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
New developments in the methodology available for the assessment of topical corticosteroid-induced skin blanching
- Haigh, John M, Smith, Eric W, Maibach, Howard I
- Authors: Haigh, John M , Smith, Eric W , Maibach, Howard I
- Date: 1998
- Language: English
- Type: text , Article
- Identifier: vital:6384 , http://hdl.handle.net/10962/d1006305
- Description: Since the publication of the previous edition of this book there have been considerable developments and controversy in the field of topical corticosteroid bioequivalence assessment. There has been considerable discussion in the literature concerning the use of the Minolta chromameter for the measurement of corticosteroid-induced skin blanching, as it is believed this instrument would produce more objective results than the visual grading procedure. These efforts culminated in the release of a guidance document from the Food and Drug Administration (FDA) detailing the procedures to be followed for the determination of topical corticosteroid bioequivalence using the chromameter. Since the promulgation of this document there have been challenges on the validity and scientific merit of the documented procedures, and recently the FDA itself conceded that it may be necessary to redefine some of the protocol evaluations. This chapter attempts to redefine the current standing of the two methods of response assessment.
- Full Text:
- Date Issued: 1998
- Authors: Haigh, John M , Smith, Eric W , Maibach, Howard I
- Date: 1998
- Language: English
- Type: text , Article
- Identifier: vital:6384 , http://hdl.handle.net/10962/d1006305
- Description: Since the publication of the previous edition of this book there have been considerable developments and controversy in the field of topical corticosteroid bioequivalence assessment. There has been considerable discussion in the literature concerning the use of the Minolta chromameter for the measurement of corticosteroid-induced skin blanching, as it is believed this instrument would produce more objective results than the visual grading procedure. These efforts culminated in the release of a guidance document from the Food and Drug Administration (FDA) detailing the procedures to be followed for the determination of topical corticosteroid bioequivalence using the chromameter. Since the promulgation of this document there have been challenges on the validity and scientific merit of the documented procedures, and recently the FDA itself conceded that it may be necessary to redefine some of the protocol evaluations. This chapter attempts to redefine the current standing of the two methods of response assessment.
- Full Text:
- Date Issued: 1998
Pension payouts, periodic marketing and the continuance of urban dependence in rural South Africa
- Fox, Roddy C, Nel, Etienne L
- Authors: Fox, Roddy C , Nel, Etienne L
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6681 , http://hdl.handle.net/10962/d1006675
- Description: The former homeland areas of South Africa are characterised by extreme poverty, high levels of urban dependence, a reliance on pensions and low levels of agricultural production. This paper is based on a case-study of the Eastern Cape province and details rural realities, the importance of pensions and the constraints which face current plans to develop and expand the periodic marketing network.
- Full Text: false
- Date Issued: 1998
- Authors: Fox, Roddy C , Nel, Etienne L
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6681 , http://hdl.handle.net/10962/d1006675
- Description: The former homeland areas of South Africa are characterised by extreme poverty, high levels of urban dependence, a reliance on pensions and low levels of agricultural production. This paper is based on a case-study of the Eastern Cape province and details rural realities, the importance of pensions and the constraints which face current plans to develop and expand the periodic marketing network.
- Full Text: false
- Date Issued: 1998
Regionalism in marine biology: the convergence of ecology, economics and politics in South Africa
- McQuaid, Christopher D, Payne, A I L
- Authors: McQuaid, Christopher D , Payne, A I L
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6938 , http://hdl.handle.net/10962/d1011960
- Description: The South African coast includes biogeographic provinces which are quite distinct in their abilities to sustain exploitation and in the types of exploitation they experience. As a result, no single region can act as a model for the management of living resources around the entire coast. Instead, appropriate management must rest on regionally based research. Past research in marine biology focused on the west coast with much less attention being given to the east and south coasts, where non-commercial, subsistence-level fisheries predominate. A partial decentralisation of research focus is essential. This requires commitment from national-level research bodies and some certainty about at least medium-term funding. This paper addresses the convergence of ecology, economics and politics in South Africa and illustrates the direct relevance that fundamental or basic research can have to socioeconomic problems. Recruitment of the resource; Geographical variation in biological processes; State of research policy; Promise of regulations.
- Full Text: false
- Date Issued: 1998
- Authors: McQuaid, Christopher D , Payne, A I L
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6938 , http://hdl.handle.net/10962/d1011960
- Description: The South African coast includes biogeographic provinces which are quite distinct in their abilities to sustain exploitation and in the types of exploitation they experience. As a result, no single region can act as a model for the management of living resources around the entire coast. Instead, appropriate management must rest on regionally based research. Past research in marine biology focused on the west coast with much less attention being given to the east and south coasts, where non-commercial, subsistence-level fisheries predominate. A partial decentralisation of research focus is essential. This requires commitment from national-level research bodies and some certainty about at least medium-term funding. This paper addresses the convergence of ecology, economics and politics in South Africa and illustrates the direct relevance that fundamental or basic research can have to socioeconomic problems. Recruitment of the resource; Geographical variation in biological processes; State of research policy; Promise of regulations.
- Full Text: false
- Date Issued: 1998
Research cruise of the Scandinavian/South African Antarctic expedition, December 1997 to February 1998
- Froneman, P William, Pakhomov, E A, Turner, D, Abrahamson, K, Karlsson, B, Godhe, A, Bertilsson, S, Graneli, W, Carlsson, P, Wangberg, S, Wulff, A, Croot, P, Andersson, K, Balarin, Marianne G, Wedborg, M, Persson, T, Rasmus, K, Ozturk, M, David, R
- Authors: Froneman, P William , Pakhomov, E A , Turner, D , Abrahamson, K , Karlsson, B , Godhe, A , Bertilsson, S , Graneli, W , Carlsson, P , Wangberg, S , Wulff, A , Croot, P , Andersson, K , Balarin, Marianne G , Wedborg, M , Persson, T , Rasmus, K , Ozturk, M , David, R
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6934 , http://hdl.handle.net/10962/d1011955
- Description: Focuses on the Scandinavian/South African Antarctic expedition conducted between December 4, 1997 to February 6, 1998 which determined the role of Southern Ocean in the global carbon cycle in physical and biological oceanographic studies. Aims of the expedition; Underway sampling conducted; Biological results of the expedition; Conclusions.
- Full Text: false
- Date Issued: 1998
- Authors: Froneman, P William , Pakhomov, E A , Turner, D , Abrahamson, K , Karlsson, B , Godhe, A , Bertilsson, S , Graneli, W , Carlsson, P , Wangberg, S , Wulff, A , Croot, P , Andersson, K , Balarin, Marianne G , Wedborg, M , Persson, T , Rasmus, K , Ozturk, M , David, R
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6934 , http://hdl.handle.net/10962/d1011955
- Description: Focuses on the Scandinavian/South African Antarctic expedition conducted between December 4, 1997 to February 6, 1998 which determined the role of Southern Ocean in the global carbon cycle in physical and biological oceanographic studies. Aims of the expedition; Underway sampling conducted; Biological results of the expedition; Conclusions.
- Full Text: false
- Date Issued: 1998
Surface distribution of microphytoplankton of the south-west Indian Ocean along a repeat transect between Cape Town and the Prince Edward Islands
- Froneman, P William, Pakhomov, E A, Meaton, V
- Authors: Froneman, P William , Pakhomov, E A , Meaton, V
- Date: 1998
- Language: English
- Type: text , Article
- Identifier: vital:6933 , http://hdl.handle.net/10962/d1011953
- Description: Surface chlorophyll-a (chl-a) concentrations, microphytoplankton (>20 μm) species composition and distribution along a repeat transect between Cape Town and the Prince Edward Islands were investigated in early austral autumn (April/May) 1996. Samples were collected at approximately 30 nautical mile intervals for the analysis of size-fractionated chl-a and the identification and enumeration of microphytoplankton species. Peaks in total chl-a (>1 μg 1 [superscript -1]) were recorded at the Subtropical Convergence (STC), at the Sub-Antarctic Front (SAF) and in the waters surrounding the Prince Edward Islands. In addition, a minor peak in chl-a concentration was recorded in the continental shelf waters. At stations where elevated chl-a concentrations were recorded, microphytoplankton generally formed a substantial contribution (-10%) to total chlorophyll. Outside these regions, total chlorophyll concentrations were lower (<0.9 μg 1 [superscript -1]) and almost entirely dominated by nano- and picophytoplankton, which contributed >95% of the total. Microphytoplankton species composition along both transects were dominated by chain-forming species of the genera Chaetoceros (mainly C. neglectum, C. peruvianus and C. constrictus), Nitzschia spp. and Pseudoeunotia doliolus. Cluster and ordination analysis based on species composition identified five distinct microphytoplankton assemblages, which were closely associated with the different water masses in the region between Cape Town and the Prince Edward Islands. The microphytoplankton species composition and biogeographic zones identified during this investigation are in general agreement with similar studies conducted in the south-west Indian Ocean during the austral summer, which suggests that there are little seasonal trends in both the microphytoplankton species composition and biogeographic zonation.
- Full Text:
- Date Issued: 1998
- Authors: Froneman, P William , Pakhomov, E A , Meaton, V
- Date: 1998
- Language: English
- Type: text , Article
- Identifier: vital:6933 , http://hdl.handle.net/10962/d1011953
- Description: Surface chlorophyll-a (chl-a) concentrations, microphytoplankton (>20 μm) species composition and distribution along a repeat transect between Cape Town and the Prince Edward Islands were investigated in early austral autumn (April/May) 1996. Samples were collected at approximately 30 nautical mile intervals for the analysis of size-fractionated chl-a and the identification and enumeration of microphytoplankton species. Peaks in total chl-a (>1 μg 1 [superscript -1]) were recorded at the Subtropical Convergence (STC), at the Sub-Antarctic Front (SAF) and in the waters surrounding the Prince Edward Islands. In addition, a minor peak in chl-a concentration was recorded in the continental shelf waters. At stations where elevated chl-a concentrations were recorded, microphytoplankton generally formed a substantial contribution (-10%) to total chlorophyll. Outside these regions, total chlorophyll concentrations were lower (<0.9 μg 1 [superscript -1]) and almost entirely dominated by nano- and picophytoplankton, which contributed >95% of the total. Microphytoplankton species composition along both transects were dominated by chain-forming species of the genera Chaetoceros (mainly C. neglectum, C. peruvianus and C. constrictus), Nitzschia spp. and Pseudoeunotia doliolus. Cluster and ordination analysis based on species composition identified five distinct microphytoplankton assemblages, which were closely associated with the different water masses in the region between Cape Town and the Prince Edward Islands. The microphytoplankton species composition and biogeographic zones identified during this investigation are in general agreement with similar studies conducted in the south-west Indian Ocean during the austral summer, which suggests that there are little seasonal trends in both the microphytoplankton species composition and biogeographic zonation.
- Full Text:
- Date Issued: 1998
Symplastic solute transport and avocado fruit development : a decline in cytokinin/ABA ratio is related to appearance of the Hass small fruit variant
- Moore-Gordon, Clive S, Cowan, Keith A, Bertling, Isa, Botha, Christiaan E J, Cross, Robin H M
- Authors: Moore-Gordon, Clive S , Cowan, Keith A , Bertling, Isa , Botha, Christiaan E J , Cross, Robin H M
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6525 , http://hdl.handle.net/10962/d1005959
- Description: Studies on the effect of fruit size on endogenous ABA and isopentenyladenine (iP) in developing avocado (Persea americana Mill. cv. Hass) fruit revealed that ABA content was negatively correlated with fruit size whilst the iP/ABA ratio showed a linear relationship with increasing size of fruit harvested 226 d after full bloom. The effect of this change in hormone balance on the relationship between symplastic solute transport and appearance of the small fruit variant was examined following manipulation of the endogenous cytokinin (CK)/ABA ratio. Application of ABA caused seed coat senescence and retarded fruit growth but these effects were absent in fruit treated with equal amounts of ABA plus iP. Thus, the underlying physiological mechanisms associated with ABA-induced retardation of Hass avocado fruit growth appeared to be inextricably linked to a decline in CK content and included: diminution of mesocarp and seed coat plasmodesmatal branching, gating of mesocarp and seed coat plasmodesmata by deposition of electron dense material in the neck region, abolishment of the electrochemical gradient between mesocarp and seed coat parenchyma, and arrest of cell-to-cell chemical communication.
- Full Text:
- Date Issued: 1998
- Authors: Moore-Gordon, Clive S , Cowan, Keith A , Bertling, Isa , Botha, Christiaan E J , Cross, Robin H M
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6525 , http://hdl.handle.net/10962/d1005959
- Description: Studies on the effect of fruit size on endogenous ABA and isopentenyladenine (iP) in developing avocado (Persea americana Mill. cv. Hass) fruit revealed that ABA content was negatively correlated with fruit size whilst the iP/ABA ratio showed a linear relationship with increasing size of fruit harvested 226 d after full bloom. The effect of this change in hormone balance on the relationship between symplastic solute transport and appearance of the small fruit variant was examined following manipulation of the endogenous cytokinin (CK)/ABA ratio. Application of ABA caused seed coat senescence and retarded fruit growth but these effects were absent in fruit treated with equal amounts of ABA plus iP. Thus, the underlying physiological mechanisms associated with ABA-induced retardation of Hass avocado fruit growth appeared to be inextricably linked to a decline in CK content and included: diminution of mesocarp and seed coat plasmodesmatal branching, gating of mesocarp and seed coat plasmodesmata by deposition of electron dense material in the neck region, abolishment of the electrochemical gradient between mesocarp and seed coat parenchyma, and arrest of cell-to-cell chemical communication.
- Full Text:
- Date Issued: 1998
The end of apartheid and the organisation of work in manufacturing plants in South Africa's Eastern Cape Province
- Authors: Smith, M R , Wood, G T
- Date: 1998
- Language: English
- Type: text , Article
- Identifier: vital:6319 , http://hdl.handle.net/10962/d1011313
- Description: The election of 1994 radically changed the environment within which management chose its labour control policies. Prior to the change of government in 1994 plant practices were shaped by the fact of substantial protection against foreign competition, widespread illiteracy, and a set of laws and policies that offered few protections for individual workers or organised labour. Since the change in government the political and legal environment has substantially changed. In this paper we report on management practices before and after the political changes in South Africa in a set of plants in a part of the country where many of the current difficulties of the South African economy exist in a fairly extreme form.
- Full Text:
- Date Issued: 1998
- Authors: Smith, M R , Wood, G T
- Date: 1998
- Language: English
- Type: text , Article
- Identifier: vital:6319 , http://hdl.handle.net/10962/d1011313
- Description: The election of 1994 radically changed the environment within which management chose its labour control policies. Prior to the change of government in 1994 plant practices were shaped by the fact of substantial protection against foreign competition, widespread illiteracy, and a set of laws and policies that offered few protections for individual workers or organised labour. Since the change in government the political and legal environment has substantially changed. In this paper we report on management practices before and after the political changes in South Africa in a set of plants in a part of the country where many of the current difficulties of the South African economy exist in a fairly extreme form.
- Full Text:
- Date Issued: 1998
The requirements for accurate analysis of pharmaceutical research at South African Universities
- Haigh, John M, Smith, Eric W
- Authors: Haigh, John M , Smith, Eric W
- Date: 1998
- Language: English
- Type: text , Article
- Identifier: vital:6367 , http://hdl.handle.net/10962/d1006067
- Description: International Pharmaceutical Abstracts is a valuable database for pharmaceutical research, although the multisiciplinary nature of this field implies that the database should only be the starting point of a search. This database is totally inappropriate for comparing outputs of individual pharmacy teaching institutions.
- Full Text:
- Date Issued: 1998
- Authors: Haigh, John M , Smith, Eric W
- Date: 1998
- Language: English
- Type: text , Article
- Identifier: vital:6367 , http://hdl.handle.net/10962/d1006067
- Description: International Pharmaceutical Abstracts is a valuable database for pharmaceutical research, although the multisiciplinary nature of this field implies that the database should only be the starting point of a search. This database is totally inappropriate for comparing outputs of individual pharmacy teaching institutions.
- Full Text:
- Date Issued: 1998
The third Marion Island oceanographic study (MIOS III) conducted during April and May 1998
- Froneman, Pierre William, Ansorge, Isabelle J
- Authors: Froneman, Pierre William , Ansorge, Isabelle J
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6937 , http://hdl.handle.net/10962/d1011959
- Description: Focuses on the third Marion Island Oceanographic Study (MIOS III). Objectives of the study; Details on the results; Conclusions.
- Full Text: false
- Date Issued: 1998
- Authors: Froneman, Pierre William , Ansorge, Isabelle J
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6937 , http://hdl.handle.net/10962/d1011959
- Description: Focuses on the third Marion Island Oceanographic Study (MIOS III). Objectives of the study; Details on the results; Conclusions.
- Full Text: false
- Date Issued: 1998
Types of case study work : a conceptual framework for case-based research
- Authors: Edwards, David J A
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6240 , http://hdl.handle.net/10962/d1007852
- Description: This paper describes a conceptual framework for understanding the phases of casebased research. Case-based strategies in research are widely used in case study methodology as well as in a number of qualitative methodologies including grounded theory development, phenomenological research method and psychotherapy process research. The epistemological principles upon which casebased research is based are fundamentally different those which inform groupbased research using quantitative multivariate statistics. The case-based research process is divided into three general phases: descriptive, theoretical-heuristic, and theory-testing. Each of these phases is subdivided into two categories. The aims and epistemological principles related to each phase are discussed and illustrated with examples from contemporary research. The principles for establishing validity in case-base research are also reviewed and, in order to assist research students and supervisors, some common pitfalls are noted. The paper shows that rigorous work with single cases or series of cases using case-based principles and methodology is indeed, as Bromley (1986) claimed, "the bedrock of scientific investigation".
- Full Text:
- Date Issued: 1998
- Authors: Edwards, David J A
- Date: 1998
- Language: English
- Type: Article
- Identifier: vital:6240 , http://hdl.handle.net/10962/d1007852
- Description: This paper describes a conceptual framework for understanding the phases of casebased research. Case-based strategies in research are widely used in case study methodology as well as in a number of qualitative methodologies including grounded theory development, phenomenological research method and psychotherapy process research. The epistemological principles upon which casebased research is based are fundamentally different those which inform groupbased research using quantitative multivariate statistics. The case-based research process is divided into three general phases: descriptive, theoretical-heuristic, and theory-testing. Each of these phases is subdivided into two categories. The aims and epistemological principles related to each phase are discussed and illustrated with examples from contemporary research. The principles for establishing validity in case-base research are also reviewed and, in order to assist research students and supervisors, some common pitfalls are noted. The paper shows that rigorous work with single cases or series of cases using case-based principles and methodology is indeed, as Bromley (1986) claimed, "the bedrock of scientific investigation".
- Full Text:
- Date Issued: 1998
Think: A Review of International Struggles
- Date: 1998-01
- Subjects: Government, Resistance to -- South Africa , South Africa -- History -- 20th century , South Africa -- Politics and government
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/10948/33823 , vital:33086 , Bulk File 7
- Description: 'Think' is a journal related to the Unity Movement. The author is Hosea Jaffe a long-standing NEUM theoretician who went into exile in the 1960s but remained an active member.
- Full Text: false
- Date Issued: 1998-01
- Date: 1998-01
- Subjects: Government, Resistance to -- South Africa , South Africa -- History -- 20th century , South Africa -- Politics and government
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/10948/33823 , vital:33086 , Bulk File 7
- Description: 'Think' is a journal related to the Unity Movement. The author is Hosea Jaffe a long-standing NEUM theoretician who went into exile in the 1960s but remained an active member.
- Full Text: false
- Date Issued: 1998-01