Estimating the potential role of commercial over-harvesting in resource viability: A case study of five useful tree species in South Africa
- Shackleton, Charlie M, Guthrie, G, Main, R
- Authors: Shackleton, Charlie M , Guthrie, G , Main, R
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181324 , vital:43719 , xlink:href="https://doi.org/10.1002/ldr.652"
- Description: There is a growing commercialization of non-timber forest products (NTFPs) as a means of livelihood by rural communities throughout the developing world. This often occurs in the absence of any clear understanding of or guidelines regarding sustainable yields and ecological impacts, which may undermine the success of NTFP enterprises, especially from arid regions. This paper reports on the use of size class profiles and three quantitative indices to examine population profiles of five potentially useful tree species used as NTFPs in the semiarid lowveld of South Africa. We also contrast the population densities of the five tree species in 2003 with data from 1992. Low stem densities and population profiles indicated that three of the five species would preclude the establishment of NTFP enterprises based on their products. The other two species seem to have sufficient densities for some harvesting to take place, within an adaptive management framework. However, the longitudinal data indicated that the density of both these species had significantly declined over an eleven-year period, highlighting the need for appropriate management institutions. Additionally, the proportion of mature stems cut, and the degree of cutting per stem, had increased for all five species over the eleven years. The three quantitative indices of population stability were not correlated with one another, and hence provided a useful suite of measures sensitive to different aspects of size class profiles and their interpretation.
- Full Text:
- Date Issued: 2005
- Authors: Shackleton, Charlie M , Guthrie, G , Main, R
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181324 , vital:43719 , xlink:href="https://doi.org/10.1002/ldr.652"
- Description: There is a growing commercialization of non-timber forest products (NTFPs) as a means of livelihood by rural communities throughout the developing world. This often occurs in the absence of any clear understanding of or guidelines regarding sustainable yields and ecological impacts, which may undermine the success of NTFP enterprises, especially from arid regions. This paper reports on the use of size class profiles and three quantitative indices to examine population profiles of five potentially useful tree species used as NTFPs in the semiarid lowveld of South Africa. We also contrast the population densities of the five tree species in 2003 with data from 1992. Low stem densities and population profiles indicated that three of the five species would preclude the establishment of NTFP enterprises based on their products. The other two species seem to have sufficient densities for some harvesting to take place, within an adaptive management framework. However, the longitudinal data indicated that the density of both these species had significantly declined over an eleven-year period, highlighting the need for appropriate management institutions. Additionally, the proportion of mature stems cut, and the degree of cutting per stem, had increased for all five species over the eleven years. The three quantitative indices of population stability were not correlated with one another, and hence provided a useful suite of measures sensitive to different aspects of size class profiles and their interpretation.
- Full Text:
- Date Issued: 2005
Evaluating parts-of-speech taggers for use in a text-to-scene conversion system
- Glass, Kevin R, Bangay, Shaun D
- Authors: Glass, Kevin R , Bangay, Shaun D
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432654 , vital:72890 , https://www.cs.ru.ac.za/research/groups/vrsig/currentprojects/053texttoscene/paper01.pdf
- Description: This paper presents parts-of-speech tagging as a first step towards an autonomous text-to-scene conversion system. It categorizes some freely available taggers, according to the techniques used by each in order to automatically identify word-classes. In addition, the performance of each identified tagger is verified experimentally. The SUSANNE corpus is used for testing and reveals the complexity of working with different tagsets, resulting in substantially lower accuracies in our tests than in those reported by the developers of each tagger. The taggers are then grouped to form a voting system to attempt to raise accuracies, but in no cases do the combined results improve upon the individual accuracies. Additionally a new metric, agreement, is tentatively proposed as an indication of confidence in the output of a group of taggers where such output cannot be validated.
- Full Text:
- Date Issued: 2005
- Authors: Glass, Kevin R , Bangay, Shaun D
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432654 , vital:72890 , https://www.cs.ru.ac.za/research/groups/vrsig/currentprojects/053texttoscene/paper01.pdf
- Description: This paper presents parts-of-speech tagging as a first step towards an autonomous text-to-scene conversion system. It categorizes some freely available taggers, according to the techniques used by each in order to automatically identify word-classes. In addition, the performance of each identified tagger is verified experimentally. The SUSANNE corpus is used for testing and reveals the complexity of working with different tagsets, resulting in substantially lower accuracies in our tests than in those reported by the developers of each tagger. The taggers are then grouped to form a voting system to attempt to raise accuracies, but in no cases do the combined results improve upon the individual accuracies. Additionally a new metric, agreement, is tentatively proposed as an indication of confidence in the output of a group of taggers where such output cannot be validated.
- Full Text:
- Date Issued: 2005
Five unpublished coins of Alexander the great and his successors in the Rhodes University collection
- Snowball, Jeanette D, Snowball, Warren D
- Authors: Snowball, Jeanette D , Snowball, Warren D
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70359 , vital:29648 , http://dx.doi.org/10.7445/50-0-73
- Description: The article briefly discusses the economic and political significance of the Alexander III(“the Great”) type silver tetradrachm and publishes three of his coins currently held by the Rhodes University Classics Museum. Based on stylistic elements, they are classified as from the Amphipolis and Arados mints and were probably minted during his lifetime. Two further tetradrachms from the empires of Alexander’s successors, Ptolemy II and Seleucus IV, are also published.
- Full Text:
- Date Issued: 2005
Five unpublished coins of Alexander the great and his successors in the Rhodes University collection
- Authors: Snowball, Jeanette D , Snowball, Warren D
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70359 , vital:29648 , http://dx.doi.org/10.7445/50-0-73
- Description: The article briefly discusses the economic and political significance of the Alexander III(“the Great”) type silver tetradrachm and publishes three of his coins currently held by the Rhodes University Classics Museum. Based on stylistic elements, they are classified as from the Amphipolis and Arados mints and were probably minted during his lifetime. Two further tetradrachms from the empires of Alexander’s successors, Ptolemy II and Seleucus IV, are also published.
- Full Text:
- Date Issued: 2005
Harnessing newsroom knowledge:
- Authors: Berger, Guy
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159244 , vital:40280 , https://hdl.handle.net/10520/EJC146387
- Description: Nairobi's Nation newspaper has a sophisticated content management system (CMS); Grahamstown's Grocott's Mail has a patchwork of paper and computer tech. In Harare, the Mirror and the Independent newspapers fall somewhere in between. But what all of them lack is a way to use information communication technologies for knowledge management.
- Full Text:
- Date Issued: 2005
- Authors: Berger, Guy
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159244 , vital:40280 , https://hdl.handle.net/10520/EJC146387
- Description: Nairobi's Nation newspaper has a sophisticated content management system (CMS); Grahamstown's Grocott's Mail has a patchwork of paper and computer tech. In Harare, the Mirror and the Independent newspapers fall somewhere in between. But what all of them lack is a way to use information communication technologies for knowledge management.
- Full Text:
- Date Issued: 2005
Hydrogen peroxide oxidation of 2-chlorophenol and 2, 4, 5-trichlorophenol catalyzed by monomeric and aggregated cobalt tetrasulfophthalocyanine
- Agboola, Bolade, Ozoemena, Kenneth I, Nyokong, Tebello
- Authors: Agboola, Bolade , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289249 , vital:56612 , xlink:href="https://doi.org/10.1016/j.molcata.2004.10.041"
- Description: Cobalt tetrasulfophthalocyanine (CoTSPc) was used to catalyze the oxidation of 2-chlorophenol (2-CP) and 2,4,5-trichlorophenol (TCP) using hydrogen peroxide (H2O2) as the oxidant. This CoTSPc catalyzed hydrogen peroxide oxidation of chlorophenols resulted in the formation of different types of oxidation products depending on the solvent conditions. In water/methanol conditions (where CoTSPc is mainly monomeric, and unionized forms of the phenols), phenol and hydroquinone were the main oxidation products, while in phosphate buffer solutions (pH 7 and 10 for TCP and 2-CP, respectively, where CoTSPc is mainly aggregated, and ionized forms of the phenols), benzoquinone was the main product. In contrast to CoTSPc, other MTSPc complexes studied (AlTSPc, CuTSPc and NiTSPc) exhibited no detectable catalytic effect on the oxidation of chlorophenols under the experimental conditions employed, thus proving the effect of the central metal ions on efficient catalysis of chlorophenol. Reaction pathways are proposed based on the relative time of oxidation products formation.
- Full Text:
- Date Issued: 2005
- Authors: Agboola, Bolade , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289249 , vital:56612 , xlink:href="https://doi.org/10.1016/j.molcata.2004.10.041"
- Description: Cobalt tetrasulfophthalocyanine (CoTSPc) was used to catalyze the oxidation of 2-chlorophenol (2-CP) and 2,4,5-trichlorophenol (TCP) using hydrogen peroxide (H2O2) as the oxidant. This CoTSPc catalyzed hydrogen peroxide oxidation of chlorophenols resulted in the formation of different types of oxidation products depending on the solvent conditions. In water/methanol conditions (where CoTSPc is mainly monomeric, and unionized forms of the phenols), phenol and hydroquinone were the main oxidation products, while in phosphate buffer solutions (pH 7 and 10 for TCP and 2-CP, respectively, where CoTSPc is mainly aggregated, and ionized forms of the phenols), benzoquinone was the main product. In contrast to CoTSPc, other MTSPc complexes studied (AlTSPc, CuTSPc and NiTSPc) exhibited no detectable catalytic effect on the oxidation of chlorophenols under the experimental conditions employed, thus proving the effect of the central metal ions on efficient catalysis of chlorophenol. Reaction pathways are proposed based on the relative time of oxidation products formation.
- Full Text:
- Date Issued: 2005
Imbhola yesiXhosa traditional Xhosa cosmetics:
- Cocks, Michelle L, Dold, Anthony P
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141370 , vital:37966 , http://pza.sanbi.org/sites/default/files/info_library/imbhola_yesixhosa_pdf.pdf
- Description: Plants have been used for cosmetic purposes since time immemorial. The earliest known cosmetics come from the First Dynasty of Egypt, about 3100-2907 BC. Since the ancient Egyptians who used olive oil perfumed with aromatic plants to keep their skin supple, humans have been using plant extracts for cleansing and beautifying purposes.
- Full Text:
- Date Issued: 2005
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141370 , vital:37966 , http://pza.sanbi.org/sites/default/files/info_library/imbhola_yesixhosa_pdf.pdf
- Description: Plants have been used for cosmetic purposes since time immemorial. The earliest known cosmetics come from the First Dynasty of Egypt, about 3100-2907 BC. Since the ancient Egyptians who used olive oil perfumed with aromatic plants to keep their skin supple, humans have been using plant extracts for cleansing and beautifying purposes.
- Full Text:
- Date Issued: 2005
Immobilized cobalt (II) phthalocyanine–cobalt (II) porphyrin pentamer at a glassy carbon electrode
- Ozoemena, Kenneth I, Zhao, Zhixin, Nyokong, Tebello
- Authors: Ozoemena, Kenneth I , Zhao, Zhixin , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300322 , vital:57916 , xlink:href="https://doi.org/10.1016/j.elecom.2005.04.019"
- Description: This communication describes the electrochemistry of a novel cobalt phthalocyanine–cobalt porphyrin (cobalt(II)phthalocyanine–cobalt(II)tetra(5-phenoxy-10,15,20-triphenylporphyrin)) (CoPc-(CoTPP)4) immobilised onto a glassy carbon electrode (GCE). The GCE-CoPc-(CoTPP)4 displayed high efficiency as a potential amperometric sensor for hydrogen peroxide (H2O2) in neutral and alkaline pH conditions. Electrochemical and electrocatalytic properties of the pentamer seem to depend mostly on the central CoPc, and partly, on the synergistic effect of the CoPc/CoPP units. The GCE-CoPc-(CoTPP)4 showed very fast amperometric response (∼1 s), with linearities up to ⩾1.50 mM, low detection limits (μM range) and stability (8 weeks) towards the amperometric determination of laboratory and medical solutions of H2O2.
- Full Text:
- Date Issued: 2005
- Authors: Ozoemena, Kenneth I , Zhao, Zhixin , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300322 , vital:57916 , xlink:href="https://doi.org/10.1016/j.elecom.2005.04.019"
- Description: This communication describes the electrochemistry of a novel cobalt phthalocyanine–cobalt porphyrin (cobalt(II)phthalocyanine–cobalt(II)tetra(5-phenoxy-10,15,20-triphenylporphyrin)) (CoPc-(CoTPP)4) immobilised onto a glassy carbon electrode (GCE). The GCE-CoPc-(CoTPP)4 displayed high efficiency as a potential amperometric sensor for hydrogen peroxide (H2O2) in neutral and alkaline pH conditions. Electrochemical and electrocatalytic properties of the pentamer seem to depend mostly on the central CoPc, and partly, on the synergistic effect of the CoPc/CoPP units. The GCE-CoPc-(CoTPP)4 showed very fast amperometric response (∼1 s), with linearities up to ⩾1.50 mM, low detection limits (μM range) and stability (8 weeks) towards the amperometric determination of laboratory and medical solutions of H2O2.
- Full Text:
- Date Issued: 2005
In-kernel cryptographic executable verification
- Motara, Yusuf, M, Irwin, Barry V W
- Authors: Motara, Yusuf, M , Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429049 , vital:72556 , https://doi.org/10.1007/0-387-31163-7_25
- Description: This paper discusses the problems posed by Trojan horses and unauthorized code, and reviews existing solutions for dealing with them. A technique involving the in-kernel verification of executables is proposed. Its advantages include simplicity, transparency, ease of use and minimal setup time. In addition, the technique has several applications, including assisting with honeypot implementations, incident response and forensic investigations.
- Full Text:
- Date Issued: 2005
- Authors: Motara, Yusuf, M , Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429049 , vital:72556 , https://doi.org/10.1007/0-387-31163-7_25
- Description: This paper discusses the problems posed by Trojan horses and unauthorized code, and reviews existing solutions for dealing with them. A technique involving the in-kernel verification of executables is proposed. Its advantages include simplicity, transparency, ease of use and minimal setup time. In addition, the technique has several applications, including assisting with honeypot implementations, incident response and forensic investigations.
- Full Text:
- Date Issued: 2005
In-kernel cryptographic executable verification
- Motara, Yusuf, M, Irwin, Barry V W
- Authors: Motara, Yusuf, M , Irwin, Barry V W
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429937 , vital:72653 , https://doi.org/10.1007/0-387-31163-7_25
- Description: This paper discusses the problems posed by Trojan horses and unau-thorized code, and reviews existing solutions for dealing with them. A technique involving the in-kernel verification of executables is pro-posed. Its advantages include simplicity, transparency, ease of use and minimal setup time. In addition, the technique has several applications, including assisting with honeypot implementations, incident response and forensic investigations.
- Full Text:
- Date Issued: 2005
- Authors: Motara, Yusuf, M , Irwin, Barry V W
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429937 , vital:72653 , https://doi.org/10.1007/0-387-31163-7_25
- Description: This paper discusses the problems posed by Trojan horses and unau-thorized code, and reviews existing solutions for dealing with them. A technique involving the in-kernel verification of executables is pro-posed. Its advantages include simplicity, transparency, ease of use and minimal setup time. In addition, the technique has several applications, including assisting with honeypot implementations, incident response and forensic investigations.
- Full Text:
- Date Issued: 2005
Language is culture:
- Authors: Malila, Vanessa
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159256 , vital:40281 , https://hdl.handle.net/10520/EJC146402
- Description: Many of us think that English dominates the web pages we surf each day. Indeed, until recently English was the predominant language for publishing online, but things are slowly changing and the presence of linguistic diversity on the Internet is starting to become a reality in the global village. The question, however, remains: how many African languages are represented in that diversity?.
- Full Text:
- Date Issued: 2005
- Authors: Malila, Vanessa
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159256 , vital:40281 , https://hdl.handle.net/10520/EJC146402
- Description: Many of us think that English dominates the web pages we surf each day. Indeed, until recently English was the predominant language for publishing online, but things are slowly changing and the presence of linguistic diversity on the Internet is starting to become a reality in the global village. The question, however, remains: how many African languages are represented in that diversity?.
- Full Text:
- Date Issued: 2005
Life history of the springhare (Pedetes capensis) from a strongly seasonal environment in the Eastern Cape Province of South Africa
- Peinke, Dean, Bernard, Ric T F
- Authors: Peinke, Dean , Bernard, Ric T F
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447089 , vital:74583 , doi.org/10.1080/15627020.2005.11407327
- Description: The life history of the springhare (Pedetes capensis, Forster, 1778) at 33°S, in the Eastern Cape Province of South Africa, was characterized by continuous, aseasonal and asynchronous reproduction. Females were monotocous and consecutive pregnancies were separated by a non pregnant period (30–50 days) similar in length to the period of lactation. Young were relatively large at birth (8% of adult body weight) but were altricial and only emerged from the burrow at weaning. Towards the end of lactation, many females mated again (20% of all females were both lactating and in early pregnancy) and annual fecundity was probably two but never more than three. For a rodent, albeit a large one, this is a very slow rate of reproduction and we propose that the ricochetal locomotion (jumping on the hind legs) and semi-fossorial life style of the springhare will have resulted in decreased juvenile and adult mortality, and increased longevity, and that these factors have shaped the evolution of the life history of the springhare.
- Full Text:
- Date Issued: 2005
- Authors: Peinke, Dean , Bernard, Ric T F
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447089 , vital:74583 , doi.org/10.1080/15627020.2005.11407327
- Description: The life history of the springhare (Pedetes capensis, Forster, 1778) at 33°S, in the Eastern Cape Province of South Africa, was characterized by continuous, aseasonal and asynchronous reproduction. Females were monotocous and consecutive pregnancies were separated by a non pregnant period (30–50 days) similar in length to the period of lactation. Young were relatively large at birth (8% of adult body weight) but were altricial and only emerged from the burrow at weaning. Towards the end of lactation, many females mated again (20% of all females were both lactating and in early pregnancy) and annual fecundity was probably two but never more than three. For a rodent, albeit a large one, this is a very slow rate of reproduction and we propose that the ricochetal locomotion (jumping on the hind legs) and semi-fossorial life style of the springhare will have resulted in decreased juvenile and adult mortality, and increased longevity, and that these factors have shaped the evolution of the life history of the springhare.
- Full Text:
- Date Issued: 2005
Mainstreaming Gender Standards in Collective Bargaining
- COSATU
- Authors: COSATU
- Date: 2005
- Subjects: COSATU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/154231 , vital:39624
- Description: The apartheid system and capitalism used the patriarchal nature of the South African society through the sexual division of labour and divided the labour force on the grounds of class, race and gender to exploit them for cheap labour to maximize their profits. They exploited the notion of men as the head of the family to force men to become migrant labourers and disregarded the reproductive and domestic role of women.
- Full Text:
- Date Issued: 2005
- Authors: COSATU
- Date: 2005
- Subjects: COSATU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/154231 , vital:39624
- Description: The apartheid system and capitalism used the patriarchal nature of the South African society through the sexual division of labour and divided the labour force on the grounds of class, race and gender to exploit them for cheap labour to maximize their profits. They exploited the notion of men as the head of the family to force men to become migrant labourers and disregarded the reproductive and domestic role of women.
- Full Text:
- Date Issued: 2005
Marine Reserves: a guide to science, design, and use
- Authors: Booth, Anthony J
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124965 , vital:35714 , https://doi.10.2989/16085910509503862
- Description: With the considerable pressures that are being placed on our marine resources, there is an urgent need to find alternative strategies to ensure their long-term sustainability. One measure that has been proposed, and which is rapidly gaining popularity, is the designation of Marine Protected Area (MPA). These are demarcated areas that prohibit (or at least restrict) consumptive or extractive uses, such that human interferences and impacts are minimised. In this edited collection of papers, most of which have been written or co-written by the authors themselves, Sobel and Dahlgren have presented an excellent synopsis of the rationale behind, and the scientific basis underpinning, the use of marine reserves as a management tool. In addition, they have devoted half the book to the provision of case studies.
- Full Text:
- Date Issued: 2005
- Authors: Booth, Anthony J
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124965 , vital:35714 , https://doi.10.2989/16085910509503862
- Description: With the considerable pressures that are being placed on our marine resources, there is an urgent need to find alternative strategies to ensure their long-term sustainability. One measure that has been proposed, and which is rapidly gaining popularity, is the designation of Marine Protected Area (MPA). These are demarcated areas that prohibit (or at least restrict) consumptive or extractive uses, such that human interferences and impacts are minimised. In this edited collection of papers, most of which have been written or co-written by the authors themselves, Sobel and Dahlgren have presented an excellent synopsis of the rationale behind, and the scientific basis underpinning, the use of marine reserves as a management tool. In addition, they have devoted half the book to the provision of case studies.
- Full Text:
- Date Issued: 2005
Melatonin generates singlet oxygen on laser irradiation but acts as a quencher when irradiated by lamp photolysis
- Maharaj, Deepa S, Molell, H, Antunes, Edith M, Maharaj, Hiren, Maree, D M, Nyokong, Tebello, Glass, Beverley D, Daya, Santy
- Authors: Maharaj, Deepa S , Molell, H , Antunes, Edith M , Maharaj, Hiren , Maree, D M , Nyokong, Tebello , Glass, Beverley D , Daya, Santy
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300335 , vital:57917 , xlink:href="https://doi.org/10.1111/j.1600-079X.2004.00185.x"
- Description: Melatonin, a naturally occurring chemical mediator, although assigned a diverse range of functions, has attracted interest in recent years because of its ability to function as a free radical scavenger. Because of the implications of singlet oxygen in neurotoxicity, the objective of the study was to investigate the ability of melatonin to quench singlet oxygen generated using laser irradiation or lamp photolysis. The results show that melatonin produces radicals upon laser irradation while the lamp photolysis studies show that melatonin is able to scavenge singlet oxygen produced by naphthalene. While melatonin is a free radical scavenger under biological conditions, it acts as a generator of singlet oxygen and or radicals (as ΦΔ is 1.41) when irradiated with laser light, implying that it has the potential to be used in photodynamic therapy in the destruction of tumors.
- Full Text:
- Date Issued: 2005
- Authors: Maharaj, Deepa S , Molell, H , Antunes, Edith M , Maharaj, Hiren , Maree, D M , Nyokong, Tebello , Glass, Beverley D , Daya, Santy
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300335 , vital:57917 , xlink:href="https://doi.org/10.1111/j.1600-079X.2004.00185.x"
- Description: Melatonin, a naturally occurring chemical mediator, although assigned a diverse range of functions, has attracted interest in recent years because of its ability to function as a free radical scavenger. Because of the implications of singlet oxygen in neurotoxicity, the objective of the study was to investigate the ability of melatonin to quench singlet oxygen generated using laser irradiation or lamp photolysis. The results show that melatonin produces radicals upon laser irradation while the lamp photolysis studies show that melatonin is able to scavenge singlet oxygen produced by naphthalene. While melatonin is a free radical scavenger under biological conditions, it acts as a generator of singlet oxygen and or radicals (as ΦΔ is 1.41) when irradiated with laser light, implying that it has the potential to be used in photodynamic therapy in the destruction of tumors.
- Full Text:
- Date Issued: 2005
Methodological Decisions in Context: The dilemmas and challenges of novice African scholars
- Lupele, Justin, Mwingi, Mweru P, Kinyanjui, Felistus, Kimani, Joyce, Kisamba, Christine
- Authors: Lupele, Justin , Mwingi, Mweru P , Kinyanjui, Felistus , Kimani, Joyce , Kisamba, Christine
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373734 , vital:66717 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122698"
- Description: This paper emerges out of a panel discussion during a PhD week and subsequent 8th International Environmental Education Invitation Seminar held at Rhodes University in 2004 and 2005 respectively. It illuminates some insights into our struggles (as novice African researchers) in trying to respond to contextual realities as we research education and social change in African contexts, seeking insight into what counts as legitimate research in this context. The paper considers our struggles at conceptual, methodological, analytical and data generation levels, and in a politics of research. This is done by means of examples drawn from five current doctoral research projects being undertaken in east and southern African regions, using a review framework that represents fairly common dimensions of PhD research. We conclude that research, when defined rigidly within research disciplines/paradigms (as have been defined in some – primarily Western – research trajectories) may fail to take into account African social and contextual realities when applied uncritically. We argue that there is need for researchers in Africa to consider a multiplicity of approaches if research is to be meaningful in, and responsive to, social and contextual realities. In particular, we argue for taking account of socio historical and socio-cultural contexts in creating African epistemology in and through research.
- Full Text:
- Date Issued: 2005
- Authors: Lupele, Justin , Mwingi, Mweru P , Kinyanjui, Felistus , Kimani, Joyce , Kisamba, Christine
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373734 , vital:66717 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122698"
- Description: This paper emerges out of a panel discussion during a PhD week and subsequent 8th International Environmental Education Invitation Seminar held at Rhodes University in 2004 and 2005 respectively. It illuminates some insights into our struggles (as novice African researchers) in trying to respond to contextual realities as we research education and social change in African contexts, seeking insight into what counts as legitimate research in this context. The paper considers our struggles at conceptual, methodological, analytical and data generation levels, and in a politics of research. This is done by means of examples drawn from five current doctoral research projects being undertaken in east and southern African regions, using a review framework that represents fairly common dimensions of PhD research. We conclude that research, when defined rigidly within research disciplines/paradigms (as have been defined in some – primarily Western – research trajectories) may fail to take into account African social and contextual realities when applied uncritically. We argue that there is need for researchers in Africa to consider a multiplicity of approaches if research is to be meaningful in, and responsive to, social and contextual realities. In particular, we argue for taking account of socio historical and socio-cultural contexts in creating African epistemology in and through research.
- Full Text:
- Date Issued: 2005
Modelling the sustainable harvest of Sclerocarya birrea subsp. caffra fruits in the South African lowveld
- Emanuel, P L, Shackleton, Charlie M, Baxter, Jeremy
- Authors: Emanuel, P L , Shackleton, Charlie M , Baxter, Jeremy
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181312 , vital:43718 , xlink:href="https://doi.org/10.1016/j.foreco.2005.03.066"
- Description: Levels of commercialization, size class profile and fruit production of Sclerocarya birrea (marula) trees were studied in the Bushbuckridge region of South Africa. A stage-based population matrix model was used to estimate the sustainable yield for S. birrea fruit. The trees begin to bear fruit at an average size of 42.8 cm in circumference and this relates to an approximate age of 19 years. For a stable size class profile, the population growth rate, λ, was 1.1828758. The observed size class profile did not conform to the stable stage size class profile, obtained from the model. Thus, it was not possible to predict the state of the observed population. Using the model, it was estimated that 92% of fruit could be removed without impacting the current population profile. The management of other more destructive forms of S. birrea resource use (such as bark or firewood harvesting), however, do need to be monitored to limit negative impacts on the population that may reduce fruit availability for regeneration or cropping.
- Full Text:
- Date Issued: 2005
- Authors: Emanuel, P L , Shackleton, Charlie M , Baxter, Jeremy
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181312 , vital:43718 , xlink:href="https://doi.org/10.1016/j.foreco.2005.03.066"
- Description: Levels of commercialization, size class profile and fruit production of Sclerocarya birrea (marula) trees were studied in the Bushbuckridge region of South Africa. A stage-based population matrix model was used to estimate the sustainable yield for S. birrea fruit. The trees begin to bear fruit at an average size of 42.8 cm in circumference and this relates to an approximate age of 19 years. For a stable size class profile, the population growth rate, λ, was 1.1828758. The observed size class profile did not conform to the stable stage size class profile, obtained from the model. Thus, it was not possible to predict the state of the observed population. Using the model, it was estimated that 92% of fruit could be removed without impacting the current population profile. The management of other more destructive forms of S. birrea resource use (such as bark or firewood harvesting), however, do need to be monitored to limit negative impacts on the population that may reduce fruit availability for regeneration or cropping.
- Full Text:
- Date Issued: 2005
Monetary valuation of livelihoods for understanding the composition and complexity of rural households
- Dovie, Delali B K, Witkowski, Ed T F, Shackleton, Charlie M
- Authors: Dovie, Delali B K , Witkowski, Ed T F , Shackleton, Charlie M
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181346 , vital:43721 , xlink:href="https://doi.org/10.1007/s10460-004-7233-0"
- Description: There is, at present, little precise understanding of the relative contributions of the various income streams used by impoverished rural households in southern Africa. The impact of household profiles on overall income also is not well understood. There is, therefore, little consideration of these factors in national economic accounting. This paper is an attempt to reduce this gap in knowledge by reflecting on the relative contribution of agro-pastoralism, secondary woodland resources, and formal and informal cash income streams to households in the semi-arid rural village of Thorndale, Limpopo Province, South Africa. In the absence of jobs and confronted with high migrant labor, households with open access to natural resources derived more benefits from land-based livelihoods than cash income streams (i.e., 57.5 % vs. 42.5 %). Total livelihood income was valued at US$2887 per household per annum. A significant correlation between monetary values derived from crops and formal wages was established, and it was found that households with high cash incomes tended to invest more in crop production. Over 80 of households were male-headed. Of these heads of household, more than 60 were long-term migrants to urban areas, leaving household decision-making to the women. The low literacy rates of women have deprived them of paid jobs outside the area and, therefore, have increased their dependence on crops (62%) and secondary woodlands resources (60%). This was further reflected in the proportion of households in which females were the main contributors of cash income (9.7%), or joint contributors with men (24.4%). Various positive correlations were established between the number of women per household and the three land-based livelihoods. This implied that women’s total control over such activities was mostly a result of the absence of men and not a typical phenomenon. In spite of this control, it was not positively reflected in the lives of majority of the women. Households differed in their participation in livelihood activities. Household size influenced the level of production and was positively correlated with the value of secondary woodland resources and crops. The study shows the interdependence of land-based livelihood sources and the impact of household features on production and consumption. Policies that focus on livelihood options need to recognize and accommodate associated household dynamics.
- Full Text:
- Date Issued: 2005
- Authors: Dovie, Delali B K , Witkowski, Ed T F , Shackleton, Charlie M
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181346 , vital:43721 , xlink:href="https://doi.org/10.1007/s10460-004-7233-0"
- Description: There is, at present, little precise understanding of the relative contributions of the various income streams used by impoverished rural households in southern Africa. The impact of household profiles on overall income also is not well understood. There is, therefore, little consideration of these factors in national economic accounting. This paper is an attempt to reduce this gap in knowledge by reflecting on the relative contribution of agro-pastoralism, secondary woodland resources, and formal and informal cash income streams to households in the semi-arid rural village of Thorndale, Limpopo Province, South Africa. In the absence of jobs and confronted with high migrant labor, households with open access to natural resources derived more benefits from land-based livelihoods than cash income streams (i.e., 57.5 % vs. 42.5 %). Total livelihood income was valued at US$2887 per household per annum. A significant correlation between monetary values derived from crops and formal wages was established, and it was found that households with high cash incomes tended to invest more in crop production. Over 80 of households were male-headed. Of these heads of household, more than 60 were long-term migrants to urban areas, leaving household decision-making to the women. The low literacy rates of women have deprived them of paid jobs outside the area and, therefore, have increased their dependence on crops (62%) and secondary woodlands resources (60%). This was further reflected in the proportion of households in which females were the main contributors of cash income (9.7%), or joint contributors with men (24.4%). Various positive correlations were established between the number of women per household and the three land-based livelihoods. This implied that women’s total control over such activities was mostly a result of the absence of men and not a typical phenomenon. In spite of this control, it was not positively reflected in the lives of majority of the women. Households differed in their participation in livelihood activities. Household size influenced the level of production and was positively correlated with the value of secondary woodland resources and crops. The study shows the interdependence of land-based livelihood sources and the impact of household features on production and consumption. Policies that focus on livelihood options need to recognize and accommodate associated household dynamics.
- Full Text:
- Date Issued: 2005
Multivariate analysis of honeybees, Apis mellifera Linnaeus (Hymenoptera: Apidae) of the northeastern and southern regions of Algeria.
- Barour, C, Tahar, A, Radloff, Sarah E, Hepburn, H Randall
- Authors: Barour, C , Tahar, A , Radloff, Sarah E , Hepburn, H Randall
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451976 , vital:75092 , https://hdl.handle.net/10520/EJC32628
- Description: Morphometric characters of worker honeybees, Apis mellifera Linnaeus, were analysed by multivariate methods to characterize their populations in the northeastern and southern regions (ecological-climatological zones) of Algeria, from 36°55' to 32°25'N and 3°39' to 8°22'E. Three morphoclusters were identified by using principal components and linear discriminant analyses. The bees are identified as Apis mellifera intermissa Buttel-Reepen.
- Full Text:
- Date Issued: 2005
- Authors: Barour, C , Tahar, A , Radloff, Sarah E , Hepburn, H Randall
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451976 , vital:75092 , https://hdl.handle.net/10520/EJC32628
- Description: Morphometric characters of worker honeybees, Apis mellifera Linnaeus, were analysed by multivariate methods to characterize their populations in the northeastern and southern regions (ecological-climatological zones) of Algeria, from 36°55' to 32°25'N and 3°39' to 8°22'E. Three morphoclusters were identified by using principal components and linear discriminant analyses. The bees are identified as Apis mellifera intermissa Buttel-Reepen.
- Full Text:
- Date Issued: 2005
NUMSA Bulletin - Two enonomies, a global problem?
- NUMSA
- Authors: NUMSA
- Date: Sep 2005
- Subjects: NUMSA
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/114043 , vital:33882
- Description: It is a year since the last Numsa Bulletin was published in September 2004. Last year Numsa's educators forum discussed how we could use the Numsa Bulletin more effectively. Included in this Bulletin are a number of topical issues that challenge you to debate issues at your local shop steward councils or your workplaces: If you are violently opposed to GEAR, have your views challenged by Motlanthe (page 14), Get your local to analyse what was agreed in the Alliance Summit earlier this year and give your score on whether you think the Alliance has met its targets (pages 22-23). Debate differences between the ANC's NGC document on two economies and Cosatu's response (pages 24-27). If you are an engineering shop steward in Middelburg, Witbank, Vanderbijlpark, Richards Bay, Pietermaritzburg, Vereeniging, then force a debate on the slow integration of House Agreements into the Main Agreement (pages 40-41). If you are an auto shop steward, then read Dumisa Ntuli's ideas (pages 42-44) on the shortcomings with black economic empowerment initiatives in the auto industry and debate the issues in your local/workplace. When was the last time you briefed members in your workplace? Do the organisational test on page 49 and see if you are up to the job. If you fail, redeem yourself by reading the health and safety, training and education sections and then debating and discussing the contents with your fellow members.
- Full Text:
- Date Issued: Sep 2005
- Authors: NUMSA
- Date: Sep 2005
- Subjects: NUMSA
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/114043 , vital:33882
- Description: It is a year since the last Numsa Bulletin was published in September 2004. Last year Numsa's educators forum discussed how we could use the Numsa Bulletin more effectively. Included in this Bulletin are a number of topical issues that challenge you to debate issues at your local shop steward councils or your workplaces: If you are violently opposed to GEAR, have your views challenged by Motlanthe (page 14), Get your local to analyse what was agreed in the Alliance Summit earlier this year and give your score on whether you think the Alliance has met its targets (pages 22-23). Debate differences between the ANC's NGC document on two economies and Cosatu's response (pages 24-27). If you are an engineering shop steward in Middelburg, Witbank, Vanderbijlpark, Richards Bay, Pietermaritzburg, Vereeniging, then force a debate on the slow integration of House Agreements into the Main Agreement (pages 40-41). If you are an auto shop steward, then read Dumisa Ntuli's ideas (pages 42-44) on the shortcomings with black economic empowerment initiatives in the auto industry and debate the issues in your local/workplace. When was the last time you briefed members in your workplace? Do the organisational test on page 49 and see if you are up to the job. If you fail, redeem yourself by reading the health and safety, training and education sections and then debating and discussing the contents with your fellow members.
- Full Text:
- Date Issued: Sep 2005
Photochemical and photophysical properties of pentoxy-and naphthaloxy appended magnesium and zinc phthalocyanines
- Maqanda, Wesiwe, Nyokong, Tebello, Maree, David M
- Authors: Maqanda, Wesiwe , Nyokong, Tebello , Maree, David M
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289260 , vital:56613 , xlink:href="https://doi.org/10.1142/S1088424605000435"
- Description: Photochemical and photophysical measurements were conducted on pentoxy and naphthaloxy appended zinc and magnesium phthalocyanines. We describe in this paper the synthesis as well as unexpected photodegradation behavior of naphthaloxy appended magnesium phthalocyanines. General trends are described for quantum yields of photodegradation, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds.
- Full Text:
- Date Issued: 2005
- Authors: Maqanda, Wesiwe , Nyokong, Tebello , Maree, David M
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289260 , vital:56613 , xlink:href="https://doi.org/10.1142/S1088424605000435"
- Description: Photochemical and photophysical measurements were conducted on pentoxy and naphthaloxy appended zinc and magnesium phthalocyanines. We describe in this paper the synthesis as well as unexpected photodegradation behavior of naphthaloxy appended magnesium phthalocyanines. General trends are described for quantum yields of photodegradation, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds.
- Full Text:
- Date Issued: 2005