Celebrating libraries in 20 years of democracy : an overview of library and information services in South Africa
- Authors: Satgoor, Ujala
- Date: 2015
- Subjects: Libraries , Library administration -- South Africa , Information services -- South Africa , Public libraries -- South Africa , Library science -- South Africa
- Language: English
- Type: Article
- Identifier: vital:6997 , http://hdl.handle.net/10962/d1019841 , ISSN ISSN: 0340-0352 , http://journals.sagepub.com/doi/10.1177/0340035215585100
- Description: Since the establishment of the first public library in 1818, the South African library and information services landscape has also been a reflection of the socio-political order and developments in the country. This article presents an historical perspective as well as an overview of libraries in South Africa since 1994, the context within which libraries function, library governance and legislative framework, government funding for redress, library technologies, library and information services education and the professional association. The article further highlights the importance of libraries in meeting the goals of the national development agenda towards entrenching a strong democracy and an educated and informed nation , Original publication is available at: http://dx.doi.org/10.1177/0340035215585100
- Full Text:
- Date Issued: 2015
- Authors: Satgoor, Ujala
- Date: 2015
- Subjects: Libraries , Library administration -- South Africa , Information services -- South Africa , Public libraries -- South Africa , Library science -- South Africa
- Language: English
- Type: Article
- Identifier: vital:6997 , http://hdl.handle.net/10962/d1019841 , ISSN ISSN: 0340-0352 , http://journals.sagepub.com/doi/10.1177/0340035215585100
- Description: Since the establishment of the first public library in 1818, the South African library and information services landscape has also been a reflection of the socio-political order and developments in the country. This article presents an historical perspective as well as an overview of libraries in South Africa since 1994, the context within which libraries function, library governance and legislative framework, government funding for redress, library technologies, library and information services education and the professional association. The article further highlights the importance of libraries in meeting the goals of the national development agenda towards entrenching a strong democracy and an educated and informed nation , Original publication is available at: http://dx.doi.org/10.1177/0340035215585100
- Full Text:
- Date Issued: 2015
Stigma resistance in online child free communities : the limitations of choice rhetoric
- Morison, Tracy, Macleod, Catriona I, Lynch, Ingrid, Mijas, Magda, Shivakumar, Seemanthini T
- Authors: Morison, Tracy , Macleod, Catriona I , Lynch, Ingrid , Mijas, Magda , Shivakumar, Seemanthini T
- Date: 2015
- Language: English
- Type: Article
- Identifier: vital:6311 , http://hdl.handle.net/10962/d1019799 , http://journals.sagepub.com/doi/10.1177/0361684315603657
- Description: People who are voluntarily childless, or ‘‘childfree,’’ face considerable stigma. Researchers have begun to explore how these individuals respond to stigma, usually focusing on interpersonal stigma management strategies. We explored participants’ responses to stigma in a way that is cognisant of broader social norms and gender power relations. Using a feminist discursive psychology framework, we analysed women’s and men’s computer-assisted communication about their childfree status. Our analysis draws attention to ‘‘identity work’’ in the context of stigma. We show how the strategic use of ‘‘choice’’ rhetoric allowed participants to avoid stigmatised identities and was used in two contradictory ways. On the one hand, participants drew on a ‘‘childfree-by-choice script,’’ which enabled them to hold a positive identity of themselves as autonomous, rational, and responsible decision makers. On the other hand, they mobilised a ‘‘disavowal of choice script’’ that allowed a person who is unable to choose childlessness (for various reasons) to hold a blameless identity regarding deviation from the norm of parenthood. We demonstrate how choice rhetoric allowed participants to resist stigma and challenge pronatalism to some extent; we discuss the political potential of these scripts for reproductive freedom.
- Full Text:
- Date Issued: 2015
- Authors: Morison, Tracy , Macleod, Catriona I , Lynch, Ingrid , Mijas, Magda , Shivakumar, Seemanthini T
- Date: 2015
- Language: English
- Type: Article
- Identifier: vital:6311 , http://hdl.handle.net/10962/d1019799 , http://journals.sagepub.com/doi/10.1177/0361684315603657
- Description: People who are voluntarily childless, or ‘‘childfree,’’ face considerable stigma. Researchers have begun to explore how these individuals respond to stigma, usually focusing on interpersonal stigma management strategies. We explored participants’ responses to stigma in a way that is cognisant of broader social norms and gender power relations. Using a feminist discursive psychology framework, we analysed women’s and men’s computer-assisted communication about their childfree status. Our analysis draws attention to ‘‘identity work’’ in the context of stigma. We show how the strategic use of ‘‘choice’’ rhetoric allowed participants to avoid stigmatised identities and was used in two contradictory ways. On the one hand, participants drew on a ‘‘childfree-by-choice script,’’ which enabled them to hold a positive identity of themselves as autonomous, rational, and responsible decision makers. On the other hand, they mobilised a ‘‘disavowal of choice script’’ that allowed a person who is unable to choose childlessness (for various reasons) to hold a blameless identity regarding deviation from the norm of parenthood. We demonstrate how choice rhetoric allowed participants to resist stigma and challenge pronatalism to some extent; we discuss the political potential of these scripts for reproductive freedom.
- Full Text:
- Date Issued: 2015
The Evil of sluits : a re-assessment of soil erosion in the Karoo of South Africa as portrayed in century-old sources
- Authors: Rowntree, Kate M
- Date: 2013
- Language: English
- Type: Article
- Identifier: vital:6725 , http://hdl.handle.net/10962/d1006803
- Description: Deep, linear gullies are a common feature of the present landscape of the Karoo of South Africa, where they were known locally in the early twentieth century as ‘sluits’. Recent research has shown that many of these features are now stable and are no longer significant sediment sources, although they are efficient connectors in the landscape. Because most of the gully networks predate the first aerial photographs, little is known in the scientific literature about the timing of their formation. One secondary source, however, throws interesting light on the origin of these features, and the early response by landowners to their rehabilitation. The Agricultural Journal of the Cape of Good Hope at the turn of the Twentieth Century carried a number of articles by farmers and agricultural officers concerning the "evil of sluits". The authors gave accounts of widespread incision of valley bottoms by deep, wide gullies. Many of these gullies had been in existence for some thirty years but apparently had formed within living memory. A number of attempts to prevent further erosion had been put in place at the time of writing. This paper presents a review of land degradation, specifically gully erosion, and rehabilitation recommendations as given by authors writing in this journal. It reflects on the findings in the context of assessing land degradation processes through the local knowledge portrayed in the journal.
- Full Text:
- Date Issued: 2013
- Authors: Rowntree, Kate M
- Date: 2013
- Language: English
- Type: Article
- Identifier: vital:6725 , http://hdl.handle.net/10962/d1006803
- Description: Deep, linear gullies are a common feature of the present landscape of the Karoo of South Africa, where they were known locally in the early twentieth century as ‘sluits’. Recent research has shown that many of these features are now stable and are no longer significant sediment sources, although they are efficient connectors in the landscape. Because most of the gully networks predate the first aerial photographs, little is known in the scientific literature about the timing of their formation. One secondary source, however, throws interesting light on the origin of these features, and the early response by landowners to their rehabilitation. The Agricultural Journal of the Cape of Good Hope at the turn of the Twentieth Century carried a number of articles by farmers and agricultural officers concerning the "evil of sluits". The authors gave accounts of widespread incision of valley bottoms by deep, wide gullies. Many of these gullies had been in existence for some thirty years but apparently had formed within living memory. A number of attempts to prevent further erosion had been put in place at the time of writing. This paper presents a review of land degradation, specifically gully erosion, and rehabilitation recommendations as given by authors writing in this journal. It reflects on the findings in the context of assessing land degradation processes through the local knowledge portrayed in the journal.
- Full Text:
- Date Issued: 2013
Dynamics of a lattice Universe : the dust approximation in cosmology
- Bruneton, J-P, Larena, Julien
- Authors: Bruneton, J-P , Larena, Julien
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6789 , http://hdl.handle.net/10962/d1006941
- Description: We find a solution to Einstein field equations for a regular toroidal lattice of size L with equal masses M at the centre of each cell; this solution is exact at order M/L. Such a solution is convenient to study the dynamics of an assembly of galaxy-like objects. We find that the solution is expanding (or contracting) in exactly the same way as the solution of a Friedman–Lemaître–Robertson–Walker Universe with dust having the same average density as our model. This points towards the absence of backreaction in a Universe filled with an infinite number of objects, and this validates the fluid approximation, as far as dynamics is concerned, and at the level of approximation considered in this work.
- Full Text:
- Date Issued: 2012
- Authors: Bruneton, J-P , Larena, Julien
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6789 , http://hdl.handle.net/10962/d1006941
- Description: We find a solution to Einstein field equations for a regular toroidal lattice of size L with equal masses M at the centre of each cell; this solution is exact at order M/L. Such a solution is convenient to study the dynamics of an assembly of galaxy-like objects. We find that the solution is expanding (or contracting) in exactly the same way as the solution of a Friedman–Lemaître–Robertson–Walker Universe with dust having the same average density as our model. This points towards the absence of backreaction in a Universe filled with an infinite number of objects, and this validates the fluid approximation, as far as dynamics is concerned, and at the level of approximation considered in this work.
- Full Text:
- Date Issued: 2012
Treating complex post-traumatic stress disorder following childhood neglect, sexual abuse and revictimisation : interpretative reflections on the case of Khuselwa
- Padmanabhanunni, A, Edwards, David J A
- Authors: Padmanabhanunni, A , Edwards, David J A
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6233 , http://hdl.handle.net/10962/d1007783
- Description: This paper describes the psychological assessment and treatment process with Khuselwa, a South African adolescent survivor of multiple sexual traumas presenting with complex post-traumatic stress disorder (PTSD). The paper identifies some of the common barriers encountered by practitioners in delivering treatments in local contexts and highlights the role of external safety and stability and social support in providing a vehicle for change and a basis for overcoming the psychological handicaps reinforced by repeated and multiple traumas and chronic neglect.
- Full Text:
- Date Issued: 2012
- Authors: Padmanabhanunni, A , Edwards, David J A
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6233 , http://hdl.handle.net/10962/d1007783
- Description: This paper describes the psychological assessment and treatment process with Khuselwa, a South African adolescent survivor of multiple sexual traumas presenting with complex post-traumatic stress disorder (PTSD). The paper identifies some of the common barriers encountered by practitioners in delivering treatments in local contexts and highlights the role of external safety and stability and social support in providing a vehicle for change and a basis for overcoming the psychological handicaps reinforced by repeated and multiple traumas and chronic neglect.
- Full Text:
- Date Issued: 2012
The identity of Albuca caudata Jacq. (Hyacinthaceae) and a description of a new related species : A. bakeri
- Martinez-Azorin, Mario, Cresbo, Manuel B, Dold, Anthony P, Barker, Nigel P
- Authors: Martinez-Azorin, Mario , Cresbo, Manuel B , Dold, Anthony P , Barker, Nigel P
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6528 , http://hdl.handle.net/10962/d1005969
- Description: The name Albuca caudata Jacq. has been widely misunderstood or even ignored since its description in 1791. After studying herbarium specimens and living populations in South Africa, plants fitting Jacquin´s concept of that species are found to be widely distributed in the Eastern Cape, mainly in the Albany centre of Endemism. Furthermore, some divergent specimens matching Baker´s concept of Albuca caudata are described as a new related species: Albuca bakeri. Data on typification, morphology, ecology, and distribution are reported for both taxa. Affinities and divergences with other close allies are also discussed.
- Full Text:
- Date Issued: 2011
- Authors: Martinez-Azorin, Mario , Cresbo, Manuel B , Dold, Anthony P , Barker, Nigel P
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6528 , http://hdl.handle.net/10962/d1005969
- Description: The name Albuca caudata Jacq. has been widely misunderstood or even ignored since its description in 1791. After studying herbarium specimens and living populations in South Africa, plants fitting Jacquin´s concept of that species are found to be widely distributed in the Eastern Cape, mainly in the Albany centre of Endemism. Furthermore, some divergent specimens matching Baker´s concept of Albuca caudata are described as a new related species: Albuca bakeri. Data on typification, morphology, ecology, and distribution are reported for both taxa. Affinities and divergences with other close allies are also discussed.
- Full Text:
- Date Issued: 2011
The determination of acetaminophen using a carbon nanotube: graphite-based electrode
- Moghaddam, Abdolmajid B, Mohammadi, Ali, Mohammadi, Somaye, Rayeji, Danyal, Dinarvand, Rassoul, Baghi, Mansoureh, Walker, Roderick B
- Authors: Moghaddam, Abdolmajid B , Mohammadi, Ali , Mohammadi, Somaye , Rayeji, Danyal , Dinarvand, Rassoul , Baghi, Mansoureh , Walker, Roderick B
- Date: 2010
- Language: English
- Type: Article , text
- Identifier: vital:6414 , http://hdl.handle.net/10962/d1006509
- Description: The oxidation of acetaminophen was studied at a glassy carbon electrode modified with multi-walled carbon nanotubes and a graphite paste. Cyclic voltammety, differential pulse voltammetry and square wave voltammetry at various pH values, scan rates, and the effect of the ratio of nanotubes to graphite were investigated in order to optimize the parameters for the determination of acetaminophen. Square wave voltammetry is the most appropriate technique in giving a characteristic peak at 0.52 V at pH 5. The porous nanostructure of the electrode improves the surface area which results in an increase in the peak current. The voltammetric response is linear in the range between 75 and 2000 ng.mL−1, with standard deviations between 0.25 and 7.8%, and a limit of detection of 25 ng.mL−1. The method has been successfully applied to the analysis of acetaminophen in tablets and biological fluids.
- Full Text:
- Date Issued: 2010
- Authors: Moghaddam, Abdolmajid B , Mohammadi, Ali , Mohammadi, Somaye , Rayeji, Danyal , Dinarvand, Rassoul , Baghi, Mansoureh , Walker, Roderick B
- Date: 2010
- Language: English
- Type: Article , text
- Identifier: vital:6414 , http://hdl.handle.net/10962/d1006509
- Description: The oxidation of acetaminophen was studied at a glassy carbon electrode modified with multi-walled carbon nanotubes and a graphite paste. Cyclic voltammety, differential pulse voltammetry and square wave voltammetry at various pH values, scan rates, and the effect of the ratio of nanotubes to graphite were investigated in order to optimize the parameters for the determination of acetaminophen. Square wave voltammetry is the most appropriate technique in giving a characteristic peak at 0.52 V at pH 5. The porous nanostructure of the electrode improves the surface area which results in an increase in the peak current. The voltammetric response is linear in the range between 75 and 2000 ng.mL−1, with standard deviations between 0.25 and 7.8%, and a limit of detection of 25 ng.mL−1. The method has been successfully applied to the analysis of acetaminophen in tablets and biological fluids.
- Full Text:
- Date Issued: 2010
A recurrent neural network approach to quantitatively studying solar wind effects on TEC derived from GPS; preliminary results
- Habarulema, John B, McKinnell, Lee-Anne, Opperman, Ben D L
- Authors: Habarulema, John B , McKinnell, Lee-Anne , Opperman, Ben D L
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6813 , http://hdl.handle.net/10962/d1004323
- Description: This paper attempts to describe the search for the parameter(s) to represent solar wind effects in Global Positioning System total electron content (GPS TEC) modelling using the technique of neural networks (NNs). A study is carried out by including solar wind velocity (Vsw), proton number density (Np) and the Bz component of the interplanetary magnetic field (IMF Bz) obtained from the Advanced Composition Explorer (ACE) satellite as separate inputs to the NN each along with day number of the year (DN), hour (HR), a 4-month running mean of the daily sunspot number (R4) and the running mean of the previous eight 3-hourly magnetic A index values (A8). Hourly GPS TEC values derived from a dual frequency receiver located at Sutherland (32.38° S, 20.81° E), South Africa for 8 years (2000–2007) have been used to train the Elman neural network (ENN) and the result has been used to predict TEC variations for a GPS station located at Cape Town (33.95° S, 18.47° E). Quantitative results indicate that each of the parameters considered may have some degree of influence on GPS TEC at certain periods although a decrease in prediction accuracy is also observed for some parameters for different days and seasons. It is also evident that there is still a difficulty in predicting TEC values during disturbed conditions. The improvements and degradation in prediction accuracies are both close to the benchmark values which lends weight to the belief that diurnal, seasonal, solar and magnetic variabilities may be the major determinants of TEC variability.
- Full Text:
- Date Issued: 2009
- Authors: Habarulema, John B , McKinnell, Lee-Anne , Opperman, Ben D L
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6813 , http://hdl.handle.net/10962/d1004323
- Description: This paper attempts to describe the search for the parameter(s) to represent solar wind effects in Global Positioning System total electron content (GPS TEC) modelling using the technique of neural networks (NNs). A study is carried out by including solar wind velocity (Vsw), proton number density (Np) and the Bz component of the interplanetary magnetic field (IMF Bz) obtained from the Advanced Composition Explorer (ACE) satellite as separate inputs to the NN each along with day number of the year (DN), hour (HR), a 4-month running mean of the daily sunspot number (R4) and the running mean of the previous eight 3-hourly magnetic A index values (A8). Hourly GPS TEC values derived from a dual frequency receiver located at Sutherland (32.38° S, 20.81° E), South Africa for 8 years (2000–2007) have been used to train the Elman neural network (ENN) and the result has been used to predict TEC variations for a GPS station located at Cape Town (33.95° S, 18.47° E). Quantitative results indicate that each of the parameters considered may have some degree of influence on GPS TEC at certain periods although a decrease in prediction accuracy is also observed for some parameters for different days and seasons. It is also evident that there is still a difficulty in predicting TEC values during disturbed conditions. The improvements and degradation in prediction accuracies are both close to the benchmark values which lends weight to the belief that diurnal, seasonal, solar and magnetic variabilities may be the major determinants of TEC variability.
- Full Text:
- Date Issued: 2009
Efficacy of solar power units for small-scale businesses in a remote rural area, South Africa
- Hajat, A, Banks, D, Aiken, R, Shackleton, Charlie M
- Authors: Hajat, A , Banks, D , Aiken, R , Shackleton, Charlie M
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6636 , http://hdl.handle.net/10962/d1006860
- Description: Much work has considered the practicalities and affordability of solar systems for domestic energy supplies in remote rural areas. There is less understanding of its utility for small-scale business enterprises in such areas. We examined the patterns of use of two 12 V and one 24 V systems for small-scale enterprises housed in transportable containers. Monitoring of load shed and top of charge indicated that the 12 V systems were inadequate to meet the requirements of the enterprises. The 24 V operation performed a lot better. Despite some technical limitations the system offered a number of social, economic and environmental positives; primarily the offering of business products not otherwise available in the area, incomes to the entrepreneurs and greater connectivity with regional centres through office services such as cell-phone charging and faxing. Customers of the small-scale enterprises felt that their presence in the area saved them some money because they no longer had to travel as frequently to regional urban centres.
- Full Text:
- Date Issued: 2009
- Authors: Hajat, A , Banks, D , Aiken, R , Shackleton, Charlie M
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6636 , http://hdl.handle.net/10962/d1006860
- Description: Much work has considered the practicalities and affordability of solar systems for domestic energy supplies in remote rural areas. There is less understanding of its utility for small-scale business enterprises in such areas. We examined the patterns of use of two 12 V and one 24 V systems for small-scale enterprises housed in transportable containers. Monitoring of load shed and top of charge indicated that the 12 V systems were inadequate to meet the requirements of the enterprises. The 24 V operation performed a lot better. Despite some technical limitations the system offered a number of social, economic and environmental positives; primarily the offering of business products not otherwise available in the area, incomes to the entrepreneurs and greater connectivity with regional centres through office services such as cell-phone charging and faxing. Customers of the small-scale enterprises felt that their presence in the area saved them some money because they no longer had to travel as frequently to regional urban centres.
- Full Text:
- Date Issued: 2009
Seeing is natural, but viewing is not: teaching visual literacy in a rural classroom
- Mbelani, Madeyandile, Murray, Sarah R
- Authors: Mbelani, Madeyandile , Murray, Sarah R
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:7022 , http://hdl.handle.net/10962/d1007203
- Description: This paper reports on a collaborative action research case study into Grade 10 teaching and learning of visual literacy in a rural high school into the Eastern Cape, South Africa. Visual literacy is a new aspect that has been incorporated in English First Additional Language National Curriculum Statement (Grade 10-12), which has been implemented in Grade 10 from 2006. With the aim of gaining knowledge and improving performance in visual literacy, I designed a unit of lessons, which exposed learners to visual grammar and visual texts and I collected data around the implementation of the lesson unit as evidenced by journal writing, interviews and non-participant observation. The data revealed that visual literacy could be taught meaningfully in a rural high school as the learners could identify, cut, paste and critically discuss elements of visual language and they finally designed their own advertisements in groups. However, the following factors emerged as hindrances to the successful teaching of visual literacy in this case: lack of resources; learners' lack of a foundation in visual literacy from Grades 7-9; and problems revolving around time management and pacing.
- Full Text:
- Date Issued: 2009
- Authors: Mbelani, Madeyandile , Murray, Sarah R
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:7022 , http://hdl.handle.net/10962/d1007203
- Description: This paper reports on a collaborative action research case study into Grade 10 teaching and learning of visual literacy in a rural high school into the Eastern Cape, South Africa. Visual literacy is a new aspect that has been incorporated in English First Additional Language National Curriculum Statement (Grade 10-12), which has been implemented in Grade 10 from 2006. With the aim of gaining knowledge and improving performance in visual literacy, I designed a unit of lessons, which exposed learners to visual grammar and visual texts and I collected data around the implementation of the lesson unit as evidenced by journal writing, interviews and non-participant observation. The data revealed that visual literacy could be taught meaningfully in a rural high school as the learners could identify, cut, paste and critically discuss elements of visual language and they finally designed their own advertisements in groups. However, the following factors emerged as hindrances to the successful teaching of visual literacy in this case: lack of resources; learners' lack of a foundation in visual literacy from Grades 7-9; and problems revolving around time management and pacing.
- Full Text:
- Date Issued: 2009
Temporal and spatial variability in stable isotope ratios of SPM link to local hydrography and longer term SPM averages suggest heavy dependence of mussels on nearshore production
- Hill, Jaclyn M, McQuaid, Christopher D, Kaehler, Sven
- Authors: Hill, Jaclyn M , McQuaid, Christopher D , Kaehler, Sven
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6969 , http://hdl.handle.net/10962/d1012034
- Description: Temporal changes in hydrography affect suspended particulate matter (SPM) composition and distribution in coastal systems, potentially influencing the diets of suspension feeders. Temporal variation in SPM and in the diet of the mussel Perna perna, were investigated using stable isotope analysis. The δ13C and δ15 N ratios of SPM, mussels and macroalgae were determined monthly, with SPM samples collected along a 10 km onshore–offshore transect, over 14 months at Kenton-on-Sea, on the south coast of South Africa. Clear nearshore (0 km) to offshore (10 km) carbon depletion gradients were seen in SPM during all months and extended for 50 km offshore on one occasion. Carbon enrichment of coastal SPM in winter (June–August 2004 and May 2005) indicated temporal changes in the nearshore detrital pool, presumably reflecting changes in macroalgal detritus, linked to local changes in coastal hydrography and algal seasonality. Nitrogen patterns were less clear, with SPM enrichment seen between July and October 2004 from 0 to 10 km. Nearshore SPM demonstrated cyclical patterns in carbon over 24-h periods that correlated closely with tidal cycles and mussel carbon signatures, sampled monthly, demonstrated fluctuations that could not be correlated to seasonal or monthly changes in SPM. Macroalgae showed extreme variability in isotopic signatures, with no discernable patterns. IsoSource mixing models indicated over 50% reliance of mussel tissue on nearshore carbon, highlighting the importance of nearshore SPM in mussel diet. Overall, carbon variation in SPM at both large and small temporal scales can be related to hydrographic processes, but is masked in mussels by long-term isotope integration.
- Full Text:
- Date Issued: 2008
- Authors: Hill, Jaclyn M , McQuaid, Christopher D , Kaehler, Sven
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6969 , http://hdl.handle.net/10962/d1012034
- Description: Temporal changes in hydrography affect suspended particulate matter (SPM) composition and distribution in coastal systems, potentially influencing the diets of suspension feeders. Temporal variation in SPM and in the diet of the mussel Perna perna, were investigated using stable isotope analysis. The δ13C and δ15 N ratios of SPM, mussels and macroalgae were determined monthly, with SPM samples collected along a 10 km onshore–offshore transect, over 14 months at Kenton-on-Sea, on the south coast of South Africa. Clear nearshore (0 km) to offshore (10 km) carbon depletion gradients were seen in SPM during all months and extended for 50 km offshore on one occasion. Carbon enrichment of coastal SPM in winter (June–August 2004 and May 2005) indicated temporal changes in the nearshore detrital pool, presumably reflecting changes in macroalgal detritus, linked to local changes in coastal hydrography and algal seasonality. Nitrogen patterns were less clear, with SPM enrichment seen between July and October 2004 from 0 to 10 km. Nearshore SPM demonstrated cyclical patterns in carbon over 24-h periods that correlated closely with tidal cycles and mussel carbon signatures, sampled monthly, demonstrated fluctuations that could not be correlated to seasonal or monthly changes in SPM. Macroalgae showed extreme variability in isotopic signatures, with no discernable patterns. IsoSource mixing models indicated over 50% reliance of mussel tissue on nearshore carbon, highlighting the importance of nearshore SPM in mussel diet. Overall, carbon variation in SPM at both large and small temporal scales can be related to hydrographic processes, but is masked in mussels by long-term isotope integration.
- Full Text:
- Date Issued: 2008
Winds of change in teachers’ classroom assessment practice: a self-critical reflection on the teaching and learning of visual literacy in a rural Eastern Cape High School
- Authors: Mbelani, Madeyandile
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:7021 , http://hdl.handle.net/10962/d1007201
- Description: The year 2006 saw the implementation of a new curriculum for teaching English First Additional Language (FAL) in grades 10-12 in South African high schools. The curriculum includes the teaching and assessment of visual literacy – a challenge for teachers whose apartheid-era teacher education did not address visual literacy at all. The article is a self-critical reflection on my attempts to teach and assess a unit on visual literacy in a Grade 10 class in a rural high school in the Eastern Cape province of South Africa.
- Full Text:
- Date Issued: 2008
- Authors: Mbelani, Madeyandile
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:7021 , http://hdl.handle.net/10962/d1007201
- Description: The year 2006 saw the implementation of a new curriculum for teaching English First Additional Language (FAL) in grades 10-12 in South African high schools. The curriculum includes the teaching and assessment of visual literacy – a challenge for teachers whose apartheid-era teacher education did not address visual literacy at all. The article is a self-critical reflection on my attempts to teach and assess a unit on visual literacy in a Grade 10 class in a rural high school in the Eastern Cape province of South Africa.
- Full Text:
- Date Issued: 2008
Electrochemical characterisation of tetra- and octa-substituted oxo(phthalocyaninato)titanium(IV) complexes
- Tau, Prudence Lerato, Nyokong, Tebello
- Authors: Tau, Prudence Lerato , Nyokong, Tebello
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6598 , http://hdl.handle.net/10962/d1004347
- Description: The synthesis and electrochemical characterisation of the following oxotitanium tetra-substituted phthalocyanines are reported: 1,(4)-(tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (5a); 1,(4)- {tetrakis[4-(benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (5b); 2,(3)- (tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (6a) and 2,(3)-{tetrakis[4- (benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (6b). The electrochemical characterisation of complexes octa-substituted with 4-(benzyloxy)phenoxy (9b), phenoxy (9c) and tert -butylphenoxy (9d) groups is also reported. The cyclic voltammograms of the complexes exhibit reversible couples I–III and couple IV is quasi-reversible for complexes 5a, 5b, 6a and 6b. The first two reductions are metal-based processes, confirmed by spectroelectrochemistry to be due to Ti IV Pc 2 − /Ti III Pc 2 − and Ti III Pc 2 − /Ti II Pc 2 − redox processes and the last two reductions are ring-based processes due to Ti II Pc 2 − /Ti II Pc 3 − and Ti II Pc 3 − /Ti II Pc 4 − . Chronocoulometry confirmed a one-electron transfer at each reduction step. The electrochemistry of the above complexes is also compared to the previously reported 5c, 5d, 6c and 6d.
- Full Text:
- Date Issued: 2007
- Authors: Tau, Prudence Lerato , Nyokong, Tebello
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6598 , http://hdl.handle.net/10962/d1004347
- Description: The synthesis and electrochemical characterisation of the following oxotitanium tetra-substituted phthalocyanines are reported: 1,(4)-(tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (5a); 1,(4)- {tetrakis[4-(benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (5b); 2,(3)- (tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (6a) and 2,(3)-{tetrakis[4- (benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (6b). The electrochemical characterisation of complexes octa-substituted with 4-(benzyloxy)phenoxy (9b), phenoxy (9c) and tert -butylphenoxy (9d) groups is also reported. The cyclic voltammograms of the complexes exhibit reversible couples I–III and couple IV is quasi-reversible for complexes 5a, 5b, 6a and 6b. The first two reductions are metal-based processes, confirmed by spectroelectrochemistry to be due to Ti IV Pc 2 − /Ti III Pc 2 − and Ti III Pc 2 − /Ti II Pc 2 − redox processes and the last two reductions are ring-based processes due to Ti II Pc 2 − /Ti II Pc 3 − and Ti II Pc 3 − /Ti II Pc 4 − . Chronocoulometry confirmed a one-electron transfer at each reduction step. The electrochemistry of the above complexes is also compared to the previously reported 5c, 5d, 6c and 6d.
- Full Text:
- Date Issued: 2007
Physical implications of prolonged sitting in a confined posture - a literature review
- Todd, Andrew I, Bennett, Anthea I, Christie, Candice J
- Authors: Todd, Andrew I , Bennett, Anthea I , Christie, Candice J
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6756 , http://hdl.handle.net/10962/d1009458
- Description: The main purpose of this review article was to highlight some of the physical consequences of sitting for prolonged periods in a confined setting. More specifically, the review relates this research to call centre work and where applicable comments on the limited literature relating specifically to ergonomics research within call centre settings. In particular the article explores the biomechanical stresses placed on the musculoskeletal system during prolonged sitting at a workstation, and the physiological consequences thereof. The paper then provides possible solutions to reduce the physical strain placed on these workers by looking at workstation design and work organisation emphasizing worker education and the promotion of worker well being.
- Full Text:
- Date Issued: 2007
- Authors: Todd, Andrew I , Bennett, Anthea I , Christie, Candice J
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6756 , http://hdl.handle.net/10962/d1009458
- Description: The main purpose of this review article was to highlight some of the physical consequences of sitting for prolonged periods in a confined setting. More specifically, the review relates this research to call centre work and where applicable comments on the limited literature relating specifically to ergonomics research within call centre settings. In particular the article explores the biomechanical stresses placed on the musculoskeletal system during prolonged sitting at a workstation, and the physiological consequences thereof. The paper then provides possible solutions to reduce the physical strain placed on these workers by looking at workstation design and work organisation emphasizing worker education and the promotion of worker well being.
- Full Text:
- Date Issued: 2007
The reintroduction of large carnivores to the Eastern Cape, South Africa: an assessment
- Hayward, M W, Kerley, Graham I H, Adendorff, John, Moolman, Lucius C, O'Brien, John, Sholto-Douglas, Angus, Bissett, Charlene, Bean, Peter, Fogarty, Alan, Howarth, Dale, Slater, Richard
- Authors: Hayward, M W , Kerley, Graham I H , Adendorff, John , Moolman, Lucius C , O'Brien, John , Sholto-Douglas, Angus , Bissett, Charlene , Bean, Peter , Fogarty, Alan , Howarth, Dale , Slater, Richard
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6900 , http://hdl.handle.net/10962/d1011662 , http://dx.doi.org/10.1017/S0030605307001767
- Description: Recently, conservation estate in South Africa's Eastern Cape Province has increased 10-fold resulting in large predators being increasingly reintroduced to restore ecological integrity and maximize tourism. We describe the reintroductions of large carnivores (>10 kg) that have occurred in the Eastern Cape and use various criteria to assess their success. Lion Panthera leo reintroduction has been highly successful with a population of 56 currently extant in the region and problems of overpopulation arising. The African wild dog Lycaon pictus population has increased to 24 from a founder population of 11. Preliminary results for spotted hyaenas Crocuta crocuta also indicate success. Wild populations of leopards Panthera pardus exist on several reserves and have been supplemented by translocated individuals, although deaths of known individuals have occurred and no estimate of reproduction is available. Cheetah Acinonyx jubatus reintroduction has also been less successful with 36 individuals reintroduced and 23 cubs being born but only 41 individuals surviving in 2005. Criteria for assessing the success of reintroductions of species that naturally occur in low densities, such as top predators, generally have limited value. Carrying capacity for large predators is unknown and continued monitoring and intensive management will be necessary in enclosed, and possibly all, conservation areas in the Eastern Cape to ensure conservation success.
- Full Text:
- Date Issued: 2007
- Authors: Hayward, M W , Kerley, Graham I H , Adendorff, John , Moolman, Lucius C , O'Brien, John , Sholto-Douglas, Angus , Bissett, Charlene , Bean, Peter , Fogarty, Alan , Howarth, Dale , Slater, Richard
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6900 , http://hdl.handle.net/10962/d1011662 , http://dx.doi.org/10.1017/S0030605307001767
- Description: Recently, conservation estate in South Africa's Eastern Cape Province has increased 10-fold resulting in large predators being increasingly reintroduced to restore ecological integrity and maximize tourism. We describe the reintroductions of large carnivores (>10 kg) that have occurred in the Eastern Cape and use various criteria to assess their success. Lion Panthera leo reintroduction has been highly successful with a population of 56 currently extant in the region and problems of overpopulation arising. The African wild dog Lycaon pictus population has increased to 24 from a founder population of 11. Preliminary results for spotted hyaenas Crocuta crocuta also indicate success. Wild populations of leopards Panthera pardus exist on several reserves and have been supplemented by translocated individuals, although deaths of known individuals have occurred and no estimate of reproduction is available. Cheetah Acinonyx jubatus reintroduction has also been less successful with 36 individuals reintroduced and 23 cubs being born but only 41 individuals surviving in 2005. Criteria for assessing the success of reintroductions of species that naturally occur in low densities, such as top predators, generally have limited value. Carrying capacity for large predators is unknown and continued monitoring and intensive management will be necessary in enclosed, and possibly all, conservation areas in the Eastern Cape to ensure conservation success.
- Full Text:
- Date Issued: 2007
Comparison of satellite rainfall data with observations from gauging station networks
- Authors: Hughes, Denis A
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7079 , http://hdl.handle.net/10962/d1009748
- Description: Networks of ground-based hydro-meteorological observations are frequently sparse in developing countries and the situation is not improving. Part of the reason is the lack of resources available in countries which have more pressing economic and social issues. However, these are also the very countries where improved estimates of water resource availability are required. While hydrological models have the potential to provide the necessary information, without adequately accurate climate (rainfall, evaporation, etc.) input information, it is extremely difficult to establish models and generate representative water resource availability information. This paper reports on a preliminary analysis of the potential for using satellite derived rainfall data through a comparison with available gauge data for four basins in the southern Africa region. It is clear that the satellite data cannot be used directly in conjunction with historical gauge data. Specifically, the satellite data do not reflect the strong influences on precipitation of topography in some of the basins. However, the prospects of applying relatively straightforward adjustments are promising and further assessments appear to be justified.
- Full Text:
- Date Issued: 2006
- Authors: Hughes, Denis A
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7079 , http://hdl.handle.net/10962/d1009748
- Description: Networks of ground-based hydro-meteorological observations are frequently sparse in developing countries and the situation is not improving. Part of the reason is the lack of resources available in countries which have more pressing economic and social issues. However, these are also the very countries where improved estimates of water resource availability are required. While hydrological models have the potential to provide the necessary information, without adequately accurate climate (rainfall, evaporation, etc.) input information, it is extremely difficult to establish models and generate representative water resource availability information. This paper reports on a preliminary analysis of the potential for using satellite derived rainfall data through a comparison with available gauge data for four basins in the southern Africa region. It is clear that the satellite data cannot be used directly in conjunction with historical gauge data. Specifically, the satellite data do not reflect the strong influences on precipitation of topography in some of the basins. However, the prospects of applying relatively straightforward adjustments are promising and further assessments appear to be justified.
- Full Text:
- Date Issued: 2006
Temporal scales of variation in settlement and recruitment of the mussel Perna perna (Linnaeus, 1758)
- Porri, Francesca, McQuaid, Christopher D, Radloff, Sarah E
- Authors: Porri, Francesca , McQuaid, Christopher D , Radloff, Sarah E
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6963 , http://hdl.handle.net/10962/d1012026 , http://dx.doi.org/10.1016/j.jembe.2005.11.008
- Description: Population dynamics of many intertidal organisms are strongly affected by the abundance and distribution of larvae arriving on the shore. In particular, not only absolute numbers of settlers but also the degree of synchronisation of settlement can have a strong influence on whether density-dependent or density-independent processes shape adult shape populations. Temporal variation in rates of settlement and recruitment of the mussel Perna perna on the south coast of South Africa was investigated using a nested spatial design at different temporal scales. Variability in settlement at spring tides was examined at two temporal scales: lunar (to investigate the effect of state of the moon on settlement) and tidal (to investigate the influence of state of the tide on mussel settlement). Recruitment over neap tides was examined at one temporal scale, fortnight (to investigate the effect of date on mussel recruitment). Strong temporal variation was evident for both settlement and recruitment, but not at all time scales. Distinct peaks of settler/recruit abundance were observed during the lunar and neap tide studies. Recruitment intensity differed over the course of the year, and pulsing of recruitment was generally synchronised among locations. However, the strength of pulsing differed dramatically among locations, giving a significant interaction between fortnight and location. The finest temporal scale, investigated in the tidal study, did not reveal a significant effect of the state of the tide on settlement. The state of the moon (new or full) was not significant as a main factor (p = 0.052), although generally more settlers arrived on the shore during new moon. Phase of the moon appeared to have an effect on settler abundances, but only when and where densities were high.
- Full Text:
- Date Issued: 2006
- Authors: Porri, Francesca , McQuaid, Christopher D , Radloff, Sarah E
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6963 , http://hdl.handle.net/10962/d1012026 , http://dx.doi.org/10.1016/j.jembe.2005.11.008
- Description: Population dynamics of many intertidal organisms are strongly affected by the abundance and distribution of larvae arriving on the shore. In particular, not only absolute numbers of settlers but also the degree of synchronisation of settlement can have a strong influence on whether density-dependent or density-independent processes shape adult shape populations. Temporal variation in rates of settlement and recruitment of the mussel Perna perna on the south coast of South Africa was investigated using a nested spatial design at different temporal scales. Variability in settlement at spring tides was examined at two temporal scales: lunar (to investigate the effect of state of the moon on settlement) and tidal (to investigate the influence of state of the tide on mussel settlement). Recruitment over neap tides was examined at one temporal scale, fortnight (to investigate the effect of date on mussel recruitment). Strong temporal variation was evident for both settlement and recruitment, but not at all time scales. Distinct peaks of settler/recruit abundance were observed during the lunar and neap tide studies. Recruitment intensity differed over the course of the year, and pulsing of recruitment was generally synchronised among locations. However, the strength of pulsing differed dramatically among locations, giving a significant interaction between fortnight and location. The finest temporal scale, investigated in the tidal study, did not reveal a significant effect of the state of the tide on settlement. The state of the moon (new or full) was not significant as a main factor (p = 0.052), although generally more settlers arrived on the shore during new moon. Phase of the moon appeared to have an effect on settler abundances, but only when and where densities were high.
- Full Text:
- Date Issued: 2006
Valuation of communal area livestock benefits, rural livelihoods and related policy issues
- Dovie, Delali B K, Shackleton, Charlie M, Witkowski, Ed T F
- Authors: Dovie, Delali B K , Shackleton, Charlie M , Witkowski, Ed T F
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6627 , http://hdl.handle.net/10962/d1006819
- Description: The multiple benefits from livestock production to rural households are evaluated in Thorndale, a communal area of the Limpopo Province South Africa. Monetary values of livestock products are presented. Values from most previous studies are static (and thus outdated), as a result of conceptual and methodological shifts. The net monetary value of the direct benefits from livestock was estimated as $656 per household/annum, excluding the holding of cattle for savings. The net value is equivalent to 22.7% of the value of the other livelihood sources that were considered, and inclusive of cash income streams, crops, and secondary woodland resources. A net 168% herd increase in livestock was recorded between 1993 and 1999. More households owned goats compared to cattle, and cattle were important for use as draught power, and for milk. Households without livestock benefited through gifts and services, valued at $33 per household/annum. Policy concerns are the provision of adequate market and pricing mechanisms for communal area livestock, tailored savings, investment support, credit schemes, and infrastructure. An appropriate multipurpose benefit production model, other than a commercialised model is suggested for the sector.
- Full Text:
- Date Issued: 2006
- Authors: Dovie, Delali B K , Shackleton, Charlie M , Witkowski, Ed T F
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6627 , http://hdl.handle.net/10962/d1006819
- Description: The multiple benefits from livestock production to rural households are evaluated in Thorndale, a communal area of the Limpopo Province South Africa. Monetary values of livestock products are presented. Values from most previous studies are static (and thus outdated), as a result of conceptual and methodological shifts. The net monetary value of the direct benefits from livestock was estimated as $656 per household/annum, excluding the holding of cattle for savings. The net value is equivalent to 22.7% of the value of the other livelihood sources that were considered, and inclusive of cash income streams, crops, and secondary woodland resources. A net 168% herd increase in livestock was recorded between 1993 and 1999. More households owned goats compared to cattle, and cattle were important for use as draught power, and for milk. Households without livestock benefited through gifts and services, valued at $33 per household/annum. Policy concerns are the provision of adequate market and pricing mechanisms for communal area livestock, tailored savings, investment support, credit schemes, and infrastructure. An appropriate multipurpose benefit production model, other than a commercialised model is suggested for the sector.
- Full Text:
- Date Issued: 2006
Sperm morphology in four species of African platypleurine cicadas (Hemiptera: Cicadomorpha: Cicadidae)
- Chawanji, A S, Hodgson, Alan N, Villet, Martin H
- Authors: Chawanji, A S , Hodgson, Alan N , Villet, Martin H
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6917 , http://hdl.handle.net/10962/d1011880
- Description: Mature spermatozoa from four species of platypleurine cicadas (Albanycada albigera, Azanicada zuluensis, Platypleura capensis and P. hirtipennis) were examined by light and electron microscopy. The filiform sperm have a similar ultrastructure in all species but notable variations were found in sperm dimensions. All species produce more than one discrete length of nucleated, motile sperm, a form of polymorphism termed polymegaly. Polymegaly is expressed in two ways: sperm have bi- or trimodal head and tail lengths. The anterior parts of sperm heads are embedded in an elongate homogenous matrix forming a spermatodesm. The conical acrosome is deeply invaginated posteriorly, and sits on top of the nucleus. The acrosomal contents are differentiated internally with an electron-lucent central medulla and a denser cortex. The homogenously electron-dense nucleus is pointed anteriorly and is generally cylindrical, although posteriorly there is a lateral invagination that extends part-way along the nucleus. This invagination houses fine granular material of the centriolar adjunct. Vesicle-like elements that are associated with both the posterior nucleus and the centriolar adjunct are also found within the invagination. Immediately posterior of and adjoining the centriolar adjunct is a pair of mitochondrial derivatives that are elongated and extend for almost the entire length of the tail. The absence of accessory bodies in cicada sperm suggests that within the Cicadomorpha, the families Cicadidae and Cercopidae are closely affiliated.
- Full Text:
- Date Issued: 2005
- Authors: Chawanji, A S , Hodgson, Alan N , Villet, Martin H
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6917 , http://hdl.handle.net/10962/d1011880
- Description: Mature spermatozoa from four species of platypleurine cicadas (Albanycada albigera, Azanicada zuluensis, Platypleura capensis and P. hirtipennis) were examined by light and electron microscopy. The filiform sperm have a similar ultrastructure in all species but notable variations were found in sperm dimensions. All species produce more than one discrete length of nucleated, motile sperm, a form of polymorphism termed polymegaly. Polymegaly is expressed in two ways: sperm have bi- or trimodal head and tail lengths. The anterior parts of sperm heads are embedded in an elongate homogenous matrix forming a spermatodesm. The conical acrosome is deeply invaginated posteriorly, and sits on top of the nucleus. The acrosomal contents are differentiated internally with an electron-lucent central medulla and a denser cortex. The homogenously electron-dense nucleus is pointed anteriorly and is generally cylindrical, although posteriorly there is a lateral invagination that extends part-way along the nucleus. This invagination houses fine granular material of the centriolar adjunct. Vesicle-like elements that are associated with both the posterior nucleus and the centriolar adjunct are also found within the invagination. Immediately posterior of and adjoining the centriolar adjunct is a pair of mitochondrial derivatives that are elongated and extend for almost the entire length of the tail. The absence of accessory bodies in cicada sperm suggests that within the Cicadomorpha, the families Cicadidae and Cercopidae are closely affiliated.
- Full Text:
- Date Issued: 2005
Effects of substituents and solvents on the photochemical properties of zinc phthalocyanine complexes and their protonated derivatives
- Ogunsipe, Abimbola Olukayode, Nyokong, Tebello
- Authors: Ogunsipe, Abimbola Olukayode , Nyokong, Tebello
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6585 , http://hdl.handle.net/10962/d1004161
- Description: Zinc phthalocyanine derivatives containing various ring substituents and axial ligands were studied with respect to the effect of substituents on protonation. Aggregation resulted in failure of some of the ZnPc derivatives to protonate. In fact addition of protonating agents to aggregated ZnPc derivatives resulted in increase in aggregation followed by slow degradation. Axial ligands were lost on protonation. Photobleaching, fluorescence and singlet oxygen quantum yields of the protonated derivatives were compared with those of the unprotonated derivatives. In all cases protonation decreases the singlet oxygen and fluorescence quantum yields. However, photobleaching quantum yields decreased (i.e. stability increased) for the protonated derivatives except when axial ligands were present, where protonation resulted in decrease in stability.
- Full Text:
- Date Issued: 2004
- Authors: Ogunsipe, Abimbola Olukayode , Nyokong, Tebello
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6585 , http://hdl.handle.net/10962/d1004161
- Description: Zinc phthalocyanine derivatives containing various ring substituents and axial ligands were studied with respect to the effect of substituents on protonation. Aggregation resulted in failure of some of the ZnPc derivatives to protonate. In fact addition of protonating agents to aggregated ZnPc derivatives resulted in increase in aggregation followed by slow degradation. Axial ligands were lost on protonation. Photobleaching, fluorescence and singlet oxygen quantum yields of the protonated derivatives were compared with those of the unprotonated derivatives. In all cases protonation decreases the singlet oxygen and fluorescence quantum yields. However, photobleaching quantum yields decreased (i.e. stability increased) for the protonated derivatives except when axial ligands were present, where protonation resulted in decrease in stability.
- Full Text:
- Date Issued: 2004