, and/or safeguards one can secure information assets against risks. The risks of an organisation can be mitigated if employees implement safety measures. However, employees are often unable to work securely due to a lack of knowledge. This dissertation evaluates the premise that a computer game could be used to educate employees about Information Security. A game was developed with the aim of educating employees in this regard. If people were motivated to play the game, without external motivation from an organisation, then people would also, indirectly, be motivated to learn about Information Security. Therefore, a secondary aim of this game was to be self-motivating. An experiment was conducted in order to test whether or not these aims were met. The experiment was conducted on a play test group and a control group. The play test group played the game before completing a questionnaire that tested the information security knowledge of participants, while the control group simply completed the questionnaire. The two groups’ answers were compared in order to obtain results. This dissertation discusses the research design of the experiment and also provides an analysis of the results. The game design will be discussed which provides guidelines for future game designers to follow. The experiment indicated that the game is motivational, but perhaps not educational enough. However, the results suggest that a computer game can still be used to teach users about Information Security. Factors that involved consequence and repetition contributed towards the educational value of the game, whilst competitiveness and rewards contributed to the motivational aspect of the game.
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  • Date Issued: 2011

Effect of alkaline pre-treatments on the synergistic enzymatic hydrolysis of sugarcane (Saccharum officinarum) bagasse by Clostridium cellulovorans XynA, ManA and ArfA

  • Authors: Beukes, Natasha
  • Date: 2011
  • Subjects: Sugarcane -- Biotechnology Lignocellulose -- Biotechnology Renewable energy sources Hydrolysis Enzymes
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3952 , http://hdl.handle.net/10962/d1004011
  • Description: The continual increase in industrialization and global population has increased the dependency and demand on traditional fossil fuels for energy; however, there are limited amounts of fossil fuels available. The slow depletion of fossil fuels has sparked a fresh interest in renewable sources such as lignocellulose to produce a variety of biofuels, such as biogases (e.g. methane), bioethanol, biodiesel and a variety of other solvents and economically valuable by-products. Agricultural crop wastes produced in surplus are typically lignocellulosic in composition and thus partially recalcitrant to enzymatic degradation. The recalcitrant nature of plant biomass and the inability to obtain complete enzymatic hydrolysis has led to the establishment of various pre-treatment strategies. Alkaline pre-treatments increase the accessibility of the exposed surface to enzymatic hydrolysis through the removal of acetyl and uronic acid substituents on hemicellulose. Unlike the use of steam and acid pre-treatments, alkaline pre-treatments solubilize lignin and a small percentage of the hemicellulose, increasing enzyme accessibility and thus the hydrolysis of lignocellulose. The majority of Clostridium cellulovorans associated enzyme synergy studies have been devoted to an understanding of the cellulolytic and hemi-cellulolytic degradation of plant cell walls. However, little is known about the effect of various physical and chemical pre-treatments on the synergistic enzymatic degradation of plant biomass and possible depolymerization of plant cell walls. This study investigates the use of slake lime, sodium hydroxide and ammonium hydroxide to pre-treat sugarcane bagasse under mild conditions and elucidates potentially important synergistic associations between the C. cellulovorans enzymes for the enhanced degradation of lignocellulose. The primary aims of the study were addressed using of a variety of techniques. This included suitable vector constructs for the expression and purification of recombinant C. cellulovorans enzymes, identification of the effects of various pre-treatments on enzyme synergy, and identification of the resultant reducing sugars and phenolic compounds (released during the pre-treatment of the bagasse). This study also made use of physical and chemical pre-treatment methods, protein purification using affinity, high performance liquid and thin layer chromatography, mass spectrometry, sodium dodecyl sulphate and fluorophore-assisted polyacrylamide gel electrophoresis (FACE) , enzymatic degradation and synergy studies with various substrates indirectly using the 3, 4-dinitrosalicylic acid (DNS) reducing sugar assay. From this investigation, the following conclusions were made: alkaline pre-treatment successfully solublised, redistributed and removed lignin from the bagasse, increasing the digestibility of the substrates. In summary, the most effective pre-treatment employed 0.114 M ammonium hydroxide / gram bagasse at 70°C for 36 hours, followed by hydrolysis with an enzyme cocktail containing 25% ManA and 75% XynA. This increased the production of sugars approximately 13-fold. Analysis of the sugars produced by the synergistic hydrolysis of sugarcane bagasse (SCB) indicated the presence of xylose, indicating that the enzymes are potentially bifunctional under certain conditions. This study indicated that the use of mild pre-treatment conditions sufficiently removed a large portion of lignin without affecting the hemicellulose moiety of the SCB. This facilitated the potential use of the hemicellulose component for the production of valuable products (e.g. xylitol) in addition to the production of bioethanol. Thus, the potential use of additional components of holocellulose may generate an additional biotechnological benefit and allow a certain degree of flexibility in the biofuel industry, depending on consumer and industrial needs.
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  • Date Issued: 2011

Effect of BT maize on earthworm activity, silage quality and residue decomposition in the central Eastern Cape

  • Authors: Kamota, Agathar
  • Date: 2011
  • Subjects: Corn -- South Africa -- Eastern Cape , Corn -- Silage , Bacillus thuringiensis , Earthworm culture , Biomass , Plant proteins
  • Language: English
  • Type: Thesis , Masters , MSc Agric (Crop Science)
  • Identifier: vital:11863 , http://hdl.handle.net/10353/413 , Corn -- South Africa -- Eastern Cape , Corn -- Silage , Bacillus thuringiensis , Earthworm culture , Biomass , Plant proteins
  • Description: There are concerns that genetic modification of maize with Bacillus thuringiensis may influence its structural and chemical composition which, together with the Cry1Ab proteins, may affect agro-ecosystem processes and feed quality. This study was aimed at investigating the expression of Cry1Ab protein in leaves, stems and roots of Bt maize and the effect of genetic modification (MON810) on activity of earthworms, silage quality and decomposition of residues in the field. In 2009/10 four maize cultivars; DKC61-25B, DKC61-24, PAN6Q-321B and PAN6777 were planted. Expression of Cry1Ab in leaves, stems and roots was analyzed at 6, 8, 10 and 12 weeks after planting (WAP). Earthworms were also sampled from the same treatments at 6, 9 and 18 WAP. Two silage experiments were conducted using maize cultivars, DKC80-12B and DKC80-10 produced in the 2008/09 season and DKC61-25B, DKC61-24, PAN6Q-321B and PAN6777, produced in 2009/10. The silage was sampled at 0, 2, 4, 8, 15 and 42 days in 2008/09 and 0, 8 and 42 days in 2009/10 and analyzed for Ash Free Dry Matter, Crude Fiber, Neutral Detergent Fiber, Acid Detergent Fiber, Acid Detergent Lignin, Crude Protein and Total Digestible Nutrients. Two litter-bag decomposition studies were also carried out (i) in 2008 (surface applied) using maize cultivars DKC80-12B, DKC80-10 and DKC6-125 residues and (ii) in 2009 (soil incorporated) using DKC75-15B, CRN3505, PAN6Q-321B v and PAN6Q-121. Ash-free dry matter and Cry1Ab protein were measured throughout the incubation time. There were no differences between DKC61-25B and PAN6Q-321B in terms of expression of Cry1Ab in leaves, stems and roots over time. The Cry1Ab expression levels were in decreasing order: leaves > stems > roots. No effects of Bt maize on earthworm numbers and biomass were observed. There were no differences in all silages parameters except NDF and ADF, which were higher in the Bt maize silage than that of the non-Bt maize from the 2008/09 season. The Cry1Ab levels were essentially not reduced during ensiling. The maize residues (both Bt and non-Bt maize) degraded to similar levels, either when surface-applied or incorporated into soil but soil-incorporated residues decomposed faster than surface-applied ones. Cry1Ab degraded as the plant matrix decomposed. The findings suggested that maize genetically modified with the Bt MON810 event can be grown in the Central Eastern Cape without affecting earthworm numbers and biomass, silage quality and decomposition of maize residues.
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  • Date Issued: 2011

Effect of nanoparticles on the photophysicochemical behaviour of metallophthalocyanines

  • Authors: Moeno, Sharon Keitumetse Gail Mpheletso
  • Date: 2011 , 2011-03-30
  • Subjects: Phthalocyanines Nanoparticles Photochemistry Quantum dots
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4310 , http://hdl.handle.net/10962/d1004968
  • Description: The synthesis, spectroscopic characterization, and studies of the photophysicochemical behaviour of selective anionic, cationic and neutral metallophthallocyanine (MPc) complexes were carried out and the results are presented herein. Studies on the effect of the central metal ion, the solvent used and the presence of nanoparticles on the photophysicochemical properties were conducted. The findings showed that the photophysicochemical parameters were mostly enhanced in the presence of central metal ions of high atomic numbers and also in the presence of nanoparticles. It was also observed that solvents that encouraged the monomericity of the MPc complexes also lead to improved photophysical and photochemical behaviour. CdTe quantum dots (QDs) stabilized with mercaptocarbonic acids were also observed to cause stimulated emission of the MPcs through Förster resonance energy transfer (FRET) thus acting as energy donors while the respective MPc acted as energy acceptors in all the FRET studies. FRET was observed following the photoexcitation of QDs for all monomeric anionic MPcs but it was also shown to occur for some cationic MPcs in organic media. Both the substituent and solvent used were found to exert a strong influence on the occurrence of FRET. Other cationic MPcs however showed different behaviour in the presence of the meraptocarbonic stabilized CdTe QDs; with the cationic porphyrazine giving clear indications of Pc ring reduction. The rest of the cationic MPcs did not give clear evidence of Pc ring reduction, instead they showed signs of aggregate formation possibly from the assembly of electrostatic ion pair complexes which could result in reduction of the quaternized pyridinium ring of the substituent. Both the QDs and the MPc complex emission spectra were significantly quenched for each in the presence of the other. Stern-Volmer quenching studies indicated that both static and dynamic quenching of the QDs in the presence of MPcs took place. The fluorescence lifetimes of the mercaptopropionic acid (MPA) capped CdTe QDs in the presence of various MPc complexes showed quenching of mostly the longer lifetimes of the QDs in the presence of MPcs suggesting that the surface defects and states are involved in the interaction of the QDs and MPcs. An MPc complex terminating in thio tethers was employed in the conjugation to AuNPs. Spectroscopic and microscopic studies confirmed the formation of the MPc-AuNP conjugate which was also shown to exhibit improved photophysicochemical properties compared to the free MPc.
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  • Date Issued: 2011

Effect of turbidity on the foraging success of Glossogobius callidus (Teleostei: Gobiidae)

  • Authors: Parkinson, Matthew C , Booth, Anthony J
  • Date: 2011
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/124375 , vital:35600 , https://doi.org/10.2989/16085914.2011.589120
  • Description: Particles suspended in water attenuate the light that passes through it via absorption or scattering (Utne-Palm 2002). For example, whereas algae absorb specific wavelengths of light necessary for photosynthesis, inorganic suspensoids tend to scatter light (Radke and Gaupisch 2005). This results in lowered ambient light levels and reduces the visual acuity of aquatic organisms. From a fish’s perspective, an increase in water turbidity has the potential to alter visually-mediated reproductive behaviours (Järvenpää and Lindström 2004), predator avoidance (Meager et al. 2006) and foraging success negatively (Utne-Palm 2002, Rowe et al. 2003, Sweka and Hartman 2003, Stuart-Smith et al. 2004). The foraging success of various fish species was affected by increased turbidity through decreasing predator–prey encounter rates (Sweka and Hartman 2003) and through decreasing visual acuity whereby the distance at which prey are visually detected is reduced (Utne-Palm 2002).
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  • Date Issued: 2011

Effectiveness of ICT education in the Northern school area of Port Elizabeth

  • Authors: Mooi, Alicia Tenjiswa
  • Date: 2011
  • Subjects: Educational technology -- South Africa -- Eastern Cape , Computer-assisted instruction -- South Africa -- Eastern Cape , Educational innovations -- Technological innovations -- South Africa -- Eastern Cape , Communication -- Technological innovations
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:9049 , http://hdl.handle.net/10948/1605 , Educational technology -- South Africa -- Eastern Cape , Computer-assisted instruction -- South Africa -- Eastern Cape , Educational innovations -- Technological innovations -- South Africa -- Eastern Cape , Communication -- Technological innovations
  • Description: The use of information communication technology in the 21st Century is very important. The skills and knowledge of using these technologies should start at high school level, as it is at this stage where learners are equipped for tertiary education and the business world. This study seeks to answer how much ICT is used at the average school in Port Elizabeth and how effective such use is. South Africa is one of the countries in the whole world that is still behind in using the new technology. Learners from high school still enter university with no knowledge of how to use a computer. This becomes a problem in the world of technology as almost everything is done using technology. It also becomes a big problem when learners look for jobs in the business world. An active learning theory has been used on the study because, if learners can learn and have access computer at school, life will be easy for both learners and teachers, there would be co-operation and discussion and the fast way of doing school work. For the purpose of the study a qualitative research method has been used to ensure that answers are received straight from, teachers and learners for evidence. It is therefore clear that there are schools in South Africa that still needs the attention of the government in terms of getting access to computers and to have professional teachers for teaching the subject. The government has a responsibility of making sure that all learners and teachers in high schools have access to computers and internet. This will improve the working and learning conditions of both parties involved.
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  • Date Issued: 2011

Effectiveness of integrated quality management systems for teachers in the department of education: Butterworth district

  • Authors: Sihlali, Mzuzile
  • Date: 2011
  • Language: English
  • Type: Thesis , Masters , MPA
  • Identifier: vital:8273 , http://hdl.handle.net/10948/d1015984
  • Description: The purpose of this research was to investigate the effectiveness of IQMS amongst teachers in the Butterworth district. Using a convenient sample of 79 senior secondary school teachers, a survey research design was used to collect both quantitative as well as qualitative data on the effectiveness of IQMS. The formulation of statements on the effectiveness of IQMS was informed by the levels of effectiveness of the Kirkpatrick’s model. A likert scale was used to rate the effectiveness of IQMS with respect to teachers’ views on the various statements that sought to measure the effectiveness of IQMS. The narratives of teachers on the SWOT analyses constituted qualitative data which was used to corroborate and contradict trends from the quantitative findings. Thus, SWOT analysis results were used to validate quantitative findings. In analysing quantitative data, descriptive statistics were employed to look at the distribution of the responses and overall trends. Significant differences in terms of gender, age, employment status, length of service, and the highest tertiary qualification were computed by the SPSS software. The SWOT analyses results from the open-ended questions were analysed through extraction of themes, categories and patterns. The quantitative findings suggested that IQMS is an effective evaluation instrument though the qualitative SWOT analyses results suggested otherwise. The study’s findings highlighted areas where IQMS is potentially effective, areas where there are challenges in the implementation of IQMS, and niches for intervention. The study has implications for IQMS policy and programme administrators in the district offices, school principals and teachers in the school sites, as well as implications for further research.
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  • Date Issued: 2011

Effects of Acacia karroo supplementation on the quality of meat from Xhosa lopeared goats

  • Authors: Ngambu, Simthembile
  • Date: 2011
  • Subjects: Goats -- Nutrition -- South Africa , Food -- Sensory evaluation , Goat meat -- South Africa , Goats -- Feeding and feeds -- South Africa , Meat -- Quality -- South Africa , Goats -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MSc Agric (Animal Science)
  • Identifier: vital:11808 , http://hdl.handle.net/10353/450 , Goats -- Nutrition -- South Africa , Food -- Sensory evaluation , Goat meat -- South Africa , Goats -- Feeding and feeds -- South Africa , Meat -- Quality -- South Africa , Goats -- South Africa -- Eastern Cape
  • Description: Effects of Acacia karroo supplementation on meat quality of Xhosa Lop-Eared goats The objective of the study was to determine the effects of A. karroo supplementation on the quality of meat from Xhosa lop-eared goats. Eighteen castrated 4-month-old Xhosa lop-eared male kids were kept at the University of Fort Hare Farm until slaughter. At the beginning of the experiment the goats had a mean body weight of 13.5 ± 0.31 kg (mean ± S.E.) and a mean body condition score (BCS) of 3.3 ± 0.16 (mean ± S.E.). From birth until weaning the kids were kept on natural pastures with their mothers. After weaning the goats were housed in an open sided barn for a period of 60 days, and were fed 500 g/head/day of Medicago sativa hay covering their maintenance and growth needs. For the purpose of the experiment, the goats were randomly divided into two balanced treatment groups of nine goats each, supplemented group (AK) and non-supplemented group (NS). The supplemented group received an additional 200g per head per day of fresh A. karroo leaves collected each day for two months. Supplementary feed was given to the goats individually in feeding troughs. The kids were slaughtered at 60 days old and samples for meat quality assessment were taken from the Longistimus dorsi muscle. The effect of A. karroo supplementation on meat quality measurements such as ultimate pH, colour and cooking losses of meat from indigenous Xhosa lop-eared goats were determined. The effect of A. karroo supplementation on the consumer sensory characteristic scores of the meat from the indigenous Xhosa lop-eared breed was also determined. There was a significant effect of the A. karroo supplementation on the meat quality measurements except for L* and a* colour coordinates. Meat from the A. karroo supplemented goats had lower pH and cooking loss scores than that of the non-supplemented goats. Acacia karroo supplementation improves meat tenderness and juiciness. There were no significant effects of A. karroo supplementation on the flavour and off- iv flavours of the meat from the supplemented goats. However, thermal preparation and consumer background had a significant effect on the meat sensory characteristics. The cooked meat had significantly higher sensory scores than the roasted meat. Female consumers reported higher sensory scores than male consumers. Consumers of different tribes and ages also reported significantly different sensory scores of meat from indigenous Xhosa lop-eared goats. Therefore, this study indicated that A. karroo supplementation can be fed to the Xhosa lop-eared goats to improve their meat quality.
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  • Date Issued: 2011

Effects of colours, shapes and icons on performance and familiarity

  • Authors: Dambuza, Inga Yola
  • Date: 2011
  • Subjects: Industrial hygiene -- Research -- South Africa , Industrial safety -- Research -- South Africa , Industrial hygiene -- Standards -- South Africa , Human engineering -- Research -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5117 , http://hdl.handle.net/10962/d1005195 , Industrial hygiene -- Research -- South Africa , Industrial safety -- Research -- South Africa , Industrial hygiene -- Standards -- South Africa , Human engineering -- Research -- South Africa
  • Description: Occupational injuries and illnesses remain to be a heavy burden on workers and employees in industrial developing and industrially developed societies, and health and safety in workplaces continues to be an important issue for ergonomists. Steps are being taken to stimulate health and safety agendas and to discover ways in which health and safety in industries can be improved. The main responsibility of employers is to provide employees with information, instructions and training that they required to carry out their work tasks in a healthy, practical and safe manner. The role of education as a countermeasure to occupational injury and illness is being re-examined by health and safety practitioners and safety training is being considered as a vital part of accident prevention strategies. Effective training programmes should guarantee that workers possess the skills they require to complete their tasks in a safe and healthy manner. Very little is known about the type and quality of training workers undergo and how that training affects the safety outcomes of companies. There has been an attempt over the past 20 years to increase the research on safety communications and a great deal of this research has been focused on safety warnings; with the greatest attention been placed on the components of safety signs, such as colours, size, shapes and icons. The effects of these components on comprehension with relation to age and education have not received the same amount of attention. The impact of familiarity on safety warnings with respect to age and education has also received very little attention; despite the knowledge that familiarity has been shown to increase the noticing of warnings and the comprehension of safety information. Despite the increase in the research on safety communication, the literature and research in South Africa is scarce. Studies present in South Africa do not encompass the comprehension of safety signs or the ability of individuals with different age and education levels to learn the information included in the signs. Due to the multi-linguistic nature of South Africa and the fact that South Africa is an Industrially Developing Country (IDC) with high levels of illiteracy, issues such as the comprehension of safety information must be addressed. Therefore, the objectives of this study were to investigate the effects of safety sign attributes on learning and familiarity, in subjects that differed in age and education levels. These effects were investigated through measuring the reaction and response times of the different subject groups, as well as the number of components in the safety signs that were recalled correctly. The combined results of these responses were used as a measure for familiarity. A set of signs was designed for the study by the researcher using three different colours, three different shapes, three different icons and text. Certain variables were omitted from some signs to create the test pool and the eight conditions that were tested in a laboratory setting. Each condition contained different components of the designed signs and 60 subjects were used to test these conditions. The subjects were placed in groups according to their age and level of education. Subjects were required to learn a set of 64 signs, either “With Occlusion” or “Without Occlusion”, and asked to recall the meanings of the components in the signs. Reaction time, response time and error rate were measured from the responses. The results showed that the conditions resulted in different reaction times, response times and error rates for all subjects. The signs containing a combination of shapes and text resulted in the best performance. Age and education were found to have a significant effect on various performance criteria as did the method in which the signs were displayed (Occlusion and No Occlusion). The increased repetitions and sessions elicited lower reaction times, response times and error rates. The conclusions drawn from this study suggest that different attributes be considered carefully when subjects are expected to learn and recall information in safety signs. The results also highlighted the need to increase the exposure of individuals to safety signs in order to increase familiarity and ultimately improve the recall and comprehension of the attributes.
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  • Date Issued: 2011

Effects of genetically modified maize (MON810) and its residues on the functional diversity of microorganisms in two South African soils

  • Authors: Puta, Usanda
  • Date: 2011
  • Subjects: Genetically modified foods -- South Africa , Transgenic plants -- South Africa , Crops -- Genetic engineering -- South Africa , Soil microbiology -- South Africa , Microorganisms , Microbial ecology , Rhizosphere -- Microbiology , Vesicular-arbuscular mycorrhizas , Corn -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc (Microbiology)
  • Identifier: vital:11250 , http://hdl.handle.net/10353/419 , Genetically modified foods -- South Africa , Transgenic plants -- South Africa , Crops -- Genetic engineering -- South Africa , Soil microbiology -- South Africa , Microorganisms , Microbial ecology , Rhizosphere -- Microbiology , Vesicular-arbuscular mycorrhizas , Corn -- South Africa
  • Description: Genetically modified (GM) crops are commercially cultivated worldwide but there are concerns on their possible negative impacts on soil biodiversity. A glasshouse study was conducted to determine effects of Bt maize residues on soil microbial diversity. Residues of Bt maize (PAN 6Q-308B) and non-Bt maize (PAN 6Q-121) were incorporated into the soil and corresponding maize seeds planted. The treatments were replicated three times. Fertilizer and water application were similar for both treatments. Rhizosphere and bulk soil was destructively sampled from each treatment and analyzed for microbial community level physiological profiles using Biolog plates with 31 different carbon substrates. Absorbance in the Biolog plates was recorded after 72 h of incubation at 20oC. Arbuscular mycorrhizal fungi spore counts were also determined. Field studies were conducted at the University of Free State and University of Fort Hare Research Farms to determine the effects of growing Bt maize on soil microbial diversity. One Bt maize cultivar (PAN6Q-308B) and non-Bt maize (PAN6Q-121) were grown in a paired experiment at University of Free State farm, while two Bt maize (DKC61-25B and PAN6Q-321B) and their near-isogenic non-Bt maize lines (DKC61-24 and PAN6777) were grown in a randomized complete block design with three replicates. Fertilization, weed control and water application, were similar for both Bt maize cultivars and their non-Bt maize counterparts. Rhizosphere soil samples were collected by uprooting whole plants and collecting the soil attached to the roots. The samples were analysed for microbial diversity and for arbuscular mycorrhizae fungal spore counts. Principal component analysis showed that soil microbial diversity was affected more by sampling time whereas genetic modification had minimal effects. Presence of residues also increased the diversity of microorganisms. Mycorrhizal fungal spores were not affected by the presence of Bt maize residues. Growing Bt maize had no effect on the soil microbial diversity in the rhizosphere.
  • Full Text:
  • Date Issued: 2011

Effects of habitat patch size and isolation on the population structure of two siphonarian limpets

  • Authors: Johnson, Linda Gail
  • Date: 2011
  • Subjects: Siphonaria , Limpets , Population biology , Marine ecology , Habitat selection , Animals -- Dispersal , Ecological heterogeneity , Animal populations , Biodiversity
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5679 , http://hdl.handle.net/10962/d1005364 , Siphonaria , Limpets , Population biology , Marine ecology , Habitat selection , Animals -- Dispersal , Ecological heterogeneity , Animal populations , Biodiversity
  • Description: Habitat fragmentation is a fundamental process that determines trends and patterns of distribution and density of organisms. These patterns and trends have been the focus of numerous terrestrial and marine studies and have led to the development of several explanatory hypotheses. Systems and organisms are dynamic and no single hypothesis has adequately accounted for these observed trends. It is therefore important to understand the interaction of these processes and patterns to explain the mechanisms controlling population dynamics. The main aim of this thesis was to test the effect of patch size and isolation on organisms with different modes of dispersal. Mode of dispersal has previously been examined as a factor influencing the effects that habitat fragmentation has on organisms. Very few studies have, however, examined the mode of dispersal of marine organisms because it has long been assumed that marine animals are not directly influenced by habitat fragmentation because of large-scale dispersal. I used two co-occurring species of siphonariid limpets with different modes of dispersal to highlight that not only are marine organisms affected by habitat fragmentation but that they are affected in different ways. The two species of limpet, Siphonaria serrata and Siphonaria concinna, are found within the same habitat and have the same geographic range along the South African coastline, however, they have different modes of dispersal and development. The effect of patch size on organism density has been examined to a great extent with varied results. This study investigated whether habitat patch size played a key role in determining population density and limpet body sizes. The two species are found on the eastern and southern coasts of South Africa were examined across this entire biogeographic range. Patch size was found to have a significant effect on population density of the pelagic developer, S. concinna, but not the direct developing S. serrata. Patch size did play a role in determining limpet body size for both species. S. concinna body size was proposed to be effected directly by patch size whilst S. serrata body size was proposed to be affected indirectly by the effects of the S. concinna densities. The same patterns and trends were observed at five of the seven examined regions across the biogeographic range. The trends observed for S. concinna with respect to patch size conform to the source-sink hypothesis with large habitat patches acting as the source populations whilst the small habitat patches acted as the sink populations. Many previous studies have focused on the effects of habitat patch size at one point in time or over one season. I tested the influence of habitat patch size on the two species of limpets over a period of twelve months to determine whether the trends observed were consistent over time or whether populations varied with time. S. concinna showed a consistently significant difference between small and large patches; whilst S. serrata did not follow a consistent pattern. The mode of dispersal for the two limpets was used to explain the different trends shown by the two species. This examination allowed for the determining of source and sink populations for S. concinna through the examination of fluctuations in limpet body sizes and population densities at small and large habitat patches over twelve months. The direct developing S. serrata trends could not be explained using source-sink theory, as populations were independent from one another. S. serrata demonstrated body size differences at small and large patches which, may be explained by interspecific and intraspecific competition. Habitat isolation is known to play an important role in determining the structure of assemblages and the densities of populations. In this study the population density of the pelagic developing S. concinna showed a weak influence of degree of isolation whilst that of the direct developing S. serrata did not, which may be because of habitat patches along the South African coastline not having great enough degrees of isolation. The population size-structure was influenced directly influenced by isolation for S. concinna, whilst the different population size structure for S. serrata may be explained by assemblage co-dependence. The mode of dispersal showed effects on the relationship of population density and population size-structure with habitat size and isolation. This study indicates the importance of investigating patterns and processes across a range of spatial and temporal scales to gain a comprehensive understanding of factors effecting intertidal organisms.
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  • Date Issued: 2011

Effects of polarization in a distributed raman fibre amplifier

  • Authors: Muguro, Kennedy Mwaura
  • Date: 2011
  • Subjects: Fiber optics , Polarization (Light) , Optical communications , Optical amplifiers , Raman effect
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:10544 , http://hdl.handle.net/10948/d1014621
  • Description: The need to exploit the large fibre bandwidth and increase the reach has seen the application of the Raman fibre amplifier (RFA) become indispensable in modern light wave systems. The success and resilience of RFAs in optical communication is deeply rooted in their unique optical properties and new technologies which have allowed the amplifier to come of age. However, the full potential of RFAs in optical communication and other applications are yet to be realized. More so are its polarization properties which still remain largely unexploited and have not been fully understood. In this work, fundamental issues regarding distributed RFA have been investigated with the aim of acquiring a better understanding of the amplifier polarization characteristics which have potential applications. In particular the effects of polarization mode dispersion (PMD) and polarization dependent loss (PDL) have been demonstrated both by simulation and experiment. The possibility of Raman polarization pulling in single mode fibres (SMFs) has also been addressed. Polarization sensitivity of RFA has been known for a long time but the clear manifestation of it has become evident in the advent of modern low PMD fibre. Unlike EDFAs which make use of special doped fibre, RFAs require no special fibre for operation. Besides, RFA uses a very long length of fibre and as such the fibre polarization characteristics come into play during amplification. In the demonstrations presented in this thesis a fibre of PMD coefficient < 0.05 pskm-1/2 was regarded as low PMD fibre while one having coefficient ≥ 0.05 pskm-1/2 was categorized to have high PMD unless otherwise stated. Several experiments were performed to evaluate the RFA gain characteristics with respect to fibre PMD and the system performance in the presence of noise emanating from amplified spontaneous emission (ASE). Analysis of Raman gain statistics was done for fibres of low and high PMD coefficients. The statistics of PDG and on-off gain were eventually used to demonstrate the extraction of PMD coefficients of fibres between 0.01- 0.1 pskm-1/2 using a forward pumping configuration. It was found that, at increasing pump power a linear relationship exists between forward and backward signal gain on a dB scale. The interaction of PDL and Raman PDG in the presence of PMD were observed at very fundamental level. It was found the presence of PDL serves to reduce the available on-off gain. It was also established that the presence of PMD mediates the interaction between PDG/PDL. When PMD is high it reduces PDG but the presence of PDL introduces a wavelength dependent gain tilting for WDM channels. Further analysis revealed that signal polarization is influenced by the pump SOP due to the pulling effect which is present even at moderate pump power.
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  • Date Issued: 2011

Effects of pre-slaughter handling on pork quality from a smallholder abbatoir

  • Authors: Gajana, Christian Sabelo
  • Date: 2011
  • Subjects: Meat cuts -- Standards , Pork -- Quality
  • Language: English
  • Type: Thesis , Masters , MSc Agric (Animal Science)
  • Identifier: vital:11174 , http://hdl.handle.net/10353/434 , Meat cuts -- Standards , Pork -- Quality
  • Description: Effects of pre-slaughter handling on pork quality from a smallholder abattoir By Christian Sabelo Gajana A total of 158 pork samples from Landrace and Large White pigs were collected from Nxuba Municipal abattoir to determine the effects of pre-slaughter handling on pork quality. Technological quality attributes of pork such as pHu, L*, a*, b*, WBSF values, TL%, CL% EL% were determined. Breed differences were observed in ultimate pH (pHu) and redness (a*) with meat from the Large White having higher pHu and lower a* values than meat from the Landrace. Meat from pigs slaughtered in spring season had the highest (P<0.05) shear force values (27.6±1.58) while the lowest shear force values (18.5±1.58) were found in meat from pigs that were slaughtered in the autumn season. The lowest pHu and highest a* values were found in meat from 9 month-old pigs (5.3±0.07). The 6, 9 and 10 months had highest (P<0.05) than 7 and 8 months old pigs. Cooking loss and evaporation loss increased with age groups. Only distance and transportation time had a positive relationship to TL% of pork whilst no significant relationship was reported between all the other pre-slaughter variables and technological quality attributes of pork. Highest risks of PSE occurrences were observed with more space allowance of 0.4 m2 per 100 kg during transportation. Reduced risks of PSE occurrences were observed with space allowance of 0.35 m2 per 100 kg. The pHu were positively correlated to WBSF values (P < 0.001). The L* values were positively correlated to b* (P < 0.001), and negatively correlated to a* while CL and EL were positively correlated to L*. In the current study, a* values were positively correlated to b* (P < 0.001) but negatively correlated to EL (P < 0.01). There were iv positive correlations between CL and EL, Both CL and EL were positively correlated to WBSF values. The first four principal components (PCs) explained about 95% of the total variability for technological quality attributes of pork. It can be concluded that pig breeds vary in pHu and considerations should be made on different seasons of slaughter when assessing pork quality. Precautions should also be made on age categories of animal when improving the quality of pork. Transportation time, distance, stocking density, temperature and lairage time did not show significant relationship with technological quality attributes measured; except for transportation time and distance travelled which had a positive relationship with TL%. The risk of PSE increased with more space availability more than 0.4 m2 per 100 kg pig, but stocking density of 0.35 m2 per 100 kg was an ideal reduce the risk of PSE pork.
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  • Date Issued: 2011

Effects of selected modes of digital distribution on music consumerism, with reference to the album format

  • Authors: Du Preez, Liska
  • Date: 2011
  • Subjects: Sound -- Recording and reproducing -- Digital techniques , Music -- Technological innovations , Music and the Internet
  • Language: English
  • Type: Thesis , Masters , MMus
  • Identifier: vital:8504 , http://hdl.handle.net/10948/1427 , Sound -- Recording and reproducing -- Digital techniques , Music -- Technological innovations , Music and the Internet
  • Description: In this digital age many listeners of music now purchase albums from online digital music stores instead of buying a physical album from the record store. This has created a concern with many regarding the future of the album as a physical medium. This study investigates the impact of the possible death of the album on certain listening habits, the activity of record collecting, the creation of large-scale musical works, music consumerism, and its implications for the creative process on music as art and sound-recording quality. Three realisations have led to the problem statement. Firstly, the album might not have a future in the digital age. Secondly, downloadable songs might not be able to recreate an album experience. The third realisation is that the possible death of the album could create new, exciting challenges to artists as they strive to create art. This study is exploratory in nature - and no hypothesis was generated. The research necessitates qualitative, exploratory, descriptive and contextual approaches. Furthermore, the investigation has led to the collection of mostly new data, constituting a “primary data design” through the implementation of qualitative listening experiments and a focus group, using full-time NMMU students between 18 and 25 years of age. It is herein argued that digital distribution might possibly have an effect on the perception of the album format and might possibly still be a relevant listening experience, valued by young people. Singles and albums are collectable; and good albums are considered artistic and comparable to the large-scale musical works of the past. If the concept of an album does not die out, then high fidelity formats should be able to re-invent the album experience. Listening experiences other than the album experience do exist, and they could generate new ways for artists to create musical art.
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  • Date Issued: 2011

Electrochemical behavior of phthalocyanines containing high oxidation state central metals

  • Authors: Chauke, Vongani , Arslanoglu, Yasin , Nyokong, Tebello
  • Date: 2011
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/247111 , vital:51547 , xlink:href="https://doi.org/10.1016/j.poly.2011.05.028"
  • Description: The syntheses of 2,(3)-(peripheral) and 1,(4)-(non-peripheral) (2-mercaptopyridine)phthalocyanine complexes of titanium(IV) oxide (5a and 6a, respectively), vanadium(IV) oxide (7a and 8a, respectively) and tantalum(V) hydroxide (9a, peripheral only) and their electrochemical characterization are presented in this report. Their electrochemistry is compared to that of thiophenyl and thiobenzyl substituted derivatives. The non-peripherally substituted complexes are more difficult to reduce than peripherally substituted derivatives. In addition, the mercaptopyridine substituted derivatives are more difficult to reduce compared to benzylmercapto and phenylmercapto derivatives, and aryl easier reduce than alkyl substitution. Spectroelectrochemistry of the complexes confirmed metal and ring redox processes for TaPc and TiPc derivatives and ring based processes only for VPc complexes.
  • Full Text:
  • Date Issued: 2011
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