1H NMR-based kinetic and theoretical studies of the simultaneous formation of two discrete rotameric systems of a novel difenchyl sulfite ester
- Singh, Alicia, Kaye, Perry T, Lobb, Kevin A
- Authors: Singh, Alicia , Kaye, Perry T , Lobb, Kevin A
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447925 , vital:74684 , xlink:href="https://doi.org/10.1016/j.tet.2017.10.059"
- Description: Attempted repetition of a reported synthesis of fenchene from fenchol has afforded, in high overall yield, a mixture shown by spectroscopic and elemental analysis to comprise a pair of discrete rotameric systems of a novel 2-endo-2′-endo-difenchyl sulfite ester. The kinetics of the formation of these dimeric rotameric systems (I and II) has been explored experimentally, using 1H NMR spectroscopic analysis, and theoretically at molecular and quantum mechanical levels. Construction of a theoretical model has permitted calculation of rate constants for each of the steps, while modelling of the transition state complexes corresponding to the rate-determining steps for the formation of the rotameric systems I and II has revealed their independent access to further sets of interconverting rotamers.
- Full Text:
- Date Issued: 2017
- Authors: Singh, Alicia , Kaye, Perry T , Lobb, Kevin A
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447925 , vital:74684 , xlink:href="https://doi.org/10.1016/j.tet.2017.10.059"
- Description: Attempted repetition of a reported synthesis of fenchene from fenchol has afforded, in high overall yield, a mixture shown by spectroscopic and elemental analysis to comprise a pair of discrete rotameric systems of a novel 2-endo-2′-endo-difenchyl sulfite ester. The kinetics of the formation of these dimeric rotameric systems (I and II) has been explored experimentally, using 1H NMR spectroscopic analysis, and theoretically at molecular and quantum mechanical levels. Construction of a theoretical model has permitted calculation of rate constants for each of the steps, while modelling of the transition state complexes corresponding to the rate-determining steps for the formation of the rotameric systems I and II has revealed their independent access to further sets of interconverting rotamers.
- Full Text:
- Date Issued: 2017
1H NMR-based kinetic-mechanistic study of the intramolecular trans-esterification of 2-exo-3-exo-dihydroxybornane monoacrylate esters
- Duggan, Andrew R, Mciteka, Lulama P, Lobb, Kevin A, Kaye, Perry T
- Authors: Duggan, Andrew R , Mciteka, Lulama P , Lobb, Kevin A , Kaye, Perry T
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448871 , vital:74767 , xlink:href="https://hdl.handle.net/10520/EJC135616"
- Description: A 1H NMR study of the acid-catalyzed, intramolecular trans-esterification between isomeric 2-exo-3-exo-dihydroxybornane monoacrylate esters has afforded insights into the reaction mechanism and permitted the determination of kinetic and thermodynamic parameters for the pseudo-first-order processes.
- Full Text:
- Date Issued: 2013
- Authors: Duggan, Andrew R , Mciteka, Lulama P , Lobb, Kevin A , Kaye, Perry T
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448871 , vital:74767 , xlink:href="https://hdl.handle.net/10520/EJC135616"
- Description: A 1H NMR study of the acid-catalyzed, intramolecular trans-esterification between isomeric 2-exo-3-exo-dihydroxybornane monoacrylate esters has afforded insights into the reaction mechanism and permitted the determination of kinetic and thermodynamic parameters for the pseudo-first-order processes.
- Full Text:
- Date Issued: 2013
20 Years of changes in media ownership: journalism now
- Authors: Rumney, Reg
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454192 , vital:75324 , https://hdl.handle.net/10520/EJC175778
- Description: In reviewing the transformation of the news media in South Africa over the last 20 years, you might be tempted to think that nothing has changed.
- Full Text:
- Date Issued: 2015
- Authors: Rumney, Reg
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454192 , vital:75324 , https://hdl.handle.net/10520/EJC175778
- Description: In reviewing the transformation of the news media in South Africa over the last 20 years, you might be tempted to think that nothing has changed.
- Full Text:
- Date Issued: 2015
2010 FIFA World Cup stadium investment: Does the post-event usage justify the expenditure?
- Humphrey, Luke, Fraser, Gavin C G
- Authors: Humphrey, Luke , Fraser, Gavin C G
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/470954 , vital:77403 , https://www.ajol.info/index.php/aref/article/view/162154
- Description: This paper provides an ex-post analysis of the utilisation of the stadiums that were built for the 2010 FIFA World Cup. The South African government invested approximately US $1.57 billion and US $523 million into the development of new stadiums and upgrades to existing stadiums, respectively. This paper determines whether the substantial investments into the stadiums’ infrastructure are justified by the utilisation of the stadiums after the 2010 FIFA World Cup event. A utilisation rate and a stadium usage index were used to analyse the utilisation benefits derived from the stadiums. Generally, the results suggest that there has been a significant decline in the utilisation of stadiums following the 2010 FIFA World Cup. Furthermore, the results indicate that the exorbitant costs of the stadiums for the 2010 FIFA World Cup were significant in relation to the underutilisation of the stadiums in the wake of the event. The 2010 FIFA World Cup has left the country with an expenditure legacy of an oversupply of stadiums, thus making some of the stadiums unsustainable. The results of this study appear to be in line with existing empirical research, which suggests that stadiums tend be underutilised and pose a financial burden for a host nation, subsequent to a mega-event.
- Full Text:
- Date Issued: 2016
- Authors: Humphrey, Luke , Fraser, Gavin C G
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/470954 , vital:77403 , https://www.ajol.info/index.php/aref/article/view/162154
- Description: This paper provides an ex-post analysis of the utilisation of the stadiums that were built for the 2010 FIFA World Cup. The South African government invested approximately US $1.57 billion and US $523 million into the development of new stadiums and upgrades to existing stadiums, respectively. This paper determines whether the substantial investments into the stadiums’ infrastructure are justified by the utilisation of the stadiums after the 2010 FIFA World Cup event. A utilisation rate and a stadium usage index were used to analyse the utilisation benefits derived from the stadiums. Generally, the results suggest that there has been a significant decline in the utilisation of stadiums following the 2010 FIFA World Cup. Furthermore, the results indicate that the exorbitant costs of the stadiums for the 2010 FIFA World Cup were significant in relation to the underutilisation of the stadiums in the wake of the event. The 2010 FIFA World Cup has left the country with an expenditure legacy of an oversupply of stadiums, thus making some of the stadiums unsustainable. The results of this study appear to be in line with existing empirical research, which suggests that stadiums tend be underutilised and pose a financial burden for a host nation, subsequent to a mega-event.
- Full Text:
- Date Issued: 2016
2OS
- Authors: Machanick, Philip
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439214 , vital:73556 , https://homes.cs.ru.ac.za/philip/Courses/CS2-OS/Cs2ToOS.pdf
- Description: In this book I approach the problem of understanding an OS from the point of view of a C programmer who needs to understand enough of how an OS works to program efficiently and avoid traps and pitfalls arising from not understanding what is happening underneath you. If you have a deep understanding of the memory system, you will not program in a style that loses significant performance by breaking the assumptions of the OS designer. If you have an understanding of how IO works, you can make good use of OS services. As you work through this book you will see other examples.
- Full Text:
- Date Issued: 2016
- Authors: Machanick, Philip
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439214 , vital:73556 , https://homes.cs.ru.ac.za/philip/Courses/CS2-OS/Cs2ToOS.pdf
- Description: In this book I approach the problem of understanding an OS from the point of view of a C programmer who needs to understand enough of how an OS works to program efficiently and avoid traps and pitfalls arising from not understanding what is happening underneath you. If you have a deep understanding of the memory system, you will not program in a style that loses significant performance by breaking the assumptions of the OS designer. If you have an understanding of how IO works, you can make good use of OS services. As you work through this book you will see other examples.
- Full Text:
- Date Issued: 2016
31P NMR kinetic study of the tandem cleavage of phosphonate esters by bromotrimethylsilane
- Conibear, Anne C, Lobb, Kevin A, Kaye, Perry T
- Authors: Conibear, Anne C , Lobb, Kevin A , Kaye, Perry T
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449304 , vital:74810 , xlink:href="https://doi.org/10.1016/j.tet.2010.08.058"
- Description: 1H and 31P NMR methods have been used to access rate constants and activation parameters for each of the consecutive second-order silylation reactions involved in the overall transformation (1a→3a→4a), while computational optimisation of the rate constants obtained from the initial, linear phase of each reaction has permitted an excellent fit with the experimental data for the entire course of the reaction.
- Full Text:
- Date Issued: 2010
- Authors: Conibear, Anne C , Lobb, Kevin A , Kaye, Perry T
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449304 , vital:74810 , xlink:href="https://doi.org/10.1016/j.tet.2010.08.058"
- Description: 1H and 31P NMR methods have been used to access rate constants and activation parameters for each of the consecutive second-order silylation reactions involved in the overall transformation (1a→3a→4a), while computational optimisation of the rate constants obtained from the initial, linear phase of each reaction has permitted an excellent fit with the experimental data for the entire course of the reaction.
- Full Text:
- Date Issued: 2010
31° South: the physiology of adaptation to arid conditions in a passerine bird.
- Ribeiro, Ângela M, Puetz, Lara, Pattinson, Nicholas B, Dalén, Love, Deng, Yuan, Zhang, Guojie, da Fonseca, Rute R, Smit, Ben, Gilbert, M. Thomas P
- Authors: Ribeiro, Ângela M , Puetz, Lara , Pattinson, Nicholas B , Dalén, Love , Deng, Yuan , Zhang, Guojie , da Fonseca, Rute R , Smit, Ben , Gilbert, M. Thomas P
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441508 , vital:73894 , https://doi.org/10.1111/mec.15176
- Description: Arid environments provide ideal ground for investigating the mechanisms of adaptive evolution. High temperatures and low water availability are relentless stressors for many endotherms, including birds; yet birds persist in deserts. While physiological adaptation probably involves metabolic phenotypes, the underlying mechanisms (plasticity, genetics) are largely uncharacterized. To explore this, we took an intraspecific approach that focused on a species that is resident over a mesic to arid gradient, the Karoo scrub‐robin (Cercotrichas coryphaeus). Specifically, we integrated environmental (climatic and primary productivity), physiological (metabolic rates: a measure of energy expenditure), genotypic (genetic variation underlying the machinery of energy production) and microbiome (involved in processing food from where energy is retrieved) data, to infer the mechanism of physiological adaptation. We that found the variation in energetic physiology phenotypes and gut microbiome composition are associated with environmental features as well as with variation in genes underlying energy metabolic pathways. Specifically, we identified a small list of candidate adaptive genes, some of them with known ties to relevant physiology phenotypes. Together our results suggest that selective pressures on energetic physiology mediated by genes related to energy homeostasis and possibly microbiota composition may facilitate adaptation to local conditions and provide an explanation to the high avian intraspecific divergence observed in harsh environments.
- Full Text:
- Date Issued: 2019
- Authors: Ribeiro, Ângela M , Puetz, Lara , Pattinson, Nicholas B , Dalén, Love , Deng, Yuan , Zhang, Guojie , da Fonseca, Rute R , Smit, Ben , Gilbert, M. Thomas P
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441508 , vital:73894 , https://doi.org/10.1111/mec.15176
- Description: Arid environments provide ideal ground for investigating the mechanisms of adaptive evolution. High temperatures and low water availability are relentless stressors for many endotherms, including birds; yet birds persist in deserts. While physiological adaptation probably involves metabolic phenotypes, the underlying mechanisms (plasticity, genetics) are largely uncharacterized. To explore this, we took an intraspecific approach that focused on a species that is resident over a mesic to arid gradient, the Karoo scrub‐robin (Cercotrichas coryphaeus). Specifically, we integrated environmental (climatic and primary productivity), physiological (metabolic rates: a measure of energy expenditure), genotypic (genetic variation underlying the machinery of energy production) and microbiome (involved in processing food from where energy is retrieved) data, to infer the mechanism of physiological adaptation. We that found the variation in energetic physiology phenotypes and gut microbiome composition are associated with environmental features as well as with variation in genes underlying energy metabolic pathways. Specifically, we identified a small list of candidate adaptive genes, some of them with known ties to relevant physiology phenotypes. Together our results suggest that selective pressures on energetic physiology mediated by genes related to energy homeostasis and possibly microbiota composition may facilitate adaptation to local conditions and provide an explanation to the high avian intraspecific divergence observed in harsh environments.
- Full Text:
- Date Issued: 2019
4-Azidoaniline-based electropolymer as a building block for functionalisation of conductive surfaces
- Coates, Megan, Elamari, Hichem, Girard, Christian, Griveau, Sophie, Nyokong, Tebello, Bedioui, Fethi
- Authors: Coates, Megan , Elamari, Hichem , Girard, Christian , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244404 , vital:51254 , xlink:href="https://doi.org/10.1016/j.jelechem.2012.01.001"
- Description: We propose in this work to compare three approaches using 4-azidoaniline combined with “click” chemistry and electrochemistry to anchor ferrocene moieties at glassy carbon surfaces. The immobilisation of a newly synthesised molecule, 4-(4-ferrocenyl-1H-1,2,3-triazol-1-yl)aniline, through direct electropolymerisation or via in situ diazotization followed by electrografting is studied by analysing the samples by XPS and electrochemistry.
- Full Text:
- Date Issued: 2012
4-Azidoaniline-based electropolymer as a building block for functionalisation of conductive surfaces
- Authors: Coates, Megan , Elamari, Hichem , Girard, Christian , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244404 , vital:51254 , xlink:href="https://doi.org/10.1016/j.jelechem.2012.01.001"
- Description: We propose in this work to compare three approaches using 4-azidoaniline combined with “click” chemistry and electrochemistry to anchor ferrocene moieties at glassy carbon surfaces. The immobilisation of a newly synthesised molecule, 4-(4-ferrocenyl-1H-1,2,3-triazol-1-yl)aniline, through direct electropolymerisation or via in situ diazotization followed by electrografting is studied by analysing the samples by XPS and electrochemistry.
- Full Text:
- Date Issued: 2012
4-Bis (4-aminophenoxy) phenoxy derivitized phthalocyanine conjugated to metallic nanoparticles
- Nwaji, Njemuwa, Mack, John, Nyokong, Tebello
- Authors: Nwaji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188965 , vital:44802 , xlink:href="https://doi.org/10.1039/C7NJ02718D"
- Description: In this study, the photophysical, nonlinear absorption and nonlinear optical limiting properties of 4-(2,4-bis(4-aminophenoxy)phenoxy) phthalocyinato zinc(II) phthalocyanine (6) conjugated to metallic nanoparticles have been investigated using open aperture Z-scan techniques using 532 nm nanosecond pulses. The nonlinear optical response demonstrated that the studied complex and the nanoconjugates exhibit higher excited state absorption cross-section compared to ground state absorption. Enhanced optical limiting performance was observed when complex 6 was conjugated to nanoparticles with 6CB-AuNPs (CB = covalent bond) showing the highest optical limiting threshold of 0.36 J cm−2.
- Full Text:
- Date Issued: 2017
- Authors: Nwaji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188965 , vital:44802 , xlink:href="https://doi.org/10.1039/C7NJ02718D"
- Description: In this study, the photophysical, nonlinear absorption and nonlinear optical limiting properties of 4-(2,4-bis(4-aminophenoxy)phenoxy) phthalocyinato zinc(II) phthalocyanine (6) conjugated to metallic nanoparticles have been investigated using open aperture Z-scan techniques using 532 nm nanosecond pulses. The nonlinear optical response demonstrated that the studied complex and the nanoconjugates exhibit higher excited state absorption cross-section compared to ground state absorption. Enhanced optical limiting performance was observed when complex 6 was conjugated to nanoparticles with 6CB-AuNPs (CB = covalent bond) showing the highest optical limiting threshold of 0.36 J cm−2.
- Full Text:
- Date Issued: 2017
5-Fu inclusion complex capped gold nanoparticles for breast cancer therapy
- Lakkakula, Jaya R, Krause, Rui W M, Divakaran, Deepika, Barage, Sagar, Srivastava, Rohit
- Authors: Lakkakula, Jaya R , Krause, Rui W M , Divakaran, Deepika , Barage, Sagar , Srivastava, Rohit
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191713 , vital:45150 , xlink:href="https://doi.org/10.1016/j.molliq.2021.117262"
- Description: We have attempted to prolong the circulation time and increase the solubility of 5-Fluorouracil by complexing it with cyclodextrin and then further conjugating onto the gold nanoparticle to form 5Fu ICAu. The 1H NMR and molecular docking studies suggested that 5-Fu was included within the 2HP-β-CD cavity and H-5 proton probably serves as the binding site for stabilization of the inclusion complex. The 5Fu-ICAu showed higher cell inhibition rate when studied on MDA-MB-231 and MCF-7 breast cancer cell lines due to the enhanced permeability and retention (EPR) effect by allowing the selective accumulation of nanoparticles at tumor site. This unique system can serve as a novel nanocarrier for delivery of hydrophobic drugs.
- Full Text:
- Date Issued: 2021
- Authors: Lakkakula, Jaya R , Krause, Rui W M , Divakaran, Deepika , Barage, Sagar , Srivastava, Rohit
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191713 , vital:45150 , xlink:href="https://doi.org/10.1016/j.molliq.2021.117262"
- Description: We have attempted to prolong the circulation time and increase the solubility of 5-Fluorouracil by complexing it with cyclodextrin and then further conjugating onto the gold nanoparticle to form 5Fu ICAu. The 1H NMR and molecular docking studies suggested that 5-Fu was included within the 2HP-β-CD cavity and H-5 proton probably serves as the binding site for stabilization of the inclusion complex. The 5Fu-ICAu showed higher cell inhibition rate when studied on MDA-MB-231 and MCF-7 breast cancer cell lines due to the enhanced permeability and retention (EPR) effect by allowing the selective accumulation of nanoparticles at tumor site. This unique system can serve as a novel nanocarrier for delivery of hydrophobic drugs.
- Full Text:
- Date Issued: 2021
A 3, 5-DistyrylBODIPY Dye Functionalized with Boronic Acid Groups for Direct Electrochemical Glucose Sensing
- Ndebele, Nobuhle, Mack, John, Nyokong, Tebello
- Authors: Ndebele, Nobuhle , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187556 , vital:44671 , xlink:href="https://doi.org/10.1002/elan.201800651"
- Description: The synthesis and characterization of a novel BODIPY dye functionalized with bis-boronic acid groups to enable direct glucose sensing through selective recognition of carbohydrates is reported. Styrylation with boronic acid groups at the 3,5-positions of the BODIPY core results in an extension of the π-conjugation system of the dye and in a red-shift of the main absorption band from 500 to 637 nm. The functionalized BODIPY dye was adsorbed on a glassy carbon electrode using the drop and dry method. Modified and bare electrodes were characterized using cyclic voltammetry and scanning electrochemical microscopy, while glucose detection was carried out by using differential pulse voltammetry and chronoamperometry. The detection limit was determined to be 1.42 μM. The dye was found to be selective and sensitive towards glucose, since likely interferences have only minor effects on the glucose detection.
- Full Text:
- Date Issued: 2019
- Authors: Ndebele, Nobuhle , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187556 , vital:44671 , xlink:href="https://doi.org/10.1002/elan.201800651"
- Description: The synthesis and characterization of a novel BODIPY dye functionalized with bis-boronic acid groups to enable direct glucose sensing through selective recognition of carbohydrates is reported. Styrylation with boronic acid groups at the 3,5-positions of the BODIPY core results in an extension of the π-conjugation system of the dye and in a red-shift of the main absorption band from 500 to 637 nm. The functionalized BODIPY dye was adsorbed on a glassy carbon electrode using the drop and dry method. Modified and bare electrodes were characterized using cyclic voltammetry and scanning electrochemical microscopy, while glucose detection was carried out by using differential pulse voltammetry and chronoamperometry. The detection limit was determined to be 1.42 μM. The dye was found to be selective and sensitive towards glucose, since likely interferences have only minor effects on the glucose detection.
- Full Text:
- Date Issued: 2019
A baseline study of potentially malicious activity across five network telescopes
- Authors: Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429714 , vital:72634 , https://ieeexplore.ieee.org/abstract/document/6568378
- Description: +This paper explores the Internet Background Radiation (IBR) observed across five distinct network telescopes over a 15 month period. These network telescopes consisting of a /24 netblock each and are deployed in IP space administered by TENET, the tertiary education network in South Africa covering three numerically distant /8 network blocks. The differences and similarities in the observed network traffic are explored. Two anecdotal case studies are presented relating to the MS08-067 and MS12-020 vulnerabilities in the Microsoft Windows platforms. The first of these is related to the Conficker worm outbreak in 2008, and traffic targeting 445/tcp remains one of the top constituents of IBR as observed on the telescopes. The case of MS12-020 is of interest, as a long period of scanning activity targeting 3389/tcp, used by the Microsoft RDP service, was observed, with a significant drop on activity relating to the release of the security advisory and patch. Other areas of interest are highlighted, particularly where correlation in scanning activity was observed across the sensors. The paper concludes with some discussion on the application of network telescopes as part of a cyber-defence solution.
- Full Text:
- Date Issued: 2013
- Authors: Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429714 , vital:72634 , https://ieeexplore.ieee.org/abstract/document/6568378
- Description: +This paper explores the Internet Background Radiation (IBR) observed across five distinct network telescopes over a 15 month period. These network telescopes consisting of a /24 netblock each and are deployed in IP space administered by TENET, the tertiary education network in South Africa covering three numerically distant /8 network blocks. The differences and similarities in the observed network traffic are explored. Two anecdotal case studies are presented relating to the MS08-067 and MS12-020 vulnerabilities in the Microsoft Windows platforms. The first of these is related to the Conficker worm outbreak in 2008, and traffic targeting 445/tcp remains one of the top constituents of IBR as observed on the telescopes. The case of MS12-020 is of interest, as a long period of scanning activity targeting 3389/tcp, used by the Microsoft RDP service, was observed, with a significant drop on activity relating to the release of the security advisory and patch. Other areas of interest are highlighted, particularly where correlation in scanning activity was observed across the sensors. The paper concludes with some discussion on the application of network telescopes as part of a cyber-defence solution.
- Full Text:
- Date Issued: 2013
A Bernsteinian analysis of the integration of natural resource management in the curriculum of a rural disadvantaged school
- Authors: Nsubuga, Yvonne
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386415 , vital:68139 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122771"
- Description: Knowledge integration is one of the key principles that underpin curriculum reform in post-apartheid South Africa. One form of teacher support that has been adopted in South Africa is to provide schools throughout the country with samples of pedagogic texts such as curriculum documents and examination exemplars to act as guidelines to teachers as they implement this new curriculum requirement. In the isolated and under-resourced rural schools of South Africa, these texts are the main form of curriculum guidance to teachers. Hence the knowledge integration principles and messages conveyed within these texts are of crucial importance. One contributory factor to the lack of information on knowledge integration at rural underresourced schools is the lack of simple and effective research tools by which to analyse and compare the extent of knowledge integration within pedagogic texts and classroom practices. This article reports on a Bernstein informed analysis that was carried out on three different Grade 10 Life Sciences pedagogic texts in order to assess the extent to which they integrate natural resource management (NRM). The study involved the construction of two indicator frameworks as the research tools with which the analysis was conducted. Results from the analysis showed that although the official Grade 10 Life Sciences pedagogic texts contained very high levels of NRM integration, this was not the case for the Grade 10 Life Sciences text that was produced at the school level. The study provides useful insight into curriculum recontextualisation at a rural under-resourced school through the lens of NRM integration within the Grade 10 Life Sciences pedagogic texts. Such insight has the potential to contribute to better curriculum design and implementation strategies to service schools. This will hopefully help to narrow the gap that currently exists between the official and enacted curricula.
- Full Text:
- Date Issued: 2008
- Authors: Nsubuga, Yvonne
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386415 , vital:68139 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122771"
- Description: Knowledge integration is one of the key principles that underpin curriculum reform in post-apartheid South Africa. One form of teacher support that has been adopted in South Africa is to provide schools throughout the country with samples of pedagogic texts such as curriculum documents and examination exemplars to act as guidelines to teachers as they implement this new curriculum requirement. In the isolated and under-resourced rural schools of South Africa, these texts are the main form of curriculum guidance to teachers. Hence the knowledge integration principles and messages conveyed within these texts are of crucial importance. One contributory factor to the lack of information on knowledge integration at rural underresourced schools is the lack of simple and effective research tools by which to analyse and compare the extent of knowledge integration within pedagogic texts and classroom practices. This article reports on a Bernstein informed analysis that was carried out on three different Grade 10 Life Sciences pedagogic texts in order to assess the extent to which they integrate natural resource management (NRM). The study involved the construction of two indicator frameworks as the research tools with which the analysis was conducted. Results from the analysis showed that although the official Grade 10 Life Sciences pedagogic texts contained very high levels of NRM integration, this was not the case for the Grade 10 Life Sciences text that was produced at the school level. The study provides useful insight into curriculum recontextualisation at a rural under-resourced school through the lens of NRM integration within the Grade 10 Life Sciences pedagogic texts. Such insight has the potential to contribute to better curriculum design and implementation strategies to service schools. This will hopefully help to narrow the gap that currently exists between the official and enacted curricula.
- Full Text:
- Date Issued: 2008
A Canonical Implementation Of The Advanced Encryption Standard On The Graphics Processing Unit
- Pilkington, Nick, Irwin, Barry V W
- Authors: Pilkington, Nick , Irwin, Barry V W
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430007 , vital:72659 , https://digifors.cs.up.ac.za/issa/2008/Proceedings/Research/47.pdf
- Description: This paper will present an implementation of the Advanced Encryption Standard (AES) on the graphics processing unit (GPU). It investigates the ease of implementation from first principles and the difficulties encountered. It also presents a performance analysis to evaluate if the GPU is a viable option for a cryptographics platform. The AES implementation is found to yield orders of maginitude increased performance when compared to CPU based implementations. Although the implementation introduces complica-tions, these are quickly becoming mitigated by the growing accessibility pro-vided by general programming on graphics processing units (GPGPU) frameworks like NVIDIA’s Compute Uniform Device Architechture (CUDA) and AMD/ATI’s Close to Metal (CTM).
- Full Text:
- Date Issued: 2008
- Authors: Pilkington, Nick , Irwin, Barry V W
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430007 , vital:72659 , https://digifors.cs.up.ac.za/issa/2008/Proceedings/Research/47.pdf
- Description: This paper will present an implementation of the Advanced Encryption Standard (AES) on the graphics processing unit (GPU). It investigates the ease of implementation from first principles and the difficulties encountered. It also presents a performance analysis to evaluate if the GPU is a viable option for a cryptographics platform. The AES implementation is found to yield orders of maginitude increased performance when compared to CPU based implementations. Although the implementation introduces complica-tions, these are quickly becoming mitigated by the growing accessibility pro-vided by general programming on graphics processing units (GPGPU) frameworks like NVIDIA’s Compute Uniform Device Architechture (CUDA) and AMD/ATI’s Close to Metal (CTM).
- Full Text:
- Date Issued: 2008
A capability approach: Its potential for transformative education research focusing on education for sustainable development and gender issues in science teacher education
- Authors: Chikunda, Charles
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387120 , vital:68208 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122266"
- Description: In this article, I use the capability approach to explore the role that the science, mathematics and technical subjects (SMTs) teacher education curriculum can play as a ‘gender conversion factor’. This comes amidst evidence that a major hindrance to the participation of girls in these disciplines is a lack of gender responsiveness in the pedagogy applied in schools. Seven teacher educators, who were purposively sampled at a Technical Teachers’ College in Zimbabwe, were the research participants. I adopted a case study design in which I used in-depth interviews, focus-group discussions and document analysis to generate data. Data was analysed deductively using predetermined themes based on an analytical tool anchored on Sen’s two, but quite distinct, aspects of freedom, that is, the opportunity aspect and the process aspect of freedom. The findings reveal that there is a limited awareness of gender issues among teacher educators, and that these issues are not being transformed into curriculum practice. All in all, it is evident that curriculum practices of SMTs teacher educators are riddled with gender blindness and so trainee teachers graduate from college without the necessary agency to deal with personal, social and environmental conversion factors that can play a role in girls converting the curriculum into functionings (beings and doings) and wider freedoms and valued beings and doings (capabilities).
- Full Text:
- Date Issued: 2013
- Authors: Chikunda, Charles
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387120 , vital:68208 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122266"
- Description: In this article, I use the capability approach to explore the role that the science, mathematics and technical subjects (SMTs) teacher education curriculum can play as a ‘gender conversion factor’. This comes amidst evidence that a major hindrance to the participation of girls in these disciplines is a lack of gender responsiveness in the pedagogy applied in schools. Seven teacher educators, who were purposively sampled at a Technical Teachers’ College in Zimbabwe, were the research participants. I adopted a case study design in which I used in-depth interviews, focus-group discussions and document analysis to generate data. Data was analysed deductively using predetermined themes based on an analytical tool anchored on Sen’s two, but quite distinct, aspects of freedom, that is, the opportunity aspect and the process aspect of freedom. The findings reveal that there is a limited awareness of gender issues among teacher educators, and that these issues are not being transformed into curriculum practice. All in all, it is evident that curriculum practices of SMTs teacher educators are riddled with gender blindness and so trainee teachers graduate from college without the necessary agency to deal with personal, social and environmental conversion factors that can play a role in girls converting the curriculum into functionings (beings and doings) and wider freedoms and valued beings and doings (capabilities).
- Full Text:
- Date Issued: 2013
A career in photophysicochemical and electrochemical properties of phthalocyanine: A Linstead Career Award paper
- Authors: Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186045 , vital:44458 , xlink:href="https://doi.org/10.1142/S1088424620300037"
- Description: This manuscript highlights the author’s contributions to phthalocyanine chemistry, especially the applications based on their electrochemistry and photophysicochemistry. In particular, the use of phthalocyanines as electrocatalysts and photocatalysts is presented. For photocatalysis, photodynamic antimicrobial chemotherapy and pollution control using green technologies are highlighted. For electrocatalysis the phthalocyanines are employed for the detection of pollutants and environmentally important molecules. Phthalocyanines are combined with nanomaterials for improved photocatalysis and electrocatalysis.
- Full Text:
- Date Issued: 2020
- Authors: Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186045 , vital:44458 , xlink:href="https://doi.org/10.1142/S1088424620300037"
- Description: This manuscript highlights the author’s contributions to phthalocyanine chemistry, especially the applications based on their electrochemistry and photophysicochemistry. In particular, the use of phthalocyanines as electrocatalysts and photocatalysts is presented. For photocatalysis, photodynamic antimicrobial chemotherapy and pollution control using green technologies are highlighted. For electrocatalysis the phthalocyanines are employed for the detection of pollutants and environmentally important molecules. Phthalocyanines are combined with nanomaterials for improved photocatalysis and electrocatalysis.
- Full Text:
- Date Issued: 2020
A Century of South African Theatre
- Authors: Krueger, Anton
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229623 , vital:49694 , xlink:href="https://doi.org/10.1080/10137548.2020.1716515"
- Description: In many ways, this is an updated repackaging of Loren Kruger's seminal work of 20 years ago, Plays, Pageants and the Drama of South Africa (1999). The material has been extensively revised and reworked using similar categories as the first book, including: pageantry and representations of nationhood, neo-colonial theatre, urbanization and its consequences; the rise of Afrikaans theatre; theatres of resistance; black consciousness; and contemporary theatre. Some of these sections have been extended (such as a longer discussion of HIE Dhlomo) and there is also a completely new section which has not been published elsewhere on current theatre trends (cleverly titled “The Constitution of South African Theatre at the Present Time”).
- Full Text:
- Date Issued: 2019
- Authors: Krueger, Anton
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229623 , vital:49694 , xlink:href="https://doi.org/10.1080/10137548.2020.1716515"
- Description: In many ways, this is an updated repackaging of Loren Kruger's seminal work of 20 years ago, Plays, Pageants and the Drama of South Africa (1999). The material has been extensively revised and reworked using similar categories as the first book, including: pageantry and representations of nationhood, neo-colonial theatre, urbanization and its consequences; the rise of Afrikaans theatre; theatres of resistance; black consciousness; and contemporary theatre. Some of these sections have been extended (such as a longer discussion of HIE Dhlomo) and there is also a completely new section which has not been published elsewhere on current theatre trends (cleverly titled “The Constitution of South African Theatre at the Present Time”).
- Full Text:
- Date Issued: 2019
A Change Project story: learning and caring for South Africa’s rivers
- Authors: Chetty, Preven
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391060 , vital:68613 , xlink:href="https://eeasa.org.za/wp-content/uploads/2023/02/Final-EEASA-Bulletin-20212022-Final.pdf"
- Description: Water quality and scarcity is a major concern in Southern Africa and globally especially as the threat of climate change looms even closer. The current drought in South Africa and worsening rainfall has exposed the brittle nature of this country’s resilience to water shortages. Compounded to this is the fact that most rivers in South Africa are not adequately cared for and are under tremendous strain. Everyone who depends on these rivers whether directly or indirectly will soon be entering a new era where water will no longer be a ubiquitous commodity.
- Full Text:
- Date Issued: 2022
- Authors: Chetty, Preven
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391060 , vital:68613 , xlink:href="https://eeasa.org.za/wp-content/uploads/2023/02/Final-EEASA-Bulletin-20212022-Final.pdf"
- Description: Water quality and scarcity is a major concern in Southern Africa and globally especially as the threat of climate change looms even closer. The current drought in South Africa and worsening rainfall has exposed the brittle nature of this country’s resilience to water shortages. Compounded to this is the fact that most rivers in South Africa are not adequately cared for and are under tremendous strain. Everyone who depends on these rivers whether directly or indirectly will soon be entering a new era where water will no longer be a ubiquitous commodity.
- Full Text:
- Date Issued: 2022
A checklist of South African theses and dissertations on Shakespeare
- Authors: Wright, Laurence
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/455547 , vital:75438 , https://hdl.handle.net/10520/AJA1011582X_23
- Description: This checklist is in two parts. The first lists South African Shakespearean theses and dissertations, as well as some work on Shakespeare completed abroad by South Africans recently or currently active in the country. A few items in which Shakespeare is an important subordinate focus are included. The second list is devoted to Shakespearean pedagogy. Neither list is comprehensive.
- Full Text:
- Date Issued: 1993
- Authors: Wright, Laurence
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/455547 , vital:75438 , https://hdl.handle.net/10520/AJA1011582X_23
- Description: This checklist is in two parts. The first lists South African Shakespearean theses and dissertations, as well as some work on Shakespeare completed abroad by South Africans recently or currently active in the country. A few items in which Shakespeare is an important subordinate focus are included. The second list is devoted to Shakespearean pedagogy. Neither list is comprehensive.
- Full Text:
- Date Issued: 1993
A chiral hemiporphyrazine derivative
- Wu, Yanping, Gai, Lizhi, Xiao, Xuqiong, Lu, Hua, Li, Zhifang, Mack, John, Harris, Jessica, Nyokong, Tebello, Shen, Zhen
- Authors: Wu, Yanping , Gai, Lizhi , Xiao, Xuqiong , Lu, Hua , Li, Zhifang , Mack, John , Harris, Jessica , Nyokong, Tebello , Shen, Zhen
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240404 , vital:50831 , xlink:href="https://doi.org/10.1002/asia.201600754"
- Description: The synthesis of an optically active hemiporphyrazine with chiral binaphthyl substituents (1) is reported, providing the first example of the incorporation of an intrinsically chiral moiety into the macrocyclic core of a hemiporphyrazine analogue. A negative circular dichroism (CD) signal is observed in the 325–450 nm region of the CD spectrum of (S,S)-1, while mainly positive bands are observed in the 220–325 nm region. Mirror symmetry is observed across the entire wavelength range of the CD spectra of (R,R)-1 and (S,S)-1. An irreversible one-electron oxidation wave with an onset potential at 1.07 V is observed by cyclic voltammetry, along with a reversible one-electron reduction wave at −0.85 V. Density functional calculations reproduce the experimentally observed data and trends, and provide further insight into the nature of the electronic transitions.
- Full Text:
- Date Issued: 2016
- Authors: Wu, Yanping , Gai, Lizhi , Xiao, Xuqiong , Lu, Hua , Li, Zhifang , Mack, John , Harris, Jessica , Nyokong, Tebello , Shen, Zhen
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240404 , vital:50831 , xlink:href="https://doi.org/10.1002/asia.201600754"
- Description: The synthesis of an optically active hemiporphyrazine with chiral binaphthyl substituents (1) is reported, providing the first example of the incorporation of an intrinsically chiral moiety into the macrocyclic core of a hemiporphyrazine analogue. A negative circular dichroism (CD) signal is observed in the 325–450 nm region of the CD spectrum of (S,S)-1, while mainly positive bands are observed in the 220–325 nm region. Mirror symmetry is observed across the entire wavelength range of the CD spectra of (R,R)-1 and (S,S)-1. An irreversible one-electron oxidation wave with an onset potential at 1.07 V is observed by cyclic voltammetry, along with a reversible one-electron reduction wave at −0.85 V. Density functional calculations reproduce the experimentally observed data and trends, and provide further insight into the nature of the electronic transitions.
- Full Text:
- Date Issued: 2016