A colorimetric probe for dopamine based on gold nanoparticles-electrospun nanofibre composite
- Ngomane, Nokuthula, Torto, Nelson, Krause, Rui W M, Vilakazi, Sibulelo
- Authors: Ngomane, Nokuthula , Torto, Nelson , Krause, Rui W M , Vilakazi, Sibulelo
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/195407 , vital:45562 , xlink:href="https://doi.org/10.1016/j.matpr.2015.08.036"
- Description: An easily prepared solid state colorimetric probe for detecting the neurotransmitter dopamine (DA) was developed. The probe, in the form of an electrospun Nylon−6 (N6) nanofibre with embedded un−functionalized gold nanoparticles (UF−AuNPs) produces a clear colour change in the presence of a DA that is detectable by the naked eye. Characterisation of the nanofibre using UV/vis spectroscopy and electron microscopy (TEM) confirmed the formation of the AuNPs in the polymer solution, and that the AuNPs were completely encapsulated within the composite nanofibres before exposure to the analytes. The probe exhibited very high sensitivity towards DA resulting in colour change of the composite fibres from purple to navy blue/black even under low concentrations of DA. The probe was also selective to DA since the colour remained unchanged in the presence of commonly encountered interfering species such as ascorbic acid, uric acid, catechol, epinephrine and norepinephrine. Moreover, the colour change was observed rapid, occurring either immediately on contact with higher concentrations (5 x10−4 M) or within about 3−5 min for the lower concentrations (e.g. 5 x10−7 M). Since this probe does not require the use of any instruments, and is both rapid and stable over time, it can be applied in the field by an inexperienced person.
- Full Text:
- Date Issued: 2015
- Authors: Ngomane, Nokuthula , Torto, Nelson , Krause, Rui W M , Vilakazi, Sibulelo
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/195407 , vital:45562 , xlink:href="https://doi.org/10.1016/j.matpr.2015.08.036"
- Description: An easily prepared solid state colorimetric probe for detecting the neurotransmitter dopamine (DA) was developed. The probe, in the form of an electrospun Nylon−6 (N6) nanofibre with embedded un−functionalized gold nanoparticles (UF−AuNPs) produces a clear colour change in the presence of a DA that is detectable by the naked eye. Characterisation of the nanofibre using UV/vis spectroscopy and electron microscopy (TEM) confirmed the formation of the AuNPs in the polymer solution, and that the AuNPs were completely encapsulated within the composite nanofibres before exposure to the analytes. The probe exhibited very high sensitivity towards DA resulting in colour change of the composite fibres from purple to navy blue/black even under low concentrations of DA. The probe was also selective to DA since the colour remained unchanged in the presence of commonly encountered interfering species such as ascorbic acid, uric acid, catechol, epinephrine and norepinephrine. Moreover, the colour change was observed rapid, occurring either immediately on contact with higher concentrations (5 x10−4 M) or within about 3−5 min for the lower concentrations (e.g. 5 x10−7 M). Since this probe does not require the use of any instruments, and is both rapid and stable over time, it can be applied in the field by an inexperienced person.
- Full Text:
- Date Issued: 2015
Agreement and coordination in XiTsonga, SeSotho and IsiXhosa: an optimality theoretic perspective
- Authors: Mitchley, Hazel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3423 , vital:20491
- Description: This thesis provides a unified Optimality Theoretic analysis of subject-verb agreement with coordinated preverbal subjects in three Southern Bantu languages: Xitsonga (S53), Sesotho (S33), and isiXhosa (S41). This analysis is then used to formulate a typology of agreement resolution strategies and the contexts which trigger them. Although some accounts in the Bantu literature suggest that agreement with coordinate structures is avoided by speakers (e.g. Schadeberg 1992, Voeltz 1971) especially when conjuncts are from different noun classes, I show that there is ample evidence to the contrary, and that the subject marker used is dependent on several factors, including (i) the [-HUMAN] specification on the conjuncts, (ii) whether the conjuncts are singular or plural, (iii) whether or not the conjuncts both carry the same noun class feature, and (iv) the order of the conjuncts. This thesis shows that there are various agreement resolution strategies which can beused: 1) agreement with the [+HUMAN] feature on the conjuncts, 2) agreement with the[-HUMAN] feature on the conjuncts, 3) agreement with the noun class feature on both conjuncts, 4) agreement with the noun class feature on the conjunct closest to the verb, and 5) agreement with the noun class feature on the conjunct furthest from the verb. Not all of these strategies are used by all languages, nor are these strategies interchangeable in the languages which do use them – instead, multiple factors conspire to trigger the use of a specific agreement strategy within a specific agreement featural context. I show that these effects can be captured using Optimality Theory (Prince and Smolensky 2004). The analysis makes use of seven constraints: RES#, MAX[+H], MAX[-H], DEP[-H], MAXNC, DEPNC, and AGREECLOSEST. The hierarchical ranking of these constraints not only accounts for the confinement of particular strategies to specific agreement featural contexts within a language, but also accounts for the cross-linguistic differences in the use of these strategies. I end off by examining the typological implications which follow from the OT analysis provided in this thesis.
- Full Text:
- Date Issued: 2016
- Authors: Mitchley, Hazel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3423 , vital:20491
- Description: This thesis provides a unified Optimality Theoretic analysis of subject-verb agreement with coordinated preverbal subjects in three Southern Bantu languages: Xitsonga (S53), Sesotho (S33), and isiXhosa (S41). This analysis is then used to formulate a typology of agreement resolution strategies and the contexts which trigger them. Although some accounts in the Bantu literature suggest that agreement with coordinate structures is avoided by speakers (e.g. Schadeberg 1992, Voeltz 1971) especially when conjuncts are from different noun classes, I show that there is ample evidence to the contrary, and that the subject marker used is dependent on several factors, including (i) the [-HUMAN] specification on the conjuncts, (ii) whether the conjuncts are singular or plural, (iii) whether or not the conjuncts both carry the same noun class feature, and (iv) the order of the conjuncts. This thesis shows that there are various agreement resolution strategies which can beused: 1) agreement with the [+HUMAN] feature on the conjuncts, 2) agreement with the[-HUMAN] feature on the conjuncts, 3) agreement with the noun class feature on both conjuncts, 4) agreement with the noun class feature on the conjunct closest to the verb, and 5) agreement with the noun class feature on the conjunct furthest from the verb. Not all of these strategies are used by all languages, nor are these strategies interchangeable in the languages which do use them – instead, multiple factors conspire to trigger the use of a specific agreement strategy within a specific agreement featural context. I show that these effects can be captured using Optimality Theory (Prince and Smolensky 2004). The analysis makes use of seven constraints: RES#, MAX[+H], MAX[-H], DEP[-H], MAXNC, DEPNC, and AGREECLOSEST. The hierarchical ranking of these constraints not only accounts for the confinement of particular strategies to specific agreement featural contexts within a language, but also accounts for the cross-linguistic differences in the use of these strategies. I end off by examining the typological implications which follow from the OT analysis provided in this thesis.
- Full Text:
- Date Issued: 2016
The Socio-Economics of boat-based whale-watching in Plettenberg Bay
- Authors: Klaas, Zongezile
- Date: 2020
- Subjects: Whale watching -- South Africa -- Western Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/48676 , vital:41058
- Description: Boat-based whale watching has been gaining momentum since its inception back in the 1950s. Global trends of the marine leisure activity continue to grow at a rapid rate and the African continent has also joined the marine tourism trend in exploring its marine sector to meet its socio-economic challenges. South Africa as one of Africa’s economic giants has also sought a development approach with a focus on utilising its marine and maritime resources to grow the economy in meeting the domestic development objectives. The South African government through the Operation Phakisa come up with a development strategy to revitalise and explore its marine and maritime sectors to fast-track its growth potential in meeting the local developmental objectives. Plettenberg Bay in the Western Cape of South Africa is well-known for its boat-based whale watching service that offers a great experience for both domestic and foreign tourists and its services form part of the Operation Phakisa programme that is aimed at economic growth and development that is focused especially on the previously disadvantaged majority to ensure that their standards of living improve. Looking into the socio-economic effects of boat-based whale watching on low-income households in Plettenberg Bay, gives meaning to finding linkages through indirect relationships between the marine environment and human lives. This therefore fosters an in-depth understanding of how to address social and economic issues in relation to a resource through the utilisation of available assets to meet sustainable development objectives. The aim of the research study is to find the linkages between boat-based whale watching as an industry with how it relates to building resilience for the low-income households in Plettenberg Bay. The study’s importance will be its ability to inform policy decisions, on adopting knowledge-based adaptive strategies and approaches to finding solutions on building resilience for low-income household through the utilisation of boat-based whale watching as a catalyst for development. The information from the research study can be utilised as a tool to empower low-income households on coastal areas, to become active participants in economic activities that are indirectly linked to boat-based whale watching industry for their own development.
- Full Text:
- Date Issued: 2020
- Authors: Klaas, Zongezile
- Date: 2020
- Subjects: Whale watching -- South Africa -- Western Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/48676 , vital:41058
- Description: Boat-based whale watching has been gaining momentum since its inception back in the 1950s. Global trends of the marine leisure activity continue to grow at a rapid rate and the African continent has also joined the marine tourism trend in exploring its marine sector to meet its socio-economic challenges. South Africa as one of Africa’s economic giants has also sought a development approach with a focus on utilising its marine and maritime resources to grow the economy in meeting the domestic development objectives. The South African government through the Operation Phakisa come up with a development strategy to revitalise and explore its marine and maritime sectors to fast-track its growth potential in meeting the local developmental objectives. Plettenberg Bay in the Western Cape of South Africa is well-known for its boat-based whale watching service that offers a great experience for both domestic and foreign tourists and its services form part of the Operation Phakisa programme that is aimed at economic growth and development that is focused especially on the previously disadvantaged majority to ensure that their standards of living improve. Looking into the socio-economic effects of boat-based whale watching on low-income households in Plettenberg Bay, gives meaning to finding linkages through indirect relationships between the marine environment and human lives. This therefore fosters an in-depth understanding of how to address social and economic issues in relation to a resource through the utilisation of available assets to meet sustainable development objectives. The aim of the research study is to find the linkages between boat-based whale watching as an industry with how it relates to building resilience for the low-income households in Plettenberg Bay. The study’s importance will be its ability to inform policy decisions, on adopting knowledge-based adaptive strategies and approaches to finding solutions on building resilience for low-income household through the utilisation of boat-based whale watching as a catalyst for development. The information from the research study can be utilised as a tool to empower low-income households on coastal areas, to become active participants in economic activities that are indirectly linked to boat-based whale watching industry for their own development.
- Full Text:
- Date Issued: 2020
Oomashayela phezulu:
- Mazibuko, Nokuthula, Kaschula, Russell H
- Authors: Mazibuko, Nokuthula , Kaschula, Russell H
- Date: 2004
- Language: Zulu
- Type: text , book
- Identifier: http://hdl.handle.net/10962/175323 , vital:42565 , ISBN 9781869284251
- Description: ‘Sam, khawuphole maan, thob'umoya. KungoLwesihlanu namhlanje, sakuba nalo ithuba elininzi ngomso lokuzithethelela ebazalini bethu! Ha, ha, ha!'wagigitheka uBrunette'Thatha nantsi icider, usele!'UBrunette wayonwabile, wayekuthanda futhi ekonwabela ngoku ukusela, kwaye ezi iicider zazingavakali ngathi butywala! Wayeziva efanelekile kwibhulukhwe yakhe ebomvu, ethe nca kuye emzimbeni kakuhle, nehempe awayeyinxibe ngentla ehambelana nayo, nezihlangu ezichophileyo awayezinxibile. Wagqiba kwangexesha ukuphotha iinwele zakhe ngoboya bomsila wehashe, elungele ipati eyayiza kuba ngobo busuku. Yayintle into yokuba abe woluka iinwele zabantu. Ngokwenza njalo wayezenzela.
- Full Text:
- Date Issued: 2004
- Authors: Mazibuko, Nokuthula , Kaschula, Russell H
- Date: 2004
- Language: Zulu
- Type: text , book
- Identifier: http://hdl.handle.net/10962/175323 , vital:42565 , ISBN 9781869284251
- Description: ‘Sam, khawuphole maan, thob'umoya. KungoLwesihlanu namhlanje, sakuba nalo ithuba elininzi ngomso lokuzithethelela ebazalini bethu! Ha, ha, ha!'wagigitheka uBrunette'Thatha nantsi icider, usele!'UBrunette wayonwabile, wayekuthanda futhi ekonwabela ngoku ukusela, kwaye ezi iicider zazingavakali ngathi butywala! Wayeziva efanelekile kwibhulukhwe yakhe ebomvu, ethe nca kuye emzimbeni kakuhle, nehempe awayeyinxibe ngentla ehambelana nayo, nezihlangu ezichophileyo awayezinxibile. Wagqiba kwangexesha ukuphotha iinwele zakhe ngoboya bomsila wehashe, elungele ipati eyayiza kuba ngobo busuku. Yayintle into yokuba abe woluka iinwele zabantu. Ngokwenza njalo wayezenzela.
- Full Text:
- Date Issued: 2004
Un-functionalized gold nanoparticles as a simple colorimetric probe for sensitive and selective detection of dopamine
- Khanyile, Nokuthula, Krause, Rui W M, Vilakazi, Sibulelo, Torto, Nelson
- Authors: Khanyile, Nokuthula , Krause, Rui W M , Vilakazi, Sibulelo , Torto, Nelson
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/195048 , vital:45522 , xlink:href="http://dx.doi.org/10.17159/0379-4350/2019/v72a27"
- Description: A dopamine (DA) colorimetric probe based on the growth and aggregation of un-functionalized gold nanoparticles (AuNPs) is reported. Upon addition of AuNPs to dopamine at various concentrations, the shape, size and colour change of the nanoparticles results in spectral shifts to higher wavelengths and hence colour change is the mode of detection. The colour change can be easily observed by the naked eye from as low as 5.0 nM DA, even under sub-optimal conditions. Under optimal pH conditions the calculated limit of detection was 2.5 nM (3σ). The probe was successfully applied to whole blood sample and showed good selectivity and sensitivity towards DA. The simple, sensitive and selective probe could be an excellent alternative for on-site and immediate detection of DA without the use of instrumentation and would thus be useful for rapid diagnostic applications.
- Full Text:
- Date Issued: 2019
- Authors: Khanyile, Nokuthula , Krause, Rui W M , Vilakazi, Sibulelo , Torto, Nelson
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/195048 , vital:45522 , xlink:href="http://dx.doi.org/10.17159/0379-4350/2019/v72a27"
- Description: A dopamine (DA) colorimetric probe based on the growth and aggregation of un-functionalized gold nanoparticles (AuNPs) is reported. Upon addition of AuNPs to dopamine at various concentrations, the shape, size and colour change of the nanoparticles results in spectral shifts to higher wavelengths and hence colour change is the mode of detection. The colour change can be easily observed by the naked eye from as low as 5.0 nM DA, even under sub-optimal conditions. Under optimal pH conditions the calculated limit of detection was 2.5 nM (3σ). The probe was successfully applied to whole blood sample and showed good selectivity and sensitivity towards DA. The simple, sensitive and selective probe could be an excellent alternative for on-site and immediate detection of DA without the use of instrumentation and would thus be useful for rapid diagnostic applications.
- Full Text:
- Date Issued: 2019
Electrospun sorbents for solid phase extraction (SPE) and colorimetric detection of pesticides
- Authors: Gulamussen, Noor Jehan
- Date: 2014
- Subjects: Sorbents , Electrospinning , Extraction (Chemistry) , Colorimetry , Pesticides , Water -- Pesticide content -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4501 , http://hdl.handle.net/10962/d1013241
- Description: The thesis presents the evaluation of polysulfone sorbents for solid phase extraction (SPE) and the development of colorimetric probes for pesticides analysis in water. Through electrospraying and electrospinning techniques, different morphologies of sorbents (particles, beaded fibers and bead-free fibers) were fabricated. The sorbents were morphologically characterized by scanning electron microscopy. Adsorption capacities of sorbents were evaluated by conducting recoveries studies for model pesticides; atrazine, chlorpyrifos and DDT using batch and column SPE modes. Better recovery results were achieved by employing the batch mode of fibers, as values ranged from 98 to 105percent. Further sorbent evaluation was conducted using breakthrough experiments and static experiments. The breakthrough studies indicated that 1700 μL was the sample volume that could be percolated with no breakthrough of the analyte that correspond to a concentration of 150 mg/g of sorbent that can be extracted without any loss of analyte. From static studies, quantities of each model compound adsorbed into the fiber at the equilibrium time were evaluated. The adsorbed atrazine was 65, chlorpyrifos 250 and DDT 400 mg/g of sorbent. Kinetic studies suggested retention mechanism following pseudo first and second order model observed by high correlation coefficients (> 0. 96), demonstrating the fiber affinity to retain both polar and non-polar compounds opening a possibility to be used as sorbent for sample preparation of different classes of pesticides in water. For the second part of the study simple strategies for colorimetric sensing based on silver nanoparticles and polivinylpyrrolidone capped nanoparticles were developed, respectively for atrazine and chlorpyrifos detection. The limits of detection of the methods were 3.32 and 0.88 mg/L for atrazine and chlorpyrifos respectively. The applicability of the probe in real samples was demonstrated by the recoveries studies of tap water varying from 94 to 104 percent. The versatility of the probe was demonstrated by affording a simple, rapid and selective detection of atrazine and chlorpyrifos in the presence of other pesticides by direct analysis without employing any sample handling steps. Attempt to incorporate the probes in a solid support was achieved by using nylon 6 as solid support polymer proving to be fast and useful for on-site detection.
- Full Text:
- Date Issued: 2014
- Authors: Gulamussen, Noor Jehan
- Date: 2014
- Subjects: Sorbents , Electrospinning , Extraction (Chemistry) , Colorimetry , Pesticides , Water -- Pesticide content -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4501 , http://hdl.handle.net/10962/d1013241
- Description: The thesis presents the evaluation of polysulfone sorbents for solid phase extraction (SPE) and the development of colorimetric probes for pesticides analysis in water. Through electrospraying and electrospinning techniques, different morphologies of sorbents (particles, beaded fibers and bead-free fibers) were fabricated. The sorbents were morphologically characterized by scanning electron microscopy. Adsorption capacities of sorbents were evaluated by conducting recoveries studies for model pesticides; atrazine, chlorpyrifos and DDT using batch and column SPE modes. Better recovery results were achieved by employing the batch mode of fibers, as values ranged from 98 to 105percent. Further sorbent evaluation was conducted using breakthrough experiments and static experiments. The breakthrough studies indicated that 1700 μL was the sample volume that could be percolated with no breakthrough of the analyte that correspond to a concentration of 150 mg/g of sorbent that can be extracted without any loss of analyte. From static studies, quantities of each model compound adsorbed into the fiber at the equilibrium time were evaluated. The adsorbed atrazine was 65, chlorpyrifos 250 and DDT 400 mg/g of sorbent. Kinetic studies suggested retention mechanism following pseudo first and second order model observed by high correlation coefficients (> 0. 96), demonstrating the fiber affinity to retain both polar and non-polar compounds opening a possibility to be used as sorbent for sample preparation of different classes of pesticides in water. For the second part of the study simple strategies for colorimetric sensing based on silver nanoparticles and polivinylpyrrolidone capped nanoparticles were developed, respectively for atrazine and chlorpyrifos detection. The limits of detection of the methods were 3.32 and 0.88 mg/L for atrazine and chlorpyrifos respectively. The applicability of the probe in real samples was demonstrated by the recoveries studies of tap water varying from 94 to 104 percent. The versatility of the probe was demonstrated by affording a simple, rapid and selective detection of atrazine and chlorpyrifos in the presence of other pesticides by direct analysis without employing any sample handling steps. Attempt to incorporate the probes in a solid support was achieved by using nylon 6 as solid support polymer proving to be fast and useful for on-site detection.
- Full Text:
- Date Issued: 2014
An assessment of municipal performance assessment system as a tool to improve performance in Ngqushwa local municipality in the Eastern Cape
- Authors: Batayi, Nokuthula
- Date: 2017
- Subjects: Performance -- Evaluation Local government -- South Africa -- Eastern Cape Public administration -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10353/13436 , vital:39661
- Description: Monitoring and evaluation is a key contributing factor in the accomplishment of the vision, mission and strategic goals of the department. It is an on-going communication, undertaken in partnership between employees and their immediate supervisors. This research study focused on assessing the performance management system as a tool to improve performance in Ngqushwa Local Municipality. It has been found that Ngqushwa Local Municipality has undertaken measures to implement the performance management system which is aligned with legislative frameworks i.e. Republic of South African Constitution of 1996, Municipal Systems Act 32 of 2000, Municipal Structures Act 117 of 1998, Municipal Finance Management Act 56 of 2003, Public Service Regulation 2001, and Monitoring and Evaluation Frameworks. However, the research findings showed that such efforts were not sufficient in terms of implementation of Performance Management System. The study suggested that 1) the system should also accommodate employees who are in lower levels as way to strengthen the implementation of the system; 2) Involvement of stakeholders should be prioritised so as to promote ownership of the system 3) Continuous training of employees and feedback should also be considered.
- Full Text:
- Date Issued: 2017
- Authors: Batayi, Nokuthula
- Date: 2017
- Subjects: Performance -- Evaluation Local government -- South Africa -- Eastern Cape Public administration -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10353/13436 , vital:39661
- Description: Monitoring and evaluation is a key contributing factor in the accomplishment of the vision, mission and strategic goals of the department. It is an on-going communication, undertaken in partnership between employees and their immediate supervisors. This research study focused on assessing the performance management system as a tool to improve performance in Ngqushwa Local Municipality. It has been found that Ngqushwa Local Municipality has undertaken measures to implement the performance management system which is aligned with legislative frameworks i.e. Republic of South African Constitution of 1996, Municipal Systems Act 32 of 2000, Municipal Structures Act 117 of 1998, Municipal Finance Management Act 56 of 2003, Public Service Regulation 2001, and Monitoring and Evaluation Frameworks. However, the research findings showed that such efforts were not sufficient in terms of implementation of Performance Management System. The study suggested that 1) the system should also accommodate employees who are in lower levels as way to strengthen the implementation of the system; 2) Involvement of stakeholders should be prioritised so as to promote ownership of the system 3) Continuous training of employees and feedback should also be considered.
- Full Text:
- Date Issued: 2017
The non-restoration of land: scope and ambit of section 34 of the restitution of land rights act
- Authors: Christoffels, Eugene Miles
- Date: 2018
- Subjects: Restitution -- South Africa , Land reform -- South Africa Land reform -- Government policy -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: http://hdl.handle.net/10948/23869 , vital:30636
- Description: The land question is an emotionally-laden issue for all people across the racial divide in South Africa, albeit for different reasons land serves a variety of human needs: it creates a sense of identity, it creates wealth, imbues the owner with human dignity; it is also an axis for social cohesion and it is key to the exercise of economic and political power. South Africa is still in the throes of withdrawal symptoms as a result of a checkered colonial past, when it comes to the issue of the land. Having been dispossessed of their ancestral land by the country’s former colonial rulers, the majority of South Africans now have the yearning that the wrongs of the past be addressed, and that justice be done. Having repealed the Apartheid laws which had provided for the calculated systematic dispossession of the land and rights in land of the majority of citizens of South Africa, was and is not sufficient. The Constitution of the Republic of South Africa, being negotiated Constitution, which is internationally lauded, provides for a three-pronged land reform programme, namely restitution, redistribution and tenure reform. The focus of this dissertation is on the restitution leg and more specifically the issue of non-restoration which is provided for in section 34 of the RLRA 22 of 1994, as amended (the RLRA). Section 34 specifically provides that in some instances, land will not be restored to claimants even though they may satisfy the requirements for a valid claim provided for in section 25(7) of the Constitution and section 2 of the RLRA. It is submitted that it is necessary to acquire an understanding of the requirements for a restitution claim even though the land claimed may be removed from the process before a claim has been finalised, since the claimants will still have to satisfy the abovementioned requirements after a particular parcel of land or right in land has been removed from the process by a court of law. In other words, the court has made an order of non-restoration even before the claim has been finalised. Such an application for non-restoration of the land in question or rights in relation to land, may be brought by any national, provincial or local government body, in terms of section 34(1) of the RLRA, and the court will then grant such application provided the applicant has convinced the court that the two threshold requirements listed in section 34(6) have been satisfied. This dissertation outlines a number of cases which serve as practical examples of how the courts dealt with the threshold requirements contained in section 34(6). Included in this examination is the courts’ interpretation of the concepts “public interest” and “substantial prejudice”, which are contained in the requirements listed in section 34(6). This dissertation furthermore sought to determine whether the courts have adopted a broad or narrow approach to these concepts and whether the approach that the courts have adopted strikes an appropriate balance between the constitutional right to restitution and the goals underlying section 34. What is evident from the research is that, apart from the Constitutional Court in the KwaLindile case, none of the other courts provided a substantive definition of the concept “public interest”, but rather chose to refer to academic writings. It is submitted that the courts by and large appear to overlook the fact that the restitution of land and rights in land and arguably, the restoration of land, are in the public interest. While the courts do acknowledge the claimants’ rights to restitution, they downplay the importance of restoration since they argue that there is only a right to restitution and not a right to restoration, and that claimants can still be offered an alternative remedy in lieu of restoration, and in the process courts are ignorant of the fact that these other remedies do not help to change the skewed racial distribution of land in South Africa. Two factors seem to weigh heavily with the courts in favouring the granting of a section 34 order, it being the development of the land or development potential and the avoidance of the cost of a lengthy trial focusing on the restoration when there is no chance of success. It is submitted that there seems to be an over-emphasis on these factors while ignoring the fact that a person’s house is part of his identity, deserving more protection than other property, such as a shopping centre, which is not constitutive of a person’s identity. This view is espoused by Radin. Dyal-Chand postulates the idea that property is not always exclusive but can be shared. This would mean that when it comes to property like shopping centres, which she regards as quasi-public property, the courts should be more willing to grant restoration orders and thus not be so willing to grant section 34 non-restoration orders. Even though the RLRA, through section 34(5)(c) gives the courts the power to transform our colonial system of property law, it is submitted that they have largely failed to rise to this challenge. There appears to be an unwillingness to make a shift from our Roman-Dutch law past and break with our Eurocentric view of property law.
- Full Text:
- Date Issued: 2018
- Authors: Christoffels, Eugene Miles
- Date: 2018
- Subjects: Restitution -- South Africa , Land reform -- South Africa Land reform -- Government policy -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: http://hdl.handle.net/10948/23869 , vital:30636
- Description: The land question is an emotionally-laden issue for all people across the racial divide in South Africa, albeit for different reasons land serves a variety of human needs: it creates a sense of identity, it creates wealth, imbues the owner with human dignity; it is also an axis for social cohesion and it is key to the exercise of economic and political power. South Africa is still in the throes of withdrawal symptoms as a result of a checkered colonial past, when it comes to the issue of the land. Having been dispossessed of their ancestral land by the country’s former colonial rulers, the majority of South Africans now have the yearning that the wrongs of the past be addressed, and that justice be done. Having repealed the Apartheid laws which had provided for the calculated systematic dispossession of the land and rights in land of the majority of citizens of South Africa, was and is not sufficient. The Constitution of the Republic of South Africa, being negotiated Constitution, which is internationally lauded, provides for a three-pronged land reform programme, namely restitution, redistribution and tenure reform. The focus of this dissertation is on the restitution leg and more specifically the issue of non-restoration which is provided for in section 34 of the RLRA 22 of 1994, as amended (the RLRA). Section 34 specifically provides that in some instances, land will not be restored to claimants even though they may satisfy the requirements for a valid claim provided for in section 25(7) of the Constitution and section 2 of the RLRA. It is submitted that it is necessary to acquire an understanding of the requirements for a restitution claim even though the land claimed may be removed from the process before a claim has been finalised, since the claimants will still have to satisfy the abovementioned requirements after a particular parcel of land or right in land has been removed from the process by a court of law. In other words, the court has made an order of non-restoration even before the claim has been finalised. Such an application for non-restoration of the land in question or rights in relation to land, may be brought by any national, provincial or local government body, in terms of section 34(1) of the RLRA, and the court will then grant such application provided the applicant has convinced the court that the two threshold requirements listed in section 34(6) have been satisfied. This dissertation outlines a number of cases which serve as practical examples of how the courts dealt with the threshold requirements contained in section 34(6). Included in this examination is the courts’ interpretation of the concepts “public interest” and “substantial prejudice”, which are contained in the requirements listed in section 34(6). This dissertation furthermore sought to determine whether the courts have adopted a broad or narrow approach to these concepts and whether the approach that the courts have adopted strikes an appropriate balance between the constitutional right to restitution and the goals underlying section 34. What is evident from the research is that, apart from the Constitutional Court in the KwaLindile case, none of the other courts provided a substantive definition of the concept “public interest”, but rather chose to refer to academic writings. It is submitted that the courts by and large appear to overlook the fact that the restitution of land and rights in land and arguably, the restoration of land, are in the public interest. While the courts do acknowledge the claimants’ rights to restitution, they downplay the importance of restoration since they argue that there is only a right to restitution and not a right to restoration, and that claimants can still be offered an alternative remedy in lieu of restoration, and in the process courts are ignorant of the fact that these other remedies do not help to change the skewed racial distribution of land in South Africa. Two factors seem to weigh heavily with the courts in favouring the granting of a section 34 order, it being the development of the land or development potential and the avoidance of the cost of a lengthy trial focusing on the restoration when there is no chance of success. It is submitted that there seems to be an over-emphasis on these factors while ignoring the fact that a person’s house is part of his identity, deserving more protection than other property, such as a shopping centre, which is not constitutive of a person’s identity. This view is espoused by Radin. Dyal-Chand postulates the idea that property is not always exclusive but can be shared. This would mean that when it comes to property like shopping centres, which she regards as quasi-public property, the courts should be more willing to grant restoration orders and thus not be so willing to grant section 34 non-restoration orders. Even though the RLRA, through section 34(5)(c) gives the courts the power to transform our colonial system of property law, it is submitted that they have largely failed to rise to this challenge. There appears to be an unwillingness to make a shift from our Roman-Dutch law past and break with our Eurocentric view of property law.
- Full Text:
- Date Issued: 2018
Petrographic and geochemical characterisation of the hangingwall and the footwall rocks (the Dipeta and R.A.T. stratigraphic units) to the Kinsevere and Nambulwa copper ore deposits of the Lufilian Arc, southern Democratic Republic of Congo
- Authors: Nkulu, Robert Kankomba
- Date: 2020
- Subjects: Petrogenesis -- Congo (Democratic Republic) , Analytical geochemistry -- Congo (Democratic Republic) , Copper ores -- Congo (Democratic Republic) , Ore deposits -- Congo (Democratic Republic) , Katangan Sequence , Geological mapping -- Congo (Democratic Republic) , Central African Copperbelt (Congo and Zambia) , Lufilian Arc , Neoproterozoic Katangan R.A.T. (Roches Argilo Talqueuse) Subgroup , Dipeta Subgroup
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/142772 , vital:38115
- Description: The Kinsevere and Nambulwa copper deposits in the Democratic Republic of Congo (D.R.C.) are set in the eastern side of the Neoproterozoic Katanga Supergroup, forming the Lufilian Arc, resulting from a cratonic collision between the Congo and the Kalahari Cratons (ca.620-570_Ma). The Katanga Supergroup was deposited in an extensional rift setting with a sedimentary thickness succession ranging between 7 to 10 km, sub-divided into: − the Roan, the Nguba and the Kundelungu Groups. The stratigraphic column of the Roan Group consists of the R.A.T. (Roche Argilo Talqueuse), the Mines, the Dipeta and the Mwashya Subgroups. Three major deformation phases have been described characterised by complex multiphase tectonics related to a curved superposition of folded, thrust and sheared blocks. The rocks of the R.A.T., Mines and Dipeta Subgroups are recognised as blocks that occur within a stratiform to discordant and diapiritic megabreccia. The blocks were rafted upward with salt tectonics, resulting in the juxtaposition with the hangingwall and the footwall terranes. Therefore, in that context it has been found that the Dipeta may appear overlying the R.A.T. Subgroup through the unconformity decollement surface of heterogeneous breccia. The petrographic observations made of the R.A.T. and Dipeta samples indicates in both units the presence of detrital quartz and feldspar that have been altered and replaced by sericite and muscovite minerals. Gypsum is intimately associated with magnesite, showing an evaporitic environment domain, while magnesite is common as alteration phase both in the R.A.T. and Dipeta Subgroups. Pyrophyllite has been observed in the Dipeta, resulting from reaction of silica with the Kaolinite at low temperature. Accessory detrital minerals include zircon, as well as xenotime intergrown with altered Fe-Ti-oxide hematite, forming complex textures with disseminated Ti-oxides both in R.A.T. and Dipeta units. Major and trace element geochemistry indicates that the Dipeta is more dolomitic and magnesite while the R.A.T. is clay-rich. The Ti2O value of Dipeta and R.A.T samples is relatively low, ranging between 0.36 and 0.69 wt.% respectively, which suggest highly evolved felsic material in the protolith. This is consistent with interpretation based on the Al2O3/TiO2 ratio, which ranges between 18 and 23 for the R.A.T. and Dipeta respectively, indicating an intermediate to felsic granitoids as the protolith of R.A.T. and Dipeta siltstones. The Ti/Zr ratio of R.A.T. and Dipeta samples of less than 10, while, the higher La/Sc ratio of between 2.6 and 5.5 (for the R.A.T. and Dipeta respectively) indicate that both the R.A.T. and Dipeta are active continental and passive margin tectonic setting. Based on the geochemical variation with depth across the R.A.T. and Dipeta and their contact zone, a geochemical fingerprinting suggests that the ratio TiO2/Al2O3 appears to be useful and could be considered as a stratigraphic geochemical maker able to discriminate the R.A.T. and the Dipeta Subgroups during the geological mapping.
- Full Text:
- Date Issued: 2020
- Authors: Nkulu, Robert Kankomba
- Date: 2020
- Subjects: Petrogenesis -- Congo (Democratic Republic) , Analytical geochemistry -- Congo (Democratic Republic) , Copper ores -- Congo (Democratic Republic) , Ore deposits -- Congo (Democratic Republic) , Katangan Sequence , Geological mapping -- Congo (Democratic Republic) , Central African Copperbelt (Congo and Zambia) , Lufilian Arc , Neoproterozoic Katangan R.A.T. (Roches Argilo Talqueuse) Subgroup , Dipeta Subgroup
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/142772 , vital:38115
- Description: The Kinsevere and Nambulwa copper deposits in the Democratic Republic of Congo (D.R.C.) are set in the eastern side of the Neoproterozoic Katanga Supergroup, forming the Lufilian Arc, resulting from a cratonic collision between the Congo and the Kalahari Cratons (ca.620-570_Ma). The Katanga Supergroup was deposited in an extensional rift setting with a sedimentary thickness succession ranging between 7 to 10 km, sub-divided into: − the Roan, the Nguba and the Kundelungu Groups. The stratigraphic column of the Roan Group consists of the R.A.T. (Roche Argilo Talqueuse), the Mines, the Dipeta and the Mwashya Subgroups. Three major deformation phases have been described characterised by complex multiphase tectonics related to a curved superposition of folded, thrust and sheared blocks. The rocks of the R.A.T., Mines and Dipeta Subgroups are recognised as blocks that occur within a stratiform to discordant and diapiritic megabreccia. The blocks were rafted upward with salt tectonics, resulting in the juxtaposition with the hangingwall and the footwall terranes. Therefore, in that context it has been found that the Dipeta may appear overlying the R.A.T. Subgroup through the unconformity decollement surface of heterogeneous breccia. The petrographic observations made of the R.A.T. and Dipeta samples indicates in both units the presence of detrital quartz and feldspar that have been altered and replaced by sericite and muscovite minerals. Gypsum is intimately associated with magnesite, showing an evaporitic environment domain, while magnesite is common as alteration phase both in the R.A.T. and Dipeta Subgroups. Pyrophyllite has been observed in the Dipeta, resulting from reaction of silica with the Kaolinite at low temperature. Accessory detrital minerals include zircon, as well as xenotime intergrown with altered Fe-Ti-oxide hematite, forming complex textures with disseminated Ti-oxides both in R.A.T. and Dipeta units. Major and trace element geochemistry indicates that the Dipeta is more dolomitic and magnesite while the R.A.T. is clay-rich. The Ti2O value of Dipeta and R.A.T samples is relatively low, ranging between 0.36 and 0.69 wt.% respectively, which suggest highly evolved felsic material in the protolith. This is consistent with interpretation based on the Al2O3/TiO2 ratio, which ranges between 18 and 23 for the R.A.T. and Dipeta respectively, indicating an intermediate to felsic granitoids as the protolith of R.A.T. and Dipeta siltstones. The Ti/Zr ratio of R.A.T. and Dipeta samples of less than 10, while, the higher La/Sc ratio of between 2.6 and 5.5 (for the R.A.T. and Dipeta respectively) indicate that both the R.A.T. and Dipeta are active continental and passive margin tectonic setting. Based on the geochemical variation with depth across the R.A.T. and Dipeta and their contact zone, a geochemical fingerprinting suggests that the ratio TiO2/Al2O3 appears to be useful and could be considered as a stratigraphic geochemical maker able to discriminate the R.A.T. and the Dipeta Subgroups during the geological mapping.
- Full Text:
- Date Issued: 2020
Synthesis and characterisation of lanthanide complexes with nitrogen- and oxygen-donor ligands
- Authors: Madanhire, Tatenda
- Date: 2016
- Subjects: Rare earth metals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/13127 , vital:27154
- Description: The reactions of Ln(NO3)3∙6H2O (Ln = Pr, Nd or Er) with the potentially tridentate O,N,O chelating ligand 2,6-pyridinedimethanol (H2pydm) were investigated, and complexes with the formula, [Ln(H2pydm)2(NO3)2](NO3) (Ln = Pr or Nd) and [Er(H2pydm)3](NO3)3 were isolated. The ten-coordinate Pr(III) and Nd(III) compounds crystallise in the triclinic space group P-1 while the nine-coordinate Er(III) complex crystallises in the monoclinic system (P21/n). The reaction of PrCl3∙6H2O with H2pydm yielded the compound, [Pr(H2pydm)3](Cl)3, that crystallises in the monoclinic system, space group P21/c with α = 90, β = 98.680(1) and γ = 90°. The nine-coordinate Pr(III) ion is bound to three H2pydm ligands, with bond distances Pr-O 2.455(2)-2.478(2) Å and Pr-N 2.6355(19)-2.64(2) Å. X-ray crystal structures of all the H2pydm complexes reveal that the ligand coordinates tridentately, via the pyridyl nitrogen atom and the two hydroxyl oxygen atoms. The electronic absorption spectra of complexes show 4f-4f transitions. Rare-earth complexes, [Ln(H2L1)2(NO3)3] [Ln = Gd, Ho or Nd], were also prepared from a Schiff base. The X-ray single-crystal diffraction studies and SHAPE analyses of the Gd(III) and Ho(III) complexes shows that the complexes are ten-coordinate and exhibit distorted tetradecahedron geometries. With proton migration occurring from the phenol group to the imine function, complexation of the lanthanides to the ligand gives the ligand a zwitterionic phenoxo-iminium form. A phenolate oxygen-bridged dinuclear complex, [Ce2(H2L1)(ovan)3(NO3)3], has been obtained by reacting Ce(NO3)3∙6H2O with an o-vanillin derived Schiff base ligand, 2-((E)-(1-hydroxy-2-methylpropan-2-ylimino)methyl)-6-methoxyphenol (H2L1). Hydrolysis of the Schiff base occurred to yield o-vanillin, which bridged two cerium atoms with the Ce∙∙∙Ce distance equal to 3.823 Å. The Ce(III) ions are both tencoordinate, but have different coordination environments, showing tetradecahedron and staggered dodecahedron geometries, respectively. The reaction of salicylaldehyde-N(4)-diethylthiosemicarbazone (H2L2) in the presence of hydrated Ln(III) nitrates led to the isolation of two novel compounds: (E)-2[(ortho-hydroxy)benzylidene]-2-(thiomethyl)-thionohydrazide (1) and bis[2,3-diaza4-(2-hydroxyphenyl)-1-thiomethyl-buta-1,3-diene]disulfide. The latter is a dimer of the former. For this asymmetric Schiff base, 1 and the symmetric disulfide, classical hydrogen bonds of the O–H∙∙∙N as well as N–H∙∙∙S (for 1) type are apparent next to C–H∙∙∙O contacts. 4-(4-Bromophenyl)-1-(propan-2-ylidene)thiosemicarbazide was also prepared upon reacting 4-(4-bromophenyl)-3-thiosemicarbazide with acetone in the presence of ethanol and La(NO3)3∙6H2O. The C=S bond length was found to be 1.6686(16) Å which is in good agreement with other thioketones whose metrical parameters have been deposited with the Cambridge Structural Database. Classical hydrogen bonds of the N–H∙∙∙N and the N–H∙∙∙Br type are observed next to C–H∙∙∙S contacts. All synthesised compounds were characterised by microanalyses, single-crystal X-ray diffraction (except for [Nd(H2L1)2(NO3)3]), 1H NMR and IR spectroscopy.
- Full Text:
- Date Issued: 2016
- Authors: Madanhire, Tatenda
- Date: 2016
- Subjects: Rare earth metals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/13127 , vital:27154
- Description: The reactions of Ln(NO3)3∙6H2O (Ln = Pr, Nd or Er) with the potentially tridentate O,N,O chelating ligand 2,6-pyridinedimethanol (H2pydm) were investigated, and complexes with the formula, [Ln(H2pydm)2(NO3)2](NO3) (Ln = Pr or Nd) and [Er(H2pydm)3](NO3)3 were isolated. The ten-coordinate Pr(III) and Nd(III) compounds crystallise in the triclinic space group P-1 while the nine-coordinate Er(III) complex crystallises in the monoclinic system (P21/n). The reaction of PrCl3∙6H2O with H2pydm yielded the compound, [Pr(H2pydm)3](Cl)3, that crystallises in the monoclinic system, space group P21/c with α = 90, β = 98.680(1) and γ = 90°. The nine-coordinate Pr(III) ion is bound to three H2pydm ligands, with bond distances Pr-O 2.455(2)-2.478(2) Å and Pr-N 2.6355(19)-2.64(2) Å. X-ray crystal structures of all the H2pydm complexes reveal that the ligand coordinates tridentately, via the pyridyl nitrogen atom and the two hydroxyl oxygen atoms. The electronic absorption spectra of complexes show 4f-4f transitions. Rare-earth complexes, [Ln(H2L1)2(NO3)3] [Ln = Gd, Ho or Nd], were also prepared from a Schiff base. The X-ray single-crystal diffraction studies and SHAPE analyses of the Gd(III) and Ho(III) complexes shows that the complexes are ten-coordinate and exhibit distorted tetradecahedron geometries. With proton migration occurring from the phenol group to the imine function, complexation of the lanthanides to the ligand gives the ligand a zwitterionic phenoxo-iminium form. A phenolate oxygen-bridged dinuclear complex, [Ce2(H2L1)(ovan)3(NO3)3], has been obtained by reacting Ce(NO3)3∙6H2O with an o-vanillin derived Schiff base ligand, 2-((E)-(1-hydroxy-2-methylpropan-2-ylimino)methyl)-6-methoxyphenol (H2L1). Hydrolysis of the Schiff base occurred to yield o-vanillin, which bridged two cerium atoms with the Ce∙∙∙Ce distance equal to 3.823 Å. The Ce(III) ions are both tencoordinate, but have different coordination environments, showing tetradecahedron and staggered dodecahedron geometries, respectively. The reaction of salicylaldehyde-N(4)-diethylthiosemicarbazone (H2L2) in the presence of hydrated Ln(III) nitrates led to the isolation of two novel compounds: (E)-2[(ortho-hydroxy)benzylidene]-2-(thiomethyl)-thionohydrazide (1) and bis[2,3-diaza4-(2-hydroxyphenyl)-1-thiomethyl-buta-1,3-diene]disulfide. The latter is a dimer of the former. For this asymmetric Schiff base, 1 and the symmetric disulfide, classical hydrogen bonds of the O–H∙∙∙N as well as N–H∙∙∙S (for 1) type are apparent next to C–H∙∙∙O contacts. 4-(4-Bromophenyl)-1-(propan-2-ylidene)thiosemicarbazide was also prepared upon reacting 4-(4-bromophenyl)-3-thiosemicarbazide with acetone in the presence of ethanol and La(NO3)3∙6H2O. The C=S bond length was found to be 1.6686(16) Å which is in good agreement with other thioketones whose metrical parameters have been deposited with the Cambridge Structural Database. Classical hydrogen bonds of the N–H∙∙∙N and the N–H∙∙∙Br type are observed next to C–H∙∙∙S contacts. All synthesised compounds were characterised by microanalyses, single-crystal X-ray diffraction (except for [Nd(H2L1)2(NO3)3]), 1H NMR and IR spectroscopy.
- Full Text:
- Date Issued: 2016
Factors Influencing Enrolment In Rural Primary Schools In One Circuit, Port St. Johns Cmc, Or Tambo Coastal Education District
- Authors: Lungu, Simlindile Humphrey
- Date: 2020
- Subjects: Collaboration, school culture, school merger, rationalisation, educator attrition, enrolment, rural, educators, learners.
- Language: English
- Type: Masters , Master of Education (M. Ed)
- Identifier: http://hdl.handle.net/11260/6244 , vital:45343
- Description: The purpose of this study was to investigate the factors influencing enrolment in rural primary schools in one Circuit in Port St. Johns CMC in OR Tambo Coastal Education District. The literature review looked into each of the following aspects of factors influencing enrolment in rural primary schools: challenges resulting in policy issues, the challenge of infrastructure, other factors that influence enrolment in rural school and strategies to overcome enrolment challenges in rural schools. The study was qualitative in nature and employed case study research design. Convenient sampling was used to select four rural primary schools in one Circuit in Port St. Johns Circuit Management Centre (CMC) in OR Tambo Education District. The principal, one (1) educator, one (1) parent and one (1) learner were purposively selected from each school and this made a total of sixteen (16) participants. Face-to-face individual interviews were conducted to gather data about the views and opinions of the participants. Data were analysed using the interpretational analytical strategies. Themes were drawn from the responses of the participants. The major findings were:When the number of learners decreases, the number of educators is also reduced proportionately as a results educators have to take more subjects.There was a negative effect of the relocation of parents, there was poor quality of teaching and learning, the effect of instability crippled normal functioning of the school, there was poor school management as the schools were hit by having no principals due to internal disputes, there were disruptions of teaching and learning due to instability in rural primary schools. The main recommendations are: Rural primary schools should gradually improve the quality of teaching and learning provisioning and arrest the decline in enrolment;At least each class should have an educator, so that discipline can be maintained in all classes; Given the highly technical nature of the process involved in determining the PPN of schools, the DBE, the Provincial Education Departments as well as educator unions should as a matter of priority engage in a massive campaign to capacitate principals on the application of the PPN and its related formula; An audit into the schools' physical infrastructure be conducted to redress the meaningful pedagogical environment of teaching and learning.
- Full Text:
- Authors: Lungu, Simlindile Humphrey
- Date: 2020
- Subjects: Collaboration, school culture, school merger, rationalisation, educator attrition, enrolment, rural, educators, learners.
- Language: English
- Type: Masters , Master of Education (M. Ed)
- Identifier: http://hdl.handle.net/11260/6244 , vital:45343
- Description: The purpose of this study was to investigate the factors influencing enrolment in rural primary schools in one Circuit in Port St. Johns CMC in OR Tambo Coastal Education District. The literature review looked into each of the following aspects of factors influencing enrolment in rural primary schools: challenges resulting in policy issues, the challenge of infrastructure, other factors that influence enrolment in rural school and strategies to overcome enrolment challenges in rural schools. The study was qualitative in nature and employed case study research design. Convenient sampling was used to select four rural primary schools in one Circuit in Port St. Johns Circuit Management Centre (CMC) in OR Tambo Education District. The principal, one (1) educator, one (1) parent and one (1) learner were purposively selected from each school and this made a total of sixteen (16) participants. Face-to-face individual interviews were conducted to gather data about the views and opinions of the participants. Data were analysed using the interpretational analytical strategies. Themes were drawn from the responses of the participants. The major findings were:When the number of learners decreases, the number of educators is also reduced proportionately as a results educators have to take more subjects.There was a negative effect of the relocation of parents, there was poor quality of teaching and learning, the effect of instability crippled normal functioning of the school, there was poor school management as the schools were hit by having no principals due to internal disputes, there were disruptions of teaching and learning due to instability in rural primary schools. The main recommendations are: Rural primary schools should gradually improve the quality of teaching and learning provisioning and arrest the decline in enrolment;At least each class should have an educator, so that discipline can be maintained in all classes; Given the highly technical nature of the process involved in determining the PPN of schools, the DBE, the Provincial Education Departments as well as educator unions should as a matter of priority engage in a massive campaign to capacitate principals on the application of the PPN and its related formula; An audit into the schools' physical infrastructure be conducted to redress the meaningful pedagogical environment of teaching and learning.
- Full Text:
Polymer based electrospun nanofibers as diagnostic probes for the detection of toxic metal ions in water
- Authors: Ondigo, Dezzline Adhiambo
- Date: 2013
- Subjects: Heavy metals , Nanofibers , Nanoparticles , Colorimetric analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4557 , http://hdl.handle.net/10962/d1018261
- Description: The thesis presents the development of polymer based electrospun nanofibers as diagnostic probes for the selective detection of toxic metal ions in water. Through modification of the chemical characteristics of nanofibers by pre- and post-electrospinning treatments, three different diagnostic probes were successfully developed. These were the fluorescent pyridylazo-2-naphthol-poly(acrylic acid) nanofiber probe, the colorimetric probe based on glutathione-stabilized silver/copper alloy nanoparticles and the colorimetric probe based on 2-(2’-Pyridyl)-imidazole functionalized nanofibers. The probes were characterized by Fourier transform infrared spectroscopy (FTIR), Energy dispersive x-ray spectroscopy (EDX), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The fluorescent nanofiber probe was developed towards the determination of Ni²⁺. Covalently functionalized pyridylazo-2-naphthol-poly(acrylic acid) polymeric nanofibers were employed. The solid state Ni²⁺ probe exhibited a good correlation between the fluorescence intensity and nickel concentration up to 1.0 mg/mL based on the Stern-Volmer mechanism. The detection limit of the nanofiber probe was found to be 0.07 ng/mL. The versatility of the fluorescent probe was demonstrated by affording a simple, rapid and selective detection of Ni²⁺ in the presence of other competing metal ions by direct analysis without employing any sample handling steps. For the second part of the study, a simple strategy based on the in-situ synthesis of the glutathione stabilized silver/copper alloy nanoparticles (Ag/Cu alloy NPs) in nylon 6 provided a fast procedure for fabricating a colorimetric probe for the detection of Ni²⁺ in water samples. The electrospun nanofiber composites responded to Ni²⁺ ions but did not suffer any interference from the other metal ions. The effect of Ni²⁺ concentration on the nanocomposite fibers was considered and the “eye-ball” limit of detection was found to be 5.8 μg/mL. Lastly, the third probe was developed by covalently linking an imidazole derivative; 2-(2′-Pyridyl)-imidazole (PIMH) to Poly(vinylbenzyl chloride) (PVBC) and nylon 6 nanofibers by post-electrospinning treatments using a wet chemical method and graft copolymerization technique, respectively. The post-electrospinning modifications of the nanofibers were achieved without altering their fibrous morphology. The color change to red-orange in the presence of Fe²⁺ for both the grafted nylon 6 (white) and the chemically modified PVBC (yellow) nanofibers was instantaneous. The developed diagnostic probes exhibited the desired selectivity towards the targeted metal ions.
- Full Text:
- Date Issued: 2013
- Authors: Ondigo, Dezzline Adhiambo
- Date: 2013
- Subjects: Heavy metals , Nanofibers , Nanoparticles , Colorimetric analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4557 , http://hdl.handle.net/10962/d1018261
- Description: The thesis presents the development of polymer based electrospun nanofibers as diagnostic probes for the selective detection of toxic metal ions in water. Through modification of the chemical characteristics of nanofibers by pre- and post-electrospinning treatments, three different diagnostic probes were successfully developed. These were the fluorescent pyridylazo-2-naphthol-poly(acrylic acid) nanofiber probe, the colorimetric probe based on glutathione-stabilized silver/copper alloy nanoparticles and the colorimetric probe based on 2-(2’-Pyridyl)-imidazole functionalized nanofibers. The probes were characterized by Fourier transform infrared spectroscopy (FTIR), Energy dispersive x-ray spectroscopy (EDX), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The fluorescent nanofiber probe was developed towards the determination of Ni²⁺. Covalently functionalized pyridylazo-2-naphthol-poly(acrylic acid) polymeric nanofibers were employed. The solid state Ni²⁺ probe exhibited a good correlation between the fluorescence intensity and nickel concentration up to 1.0 mg/mL based on the Stern-Volmer mechanism. The detection limit of the nanofiber probe was found to be 0.07 ng/mL. The versatility of the fluorescent probe was demonstrated by affording a simple, rapid and selective detection of Ni²⁺ in the presence of other competing metal ions by direct analysis without employing any sample handling steps. For the second part of the study, a simple strategy based on the in-situ synthesis of the glutathione stabilized silver/copper alloy nanoparticles (Ag/Cu alloy NPs) in nylon 6 provided a fast procedure for fabricating a colorimetric probe for the detection of Ni²⁺ in water samples. The electrospun nanofiber composites responded to Ni²⁺ ions but did not suffer any interference from the other metal ions. The effect of Ni²⁺ concentration on the nanocomposite fibers was considered and the “eye-ball” limit of detection was found to be 5.8 μg/mL. Lastly, the third probe was developed by covalently linking an imidazole derivative; 2-(2′-Pyridyl)-imidazole (PIMH) to Poly(vinylbenzyl chloride) (PVBC) and nylon 6 nanofibers by post-electrospinning treatments using a wet chemical method and graft copolymerization technique, respectively. The post-electrospinning modifications of the nanofibers were achieved without altering their fibrous morphology. The color change to red-orange in the presence of Fe²⁺ for both the grafted nylon 6 (white) and the chemically modified PVBC (yellow) nanofibers was instantaneous. The developed diagnostic probes exhibited the desired selectivity towards the targeted metal ions.
- Full Text:
- Date Issued: 2013
Gold nanoparticle–based colorimetric probes for dopamine detection
- Authors: Ngomane, Nokuthula
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4565 , http://hdl.handle.net/10962/d1021261
- Description: Colorimetric probes have become important tools in analysis and biomedical technology. This thesis reports on the development of such probes for the detection of dopamine (DA). Liquid and different solid state probes were developed utilizing un–functionalized gold nanoparticles (UF–AuNPs). The liquid state probe is based on the growth and aggregation of the UF–AuNPs in the presence of DA. Upon addition of the UF–AuNPs to various concentrations of DA, the shape, size and colour change results in spectral shifts from lower to higher wavelengths. The analyte can be easily monitored by the naked eye from 5.0 nM DA with a calculated limit of detection of 2.5 nM (3σ) under optimal pH. Ascorbic acid (AA) has a potential to interfere with DA detection in solution since it is often present in biological fluids, but in this case the interference was limited to solutions where its concentration was beyond 200 times greater than that of DA. Since most of the previously reported colorimetric probes, especially those for DA are solution based, the main focus of the thesis was in the development of a solid state based colorimetric probe in the form of nanofibre mats. To overcome the interference challenges experienced in the solution studies (the interference by high concentrations of AA), the suitability of molecularly imprinted polymers (MIPs) for the selective detection of DA was investigated. The results showed that the MIPs produced did not play a significant role in enhancing the selectivity towards DA. A probe composed of just the UF–AuNPs and Nylon–6 (UF–AuNPs + N6) was also developed. The UF–AuNPs were synthesized following an in situ reduction method. The probe was only selective to DA and insensitive to other catecholamines at physiological pH. Thus, the probe did not require any addition functionalities to achieve selectivity and sensitive to DA. The liquid state probe and the composite UF–AuNPs + N6 nanofibre probe were successfully applied to a whole blood sample and showed good selectivity towards DA. The simple, sensitive and selective probe could be an excellent alternative for on–site and immediate detection of DA without the use of instrumentation. For quantification of DA using the solid state probe, open–source software imageJ was used to assist in the analysis of the nanofibre colours. It was observed that the intensity of the colour increased with the increase in concentration of DA in a linear fashion. The use of imageJ can also be a great alternative where the colour changes are not so clear or for visually impaired people. The solid state probe developed can detect DA qualitatively and quantitatively. The work also forms a good foundation for development of such probes for other analyte.
- Full Text:
- Date Issued: 2016
- Authors: Ngomane, Nokuthula
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4565 , http://hdl.handle.net/10962/d1021261
- Description: Colorimetric probes have become important tools in analysis and biomedical technology. This thesis reports on the development of such probes for the detection of dopamine (DA). Liquid and different solid state probes were developed utilizing un–functionalized gold nanoparticles (UF–AuNPs). The liquid state probe is based on the growth and aggregation of the UF–AuNPs in the presence of DA. Upon addition of the UF–AuNPs to various concentrations of DA, the shape, size and colour change results in spectral shifts from lower to higher wavelengths. The analyte can be easily monitored by the naked eye from 5.0 nM DA with a calculated limit of detection of 2.5 nM (3σ) under optimal pH. Ascorbic acid (AA) has a potential to interfere with DA detection in solution since it is often present in biological fluids, but in this case the interference was limited to solutions where its concentration was beyond 200 times greater than that of DA. Since most of the previously reported colorimetric probes, especially those for DA are solution based, the main focus of the thesis was in the development of a solid state based colorimetric probe in the form of nanofibre mats. To overcome the interference challenges experienced in the solution studies (the interference by high concentrations of AA), the suitability of molecularly imprinted polymers (MIPs) for the selective detection of DA was investigated. The results showed that the MIPs produced did not play a significant role in enhancing the selectivity towards DA. A probe composed of just the UF–AuNPs and Nylon–6 (UF–AuNPs + N6) was also developed. The UF–AuNPs were synthesized following an in situ reduction method. The probe was only selective to DA and insensitive to other catecholamines at physiological pH. Thus, the probe did not require any addition functionalities to achieve selectivity and sensitive to DA. The liquid state probe and the composite UF–AuNPs + N6 nanofibre probe were successfully applied to a whole blood sample and showed good selectivity towards DA. The simple, sensitive and selective probe could be an excellent alternative for on–site and immediate detection of DA without the use of instrumentation. For quantification of DA using the solid state probe, open–source software imageJ was used to assist in the analysis of the nanofibre colours. It was observed that the intensity of the colour increased with the increase in concentration of DA in a linear fashion. The use of imageJ can also be a great alternative where the colour changes are not so clear or for visually impaired people. The solid state probe developed can detect DA qualitatively and quantitatively. The work also forms a good foundation for development of such probes for other analyte.
- Full Text:
- Date Issued: 2016
A study of a class of invariant optimal control problems on the Euclidean group SE(2)
- Authors: Adams, Ross Montague
- Date: 2011
- Subjects: Matrix groups Lie groups Extremal problems (Mathematics) Maximum principles (Mathematics) Hamilton-Jacobi equations Lyapunov stability
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5420 , http://hdl.handle.net/10962/d1006060
- Description: The aim of this thesis is to study a class of left-invariant optimal control problems on the matrix Lie group SE(2). We classify, under detached feedback equivalence, all controllable (left-invariant) control affine systems on SE(2). This result produces six types of control affine systems on SE(2). Hence, we study six associated left-invariant optimal control problems on SE(2). A left-invariant optimal control problem consists of minimizing a cost functional over the trajectory-control pairs of a left-invariant control system subject to appropriate boundary conditions. Each control problem is lifted from SE(2) to T*SE(2) ≅ SE(2) x se (2)*and then reduced to a problem on se (2)*. The maximum principle is used to obtain the optimal control and Hamiltonian corresponding to the normal extremals. Then we derive the (reduced) extremal equations on se (2)*. These equations are explicitly integrated by trigonometric and Jacobi elliptic functions. Finally, we fully classify, under Lyapunov stability, the equilibrium states of the normal extremal equations for each of the six types under consideration.
- Full Text:
- Date Issued: 2011
- Authors: Adams, Ross Montague
- Date: 2011
- Subjects: Matrix groups Lie groups Extremal problems (Mathematics) Maximum principles (Mathematics) Hamilton-Jacobi equations Lyapunov stability
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5420 , http://hdl.handle.net/10962/d1006060
- Description: The aim of this thesis is to study a class of left-invariant optimal control problems on the matrix Lie group SE(2). We classify, under detached feedback equivalence, all controllable (left-invariant) control affine systems on SE(2). This result produces six types of control affine systems on SE(2). Hence, we study six associated left-invariant optimal control problems on SE(2). A left-invariant optimal control problem consists of minimizing a cost functional over the trajectory-control pairs of a left-invariant control system subject to appropriate boundary conditions. Each control problem is lifted from SE(2) to T*SE(2) ≅ SE(2) x se (2)*and then reduced to a problem on se (2)*. The maximum principle is used to obtain the optimal control and Hamiltonian corresponding to the normal extremals. Then we derive the (reduced) extremal equations on se (2)*. These equations are explicitly integrated by trigonometric and Jacobi elliptic functions. Finally, we fully classify, under Lyapunov stability, the equilibrium states of the normal extremal equations for each of the six types under consideration.
- Full Text:
- Date Issued: 2011
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
The acoustic niche and conservation status of the recently described Hogsback caco, Cacosternum thorini (Amphibia: Pyxicephalidae), Hogsback, Eastern Cape, South Africa
- Authors: Kom, Nokuthula
- Date: 2021-02
- Subjects: Amphibians
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20429 , vital:45665
- Description: Animals may compete for acoustic space (acoustic niche) in the same way they do for habitat space. The most intense competition involves individuals with the most similar resource requirements (i.e. conspecifics), but if competition is interspecific, then mate recognition must occur both within and between species. The coexistence of the bronze caco (Cacosternum nanum) and the Hogsback caco (C. thorini) in the Tor Doone area of Hogsback could be interpreted as a result of past competition, which drove acoustic partitioning by means of the evolution of specific calls that do not overlap in frequency. Frogs are known to coexist well with other frog species because of their highly specific advertisement calls, which differ even between closely related species. One of the main aims of the project was to record and provide a description of the call of the recently described Hogsback caco, C. thorini. I identified 30 calling males and recorded each for 10 min in February 2016, yielding a total of 235 calls. Summary values for the calls include duration of 40 ± 14 ms, with 16 ± 5 pulses produced at a pulse-rate of 46 ± 21 s-1 and a mean dominant frequency of 4.19 ± 0.58 kHz. The call of C. thorini differs from those of all other cacos, by its incremental structure (increased number of pulses within consecutive units). My second goal was to use playbacks to investigate the preferred habitat of C. thorini and to compare it with that of C. nanum. I conducted experiments to measure the propagation of C. thorini and C. nanum calls in three different habitats (C. thorini habitat, C. nanum habitat, and grassland with no water bodies). Finally, I investigated the effect of drought and flood on the pools used by males as calling sites, using a buried basin to which I added water in 10 litre aliquots. The optimal water level for call propagation in the artificial pools was half-full. Using playbacks, I tested whether the two species responded to each other’s calls. I found that, although the two species call at the same time and each call in response to the other’s calls, they do not recognise heterospecific calls; they simply respond to noise. I found no evidence of acoustic competition between the two species, and in fact, the abundant, dominant species, C. nanum, was rare in the C. thorini preferred habitat. The results of this study may assist efforts to conserve endemic amphibians in the Amatola Mountains. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-02
- Authors: Kom, Nokuthula
- Date: 2021-02
- Subjects: Amphibians
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20429 , vital:45665
- Description: Animals may compete for acoustic space (acoustic niche) in the same way they do for habitat space. The most intense competition involves individuals with the most similar resource requirements (i.e. conspecifics), but if competition is interspecific, then mate recognition must occur both within and between species. The coexistence of the bronze caco (Cacosternum nanum) and the Hogsback caco (C. thorini) in the Tor Doone area of Hogsback could be interpreted as a result of past competition, which drove acoustic partitioning by means of the evolution of specific calls that do not overlap in frequency. Frogs are known to coexist well with other frog species because of their highly specific advertisement calls, which differ even between closely related species. One of the main aims of the project was to record and provide a description of the call of the recently described Hogsback caco, C. thorini. I identified 30 calling males and recorded each for 10 min in February 2016, yielding a total of 235 calls. Summary values for the calls include duration of 40 ± 14 ms, with 16 ± 5 pulses produced at a pulse-rate of 46 ± 21 s-1 and a mean dominant frequency of 4.19 ± 0.58 kHz. The call of C. thorini differs from those of all other cacos, by its incremental structure (increased number of pulses within consecutive units). My second goal was to use playbacks to investigate the preferred habitat of C. thorini and to compare it with that of C. nanum. I conducted experiments to measure the propagation of C. thorini and C. nanum calls in three different habitats (C. thorini habitat, C. nanum habitat, and grassland with no water bodies). Finally, I investigated the effect of drought and flood on the pools used by males as calling sites, using a buried basin to which I added water in 10 litre aliquots. The optimal water level for call propagation in the artificial pools was half-full. Using playbacks, I tested whether the two species responded to each other’s calls. I found that, although the two species call at the same time and each call in response to the other’s calls, they do not recognise heterospecific calls; they simply respond to noise. I found no evidence of acoustic competition between the two species, and in fact, the abundant, dominant species, C. nanum, was rare in the C. thorini preferred habitat. The results of this study may assist efforts to conserve endemic amphibians in the Amatola Mountains. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-02
An assessment of the performance appraisal system utilised for junior and middle level management within the South African National Defence Force
- Authors: Terblanche, Graham Martin
- Date: 2004
- Subjects: Middle managers -- Rating of -- South Africa , South Africa. National Defence Force Officials and employees Rating of
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10884 , http://hdl.handle.net/10948/148 , Middle managers -- Rating of -- South Africa , South Africa. National Defence Force Officials and employees Rating of
- Description: The research problem of this study was to assess the extent to which the appraisal system for junior and middle level managers in the South African National Defence Force (SANDF) met the requirements and guidelines for performance appraisal as stipulated in the literature. To achieve this objective, the following procedure was followed: · A survey of existing literature, related to performance appraisal, was conducted. The literature study focused on the requirements for an effective performance appraisal system, appraisal methods and appraisal errors. Attention was also focused on who should take responsibility for performance appraisal and the importance of regularly evaluating the performance appraisal system to meet the demands of a changing environment. The second part of the literature study dealt with the guidelines for establishing an effective appraisal system as well as performance management processes and cycles that are critical for the effectiveness of an appraisal system. The theoretical study formed the basis for the development of a survey questionnaire to establish the extent to which junior and middle level managers in the SANDF agreed with the theoretical guidelines. The survey was administered to a randomly selected group of junior and middle level managers who were representative of the South African Army, Airforce and Medical Services. The empirical results indicated that there was concurrence with many of the guidelines in the literature, but that there were areas that could be improved. It became evident that many respondents felt that the current system was not entirely fair and was not adapted to meet the needs of the integrated SANDF. Specifically, results indicated that the system should be re-evaluated to eliminate bias and to enhance the development of clear standards, both on a quantitative and qualitative level. It became clear that training and communication were important to the successful development and utilisation of a performance appraisal system. An effective performance appraisal system that is integrated with the overall performance management system of an organisation will enhance productivity, satisfaction and the attainment of goals.
- Full Text:
- Date Issued: 2004
- Authors: Terblanche, Graham Martin
- Date: 2004
- Subjects: Middle managers -- Rating of -- South Africa , South Africa. National Defence Force Officials and employees Rating of
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10884 , http://hdl.handle.net/10948/148 , Middle managers -- Rating of -- South Africa , South Africa. National Defence Force Officials and employees Rating of
- Description: The research problem of this study was to assess the extent to which the appraisal system for junior and middle level managers in the South African National Defence Force (SANDF) met the requirements and guidelines for performance appraisal as stipulated in the literature. To achieve this objective, the following procedure was followed: · A survey of existing literature, related to performance appraisal, was conducted. The literature study focused on the requirements for an effective performance appraisal system, appraisal methods and appraisal errors. Attention was also focused on who should take responsibility for performance appraisal and the importance of regularly evaluating the performance appraisal system to meet the demands of a changing environment. The second part of the literature study dealt with the guidelines for establishing an effective appraisal system as well as performance management processes and cycles that are critical for the effectiveness of an appraisal system. The theoretical study formed the basis for the development of a survey questionnaire to establish the extent to which junior and middle level managers in the SANDF agreed with the theoretical guidelines. The survey was administered to a randomly selected group of junior and middle level managers who were representative of the South African Army, Airforce and Medical Services. The empirical results indicated that there was concurrence with many of the guidelines in the literature, but that there were areas that could be improved. It became evident that many respondents felt that the current system was not entirely fair and was not adapted to meet the needs of the integrated SANDF. Specifically, results indicated that the system should be re-evaluated to eliminate bias and to enhance the development of clear standards, both on a quantitative and qualitative level. It became clear that training and communication were important to the successful development and utilisation of a performance appraisal system. An effective performance appraisal system that is integrated with the overall performance management system of an organisation will enhance productivity, satisfaction and the attainment of goals.
- Full Text:
- Date Issued: 2004
Antimalarial secondary metabolites from Morinda lucida
- Authors: Chithambo, Bertha
- Date: 2017
- Subjects: Botanical chemistry , Anthraquinones , Antimalarials , Rubiaceae -- Therapeutic use , Malaria -- Treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/45730 , vital:25535
- Description: Antimalarial activities of secondary metabolites from Morinda lucida (Rubiaceae), were investigated. Even though M. lucida is traditionally used to treat malaria, diabetes, jaundice, hypertension, dysentery and many other diseases, the compounds in this plant have not yet been fully investigated and characterised. Most of the studies that have been done on this plant focused on the medicinal properties of the crude extracts but have not gone further to isolate and characterise the compounds. In this study, the methanol - dichloromethane crude extract from the bark of M. lucida was fractionated into fractions 1-8. Fractions 2-5 were purified in order to isolate active secondary metabolites. The isolated pure compounds were characterised and identified. An in vitro antimalarial assay was carried out on the crude extract, fractions, pure compounds and solutions made from different combinations of pure compounds using the parasite lactate dehydrogenase (pLDH) assay. An IC50 done on the methanolic crude extract gave a value of 25 µg/mL. The % cell viability for the crude extract in cell toxicity assay remained at 100%. Each of the pure compounds tested had very little activity. Their activities were increased when samples from the different compounds were mixed. One of these mixtures reduced malaria viability to about 22 % at 20 µM and gave an IC50 value of 17 µM. Antibacterial assays were also carried out on the crude extract and fractions. Fractions 2 and 3 were relatively active (MIC values ranging between 125-1000 µg/mL) against M. cattarhalis and E. faecalis. Fraction 2 was also the most active on S. typhimurium and S. aureus (MIC value of 1000 µg/mL) compared with the other fractions. This same fraction also showed some activity against M. tuberculosis with MIC90 and MIC99 values of 40.9 and 46.3 µg/mL respectively in an anti-tuberculosis assay.The following compounds, comprising of iridoids (asperuloside and asperulosidic acid), terpenoids (stigmasterol, P-sitosterol, campesterol, lanosterol and cycloartenol) and anthraquinones [5,15-O-dimethylmorindol, 1,7-dihydroxy-2-methoxy-5-(methoxymethyl) anthraquinone and 1,6-dihydroxy-2-methoxy-5-(methoxymethyl)anthraquinone], were isolated. All these compounds have been isolated from different plants before with the exception of 1,7-dihydroxy-2-methoxy-5-(methoxymethyl)anthraquinone and 1,6-dihydroxy-2-methoxy-5-(methoxymethyl)anthraquinone which were tentatively assigned the structures due to insufficient data. To the best of our knowledge, this is the first report on the identification of all of the mentioned compounds, with the exception of ß-sitosterol and stigmasterol, from M. lucida. Molecular docking was performed on one of the isolated anthraquinones (5,15-O- dimethylmorindol) to check if it can bind to cytochrome bci, a known target for atovaquone. This compound interacted with the same amino acids that atovaquone, a well known antimalarial agent, interacted with on cytochrome bc1 indicating a possible similar mode of action.
- Full Text:
- Date Issued: 2017
- Authors: Chithambo, Bertha
- Date: 2017
- Subjects: Botanical chemistry , Anthraquinones , Antimalarials , Rubiaceae -- Therapeutic use , Malaria -- Treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/45730 , vital:25535
- Description: Antimalarial activities of secondary metabolites from Morinda lucida (Rubiaceae), were investigated. Even though M. lucida is traditionally used to treat malaria, diabetes, jaundice, hypertension, dysentery and many other diseases, the compounds in this plant have not yet been fully investigated and characterised. Most of the studies that have been done on this plant focused on the medicinal properties of the crude extracts but have not gone further to isolate and characterise the compounds. In this study, the methanol - dichloromethane crude extract from the bark of M. lucida was fractionated into fractions 1-8. Fractions 2-5 were purified in order to isolate active secondary metabolites. The isolated pure compounds were characterised and identified. An in vitro antimalarial assay was carried out on the crude extract, fractions, pure compounds and solutions made from different combinations of pure compounds using the parasite lactate dehydrogenase (pLDH) assay. An IC50 done on the methanolic crude extract gave a value of 25 µg/mL. The % cell viability for the crude extract in cell toxicity assay remained at 100%. Each of the pure compounds tested had very little activity. Their activities were increased when samples from the different compounds were mixed. One of these mixtures reduced malaria viability to about 22 % at 20 µM and gave an IC50 value of 17 µM. Antibacterial assays were also carried out on the crude extract and fractions. Fractions 2 and 3 were relatively active (MIC values ranging between 125-1000 µg/mL) against M. cattarhalis and E. faecalis. Fraction 2 was also the most active on S. typhimurium and S. aureus (MIC value of 1000 µg/mL) compared with the other fractions. This same fraction also showed some activity against M. tuberculosis with MIC90 and MIC99 values of 40.9 and 46.3 µg/mL respectively in an anti-tuberculosis assay.The following compounds, comprising of iridoids (asperuloside and asperulosidic acid), terpenoids (stigmasterol, P-sitosterol, campesterol, lanosterol and cycloartenol) and anthraquinones [5,15-O-dimethylmorindol, 1,7-dihydroxy-2-methoxy-5-(methoxymethyl) anthraquinone and 1,6-dihydroxy-2-methoxy-5-(methoxymethyl)anthraquinone], were isolated. All these compounds have been isolated from different plants before with the exception of 1,7-dihydroxy-2-methoxy-5-(methoxymethyl)anthraquinone and 1,6-dihydroxy-2-methoxy-5-(methoxymethyl)anthraquinone which were tentatively assigned the structures due to insufficient data. To the best of our knowledge, this is the first report on the identification of all of the mentioned compounds, with the exception of ß-sitosterol and stigmasterol, from M. lucida. Molecular docking was performed on one of the isolated anthraquinones (5,15-O- dimethylmorindol) to check if it can bind to cytochrome bci, a known target for atovaquone. This compound interacted with the same amino acids that atovaquone, a well known antimalarial agent, interacted with on cytochrome bc1 indicating a possible similar mode of action.
- Full Text:
- Date Issued: 2017
Fungal remediation of winery and distillery wastewaters using Trametes pubescens MB 89 and the enhanced production of a high-value enzyme therein
- Authors: Strong, Peter James
- Date: 2008
- Subjects: Fungal remediation Distilleries -- Waste disposal Wine and wine making -- Waste disposal Bioremediation Laccase Enzymes -- Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3932 , http://hdl.handle.net/10962/d1003991
- Description: In this study white-rot fungi were investigated for their efficiency at distillery wastewater remediation and the production of laccase as a valuable by-product. Distillery wastewaters are high in organic load and low in pH. The presence of phenolic compounds can lead to extremely colour-rich wastewaters and can be toxic to microorganisms. The presence of the inorganic ions may also affect biological treatment. White-rot fungi are unique among eukaryotic or prokaryotic microbes in possessing powerful oxidative enzyme systems that can degrade lignin to carbon dioxide. These ligninolytic enzymes, such as lignin peroxidase, manganese peroxidase and laccase, are capable of degrading a vast range of toxic, recalcitrant environmental pollutants and this makes the white-rot fungi strong candidates for the bioremediation of polluted soils and waters. The laccase enzyme alone has shown remediation potential in wastewaters such as beer production effluent, olive mill wastewater, alcohol distillery wastes, dye-containing wastewaters from the textile industry as well as wastewaters from the paper and pulp industry. It has been shown to be capable of remediating soils and waters polluted with chlorinated phenolic compounds, polyaromatic hydrocarbons, nitrosubstituted compounds and fungicides, herbicides and insecticides.
- Full Text:
- Date Issued: 2008
- Authors: Strong, Peter James
- Date: 2008
- Subjects: Fungal remediation Distilleries -- Waste disposal Wine and wine making -- Waste disposal Bioremediation Laccase Enzymes -- Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3932 , http://hdl.handle.net/10962/d1003991
- Description: In this study white-rot fungi were investigated for their efficiency at distillery wastewater remediation and the production of laccase as a valuable by-product. Distillery wastewaters are high in organic load and low in pH. The presence of phenolic compounds can lead to extremely colour-rich wastewaters and can be toxic to microorganisms. The presence of the inorganic ions may also affect biological treatment. White-rot fungi are unique among eukaryotic or prokaryotic microbes in possessing powerful oxidative enzyme systems that can degrade lignin to carbon dioxide. These ligninolytic enzymes, such as lignin peroxidase, manganese peroxidase and laccase, are capable of degrading a vast range of toxic, recalcitrant environmental pollutants and this makes the white-rot fungi strong candidates for the bioremediation of polluted soils and waters. The laccase enzyme alone has shown remediation potential in wastewaters such as beer production effluent, olive mill wastewater, alcohol distillery wastes, dye-containing wastewaters from the textile industry as well as wastewaters from the paper and pulp industry. It has been shown to be capable of remediating soils and waters polluted with chlorinated phenolic compounds, polyaromatic hydrocarbons, nitrosubstituted compounds and fungicides, herbicides and insecticides.
- Full Text:
- Date Issued: 2008
Reactivity of Rhenium (iii) and Rhenium (V) with multidentate NN-and no-donor ligands
- Yumata, Nonzaliseko Christine
- Authors: Yumata, Nonzaliseko Christine
- Date: 2010
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10373 , http://hdl.handle.net/10948/1085 , Rhenium , Ligands
- Description: The reaction of the potentially tridentate Schiff-base chelate Hhaep [Haep = N’-(1- (2-hydroxyphenyl)ethylidene)benzohydrazide] with [ReCl3(benzil)(PPh3)] and trans-[ReOCl3(PPh3)2] produced the neutral oxorhenium(V) complexes cis- [ReOCl2(mep)] [Hmep = 2-(1-iminoethyl)phenol] and cis-[ReOCI2(meb)(PPh3)] [Hmeb = N’-(propan-2-ylidene)benzohydrazide] in ethanol and acetone respectively. In both reactions the Hhaep molecule cleaves to give different coordinated bidentate NO-donor chelates coordinated to the rhenium(V) centers. The X-ray studies reveal that mep is present as a bidentate, monoanionic Schiffbase coordinating through the neutral imino nitrogen and the deprotonated phenolate oxygen in cis-[ReOCl2(mep)]. The bond distances and angles in cis- [ReOCI2(meb)(PPh3)] confirm that meb coordinates to the metal in the enolate form. The distorted octahedral complex fac-[ReCl3(dpa)(PPh3)] was prepared by the reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of dpa in acetonitrile under a nitrogen atmosphere. The compound dpa.HCl.2H2O was obtained as a by-product in the reaction of dpa with trans-[ReCI3(MeCN)(PPh3)2] in acetonitrile. The reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of 6- amino-3-methyl-1-phenyl-4-azahept-2-ene-1-one (Hamp) in acetonitrile led to the isolation of cis-[ReCl2(bat)(PPh3)2]. On complexation to the metal center Hamp decomposed to give the coordinated benzoylacetone (bat). Bat is present as a monoanionic bidentate chelate. The complexes [ReVOCI(had)] and [ReIVCl(had)(PPh3)](ReO4) were prepared from the reaction of trans-[ReCl3(MeCN)(PPh3)2] with N,N-bis((2-hydroxybenzyl)-2- aminoethyl)dimethylamine (H2had) in ethanol under various reaction conditions. The treatment of [ReCl3(benzil)(PPh3)] with 2-[((2- pyridinylmethyl)amino)methyl]phenol (Hham) in a 2:1 molar ratio in acetonitrile led to the isolation of the hydrogen-bonded dimer [ReOCl2(ham)]2. The distorted octahedral complex [ReOCl(hap)] [H2hap = N,N-bis(2- hydroxybenzyl)aminomethylpyridine] was prepared from the reaction of trans- [ReCl3(MeCN)(PPh3)2] with a twofold molar excess of H2hap in acetonitrile. The X-ray crystal structure analysis shows that the chloride is coordinated trans to the tripodal tertiary amino nitrogen, with a phenolate oxygen trans to the oxo oxygen.
- Full Text:
- Date Issued: 2010
- Authors: Yumata, Nonzaliseko Christine
- Date: 2010
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10373 , http://hdl.handle.net/10948/1085 , Rhenium , Ligands
- Description: The reaction of the potentially tridentate Schiff-base chelate Hhaep [Haep = N’-(1- (2-hydroxyphenyl)ethylidene)benzohydrazide] with [ReCl3(benzil)(PPh3)] and trans-[ReOCl3(PPh3)2] produced the neutral oxorhenium(V) complexes cis- [ReOCl2(mep)] [Hmep = 2-(1-iminoethyl)phenol] and cis-[ReOCI2(meb)(PPh3)] [Hmeb = N’-(propan-2-ylidene)benzohydrazide] in ethanol and acetone respectively. In both reactions the Hhaep molecule cleaves to give different coordinated bidentate NO-donor chelates coordinated to the rhenium(V) centers. The X-ray studies reveal that mep is present as a bidentate, monoanionic Schiffbase coordinating through the neutral imino nitrogen and the deprotonated phenolate oxygen in cis-[ReOCl2(mep)]. The bond distances and angles in cis- [ReOCI2(meb)(PPh3)] confirm that meb coordinates to the metal in the enolate form. The distorted octahedral complex fac-[ReCl3(dpa)(PPh3)] was prepared by the reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of dpa in acetonitrile under a nitrogen atmosphere. The compound dpa.HCl.2H2O was obtained as a by-product in the reaction of dpa with trans-[ReCI3(MeCN)(PPh3)2] in acetonitrile. The reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of 6- amino-3-methyl-1-phenyl-4-azahept-2-ene-1-one (Hamp) in acetonitrile led to the isolation of cis-[ReCl2(bat)(PPh3)2]. On complexation to the metal center Hamp decomposed to give the coordinated benzoylacetone (bat). Bat is present as a monoanionic bidentate chelate. The complexes [ReVOCI(had)] and [ReIVCl(had)(PPh3)](ReO4) were prepared from the reaction of trans-[ReCl3(MeCN)(PPh3)2] with N,N-bis((2-hydroxybenzyl)-2- aminoethyl)dimethylamine (H2had) in ethanol under various reaction conditions. The treatment of [ReCl3(benzil)(PPh3)] with 2-[((2- pyridinylmethyl)amino)methyl]phenol (Hham) in a 2:1 molar ratio in acetonitrile led to the isolation of the hydrogen-bonded dimer [ReOCl2(ham)]2. The distorted octahedral complex [ReOCl(hap)] [H2hap = N,N-bis(2- hydroxybenzyl)aminomethylpyridine] was prepared from the reaction of trans- [ReCl3(MeCN)(PPh3)2] with a twofold molar excess of H2hap in acetonitrile. The X-ray crystal structure analysis shows that the chloride is coordinated trans to the tripodal tertiary amino nitrogen, with a phenolate oxygen trans to the oxo oxygen.
- Full Text:
- Date Issued: 2010