Synthesis of indium and lead phthalocyanine as photocatalysts for photodynamic antimicrobial chemotherapy and photo-oxidation of pollutants
- Authors: Osifeko, Olawale L
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/5221 , vital:20790
- Description: This thesis explores the synthesis of metallophthalocyanines as potential photosensitizers for application in photodynamic antimicrobial chemotherapy and phototransformation of environmental pollutants. The metallophthalocyanines containing amino substituent were conjugated with magnetic nanoparticle and semiconductor quantum dots via an amide bond and by chemisorption onto gold nanoparticles surface. Techniques such as time-resolved fluorescence measurements, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), elemental analysis, fourier transform infrared (FTIR), nuclear magnetic resonance (¹H, ¹³C, and cozy of symmetrical phthalocyanine), electronic spectroscopy, as well as mass spectroscopy were employed to characterize all metallophthalocyanines. Quarternized pyridyloxy substituted phthalocyanine and asymmetric (AB3) metallophthalocyanines were embedded in electrospun polystyrene fiber. General trends are described for quantum yields of fluorescence, triplet, singlet oxygen and photodegradation as well as lifetimes of fluorescence and triplet state of the compounds. There is an increase in triplet quantum yield for Pcs in the presence of gold nanoparticles (AuNPs) and semiconductor quantum dots (QDs), but not in the presence of magnetic nanoparticles (MNPs). Photodynamic inactivation of Escherichia coli with the quarternized photosensitizers at low concentrations totally inactivate the bacteria compared to non-charged photosensitiser. Also, a similar trend was observed for the magnetic nanoparticles conjugates. Photooxidations of bisphenol A and 4-chlorophenol were carried out in this study using two asymmetric Indium(III) phthalocyanines photosensitizers. The photooxidation reactions were compared with those of a symmetrical indium(III) phthalocyanines containing four quaternized 4-pyridyloxy substituents. The complexes were embedded in electrospun polystyrene fiber for heterogeneous photocatalysis. The immobilized photosensitizers possess good singlet oxygen generation potentials in aqueous media. The asymmetrical phthalocyanine containing 4-pyridylsulfanyl and one aminophenoxy showed the best photocatalytic behavior.
- Full Text:
- Authors: Osifeko, Olawale L
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/5221 , vital:20790
- Description: This thesis explores the synthesis of metallophthalocyanines as potential photosensitizers for application in photodynamic antimicrobial chemotherapy and phototransformation of environmental pollutants. The metallophthalocyanines containing amino substituent were conjugated with magnetic nanoparticle and semiconductor quantum dots via an amide bond and by chemisorption onto gold nanoparticles surface. Techniques such as time-resolved fluorescence measurements, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), elemental analysis, fourier transform infrared (FTIR), nuclear magnetic resonance (¹H, ¹³C, and cozy of symmetrical phthalocyanine), electronic spectroscopy, as well as mass spectroscopy were employed to characterize all metallophthalocyanines. Quarternized pyridyloxy substituted phthalocyanine and asymmetric (AB3) metallophthalocyanines were embedded in electrospun polystyrene fiber. General trends are described for quantum yields of fluorescence, triplet, singlet oxygen and photodegradation as well as lifetimes of fluorescence and triplet state of the compounds. There is an increase in triplet quantum yield for Pcs in the presence of gold nanoparticles (AuNPs) and semiconductor quantum dots (QDs), but not in the presence of magnetic nanoparticles (MNPs). Photodynamic inactivation of Escherichia coli with the quarternized photosensitizers at low concentrations totally inactivate the bacteria compared to non-charged photosensitiser. Also, a similar trend was observed for the magnetic nanoparticles conjugates. Photooxidations of bisphenol A and 4-chlorophenol were carried out in this study using two asymmetric Indium(III) phthalocyanines photosensitizers. The photooxidation reactions were compared with those of a symmetrical indium(III) phthalocyanines containing four quaternized 4-pyridyloxy substituents. The complexes were embedded in electrospun polystyrene fiber for heterogeneous photocatalysis. The immobilized photosensitizers possess good singlet oxygen generation potentials in aqueous media. The asymmetrical phthalocyanine containing 4-pyridylsulfanyl and one aminophenoxy showed the best photocatalytic behavior.
- Full Text:
A comparison of open source and proprietary digital forensic software
- Authors: Sonnekus, Michael Hendrik
- Date: 2015
- Subjects: Computer crimes , Computer crimes -- Investigation , Electronic evidence , Open source software
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4717 , http://hdl.handle.net/10962/d1017939
- Description: Scrutiny of the capabilities and accuracy of computer forensic tools is increasing as the number of incidents relying on digital evidence and the weight of that evidence increase. This thesis describes the capabilities of the leading proprietary and open source digital forensic tools. The capabilities of the tools were tested separately on digital media that had been formatted using Windows and Linux. Experiments were carried out with the intention of establishing whether the capabilities of open source computer forensics are similar to those of proprietary computer forensic tools, and whether these tools could complement one another. The tools were tested with regards to their capabilities to make and analyse digital forensic images in a forensically sound manner. The tests were carried out on each media type after deleting data from the media, and then repeated after formatting the media. The results of the experiments performed demonstrate that both proprietary and open source computer forensic tools have superior capabilities in different scenarios, and that the toolsets can be used to validate and complement one another. The implication of these findings is that investigators have an affordable means of validating their findings and are able to more effectively investigate digital media.
- Full Text:
- Authors: Sonnekus, Michael Hendrik
- Date: 2015
- Subjects: Computer crimes , Computer crimes -- Investigation , Electronic evidence , Open source software
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4717 , http://hdl.handle.net/10962/d1017939
- Description: Scrutiny of the capabilities and accuracy of computer forensic tools is increasing as the number of incidents relying on digital evidence and the weight of that evidence increase. This thesis describes the capabilities of the leading proprietary and open source digital forensic tools. The capabilities of the tools were tested separately on digital media that had been formatted using Windows and Linux. Experiments were carried out with the intention of establishing whether the capabilities of open source computer forensics are similar to those of proprietary computer forensic tools, and whether these tools could complement one another. The tools were tested with regards to their capabilities to make and analyse digital forensic images in a forensically sound manner. The tests were carried out on each media type after deleting data from the media, and then repeated after formatting the media. The results of the experiments performed demonstrate that both proprietary and open source computer forensic tools have superior capabilities in different scenarios, and that the toolsets can be used to validate and complement one another. The implication of these findings is that investigators have an affordable means of validating their findings and are able to more effectively investigate digital media.
- Full Text:
Newspapers' institutional voices in Zimbabwe : speaking to power through editorials between 1 June and 31 December 2013
- Authors: Nyaungwa, Mathew
- Date: 2015
- Subjects: The Herald (Zimbabwe) , NewsDay (Zimbabwe) , Editorials -- Zimbabwe , Journalism -- Political aspects -- Zimbabwe , Journalistic ethics -- Zimbabwe , Journalism -- Objectivity -- Zimbabwe , Journalism -- Zimbabwe -- 21st century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3545 , http://hdl.handle.net/10962/d1017786
- Description: This study investigates the complex role editorials – a newspaper's institutional voice – play in highly-polarised political contexts. Employing Van Dijk's insight that editorials "are usually not only, and even not primarily, directed at the common reader: rather they tend to directly or indirectly address influential news actors" (1992: 244), the study focuses on how the editorials of two Zimbabwean daily newspapers – The Herald, a perceived pro-government newspaper, and NewsDay, a perceived pro-opposition newspaper – speak to those in power. The study looks at these two newspapers' editorials from 1 June to 31 December 2013, which covers the period prior to, during and after the 2013 national elections. The 31 July, 2013 elections took place after four years of an uneasy government of national unity (GNU), which comprised ZANU-PF and the two MDC formations (Raftopoulos, 2013:978). Given the polarisation that is pervasive in the Zimbabwean politics and media, the study draws on Hallin and Mancini (2004)'s "Polarised Pluralist Model". In this model the media are used as instruments of struggle in conflicts, sometimes by dictatorships and by movements struggling against them, but also by contending parties in periods of democratic politics (Hallin and Mancini, 2004:61). Further, the methodological approach that informs this study is primarily qualitative. A qualitative content analysis of 30 editorials seeks to identify themes covered in the editorials. The study also employs a rhetorical analysis of 12 editorials and in-depth interviews and these form the adopted three-stage research design. The findings of this research somewhat contradict the common view in Zimbabwe that the privately-owned media blindly support the opposition while the stateowned media do the same to ZANU-PF (Chari, 2009:10; Mabweazara, 2011:110). Although The Herald openly supported ZANU-PF prior to the election, it shifted after the election as it pushed the ruling party to fulfill pledges made on the campaign trail. Some ZANU-PF officials were also censured by The Herald, although this selective criticism can be linked to factionalism in the party. NewsDay editorials reminded the newly formed government to mend the economy and provide basic services. While, the daily constantly censured Mugabe and ZANU-PF prior to the election, it also occasionally berated the MDC, which can be attributed to its participation in the GNU as that took away the privilege it previously had of not being hold accountable by the press.
- Full Text:
- Authors: Nyaungwa, Mathew
- Date: 2015
- Subjects: The Herald (Zimbabwe) , NewsDay (Zimbabwe) , Editorials -- Zimbabwe , Journalism -- Political aspects -- Zimbabwe , Journalistic ethics -- Zimbabwe , Journalism -- Objectivity -- Zimbabwe , Journalism -- Zimbabwe -- 21st century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3545 , http://hdl.handle.net/10962/d1017786
- Description: This study investigates the complex role editorials – a newspaper's institutional voice – play in highly-polarised political contexts. Employing Van Dijk's insight that editorials "are usually not only, and even not primarily, directed at the common reader: rather they tend to directly or indirectly address influential news actors" (1992: 244), the study focuses on how the editorials of two Zimbabwean daily newspapers – The Herald, a perceived pro-government newspaper, and NewsDay, a perceived pro-opposition newspaper – speak to those in power. The study looks at these two newspapers' editorials from 1 June to 31 December 2013, which covers the period prior to, during and after the 2013 national elections. The 31 July, 2013 elections took place after four years of an uneasy government of national unity (GNU), which comprised ZANU-PF and the two MDC formations (Raftopoulos, 2013:978). Given the polarisation that is pervasive in the Zimbabwean politics and media, the study draws on Hallin and Mancini (2004)'s "Polarised Pluralist Model". In this model the media are used as instruments of struggle in conflicts, sometimes by dictatorships and by movements struggling against them, but also by contending parties in periods of democratic politics (Hallin and Mancini, 2004:61). Further, the methodological approach that informs this study is primarily qualitative. A qualitative content analysis of 30 editorials seeks to identify themes covered in the editorials. The study also employs a rhetorical analysis of 12 editorials and in-depth interviews and these form the adopted three-stage research design. The findings of this research somewhat contradict the common view in Zimbabwe that the privately-owned media blindly support the opposition while the stateowned media do the same to ZANU-PF (Chari, 2009:10; Mabweazara, 2011:110). Although The Herald openly supported ZANU-PF prior to the election, it shifted after the election as it pushed the ruling party to fulfill pledges made on the campaign trail. Some ZANU-PF officials were also censured by The Herald, although this selective criticism can be linked to factionalism in the party. NewsDay editorials reminded the newly formed government to mend the economy and provide basic services. While, the daily constantly censured Mugabe and ZANU-PF prior to the election, it also occasionally berated the MDC, which can be attributed to its participation in the GNU as that took away the privilege it previously had of not being hold accountable by the press.
- Full Text:
A review of archean orogenic gold deposits in greenstone belts and the Slave Province : exploration in the Yellowknife domain, NWT, Canada
- Authors: Branson, Thomas Keegan
- Date: 2014
- Subjects: Gold ores -- Northwest Territories -- Yellowknife , Gold ores -- Geology , Gold mines and mining -- Northwest Territories -- Yellowknife , Greenstone belts -- Northwest Territories -- Yellowknife , Orogenic belts -- Northwest Territories -- Yellowknife , Prospecting -- Northwest Territories -- Yellowknife , Mining geology , Slave Province (N.W.T. and Nunavut)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5055 , http://hdl.handle.net/10962/d1012142 , Gold ores -- Northwest Territories -- Yellowknife , Gold ores -- Geology , Gold mines and mining -- Northwest Territories -- Yellowknife , Greenstone belts -- Northwest Territories -- Yellowknife , Orogenic belts -- Northwest Territories -- Yellowknife , Prospecting -- Northwest Territories -- Yellowknife , Mining geology , Slave Province (N.W.T. and Nunavut)
- Description: A review of Archean granite-greenstone terranes, orogenic gold deposits, the Slave Province and modern exploration tools, techniques and methods was conducted to identify prospective areas in the Yellowknife domain for hosting orogenic gold deposits and illustrate the best exploration methods for delineating this deposit type. This study identifies Archean granite-greenstone terranes as economically important hosts to quartz-carbonate vein-hosted orogenic gold deposits. These deposits occur at convergent plate margins, but can also be related to local extensional tectonics within a convergent setting. Heat generated from tectonic processes can trigger hydrothermal fluid movement along first-order faults and shear zones. Precipitation of gold-bearing quartz-carbonate veins from the hydrothermal fluids occurs in second- and third-order faults and shear zones related to the first-order structures. This study also identifies the Archean Slave Province in northern Canada as a well-endowed craton with numerous orogenic gold deposits, diamondiferous kimberlites, VMS deposits and several other mineralization styles. In particular, three greenstone belts (Yellowknife, Cameron River and Beaulieu River) associated with likely first-order structures are comprised of prospective rocks for hosting orogenic gold and VMS mineralization. The Yellowknife greenstone belt hosts the past-producing and former world-class Con and Giant orogenic gold deposits, but has been little explored with modern exploration techniques. The Cameron River and Beaulieu River greenstone belts host numerous base and precious metal VMS and BIF-hosted orogenic gold prospects and deposits, indicating mineralization is present. There is considerable potential for significant discoveries to be made using modern exploration techniques in the greenstone belts; however, exploration in the region has been hindered over the past decade by ongoing political negotiations. Once the political negotiations are finalized, application of modern exploration methods and techniques in the prospective greenstone belts should be carried out. Regional scale methodologies should be applied to generate targets using predictive modelling, implicit 3D modelling, 3D geochemistry and exploration targeting so decisions defining a businesses strategy for ground acquisition of high priority targets are made using quantitative analysis. Once ground is acquired, field-based exploration for orogenic gold and VMS deposits should include geological mapping with a focus on structural geology, geochemical sampling and airborne magnetic, radiometric and EM geophysical surveys. Prior to reconnaissance drilling, integration of all data layers and interpretation within a common 3D earth model should be conducted. Following successful reconnaissance drilling, definition drilling along strike and down dip of intersected mineralization, combined with borehole geophysics, should be carried out to delineate the extent of mineralization.
- Full Text:
- Authors: Branson, Thomas Keegan
- Date: 2014
- Subjects: Gold ores -- Northwest Territories -- Yellowknife , Gold ores -- Geology , Gold mines and mining -- Northwest Territories -- Yellowknife , Greenstone belts -- Northwest Territories -- Yellowknife , Orogenic belts -- Northwest Territories -- Yellowknife , Prospecting -- Northwest Territories -- Yellowknife , Mining geology , Slave Province (N.W.T. and Nunavut)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5055 , http://hdl.handle.net/10962/d1012142 , Gold ores -- Northwest Territories -- Yellowknife , Gold ores -- Geology , Gold mines and mining -- Northwest Territories -- Yellowknife , Greenstone belts -- Northwest Territories -- Yellowknife , Orogenic belts -- Northwest Territories -- Yellowknife , Prospecting -- Northwest Territories -- Yellowknife , Mining geology , Slave Province (N.W.T. and Nunavut)
- Description: A review of Archean granite-greenstone terranes, orogenic gold deposits, the Slave Province and modern exploration tools, techniques and methods was conducted to identify prospective areas in the Yellowknife domain for hosting orogenic gold deposits and illustrate the best exploration methods for delineating this deposit type. This study identifies Archean granite-greenstone terranes as economically important hosts to quartz-carbonate vein-hosted orogenic gold deposits. These deposits occur at convergent plate margins, but can also be related to local extensional tectonics within a convergent setting. Heat generated from tectonic processes can trigger hydrothermal fluid movement along first-order faults and shear zones. Precipitation of gold-bearing quartz-carbonate veins from the hydrothermal fluids occurs in second- and third-order faults and shear zones related to the first-order structures. This study also identifies the Archean Slave Province in northern Canada as a well-endowed craton with numerous orogenic gold deposits, diamondiferous kimberlites, VMS deposits and several other mineralization styles. In particular, three greenstone belts (Yellowknife, Cameron River and Beaulieu River) associated with likely first-order structures are comprised of prospective rocks for hosting orogenic gold and VMS mineralization. The Yellowknife greenstone belt hosts the past-producing and former world-class Con and Giant orogenic gold deposits, but has been little explored with modern exploration techniques. The Cameron River and Beaulieu River greenstone belts host numerous base and precious metal VMS and BIF-hosted orogenic gold prospects and deposits, indicating mineralization is present. There is considerable potential for significant discoveries to be made using modern exploration techniques in the greenstone belts; however, exploration in the region has been hindered over the past decade by ongoing political negotiations. Once the political negotiations are finalized, application of modern exploration methods and techniques in the prospective greenstone belts should be carried out. Regional scale methodologies should be applied to generate targets using predictive modelling, implicit 3D modelling, 3D geochemistry and exploration targeting so decisions defining a businesses strategy for ground acquisition of high priority targets are made using quantitative analysis. Once ground is acquired, field-based exploration for orogenic gold and VMS deposits should include geological mapping with a focus on structural geology, geochemical sampling and airborne magnetic, radiometric and EM geophysical surveys. Prior to reconnaissance drilling, integration of all data layers and interpretation within a common 3D earth model should be conducted. Following successful reconnaissance drilling, definition drilling along strike and down dip of intersected mineralization, combined with borehole geophysics, should be carried out to delineate the extent of mineralization.
- Full Text:
Structural bioinformatics analysis of the Hsp40 and Hsp70 molecular chaperones from humans
- Authors: Adeyemi, Samson Adebowale
- Date: 2014
- Subjects: Structural bioinformatics , Molecular chaperones , Heat shock proteins , Protein-protein interactions , Biomolecules
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4171 , http://hdl.handle.net/10962/d1020962
- Description: HSP70 is one of the most important families of molecular chaperone that regulate the folding and transport of client proteins in an ATP dependent manner. The ATPase activity of HSP70 is stimulated through an interaction with its family of HSP40 co-chaperones. There is evidence to suggest that specific partnerships occur between the different HSP40 and HSP70 isoforms. While some of the residues involved in the interaction are known, many of the residues governing the specificity of HSP40-HSP70 partnerships are not precisely defined. It is not currently possible to predict which HSP40 and HSP70 isoforms will interact. We attempted to use bioinformatics to identify residues involved in the specificity of the interaction between the J domain from HSP40 and the ATPase domain from the HSP70 isoforms from humans. A total of 49 HSP40 and 13 HSP70 sequences from humans were retrieved and used for subsequent analyses. The HSP40 J domains and HSP70 ATPase domains were extracted using python scripts and classified according to the subcellular localization of the proteins using localization prediction programs. Motif analysis was carried out using the full length HSP40 proteins and Multiple Sequence Alignment (MSA) was performed to identify conserved residues that may contribute to the J domain – ATPase domain interactions. Phylogenetic inference of the proteins was also performed in order to study their evolutionary relationship. Homology models of the J domains and ATPase domains were generated. The corresponding models were docked using HADDOCK server in order to analyze possible putative interactions between the partner proteins using the Protein Interactions Calculator (PIC). The level of residue conservation was found to be higher in Type I and II HSP40 than in Type III J proteins. While highly conserved residues on helixes II and III could play critical roles in J domain interactions with corresponding HSP70s, conserved residues on helixes I and IV seemed to be significant in keeping the J domain in its right orientation for functional interactions with HSP70s. Our results also showed that helixes II and III formed the interaction interface for binding to HSP70 ATPase domain as well as the linker residues. Finally, data based docking procedures, such as applied in this study, could be an effective method to investigate protein-protein interactions complex of biomolecules.
- Full Text:
- Authors: Adeyemi, Samson Adebowale
- Date: 2014
- Subjects: Structural bioinformatics , Molecular chaperones , Heat shock proteins , Protein-protein interactions , Biomolecules
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4171 , http://hdl.handle.net/10962/d1020962
- Description: HSP70 is one of the most important families of molecular chaperone that regulate the folding and transport of client proteins in an ATP dependent manner. The ATPase activity of HSP70 is stimulated through an interaction with its family of HSP40 co-chaperones. There is evidence to suggest that specific partnerships occur between the different HSP40 and HSP70 isoforms. While some of the residues involved in the interaction are known, many of the residues governing the specificity of HSP40-HSP70 partnerships are not precisely defined. It is not currently possible to predict which HSP40 and HSP70 isoforms will interact. We attempted to use bioinformatics to identify residues involved in the specificity of the interaction between the J domain from HSP40 and the ATPase domain from the HSP70 isoforms from humans. A total of 49 HSP40 and 13 HSP70 sequences from humans were retrieved and used for subsequent analyses. The HSP40 J domains and HSP70 ATPase domains were extracted using python scripts and classified according to the subcellular localization of the proteins using localization prediction programs. Motif analysis was carried out using the full length HSP40 proteins and Multiple Sequence Alignment (MSA) was performed to identify conserved residues that may contribute to the J domain – ATPase domain interactions. Phylogenetic inference of the proteins was also performed in order to study their evolutionary relationship. Homology models of the J domains and ATPase domains were generated. The corresponding models were docked using HADDOCK server in order to analyze possible putative interactions between the partner proteins using the Protein Interactions Calculator (PIC). The level of residue conservation was found to be higher in Type I and II HSP40 than in Type III J proteins. While highly conserved residues on helixes II and III could play critical roles in J domain interactions with corresponding HSP70s, conserved residues on helixes I and IV seemed to be significant in keeping the J domain in its right orientation for functional interactions with HSP70s. Our results also showed that helixes II and III formed the interaction interface for binding to HSP70 ATPase domain as well as the linker residues. Finally, data based docking procedures, such as applied in this study, could be an effective method to investigate protein-protein interactions complex of biomolecules.
- Full Text:
Community radio and museum outreach: a case study of community radio practices to inform the environment and sustainability programmes of Livingstone Museum
- Authors: Muloongo, Arthanitius Henry
- Date: 2011
- Subjects: Community radio -- Zambia Livingstone Museum Museum outreach programs -- Zambia Environmental education -- Zambia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1454 , http://hdl.handle.net/10962/d1003335
- Description: This is a qualitative study whose purpose was to investigate the community radio education practices and the museum outreach education activities with a view to understanding how a museum-radio partnership may be used to engage the Livingstone community in environment and sustainability learning. Environment and sustainability issues require a community approach in order to bring about sustained responses to environmental challenges. As such, the study worked with social learning ideas of engaging the community in environment and sustainability learning. The data was generated mainly from face-to-face semi-structured interviews involving three community radio stations, Radio Listener Clubs and museum experts. The data generated was then presented to a strategy workshop involving the Livingstone Museum and Radio Musi-otunya staff. Arising from this workshop, recommendations were made about the possibility of the museum working in partnership with the radio to engage the community in environmental education. The study has shown that much of the museum environmental education activities have been confined to exhibitions and lectures within the museum building, which has affected the number of people being serviced by the museum. These education activities are arranged such that museum expert-led knowledge is presented to the audience with minimal community engagement on the environmental learning content. The study has also shown that community radio programming provides opportunities for community-led social learning which the Livingstone Museum could make use of to engage the community in environmental learning. Community radio programming allows community participation through Radio Listener Clubs, in identification and presentation of local environmental issues. This makes it a suitable tool to address locally relevant environmental issues, by the local community. Environmental issues are different from one place to another. Therefore environmental education approaches that bring issues into the museum may fail to address the different environmental education issues in different community context. The study concludes by recommending that Livingstone Museum should explore the use of community radio so that their expert knowledge and that of the radio producers could be used to shape environmental education programmes to go beyond awareness-raising.
- Full Text:
- Authors: Muloongo, Arthanitius Henry
- Date: 2011
- Subjects: Community radio -- Zambia Livingstone Museum Museum outreach programs -- Zambia Environmental education -- Zambia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1454 , http://hdl.handle.net/10962/d1003335
- Description: This is a qualitative study whose purpose was to investigate the community radio education practices and the museum outreach education activities with a view to understanding how a museum-radio partnership may be used to engage the Livingstone community in environment and sustainability learning. Environment and sustainability issues require a community approach in order to bring about sustained responses to environmental challenges. As such, the study worked with social learning ideas of engaging the community in environment and sustainability learning. The data was generated mainly from face-to-face semi-structured interviews involving three community radio stations, Radio Listener Clubs and museum experts. The data generated was then presented to a strategy workshop involving the Livingstone Museum and Radio Musi-otunya staff. Arising from this workshop, recommendations were made about the possibility of the museum working in partnership with the radio to engage the community in environmental education. The study has shown that much of the museum environmental education activities have been confined to exhibitions and lectures within the museum building, which has affected the number of people being serviced by the museum. These education activities are arranged such that museum expert-led knowledge is presented to the audience with minimal community engagement on the environmental learning content. The study has also shown that community radio programming provides opportunities for community-led social learning which the Livingstone Museum could make use of to engage the community in environmental learning. Community radio programming allows community participation through Radio Listener Clubs, in identification and presentation of local environmental issues. This makes it a suitable tool to address locally relevant environmental issues, by the local community. Environmental issues are different from one place to another. Therefore environmental education approaches that bring issues into the museum may fail to address the different environmental education issues in different community context. The study concludes by recommending that Livingstone Museum should explore the use of community radio so that their expert knowledge and that of the radio producers could be used to shape environmental education programmes to go beyond awareness-raising.
- Full Text:
Exploring perceptions and implementation experiences of learner-centered education among history teachers : a case study in Namibia
- Authors: Sibeya, Nestor Mutumba
- Date: 2011
- Subjects: Student-centered education -- Namibia , History -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1988 , http://hdl.handle.net/10962/d1013226
- Description: The study sought to understand how Grade 9 History teachers perceive and implement learner-centered education (LCE) in selected schools in Caprivi educational region in the Republic of Namibia. It concentrated on three teachers in two combined and junior secondary schools. The research employed a qualitative approach and three data instruments were used: interviews, class observations and document analysis. The findings of the study show that in their interview discussions of the principles, intent and recommended key features of LCE, the three participating teachers generally correctly captured some of the essential intentions of a LCE approach. At times in the interviews they seemed to strongly grasp the essence of a key strategy and its intent, but at other times their views were sketchy. Their view of different teaching strategies at times appeared integrated but not always that strongly. When it came to their classroom practice they could and did use a number of appropriate LCE teaching approaches. The level of effectiveness in their use of many of the approaches varied from effective to far from ideal and in need of quite big improvement. In the area of resources the three classrooms were extremely limited in what they displayed, had and used. There were too few textbooks and almost no posters and wall displays on history and the geography of the world and its peoples that the students were studying. An especially interesting feature was that they all seemed to be consciously engaged in an on-going teaching experiment with the LCE approaches. The LSC [sic] practices were clearly not yet strongly imbedded as solid classroom habits or dispositions, with perhaps the exception of questioning. But this experimenting made them much more self-conscious and reflective about their experiences. They all frankly identified some tensions that they felt existed between the espoused official features of a LCE class and the demands of the covering the curriculum, size of classes etc. Overall it was an encouraging picture of teachers eager to find ways to improve their teaching and experiment with new ideas. But also a picture of people not properly exposed to good or best practice in each teaching strategy and having to reinvent and rediscover on their own even the basics of reasonable practice often making very basic mistakes, for example in questioning.
- Full Text:
- Authors: Sibeya, Nestor Mutumba
- Date: 2011
- Subjects: Student-centered education -- Namibia , History -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1988 , http://hdl.handle.net/10962/d1013226
- Description: The study sought to understand how Grade 9 History teachers perceive and implement learner-centered education (LCE) in selected schools in Caprivi educational region in the Republic of Namibia. It concentrated on three teachers in two combined and junior secondary schools. The research employed a qualitative approach and three data instruments were used: interviews, class observations and document analysis. The findings of the study show that in their interview discussions of the principles, intent and recommended key features of LCE, the three participating teachers generally correctly captured some of the essential intentions of a LCE approach. At times in the interviews they seemed to strongly grasp the essence of a key strategy and its intent, but at other times their views were sketchy. Their view of different teaching strategies at times appeared integrated but not always that strongly. When it came to their classroom practice they could and did use a number of appropriate LCE teaching approaches. The level of effectiveness in their use of many of the approaches varied from effective to far from ideal and in need of quite big improvement. In the area of resources the three classrooms were extremely limited in what they displayed, had and used. There were too few textbooks and almost no posters and wall displays on history and the geography of the world and its peoples that the students were studying. An especially interesting feature was that they all seemed to be consciously engaged in an on-going teaching experiment with the LCE approaches. The LSC [sic] practices were clearly not yet strongly imbedded as solid classroom habits or dispositions, with perhaps the exception of questioning. But this experimenting made them much more self-conscious and reflective about their experiences. They all frankly identified some tensions that they felt existed between the espoused official features of a LCE class and the demands of the covering the curriculum, size of classes etc. Overall it was an encouraging picture of teachers eager to find ways to improve their teaching and experiment with new ideas. But also a picture of people not properly exposed to good or best practice in each teaching strategy and having to reinvent and rediscover on their own even the basics of reasonable practice often making very basic mistakes, for example in questioning.
- Full Text:
Language policy and practice at CM Vellem and PJ Olivier primary schools
- Authors: Fobe, Mila Pamella
- Date: 2010
- Subjects: C M Vellem School P J Olivier School Public schools -- South Africa -- Grahamstown Language policy -- South Africa Language and education -- South Africa -- Grahamstown Native language and education -- South Africa -- Grahamstown Afrikaans language -- Study and teaching (Primary) -- South Africa -- Grahamstown Xhosa language -- Study and teaching (Primary) -- South Africa -- Grahamstown English language -- Study and teaching (Primary) -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3586 , http://hdl.handle.net/10962/d1002161
- Description: This study looks at language policy and practice at two Eastern Cape schools. It further explores the link between language learning and teaching. Language implementation strategies were the main focus of this study. The Language-in-education policy of the Republic of South Africa (1997) promotes the use of all nine African languages, which have been afforded the status of official languages. This study looks at the language teaching practices at two Grahamstown primary schools, where isiXhosa and Afrikaans have been used as media of instruction. Qualitative methods were used, and the study took the form of interpretive case studies. , Thuto e, e ikaelela go tshegetsa patlisiso e e ka ga gore dipuo tsa Selegae tsa Seaforika mo Aforikaborwa di tshwanelwa ke go tsewa ka maemo le mokgwa o o lekanang go ya ka Molaotheo wa Aforikaborwa. Ka jalo, e tlaa utolola,e ribilole ditsela le go batla malepa a puso ya Aforikaborwa e ka fitlhelelang setšhaba se se kwa magaeng, se bokgoni jwa kitso ya Seesimane bo leng kwa tlase mo go bona. Bothata ke gore Aforikaborwa e laolwa bogolo ke tiriso e e kwa godimo ya Seesimane mme puso e tshwanelwa ke gore e tlose dikgoreletsi tse di leng teng ga jaana tsa puo. E bowe gape e thibele go se lekalekaneng ga botshelo ka kakaretso mo loagong go go tlholwang ke go sa lekalekaneng ga kitso ya dipuo mo setšhabeng ka kakaretso. Ditshwanelo mo puong fela jaaka ditshwanelo dingwe le dingwe tsa botho, di tshwanelwa ke go sireletswa, jaaka di akareditswe mo Molaotheo o mošwa wa temokerasi wa Aforikaborwa.
- Full Text:
- Authors: Fobe, Mila Pamella
- Date: 2010
- Subjects: C M Vellem School P J Olivier School Public schools -- South Africa -- Grahamstown Language policy -- South Africa Language and education -- South Africa -- Grahamstown Native language and education -- South Africa -- Grahamstown Afrikaans language -- Study and teaching (Primary) -- South Africa -- Grahamstown Xhosa language -- Study and teaching (Primary) -- South Africa -- Grahamstown English language -- Study and teaching (Primary) -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3586 , http://hdl.handle.net/10962/d1002161
- Description: This study looks at language policy and practice at two Eastern Cape schools. It further explores the link between language learning and teaching. Language implementation strategies were the main focus of this study. The Language-in-education policy of the Republic of South Africa (1997) promotes the use of all nine African languages, which have been afforded the status of official languages. This study looks at the language teaching practices at two Grahamstown primary schools, where isiXhosa and Afrikaans have been used as media of instruction. Qualitative methods were used, and the study took the form of interpretive case studies. , Thuto e, e ikaelela go tshegetsa patlisiso e e ka ga gore dipuo tsa Selegae tsa Seaforika mo Aforikaborwa di tshwanelwa ke go tsewa ka maemo le mokgwa o o lekanang go ya ka Molaotheo wa Aforikaborwa. Ka jalo, e tlaa utolola,e ribilole ditsela le go batla malepa a puso ya Aforikaborwa e ka fitlhelelang setšhaba se se kwa magaeng, se bokgoni jwa kitso ya Seesimane bo leng kwa tlase mo go bona. Bothata ke gore Aforikaborwa e laolwa bogolo ke tiriso e e kwa godimo ya Seesimane mme puso e tshwanelwa ke gore e tlose dikgoreletsi tse di leng teng ga jaana tsa puo. E bowe gape e thibele go se lekalekaneng ga botshelo ka kakaretso mo loagong go go tlholwang ke go sa lekalekaneng ga kitso ya dipuo mo setšhabeng ka kakaretso. Ditshwanelo mo puong fela jaaka ditshwanelo dingwe le dingwe tsa botho, di tshwanelwa ke go sireletswa, jaaka di akareditswe mo Molaotheo o mošwa wa temokerasi wa Aforikaborwa.
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A case study: exploring students' experiences of a participative assessment approach on a professionally-orientated postgraduate programme
- Authors: du Toit, Peter
- Date: 2009
- Subjects: Education, Higher -- South Africa Graduate students -- Study and teaching -- South Africa -- Case Studies Action research in education -- South Africa -- Case Studies Universities and colleges -- Graduate work -- South Africa -- Case Studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1432 , http://hdl.handle.net/10962/d1003313
- Description: The study was undertaken as the first cycle of an action research project. It presents a case study that explores the potential of the combined use of self-, peer-, and tutor-driven assessment in enhancing students’ learning in a professionally orientated postgraduate media management course. The study also explores how such a process can contribute to students developing the skills and dispositions required by autonomous learners and professionals. In approaching these questions the study draws directly on students’ own accounts of their experiences and contrasts these accounts with the growing body of literature on participative assessment in higher education that has emerged over the past decade. The study begins by exploring how action research can aid in the development of valuable insights into educational practice. It draws on educational theorists’ use of Habermas’s (1971, 1972 and 1974 in Grundy, 1987: 8) theory of knowledge constitutive interests in developing a conceptual framework against which assessment practice can be understood and argues against instrumental approaches to assessment. Set against a background of outcomes-based education, the study presents an argument for privileging the role of assessment in promoting learning above its other function. It contends that this function is undermined if students are excluded from direct involvement in assessment practice. Informed by research into participative assessment, the study presents a thick description of a particular approach used during the action research cycle and explores how students experienced this process. The findings of the study support theories favouring the involvement of students in their own assessment and suggest that such processes can contribute to meeting students’ present and future learning needs.
- Full Text:
- Authors: du Toit, Peter
- Date: 2009
- Subjects: Education, Higher -- South Africa Graduate students -- Study and teaching -- South Africa -- Case Studies Action research in education -- South Africa -- Case Studies Universities and colleges -- Graduate work -- South Africa -- Case Studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1432 , http://hdl.handle.net/10962/d1003313
- Description: The study was undertaken as the first cycle of an action research project. It presents a case study that explores the potential of the combined use of self-, peer-, and tutor-driven assessment in enhancing students’ learning in a professionally orientated postgraduate media management course. The study also explores how such a process can contribute to students developing the skills and dispositions required by autonomous learners and professionals. In approaching these questions the study draws directly on students’ own accounts of their experiences and contrasts these accounts with the growing body of literature on participative assessment in higher education that has emerged over the past decade. The study begins by exploring how action research can aid in the development of valuable insights into educational practice. It draws on educational theorists’ use of Habermas’s (1971, 1972 and 1974 in Grundy, 1987: 8) theory of knowledge constitutive interests in developing a conceptual framework against which assessment practice can be understood and argues against instrumental approaches to assessment. Set against a background of outcomes-based education, the study presents an argument for privileging the role of assessment in promoting learning above its other function. It contends that this function is undermined if students are excluded from direct involvement in assessment practice. Informed by research into participative assessment, the study presents a thick description of a particular approach used during the action research cycle and explores how students experienced this process. The findings of the study support theories favouring the involvement of students in their own assessment and suggest that such processes can contribute to meeting students’ present and future learning needs.
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An exploration of problems experienced in the interpretation of word problems by grade 12 learners
- Authors: Neshuku, Christian N
- Date: 2009
- Subjects: Education (Secondary) -- Namibia Word problems (Mathematics) Teachers -- Training of -- Namibia Curriculum planning -- Namibia Mathematics -- Study and teaching (Secondary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1951 , http://hdl.handle.net/10962/d1008206
- Description: This research sought to investigate the problems experienced in the interpretation of word problems by senior secondary school learners, in particular to see how the language used in the articulation of word problems affects the interpretation. The study was conducted in a school in the Oshikoto region of Namibia, a school located in a semi-rural area of Namibia, and selected owing to the accessibility of the required participants. The research was located within an interpretive paradigm focusing on a study sample of 40 learners from a specified class in the selected school. Data were collected through written tests and a semi-structured interview based on written tests, and a comprehensive descriptive analysis of test results was prepared. The findings of the study indicate that the language in which the word problem was articulated did not make a difference. The performance in both English and Oshindonga tests was almost the same. The findings also indicate that vocabulary, syntactic interpretation, semantic relationships, algebraic skills, and practical sense making in relation to real-life are all important for the successful interpretation and solving of word problems. In view of these findings, the study has provided valuable insights into aspects of the teacher education curriculum that need to be revisited in order to improve the training of teachers In teaching word problems.
- Full Text:
- Authors: Neshuku, Christian N
- Date: 2009
- Subjects: Education (Secondary) -- Namibia Word problems (Mathematics) Teachers -- Training of -- Namibia Curriculum planning -- Namibia Mathematics -- Study and teaching (Secondary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1951 , http://hdl.handle.net/10962/d1008206
- Description: This research sought to investigate the problems experienced in the interpretation of word problems by senior secondary school learners, in particular to see how the language used in the articulation of word problems affects the interpretation. The study was conducted in a school in the Oshikoto region of Namibia, a school located in a semi-rural area of Namibia, and selected owing to the accessibility of the required participants. The research was located within an interpretive paradigm focusing on a study sample of 40 learners from a specified class in the selected school. Data were collected through written tests and a semi-structured interview based on written tests, and a comprehensive descriptive analysis of test results was prepared. The findings of the study indicate that the language in which the word problem was articulated did not make a difference. The performance in both English and Oshindonga tests was almost the same. The findings also indicate that vocabulary, syntactic interpretation, semantic relationships, algebraic skills, and practical sense making in relation to real-life are all important for the successful interpretation and solving of word problems. In view of these findings, the study has provided valuable insights into aspects of the teacher education curriculum that need to be revisited in order to improve the training of teachers In teaching word problems.
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A VLBI study of OH masers in a proto-planetary nebula OH 0.9+1.3
- Authors: McAlpine, Kim
- Date: 2008
- Subjects: Very long baseline interferometry , Proto-planetary nebulae , Masers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5499 , http://hdl.handle.net/10962/d1005285 , Very long baseline interferometry , Proto-planetary nebulae , Masers
- Description: This thesis reports the calibration, imaging and analysis of one epoch of VLBA observations of the 1612 MHz OH maser emission from the protoplanetary nebula OH 0.9+1.3. These are the first polarisation VLBI observations of this source and the spatial morphology of the OH emission is resolved on this scale. Proto-planetary nebulae represent the transition phase in the evolution of stars between the asymptotic giant branch (AGB) phase and their emergence as planetary nebulae. A long-standing astronomical question is how the predominantly spherical circumstellar envelopes of AGB stars evolve into the bipolar and axisymmetric structures that are commonly observed in planetary nebula. Proto-planetary nebulae offer a unique opportunity to study this transformation process. The high-resolution VLBI maps produced in this thesis were used to investigate the morphology and kinematics of OH 0.9+1.3 with a view to gaining insight into the development of asymmetries in the circumstellar material. The OH maser emission of OH 0.9+1.3 has a double-peaked profile with one peak blue-shifted and the other red-shifted with respect to the stellar velocity. The total intensity maser maps demonstrate a considerable degree of asymmetry with the blue- and red-shifted emission located in spatially distinct regions of the envelope. The blue-shifted emission is distributed preferentially along an axis at a projected position angle of » 135± ( North through East). The morphology of this source is not consistent with the standard symmetric thin-shell model and an attempt to fit the traditional OH/IR kinematic model of a simple expanding shell to the maser components was found to be unsatisfactory. No definitive evidence of a bipolar outflow was observed either. The high degree of asymmetry observed in the source is consistent with its status as a proto-planetary nebula. The source was imaged in all four Stokes parameters and the fractional linear and circular polarisations of the maser components were derived from the Stokes parameter maps. In all except one of the components the total fractional polarisation was found to be low ( < 15%). The mean fractional linear and circular polarisation were calculated to be 5.54% and 7.11% respectively. The absence of an identifiable Zeeman pair in the Stokes V map prohibited the estimation of the magnetic field in the circumstellar envelope of this source.
- Full Text:
- Authors: McAlpine, Kim
- Date: 2008
- Subjects: Very long baseline interferometry , Proto-planetary nebulae , Masers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5499 , http://hdl.handle.net/10962/d1005285 , Very long baseline interferometry , Proto-planetary nebulae , Masers
- Description: This thesis reports the calibration, imaging and analysis of one epoch of VLBA observations of the 1612 MHz OH maser emission from the protoplanetary nebula OH 0.9+1.3. These are the first polarisation VLBI observations of this source and the spatial morphology of the OH emission is resolved on this scale. Proto-planetary nebulae represent the transition phase in the evolution of stars between the asymptotic giant branch (AGB) phase and their emergence as planetary nebulae. A long-standing astronomical question is how the predominantly spherical circumstellar envelopes of AGB stars evolve into the bipolar and axisymmetric structures that are commonly observed in planetary nebula. Proto-planetary nebulae offer a unique opportunity to study this transformation process. The high-resolution VLBI maps produced in this thesis were used to investigate the morphology and kinematics of OH 0.9+1.3 with a view to gaining insight into the development of asymmetries in the circumstellar material. The OH maser emission of OH 0.9+1.3 has a double-peaked profile with one peak blue-shifted and the other red-shifted with respect to the stellar velocity. The total intensity maser maps demonstrate a considerable degree of asymmetry with the blue- and red-shifted emission located in spatially distinct regions of the envelope. The blue-shifted emission is distributed preferentially along an axis at a projected position angle of » 135± ( North through East). The morphology of this source is not consistent with the standard symmetric thin-shell model and an attempt to fit the traditional OH/IR kinematic model of a simple expanding shell to the maser components was found to be unsatisfactory. No definitive evidence of a bipolar outflow was observed either. The high degree of asymmetry observed in the source is consistent with its status as a proto-planetary nebula. The source was imaged in all four Stokes parameters and the fractional linear and circular polarisations of the maser components were derived from the Stokes parameter maps. In all except one of the components the total fractional polarisation was found to be low ( < 15%). The mean fractional linear and circular polarisation were calculated to be 5.54% and 7.11% respectively. The absence of an identifiable Zeeman pair in the Stokes V map prohibited the estimation of the magnetic field in the circumstellar envelope of this source.
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Challenges faced by secondary school teachers in integrating ICT into the curriculum: a multiple case study in the Grahamstown Circuit
- Maholwana-Sotashe, Nikiwe Laura
- Authors: Maholwana-Sotashe, Nikiwe Laura
- Date: 2008
- Subjects: Educational technology -- South Africa -- Grahamstown Education, Secondary -- South Africa -- Grahamstown -- Data processing Information technology -- Study and teaching (Secondary) -- South Africa -- Grahamstown Internet in education -- South Africa -- Grahamstown Information technology -- South Africa -- Grahamstown Computer-assisted instruction -- South Africa -- Grahamstown Education, Secondary -- Curricula -- South Africa -- Grahamstown Educational innovations
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1445 , http://hdl.handle.net/10962/d1003326
- Description: The integration of Information and Communication Technology (ICT) into the curriculum has become the major issue worldwide. The education system does not only pursue the integration of ICT into the curriculum because of its popularity in the market system, but because of the role it is perceived to play in the changing curriculum (encourages active construction of knowledge). According to White Paper 7 e-Education policy (2004:17) every South African learner should be able to use ICTs confidently and creatively to develop the skills and knowledge they need to achieve personal goals and to be full participants in the global community by 2013. The central role played by teachers in teaching and learning requires them to have a holistic understanding of ICT integration. Furthermore they should be able to analyse when ICT integration is appropriate according to what is expected from the learner in the teaching and learning process. Drawing on the evidence from a survey of nine secondary schools in the Grahamstown Circuit of the Eastern Cape, this study examines how teachers from three different types of secondary schools: Former Department of Education (FDET) schools, Former House of Representatives (FHOR) schools and Former Model C (FMC) schools perceive the integration of ICTs in the curriculum. The salient ideas of how teachers perceive the integration of ICTs into the curriculum emerge from what they view as benefits of using ICT and what they view as challenges of integrating ICT into the curriculum. Contrary to expectations, the degree of ICT integration within the curriculum did not correspond directly with the availability of sufficient hardware, software or Internet connectivity at the participating schools.
- Full Text:
- Authors: Maholwana-Sotashe, Nikiwe Laura
- Date: 2008
- Subjects: Educational technology -- South Africa -- Grahamstown Education, Secondary -- South Africa -- Grahamstown -- Data processing Information technology -- Study and teaching (Secondary) -- South Africa -- Grahamstown Internet in education -- South Africa -- Grahamstown Information technology -- South Africa -- Grahamstown Computer-assisted instruction -- South Africa -- Grahamstown Education, Secondary -- Curricula -- South Africa -- Grahamstown Educational innovations
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1445 , http://hdl.handle.net/10962/d1003326
- Description: The integration of Information and Communication Technology (ICT) into the curriculum has become the major issue worldwide. The education system does not only pursue the integration of ICT into the curriculum because of its popularity in the market system, but because of the role it is perceived to play in the changing curriculum (encourages active construction of knowledge). According to White Paper 7 e-Education policy (2004:17) every South African learner should be able to use ICTs confidently and creatively to develop the skills and knowledge they need to achieve personal goals and to be full participants in the global community by 2013. The central role played by teachers in teaching and learning requires them to have a holistic understanding of ICT integration. Furthermore they should be able to analyse when ICT integration is appropriate according to what is expected from the learner in the teaching and learning process. Drawing on the evidence from a survey of nine secondary schools in the Grahamstown Circuit of the Eastern Cape, this study examines how teachers from three different types of secondary schools: Former Department of Education (FDET) schools, Former House of Representatives (FHOR) schools and Former Model C (FMC) schools perceive the integration of ICTs in the curriculum. The salient ideas of how teachers perceive the integration of ICTs into the curriculum emerge from what they view as benefits of using ICT and what they view as challenges of integrating ICT into the curriculum. Contrary to expectations, the degree of ICT integration within the curriculum did not correspond directly with the availability of sufficient hardware, software or Internet connectivity at the participating schools.
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Education in the wetlands and wetlands in the education: a case of contextualizing primary/basic education in Tanzania
- Authors: Hogan, Alice Rosemary
- Date: 2008
- Subjects: Education -- Tanzania Environmental education -- Tanzania Education, Rural -- Tanzania Education -- Curricula -- Tanzania Community and school -- Tanzania
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1504 , http://hdl.handle.net/10962/d1003386
- Description: This dissertation describes an action research case study carried out at a sub-village school at Nyamakurukuru, Utete, Rufiji District, Tanzania. The study was a fully independent research activity funded and led by a female Irish environmental and community specialist who has fifteen years experience of working in rural Tanzania, five of which were in Rufiji District. The aim of the action research was to engage a community of villagers, teachers, students and district officers in a participatory process to adapt a module of a school curriculum to the local context, and teach it in order to describe one way in which contextualization, using local and indigenous knowledge and active discovery teaching-learning processes, can be done. The major research question, which I wished to answer for one specific case, was: Does integrating local environmental cultural knowledge into formal schooling contribute to curriculum relevance? If so, in what way? This document describes the background and context of the research, the motivation and the theoretical basis for the work, the methodology and methods, and the action research process itself. The results are interpreted and discussed in the light of current theoretical perspectives on education and environmental education. The main findings within the case are that: Contextualization improved relevance of education and thus its quality by: • breaking through traditional frames/barriers between teachers and students, students and elders and community and teachers, • allowing formal education to take place outside of the school, • necessitating a change in pedagogy1 to more learner-centered, discovery methods, • allowing indigenous knowledge to come into the classroom, • stimulating creativity and increased confidence, and • bringing local socio-political environmental issues into the classroom. This study provides a case example of how education processes, when engaging local cultural knowledge, can improve the relevance, and thus an aspect of the quality of teaching and learning in school-community contexts, while providing a conduit for integrating environmental education into the formal school curriculum. It provides insights into the key issue of relevance which currently faces educators of children in wetlands in Tanzania. Recommendations were made for the case studied and may be useful beyond the boundaries of the case: • Give more explicit government policy and strategic support for community involvement in educational content–epistemologies and pedagogies. • Weaken framing (hierarchical power positions) to encourage greater partnership between school, home and community to improve relevance. • Investigate the provision of education beyond schools. • Provide practical teacher and community training on use of learner-centered, discovery and active pedagogies. • Provide teacher and community education on biodiversity and the environment. • Provide relevant reference texts and research data on the ecology, biodiversity, vegetation, hydrology, agriculture, sociology, history and other relevant subjects. • Officially nurture a culture that learning should be enjoyable. • Allow the curriculum freedom, in these times of increasing risk for rural tropical wetland communities, to make the curriculum fit the local issues rather than vice versa. • Nurture critical analysis of the curriculum in local pedagogic discourse i.e., at the local contextualization level of the home, community and school.
- Full Text:
- Authors: Hogan, Alice Rosemary
- Date: 2008
- Subjects: Education -- Tanzania Environmental education -- Tanzania Education, Rural -- Tanzania Education -- Curricula -- Tanzania Community and school -- Tanzania
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1504 , http://hdl.handle.net/10962/d1003386
- Description: This dissertation describes an action research case study carried out at a sub-village school at Nyamakurukuru, Utete, Rufiji District, Tanzania. The study was a fully independent research activity funded and led by a female Irish environmental and community specialist who has fifteen years experience of working in rural Tanzania, five of which were in Rufiji District. The aim of the action research was to engage a community of villagers, teachers, students and district officers in a participatory process to adapt a module of a school curriculum to the local context, and teach it in order to describe one way in which contextualization, using local and indigenous knowledge and active discovery teaching-learning processes, can be done. The major research question, which I wished to answer for one specific case, was: Does integrating local environmental cultural knowledge into formal schooling contribute to curriculum relevance? If so, in what way? This document describes the background and context of the research, the motivation and the theoretical basis for the work, the methodology and methods, and the action research process itself. The results are interpreted and discussed in the light of current theoretical perspectives on education and environmental education. The main findings within the case are that: Contextualization improved relevance of education and thus its quality by: • breaking through traditional frames/barriers between teachers and students, students and elders and community and teachers, • allowing formal education to take place outside of the school, • necessitating a change in pedagogy1 to more learner-centered, discovery methods, • allowing indigenous knowledge to come into the classroom, • stimulating creativity and increased confidence, and • bringing local socio-political environmental issues into the classroom. This study provides a case example of how education processes, when engaging local cultural knowledge, can improve the relevance, and thus an aspect of the quality of teaching and learning in school-community contexts, while providing a conduit for integrating environmental education into the formal school curriculum. It provides insights into the key issue of relevance which currently faces educators of children in wetlands in Tanzania. Recommendations were made for the case studied and may be useful beyond the boundaries of the case: • Give more explicit government policy and strategic support for community involvement in educational content–epistemologies and pedagogies. • Weaken framing (hierarchical power positions) to encourage greater partnership between school, home and community to improve relevance. • Investigate the provision of education beyond schools. • Provide practical teacher and community training on use of learner-centered, discovery and active pedagogies. • Provide teacher and community education on biodiversity and the environment. • Provide relevant reference texts and research data on the ecology, biodiversity, vegetation, hydrology, agriculture, sociology, history and other relevant subjects. • Officially nurture a culture that learning should be enjoyable. • Allow the curriculum freedom, in these times of increasing risk for rural tropical wetland communities, to make the curriculum fit the local issues rather than vice versa. • Nurture critical analysis of the curriculum in local pedagogic discourse i.e., at the local contextualization level of the home, community and school.
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A genetic and ecophysiological comparison of co-occuring indigenous (Perna perna) and invasive (Mytilus galloprovincialis) intertidal mussels
- Authors: Zardi, Gerardo Ivan
- Date: 2006
- Subjects: Perna -- South Africa Mytilus galloprovincialis -- South Africa Mussels -- South Africa Mytilidae -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5613 , http://hdl.handle.net/10962/d1003066
- Description: The Mediterranean mussel Mytilus galloprovincialis is the most successful marine invasive species in South Africa. Its presence has had significant ecological consequences on the intertidal communities of the west coast. On the south coast, M galloprovincialis co-exists and competes with the indigenous intertidal mussel Perna perna in the lower balanoid zone, where they show partial habitat segregation. The upper and the lower mussel zones are dominated by M. galloprovincialis and P. perna respectively while they co-occur in the mid zone. In this thesis M. galloprovincialis and P. perna are compared in terms of their population genetics and their ecophysiology. The success of an invader depends on its ability to react to new environmental factors, especially when compared to indigenous species. The distribution and diversity of intertidal species throughout the world are strongly influenced by periodic sand inundation and hydrodynamic stress. Occupying the lower intertidal zone, P. perna is more strongly influenced by sand (burial and sand in suspension) than M. galioprovincialis. Despite this, P. perna is more vulnerable to the effects of sand, showing higher mortality rates under experimental conditions in both the laboratory and the field. M. galioprovincialis has longer labial palps than P. perna, indicating a better ability to sort particles. This, and a higher tolerance to anoxia, explains its lower mortality rates when exposed to burial or suspended sand. Habitat segregation is often explained by physiological tolerances, but in this case, such explanations fail. The ability of a mussel to withstand wave-generated hydrodynamic stress depends mainly on its byssal attachment strength. The higher attachment strength of P. perna compared to M. galioprovincialis and of solitary mussels compared to mussels living within a bed (bed mussels) can be explained by more and thicker byssal threads. M galloprovincialis also has a wider shell, is subjected to higher hydrodynamic loads than P. perna and shows a higher theoretical probability of dislodgement, this is borne out under field conditions. The attachment strength of both species increased from higher to lower shore, in parallel to a gradient of a stronger wave action. Monthly measurements showed that P. perna is always more strongly attached than M. galloprovincialis and revealed seasonal fluctuations of attachment strength for both species in response to wave height. The gonad index of both species was negatively cross-correlated with attachment strength. The results are discussed in the context of the evolutionary strategy of the alien mussel, which directs most of its energy to fast growth and high reproductive output, apparently at the cost of reduced attachment strength. This raises the prediction that its invasive impact will be more pronounced at sites subjected to low or moderate wave action at heavily exposed sites. The potential of a species for invasion is also determined by the ability of the invader to disperse. Population genetics provide indirect information about dispersal through a direct measurement of gene flow. The low genetic divergence (measured as mtDNA) of M. galloprovincialis confirms its recent arrival in South Africa. In contrast, the population genetics structure of P. perna revealed strong divergence on the south-east coast, resulting in a western lineage (straddling the distributional gap of the Benguela System), and an eastern lineage, with an overlap region of the two on the south coast between Kenton-on-Sea and Haga Haga. This genetic disjunction may be caused by Agulhas Current acting as an oceanographic barrier to larval dispersal, or by different environmental selective forces acting on regional populations. Over the last ten years, M. galloprovincialis has shown a decrease or cessation of its spread to the east in exactly the region of the genetic disjunction in P. perna, again suggesting either an oceanographic barrier to larval dispersal, or increasing selection driven by sharp gradients in environmental conditions.
- Full Text:
- Authors: Zardi, Gerardo Ivan
- Date: 2006
- Subjects: Perna -- South Africa Mytilus galloprovincialis -- South Africa Mussels -- South Africa Mytilidae -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5613 , http://hdl.handle.net/10962/d1003066
- Description: The Mediterranean mussel Mytilus galloprovincialis is the most successful marine invasive species in South Africa. Its presence has had significant ecological consequences on the intertidal communities of the west coast. On the south coast, M galloprovincialis co-exists and competes with the indigenous intertidal mussel Perna perna in the lower balanoid zone, where they show partial habitat segregation. The upper and the lower mussel zones are dominated by M. galloprovincialis and P. perna respectively while they co-occur in the mid zone. In this thesis M. galloprovincialis and P. perna are compared in terms of their population genetics and their ecophysiology. The success of an invader depends on its ability to react to new environmental factors, especially when compared to indigenous species. The distribution and diversity of intertidal species throughout the world are strongly influenced by periodic sand inundation and hydrodynamic stress. Occupying the lower intertidal zone, P. perna is more strongly influenced by sand (burial and sand in suspension) than M. galioprovincialis. Despite this, P. perna is more vulnerable to the effects of sand, showing higher mortality rates under experimental conditions in both the laboratory and the field. M. galioprovincialis has longer labial palps than P. perna, indicating a better ability to sort particles. This, and a higher tolerance to anoxia, explains its lower mortality rates when exposed to burial or suspended sand. Habitat segregation is often explained by physiological tolerances, but in this case, such explanations fail. The ability of a mussel to withstand wave-generated hydrodynamic stress depends mainly on its byssal attachment strength. The higher attachment strength of P. perna compared to M. galioprovincialis and of solitary mussels compared to mussels living within a bed (bed mussels) can be explained by more and thicker byssal threads. M galloprovincialis also has a wider shell, is subjected to higher hydrodynamic loads than P. perna and shows a higher theoretical probability of dislodgement, this is borne out under field conditions. The attachment strength of both species increased from higher to lower shore, in parallel to a gradient of a stronger wave action. Monthly measurements showed that P. perna is always more strongly attached than M. galloprovincialis and revealed seasonal fluctuations of attachment strength for both species in response to wave height. The gonad index of both species was negatively cross-correlated with attachment strength. The results are discussed in the context of the evolutionary strategy of the alien mussel, which directs most of its energy to fast growth and high reproductive output, apparently at the cost of reduced attachment strength. This raises the prediction that its invasive impact will be more pronounced at sites subjected to low or moderate wave action at heavily exposed sites. The potential of a species for invasion is also determined by the ability of the invader to disperse. Population genetics provide indirect information about dispersal through a direct measurement of gene flow. The low genetic divergence (measured as mtDNA) of M. galloprovincialis confirms its recent arrival in South Africa. In contrast, the population genetics structure of P. perna revealed strong divergence on the south-east coast, resulting in a western lineage (straddling the distributional gap of the Benguela System), and an eastern lineage, with an overlap region of the two on the south coast between Kenton-on-Sea and Haga Haga. This genetic disjunction may be caused by Agulhas Current acting as an oceanographic barrier to larval dispersal, or by different environmental selective forces acting on regional populations. Over the last ten years, M. galloprovincialis has shown a decrease or cessation of its spread to the east in exactly the region of the genetic disjunction in P. perna, again suggesting either an oceanographic barrier to larval dispersal, or increasing selection driven by sharp gradients in environmental conditions.
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In vitro passage of ibuprofen through synthetic and biological membranes
- Authors: Purdon, Carryn Hamilton
- Date: 2001
- Subjects: Ibuprofen , Diffusion processes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3786 , http://hdl.handle.net/10962/d1003264 , Ibuprofen , Diffusion processes
- Description: Ibuprofen is a non-steroidal anti-inflammatory drug with three major types of effect: anti-inflammatory, analgesic and antipyretic. Ibuprofen may be administered in a number of different forms via the oral as well as the topical route. Published evidence suggests that topical, unlike oral, non-steroidal anti-inflammatory drugs are associated with few systemic side effects as plasma concentrations are low compared to oral therapy. In some countries it is particularly difficult to obtain human skin for in vitro experimentation and it is therefore important to have alternate biological or synthetic membranes which mimic human skin for diffusion experiments. Synthetic membranes serve as predictive models for topical drug release and in South Africa, shed snake skin is easily obtainable from the many snake parks present in the country. The FDA guidelines were considered when choosing the apparatus to be used in the comparative diffusion study on proprietary ibuprofen-containing topical preparations from three countries and the verification of the usefulness, or otherwise, of shed snake skin as a biological membrane for the assessment of the permeation of ibuprofen. Two diffusion techniques were considered appropriate for the measurement of the amount of ibuprofen released from a topical formulation during in vitro testing. One was the Franz diffusion cell, as modified by Keshary and Chien (88,169) and the other was the European Pharmacopoeia diffusion cell (187). High performance liquid chromatography was used as the analytical technique for the analysis of ibuprofen in aqueous solution using ultraviolet detection at 222 nm. The validated method was applied to the determination of the diffusion of ibuprofen from topical ibuprofen-containing formulations (gels, creams and mousse) through synthetic silicone membrane and shed snake skin biological membrane from four different species. In a study of fifteen topical ibuprofen-containing formulations (gels, creams and mousse) from three countries (South Africa, United Kingdom and France) it was found that there was a trend of products from two countries consistently exhibiting superior diffusion characteristics as well as products from the same two countries consistently exhibiting the lowest diffusion of ibuprofen. Interpretation of the results of these studies demonstrated the importance of employing a combination of statistical analyses and peak integration values when drawing conclusions regarding comparative diffusion characteristics. Shed snake skin has been described as a 'model' membrane, i.e. a membrane which shows similar permeability to human stratum corneum. The results reported here show clearly that, for ibuprofen, the four species of snake produce shed skin with completely different diffusion characteristics when all other conditions are identical. It may well be that there is one particular species of snake which produces shed skin of identical permeability to human stratum corneum, but to describe shed snake skin in general as a model membrane seems incorrect. It is therefore important that if shed snake skin is used as a membrane, the species, skin site and orientation should be reported. The European Pharmacopoeia diffusion apparatus was judged to be the better of the two diffusion techniques assessed for the measurement of the amount of ibuprofen released from a topical formulation during in vitro testing using silicone membranes and for the measurement of the amount of ibuprofen diffusing across the ventral outside orientation of shed skin during in vitro testing, whereas the Franz diffusion apparatus was judged to be better for the measurement of the amount of ibuprofen diffusing across the dorsal outside orientation of shed skin during in vitro testing. However, the choice of this diffusion apparatus must be weighed against the relatively poor reproducibility as compared with the European Pharmacopoeia diffusion apparatus.
- Full Text:
- Authors: Purdon, Carryn Hamilton
- Date: 2001
- Subjects: Ibuprofen , Diffusion processes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3786 , http://hdl.handle.net/10962/d1003264 , Ibuprofen , Diffusion processes
- Description: Ibuprofen is a non-steroidal anti-inflammatory drug with three major types of effect: anti-inflammatory, analgesic and antipyretic. Ibuprofen may be administered in a number of different forms via the oral as well as the topical route. Published evidence suggests that topical, unlike oral, non-steroidal anti-inflammatory drugs are associated with few systemic side effects as plasma concentrations are low compared to oral therapy. In some countries it is particularly difficult to obtain human skin for in vitro experimentation and it is therefore important to have alternate biological or synthetic membranes which mimic human skin for diffusion experiments. Synthetic membranes serve as predictive models for topical drug release and in South Africa, shed snake skin is easily obtainable from the many snake parks present in the country. The FDA guidelines were considered when choosing the apparatus to be used in the comparative diffusion study on proprietary ibuprofen-containing topical preparations from three countries and the verification of the usefulness, or otherwise, of shed snake skin as a biological membrane for the assessment of the permeation of ibuprofen. Two diffusion techniques were considered appropriate for the measurement of the amount of ibuprofen released from a topical formulation during in vitro testing. One was the Franz diffusion cell, as modified by Keshary and Chien (88,169) and the other was the European Pharmacopoeia diffusion cell (187). High performance liquid chromatography was used as the analytical technique for the analysis of ibuprofen in aqueous solution using ultraviolet detection at 222 nm. The validated method was applied to the determination of the diffusion of ibuprofen from topical ibuprofen-containing formulations (gels, creams and mousse) through synthetic silicone membrane and shed snake skin biological membrane from four different species. In a study of fifteen topical ibuprofen-containing formulations (gels, creams and mousse) from three countries (South Africa, United Kingdom and France) it was found that there was a trend of products from two countries consistently exhibiting superior diffusion characteristics as well as products from the same two countries consistently exhibiting the lowest diffusion of ibuprofen. Interpretation of the results of these studies demonstrated the importance of employing a combination of statistical analyses and peak integration values when drawing conclusions regarding comparative diffusion characteristics. Shed snake skin has been described as a 'model' membrane, i.e. a membrane which shows similar permeability to human stratum corneum. The results reported here show clearly that, for ibuprofen, the four species of snake produce shed skin with completely different diffusion characteristics when all other conditions are identical. It may well be that there is one particular species of snake which produces shed skin of identical permeability to human stratum corneum, but to describe shed snake skin in general as a model membrane seems incorrect. It is therefore important that if shed snake skin is used as a membrane, the species, skin site and orientation should be reported. The European Pharmacopoeia diffusion apparatus was judged to be the better of the two diffusion techniques assessed for the measurement of the amount of ibuprofen released from a topical formulation during in vitro testing using silicone membranes and for the measurement of the amount of ibuprofen diffusing across the ventral outside orientation of shed skin during in vitro testing, whereas the Franz diffusion apparatus was judged to be better for the measurement of the amount of ibuprofen diffusing across the dorsal outside orientation of shed skin during in vitro testing. However, the choice of this diffusion apparatus must be weighed against the relatively poor reproducibility as compared with the European Pharmacopoeia diffusion apparatus.
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Key decision-makers' perceptions of sustainable sea fisheries in Namibia and the implications for environmental education programmes
- Authors: Boois, Ulrich
- Date: 2000
- Subjects: Environmental education -- Namibia Fisheries -- Environmental aspects Fisheries -- Environmental aspects -- Namibia Sustainable development -- Environmental aspects Sustainable development -- Environmental aspects -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1661 , http://hdl.handle.net/10962/d1003544
- Description: This study investigates key decision-makers' perceptions of sustainable sea fisheries in Namibia, and explores the possibilities for the future development of education programmes that focus on "sustainability" in the fisheries sector. The concept of "sustainability" and its application in the context of a biological resource, namely sea fisheries, was examined. A series of questions were raised concerning sustainable fisheries: intergenerational implications of patterns of resource use, equity concerns, time horizons, and the protection of marine biodiveristy, among others. Examples from the Namibian and the European Community Sea Fisheries Industries are used to illustrate these issues. In spite of divergent views on what "sustainability" means, the study leads to certain findings that have broader policy implications. Data was collected from semi-structured interviews undertaken with six (6) key decision-makers in the Sea Fisheries Industry of Namibia, then analysed and assessed. The perceptions of key decisionmakers were determined by qualitative analysis in the interpretive paradigm. The data indicated some agreement in terms of what the key decision-makers think about the sustainable utilisation of the fisherjes resources. It is almost impossible to have complete agreement, because the decision-makers are from different contextual backgrounds. Those who make the decisions are more concerned about "how to manage" and those who act on the decisions put more emphasis on economic self-interest. Although the interviewees' perceptions of sustainable fisheries was imperfect, there was broad support for its aims and principles. The study also revealed that the achievement of sustainable sea fisheries development in Wamibia will require broader educational and public awareness programmes to enhance participation in decision-making debates. Formal and informal marine environmental education, from the perspective of "Responsible Fishing" has been emphasised.
- Full Text:
- Authors: Boois, Ulrich
- Date: 2000
- Subjects: Environmental education -- Namibia Fisheries -- Environmental aspects Fisheries -- Environmental aspects -- Namibia Sustainable development -- Environmental aspects Sustainable development -- Environmental aspects -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1661 , http://hdl.handle.net/10962/d1003544
- Description: This study investigates key decision-makers' perceptions of sustainable sea fisheries in Namibia, and explores the possibilities for the future development of education programmes that focus on "sustainability" in the fisheries sector. The concept of "sustainability" and its application in the context of a biological resource, namely sea fisheries, was examined. A series of questions were raised concerning sustainable fisheries: intergenerational implications of patterns of resource use, equity concerns, time horizons, and the protection of marine biodiveristy, among others. Examples from the Namibian and the European Community Sea Fisheries Industries are used to illustrate these issues. In spite of divergent views on what "sustainability" means, the study leads to certain findings that have broader policy implications. Data was collected from semi-structured interviews undertaken with six (6) key decision-makers in the Sea Fisheries Industry of Namibia, then analysed and assessed. The perceptions of key decisionmakers were determined by qualitative analysis in the interpretive paradigm. The data indicated some agreement in terms of what the key decision-makers think about the sustainable utilisation of the fisherjes resources. It is almost impossible to have complete agreement, because the decision-makers are from different contextual backgrounds. Those who make the decisions are more concerned about "how to manage" and those who act on the decisions put more emphasis on economic self-interest. Although the interviewees' perceptions of sustainable fisheries was imperfect, there was broad support for its aims and principles. The study also revealed that the achievement of sustainable sea fisheries development in Wamibia will require broader educational and public awareness programmes to enhance participation in decision-making debates. Formal and informal marine environmental education, from the perspective of "Responsible Fishing" has been emphasised.
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A study of the burrowing sandprawn Callianassa kraussi Stebbing (Crustacea - Decapoda - Thalassinidea)
- Authors: Forbes, Anthony Tonks
- Date: 1974
- Subjects: Estuarine biology -- South Africa Shrimps -- South Africa Decapoda (Crustacea) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5850 , http://hdl.handle.net/10962/d1011866
- Description: The distribution of Callianassa kraussi in southern Africa extends from Lamberts Bay on the west coast to San Martinho in Mocambique. This represents a northerly extension of the range from the previous known limit of Inhaca Island. In this area 59 localities were visited and records obtained for an additional 16. Three areas were selected for detailed study. These were the west Kleinemonde estuary, which is normally closed off from the sea by a sand bar and the open Swartkops estuary both on the southeastern Cape coast, and the Swartvlei system, which consists of a lake connected to the sea by a channel which closes intermittently, on the southern Cape coast. The nature of the burrows constructed by C. kraussi was investigated in these areas. Burrow complexes may have up to nine entrances but more commonly two to four. Laboratory studies suggest that the number of entrances does not exceed the number of prawns present and consequently burrow opening counts will give an estimate of population density. Water movement can result in the closing off of burrows while strong water and sand movement will exclude C.kraussi from an area. C.kraussi is also excluded from areas which have very coarse substrates. A three year regular sampling program showed that C.kraussi breeds mainly in winter/spring with a smaller breeding peak in summer. Egg development time at 20°C in a salinity of 35° /₀₀ is 30-33 days. There are two larval stages which last 3-5 days. Development time of the eggs is tripled at temperatures of 13-15°C while larval development time is extended to 9-14 days. Development is possibly slightly accelerated at 25 ± 3°C but the number of eggs hatching is markedly reduced. Larval development times were similar to those at 20° and 35°/₀₀. There are no planktonic larval stages. Growth was more rapid and greater size was attained in the open Swartkops estuary than in the closed Kleinemonde estuary. Prawns hatching in winter/spring breed for the first time in the following summer at an age of about 16 months and then again in the following winter/spring at an age of about 2 years. Prawns hatching in summer breed in the following winter at an age of about 18 months and then again in the immediately following summer. Longevity in both sexes is about 2 years. Dispersal is accomplished by migration of the post-larval juvenile phases at an age of 3-5 months. Non-selfmaintaining populations exist in areas where salinities are too low to permit breeding. Population densities were found to vary markedly in different areas. Investigations of osmotic and ionic regulation showed that C.kraussi is a strong hyper-regulator and thus distinct from any other known species in the genus. Volume regulatory ability is well developed and depends on variable rates of urine production. Salt loss in dilutions occurs almost equally via the gills and the urine. The general responses of C.kraussi to dilutions of sea water are discussed. Various suggestions for conservation measures based on the distribution and iife cycle of C.kraussi were made. The factors affecting the distribution of C.kraussi are discussed. The problem of the larval development in C.kraussi was discussed in relation to reviews of larval types of benthic invertebrates. The importance of the burrow, the possible route by which C.kraussi has invaded estuaries and the differences between open and closed estuaries as shown by the effects on C.kraussi were discussed.
- Full Text:
- Authors: Forbes, Anthony Tonks
- Date: 1974
- Subjects: Estuarine biology -- South Africa Shrimps -- South Africa Decapoda (Crustacea) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5850 , http://hdl.handle.net/10962/d1011866
- Description: The distribution of Callianassa kraussi in southern Africa extends from Lamberts Bay on the west coast to San Martinho in Mocambique. This represents a northerly extension of the range from the previous known limit of Inhaca Island. In this area 59 localities were visited and records obtained for an additional 16. Three areas were selected for detailed study. These were the west Kleinemonde estuary, which is normally closed off from the sea by a sand bar and the open Swartkops estuary both on the southeastern Cape coast, and the Swartvlei system, which consists of a lake connected to the sea by a channel which closes intermittently, on the southern Cape coast. The nature of the burrows constructed by C. kraussi was investigated in these areas. Burrow complexes may have up to nine entrances but more commonly two to four. Laboratory studies suggest that the number of entrances does not exceed the number of prawns present and consequently burrow opening counts will give an estimate of population density. Water movement can result in the closing off of burrows while strong water and sand movement will exclude C.kraussi from an area. C.kraussi is also excluded from areas which have very coarse substrates. A three year regular sampling program showed that C.kraussi breeds mainly in winter/spring with a smaller breeding peak in summer. Egg development time at 20°C in a salinity of 35° /₀₀ is 30-33 days. There are two larval stages which last 3-5 days. Development time of the eggs is tripled at temperatures of 13-15°C while larval development time is extended to 9-14 days. Development is possibly slightly accelerated at 25 ± 3°C but the number of eggs hatching is markedly reduced. Larval development times were similar to those at 20° and 35°/₀₀. There are no planktonic larval stages. Growth was more rapid and greater size was attained in the open Swartkops estuary than in the closed Kleinemonde estuary. Prawns hatching in winter/spring breed for the first time in the following summer at an age of about 16 months and then again in the following winter/spring at an age of about 2 years. Prawns hatching in summer breed in the following winter at an age of about 18 months and then again in the immediately following summer. Longevity in both sexes is about 2 years. Dispersal is accomplished by migration of the post-larval juvenile phases at an age of 3-5 months. Non-selfmaintaining populations exist in areas where salinities are too low to permit breeding. Population densities were found to vary markedly in different areas. Investigations of osmotic and ionic regulation showed that C.kraussi is a strong hyper-regulator and thus distinct from any other known species in the genus. Volume regulatory ability is well developed and depends on variable rates of urine production. Salt loss in dilutions occurs almost equally via the gills and the urine. The general responses of C.kraussi to dilutions of sea water are discussed. Various suggestions for conservation measures based on the distribution and iife cycle of C.kraussi were made. The factors affecting the distribution of C.kraussi are discussed. The problem of the larval development in C.kraussi was discussed in relation to reviews of larval types of benthic invertebrates. The importance of the burrow, the possible route by which C.kraussi has invaded estuaries and the differences between open and closed estuaries as shown by the effects on C.kraussi were discussed.
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The crystal structure of caesium permanganate by x-ray diffraction
- Authors: Nassimbeni, L R
- Date: 1963
- Subjects: Permanganates -- Crystallography , X-rays -- Diffraction , Crystals -- Piezoelectricity , Pyroelectricity
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4484 , http://hdl.handle.net/10962/d1012942
- Description: The crystal structure of caesium permanganate has been determined. CsMn0₄ crystallises in the orthorhombic space group Pnma. There are four molecules per unit cell with a = 10.0692 Å, b = 5.8080 Å, c = 7.9470 Å. The structure was determined by Fourier syntheses on the (010) and (001) projections and refined by two-dimensional difference syntheses. The structure is similar to that of KMn0₄. The manganese is surrounded by four oxygen atoms at an average distance of 1.629 Å arranged in a slightly distorted tetrahedron. The caesium is surrounded by eight manganese atoms at an average distance of 4.381 Å.
- Full Text:
- Authors: Nassimbeni, L R
- Date: 1963
- Subjects: Permanganates -- Crystallography , X-rays -- Diffraction , Crystals -- Piezoelectricity , Pyroelectricity
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4484 , http://hdl.handle.net/10962/d1012942
- Description: The crystal structure of caesium permanganate has been determined. CsMn0₄ crystallises in the orthorhombic space group Pnma. There are four molecules per unit cell with a = 10.0692 Å, b = 5.8080 Å, c = 7.9470 Å. The structure was determined by Fourier syntheses on the (010) and (001) projections and refined by two-dimensional difference syntheses. The structure is similar to that of KMn0₄. The manganese is surrounded by four oxygen atoms at an average distance of 1.629 Å arranged in a slightly distorted tetrahedron. The caesium is surrounded by eight manganese atoms at an average distance of 4.381 Å.
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A study of conditions in the upper atmosphere and their deduction from radio measurements
- Gledhill, J A, Szendrei, M E
- Authors: Gledhill, J A , Szendrei, M E
- Date: 1948
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:21181 , http://hdl.handle.net/10962/6795
- Description: Summary: In part 1 (a), after a brief historical outline of methods of ionospheric investigation and their development, the construction in this laboratory of manually operated equipment for sounding the ionosphere is described. Photographic records of good definition were taken at regular intervals over a period of four months during the summer of 1945-6. These were fully sealed for critical frequencies, true heights and thicknesses of all the layers present, and mean monthly values of these quantities for each hour are tabulated. An extensive correlation with magnetic data from Hermanus indicated good correlation between magnetic activity and disturbed ionospheric conditions. On these grounds some disturbed days were rejected, and others were eliminated on ionospheric grounds. Smoothed mean values are tabulated and graphs drawn. These are presented in concise form on "electron density maps", which are graphs showing lines of constant electron density plotted as functions of time and height. In part 1 (b), a new theory of layer-formation is developed, in which the temperature is assumed to vary linearly with height. The equations are compared at each step with those obtained by Chapman in his theory of layer-formation in an isothermal atmosphere. The equations for the maximum of electron density and its height are also given. The effect of the parameters on the shape of the layer is shown in graphical form. The equations are somewhat complex in form, but an ingenious graphical method has been devised suitable for the application of the theory to results given in the form of those in section 1 (a). From this application values are obtained for the temperature gradient, the temperature at 200 km. and its variation over the middle part of the day. The results obtained are in accordance with previous estimates, and offer numerical confirmation of the theory that the atmosphere expands bodily upwards during the middle part of a summer day.
- Full Text:
- Authors: Gledhill, J A , Szendrei, M E
- Date: 1948
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:21181 , http://hdl.handle.net/10962/6795
- Description: Summary: In part 1 (a), after a brief historical outline of methods of ionospheric investigation and their development, the construction in this laboratory of manually operated equipment for sounding the ionosphere is described. Photographic records of good definition were taken at regular intervals over a period of four months during the summer of 1945-6. These were fully sealed for critical frequencies, true heights and thicknesses of all the layers present, and mean monthly values of these quantities for each hour are tabulated. An extensive correlation with magnetic data from Hermanus indicated good correlation between magnetic activity and disturbed ionospheric conditions. On these grounds some disturbed days were rejected, and others were eliminated on ionospheric grounds. Smoothed mean values are tabulated and graphs drawn. These are presented in concise form on "electron density maps", which are graphs showing lines of constant electron density plotted as functions of time and height. In part 1 (b), a new theory of layer-formation is developed, in which the temperature is assumed to vary linearly with height. The equations are compared at each step with those obtained by Chapman in his theory of layer-formation in an isothermal atmosphere. The equations for the maximum of electron density and its height are also given. The effect of the parameters on the shape of the layer is shown in graphical form. The equations are somewhat complex in form, but an ingenious graphical method has been devised suitable for the application of the theory to results given in the form of those in section 1 (a). From this application values are obtained for the temperature gradient, the temperature at 200 km. and its variation over the middle part of the day. The results obtained are in accordance with previous estimates, and offer numerical confirmation of the theory that the atmosphere expands bodily upwards during the middle part of a summer day.
- Full Text:
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