Addressing flux suppression, radio frequency interference, and selection of optimal solution intervals during radio interferometric calibration
- Authors: Sob, Ulrich Armel Mbou
- Date: 2020
- Subjects: CubiCal (Software) , Radio -- Interference , Imaging systems in astronomy , Algorithms , Astronomical instruments -- Calibration , Astronomy -- Data processing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/147714 , vital:38663
- Description: The forthcoming Square Kilometre Array is expected to provide answers to some of the most intriguing questions about our Universe. However, as it is already noticeable from MeerKAT and other precursors, the amounts of data produced by these new instruments are significantly challenging to calibrate and image. Calibration of radio interferometric data is usually biased by incomplete sky models and radio frequency interference (RFI) resulting in calibration artefacts that limit the dynamic range and image fidelity of the resulting images. One of the most noticeable of these artefacts is the formation of spurious sources which causes suppression of real emissions. Fortunately, it has been shown that calibration algorithms employing heavy-tailed likelihood functions are less susceptible to this due to their robustness against outliers. Leveraging on recent developments in the field of complex optimisation, we implement a robust calibration algorithm using a Student’s t likelihood function and Wirtinger derivatives. The new algorithm, dubbed the robust solver, is incorporated as a subroutine into the newly released calibration software package CubiCal. We perform statistical analysis on the distribution of visibilities and provide an insight into the functioning of the robust solver and describe different scenarios where it will improve calibration. We use simulations to show that the robust solver effectively reduces the amount of flux suppressed from unmodelled sources both in direction independent and direction dependent calibration. Furthermore, the robust solver is shown to successfully mitigate the effects of low-level RFI when applied to a simulated and a real VLA dataset. Finally, we demonstrate that there are close links between the amount of flux suppressed from sources, the effects of the RFI and the employed solution interval during radio interferometric calibration. Hence, we investigate the effects of solution intervals and the different factors to consider in order to select adequate solution intervals. Furthermore, we propose a practical brute force method for selecting optimal solution intervals. The proposed method is successfully applied to a VLA dataset.
- Full Text:
- Authors: Sob, Ulrich Armel Mbou
- Date: 2020
- Subjects: CubiCal (Software) , Radio -- Interference , Imaging systems in astronomy , Algorithms , Astronomical instruments -- Calibration , Astronomy -- Data processing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/147714 , vital:38663
- Description: The forthcoming Square Kilometre Array is expected to provide answers to some of the most intriguing questions about our Universe. However, as it is already noticeable from MeerKAT and other precursors, the amounts of data produced by these new instruments are significantly challenging to calibrate and image. Calibration of radio interferometric data is usually biased by incomplete sky models and radio frequency interference (RFI) resulting in calibration artefacts that limit the dynamic range and image fidelity of the resulting images. One of the most noticeable of these artefacts is the formation of spurious sources which causes suppression of real emissions. Fortunately, it has been shown that calibration algorithms employing heavy-tailed likelihood functions are less susceptible to this due to their robustness against outliers. Leveraging on recent developments in the field of complex optimisation, we implement a robust calibration algorithm using a Student’s t likelihood function and Wirtinger derivatives. The new algorithm, dubbed the robust solver, is incorporated as a subroutine into the newly released calibration software package CubiCal. We perform statistical analysis on the distribution of visibilities and provide an insight into the functioning of the robust solver and describe different scenarios where it will improve calibration. We use simulations to show that the robust solver effectively reduces the amount of flux suppressed from unmodelled sources both in direction independent and direction dependent calibration. Furthermore, the robust solver is shown to successfully mitigate the effects of low-level RFI when applied to a simulated and a real VLA dataset. Finally, we demonstrate that there are close links between the amount of flux suppressed from sources, the effects of the RFI and the employed solution interval during radio interferometric calibration. Hence, we investigate the effects of solution intervals and the different factors to consider in order to select adequate solution intervals. Furthermore, we propose a practical brute force method for selecting optimal solution intervals. The proposed method is successfully applied to a VLA dataset.
- Full Text:
Developing voice and leadership amongst a group of class captains
- Nehunga, Jacobina Taukondjele
- Authors: Nehunga, Jacobina Taukondjele
- Date: 2020
- Subjects: Educational leadership -- Namibia , Transformational leadership -- Namibia , Leadership in adolescents -- Namibia , Rural schools -- Namibia , School children – Namibia -- Attitudes , School management and organization – Namibia , Cultural Historical Activity Theory
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/145034 , vital:38402
- Description: The notion that leadership can be reduced to that of a formal position such as principalship has become problematic in school leadership research and practice, globally and also in Namibia. It appears that when leadership is concentrated only at the level of a principal within schools, teachers and learners within the same school experience a lack of opportunities to contribute to leadership practices, thus losing a sense of ownership. Supporting a distributed leadership perspective and embracing transformative leadership, this study investigated how learner voice and learner leadership (see for example Mitra and Gross, 2009) can be developed within a group of class captains in a combined school in rural Namibia. Cultural Historical Activity Theory (CHAT) underpinned the study which is located within a critical paradigm. Findings of the study were captured into two phases whereby phase one generated contextual profiling findings through the adoption of qualitative methods such as questionnaires, interviews, document analysis and two other participatory methods of mapping and transect walks. Phase two findings were captured through expansive learning actions in Change Laboratory Workshops. Observation notes, video recording and photographs and informal discussions were used as data sources during this phase. Both inductive and abductive analysis were employed. The findings revealed that a few enabling conditions to class captainship practice existed, but generally there was limited participation of class captains in school leadership. Class captains were seen as merely class representatives and their leadership was confined to a classroom level in the school. They performed more managerial tasks than leadership. It was also revealed that class captainship is not a documented practice in Namibia and it lacks support. Against this backdrop, during phase two of the study, seven contradictions were identified and two contradictions were prioritised for resolution during the Change Laboratory Workshops. Some of the resolutions included the development of a school based guiding document for class captains; an establishment of a class captainship club; and the promotion of a yearly election campaign of class captains. The study recommends more interventionist studies to be conducted on class captainship in order to see the practice documented in terms of policy in Namibia, perhaps in the near future.
- Full Text:
- Authors: Nehunga, Jacobina Taukondjele
- Date: 2020
- Subjects: Educational leadership -- Namibia , Transformational leadership -- Namibia , Leadership in adolescents -- Namibia , Rural schools -- Namibia , School children – Namibia -- Attitudes , School management and organization – Namibia , Cultural Historical Activity Theory
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/145034 , vital:38402
- Description: The notion that leadership can be reduced to that of a formal position such as principalship has become problematic in school leadership research and practice, globally and also in Namibia. It appears that when leadership is concentrated only at the level of a principal within schools, teachers and learners within the same school experience a lack of opportunities to contribute to leadership practices, thus losing a sense of ownership. Supporting a distributed leadership perspective and embracing transformative leadership, this study investigated how learner voice and learner leadership (see for example Mitra and Gross, 2009) can be developed within a group of class captains in a combined school in rural Namibia. Cultural Historical Activity Theory (CHAT) underpinned the study which is located within a critical paradigm. Findings of the study were captured into two phases whereby phase one generated contextual profiling findings through the adoption of qualitative methods such as questionnaires, interviews, document analysis and two other participatory methods of mapping and transect walks. Phase two findings were captured through expansive learning actions in Change Laboratory Workshops. Observation notes, video recording and photographs and informal discussions were used as data sources during this phase. Both inductive and abductive analysis were employed. The findings revealed that a few enabling conditions to class captainship practice existed, but generally there was limited participation of class captains in school leadership. Class captains were seen as merely class representatives and their leadership was confined to a classroom level in the school. They performed more managerial tasks than leadership. It was also revealed that class captainship is not a documented practice in Namibia and it lacks support. Against this backdrop, during phase two of the study, seven contradictions were identified and two contradictions were prioritised for resolution during the Change Laboratory Workshops. Some of the resolutions included the development of a school based guiding document for class captains; an establishment of a class captainship club; and the promotion of a yearly election campaign of class captains. The study recommends more interventionist studies to be conducted on class captainship in order to see the practice documented in terms of policy in Namibia, perhaps in the near future.
- Full Text:
Mineralogy, geochemistry and origin of the Neoproterozoic Xaudum iron-formation in Botswana
- Authors: Ntantiso, Mawande
- Date: 2020
- Subjects: Xaudum iron-formation , Iron ores -- Botswana , Formations (Geology) -- Botswana , Mineralogy -- Botswana , Paleoclimatology -- Proterozoic
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167211 , vital:41447
- Description: Banded iron-formations (BIF) formed in three different geological periods in the Earth’s history, namely the Archean, Paleoproterozoic and Neoproterozoic. Each of these periods has a corresponding index BIF type attributed to them. The oldest is the Archean Algoma-type BIF which is typically dominated by smaller-volume BIF deposits associated with volcanic rocks and greenstone belts. The next is the volumetrically far more abundant Superior-type BIF of the Paleoproterozoic lacking any obvious volcanic relation. The youngest BIFs were deposited after a hiatus of a billion years in the Neoproterozoic and are believed to be genetically linked to Marinoan ice-age. The global re-introduction and distribution of BIF in the Neoproterozoic highlights a shift in the Earth’s tectonics, climate, biosphere and ocean chemistry from the older Archean and Paleoproterozoic counterparts. Various models have been postulated by researchers in attempts to explain how Neoproterozoic iron-formations formed. In all the available models, the Snowball Earth Hypothesis initially proposed by Kirshvink (1992) is an overarching concept. In this study, four cores from the Neoproterozoic Xaudum iron-formation (XIF) in Ngamiland, northwest of Botswana, were sampled and analysed following a partnership between Postgraduate Research in Iron and Manganese Ore Resources (PRIMOR) and Tsodilo Resources Ltd. The study sets out to explore the mineralogy and chemistry of XIF in order to determine its origin, constrain the redox conditions in the paleo-basin, assess it in the context of other Neoproterozoic iron-formations and older Archean and Paleoproterozoic iron-formations, and inform metallurgical processing. The mineralogy of XIF consists of magnetite, quartz, amphibole, garnet, biotite and chlorite in decreasing abundance. This mineral assemblage is characteristic of medium grade metamorphosed iron-formations. Algoma and Superior-type BIFs which experienced late-diagenetic and very low-grade metamorphism have a complex mineral assemblage consisting of hematite, magnetite, quartz, and several carbonate (dolomite-ankerite series and siderite) and silicate phases (greenalite, riebeckite and stilpnomelane). The geochemical results show that XIF has higher Mn3O4 and Al2O3 average contents when compared to Algoma and Superior type BIF. The detrital components in XIF correlate with High Field Strength Elements (HFSE) suggesting increased delivery of siliciclastic material during deposition. This trend is comparable to other NIF deposits suggesting a global high input of siliciclastic material into Neoproterozoic paleodepositional environments. This trend is different from Archean and Paleoproterozoic BIF deposits which are close to pure chemical sediments lacking measurable detrital contributions. In the XIF, bulk-rock Mn3O4 and Al2O3 in drillcore SW have higher averages of 2.4 and 2.6 wt. % respectively, compared to the other three cores. The Mn3O4 shows a positive statistical relationship with Co, suggesting that Neoproterozoic oceans and atmosphere were possibly more oxic than in the Archean and Paleoproterozoic. The Mn3O4 shows an antithetic relationship with Fe2O3 suggesting that the paleobasin was chemically heterogeneous in terms of redox conditions, with Fe2O3 depositing presumably in deeper parts removed from a detrital source, and Mn3O4 depositing possibly more proximal to a paleo-shoreline in a shallower setting where there was higher delivery of siliciclastic material from the continent due to correspondingly higher Al2O3 and TiO2 contents. The REE patterns of XIF show positive-sloping trends of depletion in LREE and enrichment in HREE which resemble those of seawater. However, the REE slope becomes a lot flatter and resembles closer the signature of PAAS and adjacent diamictite facies, which agrees with the idea of high siliciclastic input in the paleobasin comparable to other NIF. XIF also appears to lack clear Ce or Eu anomalies. The lack of the former points to the oceans possibly not being oxic enough to drive the fractionation of Ce into Mn oxides like in the modern oceans, or that the Ce behaviour is obscured by the high siliciclastic input in XIF. Similarly, the lack of positive Eu anomaly shows a weak to absent hydrothermal signal into to modern shallow seawater where Fe and Si were sourced, or detritally derived REE contamination. Extensive weathering under hot and humid climate during glacial retreat is shown by the low K2O/Al2O3 ratios and high CIA values ranging from 80-99. Re-glaciation signifies the return of cold and arid and it is represented by high K2O/Al2O3 ratios and low CIA values ranging from 64-78. The previous genetic models of NIF by Klein (1993), Baldwin et al. (2012) and Lechte and Wallace (2015) provide an essential foundation for the development of a XIF genetic model. The genetic model of XIF proposes deposition on an open continental shelf characterized by a steady influx of detrital material. The seawater has been anoxic since the Paleoproterozoic and further induced by basin stagnation due to the ice covering the basin. Two overlapping oxidative stages are assumed for the precipitation of Fe and Mn across lateral redox gradients in the paleobasin. The exact oxidative pathways and mechanisms for the above processes remains unconstrained.
- Full Text:
- Authors: Ntantiso, Mawande
- Date: 2020
- Subjects: Xaudum iron-formation , Iron ores -- Botswana , Formations (Geology) -- Botswana , Mineralogy -- Botswana , Paleoclimatology -- Proterozoic
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167211 , vital:41447
- Description: Banded iron-formations (BIF) formed in three different geological periods in the Earth’s history, namely the Archean, Paleoproterozoic and Neoproterozoic. Each of these periods has a corresponding index BIF type attributed to them. The oldest is the Archean Algoma-type BIF which is typically dominated by smaller-volume BIF deposits associated with volcanic rocks and greenstone belts. The next is the volumetrically far more abundant Superior-type BIF of the Paleoproterozoic lacking any obvious volcanic relation. The youngest BIFs were deposited after a hiatus of a billion years in the Neoproterozoic and are believed to be genetically linked to Marinoan ice-age. The global re-introduction and distribution of BIF in the Neoproterozoic highlights a shift in the Earth’s tectonics, climate, biosphere and ocean chemistry from the older Archean and Paleoproterozoic counterparts. Various models have been postulated by researchers in attempts to explain how Neoproterozoic iron-formations formed. In all the available models, the Snowball Earth Hypothesis initially proposed by Kirshvink (1992) is an overarching concept. In this study, four cores from the Neoproterozoic Xaudum iron-formation (XIF) in Ngamiland, northwest of Botswana, were sampled and analysed following a partnership between Postgraduate Research in Iron and Manganese Ore Resources (PRIMOR) and Tsodilo Resources Ltd. The study sets out to explore the mineralogy and chemistry of XIF in order to determine its origin, constrain the redox conditions in the paleo-basin, assess it in the context of other Neoproterozoic iron-formations and older Archean and Paleoproterozoic iron-formations, and inform metallurgical processing. The mineralogy of XIF consists of magnetite, quartz, amphibole, garnet, biotite and chlorite in decreasing abundance. This mineral assemblage is characteristic of medium grade metamorphosed iron-formations. Algoma and Superior-type BIFs which experienced late-diagenetic and very low-grade metamorphism have a complex mineral assemblage consisting of hematite, magnetite, quartz, and several carbonate (dolomite-ankerite series and siderite) and silicate phases (greenalite, riebeckite and stilpnomelane). The geochemical results show that XIF has higher Mn3O4 and Al2O3 average contents when compared to Algoma and Superior type BIF. The detrital components in XIF correlate with High Field Strength Elements (HFSE) suggesting increased delivery of siliciclastic material during deposition. This trend is comparable to other NIF deposits suggesting a global high input of siliciclastic material into Neoproterozoic paleodepositional environments. This trend is different from Archean and Paleoproterozoic BIF deposits which are close to pure chemical sediments lacking measurable detrital contributions. In the XIF, bulk-rock Mn3O4 and Al2O3 in drillcore SW have higher averages of 2.4 and 2.6 wt. % respectively, compared to the other three cores. The Mn3O4 shows a positive statistical relationship with Co, suggesting that Neoproterozoic oceans and atmosphere were possibly more oxic than in the Archean and Paleoproterozoic. The Mn3O4 shows an antithetic relationship with Fe2O3 suggesting that the paleobasin was chemically heterogeneous in terms of redox conditions, with Fe2O3 depositing presumably in deeper parts removed from a detrital source, and Mn3O4 depositing possibly more proximal to a paleo-shoreline in a shallower setting where there was higher delivery of siliciclastic material from the continent due to correspondingly higher Al2O3 and TiO2 contents. The REE patterns of XIF show positive-sloping trends of depletion in LREE and enrichment in HREE which resemble those of seawater. However, the REE slope becomes a lot flatter and resembles closer the signature of PAAS and adjacent diamictite facies, which agrees with the idea of high siliciclastic input in the paleobasin comparable to other NIF. XIF also appears to lack clear Ce or Eu anomalies. The lack of the former points to the oceans possibly not being oxic enough to drive the fractionation of Ce into Mn oxides like in the modern oceans, or that the Ce behaviour is obscured by the high siliciclastic input in XIF. Similarly, the lack of positive Eu anomaly shows a weak to absent hydrothermal signal into to modern shallow seawater where Fe and Si were sourced, or detritally derived REE contamination. Extensive weathering under hot and humid climate during glacial retreat is shown by the low K2O/Al2O3 ratios and high CIA values ranging from 80-99. Re-glaciation signifies the return of cold and arid and it is represented by high K2O/Al2O3 ratios and low CIA values ranging from 64-78. The previous genetic models of NIF by Klein (1993), Baldwin et al. (2012) and Lechte and Wallace (2015) provide an essential foundation for the development of a XIF genetic model. The genetic model of XIF proposes deposition on an open continental shelf characterized by a steady influx of detrital material. The seawater has been anoxic since the Paleoproterozoic and further induced by basin stagnation due to the ice covering the basin. Two overlapping oxidative stages are assumed for the precipitation of Fe and Mn across lateral redox gradients in the paleobasin. The exact oxidative pathways and mechanisms for the above processes remains unconstrained.
- Full Text:
A reconciliation study of different resource estimation methods and drill hole spacing as applied to the Langer Heinrich calcrete-hosted uranium deposit, Namibia
- Authors: Baufeldt, Sven
- Date: 2018
- Subjects: Uranium -- Namibia , Calcretes -- Namibia , Carnotite -- Namibia , Uranium mines and mining -- Namibia , Uranium ores -- Geology -- Namibia , Langer-Heinrich Uranium mine
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62527 , vital:28203
- Description: The Langer Heinrich calcrete hosted uranium deposit is situated approximately 90 km to east of the coastal town of Swakopmund in Namibia. It is run by an Australian owned company, Paladin Energy Limited, along with China National Nuclear Corporation (CNNC) who maintain 25% of the shares. Production commenced in 2007 and has been ongoing. Carnotite is the primary and only ore mineral, and the nature of mineralisation within the Langer Heinrich palaeo channel dictates westward-directed continuous open pit mining. Smaller-scale 1micro pits target near-surface, high-grade, lenses toward the east. The high variability in uranium grade over relatively short distances complicates the grade estimation process. This combined with a low uranium price, and a study aimed at optimising of mine production is one of the key drivers for the research presented in this thesis. The efficacy of four resource estimation techniques, commonly used in the mining industry, are investigated by application to variable exploration, infill drilling and grade-control drill pattern spacing. The drill spacing includes regular grids of 50 m x 50 m, 25 m x 25 m and 12,5 m x 12,5 m exploration data. Also included is grade control drill data, drilled on a 4 m x 4 m spacing. The current selective mining unit (SMU) is 4mE x 4mN x 3mRl which is an indication of the minimum dimension whereby the loading equipment can separate ore from waste. The two datasets are processed by four estimation techniques: Inverse Distance Weighting (IDW, squared and cubed), Ordinary Kriging (OK), Multiple Indicator Kriging (MIK) and Conditional Simulation (CS). The two datasets consisted of real-time mining data from pit G1 (micro-pit) in the eastern parts of the mining licence, and pit H1 (continuous larger open pit) in the western area of the palaeo channel. The reconciliation project aims to provide results suitable for devising optimised mining strategies, particularly in future targets where drill spacing can perhaps be improved to provide suitable data with a greater cost saving strategy. Along with the optimal drill spacing or combination thereof, a preferred estimation technique can be suggested and recommended for future operations that involve mining of surficial calcrete-hosted uranium deposits. Results of this study show that 12,5 m x 12,5 m drill spacing provided estimation accuracies similar to that of the narrow 4 m x 4 m grade control spacing (blast hole drilling spacing). The 12,5 m x 12,5m spacing has potential for accurate grade estimations during mining, and could be supplemented by infill downhole radiometric logging on a 4 m x 4 m spacing when 1 Micro pit: Small pits within palaeo channel usually targeted for their near surface high-grade ore necessary. In general, Multiple Indicator Kriging (MIK) provided the most accurate and robust estimations on the wider spaced exploration data and conditional simulation (CS) proved more efficient on the narrow grade control data. These results correspond with current exploration practices for surficial uranium deposits world-wide. Deposit type, therefore complexity and hence SMU sizes play a pivotal role in drill hole planning and estimation accuracies.
- Full Text:
- Authors: Baufeldt, Sven
- Date: 2018
- Subjects: Uranium -- Namibia , Calcretes -- Namibia , Carnotite -- Namibia , Uranium mines and mining -- Namibia , Uranium ores -- Geology -- Namibia , Langer-Heinrich Uranium mine
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62527 , vital:28203
- Description: The Langer Heinrich calcrete hosted uranium deposit is situated approximately 90 km to east of the coastal town of Swakopmund in Namibia. It is run by an Australian owned company, Paladin Energy Limited, along with China National Nuclear Corporation (CNNC) who maintain 25% of the shares. Production commenced in 2007 and has been ongoing. Carnotite is the primary and only ore mineral, and the nature of mineralisation within the Langer Heinrich palaeo channel dictates westward-directed continuous open pit mining. Smaller-scale 1micro pits target near-surface, high-grade, lenses toward the east. The high variability in uranium grade over relatively short distances complicates the grade estimation process. This combined with a low uranium price, and a study aimed at optimising of mine production is one of the key drivers for the research presented in this thesis. The efficacy of four resource estimation techniques, commonly used in the mining industry, are investigated by application to variable exploration, infill drilling and grade-control drill pattern spacing. The drill spacing includes regular grids of 50 m x 50 m, 25 m x 25 m and 12,5 m x 12,5 m exploration data. Also included is grade control drill data, drilled on a 4 m x 4 m spacing. The current selective mining unit (SMU) is 4mE x 4mN x 3mRl which is an indication of the minimum dimension whereby the loading equipment can separate ore from waste. The two datasets are processed by four estimation techniques: Inverse Distance Weighting (IDW, squared and cubed), Ordinary Kriging (OK), Multiple Indicator Kriging (MIK) and Conditional Simulation (CS). The two datasets consisted of real-time mining data from pit G1 (micro-pit) in the eastern parts of the mining licence, and pit H1 (continuous larger open pit) in the western area of the palaeo channel. The reconciliation project aims to provide results suitable for devising optimised mining strategies, particularly in future targets where drill spacing can perhaps be improved to provide suitable data with a greater cost saving strategy. Along with the optimal drill spacing or combination thereof, a preferred estimation technique can be suggested and recommended for future operations that involve mining of surficial calcrete-hosted uranium deposits. Results of this study show that 12,5 m x 12,5 m drill spacing provided estimation accuracies similar to that of the narrow 4 m x 4 m grade control spacing (blast hole drilling spacing). The 12,5 m x 12,5m spacing has potential for accurate grade estimations during mining, and could be supplemented by infill downhole radiometric logging on a 4 m x 4 m spacing when 1 Micro pit: Small pits within palaeo channel usually targeted for their near surface high-grade ore necessary. In general, Multiple Indicator Kriging (MIK) provided the most accurate and robust estimations on the wider spaced exploration data and conditional simulation (CS) proved more efficient on the narrow grade control data. These results correspond with current exploration practices for surficial uranium deposits world-wide. Deposit type, therefore complexity and hence SMU sizes play a pivotal role in drill hole planning and estimation accuracies.
- Full Text:
Women’s perceptions of successful financial retirement planning
- Authors: Durrheim, Meghan
- Date: 2018
- Subjects: Women -- Retirement -- South Africa -- Makhanda , Retirement -- Planning , Retirement income -- Planning , Women -- Finance, Personal , Retired women -- Finance, Personal , Regression analysis
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/60339 , vital:27771
- Description: Financial retirement planning is an important component in ensuring that individuals accumulate sufficient wealth for retirement. Previous research suggests that many individuals are unable to accumulate sufficient wealth for retirement with the problem being particularly acute for women as they tend to spend less time planning financially for retirement when compared to men. Consequently, many women are unable to accumulate sufficient wealth for retirement. Despite the growing need to investigate women’s financial retirement planning, much research tends to focus on financial retirement planning for males. Consequently, there is a growing need to investigate women’s perceptions of successful financial retirement planning, particularly in Grahamstown. After conducting an in-depth literature study and using the study done by Doa (2014), six independent variables were identified: values, time horizon, attitudes, working life-cycle, risk tolerance and financial literacy. These independent variables were identified as factors which could potentially influence women’s perceptions of successful financial retirement planning. A set of hypothesis were formulated to test the relationship between these independent variables and the dependent variable (women’s perceptions of successful financial retirement planning). The study comprised of 101 participants. A principle component analysis was performed to determine the key variables, with the relevant independent factors being renamed: cultural values, personal values, affective attitudes, time horizon knowledge, time horizon consideration, risk tolerance, financial literacy. An ordinal logit regression analysis was then conducted on these renamed variables to determine the influence of these key independent variables on the dependent variable. After controlling for a set of demographic variables the results of the ordinal logit regression analysis revealed that only affective attitudes, time horizon knowledge, and personal values had a significant relationship with women’s perceptions of successful financial retirement planning. Cronbach’s alpha revealed that the measuring instrument of the significant extracted factors was reliable, while Pearson product moment was used to determine correlations between extracted key independent variables and the dependent variable. The investigation into women’s perceptions of successful financial retirement planning enabled insightful information to be gathered which adds to the body of knowledge. In addition, recommendations were formulated in an attempt to assist women when making financial retirement decisions.
- Full Text:
- Authors: Durrheim, Meghan
- Date: 2018
- Subjects: Women -- Retirement -- South Africa -- Makhanda , Retirement -- Planning , Retirement income -- Planning , Women -- Finance, Personal , Retired women -- Finance, Personal , Regression analysis
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/60339 , vital:27771
- Description: Financial retirement planning is an important component in ensuring that individuals accumulate sufficient wealth for retirement. Previous research suggests that many individuals are unable to accumulate sufficient wealth for retirement with the problem being particularly acute for women as they tend to spend less time planning financially for retirement when compared to men. Consequently, many women are unable to accumulate sufficient wealth for retirement. Despite the growing need to investigate women’s financial retirement planning, much research tends to focus on financial retirement planning for males. Consequently, there is a growing need to investigate women’s perceptions of successful financial retirement planning, particularly in Grahamstown. After conducting an in-depth literature study and using the study done by Doa (2014), six independent variables were identified: values, time horizon, attitudes, working life-cycle, risk tolerance and financial literacy. These independent variables were identified as factors which could potentially influence women’s perceptions of successful financial retirement planning. A set of hypothesis were formulated to test the relationship between these independent variables and the dependent variable (women’s perceptions of successful financial retirement planning). The study comprised of 101 participants. A principle component analysis was performed to determine the key variables, with the relevant independent factors being renamed: cultural values, personal values, affective attitudes, time horizon knowledge, time horizon consideration, risk tolerance, financial literacy. An ordinal logit regression analysis was then conducted on these renamed variables to determine the influence of these key independent variables on the dependent variable. After controlling for a set of demographic variables the results of the ordinal logit regression analysis revealed that only affective attitudes, time horizon knowledge, and personal values had a significant relationship with women’s perceptions of successful financial retirement planning. Cronbach’s alpha revealed that the measuring instrument of the significant extracted factors was reliable, while Pearson product moment was used to determine correlations between extracted key independent variables and the dependent variable. The investigation into women’s perceptions of successful financial retirement planning enabled insightful information to be gathered which adds to the body of knowledge. In addition, recommendations were formulated in an attempt to assist women when making financial retirement decisions.
- Full Text:
Diasporic consciousness and Bollywood : South African Indian youth and the meanings they make of Indian film
- Authors: Boshoff, Priscilla A
- Date: 2006
- Subjects: Motion pictures -- India , Youth -- South Africa -- Attitudes , East Indians -- South Africa -- Attitudes , Motion picture industry -- India -- Mumbai
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3503 , http://hdl.handle.net/10962/d1006249 , Motion pictures -- India , Youth -- South Africa -- Attitudes , East Indians -- South Africa -- Attitudes , Motion picture industry -- India -- Mumbai
- Description: A particular youth identity in the South African Indian diaspora is being forged in a nexus o flocal and global forces . The globalisation of Bollywood and its popularity as a global media and the international commodification of the Indian exotic have occurred at the same time as the valorisation of 'difference' in the local political landscape. Indian youth, as young members of the South African Indian diaspora, are inheritors both of a conservative - yet adaptable - home culture and the marginalised identities of apartheid. However, the tensions between their desire to be recognised as both 'modern' South Africans and as ' traditional ' Indians create a space in which they are able to (re)create for themselves an identity that can encompass both their home cultures and the desires of a Westernised modernity through the tropes of Bollywood. Bollywood speaks to its diasporic audiences through representations of an idealised 'traditional yet modern' India. Although India is not a place of return for this young generation, Bollywood representations of successful diasporic Indian culture and participation in the globalised Bollywood industry through concerts and international award ceremonies has provided an opportunity for young Indians in South Africa to re-examine their local Indian identities and feel invited to re-identify with the global diasporas of India.
- Full Text:
- Authors: Boshoff, Priscilla A
- Date: 2006
- Subjects: Motion pictures -- India , Youth -- South Africa -- Attitudes , East Indians -- South Africa -- Attitudes , Motion picture industry -- India -- Mumbai
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3503 , http://hdl.handle.net/10962/d1006249 , Motion pictures -- India , Youth -- South Africa -- Attitudes , East Indians -- South Africa -- Attitudes , Motion picture industry -- India -- Mumbai
- Description: A particular youth identity in the South African Indian diaspora is being forged in a nexus o flocal and global forces . The globalisation of Bollywood and its popularity as a global media and the international commodification of the Indian exotic have occurred at the same time as the valorisation of 'difference' in the local political landscape. Indian youth, as young members of the South African Indian diaspora, are inheritors both of a conservative - yet adaptable - home culture and the marginalised identities of apartheid. However, the tensions between their desire to be recognised as both 'modern' South Africans and as ' traditional ' Indians create a space in which they are able to (re)create for themselves an identity that can encompass both their home cultures and the desires of a Westernised modernity through the tropes of Bollywood. Bollywood speaks to its diasporic audiences through representations of an idealised 'traditional yet modern' India. Although India is not a place of return for this young generation, Bollywood representations of successful diasporic Indian culture and participation in the globalised Bollywood industry through concerts and international award ceremonies has provided an opportunity for young Indians in South Africa to re-examine their local Indian identities and feel invited to re-identify with the global diasporas of India.
- Full Text:
Use of indigenous riverine invertebrates in applied toxicology and water resource-quality management
- Scherman, Patricia A, Palmer, Carolyn G, Muller, Nikite W J
- Authors: Scherman, Patricia A , Palmer, Carolyn G , Muller, Nikite W J
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438061 , vital:73432 , ISBN 1-86845-962-4 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/955-1-03.pdf
- Description: The National Water Policy (DWAF, 1997). and the National Water Act (No 36 of 1998)(NWA) provide the legal and management context for the application of results. The law and the policy are founded on the concepts of equity (fairness of access to water and water services) and sustainability (the opportunity to optimally use water resources now and into the future)(NWA, l (l)(xviii)(b)). The concept of sustainability is based on the understanding that on earth water comes packaged in aquatic ecosystems, and that the product, water, is intimately related to and affected by the structure and functioning of these ecosys-tems.(Aquatic ecosystems include rivers, lakes, wetlands, aquifers and estuaries. Impoundments act as artificial lakes connected to river sys-tems.) A key recognition during the development of the policy and the NWA was that" the environment" does not compete with users for re-sources-the environment (in this case aquatic ecosystems) is the re-source. Therefore a key poiicy of DWAF is that vi resource protection in order to achieve sustainable resource use. Resource protection is achieved through the implementation of resource directed measures (RDM) and source directed controls (SDC).
- Full Text:
Use of indigenous riverine invertebrates in applied toxicology and water resource-quality management
- Authors: Scherman, Patricia A , Palmer, Carolyn G , Muller, Nikite W J
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438061 , vital:73432 , ISBN 1-86845-962-4 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/955-1-03.pdf
- Description: The National Water Policy (DWAF, 1997). and the National Water Act (No 36 of 1998)(NWA) provide the legal and management context for the application of results. The law and the policy are founded on the concepts of equity (fairness of access to water and water services) and sustainability (the opportunity to optimally use water resources now and into the future)(NWA, l (l)(xviii)(b)). The concept of sustainability is based on the understanding that on earth water comes packaged in aquatic ecosystems, and that the product, water, is intimately related to and affected by the structure and functioning of these ecosys-tems.(Aquatic ecosystems include rivers, lakes, wetlands, aquifers and estuaries. Impoundments act as artificial lakes connected to river sys-tems.) A key recognition during the development of the policy and the NWA was that" the environment" does not compete with users for re-sources-the environment (in this case aquatic ecosystems) is the re-source. Therefore a key poiicy of DWAF is that vi resource protection in order to achieve sustainable resource use. Resource protection is achieved through the implementation of resource directed measures (RDM) and source directed controls (SDC).
- Full Text:
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