Challenges of post-apartheid state-owned company pension fund reform: a case study of the controversy around the Transnet-Transport Pension Fund
- Authors: Goqoza, Noluyolo Juliet
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/54766 , vital:26610
- Description: This thesis examines the restructuring of the pension funds of Transnet, a South African state-owned company involved in transportation, from the 1990s. Two of its main pension funds, the Transport-Transnet Pension sub-Fund (TTPF) and the Transnet Second Defined Benefit Fund (TSDBF), have been surrounded by controversy, with major court actions brought by aggrieved pensioners in 2006-2012 and again from 2013, and smaller cases in 1997-1999 and 2004. (There were also a number of smaller cases, mostly unsuccessful, but the thesis will not examine them). The case that started in 2013 is the biggest class action in the country‟s history, and makes claims of serious mismanagement and bad faith against the Transnet management. But the fundamental grievance is that (according to the 2013 legal case) “more than 80% of pensioners earn less than R4 000.00 a month… 62 % earn less than R2 500.00… 45% of the pensioners earn less than the state‟s ordinary old-age pension” grant for the poor. Although that case is ongoing, this thesis examines the background and controversies that frame the case. It provides an overview of the history and development of the South African pensions system and South African state-owned companies; it examines how these have been shaped by the apartheid and post-apartheid periods, and by the rise of neo-liberalism; it examines the evolution of Transnet and its pensions systems, from the early days of the South African Railways and Harbours Administration (SAR&H, formed 1910), to its restructuring into the South African Transport Services (SATS) in 1982, and then into Transnet in 1990. The thesis shows that the operations of the TTPF and TSDBF, which are closed to new members, have had serious effects on pensioners that rely upon them. Pensions are very low (the main reason for the various court cases), and this is for a range of reasons. Annual increases in pensions are formally set at below-inflation levels, leading to falling real incomes. More pressure on pensioners‟ livelihoods has arisen from Transnet‟s cuts to other benefits, like the medical aid Transmed, provided to pensioners. While the schemes are solvent, the pensions generally started at a low base, partly because most pensioners were relatively poorly paid workers before retirement (and the pensions were linked to former salaries). There is also a racial dimension: while most white workers at SAR&H/ SATS and Transnet were poorly paid, black, Coloured and Indian workers were paid even worse, and, further, were only brought into the pension schemes late. Both TTPF and TSDBF are defined benefit funds, which means members are guaranteed specific benefits at retirement, with the employer obligated to inject funds to meet shortfalls where needed. Yet neither the state nor Transnet has been willing to take actions to lift the basic pensions, such as investments into the funds, or to make systematic ex gratia payments to bring the pensions to a reasonable level, to remove historic racial inequalities between pensioners, to increase medical aid co-payments or coverage or to otherwise address the pensioners‟ situation. It does not seem that the reason for the problems is that the two funds have been severely mismanaged or asset-stripped, as alleged in the 2013 class action: it must be noted that both funds report surpluses. But the surpluses are possible because the pensions are low and falling in real terms, and the numbers of pensioners declining due to deaths. It seems clear that Transnet is unable or unwilling to act to decisively improve the situation of the pensioners: ensuring a surplus on existing pension funds is a major goal. This is partly because Transnet itself has ongoing financial problems, and partly because it operates in the context of neo-liberal restructuring, like corporatisation, commercialisation and privatisation, which places limits on the additional funding of the funds. At the same time, the pensioners have very little real, as opposed to a nominal, say in the administration of the pension schemes, limiting their ability to affect the rules and administration or raise issues. The thesis seeks to use historical institutionalism, which sees policies and major institutions, including state-owned companies, as shaped by power and conflict, especially between classes. This is used to try and explain changing state policies and the changing role and actions of state-owned companies, as a way of understanding Transnet‟s actions, as well as its treatment of its pensioners.
- Full Text:
- Date Issued: 2015
- Authors: Goqoza, Noluyolo Juliet
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/54766 , vital:26610
- Description: This thesis examines the restructuring of the pension funds of Transnet, a South African state-owned company involved in transportation, from the 1990s. Two of its main pension funds, the Transport-Transnet Pension sub-Fund (TTPF) and the Transnet Second Defined Benefit Fund (TSDBF), have been surrounded by controversy, with major court actions brought by aggrieved pensioners in 2006-2012 and again from 2013, and smaller cases in 1997-1999 and 2004. (There were also a number of smaller cases, mostly unsuccessful, but the thesis will not examine them). The case that started in 2013 is the biggest class action in the country‟s history, and makes claims of serious mismanagement and bad faith against the Transnet management. But the fundamental grievance is that (according to the 2013 legal case) “more than 80% of pensioners earn less than R4 000.00 a month… 62 % earn less than R2 500.00… 45% of the pensioners earn less than the state‟s ordinary old-age pension” grant for the poor. Although that case is ongoing, this thesis examines the background and controversies that frame the case. It provides an overview of the history and development of the South African pensions system and South African state-owned companies; it examines how these have been shaped by the apartheid and post-apartheid periods, and by the rise of neo-liberalism; it examines the evolution of Transnet and its pensions systems, from the early days of the South African Railways and Harbours Administration (SAR&H, formed 1910), to its restructuring into the South African Transport Services (SATS) in 1982, and then into Transnet in 1990. The thesis shows that the operations of the TTPF and TSDBF, which are closed to new members, have had serious effects on pensioners that rely upon them. Pensions are very low (the main reason for the various court cases), and this is for a range of reasons. Annual increases in pensions are formally set at below-inflation levels, leading to falling real incomes. More pressure on pensioners‟ livelihoods has arisen from Transnet‟s cuts to other benefits, like the medical aid Transmed, provided to pensioners. While the schemes are solvent, the pensions generally started at a low base, partly because most pensioners were relatively poorly paid workers before retirement (and the pensions were linked to former salaries). There is also a racial dimension: while most white workers at SAR&H/ SATS and Transnet were poorly paid, black, Coloured and Indian workers were paid even worse, and, further, were only brought into the pension schemes late. Both TTPF and TSDBF are defined benefit funds, which means members are guaranteed specific benefits at retirement, with the employer obligated to inject funds to meet shortfalls where needed. Yet neither the state nor Transnet has been willing to take actions to lift the basic pensions, such as investments into the funds, or to make systematic ex gratia payments to bring the pensions to a reasonable level, to remove historic racial inequalities between pensioners, to increase medical aid co-payments or coverage or to otherwise address the pensioners‟ situation. It does not seem that the reason for the problems is that the two funds have been severely mismanaged or asset-stripped, as alleged in the 2013 class action: it must be noted that both funds report surpluses. But the surpluses are possible because the pensions are low and falling in real terms, and the numbers of pensioners declining due to deaths. It seems clear that Transnet is unable or unwilling to act to decisively improve the situation of the pensioners: ensuring a surplus on existing pension funds is a major goal. This is partly because Transnet itself has ongoing financial problems, and partly because it operates in the context of neo-liberal restructuring, like corporatisation, commercialisation and privatisation, which places limits on the additional funding of the funds. At the same time, the pensioners have very little real, as opposed to a nominal, say in the administration of the pension schemes, limiting their ability to affect the rules and administration or raise issues. The thesis seeks to use historical institutionalism, which sees policies and major institutions, including state-owned companies, as shaped by power and conflict, especially between classes. This is used to try and explain changing state policies and the changing role and actions of state-owned companies, as a way of understanding Transnet‟s actions, as well as its treatment of its pensioners.
- Full Text:
- Date Issued: 2015
Change in Roviana Lagoon Coral Reef ethnobiology:
- Aswani, Shankar, Albert, Simon
- Authors: Aswani, Shankar , Albert, Simon
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/145460 , vital:38440 , ISBN 9783319237633 , DOI: 10.1007/978-3-319-23763-3_10
- Description: Coral reefs are iconic for their beauty and biodiversity, and are of great socioeconomic and cultural importance for many coastal communities across the tropics. However, little is known about people’s local classification and their social and ecological relationship with these habitats. This chapter describes Roviana people’s changing ecological and social relationship with their coral reefs, which are increasingly being damaged by humans. First, we combined ecological and social data to describe people’s classification of local coral reefs in tandem with the productive practices conducted in these habitats. Second, we examined local perceptions and recognized effects of environmental and climatic changes on reefs over the last two decades. Finally, we measured changes in fishing activities and in the taxonomic systems (between 1995 and 2011) to evaluate if recent social and economic change has led to the erosion of marine indigenous ecological knowledge and associated practices. Studying people’s changing perceptions of their coral reefs is crucial to understand their ability to identify and adapt to environmental transformations. Simply, the way local people perceive the state of the environment is not only important in terms of changes in local epistemology but also has important implications for how resources are used and managed, and this information can be coupled with scientific one for a broader management strategy.
- Full Text:
- Date Issued: 2015
- Authors: Aswani, Shankar , Albert, Simon
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/145460 , vital:38440 , ISBN 9783319237633 , DOI: 10.1007/978-3-319-23763-3_10
- Description: Coral reefs are iconic for their beauty and biodiversity, and are of great socioeconomic and cultural importance for many coastal communities across the tropics. However, little is known about people’s local classification and their social and ecological relationship with these habitats. This chapter describes Roviana people’s changing ecological and social relationship with their coral reefs, which are increasingly being damaged by humans. First, we combined ecological and social data to describe people’s classification of local coral reefs in tandem with the productive practices conducted in these habitats. Second, we examined local perceptions and recognized effects of environmental and climatic changes on reefs over the last two decades. Finally, we measured changes in fishing activities and in the taxonomic systems (between 1995 and 2011) to evaluate if recent social and economic change has led to the erosion of marine indigenous ecological knowledge and associated practices. Studying people’s changing perceptions of their coral reefs is crucial to understand their ability to identify and adapt to environmental transformations. Simply, the way local people perceive the state of the environment is not only important in terms of changes in local epistemology but also has important implications for how resources are used and managed, and this information can be coupled with scientific one for a broader management strategy.
- Full Text:
- Date Issued: 2015
Characterisation of the HSP70-HSP90 organising protein gene and its link to cancer
- Authors: Weeks, Stacey
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/56006 , vital:26764
- Description: HOP (Heat shock protein 70/ Heat shock protein 90 organising protein) is a co-chaperone essential for client protein transfer from HSP70 to HSP90 within the HSP90 chaperone machine and has been found to be up-regulated in various cancers. However, minimal in vitro information can be found on the regulation of HOP expression. The aim of this study was to analyse the HOP gene structure across known orthologues, identify and characterise the HOP promoter, and identify the regulatory mechanisms influencing the expression of HOP in cancer. We hypothesized that the expression of HOP in cancer cells is likely regulated by oncogenic signalling pathways linked to cis-elements within the HOP promoter. An initial study of the evolution of the HOP gene speciation was performed across identified orthologues using Mega5.2. The evolutionary pathway of the HOP gene was traced from the unicellular organisms to fish, to amphibian and then to land mammal. The synteny across the orthologues was identified and the co-expression profile of HOP analysed. We identified the putative promoter region for HOP in silico and in vitro. Luciferase reporter assays were utilized to demonstrate promoter activity of the upstream region in vitro. Bioinformatic analysis of the active promoter region identified a large CpG island and a range of putative cis-elements. Many of the cis-elements interact with transcription factors which are activated by oncogenic pathways. We therefore tested the regulation of HOP levels by rat sarcoma viral oncogene homologue (RAS). Cancer cell lines were transfected with mutated RAS to observe the effect of constitutively active RAS expression on the production of HOP using qRT-PCR and Western Blot analyses. Additionally, inhibitors of the RAS signalling pathway were utilised to confirm the regulatory effect of mutated RAS on HOP expression. In cancer cell lines containing mutated RAS (Hs578T), HOP was up-regulated via a mechanism involving the MAPK signalling pathway and the ETS-1 and C/EBPβ cis-elements within the HOP promoter. These findings suggest for the first time that Hop expression in cancer may be regulated by RAS activation of the HOP promoter. Additionally, this study allowed us to determine the murine system to be the most suited genetic model organism with which to study the function of human HOP.
- Full Text:
- Date Issued: 2015
- Authors: Weeks, Stacey
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/56006 , vital:26764
- Description: HOP (Heat shock protein 70/ Heat shock protein 90 organising protein) is a co-chaperone essential for client protein transfer from HSP70 to HSP90 within the HSP90 chaperone machine and has been found to be up-regulated in various cancers. However, minimal in vitro information can be found on the regulation of HOP expression. The aim of this study was to analyse the HOP gene structure across known orthologues, identify and characterise the HOP promoter, and identify the regulatory mechanisms influencing the expression of HOP in cancer. We hypothesized that the expression of HOP in cancer cells is likely regulated by oncogenic signalling pathways linked to cis-elements within the HOP promoter. An initial study of the evolution of the HOP gene speciation was performed across identified orthologues using Mega5.2. The evolutionary pathway of the HOP gene was traced from the unicellular organisms to fish, to amphibian and then to land mammal. The synteny across the orthologues was identified and the co-expression profile of HOP analysed. We identified the putative promoter region for HOP in silico and in vitro. Luciferase reporter assays were utilized to demonstrate promoter activity of the upstream region in vitro. Bioinformatic analysis of the active promoter region identified a large CpG island and a range of putative cis-elements. Many of the cis-elements interact with transcription factors which are activated by oncogenic pathways. We therefore tested the regulation of HOP levels by rat sarcoma viral oncogene homologue (RAS). Cancer cell lines were transfected with mutated RAS to observe the effect of constitutively active RAS expression on the production of HOP using qRT-PCR and Western Blot analyses. Additionally, inhibitors of the RAS signalling pathway were utilised to confirm the regulatory effect of mutated RAS on HOP expression. In cancer cell lines containing mutated RAS (Hs578T), HOP was up-regulated via a mechanism involving the MAPK signalling pathway and the ETS-1 and C/EBPβ cis-elements within the HOP promoter. These findings suggest for the first time that Hop expression in cancer may be regulated by RAS activation of the HOP promoter. Additionally, this study allowed us to determine the murine system to be the most suited genetic model organism with which to study the function of human HOP.
- Full Text:
- Date Issued: 2015
Characterization and analysis of NTP amplification based DDoS attacks
- Rudman, Lauren, Irwin, Barry V W
- Authors: Rudman, Lauren , Irwin, Barry V W
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429285 , vital:72573 , 10.1109/ISSA.2015.7335069
- Description: Network Time Protocol based DDoS attacks saw a lot of popularity throughout 2014. This paper shows the characterization and analysis of two large datasets containing packets from NTP based DDoS attacks captured in South Africa. Using a series of Python based tools, the dataset is analysed according to specific parts of the packet headers. These include the source IP address and Time-to-live (TTL) values. The analysis found the top source addresses and looked at the TTL values observed for each address. These TTL values can be used to calculate the probable operating system or DDoS attack tool used by an attacker. We found that each TTL value seen for an address can indicate the number of hosts attacking the address or indicate minor routing changes. The Time-to-Live values, as a whole, are then analysed to find the total number used throughout each attack. The most frequent TTL values are then found and show that the migratory of them indicate the attackers are using an initial TTL of 255. This value can indicate the use of a certain DDoS tool that creates packets with that exact initial TTL. The TTL values are then put into groups that can show the number of IP addresses a group of hosts are targeting.
- Full Text:
- Date Issued: 2015
- Authors: Rudman, Lauren , Irwin, Barry V W
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429285 , vital:72573 , 10.1109/ISSA.2015.7335069
- Description: Network Time Protocol based DDoS attacks saw a lot of popularity throughout 2014. This paper shows the characterization and analysis of two large datasets containing packets from NTP based DDoS attacks captured in South Africa. Using a series of Python based tools, the dataset is analysed according to specific parts of the packet headers. These include the source IP address and Time-to-live (TTL) values. The analysis found the top source addresses and looked at the TTL values observed for each address. These TTL values can be used to calculate the probable operating system or DDoS attack tool used by an attacker. We found that each TTL value seen for an address can indicate the number of hosts attacking the address or indicate minor routing changes. The Time-to-Live values, as a whole, are then analysed to find the total number used throughout each attack. The most frequent TTL values are then found and show that the migratory of them indicate the attackers are using an initial TTL of 255. This value can indicate the use of a certain DDoS tool that creates packets with that exact initial TTL. The TTL values are then put into groups that can show the number of IP addresses a group of hosts are targeting.
- Full Text:
- Date Issued: 2015
Characterization of porphyrin nanorods on fluorine doped tin oxide glass sheet
- George, Reama C, Falgenhauer, Jane, Geis, Clemens, Nyokong, Tebello, Schlettwein, Derck
- Authors: George, Reama C , Falgenhauer, Jane , Geis, Clemens , Nyokong, Tebello , Schlettwein, Derck
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193542 , vital:45344 , xlink:href="https://doi.org/10.1142/S1088424615500923"
- Description: Porphyrin nanorods (PNR) have been fabricated by electrostatic self-assembly of two oppositely charged porphyrin molecules. The free base meso-tetra-(4-phenylsulphonate) porphyrin (TPPS4)4) served as negatively charged counterpart for the positively charged metallo meso-tetra(4-NN-methylpyridyl) porphyrins (MTM’PyP) with either Sn, Co, Mn or In as central metal M. Films of PNR were prepared on fluorine doped tin oxide glass sheets (FTO) by using a drop-dry method. The electronic spectra revealed J-aggregation of the charged molecules for the colloid PNR as well as for the films. Transmission electron microscopy confirmed the formation of porphyrin nanorods. The laser microscope and scanning electron microscope (SEM) images of the PNR/FTO films showed the formation of three kinds of structures in the films which consist of differently branched or linear needles with their main axis grown in the direction of the solvent flow during preparation. During cyclic voltammetry either applying negative potentials from 0.0 V to -1.0 V or positive potentials from 0.0 V to ++2.2 V irreversible reduction or oxidation reactions were detected for the films. Consistently, SEM images taken following cyclic voltammetry showed the disintegration of the PNR on the films into smaller subunits. Spectroelectrochemical measurements showed the formation of porphyrin anionic radicals during oxidation by a decrease in the absorption intensities and broadening of spectra with an additional band appearing around 900 nm. A similar trend was observed when negative potentials were applied but in this case the cationic radical was produced. In both cases the decrease of the intensity of the J-aggregate confirms a loss of intermolecular coupling, again consistent with the smaller subunits observed in SEM analysis.
- Full Text:
- Date Issued: 2015
- Authors: George, Reama C , Falgenhauer, Jane , Geis, Clemens , Nyokong, Tebello , Schlettwein, Derck
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193542 , vital:45344 , xlink:href="https://doi.org/10.1142/S1088424615500923"
- Description: Porphyrin nanorods (PNR) have been fabricated by electrostatic self-assembly of two oppositely charged porphyrin molecules. The free base meso-tetra-(4-phenylsulphonate) porphyrin (TPPS4)4) served as negatively charged counterpart for the positively charged metallo meso-tetra(4-NN-methylpyridyl) porphyrins (MTM’PyP) with either Sn, Co, Mn or In as central metal M. Films of PNR were prepared on fluorine doped tin oxide glass sheets (FTO) by using a drop-dry method. The electronic spectra revealed J-aggregation of the charged molecules for the colloid PNR as well as for the films. Transmission electron microscopy confirmed the formation of porphyrin nanorods. The laser microscope and scanning electron microscope (SEM) images of the PNR/FTO films showed the formation of three kinds of structures in the films which consist of differently branched or linear needles with their main axis grown in the direction of the solvent flow during preparation. During cyclic voltammetry either applying negative potentials from 0.0 V to -1.0 V or positive potentials from 0.0 V to ++2.2 V irreversible reduction or oxidation reactions were detected for the films. Consistently, SEM images taken following cyclic voltammetry showed the disintegration of the PNR on the films into smaller subunits. Spectroelectrochemical measurements showed the formation of porphyrin anionic radicals during oxidation by a decrease in the absorption intensities and broadening of spectra with an additional band appearing around 900 nm. A similar trend was observed when negative potentials were applied but in this case the cationic radical was produced. In both cases the decrease of the intensity of the J-aggregate confirms a loss of intermolecular coupling, again consistent with the smaller subunits observed in SEM analysis.
- Full Text:
- Date Issued: 2015
Characterization of some amino acid derivatives of benzoyl isothiocyanate: Crystal structures and theoretical prediction of their reactivity
- Odame, Felix, Hosten, Eric C, Betz, Richard, Lobb, Kevin A, Tshentu, Zenixole R
- Authors: Odame, Felix , Hosten, Eric C , Betz, Richard , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447952 , vital:74686 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.05.053"
- Description: The reaction of benzoyl isothiocyanate with L-serine, L-proline, D-methionine and L-alanine gave 2-[(benzoylcarbamothioyl)amino]-3-hydroxypropanoic acid (I), 1-(benzoylcarbamothioyl)pyrrolidine-2-carboxylic acid (II), 2-[(benzoylcarbamothioyl)amino]-4-(methylsulfanyl)butanoic acid (III) and 2-[(benzoylcarbamothioyl)amino]propanoic acid (IV), respectively. The compounds have been characterized by IR, NMR, microanalyses and mass spectrometry. The crystal structures of all the compounds have also been discussed. Compound II showed rotamers in solution. DFT calculations of the frontier orbitals of the compounds have been carried out to ascertain the groups that contribute to the HOMO and LUMO, and to study their contribution to the reactivity of these compounds. The calculations indicated that the carboxylic acid group in these compounds is unreactive hence making the conversion to benzimidazoles via cyclization on the carboxylic acids impractical. This has been further confirmed by the reaction of compounds I–IV, respectively, with o-phenylene diamine which was unsuccessful but gave compound V.
- Full Text:
- Date Issued: 2015
- Authors: Odame, Felix , Hosten, Eric C , Betz, Richard , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447952 , vital:74686 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.05.053"
- Description: The reaction of benzoyl isothiocyanate with L-serine, L-proline, D-methionine and L-alanine gave 2-[(benzoylcarbamothioyl)amino]-3-hydroxypropanoic acid (I), 1-(benzoylcarbamothioyl)pyrrolidine-2-carboxylic acid (II), 2-[(benzoylcarbamothioyl)amino]-4-(methylsulfanyl)butanoic acid (III) and 2-[(benzoylcarbamothioyl)amino]propanoic acid (IV), respectively. The compounds have been characterized by IR, NMR, microanalyses and mass spectrometry. The crystal structures of all the compounds have also been discussed. Compound II showed rotamers in solution. DFT calculations of the frontier orbitals of the compounds have been carried out to ascertain the groups that contribute to the HOMO and LUMO, and to study their contribution to the reactivity of these compounds. The calculations indicated that the carboxylic acid group in these compounds is unreactive hence making the conversion to benzimidazoles via cyclization on the carboxylic acids impractical. This has been further confirmed by the reaction of compounds I–IV, respectively, with o-phenylene diamine which was unsuccessful but gave compound V.
- Full Text:
- Date Issued: 2015
Characterization of the co-chaperones of Hsp70 and Hsp90 in Trypanosoma brucei and their potential partnerships
- Authors: Mokoena, Fortunate
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54543 , vital:26583
- Description: African Trypanosomiasis, which is caused by Trypanosoma brucei, is one of the crippling agents of social and economic development in Africa. T. brucei cycles between the cold-blooded insect vector, the tsetse fly (Glossina spp), and warm-blooded mammalian hosts. T. brucei, T. cruzi and L. major are mammal infecting kinetoplastid parasites that are collectively referred to as TriTryps. These parasites experience extreme environments as they move between their warm-blooded mammalian hosts and cold-blooded insect vectors which trigger extensive morphological transformations during the life-cycle of the parasite. Molecular chaperones have been implicated in parasite differentiation. TriTryps display significant expansions and diversity in the gene complements encoding molecular chaperones, especially J-proteins. Generally, J-proteins function as co-chaperones of Hsp70s, forming part of vital protein homeostasis processes. Hsp70s show a high degree of conservation, while J-proteins appear to be an extreme case of taxonomic radiation. Although several studies have focused on the molecular and cell biology of Hsp70s in some kinetoplastid parasites, knowledge is still lacking pertaining to J-proteins and their partnerships with Hsp70s. This thesis focused on the classification of kinetoplastid Jproteins into the four types by examining the domain organizations using T. brucei as a guide. The potential partnership of J-proteins and Hsp70s were postulated based on predicted subcellular localization. Kinetoplastid parasites, particularly T. brucei, have evolved an expanded and specialized J-protein machinery, likely to be a consequence of an evolutionary fitness/trait to adapt to diverse environment present in hosts and vectors. These analyses will yield insight into the process of parasite differentiation as well as provide new leads for chemotherapeutic treatments. The presence of the STI1 mediated Hsp90 hetero-complex formation has not been confirmed in T. brucei. To this end, in silico and biochemical techniques were used to characterize the role of TbSTI1, as an adaptor protein of Hsp70 and Hsp90. Through domain architecture analysis, sequence alignments, phylogenetic analysis and three-dimensional structure prediction, TbSTI1 was demonstrated to be the most conserved TPR containing co-chaperone of Hsp70 and Hsp83 in T. brucei and also shown to be highly similar to its eukaryotic homologues. Recombinant TbSTI1 was overproduced and purified in E.coli cells and subsequently shown to associate with TcHsp70 in a concentration dependent manner and associate weakly with TbHsp70.4. TbSTI1 and TbHsp83 were also demonstrated to be expressed and upregulated upon exposure to heat shock at the bloodstream stage of parasite development. In conclusion, this study is the first to report the interaction of TbSTI1 with a chaperone. Interactions between TbSTI1 and Hsp70s were demonstrated and therefore, the formation of the hetero-complex is predicted based the similarity of TbSTI1 to other STI1 proteins.
- Full Text:
- Date Issued: 2015
- Authors: Mokoena, Fortunate
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54543 , vital:26583
- Description: African Trypanosomiasis, which is caused by Trypanosoma brucei, is one of the crippling agents of social and economic development in Africa. T. brucei cycles between the cold-blooded insect vector, the tsetse fly (Glossina spp), and warm-blooded mammalian hosts. T. brucei, T. cruzi and L. major are mammal infecting kinetoplastid parasites that are collectively referred to as TriTryps. These parasites experience extreme environments as they move between their warm-blooded mammalian hosts and cold-blooded insect vectors which trigger extensive morphological transformations during the life-cycle of the parasite. Molecular chaperones have been implicated in parasite differentiation. TriTryps display significant expansions and diversity in the gene complements encoding molecular chaperones, especially J-proteins. Generally, J-proteins function as co-chaperones of Hsp70s, forming part of vital protein homeostasis processes. Hsp70s show a high degree of conservation, while J-proteins appear to be an extreme case of taxonomic radiation. Although several studies have focused on the molecular and cell biology of Hsp70s in some kinetoplastid parasites, knowledge is still lacking pertaining to J-proteins and their partnerships with Hsp70s. This thesis focused on the classification of kinetoplastid Jproteins into the four types by examining the domain organizations using T. brucei as a guide. The potential partnership of J-proteins and Hsp70s were postulated based on predicted subcellular localization. Kinetoplastid parasites, particularly T. brucei, have evolved an expanded and specialized J-protein machinery, likely to be a consequence of an evolutionary fitness/trait to adapt to diverse environment present in hosts and vectors. These analyses will yield insight into the process of parasite differentiation as well as provide new leads for chemotherapeutic treatments. The presence of the STI1 mediated Hsp90 hetero-complex formation has not been confirmed in T. brucei. To this end, in silico and biochemical techniques were used to characterize the role of TbSTI1, as an adaptor protein of Hsp70 and Hsp90. Through domain architecture analysis, sequence alignments, phylogenetic analysis and three-dimensional structure prediction, TbSTI1 was demonstrated to be the most conserved TPR containing co-chaperone of Hsp70 and Hsp83 in T. brucei and also shown to be highly similar to its eukaryotic homologues. Recombinant TbSTI1 was overproduced and purified in E.coli cells and subsequently shown to associate with TcHsp70 in a concentration dependent manner and associate weakly with TbHsp70.4. TbSTI1 and TbHsp83 were also demonstrated to be expressed and upregulated upon exposure to heat shock at the bloodstream stage of parasite development. In conclusion, this study is the first to report the interaction of TbSTI1 with a chaperone. Interactions between TbSTI1 and Hsp70s were demonstrated and therefore, the formation of the hetero-complex is predicted based the similarity of TbSTI1 to other STI1 proteins.
- Full Text:
- Date Issued: 2015
CHIP: a co-chaperone for degradation by the proteasome
- Authors: Edkins, Adrienne L
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/164863 , vital:41179 , ISBN 978-3-319-11730-0 , DOI: 10.1007/978-3-319-11731-7_11
- Description: Protein homeostasis relies on a balance between protein folding and protein degradation. Molecular chaperones like Hsp70 and Hsp90 fulfil well-defined roles in protein folding and conformational stability via ATP dependent reaction cycles. These folding cycles are controlled by associations with a cohort of non-client protein co-chaperones, such as Hop, p23 and Aha1. Pro-folding co-chaperones facilitate the transit of the client protein through the chaperone mediated folding process. However, chaperones are also involved in ubiquitin-mediated proteasomal degradation of client proteins. Similar to folding complexes, the ability of chaperones to mediate protein degradation is regulated by co-chaperones, such as the C terminal Hsp70 binding protein (CHIP).
- Full Text:
- Date Issued: 2015
- Authors: Edkins, Adrienne L
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/164863 , vital:41179 , ISBN 978-3-319-11730-0 , DOI: 10.1007/978-3-319-11731-7_11
- Description: Protein homeostasis relies on a balance between protein folding and protein degradation. Molecular chaperones like Hsp70 and Hsp90 fulfil well-defined roles in protein folding and conformational stability via ATP dependent reaction cycles. These folding cycles are controlled by associations with a cohort of non-client protein co-chaperones, such as Hop, p23 and Aha1. Pro-folding co-chaperones facilitate the transit of the client protein through the chaperone mediated folding process. However, chaperones are also involved in ubiquitin-mediated proteasomal degradation of client proteins. Similar to folding complexes, the ability of chaperones to mediate protein degradation is regulated by co-chaperones, such as the C terminal Hsp70 binding protein (CHIP).
- Full Text:
- Date Issued: 2015
Classification System for Wetlands and Other Aquatic Ecosystems in South Africa:
- Authors: Ellery, William F N
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144454 , vital:38347 , https://doi.org/10.2989/10220119.2015.1025843
- Description: There have been several attempts to develop a wetland classification for South Africa, with merit in each, but a system that satisfies the needs of a wide range of professionals has been elusive. This is partly to be expected since classification systems are often user-specific. Nevertheless, and at last, the authors of Classification System for Wetlands and Other Aquatic Ecosystems in South Africa. User Manual: Inland Systems (SANBI Biodiversity Series 22) have developed a robust and comprehensive wetland classification system for South Africa that likely will have broad appeal and be widely used. Working for Wetlands, the Water Research Commission (WRC) and SANBI provided considerable support for the development of this system and there was expert input from a wide range of stakeholders.
- Full Text:
- Date Issued: 2015
- Authors: Ellery, William F N
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144454 , vital:38347 , https://doi.org/10.2989/10220119.2015.1025843
- Description: There have been several attempts to develop a wetland classification for South Africa, with merit in each, but a system that satisfies the needs of a wide range of professionals has been elusive. This is partly to be expected since classification systems are often user-specific. Nevertheless, and at last, the authors of Classification System for Wetlands and Other Aquatic Ecosystems in South Africa. User Manual: Inland Systems (SANBI Biodiversity Series 22) have developed a robust and comprehensive wetland classification system for South Africa that likely will have broad appeal and be widely used. Working for Wetlands, the Water Research Commission (WRC) and SANBI provided considerable support for the development of this system and there was expert input from a wide range of stakeholders.
- Full Text:
- Date Issued: 2015
Comparative electrocatalytic studies of nanocomposites of mixed and covalently linked multiwalled carbon nanotubes and 4-(4, 6-diaminopyrimidin-2-ylthio) phthalocyaninato cobalt (II)
- Nyoni, Stephen, Nyokong, Tebello
- Authors: Nyoni, Stephen , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189285 , vital:44834 , xlink:href="https://doi.org/10.1016/j.poly.2015.05.038"
- Description: Electrocatalytic behavior of 4-(4,6-diaminopyrimidin-2-ylthio) phthalocyaninato cobalt(II) (CoPyPc) when mixed or covalently mixed to multiwalled carbon nanotubes (MWCNTs) is reported. Infra-red spectroscopy was used to confirm amide linkage of the covalently linked nanocomposite. Rotating disk electrode (RDE) and cyclic (CV) voltammetry studies were used for the electrochemical characterization of the prepared phthalocyanine and MWCNT nanocomposite. The electrocatalytic effects of the nanocomposites of the cobalt phthalocyanine derivative were then investigated towards L-cysteine oxidation using both RDE and CV experiments, and the electrocatalytic performance of the covalently linked cobalt phthalocyanine-MWCNT was found to be superior over the mixed nanocomposite.
- Full Text:
- Date Issued: 2015
- Authors: Nyoni, Stephen , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189285 , vital:44834 , xlink:href="https://doi.org/10.1016/j.poly.2015.05.038"
- Description: Electrocatalytic behavior of 4-(4,6-diaminopyrimidin-2-ylthio) phthalocyaninato cobalt(II) (CoPyPc) when mixed or covalently mixed to multiwalled carbon nanotubes (MWCNTs) is reported. Infra-red spectroscopy was used to confirm amide linkage of the covalently linked nanocomposite. Rotating disk electrode (RDE) and cyclic (CV) voltammetry studies were used for the electrochemical characterization of the prepared phthalocyanine and MWCNT nanocomposite. The electrocatalytic effects of the nanocomposites of the cobalt phthalocyanine derivative were then investigated towards L-cysteine oxidation using both RDE and CV experiments, and the electrocatalytic performance of the covalently linked cobalt phthalocyanine-MWCNT was found to be superior over the mixed nanocomposite.
- Full Text:
- Date Issued: 2015
Comparative photophysicochemical behavior of nanoconjugates of indium tetracarboxyphenoxy phthalocyanines covalently linked to CdTe/ZnSe/ZnO quantum dots
- Oluwole, David O, Nyokong, Tebello
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: vital:7294 , http://hdl.handle.net/10962/d1020357 , http://dx.doi.org/10.1016/j.jphotochem.2015.07.009
- Description: This work reports on the photophysicochemical behavior of different nanoconjugates of core/shell/shell (GSH-CdTe/ZnSe/ZnO), core/shell (GSH-CdTe/ZnSe) and core (GSH-CdTe) (quantum dots QDs) with indium tetracarboxyphenoxy phthalocyanines ((OH)InTCPPc) in dimethylsulfoxide. The fluorescence quantum yields (Φf) and lifetimes (τf, in brackets) of QDs ranged from 0.20 (13.9 ns) to 0.42 (25.6 ns). The highest Φf value was obtained for GSH-CdTe/ZnSe/ZnO (4.5) while the least was observed in GSH-CdTe/ZnSe/ZnO (7.6), the numbers in brackets refer to the sizes. For (OH)InTCPPc alone a Φf and τf values of 0.02 and 2.43 ns, respectively were obtained. In the nanoconjugates, pivotal decrease in the Φf and τf of the QDs were observed with increase in the triplet and singlet oxygen quantum yields of (OH)InTCPPc. , Original publication is available at http://dx.doi.org/10.1016/j.jphotochem.2015.07.009
- Full Text: false
- Date Issued: 2015
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: vital:7294 , http://hdl.handle.net/10962/d1020357 , http://dx.doi.org/10.1016/j.jphotochem.2015.07.009
- Description: This work reports on the photophysicochemical behavior of different nanoconjugates of core/shell/shell (GSH-CdTe/ZnSe/ZnO), core/shell (GSH-CdTe/ZnSe) and core (GSH-CdTe) (quantum dots QDs) with indium tetracarboxyphenoxy phthalocyanines ((OH)InTCPPc) in dimethylsulfoxide. The fluorescence quantum yields (Φf) and lifetimes (τf, in brackets) of QDs ranged from 0.20 (13.9 ns) to 0.42 (25.6 ns). The highest Φf value was obtained for GSH-CdTe/ZnSe/ZnO (4.5) while the least was observed in GSH-CdTe/ZnSe/ZnO (7.6), the numbers in brackets refer to the sizes. For (OH)InTCPPc alone a Φf and τf values of 0.02 and 2.43 ns, respectively were obtained. In the nanoconjugates, pivotal decrease in the Φf and τf of the QDs were observed with increase in the triplet and singlet oxygen quantum yields of (OH)InTCPPc. , Original publication is available at http://dx.doi.org/10.1016/j.jphotochem.2015.07.009
- Full Text: false
- Date Issued: 2015
Comparison between Endothelin, Nitric Oxide and their Association to Blood Pressure and Body Composition in HIV Patients, in Mthatha
- Authors: Zono, Sinethemba
- Date: 2015
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/2909 , vital:43105
- Description: Background: Dysfunction of the vascular endothelium is an early finding in the progression of cardiovascular disease and is closely related to clinical events in patients with obesity and hypertension. Vascular function is mediated by nitric oxide (NO) and endothelin (ET-1) which serve as natural counterparts. The aim of the study was to determine the physiological effects of HIV infection, blood pressure and body composition on the changes of ET-1 and NO and association between ET-1 and NO. Methods and results: This was a descriptive and comparative study. A Quota sample method was used. The study population consisted of 154 participants categorized into the following groups: 57 HIV negative participants (A), 40 HIV positive not on treatment participants and 57 HIV positive on treatment participants. Enzyme immunoassay kit was used for the quantitative determination of ET-1 and Nitrate/nitrite colorimetric assay kit was used for the determination of NO. Anthropometric measurements, body composition were determined. Hemodynamic measurements were also taken into account. Results: Resting metabolism, waist circumference (WC) and hip circumference had low mean levels in both HIV positives groups compared to HIV negative group. On lipid profiles visceral fat (VF), whole fat (WF) had low mean levels but skeletal muscle fat (SMF) showed the highest mean levels in both HIV positive groups. All the blood pressures between HIV groups were on a normal range scale. Mean values of endothelin and nitric oxide are increased in HIV positive not on ART and HIV (+) on ART compared with the HIV negative group. Conclusion: NO, ET-1, ART and HIV itself were associated with the pathogenesis of endothelial dysfunction in persons with HIV infection. Elevated endothelial markers namely ET-1 and NO can lead to improvement of endothelium dependent relaxation to some extent but not completely. Although these markers have deleterious effect on the endothelium but can also serve as up-regulator of hypertension. Key words: HIV-infection, antiretroviral therapy, endothelial dysfunction, Endothelin1 (ET-1), nitric oxide (NO), blood pressures (BPs). , Thesis (MSc) -- Faculty of Health Sciences, 2015
- Full Text:
- Date Issued: 2015
- Authors: Zono, Sinethemba
- Date: 2015
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/2909 , vital:43105
- Description: Background: Dysfunction of the vascular endothelium is an early finding in the progression of cardiovascular disease and is closely related to clinical events in patients with obesity and hypertension. Vascular function is mediated by nitric oxide (NO) and endothelin (ET-1) which serve as natural counterparts. The aim of the study was to determine the physiological effects of HIV infection, blood pressure and body composition on the changes of ET-1 and NO and association between ET-1 and NO. Methods and results: This was a descriptive and comparative study. A Quota sample method was used. The study population consisted of 154 participants categorized into the following groups: 57 HIV negative participants (A), 40 HIV positive not on treatment participants and 57 HIV positive on treatment participants. Enzyme immunoassay kit was used for the quantitative determination of ET-1 and Nitrate/nitrite colorimetric assay kit was used for the determination of NO. Anthropometric measurements, body composition were determined. Hemodynamic measurements were also taken into account. Results: Resting metabolism, waist circumference (WC) and hip circumference had low mean levels in both HIV positives groups compared to HIV negative group. On lipid profiles visceral fat (VF), whole fat (WF) had low mean levels but skeletal muscle fat (SMF) showed the highest mean levels in both HIV positive groups. All the blood pressures between HIV groups were on a normal range scale. Mean values of endothelin and nitric oxide are increased in HIV positive not on ART and HIV (+) on ART compared with the HIV negative group. Conclusion: NO, ET-1, ART and HIV itself were associated with the pathogenesis of endothelial dysfunction in persons with HIV infection. Elevated endothelial markers namely ET-1 and NO can lead to improvement of endothelium dependent relaxation to some extent but not completely. Although these markers have deleterious effect on the endothelium but can also serve as up-regulator of hypertension. Key words: HIV-infection, antiretroviral therapy, endothelial dysfunction, Endothelin1 (ET-1), nitric oxide (NO), blood pressures (BPs). , Thesis (MSc) -- Faculty of Health Sciences, 2015
- Full Text:
- Date Issued: 2015
Comparisons of isotopic niche widths of some invasive and indigenous fauna in a South African river
- Hill, Jaclyn M, Jones, Roy W, Hill, Martin P, Weyl, Olaf L F
- Authors: Hill, Jaclyn M , Jones, Roy W , Hill, Martin P , Weyl, Olaf L F
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423711 , vital:72088 , xlink:href="https://doi.org/10.1111/fwb.12542"
- Description: Biological invasions threaten ecosystem integrity and bio-diversity, with numerous adverse implications for native flora and fauna. Established populations of two notorious freshwater invaders, the snail Tarebia granifera and the fish Pterygoplichthys disjunctivus, have been reported on three continents and are frequently predicted to be in di-rect competition with native species for dietary resources.
- Full Text:
- Date Issued: 2015
- Authors: Hill, Jaclyn M , Jones, Roy W , Hill, Martin P , Weyl, Olaf L F
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423711 , vital:72088 , xlink:href="https://doi.org/10.1111/fwb.12542"
- Description: Biological invasions threaten ecosystem integrity and bio-diversity, with numerous adverse implications for native flora and fauna. Established populations of two notorious freshwater invaders, the snail Tarebia granifera and the fish Pterygoplichthys disjunctivus, have been reported on three continents and are frequently predicted to be in di-rect competition with native species for dietary resources.
- Full Text:
- Date Issued: 2015
Condoms in pockets and HIV-free certificates: mother-daughter communication about sex and risk in a time of AIDS epidemic in South Africa
- Authors: Wilbraham, Lindy
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143693 , vital:38274 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Responsive to the perceived high risks of sexual coercion, unwanted pregnancy and HIV-infection of girls in particular, several South African sexual health promotion campaigns have used media targeting parents (mothers in particular) to instruct them on how sex should be talked about with young people to ‘risk-proof’ them. Such an instrumentalist public health discourse posits this intergenerational communication as an ‘ongoing discussion’ of events, feelings, issues and risk-safe practices around heterosexual sex negotiation. A Foucauldian view finds these conversational imperatives pitched against much-talked-about resistances to talking about sex; and the saturation with risk of ambivalent mothers and silent daughters. Mother-daughter communication about sex and sexualities – as an uneasy western ideal of attachment parenting – has tangled roots in psychoanalytic theory and feminisms where sex as the core of modern subjectivity is normalized, capacities for intimacy are trained, and affiliative sexuality is modelled in ways that balance the rights and responsibilities of sexual agency/citizenship. This paper begins with two narrative fragments from a sexual health campaign that addressed mothers and daughters, and recounts how these ‘stories’ produced derisive laughter when introduced into group discussions with young/older women. The paper follows two lines of exploration. Firstly, is western idealized fabrication of inter-subjectivity between mothers and daughters desirable and feasible in post-apartheid conditions of epidemic in South Africa? And secondly, what if the narratives of lives and experiences we offer by way of health education materials provoke uncertainties, gaps and interrogations about sex, mothering and communication, instead of offering homilies and solutions?
- Full Text:
- Date Issued: 2015
- Authors: Wilbraham, Lindy
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143693 , vital:38274 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Responsive to the perceived high risks of sexual coercion, unwanted pregnancy and HIV-infection of girls in particular, several South African sexual health promotion campaigns have used media targeting parents (mothers in particular) to instruct them on how sex should be talked about with young people to ‘risk-proof’ them. Such an instrumentalist public health discourse posits this intergenerational communication as an ‘ongoing discussion’ of events, feelings, issues and risk-safe practices around heterosexual sex negotiation. A Foucauldian view finds these conversational imperatives pitched against much-talked-about resistances to talking about sex; and the saturation with risk of ambivalent mothers and silent daughters. Mother-daughter communication about sex and sexualities – as an uneasy western ideal of attachment parenting – has tangled roots in psychoanalytic theory and feminisms where sex as the core of modern subjectivity is normalized, capacities for intimacy are trained, and affiliative sexuality is modelled in ways that balance the rights and responsibilities of sexual agency/citizenship. This paper begins with two narrative fragments from a sexual health campaign that addressed mothers and daughters, and recounts how these ‘stories’ produced derisive laughter when introduced into group discussions with young/older women. The paper follows two lines of exploration. Firstly, is western idealized fabrication of inter-subjectivity between mothers and daughters desirable and feasible in post-apartheid conditions of epidemic in South Africa? And secondly, what if the narratives of lives and experiences we offer by way of health education materials provoke uncertainties, gaps and interrogations about sex, mothering and communication, instead of offering homilies and solutions?
- Full Text:
- Date Issued: 2015
Connectivity through allochthony: Reciprocal links between adjacent aquatic and terrestrial ecosystems in South Africa
- Richoux, Nicole B, Moyo, Sydney, Chari, Lenin D, Bergamino, Leandro, Carassou, Laure, Dalu, Tatenda, Hean, Jeff W, Sikutshwa, Likho, Gininda, Simphiwe, Magoro, Mandla, Perhar, Gurbir, Ni, Felicity, Villet, Martin H, Whitfield, Alan K, Parker, Daniel M, Froneman, P William, Arhonditsis, George, Craig, Adrian J F K
- Authors: Richoux, Nicole B , Moyo, Sydney , Chari, Lenin D , Bergamino, Leandro , Carassou, Laure , Dalu, Tatenda , Hean, Jeff W , Sikutshwa, Likho , Gininda, Simphiwe , Magoro, Mandla , Perhar, Gurbir , Ni, Felicity , Villet, Martin H , Whitfield, Alan K , Parker, Daniel M , Froneman, P William , Arhonditsis, George , Craig, Adrian J F K
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438363 , vital:73454 , ISBN 978-1-4312-0679-7 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2186-1-15.pdf
- Description: An important aspect of the dynamics of nutrients and pollutants in natural systems is captured in the concept of allochthony, founded on the observation that nutrients and energy in a variety of forms are transferred between adjacent habitats, com-munities and ecosystems that are not routinely considered as connected. Different forms of nutrients and energy move across the conceptual boundaries of habitats via organisms’ activities or physical processes such as wind or water currents, and these transfers can represent important food subsidies. Such cross-partition ecolog-ical subsidies can augment the nutritional condition, biomass and biodiversity of communities, particularly where local production (or autochthony) alone may be inadequate to support local food webs. Furthermore, organic subsidies can influ-ence population dynamics, community interactions and ecosystem processes, and can represent dominant flux inputs in ecosystem budgets. Our intention was to ex-plore organic nutrient fluxes in relation to a primarily lotic (i.e. flowing) aquatic sys-tem at the scale of a hydrological catchment.
- Full Text:
- Date Issued: 2015
- Authors: Richoux, Nicole B , Moyo, Sydney , Chari, Lenin D , Bergamino, Leandro , Carassou, Laure , Dalu, Tatenda , Hean, Jeff W , Sikutshwa, Likho , Gininda, Simphiwe , Magoro, Mandla , Perhar, Gurbir , Ni, Felicity , Villet, Martin H , Whitfield, Alan K , Parker, Daniel M , Froneman, P William , Arhonditsis, George , Craig, Adrian J F K
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438363 , vital:73454 , ISBN 978-1-4312-0679-7 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2186-1-15.pdf
- Description: An important aspect of the dynamics of nutrients and pollutants in natural systems is captured in the concept of allochthony, founded on the observation that nutrients and energy in a variety of forms are transferred between adjacent habitats, com-munities and ecosystems that are not routinely considered as connected. Different forms of nutrients and energy move across the conceptual boundaries of habitats via organisms’ activities or physical processes such as wind or water currents, and these transfers can represent important food subsidies. Such cross-partition ecolog-ical subsidies can augment the nutritional condition, biomass and biodiversity of communities, particularly where local production (or autochthony) alone may be inadequate to support local food webs. Furthermore, organic subsidies can influ-ence population dynamics, community interactions and ecosystem processes, and can represent dominant flux inputs in ecosystem budgets. Our intention was to ex-plore organic nutrient fluxes in relation to a primarily lotic (i.e. flowing) aquatic sys-tem at the scale of a hydrological catchment.
- Full Text:
- Date Issued: 2015
Constructing sexualities: a critical overview of articles published in Feminism and Psychology
- Marx, Jacqueline, Donaldson, Natalie
- Authors: Marx, Jacqueline , Donaldson, Natalie
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142040 , vital:38044 , DOI: 10.1177/0959353515572704
- Description: How have sexualities been dealt with in articles published in Feminism and Psychology since the inception of the journal in 1991? The idea for this overview arose from our experience of designing a critical sexualities course for graduate students in psychology. The articles featured in this overview form part of a Virtual Special Issue that can be located on the Feminism and Psychology website. Virtual Special Issues (VSI) are collections of previously published articles, which have been compiled by guest editors who are experts in the field. VSIs provide readers with an overview of feminist thought about a topic or theme, as well as an easy way to locate pertinent articles. Scholars who are approaching a new topic may find a VSI especially useful, as will instructors who are preparing course syllabi. This article introduces the Constructing Sexualities VSI.
- Full Text:
- Date Issued: 2015
- Authors: Marx, Jacqueline , Donaldson, Natalie
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142040 , vital:38044 , DOI: 10.1177/0959353515572704
- Description: How have sexualities been dealt with in articles published in Feminism and Psychology since the inception of the journal in 1991? The idea for this overview arose from our experience of designing a critical sexualities course for graduate students in psychology. The articles featured in this overview form part of a Virtual Special Issue that can be located on the Feminism and Psychology website. Virtual Special Issues (VSI) are collections of previously published articles, which have been compiled by guest editors who are experts in the field. VSIs provide readers with an overview of feminist thought about a topic or theme, as well as an easy way to locate pertinent articles. Scholars who are approaching a new topic may find a VSI especially useful, as will instructors who are preparing course syllabi. This article introduces the Constructing Sexualities VSI.
- Full Text:
- Date Issued: 2015
Contrasting signals of genetic diversity and historical demography between two recently diverged marine and estuarine fish species
- von Der Heyden, Sophie, Toms, Jessica A, Teske, Peter R, Lamberth, Stephen J, Holleman, Wouter
- Authors: von Der Heyden, Sophie , Toms, Jessica A , Teske, Peter R , Lamberth, Stephen J , Holleman, Wouter
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445611 , vital:74407 , https://doi.org/10.3354/meps11191
- Description: Estuaries, at the confluence of marine and freshwater systems, are mostly of geologically recent origin and as such make excellent models for understanding recent speciation events. Using molecular approaches, we compared genetic diversity and demographic histories in 2 closely related southern African klipfish species, the marine Clinus superciliosus and the estuarine C. spatulatus. Strong genetic differentiation was identified using both mtDNA control region and nDNA S7 sequencing, despite some haplotype sharing. Coalescent-based modelling suggests that species divergence occurred during the Late Pleistocene or, more likely, during the Early Holocene, when present-day estuaries formed. Analyses of population demography suggest that C. superciliosus has undergone historical population expansion, whereas C. spatulatus is characterized by a population decline, potentially driven by repeated cycles of population crashes linked to the opening and closing of estuarine systems. This is also reflected in values of genetic diversity, which are almost an order of magnitude lower in the estuarine than in the marine species. Given the unique evolutionary history of C. spatulatus, a species that is restricted to only 2 South African estuaries, we highlight the need for a better understanding of the processes that have shaped the evolution of estuarine populations. The identification of unique genetic lineages in estuaries can help to better guide conservation and management efforts for some of South Africa’s most fragile habitats.
- Full Text: false
- Date Issued: 2015
- Authors: von Der Heyden, Sophie , Toms, Jessica A , Teske, Peter R , Lamberth, Stephen J , Holleman, Wouter
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445611 , vital:74407 , https://doi.org/10.3354/meps11191
- Description: Estuaries, at the confluence of marine and freshwater systems, are mostly of geologically recent origin and as such make excellent models for understanding recent speciation events. Using molecular approaches, we compared genetic diversity and demographic histories in 2 closely related southern African klipfish species, the marine Clinus superciliosus and the estuarine C. spatulatus. Strong genetic differentiation was identified using both mtDNA control region and nDNA S7 sequencing, despite some haplotype sharing. Coalescent-based modelling suggests that species divergence occurred during the Late Pleistocene or, more likely, during the Early Holocene, when present-day estuaries formed. Analyses of population demography suggest that C. superciliosus has undergone historical population expansion, whereas C. spatulatus is characterized by a population decline, potentially driven by repeated cycles of population crashes linked to the opening and closing of estuarine systems. This is also reflected in values of genetic diversity, which are almost an order of magnitude lower in the estuarine than in the marine species. Given the unique evolutionary history of C. spatulatus, a species that is restricted to only 2 South African estuaries, we highlight the need for a better understanding of the processes that have shaped the evolution of estuarine populations. The identification of unique genetic lineages in estuaries can help to better guide conservation and management efforts for some of South Africa’s most fragile habitats.
- Full Text: false
- Date Issued: 2015
Contributions to the study of a class of optimal control problems on the orthogonal groups SO(3) and SO(4)
- Authors: Adams, Ross Montague
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64826 , vital:28608
- Description: In this thesis we investigate a class of invariant optimal control problems, and their associated quadratic Hamilton-Poisson systems, on the orthogonal groups SO(3) and SO(4). Specifically, we are concerned with the class of left-invariant control affine systems. We begin by classifying all cost-extended systems on SO(3) under cost equivalence. (Cost-extended systems are closely related to optimal control problems.) A classification of all quadratic Hamilton-Poisson systems on the (minus) Lie-Poisson space so(3)*, under affine equivalence, is also obtained. For the normal forms obtained in our classification (of Hamilton-Poisson systems) we investigate the (Lyapunov) stability nature of the equilibria using spectral and energy-Casimir methods. For a subclass of these systems, we obtain analytic expressions for the integral curves of the associated Hamiltonian vector fields in terms of (basic) Jacobi elliptic functions. The explicit relationship between the classification of cost-extended systems on SO(3) and the classification of quadratic Hamilton- Poisson systems on so(3)* is provided. On SO(4), a classification of all left-invariant control affine systems under L-equivalence is obtained. We then determine which of these representatives are controllable, thus obtaining a classification under detached feedback equivalence. We also obtain a partial classification of quadratic Hamilton-Poisson systems on the Lie-Poisson space so(4)*. An investigation of the stability nature of the equilibria for a subclass of these systems is also done. Several illustrative examples of optimal control problems on the orthogonal group SO(3) are provided. More specifically, we consider an optimal control problem corresponding to a representative of our classification (of cost-extended system) for each possible number of control inputs. For each of these problems, we obtain explicit expressions for the extremal trajectories on the homogeneous space S2 by projecting the extremal trajectories on the group SO(3). The examples provided show how our classifications of cost-extended systems and Hamilton-Poisson systems can be used to obtain the optimal controls and the extremal trajectories corresponding to a large class of optimal control problems on SO(3). An example of a four-input optimal control problem on SO(4) is also provided. This example is provided to show how the solutions of certain problems on SO(4) can be related to the solutions of certain optimal control problems on SO(3).
- Full Text:
- Date Issued: 2015
- Authors: Adams, Ross Montague
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64826 , vital:28608
- Description: In this thesis we investigate a class of invariant optimal control problems, and their associated quadratic Hamilton-Poisson systems, on the orthogonal groups SO(3) and SO(4). Specifically, we are concerned with the class of left-invariant control affine systems. We begin by classifying all cost-extended systems on SO(3) under cost equivalence. (Cost-extended systems are closely related to optimal control problems.) A classification of all quadratic Hamilton-Poisson systems on the (minus) Lie-Poisson space so(3)*, under affine equivalence, is also obtained. For the normal forms obtained in our classification (of Hamilton-Poisson systems) we investigate the (Lyapunov) stability nature of the equilibria using spectral and energy-Casimir methods. For a subclass of these systems, we obtain analytic expressions for the integral curves of the associated Hamiltonian vector fields in terms of (basic) Jacobi elliptic functions. The explicit relationship between the classification of cost-extended systems on SO(3) and the classification of quadratic Hamilton- Poisson systems on so(3)* is provided. On SO(4), a classification of all left-invariant control affine systems under L-equivalence is obtained. We then determine which of these representatives are controllable, thus obtaining a classification under detached feedback equivalence. We also obtain a partial classification of quadratic Hamilton-Poisson systems on the Lie-Poisson space so(4)*. An investigation of the stability nature of the equilibria for a subclass of these systems is also done. Several illustrative examples of optimal control problems on the orthogonal group SO(3) are provided. More specifically, we consider an optimal control problem corresponding to a representative of our classification (of cost-extended system) for each possible number of control inputs. For each of these problems, we obtain explicit expressions for the extremal trajectories on the homogeneous space S2 by projecting the extremal trajectories on the group SO(3). The examples provided show how our classifications of cost-extended systems and Hamilton-Poisson systems can be used to obtain the optimal controls and the extremal trajectories corresponding to a large class of optimal control problems on SO(3). An example of a four-input optimal control problem on SO(4) is also provided. This example is provided to show how the solutions of certain problems on SO(4) can be related to the solutions of certain optimal control problems on SO(3).
- Full Text:
- Date Issued: 2015
Counsellors’ constructions of intimate partner violence (IPV) during pregnancy and their interventions with women suffering such IPV:
- Fleischack, Anne, Macleod, Catriona I, Böhmke, Werner
- Authors: Fleischack, Anne , Macleod, Catriona I , Böhmke, Werner
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143716 , vital:38276 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: South African research reveals a high prevalence of intimate partner violence (IPV) yet little research exists regarding IPV during pregnancy. In this paper we present data collected through narrative interviews with eight counsellors from two NGOs working with women experiencing IPV during pregnancy. Using a narrative-discursive analytical lens, attention was given to the construction of subject positions and power relations between the men and women in the counsellors’ narratives. Men were largely positioned as subscribing to violent patriarchal behaviour whilst women were mostly positioned as nurturing, and as victims. The counsellors saw IPV during pregnancy as occurring for a variety of reasons, including conflicts around abortion, and male partners finding the women physically unattractive. It was noted that IPV during pregnancy is managed by women in complex ways. Counsellors’ emphasis on individual counselling and leaving the IPV relationship suggests that women are ultimately responsible for their own wellbeing and success.
- Full Text:
- Date Issued: 2015
- Authors: Fleischack, Anne , Macleod, Catriona I , Böhmke, Werner
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143716 , vital:38276 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: South African research reveals a high prevalence of intimate partner violence (IPV) yet little research exists regarding IPV during pregnancy. In this paper we present data collected through narrative interviews with eight counsellors from two NGOs working with women experiencing IPV during pregnancy. Using a narrative-discursive analytical lens, attention was given to the construction of subject positions and power relations between the men and women in the counsellors’ narratives. Men were largely positioned as subscribing to violent patriarchal behaviour whilst women were mostly positioned as nurturing, and as victims. The counsellors saw IPV during pregnancy as occurring for a variety of reasons, including conflicts around abortion, and male partners finding the women physically unattractive. It was noted that IPV during pregnancy is managed by women in complex ways. Counsellors’ emphasis on individual counselling and leaving the IPV relationship suggests that women are ultimately responsible for their own wellbeing and success.
- Full Text:
- Date Issued: 2015
Critical realism, environmental learning and social-ecological change
- Price, Leigh, Lotz-Sisitka, Heila
- Authors: Price, Leigh , Lotz-Sisitka, Heila
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/436952 , vital:73319 , ISBN 9781315660899 , https://www.routledge.com/Critical-Realism-Environmental-Learning-and-Social-Ecological-Change/Price-Lotz-Sistka/p/book/9780367597689
- Description: The contemporary social-ecological condition is characterized by power-ful changes in the way that we relate to each other and to the environ-ment. This has led to increased ecological vulnerability, which is also ac-companied by ongoing, and increased societal vulnerability. Nevertheless there remain opportunities for developing new social-ecological rela-tions, and for social-ecological learning and change. This would seem to require a strong project of recovering ontology, and a challenging and broadening of dominant ways of knowing (Mignolo, 2000) that also tend to commit what Bhaskar describes as the ‘epistemic fallacy’, or the ‘the analysis or reduction of being to knowledge of being’ (Bhaskar, 2010, p. 1). In response, Bhaskar (ibid.) suggests critical realism as an alternative that embodies a ‘compatibility of ontological realism, epistemological relativism and judgmental rationality’. This includes a ‘re-vindication of ontology’ and the possibility of recognizing and accounting for structure, difference and change in the world in ways that escape ontological actu-alism and ontological monovalence or ‘the generation of a purely positive account of reality’ (ibid., p. 15).
- Full Text:
- Date Issued: 2015
- Authors: Price, Leigh , Lotz-Sisitka, Heila
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/436952 , vital:73319 , ISBN 9781315660899 , https://www.routledge.com/Critical-Realism-Environmental-Learning-and-Social-Ecological-Change/Price-Lotz-Sistka/p/book/9780367597689
- Description: The contemporary social-ecological condition is characterized by power-ful changes in the way that we relate to each other and to the environ-ment. This has led to increased ecological vulnerability, which is also ac-companied by ongoing, and increased societal vulnerability. Nevertheless there remain opportunities for developing new social-ecological rela-tions, and for social-ecological learning and change. This would seem to require a strong project of recovering ontology, and a challenging and broadening of dominant ways of knowing (Mignolo, 2000) that also tend to commit what Bhaskar describes as the ‘epistemic fallacy’, or the ‘the analysis or reduction of being to knowledge of being’ (Bhaskar, 2010, p. 1). In response, Bhaskar (ibid.) suggests critical realism as an alternative that embodies a ‘compatibility of ontological realism, epistemological relativism and judgmental rationality’. This includes a ‘re-vindication of ontology’ and the possibility of recognizing and accounting for structure, difference and change in the world in ways that escape ontological actu-alism and ontological monovalence or ‘the generation of a purely positive account of reality’ (ibid., p. 15).
- Full Text:
- Date Issued: 2015