Performance Effects of Concurrent Virtual Machine Execution in VMware Workstation 6
- Barnett, Richard J, Irwin, Barry V W
- Authors: Barnett, Richard J , Irwin, Barry V W
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429966 , vital:72655 , https://doi.org/10.1007/978-90-481-3660-5_56
- Description: The recent trend toward virtualized computing both as a means of serv-er consolidation and as a powerful desktop computing tool has lead into a wide variety of studies into the performance of hypervisor products. This study has investigated the scalability of VMware Workstation 6 on the desktop platform. We present comparative performance results for the concurrent execution of a number of virtual machines. A through statistical analysis of the performance results highlights the perfor-mance trends of different numbers of concurrent virtual machines and concludes that VMware workstation can scale in certain contexts. We find that there are different performance benefits dependant on the ap-plication and that memory intensive applications perform less effective-ly than those applications which are IO intensive. We also find that run-ning concurrent virtual machines offers a significant performance de-crease, but that the drop thereafter is less significant.
- Full Text:
- Date Issued: 2009
- Authors: Barnett, Richard J , Irwin, Barry V W
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429966 , vital:72655 , https://doi.org/10.1007/978-90-481-3660-5_56
- Description: The recent trend toward virtualized computing both as a means of serv-er consolidation and as a powerful desktop computing tool has lead into a wide variety of studies into the performance of hypervisor products. This study has investigated the scalability of VMware Workstation 6 on the desktop platform. We present comparative performance results for the concurrent execution of a number of virtual machines. A through statistical analysis of the performance results highlights the perfor-mance trends of different numbers of concurrent virtual machines and concludes that VMware workstation can scale in certain contexts. We find that there are different performance benefits dependant on the ap-plication and that memory intensive applications perform less effective-ly than those applications which are IO intensive. We also find that run-ning concurrent virtual machines offers a significant performance de-crease, but that the drop thereafter is less significant.
- Full Text:
- Date Issued: 2009
Photophysical, photochemical and electrochemical properties of water soluble silicon, titanium and zinc phthalocyanines
- Masilela, Nkosiphile, Idowu, Mopelola, Nyokong, Tebello
- Authors: Masilela, Nkosiphile , Idowu, Mopelola , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/264496 , vital:53739 , xlink:href="https://doi.org/10.1016/j.jphotochem.2008.10.009"
- Description: The photophysical, and photochemical properties of titanium, silicon and zinc octacarboxy phthalocyanine (OTiOCPc, (OH)2SiOCPc and ZnOCPc) and their tetrasulfonated counterparts (OTiTSPc, (OH)2SiTSPc and ZnTSPc) in phosphate-buffer solution (PBS), pH 10 were studied. The tetrasulfonated derivatives were also studied in the presence of a surfactant, cremophore EL (CEL) due to their high aggregation tendency in aqueous solutions. Triplet quantum yields ranged from 0.20 to 0.48 for MOCPcs and 0.32–0.65 for MTSPcs in the presence of CEL and in pH 10. High triplet lifetimes were observed for ZnTSPc (270 μs, in the presence of CEL) or ZnOCPc (130 μs) compared to values ranging from 50 to 70 μs for the rest of the complexes.
- Full Text:
- Date Issued: 2009
- Authors: Masilela, Nkosiphile , Idowu, Mopelola , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/264496 , vital:53739 , xlink:href="https://doi.org/10.1016/j.jphotochem.2008.10.009"
- Description: The photophysical, and photochemical properties of titanium, silicon and zinc octacarboxy phthalocyanine (OTiOCPc, (OH)2SiOCPc and ZnOCPc) and their tetrasulfonated counterparts (OTiTSPc, (OH)2SiTSPc and ZnTSPc) in phosphate-buffer solution (PBS), pH 10 were studied. The tetrasulfonated derivatives were also studied in the presence of a surfactant, cremophore EL (CEL) due to their high aggregation tendency in aqueous solutions. Triplet quantum yields ranged from 0.20 to 0.48 for MOCPcs and 0.32–0.65 for MTSPcs in the presence of CEL and in pH 10. High triplet lifetimes were observed for ZnTSPc (270 μs, in the presence of CEL) or ZnOCPc (130 μs) compared to values ranging from 50 to 70 μs for the rest of the complexes.
- Full Text:
- Date Issued: 2009
Photophysicochemical and fluorescence quenching studies of tetra-and octa-carboxy substituted silicon and germanium phthalocyanines
- Idowu, Mopelola, Nyokong, Tebello
- Authors: Idowu, Mopelola , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263500 , vital:53633 , xlink:href="https://doi.org/10.1016/j.jphotochem.2009.02.002"
- Description: Spectral, photophysical and photochemical properties of tetra- and octa-carboxy substituted metallophthalocyanines containing silicon and germanium as central metals ((OH)2GeTCPc, (OH)2SiTCPc, (OH)2GeOCPc and (OH)2SiOCPc) have been studied in dimethylsulfoxide (DMSO) and the trends in triplet, fluorescence, singlet oxygen quantum yields and triplet lifetimes are described for these compounds. The GePc derivatives exhibited high triplet quantum yields (ΦT = 0.79 for (OH)2GeOCPc and 0.82 for (OH)2GeTCPc compared to ΦT = 0.66 for (OH)2SiTCPc and 0.48 for (OH)2SiOCPc) due to the spin–orbit coupling induced by Ge(IV). The triplet lifetimes were higher for MOCPc (τT = 760 μs for (OH)2SiOCPc and 480 μs for (OH)2GeOCPc compared to τT = 210 μs for (OH)2SiTCPc and 260 μs for (OH)2GeTCPc). The fluorescent states of the metallophthalocyanine (MPc) complexes were effectively quenched by benzoquinone (BQ) and the quenching course was found to follow a diffusion-controlled (dynamic) bimolecular mechanism. Theoretical values of bimolecular rate constant for the interaction of the complexes with BQ were determined using the Stokes–Einstein–Smoluchowski model, and values together with the Stern–Volmer quenching constants were used in calculating the fluorescence lifetimes of the complexes.
- Full Text:
- Date Issued: 2009
- Authors: Idowu, Mopelola , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263500 , vital:53633 , xlink:href="https://doi.org/10.1016/j.jphotochem.2009.02.002"
- Description: Spectral, photophysical and photochemical properties of tetra- and octa-carboxy substituted metallophthalocyanines containing silicon and germanium as central metals ((OH)2GeTCPc, (OH)2SiTCPc, (OH)2GeOCPc and (OH)2SiOCPc) have been studied in dimethylsulfoxide (DMSO) and the trends in triplet, fluorescence, singlet oxygen quantum yields and triplet lifetimes are described for these compounds. The GePc derivatives exhibited high triplet quantum yields (ΦT = 0.79 for (OH)2GeOCPc and 0.82 for (OH)2GeTCPc compared to ΦT = 0.66 for (OH)2SiTCPc and 0.48 for (OH)2SiOCPc) due to the spin–orbit coupling induced by Ge(IV). The triplet lifetimes were higher for MOCPc (τT = 760 μs for (OH)2SiOCPc and 480 μs for (OH)2GeOCPc compared to τT = 210 μs for (OH)2SiTCPc and 260 μs for (OH)2GeTCPc). The fluorescent states of the metallophthalocyanine (MPc) complexes were effectively quenched by benzoquinone (BQ) and the quenching course was found to follow a diffusion-controlled (dynamic) bimolecular mechanism. Theoretical values of bimolecular rate constant for the interaction of the complexes with BQ were determined using the Stokes–Einstein–Smoluchowski model, and values together with the Stern–Volmer quenching constants were used in calculating the fluorescence lifetimes of the complexes.
- Full Text:
- Date Issued: 2009
Putting the ‘T’ into South African human rights: transsexuality in the post-apartheid order
- Vincent, Louise, Camminga, Bianca
- Authors: Vincent, Louise , Camminga, Bianca
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141606 , vital:37989 , DOI: 10.1177/1363460709346108
- Description: Informed by narratives provided by self-identified South African transsexuals, whose lives span different periods of South Africa’s political and social history, this article seeks to explore how South Africa’s medical, legal and military establishments have exerted power over the transsexual body. A variety of studies outline the extent to which the apartheid state was a highly gendered state characterized by inflexible patriarchal norms and the dominance of violent and authoritarian forms of masculine expression. Hyper masculinization and militarization were explicit goals of the apartheid state. Deviance from the state’s prescribed gender norms was not simply socially unacceptable, it was, in many cases, punishable. South Africa’s post-1994 democratic Constitution, in contrast, explicitly outlaws discrimination on the basis of sexual orientation. But the democratic legal framework, which provides significant protections for freedom of sexual expression and freedom from discrimination for homosexuals has arguably had less of an impact on the lives of South Africa’s transsexual community. The state, even the post-apartheid state, has been loathe to move beyond the idea of a necessary correlation between the physical make-up of the body and the gender identity of a person in the way in which it has treated the idea of transsexualism.
- Full Text:
- Date Issued: 2009
- Authors: Vincent, Louise , Camminga, Bianca
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141606 , vital:37989 , DOI: 10.1177/1363460709346108
- Description: Informed by narratives provided by self-identified South African transsexuals, whose lives span different periods of South Africa’s political and social history, this article seeks to explore how South Africa’s medical, legal and military establishments have exerted power over the transsexual body. A variety of studies outline the extent to which the apartheid state was a highly gendered state characterized by inflexible patriarchal norms and the dominance of violent and authoritarian forms of masculine expression. Hyper masculinization and militarization were explicit goals of the apartheid state. Deviance from the state’s prescribed gender norms was not simply socially unacceptable, it was, in many cases, punishable. South Africa’s post-1994 democratic Constitution, in contrast, explicitly outlaws discrimination on the basis of sexual orientation. But the democratic legal framework, which provides significant protections for freedom of sexual expression and freedom from discrimination for homosexuals has arguably had less of an impact on the lives of South Africa’s transsexual community. The state, even the post-apartheid state, has been loathe to move beyond the idea of a necessary correlation between the physical make-up of the body and the gender identity of a person in the way in which it has treated the idea of transsexualism.
- Full Text:
- Date Issued: 2009
Rapid biological assessment of the fishery potential of Xonxa Dam, near Queenstown, South Africa
- Richardson, T J, Booth, Anthony J, Weyl, Olaf L F
- Authors: Richardson, T J , Booth, Anthony J , Weyl, Olaf L F
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125798 , vital:35818 , https://doi.10.2989/AJAS.2009.34.1.9.734
- Description: In Africa, the harvesting of fish from small reservoirs has been identified as an important food resource for small rural communities, particularly those living close to waterbodies (Kapetsky and Petr 1984, Marshall and Maes 1994, van der Knaap 1994). Development of fisheries to utilize these resources has recently been identified by the African Union as a priority investment area for poverty alleviation and regional economic development (NEPAD 2005). Within a South African context, it is suspected that there will be increased interest in developing these fisheries to address major national policy objectives, which include food security, economic empowerment, optimal economic benefit from water, and poverty eradication (RSA 1998a, 1998b). South Africa, however, presents a somewhat anomalous situation. The lack of a fishing history in communities, the lack of species with a high fisheries potential, inadequate inland fisheries policy and a lack of directed fisheries development have resulted in low utilisation levels of fish resources in South African reservoirs (Weyl et al. 2007).
- Full Text:
- Date Issued: 2009
- Authors: Richardson, T J , Booth, Anthony J , Weyl, Olaf L F
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125798 , vital:35818 , https://doi.10.2989/AJAS.2009.34.1.9.734
- Description: In Africa, the harvesting of fish from small reservoirs has been identified as an important food resource for small rural communities, particularly those living close to waterbodies (Kapetsky and Petr 1984, Marshall and Maes 1994, van der Knaap 1994). Development of fisheries to utilize these resources has recently been identified by the African Union as a priority investment area for poverty alleviation and regional economic development (NEPAD 2005). Within a South African context, it is suspected that there will be increased interest in developing these fisheries to address major national policy objectives, which include food security, economic empowerment, optimal economic benefit from water, and poverty eradication (RSA 1998a, 1998b). South Africa, however, presents a somewhat anomalous situation. The lack of a fishing history in communities, the lack of species with a high fisheries potential, inadequate inland fisheries policy and a lack of directed fisheries development have resulted in low utilisation levels of fish resources in South African reservoirs (Weyl et al. 2007).
- Full Text:
- Date Issued: 2009
Reflections on the sine causa requirements and the condictiones in South African law
- Authors: Glover, Graham B
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70668 , vital:29687 , https://hdl.handle.net/10520/EJC54716
- Description: The condictiones present interesting and difficult challenges of classification for the modern South African jurist. Their casuistic development has made them difficult to work with, and for a long time it was argued that a single general enrichment action should take their place. But the Supreme Court of Appeal in McCarthy Retail Ltd v Shortdistance Carriers CC 2001 3 SA 482 (SCA) chose not to follow this path, and instead preferred the idea that a general enrichment action should be subsidiary to the traditional actions. This has breathed new life into debates on the future of the condictiones. This article first examines the current range of application of the condictiones. It then proceeds to show how the courts in the first decade of the 21st century seem to have eschewed the technicalities inherent in pleading the condictiones, and have preferred rather to resolve cases by applying the general requirements of enrichment liability, in contrast to the injunction in McCarthy. The difficulty with this approach is the lack of substance that is given to the sine causa requirement. The article proceeds to examine the various theories about how we in South Africa should understand and give content to the sine causa requirement. This provides a springboard for considering the possible futures of the condictiones. Broadly, it seems that two options are possible: either to collapse the condictiones into one action to deal with cases of enrichment by transfer; or largely to retain the status quo. The most recent decisions of the Supreme Court of Appeal indicate that the latter, more conservative option is likely to be chosen in the short-term. If this approach is to be adopted, it will require a further review of how each of the constituent condictiones fulfils a particular function. A revisionist view of the condictio indebiti is postulated by way of example.
- Full Text: false
- Date Issued: 2009
- Authors: Glover, Graham B
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70668 , vital:29687 , https://hdl.handle.net/10520/EJC54716
- Description: The condictiones present interesting and difficult challenges of classification for the modern South African jurist. Their casuistic development has made them difficult to work with, and for a long time it was argued that a single general enrichment action should take their place. But the Supreme Court of Appeal in McCarthy Retail Ltd v Shortdistance Carriers CC 2001 3 SA 482 (SCA) chose not to follow this path, and instead preferred the idea that a general enrichment action should be subsidiary to the traditional actions. This has breathed new life into debates on the future of the condictiones. This article first examines the current range of application of the condictiones. It then proceeds to show how the courts in the first decade of the 21st century seem to have eschewed the technicalities inherent in pleading the condictiones, and have preferred rather to resolve cases by applying the general requirements of enrichment liability, in contrast to the injunction in McCarthy. The difficulty with this approach is the lack of substance that is given to the sine causa requirement. The article proceeds to examine the various theories about how we in South Africa should understand and give content to the sine causa requirement. This provides a springboard for considering the possible futures of the condictiones. Broadly, it seems that two options are possible: either to collapse the condictiones into one action to deal with cases of enrichment by transfer; or largely to retain the status quo. The most recent decisions of the Supreme Court of Appeal indicate that the latter, more conservative option is likely to be chosen in the short-term. If this approach is to be adopted, it will require a further review of how each of the constituent condictiones fulfils a particular function. A revisionist view of the condictio indebiti is postulated by way of example.
- Full Text: false
- Date Issued: 2009
Reform in defence of sovereignty: South Africa in the UN Security Council, 2007–2008
- Authors: Bischoff, Paul, 1954-
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161431 , vital:40626 , https://0-doi.org.wam.seals.ac.za/10.1177/000203970904400205
- Description: After 1994, South Africa became the sine qua non of an internationalist state, willing to promote cooperation amongst a plurality of actors, believing common interests to be more important than their differences. This raised the hopes of constitutionalists, and those who believed in the expansion of a liberal democratic peace. South Africa has acted out two seemingly contradictory roles: those of a reformer and those of a conserver. By 2007–2008 she had shifted towards the latter, conservative-reformist position. Thus, South Africa's voting record at the General Assembly expressed her overriding concern to regionalise African issues and minimise the US and the West shaping political events. This brought her foreign policy into sharper relief. But while in some sense successful, it came at a price: a controversy about her surrendering her internationalism and principles on human rights for African unity and traditional sovereignty. But it also marked the arrival of South Africa in the world of international Realpolitik.
- Full Text:
- Date Issued: 2009
- Authors: Bischoff, Paul, 1954-
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161431 , vital:40626 , https://0-doi.org.wam.seals.ac.za/10.1177/000203970904400205
- Description: After 1994, South Africa became the sine qua non of an internationalist state, willing to promote cooperation amongst a plurality of actors, believing common interests to be more important than their differences. This raised the hopes of constitutionalists, and those who believed in the expansion of a liberal democratic peace. South Africa has acted out two seemingly contradictory roles: those of a reformer and those of a conserver. By 2007–2008 she had shifted towards the latter, conservative-reformist position. Thus, South Africa's voting record at the General Assembly expressed her overriding concern to regionalise African issues and minimise the US and the West shaping political events. This brought her foreign policy into sharper relief. But while in some sense successful, it came at a price: a controversy about her surrendering her internationalism and principles on human rights for African unity and traditional sovereignty. But it also marked the arrival of South Africa in the world of international Realpolitik.
- Full Text:
- Date Issued: 2009
Reviews: Unsettling Questions: Palestine, Israel, the Holy Land and Zion
- Stähler, A, Vice, S, Brauner, D, Bassi, S, Naidu, Samantha, King, B, O'Neal, G S, Aldama, F L, Gibbs, J, Rotstein, J R U, Calderaro, M A
- Authors: Stähler, A , Vice, S , Brauner, D , Bassi, S , Naidu, Samantha , King, B , O'Neal, G S , Aldama, F L , Gibbs, J , Rotstein, J R U , Calderaro, M A
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157948 , vital:40133 , https://doi.org/10.1080/02690050802589479
- Description: Reviews: Unsettling Questions: Palestine, Israel, the Holy Land and Zion
- Full Text:
- Date Issued: 2009
- Authors: Stähler, A , Vice, S , Brauner, D , Bassi, S , Naidu, Samantha , King, B , O'Neal, G S , Aldama, F L , Gibbs, J , Rotstein, J R U , Calderaro, M A
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157948 , vital:40133 , https://doi.org/10.1080/02690050802589479
- Description: Reviews: Unsettling Questions: Palestine, Israel, the Holy Land and Zion
- Full Text:
- Date Issued: 2009
Rich Representation and Visualisation of Time-Series Data
- Kerr, Simon, Foster, Greg, Irwin, Barry V W
- Authors: Kerr, Simon , Foster, Greg , Irwin, Barry V W
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428130 , vital:72488 , https://www.researchgate.net/profile/Barry-Ir-win/publication/265821926_Rich_Representation_and_Visualisation_of_Time-Series_Data/links/5548a1350cf26a7bf4daefb1/Rich-Representation-and-Visualisation-of-Time-Series-Data.pdf
- Description: Currently the majority of data is visualized using static graphs and ta-bles. However, static graphs still leave much to be desired and provide only a small insight into trends and changes between values. We pro-pose a move away from purely static representations of data towards a more fluid and understandable environment for data representation. This is achieved through the use of an application which animates time based data. Animating time based data allows one to see nuances within a dataset from a more comprehensive perspective. This is espe-cially useful within the time based data rich telecommunications indus-try. The application comprises of two parts-the backend manages raw data which is then passed to the frontend for animation. A play function allows one to play through a time series. Which creates a fluid and dy-namic environment for exploring data. Both the advantages and disad-vantages of this approach are investigated and an application is intro-duced which can be used to animate and explore datasets.
- Full Text:
- Date Issued: 2009
- Authors: Kerr, Simon , Foster, Greg , Irwin, Barry V W
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428130 , vital:72488 , https://www.researchgate.net/profile/Barry-Ir-win/publication/265821926_Rich_Representation_and_Visualisation_of_Time-Series_Data/links/5548a1350cf26a7bf4daefb1/Rich-Representation-and-Visualisation-of-Time-Series-Data.pdf
- Description: Currently the majority of data is visualized using static graphs and ta-bles. However, static graphs still leave much to be desired and provide only a small insight into trends and changes between values. We pro-pose a move away from purely static representations of data towards a more fluid and understandable environment for data representation. This is achieved through the use of an application which animates time based data. Animating time based data allows one to see nuances within a dataset from a more comprehensive perspective. This is espe-cially useful within the time based data rich telecommunications indus-try. The application comprises of two parts-the backend manages raw data which is then passed to the frontend for animation. A play function allows one to play through a time series. Which creates a fluid and dy-namic environment for exploring data. Both the advantages and disad-vantages of this approach are investigated and an application is intro-duced which can be used to animate and explore datasets.
- Full Text:
- Date Issued: 2009
SDF-1 and PDGF enhance αvβ5-mediated ERK activation and adhesion-independent growth of human pre-B cell lines:
- Acharya, Mridu, Edkins, Adrienne L, Ozanne, B, Cushley, W
- Authors: Acharya, Mridu , Edkins, Adrienne L , Ozanne, B , Cushley, W
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165044 , vital:41204 , DOI: 10.1038/leu.2009.126
- Description: CD23 acts through the αvβ5 integrin to promote growth of human pre-B cell lines in an adhesion-independent manner. αvβ5 is expressed on normal B-cell precursors in the bone marrow. Soluble CD23 (sCD23), short CD23-derived peptides containing the arg-lys-cys (RKC) motif recognized by αvβ5 and anti-αvβ5 monoclonal antibodies (MAbs) all sustain growth of pre-B cell lines. The chemokine stromal cell-derived factor-1 (SDF-1) regulates key processes during B-cell development. SDF-1 enhanced the growth-sustaining effect driven by ligation of αvβ5 with anti-αvβ5 MAb 15F-11, sCD23 or CD23-derived RKC-containing peptides. This effect was restricted to B-cell precursors and was specific to SDF-1.
- Full Text:
- Date Issued: 2009
- Authors: Acharya, Mridu , Edkins, Adrienne L , Ozanne, B , Cushley, W
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165044 , vital:41204 , DOI: 10.1038/leu.2009.126
- Description: CD23 acts through the αvβ5 integrin to promote growth of human pre-B cell lines in an adhesion-independent manner. αvβ5 is expressed on normal B-cell precursors in the bone marrow. Soluble CD23 (sCD23), short CD23-derived peptides containing the arg-lys-cys (RKC) motif recognized by αvβ5 and anti-αvβ5 monoclonal antibodies (MAbs) all sustain growth of pre-B cell lines. The chemokine stromal cell-derived factor-1 (SDF-1) regulates key processes during B-cell development. SDF-1 enhanced the growth-sustaining effect driven by ligation of αvβ5 with anti-αvβ5 MAb 15F-11, sCD23 or CD23-derived RKC-containing peptides. This effect was restricted to B-cell precursors and was specific to SDF-1.
- Full Text:
- Date Issued: 2009
Sigtuna think piece 6: A case of exploring learning interactions in rural farming communities of practice in Manicaland, Zimbabwe
- Authors: Pesanayi, Tichaona V
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386427 , vital:68140 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122802"
- Description: Food insecurity is one of the major threats to sustainable development in Africa, and particularly southern Africa. Climate change is increasingly having negative impacts on food production, further increasing the vulnerability of resource-poor communities. This paper outlines a research study conducted in two Zimbabwean smallholder communities of practice, with the aim of understanding learning interactions taking place within the community of practice that influence its choice of cultivated food plants. This would hopefully inform capability-centred teaching and learning. The study was conducted in the context of vulnerability to environment risk, socio-political pressures and a market-oriented agro-based economy in recession. Various causal mechanisms influencing plant-food choice were identified using critical realist ontological analysis. These included mixed messages from external influences in conflict with local knowledge due to power knowledge relationships. A number of learning interactions were found to be important in promoting the adaptive capacity of the farmers to chronic drought, which included inter-generational knowledge sharing; farmer to farmer exchange and reflective dialogue; experiential learning; farmers ‘passing on’ part of their harvests to other farmers; farming communities learning from risk and responding to risk; and learning from trying things out. The implications for capability-centred social learning processes were that it is important to understand the causal mechanisms that influence choices; and to confront tensions, while reducing ambivalence. A focus on more sustainable alternatives, feasible and practical for farmers, was recommended. These findings, in the context of one case study, create research questions to be examined in other case contexts in environmental education research focusing on climate change learning and adaptation.
- Full Text:
- Date Issued: 2009
- Authors: Pesanayi, Tichaona V
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386427 , vital:68140 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122802"
- Description: Food insecurity is one of the major threats to sustainable development in Africa, and particularly southern Africa. Climate change is increasingly having negative impacts on food production, further increasing the vulnerability of resource-poor communities. This paper outlines a research study conducted in two Zimbabwean smallholder communities of practice, with the aim of understanding learning interactions taking place within the community of practice that influence its choice of cultivated food plants. This would hopefully inform capability-centred teaching and learning. The study was conducted in the context of vulnerability to environment risk, socio-political pressures and a market-oriented agro-based economy in recession. Various causal mechanisms influencing plant-food choice were identified using critical realist ontological analysis. These included mixed messages from external influences in conflict with local knowledge due to power knowledge relationships. A number of learning interactions were found to be important in promoting the adaptive capacity of the farmers to chronic drought, which included inter-generational knowledge sharing; farmer to farmer exchange and reflective dialogue; experiential learning; farmers ‘passing on’ part of their harvests to other farmers; farming communities learning from risk and responding to risk; and learning from trying things out. The implications for capability-centred social learning processes were that it is important to understand the causal mechanisms that influence choices; and to confront tensions, while reducing ambivalence. A focus on more sustainable alternatives, feasible and practical for farmers, was recommended. These findings, in the context of one case study, create research questions to be examined in other case contexts in environmental education research focusing on climate change learning and adaptation.
- Full Text:
- Date Issued: 2009
Sigtuna Think Piece 8: Piecing together conceptual framings for climate change education research in southern African contexts
- Authors: Lotz-Sisitka, Heila
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67378 , vital:29082 , https://www.ajol.info/index.php/sajee/article/view/122808
- Description: publisher version , This think piece considers a range of theoretical and conceptual tools that may assist with the emergence of a research agenda for climate change in education. It considers the conditions that are created by climate change in and for southern African contexts, and then deliberates which contextually related theoretical tools may be useful to frame research questions for climate change education. I consider the educational research implications of adaptation practices, reflexive justice and agency, reflexivity and capability, noting that a climate change education research agenda, not different to a wider reflexive environmental education research agenda dealing with transformative praxis in southern Africa, is essentially a sociologically and historically emergent ‘researching with’ agenda, and is in effect a social learning process. In putting together these conceptual framings for a climate change research agenda in southern Africa, I am interested in exploring how participatory social learning research may strengthen agency and reflexivity (development of capabilities) in response to socio-ecological conditions.
- Full Text:
- Date Issued: 2009
- Authors: Lotz-Sisitka, Heila
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67378 , vital:29082 , https://www.ajol.info/index.php/sajee/article/view/122808
- Description: publisher version , This think piece considers a range of theoretical and conceptual tools that may assist with the emergence of a research agenda for climate change in education. It considers the conditions that are created by climate change in and for southern African contexts, and then deliberates which contextually related theoretical tools may be useful to frame research questions for climate change education. I consider the educational research implications of adaptation practices, reflexive justice and agency, reflexivity and capability, noting that a climate change education research agenda, not different to a wider reflexive environmental education research agenda dealing with transformative praxis in southern Africa, is essentially a sociologically and historically emergent ‘researching with’ agenda, and is in effect a social learning process. In putting together these conceptual framings for a climate change research agenda in southern Africa, I am interested in exploring how participatory social learning research may strengthen agency and reflexivity (development of capabilities) in response to socio-ecological conditions.
- Full Text:
- Date Issued: 2009
Simulating crowd phenomena in african markets
- Tasse, Flora P, Glass, Kevin R, Bangay, Shaun D
- Authors: Tasse, Flora P , Glass, Kevin R , Bangay, Shaun D
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433285 , vital:72959 , https://doi.org/10.1145/1503454.1503463
- Description: Crowd simulation is an important feature in the computer graphics field. Typical implementations simulate battle scenes, emergency situations, safety issues or add content to virtual environments. The problem stated in this paper falls in the last category. We present a crowd simulation behavioural model which allows us to simulate identified phenomena in popular local African markets such as narrow street flows and crowd formation around street performances. We propose a three-tier architecture model enable to produce intentions, perform path planning and control movement. We demonstrate that this approach produces the desired behaviour associated with crowds in an African market, which includes navigation, flow formation and circle creation.
- Full Text:
- Date Issued: 2009
- Authors: Tasse, Flora P , Glass, Kevin R , Bangay, Shaun D
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433285 , vital:72959 , https://doi.org/10.1145/1503454.1503463
- Description: Crowd simulation is an important feature in the computer graphics field. Typical implementations simulate battle scenes, emergency situations, safety issues or add content to virtual environments. The problem stated in this paper falls in the last category. We present a crowd simulation behavioural model which allows us to simulate identified phenomena in popular local African markets such as narrow street flows and crowd formation around street performances. We propose a three-tier architecture model enable to produce intentions, perform path planning and control movement. We demonstrate that this approach produces the desired behaviour associated with crowds in an African market, which includes navigation, flow formation and circle creation.
- Full Text:
- Date Issued: 2009
Solvent and central metal effects on the photophysical and photochemical properties of peripherally tetra mercaptopyridine substituted metallophthalocyanines
- Moeno, Sharon, Nyokong, Tebello
- Authors: Moeno, Sharon , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263522 , vital:53635 , xlink:href="https://doi.org/10.1016/j.jphotochem.2009.01.021"
- Description: The synthesis of peripherally tetra 2-mercaptopyridine substituted phthalocyanines containing Si, Ga, Sn and In as central metal ions is reported for the first time in this study. Photophysical and photochemical studies were carried out on these compounds in order to determine the potential of the complexes as photosensitizers for use in photodynamic therapy. Fluorescence quantum yields (ΦF) ranged from 0.012 to 0.2 and triplet quantum yields (ΦT) from 0.54 to 0.89 in dimethylformamide (DMF) and from 0.65 to 0.93 in dimethylsulfoxide (DMSO). The triplet lifetimes ranged from 20 to 130 μs, the low values are due to the heavy atom effects of the central metal. The triplet lifetimes were larger in DMSO when compared with DMF.
- Full Text:
- Date Issued: 2009
- Authors: Moeno, Sharon , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263522 , vital:53635 , xlink:href="https://doi.org/10.1016/j.jphotochem.2009.01.021"
- Description: The synthesis of peripherally tetra 2-mercaptopyridine substituted phthalocyanines containing Si, Ga, Sn and In as central metal ions is reported for the first time in this study. Photophysical and photochemical studies were carried out on these compounds in order to determine the potential of the complexes as photosensitizers for use in photodynamic therapy. Fluorescence quantum yields (ΦF) ranged from 0.012 to 0.2 and triplet quantum yields (ΦT) from 0.54 to 0.89 in dimethylformamide (DMF) and from 0.65 to 0.93 in dimethylsulfoxide (DMSO). The triplet lifetimes ranged from 20 to 130 μs, the low values are due to the heavy atom effects of the central metal. The triplet lifetimes were larger in DMSO when compared with DMF.
- Full Text:
- Date Issued: 2009
Some (more) features of conversation amongst women friends:
- Authors: Hunt, Sally
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/139149 , vital:37709 , DOI: 10.2989/16073610509486400
- Description: This paper provides an analysis of a conversation between young women friends, which is analysed in terms of Coates’ (1988; 1997; 1999) work on the features of conversation amongst female friends. Coates identifies a number of features which, she says, are typical of conversation between (adult) female friends: a domestic setting, female participants, topics relating to people and feelings, and various formal features including smooth topic development, frequent minimal responses, supportive forms of simultaneous speech and epistemic modality (‘softening’ strategies, including tag questions) (Coates, 1988: 97). The overarching function, she claims, is one of solidarity-building and support: ‘the maintenance of good social relationships’ and ‘the reaffirming and strengthening of friendship’ (Coates, 1988: 98). While this last feature, the function of conversation between women friends, is borne out by the extract to be analysed, the participants in my study utilise different strategies to accomplish it and, in several respects, do not utilise the other features Coates claims to be typical. The research shows, through a detailed analysis of a nineminute extract from a conversation between three women friends, that the features assumed by Coates to be central conversational strategies in the building of female friendship are not the only ways for women to accomplish this function.
- Full Text:
- Date Issued: 2009
- Authors: Hunt, Sally
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/139149 , vital:37709 , DOI: 10.2989/16073610509486400
- Description: This paper provides an analysis of a conversation between young women friends, which is analysed in terms of Coates’ (1988; 1997; 1999) work on the features of conversation amongst female friends. Coates identifies a number of features which, she says, are typical of conversation between (adult) female friends: a domestic setting, female participants, topics relating to people and feelings, and various formal features including smooth topic development, frequent minimal responses, supportive forms of simultaneous speech and epistemic modality (‘softening’ strategies, including tag questions) (Coates, 1988: 97). The overarching function, she claims, is one of solidarity-building and support: ‘the maintenance of good social relationships’ and ‘the reaffirming and strengthening of friendship’ (Coates, 1988: 98). While this last feature, the function of conversation between women friends, is borne out by the extract to be analysed, the participants in my study utilise different strategies to accomplish it and, in several respects, do not utilise the other features Coates claims to be typical. The research shows, through a detailed analysis of a nineminute extract from a conversation between three women friends, that the features assumed by Coates to be central conversational strategies in the building of female friendship are not the only ways for women to accomplish this function.
- Full Text:
- Date Issued: 2009
St. Petersburg
- Authors: Krueger, Anton
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229818 , vital:49713 , xlink:href="https://hdl.handle.net/10520/EJC47812"
- Full Text:
- Date Issued: 2009
- Authors: Krueger, Anton
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229818 , vital:49713 , xlink:href="https://hdl.handle.net/10520/EJC47812"
- Full Text:
- Date Issued: 2009
Steps by steps: the making of the Steps for the Future documentary series, likka Vehkalathi and Don Edkins: book review
- Authors: Schoon, Alette
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159348 , vital:40290 , https://hdl.handle.net/10520/EJC139902
- Description: In a frank, offbeat memoir, Finnish filmmaker Iikka Vehkalahti and his South African partner Don Edkins, tell their story of how they developed an infectious concept, charmed big broadcasters - and nearly didn't get the films made. Alette Schoon gets taken along for the ride.
- Full Text:
- Date Issued: 2009
- Authors: Schoon, Alette
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159348 , vital:40290 , https://hdl.handle.net/10520/EJC139902
- Description: In a frank, offbeat memoir, Finnish filmmaker Iikka Vehkalahti and his South African partner Don Edkins, tell their story of how they developed an infectious concept, charmed big broadcasters - and nearly didn't get the films made. Alette Schoon gets taken along for the ride.
- Full Text:
- Date Issued: 2009
Students as Agents of Social Change-Student Initiatives at Rhodes University, South Africa
- Authors: Togo, Muchaiteyi
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386561 , vital:68151 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122830"
- Description: Rhodes University has a diversity of sustainable development initiatives meant for students and in a range of cases activities are initiated by students themselves with the support of the university. Results of a sustainability assessment revealed the involvement of students in environmental societies, environmental awareness campaigns, campus sustainability initiatives and community sustainability projects. Though most of the projects are still in their infancy and some challenges are yet to be overcome, the sustainability initiatives are gaining momentum and have contributed to improving the overall picture of sustainability at the university. Based on the results of the Rhodes University case study, the underpinning viewpoint in this paper is that university students are not merely recipients of Education for Sustainable Development but have the capacity to become agents for social change.
- Full Text:
- Date Issued: 2009
- Authors: Togo, Muchaiteyi
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386561 , vital:68151 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122830"
- Description: Rhodes University has a diversity of sustainable development initiatives meant for students and in a range of cases activities are initiated by students themselves with the support of the university. Results of a sustainability assessment revealed the involvement of students in environmental societies, environmental awareness campaigns, campus sustainability initiatives and community sustainability projects. Though most of the projects are still in their infancy and some challenges are yet to be overcome, the sustainability initiatives are gaining momentum and have contributed to improving the overall picture of sustainability at the university. Based on the results of the Rhodes University case study, the underpinning viewpoint in this paper is that university students are not merely recipients of Education for Sustainable Development but have the capacity to become agents for social change.
- Full Text:
- Date Issued: 2009
Study of the photophysical behavior of tetrasulfonated metallophthalocyanines in the presence of CdTe quantum dots
- Idowu, Mopelola, Nyokong, Tebello
- Authors: Idowu, Mopelola , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/264138 , vital:53701 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: Förster resonance energy transfer (FRET) studies were carried out with CdTe quantum dots (QDs) synthesized in aqueous phase and various tetrasulfonated metallophthalocyanines (MPcS4, M = aluminum ((OH)AlPcS4), zinc (ZnPcS4), silicon ((OH)2SiPcS4) and germanium ((OH)2GePcS4) in a H2O:MeOH (1:1) solvent mixture. The QDs studied were capped with thioglycolic acid (TGA) or mercaptopropionic acid (MPA) with sizes ranging from 2.3 to 3.7 nm. Non-radiative energy transfer from QDs emission to MPcS4 complexes was observed. Study of the photophysics of the MPcs in the presence of the QDs revealed high triplet state quantum yields (ΦT, ranging from 0.41 to 0.85 in the presence of QDs), with corresponding long triplet state lifetimes (τT, which ranged from 140 to 610 μs in the presence of QDs) to allow for photosensitized reactions to occur. The efficiency of energy transfer and the donor–acceptor distance between the MPcs and the QDs were also evaluated.
- Full Text:
- Date Issued: 2009
- Authors: Idowu, Mopelola , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/264138 , vital:53701 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: Förster resonance energy transfer (FRET) studies were carried out with CdTe quantum dots (QDs) synthesized in aqueous phase and various tetrasulfonated metallophthalocyanines (MPcS4, M = aluminum ((OH)AlPcS4), zinc (ZnPcS4), silicon ((OH)2SiPcS4) and germanium ((OH)2GePcS4) in a H2O:MeOH (1:1) solvent mixture. The QDs studied were capped with thioglycolic acid (TGA) or mercaptopropionic acid (MPA) with sizes ranging from 2.3 to 3.7 nm. Non-radiative energy transfer from QDs emission to MPcS4 complexes was observed. Study of the photophysics of the MPcs in the presence of the QDs revealed high triplet state quantum yields (ΦT, ranging from 0.41 to 0.85 in the presence of QDs), with corresponding long triplet state lifetimes (τT, which ranged from 140 to 610 μs in the presence of QDs) to allow for photosensitized reactions to occur. The efficiency of energy transfer and the donor–acceptor distance between the MPcs and the QDs were also evaluated.
- Full Text:
- Date Issued: 2009
Synthesis and characterization of electrocatalytic conjugates of tetraamino cobalt (II) phthalocyanine and single wall carbon nanotubes
- Mugadza, Tawanda, Nyokong, Tebello
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263341 , vital:53619 , xlink:href="https://doi.org/10.1016/j.electacta.2009.05.074"
- Description: In this paper we report on the synthesis and characterization of electrocatalytic conjugates of tetraamino cobalt (II) phthalocyanine and single walled carbon nanotubes (CoTAPc–SWCNT-linked) for use as electrode surface modifiers. FTIR, UV–vis and Raman spectroscopies were used to ascertain the chemical linkage between CoTAPc and SWCNT while cyclic voltammetry and rotating disk electrode voltammetry were used to assess the electrocatalytic efficiency of the linked product towards the oxidation of 2-mercaptoethanol. The CoTAPc–SWCNT-linked-GCE demonstrated very good catalytic efficiency relative to CoTAPc–SWCNT-mixed-GCE, CoTAPc-GCE and f-SWCNTs-GCE (functionalised SWCNT). CoTAPc–SWCNT-linked-GCE gave a sensitivity of 0.2 μA/μM and a limit of detection (LOD) of 1.2 × 10−7 M for 2-mercaptoethanol (2-ME) at pH 4.
- Full Text:
- Date Issued: 2009
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263341 , vital:53619 , xlink:href="https://doi.org/10.1016/j.electacta.2009.05.074"
- Description: In this paper we report on the synthesis and characterization of electrocatalytic conjugates of tetraamino cobalt (II) phthalocyanine and single walled carbon nanotubes (CoTAPc–SWCNT-linked) for use as electrode surface modifiers. FTIR, UV–vis and Raman spectroscopies were used to ascertain the chemical linkage between CoTAPc and SWCNT while cyclic voltammetry and rotating disk electrode voltammetry were used to assess the electrocatalytic efficiency of the linked product towards the oxidation of 2-mercaptoethanol. The CoTAPc–SWCNT-linked-GCE demonstrated very good catalytic efficiency relative to CoTAPc–SWCNT-mixed-GCE, CoTAPc-GCE and f-SWCNTs-GCE (functionalised SWCNT). CoTAPc–SWCNT-linked-GCE gave a sensitivity of 0.2 μA/μM and a limit of detection (LOD) of 1.2 × 10−7 M for 2-mercaptoethanol (2-ME) at pH 4.
- Full Text:
- Date Issued: 2009