Biochemical evaluation of Tulbaghia violacea harv.rhizomes in diet induced hypercholestrolemic rats
- Olorunnisola, Olubukola Sinbad
- Authors: Olorunnisola, Olubukola Sinbad
- Date: 2012
- Subjects: Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD (Biochemistry)
- Identifier: vital:11273 , http://hdl.handle.net/10353/d1006900 , Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Description: Discovery of cheap, nontoxic and readily available antiatherosclerotic drugs is an extraordinary challenge in this modern world. Atherosclerosis and cardiovascular diseases have been predicted to be the leading cause of death by the year 2030. Hence, this thesis was designed to search for plant (s) with anti-atherogenic properties, investigate its possible side effects and extrapolate its likely mechanism(s) of action. An ethnobotanical survey was employed in identification of locally important plants used for the management and treatment of cardiovascular diseases and its predisposing factors in Nkonkobe Municipality, Eastern Cape in South Africa. Information on the names of plants, their parts used and methods of preparation was collected through a questionnaire which was administered to herbalists, traditional healers and rural dwellers. The most frequently used plant (Rhizomes of Tulbaghia violacea Harv.) was investigated for toxicity using brine shrimp lethality (in vitro) and in vivo toxicity test (acute and subchronic) on rats to determine safety dosage. The in vitro antioxidant and free radical scavenging activity of the plant was investigated using models such as 1,1-diphenyl-2- picrylhydrazyl (DPPH), superoxide anions, hydrogen peroxide (H2O2), nitric oxide (NO), 2,2’- azinobis [3-ethylbenzothiazoline-6-sulfonic acid] diammonium salt (ABTS), lipid peroxidation inhibition and the ferric reducing agent. Phytochemical content and the effect of oral administration of fresh methanolic extract rhizomes of Tulbaghia violacea (250, 500 mg/kg. bwt/day) on Lipid peroxidation (TBARS), serum and tissue antioxidant enzymes in normal, hypercholesterolemic and diet induced atherogenic rats were also assessed. More so, the potential of the extract (250 and 500 mg/kg. bwt) to protect against atherogenic diet (4 percentage cholesterol 1 pecentage cholic acid and 0.5 percentage thiouracil) induced fatty streaks formation, dyslipidemia, oxidative stress and endothelial dysfunction was also investigated. Ethnobotanical study revealed that 19 plant species are used for the treatment of heart related diseases in the Municipality. 53 percentage of the plants mentioned were used for the management of chest pain, 47 percentage for high blood pressure, 42 percent for heart disease, 16 percentage for stroke and 11 percentage for the treatment of hypercholesterolemia. Tulbaghia violacea was repeatedly mentioned as the plant species used for the treatment of high blood pressure and predisposing factors in the study area. The brine shrimp cytotoxicity test revealed that fresh, dried methanolic extracts and essential oil of the T. violacea exhibited a high degree of cytotoxic activity with IC50 values of 18.18 (fresh) and 19.24 (dried) μg/ml. An IC50 value of 12. 59 μg/ml was obtained for the essential oil of the plant. The low cytotoxicity values obtained, suggested that rhizome of T. violacea may serve as a potential source of antimicrobial and anticancer agents. In vivo acute study of single oral administration of 5g/kg dose does not produce mortality or significant behavioral changes during 14 days observation. In the sub-chronic study, the extract (250, 500 mg/kg/bwt/ day) administered for a period of 28 days showed no mortality or morbidity. The weekly body and organ weight of the rats showed no significant differences between the control and the rats treated with the extract. The extract at all doses does not show any effect on of biomarkers of liver or renal damage. However, a significant decrease in the activity of ƔGT was observed in the extract treated groups. Hematological evaluation revealed that oral administration of fresh methanolic extracts of rhizomes of T. violacea does not cause anaemia or leucocytosis in the animals. Furthermore, histopathology results of the internal organs revealed no detectable inflammation. These results demonstrated that the rhizome extract of T. violacea was potentially safe for consumption orally even in chronic concentration. In vitro antioxidant evaluation showed that the essential oil, fresh and dried methanolic extracts exhibited potent antioxidant activities in a concentration dependent manner. Phytochemical investigation reveals that the fresh and the dry extract of RTV are rich in flavonoid, flavonol, phenols, tannin and proanthocyanidin, while the essential oil contained dimethy disulfide, dimethyl trisulfide, (methyl methylthio) methyl, 2,4-dithiapentane (11.35 percent) and (methylthio) acetic acid, 2- (methylthio) ethanol, 3-(methylthio) - and propanenitrile (7.20 percent). The fresh extract had higher radicals scavenging activity than the essential oil or dried extract, with 50 percentage inhibition of DPPH, hydrogen peroxide and lipid peroxidation at a concentration of 35.0 ± 0.12, 19.3 ± 0.11 and 17.9 ± 0.15 μg/ml respectively. Oral administration of methanolic extract of RTV in 125, 250 and 500 mg/kg to female Wistar rats significantly inhibited reduction of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). The extracts also inhibited (p< 0.05) lipid peroxidation in normal, high cholesterol and diet induced atherosclerosis fed rats in a dose dependant manner. Also the extract (250 and 500 mg/kg/bwt/day) caused a significant (p<0.05) improvement in body weight of treated animals compared with untreated hypercholesterolemia control rats. The extracts also protected significantly (p<0.05) against atherogenic diet induced liver damage or fatty streaks formation in the aorta as revealed by histological examination. The anti-cholesterolemia and anti-atherosclerotic activities of the extract compared favorably well with standard drugs Gemfibrozil and Atorvastatin respectively. Conclusively, rhizomes of T. violacea possess significant anti-atherogenic activity and its mechanism of action(s) may be due to its antioxidant and anti-hypercholesterolemia properties. The results of this study also suggested that rhizome of T. violacea is relatively safe for human consumption and it may be used as an alternative to garlic.
- Full Text:
- Date Issued: 2012
- Authors: Olorunnisola, Olubukola Sinbad
- Date: 2012
- Subjects: Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD (Biochemistry)
- Identifier: vital:11273 , http://hdl.handle.net/10353/d1006900 , Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Description: Discovery of cheap, nontoxic and readily available antiatherosclerotic drugs is an extraordinary challenge in this modern world. Atherosclerosis and cardiovascular diseases have been predicted to be the leading cause of death by the year 2030. Hence, this thesis was designed to search for plant (s) with anti-atherogenic properties, investigate its possible side effects and extrapolate its likely mechanism(s) of action. An ethnobotanical survey was employed in identification of locally important plants used for the management and treatment of cardiovascular diseases and its predisposing factors in Nkonkobe Municipality, Eastern Cape in South Africa. Information on the names of plants, their parts used and methods of preparation was collected through a questionnaire which was administered to herbalists, traditional healers and rural dwellers. The most frequently used plant (Rhizomes of Tulbaghia violacea Harv.) was investigated for toxicity using brine shrimp lethality (in vitro) and in vivo toxicity test (acute and subchronic) on rats to determine safety dosage. The in vitro antioxidant and free radical scavenging activity of the plant was investigated using models such as 1,1-diphenyl-2- picrylhydrazyl (DPPH), superoxide anions, hydrogen peroxide (H2O2), nitric oxide (NO), 2,2’- azinobis [3-ethylbenzothiazoline-6-sulfonic acid] diammonium salt (ABTS), lipid peroxidation inhibition and the ferric reducing agent. Phytochemical content and the effect of oral administration of fresh methanolic extract rhizomes of Tulbaghia violacea (250, 500 mg/kg. bwt/day) on Lipid peroxidation (TBARS), serum and tissue antioxidant enzymes in normal, hypercholesterolemic and diet induced atherogenic rats were also assessed. More so, the potential of the extract (250 and 500 mg/kg. bwt) to protect against atherogenic diet (4 percentage cholesterol 1 pecentage cholic acid and 0.5 percentage thiouracil) induced fatty streaks formation, dyslipidemia, oxidative stress and endothelial dysfunction was also investigated. Ethnobotanical study revealed that 19 plant species are used for the treatment of heart related diseases in the Municipality. 53 percentage of the plants mentioned were used for the management of chest pain, 47 percentage for high blood pressure, 42 percent for heart disease, 16 percentage for stroke and 11 percentage for the treatment of hypercholesterolemia. Tulbaghia violacea was repeatedly mentioned as the plant species used for the treatment of high blood pressure and predisposing factors in the study area. The brine shrimp cytotoxicity test revealed that fresh, dried methanolic extracts and essential oil of the T. violacea exhibited a high degree of cytotoxic activity with IC50 values of 18.18 (fresh) and 19.24 (dried) μg/ml. An IC50 value of 12. 59 μg/ml was obtained for the essential oil of the plant. The low cytotoxicity values obtained, suggested that rhizome of T. violacea may serve as a potential source of antimicrobial and anticancer agents. In vivo acute study of single oral administration of 5g/kg dose does not produce mortality or significant behavioral changes during 14 days observation. In the sub-chronic study, the extract (250, 500 mg/kg/bwt/ day) administered for a period of 28 days showed no mortality or morbidity. The weekly body and organ weight of the rats showed no significant differences between the control and the rats treated with the extract. The extract at all doses does not show any effect on of biomarkers of liver or renal damage. However, a significant decrease in the activity of ƔGT was observed in the extract treated groups. Hematological evaluation revealed that oral administration of fresh methanolic extracts of rhizomes of T. violacea does not cause anaemia or leucocytosis in the animals. Furthermore, histopathology results of the internal organs revealed no detectable inflammation. These results demonstrated that the rhizome extract of T. violacea was potentially safe for consumption orally even in chronic concentration. In vitro antioxidant evaluation showed that the essential oil, fresh and dried methanolic extracts exhibited potent antioxidant activities in a concentration dependent manner. Phytochemical investigation reveals that the fresh and the dry extract of RTV are rich in flavonoid, flavonol, phenols, tannin and proanthocyanidin, while the essential oil contained dimethy disulfide, dimethyl trisulfide, (methyl methylthio) methyl, 2,4-dithiapentane (11.35 percent) and (methylthio) acetic acid, 2- (methylthio) ethanol, 3-(methylthio) - and propanenitrile (7.20 percent). The fresh extract had higher radicals scavenging activity than the essential oil or dried extract, with 50 percentage inhibition of DPPH, hydrogen peroxide and lipid peroxidation at a concentration of 35.0 ± 0.12, 19.3 ± 0.11 and 17.9 ± 0.15 μg/ml respectively. Oral administration of methanolic extract of RTV in 125, 250 and 500 mg/kg to female Wistar rats significantly inhibited reduction of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). The extracts also inhibited (p< 0.05) lipid peroxidation in normal, high cholesterol and diet induced atherosclerosis fed rats in a dose dependant manner. Also the extract (250 and 500 mg/kg/bwt/day) caused a significant (p<0.05) improvement in body weight of treated animals compared with untreated hypercholesterolemia control rats. The extracts also protected significantly (p<0.05) against atherogenic diet induced liver damage or fatty streaks formation in the aorta as revealed by histological examination. The anti-cholesterolemia and anti-atherosclerotic activities of the extract compared favorably well with standard drugs Gemfibrozil and Atorvastatin respectively. Conclusively, rhizomes of T. violacea possess significant anti-atherogenic activity and its mechanism of action(s) may be due to its antioxidant and anti-hypercholesterolemia properties. The results of this study also suggested that rhizome of T. violacea is relatively safe for human consumption and it may be used as an alternative to garlic.
- Full Text:
- Date Issued: 2012
Aspects Allocentristes de l’Humanisme dans l’Univers Romanesque de Williams Sassine
- Authors: Dami, Emmanuel Naancin
- Date: 2018
- Subjects: Sassine, Williams, 1944-1997 -- Criticism and interpretation , Guinean fiction (French) -- 20th century -- History and criticism , Humanism in literature , Human beings in literature , Postcolonialism in literature , Existentialism in literature
- Language: French , English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/61957 , vital:28089
- Description: The human being, his behaviour and more importantly, his very essence have, for time immemorial, proven to be enigmatic to many a man and to researchers in particular. Consequently, the need for a thorough and more profound understanding of man has made him the epicentre of epistemic investigations across many academic disciplines. This, unfortunately, does not seem to have shaded bright lights on the grey areas bordering on his nature to his behavior. This, in turn, opens up other windows requiring further probes. For instance, proponents of the Neo-classical economic school contend that the human being is homo oeconomicus. This implies that man is intrinsically egocentric and a rational being whose decisions are based on informed choices driven by his urge for maximal utility geared towards his personal satisfaction (O’Boyle 2009; Caruso 2012). This stance invalidates man’s ability to do ‘disinterested good’ in any form. African francophone literature is replete with different and diverse images of man, his behaviour and existential conditions: sufferings and struggles. It, therefore, constitutes, inter alia, a laboratory in which researchers undertake investigative endeavours. This thesis beams its floodlights on the allocentric aspects of humanism in the novels of Williams Sassine. Thus, using the phenomenological and ‘clavieniste’ lenses as overarching operational theories, the thesis investigates Sassine’s novels with the view to shading a ray of light on the ‘humanistic man’ especially the allocentric dimensions of his nature and comportment. Emphasis is laid on the motives and motivations underlying the individual and the in-group struggle of the sassinien heroes in the emancipation of their society from the shackles of colonial and postcolonial domination, exploitation and subjugation resulting in self-determination and the subsequent disenchantment. Furthermore, the thesis examines the nature and character of human charity, generosity and sacrifices among the characters in the novels. In conclusion, the thesis establishes, through an x-ray of the nature of actions and decisions of certain characters in the novels, the examination of the conscious and subconscious intentions underlying these same actions and decisions which, on a face value, are apparently altruistic, that the sassinien heroes’ efforts and sacrifices are geared towards the common and greater good. This invariably means that man is, indeed, capable of posing disinterested acts of charity and bringing succour, devoid of any ulterior motives for personal gain, to his fellow humans. The position of the Neo-classical economists is consequently over-assuming, sweeping and tad generalizing. The sassinien characters have demonstrated beyond reasonable doubt that they are humanists. Their nature, the remote and immediate causes of their fights, the goals and objectives of their struggles and their spirit of abnegation have indeed proven that “human beings have the right and the responsibility to give meaning and shape to their own lives. [They have stood] for the building of a more humane society through an ethics based on the human and other natural values in a spirit of reason and free inquiry through human capabilities” (AHA 2017 : 3).
- Full Text:
- Date Issued: 2018
- Authors: Dami, Emmanuel Naancin
- Date: 2018
- Subjects: Sassine, Williams, 1944-1997 -- Criticism and interpretation , Guinean fiction (French) -- 20th century -- History and criticism , Humanism in literature , Human beings in literature , Postcolonialism in literature , Existentialism in literature
- Language: French , English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/61957 , vital:28089
- Description: The human being, his behaviour and more importantly, his very essence have, for time immemorial, proven to be enigmatic to many a man and to researchers in particular. Consequently, the need for a thorough and more profound understanding of man has made him the epicentre of epistemic investigations across many academic disciplines. This, unfortunately, does not seem to have shaded bright lights on the grey areas bordering on his nature to his behavior. This, in turn, opens up other windows requiring further probes. For instance, proponents of the Neo-classical economic school contend that the human being is homo oeconomicus. This implies that man is intrinsically egocentric and a rational being whose decisions are based on informed choices driven by his urge for maximal utility geared towards his personal satisfaction (O’Boyle 2009; Caruso 2012). This stance invalidates man’s ability to do ‘disinterested good’ in any form. African francophone literature is replete with different and diverse images of man, his behaviour and existential conditions: sufferings and struggles. It, therefore, constitutes, inter alia, a laboratory in which researchers undertake investigative endeavours. This thesis beams its floodlights on the allocentric aspects of humanism in the novels of Williams Sassine. Thus, using the phenomenological and ‘clavieniste’ lenses as overarching operational theories, the thesis investigates Sassine’s novels with the view to shading a ray of light on the ‘humanistic man’ especially the allocentric dimensions of his nature and comportment. Emphasis is laid on the motives and motivations underlying the individual and the in-group struggle of the sassinien heroes in the emancipation of their society from the shackles of colonial and postcolonial domination, exploitation and subjugation resulting in self-determination and the subsequent disenchantment. Furthermore, the thesis examines the nature and character of human charity, generosity and sacrifices among the characters in the novels. In conclusion, the thesis establishes, through an x-ray of the nature of actions and decisions of certain characters in the novels, the examination of the conscious and subconscious intentions underlying these same actions and decisions which, on a face value, are apparently altruistic, that the sassinien heroes’ efforts and sacrifices are geared towards the common and greater good. This invariably means that man is, indeed, capable of posing disinterested acts of charity and bringing succour, devoid of any ulterior motives for personal gain, to his fellow humans. The position of the Neo-classical economists is consequently over-assuming, sweeping and tad generalizing. The sassinien characters have demonstrated beyond reasonable doubt that they are humanists. Their nature, the remote and immediate causes of their fights, the goals and objectives of their struggles and their spirit of abnegation have indeed proven that “human beings have the right and the responsibility to give meaning and shape to their own lives. [They have stood] for the building of a more humane society through an ethics based on the human and other natural values in a spirit of reason and free inquiry through human capabilities” (AHA 2017 : 3).
- Full Text:
- Date Issued: 2018
Electrochemical studies of metal-ligand interactions and of metal binding proteins
- Authors: Limson, Janice Leigh
- Date: 1999
- Subjects: Electrochemical analysis , Metals -- Analysis , Proteins -- Analysis , Electrochemistry -- Technique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4551 , http://hdl.handle.net/10962/d1018239
- Description: Electrochemical methods were researched for the analysis of metals, proteins and the identification of metal binding proteins. Adsorptive cathodic stripping voltamrnetry for metal analysis combines the inherent sensitivity of electrochemical techniques with the specificity of ligands for the nonfaradaic preconcentration of analytes at the electrode. The utility of catechol, resorcinol, 4-methylcatechol and 4-t-butylcatechol as ligands was explored for the sensitive analysis of copper, bismuth, cadmium and lead on a mercury film glassy carbon electrode. Metal complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed the highest current responses with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper. The electroanalysis of cysteine and cysteine containing proteins at carbon electrodes are impaired by slow electron transfer rates at carbon electrodes, exhibiting high overpotentials, greater than 1 V vs Ag! Agel. Metallophthalocyanines have been shown to promote the electrocatalysis of cysteine at lowered potentials. Chemical modification of electrodes with appropriate modifiers is a means of incorporating specificity into electroanalysis, with applications in electrocatalysis. A glassy carbon electrode was modified by electrodeposition of cobalt (II) tetrasulphophthalocyanine [Co(II)TSPct to produce a chemically modified glassy carbon electrode (CMGCE). The CoTSPc-CMGCE catalysed the oxidation of cysteine in the pH range 1 to 10. The significance of this electrode is an application for analysis of proteins at biological pH's. A biscyanoruthenium(II) phthalocyanine CMGCE catalysed the oxidation of cysteine at 0.43 V vs Ag/AgCl a significant lowering in the overpotential for the oxidation of cysteine. Metallothionein, a metal binding protein, is believed to be involved in metal homeostasis and detoxification in the peripheral organs of living systems. A method for the quantitative determination of this protein utilising its high cysteine content was presented. At pH 8.4 Tris-HCl buffer, and using a CoTSPc-CMGCE modified by electrodeposition of the modifier, the anodic peaks for the oxidation of metallothionein was observed at 0. 90 V vs Ag/ AgCI. Ferredoxin is a simple iron-sulphur protein. One tenth of its residues are cysteine. Ferredoxin is involved in simple electron transfer processes during photosynthesis and respiration. Electrochemical studies of spinach ferredoxin were conducted at a CoTSPc-CMGCE. Anodic currents for the oxidation of the cysteine fragment of ferredoxin was observed at 0.85 V vs Ag/AgCl in HEPES buffer at pH 7.4, representing a new method for analysis of this protein. Voltammetric studies of its ferric/ferrous transition have shown quasi-reversible waves atE~ -0.62 V vs Ag/AgCl only in the presence of promoters. At a CoTSPc-CMGCE, a cathodic wave attributed to the reduction of Fe(III)/Fe(II) was observed at Epc -0.34 V vs Ag/AgCl. This represents an alternative method for voltammetric studies of the ferric/ferrous transition at significantly lowered potentials. Melatonin, a pineal gland hormone functions m setting and entraining circadian rhythms and in neuroprotection as a free radical scavenger and general antioxidant. Using adsorptive cathodic stripping voltammetry, the binding affinities of melatonin, serotonin and tryptophan for metals, were measured. The results showed that the following metal complexes were formed: aluminium with melatonin, serotonin and tryptophan; cadmium with melatonin and tryptophan; copper with melatonin and serotonin; iron (III) with melatonin and serotonin; lead with melatonin, tryptophan and serotonin, zinc with melatonin and tryptophan and iron (II) with tryptophan. The studies suggest a further role for melatonin in the reduction of free radical generation and in metal detoxification and may explain the accumulation of aluminium in Alzheimer's disease.
- Full Text:
- Date Issued: 1999
- Authors: Limson, Janice Leigh
- Date: 1999
- Subjects: Electrochemical analysis , Metals -- Analysis , Proteins -- Analysis , Electrochemistry -- Technique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4551 , http://hdl.handle.net/10962/d1018239
- Description: Electrochemical methods were researched for the analysis of metals, proteins and the identification of metal binding proteins. Adsorptive cathodic stripping voltamrnetry for metal analysis combines the inherent sensitivity of electrochemical techniques with the specificity of ligands for the nonfaradaic preconcentration of analytes at the electrode. The utility of catechol, resorcinol, 4-methylcatechol and 4-t-butylcatechol as ligands was explored for the sensitive analysis of copper, bismuth, cadmium and lead on a mercury film glassy carbon electrode. Metal complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed the highest current responses with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper. The electroanalysis of cysteine and cysteine containing proteins at carbon electrodes are impaired by slow electron transfer rates at carbon electrodes, exhibiting high overpotentials, greater than 1 V vs Ag! Agel. Metallophthalocyanines have been shown to promote the electrocatalysis of cysteine at lowered potentials. Chemical modification of electrodes with appropriate modifiers is a means of incorporating specificity into electroanalysis, with applications in electrocatalysis. A glassy carbon electrode was modified by electrodeposition of cobalt (II) tetrasulphophthalocyanine [Co(II)TSPct to produce a chemically modified glassy carbon electrode (CMGCE). The CoTSPc-CMGCE catalysed the oxidation of cysteine in the pH range 1 to 10. The significance of this electrode is an application for analysis of proteins at biological pH's. A biscyanoruthenium(II) phthalocyanine CMGCE catalysed the oxidation of cysteine at 0.43 V vs Ag/AgCl a significant lowering in the overpotential for the oxidation of cysteine. Metallothionein, a metal binding protein, is believed to be involved in metal homeostasis and detoxification in the peripheral organs of living systems. A method for the quantitative determination of this protein utilising its high cysteine content was presented. At pH 8.4 Tris-HCl buffer, and using a CoTSPc-CMGCE modified by electrodeposition of the modifier, the anodic peaks for the oxidation of metallothionein was observed at 0. 90 V vs Ag/ AgCI. Ferredoxin is a simple iron-sulphur protein. One tenth of its residues are cysteine. Ferredoxin is involved in simple electron transfer processes during photosynthesis and respiration. Electrochemical studies of spinach ferredoxin were conducted at a CoTSPc-CMGCE. Anodic currents for the oxidation of the cysteine fragment of ferredoxin was observed at 0.85 V vs Ag/AgCl in HEPES buffer at pH 7.4, representing a new method for analysis of this protein. Voltammetric studies of its ferric/ferrous transition have shown quasi-reversible waves atE~ -0.62 V vs Ag/AgCl only in the presence of promoters. At a CoTSPc-CMGCE, a cathodic wave attributed to the reduction of Fe(III)/Fe(II) was observed at Epc -0.34 V vs Ag/AgCl. This represents an alternative method for voltammetric studies of the ferric/ferrous transition at significantly lowered potentials. Melatonin, a pineal gland hormone functions m setting and entraining circadian rhythms and in neuroprotection as a free radical scavenger and general antioxidant. Using adsorptive cathodic stripping voltammetry, the binding affinities of melatonin, serotonin and tryptophan for metals, were measured. The results showed that the following metal complexes were formed: aluminium with melatonin, serotonin and tryptophan; cadmium with melatonin and tryptophan; copper with melatonin and serotonin; iron (III) with melatonin and serotonin; lead with melatonin, tryptophan and serotonin, zinc with melatonin and tryptophan and iron (II) with tryptophan. The studies suggest a further role for melatonin in the reduction of free radical generation and in metal detoxification and may explain the accumulation of aluminium in Alzheimer's disease.
- Full Text:
- Date Issued: 1999
Customary marriage and family practices that discriminate against amaXhosa women: a critical study of selected isixhosa literary text
- Authors: Mbatyoti, Pheliwe Yvonne
- Date: 2019
- Subjects: Forced marriage -- South Africa -- Eastern Cape Customary law -- South Africa Xhosa (African people) -- Social life and customs
- Language: English
- Type: Thesis , Doctoral , D Litt et Phil (African Studies)
- Identifier: http://hdl.handle.net/10353/10736 , vital:35731
- Description: In many parts of Africa, the cultural practices and customs that were in use over the ages are still largely in place today. Many of these practices discriminate against individuals and compromise their human rights, particularly the rights of African women. The aim of this investigation is to study customary marital practices among the amaXhosa in order to establish their effect on modern amaXhosa society. In addition, this includes other discriminatory practices, such as the diminished status of wedded women. Within the study, the social status of women before and after 1994 is dealt with as depicted in the selected texts. The study further determines the current social status of married women under the current dispensation and finds out whether the rights of married women are sufficiently recognised in the texts under discussion. It is clear therefore that whilst Africa has made good progress on the political front, the same cannot be said for some of the cultural values that are still adhered to in the present age. This applies in particular to the rights of women in an African society. Globally, women and girls suffer the harmful and life-threatening effects of discriminatory traditional and cultural practices that continue under the guise of social, cultural and religious ceremonies. In the democratic South Africa, there is growing concern and awareness that some cultural practices are harmful to women and girls. The study analyses a number of texts namely, novels and drama, that were published before and after the 1994 era in South Africa with aims and objectives being outlined in Chapter 1. Chapter 2 is devoted to the theoretical framework, which includes the general theory pertaining to the status of women, feminism and human rights. Secondly, it deals with African theory pertaining to the status of African women as well as their rights; finally, it reflects on the role of women in societies where traditional marriage custom is still in use. Chapter 3 analyses the depiction of customary marriage as a theme in isiXhosa prose before and after 1994. Chapter 4 examines the depiction of customary marriage in v isiXhosa drama before and after 1994 and focuses more on human rights elements. Chapter 5 summarises the arguments distilled from the analysed works. The researcher came to the conclusion that the practice of forced marriage does not occur in amaXhosa society only but it is also found on a wider scale on the rest of the African continent and beyond. The study was concluded with a set of recommendations that were made to combat the scourge of anti-feminism that is found in modern society.
- Full Text:
- Date Issued: 2019
- Authors: Mbatyoti, Pheliwe Yvonne
- Date: 2019
- Subjects: Forced marriage -- South Africa -- Eastern Cape Customary law -- South Africa Xhosa (African people) -- Social life and customs
- Language: English
- Type: Thesis , Doctoral , D Litt et Phil (African Studies)
- Identifier: http://hdl.handle.net/10353/10736 , vital:35731
- Description: In many parts of Africa, the cultural practices and customs that were in use over the ages are still largely in place today. Many of these practices discriminate against individuals and compromise their human rights, particularly the rights of African women. The aim of this investigation is to study customary marital practices among the amaXhosa in order to establish their effect on modern amaXhosa society. In addition, this includes other discriminatory practices, such as the diminished status of wedded women. Within the study, the social status of women before and after 1994 is dealt with as depicted in the selected texts. The study further determines the current social status of married women under the current dispensation and finds out whether the rights of married women are sufficiently recognised in the texts under discussion. It is clear therefore that whilst Africa has made good progress on the political front, the same cannot be said for some of the cultural values that are still adhered to in the present age. This applies in particular to the rights of women in an African society. Globally, women and girls suffer the harmful and life-threatening effects of discriminatory traditional and cultural practices that continue under the guise of social, cultural and religious ceremonies. In the democratic South Africa, there is growing concern and awareness that some cultural practices are harmful to women and girls. The study analyses a number of texts namely, novels and drama, that were published before and after the 1994 era in South Africa with aims and objectives being outlined in Chapter 1. Chapter 2 is devoted to the theoretical framework, which includes the general theory pertaining to the status of women, feminism and human rights. Secondly, it deals with African theory pertaining to the status of African women as well as their rights; finally, it reflects on the role of women in societies where traditional marriage custom is still in use. Chapter 3 analyses the depiction of customary marriage as a theme in isiXhosa prose before and after 1994. Chapter 4 examines the depiction of customary marriage in v isiXhosa drama before and after 1994 and focuses more on human rights elements. Chapter 5 summarises the arguments distilled from the analysed works. The researcher came to the conclusion that the practice of forced marriage does not occur in amaXhosa society only but it is also found on a wider scale on the rest of the African continent and beyond. The study was concluded with a set of recommendations that were made to combat the scourge of anti-feminism that is found in modern society.
- Full Text:
- Date Issued: 2019
The South African anaphora: the development of the anaphora of the South African Eucharistic rite
- Authors: Hinchliff, Peter Bingham
- Date: 1958
- Subjects: Church of the Province of South Africa. Book of common prayer -- History -- Sources Eucharistic prayers Eucharistic prayers -- Anglican Communion Anglican Communion -- Liturgy -- History -- Sources Anglican Communion -- South Africa -- Liturgy -- History -- Sources.
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1260 , http://hdl.handle.net/10962/d1012293
- Description: The Prayer Book of the Church of England reached South Africa as a part of the establishment of the British Administration at the Cape. In its new environment it obviously required some revision. The Book of 1662 reflected the political and social conditions of its time. lt was designed for a Church not immediately concerned with missionary work amongst heathen peoples but directly established under the Crown. The circumstances of a Church in the colonies, particularly when the colonies became self-governing, required some modernisation of language, some omission and adaptation of old prayers and some addition of new ones. Yet the Church appears to have been wary of attempting anything more than this, and it was especially reluctant to make any revision which might imply a doctrinal change. The consecration prayer in the liturgy -'our incomparable liturgy' - was particularly sacrosanct by virtue of long use and the accretion of sentimental associations. Revision of this part of the book would naturally be slow and hesitant and this is the revision with which we are concerned - the most interesting and important part of the history of the South African Prayer Book. Chapter 1, p. 6.
- Full Text:
- Date Issued: 1958
- Authors: Hinchliff, Peter Bingham
- Date: 1958
- Subjects: Church of the Province of South Africa. Book of common prayer -- History -- Sources Eucharistic prayers Eucharistic prayers -- Anglican Communion Anglican Communion -- Liturgy -- History -- Sources Anglican Communion -- South Africa -- Liturgy -- History -- Sources.
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1260 , http://hdl.handle.net/10962/d1012293
- Description: The Prayer Book of the Church of England reached South Africa as a part of the establishment of the British Administration at the Cape. In its new environment it obviously required some revision. The Book of 1662 reflected the political and social conditions of its time. lt was designed for a Church not immediately concerned with missionary work amongst heathen peoples but directly established under the Crown. The circumstances of a Church in the colonies, particularly when the colonies became self-governing, required some modernisation of language, some omission and adaptation of old prayers and some addition of new ones. Yet the Church appears to have been wary of attempting anything more than this, and it was especially reluctant to make any revision which might imply a doctrinal change. The consecration prayer in the liturgy -'our incomparable liturgy' - was particularly sacrosanct by virtue of long use and the accretion of sentimental associations. Revision of this part of the book would naturally be slow and hesitant and this is the revision with which we are concerned - the most interesting and important part of the history of the South African Prayer Book. Chapter 1, p. 6.
- Full Text:
- Date Issued: 1958
Understanding climate change and rural livelihoods in Zimbabwe: adaptation by communal farmers in Ngundu, Chivi District
- Authors: Nciizah, Elinah
- Date: 2020
- Subjects: Agriculture -- Zimbabwe , Agriculture -- Climatic factors -- Chivi District (Zimbabwe) , Chivi District (Zimbabwe) -- Rural conditions
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/118765 , vital:34666
- Description: Climate change and variability is a global phenomenon which has deeply localised patterns, dynamics and effects. Amongst those people who are particularly vulnerable to climate change effects are small-scale farmers who are dependent in large part on rain-fed agriculture in pursuing their livelihoods. This is true of small-scale farmers in contemporary Zimbabwe and, more specifically, farmers in communal areas. At the same time, at international and national levels, there are attempts currently to minimise the effects of, and to adapt to, climate change. However, adaptation measures also exist at local levels amongst small-scale farmers, such as communal farmers in Zimbabwe. In this context, as its main objective, this thesis examines climate change and small-scale farmer livelihood adaptation to climate change with specific reference to communal farmers in Chivi District in Zimbabwe and, in particular, in Ward 25 which is popularly known as Ngundu. In pursuing this main objective, a number of subsidiary objectives are addressed, including a focus on the established livelihoods of Ngundu farmers, the perceptions and concerns of Ngundu farmers about climate change, the coping and adaptation measures of Ngundu farmers, and the enablements and constraints which affect attempts by Ngundu farmers to adopt such measures. The fieldwork for the thesis involved a diverse array of research methods, such as a questionnaire survey, life-history interviews, key informant interviews, focus group discussions and transect walks. In terms of theoretical framing, the thesis makes use of both middle-level theory (the Sustainable Livelihoods Framework) and macro-theory in the form of the sociological work of Margaret Archer. Combined, these two theories allow for a focus on both structure and agency when seeking to understand livelihood adaptations to climate change by communal farmers in Ngundu. The thesis concludes that there are massive constraints inhibiting adaptation measures by Ngundu farmers, but that this should not distract from the deep, often historically-embedded, concerns of Ngundu farmers about climate change and the multiple ways in which they express agency in and through adaptation and coping activities. It also highlights the need for more specifically sociological investigations of climate change and small-scale farmer adaptation, as well as the need for localised studies which are able to identify and analyse the specificities of adaptation.
- Full Text:
- Date Issued: 2020
- Authors: Nciizah, Elinah
- Date: 2020
- Subjects: Agriculture -- Zimbabwe , Agriculture -- Climatic factors -- Chivi District (Zimbabwe) , Chivi District (Zimbabwe) -- Rural conditions
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/118765 , vital:34666
- Description: Climate change and variability is a global phenomenon which has deeply localised patterns, dynamics and effects. Amongst those people who are particularly vulnerable to climate change effects are small-scale farmers who are dependent in large part on rain-fed agriculture in pursuing their livelihoods. This is true of small-scale farmers in contemporary Zimbabwe and, more specifically, farmers in communal areas. At the same time, at international and national levels, there are attempts currently to minimise the effects of, and to adapt to, climate change. However, adaptation measures also exist at local levels amongst small-scale farmers, such as communal farmers in Zimbabwe. In this context, as its main objective, this thesis examines climate change and small-scale farmer livelihood adaptation to climate change with specific reference to communal farmers in Chivi District in Zimbabwe and, in particular, in Ward 25 which is popularly known as Ngundu. In pursuing this main objective, a number of subsidiary objectives are addressed, including a focus on the established livelihoods of Ngundu farmers, the perceptions and concerns of Ngundu farmers about climate change, the coping and adaptation measures of Ngundu farmers, and the enablements and constraints which affect attempts by Ngundu farmers to adopt such measures. The fieldwork for the thesis involved a diverse array of research methods, such as a questionnaire survey, life-history interviews, key informant interviews, focus group discussions and transect walks. In terms of theoretical framing, the thesis makes use of both middle-level theory (the Sustainable Livelihoods Framework) and macro-theory in the form of the sociological work of Margaret Archer. Combined, these two theories allow for a focus on both structure and agency when seeking to understand livelihood adaptations to climate change by communal farmers in Ngundu. The thesis concludes that there are massive constraints inhibiting adaptation measures by Ngundu farmers, but that this should not distract from the deep, often historically-embedded, concerns of Ngundu farmers about climate change and the multiple ways in which they express agency in and through adaptation and coping activities. It also highlights the need for more specifically sociological investigations of climate change and small-scale farmer adaptation, as well as the need for localised studies which are able to identify and analyse the specificities of adaptation.
- Full Text:
- Date Issued: 2020
A model for sustainable operational excellence through knowledge management practices and continuous improvement principles
- Beeken, Wilhelm Frederik Hartmann
- Authors: Beeken, Wilhelm Frederik Hartmann
- Date: 2008
- Subjects: Organizational effectiveness , Knowledge management
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:8699 , http://hdl.handle.net/10948/1061 , Organizational effectiveness , Knowledge management
- Description: Integrating Knowledge Management maturity with associated Continuous Improvement efforts in order to remain competitive, is absent in most Operational Excellence initiatives. Furthermore, the intertwined relationship of Continuous Improvement and work development becomes a crucial focus area for organisations that wish to establish a continuously evolving management system consisting of core values, methodologies and tools with the aim of creating more satisfied customers with less resources. The old industrial paradigm that focused on labour, capital, materials, and energy viewed technology and knowledge as external influences on production. This framework is now being challenged and a new trend is emerging. This trend seeks to transform the old industrial system to that of a knowledge-based which one can lead to innovation and hence economic advantage. Continuous Improvement as a concept has roots in many other fields, including social-technical system design, human relations progress and the discussion surrounding ‘lean manufacturing’. This study will focus on Continuous Improvement as a noun, referring to on the outcome of the process of a stream of emergent innovations. The primary objective of the study is to create a model that will present an organisation with a three-layer knowledge reference process grid, which will align and depict the surrounding business knowledge functions, knowledge-enabling processes and knowledge-manipulating processes aiming for enabling Operational Excellence. This study promotes the theory that the cognitive domain layer, functional domain layer and resources layer of an organisation can be increasingly stimulated by focusing effort through Continuous Improvement routines towards the associated inter-organisational knowledge processes sustaining Operational Excellence. The proposed model is structured to review, compare, evaluate and integrate existing Knowledge Management practices of ii an organisation within the context of clear definitions for important concepts of Knowledge Management. Additionally the model provides an assessment instrument for evaluating the organisation’s Knowledge Management maturity level. The study concerns itself with two concepts towards business value creation which will lead to increased Operational Excellence. Firstly, the maturity of Knowledge Management processes, and secondly the level of the organisation wide process of focused and continuous incremental improvement namely, Continuous Improvement. A case study with PriceWaterhouseCoopers was concluded and an on-line Internet survey was used with a stratified sample from knowledge workers to test the factors from both a Knowledge Management and Continuous Improvement perspective. These factors were verified by means of a hypotheses network, describing in a structured and descriptive way, the importance of Knowledge Management and Continuous Improvement collectively on sustainable Operational Excellence as an integral development of Operational Excellence. With respect to Knowledge Management practices, the hypothesis network proposed at least three domains, which of knowledge generation, knowledge mobilisation and knowledge application as important input to the proposed process grid of knowledge development and associated layer elements. From a Continuous Improvement principles perspective it is apparent that elements from Continuous Improvement routines and Continuous Improvement characteristics are associated with the organisation Continuous Improvement ability. These findings are also a result of the deliberate design of processes, tools, structures and environments with the intent to increase, renew, share or improve the use of knowledge represented in any of the three elements for structural, human and social of intellectual capital. The proposed model combines the framework of the Boyd cycle as it is conceptualized as self-assessment activities, for it becomes possible to use them as basis of a self-assessment with sense making navigational properties across iii the proposed knowledge process grid for the model. The model will facilitate the concept of a three-layer knowledge reference process grid, which represents the main components of the knowledge processes within the cognitive domain layer, functional layer and resources layer of an organisation. The proposed model will deliver a single value that co-exists with the Knowledge Management maturity level and Continuous Improvement readiness index rating attained. Logical relationships to dynamic, evolving and flexible enabling Knowledge Management practices for each layer of the proposed three-layer knowledge reference process grid will be integrated as output of the proposed model. The research has limitations as Knowledge Management practices were measured using a subjective norm scale. It is suggested that a more comprehensive measure of Knowledge Management maturity processes may be needed to represent this construct. The complexity of the proposed model and the number of associated variables included in the results need further confirmation using possible multiple samples and additional measures of Knowledge Management maturity and Continuous Improvement readiness elements. The benefit of the proposed model as a practical Operational Excellence tool is to overcome the perceived gap of implementing Knowledge Management practices and Continuous Improvement principles collectively to deliver and sustain Operational Excellence.
- Full Text:
- Date Issued: 2008
- Authors: Beeken, Wilhelm Frederik Hartmann
- Date: 2008
- Subjects: Organizational effectiveness , Knowledge management
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:8699 , http://hdl.handle.net/10948/1061 , Organizational effectiveness , Knowledge management
- Description: Integrating Knowledge Management maturity with associated Continuous Improvement efforts in order to remain competitive, is absent in most Operational Excellence initiatives. Furthermore, the intertwined relationship of Continuous Improvement and work development becomes a crucial focus area for organisations that wish to establish a continuously evolving management system consisting of core values, methodologies and tools with the aim of creating more satisfied customers with less resources. The old industrial paradigm that focused on labour, capital, materials, and energy viewed technology and knowledge as external influences on production. This framework is now being challenged and a new trend is emerging. This trend seeks to transform the old industrial system to that of a knowledge-based which one can lead to innovation and hence economic advantage. Continuous Improvement as a concept has roots in many other fields, including social-technical system design, human relations progress and the discussion surrounding ‘lean manufacturing’. This study will focus on Continuous Improvement as a noun, referring to on the outcome of the process of a stream of emergent innovations. The primary objective of the study is to create a model that will present an organisation with a three-layer knowledge reference process grid, which will align and depict the surrounding business knowledge functions, knowledge-enabling processes and knowledge-manipulating processes aiming for enabling Operational Excellence. This study promotes the theory that the cognitive domain layer, functional domain layer and resources layer of an organisation can be increasingly stimulated by focusing effort through Continuous Improvement routines towards the associated inter-organisational knowledge processes sustaining Operational Excellence. The proposed model is structured to review, compare, evaluate and integrate existing Knowledge Management practices of ii an organisation within the context of clear definitions for important concepts of Knowledge Management. Additionally the model provides an assessment instrument for evaluating the organisation’s Knowledge Management maturity level. The study concerns itself with two concepts towards business value creation which will lead to increased Operational Excellence. Firstly, the maturity of Knowledge Management processes, and secondly the level of the organisation wide process of focused and continuous incremental improvement namely, Continuous Improvement. A case study with PriceWaterhouseCoopers was concluded and an on-line Internet survey was used with a stratified sample from knowledge workers to test the factors from both a Knowledge Management and Continuous Improvement perspective. These factors were verified by means of a hypotheses network, describing in a structured and descriptive way, the importance of Knowledge Management and Continuous Improvement collectively on sustainable Operational Excellence as an integral development of Operational Excellence. With respect to Knowledge Management practices, the hypothesis network proposed at least three domains, which of knowledge generation, knowledge mobilisation and knowledge application as important input to the proposed process grid of knowledge development and associated layer elements. From a Continuous Improvement principles perspective it is apparent that elements from Continuous Improvement routines and Continuous Improvement characteristics are associated with the organisation Continuous Improvement ability. These findings are also a result of the deliberate design of processes, tools, structures and environments with the intent to increase, renew, share or improve the use of knowledge represented in any of the three elements for structural, human and social of intellectual capital. The proposed model combines the framework of the Boyd cycle as it is conceptualized as self-assessment activities, for it becomes possible to use them as basis of a self-assessment with sense making navigational properties across iii the proposed knowledge process grid for the model. The model will facilitate the concept of a three-layer knowledge reference process grid, which represents the main components of the knowledge processes within the cognitive domain layer, functional layer and resources layer of an organisation. The proposed model will deliver a single value that co-exists with the Knowledge Management maturity level and Continuous Improvement readiness index rating attained. Logical relationships to dynamic, evolving and flexible enabling Knowledge Management practices for each layer of the proposed three-layer knowledge reference process grid will be integrated as output of the proposed model. The research has limitations as Knowledge Management practices were measured using a subjective norm scale. It is suggested that a more comprehensive measure of Knowledge Management maturity processes may be needed to represent this construct. The complexity of the proposed model and the number of associated variables included in the results need further confirmation using possible multiple samples and additional measures of Knowledge Management maturity and Continuous Improvement readiness elements. The benefit of the proposed model as a practical Operational Excellence tool is to overcome the perceived gap of implementing Knowledge Management practices and Continuous Improvement principles collectively to deliver and sustain Operational Excellence.
- Full Text:
- Date Issued: 2008
Separation of rhodium (III) and iridium (IV) using functional polymeric materials
- Authors: Majavu, Avela
- Date: 2014
- Subjects: Rhodium -- Separation , Iridium -- Separation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/6576 , vital:21116
- Description: Poly(vinylbenzylchloride) (PVBC) nanofibers were fabricated by the electrospinning process. The Merrifield micropheres, silica microsparticles and PVBC nanofibers were functionalised with different quaternary diammonium groups derived from ethylenediamine (EDA), tetramethylenediamine (TMDA), hexamethylenediamine (HMDA), 1,8-diaminooctane (OMDA), 1,10-diaminodecane (DMDA) and 1,12-diaminododecane (DDMDA) and investigated for separation of [RhCl5(H2O)]2- and [IrCl6]2-. The sorbent materials were characterised by means of FTIR, XPS, SEM, BET surface area, thermogravimetric analysis and elemental analysis, and characterization results showed that the functionalization of the sorbent materials was successful. Batch equilibrium studies were carried out to assess the efficiency of these different anion exchangers using single metal aqueous solutions. The adsorption isotherms and kinetics of both [RhCl5(H2O)]2- and [IrCl6]2- adsorption onto the sorbent materials are presented. The isothermal batch adsorption studies fitted the Freundlich model indicating heterogeneous surface adsorption. The Freundlich isotherm confirmed multilayer adsorption and the Freundlich constant (kf) displayed the following ascending order for nanofibers (F-QUAT EDA, F-QUAT TMDA, F-QUAT HMDA, F-QUAT OMDA and F-QUAT DMDA), silica microparticles (Si-QUAT EDA, Si-QUAT TMDA, Si-QUAT HMDA, Si-QUAT OMDA and Si-QUAT DMDA) and microspheres (B-QUAT EDA, B-QUAT TMDA, B-QUAT HMDA, B-QUAT OMDA and B-QUAT DMDA) and a decrease in kf for F-QUAT DDMDA, Si-QUAT DDMDA and B-QUAT DDMDA has been observed. The pseudo second-order model was found to be the best fit to describe the adsorption kinetics of both metal ions complexes onto all the sorbent materials. K2 value in pseudo second-order kinetics showed that the rate constant for adsorption of [IrCl6]2- onto nanofibers was larger than for silica microparticles and Merrifield microspheres. Column sorption of [IrCl6]2- and [RhCl5(H2O)]2- was carried out and the loading capacities of [IrCl6]2- were obtained, and they showed dependence on the length of the methylene spacer between the two diammonium centres. [RhCl5(H2O)]2- was not adsorbed by the sorbent materials while [IrCl6]2- was loaded onto the column. The highest iridium loading capacities for all the sorbent materials for the diamines with decylene spacer, and were found to be 32.94 mg/g, 29.35 mg/g, and 27.09 mg/g for F-QUAT DMDA, Si-QUAT DMDA and B-QUAT DMDA respectively. It was also observed on the derivatives of DMDA supported on nanofibers that F-QUAT ethyl loading capacity for iridium (19.89 mg/g) reduced which may be due to the electron-donating nature of the ethyl group and the increase of hydrophobicity whereas F-QUAT benzyl loading capacity (244.64 mg/g) increased dramatically due to increase in the size of the cation which lowers the positive charge density of the quaternary diammonium center. The charge delocalizing ability of the benzyl group resulted in the best interaction of the diammonium group derived from this quaternizing agent, yielding the highest loading capacity for [IrCl6]2-. Reusability was conducted and the results showed that the all the sorbent materials can be used repeatedly without decreasing their adsorption capacity significantly. The neat diammonium salts were also synthesized and interacted with the chorido metal complex anions to form ion-pairs which were then studied for their solubility. The synthesis of the quaternary salts was rather challenging and resulted in some interesting species when impurities of the iodide form of the salts were present in the process of converting them to the iodide form. Some of these include I52+, which was confirmed preliminarily by X-ray structural analysis, potentiometry and cyclic voltammetry. Molecular modeling studies were also conducted to explain the interaction of the chlorido anions with the cationic diammonium centres, and to quantify these interactions by thermodynamic parameters, partial charge calculations, dipole moments and electrostatic potentials, and there was good agreement between theory and experiment. This thesis presents iridium-specific materials that could be applied in solutions of secondary PMGs sources containing rhodium and iridium as well as in feed solutions from ore processing.
- Full Text:
- Date Issued: 2014
- Authors: Majavu, Avela
- Date: 2014
- Subjects: Rhodium -- Separation , Iridium -- Separation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/6576 , vital:21116
- Description: Poly(vinylbenzylchloride) (PVBC) nanofibers were fabricated by the electrospinning process. The Merrifield micropheres, silica microsparticles and PVBC nanofibers were functionalised with different quaternary diammonium groups derived from ethylenediamine (EDA), tetramethylenediamine (TMDA), hexamethylenediamine (HMDA), 1,8-diaminooctane (OMDA), 1,10-diaminodecane (DMDA) and 1,12-diaminododecane (DDMDA) and investigated for separation of [RhCl5(H2O)]2- and [IrCl6]2-. The sorbent materials were characterised by means of FTIR, XPS, SEM, BET surface area, thermogravimetric analysis and elemental analysis, and characterization results showed that the functionalization of the sorbent materials was successful. Batch equilibrium studies were carried out to assess the efficiency of these different anion exchangers using single metal aqueous solutions. The adsorption isotherms and kinetics of both [RhCl5(H2O)]2- and [IrCl6]2- adsorption onto the sorbent materials are presented. The isothermal batch adsorption studies fitted the Freundlich model indicating heterogeneous surface adsorption. The Freundlich isotherm confirmed multilayer adsorption and the Freundlich constant (kf) displayed the following ascending order for nanofibers (F-QUAT EDA, F-QUAT TMDA, F-QUAT HMDA, F-QUAT OMDA and F-QUAT DMDA), silica microparticles (Si-QUAT EDA, Si-QUAT TMDA, Si-QUAT HMDA, Si-QUAT OMDA and Si-QUAT DMDA) and microspheres (B-QUAT EDA, B-QUAT TMDA, B-QUAT HMDA, B-QUAT OMDA and B-QUAT DMDA) and a decrease in kf for F-QUAT DDMDA, Si-QUAT DDMDA and B-QUAT DDMDA has been observed. The pseudo second-order model was found to be the best fit to describe the adsorption kinetics of both metal ions complexes onto all the sorbent materials. K2 value in pseudo second-order kinetics showed that the rate constant for adsorption of [IrCl6]2- onto nanofibers was larger than for silica microparticles and Merrifield microspheres. Column sorption of [IrCl6]2- and [RhCl5(H2O)]2- was carried out and the loading capacities of [IrCl6]2- were obtained, and they showed dependence on the length of the methylene spacer between the two diammonium centres. [RhCl5(H2O)]2- was not adsorbed by the sorbent materials while [IrCl6]2- was loaded onto the column. The highest iridium loading capacities for all the sorbent materials for the diamines with decylene spacer, and were found to be 32.94 mg/g, 29.35 mg/g, and 27.09 mg/g for F-QUAT DMDA, Si-QUAT DMDA and B-QUAT DMDA respectively. It was also observed on the derivatives of DMDA supported on nanofibers that F-QUAT ethyl loading capacity for iridium (19.89 mg/g) reduced which may be due to the electron-donating nature of the ethyl group and the increase of hydrophobicity whereas F-QUAT benzyl loading capacity (244.64 mg/g) increased dramatically due to increase in the size of the cation which lowers the positive charge density of the quaternary diammonium center. The charge delocalizing ability of the benzyl group resulted in the best interaction of the diammonium group derived from this quaternizing agent, yielding the highest loading capacity for [IrCl6]2-. Reusability was conducted and the results showed that the all the sorbent materials can be used repeatedly without decreasing their adsorption capacity significantly. The neat diammonium salts were also synthesized and interacted with the chorido metal complex anions to form ion-pairs which were then studied for their solubility. The synthesis of the quaternary salts was rather challenging and resulted in some interesting species when impurities of the iodide form of the salts were present in the process of converting them to the iodide form. Some of these include I52+, which was confirmed preliminarily by X-ray structural analysis, potentiometry and cyclic voltammetry. Molecular modeling studies were also conducted to explain the interaction of the chlorido anions with the cationic diammonium centres, and to quantify these interactions by thermodynamic parameters, partial charge calculations, dipole moments and electrostatic potentials, and there was good agreement between theory and experiment. This thesis presents iridium-specific materials that could be applied in solutions of secondary PMGs sources containing rhodium and iridium as well as in feed solutions from ore processing.
- Full Text:
- Date Issued: 2014
Indigenous and traditional musics in the school classroom : a re-evaluation of the South African Indigenous African Music (IAM) curriculum
- Authors: McConnachie, Boudina
- Date: 2017
- Subjects: Ethnomusicology , Indigenous people -- Music , Music -- Instruction and study -- Africa , Music -- Instruction and study -- Curricula -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:21182 , http://hdl.handle.net/10962/6806
- Description: Musical ideals set by European standards and values, entrenched through colonial oppression and promoted by the continued veneration of Western culture need to be re-evaluated. Despite the intention of the ANC government, through the Department of Basic Education's Curriculum and Assessment Policy Statement music curricula, to integrate Indigenous Knowledge and musics into the South African classroom, evidence shows that opportunities to do so are not seized. With reference to the proclaimed values of an African sensibility in the model of the South African music education curriculum, the history of its development and the current pedagogical movement towards transformation in the production of knowledge and the inclusion of Indigenous Knowledge (IK), this thesis questions why teachers in government schools in South Africa are not executing the Indigenous African Music (IAM) syllabus in the CAPS FET music curriculum. Taking the history of music education and the development of curriculum models and frameworks into account, it interrogates what strategies could improve the application of the current music curriculum in government schools in South Africa. These questions are addressed in the thesis by way of a discussion of the music curriculum and what its praxis in the classroom reveals about its efficacy, through observations and personal experiences, the observations of teachers and student teachers, a comparison with the experience in Zimbabwe, and an analysis of the music curriculum as it is currently devised and implemented. Straddling three methodological approaches, namely the ethnographic, the autoethnographic and the action research approach this study finds that the CAPS FET music curriculum does provide realistic opportunities to engage with African Indigenous and traditional music. This, however, is dependent upon the training of the teacher, facilities available in the classroom and the prior knowledge of the learner. A fundamental flaw of this curriculum is the approach to practical assessment of Indigenous and traditional African musics and the lack of assessment criteria and practical guidelines. In addition, the findings suggest that the fault regarding implementation of the curriculum lies in the training of students (who become teachers) at tertiary level, where an integrated approach to skills development regarding Indigenous African music is suggested.
- Full Text:
- Date Issued: 2017
- Authors: McConnachie, Boudina
- Date: 2017
- Subjects: Ethnomusicology , Indigenous people -- Music , Music -- Instruction and study -- Africa , Music -- Instruction and study -- Curricula -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:21182 , http://hdl.handle.net/10962/6806
- Description: Musical ideals set by European standards and values, entrenched through colonial oppression and promoted by the continued veneration of Western culture need to be re-evaluated. Despite the intention of the ANC government, through the Department of Basic Education's Curriculum and Assessment Policy Statement music curricula, to integrate Indigenous Knowledge and musics into the South African classroom, evidence shows that opportunities to do so are not seized. With reference to the proclaimed values of an African sensibility in the model of the South African music education curriculum, the history of its development and the current pedagogical movement towards transformation in the production of knowledge and the inclusion of Indigenous Knowledge (IK), this thesis questions why teachers in government schools in South Africa are not executing the Indigenous African Music (IAM) syllabus in the CAPS FET music curriculum. Taking the history of music education and the development of curriculum models and frameworks into account, it interrogates what strategies could improve the application of the current music curriculum in government schools in South Africa. These questions are addressed in the thesis by way of a discussion of the music curriculum and what its praxis in the classroom reveals about its efficacy, through observations and personal experiences, the observations of teachers and student teachers, a comparison with the experience in Zimbabwe, and an analysis of the music curriculum as it is currently devised and implemented. Straddling three methodological approaches, namely the ethnographic, the autoethnographic and the action research approach this study finds that the CAPS FET music curriculum does provide realistic opportunities to engage with African Indigenous and traditional music. This, however, is dependent upon the training of the teacher, facilities available in the classroom and the prior knowledge of the learner. A fundamental flaw of this curriculum is the approach to practical assessment of Indigenous and traditional African musics and the lack of assessment criteria and practical guidelines. In addition, the findings suggest that the fault regarding implementation of the curriculum lies in the training of students (who become teachers) at tertiary level, where an integrated approach to skills development regarding Indigenous African music is suggested.
- Full Text:
- Date Issued: 2017
Biology, population dynamics and management of carpenter (Argyrozona argyrozona) an endemic South African reef fish
- Authors: Brouwer, Stephen Leonard
- Date: 2005
- Subjects: Reef fishes -- South Africa Sparidae -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5241 , http://hdl.handle.net/10962/d1005084
- Description: Carpenter, Argyrozona argyrozona (Valenciennes, 1830), is an endemic South African sparid fish. They form an important component of the commercial linefishery on the South African east coast, where they are the third most important species landed. Recent investigations revealed that the catch per unit effort (cpue) of this species has declined markedly since the early 1900’s. Despite these declines and the importance of this resource, remarkably little biological information on this species exists for providing management advice. This thesis investigates the life history of carpenter, particularly those aspects that are used for management. This includes an investigation into the stock distribution and identification of nursery areas, and an assessment of age, growth, reproduction and movement patterns. Age and growth was assessed using methods based on both otoliths and mark-recapture. Transverse sagittal sections from the Tsitsikamma National Park showed clear opaque and translucent growth increments. Marginal growth zone analysis and mark-recapture of chemically tagged fish (Oxytetracycline) revealed that these were deposited on an annual basis: opaque in summer and translucent in winter. A. argyrozona were found to be long lived (up to 27 years) and slow growing. Within reader (between counts) and between readers average percent error (APE) was 5.3 and 1.8, respectively, showing that readability of carpenter otoliths is high. Comparison between whole and sectioned otoliths showed that the former significantly under-estimated the age of fish older than 10 years (p<0.01). A large proportion (68%) of the individual growth rates derived from mark-recapture data were below those predicted by the otolith based von Bertalanffy growth model (p<0.01). This was attributed to the negative influence of external tags, as hydroids, frequently occurring on the tags of recaptured fish, were observed to cause severe lesions and in some cases, extensive fin damage. This brings into question the use of mark-recapture studies to calculate growth of some species. The effects of sampling design and sample size on age and growth estimation were assessed. The minimum sample size required to accurately estimate growth and mortality, and the effects of using either random or stratified sampling procedures were tested. Decimal and integer ageing both produced similar estimates of von Bertalanffy growth parameters, growth curves, spawner biomass-per-recruit (SB/R) and fishing mortality (F) estimates. Sampling monthly throughout the year and collecting data in a single large sample provided similar growth curves, von Bertalanffy, F and SB/R estimates. The data showed that estimates based on less than 300 random samples were unreliable. However, accurate growth parameter estimates were achievable with less than 200 samples if the sample was stratified with 10 or more samples per 2 cm size class. An investigation into the reproductive biology of A. argyrozona within the Tsitsikamma National Park revealed that they were serial spawning late gonochorists. The size at 50% maturity (L₅₀) was estimated at 292 and 297 mm FL for females and males, respectively. Both monthly gonadosomatic indices and macroscopically determined ovarian stages strongly suggest that A. argyrozona within the Tsitsikamma National Park spawn in the austral summer between November and April. The presence of post-ovulatory follicles (POF's) confirmed the six month spawning season, while monthly proportions of early (0-6 hour old) POF's showed that spawning frequency was highest (once every 1-2 days) from December to March. Although spawning season was more highly correlated to photoperiod (r = 0.859) than temperature (r = -0.161), the daily proportion of spawning fish was strongly correlated (r = 0.93) to ambient temperature over the range 9-22⁰C. Both spawning frequency and season increased with fish length. As a result of the allometric relationship between annual fecundity and fish mass a 3 kg fish was calculated to produce 5 fold more eggs per kilogram of body weight than a fish of 1 kg. In addition to producing more eggs per unit weight each year, larger fish also produce significantly larger eggs. Adult emigration and larval dispersal of A. argyrozona from the Tsitsikamma National Park (TNP), South Africa, were investigated using mark-recapture data and Acoustic Doppler Current Profiler measurements of currents. Tagging data showed that adult carpenter were mainly resident, with a small proportion (7%) leaving the TNP in both easterly and westerly directions. No relationship was found between fish movement patterns and fish size or time-at-liberty. Current patterns suggest that eggs and larvae spawned within the TNP are mainly transported eastwards towards established nursery grounds; the median estimated distance moved was 299 km (range 42-561 km) in 30 days (time to flexion). Given this pattern of ichthyoplankton dispersal together with the fact that adult carpenter within the TNP display a high degree of residency and that they are much more abundant than in adjacent fishing grounds (cpue = 23 times greater), it appears that the TNP protects a viable carpenter spawner population capable of seeding adjacent fishing grounds. Fishery independent biomass surveys and commercial linefish catch returns were used to elucidate the spatial patterns of A. argyrozona distributed along the South African continental shelf. Two distinct areas of abundance were determined, one on the central and the other on the eastern Agulhas Bank. Tagging studies revealed little exchange between them. Two distinct nursery areas were identified. These data suggest that in each area juvenile A. argyrozona settle and move inshore, and then move offshore as they grow. Otolith readability and growth rates varied between regions, with fish from the Eastern Cape having the lowest average percentage error and the slowest growth rates, readability decreased westward. L₅₀ varied between the central and eastern Agulhas Bank as did mass at length. Based on the distribution of carpenter, variability in otolith readability, mass at length, variation in growth and size at maturity, it is concluded that carpenter exist as two separate stocks, one on the central Agulhas Bank and the other on the eastern Agulhas Bank. SB/R, fecundity-per-recruit (Egg/R) and yield-per-recruit (Y/R) models were used to model both South African carpenter stocks. Owing to the allometric relationship between annual fecundity and individual size, Egg/R ratios were between 40 and 74% of SB/R at equivalent F. Egg/R ratios account for allometric increases in fecundity with size/age, and are therefore regarded as more accurate estimates of reproductive potential, and biological reference points for per-recruit analysis should wherever possible be based on this quantum. It is shown that the current length at first capture (lc) (250 mm TL) and F (at M = 0.1) will reduce Egg/R to 6.41% of the pristine value in the Eastern Cape and between 6.06 and 14.15% on the central Agulhas Bank, indicating that both stocks are heavily over exploited. An increase in lc from 250 to 350 mm TL and a 70% reduction in commercial fishing effort is recommended to attain a target reference point of 40% Egg/RF=0. Bag frequency analysis indicates that a reduction in daily bag limit from 10 to 4 fish.person¹.day⁻¹ would effect an equivalent reduction in recreational F. The trawl bycatch of carpenter is only 3% of the reported line catch, consequently restrictions to this fishery are not recommended.
- Full Text:
- Date Issued: 2005
- Authors: Brouwer, Stephen Leonard
- Date: 2005
- Subjects: Reef fishes -- South Africa Sparidae -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5241 , http://hdl.handle.net/10962/d1005084
- Description: Carpenter, Argyrozona argyrozona (Valenciennes, 1830), is an endemic South African sparid fish. They form an important component of the commercial linefishery on the South African east coast, where they are the third most important species landed. Recent investigations revealed that the catch per unit effort (cpue) of this species has declined markedly since the early 1900’s. Despite these declines and the importance of this resource, remarkably little biological information on this species exists for providing management advice. This thesis investigates the life history of carpenter, particularly those aspects that are used for management. This includes an investigation into the stock distribution and identification of nursery areas, and an assessment of age, growth, reproduction and movement patterns. Age and growth was assessed using methods based on both otoliths and mark-recapture. Transverse sagittal sections from the Tsitsikamma National Park showed clear opaque and translucent growth increments. Marginal growth zone analysis and mark-recapture of chemically tagged fish (Oxytetracycline) revealed that these were deposited on an annual basis: opaque in summer and translucent in winter. A. argyrozona were found to be long lived (up to 27 years) and slow growing. Within reader (between counts) and between readers average percent error (APE) was 5.3 and 1.8, respectively, showing that readability of carpenter otoliths is high. Comparison between whole and sectioned otoliths showed that the former significantly under-estimated the age of fish older than 10 years (p<0.01). A large proportion (68%) of the individual growth rates derived from mark-recapture data were below those predicted by the otolith based von Bertalanffy growth model (p<0.01). This was attributed to the negative influence of external tags, as hydroids, frequently occurring on the tags of recaptured fish, were observed to cause severe lesions and in some cases, extensive fin damage. This brings into question the use of mark-recapture studies to calculate growth of some species. The effects of sampling design and sample size on age and growth estimation were assessed. The minimum sample size required to accurately estimate growth and mortality, and the effects of using either random or stratified sampling procedures were tested. Decimal and integer ageing both produced similar estimates of von Bertalanffy growth parameters, growth curves, spawner biomass-per-recruit (SB/R) and fishing mortality (F) estimates. Sampling monthly throughout the year and collecting data in a single large sample provided similar growth curves, von Bertalanffy, F and SB/R estimates. The data showed that estimates based on less than 300 random samples were unreliable. However, accurate growth parameter estimates were achievable with less than 200 samples if the sample was stratified with 10 or more samples per 2 cm size class. An investigation into the reproductive biology of A. argyrozona within the Tsitsikamma National Park revealed that they were serial spawning late gonochorists. The size at 50% maturity (L₅₀) was estimated at 292 and 297 mm FL for females and males, respectively. Both monthly gonadosomatic indices and macroscopically determined ovarian stages strongly suggest that A. argyrozona within the Tsitsikamma National Park spawn in the austral summer between November and April. The presence of post-ovulatory follicles (POF's) confirmed the six month spawning season, while monthly proportions of early (0-6 hour old) POF's showed that spawning frequency was highest (once every 1-2 days) from December to March. Although spawning season was more highly correlated to photoperiod (r = 0.859) than temperature (r = -0.161), the daily proportion of spawning fish was strongly correlated (r = 0.93) to ambient temperature over the range 9-22⁰C. Both spawning frequency and season increased with fish length. As a result of the allometric relationship between annual fecundity and fish mass a 3 kg fish was calculated to produce 5 fold more eggs per kilogram of body weight than a fish of 1 kg. In addition to producing more eggs per unit weight each year, larger fish also produce significantly larger eggs. Adult emigration and larval dispersal of A. argyrozona from the Tsitsikamma National Park (TNP), South Africa, were investigated using mark-recapture data and Acoustic Doppler Current Profiler measurements of currents. Tagging data showed that adult carpenter were mainly resident, with a small proportion (7%) leaving the TNP in both easterly and westerly directions. No relationship was found between fish movement patterns and fish size or time-at-liberty. Current patterns suggest that eggs and larvae spawned within the TNP are mainly transported eastwards towards established nursery grounds; the median estimated distance moved was 299 km (range 42-561 km) in 30 days (time to flexion). Given this pattern of ichthyoplankton dispersal together with the fact that adult carpenter within the TNP display a high degree of residency and that they are much more abundant than in adjacent fishing grounds (cpue = 23 times greater), it appears that the TNP protects a viable carpenter spawner population capable of seeding adjacent fishing grounds. Fishery independent biomass surveys and commercial linefish catch returns were used to elucidate the spatial patterns of A. argyrozona distributed along the South African continental shelf. Two distinct areas of abundance were determined, one on the central and the other on the eastern Agulhas Bank. Tagging studies revealed little exchange between them. Two distinct nursery areas were identified. These data suggest that in each area juvenile A. argyrozona settle and move inshore, and then move offshore as they grow. Otolith readability and growth rates varied between regions, with fish from the Eastern Cape having the lowest average percentage error and the slowest growth rates, readability decreased westward. L₅₀ varied between the central and eastern Agulhas Bank as did mass at length. Based on the distribution of carpenter, variability in otolith readability, mass at length, variation in growth and size at maturity, it is concluded that carpenter exist as two separate stocks, one on the central Agulhas Bank and the other on the eastern Agulhas Bank. SB/R, fecundity-per-recruit (Egg/R) and yield-per-recruit (Y/R) models were used to model both South African carpenter stocks. Owing to the allometric relationship between annual fecundity and individual size, Egg/R ratios were between 40 and 74% of SB/R at equivalent F. Egg/R ratios account for allometric increases in fecundity with size/age, and are therefore regarded as more accurate estimates of reproductive potential, and biological reference points for per-recruit analysis should wherever possible be based on this quantum. It is shown that the current length at first capture (lc) (250 mm TL) and F (at M = 0.1) will reduce Egg/R to 6.41% of the pristine value in the Eastern Cape and between 6.06 and 14.15% on the central Agulhas Bank, indicating that both stocks are heavily over exploited. An increase in lc from 250 to 350 mm TL and a 70% reduction in commercial fishing effort is recommended to attain a target reference point of 40% Egg/RF=0. Bag frequency analysis indicates that a reduction in daily bag limit from 10 to 4 fish.person¹.day⁻¹ would effect an equivalent reduction in recreational F. The trawl bycatch of carpenter is only 3% of the reported line catch, consequently restrictions to this fishery are not recommended.
- Full Text:
- Date Issued: 2005
Nursing strategies to facilitate self-management in persons living with diabetes mellitus type 2
- Authors: O'Brien Coleen Ann
- Date: 2011
- Subjects: Diabetes -- Treatment , Nurses -- South Africa , Diabetes -- Prevention Popular works
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10019 , http://hdl.handle.net/10948/1627 , Diabetes -- Treatment , Nurses -- South Africa , Diabetes -- Prevention Popular works
- Description: The growing pandemic of diabetes mellitus (DM) is continuing to spread around the world with developing countries being most vulnerable. Diabetes mellitus is the direct cause of 5 percent of deaths worldwide at present, with an expected increase of 50percent in the next 10 years. Diabetes mellitus was virtually unknown in Africa at the start of the 20th century but the incidence is expected to increase by 80 percent by 2025. South African estimates indicate that at present there are up to four million people living with DM in South Africa, with an expected rise of 25 percent by 2020. If DM is not adequately controlled, life-threatening complications ensue, resulting in financial, physical and emotional costs both for people living with the condition and for their families. There is also a great financial burden on the state, both directly due to the cost of providing health care and indirectly due to loss of productivity and a reduced tax base. Global initiatives against DM include the Diabetes Strategy for Africa compiled by the International Diabetes Federation and World Health Organization. There are several forms of DM with Type 2 being the most common with an estimated 95% of cases. Optimal glycaemic control is essential for the management of DM, potentially allowing the course of the disease to be slowed or halted. The previous medical model of management of chronic disease has changed to an empowerment approach where the person living with the condition is a partner in the management process. This is particularly true of DM where all aspects of life are affected by the condition. During Phase One of this study, a qualitative, exploratory, descriptive, contextual approach was utilized to explore and describe the experiences of persons living with DM and of diabetes nurse educators who assist them in Nelson Mandela Bay. During Phase Two, a conceptual framework was created and utilized to develop strategies which professional nurses may use in facilitating self-management by persons living with DM. Persons living with DM experience a definite initial experience on diagnosis of DM but gradually gain an acceptance and acknowledgment of their condition. They have definite views on the concept of self-management and experience both positive and negative factors influencing self-management. They also have definite ideas on how professional nurses may assist them in achieving self-management. These findings were confirmed ii by the experiences of the diabetes nurse educators who formed the second group of participants in this study. The ACE approach to self-management of DM consists of an Action Strategy, a Coordination Strategy and an Education Strategy. The ACE approach makes use of grand and functional strategies implemented on the macro (national), meso (provincial) and micro (local) levels to enable the professional nurse to assist persons living with DM to achieve self-management of their condition. Grand strategies need to be implemented on a macro or meso level to enable the professional nurse to function effectively on a micro level. Assisting the patient has to go beyond merely improving knowledge about the condition but has to include individual goal setting as well as problem solving skills and coping strategies as part of a therapeutic relationship between the professional nurse and the person living with DM. The level of personal responsibility achieved by persons living with DM is affected by the memes which they hold regarding their level of health and their ability to address any barriers to self-management which they may experience. Making use of the process of the therapeutic relationship, the professional nurse is able to positively influence the memes held by persons living with DM and assist them in achieving a greater level of personal responsibility. The therapeutic relationship is potentially influenced by all three of the strategies described above. This study provides insight into the experiences of persons living with DM and of the diabetes nurse educators who assist them in Nelson Mandela Bay. Recommendations regarding the implementation of a National Diabetes Policy on a macro level are made, as well as recommendations for nursing practice, education and research. The strategies which were evaluated by an Expert Panel provide a tool for the professional nurse to use while assisting persons living with DM by facilitating the growth of personal responsibility leading to self-management.
- Full Text:
- Date Issued: 2011
- Authors: O'Brien Coleen Ann
- Date: 2011
- Subjects: Diabetes -- Treatment , Nurses -- South Africa , Diabetes -- Prevention Popular works
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10019 , http://hdl.handle.net/10948/1627 , Diabetes -- Treatment , Nurses -- South Africa , Diabetes -- Prevention Popular works
- Description: The growing pandemic of diabetes mellitus (DM) is continuing to spread around the world with developing countries being most vulnerable. Diabetes mellitus is the direct cause of 5 percent of deaths worldwide at present, with an expected increase of 50percent in the next 10 years. Diabetes mellitus was virtually unknown in Africa at the start of the 20th century but the incidence is expected to increase by 80 percent by 2025. South African estimates indicate that at present there are up to four million people living with DM in South Africa, with an expected rise of 25 percent by 2020. If DM is not adequately controlled, life-threatening complications ensue, resulting in financial, physical and emotional costs both for people living with the condition and for their families. There is also a great financial burden on the state, both directly due to the cost of providing health care and indirectly due to loss of productivity and a reduced tax base. Global initiatives against DM include the Diabetes Strategy for Africa compiled by the International Diabetes Federation and World Health Organization. There are several forms of DM with Type 2 being the most common with an estimated 95% of cases. Optimal glycaemic control is essential for the management of DM, potentially allowing the course of the disease to be slowed or halted. The previous medical model of management of chronic disease has changed to an empowerment approach where the person living with the condition is a partner in the management process. This is particularly true of DM where all aspects of life are affected by the condition. During Phase One of this study, a qualitative, exploratory, descriptive, contextual approach was utilized to explore and describe the experiences of persons living with DM and of diabetes nurse educators who assist them in Nelson Mandela Bay. During Phase Two, a conceptual framework was created and utilized to develop strategies which professional nurses may use in facilitating self-management by persons living with DM. Persons living with DM experience a definite initial experience on diagnosis of DM but gradually gain an acceptance and acknowledgment of their condition. They have definite views on the concept of self-management and experience both positive and negative factors influencing self-management. They also have definite ideas on how professional nurses may assist them in achieving self-management. These findings were confirmed ii by the experiences of the diabetes nurse educators who formed the second group of participants in this study. The ACE approach to self-management of DM consists of an Action Strategy, a Coordination Strategy and an Education Strategy. The ACE approach makes use of grand and functional strategies implemented on the macro (national), meso (provincial) and micro (local) levels to enable the professional nurse to assist persons living with DM to achieve self-management of their condition. Grand strategies need to be implemented on a macro or meso level to enable the professional nurse to function effectively on a micro level. Assisting the patient has to go beyond merely improving knowledge about the condition but has to include individual goal setting as well as problem solving skills and coping strategies as part of a therapeutic relationship between the professional nurse and the person living with DM. The level of personal responsibility achieved by persons living with DM is affected by the memes which they hold regarding their level of health and their ability to address any barriers to self-management which they may experience. Making use of the process of the therapeutic relationship, the professional nurse is able to positively influence the memes held by persons living with DM and assist them in achieving a greater level of personal responsibility. The therapeutic relationship is potentially influenced by all three of the strategies described above. This study provides insight into the experiences of persons living with DM and of the diabetes nurse educators who assist them in Nelson Mandela Bay. Recommendations regarding the implementation of a National Diabetes Policy on a macro level are made, as well as recommendations for nursing practice, education and research. The strategies which were evaluated by an Expert Panel provide a tool for the professional nurse to use while assisting persons living with DM by facilitating the growth of personal responsibility leading to self-management.
- Full Text:
- Date Issued: 2011
Latent murderousness: an exploration of the nature and quality of object relations in rage-type murderers
- Authors: Cartwright, Duncan James
- Date: 2000
- Subjects: Murder Murder -- Case studies Murderers -- Psychology Criminal psychology Violence Narcissism Aggressiveness Anger
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2946 , http://hdl.handle.net/10962/d1002455
- Description: In this dissertation I investigate the intrapsychic make-up of rage-type offenders and explore the psychodynamics of the act of murder itself The dissertation begins with a discussion on the defining features of the act of rage-type murder. I then consider the role of personality characteristics and psychopathology in individuals who have committed such offences. With the basic features of the offender and act itself outlined, the following section reviews key areas of debate regarding the psychodynamics of violence and the intrapsychic make-up of the rage-type murderer. I first explore the nature of aggression as debated in psychoanalysis and conclude that the views expressed are often unn,ecessarily polarized regarding the origins of aggression and suggest that the specifics of particular types of aggression require consideration in order to assess their intrapsychic nature. The specifics of rage and violence are discussed with this in mind. In the second chapter of this section I develop a number of intrapsychic dimensions to be used in understanding how different types of violence are constituted. Psychodynamic contributions towards understanding rage-type murder, as a specific form of violence, are then discussed. Following this review, a number of directive ~uestions are formulated regarding (1) the intrapsychic dimension of rage-type murder; (2) the pJ;esence of the borderline personality in such offender~ and its intrapsychic nature; and (3) the_ specific psychodynamics that lie behind what is argued to be a defensive act of murder. A multiple case study approach, using nine imprisoned rage-type offenders, is used to further explore the above issues. Court summary reports, the Thematic Apperception Test and the Psychoanalytic Research Interview comprised the research material, with particular emphasis placed on the interview material. The interview is approached from a psychoanalytic perspective and I develop some theoretical, technical and analytical guidelines to try to broaden Jhe use of psychoanalysis in the research domain. Findings of the research reveal a specific kind of defensive organization that is characterized by a constellation of object relations that I term the 'narcissistic exoskeleton'. I suggest that these findings best fit the description of a particular kind of borderline personality organization typified by apparent 'normality'. Other prominent aspects of the dimensions of violence observed in these cases include: (1) a poor representational capacity; (2) an interactional style characterized by uncontainable projective exchanges between victim and offender; (3) a collusive primary object relationship combined with the absence of an internalized 'third object'; (4) a 'two-faced' superego structure; (5) the internalization of traumatic experience that has become associated with a bad object system; (6) phantasies of restoring ideal good in external objects alongside conscious fantasies of annihilation. Within the context of these factors the intrapsychic events that lead to the act itself are discussed. It is found that a collapse of the 'narcissistic exoskeleton', the intrusion of the bad object system and the unbearable shame that this evokes in the offender are prominent features of what culminates in an act of explosive rage and projective identification. Some of the implications of my research are briefly discussed in the concluding chapter.
- Full Text:
- Date Issued: 2000
- Authors: Cartwright, Duncan James
- Date: 2000
- Subjects: Murder Murder -- Case studies Murderers -- Psychology Criminal psychology Violence Narcissism Aggressiveness Anger
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2946 , http://hdl.handle.net/10962/d1002455
- Description: In this dissertation I investigate the intrapsychic make-up of rage-type offenders and explore the psychodynamics of the act of murder itself The dissertation begins with a discussion on the defining features of the act of rage-type murder. I then consider the role of personality characteristics and psychopathology in individuals who have committed such offences. With the basic features of the offender and act itself outlined, the following section reviews key areas of debate regarding the psychodynamics of violence and the intrapsychic make-up of the rage-type murderer. I first explore the nature of aggression as debated in psychoanalysis and conclude that the views expressed are often unn,ecessarily polarized regarding the origins of aggression and suggest that the specifics of particular types of aggression require consideration in order to assess their intrapsychic nature. The specifics of rage and violence are discussed with this in mind. In the second chapter of this section I develop a number of intrapsychic dimensions to be used in understanding how different types of violence are constituted. Psychodynamic contributions towards understanding rage-type murder, as a specific form of violence, are then discussed. Following this review, a number of directive ~uestions are formulated regarding (1) the intrapsychic dimension of rage-type murder; (2) the pJ;esence of the borderline personality in such offender~ and its intrapsychic nature; and (3) the_ specific psychodynamics that lie behind what is argued to be a defensive act of murder. A multiple case study approach, using nine imprisoned rage-type offenders, is used to further explore the above issues. Court summary reports, the Thematic Apperception Test and the Psychoanalytic Research Interview comprised the research material, with particular emphasis placed on the interview material. The interview is approached from a psychoanalytic perspective and I develop some theoretical, technical and analytical guidelines to try to broaden Jhe use of psychoanalysis in the research domain. Findings of the research reveal a specific kind of defensive organization that is characterized by a constellation of object relations that I term the 'narcissistic exoskeleton'. I suggest that these findings best fit the description of a particular kind of borderline personality organization typified by apparent 'normality'. Other prominent aspects of the dimensions of violence observed in these cases include: (1) a poor representational capacity; (2) an interactional style characterized by uncontainable projective exchanges between victim and offender; (3) a collusive primary object relationship combined with the absence of an internalized 'third object'; (4) a 'two-faced' superego structure; (5) the internalization of traumatic experience that has become associated with a bad object system; (6) phantasies of restoring ideal good in external objects alongside conscious fantasies of annihilation. Within the context of these factors the intrapsychic events that lead to the act itself are discussed. It is found that a collapse of the 'narcissistic exoskeleton', the intrusion of the bad object system and the unbearable shame that this evokes in the offender are prominent features of what culminates in an act of explosive rage and projective identification. Some of the implications of my research are briefly discussed in the concluding chapter.
- Full Text:
- Date Issued: 2000
A critical analysis of organisational justice in the South African financial service industry
- Authors: Mrwebi, Viwe
- Date: 2018
- Subjects: Organizational behavior , Financial services industry -- South Africa -- Management Intrinsic motivation Employee retention Labor turnover
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/33065 , vital:32513
- Description: Organisational justice has captured the interest of scholars in recent years since it is associated with the perceptions and reactions of an individual, to the presence of fairness in an organisation. It thus captures what an individual feel or evaluates to be, morally correct rather than viewing it to be something prescriptive. This study was aimed at investigating the extent of organisational justice on organisational citizenship behaviour, ethical behaviour and employee retention in the South African financial services industry. A hypothetical model and measuring instrument was developed in order to investigate factors that may influence the organisational justice in the financial services industry. Six independent variables (trustworthiness of management, employee engagement, reward system, organisational transparency, two-way communication and organisational climate) were identified as variables that have the potential to influence organisational justice (mediating variable). It was also hypothesised that organisational justice) has the potential to affect the dependent variables (organisational citizenship behaviour, ethical behaviour and employee retention). Furthermore, nine null-hypotheses were developed to test the relationship between independent, mediating and dependent variables. All these variables were clearly defined and operationalised with various items that were obtained from other measuring instruments or self-developed items. A quantitative research approach followed. This study made use of the non-probability sampling technique, specifically convenient and judgemental sampling, as there is no data base of financial services firms available in South Africa. A purposive sample of 800 respondents was drawn from four provinces in South Africa. Factor and regression analyses were used to test the significance of the relationship between the various independent and dependent variables. The mediating variable of organisational justice was viewed by respondents as a two-dimensional construct, namely procedural-interactional justice and distributive justice. Consequently, intrinsic rewards, extrinsic rewards, organisational transparency and organisational climate were identified as independent variables that could have an impact on the procedural-interactional justice to predict organisational citizenship behaviour and reputable employee retention in the financial services industry. No relationships were identified between trustworthiness of management and employee engagement and procedural-interactional justice. The independent variables, trustworthiness of management, extrinsic rewards and organisational climate, could have an impact on distributive justice to predict organisational citizenship behaviour and reputable employee retention in the financial services industry. No relationships were identified between employee engagement, intrinsic rewards, organisational transparency and distributive justice. The findings of this study have contributed to the body of knowledge in the financial services literature in South Africa, by developing a theoretical model and a measuring instrument of organisational justice in the financial services industry. The antecedents of organisational justice in the financial services industry are not well documented in literature and findings of this study could thus contribute towards closing this gap in literature. The findings of this study could also inform policy formulation to assist with the implementation of organisational justice programmes in the financial services industry. This study provided useful and very practical guidelines to organisations in order to ensure the effective strategising and management of OJ that could enhance their local and global competitiveness and long-term survival.
- Full Text:
- Date Issued: 2018
- Authors: Mrwebi, Viwe
- Date: 2018
- Subjects: Organizational behavior , Financial services industry -- South Africa -- Management Intrinsic motivation Employee retention Labor turnover
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/33065 , vital:32513
- Description: Organisational justice has captured the interest of scholars in recent years since it is associated with the perceptions and reactions of an individual, to the presence of fairness in an organisation. It thus captures what an individual feel or evaluates to be, morally correct rather than viewing it to be something prescriptive. This study was aimed at investigating the extent of organisational justice on organisational citizenship behaviour, ethical behaviour and employee retention in the South African financial services industry. A hypothetical model and measuring instrument was developed in order to investigate factors that may influence the organisational justice in the financial services industry. Six independent variables (trustworthiness of management, employee engagement, reward system, organisational transparency, two-way communication and organisational climate) were identified as variables that have the potential to influence organisational justice (mediating variable). It was also hypothesised that organisational justice) has the potential to affect the dependent variables (organisational citizenship behaviour, ethical behaviour and employee retention). Furthermore, nine null-hypotheses were developed to test the relationship between independent, mediating and dependent variables. All these variables were clearly defined and operationalised with various items that were obtained from other measuring instruments or self-developed items. A quantitative research approach followed. This study made use of the non-probability sampling technique, specifically convenient and judgemental sampling, as there is no data base of financial services firms available in South Africa. A purposive sample of 800 respondents was drawn from four provinces in South Africa. Factor and regression analyses were used to test the significance of the relationship between the various independent and dependent variables. The mediating variable of organisational justice was viewed by respondents as a two-dimensional construct, namely procedural-interactional justice and distributive justice. Consequently, intrinsic rewards, extrinsic rewards, organisational transparency and organisational climate were identified as independent variables that could have an impact on the procedural-interactional justice to predict organisational citizenship behaviour and reputable employee retention in the financial services industry. No relationships were identified between trustworthiness of management and employee engagement and procedural-interactional justice. The independent variables, trustworthiness of management, extrinsic rewards and organisational climate, could have an impact on distributive justice to predict organisational citizenship behaviour and reputable employee retention in the financial services industry. No relationships were identified between employee engagement, intrinsic rewards, organisational transparency and distributive justice. The findings of this study have contributed to the body of knowledge in the financial services literature in South Africa, by developing a theoretical model and a measuring instrument of organisational justice in the financial services industry. The antecedents of organisational justice in the financial services industry are not well documented in literature and findings of this study could thus contribute towards closing this gap in literature. The findings of this study could also inform policy formulation to assist with the implementation of organisational justice programmes in the financial services industry. This study provided useful and very practical guidelines to organisations in order to ensure the effective strategising and management of OJ that could enhance their local and global competitiveness and long-term survival.
- Full Text:
- Date Issued: 2018
Teachers' perceptions on the effects of frequent change in curriculum on effective teaching in junior secondary schools at Libode Education District, Eastern Cape
- Ngibe, Nondwe Cynthia Phelokazi
- Authors: Ngibe, Nondwe Cynthia Phelokazi
- Date: 2016
- Subjects: Curriculum change -- South Africa -- Eastern Cape Educational change Education -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/5587 , vital:29349
- Description: Worldwide educational change has been a topic of discussion. South Africa is among the countries having issues with the implementation of a new curriculum and its impact on effective teaching and learning in junior secondary schools. The country (South Africa) experienced frequent changes in education curriculum. The new curriculum was seen as the means to address poor state of education. It is common knowledge that teachers were and are presently still confused and stressed being unsure on how to apply some techniques to meet the requirements of the new curriculum. That led to underperformance of learners in their work at school. Hence, this study was conducted to explore the perceptions of teachers in South Africa regarding the effects that frequent changes in curriculum has on the effective teaching and learning in junior secondary schools. The change in curriculum is frequent in the sense that, from 1997 to 2016, the curriculum in South Africa was revised four times: Curriculum 2005 (C2005) in 1997, Revised National Curriculum Statement (RNCS) in 2002, National Curriculum Statement (NCS) in 2007 as well as Curriculum and Assessment Policy Statement (CAPS) in 2012. The study does not leave behind some literatures on concept of education, teaching and learning in junior secondary schools, curriculum in South Africa, an overview of curriculum policy in South Africa, curriculum changes to mention a few. Qualitative research methodology was used by the researcher so as interview participants (teachers) in their workplace. The case study was chosen as the design, whereby two junior secondary schools from the population of schools in Libode district were purposely sampled. Data was collected from teachers in these schools, that is, six teachers from each school. Four teachers from each phase were targeted, that is, (four from foundation phase, four from intermediate phase and four from senior phase). Semi-structured interviews were used as the instrument to collect information from the participants. From the study, the researcher found confusion and frustration due to the frequent changes in curriculum; negative influence on effective teaching and learning, by the fact that teachers ultimately do not know what to do to meet the requirements of the curriculum; and not much continuity or links between phases in as far as content and subjects are concerned. The study recommended the appointment of professional facilitators, revisiting of the language policy in GET band (with focus in LOLT in foundation phase), encouraging continuity across phases, actively involvement of teachers in formulating or drafting of any policy that will affect curriculum since they are the implementers of curriculum. The study established that frequent change in curriculum had negative effects on teaching and in junior secondary schools. This is the perception of the majority of participants. As far as literature regarding teachers is concerned, changing curriculum without changing teachers’ understanding and attitude has negative impact on learning especially in South Africa, with special focus on rural schools such as those of Libode district in the Eastern Cape Province.
- Full Text:
- Date Issued: 2016
- Authors: Ngibe, Nondwe Cynthia Phelokazi
- Date: 2016
- Subjects: Curriculum change -- South Africa -- Eastern Cape Educational change Education -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/5587 , vital:29349
- Description: Worldwide educational change has been a topic of discussion. South Africa is among the countries having issues with the implementation of a new curriculum and its impact on effective teaching and learning in junior secondary schools. The country (South Africa) experienced frequent changes in education curriculum. The new curriculum was seen as the means to address poor state of education. It is common knowledge that teachers were and are presently still confused and stressed being unsure on how to apply some techniques to meet the requirements of the new curriculum. That led to underperformance of learners in their work at school. Hence, this study was conducted to explore the perceptions of teachers in South Africa regarding the effects that frequent changes in curriculum has on the effective teaching and learning in junior secondary schools. The change in curriculum is frequent in the sense that, from 1997 to 2016, the curriculum in South Africa was revised four times: Curriculum 2005 (C2005) in 1997, Revised National Curriculum Statement (RNCS) in 2002, National Curriculum Statement (NCS) in 2007 as well as Curriculum and Assessment Policy Statement (CAPS) in 2012. The study does not leave behind some literatures on concept of education, teaching and learning in junior secondary schools, curriculum in South Africa, an overview of curriculum policy in South Africa, curriculum changes to mention a few. Qualitative research methodology was used by the researcher so as interview participants (teachers) in their workplace. The case study was chosen as the design, whereby two junior secondary schools from the population of schools in Libode district were purposely sampled. Data was collected from teachers in these schools, that is, six teachers from each school. Four teachers from each phase were targeted, that is, (four from foundation phase, four from intermediate phase and four from senior phase). Semi-structured interviews were used as the instrument to collect information from the participants. From the study, the researcher found confusion and frustration due to the frequent changes in curriculum; negative influence on effective teaching and learning, by the fact that teachers ultimately do not know what to do to meet the requirements of the curriculum; and not much continuity or links between phases in as far as content and subjects are concerned. The study recommended the appointment of professional facilitators, revisiting of the language policy in GET band (with focus in LOLT in foundation phase), encouraging continuity across phases, actively involvement of teachers in formulating or drafting of any policy that will affect curriculum since they are the implementers of curriculum. The study established that frequent change in curriculum had negative effects on teaching and in junior secondary schools. This is the perception of the majority of participants. As far as literature regarding teachers is concerned, changing curriculum without changing teachers’ understanding and attitude has negative impact on learning especially in South Africa, with special focus on rural schools such as those of Libode district in the Eastern Cape Province.
- Full Text:
- Date Issued: 2016
Assessing the optimal size and composition of public debt in Zimbabwe
- Authors: Mupunga, Nebson
- Date: 2014
- Subjects: Debts, Public -- Management , Debts, Public -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: http://hdl.handle.net/10948/8977 , vital:26448
- Description: This study provides an analysis of public debt dynamics with a view to assess the optimal size and composition of public debt in Zimbabwe that is consistent with maintaining public debt at sustainable levels. The analysis was performed by applying public debt data for Zimbabwe over the period 1980 to 2012. Robustness checks were conducted, using data for selected low income countries in the sub-Saharan Africa. The study was motivated by the public debt management concerns caused by the 2008/09 global financial crisis and the European sovereign debt crisis as well as the external public debt overhang experienced by Zimbabwe since the year 2000. The findings of the study complement existing research findings and information on public debt management of the International Monetary Fund (IMF) and other researchers. The major contribution of this thesis is the determination of optimal public debt thresholds for Zimbabwe. The optimal public debt thresholds were estimated from a joint analysis of the macroeconomic variables that affect public debt and the reaction of fiscal policy to changes in debt. The classical linear regression and Bayesian Vector Auto Regression (BVAR) models were applied to examine the drivers of debt accumulation and to assess the sensitivity of debt to macroeconomic shocks. The information from the drivers of public debt accumulation, together with the fiscal response mechanism was used to calibrate the long-run stable (optimal) public debt target. The optimal public debt threshold was also determined by assessing the link between public debt and economic growth. This assessment was carried out to establish the tipping point beyond which public debt adversely affects growth. Such a tipping point provides valuable information on the optimal size of public debt. The study also applied simulation approaches to determine the optimal composition of public debt. The results show that public debt dynamics in Zimbabwe largely comprised extensive stock flow adjustments emanating from extra budgetary expenditures to meet social and political related needs. The results of the assessment on the sensitivity of public debt to macroeconomic shocks show that Zimbabwe‟s public debt has been more vulnerable to economic growth, exchange rate and interest rate shocks. The significant influence of these variables highlights the role of automatic debt dynamics in public debt management. The results from the fiscal reaction function show that government has been responding positively to increases in public debt. This analysis also shows that government‟s policies are a-cyclical; as explained by the negative and insignificant response of the primary balance to the output gap. The dynamic stochastic simulation analysis suggests that Zimbabwe‟s public debt could follow an array of potential paths depending on the policy stance implemented by government. The simulated risk to public debt dynamics is larger, with an upper bound public debt to GDP ratio of 100 per cent and a lower bound public debt ratio of 32 per cent. The simulated lower bound provides a measure of a natural debt limit, which the government could adopt without fearing the risk of default. The results suggest that the main risks to public debt sustainability lie in growth shocks, whose volatility have been high for the period under study. The results from the analysis of growth and debt confirm the existence of an optimal growth maximising public debt ratio depicted by an inverted U-shaped relationship between public debt and economic growth. The optimal size of public debt was found to be at public debt levels of between 45-50 per cent of GDP. This means that higher public debt ratios have been associated with lower economic growth rates at debt levels above 50 per cent of GDP. The results are consistent with empirical findings for low income countries which suggest the existence of a debt laffer-curve. The results from an analysis of an optimal composition of public debt show a trade-off between a debt composition with more external concessional debt and one with more domestic debt. While a composition with more concessional borrowing was found to be desirable from a cost perspective, it proved to be less desirable from a risk perspective after taking into consideration stock flow adjustments due to changes in cross exchange rates. The findings of the study point to a need for the Zimbabwean government to swiftly respond to increases in public debt to control the swings in debt dynamics caused by macroeconomic shocks. The inverted U-shaped relationship between debt and growth suggests that government borrowing must be done in a way that simultaneously entrenches debt sustainability and ensures sustained economic growth rates in the medium to long-term. The study also highlights the need for counter-cyclical macroeconomic policies to avoid explosive debt dynamics emanating from frequent changes in the business cycle, and to minimise the interest/growth rate differential to ensure sustainable public debt dynamics. There is also a need for authorities to ensure a true balance between external and domestic borrowing to minimise the volatility in debt service costs caused by macroeconomic shocks. Generally, the findings from this study can assist in informing the policy agenda to address the imperatives of debt resolution, fiscal consolidation and economic growth acceleration.
- Full Text:
- Date Issued: 2014
- Authors: Mupunga, Nebson
- Date: 2014
- Subjects: Debts, Public -- Management , Debts, Public -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: http://hdl.handle.net/10948/8977 , vital:26448
- Description: This study provides an analysis of public debt dynamics with a view to assess the optimal size and composition of public debt in Zimbabwe that is consistent with maintaining public debt at sustainable levels. The analysis was performed by applying public debt data for Zimbabwe over the period 1980 to 2012. Robustness checks were conducted, using data for selected low income countries in the sub-Saharan Africa. The study was motivated by the public debt management concerns caused by the 2008/09 global financial crisis and the European sovereign debt crisis as well as the external public debt overhang experienced by Zimbabwe since the year 2000. The findings of the study complement existing research findings and information on public debt management of the International Monetary Fund (IMF) and other researchers. The major contribution of this thesis is the determination of optimal public debt thresholds for Zimbabwe. The optimal public debt thresholds were estimated from a joint analysis of the macroeconomic variables that affect public debt and the reaction of fiscal policy to changes in debt. The classical linear regression and Bayesian Vector Auto Regression (BVAR) models were applied to examine the drivers of debt accumulation and to assess the sensitivity of debt to macroeconomic shocks. The information from the drivers of public debt accumulation, together with the fiscal response mechanism was used to calibrate the long-run stable (optimal) public debt target. The optimal public debt threshold was also determined by assessing the link between public debt and economic growth. This assessment was carried out to establish the tipping point beyond which public debt adversely affects growth. Such a tipping point provides valuable information on the optimal size of public debt. The study also applied simulation approaches to determine the optimal composition of public debt. The results show that public debt dynamics in Zimbabwe largely comprised extensive stock flow adjustments emanating from extra budgetary expenditures to meet social and political related needs. The results of the assessment on the sensitivity of public debt to macroeconomic shocks show that Zimbabwe‟s public debt has been more vulnerable to economic growth, exchange rate and interest rate shocks. The significant influence of these variables highlights the role of automatic debt dynamics in public debt management. The results from the fiscal reaction function show that government has been responding positively to increases in public debt. This analysis also shows that government‟s policies are a-cyclical; as explained by the negative and insignificant response of the primary balance to the output gap. The dynamic stochastic simulation analysis suggests that Zimbabwe‟s public debt could follow an array of potential paths depending on the policy stance implemented by government. The simulated risk to public debt dynamics is larger, with an upper bound public debt to GDP ratio of 100 per cent and a lower bound public debt ratio of 32 per cent. The simulated lower bound provides a measure of a natural debt limit, which the government could adopt without fearing the risk of default. The results suggest that the main risks to public debt sustainability lie in growth shocks, whose volatility have been high for the period under study. The results from the analysis of growth and debt confirm the existence of an optimal growth maximising public debt ratio depicted by an inverted U-shaped relationship between public debt and economic growth. The optimal size of public debt was found to be at public debt levels of between 45-50 per cent of GDP. This means that higher public debt ratios have been associated with lower economic growth rates at debt levels above 50 per cent of GDP. The results are consistent with empirical findings for low income countries which suggest the existence of a debt laffer-curve. The results from an analysis of an optimal composition of public debt show a trade-off between a debt composition with more external concessional debt and one with more domestic debt. While a composition with more concessional borrowing was found to be desirable from a cost perspective, it proved to be less desirable from a risk perspective after taking into consideration stock flow adjustments due to changes in cross exchange rates. The findings of the study point to a need for the Zimbabwean government to swiftly respond to increases in public debt to control the swings in debt dynamics caused by macroeconomic shocks. The inverted U-shaped relationship between debt and growth suggests that government borrowing must be done in a way that simultaneously entrenches debt sustainability and ensures sustained economic growth rates in the medium to long-term. The study also highlights the need for counter-cyclical macroeconomic policies to avoid explosive debt dynamics emanating from frequent changes in the business cycle, and to minimise the interest/growth rate differential to ensure sustainable public debt dynamics. There is also a need for authorities to ensure a true balance between external and domestic borrowing to minimise the volatility in debt service costs caused by macroeconomic shocks. Generally, the findings from this study can assist in informing the policy agenda to address the imperatives of debt resolution, fiscal consolidation and economic growth acceleration.
- Full Text:
- Date Issued: 2014
Integrated Algae Pond Systems for the Treatment of Municipal Wastewater
- Authors: Mambo, Mutsa Prudence
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5960 , http://hdl.handle.net/10962/d1021258
- Description: Integrated algae pond systems are a derivation of the Oswald designed advanced integrated wastewater ponding system, and combine the use of anaerobic and aerobic bioprocesses to effect wastewater treatment. Integrated algae pond system technology was introduced to South Africa in 1996 and a pilot plant was designed and commissioned at the Belmont Valley wastewater treatment works in Grahamstown. Previous studies showed that this system delivered a final effluent superior to most pond systems deployed in South Africa but that it was unable to meet the general standard for nutrient removal and effluent discharge. This study was initiated to re-appraise integrated algae pond systems and to assess the potential of the technology as an effective municipal sewage treatment system. And more...
- Full Text:
- Date Issued: 2016
- Authors: Mambo, Mutsa Prudence
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5960 , http://hdl.handle.net/10962/d1021258
- Description: Integrated algae pond systems are a derivation of the Oswald designed advanced integrated wastewater ponding system, and combine the use of anaerobic and aerobic bioprocesses to effect wastewater treatment. Integrated algae pond system technology was introduced to South Africa in 1996 and a pilot plant was designed and commissioned at the Belmont Valley wastewater treatment works in Grahamstown. Previous studies showed that this system delivered a final effluent superior to most pond systems deployed in South Africa but that it was unable to meet the general standard for nutrient removal and effluent discharge. This study was initiated to re-appraise integrated algae pond systems and to assess the potential of the technology as an effective municipal sewage treatment system. And more...
- Full Text:
- Date Issued: 2016
Contextual factors influencing the use of learner-centred approaches in the teaching of home economics : a case of two universities in Zimbabwe
- Authors: Motsi, Emily
- Date: 2017
- Subjects: Home economics -- Study and teaching (Higher) -- Zimbabwe Student-centered learning -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/8463 , vital:32834
- Description: This study examined contextual factors influencing the use of learner-centred approaches in the teaching of Home Economics in two universities in Zimbabwe. The sample consisted of eight students and four lecturers who were purposively sampled. The study was anchored in the interpretivist paradigm and it adopted a qualitative approach and case-study design. Data collection instruments consisted of structured in-depth interviews, observations and documents. Interviews were conducted with students and lecturers at their respective universities with observations and document analysis inter-spaced in between. Data analysis consisted of a thematic approach where common themes were identified in participants’ responses and analysed and discussed accordingly, with data from observed and documented analysis being used to buttress/refute observations made from the interviews. A number of findings emanated from the study. Students had varied conceptions of learner-centred approaches. Some viewed learner-centred approaches as methods of teaching that were participatory, while others viewed them as learning situations in which learners were actively engaged and developed specific capabilities such as problem-solving. Lecturers conceptualised learner-centred approaches as methods that led to active learner participation with the lecturer playing more of a facilitative role. The study revealed that contextual factors such as time available in each course, flexibility of content, the use of teaching methods characterised by active learner participation, the use of constructive and interactive learning activities, had facilitative as well as inhibiting influences on the use of learner-centred approaches. Social factors such as cooperativeness within the peer group, lecturer availability for consultations, technical staff support as well as structural factors such as the availability of textbooks and e-resources, provision of materials and tools, and access to the internet had a facilitative influence on use of learner-centred approaches. The main inhibitive structural factors were the absence of purpose-built facilities and limited space that caused overcrowding. University administration support for integration of learner-centred approaches was fairly evident in the two universities. To sustain the use of learner-centred approaches, lecturers required support through professional development. The study recommended that universities have well-articulated commitments to use learner-centred approaches through a Teaching and Learning Policy. Home Economics course designers should consider contextual factors in course design and course delivery to ensure effective implementation of learner-centred approaches in the teaching of the subject. Seminars and workshops should be organised by the University Teaching and Learning Centres to enhance the teacher educators’ knowledge on interactive teaching methodologies and strategies for creating student-centred learning environments.
- Full Text:
- Date Issued: 2017
- Authors: Motsi, Emily
- Date: 2017
- Subjects: Home economics -- Study and teaching (Higher) -- Zimbabwe Student-centered learning -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/8463 , vital:32834
- Description: This study examined contextual factors influencing the use of learner-centred approaches in the teaching of Home Economics in two universities in Zimbabwe. The sample consisted of eight students and four lecturers who were purposively sampled. The study was anchored in the interpretivist paradigm and it adopted a qualitative approach and case-study design. Data collection instruments consisted of structured in-depth interviews, observations and documents. Interviews were conducted with students and lecturers at their respective universities with observations and document analysis inter-spaced in between. Data analysis consisted of a thematic approach where common themes were identified in participants’ responses and analysed and discussed accordingly, with data from observed and documented analysis being used to buttress/refute observations made from the interviews. A number of findings emanated from the study. Students had varied conceptions of learner-centred approaches. Some viewed learner-centred approaches as methods of teaching that were participatory, while others viewed them as learning situations in which learners were actively engaged and developed specific capabilities such as problem-solving. Lecturers conceptualised learner-centred approaches as methods that led to active learner participation with the lecturer playing more of a facilitative role. The study revealed that contextual factors such as time available in each course, flexibility of content, the use of teaching methods characterised by active learner participation, the use of constructive and interactive learning activities, had facilitative as well as inhibiting influences on the use of learner-centred approaches. Social factors such as cooperativeness within the peer group, lecturer availability for consultations, technical staff support as well as structural factors such as the availability of textbooks and e-resources, provision of materials and tools, and access to the internet had a facilitative influence on use of learner-centred approaches. The main inhibitive structural factors were the absence of purpose-built facilities and limited space that caused overcrowding. University administration support for integration of learner-centred approaches was fairly evident in the two universities. To sustain the use of learner-centred approaches, lecturers required support through professional development. The study recommended that universities have well-articulated commitments to use learner-centred approaches through a Teaching and Learning Policy. Home Economics course designers should consider contextual factors in course design and course delivery to ensure effective implementation of learner-centred approaches in the teaching of the subject. Seminars and workshops should be organised by the University Teaching and Learning Centres to enhance the teacher educators’ knowledge on interactive teaching methodologies and strategies for creating student-centred learning environments.
- Full Text:
- Date Issued: 2017
The role of the press in political conflicts in Kenya : a case study of the performance of the nation and the East African Standard Newspapers
- Authors: Nyambuga, Charles Ongadi
- Date: 2011
- Subjects: Press and politics -- Kenya , Government and the press -- Kenya , Mass media -- Political aspects , Kenya -- Politics and government
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:16135 , http://hdl.handle.net/10948/1449 , Press and politics -- Kenya , Government and the press -- Kenya , Mass media -- Political aspects , Kenya -- Politics and government
- Description: This study focuses on the role of the press in violent political conflicts in Kenya in the period that preceded the 2005 referendum on the draft constitution. Based on media reports, six major thematic areas of concern emerged during constitution making. These were: land tenure, devolution of power, the executive, the legislature, the Bill of Rights, and the provincial administration. These sections of the draft constitution caused a remarkable divergence of opinion. The citizens either supported or opposed the draft constitution on the basis of how the draft had treated those sections in the draft constitution. Besides the major thematic areas, newspapers regularly focused and reported on ethnicity, violence, political leaders‟ utterances, the process of constitution making, and political conflicts. Three main objectives guided the study. The first objective focused on the relationship between media content and different levels of political conflict. The influence of media content and how these may have led to high political conflict, medium political conflict, low political conflict and no political conflict, are tested in this study. The second objective highlighted the kind of coverage that the draft constitution got during the period that preceded the referendum in November, 2005. This objective facilitated interrogation of media content and whether media content focused on aspects of the draft constitution such as land ownership, the executive, devolution, the legislature and religion, as highlighted in the draft constitution of Kenya 2005. The third objective examined the thematic emphasis that the media undertook in the period that preceded the referendum. The themes that were dominant in the period before the referendum could have impacted on readers' perceptions of the critical issues that could have informed the voters' decisions. Three primary questions were addressed in the study: Firstly, was there a link between media content and different levels of political conflict in weak democracies such as Kenya? Secondly, did media content influence ethnicity and did it encourage ethnic conflict in diverse societies? Finally, what were the key thematic areas of coverage by the press, and how were they used during the referendum? In order to study these research objectives, I used a combination of theories to enhance understanding of the interplay between media content and audience in the society. The theories are: agenda setting, two-step flow, priming, framing, and the public sphere. The study adopts a triangulation convergence design in mixed- methods research that involves both qualitative and quantitative methods. A structured questionnaire and content analysis were used to seek responses to the research questions of the study and to meet the stated objectives. The research revealed that the two newspapers under investigation, namely the East African Standard and the Nation, provided more coverage to issues that were not central to the content of the draft constitution, such as political leaders' utterances, violence, ethnicity, and the process of constitution making. This showed that the newspapers tended to sensationalise issues instead of providing objective coverage of political matters. These newspapers used their opinion pages to educate their readers on how the referendum was turning violent. The theme of political leaders' utterances is closely linked to that of violence. This suggests that the violence was influenced by some of the leaders' statements. These utterances, and more so those that touched on ethnicity, could therefore have been a potential cause of the ensuing political conflicts during the 2005 referendum on the draft constitution. The findings reveal that newspaper editors tended to focus on political conflict at the expense of the actual content of the draft constitution. This would have provided insight and knowledge on the document and avoided sensational reporting, which could have contributed to violent political conflicts during the period that preceded the referendum on the draft constitution of Kenya.
- Full Text:
- Date Issued: 2011
- Authors: Nyambuga, Charles Ongadi
- Date: 2011
- Subjects: Press and politics -- Kenya , Government and the press -- Kenya , Mass media -- Political aspects , Kenya -- Politics and government
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:16135 , http://hdl.handle.net/10948/1449 , Press and politics -- Kenya , Government and the press -- Kenya , Mass media -- Political aspects , Kenya -- Politics and government
- Description: This study focuses on the role of the press in violent political conflicts in Kenya in the period that preceded the 2005 referendum on the draft constitution. Based on media reports, six major thematic areas of concern emerged during constitution making. These were: land tenure, devolution of power, the executive, the legislature, the Bill of Rights, and the provincial administration. These sections of the draft constitution caused a remarkable divergence of opinion. The citizens either supported or opposed the draft constitution on the basis of how the draft had treated those sections in the draft constitution. Besides the major thematic areas, newspapers regularly focused and reported on ethnicity, violence, political leaders‟ utterances, the process of constitution making, and political conflicts. Three main objectives guided the study. The first objective focused on the relationship between media content and different levels of political conflict. The influence of media content and how these may have led to high political conflict, medium political conflict, low political conflict and no political conflict, are tested in this study. The second objective highlighted the kind of coverage that the draft constitution got during the period that preceded the referendum in November, 2005. This objective facilitated interrogation of media content and whether media content focused on aspects of the draft constitution such as land ownership, the executive, devolution, the legislature and religion, as highlighted in the draft constitution of Kenya 2005. The third objective examined the thematic emphasis that the media undertook in the period that preceded the referendum. The themes that were dominant in the period before the referendum could have impacted on readers' perceptions of the critical issues that could have informed the voters' decisions. Three primary questions were addressed in the study: Firstly, was there a link between media content and different levels of political conflict in weak democracies such as Kenya? Secondly, did media content influence ethnicity and did it encourage ethnic conflict in diverse societies? Finally, what were the key thematic areas of coverage by the press, and how were they used during the referendum? In order to study these research objectives, I used a combination of theories to enhance understanding of the interplay between media content and audience in the society. The theories are: agenda setting, two-step flow, priming, framing, and the public sphere. The study adopts a triangulation convergence design in mixed- methods research that involves both qualitative and quantitative methods. A structured questionnaire and content analysis were used to seek responses to the research questions of the study and to meet the stated objectives. The research revealed that the two newspapers under investigation, namely the East African Standard and the Nation, provided more coverage to issues that were not central to the content of the draft constitution, such as political leaders' utterances, violence, ethnicity, and the process of constitution making. This showed that the newspapers tended to sensationalise issues instead of providing objective coverage of political matters. These newspapers used their opinion pages to educate their readers on how the referendum was turning violent. The theme of political leaders' utterances is closely linked to that of violence. This suggests that the violence was influenced by some of the leaders' statements. These utterances, and more so those that touched on ethnicity, could therefore have been a potential cause of the ensuing political conflicts during the 2005 referendum on the draft constitution. The findings reveal that newspaper editors tended to focus on political conflict at the expense of the actual content of the draft constitution. This would have provided insight and knowledge on the document and avoided sensational reporting, which could have contributed to violent political conflicts during the period that preceded the referendum on the draft constitution of Kenya.
- Full Text:
- Date Issued: 2011
Aquatic invasions of the Nseleni River system: causes, consequences and control
- Authors: Jones, Roy William
- Date: 2015
- Subjects: Gastropoda -- South Africa , Introduced snails -- South Africa , Introduced mollusks -- South Africa , Loricariidae , Introduced fishes -- South Africa , Water hyacinth , Alien plants -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5928 , http://hdl.handle.net/10962/d1017806
- Description: Globalization has seen an unprecedented dispersal of exotic and alien species worldwide resulting in worldwide homogenization and sometimes extinction of indigenous or endemic taxa. When an exotic species becomes established in a new habitat the invasive organisms are capable of having an impact on indigenous community dynamics and the overall structure and function of ecosystems. Furthermore, the impact of invasion is determined by the geographical range, abundance and the per-capita or per-biomass effect of the invader. However, the success of the introduced organisms is reliant on their ability to acclimate to the physiochemical conditions of the newly invaded environment.Freshwater ecosystems are especially vulnerable to invasions because there are numerous potential routes of introduction including intentional pathways such as stocking, and unintentional pathways such as the release of ballast water and aquarium releases. Efforts to limit the introduction of invasive species or to manage established exotic populations are often hindered by insufficient understanding of the natural history of problematic species. Relatively little is known regarding the physiological tolerances of many taxa. Knowledge about specific species ecophysiological constraints allows for the prediction of future patterns of invasion more accurately, including where an introduced organism would probably survive, thrive and disperse. Furthermore, data on the physiological tolerances of an introduced exotic organism may provide data necessary for effective management and control. This studyinvestigated three invasive species in the Nseleni River system in a protected area in KwaZulu-Natal. The species studied were, Tarebia granifera (Quilted melania – Lamarck, 1822), Pterygoplichthys disjunctivus (Suckermouth armoured catfish - Weber, 1991) and Eichhornia crassipes (water hyacinth – (Martius) Solms-Laubach,). The Nseleni River flows into Lake Nsezi which is responsible for providing potable water to the surrounding towns and industry, as well as the surrounding rural communities. The Enseleni Nature reserve has become the centre for biodiversity dispersal in the immediate area, due to the change in landscape surrounding the protected area.An important step in developing alien invasive species management strategies in protected areas is determining their extent and invasive traits. Tarebia granifera is a prosobranch gastropod originally from South-East Asia that has become invasive in several countries around the world including South Africa. Snail populations were sampled at nine sites throughout the Nseleni/Mposa river system every six weeks over a twelve month period. The snail was abundant throughout the system, especially in shallow waters of less than 1m in depth.The first positive identification the loricariid catfish Pterygoplichthys disjunctivus for the Nseleni River was in 2006. The original introduction is believed to have been via the aquarium trade. The aim of the study was to assess the usefulness of the unified framework with regard to management of fish invasions by assessing the invasion stage of the loricariid population and identifying appropriate management actions using the Blackburn et al. (2011) framework. The fish were sampled at nine different sites and three different depths over a period of twelve months, as well as when two ichthyological surveys were carried out on the Nseleni River system. This invasive fish has been located throughout the system and both male and female fish were collected. The smallest fish sampled was a fingerling of a day or two old and the smallest pregnant female was a mere 270mm TL. This is a clear indication that this fish is breeding in the river system.Although T. granifera and P. disjunctivus were abundant in the Nseleni/Mposa river system, it was not clear what their role in the system was, and in particular if they were competing with any of the indigenous species. Therefore, isotope samples were collected from numerous taxa over a two week period, with the exception of Pterygoplichthys disjunctivus samples, which were collected over 12 months. The δ13C and δ15N signatures of all samples were determined. The niche overlap between the invasive and indigenous snails was effectively zero (1.02E-13%), indicating no shared food resources. The medium ranges of dNRb (7.14) and dCRb (9.07) for the invasive fish indicate that it utilizes a wider range of food resources and trophic levels than the majority of indigenous fish. A medium CDb value (2.34) for the invasive fish species, P. disjunctivus, describes medium trophic diversity, with three indigenous species possessing higher diversity and three possessing lower diversity. Furtherresults indicated that there was no direct dietary competition between P. disjunctivus and indigenous species. Eichhornia crassipes was first recorded on the Nseleni River in 1978, and has been shown to have a significant negative impact on the biodiversity of the Nseleni/Mposa River system and therefore required a control intervention. Although biological control using the two weevil species Neochetina eichhornia (Warner) and N. bruchi (Hustache) has been credited with affecting a good level of control, the lack of a manipulated post-release evaluation experiments has undermined this statement. Five experimental plots of water hyacinth of 20m2 were sprayed with an insecticide to control weevils. After ten months the plants in the sprayed plots were significantly bigger and heavier than those in the control plots that had natural populations of the biological control agents. This study has shown unequivocally that biological control has contributed significantly to the control of water hyacinth on the Nseleni/Mposa River system.The management plan for the Enseleni Nature Reserve identifies the need to control invasive and/or exotic organisms within the boundary of the protected area. In addition, set guidelines have been implemented on how to control these organisms, so that indigenous organisms are least affected. Lack of control of exotic organisms can have serious consequences for indigenous species. It is therefore of utmost importance that the population dynamics of the invading organism be understood, what the potential impact could be and how to control them. Furthermore, it has also acknowledged the threat of possible exotic species invasions from outside of the protected area that might result in threats to the protected area and that these must be investigated, researched and managed.This thesis has identified Tarebia granifera, Pterygoplichthys disjunctivus and Eichhornia crassipes as being a threat to indigenous biodiversity within the protected area, as well as in adjacent areas to the protected area. The thesis will therefore investigate the hypothesis that both Tarebia granifera and Pterygoplichthys disjunctivus are having a direct negative effect on available food resources for indigenous species of organisms. In addition, this thesis will investigate if theNeochetina species that have previously been introduced onto E. crassipes are having any negative effect on this invasive alien aquatic plant.
- Full Text:
- Date Issued: 2015
- Authors: Jones, Roy William
- Date: 2015
- Subjects: Gastropoda -- South Africa , Introduced snails -- South Africa , Introduced mollusks -- South Africa , Loricariidae , Introduced fishes -- South Africa , Water hyacinth , Alien plants -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5928 , http://hdl.handle.net/10962/d1017806
- Description: Globalization has seen an unprecedented dispersal of exotic and alien species worldwide resulting in worldwide homogenization and sometimes extinction of indigenous or endemic taxa. When an exotic species becomes established in a new habitat the invasive organisms are capable of having an impact on indigenous community dynamics and the overall structure and function of ecosystems. Furthermore, the impact of invasion is determined by the geographical range, abundance and the per-capita or per-biomass effect of the invader. However, the success of the introduced organisms is reliant on their ability to acclimate to the physiochemical conditions of the newly invaded environment.Freshwater ecosystems are especially vulnerable to invasions because there are numerous potential routes of introduction including intentional pathways such as stocking, and unintentional pathways such as the release of ballast water and aquarium releases. Efforts to limit the introduction of invasive species or to manage established exotic populations are often hindered by insufficient understanding of the natural history of problematic species. Relatively little is known regarding the physiological tolerances of many taxa. Knowledge about specific species ecophysiological constraints allows for the prediction of future patterns of invasion more accurately, including where an introduced organism would probably survive, thrive and disperse. Furthermore, data on the physiological tolerances of an introduced exotic organism may provide data necessary for effective management and control. This studyinvestigated three invasive species in the Nseleni River system in a protected area in KwaZulu-Natal. The species studied were, Tarebia granifera (Quilted melania – Lamarck, 1822), Pterygoplichthys disjunctivus (Suckermouth armoured catfish - Weber, 1991) and Eichhornia crassipes (water hyacinth – (Martius) Solms-Laubach,). The Nseleni River flows into Lake Nsezi which is responsible for providing potable water to the surrounding towns and industry, as well as the surrounding rural communities. The Enseleni Nature reserve has become the centre for biodiversity dispersal in the immediate area, due to the change in landscape surrounding the protected area.An important step in developing alien invasive species management strategies in protected areas is determining their extent and invasive traits. Tarebia granifera is a prosobranch gastropod originally from South-East Asia that has become invasive in several countries around the world including South Africa. Snail populations were sampled at nine sites throughout the Nseleni/Mposa river system every six weeks over a twelve month period. The snail was abundant throughout the system, especially in shallow waters of less than 1m in depth.The first positive identification the loricariid catfish Pterygoplichthys disjunctivus for the Nseleni River was in 2006. The original introduction is believed to have been via the aquarium trade. The aim of the study was to assess the usefulness of the unified framework with regard to management of fish invasions by assessing the invasion stage of the loricariid population and identifying appropriate management actions using the Blackburn et al. (2011) framework. The fish were sampled at nine different sites and three different depths over a period of twelve months, as well as when two ichthyological surveys were carried out on the Nseleni River system. This invasive fish has been located throughout the system and both male and female fish were collected. The smallest fish sampled was a fingerling of a day or two old and the smallest pregnant female was a mere 270mm TL. This is a clear indication that this fish is breeding in the river system.Although T. granifera and P. disjunctivus were abundant in the Nseleni/Mposa river system, it was not clear what their role in the system was, and in particular if they were competing with any of the indigenous species. Therefore, isotope samples were collected from numerous taxa over a two week period, with the exception of Pterygoplichthys disjunctivus samples, which were collected over 12 months. The δ13C and δ15N signatures of all samples were determined. The niche overlap between the invasive and indigenous snails was effectively zero (1.02E-13%), indicating no shared food resources. The medium ranges of dNRb (7.14) and dCRb (9.07) for the invasive fish indicate that it utilizes a wider range of food resources and trophic levels than the majority of indigenous fish. A medium CDb value (2.34) for the invasive fish species, P. disjunctivus, describes medium trophic diversity, with three indigenous species possessing higher diversity and three possessing lower diversity. Furtherresults indicated that there was no direct dietary competition between P. disjunctivus and indigenous species. Eichhornia crassipes was first recorded on the Nseleni River in 1978, and has been shown to have a significant negative impact on the biodiversity of the Nseleni/Mposa River system and therefore required a control intervention. Although biological control using the two weevil species Neochetina eichhornia (Warner) and N. bruchi (Hustache) has been credited with affecting a good level of control, the lack of a manipulated post-release evaluation experiments has undermined this statement. Five experimental plots of water hyacinth of 20m2 were sprayed with an insecticide to control weevils. After ten months the plants in the sprayed plots were significantly bigger and heavier than those in the control plots that had natural populations of the biological control agents. This study has shown unequivocally that biological control has contributed significantly to the control of water hyacinth on the Nseleni/Mposa River system.The management plan for the Enseleni Nature Reserve identifies the need to control invasive and/or exotic organisms within the boundary of the protected area. In addition, set guidelines have been implemented on how to control these organisms, so that indigenous organisms are least affected. Lack of control of exotic organisms can have serious consequences for indigenous species. It is therefore of utmost importance that the population dynamics of the invading organism be understood, what the potential impact could be and how to control them. Furthermore, it has also acknowledged the threat of possible exotic species invasions from outside of the protected area that might result in threats to the protected area and that these must be investigated, researched and managed.This thesis has identified Tarebia granifera, Pterygoplichthys disjunctivus and Eichhornia crassipes as being a threat to indigenous biodiversity within the protected area, as well as in adjacent areas to the protected area. The thesis will therefore investigate the hypothesis that both Tarebia granifera and Pterygoplichthys disjunctivus are having a direct negative effect on available food resources for indigenous species of organisms. In addition, this thesis will investigate if theNeochetina species that have previously been introduced onto E. crassipes are having any negative effect on this invasive alien aquatic plant.
- Full Text:
- Date Issued: 2015
The executive government of the Cape of Good Hope, 1825-54
- Authors: Fryer, Alan Kenneth
- Date: 1959
- Subjects: Cape of Good Hope (South Africa) -- History -- 1795-1872
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2604 , http://hdl.handle.net/10962/d1011896
- Description: The study of administrative processes is a relaltively new one both in the field of history and sociology. In both disciplines what is required is study of the sructure and growth of adminstrative systems and of the impact of administrative action on the community it seeks to serve and which it often provokes. In the field of history, Professor F. Tout in his chapters on administrative history ... gave new vitality and understanding to medieval studies. In the main, South African history, though probably not more so than other Commonwealth countries, has been less fortunate. Preface, p. 1.
- Full Text:
- Date Issued: 1959
- Authors: Fryer, Alan Kenneth
- Date: 1959
- Subjects: Cape of Good Hope (South Africa) -- History -- 1795-1872
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2604 , http://hdl.handle.net/10962/d1011896
- Description: The study of administrative processes is a relaltively new one both in the field of history and sociology. In both disciplines what is required is study of the sructure and growth of adminstrative systems and of the impact of administrative action on the community it seeks to serve and which it often provokes. In the field of history, Professor F. Tout in his chapters on administrative history ... gave new vitality and understanding to medieval studies. In the main, South African history, though probably not more so than other Commonwealth countries, has been less fortunate. Preface, p. 1.
- Full Text:
- Date Issued: 1959