Effect of a low density dust shell on the propagation of gravitational waves:
- Bishop, Nigel T, Van der Walt, Petrus J, Naidoo, Monos
- Authors: Bishop, Nigel T , Van der Walt, Petrus J , Naidoo, Monos
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159935 , vital:40357 , https://0-doi.org.wam.seals.ac.za/10.1007/s10714-020-02740-9
- Description: Using the Bondi-Sachs formalism, the problem of a gravitational wave source surrounded by a spherical dust shell is considered. Using linearized perturbation theory, the geometry is found in the regions: in the shell, exterior to the shell, and interior to the shell. It is found that the dust shell causes the gravitational wave to be modified both in magnitude and phase, but without any energy being transferred to or from the dust.
- Full Text:
- Date Issued: 2020
- Authors: Bishop, Nigel T , Van der Walt, Petrus J , Naidoo, Monos
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159935 , vital:40357 , https://0-doi.org.wam.seals.ac.za/10.1007/s10714-020-02740-9
- Description: Using the Bondi-Sachs formalism, the problem of a gravitational wave source surrounded by a spherical dust shell is considered. Using linearized perturbation theory, the geometry is found in the regions: in the shell, exterior to the shell, and interior to the shell. It is found that the dust shell causes the gravitational wave to be modified both in magnitude and phase, but without any energy being transferred to or from the dust.
- Full Text:
- Date Issued: 2020
Effect of drought on communal livestock farmers in KwaZulu-Natal, South Africa:
- Vetter, S, Goodall, V L, Alcock, R
- Authors: Vetter, S , Goodall, V L , Alcock, R
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179006 , vital:40105 , https://doi.org/10.2989/10220119.2020.1738552
- Description: Despite the size of the informal small-scale farming sector and its livestock holdings in South Africa, there has been little detailed work to assess how livestock populations are affected by drought. South Africa experienced a major drought in 2015–2016. We analysed goat and cattle census data from the Msinga area in KwaZulu-Natal, which represent the livestock of some 3 000 households. Cattle farmers in the study area lost 43% of the herd, compared with 29% for goats, in 2015–2016. Three years after the drought, cattle numbers remained depressed, whereas goat numbers had recovered. Larger herds suffered lower mortality rates, suggesting that owners of larger herds had better means to support their herds. Support to reduce drought losses and aid recovery should take into consideration the different capabilities and requirements of small and large herd owners. Effects of high stocking rates and resource condition on mortality and herd growth were apparent during the drought year of 2016, but not the other years. Most die-offs appear to have been concentrated in a short period once forage and water resources became too scarce and far to reach. Recognising when this threshold is imminent would be useful for targeting strategic interventions.
- Full Text:
- Date Issued: 2020
- Authors: Vetter, S , Goodall, V L , Alcock, R
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179006 , vital:40105 , https://doi.org/10.2989/10220119.2020.1738552
- Description: Despite the size of the informal small-scale farming sector and its livestock holdings in South Africa, there has been little detailed work to assess how livestock populations are affected by drought. South Africa experienced a major drought in 2015–2016. We analysed goat and cattle census data from the Msinga area in KwaZulu-Natal, which represent the livestock of some 3 000 households. Cattle farmers in the study area lost 43% of the herd, compared with 29% for goats, in 2015–2016. Three years after the drought, cattle numbers remained depressed, whereas goat numbers had recovered. Larger herds suffered lower mortality rates, suggesting that owners of larger herds had better means to support their herds. Support to reduce drought losses and aid recovery should take into consideration the different capabilities and requirements of small and large herd owners. Effects of high stocking rates and resource condition on mortality and herd growth were apparent during the drought year of 2016, but not the other years. Most die-offs appear to have been concentrated in a short period once forage and water resources became too scarce and far to reach. Recognising when this threshold is imminent would be useful for targeting strategic interventions.
- Full Text:
- Date Issued: 2020
Effect of increasing fossil shell flour levels on digestive and metabolic utilization, health, body weight change and wool production, and quality in Dohne-Merino wethers
- Authors: Ikusika, Olusegun Oyebade
- Date: 2020
- Subjects: Merino sheep Sheep -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/18465 , vital:42542
- Description: The study's broad objective was to assess growth performance, blood and parasitic profiles, wool parameters, methane emission, and nutritional status of Dohne-Merino wethers fed diets supplemented with varying levels of fossil shell flour. Twenty-four Dohne-Merino wethers, averagely weighing 20.0±1.50 kg, were divided into four groups and used in this study. The effects of varying inclusion levels of fossil shell flour (FSF) (0, 2, 4, and 6 %) on feed intake, water intake, nutrient digestibility, N-retention, hematobiochemical and parasitic profiles, body condition scores, feed preference, wool parameters and methane output were determined. The influence of FSF's varying inclusion levels on fermentation parameters, in vitro true digestibility, and relative feed values were also determined. Wethers fed with 4% FSF inclusion level diet showed the highest (P<0.05) values for dry matter intake, average daily weight gain, N retention, (Nitrogen retention) and apparent digestibility of crude protein (CP), Ether Extract (EE) and Ash 6 % (P < 0.05). The urinary N and fecal N were lowest in wethers fed 4% FSF inclusion level and highest in those fed on diets without FSF (P < 0.05). Water intake was highest in wethers fed 0% FSF diet, followed by those fed on 4% and lowest in 6% FSF (P< 0.05). There was a significant increase in white blood cell counts in wethers fed on a diet with 4% and 6% FSF inclusion levels from day 10 to 100 compared to wethers fed on a diet with 0% and 2% FSF (P <0.05). Red blood cell counts also increased significantly in wethers fed on a diet containing 4% FSF, but a slight increase in wethers with 6 % FSF diet, throughout the experimental period (P < 0.05). Blood urea was highest in wethers fed 0% FSF inclusion level and lowest in 6% at day 30 to day 100. Wethers on 4% FSF diet showed an increase in blood urea from day 30 to day 100 (P < 0.05) while wethers on 0% and 2% remained unchanged (P<0.05) during this period and not different (P > 0.05) from wethers on 4% FSF as well. The total protein concentration, albumin, total bilirubin, Na, K, glucose, cholesterol, and liver enzymes were normal for wethers. However, serum creatinine level was lower in wethers fed on 4% FSF than those on 0% FSF (P < 0.01). Haemonchus and Coccidian fecal egg counts were low in wethers fed diets with 2%, 4%, and 6 % FSF (P < 0.01) compared 11 with wethers fed with 0% FSF inclusion level during the same period. The body condition score of wethers fed on diets with 2%, 4%, and 6% FSF inclusion levels were higher than those on 0% (P < 0.05). Wool yield, staple length, the coefficient variation of the fibre diameter, and fibre of wethers fed on diets with FSF were higher than those without FSF (P < 0.05). The fibre diameter of the wethers fed on FSF supplemented diets was the same as those on 0 % FSF (P > 0.05). The wethers spent more time on FSF supplemented diets and consumed more feed compared to that without FSF supplemented (P < 0.05). The levels of FSF inclusion in the diet affected the enteric methane output (ppm-m), where 4 % FSF had the highest enteric methane output while wethers on 2 % FSF had the lowest methane output (P < 0.05). Resting wethers produced more methane (g/day) than those feeding or standing (P < 0.05). Increasing levels of FSF did not affect ruminal temperature and pH. Ammonia-N increased with increasing FSF except in wethers fed on a diet with 4% FSF (P < 0.01). The total molar concentrations of the wethers' volatile fatty acids decreased with increasing FSF levels (P > 0.05). The acetic propionic ratio of the wethers also decreased except at a 4% inclusion level. The in vitro true digestibility dry matter (IVTDDM), in vitro true digestibility neutral detergent fibre (IVTDNDF), and in vitro true digestibility acid detergent fibre (IVTDADF) of the wethers decreased up to 4% FSF inclusion but tended to increase at 6% inclusion. This study's result as one of the pioneer studies in Dohne-Marino wethers showed that FSF treatment has the potential to improve the nutritional status of the animal and the animal performance and wool quality. Health-wise, FSF decrease nematode population and boost animal immunity as seen in RBC and WBC counts. It also can play a major role in protecting the environment, as seen in its reduction in feacal and urinary nitrogen, which is heavily involved in environmental pollution. Result also confirmed that the best period to target for methane mitigation in ruminants is the resting period. In conclusion, the inclusion of FSF in the diet of Dohne-Merino wethers has the potential to improve the overall performance, with a 4% FSF inclusion level having optimal productivity. However, future research is required to investigate FSF's effect on meat quality, rumen microbial community, in-vivo digestibility, and milk production.
- Full Text:
- Date Issued: 2020
- Authors: Ikusika, Olusegun Oyebade
- Date: 2020
- Subjects: Merino sheep Sheep -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/18465 , vital:42542
- Description: The study's broad objective was to assess growth performance, blood and parasitic profiles, wool parameters, methane emission, and nutritional status of Dohne-Merino wethers fed diets supplemented with varying levels of fossil shell flour. Twenty-four Dohne-Merino wethers, averagely weighing 20.0±1.50 kg, were divided into four groups and used in this study. The effects of varying inclusion levels of fossil shell flour (FSF) (0, 2, 4, and 6 %) on feed intake, water intake, nutrient digestibility, N-retention, hematobiochemical and parasitic profiles, body condition scores, feed preference, wool parameters and methane output were determined. The influence of FSF's varying inclusion levels on fermentation parameters, in vitro true digestibility, and relative feed values were also determined. Wethers fed with 4% FSF inclusion level diet showed the highest (P<0.05) values for dry matter intake, average daily weight gain, N retention, (Nitrogen retention) and apparent digestibility of crude protein (CP), Ether Extract (EE) and Ash 6 % (P < 0.05). The urinary N and fecal N were lowest in wethers fed 4% FSF inclusion level and highest in those fed on diets without FSF (P < 0.05). Water intake was highest in wethers fed 0% FSF diet, followed by those fed on 4% and lowest in 6% FSF (P< 0.05). There was a significant increase in white blood cell counts in wethers fed on a diet with 4% and 6% FSF inclusion levels from day 10 to 100 compared to wethers fed on a diet with 0% and 2% FSF (P <0.05). Red blood cell counts also increased significantly in wethers fed on a diet containing 4% FSF, but a slight increase in wethers with 6 % FSF diet, throughout the experimental period (P < 0.05). Blood urea was highest in wethers fed 0% FSF inclusion level and lowest in 6% at day 30 to day 100. Wethers on 4% FSF diet showed an increase in blood urea from day 30 to day 100 (P < 0.05) while wethers on 0% and 2% remained unchanged (P<0.05) during this period and not different (P > 0.05) from wethers on 4% FSF as well. The total protein concentration, albumin, total bilirubin, Na, K, glucose, cholesterol, and liver enzymes were normal for wethers. However, serum creatinine level was lower in wethers fed on 4% FSF than those on 0% FSF (P < 0.01). Haemonchus and Coccidian fecal egg counts were low in wethers fed diets with 2%, 4%, and 6 % FSF (P < 0.01) compared 11 with wethers fed with 0% FSF inclusion level during the same period. The body condition score of wethers fed on diets with 2%, 4%, and 6% FSF inclusion levels were higher than those on 0% (P < 0.05). Wool yield, staple length, the coefficient variation of the fibre diameter, and fibre of wethers fed on diets with FSF were higher than those without FSF (P < 0.05). The fibre diameter of the wethers fed on FSF supplemented diets was the same as those on 0 % FSF (P > 0.05). The wethers spent more time on FSF supplemented diets and consumed more feed compared to that without FSF supplemented (P < 0.05). The levels of FSF inclusion in the diet affected the enteric methane output (ppm-m), where 4 % FSF had the highest enteric methane output while wethers on 2 % FSF had the lowest methane output (P < 0.05). Resting wethers produced more methane (g/day) than those feeding or standing (P < 0.05). Increasing levels of FSF did not affect ruminal temperature and pH. Ammonia-N increased with increasing FSF except in wethers fed on a diet with 4% FSF (P < 0.01). The total molar concentrations of the wethers' volatile fatty acids decreased with increasing FSF levels (P > 0.05). The acetic propionic ratio of the wethers also decreased except at a 4% inclusion level. The in vitro true digestibility dry matter (IVTDDM), in vitro true digestibility neutral detergent fibre (IVTDNDF), and in vitro true digestibility acid detergent fibre (IVTDADF) of the wethers decreased up to 4% FSF inclusion but tended to increase at 6% inclusion. This study's result as one of the pioneer studies in Dohne-Marino wethers showed that FSF treatment has the potential to improve the nutritional status of the animal and the animal performance and wool quality. Health-wise, FSF decrease nematode population and boost animal immunity as seen in RBC and WBC counts. It also can play a major role in protecting the environment, as seen in its reduction in feacal and urinary nitrogen, which is heavily involved in environmental pollution. Result also confirmed that the best period to target for methane mitigation in ruminants is the resting period. In conclusion, the inclusion of FSF in the diet of Dohne-Merino wethers has the potential to improve the overall performance, with a 4% FSF inclusion level having optimal productivity. However, future research is required to investigate FSF's effect on meat quality, rumen microbial community, in-vivo digestibility, and milk production.
- Full Text:
- Date Issued: 2020
Effect of the nature of nanoparticles on the photophysicochemical properties and photodynamic antimicrobial chemotherapy of phthalocyanines
- Authors: Magadla, Aviwe
- Date: 2020
- Subjects: Nanoparticles , Phthalocyanines , Anti-infective agents -- Therapeutic use , Photochemotherapy , Photochemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/123107 , vital:35406
- Description: In this work, the syntheses and characterisation of Zn monocaffeic acid tri–tert–butyl phthalocyanine (1), Zn monocarboxyphenoxy tri– tert–butylphenoxyl phthalocyanine (2), tetrakis phenoxy N,N-dimethyl-4-(methylimino) phthalocyanine indium (III) chloride (3) and tetrakis N,N-dimethyl-4-(methylimino) phthalocyanine indium (III) chloride (5) are presented. Complexes 3 and 5 were further quartenised with 1,3- propanesultone to form corresponding complexes (4) and (6), respectively. Complexes 1 and 2 were covalently linked to amino functionalised nanoparticles (NPs). Complexes 3, 4, 5 and 6 where linked to oleic acid/oleylamine capped (OLA/OLM) silver-iron dimers (Ag-Fe3O4 OLA/OLM) and silver-iron core shell (Ag@Fe3O4 OLA/OLM) NPs via interaction between the nanoparticles and the imino group on the phthalocyanines. The phthalocyanine-NP conjugates afforded an increase in triplet quantum yields with a corresponding decrease in fluorescence quantum yield as compared to the phthalocyanine complexes alone. Complexes 3, 4 and their conjugates were then used for photodynamic antimicrobial chemotherapy on E. coli. The zwitterionic photosensitiser 4 and its conjugates showed better efficiency for photodynamic antimicrobial chemotherapy compared to their neutral counterparts.
- Full Text:
- Date Issued: 2020
- Authors: Magadla, Aviwe
- Date: 2020
- Subjects: Nanoparticles , Phthalocyanines , Anti-infective agents -- Therapeutic use , Photochemotherapy , Photochemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/123107 , vital:35406
- Description: In this work, the syntheses and characterisation of Zn monocaffeic acid tri–tert–butyl phthalocyanine (1), Zn monocarboxyphenoxy tri– tert–butylphenoxyl phthalocyanine (2), tetrakis phenoxy N,N-dimethyl-4-(methylimino) phthalocyanine indium (III) chloride (3) and tetrakis N,N-dimethyl-4-(methylimino) phthalocyanine indium (III) chloride (5) are presented. Complexes 3 and 5 were further quartenised with 1,3- propanesultone to form corresponding complexes (4) and (6), respectively. Complexes 1 and 2 were covalently linked to amino functionalised nanoparticles (NPs). Complexes 3, 4, 5 and 6 where linked to oleic acid/oleylamine capped (OLA/OLM) silver-iron dimers (Ag-Fe3O4 OLA/OLM) and silver-iron core shell (Ag@Fe3O4 OLA/OLM) NPs via interaction between the nanoparticles and the imino group on the phthalocyanines. The phthalocyanine-NP conjugates afforded an increase in triplet quantum yields with a corresponding decrease in fluorescence quantum yield as compared to the phthalocyanine complexes alone. Complexes 3, 4 and their conjugates were then used for photodynamic antimicrobial chemotherapy on E. coli. The zwitterionic photosensitiser 4 and its conjugates showed better efficiency for photodynamic antimicrobial chemotherapy compared to their neutral counterparts.
- Full Text:
- Date Issued: 2020
Effectiveness of different interventions to reduce occupational sitting among office administrators at Rhodes University
- Authors: Malesa, Thato
- Date: 2020
- Subjects: Standing position , Sedentary behavior , Work environment , Employee health promotion , Office furniture -- Design , Industrial hygiene , Employees -- Health risk assessment , Human engineering , Compliance
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166403 , vital:41360
- Description: Background: Sitting for prolonged periods is common in the working environment. Office workers are exposed to long periods of sitting time at work. Research has reported associations between prolonged sitting and negative health implications. As such studies have proposed different interventions aimed at reducing sitting times in the workplace. The aim of the current study was to evaluate the effectiveness of two different interventions, physical intervention (sit-stand worktables) and personal intervention (instruction to stretch) on compliance and reducing occupational sitting behaviour. The study also aimed to investigate the effectiveness of interventions in improving or impairing mood. Methods: The study took the form of a fieldbased study atRhodes University, Makhanda, South Africa. Fifteen full–time office workers in different divisions participated in the study. Participants were randomly allocated to either the physical or personal intervention group. In both intervention groups, partic ipants were prompted to stand for five minutes every hour during the workday to either work in a standing position or perform stretches. Over the course of the experiment, desk occupancy, sitting/standing time and mood effect were recorded in both intervention groups Both intervention groups were monitored for a period of three months (58 days). Results: The study found that the physical intervention group was an effective approach to reduce prolonged sitting in the workplace in comparison to the personal intervention group. Over the course of the experiment, there was sustain usage of interventions in both groups, however, in the physical intervention group desk usage decreased overtime. The findings of the study also show that some participants were more compliant with the study procedures than others. It was also found that mood improved upon introducing interventions in the workplace. However, with the outcomes of the results, the study acknowledges that several factors emerged which are likely to impact compliance, which future studies may investigate. Conclusion: Although sit-stand worktables are expensive, it seems like introducing them was successful in reducing sitting time and changing sitting behaviour in comparison to an intervention that instruct s individuals to stand up and stretch.
- Full Text:
- Date Issued: 2020
- Authors: Malesa, Thato
- Date: 2020
- Subjects: Standing position , Sedentary behavior , Work environment , Employee health promotion , Office furniture -- Design , Industrial hygiene , Employees -- Health risk assessment , Human engineering , Compliance
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166403 , vital:41360
- Description: Background: Sitting for prolonged periods is common in the working environment. Office workers are exposed to long periods of sitting time at work. Research has reported associations between prolonged sitting and negative health implications. As such studies have proposed different interventions aimed at reducing sitting times in the workplace. The aim of the current study was to evaluate the effectiveness of two different interventions, physical intervention (sit-stand worktables) and personal intervention (instruction to stretch) on compliance and reducing occupational sitting behaviour. The study also aimed to investigate the effectiveness of interventions in improving or impairing mood. Methods: The study took the form of a fieldbased study atRhodes University, Makhanda, South Africa. Fifteen full–time office workers in different divisions participated in the study. Participants were randomly allocated to either the physical or personal intervention group. In both intervention groups, partic ipants were prompted to stand for five minutes every hour during the workday to either work in a standing position or perform stretches. Over the course of the experiment, desk occupancy, sitting/standing time and mood effect were recorded in both intervention groups Both intervention groups were monitored for a period of three months (58 days). Results: The study found that the physical intervention group was an effective approach to reduce prolonged sitting in the workplace in comparison to the personal intervention group. Over the course of the experiment, there was sustain usage of interventions in both groups, however, in the physical intervention group desk usage decreased overtime. The findings of the study also show that some participants were more compliant with the study procedures than others. It was also found that mood improved upon introducing interventions in the workplace. However, with the outcomes of the results, the study acknowledges that several factors emerged which are likely to impact compliance, which future studies may investigate. Conclusion: Although sit-stand worktables are expensive, it seems like introducing them was successful in reducing sitting time and changing sitting behaviour in comparison to an intervention that instruct s individuals to stand up and stretch.
- Full Text:
- Date Issued: 2020
Effectiveness of private land conservation areas in maintaining natural land cover and biodiversity intactness
- Shumba, Tafadzwa, de Vos, Alta, Biggs, Reinette, Esler, Karen J, Ament, Judith M, Clements, Hayley S
- Authors: Shumba, Tafadzwa , de Vos, Alta , Biggs, Reinette , Esler, Karen J , Ament, Judith M , Clements, Hayley S
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415852 , vital:71294 , xlink:href="https://doi.org/10.1016/j.gecco.2020.e00935"
- Description: Private land conservation areas (PLCAs) are increasingly looked to for meeting the deficit left by state-owned protected areas in reaching global conservation targets. However, despite the increasing extent and recognition of PLCAs as a complementary conservation strategy, little research has been done to quantify their effectiveness; a critical consideration if they are to be counted towards international biodiversity conservation targets. The long history of PLCAs in South Africa provides an interesting case study to address this knowledge gap. Here, we quantified the effectiveness of South African PLCAs by comparing losses in natural land cover and biodiversity intactness within PLCAs with different levels of protection to that of unprotected control points. Points within PLCAs were matched with unprotected control points to test the prediction that if PLCAs offer effective protection, losses in natural land cover and biodiversity intactness would be significantly lower within their boundaries in comparison to unprotected controls exposed to similar conditions. Consequences of natural land cover loss on biodiversity intactness were thus assessed, thus advancing standard approaches for quantifying effectiveness.
- Full Text:
- Date Issued: 2020
- Authors: Shumba, Tafadzwa , de Vos, Alta , Biggs, Reinette , Esler, Karen J , Ament, Judith M , Clements, Hayley S
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415852 , vital:71294 , xlink:href="https://doi.org/10.1016/j.gecco.2020.e00935"
- Description: Private land conservation areas (PLCAs) are increasingly looked to for meeting the deficit left by state-owned protected areas in reaching global conservation targets. However, despite the increasing extent and recognition of PLCAs as a complementary conservation strategy, little research has been done to quantify their effectiveness; a critical consideration if they are to be counted towards international biodiversity conservation targets. The long history of PLCAs in South Africa provides an interesting case study to address this knowledge gap. Here, we quantified the effectiveness of South African PLCAs by comparing losses in natural land cover and biodiversity intactness within PLCAs with different levels of protection to that of unprotected control points. Points within PLCAs were matched with unprotected control points to test the prediction that if PLCAs offer effective protection, losses in natural land cover and biodiversity intactness would be significantly lower within their boundaries in comparison to unprotected controls exposed to similar conditions. Consequences of natural land cover loss on biodiversity intactness were thus assessed, thus advancing standard approaches for quantifying effectiveness.
- Full Text:
- Date Issued: 2020
Effects of a resistance training intervention on the physical fitness of youth in a rural soccer development programme
- Authors: Greyling, Jacob Johannes
- Date: 2020
- Subjects: Physical fitness--Soccer
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/50795 , vital:42701
- Description: Background: Soccer is the most popular sport worldwide with an estimated 270 million people involved in the sport. Soccer is a fast-paced contact team sport that requires physical capabilities such as speed, agility, strength, power, aerobic and anaerobic fitness in addition to technical proficiency. Most goals are preceded by a linear sprint, jump or change of direction which is why the ability to perform fast powerful movements is important. Research has indicated that resistance training performed in combination with high intensity speed and plyometric training, improves athletic performance of soccer players. Aims and Objectives: This study investigated the effects of a resistance training intervention on the physical fitness of youth in a rural soccer development programme in Addo in the Eastern Cape province of South Africa. Methodology: This study employed a quantitative approach in the form of a quasi-experimental design with an experimental and control group. The sample was conveniently selected based on availability of players and on them meeting specific inclusion criteria. Local soccer clubs in the Nomathamsanqa township - an impoverished area in Addo, which forms part of the Addo Soccer Development Programme (ASDP) - were invited to participate in the study. The final sample for this study consisted of 12 participants. A 10-week soccer-based resistance training intervention, addressing the components of physical fitness with specific emphasis on resistance training, was implemented after completion of the baseline testing. The intervention was designed to be suitable for a rural setting. Results: Within group comparisons revealed significant improvements in the experimental group for power (p = 0.028), speed (p = 0.028) and overall performance (grouped physical fitness measures) (p = 0.018) whereas the control group improved significantly in speed (p = 0.043) and regressed significantly in cardiovascular endurance (p = 0.043). Between group comparisons revealed significant differences for overall performance improvement in the experimental group (p = 0.006) and a reduction in cardiovascular endurance in the control group (p = 0.028). The main finding of this study is therefore this: that the individual parameters did not show consistent improvement when viewed in isolation, however that the intervention had a positive effect on overall performance when all the physical fitness measures were computed as a collective result. Conclusion: The results of the study indicate that the intervention had a positive effect on overall performance however more research is required on soccer in rural and disadvantaged settings of South Africa to develop a convincing model for supplementary training other than conventional soccer practice to improve performance and to overcome the unique challenges faced in a rural setting.
- Full Text: false
- Date Issued: 2020
- Authors: Greyling, Jacob Johannes
- Date: 2020
- Subjects: Physical fitness--Soccer
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/50795 , vital:42701
- Description: Background: Soccer is the most popular sport worldwide with an estimated 270 million people involved in the sport. Soccer is a fast-paced contact team sport that requires physical capabilities such as speed, agility, strength, power, aerobic and anaerobic fitness in addition to technical proficiency. Most goals are preceded by a linear sprint, jump or change of direction which is why the ability to perform fast powerful movements is important. Research has indicated that resistance training performed in combination with high intensity speed and plyometric training, improves athletic performance of soccer players. Aims and Objectives: This study investigated the effects of a resistance training intervention on the physical fitness of youth in a rural soccer development programme in Addo in the Eastern Cape province of South Africa. Methodology: This study employed a quantitative approach in the form of a quasi-experimental design with an experimental and control group. The sample was conveniently selected based on availability of players and on them meeting specific inclusion criteria. Local soccer clubs in the Nomathamsanqa township - an impoverished area in Addo, which forms part of the Addo Soccer Development Programme (ASDP) - were invited to participate in the study. The final sample for this study consisted of 12 participants. A 10-week soccer-based resistance training intervention, addressing the components of physical fitness with specific emphasis on resistance training, was implemented after completion of the baseline testing. The intervention was designed to be suitable for a rural setting. Results: Within group comparisons revealed significant improvements in the experimental group for power (p = 0.028), speed (p = 0.028) and overall performance (grouped physical fitness measures) (p = 0.018) whereas the control group improved significantly in speed (p = 0.043) and regressed significantly in cardiovascular endurance (p = 0.043). Between group comparisons revealed significant differences for overall performance improvement in the experimental group (p = 0.006) and a reduction in cardiovascular endurance in the control group (p = 0.028). The main finding of this study is therefore this: that the individual parameters did not show consistent improvement when viewed in isolation, however that the intervention had a positive effect on overall performance when all the physical fitness measures were computed as a collective result. Conclusion: The results of the study indicate that the intervention had a positive effect on overall performance however more research is required on soccer in rural and disadvantaged settings of South Africa to develop a convincing model for supplementary training other than conventional soccer practice to improve performance and to overcome the unique challenges faced in a rural setting.
- Full Text: false
- Date Issued: 2020
Effects of an eight-week lumbar stabilization exercise programme on selected variables of patients with chronic low back pain:
- Abass, Ademola O, Alli, Abiola R, Olagbegi, Oladapo M, Christie, Candice J, Bolarinde, Olufemi S
- Authors: Abass, Ademola O , Alli, Abiola R , Olagbegi, Oladapo M , Christie, Candice J , Bolarinde, Olufemi S
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150307 , vital:38966 , DOI: https://doi.org/10.3329/bjms.v19i3.45864
- Description: Lumbar stabilisation exercise has been shown to reduce pain and disability in patients with low back pain but information on its potential benefits in term of back muscle endurance is scarce. This study was aimed at investigating the effects of augmenting conventional physiotherapy with lumbar stabilization exercises on selected variables of patients with non-specific chronic low back pain (NSCLBP).
- Full Text:
- Date Issued: 2020
- Authors: Abass, Ademola O , Alli, Abiola R , Olagbegi, Oladapo M , Christie, Candice J , Bolarinde, Olufemi S
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150307 , vital:38966 , DOI: https://doi.org/10.3329/bjms.v19i3.45864
- Description: Lumbar stabilisation exercise has been shown to reduce pain and disability in patients with low back pain but information on its potential benefits in term of back muscle endurance is scarce. This study was aimed at investigating the effects of augmenting conventional physiotherapy with lumbar stabilization exercises on selected variables of patients with non-specific chronic low back pain (NSCLBP).
- Full Text:
- Date Issued: 2020
Effects of economic growth on greenhouse emissions
- Mkunyana, Asebenzile Priscilla
- Authors: Mkunyana, Asebenzile Priscilla
- Date: 2020
- Subjects: Greenhouse gases -- Environmental aspects -- Africa , Climate change mitigation
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/50404 , vital:42162
- Description: This study employs the panel cointegration and Pooled Mean Group technique to examine the effects of economic growth on greenhouse emissions using the panel data from the period of 1970 to 2014 for five Southern African Development Community group of countries. The increase in the combustion of burning fossil fuels has become the global threat in environmental quality. The Environmental Kuznets Curve hypothesis postulates that at the primary stages of industrial economies there is more extracting of natural resources and more agricultural activities taking place as a result the waste generation and resource depletion accelerate. However, as the economic development improves more, the curve reaches a threshold where it starts to decline due to the increase in economic growth and the change to information-based industries. Based on the empirical evidence, the variables of this study were found to be stationary at first difference and integrated of I(0) and I(1) using Im, Pesaran & Shin W-stat, Fisher ADF, and Levin, Lin & Chu panel unit root test. The existing long-run relationship between the variables were found in both the Pedroni and Kao cointegration test and were significant at 5% in finding the relationship between the variables. The Pooled Mean Group demonstrated mixed results in the study’s regressions, monotonic relationship was found between carbon dioxide and economic growth. The strong existence relationship between economic growth and energy consumption was found to be significant at the 1% level. These results are in line with the EKC hypothesis, which assumes that as the income level increases the society will start to be environmentally friendly and the technology advancement will decrease the emission of pollutants. In addition, in finding the causal relationship between variables, the researcher used the Granger causality test, with the results from this test revealing a unidirectional and bidirectional relationship between all the chosen variables. These results are important for policy makers.
- Full Text:
- Date Issued: 2020
- Authors: Mkunyana, Asebenzile Priscilla
- Date: 2020
- Subjects: Greenhouse gases -- Environmental aspects -- Africa , Climate change mitigation
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/50404 , vital:42162
- Description: This study employs the panel cointegration and Pooled Mean Group technique to examine the effects of economic growth on greenhouse emissions using the panel data from the period of 1970 to 2014 for five Southern African Development Community group of countries. The increase in the combustion of burning fossil fuels has become the global threat in environmental quality. The Environmental Kuznets Curve hypothesis postulates that at the primary stages of industrial economies there is more extracting of natural resources and more agricultural activities taking place as a result the waste generation and resource depletion accelerate. However, as the economic development improves more, the curve reaches a threshold where it starts to decline due to the increase in economic growth and the change to information-based industries. Based on the empirical evidence, the variables of this study were found to be stationary at first difference and integrated of I(0) and I(1) using Im, Pesaran & Shin W-stat, Fisher ADF, and Levin, Lin & Chu panel unit root test. The existing long-run relationship between the variables were found in both the Pedroni and Kao cointegration test and were significant at 5% in finding the relationship between the variables. The Pooled Mean Group demonstrated mixed results in the study’s regressions, monotonic relationship was found between carbon dioxide and economic growth. The strong existence relationship between economic growth and energy consumption was found to be significant at the 1% level. These results are in line with the EKC hypothesis, which assumes that as the income level increases the society will start to be environmentally friendly and the technology advancement will decrease the emission of pollutants. In addition, in finding the causal relationship between variables, the researcher used the Granger causality test, with the results from this test revealing a unidirectional and bidirectional relationship between all the chosen variables. These results are important for policy makers.
- Full Text:
- Date Issued: 2020
Effects of high-intensity speed training on the speed reserve of university middle-distance and field sport athletes
- Authors: Thomas, Emma Jayne
- Date: 2020
- Subjects: Athletes
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/46346 , vital:39599
- Description: Context: Despite the multiple differences between athletic events and sports, they all share the sporadic bouts of moderate to extreme intensities and all require some contribution from an integrated bioenergetic system to allow for optimal performance. Although D’ is often considered as an ‘anaerobic work capacity’, such a definition is over-simplistic and its precise composition is nebulous, especially given the mixed findings of the experimental evidence. Clearly, further research is needed to provide a more complete understanding of the D’ parameter, as well as the speed reserve(range of speeds exceeding critical speed) especially within high-intensity exercise. Purpose (Aim): The aim of this study is to determine whether a short term high-intensity speed training intervention within the severe intensity domain effects speed reserve in athletic and non-athletic individuals considered moderately trained.Methods: A quantitative research design was used. Participantscompletedbaseline testing (pre-test), after which they were assigned into two groups. Both groups received a HIIT training program, with group 1 (G140%) receiving a program based on intensity prescription (work bouts performed at 140% of CS)and group 2 (G90-s) receiving a program based on time intervals (work bouts performed for 90-s). HIIT sessions were performed twice-weekly for a total of 6-weeks. A post-test assessment was then conducted by both groups to determine whether any changes have accrued in any of the physiological variables in question. Participants of the study met a specific criterion(18 –30 years of age, residing in Nelson Mandela Bay, and met the minimum fitness requirements). Results: No significant between-group differences were evident prior to and following cessation of the HIIT intervention. Findings that can be highlighted holistically include improvements in CS(G140%: M = 0.62 m.s-1; G90-s: M = 0.46 m.s-1)and 𝑉̇𝑂2𝑚𝑎𝑥 (G140%: +3.81 ml.kg-1.min-1; G90-s: +5.19 ml.kg-1.min-1)and a decrease in fatigue index (G140%: M = -6.75%; G90-s: M = -4.38%) and D’(G140%: M = -56.34 m; G90-s: M = -18.36 m).Normative data were generated for athletic and non-athletic participants using the standard nine (Stanine) categorization to facilitate interpretation and recommendations of key parameters for coaches and clinicians. Moreover, a deterministic model was also generated which revealed novel interactions and the strength of the relationship between variables-potentially opening new and innovative areas of future research. Conclusions: The interval durations and speeds utilised in the present study were insufficient to stimulate an increase in D’. To elicit an increase of D’, one would have to decrease the duration of the intervals performed(i.e. < 90-sec), while increasing speed at which the intervals performed at some speed greater than 140% of CS, but below MSS. Further research is needed to understand the physiological underpinning of the D’ parameter both in isolation and in conjunction with CS. It is clear that D’ is influenced by parameters such as MSS, 𝜏d and FI%; therefore, these sub-parameters should be explored further as potentiators for moderating the D’ parameter.
- Full Text:
- Date Issued: 2020
- Authors: Thomas, Emma Jayne
- Date: 2020
- Subjects: Athletes
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/46346 , vital:39599
- Description: Context: Despite the multiple differences between athletic events and sports, they all share the sporadic bouts of moderate to extreme intensities and all require some contribution from an integrated bioenergetic system to allow for optimal performance. Although D’ is often considered as an ‘anaerobic work capacity’, such a definition is over-simplistic and its precise composition is nebulous, especially given the mixed findings of the experimental evidence. Clearly, further research is needed to provide a more complete understanding of the D’ parameter, as well as the speed reserve(range of speeds exceeding critical speed) especially within high-intensity exercise. Purpose (Aim): The aim of this study is to determine whether a short term high-intensity speed training intervention within the severe intensity domain effects speed reserve in athletic and non-athletic individuals considered moderately trained.Methods: A quantitative research design was used. Participantscompletedbaseline testing (pre-test), after which they were assigned into two groups. Both groups received a HIIT training program, with group 1 (G140%) receiving a program based on intensity prescription (work bouts performed at 140% of CS)and group 2 (G90-s) receiving a program based on time intervals (work bouts performed for 90-s). HIIT sessions were performed twice-weekly for a total of 6-weeks. A post-test assessment was then conducted by both groups to determine whether any changes have accrued in any of the physiological variables in question. Participants of the study met a specific criterion(18 –30 years of age, residing in Nelson Mandela Bay, and met the minimum fitness requirements). Results: No significant between-group differences were evident prior to and following cessation of the HIIT intervention. Findings that can be highlighted holistically include improvements in CS(G140%: M = 0.62 m.s-1; G90-s: M = 0.46 m.s-1)and 𝑉̇𝑂2𝑚𝑎𝑥 (G140%: +3.81 ml.kg-1.min-1; G90-s: +5.19 ml.kg-1.min-1)and a decrease in fatigue index (G140%: M = -6.75%; G90-s: M = -4.38%) and D’(G140%: M = -56.34 m; G90-s: M = -18.36 m).Normative data were generated for athletic and non-athletic participants using the standard nine (Stanine) categorization to facilitate interpretation and recommendations of key parameters for coaches and clinicians. Moreover, a deterministic model was also generated which revealed novel interactions and the strength of the relationship between variables-potentially opening new and innovative areas of future research. Conclusions: The interval durations and speeds utilised in the present study were insufficient to stimulate an increase in D’. To elicit an increase of D’, one would have to decrease the duration of the intervals performed(i.e. < 90-sec), while increasing speed at which the intervals performed at some speed greater than 140% of CS, but below MSS. Further research is needed to understand the physiological underpinning of the D’ parameter both in isolation and in conjunction with CS. It is clear that D’ is influenced by parameters such as MSS, 𝜏d and FI%; therefore, these sub-parameters should be explored further as potentiators for moderating the D’ parameter.
- Full Text:
- Date Issued: 2020
Efficacy of the rind physiological disorder oleocellosis control measures in lemon fruit (Citrus limon) under shade netting
- Authors: Njili, Zamazima
- Date: 2020
- Subjects: Citrus fruits--Storage--Diseases and injuries , Citrus--Diseases and pests Citrus fruit industry Citrus products
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/49237 , vital:41613
- Description: Lemon growers aim to produce fruit with no blemishes on the rind. Fruit without blemishes is regarded as high value fruit required for the export market. Leakage of phytotoxic oil from the rind tissues damages them and results in the development of oleocellosis symptoms. Four experiments were conducted to investigate methods of avoiding and controlling the development of oleocellosis during harvest and post-harvest handling. The first experiment indicated that the rind oil release pressure (RORP) test is the method most effective at predicting oleocellosis incidents. The experiment also suggested that fruit not exposed to the sun are the most susceptible to oleocellosis due to low temperatures that cause high turgidity. Oleocellosis results when turgid fruit is mishandled. A cultivar experiment was carried out to ascertain the lemon cultivar most susceptible to oleocellosis. The results show that the Limoneira cultivar is the most susceptible to oleocellosis and 2PH seedless is the least susceptible cultivar when compared to other lemon cultivars such as Lisbon, Eureka and Genoa. When the use of shade netting was tested to determine its effect on oleocellosis severity, it was found that using shade netting did not have an effect. Fruit grown under shade netting had the same colour and average diameter as fruit grown in an open orchard. In the same experiment, mature fruit were shown to be more susceptible to oleocellosis than immature fruit. The final part of the project investigated harvesting and post-harvest practices to determine those that cause oleocellosis the most. It was found that fruit after degreening had greater oleocellosis due to exposure to moisture conditions and rough handling. Another practice that results in oleocellosis occurs before waxing when the fruit was roughly transferred from the bins into the packline. The third oleocellosis inducing practice was moving fruit along the conveyor belt while it is turgid. Improvement of handling procedures to reduce oleocellosis can increase export volume and result in higher value of fruit per carton.
- Full Text:
- Date Issued: 2020
- Authors: Njili, Zamazima
- Date: 2020
- Subjects: Citrus fruits--Storage--Diseases and injuries , Citrus--Diseases and pests Citrus fruit industry Citrus products
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/49237 , vital:41613
- Description: Lemon growers aim to produce fruit with no blemishes on the rind. Fruit without blemishes is regarded as high value fruit required for the export market. Leakage of phytotoxic oil from the rind tissues damages them and results in the development of oleocellosis symptoms. Four experiments were conducted to investigate methods of avoiding and controlling the development of oleocellosis during harvest and post-harvest handling. The first experiment indicated that the rind oil release pressure (RORP) test is the method most effective at predicting oleocellosis incidents. The experiment also suggested that fruit not exposed to the sun are the most susceptible to oleocellosis due to low temperatures that cause high turgidity. Oleocellosis results when turgid fruit is mishandled. A cultivar experiment was carried out to ascertain the lemon cultivar most susceptible to oleocellosis. The results show that the Limoneira cultivar is the most susceptible to oleocellosis and 2PH seedless is the least susceptible cultivar when compared to other lemon cultivars such as Lisbon, Eureka and Genoa. When the use of shade netting was tested to determine its effect on oleocellosis severity, it was found that using shade netting did not have an effect. Fruit grown under shade netting had the same colour and average diameter as fruit grown in an open orchard. In the same experiment, mature fruit were shown to be more susceptible to oleocellosis than immature fruit. The final part of the project investigated harvesting and post-harvest practices to determine those that cause oleocellosis the most. It was found that fruit after degreening had greater oleocellosis due to exposure to moisture conditions and rough handling. Another practice that results in oleocellosis occurs before waxing when the fruit was roughly transferred from the bins into the packline. The third oleocellosis inducing practice was moving fruit along the conveyor belt while it is turgid. Improvement of handling procedures to reduce oleocellosis can increase export volume and result in higher value of fruit per carton.
- Full Text:
- Date Issued: 2020
Efficient market hypothesis : testing weak-form efficiency on the Johannesburg stock exchange
- Authors: Eaton, Bradley Hayes
- Date: 2020
- Subjects: Efficient market theory
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/47895 , vital:40396
- Description: Understanding financial markets is paramount in acknowledging the flow of domestic and foreign funds over time. In this study, net market capitalisation price and simple return characteristics were investigated for the period from January 2009 to December 2017. An empirical, statistical approach was used to explore the possibility that, since the 2008 financial crisis, forward-looking, aggregate market and financial-oriented equity indices have conformed to the Efficient Market Hypothesis. Accordingly, monthly observations were made to ensure long-run traits were identified and scrutinised. Such revelations are important for portfolio diversification, risk, and expected return potentials with respect to South African equity markets. Based on the study, it was found that random walks were evident in both the price and return time-series as a result of significant stochastic price action, supported by evidence suggesting non-normality of price and return distributions. Unit root and stationarity modelling confirmed such traits. However, significant trending behaviours were evident in the auto-correlation figures with regards to prices, despite mean-reverting and stochastic influences. Therefore, it was concluded from the results of the study that the respective time-series were weak-form efficient. The empirical component was supplemented by a comprehensive investigation into the market determinants of financial market inefficiencies, including partial correlations, contagion effects, momentum, financial bubbles, and liquidity issues. Secondary objectives of the study included identifying the roles of security exchanges and the effect of international linkages, as a result of globalisation, on the financial markets. Increased macro-economic and systems integration has led to positive and negative connotations for business cycles. Spill-over effects into global equity markets are evident as can be seen through the co-integration of leading world exchanges, both in the developed and emerging market spheres. Fundamental to this study was the sensitivity of South African equity markets to recessionary pressures, as analysed through the efficiency of aggregated equity indices.
- Full Text:
- Date Issued: 2020
- Authors: Eaton, Bradley Hayes
- Date: 2020
- Subjects: Efficient market theory
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/47895 , vital:40396
- Description: Understanding financial markets is paramount in acknowledging the flow of domestic and foreign funds over time. In this study, net market capitalisation price and simple return characteristics were investigated for the period from January 2009 to December 2017. An empirical, statistical approach was used to explore the possibility that, since the 2008 financial crisis, forward-looking, aggregate market and financial-oriented equity indices have conformed to the Efficient Market Hypothesis. Accordingly, monthly observations were made to ensure long-run traits were identified and scrutinised. Such revelations are important for portfolio diversification, risk, and expected return potentials with respect to South African equity markets. Based on the study, it was found that random walks were evident in both the price and return time-series as a result of significant stochastic price action, supported by evidence suggesting non-normality of price and return distributions. Unit root and stationarity modelling confirmed such traits. However, significant trending behaviours were evident in the auto-correlation figures with regards to prices, despite mean-reverting and stochastic influences. Therefore, it was concluded from the results of the study that the respective time-series were weak-form efficient. The empirical component was supplemented by a comprehensive investigation into the market determinants of financial market inefficiencies, including partial correlations, contagion effects, momentum, financial bubbles, and liquidity issues. Secondary objectives of the study included identifying the roles of security exchanges and the effect of international linkages, as a result of globalisation, on the financial markets. Increased macro-economic and systems integration has led to positive and negative connotations for business cycles. Spill-over effects into global equity markets are evident as can be seen through the co-integration of leading world exchanges, both in the developed and emerging market spheres. Fundamental to this study was the sensitivity of South African equity markets to recessionary pressures, as analysed through the efficiency of aggregated equity indices.
- Full Text:
- Date Issued: 2020
Either way you die: a collection of short stories
- Authors: Sithole, Sipho
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145081 , vital:38406
- Description: Part A: Thesis (Creative Work); Part B: Portfolio.
- Full Text:
- Date Issued: 2020
- Authors: Sithole, Sipho
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145081 , vital:38406
- Description: Part A: Thesis (Creative Work); Part B: Portfolio.
- Full Text:
- Date Issued: 2020
Electricity use behaviour in a high-income neighbourhood in Johannesburg, South Africa:
- Williams, Stephanie P, Thondhlana, Gladman, Kua, Harn W
- Authors: Williams, Stephanie P , Thondhlana, Gladman , Kua, Harn W
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149725 , vital:38878 , https://doi.org/10.3390/su12114571
- Description: Worldwide, households’ consumption of electricity contributes to a substantial proportion of total national energy demand. Thus, the residential sector is a major entity in efforts to define and achieve global sustainability goals. Understanding electricity use behaviour and factors underlying behaviour is critical for designing behaviour change interventions, particularly in contexts characterised by fast-growing economies, burgeoning number of high-income households, and consumption growth. However, relative to developed economies, very little is known on this subject in South Africa. Using structured questionnaires, this study examines electricity use behaviour among high-income households in Johannesburg, South Africa.
- Full Text:
- Date Issued: 2020
- Authors: Williams, Stephanie P , Thondhlana, Gladman , Kua, Harn W
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149725 , vital:38878 , https://doi.org/10.3390/su12114571
- Description: Worldwide, households’ consumption of electricity contributes to a substantial proportion of total national energy demand. Thus, the residential sector is a major entity in efforts to define and achieve global sustainability goals. Understanding electricity use behaviour and factors underlying behaviour is critical for designing behaviour change interventions, particularly in contexts characterised by fast-growing economies, burgeoning number of high-income households, and consumption growth. However, relative to developed economies, very little is known on this subject in South Africa. Using structured questionnaires, this study examines electricity use behaviour among high-income households in Johannesburg, South Africa.
- Full Text:
- Date Issued: 2020
Electrodeposited Benzothiazole Phthalocyanines for Corrosion Inhibition of Aluminium in Acidic Medium
- Nnaji, Nnaemeka, Nwaji, Njemuwa, Nyokong, Tebello
- Authors: Nnaji, Nnaemeka , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186112 , vital:44464 , xlink:href="https://doi.org/10.1155/2020/8892559"
- Description: Tetrakis[(benzo[d]thiazol-2-yl-thio) phthalocyaninato] gallium(III)chloride (1) and tetrakis[(benzo[d]thiazol-2ylphenoxy) phthalocyaninato] gallium(III)chloride (2) were successfully electrodeposited onto aluminium for corrosion retardation in 1.0 M hydrochloric acid solution. The aim of this study was to compare the corrosion resistance of electrodeposited metallated phthalocyanines. Scanning electron microscopy, X-ray diffraction, electrochemical impedance spectroscopy (EIS), and polarization confirmed the aluminium corrosion inhibition potentials of complexes 1 and 2. EIS and polarization techniques showed that complex 2 performed better than complex 1, with values from EIS measurements of 82% for 1 and 86% for 2 in 1.0 M hydrochloric acid solution. The importance of electrodeposition in industries and a dearth of research on the use of electrodeposited metallated phthalocyanines necessitated this study, and results show that coatings formed by electrodeposition of 1 and 2 onto aluminium reduced its susceptibility to corrosion attack.
- Full Text:
- Date Issued: 2020
- Authors: Nnaji, Nnaemeka , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186112 , vital:44464 , xlink:href="https://doi.org/10.1155/2020/8892559"
- Description: Tetrakis[(benzo[d]thiazol-2-yl-thio) phthalocyaninato] gallium(III)chloride (1) and tetrakis[(benzo[d]thiazol-2ylphenoxy) phthalocyaninato] gallium(III)chloride (2) were successfully electrodeposited onto aluminium for corrosion retardation in 1.0 M hydrochloric acid solution. The aim of this study was to compare the corrosion resistance of electrodeposited metallated phthalocyanines. Scanning electron microscopy, X-ray diffraction, electrochemical impedance spectroscopy (EIS), and polarization confirmed the aluminium corrosion inhibition potentials of complexes 1 and 2. EIS and polarization techniques showed that complex 2 performed better than complex 1, with values from EIS measurements of 82% for 1 and 86% for 2 in 1.0 M hydrochloric acid solution. The importance of electrodeposition in industries and a dearth of research on the use of electrodeposited metallated phthalocyanines necessitated this study, and results show that coatings formed by electrodeposition of 1 and 2 onto aluminium reduced its susceptibility to corrosion attack.
- Full Text:
- Date Issued: 2020
Electronic and nonlinear optical properties of 2-(((5-aminonaphthalen-1-yl) imino) methyl) phenol
- Ojo, Nathanael D, Krause, Rui W M, Obi-Egbedi, Nelson O
- Authors: Ojo, Nathanael D , Krause, Rui W M , Obi-Egbedi, Nelson O
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193397 , vital:45328 , xlink:href="https://doi.org/10.1016/j.molliq.2020.114157"
- Description: In this study, solvent dependence of electronic and nonlinear optical properties of a new Schiff base, 2-(((5-aminonaphthalen-1-yl)imino)methyl) phenol (DANOHB), has been investigated. Electronic and optical properties of the Schiff base studied using Uv-visible absorption and fluorescence spectroscopic techniques in solution show that the Schiff base exhibits fluorescence with a quantum yield of 0.21 and a Stokes shift of 39 nm. Quantum chemical calculations were performed on the Schiff base at time-dependent density functional level of theory using Becke-3-Lee-Yang-Parr method with 6-311++G(d,p) basis set. Solvent dependence of the excited state energies (EE), energy gap (ΔE), first-order (β) and second-order (γ) hyperpolarizabilities were studied in gas, cyclohexane and ethanol. The medium perturbed the energy levels which implies that the reactivity, activity and stability of the system are solvent sensitive. The γ is more than thirty times higher than urea (standard NLO material) and this property is further enhanced in less polar medium. Small ΔE and large hyperpolarizabilities obtained for this system suggest its good potential in photonics and nonlinear optical devices.
- Full Text:
- Date Issued: 2020
- Authors: Ojo, Nathanael D , Krause, Rui W M , Obi-Egbedi, Nelson O
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193397 , vital:45328 , xlink:href="https://doi.org/10.1016/j.molliq.2020.114157"
- Description: In this study, solvent dependence of electronic and nonlinear optical properties of a new Schiff base, 2-(((5-aminonaphthalen-1-yl)imino)methyl) phenol (DANOHB), has been investigated. Electronic and optical properties of the Schiff base studied using Uv-visible absorption and fluorescence spectroscopic techniques in solution show that the Schiff base exhibits fluorescence with a quantum yield of 0.21 and a Stokes shift of 39 nm. Quantum chemical calculations were performed on the Schiff base at time-dependent density functional level of theory using Becke-3-Lee-Yang-Parr method with 6-311++G(d,p) basis set. Solvent dependence of the excited state energies (EE), energy gap (ΔE), first-order (β) and second-order (γ) hyperpolarizabilities were studied in gas, cyclohexane and ethanol. The medium perturbed the energy levels which implies that the reactivity, activity and stability of the system are solvent sensitive. The γ is more than thirty times higher than urea (standard NLO material) and this property is further enhanced in less polar medium. Small ΔE and large hyperpolarizabilities obtained for this system suggest its good potential in photonics and nonlinear optical devices.
- Full Text:
- Date Issued: 2020
Electronic and nonlinear optical properties of 3-(((2-substituted-4-nitrophenyl) imino) methyl) phenol
- Ojo, Nathanael D, Krause, Rui W M, Obi-Egbedi, Nelson O
- Authors: Ojo, Nathanael D , Krause, Rui W M , Obi-Egbedi, Nelson O
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193408 , vital:45329 , xlink:href="https://doi.org/10.1016/j.comptc.2020.113050"
- Description: This work entails the study of electronic and nonlinear optical (NLO) properties of two synthesized Schiff bases namely 3-(((2-methyl-4-nitrophenyl)imino)methyl)phenol (MMP) and 3-(((2,4-dinitrophenyl)imino)methyl)phenol (DMP). Electronic absorption properties studied using UV–Visible spectrophotometry in ethanol reveal low-energy absorption indicating a low band gap. Time-dependent density functional calculations on their excited state properties with ωB97X-D/6-311++G(d,p) method show comparable transition energies and intensities with the experimental results. Energy gaps (ΔE) and NLO properties were evaluated from the frontier orbitals and hyperpolarizabilities (βtot and γ) in gas, cyclohexane and ethanol. Low ΔE obtained shows the potentials of the systems as organic semiconductor with remarkable band gap stabilization in ethanol. Higher βtot and γ than urea imply that the Schiff bases possess potentials for NLO applications. The solvatochromic shift in transition energies and perturbation of electronic properties reveal the solvent dependence of the electronic and optical properties of MMP and DMP due to solute-solvent interactions.
- Full Text:
- Date Issued: 2020
- Authors: Ojo, Nathanael D , Krause, Rui W M , Obi-Egbedi, Nelson O
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193408 , vital:45329 , xlink:href="https://doi.org/10.1016/j.comptc.2020.113050"
- Description: This work entails the study of electronic and nonlinear optical (NLO) properties of two synthesized Schiff bases namely 3-(((2-methyl-4-nitrophenyl)imino)methyl)phenol (MMP) and 3-(((2,4-dinitrophenyl)imino)methyl)phenol (DMP). Electronic absorption properties studied using UV–Visible spectrophotometry in ethanol reveal low-energy absorption indicating a low band gap. Time-dependent density functional calculations on their excited state properties with ωB97X-D/6-311++G(d,p) method show comparable transition energies and intensities with the experimental results. Energy gaps (ΔE) and NLO properties were evaluated from the frontier orbitals and hyperpolarizabilities (βtot and γ) in gas, cyclohexane and ethanol. Low ΔE obtained shows the potentials of the systems as organic semiconductor with remarkable band gap stabilization in ethanol. Higher βtot and γ than urea imply that the Schiff bases possess potentials for NLO applications. The solvatochromic shift in transition energies and perturbation of electronic properties reveal the solvent dependence of the electronic and optical properties of MMP and DMP due to solute-solvent interactions.
- Full Text:
- Date Issued: 2020
Elucidation of the effect of cannabinoids on ER stress to determine their molecular mechanism of action in breast cancer cells
- Authors: De la Harpe, Amy
- Date: 2020
- Subjects: Endoplasmic reticulum -- Pathophysiology , Breast -- Cancer -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48213 , vital:40525
- Description: Endoplasmic reticulum (ER) stress is defined as an imbalance between the ER’s protein-folding load and folding capacity. ER stress is induced by various physiological conditions and subsequently triggers the activation of the unfolded protein response (UPR) to re-establish homeostasis and promote cell survival. However, under severe or chronic stress, apoptosis is induced. Normal cells generally do not experience ER stress; however, stressful conditions in the tumour micro-environment facilitates chronic ER stress and UPR activation, which plays a pivotal role in tumour survival. Exacerbation of pre-existing ER stress can trigger cancer cell death, with a minimal effect on normal cells. Currently, no high-throughput method exists to detect and quantify ER stress in cell lines. This study showed that Thioflavin T, a fluorescent dye that binds to misfolded protein aggregates, can be used for the high-throughput detection of ER stress, and provides several advantages over currently used methods. Current literature suggests that cannabinoid treatment may induce cancer cell death via ER stress, however little is known about the mechanism of induction. This study proposed a mechanism that occurs via the influx of Ca2+ via the vanilloid receptor 1 (TRPV1), and subsequent ROS production, which affects protein folding. ER stress was induced using various cannabinoids and measured using Thioflavin T and western blot analysis. The effect of cannabinoid treatment on ROS production and the intracellular Ca2+ concentration was measured. Cannabidiol (CBD) was the most potent ER stress inducer, significantly increasing Ca2+ and ROS accumulation; however, the level of accumulated Ca2+ across cell lines varied, which may be due to the differences in the TRPV1 expression and localization. Concomitant treatment of CBD with an antioxidant significantly increased cell viability and decreased ER stress induction in the MCF7 cell line. Concomitant treatment with a TRPV1 antagonist increased viability in this cell line. In conclusion, the results suggested that CBD may induce ER stress via Ca2+ influx through the TRPV1 receptor, thereby elevating intracellular ROS levels and disrupting protein folding.
- Full Text:
- Date Issued: 2020
- Authors: De la Harpe, Amy
- Date: 2020
- Subjects: Endoplasmic reticulum -- Pathophysiology , Breast -- Cancer -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48213 , vital:40525
- Description: Endoplasmic reticulum (ER) stress is defined as an imbalance between the ER’s protein-folding load and folding capacity. ER stress is induced by various physiological conditions and subsequently triggers the activation of the unfolded protein response (UPR) to re-establish homeostasis and promote cell survival. However, under severe or chronic stress, apoptosis is induced. Normal cells generally do not experience ER stress; however, stressful conditions in the tumour micro-environment facilitates chronic ER stress and UPR activation, which plays a pivotal role in tumour survival. Exacerbation of pre-existing ER stress can trigger cancer cell death, with a minimal effect on normal cells. Currently, no high-throughput method exists to detect and quantify ER stress in cell lines. This study showed that Thioflavin T, a fluorescent dye that binds to misfolded protein aggregates, can be used for the high-throughput detection of ER stress, and provides several advantages over currently used methods. Current literature suggests that cannabinoid treatment may induce cancer cell death via ER stress, however little is known about the mechanism of induction. This study proposed a mechanism that occurs via the influx of Ca2+ via the vanilloid receptor 1 (TRPV1), and subsequent ROS production, which affects protein folding. ER stress was induced using various cannabinoids and measured using Thioflavin T and western blot analysis. The effect of cannabinoid treatment on ROS production and the intracellular Ca2+ concentration was measured. Cannabidiol (CBD) was the most potent ER stress inducer, significantly increasing Ca2+ and ROS accumulation; however, the level of accumulated Ca2+ across cell lines varied, which may be due to the differences in the TRPV1 expression and localization. Concomitant treatment of CBD with an antioxidant significantly increased cell viability and decreased ER stress induction in the MCF7 cell line. Concomitant treatment with a TRPV1 antagonist increased viability in this cell line. In conclusion, the results suggested that CBD may induce ER stress via Ca2+ influx through the TRPV1 receptor, thereby elevating intracellular ROS levels and disrupting protein folding.
- Full Text:
- Date Issued: 2020
Employee retention as a strategy for the sustainability of rehabilitation services within the Nelson Mandela Bay Health District
- Authors: Campbell, Teneille Dawn
- Date: 2020
- Subjects: Employee retention--South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/47530 , vital:40124
- Description: Health care facilities in the South African public sector have, over time, become notorious for poor service delivery, peppered with issues of poor governance, weak administration capabilities, and ailing working conditions. Often, the consequence hereof is a loss of good talent to both the private sector and health sectors abroad, all the while placing more strain on institutional service delivery capabilities. To achieve the United Nation’s Sustainable Development Goal (SDG) of Universal Health Coverage (UHC) by 2030, the strengthening of health systems is critical. The purpose of this study is therefore to offer supportable solutions to improve and maintain a sustainable rehabilitation service in the Nelson Mandela Metro through successful retention of staff. The aim of this study then is to investigate the influence that Human Resources (HR) processes, working conditions and leadership have had on retention of staff. A review of the available literature was conducted on possible factors that contribute to the problem and the solutions thereof. The study population included all staff that worked in rehabilitation service departments in the public health institutions in the Nelson Mandela Metro, namely; physiotherapy, occupational therapy, speech therapy and audiology. The sample constituted n=51 respondents. Data was collected via a questionnaire as the selected measurement tool. The data was analysed using the statistical data analysis software system, TIBCO Statistica (version 13), and selected methods for quantitative data. The results of the study showed that only HR processes were significantly and positively (r = 0.67, p < 0.05) related to retention. It means that satisfying the HR needs of this population is most likely to retain their employ and improve and maintain rehabilitation service delivery in the selected metro. Descriptive statistics of all the variables were also calculated and reported on. Lastly, the managerial implications of the study findings were reported on.
- Full Text:
- Date Issued: 2020
- Authors: Campbell, Teneille Dawn
- Date: 2020
- Subjects: Employee retention--South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/47530 , vital:40124
- Description: Health care facilities in the South African public sector have, over time, become notorious for poor service delivery, peppered with issues of poor governance, weak administration capabilities, and ailing working conditions. Often, the consequence hereof is a loss of good talent to both the private sector and health sectors abroad, all the while placing more strain on institutional service delivery capabilities. To achieve the United Nation’s Sustainable Development Goal (SDG) of Universal Health Coverage (UHC) by 2030, the strengthening of health systems is critical. The purpose of this study is therefore to offer supportable solutions to improve and maintain a sustainable rehabilitation service in the Nelson Mandela Metro through successful retention of staff. The aim of this study then is to investigate the influence that Human Resources (HR) processes, working conditions and leadership have had on retention of staff. A review of the available literature was conducted on possible factors that contribute to the problem and the solutions thereof. The study population included all staff that worked in rehabilitation service departments in the public health institutions in the Nelson Mandela Metro, namely; physiotherapy, occupational therapy, speech therapy and audiology. The sample constituted n=51 respondents. Data was collected via a questionnaire as the selected measurement tool. The data was analysed using the statistical data analysis software system, TIBCO Statistica (version 13), and selected methods for quantitative data. The results of the study showed that only HR processes were significantly and positively (r = 0.67, p < 0.05) related to retention. It means that satisfying the HR needs of this population is most likely to retain their employ and improve and maintain rehabilitation service delivery in the selected metro. Descriptive statistics of all the variables were also calculated and reported on. Lastly, the managerial implications of the study findings were reported on.
- Full Text:
- Date Issued: 2020
Enabling violence: the ethics of writing and reading rape in South Africa
- Authors: Lloyd, Dylan Reumen
- Date: 2020
- Subjects: Rape -- South Africa , Rape -- Fiction , Rape in literature , Rape in literature -- South Africa , Psychic trauma in literature , Post-traumatic stress disorder in literature , Dystopias in literature , Coetzee, J. M., 1940- Disgrace , South African fiction (English) -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/166173 , vital:41335
- Description: This thesis is concerned with describing the stakes of reading, writing and criticising fictional depictions of rape in a country plagued by high levels of sexual violence. I consider the capacity of rape representations to cause harm to women and rape survivors, and worsen the various injuries suffered by survivors as a direct or indirect consequence of rape. The possibility of such harm prompts me to examine the role and responsibilities of readers and critics in facilitating or preventing such harm. I further discuss the potential strategies of harm prevention that readers of novelistic portrayals of rape might adopt as well as the positive outcomes that such reading strategies make possible, and which might balance out the risks that accompany them. My description of the potential harm of rape representations combines postmodern critical feminist analysis with Miranda Fricker’s work on epistemic justice and Judith Herman’s work on trauma in order to illustrate the way that these representations shape our conception of rape in a manner that affects everything from how it is enacted to our treatment of survivors to the possibility of their recovery from posttraumatic stress disorder. In order to situate my analysis in the context of South African literature and to explore the notion of responsibility in relation to the writing of scenes of rape, I utilise a close reading of J.M. Coetzee’s Disgrace. Furthermore, I discuss the utility and limits of the critical feminist strategy of using a normative critical approach to rape representations in order to prevent harm. Ultimately, I argue that the use of such a strategy, along with the development of a purpose-honed adaptive critical style, is essential to the fulfilment of our responsibilities as readers and to the prevention of further suffering.
- Full Text:
- Date Issued: 2020
- Authors: Lloyd, Dylan Reumen
- Date: 2020
- Subjects: Rape -- South Africa , Rape -- Fiction , Rape in literature , Rape in literature -- South Africa , Psychic trauma in literature , Post-traumatic stress disorder in literature , Dystopias in literature , Coetzee, J. M., 1940- Disgrace , South African fiction (English) -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/166173 , vital:41335
- Description: This thesis is concerned with describing the stakes of reading, writing and criticising fictional depictions of rape in a country plagued by high levels of sexual violence. I consider the capacity of rape representations to cause harm to women and rape survivors, and worsen the various injuries suffered by survivors as a direct or indirect consequence of rape. The possibility of such harm prompts me to examine the role and responsibilities of readers and critics in facilitating or preventing such harm. I further discuss the potential strategies of harm prevention that readers of novelistic portrayals of rape might adopt as well as the positive outcomes that such reading strategies make possible, and which might balance out the risks that accompany them. My description of the potential harm of rape representations combines postmodern critical feminist analysis with Miranda Fricker’s work on epistemic justice and Judith Herman’s work on trauma in order to illustrate the way that these representations shape our conception of rape in a manner that affects everything from how it is enacted to our treatment of survivors to the possibility of their recovery from posttraumatic stress disorder. In order to situate my analysis in the context of South African literature and to explore the notion of responsibility in relation to the writing of scenes of rape, I utilise a close reading of J.M. Coetzee’s Disgrace. Furthermore, I discuss the utility and limits of the critical feminist strategy of using a normative critical approach to rape representations in order to prevent harm. Ultimately, I argue that the use of such a strategy, along with the development of a purpose-honed adaptive critical style, is essential to the fulfilment of our responsibilities as readers and to the prevention of further suffering.
- Full Text:
- Date Issued: 2020