Metallophthalocyanine-based molecular materials as catalysts for electrochemical reactions
- Zagal, José H, Griveau, Sophie J, Silva, Francisco, Nyokong, Tebello, Bedioui, Fethi
- Authors: Zagal, José H , Griveau, Sophie J , Silva, Francisco , Nyokong, Tebello , Bedioui, Fethi
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:7239 , http://hdl.handle.net/10962/d1019718
- Description: Metallophthalocyanines confined on the surface of electrodes are active catalysts for a large variety of electrochemical reactions and electrode surfaces modified by these complexes can be obtained by simple adsorption on graphite and carbon. However, more stable electrodes can be achieved by coating their surfaces with electropolymerized layers of the complexes, that show similar activity than their monomer counterparts. In all cases, fundamental studies carried out with adsorbed layers of these complexes have shown that the redox potential is a very good reactivity index for predicting the catalytic activity of the complexes. Volcano-shaped correlations have been found between the electrocatalytic activity (as log I at constant E) versus the Co(II)/(I) formal potential (E°′) of Co-macrocyclics for the oxidation of several thiols, hydrazine and glucose. For the electroreduction of O2 only linear correlations between the electrocatalytic activity versus the M(III)/M(II) formal potential have been found using Cr, Mn, Fe and Co phthalocyanines but it is likely that these correlations are “incomplete volcano” correlations. The volcano correlations strongly suggest that E°′, the formal potential of the complex needs to be in a rather narrow potential window for achieving maximum activity, probably corresponding to surface coverages of an M-molecule adduct equal to 0.5 and to standard free energies of adsorption of the reacting molecule on the complex active site equal to zero. These results indicate that the catalytic activity of metallophthalocyanines for the oxidation of several molecules can be “tuned” by manipulating the E°′ formal potential, using proper groups on the macrocyclic ligand. This review emphasizes once more that metallophthalocyanines are extremely versatile materials with many applications in electrocatalysis, electroanalysis, just to mention a few, and they provide very good models for testing their catalytic activity for several reactions. Even though the earlier applications of these complexes were focused on providing active materials for electroreduction of O2, for making active cathodes for fuel cells, the main trend in the literature nowadays is to use these complexes for making active electrodes for electrochemical sensors. , Original publication is available at http://dx.doi.org/10.1016/j.ccr.2010.05.001
- Full Text: false
- Date Issued: 2010
- Authors: Zagal, José H , Griveau, Sophie J , Silva, Francisco , Nyokong, Tebello , Bedioui, Fethi
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:7239 , http://hdl.handle.net/10962/d1019718
- Description: Metallophthalocyanines confined on the surface of electrodes are active catalysts for a large variety of electrochemical reactions and electrode surfaces modified by these complexes can be obtained by simple adsorption on graphite and carbon. However, more stable electrodes can be achieved by coating their surfaces with electropolymerized layers of the complexes, that show similar activity than their monomer counterparts. In all cases, fundamental studies carried out with adsorbed layers of these complexes have shown that the redox potential is a very good reactivity index for predicting the catalytic activity of the complexes. Volcano-shaped correlations have been found between the electrocatalytic activity (as log I at constant E) versus the Co(II)/(I) formal potential (E°′) of Co-macrocyclics for the oxidation of several thiols, hydrazine and glucose. For the electroreduction of O2 only linear correlations between the electrocatalytic activity versus the M(III)/M(II) formal potential have been found using Cr, Mn, Fe and Co phthalocyanines but it is likely that these correlations are “incomplete volcano” correlations. The volcano correlations strongly suggest that E°′, the formal potential of the complex needs to be in a rather narrow potential window for achieving maximum activity, probably corresponding to surface coverages of an M-molecule adduct equal to 0.5 and to standard free energies of adsorption of the reacting molecule on the complex active site equal to zero. These results indicate that the catalytic activity of metallophthalocyanines for the oxidation of several molecules can be “tuned” by manipulating the E°′ formal potential, using proper groups on the macrocyclic ligand. This review emphasizes once more that metallophthalocyanines are extremely versatile materials with many applications in electrocatalysis, electroanalysis, just to mention a few, and they provide very good models for testing their catalytic activity for several reactions. Even though the earlier applications of these complexes were focused on providing active materials for electroreduction of O2, for making active cathodes for fuel cells, the main trend in the literature nowadays is to use these complexes for making active electrodes for electrochemical sensors. , Original publication is available at http://dx.doi.org/10.1016/j.ccr.2010.05.001
- Full Text: false
- Date Issued: 2010
The effect of physico-chemical parameters and chemical compounds on the activity of β-d-galactosidase (B-GAL), a marker enzyme for indicator microorganisms in water
- Authors: Wutor, V C , Togo, C A
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6470 , http://hdl.handle.net/10962/d1005800 , https://doi.org/10.1016/j.chemosphere.2007.02.050
- Description: The presence of coliforms in polluted water was determined enzymatically (in situ) by directly monitoring the activity of beta-d-galactosidase (B-GAL) through the hydrolysis of the yellow chromogenic subtrate, chlorophenol red beta-d-galactopyranoside (CPRG), which produced a red chlorophenol red (CPR) product. The objectives of this study were to monitor the effect of compounds commonly found in the environment and used in water treatment on a B-GAL CPRG assay and to investigate the differences between the environmental B-GAL enzyme and the pure commercial enzyme. Environmental B-GAL was optimally active at pH 7.8. Two temperature optima were observed at 35 and 55 degrees C, respectively. B-GAL activity was strongly inhibited by silver and copper ions. While calcium and ferrous ions at lower concentrations (50-100mgl(-1)) increased the enzyme activity, a reduction was observed at higher concentrations (200mgl(-1)). Sodium hypochlorite, normally used in rural areas to disinfect water gradually decreased B-GAL activity at concentrations between 0 and 5600ppm for both the commercial and environmental enzymes. B-GAL from the environment behaved differently from its commercially available counterpart.
- Full Text:
- Date Issued: 2007
- Authors: Wutor, V C , Togo, C A
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6470 , http://hdl.handle.net/10962/d1005800 , https://doi.org/10.1016/j.chemosphere.2007.02.050
- Description: The presence of coliforms in polluted water was determined enzymatically (in situ) by directly monitoring the activity of beta-d-galactosidase (B-GAL) through the hydrolysis of the yellow chromogenic subtrate, chlorophenol red beta-d-galactopyranoside (CPRG), which produced a red chlorophenol red (CPR) product. The objectives of this study were to monitor the effect of compounds commonly found in the environment and used in water treatment on a B-GAL CPRG assay and to investigate the differences between the environmental B-GAL enzyme and the pure commercial enzyme. Environmental B-GAL was optimally active at pH 7.8. Two temperature optima were observed at 35 and 55 degrees C, respectively. B-GAL activity was strongly inhibited by silver and copper ions. While calcium and ferrous ions at lower concentrations (50-100mgl(-1)) increased the enzyme activity, a reduction was observed at higher concentrations (200mgl(-1)). Sodium hypochlorite, normally used in rural areas to disinfect water gradually decreased B-GAL activity at concentrations between 0 and 5600ppm for both the commercial and environmental enzymes. B-GAL from the environment behaved differently from its commercially available counterpart.
- Full Text:
- Date Issued: 2007
Intellectual challenge is as necessary as breathing: an interview with Laurence Wright
- Authors: Wright, Laurence , Pearce, B
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:7059 , http://hdl.handle.net/10962/d1007422
- Description: Professor Laurence Wright is Director of the Institute for the Study of English in Africa at Rhodes University. In 2009, he will have completed 25 years of research, teaching and scholarship at Rhodes University and this interview marks the occasion. A Rhodes Scholar and a Commonwealth Scholar, he studied at the universities of Rhodes, Warwick and Oxford. He is also Honorary Life President of the Shakespeare Society of Southern Africa. He has published widely in literary studies and is the Managing Editor of two academic journals as well as of the poetry magazine New Coin. He currently serves on the Council of the English Academy and is a co-opted member of the English National Language Body. He has taken a broad interest in the role of English in this country, ranging from language policy and teacher education matters, to archival research and the role of the humanities in public life. I thought that it would be worthwhile to interview him as his knowledge of literature is substantial, while his incisive and engaging thoughts on a range of topics are worth hearing. The interview was conducted intermittently by email between July and October, 2008.
- Full Text:
- Date Issued: 2009
- Authors: Wright, Laurence , Pearce, B
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:7059 , http://hdl.handle.net/10962/d1007422
- Description: Professor Laurence Wright is Director of the Institute for the Study of English in Africa at Rhodes University. In 2009, he will have completed 25 years of research, teaching and scholarship at Rhodes University and this interview marks the occasion. A Rhodes Scholar and a Commonwealth Scholar, he studied at the universities of Rhodes, Warwick and Oxford. He is also Honorary Life President of the Shakespeare Society of Southern Africa. He has published widely in literary studies and is the Managing Editor of two academic journals as well as of the poetry magazine New Coin. He currently serves on the Council of the English Academy and is a co-opted member of the English National Language Body. He has taken a broad interest in the role of English in this country, ranging from language policy and teacher education matters, to archival research and the role of the humanities in public life. I thought that it would be worthwhile to interview him as his knowledge of literature is substantial, while his incisive and engaging thoughts on a range of topics are worth hearing. The interview was conducted intermittently by email between July and October, 2008.
- Full Text:
- Date Issued: 2009
Science after a century at Rhodes University
- Authors: Woods, D R
- Date: 2004
- Language: English
- Type: Article , text
- Identifier: vital:7123 , http://hdl.handle.net/10962/d1006584
- Description: Rhodes Centenary issue , The small University of Rhodes (6142 students), in the rural city of Grahamstown, was established in 1904 as a result of a £50 000 grant from the Rhodes Trust in Oxford. It grew out of St Andrew’s College, which provided the first four professors and 41 students. The first paper from Rhodes in the South African Journal of Science (then called the Report of the South African Association for the Advancement of Science) was by Selmar Schonland, one of the university’s founding fathers. Entitled: ‘Biological and ethnological observations on a trip to the N.E. Kalahari’, it appeared in 1904. The following pages provide a glimpse into the growth and achievements of various departments in the faculties of Science and Pharmacy and associated institutes a century after the university was born.
- Full Text:
- Date Issued: 2004
- Authors: Woods, D R
- Date: 2004
- Language: English
- Type: Article , text
- Identifier: vital:7123 , http://hdl.handle.net/10962/d1006584
- Description: Rhodes Centenary issue , The small University of Rhodes (6142 students), in the rural city of Grahamstown, was established in 1904 as a result of a £50 000 grant from the Rhodes Trust in Oxford. It grew out of St Andrew’s College, which provided the first four professors and 41 students. The first paper from Rhodes in the South African Journal of Science (then called the Report of the South African Association for the Advancement of Science) was by Selmar Schonland, one of the university’s founding fathers. Entitled: ‘Biological and ethnological observations on a trip to the N.E. Kalahari’, it appeared in 1904. The following pages provide a glimpse into the growth and achievements of various departments in the faculties of Science and Pharmacy and associated institutes a century after the university was born.
- Full Text:
- Date Issued: 2004
Bioavailability and activity of 0.1% amcinonide preparations: comparison with proprietary topical corticosteroid formulations of differing potencies
- Authors: Woodford, R , Haigh, John M
- Date: 1979
- Language: English
- Type: text , Article
- Identifier: vital:6447 , http://hdl.handle.net/10962/d1006634
- Description: The activity of a 0.1% amcinonide cream was compared with those of selected proprietary topical corticosteroid formulations of potencies differing according to the United Kingdom (U.K.) MIMS classification (very potent, potent and moderately potent) using a standard six hour vasoconstrictor assay with multiple reading times. Statistical analysis indicated that 0.1% amcinonide cream feU within the category of a very potent preparation. Three 0.1% amcinonide formulations (cream, combination cream and combination ointment, the last two containing anti-infective agents) were equipotent in the skin-blanching test.
- Full Text:
- Date Issued: 1979
- Authors: Woodford, R , Haigh, John M
- Date: 1979
- Language: English
- Type: text , Article
- Identifier: vital:6447 , http://hdl.handle.net/10962/d1006634
- Description: The activity of a 0.1% amcinonide cream was compared with those of selected proprietary topical corticosteroid formulations of potencies differing according to the United Kingdom (U.K.) MIMS classification (very potent, potent and moderately potent) using a standard six hour vasoconstrictor assay with multiple reading times. Statistical analysis indicated that 0.1% amcinonide cream feU within the category of a very potent preparation. Three 0.1% amcinonide formulations (cream, combination cream and combination ointment, the last two containing anti-infective agents) were equipotent in the skin-blanching test.
- Full Text:
- Date Issued: 1979
A history of southern African research relevant to forensic entomology
- Williams, K A, Villet, Martin H
- Authors: Williams, K A , Villet, Martin H
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6909 , http://hdl.handle.net/10962/d1011862
- Description: Entomological forensic evidence has been used in southern Africa for decades but explicitly forensic research began in southern Africa only 26 years ago. Although applicable local research has accumulated since 1921, it is scattered in a diverse literature or unpublished. Some overseas research has also touched on local species. This review uses a historical approach to synthesize the southern African literature and to illustrate the cross-disciplinary, opportunistic nature of forensic entomology. Distinct phases of research focused on agriculture (1921-1950), medicine (1952- 1965), ecology (1968-1990) and forensics (1980-2005), but systematics spanned the entire period and tended to be ad hoc. Few scientists were involved, situated at geographically distant locations and with widely disparate research interests. The review concludes with an overview of southern African entomologists who have been involved in medico-legal investigations, and a critical evaluation of the past and future of the discipline locally.
- Full Text:
- Date Issued: 2006
- Authors: Williams, K A , Villet, Martin H
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6909 , http://hdl.handle.net/10962/d1011862
- Description: Entomological forensic evidence has been used in southern Africa for decades but explicitly forensic research began in southern Africa only 26 years ago. Although applicable local research has accumulated since 1921, it is scattered in a diverse literature or unpublished. Some overseas research has also touched on local species. This review uses a historical approach to synthesize the southern African literature and to illustrate the cross-disciplinary, opportunistic nature of forensic entomology. Distinct phases of research focused on agriculture (1921-1950), medicine (1952- 1965), ecology (1968-1990) and forensics (1980-2005), but systematics spanned the entire period and tended to be ad hoc. Few scientists were involved, situated at geographically distant locations and with widely disparate research interests. The review concludes with an overview of southern African entomologists who have been involved in medico-legal investigations, and a critical evaluation of the past and future of the discipline locally.
- Full Text:
- Date Issued: 2006
Recruitment behaviour in the ponerine ant, Plectroctena mandibularis F. Smith (Hymenoptera: Formicidae)
- Wilkins, K J, Harman, K, Villet, Martin H
- Authors: Wilkins, K J , Harman, K , Villet, Martin H
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6887 , http://hdl.handle.net/10962/d1011647
- Description: Although workers of Plectroctena mandibularis laid trails with their stings while foraging, the trails appeared to be for individual orientation, because they never recruited nestmates to prey. However, both workers and queens laid trails when recruiting nestmates of either caste to new nest sites. During trail-laying, fluted hairs on the posterior edge of tergite VI were dragged along the ground, presumably applying a pheromone to the substrate. Anatomical and behavioural evidence suggests that pygidial gland secretions moved from the intersegmental pygidial gland between tergites VI and VII into a fingerprint-like, lamellar cuticular reservoir on the pygidium, and from there via the hairs to the substrate. These results suggest that recruitment may be crucial to moving nests but of value only to certain types of foraging, and that recruitment might even have originated in the Formicidae in the context of colony relocation, and then secondarily evolved to assist foraging.
- Full Text:
- Date Issued: 2006
- Authors: Wilkins, K J , Harman, K , Villet, Martin H
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6887 , http://hdl.handle.net/10962/d1011647
- Description: Although workers of Plectroctena mandibularis laid trails with their stings while foraging, the trails appeared to be for individual orientation, because they never recruited nestmates to prey. However, both workers and queens laid trails when recruiting nestmates of either caste to new nest sites. During trail-laying, fluted hairs on the posterior edge of tergite VI were dragged along the ground, presumably applying a pheromone to the substrate. Anatomical and behavioural evidence suggests that pygidial gland secretions moved from the intersegmental pygidial gland between tergites VI and VII into a fingerprint-like, lamellar cuticular reservoir on the pygidium, and from there via the hairs to the substrate. These results suggest that recruitment may be crucial to moving nests but of value only to certain types of foraging, and that recruitment might even have originated in the Formicidae in the context of colony relocation, and then secondarily evolved to assist foraging.
- Full Text:
- Date Issued: 2006
The Benthic invertebrate community of a Southern Cape estuary : structure and possible food sources
- Authors: Whitfield, A K
- Date: 1989
- Language: English
- Type: text , Article
- Identifier: vital:7154 , http://hdl.handle.net/10962/d1011871
- Description: Cluster analysis of invertebrate communities in the Swartvlei estuary revealed that vegetated (Zostera capensis) sites were distinct from unvegetated ones. `Indicator species' for the eelgrass group included Melita zeylinaca, Loripes clausus, Natica tecta and Palaemon pacificus, whereas those for the bare sand community were Urothoe pulchella, Callianassa kraussi, Iphinoe truncata and Pontogeloides latipes. Infaunal bivalves comprised >60 % of the invertebrate biomass at Zostera sites but <5 % at bare sand sites. Conversely the infaunal anomuran C. kraussi dominated the sandy sites (>80 %) and was a minor component (<5 %) at eelgrass sites. The supratidal invertebrate community was dominated by Orchestia spp. which live and feed on wrack detritus. Litterbag experiments revealed that degradation of Zostera leaf wrack was rapid during the first thirty days after deposition but slow between 40 and 140 days. Laboratory experiments indicated that Orchestia consumption of wrack material could not account for the rapid weight loss recorded in the natural environment. Preliminary diet analyses of intertidal and infratidal zoobenthos revealed that most invertebrate species feed on detritus and associated microorganisms. Filamentous algae and diatoms dominated the gut contents of only three out of 18 macrobenthic species, and living Zostera was not an important food item for any invertebrate examined.
- Full Text: false
- Date Issued: 1989
- Authors: Whitfield, A K
- Date: 1989
- Language: English
- Type: text , Article
- Identifier: vital:7154 , http://hdl.handle.net/10962/d1011871
- Description: Cluster analysis of invertebrate communities in the Swartvlei estuary revealed that vegetated (Zostera capensis) sites were distinct from unvegetated ones. `Indicator species' for the eelgrass group included Melita zeylinaca, Loripes clausus, Natica tecta and Palaemon pacificus, whereas those for the bare sand community were Urothoe pulchella, Callianassa kraussi, Iphinoe truncata and Pontogeloides latipes. Infaunal bivalves comprised >60 % of the invertebrate biomass at Zostera sites but <5 % at bare sand sites. Conversely the infaunal anomuran C. kraussi dominated the sandy sites (>80 %) and was a minor component (<5 %) at eelgrass sites. The supratidal invertebrate community was dominated by Orchestia spp. which live and feed on wrack detritus. Litterbag experiments revealed that degradation of Zostera leaf wrack was rapid during the first thirty days after deposition but slow between 40 and 140 days. Laboratory experiments indicated that Orchestia consumption of wrack material could not account for the rapid weight loss recorded in the natural environment. Preliminary diet analyses of intertidal and infratidal zoobenthos revealed that most invertebrate species feed on detritus and associated microorganisms. Filamentous algae and diatoms dominated the gut contents of only three out of 18 macrobenthic species, and living Zostera was not an important food item for any invertebrate examined.
- Full Text: false
- Date Issued: 1989
A review of estuarine ichthyology in South Africa over the past 50 years
- Authors: Whitfield, A K
- Date: 1996
- Language: English
- Type: text , Article
- Identifier: vital:7155 , http://hdl.handle.net/10962/d1011873
- Description: Progress in South African estuarine ichthyology between 1946 and 1995 is reviewed. The early estuary surveys of the 1950s and 1960s resulted in the compilation of species lists for individual systems, but contained very little biological or ecological information on fishes. These surveys were superseded by both autecological and synecological studies in the 1970s and 1980s, which yielded descriptive and process-orientated information on a wide variety of species. Estuarine research during the 1990s has focused increasingly at the community level, with several review papers on the life-history styles of groups of estuarine-associated fishes being published. The last decade has also seen the departure of a number of senior estuarine ichthyologists from the field. This decline in available expertise has coincided with increased demand for ichthyological information to be used in decision support systems for the wise management and conservation of estuaries. It is suggested that these demands be seen as a challenge, with studies being directed towards providing the type of information needed for the maintenance of vital ecological processes within these systems.
- Full Text: false
- Date Issued: 1996
- Authors: Whitfield, A K
- Date: 1996
- Language: English
- Type: text , Article
- Identifier: vital:7155 , http://hdl.handle.net/10962/d1011873
- Description: Progress in South African estuarine ichthyology between 1946 and 1995 is reviewed. The early estuary surveys of the 1950s and 1960s resulted in the compilation of species lists for individual systems, but contained very little biological or ecological information on fishes. These surveys were superseded by both autecological and synecological studies in the 1970s and 1980s, which yielded descriptive and process-orientated information on a wide variety of species. Estuarine research during the 1990s has focused increasingly at the community level, with several review papers on the life-history styles of groups of estuarine-associated fishes being published. The last decade has also seen the departure of a number of senior estuarine ichthyologists from the field. This decline in available expertise has coincided with increased demand for ichthyological information to be used in decision support systems for the wise management and conservation of estuaries. It is suggested that these demands be seen as a challenge, with studies being directed towards providing the type of information needed for the maintenance of vital ecological processes within these systems.
- Full Text: false
- Date Issued: 1996
Recent African derivation of Chrysomya putoria from C. chloropyga and mitochondrial DNA paraphyly of cytochrome oxidase subunit one in blowflies of forensic importance
- Wells, J D, Lunt, N, Villet, Martin H
- Authors: Wells, J D , Lunt, N , Villet, Martin H
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6888 , http://hdl.handle.net/10962/d1011648
- Description: Chrysomya chloropyga (Wiedemann) and C. putoria (Wiedemann) (Diptera: Calliphoridae) are closely related Afrotropical blowflies that breed in carrion and latrines, reaching high density in association with humans and spreading to other continents. In some cases of human death, Chyrsomya specimens provide forensic clues. Because the immature stages of such flies are often difficult to identify taxonomically, it is useful to develop DNA-based tests for specimen identification. Therefore we attempted to distinguish between C. chloropyga and C. putoria using mitochondrial DNA (mtDNA) sequence data from a 593-bp region of the gene for cytochrome oxidase subunit one (COI). Twelve specimens from each species yielded a total of five haplotypes, none being unique to C. putoria. Therefore it was not possible to distinguish between the two species using this locus. Maximum parsimony analysis indicated paraphyletic C. chloropyga mtDNA with C. putoria nested therein. Based on these and previously published data, we infer that C. putoria diverged very recently from C. chloropyga.
- Full Text:
- Date Issued: 2004
- Authors: Wells, J D , Lunt, N , Villet, Martin H
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6888 , http://hdl.handle.net/10962/d1011648
- Description: Chrysomya chloropyga (Wiedemann) and C. putoria (Wiedemann) (Diptera: Calliphoridae) are closely related Afrotropical blowflies that breed in carrion and latrines, reaching high density in association with humans and spreading to other continents. In some cases of human death, Chyrsomya specimens provide forensic clues. Because the immature stages of such flies are often difficult to identify taxonomically, it is useful to develop DNA-based tests for specimen identification. Therefore we attempted to distinguish between C. chloropyga and C. putoria using mitochondrial DNA (mtDNA) sequence data from a 593-bp region of the gene for cytochrome oxidase subunit one (COI). Twelve specimens from each species yielded a total of five haplotypes, none being unique to C. putoria. Therefore it was not possible to distinguish between the two species using this locus. Maximum parsimony analysis indicated paraphyletic C. chloropyga mtDNA with C. putoria nested therein. Based on these and previously published data, we infer that C. putoria diverged very recently from C. chloropyga.
- Full Text:
- Date Issued: 2004
Olive Schreiner at 150: some thoughts on re-editing Cronwright's The Reinterment on Buffelskop
- Walters, Paul S, Fogg, W Jeremy M
- Authors: Walters, Paul S , Fogg, W Jeremy M
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6124 , http://hdl.handle.net/10962/d1004708
- Description: [From the introduction]: The original edition of Cronwright’s The Reinterment on Buffelskop (1983) was produced by Guy Butler and Nick Visser to commemorate the centenary of the 1883 publication of The Story of an African Farm. The Butler-Visser text was a photographic reproduction of a typed carbon copy of the first part of Cronwright’s extant diaries plus a special diary he had kept covering in detail the events of the actual reinterment. (The originals are now at the National English Literary Museum [NELM].) Butler included a comprehensive and illuminating introduction to these texts, as well as – under separate soft cover – a set of “Provisional Notes” which draw deeply on his own and his family’s accumulated knowledge of Cradock, its environs and inhabitants. In addition, Butler and Visser included two passages excised by Cronwright from the typescript of his Life of Olive Schreiner: a word picture of Charles Heathcote, and the longer account of “The Nienaber Incident” – pages which deal with the execution of three innocent men at De Aar on 19 March 1901, and Cronwright’s subsequent attempts at legal reparation for them and their families. The substantive text of the Butler-Visser edition is often difficult to read because of the method of reproduction; moreover, because it also reproduces Cronwright’s emendations (in ink) of the typescript, it is frankly uninviting. Thus, when the NELM Council proposed a publication commemorating the 150th anniversary of Olive Schreiner’s birth on 24 March 1855, it seemed appropriate that a second attempt be made to give students of Olive Schreiner’s works easier access to Cronwright’s detailed account of this “bizarre, romantic” episode. Furthermore, from the perspective of text history, the typescript of the Reinterment antedates both Cronwright’s Life and The Letters of Olive Schreiner. Parts of it are clearly Cronwright’s preliminary ‘notes towards’ his Life, and, as Butler hypothesizes, the whole of the Reinterment might have been intended as a separate (and earlier) publication. Finally, the sarcophagus on Buffelskop is one of South Africa’s more noteworthy literary shrines: while the idea of re-editing an account of Olive Schreiner’s reinterment might be thought to be a futile exercise in intellectual recycling, our intention is that both husband and wife should live again through a rediscovery of the thoughts and feelings that led them to this dramatic final resting-place.
- Full Text:
- Date Issued: 2006
- Authors: Walters, Paul S , Fogg, W Jeremy M
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6124 , http://hdl.handle.net/10962/d1004708
- Description: [From the introduction]: The original edition of Cronwright’s The Reinterment on Buffelskop (1983) was produced by Guy Butler and Nick Visser to commemorate the centenary of the 1883 publication of The Story of an African Farm. The Butler-Visser text was a photographic reproduction of a typed carbon copy of the first part of Cronwright’s extant diaries plus a special diary he had kept covering in detail the events of the actual reinterment. (The originals are now at the National English Literary Museum [NELM].) Butler included a comprehensive and illuminating introduction to these texts, as well as – under separate soft cover – a set of “Provisional Notes” which draw deeply on his own and his family’s accumulated knowledge of Cradock, its environs and inhabitants. In addition, Butler and Visser included two passages excised by Cronwright from the typescript of his Life of Olive Schreiner: a word picture of Charles Heathcote, and the longer account of “The Nienaber Incident” – pages which deal with the execution of three innocent men at De Aar on 19 March 1901, and Cronwright’s subsequent attempts at legal reparation for them and their families. The substantive text of the Butler-Visser edition is often difficult to read because of the method of reproduction; moreover, because it also reproduces Cronwright’s emendations (in ink) of the typescript, it is frankly uninviting. Thus, when the NELM Council proposed a publication commemorating the 150th anniversary of Olive Schreiner’s birth on 24 March 1855, it seemed appropriate that a second attempt be made to give students of Olive Schreiner’s works easier access to Cronwright’s detailed account of this “bizarre, romantic” episode. Furthermore, from the perspective of text history, the typescript of the Reinterment antedates both Cronwright’s Life and The Letters of Olive Schreiner. Parts of it are clearly Cronwright’s preliminary ‘notes towards’ his Life, and, as Butler hypothesizes, the whole of the Reinterment might have been intended as a separate (and earlier) publication. Finally, the sarcophagus on Buffelskop is one of South Africa’s more noteworthy literary shrines: while the idea of re-editing an account of Olive Schreiner’s reinterment might be thought to be a futile exercise in intellectual recycling, our intention is that both husband and wife should live again through a rediscovery of the thoughts and feelings that led them to this dramatic final resting-place.
- Full Text:
- Date Issued: 2006
Olive Schreiner in Rhodesia: an episode in a biography
- Walters, Paul S, Fogg, W Jeremy M
- Authors: Walters, Paul S , Fogg, W Jeremy M
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6123 , http://hdl.handle.net/10962/d1004707
- Description: Readers of biographies of Olive Schreiner - except for the pioneering work of Vera Buchanan-Gould (see 1948, 198-99) - could be forgiven for doubting whether Olive Schreiner ever was in Rhodesia. Although her husband's edition of her Letters includes three which cover this journey (Cronwright-Schreiner 1924a), he makes no mention of it in his Life (1924), and it is not touched on either in First and Scott (1980) or in Stanley's impressive biographical chapter (2002). Arguably, it does nothing to alter the by now well-established outlines of Olive Schreiner's life; yet, as we shall see, the visit itself might have meant the premature end of that life. Moreover, it documents Schreiner's visit to two sites of immense importance to her : the 'Hanging Tree' in Bulawayo which features in the (deliberately shocking) photographic frontispiece to the first edition of Trooper Peter Halket of Mashonaland (1897), and, secondly, Cecil Rhodes's grave in the Matopos. In just over a decade (13 Aug. 1921), she too would lie in her chosen mountaintop tomb.
- Full Text:
- Date Issued: 2007
- Authors: Walters, Paul S , Fogg, W Jeremy M
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6123 , http://hdl.handle.net/10962/d1004707
- Description: Readers of biographies of Olive Schreiner - except for the pioneering work of Vera Buchanan-Gould (see 1948, 198-99) - could be forgiven for doubting whether Olive Schreiner ever was in Rhodesia. Although her husband's edition of her Letters includes three which cover this journey (Cronwright-Schreiner 1924a), he makes no mention of it in his Life (1924), and it is not touched on either in First and Scott (1980) or in Stanley's impressive biographical chapter (2002). Arguably, it does nothing to alter the by now well-established outlines of Olive Schreiner's life; yet, as we shall see, the visit itself might have meant the premature end of that life. Moreover, it documents Schreiner's visit to two sites of immense importance to her : the 'Hanging Tree' in Bulawayo which features in the (deliberately shocking) photographic frontispiece to the first edition of Trooper Peter Halket of Mashonaland (1897), and, secondly, Cecil Rhodes's grave in the Matopos. In just over a decade (13 Aug. 1921), she too would lie in her chosen mountaintop tomb.
- Full Text:
- Date Issued: 2007
Sensitive high-performance liquid chromatographic determination of cyclizine and its demethylated metabolite, norcyclizine, in biological fluids using coulometric detection
- Walker, Roderick B, Kanfer, Isadore
- Authors: Walker, Roderick B , Kanfer, Isadore
- Date: 1995
- Language: English
- Type: text , Article
- Identifier: vital:6452 , http://hdl.handle.net/10962/d1006640 , http://dx.doi.org/10.1016/0378-4347(95)00202-T
- Description: An accurate, sensitive, selective and reproducible high-performance liquid chromatographic method with coulometric detection for the determination of cyclizine and its inactive demethylated metabolite, norcyclizine, in biological fluids has been developed. The drugs were separated using a custom packed reversed-phase C18 analytical column and phosphate buffer (0.05 M, pH 3)-acetonitrile (7:3) as mobile phase. The dual electrode coulometric detector was operated in the "oxidative-screen" mode with the upstream electrode (detector 1) set at 0.55 V and the downstream electrode (detector 2) set at 0.90 V. Serum and urine samples were prepared for analysis by solid-phase extraction, followed by a simple phase-separation step. The limit of quantitation was 1 ng/ml for both cyclizine and norcyclizine in serum and urine.
- Full Text:
- Date Issued: 1995
- Authors: Walker, Roderick B , Kanfer, Isadore
- Date: 1995
- Language: English
- Type: text , Article
- Identifier: vital:6452 , http://hdl.handle.net/10962/d1006640 , http://dx.doi.org/10.1016/0378-4347(95)00202-T
- Description: An accurate, sensitive, selective and reproducible high-performance liquid chromatographic method with coulometric detection for the determination of cyclizine and its inactive demethylated metabolite, norcyclizine, in biological fluids has been developed. The drugs were separated using a custom packed reversed-phase C18 analytical column and phosphate buffer (0.05 M, pH 3)-acetonitrile (7:3) as mobile phase. The dual electrode coulometric detector was operated in the "oxidative-screen" mode with the upstream electrode (detector 1) set at 0.55 V and the downstream electrode (detector 2) set at 0.90 V. Serum and urine samples were prepared for analysis by solid-phase extraction, followed by a simple phase-separation step. The limit of quantitation was 1 ng/ml for both cyclizine and norcyclizine in serum and urine.
- Full Text:
- Date Issued: 1995
Role of percutaneous penetration enhancers
- Walker, Roderick B, Smith, Eric W
- Authors: Walker, Roderick B , Smith, Eric W
- Date: 1996
- Language: English
- Type: text , Article
- Identifier: vital:6446 , http://hdl.handle.net/10962/d1006633
- Description: It is clear that scientists are now only beginning to comprehend the complexity of transdermal drug delivery. Elucidation of the biochemical composition and functioning of the intrinsic diffusional barrier of the stratum corneum has prompted investigation of chemical and physical means of enhancing the percutaneous penetration of poorly absorbed drugs. Chemical enhancers that aid absorption of co-administered moieties are currently believed to improve solubility within the stratum corneum or increase lipid fluidity of the intracellular bilayers. Alternatively,the use of ionto- or phonophoresis may facilitate the absorption of some drug molecules by physical alteration of the barrier. The role of penetration enhancer inclusion in topical formulations has been well documented and will undoubtedly, in the future, permit the delivery of broader classes of drugs through the stratum corneum.
- Full Text:
- Date Issued: 1996
- Authors: Walker, Roderick B , Smith, Eric W
- Date: 1996
- Language: English
- Type: text , Article
- Identifier: vital:6446 , http://hdl.handle.net/10962/d1006633
- Description: It is clear that scientists are now only beginning to comprehend the complexity of transdermal drug delivery. Elucidation of the biochemical composition and functioning of the intrinsic diffusional barrier of the stratum corneum has prompted investigation of chemical and physical means of enhancing the percutaneous penetration of poorly absorbed drugs. Chemical enhancers that aid absorption of co-administered moieties are currently believed to improve solubility within the stratum corneum or increase lipid fluidity of the intracellular bilayers. Alternatively,the use of ionto- or phonophoresis may facilitate the absorption of some drug molecules by physical alteration of the barrier. The role of penetration enhancer inclusion in topical formulations has been well documented and will undoubtedly, in the future, permit the delivery of broader classes of drugs through the stratum corneum.
- Full Text:
- Date Issued: 1996
Recovery of the critically endangered river pipefish, Syngnathus watermeyeri, in the Kariega Estuary, Eastern Cape province
- Vorwerk, Paul D, Froneman, P William, Paterson, Angus W
- Authors: Vorwerk, Paul D , Froneman, P William , Paterson, Angus W
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6965 , http://hdl.handle.net/10962/d1012028
- Description: An intensive ichthyofaunal survey in the permanently open Kariega Estuary along the Eastern Cape coast has identified a breeding population of the critically endangered river pipefish, Syngnathus watermeyeri, within the middle and upper reaches of the system. This is the first recorded capture of this species in the estuary for over four decades. We suggest that the presence of S. watermeyeri is the result of the heavy rainfall within the region, which contributed to the establishment of optimum habitat requirements (mesohaline conditions and increased food availability) of the pipefish.
- Full Text:
- Date Issued: 2007
- Authors: Vorwerk, Paul D , Froneman, P William , Paterson, Angus W
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6965 , http://hdl.handle.net/10962/d1012028
- Description: An intensive ichthyofaunal survey in the permanently open Kariega Estuary along the Eastern Cape coast has identified a breeding population of the critically endangered river pipefish, Syngnathus watermeyeri, within the middle and upper reaches of the system. This is the first recorded capture of this species in the estuary for over four decades. We suggest that the presence of S. watermeyeri is the result of the heavy rainfall within the region, which contributed to the establishment of optimum habitat requirements (mesohaline conditions and increased food availability) of the pipefish.
- Full Text:
- Date Issued: 2007
Biological responses to a resumption in river flow in a freshwater-deprived, permanently open Southern African estuary
- Vorwerk, Paul D, Froneman, P William, Paterson, Angus W, Strydom, Nadine A, Whitfield, A K
- Authors: Vorwerk, Paul D , Froneman, P William , Paterson, Angus W , Strydom, Nadine A , Whitfield, A K
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6886 , http://hdl.handle.net/10962/d1011645
- Description: The Kariega Estuary is a freshwater-deprived system due to numerous impoundments in the catchment. This system has had little or no horizontal salinity gradient over the last 15 years, with hypersaline conditions sometimes predominating in the upper reaches. Following high rainfall events in the catchment during the spring of 2006, including a flood event (approximate 1:10 year) in August 2006, a series of riverine pulses entered the estuary and a horizontal salinity gradient was established. This study examined the influence of this freshwater pulse on four components of the biota within the estuary, namely the zooplankton, and larval, littoral and demersal fishes. The study demonstrated that in three of these components elevated densities were recorded following the riverine input, with only the littoral fishes retaining an almost constant density. In addition, changes in the relative contributions of the estuarine utilisation classes for all three fish groups examined indicated that freshwater input into these systems positively influences the abundances. This has significant implications for water managers as it demonstrates the importance of an Ecological Reserve (defined as ‘the water required to protect the aquatic ecosystems of the water resource’) for this system.
- Full Text:
- Date Issued: 2008
- Authors: Vorwerk, Paul D , Froneman, P William , Paterson, Angus W , Strydom, Nadine A , Whitfield, A K
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6886 , http://hdl.handle.net/10962/d1011645
- Description: The Kariega Estuary is a freshwater-deprived system due to numerous impoundments in the catchment. This system has had little or no horizontal salinity gradient over the last 15 years, with hypersaline conditions sometimes predominating in the upper reaches. Following high rainfall events in the catchment during the spring of 2006, including a flood event (approximate 1:10 year) in August 2006, a series of riverine pulses entered the estuary and a horizontal salinity gradient was established. This study examined the influence of this freshwater pulse on four components of the biota within the estuary, namely the zooplankton, and larval, littoral and demersal fishes. The study demonstrated that in three of these components elevated densities were recorded following the riverine input, with only the littoral fishes retaining an almost constant density. In addition, changes in the relative contributions of the estuarine utilisation classes for all three fish groups examined indicated that freshwater input into these systems positively influences the abundances. This has significant implications for water managers as it demonstrates the importance of an Ecological Reserve (defined as ‘the water required to protect the aquatic ecosystems of the water resource’) for this system.
- Full Text:
- Date Issued: 2008
Bread and honour: white working class women and Afrikaner Nationalism in the 1930s
- Authors: Vincent, Louise
- Date: 2000
- Language: English
- Type: text , Article
- Identifier: vital:6205 , http://hdl.handle.net/10962/d1008575
- Description: Women have occupied a central place in the ideological formulations of nationalist movements. In particular, the figure of woman as mother recurs throughout the history of nationalist political mobilizations. In Afrikaner nationalism, this symbolic female identity takes the form of the volksmoeder (mother of the nation) icon, commonly assumed to describe a highly circumscribed set of women's social roles, created for women by men. The academic orthodoxy holds that middle-class Afrikaner women submitted to the volksmoeder ideology early on in the development of Afrikaner nationalism but that the working class Afrikaner women of the Garment Workers' Union (GWU) represented an enclave of resistance to dominant definitions of ethnic identity. They chose instead to ally themselves with militant, class-conscious trade unionism. This paper argues that Afrikaner women of different classes helped to shape the contours of the volksmoeder icon. Whilst middle class Afrikaner women questioned the idea that their social contribution should remain restricted to narrow familial and charitable concerns, prominent working class women laid claim to their own entitlement to the volksmoeder heritage. In doing so, the latter contributed to the popularization and reinterpretation of an ideology that was at this time seeking a wider audience. The paper argues that the incorporation of Afrikaner women into the socialist milieu of the GWU did not result in these women simply discarding the ethnic components of their identity. Rather their self-awareness as Afrikaner women with a recent rural past was grafted onto their new experience as urban factory workers. The way in which leading working class Afrikaner women articulated this potent combination of 'derived' and 'inherent' ideology cannot be excluded from the complex process whereby Afrikaner nationalism achieved success as a movement appealing to its imagined community across boundaries of class and gender.
- Full Text:
- Date Issued: 2000
- Authors: Vincent, Louise
- Date: 2000
- Language: English
- Type: text , Article
- Identifier: vital:6205 , http://hdl.handle.net/10962/d1008575
- Description: Women have occupied a central place in the ideological formulations of nationalist movements. In particular, the figure of woman as mother recurs throughout the history of nationalist political mobilizations. In Afrikaner nationalism, this symbolic female identity takes the form of the volksmoeder (mother of the nation) icon, commonly assumed to describe a highly circumscribed set of women's social roles, created for women by men. The academic orthodoxy holds that middle-class Afrikaner women submitted to the volksmoeder ideology early on in the development of Afrikaner nationalism but that the working class Afrikaner women of the Garment Workers' Union (GWU) represented an enclave of resistance to dominant definitions of ethnic identity. They chose instead to ally themselves with militant, class-conscious trade unionism. This paper argues that Afrikaner women of different classes helped to shape the contours of the volksmoeder icon. Whilst middle class Afrikaner women questioned the idea that their social contribution should remain restricted to narrow familial and charitable concerns, prominent working class women laid claim to their own entitlement to the volksmoeder heritage. In doing so, the latter contributed to the popularization and reinterpretation of an ideology that was at this time seeking a wider audience. The paper argues that the incorporation of Afrikaner women into the socialist milieu of the GWU did not result in these women simply discarding the ethnic components of their identity. Rather their self-awareness as Afrikaner women with a recent rural past was grafted onto their new experience as urban factory workers. The way in which leading working class Afrikaner women articulated this potent combination of 'derived' and 'inherent' ideology cannot be excluded from the complex process whereby Afrikaner nationalism achieved success as a movement appealing to its imagined community across boundaries of class and gender.
- Full Text:
- Date Issued: 2000
Systematic status of Plectroctena mandibularis Smith and P. conjugata Santschi (Hymenoptera: Formicidae: Ponerini)
- Villet, Martin H, McKitterick, L, Robertson, H G
- Authors: Villet, Martin H , McKitterick, L , Robertson, H G
- Date: 1999
- Language: English
- Type: text , Article
- Identifier: vital:6893 , http://hdl.handle.net/10962/d1011653
- Description: Plectroctena mandibularis Smith is the type species of Plectroctena F. Smith. Because there has been some doubt about its distinctness from P. conjugata, several techniques were used to assess the systematic status of the two species. Most crucially, several colony series contained workers of both phenotypes, and where these series included queens or males, the distinguishing feature of these specimens was not consistently related to those of the workers. Queens, males and workers did not manifest qualitative differences between the taxa, and morphological variation was continuous between the two. The putative morphological basis (funicular index) for distinguishing workers of the taxa arose from allometric variation. Putatively diagnostic colour variation in males was related to latitude, but no simple pattern of morphological variation could be correlated with geographical distribution. Plectroctena conjugata is therefore considered a junior synonym of P. mandibularis.
- Full Text:
- Date Issued: 1999
- Authors: Villet, Martin H , McKitterick, L , Robertson, H G
- Date: 1999
- Language: English
- Type: text , Article
- Identifier: vital:6893 , http://hdl.handle.net/10962/d1011653
- Description: Plectroctena mandibularis Smith is the type species of Plectroctena F. Smith. Because there has been some doubt about its distinctness from P. conjugata, several techniques were used to assess the systematic status of the two species. Most crucially, several colony series contained workers of both phenotypes, and where these series included queens or males, the distinguishing feature of these specimens was not consistently related to those of the workers. Queens, males and workers did not manifest qualitative differences between the taxa, and morphological variation was continuous between the two. The putative morphological basis (funicular index) for distinguishing workers of the taxa arose from allometric variation. Putatively diagnostic colour variation in males was related to latitude, but no simple pattern of morphological variation could be correlated with geographical distribution. Plectroctena conjugata is therefore considered a junior synonym of P. mandibularis.
- Full Text:
- Date Issued: 1999
Endothermy and chorusing behaviour in the African platypleurine cicada Pycna semiclara (Germar, 1834) (Hemiptera: Cicadidae)
- Villet, Martin H, Sanborn, Allen F, Phillips, P K
- Authors: Villet, Martin H , Sanborn, Allen F , Phillips, P K
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6892 , http://hdl.handle.net/10962/d1011652 , http://dx.doi.org/10.1139/z03-119
- Description: Cicadas use acoustic signals to find mates and therefore offer a phylogenetically independent opportunity to test the generality of ideas about acoustic communication that were developed from studies of other animals. Pycna semiclara (Germar, 1834) (Hemiptera: Cicadidae) is a forest-dwelling platypleurine cicada that uses its calling song to form choruses and attract mates. Additionally, P. semiclara produces an encounter call that is involved in courtship and also in spacing males within choruses. Males generally call from exposed trunks and branches within the understory but clear of the undergrowth and fight with other males that call within about 50 cm of them. Choruses sing sporadically throughout the day but focus most of their calling activity into half-hour bouts at dawn and dusk. Body size and ambient temperature had no significant effect on spectral or temporal characteristics of the calling song. Body temperature measurements indicate that P. semiclara thermoregulates endothermically, with a body temperature of more than 22 °C above ambient temperature being measured during calling activity at dusk. Such endothermy provides an advantage to the cicadas by allowing them to call during crepuscular hours when atmospheric conditions are most optimal for acoustic communication and predation risks are minimal. Coincidentally, endogenously regulating body temperature allows the temporal characteristics of the call to be unaffected by ambient temperature changes.
- Full Text:
- Date Issued: 2003
- Authors: Villet, Martin H , Sanborn, Allen F , Phillips, P K
- Date: 2003
- Language: English
- Type: text , Article
- Identifier: vital:6892 , http://hdl.handle.net/10962/d1011652 , http://dx.doi.org/10.1139/z03-119
- Description: Cicadas use acoustic signals to find mates and therefore offer a phylogenetically independent opportunity to test the generality of ideas about acoustic communication that were developed from studies of other animals. Pycna semiclara (Germar, 1834) (Hemiptera: Cicadidae) is a forest-dwelling platypleurine cicada that uses its calling song to form choruses and attract mates. Additionally, P. semiclara produces an encounter call that is involved in courtship and also in spacing males within choruses. Males generally call from exposed trunks and branches within the understory but clear of the undergrowth and fight with other males that call within about 50 cm of them. Choruses sing sporadically throughout the day but focus most of their calling activity into half-hour bouts at dawn and dusk. Body size and ambient temperature had no significant effect on spectral or temporal characteristics of the calling song. Body temperature measurements indicate that P. semiclara thermoregulates endothermically, with a body temperature of more than 22 °C above ambient temperature being measured during calling activity at dusk. Such endothermy provides an advantage to the cicadas by allowing them to call during crepuscular hours when atmospheric conditions are most optimal for acoustic communication and predation risks are minimal. Coincidentally, endogenously regulating body temperature allows the temporal characteristics of the call to be unaffected by ambient temperature changes.
- Full Text:
- Date Issued: 2003
Larval development of the carrion-breeding flesh fly, Sarcophaga (Liosarcophaga) tibialis Macquart (Diptera: Sarcophagidae), at constant temperatures
- Villet, Martin H, MacKenzie, B, Muller, Wilhelmine J
- Authors: Villet, Martin H , MacKenzie, B , Muller, Wilhelmine J
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7091 , http://hdl.handle.net/10962/d1012422
- Description: Larvae of Sarcophaga (Liosarcophaga) tibialis Macquart were raised on chicken liver under six different constant temperatures. Maximum survival indicated an optimal developmental temperature of near 20°C, while trends in mortality, larval length and larval mass implied that the thermal window for successful development lay between 15°C and 30°C. Using a recently described method to estimate a simple thermal summation model, it was found that the timing of the end of the feeding phase could be estimated by a developmental zero (D0) of 5.2°C (S.E. = 1.21) and a thermal summation constant (K) of 106.4 d°C (S.E. = 8.31) and of the end of the wandering phase by D0 = 4.1°C (S.E. = 0.39) and K = 126.7 d°C (S.E. = 3.28). Published development times at constant temperatures were compiled for 19 other species of flesh flies, and the developmental constants were calculated for six species for which sufficient data were accumulated.
- Full Text:
- Date Issued: 2006
- Authors: Villet, Martin H , MacKenzie, B , Muller, Wilhelmine J
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7091 , http://hdl.handle.net/10962/d1012422
- Description: Larvae of Sarcophaga (Liosarcophaga) tibialis Macquart were raised on chicken liver under six different constant temperatures. Maximum survival indicated an optimal developmental temperature of near 20°C, while trends in mortality, larval length and larval mass implied that the thermal window for successful development lay between 15°C and 30°C. Using a recently described method to estimate a simple thermal summation model, it was found that the timing of the end of the feeding phase could be estimated by a developmental zero (D0) of 5.2°C (S.E. = 1.21) and a thermal summation constant (K) of 106.4 d°C (S.E. = 8.31) and of the end of the wandering phase by D0 = 4.1°C (S.E. = 0.39) and K = 126.7 d°C (S.E. = 3.28). Published development times at constant temperatures were compiled for 19 other species of flesh flies, and the developmental constants were calculated for six species for which sufficient data were accumulated.
- Full Text:
- Date Issued: 2006