Research projects
- Authors: Adusei-Owusu, James
- Date: 2001
- Subjects: Constructivism (Education) , Review literature , College students -- Study and teaching , Teaching -- Methods , Competency based education -- Eastern Cape (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1740 , http://hdl.handle.net/10962/d1003624 , Constructivism (Education) , Review literature , College students -- Study and teaching , Teaching -- Methods , Competency based education -- Eastern Cape (South Africa)
- Description: RESEARCH PROJECTS: 1 RESEARCH PROJECT ONE: A literature review: Constructivism: An alternate approach to teaching and learning. Abstract The constructivist perspectives on learning have helped enhance science educators' understanding of how students make sense of their lived experiences. Constructivism purports to be a transformation of the traditional curriculum. As such this article starts with a brief overview of behaviorism: the scientific approach to education. The main tenets underlying constructivism, how constructivism guides educators to change their classroom practice, and the implications to science teaching have been reviewed. 2 RESEARCH PROJECT TWO (Empirical study): Being Constructive: College students' learning of work and heat as aspects of the energy concept based a constructivist approach. Abstract This study is an extension of a literature review on constructivism as an alternate teaching and learning approach discussed in research project one. It is an empirical study concerning the use of a learning module based on a constructivist approach to develop pre-service student teachers' understanding of work and heat as aspects of the energy concept. The data consisted mainly of transcripts of students' interviews, written responses to questionnaires designed in the form of a worksheet, and comments from non-participant observers and students. The results seem to suggest that a carefully designed learning module based on a constructivist teaching and learning approach may be a valuable tool in developing pre-service student teachers' understanding of work and heat. 3 RESEARCH PROJECT THREE (Empirical study): A College in transition: A case study of the readiness of a college in the Eastern Cape province to implement Outcomes-Based Education in an Education Development centre. Abstract Curriculum 2005 premised on Outcomes-Based Education is the new curriculum framework for South Africa. It signifies a paradigm shift in education from the traditional 'telling-listening' relationship between the teacher and the learner to one that emphasises leamer-centred approach to the teaching process. Teachers, though recognized as crucial to the educational transformation process in the country have also being identified as ill-equipped to meet the challenges posed by Outcomes-Based Education. This study starts with a brief overview of the South African curriculum and the main tenets underlying Outcomes-Based Education. The institutional conditions and whether the lecturers at a college in the Eastern Cape province perceive the need for a change in their classroom practice were also investigated. Bearing in mind the need for further research to validate the findings of this study, positive indicators that emerged from the study suggest the readiness of the college to implement Outcomes-Based Education at the proposed Education Development Centre.
- Full Text:
- Date Issued: 2001
- Authors: Adusei-Owusu, James
- Date: 2001
- Subjects: Constructivism (Education) , Review literature , College students -- Study and teaching , Teaching -- Methods , Competency based education -- Eastern Cape (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1740 , http://hdl.handle.net/10962/d1003624 , Constructivism (Education) , Review literature , College students -- Study and teaching , Teaching -- Methods , Competency based education -- Eastern Cape (South Africa)
- Description: RESEARCH PROJECTS: 1 RESEARCH PROJECT ONE: A literature review: Constructivism: An alternate approach to teaching and learning. Abstract The constructivist perspectives on learning have helped enhance science educators' understanding of how students make sense of their lived experiences. Constructivism purports to be a transformation of the traditional curriculum. As such this article starts with a brief overview of behaviorism: the scientific approach to education. The main tenets underlying constructivism, how constructivism guides educators to change their classroom practice, and the implications to science teaching have been reviewed. 2 RESEARCH PROJECT TWO (Empirical study): Being Constructive: College students' learning of work and heat as aspects of the energy concept based a constructivist approach. Abstract This study is an extension of a literature review on constructivism as an alternate teaching and learning approach discussed in research project one. It is an empirical study concerning the use of a learning module based on a constructivist approach to develop pre-service student teachers' understanding of work and heat as aspects of the energy concept. The data consisted mainly of transcripts of students' interviews, written responses to questionnaires designed in the form of a worksheet, and comments from non-participant observers and students. The results seem to suggest that a carefully designed learning module based on a constructivist teaching and learning approach may be a valuable tool in developing pre-service student teachers' understanding of work and heat. 3 RESEARCH PROJECT THREE (Empirical study): A College in transition: A case study of the readiness of a college in the Eastern Cape province to implement Outcomes-Based Education in an Education Development centre. Abstract Curriculum 2005 premised on Outcomes-Based Education is the new curriculum framework for South Africa. It signifies a paradigm shift in education from the traditional 'telling-listening' relationship between the teacher and the learner to one that emphasises leamer-centred approach to the teaching process. Teachers, though recognized as crucial to the educational transformation process in the country have also being identified as ill-equipped to meet the challenges posed by Outcomes-Based Education. This study starts with a brief overview of the South African curriculum and the main tenets underlying Outcomes-Based Education. The institutional conditions and whether the lecturers at a college in the Eastern Cape province perceive the need for a change in their classroom practice were also investigated. Bearing in mind the need for further research to validate the findings of this study, positive indicators that emerged from the study suggest the readiness of the college to implement Outcomes-Based Education at the proposed Education Development Centre.
- Full Text:
- Date Issued: 2001
Rural resettlement scheme evaluation: a case study of the Mfengu in Tsitsikamma
- Authors: Fakudze, Churchill M
- Date: 2001
- Subjects: Land settlement , Land settlement -- South Africa -- Tsitsikamma , Land settlement -- Developing countries , Land settlement -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3309 , http://hdl.handle.net/10962/d1003097 , Land settlement , Land settlement -- South Africa -- Tsitsikamma , Land settlement -- Developing countries , Land settlement -- South Africa
- Description: In 1997 South Africa came out with a policy aimed at addressing the legacy of apartheid in respect of an unequal division of land in the country. About 3.5 million people were moved from rural and urban areas between 1960 and 1980 and deposited in the reserves or areas designed for the exclusive occupation of black people. The new land policy attempts to deal with the resultant problems. The policy advocates a three-pronged approach to land reform encompassing (i) land restitution, (ii) land redistribution and (iii) land tenure reform. A number of projects have been carried out under these three aspects. This study aims to investigate and evaluate the results of a completed land restitution case. The Mfengu of Tsitsikamma was chosen as a case study because the people have moved back and are now living on their land. The Mfengu were dispossessed of their land in 1977 by the apartheid government and their land was returned in 1994. Although this case was processed outside of the land restitution legislation (Restitution of Land Rights Act, 22 of 1994), all restitution cases where people return to their original land have to deal with the problems of resettlement. From its involvement in various involuntary resettlement projects, the World Bank concluded that the new communities of resettlers should be designed as a viable settlement system equipped with infrastructure and services and integrated in the regional socio-economic context. The host communities receiving the resettlers should be assisted to overcome possible adverse social and environmental effects from the increased population density. These concerns are valid for the South African situation, and the question is, whether this resettlement encapsulates the above. The goals of the research are twofold. To evaluate the efficiency and effectiveness of the resettlement project and its sustainability. In particular focussing on the constraints to the implementation of the land policy. Research questions include the following: How was the project carried out? Is the resettlement integrated into the socio-economic and development planning of the area? How viable and sustainable is the new settlement? What are the major problems and challenges facing this area and how can they be overcome?
- Full Text:
- Date Issued: 2001
- Authors: Fakudze, Churchill M
- Date: 2001
- Subjects: Land settlement , Land settlement -- South Africa -- Tsitsikamma , Land settlement -- Developing countries , Land settlement -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3309 , http://hdl.handle.net/10962/d1003097 , Land settlement , Land settlement -- South Africa -- Tsitsikamma , Land settlement -- Developing countries , Land settlement -- South Africa
- Description: In 1997 South Africa came out with a policy aimed at addressing the legacy of apartheid in respect of an unequal division of land in the country. About 3.5 million people were moved from rural and urban areas between 1960 and 1980 and deposited in the reserves or areas designed for the exclusive occupation of black people. The new land policy attempts to deal with the resultant problems. The policy advocates a three-pronged approach to land reform encompassing (i) land restitution, (ii) land redistribution and (iii) land tenure reform. A number of projects have been carried out under these three aspects. This study aims to investigate and evaluate the results of a completed land restitution case. The Mfengu of Tsitsikamma was chosen as a case study because the people have moved back and are now living on their land. The Mfengu were dispossessed of their land in 1977 by the apartheid government and their land was returned in 1994. Although this case was processed outside of the land restitution legislation (Restitution of Land Rights Act, 22 of 1994), all restitution cases where people return to their original land have to deal with the problems of resettlement. From its involvement in various involuntary resettlement projects, the World Bank concluded that the new communities of resettlers should be designed as a viable settlement system equipped with infrastructure and services and integrated in the regional socio-economic context. The host communities receiving the resettlers should be assisted to overcome possible adverse social and environmental effects from the increased population density. These concerns are valid for the South African situation, and the question is, whether this resettlement encapsulates the above. The goals of the research are twofold. To evaluate the efficiency and effectiveness of the resettlement project and its sustainability. In particular focussing on the constraints to the implementation of the land policy. Research questions include the following: How was the project carried out? Is the resettlement integrated into the socio-economic and development planning of the area? How viable and sustainable is the new settlement? What are the major problems and challenges facing this area and how can they be overcome?
- Full Text:
- Date Issued: 2001
Sapphic experience: lesbian gender identity development and diversity
- Authors: Crowley, Michelle Laureen
- Date: 2001
- Subjects: Lesbian couples Gender identity Sexual orientation Heterosexual women Lesbian feminists
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2956 , http://hdl.handle.net/10962/d1002465
- Description: This dissertation explores lesbian experience, or the psychological meaning of being lesbian from the point of view of women who call themselves lesbian. The researcher suspended the binary paradigm of sex and gender, and argued that lesbians' identity development must be understood against the background of how patriarchy understands the category 'woman' through history. Towards this purpose the pOSition of women in the West, as well as contemporary images and literature about lesbians, was reviewed. On the basis of this review questions about lesbian gender construction, lesbian identity development and lesbian individuation were identified. In order to access the psychological meaning of being lesbian, or lesbian experience from the inside out, the dream-series of three lesbians constituted an empirical basis for further exploration. These dream-series were amplified with intensive face-to-face interviews, transcribed, and subjected to a hermeneutic-phenomenological inductive method. Common inter-case concerns were identified and synthesized. In dialogue with the literature reviewed, twenty-two statements of meaning about being lesbian were distilled. These revealed two possible constructions of gender for primary lesbians. In addition, primary lesbians involved in the research demonstrated remarkable flexibility with respect to their gender orientations and gender identifications, were in the process of integrating with and differentiating from different aspects of their masculine and feminine potentials, and developed and negotiated their gender identities in relationship to both their lovers and friends. The explication also revealed that participants identified with archetypal aspects of the father that their fathers' did not express, and desired archetypal aspects of the mother that their mother's did not express. Finally, in so much as the method distinguished ~ sex, sexual identity and sexual orientation from gender, gender identity, gender identification and gender orientation, it may prove useful for exploring gender in heterosexual relating.
- Full Text:
- Date Issued: 2001
- Authors: Crowley, Michelle Laureen
- Date: 2001
- Subjects: Lesbian couples Gender identity Sexual orientation Heterosexual women Lesbian feminists
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2956 , http://hdl.handle.net/10962/d1002465
- Description: This dissertation explores lesbian experience, or the psychological meaning of being lesbian from the point of view of women who call themselves lesbian. The researcher suspended the binary paradigm of sex and gender, and argued that lesbians' identity development must be understood against the background of how patriarchy understands the category 'woman' through history. Towards this purpose the pOSition of women in the West, as well as contemporary images and literature about lesbians, was reviewed. On the basis of this review questions about lesbian gender construction, lesbian identity development and lesbian individuation were identified. In order to access the psychological meaning of being lesbian, or lesbian experience from the inside out, the dream-series of three lesbians constituted an empirical basis for further exploration. These dream-series were amplified with intensive face-to-face interviews, transcribed, and subjected to a hermeneutic-phenomenological inductive method. Common inter-case concerns were identified and synthesized. In dialogue with the literature reviewed, twenty-two statements of meaning about being lesbian were distilled. These revealed two possible constructions of gender for primary lesbians. In addition, primary lesbians involved in the research demonstrated remarkable flexibility with respect to their gender orientations and gender identifications, were in the process of integrating with and differentiating from different aspects of their masculine and feminine potentials, and developed and negotiated their gender identities in relationship to both their lovers and friends. The explication also revealed that participants identified with archetypal aspects of the father that their fathers' did not express, and desired archetypal aspects of the mother that their mother's did not express. Finally, in so much as the method distinguished ~ sex, sexual identity and sexual orientation from gender, gender identity, gender identification and gender orientation, it may prove useful for exploring gender in heterosexual relating.
- Full Text:
- Date Issued: 2001
Sedimentology of the Karoo Supergroup in the Tuli Basin (Limpompo River area, South Africa)
- Authors: Bordy, Emese M
- Date: 2001
- Subjects: River sediments -- South Africa Sedimentology Limpopo river Sedimentology -- Limpopo river Limpopo river (South africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4999 , http://hdl.handle.net/10962/d1005612
- Description: The sedimentary rocks of the Karoo Supergroup in the Tuli Basin (South Africa) consist of various terrigenous clastic and chemical deposits (parabreccias, conglo-breccias, conglomerates, sandstones, fine-grained sediments, calcretes and silc~etes). Four stratigraphic units were identified: the Basal, Middle and· Upper Units, and the CI~rens Formation. The palaeo-environmental reconstructions of the four stratigraphic units are based on evidence provided by primary sedimentary structures, palaeo-flow measurements, clast size/shape analysis, petrographic studies, palaeontological findings, borehole data and stratigraphic relations. The facies associations of the Basal Unit are interpreted as colluvial fan and low sinuosity, braid~d river channel with coal-bearing overbank and thaw-lake deposits. The interpreted depositional environment implies a cold climate, non-glacial subarctic fluvio-Iacustrine system. The current indicators of the palaeo-river system suggest flow direction from ENE to WSW. The lithologies of the Basal Unit are very similar to the deposits of the fluvial interval in the Vryheid Formation (Ecca Group) of the main Karoo Basin. There is no indubitable evidence for glacial activity (e.g. striated pavements or clasts, varvites, etc.), therefore the presence of unequivocal Dwyka Group correlatives in the Tuli Basin remains uncertain. The sedimentary structures and palaeo-current analysis indicate that the beds of the Middle Unit were deposited by an ancient river system flowing in a north-northwesterly direction. A lack of good quality exposures did not allow the reconstruction of the fluvial style, but the available data indicate a high-energy, perhaps braided fluvial system. The lack of bio- and chronostr~~igraphic control hampers precise correlation and enables only the lithocorrelation of the Middle Unit with other braided river systems either in the Beaufort Group or in the Molteno Formation of the main Karoo Basin. The depositional environment of the Upper Unit is interpreted as a low-sinuosity, ephemeral stream system with calcretes and silcretes in the dinosaur-inhabited overbank area. During the deposition of the unit, the climate was semi-arid with sparse precipitation resulting -iFlhighmagnitude, low-frequency devastating flash floods. The sediments were built out from a distant northwesterly source to the southeast. The unambiguous correspondence between the Upper Unit and the Elliot Formation (main Karoo Basin) is provided by lithological similarities and prosauropod dinosaurs remains. The palaeo-geographic picture of the Clarens Fonnation indicates a westerly windsdominated erg environment with migrating transverse dune types. The ephemeral stream deposits, fossil wood and trace fossils are only present in the lower part of the Formation, indicating that the wet-desert conditions were progressively replaced by dry-desert conditions. Based on lithological and palaeontological evidence, the Formation correlates with the Clarens Formation in the main Karoo Basin. At this stage, it remains difficult to establish the exact cause of the regional palaeo-slope changes during the deposition of the Karoo Supergroup in the Tuli Basin. It is probable that foreland system tectonics, which affected the lower part of the Supergroup (Basal Unit and Middle Unit?), were replaced by incipient continental extension and rift related tectonic movements in the Middle and Upper Units, and Clarens Formation.
- Full Text:
- Date Issued: 2001
- Authors: Bordy, Emese M
- Date: 2001
- Subjects: River sediments -- South Africa Sedimentology Limpopo river Sedimentology -- Limpopo river Limpopo river (South africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4999 , http://hdl.handle.net/10962/d1005612
- Description: The sedimentary rocks of the Karoo Supergroup in the Tuli Basin (South Africa) consist of various terrigenous clastic and chemical deposits (parabreccias, conglo-breccias, conglomerates, sandstones, fine-grained sediments, calcretes and silc~etes). Four stratigraphic units were identified: the Basal, Middle and· Upper Units, and the CI~rens Formation. The palaeo-environmental reconstructions of the four stratigraphic units are based on evidence provided by primary sedimentary structures, palaeo-flow measurements, clast size/shape analysis, petrographic studies, palaeontological findings, borehole data and stratigraphic relations. The facies associations of the Basal Unit are interpreted as colluvial fan and low sinuosity, braid~d river channel with coal-bearing overbank and thaw-lake deposits. The interpreted depositional environment implies a cold climate, non-glacial subarctic fluvio-Iacustrine system. The current indicators of the palaeo-river system suggest flow direction from ENE to WSW. The lithologies of the Basal Unit are very similar to the deposits of the fluvial interval in the Vryheid Formation (Ecca Group) of the main Karoo Basin. There is no indubitable evidence for glacial activity (e.g. striated pavements or clasts, varvites, etc.), therefore the presence of unequivocal Dwyka Group correlatives in the Tuli Basin remains uncertain. The sedimentary structures and palaeo-current analysis indicate that the beds of the Middle Unit were deposited by an ancient river system flowing in a north-northwesterly direction. A lack of good quality exposures did not allow the reconstruction of the fluvial style, but the available data indicate a high-energy, perhaps braided fluvial system. The lack of bio- and chronostr~~igraphic control hampers precise correlation and enables only the lithocorrelation of the Middle Unit with other braided river systems either in the Beaufort Group or in the Molteno Formation of the main Karoo Basin. The depositional environment of the Upper Unit is interpreted as a low-sinuosity, ephemeral stream system with calcretes and silcretes in the dinosaur-inhabited overbank area. During the deposition of the unit, the climate was semi-arid with sparse precipitation resulting -iFlhighmagnitude, low-frequency devastating flash floods. The sediments were built out from a distant northwesterly source to the southeast. The unambiguous correspondence between the Upper Unit and the Elliot Formation (main Karoo Basin) is provided by lithological similarities and prosauropod dinosaurs remains. The palaeo-geographic picture of the Clarens Fonnation indicates a westerly windsdominated erg environment with migrating transverse dune types. The ephemeral stream deposits, fossil wood and trace fossils are only present in the lower part of the Formation, indicating that the wet-desert conditions were progressively replaced by dry-desert conditions. Based on lithological and palaeontological evidence, the Formation correlates with the Clarens Formation in the main Karoo Basin. At this stage, it remains difficult to establish the exact cause of the regional palaeo-slope changes during the deposition of the Karoo Supergroup in the Tuli Basin. It is probable that foreland system tectonics, which affected the lower part of the Supergroup (Basal Unit and Middle Unit?), were replaced by incipient continental extension and rift related tectonic movements in the Middle and Upper Units, and Clarens Formation.
- Full Text:
- Date Issued: 2001
Stratigraphy and geochemistry of the Makganyene formation, Transvaal supergroup, Northern Cape, South Africa
- Authors: Polteau, Stéphane
- Date: 2001
- Subjects: Geology, Stratigraphic -- South Africa -- Northern Cape , Geochemistry -- South Africa -- Northern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5003 , http://hdl.handle.net/10962/d1005616 , Geology, Stratigraphic -- South Africa -- Northern Cape , Geochemistry -- South Africa -- Northern Cape
- Description: The Makganyene Formation forms the base of the Postmasburg Group in the Transvaal Supergroup of the Northern Cape Province. The Makganyene Formation has diamictite as the main rock type, but siltstone, sandstone, shale, and iron-formations are also present. A glacial origin has been proposed in the past due to the presence of dropstones, faceted and striated pebbles. Typically, the Makganyene Formation contains banded iron-formations interbedded with clastic rocks (shale, siltstone, sandstone and diamictites) at the contact with the underlying iron-formations. This transitional zone is generally overlain by massive or layered diamictites which contain poorly sorted clasts (mainly chert) within a shaly matrix. Striated pebbles have been found during field work, and dropstones have been observed in diamictites and banded iron-formations during the study. The top of the Makganyene Formation contains graded cycles interbedded with diamictites and thin layers of andesitic lavas from the Ongeluk Formation. The basal contact of the Makganyene Formation with the underlying Koegas Subgroup was described as unconformable by previous workers. However field work localised in the Rooinekke area shows a broadly conformable and interbedded contact with the underlying Koegas Subgroup. As described above, banded iron-formations are interbedded with the clastic rocks of the Makganyene Formation. Moreover, boreholes from the Sishen area display the same interbedding at the base of the Makganyene Formation. This suggests that no significant time gap is present in the whole succession between the Ghaap and Postmasburg Group. The Transvaal Supergroup in the Northern Cape displays the following succession : carbonates-BIFs-diamictites/ lava-BIFs-carbonates. The Makganyene Formation is thus at the centre of a symmetrical lithologic succession. Bulk rock compositions show that the diamictites have a similar composition to banded iron-formation with regard to their major element contents. Banded iron-formations acted as a source for the diamictites with carbonates and igneous rocks representing minor components. Differences in bulk composition between the Sishen and Matsap areas emphasize that the source of the diamictite was very localised. The Chemical Index of Alteration (CIA) has been calculated, but since the source dominant rock was iron-formation, this index cannot be usefully applied to the diamictites. ACN, A-CN-K, and A-CNK-FM diagrams confer a major importance in sorting processes due to the separation between the fine and coarse diamictites. The interbedded iron-formations display little clastic contamination indicating deposition in clear water conditions. However, dropstones are present in one borehole from the Matsap area, indicating that iron-formation took place under ice cover, or at least under icebergs. Stable isotope studies show that the iron-formations, interbedded towards the base of the Makganyene Formation, have similar values to the iron-formations of the Koegas Subgroup. As a result of the above observations, new correlations are proposed in this study, relating the different Transvaal Supergroup basins located on the Kaapvaal Craton. The Pretoria Group of the Transvaal Basin has no correlative in the Griqualand West Basin, and the Postmasburg Group of the Northern Cape Basin has no lateral equivalent in the Transvaal Basin. These changes have been made to overcome problems present in the current correlations between those two basins. The Makganyene Formation correlates with the Huronian glaciations which occurred between 2.4 and 2.2 Ga ago in North America. Another Precambrian glaciation is the worldwide and well-studied Neoproterozoic glaciation (640 Ma). At each of these glaciations, major banded iron-formation deposition took place with associated deposition of sedimentary manganese in post-glacial positions. The central position of the Makganyene Formation within the Transvaal Supergroup in the Northern Cape emphasizes this glacial climatic dependence of paleoproterozoic banded iron-formation and manganese deposition. However these two Precambrian glaciations are interpreted in paleomagnetic studies as having occurred near to the equator. The controversial theory of the Snowball Earth has been proposed which proposes that the Earth was entirely frozen from pole to pole. Results from field work, sedimentology, petrography and geochemistry were integrated in a proposed depositional model of the Makganyene Formation occurring at the symmetrical centre of the lithologic succession of the Transvaal Supergroup. At the beginning of the Makganyene glaciation, a regression occurred and glacial advance took place. The diamictites are mostly interpreted as being deposited from wet-based glaciers, probably tidewater glaciers, where significant slumping and debris flows occurred. Any transgression would cause a glacial retreat by rapid calving, re-establishing the chemical sedimentation of banded iron-formations. These sea-level variations are responsible for the interbedding of these different types of rocks (clastic and chemical). The end of the Makganyene glacial event is characterised by subaerial eruptions of andesitic lava of the Ongeluk Formation bringing ashes into the basin. Banded iron-formation and associated manganese accumulations are climate-dependant. Glacial events are responsible for the build up of metallic ions such as iron and manganese in solution in deep waters. A warmer climate would induce a transgression and precipitation of these metallic ions when Eh conditions are favourable. In the Transvaal Supergroup, the climatic variations from warm to cold, and cold to warm are expressed by the lithologic succession. The warm climates are represented by carbonates. Cold climates are represented by banded iron-formations and the peak in cold climate represented by the diamictites of the Makganyene Formation. These changes in climate are gradual, which contradict the dramatic Snowball Earth event: a rapid spread of glaciated areas over low-latitudes freezing the Earth from pole-to-pole. Therefore, to explain low-latitude glaciations at sea-level, a high obliquity of the ecliptic is most likely to have occurred. This high obliquity of the ecliptic was acquired at 4.5 Ga when a giant impactor collided into the Earth to form the Moon. Above the critical value of 54° of the obliquity of the ecliptic, normal climatic zonation reverts, and glaciations will take place preferentially at low-latitudes only when favourable conditions are gathered (relative position ofthe continents and PC02 in the atmosphere).
- Full Text:
- Date Issued: 2001
- Authors: Polteau, Stéphane
- Date: 2001
- Subjects: Geology, Stratigraphic -- South Africa -- Northern Cape , Geochemistry -- South Africa -- Northern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5003 , http://hdl.handle.net/10962/d1005616 , Geology, Stratigraphic -- South Africa -- Northern Cape , Geochemistry -- South Africa -- Northern Cape
- Description: The Makganyene Formation forms the base of the Postmasburg Group in the Transvaal Supergroup of the Northern Cape Province. The Makganyene Formation has diamictite as the main rock type, but siltstone, sandstone, shale, and iron-formations are also present. A glacial origin has been proposed in the past due to the presence of dropstones, faceted and striated pebbles. Typically, the Makganyene Formation contains banded iron-formations interbedded with clastic rocks (shale, siltstone, sandstone and diamictites) at the contact with the underlying iron-formations. This transitional zone is generally overlain by massive or layered diamictites which contain poorly sorted clasts (mainly chert) within a shaly matrix. Striated pebbles have been found during field work, and dropstones have been observed in diamictites and banded iron-formations during the study. The top of the Makganyene Formation contains graded cycles interbedded with diamictites and thin layers of andesitic lavas from the Ongeluk Formation. The basal contact of the Makganyene Formation with the underlying Koegas Subgroup was described as unconformable by previous workers. However field work localised in the Rooinekke area shows a broadly conformable and interbedded contact with the underlying Koegas Subgroup. As described above, banded iron-formations are interbedded with the clastic rocks of the Makganyene Formation. Moreover, boreholes from the Sishen area display the same interbedding at the base of the Makganyene Formation. This suggests that no significant time gap is present in the whole succession between the Ghaap and Postmasburg Group. The Transvaal Supergroup in the Northern Cape displays the following succession : carbonates-BIFs-diamictites/ lava-BIFs-carbonates. The Makganyene Formation is thus at the centre of a symmetrical lithologic succession. Bulk rock compositions show that the diamictites have a similar composition to banded iron-formation with regard to their major element contents. Banded iron-formations acted as a source for the diamictites with carbonates and igneous rocks representing minor components. Differences in bulk composition between the Sishen and Matsap areas emphasize that the source of the diamictite was very localised. The Chemical Index of Alteration (CIA) has been calculated, but since the source dominant rock was iron-formation, this index cannot be usefully applied to the diamictites. ACN, A-CN-K, and A-CNK-FM diagrams confer a major importance in sorting processes due to the separation between the fine and coarse diamictites. The interbedded iron-formations display little clastic contamination indicating deposition in clear water conditions. However, dropstones are present in one borehole from the Matsap area, indicating that iron-formation took place under ice cover, or at least under icebergs. Stable isotope studies show that the iron-formations, interbedded towards the base of the Makganyene Formation, have similar values to the iron-formations of the Koegas Subgroup. As a result of the above observations, new correlations are proposed in this study, relating the different Transvaal Supergroup basins located on the Kaapvaal Craton. The Pretoria Group of the Transvaal Basin has no correlative in the Griqualand West Basin, and the Postmasburg Group of the Northern Cape Basin has no lateral equivalent in the Transvaal Basin. These changes have been made to overcome problems present in the current correlations between those two basins. The Makganyene Formation correlates with the Huronian glaciations which occurred between 2.4 and 2.2 Ga ago in North America. Another Precambrian glaciation is the worldwide and well-studied Neoproterozoic glaciation (640 Ma). At each of these glaciations, major banded iron-formation deposition took place with associated deposition of sedimentary manganese in post-glacial positions. The central position of the Makganyene Formation within the Transvaal Supergroup in the Northern Cape emphasizes this glacial climatic dependence of paleoproterozoic banded iron-formation and manganese deposition. However these two Precambrian glaciations are interpreted in paleomagnetic studies as having occurred near to the equator. The controversial theory of the Snowball Earth has been proposed which proposes that the Earth was entirely frozen from pole to pole. Results from field work, sedimentology, petrography and geochemistry were integrated in a proposed depositional model of the Makganyene Formation occurring at the symmetrical centre of the lithologic succession of the Transvaal Supergroup. At the beginning of the Makganyene glaciation, a regression occurred and glacial advance took place. The diamictites are mostly interpreted as being deposited from wet-based glaciers, probably tidewater glaciers, where significant slumping and debris flows occurred. Any transgression would cause a glacial retreat by rapid calving, re-establishing the chemical sedimentation of banded iron-formations. These sea-level variations are responsible for the interbedding of these different types of rocks (clastic and chemical). The end of the Makganyene glacial event is characterised by subaerial eruptions of andesitic lava of the Ongeluk Formation bringing ashes into the basin. Banded iron-formation and associated manganese accumulations are climate-dependant. Glacial events are responsible for the build up of metallic ions such as iron and manganese in solution in deep waters. A warmer climate would induce a transgression and precipitation of these metallic ions when Eh conditions are favourable. In the Transvaal Supergroup, the climatic variations from warm to cold, and cold to warm are expressed by the lithologic succession. The warm climates are represented by carbonates. Cold climates are represented by banded iron-formations and the peak in cold climate represented by the diamictites of the Makganyene Formation. These changes in climate are gradual, which contradict the dramatic Snowball Earth event: a rapid spread of glaciated areas over low-latitudes freezing the Earth from pole-to-pole. Therefore, to explain low-latitude glaciations at sea-level, a high obliquity of the ecliptic is most likely to have occurred. This high obliquity of the ecliptic was acquired at 4.5 Ga when a giant impactor collided into the Earth to form the Moon. Above the critical value of 54° of the obliquity of the ecliptic, normal climatic zonation reverts, and glaciations will take place preferentially at low-latitudes only when favourable conditions are gathered (relative position ofthe continents and PC02 in the atmosphere).
- Full Text:
- Date Issued: 2001
Superstition, atheism and reasonable faith in Acts 26: a Graeco-Roman perspective on Paul’s defence before Festus and Agrippa
- Authors: Germiquet, Edouard Ariste
- Date: 2001
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:21065 , http://hdl.handle.net/10962/6224
- Description: This thesis investigates Luke‟s presentation of Paul‟s final and climactic defence of the gospel which takes place before Festus and King Agrippa II (Ac.26). It indicates how Luke has made use of the philosophical doctrine of the mean in order to present Christianity as a reasonable and rational faith. This investigation explores how Luke creates a literary framework within which to promote Paul as reasonable and rational through the application of the topos that true piety is the mean between the two extremes of superstition and atheism. The thesis is therefore structured around three dominant sections in which the major themes of superstition, atheism and rational faith are treated independently. Each section consists of an analysis of Luke‟s choice of words and his description of the behavioural patterns of each representative group so that a consistent picture progressively emerges in support of the basic framework. At all stages of the investigation, reference is made to contemporary moral philosophers, Hellenistic Judaism and the early Christian apologists so that the language, literary settings and stereotypes used by Luke can be clearly defined. This not only clarifies the text of Acts 26 but contributes to an overall appreciation of Luke‟s literary technique. At all points in the development of the thesis, the relevance and centrality which the resurrection has for Luke is kept in mind. This not only acts as a backdrop in understanding Luke‟s depiction of the superstitious and the atheist but is crucial in grasping Luke‟s presentation of Christianity as a rational faith. The thesis is brought to a close by a discussion on Luke's intended audience and the significance of his dedication to Theophilus.
- Full Text:
- Date Issued: 2001
- Authors: Germiquet, Edouard Ariste
- Date: 2001
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:21065 , http://hdl.handle.net/10962/6224
- Description: This thesis investigates Luke‟s presentation of Paul‟s final and climactic defence of the gospel which takes place before Festus and King Agrippa II (Ac.26). It indicates how Luke has made use of the philosophical doctrine of the mean in order to present Christianity as a reasonable and rational faith. This investigation explores how Luke creates a literary framework within which to promote Paul as reasonable and rational through the application of the topos that true piety is the mean between the two extremes of superstition and atheism. The thesis is therefore structured around three dominant sections in which the major themes of superstition, atheism and rational faith are treated independently. Each section consists of an analysis of Luke‟s choice of words and his description of the behavioural patterns of each representative group so that a consistent picture progressively emerges in support of the basic framework. At all stages of the investigation, reference is made to contemporary moral philosophers, Hellenistic Judaism and the early Christian apologists so that the language, literary settings and stereotypes used by Luke can be clearly defined. This not only clarifies the text of Acts 26 but contributes to an overall appreciation of Luke‟s literary technique. At all points in the development of the thesis, the relevance and centrality which the resurrection has for Luke is kept in mind. This not only acts as a backdrop in understanding Luke‟s depiction of the superstitious and the atheist but is crucial in grasping Luke‟s presentation of Christianity as a rational faith. The thesis is brought to a close by a discussion on Luke's intended audience and the significance of his dedication to Theophilus.
- Full Text:
- Date Issued: 2001
Synthesis and characterisation of novel platinum (II) complexes potential chemotherapeutic drugs
- Authors: Datt, Michael Steven
- Date: 2001
- Subjects: Chemotherapy Platinum
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4366 , http://hdl.handle.net/10962/d1005031
- Description: The present study involves the preparation of novel mixed-ligand platinum(II) complexes in the hope of expanding the range of platinum(II) complexes that exhibit anticancer activity and which are less toxic and have a broader spectrum of activity than cisplatin and its analogues. To this end, N-(3-R-benzoyl)-N’,N’-diethylthiourea, N-(3-R-benzoyl)-N’-morpholinothiourea, N-(3-Rbenzoyl)-N’,N’-di(2-hydroxyethyl)thiourea (R = NO2, Cl, H, CH3, OCH3), N,N-diethyl-N’-menthyloxycarbonylthiourea and N-menthyloxycarbonyl-N’-morpholinothiourea ligands, and their corresponding mixed-ligand platinum(II) complexes of the type [PtCl(L)(RR’SO)], were synthesised and characterised by elemental analyses, IR, 1H and 195Pt NMR spectroscopy and, in some cases, X-ray crystallography. Dimethylsulfoxide complexes were prepared using all the ligands, while complexes containing unsymmetrically substituted sulfoxides were prepared using the N-benzoyl-N’,N’-diethylthiourea and ,N-diethyl-’-(-)-(3R)-menthyloxycarbonylthiourea ligands only. The molecular structures of cis-(S,S)-[PtCl(DMSO)(L)] (where L = N-benzoyl-N’,N’-diethylthioureato, N-(+)-(3S)-menthyloxycarbonyl-N’-morpholinothioureato), cis-(S,S)-[Pt(N-benzoyl-N’,N’-diethylthioureato)Cl(MPSO)] and cis-[Pt(N-benzoyl-N’,N’-diethylthioureato)2] were determined by X-ray crystallography. The X-ray crystal structure of N,N-diethyl-N’- (-)-(3R)-menthyloxycarbonylthiourea was also determined. The spectroscopic and crystallographic data are consistent with complexes containing a (S,O)-chelated ligand and a sulfur-bonded sulfoxide ligand. However, the 1H and 195Pt NMR studies showed that the alkoxycarbonylthioureato complexes exist as geometric isomers with the sulfoxide coordinated either in a cis-(S,S) or trans-(S,S) arrangement with respect to the sulfur donor atom of the chelated ligand, whereas the acylthioureato complexes yielded only cis-(S,S)-[PtCl(L)(RR’SO)] complexes. The difference in the coordination chemistry of the acylthiourea and alkoxycarbonylthiourea ligands was examined further by treatment of the [PtCl(DMSO)(L)] complexes, where L = Nbenzoyl-N’,N’-diethylthioureato, N-benzoyl-N’-morpholinothioureato, N,N-diethyl-N’-(-)-(3R)- menthyloxycarbonylthioureato and N-(+)-(3S)-menthyloxycarbonyl-N’-morpholinothioureato, with PPh3 to give the corresponding [PtCl(L)(PPh3)] and [Pt(L)(PPh3)2]+ complexes. 31P NMR studies of these complexes reveal that the alkoxycarbonylthioureato ligands bind less strongly than the acylthioureato ligands, which is consistent with the crystallographic studies. The morpholine derivatives of the acylthioureato and alkoxycarbonylthioureato ligand systems also appear to bind less tightly than the diethyl derivatives. The weaker binding properties of the alkoxycarbonylthioureato ligands might be a possible explanation for the observed geometric isomerisation of these complexes, with the mechanism of isomerisation involving a chelate ringiv opening step. Furthermore, crystallographic and 31P NMR studies suggest that the acylthioureato carbonyl oxygen donor atom is relatively softer and therefore has a greater trans-influence than the carbonyl oxygen donor atom of the alkoxycarbonylthioureato ligand. The substitution kinetics of the chloride and sulfoxide leaving groups by azide, iodide, thiocyanate, triphenylphosphine, 2-mercaptobenzimidazole, 4-(dimethylamino)pyridine and thiourea, from selected cis-(S,S)-[PtCl(N,N-dialkyl-N’-(3-R-benzoyl)thioureato)(RR’SO)] complexes, in methanol, were evaluated to determine if variation of the electronic properties of the chelated ligand and variation of the sulfoxide have a significant influence on the reactivity of these complexes. Two consecutive reactions were observed. It was found that neutral nucleophiles initially substitute the dimethylsulfoxide, while anionic nucleophiles substituted the chloride ligand. For all the nucleophiles studied, the first substitution step was evaluated, except for triphenylphosphine and 4-(dimethylamino)pyridine, where the second step was also evaluated. The overall order of reactivity for the first substitution step was; N3 - < DMAP < I- < SCN- < MBI < thiourea < PPh3, with the rate varying three orders of magnitude. The substitution of the dimethylsulfoxide ligand by PPh3 from cis-(S,S)-[Pt(N-benzoyl-N’,N’-diethylthioureato)Cl-(DMSO)] to form cis-(S,P)-[Pt(N-benzoyl-N’,N’-diethylthioureato)Cl(PPh3)] was confirmed by X-ray crystallography. In general, manipulation of the chelating moiety, as well as interchanging the sulfoxide did not alter the reactivity of these complexes to a great extent. The anticancer activity of all the platinum(II) sulfoxide complexes were evaluated against a HeLa cell line, of which three complexes, cis-(S,S)-[PtCl(DMSO)(N,N-diethyl-N’-(3-nitrobenzoyl)- thioureato)], cis-(S,S)-[PtCl(DMSO)(N-morpholino-N’-(3-nitrorobenzoyl)thioureato)] and cis-(S,S)-[PtCl(DMSO)(N-(3-methoxybenzoyl)-N’-morpholinothioureato)] exhibited a concentration dependent anti-proliferative effect, but were less potent than cisplatin. These three complexes displayed a similar dose response in a MCF-7 cell line. Preliminary morphology studies with the three biologically active complexes in a HeLa cell line suggest that they induce cell death by apoptosis. Preliminary pBR322 plasmid DNA binding studies of selected [Pt(acylthioureato)Cl(RR’SO)]complexes clearly indicate that these complexes have a different mode of binding to DNA than cisplatin.
- Full Text:
- Date Issued: 2001
- Authors: Datt, Michael Steven
- Date: 2001
- Subjects: Chemotherapy Platinum
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4366 , http://hdl.handle.net/10962/d1005031
- Description: The present study involves the preparation of novel mixed-ligand platinum(II) complexes in the hope of expanding the range of platinum(II) complexes that exhibit anticancer activity and which are less toxic and have a broader spectrum of activity than cisplatin and its analogues. To this end, N-(3-R-benzoyl)-N’,N’-diethylthiourea, N-(3-R-benzoyl)-N’-morpholinothiourea, N-(3-Rbenzoyl)-N’,N’-di(2-hydroxyethyl)thiourea (R = NO2, Cl, H, CH3, OCH3), N,N-diethyl-N’-menthyloxycarbonylthiourea and N-menthyloxycarbonyl-N’-morpholinothiourea ligands, and their corresponding mixed-ligand platinum(II) complexes of the type [PtCl(L)(RR’SO)], were synthesised and characterised by elemental analyses, IR, 1H and 195Pt NMR spectroscopy and, in some cases, X-ray crystallography. Dimethylsulfoxide complexes were prepared using all the ligands, while complexes containing unsymmetrically substituted sulfoxides were prepared using the N-benzoyl-N’,N’-diethylthiourea and ,N-diethyl-’-(-)-(3R)-menthyloxycarbonylthiourea ligands only. The molecular structures of cis-(S,S)-[PtCl(DMSO)(L)] (where L = N-benzoyl-N’,N’-diethylthioureato, N-(+)-(3S)-menthyloxycarbonyl-N’-morpholinothioureato), cis-(S,S)-[Pt(N-benzoyl-N’,N’-diethylthioureato)Cl(MPSO)] and cis-[Pt(N-benzoyl-N’,N’-diethylthioureato)2] were determined by X-ray crystallography. The X-ray crystal structure of N,N-diethyl-N’- (-)-(3R)-menthyloxycarbonylthiourea was also determined. The spectroscopic and crystallographic data are consistent with complexes containing a (S,O)-chelated ligand and a sulfur-bonded sulfoxide ligand. However, the 1H and 195Pt NMR studies showed that the alkoxycarbonylthioureato complexes exist as geometric isomers with the sulfoxide coordinated either in a cis-(S,S) or trans-(S,S) arrangement with respect to the sulfur donor atom of the chelated ligand, whereas the acylthioureato complexes yielded only cis-(S,S)-[PtCl(L)(RR’SO)] complexes. The difference in the coordination chemistry of the acylthiourea and alkoxycarbonylthiourea ligands was examined further by treatment of the [PtCl(DMSO)(L)] complexes, where L = Nbenzoyl-N’,N’-diethylthioureato, N-benzoyl-N’-morpholinothioureato, N,N-diethyl-N’-(-)-(3R)- menthyloxycarbonylthioureato and N-(+)-(3S)-menthyloxycarbonyl-N’-morpholinothioureato, with PPh3 to give the corresponding [PtCl(L)(PPh3)] and [Pt(L)(PPh3)2]+ complexes. 31P NMR studies of these complexes reveal that the alkoxycarbonylthioureato ligands bind less strongly than the acylthioureato ligands, which is consistent with the crystallographic studies. The morpholine derivatives of the acylthioureato and alkoxycarbonylthioureato ligand systems also appear to bind less tightly than the diethyl derivatives. The weaker binding properties of the alkoxycarbonylthioureato ligands might be a possible explanation for the observed geometric isomerisation of these complexes, with the mechanism of isomerisation involving a chelate ringiv opening step. Furthermore, crystallographic and 31P NMR studies suggest that the acylthioureato carbonyl oxygen donor atom is relatively softer and therefore has a greater trans-influence than the carbonyl oxygen donor atom of the alkoxycarbonylthioureato ligand. The substitution kinetics of the chloride and sulfoxide leaving groups by azide, iodide, thiocyanate, triphenylphosphine, 2-mercaptobenzimidazole, 4-(dimethylamino)pyridine and thiourea, from selected cis-(S,S)-[PtCl(N,N-dialkyl-N’-(3-R-benzoyl)thioureato)(RR’SO)] complexes, in methanol, were evaluated to determine if variation of the electronic properties of the chelated ligand and variation of the sulfoxide have a significant influence on the reactivity of these complexes. Two consecutive reactions were observed. It was found that neutral nucleophiles initially substitute the dimethylsulfoxide, while anionic nucleophiles substituted the chloride ligand. For all the nucleophiles studied, the first substitution step was evaluated, except for triphenylphosphine and 4-(dimethylamino)pyridine, where the second step was also evaluated. The overall order of reactivity for the first substitution step was; N3 - < DMAP < I- < SCN- < MBI < thiourea < PPh3, with the rate varying three orders of magnitude. The substitution of the dimethylsulfoxide ligand by PPh3 from cis-(S,S)-[Pt(N-benzoyl-N’,N’-diethylthioureato)Cl-(DMSO)] to form cis-(S,P)-[Pt(N-benzoyl-N’,N’-diethylthioureato)Cl(PPh3)] was confirmed by X-ray crystallography. In general, manipulation of the chelating moiety, as well as interchanging the sulfoxide did not alter the reactivity of these complexes to a great extent. The anticancer activity of all the platinum(II) sulfoxide complexes were evaluated against a HeLa cell line, of which three complexes, cis-(S,S)-[PtCl(DMSO)(N,N-diethyl-N’-(3-nitrobenzoyl)- thioureato)], cis-(S,S)-[PtCl(DMSO)(N-morpholino-N’-(3-nitrorobenzoyl)thioureato)] and cis-(S,S)-[PtCl(DMSO)(N-(3-methoxybenzoyl)-N’-morpholinothioureato)] exhibited a concentration dependent anti-proliferative effect, but were less potent than cisplatin. These three complexes displayed a similar dose response in a MCF-7 cell line. Preliminary morphology studies with the three biologically active complexes in a HeLa cell line suggest that they induce cell death by apoptosis. Preliminary pBR322 plasmid DNA binding studies of selected [Pt(acylthioureato)Cl(RR’SO)]complexes clearly indicate that these complexes have a different mode of binding to DNA than cisplatin.
- Full Text:
- Date Issued: 2001
Talking about teams within a team building context: a discourse analytic study
- Authors: Chapman-Blair, Sharon
- Date: 2001
- Subjects: Discourse analysis , Teams in the workplace
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2947 , http://hdl.handle.net/10962/d1002456 , Discourse analysis , Teams in the workplace
- Description: This research initiative responds to some of the issues raised by theoretical challenges leveled at Industrial Psychology (postmodernism), and practical challenges in the workplace (the use of teams) by investigating notions of what a team is via the postmodern methodology of discourse analysis. The research explores “team talk” – repertoires of speech employed by individuals to construct particular versions of “the team” for specific effects, of importance given emphasis placed on shared understanding, expectations and goals in a “team”. A Rhodes University Industrial Psychology Honours class required to work as a team (having participated in a team building exercise), as well as their lecturers who facilitated the team building process were interviewed to obtain “talk” to analyse. This uncovered a multiplicity of meaning, namely four ways of speaking about (constructing) the team. These repertoires are explored in terms of how they are constructed, how they differ across context and speakers, how they interrelate and what they function to achieve. The educational team repertoire constructs academic hierarchy, justifies individualism, positions members as experts and maintains distance from interpersonal processes. The machine repertoire divides work and interpersonal issues, regulates productivity and constructs team roles (defining individual activity and “team fit”), but is inflexible to change. The family repertoire voices emotive aspects to maintain cohesion via conformity, leaderlessness, group identity and shared achievement, but cannot accommodate conflict or workpersonal boundaries. The psychologised team repertoire constructs the team primarily as a therapeutic entity legitimately creating individual identities (and expertise) and facilitating personal growth, but this flounders when support in the “team” fails. Given that each repertoire has a different emphasis (reflective learning versus work processes versus building relationships versus personal growth), there are slippages / clashes between repertoires. This postmodern look at “the team” thus assists in recognizing and problematising these multiple meanings and identifying practical implications.
- Full Text:
- Date Issued: 2001
- Authors: Chapman-Blair, Sharon
- Date: 2001
- Subjects: Discourse analysis , Teams in the workplace
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2947 , http://hdl.handle.net/10962/d1002456 , Discourse analysis , Teams in the workplace
- Description: This research initiative responds to some of the issues raised by theoretical challenges leveled at Industrial Psychology (postmodernism), and practical challenges in the workplace (the use of teams) by investigating notions of what a team is via the postmodern methodology of discourse analysis. The research explores “team talk” – repertoires of speech employed by individuals to construct particular versions of “the team” for specific effects, of importance given emphasis placed on shared understanding, expectations and goals in a “team”. A Rhodes University Industrial Psychology Honours class required to work as a team (having participated in a team building exercise), as well as their lecturers who facilitated the team building process were interviewed to obtain “talk” to analyse. This uncovered a multiplicity of meaning, namely four ways of speaking about (constructing) the team. These repertoires are explored in terms of how they are constructed, how they differ across context and speakers, how they interrelate and what they function to achieve. The educational team repertoire constructs academic hierarchy, justifies individualism, positions members as experts and maintains distance from interpersonal processes. The machine repertoire divides work and interpersonal issues, regulates productivity and constructs team roles (defining individual activity and “team fit”), but is inflexible to change. The family repertoire voices emotive aspects to maintain cohesion via conformity, leaderlessness, group identity and shared achievement, but cannot accommodate conflict or workpersonal boundaries. The psychologised team repertoire constructs the team primarily as a therapeutic entity legitimately creating individual identities (and expertise) and facilitating personal growth, but this flounders when support in the “team” fails. Given that each repertoire has a different emphasis (reflective learning versus work processes versus building relationships versus personal growth), there are slippages / clashes between repertoires. This postmodern look at “the team” thus assists in recognizing and problematising these multiple meanings and identifying practical implications.
- Full Text:
- Date Issued: 2001
The changing knowledge and expectations of public health nurses in a HIV/AIDS training programme for managers
- Authors: Harry, Karuna
- Date: 2001
- Subjects: HIV infections , HIV infections -- Nursing , HIV-positive persons -- Counseling of
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2986 , http://hdl.handle.net/10962/d1002495 , HIV infections , HIV infections -- Nursing , HIV-positive persons -- Counseling of
- Description: This research project examined the changing expectations and knowledge of Managers in the Department of Health who attended the Sexual Health Counselling Project offered by Rhodes University, East London, South Africa. These managers came from contexts in which the hierarchical medical model is firmly entrenched. The Sexual Health Counselling Project, drawing on theoretical principles from Narrative and other theories,presented a challenge to the standard management practices used by the managers. It also challenged how they dealt with clients. This research explored changes in expectations and knowledge prior to and during a two- week training course that the managers attended. A personal awareness and shift in knowledge occurred for many managers who examined their current practices. Some managers, who were firmly entrenched in the hierarchical model,found it difficult to change their ways of working.
- Full Text:
- Date Issued: 2001
- Authors: Harry, Karuna
- Date: 2001
- Subjects: HIV infections , HIV infections -- Nursing , HIV-positive persons -- Counseling of
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2986 , http://hdl.handle.net/10962/d1002495 , HIV infections , HIV infections -- Nursing , HIV-positive persons -- Counseling of
- Description: This research project examined the changing expectations and knowledge of Managers in the Department of Health who attended the Sexual Health Counselling Project offered by Rhodes University, East London, South Africa. These managers came from contexts in which the hierarchical medical model is firmly entrenched. The Sexual Health Counselling Project, drawing on theoretical principles from Narrative and other theories,presented a challenge to the standard management practices used by the managers. It also challenged how they dealt with clients. This research explored changes in expectations and knowledge prior to and during a two- week training course that the managers attended. A personal awareness and shift in knowledge occurred for many managers who examined their current practices. Some managers, who were firmly entrenched in the hierarchical model,found it difficult to change their ways of working.
- Full Text:
- Date Issued: 2001
The construction of 'farm killings' in the Eastern Province Herald: an ideological analysis of the Herald's farm killings' disclosure, August 1998
- Authors: Jacobs, Luzuko
- Date: 2001
- Subjects: Farm killings -- South Africa -- Eastern Cape Murder -- South Africa -- Eastern Cape Eastern Province Herald (Newspaper)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3436 , http://hdl.handle.net/10962/d1002890
- Description: This study examines the ideological inflection of the ‘farm killings’ discourse in the Eastern Province Herald articles published in August 1998. ‘Farm killings’ is a media frame which was applied to a spate of killings of people on the country’s farms since 1994. Heightened and sustained media attention on the ‘farm killings’ has lifted the phenomenon from the other ‘run-of-the-mill’ murder crimes, and located it firmly as a matter of public concern and a subject of a broad political and economic debate. In this study I investigate the media coverage of the ‘farm killings’ within the context of these debates. The cultural studies approach to the study of the media provides a fruitful theoretical framework within which this study is located. The ideological examination of the articles is done using the critical linguistics method - a brand of reflexive, interpretative style of analysis which enables a sustained examination of media texts within their social, cultural and historical context. This study’s conclusions pose a challenge to the ‘Fourth Estate’ role often claimed for the media. In particular, it denies that the Herald objectively, fairly and truthfully reflected the experience on the farms during the period of this study. Its main finding is that the newspaper instead, constructed a particular understanding of the killings characterised by subtle racism, bias and partiality.
- Full Text:
- Date Issued: 2001
- Authors: Jacobs, Luzuko
- Date: 2001
- Subjects: Farm killings -- South Africa -- Eastern Cape Murder -- South Africa -- Eastern Cape Eastern Province Herald (Newspaper)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3436 , http://hdl.handle.net/10962/d1002890
- Description: This study examines the ideological inflection of the ‘farm killings’ discourse in the Eastern Province Herald articles published in August 1998. ‘Farm killings’ is a media frame which was applied to a spate of killings of people on the country’s farms since 1994. Heightened and sustained media attention on the ‘farm killings’ has lifted the phenomenon from the other ‘run-of-the-mill’ murder crimes, and located it firmly as a matter of public concern and a subject of a broad political and economic debate. In this study I investigate the media coverage of the ‘farm killings’ within the context of these debates. The cultural studies approach to the study of the media provides a fruitful theoretical framework within which this study is located. The ideological examination of the articles is done using the critical linguistics method - a brand of reflexive, interpretative style of analysis which enables a sustained examination of media texts within their social, cultural and historical context. This study’s conclusions pose a challenge to the ‘Fourth Estate’ role often claimed for the media. In particular, it denies that the Herald objectively, fairly and truthfully reflected the experience on the farms during the period of this study. Its main finding is that the newspaper instead, constructed a particular understanding of the killings characterised by subtle racism, bias and partiality.
- Full Text:
- Date Issued: 2001
The determination of geomorphologically effective flows for selected eastern sea-Board Rivers in South Africa
- Authors: Dollar, Evan S J
- Date: 2001
- Subjects: Rivers--South Africa River channels Geomorphology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4824 , http://hdl.handle.net/10962/d1005499
- Description: In South Africa the need to protect and manage the national water resource has led to the development of the Reserve as a basic right under the National Water Act (1998). The Ecological Reserve relates to the quality and quantity of water necessary to protect the sustainable functioning of aquatic ecosystems. The geomorphological contribution to setting the Reserve has focussed on three groups of information requirements: the spatial and temporal availability of habitat, the maintenance of substratum characteristics, and the maintenance of channel form. This thesis focusses on the second and third information requirements. The thesis has attempted to achieve this by adding value to the theoretical and applied understanding of the magnitude and frequency of channel forming discharge for selected southern African rivers. Many of the eastern sea-board rivers are strongly influenced by bed rock in the channel perimeter, and by a highly variable hydrological regime. This has resulted in characteristic channel forms, with an active channel incised into a larger macro-channel being a common feature of eastern seaboard rivers. Within the active channel inset channel benches commonly occur. This alluvial architecture is used to provide clues as to the types of flows necessary to meet the Reserve. Three river basins are considered : the Mkomazi, Mhlathuze and Olifants. The Mkomazi is a relatively un-impacted perennial eastern-sea board river and forms the research component of the study. The Mhlathuze and Olifants rivers are highly regulated systems and form the application component of the study. Utilising synthesised daily hydrological data, bed material data, cross-sectional surveys, hydraulic data and relevant bed material transport equations, channel form was related to dominant discharge and effective discharge in an attempt to identify the magnitude and frequency offlows that can be considered to be ' effective'. Results from the Mkomazi River indicate that no single effective discharge exists, but rather that there is a range of effective discharges in the 5-0.1% range on the 1-day daily flow duration curves that are responsible for the bulk (>80%) of the bed material transport. Only large floods (termed 'reset'discharges) with average return periods of around 20 years generate sufficient stream power and shear stress to mobilise the entire bed. The macro-channel is thus maintained by the large ' reset' flood events, and the active channel is maintained both by the range of effective discharges and the ' reset 'discharges. These are the geomorphologically 'effective' flows. Results from the Mhlathuze River have indicated that the Goedertrouw Dam has had a considerable impact on the downstream channel morphology and bed material transport capacity and consequently the effective and dominant discharges. It has been suggested that the Mhlathuze River is now adjusting its channel geometry in sympathy with the regulated flow environment. Under present-day conditions it has been demonstrated that the total bed material load has been reduced by up to three times, but there has also been a clear change in the way in which the load has been distributed around the duration curve. Under present-day conditions, over 90% of the total bed material load is transported by the top 5% of the flows, whereas under virgin flow conditions 90% of the total bed material load was transported by the top 20% of the flows. For the Olifants River there appears to be no relationship between the estimated bankfull discharge and any hydrological statistic. The effective discharge flow class is in the 5-0.01% range on the 1-day daily flow duration curve. It has also been pointed out that even the highest flows simulated for the Olifants River do not generate sufficient energy to mobilise the entire bed. It is useful to consider the Olifants River as being adapted to a highly variable flow regime. It is erroneous to think of one ' effective' discharge, but rather a range of effective discharges are of significance. It has been argued that strong bed rock control and a highly variable flow regime in many southern African rivers accounts for the channel architecture, and that there is a need to develop an ' indigenous knowledge' in the management of southern African fluvial systems
- Full Text:
- Date Issued: 2001
- Authors: Dollar, Evan S J
- Date: 2001
- Subjects: Rivers--South Africa River channels Geomorphology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4824 , http://hdl.handle.net/10962/d1005499
- Description: In South Africa the need to protect and manage the national water resource has led to the development of the Reserve as a basic right under the National Water Act (1998). The Ecological Reserve relates to the quality and quantity of water necessary to protect the sustainable functioning of aquatic ecosystems. The geomorphological contribution to setting the Reserve has focussed on three groups of information requirements: the spatial and temporal availability of habitat, the maintenance of substratum characteristics, and the maintenance of channel form. This thesis focusses on the second and third information requirements. The thesis has attempted to achieve this by adding value to the theoretical and applied understanding of the magnitude and frequency of channel forming discharge for selected southern African rivers. Many of the eastern sea-board rivers are strongly influenced by bed rock in the channel perimeter, and by a highly variable hydrological regime. This has resulted in characteristic channel forms, with an active channel incised into a larger macro-channel being a common feature of eastern seaboard rivers. Within the active channel inset channel benches commonly occur. This alluvial architecture is used to provide clues as to the types of flows necessary to meet the Reserve. Three river basins are considered : the Mkomazi, Mhlathuze and Olifants. The Mkomazi is a relatively un-impacted perennial eastern-sea board river and forms the research component of the study. The Mhlathuze and Olifants rivers are highly regulated systems and form the application component of the study. Utilising synthesised daily hydrological data, bed material data, cross-sectional surveys, hydraulic data and relevant bed material transport equations, channel form was related to dominant discharge and effective discharge in an attempt to identify the magnitude and frequency offlows that can be considered to be ' effective'. Results from the Mkomazi River indicate that no single effective discharge exists, but rather that there is a range of effective discharges in the 5-0.1% range on the 1-day daily flow duration curves that are responsible for the bulk (>80%) of the bed material transport. Only large floods (termed 'reset'discharges) with average return periods of around 20 years generate sufficient stream power and shear stress to mobilise the entire bed. The macro-channel is thus maintained by the large ' reset' flood events, and the active channel is maintained both by the range of effective discharges and the ' reset 'discharges. These are the geomorphologically 'effective' flows. Results from the Mhlathuze River have indicated that the Goedertrouw Dam has had a considerable impact on the downstream channel morphology and bed material transport capacity and consequently the effective and dominant discharges. It has been suggested that the Mhlathuze River is now adjusting its channel geometry in sympathy with the regulated flow environment. Under present-day conditions it has been demonstrated that the total bed material load has been reduced by up to three times, but there has also been a clear change in the way in which the load has been distributed around the duration curve. Under present-day conditions, over 90% of the total bed material load is transported by the top 5% of the flows, whereas under virgin flow conditions 90% of the total bed material load was transported by the top 20% of the flows. For the Olifants River there appears to be no relationship between the estimated bankfull discharge and any hydrological statistic. The effective discharge flow class is in the 5-0.01% range on the 1-day daily flow duration curve. It has also been pointed out that even the highest flows simulated for the Olifants River do not generate sufficient energy to mobilise the entire bed. It is useful to consider the Olifants River as being adapted to a highly variable flow regime. It is erroneous to think of one ' effective' discharge, but rather a range of effective discharges are of significance. It has been argued that strong bed rock control and a highly variable flow regime in many southern African rivers accounts for the channel architecture, and that there is a need to develop an ' indigenous knowledge' in the management of southern African fluvial systems
- Full Text:
- Date Issued: 2001
The development and assessment of both a separate, once-daily modified release matrix formulation of metoprolol tartrate and a combination formulation with hydrochlorothiazide
- Authors: Arjun, Jessica
- Date: 2001
- Subjects: Metoprolol -- Controlled release , Chlorothiazide -- Controlled release , Diuretics , Hypertension -- Treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3742 , http://hdl.handle.net/10962/d1003220 , Metoprolol -- Controlled release , Chlorothiazide -- Controlled release , Diuretics , Hypertension -- Treatment
- Description: The use of controlled release dosage forms has increased significantly in recent years as they result in increased patient compliance and higher therapeutic efficiency. This research focused on the development of a once daily dosage form that could be used for the treatment of hypertension. Both a separate sustained release dosage of metoprolol tartrate and a combination dosage form that included both an immediate release hydrochlorothiazide and a sustained release metoprolol component, were developed and evaluated. A matrix tablet, consisting of an ethylcellulose ranulation of metoprolol tartrate compressed into a hydrophilic hydroxypropyl methylcellulose polymer matrix, effectively sustained metoprolol release over a 22-hour experimental period. A multiparticulate combination dosage form that consisted of six coated mini matrix tablets of metoprolol and a powder blend of hydrochlorothiazide packed into a gelatin capsule, displayed zero order release kinetics for metoprolol release over 22 hours (r2=0.9946). The release of hydrochlorothiazide was found to be comparable to that of a commercially available product tested. Differential Scanning Calorimetry was used to identify possible incompatibilities between MPTA and excipients initially, and long term stability testing was used to assess to behaviour of the dosage form. Dissolution testing of the dosage forms was performed using USP Apparatus III, which was found to be more discriminating between the batches assessed. Dissolution curves were evaluated for similarity and difference using f1 and f2 fit factors. Samples were analyzed using a high performance liquid chromatographic method that was developed and validated for the simultaneous determination of the compounds of interest. Various factors influencing drug release from the developed dosage forms were assessed and recommendations for further optimization of the formulation are made. Factors evaluated included the quantity of granulating fluid, matrix polymer content, drug load and process variables, including drying time and compression force. The influence of various coating levels on drug release was assessed and none of the levels assessed were found to adequately retarded drug release over a 22-hour period. Combinations of tablets coated to different levels allowed for the successful development of a sustained release metoprolol component, which could be included into the combination dosage form.
- Full Text:
- Date Issued: 2001
- Authors: Arjun, Jessica
- Date: 2001
- Subjects: Metoprolol -- Controlled release , Chlorothiazide -- Controlled release , Diuretics , Hypertension -- Treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3742 , http://hdl.handle.net/10962/d1003220 , Metoprolol -- Controlled release , Chlorothiazide -- Controlled release , Diuretics , Hypertension -- Treatment
- Description: The use of controlled release dosage forms has increased significantly in recent years as they result in increased patient compliance and higher therapeutic efficiency. This research focused on the development of a once daily dosage form that could be used for the treatment of hypertension. Both a separate sustained release dosage of metoprolol tartrate and a combination dosage form that included both an immediate release hydrochlorothiazide and a sustained release metoprolol component, were developed and evaluated. A matrix tablet, consisting of an ethylcellulose ranulation of metoprolol tartrate compressed into a hydrophilic hydroxypropyl methylcellulose polymer matrix, effectively sustained metoprolol release over a 22-hour experimental period. A multiparticulate combination dosage form that consisted of six coated mini matrix tablets of metoprolol and a powder blend of hydrochlorothiazide packed into a gelatin capsule, displayed zero order release kinetics for metoprolol release over 22 hours (r2=0.9946). The release of hydrochlorothiazide was found to be comparable to that of a commercially available product tested. Differential Scanning Calorimetry was used to identify possible incompatibilities between MPTA and excipients initially, and long term stability testing was used to assess to behaviour of the dosage form. Dissolution testing of the dosage forms was performed using USP Apparatus III, which was found to be more discriminating between the batches assessed. Dissolution curves were evaluated for similarity and difference using f1 and f2 fit factors. Samples were analyzed using a high performance liquid chromatographic method that was developed and validated for the simultaneous determination of the compounds of interest. Various factors influencing drug release from the developed dosage forms were assessed and recommendations for further optimization of the formulation are made. Factors evaluated included the quantity of granulating fluid, matrix polymer content, drug load and process variables, including drying time and compression force. The influence of various coating levels on drug release was assessed and none of the levels assessed were found to adequately retarded drug release over a 22-hour period. Combinations of tablets coated to different levels allowed for the successful development of a sustained release metoprolol component, which could be included into the combination dosage form.
- Full Text:
- Date Issued: 2001
The development of a scale to measure sexual orientation and an examination of its psychometric properties
- Authors: Heath, Lance Julian
- Date: 2001
- Subjects: Sexual orientation , Sexual orientation -- Research -- Psychological aspects , Psychometrics
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3145 , http://hdl.handle.net/10962/d1007408 , Sexual orientation , Sexual orientation -- Research -- Psychological aspects , Psychometrics
- Description: The purpose of the study was to develop a scale to measure sexual orientation and to examine its psychometric properties. Previous scales were critically examined and compared and the need for a scale which simultaneously measures same and opposite sex responsiveness independently, and accounts for dynamic changes over time, while testing a number of overt and covert dimensions of sexual orientations, was established. A 48-item scale was designed to tap self-reported intensity and frequency of Emotional Attachment, Sexual Fantasy, Sexual Attraction and Sexual Contact towards males and females in the Past, Present and Future. An initial study was conducted with 13 undergraduate university students of both genders, representing a variety of sexual orientations and nationalities, and qualitative feedback was obtained and utilized to make appropriate adjustments and refinements to the scale. The scale was then administered to 133 Rhodes University undergraduate psychology students to obtain quantitative data with regard to its internal structure. The scale was found to have a good internal consistency reliability Cronbach alpha coefficient of 0.8106. Existing sub-scales had lower alpha coefficients. Factor analysis, a form of construct validation, was performed and four factors emerged. These had very good internal consistency reliability alpha coefficients: Sexual Responsiveness to Females (0.9894), Sexual Responsiveness to Males (0.9741), Emotional Attachment to Females (0.8403) and Emotional Attachment to Males (0.8372). These factors were further statistically analysed to ascertain how they relate to one another and to the demographics of gender, age, relational status and sexual orientation identity. Future research will need to assess other forms of reliability and validity and focus on larger and more varied samples.
- Full Text:
- Date Issued: 2001
- Authors: Heath, Lance Julian
- Date: 2001
- Subjects: Sexual orientation , Sexual orientation -- Research -- Psychological aspects , Psychometrics
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3145 , http://hdl.handle.net/10962/d1007408 , Sexual orientation , Sexual orientation -- Research -- Psychological aspects , Psychometrics
- Description: The purpose of the study was to develop a scale to measure sexual orientation and to examine its psychometric properties. Previous scales were critically examined and compared and the need for a scale which simultaneously measures same and opposite sex responsiveness independently, and accounts for dynamic changes over time, while testing a number of overt and covert dimensions of sexual orientations, was established. A 48-item scale was designed to tap self-reported intensity and frequency of Emotional Attachment, Sexual Fantasy, Sexual Attraction and Sexual Contact towards males and females in the Past, Present and Future. An initial study was conducted with 13 undergraduate university students of both genders, representing a variety of sexual orientations and nationalities, and qualitative feedback was obtained and utilized to make appropriate adjustments and refinements to the scale. The scale was then administered to 133 Rhodes University undergraduate psychology students to obtain quantitative data with regard to its internal structure. The scale was found to have a good internal consistency reliability Cronbach alpha coefficient of 0.8106. Existing sub-scales had lower alpha coefficients. Factor analysis, a form of construct validation, was performed and four factors emerged. These had very good internal consistency reliability alpha coefficients: Sexual Responsiveness to Females (0.9894), Sexual Responsiveness to Males (0.9741), Emotional Attachment to Females (0.8403) and Emotional Attachment to Males (0.8372). These factors were further statistically analysed to ascertain how they relate to one another and to the demographics of gender, age, relational status and sexual orientation identity. Future research will need to assess other forms of reliability and validity and focus on larger and more varied samples.
- Full Text:
- Date Issued: 2001
The development of the common fraction concept in grade three learners
- Authors: Fraser, Claire Anne
- Date: 2001
- Subjects: Mathematics -- Study and teaching (Elementary) Mathematics Problems, exercises, etc Fractions -- Study and teaching (Elementary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1497 , http://hdl.handle.net/10962/d1003379
- Description: Over a period of nine months in 1999, a longitudinal teaching intervention was undertaken with Grade 3 learners in the Fort Beaufort district, Eastern Cape. Working in the interpretive paradigm, the intervention focussed on: - the development of the common fraction concept, - the relevance of the hierarchy of Murray and Olivier’s Four Levels of Development in common fractions and - whether learners’ informal knowledge could be utilised in developing this concept. Using the Problem-centred approach to teaching mathematics, problems set in reallife contexts were used as vehicles for learning. Learners were required to discuss, reflect and make sense of the mathematics they were doing. Participant observation, completed worksheets and unstructured interviews with learners, formed the primary method of data collection. Learners’ work was analysed and classified according to the method used and manner in which the solution was notated. Results showed that learners were able to achieve a significant degree of success in developing a stable common fraction concept. Learners were afforded opportunities to construct their own ideas and to develop a deeper understanding of the concept. Many methods used were based on their informal knowledge of sharing. Learners made sense of realistic problems using drawings, and invented their own procedures. Apart from Level One, Phase Three, all Murray and Olivier’s Levels of Development could be identified during the research. This study will provide educators with valuable information on how learners solve mathematical problems involving fractions and how informal knowledge can be used as a foundation on which to build.
- Full Text:
- Date Issued: 2001
- Authors: Fraser, Claire Anne
- Date: 2001
- Subjects: Mathematics -- Study and teaching (Elementary) Mathematics Problems, exercises, etc Fractions -- Study and teaching (Elementary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1497 , http://hdl.handle.net/10962/d1003379
- Description: Over a period of nine months in 1999, a longitudinal teaching intervention was undertaken with Grade 3 learners in the Fort Beaufort district, Eastern Cape. Working in the interpretive paradigm, the intervention focussed on: - the development of the common fraction concept, - the relevance of the hierarchy of Murray and Olivier’s Four Levels of Development in common fractions and - whether learners’ informal knowledge could be utilised in developing this concept. Using the Problem-centred approach to teaching mathematics, problems set in reallife contexts were used as vehicles for learning. Learners were required to discuss, reflect and make sense of the mathematics they were doing. Participant observation, completed worksheets and unstructured interviews with learners, formed the primary method of data collection. Learners’ work was analysed and classified according to the method used and manner in which the solution was notated. Results showed that learners were able to achieve a significant degree of success in developing a stable common fraction concept. Learners were afforded opportunities to construct their own ideas and to develop a deeper understanding of the concept. Many methods used were based on their informal knowledge of sharing. Learners made sense of realistic problems using drawings, and invented their own procedures. Apart from Level One, Phase Three, all Murray and Olivier’s Levels of Development could be identified during the research. This study will provide educators with valuable information on how learners solve mathematical problems involving fractions and how informal knowledge can be used as a foundation on which to build.
- Full Text:
- Date Issued: 2001
The ecology and physiology of the springhare (Pedetes capensis) in the Eastern Cape Province of South Africa
- Authors: Peinke, Dean Michael
- Date: 2001
- Subjects: Hares -- South Africa -- Eastern Cape Hares -- Breeding -- South Africa -- Eastern Cape Hares -- Ecology -- South Africa -- Eastern Cape Hares -- Physiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5670 , http://hdl.handle.net/10962/d1005355
- Description: Springhare are large, bipedal, nocturnal, herbivorous, burrowing rodents that are found in arid and semi-arid parts of southern and eastern Africa. In this thesis I examine the general ecology, biology and physiology of these animals in the Eastern Cape Province of South Africa. An investigation of their distribution and activity in the study site showed that springhare exhibit a preference for flat, open, recently disturbed habitat that is dominated by the grass Cynodon dactylon and the sedge Cyperus esculentus. These two species constitute a major proportion of their diet. The impact of spring hare on chicory and grazing is also discussed. Nightly activity generally peaks soon after dark and decreases in the 2-4 hour period before sunrise. This pattern is, however, modified by moonlight. Springhare typically respond to moonlight by reducing aboveground activity, shifting their activity to dark moonless periods of the night, and by reducing their use of open space. Contrary to earlier reports, springhare utilise several different burrow systems spread over large areas. They regularly change burrow systems and seldom spend more than a few consecutive days in each. Springhare do not appear to defend territories but recently used burrows appear to be avoided by conspecifics. Males and females on average use a similar number of burrows, scattered over similar sized areas. Burrows are shown to provide a stable microclimate of moderate temperature and high humidity throughout the year. Reproduction is continuous and there is no synchronised breeding season. The ability to reproduce throughout the year is attributed primarily to their ability to utilise subterranean food stores. The overall reproductive strategy of springhare (a single young with long gestation and weaning) is unusual for a mammal of this size but may be linked to low levels of adult and juvenile mortality. Physiologically, springhare are reasonably well adapted to life in hot, arid environments. They produce a concentrated urine, exhibit a high tolerance to dehydration, are good osmoregulators capable of maintaining plasma volume, osmolality and ion balance over long periods of water deprivation, and are able to produce dry faeces. They are also good thermoregulators at low ambient temperatures, which are usually encountered at night, but are poor thermoregulators at high ambient temperatures, which they avoid behaviourally.
- Full Text:
- Date Issued: 2001
- Authors: Peinke, Dean Michael
- Date: 2001
- Subjects: Hares -- South Africa -- Eastern Cape Hares -- Breeding -- South Africa -- Eastern Cape Hares -- Ecology -- South Africa -- Eastern Cape Hares -- Physiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5670 , http://hdl.handle.net/10962/d1005355
- Description: Springhare are large, bipedal, nocturnal, herbivorous, burrowing rodents that are found in arid and semi-arid parts of southern and eastern Africa. In this thesis I examine the general ecology, biology and physiology of these animals in the Eastern Cape Province of South Africa. An investigation of their distribution and activity in the study site showed that springhare exhibit a preference for flat, open, recently disturbed habitat that is dominated by the grass Cynodon dactylon and the sedge Cyperus esculentus. These two species constitute a major proportion of their diet. The impact of spring hare on chicory and grazing is also discussed. Nightly activity generally peaks soon after dark and decreases in the 2-4 hour period before sunrise. This pattern is, however, modified by moonlight. Springhare typically respond to moonlight by reducing aboveground activity, shifting their activity to dark moonless periods of the night, and by reducing their use of open space. Contrary to earlier reports, springhare utilise several different burrow systems spread over large areas. They regularly change burrow systems and seldom spend more than a few consecutive days in each. Springhare do not appear to defend territories but recently used burrows appear to be avoided by conspecifics. Males and females on average use a similar number of burrows, scattered over similar sized areas. Burrows are shown to provide a stable microclimate of moderate temperature and high humidity throughout the year. Reproduction is continuous and there is no synchronised breeding season. The ability to reproduce throughout the year is attributed primarily to their ability to utilise subterranean food stores. The overall reproductive strategy of springhare (a single young with long gestation and weaning) is unusual for a mammal of this size but may be linked to low levels of adult and juvenile mortality. Physiologically, springhare are reasonably well adapted to life in hot, arid environments. They produce a concentrated urine, exhibit a high tolerance to dehydration, are good osmoregulators capable of maintaining plasma volume, osmolality and ion balance over long periods of water deprivation, and are able to produce dry faeces. They are also good thermoregulators at low ambient temperatures, which are usually encountered at night, but are poor thermoregulators at high ambient temperatures, which they avoid behaviourally.
- Full Text:
- Date Issued: 2001
The effect of photoperiod on some aspects of reproduction in a Southern African rodent : the pouched mouse (Saccostomus Campestris)
- Authors: Gray, Janine
- Date: 2001
- Subjects: Mice -- Reproduction Antechinus -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5676 , http://hdl.handle.net/10962/d1005361
- Description: The pouched mouse, Saccostomus campestris is widely distributed south of the Sahara, inhabiting both subtropical and tropical latitudes and a number of different biotic zones, where it breeds seasonally. In North temperate latitudes, reproduction in small mammals is controlled by photoperiod however this cue becomes less influential as latitude decreases towards the equator. The aim of the present study is to establish the role of photoperiod in the environmental control of reproduction in a seasonally breeding small mammal at low latitudes in a highly unpredictable environment. Spermatogenesis of domesticated and Fl-generation pouched mice was not inhibited by short daylength while decreasing daylength significantly affected the oestrous cycle of adult domesticated female pouched mice. Photoperiod had little effect on the oestrous cycle of F I-generation females while a possible inherent circannual endogenous rhythm controlled inhibition of reproduction in these females. Body mass of male and female juvenile pouched mice was consistently lower in short daylength and in juvenile female pouched mice the onset of fertility may be weight-dependent. The attainment of sexual maturity of domesticated and FIlF2-generation females was retarded but not halted in short daylength and females in long daylength reached puberty 7.8 - 10.2 days earlier. Short daylength also lengthened the interval between vaginal perforation and first oestrus. Puberty in juvenile females was age-dependent as both domesticated and FIlF2-generation males attained puberty at 50 days of age, although fewer males were fertile in long daylength than short daylength. Although litter size of pouched mice was smaller in short daylength for both domesticated and wildcaught females this was not due to a reduction in the ovulation rate. Domesticated females had significantly larger litters than wild-caught females. Male and female pouched mice have evolved different reproductive strategies as males become sexually mature at the same age irrespective of photoperiod and remain fertile throughout the year. In contrast, females tend to be more complex as juveniles delay reproductive maturity and adults become nonreproductive in short daylength. However, in the presence of a fertile male and if environmental conditions are favourable, in short daylength, females can become reproductively active within approximately 3 days. Thus, although the pouched mouse has adopted a purely opportunistic reproductive strategy, vestiges of photoresponsiveness are still present in the female. The seasonality exhibited in the wild is therefore due to the female. Pouched mice live in a highly unpredictable environment so the sole use of photoperiod to regulate reproduction would be disadvantageous.
- Full Text:
- Date Issued: 2001
- Authors: Gray, Janine
- Date: 2001
- Subjects: Mice -- Reproduction Antechinus -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5676 , http://hdl.handle.net/10962/d1005361
- Description: The pouched mouse, Saccostomus campestris is widely distributed south of the Sahara, inhabiting both subtropical and tropical latitudes and a number of different biotic zones, where it breeds seasonally. In North temperate latitudes, reproduction in small mammals is controlled by photoperiod however this cue becomes less influential as latitude decreases towards the equator. The aim of the present study is to establish the role of photoperiod in the environmental control of reproduction in a seasonally breeding small mammal at low latitudes in a highly unpredictable environment. Spermatogenesis of domesticated and Fl-generation pouched mice was not inhibited by short daylength while decreasing daylength significantly affected the oestrous cycle of adult domesticated female pouched mice. Photoperiod had little effect on the oestrous cycle of F I-generation females while a possible inherent circannual endogenous rhythm controlled inhibition of reproduction in these females. Body mass of male and female juvenile pouched mice was consistently lower in short daylength and in juvenile female pouched mice the onset of fertility may be weight-dependent. The attainment of sexual maturity of domesticated and FIlF2-generation females was retarded but not halted in short daylength and females in long daylength reached puberty 7.8 - 10.2 days earlier. Short daylength also lengthened the interval between vaginal perforation and first oestrus. Puberty in juvenile females was age-dependent as both domesticated and FIlF2-generation males attained puberty at 50 days of age, although fewer males were fertile in long daylength than short daylength. Although litter size of pouched mice was smaller in short daylength for both domesticated and wildcaught females this was not due to a reduction in the ovulation rate. Domesticated females had significantly larger litters than wild-caught females. Male and female pouched mice have evolved different reproductive strategies as males become sexually mature at the same age irrespective of photoperiod and remain fertile throughout the year. In contrast, females tend to be more complex as juveniles delay reproductive maturity and adults become nonreproductive in short daylength. However, in the presence of a fertile male and if environmental conditions are favourable, in short daylength, females can become reproductively active within approximately 3 days. Thus, although the pouched mouse has adopted a purely opportunistic reproductive strategy, vestiges of photoresponsiveness are still present in the female. The seasonality exhibited in the wild is therefore due to the female. Pouched mice live in a highly unpredictable environment so the sole use of photoperiod to regulate reproduction would be disadvantageous.
- Full Text:
- Date Issued: 2001
The effects of level and quality of education on a South African sample of English and African first language speakers, for WAIS-III digit symbol-incidental learning
- Donnelly, Martin Joseph Rhodes
- Authors: Donnelly, Martin Joseph Rhodes
- Date: 2001
- Subjects: Wechsler Adult Intelligence Scale , Intelligence tests -- South Africa , Wechsler Adult Intelligence Scale -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2965 , http://hdl.handle.net/10962/d1002474 , Wechsler Adult Intelligence Scale , Intelligence tests -- South Africa , Wechsler Adult Intelligence Scale -- South Africa
- Description: This study examined the effects of level and quality of education on WAIS-III Digit Symbol-Incidental Learning performance. The Pairing and Free Recall measures were administered to a South African sample (N = 68, age range 19-30), which was stratified for English and African language, level of education attained (Grade 12s and Graduates) and quality of education (advantaged and disadvantaged schooling). Results yielded no significant main or interaction effects between acculturation factors of level and quality of education. Normative guidelines of 13 or more pairs and 8 or more free recall symbols, appropriate to a non-clinical sample in a multicultural setting, are provided. Digit Symbol-Incidental Learning proved to be a culture-fair test, which contributes to its clinical utility as a sensitive memory screening tool.
- Full Text:
- Date Issued: 2001
- Authors: Donnelly, Martin Joseph Rhodes
- Date: 2001
- Subjects: Wechsler Adult Intelligence Scale , Intelligence tests -- South Africa , Wechsler Adult Intelligence Scale -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2965 , http://hdl.handle.net/10962/d1002474 , Wechsler Adult Intelligence Scale , Intelligence tests -- South Africa , Wechsler Adult Intelligence Scale -- South Africa
- Description: This study examined the effects of level and quality of education on WAIS-III Digit Symbol-Incidental Learning performance. The Pairing and Free Recall measures were administered to a South African sample (N = 68, age range 19-30), which was stratified for English and African language, level of education attained (Grade 12s and Graduates) and quality of education (advantaged and disadvantaged schooling). Results yielded no significant main or interaction effects between acculturation factors of level and quality of education. Normative guidelines of 13 or more pairs and 8 or more free recall symbols, appropriate to a non-clinical sample in a multicultural setting, are provided. Digit Symbol-Incidental Learning proved to be a culture-fair test, which contributes to its clinical utility as a sensitive memory screening tool.
- Full Text:
- Date Issued: 2001
The effects of melatonin on the testis, epididymis and sperm physiology of the Wistar rat
- Authors: Gwayi, Noluzuko
- Date: 2001
- Subjects: Rats as laboratory animals , Rats -- physiology , Spermatozoa , Melatonin , Testis , Epididymis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5681 , http://hdl.handle.net/10962/d1005366 , Rats as laboratory animals , Rats -- physiology , Spermatozoa , Melatonin , Testis , Epididymis
- Description: Melatonin is a product of the pineal gland and is postulated to play an antigonadotropic role in the reproductive system of mammals. The reproductive system of non-seasonally breeding mammals is believed to be not as responsive to melatonin treatment as that of seasonally breeding mammals. Recently, there has been increasing support from in vivo and in vitro studies, for the hypothesis that melatonin has negative effects on sperm physiology, especially on sperm motility. High and/or low seminal concentrations of melatonin have been associated with abnormalities in human sperm motility and concentration. In this study, I examined the effects of melatonin on the testis, epididymis and sperm physiology, using in vivo and in vitro experiments, in a non-seasonally breeding mammal. Treatment, in vivo, with exogenous melatonin for six weeks did not inhibit testosterone production or spermatogenesis, nor did it affect the mass of the testes and epididymides at dissection, the concentration the morphology of speimatozoa. However, melatonin in vivo had a small, but significant negative effect on sperm motility and sperm motility index. In vitro incubation of spermatozoa Fith melatonin reduced the percentage (%) of forward progressive movement (fpm), increased the % reduction in fpm, reduced the vigor or quality of sperm motility, reduced the sperm motility index, and delayed and/or prolonged the transition of one pattern of sperm motility to the subsequent patterns. Melatonin increased the pH of the culture medium, and the increased pH, and the ethanol utilized as a solvent for melatonin, both negatively affected all the sperm motility parameters that were assessed in my study. The effects of ethanol increased with time, and the effects of pH increased with both time and increasing pH. Melatonin in vitro did not inhibit capacitation and the acrosome reaction, but it delayed the onset and the progression of capacitation and the acrosome reaction. These results suggest that while melatonin did not inhibit spermatogenesis in the Wistar rat, it may influence sperm motility. Therefore, the presence of high concentrations of melatonin in the reproductive fluids may inhibit sperm motility. With further detailed research, melatonin may have a potential use as a contraceptive drug.
- Full Text:
- Date Issued: 2001
- Authors: Gwayi, Noluzuko
- Date: 2001
- Subjects: Rats as laboratory animals , Rats -- physiology , Spermatozoa , Melatonin , Testis , Epididymis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5681 , http://hdl.handle.net/10962/d1005366 , Rats as laboratory animals , Rats -- physiology , Spermatozoa , Melatonin , Testis , Epididymis
- Description: Melatonin is a product of the pineal gland and is postulated to play an antigonadotropic role in the reproductive system of mammals. The reproductive system of non-seasonally breeding mammals is believed to be not as responsive to melatonin treatment as that of seasonally breeding mammals. Recently, there has been increasing support from in vivo and in vitro studies, for the hypothesis that melatonin has negative effects on sperm physiology, especially on sperm motility. High and/or low seminal concentrations of melatonin have been associated with abnormalities in human sperm motility and concentration. In this study, I examined the effects of melatonin on the testis, epididymis and sperm physiology, using in vivo and in vitro experiments, in a non-seasonally breeding mammal. Treatment, in vivo, with exogenous melatonin for six weeks did not inhibit testosterone production or spermatogenesis, nor did it affect the mass of the testes and epididymides at dissection, the concentration the morphology of speimatozoa. However, melatonin in vivo had a small, but significant negative effect on sperm motility and sperm motility index. In vitro incubation of spermatozoa Fith melatonin reduced the percentage (%) of forward progressive movement (fpm), increased the % reduction in fpm, reduced the vigor or quality of sperm motility, reduced the sperm motility index, and delayed and/or prolonged the transition of one pattern of sperm motility to the subsequent patterns. Melatonin increased the pH of the culture medium, and the increased pH, and the ethanol utilized as a solvent for melatonin, both negatively affected all the sperm motility parameters that were assessed in my study. The effects of ethanol increased with time, and the effects of pH increased with both time and increasing pH. Melatonin in vitro did not inhibit capacitation and the acrosome reaction, but it delayed the onset and the progression of capacitation and the acrosome reaction. These results suggest that while melatonin did not inhibit spermatogenesis in the Wistar rat, it may influence sperm motility. Therefore, the presence of high concentrations of melatonin in the reproductive fluids may inhibit sperm motility. With further detailed research, melatonin may have a potential use as a contraceptive drug.
- Full Text:
- Date Issued: 2001
The garden as a metaphor for paradise
- Authors: Adlard, Michelle Catherine
- Date: 2001
- Subjects: Paradise in art , Garden of paradise , Gardens -- Design -- Early works to 1800
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2391 , http://hdl.handle.net/10962/d1002187 , Paradise in art , Garden of paradise , Gardens -- Design -- Early works to 1800
- Description: In this half thesis the use of the garden as a metaphor for paradise has been explored. The English word “ paradise“ was derived from the Greek word “ paradeisos” which in turn was derived from the Old Avestana “ pairi-daeza,” meaning an enclosure. In Ancient Persia the concept applied to an enclosed garden in the modern sense of the word. For this reason the thesis begins with an examination of the development of the garden in this desert region. A more-or-less continuous chain of development in both the physical and allegorical nature of the garden is traced through history from these Ancient Persian beginnings to the height of Mughal architecture (epitomised by the Taj Mahal), by way of the Muslim expansion through Central Asia and Europe. While the core elements of garden design were set in Ancient Persian times, and recur throughout the period studied, the impact of Islam on the local Persian culture brought about a new development of allegorical meaning associated with the garden. This allegorical development reached its apex, too, in the Taj Mahal in which, it is argued, the metaphorical representation of paradise in the garden tomb was made astonishingly explicit. The research for this mini thesis was gathered from secondary sources, including many published books and academic papers, photographic and diagrammatic evidence of extant ancient gardens, and reproductions of carpet designs.
- Full Text:
- Date Issued: 2001
- Authors: Adlard, Michelle Catherine
- Date: 2001
- Subjects: Paradise in art , Garden of paradise , Gardens -- Design -- Early works to 1800
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2391 , http://hdl.handle.net/10962/d1002187 , Paradise in art , Garden of paradise , Gardens -- Design -- Early works to 1800
- Description: In this half thesis the use of the garden as a metaphor for paradise has been explored. The English word “ paradise“ was derived from the Greek word “ paradeisos” which in turn was derived from the Old Avestana “ pairi-daeza,” meaning an enclosure. In Ancient Persia the concept applied to an enclosed garden in the modern sense of the word. For this reason the thesis begins with an examination of the development of the garden in this desert region. A more-or-less continuous chain of development in both the physical and allegorical nature of the garden is traced through history from these Ancient Persian beginnings to the height of Mughal architecture (epitomised by the Taj Mahal), by way of the Muslim expansion through Central Asia and Europe. While the core elements of garden design were set in Ancient Persian times, and recur throughout the period studied, the impact of Islam on the local Persian culture brought about a new development of allegorical meaning associated with the garden. This allegorical development reached its apex, too, in the Taj Mahal in which, it is argued, the metaphorical representation of paradise in the garden tomb was made astonishingly explicit. The research for this mini thesis was gathered from secondary sources, including many published books and academic papers, photographic and diagrammatic evidence of extant ancient gardens, and reproductions of carpet designs.
- Full Text:
- Date Issued: 2001
The influence of a methylated-β-Cyclodextrin on the solubility and photostability of midazolam in aqueous solution
- Authors: Lebete, Mosimotsana Leah
- Date: 2001 , 2013-04-26
- Subjects: Midazolam -- Solubility
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3823 , http://hdl.handle.net/10962/d1005923 , Midazolam -- Solubility
- Description: Midazolam, used clinically as an anticonvulsant, anxiolytic, muscle relaxant and sedative is a photolabile imidazo-benzodiazepine which is marketed under the trade names Dormicum® and Hypnovel® as tablets and injectables. Because of an aqueous solubility of < 0.1 mg/ml above pH 4, the preparation of aqueous dosage formulations near physiological pH, requires a solubilizer. The aim of this study was thus to prepare a 10 mg/ml midazolam aqueous solution for topical application using randomly-methylated-pcyclodextrin (RAMEB), considered to be a suitable candidate as a solubilizer because of its absorption enhancing properties, and to investigate its effect on both the solubility and the photostability of midazolam. Solubility studies of midazolam (excess of 15 mg/ml) in the presence of 0, 5,10,20, 30% m/v of RAMEB at pH 5.0 and pH 5.8 (phosphate buffer) were undertaken and the results analyzed using a UV method validated for linearity, accuracy, precision and specificity. A stability-indicating HPLC method was developed and validated (precision and accuracy, linearity, range, limit of quantitation, specificity, robustness and ruggedness) for application to kinetic photostability studies and the identification of photodegradants by LC-MS. Forced degradation studies were carried out at concentrations of 0.5 mg/ml of midazolam instead of the target concentration of 10 mg/ml because of the acceleratory effect of the decreased concentration on the rate of photodegradation. The solutions of midazolam with and without RAMEB were irradiated at 550 W/m² for 12 hrs in order to degrade the drug to ± 10% of the original concentration. The UV method proved to be valid in terms of linearity with a correlation coefficient of 0.9998, precise and accurate, and specific for the determination of midazolam in the presence of RAMEB. The results of the phase solubility studies indicated that desired solubility of 10 mg/ml was achieved with 30% m/v RAMEB at pH 5.0. RAMEB slightly decreased the photostability of midazolam, the rate constants being 0.137 and 0.154 hr⁻¹ in the absence and presence of RAMEB, respectively. LC-MS analysis revealed that one of the major photoproducts in the presence and absence of RAMEB was N-desalkylflurazepam, a starting material in the synthesis of midazolam. RAMEB inhibited formation of some photoproducts and introduced two new photoproducts, a dimer and an addition product. The difference in the nature of these photoproducts formed may be attributed to the ability of RAMEB to provide conformational control and to stabilize free radicals. Although RAMEB improved the solubility of midazolam to the target concentration, photostability is decreased with the presence of different photoproducts. These studies have however provided information on the overall photostability of midazolam, the identity of its photodegradants and the photodegradation pathway in the presence and absence of RAMEB, and may be used for further method development and validation for the analysis of aqueous dosage forms containing RAMEB as a solubilizer. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 2001
- Authors: Lebete, Mosimotsana Leah
- Date: 2001 , 2013-04-26
- Subjects: Midazolam -- Solubility
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3823 , http://hdl.handle.net/10962/d1005923 , Midazolam -- Solubility
- Description: Midazolam, used clinically as an anticonvulsant, anxiolytic, muscle relaxant and sedative is a photolabile imidazo-benzodiazepine which is marketed under the trade names Dormicum® and Hypnovel® as tablets and injectables. Because of an aqueous solubility of < 0.1 mg/ml above pH 4, the preparation of aqueous dosage formulations near physiological pH, requires a solubilizer. The aim of this study was thus to prepare a 10 mg/ml midazolam aqueous solution for topical application using randomly-methylated-pcyclodextrin (RAMEB), considered to be a suitable candidate as a solubilizer because of its absorption enhancing properties, and to investigate its effect on both the solubility and the photostability of midazolam. Solubility studies of midazolam (excess of 15 mg/ml) in the presence of 0, 5,10,20, 30% m/v of RAMEB at pH 5.0 and pH 5.8 (phosphate buffer) were undertaken and the results analyzed using a UV method validated for linearity, accuracy, precision and specificity. A stability-indicating HPLC method was developed and validated (precision and accuracy, linearity, range, limit of quantitation, specificity, robustness and ruggedness) for application to kinetic photostability studies and the identification of photodegradants by LC-MS. Forced degradation studies were carried out at concentrations of 0.5 mg/ml of midazolam instead of the target concentration of 10 mg/ml because of the acceleratory effect of the decreased concentration on the rate of photodegradation. The solutions of midazolam with and without RAMEB were irradiated at 550 W/m² for 12 hrs in order to degrade the drug to ± 10% of the original concentration. The UV method proved to be valid in terms of linearity with a correlation coefficient of 0.9998, precise and accurate, and specific for the determination of midazolam in the presence of RAMEB. The results of the phase solubility studies indicated that desired solubility of 10 mg/ml was achieved with 30% m/v RAMEB at pH 5.0. RAMEB slightly decreased the photostability of midazolam, the rate constants being 0.137 and 0.154 hr⁻¹ in the absence and presence of RAMEB, respectively. LC-MS analysis revealed that one of the major photoproducts in the presence and absence of RAMEB was N-desalkylflurazepam, a starting material in the synthesis of midazolam. RAMEB inhibited formation of some photoproducts and introduced two new photoproducts, a dimer and an addition product. The difference in the nature of these photoproducts formed may be attributed to the ability of RAMEB to provide conformational control and to stabilize free radicals. Although RAMEB improved the solubility of midazolam to the target concentration, photostability is decreased with the presence of different photoproducts. These studies have however provided information on the overall photostability of midazolam, the identity of its photodegradants and the photodegradation pathway in the presence and absence of RAMEB, and may be used for further method development and validation for the analysis of aqueous dosage forms containing RAMEB as a solubilizer. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 2001