The roles of black-backed jackals and caracals in issues of human-wildlife conflict in the Eastern Cape, South Africa
- Authors: Murison, Megan Kate
- Date: 2015
- Subjects: Black-backed jackal -- South Africa -- Eastern Cape , Human-animal relationships -- South Africa -- Eastern Cape , Predatory animals -- Control -- South Africa -- Eastern Cape , Black-backed jackal -- Food -- South Africa -- Eastern Cape , Black-backed jackal -- Effect of human beings on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5939 , http://hdl.handle.net/10962/d1018667
- Description: [Partial abstract]: Human-wildlife conflict is a widely observed phenomenon and encompasses a range of negative interactions between humans and wildlife. Depredation upon livestock and game species proves to be the prevalent form of this conflict and often results in the killing of carnivores. Within the South African context, despite intense lethal control, two sympatric mesopredators, the blackbacked jackal (Canis mesomelas) and the caracal (Caracal caracal), remain common enough to be considered a major threat to human livelihoods through depredation. Wildlife ranches and livestock farms dominate the landscape in the Eastern Cape Province. Moreover, human-predator conflict within the region is extensive as both the black-backed jackal and caracal are seen to be inimical by landowners. Understanding this conflict is essential for mitigating any potential adverse environmental reactions (i.e. range collapses or extinctions) and requires knowledge of anthropogenic, ecological and environmental factors. I interviewed 73 land owners across five municipal boundaries in the Eastern Cape to quantify perceptions of predator control methods.
- Full Text:
- Date Issued: 2015
- Authors: Murison, Megan Kate
- Date: 2015
- Subjects: Black-backed jackal -- South Africa -- Eastern Cape , Human-animal relationships -- South Africa -- Eastern Cape , Predatory animals -- Control -- South Africa -- Eastern Cape , Black-backed jackal -- Food -- South Africa -- Eastern Cape , Black-backed jackal -- Effect of human beings on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5939 , http://hdl.handle.net/10962/d1018667
- Description: [Partial abstract]: Human-wildlife conflict is a widely observed phenomenon and encompasses a range of negative interactions between humans and wildlife. Depredation upon livestock and game species proves to be the prevalent form of this conflict and often results in the killing of carnivores. Within the South African context, despite intense lethal control, two sympatric mesopredators, the blackbacked jackal (Canis mesomelas) and the caracal (Caracal caracal), remain common enough to be considered a major threat to human livelihoods through depredation. Wildlife ranches and livestock farms dominate the landscape in the Eastern Cape Province. Moreover, human-predator conflict within the region is extensive as both the black-backed jackal and caracal are seen to be inimical by landowners. Understanding this conflict is essential for mitigating any potential adverse environmental reactions (i.e. range collapses or extinctions) and requires knowledge of anthropogenic, ecological and environmental factors. I interviewed 73 land owners across five municipal boundaries in the Eastern Cape to quantify perceptions of predator control methods.
- Full Text:
- Date Issued: 2015
The role of Hsp90/Hsp70 organising protein (Hop) in the Proliferation, Survival and Migration of Breast Cancer Cells.
- Authors: Willmer, Tarryn
- Date: 2012
- Subjects: Cancer -- Treatment , Heat shock proteins , Cancer cells , Breast -- Cancer
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4130 , http://hdl.handle.net/10962/d1015720
- Description: Hop (the Hsp90/Hsp70 organising protein) is a co-chaperone that acts as an adapter between the major molecular chaperones Hsp90 and Hsp70 during the cellular assembly of the Hsp90 complex. The Hsp90 complex regulates the stability and conformational maturation of a range of important cellular proteins, many of which are deregulated in cancer. In this study, we hypothesised that Hop knockdown inhibits proliferation and migration of cancer cells. We characterised the expression of Hop in cell models of different cancerous status, and provided evidence that Hop was upregulated in tumour cells compared to normal cell counterparts. Using an RNA interference approach, a 60-90% knockdown of Hop was achieved for up to 144 hours in the MDA-MB-231 and Hs578T breast cancer cell lines. Hop knockdown resulted in downregulation of the Hsp90 client proteins, Akt and Stat3, as well as a change in the expression of other Hsp90 co-chaperones, p23, Cdc37 and Aha1, while no change in the levels of Hsp90 or Hsp70 was observed. Silencing of Hop impaired cell proliferation in Hs578T cells but an increase in proliferation in MDA-MB-231, suggesting that the role of Hop in cancer cell proliferation was dependent on type of cancer cell. Hop knockdown in Hs578T and MDA-MB- 231 cells did not lead to any significant changes in the half maximal inhibitory concentrations (IC50) of selected small molecule inhibitors (paclitaxel, geldanamycin and novobiocin) in these cell lines after 72 hours. Hop knockdown cells were however, more sensitive than control cells to the Hsp90 inhibitors geldanamycin and novobiocin at earlier time points and in the presence of the drug transporter inhibitor, verapamil. Hop knockdown caused a decrease in cell migration as measured by the wound healing assay in both Hs578T and MDA-MB-231 cells. Hop was present in purified pseudopodia fractions of migrating cells, and immunofluorescence analysis showed that Hop colocalised with actin at the leading edges of pseudopodia, points of adhesion and at intercellular junctions of cells that have been stimulated to migrate with the chemokine stromal derived factor-1. Hop was able to bind to actin in vitro using actin cosedimentation assays, and silencing of Hop dramatically reduced the capacity of Hs578T cells to form pseudopodia. These results establish a correlation between Hop and actin dynamics, pseudopodia formation and migration in the context of Hop silencing, and collectively suggest that Hop plays a role in cancer cell migration. This study presents experimental evidence for a promising alternative to targeting Hsp90 and Hsp70 chaperones, a novel drug target in cancer therapy.
- Full Text:
- Date Issued: 2012
- Authors: Willmer, Tarryn
- Date: 2012
- Subjects: Cancer -- Treatment , Heat shock proteins , Cancer cells , Breast -- Cancer
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4130 , http://hdl.handle.net/10962/d1015720
- Description: Hop (the Hsp90/Hsp70 organising protein) is a co-chaperone that acts as an adapter between the major molecular chaperones Hsp90 and Hsp70 during the cellular assembly of the Hsp90 complex. The Hsp90 complex regulates the stability and conformational maturation of a range of important cellular proteins, many of which are deregulated in cancer. In this study, we hypothesised that Hop knockdown inhibits proliferation and migration of cancer cells. We characterised the expression of Hop in cell models of different cancerous status, and provided evidence that Hop was upregulated in tumour cells compared to normal cell counterparts. Using an RNA interference approach, a 60-90% knockdown of Hop was achieved for up to 144 hours in the MDA-MB-231 and Hs578T breast cancer cell lines. Hop knockdown resulted in downregulation of the Hsp90 client proteins, Akt and Stat3, as well as a change in the expression of other Hsp90 co-chaperones, p23, Cdc37 and Aha1, while no change in the levels of Hsp90 or Hsp70 was observed. Silencing of Hop impaired cell proliferation in Hs578T cells but an increase in proliferation in MDA-MB-231, suggesting that the role of Hop in cancer cell proliferation was dependent on type of cancer cell. Hop knockdown in Hs578T and MDA-MB- 231 cells did not lead to any significant changes in the half maximal inhibitory concentrations (IC50) of selected small molecule inhibitors (paclitaxel, geldanamycin and novobiocin) in these cell lines after 72 hours. Hop knockdown cells were however, more sensitive than control cells to the Hsp90 inhibitors geldanamycin and novobiocin at earlier time points and in the presence of the drug transporter inhibitor, verapamil. Hop knockdown caused a decrease in cell migration as measured by the wound healing assay in both Hs578T and MDA-MB-231 cells. Hop was present in purified pseudopodia fractions of migrating cells, and immunofluorescence analysis showed that Hop colocalised with actin at the leading edges of pseudopodia, points of adhesion and at intercellular junctions of cells that have been stimulated to migrate with the chemokine stromal derived factor-1. Hop was able to bind to actin in vitro using actin cosedimentation assays, and silencing of Hop dramatically reduced the capacity of Hs578T cells to form pseudopodia. These results establish a correlation between Hop and actin dynamics, pseudopodia formation and migration in the context of Hop silencing, and collectively suggest that Hop plays a role in cancer cell migration. This study presents experimental evidence for a promising alternative to targeting Hsp90 and Hsp70 chaperones, a novel drug target in cancer therapy.
- Full Text:
- Date Issued: 2012
An empirical investigation into the determinants of stock market behaviour in South Africa
- Authors: Olalere, Durodola Oludamola
- Date: 2007
- Subjects: Johannesburg Stock Exchange , Stocks -- Prices -- South Africa , Stock exchanges -- South Africa , Macroeconomics -- South Africa , Interest rates -- South Africa , Foreign exchange rates -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:998 , http://hdl.handle.net/10962/d1002733 , Johannesburg Stock Exchange , Stocks -- Prices -- South Africa , Stock exchanges -- South Africa , Macroeconomics -- South Africa , Interest rates -- South Africa , Foreign exchange rates -- South Africa
- Description: The argument with regards to whether macro-economic fundamentals determine stock market behaviour is very important because of the roles it plays in an economy. Such roles include: pooling and trading of risks, mobilization of savings, provision of liquidity and allocation of capital. However, the stock market will only perform such roles effectively if the macro-economic environment is conducive. This study examined the behaviour of the All Share Index (ALSI) and market capitalization on the Johannesburg Stock Exchange in response to changes in the domestic and international macro-economic fundamentals such as the consumer price index, rand-dollar real exchange rates, domestic GDP, yield on South African government bonds, yield on United States government bonds and United States GDP. The study used cointegration and error correction techniques proposed by Johansen and Juselius (1990) to test for long run relationship. Two separate models were estimated and results obtained show that the two proxies for the stock market behaviour (All share Index and market capitalization) are true endogenous variables, but react differently to economic fundamentals. The consumer price index has a significant negative impact on the JSE share price index while market capitalization is determined predominantly by the yield on South African government bonds. The exchange rate seems to have had little or no influence on the share price index, but becomes negative and significant in the case of market capitalization. The yield on United States government bonds also produced a strong influence on both the share price index and market capitalization. While it has a negative significant impact on share prices, it produced a positive significant impact on market capitalization. In order to ascertain whether the South African interest rate or the United States interest rate is more important in explaining the share price and market capitalization, each of the variables were estimated in the model separately, the result obtained reveals that the United States interest rate is more important than the domestic interest rate in explaining the share price and market capitalization on the JSE. This implies that investors need to observe the USA interest rate before investing in South African equities. A comparison of the responses of share price index and market capitalization to impulses from the macro-economic variables tested reveals that both proxies elicit a positive response from aggregate output. The share price index responds more significantly to impulses from output growth than the market capitalization, meaning that, as aggregate production increases, the share price index tends to respond positively and quickly. The exchange rate produced mixed result from the two proxies, while it produced a positive response from the market capitalization; an initial positive response was noted in the share price index that immediately turned negative. Another glaring contrast was identified in the response of both proxies to impulses from the United States interest rate. The share price index responded positively while the market capitalization produced a negative response. This finding reveals that the two proxies actually respond differently to macro-economic variables. The variance decomposition of both stock prices and market capitalization reveals that the yield on United States government bonds has a more significant absorption potential than the South African government bonds. However, the absorption process is slower in the case of the market capitalization. The exchange rate has a greater impact on the market capitalization than stock prices. The overall assessment shows that share prices respond faster than market capitalization to macro-economic fundamentals. The study also shows that the increased openness of the South African economy by way of relaxation of the exchange control on capital account transaction has allowed the USA market to play a crucial role in equity prices in South Africa. Three main policy recommendations results from the study. Firstly, if inflation is well monitored, then the local equity market is bound to perform strongly resulting in strong shares earning growth. Secondly, the exchange rate should be made to be less volatile so that long term investment plans across borders can be further enhanced. Thirdly, financial analyst and investors in South Africa need to analyse macro-economic developments in the United States before investing in equities in South Africa.
- Full Text:
- Date Issued: 2007
- Authors: Olalere, Durodola Oludamola
- Date: 2007
- Subjects: Johannesburg Stock Exchange , Stocks -- Prices -- South Africa , Stock exchanges -- South Africa , Macroeconomics -- South Africa , Interest rates -- South Africa , Foreign exchange rates -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:998 , http://hdl.handle.net/10962/d1002733 , Johannesburg Stock Exchange , Stocks -- Prices -- South Africa , Stock exchanges -- South Africa , Macroeconomics -- South Africa , Interest rates -- South Africa , Foreign exchange rates -- South Africa
- Description: The argument with regards to whether macro-economic fundamentals determine stock market behaviour is very important because of the roles it plays in an economy. Such roles include: pooling and trading of risks, mobilization of savings, provision of liquidity and allocation of capital. However, the stock market will only perform such roles effectively if the macro-economic environment is conducive. This study examined the behaviour of the All Share Index (ALSI) and market capitalization on the Johannesburg Stock Exchange in response to changes in the domestic and international macro-economic fundamentals such as the consumer price index, rand-dollar real exchange rates, domestic GDP, yield on South African government bonds, yield on United States government bonds and United States GDP. The study used cointegration and error correction techniques proposed by Johansen and Juselius (1990) to test for long run relationship. Two separate models were estimated and results obtained show that the two proxies for the stock market behaviour (All share Index and market capitalization) are true endogenous variables, but react differently to economic fundamentals. The consumer price index has a significant negative impact on the JSE share price index while market capitalization is determined predominantly by the yield on South African government bonds. The exchange rate seems to have had little or no influence on the share price index, but becomes negative and significant in the case of market capitalization. The yield on United States government bonds also produced a strong influence on both the share price index and market capitalization. While it has a negative significant impact on share prices, it produced a positive significant impact on market capitalization. In order to ascertain whether the South African interest rate or the United States interest rate is more important in explaining the share price and market capitalization, each of the variables were estimated in the model separately, the result obtained reveals that the United States interest rate is more important than the domestic interest rate in explaining the share price and market capitalization on the JSE. This implies that investors need to observe the USA interest rate before investing in South African equities. A comparison of the responses of share price index and market capitalization to impulses from the macro-economic variables tested reveals that both proxies elicit a positive response from aggregate output. The share price index responds more significantly to impulses from output growth than the market capitalization, meaning that, as aggregate production increases, the share price index tends to respond positively and quickly. The exchange rate produced mixed result from the two proxies, while it produced a positive response from the market capitalization; an initial positive response was noted in the share price index that immediately turned negative. Another glaring contrast was identified in the response of both proxies to impulses from the United States interest rate. The share price index responded positively while the market capitalization produced a negative response. This finding reveals that the two proxies actually respond differently to macro-economic variables. The variance decomposition of both stock prices and market capitalization reveals that the yield on United States government bonds has a more significant absorption potential than the South African government bonds. However, the absorption process is slower in the case of the market capitalization. The exchange rate has a greater impact on the market capitalization than stock prices. The overall assessment shows that share prices respond faster than market capitalization to macro-economic fundamentals. The study also shows that the increased openness of the South African economy by way of relaxation of the exchange control on capital account transaction has allowed the USA market to play a crucial role in equity prices in South Africa. Three main policy recommendations results from the study. Firstly, if inflation is well monitored, then the local equity market is bound to perform strongly resulting in strong shares earning growth. Secondly, the exchange rate should be made to be less volatile so that long term investment plans across borders can be further enhanced. Thirdly, financial analyst and investors in South Africa need to analyse macro-economic developments in the United States before investing in equities in South Africa.
- Full Text:
- Date Issued: 2007
Protecting depositors and promoting financial stability in South Africa : is there a case for the introduction of deposit insurance?
- Authors: Ngaujake, Uahatjiri
- Date: 2004
- Subjects: Banks and banking -- South Africa , Bank deposits -- South Africa , Bank failures , Banks and banking -- State supervision , Deposit insurance , Consumer protection -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1025 , http://hdl.handle.net/10962/d1002760 , Banks and banking -- South Africa , Bank deposits -- South Africa , Bank failures , Banks and banking -- State supervision , Deposit insurance , Consumer protection -- South Africa
- Description: Banks play a pivotal role in economic growth and development of all countries and therefore the stability of the banking system is a vital goal of bank supervisors. Banks act as delegated monitors of depositors’ funds and this relationship, like all principal-agent relationships, presents agency problems. In the case of banks agency problems arise because depositors cannot accurately assess the financial health of banks due to the asymmetry of information existing between banks and depositors. Because banks possess private information on their borrowers, which depositors cannot access, it exposes depositors to risk of loss of deposits in cases of bank failures originating from nonrepayment of such loans. This asymmetry of information also exposes banks to runs by depositors and these runs can lead to bank failures with devastating effects for the financial system and the economy at large. It is for this reason that banks are regulated and supervised more than other institutions. Bank failures are a worldwide phenomenon and South Africa is no exception as evidenced by historical and recent bank failures in South Africa. This thesis investigates the desirability of introducing an explicit deposit insurance scheme in South Africa as a means of protecting small, unsophisticated depositors who are almost always the losers when banks fail, and promoting financial stability. The study finds that bank failures in South Africa are mainly attributable to mismanagement of banks, liquidity problems and fraud. Bank failures as a result of the aforementioned reasons have led to depositors losing their deposits in South Africa. The absence of a clearly defined depositor protection scheme in South Africa, the inadequacy of the hitherto implicit guarantee system to protect depositors, and the poor record of the South African Reserve Bank in bank failure resolution, form the basis of the conclusion of the study, i.e., there is a case for the introduction of deposit insurance in South Africa. In order to assist South African policymakers in designing an effective deposit insurance scheme for the country, the thesis further provides a guide on how the most important design features of deposit insurance should be handled. This is in an attempt to ensure that the moral hazard problem inherent in deposit insurance is overcome.
- Full Text:
- Date Issued: 2004
- Authors: Ngaujake, Uahatjiri
- Date: 2004
- Subjects: Banks and banking -- South Africa , Bank deposits -- South Africa , Bank failures , Banks and banking -- State supervision , Deposit insurance , Consumer protection -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1025 , http://hdl.handle.net/10962/d1002760 , Banks and banking -- South Africa , Bank deposits -- South Africa , Bank failures , Banks and banking -- State supervision , Deposit insurance , Consumer protection -- South Africa
- Description: Banks play a pivotal role in economic growth and development of all countries and therefore the stability of the banking system is a vital goal of bank supervisors. Banks act as delegated monitors of depositors’ funds and this relationship, like all principal-agent relationships, presents agency problems. In the case of banks agency problems arise because depositors cannot accurately assess the financial health of banks due to the asymmetry of information existing between banks and depositors. Because banks possess private information on their borrowers, which depositors cannot access, it exposes depositors to risk of loss of deposits in cases of bank failures originating from nonrepayment of such loans. This asymmetry of information also exposes banks to runs by depositors and these runs can lead to bank failures with devastating effects for the financial system and the economy at large. It is for this reason that banks are regulated and supervised more than other institutions. Bank failures are a worldwide phenomenon and South Africa is no exception as evidenced by historical and recent bank failures in South Africa. This thesis investigates the desirability of introducing an explicit deposit insurance scheme in South Africa as a means of protecting small, unsophisticated depositors who are almost always the losers when banks fail, and promoting financial stability. The study finds that bank failures in South Africa are mainly attributable to mismanagement of banks, liquidity problems and fraud. Bank failures as a result of the aforementioned reasons have led to depositors losing their deposits in South Africa. The absence of a clearly defined depositor protection scheme in South Africa, the inadequacy of the hitherto implicit guarantee system to protect depositors, and the poor record of the South African Reserve Bank in bank failure resolution, form the basis of the conclusion of the study, i.e., there is a case for the introduction of deposit insurance in South Africa. In order to assist South African policymakers in designing an effective deposit insurance scheme for the country, the thesis further provides a guide on how the most important design features of deposit insurance should be handled. This is in an attempt to ensure that the moral hazard problem inherent in deposit insurance is overcome.
- Full Text:
- Date Issued: 2004
Screening of the white margined sole, Synaptura marginata (Soleidae), as a candidate for aquaculture in South Africa
- Authors: Thompson, Ernst Frederick
- Date: 2004
- Subjects: Flatfishes -- South Africa , Aquaculture -- South Africa , Soleidae -- South Africa , Soleidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5207 , http://hdl.handle.net/10962/d1004523 , Flatfishes -- South Africa , Aquaculture -- South Africa , Soleidae -- South Africa , Soleidae
- Description: The white margined sole Synaptura marginata (Soleidae) was isolated as the most likely candidate for flatfish aquaculture in South Africa. The aim of the study was to screen the sole as a candidate aquaculture species by way of a comprehensive study of its biology and life history strategy and to identify possible "bottlenecks". The study was undertaken on the assumption that the biological data would provide valuable information for developing specific technologies that might be required for the farming of this species. Specimens were collected monthly by spearing along the Eastern Cape coast of South Africa between December 2000 and March 2002. Length-at-age data required for modeling the growth of S. marginata was obtained from sectioned otoliths. A Von Bertalanffy growth model with an absolute error structure best describes the growth for this species. The model parameters were: L∞ = 429.5 mm TL, K = 0.24 and t₀ = -1 .79 years. Analysis of gut contents showed that S. marginata feed exclusively on polychaete worms, mainly of the genus Morphysa. S. marginata shows a protracted summer spawning season of six months, from October to April. This was determined by the calculation of a monthly gonadosomatic index and a macroscopic maturity scale. Histological examination of the ovaries revealed five ovarian developmental stages. Size at 50% and 100% sexual maturity for females was calculated to be 235 mm TL and 300 mm TL (ca. 1.5 - 2.5 years of age) and all males> 154 mm TL were mature. S. marginata is a batch spawner, releasing a minimum of 3 batches of eggs per year. Relative fecundity is high (34000 eggs per year I kg) and this coupled with the protracted spawning season would make it possible to obtain adequate numbers of juveniles (for farming) for approximately five to six months of the year. Comparative analysis of the biological characteristics in relation to other soles farmed elsewhere in the world suggests that S. marginata is a suitable candidate for marine fish culture in South Africa.
- Full Text:
- Date Issued: 2004
- Authors: Thompson, Ernst Frederick
- Date: 2004
- Subjects: Flatfishes -- South Africa , Aquaculture -- South Africa , Soleidae -- South Africa , Soleidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5207 , http://hdl.handle.net/10962/d1004523 , Flatfishes -- South Africa , Aquaculture -- South Africa , Soleidae -- South Africa , Soleidae
- Description: The white margined sole Synaptura marginata (Soleidae) was isolated as the most likely candidate for flatfish aquaculture in South Africa. The aim of the study was to screen the sole as a candidate aquaculture species by way of a comprehensive study of its biology and life history strategy and to identify possible "bottlenecks". The study was undertaken on the assumption that the biological data would provide valuable information for developing specific technologies that might be required for the farming of this species. Specimens were collected monthly by spearing along the Eastern Cape coast of South Africa between December 2000 and March 2002. Length-at-age data required for modeling the growth of S. marginata was obtained from sectioned otoliths. A Von Bertalanffy growth model with an absolute error structure best describes the growth for this species. The model parameters were: L∞ = 429.5 mm TL, K = 0.24 and t₀ = -1 .79 years. Analysis of gut contents showed that S. marginata feed exclusively on polychaete worms, mainly of the genus Morphysa. S. marginata shows a protracted summer spawning season of six months, from October to April. This was determined by the calculation of a monthly gonadosomatic index and a macroscopic maturity scale. Histological examination of the ovaries revealed five ovarian developmental stages. Size at 50% and 100% sexual maturity for females was calculated to be 235 mm TL and 300 mm TL (ca. 1.5 - 2.5 years of age) and all males> 154 mm TL were mature. S. marginata is a batch spawner, releasing a minimum of 3 batches of eggs per year. Relative fecundity is high (34000 eggs per year I kg) and this coupled with the protracted spawning season would make it possible to obtain adequate numbers of juveniles (for farming) for approximately five to six months of the year. Comparative analysis of the biological characteristics in relation to other soles farmed elsewhere in the world suggests that S. marginata is a suitable candidate for marine fish culture in South Africa.
- Full Text:
- Date Issued: 2004
Minor "dings" - major effects? a study into the cognitive effects of mild head injuries in high school rugby
- Authors: Ackermann, Tessa Ruth
- Date: 2000
- Subjects: Rugby football injuries , Head -- Wounds and injuries -- Psychology , Head -- Wounds and injuries -- Complications , Head -- Wounds and injuries -- Patients -- Rehabilitation
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2920 , http://hdl.handle.net/10962/d1002429 , Rugby football injuries , Head -- Wounds and injuries -- Psychology , Head -- Wounds and injuries -- Complications , Head -- Wounds and injuries -- Patients -- Rehabilitation
- Description: The present study is part of a larger and ongoing research initiative investigating the cumulative cognitive effects of mild head injury in rugby union and focused specifically on high school rugby players. A comprehensive battery of neuropsychological tests was administered to top team high school rugby players (n = 47), and a non-contact sport control group of top team high school hockey players (n = 34). Direct comparisons of group mean scores and standard deviations across each neuropsychological test were carried out for the Total Rugby group versus the Total Hockey group as well as for the subgroups Rugby Forwards versus Rugby Backs. A correlational analysis was conducted to ascertain whether a relationship exists between the number of mild head injuries reported by the players and their cognitive test performance. Results of the group comparisons of means and variability on WMS Paired Associate Learning Hard Pairs - Delayed Recall provides tentative indications of the initial stages of diffuse damage associated with mild head injury in the rugby group and provides some evidence for impairment of verbal learning and memory in the Rugby Forwards group. The correlational analysis revealed no significant relationship between number of reported mild head injuries and cognitive performance. The findings and possible latent effects of the multiple mild head injuries reported by the rugby players are discussed in terms of brain reserve capacity theory and suggestions for future research are provided.
- Full Text:
- Date Issued: 2000
- Authors: Ackermann, Tessa Ruth
- Date: 2000
- Subjects: Rugby football injuries , Head -- Wounds and injuries -- Psychology , Head -- Wounds and injuries -- Complications , Head -- Wounds and injuries -- Patients -- Rehabilitation
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2920 , http://hdl.handle.net/10962/d1002429 , Rugby football injuries , Head -- Wounds and injuries -- Psychology , Head -- Wounds and injuries -- Complications , Head -- Wounds and injuries -- Patients -- Rehabilitation
- Description: The present study is part of a larger and ongoing research initiative investigating the cumulative cognitive effects of mild head injury in rugby union and focused specifically on high school rugby players. A comprehensive battery of neuropsychological tests was administered to top team high school rugby players (n = 47), and a non-contact sport control group of top team high school hockey players (n = 34). Direct comparisons of group mean scores and standard deviations across each neuropsychological test were carried out for the Total Rugby group versus the Total Hockey group as well as for the subgroups Rugby Forwards versus Rugby Backs. A correlational analysis was conducted to ascertain whether a relationship exists between the number of mild head injuries reported by the players and their cognitive test performance. Results of the group comparisons of means and variability on WMS Paired Associate Learning Hard Pairs - Delayed Recall provides tentative indications of the initial stages of diffuse damage associated with mild head injury in the rugby group and provides some evidence for impairment of verbal learning and memory in the Rugby Forwards group. The correlational analysis revealed no significant relationship between number of reported mild head injuries and cognitive performance. The findings and possible latent effects of the multiple mild head injuries reported by the rugby players are discussed in terms of brain reserve capacity theory and suggestions for future research are provided.
- Full Text:
- Date Issued: 2000
A review of Southern African kimberlites and exploration techniques
- Authors: Venter, Louis Johannes
- Date: 1999 , 2013-10-04
- Subjects: Kimberlite -- Africa, Southern , Diamonds -- Africa, Southern , Prospecting -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5033 , http://hdl.handle.net/10962/d1007278 , Kimberlite -- Africa, Southern , Diamonds -- Africa, Southern , Prospecting -- South Africa
- Description: The dissertation reviews the present knowledge regarding diamonds, from its formation in the lithospheric upper mantle at depths between 150 and 300 km, to its final valuation in terms of US$/carat by diamantaires in London, Antwerp, Tel Aviv and New York. The dissertation is divided into two complimentary sections. Section one focuses on the formation, emplacement, occurrence and characteristics of kimberlites and, when present, their associated trace amounts of diamonds. The section follows a logical sequence from the regional tectonic-, local structrual- and geodynamic controls on kimberlite formation and emplacement to the characteristics of individual kimberlite morphology, mineralogy, petrography and geochemistry. Finally, the environment or diamond formation, resorption and the characteristics that have led to the marketability of diamonds are discussed. Section two reviews the current exploration techniques used in locating diamondiferous kimberliies and the subsequent economic evaluation of these kimberlites. A brief history of known Southern African kimberlite occurrences, grades, tonnages, tectonic settings, ages and regional structural controls is given. The prospective countries mentioned are Angola, Botswana, Lesotho, South Africa, Swaziland, Tanzania and Zimbabwe. Exploration techniques considered are ; the application of a landscape analysis and investigation of the surface processes active in a given area, indicator mineral sampling (with reference to their mineralogy and exploration significance), remote sensing techniques (subdivided into satellite imagery and aerial photography), geophysical techniques (including the magnetic-, gravity-, electrical-, radiometric- and seismic methods as well as heat flow models), geochemical techniques, petrographic- and electron beam techniques as well as geobotanical- and geobiological techniques. Finally, a brief summary of current evaluation techniques employed on diamondiferous kimberlite deposits is presented. The review covers kimberlite sampling methods, sample processing, diamond grade distributions (with reference to the experimental variogram model, statistical methods used in grade distribution calculations as well as block definition and local grade estimation). Stone size distributions, including microdiamond counts and value estimation, are also discussed. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 1999
- Authors: Venter, Louis Johannes
- Date: 1999 , 2013-10-04
- Subjects: Kimberlite -- Africa, Southern , Diamonds -- Africa, Southern , Prospecting -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5033 , http://hdl.handle.net/10962/d1007278 , Kimberlite -- Africa, Southern , Diamonds -- Africa, Southern , Prospecting -- South Africa
- Description: The dissertation reviews the present knowledge regarding diamonds, from its formation in the lithospheric upper mantle at depths between 150 and 300 km, to its final valuation in terms of US$/carat by diamantaires in London, Antwerp, Tel Aviv and New York. The dissertation is divided into two complimentary sections. Section one focuses on the formation, emplacement, occurrence and characteristics of kimberlites and, when present, their associated trace amounts of diamonds. The section follows a logical sequence from the regional tectonic-, local structrual- and geodynamic controls on kimberlite formation and emplacement to the characteristics of individual kimberlite morphology, mineralogy, petrography and geochemistry. Finally, the environment or diamond formation, resorption and the characteristics that have led to the marketability of diamonds are discussed. Section two reviews the current exploration techniques used in locating diamondiferous kimberliies and the subsequent economic evaluation of these kimberlites. A brief history of known Southern African kimberlite occurrences, grades, tonnages, tectonic settings, ages and regional structural controls is given. The prospective countries mentioned are Angola, Botswana, Lesotho, South Africa, Swaziland, Tanzania and Zimbabwe. Exploration techniques considered are ; the application of a landscape analysis and investigation of the surface processes active in a given area, indicator mineral sampling (with reference to their mineralogy and exploration significance), remote sensing techniques (subdivided into satellite imagery and aerial photography), geophysical techniques (including the magnetic-, gravity-, electrical-, radiometric- and seismic methods as well as heat flow models), geochemical techniques, petrographic- and electron beam techniques as well as geobotanical- and geobiological techniques. Finally, a brief summary of current evaluation techniques employed on diamondiferous kimberlite deposits is presented. The review covers kimberlite sampling methods, sample processing, diamond grade distributions (with reference to the experimental variogram model, statistical methods used in grade distribution calculations as well as block definition and local grade estimation). Stone size distributions, including microdiamond counts and value estimation, are also discussed. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 1999
Genetic models for epithermal gold deposits and applications to exploration
- Authors: Veselinović, Milica
- Date: 1992
- Subjects: Gold ores -- Geology , Hydrothermal deposits
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4950 , http://hdl.handle.net/10962/d1005562 , Gold ores -- Geology , Hydrothermal deposits
- Description: Epithermal gold deposits are the product of large-scale hydrothermal systems in tectonically active regions. They form at shallow crustal levels where the physico-chemical conditions change abruptly. Two major groups of epithermal gold deposits can be distinguished based on their genetic connection with: A) Copper-molybdenum porphyry systems and B) Geothermal systems related to volcanic centres and calderas. Epithermal gold deposits connected with geothermal systems encompass three major types: adularia-sericite, acid-sulphate and disseminated replacement (the Carlin-type). Their essential ingredients are: high heat source which leads to convection of groundwater in the upper crust; source of hydrothermal fluid, metals and reduced sulphur; and high-permeability structures which allow fluid convection and metal deposition. Mixing of these ingredients leads to the formation of epithermal gold deposits throughout crustal history, without any restriction on age. The ores were deposited from near-neutral (adularia-sericite type and some of the Carlin-type) to acidic (acid-sulphate type and porphyry-related epithermal gold deposits), low-salinity, high C0₂ and high H₂S fluids, which were predominantly meteoritic in origin. The transport capability of deep fluids in epithermal hydrothermal systems may be shown to be dependent largely on their H₂S content and, through a series of fluid mineral equilibria, on temperature and on C0₂ content. The most common mechanisms of ore deposition are boiling (phase separation), mixing of fluids of different temperatures and salinities, reaction between them and wall rocks, dilution and cooling. An understanding of genetic models for epithermal gold deposits provides the basis for the selection of favourable areas for regional to prospect-scale exploration.
- Full Text:
- Date Issued: 1992
- Authors: Veselinović, Milica
- Date: 1992
- Subjects: Gold ores -- Geology , Hydrothermal deposits
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4950 , http://hdl.handle.net/10962/d1005562 , Gold ores -- Geology , Hydrothermal deposits
- Description: Epithermal gold deposits are the product of large-scale hydrothermal systems in tectonically active regions. They form at shallow crustal levels where the physico-chemical conditions change abruptly. Two major groups of epithermal gold deposits can be distinguished based on their genetic connection with: A) Copper-molybdenum porphyry systems and B) Geothermal systems related to volcanic centres and calderas. Epithermal gold deposits connected with geothermal systems encompass three major types: adularia-sericite, acid-sulphate and disseminated replacement (the Carlin-type). Their essential ingredients are: high heat source which leads to convection of groundwater in the upper crust; source of hydrothermal fluid, metals and reduced sulphur; and high-permeability structures which allow fluid convection and metal deposition. Mixing of these ingredients leads to the formation of epithermal gold deposits throughout crustal history, without any restriction on age. The ores were deposited from near-neutral (adularia-sericite type and some of the Carlin-type) to acidic (acid-sulphate type and porphyry-related epithermal gold deposits), low-salinity, high C0₂ and high H₂S fluids, which were predominantly meteoritic in origin. The transport capability of deep fluids in epithermal hydrothermal systems may be shown to be dependent largely on their H₂S content and, through a series of fluid mineral equilibria, on temperature and on C0₂ content. The most common mechanisms of ore deposition are boiling (phase separation), mixing of fluids of different temperatures and salinities, reaction between them and wall rocks, dilution and cooling. An understanding of genetic models for epithermal gold deposits provides the basis for the selection of favourable areas for regional to prospect-scale exploration.
- Full Text:
- Date Issued: 1992
The constituents of the resin of Euryops floribundus. N.E.Br.
- Authors: Woolard, Graham Robert
- Date: 1966
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4510 , http://hdl.handle.net/10962/d1013449
- Description: The aerial portions of the plant Euryops floribundus were extracted and shown to contain Euryopsonol and another sesquiterpenoid for which the name Euryopsol is proposed. An extraction of Euryops tenuissimus contained Euryopsol only. Euryopsonol, of empirical formula C₁₅ H₂₀ O₃, was previously shown to contain a hydroxyl group and a keto-group and to be doubly unsaturated. The hydroxyl group has been shown to be secondary, while the keto-group is ⋉, β, γ, δ-unsaturated, Spectroscopic and Mass spectrosmetric measurements showed euryopsonol to possess a furan ring and to be member of the eremophilane -9 of sesquiterpenoids . These proposals were confirmed by the conversion of euryopsonol to furanoeremophilone -9, thus establishing the stereochemistry at C₄, C₅ and C₁₀. This free hydroxyl group has been placed at C₃, but its stereochemistry is still unknown. Euryopsol, of empirical formula C₁₅ H₂₂ O₄, possesses an unstable furan ring and readily undergoes autoxidation, probably to a more stable ¥-lactone. It contains two vicinal hydroxyl groups, one of which was placed by Mass spectrometry at C₉. If euryopsol possesses the eremophilane skeleton the other hydroxyl group must be at C₁₀.
- Full Text:
- Date Issued: 1966
- Authors: Woolard, Graham Robert
- Date: 1966
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4510 , http://hdl.handle.net/10962/d1013449
- Description: The aerial portions of the plant Euryops floribundus were extracted and shown to contain Euryopsonol and another sesquiterpenoid for which the name Euryopsol is proposed. An extraction of Euryops tenuissimus contained Euryopsol only. Euryopsonol, of empirical formula C₁₅ H₂₀ O₃, was previously shown to contain a hydroxyl group and a keto-group and to be doubly unsaturated. The hydroxyl group has been shown to be secondary, while the keto-group is ⋉, β, γ, δ-unsaturated, Spectroscopic and Mass spectrosmetric measurements showed euryopsonol to possess a furan ring and to be member of the eremophilane -9 of sesquiterpenoids . These proposals were confirmed by the conversion of euryopsonol to furanoeremophilone -9, thus establishing the stereochemistry at C₄, C₅ and C₁₀. This free hydroxyl group has been placed at C₃, but its stereochemistry is still unknown. Euryopsol, of empirical formula C₁₅ H₂₂ O₄, possesses an unstable furan ring and readily undergoes autoxidation, probably to a more stable ¥-lactone. It contains two vicinal hydroxyl groups, one of which was placed by Mass spectrometry at C₉. If euryopsol possesses the eremophilane skeleton the other hydroxyl group must be at C₁₀.
- Full Text:
- Date Issued: 1966
- «
- ‹
- 1
- ›
- »