A study of the photophysicochemical and antimicrobial properties of two zinc phthalocyanine–silver nanoparticle conjugates
- Rapulenyane, Nomasonto, Antunes, Edith M, Nyokong, Tebello
- Authors: Rapulenyane, Nomasonto , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232522 , vital:49999 , xlink:href="https://doi.org/10.1039/C3NJ41107A"
- Description: This work reports conjugation of two mono carboxy substituted zinc phthalocyanines with glutathione capped silver nanoparticles (GSH-AgNPs). The photophysicochemical behaviour of the novel phthalocyanines–silver nanoparticle conjugates was investigated together with simple mixtures of the silver nanoparticles with low symmetry phthalocyanines (i.e. with no direct chemical bond formation). It was observed that upon conjugation of the phthalocyanines to the silver nanoparticles, a blue shifting of the Q band was induced. The triplet lifetimes and quantum yields improved upon conjugation as compared to the phthalocyanines alone. Fluorescence lifetimes and quantum yields decreased for conjugates compared to the phthalocyanines alone due to quenching caused by the silver nanoparticles. The low symmetry phthalocyanines and their conjugates showed antimicrobial activity against Escherichia coli in the presence and absence of light.
- Full Text:
- Date Issued: 2013
- Authors: Rapulenyane, Nomasonto , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232522 , vital:49999 , xlink:href="https://doi.org/10.1039/C3NJ41107A"
- Description: This work reports conjugation of two mono carboxy substituted zinc phthalocyanines with glutathione capped silver nanoparticles (GSH-AgNPs). The photophysicochemical behaviour of the novel phthalocyanines–silver nanoparticle conjugates was investigated together with simple mixtures of the silver nanoparticles with low symmetry phthalocyanines (i.e. with no direct chemical bond formation). It was observed that upon conjugation of the phthalocyanines to the silver nanoparticles, a blue shifting of the Q band was induced. The triplet lifetimes and quantum yields improved upon conjugation as compared to the phthalocyanines alone. Fluorescence lifetimes and quantum yields decreased for conjugates compared to the phthalocyanines alone due to quenching caused by the silver nanoparticles. The low symmetry phthalocyanines and their conjugates showed antimicrobial activity against Escherichia coli in the presence and absence of light.
- Full Text:
- Date Issued: 2013
A tale of two neglected systems-structure and function of the thin- and thick-walled sieve tubes in monocotyledonous leaves
- Authors: Botha, Christiaan E J
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:6499 , http://hdl.handle.net/10962/d1004514 , http://dx.doi.org/10.3389/fpls.2013.00297
- Description: There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5–7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer.
- Full Text:
- Date Issued: 2013
- Authors: Botha, Christiaan E J
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:6499 , http://hdl.handle.net/10962/d1004514 , http://dx.doi.org/10.3389/fpls.2013.00297
- Description: There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5–7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer.
- Full Text:
- Date Issued: 2013
Academic freedom and the enclosure of knowledge in the global university
- Authors: Federici, Sylvia
- Date: 2013
- Subjects: Academic Freedom -- South Africa Universities and colleges -- South Africa Equality Liberty Education and state -- South Africa Education, Higher -- South Africa
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/773 , vital:19989
- Description: A discussion of 'academic freedom' is timely as everywhere, across the planet, this long fought-for principle is under siege. Trends, already emerging in Africa in the 1980s, are extending to every part of the world, contributing to what we can call 'a global enclosure of knowledge. ' This is the restriction of access to education to the 'happy few,' as knowledge and education are becoming commodified and profitability is becoming the sole logic by which the university is structured. Here I examine the most salient ways in which academic freedom is affected by these developments (with special reference to the United States) and, most important, how we can resist them. First, however, I consider what we mean by 'academic freedom,' since it is a concept that has been evolving, taking on new meanings, and is presently used with different connotations.
- Full Text:
- Date Issued: 2013
- Authors: Federici, Sylvia
- Date: 2013
- Subjects: Academic Freedom -- South Africa Universities and colleges -- South Africa Equality Liberty Education and state -- South Africa Education, Higher -- South Africa
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/773 , vital:19989
- Description: A discussion of 'academic freedom' is timely as everywhere, across the planet, this long fought-for principle is under siege. Trends, already emerging in Africa in the 1980s, are extending to every part of the world, contributing to what we can call 'a global enclosure of knowledge. ' This is the restriction of access to education to the 'happy few,' as knowledge and education are becoming commodified and profitability is becoming the sole logic by which the university is structured. Here I examine the most salient ways in which academic freedom is affected by these developments (with special reference to the United States) and, most important, how we can resist them. First, however, I consider what we mean by 'academic freedom,' since it is a concept that has been evolving, taking on new meanings, and is presently used with different connotations.
- Full Text:
- Date Issued: 2013
Adsorption and separation of platinum and palladium by polyamine functionalized polystyrene-based beads and nanofibers
- Fayemi, Omolola E, Ogunlaja, Adeniyi S, Kempgens, Pierre F M, Antunes, Edith M, Torto, Nelson, Nyokong, Tebello, Tshentu, Zenixole R
- Authors: Fayemi, Omolola E , Ogunlaja, Adeniyi S , Kempgens, Pierre F M , Antunes, Edith M , Torto, Nelson , Nyokong, Tebello , Tshentu, Zenixole R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241694 , vital:50961 , xlink:href="https://doi.org/10.1016/j.mineng.2013.06.006"
- Description: Adsorption and separation of platinum and palladium chlorido species (PtCl62- and PdCl42-) on polystyrene beads as well as nanofibers functionalized with ammonium centres based on ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA) and tris-(2-aminoethyl)amine (TAEA) are described. The functionalized sorbent materials were characterized by microanalysis, SEM, XPS, BET and FTIR. The surface area of the functionalized fibers was in the range 69–241 m2/g while it was 73–107 m2/g for the beads. The adsorption and loading capacities of the sorption materials were investigated using both the batch and column studies at 1 M HCl concentration. The adsorption studies for both PtCl62- and PdCl42- on the different sorbent materials fit the Langmuir isotherm with R2 values >0.99. The highest loading capacity of Pt and Pd were 7.4 mg/g and 4.3 mg/g respectively for the nanofiber sorbent material based on ethylenediamine (EDA) while the beads with ethylenediamine (EDA) gave 1.0 mg/g and 0.2 mg/g for Pt and Pd respectively. Metals loaded on the sorbent materials were recovered by using 3% m/v thiourea solution as the eluting agent with quantitative desorption efficiency under the selected experimental conditions. Separation of platinum from palladium was partially achieved by selective stripping of PtCl62- with 0.5 M of NaClO4 in 1.0 M HCl while PdCl42- was eluted with 0.5 M thiourea in 1.0 M HCl. Separation of platinum from iridium and rhodium under 1 M HCl concentration was successful on triethylenetriamine (TETA)-functionalized Merrifield beads. This material (M-TETA) showed selectivity for platinum albeit the low loading capacity.
- Full Text:
- Date Issued: 2013
- Authors: Fayemi, Omolola E , Ogunlaja, Adeniyi S , Kempgens, Pierre F M , Antunes, Edith M , Torto, Nelson , Nyokong, Tebello , Tshentu, Zenixole R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241694 , vital:50961 , xlink:href="https://doi.org/10.1016/j.mineng.2013.06.006"
- Description: Adsorption and separation of platinum and palladium chlorido species (PtCl62- and PdCl42-) on polystyrene beads as well as nanofibers functionalized with ammonium centres based on ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA) and tris-(2-aminoethyl)amine (TAEA) are described. The functionalized sorbent materials were characterized by microanalysis, SEM, XPS, BET and FTIR. The surface area of the functionalized fibers was in the range 69–241 m2/g while it was 73–107 m2/g for the beads. The adsorption and loading capacities of the sorption materials were investigated using both the batch and column studies at 1 M HCl concentration. The adsorption studies for both PtCl62- and PdCl42- on the different sorbent materials fit the Langmuir isotherm with R2 values >0.99. The highest loading capacity of Pt and Pd were 7.4 mg/g and 4.3 mg/g respectively for the nanofiber sorbent material based on ethylenediamine (EDA) while the beads with ethylenediamine (EDA) gave 1.0 mg/g and 0.2 mg/g for Pt and Pd respectively. Metals loaded on the sorbent materials were recovered by using 3% m/v thiourea solution as the eluting agent with quantitative desorption efficiency under the selected experimental conditions. Separation of platinum from palladium was partially achieved by selective stripping of PtCl62- with 0.5 M of NaClO4 in 1.0 M HCl while PdCl42- was eluted with 0.5 M thiourea in 1.0 M HCl. Separation of platinum from iridium and rhodium under 1 M HCl concentration was successful on triethylenetriamine (TETA)-functionalized Merrifield beads. This material (M-TETA) showed selectivity for platinum albeit the low loading capacity.
- Full Text:
- Date Issued: 2013
Alternative/Experimental art spaces in Johannesburg:
- Authors: Malatjie, Portia
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147692 , vital:38661 , https://0-doi.org.wam.seals.ac.za/10.1080/09528822.2013.798181
- Description: There are a number of recent exciting developments in the Johannesburg alternative art scene. Alternative or experimental art spaces often exist as an alternative to commercial galleries and government or privately funded galleries as well as museums. They are therefore governed through a different set of rules, rules that often aim to transgress the institutional. These spaces, including the Parking Gallery, the Keleketla! Library and arguably the Wits School of Art's Substation gallery, invite debates about alternative art programming, collaborative art making and the necessity of institutional funding in order to maintain such spaces. In addition to these questions, it is pertinent to first determine what it is that classifies a space as alternative.
- Full Text:
- Date Issued: 2013
- Authors: Malatjie, Portia
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147692 , vital:38661 , https://0-doi.org.wam.seals.ac.za/10.1080/09528822.2013.798181
- Description: There are a number of recent exciting developments in the Johannesburg alternative art scene. Alternative or experimental art spaces often exist as an alternative to commercial galleries and government or privately funded galleries as well as museums. They are therefore governed through a different set of rules, rules that often aim to transgress the institutional. These spaces, including the Parking Gallery, the Keleketla! Library and arguably the Wits School of Art's Substation gallery, invite debates about alternative art programming, collaborative art making and the necessity of institutional funding in order to maintain such spaces. In addition to these questions, it is pertinent to first determine what it is that classifies a space as alternative.
- Full Text:
- Date Issued: 2013
An analysis of the distribution and use of teaching aids in mathematics in selected Windhoek secondary schools
- Authors: Dzambara, Tobias Munyaradzi
- Date: 2013
- Subjects: Mathematics -- Study and teaching (Secondary) -- Namibia Teaching -- Aids and devices -- Research
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: vital:1344 , http://hdl.handle.net/10962/d1001410
- Description: This study investigates the types of mathematics teaching aids available at both public and private secondary schools in Windhoek. The study characterises their usage and source as well as teachers’ perceptions towards the use of such teaching resources in the Mathematics classroom. The study is grounded in an interpretive paradigm and employed a mixed methods approach to generate both quantitative and qualitative data in two sequential phases. Phase 1 of the research process, which involved 75 Mathematics teachers, took the form of an audit of the availability and use of teaching aids at 25 secondary schools in Windhoek. A case study methodology was adopted in Phase 2 which focused on five purposively selected schools that displayed different characteristics in terms of the availability of teaching resources. The study found that the majority of teachers at secondary schools in Windhoek have a positive attitude towards the importance and role of teaching aids in Mathematics, seeing them as promoters of hands-on engagement, visual reasoning, active participation and motivation amongst learners. However, in some instances schools are underresourced with respect to certain types of teaching aids, specifically graph boards, geoboards, geometric models and computers. A need for appropriate in-school support on the use of teaching aids was also identified
- Full Text:
- Date Issued: 2013
- Authors: Dzambara, Tobias Munyaradzi
- Date: 2013
- Subjects: Mathematics -- Study and teaching (Secondary) -- Namibia Teaching -- Aids and devices -- Research
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: vital:1344 , http://hdl.handle.net/10962/d1001410
- Description: This study investigates the types of mathematics teaching aids available at both public and private secondary schools in Windhoek. The study characterises their usage and source as well as teachers’ perceptions towards the use of such teaching resources in the Mathematics classroom. The study is grounded in an interpretive paradigm and employed a mixed methods approach to generate both quantitative and qualitative data in two sequential phases. Phase 1 of the research process, which involved 75 Mathematics teachers, took the form of an audit of the availability and use of teaching aids at 25 secondary schools in Windhoek. A case study methodology was adopted in Phase 2 which focused on five purposively selected schools that displayed different characteristics in terms of the availability of teaching resources. The study found that the majority of teachers at secondary schools in Windhoek have a positive attitude towards the importance and role of teaching aids in Mathematics, seeing them as promoters of hands-on engagement, visual reasoning, active participation and motivation amongst learners. However, in some instances schools are underresourced with respect to certain types of teaching aids, specifically graph boards, geoboards, geometric models and computers. A need for appropriate in-school support on the use of teaching aids was also identified
- Full Text:
- Date Issued: 2013
An exploratory study of the impacts of climate variability on food production availability and access in Chivi district 6, Zimbabwe
- Authors: Gwindi, Raphael
- Date: 2013
- Subjects: Climatic changes , Food security , Agricultural development projects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26696 , vital:65852
- Description: The impacts of climate variability have been of global concern for many years. These impacts are affecting economic, social, cultural, agricultural, health and political structures in different countries. Although the impacts of climate variability on agricultural production are being experienced globally, it is generally accepted that developing countries are the worst affected due to a variety of reasons. Given the high susceptibility of developing countries to climate variability, this study maps and analyses the impacts of climate variability on agricultural production, food production, availability and access in Chivi District, Zimbabwe. The study aimed at finding out experiences, so it used a qualitative approach. The study uses in-depth and focus group discussions to collect data. Chivi district is experiencing erratic weather patterns which are impacting agricultural production in general and food production in particular. Consequently, food availability and access is on the decline in the district. Even though smallholder farmers have devised coping and adaptation strategies, this is not sufficient to help them fully deal with the impacts of climate variability. This is due to their limited assets, inadequate technology and climate information among other things. In an attempt to assist these smallholder farmers cope and adapt to the impacts of climate variability, NGOs and Government Departments have instituted a number of community interventions. This assistance includes agricultural extension services, farming input support and provision of climate change information and a lot of other things. In view of these findings, the study recommends the universal adoption and growing of small grain drought resistant crops in climate variability affected Chivi. It further recommends that farmers adopt conservation agriculture, get into partnerships and co-operatives to practice irrigation gardening where those without water sources provide equipment, labour and knowledge. The study also recommends that more climate science research be conducted in Zimbabwe by both NGOs and Government Departments. Furthermore, government and NGOs should provide more support for farmers in the form of climate change related training, knowledge and technology transfer among other things. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2013
- Full Text:
- Date Issued: 2013
- Authors: Gwindi, Raphael
- Date: 2013
- Subjects: Climatic changes , Food security , Agricultural development projects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26696 , vital:65852
- Description: The impacts of climate variability have been of global concern for many years. These impacts are affecting economic, social, cultural, agricultural, health and political structures in different countries. Although the impacts of climate variability on agricultural production are being experienced globally, it is generally accepted that developing countries are the worst affected due to a variety of reasons. Given the high susceptibility of developing countries to climate variability, this study maps and analyses the impacts of climate variability on agricultural production, food production, availability and access in Chivi District, Zimbabwe. The study aimed at finding out experiences, so it used a qualitative approach. The study uses in-depth and focus group discussions to collect data. Chivi district is experiencing erratic weather patterns which are impacting agricultural production in general and food production in particular. Consequently, food availability and access is on the decline in the district. Even though smallholder farmers have devised coping and adaptation strategies, this is not sufficient to help them fully deal with the impacts of climate variability. This is due to their limited assets, inadequate technology and climate information among other things. In an attempt to assist these smallholder farmers cope and adapt to the impacts of climate variability, NGOs and Government Departments have instituted a number of community interventions. This assistance includes agricultural extension services, farming input support and provision of climate change information and a lot of other things. In view of these findings, the study recommends the universal adoption and growing of small grain drought resistant crops in climate variability affected Chivi. It further recommends that farmers adopt conservation agriculture, get into partnerships and co-operatives to practice irrigation gardening where those without water sources provide equipment, labour and knowledge. The study also recommends that more climate science research be conducted in Zimbabwe by both NGOs and Government Departments. Furthermore, government and NGOs should provide more support for farmers in the form of climate change related training, knowledge and technology transfer among other things. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2013
- Full Text:
- Date Issued: 2013
An invader within an altered landscape: one catfish, two rivers and an inter-basin water transfer scheme
- Kadye, Wilbert T, Booth, Anthony J
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123776 , vital:35494 , https://doi.10.1002/rra.2599
- Description: African sharptooth catfish Clarias gariepinus has become established as a non-native invasive species in Eastern Cape, South Africa, where it was translocated primarily through an inter-basin water transfer scheme into the Great Fish and Sundays rivers. This study examined the patterns in catfish distribution and abundance, and compared trophic niches in relation to the ichthyofauna of the two rivers. Correspondence analysis revealed upstream to downstream gradients associated with the spatial distribution in species richness for most species within the mainstream and mainstream to tributary gradients that were associated mostly with the spatial distribution of native minnows in both rivers. Catfish was predicted to occur widely within the mainstream habitats and to decrease progressively from mainstreams to tributaries. Based on classification and regression trees, the physico-chemical environment was found to be a good proxy for predicting the occurrence and abundance of catfish. Although non-significant relationships were observed between catfish and other native fish species abundances, the study suggests potential impact due to predation and interference in habitats where the invader co-occurs with other fishes. Comparisons of trophic niches indicated higher trophic diversity for the mainstream ichthyofauna than the tributary communities in both rivers, suggesting an upstream to downstream continuum in community structure and resource availability. Catfish within the invaded mainstream had comparable trophic niches and similar dispersion patterns among individuals for both rivers, but indicated differences in shapes of scatter. This suggests that the catfish exhibited a differential response, probably in relation to resource availability, that may be indicative of its dietary plasticity. The study suggests the proliferation of catfish and its probable impact within the mainstream flow-altered habitats where invasion resistance was possibly reduced. Comparisons of trophic niches provided information on its probable impact at different scales and the potential risk of invasion of tributaries inhabited by native minnow species.
- Full Text:
- Date Issued: 2013
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123776 , vital:35494 , https://doi.10.1002/rra.2599
- Description: African sharptooth catfish Clarias gariepinus has become established as a non-native invasive species in Eastern Cape, South Africa, where it was translocated primarily through an inter-basin water transfer scheme into the Great Fish and Sundays rivers. This study examined the patterns in catfish distribution and abundance, and compared trophic niches in relation to the ichthyofauna of the two rivers. Correspondence analysis revealed upstream to downstream gradients associated with the spatial distribution in species richness for most species within the mainstream and mainstream to tributary gradients that were associated mostly with the spatial distribution of native minnows in both rivers. Catfish was predicted to occur widely within the mainstream habitats and to decrease progressively from mainstreams to tributaries. Based on classification and regression trees, the physico-chemical environment was found to be a good proxy for predicting the occurrence and abundance of catfish. Although non-significant relationships were observed between catfish and other native fish species abundances, the study suggests potential impact due to predation and interference in habitats where the invader co-occurs with other fishes. Comparisons of trophic niches indicated higher trophic diversity for the mainstream ichthyofauna than the tributary communities in both rivers, suggesting an upstream to downstream continuum in community structure and resource availability. Catfish within the invaded mainstream had comparable trophic niches and similar dispersion patterns among individuals for both rivers, but indicated differences in shapes of scatter. This suggests that the catfish exhibited a differential response, probably in relation to resource availability, that may be indicative of its dietary plasticity. The study suggests the proliferation of catfish and its probable impact within the mainstream flow-altered habitats where invasion resistance was possibly reduced. Comparisons of trophic niches provided information on its probable impact at different scales and the potential risk of invasion of tributaries inhabited by native minnow species.
- Full Text:
- Date Issued: 2013
An investigation of the discursive construction of the Tanganyika-Zanzibar Union as nation in the Union Day coverage in The Citizen and Daily News newspapers from 2005 to 2011
- Authors: Dotto, Paul Casmir Kuhenga
- Date: 2013
- Subjects: Newspapers -- Research -- Tanzania , Press and politics -- Tanzania , Tanzania -- Politics and government -- 1964- , Zanzibar -- Politics and government -- 1964- , Press , Daily News , The Citizen , Union Day , Nation building
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3412 , http://hdl.handle.net/10962/d1001843
- Description: This study is concerned with the constructions of the Tanzanian nation in the press. It has confined its focus, first, to the coverage from 2005 to 2011 on Union Day that marks the Union between Tanganyika and Zanzibar and the formation of the United Republic of Tanzania and, second, to two prominent Tanzanian newspapers, namely the state-owned Daily News, and the privately-owned The Citizen on Union Day. As the Union remains a contentious issue, the relevance of this research relates to the press’s considerable power to shape understandings and influence attitudes. The study works within a broad cultural and media studies framework and is informed by a constructionist approach to representation and to culture, and to nation in particular. It also draws of journalistic theories of agenda-setting and the normative roles of the press to probe the agendas set by the press on Union Day and to interrogate how the two newspapers construct and frame the Union of Tanganyika and Zanzibar as nation. The research responds to the question: ‘How has the Tanganyika-Zanzibar Union been represented in The Citizen and Daily News newspapers from 2005 to 2011?’ It employs quantitative and qualitative (thematic) content analysis to investigate the coverage in the editorials and feature articles of The Citizen and Daily News newspapers on Union Day (26 April) of 2005 to 2011. This study finds that the government-owned newspaper, Daily News, publishes more articles related to Union on Union Day than the privately-owned, The Citizen and collaborates more determinedly with the state in the process of constructing the nation. However, both newspapers adopt a collaborative role consistent with the development journalism tradition that endorses an informal partnership between media and the state in the process of development (Christians et al, 2009:201). Both publications tend to emphasise the hegemonic ideology pertaining to Union while giving limited attention to challenges to such constructions. While both newspapers do identify certain problems of the Union and thus exercise a monitorial role to varying extents, it is apparent that the press in Tanzania tends to be largely acritical, perhaps attributable to a long period under single party rule
- Full Text:
- Date Issued: 2013
- Authors: Dotto, Paul Casmir Kuhenga
- Date: 2013
- Subjects: Newspapers -- Research -- Tanzania , Press and politics -- Tanzania , Tanzania -- Politics and government -- 1964- , Zanzibar -- Politics and government -- 1964- , Press , Daily News , The Citizen , Union Day , Nation building
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3412 , http://hdl.handle.net/10962/d1001843
- Description: This study is concerned with the constructions of the Tanzanian nation in the press. It has confined its focus, first, to the coverage from 2005 to 2011 on Union Day that marks the Union between Tanganyika and Zanzibar and the formation of the United Republic of Tanzania and, second, to two prominent Tanzanian newspapers, namely the state-owned Daily News, and the privately-owned The Citizen on Union Day. As the Union remains a contentious issue, the relevance of this research relates to the press’s considerable power to shape understandings and influence attitudes. The study works within a broad cultural and media studies framework and is informed by a constructionist approach to representation and to culture, and to nation in particular. It also draws of journalistic theories of agenda-setting and the normative roles of the press to probe the agendas set by the press on Union Day and to interrogate how the two newspapers construct and frame the Union of Tanganyika and Zanzibar as nation. The research responds to the question: ‘How has the Tanganyika-Zanzibar Union been represented in The Citizen and Daily News newspapers from 2005 to 2011?’ It employs quantitative and qualitative (thematic) content analysis to investigate the coverage in the editorials and feature articles of The Citizen and Daily News newspapers on Union Day (26 April) of 2005 to 2011. This study finds that the government-owned newspaper, Daily News, publishes more articles related to Union on Union Day than the privately-owned, The Citizen and collaborates more determinedly with the state in the process of constructing the nation. However, both newspapers adopt a collaborative role consistent with the development journalism tradition that endorses an informal partnership between media and the state in the process of development (Christians et al, 2009:201). Both publications tend to emphasise the hegemonic ideology pertaining to Union while giving limited attention to challenges to such constructions. While both newspapers do identify certain problems of the Union and thus exercise a monitorial role to varying extents, it is apparent that the press in Tanzania tends to be largely acritical, perhaps attributable to a long period under single party rule
- Full Text:
- Date Issued: 2013
An overview of normative frameworks for the protection of development-induced IDPs in Kenya.
- Authors: Juma, Laurence
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127112 , vital:35957 , https://doi.org/10.1163/17087384-12342016
- Description: Based on the assumption that development induced displacement brings new challenges that the existing protection frameworks may not be aptly suited to deal with, this article analyses how the existing laws have met this challenge and the prospects for further improvement. While its focus is on Kenya, it evaluates the normative quality of protection and standards offered by regional instruments against the existing, as well emerging, parameters for implementation at the domestic level. In this regard, the article examines the propriety of Kenya’s newly promulgated law on internal displacement in providing for protection for the development induced IDPs, the implementation programme that it establishes and its prospects for furthering the vision of the UN Guiding Principles on Internally Displaced and other regional instruments.
- Full Text:
- Date Issued: 2013
- Authors: Juma, Laurence
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127112 , vital:35957 , https://doi.org/10.1163/17087384-12342016
- Description: Based on the assumption that development induced displacement brings new challenges that the existing protection frameworks may not be aptly suited to deal with, this article analyses how the existing laws have met this challenge and the prospects for further improvement. While its focus is on Kenya, it evaluates the normative quality of protection and standards offered by regional instruments against the existing, as well emerging, parameters for implementation at the domestic level. In this regard, the article examines the propriety of Kenya’s newly promulgated law on internal displacement in providing for protection for the development induced IDPs, the implementation programme that it establishes and its prospects for furthering the vision of the UN Guiding Principles on Internally Displaced and other regional instruments.
- Full Text:
- Date Issued: 2013
An Unprecedented 'Precedent'?: Phodiclinics (Pty) Ltd v Pinehaven Private Hospital (Pty) Ltd (594/2010)[2011] ZASCA163 (28 September 2011); 2011 4 All SA 331 (SCA)
- Authors: Glover, Graham B
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69950 , vital:29598 , https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2364288
- Description: There are some fundamental underlying requirements that need to be in place for a system of precedent to operate. Of these I wish to isolate two that are germane to this note. The first is that court decisions (especially those in which a written judgment is handed down) need to be clearly reasoned and logically articulated to be understandable, effective and to have value in a system of precedent that finds its ultimate lodestar in the rule of law. There is no constitutional or statutory requirement that a court in all cases must furnish reasons, or even written reasons, for its decision But the practice of doing so, the Constitutional Court has said, supports the rule of law, ensuring that judicial decision-making does not occur in a manner that is arbitrary, and ensures that judges may be held accountable for their decisions. The second requirement is a technical rule – the rule of majority: if the case is heard by a full bench, and where differing opinions are handed down by the judges hearing the case, the ratio decidendi can only be identified from those judges whose reasoning is in the majority.
- Full Text: false
- Date Issued: 2013
- Authors: Glover, Graham B
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69950 , vital:29598 , https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2364288
- Description: There are some fundamental underlying requirements that need to be in place for a system of precedent to operate. Of these I wish to isolate two that are germane to this note. The first is that court decisions (especially those in which a written judgment is handed down) need to be clearly reasoned and logically articulated to be understandable, effective and to have value in a system of precedent that finds its ultimate lodestar in the rule of law. There is no constitutional or statutory requirement that a court in all cases must furnish reasons, or even written reasons, for its decision But the practice of doing so, the Constitutional Court has said, supports the rule of law, ensuring that judicial decision-making does not occur in a manner that is arbitrary, and ensures that judges may be held accountable for their decisions. The second requirement is a technical rule – the rule of majority: if the case is heard by a full bench, and where differing opinions are handed down by the judges hearing the case, the ratio decidendi can only be identified from those judges whose reasoning is in the majority.
- Full Text: false
- Date Issued: 2013
Analysing learning at the interface of scientific and traditional ecological knowledge in a mangrove ecosystem restoration scenario in the eastern coast of Tanzania
- Sabai, Daniel, Sisitka, Heila
- Authors: Sabai, Daniel , Sisitka, Heila
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127179 , vital:35974 , https://doi.org/10.2478/trser-2013-0027
- Description: Records from community-based coastal management initiatives indicate that local communities who are key actors in activities that aim at safeguarding the health status of terrestrial and marine ecosystems face a lot of challenges associated with adapting andapplying indicators that are scientifically abstracted and methodologically too reified, given varying social, contextual and technical conditions prevailing amongst them. This paper brings into view possible challenges of adapting and applying scientific indicators in community-based monitoring of mangrove ecosystem and suggests a new approach that may lead to development of indicators which are less reified, more congruent to users (coastal communities) and likely to attract a wider social learning in the mangroverestoration context. It also sets a bridge for scientific institutions (including universities), tounderstand various social, cultural and contextual needs that determine epistemological access between them and local communities, which need to be addressed prior to engaging targetcommunities in participatory monitoring programmes.The paper attempts to analyse learning at the interface of knowledge that scientific institutions produce and the potential knowledge that exists in local context (traditional ecological knowledge) for purposes of widening and improving knowledge sharing and safeguarding the health status of mangrove species and fisheries that use them as key habitats. The paper stems from a study which employs processes of abstraction and experiential learning techniques such as Experiential Learning Intervention Workshop carried out in 2012,to unlock knowledge that local communities have, as an input for underlabouring existing scientific indicators in the eastern coast of Tanzania.It brings into view the need to consider contextual realities on ground, the level of education that the participating group has, the minimum level of participation that is required, structures that govern coastal monitoring practices at local level and the need for scientific institutions to consider the knowledge that local people have as an input for enhancing or improving coastal monitoring, especially monitoring of mangrove and fishery resources. The paper finally comes up with a framework of indicators which is regarded by coastal communities as being less reified, more contextually and culturally congruent and which can easily be used in detecting environmental trends, threats, changes and conditions of mangrove and fisheries resources, and attract wider social learning processes.
- Full Text:
- Date Issued: 2013
- Authors: Sabai, Daniel , Sisitka, Heila
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127179 , vital:35974 , https://doi.org/10.2478/trser-2013-0027
- Description: Records from community-based coastal management initiatives indicate that local communities who are key actors in activities that aim at safeguarding the health status of terrestrial and marine ecosystems face a lot of challenges associated with adapting andapplying indicators that are scientifically abstracted and methodologically too reified, given varying social, contextual and technical conditions prevailing amongst them. This paper brings into view possible challenges of adapting and applying scientific indicators in community-based monitoring of mangrove ecosystem and suggests a new approach that may lead to development of indicators which are less reified, more congruent to users (coastal communities) and likely to attract a wider social learning in the mangroverestoration context. It also sets a bridge for scientific institutions (including universities), tounderstand various social, cultural and contextual needs that determine epistemological access between them and local communities, which need to be addressed prior to engaging targetcommunities in participatory monitoring programmes.The paper attempts to analyse learning at the interface of knowledge that scientific institutions produce and the potential knowledge that exists in local context (traditional ecological knowledge) for purposes of widening and improving knowledge sharing and safeguarding the health status of mangrove species and fisheries that use them as key habitats. The paper stems from a study which employs processes of abstraction and experiential learning techniques such as Experiential Learning Intervention Workshop carried out in 2012,to unlock knowledge that local communities have, as an input for underlabouring existing scientific indicators in the eastern coast of Tanzania.It brings into view the need to consider contextual realities on ground, the level of education that the participating group has, the minimum level of participation that is required, structures that govern coastal monitoring practices at local level and the need for scientific institutions to consider the knowledge that local people have as an input for enhancing or improving coastal monitoring, especially monitoring of mangrove and fishery resources. The paper finally comes up with a framework of indicators which is regarded by coastal communities as being less reified, more contextually and culturally congruent and which can easily be used in detecting environmental trends, threats, changes and conditions of mangrove and fisheries resources, and attract wider social learning processes.
- Full Text:
- Date Issued: 2013
Analysis of protein thermostability enhancing factors in industrially important thermus bacteria species
- Kumwenda, Benjamin, Litthauer, Derek, Tastan Bishop, Özlem, Reva, Oleg
- Authors: Kumwenda, Benjamin , Litthauer, Derek , Tastan Bishop, Özlem , Reva, Oleg
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123085 , vital:35404 , https://doi.10.4137/EBO.S12539
- Description: Elucidation of evolutionary factors that enhance protein thermostability is a critical problem and was the focus of this work on Thermus species. Pairs of orthologous sequences of T. scotoductus SA-01 and T. thermophilus HB27, with the largest negative minimum folding energy (MFE) as predicted by the UNAFold algorithm, were statistically analyzed. Favored substitutions of amino acids residues and their properties were determined. Substitutions were analyzed in modeled protein structures to determine their locations and contribution to energy differences using PyMOL and FoldX programs respectively. Dominant trends in amino acid substitutions consistent with differences in thermostability between orthologous sequences were observed. T. thermophilus thermophilic proteins showed an increase in non-polar, tiny, and charged amino acids. An abundance of alanine substituted by serine and threonine, as well as arginine substituted by glutamine and lysine was observed in T. thermophilus HB27. Structural comparison showed that stabilizing mutations occurred on surfaces and loops in protein structures.
- Full Text:
- Date Issued: 2013
- Authors: Kumwenda, Benjamin , Litthauer, Derek , Tastan Bishop, Özlem , Reva, Oleg
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123085 , vital:35404 , https://doi.10.4137/EBO.S12539
- Description: Elucidation of evolutionary factors that enhance protein thermostability is a critical problem and was the focus of this work on Thermus species. Pairs of orthologous sequences of T. scotoductus SA-01 and T. thermophilus HB27, with the largest negative minimum folding energy (MFE) as predicted by the UNAFold algorithm, were statistically analyzed. Favored substitutions of amino acids residues and their properties were determined. Substitutions were analyzed in modeled protein structures to determine their locations and contribution to energy differences using PyMOL and FoldX programs respectively. Dominant trends in amino acid substitutions consistent with differences in thermostability between orthologous sequences were observed. T. thermophilus thermophilic proteins showed an increase in non-polar, tiny, and charged amino acids. An abundance of alanine substituted by serine and threonine, as well as arginine substituted by glutamine and lysine was observed in T. thermophilus HB27. Structural comparison showed that stabilizing mutations occurred on surfaces and loops in protein structures.
- Full Text:
- Date Issued: 2013
Anniversary Bulletin 1943-2013: 70 Years of Struggle... and the Struggle Continues
- Date: 2013
- Subjects: Government, Resistance to -- South Africa , South Africa -- Politics and government , South Africa -- History -- 20th century
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/10948/37365 , vital:34158 , Bulk File 7
- Description: The Bulletin was the official newsletter of the New Unity Movement. It was published about twice a year and contained articles reflecting the organisation's views on resistance to the Apartheid government.
- Full Text: false
- Date Issued: 2013
- Date: 2013
- Subjects: Government, Resistance to -- South Africa , South Africa -- Politics and government , South Africa -- History -- 20th century
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/10948/37365 , vital:34158 , Bulk File 7
- Description: The Bulletin was the official newsletter of the New Unity Movement. It was published about twice a year and contained articles reflecting the organisation's views on resistance to the Apartheid government.
- Full Text: false
- Date Issued: 2013
Applying a student curriculum discourse in higher education teaching and learning
- Mndzebele, Samuel, McKenna, Sioux
- Authors: Mndzebele, Samuel , McKenna, Sioux
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187417 , vital:44633 , xlink:href="https://doi.org/10.1080/18146627.2013.786210"
- Description: Indications of poor quality in students’ written work necessitated the need for deeper investigations aimed at designing and applying appropriate teaching/learning and assessment innovations in the course curriculum. The project-exercise engaged a conceptual-explorative approach through: reviews/investigations; educational diagnosis; design/application of innovations and evaluation processes. In addition to other challenges, diagnosed problems included: students’ ignorance on key curriculum components; imbalance in teaching/learning and assessment tasks engaging all 3-learning domains; less intensiveness of the e-learning mode; and superficial formative feedback. Included a “Student-Curriculum-Discourse” self-tutorial guide, and tasks alignment of the teaching/learning and assessment. Learners’ performance can be improved through a curriculum-discourse self-tutorial exercise, complemented with: intellectual, social, experiential, and emotional structures. Both educators and learners share specific responsibilities in the teaching/learning environment. There is need to expand/probe the theoretical dimension within which the on-line distance education occurs.
- Full Text:
- Date Issued: 2013
- Authors: Mndzebele, Samuel , McKenna, Sioux
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187417 , vital:44633 , xlink:href="https://doi.org/10.1080/18146627.2013.786210"
- Description: Indications of poor quality in students’ written work necessitated the need for deeper investigations aimed at designing and applying appropriate teaching/learning and assessment innovations in the course curriculum. The project-exercise engaged a conceptual-explorative approach through: reviews/investigations; educational diagnosis; design/application of innovations and evaluation processes. In addition to other challenges, diagnosed problems included: students’ ignorance on key curriculum components; imbalance in teaching/learning and assessment tasks engaging all 3-learning domains; less intensiveness of the e-learning mode; and superficial formative feedback. Included a “Student-Curriculum-Discourse” self-tutorial guide, and tasks alignment of the teaching/learning and assessment. Learners’ performance can be improved through a curriculum-discourse self-tutorial exercise, complemented with: intellectual, social, experiential, and emotional structures. Both educators and learners share specific responsibilities in the teaching/learning environment. There is need to expand/probe the theoretical dimension within which the on-line distance education occurs.
- Full Text:
- Date Issued: 2013
Assessment of potential anti-cancer stem cell activity of marine algal compounds using an in vitro mammosphere assay:
- de la Mare, Jo-Anne, Sterrenberg, Jason N, Sukhthankar, Mugdha G, Chiwakata, Maynard T, Beukes, Denzil R, Blatch, Gregory L, Edkins, Adrienne L
- Authors: de la Mare, Jo-Anne , Sterrenberg, Jason N , Sukhthankar, Mugdha G , Chiwakata, Maynard T , Beukes, Denzil R , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165184 , vital:41216 , DOI: 10.1186/1475-2867-13-39
- Description: The cancer stem cell (CSC) theory proposes that tumours arise from and are sustained by a subpopulation of cells with both cancer and stem cell properties. One of the key hallmarks of CSCs is the ability to grow anchorage-independently under serum-free culture conditions resulting in the formation of tumourspheres. It has further been reported that these cells are resistant to traditional chemotherapeutic agents.
- Full Text:
- Date Issued: 2013
- Authors: de la Mare, Jo-Anne , Sterrenberg, Jason N , Sukhthankar, Mugdha G , Chiwakata, Maynard T , Beukes, Denzil R , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165184 , vital:41216 , DOI: 10.1186/1475-2867-13-39
- Description: The cancer stem cell (CSC) theory proposes that tumours arise from and are sustained by a subpopulation of cells with both cancer and stem cell properties. One of the key hallmarks of CSCs is the ability to grow anchorage-independently under serum-free culture conditions resulting in the formation of tumourspheres. It has further been reported that these cells are resistant to traditional chemotherapeutic agents.
- Full Text:
- Date Issued: 2013
Audio Device Representation, Control, and Monitoring Using SNMP
- Eales, Andrew, Foss, Richard
- Authors: Eales, Andrew , Foss, Richard
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426855 , vital:72396 , https://www.aes.org/e-lib/browse.cfm?elib=17012
- Description: The Simple Network Management Protocol (SNMP) is widely used to configure and monitor networked devices. The architecture of complex audio devices can be elegantly represented using SNMP tables. Carefully considered table indexing schemes support a logical device model that can be accessed using standard SNMP commands. This paper examines the use of SNMP tables to represent the architecture of audio devices. A representational scheme that uses table indexes to provide direct-access to context-sensitive SNMP data objects is presented. The monitoring of parameter values and the implementation of connection management using SNMP are also discussed.
- Full Text:
- Date Issued: 2013
- Authors: Eales, Andrew , Foss, Richard
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426855 , vital:72396 , https://www.aes.org/e-lib/browse.cfm?elib=17012
- Description: The Simple Network Management Protocol (SNMP) is widely used to configure and monitor networked devices. The architecture of complex audio devices can be elegantly represented using SNMP tables. Carefully considered table indexing schemes support a logical device model that can be accessed using standard SNMP commands. This paper examines the use of SNMP tables to represent the architecture of audio devices. A representational scheme that uses table indexes to provide direct-access to context-sensitive SNMP data objects is presented. The monitoring of parameter values and the implementation of connection management using SNMP are also discussed.
- Full Text:
- Date Issued: 2013
Automated classification of computer network attacks
- van Heerden, Renier, Leenen, Louise, Irwin, Barry V W
- Authors: van Heerden, Renier , Leenen, Louise , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429622 , vital:72627 , 10.1109/ICASTech.2013.6707510
- Description: In this paper we demonstrate how an automated reasoner, HermiT, is used to classify instances of computer network based attacks in conjunction with a network attack ontology. The ontology describes different types of network attacks through classes and inter-class relationships and has previously been implemented in the Protege ontology editor. Two significant recent instances of network based attacks are presented as individuals in the ontology and correctly classified by the automated reasoner according to the relevant types of attack scenarios depicted in the ontology. The two network attack instances are the Distributed Denial of Service attack on SpamHaus in 2013 and the theft of 42 million Rand ($6.7 million) from South African Postbank in 2012.
- Full Text:
- Date Issued: 2013
- Authors: van Heerden, Renier , Leenen, Louise , Irwin, Barry V W
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429622 , vital:72627 , 10.1109/ICASTech.2013.6707510
- Description: In this paper we demonstrate how an automated reasoner, HermiT, is used to classify instances of computer network based attacks in conjunction with a network attack ontology. The ontology describes different types of network attacks through classes and inter-class relationships and has previously been implemented in the Protege ontology editor. Two significant recent instances of network based attacks are presented as individuals in the ontology and correctly classified by the automated reasoner according to the relevant types of attack scenarios depicted in the ontology. The two network attack instances are the Distributed Denial of Service attack on SpamHaus in 2013 and the theft of 42 million Rand ($6.7 million) from South African Postbank in 2012.
- Full Text:
- Date Issued: 2013
Axial coordination of zinc and silicon phthalocyanines to silver and gold nanoparticles: an investigation of their photophysicochemical and antimicrobial behavior
- Masilela, Nkosiphile, Antunes, Edith M, Nyokong, Tebello
- Authors: Masilela, Nkosiphile , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241818 , vital:50972 , xlink:href="https://doi.org/10.1142/S1088424613500016"
- Description: This work reports on the axial coordination of zinc phthalocyanine and bis-(1,6-hexanedithiol) silicon phthalocyanine to silver and gold nanoparticles. Red shifting of absorption spectra of the phthalocyanine complexes was observed after conjugation with the nanoparticles. An improvement in the photophysicochemical behavior and antimicrobial activity was achieved in the presence of metal nanoparticles for both complexes. A decrease in triplet lifetimes was observed for all the phthalocyanine metal nanoparticle conjugates. The Zn phthalocyanine complex gave the highest triplet and singlet oxygen quantum yield in the presence of gold nanoparticles. On the other hand, the bacterial inhibition was found to be best for the Si phthalocyanine derivative in the presence of nanoparticles compared to the Zn phthalocyanine counterpart. The highest antimicrobial activity was achieved for both conjugates against B. subtilis compared to S. aureaus both in the dark and under illumination with light.
- Full Text:
- Date Issued: 2013
- Authors: Masilela, Nkosiphile , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241818 , vital:50972 , xlink:href="https://doi.org/10.1142/S1088424613500016"
- Description: This work reports on the axial coordination of zinc phthalocyanine and bis-(1,6-hexanedithiol) silicon phthalocyanine to silver and gold nanoparticles. Red shifting of absorption spectra of the phthalocyanine complexes was observed after conjugation with the nanoparticles. An improvement in the photophysicochemical behavior and antimicrobial activity was achieved in the presence of metal nanoparticles for both complexes. A decrease in triplet lifetimes was observed for all the phthalocyanine metal nanoparticle conjugates. The Zn phthalocyanine complex gave the highest triplet and singlet oxygen quantum yield in the presence of gold nanoparticles. On the other hand, the bacterial inhibition was found to be best for the Si phthalocyanine derivative in the presence of nanoparticles compared to the Zn phthalocyanine counterpart. The highest antimicrobial activity was achieved for both conjugates against B. subtilis compared to S. aureaus both in the dark and under illumination with light.
- Full Text:
- Date Issued: 2013
Behavioural observations of the common octopus Octopus vulgaris in Baía dos Tigres, southern Angola
- de Beer, Chénelle L, Potts, Warren M
- Authors: de Beer, Chénelle L , Potts, Warren M
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123233 , vital:35419 , https://doi.org/10.2989/1814232X.2013.847496
- Description: The common octopus Octopus vulgaris (Cuvier 1797) is a shallow-water cephalopod species that inhabits coastal rocky areas or reefs. It is the most studied and widely distributed species in its genus. This species has a short lifespan and a rapid growth rate of over 5% of body weight per day (García and Valverde 2006, Ibáñez and Keyl 2010). It is semelparous, with females laying large strings of eggs that they attach to the substrata in their dens (Hernández- García et al. 2002). There is a paucity of information on the preferred habitat and behaviour of O. vulgaris in its natural environment (Anderson 1997, Meisel et al. 2006). The species has been classified as highly mobile, yet resident individuals may exhibit high levels of territoriality. Its mobility allows it to move efficiently between a wide range of suitable habitats (Katsanevakis and Verriopoulos 2004). Octopus make use of both tactile and visual senses to forage, feed and seek suitable shelter (Forsythe and Hanlon 1997, Carvalho and Sousa Reis 2003, Rodríguez-Rúa et al. 2005). They are active feeders that seek out prey such as crustaceans, sessile molluscs and small fish (Forsythe and Hanlon 1997, Boyle and Rodhouse 2005), as well as their smaller conspecifics (Ibáñez and Keyl 2010). The majority of behavioural ecology studies on octopus have been on captive individuals. However, the activity patterns (Mather 1988), foraging strategies and aspects of the movement behaviour (Mather and O’Dor 1991) of juvenile O. vulgaris in the wild were described for an exploited population in Bermuda. Because intertidal octopus stocks are exploited by recreational, subsistence and artisanal fisheries (e.g. Oosthuizen and Smale 2003, Sauer et al. 2011), there are few opportunities to study the behavioural ecology of unexploited populations. An opportunity arose to study various behavioural patterns in an unexploited population in Baía dos Tigres, a large (~200 km2) coastal embayment situated on an isolated stretch of the southern Angolan coast (Figure 1). This study provides information on the population size structure, aspects of the movement behaviour, activity patterns and foraging strategies of O. vulgaris in this largely unstudied coastal embayment.
- Full Text:
- Date Issued: 2013
- Authors: de Beer, Chénelle L , Potts, Warren M
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123233 , vital:35419 , https://doi.org/10.2989/1814232X.2013.847496
- Description: The common octopus Octopus vulgaris (Cuvier 1797) is a shallow-water cephalopod species that inhabits coastal rocky areas or reefs. It is the most studied and widely distributed species in its genus. This species has a short lifespan and a rapid growth rate of over 5% of body weight per day (García and Valverde 2006, Ibáñez and Keyl 2010). It is semelparous, with females laying large strings of eggs that they attach to the substrata in their dens (Hernández- García et al. 2002). There is a paucity of information on the preferred habitat and behaviour of O. vulgaris in its natural environment (Anderson 1997, Meisel et al. 2006). The species has been classified as highly mobile, yet resident individuals may exhibit high levels of territoriality. Its mobility allows it to move efficiently between a wide range of suitable habitats (Katsanevakis and Verriopoulos 2004). Octopus make use of both tactile and visual senses to forage, feed and seek suitable shelter (Forsythe and Hanlon 1997, Carvalho and Sousa Reis 2003, Rodríguez-Rúa et al. 2005). They are active feeders that seek out prey such as crustaceans, sessile molluscs and small fish (Forsythe and Hanlon 1997, Boyle and Rodhouse 2005), as well as their smaller conspecifics (Ibáñez and Keyl 2010). The majority of behavioural ecology studies on octopus have been on captive individuals. However, the activity patterns (Mather 1988), foraging strategies and aspects of the movement behaviour (Mather and O’Dor 1991) of juvenile O. vulgaris in the wild were described for an exploited population in Bermuda. Because intertidal octopus stocks are exploited by recreational, subsistence and artisanal fisheries (e.g. Oosthuizen and Smale 2003, Sauer et al. 2011), there are few opportunities to study the behavioural ecology of unexploited populations. An opportunity arose to study various behavioural patterns in an unexploited population in Baía dos Tigres, a large (~200 km2) coastal embayment situated on an isolated stretch of the southern Angolan coast (Figure 1). This study provides information on the population size structure, aspects of the movement behaviour, activity patterns and foraging strategies of O. vulgaris in this largely unstudied coastal embayment.
- Full Text:
- Date Issued: 2013