Curating the reviled, beloved and quotidian: a retrospective of Vladimir Tretchikoff
- Authors: Lamprecht, Andrew Paul
- Date: 2011
- Subjects: Tretchikoff, Vladimir -- Criticism and interpretation Painters -- South Africa -- Criticism and interpretation Curatorship -- South Africa -- Art Kitsch
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2407 , http://hdl.handle.net/10962/d1002203
- Description: This thesis aims to contextualise my curation of 'Tretchikoff: The People's Painter' at the Iziko South African National Gallery by outlining the process by which I came to embark on this project and to examine the concepts of mass art and kitsch in relation to the painter. Mass art, in Noel Carroll's explication of the term, is art that utilises industrial processes of replication. Carroll argues that this leads to specific formal and structural tendencies in this art which have much in common with the pejorative concept of kitsch, or art that is lacking in taste or effuses excessive emotion. The latter term was and continues to be applied to Tretchikoff. Although some have attempted to 'reclaim' the word as a positive concept the negative associations that link this term to Tretchikoff are strong. Interrogating these concepts led me to decide to curate TretchikofPs retrospective by focusing on his painting and not including the prints for which he was so well known. Awareness of the complex associations and 'received knowledge' that his prints engender has influenced several curatorial decisions that I have taken. I consider the intellectual underpinnings of my curatorial strategy and argue for an 'open' exhibition which gives the viewer the opportunity to assess his work and legacy in an objective manner, free from as much curatorial mediation and didacticsm as possible. There are no answers to be offered in my curation of Tretchikxiff the People's Painter, rather I have aimed to set up dialogues, discussions, confrontations and challenges; I have offered simple relationships rather than complex juxtapositions I have aimed to position the artwork as the centre of the engagement relative to the viewer.
- Full Text:
- Date Issued: 2011
- Authors: Lamprecht, Andrew Paul
- Date: 2011
- Subjects: Tretchikoff, Vladimir -- Criticism and interpretation Painters -- South Africa -- Criticism and interpretation Curatorship -- South Africa -- Art Kitsch
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2407 , http://hdl.handle.net/10962/d1002203
- Description: This thesis aims to contextualise my curation of 'Tretchikoff: The People's Painter' at the Iziko South African National Gallery by outlining the process by which I came to embark on this project and to examine the concepts of mass art and kitsch in relation to the painter. Mass art, in Noel Carroll's explication of the term, is art that utilises industrial processes of replication. Carroll argues that this leads to specific formal and structural tendencies in this art which have much in common with the pejorative concept of kitsch, or art that is lacking in taste or effuses excessive emotion. The latter term was and continues to be applied to Tretchikoff. Although some have attempted to 'reclaim' the word as a positive concept the negative associations that link this term to Tretchikoff are strong. Interrogating these concepts led me to decide to curate TretchikofPs retrospective by focusing on his painting and not including the prints for which he was so well known. Awareness of the complex associations and 'received knowledge' that his prints engender has influenced several curatorial decisions that I have taken. I consider the intellectual underpinnings of my curatorial strategy and argue for an 'open' exhibition which gives the viewer the opportunity to assess his work and legacy in an objective manner, free from as much curatorial mediation and didacticsm as possible. There are no answers to be offered in my curation of Tretchikxiff the People's Painter, rather I have aimed to set up dialogues, discussions, confrontations and challenges; I have offered simple relationships rather than complex juxtapositions I have aimed to position the artwork as the centre of the engagement relative to the viewer.
- Full Text:
- Date Issued: 2011
Customer relationship management practiced by KOSAB
- Authors: Felix, Amoah
- Date: 2011
- Subjects: Customer relations , Customer services , Consumer satisfaction , Customer loyalty
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:8635 , http://hdl.handle.net/10948/d1008046 , Customer relations , Customer services , Consumer satisfaction , Customer loyalty
- Description: Customer relationship management (CRM) presents a new paradigm shift to the old traditional marketing strategies that are known and practiced by many organisations in South Africa and across the globe. Competition is not an excuse for failure anymore. Organisations that do not have any concrete strategies in dealing with the customer will not survive in the market. The ultimate goal of CRM is to enable organisations to forge closer ties with the customer so that a solid bond can be created to enhance loyalty and satisfaction. The goal for this research was to identify the CRM strategies used by a single organisation and thereafter suggest improvements to enhance customer loyalty. The results of the study could assist the management of the organisation to improve the CRM strategies which will hopefully enhance retention and prevent customer attrition. A literature review was conducted to unveil various elements of CRM, and strategies that can attract and retain customers. It helped in identifying themes for the empirical study. An in-depth interview was conducted with the general manager of the organisation to gauge his perception, and CRM practices in the organisation. An interview guide was used during the interview process. Four main topics namely: implementation of CRM, customer loyalty, customer complaints and conflict, and employees training and motivation were utilised for the interview guide and followed by further probing. Based on the responses obtained, analyses were made by comparing the responses to what literature revealed so that shortcomings could easily be identified.The study revealed that there were several inconsistencies with what was practised by the organisation and what the literature study revealed. Bearing in mind the shortcomings identified in the empirical study, the researcher made the following recommendations. The CRM implementation approach needs to be carefully planned with a clear defined vision and mission statement that focus on customer centredness. The organisation needs to invest in modern and innovative channels of communication and strategic partnership to reach the right customer. The organisation has to develop effective market segmentation and targeting to know the customer well. Consistent and highly relevant customer experiences should be drawn-on to fulfill the organisation’s promise of trust and reliability. The organisation should adopt competitive pricing strategy to limit customer sensitivity on price. The organisation should invest in employees’ development and welfare. Further research can be conducted to investigate the perception of other food retailers on the CRM strategies practiced. Further research can also be conducted in the organisation to investigate the perception of employees and customers on the CRM strategies practised.
- Full Text:
- Date Issued: 2011
- Authors: Felix, Amoah
- Date: 2011
- Subjects: Customer relations , Customer services , Consumer satisfaction , Customer loyalty
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:8635 , http://hdl.handle.net/10948/d1008046 , Customer relations , Customer services , Consumer satisfaction , Customer loyalty
- Description: Customer relationship management (CRM) presents a new paradigm shift to the old traditional marketing strategies that are known and practiced by many organisations in South Africa and across the globe. Competition is not an excuse for failure anymore. Organisations that do not have any concrete strategies in dealing with the customer will not survive in the market. The ultimate goal of CRM is to enable organisations to forge closer ties with the customer so that a solid bond can be created to enhance loyalty and satisfaction. The goal for this research was to identify the CRM strategies used by a single organisation and thereafter suggest improvements to enhance customer loyalty. The results of the study could assist the management of the organisation to improve the CRM strategies which will hopefully enhance retention and prevent customer attrition. A literature review was conducted to unveil various elements of CRM, and strategies that can attract and retain customers. It helped in identifying themes for the empirical study. An in-depth interview was conducted with the general manager of the organisation to gauge his perception, and CRM practices in the organisation. An interview guide was used during the interview process. Four main topics namely: implementation of CRM, customer loyalty, customer complaints and conflict, and employees training and motivation were utilised for the interview guide and followed by further probing. Based on the responses obtained, analyses were made by comparing the responses to what literature revealed so that shortcomings could easily be identified.The study revealed that there were several inconsistencies with what was practised by the organisation and what the literature study revealed. Bearing in mind the shortcomings identified in the empirical study, the researcher made the following recommendations. The CRM implementation approach needs to be carefully planned with a clear defined vision and mission statement that focus on customer centredness. The organisation needs to invest in modern and innovative channels of communication and strategic partnership to reach the right customer. The organisation has to develop effective market segmentation and targeting to know the customer well. Consistent and highly relevant customer experiences should be drawn-on to fulfill the organisation’s promise of trust and reliability. The organisation should adopt competitive pricing strategy to limit customer sensitivity on price. The organisation should invest in employees’ development and welfare. Further research can be conducted to investigate the perception of other food retailers on the CRM strategies practiced. Further research can also be conducted in the organisation to investigate the perception of employees and customers on the CRM strategies practised.
- Full Text:
- Date Issued: 2011
Cyclic voltammetry and spectroelectrochemistry of a novel manganese phthalocyanine substituted with hexynyl groups
- Quinton, Damien, Antunes, Edith M, Griveau, Sophie, Nyokong, Tebello, Bedioui, Fethi
- Authors: Quinton, Damien , Antunes, Edith M , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248450 , vital:51687 , xlink:href="https://doi.org/10.1016/j.inoche.2010.11.029"
- Description: We report here on the synthesis of a new manganese phthalocyanine complex, namely Mn tetrakis(5-hexyn-oxy) phthalocyanine (3), specifically designed to possess an alkyne moiety for its potential use in controlled immobilization on electrodes via the so called “click” chemistry reaction. The electrochemical activity of complex 3 was investigated by cyclic voltammetry and the nature of the observed redox couples was elucidated by spectroelectrochemistry. This work has also shown that the reduction of Mn(III)Pc complex to Mn(II)Pc is accompanied by the formation of MnPc μ-oxo species. Further reduction results in the formation of Mn(II)Pc(− 3) rather than Mn(I)Pc(− 2).
- Full Text:
- Date Issued: 2011
- Authors: Quinton, Damien , Antunes, Edith M , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248450 , vital:51687 , xlink:href="https://doi.org/10.1016/j.inoche.2010.11.029"
- Description: We report here on the synthesis of a new manganese phthalocyanine complex, namely Mn tetrakis(5-hexyn-oxy) phthalocyanine (3), specifically designed to possess an alkyne moiety for its potential use in controlled immobilization on electrodes via the so called “click” chemistry reaction. The electrochemical activity of complex 3 was investigated by cyclic voltammetry and the nature of the observed redox couples was elucidated by spectroelectrochemistry. This work has also shown that the reduction of Mn(III)Pc complex to Mn(II)Pc is accompanied by the formation of MnPc μ-oxo species. Further reduction results in the formation of Mn(II)Pc(− 3) rather than Mn(I)Pc(− 2).
- Full Text:
- Date Issued: 2011
Delivering a personalised video service using IPTV
- Shibeshi, Zelalem S, Ndakunda, Shanga, Terzoli, Alfredo, Bradshaw, Karen L
- Authors: Shibeshi, Zelalem S , Ndakunda, Shanga , Terzoli, Alfredo , Bradshaw, Karen L
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429163 , vital:72564 , https://ieeexplore.ieee.org/abstract/document/5746086
- Description: Video oriented services are taking the lead in terms of revenue in the current Internet environment. In order to tap this revenue, Telcos are resorting to serious measures such as moving to Next Generation Network (NGN) where they can provide QoS for services that demand this feature, such as, IPTV. IPTV is more than just what its name implies and includes various types of additional services to make the TV a better entertainment and communication environment. Various innovative IPTV services have been proposed and developed by researchers and practitioners, including personalized advertisement, personalized EPG (Electronic Program Guide), and personalized VoD (Video on Demand). In this paper we introduce a new IPTV service called, the personalized dynamic video delivery service, which sends new video alerts (like breaking news alert) to subscribed users and notifies them when the video is available. If desired, users can watch the video automatically by switching from what they are currently watching without requiring explicitly a new video setup. Users can configure their profile and also set a policy on the way they wish to be notified and the types of video they wish to be alerted to. The paper describes the issues surrounding the delivery of this service and presents the architecture and the various open source technologies that are used to develop the service.
- Full Text:
- Date Issued: 2011
- Authors: Shibeshi, Zelalem S , Ndakunda, Shanga , Terzoli, Alfredo , Bradshaw, Karen L
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429163 , vital:72564 , https://ieeexplore.ieee.org/abstract/document/5746086
- Description: Video oriented services are taking the lead in terms of revenue in the current Internet environment. In order to tap this revenue, Telcos are resorting to serious measures such as moving to Next Generation Network (NGN) where they can provide QoS for services that demand this feature, such as, IPTV. IPTV is more than just what its name implies and includes various types of additional services to make the TV a better entertainment and communication environment. Various innovative IPTV services have been proposed and developed by researchers and practitioners, including personalized advertisement, personalized EPG (Electronic Program Guide), and personalized VoD (Video on Demand). In this paper we introduce a new IPTV service called, the personalized dynamic video delivery service, which sends new video alerts (like breaking news alert) to subscribed users and notifies them when the video is available. If desired, users can watch the video automatically by switching from what they are currently watching without requiring explicitly a new video setup. Users can configure their profile and also set a policy on the way they wish to be notified and the types of video they wish to be alerted to. The paper describes the issues surrounding the delivery of this service and presents the architecture and the various open source technologies that are used to develop the service.
- Full Text:
- Date Issued: 2011
Desegregation and socio-spatial integration in residential suburbs in East London, South Africa (1993-2008)
- Authors: Bwalya, John
- Date: 2011
- Subjects: City planning -- South Africa -- East London , Apartheid -- South Africa -- Eastern Cape , Migration, Internal -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Geography)
- Identifier: vital:11504 , http://hdl.handle.net/10353/336 , City planning -- South Africa -- East London , Apartheid -- South Africa -- Eastern Cape , Migration, Internal -- South Africa -- Eastern Cape
- Description: This study used integration as the overarching conceptual framework to investigate socio-spatial integration in post-apartheid South Africa. The study adopted the embedded case study design to investigate the spatial and social aspects of integration in former white residential suburbs in East London, South Africa. Recognising that integration occurred in different registers, this study used data from the South African Property Transfer Guide (SAPTG) database to investigate spatial-temporal integration in East London‟s residential suburbs from 1993 to 2008. A total of 21,683 residential property transfers were reviewed in 46 suburbs, and transfers to Blacks were identified. The residential property transfers were mapped to identify the nature of spatial integration. To investigate social integration, in-depth personal interviews were conducted on a purposively drawn sample of residents in the three case study suburbs of Southernwood, Cambridge and Gonubie. The interviews focused on three proxy indicators of social capital at neighbourhood level. The results of the study showed that post-apartheid spatial integration in East London closely followed the class-based residential template. Contrary to predictions prior to, and following apartheid‟s demise, the study showed that spatial integration occurred without racial conflicts. The study also found that social integration in the residential suburbs reflected the neighbourhood context and personal preferences, and was highly fluid. Although feelings of racial distance were evident, there were also indications of social cohesion, which were dynamic and uneven in time and space. Based on the data and the dialectical nature of spatial and social integration, the study concluded that fragmentation and integration are likely to continue coexisting in the South African city.
- Full Text:
- Date Issued: 2011
- Authors: Bwalya, John
- Date: 2011
- Subjects: City planning -- South Africa -- East London , Apartheid -- South Africa -- Eastern Cape , Migration, Internal -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Geography)
- Identifier: vital:11504 , http://hdl.handle.net/10353/336 , City planning -- South Africa -- East London , Apartheid -- South Africa -- Eastern Cape , Migration, Internal -- South Africa -- Eastern Cape
- Description: This study used integration as the overarching conceptual framework to investigate socio-spatial integration in post-apartheid South Africa. The study adopted the embedded case study design to investigate the spatial and social aspects of integration in former white residential suburbs in East London, South Africa. Recognising that integration occurred in different registers, this study used data from the South African Property Transfer Guide (SAPTG) database to investigate spatial-temporal integration in East London‟s residential suburbs from 1993 to 2008. A total of 21,683 residential property transfers were reviewed in 46 suburbs, and transfers to Blacks were identified. The residential property transfers were mapped to identify the nature of spatial integration. To investigate social integration, in-depth personal interviews were conducted on a purposively drawn sample of residents in the three case study suburbs of Southernwood, Cambridge and Gonubie. The interviews focused on three proxy indicators of social capital at neighbourhood level. The results of the study showed that post-apartheid spatial integration in East London closely followed the class-based residential template. Contrary to predictions prior to, and following apartheid‟s demise, the study showed that spatial integration occurred without racial conflicts. The study also found that social integration in the residential suburbs reflected the neighbourhood context and personal preferences, and was highly fluid. Although feelings of racial distance were evident, there were also indications of social cohesion, which were dynamic and uneven in time and space. Based on the data and the dialectical nature of spatial and social integration, the study concluded that fragmentation and integration are likely to continue coexisting in the South African city.
- Full Text:
- Date Issued: 2011
Designer ligands : the search for metal ion selectivity
- Authors: Kaye, Perry T
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6576 , http://hdl.handle.net/10962/d1004139
- Description: The paper reviews research conducted at Rhodes University towards the development of metal-selective ligands. The research has focused on the rational design, synthesis and evaluation of novel ligands for use in the formation of copper complexes as biomimetic models of the metalloenzyme, tyrosinase, and for the selective extraction of silver, nickel and platinum group metal ions in the presence of contaminating metal ions. Attention has also been given to the development of efficient, metal-selective molecular imprinted polymers.
- Full Text:
- Date Issued: 2011
- Authors: Kaye, Perry T
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6576 , http://hdl.handle.net/10962/d1004139
- Description: The paper reviews research conducted at Rhodes University towards the development of metal-selective ligands. The research has focused on the rational design, synthesis and evaluation of novel ligands for use in the formation of copper complexes as biomimetic models of the metalloenzyme, tyrosinase, and for the selective extraction of silver, nickel and platinum group metal ions in the presence of contaminating metal ions. Attention has also been given to the development of efficient, metal-selective molecular imprinted polymers.
- Full Text:
- Date Issued: 2011
Destination management: critical success factors for Knysna as an international tourism destination
- Authors: Gie, Jannie Adriaan
- Date: 2011
- Subjects: Place marketing -- South Africa -- Knysna , Tourism -- Marketing -- South Africa -- Knysna , Tourism management -- South Africa -- Knysna , Tourism -- South Africa -- Knysna
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8641 , http://hdl.handle.net/10948/1433 , Place marketing -- South Africa -- Knysna , Tourism -- Marketing -- South Africa -- Knysna , Tourism management -- South Africa -- Knysna , Tourism -- South Africa -- Knysna
- Description: Tourism, as an industry, has a great impact on society and the environment. It adds to economic growth; and therefore, many governments try to enhance tourism because they realise the potential economic returns. Within each country, there are towns or cities that have great tourism potential. In South Africa, Knysna is a good example of a small town with great tourism potential. This study examines the critical success factors of tourism destination marketing for the town of Knysna. Most South Africans see Knysna as an ideal holiday destination, as it has the infrastructure and offerings to make tourists' holidays unforgettable. However, unfortunately, in recent times bad publicity has caused Knysna's image to be damaged. To improve the town's image and to add to its economic growth, tourism bodies and the community have had to work together to ensure that Knysna sustains its position in the national and international tourism markets. The best way to achieve this is through effective destination management and destination marketing. The aim of this study is to determine how effective destination management and destination marketing can lead to competitive growth and to enhancing a destination's position in the tourism industry, and also to providing a set of practical guidelines for the successful implementation of the destination marketing of the town of Knysna. A literature study was conducted to find out what the theory reveals about destination management and marketing. This was followed by an empirical survey; and this survey was conducted in Knysna in the Western Cape. The results of the survey were compared with the literature and tourism operators and managers can now use these as a point of departure to fill any gaps, thus leading to the optimal positioning of Knysna on the international tourism map.
- Full Text:
- Date Issued: 2011
- Authors: Gie, Jannie Adriaan
- Date: 2011
- Subjects: Place marketing -- South Africa -- Knysna , Tourism -- Marketing -- South Africa -- Knysna , Tourism management -- South Africa -- Knysna , Tourism -- South Africa -- Knysna
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8641 , http://hdl.handle.net/10948/1433 , Place marketing -- South Africa -- Knysna , Tourism -- Marketing -- South Africa -- Knysna , Tourism management -- South Africa -- Knysna , Tourism -- South Africa -- Knysna
- Description: Tourism, as an industry, has a great impact on society and the environment. It adds to economic growth; and therefore, many governments try to enhance tourism because they realise the potential economic returns. Within each country, there are towns or cities that have great tourism potential. In South Africa, Knysna is a good example of a small town with great tourism potential. This study examines the critical success factors of tourism destination marketing for the town of Knysna. Most South Africans see Knysna as an ideal holiday destination, as it has the infrastructure and offerings to make tourists' holidays unforgettable. However, unfortunately, in recent times bad publicity has caused Knysna's image to be damaged. To improve the town's image and to add to its economic growth, tourism bodies and the community have had to work together to ensure that Knysna sustains its position in the national and international tourism markets. The best way to achieve this is through effective destination management and destination marketing. The aim of this study is to determine how effective destination management and destination marketing can lead to competitive growth and to enhancing a destination's position in the tourism industry, and also to providing a set of practical guidelines for the successful implementation of the destination marketing of the town of Knysna. A literature study was conducted to find out what the theory reveals about destination management and marketing. This was followed by an empirical survey; and this survey was conducted in Knysna in the Western Cape. The results of the survey were compared with the literature and tourism operators and managers can now use these as a point of departure to fill any gaps, thus leading to the optimal positioning of Knysna on the international tourism map.
- Full Text:
- Date Issued: 2011
Detection and identification of plasmodium species causing malaria in Malawi using rapid diagnostic tests
- Authors: Tegha, Gerald Loiswayo
- Date: 2011
- Subjects: Malaria -- Diagnosis -- Malawi , Plasmodium
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10127 , http://hdl.handle.net/10948/d1021240
- Description: Malaria represents one of the oldest documented diseases among humans and even today organisms in the genus Plasmodium kill more people than any other infectious disease, especially in tropical and subtropical areas. The four most common species which infect humans are Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale and Plasmodium malaria. Of these four species, Plasmodium falciparum and Plasmodium vivax account for 95 percent of infections globally. Microscopy has been used since early days for the diagnosis of malaria because this method is simple, does not require highly equipped facilities, and in most cases enables differentiation among the species causing malaria in humans when performed by skilled microscopy readers. However, this method has been misleading in identifying parasite species, especially in the case of low level parasitemia, a mixed parasite infection, or modification by drug treatment as well as in placental malaria. Malaria rapid diagnostic tests (RDT) have played a major role in malaria management; particularly in providing blood based diagnosis in remote locations where microscopy based diagnosis is unavailable. These diagnostic tests are fast and easy to perform and do not require electricity or specific equipment. As part of strengthening malaria diagnostics in Malawi, the Ministry of Health and Population strongly recommends the use of malaria RDT’s at all levels of the health care delivery system. However, malaria microscopy remains a gold standard test for malaria. All patients (regardless of age) with suspected uncomplicated malaria should have a confirmed diagnosis with malaria RDT before anti-malaria treatment is administered. Based on field performance evaluations that assessed performance, quality control and production capacities of the manufacturing companies of malaria RDT’s, the Ministry of Health and Population recommended two brands of Histidine Rich Protein 2 (HRP-2), RDT’s for use in Malawi. These are SD Bioline malaria Ag Pf and the New Paracheck malaria Ag Pf. All these RDT’s are able to detect only P. falciparum. However, other species have been reported to exist in the country and there is a need to find proper RDT’s which will be able to detect all other species including P. falciparum. The main aim of this study was to evaluate Paramax-3 Pf/Pv/Pan RDT (Zephyr Biomedicals, India), if used in Malawi, could be able to detect and identify the different species of Plasmodium causing malaria in Malawi. The study recruited a total of 250 adult and infants at Bwaila Hospital in Lilongwe, Malawi. Study results showed that the overall sensitivity and specificity of the Paramax-3 RDT used in the study were 100 percent and 83 percent respectively. However, it was observed that the RDT test was not able to identify the P. ovale, and in some cases, the RDT test was positive for P. falciparum when the PCR identified the species as P. ovale. No P. vivax was detected both by RDT and PCR. This study was able to detect and identify the presence of P. malaria and P. ovale in Malawi apart from the P. falciparum. There were no significant differences between microscopy results compared to both the RDT and the PCR, with 94 percent and 98 percent sensitivities of R1 and R2 compared to RDT, as well as 94 percent and 96 percent sensitivities for R1 and R2 compared to PCR respectively. Both R1 and R2 had low specificities for example, R1 had 72 percent and R2 had 80 percent compared to RDT. Comparing R1 and R2 to PCR, the sensitivities were 64.9 percent and 67.2 percent respectively. However, the readers had difficulties differentiating the different species microscopically. The history of anti-malaria treatment had no significant effect on the outcome of the results in both the RDT and PCR.
- Full Text:
- Date Issued: 2011
- Authors: Tegha, Gerald Loiswayo
- Date: 2011
- Subjects: Malaria -- Diagnosis -- Malawi , Plasmodium
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10127 , http://hdl.handle.net/10948/d1021240
- Description: Malaria represents one of the oldest documented diseases among humans and even today organisms in the genus Plasmodium kill more people than any other infectious disease, especially in tropical and subtropical areas. The four most common species which infect humans are Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale and Plasmodium malaria. Of these four species, Plasmodium falciparum and Plasmodium vivax account for 95 percent of infections globally. Microscopy has been used since early days for the diagnosis of malaria because this method is simple, does not require highly equipped facilities, and in most cases enables differentiation among the species causing malaria in humans when performed by skilled microscopy readers. However, this method has been misleading in identifying parasite species, especially in the case of low level parasitemia, a mixed parasite infection, or modification by drug treatment as well as in placental malaria. Malaria rapid diagnostic tests (RDT) have played a major role in malaria management; particularly in providing blood based diagnosis in remote locations where microscopy based diagnosis is unavailable. These diagnostic tests are fast and easy to perform and do not require electricity or specific equipment. As part of strengthening malaria diagnostics in Malawi, the Ministry of Health and Population strongly recommends the use of malaria RDT’s at all levels of the health care delivery system. However, malaria microscopy remains a gold standard test for malaria. All patients (regardless of age) with suspected uncomplicated malaria should have a confirmed diagnosis with malaria RDT before anti-malaria treatment is administered. Based on field performance evaluations that assessed performance, quality control and production capacities of the manufacturing companies of malaria RDT’s, the Ministry of Health and Population recommended two brands of Histidine Rich Protein 2 (HRP-2), RDT’s for use in Malawi. These are SD Bioline malaria Ag Pf and the New Paracheck malaria Ag Pf. All these RDT’s are able to detect only P. falciparum. However, other species have been reported to exist in the country and there is a need to find proper RDT’s which will be able to detect all other species including P. falciparum. The main aim of this study was to evaluate Paramax-3 Pf/Pv/Pan RDT (Zephyr Biomedicals, India), if used in Malawi, could be able to detect and identify the different species of Plasmodium causing malaria in Malawi. The study recruited a total of 250 adult and infants at Bwaila Hospital in Lilongwe, Malawi. Study results showed that the overall sensitivity and specificity of the Paramax-3 RDT used in the study were 100 percent and 83 percent respectively. However, it was observed that the RDT test was not able to identify the P. ovale, and in some cases, the RDT test was positive for P. falciparum when the PCR identified the species as P. ovale. No P. vivax was detected both by RDT and PCR. This study was able to detect and identify the presence of P. malaria and P. ovale in Malawi apart from the P. falciparum. There were no significant differences between microscopy results compared to both the RDT and the PCR, with 94 percent and 98 percent sensitivities of R1 and R2 compared to RDT, as well as 94 percent and 96 percent sensitivities for R1 and R2 compared to PCR respectively. Both R1 and R2 had low specificities for example, R1 had 72 percent and R2 had 80 percent compared to RDT. Comparing R1 and R2 to PCR, the sensitivities were 64.9 percent and 67.2 percent respectively. However, the readers had difficulties differentiating the different species microscopically. The history of anti-malaria treatment had no significant effect on the outcome of the results in both the RDT and PCR.
- Full Text:
- Date Issued: 2011
Determinants of foreign direct investments in the motor industry in South Africa
- Authors: Onceya, Siyabulela
- Date: 2011
- Subjects: Investments, Foreign -- South Africa , Automobile industry and trade -- South Africa , Motor industry -- South Africa , Industrial policy -- South Africa
- Language: English
- Type: Thesis , Masters , M Com
- Identifier: vital:11459 , http://hdl.handle.net/10353/545 , Investments, Foreign -- South Africa , Automobile industry and trade -- South Africa , Motor industry -- South Africa , Industrial policy -- South Africa
- Description: The recent surge in foreign capital inflows into developing countries has generated interest among researchers wanting to analyse the major determinants of Foreign Direct Investments in the motor industry (FDIsm). This dissertation investigates the determinants of FDI in the motor industry in South Africa. The underpinning theoretical literature in this study is the Micro-level theory of FDI and the Eclectic theory as well as empirical literature from several authors. The study used quarterly time series data, which covers the period 1994q1- 2008q4. FDIs are modeled as the function of economic growth, interest rates, exchange rate, education and the openness of the country. The variables in the model are tested for stationarity. Cointegration analysis was also used to test for long run relationships between the variables. The trace and the maximum eigenvalue tests suggest that there are at least two cointegration relationships, an error correction modelling technique is used to establish the determinants of foreign direct investment. The error correction model was estimated which provided both long run and short run parameter estimates. The results show that economic growth, education and the openness of the country are positively related to foreign direct investment in the motor industry. Interest rates and exchange rates negatively affect foreign direct investment in the motor industry in South Africa. The results of this study are also supported by the impulse response and variance decomposition tests. The policy recommendation that emanate from this study is that efforts should be made to boost the level of economic growth in order to enhance and attract more foreign investors. It is therefore important for the government to purse policies that will encourage economic growth.
- Full Text:
- Date Issued: 2011
- Authors: Onceya, Siyabulela
- Date: 2011
- Subjects: Investments, Foreign -- South Africa , Automobile industry and trade -- South Africa , Motor industry -- South Africa , Industrial policy -- South Africa
- Language: English
- Type: Thesis , Masters , M Com
- Identifier: vital:11459 , http://hdl.handle.net/10353/545 , Investments, Foreign -- South Africa , Automobile industry and trade -- South Africa , Motor industry -- South Africa , Industrial policy -- South Africa
- Description: The recent surge in foreign capital inflows into developing countries has generated interest among researchers wanting to analyse the major determinants of Foreign Direct Investments in the motor industry (FDIsm). This dissertation investigates the determinants of FDI in the motor industry in South Africa. The underpinning theoretical literature in this study is the Micro-level theory of FDI and the Eclectic theory as well as empirical literature from several authors. The study used quarterly time series data, which covers the period 1994q1- 2008q4. FDIs are modeled as the function of economic growth, interest rates, exchange rate, education and the openness of the country. The variables in the model are tested for stationarity. Cointegration analysis was also used to test for long run relationships between the variables. The trace and the maximum eigenvalue tests suggest that there are at least two cointegration relationships, an error correction modelling technique is used to establish the determinants of foreign direct investment. The error correction model was estimated which provided both long run and short run parameter estimates. The results show that economic growth, education and the openness of the country are positively related to foreign direct investment in the motor industry. Interest rates and exchange rates negatively affect foreign direct investment in the motor industry in South Africa. The results of this study are also supported by the impulse response and variance decomposition tests. The policy recommendation that emanate from this study is that efforts should be made to boost the level of economic growth in order to enhance and attract more foreign investors. It is therefore important for the government to purse policies that will encourage economic growth.
- Full Text:
- Date Issued: 2011
Developing a help-desk system for a multi-purpose ICT platform in a marginalised setting
- Authors: Makombe, Farai
- Date: 2011
- Subjects: Computer industry -- Customer services , Rural development projects -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Case-based reasoning , Telecommunication -- Technological innovations
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11381 , http://hdl.handle.net/10353/315 , Computer industry -- Customer services , Rural development projects -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Case-based reasoning , Telecommunication -- Technological innovations
- Description: Attempts to bridge the digital divide between urban and rural Information and Communications Technology (ICT) users have led to the deployment of ICT platforms in remote rural areas. This puts an increased demand for skilled support in rural ICT platforms to assist users in resolving technical problems that they face on a daily basis. A web based help desk system is developed and implemented to allow knowledge sharing and collaboration amongst users and experts as a way of ensuring the technical sustainability of the Siyakhula Living Lab, a remote rural based Information and Communications Technology (ICT4D) intervention. The research describes the use of Transactional and Innovation & Creative knowledge management strategies and their associated applications such as case-based reasoning (CBR) methods and collaborative knowledge approaches to develop a help desk support system for a geographically distributed multipurpose ICT centre in Dwesa, a rural remote area in the Eastern Cape Province, South Africa. The system implemented in this study has been validated for functional adequacy and usability within the Siyakhula Living Lab. The results of the evaluation are presented in this thesis to provide the initial validation of the effectiveness of the help desk system. Keywords: ICT4D, ICT, Case-Based Reasoning; Collaborative Knowledge, Technical Sustainability, Help Desk Systems, Siyakhula Living Lab Forums, Issue Tracking, Rural Users, South Africa
- Full Text:
- Date Issued: 2011
- Authors: Makombe, Farai
- Date: 2011
- Subjects: Computer industry -- Customer services , Rural development projects -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Case-based reasoning , Telecommunication -- Technological innovations
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11381 , http://hdl.handle.net/10353/315 , Computer industry -- Customer services , Rural development projects -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Case-based reasoning , Telecommunication -- Technological innovations
- Description: Attempts to bridge the digital divide between urban and rural Information and Communications Technology (ICT) users have led to the deployment of ICT platforms in remote rural areas. This puts an increased demand for skilled support in rural ICT platforms to assist users in resolving technical problems that they face on a daily basis. A web based help desk system is developed and implemented to allow knowledge sharing and collaboration amongst users and experts as a way of ensuring the technical sustainability of the Siyakhula Living Lab, a remote rural based Information and Communications Technology (ICT4D) intervention. The research describes the use of Transactional and Innovation & Creative knowledge management strategies and their associated applications such as case-based reasoning (CBR) methods and collaborative knowledge approaches to develop a help desk support system for a geographically distributed multipurpose ICT centre in Dwesa, a rural remote area in the Eastern Cape Province, South Africa. The system implemented in this study has been validated for functional adequacy and usability within the Siyakhula Living Lab. The results of the evaluation are presented in this thesis to provide the initial validation of the effectiveness of the help desk system. Keywords: ICT4D, ICT, Case-Based Reasoning; Collaborative Knowledge, Technical Sustainability, Help Desk Systems, Siyakhula Living Lab Forums, Issue Tracking, Rural Users, South Africa
- Full Text:
- Date Issued: 2011
Developing an incubation strategy for Oudtshoorn
- Authors: Petersen, Winifred
- Date: 2011
- Subjects: Business incubators -- South Africa -- Oudshoorn , New business enterprises -- South Africa -- Oudshoorn
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8648 , http://hdl.handle.net/10948/1385 , Business incubators -- South Africa -- Oudshoorn , New business enterprises -- South Africa -- Oudshoorn
- Description: Business incubators, as recognised in their contemporary form, have a history dating back to the 1970s in the United Kingdom and the USA. South Africa is no stranger to this concept of business incubation either: Since the 1980s the Small Business Development Corporation (SBDC) operated business “hives” as clusters of small enterprises. Business incubators are support facilities that empower and stimulate small-entrepreneurial businesses – from the financially vulnerable start-up period, until the time that the fledgling company is ready to operate more autonomously. Business incubators provide, as part of their services, affordable space, financial-management services, sound business advice and other development services. Incubation stimulates the development of small-entrepreneurial businesses and, to this end, helps stimulate the economy. Thus, for South Africa to invest in the development of small growing businesses, is to invest directly in its larger economy and to address its own development challenges like employment-creation, income-generation and the alleviation of poverty. It is in this context that this study discusses the development challenges of one of the rural areas in South Africa, Oudtshoorn, and aims to provide a viable strategy of business incubation for this area, in anticipation that in future lessons can be drawn from this and applied to other rural areas. Oudtshoorn is a town in the Klein Karoo, in the Western Cape Province of South Africa. The strongest sectors in Oudtshoorn’s economy are agriculture and tourism. These two sectors should provide the basis for an empowering business incubator to strengthen and enhance smaller businesses in the town. The study focuses on the development challenges of South Africa and, in particular, a rural town such as Oudtshoorn, the importance of investing in small entrepreneurial businesses so as to strengthen the country’s economy. the nature an significance of a business-incubation strategy for the Oudtshoorn area. Background literature on South Africa’s development challenges was collated as well as information gathered on small-business support and incubation in particular. Literature was retrieved from local institutions as well as national and international sources. Case studies of incubators in South Africa and in other countries were included to enhance the understanding of the importance of business incubation. In addition, the researcher’s close networks with the Oudtshoorn municipality, the local Red Door office and the different role-players in the small-business support sphere allowed for an in-depth assessment of support for such an incubation project and the critical obstacles it may encounter en route.
- Full Text:
- Date Issued: 2011
- Authors: Petersen, Winifred
- Date: 2011
- Subjects: Business incubators -- South Africa -- Oudshoorn , New business enterprises -- South Africa -- Oudshoorn
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8648 , http://hdl.handle.net/10948/1385 , Business incubators -- South Africa -- Oudshoorn , New business enterprises -- South Africa -- Oudshoorn
- Description: Business incubators, as recognised in their contemporary form, have a history dating back to the 1970s in the United Kingdom and the USA. South Africa is no stranger to this concept of business incubation either: Since the 1980s the Small Business Development Corporation (SBDC) operated business “hives” as clusters of small enterprises. Business incubators are support facilities that empower and stimulate small-entrepreneurial businesses – from the financially vulnerable start-up period, until the time that the fledgling company is ready to operate more autonomously. Business incubators provide, as part of their services, affordable space, financial-management services, sound business advice and other development services. Incubation stimulates the development of small-entrepreneurial businesses and, to this end, helps stimulate the economy. Thus, for South Africa to invest in the development of small growing businesses, is to invest directly in its larger economy and to address its own development challenges like employment-creation, income-generation and the alleviation of poverty. It is in this context that this study discusses the development challenges of one of the rural areas in South Africa, Oudtshoorn, and aims to provide a viable strategy of business incubation for this area, in anticipation that in future lessons can be drawn from this and applied to other rural areas. Oudtshoorn is a town in the Klein Karoo, in the Western Cape Province of South Africa. The strongest sectors in Oudtshoorn’s economy are agriculture and tourism. These two sectors should provide the basis for an empowering business incubator to strengthen and enhance smaller businesses in the town. The study focuses on the development challenges of South Africa and, in particular, a rural town such as Oudtshoorn, the importance of investing in small entrepreneurial businesses so as to strengthen the country’s economy. the nature an significance of a business-incubation strategy for the Oudtshoorn area. Background literature on South Africa’s development challenges was collated as well as information gathered on small-business support and incubation in particular. Literature was retrieved from local institutions as well as national and international sources. Case studies of incubators in South Africa and in other countries were included to enhance the understanding of the importance of business incubation. In addition, the researcher’s close networks with the Oudtshoorn municipality, the local Red Door office and the different role-players in the small-business support sphere allowed for an in-depth assessment of support for such an incubation project and the critical obstacles it may encounter en route.
- Full Text:
- Date Issued: 2011
Developing assessment criteria for a sustainable energy sector development project: shale gas exploration in the Karoo
- Authors: Badassey, Jyoti
- Date: 2011
- Subjects: Sustainable development , Economic development -- Sustainability
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9072 , http://hdl.handle.net/10948/d1008405 , Sustainable development , Economic development -- Sustainability
- Description: This research project aims to assess development projects in the energy sector with its focus on the shale gas exploration in the Karoo. The assessment is based on a critical analysis of the concepts and principles of sustainability, complexity and the National Environmental Management Act, using a critical hermeneutics methodology to develop an assessment criterion. Critical hermeneutics is the science and art of interpreting texts, challenging the status quo, its influences and assumptions. Hermeneutics is the reaction to enlightenment fundamentalism, which is an over-reliance on rationality and the scientific method as a primary means of obtaining truth. Hence this research has adopted a triangulation of ideas and concepts derived from sustainability and complexity to find the truth about the sustainability of development projects (Cilliers, 1998; Deleuze & Guattari, 1994; Byrne, 1998). The Central Karoo is situated in the North Eastern part of the Western Province. It is characterised by dry, arid conditions with highly environmentally sensitive land. Central Karoo has the smallest concentration of people in the Western Cape (Van Vuuren, 2008). This research project offers an assessment that will help governments determine the feasibility of energy sector projects since it discusses the impact of exploration for shale gas in the Karoo and explains the process, recommendations and the environmental legislature required for any project to take place in South Africa. Further, it highlights the environmental damage caused by the shale gas exploration as well as the positive economic impact that it could have on the country. For this research, hermeneutics has offered a framework rather than a system; it is a research philosophy that places human experience at the forefront as it honours a variety of interpretations.
- Full Text:
- Date Issued: 2011
- Authors: Badassey, Jyoti
- Date: 2011
- Subjects: Sustainable development , Economic development -- Sustainability
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9072 , http://hdl.handle.net/10948/d1008405 , Sustainable development , Economic development -- Sustainability
- Description: This research project aims to assess development projects in the energy sector with its focus on the shale gas exploration in the Karoo. The assessment is based on a critical analysis of the concepts and principles of sustainability, complexity and the National Environmental Management Act, using a critical hermeneutics methodology to develop an assessment criterion. Critical hermeneutics is the science and art of interpreting texts, challenging the status quo, its influences and assumptions. Hermeneutics is the reaction to enlightenment fundamentalism, which is an over-reliance on rationality and the scientific method as a primary means of obtaining truth. Hence this research has adopted a triangulation of ideas and concepts derived from sustainability and complexity to find the truth about the sustainability of development projects (Cilliers, 1998; Deleuze & Guattari, 1994; Byrne, 1998). The Central Karoo is situated in the North Eastern part of the Western Province. It is characterised by dry, arid conditions with highly environmentally sensitive land. Central Karoo has the smallest concentration of people in the Western Cape (Van Vuuren, 2008). This research project offers an assessment that will help governments determine the feasibility of energy sector projects since it discusses the impact of exploration for shale gas in the Karoo and explains the process, recommendations and the environmental legislature required for any project to take place in South Africa. Further, it highlights the environmental damage caused by the shale gas exploration as well as the positive economic impact that it could have on the country. For this research, hermeneutics has offered a framework rather than a system; it is a research philosophy that places human experience at the forefront as it honours a variety of interpretations.
- Full Text:
- Date Issued: 2011
Developing assessment criteria for successful poverty alleviation with special reference to the Nomzamo Special Care Centre
- Authors: Gidi, Banele Anthony
- Date: 2011
- Subjects: Poverty -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Poverty -- Government policy -- South Africa -- Eastern Cape , Child care services -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9050 , http://hdl.handle.net/10948/1601 , Poverty -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Poverty -- Government policy -- South Africa -- Eastern Cape , Child care services -- South Africa -- Eastern Cape
- Description: While this study is partly theoretical it includes an exploratory case study in which theoretical insights are applied. In the theoretical part of this study, criteria for a successful poverty alleviation project were developed, guided by sustainability theory and complexity theory. It was proposed that researchers could assess existing projects according to these criteria to show where they were successful and where they could improve. The second part of this research consists of a case study, where an actual poverty alleviation project (The Nomzamo Special Care Centre, Peddie, Eastern Cape) was assessed according to the criteria developed in the first part. For this exploratory case study a non-random sample of 9 participants was drawn from the Nomzamo Special Care Centre and other stakeholders in the Ngqushwa Local Municipality in the Eastern Cape. Data was collected using questionnaires, observation and interviews. The results obtained from analysis indicate that project members particularly experience challenges pertaining to financial resources, infrastructure and maintenance. It is recommended that project members receive assistance from the government departments in order for the project to remain sustainable.
- Full Text:
- Date Issued: 2011
- Authors: Gidi, Banele Anthony
- Date: 2011
- Subjects: Poverty -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Poverty -- Government policy -- South Africa -- Eastern Cape , Child care services -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9050 , http://hdl.handle.net/10948/1601 , Poverty -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Poverty -- Government policy -- South Africa -- Eastern Cape , Child care services -- South Africa -- Eastern Cape
- Description: While this study is partly theoretical it includes an exploratory case study in which theoretical insights are applied. In the theoretical part of this study, criteria for a successful poverty alleviation project were developed, guided by sustainability theory and complexity theory. It was proposed that researchers could assess existing projects according to these criteria to show where they were successful and where they could improve. The second part of this research consists of a case study, where an actual poverty alleviation project (The Nomzamo Special Care Centre, Peddie, Eastern Cape) was assessed according to the criteria developed in the first part. For this exploratory case study a non-random sample of 9 participants was drawn from the Nomzamo Special Care Centre and other stakeholders in the Ngqushwa Local Municipality in the Eastern Cape. Data was collected using questionnaires, observation and interviews. The results obtained from analysis indicate that project members particularly experience challenges pertaining to financial resources, infrastructure and maintenance. It is recommended that project members receive assistance from the government departments in order for the project to remain sustainable.
- Full Text:
- Date Issued: 2011
Developing visual images for communicating information aboutantiretroviral side effects to a low-literate population:
- Dowse, Roslind, Ramela, Thato, Barford, Kirsty-Lee, Browne, Sara H
- Authors: Dowse, Roslind , Ramela, Thato , Barford, Kirsty-Lee , Browne, Sara H
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156769 , vital:40048 , https://doi.org/10.2989/16085906.2010.530172
- Description: The side effects of antiretroviral (ARV) therapy are linked to altered quality of life and adherence. Poor adherence has also been associated with low health-literacy skills, with an uninformed patient more likely to make ARV-related decisions that compromise the efficacy of the treatment. Low literacy skills disempower patients in interactions with healthcare providers and preclude the use of existing written patient information materials, which are generally written at a high reading level. Visual images or pictograms used as a counselling tool or included in patient information leaflets have been shown to improve patients’ knowledge, particularly in low-literate groups. The objective of this study was to design visuals or pictograms illustrating various ARV side effects and to evaluate them in a low-literate South African Xhosa population. Core images were generated either from a design workshop or from posed photos or images from textbooks. The research team worked closely with a graphic artist. Initial versions of the images were discussed and assessed in group discussions, and then modified and eventually evaluated quantitatively in individual interviews with 40 participants who each had a maximum of 10 years of schooling.
- Full Text:
- Date Issued: 2011
- Authors: Dowse, Roslind , Ramela, Thato , Barford, Kirsty-Lee , Browne, Sara H
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156769 , vital:40048 , https://doi.org/10.2989/16085906.2010.530172
- Description: The side effects of antiretroviral (ARV) therapy are linked to altered quality of life and adherence. Poor adherence has also been associated with low health-literacy skills, with an uninformed patient more likely to make ARV-related decisions that compromise the efficacy of the treatment. Low literacy skills disempower patients in interactions with healthcare providers and preclude the use of existing written patient information materials, which are generally written at a high reading level. Visual images or pictograms used as a counselling tool or included in patient information leaflets have been shown to improve patients’ knowledge, particularly in low-literate groups. The objective of this study was to design visuals or pictograms illustrating various ARV side effects and to evaluate them in a low-literate South African Xhosa population. Core images were generated either from a design workshop or from posed photos or images from textbooks. The research team worked closely with a graphic artist. Initial versions of the images were discussed and assessed in group discussions, and then modified and eventually evaluated quantitatively in individual interviews with 40 participants who each had a maximum of 10 years of schooling.
- Full Text:
- Date Issued: 2011
Development and testing of liposome encapsulated cyclic dipeptides
- Authors: Kilian, Gareth
- Date: 2011
- Subjects: Peptide antibiotics , Peptide drugs -- Therapeutic use , Peptides -- Synthesis , Antibacterial agents -- Therapeutic use -- Testing , Cyclic peptides , Liposomes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10136 , http://hdl.handle.net/10948/1397 , Peptide antibiotics , Peptide drugs -- Therapeutic use , Peptides -- Synthesis , Antibacterial agents -- Therapeutic use -- Testing , Cyclic peptides , Liposomes
- Description: Cyclic dipeptides have been well characterized for their multitude of biological activities, including antimicrobial and anticancer activities. Cyclo(His-Gly) and cyclo(His-Ala) have also recently been shown to possess significant anticancer activity against a range of cell lines, despite the limitations of these two molecules with respect to their physicochemical properties. Low Log P results in poor cell permeability which can often be problematic for drugs with intracellular mechanisms of action. It can also results in poor biodistribution, and theoretical Log P values for cyclo(His-Gly) and cyclo(His-Ala) were extremely low making them ideal candidates for inclusion into a nanoparticulate drug delivery system. The aim of this study was therefore to formulate and evaluate liposome-encapsulated cyclic dipeptides that increase the tumour-suppressive actions of the cyclic dipeptides, while showing a high degree of specificity for tumour cells. While liposomes are relatively simple to prepare, inter batch variation, low encapsulation and poor stability are often problematic in their production and this has lead to very few liposomal products on the market. This study aimed at using a comprehensive statistical methodology in optimizing liposome formulations encapsulating cyclo(His-Gly) and cyclo(His-Ala). Initial screening of potential factors was conducted using a 25-1 fractional factorial design. This design made use of two levels for each of the five factors and abbreviated the design to minimize runs. Although not much information is provided by these types of designs, the design was sufficient in identifying two critical factors that would be studies further in a more robust design. The two factors selected, based on the screening study, were cholesterol and stearylamine content. These two factors were then used in designing a response surface methodology (RSM) design making use of a central composite rotatable vii design (CCRD) at five levels (-1.5, -1, 0, 1, 1.5) for each factor in order to better understand the design space. Various factors influenced the measured responses of encapsulation efficiency, zeta potential, polydispersity index, cellular uptake and leakage, but most notable were the adverse effects of increasing stearylamine levels on encapsulations efficiency and cholesterol levels on leakage for both cyclo(His-Gly) and cyclo(His-Ala) liposomes. Optimized formulations were derived from the data and prepared. Fair correlation between the predicted and measured responses was obtained. The cytotoxic activity of the encapsulated cyclic dipeptides were assessed against HeLa and MCF-7 cells and found to have limited improvement in activity. However, modification of the polyethylene glycol (PEG) grafted to the liposome surface in order to target folate receptors showed good benefit in significantly decreasing the IC50 values recorded in all cells lines tested, particularly low folate HeLa cells with the lowest IC50 being recorded as 0.0962 mM for folate targeted cyclo(His-Ala). The results therefore indicate that hydrophilic cyclic dipeptides are ideal candidates for inclusion into targeted drug delivery systems such as liposomes. Key words: Liposomes, cyclo(His-Gly), cyclo(His-Ala), cyclic dipeptides, HeLa, MCF-7, folate receptors, factorial design, response surface methodology (RSM), central composite rotatable design (CCRD).
- Full Text:
- Date Issued: 2011
- Authors: Kilian, Gareth
- Date: 2011
- Subjects: Peptide antibiotics , Peptide drugs -- Therapeutic use , Peptides -- Synthesis , Antibacterial agents -- Therapeutic use -- Testing , Cyclic peptides , Liposomes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10136 , http://hdl.handle.net/10948/1397 , Peptide antibiotics , Peptide drugs -- Therapeutic use , Peptides -- Synthesis , Antibacterial agents -- Therapeutic use -- Testing , Cyclic peptides , Liposomes
- Description: Cyclic dipeptides have been well characterized for their multitude of biological activities, including antimicrobial and anticancer activities. Cyclo(His-Gly) and cyclo(His-Ala) have also recently been shown to possess significant anticancer activity against a range of cell lines, despite the limitations of these two molecules with respect to their physicochemical properties. Low Log P results in poor cell permeability which can often be problematic for drugs with intracellular mechanisms of action. It can also results in poor biodistribution, and theoretical Log P values for cyclo(His-Gly) and cyclo(His-Ala) were extremely low making them ideal candidates for inclusion into a nanoparticulate drug delivery system. The aim of this study was therefore to formulate and evaluate liposome-encapsulated cyclic dipeptides that increase the tumour-suppressive actions of the cyclic dipeptides, while showing a high degree of specificity for tumour cells. While liposomes are relatively simple to prepare, inter batch variation, low encapsulation and poor stability are often problematic in their production and this has lead to very few liposomal products on the market. This study aimed at using a comprehensive statistical methodology in optimizing liposome formulations encapsulating cyclo(His-Gly) and cyclo(His-Ala). Initial screening of potential factors was conducted using a 25-1 fractional factorial design. This design made use of two levels for each of the five factors and abbreviated the design to minimize runs. Although not much information is provided by these types of designs, the design was sufficient in identifying two critical factors that would be studies further in a more robust design. The two factors selected, based on the screening study, were cholesterol and stearylamine content. These two factors were then used in designing a response surface methodology (RSM) design making use of a central composite rotatable vii design (CCRD) at five levels (-1.5, -1, 0, 1, 1.5) for each factor in order to better understand the design space. Various factors influenced the measured responses of encapsulation efficiency, zeta potential, polydispersity index, cellular uptake and leakage, but most notable were the adverse effects of increasing stearylamine levels on encapsulations efficiency and cholesterol levels on leakage for both cyclo(His-Gly) and cyclo(His-Ala) liposomes. Optimized formulations were derived from the data and prepared. Fair correlation between the predicted and measured responses was obtained. The cytotoxic activity of the encapsulated cyclic dipeptides were assessed against HeLa and MCF-7 cells and found to have limited improvement in activity. However, modification of the polyethylene glycol (PEG) grafted to the liposome surface in order to target folate receptors showed good benefit in significantly decreasing the IC50 values recorded in all cells lines tested, particularly low folate HeLa cells with the lowest IC50 being recorded as 0.0962 mM for folate targeted cyclo(His-Ala). The results therefore indicate that hydrophilic cyclic dipeptides are ideal candidates for inclusion into targeted drug delivery systems such as liposomes. Key words: Liposomes, cyclo(His-Gly), cyclo(His-Ala), cyclic dipeptides, HeLa, MCF-7, folate receptors, factorial design, response surface methodology (RSM), central composite rotatable design (CCRD).
- Full Text:
- Date Issued: 2011
Development of an ICT road map for eservices in rural areas
- Jere, Norbert R, Thinyane, Mamello, Terzoli, Alfredo
- Authors: Jere, Norbert R , Thinyane, Mamello , Terzoli, Alfredo
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430695 , vital:72709 , https://ieeexplore.ieee.org/abstract/document/6144217
- Description: ICTs, driven by the convergence of computers, telecommunications and traditional media, are crucial for the knowledge-based economy of the future. The rapid technological changes have resulted in different ideas being suggested for the expected ICT applications. As a result, different e-Service applications have being developed as a way to fos-ter ICT developments. However, ICT applications deployed at the mo-ment may not be able to sustain the rural communities in maybe 10 years or more to come. The paper considers the past, analyzes the present and conduct surveys to gain insight into the future. Based on all of this information, the research tries to provide an ICT road map for what is to come. What kind of applications can we develop now to cater for the technological changes, so that the ICT applications developed today would still be compatible with those developed in years to come? The Siyakhula Living Lab (SLL) is used as the case study in this paper and some interviews and literature review are done to get different ide-as on the future of ICTs.
- Full Text:
- Date Issued: 2011
- Authors: Jere, Norbert R , Thinyane, Mamello , Terzoli, Alfredo
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430695 , vital:72709 , https://ieeexplore.ieee.org/abstract/document/6144217
- Description: ICTs, driven by the convergence of computers, telecommunications and traditional media, are crucial for the knowledge-based economy of the future. The rapid technological changes have resulted in different ideas being suggested for the expected ICT applications. As a result, different e-Service applications have being developed as a way to fos-ter ICT developments. However, ICT applications deployed at the mo-ment may not be able to sustain the rural communities in maybe 10 years or more to come. The paper considers the past, analyzes the present and conduct surveys to gain insight into the future. Based on all of this information, the research tries to provide an ICT road map for what is to come. What kind of applications can we develop now to cater for the technological changes, so that the ICT applications developed today would still be compatible with those developed in years to come? The Siyakhula Living Lab (SLL) is used as the case study in this paper and some interviews and literature review are done to get different ide-as on the future of ICTs.
- Full Text:
- Date Issued: 2011
Development of an Interactive Real-Time Negotiation Module for an E-commerce Platform
- Jere, Norbert R, Thinyane, Mamello, Terzoli, Alfredo
- Authors: Jere, Norbert R , Thinyane, Mamello , Terzoli, Alfredo
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430742 , vital:72712 , https://ieeexplore.ieee.org/abstract/document/5954490
- Description: With developments in the Internet and Web-based technologies, dis-tinctions between traditional markets and the global electronic market-place-such as business capital size, are gradually being narrowed down. It is recognized that in the Information Age, e-Commerce is a powerful tool for economic growth of developing countries. While there are indications of e-Commerce patronage among large firms in devel-oping countries, there seems to be little and negligible use of the Inter-net for commerce among small and medium sized firms. However, many of these e-Commerce projects in marginalized areas fail as a re-sult of lack of the required resources to support ICTs. Different ways have been suggested for marketing products online and to create cus-tomer loyalty. This paper discusses a marketing and customer loyalty strategy through a real-time interactive negotiation application, aimed at improving the existing e-Commerce platform. The e-Commerce platform has been deployed as part of the Siyakhula Living Lab ICTD project which is undertaken for the Dwesa community in the Eastern Cape province of South Africa.
- Full Text:
- Date Issued: 2011
- Authors: Jere, Norbert R , Thinyane, Mamello , Terzoli, Alfredo
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430742 , vital:72712 , https://ieeexplore.ieee.org/abstract/document/5954490
- Description: With developments in the Internet and Web-based technologies, dis-tinctions between traditional markets and the global electronic market-place-such as business capital size, are gradually being narrowed down. It is recognized that in the Information Age, e-Commerce is a powerful tool for economic growth of developing countries. While there are indications of e-Commerce patronage among large firms in devel-oping countries, there seems to be little and negligible use of the Inter-net for commerce among small and medium sized firms. However, many of these e-Commerce projects in marginalized areas fail as a re-sult of lack of the required resources to support ICTs. Different ways have been suggested for marketing products online and to create cus-tomer loyalty. This paper discusses a marketing and customer loyalty strategy through a real-time interactive negotiation application, aimed at improving the existing e-Commerce platform. The e-Commerce platform has been deployed as part of the Siyakhula Living Lab ICTD project which is undertaken for the Dwesa community in the Eastern Cape province of South Africa.
- Full Text:
- Date Issued: 2011
Development of an M-Payment system prototype for a marginalized region (Dwesa case study)
- Authors: Mpofu, Handsome C
- Date: 2011
- Subjects: Information technology -- South Africa -- Eastern Cape , Digital divide -- South Africa -- Eastern Cape , Electronic commerce -- South Africa -- Eastern Cape , Mobile communication systems -- South Africa -- Eastern Cape , Home banking services -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11387 , http://hdl.handle.net/10353/458 , Information technology -- South Africa -- Eastern Cape , Digital divide -- South Africa -- Eastern Cape , Electronic commerce -- South Africa -- Eastern Cape , Mobile communication systems -- South Africa -- Eastern Cape , Home banking services -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape
- Description: Wireless technologies, such as Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Fidelity (WiFi), are making it easier to provide the much needed telecommunications infrastructure in marginalized areas worldwide. These technologies enable the rapid deployment of network services as well as their redistribution throughout these marginalized areas. The ability to bring Internet connectivity to previously underserviced and marginalized areas has the potential to leap-frog socio-economic development and improve participation in the global knowledge economy. This study investigated how wireless access technologies, such as WiMAX and WiFi, can be integrated and used to deliver ubiquitous distributed Internet connectivity with increased capillarity in rural areas. The research was undertaken within an ICT for Development (ICT4D) intervention called Siyakhula Living Lab (SLL) which is based in the Eastern Cape province of South Africa. The research further eliminated the accessibility constraints associated with long distances and remoteness from the Digital Access Nodes (DANs) and provided increased penetration in the network in contrast to the traditional Telecentre model which has been used extensively in ICT4D interventions. This was achieved by deploying WiFi hotspots around the DANs and extending the existing SLL WiMAX backbone to increase the network footprint to neighboring communities. The technical result of the research has been the provision of increased capillarity on the network and service redistribution throughout the entire Dwesa community. Consequently, this has given local community members an opportunity to access network services easily and ubiquitously. Finally, the research investigated and presented the benefits of such wireless network deployment configurations on ICT4D activities in marginalized areas.
- Full Text:
- Date Issued: 2011
- Authors: Mpofu, Handsome C
- Date: 2011
- Subjects: Information technology -- South Africa -- Eastern Cape , Digital divide -- South Africa -- Eastern Cape , Electronic commerce -- South Africa -- Eastern Cape , Mobile communication systems -- South Africa -- Eastern Cape , Home banking services -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11387 , http://hdl.handle.net/10353/458 , Information technology -- South Africa -- Eastern Cape , Digital divide -- South Africa -- Eastern Cape , Electronic commerce -- South Africa -- Eastern Cape , Mobile communication systems -- South Africa -- Eastern Cape , Home banking services -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape
- Description: Wireless technologies, such as Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Fidelity (WiFi), are making it easier to provide the much needed telecommunications infrastructure in marginalized areas worldwide. These technologies enable the rapid deployment of network services as well as their redistribution throughout these marginalized areas. The ability to bring Internet connectivity to previously underserviced and marginalized areas has the potential to leap-frog socio-economic development and improve participation in the global knowledge economy. This study investigated how wireless access technologies, such as WiMAX and WiFi, can be integrated and used to deliver ubiquitous distributed Internet connectivity with increased capillarity in rural areas. The research was undertaken within an ICT for Development (ICT4D) intervention called Siyakhula Living Lab (SLL) which is based in the Eastern Cape province of South Africa. The research further eliminated the accessibility constraints associated with long distances and remoteness from the Digital Access Nodes (DANs) and provided increased penetration in the network in contrast to the traditional Telecentre model which has been used extensively in ICT4D interventions. This was achieved by deploying WiFi hotspots around the DANs and extending the existing SLL WiMAX backbone to increase the network footprint to neighboring communities. The technical result of the research has been the provision of increased capillarity on the network and service redistribution throughout the entire Dwesa community. Consequently, this has given local community members an opportunity to access network services easily and ubiquitously. Finally, the research investigated and presented the benefits of such wireless network deployment configurations on ICT4D activities in marginalized areas.
- Full Text:
- Date Issued: 2011
Development of isiXhosa text-to-speech modules to support e-Services in marginalized rural areas
- Authors: Mhlana, Siphe
- Date: 2011
- Subjects: Xhosa language -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Text processing (Computer science) -- South Africa -- Eastern Cape , Literacy -- South Africa -- Eastern Cape , Digital divide -- South Africa -- Eastern Cape , Mobile communication systems -- South Africa -- Eastern Cape , Transmission of texts -- Data processing , Electronic publishing -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11388 , http://hdl.handle.net/10353/495 , Xhosa language -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Text processing (Computer science) -- South Africa -- Eastern Cape , Literacy -- South Africa -- Eastern Cape , Digital divide -- South Africa -- Eastern Cape , Mobile communication systems -- South Africa -- Eastern Cape , Transmission of texts -- Data processing , Electronic publishing -- South Africa -- Eastern Cape
- Description: Information and Communication Technology (ICT) projects are being initiated and deployed in marginalized areas to help improve the standard of living for community members. This has lead to a new field, which is responsible for information processing and knowledge development in rural areas, called Information and Communication Technology for Development (ICT4D). An ICT4D projects has been implemented in a marginalized area called Dwesa; this is a rural area situated in the wild coast of the former homelandof Transkei, in the Eastern Cape Province of South Africa. In this rural community there are e-Service projects which have been developed and deployed to support the already existent ICT infrastructure. Some of these projects include the e-Commerce platform, e-Judiciary service, e-Health and e-Government portal. Although these projects are deployed in this area, community members face a language and literacy barrier because these services are typically accessed through English textual interfaces. This becomes a challenge because their language of communication is isiXhosa and some of the community members are illiterate. Most of the rural areas consist of illiterate people who cannot read and write isiXhosa but can only speak the language. This problem of illiteracy in rural areas affects both the youth and the elderly. This research seeks to design, develop and implement software modules that can be used to convert isiXhosa text into natural sounding isiXhosa speech. Such an application is called a Text-to-Speech (TTS) system. The main objective of this research is to improve ICT4D eServices’ usability through the development of an isiXhosa Text-to-Speech system. This research is undertaken within the context of Siyakhula Living Lab (SLL), an ICT4D intervention towards improving the lives of rural communities of South Africa in an attempt to bridge the digital divide. Thedeveloped TTS modules were subsequently tested to determine their applicability to improve eServices usability. The results show acceptable levels of usability as having produced audio utterances for the isiXhosa Text-To-Speech system for marginalized areas.
- Full Text:
- Date Issued: 2011
- Authors: Mhlana, Siphe
- Date: 2011
- Subjects: Xhosa language -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Text processing (Computer science) -- South Africa -- Eastern Cape , Literacy -- South Africa -- Eastern Cape , Digital divide -- South Africa -- Eastern Cape , Mobile communication systems -- South Africa -- Eastern Cape , Transmission of texts -- Data processing , Electronic publishing -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11388 , http://hdl.handle.net/10353/495 , Xhosa language -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Text processing (Computer science) -- South Africa -- Eastern Cape , Literacy -- South Africa -- Eastern Cape , Digital divide -- South Africa -- Eastern Cape , Mobile communication systems -- South Africa -- Eastern Cape , Transmission of texts -- Data processing , Electronic publishing -- South Africa -- Eastern Cape
- Description: Information and Communication Technology (ICT) projects are being initiated and deployed in marginalized areas to help improve the standard of living for community members. This has lead to a new field, which is responsible for information processing and knowledge development in rural areas, called Information and Communication Technology for Development (ICT4D). An ICT4D projects has been implemented in a marginalized area called Dwesa; this is a rural area situated in the wild coast of the former homelandof Transkei, in the Eastern Cape Province of South Africa. In this rural community there are e-Service projects which have been developed and deployed to support the already existent ICT infrastructure. Some of these projects include the e-Commerce platform, e-Judiciary service, e-Health and e-Government portal. Although these projects are deployed in this area, community members face a language and literacy barrier because these services are typically accessed through English textual interfaces. This becomes a challenge because their language of communication is isiXhosa and some of the community members are illiterate. Most of the rural areas consist of illiterate people who cannot read and write isiXhosa but can only speak the language. This problem of illiteracy in rural areas affects both the youth and the elderly. This research seeks to design, develop and implement software modules that can be used to convert isiXhosa text into natural sounding isiXhosa speech. Such an application is called a Text-to-Speech (TTS) system. The main objective of this research is to improve ICT4D eServices’ usability through the development of an isiXhosa Text-to-Speech system. This research is undertaken within the context of Siyakhula Living Lab (SLL), an ICT4D intervention towards improving the lives of rural communities of South Africa in an attempt to bridge the digital divide. Thedeveloped TTS modules were subsequently tested to determine their applicability to improve eServices usability. The results show acceptable levels of usability as having produced audio utterances for the isiXhosa Text-To-Speech system for marginalized areas.
- Full Text:
- Date Issued: 2011
Development of MgZnO-grown MOCVD for UV Photonic applications
- Authors: Talla, Kharouna
- Date: 2011
- Subjects: Photoluminescence , Photonics , Zinc oxide
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10537 , http://hdl.handle.net/10948/d1012585 , Photoluminescence , Photonics , Zinc oxide
- Description: MgxZn1-xO has emerged as a material of great technological importance. Having a direct energy band gap that is tunable throughout much of the ultraviolet (UV) region of the spectrum from the near-UV (~370 nm) to the deep-UV (~176 nm), this compound is of interest for a variety of optoelectronic devices operating in this part of the electromagnetic spectrum. MgxZn1-xO offers advantages over the more mature compound semiconductor AlGaN which stem mainly from the unusually high exciton binding energy (60 meV in ZnO). In this study the growth of ZnO and MgxZn1-xO thin films using metal organic chemical vapour deposition (MOCVD) is systematically investigated. The films are mainly grown on c-Al2O3 and Si (100) and characterized using various techniques, such as photoluminescence (PL), x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and auger electron spectroscopy (AES). The optical and the structural properties are essentially inspected in order to improve their quality. In this thesis the optimisation of ZnO grown using oxygen gas as a new oxidant in our reactor is investigated. The growth temperature and VI/II ratio are varied in order to find optimum parameters giving high quality layers. The effects of Si (100), Si (111), c- and r-sapphire, glass, GaAs and ZnO substrates on the optical, structural and morphological properties of ZnO thin films grown with tert-butanol (TBOH) is examined. Similar morphologies are observed for all substrates, with the films comprising hexagonal columns having cone shaped ends. The photoluminescence spectra are similar, but the various transitions have different relative intensities. It is clear that the different substrates influence neither the orientation of the films, nor the surface morphology, significantly. The photoluminescence hints at larger stacking fault densities in films grown on silicon and glass, however, as evidenced by stronger basal plane stacking fault-related luminescence at ~3.319 eV in the relevant low temperature photoluminescence spectra. The morphology changes with Mg incorporation, from hexagonal columnar structures to cubic faceted columns. From PL, the full with at half maximum is found to gradually increase with Mg content due to alloy broadening. The deep level emission (DLE) is observed to shift with Mg content. By changing the Mg content, the band gap of MgxZn1-xO film is tuned by ~450 meV, which provides an excellent opportunity for band gap engineering for optoelectronic applications. The c-lattice constant of ZnO (5.205 Å) decreases by only 0.6% when the Mg content reaches x=0.39. The introduction of Mg into ZnO is shown to increase the relative PL intensity of stacking fault-related transitions (at 3.314 eV for ZnO). This becomes the dominant near band edge emission. Using TEM a thin Mg rich layer is observed at the interface between the film and the Si or Al2O3. Temperature dependent PL measurements on layers with low Mg concentration (x=0.05 and 0.1) show that the main bound exciton peak exhibits an “s-shaped” temperature dependence, characteristic of localization in a disordered alloy. The origin of the PL line broadening of MgxZn1-xO (x≤0.04) is also analyzed with respect to alloy broadening, taking into account a random cation distribution and alloy clustering. The influence of various MOCVD growth parameters such as growth temperature and VI/II ratio is studied. Varying the temperature from 280 ˚C to 580 ˚C reveals strong morphological changes and optical degradation of the films. Low (<280 ˚C) and high (>580 ˚C) growth temperatures reduce the Mg incorporation. High VI/II ratios also decrease the Mg incorporation, as evidenced by the red-shift of the donor bound exciton (D°X) line. This is ascribed to a stronger premature reaction between (MeCp)2Mg and the oxidant or a preferential heterogeneous interaction between the Mg and oxygen species on the growth front. For both oxidizing agents (O2 and TBOH), the growth at 420 ˚C and a VI-II ratio of 60 on c-Al2O3 gave optimal quality layers in terms of their optical and structural quality. A comparison of films grown using TBOH and O2 gas as oxidizing agent shows no major difference in terms of Mg incorporation. The effect of annealing, the inclusion of a buffer layer and the influence of growth rate on the properties MgxZn1-xO thin films are also reported.
- Full Text:
- Date Issued: 2011
- Authors: Talla, Kharouna
- Date: 2011
- Subjects: Photoluminescence , Photonics , Zinc oxide
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10537 , http://hdl.handle.net/10948/d1012585 , Photoluminescence , Photonics , Zinc oxide
- Description: MgxZn1-xO has emerged as a material of great technological importance. Having a direct energy band gap that is tunable throughout much of the ultraviolet (UV) region of the spectrum from the near-UV (~370 nm) to the deep-UV (~176 nm), this compound is of interest for a variety of optoelectronic devices operating in this part of the electromagnetic spectrum. MgxZn1-xO offers advantages over the more mature compound semiconductor AlGaN which stem mainly from the unusually high exciton binding energy (60 meV in ZnO). In this study the growth of ZnO and MgxZn1-xO thin films using metal organic chemical vapour deposition (MOCVD) is systematically investigated. The films are mainly grown on c-Al2O3 and Si (100) and characterized using various techniques, such as photoluminescence (PL), x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and auger electron spectroscopy (AES). The optical and the structural properties are essentially inspected in order to improve their quality. In this thesis the optimisation of ZnO grown using oxygen gas as a new oxidant in our reactor is investigated. The growth temperature and VI/II ratio are varied in order to find optimum parameters giving high quality layers. The effects of Si (100), Si (111), c- and r-sapphire, glass, GaAs and ZnO substrates on the optical, structural and morphological properties of ZnO thin films grown with tert-butanol (TBOH) is examined. Similar morphologies are observed for all substrates, with the films comprising hexagonal columns having cone shaped ends. The photoluminescence spectra are similar, but the various transitions have different relative intensities. It is clear that the different substrates influence neither the orientation of the films, nor the surface morphology, significantly. The photoluminescence hints at larger stacking fault densities in films grown on silicon and glass, however, as evidenced by stronger basal plane stacking fault-related luminescence at ~3.319 eV in the relevant low temperature photoluminescence spectra. The morphology changes with Mg incorporation, from hexagonal columnar structures to cubic faceted columns. From PL, the full with at half maximum is found to gradually increase with Mg content due to alloy broadening. The deep level emission (DLE) is observed to shift with Mg content. By changing the Mg content, the band gap of MgxZn1-xO film is tuned by ~450 meV, which provides an excellent opportunity for band gap engineering for optoelectronic applications. The c-lattice constant of ZnO (5.205 Å) decreases by only 0.6% when the Mg content reaches x=0.39. The introduction of Mg into ZnO is shown to increase the relative PL intensity of stacking fault-related transitions (at 3.314 eV for ZnO). This becomes the dominant near band edge emission. Using TEM a thin Mg rich layer is observed at the interface between the film and the Si or Al2O3. Temperature dependent PL measurements on layers with low Mg concentration (x=0.05 and 0.1) show that the main bound exciton peak exhibits an “s-shaped” temperature dependence, characteristic of localization in a disordered alloy. The origin of the PL line broadening of MgxZn1-xO (x≤0.04) is also analyzed with respect to alloy broadening, taking into account a random cation distribution and alloy clustering. The influence of various MOCVD growth parameters such as growth temperature and VI/II ratio is studied. Varying the temperature from 280 ˚C to 580 ˚C reveals strong morphological changes and optical degradation of the films. Low (<280 ˚C) and high (>580 ˚C) growth temperatures reduce the Mg incorporation. High VI/II ratios also decrease the Mg incorporation, as evidenced by the red-shift of the donor bound exciton (D°X) line. This is ascribed to a stronger premature reaction between (MeCp)2Mg and the oxidant or a preferential heterogeneous interaction between the Mg and oxygen species on the growth front. For both oxidizing agents (O2 and TBOH), the growth at 420 ˚C and a VI-II ratio of 60 on c-Al2O3 gave optimal quality layers in terms of their optical and structural quality. A comparison of films grown using TBOH and O2 gas as oxidizing agent shows no major difference in terms of Mg incorporation. The effect of annealing, the inclusion of a buffer layer and the influence of growth rate on the properties MgxZn1-xO thin films are also reported.
- Full Text:
- Date Issued: 2011