Atterrissage
- TP Audiorama Orchestra (performers), Showbiz
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129611 , vital:36313 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-08
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129611 , vital:36313 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-08
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
Paris 95
- TP Audiorama Orchestra (performers), Showbiz
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129596 , vital:36310 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-05
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129596 , vital:36310 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-05
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
Wui
- TP Audiorama Orchestra (performers), Showbiz
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129601 , vital:36311 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-06
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129601 , vital:36311 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-06
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
Mariage
- TP Audiorama Orchestra (performers), Showbiz
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129569 , vital:36307 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-02
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129569 , vital:36307 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-02
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
A Pi Cheche
- TP Audiorama Orchestra (performers), Showbiz
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129578 , vital:36308 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-03
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129578 , vital:36308 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-03
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
Ahoussa Kabun
- TP Audiorama Orchestra (performers), Showbiz
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129583 , vital:36309 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-04
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129583 , vital:36309 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-04
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
Assi Olivier
- TP Audiorama Orchestra (performers), Showbiz
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129606 , vital:36312 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-07
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
- Authors: TP Audiorama Orchestra (performers) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129606 , vital:36312 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-07
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
Retour a la Terre
- N'Gbocho Anoma Jacques (vocals), Kokora Bongoua (written, composed, arranged by), Robert (alto saxophone), Oumar Maxim, Narcisse (bass guitar), Yapo Jimmy, Kilola De Bela Bela (chorus), Tia Pierre (Congas Toumba), Aye Hilarion (guitar), Bongoua Joachim (solo guitar, leader), Aka Yapi Mathieu, Diby Atse Edmond, Anoma Jacques, Seka Rosa (lead vocals), Osei Kwame (organ, synthesizer), Mario Zani (tenor saxophone), Georges, Isaac, Akissi Leion (trumbet), Showbiz
- Authors: N'Gbocho Anoma Jacques (vocals) , Kokora Bongoua (written, composed, arranged by) , Robert (alto saxophone) , Oumar Maxim, Narcisse (bass guitar) , Yapo Jimmy, Kilola De Bela Bela (chorus) , Tia Pierre (Congas Toumba) , Aye Hilarion (guitar) , Bongoua Joachim (solo guitar, leader) , Aka Yapi Mathieu, Diby Atse Edmond, Anoma Jacques, Seka Rosa (lead vocals) , Osei Kwame (organ, synthesizer) , Mario Zani (tenor saxophone) , Georges, Isaac, Akissi Leion (trumbet) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129560 , vital:36306 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-01
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
- Authors: N'Gbocho Anoma Jacques (vocals) , Kokora Bongoua (written, composed, arranged by) , Robert (alto saxophone) , Oumar Maxim, Narcisse (bass guitar) , Yapo Jimmy, Kilola De Bela Bela (chorus) , Tia Pierre (Congas Toumba) , Aye Hilarion (guitar) , Bongoua Joachim (solo guitar, leader) , Aka Yapi Mathieu, Diby Atse Edmond, Anoma Jacques, Seka Rosa (lead vocals) , Osei Kwame (organ, synthesizer) , Mario Zani (tenor saxophone) , Georges, Isaac, Akissi Leion (trumbet) , Showbiz
- Date: 1998
- Subjects: Popular music , Popular music--Africa, West , Africa Cote d'Ivoire Abidjan f-iv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129560 , vital:36306 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC30-01
- Description: Ako music from Cote d'Ivoire performed by the TP Audiorama Orchestra, the first orchestra to develp this genre of Ivorian music
- Full Text: false
- Date Issued: 1998
Asymmetric induction in reactions of chiral carboxylic esters and silyl enol ethers
- Authors: Evans, Melanie Daryl
- Date: 1998
- Subjects: Ethers -- Synthesis Esters -- Synthesis Chirality Asymmetric synthesis Organic compounds -- Synthesis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4409 , http://hdl.handle.net/10962/d1006762
- Description: Several camphor and pinane derivatives have been synthesised and evaluated for use as chiral auxiliaries in asymmetric synthesis. Various blocking groups have been attached to the camphor skeleton in attempts to improve stereofacial selectivity; these include α-methoxybenzyl and xylyl groups, and novel stereoisomeric ketal moieties derived from meso- and (R,R)-(-)-2,3-butanediol. Benzylation reactions carried out on the lithium enolates of ester derivatives of the camphor-derived chiral auxiliaries afforded α-benzylated products in 5-60% diastereomeric excess. Stereochemical aspects have been explored using high resolution NMR, X-ray crystallographic and computer modelling techniques, and hydrolysis of selected α-benzylated products has permitted the diasteroselective bias to be confirmed. Opposite configurations at the new stereogenic centre are clearly favoured by the xylyl and ketal blocking groups - an observation rationalised in terms of the presence or absence of chelating potential in the blocking group. Baylis-Hillman reactions carried out on a series of specially prepared camphor-derived acrylic esters containing the ketal blocking group exhibited both low diastereoselectivities (0-30% d.e.) and very long reaction times. Chiral silyl enol ethers, synthesised using both pinane and camphor derivatives as chiral auxiliaries, showed up to 20% diastereomeric excess in MCPBA oxidation, alkylation and Mukaiyama reactions. Attempts to bring the prochiral centre in the silyl enol ether substrates closer to the chiral auxiliary, and thus improve the stereofacial selectivity, proved unsuccessful. The silyl enol ether derivatives, however, display interesting fragmentation patterns in their electron impact mass spectra, which were investigated using a combination of high resolution MS, comparative low resolution MS and metastable peak analysis.
- Full Text:
- Date Issued: 1998
- Authors: Evans, Melanie Daryl
- Date: 1998
- Subjects: Ethers -- Synthesis Esters -- Synthesis Chirality Asymmetric synthesis Organic compounds -- Synthesis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4409 , http://hdl.handle.net/10962/d1006762
- Description: Several camphor and pinane derivatives have been synthesised and evaluated for use as chiral auxiliaries in asymmetric synthesis. Various blocking groups have been attached to the camphor skeleton in attempts to improve stereofacial selectivity; these include α-methoxybenzyl and xylyl groups, and novel stereoisomeric ketal moieties derived from meso- and (R,R)-(-)-2,3-butanediol. Benzylation reactions carried out on the lithium enolates of ester derivatives of the camphor-derived chiral auxiliaries afforded α-benzylated products in 5-60% diastereomeric excess. Stereochemical aspects have been explored using high resolution NMR, X-ray crystallographic and computer modelling techniques, and hydrolysis of selected α-benzylated products has permitted the diasteroselective bias to be confirmed. Opposite configurations at the new stereogenic centre are clearly favoured by the xylyl and ketal blocking groups - an observation rationalised in terms of the presence or absence of chelating potential in the blocking group. Baylis-Hillman reactions carried out on a series of specially prepared camphor-derived acrylic esters containing the ketal blocking group exhibited both low diastereoselectivities (0-30% d.e.) and very long reaction times. Chiral silyl enol ethers, synthesised using both pinane and camphor derivatives as chiral auxiliaries, showed up to 20% diastereomeric excess in MCPBA oxidation, alkylation and Mukaiyama reactions. Attempts to bring the prochiral centre in the silyl enol ether substrates closer to the chiral auxiliary, and thus improve the stereofacial selectivity, proved unsuccessful. The silyl enol ether derivatives, however, display interesting fragmentation patterns in their electron impact mass spectra, which were investigated using a combination of high resolution MS, comparative low resolution MS and metastable peak analysis.
- Full Text:
- Date Issued: 1998
Ammophila arenaria (L.) Link (marram grass) in South Africa and its potential invasiveness
- Authors: Hertling, Ursula Margret
- Date: 1998
- Subjects: Grasses -- South Africa Alien plants -- South Africa Sand dune plants -- South Africa Grasses -- Ecology -- South Africa Sand dune ecology -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4198 , http://hdl.handle.net/10962/d1003767
- Description: Ammophila arenaria (L.) Link is a European sand binding plant which was introduced to South Africa in the 1870's for the purpose of dune stabilisation. Because of its known invasiveness along the west coast of North America, and the problems South African ecosystems experience with alien invader plants, it was deemed necessary to study the biology and ecology of this species in South Africa. The aim of this thesis is to establish the potential invasiveness of A. arenaria on Cape coastal dunes and assess whether its use for dune stabilisation is still justifiable. A. arenaria occurs nowadays between the Langebaan area on the west coast and Gonubie in the Eastern Cape. Although widespread, the grass appears to occur only in areas where it has been planted. Its unaided spread may be prevented by adverse climatic conditions. Studies on the community biology of South African A. arenaria communities as compared to indigenous dune plant communities and natural A. arenaria communities in Europe cannot confirm the aggressive behaviour that A. arenaria shows in California and Oregon. In South Africa, A. arenaria does not exert strong floristic control over other species or outcompete and replace them, neither does it alter the topography of South African beaches and dunes. It forms weaker species associations and tends to develop communities of little species variability along the coast, thereby proving its alienness in South Africa, but this does not imply its invasiveness. Studies on succession of A. arenaria stabilisation areas show that monospecific A. arenaria plantings can be succeeded by a species-rich indigenous dune scrub or dune fynbos within a few decades. Plant-parasitic nematodes have been recorded, which may play an important role in the succession of A. arenaria stands in South Africa as was observed in Europe. Monitoring of A. arenaria communities and indigenous communities over nearly three years shows that A. arenaria is not spreading and replacing indigenous plants but in fact rather being replaced by the latter. A. arenaria profits from a superior sand burial tolerance but is affected by adverse climatic factors, mostly the lack of rainfall and strong radiation. In comparison to the indigenous dune grasses Thinopyrum distichum and Ehrharta villosa, it does not show any superior demographic traits such as an unusually high growth rate or large aboveground biomass production. Although A. arenaria produces viable seed in South Africa, the indigenous grasses show better germination and seedling establishment in the field. This study indicates that A. arenaria is not invasive in South Africa, nor likely to become an invader species in the near future. However, more research is required to confirm these results and more caution recommended regarding the further use of this alien grass for dune stabilisation.
- Full Text:
- Date Issued: 1998
- Authors: Hertling, Ursula Margret
- Date: 1998
- Subjects: Grasses -- South Africa Alien plants -- South Africa Sand dune plants -- South Africa Grasses -- Ecology -- South Africa Sand dune ecology -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4198 , http://hdl.handle.net/10962/d1003767
- Description: Ammophila arenaria (L.) Link is a European sand binding plant which was introduced to South Africa in the 1870's for the purpose of dune stabilisation. Because of its known invasiveness along the west coast of North America, and the problems South African ecosystems experience with alien invader plants, it was deemed necessary to study the biology and ecology of this species in South Africa. The aim of this thesis is to establish the potential invasiveness of A. arenaria on Cape coastal dunes and assess whether its use for dune stabilisation is still justifiable. A. arenaria occurs nowadays between the Langebaan area on the west coast and Gonubie in the Eastern Cape. Although widespread, the grass appears to occur only in areas where it has been planted. Its unaided spread may be prevented by adverse climatic conditions. Studies on the community biology of South African A. arenaria communities as compared to indigenous dune plant communities and natural A. arenaria communities in Europe cannot confirm the aggressive behaviour that A. arenaria shows in California and Oregon. In South Africa, A. arenaria does not exert strong floristic control over other species or outcompete and replace them, neither does it alter the topography of South African beaches and dunes. It forms weaker species associations and tends to develop communities of little species variability along the coast, thereby proving its alienness in South Africa, but this does not imply its invasiveness. Studies on succession of A. arenaria stabilisation areas show that monospecific A. arenaria plantings can be succeeded by a species-rich indigenous dune scrub or dune fynbos within a few decades. Plant-parasitic nematodes have been recorded, which may play an important role in the succession of A. arenaria stands in South Africa as was observed in Europe. Monitoring of A. arenaria communities and indigenous communities over nearly three years shows that A. arenaria is not spreading and replacing indigenous plants but in fact rather being replaced by the latter. A. arenaria profits from a superior sand burial tolerance but is affected by adverse climatic factors, mostly the lack of rainfall and strong radiation. In comparison to the indigenous dune grasses Thinopyrum distichum and Ehrharta villosa, it does not show any superior demographic traits such as an unusually high growth rate or large aboveground biomass production. Although A. arenaria produces viable seed in South Africa, the indigenous grasses show better germination and seedling establishment in the field. This study indicates that A. arenaria is not invasive in South Africa, nor likely to become an invader species in the near future. However, more research is required to confirm these results and more caution recommended regarding the further use of this alien grass for dune stabilisation.
- Full Text:
- Date Issued: 1998
Profile on POTWA
- Post and Telecommunications Workers Association (Potwa)
- Authors: Post and Telecommunications Workers Association (Potwa)
- Date: 1998
- Subjects: POTWA
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/250717 , vital:52042
- Description: POTWA was formed in August 1986 in Soweto after workers’ rejection of the liaison committees and workers’ councils tailored by management for black workers in the Department of Post and Telecommunications. Racist salaries also helped to mobilise workers into the union. At the launching congress, Potwa had already signed-up 10 000 members year, the union settled wage claims in nine regions.
- Full Text:
- Date Issued: 1998
- Authors: Post and Telecommunications Workers Association (Potwa)
- Date: 1998
- Subjects: POTWA
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/250717 , vital:52042
- Description: POTWA was formed in August 1986 in Soweto after workers’ rejection of the liaison committees and workers’ councils tailored by management for black workers in the Department of Post and Telecommunications. Racist salaries also helped to mobilise workers into the union. At the launching congress, Potwa had already signed-up 10 000 members year, the union settled wage claims in nine regions.
- Full Text:
- Date Issued: 1998
Morphological and genetic differentiation of Patella granularis (Gastropoda: Patellidae): recognition of two sibling species along the coast of southern Africa
- Ridgway, Tyronne M, Stewart, Barbara A, Branch, George M, Hodgson, Alan N
- Authors: Ridgway, Tyronne M , Stewart, Barbara A , Branch, George M , Hodgson, Alan N
- Date: 1998
- Subjects: Patellidae
- Language: English
- Type: Article
- Identifier: vital:6944 , http://hdl.handle.net/10962/d1011971
- Description: Morphological and isozyme variations between 13 populations of the species hitherto named Patella granularis were investigated to see whether differences in shell structure between the west coast versus the south and east coasts of southern Africa are supported by other morphological features or by genetic differences. The shells showed a definite decrease in size from west to east, but this is correlated with productivity and is of no diagnostic use in distinguishing between populations. Discriminant functions analysis based on shell morphometrics failed to separate populations from the three coastal regions. Shells from the northern east coast do, however, have shell nodules with a dark pigmentation, distinctly separating them from those further south and west. No differences in radular or soft part morphology were detected between the populations, but the four northernmost populations on the east coast have a significantly shorter Z looping of the gut than the other populations along the coast. Significant microstructural differences in the sperm were also detected between these two groups of populations. Electrophoretic analysis of 16 enzyme loci failed to detect any significant differences between the west and south coast populations, but revealed a genetic identity (Nei) of 0.528 as well as four diagnostic alleles between the four northernmost populations from the east coast compared with those to the south and west. The two genetically distinct forms occurred sympatrically at one of the study sites on the east coast (Coffee Bay). It was concluded the two groupings were sufficiently different to warrant the recognition of a separate species, which is centred in KwaZulu-Natal on the east coast and extends south to Coffee Bay, from where it is replaced by P. granularis. There is, however, no evidence at all that the west coast populations are in any way separable from the remaining populations of P. granularis on the south coast.
- Full Text:
- Date Issued: 1998
- Authors: Ridgway, Tyronne M , Stewart, Barbara A , Branch, George M , Hodgson, Alan N
- Date: 1998
- Subjects: Patellidae
- Language: English
- Type: Article
- Identifier: vital:6944 , http://hdl.handle.net/10962/d1011971
- Description: Morphological and isozyme variations between 13 populations of the species hitherto named Patella granularis were investigated to see whether differences in shell structure between the west coast versus the south and east coasts of southern Africa are supported by other morphological features or by genetic differences. The shells showed a definite decrease in size from west to east, but this is correlated with productivity and is of no diagnostic use in distinguishing between populations. Discriminant functions analysis based on shell morphometrics failed to separate populations from the three coastal regions. Shells from the northern east coast do, however, have shell nodules with a dark pigmentation, distinctly separating them from those further south and west. No differences in radular or soft part morphology were detected between the populations, but the four northernmost populations on the east coast have a significantly shorter Z looping of the gut than the other populations along the coast. Significant microstructural differences in the sperm were also detected between these two groups of populations. Electrophoretic analysis of 16 enzyme loci failed to detect any significant differences between the west and south coast populations, but revealed a genetic identity (Nei) of 0.528 as well as four diagnostic alleles between the four northernmost populations from the east coast compared with those to the south and west. The two genetically distinct forms occurred sympatrically at one of the study sites on the east coast (Coffee Bay). It was concluded the two groupings were sufficiently different to warrant the recognition of a separate species, which is centred in KwaZulu-Natal on the east coast and extends south to Coffee Bay, from where it is replaced by P. granularis. There is, however, no evidence at all that the west coast populations are in any way separable from the remaining populations of P. granularis on the south coast.
- Full Text:
- Date Issued: 1998
The theoretical and empirical analysis of trade integration among unequal partners : implications for the Southern African Development Community
- Authors: Cattaneo, Nicolette Sylvie
- Date: 1998
- Subjects: Southern African Development Community , Customs unions , Africa, Southern -- Foreign economic relations , Africa, Southern -- Economic integration
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1008 , http://hdl.handle.net/10962/d1002743 , Southern African Development Community , Customs unions , Africa, Southern -- Foreign economic relations , Africa, Southern -- Economic integration
- Description: The re-acceptance of South Africa into the international community has cleared the path for the closer integration of South Africa with its neighbours in a broader southern African regional union. In particular, the countries of the Southern African Development Community {SADC), which South Africa joined in August 1994, have committed themselves to the formation of a free trade area (FTA) over an eight-year period. The most likely impediment to this process is the perception of a highly unequal distribution of the economic gains and losses of such an arrangement. This reflects the particular context of SADC: one of a comparatively undeveloped region, dominated by a relatively large, more industrially advanced country, which is itself small by international standards. The essential question with which this study is concerned, therefore, is whether, despite the existing inequalities in the region, a FTA among SADC members could be mutually beneficial to South Africa and its partners. The thesis applies orthodox and new trade theory to the analysis of economic integration among unequal partners. Using the theoretical analysis, and with reference to empirical studies of such experience elsewhere in the world, it attempts to provide an assessment of the existing body of literature on the possible effects of a SADC FTA. In the light of this discussion, and from its own preliminary empirical analysis of the possible pattern of inter-sectoral versus intra-sectoral specialisation which may result on union, the study suggests ways in which a fuller evaluation of the welfare implications of a southern African FTA may be achieved. The thesis argues that the orthodox theory based on perfect competition provides an insufficient framework for the analysis of the likely effects of a SADC FT A. It finds that, firstly, in an alternative analytical framework which retains the assumption of perfect competition, there may be other criteria for judging the success of a regional union that are neglected by orthodoxy, particularly in the case of developing countries. Secondly, the new trade theory based on imperfect competition and product differentiation provides useful insights into the possible effects of a regional union among countries at unequal levels of development. The formal extension of this body of literature to the theory of economic integration is clearly called for. It is found, however, that neither orthodox customs union theory, nor its suggested alternatives and extensions, enable one to conclude, a priori, that the formation of a FTA in the southern African region could not be beneficial to both South Africa and its smaller partners. Further, the present empirical studies on SADC do not take account of the full range of factors necessary for a complete welfare assessment of the possible effects. Since the outcome of integration depends on the empirical circumstances of the particular case, and since the information necessary for a comprehensive welfare evaluation is not currently available, the study concludes that the countries of the region have committed themselves to a FTA without any definite knowledge of its likely effects.
- Full Text:
- Date Issued: 1998
- Authors: Cattaneo, Nicolette Sylvie
- Date: 1998
- Subjects: Southern African Development Community , Customs unions , Africa, Southern -- Foreign economic relations , Africa, Southern -- Economic integration
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1008 , http://hdl.handle.net/10962/d1002743 , Southern African Development Community , Customs unions , Africa, Southern -- Foreign economic relations , Africa, Southern -- Economic integration
- Description: The re-acceptance of South Africa into the international community has cleared the path for the closer integration of South Africa with its neighbours in a broader southern African regional union. In particular, the countries of the Southern African Development Community {SADC), which South Africa joined in August 1994, have committed themselves to the formation of a free trade area (FTA) over an eight-year period. The most likely impediment to this process is the perception of a highly unequal distribution of the economic gains and losses of such an arrangement. This reflects the particular context of SADC: one of a comparatively undeveloped region, dominated by a relatively large, more industrially advanced country, which is itself small by international standards. The essential question with which this study is concerned, therefore, is whether, despite the existing inequalities in the region, a FTA among SADC members could be mutually beneficial to South Africa and its partners. The thesis applies orthodox and new trade theory to the analysis of economic integration among unequal partners. Using the theoretical analysis, and with reference to empirical studies of such experience elsewhere in the world, it attempts to provide an assessment of the existing body of literature on the possible effects of a SADC FTA. In the light of this discussion, and from its own preliminary empirical analysis of the possible pattern of inter-sectoral versus intra-sectoral specialisation which may result on union, the study suggests ways in which a fuller evaluation of the welfare implications of a southern African FTA may be achieved. The thesis argues that the orthodox theory based on perfect competition provides an insufficient framework for the analysis of the likely effects of a SADC FT A. It finds that, firstly, in an alternative analytical framework which retains the assumption of perfect competition, there may be other criteria for judging the success of a regional union that are neglected by orthodoxy, particularly in the case of developing countries. Secondly, the new trade theory based on imperfect competition and product differentiation provides useful insights into the possible effects of a regional union among countries at unequal levels of development. The formal extension of this body of literature to the theory of economic integration is clearly called for. It is found, however, that neither orthodox customs union theory, nor its suggested alternatives and extensions, enable one to conclude, a priori, that the formation of a FTA in the southern African region could not be beneficial to both South Africa and its smaller partners. Further, the present empirical studies on SADC do not take account of the full range of factors necessary for a complete welfare assessment of the possible effects. Since the outcome of integration depends on the empirical circumstances of the particular case, and since the information necessary for a comprehensive welfare evaluation is not currently available, the study concludes that the countries of the region have committed themselves to a FTA without any definite knowledge of its likely effects.
- Full Text:
- Date Issued: 1998
Baylis-Hillman derived benzopyrans and related systems : a synthetic and mechanistic study
- Authors: Robinson, Ross Stuart
- Date: 1998
- Subjects: Benzopyrans Coumarins Heterocyclic compounds -- Derivatives
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4429 , http://hdl.handle.net/10962/d1007193
- Description: The Baylis-Hillman reaction between substituted salicylaldehydes and various acrylate species has been shown to afford complex reaction mixtures, careful chromatography of which has led to the isolation of an extensive range of novel compounds. One- and two-dimensional NMR spectroscopic, mass spectrometric and X-ray crystallographic analysis of these compounds have permitted identification of no less than eight general classes of chromene and coumarin derivatives. The formation of the various product types is attributed to cascades of successive reactions stemming, in each case, from a Baylis-Hillman product as the common intermediate. The mechanistic sequence involved in the formation of the various chromene and coumarin derivatives have been elucidated by examining isolated or specifically prepared compounds as putative reaction intermediates. Conjugate addition and acyl or allylic substitution by various nucleophiles appear to be common processes in the formation of the chromene and coumarin derivatives, and studies focussing on these processes have been undertaken. Reactions of Baylis-Hillman adducts have been carried out, using oxygen, sulfur and nitrogen nucleophiles, in order to explore stereoselectivity and regioselectivity trends. The results show that the reactions proceed with a very high degree of regioselectivity, affording conjugate addition rather than acyl substitution products. The diastereoselectivity observed for the addition products, however was typically low. A kinetic study to explore the regioselectivity of the reaction between various Baylis-Hillman derived halogeno esters and the nucleophile, methyl 3-oxobutanolate enloate, in two different base-solvent systems at high dilution was also undertaken. The reactions were monitored by ¹H NMR spectroscopy, and the results revealed that the reaction kinetics are more complex than originally anticipated. A mechanistic rationalisation is offered which is consistent with both the kinetic data and the observed regioselectivity trends.
- Full Text:
- Date Issued: 1998
- Authors: Robinson, Ross Stuart
- Date: 1998
- Subjects: Benzopyrans Coumarins Heterocyclic compounds -- Derivatives
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4429 , http://hdl.handle.net/10962/d1007193
- Description: The Baylis-Hillman reaction between substituted salicylaldehydes and various acrylate species has been shown to afford complex reaction mixtures, careful chromatography of which has led to the isolation of an extensive range of novel compounds. One- and two-dimensional NMR spectroscopic, mass spectrometric and X-ray crystallographic analysis of these compounds have permitted identification of no less than eight general classes of chromene and coumarin derivatives. The formation of the various product types is attributed to cascades of successive reactions stemming, in each case, from a Baylis-Hillman product as the common intermediate. The mechanistic sequence involved in the formation of the various chromene and coumarin derivatives have been elucidated by examining isolated or specifically prepared compounds as putative reaction intermediates. Conjugate addition and acyl or allylic substitution by various nucleophiles appear to be common processes in the formation of the chromene and coumarin derivatives, and studies focussing on these processes have been undertaken. Reactions of Baylis-Hillman adducts have been carried out, using oxygen, sulfur and nitrogen nucleophiles, in order to explore stereoselectivity and regioselectivity trends. The results show that the reactions proceed with a very high degree of regioselectivity, affording conjugate addition rather than acyl substitution products. The diastereoselectivity observed for the addition products, however was typically low. A kinetic study to explore the regioselectivity of the reaction between various Baylis-Hillman derived halogeno esters and the nucleophile, methyl 3-oxobutanolate enloate, in two different base-solvent systems at high dilution was also undertaken. The reactions were monitored by ¹H NMR spectroscopy, and the results revealed that the reaction kinetics are more complex than originally anticipated. A mechanistic rationalisation is offered which is consistent with both the kinetic data and the observed regioselectivity trends.
- Full Text:
- Date Issued: 1998
A new luminous cardinalfish of the genus Apogon (Perciformes:Apogonidae) from the western Pacific Ocean
- Gon, O (Ofer), 1949-, Allen, Gerald R, J.L.B. Smith Institute of Ichthyology
- Authors: Gon, O (Ofer), 1949- , Allen, Gerald R , J.L.B. Smith Institute of Ichthyology
- Date: 1998-11
- Subjects: Apogon -- Pacific Ocean -- Classification , Apogon -- Pacific Ocean -- Identification , Bioluminescence -- Pacific Ocean
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/71022 , vital:29770 , Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB)) Periodicals Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB))
- Description: Online version of original print edition of the Special Publication of the J.L.B. Smith Institute of Ichthyology; No. 62 , A new species of cardinalfish, Apogon photogaster is described based on 11 specimens from Madang Lagoon in Papua New Guinea and Galoc Island in the Philippines. This new species has 15 pectoral rays, 2 predorsal scales, 15-18 gill-rakers (8-9 developed), and 7 gill-rakers on the ceratobranchial o f the first gill-arch. It has a unique bioluminescent system, including a light organ branching forward from the second loop of the intestine and a diffuser organ along the ventrolateral part of the body.
- Full Text:
- Date Issued: 1998-11
- Authors: Gon, O (Ofer), 1949- , Allen, Gerald R , J.L.B. Smith Institute of Ichthyology
- Date: 1998-11
- Subjects: Apogon -- Pacific Ocean -- Classification , Apogon -- Pacific Ocean -- Identification , Bioluminescence -- Pacific Ocean
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/71022 , vital:29770 , Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB)) Periodicals Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB))
- Description: Online version of original print edition of the Special Publication of the J.L.B. Smith Institute of Ichthyology; No. 62 , A new species of cardinalfish, Apogon photogaster is described based on 11 specimens from Madang Lagoon in Papua New Guinea and Galoc Island in the Philippines. This new species has 15 pectoral rays, 2 predorsal scales, 15-18 gill-rakers (8-9 developed), and 7 gill-rakers on the ceratobranchial o f the first gill-arch. It has a unique bioluminescent system, including a light organ branching forward from the second loop of the intestine and a diffuser organ along the ventrolateral part of the body.
- Full Text:
- Date Issued: 1998-11
Vulnerability, irreplaceability and reserve selection for the elephant-impacted flora of the Addo National Elephant Park, Eastern Cape, South Africa
- Authors: Johnson, Catherine Fiona
- Date: 1998
- Subjects: Addo Elephant National Park (South Africa) , Veld plants -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4202 , http://hdl.handle.net/10962/d1003771 , Addo Elephant National Park (South Africa) , Veld plants -- South Africa -- Eastern Cape
- Description: The Addo Elephant National Park (AENP) is the only existing national park situated in succulent thicket. This unique veld type is endemic to the Eastern Cape, and forms an important centre of endemism for small succulents and geophytes which comprise the subdominant component of the vegetation. It is regarded as the most threatened vegetation type in the Eastern Cape, as much of it has been severely degraded by farming activities and its rate of regeneration is very low. Thus the AENP represents an important sanctuary for certain species. However, large herbivores, particularly elephants, pose a further threat to the vegetation, and areas from which elephants have been excluded in the park (botanical reserves) have been shown to be more speciesrich than the surrounding vegetation. Most elephant-impact studies have focussed on the large shrub component of the vegetation, and only preliminary studies have been done in AENP to date. As the elephant population continues to grow, there is pressure to utilise the botanical reserves to increase the amount of available grazing. It is thus important that the botanical reserve system be highly effective and efficient in terms of area. Existing botanical reserves were established ad hoc and are therefore not necessarily optimal in this regard. An iterative reserve-selection algorithm was used to maximise plant species conservation in the most efficient area.
- Full Text:
- Date Issued: 1998
- Authors: Johnson, Catherine Fiona
- Date: 1998
- Subjects: Addo Elephant National Park (South Africa) , Veld plants -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4202 , http://hdl.handle.net/10962/d1003771 , Addo Elephant National Park (South Africa) , Veld plants -- South Africa -- Eastern Cape
- Description: The Addo Elephant National Park (AENP) is the only existing national park situated in succulent thicket. This unique veld type is endemic to the Eastern Cape, and forms an important centre of endemism for small succulents and geophytes which comprise the subdominant component of the vegetation. It is regarded as the most threatened vegetation type in the Eastern Cape, as much of it has been severely degraded by farming activities and its rate of regeneration is very low. Thus the AENP represents an important sanctuary for certain species. However, large herbivores, particularly elephants, pose a further threat to the vegetation, and areas from which elephants have been excluded in the park (botanical reserves) have been shown to be more speciesrich than the surrounding vegetation. Most elephant-impact studies have focussed on the large shrub component of the vegetation, and only preliminary studies have been done in AENP to date. As the elephant population continues to grow, there is pressure to utilise the botanical reserves to increase the amount of available grazing. It is thus important that the botanical reserve system be highly effective and efficient in terms of area. Existing botanical reserves were established ad hoc and are therefore not necessarily optimal in this regard. An iterative reserve-selection algorithm was used to maximise plant species conservation in the most efficient area.
- Full Text:
- Date Issued: 1998
Analysis of macrolide antibiotics
- Kanfer, Isadore, Skinner, Michael F, Walker, Roderick B
- Authors: Kanfer, Isadore , Skinner, Michael F , Walker, Roderick B
- Date: 1998
- Language: English
- Type: Article , text
- Identifier: vital:7011 , http://hdl.handle.net/10962/d1008394 , http://www.sciencedirect.com/science/article/pii/S0021967398002763
- Description: The following macrolide antibiotics have been covered in this review: erythromycin and its related substances, azithromycin, clarithromycin, dirithromycin, roxithromycin, flurithromycin, josamycin, rokitamycin, kitasamycin, mycinamycin, mirosamycin, oleandomycin, rosaramicin, spiramycin and tylosin. The application of various thin-layer chromatography, paper chromatography, gas chromatography, high-performance liquid chromatography and capillary zone electrophoresis procedures for their analysis are described. These techniques have been applied to the separation and quantitative analysis of the macrolides in fermentation media, purity assessment of raw materials, assay of pharmaceutical dosage forms and the measurement of clinically useful macrolide antibiotics in biological samples such as blood, plasma, serum, urine and tissues. Data relating to the chromatographic behaviour of some macrolide antibiotics as well as the various detection methods used, such as bioautography, UV spectrophotometry, fluorometry, electrochemical detection, chemiluminescence and mass spectrometry techniques are also included.
- Full Text:
- Date Issued: 1998
- Authors: Kanfer, Isadore , Skinner, Michael F , Walker, Roderick B
- Date: 1998
- Language: English
- Type: Article , text
- Identifier: vital:7011 , http://hdl.handle.net/10962/d1008394 , http://www.sciencedirect.com/science/article/pii/S0021967398002763
- Description: The following macrolide antibiotics have been covered in this review: erythromycin and its related substances, azithromycin, clarithromycin, dirithromycin, roxithromycin, flurithromycin, josamycin, rokitamycin, kitasamycin, mycinamycin, mirosamycin, oleandomycin, rosaramicin, spiramycin and tylosin. The application of various thin-layer chromatography, paper chromatography, gas chromatography, high-performance liquid chromatography and capillary zone electrophoresis procedures for their analysis are described. These techniques have been applied to the separation and quantitative analysis of the macrolides in fermentation media, purity assessment of raw materials, assay of pharmaceutical dosage forms and the measurement of clinically useful macrolide antibiotics in biological samples such as blood, plasma, serum, urine and tissues. Data relating to the chromatographic behaviour of some macrolide antibiotics as well as the various detection methods used, such as bioautography, UV spectrophotometry, fluorometry, electrochemical detection, chemiluminescence and mass spectrometry techniques are also included.
- Full Text:
- Date Issued: 1998
Reproductive behaviour of the skunk clownfish, Amphiprion akallopisos, under captive conditions
- Authors: Haschick, Rory Dean
- Date: 1998
- Subjects: Anemonefishes -- Spawning , Amphiprion -- Reproduction , Fishes -- Reproduction , Hatchery fishes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5316 , http://hdl.handle.net/10962/d1005161 , Anemonefishes -- Spawning , Amphiprion -- Reproduction , Fishes -- Reproduction , Hatchery fishes
- Description: The objectives of the study were to determine whether or not behaviour could be used to predict spawning in Amphiprion akallopisos, and to document the behaviour of this species under various environmental conditions in captivity. The spawning behaviour of A. akallopisos was studied and quantified. Three behaviour patterns - belly touching, nest cleaning by the female and mutual nest cleaning (by the male and the female) were identified as predictors for spawning. The reproductive behaviour of A.akallopisos under three photoperiods was investigated. The photoperiods were: 14L:10D, 10hr15minL:13hr45minD and a natural photoperiod cycle condensed into three months. A. akallopisos maintained under 14 L:10D exhibited a significantly higher frequency and duration of chasing, nest cleaning and total interaction compared to fish kept under 10hr15minL:13hr45minD. A photoperiod of 14L:10D was selected for further studies. As manipulation of photoperiod did not induce spawning, GnRHa was administered to the fish in the diet at levels of 10, 20, 40 and 80 μg/kg BW. Control groups were fed untreated food. None of the dosages were successful in inducing spawning, or spawning behaviour in A. akallopisos. It is possible that the method of hormone application was not suitable for this species. It is also possible that behaviour may regulate blood hormone levels as opposed to endocrine status influencing behaviour. In the third trial, A. akallopisos was maintained with, and without sea anemones in order to determine whether or not anemone hosts are necessary for spawning. The presence of anemones did not induce spawning and A. akallopisos kept without anemones exhibited significantly more interactive behaviour than fish kept with hosts. Spawning of A. akallopisos at a later date without anemones suggests that anemones are not necessary for spawning in A. akallopisos. Light intensity was investigated as a cue for spawning. The reproductive behaviour of A. akallopisos was then studied under light intensities of 4.16 x 10¹⁵ quanta.sec⁻¹.cm⁻², 8.85 x 10¹⁵ quanta.sec⁻¹.cm⁻² and this intensity plus natural light. Spawning occurred mainly under 8.85 x 10¹⁵ quanta.sec⁻¹.cm⁻². Fish maintained under this light intensity exhibited significantly more of nest cleaning behaviour in terms of frequency and duration than fish maintained under low light intensity. A minimum light intensity of 8.85 x 10¹⁵ quanta. sec⁻¹.cm⁻² is recommended for conditioning of this species. This study can be of practical relevance to hatchery managers who can use the methods developed and record predictors for spawning in A. akallopisos and other Amphiprion species. In this way imminence of spawning may be estimated. Most importantly, the study also has academic merit as little work has been undertaken in this field. Although the observational method used in this study was adequate for the purposes of the investigation, future work of this nature should incorporate other methods of documenting gonadal development such as gonadal staging and GSI in order to obtain more conclusive results.
- Full Text:
- Date Issued: 1998
- Authors: Haschick, Rory Dean
- Date: 1998
- Subjects: Anemonefishes -- Spawning , Amphiprion -- Reproduction , Fishes -- Reproduction , Hatchery fishes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5316 , http://hdl.handle.net/10962/d1005161 , Anemonefishes -- Spawning , Amphiprion -- Reproduction , Fishes -- Reproduction , Hatchery fishes
- Description: The objectives of the study were to determine whether or not behaviour could be used to predict spawning in Amphiprion akallopisos, and to document the behaviour of this species under various environmental conditions in captivity. The spawning behaviour of A. akallopisos was studied and quantified. Three behaviour patterns - belly touching, nest cleaning by the female and mutual nest cleaning (by the male and the female) were identified as predictors for spawning. The reproductive behaviour of A.akallopisos under three photoperiods was investigated. The photoperiods were: 14L:10D, 10hr15minL:13hr45minD and a natural photoperiod cycle condensed into three months. A. akallopisos maintained under 14 L:10D exhibited a significantly higher frequency and duration of chasing, nest cleaning and total interaction compared to fish kept under 10hr15minL:13hr45minD. A photoperiod of 14L:10D was selected for further studies. As manipulation of photoperiod did not induce spawning, GnRHa was administered to the fish in the diet at levels of 10, 20, 40 and 80 μg/kg BW. Control groups were fed untreated food. None of the dosages were successful in inducing spawning, or spawning behaviour in A. akallopisos. It is possible that the method of hormone application was not suitable for this species. It is also possible that behaviour may regulate blood hormone levels as opposed to endocrine status influencing behaviour. In the third trial, A. akallopisos was maintained with, and without sea anemones in order to determine whether or not anemone hosts are necessary for spawning. The presence of anemones did not induce spawning and A. akallopisos kept without anemones exhibited significantly more interactive behaviour than fish kept with hosts. Spawning of A. akallopisos at a later date without anemones suggests that anemones are not necessary for spawning in A. akallopisos. Light intensity was investigated as a cue for spawning. The reproductive behaviour of A. akallopisos was then studied under light intensities of 4.16 x 10¹⁵ quanta.sec⁻¹.cm⁻², 8.85 x 10¹⁵ quanta.sec⁻¹.cm⁻² and this intensity plus natural light. Spawning occurred mainly under 8.85 x 10¹⁵ quanta.sec⁻¹.cm⁻². Fish maintained under this light intensity exhibited significantly more of nest cleaning behaviour in terms of frequency and duration than fish maintained under low light intensity. A minimum light intensity of 8.85 x 10¹⁵ quanta. sec⁻¹.cm⁻² is recommended for conditioning of this species. This study can be of practical relevance to hatchery managers who can use the methods developed and record predictors for spawning in A. akallopisos and other Amphiprion species. In this way imminence of spawning may be estimated. Most importantly, the study also has academic merit as little work has been undertaken in this field. Although the observational method used in this study was adequate for the purposes of the investigation, future work of this nature should incorporate other methods of documenting gonadal development such as gonadal staging and GSI in order to obtain more conclusive results.
- Full Text:
- Date Issued: 1998
Ecological interactions on a rocky shore : the control of macroalgal distribution by intertidal grazers
- Whittington-Jones, Kevin John
- Authors: Whittington-Jones, Kevin John
- Date: 1998
- Subjects: Limpets -- South Africa , Mollusks -- Ecology , Mollusks -- Feeding and feeds , Mollusks -- South Africa , Cryptogams , Cryptogams -- South Africa , Algae -- Control , Algae -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5665 , http://hdl.handle.net/10962/d1005350 , Limpets -- South Africa , Mollusks -- Ecology , Mollusks -- Feeding and feeds , Mollusks -- South Africa , Cryptogams , Cryptogams -- South Africa , Algae -- Control , Algae -- South Africa
- Description: The aim of the present study was to determine the potential impact of intertidal grazers on the distribution of macro algae on the south coast of South Africa. Particular attention was paid to the large patellid limpet, Patella oculus, which is found thoughout the intertidal zone. Studies of gut contents revealed that Patella oculus was capable of ingesting not only the thallus of foliose (eg. Ulva spp.) and encrusting coralline macroalgae, but also spores and diatoms. The inclusion of these relatively small particles in the diet was surprising, as electron micrographs of the radula of P.oculus revealed that it is typically docoglossan in structure. Such radulae are thought to be poorly suited for collecting small food particles. Sand made up a significantly higher proportion of the gut contents than other particles at all shore heights, which suggests that P.oculus might be capable of excavating the rocky substratum, or of sweeping up sand, while searching for food. Analysis of the gut contents of other local herbivorous molluscs, was also carried out. These species included the winkles, Oxystele variegata and O.sinensis, and the small pulmonate limpets, Siphonaria concinna, S.capensis, and S.serrata. The guts of all species contained mainly spores and diatoms, although small fragments of Ulva sp. were found. The population structure of Patella oculus was investigated at two sites, Cannon Rocks and Old Woman's River. At Cannon Rocks, mean shell length of low-shore animals was significantly lower than that of both mid- and high-shore animals, while at Old Woman's River, no significant difference was found among shore heights. A regression equation for In (shell length) vs In (dry weight) was calculated, and based on length data, the biomass density (g dry mass.m⁻²) of P.oculus at Old Woman's River was estimated. Values ranged from 2.8 on the low- and midshore to 0.37 on the high-shore. A manipulative field experiment was used to determine the impact of mesograzers and macrograzers (such as Patella oculus) on the distribution of intertidal macro algae on the mid- and low-shore at Old Woman's River. Grazers were excluded using mesh cages (mesh size = 3mm), in two separate experiments, one in winter and the other in spring. Percentage cover of macroalgal species and sessile invertebrates was estimated at approximately 6 week intervals for up to 3 months. MANOV A showed that treatments did not significantly affect cover of macroalgae or barnacles during winter. However, towards the end of the spring experiment (midshore only) cover of barnacles and green foliose turfs did increase in those plots from which mesograzers and/or macro grazers were excluded. The failure of the statistical tests to detect significant differences at some time intervals may have been caused by high levels of variation among replicates. This suggests that factors other than grazing are of overriding importance in determining the distribution of local macroalgae. The existence of a possible symbiotic relationship between Patella oculus and the red foliose alga, Gelidium pristoides, was investigated. The availability of various substratum types, including rock, limpet shells, barnacles etc., and the proportion of the total cover of G.pristoides on each, was calculated. It was shown that a significantly higher proportion of the alga grew on limpet shells, although the availability of this substratum type was low. It is thought that the aggressive behaviour of P.oculus prevents all but juvenile Patella longicosta from grazing on its shell, thus providing a refuge from grazing for G.pristoides.
- Full Text:
- Date Issued: 1998
- Authors: Whittington-Jones, Kevin John
- Date: 1998
- Subjects: Limpets -- South Africa , Mollusks -- Ecology , Mollusks -- Feeding and feeds , Mollusks -- South Africa , Cryptogams , Cryptogams -- South Africa , Algae -- Control , Algae -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5665 , http://hdl.handle.net/10962/d1005350 , Limpets -- South Africa , Mollusks -- Ecology , Mollusks -- Feeding and feeds , Mollusks -- South Africa , Cryptogams , Cryptogams -- South Africa , Algae -- Control , Algae -- South Africa
- Description: The aim of the present study was to determine the potential impact of intertidal grazers on the distribution of macro algae on the south coast of South Africa. Particular attention was paid to the large patellid limpet, Patella oculus, which is found thoughout the intertidal zone. Studies of gut contents revealed that Patella oculus was capable of ingesting not only the thallus of foliose (eg. Ulva spp.) and encrusting coralline macroalgae, but also spores and diatoms. The inclusion of these relatively small particles in the diet was surprising, as electron micrographs of the radula of P.oculus revealed that it is typically docoglossan in structure. Such radulae are thought to be poorly suited for collecting small food particles. Sand made up a significantly higher proportion of the gut contents than other particles at all shore heights, which suggests that P.oculus might be capable of excavating the rocky substratum, or of sweeping up sand, while searching for food. Analysis of the gut contents of other local herbivorous molluscs, was also carried out. These species included the winkles, Oxystele variegata and O.sinensis, and the small pulmonate limpets, Siphonaria concinna, S.capensis, and S.serrata. The guts of all species contained mainly spores and diatoms, although small fragments of Ulva sp. were found. The population structure of Patella oculus was investigated at two sites, Cannon Rocks and Old Woman's River. At Cannon Rocks, mean shell length of low-shore animals was significantly lower than that of both mid- and high-shore animals, while at Old Woman's River, no significant difference was found among shore heights. A regression equation for In (shell length) vs In (dry weight) was calculated, and based on length data, the biomass density (g dry mass.m⁻²) of P.oculus at Old Woman's River was estimated. Values ranged from 2.8 on the low- and midshore to 0.37 on the high-shore. A manipulative field experiment was used to determine the impact of mesograzers and macrograzers (such as Patella oculus) on the distribution of intertidal macro algae on the mid- and low-shore at Old Woman's River. Grazers were excluded using mesh cages (mesh size = 3mm), in two separate experiments, one in winter and the other in spring. Percentage cover of macroalgal species and sessile invertebrates was estimated at approximately 6 week intervals for up to 3 months. MANOV A showed that treatments did not significantly affect cover of macroalgae or barnacles during winter. However, towards the end of the spring experiment (midshore only) cover of barnacles and green foliose turfs did increase in those plots from which mesograzers and/or macro grazers were excluded. The failure of the statistical tests to detect significant differences at some time intervals may have been caused by high levels of variation among replicates. This suggests that factors other than grazing are of overriding importance in determining the distribution of local macroalgae. The existence of a possible symbiotic relationship between Patella oculus and the red foliose alga, Gelidium pristoides, was investigated. The availability of various substratum types, including rock, limpet shells, barnacles etc., and the proportion of the total cover of G.pristoides on each, was calculated. It was shown that a significantly higher proportion of the alga grew on limpet shells, although the availability of this substratum type was low. It is thought that the aggressive behaviour of P.oculus prevents all but juvenile Patella longicosta from grazing on its shell, thus providing a refuge from grazing for G.pristoides.
- Full Text:
- Date Issued: 1998
Preliminary investigation of the molecular pathogenicity determinants of Xanthomonas campestris pv. zeae
- Authors: Downing, T G
- Date: 1998
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4066 , http://hdl.handle.net/10962/d1004922
- Description: Xanthomonas campestris pv. zeae was shown to posses a vast range of potential plant cell wall degrading enzymes including at least one protease, a carboxymethylcellulase, pectin lyase, polygalacturonase and a B-endoglucanase. Replicon stability and transfer system efficiencies were determined for a range of oriC, and oriT -tra combinations, and suitable vectors were constructed and identified for insertional inactivation by homologous recombination. Ideal suicide replicons were found to be pACYC184 and p15A, while P, Wand Q group replicons were supported by X campestris pv. zeae. Group P and group N transfer systems were shown to be highly efficient in intra-genus matings between Escherichia coli and X campestris pv. zeae, with the exception of P-tra systems in trans for the delivery of Tn5. Various cloning vectors were tested for stability and mobility. Tn5 was shown to transpose at high frequencies into the genome of the bacterial plant pathogen, and insertion was relatively random. Suitable screening assays were established to allow rapid isolation of mutants with potential virulence or pathogenic deviations, after mutagenesis. Two non-pathogenic mutants were identified, one of which was a putative hrp·, while the other was a leaky virulence. A single mutant showing 40% reduced protease activity was also shown to exhibit reduced virulence indicating a minor role for the protease in pathogenicity. The majority of virulence mutants showed altered growth in different levels of nutritional availability and complexity. Nutritional viability (the ability to acquire and use nutrients at a sufficient rate to grow fast enough to overcome host defences) was shown to be essential for virulence and possibly pathogenicity. Wild-type in-planta behaviour was analysed and growth and spread patterns typical for pathogenic response identified. Chief amongst these was the requirement for a threshold level of cells per leaf area or length, before symptoms could develop. Occlusion of vascular bundles was shown not to be the primary factor in the pathogenicity of X campestris pv. zeae. Threshold levels for lesion development indicate the absence of a diffusable lesion forming element, and possibly the requirement of cell density for induction of certain functions. , KMBT_363
- Full Text:
- Date Issued: 1998
- Authors: Downing, T G
- Date: 1998
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4066 , http://hdl.handle.net/10962/d1004922
- Description: Xanthomonas campestris pv. zeae was shown to posses a vast range of potential plant cell wall degrading enzymes including at least one protease, a carboxymethylcellulase, pectin lyase, polygalacturonase and a B-endoglucanase. Replicon stability and transfer system efficiencies were determined for a range of oriC, and oriT -tra combinations, and suitable vectors were constructed and identified for insertional inactivation by homologous recombination. Ideal suicide replicons were found to be pACYC184 and p15A, while P, Wand Q group replicons were supported by X campestris pv. zeae. Group P and group N transfer systems were shown to be highly efficient in intra-genus matings between Escherichia coli and X campestris pv. zeae, with the exception of P-tra systems in trans for the delivery of Tn5. Various cloning vectors were tested for stability and mobility. Tn5 was shown to transpose at high frequencies into the genome of the bacterial plant pathogen, and insertion was relatively random. Suitable screening assays were established to allow rapid isolation of mutants with potential virulence or pathogenic deviations, after mutagenesis. Two non-pathogenic mutants were identified, one of which was a putative hrp·, while the other was a leaky virulence. A single mutant showing 40% reduced protease activity was also shown to exhibit reduced virulence indicating a minor role for the protease in pathogenicity. The majority of virulence mutants showed altered growth in different levels of nutritional availability and complexity. Nutritional viability (the ability to acquire and use nutrients at a sufficient rate to grow fast enough to overcome host defences) was shown to be essential for virulence and possibly pathogenicity. Wild-type in-planta behaviour was analysed and growth and spread patterns typical for pathogenic response identified. Chief amongst these was the requirement for a threshold level of cells per leaf area or length, before symptoms could develop. Occlusion of vascular bundles was shown not to be the primary factor in the pathogenicity of X campestris pv. zeae. Threshold levels for lesion development indicate the absence of a diffusable lesion forming element, and possibly the requirement of cell density for induction of certain functions. , KMBT_363
- Full Text:
- Date Issued: 1998