Influence of mite predation on the efficacy of the gall midge Dasineura sp. as a biocontrol agent of Australian myrtle Leptospermum laevigatum (Myrtaceae) in South Africa
- Mdlangu, Thabisa Lynette Honey
- Authors: Mdlangu, Thabisa Lynette Honey
- Date: 2010
- Subjects: Dasyneura leguminicola , Myrtaceae -- South Africa , Mites as biological pest control agents , Pests -- Biological control , Biological pest control agents , Predation (Biology)
- Language: English
- Type: Thesis , Masters , MSc (Zoology)
- Identifier: vital:11789 , http://hdl.handle.net/10353/272 , Dasyneura leguminicola , Myrtaceae -- South Africa , Mites as biological pest control agents , Pests -- Biological control , Biological pest control agents , Predation (Biology)
- Description: Dasineura sp. is a gall forming midge that was introduced into South Africa for the biocontrol of the Australian myrtle, Leptospermum laevigatum. It causes galls on both the vegetative and reproductive buds of the plant. Although Dasineura sp. was initially regarded as a potentially successful agent, galling up to 99 percent of the buds of the host plant, it has been preyed on by native opportunistic mites, which caused a decline in the performance of the midge as a biocontrol agent of L. laevigatum. This raised a concern about whether this fly will be able to perform effectively in the presence of its new natural enemies. Therefore, the objectives of this study were to: 1) ascertain whether mite abundance has seasonal variations; 2) determine if plant density and plant size have an effect on midge predation by the mites; and 3) determine if midge predation varies in different locations. The study was conducted at three sites in the Hermanus area, Western Cape Province. Every three weeks for thirteen months, galls were collected and dissected so as to count and record the numbers of midge larvae, pupae, adults and mites that were found. Data collected showed that predation varied with season, and the mites were scarce during the flowering season. Predation also varied among the study sites and plant density had an effect on midge predation. Midges in smaller plants (saplings) were more vulnerable to predation than those in the bigger plants (plants from isolates and thickets). It was concluded that although mites have an effect on midge populations, they do not prevent their establishment on the plant. Therefore, a survey should be done in two to three years time to check if the midges are still persisting on the plant, vi and recommendations are that a new agent should be released to supplement the midges.
- Full Text:
- Date Issued: 2010
- Authors: Mdlangu, Thabisa Lynette Honey
- Date: 2010
- Subjects: Dasyneura leguminicola , Myrtaceae -- South Africa , Mites as biological pest control agents , Pests -- Biological control , Biological pest control agents , Predation (Biology)
- Language: English
- Type: Thesis , Masters , MSc (Zoology)
- Identifier: vital:11789 , http://hdl.handle.net/10353/272 , Dasyneura leguminicola , Myrtaceae -- South Africa , Mites as biological pest control agents , Pests -- Biological control , Biological pest control agents , Predation (Biology)
- Description: Dasineura sp. is a gall forming midge that was introduced into South Africa for the biocontrol of the Australian myrtle, Leptospermum laevigatum. It causes galls on both the vegetative and reproductive buds of the plant. Although Dasineura sp. was initially regarded as a potentially successful agent, galling up to 99 percent of the buds of the host plant, it has been preyed on by native opportunistic mites, which caused a decline in the performance of the midge as a biocontrol agent of L. laevigatum. This raised a concern about whether this fly will be able to perform effectively in the presence of its new natural enemies. Therefore, the objectives of this study were to: 1) ascertain whether mite abundance has seasonal variations; 2) determine if plant density and plant size have an effect on midge predation by the mites; and 3) determine if midge predation varies in different locations. The study was conducted at three sites in the Hermanus area, Western Cape Province. Every three weeks for thirteen months, galls were collected and dissected so as to count and record the numbers of midge larvae, pupae, adults and mites that were found. Data collected showed that predation varied with season, and the mites were scarce during the flowering season. Predation also varied among the study sites and plant density had an effect on midge predation. Midges in smaller plants (saplings) were more vulnerable to predation than those in the bigger plants (plants from isolates and thickets). It was concluded that although mites have an effect on midge populations, they do not prevent their establishment on the plant. Therefore, a survey should be done in two to three years time to check if the midges are still persisting on the plant, vi and recommendations are that a new agent should be released to supplement the midges.
- Full Text:
- Date Issued: 2010
Informing an ICT intervention for HIV and AIDS education at Rhodes University
- Authors: Gunzo, Fortunate Takawira
- Date: 2010
- Subjects: AIDS (Disease) -- Prevention -- South Africa AIDS (Disease) -- Study and teaching -- South Africa HIV infections -- Prevention -- South Africa HIV infections -- Study and teaching -- South Africa Health education -- South Africa Educational technology -- South Africa Rhodes University -- Students -- Attitudes Counseling in higher education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1577 , http://hdl.handle.net/10962/d1003459
- Description: This study captures the process and methods used in selecting and organising content for an ontology. In the Information and Communication Technology (ICT) field ontology refers to a way of organising and storing information and facilitating interaction between the system and its users. Ontologies are being used more frequently to provide services that deal with complex information. In this study, I record my experience of developing content for an HIV and AIDS ontology for Rhodes University students. Using several different methods, I started the process of selecting and organising HIV and AIDS information, free of scientific jargon and prescriptive language, and consisting only of relevant information. I used data derived from interviews with six HIV and AIDS experts to develop questions for a survey that was open to all Rhodes University students. The 689 people who responded to the survey indicated that they needed more information on testing, treatment and living with HIV. Responses also showed that students had a lot of information on HIV prevention and transmission. Four focus group discussions revealed that students were tired of repetitions of the „same‟ information on HIV and AIDS and wanted to know more about life after contracting HIV. Using this data, I propose some guidelines to populate HIV and AIDS ontology. Ontologies can be customized for particular groups of users, for example according to gender, race, year of study etc. Another advantage of the ontology is that it can be expanded or contracted depending on the scope of one‟s intervention.
- Full Text:
- Date Issued: 2010
- Authors: Gunzo, Fortunate Takawira
- Date: 2010
- Subjects: AIDS (Disease) -- Prevention -- South Africa AIDS (Disease) -- Study and teaching -- South Africa HIV infections -- Prevention -- South Africa HIV infections -- Study and teaching -- South Africa Health education -- South Africa Educational technology -- South Africa Rhodes University -- Students -- Attitudes Counseling in higher education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1577 , http://hdl.handle.net/10962/d1003459
- Description: This study captures the process and methods used in selecting and organising content for an ontology. In the Information and Communication Technology (ICT) field ontology refers to a way of organising and storing information and facilitating interaction between the system and its users. Ontologies are being used more frequently to provide services that deal with complex information. In this study, I record my experience of developing content for an HIV and AIDS ontology for Rhodes University students. Using several different methods, I started the process of selecting and organising HIV and AIDS information, free of scientific jargon and prescriptive language, and consisting only of relevant information. I used data derived from interviews with six HIV and AIDS experts to develop questions for a survey that was open to all Rhodes University students. The 689 people who responded to the survey indicated that they needed more information on testing, treatment and living with HIV. Responses also showed that students had a lot of information on HIV prevention and transmission. Four focus group discussions revealed that students were tired of repetitions of the „same‟ information on HIV and AIDS and wanted to know more about life after contracting HIV. Using this data, I propose some guidelines to populate HIV and AIDS ontology. Ontologies can be customized for particular groups of users, for example according to gender, race, year of study etc. Another advantage of the ontology is that it can be expanded or contracted depending on the scope of one‟s intervention.
- Full Text:
- Date Issued: 2010
Innovation in post production stage of print Newspaper
- Authors: Fayo, Sicelo Nathaniel
- Date: 2010
- Subjects: Newspaper publishing -- Technological innovations , Newspapers -- Circulation , Newspapers -- Marketing
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8614 , http://hdl.handle.net/10948/1544 , Newspaper publishing -- Technological innovations , Newspapers -- Circulation , Newspapers -- Marketing
- Description: Print newspapers in South Africa are the oldest formal mode of news and information dissemination but which has come under tremendous pressure with the advent and spread of technological innovation involving information communication infrastructure and processes, but specifically the internet. The main challenge facing print newspapers in terms of circulation growth of print and advertising revenue is speed to market. The internet has not only provided a new avenue for news and information dissemination but has the distinct advantage of tremendous speed to deliver news and information to readers. Meanwhile, print newspapers whose production is still almost entirely dependent on traditional structures, processes and physical mode of delivery are battling to stay afloat as the chase for readers' attention is gaining more ground on digital platforms. This new competition landscape has now cast focus fully on traditional print media‟s production processes competency levels as well as their suitability for the nature of competition posed by digital news platforms. The processes involved in the production of a print newspaper can be described as hybrid (Davis and Heineke. 2005: 220) in that they involve different types of processes at different stages to produce the final product. The focus of this study at Avusa Media (Port Elizabeth) was on the post production processes involving the printing and distribution of printed newspapers with the objective of gaining an understanding of the extent and impact of the information technology advancement in the post production phase of printed newspapers. v In pursuing the goal, the case study research followed a phenomenological paradigm involving exploratory and descriptive research processes as described by Yin (1994) in Collis and Hussey (2003: 69) and Clifford Geertz (1973) in Babbie and Mouton (2005: 272) The research found that the traditional business structure for printed newspapers is increasingly becoming unviable due to poverty of technological innovation in critical parts of the production value chain; namely post production processes that encompass printing and distribution of printed newspapers. The research established and revealed that while there are some technological innovations and advances in the print newspaper publishing industry value chain worldwide, they are not only severely limited and disjointed but are also seemingly moving apart rather than towards consolidation in terms of the speed to market need faced by print newspaper publishers.
- Full Text:
- Date Issued: 2010
- Authors: Fayo, Sicelo Nathaniel
- Date: 2010
- Subjects: Newspaper publishing -- Technological innovations , Newspapers -- Circulation , Newspapers -- Marketing
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8614 , http://hdl.handle.net/10948/1544 , Newspaper publishing -- Technological innovations , Newspapers -- Circulation , Newspapers -- Marketing
- Description: Print newspapers in South Africa are the oldest formal mode of news and information dissemination but which has come under tremendous pressure with the advent and spread of technological innovation involving information communication infrastructure and processes, but specifically the internet. The main challenge facing print newspapers in terms of circulation growth of print and advertising revenue is speed to market. The internet has not only provided a new avenue for news and information dissemination but has the distinct advantage of tremendous speed to deliver news and information to readers. Meanwhile, print newspapers whose production is still almost entirely dependent on traditional structures, processes and physical mode of delivery are battling to stay afloat as the chase for readers' attention is gaining more ground on digital platforms. This new competition landscape has now cast focus fully on traditional print media‟s production processes competency levels as well as their suitability for the nature of competition posed by digital news platforms. The processes involved in the production of a print newspaper can be described as hybrid (Davis and Heineke. 2005: 220) in that they involve different types of processes at different stages to produce the final product. The focus of this study at Avusa Media (Port Elizabeth) was on the post production processes involving the printing and distribution of printed newspapers with the objective of gaining an understanding of the extent and impact of the information technology advancement in the post production phase of printed newspapers. v In pursuing the goal, the case study research followed a phenomenological paradigm involving exploratory and descriptive research processes as described by Yin (1994) in Collis and Hussey (2003: 69) and Clifford Geertz (1973) in Babbie and Mouton (2005: 272) The research found that the traditional business structure for printed newspapers is increasingly becoming unviable due to poverty of technological innovation in critical parts of the production value chain; namely post production processes that encompass printing and distribution of printed newspapers. The research established and revealed that while there are some technological innovations and advances in the print newspaper publishing industry value chain worldwide, they are not only severely limited and disjointed but are also seemingly moving apart rather than towards consolidation in terms of the speed to market need faced by print newspaper publishers.
- Full Text:
- Date Issued: 2010
Integer optimisation for the selection of a fantasy league cricket team
- Authors: Brettenny, Warren James
- Date: 2010
- Subjects: Sports -- Research -- Methodology , Teamwork (Sports) , Cricket players
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10565 , http://hdl.handle.net/10948/1230 , Sports -- Research -- Methodology , Teamwork (Sports) , Cricket players
- Description: Sports fans often scrutinise the team selection strategies employed by their favourite team's coach or selection panel. Many of these fans believe that they can perform the selection process far better than those tasked with the responsibility. Fantasy leagues, provide a platform for fans to test their hand at this selection procedure. Twenty20 cricket is a new and exciting form of cricket and has become very popular in recent years. This research focuses on bringing these concepts together by proposing a binary integer program to determine a team selection strategy for fantasy league cricket. This is done in a Twenty20 setting. The approach used in this study focuses on evaluating the effectiveness of previously developed performance measures in a fantasy league setting. Adjustments to these measures are made and new measures are proposed. These measures are then used to select a fantasy league team using a prospective approach. This is done to provide fantasy league participants with a mathematical procedure for fantasy league team selection.
- Full Text:
- Date Issued: 2010
- Authors: Brettenny, Warren James
- Date: 2010
- Subjects: Sports -- Research -- Methodology , Teamwork (Sports) , Cricket players
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10565 , http://hdl.handle.net/10948/1230 , Sports -- Research -- Methodology , Teamwork (Sports) , Cricket players
- Description: Sports fans often scrutinise the team selection strategies employed by their favourite team's coach or selection panel. Many of these fans believe that they can perform the selection process far better than those tasked with the responsibility. Fantasy leagues, provide a platform for fans to test their hand at this selection procedure. Twenty20 cricket is a new and exciting form of cricket and has become very popular in recent years. This research focuses on bringing these concepts together by proposing a binary integer program to determine a team selection strategy for fantasy league cricket. This is done in a Twenty20 setting. The approach used in this study focuses on evaluating the effectiveness of previously developed performance measures in a fantasy league setting. Adjustments to these measures are made and new measures are proposed. These measures are then used to select a fantasy league team using a prospective approach. This is done to provide fantasy league participants with a mathematical procedure for fantasy league team selection.
- Full Text:
- Date Issued: 2010
Investigating factors that negatively influence lean implementation in the Eastern Cape automotive industry
- Authors: Camagu, Sibo
- Date: 2010
- Subjects: Lean manufacturing -- South Africa -- Eastern Cape , Production management -- South Africa -- Eastern Cape , Industrial efficiency , Automobile industry and trade
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8655 , http://hdl.handle.net/10948/1360 , Lean manufacturing -- South Africa -- Eastern Cape , Production management -- South Africa -- Eastern Cape , Industrial efficiency , Automobile industry and trade
- Description: In this intensely competitive environment of the global economy, the survival of even the most established manufacturers depends on their ability to continuously improve quality whilst reducing costs. The resulting productivity of producing more with less is the only key to market leadership and sustainable competitive advantage. Changing production methods from mass-production to Lean Manufacturing has become the essential practise for successful manufacturers (Rogers and Sim, 2009). The purpose of this study is to investigate what factors negate the adoption and implementation of Lean Manufacturing as a means to gain competitive advantage. The focus was on companies that have participated in the AIDC Tirisano cluster programme. The study investigated what effect Organisational Culture, Leadership Behaviours, Employee Involvement and Strategy Integration have on Lean Manufacturing adoption and implementation. This study applied the mixed methodologies of qualitative and quantitative approaches using methodological triangulation. A cross sectional analytical survey approach in a descriptive case study was undertaken. The findings from the questions and the interviews from the respondents who participated in the survey indicated that the practices in some companies enable the successful adoption and implementation of Lean Manufacturing whilst in some others the practices will negatively affect the adoption and implementation. The study concludes by stating that South African automotive component manufacturers are under immense pressure to improve quality and reduce costs. Initiatives like Lean Manufacturing should be undertaken in order to bring about these improvements. But this improvement comes about by changing the current way of doing things. Companies need to undertake a total approach when implementing Lean as part of the business strategy and this must be driven by management as leaders and a team culture that involves all employees needs to be present.
- Full Text:
- Date Issued: 2010
- Authors: Camagu, Sibo
- Date: 2010
- Subjects: Lean manufacturing -- South Africa -- Eastern Cape , Production management -- South Africa -- Eastern Cape , Industrial efficiency , Automobile industry and trade
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8655 , http://hdl.handle.net/10948/1360 , Lean manufacturing -- South Africa -- Eastern Cape , Production management -- South Africa -- Eastern Cape , Industrial efficiency , Automobile industry and trade
- Description: In this intensely competitive environment of the global economy, the survival of even the most established manufacturers depends on their ability to continuously improve quality whilst reducing costs. The resulting productivity of producing more with less is the only key to market leadership and sustainable competitive advantage. Changing production methods from mass-production to Lean Manufacturing has become the essential practise for successful manufacturers (Rogers and Sim, 2009). The purpose of this study is to investigate what factors negate the adoption and implementation of Lean Manufacturing as a means to gain competitive advantage. The focus was on companies that have participated in the AIDC Tirisano cluster programme. The study investigated what effect Organisational Culture, Leadership Behaviours, Employee Involvement and Strategy Integration have on Lean Manufacturing adoption and implementation. This study applied the mixed methodologies of qualitative and quantitative approaches using methodological triangulation. A cross sectional analytical survey approach in a descriptive case study was undertaken. The findings from the questions and the interviews from the respondents who participated in the survey indicated that the practices in some companies enable the successful adoption and implementation of Lean Manufacturing whilst in some others the practices will negatively affect the adoption and implementation. The study concludes by stating that South African automotive component manufacturers are under immense pressure to improve quality and reduce costs. Initiatives like Lean Manufacturing should be undertaken in order to bring about these improvements. But this improvement comes about by changing the current way of doing things. Companies need to undertake a total approach when implementing Lean as part of the business strategy and this must be driven by management as leaders and a team culture that involves all employees needs to be present.
- Full Text:
- Date Issued: 2010
Investigating the benefits of using selected lean techniques at a South African exhaust manufacturer-a case study
- Authors: Louw, Andre
- Date: 2010
- Subjects: Automobile supplies industry , Factories
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8617 , http://hdl.handle.net/10948/1518 , Automobile supplies industry , Factories
- Description: This study investigates the implementation of supermarket-based scheduling of parts at a South African exhaust manufacturing plant. The study firstly investigates the requirements the manufacturer had to contend with in ensuring a valuable contract was won. The nature of the contract is such that it warrants building of a new facility. The design of the facility and the manufacturing processes is of importance as some Lean techniques are employed during these early stages. The research takes the form of a case study and data is collected mainly through interviews with staff, but also from direct observations on the shop-floor. Interviews were conducted with: - key project leaders responsible for the original design and commissioning of the facility; - production managers and technical staff currently operating the plant; and - shop-floor personnel involved in daily production and logistics operations within the plant. The as-built facility and procedures are compared with literature found on the topic of Lean manufacturing. Various findings are recorded, both on conforming to and not conforming to typical Lean theory. Potential changes are suggested in the following areas: - a Pull strategy is proposed to coincide with the appointment of a so-called pacemaker station; - a pacemaker would need to be further supported by a production leveling strategy; - although quality delivered to the customer is reported as very high, potential improvements are still possible by introducing an "at source" approach to reduce rework; and - finally, a Total Productive Maintenance (TPM) program will serve to reduce downtime even further.
- Full Text:
- Date Issued: 2010
- Authors: Louw, Andre
- Date: 2010
- Subjects: Automobile supplies industry , Factories
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8617 , http://hdl.handle.net/10948/1518 , Automobile supplies industry , Factories
- Description: This study investigates the implementation of supermarket-based scheduling of parts at a South African exhaust manufacturing plant. The study firstly investigates the requirements the manufacturer had to contend with in ensuring a valuable contract was won. The nature of the contract is such that it warrants building of a new facility. The design of the facility and the manufacturing processes is of importance as some Lean techniques are employed during these early stages. The research takes the form of a case study and data is collected mainly through interviews with staff, but also from direct observations on the shop-floor. Interviews were conducted with: - key project leaders responsible for the original design and commissioning of the facility; - production managers and technical staff currently operating the plant; and - shop-floor personnel involved in daily production and logistics operations within the plant. The as-built facility and procedures are compared with literature found on the topic of Lean manufacturing. Various findings are recorded, both on conforming to and not conforming to typical Lean theory. Potential changes are suggested in the following areas: - a Pull strategy is proposed to coincide with the appointment of a so-called pacemaker station; - a pacemaker would need to be further supported by a production leveling strategy; - although quality delivered to the customer is reported as very high, potential improvements are still possible by introducing an "at source" approach to reduce rework; and - finally, a Total Productive Maintenance (TPM) program will serve to reduce downtime even further.
- Full Text:
- Date Issued: 2010
Investigating the effect of various film-forming polymers on the evaporation rate of a volatile component in a cosmetic formulation
- Authors: Barnard, Carla
- Date: 2010
- Subjects: Cosmetic delivery systems , Controlled release preparations , Cosmetics , Polymers , Drugs -- Controlled release
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10377 , http://hdl.handle.net/10948/1498 , Cosmetic delivery systems , Controlled release preparations , Cosmetics , Polymers , Drugs -- Controlled release
- Description: The topical application of many substances, including drugs, enzymes, moisturizers and fragrances, contributes largely to the cosmetic and pharmaceutical industries. These components are often volatile in nature and dissipate in a matter of hours. When considering the different types of slow release systems, an overwhelming variety of these systems is available. Each one of the systems is unique in a way, and is designed to perform a particular function, whether it facilitates the controlled release of an active into the body via the skin surface (transdermal delivery) or whether it reduces the rate of loss of an active from the skin surface to the surrounding environment. For the purpose of this study, a previously existing fixative formulation which is believed to reduce the rate of loss of an active component to the environment, through film formation on the skin surface, was investigated. Alternative ingredients or components were incorporated together with the original fixative formulation ingredients into an experimental design which investigates the effect of each group of the components present. 18 formulations with various concentrations of the components within the groups and specified upper and lower limits for each component were formulated. The fixative properties of the formulations were analysed through the incorporation of a fixed amount of a simple fragrance molecule, 4- methoxybenzaldehyde, into each formulation and evaporation studies were conducted in an environmental room at 28±1° C over a period of 5 hours followed by gas chromatography analysis and finally data analyses using statistical methods. The most efficient fixative formulation was established using regression analysis. The fragrance compound in this formulation was found to evaporate at a rate of 0.47 g/L per hour. The least efficient fixative formulation lead to the loss of 0.78 g/L of the fragrance component per hour. From the calculated fragrance concentrations, the rate constant for each individual fixative formulation could be calculated and response surface 8 modelling by backward regression was used in order to determine how each component contributes to the rate of loss of the fragrance compound. Since the sum of the original ingredient and its alternative was constant, each of the original ingredients was coupled directly to its alternative and no conclusion could be made about the contribution of individual components. By increasing the concentration of Hydroxypropylcellulose (HPC) 100K and its alternative HPC 140K, while keeping the effects of the other components constant, a decrease in the rate of fragrance loss was observed. The same conclusion could be made when increasing the concentrations of PEG-12 Dimethicone and its alternative cetyl dimethicone (decreases the evaporation rate). An interaction took place between HPC 100K and PEG-12 dimethicone and their alternatives. The negative effect was, however, not as strong as the combined positive effect on the rate of fragrance loss of the individual components HPC and PEG-12 dimethicone. Evidence suggested that the removal of the components polyvinylpyrrolidone and its alternative, polyurethane-32 (Baycusan® C1003), would improve the effectiveness of the fixative formulation in terms of its slow release properties. A confirmation experiment established that the exclusion of these components from the fixative formulation does improve the “slow release” properties thereof. A larger, more intricate design is required to investigate the effect of each one of the individual components and where the sum of the components (original and its alternative) is not constant.
- Full Text:
- Date Issued: 2010
- Authors: Barnard, Carla
- Date: 2010
- Subjects: Cosmetic delivery systems , Controlled release preparations , Cosmetics , Polymers , Drugs -- Controlled release
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10377 , http://hdl.handle.net/10948/1498 , Cosmetic delivery systems , Controlled release preparations , Cosmetics , Polymers , Drugs -- Controlled release
- Description: The topical application of many substances, including drugs, enzymes, moisturizers and fragrances, contributes largely to the cosmetic and pharmaceutical industries. These components are often volatile in nature and dissipate in a matter of hours. When considering the different types of slow release systems, an overwhelming variety of these systems is available. Each one of the systems is unique in a way, and is designed to perform a particular function, whether it facilitates the controlled release of an active into the body via the skin surface (transdermal delivery) or whether it reduces the rate of loss of an active from the skin surface to the surrounding environment. For the purpose of this study, a previously existing fixative formulation which is believed to reduce the rate of loss of an active component to the environment, through film formation on the skin surface, was investigated. Alternative ingredients or components were incorporated together with the original fixative formulation ingredients into an experimental design which investigates the effect of each group of the components present. 18 formulations with various concentrations of the components within the groups and specified upper and lower limits for each component were formulated. The fixative properties of the formulations were analysed through the incorporation of a fixed amount of a simple fragrance molecule, 4- methoxybenzaldehyde, into each formulation and evaporation studies were conducted in an environmental room at 28±1° C over a period of 5 hours followed by gas chromatography analysis and finally data analyses using statistical methods. The most efficient fixative formulation was established using regression analysis. The fragrance compound in this formulation was found to evaporate at a rate of 0.47 g/L per hour. The least efficient fixative formulation lead to the loss of 0.78 g/L of the fragrance component per hour. From the calculated fragrance concentrations, the rate constant for each individual fixative formulation could be calculated and response surface 8 modelling by backward regression was used in order to determine how each component contributes to the rate of loss of the fragrance compound. Since the sum of the original ingredient and its alternative was constant, each of the original ingredients was coupled directly to its alternative and no conclusion could be made about the contribution of individual components. By increasing the concentration of Hydroxypropylcellulose (HPC) 100K and its alternative HPC 140K, while keeping the effects of the other components constant, a decrease in the rate of fragrance loss was observed. The same conclusion could be made when increasing the concentrations of PEG-12 Dimethicone and its alternative cetyl dimethicone (decreases the evaporation rate). An interaction took place between HPC 100K and PEG-12 dimethicone and their alternatives. The negative effect was, however, not as strong as the combined positive effect on the rate of fragrance loss of the individual components HPC and PEG-12 dimethicone. Evidence suggested that the removal of the components polyvinylpyrrolidone and its alternative, polyurethane-32 (Baycusan® C1003), would improve the effectiveness of the fixative formulation in terms of its slow release properties. A confirmation experiment established that the exclusion of these components from the fixative formulation does improve the “slow release” properties thereof. A larger, more intricate design is required to investigate the effect of each one of the individual components and where the sum of the components (original and its alternative) is not constant.
- Full Text:
- Date Issued: 2010
Investigating the effects of form-focused activities on the Acquisition of articles and pronouns in English amongst Grade 11 Xhosa learners
- Authors: White, Emma Lindsey
- Date: 2010
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8362 , http://hdl.handle.net/10948/1317
- Description: The main purpose of this dissertation is to investigate if a teaching method called Focus on Form (FonF) in an English as a Second Language (ESL) class is effective in the acquisition of two grammatical forms namely articles ("a", "an" and "the") and a selection of pronouns. In order to test this hypothesis, quantitative research was performed. The analysis of a series of tests was done quantitatively to prove the hypothesis. The dissertation includes a theory section on Social Capital (SC) and discusses why it might play an important part in South Africa and in offering some help to the communities to enable them to help in the education of their children within South Africa. This dissertation is divided into five chapters. The first chapter introduces the problem and explains how South African education, historically, had devastating effects in the past and continues having a far reaching effect on today‟s learners. It discusses why this dissertation focuses on English and highlights how extensively English has spread throughout the world. It contains an explanation of the value of being competent in the English language. The chapter continues with a depiction of the poor pass rates of the end of year high school examinations, The National Senior Certificate (NSC). It explains the significance of the research, the purpose of the study, its theoretical framework and finally what this study proposes. Chapter two is a literature review of the available literature discussing second language acquisition (SLA) and the difference between English as a Foreign Language (EFL) and English as a Second Language (ESL). The chapter continues with a detailed description of how English was taught historically with an explanation of the approach being used in this study. Chapter two continues with details of the historical "Bantu Education Act No 47 of 1953" and the racist policies of the government of the time with an exploration of the effect these policies had on the education of learners. It also specifies the grammatical forms being used in this study. A summary of Black South African English (BSAE) is included accompanied by a description of language transfer. The chapter contains a section on SC, with an explanation of how this term came about historically and what it means. The chapter includes social problems that South Africa is facing today and how these problems tie in with diminished SC. It explains the importance of SC in Education. The chapter concludes with an explanation of how SC can be utilized in communities and why it is important in a democratic country. Chapter three explains the methodology used in this study as that of positivism and that this study in one sense is purely an empirical study and the reasons behind the choice of methodology. It also explains how a section of this study is pragmatic. Although the testing and analysis is purely statistical, the lessons that took place in the classroom, the interpersonal communication combined with the interaction between the learners and the researcher was not quantitative in nature. This interaction had no outright bearing on the results, but allowed the researcher the opportunity to observe and take notes on the experiences of the learners and the researcher in the classroom. These observations included incidents within the lessons and external problems the learners face which are linked to social issues within the literature. The chapter also contains an explanation of the testing instruments used in this study and how they were developed along with the ethical considerations of the study. Chapter four details the statistical results of this study. It also contains the write up of the field notes of the researcher who took note of incidents that happened within the classes. There are some examples of family and personal problems related to the learners and details the environment of the school. Some of these issues tie in with the theory included; illustrating the ideas and concerns associated with SC and demonstrates how these social problems are truly part of each learner‟s life in a township school. Chapter five offers recommendations to English teachers, the Department of Education (DoE) and to future researchers based on the results of Chapter four. It contains a discussion on how the community can increase SC within their own areas and within the schools. This study argues that the Education system is in dire need of help as evidenced by the dismal exam results. It also argues that South Africa has a variety of social problems that are contributing to the overall failure and dropout rate in schools. It offers some general suggestions on how the community can work together to build systems within the community, to help themselves and their children to become educated, productive members of society. The only way for the children of South Africa to succeed is with a good education as their starting point.
- Full Text:
- Date Issued: 2010
- Authors: White, Emma Lindsey
- Date: 2010
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8362 , http://hdl.handle.net/10948/1317
- Description: The main purpose of this dissertation is to investigate if a teaching method called Focus on Form (FonF) in an English as a Second Language (ESL) class is effective in the acquisition of two grammatical forms namely articles ("a", "an" and "the") and a selection of pronouns. In order to test this hypothesis, quantitative research was performed. The analysis of a series of tests was done quantitatively to prove the hypothesis. The dissertation includes a theory section on Social Capital (SC) and discusses why it might play an important part in South Africa and in offering some help to the communities to enable them to help in the education of their children within South Africa. This dissertation is divided into five chapters. The first chapter introduces the problem and explains how South African education, historically, had devastating effects in the past and continues having a far reaching effect on today‟s learners. It discusses why this dissertation focuses on English and highlights how extensively English has spread throughout the world. It contains an explanation of the value of being competent in the English language. The chapter continues with a depiction of the poor pass rates of the end of year high school examinations, The National Senior Certificate (NSC). It explains the significance of the research, the purpose of the study, its theoretical framework and finally what this study proposes. Chapter two is a literature review of the available literature discussing second language acquisition (SLA) and the difference between English as a Foreign Language (EFL) and English as a Second Language (ESL). The chapter continues with a detailed description of how English was taught historically with an explanation of the approach being used in this study. Chapter two continues with details of the historical "Bantu Education Act No 47 of 1953" and the racist policies of the government of the time with an exploration of the effect these policies had on the education of learners. It also specifies the grammatical forms being used in this study. A summary of Black South African English (BSAE) is included accompanied by a description of language transfer. The chapter contains a section on SC, with an explanation of how this term came about historically and what it means. The chapter includes social problems that South Africa is facing today and how these problems tie in with diminished SC. It explains the importance of SC in Education. The chapter concludes with an explanation of how SC can be utilized in communities and why it is important in a democratic country. Chapter three explains the methodology used in this study as that of positivism and that this study in one sense is purely an empirical study and the reasons behind the choice of methodology. It also explains how a section of this study is pragmatic. Although the testing and analysis is purely statistical, the lessons that took place in the classroom, the interpersonal communication combined with the interaction between the learners and the researcher was not quantitative in nature. This interaction had no outright bearing on the results, but allowed the researcher the opportunity to observe and take notes on the experiences of the learners and the researcher in the classroom. These observations included incidents within the lessons and external problems the learners face which are linked to social issues within the literature. The chapter also contains an explanation of the testing instruments used in this study and how they were developed along with the ethical considerations of the study. Chapter four details the statistical results of this study. It also contains the write up of the field notes of the researcher who took note of incidents that happened within the classes. There are some examples of family and personal problems related to the learners and details the environment of the school. Some of these issues tie in with the theory included; illustrating the ideas and concerns associated with SC and demonstrates how these social problems are truly part of each learner‟s life in a township school. Chapter five offers recommendations to English teachers, the Department of Education (DoE) and to future researchers based on the results of Chapter four. It contains a discussion on how the community can increase SC within their own areas and within the schools. This study argues that the Education system is in dire need of help as evidenced by the dismal exam results. It also argues that South Africa has a variety of social problems that are contributing to the overall failure and dropout rate in schools. It offers some general suggestions on how the community can work together to build systems within the community, to help themselves and their children to become educated, productive members of society. The only way for the children of South Africa to succeed is with a good education as their starting point.
- Full Text:
- Date Issued: 2010
Investigation and development of an e judiciary service for a citizen oriented judiciary system for rural communities
- Authors: Scott, Mfundo Shakes
- Date: 2010
- Subjects: Digital divide -- South Africa -- Eastern Cape , Rural development projects -- South Africa -- Eastern Cape , Community development -- South Africa -- Eastern Cape , User interfaces (Computer systems)
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11390 , http://hdl.handle.net/10353/275 , Digital divide -- South Africa -- Eastern Cape , Rural development projects -- South Africa -- Eastern Cape , Community development -- South Africa -- Eastern Cape , User interfaces (Computer systems)
- Description: One of the factors that contribute towards slow rural development is the presence of the digital divide. An area where the digital divide is still prevalent is the administration of justice within traditional contexts. One of the areas affected by this problem is the Dwesa rural community, situated on the Wild Coast of the former homeland of Transkei, in the Eastern Cape Province of South Africa. To address this problem for the Dwesa community, a research project on developing and implementing an e-Judiciary service was undertaken. The primary objective of this project was to develop a web application to support traditional justice administration in the Dwesa community. Due to the lack of a proper legal environment in this community, the e-Judiciary service acts as a portal for safe-keeping of judicial information. Such a system also serves as a platform for the administration of minor offences that are solved by the traditional courts. Furthermore, it provides a better working environment for traditional judicial leaders and eliminates the difficulty of accessing legal information by the rest of the community. Through the availability and use of the service, community members are provided with understanding and knowledge about judiciary operations and services in their community.
- Full Text:
- Date Issued: 2010
- Authors: Scott, Mfundo Shakes
- Date: 2010
- Subjects: Digital divide -- South Africa -- Eastern Cape , Rural development projects -- South Africa -- Eastern Cape , Community development -- South Africa -- Eastern Cape , User interfaces (Computer systems)
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11390 , http://hdl.handle.net/10353/275 , Digital divide -- South Africa -- Eastern Cape , Rural development projects -- South Africa -- Eastern Cape , Community development -- South Africa -- Eastern Cape , User interfaces (Computer systems)
- Description: One of the factors that contribute towards slow rural development is the presence of the digital divide. An area where the digital divide is still prevalent is the administration of justice within traditional contexts. One of the areas affected by this problem is the Dwesa rural community, situated on the Wild Coast of the former homeland of Transkei, in the Eastern Cape Province of South Africa. To address this problem for the Dwesa community, a research project on developing and implementing an e-Judiciary service was undertaken. The primary objective of this project was to develop a web application to support traditional justice administration in the Dwesa community. Due to the lack of a proper legal environment in this community, the e-Judiciary service acts as a portal for safe-keeping of judicial information. Such a system also serves as a platform for the administration of minor offences that are solved by the traditional courts. Furthermore, it provides a better working environment for traditional judicial leaders and eliminates the difficulty of accessing legal information by the rest of the community. Through the availability and use of the service, community members are provided with understanding and knowledge about judiciary operations and services in their community.
- Full Text:
- Date Issued: 2010
Investigation of entomopathogenic fungi for control of false codling moth, Thaumatotibia leucotrata, Mediterranean fruit fly, Ceratitis capitata and Natal fruit fly, C. rosa in South African citrus
- Authors: Goble, Tarryn Anne
- Date: 2010
- Subjects: Insect pests -- Biological control , Tortricidae -- Biological control -- South Africa , Tephritidae -- Biological control -- South Africa , Citrus -- Diseases and pests -- Biological control -- South Africa , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5723 , http://hdl.handle.net/10962/d1005409 , Insect pests -- Biological control , Tortricidae -- Biological control -- South Africa , Tephritidae -- Biological control -- South Africa , Citrus -- Diseases and pests -- Biological control -- South Africa , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
- Description: The biology of key citrus pests Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae), Ceratitis capitata Wiedemann (Diptera: Tephritidae) and Ceratitis rosa Karsch (Diptera: Tephritidae) includes their dropping from host plants to pupate in the soil below citrus trees. Since most EP fungi are soil-borne microorganisms, the development and formulation of alternative control strategies using these fungi as subterranean control agents, targeted at larvae and pupae in the soil, can potentially benefit existing IPM management of citrus in South Africa. Thus, a survey of occurrence of entomopathogenic fungi was undertaken on soils from citrus orchards and natural vegetation (refugia) on conventionally and organically managed farms in the Eastern Cape Province in South Africa. A method for baiting soil samples with citrus pest T. leucotreta and C. capitata larvae, as well as with the standard bait insect, Galleria mellonella Linnaeus (Lepidoptera: Pyralidae), was implemented. Sixty-two potentially useful entomopathogenic fungal isolates belonging to four genera were collected from 288 soil samples, an occurrence frequency of 21.53%. The most frequently isolated entomopathogenic fungal species was Beauveria bassiana (Balsamo) Vuillemin (15.63%), followed by Metarhizium anisopliae var. anisopliae (Metschnikoff) Sorokin (3.82%). Galleria mellonella was the most effective insect used to isolate fungal species (χ2=40.13, df=2, P≤ 0.005), with a total of 45 isolates obtained, followed by C. capitata with 11 isolates, and T. leucotreta with six isolates recovered. There was a significantly (χ2=11.65, df=1, P≤ 0.005) higher occurrence of entomopathogenic fungi in soil samples taken from refugia compared to cultivated orchards of both organically and conventionally managed farms. No significant differences were observed in the recovery of fungal isolates when soil samples from both farming systems were compared. The physiological effects and host range of 21 indigenous fungal isolates obtained in the Eastern Cape were investigated in the laboratory to establish whether these isolates could be effectively used as biological control agents against the subterranean life stages of C. rosa, C. capitata and T. leucotreta. When these pests were treated with a fungal concentration of 1 x 10⁷ conidia ml⁻¹, the percentage of T. leucotreta adults which emerged in fungal treated sand ranged from 5 to 60% (F=33.295; df=21; P=0.0001) depending on fungal isolate and the percentage of pupae with visible signs of mycosis ranged from 21 to 93% (F= 96.436; df=21; P=0.0001). Based on fungal isolates, the percentage adult survival in C. rosa and C. capitata ranged from 30 to 90% and 55 to 86% respectively. The percentage of C. rosa and C. capitata puparia with visible signs of mycosis ranged from 1 to 14% and 1 to 11% respectively. Deferred mortality due to mycosis in C. rosa and C. capitata adult flies ranged from 1 to 58% and 1 to 33% respectively, depending on fungal isolate. Entomopathogenic fungal isolates had a significantly greater effect on the adults of C. rosa and C. capitata than they did on the puparia of these two fruit fly species. Further, C. rosa and C. capitata did not differ significantly in their response to entomopathogenic fungi when adult survival or adult and pupal mycosis were considered. The relative potency of the four most virulent Beauveria isolates as well as the commercially available Beauveria bassiana product, Bb Plus® (Biological Control Products, South Africa), were compared against one another as log-probit regressions of mortality against C. rosa, C. capitata and T. leucotreta which all exhibited a dose-dependent response. Against fruit flies the estimated LC50 values of all five Beauveria isolates ranged from 5.5 x 10¹¹ to 2.8 x 10¹² conidia/ml⁻¹. There were no significant differences between the relative potencies of these five fungal isolates. When T. leucotreta was considered, isolates: G Moss R10 and G 14 2 B5 and Bb Plus® were significantly more pathogenic than G B Ar 23 B3 and FCM 10 13 L1. The estimated LC₅₀ values of the three most pathogenic isolates ranged from 6.8 x 10⁵ to 2.1 x 10⁶ conidia/ml⁻¹, while those of the least pathogenic ranged from 1.6 x 10⁷ to 3.7 x 10⁷ conidia/ml⁻¹. Thaumatotibia leucotreta final instar larvae were exposed to two conidial concentrations, at four different exposure times (12, 48, 72 and 96 hrs) and showed an exposure time-dependant relationship (F=5.43; df=3; P=0.001). At 1 x 10⁷conidia/ml⁻¹ two Beauveria isolates: G Moss R10 and G 14 2 B5 were able to elicit a response in 50% of test insects at 72 hrs (3 days) exposure. Although a limited amount of mycosis was observed in the puparia of both fruit fly species, deferred adult mortality due to mycosis was high. The increased incidence of adult mortality suggests that post emergence mycosis in adult fruit flies may play a more significant role in field suppression than the control of fruit flies at the pupal stage. The increased incidence of pupal mortality, as well as the relatively low concentrations of conidia required to elicit meaningful responses in T. leucotreta pupae may suggest that pre-emergent control of false codling moth will play a more significant role in field suppression than the control of adult life stages using indigenous isolates of entomopathogenic fungi. Various entomopathogenic fungal application techniques targeted at key insect pests within integrated pest management (IPM) systems of citrus are discussed.
- Full Text:
- Date Issued: 2010
- Authors: Goble, Tarryn Anne
- Date: 2010
- Subjects: Insect pests -- Biological control , Tortricidae -- Biological control -- South Africa , Tephritidae -- Biological control -- South Africa , Citrus -- Diseases and pests -- Biological control -- South Africa , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5723 , http://hdl.handle.net/10962/d1005409 , Insect pests -- Biological control , Tortricidae -- Biological control -- South Africa , Tephritidae -- Biological control -- South Africa , Citrus -- Diseases and pests -- Biological control -- South Africa , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
- Description: The biology of key citrus pests Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae), Ceratitis capitata Wiedemann (Diptera: Tephritidae) and Ceratitis rosa Karsch (Diptera: Tephritidae) includes their dropping from host plants to pupate in the soil below citrus trees. Since most EP fungi are soil-borne microorganisms, the development and formulation of alternative control strategies using these fungi as subterranean control agents, targeted at larvae and pupae in the soil, can potentially benefit existing IPM management of citrus in South Africa. Thus, a survey of occurrence of entomopathogenic fungi was undertaken on soils from citrus orchards and natural vegetation (refugia) on conventionally and organically managed farms in the Eastern Cape Province in South Africa. A method for baiting soil samples with citrus pest T. leucotreta and C. capitata larvae, as well as with the standard bait insect, Galleria mellonella Linnaeus (Lepidoptera: Pyralidae), was implemented. Sixty-two potentially useful entomopathogenic fungal isolates belonging to four genera were collected from 288 soil samples, an occurrence frequency of 21.53%. The most frequently isolated entomopathogenic fungal species was Beauveria bassiana (Balsamo) Vuillemin (15.63%), followed by Metarhizium anisopliae var. anisopliae (Metschnikoff) Sorokin (3.82%). Galleria mellonella was the most effective insect used to isolate fungal species (χ2=40.13, df=2, P≤ 0.005), with a total of 45 isolates obtained, followed by C. capitata with 11 isolates, and T. leucotreta with six isolates recovered. There was a significantly (χ2=11.65, df=1, P≤ 0.005) higher occurrence of entomopathogenic fungi in soil samples taken from refugia compared to cultivated orchards of both organically and conventionally managed farms. No significant differences were observed in the recovery of fungal isolates when soil samples from both farming systems were compared. The physiological effects and host range of 21 indigenous fungal isolates obtained in the Eastern Cape were investigated in the laboratory to establish whether these isolates could be effectively used as biological control agents against the subterranean life stages of C. rosa, C. capitata and T. leucotreta. When these pests were treated with a fungal concentration of 1 x 10⁷ conidia ml⁻¹, the percentage of T. leucotreta adults which emerged in fungal treated sand ranged from 5 to 60% (F=33.295; df=21; P=0.0001) depending on fungal isolate and the percentage of pupae with visible signs of mycosis ranged from 21 to 93% (F= 96.436; df=21; P=0.0001). Based on fungal isolates, the percentage adult survival in C. rosa and C. capitata ranged from 30 to 90% and 55 to 86% respectively. The percentage of C. rosa and C. capitata puparia with visible signs of mycosis ranged from 1 to 14% and 1 to 11% respectively. Deferred mortality due to mycosis in C. rosa and C. capitata adult flies ranged from 1 to 58% and 1 to 33% respectively, depending on fungal isolate. Entomopathogenic fungal isolates had a significantly greater effect on the adults of C. rosa and C. capitata than they did on the puparia of these two fruit fly species. Further, C. rosa and C. capitata did not differ significantly in their response to entomopathogenic fungi when adult survival or adult and pupal mycosis were considered. The relative potency of the four most virulent Beauveria isolates as well as the commercially available Beauveria bassiana product, Bb Plus® (Biological Control Products, South Africa), were compared against one another as log-probit regressions of mortality against C. rosa, C. capitata and T. leucotreta which all exhibited a dose-dependent response. Against fruit flies the estimated LC50 values of all five Beauveria isolates ranged from 5.5 x 10¹¹ to 2.8 x 10¹² conidia/ml⁻¹. There were no significant differences between the relative potencies of these five fungal isolates. When T. leucotreta was considered, isolates: G Moss R10 and G 14 2 B5 and Bb Plus® were significantly more pathogenic than G B Ar 23 B3 and FCM 10 13 L1. The estimated LC₅₀ values of the three most pathogenic isolates ranged from 6.8 x 10⁵ to 2.1 x 10⁶ conidia/ml⁻¹, while those of the least pathogenic ranged from 1.6 x 10⁷ to 3.7 x 10⁷ conidia/ml⁻¹. Thaumatotibia leucotreta final instar larvae were exposed to two conidial concentrations, at four different exposure times (12, 48, 72 and 96 hrs) and showed an exposure time-dependant relationship (F=5.43; df=3; P=0.001). At 1 x 10⁷conidia/ml⁻¹ two Beauveria isolates: G Moss R10 and G 14 2 B5 were able to elicit a response in 50% of test insects at 72 hrs (3 days) exposure. Although a limited amount of mycosis was observed in the puparia of both fruit fly species, deferred adult mortality due to mycosis was high. The increased incidence of adult mortality suggests that post emergence mycosis in adult fruit flies may play a more significant role in field suppression than the control of fruit flies at the pupal stage. The increased incidence of pupal mortality, as well as the relatively low concentrations of conidia required to elicit meaningful responses in T. leucotreta pupae may suggest that pre-emergent control of false codling moth will play a more significant role in field suppression than the control of adult life stages using indigenous isolates of entomopathogenic fungi. Various entomopathogenic fungal application techniques targeted at key insect pests within integrated pest management (IPM) systems of citrus are discussed.
- Full Text:
- Date Issued: 2010
Isolation of xylanolytic multi-enzyme complexes from Bacillus subtilis SJ01
- Authors: Jones, Sarah Melissa Jane
- Date: 2010
- Subjects: Bacillus subtilis , Xylans , Multienzyme complexes , Botanical chemistry , Cellulose , Hemicellulose , Polysaccharides
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3974 , http://hdl.handle.net/10962/d1004033 , Bacillus subtilis , Xylans , Multienzyme complexes , Botanical chemistry , Cellulose , Hemicellulose , Polysaccharides
- Description: Cellulose and hemicellulose account for a large portion of the world‘s plant biomass. In nature, these polysaccharides are intertwined forming complex materials that require multiple enzymes to degrade them. Multi-enzyme complexes (MECs) consist of a number of enzymes working in close proximity and synergistically to degrade complex substrates with higher efficiency than individual enzymes. The cellulosome is a cellulolytic MEC produced by anaerobic bacteria that has been studied extensively since its discovery in 1983. The aim of this study was to purify a cellulolytic and/or hemicellulolytic MEC from an aerobic bacterium of the Bacillus genus. Several bacterial isolates were identified using morphological characteristics and 16S rDNA sequencing, and screened for their ability to degrade cellulose and xylan using a MEC. The isolate that produced a high molecular weight protein fraction with the greatest ability to degrade Avicel®, carboxymethyl cellulose (CMC) and birchwood xylan was identified as Bacillus subtilis SJ01. An optimised growth medium, consisting of vitamins, trace elements, birchwood xylan (as the carbon source), and yeast and ammonium sulphate (as the nitrogen sources), increased the production of CMCase and xylanase enzymes from this bacterium. The removal of a competing bacterial strain from the culture and the inhibition of proteases also increased enzyme activities. A growth curve of B. subtilis SJ01 indicated that xylanase production was highest in early stationary growth phase and thus 84 hours was chosen as the best cell harvesting time. To purify the MECs produced by B. subtilis SJ01 size-exclusion chromatography on a Sephacryl S-400 column was used. It was concluded that (for the purposes of this study) the best method of concentrating the culture supernatant prior to loading onto Sephacryl S-400 was the use of ultrafiltration with a 50 kDa cut-off membrane. Two MECs, named C1 and C2 of 371 and 267 kDa, respectively, were purified from the culture supernatant of B. subtilis SJ01. Electrophoretic analysis revealed that these MECs consisted of 16 and 18 subunits, respectively, 4 of which degraded birchwood xylan and 5 of which degraded oat spelt xylan. The MECs degraded xylan substrates (C1: 0.24 U/mg, C2: 0.14 U/mg birchwood xylan) with higher efficiency than cellulose substrates (C1: 0.002 U/mg, C2: 0.01 U/mg CMC), and could therefore be considered xylanosomes. Interestingly, the MECs did not bind to insoluble birchwood xylan or Avicel® and did not contain glycosylated proteins, which are common features of cellulosomes. This study is, therefore, important in revealing the presence of MECs that differ from the cellulosome and that may have particular application in industries requiring high xylanase activity, such as the paper and pulp industry. The abundant genetic information available on B. subtilis means that this organism could also be used for genetic engineering of cellulolytic/hemicellulolytic MECs.
- Full Text:
- Date Issued: 2010
- Authors: Jones, Sarah Melissa Jane
- Date: 2010
- Subjects: Bacillus subtilis , Xylans , Multienzyme complexes , Botanical chemistry , Cellulose , Hemicellulose , Polysaccharides
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3974 , http://hdl.handle.net/10962/d1004033 , Bacillus subtilis , Xylans , Multienzyme complexes , Botanical chemistry , Cellulose , Hemicellulose , Polysaccharides
- Description: Cellulose and hemicellulose account for a large portion of the world‘s plant biomass. In nature, these polysaccharides are intertwined forming complex materials that require multiple enzymes to degrade them. Multi-enzyme complexes (MECs) consist of a number of enzymes working in close proximity and synergistically to degrade complex substrates with higher efficiency than individual enzymes. The cellulosome is a cellulolytic MEC produced by anaerobic bacteria that has been studied extensively since its discovery in 1983. The aim of this study was to purify a cellulolytic and/or hemicellulolytic MEC from an aerobic bacterium of the Bacillus genus. Several bacterial isolates were identified using morphological characteristics and 16S rDNA sequencing, and screened for their ability to degrade cellulose and xylan using a MEC. The isolate that produced a high molecular weight protein fraction with the greatest ability to degrade Avicel®, carboxymethyl cellulose (CMC) and birchwood xylan was identified as Bacillus subtilis SJ01. An optimised growth medium, consisting of vitamins, trace elements, birchwood xylan (as the carbon source), and yeast and ammonium sulphate (as the nitrogen sources), increased the production of CMCase and xylanase enzymes from this bacterium. The removal of a competing bacterial strain from the culture and the inhibition of proteases also increased enzyme activities. A growth curve of B. subtilis SJ01 indicated that xylanase production was highest in early stationary growth phase and thus 84 hours was chosen as the best cell harvesting time. To purify the MECs produced by B. subtilis SJ01 size-exclusion chromatography on a Sephacryl S-400 column was used. It was concluded that (for the purposes of this study) the best method of concentrating the culture supernatant prior to loading onto Sephacryl S-400 was the use of ultrafiltration with a 50 kDa cut-off membrane. Two MECs, named C1 and C2 of 371 and 267 kDa, respectively, were purified from the culture supernatant of B. subtilis SJ01. Electrophoretic analysis revealed that these MECs consisted of 16 and 18 subunits, respectively, 4 of which degraded birchwood xylan and 5 of which degraded oat spelt xylan. The MECs degraded xylan substrates (C1: 0.24 U/mg, C2: 0.14 U/mg birchwood xylan) with higher efficiency than cellulose substrates (C1: 0.002 U/mg, C2: 0.01 U/mg CMC), and could therefore be considered xylanosomes. Interestingly, the MECs did not bind to insoluble birchwood xylan or Avicel® and did not contain glycosylated proteins, which are common features of cellulosomes. This study is, therefore, important in revealing the presence of MECs that differ from the cellulosome and that may have particular application in industries requiring high xylanase activity, such as the paper and pulp industry. The abundant genetic information available on B. subtilis means that this organism could also be used for genetic engineering of cellulolytic/hemicellulolytic MECs.
- Full Text:
- Date Issued: 2010
Israel and Palestine: some critical international relations perspectives on the 'two-state' solution
- Authors: Pienaar, Ashwin Mark
- Date: 2010
- Subjects: Arab-Israeli conflict Jewish-Arab relations Nationalism -- Israel Nationalism -- Palestine Land settlement -- West Bank Land settlement -- Gaza Strip Realism Liberalism Palestinian Arabs -- Politics and government -- 20th century Israel -- Politics and government -- 20th century Israel -- Foreign relations -- Palestine Palestine -- Foreign relations -- Israel
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2820 , http://hdl.handle.net/10962/d1003030
- Description: This research questions whether Israel and Palestine should be divided into two states. Viewed through the International Relations (IR) theories of Realism and Liberalism, the ‘Two-State’ solution is the orthodox policy for Israel and Palestine. But Israelis and Palestinians are interspersed and share many of the same resources making it difficult to create two states. So, this research critiques the aforementioned IR theories which underpin the ‘Two-State’ solution. The conclusion reached is that there ought to be new thinking on how to resolve the Israel-Palestine issue.
- Full Text:
- Date Issued: 2010
Israel and Palestine: some critical international relations perspectives on the 'two-state' solution
- Authors: Pienaar, Ashwin Mark
- Date: 2010
- Subjects: Arab-Israeli conflict Jewish-Arab relations Nationalism -- Israel Nationalism -- Palestine Land settlement -- West Bank Land settlement -- Gaza Strip Realism Liberalism Palestinian Arabs -- Politics and government -- 20th century Israel -- Politics and government -- 20th century Israel -- Foreign relations -- Palestine Palestine -- Foreign relations -- Israel
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2820 , http://hdl.handle.net/10962/d1003030
- Description: This research questions whether Israel and Palestine should be divided into two states. Viewed through the International Relations (IR) theories of Realism and Liberalism, the ‘Two-State’ solution is the orthodox policy for Israel and Palestine. But Israelis and Palestinians are interspersed and share many of the same resources making it difficult to create two states. So, this research critiques the aforementioned IR theories which underpin the ‘Two-State’ solution. The conclusion reached is that there ought to be new thinking on how to resolve the Israel-Palestine issue.
- Full Text:
- Date Issued: 2010
Language policy and practice at CM Vellem and PJ Olivier primary schools
- Authors: Fobe, Mila Pamella
- Date: 2010
- Subjects: C M Vellem School P J Olivier School Public schools -- South Africa -- Grahamstown Language policy -- South Africa Language and education -- South Africa -- Grahamstown Native language and education -- South Africa -- Grahamstown Afrikaans language -- Study and teaching (Primary) -- South Africa -- Grahamstown Xhosa language -- Study and teaching (Primary) -- South Africa -- Grahamstown English language -- Study and teaching (Primary) -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3586 , http://hdl.handle.net/10962/d1002161
- Description: This study looks at language policy and practice at two Eastern Cape schools. It further explores the link between language learning and teaching. Language implementation strategies were the main focus of this study. The Language-in-education policy of the Republic of South Africa (1997) promotes the use of all nine African languages, which have been afforded the status of official languages. This study looks at the language teaching practices at two Grahamstown primary schools, where isiXhosa and Afrikaans have been used as media of instruction. Qualitative methods were used, and the study took the form of interpretive case studies. , Thuto e, e ikaelela go tshegetsa patlisiso e e ka ga gore dipuo tsa Selegae tsa Seaforika mo Aforikaborwa di tshwanelwa ke go tsewa ka maemo le mokgwa o o lekanang go ya ka Molaotheo wa Aforikaborwa. Ka jalo, e tlaa utolola,e ribilole ditsela le go batla malepa a puso ya Aforikaborwa e ka fitlhelelang setšhaba se se kwa magaeng, se bokgoni jwa kitso ya Seesimane bo leng kwa tlase mo go bona. Bothata ke gore Aforikaborwa e laolwa bogolo ke tiriso e e kwa godimo ya Seesimane mme puso e tshwanelwa ke gore e tlose dikgoreletsi tse di leng teng ga jaana tsa puo. E bowe gape e thibele go se lekalekaneng ga botshelo ka kakaretso mo loagong go go tlholwang ke go sa lekalekaneng ga kitso ya dipuo mo setšhabeng ka kakaretso. Ditshwanelo mo puong fela jaaka ditshwanelo dingwe le dingwe tsa botho, di tshwanelwa ke go sireletswa, jaaka di akareditswe mo Molaotheo o mošwa wa temokerasi wa Aforikaborwa.
- Full Text:
- Date Issued: 2010
- Authors: Fobe, Mila Pamella
- Date: 2010
- Subjects: C M Vellem School P J Olivier School Public schools -- South Africa -- Grahamstown Language policy -- South Africa Language and education -- South Africa -- Grahamstown Native language and education -- South Africa -- Grahamstown Afrikaans language -- Study and teaching (Primary) -- South Africa -- Grahamstown Xhosa language -- Study and teaching (Primary) -- South Africa -- Grahamstown English language -- Study and teaching (Primary) -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3586 , http://hdl.handle.net/10962/d1002161
- Description: This study looks at language policy and practice at two Eastern Cape schools. It further explores the link between language learning and teaching. Language implementation strategies were the main focus of this study. The Language-in-education policy of the Republic of South Africa (1997) promotes the use of all nine African languages, which have been afforded the status of official languages. This study looks at the language teaching practices at two Grahamstown primary schools, where isiXhosa and Afrikaans have been used as media of instruction. Qualitative methods were used, and the study took the form of interpretive case studies. , Thuto e, e ikaelela go tshegetsa patlisiso e e ka ga gore dipuo tsa Selegae tsa Seaforika mo Aforikaborwa di tshwanelwa ke go tsewa ka maemo le mokgwa o o lekanang go ya ka Molaotheo wa Aforikaborwa. Ka jalo, e tlaa utolola,e ribilole ditsela le go batla malepa a puso ya Aforikaborwa e ka fitlhelelang setšhaba se se kwa magaeng, se bokgoni jwa kitso ya Seesimane bo leng kwa tlase mo go bona. Bothata ke gore Aforikaborwa e laolwa bogolo ke tiriso e e kwa godimo ya Seesimane mme puso e tshwanelwa ke gore e tlose dikgoreletsi tse di leng teng ga jaana tsa puo. E bowe gape e thibele go se lekalekaneng ga botshelo ka kakaretso mo loagong go go tlholwang ke go sa lekalekaneng ga kitso ya dipuo mo setšhabeng ka kakaretso. Ditshwanelo mo puong fela jaaka ditshwanelo dingwe le dingwe tsa botho, di tshwanelwa ke go sireletswa, jaaka di akareditswe mo Molaotheo o mošwa wa temokerasi wa Aforikaborwa.
- Full Text:
- Date Issued: 2010
Laser surface hardening of AISI 1518 alloy steel
- Authors: Zhang, Tao
- Date: 2010
- Subjects: Lasers , Laser beams , Lasers in engineering , Nd-YAG lasers , Steel alloys , Surfaces -- Effect of radiation on
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9613 , http://hdl.handle.net/10948/723 , Lasers , Laser beams , Lasers in engineering , Nd-YAG lasers , Steel alloys , Surfaces -- Effect of radiation on
- Description: The laser surface hardening process will enhance the hardness profile of automotive components and ensure better process control and predictability of quality as compared to the conventional hardening processes. A 2KW Nd-YAG laser system was used to harden the surface of alloy steel with various process parameters (laser power, focal spot diameter and beam velocity). The results (microhardness, microstructure change and residual stress distribution) were measured and analyzed with Vickers microhardness tester, optical/electron microscope and hole-drilling residual stress equipment. Statistical analyses of the experimental data were used for explaining the relationships between process parameters, microhardness and microstructure. General thermal hardening was applied in the research to show the influence of heating temperature and cooling method on microstructure and mechanical properties. Also, the results were compared with laser surface hardening process from microhardness, microstructure and residual stress to show the advantage of laser surface hardening. Through analysis of the results of the laser surface hardening experiments, a suitable laser power density and interaction time for optimum hardening was obtained. The presented laser surface hardening process can also be applied to other alloy steel surface hardening process.
- Full Text:
- Date Issued: 2010
- Authors: Zhang, Tao
- Date: 2010
- Subjects: Lasers , Laser beams , Lasers in engineering , Nd-YAG lasers , Steel alloys , Surfaces -- Effect of radiation on
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9613 , http://hdl.handle.net/10948/723 , Lasers , Laser beams , Lasers in engineering , Nd-YAG lasers , Steel alloys , Surfaces -- Effect of radiation on
- Description: The laser surface hardening process will enhance the hardness profile of automotive components and ensure better process control and predictability of quality as compared to the conventional hardening processes. A 2KW Nd-YAG laser system was used to harden the surface of alloy steel with various process parameters (laser power, focal spot diameter and beam velocity). The results (microhardness, microstructure change and residual stress distribution) were measured and analyzed with Vickers microhardness tester, optical/electron microscope and hole-drilling residual stress equipment. Statistical analyses of the experimental data were used for explaining the relationships between process parameters, microhardness and microstructure. General thermal hardening was applied in the research to show the influence of heating temperature and cooling method on microstructure and mechanical properties. Also, the results were compared with laser surface hardening process from microhardness, microstructure and residual stress to show the advantage of laser surface hardening. Through analysis of the results of the laser surface hardening experiments, a suitable laser power density and interaction time for optimum hardening was obtained. The presented laser surface hardening process can also be applied to other alloy steel surface hardening process.
- Full Text:
- Date Issued: 2010
Learning about water through the African catchment game : the refinement of a role playing simulation game
- Authors: Fraenkel, Linda Anne
- Date: 2010
- Subjects: Water -- South Africa -- Management -- Simulation methods Water -- Management -- Study and teaching Rain and rainfall -- South Africa -- Simulation methods Simulation games in education Role playing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4842 , http://hdl.handle.net/10962/d1005518
- Description: This research has undertaken two key mandates. One was to develop modifications to the African Catchment Game (ACG), a role playing simulation game, in order to simulate rainfall and water management processes representative of the southern African context. The other was to understand what, if any, learning associated with water management issues had taken place as a result of playing the ACG. The modification process took the form of an action research process. The initial modifications were trialed with South African students as part of their undergraduate Geography course offered at Rhodes University, South Africa. Subsequent modifications were implemented over a five month period with three diverse participant groups, namely Finnish, American and South African participants. An interpretive research orientation was employed in order to analyse both the qualitative and quantitative data that was generated. Pre- and Post-Game Questionnaires were used in order to identify the learning and understanding which the participants constructed as a result of playing the ACG. The Chi-Square Test was also applied to each of the pre- and post- questions to establish statistical significance. Subsequent analysis of these questions identified and traced patters and trends associated with learning and understanding across the three game runs. This research study draws on social constructivism and experiential learning as the dominant education theory that underpins it. Results revealed that for all three game runs learning took place. Participants identified dominant themes and environmental dimensions both before and after playing the ACG. The analysis of these responses indicated a deeper awareness of water as a contributing factor for sustainable economic development while the game runs enabled the researcher to adjust the water availability within each game run until rainfall and water management processes representative of a southern African context were successfully simulated in the last game run.
- Full Text:
- Date Issued: 2010
- Authors: Fraenkel, Linda Anne
- Date: 2010
- Subjects: Water -- South Africa -- Management -- Simulation methods Water -- Management -- Study and teaching Rain and rainfall -- South Africa -- Simulation methods Simulation games in education Role playing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4842 , http://hdl.handle.net/10962/d1005518
- Description: This research has undertaken two key mandates. One was to develop modifications to the African Catchment Game (ACG), a role playing simulation game, in order to simulate rainfall and water management processes representative of the southern African context. The other was to understand what, if any, learning associated with water management issues had taken place as a result of playing the ACG. The modification process took the form of an action research process. The initial modifications were trialed with South African students as part of their undergraduate Geography course offered at Rhodes University, South Africa. Subsequent modifications were implemented over a five month period with three diverse participant groups, namely Finnish, American and South African participants. An interpretive research orientation was employed in order to analyse both the qualitative and quantitative data that was generated. Pre- and Post-Game Questionnaires were used in order to identify the learning and understanding which the participants constructed as a result of playing the ACG. The Chi-Square Test was also applied to each of the pre- and post- questions to establish statistical significance. Subsequent analysis of these questions identified and traced patters and trends associated with learning and understanding across the three game runs. This research study draws on social constructivism and experiential learning as the dominant education theory that underpins it. Results revealed that for all three game runs learning took place. Participants identified dominant themes and environmental dimensions both before and after playing the ACG. The analysis of these responses indicated a deeper awareness of water as a contributing factor for sustainable economic development while the game runs enabled the researcher to adjust the water availability within each game run until rainfall and water management processes representative of a southern African context were successfully simulated in the last game run.
- Full Text:
- Date Issued: 2010
Limitations of the land reform in South Africa : an assessment of two farms in the Eastern Cape
- Authors: Tesana, Zola Eric
- Date: 2010
- Subjects: Land reform -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9082 , http://hdl.handle.net/10948/1122 , Land reform -- South Africa -- Eastern Cape
- Description: The government that was voted in, in 1994 initiated and implemented the Land Reform Programme that had three key elements, namely; Land restitution, redistribution and tenure reform. This study was undertaken to examine the limitations that resulted in some of the projects not to succeed. The study took a form of a case study of two farms that were redistributed in 1997 under the Land Redistribution Programme in the Blue Crane Route Municipal area in the Eastern Cape. The findings confirmed a variety of weaknesses that led to the collapse of these farms. Whilst acknowledging that there are some measures that are put in place to address those limitations the, study shows that there is still scope to do more. It is therefore one’s sincere wish that what transpired out of this study will make a positive contribution by providing some elements that can be used as a remedy in advancing the Land Reform Programme.
- Full Text:
- Date Issued: 2010
- Authors: Tesana, Zola Eric
- Date: 2010
- Subjects: Land reform -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9082 , http://hdl.handle.net/10948/1122 , Land reform -- South Africa -- Eastern Cape
- Description: The government that was voted in, in 1994 initiated and implemented the Land Reform Programme that had three key elements, namely; Land restitution, redistribution and tenure reform. This study was undertaken to examine the limitations that resulted in some of the projects not to succeed. The study took a form of a case study of two farms that were redistributed in 1997 under the Land Redistribution Programme in the Blue Crane Route Municipal area in the Eastern Cape. The findings confirmed a variety of weaknesses that led to the collapse of these farms. Whilst acknowledging that there are some measures that are put in place to address those limitations the, study shows that there is still scope to do more. It is therefore one’s sincere wish that what transpired out of this study will make a positive contribution by providing some elements that can be used as a remedy in advancing the Land Reform Programme.
- Full Text:
- Date Issued: 2010
Macrobenthic community structure across an inter- and subtidal gradient in a mangrove estuary
- Authors: Groenewald, Christoff J
- Date: 2010
- Subjects: Mangrove ecology -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa -- Mngazana Estuary , Benthos -- South Africa -- Mngazana Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10695 , http://hdl.handle.net/10948/1240 , Mangrove ecology -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa -- Mngazana Estuary , Benthos -- South Africa -- Mngazana Estuary
- Description: Macrozoobenthic community structure and composition was investigated along a subtidal-intertidal gradient in the Mngazana Estuary. Six transects were sampled between the spring high water mark (HWST) and the bottom of the river channel in the lower estuary. Fifteen replicate samples were collected along each transect using a Van Veen type grab (211 cm2 bite) during each of three sampling sessions. Samples were sieved through a 500 μm mesh bag and the invertebrates stored in bottles for further analysis in the laboratory. Additional grab samples were collected for sediment particle size analysis and organic matter. Physical variables measured at each transect included: salinity, temperature, dissolved oxygen, depth, pH, percentage mud, organic content and turbidity. Sediment compactness was measured at all intertidal transects and additional sediment samples were collected at mid shore and high shore transects for percentage water content analysis. A total of 104 species were recorded along the intertidal-subtidal gradient in the sampling area. Species richness was higher in the subtidal zone compared to the intertidal zone and polychaetes numerically dominated the macrozoobenthic community at most transects, during all three sessions. At high shore transects the community was characterised by having fewer species, consisting mostly of brachyurans, polychaetes and gastropods. Shannon diversity index (H’) was generally higher for subtidal transects (x¯ = 2.3; range: 2.8 to 1) than for intertidal transects (x¯ = 1.4; range: 2.2 to 0.6) indicating that the distribution of individuals among species in the intertidal zone experienced greater variability. Results for Hill’s numbers followed the same trend as Shannon diversity with subtidal communities mostly consisting of abundant species followed by very abundant species. Intertidal communities generally exhibited lower numbers of abundant and very abundant species. Sedimentary characteristics played a major role in structuring benthic communities in comparison to other physico-chemical variables. Organic content and mud content of the substrate were identified as important factors influencing community patterns observed along the subtidal-intertidal gradient. In addition, sediment compactness and water content of the substrate was found to influence intertidal community structure. Subtidal community structure possibly had a greater dependence on seasonal variations in abiotic and/or biotic factors. Cluster dendrograms used in conjunction with MDS ordination mapping revealed that macrozoobenthic communities were generally distinct between high shore intertidal transects iii and subtidal transects. Most species exhibited a broad spatial distribution along the subtidal-intertidal gradient with mid and high shore transects being the exception. Most species also exhibited marked shifts in abundance and this was especially noticeable at the transition between the subtidal and intertidal zone. Two polychaete species, Prionospio sexoculata and Capitella capitata, were very abundant species and featured amongst the most numerically dominant species collected during each sampling session.
- Full Text:
- Date Issued: 2010
- Authors: Groenewald, Christoff J
- Date: 2010
- Subjects: Mangrove ecology -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa -- Mngazana Estuary , Benthos -- South Africa -- Mngazana Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10695 , http://hdl.handle.net/10948/1240 , Mangrove ecology -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa -- Mngazana Estuary , Benthos -- South Africa -- Mngazana Estuary
- Description: Macrozoobenthic community structure and composition was investigated along a subtidal-intertidal gradient in the Mngazana Estuary. Six transects were sampled between the spring high water mark (HWST) and the bottom of the river channel in the lower estuary. Fifteen replicate samples were collected along each transect using a Van Veen type grab (211 cm2 bite) during each of three sampling sessions. Samples were sieved through a 500 μm mesh bag and the invertebrates stored in bottles for further analysis in the laboratory. Additional grab samples were collected for sediment particle size analysis and organic matter. Physical variables measured at each transect included: salinity, temperature, dissolved oxygen, depth, pH, percentage mud, organic content and turbidity. Sediment compactness was measured at all intertidal transects and additional sediment samples were collected at mid shore and high shore transects for percentage water content analysis. A total of 104 species were recorded along the intertidal-subtidal gradient in the sampling area. Species richness was higher in the subtidal zone compared to the intertidal zone and polychaetes numerically dominated the macrozoobenthic community at most transects, during all three sessions. At high shore transects the community was characterised by having fewer species, consisting mostly of brachyurans, polychaetes and gastropods. Shannon diversity index (H’) was generally higher for subtidal transects (x¯ = 2.3; range: 2.8 to 1) than for intertidal transects (x¯ = 1.4; range: 2.2 to 0.6) indicating that the distribution of individuals among species in the intertidal zone experienced greater variability. Results for Hill’s numbers followed the same trend as Shannon diversity with subtidal communities mostly consisting of abundant species followed by very abundant species. Intertidal communities generally exhibited lower numbers of abundant and very abundant species. Sedimentary characteristics played a major role in structuring benthic communities in comparison to other physico-chemical variables. Organic content and mud content of the substrate were identified as important factors influencing community patterns observed along the subtidal-intertidal gradient. In addition, sediment compactness and water content of the substrate was found to influence intertidal community structure. Subtidal community structure possibly had a greater dependence on seasonal variations in abiotic and/or biotic factors. Cluster dendrograms used in conjunction with MDS ordination mapping revealed that macrozoobenthic communities were generally distinct between high shore intertidal transects iii and subtidal transects. Most species exhibited a broad spatial distribution along the subtidal-intertidal gradient with mid and high shore transects being the exception. Most species also exhibited marked shifts in abundance and this was especially noticeable at the transition between the subtidal and intertidal zone. Two polychaete species, Prionospio sexoculata and Capitella capitata, were very abundant species and featured amongst the most numerically dominant species collected during each sampling session.
- Full Text:
- Date Issued: 2010
Macrophyte phenology in a temporarily open/closed Estuary compared with a permanently open Estuary
- Authors: Vromans, Deborah Claire
- Date: 2010
- Subjects: Estuarine ecology -- South Africa -- East Kleinemonde Estuary , Aquatic plants -- South Africa -- East Kleinemonde Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10612 , http://hdl.handle.net/10948/1393 , Estuarine ecology -- South Africa -- East Kleinemonde Estuary , Aquatic plants -- South Africa -- East Kleinemonde Estuary
- Description: Temporarily open/closed estuaries (TOCEs) are unpredictable environments that change in response to mouth condition, which is influenced by freshwater flooding or sea storm surges. The aim of the study was to determine whether macrophyte phenology in a TOCE was event driven rather than cyclically predictable and if it differed from permanently open estuaries (POEs). Macrophyte growth and flowering phenology in response to environmental conditions was investigated in the East Kleinemonde Estuary (TOCE) and the Kowie Estuary (POE) along the eastern coastline of South Africa. The lack of freshwater flooding due to low rainfall coupled with several overwash events resulted in a prolonged period of mouth closure from September 2008 to the end of this study period in 2010. This in turn caused the inundation of the supratidal and intertidal habitats, high water level (> 1.57 m amsl) and high salinity (30 - 42 ppt) in the TOCE. Principle Components Analysis showed that high water level and reduced sediments were the most significant environmental factors affecting macrophyte phenology. Macrophyte phenology in the POE was primarily driven by temperature, sediment redox potential and salinity. The saline high water level and reduced sediment significantly reduced macrophyte cover in all habitats in the TOCE. Macrophytes in the POE maintained high cover abundance due to seasonal re-growth compared to the TOCE where cover declined over the sampling period due to the high water level. Subsequent to water level dropping by as little as 11 - 20 cm in the TOCE, the intertidal species Sarcocornia tegetaria and Salicornia meyeriana completed their life-cycles and produced viable seeds within four and three months of germinating respectively. In contrast, the Sarcocornia hybrid and S. meyeriana in the POE took longer to complete their life-cycles, namely seven and nine months respectively, while S. tegataria did not germinate in situ but reproduced vegetatively despite producing seed. In the TOCE, the submerged species Ruppia cirrhosa and Chara vulgaris completed their life-cycles within five and three months and produced a maximum of 26 242 and 196 998 seeds m-2 respectively. Due to high water level and prolonged inundation, the reproductive periods were shorter for the intertidal and reed and sedge species in the TOCE compared to the POE. Seed output during the two reproduction periods varied between the two estuaries. Sarcocornia decumbens and S. tegetaria produced a substantially higher number of seeds in the TOCE compared to the POE, namely 0 - 102 847 versus 20 661 - 48 576 seeds m-²; and 7 001 - 45 542 versus 1 587 – 16 958 seeds m-² respectively. Seed output in the TOCE was significantly higher in S. tegetaria during the second reproduction period despite the significantly lower plant cover, which may be a function of the stressful environment in the TOCE. Seed production of S. meyeriana was significantly higher in the POE compared to the TOCE, with 264 224 - 640 292 compared with 24 050 - 27 643 seeds m-², due to higher plant cover in the POE. The research suggests that macrophyte phenology in the TOCE was significantly influenced by mouth condition. Further, macrophytes were able to demonstrate considerable phenotypic plasticity in response to changing and unfavourable environmental conditions. These data can be used in mouth management plans and freshwater requirement studies in TOCEs to ensure that macrophytes can complete their life-cycles and produce viable seeds for the safeguarding of habitat persistence and ecological processes. In impacted estuaries where artificial mouth opening is practised and the macrophytes have been severely degraded or extirpated, management should ensure that the intertidal and supratidal habitats are not inundated during peak flowering and seed production periods i.e. late spring to early autumn (November to March).
- Full Text:
- Date Issued: 2010
- Authors: Vromans, Deborah Claire
- Date: 2010
- Subjects: Estuarine ecology -- South Africa -- East Kleinemonde Estuary , Aquatic plants -- South Africa -- East Kleinemonde Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10612 , http://hdl.handle.net/10948/1393 , Estuarine ecology -- South Africa -- East Kleinemonde Estuary , Aquatic plants -- South Africa -- East Kleinemonde Estuary
- Description: Temporarily open/closed estuaries (TOCEs) are unpredictable environments that change in response to mouth condition, which is influenced by freshwater flooding or sea storm surges. The aim of the study was to determine whether macrophyte phenology in a TOCE was event driven rather than cyclically predictable and if it differed from permanently open estuaries (POEs). Macrophyte growth and flowering phenology in response to environmental conditions was investigated in the East Kleinemonde Estuary (TOCE) and the Kowie Estuary (POE) along the eastern coastline of South Africa. The lack of freshwater flooding due to low rainfall coupled with several overwash events resulted in a prolonged period of mouth closure from September 2008 to the end of this study period in 2010. This in turn caused the inundation of the supratidal and intertidal habitats, high water level (> 1.57 m amsl) and high salinity (30 - 42 ppt) in the TOCE. Principle Components Analysis showed that high water level and reduced sediments were the most significant environmental factors affecting macrophyte phenology. Macrophyte phenology in the POE was primarily driven by temperature, sediment redox potential and salinity. The saline high water level and reduced sediment significantly reduced macrophyte cover in all habitats in the TOCE. Macrophytes in the POE maintained high cover abundance due to seasonal re-growth compared to the TOCE where cover declined over the sampling period due to the high water level. Subsequent to water level dropping by as little as 11 - 20 cm in the TOCE, the intertidal species Sarcocornia tegetaria and Salicornia meyeriana completed their life-cycles and produced viable seeds within four and three months of germinating respectively. In contrast, the Sarcocornia hybrid and S. meyeriana in the POE took longer to complete their life-cycles, namely seven and nine months respectively, while S. tegataria did not germinate in situ but reproduced vegetatively despite producing seed. In the TOCE, the submerged species Ruppia cirrhosa and Chara vulgaris completed their life-cycles within five and three months and produced a maximum of 26 242 and 196 998 seeds m-2 respectively. Due to high water level and prolonged inundation, the reproductive periods were shorter for the intertidal and reed and sedge species in the TOCE compared to the POE. Seed output during the two reproduction periods varied between the two estuaries. Sarcocornia decumbens and S. tegetaria produced a substantially higher number of seeds in the TOCE compared to the POE, namely 0 - 102 847 versus 20 661 - 48 576 seeds m-²; and 7 001 - 45 542 versus 1 587 – 16 958 seeds m-² respectively. Seed output in the TOCE was significantly higher in S. tegetaria during the second reproduction period despite the significantly lower plant cover, which may be a function of the stressful environment in the TOCE. Seed production of S. meyeriana was significantly higher in the POE compared to the TOCE, with 264 224 - 640 292 compared with 24 050 - 27 643 seeds m-², due to higher plant cover in the POE. The research suggests that macrophyte phenology in the TOCE was significantly influenced by mouth condition. Further, macrophytes were able to demonstrate considerable phenotypic plasticity in response to changing and unfavourable environmental conditions. These data can be used in mouth management plans and freshwater requirement studies in TOCEs to ensure that macrophytes can complete their life-cycles and produce viable seeds for the safeguarding of habitat persistence and ecological processes. In impacted estuaries where artificial mouth opening is practised and the macrophytes have been severely degraded or extirpated, management should ensure that the intertidal and supratidal habitats are not inundated during peak flowering and seed production periods i.e. late spring to early autumn (November to March).
- Full Text:
- Date Issued: 2010
Managing the implementation of management structure changes at the Eastern Cape Department of Education
- Authors: Muthige, Shumani Ralson
- Date: 2010
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8534 , http://hdl.handle.net/10948/1652
- Description: The Eastern Cape Department of Education has been in the forefront of the media – mostly for the wrong reasons. The major problems that have been reported range from the mismanagement of the feeding schemes, unpaid service providers, lack of adequate infrastructure, corruption committed by the officials, unfilled posts, poor service delivery and the second lowest matriculation pass rate in the country. Although there are many problems, as stated, this study research is focused on the management of change and its implementation in the organisational structure.
- Full Text:
- Date Issued: 2010
- Authors: Muthige, Shumani Ralson
- Date: 2010
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8534 , http://hdl.handle.net/10948/1652
- Description: The Eastern Cape Department of Education has been in the forefront of the media – mostly for the wrong reasons. The major problems that have been reported range from the mismanagement of the feeding schemes, unpaid service providers, lack of adequate infrastructure, corruption committed by the officials, unfilled posts, poor service delivery and the second lowest matriculation pass rate in the country. Although there are many problems, as stated, this study research is focused on the management of change and its implementation in the organisational structure.
- Full Text:
- Date Issued: 2010
Managing the perceptions about affirmitive action (AA)
- Authors: Swartbooi, Aurick Devlin
- Date: 2010
- Subjects: Affirmative action programs -- South Africa , Affirmative action programs -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8684 , http://hdl.handle.net/10948/1120 , Affirmative action programs -- South Africa , Affirmative action programs -- Law and legislation -- South Africa
- Description: The main research problem focused on the effective management of the perceptions about Affirmative Action (AA). A literature study and a survey were conducted to investigate the extent and nature of perceptions, the effect of these perceptions on labour and personal relations, current and suggested management practice of the perceptions of AA. A definition of AA, earlier measures of AA, the implementation of AA in the South African context, the stages of AA, theories, relevant legislation, perceptions and the management thereof are discussed. The survey was conducted at the George and Beaufort West District offices of the Department of Rural Development and Land Reform (DRDLR) with a response rate of 78.95 percent. The perceptions about AA can be managed effectively by complying with legislation, by involving and making all levels of employees responsible for the achievement of employment equity, skills development, personal development, consultation and communication.
- Full Text:
- Date Issued: 2010
- Authors: Swartbooi, Aurick Devlin
- Date: 2010
- Subjects: Affirmative action programs -- South Africa , Affirmative action programs -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8684 , http://hdl.handle.net/10948/1120 , Affirmative action programs -- South Africa , Affirmative action programs -- Law and legislation -- South Africa
- Description: The main research problem focused on the effective management of the perceptions about Affirmative Action (AA). A literature study and a survey were conducted to investigate the extent and nature of perceptions, the effect of these perceptions on labour and personal relations, current and suggested management practice of the perceptions of AA. A definition of AA, earlier measures of AA, the implementation of AA in the South African context, the stages of AA, theories, relevant legislation, perceptions and the management thereof are discussed. The survey was conducted at the George and Beaufort West District offices of the Department of Rural Development and Land Reform (DRDLR) with a response rate of 78.95 percent. The perceptions about AA can be managed effectively by complying with legislation, by involving and making all levels of employees responsible for the achievement of employment equity, skills development, personal development, consultation and communication.
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- Date Issued: 2010