Self-assembled monolayers (SAMs) of cobalt tetracarboxylic acidchloride phthalocyanine covalently attached onto a preformed mercaptoethanol SAM
- Mashazi, Philani N, Ozoemena, Kenneth I, Maree, David M, Nyokong, Tebello
- Authors: Mashazi, Philani N , Ozoemena, Kenneth I , Maree, David M , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283792 , vital:55989 , xlink:href="https://doi.org/10.1016/j.electacta.2005.10.004"
- Description: A feasible method of fabricating phthalocyanine sensor was developed by covalent attachment of cobalt tetracarboxylic acidchloride phthalocyanine (CoTCACIPc) onto a preformed 2-mercaptoethanol (2-ME) self-assembled monolayer (SAM) modified gold electrode (designated as CoTCACIPc-2-ME-SAM). The surface concentration of the CoTCACIPc was found to be 4.58 × 10−10 mol/cm2. The sensor gave a linear response to L-cysteine over the concentration range 0.28–20 μM with a detection limit of 5 × 10−7 M and best response time of 2 s.
- Full Text:
- Date Issued: 2006
- Authors: Mashazi, Philani N , Ozoemena, Kenneth I , Maree, David M , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283792 , vital:55989 , xlink:href="https://doi.org/10.1016/j.electacta.2005.10.004"
- Description: A feasible method of fabricating phthalocyanine sensor was developed by covalent attachment of cobalt tetracarboxylic acidchloride phthalocyanine (CoTCACIPc) onto a preformed 2-mercaptoethanol (2-ME) self-assembled monolayer (SAM) modified gold electrode (designated as CoTCACIPc-2-ME-SAM). The surface concentration of the CoTCACIPc was found to be 4.58 × 10−10 mol/cm2. The sensor gave a linear response to L-cysteine over the concentration range 0.28–20 μM with a detection limit of 5 × 10−7 M and best response time of 2 s.
- Full Text:
- Date Issued: 2006
Self-assembled monolayers and electropolymerized thin films of phthalocyanines as molecular materials for electroanalysis
- Nyokong, Tebello, Bedioui, Fethi
- Authors: Nyokong, Tebello , Bedioui, Fethi
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283826 , vital:55994 , xlink:href="https://doi.org/10.1142/S1088424606000454"
- Description: In this review, we report on the newly developed area of research devoted to the formation of self-assembled monolayers of metallophthalocyanines by focusing on some significant examples dedicated to electroanalytical applications. We also summarize recent examples on the use of electropolymerized metallophthalocyanine films in electroanalysis. In both cases, activation and detection of thiols are the main targeted applications.
- Full Text:
- Date Issued: 2006
- Authors: Nyokong, Tebello , Bedioui, Fethi
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283826 , vital:55994 , xlink:href="https://doi.org/10.1142/S1088424606000454"
- Description: In this review, we report on the newly developed area of research devoted to the formation of self-assembled monolayers of metallophthalocyanines by focusing on some significant examples dedicated to electroanalytical applications. We also summarize recent examples on the use of electropolymerized metallophthalocyanine films in electroanalysis. In both cases, activation and detection of thiols are the main targeted applications.
- Full Text:
- Date Issued: 2006
Self-assembled monolayers and electropolymerized thin films of phthalocyanines as molecular materials for electroanalysis
- Nyokong, Tebello, Bedioui, Fethi
- Authors: Nyokong, Tebello , Bedioui, Fethi
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283851 , vital:55996 , xlink:href="https://doi.org/10.1142/S1088424606000454"
- Description: In this review, we report on the newly developed area of research devoted to the formation of self-assembled monolayers of metallophthalocyanines by focusing on some significant examples dedicated to electroanalytical applications. We also summarize recent examples on the use of electropolymerized metallophthalocyanine films in electroanalysis. In both cases, activation and detection of thiols are the main targeted applications.
- Full Text:
- Date Issued: 2006
- Authors: Nyokong, Tebello , Bedioui, Fethi
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283851 , vital:55996 , xlink:href="https://doi.org/10.1142/S1088424606000454"
- Description: In this review, we report on the newly developed area of research devoted to the formation of self-assembled monolayers of metallophthalocyanines by focusing on some significant examples dedicated to electroanalytical applications. We also summarize recent examples on the use of electropolymerized metallophthalocyanine films in electroanalysis. In both cases, activation and detection of thiols are the main targeted applications.
- Full Text:
- Date Issued: 2006
Situated environmental learning in Southern Africa at the start of the UN decade of education for sustainable development
- O'Donoghue, Rob B, Lotz-Sisitka, Heila
- Authors: O'Donoghue, Rob B , Lotz-Sisitka, Heila
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183059 , vital:43908 , xlink:href="https://doi.org/10.1017/S0814062600001737"
- Description: Within the globalising trajectory of modernism, conservation, then environmental (EE) and now sustainability education (ESD) have each emerged as developing responses to risk produced by and in the modern state. Through adopting a long term process perspective, this paper narrates the emergence of situated learning perspectives and a developing re-orientation of EE at the start of the United Nations Decade of Education for Sustainable Development (UNDESD). We identified the need to examine ESD practice in responses to recent ESD consultations in 14 southern African countries, where a rhetorical marking was noted in discussions on ESD practices, particularly with regard to changing teaching and learning processes. The paper narrates how an interplay of review, research and practical engagement activities have all contributed to an extended critical review of learning interactions in environmental education in an attempt to provide useful perspective for educational activities within the UNDESD. We found that EE and ESD initiatives only acquired more substantive meaning and coherent orientation when examined within ongoing inquiries into situated learning, agency and risk reduction in contexts of poverty, vulnerability and risk, the key concern to us in this paper and the primary focus of the WEHAB (Water, Energy, Health, Agriculture and Biodiversity) sustainable development agenda in the region.
- Full Text:
- Date Issued: 2006
- Authors: O'Donoghue, Rob B , Lotz-Sisitka, Heila
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183059 , vital:43908 , xlink:href="https://doi.org/10.1017/S0814062600001737"
- Description: Within the globalising trajectory of modernism, conservation, then environmental (EE) and now sustainability education (ESD) have each emerged as developing responses to risk produced by and in the modern state. Through adopting a long term process perspective, this paper narrates the emergence of situated learning perspectives and a developing re-orientation of EE at the start of the United Nations Decade of Education for Sustainable Development (UNDESD). We identified the need to examine ESD practice in responses to recent ESD consultations in 14 southern African countries, where a rhetorical marking was noted in discussions on ESD practices, particularly with regard to changing teaching and learning processes. The paper narrates how an interplay of review, research and practical engagement activities have all contributed to an extended critical review of learning interactions in environmental education in an attempt to provide useful perspective for educational activities within the UNDESD. We found that EE and ESD initiatives only acquired more substantive meaning and coherent orientation when examined within ongoing inquiries into situated learning, agency and risk reduction in contexts of poverty, vulnerability and risk, the key concern to us in this paper and the primary focus of the WEHAB (Water, Energy, Health, Agriculture and Biodiversity) sustainable development agenda in the region.
- Full Text:
- Date Issued: 2006
Spotlight on research: 50 years of Pharmaceutical Sciences Research Excellence Faculty of Pharmacy Rhodes University
- Authors: Walker, Roderick B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184243 , vital:44193 , xlink:href="https://hdl.handle.net/10520/EJC81478"
- Description: This year, the Faculty of Pharmacy at Rhodes University is celebrating its 50th Anniversary. Over 2000 BPharm, 33 BSc honours, 65 MSc and 27 PhD degrees have been conferred since the Faculty’s inception. The diverse research activities and dedicated academic staff have ensured that the Faculty of Pharmacy has high visibility with respect to research outputs, as is evidenced by the appointment of various members of staff to national and international research, regulatory and professional committees, as well as to serving on the editorial boards of a number of international journals. In addition, staff regularly publish in international and local peer-reviewed journals and present their research findings at international and local conferences.
- Full Text:
- Date Issued: 2006
- Authors: Walker, Roderick B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184243 , vital:44193 , xlink:href="https://hdl.handle.net/10520/EJC81478"
- Description: This year, the Faculty of Pharmacy at Rhodes University is celebrating its 50th Anniversary. Over 2000 BPharm, 33 BSc honours, 65 MSc and 27 PhD degrees have been conferred since the Faculty’s inception. The diverse research activities and dedicated academic staff have ensured that the Faculty of Pharmacy has high visibility with respect to research outputs, as is evidenced by the appointment of various members of staff to national and international research, regulatory and professional committees, as well as to serving on the editorial boards of a number of international journals. In addition, staff regularly publish in international and local peer-reviewed journals and present their research findings at international and local conferences.
- Full Text:
- Date Issued: 2006
Synthesis and electrochemical characterisation of α-and β-tetra-substituted oxo (phthalocyaninato) titanium (IV) complexes
- Tau, Prudence, Nyokong, Tebello
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283869 , vital:55998 , xlink:href="https://doi.org/10.1016/j.poly.2005.11.025"
- Description: The synthesis, spectroscopic and electrochemical characterisation of the following oxotitanium tetra-substituted phthalocyanines are reported: 1,(4)-(tetraphenoxyphthalocyaninato)titanium(IV) oxide (5a); 1,(4)-(tetra-tert-butylphenoxyphthalocyaninato)titanium(IV) oxide (5b); 2,(3)-(tetraphenoxyphthalocyaninato)titanium(IV) oxide (6a) and 2,(3)-(tetra-tert-butylphenoxyphthalocyaninato)titanium(IV) oxide (6b). Complexes 5a and 5b are substituted at the non-peripheral (α) positions, whereas complexes 6a and 6b are substituted at the peripheral (β) positions. Cyclic voltammograms of all four complexes are similar, with three reversible reduction couples and three quasi-reversible to irreversible oxidations. The first two reductions are two-electron processes, confirmed by spectroelectrochemistry to be due to TiIVPc−2/TiIIPc−3 and TiIIPc−2/TiIPc−3 redox processes. Spectroelectrochemistry showed that upon oxidation, the molecule decomposes. Oxidation is expected to occur at the ring. Chronocoulometry confirmed two electron transfer at the first and second reduction steps; and a one electron transfer at the third reduction.
- Full Text:
- Date Issued: 2006
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283869 , vital:55998 , xlink:href="https://doi.org/10.1016/j.poly.2005.11.025"
- Description: The synthesis, spectroscopic and electrochemical characterisation of the following oxotitanium tetra-substituted phthalocyanines are reported: 1,(4)-(tetraphenoxyphthalocyaninato)titanium(IV) oxide (5a); 1,(4)-(tetra-tert-butylphenoxyphthalocyaninato)titanium(IV) oxide (5b); 2,(3)-(tetraphenoxyphthalocyaninato)titanium(IV) oxide (6a) and 2,(3)-(tetra-tert-butylphenoxyphthalocyaninato)titanium(IV) oxide (6b). Complexes 5a and 5b are substituted at the non-peripheral (α) positions, whereas complexes 6a and 6b are substituted at the peripheral (β) positions. Cyclic voltammograms of all four complexes are similar, with three reversible reduction couples and three quasi-reversible to irreversible oxidations. The first two reductions are two-electron processes, confirmed by spectroelectrochemistry to be due to TiIVPc−2/TiIIPc−3 and TiIIPc−2/TiIPc−3 redox processes. Spectroelectrochemistry showed that upon oxidation, the molecule decomposes. Oxidation is expected to occur at the ring. Chronocoulometry confirmed two electron transfer at the first and second reduction steps; and a one electron transfer at the third reduction.
- Full Text:
- Date Issued: 2006
Synthesis and photophysical properties of octa-substituted phthalocyaninato oxotitanium (IV) derivatives
- Tau, Prudence, Nyokong, Tebello
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283881 , vital:55999 , xlink:href="https://doi.org/10.1142/S1088424606000399"
- Description: The synthesis, spectral and photophysical properties including fluorescence quenching of the following octa-substituted oxotitanium phthalocyanines are reported: 2,3,9,10,16,17,23,24-octaphenoxyphthalocyaninato titanium(IV) oxide, 2,3,9,10,16,17,23,24-[octakis(4-t-butylphenoxyphthalocyaninato)]titanium(IV) oxide, 2,3,9,10,16,17,23,24-{octakis[(4-benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide and 2,3,9,10,16,17,23,24-octaphenylthiophthalocyaninato titanium(IV) oxide. The complexes are characterized by 1H NMR, IR and UV-vis spectroscopies. Their photophysical properties are presented where moderate fluorescence quantum yields (0.14-0.19) and lifetimes were determined. Varied triplet quantum yields were obtained and the triplet lifetimes (40-100 μs) were short.
- Full Text:
- Date Issued: 2006
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283881 , vital:55999 , xlink:href="https://doi.org/10.1142/S1088424606000399"
- Description: The synthesis, spectral and photophysical properties including fluorescence quenching of the following octa-substituted oxotitanium phthalocyanines are reported: 2,3,9,10,16,17,23,24-octaphenoxyphthalocyaninato titanium(IV) oxide, 2,3,9,10,16,17,23,24-[octakis(4-t-butylphenoxyphthalocyaninato)]titanium(IV) oxide, 2,3,9,10,16,17,23,24-{octakis[(4-benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide and 2,3,9,10,16,17,23,24-octaphenylthiophthalocyaninato titanium(IV) oxide. The complexes are characterized by 1H NMR, IR and UV-vis spectroscopies. Their photophysical properties are presented where moderate fluorescence quantum yields (0.14-0.19) and lifetimes were determined. Varied triplet quantum yields were obtained and the triplet lifetimes (40-100 μs) were short.
- Full Text:
- Date Issued: 2006
Teacher education for Mathematical Literacy: a modelling approach
- Brown, Bruce J L, Schäfer, Marc
- Authors: Brown, Bruce J L , Schäfer, Marc
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141040 , vital:37939 , DOI: 10.4102/pythagoras.v0i64.98
- Description: This paper reports on a study of the extent to which question design affects the solution strategies adopted by children when solving linear number pattern generalisation tasks presented in pictorial and numeric contexts. The research tool comprised a series of 22 pencil-and-paper exercises based on linear generalisation tasks set in both numeric and two-dimensional pictorial contexts. The responses to these linear generalisation questions were classified by means of stage descriptors as well as stage modifiers. The method or strategy adopted was analysed and classified into one of seven categories. In addition, a meta-analysis focused on the formula derived for the nth term in conjunction with its justification. The results of this study strongly support the notion that question design can play a critical role in influencing learners' choice of strategy and level of attainment when solving pattern generalisation tasks. An understanding of the importance of appropriate question design has direct pedagogical application within the context of the mathematics classroom.
- Full Text:
- Date Issued: 2006
- Authors: Brown, Bruce J L , Schäfer, Marc
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141040 , vital:37939 , DOI: 10.4102/pythagoras.v0i64.98
- Description: This paper reports on a study of the extent to which question design affects the solution strategies adopted by children when solving linear number pattern generalisation tasks presented in pictorial and numeric contexts. The research tool comprised a series of 22 pencil-and-paper exercises based on linear generalisation tasks set in both numeric and two-dimensional pictorial contexts. The responses to these linear generalisation questions were classified by means of stage descriptors as well as stage modifiers. The method or strategy adopted was analysed and classified into one of seven categories. In addition, a meta-analysis focused on the formula derived for the nth term in conjunction with its justification. The results of this study strongly support the notion that question design can play a critical role in influencing learners' choice of strategy and level of attainment when solving pattern generalisation tasks. An understanding of the importance of appropriate question design has direct pedagogical application within the context of the mathematics classroom.
- Full Text:
- Date Issued: 2006
Teacher-community cooperation to promote sustainability of wetlands in Kenya
- Ndaruga, Ayub M, Irwin, Patrick R
- Authors: Ndaruga, Ayub M , Irwin, Patrick R
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373860 , vital:66728 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122727"
- Description: This study was undertaken with 83 teachers from 54 primary schools in Kenya. Its purpose was to establish how teachers relate with the local community and how they harness this interaction to promote sustainability of wetlands within their locality. Data were collected using questionnaires, interviews and observation. Results of the study indicated that teachers acknowledge the value of, and threats to, their local wetlands. Some teachers reported interacting and engaging in diverse activities with members of the community to conserve the local wetlands. Forums for interaction and action mentioned by the teachers included public baraza, women’s groups, church, youth groups, local community, parents’ meetings and environmental days. Use of these forums differed. The approaches used to involve the community in awareness and action ranged from theoretical arguments to visits to wetlands, use of wetland resources, ecomanagement and political action. The responses by teachers revealed lack of engagement with the real local wetland problems. This study demonstrated existence of a potential but under-utilised opportunity that can be harnessed by environmental education programmes to champion the sustainability of wetlands.
- Full Text:
- Date Issued: 2006
- Authors: Ndaruga, Ayub M , Irwin, Patrick R
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373860 , vital:66728 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122727"
- Description: This study was undertaken with 83 teachers from 54 primary schools in Kenya. Its purpose was to establish how teachers relate with the local community and how they harness this interaction to promote sustainability of wetlands within their locality. Data were collected using questionnaires, interviews and observation. Results of the study indicated that teachers acknowledge the value of, and threats to, their local wetlands. Some teachers reported interacting and engaging in diverse activities with members of the community to conserve the local wetlands. Forums for interaction and action mentioned by the teachers included public baraza, women’s groups, church, youth groups, local community, parents’ meetings and environmental days. Use of these forums differed. The approaches used to involve the community in awareness and action ranged from theoretical arguments to visits to wetlands, use of wetland resources, ecomanagement and political action. The responses by teachers revealed lack of engagement with the real local wetland problems. This study demonstrated existence of a potential but under-utilised opportunity that can be harnessed by environmental education programmes to champion the sustainability of wetlands.
- Full Text:
- Date Issued: 2006
The Condictio Indebiti and Unjust Factors (1)
- Authors: Glover, Graham B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186869 , vital:44541 , xlink:href="file:///C:/Users/User/Downloads/69THRHR419%20(2).pdf"
- Description: Since the Supreme Court of Appeal has continued to avoid taking the step of recognising a general enrichment action,' the traditional enrichment actions of the common law remain fundamentally important to the operation of the law of unjustified enrichment in South Africa. Most significant of these is the condictio indebiti, which is probably the most well-known and liberally utilised enrichment action in South African law.2 In this article, the nature and scope of this condictio will be examined, and it will be shown that it has grown beyond its notionally traditional role of reversing payments or transfers made unjustifiably by mistake, to include causes of action in duress and protest. The implications of this for the condictio, as well as for the foundations of our enrichment law will then be examined, with reference to the two leading schools of enrichment law: the civilian school, typified by German law, and the common-law school, typified by English law.
- Full Text:
- Date Issued: 2006
- Authors: Glover, Graham B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186869 , vital:44541 , xlink:href="file:///C:/Users/User/Downloads/69THRHR419%20(2).pdf"
- Description: Since the Supreme Court of Appeal has continued to avoid taking the step of recognising a general enrichment action,' the traditional enrichment actions of the common law remain fundamentally important to the operation of the law of unjustified enrichment in South Africa. Most significant of these is the condictio indebiti, which is probably the most well-known and liberally utilised enrichment action in South African law.2 In this article, the nature and scope of this condictio will be examined, and it will be shown that it has grown beyond its notionally traditional role of reversing payments or transfers made unjustifiably by mistake, to include causes of action in duress and protest. The implications of this for the condictio, as well as for the foundations of our enrichment law will then be examined, with reference to the two leading schools of enrichment law: the civilian school, typified by German law, and the common-law school, typified by English law.
- Full Text:
- Date Issued: 2006
The Condictio Indebiti and Unjust Factors (2)
- Authors: Glover, Graham B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186880 , vital:44544 , xlink:href="///C:/Users/User/Downloads/69THRHR561%20(1).pdf"
- Description: Since the Supreme Court of Appeal has continued to avoid taking the step of recognising a general enrichment action,' the traditional enrichment actions of the common law remain fundamentally important to the operation of the law of unjustified enrichment in South Africa. Most significant of these is the condictio indebiti, which is probably the most well-known and liberally utilised enrichment action in South African law.2 In this article, the nature and scope of this condictio will be examined, and it will be shown that it has grown beyond its notionally traditional role of reversing payments or transfers made unjustifiably by mistake, to include causes of action in duress and protest. The implications of this for the condictio, as well as for the foundations of our enrichment law will then be examined, with reference to the two leading schools of enrichment law: the civilian school, typified by German law, and the common-law school, typified by English law.
- Full Text:
- Date Issued: 2006
- Authors: Glover, Graham B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186880 , vital:44544 , xlink:href="///C:/Users/User/Downloads/69THRHR561%20(1).pdf"
- Description: Since the Supreme Court of Appeal has continued to avoid taking the step of recognising a general enrichment action,' the traditional enrichment actions of the common law remain fundamentally important to the operation of the law of unjustified enrichment in South Africa. Most significant of these is the condictio indebiti, which is probably the most well-known and liberally utilised enrichment action in South African law.2 In this article, the nature and scope of this condictio will be examined, and it will be shown that it has grown beyond its notionally traditional role of reversing payments or transfers made unjustifiably by mistake, to include causes of action in duress and protest. The implications of this for the condictio, as well as for the foundations of our enrichment law will then be examined, with reference to the two leading schools of enrichment law: the civilian school, typified by German law, and the common-law school, typified by English law.
- Full Text:
- Date Issued: 2006
The distribution and abundance of the endangered Knysna seahorse Hippocampus capensis (Pisces: Syngnathidae) in South African estuaries
- Lockyear, Jacqueline F, Hecht, Thomas, Kaiser, Horst, Teske, Peter R
- Authors: Lockyear, Jacqueline F , Hecht, Thomas , Kaiser, Horst , Teske, Peter R
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445714 , vital:74416 , https://doi.org/10.2989/16085910609503897
- Description: The occurrence, distribution and abundance of the endangered Knysna seahorse Hippocampus capensis in 10 estuaries on South Africa's warm temperate south coast, were investigated. Seahorses were found only in the Knysna, Swartvlei and Keurbooms estuaries. Sex ratios were even and, in most cases, more adults were found than juveniles. During the first year of study, seahorse densities were higher in the Swartvlei and Keurbooms estuaries than in the comparatively larger Knysna Estuary but, during the second year, seahorses were absent from the Keurbooms estuary, and the population size in the Swartvlei Estuary had decreased by more than 80%. These results suggest that, although the two smaller estuaries are able to support comparatively high densities of seahorses, population sizes may fluctuate considerably. Population size estimates for the Knysna Estuary were similar to those obtained in a previous study, suggesting that this estuary may represent a more stable environment and may thus be particularly important for the survival and conservation of this species.
- Full Text:
- Date Issued: 2006
- Authors: Lockyear, Jacqueline F , Hecht, Thomas , Kaiser, Horst , Teske, Peter R
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445714 , vital:74416 , https://doi.org/10.2989/16085910609503897
- Description: The occurrence, distribution and abundance of the endangered Knysna seahorse Hippocampus capensis in 10 estuaries on South Africa's warm temperate south coast, were investigated. Seahorses were found only in the Knysna, Swartvlei and Keurbooms estuaries. Sex ratios were even and, in most cases, more adults were found than juveniles. During the first year of study, seahorse densities were higher in the Swartvlei and Keurbooms estuaries than in the comparatively larger Knysna Estuary but, during the second year, seahorses were absent from the Keurbooms estuary, and the population size in the Swartvlei Estuary had decreased by more than 80%. These results suggest that, although the two smaller estuaries are able to support comparatively high densities of seahorses, population sizes may fluctuate considerably. Population size estimates for the Knysna Estuary were similar to those obtained in a previous study, suggesting that this estuary may represent a more stable environment and may thus be particularly important for the survival and conservation of this species.
- Full Text:
- Date Issued: 2006
The effect of Ge, Si and Sn phthalocyanine photosensitizers on cell proliferation and viability of human oesophageal carcinoma cells
- Seotsanyana-Mokhosi, Itumeleng, Kresfelder, Tina, Abrahamse, Heidi, Nyokong, Tebello
- Authors: Seotsanyana-Mokhosi, Itumeleng , Kresfelder, Tina , Abrahamse, Heidi , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/286115 , vital:56241 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2005.12.004"
- Description: The photodynamic activity of water soluble mixed sulfonated metallophthalocyanines complexes: GePcSmix, SnPcSmix and SiPcSmix on human oesophageal carcinoma (SNO) cells are reported, and compared with the activity of the unmetallated H2PcSmix and of the newly synthesized water soluble adjacently substituted binaphthalo phthalocyanine (complex 3). The alkaline phosphate (ALP) showed damage to the cell membrane in the presence of complex 3 without irradiation. The GePcSmix complex caused a relatively large increase in inflammation and a high intracellular ATP.
- Full Text:
- Date Issued: 2006
- Authors: Seotsanyana-Mokhosi, Itumeleng , Kresfelder, Tina , Abrahamse, Heidi , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/286115 , vital:56241 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2005.12.004"
- Description: The photodynamic activity of water soluble mixed sulfonated metallophthalocyanines complexes: GePcSmix, SnPcSmix and SiPcSmix on human oesophageal carcinoma (SNO) cells are reported, and compared with the activity of the unmetallated H2PcSmix and of the newly synthesized water soluble adjacently substituted binaphthalo phthalocyanine (complex 3). The alkaline phosphate (ALP) showed damage to the cell membrane in the presence of complex 3 without irradiation. The GePcSmix complex caused a relatively large increase in inflammation and a high intracellular ATP.
- Full Text:
- Date Issued: 2006
The effect of water hyacinth, Eichhornia crassipes (Martius) SolmsLaubach (Pontederiaceae), on benthic biodiversity in two impoundments on the New Year's River, South Africa
- Midgley, John M, Hill, Martin P, Villet, Martin H
- Authors: Midgley, John M , Hill, Martin P , Villet, Martin H
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442358 , vital:73978 , https://doi.org/10.2989/16085910609503868
- Description: Water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae), forms thick mats that affect water resource utilisation, but little is known about its impacts on biodiversity in aquatic ecosystems. The benthic invertebrate community and algal biomass were sampled under water hyacinth mats and in water hyacinth-free water over a 13-month period, using artificial substrates in New Year's Dam, Eastern Cape Province, South Africa. The number of families per substrate (U = 796.5, P 0.001), number of individuals per substrate (U = 620.5, P 0.001), Shannon-Weiner Diversity Index (U = 1 038, P 0.001), Margalef's Richness index (U = 1 136, P 0.002), Pielou's Evenness Index (U = 1 230, P 0.001) and chlorophyll a (U = 678, P 0.01) were all significantly lower under water hyacinth mats than in water hyacinth-free zones. Similarly, multivariate analyses showed more diversity in invertebrate communities in open water than under water hyacinth. Thus, the control of water hyacinth is important, in order to prevent both ecological and economic impacts of biodiversity loss.
- Full Text:
- Date Issued: 2006
- Authors: Midgley, John M , Hill, Martin P , Villet, Martin H
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442358 , vital:73978 , https://doi.org/10.2989/16085910609503868
- Description: Water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae), forms thick mats that affect water resource utilisation, but little is known about its impacts on biodiversity in aquatic ecosystems. The benthic invertebrate community and algal biomass were sampled under water hyacinth mats and in water hyacinth-free water over a 13-month period, using artificial substrates in New Year's Dam, Eastern Cape Province, South Africa. The number of families per substrate (U = 796.5, P 0.001), number of individuals per substrate (U = 620.5, P 0.001), Shannon-Weiner Diversity Index (U = 1 038, P 0.001), Margalef's Richness index (U = 1 136, P 0.002), Pielou's Evenness Index (U = 1 230, P 0.001) and chlorophyll a (U = 678, P 0.01) were all significantly lower under water hyacinth mats than in water hyacinth-free zones. Similarly, multivariate analyses showed more diversity in invertebrate communities in open water than under water hyacinth. Thus, the control of water hyacinth is important, in order to prevent both ecological and economic impacts of biodiversity loss.
- Full Text:
- Date Issued: 2006
The identification of mammalian species through the classification of hair patterns using image pattern recognition
- Moyo, Thamasanqa, Bangay, Shaun D, Foster, Gregory G
- Authors: Moyo, Thamasanqa , Bangay, Shaun D , Foster, Gregory G
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432938 , vital:72914 , https://doi.org/10.1145/1108590.1108619
- Description: The identification of mammals through the use of their hair is important in the fields of forensics and ecology. The application of computer pattern recognition techniques to this process provides a means of reducing the subjectivity found in the process, as manual techniques rely on the interpretation of a human expert rather than quantitative measures. The first application of image pattern recognition techniques to the classification of African mammalian species using hair patterns is presented. This application uses a 2D Gabor filter-bank and motivates the use of moments to classify hair scale patterns. Application of a 2D Gabor filter-bank to hair scale processing provides results of 52% accuracy when using a filter-bank of size four and 72% accuracy when using a filter-bank of size eight. These initial results indicate that 2D Gabor filters produce information that may be successfully used to classify hair according to images of its patterns.
- Full Text:
- Date Issued: 2006
- Authors: Moyo, Thamasanqa , Bangay, Shaun D , Foster, Gregory G
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432938 , vital:72914 , https://doi.org/10.1145/1108590.1108619
- Description: The identification of mammals through the use of their hair is important in the fields of forensics and ecology. The application of computer pattern recognition techniques to this process provides a means of reducing the subjectivity found in the process, as manual techniques rely on the interpretation of a human expert rather than quantitative measures. The first application of image pattern recognition techniques to the classification of African mammalian species using hair patterns is presented. This application uses a 2D Gabor filter-bank and motivates the use of moments to classify hair scale patterns. Application of a 2D Gabor filter-bank to hair scale processing provides results of 52% accuracy when using a filter-bank of size four and 72% accuracy when using a filter-bank of size eight. These initial results indicate that 2D Gabor filters produce information that may be successfully used to classify hair according to images of its patterns.
- Full Text:
- Date Issued: 2006
The inducement of a contract by duress of goods - a reappraisal
- Authors: Glover, Graham B
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70734 , vital:29722 , https://hdl.handle.net/10520/EJC54192
- Full Text: false
- Date Issued: 2006
- Authors: Glover, Graham B
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70734 , vital:29722 , https://hdl.handle.net/10520/EJC54192
- Full Text: false
- Date Issued: 2006
The influence of selected environmental parameters on the distribution of the dominant demersal fishes in the Kariega Estuary channel, South Africa
- Richardson, Naomi, Whitfield, Alan K, Paterson, Angus W
- Authors: Richardson, Naomi , Whitfield, Alan K , Paterson, Angus W
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447595 , vital:74659 , https://doi.org/10.1080/15627020.2006.11407339
- Description: The Kariega Estuary channel was sampled using an otter trawl and the demersal fish catch analysed using the PRIMER statistical package. A biological-environmental (BIOENV) analysis was undertaken using the catch per unit effort ichthyofaunal data from the spring/summer period of 1996/97 and concurrent water temperature, salinity and turbidity data. No strong correlations between the ichthyofauna and recorded physico-chemical parameters were documented, although temperature did show a weak correlation to demersal fish distributions. A second sampling programme undertaken in 2004 was specifically designed to test the influence of sedimentary characteristics on the distribution patterns of the dominant demersal species.
- Full Text:
- Date Issued: 2006
- Authors: Richardson, Naomi , Whitfield, Alan K , Paterson, Angus W
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447595 , vital:74659 , https://doi.org/10.1080/15627020.2006.11407339
- Description: The Kariega Estuary channel was sampled using an otter trawl and the demersal fish catch analysed using the PRIMER statistical package. A biological-environmental (BIOENV) analysis was undertaken using the catch per unit effort ichthyofaunal data from the spring/summer period of 1996/97 and concurrent water temperature, salinity and turbidity data. No strong correlations between the ichthyofauna and recorded physico-chemical parameters were documented, although temperature did show a weak correlation to demersal fish distributions. A second sampling programme undertaken in 2004 was specifically designed to test the influence of sedimentary characteristics on the distribution patterns of the dominant demersal species.
- Full Text:
- Date Issued: 2006
The Need for Centralised, Cross Platform Information Aggregation
- Otten, Fred, Irwin, Barry V W, Slay, Hannah
- Authors: Otten, Fred , Irwin, Barry V W , Slay, Hannah
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428773 , vital:72535 , https://d1wqtxts1xzle7.cloudfront.net/2355475/8jlt6v8tz4wmhs6.pdf?1425084143=response-content-disposi-tion=inline%3B+filename%3DThe_need_for_centralised_cross_platform.pdfExpires=1714743760Signature=fsImuFaOfYc2FtUC88DqRrK1Anh84~rvBsZt2j46BfPyKMbbmswGZN5E2ajRJ7tZi5SZ4zQJvI5U6L47nmoXlNA0~Vo3pON-sYEo6Kn3TiTLvxwUpPQALnP7IvL-EEhgh11T-OuNZf0Q8QArxk6iqi4zjiOYbHUb~FDWw8MJ7ekH~frNS75mDrjpZ4xL8MqPNRHctaR3E5m~4i71SYO8hfbZw4vu7AhNNNvrRoIhbtLCEUsg-j7TkBDgVHts8LCsM5knmEKwgQTSBQTkLoRuNmXngqYikjvL7jUuHXibjSVaMSD78WRqXE~LDDkT7KXU7EbkPXzjRYJyamQ5qDXa3A__ey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: With the move towards global and multi-national companies, information technology infrastructure requirements are increasing. As the size of these computer networks increases, it becomes more and more difficult to moni-tor, control, and secure them. Network security involves the creation of large amounts of information in the form of logs and messages from a number of diverse devices, sensors, and gateways which are often spread over large geographical areas. This makes the monitoring and control difficult, and hence poses security problems. The aggregation of information is necessary in information audits, intrusion detection, network monitoring and management. The use of different platforms and devices complicates the problem, and makes aggregation more difficult. Network security administrators and security researchers require aggregation to simplify the analysis and comprehension of activity across the entire net-work. Centralised information aggregation will help deal with redundancy, analysis, monitoring and control. This aids the detection of wide spread attacks on global organisational networks, improving intrusion detection and mitigation. This paper discusses and motivates the need for central-ised, cross platform information aggregation in greater detail. It also sug-gests methods which may be used, discusses the security issues, and gives the advantages and disadvantages of aggregation.
- Full Text:
- Date Issued: 2006
- Authors: Otten, Fred , Irwin, Barry V W , Slay, Hannah
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428773 , vital:72535 , https://d1wqtxts1xzle7.cloudfront.net/2355475/8jlt6v8tz4wmhs6.pdf?1425084143=response-content-disposi-tion=inline%3B+filename%3DThe_need_for_centralised_cross_platform.pdfExpires=1714743760Signature=fsImuFaOfYc2FtUC88DqRrK1Anh84~rvBsZt2j46BfPyKMbbmswGZN5E2ajRJ7tZi5SZ4zQJvI5U6L47nmoXlNA0~Vo3pON-sYEo6Kn3TiTLvxwUpPQALnP7IvL-EEhgh11T-OuNZf0Q8QArxk6iqi4zjiOYbHUb~FDWw8MJ7ekH~frNS75mDrjpZ4xL8MqPNRHctaR3E5m~4i71SYO8hfbZw4vu7AhNNNvrRoIhbtLCEUsg-j7TkBDgVHts8LCsM5knmEKwgQTSBQTkLoRuNmXngqYikjvL7jUuHXibjSVaMSD78WRqXE~LDDkT7KXU7EbkPXzjRYJyamQ5qDXa3A__ey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: With the move towards global and multi-national companies, information technology infrastructure requirements are increasing. As the size of these computer networks increases, it becomes more and more difficult to moni-tor, control, and secure them. Network security involves the creation of large amounts of information in the form of logs and messages from a number of diverse devices, sensors, and gateways which are often spread over large geographical areas. This makes the monitoring and control difficult, and hence poses security problems. The aggregation of information is necessary in information audits, intrusion detection, network monitoring and management. The use of different platforms and devices complicates the problem, and makes aggregation more difficult. Network security administrators and security researchers require aggregation to simplify the analysis and comprehension of activity across the entire net-work. Centralised information aggregation will help deal with redundancy, analysis, monitoring and control. This aids the detection of wide spread attacks on global organisational networks, improving intrusion detection and mitigation. This paper discusses and motivates the need for central-ised, cross platform information aggregation in greater detail. It also sug-gests methods which may be used, discusses the security issues, and gives the advantages and disadvantages of aggregation.
- Full Text:
- Date Issued: 2006
The Representation of, and Control over Mixing Desks via a Software-Based Matrix
- Foss, Richard, Foulkes, Phillip
- Authors: Foss, Richard , Foulkes, Phillip
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427306 , vital:72429 , https://www.aes.org/e-lib/browse.cfm?elib=13701
- Description: The control over all the parameters of a mixing desk can be a daunting task. This paper describes a software system that has been created to represent the signal processing and routing functions of MIDI-controllable mixing desks in a conceptually clear manner. Input to output routings are displayed in the form of a matrix, while signal processing functionality can be accessed at the inputs, outputs, and cross-points. XML is used to capture the elements of the mixing desk, and to associate appropriate MIDI control messages with these elements. This enables the same matrix template to be used for many mixing desks. Remote control is enabled by IP-based MIDI routing software known as MIDINet.
- Full Text:
- Date Issued: 2006
- Authors: Foss, Richard , Foulkes, Phillip
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427306 , vital:72429 , https://www.aes.org/e-lib/browse.cfm?elib=13701
- Description: The control over all the parameters of a mixing desk can be a daunting task. This paper describes a software system that has been created to represent the signal processing and routing functions of MIDI-controllable mixing desks in a conceptually clear manner. Input to output routings are displayed in the form of a matrix, while signal processing functionality can be accessed at the inputs, outputs, and cross-points. XML is used to capture the elements of the mixing desk, and to associate appropriate MIDI control messages with these elements. This enables the same matrix template to be used for many mixing desks. Remote control is enabled by IP-based MIDI routing software known as MIDINet.
- Full Text:
- Date Issued: 2006
The sharing of pension benefits on divorce: An inevitable affair?
- Authors: Glover, Graham B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186723 , vital:44528 , xlink:href="Print only"
- Description: One of the invariable consequences of divorce is that the patrimonial assets of the marriage have to be divided up between the two parties. At a primary level, the way in which this will occur will be determined by a number of factors: the matrimonial property regime under which the parties had been married; the relevant provisions of the Divorce Act (Act 70 of 1979) that deal with the question of the patrimonial consequences of divorce; as well as any agreement on this often ticklish matter that can be reached by the parties prior to the divorce action. Approximately fourteen years ago, section 7 of the Divorce Act was amended to allow a divorced spouse to share in the pension interests of the other spouse. There is some polemic, though, as to the interpretation of this provision: in particular, it is not clear whether this pension benefit will automatically form part of the assets that are susceptible to division, or whether a prayer to this effect must specifically be sought. After a consideration of the current legal position regarding the sharing of pension benefits generally, this note will examine this specific debate.
- Full Text:
- Date Issued: 2006
- Authors: Glover, Graham B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186723 , vital:44528 , xlink:href="Print only"
- Description: One of the invariable consequences of divorce is that the patrimonial assets of the marriage have to be divided up between the two parties. At a primary level, the way in which this will occur will be determined by a number of factors: the matrimonial property regime under which the parties had been married; the relevant provisions of the Divorce Act (Act 70 of 1979) that deal with the question of the patrimonial consequences of divorce; as well as any agreement on this often ticklish matter that can be reached by the parties prior to the divorce action. Approximately fourteen years ago, section 7 of the Divorce Act was amended to allow a divorced spouse to share in the pension interests of the other spouse. There is some polemic, though, as to the interpretation of this provision: in particular, it is not clear whether this pension benefit will automatically form part of the assets that are susceptible to division, or whether a prayer to this effect must specifically be sought. After a consideration of the current legal position regarding the sharing of pension benefits generally, this note will examine this specific debate.
- Full Text:
- Date Issued: 2006