Power in Africa: a comparison of selected South African and Nigerian dystopian fiction
- Authors: Simelane, Smangaliso
- Date: 2020
- Subjects: Dystopias in literature , Africa -- In literature , South African fiction (English) -- History and criticism , Nigerian fiction (English) -- History and criticism , Beukes, Lauren -- Moxyland , Herne, Lily -- Deadlands , Bandele-Thomas, Biyi, 1967- The Sympathetic Undertaker and Other Dreams , Bandele-Thomas, Biyi, 1967- The Man Who Came in from the Back of Beyond
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/148171 , vital:38716
- Description: Dystopias have frequently been explored in literature to better understand the present and imagine the effects of certain elements of society if taken to a logical extreme. In this way, dystopian fiction can act as both cautionary tales and a form of social commentary. This can be explored within the context of African dystopian fiction where power is a recurring theme, highlighting the anxiety and turbulent history several countries on the continent continue to face. To demonstrate this, I compare selected South African and Nigerian Dystopian texts. With regards to South Africa, I analyse novels by South African science fiction authors Lauren Beukes and Lily Herne, namely Moxyland (2008) and Deadlands (2011) respectively, to investigate how South Africa’s past under Apartheid shapes the segregated societies presented. Nigerian dystopian texts by Biyi Bandele-Thomas, namely The Sympathetic Undertaker And Other Dreams (1993) and The Man Who Came in from the Back of Beyond (1992), are discussed with regards to the way Nigeria’s colonial past and several military juntas have contributed to the kinds of corruption that are depicted. I argue that all four texts warn of the dangers of power, albeit in ways that pertain specifically to their countries of origin. With regards to the South African texts, readers are shown the ways in which those in power can manipulate the desire to survive to keep those they subjugate dependent and, consequently, obedient through what Judith Butler terms ‘passionate attachments’. In the case of the Nigerian dystopias, I argue that Bandele-Thomas’s texts warn of tyranny and effects of the corruption that result from misused power strategies. While the dire settings of dystopian fiction may be grim enough, on their own, to motivate change in the real world, this may not be enough to prevent the texts from becoming pessimistic and fatalistic outlooks. Hence, I seek to understand how the selected novels maintain hope and, consequently, convince readers that the depicted dystopias are ones that can be avoided. Typically, dystopian literature fosters hope by setting the narratives in the future, giving readers hope that they may take steps today to protect their societies from becoming like the damned worlds described by dystopian authors. However, the selected texts are not set in the future. Hence, I explore three literary techniques that might foster hope within the selected African dystopian texts in lieu of temporal distancing. They are, namely: identification with the protagonist, defamiliarization and cognitive estrangement.
- Full Text:
- Date Issued: 2020
- Authors: Simelane, Smangaliso
- Date: 2020
- Subjects: Dystopias in literature , Africa -- In literature , South African fiction (English) -- History and criticism , Nigerian fiction (English) -- History and criticism , Beukes, Lauren -- Moxyland , Herne, Lily -- Deadlands , Bandele-Thomas, Biyi, 1967- The Sympathetic Undertaker and Other Dreams , Bandele-Thomas, Biyi, 1967- The Man Who Came in from the Back of Beyond
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/148171 , vital:38716
- Description: Dystopias have frequently been explored in literature to better understand the present and imagine the effects of certain elements of society if taken to a logical extreme. In this way, dystopian fiction can act as both cautionary tales and a form of social commentary. This can be explored within the context of African dystopian fiction where power is a recurring theme, highlighting the anxiety and turbulent history several countries on the continent continue to face. To demonstrate this, I compare selected South African and Nigerian Dystopian texts. With regards to South Africa, I analyse novels by South African science fiction authors Lauren Beukes and Lily Herne, namely Moxyland (2008) and Deadlands (2011) respectively, to investigate how South Africa’s past under Apartheid shapes the segregated societies presented. Nigerian dystopian texts by Biyi Bandele-Thomas, namely The Sympathetic Undertaker And Other Dreams (1993) and The Man Who Came in from the Back of Beyond (1992), are discussed with regards to the way Nigeria’s colonial past and several military juntas have contributed to the kinds of corruption that are depicted. I argue that all four texts warn of the dangers of power, albeit in ways that pertain specifically to their countries of origin. With regards to the South African texts, readers are shown the ways in which those in power can manipulate the desire to survive to keep those they subjugate dependent and, consequently, obedient through what Judith Butler terms ‘passionate attachments’. In the case of the Nigerian dystopias, I argue that Bandele-Thomas’s texts warn of tyranny and effects of the corruption that result from misused power strategies. While the dire settings of dystopian fiction may be grim enough, on their own, to motivate change in the real world, this may not be enough to prevent the texts from becoming pessimistic and fatalistic outlooks. Hence, I seek to understand how the selected novels maintain hope and, consequently, convince readers that the depicted dystopias are ones that can be avoided. Typically, dystopian literature fosters hope by setting the narratives in the future, giving readers hope that they may take steps today to protect their societies from becoming like the damned worlds described by dystopian authors. However, the selected texts are not set in the future. Hence, I explore three literary techniques that might foster hope within the selected African dystopian texts in lieu of temporal distancing. They are, namely: identification with the protagonist, defamiliarization and cognitive estrangement.
- Full Text:
- Date Issued: 2020
An analysis of the roles and functions of teachers’ gestures as visualisation tools in the teaching of mathematics at the junior primary phase (Grades 0 –3)
- Authors: Namakalu, Dietlinde Nelao
- Date: 2019
- Subjects: Gesture , Gesture in mathematics education , Visual learning , Visualization , Education, Elementary -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/96713 , vital:31311
- Description: There is ample evidence in the literature that gestures are important hand and bodily actions that play vital roles during interactions between learners and teachers in the mathematics classroom. These gestures enable both the teacher and the learner to visualise mathematical concepts and ideas. The aim of this Namibian interpretive case study, located in enactivist theory, was to analyse the types of gestures that three selected teachers at the junior primary phase (Grades 0–3) used in their teaching of mathematics. The study also interrogated the roles that these gestures played in the teaching process of the three teachers. As I intended to analyse the types of gestures the selected teachers used and understand their views and perceptions of the roles and functions their gestures played as visualisation tools in the teaching of mathematics, I observed ten lessons of each teacher and video recorded them. I then interviewed them (one-on-one stimulus-recall interviews) and interpreted the gestures they used and utterances they made about using these gestures. The types of gestures that the participating teachers used are classified according to McNeill‘s (1992) framework, namely pointing (deictic) gestures, iconic (illustrators) gestures, metaphoric gestures, beat (motor) gestures and symbolic (emblems) gestures. The study found that the participating teachers incorporated a variety of gestures into their lessons and used them strategically. According to the teachers, gestures made the lessons interesting and encouraged active participation of the learners in the lessons. The teachers also revealed that gestures assist in explaining mathematical concepts and thus affected the learners‘ understanding positively. This study strongly suggests that the usefulness and efficacy of employing gestures as visualisation tools in mathematics education should be strategically harnessed.
- Full Text:
- Date Issued: 2019
- Authors: Namakalu, Dietlinde Nelao
- Date: 2019
- Subjects: Gesture , Gesture in mathematics education , Visual learning , Visualization , Education, Elementary -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/96713 , vital:31311
- Description: There is ample evidence in the literature that gestures are important hand and bodily actions that play vital roles during interactions between learners and teachers in the mathematics classroom. These gestures enable both the teacher and the learner to visualise mathematical concepts and ideas. The aim of this Namibian interpretive case study, located in enactivist theory, was to analyse the types of gestures that three selected teachers at the junior primary phase (Grades 0–3) used in their teaching of mathematics. The study also interrogated the roles that these gestures played in the teaching process of the three teachers. As I intended to analyse the types of gestures the selected teachers used and understand their views and perceptions of the roles and functions their gestures played as visualisation tools in the teaching of mathematics, I observed ten lessons of each teacher and video recorded them. I then interviewed them (one-on-one stimulus-recall interviews) and interpreted the gestures they used and utterances they made about using these gestures. The types of gestures that the participating teachers used are classified according to McNeill‘s (1992) framework, namely pointing (deictic) gestures, iconic (illustrators) gestures, metaphoric gestures, beat (motor) gestures and symbolic (emblems) gestures. The study found that the participating teachers incorporated a variety of gestures into their lessons and used them strategically. According to the teachers, gestures made the lessons interesting and encouraged active participation of the learners in the lessons. The teachers also revealed that gestures assist in explaining mathematical concepts and thus affected the learners‘ understanding positively. This study strongly suggests that the usefulness and efficacy of employing gestures as visualisation tools in mathematics education should be strategically harnessed.
- Full Text:
- Date Issued: 2019
The English East India Company and the British Crown: c. 1795-1803, the first occupation at the Cape of Good Hope
- Authors: Jordan, Calvin
- Date: 2018
- Subjects: East India Company , East India Company -- Influence , Cape of Good Hope (Colony) , Cape of Good Hope (South Africa) -- History -- 1795-1872 , Cape of Good Hope (South Africa) -- Politics and government -- 1795-1872 , British -- South Africa -- History -- 19th century , Great Britain -- Colonies -- Commerce , Great Britain -- Colonies -- Administration -- History -- 19th century , Merchant marine -- Great Britain -- History
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/63164 , vital:28369
- Description: My thesis aims to investigate the relationship between the English East India Company (EEIC) and the British colonial administration at the Cape of Good Hope during the first British occupation (1795 to 1803). Studies and literature that concern the EEIC have rarely gone beyond the surface, detailing the presence of the EEIC at the Cape, and neglecting the Company’s involvement in the administration thereof. My thesis draws on prior works but attempts to address both temporal and spatial gaps in this literature on the Atlantic and Indian Ocean, and the history of the EEIC. This study takes note of the seaborne related activity around the ports, bays and islands at the Cape – including the regulation of these spaces and issues related to securing British trade and colonial possessions more generally. I question the framing of the Cape primarily as a constituent of a national unit by locating the colony within a broader global and maritime context. A key interest is to determine the degree to which the EEIC influenced and participated in the British governance of the Cape, particularly by exploring the maritime dimensions of the relationship between the EEIC and colonial governance during this particular period. This involves understanding the embeddedness of the Cape in British (Crown and Company) networks and the constitution of a ‘British maritime zone’. This study uses archival sources drawn from the British colonial government records, Company records, and the private diaries and letters of Lady Anne Barnard that relate to the Cape. It is shown that a uniquely configured governance convention was constituted to secure the mutual commercial and imperial interests of both Crown and Company. By keeping the Cape secure, the British sought to keep their greater seaborne Empire secure. This study reveals that the EEIC was significantly involved in and influenced the way the British administration governed the Cape.
- Full Text:
- Date Issued: 2018
- Authors: Jordan, Calvin
- Date: 2018
- Subjects: East India Company , East India Company -- Influence , Cape of Good Hope (Colony) , Cape of Good Hope (South Africa) -- History -- 1795-1872 , Cape of Good Hope (South Africa) -- Politics and government -- 1795-1872 , British -- South Africa -- History -- 19th century , Great Britain -- Colonies -- Commerce , Great Britain -- Colonies -- Administration -- History -- 19th century , Merchant marine -- Great Britain -- History
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/63164 , vital:28369
- Description: My thesis aims to investigate the relationship between the English East India Company (EEIC) and the British colonial administration at the Cape of Good Hope during the first British occupation (1795 to 1803). Studies and literature that concern the EEIC have rarely gone beyond the surface, detailing the presence of the EEIC at the Cape, and neglecting the Company’s involvement in the administration thereof. My thesis draws on prior works but attempts to address both temporal and spatial gaps in this literature on the Atlantic and Indian Ocean, and the history of the EEIC. This study takes note of the seaborne related activity around the ports, bays and islands at the Cape – including the regulation of these spaces and issues related to securing British trade and colonial possessions more generally. I question the framing of the Cape primarily as a constituent of a national unit by locating the colony within a broader global and maritime context. A key interest is to determine the degree to which the EEIC influenced and participated in the British governance of the Cape, particularly by exploring the maritime dimensions of the relationship between the EEIC and colonial governance during this particular period. This involves understanding the embeddedness of the Cape in British (Crown and Company) networks and the constitution of a ‘British maritime zone’. This study uses archival sources drawn from the British colonial government records, Company records, and the private diaries and letters of Lady Anne Barnard that relate to the Cape. It is shown that a uniquely configured governance convention was constituted to secure the mutual commercial and imperial interests of both Crown and Company. By keeping the Cape secure, the British sought to keep their greater seaborne Empire secure. This study reveals that the EEIC was significantly involved in and influenced the way the British administration governed the Cape.
- Full Text:
- Date Issued: 2018
The role of ecological processes in structuring reef fish communities in the Agulhas Ecoregion, South Africa
- Authors: Dyer, Alexander
- Date: 2018
- Subjects: Reef fishes -- South Africa -- Agulhas, Cape (Cape) , Reef fishes -- Ecology -- South Africa -- Agulhas, Cape (Cape) , Marine biodiversity -- South Africa -- Agulhas, Cape (Cape) , Biotic communities -- South Africa -- Agulhas, Cape (Cape) , Sparidae -- South Africa -- Agulhas, Cape (Cape) , Reef fishes -- Size -- South Africa -- Agulhas, Cape (Cape) , Baited remote underwater stereo-video systems (stereo-BRUVs)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63899 , vital:28504
- Description: Local, niche-based processes, which arise from the interplay between biotic interactions and abiotic constraints are considered to be important regulators of community structure. However, it is increasingly recognised that patterns of diversity can also be strongly influenced by dispersal-driven processes. While empirical research on the diversity of coral reef fishes on shallow tropical reefs has contributed greatly to the development of general concepts in ecology, there have been considerably fewer studies on the processes which shape the diversity of fish communities on shallow (10 - 30 m) and deep (30 - 75 m) rocky reefs. Consequently, it is less clear at which spatial scales niche partitioning and dispersal limitation contribute most strongly to the structure of reef-associated fish communities within rocky reef ecosystems. To address this caveat, research was conducted at four rocky reef complexes within the warm-temperate Agulhas Ecoregion, South Africa. The diversity of reef-associated fishes was sampled by baited remote underwater stereo-video systems (stereo-BRUVs) to incorporate the range of heterogeneous reef habitat in Tsitsikamma National Park Marine Protected Area (TNP MPA) and Algoa Bay (AB). To examine how niche-based and dispersal-driven processes influence patterns of diversity among species within the dominant family of resident fishes, the sparids (Sparidae), components of diversity were quantified at several spatial scales. Turnover in the number of species which locally co-occurred was found to be largely driven by the limited dispersal of species over hundreds of kilometres. When relative species abundances were taken into account, sparid communities were characterised by higher than expected rates of compositional turnover among local habitat patches separated by hundreds to thousands of metres of contiguous reef. Patterns of compositional turnover were associated with the spatial aggregation of conspecifics, particularly at scales which facilitate the post-settlement dispersal of fishes. Niche-based segregation of species along the depth gradient was found to be the primary driver of compositional turnover among both protected and exploited communities. However, spatial structuring within reefs, which was independent of variation in the environment, suggests that compositional differences among communities are also influenced by the limited post-settlement dispersal of resident fishes to adjacent areas during their ontogeny. Together, the results suggest that the diversity of reef-associated sparids is likely to depend both on an adequate diversity of suitable reef habitat and a sufficient degree of spatial connectivity to facilitate ontogenetic habitat shifts. Taxon-based descriptors of diversity do not adequately account for ecological difference among conspecifics within size-structured populations. To test whether differences in body size facilitated coexistence among sparid fishes, the number of species which coexisted at the local scale was related to variation in the size structure of communities. In communities which have been historically protected from fishing, local coexistence between a greater number of species was promoted by reduced levels of intraspecific variation in size of fishes. This suggests that, among species with similar trophic requirements, further niche segregation along a prey-size and body-size gradient is likely to mitigate the direct impacts of competition for shared food resources. Among exploited communities, size structure did not influence the number of species which coexisted at the local scale. This finding suggests that fishing-induced mortality of larger-bodied fishes is likely to remove some of the constraints to colonisation which arise from asymmetries in competitive fitness between small and large-bodied fishes. Together, these results highlight the importance of post-settlement processes and population size structure to the maintenance of reef-associated fish diversity within contiguous rocky reef habitats.
- Full Text:
- Date Issued: 2018
- Authors: Dyer, Alexander
- Date: 2018
- Subjects: Reef fishes -- South Africa -- Agulhas, Cape (Cape) , Reef fishes -- Ecology -- South Africa -- Agulhas, Cape (Cape) , Marine biodiversity -- South Africa -- Agulhas, Cape (Cape) , Biotic communities -- South Africa -- Agulhas, Cape (Cape) , Sparidae -- South Africa -- Agulhas, Cape (Cape) , Reef fishes -- Size -- South Africa -- Agulhas, Cape (Cape) , Baited remote underwater stereo-video systems (stereo-BRUVs)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63899 , vital:28504
- Description: Local, niche-based processes, which arise from the interplay between biotic interactions and abiotic constraints are considered to be important regulators of community structure. However, it is increasingly recognised that patterns of diversity can also be strongly influenced by dispersal-driven processes. While empirical research on the diversity of coral reef fishes on shallow tropical reefs has contributed greatly to the development of general concepts in ecology, there have been considerably fewer studies on the processes which shape the diversity of fish communities on shallow (10 - 30 m) and deep (30 - 75 m) rocky reefs. Consequently, it is less clear at which spatial scales niche partitioning and dispersal limitation contribute most strongly to the structure of reef-associated fish communities within rocky reef ecosystems. To address this caveat, research was conducted at four rocky reef complexes within the warm-temperate Agulhas Ecoregion, South Africa. The diversity of reef-associated fishes was sampled by baited remote underwater stereo-video systems (stereo-BRUVs) to incorporate the range of heterogeneous reef habitat in Tsitsikamma National Park Marine Protected Area (TNP MPA) and Algoa Bay (AB). To examine how niche-based and dispersal-driven processes influence patterns of diversity among species within the dominant family of resident fishes, the sparids (Sparidae), components of diversity were quantified at several spatial scales. Turnover in the number of species which locally co-occurred was found to be largely driven by the limited dispersal of species over hundreds of kilometres. When relative species abundances were taken into account, sparid communities were characterised by higher than expected rates of compositional turnover among local habitat patches separated by hundreds to thousands of metres of contiguous reef. Patterns of compositional turnover were associated with the spatial aggregation of conspecifics, particularly at scales which facilitate the post-settlement dispersal of fishes. Niche-based segregation of species along the depth gradient was found to be the primary driver of compositional turnover among both protected and exploited communities. However, spatial structuring within reefs, which was independent of variation in the environment, suggests that compositional differences among communities are also influenced by the limited post-settlement dispersal of resident fishes to adjacent areas during their ontogeny. Together, the results suggest that the diversity of reef-associated sparids is likely to depend both on an adequate diversity of suitable reef habitat and a sufficient degree of spatial connectivity to facilitate ontogenetic habitat shifts. Taxon-based descriptors of diversity do not adequately account for ecological difference among conspecifics within size-structured populations. To test whether differences in body size facilitated coexistence among sparid fishes, the number of species which coexisted at the local scale was related to variation in the size structure of communities. In communities which have been historically protected from fishing, local coexistence between a greater number of species was promoted by reduced levels of intraspecific variation in size of fishes. This suggests that, among species with similar trophic requirements, further niche segregation along a prey-size and body-size gradient is likely to mitigate the direct impacts of competition for shared food resources. Among exploited communities, size structure did not influence the number of species which coexisted at the local scale. This finding suggests that fishing-induced mortality of larger-bodied fishes is likely to remove some of the constraints to colonisation which arise from asymmetries in competitive fitness between small and large-bodied fishes. Together, these results highlight the importance of post-settlement processes and population size structure to the maintenance of reef-associated fish diversity within contiguous rocky reef habitats.
- Full Text:
- Date Issued: 2018
A stratigraphic, petrographic and geochemical study of the gamagara formation at the maremane dome, Northern Cape province, South Africa
- Authors: Cousins, David Patrick
- Date: 2017
- Subjects: Iron ores -- Geology -- South Africa -- Northern Cape , Geology -- South Africa -- Northern Cape , Mineralogy -- South Africa -- Northern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4679 , vital:20711
- Description: Between 80 and 90 percent of the potential iron ore reserves in the Griqualand West basin in the Northern Cape province of South Africa is situated in the Asbesheuwels Iron-formation immediately below an unconformity that separates it from the Gamagara Formation of the Olifantshoek Supergroup. This extensive regional unconformity marks a lengthy period of non-deposition and erosion which preceded the deposition of the Gamagara Formation. Due to the nature of the intimate relationship between the shales and iron ore body, specifically on the Maremane dome, new insights into the Gamagara Formation were required. The thesis provides a renewed stratigraphic, petrographic and geochemical study on the Gamagara Formation and relates it to previous studies done on the lateral correlative Mapedi Formation, some 70 km north of the Maremane dome. The use of 10 newly available drill-cores selected from across the Maremane Dome allows for regional correlations to be made in a study which employs petrographic/mineralogical investigations using transmitted/reflected light microscopy, XRD and EPMA, complimented by traditional whole-rock geochemical analysis of majors, traces, rare earth elements and Nd isotopes. At the base of the Gamagara lie conglomerates representing an alluvial fan deposit, overlying this, shale and quartzite successions represent progradational delta lobes. The deltas are interpreted to be tide- dominated as indicated by a combination of features including: microbial mat growth, intertidal deposition in the delta top, sand bars and flaser laminations in the upward coarsening quartzite units of the delta front. Transgression is indicated by periodic transgressive lag deposits. A variety of sedimentary structures and textural features are described that can be interpreted as the results of microbial mat colonization on the sediment surface. Although in none of the described features can it irrefutably be proven that they are microbial mat deposits, the observed features are consistent with such an interpretation and should be considered indicators of possible microbial mat presence in the Gamagara Formation. Hydrothermal modifications are identified in various units of the Gamagara Formation and seem to occur as separate events. Basal white shales show mobility of Al and slight HFSE enrichments, while overlying red shales record HFSE, K and Fe enrichments. K-metasomatism has been known to occur in the underlying paleoweathering profile of the Transvaal Supergroup (Ongeluk lavas) a unit which is interpreted as the most likely provenance for the mid-to-upper shale lithofacies of the Gamagara Formation. Highly alkaline F-bearing brines had the ability to mobilize titania and fluorapatite, reset Nd isotope systematics and ultimately enriched HFSE concentrations in the red shales of the Gamagara Formation. As the same enrichment is evident in the Mapedi Formation, the event possibly represents unconformity related fluid flow on a regional scale (~140 km). Nd-isotopes record an isotopic disturbance concurrent with the HFSE enrichment and Tdm model ages suggest disruption (and enrichment) occurred between 1.73 and 1.86 Ga. Following this, Fe-addition occurred by epigenetic mechanisms similar to those of MVT-type deposits. Although gaps in the current understanding of the modifications of the Gamagara Formation exist, such events may have far reaching implications for the underlying iron ore bodies and the possibility arises that the genesis and/or epigenetic modification of the ore bodies of the Transvaal Supergroup may be casually linked to the same fluid-migration event/s.
- Full Text:
- Date Issued: 2017
- Authors: Cousins, David Patrick
- Date: 2017
- Subjects: Iron ores -- Geology -- South Africa -- Northern Cape , Geology -- South Africa -- Northern Cape , Mineralogy -- South Africa -- Northern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4679 , vital:20711
- Description: Between 80 and 90 percent of the potential iron ore reserves in the Griqualand West basin in the Northern Cape province of South Africa is situated in the Asbesheuwels Iron-formation immediately below an unconformity that separates it from the Gamagara Formation of the Olifantshoek Supergroup. This extensive regional unconformity marks a lengthy period of non-deposition and erosion which preceded the deposition of the Gamagara Formation. Due to the nature of the intimate relationship between the shales and iron ore body, specifically on the Maremane dome, new insights into the Gamagara Formation were required. The thesis provides a renewed stratigraphic, petrographic and geochemical study on the Gamagara Formation and relates it to previous studies done on the lateral correlative Mapedi Formation, some 70 km north of the Maremane dome. The use of 10 newly available drill-cores selected from across the Maremane Dome allows for regional correlations to be made in a study which employs petrographic/mineralogical investigations using transmitted/reflected light microscopy, XRD and EPMA, complimented by traditional whole-rock geochemical analysis of majors, traces, rare earth elements and Nd isotopes. At the base of the Gamagara lie conglomerates representing an alluvial fan deposit, overlying this, shale and quartzite successions represent progradational delta lobes. The deltas are interpreted to be tide- dominated as indicated by a combination of features including: microbial mat growth, intertidal deposition in the delta top, sand bars and flaser laminations in the upward coarsening quartzite units of the delta front. Transgression is indicated by periodic transgressive lag deposits. A variety of sedimentary structures and textural features are described that can be interpreted as the results of microbial mat colonization on the sediment surface. Although in none of the described features can it irrefutably be proven that they are microbial mat deposits, the observed features are consistent with such an interpretation and should be considered indicators of possible microbial mat presence in the Gamagara Formation. Hydrothermal modifications are identified in various units of the Gamagara Formation and seem to occur as separate events. Basal white shales show mobility of Al and slight HFSE enrichments, while overlying red shales record HFSE, K and Fe enrichments. K-metasomatism has been known to occur in the underlying paleoweathering profile of the Transvaal Supergroup (Ongeluk lavas) a unit which is interpreted as the most likely provenance for the mid-to-upper shale lithofacies of the Gamagara Formation. Highly alkaline F-bearing brines had the ability to mobilize titania and fluorapatite, reset Nd isotope systematics and ultimately enriched HFSE concentrations in the red shales of the Gamagara Formation. As the same enrichment is evident in the Mapedi Formation, the event possibly represents unconformity related fluid flow on a regional scale (~140 km). Nd-isotopes record an isotopic disturbance concurrent with the HFSE enrichment and Tdm model ages suggest disruption (and enrichment) occurred between 1.73 and 1.86 Ga. Following this, Fe-addition occurred by epigenetic mechanisms similar to those of MVT-type deposits. Although gaps in the current understanding of the modifications of the Gamagara Formation exist, such events may have far reaching implications for the underlying iron ore bodies and the possibility arises that the genesis and/or epigenetic modification of the ore bodies of the Transvaal Supergroup may be casually linked to the same fluid-migration event/s.
- Full Text:
- Date Issued: 2017
Data compression, field of interest shaping and fast algorithms for direction-dependent deconvolution in radio interferometry
- Authors: Atemkeng, Marcellin T
- Date: 2017
- Subjects: Radio astronomy , Solar radio emission , Radio interferometers , Signal processing -- Digital techniques , Algorithms , Data compression (Computer science)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/6324 , vital:21089
- Description: In radio interferometry, observed visibilities are intrinsically sampled at some interval in time and frequency. Modern interferometers are capable of producing data at very high time and frequency resolution; practical limits on storage and computation costs require that some form of data compression be imposed. The traditional form of compression is simple averaging of the visibilities over coarser time and frequency bins. This has an undesired side effect: the resulting averaged visibilities “decorrelate”, and do so differently depending on the baseline length and averaging interval. This translates into a non-trivial signature in the image domain known as “smearing”, which manifests itself as an attenuation in amplitude towards off-centre sources. With the increasing fields of view and/or longer baselines employed in modern and future instruments, the trade-off between data rate and smearing becomes increasingly unfavourable. Averaging also results in baseline length and a position-dependent point spread function (PSF). In this work, we investigate alternative approaches to low-loss data compression. We show that averaging of the visibility data can be understood as a form of convolution by a boxcar-like window function, and that by employing alternative baseline-dependent window functions a more optimal interferometer smearing response may be induced. Specifically, we can improve amplitude response over a chosen field of interest and attenuate sources outside the field of interest. The main cost of this technique is a reduction in nominal sensitivity; we investigate the smearing vs. sensitivity trade-off and show that in certain regimes a favourable compromise can be achieved. We show the application of this technique to simulated data from the Jansky Very Large Array and the European Very Long Baseline Interferometry Network. Furthermore, we show that the position-dependent PSF shape induced by averaging can be approximated using linear algebraic properties to effectively reduce the computational complexity for evaluating the PSF at each sky position. We conclude by implementing a position-dependent PSF deconvolution in an imaging and deconvolution framework. Using the Low-Frequency Array radio interferometer, we show that deconvolution with position-dependent PSFs results in higher image fidelity compared to a simple CLEAN algorithm and its derivatives.
- Full Text:
- Date Issued: 2017
- Authors: Atemkeng, Marcellin T
- Date: 2017
- Subjects: Radio astronomy , Solar radio emission , Radio interferometers , Signal processing -- Digital techniques , Algorithms , Data compression (Computer science)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/6324 , vital:21089
- Description: In radio interferometry, observed visibilities are intrinsically sampled at some interval in time and frequency. Modern interferometers are capable of producing data at very high time and frequency resolution; practical limits on storage and computation costs require that some form of data compression be imposed. The traditional form of compression is simple averaging of the visibilities over coarser time and frequency bins. This has an undesired side effect: the resulting averaged visibilities “decorrelate”, and do so differently depending on the baseline length and averaging interval. This translates into a non-trivial signature in the image domain known as “smearing”, which manifests itself as an attenuation in amplitude towards off-centre sources. With the increasing fields of view and/or longer baselines employed in modern and future instruments, the trade-off between data rate and smearing becomes increasingly unfavourable. Averaging also results in baseline length and a position-dependent point spread function (PSF). In this work, we investigate alternative approaches to low-loss data compression. We show that averaging of the visibility data can be understood as a form of convolution by a boxcar-like window function, and that by employing alternative baseline-dependent window functions a more optimal interferometer smearing response may be induced. Specifically, we can improve amplitude response over a chosen field of interest and attenuate sources outside the field of interest. The main cost of this technique is a reduction in nominal sensitivity; we investigate the smearing vs. sensitivity trade-off and show that in certain regimes a favourable compromise can be achieved. We show the application of this technique to simulated data from the Jansky Very Large Array and the European Very Long Baseline Interferometry Network. Furthermore, we show that the position-dependent PSF shape induced by averaging can be approximated using linear algebraic properties to effectively reduce the computational complexity for evaluating the PSF at each sky position. We conclude by implementing a position-dependent PSF deconvolution in an imaging and deconvolution framework. Using the Low-Frequency Array radio interferometer, we show that deconvolution with position-dependent PSFs results in higher image fidelity compared to a simple CLEAN algorithm and its derivatives.
- Full Text:
- Date Issued: 2017
The identification of key vulnerability components within Solomon Islands coastal communities
- Authors: Malherbe, Willem Stefanus
- Date: 2017
- Subjects: Solomon Islands -- Environmental conditions , Coastal ecology -- Solomon Islands , Island ecology -- Solomon Islands , Climatic changes -- Solomon Islands , Sociology, Urban -- Solomon Islands , Sociology, Rural -- Solomon Islands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:21184 , http://hdl.handle.net/10962/6827
- Description: The impacts of climate change are disproportionally felt across the planet, with small island developing states some of the countries most at risk. Furthermore, climate change may compound existing problems such as over harvested resources, leading to knock-on effects on national economies. Both direct and indirect stressors may impact communities differently based on their level of exposure to stressors, their intrinsic sensitivity to these stressors, and their ability to adapt to stressors. This study aims to answer the primary research question: Why are some communities more vulnerable than others? A vulnerability assessment is used to identify both vulnerable and non-vulnerable attributes of Solomon Islands’ communities. Surveys comprised a comprehensive questionnaire to draw inference on each vulnerability category; sensitivity, exposure and adaptive capacity, along with their various components and subcomponents. An analysis of household and community livelihood strategies was conducted to compliment vulnerability scores and provide a deeper understanding of livelihood practises. As is expected of small island states, exposure presents the biggest threat to coastal communities. Within this category, environmental changes and personal exposure from shoreline erosion and safety at sea provide evidence of high vulnerability. Within the sensitivity category, the cultural importance of fishing, as well as attachment to place and fishing, renders communities more vulnerable. Simultaneously, local ecological knowledge and economic dependence on resources other than fishing proved to be resilient attributes by decreasing vulnerability. Low vulnerability scores for the adaptive capacity category were achieved by communities where physical capital, such as community infrastructure, was evident. A lack of both institutional support and bridging of social capital were attributes which contributed to community vulnerability. This study has identified key attributes that have both positive and negative effects on the vulnerability of Solomon Islands communities. Having done this, I have also attempted to determine the drivers that render some attributes more vulnerable than others. It is acknowledged that the drivers of all key attributes of vulnerability is required to determine areas where adaptation plans will be most effective. Importantly, drivers of high vulnerability should not be considered as the primary focus of adaptation planning, but also the drivers of low vulnerability, such as community cohesion, which provide resilience within communities.
- Full Text:
- Date Issued: 2017
- Authors: Malherbe, Willem Stefanus
- Date: 2017
- Subjects: Solomon Islands -- Environmental conditions , Coastal ecology -- Solomon Islands , Island ecology -- Solomon Islands , Climatic changes -- Solomon Islands , Sociology, Urban -- Solomon Islands , Sociology, Rural -- Solomon Islands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:21184 , http://hdl.handle.net/10962/6827
- Description: The impacts of climate change are disproportionally felt across the planet, with small island developing states some of the countries most at risk. Furthermore, climate change may compound existing problems such as over harvested resources, leading to knock-on effects on national economies. Both direct and indirect stressors may impact communities differently based on their level of exposure to stressors, their intrinsic sensitivity to these stressors, and their ability to adapt to stressors. This study aims to answer the primary research question: Why are some communities more vulnerable than others? A vulnerability assessment is used to identify both vulnerable and non-vulnerable attributes of Solomon Islands’ communities. Surveys comprised a comprehensive questionnaire to draw inference on each vulnerability category; sensitivity, exposure and adaptive capacity, along with their various components and subcomponents. An analysis of household and community livelihood strategies was conducted to compliment vulnerability scores and provide a deeper understanding of livelihood practises. As is expected of small island states, exposure presents the biggest threat to coastal communities. Within this category, environmental changes and personal exposure from shoreline erosion and safety at sea provide evidence of high vulnerability. Within the sensitivity category, the cultural importance of fishing, as well as attachment to place and fishing, renders communities more vulnerable. Simultaneously, local ecological knowledge and economic dependence on resources other than fishing proved to be resilient attributes by decreasing vulnerability. Low vulnerability scores for the adaptive capacity category were achieved by communities where physical capital, such as community infrastructure, was evident. A lack of both institutional support and bridging of social capital were attributes which contributed to community vulnerability. This study has identified key attributes that have both positive and negative effects on the vulnerability of Solomon Islands communities. Having done this, I have also attempted to determine the drivers that render some attributes more vulnerable than others. It is acknowledged that the drivers of all key attributes of vulnerability is required to determine areas where adaptation plans will be most effective. Importantly, drivers of high vulnerability should not be considered as the primary focus of adaptation planning, but also the drivers of low vulnerability, such as community cohesion, which provide resilience within communities.
- Full Text:
- Date Issued: 2017
An analysis of challenges facing decentralisation of sector education and training authorities in the province of the Eastern Cape
- Authors: Gazi, Luvo Ndileka
- Date: 2010
- Subjects: Schools -- Decentralization -- South Africa -- Eastern Cape , School management and organization -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: vital:8193 , http://hdl.handle.net/10948/1346 , Schools -- Decentralization -- South Africa -- Eastern Cape , School management and organization -- South Africa -- Eastern Cape
- Description: It is largely believed that decentralisation promotes efficiency in organisations. This paper analyses the challenges facing decentralisation of Sector Education and Training Authorities (SETAs) in the Province of the Eastern Cape. It is demonstrated that the form of decentralisation followed by SETAs in the Province of the Eastern Cape, where constant referral of matters to head offices for decisions and instruction before any action is taken, by them is the biggest challenge. Yet these important institutions are mandated by government to equip South Africans with skills to enable them to succeed in the global market and to offer opportunities to individuals and communities for self advancement and to play a productive role in society are frustrated by unnecessary interference from SETA national offices on their affairs at the provincial government level, which constrains effective decentralisation. However, the objectives of the study are to: - Analyse the challenges of decentralisation by SETAs in the Province of the Eastern Cape; - Provide an overview of the impact of SETA provincial offices on requisite skills in the province; - Investigate the advantages and disadvantages of decentralising SETAs in the provinces. These objectives have been achieved by providing empirical evidence as indicated in chapter four, where it shows that participants believe that decentralisation promotes efficiency and SETAs in the Province of the Eastern Cape are not granted discretionary powers to make decisions a primary reason that leads to delays being experienced. This lack of discretionary power is proof that decision-making is still centralised. The study has the following strategies for the SETAs in the Province of the Eastern Cape to carry out their skills development mandate: - Clear strategic intent about SETA provincial offices; - Sector Skills Plans (SSP) to reflect provincial focus; - Provincial offices to exercise some discretionary powers; - Adequate financial resources; - Skilled workforce. In order to be more effective and efficient, a variety of recommendations to SETAs, with respect to decentralisation of SETAs, were made. It is hoped that these recommendations assist in improvement of the implementation of a decentralisation strategy. More importantly decentralisation of SETAs should allow and enable branch offices to exercise discretionary powers. In addition, they should have adequate financial resources to manage their affairs.
- Full Text:
- Date Issued: 2010
- Authors: Gazi, Luvo Ndileka
- Date: 2010
- Subjects: Schools -- Decentralization -- South Africa -- Eastern Cape , School management and organization -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: vital:8193 , http://hdl.handle.net/10948/1346 , Schools -- Decentralization -- South Africa -- Eastern Cape , School management and organization -- South Africa -- Eastern Cape
- Description: It is largely believed that decentralisation promotes efficiency in organisations. This paper analyses the challenges facing decentralisation of Sector Education and Training Authorities (SETAs) in the Province of the Eastern Cape. It is demonstrated that the form of decentralisation followed by SETAs in the Province of the Eastern Cape, where constant referral of matters to head offices for decisions and instruction before any action is taken, by them is the biggest challenge. Yet these important institutions are mandated by government to equip South Africans with skills to enable them to succeed in the global market and to offer opportunities to individuals and communities for self advancement and to play a productive role in society are frustrated by unnecessary interference from SETA national offices on their affairs at the provincial government level, which constrains effective decentralisation. However, the objectives of the study are to: - Analyse the challenges of decentralisation by SETAs in the Province of the Eastern Cape; - Provide an overview of the impact of SETA provincial offices on requisite skills in the province; - Investigate the advantages and disadvantages of decentralising SETAs in the provinces. These objectives have been achieved by providing empirical evidence as indicated in chapter four, where it shows that participants believe that decentralisation promotes efficiency and SETAs in the Province of the Eastern Cape are not granted discretionary powers to make decisions a primary reason that leads to delays being experienced. This lack of discretionary power is proof that decision-making is still centralised. The study has the following strategies for the SETAs in the Province of the Eastern Cape to carry out their skills development mandate: - Clear strategic intent about SETA provincial offices; - Sector Skills Plans (SSP) to reflect provincial focus; - Provincial offices to exercise some discretionary powers; - Adequate financial resources; - Skilled workforce. In order to be more effective and efficient, a variety of recommendations to SETAs, with respect to decentralisation of SETAs, were made. It is hoped that these recommendations assist in improvement of the implementation of a decentralisation strategy. More importantly decentralisation of SETAs should allow and enable branch offices to exercise discretionary powers. In addition, they should have adequate financial resources to manage their affairs.
- Full Text:
- Date Issued: 2010
An exploration of father-child relationships, current attachment styles and self-esteem amongst adults
- Authors: Williams, Clare Marianne
- Date: 2006
- Subjects: Attachment behavior -- South Africa , Attachment behavior in children -- South Africa , Father and child -- South Africa , Self-esteem in men -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9855 , http://hdl.handle.net/10948/398 , Attachment behavior -- South Africa , Attachment behavior in children -- South Africa , Father and child -- South Africa , Self-esteem in men -- South Africa
- Description: This study explored and described the relationship between early attachment to the father figure and self-esteem and current adult attachment style. Specifically, the present study explored and described the impact of the internal working model of early paternal attachment upon adult attachment styles and levels of self-esteem. The data for this study was obtained by utilizing the following four questionnaires: The Inventory of Parent and Peer Attachment (IPPA) Part 2 as a retrospective measure, the Relationship Questionnaire (RQ), Relationship Scales Questionnaire (RSQ) and Battle’s Culture Free Self-Esteem Inventory (CFSEI). An exploratory descriptive design using a non-probability, convenience sampling method was employed for the present study. A sample of 105 adult participants from a religious institution within Port Elizabeth was selected. Participants, including both males and females, representative of all cultures and socio-economic status, were interviewed using the above self-report measures. The data for this study was analyzed using descriptive and correlational and inferential statistics. The findings indicated that the majority of the sample had a preoccupied attachment style, with Intermediate self-esteem levels.
- Full Text:
- Date Issued: 2006
- Authors: Williams, Clare Marianne
- Date: 2006
- Subjects: Attachment behavior -- South Africa , Attachment behavior in children -- South Africa , Father and child -- South Africa , Self-esteem in men -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9855 , http://hdl.handle.net/10948/398 , Attachment behavior -- South Africa , Attachment behavior in children -- South Africa , Father and child -- South Africa , Self-esteem in men -- South Africa
- Description: This study explored and described the relationship between early attachment to the father figure and self-esteem and current adult attachment style. Specifically, the present study explored and described the impact of the internal working model of early paternal attachment upon adult attachment styles and levels of self-esteem. The data for this study was obtained by utilizing the following four questionnaires: The Inventory of Parent and Peer Attachment (IPPA) Part 2 as a retrospective measure, the Relationship Questionnaire (RQ), Relationship Scales Questionnaire (RSQ) and Battle’s Culture Free Self-Esteem Inventory (CFSEI). An exploratory descriptive design using a non-probability, convenience sampling method was employed for the present study. A sample of 105 adult participants from a religious institution within Port Elizabeth was selected. Participants, including both males and females, representative of all cultures and socio-economic status, were interviewed using the above self-report measures. The data for this study was analyzed using descriptive and correlational and inferential statistics. The findings indicated that the majority of the sample had a preoccupied attachment style, with Intermediate self-esteem levels.
- Full Text:
- Date Issued: 2006
An analysis of the views of journalists and government officials regarding the impact of new vision's coverage of the Nakivubo Channel Rehabilitation Project
- Authors: Kaheru, Hamis
- Date: 2005
- Subjects: Nakivubo Urban Wetland (Uganda) , Nakivubo Channel Rehabilitation Project , New Vision (Uganda) , Environmental protection -- Press coverage -- Uganda , Government and the press -- Uganda
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3439 , http://hdl.handle.net/10962/d1002893 , Nakivubo Urban Wetland (Uganda) , Nakivubo Channel Rehabilitation Project , New Vision (Uganda) , Environmental protection -- Press coverage -- Uganda , Government and the press -- Uganda
- Full Text:
- Date Issued: 2005
- Authors: Kaheru, Hamis
- Date: 2005
- Subjects: Nakivubo Urban Wetland (Uganda) , Nakivubo Channel Rehabilitation Project , New Vision (Uganda) , Environmental protection -- Press coverage -- Uganda , Government and the press -- Uganda
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3439 , http://hdl.handle.net/10962/d1002893 , Nakivubo Urban Wetland (Uganda) , Nakivubo Channel Rehabilitation Project , New Vision (Uganda) , Environmental protection -- Press coverage -- Uganda , Government and the press -- Uganda
- Full Text:
- Date Issued: 2005
Brian Bradshaw
- Authors: Hogge, Rosemary
- Date: 1976
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2506 , http://hdl.handle.net/10962/d1016168
- Description: One assumes that Brian Bradshaw's career in art had been decided upon at an early age, but in fact it was not so. After he had attended the Canon Slade Grammar School in Bolton, his father suggested various options, some of them interesting, like becoming a veterinary surgeon, but that was rejected because although the boy liked 'putting things right' he didn't savour 'cutting things up'. For the same reason he couldn't follow the family tradition on his mother's side and become a doctor. Nor was his wish to become a sea-captain treated with any seriousness, although he thinks with nostalgia of life at sea; and he is pleased he didn't take up forestry because, although he loves the land and admires the art of designing the great gardens and parks which surrounded the Georgian and Regency houses of the 18th Century, he is appalled by the artificial mess they're making of the land now. So in that interim period before being conscripted, they suggested at home that he spend a few months at the Bolton Municipal School of Art under the guidance of Mr. John R. Gauld, and so his course was set for the future. He studied there for three years and was successful in obtaining the "drawing" and "pictorial design" certificates of the Ministry of Education, before joining His Majesty's Forces in 1942.
- Full Text:
- Date Issued: 1976
- Authors: Hogge, Rosemary
- Date: 1976
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2506 , http://hdl.handle.net/10962/d1016168
- Description: One assumes that Brian Bradshaw's career in art had been decided upon at an early age, but in fact it was not so. After he had attended the Canon Slade Grammar School in Bolton, his father suggested various options, some of them interesting, like becoming a veterinary surgeon, but that was rejected because although the boy liked 'putting things right' he didn't savour 'cutting things up'. For the same reason he couldn't follow the family tradition on his mother's side and become a doctor. Nor was his wish to become a sea-captain treated with any seriousness, although he thinks with nostalgia of life at sea; and he is pleased he didn't take up forestry because, although he loves the land and admires the art of designing the great gardens and parks which surrounded the Georgian and Regency houses of the 18th Century, he is appalled by the artificial mess they're making of the land now. So in that interim period before being conscripted, they suggested at home that he spend a few months at the Bolton Municipal School of Art under the guidance of Mr. John R. Gauld, and so his course was set for the future. He studied there for three years and was successful in obtaining the "drawing" and "pictorial design" certificates of the Ministry of Education, before joining His Majesty's Forces in 1942.
- Full Text:
- Date Issued: 1976
Effects of precipitating electrons in the ionosphere
- Authors: Haschick, Aubrey D
- Date: 1974
- Subjects: Electrons , Electron precipitation , Ionosphere , Ionospheric electron density
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5526 , http://hdl.handle.net/10962/d1012220
- Description: As early as 1896, around the time of the discovery of the electron by J.J. Thompson, Birkeland was led to propose that aurorae were caused by fast moving electrons or similarly charged particles emitted by the sun and 'sucked in towards' the auroral zones by the geomagnetic field. He later supported this idea by firing electrons at a dipole field surrounding a sphere covered with a fluorescent coating. Extensive ground based observations of auroral features eventually led, in 1950, to the initial direct evidence of the fact that auroral emissions are due to energetic charged particles, consisting partly of protons, entering the earth's atmosphere (Meinel, 1951). However, it was only in 1952 and 1953 that the first measurements of what was later interpreted as bremsstrahlung X- rays from precipitating electrons were made at auroral latitudes. (Meredith et aI, 1955) During the IGY, 1957 - 1958, a number of rockets were fired through and near, visible aurorae and large fluxes of low energy electrons were detected ... Intro., p. 1.
- Full Text:
- Date Issued: 1974
- Authors: Haschick, Aubrey D
- Date: 1974
- Subjects: Electrons , Electron precipitation , Ionosphere , Ionospheric electron density
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5526 , http://hdl.handle.net/10962/d1012220
- Description: As early as 1896, around the time of the discovery of the electron by J.J. Thompson, Birkeland was led to propose that aurorae were caused by fast moving electrons or similarly charged particles emitted by the sun and 'sucked in towards' the auroral zones by the geomagnetic field. He later supported this idea by firing electrons at a dipole field surrounding a sphere covered with a fluorescent coating. Extensive ground based observations of auroral features eventually led, in 1950, to the initial direct evidence of the fact that auroral emissions are due to energetic charged particles, consisting partly of protons, entering the earth's atmosphere (Meinel, 1951). However, it was only in 1952 and 1953 that the first measurements of what was later interpreted as bremsstrahlung X- rays from precipitating electrons were made at auroral latitudes. (Meredith et aI, 1955) During the IGY, 1957 - 1958, a number of rockets were fired through and near, visible aurorae and large fluxes of low energy electrons were detected ... Intro., p. 1.
- Full Text:
- Date Issued: 1974
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