Biochemical mechanisms towards understanding Alzheimer's disease
- Authors: Padayachee, Eden Rebecca
- Date: 2014
- Subjects: Alzheimer's disease Nitric-oxide synthase Biochemical markers Amyloid beta-protein Peptide hormones
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4103 , http://hdl.handle.net/10962/d1011092
- Description: The start of the amyloidogenic pathway in Alzheimer’s disease (AD) begins with the deposition of the Aβ₁₋₄₂ peptide surrounded by astrocytes. High levels of arginine and low amounts of neuronal nitric oxide synthase (nNOS) are associated with AD. These astrocytes store reserve arginine that is eventually metabolized by nNOS, within the vicinity of the Aβ₁₋₄₂ peptide. We propose the existence of an association vs. dissociation equilibrium between Aβ and nNOS such that nNOS is an amyloidogenic catalyst for fibrils. When Aβ binds to nNOS, it inhibits the activity of the enzyme (association phase). However when the amyloid peptide dissociates into a form that can no longer bind, later deduced as a fibril, the activity is restored. Thus, the interaction of Aβ with nNOS could serve to regulate the interaction between nNOS and arginine by restoring activity of the enzyme but at the same time promoting fibrillogenesis. Given this event occurring with the neuron, both nNOS and amyloid can serve as a biomarker for the early onset of AD. The enzyme nNOS catalyzed the formation of fibrils in the presence of Aβ peptides, while Ag nps were shown to reverse the fibril formation from Aβ peptides more so than Au and curcumin either through electrostatic or π-π stacking (aromatic) influences. Our studies have shown that the fragments of Aβ₁₋₄₂ i.e. the pentapeptide (Aβ₁₇₋₂₁) and the three glycine zipper peptides (Aβ₂₅₋₂₉, Aβ₂₉₋₃₃, Aβ₃₃₋₃₇) and the full length glycine zipper stretch (Aβ₂₅₋₃₇) all inhibited nNOS activity to varying degrees. The peptides Aβ₁₇₋₂₁ and Aβ₂₉₋₃₃ with their respective Ki values of 5.1 μM and 7.5 μM inhibited the enzyme the most. The Ki values for reversed sequenced peptides (Aβ₁₇₋₂₁r and Aβ₂₉₋₃₃r) were two fold greater than that of the original peptides while the Ki values for the polar forms (Aβ₁₇₋₂₁p and Aβ₂₉₋₃₃p) were between 3-4 fold greater than that of the original peptides. It was also found that Ag nps (Ki = 0.12 μM) inhibited the activity of nNOS the most compared to Au nps; (Ki = 0.15 μM) and curcumin (Ki = 0.25 μM). At 298K, all the ligands bound at a single site on the enzyme (n=1) and a single Trp residue (θ =1), (later identified as Trp678) was made available on the enzyme surface for quenching by the ligands. Increasing the temperature from 298K-313K, increased the value of Ksv and pointed to a dynamic quenching mechanism for Aβ peptides, nps and curcumin interaction with nNOS. The positive signs for entropy and enthalpy for all Aβ peptides nps and curcumin pointed to hydrophobic–hydrophobic interaction with the enzyme. The fact that Kd increased with temperature emphasized the endothermic nature of the binding reaction and the requirement of thermal energy to aid in diffusion of the ligand to the active site. It was concluded that the binding reaction between the ligands and nNOS was non-spontaneous and endothermic at low temperatures (+ΔG) but spontaneous at high temperatures (-ΔG). The two amino acids Tyr706 and Trp678 moved from their original positions, subject to ligand binding. Trp678 moved a minimum distance of 5 Å toward the heme while Tyr706 moved a maximum distance of 14 Å away from the heme. AutoDock 4.2 was a valuable tool in monitoring the distance of Trp678 within the enzyme interior and fluorescence resonance energy transfer (FRET) was efficient in monitoring the distance moved by Trp residues on the enzyme surface.
- Full Text:
- Date Issued: 2014
- Authors: Padayachee, Eden Rebecca
- Date: 2014
- Subjects: Alzheimer's disease Nitric-oxide synthase Biochemical markers Amyloid beta-protein Peptide hormones
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4103 , http://hdl.handle.net/10962/d1011092
- Description: The start of the amyloidogenic pathway in Alzheimer’s disease (AD) begins with the deposition of the Aβ₁₋₄₂ peptide surrounded by astrocytes. High levels of arginine and low amounts of neuronal nitric oxide synthase (nNOS) are associated with AD. These astrocytes store reserve arginine that is eventually metabolized by nNOS, within the vicinity of the Aβ₁₋₄₂ peptide. We propose the existence of an association vs. dissociation equilibrium between Aβ and nNOS such that nNOS is an amyloidogenic catalyst for fibrils. When Aβ binds to nNOS, it inhibits the activity of the enzyme (association phase). However when the amyloid peptide dissociates into a form that can no longer bind, later deduced as a fibril, the activity is restored. Thus, the interaction of Aβ with nNOS could serve to regulate the interaction between nNOS and arginine by restoring activity of the enzyme but at the same time promoting fibrillogenesis. Given this event occurring with the neuron, both nNOS and amyloid can serve as a biomarker for the early onset of AD. The enzyme nNOS catalyzed the formation of fibrils in the presence of Aβ peptides, while Ag nps were shown to reverse the fibril formation from Aβ peptides more so than Au and curcumin either through electrostatic or π-π stacking (aromatic) influences. Our studies have shown that the fragments of Aβ₁₋₄₂ i.e. the pentapeptide (Aβ₁₇₋₂₁) and the three glycine zipper peptides (Aβ₂₅₋₂₉, Aβ₂₉₋₃₃, Aβ₃₃₋₃₇) and the full length glycine zipper stretch (Aβ₂₅₋₃₇) all inhibited nNOS activity to varying degrees. The peptides Aβ₁₇₋₂₁ and Aβ₂₉₋₃₃ with their respective Ki values of 5.1 μM and 7.5 μM inhibited the enzyme the most. The Ki values for reversed sequenced peptides (Aβ₁₇₋₂₁r and Aβ₂₉₋₃₃r) were two fold greater than that of the original peptides while the Ki values for the polar forms (Aβ₁₇₋₂₁p and Aβ₂₉₋₃₃p) were between 3-4 fold greater than that of the original peptides. It was also found that Ag nps (Ki = 0.12 μM) inhibited the activity of nNOS the most compared to Au nps; (Ki = 0.15 μM) and curcumin (Ki = 0.25 μM). At 298K, all the ligands bound at a single site on the enzyme (n=1) and a single Trp residue (θ =1), (later identified as Trp678) was made available on the enzyme surface for quenching by the ligands. Increasing the temperature from 298K-313K, increased the value of Ksv and pointed to a dynamic quenching mechanism for Aβ peptides, nps and curcumin interaction with nNOS. The positive signs for entropy and enthalpy for all Aβ peptides nps and curcumin pointed to hydrophobic–hydrophobic interaction with the enzyme. The fact that Kd increased with temperature emphasized the endothermic nature of the binding reaction and the requirement of thermal energy to aid in diffusion of the ligand to the active site. It was concluded that the binding reaction between the ligands and nNOS was non-spontaneous and endothermic at low temperatures (+ΔG) but spontaneous at high temperatures (-ΔG). The two amino acids Tyr706 and Trp678 moved from their original positions, subject to ligand binding. Trp678 moved a minimum distance of 5 Å toward the heme while Tyr706 moved a maximum distance of 14 Å away from the heme. AutoDock 4.2 was a valuable tool in monitoring the distance of Trp678 within the enzyme interior and fluorescence resonance energy transfer (FRET) was efficient in monitoring the distance moved by Trp residues on the enzyme surface.
- Full Text:
- Date Issued: 2014
Best practice guideline for the transition of final year nursing students to professional nurses in the military health service in South Africa
- Authors: Caka, Ernestina Masebina
- Date: 2014
- Subjects: School-to-work transition -- South Africa , Nurses -- Training of -- South Africa , Nursing students -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10070 , http://hdl.handle.net/10948/d1021097
- Description: The transition period from student nurses to professional nurses has been acknowledged as being very stressful, particularly in the military health service due to the dual transition. The phase is marked as final year nursing students try to consolidate the experience and knowledge gained during their four year training period with clinical decision making and problem solving skills being applied in the work environment. The students require support and guidance to effect a successful transition from being a student to being a professional nurse. The transition of students in the military health setting might be experienced differently due to the context that is vastly different from the other health care settings (Moore, 2006:541). The aim of the research was to explore the experiences of role transition of final year nursing students, particularly their preparedness to take up the role of a professional nurse in the military health setting in order to assist managers and educators to support and facilitate this professional adjustment appropriately. A qualitative, descriptive, contextual design was employed for the study and followed a three-phase approach. Phase one comprised a qualitative approach, where semi-structured and focus group interviews were conducted to gather the data. Nurse managers, nurse educators, final year nursing students and novice professional nurses formed part of the population for the study. Creswell’s method of data analysis was employed in analysing the data. The second phase dealt with the integrative review of literature on the transition of final year nursing students into professional nurses. Data extracted from the guidelines formed themes that were triangulated to form phase three of the study. Lastly, a best practice guideline was developed to facilitate the transition period of final year nursing students to professional nurses. Principles of trustworthiness were adhered to, participants were treated in a fair manner and confidential information was not divulged without the consent of the participants. Participants were asked to take part voluntarily and without coercion. Ethical approval was requested to give consent for the study to be undertaken and ethical principles were adhered to throughout the study. Findings were then disseminated after the conclusion of the study.
- Full Text:
- Date Issued: 2014
- Authors: Caka, Ernestina Masebina
- Date: 2014
- Subjects: School-to-work transition -- South Africa , Nurses -- Training of -- South Africa , Nursing students -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10070 , http://hdl.handle.net/10948/d1021097
- Description: The transition period from student nurses to professional nurses has been acknowledged as being very stressful, particularly in the military health service due to the dual transition. The phase is marked as final year nursing students try to consolidate the experience and knowledge gained during their four year training period with clinical decision making and problem solving skills being applied in the work environment. The students require support and guidance to effect a successful transition from being a student to being a professional nurse. The transition of students in the military health setting might be experienced differently due to the context that is vastly different from the other health care settings (Moore, 2006:541). The aim of the research was to explore the experiences of role transition of final year nursing students, particularly their preparedness to take up the role of a professional nurse in the military health setting in order to assist managers and educators to support and facilitate this professional adjustment appropriately. A qualitative, descriptive, contextual design was employed for the study and followed a three-phase approach. Phase one comprised a qualitative approach, where semi-structured and focus group interviews were conducted to gather the data. Nurse managers, nurse educators, final year nursing students and novice professional nurses formed part of the population for the study. Creswell’s method of data analysis was employed in analysing the data. The second phase dealt with the integrative review of literature on the transition of final year nursing students into professional nurses. Data extracted from the guidelines formed themes that were triangulated to form phase three of the study. Lastly, a best practice guideline was developed to facilitate the transition period of final year nursing students to professional nurses. Principles of trustworthiness were adhered to, participants were treated in a fair manner and confidential information was not divulged without the consent of the participants. Participants were asked to take part voluntarily and without coercion. Ethical approval was requested to give consent for the study to be undertaken and ethical principles were adhered to throughout the study. Findings were then disseminated after the conclusion of the study.
- Full Text:
- Date Issued: 2014
Behaviour-based health and safety management in construction: a leadership-focused approach
- Authors: Okorie, Victor Nnannaya
- Date: 2014
- Subjects: Construction industry -- Safety measures , Construction industry -- Accidents -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9676 , http://hdl.handle.net/10948/d1021034
- Description: The construction industry remains a pillar in the South African economy, generating employment and wealth. Nonetheless, the industry is reportedly bedevilled by a high rate of accidents and serious injuries that often lead to permanent deformation and fatalities among workers and the general public. These accidents and injuries manifest due to poor construction health and safety (H&S) performance that is often related to poor H&S leadership of the key project leaders involved in the construction business. Shortcomings pertain to client leadership in terms of involvement and commitment to H&S and project H&S related decisions of professionals (designers, project managers, quantity surveyors and engineers). They also pertain to contractor related aspects such as H&S management systems and leadership at all levels of management. In addition, contractors’ inadequacies of H&S management relative to workplace planning and materials related issues have continued to marginalise H&S performance in construction. The H&S leadership of key project leaders is very important in creating a culture of H&S in the workplace. This study examined the H&S management practices and leadership of the key project leaders that contribute to at-risk work practices or unsafe behaviour of workers. Presently, there is limited or no research in South African construction on how the H&S leadership of the key project leaders contributes to at-risk work practices or unsafe behaviour of workers. The methodology employed in the study included an extensive review of relevant literature, which enabled the field work to proceed unhindered. The quantitative survey and qualitative inquiry was conducted with the key construction participants in South African construction. Focus group discussions and interviews were used in a complementary manner. Accordingly, the sampling technique for the study comprised simple random and purposive sampling. The study revealed apparent poor leadership and lack of involvement and commitment to workers’ H&S by the key project leaders. Notably, there is statistical evidence of poor H&S management practices among contractors in terms of top management commitment to and involvement in project H&S. This statistical evidence includes poor H&S education and training of workers and lack of workers’ involvement and participation in H&S matters, which is the tenet of behaviour-based H&S anagement. The model of leadership influence on worker H&S behaviour developed in this research constitutes an innovative contribution to construction H&S performance improvement through a leadership-focused approach. The study has established a basic level of awareness and understanding among key project leaders in that their upstream decisions during the project planning and construction phases have significant influence on workers’ safe or unsafe behaviour or at-risk work practices. The study strongly advocates transparent leadership, ethical behaviour among clients in public and private sectors, designers’ critical H&S decisions, project managers’ and quantity surveyors’ commitment towards project H&S and contractors’ adoption and implementation of behaviour-based H&S management systems. The developed leadership influence model of worker H&S behaviour in the study provides a useful guide for the key project leaders to realise the desired H&S performance improvement in the South African construction industry.
- Full Text:
- Date Issued: 2014
- Authors: Okorie, Victor Nnannaya
- Date: 2014
- Subjects: Construction industry -- Safety measures , Construction industry -- Accidents -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9676 , http://hdl.handle.net/10948/d1021034
- Description: The construction industry remains a pillar in the South African economy, generating employment and wealth. Nonetheless, the industry is reportedly bedevilled by a high rate of accidents and serious injuries that often lead to permanent deformation and fatalities among workers and the general public. These accidents and injuries manifest due to poor construction health and safety (H&S) performance that is often related to poor H&S leadership of the key project leaders involved in the construction business. Shortcomings pertain to client leadership in terms of involvement and commitment to H&S and project H&S related decisions of professionals (designers, project managers, quantity surveyors and engineers). They also pertain to contractor related aspects such as H&S management systems and leadership at all levels of management. In addition, contractors’ inadequacies of H&S management relative to workplace planning and materials related issues have continued to marginalise H&S performance in construction. The H&S leadership of key project leaders is very important in creating a culture of H&S in the workplace. This study examined the H&S management practices and leadership of the key project leaders that contribute to at-risk work practices or unsafe behaviour of workers. Presently, there is limited or no research in South African construction on how the H&S leadership of the key project leaders contributes to at-risk work practices or unsafe behaviour of workers. The methodology employed in the study included an extensive review of relevant literature, which enabled the field work to proceed unhindered. The quantitative survey and qualitative inquiry was conducted with the key construction participants in South African construction. Focus group discussions and interviews were used in a complementary manner. Accordingly, the sampling technique for the study comprised simple random and purposive sampling. The study revealed apparent poor leadership and lack of involvement and commitment to workers’ H&S by the key project leaders. Notably, there is statistical evidence of poor H&S management practices among contractors in terms of top management commitment to and involvement in project H&S. This statistical evidence includes poor H&S education and training of workers and lack of workers’ involvement and participation in H&S matters, which is the tenet of behaviour-based H&S anagement. The model of leadership influence on worker H&S behaviour developed in this research constitutes an innovative contribution to construction H&S performance improvement through a leadership-focused approach. The study has established a basic level of awareness and understanding among key project leaders in that their upstream decisions during the project planning and construction phases have significant influence on workers’ safe or unsafe behaviour or at-risk work practices. The study strongly advocates transparent leadership, ethical behaviour among clients in public and private sectors, designers’ critical H&S decisions, project managers’ and quantity surveyors’ commitment towards project H&S and contractors’ adoption and implementation of behaviour-based H&S management systems. The developed leadership influence model of worker H&S behaviour in the study provides a useful guide for the key project leaders to realise the desired H&S performance improvement in the South African construction industry.
- Full Text:
- Date Issued: 2014
Becoming and being: a critical realist study into the emergence of identity in emergency medical science students, and the construct of graduate attributes
- Authors: Millar, Bernadette Theresa
- Date: 2014
- Subjects: Critical realism , Emergency medical personnel -- Psychology , Emergency medical services
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1327 , http://hdl.handle.net/10962/d1013175
- Description: This critical realist thesis seeks to understand how student, graduate and professional identities emerge in Emergency Medical Science (EMS) students at a South African University of Technology (UoT) as well as in professional paramedics in the Emergency Medical Care Services (EMCS). It further considers the construct of graduate attributes (GAs) and its relationship to emergence of identity and influence on curriculum design. The research design is that of a case study. The theoretical framework is critical realism whose depth ontology posits three domains of reality. Causal powers and generative mechanisms exist in the Real domain which cause events or phenomena to emerge in the Actual domain that are experienced in the Empirical domain. Using retroduction one may come to explore some of the causes for the event. Using Bhaskar’s concepts of identity, the self, absence and emergence, ontology and four-planar social being, a Bhaskarian explanatory framework of identity to explore the emergence of identity has been created. In exploring graduate attributes, a critical realist question is posed: “What must the world be like for GAs to exist” to explore the possibilities of the existence of GAs. It was found that student identity emerges diachronically in three moments, while professional paramedic identity starts to emerge during the third year of study mainly through the structure, culture and agency of workplace-based learning. In answer to the critical realist question it was found that GAs emerge from the neoliberalist commodification of universities. In seeking an alternative to GAs, traits and attitudes were explored. It was found that these emerge from curriculum, interplay of departmental structure, culture and agency of and from students’ being which makes them ontologically radically different from GAs. This study concludes that student, graduate and professional identities emerge from a person’s core constellational identity diachronically within four-planar social being and the interplay of structure, culture and agency. GAs cannot be related to the emergence of identity and curriculum design because of their ontology; however, if traits and attitudes are substituted for GAs, a close relationship does exist between emergence of identity, traits and attitudes and curriculum design.
- Full Text:
- Date Issued: 2014
- Authors: Millar, Bernadette Theresa
- Date: 2014
- Subjects: Critical realism , Emergency medical personnel -- Psychology , Emergency medical services
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1327 , http://hdl.handle.net/10962/d1013175
- Description: This critical realist thesis seeks to understand how student, graduate and professional identities emerge in Emergency Medical Science (EMS) students at a South African University of Technology (UoT) as well as in professional paramedics in the Emergency Medical Care Services (EMCS). It further considers the construct of graduate attributes (GAs) and its relationship to emergence of identity and influence on curriculum design. The research design is that of a case study. The theoretical framework is critical realism whose depth ontology posits three domains of reality. Causal powers and generative mechanisms exist in the Real domain which cause events or phenomena to emerge in the Actual domain that are experienced in the Empirical domain. Using retroduction one may come to explore some of the causes for the event. Using Bhaskar’s concepts of identity, the self, absence and emergence, ontology and four-planar social being, a Bhaskarian explanatory framework of identity to explore the emergence of identity has been created. In exploring graduate attributes, a critical realist question is posed: “What must the world be like for GAs to exist” to explore the possibilities of the existence of GAs. It was found that student identity emerges diachronically in three moments, while professional paramedic identity starts to emerge during the third year of study mainly through the structure, culture and agency of workplace-based learning. In answer to the critical realist question it was found that GAs emerge from the neoliberalist commodification of universities. In seeking an alternative to GAs, traits and attitudes were explored. It was found that these emerge from curriculum, interplay of departmental structure, culture and agency of and from students’ being which makes them ontologically radically different from GAs. This study concludes that student, graduate and professional identities emerge from a person’s core constellational identity diachronically within four-planar social being and the interplay of structure, culture and agency. GAs cannot be related to the emergence of identity and curriculum design because of their ontology; however, if traits and attitudes are substituted for GAs, a close relationship does exist between emergence of identity, traits and attitudes and curriculum design.
- Full Text:
- Date Issued: 2014
Basin analysis of the Soutpansberg and Tuli Coalfields, Limpopo Province of South Africa
- Authors: Malaza, Ntokozo
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Geology)
- Identifier: vital:11531 , http://hdl.handle.net/10353/d1021279
- Description: The Soutpansberg and Tuli Coalfields are both hosted in the Karoo Basin, Limpopo Province of South Africa. The Soutpansberg Coalfield is situated north of the Soutpansberg Mountain Range and has a strike length of about 200 km and width of about 80 km which is fault controlled and extends from Waterpoort in the west to the Kruger National Park in the east. The Tuli Coalfield occurs in a small intracratonic, east-west trending fault-controlled sedimentary basin with a preserved width of 80 km and length of 120 km. The east to west trend of the Tuli Coalfield parallels that of the Soutpansberg Coalfield further east, and the two coalfields link up with the north-south trending Lebombo Basin. The Tuli Coalfield occurs in the Tuli Basin, while the Soutpansberg Coalfield occurs in the Soutpansberg Basin. The two basins preserve a heterogeneous succession of the Upper Paleozoic to Lower Mesozoic sedimentary and volcanic rocks of the Karoo Supergroup. Because the area is largely covered by the Quaternary Kalahari Group sands, the stratigraphy of the succession is not as well understood as the Main Karoo Basin in South Africa. This study deals with the intra-basinal stratigraphic correlation, facies and depositional environments, petrography, geochemistry, provenance, geophysics, structural geology, diagenesis of sandstone, subsidence history and coal quality in the Soutpansberg and Tuli Coalfields. Based on the field work and detailed sedimentological analyses of over 2000 borehole data, seven facies associations (FAs) comprising sixteen major lithofacies were identified. The facies associations are: Glacial diamictite and sandstone (FA 1), Clast supported conglomerate and sandstone (FA 2), Tabular cross-bedded sandstone (FA 3), Trough and planar cross-bedded sandstone (FA 4), Fine calcareous and micaceous siltstone and mudstone (FA 5), Sandy shale/mudstone (FA 6), Laminated or thin-bedded Carbonaceous shale/mudstone and coal (FA 7). The facies associations (FA 1 to FA 7) correspond to the lithostratigraphic sub-divisions of the Tshidzi, Madzaringwe and Mikambeni Formations. The Madzaringwe Formation in this study is informally sub-divided into the Lower, Middle and Upper Members while the Mikambeni Formation is informally sub-divided into the Lower and Upper Members. Sedimentological characteristics of the identified facies associations indicate the following depositional environments: Fluvioglacial (braided streams) depositional environment (FA 1, Tshidzi Diamictite Formation); Floodplain ponds, lakes, marshes and backswamps (FA 6 and FA 7, Lower Member of the Madzaringwe Formation); Meandering and braided channels, crevasse splays, levees and crevasse channels (FA 2, FA 3, FA 4 and FA 5, Middle Member of the Madzaringwe Formation); Floodplain ponds, lakes and backswamps (FA 6 and FA 7, Upper Member of the Madzaringwe Formation); Meandering and braided channels, crevasse splays, swamps and shallow lakes (FA 5, FA 6 and FA 7, Lower Member of the Mikambeni Formation) and lastly braided channels, meandering channels, levees and crevasse channels (FA 2, FA 3, FA 4 and FA 5, Upper Member of the Mikambeni Formation). Paleocurrent directions were measured using directional structures (cross-bedding and asymmetric ripple marks). The paleocurrent analysis shows that the direction of the channels was from south-west to north-east in both coalfields. Based on the structural study and geophysical interpretations, the structural and tectonic settings of the two coalfields have been revealed, both coalfields are normal fault-bounded. The geological evolution of the Karoo strata, at least since the Upper Carboniferous, essentially follows the type model for passive continental margin terrain. Paleostress inversion techniques have been employed to interpret the stress regime of the two coalfields. The Soutpansberg Basin is characterised by W-E to ENE-WSW extension and N-S to NNW-SSE compression. The Tuli Basin is characterised by N-S to NNW-SSE compression and W-E to ENE-WSE extension. This stress field reflects the established structural trend of the two shear belts (the Tshipise and Siloam shear zones) bounding the Central Zone of the Limpopo Mobile Belt. The geophysical interpretations were focused on outlining structures, contacts and on the delineation of gravity, magnetic and radiometric signatures in areas defined as anomalous. The magnetic, gravity and radiometric data showed low amplitudes in the sedimentary strata compared to the surrounding and basement geological bodies. The E-N-E fault system has a notable signature, defining two magnetic domains on both southern and northern sides of the Soutpansberg Coalfield. The intrusive emplacements are mainly fault controlled and they trend in the same direction as the two fault systems. Jurassic volcanics (Letaba and Jozini Formations) follow a SW-NE trend, outcropping in the east (Soutpansberg Basin), producing a strong magnetic response in this area, and partly buried in the west, where magnetic intensity tends to be reduced. Petrographic and geochemical analyses of the Soutpansberg sandstones revealed immature sub-litharenite, sub-arkose and minor arkosic arenites in nature, dominated by sub-angular to rounded detrital grains, sourced from recycled orogens, craton interior to transitional continental. The sandstones of the Tuli Coalfield are classified as sub-arkoses and minor sub-litharenites and sourced from the craton interior and recycled orogen provenances. Both petrographic and geochemical results suggest a passive continental margin source. Petrographic and geochemical results of the samples of the Soutpansberg Coalfield suggest uplifted basement source areas dominated by sedimentary rocks with minor granite-gneiss rocks. The petrography and geochemistry of the Tuli sandstones suggest source areas dominantly composed of plutonic (granites) and metamorphic (gneisses and schists) rocks with a component from a sedimentary (quartz-arenites, quartzites, shales, arkoses and meta-arkoses) rocks. Diagenetic features of Mikambeni and Madzaringwe sandstones are subdivided into early, middle and late stages. Time is relative with the earliest diagenetic event occurring shortly after deposition and the latest occurring up until present time. The main diagenetic processes that have affected the sandstones include mechanical compaction, cementation and the dissolution of framework grains and cements. Early diagenetic processes include mechanical compaction, silica and calcite cementation, clay minerals (pore lining and pore-filling kaolinite, illite and smectite), feldspar authigenesis and the formation of hematite cements and coatings. Late diagenesis includes quartz and feldspar overgrowths, seritisation, chlorite alteration, grain deformation, pressure-solution and fracturing and albitisation. The subsidence of the basins is believed to be initiated and thermally controlled by tectonics (i.e. faults of basements blocks) rather than sedimentary burial. The subsidence within the basins supports the primary graben system which must have been centered within the present basins, and later became a region of major faulting. This gave way to the Late Carboniferous rapid subsidence, with areas of greater extension subsiding more rapidly. The Early Permian (last phase) is characterised by a slow subsidence representing the post-rift thermal subsidence. The rift flanks were gradually uplifted and, and then generally subsided as a results of thermal contraction after the extension terminated. Based on the coal analysis, both coalfields are characterised by coking bituminous coal. The study has revealed that the eastern Soutpansberg Coalfield is likely to present better opportunities for identification of potentially exploitable coal deposits as compared to the Tuli Coalfield.
- Full Text:
- Date Issued: 2014
- Authors: Malaza, Ntokozo
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Geology)
- Identifier: vital:11531 , http://hdl.handle.net/10353/d1021279
- Description: The Soutpansberg and Tuli Coalfields are both hosted in the Karoo Basin, Limpopo Province of South Africa. The Soutpansberg Coalfield is situated north of the Soutpansberg Mountain Range and has a strike length of about 200 km and width of about 80 km which is fault controlled and extends from Waterpoort in the west to the Kruger National Park in the east. The Tuli Coalfield occurs in a small intracratonic, east-west trending fault-controlled sedimentary basin with a preserved width of 80 km and length of 120 km. The east to west trend of the Tuli Coalfield parallels that of the Soutpansberg Coalfield further east, and the two coalfields link up with the north-south trending Lebombo Basin. The Tuli Coalfield occurs in the Tuli Basin, while the Soutpansberg Coalfield occurs in the Soutpansberg Basin. The two basins preserve a heterogeneous succession of the Upper Paleozoic to Lower Mesozoic sedimentary and volcanic rocks of the Karoo Supergroup. Because the area is largely covered by the Quaternary Kalahari Group sands, the stratigraphy of the succession is not as well understood as the Main Karoo Basin in South Africa. This study deals with the intra-basinal stratigraphic correlation, facies and depositional environments, petrography, geochemistry, provenance, geophysics, structural geology, diagenesis of sandstone, subsidence history and coal quality in the Soutpansberg and Tuli Coalfields. Based on the field work and detailed sedimentological analyses of over 2000 borehole data, seven facies associations (FAs) comprising sixteen major lithofacies were identified. The facies associations are: Glacial diamictite and sandstone (FA 1), Clast supported conglomerate and sandstone (FA 2), Tabular cross-bedded sandstone (FA 3), Trough and planar cross-bedded sandstone (FA 4), Fine calcareous and micaceous siltstone and mudstone (FA 5), Sandy shale/mudstone (FA 6), Laminated or thin-bedded Carbonaceous shale/mudstone and coal (FA 7). The facies associations (FA 1 to FA 7) correspond to the lithostratigraphic sub-divisions of the Tshidzi, Madzaringwe and Mikambeni Formations. The Madzaringwe Formation in this study is informally sub-divided into the Lower, Middle and Upper Members while the Mikambeni Formation is informally sub-divided into the Lower and Upper Members. Sedimentological characteristics of the identified facies associations indicate the following depositional environments: Fluvioglacial (braided streams) depositional environment (FA 1, Tshidzi Diamictite Formation); Floodplain ponds, lakes, marshes and backswamps (FA 6 and FA 7, Lower Member of the Madzaringwe Formation); Meandering and braided channels, crevasse splays, levees and crevasse channels (FA 2, FA 3, FA 4 and FA 5, Middle Member of the Madzaringwe Formation); Floodplain ponds, lakes and backswamps (FA 6 and FA 7, Upper Member of the Madzaringwe Formation); Meandering and braided channels, crevasse splays, swamps and shallow lakes (FA 5, FA 6 and FA 7, Lower Member of the Mikambeni Formation) and lastly braided channels, meandering channels, levees and crevasse channels (FA 2, FA 3, FA 4 and FA 5, Upper Member of the Mikambeni Formation). Paleocurrent directions were measured using directional structures (cross-bedding and asymmetric ripple marks). The paleocurrent analysis shows that the direction of the channels was from south-west to north-east in both coalfields. Based on the structural study and geophysical interpretations, the structural and tectonic settings of the two coalfields have been revealed, both coalfields are normal fault-bounded. The geological evolution of the Karoo strata, at least since the Upper Carboniferous, essentially follows the type model for passive continental margin terrain. Paleostress inversion techniques have been employed to interpret the stress regime of the two coalfields. The Soutpansberg Basin is characterised by W-E to ENE-WSW extension and N-S to NNW-SSE compression. The Tuli Basin is characterised by N-S to NNW-SSE compression and W-E to ENE-WSE extension. This stress field reflects the established structural trend of the two shear belts (the Tshipise and Siloam shear zones) bounding the Central Zone of the Limpopo Mobile Belt. The geophysical interpretations were focused on outlining structures, contacts and on the delineation of gravity, magnetic and radiometric signatures in areas defined as anomalous. The magnetic, gravity and radiometric data showed low amplitudes in the sedimentary strata compared to the surrounding and basement geological bodies. The E-N-E fault system has a notable signature, defining two magnetic domains on both southern and northern sides of the Soutpansberg Coalfield. The intrusive emplacements are mainly fault controlled and they trend in the same direction as the two fault systems. Jurassic volcanics (Letaba and Jozini Formations) follow a SW-NE trend, outcropping in the east (Soutpansberg Basin), producing a strong magnetic response in this area, and partly buried in the west, where magnetic intensity tends to be reduced. Petrographic and geochemical analyses of the Soutpansberg sandstones revealed immature sub-litharenite, sub-arkose and minor arkosic arenites in nature, dominated by sub-angular to rounded detrital grains, sourced from recycled orogens, craton interior to transitional continental. The sandstones of the Tuli Coalfield are classified as sub-arkoses and minor sub-litharenites and sourced from the craton interior and recycled orogen provenances. Both petrographic and geochemical results suggest a passive continental margin source. Petrographic and geochemical results of the samples of the Soutpansberg Coalfield suggest uplifted basement source areas dominated by sedimentary rocks with minor granite-gneiss rocks. The petrography and geochemistry of the Tuli sandstones suggest source areas dominantly composed of plutonic (granites) and metamorphic (gneisses and schists) rocks with a component from a sedimentary (quartz-arenites, quartzites, shales, arkoses and meta-arkoses) rocks. Diagenetic features of Mikambeni and Madzaringwe sandstones are subdivided into early, middle and late stages. Time is relative with the earliest diagenetic event occurring shortly after deposition and the latest occurring up until present time. The main diagenetic processes that have affected the sandstones include mechanical compaction, cementation and the dissolution of framework grains and cements. Early diagenetic processes include mechanical compaction, silica and calcite cementation, clay minerals (pore lining and pore-filling kaolinite, illite and smectite), feldspar authigenesis and the formation of hematite cements and coatings. Late diagenesis includes quartz and feldspar overgrowths, seritisation, chlorite alteration, grain deformation, pressure-solution and fracturing and albitisation. The subsidence of the basins is believed to be initiated and thermally controlled by tectonics (i.e. faults of basements blocks) rather than sedimentary burial. The subsidence within the basins supports the primary graben system which must have been centered within the present basins, and later became a region of major faulting. This gave way to the Late Carboniferous rapid subsidence, with areas of greater extension subsiding more rapidly. The Early Permian (last phase) is characterised by a slow subsidence representing the post-rift thermal subsidence. The rift flanks were gradually uplifted and, and then generally subsided as a results of thermal contraction after the extension terminated. Based on the coal analysis, both coalfields are characterised by coking bituminous coal. The study has revealed that the eastern Soutpansberg Coalfield is likely to present better opportunities for identification of potentially exploitable coal deposits as compared to the Tuli Coalfield.
- Full Text:
- Date Issued: 2014
Balanced scorecard components as predictors of service performance management in first bank Nigeria plc 2009 – 2014
- Authors: Agomuonso, Clara Udochi
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (in Public Administration)
- Identifier: vital:11721 , http://hdl.handle.net/10353/d1017866
- Description: Many institutions and organizations are set up to with a right motive but fail to actualize their vision. This cuts across both public and private institutions across the globe. A financial institution is selected for this research because of its sensitivity; hence getting it right with a delicate institution like a financial organization will assist usage of this monitoring system by other institutions. Modern banking in Nigeria started in 1892 with the free banking era which ended when the Banking Ordinance of 1952 was promulgated. First Bank was the pioneer bank that was established in Nigeria in 1894 as the Bank of British West Africa. The establishment of the First Bank of Nigeria predates the birth of the Nigerian nation as a sovereign entity. The bank which was registered as the bank of British West Africa in 1894 has therefore evolved along the path of political, social and economic changes and developments of Nigeria from the colonial period to independence and the experience of post-independence. It thus shared, in the process of its growth, the tidal experiences of the nation which, in retrospect, were sources of strength (Ndekwu, 1994).
- Full Text:
- Date Issued: 2014
- Authors: Agomuonso, Clara Udochi
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (in Public Administration)
- Identifier: vital:11721 , http://hdl.handle.net/10353/d1017866
- Description: Many institutions and organizations are set up to with a right motive but fail to actualize their vision. This cuts across both public and private institutions across the globe. A financial institution is selected for this research because of its sensitivity; hence getting it right with a delicate institution like a financial organization will assist usage of this monitoring system by other institutions. Modern banking in Nigeria started in 1892 with the free banking era which ended when the Banking Ordinance of 1952 was promulgated. First Bank was the pioneer bank that was established in Nigeria in 1894 as the Bank of British West Africa. The establishment of the First Bank of Nigeria predates the birth of the Nigerian nation as a sovereign entity. The bank which was registered as the bank of British West Africa in 1894 has therefore evolved along the path of political, social and economic changes and developments of Nigeria from the colonial period to independence and the experience of post-independence. It thus shared, in the process of its growth, the tidal experiences of the nation which, in retrospect, were sources of strength (Ndekwu, 1994).
- Full Text:
- Date Issued: 2014
Assessment of the monitoring and evaluation tools for transversal training management agency for targeted community based organizations
- Authors: Harbor, Aderonke Omolola
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/1172 , vital:26533
- Description: The purpose of this study was to determine if monitoring and evaluation tools at a local level could help bring about sustainability of rural projects of the community based organizations thereby making the livelihoods of community members better in the Eastern Cape Province. To accomplish this objective, a case study of the training provided by Transversal Training Management Agency (TTMA) was assessed within the concept of the practice of evaluation and seeking to answer four research questions: To what extent should capacity development create sustainable managerial competencies for rural projects? Are monitoring and evaluation tools the key to sustainable projects? How will knowledge and application of M&E tools improve capacity development of CBOs? What are the policy lessons that can be derived from the application of M&E tools for the grass roots groups? The research design was in two parts namely the literature review which focuses on the roles of social change theory and program theory approaches of evaluation which is best applicable for the grassroots, then the case study of TTMA. This was a qualitative research whereby secondary data source was mainly used. The researcher was an employee of TTMA within the period of study, therefore, was able to validate information. Multiple community projects were studied using the secondary data analysis. This was necessary because of the geographic spread of the CBOs that were trained all around the Eastern Cape province and the language barrier would have pose a challenge to the researcher if all project members were to be interviewed. The main findings of the study shows that training was well conducted and project members gave positive feedback about training but what was absent in the training is a study of a monitoring and evaluation framework for the projects‘ members as one of the necessary managerial competencies in order for them to track progress and warning signals in the project cycle before it is too late. In conclusion some recommendations have been made amongst which is a practical handbook of M&E for the grassroots. This provides variety of tools that can best suit the literacy levels of project members that this study targeted. TTMA can therefore, adopt this as part of the training courses for project sustainability.
- Full Text:
- Date Issued: 2014
- Authors: Harbor, Aderonke Omolola
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/1172 , vital:26533
- Description: The purpose of this study was to determine if monitoring and evaluation tools at a local level could help bring about sustainability of rural projects of the community based organizations thereby making the livelihoods of community members better in the Eastern Cape Province. To accomplish this objective, a case study of the training provided by Transversal Training Management Agency (TTMA) was assessed within the concept of the practice of evaluation and seeking to answer four research questions: To what extent should capacity development create sustainable managerial competencies for rural projects? Are monitoring and evaluation tools the key to sustainable projects? How will knowledge and application of M&E tools improve capacity development of CBOs? What are the policy lessons that can be derived from the application of M&E tools for the grass roots groups? The research design was in two parts namely the literature review which focuses on the roles of social change theory and program theory approaches of evaluation which is best applicable for the grassroots, then the case study of TTMA. This was a qualitative research whereby secondary data source was mainly used. The researcher was an employee of TTMA within the period of study, therefore, was able to validate information. Multiple community projects were studied using the secondary data analysis. This was necessary because of the geographic spread of the CBOs that were trained all around the Eastern Cape province and the language barrier would have pose a challenge to the researcher if all project members were to be interviewed. The main findings of the study shows that training was well conducted and project members gave positive feedback about training but what was absent in the training is a study of a monitoring and evaluation framework for the projects‘ members as one of the necessary managerial competencies in order for them to track progress and warning signals in the project cycle before it is too late. In conclusion some recommendations have been made amongst which is a practical handbook of M&E for the grassroots. This provides variety of tools that can best suit the literacy levels of project members that this study targeted. TTMA can therefore, adopt this as part of the training courses for project sustainability.
- Full Text:
- Date Issued: 2014
Assessment of the anti-Listerial properties of Garcinia kola (Heckel) seeds
- Authors: Penduka, Dambudzo
- Date: 2014
- Subjects: Microbial sensitivity tests , Garcinia , Medicinal plants , Traditional medicine
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11278 , http://hdl.handle.net/10353/d1015527 , Microbial sensitivity tests , Garcinia , Medicinal plants , Traditional medicine
- Description: A follow-up of traditional medicinal plants uses is an important tool in highlighting their therapeutic potentials, as they have been found to be a source of a wide range of bioactive compounds that can be used as base compounds for new pharmaceutical drugs. This study therefore focuses on assessing the anti-Listerial properties of the seeds of Garcinia kola (Heckel) plant, which is a traditional medicinal plant of west and central African origin, and was and is still used to traditionally treat several ailments. Four different solvents crude extracts of the seeds were assessed for their anti-Listerial activities in-vitro, against a panel of 42 Listeria bacteria, which included Listeria monocytogenes, Listeria ivanovii and Listeria grayi species. At 10 mg/ml concentration the aqueous extract had activity against 29% of the test isolates while the other three crude extracts namely dichloromethane, n-hexane and the methanol extracts had activity against 45% of the test bacteria. The minimum inhibitory concentration (MIC) ranges of the extracts were 0.079-0.313 mg/ml for the dichloromethane extract; 0.079-0.625 mg/ml for the n-hexane extract; 0.157-0.625 mg/ml for the methanol extract; and 10->10 mg/ml for the aqueous extract. The minimum bactericidal concentration (MBC) ranges of the extracts were 0.625–10 mg/ml for both the n-hexane and the dichloromethane extract; 5-10 mg/ml for the methanol extract; and those for the aqueous extract were above 10 mg/ml against all the susceptible Listeria isolates. The rate of kill analysis was then determined for the three most active crude extracts that is excluding the aqueous extract and it was assessed against four representative Listeria species namely L. monocytogenes (LAL 8), L. grayi (LAL 15), L. ivanovii (LEL 30) and L. ivanovii (LEL 18). All the three extracts showed a general trend of being concentration and time dependent in their rate of kill profiles such that most bacteria cells were killed at the highest test concentration of 4× MIC value after the maximum exposure time of 2 h. The n-hexane, dichloromethane and methanol extracts were bactericidal against 4, 3 and 1 isolates out of the four test Listeria isolates respectively.
- Full Text:
- Date Issued: 2014
- Authors: Penduka, Dambudzo
- Date: 2014
- Subjects: Microbial sensitivity tests , Garcinia , Medicinal plants , Traditional medicine
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11278 , http://hdl.handle.net/10353/d1015527 , Microbial sensitivity tests , Garcinia , Medicinal plants , Traditional medicine
- Description: A follow-up of traditional medicinal plants uses is an important tool in highlighting their therapeutic potentials, as they have been found to be a source of a wide range of bioactive compounds that can be used as base compounds for new pharmaceutical drugs. This study therefore focuses on assessing the anti-Listerial properties of the seeds of Garcinia kola (Heckel) plant, which is a traditional medicinal plant of west and central African origin, and was and is still used to traditionally treat several ailments. Four different solvents crude extracts of the seeds were assessed for their anti-Listerial activities in-vitro, against a panel of 42 Listeria bacteria, which included Listeria monocytogenes, Listeria ivanovii and Listeria grayi species. At 10 mg/ml concentration the aqueous extract had activity against 29% of the test isolates while the other three crude extracts namely dichloromethane, n-hexane and the methanol extracts had activity against 45% of the test bacteria. The minimum inhibitory concentration (MIC) ranges of the extracts were 0.079-0.313 mg/ml for the dichloromethane extract; 0.079-0.625 mg/ml for the n-hexane extract; 0.157-0.625 mg/ml for the methanol extract; and 10->10 mg/ml for the aqueous extract. The minimum bactericidal concentration (MBC) ranges of the extracts were 0.625–10 mg/ml for both the n-hexane and the dichloromethane extract; 5-10 mg/ml for the methanol extract; and those for the aqueous extract were above 10 mg/ml against all the susceptible Listeria isolates. The rate of kill analysis was then determined for the three most active crude extracts that is excluding the aqueous extract and it was assessed against four representative Listeria species namely L. monocytogenes (LAL 8), L. grayi (LAL 15), L. ivanovii (LEL 30) and L. ivanovii (LEL 18). All the three extracts showed a general trend of being concentration and time dependent in their rate of kill profiles such that most bacteria cells were killed at the highest test concentration of 4× MIC value after the maximum exposure time of 2 h. The n-hexane, dichloromethane and methanol extracts were bactericidal against 4, 3 and 1 isolates out of the four test Listeria isolates respectively.
- Full Text:
- Date Issued: 2014
Assessing the optimal size and composition of public debt in Zimbabwe
- Authors: Mupunga, Nebson
- Date: 2014
- Subjects: Debts, Public -- Management , Debts, Public -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: http://hdl.handle.net/10948/8977 , vital:26448
- Description: This study provides an analysis of public debt dynamics with a view to assess the optimal size and composition of public debt in Zimbabwe that is consistent with maintaining public debt at sustainable levels. The analysis was performed by applying public debt data for Zimbabwe over the period 1980 to 2012. Robustness checks were conducted, using data for selected low income countries in the sub-Saharan Africa. The study was motivated by the public debt management concerns caused by the 2008/09 global financial crisis and the European sovereign debt crisis as well as the external public debt overhang experienced by Zimbabwe since the year 2000. The findings of the study complement existing research findings and information on public debt management of the International Monetary Fund (IMF) and other researchers. The major contribution of this thesis is the determination of optimal public debt thresholds for Zimbabwe. The optimal public debt thresholds were estimated from a joint analysis of the macroeconomic variables that affect public debt and the reaction of fiscal policy to changes in debt. The classical linear regression and Bayesian Vector Auto Regression (BVAR) models were applied to examine the drivers of debt accumulation and to assess the sensitivity of debt to macroeconomic shocks. The information from the drivers of public debt accumulation, together with the fiscal response mechanism was used to calibrate the long-run stable (optimal) public debt target. The optimal public debt threshold was also determined by assessing the link between public debt and economic growth. This assessment was carried out to establish the tipping point beyond which public debt adversely affects growth. Such a tipping point provides valuable information on the optimal size of public debt. The study also applied simulation approaches to determine the optimal composition of public debt. The results show that public debt dynamics in Zimbabwe largely comprised extensive stock flow adjustments emanating from extra budgetary expenditures to meet social and political related needs. The results of the assessment on the sensitivity of public debt to macroeconomic shocks show that Zimbabwe‟s public debt has been more vulnerable to economic growth, exchange rate and interest rate shocks. The significant influence of these variables highlights the role of automatic debt dynamics in public debt management. The results from the fiscal reaction function show that government has been responding positively to increases in public debt. This analysis also shows that government‟s policies are a-cyclical; as explained by the negative and insignificant response of the primary balance to the output gap. The dynamic stochastic simulation analysis suggests that Zimbabwe‟s public debt could follow an array of potential paths depending on the policy stance implemented by government. The simulated risk to public debt dynamics is larger, with an upper bound public debt to GDP ratio of 100 per cent and a lower bound public debt ratio of 32 per cent. The simulated lower bound provides a measure of a natural debt limit, which the government could adopt without fearing the risk of default. The results suggest that the main risks to public debt sustainability lie in growth shocks, whose volatility have been high for the period under study. The results from the analysis of growth and debt confirm the existence of an optimal growth maximising public debt ratio depicted by an inverted U-shaped relationship between public debt and economic growth. The optimal size of public debt was found to be at public debt levels of between 45-50 per cent of GDP. This means that higher public debt ratios have been associated with lower economic growth rates at debt levels above 50 per cent of GDP. The results are consistent with empirical findings for low income countries which suggest the existence of a debt laffer-curve. The results from an analysis of an optimal composition of public debt show a trade-off between a debt composition with more external concessional debt and one with more domestic debt. While a composition with more concessional borrowing was found to be desirable from a cost perspective, it proved to be less desirable from a risk perspective after taking into consideration stock flow adjustments due to changes in cross exchange rates. The findings of the study point to a need for the Zimbabwean government to swiftly respond to increases in public debt to control the swings in debt dynamics caused by macroeconomic shocks. The inverted U-shaped relationship between debt and growth suggests that government borrowing must be done in a way that simultaneously entrenches debt sustainability and ensures sustained economic growth rates in the medium to long-term. The study also highlights the need for counter-cyclical macroeconomic policies to avoid explosive debt dynamics emanating from frequent changes in the business cycle, and to minimise the interest/growth rate differential to ensure sustainable public debt dynamics. There is also a need for authorities to ensure a true balance between external and domestic borrowing to minimise the volatility in debt service costs caused by macroeconomic shocks. Generally, the findings from this study can assist in informing the policy agenda to address the imperatives of debt resolution, fiscal consolidation and economic growth acceleration.
- Full Text:
- Date Issued: 2014
- Authors: Mupunga, Nebson
- Date: 2014
- Subjects: Debts, Public -- Management , Debts, Public -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: http://hdl.handle.net/10948/8977 , vital:26448
- Description: This study provides an analysis of public debt dynamics with a view to assess the optimal size and composition of public debt in Zimbabwe that is consistent with maintaining public debt at sustainable levels. The analysis was performed by applying public debt data for Zimbabwe over the period 1980 to 2012. Robustness checks were conducted, using data for selected low income countries in the sub-Saharan Africa. The study was motivated by the public debt management concerns caused by the 2008/09 global financial crisis and the European sovereign debt crisis as well as the external public debt overhang experienced by Zimbabwe since the year 2000. The findings of the study complement existing research findings and information on public debt management of the International Monetary Fund (IMF) and other researchers. The major contribution of this thesis is the determination of optimal public debt thresholds for Zimbabwe. The optimal public debt thresholds were estimated from a joint analysis of the macroeconomic variables that affect public debt and the reaction of fiscal policy to changes in debt. The classical linear regression and Bayesian Vector Auto Regression (BVAR) models were applied to examine the drivers of debt accumulation and to assess the sensitivity of debt to macroeconomic shocks. The information from the drivers of public debt accumulation, together with the fiscal response mechanism was used to calibrate the long-run stable (optimal) public debt target. The optimal public debt threshold was also determined by assessing the link between public debt and economic growth. This assessment was carried out to establish the tipping point beyond which public debt adversely affects growth. Such a tipping point provides valuable information on the optimal size of public debt. The study also applied simulation approaches to determine the optimal composition of public debt. The results show that public debt dynamics in Zimbabwe largely comprised extensive stock flow adjustments emanating from extra budgetary expenditures to meet social and political related needs. The results of the assessment on the sensitivity of public debt to macroeconomic shocks show that Zimbabwe‟s public debt has been more vulnerable to economic growth, exchange rate and interest rate shocks. The significant influence of these variables highlights the role of automatic debt dynamics in public debt management. The results from the fiscal reaction function show that government has been responding positively to increases in public debt. This analysis also shows that government‟s policies are a-cyclical; as explained by the negative and insignificant response of the primary balance to the output gap. The dynamic stochastic simulation analysis suggests that Zimbabwe‟s public debt could follow an array of potential paths depending on the policy stance implemented by government. The simulated risk to public debt dynamics is larger, with an upper bound public debt to GDP ratio of 100 per cent and a lower bound public debt ratio of 32 per cent. The simulated lower bound provides a measure of a natural debt limit, which the government could adopt without fearing the risk of default. The results suggest that the main risks to public debt sustainability lie in growth shocks, whose volatility have been high for the period under study. The results from the analysis of growth and debt confirm the existence of an optimal growth maximising public debt ratio depicted by an inverted U-shaped relationship between public debt and economic growth. The optimal size of public debt was found to be at public debt levels of between 45-50 per cent of GDP. This means that higher public debt ratios have been associated with lower economic growth rates at debt levels above 50 per cent of GDP. The results are consistent with empirical findings for low income countries which suggest the existence of a debt laffer-curve. The results from an analysis of an optimal composition of public debt show a trade-off between a debt composition with more external concessional debt and one with more domestic debt. While a composition with more concessional borrowing was found to be desirable from a cost perspective, it proved to be less desirable from a risk perspective after taking into consideration stock flow adjustments due to changes in cross exchange rates. The findings of the study point to a need for the Zimbabwean government to swiftly respond to increases in public debt to control the swings in debt dynamics caused by macroeconomic shocks. The inverted U-shaped relationship between debt and growth suggests that government borrowing must be done in a way that simultaneously entrenches debt sustainability and ensures sustained economic growth rates in the medium to long-term. The study also highlights the need for counter-cyclical macroeconomic policies to avoid explosive debt dynamics emanating from frequent changes in the business cycle, and to minimise the interest/growth rate differential to ensure sustainable public debt dynamics. There is also a need for authorities to ensure a true balance between external and domestic borrowing to minimise the volatility in debt service costs caused by macroeconomic shocks. Generally, the findings from this study can assist in informing the policy agenda to address the imperatives of debt resolution, fiscal consolidation and economic growth acceleration.
- Full Text:
- Date Issued: 2014
Aspects of the ecology of leopards (Panthera Pardus) in the Little Karoo, South Africa
- Authors: Mann, Gareth
- Date: 2014
- Subjects: Leopard -- South Africa -- Little Karoo Leopard -- Monitoring -- South Africa -- Little Karoo Leopard -- Ecology -- South Africa -- Little Karoo Wildlife monitoring -- South Africa Wildlife conservation -- South Africa Animal populations -- South Africa -- Little Karoo Leopard -- Conservation -- South Africa -- Little Karoo
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5855 , http://hdl.handle.net/10962/d1012241
- Description: Leopards (Panthera pardus) are the most common large predators, free roaming outside of protected areas across most of South Africa. Leopard persistence is attributed to their tolerance of rugged terrain that is subject to less development pressure, as well as their cryptic behaviour. Nevertheless, existing leopard populations are threatened indirectly by ongoing transformation of natural habitat and directly through hunting and conflict with livestock farmers. Together these threats may further isolate leopards to fragmented areas of core natural habitat. I studied leopard habitat preferences, population density, diet and the attitudes of landowners towards leopards in the Little Karoo, Western Cape, South Africa, an area of mixed land-use that contains elements of three overlapping global biodiversity hotspots. Data were gathered between 2010 and 2012 using camera traps set up at 141 sites over an area of ~3100km², GPS tracking collars fitted to three male leopards, scat samples (n=76), interviews with landowners (n=53) analysed in combination with geographical information system (GIS) layers. My results reveal that leopards preferred rugged, mountainous terrain of intermediate elevation, avoiding low-lying, open areas where human disturbance was generally greater. Despite relatively un-fragmented habitat within my study area, the leopard population density (0.75 leopards/100km²) was one of the lowest yet recorded in South Africa. This may reflect low prey densities in mountain refuges in addition to historical human persecution in the area. Currently local landowners are more tolerant of leopards than other wildlife species with incidents of conflict involving leopards being rare relative to black-backed jackals (Canis mesomelas), baboons (Papio hamadryas), caracals (Caracal caracal) and porcupine (Hystrix africaeaustralis). Although current levels of conflict between leopards and stock farmers are low, leopards do depredate livestock, which constitute 10-15% of their diet. Improved livestock husbandry measures and co-operation between conservation authorities and farmers are necessary to mitigate such conflict and balance economic security with biodiversity conservation in the region. Leopards are the only remaining top predators throughout much of the Little Karoo and the Western Cape and as such are predicted to play a critical role in ecosystem structure and the survival of other species. Current high levels of connectivity between areas of suitable leopard habitat bode well for the conservation status of leopards within this region and future conservation efforts need to ensure that narrow corridors linking such habitat are preserved. The potential for leopards to serve as both an umbrella and a flagship species for biodiversity conservation suggests that long term monitoring of this population would be a conservation priority for the Little Karoo.
- Full Text:
- Date Issued: 2014
- Authors: Mann, Gareth
- Date: 2014
- Subjects: Leopard -- South Africa -- Little Karoo Leopard -- Monitoring -- South Africa -- Little Karoo Leopard -- Ecology -- South Africa -- Little Karoo Wildlife monitoring -- South Africa Wildlife conservation -- South Africa Animal populations -- South Africa -- Little Karoo Leopard -- Conservation -- South Africa -- Little Karoo
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5855 , http://hdl.handle.net/10962/d1012241
- Description: Leopards (Panthera pardus) are the most common large predators, free roaming outside of protected areas across most of South Africa. Leopard persistence is attributed to their tolerance of rugged terrain that is subject to less development pressure, as well as their cryptic behaviour. Nevertheless, existing leopard populations are threatened indirectly by ongoing transformation of natural habitat and directly through hunting and conflict with livestock farmers. Together these threats may further isolate leopards to fragmented areas of core natural habitat. I studied leopard habitat preferences, population density, diet and the attitudes of landowners towards leopards in the Little Karoo, Western Cape, South Africa, an area of mixed land-use that contains elements of three overlapping global biodiversity hotspots. Data were gathered between 2010 and 2012 using camera traps set up at 141 sites over an area of ~3100km², GPS tracking collars fitted to three male leopards, scat samples (n=76), interviews with landowners (n=53) analysed in combination with geographical information system (GIS) layers. My results reveal that leopards preferred rugged, mountainous terrain of intermediate elevation, avoiding low-lying, open areas where human disturbance was generally greater. Despite relatively un-fragmented habitat within my study area, the leopard population density (0.75 leopards/100km²) was one of the lowest yet recorded in South Africa. This may reflect low prey densities in mountain refuges in addition to historical human persecution in the area. Currently local landowners are more tolerant of leopards than other wildlife species with incidents of conflict involving leopards being rare relative to black-backed jackals (Canis mesomelas), baboons (Papio hamadryas), caracals (Caracal caracal) and porcupine (Hystrix africaeaustralis). Although current levels of conflict between leopards and stock farmers are low, leopards do depredate livestock, which constitute 10-15% of their diet. Improved livestock husbandry measures and co-operation between conservation authorities and farmers are necessary to mitigate such conflict and balance economic security with biodiversity conservation in the region. Leopards are the only remaining top predators throughout much of the Little Karoo and the Western Cape and as such are predicted to play a critical role in ecosystem structure and the survival of other species. Current high levels of connectivity between areas of suitable leopard habitat bode well for the conservation status of leopards within this region and future conservation efforts need to ensure that narrow corridors linking such habitat are preserved. The potential for leopards to serve as both an umbrella and a flagship species for biodiversity conservation suggests that long term monitoring of this population would be a conservation priority for the Little Karoo.
- Full Text:
- Date Issued: 2014
Architectural design interventions toward improvement of construction health, safety, and ergonomics in South Africa
- Authors: Goldswain, Craig Colin
- Date: 2014
- Subjects: Construction industry -- Safety measures , Construction industry -- Accidents -- South Africa , Architectural design -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9717 , http://hdl.handle.net/10948/d1021060
- Description: The construction industry produces a high rate of accident statistics. Constructors are exposed to a range of construction hazards and risks which manifest themselves in accidents and lead to a high incidence of illnesses, injuries and fatalities. Despite evidence that up to 50 percent of construction accidents can be avoided through mitigation of hazards and risks in the design phase of construction projects, architectural designers do not adequately engage in designing for construction health, safety, and ergonomics. The research localises the problem in the context of South Africa and sets out to develop an architectural design oriented model toward a reduction of construction hazards and risks, which can be engendered through optimisation of tertiary architectural education and through continuing professional development (CPD) programmes. The ultimate aim is to realise a paradigm shift in architectural design relative to construction health, safety, and ergonomics as architectural designers in South Africa still view it as the constructor’s responsibility. The research intertwined a range of secondary data with four provisional studies undertaken in the Eastern Cape Province considered representative of South Africa. This involved both quantitative and qualitative methodologies and were directed at architectural designers registered with the South African Council for the Architectural Profession (SACAP). The provisional studies were published in international conference proceedings and served to gradually provide local insight, and ultimately provided a line of structured questions for use in the main study. The main study was positioned in the action research (AR) paradigm and used focus group (FG) methodology to solicit a vast richness of qualitative data from SACAP registered architectural designers who participated in the FG proceedings. Synthesis of data with literature and the provisional studies gave rise to a provisional model comprising six main model components and a range of sub-components. The provisional model was validated and refined while simultaneously testing the research hypotheses by means of questionnaires directed at the SACAP registered FG participants. The evolved model includes a core model embedded in a greater process model, and implementation and use of the core model relies on appropriate knowledge of architectural designers. It is ultimately recommended that tertiary architectural education institutions and those involved in architectural CPD programmes take ‘upstream design ownership’ and use the model as a basis for designing and implementing appropriate tertiary architectural programmes and architectural CPD offerings. Ultimately the model is not considered as a complete means to an end, and further investigation is needed in order to design and implement the recommended programmes. Only then can we begin to realise a paradigm shift in architectural thinking and practice.
- Full Text:
- Date Issued: 2014
- Authors: Goldswain, Craig Colin
- Date: 2014
- Subjects: Construction industry -- Safety measures , Construction industry -- Accidents -- South Africa , Architectural design -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9717 , http://hdl.handle.net/10948/d1021060
- Description: The construction industry produces a high rate of accident statistics. Constructors are exposed to a range of construction hazards and risks which manifest themselves in accidents and lead to a high incidence of illnesses, injuries and fatalities. Despite evidence that up to 50 percent of construction accidents can be avoided through mitigation of hazards and risks in the design phase of construction projects, architectural designers do not adequately engage in designing for construction health, safety, and ergonomics. The research localises the problem in the context of South Africa and sets out to develop an architectural design oriented model toward a reduction of construction hazards and risks, which can be engendered through optimisation of tertiary architectural education and through continuing professional development (CPD) programmes. The ultimate aim is to realise a paradigm shift in architectural design relative to construction health, safety, and ergonomics as architectural designers in South Africa still view it as the constructor’s responsibility. The research intertwined a range of secondary data with four provisional studies undertaken in the Eastern Cape Province considered representative of South Africa. This involved both quantitative and qualitative methodologies and were directed at architectural designers registered with the South African Council for the Architectural Profession (SACAP). The provisional studies were published in international conference proceedings and served to gradually provide local insight, and ultimately provided a line of structured questions for use in the main study. The main study was positioned in the action research (AR) paradigm and used focus group (FG) methodology to solicit a vast richness of qualitative data from SACAP registered architectural designers who participated in the FG proceedings. Synthesis of data with literature and the provisional studies gave rise to a provisional model comprising six main model components and a range of sub-components. The provisional model was validated and refined while simultaneously testing the research hypotheses by means of questionnaires directed at the SACAP registered FG participants. The evolved model includes a core model embedded in a greater process model, and implementation and use of the core model relies on appropriate knowledge of architectural designers. It is ultimately recommended that tertiary architectural education institutions and those involved in architectural CPD programmes take ‘upstream design ownership’ and use the model as a basis for designing and implementing appropriate tertiary architectural programmes and architectural CPD offerings. Ultimately the model is not considered as a complete means to an end, and further investigation is needed in order to design and implement the recommended programmes. Only then can we begin to realise a paradigm shift in architectural thinking and practice.
- Full Text:
- Date Issued: 2014
Appropriateness of municipal workers' job behaviour and performance at the Buffalo City Metropolitan Municipality
- Authors: Twalo, Thembinkosi Gladden
- Date: 2014
- Subjects: Education -- Employees , Employees -- Attitudes , Employees -- Rating of
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9587 , http://hdl.handle.net/10948/d1020997
- Description: The Buffalo City Metropolitan Municipality (BCMM) has been experiencing inappropriate job behaviour and performance from some of its workers. These inappropriate practices have been widely reported in the media, audit reports, parliamentary discussions, reports to parliament, municipal reports, and departmental reports. They include misappropriation of municipal resources, maladministration, mismanagement, lack of service delivery, fraud, and corruption. Since many BCMM workers have various levels of formal education, such practices are not expected, because the structural-functionalist assumption is that formal education is a solution to societal challenges. At the BCMM, however, formal education seemed to also serve a different purpose, that of realising the principle that says “[k]now the rules well, so you can break them effectively” (Dalai Lama 2013, 2). This study therefore hypothesises that the perpetual inappropriate job behaviour and performance at the BCMM is due to the paucity of broad skills. The concept of broad skills includes the various dimensions of knowledge (know that, know why, know how) as well as attitudes, ethics and values. Inappropriate job behaviour and performance practices thus indicate that current levels of broad skills are insufficient. This study acknowledges that labour (ability to work) is a product of multifarious forms of capital, hence this study amalgamates four forms of capital - human capital, social capital, cultural capital, and reputation capital – into a theoretical framework in order to get a broader explanation of the workers’ job behaviour and performance. The various forms of capital contribute to the formation of skill, hence the notion of broad skills. How workers discharge their responsibilities is determined by numerous factors such as cultural capital (the workers’ family background, race, ethnicity, personality, and geographical area) (Bourdieu 1977); reputation capital (the workers’ brand, public perceptions of trustworthiness, popularity, authority in the field, ethics, integrity and reputation) (Ingbretsen 2011); social capital (the workers’ social development, social relations, and social networks) (Blackmore 1997); and human capital (schooling) (Becker 1964). The value of adopting the broad skills approach lies in gaining a broader perspective on job performance as opposed to the dominant use of the human capital model alone which predominantly uses schooling to explain job performance. In practice, the human capital model is characterised by its association of job performance problems with lack of skills. However, investigation of the role of attitudes, ethics and values in the labour process reveals that the lack of will also contributes to job performance problems. In fact, the adoption of multiple perspectives for investigating the paradoxical co-existence of inappropriate job behaviour and performance with formal education reveals several factors that make this phenomenon possible, besides lack of skills. These include the job environment, ineffective performance management systems, compromised municipal effectiveness and efficiency due to the politicisation of municipal management, and manipulation of the labour process to suit the interests of the workers who want to engage in inappropriate practices.
- Full Text:
- Date Issued: 2014
- Authors: Twalo, Thembinkosi Gladden
- Date: 2014
- Subjects: Education -- Employees , Employees -- Attitudes , Employees -- Rating of
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9587 , http://hdl.handle.net/10948/d1020997
- Description: The Buffalo City Metropolitan Municipality (BCMM) has been experiencing inappropriate job behaviour and performance from some of its workers. These inappropriate practices have been widely reported in the media, audit reports, parliamentary discussions, reports to parliament, municipal reports, and departmental reports. They include misappropriation of municipal resources, maladministration, mismanagement, lack of service delivery, fraud, and corruption. Since many BCMM workers have various levels of formal education, such practices are not expected, because the structural-functionalist assumption is that formal education is a solution to societal challenges. At the BCMM, however, formal education seemed to also serve a different purpose, that of realising the principle that says “[k]now the rules well, so you can break them effectively” (Dalai Lama 2013, 2). This study therefore hypothesises that the perpetual inappropriate job behaviour and performance at the BCMM is due to the paucity of broad skills. The concept of broad skills includes the various dimensions of knowledge (know that, know why, know how) as well as attitudes, ethics and values. Inappropriate job behaviour and performance practices thus indicate that current levels of broad skills are insufficient. This study acknowledges that labour (ability to work) is a product of multifarious forms of capital, hence this study amalgamates four forms of capital - human capital, social capital, cultural capital, and reputation capital – into a theoretical framework in order to get a broader explanation of the workers’ job behaviour and performance. The various forms of capital contribute to the formation of skill, hence the notion of broad skills. How workers discharge their responsibilities is determined by numerous factors such as cultural capital (the workers’ family background, race, ethnicity, personality, and geographical area) (Bourdieu 1977); reputation capital (the workers’ brand, public perceptions of trustworthiness, popularity, authority in the field, ethics, integrity and reputation) (Ingbretsen 2011); social capital (the workers’ social development, social relations, and social networks) (Blackmore 1997); and human capital (schooling) (Becker 1964). The value of adopting the broad skills approach lies in gaining a broader perspective on job performance as opposed to the dominant use of the human capital model alone which predominantly uses schooling to explain job performance. In practice, the human capital model is characterised by its association of job performance problems with lack of skills. However, investigation of the role of attitudes, ethics and values in the labour process reveals that the lack of will also contributes to job performance problems. In fact, the adoption of multiple perspectives for investigating the paradoxical co-existence of inappropriate job behaviour and performance with formal education reveals several factors that make this phenomenon possible, besides lack of skills. These include the job environment, ineffective performance management systems, compromised municipal effectiveness and efficiency due to the politicisation of municipal management, and manipulation of the labour process to suit the interests of the workers who want to engage in inappropriate practices.
- Full Text:
- Date Issued: 2014
An investigation of the question of cyber-ethics in social media-communications within selected South African NGOs
- Authors: Mbinjama-Gamatham, Adelina
- Date: 2014
- Subjects: Social media -- Moral and ethical aspects Non-governmental organizations -- South Africa , Online social networks -- Moral and ethical aspects , Communication -- Social aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/45804 , vital:39196
- Description: The issue of ethics on the internet has become complicated due to a number of people placing material on cyberspace. NGOs are increasingly using social media to promote their products and services. Jürgen Habermas’ theory of communicative action and discourse ethics as a theoretical basis to the study merges together several factors which impact on the use of social media as a communicational tool for social marketing. The study explores how eight “ethical variables” (ethical and moral problems) are impacted by social media. The variables- justice, privacy, access, accuracy, truth, human dignity, regulation and ownership of information are a basis of enquiry by conducting in-depth interviews with employers/managers of 10 selected South African NGOs, as well as distributing survey questionnaires to 150 employees/volunteers of the NGOs to determine their experiences with cyberspace. The research investigates the social contexts of the selected NGOs and the safety measures they implement to protect their reputations and corporate identities. The study analyzes unethical behaviours that exist within the selected virtual organizations of the NGOs and investigates the ethical guidelines they follow in order to deal with the breaches of ethics. The study offers recommendations into amending drafted or existing public procedural policies for the purpose of self-regulating present and future users of social media. The study proposes that the continued misuse of social media may cause social media guidelines to be embedded into existing national legislative frameworks, such as South Africa’s Bill of Rights, as well as media and communications Acts.
- Full Text:
- Date Issued: 2014
- Authors: Mbinjama-Gamatham, Adelina
- Date: 2014
- Subjects: Social media -- Moral and ethical aspects Non-governmental organizations -- South Africa , Online social networks -- Moral and ethical aspects , Communication -- Social aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/45804 , vital:39196
- Description: The issue of ethics on the internet has become complicated due to a number of people placing material on cyberspace. NGOs are increasingly using social media to promote their products and services. Jürgen Habermas’ theory of communicative action and discourse ethics as a theoretical basis to the study merges together several factors which impact on the use of social media as a communicational tool for social marketing. The study explores how eight “ethical variables” (ethical and moral problems) are impacted by social media. The variables- justice, privacy, access, accuracy, truth, human dignity, regulation and ownership of information are a basis of enquiry by conducting in-depth interviews with employers/managers of 10 selected South African NGOs, as well as distributing survey questionnaires to 150 employees/volunteers of the NGOs to determine their experiences with cyberspace. The research investigates the social contexts of the selected NGOs and the safety measures they implement to protect their reputations and corporate identities. The study analyzes unethical behaviours that exist within the selected virtual organizations of the NGOs and investigates the ethical guidelines they follow in order to deal with the breaches of ethics. The study offers recommendations into amending drafted or existing public procedural policies for the purpose of self-regulating present and future users of social media. The study proposes that the continued misuse of social media may cause social media guidelines to be embedded into existing national legislative frameworks, such as South Africa’s Bill of Rights, as well as media and communications Acts.
- Full Text:
- Date Issued: 2014
An investigation of protocol command translation as a means to enable interoperability between networked audio devices
- Authors: Igumbor, Osedum Peter
- Date: 2014
- Subjects: Streaming audio Data transmission systems Computer network protocols Computer networks -- Management Command languages (Computer science)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4689 , http://hdl.handle.net/10962/d1011128
- Description: Digital audio networks allow multiple channels of audio to be streamed between devices. This eliminates the need for many different cables to route audio between devices. An added advantage of digital audio networks is the ability to configure and control the networked devices from a common control point. Common control of networked devices enables a sound engineer to establish and destroy audio stream connections between networked devices that are distances apart. On a digital audio network, an audio transport technology enables the exchange of data streams. Typically, an audio transport technology is capable of transporting both control messages and audio data streams. There exist a number of audio transport technologies. Some of these technologies implement data transport by exchanging OSI/ISO layer 2 data frames, while others transport data within OSI/ISO layer 3 packets. There are some approaches to achieving interoperability between devices that utilize different audio transport technologies. A digital audio device typically implements an audio control protocol, which enables it process configuration and control messages from a remote controller. An audio control protocol also defines the structure of the messages that are exchanged between compliant devices. There are currently a wide range of audio control protocols. Some audio control protocols utilize layer 3 audio transport technology, while others utilize layer 2 audio transport technology. An audio device can only communicate with other devices that implement the same control protocol, irrespective of a common transport technology that connects the devices. The existence of different audio control protocols among devices on a network results in a situation where the devices are unable to communicate with each other. Furthermore, a single control application is unable to establish or destroy audio stream connections between the networked devices, since they implement different control protocols. When an audio engineer is designing an audio network installation, this interoperability challenge restricts the choice of devices that can be included. Even when audio transport interoperability has been achieved, common control of the devices remains a challenge. This research investigates protocol command translation as a means to enable interoperability between networked audio devices that implement different audio control protocols. It proposes the use of a command translator that is capable of receiving messages conforming to one protocol from any of the networked devices, translating the received message to conform to a different control protocol, then transmitting the translated message to the intended target which understands the translated protocol message. In so doing, the command translator enables common control of the networked devices, since a control application is able to configure and control devices that conform to different protocols by utilizing the command translator to perform appropriate protocol translation.
- Full Text:
- Date Issued: 2014
- Authors: Igumbor, Osedum Peter
- Date: 2014
- Subjects: Streaming audio Data transmission systems Computer network protocols Computer networks -- Management Command languages (Computer science)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4689 , http://hdl.handle.net/10962/d1011128
- Description: Digital audio networks allow multiple channels of audio to be streamed between devices. This eliminates the need for many different cables to route audio between devices. An added advantage of digital audio networks is the ability to configure and control the networked devices from a common control point. Common control of networked devices enables a sound engineer to establish and destroy audio stream connections between networked devices that are distances apart. On a digital audio network, an audio transport technology enables the exchange of data streams. Typically, an audio transport technology is capable of transporting both control messages and audio data streams. There exist a number of audio transport technologies. Some of these technologies implement data transport by exchanging OSI/ISO layer 2 data frames, while others transport data within OSI/ISO layer 3 packets. There are some approaches to achieving interoperability between devices that utilize different audio transport technologies. A digital audio device typically implements an audio control protocol, which enables it process configuration and control messages from a remote controller. An audio control protocol also defines the structure of the messages that are exchanged between compliant devices. There are currently a wide range of audio control protocols. Some audio control protocols utilize layer 3 audio transport technology, while others utilize layer 2 audio transport technology. An audio device can only communicate with other devices that implement the same control protocol, irrespective of a common transport technology that connects the devices. The existence of different audio control protocols among devices on a network results in a situation where the devices are unable to communicate with each other. Furthermore, a single control application is unable to establish or destroy audio stream connections between the networked devices, since they implement different control protocols. When an audio engineer is designing an audio network installation, this interoperability challenge restricts the choice of devices that can be included. Even when audio transport interoperability has been achieved, common control of the devices remains a challenge. This research investigates protocol command translation as a means to enable interoperability between networked audio devices that implement different audio control protocols. It proposes the use of a command translator that is capable of receiving messages conforming to one protocol from any of the networked devices, translating the received message to conform to a different control protocol, then transmitting the translated message to the intended target which understands the translated protocol message. In so doing, the command translator enables common control of the networked devices, since a control application is able to configure and control devices that conform to different protocols by utilizing the command translator to perform appropriate protocol translation.
- Full Text:
- Date Issued: 2014
An investigation of parameter relationships in a high-speed digital multimedia environment
- Authors: Chigwamba, Nyasha
- Date: 2014
- Subjects: Multimedia communications , Digital communications , Local area networks (Computer networks) , Computer network architectures , Computer network protocols , Computer sound processing , Sound -- Recording and reproducing -- Digital techniques
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4725 , http://hdl.handle.net/10962/d1021153
- Description: With the rapid adoption of multimedia network technologies, a number of companies and standards bodies are introducing technologies that enhance user experience in networked multimedia environments. These technologies focus on device discovery, connection management, control, and monitoring. This study focused on control and monitoring. Multimedia networks make it possible for devices that are part of the same network to reside in different physical locations. These devices contain parameters that are used to control particular features, such as speaker volume, bass, amplifier gain, and video resolution. It is often necessary for changes in one parameter to affect other parameters, such as a synchronised change between volume and bass parameters, or collective control of multiple parameters. Thus, relationships are required between the parameters. In addition, some devices contain parameters, such as voltage, temperature, and audio level, that require constant monitoring to enable corrective action when thresholds are exceeded. Therefore, a mechanism for monitoring networked devices is required. This thesis proposes relationships that are essential for the proper functioning of a multimedia network and that should, therefore, be incorporated in standard form into a protocol, such that all devices can depend on them. Implementation mechanisms for these relationships were created. Parameter grouping and monitoring capabilities within mixing console implementations and existing control protocols were reviewed. A number of requirements for parameter grouping and monitoring were derived from this review. These requirements include a formal classification of relationship types, the ability to create relationships between parameters with different underlying value units, the ability to create relationships between parameters residing on different devices on a network, and the use of an event-driven mechanism for parameter monitoring. These requirements were the criteria used to govern the implementation mechanisms that were created as part of this study. Parameter grouping and monitoring mechanisms were implemented for the XFN protocol. The mechanisms implemented fulfil the requirements derived from the review of capabilities of mixing consoles and existing control protocols. The formal classification of relationship types was implemented within XFN parameters using lists that keep track of the relationships between each XFN parameter and other XFN parameters that reside on the same device or on other devices on the network. A common value unit, known as the global unit, was defined for use as the value format within value update messages between XFN parameters that have relationships. Mapping tables were used to translate the global unit values to application-specific (universal) units, such as decibels (dB). A mechanism for bulk parameter retrieval within the XFN protocol was augmented to produce an event-driven mechanism for parameter monitoring. These implementation mechanisms were applied to an XFN-protocol-compliant graphical control application to demonstrate their usage within an end user context. At the time of this study, the XFN protocol was undergoing standardisation within the Audio Engineering Society. The AES-64 standard has now been approved. Most of the implementation mechanisms resulting from this study have been incorporated into this standard.
- Full Text:
- Date Issued: 2014
- Authors: Chigwamba, Nyasha
- Date: 2014
- Subjects: Multimedia communications , Digital communications , Local area networks (Computer networks) , Computer network architectures , Computer network protocols , Computer sound processing , Sound -- Recording and reproducing -- Digital techniques
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4725 , http://hdl.handle.net/10962/d1021153
- Description: With the rapid adoption of multimedia network technologies, a number of companies and standards bodies are introducing technologies that enhance user experience in networked multimedia environments. These technologies focus on device discovery, connection management, control, and monitoring. This study focused on control and monitoring. Multimedia networks make it possible for devices that are part of the same network to reside in different physical locations. These devices contain parameters that are used to control particular features, such as speaker volume, bass, amplifier gain, and video resolution. It is often necessary for changes in one parameter to affect other parameters, such as a synchronised change between volume and bass parameters, or collective control of multiple parameters. Thus, relationships are required between the parameters. In addition, some devices contain parameters, such as voltage, temperature, and audio level, that require constant monitoring to enable corrective action when thresholds are exceeded. Therefore, a mechanism for monitoring networked devices is required. This thesis proposes relationships that are essential for the proper functioning of a multimedia network and that should, therefore, be incorporated in standard form into a protocol, such that all devices can depend on them. Implementation mechanisms for these relationships were created. Parameter grouping and monitoring capabilities within mixing console implementations and existing control protocols were reviewed. A number of requirements for parameter grouping and monitoring were derived from this review. These requirements include a formal classification of relationship types, the ability to create relationships between parameters with different underlying value units, the ability to create relationships between parameters residing on different devices on a network, and the use of an event-driven mechanism for parameter monitoring. These requirements were the criteria used to govern the implementation mechanisms that were created as part of this study. Parameter grouping and monitoring mechanisms were implemented for the XFN protocol. The mechanisms implemented fulfil the requirements derived from the review of capabilities of mixing consoles and existing control protocols. The formal classification of relationship types was implemented within XFN parameters using lists that keep track of the relationships between each XFN parameter and other XFN parameters that reside on the same device or on other devices on the network. A common value unit, known as the global unit, was defined for use as the value format within value update messages between XFN parameters that have relationships. Mapping tables were used to translate the global unit values to application-specific (universal) units, such as decibels (dB). A mechanism for bulk parameter retrieval within the XFN protocol was augmented to produce an event-driven mechanism for parameter monitoring. These implementation mechanisms were applied to an XFN-protocol-compliant graphical control application to demonstrate their usage within an end user context. At the time of this study, the XFN protocol was undergoing standardisation within the Audio Engineering Society. The AES-64 standard has now been approved. Most of the implementation mechanisms resulting from this study have been incorporated into this standard.
- Full Text:
- Date Issued: 2014
An investigation into XSets of primitive behaviours for emergent behaviour in stigmergic and message passing antlike agents
- Authors: Chibaya, Colin
- Date: 2014
- Subjects: Ants -- Behavior -- Computer programs , Insects -- Behavior -- Computer programs , Ant communities -- Behavior , Insect societies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4698 , http://hdl.handle.net/10962/d1012965
- Description: Ants are fascinating creatures - not so much because they are intelligent on their own, but because as a group they display compelling emergent behaviour (the extent to which one observes features in a swarm which cannot be traced back to the actions of swarm members). What does each swarm member do which allows deliberate engineering of emergent behaviour? We investigate the development of a language for programming swarms of ant agents towards desired emergent behaviour. Five aspects of stigmergic (pheromone sensitive computational devices in which a non-symbolic form of communication that is indirectly mediated via the environment arises) and message passing ant agents (computational devices which rely on implicit communication spaces in which direction vectors are shared one-on-one) are studied. First, we investigate the primitive behaviours which characterize ant agents' discrete actions at individual levels. Ten such primitive behaviours are identified as candidate building blocks of the ant agent language sought. We then study mechanisms in which primitive behaviours are put together into XSets (collection of primitive behaviours, parameter values, and meta information which spells out how and when primitive behaviours are used). Various permutations of XSets are possible which define the search space for best performer XSets for particular tasks. Genetic programming principles are proposed as a search strategy for best performer XSets that would allow particular emergent behaviour to occur. XSets in the search space are evolved over various genetic generations and tested for abilities to allow path finding (as proof of concept). XSets are ranked according to the indices of merit (fitness measures which indicate how well XSets allow particular emergent behaviour to occur) they achieve. Best performer XSets for the path finding task are identifed and reported. We validate the results yield when best performer XSets are used with regard to normality, correlation, similarities in variation, and similarities between mean performances over time. Commonly, the simulation results yield pass most statistical tests. The last aspect we study is the application of best performer XSets to different problem tasks. Five experiments are administered in this regard. The first experiment assesses XSets' abilities to allow multiple targets location (ant agents' abilities to locate continuous regions of targets), and found out that best performer XSets are problem independent. However both categories of XSets are sensitive to changes in agent density. We test the influences of individual primitive behaviours and the effects of the sequences of primitive behaviours to the indices of merit of XSets and found out that most primitive behaviours are indispensable, especially when specific sequences are prescribed. The effects of pheromone dissipation to the indices of merit of stigmergic XSets are also scrutinized. Precisely, dissipation is not causal. Rather, it enhances convergence. Overall, this work successfully identify the discrete primitive behaviours of stigmergic and message passing ant-like devices. It successfully put these primitive behaviours together into XSets which characterize a language for programming ant-like devices towards desired emergent behaviour. This XSets approach is a new ant language representation with which a wider domain of emergent tasks can be resolved.
- Full Text:
- Date Issued: 2014
- Authors: Chibaya, Colin
- Date: 2014
- Subjects: Ants -- Behavior -- Computer programs , Insects -- Behavior -- Computer programs , Ant communities -- Behavior , Insect societies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4698 , http://hdl.handle.net/10962/d1012965
- Description: Ants are fascinating creatures - not so much because they are intelligent on their own, but because as a group they display compelling emergent behaviour (the extent to which one observes features in a swarm which cannot be traced back to the actions of swarm members). What does each swarm member do which allows deliberate engineering of emergent behaviour? We investigate the development of a language for programming swarms of ant agents towards desired emergent behaviour. Five aspects of stigmergic (pheromone sensitive computational devices in which a non-symbolic form of communication that is indirectly mediated via the environment arises) and message passing ant agents (computational devices which rely on implicit communication spaces in which direction vectors are shared one-on-one) are studied. First, we investigate the primitive behaviours which characterize ant agents' discrete actions at individual levels. Ten such primitive behaviours are identified as candidate building blocks of the ant agent language sought. We then study mechanisms in which primitive behaviours are put together into XSets (collection of primitive behaviours, parameter values, and meta information which spells out how and when primitive behaviours are used). Various permutations of XSets are possible which define the search space for best performer XSets for particular tasks. Genetic programming principles are proposed as a search strategy for best performer XSets that would allow particular emergent behaviour to occur. XSets in the search space are evolved over various genetic generations and tested for abilities to allow path finding (as proof of concept). XSets are ranked according to the indices of merit (fitness measures which indicate how well XSets allow particular emergent behaviour to occur) they achieve. Best performer XSets for the path finding task are identifed and reported. We validate the results yield when best performer XSets are used with regard to normality, correlation, similarities in variation, and similarities between mean performances over time. Commonly, the simulation results yield pass most statistical tests. The last aspect we study is the application of best performer XSets to different problem tasks. Five experiments are administered in this regard. The first experiment assesses XSets' abilities to allow multiple targets location (ant agents' abilities to locate continuous regions of targets), and found out that best performer XSets are problem independent. However both categories of XSets are sensitive to changes in agent density. We test the influences of individual primitive behaviours and the effects of the sequences of primitive behaviours to the indices of merit of XSets and found out that most primitive behaviours are indispensable, especially when specific sequences are prescribed. The effects of pheromone dissipation to the indices of merit of stigmergic XSets are also scrutinized. Precisely, dissipation is not causal. Rather, it enhances convergence. Overall, this work successfully identify the discrete primitive behaviours of stigmergic and message passing ant-like devices. It successfully put these primitive behaviours together into XSets which characterize a language for programming ant-like devices towards desired emergent behaviour. This XSets approach is a new ant language representation with which a wider domain of emergent tasks can be resolved.
- Full Text:
- Date Issued: 2014
An investigation into the development of knowledge and strategies for the teaching of visual literacy in under-resourced Eastern Cape schools
- Authors: Mbelani, Madeyandile
- Date: 2014
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64401 , vital:28540
- Description: This thesis reports on a multiple case study PhD project that aimed to investigate meaningful and critical development of knowledge and strategies to teach visual literacy, a component of English First Additional Language (FAL) in six under-resourced schools of the Eastern Cape of South Africa. The study begins by locating visual literacy within a broad framework of literacy as a social practice, and discusses its importance. Further, it discusses complexities of making sense of and teaching visual literacy, especially for the majority of in-service teachers who experienced visual literacy neither as learners nor as teacher trainees. The gap between the curriculum and teachers’ classroom practices is what triggered this study to adopt a transformative paradigm. The main research question is, “How can teacher professional development in English Language Teaching advance in-service teachers’ knowledge of and strategies for meaningful and critical teaching and learning of visual literacy?” To respond to this question, I drew on cultural historical activity theory (CHAT) and critical realism (CR) to design four phases of this study that incorporated the seven stages of an expansive learning cycle. These phases focussed on exploring and expanding teachers’ sense making and teaching of visual literacy. I collected data through interviews, document analysis, videoed lessons and change laboratory (CL) workshops. I designed a data analysis tool that brought together CHAT, CR, multimodal social semiotics, critical discourse analysis and pedagogical discourse to make sense of the data. Through a process of reflexivity, the study illuminated layers of factors that constrained meaningful and critical teaching of visual literacy in the empirical, the actual and the real domains of reality. These factors include teachers’ unconscious reproduction of discourses of domination, their intolerance of diverse cultural discourses, resistance to curriculum change, and the fact that they are comfortable with the status quo. I brought these factors to CL workshops for expansive learning. The study contributes in-depth insight into English FAL in-service teacher development in the area of visual literacy. By locating the study within meaning making and teaching of visual literacy, it was possible to interrogate access, diversity, domination and design in teachers’ classroom practices. As a result of this study participants were made aware of the extent to which these factors enabled or hindered meaningful and critical teaching. Participants repositioned themselves as subjects of the activity system, thereby mobilising their agency to take control of the structures and cultures that condition their teaching.
- Full Text:
- Date Issued: 2014
- Authors: Mbelani, Madeyandile
- Date: 2014
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64401 , vital:28540
- Description: This thesis reports on a multiple case study PhD project that aimed to investigate meaningful and critical development of knowledge and strategies to teach visual literacy, a component of English First Additional Language (FAL) in six under-resourced schools of the Eastern Cape of South Africa. The study begins by locating visual literacy within a broad framework of literacy as a social practice, and discusses its importance. Further, it discusses complexities of making sense of and teaching visual literacy, especially for the majority of in-service teachers who experienced visual literacy neither as learners nor as teacher trainees. The gap between the curriculum and teachers’ classroom practices is what triggered this study to adopt a transformative paradigm. The main research question is, “How can teacher professional development in English Language Teaching advance in-service teachers’ knowledge of and strategies for meaningful and critical teaching and learning of visual literacy?” To respond to this question, I drew on cultural historical activity theory (CHAT) and critical realism (CR) to design four phases of this study that incorporated the seven stages of an expansive learning cycle. These phases focussed on exploring and expanding teachers’ sense making and teaching of visual literacy. I collected data through interviews, document analysis, videoed lessons and change laboratory (CL) workshops. I designed a data analysis tool that brought together CHAT, CR, multimodal social semiotics, critical discourse analysis and pedagogical discourse to make sense of the data. Through a process of reflexivity, the study illuminated layers of factors that constrained meaningful and critical teaching of visual literacy in the empirical, the actual and the real domains of reality. These factors include teachers’ unconscious reproduction of discourses of domination, their intolerance of diverse cultural discourses, resistance to curriculum change, and the fact that they are comfortable with the status quo. I brought these factors to CL workshops for expansive learning. The study contributes in-depth insight into English FAL in-service teacher development in the area of visual literacy. By locating the study within meaning making and teaching of visual literacy, it was possible to interrogate access, diversity, domination and design in teachers’ classroom practices. As a result of this study participants were made aware of the extent to which these factors enabled or hindered meaningful and critical teaching. Participants repositioned themselves as subjects of the activity system, thereby mobilising their agency to take control of the structures and cultures that condition their teaching.
- Full Text:
- Date Issued: 2014
An investigation into the bacterial diversity associated with South African latrunculid sponges that produce bioactive secondary metabolites
- Authors: Walmsley, Tara Aisling
- Date: 2014
- Subjects: Sponges -- South Africa -- Algoa Bay , Sponges -- Classification , Metabolites -- South Africa -- Algoa Bay , Marine metabolites -- South Africa -- Algoa Bay , PQQ (Biochemistry) , Bacterial diversity
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4109 , http://hdl.handle.net/10962/d1012943
- Description: Algoa Bay Latrunculid sponges are well known for their production of cytotoxic pyrroloiminoquinones with speculation that these secondary metabolites may have a microbial origin. This study describes a thorough investigation into the bacterial community associated with Tsitsikamma favus, Tsitsikamma scurra a newly described Latrunculia sp. and a yellow encrusting sponge associated with T. scurra. Molecular and chemical characterisation were used in conjunction with traditional taxonomy in identification of the sponge specimens. The 28S rRNA and COX1 analysis confirmed the traditional taxonomy with T. favus and T. scurra being very closely related. Chemical analysis revealed that T. favus and T. scurra shared the discorhabdins 2,4-debromo-3-dihydrodiscorhabdin C, 7,8-dehydro-3-dihydrodiscorhabdin C and 14-bromo-1-hydroxy-discorhabdin V in common with each other and Tsitsikamma pedunculata indicating that these pyrroloiminoquinones are common to Tsitsikamma sponges in general. The bacterial community associated with T. favus was explored using 16S rRNA molecular techniques including DGGE, clonal libraries of full length 16S rRNA genes, as well as 454 pyrosequencing. DGGE analysis revealed that the bacterial community associated with T. favus appeared to be highly conserved, which was confirmed by both the clone library and 454 pyrosequencing, with the Betaproteobacteria as the most dominant class. Further exploration into T. favus, as well as T. scurra, Latrunculia sp. and the yellow encrusting sponge indicated that the bacterial populations associated with each of these sponge species were conserved and species specific. OTU analysis to the species level revealed that T. favus and T. scurra shared an abundant Spirochaete species in common while the most abundant species in the Latrunculia sp. and the yellow encrusting sponge belonged to the class Betaproteobacteria. The exclusivity of the tsitsikammamines to T. favus precipitated attempts to culture the T. favus associated bacteria, with a focus on the dominant betaproteobacterium as indicated by the 16S rRNA clone library. Actinobacteria associated with the Algoa Bay sponge specimens were also cultured and the actinobacterial isolates were sent for screening against Mycobacterium aurum with two Kocuria kristinae isolates and a Streptomyces albdioflavus isolate showing good antimycobacterial activity.
- Full Text:
- Date Issued: 2014
- Authors: Walmsley, Tara Aisling
- Date: 2014
- Subjects: Sponges -- South Africa -- Algoa Bay , Sponges -- Classification , Metabolites -- South Africa -- Algoa Bay , Marine metabolites -- South Africa -- Algoa Bay , PQQ (Biochemistry) , Bacterial diversity
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4109 , http://hdl.handle.net/10962/d1012943
- Description: Algoa Bay Latrunculid sponges are well known for their production of cytotoxic pyrroloiminoquinones with speculation that these secondary metabolites may have a microbial origin. This study describes a thorough investigation into the bacterial community associated with Tsitsikamma favus, Tsitsikamma scurra a newly described Latrunculia sp. and a yellow encrusting sponge associated with T. scurra. Molecular and chemical characterisation were used in conjunction with traditional taxonomy in identification of the sponge specimens. The 28S rRNA and COX1 analysis confirmed the traditional taxonomy with T. favus and T. scurra being very closely related. Chemical analysis revealed that T. favus and T. scurra shared the discorhabdins 2,4-debromo-3-dihydrodiscorhabdin C, 7,8-dehydro-3-dihydrodiscorhabdin C and 14-bromo-1-hydroxy-discorhabdin V in common with each other and Tsitsikamma pedunculata indicating that these pyrroloiminoquinones are common to Tsitsikamma sponges in general. The bacterial community associated with T. favus was explored using 16S rRNA molecular techniques including DGGE, clonal libraries of full length 16S rRNA genes, as well as 454 pyrosequencing. DGGE analysis revealed that the bacterial community associated with T. favus appeared to be highly conserved, which was confirmed by both the clone library and 454 pyrosequencing, with the Betaproteobacteria as the most dominant class. Further exploration into T. favus, as well as T. scurra, Latrunculia sp. and the yellow encrusting sponge indicated that the bacterial populations associated with each of these sponge species were conserved and species specific. OTU analysis to the species level revealed that T. favus and T. scurra shared an abundant Spirochaete species in common while the most abundant species in the Latrunculia sp. and the yellow encrusting sponge belonged to the class Betaproteobacteria. The exclusivity of the tsitsikammamines to T. favus precipitated attempts to culture the T. favus associated bacteria, with a focus on the dominant betaproteobacterium as indicated by the 16S rRNA clone library. Actinobacteria associated with the Algoa Bay sponge specimens were also cultured and the actinobacterial isolates were sent for screening against Mycobacterium aurum with two Kocuria kristinae isolates and a Streptomyces albdioflavus isolate showing good antimycobacterial activity.
- Full Text:
- Date Issued: 2014
An integrated approach for the delineation of arable land and its cropping suitability under variable soil and climatic conditions in the Nkonkobe municipality, Eastern Cape, South Africa
- Authors: Manyevere, Alen
- Date: 2014
- Subjects: Soils -- Classification -- South Africa -- Eastern Cape , Soil degradation -- South Africa -- Eastern Cape , Ethnoscience -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11965 , http://hdl.handle.net/10353/d1019856 , Soils -- Classification -- South Africa -- Eastern Cape , Soil degradation -- South Africa -- Eastern Cape , Ethnoscience -- South Africa -- Eastern Cape
- Description: Arable crop production in Nkonkobe Municipality is low due to abandonment of potentially productive land and low productivity of the cultivated land. Little attention has been given to farmers perspectives with regards to crop production and land abandonment. Understanding the relationships of indigenous knowledge systems, where local approaches to soil classification, appraisal, use and management and land evaluation, and scientific approaches could be important for the effective use of available soil resources while avoiding those resources that are vulnerable to degradation. In addition, the interactions between soil factors and climate could be useful in understanding the erodibility of soils. The intergration of scientific research and indigenous knowledge systems could help in the identification and delineation of high potential land and on crop suitability evaluation. The objectives of the study were: (i) to determine farmers‟ perspectives with regards to land utilisation and abandonment, constraints on crop production and crop preferences, (ii) to integrate and compare indigenous knowledge systems with scientific approaches of soil classification and potential, (iii) to determine the effect of climate and soil factors on erodibilities of soils in the Municipality (iv) to delineate arable land and evaluate its suitability for maize, potato, sorghum and cowpea under rainfed agriculture. Using semi-structured and open-ended interviews, information on limitations to crop production, cropping preferences, indigenous soil classifications, cropping potential ratings and erosion was captured. Descriptive and correlation statistics were used to analyse farmers‟ responses. The information was later used for a pilot participatory mapping and the determination of the agricultural potential of the soils in three selected villages of the Municipality. Field boundaries of soil texture, colour, depth, and slope position were captured using global positioning systems (GPS). The relationship between the degree of erosion and soil and slope factors was analysed by step-wise regression. Crop suitability for rainfed agriculture was done using the FAO guidelines for Land evaluation for rainfed agriculture. The spatially referenced crop suitability classes were produced by applying the Law of Limiting Combinationusing GIS Boolean Logic. The major biophysical factors, affecting crop production and land utilisation were soil degradation and low and erratic rainfall, while other factors included lack of farming equipment and security concerns. Maize, spinach and cabbage were the main crops grown, with maize sorghum and wheat the most abandoned crops. While it was difficult to accurately correlate indigenous classification with international scientific classification, the importance of colour, texture and soil depth for both classification and soil potential, suggests that some form of correlation is possible which enabled communication and other extension information to be conveyed. The shallow and stony soil (urhete) correlated well with the Leptosols in World Reference Base (WRB) or Mispah and shallow Glenrosa soils in the South African system. The red structured clays (umhlaba obomvu) matched the Nitisols in WRB or Shortlands in the South African system. The non-swelling black clayey soils (umhlaba omnyama) matched soils with melanic A horizons in both the WRB and South African soil classification systems. The dongwe and santi soils developed in alluvial sediments belonged to the Dundee, Oakleaf or Augrabies soils in the South African classification system and fluvisols or Cambisols in the WRB system. There was good agreement between farmers assessment of the cropping potential and scientific approaches but scientifically high potential red soils were rated lowly by the farmers due to difficulties in management caused by shortages of farm machinery, especially under dryland farming. Overall, the soil factors affecting erosion were influenced largely by climate, while parent material was also important. Climate had a dominant influence on soil factors most notably fine sand and very fine sand fractions and exchangeable sodium percentage being more important on soil forms occurring in arid and semi-arid climate and less in the sub-humid and humid areas, where clay mineralogy, particularly kaolinite and sesquioxide dominated. Dolerite derived soils were the most stable and should be given the highest priority for cropping development while mudstone and shale derived soils had a lower cropping potential. While slope gradient and length had some effect on soil erosion in arid and semi arid environments its influence was generally overshadowed by soil factors especially in humid zones. Cow pea and sorghum were the most adapted crops in the region while potato and maize were marginally suitable under rainfed agriculture. The study revealed that most adapted crops were not necessarily the most preferred crops by the farmers. A small percentage of the land was delineated as arable and therefore optimisation of this available land should be prioritized.
- Full Text:
- Date Issued: 2014
- Authors: Manyevere, Alen
- Date: 2014
- Subjects: Soils -- Classification -- South Africa -- Eastern Cape , Soil degradation -- South Africa -- Eastern Cape , Ethnoscience -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11965 , http://hdl.handle.net/10353/d1019856 , Soils -- Classification -- South Africa -- Eastern Cape , Soil degradation -- South Africa -- Eastern Cape , Ethnoscience -- South Africa -- Eastern Cape
- Description: Arable crop production in Nkonkobe Municipality is low due to abandonment of potentially productive land and low productivity of the cultivated land. Little attention has been given to farmers perspectives with regards to crop production and land abandonment. Understanding the relationships of indigenous knowledge systems, where local approaches to soil classification, appraisal, use and management and land evaluation, and scientific approaches could be important for the effective use of available soil resources while avoiding those resources that are vulnerable to degradation. In addition, the interactions between soil factors and climate could be useful in understanding the erodibility of soils. The intergration of scientific research and indigenous knowledge systems could help in the identification and delineation of high potential land and on crop suitability evaluation. The objectives of the study were: (i) to determine farmers‟ perspectives with regards to land utilisation and abandonment, constraints on crop production and crop preferences, (ii) to integrate and compare indigenous knowledge systems with scientific approaches of soil classification and potential, (iii) to determine the effect of climate and soil factors on erodibilities of soils in the Municipality (iv) to delineate arable land and evaluate its suitability for maize, potato, sorghum and cowpea under rainfed agriculture. Using semi-structured and open-ended interviews, information on limitations to crop production, cropping preferences, indigenous soil classifications, cropping potential ratings and erosion was captured. Descriptive and correlation statistics were used to analyse farmers‟ responses. The information was later used for a pilot participatory mapping and the determination of the agricultural potential of the soils in three selected villages of the Municipality. Field boundaries of soil texture, colour, depth, and slope position were captured using global positioning systems (GPS). The relationship between the degree of erosion and soil and slope factors was analysed by step-wise regression. Crop suitability for rainfed agriculture was done using the FAO guidelines for Land evaluation for rainfed agriculture. The spatially referenced crop suitability classes were produced by applying the Law of Limiting Combinationusing GIS Boolean Logic. The major biophysical factors, affecting crop production and land utilisation were soil degradation and low and erratic rainfall, while other factors included lack of farming equipment and security concerns. Maize, spinach and cabbage were the main crops grown, with maize sorghum and wheat the most abandoned crops. While it was difficult to accurately correlate indigenous classification with international scientific classification, the importance of colour, texture and soil depth for both classification and soil potential, suggests that some form of correlation is possible which enabled communication and other extension information to be conveyed. The shallow and stony soil (urhete) correlated well with the Leptosols in World Reference Base (WRB) or Mispah and shallow Glenrosa soils in the South African system. The red structured clays (umhlaba obomvu) matched the Nitisols in WRB or Shortlands in the South African system. The non-swelling black clayey soils (umhlaba omnyama) matched soils with melanic A horizons in both the WRB and South African soil classification systems. The dongwe and santi soils developed in alluvial sediments belonged to the Dundee, Oakleaf or Augrabies soils in the South African classification system and fluvisols or Cambisols in the WRB system. There was good agreement between farmers assessment of the cropping potential and scientific approaches but scientifically high potential red soils were rated lowly by the farmers due to difficulties in management caused by shortages of farm machinery, especially under dryland farming. Overall, the soil factors affecting erosion were influenced largely by climate, while parent material was also important. Climate had a dominant influence on soil factors most notably fine sand and very fine sand fractions and exchangeable sodium percentage being more important on soil forms occurring in arid and semi-arid climate and less in the sub-humid and humid areas, where clay mineralogy, particularly kaolinite and sesquioxide dominated. Dolerite derived soils were the most stable and should be given the highest priority for cropping development while mudstone and shale derived soils had a lower cropping potential. While slope gradient and length had some effect on soil erosion in arid and semi arid environments its influence was generally overshadowed by soil factors especially in humid zones. Cow pea and sorghum were the most adapted crops in the region while potato and maize were marginally suitable under rainfed agriculture. The study revealed that most adapted crops were not necessarily the most preferred crops by the farmers. A small percentage of the land was delineated as arable and therefore optimisation of this available land should be prioritized.
- Full Text:
- Date Issued: 2014
An information services framework for commercial extension services
- Authors: Simpson, Antony Paul
- Date: 2014
- Subjects: Agricultural extension work , Business networks , Information resources management
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/8575 , vital:26408
- Description: The first of the eight United Nations Millennium Development Goals for 2015 is to “Eradicate Extreme Poverty and Hunger”. Achieving this goal would be aided by having an effective and productive agricultural community. Agricultural organisations assist producers to be more effective in their operation through Commercial Extension Services (CES). Through CES, producers are advised and educated about new agricultural practices, techniques and products. A key component of CES is the provision of relevant information to producers. The problem this research addressed was that producers experience difficulty in accessing the information they require in a timeous, relevant and personalised manner. No suitable framework was found for agricultural organisations to use when designing and implementing an Information Services Platform. The main research objective was to develop and evaluate an Information Services Framework (ISF) for organisations offering information as a CES. The research methodology used to achieve this objective was Design Science Research (DSR). DSR is an iterative methodology with three cycles, namely the relevance, the design and the rigor cycles. The relevance cycle was used to acquire the information required to inform the design cycle. The information was collected by using literature research and empirical studies. The first study, the Producer Information Requirements Survey (PIRS) sought to determine the information requirements of grain producers and was conducted by interviewing grain producers in the Swartland region of South Africa. The second study, the Internet and Mobile Device Usage Survey (IMDUS) investigated the use of the Internet and mobile devices amongst South African producers by means of a national on-line survey. The quantitative and qualitative results of the analysis were used during the design phase to develop the ISF. The design phase of DSR process led to the creation of an ISF for providing Information as a Service (IaaS) in CES. The framework allows for information services to be provided in a manner and form customised to an individual producer’s preferences. The foundation of the framework is that information can be sourced from various sources, internal or external to the organisation and distributed to producers by using a unified platform. During the research, an agricultural organisation, BKB GrainCo used the proposed ISF to develop an Information Services Platform (ISP) to provide information to its producers. BKB GrainCo’s development process included two evaluations. The first evaluation, the Information Preferences Prototype Survey, was intended to test a key component of the framework, the nformation Preferences Profile. The Information Preferences Profile was conceptualized following the PIRS. In the PIRS it was determined that individual producers would prefer to specify what information they would receive, when they required it and have it delivered by using a medium of their choice. The second evaluation of the design phase was a Usability Study. The Usability Study was intended to test the functionality of the system across various technologies. The rigor cycle, following the implementation of BKB GrainCo’s ISP, contained the main evaluation, the Information Services Platform Evaluation. The evaluation was used to test the impact of BKB GrainCo’s ISP on perception of received service. The evaluation used a standardised version of the standardised SERVQUAL instrument specifically adapted in this research to measure the provision of IaaS. The results obtained during the evaluation indicated that the BKB GrainCo’s Information Services Platform was found to be valued by producers and improved the communication services of agricultural organisations. It was inferred from the successful implementation of BKB GrainCo’s ISP and the positive response from producers, after the evaluations, that the developed ISF was suitable for an agricultural organisation to provide CES. The theoretical contributions included underpinning the concept of CES in terms of stakeholder theory. Its underpinning provides justification for agricultural organisations to improve CES – including the provision of information. A second theoretical contribution was the extension of SERVQUAL as an IS theory by developing and validating a dimension designed to test the provision of IaaS. Providing producers with accurate and reliable personalised information has the capacity to improve producers’ ability to make informed decisions. Informed decision making will contribute to having an effective and productive agricultural community; resulting in improvement of agricultural output and contributing to food security and job creation. Improved agricultural output, better food security and job creation are aspects which will contribute toward the attainment of the first of eight United Nations Millennium Development Goals for 2015, which is to “Eradicate Extreme Poverty and Hunger”.
- Full Text:
- Date Issued: 2014
- Authors: Simpson, Antony Paul
- Date: 2014
- Subjects: Agricultural extension work , Business networks , Information resources management
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/8575 , vital:26408
- Description: The first of the eight United Nations Millennium Development Goals for 2015 is to “Eradicate Extreme Poverty and Hunger”. Achieving this goal would be aided by having an effective and productive agricultural community. Agricultural organisations assist producers to be more effective in their operation through Commercial Extension Services (CES). Through CES, producers are advised and educated about new agricultural practices, techniques and products. A key component of CES is the provision of relevant information to producers. The problem this research addressed was that producers experience difficulty in accessing the information they require in a timeous, relevant and personalised manner. No suitable framework was found for agricultural organisations to use when designing and implementing an Information Services Platform. The main research objective was to develop and evaluate an Information Services Framework (ISF) for organisations offering information as a CES. The research methodology used to achieve this objective was Design Science Research (DSR). DSR is an iterative methodology with three cycles, namely the relevance, the design and the rigor cycles. The relevance cycle was used to acquire the information required to inform the design cycle. The information was collected by using literature research and empirical studies. The first study, the Producer Information Requirements Survey (PIRS) sought to determine the information requirements of grain producers and was conducted by interviewing grain producers in the Swartland region of South Africa. The second study, the Internet and Mobile Device Usage Survey (IMDUS) investigated the use of the Internet and mobile devices amongst South African producers by means of a national on-line survey. The quantitative and qualitative results of the analysis were used during the design phase to develop the ISF. The design phase of DSR process led to the creation of an ISF for providing Information as a Service (IaaS) in CES. The framework allows for information services to be provided in a manner and form customised to an individual producer’s preferences. The foundation of the framework is that information can be sourced from various sources, internal or external to the organisation and distributed to producers by using a unified platform. During the research, an agricultural organisation, BKB GrainCo used the proposed ISF to develop an Information Services Platform (ISP) to provide information to its producers. BKB GrainCo’s development process included two evaluations. The first evaluation, the Information Preferences Prototype Survey, was intended to test a key component of the framework, the nformation Preferences Profile. The Information Preferences Profile was conceptualized following the PIRS. In the PIRS it was determined that individual producers would prefer to specify what information they would receive, when they required it and have it delivered by using a medium of their choice. The second evaluation of the design phase was a Usability Study. The Usability Study was intended to test the functionality of the system across various technologies. The rigor cycle, following the implementation of BKB GrainCo’s ISP, contained the main evaluation, the Information Services Platform Evaluation. The evaluation was used to test the impact of BKB GrainCo’s ISP on perception of received service. The evaluation used a standardised version of the standardised SERVQUAL instrument specifically adapted in this research to measure the provision of IaaS. The results obtained during the evaluation indicated that the BKB GrainCo’s Information Services Platform was found to be valued by producers and improved the communication services of agricultural organisations. It was inferred from the successful implementation of BKB GrainCo’s ISP and the positive response from producers, after the evaluations, that the developed ISF was suitable for an agricultural organisation to provide CES. The theoretical contributions included underpinning the concept of CES in terms of stakeholder theory. Its underpinning provides justification for agricultural organisations to improve CES – including the provision of information. A second theoretical contribution was the extension of SERVQUAL as an IS theory by developing and validating a dimension designed to test the provision of IaaS. Providing producers with accurate and reliable personalised information has the capacity to improve producers’ ability to make informed decisions. Informed decision making will contribute to having an effective and productive agricultural community; resulting in improvement of agricultural output and contributing to food security and job creation. Improved agricultural output, better food security and job creation are aspects which will contribute toward the attainment of the first of eight United Nations Millennium Development Goals for 2015, which is to “Eradicate Extreme Poverty and Hunger”.
- Full Text:
- Date Issued: 2014