Synthesis of zinc phthalocyanine derivatives for possible use in photodynamic therapy
- Authors: Matlaba, Pulane Maseleka
- Date: 2003
- Subjects: Photochemotherapy , Electrochemistry , Phthalocyanines , Zinc
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4374 , http://hdl.handle.net/10962/d1005039 , Photochemotherapy , Electrochemistry , Phthalocyanines , Zinc
- Description: The synthesis of symmetrically and unsymmetrically substituted zinc phthalocyanines (ZnPc) derivatives is done according to reported procedures. The unsymmetrical ZnPc derivatives are synthesized by ring expansion of sub-phthalocyanine complexes. Ring substitution is effected with tert-butyl phenol, naphthol, and hydroxybenzoic acid. Comparison of the redox potentials for the complexes substituted with varying numbers of tert-butyl phenol: 1, 2, 3, 6 and 8 show that the complex with the highest number of substituents are more difficult to oxidize and easier to reduce. Water soluble sulphonated ZnPc (ZnPcSn) was prepared. The possibility of using axial ligation to increase the solubility and the photochemical activity of sulphotnated ZnPc in aqueous solutions was investigated. Pyridine, aminopyridyl and bipyridyl were used as axial ligands. When bipyridyl was used as the axial ligand, solubility of the ZnPcSn increased, shown by the increase in the Q-band of the monomer species in solution and the singlet oxygen quantum yields was relatively higher than that of the unligated ZnPcSn. The singlet oxygen quantum yields by the various complexes in DMF using diphenylisobenzofuran as a chemical quencher for organic solvent were determined. Singlet oxygen quantum yields for the unsymmetrically ring substituted complexes range from 0.22 to 0.68. Photobleaching quantum yields are in the order of 10-5, which means that the complexes are relatively photostable.
- Full Text:
- Authors: Matlaba, Pulane Maseleka
- Date: 2003
- Subjects: Photochemotherapy , Electrochemistry , Phthalocyanines , Zinc
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4374 , http://hdl.handle.net/10962/d1005039 , Photochemotherapy , Electrochemistry , Phthalocyanines , Zinc
- Description: The synthesis of symmetrically and unsymmetrically substituted zinc phthalocyanines (ZnPc) derivatives is done according to reported procedures. The unsymmetrical ZnPc derivatives are synthesized by ring expansion of sub-phthalocyanine complexes. Ring substitution is effected with tert-butyl phenol, naphthol, and hydroxybenzoic acid. Comparison of the redox potentials for the complexes substituted with varying numbers of tert-butyl phenol: 1, 2, 3, 6 and 8 show that the complex with the highest number of substituents are more difficult to oxidize and easier to reduce. Water soluble sulphonated ZnPc (ZnPcSn) was prepared. The possibility of using axial ligation to increase the solubility and the photochemical activity of sulphotnated ZnPc in aqueous solutions was investigated. Pyridine, aminopyridyl and bipyridyl were used as axial ligands. When bipyridyl was used as the axial ligand, solubility of the ZnPcSn increased, shown by the increase in the Q-band of the monomer species in solution and the singlet oxygen quantum yields was relatively higher than that of the unligated ZnPcSn. The singlet oxygen quantum yields by the various complexes in DMF using diphenylisobenzofuran as a chemical quencher for organic solvent were determined. Singlet oxygen quantum yields for the unsymmetrically ring substituted complexes range from 0.22 to 0.68. Photobleaching quantum yields are in the order of 10-5, which means that the complexes are relatively photostable.
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Synthesis, spectral and electrochemical properties of a new family of pyrrole substituted cobalt, iron, manganese, nickel and zinc phthalocyanine complexes
- Obirai, Joe, Rodrigues, Nazaré Pereira, Bedioui, Fethi, Nyokong, Tebello
- Authors: Obirai, Joe , Rodrigues, Nazaré Pereira , Bedioui, Fethi , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304852 , vital:58496 , xlink:href="https://0-doi.org.wam.seals.ac.za/10.1142/S1088424603000641"
- Description: A new family of pyrrole substituted metallophthalocyanine complexes, namely cobalt(II), iron(II), manganese(III), nickel(II) and zinc(II) tetrakis-4-(pyrrol-1-yl)phenoxy phthalocyanines (noted as M(TPhPyrPc), where M is the metallic cation) have been synthesized and fully characterized. In particular, the UV-visible spectra of the iron and nickel complexes showed extensive aggregation even at low concentrations. The cyclic voltammetry of the cobalt, iron and manganese complexes showed three to four redox couples assigned to metal and ring based processes. Spectroelectrochemistry of the manganese derivative confirmed that the synthesized complex is MnIII(TPhPyrPc-2) and that the reduction of MnII(TPhPyrPc-2) to be centred on the ring and rather than on the metal, forming the MnII(TPhPyrPc-4) species. Also, the electrochemical polymerization of these newly synthesized pyrrole-substituted phthalocyanines has been demonstrated in the case of the cobalt complex and the electrocatalytic activity of the obtained film has been tested towards the oxidation of L-cysteine.
- Full Text:
- Authors: Obirai, Joe , Rodrigues, Nazaré Pereira , Bedioui, Fethi , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304852 , vital:58496 , xlink:href="https://0-doi.org.wam.seals.ac.za/10.1142/S1088424603000641"
- Description: A new family of pyrrole substituted metallophthalocyanine complexes, namely cobalt(II), iron(II), manganese(III), nickel(II) and zinc(II) tetrakis-4-(pyrrol-1-yl)phenoxy phthalocyanines (noted as M(TPhPyrPc), where M is the metallic cation) have been synthesized and fully characterized. In particular, the UV-visible spectra of the iron and nickel complexes showed extensive aggregation even at low concentrations. The cyclic voltammetry of the cobalt, iron and manganese complexes showed three to four redox couples assigned to metal and ring based processes. Spectroelectrochemistry of the manganese derivative confirmed that the synthesized complex is MnIII(TPhPyrPc-2) and that the reduction of MnII(TPhPyrPc-2) to be centred on the ring and rather than on the metal, forming the MnII(TPhPyrPc-4) species. Also, the electrochemical polymerization of these newly synthesized pyrrole-substituted phthalocyanines has been demonstrated in the case of the cobalt complex and the electrocatalytic activity of the obtained film has been tested towards the oxidation of L-cysteine.
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Synthesis, spectroscopy and photochemistry of octasubstituted thiol-derivatized phthalocyaninatozinc (II) complexes
- Ozoemena, Kenneth I, Nyokong, Tebello
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290401 , vital:56746 , xlink:href="https://doi.org/10.1016/S1387-7003(03)00218-1"
- Description: Synthesis, spectroscopic and photochemical characterization of phenylthiol-derivatized zinc phthalocyanine complex: 2,3,9,10,16,17,23,24-octa(4-methylphenylthio-)phthalocyaninatozinc(II) [ZnPc(SC6H4CH3)8] (3a) and its alkanethiol derivative, 2,3,9,10,16,17,23,24-octabutylthiophthalocyaninatozinc(II) [ZnPc(SC4H9)8] (3b) are described. Spectroscopic analyses show that 3a has a higher aggregation tendency than 3b in organic solvents. Photochemical studies indicate that 3b is more photostable and more efficient at singlet oxygen generation than 3a.
- Full Text:
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290401 , vital:56746 , xlink:href="https://doi.org/10.1016/S1387-7003(03)00218-1"
- Description: Synthesis, spectroscopic and photochemical characterization of phenylthiol-derivatized zinc phthalocyanine complex: 2,3,9,10,16,17,23,24-octa(4-methylphenylthio-)phthalocyaninatozinc(II) [ZnPc(SC6H4CH3)8] (3a) and its alkanethiol derivative, 2,3,9,10,16,17,23,24-octabutylthiophthalocyaninatozinc(II) [ZnPc(SC4H9)8] (3b) are described. Spectroscopic analyses show that 3a has a higher aggregation tendency than 3b in organic solvents. Photochemical studies indicate that 3b is more photostable and more efficient at singlet oxygen generation than 3a.
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Teenage pregnancy and the construction of adolescence : scientific literature in South Africa
- Authors: Macleod, Catriona I
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6258 , http://hdl.handle.net/10962/d1007876 , http://journals.sagepub.com/doi/10.1177/0907568203104003
- Description: The depiction of teenage pregnancy as a social problem relies on the assumption of adolescence as a separable stage of development. Utilising a Derridian framework, I analyse how the dominant construction of adolescence as a transitional stage: (1) acts as an attempt to decide the undecidable (viz. the adolescent who is neither child nor adult, but simultaneously both) – an attempt which collapses in the face of teenage pregnancy; (2) relies on the ideal adult as the endpoint of development, and (3) has effects in terms of gendered and expert/parent/adolescent power relations.
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- Authors: Macleod, Catriona I
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6258 , http://hdl.handle.net/10962/d1007876 , http://journals.sagepub.com/doi/10.1177/0907568203104003
- Description: The depiction of teenage pregnancy as a social problem relies on the assumption of adolescence as a separable stage of development. Utilising a Derridian framework, I analyse how the dominant construction of adolescence as a transitional stage: (1) acts as an attempt to decide the undecidable (viz. the adolescent who is neither child nor adult, but simultaneously both) – an attempt which collapses in the face of teenage pregnancy; (2) relies on the ideal adult as the endpoint of development, and (3) has effects in terms of gendered and expert/parent/adolescent power relations.
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The anorexic mask : a case study of a patient with co-morbid nervosa and factitious disorder?
- Authors: Gaylard, Jeanne
- Date: 2003
- Subjects: Anorexia nervosa Anorexia nervosa -- Case studies Factitious disorders Factitious disorders -- Case studies
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3105 , http://hdl.handle.net/10962/d1004511
- Description: This study is a case-study of a patient who was diagnosed as having co-morbid Anorexia Nervosa and Factitious Disorder. It would appear that central to an understanding of both of these disorders is the patient's disturbed relationship to her own body. The existing literature on co-morbid Factitious Disorder and Anorexia Nervosa is rare, with only three cases published. A careful reading of these cases suggests that in all of these cases, Factitious Disorder may have been the primary diagnosis. In this case there was as overidentification with the patient role, and the patient's anorexic symptoms appeared to serve the function of meeting the patient's acute dependency needs. Thus, the patient's Anorexia Nervosa masked the Factitious Disorder and appeared to be secondary to the Factitious Disorder. It is argued that these disorders share several common dynamics, namely the inability to separate from the mother, high parental expectations as well as the use of the body as a transitional or pre-cursor object. In addition there are some common dynamics in the psychotherapy of these patients. All of these factors suggest that in both these disorders the developmental arrest may be located at a pre-verbal level.
- Full Text:
- Authors: Gaylard, Jeanne
- Date: 2003
- Subjects: Anorexia nervosa Anorexia nervosa -- Case studies Factitious disorders Factitious disorders -- Case studies
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3105 , http://hdl.handle.net/10962/d1004511
- Description: This study is a case-study of a patient who was diagnosed as having co-morbid Anorexia Nervosa and Factitious Disorder. It would appear that central to an understanding of both of these disorders is the patient's disturbed relationship to her own body. The existing literature on co-morbid Factitious Disorder and Anorexia Nervosa is rare, with only three cases published. A careful reading of these cases suggests that in all of these cases, Factitious Disorder may have been the primary diagnosis. In this case there was as overidentification with the patient role, and the patient's anorexic symptoms appeared to serve the function of meeting the patient's acute dependency needs. Thus, the patient's Anorexia Nervosa masked the Factitious Disorder and appeared to be secondary to the Factitious Disorder. It is argued that these disorders share several common dynamics, namely the inability to separate from the mother, high parental expectations as well as the use of the body as a transitional or pre-cursor object. In addition there are some common dynamics in the psychotherapy of these patients. All of these factors suggest that in both these disorders the developmental arrest may be located at a pre-verbal level.
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The bioaccumulation of platinum (IV) from aqueous solution using sulphate reducing bacteria: role of a hydrogenase enzyme
- Authors: Rashamuse, Konanani Justice
- Date: 2003
- Subjects: Sulfur bacteria , Bioremediation , Enzymes -- Metabolism , Platinum , Platinum compounds , Reduction (Chemistry) , Hydrogenation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4003 , http://hdl.handle.net/10962/d1004063 , Sulfur bacteria , Bioremediation , Enzymes -- Metabolism , Platinum , Platinum compounds , Reduction (Chemistry) , Hydrogenation
- Description: The enzymatic reduction of a high-valence form of metals to a low-valence reduced form has been proposed as a strategy to treat water contaminated with a range of metals and radionuclides. Metal reduction by sulphate reducing bacteria (SRB) is carried out either chemically (involving reduction by hydrogen sulphide) or enzymatically (involving redox enzymes such as the hydrogenases). While reduction of metal ions by hydrogen sulphide is well known, the enzymatic mechanism for metal reduction is poorly understood. The aims of this study were to investigate the role of SRB in facilitating platinum removal, and to investigate the role of a hydrogenase in platinum reduction in vitro. In order to avoid precipitation of platinum as platinum sulphide, a resting (non-growing) mixed SRB culture was used. The maximum initial concentration of platinum (IV), which SRB can effectively remove from solution was shown to be 50 mg.l⁻¹. Electron donor studies showed high platinum (IV) uptake in the presence of hydrogen, suggesting that platinum (IV) uptake from solution by SRB requires careful optimization with respect to the correct electron donor. Transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) analysis indicated that platinum was being precipitated in the periplasm, a major area of hydrogenase activity in SRB. Purification of the hydrogenase by ammonium sulphate precipitation (65%), Toyopearl-Super Q 650S ion exchange and Sephacry 1 S-100 size exclusion chromatography revealed that the hydrogenase was monomeric with a molecular weight of 58 KDa, when analyzed by 12% SDS-PAGE. The purified hydrogenase showed optimal temperature and pH at 35°C and 7.5 respectively, and a poor thermal stability. In vitro investigation of platinum reduction by purified hydrogenase from mixed SRB culture showed that hydrogenase reduces platinum only in the presence of hydrogen. Major platinum (IV) reduction was observed when hydrogenase was incubated with cytochrome C₃ (physiological electron carrier in vivo) under hydrogen. The same observations were also noted with industrial effluent. Collectively these findings suggest that in vitro platinum reduction is mediated by hydrogenase with a concerted action of cytochrome C₃ required to shuttle the electron from hydrogenase.
- Full Text:
- Authors: Rashamuse, Konanani Justice
- Date: 2003
- Subjects: Sulfur bacteria , Bioremediation , Enzymes -- Metabolism , Platinum , Platinum compounds , Reduction (Chemistry) , Hydrogenation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4003 , http://hdl.handle.net/10962/d1004063 , Sulfur bacteria , Bioremediation , Enzymes -- Metabolism , Platinum , Platinum compounds , Reduction (Chemistry) , Hydrogenation
- Description: The enzymatic reduction of a high-valence form of metals to a low-valence reduced form has been proposed as a strategy to treat water contaminated with a range of metals and radionuclides. Metal reduction by sulphate reducing bacteria (SRB) is carried out either chemically (involving reduction by hydrogen sulphide) or enzymatically (involving redox enzymes such as the hydrogenases). While reduction of metal ions by hydrogen sulphide is well known, the enzymatic mechanism for metal reduction is poorly understood. The aims of this study were to investigate the role of SRB in facilitating platinum removal, and to investigate the role of a hydrogenase in platinum reduction in vitro. In order to avoid precipitation of platinum as platinum sulphide, a resting (non-growing) mixed SRB culture was used. The maximum initial concentration of platinum (IV), which SRB can effectively remove from solution was shown to be 50 mg.l⁻¹. Electron donor studies showed high platinum (IV) uptake in the presence of hydrogen, suggesting that platinum (IV) uptake from solution by SRB requires careful optimization with respect to the correct electron donor. Transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) analysis indicated that platinum was being precipitated in the periplasm, a major area of hydrogenase activity in SRB. Purification of the hydrogenase by ammonium sulphate precipitation (65%), Toyopearl-Super Q 650S ion exchange and Sephacry 1 S-100 size exclusion chromatography revealed that the hydrogenase was monomeric with a molecular weight of 58 KDa, when analyzed by 12% SDS-PAGE. The purified hydrogenase showed optimal temperature and pH at 35°C and 7.5 respectively, and a poor thermal stability. In vitro investigation of platinum reduction by purified hydrogenase from mixed SRB culture showed that hydrogenase reduces platinum only in the presence of hydrogen. Major platinum (IV) reduction was observed when hydrogenase was incubated with cytochrome C₃ (physiological electron carrier in vivo) under hydrogen. The same observations were also noted with industrial effluent. Collectively these findings suggest that in vitro platinum reduction is mediated by hydrogenase with a concerted action of cytochrome C₃ required to shuttle the electron from hydrogenase.
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The biogeography of the Prosopistomatidae, with a particular emphasis on Southern African species
- Authors: Barber-James, Helen M
- Date: 2003
- Language: English
- Type: Conference paper
- Identifier: vital:6998 , http://hdl.handle.net/10962/d1008378
- Description: The mayfly family Prosopistomatidae consists of the single genus Prosopistoma Latreille. Its known distribution includes species from Africa, Madagascar, the Comores, Europe, the Levant, India, Sri Lanka, China, Vietnam, the Philippines, Malaysia, Sumatra, Java, the Solomon Islands, Papua New Guinea and northern Australia. A tropical Gondwanaland origin of the family has been suggested. No species are currently known from the Neotropical or Nearctic regions, though the family may yet be discovered in northeastern South America, since this region separated from West Africa only c.120 mya. Focussing on southern Africa, several undescribed species have recently been discovered, with interesting implications to the biogeography on a more localised scale. In the western Cape, a prosopistomatid species has been collected in the Olifants River, extending the distribution of this family further south into a more temperate region. Geological evidence indicates that the Olifants River was connected to the Orange River during the Tertiary period. Prosopistomatidae are known from the Orange River today, and the presence of the family in the Olifants River in the western Cape supports the geological evidence of the historical link between these two rivers. Another unexpected discovery was from the Buffalo River in the eastern Cape, at 33ºS. A subtropical zone extends along the east coast of South Africa as a result of the warm Agulhas current offshore, allowing the southerly extension of the distribution of more tropical species. , Research Update on Ephemeroptera & Plecoptera: Proceedings of the Tenth International Conference on Ephemeroptera, 8-11 August 2001, Perugia, Italy. University of Perugia, Perugia, Italy, pp. 263-270.
- Full Text:
- Authors: Barber-James, Helen M
- Date: 2003
- Language: English
- Type: Conference paper
- Identifier: vital:6998 , http://hdl.handle.net/10962/d1008378
- Description: The mayfly family Prosopistomatidae consists of the single genus Prosopistoma Latreille. Its known distribution includes species from Africa, Madagascar, the Comores, Europe, the Levant, India, Sri Lanka, China, Vietnam, the Philippines, Malaysia, Sumatra, Java, the Solomon Islands, Papua New Guinea and northern Australia. A tropical Gondwanaland origin of the family has been suggested. No species are currently known from the Neotropical or Nearctic regions, though the family may yet be discovered in northeastern South America, since this region separated from West Africa only c.120 mya. Focussing on southern Africa, several undescribed species have recently been discovered, with interesting implications to the biogeography on a more localised scale. In the western Cape, a prosopistomatid species has been collected in the Olifants River, extending the distribution of this family further south into a more temperate region. Geological evidence indicates that the Olifants River was connected to the Orange River during the Tertiary period. Prosopistomatidae are known from the Orange River today, and the presence of the family in the Olifants River in the western Cape supports the geological evidence of the historical link between these two rivers. Another unexpected discovery was from the Buffalo River in the eastern Cape, at 33ºS. A subtropical zone extends along the east coast of South Africa as a result of the warm Agulhas current offshore, allowing the southerly extension of the distribution of more tropical species. , Research Update on Ephemeroptera & Plecoptera: Proceedings of the Tenth International Conference on Ephemeroptera, 8-11 August 2001, Perugia, Italy. University of Perugia, Perugia, Italy, pp. 263-270.
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The Boers and the Anglo-Boer War (1899-1902) in the twentieth-century moral imaginary
- Authors: Van Wyk Smith, Malvern
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6120 , http://hdl.handle.net/10962/d1004700
- Description: In 1891 Lord Randolph Churchill, father of the more famous Winston, visited South Africa and the soon-to-be Rhodesia on a trip that was intended to combine big-game hunting with the even more exciting prospects of entering the gold mining business. During the eight months of the visit, Churchill contributed a series of letters to the Daily Graphic on his thoughts and experiences, in one of which he had this to say about the Boers: The Boer farmer personifies useless idleness. Occupying a farm of from six thousand to ten thousand acres, he contents himself with raising a herd of a few hundred head of cattle, which are left almost entirely to the care of the natives whom he employs. It may be asserted, generally with truth, that he never plants a tree, never digs a well, never makes a road, never grows a blade of corn…. He passes his day doing absolutely nothing beyond smoking and drinking coffee. He is perfectly uneducated. With the exception of the Bible, every word of which in its most literal interpretation he believes with fanatical credulity, he never opens a book, he never even reads a newspaper. His simple ignorance is unfathomable, and this in stolid composure he shares with his wife, his sons, his daughters, being proud that his children should grow up as ignorant, as uncultivated, as hopelessly unprogressive as himself. In the winter time he moves with his herd of cattle into the better pastures and milder climate of the low country veldt, and lives as idly and uselessly in his waggon as he does in his farmhouse. The summer sees him returning home, and so on [sic], year after year, generation after generation, the Boer farmer drags out the most ignoble existence ever experienced by a race with any pretensions to civilization. (94–95) The piece caused an outcry, and when a year later Churchill republished the letters as Men, Mines and Animals in South Africa (1892), he attempted to exonerate himself by claiming that these views were intended “to be exclusively confined to…the Dutch population of the Transvaal,” not “generally to the Dutch in South Africa” and went on: “The Dutch settlers in Cape Colony are as worthy of praise as their relatives, the Transvaal Boers, are of blame. The former, loyal, thrifty, industrious, hospitable, liberal are and will, I trust, remain the back-bone of our great colony at the Cape of Good Hope”
- Full Text:
- Authors: Van Wyk Smith, Malvern
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6120 , http://hdl.handle.net/10962/d1004700
- Description: In 1891 Lord Randolph Churchill, father of the more famous Winston, visited South Africa and the soon-to-be Rhodesia on a trip that was intended to combine big-game hunting with the even more exciting prospects of entering the gold mining business. During the eight months of the visit, Churchill contributed a series of letters to the Daily Graphic on his thoughts and experiences, in one of which he had this to say about the Boers: The Boer farmer personifies useless idleness. Occupying a farm of from six thousand to ten thousand acres, he contents himself with raising a herd of a few hundred head of cattle, which are left almost entirely to the care of the natives whom he employs. It may be asserted, generally with truth, that he never plants a tree, never digs a well, never makes a road, never grows a blade of corn…. He passes his day doing absolutely nothing beyond smoking and drinking coffee. He is perfectly uneducated. With the exception of the Bible, every word of which in its most literal interpretation he believes with fanatical credulity, he never opens a book, he never even reads a newspaper. His simple ignorance is unfathomable, and this in stolid composure he shares with his wife, his sons, his daughters, being proud that his children should grow up as ignorant, as uncultivated, as hopelessly unprogressive as himself. In the winter time he moves with his herd of cattle into the better pastures and milder climate of the low country veldt, and lives as idly and uselessly in his waggon as he does in his farmhouse. The summer sees him returning home, and so on [sic], year after year, generation after generation, the Boer farmer drags out the most ignoble existence ever experienced by a race with any pretensions to civilization. (94–95) The piece caused an outcry, and when a year later Churchill republished the letters as Men, Mines and Animals in South Africa (1892), he attempted to exonerate himself by claiming that these views were intended “to be exclusively confined to…the Dutch population of the Transvaal,” not “generally to the Dutch in South Africa” and went on: “The Dutch settlers in Cape Colony are as worthy of praise as their relatives, the Transvaal Boers, are of blame. The former, loyal, thrifty, industrious, hospitable, liberal are and will, I trust, remain the back-bone of our great colony at the Cape of Good Hope”
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The challenges of managing HIV/AIDS counsellors in a rural district in the Eastern Cape, South Africa
- Authors: Gerber, Barbara
- Date: 2003
- Subjects: AIDS (Disease) -- Patients -- Counseling of -- South Africa -- Eastern Cape HIV-positive persons -- Counseling of -- South Africa -- Eastern Cape Counselors -- Supervision of -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3171 , http://hdl.handle.net/10962/d1007799
- Description: The pandemic of HIV/AIDS has challenged several aspects of contemporary social life. HIV/AIDS counselling has developed as a social response to provide support for those infected with the disease. Due to the nature and complexity of the disease, HIV/AIDS counsellors encounter a diversity and intensity of emotions when counselling. A support system that includes effective management and supervision may assist in resolving emotions and reactions that HIV/AIDS counsellors may experience as a result of working with HIV/AIDS clients. This study examines the difficulties that both managers and the HIV/AIDS counsellors at a rural district hospital in the Eastern Cape and its surrounding clinics are faced with, in providing the HIV/AIDS counsellors with the support they need. Engestrom's (1987) model of activity theory was used as a conceptual framework guiding both the analysis and interpretation of the data. This model facilitates the identification of tensions and contradictions thereby opening a space for change and transformation within an activity system. Multiple sources of data collection were used that included focus groups with managers and HIV/AIDS counsellors, interviews with senior hospital staff and an official from the Department of Health, Eastern Cape, and a tour of the rural district hospital. The findings suggest that HIV/AIDS counsellors do not feel supported by their managers. Managers in turn are of the opinion that they do not offer the support the HIV/AIDS counsellors' need. The lack of support is attributed to geographic distances between hospitals and the clinics they serve, lack of available transport and the multiplicity of roles of both managers and the HIV/AIDS counsellors. The pandemic of HIV/AIDS has challenged several aspects of contemporary social life. HIV/AIDS counselling has developed as a social response to provide support for those infected with the disease. Due to the nature and complexity of the disease, HIV/AIDS counsellors encounter a diversity and intensity of emotions when counselling. A support system that includes effective management and supervision may assist in resolving emotions and reactions that HIV/AIDS counsellors may experience as a result of working with HIV/AIDS clients. This study examines the difficulties that both managers and the HIV/AIDS counsellors at a rural district hospital in the Eastern Cape and its surrounding clinics are faced with, in providing the HIV/AIDS counsellors with the support they need. Engestrom's (1987) model of activity theory was used as a conceptual framework guiding both the analysis and interpretation of the data. This model facilitates the identification of tensions and contradictions thereby opening a space for change and transformation within an activity system. Multiple sources of data collection were used that included focus groups with managers and HIV/AIDS counsellors, interviews with senior hospital staff and an official from the Department of Health, Eastern Cape, and a tour of the rural district hospital. The findings suggest that HIV/AIDS counsellors do not feel supported by their managers. Managers in turn are of the opinion that they do not offer the support the HIV/AIDS counsellors' need. The lack of support is attributed to geographic distances between hospitals and the clinics they serve, lack of available transport and the multiplicity of roles of both managers and the HIV/AIDS counsellors. Recommendations include the introduction of self-supervision , peer groupsupervision for HIV/AIDS counsellors.
- Full Text:
- Authors: Gerber, Barbara
- Date: 2003
- Subjects: AIDS (Disease) -- Patients -- Counseling of -- South Africa -- Eastern Cape HIV-positive persons -- Counseling of -- South Africa -- Eastern Cape Counselors -- Supervision of -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3171 , http://hdl.handle.net/10962/d1007799
- Description: The pandemic of HIV/AIDS has challenged several aspects of contemporary social life. HIV/AIDS counselling has developed as a social response to provide support for those infected with the disease. Due to the nature and complexity of the disease, HIV/AIDS counsellors encounter a diversity and intensity of emotions when counselling. A support system that includes effective management and supervision may assist in resolving emotions and reactions that HIV/AIDS counsellors may experience as a result of working with HIV/AIDS clients. This study examines the difficulties that both managers and the HIV/AIDS counsellors at a rural district hospital in the Eastern Cape and its surrounding clinics are faced with, in providing the HIV/AIDS counsellors with the support they need. Engestrom's (1987) model of activity theory was used as a conceptual framework guiding both the analysis and interpretation of the data. This model facilitates the identification of tensions and contradictions thereby opening a space for change and transformation within an activity system. Multiple sources of data collection were used that included focus groups with managers and HIV/AIDS counsellors, interviews with senior hospital staff and an official from the Department of Health, Eastern Cape, and a tour of the rural district hospital. The findings suggest that HIV/AIDS counsellors do not feel supported by their managers. Managers in turn are of the opinion that they do not offer the support the HIV/AIDS counsellors' need. The lack of support is attributed to geographic distances between hospitals and the clinics they serve, lack of available transport and the multiplicity of roles of both managers and the HIV/AIDS counsellors. The pandemic of HIV/AIDS has challenged several aspects of contemporary social life. HIV/AIDS counselling has developed as a social response to provide support for those infected with the disease. Due to the nature and complexity of the disease, HIV/AIDS counsellors encounter a diversity and intensity of emotions when counselling. A support system that includes effective management and supervision may assist in resolving emotions and reactions that HIV/AIDS counsellors may experience as a result of working with HIV/AIDS clients. This study examines the difficulties that both managers and the HIV/AIDS counsellors at a rural district hospital in the Eastern Cape and its surrounding clinics are faced with, in providing the HIV/AIDS counsellors with the support they need. Engestrom's (1987) model of activity theory was used as a conceptual framework guiding both the analysis and interpretation of the data. This model facilitates the identification of tensions and contradictions thereby opening a space for change and transformation within an activity system. Multiple sources of data collection were used that included focus groups with managers and HIV/AIDS counsellors, interviews with senior hospital staff and an official from the Department of Health, Eastern Cape, and a tour of the rural district hospital. The findings suggest that HIV/AIDS counsellors do not feel supported by their managers. Managers in turn are of the opinion that they do not offer the support the HIV/AIDS counsellors' need. The lack of support is attributed to geographic distances between hospitals and the clinics they serve, lack of available transport and the multiplicity of roles of both managers and the HIV/AIDS counsellors. Recommendations include the introduction of self-supervision , peer groupsupervision for HIV/AIDS counsellors.
- Full Text:
The comparative case study of the use of English and isiXhosa as medium of instruction in a grade five class
- Authors: Mngqibisa, Mandla Daniel
- Date: 2003
- Subjects: English language -- Study and teaching (Elementary) -- South Africa Xhosa language -- Study and teaching (Elementary) -- South Africa Education, Bilingual Language and education -- South Africa Language policy -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1455 , http://hdl.handle.net/10962/d1003336
- Description: The aim of this study was to compare the quality of oral interaction between a grade 5class and their teacher when either English or isiXhosa was used as medium ofinstruction in two different lessons and of their writing which arose out of the lessons. The research was carried out within the interpretive paradigm and took the form of a casestudy. The researcher took the stance of being a non-participant observer. A variety oftechniques were used to collect data, namely, piloting, video recording and transcribing lessons, observing and making field notes, questionnaires and an interview. The interview was recorded and transcribed by the researcher. The two lessons were transcribed and analysed. Also the learners’ writing was analysed. The findings of this study showed that learners have little competence in English compared to isiXhosa. As a result most of them used short and vague sentences when responding to and discussing pictures in English. They also used short and simple sentences when writing in English compared toisiXhosa. Although this is a small-scale study it is recommended that the school’s language policy is revised and teachers are equipped with necessary skills, which would help them teach English to second language learners effectively. It is also recommended that the learners’ first language continue to be well taught even if it is no longer the classroom language.
- Full Text:
- Authors: Mngqibisa, Mandla Daniel
- Date: 2003
- Subjects: English language -- Study and teaching (Elementary) -- South Africa Xhosa language -- Study and teaching (Elementary) -- South Africa Education, Bilingual Language and education -- South Africa Language policy -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1455 , http://hdl.handle.net/10962/d1003336
- Description: The aim of this study was to compare the quality of oral interaction between a grade 5class and their teacher when either English or isiXhosa was used as medium ofinstruction in two different lessons and of their writing which arose out of the lessons. The research was carried out within the interpretive paradigm and took the form of a casestudy. The researcher took the stance of being a non-participant observer. A variety oftechniques were used to collect data, namely, piloting, video recording and transcribing lessons, observing and making field notes, questionnaires and an interview. The interview was recorded and transcribed by the researcher. The two lessons were transcribed and analysed. Also the learners’ writing was analysed. The findings of this study showed that learners have little competence in English compared to isiXhosa. As a result most of them used short and vague sentences when responding to and discussing pictures in English. They also used short and simple sentences when writing in English compared toisiXhosa. Although this is a small-scale study it is recommended that the school’s language policy is revised and teachers are equipped with necessary skills, which would help them teach English to second language learners effectively. It is also recommended that the learners’ first language continue to be well taught even if it is no longer the classroom language.
- Full Text:
The concentrations of the noble metals in Southern African flood-type basalts and MORB: implications for petrogenesis and magmatic sulphide exploration
- Maier, Wolfgand D, Barnes, Sarah-Jane, Marsh, Julian S
- Authors: Maier, Wolfgand D , Barnes, Sarah-Jane , Marsh, Julian S
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150573 , vital:38985 , https://doi.org/10.1007/s00410-003-0480-z
- Description: Concentrations of the platinum-group elements have been determined in several suites of southern African flood-type basalts and mid-ocean ridge basalt (MORB), covering some 3 Ga of geologic evolution and including the Etendeka, Karoo, Soutpansberg, Machadodorp, Hekpoort, Ventersdorp and Dominion magmas.
- Full Text: false
- Authors: Maier, Wolfgand D , Barnes, Sarah-Jane , Marsh, Julian S
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150573 , vital:38985 , https://doi.org/10.1007/s00410-003-0480-z
- Description: Concentrations of the platinum-group elements have been determined in several suites of southern African flood-type basalts and mid-ocean ridge basalt (MORB), covering some 3 Ga of geologic evolution and including the Etendeka, Karoo, Soutpansberg, Machadodorp, Hekpoort, Ventersdorp and Dominion magmas.
- Full Text: false
The conjugalisation of reproduction in South African teenage pregnancy literature
- Authors: Macleod, Catriona I
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6266 , http://hdl.handle.net/10962/d1008265 , https://orcid.org/0000-0003-0992-3525
- Description: The “conjugalisation of reproduction”, in which childbearing is legitimated only within a marital alliance, underlies some of the pathologisation of the single, female-headed household in the pre-democracy South African teenage pregnancy literature. I utilise a poststructural feminist framework that draws on elements of Derrida’s and Foucault’s work to analyse the conjugalisation of reproduction in South African research. The conjugalisation of reproduction relies on (1) the insidious “unwed” signifier which interpenetrates the term “teenage pregnancy”, allowing the scientific censure of non-marital adolescent re-production without the invocation of moralisation, and (2) the fixation of the husband-wife and parents-children axes of alliance as the main elements for the deployment of sexuality and reproduction in the form of the family. Pregnant teenagers are, in Derridean terms, undecidables: they are neither children (owing to their reproductive status) nor adults (owing to their age), but simultaneously both. Marriage is the authority that decides them, allowing them to join the ranks of adult reproductive subjects.
- Full Text:
- Authors: Macleod, Catriona I
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6266 , http://hdl.handle.net/10962/d1008265 , https://orcid.org/0000-0003-0992-3525
- Description: The “conjugalisation of reproduction”, in which childbearing is legitimated only within a marital alliance, underlies some of the pathologisation of the single, female-headed household in the pre-democracy South African teenage pregnancy literature. I utilise a poststructural feminist framework that draws on elements of Derrida’s and Foucault’s work to analyse the conjugalisation of reproduction in South African research. The conjugalisation of reproduction relies on (1) the insidious “unwed” signifier which interpenetrates the term “teenage pregnancy”, allowing the scientific censure of non-marital adolescent re-production without the invocation of moralisation, and (2) the fixation of the husband-wife and parents-children axes of alliance as the main elements for the deployment of sexuality and reproduction in the form of the family. Pregnant teenagers are, in Derridean terms, undecidables: they are neither children (owing to their reproductive status) nor adults (owing to their age), but simultaneously both. Marriage is the authority that decides them, allowing them to join the ranks of adult reproductive subjects.
- Full Text:
The construction of masculinities: male university students' talk about women and heterosexual relationships
- Authors: Minnaar, Benita
- Date: 2003
- Subjects: Masculinity , Men -- Identity , Men -- South Africa , Men -- Conduct of life , Discourse analysis , Heterosexuality -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3020 , http://hdl.handle.net/10962/d1002529 , Masculinity , Men -- Identity , Men -- South Africa , Men -- Conduct of life , Discourse analysis , Heterosexuality -- South Africa
- Description: This article examines the talk of male Psychology students about women and heterosexual relationships in all-male discussion groups. Four vignettes depicting difficult situations in heterosexual relationships were used to initiate discussion. Eight men attending a historically black university participated in the group discussions, which were facilitated by a male postgraduate Psychology student. The study explored masculine identity construction by identifying interpretive repertoires deployed by respondents to construct and account for themselves and their social worlds, within the context of discussions about relationships with women. Three interpretive repertoires of masculinity: the male-as- breadwinner/provider, male-as-protector and the "New Man" repertoire were identified. The complex and contradictory nature of masculine identity construction is highlighted. Drawing on the work of Hollway (1984), two discourses of heterosexuality were also identified: the have/hold discourse and the permissive discourse. The invocation of the "New Man" repertoire and pro-feminist discourses of heterosexuality in the men's talk may signify a move towards more enlightened and less oppressive constructions of masculinity, heterosexuality and gender.
- Full Text:
- Authors: Minnaar, Benita
- Date: 2003
- Subjects: Masculinity , Men -- Identity , Men -- South Africa , Men -- Conduct of life , Discourse analysis , Heterosexuality -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3020 , http://hdl.handle.net/10962/d1002529 , Masculinity , Men -- Identity , Men -- South Africa , Men -- Conduct of life , Discourse analysis , Heterosexuality -- South Africa
- Description: This article examines the talk of male Psychology students about women and heterosexual relationships in all-male discussion groups. Four vignettes depicting difficult situations in heterosexual relationships were used to initiate discussion. Eight men attending a historically black university participated in the group discussions, which were facilitated by a male postgraduate Psychology student. The study explored masculine identity construction by identifying interpretive repertoires deployed by respondents to construct and account for themselves and their social worlds, within the context of discussions about relationships with women. Three interpretive repertoires of masculinity: the male-as- breadwinner/provider, male-as-protector and the "New Man" repertoire were identified. The complex and contradictory nature of masculine identity construction is highlighted. Drawing on the work of Hollway (1984), two discourses of heterosexuality were also identified: the have/hold discourse and the permissive discourse. The invocation of the "New Man" repertoire and pro-feminist discourses of heterosexuality in the men's talk may signify a move towards more enlightened and less oppressive constructions of masculinity, heterosexuality and gender.
- Full Text:
The construction of news texts on 'peace' an analysis of Sunday Times' coverage of the Peace Summits in the Democratic Republic of Congo (August 1998 - January 2001)
- Moiloa, Makhotso Mamasole Ruth
- Authors: Moiloa, Makhotso Mamasole Ruth
- Date: 2003
- Subjects: Sunday Times (Johannesburg, South Africa) , Congo (Democratic Republic) -- In mass media , Journalism -- Objectivity -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3467 , http://hdl.handle.net/10962/d1002922 , Sunday Times (Johannesburg, South Africa) , Congo (Democratic Republic) -- In mass media , Journalism -- Objectivity -- South Africa
- Description: This study examines the construction of news texts on peace and the peace process in the Democratic Republic of the Congo (DRC) in Sunday Times articles dating from August 1998 to January 2001. Peace is an ideological frame that is applied to a complex process that Muller (2000) argues involves and employs a variety of dynamics: diplomacy, economics, force/military intervention and propaganda. As a consequence, different interest groups and nations define peace in different ways. But whatever the definition, the common objective is to restore normalcy via a ceasefire. Peace as a phenomenon has been heightened and sustained by repetitive media attention, thus effectively separating it from international politics (i.e. colonialism of the mind, economy and land), and firmly locating it as a matter of not just public concern, but of international public concern. Using the cultural studies approach to a study of media texts provides a rich foundation for this study. Textual analysis of the articles explores themes and participation and places emphasis on the display of patterns of belief and value that are encoded in the language. What results is a sustained examination of media texts within their socio-cultural and historical context. This study s findings challenge the claim that the media report peace objectively and on its own terms. In particular, the study denies that the Sunday Times objectively, fairly and truthfully reported the experience and process in the DRC between August 1998 and January 2001. Instead it finds that the newspaper constructed a particular understanding of peace, peace talks and the peace process, characterised by repetition, ritualisation and personalisation. Furthermore, this study proposes - and echoes the call for - an alternative news reporting model that will enhance audiences understandings of conflict and its resolution, thereby enhancing the quality of their life.
- Full Text:
- Authors: Moiloa, Makhotso Mamasole Ruth
- Date: 2003
- Subjects: Sunday Times (Johannesburg, South Africa) , Congo (Democratic Republic) -- In mass media , Journalism -- Objectivity -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3467 , http://hdl.handle.net/10962/d1002922 , Sunday Times (Johannesburg, South Africa) , Congo (Democratic Republic) -- In mass media , Journalism -- Objectivity -- South Africa
- Description: This study examines the construction of news texts on peace and the peace process in the Democratic Republic of the Congo (DRC) in Sunday Times articles dating from August 1998 to January 2001. Peace is an ideological frame that is applied to a complex process that Muller (2000) argues involves and employs a variety of dynamics: diplomacy, economics, force/military intervention and propaganda. As a consequence, different interest groups and nations define peace in different ways. But whatever the definition, the common objective is to restore normalcy via a ceasefire. Peace as a phenomenon has been heightened and sustained by repetitive media attention, thus effectively separating it from international politics (i.e. colonialism of the mind, economy and land), and firmly locating it as a matter of not just public concern, but of international public concern. Using the cultural studies approach to a study of media texts provides a rich foundation for this study. Textual analysis of the articles explores themes and participation and places emphasis on the display of patterns of belief and value that are encoded in the language. What results is a sustained examination of media texts within their socio-cultural and historical context. This study s findings challenge the claim that the media report peace objectively and on its own terms. In particular, the study denies that the Sunday Times objectively, fairly and truthfully reported the experience and process in the DRC between August 1998 and January 2001. Instead it finds that the newspaper constructed a particular understanding of peace, peace talks and the peace process, characterised by repetition, ritualisation and personalisation. Furthermore, this study proposes - and echoes the call for - an alternative news reporting model that will enhance audiences understandings of conflict and its resolution, thereby enhancing the quality of their life.
- Full Text:
The decline of agriculture in rural Transkei: ʺthe case of Mission Location in Butterworthʺ
- Authors: Ngcaba, Siyanda Vincent
- Date: 2003
- Subjects: Agriculture -- South Africa -- Transkei , Land use -- South Africa -- Transkei , Land tenure -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3296 , http://hdl.handle.net/10962/d1003084 , Agriculture -- South Africa -- Transkei , Land use -- South Africa -- Transkei , Land tenure -- South Africa -- Transkei
- Description: The following dissertation sets out to investigate the decline of agriculture in Mission location at Butterworth, Transkei, using the Rehabilitation Scheme as a benchmark. The scheme was introduced in 1945 to combat soil erosion and improve agriculture in the African reserve areas, as the South African government claimed. The dissertation argues that this claim by the government served to mask the real intentions behind the scheme namely, to regiment the migrant labour system by depriving as many Africans as possible of productive land so that they were unable to fully subsist by means of agriculture. This is further shown by analysing the impact of the Rehabilitation scheme in Mission location in which a substantial number of people lost arable land as a result of the implementation of the scheme in 1945. These people were consequently denied the wherewithal to subsist by agriculture. Moreover, the efforts of the government resulted to a modernisation of agriculture by making it more cash-based- for example through the introduction of fencing, the need for tractors as a result of a decline in stock numbers (in part as a result of stock culling). Most people could hardly afford this type of agriculture and were consequently forced off the land. The dissertation concludes that indeed the decline of agriculture in Mission location can be linked to the changing agricultural and land-holding practices brought about by the government- especially the introduction of the Rehabilitation scheme.
- Full Text:
- Authors: Ngcaba, Siyanda Vincent
- Date: 2003
- Subjects: Agriculture -- South Africa -- Transkei , Land use -- South Africa -- Transkei , Land tenure -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3296 , http://hdl.handle.net/10962/d1003084 , Agriculture -- South Africa -- Transkei , Land use -- South Africa -- Transkei , Land tenure -- South Africa -- Transkei
- Description: The following dissertation sets out to investigate the decline of agriculture in Mission location at Butterworth, Transkei, using the Rehabilitation Scheme as a benchmark. The scheme was introduced in 1945 to combat soil erosion and improve agriculture in the African reserve areas, as the South African government claimed. The dissertation argues that this claim by the government served to mask the real intentions behind the scheme namely, to regiment the migrant labour system by depriving as many Africans as possible of productive land so that they were unable to fully subsist by means of agriculture. This is further shown by analysing the impact of the Rehabilitation scheme in Mission location in which a substantial number of people lost arable land as a result of the implementation of the scheme in 1945. These people were consequently denied the wherewithal to subsist by agriculture. Moreover, the efforts of the government resulted to a modernisation of agriculture by making it more cash-based- for example through the introduction of fencing, the need for tractors as a result of a decline in stock numbers (in part as a result of stock culling). Most people could hardly afford this type of agriculture and were consequently forced off the land. The dissertation concludes that indeed the decline of agriculture in Mission location can be linked to the changing agricultural and land-holding practices brought about by the government- especially the introduction of the Rehabilitation scheme.
- Full Text:
The development and evaluation of Cryptophlebia Leucotreta granulovirus (CrleGV) as a biological control agent for the management of false codling moth, Cryptophlebia Leucotreta, on citrus
- Authors: Moore, Sean Douglas
- Date: 2003
- Subjects: Cryptophlebia leucotreta Cryptophlebia leucotreta -- Control Pests -- Biological control Citrus -- Diseases and pests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3942 , http://hdl.handle.net/10962/d1004001
- Description: A granulovirus isolated from Cryptophlebia leucotreta larvae was shown through restriction endonuclease analysis to be a novel strain (CrleGV-SA). No more than one isolate could be identified from a laboratory culture of C. leucotreta. However, a preliminary examination of restricted DNA profiles of isolates from different geographical regions indicated some minor differences. In surface dose bioassays on artificial diet, LC50 and LC90 values with neonate larvae were estimated to be 4.095 x 103 OBs/ml and 1.185 x 105 OBs/ml respectively. LT50 and LT90 values with neonate larvae were estimated to be 4 days 22 h and 7 days 8 h, respectively. Detached fruit (navel orange) bioassays with neonate larvae indicated that virus concentrations that are likely to be effective in the field range from 1.08 x 107 to 3.819 x 1010 OBs/ml. In surface dose bioassays with fifth instar larvae LC50 and LC90 values were estimated to be 2.678 x 107 OBs/ml and 9.118 x 109 OBs/ml respectively. LT50 and LT90 values were estimated to be 7 days 17 h and 9 days 8 h, respectively. A new artificial diet for mass rearing the host was developed. Microbial contamination of diet was significantly reduced by adding nipagin and sorbic acid to the diet and by surface sterilising C. leucotreta eggs with Sporekill. Almost 20 % more eggs were produced from moths reared on the new diet compared to moths reared on the old diet. A further 9 % improvement in egg production and a reduction in the labour required to produce eggs, was made with the development of a new oviposition cage attached to the moth eclosion box. Virus was mass produced in fifth instar C. leucotreta larvae by surface inoculating diet with the LC90. When 300 individuals were placed onto inoculated diet, 56 % of them were recovered six to 11 days later as infected larvae. Mean larval equivalents was 1.158 x 1011 OBs/larva. When larvae and diet were harvested together, highest yields of virus were achieved at eight days after inoculation. Microbial contamination in semi-purified preparations of CrleGV ranged from 176211 to 433594 (OB:CFU ratio). Half-life of CrleGV in the field was estimated to be less than 1 day on the northern aspect of trees and between 3 - 6 days on the southern aspect. Original activity remaining (OAR) of the virus dropped below 50 % after 5 days on the northern aspect of trees and was still at 69 % on the southern aspect of trees after 3 weeks. In field trials, CrleGV reduced C. leucotreta infestation of navel oranges by up to 60 % for a period of 39 days. CrleGV in combination with augmentation of the C. leucotreta egg parasitoid, Trichogrammatoidea cryptophlebiae, reduced infestation by 70 %. The integration of CrleGV into an integrated pest management (IPM) system for the management of C. leucotreta on citrus is proposed.
- Full Text:
- Authors: Moore, Sean Douglas
- Date: 2003
- Subjects: Cryptophlebia leucotreta Cryptophlebia leucotreta -- Control Pests -- Biological control Citrus -- Diseases and pests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3942 , http://hdl.handle.net/10962/d1004001
- Description: A granulovirus isolated from Cryptophlebia leucotreta larvae was shown through restriction endonuclease analysis to be a novel strain (CrleGV-SA). No more than one isolate could be identified from a laboratory culture of C. leucotreta. However, a preliminary examination of restricted DNA profiles of isolates from different geographical regions indicated some minor differences. In surface dose bioassays on artificial diet, LC50 and LC90 values with neonate larvae were estimated to be 4.095 x 103 OBs/ml and 1.185 x 105 OBs/ml respectively. LT50 and LT90 values with neonate larvae were estimated to be 4 days 22 h and 7 days 8 h, respectively. Detached fruit (navel orange) bioassays with neonate larvae indicated that virus concentrations that are likely to be effective in the field range from 1.08 x 107 to 3.819 x 1010 OBs/ml. In surface dose bioassays with fifth instar larvae LC50 and LC90 values were estimated to be 2.678 x 107 OBs/ml and 9.118 x 109 OBs/ml respectively. LT50 and LT90 values were estimated to be 7 days 17 h and 9 days 8 h, respectively. A new artificial diet for mass rearing the host was developed. Microbial contamination of diet was significantly reduced by adding nipagin and sorbic acid to the diet and by surface sterilising C. leucotreta eggs with Sporekill. Almost 20 % more eggs were produced from moths reared on the new diet compared to moths reared on the old diet. A further 9 % improvement in egg production and a reduction in the labour required to produce eggs, was made with the development of a new oviposition cage attached to the moth eclosion box. Virus was mass produced in fifth instar C. leucotreta larvae by surface inoculating diet with the LC90. When 300 individuals were placed onto inoculated diet, 56 % of them were recovered six to 11 days later as infected larvae. Mean larval equivalents was 1.158 x 1011 OBs/larva. When larvae and diet were harvested together, highest yields of virus were achieved at eight days after inoculation. Microbial contamination in semi-purified preparations of CrleGV ranged from 176211 to 433594 (OB:CFU ratio). Half-life of CrleGV in the field was estimated to be less than 1 day on the northern aspect of trees and between 3 - 6 days on the southern aspect. Original activity remaining (OAR) of the virus dropped below 50 % after 5 days on the northern aspect of trees and was still at 69 % on the southern aspect of trees after 3 weeks. In field trials, CrleGV reduced C. leucotreta infestation of navel oranges by up to 60 % for a period of 39 days. CrleGV in combination with augmentation of the C. leucotreta egg parasitoid, Trichogrammatoidea cryptophlebiae, reduced infestation by 70 %. The integration of CrleGV into an integrated pest management (IPM) system for the management of C. leucotreta on citrus is proposed.
- Full Text:
The development of a baculovirus expression system for the production of Helicoverpa armigera stunt virus capsids for use in the encapsidation of foreign molecules
- Mosisili, Kekeletso Mpho Thakane
- Authors: Mosisili, Kekeletso Mpho Thakane
- Date: 2003
- Subjects: Helicoverpa armigera , Fall armyworm , Baculoviruses , Insects -- Viruses , RNA -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4088 , http://hdl.handle.net/10962/d1007700 , Helicoverpa armigera , Fall armyworm , Baculoviruses , Insects -- Viruses , RNA -- Analysis
- Description: The capsid protein of Helicoverpa armigera stunt virus (HaSV) a T=4 insect virus was expressed in Spodoptera frugiperda 9 cells using a baculovirus vector. When the insect cells were infected at a high MOl the expressed coat protein assembled into virus-like particles (VLPs) that spontaneously underwent maturation and were morphologically indistinguishable from wild-type HaSV. The VLPs were electron dense when viewed under EM and encapsidated their coat protein mRNA. When Sf9 cells were infected at a low multiplicity of infection (MOl) the expressed capsid protein assembled into procapsids that did not spontaneously undergo maturation. These procapsids underwent autoproteolytic maturation cleavage when they were treated with an acidic buffer. The procapsids were used in the encapsidation of a FITC labelled peptide. The peptide encapsidating VLPs showed an increase in their buoyant density that was not collaborated by an increase in the concentration of the FITC labelled peptide detected when these samples were compared to control samples with similar buoyant densities.
- Full Text:
- Authors: Mosisili, Kekeletso Mpho Thakane
- Date: 2003
- Subjects: Helicoverpa armigera , Fall armyworm , Baculoviruses , Insects -- Viruses , RNA -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4088 , http://hdl.handle.net/10962/d1007700 , Helicoverpa armigera , Fall armyworm , Baculoviruses , Insects -- Viruses , RNA -- Analysis
- Description: The capsid protein of Helicoverpa armigera stunt virus (HaSV) a T=4 insect virus was expressed in Spodoptera frugiperda 9 cells using a baculovirus vector. When the insect cells were infected at a high MOl the expressed coat protein assembled into virus-like particles (VLPs) that spontaneously underwent maturation and were morphologically indistinguishable from wild-type HaSV. The VLPs were electron dense when viewed under EM and encapsidated their coat protein mRNA. When Sf9 cells were infected at a low multiplicity of infection (MOl) the expressed capsid protein assembled into procapsids that did not spontaneously undergo maturation. These procapsids underwent autoproteolytic maturation cleavage when they were treated with an acidic buffer. The procapsids were used in the encapsidation of a FITC labelled peptide. The peptide encapsidating VLPs showed an increase in their buoyant density that was not collaborated by an increase in the concentration of the FITC labelled peptide detected when these samples were compared to control samples with similar buoyant densities.
- Full Text:
The development of an instrument to measure intrapreneurship: entrepreneurship within the corporate setting
- Authors: Hill, Marguerite Elizabeth
- Date: 2003
- Subjects: Entrepreneurship , Psychology, Industrial , Organizational change
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2991 , http://hdl.handle.net/10962/d1002500 , Entrepreneurship , Psychology, Industrial , Organizational change
- Description: “Intrapreneurship is not a choice, it is the only survival attitude” (Pinchot, 2000, p.75). In 1985 Pinchot coined the term ‘intrapreneurship’, short for intra-corporate entrepreneurship, which describes the practice of entrepreneurship within organisations. Intrapreneurship is increasingly becoming a term used in the business world to describe organisations that are willing to pursue opportunities, initiate actions, and emphasise new, innovative products or services. Due to the dynamic nature of modern organisations, it is imperative that organisations and their managers remain receptive to new ideas, approaches and attitudes. It is therefore the belief that rapid and cost-effective innovation is the primary source of lasting competitive advantage in the twenty-first century, leaving organisations no alternative but to become intrapreneurial or cease to exist. This thesis focuses on this need and examines ways in which intrapreneurship can be measured in organisations in order to provide a benchmark for further organisational development. A questionnaire (known as the Intrapreneurial Intensity Index) was designed and distributed to a sample of 500 employees working in large South African organisations, which classified themselves as ‘forward-thinking’ and aimed for an intrapreneurial ‘type of thinking’. The results obtained from these questionnaires underwent item analysis, after which the questionnaire was redesigned in an electronic format. A pilot case study was then conducted in order to test the reliability of the instrument. Finally the questionnaire was redistributed to a sample of six organisations that are viewed as being ‘intrapreneurial’ and two that are regarded as being ‘non-intrapreneurial’. The data from this sample was used to test the validity of the Intrapreneurial Intensity Index and to demonstrate its application. This study resulted in an instrument that can be used to ascertain the intensity of intrapreneurship present in a large organisation. Specifically, this instrument can provide an overall view of the organisation’s intrapreneurial ability, as well as identify the specific areas in the organisation that require change or modification in order to become more intrapreneurial. This instrument provides a valuable means of identifying areas in need of organisational change, by determining an organisation’s intrapreneurial properties in the organisation’s core areas.
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- Authors: Hill, Marguerite Elizabeth
- Date: 2003
- Subjects: Entrepreneurship , Psychology, Industrial , Organizational change
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2991 , http://hdl.handle.net/10962/d1002500 , Entrepreneurship , Psychology, Industrial , Organizational change
- Description: “Intrapreneurship is not a choice, it is the only survival attitude” (Pinchot, 2000, p.75). In 1985 Pinchot coined the term ‘intrapreneurship’, short for intra-corporate entrepreneurship, which describes the practice of entrepreneurship within organisations. Intrapreneurship is increasingly becoming a term used in the business world to describe organisations that are willing to pursue opportunities, initiate actions, and emphasise new, innovative products or services. Due to the dynamic nature of modern organisations, it is imperative that organisations and their managers remain receptive to new ideas, approaches and attitudes. It is therefore the belief that rapid and cost-effective innovation is the primary source of lasting competitive advantage in the twenty-first century, leaving organisations no alternative but to become intrapreneurial or cease to exist. This thesis focuses on this need and examines ways in which intrapreneurship can be measured in organisations in order to provide a benchmark for further organisational development. A questionnaire (known as the Intrapreneurial Intensity Index) was designed and distributed to a sample of 500 employees working in large South African organisations, which classified themselves as ‘forward-thinking’ and aimed for an intrapreneurial ‘type of thinking’. The results obtained from these questionnaires underwent item analysis, after which the questionnaire was redesigned in an electronic format. A pilot case study was then conducted in order to test the reliability of the instrument. Finally the questionnaire was redistributed to a sample of six organisations that are viewed as being ‘intrapreneurial’ and two that are regarded as being ‘non-intrapreneurial’. The data from this sample was used to test the validity of the Intrapreneurial Intensity Index and to demonstrate its application. This study resulted in an instrument that can be used to ascertain the intensity of intrapreneurship present in a large organisation. Specifically, this instrument can provide an overall view of the organisation’s intrapreneurial ability, as well as identify the specific areas in the organisation that require change or modification in order to become more intrapreneurial. This instrument provides a valuable means of identifying areas in need of organisational change, by determining an organisation’s intrapreneurial properties in the organisation’s core areas.
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The diamondback moth, Plutella xylostella (L.), (Lepidoptera: Plutellidae) and its biological control in the Eastern Cape Province, South Africa
- Authors: Smith, Tamara Jane
- Date: 2003
- Subjects: Plutellidae Plutellidae -- South Africa -- Eastern Cape Insect pests -- Biological control -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5626 , http://hdl.handle.net/10962/d1004742
- Description: The diamondback moth, Plutella xylostella (L.), is a pest on crucifer crops worldwide, damaging the leaves, florets and seed pods of many crucifers including cabbage, cauliflower, broccoli and canola. It has been controlled using broad-spectrum insecticides, but this has led to a rapid build-up of insecticide resistance. In the Grahamstown area of the Eastern Cape Province, South Africa, diamondback moth showed resistance to cypermethrin (a pyrethroid) on commercially grown cabbages. Therefore it is imperative that other methods of control be adopted, including both cultural control and biological control using parasitoids, and that these are incorporated into an Integrated Pest Management (IPM) programme. The diamondback moth and its parasitoids were monitored weekly from April 1997 to November 1999 at three sites near Grahamstown. One site was a commercial farm with an active insecticide spraying program; the others were unsprayed. Infestation levels were highest during spring (September to November) and autumn (March to May). Nine species of parasitoids were associated with the diamondback moth, with abundances being highest over spring and early summer (September to December). Cotesia plutellae (Kurdjumov) dominated the sprayed site, while the unsprayed sites yielded a complex of parasitoids, including C. plutellae, Diadegma mollipla (Holmgren), Diadromus collaris Gravenhorst and Oomyzus sokolowsldi (Kurdjumov). Parasitism levels ranged between 10 and 90%. There was a large amount of site-to-site and year-to-year variation. Parasitoids were an effective mortality factor against the diamondback moth. The effects of temperature on development and mortality, and of field size and non-crop plants on the distribution of diamondback moth and its parasitoids, were investigated. The results show that high temperatures can depress pest populations, and that the size and surroundings of fields can be manipulated to improve cultural control of the diamondback moth. Suggestions for effective rPM in the Eastern Cape Province include a reduction in insecticide applications, the use of bioinsecticides, for example Bacillus thuringiensis Berliner (Bt) and the encouragement of indigenous parasitoids by planting suitable nectar sources. Cultural control methods are also important and involve removal of cabbage refuse after harvest, management of wild crucifers around cabbage fields, scouting and monitoring the moth population and determining the optimal field size to assist with control by parasitoids.
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- Authors: Smith, Tamara Jane
- Date: 2003
- Subjects: Plutellidae Plutellidae -- South Africa -- Eastern Cape Insect pests -- Biological control -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5626 , http://hdl.handle.net/10962/d1004742
- Description: The diamondback moth, Plutella xylostella (L.), is a pest on crucifer crops worldwide, damaging the leaves, florets and seed pods of many crucifers including cabbage, cauliflower, broccoli and canola. It has been controlled using broad-spectrum insecticides, but this has led to a rapid build-up of insecticide resistance. In the Grahamstown area of the Eastern Cape Province, South Africa, diamondback moth showed resistance to cypermethrin (a pyrethroid) on commercially grown cabbages. Therefore it is imperative that other methods of control be adopted, including both cultural control and biological control using parasitoids, and that these are incorporated into an Integrated Pest Management (IPM) programme. The diamondback moth and its parasitoids were monitored weekly from April 1997 to November 1999 at three sites near Grahamstown. One site was a commercial farm with an active insecticide spraying program; the others were unsprayed. Infestation levels were highest during spring (September to November) and autumn (March to May). Nine species of parasitoids were associated with the diamondback moth, with abundances being highest over spring and early summer (September to December). Cotesia plutellae (Kurdjumov) dominated the sprayed site, while the unsprayed sites yielded a complex of parasitoids, including C. plutellae, Diadegma mollipla (Holmgren), Diadromus collaris Gravenhorst and Oomyzus sokolowsldi (Kurdjumov). Parasitism levels ranged between 10 and 90%. There was a large amount of site-to-site and year-to-year variation. Parasitoids were an effective mortality factor against the diamondback moth. The effects of temperature on development and mortality, and of field size and non-crop plants on the distribution of diamondback moth and its parasitoids, were investigated. The results show that high temperatures can depress pest populations, and that the size and surroundings of fields can be manipulated to improve cultural control of the diamondback moth. Suggestions for effective rPM in the Eastern Cape Province include a reduction in insecticide applications, the use of bioinsecticides, for example Bacillus thuringiensis Berliner (Bt) and the encouragement of indigenous parasitoids by planting suitable nectar sources. Cultural control methods are also important and involve removal of cabbage refuse after harvest, management of wild crucifers around cabbage fields, scouting and monitoring the moth population and determining the optimal field size to assist with control by parasitoids.
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The diet of a small group of extralimital giraffe
- Parker, Daniel M, Bernard, Ric T F, Colvin, S A
- Authors: Parker, Daniel M , Bernard, Ric T F , Colvin, S A
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6950 , http://hdl.handle.net/10962/d1011980
- Description: Giraffe are extralimital in the Eastern Cape Province, South Africa where recent local introductions have persisted despite limited research into their impact on the indigenous flora. The diet of 15 giraffe at the Shamwari Game Reserve was recorded by direct observation during summer (March/April) and winter (July/August) 2001, quantifying diet by frequency of occurrence (individual records scored and expressed as a percentage of the total). Preference indices were also calculated. Habitat use was measured by the number of hours giraffe fed in different habitats. The diet comprised of 14 plant species, the most important species being Rhus longispina (47.9%), Acacia karroo (25.7%) and Euclea undulata (17.6%). Importance of R. longispina, A. karroo and Tarchonanthus camphoratus fluctuated seasonally. Rhus longispina was more important in winter with a corresponding decrease in feeding on A. karroo. Tarchonanthus camphoratus was only consumed during summer. Acacia karroo thickets (previously disturbed areas) were utilized most (summer 12 h; winter 9 h), with alternative habitats utilized more often in winter than in summer. We suggest that the seasonal fluctuation in the importance of R. longispina & A. karroo reflects the deciduous nature of A. karroo.
- Full Text:
- Authors: Parker, Daniel M , Bernard, Ric T F , Colvin, S A
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6950 , http://hdl.handle.net/10962/d1011980
- Description: Giraffe are extralimital in the Eastern Cape Province, South Africa where recent local introductions have persisted despite limited research into their impact on the indigenous flora. The diet of 15 giraffe at the Shamwari Game Reserve was recorded by direct observation during summer (March/April) and winter (July/August) 2001, quantifying diet by frequency of occurrence (individual records scored and expressed as a percentage of the total). Preference indices were also calculated. Habitat use was measured by the number of hours giraffe fed in different habitats. The diet comprised of 14 plant species, the most important species being Rhus longispina (47.9%), Acacia karroo (25.7%) and Euclea undulata (17.6%). Importance of R. longispina, A. karroo and Tarchonanthus camphoratus fluctuated seasonally. Rhus longispina was more important in winter with a corresponding decrease in feeding on A. karroo. Tarchonanthus camphoratus was only consumed during summer. Acacia karroo thickets (previously disturbed areas) were utilized most (summer 12 h; winter 9 h), with alternative habitats utilized more often in winter than in summer. We suggest that the seasonal fluctuation in the importance of R. longispina & A. karroo reflects the deciduous nature of A. karroo.
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