Phylogenetic congruence of mealybugs and their primary endosymbionts
- Authors: Downie, D A , Gullan, P J
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6905 , http://hdl.handle.net/10962/d1011858 , http://dx.doi.org/10.1111/j.1420-9101.2004.00834.x
- Description: Tight interactions between unrelated organisms such as is seen in plant–insect, host–parasite, or host–symbiont associations may lead to speciation of the smaller partners when their hosts speciate. Totally congruent phylogenies of interacting taxa have not been observed often but a number of studies have provided evidence that various hemipteran insect taxa and their primary bacterial endosymbionts share phylogenetic histories. Like other hemipterans, mealybugs (Pseudococcidae) harbour multiple intracellular bacterial symbionts, which are thought to be strictly vertically inherited, implying codivergence of hosts and symbionts. Here, robust estimates of phylogeny were generated from four fragments of three nuclear genes for mealybugs of the subfamily Pseudococcinae, and a substantial fragment of the 16S–23S rDNA of their P-endosymbionts. Phylogenetic congruence was highly significant, with 75% of nodes on the two trees identical, and significant correlation of branch lengths indicated coincident timing of cladogenesis. It is suggested that the low level of observed incongruence was influenced by uncertainty in phylogenetic estimation, but evolutionary outcomes other than congruence, including host shifts, could not be rejected.
- Full Text:
- Date Issued: 2005
- Authors: Downie, D A , Gullan, P J
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6905 , http://hdl.handle.net/10962/d1011858 , http://dx.doi.org/10.1111/j.1420-9101.2004.00834.x
- Description: Tight interactions between unrelated organisms such as is seen in plant–insect, host–parasite, or host–symbiont associations may lead to speciation of the smaller partners when their hosts speciate. Totally congruent phylogenies of interacting taxa have not been observed often but a number of studies have provided evidence that various hemipteran insect taxa and their primary bacterial endosymbionts share phylogenetic histories. Like other hemipterans, mealybugs (Pseudococcidae) harbour multiple intracellular bacterial symbionts, which are thought to be strictly vertically inherited, implying codivergence of hosts and symbionts. Here, robust estimates of phylogeny were generated from four fragments of three nuclear genes for mealybugs of the subfamily Pseudococcinae, and a substantial fragment of the 16S–23S rDNA of their P-endosymbionts. Phylogenetic congruence was highly significant, with 75% of nodes on the two trees identical, and significant correlation of branch lengths indicated coincident timing of cladogenesis. It is suggested that the low level of observed incongruence was influenced by uncertainty in phylogenetic estimation, but evolutionary outcomes other than congruence, including host shifts, could not be rejected.
- Full Text:
- Date Issued: 2005
Pictograms in pharmacy:
- Dowse, Roslind, Ehlers, Martina S
- Authors: Dowse, Roslind , Ehlers, Martina S
- Date: 1998
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157048 , vital:40082 , https://0-doi.org.wam.seals.ac.za/10.1111/j.2042-7174.1998.tb00924.x
- Description: This review examines the use of pictograms in health care. Well designed pictograms are simple, clear, graphic symbols able to convey their intended meaning to all patients, including those who are illiterate, elderly or visually impaired. Although some research on the effectiveness of pictograms has not supported the hypothesis that pictograms are beneficial for the acquisition and comprehension of information, most studies investigating health‐related applications of pictograms have shown them to be of benefit in the comprehension and recall of instructions on prescription and over‐the‐counter medicines. However, the success of pictograms as a communication aid in pharmacy depends first on a rigorous design process, followed by well‐designed, randomised, controlled trials using an appropriate method of evaluation. The final stage is to investigate the optimal way of using pictograms in practice and to assess their effect on behavioural outcomes, such as compliance.
- Full Text:
- Date Issued: 1998
- Authors: Dowse, Roslind , Ehlers, Martina S
- Date: 1998
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157048 , vital:40082 , https://0-doi.org.wam.seals.ac.za/10.1111/j.2042-7174.1998.tb00924.x
- Description: This review examines the use of pictograms in health care. Well designed pictograms are simple, clear, graphic symbols able to convey their intended meaning to all patients, including those who are illiterate, elderly or visually impaired. Although some research on the effectiveness of pictograms has not supported the hypothesis that pictograms are beneficial for the acquisition and comprehension of information, most studies investigating health‐related applications of pictograms have shown them to be of benefit in the comprehension and recall of instructions on prescription and over‐the‐counter medicines. However, the success of pictograms as a communication aid in pharmacy depends first on a rigorous design process, followed by well‐designed, randomised, controlled trials using an appropriate method of evaluation. The final stage is to investigate the optimal way of using pictograms in practice and to assess their effect on behavioural outcomes, such as compliance.
- Full Text:
- Date Issued: 1998
Policies to reduce single-use plastic marine pollution in West Africa:
- Adam, Issahaku, Walker, Tony R, Bezerra, Joana Carlos, Clayton, Andrea
- Authors: Adam, Issahaku , Walker, Tony R , Bezerra, Joana Carlos , Clayton, Andrea
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150196 , vital:38948 , https://doi.org/10.1016/j.marpol.2020.103928
- Description: Countries in Africa are increasingly adopting policies to reduce single-use plastic (SUP) pollution, yet there has been limited analysis of policies adopted by African countries. This paper reviews SUP reduction policies, specifically in West Africa.
- Full Text:
- Date Issued: 2020
- Authors: Adam, Issahaku , Walker, Tony R , Bezerra, Joana Carlos , Clayton, Andrea
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150196 , vital:38948 , https://doi.org/10.1016/j.marpol.2020.103928
- Description: Countries in Africa are increasingly adopting policies to reduce single-use plastic (SUP) pollution, yet there has been limited analysis of policies adopted by African countries. This paper reviews SUP reduction policies, specifically in West Africa.
- Full Text:
- Date Issued: 2020
Post-traumatic stress disorder as a public health concern in South Africa
- Authors: Edwards, D J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6229 , http://hdl.handle.net/10962/d1007779
- Description: This article briefly surveys the extent to which traumatic events are a feature of life all over Africa and provides a comprehensive review of research that documents the pervasiveness of traumatic events in South Africa and the prevalence of PTSD symptoms. The material reviewed includes statistics on crime, violence and accidents, research from clinical settings, and surveys. Several provide evidence for the causal link between traumatic events and the development of PTSD. These studies show that PTSD has been and continues to be a significant problem for public health in South Africa, affecting individuals in all sectors of society and as much a concern with respect to children as to adults.
- Full Text:
- Date Issued: 2005
- Authors: Edwards, D J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6229 , http://hdl.handle.net/10962/d1007779
- Description: This article briefly surveys the extent to which traumatic events are a feature of life all over Africa and provides a comprehensive review of research that documents the pervasiveness of traumatic events in South Africa and the prevalence of PTSD symptoms. The material reviewed includes statistics on crime, violence and accidents, research from clinical settings, and surveys. Several provide evidence for the causal link between traumatic events and the development of PTSD. These studies show that PTSD has been and continues to be a significant problem for public health in South Africa, affecting individuals in all sectors of society and as much a concern with respect to children as to adults.
- Full Text:
- Date Issued: 2005
Prediction of water temperature metrics using spatial modelling in the Eastern and Western Cape, South Africa
- Rivers-Moore, N A, Mantel, S, Dallas, H F
- Authors: Rivers-Moore, N A , Mantel, S , Dallas, H F
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:7071 , http://hdl.handle.net/10962/d1003947 , http://www.scielo.org.za/scielo.php?pid=S1816-79502012000200002&script=sci_arttext
- Description: Key aspects of a river's temperature regime are described by magnitudes, timing and durations of thermal events, and frequencies of extreme exceedance events. To understand alterations to thermal regimes, it is necessary to describe thermal time series based on these statistics. Classification of sites based on their thermal metrics, and understanding of spatial patterns of these thermal statistics, provides a powerful approach for comparing study sites against reference sites. Water temperature regime dynamics should be viewed regionally, where regional divisions have an inherent underpinning by an understanding of natural thermal variability. The aim of this research was to link key water temperature metrics to readily-mapped environmental surrogates, and to produce spatial images of temperature metrics: 37 temperature metrics were derived for 12 months of sub-daily water temperatures at 90 sites in the Eastern Cape and Western Cape provinces, South Africa. These metrics were correlated with 16 environmental variables. Correlations enabled development of multiple regression models which facilitated mapping of temperature metrics over the study area. This approach has the potential to be applied at a national scale as more thermal time series are collected nationally. It is argued that the appropriateness of management decisions in rivers can be improved by including guidelines for thermal metrics at a regional scale. Such maps could facilitate incorporation of a temperature component into management guidelines for water resources.
- Full Text:
- Date Issued: 2012
- Authors: Rivers-Moore, N A , Mantel, S , Dallas, H F
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:7071 , http://hdl.handle.net/10962/d1003947 , http://www.scielo.org.za/scielo.php?pid=S1816-79502012000200002&script=sci_arttext
- Description: Key aspects of a river's temperature regime are described by magnitudes, timing and durations of thermal events, and frequencies of extreme exceedance events. To understand alterations to thermal regimes, it is necessary to describe thermal time series based on these statistics. Classification of sites based on their thermal metrics, and understanding of spatial patterns of these thermal statistics, provides a powerful approach for comparing study sites against reference sites. Water temperature regime dynamics should be viewed regionally, where regional divisions have an inherent underpinning by an understanding of natural thermal variability. The aim of this research was to link key water temperature metrics to readily-mapped environmental surrogates, and to produce spatial images of temperature metrics: 37 temperature metrics were derived for 12 months of sub-daily water temperatures at 90 sites in the Eastern Cape and Western Cape provinces, South Africa. These metrics were correlated with 16 environmental variables. Correlations enabled development of multiple regression models which facilitated mapping of temperature metrics over the study area. This approach has the potential to be applied at a national scale as more thermal time series are collected nationally. It is argued that the appropriateness of management decisions in rivers can be improved by including guidelines for thermal metrics at a regional scale. Such maps could facilitate incorporation of a temperature component into management guidelines for water resources.
- Full Text:
- Date Issued: 2012
Preference for C4 shade grasses increases hatchling performance in the butterfly, Bicyclus safitza
- Nokelainen, Ossi, Ripley, Bradford Sherman, Van Bergen, Erik, Osborne, Colin P, Brakefield, Paul M
- Authors: Nokelainen, Ossi , Ripley, Bradford Sherman , Van Bergen, Erik , Osborne, Colin P , Brakefield, Paul M
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61424 , vital:28025 , http://onlinelibrary.wiley.com/doi/10.1002/ece3.2235/full
- Description: The Miocene radiation of C4 grasses under high-temperature and low ambient CO2 levels occurred alongside the transformation of a largely forested landscape into savanna. This inevitably changed the host plant regime of herbivores, and the simultaneous diversification of many consumer lineages, including Bicyclus butterflies in Africa, suggests that the radiations of grasses and grazers may be evolutionary linked. We examined mechanisms for this plant–herbivore interaction with the grass-feeding Bicyclus safitza in South Africa. In a controlled environment, we tested oviposition preference and hatchling performance on local grasses with C3 or C4 photosynthetic pathways that grow either in open or shaded habitats. We predicted preference for C3 plants due to a hypothesized lower processing cost and higher palatability to herbivores. In contrast, we found that females preferred C4 shade grasses rather than either C4 grasses from open habitats or C3 grasses. The oviposition preference broadly followed hatchling performance, although hatchling survival was equally good on C4 or C3 shade grasses. This finding was explained by leaf toughness; shade grasses were softer than grasses from open habitats. Field monitoring revealed a preference of adults for shaded habitats, and stable isotope analysis of field-sampled individuals confirmed their preference for C4 grasses as host plants. Our findings suggest that plant–herbivore interactions can influence the direction of selection in a grass-feeding butterfly. Based on this work, we postulate future research to test whether these interactions more generally contribute to radiations in herbivorous insects via expansions into new, unexploited ecological niches.
- Full Text:
- Date Issued: 2016
- Authors: Nokelainen, Ossi , Ripley, Bradford Sherman , Van Bergen, Erik , Osborne, Colin P , Brakefield, Paul M
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61424 , vital:28025 , http://onlinelibrary.wiley.com/doi/10.1002/ece3.2235/full
- Description: The Miocene radiation of C4 grasses under high-temperature and low ambient CO2 levels occurred alongside the transformation of a largely forested landscape into savanna. This inevitably changed the host plant regime of herbivores, and the simultaneous diversification of many consumer lineages, including Bicyclus butterflies in Africa, suggests that the radiations of grasses and grazers may be evolutionary linked. We examined mechanisms for this plant–herbivore interaction with the grass-feeding Bicyclus safitza in South Africa. In a controlled environment, we tested oviposition preference and hatchling performance on local grasses with C3 or C4 photosynthetic pathways that grow either in open or shaded habitats. We predicted preference for C3 plants due to a hypothesized lower processing cost and higher palatability to herbivores. In contrast, we found that females preferred C4 shade grasses rather than either C4 grasses from open habitats or C3 grasses. The oviposition preference broadly followed hatchling performance, although hatchling survival was equally good on C4 or C3 shade grasses. This finding was explained by leaf toughness; shade grasses were softer than grasses from open habitats. Field monitoring revealed a preference of adults for shaded habitats, and stable isotope analysis of field-sampled individuals confirmed their preference for C4 grasses as host plants. Our findings suggest that plant–herbivore interactions can influence the direction of selection in a grass-feeding butterfly. Based on this work, we postulate future research to test whether these interactions more generally contribute to radiations in herbivorous insects via expansions into new, unexploited ecological niches.
- Full Text:
- Date Issued: 2016
Public green space inequality in small towns in South Africa
- McConnachie, Matthew M, Shackleton, Charlie M
- Authors: McConnachie, Matthew M , Shackleton, Charlie M
- Date: 2010
- Language: English
- Type: Article
- Identifier: vital:6644 , http://hdl.handle.net/10962/d1006874
- Description: The distribution of public green space within towns is frequently uneven, and influenced by attributes such as its location relative to the commercial core, as well as the ethnicity and relative wealth and education of the residents. Yet most studies are from large cities in developed countries. In contrast, this study reports on the distribution of public green space across 9 small towns in a developing country, namely South Africa, which offers a unique case study because of its former racially defined settlement patterns. We do so using GIS analysis of aerial photographs focusing on 3 types of suburbs in each town, defined on the basis of wealth as well as race-based history under the previous apartheid regime. The more affluent suburbs, inhabited mainly by whites, have the lowest density of housing and the highest area of green space per capita. Proportionally, they have a similar area under public green space as to the previously racially defined townships, but because of the lower housing density, they have a greater area per person. The newly built low-cost housing areas (termed RDP suburbs), occupied largely by poor black South Africans, are poorly endowed with public green space, and fare worse than the other 2 suburb types on all attributes measured. This needs to be addressed in further low-cost housing developments.
- Full Text:
- Date Issued: 2010
- Authors: McConnachie, Matthew M , Shackleton, Charlie M
- Date: 2010
- Language: English
- Type: Article
- Identifier: vital:6644 , http://hdl.handle.net/10962/d1006874
- Description: The distribution of public green space within towns is frequently uneven, and influenced by attributes such as its location relative to the commercial core, as well as the ethnicity and relative wealth and education of the residents. Yet most studies are from large cities in developed countries. In contrast, this study reports on the distribution of public green space across 9 small towns in a developing country, namely South Africa, which offers a unique case study because of its former racially defined settlement patterns. We do so using GIS analysis of aerial photographs focusing on 3 types of suburbs in each town, defined on the basis of wealth as well as race-based history under the previous apartheid regime. The more affluent suburbs, inhabited mainly by whites, have the lowest density of housing and the highest area of green space per capita. Proportionally, they have a similar area under public green space as to the previously racially defined townships, but because of the lower housing density, they have a greater area per person. The newly built low-cost housing areas (termed RDP suburbs), occupied largely by poor black South Africans, are poorly endowed with public green space, and fare worse than the other 2 suburb types on all attributes measured. This needs to be addressed in further low-cost housing developments.
- Full Text:
- Date Issued: 2010
Recommendations for the future of recreational fisheries to prepare the social‐ecological system to cope with change
- Arlinghaus, Robert, Cooke, Steven J, Sutton, S G, Danylchuk, A J, Potts, Warren M, Freire, K D M, Alós, J, Da Silva, E T, Cowx, Ian G, Van Anrooy, R
- Authors: Arlinghaus, Robert , Cooke, Steven J , Sutton, S G , Danylchuk, A J , Potts, Warren M , Freire, K D M , Alós, J , Da Silva, E T , Cowx, Ian G , Van Anrooy, R
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125810 , vital:35819 , https://doi.10.1111/fme.12191
- Description: This paper presents conclusions and recommendations that emerged from the 7th World Recreational Fishing Conference (WRFC) held in Campinas, Brazil in September 2014. Based on the recognition of the immense social and economic importance of recreational fisheries coupled with weaknesses in robust information about these fisheries in many areas of the world, particularly in many economies in transition, it is recommended to increase effort to build effective governance arrangements and improve monitoring and assessment frameworks in data-poor situations. Moreover, there is a need to increase interdisciplinary studies that will foster a systematic understanding of recreational fisheries as complex adaptive social-ecological systems. To promote sustainable recreational fisheries on a global scale, it is recommended the detailed suggestions for governance and management outlined in the United Nations Food and Agricultural Organization Technical Guidelines for Responsible Fisheries: Recreational Fisheries are followed.
- Full Text:
- Date Issued: 2016
- Authors: Arlinghaus, Robert , Cooke, Steven J , Sutton, S G , Danylchuk, A J , Potts, Warren M , Freire, K D M , Alós, J , Da Silva, E T , Cowx, Ian G , Van Anrooy, R
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125810 , vital:35819 , https://doi.10.1111/fme.12191
- Description: This paper presents conclusions and recommendations that emerged from the 7th World Recreational Fishing Conference (WRFC) held in Campinas, Brazil in September 2014. Based on the recognition of the immense social and economic importance of recreational fisheries coupled with weaknesses in robust information about these fisheries in many areas of the world, particularly in many economies in transition, it is recommended to increase effort to build effective governance arrangements and improve monitoring and assessment frameworks in data-poor situations. Moreover, there is a need to increase interdisciplinary studies that will foster a systematic understanding of recreational fisheries as complex adaptive social-ecological systems. To promote sustainable recreational fisheries on a global scale, it is recommended the detailed suggestions for governance and management outlined in the United Nations Food and Agricultural Organization Technical Guidelines for Responsible Fisheries: Recreational Fisheries are followed.
- Full Text:
- Date Issued: 2016
Rehearsing or reversing harmful masculine scripts?: South African men's romance narratives
- Vincent, Louise, Chiwandire, Desire
- Authors: Vincent, Louise , Chiwandire, Desire
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141844 , vital:38009 , DOI: 10.1080/10130950.2013.807081
- Description: In this Article we discuss the results of 42 in-depth qualitative interviews with young black South African men who self-identified as heterosexual and who reported that they were at the time of the interview or had at some time in their lives, experienced being ‘in love’ with a woman. South Africa, as is commonly pointed out, is in the throes of an epidemic of gender based violence. To declare oneself ‘in love’ potentially contradicts some of the core features of what Mogomotsi Mfalapitsa (IRIN, 2009) has referred to as ‘harmful masculinity’ and which he has argued is causally related to male violence against women. These features include emotional detachment, promiscuity, interest in casual sex rather than long-term engagement with a single partner, unwillingness to be ‘tied down’, the hierarchical ordering of gendered relations constructed as men's entitlement to women's ‘respect’ and the need to publically enact masculine heterosexuality. We are interested in whether, in these narratives, the research participants position themselves in opposition to these harmful precepts or, whether they confirm and reiteratively perform assumptions that can be construed as damaging to the prospects of generating more equitable, fair and loving relations between men and women.
- Full Text:
- Date Issued: 2013
- Authors: Vincent, Louise , Chiwandire, Desire
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141844 , vital:38009 , DOI: 10.1080/10130950.2013.807081
- Description: In this Article we discuss the results of 42 in-depth qualitative interviews with young black South African men who self-identified as heterosexual and who reported that they were at the time of the interview or had at some time in their lives, experienced being ‘in love’ with a woman. South Africa, as is commonly pointed out, is in the throes of an epidemic of gender based violence. To declare oneself ‘in love’ potentially contradicts some of the core features of what Mogomotsi Mfalapitsa (IRIN, 2009) has referred to as ‘harmful masculinity’ and which he has argued is causally related to male violence against women. These features include emotional detachment, promiscuity, interest in casual sex rather than long-term engagement with a single partner, unwillingness to be ‘tied down’, the hierarchical ordering of gendered relations constructed as men's entitlement to women's ‘respect’ and the need to publically enact masculine heterosexuality. We are interested in whether, in these narratives, the research participants position themselves in opposition to these harmful precepts or, whether they confirm and reiteratively perform assumptions that can be construed as damaging to the prospects of generating more equitable, fair and loving relations between men and women.
- Full Text:
- Date Issued: 2013
Reproductive and feeding biology of the Natal mountain catfish, Amphilius natalensis (Siluriformes: Amphiliidae)
- Marriott, Michael S, Booth, Anthony J, Skelton, Paul H (Paul Harvey)
- Authors: Marriott, Michael S , Booth, Anthony J , Skelton, Paul H (Paul Harvey)
- Date: 1997
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125837 , vital:35823 , https://doi.10.1023/A:1007361511052
- Description: The family Amphiliidae comprises nine genera and about 60 species. Only five species are found in southern Africa, three of which belong to the genus Amphilius (Skelton 1993). These soft-bodied catlets inhabit clear, fast flowing mountain streams where they live amongst cobbles, feeding predominantly on benthic invertebrates (Crass 1964, Skelton 1993). The Natal mountain catfish, A. natalensis Boulenger, 1917, is a small, nocturnal species with a restricted distribution along the eastern seaboard of southern Africa. It occurs in mountain streams from the Umkomaas River north to the Limpopo system in South Africa. It is also present in the Marozi River, a tributary of the Zambezi River in Zimbabwe and in the Ruo River, Malawi (Skelton 1984, 1993). Skelton (1993) suggested that predation by introduced trout species has led to scarcity of A. natalensis in many streams. In spite of this, no studies on the biology of this catfish species have been published. This study presents the first quantitative information on the biology of an amphiliid catfish, A. natalensis including gametogenesis, spawning seasonality, size-at-maturity, adult sex ratio and diet.
- Full Text:
- Date Issued: 1997
- Authors: Marriott, Michael S , Booth, Anthony J , Skelton, Paul H (Paul Harvey)
- Date: 1997
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125837 , vital:35823 , https://doi.10.1023/A:1007361511052
- Description: The family Amphiliidae comprises nine genera and about 60 species. Only five species are found in southern Africa, three of which belong to the genus Amphilius (Skelton 1993). These soft-bodied catlets inhabit clear, fast flowing mountain streams where they live amongst cobbles, feeding predominantly on benthic invertebrates (Crass 1964, Skelton 1993). The Natal mountain catfish, A. natalensis Boulenger, 1917, is a small, nocturnal species with a restricted distribution along the eastern seaboard of southern Africa. It occurs in mountain streams from the Umkomaas River north to the Limpopo system in South Africa. It is also present in the Marozi River, a tributary of the Zambezi River in Zimbabwe and in the Ruo River, Malawi (Skelton 1984, 1993). Skelton (1993) suggested that predation by introduced trout species has led to scarcity of A. natalensis in many streams. In spite of this, no studies on the biology of this catfish species have been published. This study presents the first quantitative information on the biology of an amphiliid catfish, A. natalensis including gametogenesis, spawning seasonality, size-at-maturity, adult sex ratio and diet.
- Full Text:
- Date Issued: 1997
Reproductive biology of a riverine cyprinid, Labeo umbratus (Teleostei: Cyprinidae), in small South African reservoirs
- Potts, Warren M, Booth, Anthony J, Hecht, Thomas, Andrew, Timothy G
- Authors: Potts, Warren M , Booth, Anthony J , Hecht, Thomas , Andrew, Timothy G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125854 , vital:35826 , https://doi.10.2989/16085910509503849
- Description: The reproductive and recruitment characteristics of moggel, Labeo umbratus, populations were examined in four small South African reservoirs. Reproduction, characterised by an extended spawning season, high fecundity, short incubation time and rapid larval development, appears to be ideally suited to the highly variable environment of small reservoirs. Evidence suggested that L. umbratus spawns in the reservoirs. In two reservoirs where samples were conducted monthly, GSI (gonado-somatic index) was positively correlated with both water temperature and day length, whilst the CPUE (catch per unit effort) of juveniles was not related to any environmental variable. The success of moggel spawning appeared to increase when there was early spring and consistent summer rainfall.
- Full Text:
- Date Issued: 2010
- Authors: Potts, Warren M , Booth, Anthony J , Hecht, Thomas , Andrew, Timothy G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125854 , vital:35826 , https://doi.10.2989/16085910509503849
- Description: The reproductive and recruitment characteristics of moggel, Labeo umbratus, populations were examined in four small South African reservoirs. Reproduction, characterised by an extended spawning season, high fecundity, short incubation time and rapid larval development, appears to be ideally suited to the highly variable environment of small reservoirs. Evidence suggested that L. umbratus spawns in the reservoirs. In two reservoirs where samples were conducted monthly, GSI (gonado-somatic index) was positively correlated with both water temperature and day length, whilst the CPUE (catch per unit effort) of juveniles was not related to any environmental variable. The success of moggel spawning appeared to increase when there was early spring and consistent summer rainfall.
- Full Text:
- Date Issued: 2010
Reproductive biology of ningu, Labeo victorianus (pisces: cyprinidae), in the kagera and Sio rivers, Uganda
- Rutaisire, Justus, Booth, Anthony J
- Authors: Rutaisire, Justus , Booth, Anthony J
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125864 , vital:35827 , https://doi.10.1007/s10641-004-5564-8
- Description: We investigated aspects of the reproductive biology of the cyprinid fish, Labeo victorianus, locally known as ningu, in the Kagera and Sio Rivers, Uganda. These rivers represent the last remaining refuges for this species within Uganda. L. victorianus is a highly fecund, potamodrometic fish that migrates upstream to spawn. Spawning is generally synchronised with the bimodal water level maxima observed within the rivers. There were, however, some deviations from this pattern. We caught sexually mature fish throughout the year in the Sio River, and noticed that spawing started before the second rainfall peak. Fish from the Kagera matured at significantly larger sizes than fish from the Sio River. Male and female fish, from both rivers, fed intensively during the non-breeding months accumulating significant fat reserves; a probable energy storage mechanism prior to their spawning migrations. The differences between the populations is probably a phenotypic response to differing abiotic factors such as river size, flow velocity and food availability.
- Full Text:
- Date Issued: 2005
- Authors: Rutaisire, Justus , Booth, Anthony J
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125864 , vital:35827 , https://doi.10.1007/s10641-004-5564-8
- Description: We investigated aspects of the reproductive biology of the cyprinid fish, Labeo victorianus, locally known as ningu, in the Kagera and Sio Rivers, Uganda. These rivers represent the last remaining refuges for this species within Uganda. L. victorianus is a highly fecund, potamodrometic fish that migrates upstream to spawn. Spawning is generally synchronised with the bimodal water level maxima observed within the rivers. There were, however, some deviations from this pattern. We caught sexually mature fish throughout the year in the Sio River, and noticed that spawing started before the second rainfall peak. Fish from the Kagera matured at significantly larger sizes than fish from the Sio River. Male and female fish, from both rivers, fed intensively during the non-breeding months accumulating significant fat reserves; a probable energy storage mechanism prior to their spawning migrations. The differences between the populations is probably a phenotypic response to differing abiotic factors such as river size, flow velocity and food availability.
- Full Text:
- Date Issued: 2005
Restructuring manufacturing in South Africa's lagging regions : the case of the Free State
- Nel, Etienne L, Rogerson, C M, Marais, L
- Authors: Nel, Etienne L , Rogerson, C M , Marais, L
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6714 , http://hdl.handle.net/10962/d1006786
- Description: The manufacturing economy of the Free State reflects both historical dependence on locally available raw materials and high-levels of state intervention, in terms of support for import substitution and Homeland development. In the contemporary era, deindustrialization, the uncertain future of the clothing / textile industries and limited growth over the last ten years, suggests that, in terms of manufacturing, the Free State is a 'lagging' region. While there has been significant expansion in the number of small firms, this is not matched by employment growth and does not compensate for the loss of many large firms and economic downscaling in the Goldfields. Key sectors such as petro-chemicals and gold jewellery present certain opportunities for future growth.
- Full Text:
- Date Issued: 2006
- Authors: Nel, Etienne L , Rogerson, C M , Marais, L
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6714 , http://hdl.handle.net/10962/d1006786
- Description: The manufacturing economy of the Free State reflects both historical dependence on locally available raw materials and high-levels of state intervention, in terms of support for import substitution and Homeland development. In the contemporary era, deindustrialization, the uncertain future of the clothing / textile industries and limited growth over the last ten years, suggests that, in terms of manufacturing, the Free State is a 'lagging' region. While there has been significant expansion in the number of small firms, this is not matched by employment growth and does not compensate for the loss of many large firms and economic downscaling in the Goldfields. Key sectors such as petro-chemicals and gold jewellery present certain opportunities for future growth.
- Full Text:
- Date Issued: 2006
Rethinking the dialectics of rural and urban in African art and scholarship:
- Siegenthaler, Fiona, Nzewi, Ugochukwu-Smooth C, Siegert, Nadine
- Authors: Siegenthaler, Fiona , Nzewi, Ugochukwu-Smooth C , Siegert, Nadine
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146022 , vital:38488 , DOI: 10.1080/19301944.2018.1538856
- Description: This issue of Critical Interventions is dedicated to rethinking the dialectics of the rural and the urban in African art and scholarship. Inspired by the general theme of the European Conference of African Studies (ECAS/AEGIS) in Basel (June 28 to July 1, 2017), Urban Africa – Urban Africans: New Encounters of the Rural and the Urban, the guest editors of this issue hosted two panels on the relationship of urban-based artists and their interest in rural topographies, aesthetics, and cultural practices.
- Full Text:
- Date Issued: 2019
- Authors: Siegenthaler, Fiona , Nzewi, Ugochukwu-Smooth C , Siegert, Nadine
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146022 , vital:38488 , DOI: 10.1080/19301944.2018.1538856
- Description: This issue of Critical Interventions is dedicated to rethinking the dialectics of the rural and the urban in African art and scholarship. Inspired by the general theme of the European Conference of African Studies (ECAS/AEGIS) in Basel (June 28 to July 1, 2017), Urban Africa – Urban Africans: New Encounters of the Rural and the Urban, the guest editors of this issue hosted two panels on the relationship of urban-based artists and their interest in rural topographies, aesthetics, and cultural practices.
- Full Text:
- Date Issued: 2019
Retrospective stock assessment of the Emperor red snapper (Lutjanus sebae) on the Seychelles Bank between 1977 and 2006
- Grandcourt, E M, Hecht, Thomas, Booth, Anthony J, Robinson, J
- Authors: Grandcourt, E M , Hecht, Thomas , Booth, Anthony J , Robinson, J
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125887 , vital:35829 , https://doi.10.1093/icesjms/fsn064
- Description: The Emperor red snapper, Lutjanus sebae, known as “Bourzwa” in the Seychelles, is distributed throughout the Indo-West Pacific from the southern Red Sea and East Africa to New Caledonia, north to Japan and south to Australia. It occurs near coral or rocky reefs and also over adjacent sand flats and gravel patches between 5 and 180 m deep (Allen, 1985; Anderson, 1986). Juveniles are frequently commensal with sea urchins (Kuiter and Tonozuka, 2001), and are found in nearshore, turbid waters (Williams and Russ, 1992), mangrove areas (Allen, 1985), and around coastal and offshore reefs (Williams and Russ, 1992). Larger L. sebae are generally found deeper, although they are also known to move into shallower water during winter (McPherson et al., 1988; Williams and Russ, 1992). Prey items include fish, crabs, other benthic crustaceans, and cephalopods. Lutjanus sebae is a large, long-lived species, attaining a maximum size of 116 cm fork length (McPherson and Squire, 1992) and maximum age of 34 years (Newman and Dunk, 2002). Despite an absence of data on its population structure, mixing, and identity, the population on the Seychelles Bank has been considered to be a unit stock for assessment purposes because of its remote location (e.g. Lablache and Carrara, 1988; Mees, 1992).
- Full Text:
- Date Issued: 2008
- Authors: Grandcourt, E M , Hecht, Thomas , Booth, Anthony J , Robinson, J
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125887 , vital:35829 , https://doi.10.1093/icesjms/fsn064
- Description: The Emperor red snapper, Lutjanus sebae, known as “Bourzwa” in the Seychelles, is distributed throughout the Indo-West Pacific from the southern Red Sea and East Africa to New Caledonia, north to Japan and south to Australia. It occurs near coral or rocky reefs and also over adjacent sand flats and gravel patches between 5 and 180 m deep (Allen, 1985; Anderson, 1986). Juveniles are frequently commensal with sea urchins (Kuiter and Tonozuka, 2001), and are found in nearshore, turbid waters (Williams and Russ, 1992), mangrove areas (Allen, 1985), and around coastal and offshore reefs (Williams and Russ, 1992). Larger L. sebae are generally found deeper, although they are also known to move into shallower water during winter (McPherson et al., 1988; Williams and Russ, 1992). Prey items include fish, crabs, other benthic crustaceans, and cephalopods. Lutjanus sebae is a large, long-lived species, attaining a maximum size of 116 cm fork length (McPherson and Squire, 1992) and maximum age of 34 years (Newman and Dunk, 2002). Despite an absence of data on its population structure, mixing, and identity, the population on the Seychelles Bank has been considered to be a unit stock for assessment purposes because of its remote location (e.g. Lablache and Carrara, 1988; Mees, 1992).
- Full Text:
- Date Issued: 2008
Revisiting nomenclature: 'Early Iron Age', 'First-Millennium Agriculturist', or what?
- Authors: Steele, John
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/934 , vital:30067
- Description: As an art historian who has recently become fascinated by First-Millennium Agriculturist ceramics, I have come across several attempts at dealing with an issue of appropriate nomenclature for desigrrating this era. Conceptual frameworks are articulated using words, yet an apparent discomfort with the term Early Iron Age has seemingly not led to a consistently used altemative. I have been wondering about this and, with respect, offer my thoughts on the matter in a hope that debate will be furthered. Hereunder I utilise aspects of the KwaZulu-Natal and Eastem Cape first millennium ceramic sequence to address some significances associated with such artefacts in interpretations of the past, and then discuss some ways in which ideas of particular social contexts are embedded in language. Thereafter introduction of the term Iron Age into South African archaeology is referred to with reference to past and current usage, and advantages/disadvantages of alternatives are suggested.
- Full Text:
- Date Issued: 2001
- Authors: Steele, John
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/934 , vital:30067
- Description: As an art historian who has recently become fascinated by First-Millennium Agriculturist ceramics, I have come across several attempts at dealing with an issue of appropriate nomenclature for desigrrating this era. Conceptual frameworks are articulated using words, yet an apparent discomfort with the term Early Iron Age has seemingly not led to a consistently used altemative. I have been wondering about this and, with respect, offer my thoughts on the matter in a hope that debate will be furthered. Hereunder I utilise aspects of the KwaZulu-Natal and Eastem Cape first millennium ceramic sequence to address some significances associated with such artefacts in interpretations of the past, and then discuss some ways in which ideas of particular social contexts are embedded in language. Thereafter introduction of the term Iron Age into South African archaeology is referred to with reference to past and current usage, and advantages/disadvantages of alternatives are suggested.
- Full Text:
- Date Issued: 2001
Rhodes University 1978 Graduation address
- Authors: Henderson, Derek Scott
- Date: 1978
- Language: English
- Type: Text
- Identifier: vital:7365 , http://hdl.handle.net/10962/d1017245
- Full Text:
- Date Issued: 1978
- Authors: Henderson, Derek Scott
- Date: 1978
- Language: English
- Type: Text
- Identifier: vital:7365 , http://hdl.handle.net/10962/d1017245
- Full Text:
- Date Issued: 1978
Rhodes University 1984 Graduation Ceremonies Address
- Authors: Henderson, Derek Scott
- Date: 1984
- Language: English
- Type: Text
- Identifier: vital:7464 , http://hdl.handle.net/10962/d1018341
- Full Text:
- Date Issued: 1984
- Authors: Henderson, Derek Scott
- Date: 1984
- Language: English
- Type: Text
- Identifier: vital:7464 , http://hdl.handle.net/10962/d1018341
- Full Text:
- Date Issued: 1984
Rhodes University Graduation Ceremony 1951
- Authors: Rhodes University
- Date: 1951
- Language: English
- Type: text
- Identifier: vital:8085 , http://hdl.handle.net/10962/d1004395
- Description: Rhodes University Inaugural Celebrations Programme. Special Graduation Ceremony, Grahamstown, Friday, 9th March, 1951. , Installation as Chancellor of the University of Dr. B. F. J. Schonland, C.B.E., LL.D., D.Sc., F.R.S., and Honorary Graduation Ceremony in the City Hall, Grahamstown, Thursday, October 25th, 1951, 11a.m.
- Full Text:
- Date Issued: 1951
- Authors: Rhodes University
- Date: 1951
- Language: English
- Type: text
- Identifier: vital:8085 , http://hdl.handle.net/10962/d1004395
- Description: Rhodes University Inaugural Celebrations Programme. Special Graduation Ceremony, Grahamstown, Friday, 9th March, 1951. , Installation as Chancellor of the University of Dr. B. F. J. Schonland, C.B.E., LL.D., D.Sc., F.R.S., and Honorary Graduation Ceremony in the City Hall, Grahamstown, Thursday, October 25th, 1951, 11a.m.
- Full Text:
- Date Issued: 1951
Rhodes University Graduation Ceremony 1999
- Authors: Rhodes University
- Date: 1999
- Language: English
- Type: text
- Identifier: vital:8133 , http://hdl.handle.net/10962/d1006778
- Description: Rhodes University 1999 Graduation Ceremonies [at] 1820 Settlers National Monument Friday, 9 April 1999 at 18:00 p.m. [and] 10 April 1999 at 10:30 a.m. , The Installation of Gert Johannes Gerwel as Chancellor of Rhodes University to be followed by a Graduation Ceremony 1820 Settlers National Monument Friday, 9 April 1999 at 10:30 a.m. , Rhodes University 1999 Graduation Ceremony City Hall, East London Friday, 7 May 1999 at 18:00 p.m.
- Full Text:
- Date Issued: 1999
- Authors: Rhodes University
- Date: 1999
- Language: English
- Type: text
- Identifier: vital:8133 , http://hdl.handle.net/10962/d1006778
- Description: Rhodes University 1999 Graduation Ceremonies [at] 1820 Settlers National Monument Friday, 9 April 1999 at 18:00 p.m. [and] 10 April 1999 at 10:30 a.m. , The Installation of Gert Johannes Gerwel as Chancellor of Rhodes University to be followed by a Graduation Ceremony 1820 Settlers National Monument Friday, 9 April 1999 at 10:30 a.m. , Rhodes University 1999 Graduation Ceremony City Hall, East London Friday, 7 May 1999 at 18:00 p.m.
- Full Text:
- Date Issued: 1999