An analysis of mathematical connections in the presentations of fraction concepts in Namibian grade 7 mathematics textbooks
- Authors: Sibeso, Pumulo Priscah
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/436488 , vital:73276
- Description: This study investigated how selected grade 11 mathematics learners used smartphones with the MathCityMap application to learn trigonometry outdoors for conceptual understanding. The aim of this research project was to explore outdoor mathematics learning for conceptual understanding using smartphones. This case study of grade 11 mathematics learners in Lejweleputswa District in the Free State Province, was informed by the Realistic Mathematics Education theory. The study is grounded within an interpretive paradigm and used the explanatory sequential mixed-method design. Forty-two grade 11 mathematics learners participated in the survey and from these 12 were purposively selected to participate in walking the mathematics trails and interviews. The findings revealed that, while the grade 11 mathematics learners acknowledged the significance and value of using smartphones for learning mathematics, they were prohibited from carrying or using smartphones on the school premises, as part of the school code of conduct. The preferred use of smartphones for learning mathematics was understandable, as the survey was conducted at a time when the COVID-19 pandemic and associated restrictions were still in place. The survey unearthed that among applications for learning mathematics, the MathCityMap application was not known by the learners who participated in the survey. Mathematics trails observations indicated that outdoor tasks were a source of mathematical concepts or formal mathematical knowledge, and enabled learners to reinvent mathematical ideas and concepts with adult guidance. Learners were able to make use of appropriate mathematical models and connections. The mathematics trails ignited robust discussions among learners, and prompted learners to draw from prior knowledge, and recognise and identify suitable mathematical models and shapes from the real-world objects. Learners were able to use multiple representations, make necessary mathematical links, and use their prior knowledge to enhance their trigonometry conceptual understanding. This study concluded that using smartphones with the MathCityMap application could enhance conceptual understanding of trigonometry. The implications for teachers are that learners should be exposed to outdoor mathematics learning using smartphones with the MathCityMap application to improve their conceptual understanding. It is hoped that the results of this study can be used by various stakeholders, who include, inter alia, mathematics subject advisors and teacher training institutions, to enhance learners’ conceptual understanding of mathematics. , Thesis (MEd) -- Faculty of Education, Secondary and Post School Education, 2024
- Full Text:
- Date Issued: 2024-04-05
- Authors: Sibeso, Pumulo Priscah
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/436488 , vital:73276
- Description: This study investigated how selected grade 11 mathematics learners used smartphones with the MathCityMap application to learn trigonometry outdoors for conceptual understanding. The aim of this research project was to explore outdoor mathematics learning for conceptual understanding using smartphones. This case study of grade 11 mathematics learners in Lejweleputswa District in the Free State Province, was informed by the Realistic Mathematics Education theory. The study is grounded within an interpretive paradigm and used the explanatory sequential mixed-method design. Forty-two grade 11 mathematics learners participated in the survey and from these 12 were purposively selected to participate in walking the mathematics trails and interviews. The findings revealed that, while the grade 11 mathematics learners acknowledged the significance and value of using smartphones for learning mathematics, they were prohibited from carrying or using smartphones on the school premises, as part of the school code of conduct. The preferred use of smartphones for learning mathematics was understandable, as the survey was conducted at a time when the COVID-19 pandemic and associated restrictions were still in place. The survey unearthed that among applications for learning mathematics, the MathCityMap application was not known by the learners who participated in the survey. Mathematics trails observations indicated that outdoor tasks were a source of mathematical concepts or formal mathematical knowledge, and enabled learners to reinvent mathematical ideas and concepts with adult guidance. Learners were able to make use of appropriate mathematical models and connections. The mathematics trails ignited robust discussions among learners, and prompted learners to draw from prior knowledge, and recognise and identify suitable mathematical models and shapes from the real-world objects. Learners were able to use multiple representations, make necessary mathematical links, and use their prior knowledge to enhance their trigonometry conceptual understanding. This study concluded that using smartphones with the MathCityMap application could enhance conceptual understanding of trigonometry. The implications for teachers are that learners should be exposed to outdoor mathematics learning using smartphones with the MathCityMap application to improve their conceptual understanding. It is hoped that the results of this study can be used by various stakeholders, who include, inter alia, mathematics subject advisors and teacher training institutions, to enhance learners’ conceptual understanding of mathematics. , Thesis (MEd) -- Faculty of Education, Secondary and Post School Education, 2024
- Full Text:
- Date Issued: 2024-04-05
Ecological impacts of photoautotrophic Euendoliths on South African mussel beds
- Dievart, Alexia Madeleine Angèle
- Authors: Dievart, Alexia Madeleine Angèle
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435650 , vital:73176 , DOI 10.21504/10962/435650
- Description: Aphytis lingnanensis was reared and tested in South Africa in the early 2000s for augmentation against red scale on citrus and was found to be ineffective. Aphytis melinus is now commercially available and it is important that the efficacy of augmentation thereof on red scale is determined locally. Field trials, fitness assessments and molecular identification on A. melinus from two insectaries were done. Field trials was done in seven, five and six pairs of comparable release and control orchards across the Eastern and Western Cape during the seasons of 2019/2020, 2020/2021 and 2021/2022 respectively. Red scale infestation was monitored and a sample of 20 infested fruit from each orchard was randomly collected every four weeks. Aphytis spp. responsible for parasitism were identified and the percentage parasitism recorded. Results of this study of field trials suggest that the augmentation of A. melinus did not significantly increase the level of parasitism above that of the untreated control. Five repetitions with six replicates of flight and longevity tests were performed with wasps from each insectary. Wasps in the longevity test from two insectaries were kept at 23 °C and 65% RH with honey. Flight tests were performed in tubes of 16 by 30 cm, with a light above a clear, sticky ceiling at 23 °C and 65% RH. On average in five replicates, 65%, 33% and 17% A. melinus wasps were alive on day one, five and 10 respectively. The overall sex ratio was 1.58 for females to males, but 1.05, 2.19 and 2.66 for non-flyers, non-crawlers, crawlers, and flyers respectively. In flight tests for both insectaries combined, only 36.97% of wasps could initiate flight in 24 h while 56.96% remained on the tube floor, and 6.05% attempted to crawl upwards. No significant differences in flight performance were recorded between the two insectaries. Wasps from the local insectary lived significantly longer during the longevity tests but were shorter in transit than wasps from the overseas insectary. COI genes were sequenced and compared against Genbank sequences using BLAST. Molecular identifications did not confirm morphological identifications for all species, indicating unexpected genetic complexity. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
- Date Issued: 2024-04-05
- Authors: Dievart, Alexia Madeleine Angèle
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435650 , vital:73176 , DOI 10.21504/10962/435650
- Description: Aphytis lingnanensis was reared and tested in South Africa in the early 2000s for augmentation against red scale on citrus and was found to be ineffective. Aphytis melinus is now commercially available and it is important that the efficacy of augmentation thereof on red scale is determined locally. Field trials, fitness assessments and molecular identification on A. melinus from two insectaries were done. Field trials was done in seven, five and six pairs of comparable release and control orchards across the Eastern and Western Cape during the seasons of 2019/2020, 2020/2021 and 2021/2022 respectively. Red scale infestation was monitored and a sample of 20 infested fruit from each orchard was randomly collected every four weeks. Aphytis spp. responsible for parasitism were identified and the percentage parasitism recorded. Results of this study of field trials suggest that the augmentation of A. melinus did not significantly increase the level of parasitism above that of the untreated control. Five repetitions with six replicates of flight and longevity tests were performed with wasps from each insectary. Wasps in the longevity test from two insectaries were kept at 23 °C and 65% RH with honey. Flight tests were performed in tubes of 16 by 30 cm, with a light above a clear, sticky ceiling at 23 °C and 65% RH. On average in five replicates, 65%, 33% and 17% A. melinus wasps were alive on day one, five and 10 respectively. The overall sex ratio was 1.58 for females to males, but 1.05, 2.19 and 2.66 for non-flyers, non-crawlers, crawlers, and flyers respectively. In flight tests for both insectaries combined, only 36.97% of wasps could initiate flight in 24 h while 56.96% remained on the tube floor, and 6.05% attempted to crawl upwards. No significant differences in flight performance were recorded between the two insectaries. Wasps from the local insectary lived significantly longer during the longevity tests but were shorter in transit than wasps from the overseas insectary. COI genes were sequenced and compared against Genbank sequences using BLAST. Molecular identifications did not confirm morphological identifications for all species, indicating unexpected genetic complexity. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
- Date Issued: 2024-04-05
Genetic connectivity of the slinger Chrysoblephus puniceus among Marine Protected Areas and unprotected areas along the east coast of South Africa
- Ockhuis, Samantha Angelique Natasha
- Authors: Ockhuis, Samantha Angelique Natasha
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435954 , vital:73215 , DOI 10.21504/10962/435954
- Description: Marine Protected Areas (MPAs) are advocated worldwide for the conservation of biodiversity and fisheries management, as well as for adaptation and resilience in the face of climate change. Their effectiveness has been noted through increases in abundances, biomass, sizes and diversity of species, as well as the recovery of overexploited fisheries. For MPAs to realise their full potential, these benefits need to expand beyond their boundaries through larval dispersal and/or adult spillover. Connectivity between MPAs is critical for planning and placement of MPAs, as this promotes the persistence of metapopulations, their recovery from disturbance, as well as productivity in marine ecosystems. The effectiveness of MPAs in conserving biodiversity along the east coast of South Africa has been established; however, limited evidence is available on whether they offer benefits beyond their boundaries, enhancing biodiversity and fisheries in adjacent areas. The slinger Chrysoblephus puniceus, an endemic southern African sparid, is a major component of the commercial linefishery in KwaZulu-Natal (KZN), South Africa and southern Mozambique, and is also caught in the recreational ski-boat fishery in these regions. The spawning of slinger occurs in shoals on offshore reefs from southern Mozambique to the north of KZN, and larvae are likely transported southwards, assisted by the southward-flowing Agulhas Current and promoted by a relatively long larval duration. Slinger are relatively resident, but occasional northward migrations have been observed. These life history characteristics suggested that slinger would be a suitable biological model to test connectivity along the east coast, and particularly connectivity between MPAs. The aim of this study was therefore to investigate connectivity of slinger between MPAs and the surrounding areas along the east coast of South Africa, using restriction-site-associated DNA (RAD) sequencing. This formed part of the larger CAPTOR project investigating east coast MPA connectivity across a range of taxa and habitat types. A temporal comparison of genetic diversity in slinger spanning two sampling events (2012 and 2018) revealed no substantial changes in genetic diversity, as well as a lack of genetic structure along the KZN coast. Similarly, no substantial changes in effective population size (Ne) were found between 2012 and 2018 for microsatellites and Single Nucleotide Polymorphisms (SNPs). However, subtle, albeit non-significant, differences were observed both spatially and over time in the microsatellite data, indicating some instability along the KZN coast. A lack of genetic structure based on RAD sequencing was observed between east coast MPAs and the surrounding areas. This implies high connectivity along the coast - not only are east coast MPAs connected, the surrounding areas are also connected, and there is replenishment between all areas via larval dispersal and/or adult spillover. Analyses of multidirectional gene flow between MPAs, together with known spatial spawning patterns and prior particle dispersal modelling, identified the Richards Bay area as a key source of recruits. However, parentage analysis – a direct method to estimate connectivity – failed to match any parent-offspring pairs in this study; successful parentage assignments are highly dependent on intensive sampling of potential parents and are seldom feasible in marine systems, as most populations have large effective population sizes. Estimates of intergenerational effective population size for slinger in this study are considered large - >2 000 and infinite based on adults and juveniles, respectively. Population genetics revealed close genetic similarities between slinger adult and juvenile slinger sites, emphasizing genetic connectivity and the lack of structure between sites observed before. This was the first study on South African sparids to use RAD sequencing to assess genetic connectivity between MPAs along the east coast of South Africa. Overall, results provide evidence that MPAs along the east coast of South Africa are connected, and can readily replenish or be replenished by other sites along the east coast of South Africa, whether they are within MPAs or not. So too are the areas surrounding MPAs interconnected, and slinger forms a homogenous single population on the east coast of South Africa. This notwithstanding, it is important that east coast MPAs, particularly those that host spawning shoals of slinger, are well managed in order that they continue to provide recruits to sustain the population and support sustainable fisheries. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2024
- Full Text:
- Date Issued: 2024-04-05
- Authors: Ockhuis, Samantha Angelique Natasha
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435954 , vital:73215 , DOI 10.21504/10962/435954
- Description: Marine Protected Areas (MPAs) are advocated worldwide for the conservation of biodiversity and fisheries management, as well as for adaptation and resilience in the face of climate change. Their effectiveness has been noted through increases in abundances, biomass, sizes and diversity of species, as well as the recovery of overexploited fisheries. For MPAs to realise their full potential, these benefits need to expand beyond their boundaries through larval dispersal and/or adult spillover. Connectivity between MPAs is critical for planning and placement of MPAs, as this promotes the persistence of metapopulations, their recovery from disturbance, as well as productivity in marine ecosystems. The effectiveness of MPAs in conserving biodiversity along the east coast of South Africa has been established; however, limited evidence is available on whether they offer benefits beyond their boundaries, enhancing biodiversity and fisheries in adjacent areas. The slinger Chrysoblephus puniceus, an endemic southern African sparid, is a major component of the commercial linefishery in KwaZulu-Natal (KZN), South Africa and southern Mozambique, and is also caught in the recreational ski-boat fishery in these regions. The spawning of slinger occurs in shoals on offshore reefs from southern Mozambique to the north of KZN, and larvae are likely transported southwards, assisted by the southward-flowing Agulhas Current and promoted by a relatively long larval duration. Slinger are relatively resident, but occasional northward migrations have been observed. These life history characteristics suggested that slinger would be a suitable biological model to test connectivity along the east coast, and particularly connectivity between MPAs. The aim of this study was therefore to investigate connectivity of slinger between MPAs and the surrounding areas along the east coast of South Africa, using restriction-site-associated DNA (RAD) sequencing. This formed part of the larger CAPTOR project investigating east coast MPA connectivity across a range of taxa and habitat types. A temporal comparison of genetic diversity in slinger spanning two sampling events (2012 and 2018) revealed no substantial changes in genetic diversity, as well as a lack of genetic structure along the KZN coast. Similarly, no substantial changes in effective population size (Ne) were found between 2012 and 2018 for microsatellites and Single Nucleotide Polymorphisms (SNPs). However, subtle, albeit non-significant, differences were observed both spatially and over time in the microsatellite data, indicating some instability along the KZN coast. A lack of genetic structure based on RAD sequencing was observed between east coast MPAs and the surrounding areas. This implies high connectivity along the coast - not only are east coast MPAs connected, the surrounding areas are also connected, and there is replenishment between all areas via larval dispersal and/or adult spillover. Analyses of multidirectional gene flow between MPAs, together with known spatial spawning patterns and prior particle dispersal modelling, identified the Richards Bay area as a key source of recruits. However, parentage analysis – a direct method to estimate connectivity – failed to match any parent-offspring pairs in this study; successful parentage assignments are highly dependent on intensive sampling of potential parents and are seldom feasible in marine systems, as most populations have large effective population sizes. Estimates of intergenerational effective population size for slinger in this study are considered large - >2 000 and infinite based on adults and juveniles, respectively. Population genetics revealed close genetic similarities between slinger adult and juvenile slinger sites, emphasizing genetic connectivity and the lack of structure between sites observed before. This was the first study on South African sparids to use RAD sequencing to assess genetic connectivity between MPAs along the east coast of South Africa. Overall, results provide evidence that MPAs along the east coast of South Africa are connected, and can readily replenish or be replenished by other sites along the east coast of South Africa, whether they are within MPAs or not. So too are the areas surrounding MPAs interconnected, and slinger forms a homogenous single population on the east coast of South Africa. This notwithstanding, it is important that east coast MPAs, particularly those that host spawning shoals of slinger, are well managed in order that they continue to provide recruits to sustain the population and support sustainable fisheries. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2024
- Full Text:
- Date Issued: 2024-04-05
Identification of Mycobacterium tuberculosis DnaK substrates – towards inhibiting DnaK as a novel drug target for the treatment of tuberculosis
- Authors: Tonui, Ronald
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435975 , vital:73217
- Description: Access restricted. Expected release in 2026. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2024
- Full Text:
- Date Issued: 2024-04-05
- Authors: Tonui, Ronald
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435975 , vital:73217
- Description: Access restricted. Expected release in 2026. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2024
- Full Text:
- Date Issued: 2024-04-05
Ingqiqo yamanina kuxanduva lokusiphula neengcambu ugonyamelo nokuxhatshazwa: Uhlalutyo lweetekisi ZesiXhosa ezicatshulwe kuncwadi olubhalwe ngamanina (1976-2015)
- Authors: Bilatyi, Katy Nomthandazo
- Date: 2024-04-04
- Subjects: Uncatalogued
- Language: Xhosa
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435582 , vital:73170 , DOI 10.21504/10962/435582
- Description: Uphando luza kuqwalasela ingqiqo yamanina kuxanduva lokusiphula neengcambu ugonyamelo nokuxhatshazwa kwawo ngamadoda. Ingxoxo iza kugxila kubabhali abangamanina beencwadi zesiXhosa ezicatshulweyo kolu phando, nalapho kuqwalaselwa indlela ababazoba ngayo abalinganiswa babo abangamanina. Kule ngxoxo kuqwalaselwa indlela ababhali abangamanina abafana noBelebesi (1976), Dazela (1988), Magadla (1992) Madolo (1998), Mayosi (2003), Magqashela (2006) kunye noBuzani (2015) abathe babazoba ngayo abalinganiswa abangamanina kwiincwadi zesiXhosa ezicatshuliweyo. Oku kukutyhila ubukrelekrele bababhali ekusebenziseni uncwadi ukuzisa izisombululo kwimingeni ajamelene nayo amanina efana nogonyamelo kunye noxhatshwazo. Obu bukrelekrele baba babhali bujongwa ngokweembali ezimbini, imbali yaphambi kozuzo lwenkululeko emva kongenelelo lobuKoloniyali kunye neyasemva kozuzo lwenkululeko yaseMzantsi Afrika. Iincwadi ezikhethiweyo zibhalwe phakathi kweminyaka ye-1976 ukuya kwiminyaka yama-2015. Uphando luya kujonga ukuba lungaba lukhona utshintsho kusini na kwindlela la manina ababazoba ngayo abalinganiswa ngokwezi mbali zahlukileyo kananjalo naxa bezotywa ngababhali abangamadoda. Uphando luya kutyhila kananjalo imixholo nemixholwana abayikhethayo nedlulisa iimvakalelo zabo bengamanina kumbandela wogonyamelo olukhatshwa yipatriyakhi kunye noxhatshazo abalufumana kumadoda. Xa kuphendlwa le mixholo yaba babhali bahlukileyo baneemvelaphi ezahlukileyo ngokwemontlalo bebhala ngokwamaxesha okanye iimbhali ezahlukileyo, kuya kucaca ukuba amava abo ayafana nokuba linina okanye ibhinqa. Loo mava abo anele ukuba bajikeleze kwimixholo ebizwa ngokuba yifeminist themes nakubeni izimbo zabo zokubhala zahlukile nje. Injongo kukubonisa ukuba nangona amanina aphila phantsi kweemeko neemontlalo ezahlukileyo nje, iinzima neentlungu zawo azisombulula ngendlela efanayo ngokusebenzisa usiba. Le ngxoxo ikhatshwa ziithiyori ezifana nefemayinizimu, ngakumbi ifemayinizimu yaseAfrika kunye kunye nangokoMzantsi Afrika iquka iMotherism kunye nenkcubeko ephehlelelwe phantsi kwePatriyakhi. Ezi thiyori ziludondolo lokuphendla nokuhlalutya ezi ncwadi zikhethiweyo zesiXhosa ukuze sicacelwe yeyona ndima idlalwa ngamanina kuluntu nanjengoko sisazi ukuba apha eMzantsi Afrika adlale eyona ndima yokuncedisa ekuziseni utshintsho kwimibandela yengcinezelo nasekuzuzweni kwenkululeko. Yiyo loo nto kufuneka nawo abonakale exhamla ngokulinganayo namadoda kwinkululeko ayisebenzeleyo ngokususa ugonyamelo, uxhatshazo nokubulawa kwawo ngamadoda. , Thesis (PhD) -- Humanities, School of Languages and Literatures, 2024
- Full Text:
- Date Issued: 2024-04-04
- Authors: Bilatyi, Katy Nomthandazo
- Date: 2024-04-04
- Subjects: Uncatalogued
- Language: Xhosa
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435582 , vital:73170 , DOI 10.21504/10962/435582
- Description: Uphando luza kuqwalasela ingqiqo yamanina kuxanduva lokusiphula neengcambu ugonyamelo nokuxhatshazwa kwawo ngamadoda. Ingxoxo iza kugxila kubabhali abangamanina beencwadi zesiXhosa ezicatshulweyo kolu phando, nalapho kuqwalaselwa indlela ababazoba ngayo abalinganiswa babo abangamanina. Kule ngxoxo kuqwalaselwa indlela ababhali abangamanina abafana noBelebesi (1976), Dazela (1988), Magadla (1992) Madolo (1998), Mayosi (2003), Magqashela (2006) kunye noBuzani (2015) abathe babazoba ngayo abalinganiswa abangamanina kwiincwadi zesiXhosa ezicatshuliweyo. Oku kukutyhila ubukrelekrele bababhali ekusebenziseni uncwadi ukuzisa izisombululo kwimingeni ajamelene nayo amanina efana nogonyamelo kunye noxhatshwazo. Obu bukrelekrele baba babhali bujongwa ngokweembali ezimbini, imbali yaphambi kozuzo lwenkululeko emva kongenelelo lobuKoloniyali kunye neyasemva kozuzo lwenkululeko yaseMzantsi Afrika. Iincwadi ezikhethiweyo zibhalwe phakathi kweminyaka ye-1976 ukuya kwiminyaka yama-2015. Uphando luya kujonga ukuba lungaba lukhona utshintsho kusini na kwindlela la manina ababazoba ngayo abalinganiswa ngokwezi mbali zahlukileyo kananjalo naxa bezotywa ngababhali abangamadoda. Uphando luya kutyhila kananjalo imixholo nemixholwana abayikhethayo nedlulisa iimvakalelo zabo bengamanina kumbandela wogonyamelo olukhatshwa yipatriyakhi kunye noxhatshazo abalufumana kumadoda. Xa kuphendlwa le mixholo yaba babhali bahlukileyo baneemvelaphi ezahlukileyo ngokwemontlalo bebhala ngokwamaxesha okanye iimbhali ezahlukileyo, kuya kucaca ukuba amava abo ayafana nokuba linina okanye ibhinqa. Loo mava abo anele ukuba bajikeleze kwimixholo ebizwa ngokuba yifeminist themes nakubeni izimbo zabo zokubhala zahlukile nje. Injongo kukubonisa ukuba nangona amanina aphila phantsi kweemeko neemontlalo ezahlukileyo nje, iinzima neentlungu zawo azisombulula ngendlela efanayo ngokusebenzisa usiba. Le ngxoxo ikhatshwa ziithiyori ezifana nefemayinizimu, ngakumbi ifemayinizimu yaseAfrika kunye kunye nangokoMzantsi Afrika iquka iMotherism kunye nenkcubeko ephehlelelwe phantsi kwePatriyakhi. Ezi thiyori ziludondolo lokuphendla nokuhlalutya ezi ncwadi zikhethiweyo zesiXhosa ukuze sicacelwe yeyona ndima idlalwa ngamanina kuluntu nanjengoko sisazi ukuba apha eMzantsi Afrika adlale eyona ndima yokuncedisa ekuziseni utshintsho kwimibandela yengcinezelo nasekuzuzweni kwenkululeko. Yiyo loo nto kufuneka nawo abonakale exhamla ngokulinganayo namadoda kwinkululeko ayisebenzeleyo ngokususa ugonyamelo, uxhatshazo nokubulawa kwawo ngamadoda. , Thesis (PhD) -- Humanities, School of Languages and Literatures, 2024
- Full Text:
- Date Issued: 2024-04-04
The impact of influencer characteristics on parasocial relationships and purchase intentions
- Ngobeni, Marina Precious Sibongile
- Authors: Ngobeni, Marina Precious Sibongile
- Date: 2024-04-03
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/434734 , vital:73100
- Description: Access restricted. Expected release in 2026. , Thesis (MCom) -- Faculty of Commerce, Management, 2024
- Full Text:
- Date Issued: 2024-04-03
- Authors: Ngobeni, Marina Precious Sibongile
- Date: 2024-04-03
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/434734 , vital:73100
- Description: Access restricted. Expected release in 2026. , Thesis (MCom) -- Faculty of Commerce, Management, 2024
- Full Text:
- Date Issued: 2024-04-03
The influence of electronic-consumer experience (e-CX) on consumer post-purchase outcomes of South African e-commerce retail organisations
- Authors: Williams, Alyssa Shawntay
- Date: 2024-04-03
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/434828 , vital:73108
- Description: Access restricted. Expected release in 2026. , Thesis (PhD) -- Faculty of Commerce, Management, 2024
- Full Text:
- Date Issued: 2024-04-03
- Authors: Williams, Alyssa Shawntay
- Date: 2024-04-03
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/434828 , vital:73108
- Description: Access restricted. Expected release in 2026. , Thesis (PhD) -- Faculty of Commerce, Management, 2024
- Full Text:
- Date Issued: 2024-04-03
Technological Pedagogical Content Knowledge (TPACK): investigating senior primary mathematics teachers’ integration of technology in the classroom in Okahao educational circuit
- Shikesho, Hilya Ndahambelela
- Authors: Shikesho, Hilya Ndahambelela
- Date: 2024-04
- Subjects: Technological Pedagogical Content Knowledge , Cultural-historical activity theory , Educational technology , Mathematics Study and teaching (Primary) Namibia Okahao , Mediated learning experience , Social interaction
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/423913 , vital:72104
- Description: The overwhelming advancement of ICT devices in the contemporary Namibian education system has led to their praise for supporting differentiated instruction, fostering collaboration, and engaging multiple intelligences in teaching and learning. Consequently, the compulsory incorporation of ICTs into the teaching and learning process becomes imperative across various fields of study, including Mathematics. However, the integration of technology-based teaching proves to be a complex and challenging issue, often considered a wicked problem. To explore this matter, a qualitative case study was conducted to investigate how Senior Primary Mathematics Teachers integrated technology to develop their TPACK. The study was conducted among the twenty-seven senior primary mathematics teachers in the Okahao educational circuit in the Omuasti region. The study utilized Vygotsky‘s (1978); Socio-cultural Theory, together with Mishra and Koehler (2006), and; the Technological Pedagogical Content Knowledge (TPACK) framework was used as a lens to analyse the data. The data were gathered through semi-structured questionnaires, semi-structured interviews, focus group interviews, and lesson observations. The study findings indicate that senior primary mathematics teachers utilize the available resources at their respective schools during their classroom instruction. The study further reveals that mathematics teachers exhibit a positive attitude toward the integration of technology. The study uncovers the intricate interplay between technological knowledge, pedagogical expertise, and content knowledge within the context of mathematics education. The findings reveal that while participants demonstrate a high level of proficiency in certain TPACK components such as CK, TK, PK, TPK, and PCK, they expressed a moderate level of expertise in TCK and TPCK. The study also identified challenges in TPACK development, particularly the need for subject specific technology training, lack of technological infrastructure, particularly advanced technology, as well as a deficiency in ICT knowledge. The importance of access to various technologies was emphasized, enabling teachers to seamlessly integrate technology into their practices and address diverse learning styles. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Shikesho, Hilya Ndahambelela
- Date: 2024-04
- Subjects: Technological Pedagogical Content Knowledge , Cultural-historical activity theory , Educational technology , Mathematics Study and teaching (Primary) Namibia Okahao , Mediated learning experience , Social interaction
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/423913 , vital:72104
- Description: The overwhelming advancement of ICT devices in the contemporary Namibian education system has led to their praise for supporting differentiated instruction, fostering collaboration, and engaging multiple intelligences in teaching and learning. Consequently, the compulsory incorporation of ICTs into the teaching and learning process becomes imperative across various fields of study, including Mathematics. However, the integration of technology-based teaching proves to be a complex and challenging issue, often considered a wicked problem. To explore this matter, a qualitative case study was conducted to investigate how Senior Primary Mathematics Teachers integrated technology to develop their TPACK. The study was conducted among the twenty-seven senior primary mathematics teachers in the Okahao educational circuit in the Omuasti region. The study utilized Vygotsky‘s (1978); Socio-cultural Theory, together with Mishra and Koehler (2006), and; the Technological Pedagogical Content Knowledge (TPACK) framework was used as a lens to analyse the data. The data were gathered through semi-structured questionnaires, semi-structured interviews, focus group interviews, and lesson observations. The study findings indicate that senior primary mathematics teachers utilize the available resources at their respective schools during their classroom instruction. The study further reveals that mathematics teachers exhibit a positive attitude toward the integration of technology. The study uncovers the intricate interplay between technological knowledge, pedagogical expertise, and content knowledge within the context of mathematics education. The findings reveal that while participants demonstrate a high level of proficiency in certain TPACK components such as CK, TK, PK, TPK, and PCK, they expressed a moderate level of expertise in TCK and TPCK. The study also identified challenges in TPACK development, particularly the need for subject specific technology training, lack of technological infrastructure, particularly advanced technology, as well as a deficiency in ICT knowledge. The importance of access to various technologies was emphasized, enabling teachers to seamlessly integrate technology into their practices and address diverse learning styles. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-04
Exploring the social construction of masculine identity as it relates to rape in the Buffalo City Municipality
- Matshikwe, Noluthando https://orcid.org/0000-0003-0439-0766
- Authors: Matshikwe, Noluthando https://orcid.org/0000-0003-0439-0766
- Date: 2024-01
- Subjects: Masculinity , Gender identity , Sex role
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28595 , vital:74454
- Description: In South Africa, rape is a pandemic that is persistent and pervasive in unprecedented amounts. The construction of masculinity is understood to be a contributing factor to the rape pandemic in the country, as its construction focuses on power, dominance, and control of the less masculine individual. This study explored the social construction of masculine identity related to rape in the Buffalo City Municipality. The study sample consisted of a mixed-gendered focus group interview of eight participants (four males and four females). In addition, the study utilised six individual virtual interviews (three males and three females) who were all students at a local university. When analysing the data received from the participants, the study adopted Willig’s six stages of Foucauldian discourse analysis outlined in her book “Introducing Qualitative Research in Psychology” (2008, p. 118). The Foucauldian discourse analysis utilised in this study allowed for answering research questions through direct analysis of the extracts selected for this study. The results of this study indicated that masculinity is a socially constructed phenomenon synonymous with dominance and power. Hegemonic masculinity was constructed as synonymous with manhood, resulting in an individual being entitled to social privileges. Subordinate subjects were constructed as vulnerable to the expression of these qualities by being dominated, controlled, and raped. This construction of masculinity continues to construct robust and powerless subjects, where the powerless subject is subjected to the hegemonic male power, dominance, and control, creating an imbalance of social power and an unjust social hierarchy of. The construction of masculinity is linked with the rape pandemic faced by the country, as it constructs hegemonic forms of masculinity associated with domination and violation of other members of society, through sexual assault. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2024
- Full Text:
- Date Issued: 2024-01
- Authors: Matshikwe, Noluthando https://orcid.org/0000-0003-0439-0766
- Date: 2024-01
- Subjects: Masculinity , Gender identity , Sex role
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28595 , vital:74454
- Description: In South Africa, rape is a pandemic that is persistent and pervasive in unprecedented amounts. The construction of masculinity is understood to be a contributing factor to the rape pandemic in the country, as its construction focuses on power, dominance, and control of the less masculine individual. This study explored the social construction of masculine identity related to rape in the Buffalo City Municipality. The study sample consisted of a mixed-gendered focus group interview of eight participants (four males and four females). In addition, the study utilised six individual virtual interviews (three males and three females) who were all students at a local university. When analysing the data received from the participants, the study adopted Willig’s six stages of Foucauldian discourse analysis outlined in her book “Introducing Qualitative Research in Psychology” (2008, p. 118). The Foucauldian discourse analysis utilised in this study allowed for answering research questions through direct analysis of the extracts selected for this study. The results of this study indicated that masculinity is a socially constructed phenomenon synonymous with dominance and power. Hegemonic masculinity was constructed as synonymous with manhood, resulting in an individual being entitled to social privileges. Subordinate subjects were constructed as vulnerable to the expression of these qualities by being dominated, controlled, and raped. This construction of masculinity continues to construct robust and powerless subjects, where the powerless subject is subjected to the hegemonic male power, dominance, and control, creating an imbalance of social power and an unjust social hierarchy of. The construction of masculinity is linked with the rape pandemic faced by the country, as it constructs hegemonic forms of masculinity associated with domination and violation of other members of society, through sexual assault. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2024
- Full Text:
- Date Issued: 2024-01
Implementation of the national diploma in tourism and hospitality management curriculum in two polytechnic colleges in Zimbabwe
- Ngwenya, Khanyisani https://orcid.org/0000-0002-0543-4671
- Authors: Ngwenya, Khanyisani https://orcid.org/0000-0002-0543-4671
- Date: 2024-01
- Subjects: Hospitality industry -- Vocational guidance , Tourism -- Vocational guidance
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/28287 , vital:74165
- Description: Many countries in the world consider the tourism and hospitality industry as the leading employer with huge impact on economic growth. It has significantly contributed to their national Gross Domestic Product (GDP). Several studies conducted world over affirm that tourism contributes above the global average of ten percent. In Zimbabwe, the estimated percentage has also been as high as 10percent. The Tourism and Hospitality Management (THM) program aims to equip youth with critical industry-specific skills and mitigate unemployment. Despite this, literature has revealed that certain graduates struggle to secure industry positions due to a discrepancy between acquired skills and employer expectations. Consequently, some graduates accept menial roles outside the tourism sector, while the industry itself resorts to employing unqualified personnel. The reason lies in ineffective curriculum implementation approaches characterized by a lack of appropriate pedagogical methods. Identifying and implementing effective strategies ensures that graduates possess the requisite skills and competencies demanded by the industry, making their employability much easier. This study used a qualitative approach because of its exploratory, descriptive, and contextual nature. The interpretive paradigm provided participants’ views, opinions, and thoughts on the THM curriculum implementation. The multiple case study research design allowed ample freedom to dig deeper into rich empirical data by examining contemporary trends in implementing the ND3 in THM curriculum at two polytechnic colleges. Non-probability convenience sampling was used to select the two polytechnic colleges. Purposive sampling was used to select twelve (12) students, six (6) lecturers, and two (2) ITTD inspectors. Lecturers and inspectors were interviewed. Data from students was obtained through Focus group discussions. Curriculum documents were reviewed to provide true realities of the THM curriculum implementation. Content analysis was used to analyse data. Rogan and Grayson (2003) curriculum implementation theoretical framework guided the study. The study revealed that lecturers were dissatisfied due to inappropriate pedagogical strategies. A new model to bridge the theory/ practice gap in teaching was developed. The study recommended the adoption of a new and modern teaching model and fix the recruitment process by employing qualified lecturers to teach ND3 in THM students. , Thesis (PhD) -- Faculty of Education, 2024
- Full Text:
- Date Issued: 2024-01
- Authors: Ngwenya, Khanyisani https://orcid.org/0000-0002-0543-4671
- Date: 2024-01
- Subjects: Hospitality industry -- Vocational guidance , Tourism -- Vocational guidance
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/28287 , vital:74165
- Description: Many countries in the world consider the tourism and hospitality industry as the leading employer with huge impact on economic growth. It has significantly contributed to their national Gross Domestic Product (GDP). Several studies conducted world over affirm that tourism contributes above the global average of ten percent. In Zimbabwe, the estimated percentage has also been as high as 10percent. The Tourism and Hospitality Management (THM) program aims to equip youth with critical industry-specific skills and mitigate unemployment. Despite this, literature has revealed that certain graduates struggle to secure industry positions due to a discrepancy between acquired skills and employer expectations. Consequently, some graduates accept menial roles outside the tourism sector, while the industry itself resorts to employing unqualified personnel. The reason lies in ineffective curriculum implementation approaches characterized by a lack of appropriate pedagogical methods. Identifying and implementing effective strategies ensures that graduates possess the requisite skills and competencies demanded by the industry, making their employability much easier. This study used a qualitative approach because of its exploratory, descriptive, and contextual nature. The interpretive paradigm provided participants’ views, opinions, and thoughts on the THM curriculum implementation. The multiple case study research design allowed ample freedom to dig deeper into rich empirical data by examining contemporary trends in implementing the ND3 in THM curriculum at two polytechnic colleges. Non-probability convenience sampling was used to select the two polytechnic colleges. Purposive sampling was used to select twelve (12) students, six (6) lecturers, and two (2) ITTD inspectors. Lecturers and inspectors were interviewed. Data from students was obtained through Focus group discussions. Curriculum documents were reviewed to provide true realities of the THM curriculum implementation. Content analysis was used to analyse data. Rogan and Grayson (2003) curriculum implementation theoretical framework guided the study. The study revealed that lecturers were dissatisfied due to inappropriate pedagogical strategies. A new model to bridge the theory/ practice gap in teaching was developed. The study recommended the adoption of a new and modern teaching model and fix the recruitment process by employing qualified lecturers to teach ND3 in THM students. , Thesis (PhD) -- Faculty of Education, 2024
- Full Text:
- Date Issued: 2024-01
Rationalisation of magisterial districts to transform the judiciary and widen access to justice under the RSA constitution of 1996
- Authors: Skosana, Jacob
- Date: 2024-01
- Subjects: Justice, Administration of , Law and socialism , Human rights -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/28162 , vital:72777
- Description: The study examines how pre-1994 magisterial districts jurisdictions denied access to justice to many South Africans, and ongoing efforts to reverse this injustice. Delayed rationalisation of the judiciary and reform of the courts territorial jurisdiction during the apartheid era exacerbated the problem. The courts administered justice along spatial racial divide, and given the location of the courts, many black communities had to commute long distances to access justice and at a great cost and inconvenience. The Constitution of South Africa of 1996 provides not only for the right to equality before the law and equal protection and benefit of the law but also the right to access the courts and seek recourse. In a period spanning eight years from December 2014, new magisterial districts were proclaimed in all the nine provinces of South Africa. Despite this milestone and the imperative of the 1996 Constitution, the rationalisation process is still in its infancy: old legislation and judicial structures remain intact; divisions of the High Court continue to exercise jurisdictions determined for the pre-1994 constitutional dispensation. The status quo continues to perpetuate the denial of access to justice to communities especially those living in areas that hitherto formed part of the former homelands and self-governing ‘states’. The study was conducted through a desktop survey of primary and secondary material relevant to the rationalisation process. It drew lessons from the re-demarcation of municipal boundaries which, like magisterial districts, were based on racial laws and policies of the past. It also contrasted rationalisation principles in comparable jurisdictions. The findings provide a useful contribution to the ongoing effort to effect rationalisation of the court system. They also contribute to knowledge and enriches our understanding of the relationship that underpins the administration of justice in a dispensation driven by democratic, human rights and constitutional ethos. , Thesis (PhD (LLD)) -- Faculty of Law, 2024
- Full Text:
- Date Issued: 2024-01
- Authors: Skosana, Jacob
- Date: 2024-01
- Subjects: Justice, Administration of , Law and socialism , Human rights -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/28162 , vital:72777
- Description: The study examines how pre-1994 magisterial districts jurisdictions denied access to justice to many South Africans, and ongoing efforts to reverse this injustice. Delayed rationalisation of the judiciary and reform of the courts territorial jurisdiction during the apartheid era exacerbated the problem. The courts administered justice along spatial racial divide, and given the location of the courts, many black communities had to commute long distances to access justice and at a great cost and inconvenience. The Constitution of South Africa of 1996 provides not only for the right to equality before the law and equal protection and benefit of the law but also the right to access the courts and seek recourse. In a period spanning eight years from December 2014, new magisterial districts were proclaimed in all the nine provinces of South Africa. Despite this milestone and the imperative of the 1996 Constitution, the rationalisation process is still in its infancy: old legislation and judicial structures remain intact; divisions of the High Court continue to exercise jurisdictions determined for the pre-1994 constitutional dispensation. The status quo continues to perpetuate the denial of access to justice to communities especially those living in areas that hitherto formed part of the former homelands and self-governing ‘states’. The study was conducted through a desktop survey of primary and secondary material relevant to the rationalisation process. It drew lessons from the re-demarcation of municipal boundaries which, like magisterial districts, were based on racial laws and policies of the past. It also contrasted rationalisation principles in comparable jurisdictions. The findings provide a useful contribution to the ongoing effort to effect rationalisation of the court system. They also contribute to knowledge and enriches our understanding of the relationship that underpins the administration of justice in a dispensation driven by democratic, human rights and constitutional ethos. , Thesis (PhD (LLD)) -- Faculty of Law, 2024
- Full Text:
- Date Issued: 2024-01
The depositional history and evaluation of two late quaternary, diamondiferous pocket beaches, south-western Namibia
- Authors: Milad, Micael George
- Date: 2004-03
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/420934 , vital:71795
- Description: The two Late Quaternary, diamondiferous pocket beach deposits studied here are situated along a 10 km stretch of the storm-dominated, Atlantic coastline of the Sperrgebiet, south-western Namibia. The pocket beaches are approximately 130 km north of the Orange River mouth, which is widely accepted as a long-lived point source for diamonds sourced from the interior of southern Africa. A total of fourteen pocket beach deposits were recently evaluated in this area, but only two of these, namely Site 2 (to the south) and Site 3 (to the north), are considered here. The main diamondbearing horizons are beach gravels, which occur within, and form part of, the pocket beach sequences. The beach gravels are mostly blanketed by sand overburden, meaning that exposures available for study were limited, and much reliance was placed on borehole logging and observations of evaluation sample tailings. The main aims are to unravel the depositional history of the pocket beach sequences, identify the controls on diamond mineralisation in the beach gravels, and critically examine two different methods of estimating average diamond size for the deposits. In pursuit of these aims, sedimentological characteristics of the unconsolidated pocket beach deposits were recorded using small diameter drill holes, hydraulic grab bulk samples, trench exposures and surface outcrops. The surface geology, geomorphology and modern wave patterns were mapped using high-resolution, Airborne Laser Survey imagery coupled with extensive field checking. Three-dimensional geological modeling software was used to gain insight into the subsurface morphology of the deposits. Fossil shell samples were used to aid interpretation of ancient depositional environments and to date parts of the pocket beach sequences. Variations in diamond concentration and the size of diamonds were recorded using bulk samples, some of which were taken from a trench, but most of which were excavated using a hydraulic grab tool called the GB50. Finally, by using diamond size data from Site 3, sample data from diamondiferous beach gravels to the south of the study area and sample campaign simulations, two alternative methods of evaluating average diamond size in marine gravel deposits were appraised.The pocket beach sequences occur within north-south trending valleys of a major deflation basin and are separated from one another by rocky headlands. The ridge-and-valley topography of the deflation basin has resulted from differential erosion of Late Proterozoic basement rock units, alternating layers of which differ greatly in their resistance to the long-lived, local denudationalprocesses. On the basis of the stratigraphic information collected from the unconsolidated pocket beach valley fills, interpreted within the context of global, Late Pleistocene sea level records, the following depositional history is deduced : a) Deposition of sheetflood gravels by ephemeral streams, activated during a regressive phase. b) Transgression, culminating in the deposition of a gravel beach, representing a sea level highstand of +4 metres above mean sea level (mamsl) at between 120 000 and 130 000 BP. c)A regressive phase, resulting in deflation of former valley fills to the bedrock valley floor and accompanied by re-activation of ephemeral stream activity to form sheetflood deposits; this represents a protracted period of subaerial exposure of the +4 m gravel beach deposit. d) Deposition of a great volume of sediment in the valleys during the latter stages of the transgression from the Last Glacial Maximum (LGM). The sequence generated during this phase, which started at ca. 9 000 BP, contains : i) pan/coastal sabkha sediments, ii) shallow, sheltered bay sediments, iii) back-barrier lagoonal sediments, iv) a gravel beach deposit representing a sea level stillstand at -5 mamsl, laid down between 7 600 and 5 600 BP, v) another gravel beach deposit representing the well-known Middle Holocene sea level highstand at +2 to +3 mamsl, laid down at ca. 5 000 BP, and which terminated the transgression from the LGM. e) A minor regression to the current sea level, accompanied by progradation of the shoreline to its current position. This progradational marine unit consists almost entirely of sand and grit, reflecting the lack of gravel supply to this part of the coastline in the most recent past. f) Deposition of modern coastal dunes, which cap the pocket beach sequence and are the youngest sediments in the study area. Using trench and hydraulic grab evaluation sample results, in combination with analysis of wave patterns and field observations, the following local controls on the density distribution (ie. concentration) and size distribution of diamonds in the gravel beach deposits (+4, -5 and +2 to +3 mamsl stands) are recognised: a) Gravel beach depositional processes, which are responsible for clast sorting on the beach, have influenced the density and size distribution of diamonds. The infill zone, or beach toe, favours maximum diamond concentration while diamond size decreases from the imbricate zone (intertidal) to the infill zone (subtidal). b) Wave energy is identified as the dominant local control on diamond size distribution, but has also influenced diamond concentration to a limited degree. Larger diamonds are intimately associated with coarser beach gravels, both of which are a reflection of increased wave energy. Higher concentrations of diamonds are sometimes associated with zones of coarser gravel and therefore greater wave energy. c) The time of deposition of the host gravel beach is seen to be the dominant controlling factor with respect to diamond concentration. This is seen as evidence of significant temporal variation in the availability of diamonds in the littoral evironment. A significant reduction (20%) in average diamond size from Site 2 to Site 3, over a distance of only 6 km, is evident. The following were identified as reasons for this reduction in diamond size : a) Longshore sorting processes, of which the long-lived northerly littoral drift is a key part, are known to have played a role in the diminution of diamond size northwards from the Orange River mouth point source. However, it is believed that this can only partly account for the observed 20% reduction in diamond size. b) Input of sediment and smaller diamonds at Site 3, reworked out of an older, Eocene-aged marine succession in the hinterland, is recognised as a possible additional reason for the large reduction in diamond size from Site 2 to Site 3. It is also speculated that the large size of the pocket beach at Site 3, relative to Site 2, may have resulted in lower average wave energy at Site 3, with consequent reduced average diamond size. Diamond size in the beach gravels of Site 3, as well as in beach gravels elsewhere in the Sperrgebiet, is seen to be lognormally-distributed within geologically homogeneous zones. In theory, lognormal mean estimators represent the best method of estimating average diamond size in such cases, whereas the arithmetic mean estimator has the tendency to overestimate when large outlier values occur. Lognormal mean estimators have the added benefit of providing for the calculation of confidence limits, which are becoming increasingly more important as financial lending institutions insist on better quantification of the risk involved in resource estimates. Sample campaign simulations demonstrate, for the kinds of diamond size-frequency distributions typical of beach gravel deposits at Site 3, that there is no significant improvement in the accuracy of average diamond size estimates when lognormal mean estimators are used instead of the arithmetic mean estimator. This is because the variance (a ) of the diamond populations is low, and large outlier values are extremely unlikely to occur. However, simulation of a diamond population with high variance, drawn from a sample of beach gravels near the Orange River mouth, shows that lognormal estimators produce significantly more accurate results when a is large. Since individual diamond weights were not recorded during evaluation sampling of Site 3, numerical solution of lognormal estimators is not possible, and these would need to be solved using a less accurate graphical method. It is therefore recommended that individual diamond weights are recorded in future sampling campaigns, allowing for the use of lognormal mean estimators, and the calculation of confidence limits for average diamond size estimates. , Thesis (MSc) -- Science, Geology, 2004
- Full Text:
- Date Issued: 2004-03
- Authors: Milad, Micael George
- Date: 2004-03
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/420934 , vital:71795
- Description: The two Late Quaternary, diamondiferous pocket beach deposits studied here are situated along a 10 km stretch of the storm-dominated, Atlantic coastline of the Sperrgebiet, south-western Namibia. The pocket beaches are approximately 130 km north of the Orange River mouth, which is widely accepted as a long-lived point source for diamonds sourced from the interior of southern Africa. A total of fourteen pocket beach deposits were recently evaluated in this area, but only two of these, namely Site 2 (to the south) and Site 3 (to the north), are considered here. The main diamondbearing horizons are beach gravels, which occur within, and form part of, the pocket beach sequences. The beach gravels are mostly blanketed by sand overburden, meaning that exposures available for study were limited, and much reliance was placed on borehole logging and observations of evaluation sample tailings. The main aims are to unravel the depositional history of the pocket beach sequences, identify the controls on diamond mineralisation in the beach gravels, and critically examine two different methods of estimating average diamond size for the deposits. In pursuit of these aims, sedimentological characteristics of the unconsolidated pocket beach deposits were recorded using small diameter drill holes, hydraulic grab bulk samples, trench exposures and surface outcrops. The surface geology, geomorphology and modern wave patterns were mapped using high-resolution, Airborne Laser Survey imagery coupled with extensive field checking. Three-dimensional geological modeling software was used to gain insight into the subsurface morphology of the deposits. Fossil shell samples were used to aid interpretation of ancient depositional environments and to date parts of the pocket beach sequences. Variations in diamond concentration and the size of diamonds were recorded using bulk samples, some of which were taken from a trench, but most of which were excavated using a hydraulic grab tool called the GB50. Finally, by using diamond size data from Site 3, sample data from diamondiferous beach gravels to the south of the study area and sample campaign simulations, two alternative methods of evaluating average diamond size in marine gravel deposits were appraised.The pocket beach sequences occur within north-south trending valleys of a major deflation basin and are separated from one another by rocky headlands. The ridge-and-valley topography of the deflation basin has resulted from differential erosion of Late Proterozoic basement rock units, alternating layers of which differ greatly in their resistance to the long-lived, local denudationalprocesses. On the basis of the stratigraphic information collected from the unconsolidated pocket beach valley fills, interpreted within the context of global, Late Pleistocene sea level records, the following depositional history is deduced : a) Deposition of sheetflood gravels by ephemeral streams, activated during a regressive phase. b) Transgression, culminating in the deposition of a gravel beach, representing a sea level highstand of +4 metres above mean sea level (mamsl) at between 120 000 and 130 000 BP. c)A regressive phase, resulting in deflation of former valley fills to the bedrock valley floor and accompanied by re-activation of ephemeral stream activity to form sheetflood deposits; this represents a protracted period of subaerial exposure of the +4 m gravel beach deposit. d) Deposition of a great volume of sediment in the valleys during the latter stages of the transgression from the Last Glacial Maximum (LGM). The sequence generated during this phase, which started at ca. 9 000 BP, contains : i) pan/coastal sabkha sediments, ii) shallow, sheltered bay sediments, iii) back-barrier lagoonal sediments, iv) a gravel beach deposit representing a sea level stillstand at -5 mamsl, laid down between 7 600 and 5 600 BP, v) another gravel beach deposit representing the well-known Middle Holocene sea level highstand at +2 to +3 mamsl, laid down at ca. 5 000 BP, and which terminated the transgression from the LGM. e) A minor regression to the current sea level, accompanied by progradation of the shoreline to its current position. This progradational marine unit consists almost entirely of sand and grit, reflecting the lack of gravel supply to this part of the coastline in the most recent past. f) Deposition of modern coastal dunes, which cap the pocket beach sequence and are the youngest sediments in the study area. Using trench and hydraulic grab evaluation sample results, in combination with analysis of wave patterns and field observations, the following local controls on the density distribution (ie. concentration) and size distribution of diamonds in the gravel beach deposits (+4, -5 and +2 to +3 mamsl stands) are recognised: a) Gravel beach depositional processes, which are responsible for clast sorting on the beach, have influenced the density and size distribution of diamonds. The infill zone, or beach toe, favours maximum diamond concentration while diamond size decreases from the imbricate zone (intertidal) to the infill zone (subtidal). b) Wave energy is identified as the dominant local control on diamond size distribution, but has also influenced diamond concentration to a limited degree. Larger diamonds are intimately associated with coarser beach gravels, both of which are a reflection of increased wave energy. Higher concentrations of diamonds are sometimes associated with zones of coarser gravel and therefore greater wave energy. c) The time of deposition of the host gravel beach is seen to be the dominant controlling factor with respect to diamond concentration. This is seen as evidence of significant temporal variation in the availability of diamonds in the littoral evironment. A significant reduction (20%) in average diamond size from Site 2 to Site 3, over a distance of only 6 km, is evident. The following were identified as reasons for this reduction in diamond size : a) Longshore sorting processes, of which the long-lived northerly littoral drift is a key part, are known to have played a role in the diminution of diamond size northwards from the Orange River mouth point source. However, it is believed that this can only partly account for the observed 20% reduction in diamond size. b) Input of sediment and smaller diamonds at Site 3, reworked out of an older, Eocene-aged marine succession in the hinterland, is recognised as a possible additional reason for the large reduction in diamond size from Site 2 to Site 3. It is also speculated that the large size of the pocket beach at Site 3, relative to Site 2, may have resulted in lower average wave energy at Site 3, with consequent reduced average diamond size. Diamond size in the beach gravels of Site 3, as well as in beach gravels elsewhere in the Sperrgebiet, is seen to be lognormally-distributed within geologically homogeneous zones. In theory, lognormal mean estimators represent the best method of estimating average diamond size in such cases, whereas the arithmetic mean estimator has the tendency to overestimate when large outlier values occur. Lognormal mean estimators have the added benefit of providing for the calculation of confidence limits, which are becoming increasingly more important as financial lending institutions insist on better quantification of the risk involved in resource estimates. Sample campaign simulations demonstrate, for the kinds of diamond size-frequency distributions typical of beach gravel deposits at Site 3, that there is no significant improvement in the accuracy of average diamond size estimates when lognormal mean estimators are used instead of the arithmetic mean estimator. This is because the variance (a ) of the diamond populations is low, and large outlier values are extremely unlikely to occur. However, simulation of a diamond population with high variance, drawn from a sample of beach gravels near the Orange River mouth, shows that lognormal estimators produce significantly more accurate results when a is large. Since individual diamond weights were not recorded during evaluation sampling of Site 3, numerical solution of lognormal estimators is not possible, and these would need to be solved using a less accurate graphical method. It is therefore recommended that individual diamond weights are recorded in future sampling campaigns, allowing for the use of lognormal mean estimators, and the calculation of confidence limits for average diamond size estimates. , Thesis (MSc) -- Science, Geology, 2004
- Full Text:
- Date Issued: 2004-03
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