Supramolecular chemistry considerations of fluorenyl-derived host compounds
- Authors: McFarlane, Duncan William
- Date: 2024-12
- Subjects: Supramolecular chemistry , Organic compounds , Chemistry, Organic
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/69371 , vital:77227
- Description: This work examined various supramolecular aspects of 9-fluorenone-derived host compounds, namely 4,4’-(9-fluorenylidene)diphenol (H1), 9,9-(1,4-phenylene)bis(fluoren-9-ol) (H2), 9,9- (ethyne-1,2-diyl)bis(fluoren-9-ol) (H3) and 9,9-(biphenyl-4,4-diyl)bis(fluoren-9-ol) (H4). These compounds were successfully synthesized and then screened for their host ability for, and host behaviour in, various organic compounds. At the outset, molecular modelling calculations were carried out on each of the four host compounds. Various structural parameters and the geometries of the low energy conformers that were calculated were then compared with these aspects of the guest-free host molecules obtained from single crystal X-ray diffraction (SCXRD) analysis. The host behaviour of H1 was, furthermore, assessed in the presence of four alkylnitriles, namely acetonitrile (ACE), acrylonitrile (ACRY), propionitrile (PROP) and butyronitrile (BUT). All four guests complexed with H1 with 1:1 host:guest (H:G) ratios. From SCXRD analyses, each of the complexes crystallized in the monoclinic crystal system and the centrosymmetric space group P21/n, and the host packing was isostructural in each instance. The complexes were stabilized by a plethora of short inter- and intramolecular contacts. The thermal stabilities of the four complexes were also examined together with Hirshfeld surface considerations. Finally, lattice energy calculations were carried out and the results of these compared with the relative thermal stabilities of the four complexes. The compounds H2 and H3 were examined for their selectivity behaviour in mixtures of aniline, N-methylaniline and N,N’-dimethylaniline (ANI, NMA and DMA). Both host compounds were able to form complexes with ANI and DMA with various H:G ratios, while only H3 possessed enclathration ability for NMA (H:G 1:1). SCXRD analyses showed that all of the complexes were stabilized by means of classical (host)O‒H···N(guest) hydrogen bonds in addition to other short contacts. Equimolar binary guest competition experiments with H2 revealed an extremely high host selectivity for DMA (ANI/DMA and DMA/NMA experiments furnished crystals with > 91% DMA), while the experiment with all three anilines present also resulted in a complex with an , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-12
- Authors: McFarlane, Duncan William
- Date: 2024-12
- Subjects: Supramolecular chemistry , Organic compounds , Chemistry, Organic
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/69371 , vital:77227
- Description: This work examined various supramolecular aspects of 9-fluorenone-derived host compounds, namely 4,4’-(9-fluorenylidene)diphenol (H1), 9,9-(1,4-phenylene)bis(fluoren-9-ol) (H2), 9,9- (ethyne-1,2-diyl)bis(fluoren-9-ol) (H3) and 9,9-(biphenyl-4,4-diyl)bis(fluoren-9-ol) (H4). These compounds were successfully synthesized and then screened for their host ability for, and host behaviour in, various organic compounds. At the outset, molecular modelling calculations were carried out on each of the four host compounds. Various structural parameters and the geometries of the low energy conformers that were calculated were then compared with these aspects of the guest-free host molecules obtained from single crystal X-ray diffraction (SCXRD) analysis. The host behaviour of H1 was, furthermore, assessed in the presence of four alkylnitriles, namely acetonitrile (ACE), acrylonitrile (ACRY), propionitrile (PROP) and butyronitrile (BUT). All four guests complexed with H1 with 1:1 host:guest (H:G) ratios. From SCXRD analyses, each of the complexes crystallized in the monoclinic crystal system and the centrosymmetric space group P21/n, and the host packing was isostructural in each instance. The complexes were stabilized by a plethora of short inter- and intramolecular contacts. The thermal stabilities of the four complexes were also examined together with Hirshfeld surface considerations. Finally, lattice energy calculations were carried out and the results of these compared with the relative thermal stabilities of the four complexes. The compounds H2 and H3 were examined for their selectivity behaviour in mixtures of aniline, N-methylaniline and N,N’-dimethylaniline (ANI, NMA and DMA). Both host compounds were able to form complexes with ANI and DMA with various H:G ratios, while only H3 possessed enclathration ability for NMA (H:G 1:1). SCXRD analyses showed that all of the complexes were stabilized by means of classical (host)O‒H···N(guest) hydrogen bonds in addition to other short contacts. Equimolar binary guest competition experiments with H2 revealed an extremely high host selectivity for DMA (ANI/DMA and DMA/NMA experiments furnished crystals with > 91% DMA), while the experiment with all three anilines present also resulted in a complex with an , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-12
Synthesis of two tartaric acid-derived host compounds and their behaviour in mixed pyridines and mixed heterocyclic guest compounds
- Authors: Recchia, Daniella Loridana
- Date: 2024-12
- Subjects: Compounds -- guest/host , Chemistry, Organic , Chemistry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/69441 , vital:77256
- Description: The host compounds (4R,5R)-bis(diphenylhydroxymethyl)-2-spiro-1’-cyclopentane-1,3-dioxolane (TADDOL5) and (4R,5R)-bis(diphenylhydroxymethyl)-2-spiro-1’-cyclohexane-1,3-dioxolane (TADDOL6) were successfully synthesized after initially reacting diethyl tartrate with either 1,1-dimethoxycyclopentane or 1,1-dimethoxycyclohexane to afford the intermediates diethyl 2-spiro-1’-cyclopentane-1,3-dioxolan-4,5-dicarboxylate or diethyl 2-spiro-1’-cyclohexane-1,3-dioxolan-4,5-dicarboxylate. These were then each subjected to a Grignard addition reaction with PhMgBr to furnish TADDOL5 and TADDOL6 in reasonably high yields (77 and 80%, respectively). Computational calculations were performed on TADDOL5 and TADDOL6 using the software programs Avogadro and ORCA. The optimised geometries of these host molecules were obtained using the MMFF94 force field in Avogadro, while ORCA was used to perform the computational modelling at the BLYP level using the 6-31G*, 6-31G**, 6-311G* and 6-311G** basis sets and, also, the B3LYP functional (with the same basis sets) to obtain the three lowest energy conformers. The final geometries of each conformer for both TADDOL5 and TADDOL6 at the B3LYP 6-311G* level were overlaid with the molecules obtained from their crystal structures. Significantly different geometries were thus noted for the calculated conformers compared with the guest-free TADDOL5 and TADDOL6 structures obtained from the SCXRD experiments. When TADDOL5 was crystallized independently from each of PYR, 2MP, 3MP and 4MP, 1:1 H:G inclusion complexes formed in each instance. This host compound was then investigated for its host separation ability of mixed pyridines through supramolecular chemistry protocols. These mixed guest experiments revealed that TADDOL5 possessed a notable selectivity towards 3MP and PYR (in the absence of 3MP) followed by 4MP and 2MP, and it was shown that TADDOL5 is a suitable host candidate for the separation of many of the mixed pyridines employed here. The results of the SCXRD analyses indicated that the only significant (host)π···π(guest) stacking interaction present was between TADDOL5 and the most favoured guest species PYR and 3MP. Furthermore, significantly shorter (host)O‒H···N(guest) hydrogen bonds were also observed in the complexes formed between this host compound and 3MP and PYR compared with these bonds involving disfavoured 4MP and 2MP. Hirshfeld surface considerations provided an explanation for the affinity of TADDOL5 for PYR (but not 3MP), while thermal analyses successfully explained this affinity: the 3MP-containing complex with the most preferred guest species was the most thermally stable one, followed by TADDOL5·PYR, as obtained through a consideration of the Ton values (the temperature at which the guest release event initiated) of the four complexes. As with TADDOL5, TADDOL6 formed 1:1 H:G inclusion compounds with each of the four pyridines. TADDOL6 was, furthermore, also assessed for its separation ability for mixed pyridines, and these guest competition experiments showed that the selectivity of TADDOL6 was for PYR and 3MP (in the absence of PYR), followed by 4MP and 2MP. (Interestingly, TADDOL5 preferred 3MP and then PYR, while both host compounds disfavoured 4MP and 2MP.) The results obtained in this work indicated that TADDOL6 may also serve as an efficient host candidate for the separation of many of these pyridyl solutions. SCXRD experiments demonstrated that the only significant (host)π···π(guest) stacking interactions were those between TADDOL6 and preferred PYR and 3MP, as was the case for TADDOL5. These experiments also revealed that the strongest (host)O‒H···N(guest) hydrogen bonds were between TADDOL6 and these favoured guest species. A consideration of Hirshfeld surfaces and quantification of the (guest)N···H(host) intermolecular interactions correlated with the host selectivity order, as did thermal analyses, where the Ton values confirmed that the thermal stabilities of these complexes decreased in the guest order PYR > 3MP > 4MP > 2MP. The behaviour of TADDOL5 was further investigated in guest compounds DIO, PYR, PIP and MOR. Each guest solvent formed 1:1 H:G inclusion complexes with the host species, with the exception of DIO, which formed a 2:1 H:G complex. Mixed guest experiments revealed a clear preference for PIP and MOR, while PYR and DIO were less favoured. The host selectivity was demonstrated to be in the order PIP > MOR > PYR > DIO. SCXRD experiments showed that TADDOL5 formed a much shorter (and more linear) (host)O‒H···N(guest) hydrogen bond with the most favoured guest, PIP, compared to those involving MOR and PYR. A (host)O‒H···O(guest) hydrogen bond was also observed in the DIO-containing inclusion complex. A consideration of the Hirshfeld surface interactions was not useful in explaining the host selectivity order for these heterocyclic guests, but thermal analyses confirmed that the most stable complex was the one with favoured PIP, followed by those with PYR, MOR and DIO. TADDOL6, on the other hand, formed 1:1 H:G inclusion compounds with all four of the heterocyclic guest solvents. Experiments in mixed guests showed that the selectivity of this host compound for these guests was in the order PYR > PIP > MOR > DIO, which differed from the TADDOL5 (which favoured PIP and then MOR). Interestingly, the strongest classical hydrogen bond was not formed with the most favoured guest PYR, but with PIP instead (this bond with TADDOL5 was also strongest with PIP, but PIP was favoured in that work). Hirshfeld surface investigations again were not useful in understanding the host selectivity behaviour. However, thermal analyses agreed with the observations made in the mixed guest experiments: the most stable complex was with PYR (favoured) and the least stable one was with DIO (least preferred). , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-12
- Authors: Recchia, Daniella Loridana
- Date: 2024-12
- Subjects: Compounds -- guest/host , Chemistry, Organic , Chemistry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/69441 , vital:77256
- Description: The host compounds (4R,5R)-bis(diphenylhydroxymethyl)-2-spiro-1’-cyclopentane-1,3-dioxolane (TADDOL5) and (4R,5R)-bis(diphenylhydroxymethyl)-2-spiro-1’-cyclohexane-1,3-dioxolane (TADDOL6) were successfully synthesized after initially reacting diethyl tartrate with either 1,1-dimethoxycyclopentane or 1,1-dimethoxycyclohexane to afford the intermediates diethyl 2-spiro-1’-cyclopentane-1,3-dioxolan-4,5-dicarboxylate or diethyl 2-spiro-1’-cyclohexane-1,3-dioxolan-4,5-dicarboxylate. These were then each subjected to a Grignard addition reaction with PhMgBr to furnish TADDOL5 and TADDOL6 in reasonably high yields (77 and 80%, respectively). Computational calculations were performed on TADDOL5 and TADDOL6 using the software programs Avogadro and ORCA. The optimised geometries of these host molecules were obtained using the MMFF94 force field in Avogadro, while ORCA was used to perform the computational modelling at the BLYP level using the 6-31G*, 6-31G**, 6-311G* and 6-311G** basis sets and, also, the B3LYP functional (with the same basis sets) to obtain the three lowest energy conformers. The final geometries of each conformer for both TADDOL5 and TADDOL6 at the B3LYP 6-311G* level were overlaid with the molecules obtained from their crystal structures. Significantly different geometries were thus noted for the calculated conformers compared with the guest-free TADDOL5 and TADDOL6 structures obtained from the SCXRD experiments. When TADDOL5 was crystallized independently from each of PYR, 2MP, 3MP and 4MP, 1:1 H:G inclusion complexes formed in each instance. This host compound was then investigated for its host separation ability of mixed pyridines through supramolecular chemistry protocols. These mixed guest experiments revealed that TADDOL5 possessed a notable selectivity towards 3MP and PYR (in the absence of 3MP) followed by 4MP and 2MP, and it was shown that TADDOL5 is a suitable host candidate for the separation of many of the mixed pyridines employed here. The results of the SCXRD analyses indicated that the only significant (host)π···π(guest) stacking interaction present was between TADDOL5 and the most favoured guest species PYR and 3MP. Furthermore, significantly shorter (host)O‒H···N(guest) hydrogen bonds were also observed in the complexes formed between this host compound and 3MP and PYR compared with these bonds involving disfavoured 4MP and 2MP. Hirshfeld surface considerations provided an explanation for the affinity of TADDOL5 for PYR (but not 3MP), while thermal analyses successfully explained this affinity: the 3MP-containing complex with the most preferred guest species was the most thermally stable one, followed by TADDOL5·PYR, as obtained through a consideration of the Ton values (the temperature at which the guest release event initiated) of the four complexes. As with TADDOL5, TADDOL6 formed 1:1 H:G inclusion compounds with each of the four pyridines. TADDOL6 was, furthermore, also assessed for its separation ability for mixed pyridines, and these guest competition experiments showed that the selectivity of TADDOL6 was for PYR and 3MP (in the absence of PYR), followed by 4MP and 2MP. (Interestingly, TADDOL5 preferred 3MP and then PYR, while both host compounds disfavoured 4MP and 2MP.) The results obtained in this work indicated that TADDOL6 may also serve as an efficient host candidate for the separation of many of these pyridyl solutions. SCXRD experiments demonstrated that the only significant (host)π···π(guest) stacking interactions were those between TADDOL6 and preferred PYR and 3MP, as was the case for TADDOL5. These experiments also revealed that the strongest (host)O‒H···N(guest) hydrogen bonds were between TADDOL6 and these favoured guest species. A consideration of Hirshfeld surfaces and quantification of the (guest)N···H(host) intermolecular interactions correlated with the host selectivity order, as did thermal analyses, where the Ton values confirmed that the thermal stabilities of these complexes decreased in the guest order PYR > 3MP > 4MP > 2MP. The behaviour of TADDOL5 was further investigated in guest compounds DIO, PYR, PIP and MOR. Each guest solvent formed 1:1 H:G inclusion complexes with the host species, with the exception of DIO, which formed a 2:1 H:G complex. Mixed guest experiments revealed a clear preference for PIP and MOR, while PYR and DIO were less favoured. The host selectivity was demonstrated to be in the order PIP > MOR > PYR > DIO. SCXRD experiments showed that TADDOL5 formed a much shorter (and more linear) (host)O‒H···N(guest) hydrogen bond with the most favoured guest, PIP, compared to those involving MOR and PYR. A (host)O‒H···O(guest) hydrogen bond was also observed in the DIO-containing inclusion complex. A consideration of the Hirshfeld surface interactions was not useful in explaining the host selectivity order for these heterocyclic guests, but thermal analyses confirmed that the most stable complex was the one with favoured PIP, followed by those with PYR, MOR and DIO. TADDOL6, on the other hand, formed 1:1 H:G inclusion compounds with all four of the heterocyclic guest solvents. Experiments in mixed guests showed that the selectivity of this host compound for these guests was in the order PYR > PIP > MOR > DIO, which differed from the TADDOL5 (which favoured PIP and then MOR). Interestingly, the strongest classical hydrogen bond was not formed with the most favoured guest PYR, but with PIP instead (this bond with TADDOL5 was also strongest with PIP, but PIP was favoured in that work). Hirshfeld surface investigations again were not useful in understanding the host selectivity behaviour. However, thermal analyses agreed with the observations made in the mixed guest experiments: the most stable complex was with PYR (favoured) and the least stable one was with DIO (least preferred). , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-12
Synthesis, X-Ray characterization, spectroscopic and Hirshfeld surface analysis of dimeric metal centers featuring phenacyl-esters
- Authors: Qomfo, Vuyiseka
- Date: 2024-12
- Subjects: Spectrum analysis , Spectroscopic imaging , Diagnostic imaging -- Digital techniques
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/69426 , vital:77254
- Description: In this study, the synthesis and characterization of carboxylate paddlewheel copper complexes were investigated and reported. The complexes consist of O-, and N- donor ligands which coordinated in the apical positions of the copper (II) paddlewheel complexes. The primary focus was the investigation of the influence of the incoming substituents on the structure; more especially with regards to the spectral properties and thermal properties of the synthesized compounds. Synthesized complexes ranged from simple mononuclear complexes and dinuclear dimers to supramolecular 1D networks and a tetranuclear copper (II) compound. Characterization of complexes was done using analytical, and spectroscopic techniques such as single crystal diffraction studies, FT-IR spectroscopy, thermal analysis and Hirshfeld surface analysis. Structural analysis of the mononuclear complex obtained in the reaction of the Cu2(o-CH3-PhCO2)4(THF)2 with the ligand ,2-oxo-phenylethylnicotinate, revealed a square-planar geometry. The series of dinuclear paddlewheel complexes obtained with ligands (L = THF (1), C4H8O (2), C14H11NO3 (3)) revealed a square pyramidal geometry with the methyl-substituted phenyl carboxylate groups bridging the two copper atoms in the syn-syn coordination mode. Extended supramolecular complexes were synthesized via the reaction of three synthesized structurally bifunctional organic ligands and the tetrakis(μ-carboxylato-O,O)dicopper(II) core. Two of the six reactions synthesized successfully to form paddlewheel cage type structures; resulting in dinuclear paddlewheel complexes with four carboxylate ligands occupying the equatorial positions and the bifunctional ligands coordinating in the apical positions. Four of the nine reactions produced mononuclear copper complexes. Due to the inconsistent power supply because of load-shedding, the other three crystals synthesized could not be confirmed by single-crystal diffraction before the submission of this thesis. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-12
- Authors: Qomfo, Vuyiseka
- Date: 2024-12
- Subjects: Spectrum analysis , Spectroscopic imaging , Diagnostic imaging -- Digital techniques
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/69426 , vital:77254
- Description: In this study, the synthesis and characterization of carboxylate paddlewheel copper complexes were investigated and reported. The complexes consist of O-, and N- donor ligands which coordinated in the apical positions of the copper (II) paddlewheel complexes. The primary focus was the investigation of the influence of the incoming substituents on the structure; more especially with regards to the spectral properties and thermal properties of the synthesized compounds. Synthesized complexes ranged from simple mononuclear complexes and dinuclear dimers to supramolecular 1D networks and a tetranuclear copper (II) compound. Characterization of complexes was done using analytical, and spectroscopic techniques such as single crystal diffraction studies, FT-IR spectroscopy, thermal analysis and Hirshfeld surface analysis. Structural analysis of the mononuclear complex obtained in the reaction of the Cu2(o-CH3-PhCO2)4(THF)2 with the ligand ,2-oxo-phenylethylnicotinate, revealed a square-planar geometry. The series of dinuclear paddlewheel complexes obtained with ligands (L = THF (1), C4H8O (2), C14H11NO3 (3)) revealed a square pyramidal geometry with the methyl-substituted phenyl carboxylate groups bridging the two copper atoms in the syn-syn coordination mode. Extended supramolecular complexes were synthesized via the reaction of three synthesized structurally bifunctional organic ligands and the tetrakis(μ-carboxylato-O,O)dicopper(II) core. Two of the six reactions synthesized successfully to form paddlewheel cage type structures; resulting in dinuclear paddlewheel complexes with four carboxylate ligands occupying the equatorial positions and the bifunctional ligands coordinating in the apical positions. Four of the nine reactions produced mononuclear copper complexes. Due to the inconsistent power supply because of load-shedding, the other three crystals synthesized could not be confirmed by single-crystal diffraction before the submission of this thesis. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-12
The effect of the 2020 to 2021 alcohol ban on alcohol consumption and consumer preferences
- Authors: Dullabh, Curtis
- Date: 2024-12
- Subjects: Drinking customs , Alcoholic beverages , Consumer behavior -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/69565 , vital:77714
- Description: This study examines the effect of the alcohol ban from 2020 to 2021 on consumer preferences and consumption habits. The COVID-19 virus was first detected in China, in 2019. The virus spread rapidly, crippling health care systems across the world. As the disease spread, countries began looking at ways to reduce the strain on the health care system caused by other factors (Gu, 2020). The first case in South Africa was recorded on 5 March 2020. South Africa reacted quickly and decided to implement a hard lockdown on alcohol, 22 days after the first case was recorded (Murhula & Nunlall, 2021). Due to the high number of trauma-related cases, which affected the healthcare system and South Africa’s reputation for being a country that consumes high volumes of alcohol, the government needed swift action. This alcohol ban sent shock waves across the country and alcohol consumers began to panic (BBC, 2020). In addition, the alcohol ban caused people to alter their consumption behaviours and some even resorted to homebrewing alcohol during the lockdown. Alcohol was available through the illicit market, which came at a premium price with limited options. This study originated from the alcohol ban, as consumers were exposed to brands, they otherwise would not have considered if all alcohol beverages were available. The scarcity of alcohol products, the excessive prices of alcohol and the effort it took to obtain alcohol, played a major role in altering drinking behaviours and brand preferences post the alcohol ban. Results from the study indicated that age and gender played no significant role in alcohol consumption, brand preference across categories were affected with two of nine alcohol categories experiencing a decline in consumption, from before to after the ban. During the ban, the majority of respondents consumed alcohol with some resorting to homebrewed alcohol, which showed a significant increase in consumption during the ban. The opportunity to further this study would be to investigate the increase in low alcoholic beverages and non-alcohol beverages as key avenues for organisations within the alcohol industry. , Thesis (MBA) -- Faculty of Business and Economic Sciences, Business School, 2024
- Full Text:
- Date Issued: 2024-12
- Authors: Dullabh, Curtis
- Date: 2024-12
- Subjects: Drinking customs , Alcoholic beverages , Consumer behavior -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/69565 , vital:77714
- Description: This study examines the effect of the alcohol ban from 2020 to 2021 on consumer preferences and consumption habits. The COVID-19 virus was first detected in China, in 2019. The virus spread rapidly, crippling health care systems across the world. As the disease spread, countries began looking at ways to reduce the strain on the health care system caused by other factors (Gu, 2020). The first case in South Africa was recorded on 5 March 2020. South Africa reacted quickly and decided to implement a hard lockdown on alcohol, 22 days after the first case was recorded (Murhula & Nunlall, 2021). Due to the high number of trauma-related cases, which affected the healthcare system and South Africa’s reputation for being a country that consumes high volumes of alcohol, the government needed swift action. This alcohol ban sent shock waves across the country and alcohol consumers began to panic (BBC, 2020). In addition, the alcohol ban caused people to alter their consumption behaviours and some even resorted to homebrewing alcohol during the lockdown. Alcohol was available through the illicit market, which came at a premium price with limited options. This study originated from the alcohol ban, as consumers were exposed to brands, they otherwise would not have considered if all alcohol beverages were available. The scarcity of alcohol products, the excessive prices of alcohol and the effort it took to obtain alcohol, played a major role in altering drinking behaviours and brand preferences post the alcohol ban. Results from the study indicated that age and gender played no significant role in alcohol consumption, brand preference across categories were affected with two of nine alcohol categories experiencing a decline in consumption, from before to after the ban. During the ban, the majority of respondents consumed alcohol with some resorting to homebrewed alcohol, which showed a significant increase in consumption during the ban. The opportunity to further this study would be to investigate the increase in low alcoholic beverages and non-alcohol beverages as key avenues for organisations within the alcohol industry. , Thesis (MBA) -- Faculty of Business and Economic Sciences, Business School, 2024
- Full Text:
- Date Issued: 2024-12
The inhibitory effects of cannabinoids from cannabis sativa on the enzymes dipeptidyl peptidase-IV, sucrase and maltase as a new therapeutic treatment for type 2 diabetes
- Authors: Viljoen, Zenobia
- Date: 2024-12
- Subjects: Diabetes -- Treatment , Cannabinoids -- Therapeutic use , Medical Marijuana -- therapeutic use
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/69516 , vital:77264
- Description: Type 2 diabetes is one of the most prevalent diseases worldwide. The treatments used to manage diabetes often have severe side effects and patients develop resistance to traditional treatment. The project aimed to test if phytocannabinoids from Cannabis sativa inhibited key enzymes involved in glycaemic homeostatic regulation, namely dipeptidyl peptidase 4 (DPP-4), sucrase, and maltase. This study investigated the inhibitory effects of 3 M-128 M cannabidiol (CBD), cannabinol (CBN), cannabigerol (CBG), and Δ9- tetrahydrocannabinol (THC). CD spectroscopy was used to investigate the changes in the secondary structure of DPP-4 with interacting inhibitors. The effect of 1.25, 2.5, and 5 mg/kg rat THC cannabis extract on the activity of DPP-4 in blood plasma and rat pancreatic tissue of the diabetic rat model and obese rat model. The effect of 1.25, 2.5, and 5 mg/kg rat THC cannabis extract on glucagon concentration in the blood plasma of the diabetic rat model and obese rat model was investigated. The carbohydrate digestive enzymes namely -amylase, -glucosidase and maltase are not inhibited by any of the cannabinoids. CBN had inhibitory effects on sucrase. CBN, CBG, and CBD are mixed inhibitors of DPP-4, thus they can inhibit DPP-4 competitively and uncompetitively depending on the concentration of the cannabinoid. THC was shown in kinetic and rat model studies to be a very weak inhibitor of DPP-4. CD spectroscopy showed that sitagliptin (FDA-approved drug and competitive inhibitor) and CBG mimic the denatured structure of DPP-4. CBD, CBN and THC mimic the free (active) form of DPP-4. A reduction in pancreatic DPP-4 activity was observed with 2.5 and 5 mg/kg rat THC (diabetic model). This study showed that diet plays a role in glycaemic dysregulation (obese rat model) and that insulin-resistant rats had four times higher glucagon levels compared to the lean control (diabetic model). 1.25 mg/kg rat THC reduced blood plasma DPP-4 activity and blood plasma glucagon. Cannabis sativa can be a feasible treatment to help manage type 2 diabetes by inhibiting DPP-4, especially medical strains of Cannabis sativa with high concentrations of CBD and CBG. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-12
- Authors: Viljoen, Zenobia
- Date: 2024-12
- Subjects: Diabetes -- Treatment , Cannabinoids -- Therapeutic use , Medical Marijuana -- therapeutic use
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/69516 , vital:77264
- Description: Type 2 diabetes is one of the most prevalent diseases worldwide. The treatments used to manage diabetes often have severe side effects and patients develop resistance to traditional treatment. The project aimed to test if phytocannabinoids from Cannabis sativa inhibited key enzymes involved in glycaemic homeostatic regulation, namely dipeptidyl peptidase 4 (DPP-4), sucrase, and maltase. This study investigated the inhibitory effects of 3 M-128 M cannabidiol (CBD), cannabinol (CBN), cannabigerol (CBG), and Δ9- tetrahydrocannabinol (THC). CD spectroscopy was used to investigate the changes in the secondary structure of DPP-4 with interacting inhibitors. The effect of 1.25, 2.5, and 5 mg/kg rat THC cannabis extract on the activity of DPP-4 in blood plasma and rat pancreatic tissue of the diabetic rat model and obese rat model. The effect of 1.25, 2.5, and 5 mg/kg rat THC cannabis extract on glucagon concentration in the blood plasma of the diabetic rat model and obese rat model was investigated. The carbohydrate digestive enzymes namely -amylase, -glucosidase and maltase are not inhibited by any of the cannabinoids. CBN had inhibitory effects on sucrase. CBN, CBG, and CBD are mixed inhibitors of DPP-4, thus they can inhibit DPP-4 competitively and uncompetitively depending on the concentration of the cannabinoid. THC was shown in kinetic and rat model studies to be a very weak inhibitor of DPP-4. CD spectroscopy showed that sitagliptin (FDA-approved drug and competitive inhibitor) and CBG mimic the denatured structure of DPP-4. CBD, CBN and THC mimic the free (active) form of DPP-4. A reduction in pancreatic DPP-4 activity was observed with 2.5 and 5 mg/kg rat THC (diabetic model). This study showed that diet plays a role in glycaemic dysregulation (obese rat model) and that insulin-resistant rats had four times higher glucagon levels compared to the lean control (diabetic model). 1.25 mg/kg rat THC reduced blood plasma DPP-4 activity and blood plasma glucagon. Cannabis sativa can be a feasible treatment to help manage type 2 diabetes by inhibiting DPP-4, especially medical strains of Cannabis sativa with high concentrations of CBD and CBG. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-12
The legality of euthanasia conducted by medical practitioners
- Authors: Davids, Sesam Isipho
- Date: 2024-12
- Subjects: Euthanasia -- Law and legislation , Assisted suicide -- Law and legislation , Euthanasia -- Moral and ethical aspects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/68681 , vital:77081
- Description: Euthanasia remains a contentious subject of debate in countries around the world and in South Africa. The South African court system has been faced with requests for the decriminalisation of euthanasia. However, it remains illegal to practice euthanasia in South Africa. This is set by common law as there is no legislation formally regulating euthanasia. Euthanasia provides relief from suffering for patients with terminal illnesses that cause severe suffering and a decrease in their quality of life. Individual autonomy is recognised as patients are given the ability to choose how to end their lives once they make the decision to terminate their lives. In this study, an examination on physician-assisted euthanasia and its current legal position in South Africa will be conducted. Key terms are defined, such as euthanasia - distinguishing active and passive euthanasia as well as physician-assisted suicide. South African law permits the withdrawal of life-sustaining treatments which may be viewed as passive euthanasia. This is done with the consent of the patient and the medical practitioners involved are not held criminally liable should the withholding of treatment cause the death of the patient. Relevant constitutional rights will be examined to make a case for the legalisation of physician-assisted euthanasia. These rights include the right to dignity, the right to life, the right to equality, the right to freedom of religion, belief and opinion, and the limitation clause. Common law, case law and statutory law will also be considered. The recommendations of the South African Law Commission in its report (project 86) will be examined as well. An analysis will be conducted on how foreign jurisdictions have accepted physician-assisted euthanasia and implemented legislative measures to safeguard and regulate how medical practitioners practice it. Canada is an example of such a jurisdiction and an analysis has been conducted on how courts in Canada have made a case for the decriminalisation of physician-assisted euthanasia. Canadian courts relied on rights such as the right to life and freedom of opinion. viii When arguing for or against the legalisation of euthanasia, the ethical perspectives of both arguments must be considered. The ‘slippery slope’ will be discussed to demonstrate an ethical argument against euthanasia. The ethical framework of utilitarianism will be discussed as an argument for euthanasia. In line with the title of this research, the physician’s role in the process of euthanasia will also be discussed. After weighing the key arguments, this research concludes that physician-assisted euthanasia ought to be legalised in South Africa. Recommendations are further suggested on how euthanasia ought to be regulated should it be legalised. The recommendations serve as a means of addressing the possibility of abuse and illegal conduct from medical practitioners and the public. Through this study, the aim is to contribute to the debate on physician-assisted euthanasia and to advance the development of a euthanasia-related legislation in South Africa. , Thesis (LLM) -- Faculty of Law, School of Criminal and Procedural Law, 2024
- Full Text:
- Date Issued: 2024-12
- Authors: Davids, Sesam Isipho
- Date: 2024-12
- Subjects: Euthanasia -- Law and legislation , Assisted suicide -- Law and legislation , Euthanasia -- Moral and ethical aspects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/68681 , vital:77081
- Description: Euthanasia remains a contentious subject of debate in countries around the world and in South Africa. The South African court system has been faced with requests for the decriminalisation of euthanasia. However, it remains illegal to practice euthanasia in South Africa. This is set by common law as there is no legislation formally regulating euthanasia. Euthanasia provides relief from suffering for patients with terminal illnesses that cause severe suffering and a decrease in their quality of life. Individual autonomy is recognised as patients are given the ability to choose how to end their lives once they make the decision to terminate their lives. In this study, an examination on physician-assisted euthanasia and its current legal position in South Africa will be conducted. Key terms are defined, such as euthanasia - distinguishing active and passive euthanasia as well as physician-assisted suicide. South African law permits the withdrawal of life-sustaining treatments which may be viewed as passive euthanasia. This is done with the consent of the patient and the medical practitioners involved are not held criminally liable should the withholding of treatment cause the death of the patient. Relevant constitutional rights will be examined to make a case for the legalisation of physician-assisted euthanasia. These rights include the right to dignity, the right to life, the right to equality, the right to freedom of religion, belief and opinion, and the limitation clause. Common law, case law and statutory law will also be considered. The recommendations of the South African Law Commission in its report (project 86) will be examined as well. An analysis will be conducted on how foreign jurisdictions have accepted physician-assisted euthanasia and implemented legislative measures to safeguard and regulate how medical practitioners practice it. Canada is an example of such a jurisdiction and an analysis has been conducted on how courts in Canada have made a case for the decriminalisation of physician-assisted euthanasia. Canadian courts relied on rights such as the right to life and freedom of opinion. viii When arguing for or against the legalisation of euthanasia, the ethical perspectives of both arguments must be considered. The ‘slippery slope’ will be discussed to demonstrate an ethical argument against euthanasia. The ethical framework of utilitarianism will be discussed as an argument for euthanasia. In line with the title of this research, the physician’s role in the process of euthanasia will also be discussed. After weighing the key arguments, this research concludes that physician-assisted euthanasia ought to be legalised in South Africa. Recommendations are further suggested on how euthanasia ought to be regulated should it be legalised. The recommendations serve as a means of addressing the possibility of abuse and illegal conduct from medical practitioners and the public. Through this study, the aim is to contribute to the debate on physician-assisted euthanasia and to advance the development of a euthanasia-related legislation in South Africa. , Thesis (LLM) -- Faculty of Law, School of Criminal and Procedural Law, 2024
- Full Text:
- Date Issued: 2024-12
The lived experiences of final-year undergraduate diagnostic radiography students applying radiation protection measures during clinical practice
- Authors: Campbell, Sydney Samuel
- Date: 2024-12
- Subjects: Radiographers , College students -- South Africa , Experiential learning
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/68311 , vital:76973
- Description: Radiographers use ionising radiation to produce radiographic images and the use of ionising radiation in healthcare has both benefits and risks for patients and healthcare professionals. It is therefore important that radiographers mitigate the risks associated with ionising radiation. It is for this reason that radiation protection measures are applied to ensure the safety of patients, staff, and the public. Furthermore, radiographers are also responsible for mentoring radiography students and inculcate the use of radiation protection measures when students undergo their workplace learning. This mentoring takes place in the clinical setting with its characteristics that may or may not advance the application of radiation protection measures. The aim of this study was to investigate the lived experiences of final-year undergraduate radiography students applying radiation protection measures in the clinical setting and to propose strategies to foster the integration of radiation protection theory into clinical practice. This study was located in the interpretivist paradigm using phenomenology as a research method and theoretical framework to achieve the stated aim. The target population for this qualitative study included all registered final-year undergraduate radiography students at the local university who perform their WPL at the accredited training hospitals in the Eastern Cape Province as this cohort of students have more clinical experience than the first-, second- and third-year students. The target population comprised 28 students. Purposive sampling was employed to select the group of radiography students to interview. The study used phenomenological interviews as a data collection tool and the collected data was explicated using a self-developed method. The trustworthiness of the study was ensured by applying Guba’s model of trustworthiness that includes credibility, transferability, confirmability, dependability and authenticity and was further enhanced by reflecting on the balanced integration, openness, concreteness, and resonance of the study. This study employed an ethical framework referred to as principlism that includes the notions of autonomy, beneficence, non-maleficence and justice.Data explication was conducted using three cycles of explication. Cycle one produced interpretive profiles for each participant. The interpretive profiles revealed the life histories of each participant as well as the utterances of participants related to the three sub-questions. Cycle two produced four themes. Theme one described participants’ being with others such as radiographers, clinical supervisors, medical doctors, and patients and revealed the tension between participants’ belonging and being unwanted. Theme two characterised the clinical setting as a place where several factors flow together to provide participants with their individualised experiences. Theme two revealed the emotional distress; the learning through trial-and-error; the independent learning; learning that is coupled with humiliation as experienced by participants. The clinical space was also characterised as a place to be survived, a place where students have to be inconspicuous and understand the acceptable levels of engagement with others. It is also a place where theory and practice at times is in alignment at other times not in alignment. The clinical setting could also be a place of self-doubt and insecurity, a place of personal growth, and a place where historical events are significant. Theme three disclosed the unspoken lessons that were conveyed through the actions and behaviours of individuals in the clinical environment. Unintended lesson one is that radiation protection measures are not important. Lesson two suggest that classroom teaching about radiation protection is not valid in the clinical setting, and finally that incivility towards radiography students is acceptable. Theme four revealed the difficulties experienced by radiography students when navigating ethical dilemmas. The theme revealed radiographers’ and radiologists’ indifference towards radiation protection, the non-application of radiation protection measures, and the inconsistency and apathy towards radiation protection measures. Cycle three viewed the experiences of participants through the lens of Dasein’s disclosedness. This revealed the exclusive language used by participants, the largely negative mood and participants’ disconnection from the imaging department.Finally, the study presented new and important insights by probing the topic of radiation protection in a novel way by using phenomenology to focus on the lived experiences of final-year undergraduate students applying radiation protection measures in the clinical setting. The findings of the study also allowed for the development of Enhancement strategies that could be used by institutions of higher education to promote the integration of the theory and practice of radiation protection measures in the clinical setting. It is recommended, though, that a study that includes all South African institutions of higher learning offering radiography be conducted using phenomenology. Furthermore, the views of South African radiographers and clinical supervisors should also be elicited to corroborate the views of participants in this study. , Thesis (PhD) -- Faculty of Education, School of Secondary Education, 2024
- Full Text:
- Date Issued: 2024-12
- Authors: Campbell, Sydney Samuel
- Date: 2024-12
- Subjects: Radiographers , College students -- South Africa , Experiential learning
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/68311 , vital:76973
- Description: Radiographers use ionising radiation to produce radiographic images and the use of ionising radiation in healthcare has both benefits and risks for patients and healthcare professionals. It is therefore important that radiographers mitigate the risks associated with ionising radiation. It is for this reason that radiation protection measures are applied to ensure the safety of patients, staff, and the public. Furthermore, radiographers are also responsible for mentoring radiography students and inculcate the use of radiation protection measures when students undergo their workplace learning. This mentoring takes place in the clinical setting with its characteristics that may or may not advance the application of radiation protection measures. The aim of this study was to investigate the lived experiences of final-year undergraduate radiography students applying radiation protection measures in the clinical setting and to propose strategies to foster the integration of radiation protection theory into clinical practice. This study was located in the interpretivist paradigm using phenomenology as a research method and theoretical framework to achieve the stated aim. The target population for this qualitative study included all registered final-year undergraduate radiography students at the local university who perform their WPL at the accredited training hospitals in the Eastern Cape Province as this cohort of students have more clinical experience than the first-, second- and third-year students. The target population comprised 28 students. Purposive sampling was employed to select the group of radiography students to interview. The study used phenomenological interviews as a data collection tool and the collected data was explicated using a self-developed method. The trustworthiness of the study was ensured by applying Guba’s model of trustworthiness that includes credibility, transferability, confirmability, dependability and authenticity and was further enhanced by reflecting on the balanced integration, openness, concreteness, and resonance of the study. This study employed an ethical framework referred to as principlism that includes the notions of autonomy, beneficence, non-maleficence and justice.Data explication was conducted using three cycles of explication. Cycle one produced interpretive profiles for each participant. The interpretive profiles revealed the life histories of each participant as well as the utterances of participants related to the three sub-questions. Cycle two produced four themes. Theme one described participants’ being with others such as radiographers, clinical supervisors, medical doctors, and patients and revealed the tension between participants’ belonging and being unwanted. Theme two characterised the clinical setting as a place where several factors flow together to provide participants with their individualised experiences. Theme two revealed the emotional distress; the learning through trial-and-error; the independent learning; learning that is coupled with humiliation as experienced by participants. The clinical space was also characterised as a place to be survived, a place where students have to be inconspicuous and understand the acceptable levels of engagement with others. It is also a place where theory and practice at times is in alignment at other times not in alignment. The clinical setting could also be a place of self-doubt and insecurity, a place of personal growth, and a place where historical events are significant. Theme three disclosed the unspoken lessons that were conveyed through the actions and behaviours of individuals in the clinical environment. Unintended lesson one is that radiation protection measures are not important. Lesson two suggest that classroom teaching about radiation protection is not valid in the clinical setting, and finally that incivility towards radiography students is acceptable. Theme four revealed the difficulties experienced by radiography students when navigating ethical dilemmas. The theme revealed radiographers’ and radiologists’ indifference towards radiation protection, the non-application of radiation protection measures, and the inconsistency and apathy towards radiation protection measures. Cycle three viewed the experiences of participants through the lens of Dasein’s disclosedness. This revealed the exclusive language used by participants, the largely negative mood and participants’ disconnection from the imaging department.Finally, the study presented new and important insights by probing the topic of radiation protection in a novel way by using phenomenology to focus on the lived experiences of final-year undergraduate students applying radiation protection measures in the clinical setting. The findings of the study also allowed for the development of Enhancement strategies that could be used by institutions of higher education to promote the integration of the theory and practice of radiation protection measures in the clinical setting. It is recommended, though, that a study that includes all South African institutions of higher learning offering radiography be conducted using phenomenology. Furthermore, the views of South African radiographers and clinical supervisors should also be elicited to corroborate the views of participants in this study. , Thesis (PhD) -- Faculty of Education, School of Secondary Education, 2024
- Full Text:
- Date Issued: 2024-12
The optimisation of Eucalyptus regeneration practices for improved survival, growth and uniformity in South African pulpwood plantations
- Authors: Hechter, Ullrich
- Date: 2024-12
- Subjects: Eucalyptus -- Regeneration -- South Africa , Forests and forestry -- Economic aspects , Forests and forestry
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/68862 , vital:77135
- Description: Commercial forestry plantations in South Africa play an important role in the economy of the country, contributing 1.2% towards the gross domestic product. Currently plantation forests occupy 1.1% (1.2 million hectares) of the South African land surface, of which 75 000 hectares are re-established each year. Eucalypts constitute 43% of planted area, of which 88% is grown for pulpwood. Achieving high tree survival (>90%) is important in terms of optimising rotation-end yield. The industry origin of a 90% survival benchmark is unclear, although company procedures incorporate this as the minimum threshold in terms of re-establishment success. Past research indicates that most mortality occurs within a narrow period post-establishment and is often associated with substandard re-establishment practices and/or a stressed micro-environment. An improved understanding is needed about the various mitigation measures needed to minimize mortality during eucalypt re-establishment. Before making decisions related to mortality mitigation measures, comprehensive data are required as to their commercial applicability as well as outcomes from multiple trials that accurately quantify any impacts on tree survival and financial return. The overall purpose of this dissertation was the optimisation of Eucalyptus re-establishment practices for improved survival, growth and uniformity in South African pulpwood plantations. To achieve this, five inter-linked objectives were determined. The first objective was to highlight the most important factors contributing to increased mortality in eucalypt plantations during re-establishment. This was achieved through conducting a literature review. Citations were ranked in terms of credibility, with the importance ratings (derived from the literature sources) applied to the different factors affecting survival and growth during eucalypt re-establishment. Of the various factors impacting early eucalypt mortality, water stress and planting stock quality were considered highly important. The manner and quality of site preparation (soil and slash), planting practices (planting depth included), timing of planting (during dry, hot periods), various post-planting operations (incorrect fertiliser placement or herbicide drift) and insect pests and diseases also contribute to mortality, but to a lesser extent. These factors cannot be considered in isolation due to the complex interactions that exist between them and determining the primary causes of mortality can be elusive, especially as their impacts tend to be additive by nature. The second objective was to link survival to silvicultural treatments, site-related physiographic factors and climatic variables in South Africa. This was achieved by conducting an integrated analysis of 43 Eucalyptus trials. Of the seven re-establishment practices considered, watering, planting depth and fertiliser application were significant, with plant size, pitting method, residue management and insecticide application were not significant. However, when environmental variables were included within the analyses, there were significant site x treatment interactions for planting depth, plant size, residue management and fertiliser application. This highlights the importance of taking site related factors into consideration when interpreting the causes of mortality. The third objective was to determine the interaction between planting density and mortality on Eucalyptus growth, uniformity and financial yield at rotation end in South Africa. This was carried out to verify whether planting at different densities may be used as a preventative (before planting) mitigation measure. One trial was used to answer four keys sub-objectives: 1) The impact of three planting densities (1 102, 1 500, 1 959 SPH) with no mortality on yield at rotation-end; 2) The impact of mortality (0%, 10%, 20%, 30%, 40%) on rotation-end yield; 3) The quantification of tree performance when planting at a higher density and accepting a certain degree of mortality; and 4) The financial impact of different planting densities and mortality on rotation-end profit. Higher planting densities resulted in smaller individual trees, but with an increase in stand level performance. At rotation-end, lower mortality (0% and 10%) had significantly higher volumes ha-1 than the higher mortality (30% and 40%). Planting at higher densities (1 722 and 1 959 SPH) and accepting a certain degree of mortality resulted in non-significant differences for volume at rotation-end compared to the fully stocked 1 500 SPH treatment. A higher SPH resulted in a higher yield, but with an increase in estimated establishment/tending and harvesting costs. In contrast, an increase in mortality and/or lower SPH (in the absence of mortality) resulted in more variable stand growth, together with an increase in estimated machine harvesting productivity and reduced costs. Irrespective of SPH, the higher the mortality the greater the loss of income, with the best profit within each treatment related to full stocking (0% mortality). Within the higher panting densities, the profit gained following low mortality (10 and 20%) was similar to that of no mortality (0%), indicating that higher mortality may be tolerated when planting at higher densities, confirming the 90% survival threshold the industry aims to achieve post-establishment. The fourth objective was to determine if silviculture intervention (blanking at 1, 2 and 3 months or coppicing and interplanting at 6 months) will result in acceptable eucalypt stocking, if mortality is higher than 10% (remedial mitigation measure). Data from a re-establishment trial were analysed to determine which of the mitigation measures performed best in terms of stocking and growth. Coppicing and interplanting with larger plants was not a viable option as a mitigation measure for mortality as most of the coppice shoots have died. This may have been a result of frost. Although high re-establishment costs may be incurred, disaster clearing to waste followed by replanting is an option if mortality is unacceptably high (as opposed to leaving the stand as is). The results of this objective confirm that blanking as the current Best Operating Practice is still appropriate in South African forestry (i.e., try to have survival >90% and blank as soon as possible to retain >90% of stems). Blanked plants do contribute to volume, but for this to occur, blanking should be carried out within 4 weeks after planting to gain maximum benefit. In addition, it highlights the importance of implementing remedial mitigation measures to achieve >90% survival so as to gain maximum benefit. Using the outcomes from objectives 1-4, the fifth objective focussed on the development of a decision support system (DSS) for implementation of mitigation measures to improve survival within commercial eucalypt pulpwood plantations in South Africa. Improved survival starts with the implementation of good re-establishment practices and good quality planting stock. Mitigation measures for poor survival can be implemented either prior to re-establishment (before mortality occurs) or post re-establishment (after mortality has occurred). If poor survival still occurs after the implementation of good silviculture practices and pre-re-establishment mitigation practices (planting at higher densities), one should consider the various options available in terms of post re-establishment mitigation practices (remedial practices) such as blanking or replanting if mortality is high. Overall, the outcomes from this dissertation provide benchmark data and derived information as to the necessity for various mortality mitigation options within the commercial forestry sector in South Africa. In addition, the DSS will assist with decision making in terms of implementing the best silviculture practices and mitigation measures for improved survival during eucalypt re-establishment in South African pulpwood plantations. , Thesis (PhD) -- Faculty of Science, School of Natural Resource Science & Management, 2024
- Full Text:
- Date Issued: 2024-12
- Authors: Hechter, Ullrich
- Date: 2024-12
- Subjects: Eucalyptus -- Regeneration -- South Africa , Forests and forestry -- Economic aspects , Forests and forestry
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/68862 , vital:77135
- Description: Commercial forestry plantations in South Africa play an important role in the economy of the country, contributing 1.2% towards the gross domestic product. Currently plantation forests occupy 1.1% (1.2 million hectares) of the South African land surface, of which 75 000 hectares are re-established each year. Eucalypts constitute 43% of planted area, of which 88% is grown for pulpwood. Achieving high tree survival (>90%) is important in terms of optimising rotation-end yield. The industry origin of a 90% survival benchmark is unclear, although company procedures incorporate this as the minimum threshold in terms of re-establishment success. Past research indicates that most mortality occurs within a narrow period post-establishment and is often associated with substandard re-establishment practices and/or a stressed micro-environment. An improved understanding is needed about the various mitigation measures needed to minimize mortality during eucalypt re-establishment. Before making decisions related to mortality mitigation measures, comprehensive data are required as to their commercial applicability as well as outcomes from multiple trials that accurately quantify any impacts on tree survival and financial return. The overall purpose of this dissertation was the optimisation of Eucalyptus re-establishment practices for improved survival, growth and uniformity in South African pulpwood plantations. To achieve this, five inter-linked objectives were determined. The first objective was to highlight the most important factors contributing to increased mortality in eucalypt plantations during re-establishment. This was achieved through conducting a literature review. Citations were ranked in terms of credibility, with the importance ratings (derived from the literature sources) applied to the different factors affecting survival and growth during eucalypt re-establishment. Of the various factors impacting early eucalypt mortality, water stress and planting stock quality were considered highly important. The manner and quality of site preparation (soil and slash), planting practices (planting depth included), timing of planting (during dry, hot periods), various post-planting operations (incorrect fertiliser placement or herbicide drift) and insect pests and diseases also contribute to mortality, but to a lesser extent. These factors cannot be considered in isolation due to the complex interactions that exist between them and determining the primary causes of mortality can be elusive, especially as their impacts tend to be additive by nature. The second objective was to link survival to silvicultural treatments, site-related physiographic factors and climatic variables in South Africa. This was achieved by conducting an integrated analysis of 43 Eucalyptus trials. Of the seven re-establishment practices considered, watering, planting depth and fertiliser application were significant, with plant size, pitting method, residue management and insecticide application were not significant. However, when environmental variables were included within the analyses, there were significant site x treatment interactions for planting depth, plant size, residue management and fertiliser application. This highlights the importance of taking site related factors into consideration when interpreting the causes of mortality. The third objective was to determine the interaction between planting density and mortality on Eucalyptus growth, uniformity and financial yield at rotation end in South Africa. This was carried out to verify whether planting at different densities may be used as a preventative (before planting) mitigation measure. One trial was used to answer four keys sub-objectives: 1) The impact of three planting densities (1 102, 1 500, 1 959 SPH) with no mortality on yield at rotation-end; 2) The impact of mortality (0%, 10%, 20%, 30%, 40%) on rotation-end yield; 3) The quantification of tree performance when planting at a higher density and accepting a certain degree of mortality; and 4) The financial impact of different planting densities and mortality on rotation-end profit. Higher planting densities resulted in smaller individual trees, but with an increase in stand level performance. At rotation-end, lower mortality (0% and 10%) had significantly higher volumes ha-1 than the higher mortality (30% and 40%). Planting at higher densities (1 722 and 1 959 SPH) and accepting a certain degree of mortality resulted in non-significant differences for volume at rotation-end compared to the fully stocked 1 500 SPH treatment. A higher SPH resulted in a higher yield, but with an increase in estimated establishment/tending and harvesting costs. In contrast, an increase in mortality and/or lower SPH (in the absence of mortality) resulted in more variable stand growth, together with an increase in estimated machine harvesting productivity and reduced costs. Irrespective of SPH, the higher the mortality the greater the loss of income, with the best profit within each treatment related to full stocking (0% mortality). Within the higher panting densities, the profit gained following low mortality (10 and 20%) was similar to that of no mortality (0%), indicating that higher mortality may be tolerated when planting at higher densities, confirming the 90% survival threshold the industry aims to achieve post-establishment. The fourth objective was to determine if silviculture intervention (blanking at 1, 2 and 3 months or coppicing and interplanting at 6 months) will result in acceptable eucalypt stocking, if mortality is higher than 10% (remedial mitigation measure). Data from a re-establishment trial were analysed to determine which of the mitigation measures performed best in terms of stocking and growth. Coppicing and interplanting with larger plants was not a viable option as a mitigation measure for mortality as most of the coppice shoots have died. This may have been a result of frost. Although high re-establishment costs may be incurred, disaster clearing to waste followed by replanting is an option if mortality is unacceptably high (as opposed to leaving the stand as is). The results of this objective confirm that blanking as the current Best Operating Practice is still appropriate in South African forestry (i.e., try to have survival >90% and blank as soon as possible to retain >90% of stems). Blanked plants do contribute to volume, but for this to occur, blanking should be carried out within 4 weeks after planting to gain maximum benefit. In addition, it highlights the importance of implementing remedial mitigation measures to achieve >90% survival so as to gain maximum benefit. Using the outcomes from objectives 1-4, the fifth objective focussed on the development of a decision support system (DSS) for implementation of mitigation measures to improve survival within commercial eucalypt pulpwood plantations in South Africa. Improved survival starts with the implementation of good re-establishment practices and good quality planting stock. Mitigation measures for poor survival can be implemented either prior to re-establishment (before mortality occurs) or post re-establishment (after mortality has occurred). If poor survival still occurs after the implementation of good silviculture practices and pre-re-establishment mitigation practices (planting at higher densities), one should consider the various options available in terms of post re-establishment mitigation practices (remedial practices) such as blanking or replanting if mortality is high. Overall, the outcomes from this dissertation provide benchmark data and derived information as to the necessity for various mortality mitigation options within the commercial forestry sector in South Africa. In addition, the DSS will assist with decision making in terms of implementing the best silviculture practices and mitigation measures for improved survival during eucalypt re-establishment in South African pulpwood plantations. , Thesis (PhD) -- Faculty of Science, School of Natural Resource Science & Management, 2024
- Full Text:
- Date Issued: 2024-12
The review of a disciplinary finding or sanction in terms of section 158(1)(h) of the labour relations act 66 of 1995
- Authors: August, Joshua Cliff
- Date: 2024-12
- Subjects: Labor discipline , Labor laws and legislation -- South Africa , South Africa.-- Labour Relations Act, 1995
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/68670 , vital:77080
- Description: When an employer subjects an employee to a formal disciplinary process, the employer appoints a presiding officer to whom it cedes either wholly or partly its decision-making powers. Wholly in that the presiding officer would render a finding and impose a sanction. Partly, in that the presiding officer would render a finding and only provide the employer with a recommendation on sanction, which the employer would either accept or reject. The State in its capacity as employer has been afforded the ability to utilise section 158(1)(h) of the Labour Relations Act, 1995 (LRA) to review the decisions of presiding officers appointed over internal disciplinary proceedings. Despite the wording of section 158(1)(h), the courts have restricted its use by employees employed by the State. The courts have held that a State employee would have to utilise the ordinary dispute resolution pathways made available in the LRA to challenge the decisions the State takes in its capacity as an employer. When exercising the prerogative to discipline, all employers, including the State, must primarily comply with the substantive and procedural requirements outlined in Schedule 8 of the LRA. Notwithstanding the primary measure of fairness, the employer’s decision to discipline and dismiss would also be pitched and measured against its adopted internal disciplinary code and procedure document. It has been questioned in a Labour Court judgement whether the State should continue to be afforded the benefit of the section 158(1)(h) review. The Labour Court judgement ventures into the consequences the use of section 158(1)(h) would have on the unfair dismissal dispute resolution pathway afforded by the LRA and proposed that it would be ideal for the State to utilise alternatives when attempting to alter the sanction or finding of its internal presiding officers. The alternatives proposed include the internal review of findings or sanctions, the unilateral substitution of sanctions, increasing sanctions on appeal and the practice of subjecting the employee to a second hearing. Applying the alternatives to the current circumstances and collective bargaining agreements applicable in the public service, the State would not be able to utilise the alternatives, save for subjecting the employee to a second hearing in exceptional circumstances. In all other instances, including convening an internal review, increasing a sanction during an appeal, or unilaterally substituting the sanction would conflict with the prevailing internal disciplinary code and procedure in the public service. In as much as the Labour Court judgment attempts to put into perspective the consequences the use of section 158(1)(h) would have on the subsequent dispute resolution pathways, the State should not be unduly bound by irrational findings or sanctions imposed by presiding officers appointed to preside over its internal disciplinary hearings. , Thesis (LLM) -- Faculty of Law, School of Mercantile Law, 2024
- Full Text:
- Date Issued: 2024-12
- Authors: August, Joshua Cliff
- Date: 2024-12
- Subjects: Labor discipline , Labor laws and legislation -- South Africa , South Africa.-- Labour Relations Act, 1995
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/68670 , vital:77080
- Description: When an employer subjects an employee to a formal disciplinary process, the employer appoints a presiding officer to whom it cedes either wholly or partly its decision-making powers. Wholly in that the presiding officer would render a finding and impose a sanction. Partly, in that the presiding officer would render a finding and only provide the employer with a recommendation on sanction, which the employer would either accept or reject. The State in its capacity as employer has been afforded the ability to utilise section 158(1)(h) of the Labour Relations Act, 1995 (LRA) to review the decisions of presiding officers appointed over internal disciplinary proceedings. Despite the wording of section 158(1)(h), the courts have restricted its use by employees employed by the State. The courts have held that a State employee would have to utilise the ordinary dispute resolution pathways made available in the LRA to challenge the decisions the State takes in its capacity as an employer. When exercising the prerogative to discipline, all employers, including the State, must primarily comply with the substantive and procedural requirements outlined in Schedule 8 of the LRA. Notwithstanding the primary measure of fairness, the employer’s decision to discipline and dismiss would also be pitched and measured against its adopted internal disciplinary code and procedure document. It has been questioned in a Labour Court judgement whether the State should continue to be afforded the benefit of the section 158(1)(h) review. The Labour Court judgement ventures into the consequences the use of section 158(1)(h) would have on the unfair dismissal dispute resolution pathway afforded by the LRA and proposed that it would be ideal for the State to utilise alternatives when attempting to alter the sanction or finding of its internal presiding officers. The alternatives proposed include the internal review of findings or sanctions, the unilateral substitution of sanctions, increasing sanctions on appeal and the practice of subjecting the employee to a second hearing. Applying the alternatives to the current circumstances and collective bargaining agreements applicable in the public service, the State would not be able to utilise the alternatives, save for subjecting the employee to a second hearing in exceptional circumstances. In all other instances, including convening an internal review, increasing a sanction during an appeal, or unilaterally substituting the sanction would conflict with the prevailing internal disciplinary code and procedure in the public service. In as much as the Labour Court judgment attempts to put into perspective the consequences the use of section 158(1)(h) would have on the subsequent dispute resolution pathways, the State should not be unduly bound by irrational findings or sanctions imposed by presiding officers appointed to preside over its internal disciplinary hearings. , Thesis (LLM) -- Faculty of Law, School of Mercantile Law, 2024
- Full Text:
- Date Issued: 2024-12
Toughened wood plastic composites for low technology and advanced manufacturing applications
- Authors: Mabutho, Briswell
- Date: 2024-12
- Subjects: Plastic-impregnated wood , Polymeric composites
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/69360 , vital:77225
- Description: The utilization of wood plastic composites (WPCs) has increasingly emerged as an appealing alternative for products where traditional wood and conventional composites would typically be used. This is primarily due to their cost-effectiveness, mouldability, recyclability, renewability, and potential biodegradability. However, the incorporation of wood flour (WF) in thermoplastics to produce WPCs presents several challenges, two of which are addressed in the current study: the WF-thermoplastic matrix adhesion, and the resulting brittleness of the WPC. The hydrophilic nature of WF filler and the hydrophobic polypropylene matrix, which typically lead to poor mixing due to their differing surface energies. Consequently, the current research focuses on enhancing WF-matrix (i.e. polypropylene, PP) adhesion and dispersion through compatibilization using maleic anhydride grafted polypropylene (MAPP). Additionally, the brittleness of WPC, exacerbated by the WF content, is addressed through the incorporation of crumb rubber (CR), a process commonly referred to as "toughening" the WPC. Prior to the use of CR in WPCs, optimization of the CR amount and compatibility within the PP-matrix were conducted to establish a toughening system that would achieve the highest impact strength without significantly affecting the tensile strength. The CR was compatibilized by employing dynamic vulcanization of varying amounts of ethylene propylene diene monomer rubber (EPDM) in the CR/PP blends using both sulphur and dicumyl peroxide cure systems. The results indicated that the sulphur dynamic cure system exhibited higher crosslinking efficiency, as reflected by the highest impact strength. Furthermore, to enhance WPC processability and adhesion, WF alkalization was conducted following a central composite design to optimize treatment temperature, time, and alkali concentration. This optimization resulted in improved WPC processability and mechanical properties at mild alkalization conditions. Subsequently, the optimum CR/EPDM dynamic cure system was employed to toughen both untreated and alkalized WPCs, resulting in toughened WPCs with improved thermal stability, impact strength, and elongation at break, while the tensile strength was only slightly compromised. , Thesis (PhD) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-12
- Authors: Mabutho, Briswell
- Date: 2024-12
- Subjects: Plastic-impregnated wood , Polymeric composites
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/69360 , vital:77225
- Description: The utilization of wood plastic composites (WPCs) has increasingly emerged as an appealing alternative for products where traditional wood and conventional composites would typically be used. This is primarily due to their cost-effectiveness, mouldability, recyclability, renewability, and potential biodegradability. However, the incorporation of wood flour (WF) in thermoplastics to produce WPCs presents several challenges, two of which are addressed in the current study: the WF-thermoplastic matrix adhesion, and the resulting brittleness of the WPC. The hydrophilic nature of WF filler and the hydrophobic polypropylene matrix, which typically lead to poor mixing due to their differing surface energies. Consequently, the current research focuses on enhancing WF-matrix (i.e. polypropylene, PP) adhesion and dispersion through compatibilization using maleic anhydride grafted polypropylene (MAPP). Additionally, the brittleness of WPC, exacerbated by the WF content, is addressed through the incorporation of crumb rubber (CR), a process commonly referred to as "toughening" the WPC. Prior to the use of CR in WPCs, optimization of the CR amount and compatibility within the PP-matrix were conducted to establish a toughening system that would achieve the highest impact strength without significantly affecting the tensile strength. The CR was compatibilized by employing dynamic vulcanization of varying amounts of ethylene propylene diene monomer rubber (EPDM) in the CR/PP blends using both sulphur and dicumyl peroxide cure systems. The results indicated that the sulphur dynamic cure system exhibited higher crosslinking efficiency, as reflected by the highest impact strength. Furthermore, to enhance WPC processability and adhesion, WF alkalization was conducted following a central composite design to optimize treatment temperature, time, and alkali concentration. This optimization resulted in improved WPC processability and mechanical properties at mild alkalization conditions. Subsequently, the optimum CR/EPDM dynamic cure system was employed to toughen both untreated and alkalized WPCs, resulting in toughened WPCs with improved thermal stability, impact strength, and elongation at break, while the tensile strength was only slightly compromised. , Thesis (PhD) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2024
- Full Text:
- Date Issued: 2024-12
Vocational Education and the relentless struggles of TVET graduates in the Eastern Cape, South Africa: A Freirean approach
- Authors: Majola, Ezekiel
- Date: 2024-12
- Subjects: Vocational education -- Eastern Cape -- South Africa , Technical education -- Eastern Cape -- South Africa , School-to-work transition -- Eastern Cape -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/${Handle} , vital:76985
- Description: This study employs Paulo Freire’s framework to contribute to debates surrounding social justice and transformation in vocational education and training (TVET). By offering a critical perspective on dominant discourse and practices, it challenges prevailing trajectories of powerful knowledge and inherent assumptions and biases in TVET. Drawing on a Freirean framework, the research provides insights to develop more equitable and transformative practices by addressing power, privilege, and social inequality in TVET. Through dialogue and collaboration with students, it promotes critical consciousness and relevant skills and knowledge. Highlighting the significance of context, it underscores the need to understand the social and cultural context of learning. Demonstrating the potential of a Freirean framework to challenge the status quo, it promotes more equitable and empowering practices in TVET. The chosen methodology for this study is Participatory Action Research (PAR), integrating theory, action, and participation to address social issues. Recruiting 15 NC(V) graduates from Algoa TVET College, forming a Learning Cycle Group (LCG), the study aimed to comprehend graduates’ experiences, challenges, and opportunities. Life narrative interviews and LCG meetings generated data, ensuring every participant had a voice and strengthening group cohesion. Data were grounded in ethical values such as respect, equality, inclusion, democratic participation, active learning, making a difference, collective action, and personal integrity. Employing Paulo Freire’s theoretical framework, this study offers a novel perspective on TVET in South Africa, fostering dialogue with TVET students to challenge conventional discourses. It aimed to develop an alternative conceptualisation of TVET by incorporating student experiences and perspectives, promoting positive change through dialogue and addressing power dynamics and social justice issues. The study explores Powell’s (2014) question regarding TVET colleges’ role in expanding opportunities for students and asks: “How do TVET graduates experience life after graduation? Are they empowered and satisfied with their social status?” Sub-questions inquire about students’ expectations upon enrolling, opportunities after completing NC(V) programs, and the extent to which TVET colleges address unemployment and socio-economic injustices, aiming to inspire the development of praxis and frameworks that better serve the needs of TVET graduates and address social concerns.The study’s findings, analysed through Freire’s ideology in “We Make the Road by Walking” (1990) and “Pedagogy of Hope” (1994), reveal that the NC(V) program predominantly attracts underprivileged students and is rarely their first choice. This research highlights that the NC(V) program does not fully empower or transform students’ circumstances, instead perpetuating cycles of poverty, unemployment, and social inequality—contrary to Freire’s vision of education as a tool for liberation and societal change. The program fails to provide meaningful employment opportunities, leaving graduates often unemployed or in low-paying jobs, unable to escape poverty. This underscores the program’s inadequacies. Furthermore, insufficient support structures and practical application opportunities further diminish graduates’ employability. The study’s findings emphasise the need for systemic reforms in the NC(V) program. Embracing Freire’s principles and moving beyond traditional banking education models to more inclusive, participatory approaches is essential. This transformation is crucial for the TVET system to genuinely empower students and foster significant personal and societal change. , Thesis (PhD) -- Faculty of Education, School of Secondary School Education, 2024
- Full Text:
- Date Issued: 2024-12
- Authors: Majola, Ezekiel
- Date: 2024-12
- Subjects: Vocational education -- Eastern Cape -- South Africa , Technical education -- Eastern Cape -- South Africa , School-to-work transition -- Eastern Cape -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/${Handle} , vital:76985
- Description: This study employs Paulo Freire’s framework to contribute to debates surrounding social justice and transformation in vocational education and training (TVET). By offering a critical perspective on dominant discourse and practices, it challenges prevailing trajectories of powerful knowledge and inherent assumptions and biases in TVET. Drawing on a Freirean framework, the research provides insights to develop more equitable and transformative practices by addressing power, privilege, and social inequality in TVET. Through dialogue and collaboration with students, it promotes critical consciousness and relevant skills and knowledge. Highlighting the significance of context, it underscores the need to understand the social and cultural context of learning. Demonstrating the potential of a Freirean framework to challenge the status quo, it promotes more equitable and empowering practices in TVET. The chosen methodology for this study is Participatory Action Research (PAR), integrating theory, action, and participation to address social issues. Recruiting 15 NC(V) graduates from Algoa TVET College, forming a Learning Cycle Group (LCG), the study aimed to comprehend graduates’ experiences, challenges, and opportunities. Life narrative interviews and LCG meetings generated data, ensuring every participant had a voice and strengthening group cohesion. Data were grounded in ethical values such as respect, equality, inclusion, democratic participation, active learning, making a difference, collective action, and personal integrity. Employing Paulo Freire’s theoretical framework, this study offers a novel perspective on TVET in South Africa, fostering dialogue with TVET students to challenge conventional discourses. It aimed to develop an alternative conceptualisation of TVET by incorporating student experiences and perspectives, promoting positive change through dialogue and addressing power dynamics and social justice issues. The study explores Powell’s (2014) question regarding TVET colleges’ role in expanding opportunities for students and asks: “How do TVET graduates experience life after graduation? Are they empowered and satisfied with their social status?” Sub-questions inquire about students’ expectations upon enrolling, opportunities after completing NC(V) programs, and the extent to which TVET colleges address unemployment and socio-economic injustices, aiming to inspire the development of praxis and frameworks that better serve the needs of TVET graduates and address social concerns.The study’s findings, analysed through Freire’s ideology in “We Make the Road by Walking” (1990) and “Pedagogy of Hope” (1994), reveal that the NC(V) program predominantly attracts underprivileged students and is rarely their first choice. This research highlights that the NC(V) program does not fully empower or transform students’ circumstances, instead perpetuating cycles of poverty, unemployment, and social inequality—contrary to Freire’s vision of education as a tool for liberation and societal change. The program fails to provide meaningful employment opportunities, leaving graduates often unemployed or in low-paying jobs, unable to escape poverty. This underscores the program’s inadequacies. Furthermore, insufficient support structures and practical application opportunities further diminish graduates’ employability. The study’s findings emphasise the need for systemic reforms in the NC(V) program. Embracing Freire’s principles and moving beyond traditional banking education models to more inclusive, participatory approaches is essential. This transformation is crucial for the TVET system to genuinely empower students and foster significant personal and societal change. , Thesis (PhD) -- Faculty of Education, School of Secondary School Education, 2024
- Full Text:
- Date Issued: 2024-12
(In)security communities in Africa: small arms and light weapons norm compliance by the economic community of West African states
- Authors: Pokoo, John Mark
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/467093 , vital:76814
- Description: Access restricted. Expected release in 2026. , Thesis (PhD) -- Faculty of Humanities, Political and International Studies, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Pokoo, John Mark
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/467093 , vital:76814
- Description: Access restricted. Expected release in 2026. , Thesis (PhD) -- Faculty of Humanities, Political and International Studies, 2024
- Full Text:
- Date Issued: 2024-10-11
A case study of GADRA’s community-engaged praxis for educational transformation
- Authors: Msomi, Nqobile Nomonde
- Date: 2024-10-11
- Subjects: Non-governmental organizations South Africa , Community psychology , Afrocentrism , Foucauldian discourse analysis , Education South Africa , Transformative learning South Africa
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/464864 , vital:76552 , DOI https://doi.org/10.21504/10962/464864
- Description: Although South Africa has achieved considerable steps in development over the last thirty years, post-apartheid South Africa is characterised by widespread poverty, high unemployment and systemic inequality. According to the country’s National Planning Commission, education is central to achieving the overarching democratic goals of eliminating poverty and reducing inequality. This positions education as an important site for the liberation and well-being of our country’s majority. This case study takes a community psychology perspective on education; more specifically the education-development nexus wherein Non-Governmental Organisations (NGOs) are centrally positioned. NGOs are contentiously positioned in the development discourse. Nonetheless, they have played a key role with regards to siding with the poor, the excluded, persistently marginalised and oppressed majority and to bringing about social justice, following South Africa’s colonial and apartheid histories, as well as in the current democratic dispensation. This study situates a local NGO, GADRA Education, within the country’s socio-political and educational landscape. Founded in the 1950s and located in Makhanda, it has been operating in the rural Eastern Cape province for more than sixty years. In the present-day, GADRA Education positions itself at the centre of a dense network of education institutions in Makhanda, including Rhodes University, and collaborates with a number of education stakeholders in the small city. The case study consisted of two consecutive phases: a Foucauldian discourse analysis of GADRA’s annual reports between 2012 and 2021, followed by individual narrative interviews with 13 organisational members. An Africa(n)-centred community psychology orientation, revealed counter-discourse to the national “crisis in education” discourse surrounding the NGO. The discourse of crisis produced the legitimation for GADRA Education’s continued existence, action and embeddedness in Makhanda. The discourse of transformation informed their modes of support across primary, secondary and higher education. The discourse of access and participation constructed the NGO as a bridge and link between phases of education. The discourse of collaborative partnerships enabled solidarity between state and non-state actors towards educational change. Finally, the discourse of development positioned development at a grassroots level. These constellations formed GADRA Education’s counter-discourse, which produced the Organisation’s apparatus of resistance, formulated as situated praxis. The 5 organisational members’ narratives revealed the apparatus’s impacts on the subjectivities of youth in Makhanda in engendering hope and driving educational change in the city. In contrast to conceptions of education NGOs who work in the public schooling sector making little progress in dismantling educational inequity, this study illustrates the techniques of resistance leveraged, in the context of collaborative partnerships, by the local NGO. These techniques have wider applicability for education-development practitioners concerned with transformative change in their educational locales. It illustrates the principles and modes by which NGOs can operate in solidarity with the persistently marginalised majority, and thus contribute to shaping our imagined educational futures. I argue that psychology is a useful site to think about justice. Critical psychological theory can enable a deeper understanding of practice that contributes to impactful community organisation, intervention and resistance in the country’s education sector. The operationalisation of the values and principles of community psychology can make important contributions at the nexus of theory and practice in working towards educational, and ultimately social, change. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Msomi, Nqobile Nomonde
- Date: 2024-10-11
- Subjects: Non-governmental organizations South Africa , Community psychology , Afrocentrism , Foucauldian discourse analysis , Education South Africa , Transformative learning South Africa
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/464864 , vital:76552 , DOI https://doi.org/10.21504/10962/464864
- Description: Although South Africa has achieved considerable steps in development over the last thirty years, post-apartheid South Africa is characterised by widespread poverty, high unemployment and systemic inequality. According to the country’s National Planning Commission, education is central to achieving the overarching democratic goals of eliminating poverty and reducing inequality. This positions education as an important site for the liberation and well-being of our country’s majority. This case study takes a community psychology perspective on education; more specifically the education-development nexus wherein Non-Governmental Organisations (NGOs) are centrally positioned. NGOs are contentiously positioned in the development discourse. Nonetheless, they have played a key role with regards to siding with the poor, the excluded, persistently marginalised and oppressed majority and to bringing about social justice, following South Africa’s colonial and apartheid histories, as well as in the current democratic dispensation. This study situates a local NGO, GADRA Education, within the country’s socio-political and educational landscape. Founded in the 1950s and located in Makhanda, it has been operating in the rural Eastern Cape province for more than sixty years. In the present-day, GADRA Education positions itself at the centre of a dense network of education institutions in Makhanda, including Rhodes University, and collaborates with a number of education stakeholders in the small city. The case study consisted of two consecutive phases: a Foucauldian discourse analysis of GADRA’s annual reports between 2012 and 2021, followed by individual narrative interviews with 13 organisational members. An Africa(n)-centred community psychology orientation, revealed counter-discourse to the national “crisis in education” discourse surrounding the NGO. The discourse of crisis produced the legitimation for GADRA Education’s continued existence, action and embeddedness in Makhanda. The discourse of transformation informed their modes of support across primary, secondary and higher education. The discourse of access and participation constructed the NGO as a bridge and link between phases of education. The discourse of collaborative partnerships enabled solidarity between state and non-state actors towards educational change. Finally, the discourse of development positioned development at a grassroots level. These constellations formed GADRA Education’s counter-discourse, which produced the Organisation’s apparatus of resistance, formulated as situated praxis. The 5 organisational members’ narratives revealed the apparatus’s impacts on the subjectivities of youth in Makhanda in engendering hope and driving educational change in the city. In contrast to conceptions of education NGOs who work in the public schooling sector making little progress in dismantling educational inequity, this study illustrates the techniques of resistance leveraged, in the context of collaborative partnerships, by the local NGO. These techniques have wider applicability for education-development practitioners concerned with transformative change in their educational locales. It illustrates the principles and modes by which NGOs can operate in solidarity with the persistently marginalised majority, and thus contribute to shaping our imagined educational futures. I argue that psychology is a useful site to think about justice. Critical psychological theory can enable a deeper understanding of practice that contributes to impactful community organisation, intervention and resistance in the country’s education sector. The operationalisation of the values and principles of community psychology can make important contributions at the nexus of theory and practice in working towards educational, and ultimately social, change. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-10-11
A conspiracy of silence: the authorial potential of full masks in performer training, dramaturgy and audience perception in South African visual theatre
- Authors: Murray, Robert Ian
- Date: 2024-10-11
- Subjects: Liezl de Kock , People with disabilities and the performing arts , Experimental theater South Africa , Actors Training of , Theater for deaf people South Africa
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/467083 , vital:76813 , DOI https://doi.org/10.21504/10962/467083
- Description: Silent Mask Theatre in South Africa has the potential to cut across linguistic divides and deliver a product that offers an intimate, unique experience for the audience as well as the actor. South Africa not only has a complicated history, but also 11 languages (12 if one counts South African Sign Language – SASL -, which still holds a curious position of being counted official or not), and the one that theatre-makers choose to present in gives a certain “authority” to the production. Silent masks remove the need for linguistic understanding, something necessary for more abstract thought, and focusses instead on the emotional relevance and interplay between characters. In doing so, it proves an important way to create relevance for an audience, creating a delicate dance between the Mask (character and thereby text), how the actor plays it, and then the closing of meaning through the audience experience. Thus, is created a trialogue between these elements that gives the production the opportunity to speak to the hearts and minds of the audience. Globally, the study of silent character masks is still relatively new, with proponents of it only coming to the fore in the past few years (Wilsher, 2007). Mask Theatre has grown exponentially in the UK and Europe with companies like Vamos Theatre, exploring PTSD in works like A Brave Face (2018) or death in Dead Good (2021), and Familie Flöz either on the more whimsical side like Hotel Paradiso (2011) or the more hard-hitting Infinito (2006), gaining popularity and exposure. In South Africa, there is strangely not an indigenous tradition of masks, as opposed to other parts of Africa. This is fascinating, and probably points towards a more “oral tradition” of South Africa/Africa. However, the author aims to point out the ways that the silent mask entered South African consciousness at a time where more attention was being paid to “performing objects” (Proschan, 1985), and particularly in Cape Town with the advent of the Out the Box Festival. This thesis aims to contextualise Visual Theatre and Mask Theatre in a South African context, seeing within it a movement towards a more global perspective of puppetry, material performances, and performing objects. Although “ghettoised” for a long time (Taylor, 2004), performing objects emerged and became a leading case for the primal “text” of a performance. Handspring Puppet Company, Janni Younge, and the author’s company, FTH:K, became primary grounds of contestation against more conventional, text-based theatre. Starting with a reflective account of the author’s journey towards masks, the thesis branches out into a reflection on its author’s pedagogical praxis, and how silent masks work, before critically reflecting on and analysing his key works, such as Pictures of You (2008-2013), which deals with home invasions and grief, and Benchmarks (2011), which deals with the wave of xenophobia that hit South Africa around that time. . This were built from the ground up, working with current issues both in the author’s, and the country’s, mileau. In the last two decades, performing object work in South Africa has begun to flourish. This is the first thesis to investigate mask work in the country during this period. Its possibilities for Screen and Stage Acting are still being explored. , Thesis (PhD) -- Faculty of Humanities, Drama, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Murray, Robert Ian
- Date: 2024-10-11
- Subjects: Liezl de Kock , People with disabilities and the performing arts , Experimental theater South Africa , Actors Training of , Theater for deaf people South Africa
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/467083 , vital:76813 , DOI https://doi.org/10.21504/10962/467083
- Description: Silent Mask Theatre in South Africa has the potential to cut across linguistic divides and deliver a product that offers an intimate, unique experience for the audience as well as the actor. South Africa not only has a complicated history, but also 11 languages (12 if one counts South African Sign Language – SASL -, which still holds a curious position of being counted official or not), and the one that theatre-makers choose to present in gives a certain “authority” to the production. Silent masks remove the need for linguistic understanding, something necessary for more abstract thought, and focusses instead on the emotional relevance and interplay between characters. In doing so, it proves an important way to create relevance for an audience, creating a delicate dance between the Mask (character and thereby text), how the actor plays it, and then the closing of meaning through the audience experience. Thus, is created a trialogue between these elements that gives the production the opportunity to speak to the hearts and minds of the audience. Globally, the study of silent character masks is still relatively new, with proponents of it only coming to the fore in the past few years (Wilsher, 2007). Mask Theatre has grown exponentially in the UK and Europe with companies like Vamos Theatre, exploring PTSD in works like A Brave Face (2018) or death in Dead Good (2021), and Familie Flöz either on the more whimsical side like Hotel Paradiso (2011) or the more hard-hitting Infinito (2006), gaining popularity and exposure. In South Africa, there is strangely not an indigenous tradition of masks, as opposed to other parts of Africa. This is fascinating, and probably points towards a more “oral tradition” of South Africa/Africa. However, the author aims to point out the ways that the silent mask entered South African consciousness at a time where more attention was being paid to “performing objects” (Proschan, 1985), and particularly in Cape Town with the advent of the Out the Box Festival. This thesis aims to contextualise Visual Theatre and Mask Theatre in a South African context, seeing within it a movement towards a more global perspective of puppetry, material performances, and performing objects. Although “ghettoised” for a long time (Taylor, 2004), performing objects emerged and became a leading case for the primal “text” of a performance. Handspring Puppet Company, Janni Younge, and the author’s company, FTH:K, became primary grounds of contestation against more conventional, text-based theatre. Starting with a reflective account of the author’s journey towards masks, the thesis branches out into a reflection on its author’s pedagogical praxis, and how silent masks work, before critically reflecting on and analysing his key works, such as Pictures of You (2008-2013), which deals with home invasions and grief, and Benchmarks (2011), which deals with the wave of xenophobia that hit South Africa around that time. . This were built from the ground up, working with current issues both in the author’s, and the country’s, mileau. In the last two decades, performing object work in South Africa has begun to flourish. This is the first thesis to investigate mask work in the country during this period. Its possibilities for Screen and Stage Acting are still being explored. , Thesis (PhD) -- Faculty of Humanities, Drama, 2024
- Full Text:
- Date Issued: 2024-10-11
A content analysis of the framing and representation of Black Lives Matter protests by South African mainstream media
- Authors: Manyike, Lerato Gladys
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465799 , vital:76654
- Description: This study conducted a detailed analysis of 277 headlines using content analysis, focusing on how News24 portrays racial protests, particularly within the Black Lives Matter (BLM) movement. It explored News24's coverage of BLM protests from March to December 2020, uncovering various framing strategies and language nuances in news headlines. The research aimed to identify thematic frames, linguistic patterns, and overall media framing of BLM protests. The findings highlighted different framing strategies, including legitimising, conflict, and delegitimizing frames, along with the impact of descriptive language on audience perceptions. The study concluded that media framing is dynamic, responding to evolving events and public discourse, and provided recommendations for media transparency, diversity in newsrooms, media literacy, and ethical reporting. Future research suggestions include comparative analyses, audience reception studies, and policy impact assessments to deepen understanding and inform strategic interventions in media representations and public discourse on racial justice. Overall, the study contributes valuable insights into media framing practices and their impact on societal perceptions of racial justice issues. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Manyike, Lerato Gladys
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465799 , vital:76654
- Description: This study conducted a detailed analysis of 277 headlines using content analysis, focusing on how News24 portrays racial protests, particularly within the Black Lives Matter (BLM) movement. It explored News24's coverage of BLM protests from March to December 2020, uncovering various framing strategies and language nuances in news headlines. The research aimed to identify thematic frames, linguistic patterns, and overall media framing of BLM protests. The findings highlighted different framing strategies, including legitimising, conflict, and delegitimizing frames, along with the impact of descriptive language on audience perceptions. The study concluded that media framing is dynamic, responding to evolving events and public discourse, and provided recommendations for media transparency, diversity in newsrooms, media literacy, and ethical reporting. Future research suggestions include comparative analyses, audience reception studies, and policy impact assessments to deepen understanding and inform strategic interventions in media representations and public discourse on racial justice. Overall, the study contributes valuable insights into media framing practices and their impact on societal perceptions of racial justice issues. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-10-11
A decision support tool for equitable and sustainable water management in the Koue Bokkeveld
- Authors: Tholanah, Rodney
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464344 , vital:76503
- Description: Water is an important natural resource with multiple domestic and industrial uses. South Africa has a water scarcity problem, with domestic and industrial demand projected to increase due to population growth. One affected area is the Koue Bokkeveld (KBV), an agricultural catchment in the Western Cape. Water scarcity, especially in the summer, can cause conflicts among the farmers. This study sought to determine the extent to which Agent-Based (AB) modelling could be used to model the KBV catchment area and simulate future climate and usage scenarios. The study used the ComMod methodology as it allows stakeholders to be involved at each step of the modelling process, thus improving the model’s credibility as a decision-support tool (DST). The model was implemented using Cormas, an Agent-Based Model (ABM) implementation framework built with the Smalltalk language. The model was verified and validated through consultations with the catchment coordinator and through workshops with stakeholders. The ABM reflected the catchment characteristics. Farms known to have water shortages had water shortages in the ABM. However, there was one that did not have shortages, which is attributed to land use change. The ABM was used to run multiple simulation scenarios, and it provides simulation results at the crop field, farm and catchment levels, which allows the ABM to be used as a bottom-up DST. , Thesis (MSc) -- Faculty of Science, Computer Science, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Tholanah, Rodney
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464344 , vital:76503
- Description: Water is an important natural resource with multiple domestic and industrial uses. South Africa has a water scarcity problem, with domestic and industrial demand projected to increase due to population growth. One affected area is the Koue Bokkeveld (KBV), an agricultural catchment in the Western Cape. Water scarcity, especially in the summer, can cause conflicts among the farmers. This study sought to determine the extent to which Agent-Based (AB) modelling could be used to model the KBV catchment area and simulate future climate and usage scenarios. The study used the ComMod methodology as it allows stakeholders to be involved at each step of the modelling process, thus improving the model’s credibility as a decision-support tool (DST). The model was implemented using Cormas, an Agent-Based Model (ABM) implementation framework built with the Smalltalk language. The model was verified and validated through consultations with the catchment coordinator and through workshops with stakeholders. The ABM reflected the catchment characteristics. Farms known to have water shortages had water shortages in the ABM. However, there was one that did not have shortages, which is attributed to land use change. The ABM was used to run multiple simulation scenarios, and it provides simulation results at the crop field, farm and catchment levels, which allows the ABM to be used as a bottom-up DST. , Thesis (MSc) -- Faculty of Science, Computer Science, 2024
- Full Text:
- Date Issued: 2024-10-11
A descriptive study of lead arm muscle activation patterns during cricket batting
- Authors: McCarthy, Ryan Aidan
- Date: 2024-10-11
- Subjects: Cricket Batting , Muscle contraction , Elbow , Wrist , Forearm , Cricket players , School sports
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464754 , vital:76542
- Description: Introduction: Kinematic studies identify elbow extension and wrist flexion as key movements for bat swinging speed during cricket batting. Knowledge of lead arm muscle activation during cricket batting may provide a greater understanding of the mechanics leading to the generation of faster bat speed. Aim: The current investigation aimed to determine selected muscle activation of cricketer's lead arm, maximum bat swinging speed and angular separation of the pelvis and thorax in the transverse plane (known as the X-angle) during a distance-hitting batting protocol. Materials and Methods: 12 cricket players playing for a South African school 1st XI school team aged 16-19 years completed a distance-hitting batting protocol. Due to issues in data recording two participants' data was excluded leading to 10 participants being kept in the final analyses.Participants attempted to hit straight lofted drives while facing full-length deliveries at 80-100 km.h-1 from a bowling machine. Each participant faced 12-24 balls split into overs while lead arm muscle activation, bat speed, and angle of lead-elbow flexion were recorded. Each participant's elbow and wrist flexors and extensors were monitored by electromyography (EMG) units while they batted. The EMG units were placed on the wrist flexor and extensor origins and on Triceps and Biceps Brachii. Muscle activation for each muscle was recorded in millivolts (mv) and divided by the maximum measurement of voluntary muscle activation to determine the percentage of maximum voluntary contraction (%MVC) during each shot. Percentage MVC for batting phases of backlift, downswing, contact and follow-through were averaged to compare average %MVC per muscle across all batters and obtain inter-participant variability. Lead arm elbow angle and the %MVC of the elbow and wrist muscles will be compared between successful and unsuccessful shots for analysis. Each participant's lead arm elbow angle was monitored in degrees of flexion by a goniometer placed across the anterior aspect of the elbow joint. Due to the data not having a normal distribution, non-parametric tests were used to establish the variance between dependent variables. To determine the effect of multiple groups on the independent variables a Kruskal-Wallis test for ANOVA was used. Where significant differences were identified, multiple pairwise comparisons were completed to determine where the differences occurred. Results: Successful Lofted straight drives (32 shots) were compared to unsuccessful shots (101 shots) across all participants. Participants and batting phase were found to be significantly different for lead arm elbow angle and muscle activation however shot type was not found to be significantly different. Meaning that lead arm elbow angle and muscle activation differ based on the participant observed or based on the batting phase observed. The backswing phase recorded a higher amount of elbow flexion (155.25°) for Lofted straight drive compared to unsuccessful shots (157.86°) and lower activation across all muscles for Lofted straight drive. The lofted straight drive had a higher amount of elbow flexion (129.52°) compared to unsuccessful shots (149.24°) for the downswing phase and muscle activation was similar with greater variation for unsuccessful shots. At contact Lofted straight drive had a higher amount of elbow flexion (153.44° v 160.13°), and higher activation in the Biceps brachii (34.61% v 28.41%) and Triceps brachii (51.07% v 43.02%). For the follow-through phase Lofted straight drives had a higher amount of elbow flexion (144.87° v 149.59°) and greater Forearm extensor activation (37.13% v 31.28%). There was a large variation across all phases (coefitient of variation between 8.79%-70.28%) with backswing having the least variation and contact having the greatest. Meaning that the backswing phase is fairly predictable for batters and the contact phase is highly variable. Conclusion: Muscle activation increased in the last few milliseconds before contact. The Forearm extensor had the greatest activation during the backswing and follow-through phases. During the downswing phase, Forearm flexors had the greatest activation and at contact, the Triceps brachii had the greatest activation. This study emphasizes the importance of forearm and elbow muscle for batting. Appropriate strengthening of the muscles could also help a batter execute a powerful lofted drive. Future studies with objective measures linked to batting success in prior studies can build on the importance of these findings for batter success. This study provides insight into individual batter techniques and identifies important topics for future research. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: McCarthy, Ryan Aidan
- Date: 2024-10-11
- Subjects: Cricket Batting , Muscle contraction , Elbow , Wrist , Forearm , Cricket players , School sports
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464754 , vital:76542
- Description: Introduction: Kinematic studies identify elbow extension and wrist flexion as key movements for bat swinging speed during cricket batting. Knowledge of lead arm muscle activation during cricket batting may provide a greater understanding of the mechanics leading to the generation of faster bat speed. Aim: The current investigation aimed to determine selected muscle activation of cricketer's lead arm, maximum bat swinging speed and angular separation of the pelvis and thorax in the transverse plane (known as the X-angle) during a distance-hitting batting protocol. Materials and Methods: 12 cricket players playing for a South African school 1st XI school team aged 16-19 years completed a distance-hitting batting protocol. Due to issues in data recording two participants' data was excluded leading to 10 participants being kept in the final analyses.Participants attempted to hit straight lofted drives while facing full-length deliveries at 80-100 km.h-1 from a bowling machine. Each participant faced 12-24 balls split into overs while lead arm muscle activation, bat speed, and angle of lead-elbow flexion were recorded. Each participant's elbow and wrist flexors and extensors were monitored by electromyography (EMG) units while they batted. The EMG units were placed on the wrist flexor and extensor origins and on Triceps and Biceps Brachii. Muscle activation for each muscle was recorded in millivolts (mv) and divided by the maximum measurement of voluntary muscle activation to determine the percentage of maximum voluntary contraction (%MVC) during each shot. Percentage MVC for batting phases of backlift, downswing, contact and follow-through were averaged to compare average %MVC per muscle across all batters and obtain inter-participant variability. Lead arm elbow angle and the %MVC of the elbow and wrist muscles will be compared between successful and unsuccessful shots for analysis. Each participant's lead arm elbow angle was monitored in degrees of flexion by a goniometer placed across the anterior aspect of the elbow joint. Due to the data not having a normal distribution, non-parametric tests were used to establish the variance between dependent variables. To determine the effect of multiple groups on the independent variables a Kruskal-Wallis test for ANOVA was used. Where significant differences were identified, multiple pairwise comparisons were completed to determine where the differences occurred. Results: Successful Lofted straight drives (32 shots) were compared to unsuccessful shots (101 shots) across all participants. Participants and batting phase were found to be significantly different for lead arm elbow angle and muscle activation however shot type was not found to be significantly different. Meaning that lead arm elbow angle and muscle activation differ based on the participant observed or based on the batting phase observed. The backswing phase recorded a higher amount of elbow flexion (155.25°) for Lofted straight drive compared to unsuccessful shots (157.86°) and lower activation across all muscles for Lofted straight drive. The lofted straight drive had a higher amount of elbow flexion (129.52°) compared to unsuccessful shots (149.24°) for the downswing phase and muscle activation was similar with greater variation for unsuccessful shots. At contact Lofted straight drive had a higher amount of elbow flexion (153.44° v 160.13°), and higher activation in the Biceps brachii (34.61% v 28.41%) and Triceps brachii (51.07% v 43.02%). For the follow-through phase Lofted straight drives had a higher amount of elbow flexion (144.87° v 149.59°) and greater Forearm extensor activation (37.13% v 31.28%). There was a large variation across all phases (coefitient of variation between 8.79%-70.28%) with backswing having the least variation and contact having the greatest. Meaning that the backswing phase is fairly predictable for batters and the contact phase is highly variable. Conclusion: Muscle activation increased in the last few milliseconds before contact. The Forearm extensor had the greatest activation during the backswing and follow-through phases. During the downswing phase, Forearm flexors had the greatest activation and at contact, the Triceps brachii had the greatest activation. This study emphasizes the importance of forearm and elbow muscle for batting. Appropriate strengthening of the muscles could also help a batter execute a powerful lofted drive. Future studies with objective measures linked to batting success in prior studies can build on the importance of these findings for batter success. This study provides insight into individual batter techniques and identifies important topics for future research. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2024
- Full Text:
- Date Issued: 2024-10-11
A house accursed: reconsidering Sophocles’ sisters, Antigone & Ismene
- Authors: Fox, Peta Ann , Sophocles
- Date: 2024-10-11
- Subjects: Ismene (Greek mythology) , Antigone (Greek mythological figure) , Electra (Greek mythological figure) , Chrysothemis , Greek tragedy , Sisters in literature
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/467028 , vital:76808 , DOI https://doi.org/10.21504/10962/467028
- Description: Traditionally, Ismene’s refusal to help Antigone bury their brother in Sophocles’ Antigone tends to be regarded only in relation to Antigone’s own remarkable bravery. Antigone exists on the heroic level, Ismene on the ordinary; Antigone is courageous, Ismene is timid and submissive; Antigone is an idealist and an individualist, Ismene is convention and herd-bound. Ismene is, in many ways, presented as the antithesis of Antigone and Sophocles does indeed make use of her character as a foil to Antigone, but this thesis will argue that the relation between the two sisters is far more complicated than a dichotomous contrast between ‘extraordinary heroine’ and ‘average woman’. Like Antigone, Ismene is very much a character in her own right, and her emotions, motivations and impulses are every bit as realised and compelling as Antigone’s own. Both sisters have been deeply affected by the tragic misfortunes of their family, but their sad history affects each sister quite differently. Whereas Antigone’s instinctive reaction to Creon’s edict is a furious determination not to tolerate any further dishonour, Ismene’s equally instinctive reaction is to avoid the pattern of self-destructive inwardness that has plagued their family for generations. By offering a comprehensive re-examination of the key passages that have informed our critical reception of Ismene and the nature of her relationship with Antigone, this study aims to disrupt the established, and largely prejudiced, reading of Ismene as a model of feminine timidity and submission. Although Ismene is certainly no grand tragic heroine, titling the theoretical focus away from the death-oriented extremism of Antigone towards a more balanced consideration of the so-called ‘weaker sister’ not only allows for new insights into the nature of Sophoclean tragedy, but also challenges the very basis on which Ismene has so often been dismissed in favour of her more intrepid sister: the pervasive assumption that Sophocles has only given us one sister who is willing to risk her life for a principle. , Thesis (PhD) -- Faculty of Humanities, School of Languages and Literatures, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Fox, Peta Ann , Sophocles
- Date: 2024-10-11
- Subjects: Ismene (Greek mythology) , Antigone (Greek mythological figure) , Electra (Greek mythological figure) , Chrysothemis , Greek tragedy , Sisters in literature
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/467028 , vital:76808 , DOI https://doi.org/10.21504/10962/467028
- Description: Traditionally, Ismene’s refusal to help Antigone bury their brother in Sophocles’ Antigone tends to be regarded only in relation to Antigone’s own remarkable bravery. Antigone exists on the heroic level, Ismene on the ordinary; Antigone is courageous, Ismene is timid and submissive; Antigone is an idealist and an individualist, Ismene is convention and herd-bound. Ismene is, in many ways, presented as the antithesis of Antigone and Sophocles does indeed make use of her character as a foil to Antigone, but this thesis will argue that the relation between the two sisters is far more complicated than a dichotomous contrast between ‘extraordinary heroine’ and ‘average woman’. Like Antigone, Ismene is very much a character in her own right, and her emotions, motivations and impulses are every bit as realised and compelling as Antigone’s own. Both sisters have been deeply affected by the tragic misfortunes of their family, but their sad history affects each sister quite differently. Whereas Antigone’s instinctive reaction to Creon’s edict is a furious determination not to tolerate any further dishonour, Ismene’s equally instinctive reaction is to avoid the pattern of self-destructive inwardness that has plagued their family for generations. By offering a comprehensive re-examination of the key passages that have informed our critical reception of Ismene and the nature of her relationship with Antigone, this study aims to disrupt the established, and largely prejudiced, reading of Ismene as a model of feminine timidity and submission. Although Ismene is certainly no grand tragic heroine, titling the theoretical focus away from the death-oriented extremism of Antigone towards a more balanced consideration of the so-called ‘weaker sister’ not only allows for new insights into the nature of Sophoclean tragedy, but also challenges the very basis on which Ismene has so often been dismissed in favour of her more intrepid sister: the pervasive assumption that Sophocles has only given us one sister who is willing to risk her life for a principle. , Thesis (PhD) -- Faculty of Humanities, School of Languages and Literatures, 2024
- Full Text:
- Date Issued: 2024-10-11
A mechanistic and trait-based approach to investigating macroinvertebrates distribution and exposure to microplastics in riverine systems
- Authors: Owowenu, Enahoro Kennedy
- Date: 2024-10-11
- Subjects: Microplastics Environmental aspects , Water quality biological assessment , Hydrodynamics , Hydrogeomorphology , Biotope , Flow type
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466666 , vital:76765 , DOI https://doi.org/10.21504/10962/466666
- Description: Microplastics in rivers pose an ecological risk. Hydraulic biotopes form distinct flow patches that vary longitudinally along the river, potentially influencing the transport dynamics of microplastics. Macroinvertebrates exhibit adaptations to different hydraulic biotopes through their unique traits. These traits can mediate their exposure to microplastics, thereby imposing selective pressures on these organisms. Different taxa often demonstrate preferences for specific hydraulic biotopes characterized by distinct flow regimes. Understanding the transport dynamics of microplastics mediated by hydraulic biotopes and the potential exposure of macroinvertebrates at the hydraulic biotope scale is important for determining the fate of riverine microplastics and detecting species at risk. Both empirical and theoretical studies have highlighted the interconnectedness of hydrology, geomorphology, and microplastic transport in rivers, yet, there remains a gap in understanding how a hydro-geomorphological approach could enhance the understanding of the microplastic transport process. Little is known about the role of traits in driving macroinvertebrate exposure to microplastics at a scale relevant to ecological dynamics. This study addressed these gaps by applying a hydro-geomorphological approach to investigate the distribution of microplastics at the hydraulic biotope scale and assessed the potential exposure of macroinvertebrates using a trait-based approach. This study also explored the relationship between microplastic abundance and selected water physicochemical properties, as well as the influence of adjacent land use types. By integrating these aspects the research provided a comprehensive understanding of microplastics dynamics in river systems, shedding light on both environmental factors shaping their distribution and the potential impacts on aquatic organisms. The study was conducted over the wet and dry seasons (October 2021 – July 2022) at 10 sites located in the upper, middle, and lower reaches of the Swartkops and Buffalo River systems in the Eastern Cape Province of South Africa. The hydraulic biotopes (i.e., pools, runs, riffles) were grouped into two conceptualised forms, namely, sink and flush hydraulic zones and were characterized by hydraulic indices such as the Froude number and the Reynolds number. The flush hydraulic zone represents hydraulic biotopes where microplastics can potentially be remobilized quickly into suspension, and the sink represents biotopes where microplastics can potentially accumulate and remobilisation is far slower. Fast-to-moderate flowing hydraulic biotopes were conceptualised as microplastics flush zones while slow-flowing to still biotopes as microplastic sink zones. Samples were collected at different depths in each hydraulic zone to quantify suspended and settled forms of microplastics. Microplastics targeted in this study ranged in size from 0.063 mm to less than 5 mm. Classification was achieved through microscopic observation, and confirmation via Fourier Transform Infrared Spectroscopy (FTIR-ATR) was conducted for samples ranging from 0.5 mm to less than 5 mm. At the site level, settled microplastics showed statistically significant spatial and temporal variations between the sites, and between the seasons (P < 0.05). The suspended microplastic varied only spatially. Fibres and fragments were the dominant microplastic shape, while polyethylene and polypropylene were the dominant microplastic polymers. Suspended microplastics showed statistically significant variation between urban land cover and other land cover categories (industrial, agricultural, rural, and natural land cover). Microplastics abundance was associated with high levels of turbidity, total suspended solids, total inorganic nitrogen, higher temperatures and increasing electrical conductivity. At the hydraulic biotope scale, the mean occurrence of suspended microplastics (1.76 ± 1.44 items/L; mean + SD) in the flush hydraulic zone was higher than that in the sink zone (1.54 ± 1.46 items/L), while settled microplastics were more abundant in the sink hydraulic zone (1.82 ± 1.98 items/L) than the flush hydraulic zone (1.32 ± 1.49 items/L). This observation was in line with the prediction in this study. The mean suspended and settled microplastics concentrations were higher during the wet season across the flush and sink hydraulic zones than in the dry season. Global multivariate analysis of variance (MANOVA) and two-way analysis of variance (ANOVA) revealed significant spatial and temporal variations in settled microplastics abundances between the flush and sink hydraulic zones. The results indicated that geomorphologically defined units such as riffles and moderate to fast runs (flush) generally contained lower amounts of settled microplastics compared to pools and backwaters (sink). However, this distinction between the flush and sink microplastic zones was observed only for settled microplastics and not for suspended microplastics. Suspended and settled microplastics showed a statistically significant relationship with the Froude number index. The generalised additive model indicated that settled microplastics abundance distribution decreased significantly with increasing Froude number value in the flush zone. Suspended microplastics decreased at low Froude number values and showed an increasing trend at higher Froude number values of about 0.75. The results indicate the usefulness of the hydraulic biotope scale microplastic monitoring approach in detecting microplastic hotspots and explaining variations in microplastics abundances driven by instream hydraulics. Four traits and ecological preferences of macroinvertebrates including body size, gill type, feeding habit, and velocity preferences were selected and resolved into 17 trait attributes. The sink hydraulic zones such as pools were indicated to favour exposure to and ingestion of microplastics compared to the flush zones such as riffles and fast runs. Large body size macroinvertebrates were associated with the sink zone. Taxa with a very small body size had a higher likelihood for microplastics ingestion than taxa with other body sizes. Collectorgathering macroinvertebrates taxa that have operculate gills with small body sizes were more prone to exposure to microplastics in hydraulic biotopes with slow to very slow velocities. Fibres were the most abundant plastic ingested by macroinvertebrates preferring the flush zone while fibres and fragments were mostly ingested by those preferring the sink zones. The binomial logistic model revealed a highly significant result for the likelihood of operculate gill shape to clog in the sink hydraulic zone. The result of the binomial logistic regression indicates the usefulness of the trait-based approach for predicting exposure to microplastics. Overall, the study reveals the influences of hydro-geomorphological features on the transport dynamics of microplastics and the usefulness of the trait-based approach in the ecological study of microplastics in riverine systems. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Owowenu, Enahoro Kennedy
- Date: 2024-10-11
- Subjects: Microplastics Environmental aspects , Water quality biological assessment , Hydrodynamics , Hydrogeomorphology , Biotope , Flow type
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466666 , vital:76765 , DOI https://doi.org/10.21504/10962/466666
- Description: Microplastics in rivers pose an ecological risk. Hydraulic biotopes form distinct flow patches that vary longitudinally along the river, potentially influencing the transport dynamics of microplastics. Macroinvertebrates exhibit adaptations to different hydraulic biotopes through their unique traits. These traits can mediate their exposure to microplastics, thereby imposing selective pressures on these organisms. Different taxa often demonstrate preferences for specific hydraulic biotopes characterized by distinct flow regimes. Understanding the transport dynamics of microplastics mediated by hydraulic biotopes and the potential exposure of macroinvertebrates at the hydraulic biotope scale is important for determining the fate of riverine microplastics and detecting species at risk. Both empirical and theoretical studies have highlighted the interconnectedness of hydrology, geomorphology, and microplastic transport in rivers, yet, there remains a gap in understanding how a hydro-geomorphological approach could enhance the understanding of the microplastic transport process. Little is known about the role of traits in driving macroinvertebrate exposure to microplastics at a scale relevant to ecological dynamics. This study addressed these gaps by applying a hydro-geomorphological approach to investigate the distribution of microplastics at the hydraulic biotope scale and assessed the potential exposure of macroinvertebrates using a trait-based approach. This study also explored the relationship between microplastic abundance and selected water physicochemical properties, as well as the influence of adjacent land use types. By integrating these aspects the research provided a comprehensive understanding of microplastics dynamics in river systems, shedding light on both environmental factors shaping their distribution and the potential impacts on aquatic organisms. The study was conducted over the wet and dry seasons (October 2021 – July 2022) at 10 sites located in the upper, middle, and lower reaches of the Swartkops and Buffalo River systems in the Eastern Cape Province of South Africa. The hydraulic biotopes (i.e., pools, runs, riffles) were grouped into two conceptualised forms, namely, sink and flush hydraulic zones and were characterized by hydraulic indices such as the Froude number and the Reynolds number. The flush hydraulic zone represents hydraulic biotopes where microplastics can potentially be remobilized quickly into suspension, and the sink represents biotopes where microplastics can potentially accumulate and remobilisation is far slower. Fast-to-moderate flowing hydraulic biotopes were conceptualised as microplastics flush zones while slow-flowing to still biotopes as microplastic sink zones. Samples were collected at different depths in each hydraulic zone to quantify suspended and settled forms of microplastics. Microplastics targeted in this study ranged in size from 0.063 mm to less than 5 mm. Classification was achieved through microscopic observation, and confirmation via Fourier Transform Infrared Spectroscopy (FTIR-ATR) was conducted for samples ranging from 0.5 mm to less than 5 mm. At the site level, settled microplastics showed statistically significant spatial and temporal variations between the sites, and between the seasons (P < 0.05). The suspended microplastic varied only spatially. Fibres and fragments were the dominant microplastic shape, while polyethylene and polypropylene were the dominant microplastic polymers. Suspended microplastics showed statistically significant variation between urban land cover and other land cover categories (industrial, agricultural, rural, and natural land cover). Microplastics abundance was associated with high levels of turbidity, total suspended solids, total inorganic nitrogen, higher temperatures and increasing electrical conductivity. At the hydraulic biotope scale, the mean occurrence of suspended microplastics (1.76 ± 1.44 items/L; mean + SD) in the flush hydraulic zone was higher than that in the sink zone (1.54 ± 1.46 items/L), while settled microplastics were more abundant in the sink hydraulic zone (1.82 ± 1.98 items/L) than the flush hydraulic zone (1.32 ± 1.49 items/L). This observation was in line with the prediction in this study. The mean suspended and settled microplastics concentrations were higher during the wet season across the flush and sink hydraulic zones than in the dry season. Global multivariate analysis of variance (MANOVA) and two-way analysis of variance (ANOVA) revealed significant spatial and temporal variations in settled microplastics abundances between the flush and sink hydraulic zones. The results indicated that geomorphologically defined units such as riffles and moderate to fast runs (flush) generally contained lower amounts of settled microplastics compared to pools and backwaters (sink). However, this distinction between the flush and sink microplastic zones was observed only for settled microplastics and not for suspended microplastics. Suspended and settled microplastics showed a statistically significant relationship with the Froude number index. The generalised additive model indicated that settled microplastics abundance distribution decreased significantly with increasing Froude number value in the flush zone. Suspended microplastics decreased at low Froude number values and showed an increasing trend at higher Froude number values of about 0.75. The results indicate the usefulness of the hydraulic biotope scale microplastic monitoring approach in detecting microplastic hotspots and explaining variations in microplastics abundances driven by instream hydraulics. Four traits and ecological preferences of macroinvertebrates including body size, gill type, feeding habit, and velocity preferences were selected and resolved into 17 trait attributes. The sink hydraulic zones such as pools were indicated to favour exposure to and ingestion of microplastics compared to the flush zones such as riffles and fast runs. Large body size macroinvertebrates were associated with the sink zone. Taxa with a very small body size had a higher likelihood for microplastics ingestion than taxa with other body sizes. Collectorgathering macroinvertebrates taxa that have operculate gills with small body sizes were more prone to exposure to microplastics in hydraulic biotopes with slow to very slow velocities. Fibres were the most abundant plastic ingested by macroinvertebrates preferring the flush zone while fibres and fragments were mostly ingested by those preferring the sink zones. The binomial logistic model revealed a highly significant result for the likelihood of operculate gill shape to clog in the sink hydraulic zone. The result of the binomial logistic regression indicates the usefulness of the trait-based approach for predicting exposure to microplastics. Overall, the study reveals the influences of hydro-geomorphological features on the transport dynamics of microplastics and the usefulness of the trait-based approach in the ecological study of microplastics in riverine systems. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2024
- Full Text:
- Date Issued: 2024-10-11
A review of African praying mantises (Dictyoptera: Mantodea) incorporating molecular and morphological data
- Authors: Roestof, Bruce
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464428 , vital:76510
- Description: Praying mantises (Dictyoptera: Mantodea) are an iconic group of predatory insects, comprising around 2500 species globally, that occur in all zoogeographic regions except the poles. Their presence in the social psyche of many cultures has existed for millennia, but until the past decade, Mantodea has received little attention from the scientific community as the constituent species are of little economic or medical importance. Africa is rich in praying mantis diversity, accounting for approximately 45% of all described species, yet it remains largely under-sampled compared to the New World and Asian regions. Recent exploration of Gabon and Central African Republic have proved fruitful, with new species descriptions being major highlights. A recent re-cataloguing of southern African praying mantises has proved useful as specimen identifications were checked, new distributions were recorded, and most importantly, it was revealed that museum collections have significantly more diversity than previously recorded. A meta-analysis of African praying mantises was conducted; we present a species checklist to the countries of Africa, including Madagascar and surrounding islands. Currently, 17 families, 182 genera, and 1104 species occur in Africa.Historically, the classification of praying mantises was based solely on morphological features, and the novelty of the field at the time made it unclear which characteristics were of taxonomic importance. The onset of molecular systematics brought attention to incongruences between morphological and molecular phylogenies, believed to be attributed to convergent evolution masking the underlying evolutionary processes that occurred. Significant progress has been made in the past two decades regarding Mantodean classification and most described genera have their phylogenetic position. With the addition of more African taxa, we present mantodean phylogenies for molecular and morphological data. Molecular phylogenies were estimated through Bayesian Inference and Maximum Likelihood analyses using two nuclear (28S and H3) and two mitochondrial markers (16S and COI) for 210 individuals that represented 24 of the 29 families globally. Morphological phylogenies were estimated through Maximum Likelihood analyses of a morphological data matrix comprising 149 characters for 248 individuals that represent 24 families. The same data matrix was used to produce a key to all African mantodean families, accompanied by their descriptions. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Roestof, Bruce
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464428 , vital:76510
- Description: Praying mantises (Dictyoptera: Mantodea) are an iconic group of predatory insects, comprising around 2500 species globally, that occur in all zoogeographic regions except the poles. Their presence in the social psyche of many cultures has existed for millennia, but until the past decade, Mantodea has received little attention from the scientific community as the constituent species are of little economic or medical importance. Africa is rich in praying mantis diversity, accounting for approximately 45% of all described species, yet it remains largely under-sampled compared to the New World and Asian regions. Recent exploration of Gabon and Central African Republic have proved fruitful, with new species descriptions being major highlights. A recent re-cataloguing of southern African praying mantises has proved useful as specimen identifications were checked, new distributions were recorded, and most importantly, it was revealed that museum collections have significantly more diversity than previously recorded. A meta-analysis of African praying mantises was conducted; we present a species checklist to the countries of Africa, including Madagascar and surrounding islands. Currently, 17 families, 182 genera, and 1104 species occur in Africa.Historically, the classification of praying mantises was based solely on morphological features, and the novelty of the field at the time made it unclear which characteristics were of taxonomic importance. The onset of molecular systematics brought attention to incongruences between morphological and molecular phylogenies, believed to be attributed to convergent evolution masking the underlying evolutionary processes that occurred. Significant progress has been made in the past two decades regarding Mantodean classification and most described genera have their phylogenetic position. With the addition of more African taxa, we present mantodean phylogenies for molecular and morphological data. Molecular phylogenies were estimated through Bayesian Inference and Maximum Likelihood analyses using two nuclear (28S and H3) and two mitochondrial markers (16S and COI) for 210 individuals that represented 24 of the 29 families globally. Morphological phylogenies were estimated through Maximum Likelihood analyses of a morphological data matrix comprising 149 characters for 248 individuals that represent 24 families. The same data matrix was used to produce a key to all African mantodean families, accompanied by their descriptions. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2024
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- Date Issued: 2024-10-11