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
An exploration of an environmental resource management course for sustainable development practitioners in Kenya : a case study
- Authors: Oteki, Jane Bosibori
- Date: 2014
- Subjects: Environmental management -- Kenya Sustainable development -- Kenya Environmental management -- Study and teaching -- Kenya Sustainable development -- Study and teaching -- Kenya Environmental education -- Study and teaching -- Kenya Environmental sciences -- Study and teaching -- Kenya Technical University of Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1964 , http://hdl.handle.net/10962/d1011611
- Description: Environmental challenges facing the world currently call for efforts that can avert eminent disasters related to these challenges. In an effort to engage in conservation, the Environmental Resource Management course at Technical University offers an opportunity to train for sustainable development in the country. However, the development and implementation of courses aimed at developing careers in sustainability in institutions of higher learning are coming under scrutiny as questions are being asked about their contributions to sustainable development. This research explored the Environmental Resource Management course to understand how it was developed and implemented to address a practitioner in the environmental resources conservation sector. The study surfaced the contradictions in the course which can be used as a lens to re-orient the course to enable a practitioner in education for sustainable development to emerge. In Kenya, vocational courses in environmental education are a career choice for secondary school leavers and those engaged in the environmental conservation sector. This study carried out at Technical University of Kenya (TU-K) between January 2009 and April 2012 aimed at exploring how a diploma course: Environmental Resource Management (ERM) enabled the learners to become practitioners in environmental resource management. It surfaced contradictions and suggested transformative approaches to re-orient the course for sustainable development. This was necessitated by the paradigm shift in environmental education from environmental conservation education that emphasised ecological studies to Education for Sustainable Development that is broader and more holistic, encompassing social, economic and environmental aspects. The course has to be re-orientated to enable a practitioner in Education for Sustainable Development (ESD) to emerge considering the United Nations Decade of Education for Sustainable Development (UNDESD, 2005-2014). The course aims at training personnel for deployment in environmental conservation and management organisations to work as resource officers/supervisors in national parks, forestry management, water management, energy development projects officers, etc. Data was gathered through document analysis, questionnaires, interviews, observation and focus group discussions. Cultural Historical Activity Theory (CHAT) was engaged in surfacing contradictions in the Environmental Resource Management learning system in terms of its development and implementation. While Communities of Practice (COP) principles were used as the ontological underpinning for the ERM course. The results indicate that the ERM course was revised between 1998 and 2002 by experts from Saskatchewan Institute of Science and Technology (SIAST) in collaboration with TU-K staff under the programme, enhancing environmental management in Kenya. The research also established that the ERM course review process was informed by sustainable development principles, as outlined in Agenda 21. Further it was realised that the Develop a Curriculum (DACUM) process was engaged to develop the learning units. This course development envisaged Competency Based Education (CBE) as the main mode of the ERM delivery. CBE is student centred and allows for multi-entry and exit. The study however realised that at implementation this approach was partially incorporated, as the country’s education system is examination oriented and time bound. The study findings indicate that most of the units taught were on ecosystem management with the social and economic aspects having less space and time, therefore the three pillars of Education for Sustainable Development were not adequately addressed in the course to enable a practitioner in the concept to emerge. Also teaching and learning in the course was found to be more theoretical than practical with little hands-on activities because the main focus of the course was to enable the learners to acquire a certificate through examination rather than gain the appropriate competencies. Although the course was found to be enhancing ESD in relation to global and local sustainability issues, there were contradictions or challenges in the system that affected full realisation of the skills, knowledge, values and attitudes. For example the exclusion of the recipient staff in the planning of the course, lack of training of the lecturers on how to train on CBE, insufficient practical field excursions devoid of community engagement, lack of funds, lack of equipment and poor coordination. This study recommends a re-orientation of the course to a more practical approach to teaching such as: • Engagement of students with the community to solve real-life environmental problems; • Mainstreaming ESD in all courses in the institutions of higher learning so that environmental concerns are addressed by everyone; • Reviewing the educational policy to encourage solving of real-life environmental problems rather than passing theoretical examinations; • Enhancing competency based learning to enable students to become competent in their areas of specialisation; • Encouraging networking and direct involvement of the students in the community instead of spending more time in class; and • Establishing a Community of Practice among the students in Higher Education Institutions to enhance conservation practices. The study contributes in-depth insight into exploring courses in Technical Vocational Education and Training institutions using Communities of Practice as a lens within the Kenyan context. It gives some empirical and explanatory insight into how learning can emerge and be expanded in Education for Sustainable Development through relevant courses such as tje Environmental Resource Management course. It also provides learning tools to work with contradictions that arise from socio-cultural and historical dimensions of learning about natural resources in the Kenyan context. Its other key contribution is that it provides further insight into the re-orientation of the ERM courses to embrace ESD for a broader and a more holistic approach to natural resources conservation and poverty alleviation processes that are critical for responding to socio-ecological issues and risks and development challenges in Kenya.
- Full Text:
- Date Issued: 2014
- Authors: Oteki, Jane Bosibori
- Date: 2014
- Subjects: Environmental management -- Kenya Sustainable development -- Kenya Environmental management -- Study and teaching -- Kenya Sustainable development -- Study and teaching -- Kenya Environmental education -- Study and teaching -- Kenya Environmental sciences -- Study and teaching -- Kenya Technical University of Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1964 , http://hdl.handle.net/10962/d1011611
- Description: Environmental challenges facing the world currently call for efforts that can avert eminent disasters related to these challenges. In an effort to engage in conservation, the Environmental Resource Management course at Technical University offers an opportunity to train for sustainable development in the country. However, the development and implementation of courses aimed at developing careers in sustainability in institutions of higher learning are coming under scrutiny as questions are being asked about their contributions to sustainable development. This research explored the Environmental Resource Management course to understand how it was developed and implemented to address a practitioner in the environmental resources conservation sector. The study surfaced the contradictions in the course which can be used as a lens to re-orient the course to enable a practitioner in education for sustainable development to emerge. In Kenya, vocational courses in environmental education are a career choice for secondary school leavers and those engaged in the environmental conservation sector. This study carried out at Technical University of Kenya (TU-K) between January 2009 and April 2012 aimed at exploring how a diploma course: Environmental Resource Management (ERM) enabled the learners to become practitioners in environmental resource management. It surfaced contradictions and suggested transformative approaches to re-orient the course for sustainable development. This was necessitated by the paradigm shift in environmental education from environmental conservation education that emphasised ecological studies to Education for Sustainable Development that is broader and more holistic, encompassing social, economic and environmental aspects. The course has to be re-orientated to enable a practitioner in Education for Sustainable Development (ESD) to emerge considering the United Nations Decade of Education for Sustainable Development (UNDESD, 2005-2014). The course aims at training personnel for deployment in environmental conservation and management organisations to work as resource officers/supervisors in national parks, forestry management, water management, energy development projects officers, etc. Data was gathered through document analysis, questionnaires, interviews, observation and focus group discussions. Cultural Historical Activity Theory (CHAT) was engaged in surfacing contradictions in the Environmental Resource Management learning system in terms of its development and implementation. While Communities of Practice (COP) principles were used as the ontological underpinning for the ERM course. The results indicate that the ERM course was revised between 1998 and 2002 by experts from Saskatchewan Institute of Science and Technology (SIAST) in collaboration with TU-K staff under the programme, enhancing environmental management in Kenya. The research also established that the ERM course review process was informed by sustainable development principles, as outlined in Agenda 21. Further it was realised that the Develop a Curriculum (DACUM) process was engaged to develop the learning units. This course development envisaged Competency Based Education (CBE) as the main mode of the ERM delivery. CBE is student centred and allows for multi-entry and exit. The study however realised that at implementation this approach was partially incorporated, as the country’s education system is examination oriented and time bound. The study findings indicate that most of the units taught were on ecosystem management with the social and economic aspects having less space and time, therefore the three pillars of Education for Sustainable Development were not adequately addressed in the course to enable a practitioner in the concept to emerge. Also teaching and learning in the course was found to be more theoretical than practical with little hands-on activities because the main focus of the course was to enable the learners to acquire a certificate through examination rather than gain the appropriate competencies. Although the course was found to be enhancing ESD in relation to global and local sustainability issues, there were contradictions or challenges in the system that affected full realisation of the skills, knowledge, values and attitudes. For example the exclusion of the recipient staff in the planning of the course, lack of training of the lecturers on how to train on CBE, insufficient practical field excursions devoid of community engagement, lack of funds, lack of equipment and poor coordination. This study recommends a re-orientation of the course to a more practical approach to teaching such as: • Engagement of students with the community to solve real-life environmental problems; • Mainstreaming ESD in all courses in the institutions of higher learning so that environmental concerns are addressed by everyone; • Reviewing the educational policy to encourage solving of real-life environmental problems rather than passing theoretical examinations; • Enhancing competency based learning to enable students to become competent in their areas of specialisation; • Encouraging networking and direct involvement of the students in the community instead of spending more time in class; and • Establishing a Community of Practice among the students in Higher Education Institutions to enhance conservation practices. The study contributes in-depth insight into exploring courses in Technical Vocational Education and Training institutions using Communities of Practice as a lens within the Kenyan context. It gives some empirical and explanatory insight into how learning can emerge and be expanded in Education for Sustainable Development through relevant courses such as tje Environmental Resource Management course. It also provides learning tools to work with contradictions that arise from socio-cultural and historical dimensions of learning about natural resources in the Kenyan context. Its other key contribution is that it provides further insight into the re-orientation of the ERM courses to embrace ESD for a broader and a more holistic approach to natural resources conservation and poverty alleviation processes that are critical for responding to socio-ecological issues and risks and development challenges in Kenya.
- Full Text:
- Date Issued: 2014
Comparative aspects of the reproductive biology of seabreams (Pisces: Sparidae)
- Authors: Garratt, Patrick Ashworth
- Date: 1994
- Subjects: Sparidae -- Physiology Sparidae -- Reproduction
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5245 , http://hdl.handle.net/10962/d1005088
- Description: Sexuality in seabreams (Sparidae) is considered to be more complex than in any other family of fishes. Early work indicated five reproductive styles within the family: protandry, protogyny, simultaneous hermaphroditism, rudimentary hermaphroditism and gonochorism. More recently two reproductive styles have been suggested: sex change (protandry and protogyny) and secondary gonochorism (rudimentary hermaphrodites). The need for detailed descriptions of sex differentiation, gonad development and spawning behaviour in this family has been identified by a number of workers in this field. The aims of the present study were: i) to provide accurate, detailed descriptions and comparisons of gonadal development in representatives of each reproductive style, ii) to investigate their spawning strategies, and iii) to relate these findings to current theories on hermaphroditism and sex change in fishes. Four species were investigated. Slinger, Chrysoblephus puniceus, the only known protogynous hermaphrodite in Natal. Santer, Cheimerius nufar, described in the literature as a rudimentary hermaphrodite. Riverbream, Acanthopagrus berda suspected to be a protandrous hermaphrodite. Natal stump nose, Rhabdosargus sarba, reported elsewhere as a protandrous hermaphrodite. Detailed histological analysis showed that morphological and cytological development of all gonads proceeded initially in a female direction, irrespective of reproductive style, but that differentiating gonads of protandrous and protogynous hermaphrodites could easily be distinguished from one another. Early gonadal development was similar in R. sarba and A. berda with gonadal primordia differentiating into distinctly bisexual organs. In C. puniceus and C. nufar gonadal primordia differentiated into ovaries with reduced, inert male elements in the tunica albuginea. Sex differentiation occurred relatively late (100-150mm fork length) in all the species investigated. Few cells conforming to primordial germ cells (PGC's) described in other teleosts were identified. These cells only became evident after the appearance of gonial cells and their identity is questioned. Gonial cells appeared to develop within less-electron-dense cysts of cells. Gonial cells in presumptive male and female elements could not be distinguished from one another morphologically, suggesting the bipotentiality of these cells. All R. sarba and A. berda gonads pass through a predominantly male phase and all fish function first as males, indicating protandrous sex change in both species. All C. puniceus and C. nufar gonads develop initially into ovaries. Sex change thus occurs in both species and protogyny in C. puniceus is confirmed. In C. nufar, sex change may occur before or after sexual maturity and its reproductive style remains uncertain. Investigations into the spawning habits of A. berda have shown that this species spawns inside the Kosi estuary at night. Eggs are released during peak ebb tides. Spawning occurs in large aggregations and several to many males compete to spawn with individual females. This spawning strategy does not conform to predictions made from the size advantage model for protandrous species. Chrysoblephus puniceus appears to have preferential spawning sites on down-current outer reef margins. Spawning was not observed in this species, but changes in behaviour, social structure and colour during the spawning season suggest that it may have a mating system similar to several protogynous labrids and scarids, in which territories are temporary. Cheimerius nufar has a similar mating system. Temporary territories are established by large males during the spawning season, which extends from August to November. Mating is by pair-spawning and dominant territorial males obtain a disproportionate number of matings. 'Streaking' appears to represent an alternative mating strategy for males until they attain a sufficient size to establish and defend territories. The mating pattern of C. nufar suggests that it is either a gonochorist which does not conform to current theoretical predictions; or that it is a protogynous hermaphrodite incorrectly diagnosed as a rudimentary hermaphrodite; or that protogyny in the Sparidae is an ancestral condition and C. nufar is in the process of evolutionary change from a protogynous to a gonochoristic form (or visa versa).
- Full Text:
- Date Issued: 1994
- Authors: Garratt, Patrick Ashworth
- Date: 1994
- Subjects: Sparidae -- Physiology Sparidae -- Reproduction
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5245 , http://hdl.handle.net/10962/d1005088
- Description: Sexuality in seabreams (Sparidae) is considered to be more complex than in any other family of fishes. Early work indicated five reproductive styles within the family: protandry, protogyny, simultaneous hermaphroditism, rudimentary hermaphroditism and gonochorism. More recently two reproductive styles have been suggested: sex change (protandry and protogyny) and secondary gonochorism (rudimentary hermaphrodites). The need for detailed descriptions of sex differentiation, gonad development and spawning behaviour in this family has been identified by a number of workers in this field. The aims of the present study were: i) to provide accurate, detailed descriptions and comparisons of gonadal development in representatives of each reproductive style, ii) to investigate their spawning strategies, and iii) to relate these findings to current theories on hermaphroditism and sex change in fishes. Four species were investigated. Slinger, Chrysoblephus puniceus, the only known protogynous hermaphrodite in Natal. Santer, Cheimerius nufar, described in the literature as a rudimentary hermaphrodite. Riverbream, Acanthopagrus berda suspected to be a protandrous hermaphrodite. Natal stump nose, Rhabdosargus sarba, reported elsewhere as a protandrous hermaphrodite. Detailed histological analysis showed that morphological and cytological development of all gonads proceeded initially in a female direction, irrespective of reproductive style, but that differentiating gonads of protandrous and protogynous hermaphrodites could easily be distinguished from one another. Early gonadal development was similar in R. sarba and A. berda with gonadal primordia differentiating into distinctly bisexual organs. In C. puniceus and C. nufar gonadal primordia differentiated into ovaries with reduced, inert male elements in the tunica albuginea. Sex differentiation occurred relatively late (100-150mm fork length) in all the species investigated. Few cells conforming to primordial germ cells (PGC's) described in other teleosts were identified. These cells only became evident after the appearance of gonial cells and their identity is questioned. Gonial cells appeared to develop within less-electron-dense cysts of cells. Gonial cells in presumptive male and female elements could not be distinguished from one another morphologically, suggesting the bipotentiality of these cells. All R. sarba and A. berda gonads pass through a predominantly male phase and all fish function first as males, indicating protandrous sex change in both species. All C. puniceus and C. nufar gonads develop initially into ovaries. Sex change thus occurs in both species and protogyny in C. puniceus is confirmed. In C. nufar, sex change may occur before or after sexual maturity and its reproductive style remains uncertain. Investigations into the spawning habits of A. berda have shown that this species spawns inside the Kosi estuary at night. Eggs are released during peak ebb tides. Spawning occurs in large aggregations and several to many males compete to spawn with individual females. This spawning strategy does not conform to predictions made from the size advantage model for protandrous species. Chrysoblephus puniceus appears to have preferential spawning sites on down-current outer reef margins. Spawning was not observed in this species, but changes in behaviour, social structure and colour during the spawning season suggest that it may have a mating system similar to several protogynous labrids and scarids, in which territories are temporary. Cheimerius nufar has a similar mating system. Temporary territories are established by large males during the spawning season, which extends from August to November. Mating is by pair-spawning and dominant territorial males obtain a disproportionate number of matings. 'Streaking' appears to represent an alternative mating strategy for males until they attain a sufficient size to establish and defend territories. The mating pattern of C. nufar suggests that it is either a gonochorist which does not conform to current theoretical predictions; or that it is a protogynous hermaphrodite incorrectly diagnosed as a rudimentary hermaphrodite; or that protogyny in the Sparidae is an ancestral condition and C. nufar is in the process of evolutionary change from a protogynous to a gonochoristic form (or visa versa).
- Full Text:
- Date Issued: 1994
The thermodynamics of solutions and binary liquid mixtures
- Authors: Mercer-Chalmers, June Dawn
- Date: 1993
- Subjects: Thermodynamics Liquids Solution (Chemistry)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4390 , http://hdl.handle.net/10962/d1005055
- Description: The thesis is presented in two parts. In part one, the excess thermodynamic properties have been determined for several binary liquid mixtures, with the aim of testing theories of liquid mixtures. The excess molar enthalpies, Hem, have been determined using an LKB flow microcalorimeter, and the excess molar volumes, Vem, have been determined using an Anton Paar densitometer. The HemS and VemS have been measured at 298.15 K for binary systems involving an alkanol (methanol, ethanol, I-propanol, 2-propanol) mixed with a hydrocarbon (l-hexene, I-heptene, l-octene, I-hexyne, I-heptyne, l-octyne, toluene, mesitylene, 0-, m-, or p-xylene, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane). The results show trends relating to the degree of unsaturation, or size, of component molecules as well as the position of the hydroxyl group on the alkanol. Measurements were also made on mixtures involving an (n-alkane + a pseudo-n-alkane) and ( a cYcloalkane + a pseudo-cycloalkane). Two theories of liquid mixtures were tested in this work. The first theory tested was the theory of Congruency. This theory was tested, by means of a null test, on a novel set of mixtures involving an n-alkane (hexane, heptane, octane, decane, dodecane) + a pseudo-nalkane,and mixtures of a cycloalkane (cyclopentane, cyclohexane, cycloheptane, cyclooctane)+ a pseudo-cycloalkane. Deviations from the theory was less than the experimental error for the (n-alkane + pseudo-n-alkane) mixtures. However, significant deviations were observed for the mixtures of (a cycloalkane + a pseudo-cycloalkane). The second theory tested was the Flory theory, which has been used to predict the excess molar enthalpies and excess molar volumes for the mixtures involving (a 1-alkene, or 1-alkyne, or methyl-substituted benzene) + an alkanol. The results show that the theory does not hold for hydrocarbon mixtures involving an alkanol. In the second part of this thesis, the partial molar volumes, at infinite dilution, of binary solution involving a solid solute (18-crown-6 ether, dibenzo-18-crown-6 ether, dicyclohexanov 18-crown-6 ether, 15-crown-5 ether, or cryptand-222) are determined in various solvents. The results were repeated with a view to determine the volume changes at infinite dilution upon complexation, ΔV∞ of the crown ether or cryptand with a metal halide salt, MX (NaCl, NaI, KCl, KI, CsCl, CsI). The ΔV∞ results were compared with results in the literature for cryptand-222 (c-222) and dibenzo-18-crown-6 ether (B₂CE6) complexed with MX, and the study was extended to include further MX complexes with c-222 and B₂CE6, as well as MX complexes with 15-crown-5 ether and dicyclohexano-18-crown-6 ether. ΔV∞ results were correlated with the Hepler prediction of the electrostriction solvent effect.
- Full Text:
- Date Issued: 1993
- Authors: Mercer-Chalmers, June Dawn
- Date: 1993
- Subjects: Thermodynamics Liquids Solution (Chemistry)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4390 , http://hdl.handle.net/10962/d1005055
- Description: The thesis is presented in two parts. In part one, the excess thermodynamic properties have been determined for several binary liquid mixtures, with the aim of testing theories of liquid mixtures. The excess molar enthalpies, Hem, have been determined using an LKB flow microcalorimeter, and the excess molar volumes, Vem, have been determined using an Anton Paar densitometer. The HemS and VemS have been measured at 298.15 K for binary systems involving an alkanol (methanol, ethanol, I-propanol, 2-propanol) mixed with a hydrocarbon (l-hexene, I-heptene, l-octene, I-hexyne, I-heptyne, l-octyne, toluene, mesitylene, 0-, m-, or p-xylene, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane). The results show trends relating to the degree of unsaturation, or size, of component molecules as well as the position of the hydroxyl group on the alkanol. Measurements were also made on mixtures involving an (n-alkane + a pseudo-n-alkane) and ( a cYcloalkane + a pseudo-cycloalkane). Two theories of liquid mixtures were tested in this work. The first theory tested was the theory of Congruency. This theory was tested, by means of a null test, on a novel set of mixtures involving an n-alkane (hexane, heptane, octane, decane, dodecane) + a pseudo-nalkane,and mixtures of a cycloalkane (cyclopentane, cyclohexane, cycloheptane, cyclooctane)+ a pseudo-cycloalkane. Deviations from the theory was less than the experimental error for the (n-alkane + pseudo-n-alkane) mixtures. However, significant deviations were observed for the mixtures of (a cycloalkane + a pseudo-cycloalkane). The second theory tested was the Flory theory, which has been used to predict the excess molar enthalpies and excess molar volumes for the mixtures involving (a 1-alkene, or 1-alkyne, or methyl-substituted benzene) + an alkanol. The results show that the theory does not hold for hydrocarbon mixtures involving an alkanol. In the second part of this thesis, the partial molar volumes, at infinite dilution, of binary solution involving a solid solute (18-crown-6 ether, dibenzo-18-crown-6 ether, dicyclohexanov 18-crown-6 ether, 15-crown-5 ether, or cryptand-222) are determined in various solvents. The results were repeated with a view to determine the volume changes at infinite dilution upon complexation, ΔV∞ of the crown ether or cryptand with a metal halide salt, MX (NaCl, NaI, KCl, KI, CsCl, CsI). The ΔV∞ results were compared with results in the literature for cryptand-222 (c-222) and dibenzo-18-crown-6 ether (B₂CE6) complexed with MX, and the study was extended to include further MX complexes with c-222 and B₂CE6, as well as MX complexes with 15-crown-5 ether and dicyclohexano-18-crown-6 ether. ΔV∞ results were correlated with the Hepler prediction of the electrostriction solvent effect.
- Full Text:
- Date Issued: 1993
A study of the educational thought of Rudolf Steiner
- Authors: Blunt, Richard John Scawen
- Date: 1983
- Subjects: Steiner, Rudolf, 1861-1925 Education -- Philosophy
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1886 , http://hdl.handle.net/10962/d1005932
- Full Text:
- Date Issued: 1983
- Authors: Blunt, Richard John Scawen
- Date: 1983
- Subjects: Steiner, Rudolf, 1861-1925 Education -- Philosophy
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1886 , http://hdl.handle.net/10962/d1005932
- Full Text:
- Date Issued: 1983
The relationship of academic aptitude and study habits to academic success : a study of first year students' experience of academic life with specific reference to the University of Fort Hare
- Authors: Penny, Alan Joseph
- Date: 1980
- Subjects: Academic achievement , Student adjustment -- South Africa , College students, Black -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1379 , http://hdl.handle.net/10962/d1001445
- Description: Any enquiry follows some incident which has prompted the question that leads to the enquiry. This study was prompted by a review of the 1974 first year examination results at the University of Fort Hare. The average percentage pass rate for that year was 59.3%. The cynic may remark that this is no different to the first year pass rate at white South African universities (cf. Erens and Louw, 1978), but when it is realised that students entering Fort Hare, or any other black university for that matter, are a highly select group, these figures have more Impact. The consequences of failure in terms of the wastage of human potential are immense (cf. Auerbach, 1977) but are more critical when this occurs, as It does, "... in a society which is competitive rather than co-operative, where people are for ever being classified according to what they have rather than that they can contribute and where competition plus classification inevitably breeds fears." Bligh (1978). A review of the first year examination results for the five years from 1971 revealed an average pass rate of 55.5% and for 1976, 1977 and 1978 a marked decline to 39.32%. For the earlier period, Downing (1977) found that 19.69% of students completed their degree courses In the minimum number of years. For the latter period (1976 to 1978) this has dropped to 16.3%, which, with the figure for the earlier period, suggests that whilst the failure rate may be highest at the end of the first year, in subsequent years it is also high. In this respect Fort Hare differs from white universities where about 75% of students complete their degrees in minimum time (cf. Erens and Louw, 1978)
- Full Text:
- Date Issued: 1980
- Authors: Penny, Alan Joseph
- Date: 1980
- Subjects: Academic achievement , Student adjustment -- South Africa , College students, Black -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1379 , http://hdl.handle.net/10962/d1001445
- Description: Any enquiry follows some incident which has prompted the question that leads to the enquiry. This study was prompted by a review of the 1974 first year examination results at the University of Fort Hare. The average percentage pass rate for that year was 59.3%. The cynic may remark that this is no different to the first year pass rate at white South African universities (cf. Erens and Louw, 1978), but when it is realised that students entering Fort Hare, or any other black university for that matter, are a highly select group, these figures have more Impact. The consequences of failure in terms of the wastage of human potential are immense (cf. Auerbach, 1977) but are more critical when this occurs, as It does, "... in a society which is competitive rather than co-operative, where people are for ever being classified according to what they have rather than that they can contribute and where competition plus classification inevitably breeds fears." Bligh (1978). A review of the first year examination results for the five years from 1971 revealed an average pass rate of 55.5% and for 1976, 1977 and 1978 a marked decline to 39.32%. For the earlier period, Downing (1977) found that 19.69% of students completed their degree courses In the minimum number of years. For the latter period (1976 to 1978) this has dropped to 16.3%, which, with the figure for the earlier period, suggests that whilst the failure rate may be highest at the end of the first year, in subsequent years it is also high. In this respect Fort Hare differs from white universities where about 75% of students complete their degrees in minimum time (cf. Erens and Louw, 1978)
- Full Text:
- Date Issued: 1980
German immigration to the Cape, with special reference to (a) the German military settlers of 1857; and (b) the German immigrants of 1858
- Authors: Schnell, E L G
- Date: 1952
- Subjects: Germans -- South Africa -- Cape of Good Hope , Immigrants -- South Africa -- Cape of Good Hope , Cape of Good Hope (South Africa) -- History , Eastern Cape (South Africa) -- History
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2613 , http://hdl.handle.net/10962/d1013168
- Description: South Africa is a multi-racial society in more than one sense. There are the broad divisions of Colour, but in addition there are further divisions within each group. The European section is mostly of Dutch and British origin, but there are important other strains, notably the French and the German. The history of the Dutch and British sections has been written, and that of the French too, but the story of the German element is still incomplete. Preface.
- Full Text:
- Date Issued: 1952
- Authors: Schnell, E L G
- Date: 1952
- Subjects: Germans -- South Africa -- Cape of Good Hope , Immigrants -- South Africa -- Cape of Good Hope , Cape of Good Hope (South Africa) -- History , Eastern Cape (South Africa) -- History
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2613 , http://hdl.handle.net/10962/d1013168
- Description: South Africa is a multi-racial society in more than one sense. There are the broad divisions of Colour, but in addition there are further divisions within each group. The European section is mostly of Dutch and British origin, but there are important other strains, notably the French and the German. The history of the Dutch and British sections has been written, and that of the French too, but the story of the German element is still incomplete. Preface.
- Full Text:
- Date Issued: 1952
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