Influence of grazing by large mammals on the spider community of a Kenyan savanna biome
- Warui, Charles M, Villet, Martin H, Young, T P, Jocqué, R
- Authors: Warui, Charles M , Villet, Martin H , Young, T P , Jocqué, R
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6889 , http://hdl.handle.net/10962/d1011649 , http://0-www.bioone.org.wam.seals.ac.za/doi/10.1636/CT05-43.1
- Full Text:
- Date Issued: 2005
- Authors: Warui, Charles M , Villet, Martin H , Young, T P , Jocqué, R
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6889 , http://hdl.handle.net/10962/d1011649 , http://0-www.bioone.org.wam.seals.ac.za/doi/10.1636/CT05-43.1
- Full Text:
- Date Issued: 2005
The great arch of unimagined bridges: integrative play therapy with an abused child
- Authors: McDermott, R
- Date: 2005
- Language: English
- Type: text , Article
- Identifier: vital:6272 , http://hdl.handle.net/10962/d1008272
- Description: This case study describes the early phases of integrative, long-term psychotherapy undertaken with a child subjected to chronic domestic trauma including violence, alcohol abuse, neglect, abandonment, and bereavement resulting from HIV/AIDS. Recent statistics on the prevalence of violent trauma, domestic abuse and HIV/AIDS in South Africa are reviewed, as are principles of trauma intervention that have been established across a range of psychotherapeutic modalities. Following from integrative trauma work undertaken locally, this therapeutic process acknowledges both indigenous and western frameworks of meaning, the latter most heavily informed by principles of analytical psychology. Selected aspects of the therapy are discussed in light of both perspectives, with reference to the child’s process of recovery. This paper seeks to add support to practised and published local work in which a range of possible healing practices, meanings, and experience are taken into account. It is proposed that such integrative efforts contribute towards an evolving African psychotherapy.
- Full Text:
- Date Issued: 2005
- Authors: McDermott, R
- Date: 2005
- Language: English
- Type: text , Article
- Identifier: vital:6272 , http://hdl.handle.net/10962/d1008272
- Description: This case study describes the early phases of integrative, long-term psychotherapy undertaken with a child subjected to chronic domestic trauma including violence, alcohol abuse, neglect, abandonment, and bereavement resulting from HIV/AIDS. Recent statistics on the prevalence of violent trauma, domestic abuse and HIV/AIDS in South Africa are reviewed, as are principles of trauma intervention that have been established across a range of psychotherapeutic modalities. Following from integrative trauma work undertaken locally, this therapeutic process acknowledges both indigenous and western frameworks of meaning, the latter most heavily informed by principles of analytical psychology. Selected aspects of the therapy are discussed in light of both perspectives, with reference to the child’s process of recovery. This paper seeks to add support to practised and published local work in which a range of possible healing practices, meanings, and experience are taken into account. It is proposed that such integrative efforts contribute towards an evolving African psychotherapy.
- Full Text:
- Date Issued: 2005
Towards an economic valuation of biodiversity: freshwater ecosystems
- Antrobus, Geoffrey G, Law, Matt
- Authors: Antrobus, Geoffrey G , Law, Matt
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143013 , vital:38185 , http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.620.4217andrep=rep1andtype=pdf
- Description: The valuation of environmental resources and biodiversity as a whole has become an increasingly necessary topic of research as our understanding of the importance and benefits of the healthy functioning of the environment develops. A major shortcoming of current research is that there has been very little advance in the valuation of freshwater biodiversity. The paper examines the socioeconomic importance of biodiversity and outlines the fundamentals of economic valuation thereof. The difficulties associated with the valuation of freshwater ecosystems are outlined and the results of a study presented to the South African Water Research Commission incorporating resource economics into freshwater quality objectives is described. The valuation of freshwater biodiversity is an important and complicated task that needs close attention in future research.
- Full Text:
- Date Issued: 2005
- Authors: Antrobus, Geoffrey G , Law, Matt
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143013 , vital:38185 , http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.620.4217andrep=rep1andtype=pdf
- Description: The valuation of environmental resources and biodiversity as a whole has become an increasingly necessary topic of research as our understanding of the importance and benefits of the healthy functioning of the environment develops. A major shortcoming of current research is that there has been very little advance in the valuation of freshwater biodiversity. The paper examines the socioeconomic importance of biodiversity and outlines the fundamentals of economic valuation thereof. The difficulties associated with the valuation of freshwater ecosystems are outlined and the results of a study presented to the South African Water Research Commission incorporating resource economics into freshwater quality objectives is described. The valuation of freshwater biodiversity is an important and complicated task that needs close attention in future research.
- Full Text:
- Date Issued: 2005
Wireless Network Visualization Using Radio Propagation Modelling
- Janse van Rensburg, Johanna, Irwin, Barry V W
- Authors: Janse van Rensburg, Johanna , Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428859 , vital:72541 , https://d1wqtxts1xzle7.cloudfront.net/81589186/Papers_5CJanse_van_Rensburg_Wireless_Radio_Prop-libre.pdf?1646243170=esponse-content-disposi-tion=inline%3B+filename%3DWireless_Network_Visualization_Using_Rad.pdfExpires=1714748958Signature=OF69CzUsXIaE9WuVUQ~p01LV8Fdm4EOpX1eudE3qomWEWQ9jngy36AuZ38dZEAfIhWWFgO7byMtmx8hOUE3uYjjqLLGziqWV05r~K2n~DdSHAO1x2omrK53ew3lSW2AJ677zsqOIcRb-yVr7kE2PbAw1QolptUWQVI2YpAHEKdg5EQXm2iAW~FrQ7ljJxuwZTKaVLoubxj4HRLwJxTPIS9iN9nHn3sNKyIojfG6duWnCQ0dpkIKiKWTY6HVioBQCiN1vSdLUagXnTeRthoOFGyfo2kd3XG1Pi3tttIwFviPCh5H1297BCpMruY-h6XjSnPBGgAG33dOnkClBFnyAKg__Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: Wireless technologies have had an enormous impact on networking in re-cent years. It can create new business oppurtunities and allow users to communicate and share data in a new fashion. Wireless Networks de-crease installation costs, reduce the deployment time of a network and overcome physical barrier problems inherent in wiring. Unfortunately this flexibility comes at a price. The deployment, installation and setup of a WLAN is not a simple task and a number of factors need to be considered. Wireless Networks are notorious for being insecure due to signal spill, ad-hoc unauthorized access points and varying encryption strengths and standards. RF (Radio Frequency) interference and physical barriers sup-press a signal. In addition the channel frequencies each access point will be using in order to provide maximum roaming but minimum inter access point interference need to be considered. It is a complex balancing act to take these factors into account while still maintaining coverage, perfor-mance and security requirements. In this paper the benefits and feasibility of a model will be discussed that will enable the network administrator to visualize the coverage footprint of their wireless network when the above factors are taken into consideration. The program will be able to predict the strength, propagation and unwanted spill of signals which could compro-mise the security of an organisation prior to the deployment of a WLAN. In addition the model will provide functionality to visualize a signal from audit data once the WLAN is operational. The end result will be a program that can aid in the configuration, installation and management of a secure WLAN.
- Full Text:
- Date Issued: 2005
- Authors: Janse van Rensburg, Johanna , Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428859 , vital:72541 , https://d1wqtxts1xzle7.cloudfront.net/81589186/Papers_5CJanse_van_Rensburg_Wireless_Radio_Prop-libre.pdf?1646243170=esponse-content-disposi-tion=inline%3B+filename%3DWireless_Network_Visualization_Using_Rad.pdfExpires=1714748958Signature=OF69CzUsXIaE9WuVUQ~p01LV8Fdm4EOpX1eudE3qomWEWQ9jngy36AuZ38dZEAfIhWWFgO7byMtmx8hOUE3uYjjqLLGziqWV05r~K2n~DdSHAO1x2omrK53ew3lSW2AJ677zsqOIcRb-yVr7kE2PbAw1QolptUWQVI2YpAHEKdg5EQXm2iAW~FrQ7ljJxuwZTKaVLoubxj4HRLwJxTPIS9iN9nHn3sNKyIojfG6duWnCQ0dpkIKiKWTY6HVioBQCiN1vSdLUagXnTeRthoOFGyfo2kd3XG1Pi3tttIwFviPCh5H1297BCpMruY-h6XjSnPBGgAG33dOnkClBFnyAKg__Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: Wireless technologies have had an enormous impact on networking in re-cent years. It can create new business oppurtunities and allow users to communicate and share data in a new fashion. Wireless Networks de-crease installation costs, reduce the deployment time of a network and overcome physical barrier problems inherent in wiring. Unfortunately this flexibility comes at a price. The deployment, installation and setup of a WLAN is not a simple task and a number of factors need to be considered. Wireless Networks are notorious for being insecure due to signal spill, ad-hoc unauthorized access points and varying encryption strengths and standards. RF (Radio Frequency) interference and physical barriers sup-press a signal. In addition the channel frequencies each access point will be using in order to provide maximum roaming but minimum inter access point interference need to be considered. It is a complex balancing act to take these factors into account while still maintaining coverage, perfor-mance and security requirements. In this paper the benefits and feasibility of a model will be discussed that will enable the network administrator to visualize the coverage footprint of their wireless network when the above factors are taken into consideration. The program will be able to predict the strength, propagation and unwanted spill of signals which could compro-mise the security of an organisation prior to the deployment of a WLAN. In addition the model will provide functionality to visualize a signal from audit data once the WLAN is operational. The end result will be a program that can aid in the configuration, installation and management of a secure WLAN.
- Full Text:
- Date Issued: 2005
Language rights, intercultural communication and the law in South Africa
- Kaschula, Russell H, Ralarala, Monwabisi K
- Authors: Kaschula, Russell H , Ralarala, Monwabisi K
- Date: 2004
- Subjects: Language policy -- South Africa , Courts interpreting and translating -- South Africa , Intercultural communication -- South Africa , Conduct of court proceedings -- South Africa , Linguistic rights -- South Africa , Multilingualism -- South Africa
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59434 , vital:27602 , https://doi.org/10.1080/02572117.2004.10587242
- Description: This article seeks to explore the present language scenario in courts of law. The article makes use of section 6 of the Constitution of the Republic of South Africa (1996), as a point of departure. At face value this section seems to entrench the language rights of individuals. This would mean that individuals could request trials to be held in their mother tongues, with fluent and competent speakers of that mother tongue sitting on the bench. However, this has not materialised. Contrary to popular opinion, the article argues that individual language rights are to some extent entrenched in the Constitution, but there are no mechanisms to secure such rights in the public domain. The article argues that it is often only language privileges that are preserved in institutions such as the justice system. Legally speaking, there is an obligation on the State to provide interpreters to facilitate access to all eleven official languages in courts of law. This in itself presents numerous challenges. The article argues further that the corollary to this is that there is very little space for intercultural communication in courts of law (as defined by Ting-Toomey, 1999, and Gibson, 2002). There has been little or no capacity building in this regard. It is English, to some extent Afrikaans, and the western cultural paradigm, which prevails. The result is further communication breakdown and language intolerance. In this article, the notion of language rights in courts of law is explored against the backdrop of existing theories of intercultural communication.
- Full Text:
- Date Issued: 2004
- Authors: Kaschula, Russell H , Ralarala, Monwabisi K
- Date: 2004
- Subjects: Language policy -- South Africa , Courts interpreting and translating -- South Africa , Intercultural communication -- South Africa , Conduct of court proceedings -- South Africa , Linguistic rights -- South Africa , Multilingualism -- South Africa
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59434 , vital:27602 , https://doi.org/10.1080/02572117.2004.10587242
- Description: This article seeks to explore the present language scenario in courts of law. The article makes use of section 6 of the Constitution of the Republic of South Africa (1996), as a point of departure. At face value this section seems to entrench the language rights of individuals. This would mean that individuals could request trials to be held in their mother tongues, with fluent and competent speakers of that mother tongue sitting on the bench. However, this has not materialised. Contrary to popular opinion, the article argues that individual language rights are to some extent entrenched in the Constitution, but there are no mechanisms to secure such rights in the public domain. The article argues that it is often only language privileges that are preserved in institutions such as the justice system. Legally speaking, there is an obligation on the State to provide interpreters to facilitate access to all eleven official languages in courts of law. This in itself presents numerous challenges. The article argues further that the corollary to this is that there is very little space for intercultural communication in courts of law (as defined by Ting-Toomey, 1999, and Gibson, 2002). There has been little or no capacity building in this regard. It is English, to some extent Afrikaans, and the western cultural paradigm, which prevails. The result is further communication breakdown and language intolerance. In this article, the notion of language rights in courts of law is explored against the backdrop of existing theories of intercultural communication.
- Full Text:
- Date Issued: 2004
Seasonal rates of parasitism of diamondback moth (Plutella xylostella) in subsistence cabbage crops in the Eastern Cape, South Africa
- Mkize, Nolwazi, Villet, Martin H
- Authors: Mkize, Nolwazi , Villet, Martin H
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/442807 , vital:74035 , ISBN , https://www.torrossa.com/en/resources/an/5063829#page=221
- Description: Smith's (personal communication) work in a continuous, commercial cabbage-growing area near Grahamstown showed that parasitism of diamondback moth averaged over 60% and could reach 100%. In many parts of the world cabbage crops are not under continuous cultivation, and periodic cropping Systems may demonstrate différent patterns of parasitism, especially in disrupted, patchy subsistence crops. Cabbage (Brassica oleracea) is the most commonly grown cruciferous crop in subsistence gardens in the suburbs of Grahamstown East. The subsistence farmers' crops are considered patchy because the cabbages are grown in small and relatively widely separated plots. Thèse gardens provided an opportunity to follow Talekar and Shelton's (1993) suggestion to investigate the population dynamics of P. xylostella (a useful model pest) and its rate of parasitism on cabbages of subsistence farmers where commercial pesticides are used less.
- Full Text:
- Date Issued: 2004
- Authors: Mkize, Nolwazi , Villet, Martin H
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/442807 , vital:74035 , ISBN , https://www.torrossa.com/en/resources/an/5063829#page=221
- Description: Smith's (personal communication) work in a continuous, commercial cabbage-growing area near Grahamstown showed that parasitism of diamondback moth averaged over 60% and could reach 100%. In many parts of the world cabbage crops are not under continuous cultivation, and periodic cropping Systems may demonstrate différent patterns of parasitism, especially in disrupted, patchy subsistence crops. Cabbage (Brassica oleracea) is the most commonly grown cruciferous crop in subsistence gardens in the suburbs of Grahamstown East. The subsistence farmers' crops are considered patchy because the cabbages are grown in small and relatively widely separated plots. Thèse gardens provided an opportunity to follow Talekar and Shelton's (1993) suggestion to investigate the population dynamics of P. xylostella (a useful model pest) and its rate of parasitism on cabbages of subsistence farmers where commercial pesticides are used less.
- Full Text:
- Date Issued: 2004
6-Hydroxymelatonin protects against cyanide induced oxidative stress in rat brain homogenates
- Maharaj, Deepa S, Walker, Roderick B, Glass, Beverley D, Daya, Santylal
- Authors: Maharaj, Deepa S , Walker, Roderick B , Glass, Beverley D , Daya, Santylal
- Date: 2003
- Language: English
- Type: Article , text
- Identifier: vital:6405 , http://hdl.handle.net/10962/d1006478
- Description: Both 6-hydroxymelatonin and N-acetyl-N-formyl-5-methoxykynurenamine are photodegradants and enzymatic metabolites of melatonin and are known to retain equipotent activity against potassium cyanide-induced superoxide generation compared to melatonin. It is not clear whether one or both of these metabolites is responsible for this effect. The present study therefore investigates the possible manner in which 6-hydroxymelatonin protects against oxidative stress induced by cyanide in rat brain homogenates. We examined the ability of 6-hydroxymelatonin to scavenge KCN-induced superoxide anion generation as well as lipid peroxidation. In addition, we also examined the effect of this indole on lactate dehydrogenase activity (LDH) as well as mitochondrial electron transport using dichlorophenol–indophenol as an electron acceptor. The results of this study show that 6-hydroxymelatonin significantly reduces KCN-induced superoxide anion generation, which is accompanied by a commensurate reduction in lipid peroxidation. Partial reversal of the KCN-induced reduction in mitochondrial electron transport is accompanied by a similar reversal of mitochondrial LDH activity blunted by KCN. It can thus be proposed that 6-hydroxymelatonin is potentially neuroprotective against KCN-induced neurotoxicity.
- Full Text:
- Date Issued: 2003
- Authors: Maharaj, Deepa S , Walker, Roderick B , Glass, Beverley D , Daya, Santylal
- Date: 2003
- Language: English
- Type: Article , text
- Identifier: vital:6405 , http://hdl.handle.net/10962/d1006478
- Description: Both 6-hydroxymelatonin and N-acetyl-N-formyl-5-methoxykynurenamine are photodegradants and enzymatic metabolites of melatonin and are known to retain equipotent activity against potassium cyanide-induced superoxide generation compared to melatonin. It is not clear whether one or both of these metabolites is responsible for this effect. The present study therefore investigates the possible manner in which 6-hydroxymelatonin protects against oxidative stress induced by cyanide in rat brain homogenates. We examined the ability of 6-hydroxymelatonin to scavenge KCN-induced superoxide anion generation as well as lipid peroxidation. In addition, we also examined the effect of this indole on lactate dehydrogenase activity (LDH) as well as mitochondrial electron transport using dichlorophenol–indophenol as an electron acceptor. The results of this study show that 6-hydroxymelatonin significantly reduces KCN-induced superoxide anion generation, which is accompanied by a commensurate reduction in lipid peroxidation. Partial reversal of the KCN-induced reduction in mitochondrial electron transport is accompanied by a similar reversal of mitochondrial LDH activity blunted by KCN. It can thus be proposed that 6-hydroxymelatonin is potentially neuroprotective against KCN-induced neurotoxicity.
- Full Text:
- Date Issued: 2003
Classroom talk: there are more questions than answers.
- Authors: Hendricks, Monica
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/469437 , vital:77242 , https://doi.org/10.2989/16073610309486326
- Description: Congruence between new language in education policies and broader curriculum policy is crucial if educational and language acquisition plans are to be realised, and wider social aims of access and equity are to be met. This study addresses the alignment between the language policy choice of Vuka primary school, and the classroom practices of an English and a Science teacher. My research interests were (i) to analyse classroom talk with respect to teachers' questions providing comprehensible input (Krashen, 1982) and learners' responses constituting comprehensible output (Swain, 1985); (ii) to establish whether there was congruence between national language in education policy (LiEP) and curriculum policy, on the one hand, and local school-level language policy and practices, on the other. My findings provide empirical evidence of alignment between the language policy of Vuka primary and the classroom language practices of an English and a Science teacher in Grades 5, 6 and 7.
- Full Text:
- Date Issued: 2003
- Authors: Hendricks, Monica
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/469437 , vital:77242 , https://doi.org/10.2989/16073610309486326
- Description: Congruence between new language in education policies and broader curriculum policy is crucial if educational and language acquisition plans are to be realised, and wider social aims of access and equity are to be met. This study addresses the alignment between the language policy choice of Vuka primary school, and the classroom practices of an English and a Science teacher. My research interests were (i) to analyse classroom talk with respect to teachers' questions providing comprehensible input (Krashen, 1982) and learners' responses constituting comprehensible output (Swain, 1985); (ii) to establish whether there was congruence between national language in education policy (LiEP) and curriculum policy, on the one hand, and local school-level language policy and practices, on the other. My findings provide empirical evidence of alignment between the language policy of Vuka primary and the classroom language practices of an English and a Science teacher in Grades 5, 6 and 7.
- Full Text:
- Date Issued: 2003
Life history traits of Bathyclarias nyasensis (Siluroidei) in Lake Malawi
- Authors: Kaunda, E , Hecht, Thomas
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446918 , vital:74570 , https://doi.org/10.1080/15627020.2003.11657193
- Description: Life history traits, including age, growth, reproduction and diet of Bathyclarias nyasensis from Lake Malawi were studied between December 1996 and November 1998. Owing to reabsorption of pectoral spines with increasing fish size, and the relatively low number of spines that could be aged reliably, only otoliths were used to age fish. The maximum age for B. nyasensis was estimated at 14 years. There was no difference in growth rate between males and females.
- Full Text:
- Date Issued: 2003
- Authors: Kaunda, E , Hecht, Thomas
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446918 , vital:74570 , https://doi.org/10.1080/15627020.2003.11657193
- Description: Life history traits, including age, growth, reproduction and diet of Bathyclarias nyasensis from Lake Malawi were studied between December 1996 and November 1998. Owing to reabsorption of pectoral spines with increasing fish size, and the relatively low number of spines that could be aged reliably, only otoliths were used to age fish. The maximum age for B. nyasensis was estimated at 14 years. There was no difference in growth rate between males and females.
- Full Text:
- Date Issued: 2003
Mandela's Long Walk to Freedom: the isiXhosa translator's tall order
- Authors: Mtuze, Peter T
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/468377 , vital:77049 , https://doi.org/10.2989/16073610309486337
- Description: The paper aims to show how the translator coped with transmitting the message to the new target audience bearing in mind Hilaire Belloc's six general rules for the translator of a prose text, as reflected in Bassnett-McGuire (1988: 116-117) which could be summarised as "translating the sense of the original, translating idiom by idiom, intention by intention, avoiding false friends, aiming at the resurrection of an alien thing in a native body, and not to embellish". These and many other principles will form the general background against which the current translation will be viewed. It should be stressed, from the outset, that the primary aim of the exercise was to highlight the various problems encountered in the search for equivalence or adequacy, not to evaluate the translation as such.
- Full Text:
- Date Issued: 2003
- Authors: Mtuze, Peter T
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/468377 , vital:77049 , https://doi.org/10.2989/16073610309486337
- Description: The paper aims to show how the translator coped with transmitting the message to the new target audience bearing in mind Hilaire Belloc's six general rules for the translator of a prose text, as reflected in Bassnett-McGuire (1988: 116-117) which could be summarised as "translating the sense of the original, translating idiom by idiom, intention by intention, avoiding false friends, aiming at the resurrection of an alien thing in a native body, and not to embellish". These and many other principles will form the general background against which the current translation will be viewed. It should be stressed, from the outset, that the primary aim of the exercise was to highlight the various problems encountered in the search for equivalence or adequacy, not to evaluate the translation as such.
- Full Text:
- Date Issued: 2003
The diet of a small group of extralimital giraffe
- Parker, Daniel M, Bernard, Ric T F, Colvin, S A
- Authors: Parker, Daniel M , Bernard, Ric T F , Colvin, S A
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6950 , http://hdl.handle.net/10962/d1011980
- Description: Giraffe are extralimital in the Eastern Cape Province, South Africa where recent local introductions have persisted despite limited research into their impact on the indigenous flora. The diet of 15 giraffe at the Shamwari Game Reserve was recorded by direct observation during summer (March/April) and winter (July/August) 2001, quantifying diet by frequency of occurrence (individual records scored and expressed as a percentage of the total). Preference indices were also calculated. Habitat use was measured by the number of hours giraffe fed in different habitats. The diet comprised of 14 plant species, the most important species being Rhus longispina (47.9%), Acacia karroo (25.7%) and Euclea undulata (17.6%). Importance of R. longispina, A. karroo and Tarchonanthus camphoratus fluctuated seasonally. Rhus longispina was more important in winter with a corresponding decrease in feeding on A. karroo. Tarchonanthus camphoratus was only consumed during summer. Acacia karroo thickets (previously disturbed areas) were utilized most (summer 12 h; winter 9 h), with alternative habitats utilized more often in winter than in summer. We suggest that the seasonal fluctuation in the importance of R. longispina & A. karroo reflects the deciduous nature of A. karroo.
- Full Text:
- Date Issued: 2003
- Authors: Parker, Daniel M , Bernard, Ric T F , Colvin, S A
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6950 , http://hdl.handle.net/10962/d1011980
- Description: Giraffe are extralimital in the Eastern Cape Province, South Africa where recent local introductions have persisted despite limited research into their impact on the indigenous flora. The diet of 15 giraffe at the Shamwari Game Reserve was recorded by direct observation during summer (March/April) and winter (July/August) 2001, quantifying diet by frequency of occurrence (individual records scored and expressed as a percentage of the total). Preference indices were also calculated. Habitat use was measured by the number of hours giraffe fed in different habitats. The diet comprised of 14 plant species, the most important species being Rhus longispina (47.9%), Acacia karroo (25.7%) and Euclea undulata (17.6%). Importance of R. longispina, A. karroo and Tarchonanthus camphoratus fluctuated seasonally. Rhus longispina was more important in winter with a corresponding decrease in feeding on A. karroo. Tarchonanthus camphoratus was only consumed during summer. Acacia karroo thickets (previously disturbed areas) were utilized most (summer 12 h; winter 9 h), with alternative habitats utilized more often in winter than in summer. We suggest that the seasonal fluctuation in the importance of R. longispina & A. karroo reflects the deciduous nature of A. karroo.
- Full Text:
- Date Issued: 2003
Aphid (Sitobion yakini) investigation shows thin-walled sieve tubes in barley (Hordeum vulgare L) to be more functional than thick-walled sieve tubes
- Matsiliza, Balbalwa, Botha, Christiaan E J
- Authors: Matsiliza, Balbalwa , Botha, Christiaan E J
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6526 , http://hdl.handle.net/10962/d1005960
- Description: Barley, like most other grasses that have been studied, contains two kinds of sieve tube. The first formed are called thinwalled sieve tubes because of their thin wall compared to the late-formed, and are associated with companion cells. The late-formed are thick-walled sieve tubes, which differentiate next to the metaxylem vessels and lack companion cells. Aphid (Sitobion yakini (Eastop) feeding was studied using light microscopy to determine if they preferentially feed from thin- or thick-walled sieve tubes in the barley leaf. Penetration of the stylets through the leaf epidermis and mesophyll was largely intercellular, becoming partly intercellular and, partly, intracellular inside the vascular bundle. Sixteen of 19 pairs of stylets (84%), and 293 of 317 (92%) stylet tracks terminated at the thin-walled sieve tubes, suggesting that Sitobion yakini feeds preferentially on the thin-walled sieve tubes which seem to be more attractive to the aphid. These thin-walled sieve tubes are thus probably the most functional in terms of phloem loading and transport.
- Full Text:
- Date Issued: 2002
- Authors: Matsiliza, Balbalwa , Botha, Christiaan E J
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6526 , http://hdl.handle.net/10962/d1005960
- Description: Barley, like most other grasses that have been studied, contains two kinds of sieve tube. The first formed are called thinwalled sieve tubes because of their thin wall compared to the late-formed, and are associated with companion cells. The late-formed are thick-walled sieve tubes, which differentiate next to the metaxylem vessels and lack companion cells. Aphid (Sitobion yakini (Eastop) feeding was studied using light microscopy to determine if they preferentially feed from thin- or thick-walled sieve tubes in the barley leaf. Penetration of the stylets through the leaf epidermis and mesophyll was largely intercellular, becoming partly intercellular and, partly, intracellular inside the vascular bundle. Sixteen of 19 pairs of stylets (84%), and 293 of 317 (92%) stylet tracks terminated at the thin-walled sieve tubes, suggesting that Sitobion yakini feeds preferentially on the thin-walled sieve tubes which seem to be more attractive to the aphid. These thin-walled sieve tubes are thus probably the most functional in terms of phloem loading and transport.
- Full Text:
- Date Issued: 2002
Asthenospheric and lithospheric sources for Mesozoic dolerites from Liberia (Africa): trace element and isotopic evidence
- Dupuy, C, Marsh, Julian S, Dostal, J, Michard, A, Testa, S
- Authors: Dupuy, C , Marsh, Julian S , Dostal, J , Michard, A , Testa, S
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140422 , vital:37887 , https://doi.org/10.1016/0012-821X(88)90067-2
- Description: Combined elemental, and Sr and Nd isotopic data are presented for Mesozoic dolerite dikes of Liberia (Africa) which are related to the initial stage of opening of the Atlantic Ocean.
- Full Text: false
- Date Issued: 2002
- Authors: Dupuy, C , Marsh, Julian S , Dostal, J , Michard, A , Testa, S
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140422 , vital:37887 , https://doi.org/10.1016/0012-821X(88)90067-2
- Description: Combined elemental, and Sr and Nd isotopic data are presented for Mesozoic dolerite dikes of Liberia (Africa) which are related to the initial stage of opening of the Atlantic Ocean.
- Full Text: false
- Date Issued: 2002
Geochemical constraints on coupled assimilation and fractional crystallization involving upper crustal compositions and continental tholeiitic magma
- Authors: Marsh, Julian S
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140432 , vital:37888 , https://doi.org/10.1016/0012-821X(89)90021-6
- Description: The commonly analyzed trace elements in tholeiites can be subdivided into three groups depending on their sense of enrichment or depletion in upper continental crust in relation to fractional crystallization. Lithophile incompatible elements are enriched in crustal rocks and by fractional crystallization, whereas compatible transition elements such as Ni and Cr are depleted. A small third group comprising Ti, V, Fe, and sometimes P, enrich with crystallization but are depleted in the crust.
- Full Text: false
- Date Issued: 2002
- Authors: Marsh, Julian S
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140432 , vital:37888 , https://doi.org/10.1016/0012-821X(89)90021-6
- Description: The commonly analyzed trace elements in tholeiites can be subdivided into three groups depending on their sense of enrichment or depletion in upper continental crust in relation to fractional crystallization. Lithophile incompatible elements are enriched in crustal rocks and by fractional crystallization, whereas compatible transition elements such as Ni and Cr are depleted. A small third group comprising Ti, V, Fe, and sometimes P, enrich with crystallization but are depleted in the crust.
- Full Text: false
- Date Issued: 2002
Behavioural interactions of predators and spawning chokka squid off South Africa: towards quantification
- Smale, Malcolm J, Sauer, Warwick H H, Roberts, Michael J
- Authors: Smale, Malcolm J , Sauer, Warwick H H , Roberts, Michael J
- Date: 2001
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123921 , vital:35516 , https://doi.10.1007/s002270100664
- Description: The interaction of a suite of predators with mating and spawning chokka squid (Loligo vulgaris reynaudii) was studied at inshore (<50 m) spawning grounds off South Africa. This study provides the first detailed records of predator–prey interactions of squids on their spawning grounds and is the first attempt to time disruptions caused by predators to the egg-laying behaviour of squids, thereby quantifying the perceived threat to the prey. The squids are focused on mate choice and reproduction while they aggregate over egg beds and they may be more vulnerable to predation than at other times. Their vulnerability to different predators in the field is examined and the tactics used against different predatory species are illustrated using recordings made with underwater video cameras. Predators recorded included two cephalopods (Octopus vulgaris and L. v. reynaudii), five teleosts (Pagellus bellotii natalensis, Spondyliosoma emarginatum, Pachymetopon aeneum, Cheimerius nufar and Pomatomus saltatrix), seven chondrichthyians (Squalus megalops, Mustelus mustelus, Carcharias taurus, Dasyatis brevicaudata, Gymnura natalensis, Poroderma africanum and P. pantherinum) and three marine mammals (Arctocephalus puscillus, Tursiops aduncus and Delphinus delphis). Analysis of behavioural interactions between predators and prey showed that predator disruption of egg laying may be quantified in terms of time. Marine mammals caused the most acute disruption, whereas other taxa had more chronic disruption effects because they spent more time on the spawning grounds. During November 1995, the suite of predators changed during the course of a 2-day period of underwater video recording, possibly because of an increase in water temperature. The hypothesis that predators would be concentrated around a spawning aggregation was tested by surveying the spawning ground using an underwater camera towed by a boat navigating with differential GPS. The results supported the hypothesis because predators were located only around the spawning sites. The serial spawning of chokka squids in recently upwelled water may reduce predation pressure. Furthermore, it may be difficult for predators to predict the specific spawning site on a particular day because squids disperse away from egg beds at night and use numerous spawning sites along the coast.
- Full Text:
- Date Issued: 2001
- Authors: Smale, Malcolm J , Sauer, Warwick H H , Roberts, Michael J
- Date: 2001
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123921 , vital:35516 , https://doi.10.1007/s002270100664
- Description: The interaction of a suite of predators with mating and spawning chokka squid (Loligo vulgaris reynaudii) was studied at inshore (<50 m) spawning grounds off South Africa. This study provides the first detailed records of predator–prey interactions of squids on their spawning grounds and is the first attempt to time disruptions caused by predators to the egg-laying behaviour of squids, thereby quantifying the perceived threat to the prey. The squids are focused on mate choice and reproduction while they aggregate over egg beds and they may be more vulnerable to predation than at other times. Their vulnerability to different predators in the field is examined and the tactics used against different predatory species are illustrated using recordings made with underwater video cameras. Predators recorded included two cephalopods (Octopus vulgaris and L. v. reynaudii), five teleosts (Pagellus bellotii natalensis, Spondyliosoma emarginatum, Pachymetopon aeneum, Cheimerius nufar and Pomatomus saltatrix), seven chondrichthyians (Squalus megalops, Mustelus mustelus, Carcharias taurus, Dasyatis brevicaudata, Gymnura natalensis, Poroderma africanum and P. pantherinum) and three marine mammals (Arctocephalus puscillus, Tursiops aduncus and Delphinus delphis). Analysis of behavioural interactions between predators and prey showed that predator disruption of egg laying may be quantified in terms of time. Marine mammals caused the most acute disruption, whereas other taxa had more chronic disruption effects because they spent more time on the spawning grounds. During November 1995, the suite of predators changed during the course of a 2-day period of underwater video recording, possibly because of an increase in water temperature. The hypothesis that predators would be concentrated around a spawning aggregation was tested by surveying the spawning ground using an underwater camera towed by a boat navigating with differential GPS. The results supported the hypothesis because predators were located only around the spawning sites. The serial spawning of chokka squids in recently upwelled water may reduce predation pressure. Furthermore, it may be difficult for predators to predict the specific spawning site on a particular day because squids disperse away from egg beds at night and use numerous spawning sites along the coast.
- Full Text:
- Date Issued: 2001
Spatial aspects of the reproductive and feeding biology of the striped robber, Brycinus lateralis (Pisces: Characidae), in the Okavango Delta, Botswana
- Booth, Anthony J, McKinlay, Bruce W
- Authors: Booth, Anthony J , McKinlay, Bruce W
- Date: 2001
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127020 , vital:35944 , https://doi.10.1080/15627020.2001.11657111
- Description: The Okavango Delta is a vast inland wetland system situated in northern Botswana. High rainfall is received in early summer in the southern Angolan highlands and throughout the Delta with the flood waters reaching the upper riverine floodplain between March and May where it percolates through to the lower drainage rivers between July and September. Aspects of the reproductive and feeding biology of two allopatric populations of the striped robber, Brycinus lateralis, a small characin species inhabiting the northern riverine floodplain and southern drainage rivers, were investigated. Both populations were similar in the biological aspects studied, with the flood cycle having little influence on the timing of reproduction, sexual maturity and dietary composition. Female fish from both populations matured sexually at 57mmSL, breeding over a protracted period during the warm, summer months. In both populations, the sex ratio was female-dominated at 4.8:1 (riverine floodplain) and 2.2:1 (drainage rivers). The striped robber is an opportunistic micro-carnivore with immature fish feeding predominantly on Daphnia spp. and adults being largely insectivorous.
- Full Text:
- Date Issued: 2001
- Authors: Booth, Anthony J , McKinlay, Bruce W
- Date: 2001
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127020 , vital:35944 , https://doi.10.1080/15627020.2001.11657111
- Description: The Okavango Delta is a vast inland wetland system situated in northern Botswana. High rainfall is received in early summer in the southern Angolan highlands and throughout the Delta with the flood waters reaching the upper riverine floodplain between March and May where it percolates through to the lower drainage rivers between July and September. Aspects of the reproductive and feeding biology of two allopatric populations of the striped robber, Brycinus lateralis, a small characin species inhabiting the northern riverine floodplain and southern drainage rivers, were investigated. Both populations were similar in the biological aspects studied, with the flood cycle having little influence on the timing of reproduction, sexual maturity and dietary composition. Female fish from both populations matured sexually at 57mmSL, breeding over a protracted period during the warm, summer months. In both populations, the sex ratio was female-dominated at 4.8:1 (riverine floodplain) and 2.2:1 (drainage rivers). The striped robber is an opportunistic micro-carnivore with immature fish feeding predominantly on Daphnia spp. and adults being largely insectivorous.
- Full Text:
- Date Issued: 2001
The relationship between subjective well-being and domain satisfactions in South Africa
- Authors: Moller, Valerie , Saris, W E
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:7116 , http://hdl.handle.net/10962/d1010749 , http://dx.doi.org/10.1023/A:1010851412273
- Description: This paper examines the relationship between subjective well-being and domain satisfactions. In the past different models have been specified. The most commonly applied model is the bottom-up model in which domain satisfactions affect subjective well-being. The more recent top-down model suggests a reversed relationship. Finally there is the supposition that the correlations between these variables can be spurious due to the effect of personality characteristics. Empirical research has shown that different models are found for different domains and in different countries. Focussing on the effects of the domain satisfactions of finances, housing and social contacts it has been found that subjective well-being is mainly affected by satisfaction with social contacts in Western developed countries and by satisfaction with finances in East European countries. The question we should like to answer in this study is whether a similar pattern obtains for the factors which influence subjective well-being among the different race groups in South Africa. Interestingly, coloured people and Asians did indeed show the expected effects but the groups with the most extreme living conditions did not. Evaluation of life circumstances by black and white South Africans was determined by expectations for the future rather than by current living conditions. This surprising result is discussed in the light of the political situation in South Africa.
- Full Text:
- Date Issued: 2001
- Authors: Moller, Valerie , Saris, W E
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:7116 , http://hdl.handle.net/10962/d1010749 , http://dx.doi.org/10.1023/A:1010851412273
- Description: This paper examines the relationship between subjective well-being and domain satisfactions. In the past different models have been specified. The most commonly applied model is the bottom-up model in which domain satisfactions affect subjective well-being. The more recent top-down model suggests a reversed relationship. Finally there is the supposition that the correlations between these variables can be spurious due to the effect of personality characteristics. Empirical research has shown that different models are found for different domains and in different countries. Focussing on the effects of the domain satisfactions of finances, housing and social contacts it has been found that subjective well-being is mainly affected by satisfaction with social contacts in Western developed countries and by satisfaction with finances in East European countries. The question we should like to answer in this study is whether a similar pattern obtains for the factors which influence subjective well-being among the different race groups in South Africa. Interestingly, coloured people and Asians did indeed show the expected effects but the groups with the most extreme living conditions did not. Evaluation of life circumstances by black and white South Africans was determined by expectations for the future rather than by current living conditions. This surprising result is discussed in the light of the political situation in South Africa.
- Full Text:
- Date Issued: 2001
Working conditions agreement for SACCAWU employees
- SACCAWU
- Authors: SACCAWU
- Date: 2001
- Subjects: SACCAWU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/175924 , vital:42641
- Description: As a SACCAWU Staff Member it is important to know exactly what your Conditions of Service are hence this booklet. The Union believes in the principle of good and fair treatment of Staff and sees this as encouraging motivated and dedicated Officials. We have therefore tried to make Conditions as favourable as possible within the constraints of being a no-profit making organisation. In return, however the organisation does expect diligence, commitment and efficiency. Staff have the right before 1st March, every year to put forward proposals to* National Finance Committee in order to improve Working Conditions. Two Representatives elected from each Region will attend National Discussions/Engagements which shall put together a national mandate and elect Representatives to meet with NFC.
- Full Text:
- Date Issued: 2001
- Authors: SACCAWU
- Date: 2001
- Subjects: SACCAWU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/175924 , vital:42641
- Description: As a SACCAWU Staff Member it is important to know exactly what your Conditions of Service are hence this booklet. The Union believes in the principle of good and fair treatment of Staff and sees this as encouraging motivated and dedicated Officials. We have therefore tried to make Conditions as favourable as possible within the constraints of being a no-profit making organisation. In return, however the organisation does expect diligence, commitment and efficiency. Staff have the right before 1st March, every year to put forward proposals to* National Finance Committee in order to improve Working Conditions. Two Representatives elected from each Region will attend National Discussions/Engagements which shall put together a national mandate and elect Representatives to meet with NFC.
- Full Text:
- Date Issued: 2001
Intertidal population structure of the edible mollusc Turbo sarmaticus (Vetigastropoda) at an unexploited and exploited sites along the coast of the Eastern Cape Province, South Africa
- Foster, Gregory G, Hodgson, Alan N
- Authors: Foster, Gregory G , Hodgson, Alan N
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447403 , vital:74622 , https://doi.org/10.1080/15627020.2000.11657088
- Description: The intertidal population structure of the large edible gastropod Turbo sarmaticus was examined at four sites along the Eastern Cape Province of South Africa. One site was free from exploitation, two were subjected to low levels of exploitationand one was heavily exploited. Within the intertidal zone at all sites there was a size-related distribution, with smalleranimals being found towards the upper mid-shore and larger animals occurring in a downshore direction. The mean shore densities (1.2–animals/m2) and biomass (4.4–9.4 g/m2) of T. sarmaticus at the sites where there was no, or minimal, exploitation of animals were not significantly different (P0.001). However, the largest animals (up to 110mmshell length) were found at the unexploited site, an offshore island. The lowest density (0.2 animals/m2) and biomass (0.4 g/m2) of T. sarmaticus was recorded at the site where the exploitation of this gastropod was intense. In addition, no animals of a legally exploitable size (>70 mm shell length) were found. It is suggested that intense over-exploitation is threatening the population at this site.
- Full Text:
- Date Issued: 2000
- Authors: Foster, Gregory G , Hodgson, Alan N
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447403 , vital:74622 , https://doi.org/10.1080/15627020.2000.11657088
- Description: The intertidal population structure of the large edible gastropod Turbo sarmaticus was examined at four sites along the Eastern Cape Province of South Africa. One site was free from exploitation, two were subjected to low levels of exploitationand one was heavily exploited. Within the intertidal zone at all sites there was a size-related distribution, with smalleranimals being found towards the upper mid-shore and larger animals occurring in a downshore direction. The mean shore densities (1.2–animals/m2) and biomass (4.4–9.4 g/m2) of T. sarmaticus at the sites where there was no, or minimal, exploitation of animals were not significantly different (P0.001). However, the largest animals (up to 110mmshell length) were found at the unexploited site, an offshore island. The lowest density (0.2 animals/m2) and biomass (0.4 g/m2) of T. sarmaticus was recorded at the site where the exploitation of this gastropod was intense. In addition, no animals of a legally exploitable size (>70 mm shell length) were found. It is suggested that intense over-exploitation is threatening the population at this site.
- Full Text:
- Date Issued: 2000
Phloem loading in the sucrose-export-defective (SXD-1) mutant maize is limited by callose deposition at plasmodesmata in bundle sheath-vascular parenchyma interface
- Botha, Christiaan E J, Cross, Robin H M, Van Bel, A J E, Peter, Craig I
- Authors: Botha, Christiaan E J , Cross, Robin H M , Van Bel, A J E , Peter, Craig I
- Date: 2000
- Language: English
- Type: Article
- Identifier: vital:6503 , http://hdl.handle.net/10962/d1005926
- Description: Using Lucifer Yellow we have demonstrated that the phloem-loading pathway from the mesophyll to the bundle sheath-vascular parenchyma interface in Zea mays source leaves follows a symplasmic route in small and intermediate vascular bundles in control as well as in the green sections of mutant sucrose-export-defective (SXD-1) plants. In the anthocyanin-rich mutant leaf sections, Lucifer Yellow transport was prohibited along the same path, at the bundle sheath-vascular parenchyma interface in particular. Plasmodesmata at the latter interface in SXD-1 anthocyanin-rich leaf sections appear to be structurally altered through callose deposition at the plasmodesmal orifices. We suggest that a transport bottleneck at the bundle sheath-vascular parenchyma interface is thus orchestrated and regulated through callose formation, preventing symplasmic transport across this important loading interface.
- Full Text:
- Date Issued: 2000
- Authors: Botha, Christiaan E J , Cross, Robin H M , Van Bel, A J E , Peter, Craig I
- Date: 2000
- Language: English
- Type: Article
- Identifier: vital:6503 , http://hdl.handle.net/10962/d1005926
- Description: Using Lucifer Yellow we have demonstrated that the phloem-loading pathway from the mesophyll to the bundle sheath-vascular parenchyma interface in Zea mays source leaves follows a symplasmic route in small and intermediate vascular bundles in control as well as in the green sections of mutant sucrose-export-defective (SXD-1) plants. In the anthocyanin-rich mutant leaf sections, Lucifer Yellow transport was prohibited along the same path, at the bundle sheath-vascular parenchyma interface in particular. Plasmodesmata at the latter interface in SXD-1 anthocyanin-rich leaf sections appear to be structurally altered through callose deposition at the plasmodesmal orifices. We suggest that a transport bottleneck at the bundle sheath-vascular parenchyma interface is thus orchestrated and regulated through callose formation, preventing symplasmic transport across this important loading interface.
- Full Text:
- Date Issued: 2000