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
The role of the privileged in responding to poverty: perspectives emerging from the post-development debate
- Authors: Matthews, Sally
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142476 , vital:38083 , DOI: 10.1080/01436590802201022
- Description: The debate between post-development theorists and their critics has raised several important questions, one of them being the question of how relatively privileged people may respond meaningfully to poverty while not perpetuating the flaws of past development practice. In this article I build upon the ideas of several contributors to the post-development debate in order to suggest three ways in which we who are relatively privileged may play a role in struggles against poverty. I argue that we can work to rethink the concepts informing development practice; that we may find ways to give our support to popular initiatives, and that there are aspects of our own societies which we may change in solidarity with the struggles of distant others.
- Full Text:
- Date Issued: 2008
- Authors: Matthews, Sally
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142476 , vital:38083 , DOI: 10.1080/01436590802201022
- Description: The debate between post-development theorists and their critics has raised several important questions, one of them being the question of how relatively privileged people may respond meaningfully to poverty while not perpetuating the flaws of past development practice. In this article I build upon the ideas of several contributors to the post-development debate in order to suggest three ways in which we who are relatively privileged may play a role in struggles against poverty. I argue that we can work to rethink the concepts informing development practice; that we may find ways to give our support to popular initiatives, and that there are aspects of our own societies which we may change in solidarity with the struggles of distant others.
- 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
Identity in the Siyagruva Series of novels: Toward an intercultural
- Authors: Kaschula, Russell H
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/175159 , vital:42548 , DOI: 10.4314/tvl.v44i2.29792
- Description: This article explores the notion of changing South African youth identity and how it is depicted in the Siyagruva [We are Grooving] Series of novels for young adults. The article highlights the need for a broadening of literary theory in order to include an appropriate theoretical approach for new South African youth literature. This theory explores intercultural literary discourse by making use of, for example, the work of intercultural theorists such as Ting-Toomey (1999), Gudykunst (2003) and others. It is argued that this form of literary discourse is now appropriate as a theoretical paradigm within multilingual South Africa where intercultural communication is becoming a reality. There is also reference to intracultural communication where differences are beginning to appear between young people who are perceived to come from the same cultural group, for example, the character Brunette in the Siyagruva Series who is perceived as a “coconut” by her friends, and thus finds herself having to justify her belonging within a particular in-group or culture. The article concentrates on selected novels, though reference is made to many of the twenty three published novels in the Siyagruva Series, twenty in English, and three translated into isiXhosa.
- Full Text:
- Date Issued: 2007
- Authors: Kaschula, Russell H
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/175159 , vital:42548 , DOI: 10.4314/tvl.v44i2.29792
- Description: This article explores the notion of changing South African youth identity and how it is depicted in the Siyagruva [We are Grooving] Series of novels for young adults. The article highlights the need for a broadening of literary theory in order to include an appropriate theoretical approach for new South African youth literature. This theory explores intercultural literary discourse by making use of, for example, the work of intercultural theorists such as Ting-Toomey (1999), Gudykunst (2003) and others. It is argued that this form of literary discourse is now appropriate as a theoretical paradigm within multilingual South Africa where intercultural communication is becoming a reality. There is also reference to intracultural communication where differences are beginning to appear between young people who are perceived to come from the same cultural group, for example, the character Brunette in the Siyagruva Series who is perceived as a “coconut” by her friends, and thus finds herself having to justify her belonging within a particular in-group or culture. The article concentrates on selected novels, though reference is made to many of the twenty three published novels in the Siyagruva Series, twenty in English, and three translated into isiXhosa.
- Full Text:
- Date Issued: 2007
Implementing innovative assessment methods in undergraduate Mathematics
- Authors: Matutu, Phethiwe P
- Date: 2007
- Language: English
- Type: Text
- Identifier: vital:6779 , http://hdl.handle.net/10962/d1006947
- Description: The following challenges associated with teaching undergraduate Mathematics will be discussed: Negative attitudes of students to Mathematics, Student’s reluctance to practise Mathematics, and surface learning. Some (or all) of the ways in which assessment can be used to address these challenges will be discussed. If used strategically assessment methods/tasks can enhance the teaching and learning of mathematics. Some of the unique challenges that we as lecturers face in teaching mathematics can be remedied by selecting appropriate assessment techniques/tasks. Using the tutorial time fruitfully is one of the challenging aspects in teaching mathematics. Not taking tutorials and other formative assessments seriously is not an uncommon student attitude in higher education contexts. Students who are pressured for time often do not see the immediate value of formative assessment or of discussion as a useful learning activity. A collection of case studies which clearly document what has been tried in different contexts is very useful in mathematics as this information is limited in the South African higher education sector. An innovative assessment method (peer-assessment) which was introduced for a Linear Algebra second year course at Rhodes University (South Africa) will be presented: The implementation method, purpose of introducing the assessment method, its advantages, and disadvantages will be examined. A reflection on the assessment method and concluding remarks will be provided.
- Full Text:
- Date Issued: 2007
- Authors: Matutu, Phethiwe P
- Date: 2007
- Language: English
- Type: Text
- Identifier: vital:6779 , http://hdl.handle.net/10962/d1006947
- Description: The following challenges associated with teaching undergraduate Mathematics will be discussed: Negative attitudes of students to Mathematics, Student’s reluctance to practise Mathematics, and surface learning. Some (or all) of the ways in which assessment can be used to address these challenges will be discussed. If used strategically assessment methods/tasks can enhance the teaching and learning of mathematics. Some of the unique challenges that we as lecturers face in teaching mathematics can be remedied by selecting appropriate assessment techniques/tasks. Using the tutorial time fruitfully is one of the challenging aspects in teaching mathematics. Not taking tutorials and other formative assessments seriously is not an uncommon student attitude in higher education contexts. Students who are pressured for time often do not see the immediate value of formative assessment or of discussion as a useful learning activity. A collection of case studies which clearly document what has been tried in different contexts is very useful in mathematics as this information is limited in the South African higher education sector. An innovative assessment method (peer-assessment) which was introduced for a Linear Algebra second year course at Rhodes University (South Africa) will be presented: The implementation method, purpose of introducing the assessment method, its advantages, and disadvantages will be examined. A reflection on the assessment method and concluding remarks will be provided.
- Full Text:
- Date Issued: 2007
Implications of life history for genetic structure and migration rates of southern African coastal invertebrates: planktonic, abbreviated and direct development
- Teske, Peter R, Papadopoulos, Isabelle, Zardi, Gerardo I, McQuaid, Christopher D, Edkins, M T, Griffiths, Charles L, Barker, Nigel P
- Authors: Teske, Peter R , Papadopoulos, Isabelle , Zardi, Gerardo I , McQuaid, Christopher D , Edkins, M T , Griffiths, Charles L , Barker, Nigel P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445447 , vital:74388 , https://doi.org/10.1007/s00227-007-0724-y
- Description: The amount of genetic structure in marine invertebrates is often thought to be negatively correlated with larval duration. However, larval retention may increase genetic structure in species with long-lived planktonic larvae, and rafting provides a means of dispersal for species that lack a larval dispersal phase. We compared genetic structure, demographic histories and levels of gene flow of regional lineages (in most cases defined by biogeographic region) of five southern African coastal invertebrates with three main types of larval development: (1) dispersal by long-lived planktonic larvae (mudprawn Upogebia africana and brown mussel Perna perna), (2) abbreviated larval development (crown crab Hymenosoma orbiculare) and (3) direct development (estuarine isopod Exosphaeroma hylecoetes and estuarine cumacean Iphinoe truncata). We hypothesized that H. orbiculare, having abbreviated larval development, would employ a strategy of larval retention, resulting in genetic structure comparable to that of the direct developers rather than the planktonic dispersers.
- Full Text:
- Date Issued: 2007
- Authors: Teske, Peter R , Papadopoulos, Isabelle , Zardi, Gerardo I , McQuaid, Christopher D , Edkins, M T , Griffiths, Charles L , Barker, Nigel P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445447 , vital:74388 , https://doi.org/10.1007/s00227-007-0724-y
- Description: The amount of genetic structure in marine invertebrates is often thought to be negatively correlated with larval duration. However, larval retention may increase genetic structure in species with long-lived planktonic larvae, and rafting provides a means of dispersal for species that lack a larval dispersal phase. We compared genetic structure, demographic histories and levels of gene flow of regional lineages (in most cases defined by biogeographic region) of five southern African coastal invertebrates with three main types of larval development: (1) dispersal by long-lived planktonic larvae (mudprawn Upogebia africana and brown mussel Perna perna), (2) abbreviated larval development (crown crab Hymenosoma orbiculare) and (3) direct development (estuarine isopod Exosphaeroma hylecoetes and estuarine cumacean Iphinoe truncata). We hypothesized that H. orbiculare, having abbreviated larval development, would employ a strategy of larval retention, resulting in genetic structure comparable to that of the direct developers rather than the planktonic dispersers.
- Full Text:
- Date Issued: 2007
Inflation targeting and the Fisher effect in South Africa: An empirical investigation
- Mitchell-Innes, Henry A, Aziakpono, Meshach J, Faure, Alexander P
- Authors: Mitchell-Innes, Henry A , Aziakpono, Meshach J , Faure, Alexander P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/469786 , vital:77294 , https://doi.org/10.1111/j.1813-6982.2007.00143.x
- Description: The paper analyses the relationship between expected inflation and nominal interest rates during a period of inflation targeting in South Africa, i.e. from 2000 to 2005. Specifically, it investigates the Fisher hypothesis that nominal interest rates move one‐to‐one with expected inflation, leaving the real interest rate unaffected. The analysis distinguishes between a short‐run Fisher effect and a long‐run Fisher effect. Using cointegration and error correction models (for monthly data for the period April 2000 to July 2005), it was found that the short‐run Fisher hypothesis did not hold during the relevant period under the inflation targeting monetary policy framework in South Africa. This is attributed to a combination of the South African Reserve Bank's (SARB) control over short‐term interest rates and the effects of the monetary transmission mechanism. The long‐run Fisher hypothesis could not be confirmed in its strictest form: while changes in inflation expectations move in the same direction as the nominal long‐term interest rate. This suggests that monetary policy has an influence on the real long-term interest rate, which has positive implications for general economic activity, thus confirming the credibility of the inflation targeting framework.
- Full Text:
- Date Issued: 2007
- Authors: Mitchell-Innes, Henry A , Aziakpono, Meshach J , Faure, Alexander P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/469786 , vital:77294 , https://doi.org/10.1111/j.1813-6982.2007.00143.x
- Description: The paper analyses the relationship between expected inflation and nominal interest rates during a period of inflation targeting in South Africa, i.e. from 2000 to 2005. Specifically, it investigates the Fisher hypothesis that nominal interest rates move one‐to‐one with expected inflation, leaving the real interest rate unaffected. The analysis distinguishes between a short‐run Fisher effect and a long‐run Fisher effect. Using cointegration and error correction models (for monthly data for the period April 2000 to July 2005), it was found that the short‐run Fisher hypothesis did not hold during the relevant period under the inflation targeting monetary policy framework in South Africa. This is attributed to a combination of the South African Reserve Bank's (SARB) control over short‐term interest rates and the effects of the monetary transmission mechanism. The long‐run Fisher hypothesis could not be confirmed in its strictest form: while changes in inflation expectations move in the same direction as the nominal long‐term interest rate. This suggests that monetary policy has an influence on the real long-term interest rate, which has positive implications for general economic activity, thus confirming the credibility of the inflation targeting framework.
- 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
Discourse domination?: the role of gender in seminar interaction
- De Klerk, Vivian A, Hunt, Sally
- Authors: De Klerk, Vivian A , Hunt, Sally
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/139160 , vital:37710 , https://www.ajol.info/index.php/salas/article/view/6501
- Description: This paper focuses on the effect of the gender of participants on the discourse patterns of university seminars, and compares the interaction patterns in two undergraduate seminars with those in two post-graduate seminars at Rhodes University. In the undergraduate seminars, two different groups of students at first year level in different disciplines were videotaped. The major difference was in terms of composition: in one seminar, there were equal numbers of male and female students, while in the other, female students dominated numerically (75%). In addition, five of the six formed a close-knit group of friends, which proved to be an important factor in the analysis. At the postgraduate level, the student participants were identical and met in the same venue and at the same time on two successive days to discuss the same topic (affirmative action in the workplace). The important difference between the two classes was the fact that the first seminar was led by a female tutor and the second seminar by a male tutor, both under 40 years of age and white, both members of staff in the department, and both known to the students. The discourse patterns in these two sets of seminars were analysed in order to investigate the ways in which the gender of tutors and students influenced the floor-winning and floor-holding conventions of participants.
- Full Text:
- Date Issued: 2004
- Authors: De Klerk, Vivian A , Hunt, Sally
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/139160 , vital:37710 , https://www.ajol.info/index.php/salas/article/view/6501
- Description: This paper focuses on the effect of the gender of participants on the discourse patterns of university seminars, and compares the interaction patterns in two undergraduate seminars with those in two post-graduate seminars at Rhodes University. In the undergraduate seminars, two different groups of students at first year level in different disciplines were videotaped. The major difference was in terms of composition: in one seminar, there were equal numbers of male and female students, while in the other, female students dominated numerically (75%). In addition, five of the six formed a close-knit group of friends, which proved to be an important factor in the analysis. At the postgraduate level, the student participants were identical and met in the same venue and at the same time on two successive days to discuss the same topic (affirmative action in the workplace). The important difference between the two classes was the fact that the first seminar was led by a female tutor and the second seminar by a male tutor, both under 40 years of age and white, both members of staff in the department, and both known to the students. The discourse patterns in these two sets of seminars were analysed in order to investigate the ways in which the gender of tutors and students influenced the floor-winning and floor-holding conventions of participants.
- Full Text:
- Date Issued: 2004
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
The early reception of Hill of Fools
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7040 , http://hdl.handle.net/10962/d1007379 , http://hdl.handle.net/10520/EJC47864
- Description: preprint , The early reception of Peteni’s novel is interesting because it illustrates the mind-sets and critical assumptions of those who first mediated the novel to different readerships. The book initially caused little stir either in South Africa or abroad, and it has made its way quietly in later years in no small part due to support from set-work prescription committees, and its translation into other media, radio and television. A one-off novel by an unknown writer is unlikely to gather critical momentum in international discussion, and the book has been more often noticed in academic studies focused on the Xhosa novel, some of which barely register that the work was first written in English. However, today it is certainly among the novels most widely-read by ordinary South Africans, not only those from the Eastern Cape, but for among many throughout the country who encountered it at school.
- Full Text:
- Date Issued: 2004
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7040 , http://hdl.handle.net/10962/d1007379 , http://hdl.handle.net/10520/EJC47864
- Description: preprint , The early reception of Peteni’s novel is interesting because it illustrates the mind-sets and critical assumptions of those who first mediated the novel to different readerships. The book initially caused little stir either in South Africa or abroad, and it has made its way quietly in later years in no small part due to support from set-work prescription committees, and its translation into other media, radio and television. A one-off novel by an unknown writer is unlikely to gather critical momentum in international discussion, and the book has been more often noticed in academic studies focused on the Xhosa novel, some of which barely register that the work was first written in English. However, today it is certainly among the novels most widely-read by ordinary South Africans, not only those from the Eastern Cape, but for among many throughout the country who encountered it at school.
- Full Text:
- Date Issued: 2004
Deepen the strategic relationship between the SACP and COSATU, with and for the workers and the poor
- Authors: Nzimande, Blade E
- Date: 2003-09-16
- Subjects: Cosatu -- Congresses , Labour unions -- South Africa -- Congresses , Industrial relations -- South Africa , South Africa -- Economic conditions -- 21st century , South Africa -- Politics and government -- 1994-
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/66245 , vital:28922
- Description: Cde President, Willie Madisha, Cde Zwelinzima Vavi, General Secretary and all COSATU national office-bearers, leadership of COSATU affiliates, leadership of the ANC present, Cde Jeremy Cronin and the SACP delegation, local and international guests, cde delegates. As the SACP we are deeply honoured by the invitation to come and address your congress. This occasion might go down in history as one of the most important congresses in the history of this Federation, this, the 8th Congress of the Congress of South African Trade Unions.
- Full Text:
- Date Issued: 2003-09-16
Deepen the strategic relationship between the SACP and COSATU, with and for the workers and the poor
- Authors: Nzimande, Blade E
- Date: 2003-09-16
- Subjects: Cosatu -- Congresses , Labour unions -- South Africa -- Congresses , Industrial relations -- South Africa , South Africa -- Economic conditions -- 21st century , South Africa -- Politics and government -- 1994-
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/66245 , vital:28922
- Description: Cde President, Willie Madisha, Cde Zwelinzima Vavi, General Secretary and all COSATU national office-bearers, leadership of COSATU affiliates, leadership of the ANC present, Cde Jeremy Cronin and the SACP delegation, local and international guests, cde delegates. As the SACP we are deeply honoured by the invitation to come and address your congress. This occasion might go down in history as one of the most important congresses in the history of this Federation, this, the 8th Congress of the Congress of South African Trade Unions.
- Full Text:
- Date Issued: 2003-09-16
Basalt geochemistry and tectonic discrimination within continental flood basalt provinces
- Authors: Marsh, Julian S
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140412 , vital:37886 , https://doi.org/10.1016/0377-0273(87)90035-7
- Description: Continental flood basalts are usually regarded as a single tectonomagmatic entity but frequently quoted examples exhibit a variety of tectonic settings. In one well-studied, classic, flood basalt province, the Mesozoic Karoo province of southern Africa, magmatism occurred in the following tectonic settings: (a) continental rifting leading to ocean-floor spreading in the South Atlantic Ocean (Etendeka suite of Namibia); (b) stretched continental lithosphere and rifting not leading directly to ocean-floor formation (Lebombo suite of southeastern Africa); and (c) an a-tectonic, within-plate, continental setting characterized by an absence of faulting or warping (Lesotho highlands and Karoo dolerites of South Africa).
- Full Text: false
- Date Issued: 2003
- Authors: Marsh, Julian S
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140412 , vital:37886 , https://doi.org/10.1016/0377-0273(87)90035-7
- Description: Continental flood basalts are usually regarded as a single tectonomagmatic entity but frequently quoted examples exhibit a variety of tectonic settings. In one well-studied, classic, flood basalt province, the Mesozoic Karoo province of southern Africa, magmatism occurred in the following tectonic settings: (a) continental rifting leading to ocean-floor spreading in the South Atlantic Ocean (Etendeka suite of Namibia); (b) stretched continental lithosphere and rifting not leading directly to ocean-floor formation (Lebombo suite of southeastern Africa); and (c) an a-tectonic, within-plate, continental setting characterized by an absence of faulting or warping (Lesotho highlands and Karoo dolerites of South Africa).
- Full Text: false
- Date Issued: 2003
Potter's fingerprints: some prehistoric southern African utilityware in an intimate light.
- Authors: Steele, John
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/945 , vital:30070
- Description: Extensive archaeological excavations in southern Africa during the past century have revealed a richly described heritage of widely distributed First-Millennium (C.E.) Agriculturist ceramics. In viewing both artefacts and assessments thereof it can be observed that ways of thinking shape ways of seeing, and explanations ofwhat is seen. Thus, because conceptual frameworks are inseparable from what is observed and explanations that result, consideration is given to some particular mindsets that have led to recent theories concenring local prehistoric material culture. In conclusion, a brief look at dialogues initiated by some contemporary potters who interrogate cherished lifeways and belief systems serve to elucidate current trends towards finding meaning in prehistoric southern African ceramics.
- Full Text:
- Date Issued: 2003
- Authors: Steele, John
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/945 , vital:30070
- Description: Extensive archaeological excavations in southern Africa during the past century have revealed a richly described heritage of widely distributed First-Millennium (C.E.) Agriculturist ceramics. In viewing both artefacts and assessments thereof it can be observed that ways of thinking shape ways of seeing, and explanations ofwhat is seen. Thus, because conceptual frameworks are inseparable from what is observed and explanations that result, consideration is given to some particular mindsets that have led to recent theories concenring local prehistoric material culture. In conclusion, a brief look at dialogues initiated by some contemporary potters who interrogate cherished lifeways and belief systems serve to elucidate current trends towards finding meaning in prehistoric southern African ceramics.
- Full Text:
- Date Issued: 2003