An analysis of the certificate of the theory of accounting knowledge and knower structures : a case study of professional knowledge
- Authors: Mkhize, Thandeka Fortunate
- Date: 2015
- Subjects: Accounting -- Study and teaching (Higher) , Dropout behavior, Prediction of , Knowledge, Theory of , Knowledge and learning , Critical realism , Education -- Philosophy , Educational sociology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2057 , http://hdl.handle.net/10962/d1019771
- Description: This research project explores issues around the poor throughput and high dropout rate in the Certificate of the Theory of Accounting (CTA) by focusing on Accounting knowledge as an object of study. The CTA was identified as a serious block in the steps that one needs to go through on the journey to becoming a Chartered Accountant. Having a clear understanding of Accounting knowledge can lead to finding ways that can make the subject more accessible to students from diverse backgrounds. This study contributes to understanding Accounting knowledge at the CTA level with the aim of clearly delineating its legitimate knowledge and knower structures. It answers the following two research questions: • What constitutes legitimate knowledge structures in the CTA? • What constitutes legitimate knower structures in the CTA? Academics from nine universities and representatives of the South African Institute of Chartered Accountants (SAICA) participated in this study. Data was collected through interviews, observation and document analysis. Eighteen CTA lecturers and two members of the SAICA management team were interviewed. Three universities provided documents on their practices, which included learner guides, examination papers, suggested answers, lecture notes, tutorials and other curriculum documents for each of the four CTA subjects. SAICA provided the competency framework and examinable pronouncements. A conference that was jointly hosted by SAICA and International Financial Reporting Standards (IFRS) Foundation was observed. This study used Critical Realism as its ontological underpinnings and Legitimation Code Theory (LCT) as its substantive theory. It used the Specialisation and Autonomy principles of LCT to analyse the data. Specialization establishes the ways agents and discourses within a field are constructed as special, different or unique and thus deserving of distinction and status (Maton, 2014). The principle of Autonomy is concerned with the extent to which the field is self-governing and can do things of its own free-will (Maton, 2004). The study found that the CTA has a hierarchical knowledge structure, which means that when new knowledge is created in Accounting it is integrated into existing knowledge, resulting in coherent and integrated knowledge. CTA also has a hierarchical curriculum structure. While horizontal curriculum structures evolve through the replacement of existing knowledge by new approaches and content, a hierarchical curriculum typically grows through integration and subsumption of new knowledge into pre-existing knowledge and it relies on the acquisition of knowledge developed in previous modules or levels of study.
- Full Text:
- Date Issued: 2015
- Authors: Mkhize, Thandeka Fortunate
- Date: 2015
- Subjects: Accounting -- Study and teaching (Higher) , Dropout behavior, Prediction of , Knowledge, Theory of , Knowledge and learning , Critical realism , Education -- Philosophy , Educational sociology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2057 , http://hdl.handle.net/10962/d1019771
- Description: This research project explores issues around the poor throughput and high dropout rate in the Certificate of the Theory of Accounting (CTA) by focusing on Accounting knowledge as an object of study. The CTA was identified as a serious block in the steps that one needs to go through on the journey to becoming a Chartered Accountant. Having a clear understanding of Accounting knowledge can lead to finding ways that can make the subject more accessible to students from diverse backgrounds. This study contributes to understanding Accounting knowledge at the CTA level with the aim of clearly delineating its legitimate knowledge and knower structures. It answers the following two research questions: • What constitutes legitimate knowledge structures in the CTA? • What constitutes legitimate knower structures in the CTA? Academics from nine universities and representatives of the South African Institute of Chartered Accountants (SAICA) participated in this study. Data was collected through interviews, observation and document analysis. Eighteen CTA lecturers and two members of the SAICA management team were interviewed. Three universities provided documents on their practices, which included learner guides, examination papers, suggested answers, lecture notes, tutorials and other curriculum documents for each of the four CTA subjects. SAICA provided the competency framework and examinable pronouncements. A conference that was jointly hosted by SAICA and International Financial Reporting Standards (IFRS) Foundation was observed. This study used Critical Realism as its ontological underpinnings and Legitimation Code Theory (LCT) as its substantive theory. It used the Specialisation and Autonomy principles of LCT to analyse the data. Specialization establishes the ways agents and discourses within a field are constructed as special, different or unique and thus deserving of distinction and status (Maton, 2014). The principle of Autonomy is concerned with the extent to which the field is self-governing and can do things of its own free-will (Maton, 2004). The study found that the CTA has a hierarchical knowledge structure, which means that when new knowledge is created in Accounting it is integrated into existing knowledge, resulting in coherent and integrated knowledge. CTA also has a hierarchical curriculum structure. While horizontal curriculum structures evolve through the replacement of existing knowledge by new approaches and content, a hierarchical curriculum typically grows through integration and subsumption of new knowledge into pre-existing knowledge and it relies on the acquisition of knowledge developed in previous modules or levels of study.
- Full Text:
- Date Issued: 2015
Re-imagining the nation
- Mngomezulu, Nosipho Sthabiso Thandiwe
- Authors: Mngomezulu, Nosipho Sthabiso Thandiwe
- Date: 2015
- Subjects: Mauritius -- Truth and Justice Commission , Nationalism -- Mauritius , National characteristics, Mauritian , Social justice -- Mauritius , Youth -- Mauritius -- Social conditions , Youth -- Mauritius -- Attitudes , Mauritius -- Politics and government -- 1992- , Ethnicity -- Mauritius
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2124 , http://hdl.handle.net/10962/d1019999
- Description: This thesis examines young people’s constructions of nationhood in Mauritius. In 2008, the Mauritian government instituted a Truth and Justice Commission (TJC), set up to investigate the consequences of slavery and indentured labour. Through the Truth and Justice Commission, the Mauritian government indicated its desire to achieve social justice and national unity. Drawing on developments in studies of national identification practices in the 21st Century, this thesis addresses the question of young Mauritian’s locally and globally informed identification practices and asks how their unofficial narratives of nationhood challenge, or divert, or relate to official state narratives of nationhood. The basis of the study emerges from data collected from 132 participants during fieldwork in multiple fieldsites from May to September 2010 as well as research on Mauritian youth on-line from 2011-2014. The advent of the TJC offers an ideal moment to evaluate the dynamics of post-colonial nation-building and nationhood in a selfstyled multi-cultural state. Nationhood, does not exist apriori to the constructions of narratives of the nation, thus the stories told about the nation, imagine the nation into being. By situating the Truth and Justice Commission and other official state narratives alongside young people’s narratives, I argue that contemporary narratives of nationhood in Mauritius represent an intergenerational struggle to define the meaning of the past in the present and consequently outline the future. Reflecting on the ideas and socio-economic and political processes that induce national consciousness, I argue that young people’s narratives of everyday lived experiences are vital for an interpretation of how nationhood is produced in everyday life. The cultural projects of young people – often rendered as liminal or marginal – offer a critical vantage point from where to read constructions of nationhood. Far from being growing pains or childish games, young people’s identity making practices are what Sherry B. Ortner has called “serious games.” This research suggests that official state government narratives of multicultural nationhood in Mauritius narrowly define national identification along communal loyalties, overlooking the dynamism of interculturality and transnationalism in daily practice on the island. Although communalism and rigid colonial interpretations of ethnicity attempt to police and limit the possibilities of alternative modes of being in Mauritius, young people’s identification practices question, challenge, and threaten to disrupt official discourses of ethnic identification in Mauritius Scholarly investigations of young peoples’ lived experiences of nationhood extend theoretical and methodological frames for the study of nationalized subjects and deepen the understanding of the construction of national consciousness. The construction of nationhood always involves narratives of some sort – scholarship on this area has usually focused on official state narratives from social theorists, state governments, and state elites. I argue for the importance of considering subjectivity and lived experience in conceptions of nationhood. In contemporary post-colonial societies, young people are the numerical majority, however, their voices are seldom represented in theories and narratives of nationhood. Whilst young people may appear in state policies (especially education) and official narratives about the future of the nation, their creative imagining and reimagining of narratives of selfhood is often ignored. I examine how young people increasingly are aware of their transnational connections, through participation in transnational youth cultures, and they are consequently increasingly multi-lingual and multicultural. Fixed notions of ethnic identification and discourses of trauma are not at the forefront of young people’s identification of selfhood, rather their ability to take advantage of their multiply situated identification processes allows them new means to evade and transform these narratives. Their identification of selfhood is characterised by a greater degree of dynamism than previous generations had access to, and thus they do not only identify themselves through officially sanctioned national forms of identification. Loyalty to nationhood is thus less predictable, and young people represent a potential threat to the continuation of older forms of nationhood. While official narratives of nationhood may manipulate ethnic and racial cleavages to secure old loyalties, not all young people are persuaded by these notions
- Full Text:
- Date Issued: 2015
- Authors: Mngomezulu, Nosipho Sthabiso Thandiwe
- Date: 2015
- Subjects: Mauritius -- Truth and Justice Commission , Nationalism -- Mauritius , National characteristics, Mauritian , Social justice -- Mauritius , Youth -- Mauritius -- Social conditions , Youth -- Mauritius -- Attitudes , Mauritius -- Politics and government -- 1992- , Ethnicity -- Mauritius
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2124 , http://hdl.handle.net/10962/d1019999
- Description: This thesis examines young people’s constructions of nationhood in Mauritius. In 2008, the Mauritian government instituted a Truth and Justice Commission (TJC), set up to investigate the consequences of slavery and indentured labour. Through the Truth and Justice Commission, the Mauritian government indicated its desire to achieve social justice and national unity. Drawing on developments in studies of national identification practices in the 21st Century, this thesis addresses the question of young Mauritian’s locally and globally informed identification practices and asks how their unofficial narratives of nationhood challenge, or divert, or relate to official state narratives of nationhood. The basis of the study emerges from data collected from 132 participants during fieldwork in multiple fieldsites from May to September 2010 as well as research on Mauritian youth on-line from 2011-2014. The advent of the TJC offers an ideal moment to evaluate the dynamics of post-colonial nation-building and nationhood in a selfstyled multi-cultural state. Nationhood, does not exist apriori to the constructions of narratives of the nation, thus the stories told about the nation, imagine the nation into being. By situating the Truth and Justice Commission and other official state narratives alongside young people’s narratives, I argue that contemporary narratives of nationhood in Mauritius represent an intergenerational struggle to define the meaning of the past in the present and consequently outline the future. Reflecting on the ideas and socio-economic and political processes that induce national consciousness, I argue that young people’s narratives of everyday lived experiences are vital for an interpretation of how nationhood is produced in everyday life. The cultural projects of young people – often rendered as liminal or marginal – offer a critical vantage point from where to read constructions of nationhood. Far from being growing pains or childish games, young people’s identity making practices are what Sherry B. Ortner has called “serious games.” This research suggests that official state government narratives of multicultural nationhood in Mauritius narrowly define national identification along communal loyalties, overlooking the dynamism of interculturality and transnationalism in daily practice on the island. Although communalism and rigid colonial interpretations of ethnicity attempt to police and limit the possibilities of alternative modes of being in Mauritius, young people’s identification practices question, challenge, and threaten to disrupt official discourses of ethnic identification in Mauritius Scholarly investigations of young peoples’ lived experiences of nationhood extend theoretical and methodological frames for the study of nationalized subjects and deepen the understanding of the construction of national consciousness. The construction of nationhood always involves narratives of some sort – scholarship on this area has usually focused on official state narratives from social theorists, state governments, and state elites. I argue for the importance of considering subjectivity and lived experience in conceptions of nationhood. In contemporary post-colonial societies, young people are the numerical majority, however, their voices are seldom represented in theories and narratives of nationhood. Whilst young people may appear in state policies (especially education) and official narratives about the future of the nation, their creative imagining and reimagining of narratives of selfhood is often ignored. I examine how young people increasingly are aware of their transnational connections, through participation in transnational youth cultures, and they are consequently increasingly multi-lingual and multicultural. Fixed notions of ethnic identification and discourses of trauma are not at the forefront of young people’s identification of selfhood, rather their ability to take advantage of their multiply situated identification processes allows them new means to evade and transform these narratives. Their identification of selfhood is characterised by a greater degree of dynamism than previous generations had access to, and thus they do not only identify themselves through officially sanctioned national forms of identification. Loyalty to nationhood is thus less predictable, and young people represent a potential threat to the continuation of older forms of nationhood. While official narratives of nationhood may manipulate ethnic and racial cleavages to secure old loyalties, not all young people are persuaded by these notions
- Full Text:
- Date Issued: 2015
Water resources availability in the Caledon River basin : past, present and future
- Authors: Mohobane, Thabiso
- Date: 2015
- Subjects: Water-supply -- South Africa -- Caledon River Valley , Climatic changes -- South Africa -- Caledon River Valley , Hydrologic models -- South Africa -- Caledon River Valley , Precipitation forecasting -- South Africa -- Caledon River Valley , Water-supply -- Forecasting , Runoff -- Mathematical models , Evapotranspiration -- South Africa -- Caledon River Valley
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6055 , http://hdl.handle.net/10962/d1019802
- Description: The Caledon River Basin is located on one of the most water-scarce region on the African continent. The water resources of the Caledon River Basin play a pivotal role in socio-economic activities in both Lesotho and South Africa but the basin experiences recurrent severe droughts and frequent water shortages. The Caledon River is mostly used for commercial and subsistence agriculture, industrial and domestic supply. The resources are also important beyond the basin’s boundaries as the water is transferred to the nearby Modder River. The Caledon River is also a significant tributary to the Orange-Senqu Basin, which is shared by five southern African countries. However, the water resources in the basin are under continuous threat as a result of rapidly growing population, economic growth as well as changing climate, amongst others. It is therefore important that the hydrological regime and water resources of the basin are thoroughly evaluated and assessed so that they can be sustainably managed and utilised for maximum economic benefits. Climate change has been identified by the international community as one of the most prominent threats to peace, food security and livelihood and southern Africa as among the most vulnerable regions of the world. Water resources are perceived as a natural resource which will be affected the most by the changing climate conditions. Global warming is expected to bring more severe, prolonged droughts and exacerbate water shortages in this region. The current study is mainly focused on investigating the impacts of climate change on the water resources of the Caledon River Basin. The main objectives of the current study included assessing the past and current hydrological characteristics of the Caledon River Basin under current state of the physical environment, observed climate conditions and estimated water use; detecting any changes in the future rainfall and evaporative demands relative to present conditions and evaluating the impacts of climate on the basin’s hydrological regime and water resources availability for the future climate scenario, 2046-2065. To achieve these objectives the study used observed hydrological, meteorological data sets and the basin’s physical characteristics to establish parameters of the Pitman and WEAP hydrological models. Hydrological modelling is an integral part of hydrological investigations and evaluations. The various sources of uncertainties in the outputs of the climate and hydrological models were identified and quantified, as an integral part of the whole exercise. The 2-step approach of the uncertainty version of the model was used to estimate a range of parameters yielding behavioural natural flow ensembles. This approach uses the regional and local hydrological signals to constrain the model parameter ranges. The estimated parameters were also employed to guide the calibration process of the Water Evaluation And Planning (WEAP) model. The two models incorporated the estimated water uses within the basin to establish the present day flow simulations and they were found to sufficiently simulate the present day flows, as compared to the observed flows. There is an indication therefore, that WEAP can be successfully applied in other regions for hydrological investigations. Possible changes in future climate regime of the basin were evaluated by analysing downscaled temperature and rainfall outputs from a set of 9 climate models. The predictions are based on the A2 greenhouse gases emission scenario which assumes a continuous increase in emission rates. While the climate models agree that temperature, and hence, evapotranspiration will increase in the future, they demonstrate significant disagreement on whether rainfall will decrease or increase and by how much. The disagreement of the GCMs on projected future rainfall constitutes a major uncertainty in the prediction of water resources availability of the basin. This is to the extent that according to 7 out of 9 climate models used, the stream flow in four sub-basins (D21E, D22B, D23D and D23F) in the Caledon River Basin is projected to decrease below the present day flows, while two models (IPSL and MIUB) consistently project enhanced water resource availability in the basin in the future. The differences in the GCM projections highlight the margin of uncertainty involved predicting the future status of water resources in the basin. Such uncertainty should not be ignored and these results can be useful in aiding decision-makers to develop policies that are robust and that encompass all possibilities. In an attempt to reduce the known uncertainties, the study recommends upgrading of the hydrological monitoring network within the Caledon River Basin to facilitate improved hydrological evaluation and management. It also suggests the use of updated climate change data from the newest generation climate models, as well as integrating the findings of the current research into water resources decision making process.
- Full Text:
- Date Issued: 2015
- Authors: Mohobane, Thabiso
- Date: 2015
- Subjects: Water-supply -- South Africa -- Caledon River Valley , Climatic changes -- South Africa -- Caledon River Valley , Hydrologic models -- South Africa -- Caledon River Valley , Precipitation forecasting -- South Africa -- Caledon River Valley , Water-supply -- Forecasting , Runoff -- Mathematical models , Evapotranspiration -- South Africa -- Caledon River Valley
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6055 , http://hdl.handle.net/10962/d1019802
- Description: The Caledon River Basin is located on one of the most water-scarce region on the African continent. The water resources of the Caledon River Basin play a pivotal role in socio-economic activities in both Lesotho and South Africa but the basin experiences recurrent severe droughts and frequent water shortages. The Caledon River is mostly used for commercial and subsistence agriculture, industrial and domestic supply. The resources are also important beyond the basin’s boundaries as the water is transferred to the nearby Modder River. The Caledon River is also a significant tributary to the Orange-Senqu Basin, which is shared by five southern African countries. However, the water resources in the basin are under continuous threat as a result of rapidly growing population, economic growth as well as changing climate, amongst others. It is therefore important that the hydrological regime and water resources of the basin are thoroughly evaluated and assessed so that they can be sustainably managed and utilised for maximum economic benefits. Climate change has been identified by the international community as one of the most prominent threats to peace, food security and livelihood and southern Africa as among the most vulnerable regions of the world. Water resources are perceived as a natural resource which will be affected the most by the changing climate conditions. Global warming is expected to bring more severe, prolonged droughts and exacerbate water shortages in this region. The current study is mainly focused on investigating the impacts of climate change on the water resources of the Caledon River Basin. The main objectives of the current study included assessing the past and current hydrological characteristics of the Caledon River Basin under current state of the physical environment, observed climate conditions and estimated water use; detecting any changes in the future rainfall and evaporative demands relative to present conditions and evaluating the impacts of climate on the basin’s hydrological regime and water resources availability for the future climate scenario, 2046-2065. To achieve these objectives the study used observed hydrological, meteorological data sets and the basin’s physical characteristics to establish parameters of the Pitman and WEAP hydrological models. Hydrological modelling is an integral part of hydrological investigations and evaluations. The various sources of uncertainties in the outputs of the climate and hydrological models were identified and quantified, as an integral part of the whole exercise. The 2-step approach of the uncertainty version of the model was used to estimate a range of parameters yielding behavioural natural flow ensembles. This approach uses the regional and local hydrological signals to constrain the model parameter ranges. The estimated parameters were also employed to guide the calibration process of the Water Evaluation And Planning (WEAP) model. The two models incorporated the estimated water uses within the basin to establish the present day flow simulations and they were found to sufficiently simulate the present day flows, as compared to the observed flows. There is an indication therefore, that WEAP can be successfully applied in other regions for hydrological investigations. Possible changes in future climate regime of the basin were evaluated by analysing downscaled temperature and rainfall outputs from a set of 9 climate models. The predictions are based on the A2 greenhouse gases emission scenario which assumes a continuous increase in emission rates. While the climate models agree that temperature, and hence, evapotranspiration will increase in the future, they demonstrate significant disagreement on whether rainfall will decrease or increase and by how much. The disagreement of the GCMs on projected future rainfall constitutes a major uncertainty in the prediction of water resources availability of the basin. This is to the extent that according to 7 out of 9 climate models used, the stream flow in four sub-basins (D21E, D22B, D23D and D23F) in the Caledon River Basin is projected to decrease below the present day flows, while two models (IPSL and MIUB) consistently project enhanced water resource availability in the basin in the future. The differences in the GCM projections highlight the margin of uncertainty involved predicting the future status of water resources in the basin. Such uncertainty should not be ignored and these results can be useful in aiding decision-makers to develop policies that are robust and that encompass all possibilities. In an attempt to reduce the known uncertainties, the study recommends upgrading of the hydrological monitoring network within the Caledon River Basin to facilitate improved hydrological evaluation and management. It also suggests the use of updated climate change data from the newest generation climate models, as well as integrating the findings of the current research into water resources decision making process.
- Full Text:
- Date Issued: 2015
Characterization of the co-chaperones of Hsp70 and Hsp90 in Trypanosoma brucei and their potential partnerships
- Authors: Mokoena, Fortunate
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54543 , vital:26583
- Description: African Trypanosomiasis, which is caused by Trypanosoma brucei, is one of the crippling agents of social and economic development in Africa. T. brucei cycles between the cold-blooded insect vector, the tsetse fly (Glossina spp), and warm-blooded mammalian hosts. T. brucei, T. cruzi and L. major are mammal infecting kinetoplastid parasites that are collectively referred to as TriTryps. These parasites experience extreme environments as they move between their warm-blooded mammalian hosts and cold-blooded insect vectors which trigger extensive morphological transformations during the life-cycle of the parasite. Molecular chaperones have been implicated in parasite differentiation. TriTryps display significant expansions and diversity in the gene complements encoding molecular chaperones, especially J-proteins. Generally, J-proteins function as co-chaperones of Hsp70s, forming part of vital protein homeostasis processes. Hsp70s show a high degree of conservation, while J-proteins appear to be an extreme case of taxonomic radiation. Although several studies have focused on the molecular and cell biology of Hsp70s in some kinetoplastid parasites, knowledge is still lacking pertaining to J-proteins and their partnerships with Hsp70s. This thesis focused on the classification of kinetoplastid Jproteins into the four types by examining the domain organizations using T. brucei as a guide. The potential partnership of J-proteins and Hsp70s were postulated based on predicted subcellular localization. Kinetoplastid parasites, particularly T. brucei, have evolved an expanded and specialized J-protein machinery, likely to be a consequence of an evolutionary fitness/trait to adapt to diverse environment present in hosts and vectors. These analyses will yield insight into the process of parasite differentiation as well as provide new leads for chemotherapeutic treatments. The presence of the STI1 mediated Hsp90 hetero-complex formation has not been confirmed in T. brucei. To this end, in silico and biochemical techniques were used to characterize the role of TbSTI1, as an adaptor protein of Hsp70 and Hsp90. Through domain architecture analysis, sequence alignments, phylogenetic analysis and three-dimensional structure prediction, TbSTI1 was demonstrated to be the most conserved TPR containing co-chaperone of Hsp70 and Hsp83 in T. brucei and also shown to be highly similar to its eukaryotic homologues. Recombinant TbSTI1 was overproduced and purified in E.coli cells and subsequently shown to associate with TcHsp70 in a concentration dependent manner and associate weakly with TbHsp70.4. TbSTI1 and TbHsp83 were also demonstrated to be expressed and upregulated upon exposure to heat shock at the bloodstream stage of parasite development. In conclusion, this study is the first to report the interaction of TbSTI1 with a chaperone. Interactions between TbSTI1 and Hsp70s were demonstrated and therefore, the formation of the hetero-complex is predicted based the similarity of TbSTI1 to other STI1 proteins.
- Full Text:
- Date Issued: 2015
- Authors: Mokoena, Fortunate
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54543 , vital:26583
- Description: African Trypanosomiasis, which is caused by Trypanosoma brucei, is one of the crippling agents of social and economic development in Africa. T. brucei cycles between the cold-blooded insect vector, the tsetse fly (Glossina spp), and warm-blooded mammalian hosts. T. brucei, T. cruzi and L. major are mammal infecting kinetoplastid parasites that are collectively referred to as TriTryps. These parasites experience extreme environments as they move between their warm-blooded mammalian hosts and cold-blooded insect vectors which trigger extensive morphological transformations during the life-cycle of the parasite. Molecular chaperones have been implicated in parasite differentiation. TriTryps display significant expansions and diversity in the gene complements encoding molecular chaperones, especially J-proteins. Generally, J-proteins function as co-chaperones of Hsp70s, forming part of vital protein homeostasis processes. Hsp70s show a high degree of conservation, while J-proteins appear to be an extreme case of taxonomic radiation. Although several studies have focused on the molecular and cell biology of Hsp70s in some kinetoplastid parasites, knowledge is still lacking pertaining to J-proteins and their partnerships with Hsp70s. This thesis focused on the classification of kinetoplastid Jproteins into the four types by examining the domain organizations using T. brucei as a guide. The potential partnership of J-proteins and Hsp70s were postulated based on predicted subcellular localization. Kinetoplastid parasites, particularly T. brucei, have evolved an expanded and specialized J-protein machinery, likely to be a consequence of an evolutionary fitness/trait to adapt to diverse environment present in hosts and vectors. These analyses will yield insight into the process of parasite differentiation as well as provide new leads for chemotherapeutic treatments. The presence of the STI1 mediated Hsp90 hetero-complex formation has not been confirmed in T. brucei. To this end, in silico and biochemical techniques were used to characterize the role of TbSTI1, as an adaptor protein of Hsp70 and Hsp90. Through domain architecture analysis, sequence alignments, phylogenetic analysis and three-dimensional structure prediction, TbSTI1 was demonstrated to be the most conserved TPR containing co-chaperone of Hsp70 and Hsp83 in T. brucei and also shown to be highly similar to its eukaryotic homologues. Recombinant TbSTI1 was overproduced and purified in E.coli cells and subsequently shown to associate with TcHsp70 in a concentration dependent manner and associate weakly with TbHsp70.4. TbSTI1 and TbHsp83 were also demonstrated to be expressed and upregulated upon exposure to heat shock at the bloodstream stage of parasite development. In conclusion, this study is the first to report the interaction of TbSTI1 with a chaperone. Interactions between TbSTI1 and Hsp70s were demonstrated and therefore, the formation of the hetero-complex is predicted based the similarity of TbSTI1 to other STI1 proteins.
- Full Text:
- Date Issued: 2015
A century of IsiXhosa written poetry and the ideological contest in South Africa
- Authors: Mona, Godfrey Vulindlela
- Date: 2015
- Subjects: Xhosa poetry -- History and criticism , Protest poetry, Xhosa , Ideology and literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3651 , http://hdl.handle.net/10962/d1017892
- Description: The central argument of this inter-disciplinary study is that IsiXhosa written poetry of 1912 – 2012 is a terrain of the struggle between the contending dominant ideologies of Segregation, Apartheid and Charterism (post-Apartheid); and the subordinate/ subaltern ideologies of Africanism, Charterism (pre-democracy), Pan- Africanism, Black Consciousness Movement and other post Apartheid ideologies. The study highlights the mutual relationship between the text and the context by focussing on the ideological contest which manifests itself in both form and structure (i.e. aesthetic ideology) and the content (i.e. authorial ideology) of the poetry of different epochs between 1912 and 2012. The study is located within the framework of Antonio Gramsci’s theory of cultural construction. Gramsci postulates that ideology and culture play a significant role in the process of asserting hegemony. Important concepts that constitute Gramsci’s theory of praxis are: ideology, culture, hegemony, organic intellectuals and both ideological and repressive state apparatuses. The first chapter presents the problem, the objectives, the methodology, and the scope of the study. The second chapter presents Gramsci’s theory of cultural construction and the work of scholars who developed his theory further. The tool that is employed for analysis and interpretation of textual significations of IsiXhosa written poetry is the revolutionary aesthetics, which is proposed by Udenta. The third chapter analyses and interprets literature of the epoch of 1912-1934 and exposes the contest between Segregation and Africanism ideologies. The fourth chapter contextualises and analyses the literature of 1934 – 1948, the second phase of contestation between Segregation and Africanism. The fifth chapter deals with literature of the first and second halves of the Apartheid epoch (1948 - 1973). The Apartheid ideology contested with the Africanist ideology which transformed into the Charterism ideology in 1955. In 1960 Pan-Africanism ideology and in 1969 Black Consciousness Movement ideologies entered the contest. The sixth chapter examines literature of the period 1973 – 1994 which is the second phase of the Apartheid epoch that ends with the “glasnost” period of 1990 - 1994. The seventh chapter studies literature of the democracy period of 1994 – 2012. The eighth chapter is the summary and general conclusion. The illumination of the nexus between culture and ideology during the past century (1912 - 2012) will provide insights that will assist us in addressing the challenges we face during the democracy period, and in the development on Arts and Culture in general, and literature in particular
- Full Text:
- Date Issued: 2015
- Authors: Mona, Godfrey Vulindlela
- Date: 2015
- Subjects: Xhosa poetry -- History and criticism , Protest poetry, Xhosa , Ideology and literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3651 , http://hdl.handle.net/10962/d1017892
- Description: The central argument of this inter-disciplinary study is that IsiXhosa written poetry of 1912 – 2012 is a terrain of the struggle between the contending dominant ideologies of Segregation, Apartheid and Charterism (post-Apartheid); and the subordinate/ subaltern ideologies of Africanism, Charterism (pre-democracy), Pan- Africanism, Black Consciousness Movement and other post Apartheid ideologies. The study highlights the mutual relationship between the text and the context by focussing on the ideological contest which manifests itself in both form and structure (i.e. aesthetic ideology) and the content (i.e. authorial ideology) of the poetry of different epochs between 1912 and 2012. The study is located within the framework of Antonio Gramsci’s theory of cultural construction. Gramsci postulates that ideology and culture play a significant role in the process of asserting hegemony. Important concepts that constitute Gramsci’s theory of praxis are: ideology, culture, hegemony, organic intellectuals and both ideological and repressive state apparatuses. The first chapter presents the problem, the objectives, the methodology, and the scope of the study. The second chapter presents Gramsci’s theory of cultural construction and the work of scholars who developed his theory further. The tool that is employed for analysis and interpretation of textual significations of IsiXhosa written poetry is the revolutionary aesthetics, which is proposed by Udenta. The third chapter analyses and interprets literature of the epoch of 1912-1934 and exposes the contest between Segregation and Africanism ideologies. The fourth chapter contextualises and analyses the literature of 1934 – 1948, the second phase of contestation between Segregation and Africanism. The fifth chapter deals with literature of the first and second halves of the Apartheid epoch (1948 - 1973). The Apartheid ideology contested with the Africanist ideology which transformed into the Charterism ideology in 1955. In 1960 Pan-Africanism ideology and in 1969 Black Consciousness Movement ideologies entered the contest. The sixth chapter examines literature of the period 1973 – 1994 which is the second phase of the Apartheid epoch that ends with the “glasnost” period of 1990 - 1994. The seventh chapter studies literature of the democracy period of 1994 – 2012. The eighth chapter is the summary and general conclusion. The illumination of the nexus between culture and ideology during the past century (1912 - 2012) will provide insights that will assist us in addressing the challenges we face during the democracy period, and in the development on Arts and Culture in general, and literature in particular
- Full Text:
- Date Issued: 2015
Metallophthalocyanine-gold nanoparticle conjugates for photodynamic antimicrobial chemotherapy
- Mthethwa, Thandekile Phakamisiwe
- Authors: Mthethwa, Thandekile Phakamisiwe
- Date: 2015
- Subjects: Nanochemistry , Phthalocyanines , Photochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4543 , http://hdl.handle.net/10962/d1017923
- Description: This thesis presents the synthesis of neutral and cationic metallophthalocyanines and their gold nanoparticles conjugates. The spectroscopic characterization of these compounds is presented herein. The studies presented in this work shows that the conjugation of gold nanoparticles influenced both photophysical and photochemical properties. Gold nanoparticles were found to enhance the singlet oxygen quantum yield while lowering the fluorescence quantum yields. This work also looks at the effect of anisotropic gold nanoparticles such as nanorods and bipyramids on the photophysical behaviour of the metallophthalocyanines. The effect of the size of the gold nanorods was investigated herein. The results show that photophysical and photochemical properties can be influenced by both size and shape of the nanoparticles. Physical characterization about the loading of nanoparticles was also looked into. Parameters such as the surface area, the number of surface atoms, the number of atoms as well as the number of nanoparticles loaded on the surface of the phthalocyanines were studied. The self-assembled monolayers formed by phthalocyanines on gold surfaces were studied using the X-ray photoelectron spectroscopy (XPS). The gold nanoparticles synthesized herein include both organic and water soluble, different capping agents (citrate, tetraammonium bromide (TAOBr) and cetrimethylammonium bromide (CTAB). The concentration of the gold nanoparticles was measured on the inductively coupled plasma (ICP) and their size and shape were obtained from the transmission electron microscopy (TEM) images. A cationic aluminium phthalocyanine and its conjugates were used for photoinactivation of bacteria and fungi. The results show significant reduction and higher activity in the presence of gold nanoparticles, especially nanorods. A small chapter in this work presents an attempted work on the binding of metallothionein protein with protophorphyrin (IX). The pH and concentration dependent binding studies were investigated
- Full Text:
- Date Issued: 2015
- Authors: Mthethwa, Thandekile Phakamisiwe
- Date: 2015
- Subjects: Nanochemistry , Phthalocyanines , Photochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4543 , http://hdl.handle.net/10962/d1017923
- Description: This thesis presents the synthesis of neutral and cationic metallophthalocyanines and their gold nanoparticles conjugates. The spectroscopic characterization of these compounds is presented herein. The studies presented in this work shows that the conjugation of gold nanoparticles influenced both photophysical and photochemical properties. Gold nanoparticles were found to enhance the singlet oxygen quantum yield while lowering the fluorescence quantum yields. This work also looks at the effect of anisotropic gold nanoparticles such as nanorods and bipyramids on the photophysical behaviour of the metallophthalocyanines. The effect of the size of the gold nanorods was investigated herein. The results show that photophysical and photochemical properties can be influenced by both size and shape of the nanoparticles. Physical characterization about the loading of nanoparticles was also looked into. Parameters such as the surface area, the number of surface atoms, the number of atoms as well as the number of nanoparticles loaded on the surface of the phthalocyanines were studied. The self-assembled monolayers formed by phthalocyanines on gold surfaces were studied using the X-ray photoelectron spectroscopy (XPS). The gold nanoparticles synthesized herein include both organic and water soluble, different capping agents (citrate, tetraammonium bromide (TAOBr) and cetrimethylammonium bromide (CTAB). The concentration of the gold nanoparticles was measured on the inductively coupled plasma (ICP) and their size and shape were obtained from the transmission electron microscopy (TEM) images. A cationic aluminium phthalocyanine and its conjugates were used for photoinactivation of bacteria and fungi. The results show significant reduction and higher activity in the presence of gold nanoparticles, especially nanorods. A small chapter in this work presents an attempted work on the binding of metallothionein protein with protophorphyrin (IX). The pH and concentration dependent binding studies were investigated
- Full Text:
- Date Issued: 2015
Synthesis, characterization & application of visible light responsive nitrogen doped Tio2 and copolymer-grafted asymmetric membranes with ozonolysis for water treatment
- Authors: Mungondori, Henry H
- Date: 2015
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11350 , http://hdl.handle.net/10353/d1020257
- Description: The use of titanium dioxide for the photo-catalytic removal of organic, inorganic, and microbial pollutants from natural water and wastewater has been considered a very promising technique. The aim of this study was to prepare nitrogen doped titanium dioxide, immobilize it on asymmetric polymeric membranes of poly (methacrylic acid) grafted onto poly (vinylidene difluoride) (PVDF) blended with poly (acrylonitrile) (PAN), and evaluate the photo-catalytic, antimicrobial, and antifouling properties of the membranes. Nitrogen doped titanium dioxide (N-TiO2) nano-particles were prepared by a low temperature sol gel synthesis technique. The modification of TiO2 with nitrogen allows photo-sensitization of the photo-catalyst towards visible light utilization. The N-TiO2 nano-particles were characterized by fourier transform infrared spectroscopy (FT-IR), scanning x-ray photoelectron spectroscopy (SXPS), X-ray diffraction analysis (XRD), diffuse reflectance spectroscopy (DRS), Brunauer Emmett Teller (BET) surface area analysis, and transmission electron microscopy (TEM). The characterizations revealed the presence of the expected functional groups and confirmed successful doping and that the product was visible light responsive. Novel poly (methacrylic acid) grafted onto poly (vinylidene difluoride)/ poly (acrylonitrile) (PMAA-g-PVDF/ PAN) asymmetric membranes were prepared by the dry-wet phase inversion technique. The poly (methacrylic acid) (PMAA) side chains where grafted onto an activated PVDF backbone by reversible addition fragmentation chain transfer (RAFT) polymerization. The photo-catalytic membranes were generated by blending N-TiO2 with the polymer solution before casting the membranes. The membranes were characterized by FT-IR, nuclear magnetic resonance spectroscopy (NMR), scanning electron microscopy (SEM), and thermo-gravimetric analysis (TGA). FT-IR and NMR analyses confirmed successful grafting of MAA chains onto PVDF while SEM confirmed the successful preparation of membranes with asymmetric structure. The efficacy of the photo-catalytic asymmetric membranes was evaluated on the removal of herbicides from synthetic water. Bentazon was easily degraded while atrazine and paraquat were recalcitrant and proved difficult to degrade. The best results were observed with 3 % N-TiO2-PMAA-g-PVDF/ PAN asymmetric membranes on the photo-degradation of bentazon, atrazine and paraquat in water. Significant enhancement in the photo-degradation of the three herbicides was observed when photo-catalytic degradation was coupled with ozonation. Liquid chromatography-mass spectrometry (LC-MS) analysis confirmed the presence of a degradation by-product during the photo-catalytic degradation of bentazon. The photo-catalytic membranes were also evaluated on the photo-catalytic reduction of heavy metals Pb2+ and Fe3+ in water, and the best results were obtained using 1 % N-TiO2-PMAA-g-PVDF/ PAN and 1 % N-TiO2-PAN asymmetric membranes. All prepared photo-catalytic membranes where capable of completely inactivating E. coli ATCC 8739 within 120 minutes of exposure and inactivation rate increased with increasing N-TiO2 photo-catalyst loading. However, there was an indication from the results obtained that N-TiO2 supported on PMAA-g-PVDF/ PAN showed a higher inactivation rate of E. coli ATCC 8739 compared to N-TiO2-PAN and N-TiO2-PVDF membranes. The 1 % N-TiO2-PMAA-g-PVDF/ PAN membranes gave the highest pure water flux (421.83 L/m2h). This increase (PVDF = 30.50 L/m2h, PAN = 73.85 L/m2h) in pure water flux is owedb to PMAA grafting as well as addition of N-TiO2. These modifications resulted in an increased membrane surface hydrophilicity, which promoted permeation of pure water through the membrane structure. A high bovine serum albumin (BSA) rejection (76.5 %) was noted and can be attributed to steric hindrance brought about by PMAA side chains which prevented the bulky BSA molecules from attaching to the membrane surface for PMAA-g-PVDF/ PAN membranes. However, the supporting porous sub-layer of an asymmetric membrane seemed to play a very important role in the overall permeability of a membrane. PVDF membranes are highly hydrophobic hence they gave a very low pure water flux.
- Full Text:
- Date Issued: 2015
- Authors: Mungondori, Henry H
- Date: 2015
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11350 , http://hdl.handle.net/10353/d1020257
- Description: The use of titanium dioxide for the photo-catalytic removal of organic, inorganic, and microbial pollutants from natural water and wastewater has been considered a very promising technique. The aim of this study was to prepare nitrogen doped titanium dioxide, immobilize it on asymmetric polymeric membranes of poly (methacrylic acid) grafted onto poly (vinylidene difluoride) (PVDF) blended with poly (acrylonitrile) (PAN), and evaluate the photo-catalytic, antimicrobial, and antifouling properties of the membranes. Nitrogen doped titanium dioxide (N-TiO2) nano-particles were prepared by a low temperature sol gel synthesis technique. The modification of TiO2 with nitrogen allows photo-sensitization of the photo-catalyst towards visible light utilization. The N-TiO2 nano-particles were characterized by fourier transform infrared spectroscopy (FT-IR), scanning x-ray photoelectron spectroscopy (SXPS), X-ray diffraction analysis (XRD), diffuse reflectance spectroscopy (DRS), Brunauer Emmett Teller (BET) surface area analysis, and transmission electron microscopy (TEM). The characterizations revealed the presence of the expected functional groups and confirmed successful doping and that the product was visible light responsive. Novel poly (methacrylic acid) grafted onto poly (vinylidene difluoride)/ poly (acrylonitrile) (PMAA-g-PVDF/ PAN) asymmetric membranes were prepared by the dry-wet phase inversion technique. The poly (methacrylic acid) (PMAA) side chains where grafted onto an activated PVDF backbone by reversible addition fragmentation chain transfer (RAFT) polymerization. The photo-catalytic membranes were generated by blending N-TiO2 with the polymer solution before casting the membranes. The membranes were characterized by FT-IR, nuclear magnetic resonance spectroscopy (NMR), scanning electron microscopy (SEM), and thermo-gravimetric analysis (TGA). FT-IR and NMR analyses confirmed successful grafting of MAA chains onto PVDF while SEM confirmed the successful preparation of membranes with asymmetric structure. The efficacy of the photo-catalytic asymmetric membranes was evaluated on the removal of herbicides from synthetic water. Bentazon was easily degraded while atrazine and paraquat were recalcitrant and proved difficult to degrade. The best results were observed with 3 % N-TiO2-PMAA-g-PVDF/ PAN asymmetric membranes on the photo-degradation of bentazon, atrazine and paraquat in water. Significant enhancement in the photo-degradation of the three herbicides was observed when photo-catalytic degradation was coupled with ozonation. Liquid chromatography-mass spectrometry (LC-MS) analysis confirmed the presence of a degradation by-product during the photo-catalytic degradation of bentazon. The photo-catalytic membranes were also evaluated on the photo-catalytic reduction of heavy metals Pb2+ and Fe3+ in water, and the best results were obtained using 1 % N-TiO2-PMAA-g-PVDF/ PAN and 1 % N-TiO2-PAN asymmetric membranes. All prepared photo-catalytic membranes where capable of completely inactivating E. coli ATCC 8739 within 120 minutes of exposure and inactivation rate increased with increasing N-TiO2 photo-catalyst loading. However, there was an indication from the results obtained that N-TiO2 supported on PMAA-g-PVDF/ PAN showed a higher inactivation rate of E. coli ATCC 8739 compared to N-TiO2-PAN and N-TiO2-PVDF membranes. The 1 % N-TiO2-PMAA-g-PVDF/ PAN membranes gave the highest pure water flux (421.83 L/m2h). This increase (PVDF = 30.50 L/m2h, PAN = 73.85 L/m2h) in pure water flux is owedb to PMAA grafting as well as addition of N-TiO2. These modifications resulted in an increased membrane surface hydrophilicity, which promoted permeation of pure water through the membrane structure. A high bovine serum albumin (BSA) rejection (76.5 %) was noted and can be attributed to steric hindrance brought about by PMAA side chains which prevented the bulky BSA molecules from attaching to the membrane surface for PMAA-g-PVDF/ PAN membranes. However, the supporting porous sub-layer of an asymmetric membrane seemed to play a very important role in the overall permeability of a membrane. PVDF membranes are highly hydrophobic hence they gave a very low pure water flux.
- Full Text:
- Date Issued: 2015
The relationship between leadership and organisational effectiveness among indigenous banks in Kenya
- Authors: Muriithi, Samuel Muiruri
- Date: 2015
- Subjects: Leadership -- Kenya , Organizational effectiveness -- Kenya , Transformational leadership -- Kenya , Strategic planning -- Kenya , Community banks -- Kenya , Structural equation modeling , Emotional intelligence
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1208 , http://hdl.handle.net/10962/d1020015
- Description: Defining leadership effectiveness (LE) remains a controversial subject with scholars and researchers disagreeing on a common definition. Most studies term leadership effectiveness as the leaders’ ability to successfully exercise personal influence and abilities in order to accomplish set standards. Such leadership effectiveness was measured using three elements, namely influence, follow commitment and versatility. To be effective, leaders must possess certain competencies and perform specific tasks (independent variables). In this study, three leadership competencies, namely strategic thinking, emotional effectiveness and transformational leadership were examined. Similarly, seven leadership tasks (set organisational direction, develop human capital, build core competencies, create organisational alignment, sustain appropriate organisational culture, manage change and establish balanced organisational control) were identified as essential for the attainment of leadership effectiveness (intervening variable) which, in turn, leads to organisational effectiveness (dependent variable). Given the importance of leadership effectiveness to organisational effectiveness, the purpose of this study was to identify, investigate and empirically test the possible relationship between leadership effectiveness and organisational effectiveness within the Kenyan indigenous banks. To achieve the aim of the study, a survey was undertaken using a structured self-administered questionnaire. The respondents were identified using both probability and non-probability techniques with the survey yielding 257 usable questionnaires that were statistically analysed. The proposed hypothetical relationship between leadership effectiveness and organisational effectiveness was assessed using Structural Equation Modelling (SEM), a multivariate statistical technique. The SEM included Cronbach’s alpha and confirmatory factor analyses to assess the dicriminant reliability and validity of the measuring instrument, and Goodness-of-fit indices. The study findings demonstrated the existence of a strong relationship between leadership competencies, tasks performed and leadership effectiveness which in turn impacts on organisational effectiveness, in this case the overall effectiveness of the Kenyan indigenous banks.
- Full Text:
- Date Issued: 2015
The relationship between leadership and organisational effectiveness among indigenous banks in Kenya
- Authors: Muriithi, Samuel Muiruri
- Date: 2015
- Subjects: Leadership -- Kenya , Organizational effectiveness -- Kenya , Transformational leadership -- Kenya , Strategic planning -- Kenya , Community banks -- Kenya , Structural equation modeling , Emotional intelligence
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1208 , http://hdl.handle.net/10962/d1020015
- Description: Defining leadership effectiveness (LE) remains a controversial subject with scholars and researchers disagreeing on a common definition. Most studies term leadership effectiveness as the leaders’ ability to successfully exercise personal influence and abilities in order to accomplish set standards. Such leadership effectiveness was measured using three elements, namely influence, follow commitment and versatility. To be effective, leaders must possess certain competencies and perform specific tasks (independent variables). In this study, three leadership competencies, namely strategic thinking, emotional effectiveness and transformational leadership were examined. Similarly, seven leadership tasks (set organisational direction, develop human capital, build core competencies, create organisational alignment, sustain appropriate organisational culture, manage change and establish balanced organisational control) were identified as essential for the attainment of leadership effectiveness (intervening variable) which, in turn, leads to organisational effectiveness (dependent variable). Given the importance of leadership effectiveness to organisational effectiveness, the purpose of this study was to identify, investigate and empirically test the possible relationship between leadership effectiveness and organisational effectiveness within the Kenyan indigenous banks. To achieve the aim of the study, a survey was undertaken using a structured self-administered questionnaire. The respondents were identified using both probability and non-probability techniques with the survey yielding 257 usable questionnaires that were statistically analysed. The proposed hypothetical relationship between leadership effectiveness and organisational effectiveness was assessed using Structural Equation Modelling (SEM), a multivariate statistical technique. The SEM included Cronbach’s alpha and confirmatory factor analyses to assess the dicriminant reliability and validity of the measuring instrument, and Goodness-of-fit indices. The study findings demonstrated the existence of a strong relationship between leadership competencies, tasks performed and leadership effectiveness which in turn impacts on organisational effectiveness, in this case the overall effectiveness of the Kenyan indigenous banks.
- Full Text:
- Date Issued: 2015
Graduateness and employability: a case of one polytechnic in Zimbabwe
- Authors: Mutirwara, Miriam
- Date: 2015
- Subjects: Occupational training Employees -- Training -- Zimbabwe College graduates -- Employment -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/6125 , vital:29493
- Description: The study explored the domains of graduateness and employability at one polytechnic in Zimbabwe. The focus was on how instructional delivery strategies and assessment tools could embed domains of graduateness and employer expectations. A phenomenological research approach was used in conducting the study. This qualitative research paradigm allowed the research to take place in a natural setting which enabled a holistic picture and use of an inductive mode of inquiry through the researcher’s immersion in the research setting. Human capital, teaching methods and flexible training models, among others, emerged as major strengths in training. However, these key strengths were marred by unprofessional practices and limited resources. In assessment, proficiency schedules, trade testing and use of external assessors emerged as key strengths. Pertaining to the curriculum, it emerged that on paper, curriculum specifications and design for implementation appeared relevant to the production of a graduate exhibiting attributes of graduateness. It however emerged that there was need to revisit the hidden curriculum, as training was dependent on the availability of resources. The study proposes a framework for promoting graduateness and enhancing employability through creation of mutual partnerships to collectively develop a curriculum that is acceptable to institutions and industry. Moreover, graduateness domains should be enshrined in the curriculum. A need for strategic selection of teaching and assessment methods which promote critical thinking, interaction, decision making and retention of information was identified. Major recommendations are that institutions should align themselves with market demands and technological changes to ensure employability. Institutions should also prepare graduates for transition to the world of work, by rendering adequate preparation through teaming up with industry and the use of appropriate teaching methodology.
- Full Text:
- Date Issued: 2015
- Authors: Mutirwara, Miriam
- Date: 2015
- Subjects: Occupational training Employees -- Training -- Zimbabwe College graduates -- Employment -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/6125 , vital:29493
- Description: The study explored the domains of graduateness and employability at one polytechnic in Zimbabwe. The focus was on how instructional delivery strategies and assessment tools could embed domains of graduateness and employer expectations. A phenomenological research approach was used in conducting the study. This qualitative research paradigm allowed the research to take place in a natural setting which enabled a holistic picture and use of an inductive mode of inquiry through the researcher’s immersion in the research setting. Human capital, teaching methods and flexible training models, among others, emerged as major strengths in training. However, these key strengths were marred by unprofessional practices and limited resources. In assessment, proficiency schedules, trade testing and use of external assessors emerged as key strengths. Pertaining to the curriculum, it emerged that on paper, curriculum specifications and design for implementation appeared relevant to the production of a graduate exhibiting attributes of graduateness. It however emerged that there was need to revisit the hidden curriculum, as training was dependent on the availability of resources. The study proposes a framework for promoting graduateness and enhancing employability through creation of mutual partnerships to collectively develop a curriculum that is acceptable to institutions and industry. Moreover, graduateness domains should be enshrined in the curriculum. A need for strategic selection of teaching and assessment methods which promote critical thinking, interaction, decision making and retention of information was identified. Major recommendations are that institutions should align themselves with market demands and technological changes to ensure employability. Institutions should also prepare graduates for transition to the world of work, by rendering adequate preparation through teaming up with industry and the use of appropriate teaching methodology.
- Full Text:
- Date Issued: 2015
Environmental conflict resolution: a critical analysis of the role of interests and value
- Authors: Mweshi, John
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/55842 , vital:26740
- Description: This thesis intends to contribute to an enhanced understanding of environmental conflicts and their resolution. To accomplish this task the thesis will ascertain the role that value and interests play in environmental conflicts in order to establish an adequate basis upon which they can be resolved. In the process, the thesis will also examine three different approaches, namely, the Standard Approach; the Environmental Impact Assessment (EIA) framework; and the Structured Decision Making (SDM) approach. First, the standard approach is informed by the understanding that focusing on interests instead of human values makes the resolution of conflicts more tractable. In contrast, this thesis argues that an exclusive focus on interests, in the context of environmental conflict resolution, is inadequate in some important respects because there are other factors to be considered such as the environmental impacts at the root of the conflict. Second, the thesis examines the focus on impacts that characterises EIAs. It argues that this approach remedies the limitations of the standard approach insofar as impacts are understood in terms of object value. However, the EIA approach does not provide much guidance on how to deal with conflicting human values. Third, taking into account the fact that the standard approach does not address the question of object value, while the EIA addresses object value but does not deal directly with human values, the thesis examines the SDM approach to environmental risk decisions. The thesis argues that while the SDM approach claims to deal with conflicts involving human values head-on, it does not provide a viable alternative in terms of environmental conflict resolution. This is because it fails to recognise the key distinction between human values and object value despite acknowledging the presence of multiple value dimensions as a major obstacle to value trade-offs and therefore to the resolution of value conflicts. Finally, the thesis recommends an adequate basis upon which environmental conflicts can be resolved.
- Full Text:
- Date Issued: 2015
- Authors: Mweshi, John
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/55842 , vital:26740
- Description: This thesis intends to contribute to an enhanced understanding of environmental conflicts and their resolution. To accomplish this task the thesis will ascertain the role that value and interests play in environmental conflicts in order to establish an adequate basis upon which they can be resolved. In the process, the thesis will also examine three different approaches, namely, the Standard Approach; the Environmental Impact Assessment (EIA) framework; and the Structured Decision Making (SDM) approach. First, the standard approach is informed by the understanding that focusing on interests instead of human values makes the resolution of conflicts more tractable. In contrast, this thesis argues that an exclusive focus on interests, in the context of environmental conflict resolution, is inadequate in some important respects because there are other factors to be considered such as the environmental impacts at the root of the conflict. Second, the thesis examines the focus on impacts that characterises EIAs. It argues that this approach remedies the limitations of the standard approach insofar as impacts are understood in terms of object value. However, the EIA approach does not provide much guidance on how to deal with conflicting human values. Third, taking into account the fact that the standard approach does not address the question of object value, while the EIA addresses object value but does not deal directly with human values, the thesis examines the SDM approach to environmental risk decisions. The thesis argues that while the SDM approach claims to deal with conflicts involving human values head-on, it does not provide a viable alternative in terms of environmental conflict resolution. This is because it fails to recognise the key distinction between human values and object value despite acknowledging the presence of multiple value dimensions as a major obstacle to value trade-offs and therefore to the resolution of value conflicts. Finally, the thesis recommends an adequate basis upon which environmental conflicts can be resolved.
- Full Text:
- Date Issued: 2015
An assessment of e-procurement in the Eastern Cape provincial government
- Myataza, Nosiphendule Mlamli
- Authors: Myataza, Nosiphendule Mlamli
- Date: 2015
- Subjects: Government purchasing -- South Africa -- Eastern Cape Electronic commerce -- South Africa -- Eastern Cape Public administration -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Public Administration)
- Identifier: http://hdl.handle.net/10353/1601 , vital:27483
- Description: Public procurement is the government activity most vulnerable to corruption. Lack of transparency and accountability are recognised as a major threat to integrity in public procurement. Repeated findings by the Auditor- General(SA) on poor document management and lack of compliance with the Public Finance Management Act ( No1 of 1999) by the SCM units in departments of the Eastern Cape Provincial Administration necessitates the use of e-procurement for purposes of accountability and proper documentation of transactions. The study assessed the current status of e-procurement in the Eastern Cape Provincial government. This entailed an overview of IFMS, identifying its implementation and shortcomings. Also reviewed was implementation of the Logistical Information System ( LOGIS) in the Eastern Cape Provincial Administration (Department of Health) as its e-procurement platform, as well as e-procurement at the Department of Social development and Special Programmes .The status of government suppliers’ internet connectivity was also assessed.
- Full Text:
- Date Issued: 2015
- Authors: Myataza, Nosiphendule Mlamli
- Date: 2015
- Subjects: Government purchasing -- South Africa -- Eastern Cape Electronic commerce -- South Africa -- Eastern Cape Public administration -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Public Administration)
- Identifier: http://hdl.handle.net/10353/1601 , vital:27483
- Description: Public procurement is the government activity most vulnerable to corruption. Lack of transparency and accountability are recognised as a major threat to integrity in public procurement. Repeated findings by the Auditor- General(SA) on poor document management and lack of compliance with the Public Finance Management Act ( No1 of 1999) by the SCM units in departments of the Eastern Cape Provincial Administration necessitates the use of e-procurement for purposes of accountability and proper documentation of transactions. The study assessed the current status of e-procurement in the Eastern Cape Provincial government. This entailed an overview of IFMS, identifying its implementation and shortcomings. Also reviewed was implementation of the Logistical Information System ( LOGIS) in the Eastern Cape Provincial Administration (Department of Health) as its e-procurement platform, as well as e-procurement at the Department of Social development and Special Programmes .The status of government suppliers’ internet connectivity was also assessed.
- Full Text:
- Date Issued: 2015
Modification and application of the decentralised wastewater treatment technology for greywater treatment to reduce water needs
- Authors: Ngqwala, Nosiphiwe P
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/103714 , vital:32290
- Description: Expected release date-April 2017
- Full Text: false
- Date Issued: 2015
- Authors: Ngqwala, Nosiphiwe P
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/103714 , vital:32290
- Description: Expected release date-April 2017
- Full Text: false
- Date Issued: 2015
Monetary policy transparency in Sub-Saharan Africa evidence and lessons
- Nhavira, John Davison Gondwe
- Authors: Nhavira, John Davison Gondwe
- Date: 2015
- Subjects: Monetary policy -- Africa, Sub-Saharan , Banks and banking, Central -- Africa, Sub-Saharan
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: http://hdl.handle.net/10948/5262 , vital:20827
- Description: This research deals with achieving and maintaining price stability in Sub-Saharan Africa (SSA) through the practice of monetary-policy transparency (MPT). On the one hand, MPT refers to a monetary strategy whereby the central bank is insulated from political influence and made accountable to society through disclosure of its policies, procedures, economic models, data and forecasts, operations and political practices (such as objectives, personnel independence, and the like). On the other hand, price stability refers to achieving and maintaining low and stable levels of inflation conducive for long-term planning and poverty alleviation. The primary objective of this research was to investigate MPT in SSA as it represents a powerful means whereby economic agents’ expectations may be coordinated and managed by the central bank to achieve its societal, objective function of low inflation. The empirical evidence shows that, first, a dependent central bank is more likely to slip into hyperinflation. Second, a SADC (2008) model central bank law is not independent enough to be used as a benchmark for any central bank or as a charter for a regional central bank. Third, the degree of central bank independence in SSA is relatively lower than that in industrialised economies. Fourth, the determinants of MPT in SSA are trade openness, and financial depth that are important factors influencing policy-makers to adopt monetary-policy transparency. Fifth, MPT is associated with a decline in the inflation rate. Sixth, MPT had no significant effect on economic output, whilst trade openness was positively associated with real GDP.
- Full Text:
- Date Issued: 2015
- Authors: Nhavira, John Davison Gondwe
- Date: 2015
- Subjects: Monetary policy -- Africa, Sub-Saharan , Banks and banking, Central -- Africa, Sub-Saharan
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: http://hdl.handle.net/10948/5262 , vital:20827
- Description: This research deals with achieving and maintaining price stability in Sub-Saharan Africa (SSA) through the practice of monetary-policy transparency (MPT). On the one hand, MPT refers to a monetary strategy whereby the central bank is insulated from political influence and made accountable to society through disclosure of its policies, procedures, economic models, data and forecasts, operations and political practices (such as objectives, personnel independence, and the like). On the other hand, price stability refers to achieving and maintaining low and stable levels of inflation conducive for long-term planning and poverty alleviation. The primary objective of this research was to investigate MPT in SSA as it represents a powerful means whereby economic agents’ expectations may be coordinated and managed by the central bank to achieve its societal, objective function of low inflation. The empirical evidence shows that, first, a dependent central bank is more likely to slip into hyperinflation. Second, a SADC (2008) model central bank law is not independent enough to be used as a benchmark for any central bank or as a charter for a regional central bank. Third, the degree of central bank independence in SSA is relatively lower than that in industrialised economies. Fourth, the determinants of MPT in SSA are trade openness, and financial depth that are important factors influencing policy-makers to adopt monetary-policy transparency. Fifth, MPT is associated with a decline in the inflation rate. Sixth, MPT had no significant effect on economic output, whilst trade openness was positively associated with real GDP.
- Full Text:
- Date Issued: 2015
An investigation into English second language competence and performance of Shona and Ndebele first lanuage learners
- Authors: Nhongo, Raphael
- Date: 2015
- Subjects: Applied linguistics -- South Africa , Language and languages -- Study and teaching -- South Africa , Multilingual education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/12216 , vital:39198
- Description: The thrust of the study was to investigate the common ESL practices towards proficiency amongst O‟ level learners who are L1 speakers of either Shona or Ndebele and who are from either a rural or an urban setting. The aim of the study was to scrutinize how a learner‟s first language and the rural and urban environment influence ESL proficiency. The aim was to establish how rural and urban settings condition ESL proficiency and how ESL proficiency differs between these two settings. The other aim of the study was to establish the strategies that are used by teachers and learners in ESL teaching and learning and also to evaluate the effectiveness of such strategies. The study was qualitative in nature although a limited quantitative design was employed in the presentation of frequency tables. The study used a case study design. The information that was used in this study was gathered through the use of proficiency tests that were administered to forty O‟ level learners and through content analysis of learners‟ essays which were extracted from their essay exercise books. Sixteen O‟ level English language teachers, six English language examiners, one subject manager of English language and two curriculum developers were interviewed. The secondary data also played an important role in the study. The results of the study showed that teachers and learners use a number of strategies in the teaching and learning of ESL of which some of the strategies that they use have previously not been documented by other L2 researchers. It was also realized that learners in rural areas are at a disadvantage as compared to those in rural schools and such challenges include lack of exposure, inadequate reading materials, faulty instruction, unavailability of libraries and some other social issues. The major conclusion that was made in this study was that ESL learning and teaching strategies are of crucial importance to competence and performance in ESL proficiency.
- Full Text:
- Date Issued: 2015
- Authors: Nhongo, Raphael
- Date: 2015
- Subjects: Applied linguistics -- South Africa , Language and languages -- Study and teaching -- South Africa , Multilingual education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/12216 , vital:39198
- Description: The thrust of the study was to investigate the common ESL practices towards proficiency amongst O‟ level learners who are L1 speakers of either Shona or Ndebele and who are from either a rural or an urban setting. The aim of the study was to scrutinize how a learner‟s first language and the rural and urban environment influence ESL proficiency. The aim was to establish how rural and urban settings condition ESL proficiency and how ESL proficiency differs between these two settings. The other aim of the study was to establish the strategies that are used by teachers and learners in ESL teaching and learning and also to evaluate the effectiveness of such strategies. The study was qualitative in nature although a limited quantitative design was employed in the presentation of frequency tables. The study used a case study design. The information that was used in this study was gathered through the use of proficiency tests that were administered to forty O‟ level learners and through content analysis of learners‟ essays which were extracted from their essay exercise books. Sixteen O‟ level English language teachers, six English language examiners, one subject manager of English language and two curriculum developers were interviewed. The secondary data also played an important role in the study. The results of the study showed that teachers and learners use a number of strategies in the teaching and learning of ESL of which some of the strategies that they use have previously not been documented by other L2 researchers. It was also realized that learners in rural areas are at a disadvantage as compared to those in rural schools and such challenges include lack of exposure, inadequate reading materials, faulty instruction, unavailability of libraries and some other social issues. The major conclusion that was made in this study was that ESL learning and teaching strategies are of crucial importance to competence and performance in ESL proficiency.
- Full Text:
- Date Issued: 2015
Going green: the impact of integrated sustainability reporting within JSE companies
- Authors: Nkosi, Jabulani Elias
- Date: 2015
- Subjects: Sustainable development , Environmental policy
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/9129 , vital:26467
- Description: The world is threatened by the possibility of an irreversible catastrophe that many would blame on the environmental impact of the present lifestyle, the results of which are climate change or global warming. This is clearly unacceptable to both present and future generations. If going green really means changing the way we live and pursuing knowledge and practices that can lead to more environmentally friendly and socio-ecologically responsible decisions, it is time to protect the environment and sustain its natural resources for current and future generations. Integrated sustainability reporting should be viewed as a vehicle to accomplish this global agenda of going green beyond mere legal requirements. The purpose of this study was to investigate the impact of integrated sustainability reporting (ISR) on achieving green business status within JSE listed companies. To achieve the purpose, an in-depth literature study and empirical research were undertaken using a triangulation method. After a detailed descriptive and content analysis of the collected primary and secondary data, the study found the following: Most of the JSE listed corporations’ integrated reports are not utilising the CSR, GRI guidelines and voluntary standards as effective tools to drive the process of green sustainable business. Some of the JSE listed organisations are treating financial and non-financial matters as separate issues in their integrated reports; The ISR has no impact in terms of using the NEMA framework in driving the process of green sustainable business in the JSE listed organisations; Most of the JSE listed organisations were fully aware of ecological sustainability as a pillar to drive the process of green sustainable business. They treat this pillar of sustainable development as a separate entity from socio-economic developmental issues. Most of the JSE listed corporations adhere to all the bylaws and regulations of ecological sustainability within their required certification of ISO 14001 standards in order to remain effectively certified by the auditing authority. Some integrated reports indicated much support for staff in terms of health, educational activities, labour laws and programmes that advance the socio-economic aspects of human beings; The study has found that the social pillar of sustainability is mostly supported by JSE listed organisations in South Africa - to the level of the requirements of labour relations legislation. It is not integrated with sustainability policies beyond the statutory requirements; It was further noticed in this study that integrated sustainability reports, based on the Global Reporting Initiative (GRI) principles and the King III reporting guidelines, disclose outcomes and results regarding the JSE listed organisations’ obligations, strategy and management approach which occurred within the reporting period. To address the above-listed findings, the researcher recommended that the JSE listed organisations integrate the NEMA, EMS, CSR, GRI and King III guidelines in their integrated sustainability reporting, in order to produce an effective sustainable green business in South Africa that is ecologically accountable and socio-economically supportive to all multi-stakeholders. The government and non-governmental organisations are the key players to drive the process of going green using the ISR. The government needs more structured policies and regulations that will support the National Development Plan in the pursuit of green economy in the form of grants and incentives that are beyond the present status quo.
- Full Text:
- Date Issued: 2015
- Authors: Nkosi, Jabulani Elias
- Date: 2015
- Subjects: Sustainable development , Environmental policy
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/9129 , vital:26467
- Description: The world is threatened by the possibility of an irreversible catastrophe that many would blame on the environmental impact of the present lifestyle, the results of which are climate change or global warming. This is clearly unacceptable to both present and future generations. If going green really means changing the way we live and pursuing knowledge and practices that can lead to more environmentally friendly and socio-ecologically responsible decisions, it is time to protect the environment and sustain its natural resources for current and future generations. Integrated sustainability reporting should be viewed as a vehicle to accomplish this global agenda of going green beyond mere legal requirements. The purpose of this study was to investigate the impact of integrated sustainability reporting (ISR) on achieving green business status within JSE listed companies. To achieve the purpose, an in-depth literature study and empirical research were undertaken using a triangulation method. After a detailed descriptive and content analysis of the collected primary and secondary data, the study found the following: Most of the JSE listed corporations’ integrated reports are not utilising the CSR, GRI guidelines and voluntary standards as effective tools to drive the process of green sustainable business. Some of the JSE listed organisations are treating financial and non-financial matters as separate issues in their integrated reports; The ISR has no impact in terms of using the NEMA framework in driving the process of green sustainable business in the JSE listed organisations; Most of the JSE listed organisations were fully aware of ecological sustainability as a pillar to drive the process of green sustainable business. They treat this pillar of sustainable development as a separate entity from socio-economic developmental issues. Most of the JSE listed corporations adhere to all the bylaws and regulations of ecological sustainability within their required certification of ISO 14001 standards in order to remain effectively certified by the auditing authority. Some integrated reports indicated much support for staff in terms of health, educational activities, labour laws and programmes that advance the socio-economic aspects of human beings; The study has found that the social pillar of sustainability is mostly supported by JSE listed organisations in South Africa - to the level of the requirements of labour relations legislation. It is not integrated with sustainability policies beyond the statutory requirements; It was further noticed in this study that integrated sustainability reports, based on the Global Reporting Initiative (GRI) principles and the King III reporting guidelines, disclose outcomes and results regarding the JSE listed organisations’ obligations, strategy and management approach which occurred within the reporting period. To address the above-listed findings, the researcher recommended that the JSE listed organisations integrate the NEMA, EMS, CSR, GRI and King III guidelines in their integrated sustainability reporting, in order to produce an effective sustainable green business in South Africa that is ecologically accountable and socio-economically supportive to all multi-stakeholders. The government and non-governmental organisations are the key players to drive the process of going green using the ISR. The government needs more structured policies and regulations that will support the National Development Plan in the pursuit of green economy in the form of grants and incentives that are beyond the present status quo.
- Full Text:
- Date Issued: 2015
An investigation of the effect of co-solvents on the hydrothermal liquefaction of microalgae biomass
- Authors: Nongauza, Sinethemba Aubrey
- Date: 2015
- Subjects: Biomass chemicals Microalgae -- Biotechnology , Supercritical fluids Solvents
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/21667 , vital:29731
- Description: The study introduces and demonstrates the viability of the continuous flow reactor (CFR) system for the production of bio-crude oil (BCO) from wet microalgae. Preliminary experiments conducted in the CFR system in hot compressed water (HCW) were successful in converting wet microalgae into liquid BCO. However, the synthesis and aggregation of high boiling point (HBP) components of BCO and the accumulation of char in the tubular piping of CFR system were identified as the limiting factor to the viability of the system. The aggregation of HBP components and the accumulation of char result to system blockage which prevents the continuous flow of the liquefaction product mixture in the CFR system. Inhibiting the reactions leading to the formation of HBP components and char will improve the performance of the CFR system. Therefore, the study seeks to incorporate co-solvents in the liquefaction reaction media in an attempt to inhibit or minimize the prevalence of HBP components of BCO. As such, different co-solvents were screened for their influence on improving the quality of BCO with respect to its boiling point profile (BPP), initial and final boiling point, as well as the amount of char recovered from each experiment. Only one co-solvent was chosen for further exploration in the CFR system. Batch liquefaction reactor’s (BLR) made up of stainless steel were used to carry out the co-solvent screening experiments. These experiments were carried out at a constant temperature (280 °C), pressure (75 bar), and co-solvent concentration (10 wt.%), at varying residence times. Solvent extraction with dichloromethane (DCM) was performed on the liquefaction product mixture to separate the products, viz. BCO, char and water soluble components. The extracted BCO was analysed through simulated distillation (SimDis) to obtain the BPP. The BPP properties of the BCO samples, from different liquefaction media, and the amount of char recovered were highly influenced by the addition of a co-solvent. The final boiling point (FBP) of tetralin, heptane, and n-octanol BCO products were significantly reduced to below 500 °C for all tested residence times except at 20 minutes. The residence time also proved to be influential in the processing of wet microalgae. n-Octanol was selected as the optimal performing co-solvent and was used for the continuous liquefaction of wet microalgae in the CFR system. The CFR system was modified by adding a co-solvent feed line into the continuous system since n-octanol was insoluble in water. The n-octanol pump was set at different flow rates, 0.2, 0.3, and 0.4 g/min, which resulted in a concentration of about 10 wt.% in the reactor feed. The concentration of n-octanol had a significant influence on the BPP of BCO components. The FBP’s were reduced with an increase in n-octanol concentration. The initial boiling point (IBP) of n-octanol BCO was increased to just above 100 °C which was required for the stability of the BCO product. The components of BCO were identified by GCMS. n-Octanol also proved to affect the composition of the BCO with respect to its components. HCW BCO components were significantly different from those identified from n-octanol BCO. A second co-solvent (tetralin) was used to prove whether the difference on the components of BCO was affected by n-octanol. The results proved that indeed the addition of different solvents in liquefaction reaction media favours the formation of different components. The amount of char formed was also reduced when using a co-solvent. A decrease in the oxygen/nitrogen compounds was also observed in the presence of a co-solvent, thus improving BCO properties.
- Full Text:
- Date Issued: 2015
An investigation of the effect of co-solvents on the hydrothermal liquefaction of microalgae biomass
- Authors: Nongauza, Sinethemba Aubrey
- Date: 2015
- Subjects: Biomass chemicals Microalgae -- Biotechnology , Supercritical fluids Solvents
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/21667 , vital:29731
- Description: The study introduces and demonstrates the viability of the continuous flow reactor (CFR) system for the production of bio-crude oil (BCO) from wet microalgae. Preliminary experiments conducted in the CFR system in hot compressed water (HCW) were successful in converting wet microalgae into liquid BCO. However, the synthesis and aggregation of high boiling point (HBP) components of BCO and the accumulation of char in the tubular piping of CFR system were identified as the limiting factor to the viability of the system. The aggregation of HBP components and the accumulation of char result to system blockage which prevents the continuous flow of the liquefaction product mixture in the CFR system. Inhibiting the reactions leading to the formation of HBP components and char will improve the performance of the CFR system. Therefore, the study seeks to incorporate co-solvents in the liquefaction reaction media in an attempt to inhibit or minimize the prevalence of HBP components of BCO. As such, different co-solvents were screened for their influence on improving the quality of BCO with respect to its boiling point profile (BPP), initial and final boiling point, as well as the amount of char recovered from each experiment. Only one co-solvent was chosen for further exploration in the CFR system. Batch liquefaction reactor’s (BLR) made up of stainless steel were used to carry out the co-solvent screening experiments. These experiments were carried out at a constant temperature (280 °C), pressure (75 bar), and co-solvent concentration (10 wt.%), at varying residence times. Solvent extraction with dichloromethane (DCM) was performed on the liquefaction product mixture to separate the products, viz. BCO, char and water soluble components. The extracted BCO was analysed through simulated distillation (SimDis) to obtain the BPP. The BPP properties of the BCO samples, from different liquefaction media, and the amount of char recovered were highly influenced by the addition of a co-solvent. The final boiling point (FBP) of tetralin, heptane, and n-octanol BCO products were significantly reduced to below 500 °C for all tested residence times except at 20 minutes. The residence time also proved to be influential in the processing of wet microalgae. n-Octanol was selected as the optimal performing co-solvent and was used for the continuous liquefaction of wet microalgae in the CFR system. The CFR system was modified by adding a co-solvent feed line into the continuous system since n-octanol was insoluble in water. The n-octanol pump was set at different flow rates, 0.2, 0.3, and 0.4 g/min, which resulted in a concentration of about 10 wt.% in the reactor feed. The concentration of n-octanol had a significant influence on the BPP of BCO components. The FBP’s were reduced with an increase in n-octanol concentration. The initial boiling point (IBP) of n-octanol BCO was increased to just above 100 °C which was required for the stability of the BCO product. The components of BCO were identified by GCMS. n-Octanol also proved to affect the composition of the BCO with respect to its components. HCW BCO components were significantly different from those identified from n-octanol BCO. A second co-solvent (tetralin) was used to prove whether the difference on the components of BCO was affected by n-octanol. The results proved that indeed the addition of different solvents in liquefaction reaction media favours the formation of different components. The amount of char formed was also reduced when using a co-solvent. A decrease in the oxygen/nitrogen compounds was also observed in the presence of a co-solvent, thus improving BCO properties.
- Full Text:
- Date Issued: 2015
Stability of the money demand function and monetary inflation in the East African community
- Authors: Nsabimana, Adelit
- Date: 2015
- Subjects: Monetary policy -- Africa, East , Inflation (Finance) -- Africa, East , Equilibrium (Economics)
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: http://hdl.handle.net/10948/9163 , vital:26470
- Description: This research attempts to evaluate the stability of money demand functions and estimate monetary inflation models in the East African Community (EAC), using quarterly aggregate data that range from 2000Q1 to 2012Q3. We used Johansen co-integration analysis to estimate and analyse the stability of the M3 money demand model for each country member of the EAC. From this estimation, we derived a country-specific measure of money overhang. We compared its forecasting power of future inflation with that of money stock growth, and money stock available in the economy. Regarding country-specific money demand functions, with the exception of Uganda, we identified a reasonable and stable country-specific M3 money demand model. Also, for predicting future inflation, the estimation results showed that M3 money stock growth is more reliable in Burundi and in Kenya, while M3 money overhang is preferable in Rwanda and M3 money stock in Tanzania. As both country-specific and regional (EAC area) information on monetary quantity growth and its impact on price level is important to know in a monetary union, we considered the EAC area as a single market and attempted to estimate the aggregate (EAC area) demand functions for broad money M2 and M3 using Johansen co-integration analysis. The estimated long-run aggregate money demand models M2 and M3 appeared to be stable over the sample period. However, the aggregate M2 and M3 at the EAC level were proven to be weakly exogenous, which should discard them for consideration at the EAC level as the intermediate targets variables in order to achieve the overall objective of price stability in the EAC region. Instead, short-term interest rate should be given a prominent role in monetary policy framework at the EAC level.
- Full Text:
- Date Issued: 2015
- Authors: Nsabimana, Adelit
- Date: 2015
- Subjects: Monetary policy -- Africa, East , Inflation (Finance) -- Africa, East , Equilibrium (Economics)
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: http://hdl.handle.net/10948/9163 , vital:26470
- Description: This research attempts to evaluate the stability of money demand functions and estimate monetary inflation models in the East African Community (EAC), using quarterly aggregate data that range from 2000Q1 to 2012Q3. We used Johansen co-integration analysis to estimate and analyse the stability of the M3 money demand model for each country member of the EAC. From this estimation, we derived a country-specific measure of money overhang. We compared its forecasting power of future inflation with that of money stock growth, and money stock available in the economy. Regarding country-specific money demand functions, with the exception of Uganda, we identified a reasonable and stable country-specific M3 money demand model. Also, for predicting future inflation, the estimation results showed that M3 money stock growth is more reliable in Burundi and in Kenya, while M3 money overhang is preferable in Rwanda and M3 money stock in Tanzania. As both country-specific and regional (EAC area) information on monetary quantity growth and its impact on price level is important to know in a monetary union, we considered the EAC area as a single market and attempted to estimate the aggregate (EAC area) demand functions for broad money M2 and M3 using Johansen co-integration analysis. The estimated long-run aggregate money demand models M2 and M3 appeared to be stable over the sample period. However, the aggregate M2 and M3 at the EAC level were proven to be weakly exogenous, which should discard them for consideration at the EAC level as the intermediate targets variables in order to achieve the overall objective of price stability in the EAC region. Instead, short-term interest rate should be given a prominent role in monetary policy framework at the EAC level.
- Full Text:
- Date Issued: 2015
Assessing the role of social transfers in curbing household food insecurity in Harare rural district, Zimbabwe
- Nyabvudzi, Tatenda Gaudencia
- Authors: Nyabvudzi, Tatenda Gaudencia
- Date: 2015
- Subjects: Poverty -- Zimbabwe Food security -- Zimbabwe Households -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/12205 , vital:39197
- Description: Purpose – Empirical work on the career development processes of vulnerable groups such as refugees is beginning to receive currency within the academic literature. However, little is known about the intersection of factors such as gender and structural constraints on such processes especially within developing countries such as South Africa. The purpose of this study was to explore the career development processes of women refugees in South Africa. Design/methodology/ approach – A qualitative research approach through narrative inquiry was used. Snowball sampling was employed to select the 20 women refugees who took part in this research. The study location was the city of Port Elizabeth located in the Eastern Cape Province. The three levels of meaning-making incorporated in previous narrative research was utilised to analyse the data. Findings Results show that women refugees are more concerned with a short-term desire to survive and acquire basic commodities than a long-term focus to advance and develop their careers. This is mainly compounded by constraints personal to the individual and those in the environment. Finally, the results illustrate that career development processes of women refugees are affected by the inextricably intertwined factors associated with their gender, immigration status as well as person-environmental factors. Practical implications – The research suggests strategies that policy makers in South Africa and other developing nations that are hosting refugees can use to assist women not just their career development but also their lived experiences. Originality/value – This study extends and advances literature on the career development issues of vulnerable groups such as women refugees especially in developing nations such as South Africa.
- Full Text:
- Date Issued: 2015
- Authors: Nyabvudzi, Tatenda Gaudencia
- Date: 2015
- Subjects: Poverty -- Zimbabwe Food security -- Zimbabwe Households -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/12205 , vital:39197
- Description: Purpose – Empirical work on the career development processes of vulnerable groups such as refugees is beginning to receive currency within the academic literature. However, little is known about the intersection of factors such as gender and structural constraints on such processes especially within developing countries such as South Africa. The purpose of this study was to explore the career development processes of women refugees in South Africa. Design/methodology/ approach – A qualitative research approach through narrative inquiry was used. Snowball sampling was employed to select the 20 women refugees who took part in this research. The study location was the city of Port Elizabeth located in the Eastern Cape Province. The three levels of meaning-making incorporated in previous narrative research was utilised to analyse the data. Findings Results show that women refugees are more concerned with a short-term desire to survive and acquire basic commodities than a long-term focus to advance and develop their careers. This is mainly compounded by constraints personal to the individual and those in the environment. Finally, the results illustrate that career development processes of women refugees are affected by the inextricably intertwined factors associated with their gender, immigration status as well as person-environmental factors. Practical implications – The research suggests strategies that policy makers in South Africa and other developing nations that are hosting refugees can use to assist women not just their career development but also their lived experiences. Originality/value – This study extends and advances literature on the career development issues of vulnerable groups such as women refugees especially in developing nations such as South Africa.
- Full Text:
- Date Issued: 2015
A sociological analysis of biodiversity management in Nigeria
- Authors: Obayi, Bennycharles A
- Date: 2015
- Subjects: Collective behavior , Sustainable biodiversity -- Nigeria , Biodiversity conservation -- Nigeria
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/5277 , vital:20835
- Description: The central thesis of this study addresses biodiversity challenges from a social relations perspective. This is viewed from the standpoint of enhancing sustainable bioresource-use systems from a behaviour change departure. The study reviewed the activities of organisations in Nigeria which focus on bioresource management. The review focused on how the organisations view, conceive and implement activities which aim to address biodiversity loss emphasising how these aspects inform the concept of programme design, planning and implementation. The strategies were weighed against theories and techniques in behaviour change. The study argues that it should be recognised that the challenges of biodiversity loss have a strong relationship with how a society is socially constructed, and that addressing the challenges will require a systematic approach aimed at social construction, using efficient techniques to ensure behaviour change. The objective of the study was to acquire insight on how programmes which aim at addressing biodiversity loss in Nigeria approached behaviour change towards sustainable bioresource-use practise. The study captured these insights in a set of themes which provided an improved analysis on the dynamics of behaviour change and biodiversity management in Nigeria as well as extrapolated these findings to articulate new ideas on how to address the challenges of biodiversity loss in Nigeria. Through analysing basic suppositions and exposing contradictions, social science disciplines examine the credibility of arguments and key concepts that commonly remain unquestioned. Based on this premise, critical assumptions on biodiversity management were challenged by the study. Furthermore, the study articulated questions which have been raised in recent years from a variety of social science perspectives on biodiversity management concerns. The study postulated the need for biodiversity management to be approached from a social-construct perspective in rethinking the discourse on unsustainable bioresource-use patterns. The thesis derives from an eco-sociology framework rooted in human interaction analysis, which is connected with approaches in the social science of functionalism and behaviourism. The concepts and ideas discussed in the thesis lay out the main dimensions relevant to the discourse on behaviour change-biodiversity management. The study’s conceptual and theoretical underpinning discussed biodiversity management concerns from a global context and narrowed the discussion down to country specific contexts. Within these contexts, the study discussed issues of policies, legal systems, political and social systems, practices and programme activities, as part of management concerns. The study compiled relevant views on conservation and protection practises which were in line with internationally accepted norms and practises on biodiversity management. It highlights the challenges of current practises which emphasise strengthening of legal frameworks, policies and practises, and which criminalise actions that contravene ideally-construed conservation precepts as best models of addressing biodiversity loss. It further discussed the emphasis placed on protected-area systems as the main model of biodiversity conservation and argued on the need to rethink the approach within the Nigerian context. The study articulates the role of sociology in ecological discourse and argues that although the knowledge gained by physical and biological sciences are essential in addressing ecological challenges, however, they are not sufficient to understand the driving forces underlying ecological challenges and the phenomenon fundamental to understanding trends and patterns of human factors in biodiversity loss. The study was explored within the methodological framework of phenomenology as the underpinning paradigm using a qualitative approach for analysis. The layouts of the thesis ensure that the research moves from theoretical and conceptual reflections to the actualities of lived realities and situated practices embedded in biodiversity management in Nigeria. The conceptual inclination for the theoretical base for the study analysis was postulated, which articulate the study’s scientific and empirical contributions. The survey method reflects exploratory analytical inquiry which supported the study’s methodological considerations. This was based on the specific data chosen for review, which was informed by the selected organisation’s application of social-construct concepts. Considered from a national perspective, the study assumed that issues of biodiversity management concerns were not to be separated from everyday social realities and the larger social challenges. In view of this consideration, the study analysis looked at historical, political and socio-economic backdrops in Nigeria, which reflected on bioresource-use practises. These are relevant to understand the dynamics and interplay of culture and values in bioresource-use patterns. The study builds on diverse arrays of global frameworks to integrate the major findings of the study. These were compared with related and different dimensions as well as existing theories of human-bioresource interactions. The first aspect of the empirical analysis explored conceptual dimensions which raised questions concerning perceptions of reality and social values that were linked to the strategies of social-constructs expressed through policies, plans and practices. The study’s fundamental empirical dimension explored the forms in which programmes and social institutions were relevant in ensuring behaviour change towards sustainable bioresource-use practise. The analytical sequences observed trends which support facilitation of social change through behaviour change. Another aspect of the empirical analysis focused on revealing the processional dynamics of programme activities to achieve set objectives. This was analysed from the methodical perspective of how the processes were monitored and measured in order to achieve anticipated outcomes. The study summarised the findings and the outcomes by outlining the themes which emerged from the research. The study analysis argued that the ideals of social interventions cannot be different from a society’s inherent and attributed meanings to realities, as well as how they engage with their everyday realities.
- Full Text:
- Date Issued: 2015
- Authors: Obayi, Bennycharles A
- Date: 2015
- Subjects: Collective behavior , Sustainable biodiversity -- Nigeria , Biodiversity conservation -- Nigeria
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/5277 , vital:20835
- Description: The central thesis of this study addresses biodiversity challenges from a social relations perspective. This is viewed from the standpoint of enhancing sustainable bioresource-use systems from a behaviour change departure. The study reviewed the activities of organisations in Nigeria which focus on bioresource management. The review focused on how the organisations view, conceive and implement activities which aim to address biodiversity loss emphasising how these aspects inform the concept of programme design, planning and implementation. The strategies were weighed against theories and techniques in behaviour change. The study argues that it should be recognised that the challenges of biodiversity loss have a strong relationship with how a society is socially constructed, and that addressing the challenges will require a systematic approach aimed at social construction, using efficient techniques to ensure behaviour change. The objective of the study was to acquire insight on how programmes which aim at addressing biodiversity loss in Nigeria approached behaviour change towards sustainable bioresource-use practise. The study captured these insights in a set of themes which provided an improved analysis on the dynamics of behaviour change and biodiversity management in Nigeria as well as extrapolated these findings to articulate new ideas on how to address the challenges of biodiversity loss in Nigeria. Through analysing basic suppositions and exposing contradictions, social science disciplines examine the credibility of arguments and key concepts that commonly remain unquestioned. Based on this premise, critical assumptions on biodiversity management were challenged by the study. Furthermore, the study articulated questions which have been raised in recent years from a variety of social science perspectives on biodiversity management concerns. The study postulated the need for biodiversity management to be approached from a social-construct perspective in rethinking the discourse on unsustainable bioresource-use patterns. The thesis derives from an eco-sociology framework rooted in human interaction analysis, which is connected with approaches in the social science of functionalism and behaviourism. The concepts and ideas discussed in the thesis lay out the main dimensions relevant to the discourse on behaviour change-biodiversity management. The study’s conceptual and theoretical underpinning discussed biodiversity management concerns from a global context and narrowed the discussion down to country specific contexts. Within these contexts, the study discussed issues of policies, legal systems, political and social systems, practices and programme activities, as part of management concerns. The study compiled relevant views on conservation and protection practises which were in line with internationally accepted norms and practises on biodiversity management. It highlights the challenges of current practises which emphasise strengthening of legal frameworks, policies and practises, and which criminalise actions that contravene ideally-construed conservation precepts as best models of addressing biodiversity loss. It further discussed the emphasis placed on protected-area systems as the main model of biodiversity conservation and argued on the need to rethink the approach within the Nigerian context. The study articulates the role of sociology in ecological discourse and argues that although the knowledge gained by physical and biological sciences are essential in addressing ecological challenges, however, they are not sufficient to understand the driving forces underlying ecological challenges and the phenomenon fundamental to understanding trends and patterns of human factors in biodiversity loss. The study was explored within the methodological framework of phenomenology as the underpinning paradigm using a qualitative approach for analysis. The layouts of the thesis ensure that the research moves from theoretical and conceptual reflections to the actualities of lived realities and situated practices embedded in biodiversity management in Nigeria. The conceptual inclination for the theoretical base for the study analysis was postulated, which articulate the study’s scientific and empirical contributions. The survey method reflects exploratory analytical inquiry which supported the study’s methodological considerations. This was based on the specific data chosen for review, which was informed by the selected organisation’s application of social-construct concepts. Considered from a national perspective, the study assumed that issues of biodiversity management concerns were not to be separated from everyday social realities and the larger social challenges. In view of this consideration, the study analysis looked at historical, political and socio-economic backdrops in Nigeria, which reflected on bioresource-use practises. These are relevant to understand the dynamics and interplay of culture and values in bioresource-use patterns. The study builds on diverse arrays of global frameworks to integrate the major findings of the study. These were compared with related and different dimensions as well as existing theories of human-bioresource interactions. The first aspect of the empirical analysis explored conceptual dimensions which raised questions concerning perceptions of reality and social values that were linked to the strategies of social-constructs expressed through policies, plans and practices. The study’s fundamental empirical dimension explored the forms in which programmes and social institutions were relevant in ensuring behaviour change towards sustainable bioresource-use practise. The analytical sequences observed trends which support facilitation of social change through behaviour change. Another aspect of the empirical analysis focused on revealing the processional dynamics of programme activities to achieve set objectives. This was analysed from the methodical perspective of how the processes were monitored and measured in order to achieve anticipated outcomes. The study summarised the findings and the outcomes by outlining the themes which emerged from the research. The study analysis argued that the ideals of social interventions cannot be different from a society’s inherent and attributed meanings to realities, as well as how they engage with their everyday realities.
- Full Text:
- Date Issued: 2015
A comparative study of the in vitro antidiabetic properties, cytotoxicity and mechanism of action of Albuca bracteata and Albuca setosa bulb extracts
- Authors: Odeyemi, Samuel Wale
- Date: 2015
- Subjects: Medicinal plants Herbs -- Therapeutic use Diabetics -- Alternative treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/3154 , vital:28327
- Description: The search for cheap, non toxic and readily available antidiabetic drugs has been a challenge for researchers and the pharmaceutical industries. Diabetes mellitus is a metabolic disease characterized by defects in the synthesis of insulin and/or insensitivity to the action of insulin at the target cells. The disease has been on the increase mostly in developing countries where large proportions of the population have little access to good medical care due to either accessibility or non availability of synthetic drugs. This has led to the use of medicinal plants to treat diabetes because it is safe, cheap and with few side effects. There is little scientific evidence on the dosages, active compounds, mechanisms of action and toxicity of these traditionally used plants. Two of the most frequently used plants; Albuca setosa and Albuca bracteata were investigated in this study. The qualitative analysis of different extractions of these plants revealed the presence of phenolics, alkaloids, tannins and saponins. The antioxidant properties of aqueous, acetone and methanollic extracts of Albuca setosa and Albuca bracteata were investigated using models such as Diphenyl-1-Picrylhydrazyl (DPPH), 2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), Ferric ion reducing antioxidant potential (FRAP), Nitric Oxide and Hydrogen Peroxide (H2O2). Both plants revealed inhibitions against DPPH in a concentration - dependent manner with Albuca setosa (0.330 mg/ml) showing higher activity than Albuca bracteata (0.647 mg/ml) determined from the IC50. The aqueous extract of Albuca setosa showed a higher inhibition against DPPH radical compared to the Albuca bracteata aqueous extract at all concentrations investigated. The isolated saponins from Albuca bracteata had a higher DPPH scavenging activity than the crude methanolic extract of the plant in a concentration - dependent manner but are significantly different from each other at 0.4, 0.6 and 1.0 mg/ml only. The IC50 of the saponins was also observed to be higher than the crude extracts and standards.The Albuca setosa aqueous extract showed a higher percentage inhibition of ABTS radicals than Albuca bracteata at all the concentrations investigated. Overall, the Albuca setosa aqueous extract (0.0809 mg/ml) showed maximum activity against ABTS radicals. The iron reducing power was significantly higher (P < 0.05) in the methanolic extract of both plants compared to the aqueous counterpart. Overall, the Albuca bracteata aqueous extract (0.344 mg/ml) showed maximum activity as indicated by the IC50. The aqueous extracts of both plants also revealed percentage inhibitions in a concentration - dependent manner against NO2. The aqueous extract of Albuca bracteata bulb was more active against nitric oxide and hydrogen peroxide inhibition. In this study, the cytotoxicity of the extracts was evaluated at a high dose of 100 μg/ml on Chang liver cells and determined using MTT, crystal violet, glucose consumption, lactate production and lactate dehydrogenase release and FRAP. The aqueous extracts of both Albuca setosa and Albuca bracteata were non-toxic on Chang liver cells at the concentrations investigated. The MTT revealed that the aqueous extract of Albuca setosa bulb had the optimum cell viability of 108.09 percent while the acetonic extract of Albuca bracteata showed the least cell viability (37.72 percent) compared with the control. The crystal violet test also revealed the acetone extract of Albuca bracteata to have the least percentage of cell viability at 31.47 percent, while the aqueous extract of Albuca setosa showed the maximum cell viability at 112.5 percent. The aqueous extracts of both plants showed higher percentage cell density on the second day of incubation from the proliferation assay. All the tested samples were observed to consume more glucose than the blank except for the methanollic and acetone extracts of Albuca bracteata bulb. The aqueous and methanolic extracts of Albuca setosa bulbs produced the highest lactate with 120.2 μg/ml and 113.7 μg/ml respectively. The acetone extracts of both Albuca setosa and Albuca bracteata revealed toxicity with a higher lactate dehydrogenase release compared to the control.
- Full Text:
- Date Issued: 2015
- Authors: Odeyemi, Samuel Wale
- Date: 2015
- Subjects: Medicinal plants Herbs -- Therapeutic use Diabetics -- Alternative treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/3154 , vital:28327
- Description: The search for cheap, non toxic and readily available antidiabetic drugs has been a challenge for researchers and the pharmaceutical industries. Diabetes mellitus is a metabolic disease characterized by defects in the synthesis of insulin and/or insensitivity to the action of insulin at the target cells. The disease has been on the increase mostly in developing countries where large proportions of the population have little access to good medical care due to either accessibility or non availability of synthetic drugs. This has led to the use of medicinal plants to treat diabetes because it is safe, cheap and with few side effects. There is little scientific evidence on the dosages, active compounds, mechanisms of action and toxicity of these traditionally used plants. Two of the most frequently used plants; Albuca setosa and Albuca bracteata were investigated in this study. The qualitative analysis of different extractions of these plants revealed the presence of phenolics, alkaloids, tannins and saponins. The antioxidant properties of aqueous, acetone and methanollic extracts of Albuca setosa and Albuca bracteata were investigated using models such as Diphenyl-1-Picrylhydrazyl (DPPH), 2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), Ferric ion reducing antioxidant potential (FRAP), Nitric Oxide and Hydrogen Peroxide (H2O2). Both plants revealed inhibitions against DPPH in a concentration - dependent manner with Albuca setosa (0.330 mg/ml) showing higher activity than Albuca bracteata (0.647 mg/ml) determined from the IC50. The aqueous extract of Albuca setosa showed a higher inhibition against DPPH radical compared to the Albuca bracteata aqueous extract at all concentrations investigated. The isolated saponins from Albuca bracteata had a higher DPPH scavenging activity than the crude methanolic extract of the plant in a concentration - dependent manner but are significantly different from each other at 0.4, 0.6 and 1.0 mg/ml only. The IC50 of the saponins was also observed to be higher than the crude extracts and standards.The Albuca setosa aqueous extract showed a higher percentage inhibition of ABTS radicals than Albuca bracteata at all the concentrations investigated. Overall, the Albuca setosa aqueous extract (0.0809 mg/ml) showed maximum activity against ABTS radicals. The iron reducing power was significantly higher (P < 0.05) in the methanolic extract of both plants compared to the aqueous counterpart. Overall, the Albuca bracteata aqueous extract (0.344 mg/ml) showed maximum activity as indicated by the IC50. The aqueous extracts of both plants also revealed percentage inhibitions in a concentration - dependent manner against NO2. The aqueous extract of Albuca bracteata bulb was more active against nitric oxide and hydrogen peroxide inhibition. In this study, the cytotoxicity of the extracts was evaluated at a high dose of 100 μg/ml on Chang liver cells and determined using MTT, crystal violet, glucose consumption, lactate production and lactate dehydrogenase release and FRAP. The aqueous extracts of both Albuca setosa and Albuca bracteata were non-toxic on Chang liver cells at the concentrations investigated. The MTT revealed that the aqueous extract of Albuca setosa bulb had the optimum cell viability of 108.09 percent while the acetonic extract of Albuca bracteata showed the least cell viability (37.72 percent) compared with the control. The crystal violet test also revealed the acetone extract of Albuca bracteata to have the least percentage of cell viability at 31.47 percent, while the aqueous extract of Albuca setosa showed the maximum cell viability at 112.5 percent. The aqueous extracts of both plants showed higher percentage cell density on the second day of incubation from the proliferation assay. All the tested samples were observed to consume more glucose than the blank except for the methanollic and acetone extracts of Albuca bracteata bulb. The aqueous and methanolic extracts of Albuca setosa bulbs produced the highest lactate with 120.2 μg/ml and 113.7 μg/ml respectively. The acetone extracts of both Albuca setosa and Albuca bracteata revealed toxicity with a higher lactate dehydrogenase release compared to the control.
- Full Text:
- Date Issued: 2015