Local web news as tools for framing food security: the content analysis of four selected Eastern Cape web newspapers
- Metula , Nolukhanyo Theorida
- Authors: Metula , Nolukhanyo Theorida
- Date: 2019
- Subjects: Food security World Wide Web
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/17484 , vital:41080
- Description: This study evaluates how the Eastern Cape local web newspapers frame food security in the Eastern Cape Province. A qualitative content analysis by means of textual analysis was used to evaluate the selected local web newspaper’s content on food security related stories within the period of July-December 2017. The sample was drawn from four Eastern Cape local web newspapers- Daily Dispatch Live, Herald Live, Go and Express and The Talk of the Town. The analysis sought to determine how the selected local web newspapers frame food security concerning food availability, accessibility and affordability in the Eastern Cape Province. Additionally, the study aimed to ascertain the issues about food security that are raised by the Eastern Cape local web newspapers and, to establish the extent to which these Eastern Cape local web newspapers’ framing is helpful in ensuring participation, empowerment and community mobilization for food securing purposes. The results of this study indicate that the local web newspapers frame Eastern Cape Province as untapped food basket. The framing suggests that the Province can leverage its agricultural resources for job creation which will ensure economic growth and food security. The local web newspapers framing suggests that there are numerous channels such as natural food production, livestock production, smallholder farming that can enhance availability and access to affordable food to people in the Eastern Cape Province. The findings revealed that local web newspapers frame increased agricultural production as an important issue that demand serious and urgent attention of the Provincial government as it has the potential of not only ensuring food security but also impacting positively on the income of local farmers. The local web newspapers frame farm attacks, land redistribution and reinstatement as important factors that hinder food production and, ultimately, food security in the Eastern Cape v Province. Furthermore, this study discovered that the frame of references used by the local web newspapers, especially the emphasis on local farming, land redistribution and private sector help to empower and mobilize individuals and communities to participate in food security initiatives. This study concludes that Eastern Cape Local Web Newspapers can be veritable tools to enhance food security channels in the Eastern Cape Province
- Full Text:
- Date Issued: 2019
- Authors: Metula , Nolukhanyo Theorida
- Date: 2019
- Subjects: Food security World Wide Web
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/17484 , vital:41080
- Description: This study evaluates how the Eastern Cape local web newspapers frame food security in the Eastern Cape Province. A qualitative content analysis by means of textual analysis was used to evaluate the selected local web newspaper’s content on food security related stories within the period of July-December 2017. The sample was drawn from four Eastern Cape local web newspapers- Daily Dispatch Live, Herald Live, Go and Express and The Talk of the Town. The analysis sought to determine how the selected local web newspapers frame food security concerning food availability, accessibility and affordability in the Eastern Cape Province. Additionally, the study aimed to ascertain the issues about food security that are raised by the Eastern Cape local web newspapers and, to establish the extent to which these Eastern Cape local web newspapers’ framing is helpful in ensuring participation, empowerment and community mobilization for food securing purposes. The results of this study indicate that the local web newspapers frame Eastern Cape Province as untapped food basket. The framing suggests that the Province can leverage its agricultural resources for job creation which will ensure economic growth and food security. The local web newspapers framing suggests that there are numerous channels such as natural food production, livestock production, smallholder farming that can enhance availability and access to affordable food to people in the Eastern Cape Province. The findings revealed that local web newspapers frame increased agricultural production as an important issue that demand serious and urgent attention of the Provincial government as it has the potential of not only ensuring food security but also impacting positively on the income of local farmers. The local web newspapers frame farm attacks, land redistribution and reinstatement as important factors that hinder food production and, ultimately, food security in the Eastern Cape v Province. Furthermore, this study discovered that the frame of references used by the local web newspapers, especially the emphasis on local farming, land redistribution and private sector help to empower and mobilize individuals and communities to participate in food security initiatives. This study concludes that Eastern Cape Local Web Newspapers can be veritable tools to enhance food security channels in the Eastern Cape Province
- Full Text:
- Date Issued: 2019
Medicinal Plants Used to Treat and Manage Respiratory Infections in the Limpopo Province, South Africa: Phytotherapeutic Study of Bapedi Traditional Healers’ Practices
- Authors: Semenya, Sebua Silas
- Date: 2019
- Subjects: Medicinal plants Respiratory infections -- Alternative treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15716 , vital:40512
- Description: There is paucity of data on South African traditional healers’ (THs) phytotherapeutic practices regarding respiratory infections (RIs). Several people in South Africa are contracting RIs due to prevalence of risk factors. This situation is exacerbated by limited modern health care facilities and associated personnel in some provinces in the country. The primary objectives of this study were twofold. First purpose was to execute a comprehensive social and ethnobotanical surveys aimed at (a) establishing the types of RIs treated by THs and diagnosis techniques used, (b) plants used as therapies for RIs and associated indigenous knowledge practices, (c) source/s of plants used as medicines, (d) harvesting practices, current local availability status, conservation status and threats of indigenous plants as well as the level of conservation knowledge possessed by THs. The second objective was to assess the therapeutic value of the four most frequently used plant species by THs by (a) analysing the phytochemical profile of the plant extracts, (b) their antioxidant activities, and (c) their antibacterial activities. Information linked to the social and ethnobotanical surveys was gathered via a semi-structured questionnaires, supplemented by field observations during face-to-face interview with 240 conveniently selected THs practicing in the municipalities of Capricorn, Sekhukhune and Waterberg districts of the Limpopo Province, South Africa. Data were generally analysed using Microsoft Excel and Statistical Package for the Social Sciences (SPSS). In addition to these softwares, ethnobotanical data were analysed via quantitative ethnobotanical indexes namely use mention (UM), fidelity level (FL), use value (UV) and preference ranking (PR). For laboratory experiments, qualitative phytochemical constitutes of the crude extracts were determined using the standard screening methods. The antioxidant activities of acetone, dichlomethane, hexane, methanol and water crude extracts were evaluated using qualitative and quantitative 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assays. Antibacterial activities of these extracts was assessed using microdilution and bioautography assays. Six types of RIs; tuberculosis (84.1%), sore throat (65%), asthma (58.3%), sinusitis (55%), pneumonia (53.3%) and rhinitis (43.7%) were treated by THs practicing as herbalists (58.7%), herbalists and diviners (40.5%), and diviners (0.4%). The identification of these RIs was based on the patients’ presentation of certain clinical symptoms, with THs practicing both herbalism and divination additionally using bone casting. There was a broad overlap between the clinical signs used to diagnose most of the RIs, and the specificity of symptoms followed when ascertaining an individual infection was low. A total of 224 plant species (83% indigenous and 16.9% exotics) belonging to 177 genera and 85 botanical families, mainly the Fabaceae (25 spp.) and Asteraceae (16 spp.) were used by THs as herbal medicines for the aforesaid RIs and perceived related symptoms (RSs). Most of the documented plant species were used for tuberculosis (82.1%) and asthma (46.4%). Roots (64%) and leaves (13%) formed an important mainstay for medicinal recipes preparations. Different routes of administering these recipes were noted, with oral (75.6%) and nasal (18.8%) being the most preferred. The most widely used species by THs to treat and manage all the six RIs with high UM, FL, UV and PR values included Clerodendrum ternatum, Cryptocarya transvaalensis, Enicostema axillare, Lasiosiphon caffer and Stylochaeton natalensis. Overall larger numbers of species used by Bapedi THs including the mentioned ones are recorded for the first time in scientific literature as remedies for RIs and RSs, thus reflecting a need for more similar studies amongst other ethnic groups of South Africa and elsewhere. The phytochemical screening of four most used plants C. ternatum, C. transvaalensis, E. axillare and L. caffer crude extracts revealed the presence of alkaloids, anthraquinones, cardiac glycosides, flavonoids, phlobatannin, saponins, steroids, tannins and terpenes. All plants including those that did not display any antioxidant activities using qualitative DPPH assay displayed a certain level of scavenging activity when quantified, with the mentioned extracts from E. axillare (water and hexane), L. caffer (water and acetone) and C. ternatum (acetone) showing excellent activity almost comparable to a standard antioxidant drug (ascorbic acid). Plant extracts from all used solvents were active against Mycobacterium smegmatis, Klebsiella pneumoniae, Staphylococcus aureus and Pseudomonas aeruginosa with miniumum bactericidal concentration values ranging between 0.019 and 2.5 mg/ml depending on the plant species. Some of plant extracts exhibited minimum inhibitory concentration values ranging between 0.63 to 2.5 mg/ml. This study showed that most of the diagnosis methods used by Bapedi THs and their herbal medicines have the potential to contribute towards the management and treatment of RIs and RSs. iii | Page Future endeavour should be focused on the following: (a) possibility of collaboration between questioned THs and local western health care practitioners in the treatment of these diseases, and (b) isolation, purification and characterization of the biologically active compounds from extract of the above-stated plants, amongst other inquiries.
- Full Text:
- Date Issued: 2019
- Authors: Semenya, Sebua Silas
- Date: 2019
- Subjects: Medicinal plants Respiratory infections -- Alternative treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15716 , vital:40512
- Description: There is paucity of data on South African traditional healers’ (THs) phytotherapeutic practices regarding respiratory infections (RIs). Several people in South Africa are contracting RIs due to prevalence of risk factors. This situation is exacerbated by limited modern health care facilities and associated personnel in some provinces in the country. The primary objectives of this study were twofold. First purpose was to execute a comprehensive social and ethnobotanical surveys aimed at (a) establishing the types of RIs treated by THs and diagnosis techniques used, (b) plants used as therapies for RIs and associated indigenous knowledge practices, (c) source/s of plants used as medicines, (d) harvesting practices, current local availability status, conservation status and threats of indigenous plants as well as the level of conservation knowledge possessed by THs. The second objective was to assess the therapeutic value of the four most frequently used plant species by THs by (a) analysing the phytochemical profile of the plant extracts, (b) their antioxidant activities, and (c) their antibacterial activities. Information linked to the social and ethnobotanical surveys was gathered via a semi-structured questionnaires, supplemented by field observations during face-to-face interview with 240 conveniently selected THs practicing in the municipalities of Capricorn, Sekhukhune and Waterberg districts of the Limpopo Province, South Africa. Data were generally analysed using Microsoft Excel and Statistical Package for the Social Sciences (SPSS). In addition to these softwares, ethnobotanical data were analysed via quantitative ethnobotanical indexes namely use mention (UM), fidelity level (FL), use value (UV) and preference ranking (PR). For laboratory experiments, qualitative phytochemical constitutes of the crude extracts were determined using the standard screening methods. The antioxidant activities of acetone, dichlomethane, hexane, methanol and water crude extracts were evaluated using qualitative and quantitative 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assays. Antibacterial activities of these extracts was assessed using microdilution and bioautography assays. Six types of RIs; tuberculosis (84.1%), sore throat (65%), asthma (58.3%), sinusitis (55%), pneumonia (53.3%) and rhinitis (43.7%) were treated by THs practicing as herbalists (58.7%), herbalists and diviners (40.5%), and diviners (0.4%). The identification of these RIs was based on the patients’ presentation of certain clinical symptoms, with THs practicing both herbalism and divination additionally using bone casting. There was a broad overlap between the clinical signs used to diagnose most of the RIs, and the specificity of symptoms followed when ascertaining an individual infection was low. A total of 224 plant species (83% indigenous and 16.9% exotics) belonging to 177 genera and 85 botanical families, mainly the Fabaceae (25 spp.) and Asteraceae (16 spp.) were used by THs as herbal medicines for the aforesaid RIs and perceived related symptoms (RSs). Most of the documented plant species were used for tuberculosis (82.1%) and asthma (46.4%). Roots (64%) and leaves (13%) formed an important mainstay for medicinal recipes preparations. Different routes of administering these recipes were noted, with oral (75.6%) and nasal (18.8%) being the most preferred. The most widely used species by THs to treat and manage all the six RIs with high UM, FL, UV and PR values included Clerodendrum ternatum, Cryptocarya transvaalensis, Enicostema axillare, Lasiosiphon caffer and Stylochaeton natalensis. Overall larger numbers of species used by Bapedi THs including the mentioned ones are recorded for the first time in scientific literature as remedies for RIs and RSs, thus reflecting a need for more similar studies amongst other ethnic groups of South Africa and elsewhere. The phytochemical screening of four most used plants C. ternatum, C. transvaalensis, E. axillare and L. caffer crude extracts revealed the presence of alkaloids, anthraquinones, cardiac glycosides, flavonoids, phlobatannin, saponins, steroids, tannins and terpenes. All plants including those that did not display any antioxidant activities using qualitative DPPH assay displayed a certain level of scavenging activity when quantified, with the mentioned extracts from E. axillare (water and hexane), L. caffer (water and acetone) and C. ternatum (acetone) showing excellent activity almost comparable to a standard antioxidant drug (ascorbic acid). Plant extracts from all used solvents were active against Mycobacterium smegmatis, Klebsiella pneumoniae, Staphylococcus aureus and Pseudomonas aeruginosa with miniumum bactericidal concentration values ranging between 0.019 and 2.5 mg/ml depending on the plant species. Some of plant extracts exhibited minimum inhibitory concentration values ranging between 0.63 to 2.5 mg/ml. This study showed that most of the diagnosis methods used by Bapedi THs and their herbal medicines have the potential to contribute towards the management and treatment of RIs and RSs. iii | Page Future endeavour should be focused on the following: (a) possibility of collaboration between questioned THs and local western health care practitioners in the treatment of these diseases, and (b) isolation, purification and characterization of the biologically active compounds from extract of the above-stated plants, amongst other inquiries.
- Full Text:
- Date Issued: 2019
Model for the alleviation of poverty in South Africa
- Authors: Visagie, Jana
- Date: 2019
- Subjects: Poverty -- South Africa , Poverty -- Prevention
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/45701 , vital:38956
- Description: The existence of extreme poverty in an affluent world is morally unacceptable and action needs to be taken. The reduction of economic and social inequality within countries and between countries, as well as the honouring of human rights, is of utmost importance, but the eradication of poverty must take priority One of the main problems with poverty is that poverty impedes human flourishing). People are hungry and constantly live in pain and anguish while education is hampered. People do not develop fully on cognitive and physical levels as poverty allows the exploitation of the poor and their bodies. Feelings of shame and worthlessness are established for reasons people cannot control. To contribute to the ongoing attempts to reduce poverty, it is necessary to have an understanding as to why people remain poor in an affluent world and what can be done to address the causes of poverty. Unless a global culture of ethics and value alignment is pursued for the reduction of poverty, there will be devastating effects for the future Underwriting lasting escapes from chronic poverty demands more investment in education, employment and human development potentials and in the related infrastructure that permits people to enhance their living standards while developing their resilience to handle setbacks and the effects of climate change.ffects include, for example, disaster-risk management, global healthcare and social cohesion. These investment efforts 9 have the ability to generate a virtuous cycle of poverty reduction, national economic growth and enlarged individual opportunity This could diminish the inequalities that decelerate human development. The lack of practical and outcome-based poverty reduction models affords this research with a unique opportunity to fulfil the need and to contribute to the body of knowledge regarding the reduction of poverty towards 2030.
- Full Text:
- Date Issued: 2019
- Authors: Visagie, Jana
- Date: 2019
- Subjects: Poverty -- South Africa , Poverty -- Prevention
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/45701 , vital:38956
- Description: The existence of extreme poverty in an affluent world is morally unacceptable and action needs to be taken. The reduction of economic and social inequality within countries and between countries, as well as the honouring of human rights, is of utmost importance, but the eradication of poverty must take priority One of the main problems with poverty is that poverty impedes human flourishing). People are hungry and constantly live in pain and anguish while education is hampered. People do not develop fully on cognitive and physical levels as poverty allows the exploitation of the poor and their bodies. Feelings of shame and worthlessness are established for reasons people cannot control. To contribute to the ongoing attempts to reduce poverty, it is necessary to have an understanding as to why people remain poor in an affluent world and what can be done to address the causes of poverty. Unless a global culture of ethics and value alignment is pursued for the reduction of poverty, there will be devastating effects for the future Underwriting lasting escapes from chronic poverty demands more investment in education, employment and human development potentials and in the related infrastructure that permits people to enhance their living standards while developing their resilience to handle setbacks and the effects of climate change.ffects include, for example, disaster-risk management, global healthcare and social cohesion. These investment efforts 9 have the ability to generate a virtuous cycle of poverty reduction, national economic growth and enlarged individual opportunity This could diminish the inequalities that decelerate human development. The lack of practical and outcome-based poverty reduction models affords this research with a unique opportunity to fulfil the need and to contribute to the body of knowledge regarding the reduction of poverty towards 2030.
- Full Text:
- Date Issued: 2019
Modelling storm-time TEC changes using linear and non-linear techniques
- Authors: Uwamahoro, Jean Claude
- Date: 2019
- Subjects: Magnetic storms , Astronomy -- Computer programs , Imaging systems in astronomy , Ionospheric storms , Electrons -- Measurement , Magnetosphere -- Observations
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92908 , vital:30762
- Description: Statistical models based on empirical orthogonal functions (EOF) analysis and non-linear regression analysis (NLRA) were developed for the purpose of estimating the ionospheric total electron content (TEC) during geomagnetic storms. The well-known least squares method (LSM) and Metropolis-Hastings algorithm (MHA) were used as optimization techniques to determine the unknown coefficients of the developed analytical expressions. Artificial Neural Networks (ANNs), the International Reference Ionosphere (IRI) model, and the Multi-Instrument Data Analysis System (MIDAS) tomographic inversion algorithm were also applied to storm-time TEC modelling/reconstruction for various latitudes of the African sector and surrounding areas. This work presents some of the first statistical modeling of the mid-latitude and low-latitude ionosphere during geomagnetic storms that includes solar, geomagnetic and neutral wind drivers.Development and validation of the empirical models were based on storm-time TEC data derived from the global positioning system (GPS) measurements over ground receivers within Africa and surrounding areas. The storm criterion applied was Dst 6 −50 nT and/or Kp > 4. The performance evaluation of MIDAS compared with ANNs to reconstruct storm-time TEC over the African low- and mid-latitude regions showed that MIDAS and ANNs provide comparable results. Their respective mean absolute error (MAE) values were 4.81 and 4.18 TECU. The ANN model was, however, found to perform 24.37 % better than MIDAS at estimating storm-time TEC for low latitudes, while MIDAS is 13.44 % more accurate than ANN for the mid-latitudes. When their performances are compared with the IRI model, both MIDAS and ANN model were found to provide more accurate storm-time TEC reconstructions for the African low- and mid-latitude regions. A comparative study of the performances of EOF, NLRA, ANN, and IRI models to estimate TEC during geomagnetic storm conditions over various latitudes showed that the ANN model is about 10 %, 26 %, and 58 % more accurate than EOF, NLRA, and IRI models, respectively, while EOF was found to perform 15 %, and 44 % better than NLRA and IRI, respectively. It was further found that the NLRA model is 25 % more accurate than the IRI model. We have also investigated for the first time, the role of meridional neutral winds (from the Horizontal Wind Model) to storm-time TEC modelling in the low latitude, northern and southern hemisphere mid-latitude regions of the African sector, based on ANN models. Statistics have shown that the inclusion of the meridional wind velocity in TEC modelling during geomagnetic storms leads to percentage improvements of about 5 % for the low latitude, 10 % and 5 % for the northern and southern hemisphere mid-latitude regions, respectively. High-latitude storm-induced winds and the inter-hemispheric blows of the meridional winds from summer to winter hemisphere have been suggested to be associated with these improvements.
- Full Text:
- Date Issued: 2019
- Authors: Uwamahoro, Jean Claude
- Date: 2019
- Subjects: Magnetic storms , Astronomy -- Computer programs , Imaging systems in astronomy , Ionospheric storms , Electrons -- Measurement , Magnetosphere -- Observations
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92908 , vital:30762
- Description: Statistical models based on empirical orthogonal functions (EOF) analysis and non-linear regression analysis (NLRA) were developed for the purpose of estimating the ionospheric total electron content (TEC) during geomagnetic storms. The well-known least squares method (LSM) and Metropolis-Hastings algorithm (MHA) were used as optimization techniques to determine the unknown coefficients of the developed analytical expressions. Artificial Neural Networks (ANNs), the International Reference Ionosphere (IRI) model, and the Multi-Instrument Data Analysis System (MIDAS) tomographic inversion algorithm were also applied to storm-time TEC modelling/reconstruction for various latitudes of the African sector and surrounding areas. This work presents some of the first statistical modeling of the mid-latitude and low-latitude ionosphere during geomagnetic storms that includes solar, geomagnetic and neutral wind drivers.Development and validation of the empirical models were based on storm-time TEC data derived from the global positioning system (GPS) measurements over ground receivers within Africa and surrounding areas. The storm criterion applied was Dst 6 −50 nT and/or Kp > 4. The performance evaluation of MIDAS compared with ANNs to reconstruct storm-time TEC over the African low- and mid-latitude regions showed that MIDAS and ANNs provide comparable results. Their respective mean absolute error (MAE) values were 4.81 and 4.18 TECU. The ANN model was, however, found to perform 24.37 % better than MIDAS at estimating storm-time TEC for low latitudes, while MIDAS is 13.44 % more accurate than ANN for the mid-latitudes. When their performances are compared with the IRI model, both MIDAS and ANN model were found to provide more accurate storm-time TEC reconstructions for the African low- and mid-latitude regions. A comparative study of the performances of EOF, NLRA, ANN, and IRI models to estimate TEC during geomagnetic storm conditions over various latitudes showed that the ANN model is about 10 %, 26 %, and 58 % more accurate than EOF, NLRA, and IRI models, respectively, while EOF was found to perform 15 %, and 44 % better than NLRA and IRI, respectively. It was further found that the NLRA model is 25 % more accurate than the IRI model. We have also investigated for the first time, the role of meridional neutral winds (from the Horizontal Wind Model) to storm-time TEC modelling in the low latitude, northern and southern hemisphere mid-latitude regions of the African sector, based on ANN models. Statistics have shown that the inclusion of the meridional wind velocity in TEC modelling during geomagnetic storms leads to percentage improvements of about 5 % for the low latitude, 10 % and 5 % for the northern and southern hemisphere mid-latitude regions, respectively. High-latitude storm-induced winds and the inter-hemispheric blows of the meridional winds from summer to winter hemisphere have been suggested to be associated with these improvements.
- Full Text:
- Date Issued: 2019
Muscle nanostructure, fat colour related fatty acids and Check-All-That-Apply visual profiling of South African A2 beef longissimus
- Authors: Soji, Zimkhitha
- Date: 2019
- Subjects: Meat -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15264 , vital:40332
- Description: The main objective of this study was to determine the effect of muscle nanostructure on tenderness, fat colour related fatty acids and Check-All-That-Apply visual profiling of South African A2 beef longissimus. Fifty two A-class steers (n=52) of five breeds (Bonsmara (n=19), Beef master (n=7), Hereford (n=9) and Simbra (n=17)) typically processed in different South African feedlots were studied. The animals were humanely slaughtered at an abattoir following the commercial standard procedures. Fat colour measurements (CIE b*) were taken at the P8 site on hot carcasses at the abattoir. Carcass mass (warm and cold) was recorded at the slaughter line before chilling (warm) and after chilling (cold) while pH0 and temperature were measured at 45 minutes post-mortem on the Longissimus thoracis et lumborum (LTL) muscle. Thereafter, a 20 g subsection of the LTL muscle on the left side of each carcass was sampled for muscle nanostructure analysis. At 24 hours post-slaughter, ultimate pH (pH24) was measured, further subsections of the LTL muscle (20 g) were harvested for further muscle nanostructure analysis and 2.5 kg of the LTL muscle was also harvested for analysis of tenderness, fatty acids and sensory evaluation. The muscle nanostructure (myofibril diameter (MYD), myofibril spacing (MYS), muscle fibre diameter (MFD), muscle fibre spacing (MFS) and sarcomere length (SL)) was analysed using the scanning electron microscope (SEM) while tenderness was measured using Warner Bratzler Shear Force after 45mins, 24hrs, 3 and 7 days aging period at -20 ºC refrigerator temperature. Some proximate fractions (total extractable intramuscular fat (Fat %), Fat Free Dry matter (FFDM %) and Moisture content) and fatty acid profile were measured using extracted fat and fatty acid indices (desaturase index, atherogenicity index) were calculated. Lastly a Check-All-That-Apply visual profiling method rated by an 80-member consumer panel was done to assess consumer meat preferences and perceptions of Bonsmara, Hereford and Simbra A2 fresh steaks. At 45mins post-slaughter breed affected (P<0.05) MYD and MYS, while at 24hrs breed affected MFD and MFS only. Early post-mortem pH (pH0) had no effect on the muscle nanostructure and tenderness while ultimate pH (pH24) affected MYD and MYS only. Muscle temperature at 45mins affected (P<0.05) the MYD, MFD and MFS, while 24hrs muscle temperature affected (P<0.05) MYD only. Tenderness was not related to the muscle nanostructure early post-mortem and there was no uniformity on the changes in muscle nanostructure and tenderness from early post-mortem to 24hrs against the multifaceted carcass mass, muscle pH and temperature effects. During ageing, breed affected the MYD and MYS at 45mins, while at 24hrs in addition to the myofibril structure breed also had an effect on muscle fibre bundle characteristics (MFD and MFS). The changes in MYD, MYS and MFS became constant on day 3 while variations in the MFD still progressed. There was no uniformity on the SL pattern during ageing and a very weak linear relationship between tenderness, SL, MFD and MFS was observed. Notably there was also no uniformity on how the muscle texture features; including the surface structure, fibre separation, and the mechanism of muscle contraction and relaxation; changed throughout the ageing period across and within the breeds. Moreover, breed had a significant effect on pentadecyclic acid, total saturated fatty acids (SFA) and docosahexanoic acid. Differences (P<0.05) in SFA, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), n-6, n-3, fatty acid ratios, and desaturase index were observed among the white, creamy-white and creamy fat colour. The distribution of fatty acid classes was SFA>MUFA>PUFA in descending order of concentrations of mean values (44.19:40.06:15.75, respectively), while the n-6: n-3 ratio was 12:1. In sensory evaluation, consumers indicated how they would prefer to pay premium for meat with guaranteed muscle and fat colour, low fat content, high marbling and tenderness. Consumers observed breed differences (P<0.05) in muscle fibre separation and muscle colour. The overall liking of each attribute was more on moderate bright cherry red lean colour, moderate yellow fat, very abundant marbling and slight separation of muscle fibres. Differences on discrete liking of each attribute among consumers had an effect on the overall liking of each steak with Hereford steaks being more preferred by consumers. It was concluded that meat from beef animals within the same feeding regime has a different fatty acid composition owing to different breed synthetic pathways and feed ingredients and that meat tenderness is not affected by the muscle nanostructure early post-mortem. However, during ageing, meat tenderness is directly linked to breed related myofibril structure changes in particular the myofibril diameter, spacing between myofibrils and their interaction; while the muscle texture features, fibre diameter, spacing between muscle fibres and sarcomere length explain the non-uniformity of beef tenderness. Also the organoleptic and health related quality of meat assumed more importance among consumers in sensory evaluation. Thus meat classification systems should include more credence aspects or indicators that support credence quality of meat
- Full Text:
- Date Issued: 2019
- Authors: Soji, Zimkhitha
- Date: 2019
- Subjects: Meat -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15264 , vital:40332
- Description: The main objective of this study was to determine the effect of muscle nanostructure on tenderness, fat colour related fatty acids and Check-All-That-Apply visual profiling of South African A2 beef longissimus. Fifty two A-class steers (n=52) of five breeds (Bonsmara (n=19), Beef master (n=7), Hereford (n=9) and Simbra (n=17)) typically processed in different South African feedlots were studied. The animals were humanely slaughtered at an abattoir following the commercial standard procedures. Fat colour measurements (CIE b*) were taken at the P8 site on hot carcasses at the abattoir. Carcass mass (warm and cold) was recorded at the slaughter line before chilling (warm) and after chilling (cold) while pH0 and temperature were measured at 45 minutes post-mortem on the Longissimus thoracis et lumborum (LTL) muscle. Thereafter, a 20 g subsection of the LTL muscle on the left side of each carcass was sampled for muscle nanostructure analysis. At 24 hours post-slaughter, ultimate pH (pH24) was measured, further subsections of the LTL muscle (20 g) were harvested for further muscle nanostructure analysis and 2.5 kg of the LTL muscle was also harvested for analysis of tenderness, fatty acids and sensory evaluation. The muscle nanostructure (myofibril diameter (MYD), myofibril spacing (MYS), muscle fibre diameter (MFD), muscle fibre spacing (MFS) and sarcomere length (SL)) was analysed using the scanning electron microscope (SEM) while tenderness was measured using Warner Bratzler Shear Force after 45mins, 24hrs, 3 and 7 days aging period at -20 ºC refrigerator temperature. Some proximate fractions (total extractable intramuscular fat (Fat %), Fat Free Dry matter (FFDM %) and Moisture content) and fatty acid profile were measured using extracted fat and fatty acid indices (desaturase index, atherogenicity index) were calculated. Lastly a Check-All-That-Apply visual profiling method rated by an 80-member consumer panel was done to assess consumer meat preferences and perceptions of Bonsmara, Hereford and Simbra A2 fresh steaks. At 45mins post-slaughter breed affected (P<0.05) MYD and MYS, while at 24hrs breed affected MFD and MFS only. Early post-mortem pH (pH0) had no effect on the muscle nanostructure and tenderness while ultimate pH (pH24) affected MYD and MYS only. Muscle temperature at 45mins affected (P<0.05) the MYD, MFD and MFS, while 24hrs muscle temperature affected (P<0.05) MYD only. Tenderness was not related to the muscle nanostructure early post-mortem and there was no uniformity on the changes in muscle nanostructure and tenderness from early post-mortem to 24hrs against the multifaceted carcass mass, muscle pH and temperature effects. During ageing, breed affected the MYD and MYS at 45mins, while at 24hrs in addition to the myofibril structure breed also had an effect on muscle fibre bundle characteristics (MFD and MFS). The changes in MYD, MYS and MFS became constant on day 3 while variations in the MFD still progressed. There was no uniformity on the SL pattern during ageing and a very weak linear relationship between tenderness, SL, MFD and MFS was observed. Notably there was also no uniformity on how the muscle texture features; including the surface structure, fibre separation, and the mechanism of muscle contraction and relaxation; changed throughout the ageing period across and within the breeds. Moreover, breed had a significant effect on pentadecyclic acid, total saturated fatty acids (SFA) and docosahexanoic acid. Differences (P<0.05) in SFA, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), n-6, n-3, fatty acid ratios, and desaturase index were observed among the white, creamy-white and creamy fat colour. The distribution of fatty acid classes was SFA>MUFA>PUFA in descending order of concentrations of mean values (44.19:40.06:15.75, respectively), while the n-6: n-3 ratio was 12:1. In sensory evaluation, consumers indicated how they would prefer to pay premium for meat with guaranteed muscle and fat colour, low fat content, high marbling and tenderness. Consumers observed breed differences (P<0.05) in muscle fibre separation and muscle colour. The overall liking of each attribute was more on moderate bright cherry red lean colour, moderate yellow fat, very abundant marbling and slight separation of muscle fibres. Differences on discrete liking of each attribute among consumers had an effect on the overall liking of each steak with Hereford steaks being more preferred by consumers. It was concluded that meat from beef animals within the same feeding regime has a different fatty acid composition owing to different breed synthetic pathways and feed ingredients and that meat tenderness is not affected by the muscle nanostructure early post-mortem. However, during ageing, meat tenderness is directly linked to breed related myofibril structure changes in particular the myofibril diameter, spacing between myofibrils and their interaction; while the muscle texture features, fibre diameter, spacing between muscle fibres and sarcomere length explain the non-uniformity of beef tenderness. Also the organoleptic and health related quality of meat assumed more importance among consumers in sensory evaluation. Thus meat classification systems should include more credence aspects or indicators that support credence quality of meat
- Full Text:
- Date Issued: 2019
Nonlinear optical responses of targeted phthalocyanines when conjugated with nanomaterials or fabricated into polymer thin films
- Authors: Nwaji, Njemuwa Njoku
- Date: 2019
- Subjects: Electrochemistry , Phthalocyanines , Nanoparticles , Bioconjugates , Thin films , Polymers , Nonlinear optics , Nonlinear optical spectroscopy , Nanostructured materials , Raman effect
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/71625 , vital:29926
- Description: A number of zinc, gallium and indium metallophthalocyanines (MPcs) with diverse substituents have been synthesized and characterized using various characterization tools such as proton nuclear magnetic resonance (1HNMR), matrix assisted laser desorption time of flight (MALDI-TOF) mass spectrometry, Fourier-transformed infra-red (FT-IR), Ultraviolet-visible (Uv-vis) spectrophotometry, magnetic circular dichroism and CHNS elemental analysis. The time dependent density functional theory was employed to probe the origin of spectroscopic information in these complexes. Complexes with gallium and indium as central metal showed higher triplet quantum yield compared to the zinc derivatives. Some of the MPcs were covalently linked to nanomaterials such as CdTe, CdTeSe, CdTeSe/ZnO, graphene quantum dots (GQDs) as well as metallic gold (AuNPs) and silver (AgNPs) nanoparticles. Others were either surface assembled onto AuNPs and AgNPs or embedded into polystyrene as polymer source. The phthalocyanine-nanomaterial composites (Pc-NMCs) were characterized with FT-IR, UV-visible spectrophotometry, transmission electron microscopy (TEM), dynamic light scattering (DLS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffractometry (XRD). The thickness of the thin films was determined by utilization of the knife edge attachment of the A Bruker D8 Discover X-ray diffraction. The optical limiting properties (using the open-aperture Z-scan technique) of the MPcs and the Pc-NMCs were investigated. The investigated MPcs complexes generally showed good optical limiting properties. The nonlinear optical response of the MPcs were improved in the presence of nanomaterials such as the semiconductor quantum dots (SQDs), graphene quantum dots (GQDs) as well as metallic AuNPs and AgNPs with MPc-QDs showing the best optical limiting behavior. The optical limiting properties of the MPcs were greatly enhanced in the presence of polymer thin films.
- Full Text:
- Date Issued: 2019
- Authors: Nwaji, Njemuwa Njoku
- Date: 2019
- Subjects: Electrochemistry , Phthalocyanines , Nanoparticles , Bioconjugates , Thin films , Polymers , Nonlinear optics , Nonlinear optical spectroscopy , Nanostructured materials , Raman effect
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/71625 , vital:29926
- Description: A number of zinc, gallium and indium metallophthalocyanines (MPcs) with diverse substituents have been synthesized and characterized using various characterization tools such as proton nuclear magnetic resonance (1HNMR), matrix assisted laser desorption time of flight (MALDI-TOF) mass spectrometry, Fourier-transformed infra-red (FT-IR), Ultraviolet-visible (Uv-vis) spectrophotometry, magnetic circular dichroism and CHNS elemental analysis. The time dependent density functional theory was employed to probe the origin of spectroscopic information in these complexes. Complexes with gallium and indium as central metal showed higher triplet quantum yield compared to the zinc derivatives. Some of the MPcs were covalently linked to nanomaterials such as CdTe, CdTeSe, CdTeSe/ZnO, graphene quantum dots (GQDs) as well as metallic gold (AuNPs) and silver (AgNPs) nanoparticles. Others were either surface assembled onto AuNPs and AgNPs or embedded into polystyrene as polymer source. The phthalocyanine-nanomaterial composites (Pc-NMCs) were characterized with FT-IR, UV-visible spectrophotometry, transmission electron microscopy (TEM), dynamic light scattering (DLS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffractometry (XRD). The thickness of the thin films was determined by utilization of the knife edge attachment of the A Bruker D8 Discover X-ray diffraction. The optical limiting properties (using the open-aperture Z-scan technique) of the MPcs and the Pc-NMCs were investigated. The investigated MPcs complexes generally showed good optical limiting properties. The nonlinear optical response of the MPcs were improved in the presence of nanomaterials such as the semiconductor quantum dots (SQDs), graphene quantum dots (GQDs) as well as metallic AuNPs and AgNPs with MPc-QDs showing the best optical limiting behavior. The optical limiting properties of the MPcs were greatly enhanced in the presence of polymer thin films.
- Full Text:
- Date Issued: 2019
Nutritional quality of sausage made with edible meat waste and the perception of consumers on offal product in Eastern Cape Province, South Africa
- Authors: Oluwasegun, Babatunde Alao
- Date: 2019
- Subjects: Meat -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/19021 , vital:40094
- Description: Meat processing at the abattoir provides meat by product and waste while, the major part of the muscle which constitutes a third is edible. The edible by products (EBP) of meat have a notable position in our day-to-day life and are used in diverse forms. However, the quality of offal meat may differ according to intrinsic and extrinsic attributes that may occasionally be shaped by the attitude of consumers towards the products. Therefore, the first objective of this thesis focused on features that might influence consumer preferences and their perception of offal meat. A total of 202 consumers from three Municipalities in Amathole District were randomly sampled using exponential nondiscriminative snowball sampling. Data were gathered through a structured questionnaire containing open ended and closed ended questions. The study showed that consumers were more influenced by the freshness, price and availability of the product and these factors are used to determine the purchase outlet. Differences were observed in the offal meat consumption between the age groups. Age groups 25-34 (29.7%) and 35-44 (27.4%) showed the highest offal meat consumption, while the decline was observed in age groups of 55-64 (11.9%), 65- 74 (5.9%) and 75-85 (0.01%) respectively. The most preferred purchase point for offal meat in this study was in butcheries. However, it was observed that the factors influencing offal consumption in Amathole District were similar to meat consumption except that, offals were mainly purchased at butcher shops. The second objective in this study was to determine the sensory characteristics and consumer acceptance of sausages with 10% fat, 30% edible meat waste and 50% edible meat waste. Sensory descriptive attributes such as appearance, texture, colour, taste, flavour and overall acceptance of the sausage were evaluated by sensory panel (n = 60). The sensory panel comprised of students from undergraduates, post-graduates, post-doctoral fellows and lecturers at the University of Fort Hare. The findings of the study indicated that 50% replacement of xiii edible meat waste was similar to the commercial 10% fat with regard to several sensory attributes and pooled liking. Therefore, the utilization of the edible meat waste in production of sausages has the potential to increase profitability in meat industry and minimise meat waste in the industry. However, the cooking method that was more acceptable to consumers in this study was using the microwave as compared to oven-grilling. Furthermore, the effects of different cooking methods (microwave and oven-grilling) on proximate and mineral composition of the formulated sausages were determined. However, the cooking process appeared to have a significant effect on most of the minerals in the sausage. The cooking methods had a significant effect at P <0.01 on the nutrients composition of the formulated sausage. It was observed that the nutritional values of the sausage was better preserved after the cooking process due to higher mean values obtained after cooking. The mean values for calcium (173.1, 221.76, 231.29), potassium (444.57, 158.58, 156.67), magnesium (84.43, 257.97, 127.27), zinc (52.94, 35.27, 27.13), copper (8.8, 7.07, 4.44), manganese (8.74, 0.65, 0.08), sodium (589.42, 604.45, 529.79) and iron (63.3, 85.38, 74.81) in cooked. And the mean values for calcium (286.18, 132.18, 114.79), potassium (206.64, 113.83, 207.81), magnesium (189.89, 33.97, 48.11), zinc (61.05, 28.09, 26.44), copper (2.92, 2.73, 3.89), manganese (1.42, 0.11, 0.35), sodium (566.47, 530.79, 527.35) and iron (77.56, 58.68, 45.42) in uncooked sausage varied greatly among the treatments. Although, the disparities in the mineral content may be attributed to the different edible meat waste from different parts of the cattle which are either from feedlot or pastured based. In regard to the results obtained from proximate and mineral composition, microwave cooking method was found to be the best cooking technique for healthy eating. Finally, the effect of frying with two different oils (sunflower oil and olive oil) on the fatty acid composition of sausage made with edible meat waste was examined. The results revealed that beef sausage containing 70% edible meat wastes and 30% beef (T1) had a higher fat content xiv (25.7%±0.83%) than other treatments. On the other hand, beef sausage fortified with 10% fat and 90% beef (T3) had the lowest fat content but highest FFDM (55.85±0.57%) and moisture content (69.15±0.62) than other treatments. Despite the increase in omega-3: omega-6 fatty acid ratio in the sausage treatments after cooking, the mean value of omega-3: omega-6 fatty acid ratio was greater than 1:5 (0.2) which is within the FAO/WHO recommended range. The omega-3: omega-6 association is well-known for its importance in the diet because it is a key factor for balanced eicosanoid production in the living organism. The significant reduction in saturated fatty acids after cooking showed that there could also be a positive influence on the human health if consumed. Therefore, it may be concluded from the findings of the study that sausage made with edible meat waste as fat replacer is safe for human consumption.
- Full Text:
- Date Issued: 2019
- Authors: Oluwasegun, Babatunde Alao
- Date: 2019
- Subjects: Meat -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/19021 , vital:40094
- Description: Meat processing at the abattoir provides meat by product and waste while, the major part of the muscle which constitutes a third is edible. The edible by products (EBP) of meat have a notable position in our day-to-day life and are used in diverse forms. However, the quality of offal meat may differ according to intrinsic and extrinsic attributes that may occasionally be shaped by the attitude of consumers towards the products. Therefore, the first objective of this thesis focused on features that might influence consumer preferences and their perception of offal meat. A total of 202 consumers from three Municipalities in Amathole District were randomly sampled using exponential nondiscriminative snowball sampling. Data were gathered through a structured questionnaire containing open ended and closed ended questions. The study showed that consumers were more influenced by the freshness, price and availability of the product and these factors are used to determine the purchase outlet. Differences were observed in the offal meat consumption between the age groups. Age groups 25-34 (29.7%) and 35-44 (27.4%) showed the highest offal meat consumption, while the decline was observed in age groups of 55-64 (11.9%), 65- 74 (5.9%) and 75-85 (0.01%) respectively. The most preferred purchase point for offal meat in this study was in butcheries. However, it was observed that the factors influencing offal consumption in Amathole District were similar to meat consumption except that, offals were mainly purchased at butcher shops. The second objective in this study was to determine the sensory characteristics and consumer acceptance of sausages with 10% fat, 30% edible meat waste and 50% edible meat waste. Sensory descriptive attributes such as appearance, texture, colour, taste, flavour and overall acceptance of the sausage were evaluated by sensory panel (n = 60). The sensory panel comprised of students from undergraduates, post-graduates, post-doctoral fellows and lecturers at the University of Fort Hare. The findings of the study indicated that 50% replacement of xiii edible meat waste was similar to the commercial 10% fat with regard to several sensory attributes and pooled liking. Therefore, the utilization of the edible meat waste in production of sausages has the potential to increase profitability in meat industry and minimise meat waste in the industry. However, the cooking method that was more acceptable to consumers in this study was using the microwave as compared to oven-grilling. Furthermore, the effects of different cooking methods (microwave and oven-grilling) on proximate and mineral composition of the formulated sausages were determined. However, the cooking process appeared to have a significant effect on most of the minerals in the sausage. The cooking methods had a significant effect at P <0.01 on the nutrients composition of the formulated sausage. It was observed that the nutritional values of the sausage was better preserved after the cooking process due to higher mean values obtained after cooking. The mean values for calcium (173.1, 221.76, 231.29), potassium (444.57, 158.58, 156.67), magnesium (84.43, 257.97, 127.27), zinc (52.94, 35.27, 27.13), copper (8.8, 7.07, 4.44), manganese (8.74, 0.65, 0.08), sodium (589.42, 604.45, 529.79) and iron (63.3, 85.38, 74.81) in cooked. And the mean values for calcium (286.18, 132.18, 114.79), potassium (206.64, 113.83, 207.81), magnesium (189.89, 33.97, 48.11), zinc (61.05, 28.09, 26.44), copper (2.92, 2.73, 3.89), manganese (1.42, 0.11, 0.35), sodium (566.47, 530.79, 527.35) and iron (77.56, 58.68, 45.42) in uncooked sausage varied greatly among the treatments. Although, the disparities in the mineral content may be attributed to the different edible meat waste from different parts of the cattle which are either from feedlot or pastured based. In regard to the results obtained from proximate and mineral composition, microwave cooking method was found to be the best cooking technique for healthy eating. Finally, the effect of frying with two different oils (sunflower oil and olive oil) on the fatty acid composition of sausage made with edible meat waste was examined. The results revealed that beef sausage containing 70% edible meat wastes and 30% beef (T1) had a higher fat content xiv (25.7%±0.83%) than other treatments. On the other hand, beef sausage fortified with 10% fat and 90% beef (T3) had the lowest fat content but highest FFDM (55.85±0.57%) and moisture content (69.15±0.62) than other treatments. Despite the increase in omega-3: omega-6 fatty acid ratio in the sausage treatments after cooking, the mean value of omega-3: omega-6 fatty acid ratio was greater than 1:5 (0.2) which is within the FAO/WHO recommended range. The omega-3: omega-6 association is well-known for its importance in the diet because it is a key factor for balanced eicosanoid production in the living organism. The significant reduction in saturated fatty acids after cooking showed that there could also be a positive influence on the human health if consumed. Therefore, it may be concluded from the findings of the study that sausage made with edible meat waste as fat replacer is safe for human consumption.
- Full Text:
- Date Issued: 2019
Observing cosmic reionization with PAPER: polarized foreground simulations and all sky images
- Authors: Nunhokee, Chuneeta Devi
- Date: 2019
- Subjects: Cosmic background radiation , Astronomy -- Observations , Epoch of reionization -- Research , Hydrogen -- Spectra , Radio interferometers
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/68203 , vital:29218
- Description: The Donald C. Backer Precision Array to Probe the Epoch of Reionization (PAPER, Parsons et al., 2010) was built with an aim to detect the redshifted 21 cm Hydrogen line, which is likely the best probe of thermal evolution of the intergalactic medium and reionization of neutral Hydrogen in our Universe. Observations of the 21 cm signal are challenged by bright astrophysical foregrounds and systematics that require precise modeling in order to extract the cosmological signal. In particular, the instrumental leakage of polarized foregrounds may contaminate the 21 cm power spectrum. In this work, we developed a formalism to describe the leakage due to instrumental widefield effects in visibility-based power spectra and used it to predict contaminations in observations. We find the leakage due to a population of point sources to be higher than the diffuse Galactic emission – for which we can predict minimal contaminations at k>0.3 h Mpc -¹ We also analyzed data from the last observing season of PAPER via all-sky imaging with a view to characterize the foregrounds. We generated an all-sky catalogue of 88 sources down to a flux density of 5 Jy. Moreover, we measured both polarized point source and the Galactic diffuse emission, and used these measurements to constrain our model of polarization leakage. We find the leakage due to a population of point sources to be 12% lower than the prediction from our polarized model.
- Full Text:
- Date Issued: 2019
- Authors: Nunhokee, Chuneeta Devi
- Date: 2019
- Subjects: Cosmic background radiation , Astronomy -- Observations , Epoch of reionization -- Research , Hydrogen -- Spectra , Radio interferometers
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/68203 , vital:29218
- Description: The Donald C. Backer Precision Array to Probe the Epoch of Reionization (PAPER, Parsons et al., 2010) was built with an aim to detect the redshifted 21 cm Hydrogen line, which is likely the best probe of thermal evolution of the intergalactic medium and reionization of neutral Hydrogen in our Universe. Observations of the 21 cm signal are challenged by bright astrophysical foregrounds and systematics that require precise modeling in order to extract the cosmological signal. In particular, the instrumental leakage of polarized foregrounds may contaminate the 21 cm power spectrum. In this work, we developed a formalism to describe the leakage due to instrumental widefield effects in visibility-based power spectra and used it to predict contaminations in observations. We find the leakage due to a population of point sources to be higher than the diffuse Galactic emission – for which we can predict minimal contaminations at k>0.3 h Mpc -¹ We also analyzed data from the last observing season of PAPER via all-sky imaging with a view to characterize the foregrounds. We generated an all-sky catalogue of 88 sources down to a flux density of 5 Jy. Moreover, we measured both polarized point source and the Galactic diffuse emission, and used these measurements to constrain our model of polarization leakage. We find the leakage due to a population of point sources to be 12% lower than the prediction from our polarized model.
- Full Text:
- Date Issued: 2019
Occurrence, feeding ecology, and population structure of two dolphin species, Tursiops aduncus and Delphinus delphis, off the Wild Coast of South Africa
- Authors: Caputo, Michelle Anne
- Date: 2019
- Subjects: Delphinus -- South Africa-- Kwazulu-Natal -- Ecology , Tursoops -- South Africa-- Kwazulu-Natal -- Ecology , Delphinus -- South Africa-- Kwazulu-Natal -- Feeding and feeds , Tursoops -- South Africa-- Kwazulu-Natal -- Feeding and feeds , Dolphins -- South Africa-- Kwazulu-Natal , Delphinus -- South Africa-- Kwazulu-Natal -- Behavior , Tursoops -- South Africa-- Kwazulu-Natal -- Behavior , Marine ecology -- South Africa -- Kwazulu-Natal
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115612 , vital:34197
- Description: Dolphins are apex predators and their movements, foraging activities and population dynamics play an important role in shaping their environment. Understanding their occurrence, movement patterns, and trophic ecology is essential to their conservation, especially as they are considered sentinel species. The Wild Coast of South Africa’s Eastern Cape, is characterized by the annual sardine (Sardinops sagax) run, which serves as an important foraging event for apex predators, including Indo-Pacific bottlenose (Tursiops aduncus) and long-beaked common dolphins (Delphinus delphis). Despite the ecological significance of this event, no dedicated surveys for these species have previously been conducted in this area. The main objectives of this research were to: investigate long-term occurrence of dolphins during the sardine run to determine if there have been any changes over the past 19 years, as has been predicted from common dolphin dietary investigations and anecdotal evidence; to determine short-term occurrence and movement patterns of selected inshore delphinids within the area, which is characterized by three marine protected areas (MPAs); and to use stable isotope analyses to determine trophic relationships and population structure of bottlenose and common dolphins within the region. Long-term data consisted of 131 opportunistic aerial surveys conducted between May and July over the period 1996 to 2014. Results from these surveys indicate that common dolphins, typically associated with sardines, decreased significantly in average group size over the study period (p=0.0343). Bottlenose dolphins, demonstrated no such trend (p=0.916). For both species, greater majority (> 70% of total counts) of sightings were made inside the MPAs. Short-term boat-based surveys were conducted three times a year between June 2014 and December 2016, contributing to a total of 47 days of surveys divided into three locations: Amathole, Hluleka, and Pondoland, each containing a MPA. Density and group size data were analyzed for both species and photographic identification analysis was performed for photographs of bottlenose dolphin dorsal fins. Results indicate that animal and sighting density did not differ temporally (bottlenose dolphin: sighting density – p=0.398, individual density –p=0.781; common dolphin: sighting density –p=0.472, individual density – p=0.204). Environmental factors (sea surface temperature, depth, substrate, and distance from shore) appeared to have limited effect on individual and sighting density and group size for both species (p>0.05). Photographic identification of bottlenose dolphins resulted in 2149 individuals, with a 11.8% resighting rate, with the highest resighting rate within the Pondoland MPA (16.1%). The resighting count did not differ temporally between monthly survey based on generalized linear models (p=0.866), but did differ between study areas (p<0.0001). These results provide the first evidence of the occurrence of both species of dolphin off the Wild Coast, as they were sighted in this region in all survey months. There was no trend in density based on temporal or environmental factors, which suggests other factors are influencing their occurrence. Resightings of bottlenose dolphins within the area suggest that there is some degree of residency, though the majority of animals were only sighted on a single occasion and there was no plateau in the discovery curve. A total of 256 biopsy samples (bottlenose dolphins =128; common dolphins=128) were collected during boat-based surveys. Bottlenose dolphin samples were also collected from adjacent areas to the southwest (Algoa Bay, n=22) and northeast (KwaZulu-Natal (KZN), n=20) of the Wild Coast to investigate similarities and differences between these areas. Despite a high degree of niche overlap between the two species (41%), common dolphins fed with a broader niche (standard ellipse area probability 0.89) than bottlenose dolphins in the summer and a narrower niche in the winter (probability 0.94). There was a clear spatial variation in the diet of bottlenose dolphins along the coast, with individuals from Algoa Bay and Amathole demonstrating 0% niche overlap with individuals from KZN, but the mechanism for these differences remains unclear as other species from South African waters demonstrate a strong southwest to northeast gradient in nitrogen for the Eastern Cape coastline. This research provides valuable baseline information regarding dolphins off the Wild Coast of South Africa, which remained largely unknown. My results indicate that bottlenose dolphins may be more resident in the Wild Coast than previous predicted, and confirm that common dolphins are highly mobile in this area.
- Full Text:
- Date Issued: 2019
- Authors: Caputo, Michelle Anne
- Date: 2019
- Subjects: Delphinus -- South Africa-- Kwazulu-Natal -- Ecology , Tursoops -- South Africa-- Kwazulu-Natal -- Ecology , Delphinus -- South Africa-- Kwazulu-Natal -- Feeding and feeds , Tursoops -- South Africa-- Kwazulu-Natal -- Feeding and feeds , Dolphins -- South Africa-- Kwazulu-Natal , Delphinus -- South Africa-- Kwazulu-Natal -- Behavior , Tursoops -- South Africa-- Kwazulu-Natal -- Behavior , Marine ecology -- South Africa -- Kwazulu-Natal
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115612 , vital:34197
- Description: Dolphins are apex predators and their movements, foraging activities and population dynamics play an important role in shaping their environment. Understanding their occurrence, movement patterns, and trophic ecology is essential to their conservation, especially as they are considered sentinel species. The Wild Coast of South Africa’s Eastern Cape, is characterized by the annual sardine (Sardinops sagax) run, which serves as an important foraging event for apex predators, including Indo-Pacific bottlenose (Tursiops aduncus) and long-beaked common dolphins (Delphinus delphis). Despite the ecological significance of this event, no dedicated surveys for these species have previously been conducted in this area. The main objectives of this research were to: investigate long-term occurrence of dolphins during the sardine run to determine if there have been any changes over the past 19 years, as has been predicted from common dolphin dietary investigations and anecdotal evidence; to determine short-term occurrence and movement patterns of selected inshore delphinids within the area, which is characterized by three marine protected areas (MPAs); and to use stable isotope analyses to determine trophic relationships and population structure of bottlenose and common dolphins within the region. Long-term data consisted of 131 opportunistic aerial surveys conducted between May and July over the period 1996 to 2014. Results from these surveys indicate that common dolphins, typically associated with sardines, decreased significantly in average group size over the study period (p=0.0343). Bottlenose dolphins, demonstrated no such trend (p=0.916). For both species, greater majority (> 70% of total counts) of sightings were made inside the MPAs. Short-term boat-based surveys were conducted three times a year between June 2014 and December 2016, contributing to a total of 47 days of surveys divided into three locations: Amathole, Hluleka, and Pondoland, each containing a MPA. Density and group size data were analyzed for both species and photographic identification analysis was performed for photographs of bottlenose dolphin dorsal fins. Results indicate that animal and sighting density did not differ temporally (bottlenose dolphin: sighting density – p=0.398, individual density –p=0.781; common dolphin: sighting density –p=0.472, individual density – p=0.204). Environmental factors (sea surface temperature, depth, substrate, and distance from shore) appeared to have limited effect on individual and sighting density and group size for both species (p>0.05). Photographic identification of bottlenose dolphins resulted in 2149 individuals, with a 11.8% resighting rate, with the highest resighting rate within the Pondoland MPA (16.1%). The resighting count did not differ temporally between monthly survey based on generalized linear models (p=0.866), but did differ between study areas (p<0.0001). These results provide the first evidence of the occurrence of both species of dolphin off the Wild Coast, as they were sighted in this region in all survey months. There was no trend in density based on temporal or environmental factors, which suggests other factors are influencing their occurrence. Resightings of bottlenose dolphins within the area suggest that there is some degree of residency, though the majority of animals were only sighted on a single occasion and there was no plateau in the discovery curve. A total of 256 biopsy samples (bottlenose dolphins =128; common dolphins=128) were collected during boat-based surveys. Bottlenose dolphin samples were also collected from adjacent areas to the southwest (Algoa Bay, n=22) and northeast (KwaZulu-Natal (KZN), n=20) of the Wild Coast to investigate similarities and differences between these areas. Despite a high degree of niche overlap between the two species (41%), common dolphins fed with a broader niche (standard ellipse area probability 0.89) than bottlenose dolphins in the summer and a narrower niche in the winter (probability 0.94). There was a clear spatial variation in the diet of bottlenose dolphins along the coast, with individuals from Algoa Bay and Amathole demonstrating 0% niche overlap with individuals from KZN, but the mechanism for these differences remains unclear as other species from South African waters demonstrate a strong southwest to northeast gradient in nitrogen for the Eastern Cape coastline. This research provides valuable baseline information regarding dolphins off the Wild Coast of South Africa, which remained largely unknown. My results indicate that bottlenose dolphins may be more resident in the Wild Coast than previous predicted, and confirm that common dolphins are highly mobile in this area.
- Full Text:
- Date Issued: 2019
Ontological Model for Xhosa Beadwork in Marginalised Rural Communities: A Case of the Eastern Cape
- Authors: Tinarwo, Loyd
- Date: 2019
- Subjects: Ontology Beadwork
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15749 , vital:40516
- Description: In South Africa, computational ontologies have gained traction and are increasingly viewed as one of the viable solutions to address the problem of fragmented and unstructured nature of indigenous knowledge (IK) particularly in the marginalized rural communities. The continual existence of IK in tacit form has impeded the use of IK as a potential resource that can catalyze socio-economic and cultural development in South Africa. This study was, therefore, designed to address part of this challenge by developing a Xhosa Beadwork Ontology (XBO) with the goal of structuring the domain knowledge into a reusable body of knowledge. Such a reusable body of knowledge promotes efficient sharing of a common understanding of Xhosa Beadwork in a computational form. The XBO is in OWL 2 DL. The development of the XBO was informed by the NeOn methodology and the iterativeincremental ontology development life cycle within the ambit of Action Research (AR). The XBO was developed around personal ornamentation Xhosa Beadwork consisting of Necklace, Headband, Armlet, Waistband, Bracelet, and Anklet. In this study, the XBO was evaluated focused on ascertaining that the created ontology is a comprehensive representation of the Xhosa Beadwork and is of the required standard. In addition, the XBO was documented into a human understandable and readable resource and was published. The outcome of the study has indicated that the XBO is an adequate, shareable and reusable semantic artifact that can indeed support the formalization and preservation of IK in the domain of Xhosa Beadwork
- Full Text:
- Date Issued: 2019
- Authors: Tinarwo, Loyd
- Date: 2019
- Subjects: Ontology Beadwork
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15749 , vital:40516
- Description: In South Africa, computational ontologies have gained traction and are increasingly viewed as one of the viable solutions to address the problem of fragmented and unstructured nature of indigenous knowledge (IK) particularly in the marginalized rural communities. The continual existence of IK in tacit form has impeded the use of IK as a potential resource that can catalyze socio-economic and cultural development in South Africa. This study was, therefore, designed to address part of this challenge by developing a Xhosa Beadwork Ontology (XBO) with the goal of structuring the domain knowledge into a reusable body of knowledge. Such a reusable body of knowledge promotes efficient sharing of a common understanding of Xhosa Beadwork in a computational form. The XBO is in OWL 2 DL. The development of the XBO was informed by the NeOn methodology and the iterativeincremental ontology development life cycle within the ambit of Action Research (AR). The XBO was developed around personal ornamentation Xhosa Beadwork consisting of Necklace, Headband, Armlet, Waistband, Bracelet, and Anklet. In this study, the XBO was evaluated focused on ascertaining that the created ontology is a comprehensive representation of the Xhosa Beadwork and is of the required standard. In addition, the XBO was documented into a human understandable and readable resource and was published. The outcome of the study has indicated that the XBO is an adequate, shareable and reusable semantic artifact that can indeed support the formalization and preservation of IK in the domain of Xhosa Beadwork
- Full Text:
- Date Issued: 2019
Patriarchy and the participation of women in Zimbabwean national politics: a study of selected women Politicians in Matabeleland Region
- Authors: Manyevere, Sithabile
- Date: 2019
- Subjects: Women politicians Women -- Political activity -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/17506 , vital:41082
- Description: The research sought to analyse how patriarchal perceptions have affected women in Zimbabwean national politics with specific focus on women politicians in Matabeleland region. The researcher observed that women politicians in this region seem to face multiple oppressions and yet seem to have been excluded in previous studies. The mixed method approach was adopted for the research. Questionnaires were used for the quantitative method, while key informant interviews and focus group discussions were utilised for the qualitative method. Findings from the survey revealed stereotypical perceptions such as that men are better leaders than women, women are not capable of holding decision making positions and the perception that politics is not safe for women. The findings from the key informants indicate that women politicians in Matabeleland face quite a number of challenges emanating from these patriarchal perceptions. The challenges include violence, humiliation and cultural stigmatization. Although women have attempted to resist patriarchy, it seems that the resistance has not been enough to eliminate the patriarchal mentality and the oppressions that accompany it. The research adopts a combination of feminist and intersectionality theory as a framework for analysis of the problem under investigation. The research potentially contributes to academic discourse by advancing literature on the multi-faceted aspects of patriarchy. The study recommends psychological and financial empowerment of women, electoral reforms and criminalization of offenders. The implementation of proper reforms and corrective measures envisage the long-awaited new dawn among women whom since time memorial, have been suppressed by deep-seated societal and patriarchal beliefs.
- Full Text:
- Date Issued: 2019
- Authors: Manyevere, Sithabile
- Date: 2019
- Subjects: Women politicians Women -- Political activity -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/17506 , vital:41082
- Description: The research sought to analyse how patriarchal perceptions have affected women in Zimbabwean national politics with specific focus on women politicians in Matabeleland region. The researcher observed that women politicians in this region seem to face multiple oppressions and yet seem to have been excluded in previous studies. The mixed method approach was adopted for the research. Questionnaires were used for the quantitative method, while key informant interviews and focus group discussions were utilised for the qualitative method. Findings from the survey revealed stereotypical perceptions such as that men are better leaders than women, women are not capable of holding decision making positions and the perception that politics is not safe for women. The findings from the key informants indicate that women politicians in Matabeleland face quite a number of challenges emanating from these patriarchal perceptions. The challenges include violence, humiliation and cultural stigmatization. Although women have attempted to resist patriarchy, it seems that the resistance has not been enough to eliminate the patriarchal mentality and the oppressions that accompany it. The research adopts a combination of feminist and intersectionality theory as a framework for analysis of the problem under investigation. The research potentially contributes to academic discourse by advancing literature on the multi-faceted aspects of patriarchy. The study recommends psychological and financial empowerment of women, electoral reforms and criminalization of offenders. The implementation of proper reforms and corrective measures envisage the long-awaited new dawn among women whom since time memorial, have been suppressed by deep-seated societal and patriarchal beliefs.
- Full Text:
- Date Issued: 2019
Perspectives on land and water politics at Mushandike Irrigation Scheme, Masvingo, Zimbabwe
- Authors: Mafukidze, Jonathan
- Date: 2019
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76479 , vital:30573
- Description: Access to, control and ownership of land and water, amongst other natural resources in Zimbabwe, shape and affect rural lives, livelihoods, social relations and social organisation. Rural poverty has been entrenched and exacerbated by, amongst other factors, highly restricted access to these scarce resources. Historically, Zimbabwe’s rural areas (such as communal areas, smallholder irrigation schemes and resettlement areas) have existed as sites of struggles where contestations and negotiations over access to, control or ownership of these resources have taken place. Resultantly, multifaceted and dynamic social relations have been weaved and contested social spaces carved out. In rural Zimbabwe, contestations have tended to be complex, nuanced and intricate, working themselves out in different ways across time and space. In their heightened and more visible state, they have been characterised by violent physical expressions which, in the history of the country, involved two wars of liberation, the First Chimurenga (1896-1897) and the Second Chimurenga (1960s to 1980). The most recent violent manifestation was through nation-wide land invasions, politically christened the Third Chimurenga, which peaked in 2000 and continued sporadically to this day. Few studies on smallholder irrigation schemes in Zimbabwe have focused on understanding how contestations for access to scarce land and water resources are framed and negotiated at the local level. Cognisant of this lacuna, this thesis uses social constructionism in examining, as a case study, Mushandike Smallholder Irrigation Scheme in Masvingo Province in order to understand and analyse how land and water politics occur at the local level. The study deploys a qualitative research methodology approach in examining local water and land politics, which involved original irrigation beneficiaries and more recent land invaders. Findings of the thesis indicate that land and water shortages have increased considerably in the past two decades at the irrigation scheme due to the influx of land invaders into the scheme. This influx has had a negative impact on agricultural production and other livelihood strategies. Both scheme members and land invaders lay claim to land and water at Mushandike. These claims are intricately constructed and contested, and they are linked to broader issues such as partisan party-politics, policy developments, and tradition, origin, indigeneity and belonging. Though the struggles over land and water at Mushandike are firmly rooted in the concrete conditions of existence and experiences of beneficiaries and land invaders, external actors such as political leaders, state bureaucrats and traditional chiefs tend to complicate and intensify the contestations.
- Full Text:
- Date Issued: 2019
- Authors: Mafukidze, Jonathan
- Date: 2019
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76479 , vital:30573
- Description: Access to, control and ownership of land and water, amongst other natural resources in Zimbabwe, shape and affect rural lives, livelihoods, social relations and social organisation. Rural poverty has been entrenched and exacerbated by, amongst other factors, highly restricted access to these scarce resources. Historically, Zimbabwe’s rural areas (such as communal areas, smallholder irrigation schemes and resettlement areas) have existed as sites of struggles where contestations and negotiations over access to, control or ownership of these resources have taken place. Resultantly, multifaceted and dynamic social relations have been weaved and contested social spaces carved out. In rural Zimbabwe, contestations have tended to be complex, nuanced and intricate, working themselves out in different ways across time and space. In their heightened and more visible state, they have been characterised by violent physical expressions which, in the history of the country, involved two wars of liberation, the First Chimurenga (1896-1897) and the Second Chimurenga (1960s to 1980). The most recent violent manifestation was through nation-wide land invasions, politically christened the Third Chimurenga, which peaked in 2000 and continued sporadically to this day. Few studies on smallholder irrigation schemes in Zimbabwe have focused on understanding how contestations for access to scarce land and water resources are framed and negotiated at the local level. Cognisant of this lacuna, this thesis uses social constructionism in examining, as a case study, Mushandike Smallholder Irrigation Scheme in Masvingo Province in order to understand and analyse how land and water politics occur at the local level. The study deploys a qualitative research methodology approach in examining local water and land politics, which involved original irrigation beneficiaries and more recent land invaders. Findings of the thesis indicate that land and water shortages have increased considerably in the past two decades at the irrigation scheme due to the influx of land invaders into the scheme. This influx has had a negative impact on agricultural production and other livelihood strategies. Both scheme members and land invaders lay claim to land and water at Mushandike. These claims are intricately constructed and contested, and they are linked to broader issues such as partisan party-politics, policy developments, and tradition, origin, indigeneity and belonging. Though the struggles over land and water at Mushandike are firmly rooted in the concrete conditions of existence and experiences of beneficiaries and land invaders, external actors such as political leaders, state bureaucrats and traditional chiefs tend to complicate and intensify the contestations.
- Full Text:
- Date Issued: 2019
Ph-responsive liposomal systems for site-specific pulmonary delivery of anti-tubercular drugs
- Nkanga, Christian Isalomboto
- Authors: Nkanga, Christian Isalomboto
- Date: 2019
- Subjects: Tuberculosis -- Chemotherapy , Lipsomes , Drug carriers (Pharmacy) , Rifampin , Hydrogen-ion concentration , Hydrogen-ion concentration -- Physiological effect
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/125832 , vital:35822
- Description: Tuberculosis (TB) is an infectious disease that has been reported to be the ninth leading cause of death worldwide, even though mostly considered as a poverty related disease. Despite the existence of potent anti-tubercular drugs (ATBDs), such as rifampicin (RIF) and isoniazid (INH), TB remains the major killer among many microbial diseases over the last five years. Although several factors are to be blamed for this deadly status, the most crucial issues encompass both the self-defensiveness of the causative agent (Mycobacterium tuberculosis), including its intra-macrophage location that compromises ATBDs accessibility, and the widespread/off target distribution of ATBDs. The need for novel drug delivery strategies therefore arises to provide selective distribution of ATBDs at the infected site. Among the drug vehicles explored in this field, liposomes have been reported to be the most suitable drug carriers due to their rapid uptake by alveolar macrophages, where M. tuberculosis often resides. Since liposomes experience media of different pH throughout the cell uptake process (endocytosis/phagocytosis), the use of pH change as a stimulus for controlled release looks promising for enhancing intra-macrophage delivery and minimizing premature ‘off-target’ release of ATBDs. However, the costly status of liposome technology, due to the use of sophisticated procedures and expensive materials (especially for pH-dependent delivery, where special lipids are required), may preclude wider developments of liposomal products, especially for the developing world. This study aimed at investigating liposomal encapsulation of pH-sensitive and fluorescent hydrazone derivatives of INH using crude soybean lecithin, as a cost-effective option for site-specific delivery combined with potential bio-imaging features. Another objective was to explore encapsulation of INH hydrazone derivatives with and without RIF in liposomes using a simple and organic solvent-free preparation method. Initially, INH was coupled with 4-hydroxy-benzaldehyde to yield a conjugate (INH-HB) that was encapsulated in liposomes using film hydration method with acceptable encapsulation efficiency (î), about 89 %. The prepared INH-HB loaded liposomes (IHL) were characterized by means of dynamic light scattering (DLS), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The release of INH from IHL was evaluated over 12 hours in media of different pH using dialysis. As hypothesized, pH dependent release of INH from IHL was observed with 22, 69, 83 and 100 % release obtained in media of pH 7.4, 6.4, 5.4 and 4.4, respectively. From this experimental trial, further development was undertaken by conjugating INH to a hydrophobic fluorescent tag, zinc (II) phthalocyanine (PC), through hydrazone linkages. The obtained conjugate (PC-INH) was loaded into liposomes (PIL) that were characterized using various spectroscopic techniques, including UV-Vis absorption and energy dispersive X-ray spectroscopy, which suggested the presence of PC-INH within the lipid bilayers. The release study performed in different pH media revealed 22, 41, 97 and 100 % of INH, respectively released at pH 7.4, 6.4, 5.4 and 4.4. This confirmed the potential of pH-triggered drug release from liposomes loaded with hydrazone drug derivatives. In addition, successful encapsulation of PC-INH using crude soybean lecithin inspired a new opening towards development of multimodal liposomes that could achieve controlled drug release with added benefits of image-guided biological tracking. However, the hydrophobic nature of PC-INH requires an effective strategy that could improve its solubility and favour extensive development. In this context, the tetra-substituted structure of PC-INH brought up the hypothesis that cyclodextrin (CD) complexation would facilitate PC-INH encapsulation in liposomes using an organic solvent-free method, called here the “heating method” (HM). Inclusion complexes of PC-INH with various CDs were therefore investigated, with gamma-CD complex (CP) giving the best results. These complexes were prepared in both solution and solid-state and further comprehensively characterized using UV-Vis spectroscopy, magnetic circular dichroism, NMR spectroscopy, diffusion ordered spectroscopy, DSC, XRD and Fourier transform infrared spectroscopy. CP-loaded liposomes prepared using HM exhibited greater î than film hydration liposomes, about 70 % versus 56 %, respectively. The HM-liposomal system (CPL) exhibited potentially useful nano particulate characteristics (i.e. mean particle size 240 nm and Zeta potential –57 mV), which remained unchanged over 5 weeks of stability study at 4 °C, and pH-dependent INH release behaviour alike PIL. Furthermore, CP was co-encapsulated with rifampicin (RIF) in liposomes using HM to investigate the possibility for future combination therapy. 1H-NMR spectroscopy, DSC, XRD and photophysical studies were performed for molecular assessment of the cargo in CP-RIF co-loaded liposomes (CPRL). The mean particle size, Zeta potential and î of CPRL were respectively 594 nm, –50 mV, 58 % for CP and 86 % for RIF. CPRL exhibited much higher release rates for both INH and RIF at pH 6.4, compared to those tested at pH 7.4. In addition, there was no cytotoxicity on HeLa cells, but attractive lung fibroblasts and epithelial cells uptake and viability. Hence, CPRL are promising for targeted ATBD delivery to alveolar macrophages following pulmonary administration. Overall, the developed pH-responsive liposomal system holds the promise for new openings towards wider developments of multifunctional liposomes for site-specific controlled pulmonary delivery of antimicrobials drugs.
- Full Text:
- Date Issued: 2019
- Authors: Nkanga, Christian Isalomboto
- Date: 2019
- Subjects: Tuberculosis -- Chemotherapy , Lipsomes , Drug carriers (Pharmacy) , Rifampin , Hydrogen-ion concentration , Hydrogen-ion concentration -- Physiological effect
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/125832 , vital:35822
- Description: Tuberculosis (TB) is an infectious disease that has been reported to be the ninth leading cause of death worldwide, even though mostly considered as a poverty related disease. Despite the existence of potent anti-tubercular drugs (ATBDs), such as rifampicin (RIF) and isoniazid (INH), TB remains the major killer among many microbial diseases over the last five years. Although several factors are to be blamed for this deadly status, the most crucial issues encompass both the self-defensiveness of the causative agent (Mycobacterium tuberculosis), including its intra-macrophage location that compromises ATBDs accessibility, and the widespread/off target distribution of ATBDs. The need for novel drug delivery strategies therefore arises to provide selective distribution of ATBDs at the infected site. Among the drug vehicles explored in this field, liposomes have been reported to be the most suitable drug carriers due to their rapid uptake by alveolar macrophages, where M. tuberculosis often resides. Since liposomes experience media of different pH throughout the cell uptake process (endocytosis/phagocytosis), the use of pH change as a stimulus for controlled release looks promising for enhancing intra-macrophage delivery and minimizing premature ‘off-target’ release of ATBDs. However, the costly status of liposome technology, due to the use of sophisticated procedures and expensive materials (especially for pH-dependent delivery, where special lipids are required), may preclude wider developments of liposomal products, especially for the developing world. This study aimed at investigating liposomal encapsulation of pH-sensitive and fluorescent hydrazone derivatives of INH using crude soybean lecithin, as a cost-effective option for site-specific delivery combined with potential bio-imaging features. Another objective was to explore encapsulation of INH hydrazone derivatives with and without RIF in liposomes using a simple and organic solvent-free preparation method. Initially, INH was coupled with 4-hydroxy-benzaldehyde to yield a conjugate (INH-HB) that was encapsulated in liposomes using film hydration method with acceptable encapsulation efficiency (î), about 89 %. The prepared INH-HB loaded liposomes (IHL) were characterized by means of dynamic light scattering (DLS), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The release of INH from IHL was evaluated over 12 hours in media of different pH using dialysis. As hypothesized, pH dependent release of INH from IHL was observed with 22, 69, 83 and 100 % release obtained in media of pH 7.4, 6.4, 5.4 and 4.4, respectively. From this experimental trial, further development was undertaken by conjugating INH to a hydrophobic fluorescent tag, zinc (II) phthalocyanine (PC), through hydrazone linkages. The obtained conjugate (PC-INH) was loaded into liposomes (PIL) that were characterized using various spectroscopic techniques, including UV-Vis absorption and energy dispersive X-ray spectroscopy, which suggested the presence of PC-INH within the lipid bilayers. The release study performed in different pH media revealed 22, 41, 97 and 100 % of INH, respectively released at pH 7.4, 6.4, 5.4 and 4.4. This confirmed the potential of pH-triggered drug release from liposomes loaded with hydrazone drug derivatives. In addition, successful encapsulation of PC-INH using crude soybean lecithin inspired a new opening towards development of multimodal liposomes that could achieve controlled drug release with added benefits of image-guided biological tracking. However, the hydrophobic nature of PC-INH requires an effective strategy that could improve its solubility and favour extensive development. In this context, the tetra-substituted structure of PC-INH brought up the hypothesis that cyclodextrin (CD) complexation would facilitate PC-INH encapsulation in liposomes using an organic solvent-free method, called here the “heating method” (HM). Inclusion complexes of PC-INH with various CDs were therefore investigated, with gamma-CD complex (CP) giving the best results. These complexes were prepared in both solution and solid-state and further comprehensively characterized using UV-Vis spectroscopy, magnetic circular dichroism, NMR spectroscopy, diffusion ordered spectroscopy, DSC, XRD and Fourier transform infrared spectroscopy. CP-loaded liposomes prepared using HM exhibited greater î than film hydration liposomes, about 70 % versus 56 %, respectively. The HM-liposomal system (CPL) exhibited potentially useful nano particulate characteristics (i.e. mean particle size 240 nm and Zeta potential –57 mV), which remained unchanged over 5 weeks of stability study at 4 °C, and pH-dependent INH release behaviour alike PIL. Furthermore, CP was co-encapsulated with rifampicin (RIF) in liposomes using HM to investigate the possibility for future combination therapy. 1H-NMR spectroscopy, DSC, XRD and photophysical studies were performed for molecular assessment of the cargo in CP-RIF co-loaded liposomes (CPRL). The mean particle size, Zeta potential and î of CPRL were respectively 594 nm, –50 mV, 58 % for CP and 86 % for RIF. CPRL exhibited much higher release rates for both INH and RIF at pH 6.4, compared to those tested at pH 7.4. In addition, there was no cytotoxicity on HeLa cells, but attractive lung fibroblasts and epithelial cells uptake and viability. Hence, CPRL are promising for targeted ATBD delivery to alveolar macrophages following pulmonary administration. Overall, the developed pH-responsive liposomal system holds the promise for new openings towards wider developments of multifunctional liposomes for site-specific controlled pulmonary delivery of antimicrobials drugs.
- Full Text:
- Date Issued: 2019
Photophysical properties and photodynamic therapy activities of symmetrical and asymmetrical porphyrins embedded into Pluronic polymer micelles and nonlinear optical properties of an asymmetrical phthalocyanine
- Authors: Managa, Muthumuni Elizabeth
- Date: 2019
- Subjects: Porphyrins , Phthalocyanines
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/67625 , vital:29122
- Description: This work reports on the synthesis of symmetrical and asymmetrical novel porphyrins that have been incorporated into Pluronic polymers, as well as the synthesis of asymmetrical phthalocyanine. The new compounds were characterized by elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR), mass spectrometry and UV–Visible spectroscopy. The porphyrins that are synthesised were not water soluble but upon incorporating into Pluronic polymer micelles, they became water soluble. The polymer was also modified and linked to folic acid, to enhance selectivity for photodynamic therapy application, where MCF7 breast cancer cells were used. The singlet oxygen quantum yields were lower for the metal free porphyrins as compared to metalled ones due to the heavy atom effect of ClGa, Zn and Cl2Si in the latter which encourages intersystem crossing to the triplet state. Singlet oxygen quantum yields for water soluble derivatives increased upon being encapsulated into the micelles for all. The Stern-Volmer constant (Ksv), binding constant (Kb) and number of binding sites (n) were investigated in order to understand the interaction between the polymer micelles and the porphyrins, and it was showed that the central metals play a role in the manner which the porphyrin interacts with the micelles. The dark toxicity and photodynamic activity of the novel porphyrins upon encapsulating to Pluronic polymer micelles is also reported. There was minimal dark toxicity for all complexes with > 90% cell survival. The photodynamic activity of water insoluble porphyrins improved when encapsulated into the micelles. Novel asymmetrical phthalocyanines were also synthesised for nonlinear optics (NLO) studies in solution and thin films.
- Full Text:
- Date Issued: 2019
- Authors: Managa, Muthumuni Elizabeth
- Date: 2019
- Subjects: Porphyrins , Phthalocyanines
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/67625 , vital:29122
- Description: This work reports on the synthesis of symmetrical and asymmetrical novel porphyrins that have been incorporated into Pluronic polymers, as well as the synthesis of asymmetrical phthalocyanine. The new compounds were characterized by elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR), mass spectrometry and UV–Visible spectroscopy. The porphyrins that are synthesised were not water soluble but upon incorporating into Pluronic polymer micelles, they became water soluble. The polymer was also modified and linked to folic acid, to enhance selectivity for photodynamic therapy application, where MCF7 breast cancer cells were used. The singlet oxygen quantum yields were lower for the metal free porphyrins as compared to metalled ones due to the heavy atom effect of ClGa, Zn and Cl2Si in the latter which encourages intersystem crossing to the triplet state. Singlet oxygen quantum yields for water soluble derivatives increased upon being encapsulated into the micelles for all. The Stern-Volmer constant (Ksv), binding constant (Kb) and number of binding sites (n) were investigated in order to understand the interaction between the polymer micelles and the porphyrins, and it was showed that the central metals play a role in the manner which the porphyrin interacts with the micelles. The dark toxicity and photodynamic activity of the novel porphyrins upon encapsulating to Pluronic polymer micelles is also reported. There was minimal dark toxicity for all complexes with > 90% cell survival. The photodynamic activity of water insoluble porphyrins improved when encapsulated into the micelles. Novel asymmetrical phthalocyanines were also synthesised for nonlinear optics (NLO) studies in solution and thin films.
- Full Text:
- Date Issued: 2019
Physicochemical properties and photodynamic therapy activities of indium and zinc phthalocyanine-nanoparticle conjugates
- Authors: Dube, Edith
- Date: 2019
- Subjects: Indium , Zinc , Phthalocyanines , Breast -- Cancer -- Photochemotherapy , Nanoparticles
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76506 , vital:30589
- Description: The syntheses and characterization of symmetric and asymmetric Pcs functionalized at the peripheral position are reported. The Pcs contain either zinc or indium as central metals and have carboxyphenoxy, phenoxy propanoic acid, benzothiazole phenoxy, thiophine ethoxy or di-O-isopropylidene-α-D-glucopyranose as ring substituents. The Pcs were linked to NPs via an amide bond or through self-assembly. The photophysics and photochemistry of the Pcs were assessed when alone and with conjugates. All the studied Pcs showed good photophysicochemical behaviour with relatively high triplet and singlet oxygen quantum yields corresponding to their low fluorescence quantum yield. The Pcs with indium in their central cavity exhibited higher triplet and singlet oxygen quantum yields in comparison to their zinc counterparts due to the heavy–atom effect obtained from the former. Asymmetrical Pcs displayed higher triplet and singlet oxygen quantum yields than their symmetrical counterparts. The triplet quantum yield, generally increased on linkage to nanoparticles (NPs) due to the heavy–atom effect of gold and silver in NPs. The conjugates to gold nanospheres yielded higher triplet and singlet quantum yields than their gold nanotriangles counterparts due to the higher loading by the former probably encouraged by their relatively small particle size. The in vitro dark cytotoxicity and photodynamic therapy of selected Pc complexes and conjugates against MCF-7 cells was tested. All studied Pc complexes and conjugates showed minimum dark toxicity making them applicable for PDT. All complexes displayed poor phototoxicity with >50Îll viability at concentrations≤ 160μg/mL, however the conjugates showed<50% cell viabilityatconcentrations≤ 160μg/mLprobably due to the enhanced singlet oxygen quantum yield. The findings from this work show the importance of linking photosensitises such as phthalocyanines to metal nanoparticles for the enhancement ofsinglet oxygen quantum yield and ultimately the photodynamic effect.
- Full Text:
- Date Issued: 2019
- Authors: Dube, Edith
- Date: 2019
- Subjects: Indium , Zinc , Phthalocyanines , Breast -- Cancer -- Photochemotherapy , Nanoparticles
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76506 , vital:30589
- Description: The syntheses and characterization of symmetric and asymmetric Pcs functionalized at the peripheral position are reported. The Pcs contain either zinc or indium as central metals and have carboxyphenoxy, phenoxy propanoic acid, benzothiazole phenoxy, thiophine ethoxy or di-O-isopropylidene-α-D-glucopyranose as ring substituents. The Pcs were linked to NPs via an amide bond or through self-assembly. The photophysics and photochemistry of the Pcs were assessed when alone and with conjugates. All the studied Pcs showed good photophysicochemical behaviour with relatively high triplet and singlet oxygen quantum yields corresponding to their low fluorescence quantum yield. The Pcs with indium in their central cavity exhibited higher triplet and singlet oxygen quantum yields in comparison to their zinc counterparts due to the heavy–atom effect obtained from the former. Asymmetrical Pcs displayed higher triplet and singlet oxygen quantum yields than their symmetrical counterparts. The triplet quantum yield, generally increased on linkage to nanoparticles (NPs) due to the heavy–atom effect of gold and silver in NPs. The conjugates to gold nanospheres yielded higher triplet and singlet quantum yields than their gold nanotriangles counterparts due to the higher loading by the former probably encouraged by their relatively small particle size. The in vitro dark cytotoxicity and photodynamic therapy of selected Pc complexes and conjugates against MCF-7 cells was tested. All studied Pc complexes and conjugates showed minimum dark toxicity making them applicable for PDT. All complexes displayed poor phototoxicity with >50Îll viability at concentrations≤ 160μg/mL, however the conjugates showed<50% cell viabilityatconcentrations≤ 160μg/mLprobably due to the enhanced singlet oxygen quantum yield. The findings from this work show the importance of linking photosensitises such as phthalocyanines to metal nanoparticles for the enhancement ofsinglet oxygen quantum yield and ultimately the photodynamic effect.
- Full Text:
- Date Issued: 2019
Physiological and mechanistic characteristics of all-out running using the critical speed concept
- Authors: Kramer, Mark
- Date: 2019
- Subjects: Aerobic exercises , Physical fitness Running Exercise
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/40511 , vital:36178
- Description: The studies described in this thesis, as far as could be ascertained, were the first to investigate the physiological and mechanistic characteristics of all-out running using the critical speed concept specifically applied to field-sport athletes. In the first study the oxygen uptake (𝑉̇𝑂2) kinetics of linear and shuttle all-out running were investigated. The 𝑉̇𝑂2 kinetic parameters were also related to parameters derived from a graded exercise test. No differences were observed in all 𝑉̇ 𝑂2 kinetic parameters between all-out linear and shuttle running, even though differences in all-out testing parameters were evident. The study was novel in that it was, as far as could be ascertained, the first to implement and investigate differences in 𝑉̇𝑂2 kinetics applied to all-out running. The second study investigated whether the parameters derived from all-out linear and shuttle running were representative of aerobic fitness, and the extent to which the all-out test (AOT) related to already established evaluations of aerobic fitness (e.g., graded exercise test [GXT] and the Yo-Yo intermittent recovery test [YYIR1]). It was also investigated whether the parameters from the AOTs could be used to predict the time to completion (tLIM) of shuttle-based performances. The outcomes of this study showed that both the linear and 50-m AOTs were indeed valid for the aerobic assessment of fitness by showing high correlations with maximal pulmonary oxygen uptake (𝑉̇𝑂2𝑚𝑎𝑥). Both the linear and 50-m AOT could therefore be used as surrogates for the evaluation of aerobic fitness. Interestingly, in terms of the tLIM prediction, the 25-m AOT showed the greatest utility. This study was novel on several fronts in that it was the first to: (1) investigate the physiological link between linear and shuttle AOTs and the GXT, (2) investigate the difference between AOTs and the YYIR1, and (3) investigate the application of the AOT methodology to field-based athletes such as rugby players. The third study investigated the energetic cost (EC) of locomotion as well as the metabolic power (𝑃̇) required to run at given speeds. The energetic approach provides a more robust evaluation of the differences between linear and shuttle running due to the all-out nature of the tests. Conventional methods of energy assessment often fall short due to the preclusion of a physiological steady-state, hence requiring more robust mathematical models to evaluate all-out running performance. The results of this study showed that differences between linear and shuttle AOTs are more likely neuromuscular as opposed to physiological. Peak EC and 𝑃̇ were significantly greater for shuttle running compared to linear running, showing clear non-linear increases with each successive increase in running speed. However, the mean EC and 𝑃̇ were not different, showing that all-out shuttle running ‘balances’ the lower running speeds (implying a lower physiological load compared to linear running) with the higher metabolic load imposed by the intense directional changes. This study was novel as it was, as far as could be ascertained, the first to apply the energetic approach to all-out running as well as investigate the differences in energetics between linear and shuttle AOTs. The fourth study provided a means by which the speed-time characteristics of all-out running could be objectively quantified. A novel bi-exponential model was applied to both the linear and shuttle speed-time curves and allowed various mechanistic aspects of the speed-time curve to be characterized. Conventional assessment of the AOT allows for the derivation of only two key parameters, namely critical speed (CS) and the finite distance achievable at speeds exceeding CS (D’). The application of the bi-exponential model expands the number of useful parameters that can be derived from an AOT to seven. The additional useful parameters include: maximum speed [𝑆𝑚𝑎𝑥], time to maximum speed [𝑡𝑐], amplitude of the difference between 𝑆𝑚𝑎𝑥 and CS [𝐴𝑑], curvature constant of the exponential decay [𝜏𝑑] and the asymptote of the exponential decay function [𝑆0], fatigue index showing the percent decline between 𝑆𝑚𝑎𝑥 and CS [FI%], and the finite capacity for running at speeds exceeding CS [D’; representing the area under the curve that is above CS]. The CS and D’ parameters derived from the bi-exponential model were not different to the CS and D’ parameters derived using the conventional method of analysis, thereby showing that the bi-exponential model is a valid means of assessing the curvature characteristics of the AOT, as well as providing additional information that cannot be gleaned from the traditional approach.
- Full Text:
- Date Issued: 2019
- Authors: Kramer, Mark
- Date: 2019
- Subjects: Aerobic exercises , Physical fitness Running Exercise
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/40511 , vital:36178
- Description: The studies described in this thesis, as far as could be ascertained, were the first to investigate the physiological and mechanistic characteristics of all-out running using the critical speed concept specifically applied to field-sport athletes. In the first study the oxygen uptake (𝑉̇𝑂2) kinetics of linear and shuttle all-out running were investigated. The 𝑉̇𝑂2 kinetic parameters were also related to parameters derived from a graded exercise test. No differences were observed in all 𝑉̇ 𝑂2 kinetic parameters between all-out linear and shuttle running, even though differences in all-out testing parameters were evident. The study was novel in that it was, as far as could be ascertained, the first to implement and investigate differences in 𝑉̇𝑂2 kinetics applied to all-out running. The second study investigated whether the parameters derived from all-out linear and shuttle running were representative of aerobic fitness, and the extent to which the all-out test (AOT) related to already established evaluations of aerobic fitness (e.g., graded exercise test [GXT] and the Yo-Yo intermittent recovery test [YYIR1]). It was also investigated whether the parameters from the AOTs could be used to predict the time to completion (tLIM) of shuttle-based performances. The outcomes of this study showed that both the linear and 50-m AOTs were indeed valid for the aerobic assessment of fitness by showing high correlations with maximal pulmonary oxygen uptake (𝑉̇𝑂2𝑚𝑎𝑥). Both the linear and 50-m AOT could therefore be used as surrogates for the evaluation of aerobic fitness. Interestingly, in terms of the tLIM prediction, the 25-m AOT showed the greatest utility. This study was novel on several fronts in that it was the first to: (1) investigate the physiological link between linear and shuttle AOTs and the GXT, (2) investigate the difference between AOTs and the YYIR1, and (3) investigate the application of the AOT methodology to field-based athletes such as rugby players. The third study investigated the energetic cost (EC) of locomotion as well as the metabolic power (𝑃̇) required to run at given speeds. The energetic approach provides a more robust evaluation of the differences between linear and shuttle running due to the all-out nature of the tests. Conventional methods of energy assessment often fall short due to the preclusion of a physiological steady-state, hence requiring more robust mathematical models to evaluate all-out running performance. The results of this study showed that differences between linear and shuttle AOTs are more likely neuromuscular as opposed to physiological. Peak EC and 𝑃̇ were significantly greater for shuttle running compared to linear running, showing clear non-linear increases with each successive increase in running speed. However, the mean EC and 𝑃̇ were not different, showing that all-out shuttle running ‘balances’ the lower running speeds (implying a lower physiological load compared to linear running) with the higher metabolic load imposed by the intense directional changes. This study was novel as it was, as far as could be ascertained, the first to apply the energetic approach to all-out running as well as investigate the differences in energetics between linear and shuttle AOTs. The fourth study provided a means by which the speed-time characteristics of all-out running could be objectively quantified. A novel bi-exponential model was applied to both the linear and shuttle speed-time curves and allowed various mechanistic aspects of the speed-time curve to be characterized. Conventional assessment of the AOT allows for the derivation of only two key parameters, namely critical speed (CS) and the finite distance achievable at speeds exceeding CS (D’). The application of the bi-exponential model expands the number of useful parameters that can be derived from an AOT to seven. The additional useful parameters include: maximum speed [𝑆𝑚𝑎𝑥], time to maximum speed [𝑡𝑐], amplitude of the difference between 𝑆𝑚𝑎𝑥 and CS [𝐴𝑑], curvature constant of the exponential decay [𝜏𝑑] and the asymptote of the exponential decay function [𝑆0], fatigue index showing the percent decline between 𝑆𝑚𝑎𝑥 and CS [FI%], and the finite capacity for running at speeds exceeding CS [D’; representing the area under the curve that is above CS]. The CS and D’ parameters derived from the bi-exponential model were not different to the CS and D’ parameters derived using the conventional method of analysis, thereby showing that the bi-exponential model is a valid means of assessing the curvature characteristics of the AOT, as well as providing additional information that cannot be gleaned from the traditional approach.
- Full Text:
- Date Issued: 2019
Plants, people, and place: complex, mutualistic, and co-evolving global patterns through time
- Authors: Van Wijk, Yvette Ethné
- Date: 2019
- Subjects: Ethnobotany -- South Africa -- Western Cape , Khoisan (African people) -- Ethnobotany , Human-plant relationships -- South Africa -- Western Cape , Plants -- Classification -- South Africa -- Western Cape , Plant remains (Archaeology) -- South Africa -- Western Cape , Ethnoscience -- South Africa -- Western Cape , Regression analysis
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76575 , vital:30609
- Description: My thesis studies and analyses the suite of distinctive plant taxa which persist in small patches of vegetation growing in close association with archaeological habitation sites in the southern Cape, South Africa. The unexpected correlation and overlap between botanical taxa collected at 75 site complexes, and ethnobotanical data collected in collaboration with modern Khoi-San communities in the same area, is explored and interrogated. Although sparse, reports of the same suite of taxa recovered from archaeological excavations in the Cape provinces provides depth of time to the study, linking the past to the present. The three-way correlation of a suite of plants closely associated with humans and habitation sites through time, allows for triangulation of the data in order to validate and cross verify the results using more than one frame of reference. Both the plants and the knowledge about their uses have persisted in spite of historical attrition, and alienation of land and language, suffered by the Khoi-San over the past 300 years. Drawing on a large body of primary and secondary data, and using an interdisciplinary, abductive and pragmatic mixed methods approach, a pattern can be traced throughout Africa and globally. Regression analysis strongly indicates that the most ubiquitous taxa were selected for a purpose and are not randomly present in association with humans. Botanical, anthropological, and archaeological studies seldom focus on the inter-connectedness of people and plants at the sites they inhabited. Very little research into modern vegetation in close association with the sites has been undertaken, and vegetation mapping has not captured the occurrence of these site-specific small vegetation patches recorded during my surveys. The topographically, geologically, and vegetatively complex and varied southern Cape, and greater Cape area, is extremely rich in archaeological sites and history. This study suggests that the value of site-specific plant taxa to humans throughout the aeons of pre-agricultural history, persists into the present. Due to tolerance of a broad range of climatic and environmental variables, there is value in the study of these ancient and neglected useful plants in the face of climate change. That this vegetation is so closely associated with archaeological sites of cultural and historic importance confers an urgency to recognising the existence and significance of the distinctive and possibly anthropogenic vegetation surrounding the sites.
- Full Text:
- Date Issued: 2019
- Authors: Van Wijk, Yvette Ethné
- Date: 2019
- Subjects: Ethnobotany -- South Africa -- Western Cape , Khoisan (African people) -- Ethnobotany , Human-plant relationships -- South Africa -- Western Cape , Plants -- Classification -- South Africa -- Western Cape , Plant remains (Archaeology) -- South Africa -- Western Cape , Ethnoscience -- South Africa -- Western Cape , Regression analysis
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76575 , vital:30609
- Description: My thesis studies and analyses the suite of distinctive plant taxa which persist in small patches of vegetation growing in close association with archaeological habitation sites in the southern Cape, South Africa. The unexpected correlation and overlap between botanical taxa collected at 75 site complexes, and ethnobotanical data collected in collaboration with modern Khoi-San communities in the same area, is explored and interrogated. Although sparse, reports of the same suite of taxa recovered from archaeological excavations in the Cape provinces provides depth of time to the study, linking the past to the present. The three-way correlation of a suite of plants closely associated with humans and habitation sites through time, allows for triangulation of the data in order to validate and cross verify the results using more than one frame of reference. Both the plants and the knowledge about their uses have persisted in spite of historical attrition, and alienation of land and language, suffered by the Khoi-San over the past 300 years. Drawing on a large body of primary and secondary data, and using an interdisciplinary, abductive and pragmatic mixed methods approach, a pattern can be traced throughout Africa and globally. Regression analysis strongly indicates that the most ubiquitous taxa were selected for a purpose and are not randomly present in association with humans. Botanical, anthropological, and archaeological studies seldom focus on the inter-connectedness of people and plants at the sites they inhabited. Very little research into modern vegetation in close association with the sites has been undertaken, and vegetation mapping has not captured the occurrence of these site-specific small vegetation patches recorded during my surveys. The topographically, geologically, and vegetatively complex and varied southern Cape, and greater Cape area, is extremely rich in archaeological sites and history. This study suggests that the value of site-specific plant taxa to humans throughout the aeons of pre-agricultural history, persists into the present. Due to tolerance of a broad range of climatic and environmental variables, there is value in the study of these ancient and neglected useful plants in the face of climate change. That this vegetation is so closely associated with archaeological sites of cultural and historic importance confers an urgency to recognising the existence and significance of the distinctive and possibly anthropogenic vegetation surrounding the sites.
- Full Text:
- Date Issued: 2019
Pragmatics teaching: on the development of learners’ linguistic competence among selected East London District schools
- Authors: Myoli, Ndileka
- Date: 2019
- Subjects: Pragmatics -- Study and teaching Language and languages -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/11232 , vital:37607
- Description: South Africa was listed amongst the countries with a percentage of students with achievement too low for estimation by “Progress International Results in Reading” in 2011. Meanwhile, there was also an indication that, high school learners in the Eastern Cape Province are highly challenged, as far as their ability to produce speech, as well as the ability to interpret meaning beyond what is literally suggested. Since such difficulties usually pose problems of content understanding, concerned researchers in the field of language took it upon themselves to investigate the underlying cause of the problem, in order to prevent more problems of pragmatics incompetence, such as, problems with social interaction that could retard one’s ability to function independently as an adult. While many studies have been conducted in the area of Pragmatics language competence, this study found it necessary to contribute around this debate. Since the study was two-fold, isiXhosa Home language learners of Grades 10 to 12 were investigated with an objective to determine the extent of pragmatic incompetence and the Teachers were investigated to determine the effectiveness of their teaching of pragmatics language. A number of 108 high school isiXhosa learners, of ages of between 16 and 18 years, from East London Directorate, 36 per Grade, from the three selected schools high schools, were sampled, 36 consisting of 18 males and 18 females per grade from each selected high school. 9 isiXhosa Home Language teachers of between the ages of 45 to 54 years were sampled from the selected schools. This study used an assessment test for the learners and the questionnaire for the teachers, as a means of data collection techniques. The study applied a high consideration of validity as well as of ethical matters in order to ensure the reliability of results. The study found that, isiXhosa Home language learners’ levels of pragmatic competence are high and with the appropriate use of good methods of pragmatics language teaching, learners’ pragmatics competence can develop.This study will be able to encourage syllabus designers to collaborate with subject teachers, beginning right at the inception of the syllabus planning. IsiXhosa language teachers can develop teaching material appropriate for their primary goal, which is the development of pragmatic competence. Further research is recommended to investigate more around this area of study to a point where isiXhosa Home language can be counted amongst the great and valued languages of South Africa.
- Full Text:
- Date Issued: 2019
- Authors: Myoli, Ndileka
- Date: 2019
- Subjects: Pragmatics -- Study and teaching Language and languages -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/11232 , vital:37607
- Description: South Africa was listed amongst the countries with a percentage of students with achievement too low for estimation by “Progress International Results in Reading” in 2011. Meanwhile, there was also an indication that, high school learners in the Eastern Cape Province are highly challenged, as far as their ability to produce speech, as well as the ability to interpret meaning beyond what is literally suggested. Since such difficulties usually pose problems of content understanding, concerned researchers in the field of language took it upon themselves to investigate the underlying cause of the problem, in order to prevent more problems of pragmatics incompetence, such as, problems with social interaction that could retard one’s ability to function independently as an adult. While many studies have been conducted in the area of Pragmatics language competence, this study found it necessary to contribute around this debate. Since the study was two-fold, isiXhosa Home language learners of Grades 10 to 12 were investigated with an objective to determine the extent of pragmatic incompetence and the Teachers were investigated to determine the effectiveness of their teaching of pragmatics language. A number of 108 high school isiXhosa learners, of ages of between 16 and 18 years, from East London Directorate, 36 per Grade, from the three selected schools high schools, were sampled, 36 consisting of 18 males and 18 females per grade from each selected high school. 9 isiXhosa Home Language teachers of between the ages of 45 to 54 years were sampled from the selected schools. This study used an assessment test for the learners and the questionnaire for the teachers, as a means of data collection techniques. The study applied a high consideration of validity as well as of ethical matters in order to ensure the reliability of results. The study found that, isiXhosa Home language learners’ levels of pragmatic competence are high and with the appropriate use of good methods of pragmatics language teaching, learners’ pragmatics competence can develop.This study will be able to encourage syllabus designers to collaborate with subject teachers, beginning right at the inception of the syllabus planning. IsiXhosa language teachers can develop teaching material appropriate for their primary goal, which is the development of pragmatic competence. Further research is recommended to investigate more around this area of study to a point where isiXhosa Home language can be counted amongst the great and valued languages of South Africa.
- Full Text:
- Date Issued: 2019
Pyramidal deliberative democracy
- Authors: Danielsen, James
- Date: 2019
- Subjects: Democracy , Information technology -- Political aspects , Internet in public administration , Political participation -- Computer network resources , World politics
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/74502 , vital:30309
- Description: This dissertation has two main objectives. First, to outline an ICT-facilitated model of democracy called ‘pyramidal democracy’ that reconciles deliberative democracy with mass engagement. Second, to suggest how this model of democracy might engender the democratisation of the global economy and thus the provision of a basic level of economic security for all global citizens. At the core of the model is the pyramidal deliberative network, a means of organising citizens into small online deliberative groups and linking these groups together by means of an iterative process of delegate-selection and group-formation. The pyramidal network enables citizens to aggregate their preferences in a deliberative manner, and then project social power by authorizing the delegates at the top-tier of the pyramidal network to communicate their social demands to elected officials or to other points of authority. The envisioned outcome is the democratisation of the public sphere by means of the proliferation of deliberative networks in the government, market, and civil society spheres. Transnational pyramidal networks may make it feasible to instantiate a new citizen-based schema of global governance and, thereby, facilitate the reform of the United Nations and enable a transition towards global peace, sustainability, and distributive justice. Distributive justice might be achieved by means of implementing the six components of a democratised economy: participatory budgeting, fee-and-dividend taxes, a basic income, monetary reform, workplace democracy, and the sharing economy. Taken together, these components might enable the universal provision of a social minimum – a universal basic income sufficient for basic security and real freedom. Taken to its logical conclusion, a democratised economy may also enable a transition towards a post-scarcity economic order characterised by a maximal stock of humanmade and natural capital that would not exceed the sustainable carrying capacity of the earth.
- Full Text:
- Date Issued: 2019
- Authors: Danielsen, James
- Date: 2019
- Subjects: Democracy , Information technology -- Political aspects , Internet in public administration , Political participation -- Computer network resources , World politics
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/74502 , vital:30309
- Description: This dissertation has two main objectives. First, to outline an ICT-facilitated model of democracy called ‘pyramidal democracy’ that reconciles deliberative democracy with mass engagement. Second, to suggest how this model of democracy might engender the democratisation of the global economy and thus the provision of a basic level of economic security for all global citizens. At the core of the model is the pyramidal deliberative network, a means of organising citizens into small online deliberative groups and linking these groups together by means of an iterative process of delegate-selection and group-formation. The pyramidal network enables citizens to aggregate their preferences in a deliberative manner, and then project social power by authorizing the delegates at the top-tier of the pyramidal network to communicate their social demands to elected officials or to other points of authority. The envisioned outcome is the democratisation of the public sphere by means of the proliferation of deliberative networks in the government, market, and civil society spheres. Transnational pyramidal networks may make it feasible to instantiate a new citizen-based schema of global governance and, thereby, facilitate the reform of the United Nations and enable a transition towards global peace, sustainability, and distributive justice. Distributive justice might be achieved by means of implementing the six components of a democratised economy: participatory budgeting, fee-and-dividend taxes, a basic income, monetary reform, workplace democracy, and the sharing economy. Taken together, these components might enable the universal provision of a social minimum – a universal basic income sufficient for basic security and real freedom. Taken to its logical conclusion, a democratised economy may also enable a transition towards a post-scarcity economic order characterised by a maximal stock of humanmade and natural capital that would not exceed the sustainable carrying capacity of the earth.
- Full Text:
- Date Issued: 2019
Reading to learn for secondary schooling: an interventionist action research study within a South African under-privileged setting
- Authors: Mataka, Tawanda Wallace
- Date: 2019
- Subjects: Rose, David, 1955-. Reading to learn , Reading (Secondary) , English language -- Study and teaching (Secondary) -- Foreign speakers -- South Africa , English language -- Study and teaching (Secondary) -- Foreign speakers -- South Africa -- Case studies , Literacy -- South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92191 , vital:30706
- Description: The study examined the contribution that Rose’s (2005) Reading to Learn (RtL) methodology made in development of advanced literacy abilities recommended in the schooling system. RtL was influenced by Bernstein’s theory of pedagogic discourse, Bruner, Vygotsky’s social learning theory and Halliday’s systemic functional linguistics theory. The study used the same cohort of learners during Grades 11 and 12 in a black township secondary school in Grahamstown, Eastern Cape, South Africa. RtL was birthed in Australia with the intention of accelerating literacy development of learners in disadvantaged communities. Based on its success in Australia, I implemented the methodology against a backdrop of continuously declining literacy standards in South African primary and secondary schools. Researchers on literacy acknowledge that socioeconomic and geosocial circumstances cannot be divorced from poor literacy performances in South African schools. Although these two factors play a role in regressing literacy, pedagogical approaches play a role. RtL was employed as an intervention strategy with learners whose literacy abilities were found lacking in comparison to curriculum demands. Despite the focus being on learners whose performance was below expected academic levels, the able learners were motivated to further their advanced abilities. The learners whose performance was previously compromised performed to par with their able counterparts. RtL provided all learners an opportunity to apply, with less difficulty, the language approved by the schooling system. The two research questions sought to illuminate the role RtL played in developing learners’ ability to read, so that they could converse with text and put into writing practice what they had read. In this regard, creative and transactional assignments were written, and performance assessed to evaluate the RtL intervention. Secondly, the research allowed me to get an insight through interviews with learners as to how they were positively or negatively influenced through RtL in learning English as a First Additional Language. The study was a longitudinal action research study which had a life span of 22 months. It was dominantly qualitative with a thin quantitative strand. Data to evaluate effectiveness was generated from learners’ written work and interviews. The learners’ work was analysed using an RtL assessment tool adopted from Rose (2018), for the purposes of uniformity and reliability. Findings from interviews highlighted various views regarding the positive impact of RtL. What emerged from the findings is a reflection of the positive impact RtL had on literacy development. Significantly, learners’ work improved across the board, true to Rose’s assertion that learners exposed to teaching using RtL principles experience accelerated literacy development. Based on these findings, RtL implemented in a township setting in South Africa yields results similar to those in Australia and other countries.
- Full Text:
- Date Issued: 2019
- Authors: Mataka, Tawanda Wallace
- Date: 2019
- Subjects: Rose, David, 1955-. Reading to learn , Reading (Secondary) , English language -- Study and teaching (Secondary) -- Foreign speakers -- South Africa , English language -- Study and teaching (Secondary) -- Foreign speakers -- South Africa -- Case studies , Literacy -- South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92191 , vital:30706
- Description: The study examined the contribution that Rose’s (2005) Reading to Learn (RtL) methodology made in development of advanced literacy abilities recommended in the schooling system. RtL was influenced by Bernstein’s theory of pedagogic discourse, Bruner, Vygotsky’s social learning theory and Halliday’s systemic functional linguistics theory. The study used the same cohort of learners during Grades 11 and 12 in a black township secondary school in Grahamstown, Eastern Cape, South Africa. RtL was birthed in Australia with the intention of accelerating literacy development of learners in disadvantaged communities. Based on its success in Australia, I implemented the methodology against a backdrop of continuously declining literacy standards in South African primary and secondary schools. Researchers on literacy acknowledge that socioeconomic and geosocial circumstances cannot be divorced from poor literacy performances in South African schools. Although these two factors play a role in regressing literacy, pedagogical approaches play a role. RtL was employed as an intervention strategy with learners whose literacy abilities were found lacking in comparison to curriculum demands. Despite the focus being on learners whose performance was below expected academic levels, the able learners were motivated to further their advanced abilities. The learners whose performance was previously compromised performed to par with their able counterparts. RtL provided all learners an opportunity to apply, with less difficulty, the language approved by the schooling system. The two research questions sought to illuminate the role RtL played in developing learners’ ability to read, so that they could converse with text and put into writing practice what they had read. In this regard, creative and transactional assignments were written, and performance assessed to evaluate the RtL intervention. Secondly, the research allowed me to get an insight through interviews with learners as to how they were positively or negatively influenced through RtL in learning English as a First Additional Language. The study was a longitudinal action research study which had a life span of 22 months. It was dominantly qualitative with a thin quantitative strand. Data to evaluate effectiveness was generated from learners’ written work and interviews. The learners’ work was analysed using an RtL assessment tool adopted from Rose (2018), for the purposes of uniformity and reliability. Findings from interviews highlighted various views regarding the positive impact of RtL. What emerged from the findings is a reflection of the positive impact RtL had on literacy development. Significantly, learners’ work improved across the board, true to Rose’s assertion that learners exposed to teaching using RtL principles experience accelerated literacy development. Based on these findings, RtL implemented in a township setting in South Africa yields results similar to those in Australia and other countries.
- Full Text:
- Date Issued: 2019