The influence of temperature in the ecology of the intermediate host snails of Schistosoma and Fasciola (Trematoda) in southern Rhodesia
- Authors: Shiff, Clive Julian
- Date: 1963
- Subjects: Schistosoma , Schistosomiasis , Fasciola , Snails -- Zimbabwe , Trematoda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5881 , http://hdl.handle.net/10962/d1013208
- Description: The influence of temperature on the bionomics of Bulinus (Physopsis) globosus, Biomphalaria pfeifferi and Lymnaea natalensis has been studied both in the laboratory under controlled conditions and in the field under normal seasonal influences. Field studies were carried out in two different localities, one a semi-permanent pond and the other a temporary waterbody. For this purpose a sampling implement was developed. The results show the seasonal progression of these populations both with respect to estimated numbers and the size distribution of the snails. The rate of actual increase at different seasons was calculated for the three species where the data were sufficient. In the laboratory the snails were maintained at various temperatures, other conditions being kept standard. Daily records of mortality and fecundity of various cohorts reared from the egg stage enabled the compilation of life tables fof the speciesand from these data were calcualted the intrinsic rate of natural increase and other parameters. Effects of crowding in aquaria were studied. From the data obtained in the laboratory it was possible to predict the distribution and population potential for each species for snail of various environmental conditions. These predictions were, in fact, confirmed by field observation.
- Full Text:
- Date Issued: 1963
- Authors: Shiff, Clive Julian
- Date: 1963
- Subjects: Schistosoma , Schistosomiasis , Fasciola , Snails -- Zimbabwe , Trematoda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5881 , http://hdl.handle.net/10962/d1013208
- Description: The influence of temperature on the bionomics of Bulinus (Physopsis) globosus, Biomphalaria pfeifferi and Lymnaea natalensis has been studied both in the laboratory under controlled conditions and in the field under normal seasonal influences. Field studies were carried out in two different localities, one a semi-permanent pond and the other a temporary waterbody. For this purpose a sampling implement was developed. The results show the seasonal progression of these populations both with respect to estimated numbers and the size distribution of the snails. The rate of actual increase at different seasons was calculated for the three species where the data were sufficient. In the laboratory the snails were maintained at various temperatures, other conditions being kept standard. Daily records of mortality and fecundity of various cohorts reared from the egg stage enabled the compilation of life tables fof the speciesand from these data were calcualted the intrinsic rate of natural increase and other parameters. Effects of crowding in aquaria were studied. From the data obtained in the laboratory it was possible to predict the distribution and population potential for each species for snail of various environmental conditions. These predictions were, in fact, confirmed by field observation.
- Full Text:
- Date Issued: 1963
The dramatic theory of William Hazlitt : "Imagination in criticism"
- Authors: De Villiers, André
- Date: 1964
- Subjects: Hazlitt, William, 1778-1830 , Drama -- History and criticism -- 19th century , English drama -- History and criticism -- 19th century
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2320 , http://hdl.handle.net/10962/d1013383
- Full Text:
- Date Issued: 1964
- Authors: De Villiers, André
- Date: 1964
- Subjects: Hazlitt, William, 1778-1830 , Drama -- History and criticism -- 19th century , English drama -- History and criticism -- 19th century
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2320 , http://hdl.handle.net/10962/d1013383
- Full Text:
- Date Issued: 1964
The Lumwana Copper Prospect in Zambia
- Authors: McGregor, James Archibald
- Date: 1965
- Subjects: Copper -- Zambia , Copper ores -- Zambia -- Analysis , Copper mines and mining -- Zambia , Mineralogy -- Zambia , Geology, Economic -- Zambia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5072 , http://hdl.handle.net/10962/d1013507
- Description: The Lumwana copper orebody is situated 170 miles west of the Copperbelt. It is stratiform and occurs in schists regarded as part of the Katanga System older than the lower-most Copperbelt quartzite. The discovery of copper at the Lumwana Prospect was a text book example of the success of the R.S.T. Mines Services Limited prospecting techniques. These include partial geochemical analyses of soil and drainage samples, pitting, drilling and radiometric, self potential, magnetic, resistivity and induced polarization methods of geophysical exploration. The copper-bearing formations at the Lumwana Prospect occur in the inverted limb of a great recumbent fold within the Mombezhi Dome. Three periods of folding are recognized from the study of regional foliations and lineation, and the attitude of fold elements in individual folds. Each period of folding is regarded as a major pulse in the Lufilian Orogeny. The first-formed folds are isoclinal and have axial planes which strike at 160°, and dip southwest at 15°; the plunge is 11° in a direction 212° . The formation of first folds was accompanied by thrust faulting and the development of nappe structures including the great Lumwana recumbent fold. The second folds have axial planes which strike at 170° and dip west at 44°, the plunge is 12° in a direction of 192°, and the folds tend to be overturned. The third folds cut across the earlier folds at variable angles, they are overturned to the north and have axial planes which dip gently to the south. The formation of third folds was such that northward-acting stress was rotated from southeast to southwest, and relaxation of this stress resulted in the development in competent strata of joints which strike at 120° and dip steeply. At the Lumwana Prospect the northward-acting Lufilian stress is thought to have been resolved into eastward acting stress during first and second folding as a result of compression near the centre of the Lufilian Arc. The third folds are the normal Lufilian folds sub-parallel to the Lufilian Arc. Normal faulting and intrusion of gabbro along planes of these faults and the earlier thrust faults eccurred in a post-Lufilian tensional phase. In recent times warping of the formations at Lumwana has occurred on east-west axes. Statistical examination of chemical data on fifty-four composite samples of mineralized rock from drill-holes reveals that the distribution of copper, iron and sulphur is related to that of potash and soda. These relationships can be explained on sedimentological grounds since the examination of the distribution of soda and potash in these and other horizons yields no evidence of metasomatism in the mineralized horizon. Intrusive into the mineralized schists, though not found in the ore, are thin amphibolites and a large serpentinite which contains relict olivine and bronzite. This is the first recorded occurrence of ultrabasic rocks in the Lower Roan Group of the Katanga System in this part of Zambia. Study of all formations at the Lumwana Prospect reveals that they have been metamorphosed in the epidote-amphibolite facies of regional metamorphism. Mineral assemblages indicative of the amphibolite facies are found in sheared rocks, and metamorphism in competent parts of the Upper Roan-Mwashia has been confined to the greenschist facies. Temperatures of metamorphism are estimated to have been between 250° and 280°C, and pressures are likely to have exceeded 6 kilobars. Evidence of metasomatism, absent in the Lower Roan, is found in the examination of the Upper Roan-Mwashia formations. Metasomatism includes scapolitization and albitization and is related to the intrusion of gabbro into these sediments, but does not necessarily involve exogenous material. The sulphide minerals identified are bornite, chalcocite, digenite, covellite, chalcopyrite, cubanite, valleriite, carrollite, pyrite and pyrrhotite. Intergrowths of these minerals have resulted from metamorphism at temperatures slightly in excess of 235°C. The copper sulphides are distributed zonally in the orebody with chalcocite- bornite ore where the mineralized schist is thin, and chalcopyrite- cubanite-pyrite ore where it is thick. Vertically the body contains horizons with sulphides relatively rich in copper at the top and bottom, and an intermediate zone with sulphides leaner in copper. This zonal distribution is considered to be evidence for syngenetic deposition of copper during successive cycles of transgression and regression. Ore genesis at Lumwana is closely related to genesis of the Copperbelt and Katanga orebodies. The Zambia-Katanga province is considered to have been enriched in copper epigenetically prior to the formation of the present-day orebodies. Reworking of these cupriferous rocks and some early-formed syngenetic deposits of which Lumwana is one, is considered to have played a major role in producing the present-day copper orebodies.
- Full Text:
- Date Issued: 1965
- Authors: McGregor, James Archibald
- Date: 1965
- Subjects: Copper -- Zambia , Copper ores -- Zambia -- Analysis , Copper mines and mining -- Zambia , Mineralogy -- Zambia , Geology, Economic -- Zambia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5072 , http://hdl.handle.net/10962/d1013507
- Description: The Lumwana copper orebody is situated 170 miles west of the Copperbelt. It is stratiform and occurs in schists regarded as part of the Katanga System older than the lower-most Copperbelt quartzite. The discovery of copper at the Lumwana Prospect was a text book example of the success of the R.S.T. Mines Services Limited prospecting techniques. These include partial geochemical analyses of soil and drainage samples, pitting, drilling and radiometric, self potential, magnetic, resistivity and induced polarization methods of geophysical exploration. The copper-bearing formations at the Lumwana Prospect occur in the inverted limb of a great recumbent fold within the Mombezhi Dome. Three periods of folding are recognized from the study of regional foliations and lineation, and the attitude of fold elements in individual folds. Each period of folding is regarded as a major pulse in the Lufilian Orogeny. The first-formed folds are isoclinal and have axial planes which strike at 160°, and dip southwest at 15°; the plunge is 11° in a direction 212° . The formation of first folds was accompanied by thrust faulting and the development of nappe structures including the great Lumwana recumbent fold. The second folds have axial planes which strike at 170° and dip west at 44°, the plunge is 12° in a direction of 192°, and the folds tend to be overturned. The third folds cut across the earlier folds at variable angles, they are overturned to the north and have axial planes which dip gently to the south. The formation of third folds was such that northward-acting stress was rotated from southeast to southwest, and relaxation of this stress resulted in the development in competent strata of joints which strike at 120° and dip steeply. At the Lumwana Prospect the northward-acting Lufilian stress is thought to have been resolved into eastward acting stress during first and second folding as a result of compression near the centre of the Lufilian Arc. The third folds are the normal Lufilian folds sub-parallel to the Lufilian Arc. Normal faulting and intrusion of gabbro along planes of these faults and the earlier thrust faults eccurred in a post-Lufilian tensional phase. In recent times warping of the formations at Lumwana has occurred on east-west axes. Statistical examination of chemical data on fifty-four composite samples of mineralized rock from drill-holes reveals that the distribution of copper, iron and sulphur is related to that of potash and soda. These relationships can be explained on sedimentological grounds since the examination of the distribution of soda and potash in these and other horizons yields no evidence of metasomatism in the mineralized horizon. Intrusive into the mineralized schists, though not found in the ore, are thin amphibolites and a large serpentinite which contains relict olivine and bronzite. This is the first recorded occurrence of ultrabasic rocks in the Lower Roan Group of the Katanga System in this part of Zambia. Study of all formations at the Lumwana Prospect reveals that they have been metamorphosed in the epidote-amphibolite facies of regional metamorphism. Mineral assemblages indicative of the amphibolite facies are found in sheared rocks, and metamorphism in competent parts of the Upper Roan-Mwashia has been confined to the greenschist facies. Temperatures of metamorphism are estimated to have been between 250° and 280°C, and pressures are likely to have exceeded 6 kilobars. Evidence of metasomatism, absent in the Lower Roan, is found in the examination of the Upper Roan-Mwashia formations. Metasomatism includes scapolitization and albitization and is related to the intrusion of gabbro into these sediments, but does not necessarily involve exogenous material. The sulphide minerals identified are bornite, chalcocite, digenite, covellite, chalcopyrite, cubanite, valleriite, carrollite, pyrite and pyrrhotite. Intergrowths of these minerals have resulted from metamorphism at temperatures slightly in excess of 235°C. The copper sulphides are distributed zonally in the orebody with chalcocite- bornite ore where the mineralized schist is thin, and chalcopyrite- cubanite-pyrite ore where it is thick. Vertically the body contains horizons with sulphides relatively rich in copper at the top and bottom, and an intermediate zone with sulphides leaner in copper. This zonal distribution is considered to be evidence for syngenetic deposition of copper during successive cycles of transgression and regression. Ore genesis at Lumwana is closely related to genesis of the Copperbelt and Katanga orebodies. The Zambia-Katanga province is considered to have been enriched in copper epigenetically prior to the formation of the present-day orebodies. Reworking of these cupriferous rocks and some early-formed syngenetic deposits of which Lumwana is one, is considered to have played a major role in producing the present-day copper orebodies.
- Full Text:
- Date Issued: 1965
The relationship between acquired resistance and transmission of Schistosoma Weinland, 1858, in man and its influences on the prevalence of S Capense (Harley, 1864) and S Mansoni Sambon, 1907, in Southern Rhodesia
- Authors: Clarke, H V de V
- Date: 1965
- Subjects: Platyhelminthes , Schistosoma , Schistosomiasis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5842 , http://hdl.handle.net/10962/d1010500 , Platyhelminthes , Schistosoma , Schistosomiasis
- Description: Bilharziasis ranks with Tuberculosis and Malaria as the three most important endemic diseases of man in Rhodesia. The prominence given to bilharziasis in the endemic diseases pattern arises from its high prevalence, particularly in the African population. It is probable that bilharziasis was endemic in the country even prior to the arrival in the conntry of the European settlers in 1890, but it was not until Orpen (1915) described the results of a small survey that local infections were proven. He reported 182 (31 percent) urinary infections in 592 African prisoners examined in the Salisbury gaol. In the ensuing 15 years there was only scanty evidence of the prevalence of the disease. However, in the decade 1931 to 1940 the Annual Public Health Reports of Southern Rhodesia indicated increasing prevalence, and this stimulated interest in the problem and led to the establishment in 1939 of a specialised laboratory to study the parasites causing the disease. The unpublished records of this laboratory indicate that in more recent years the disease has increased not only in prevalence but also in its intensity in infected individuals. Surveys show that the urinary form of the disease is more widespread than the intestinal form. Both forms are becoming more prevalent but the rapid increase of the latter, considered by most authorities to be the more severe, indicates that a greater importance must be accorded to it in the future. Introduction, p. 1.
- Full Text:
- Date Issued: 1965
- Authors: Clarke, H V de V
- Date: 1965
- Subjects: Platyhelminthes , Schistosoma , Schistosomiasis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5842 , http://hdl.handle.net/10962/d1010500 , Platyhelminthes , Schistosoma , Schistosomiasis
- Description: Bilharziasis ranks with Tuberculosis and Malaria as the three most important endemic diseases of man in Rhodesia. The prominence given to bilharziasis in the endemic diseases pattern arises from its high prevalence, particularly in the African population. It is probable that bilharziasis was endemic in the country even prior to the arrival in the conntry of the European settlers in 1890, but it was not until Orpen (1915) described the results of a small survey that local infections were proven. He reported 182 (31 percent) urinary infections in 592 African prisoners examined in the Salisbury gaol. In the ensuing 15 years there was only scanty evidence of the prevalence of the disease. However, in the decade 1931 to 1940 the Annual Public Health Reports of Southern Rhodesia indicated increasing prevalence, and this stimulated interest in the problem and led to the establishment in 1939 of a specialised laboratory to study the parasites causing the disease. The unpublished records of this laboratory indicate that in more recent years the disease has increased not only in prevalence but also in its intensity in infected individuals. Surveys show that the urinary form of the disease is more widespread than the intestinal form. Both forms are becoming more prevalent but the rapid increase of the latter, considered by most authorities to be the more severe, indicates that a greater importance must be accorded to it in the future. Introduction, p. 1.
- Full Text:
- Date Issued: 1965
Xhosa-English pronunciation in the south-east Cape
- Authors: Hundleby, C E
- Date: 1965
- Subjects: Xhosa language -- Pronunciation by foreign speakers English language -- Pronunciation by foreign speakers
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2303 , http://hdl.handle.net/10962/d1012467
- Description: The thesis mainly concerns itself with an analysis of the present day pronunciation of Xhosa-English. The isolation and identification of the segmental phonemes and the phonemes of stress, intonation and transition form the core of the work. The author has attempted to give continuity by introducing a subsidiary theme, the Lado hypothesis as stated on page 1. In conformity with the the methodology imposed by the Lado formula, it was first necessary to establish two things: first, a standard background against which the characteristics of XEP could be compared, and secondly, to give briefly, but in sufficient detail for our purpose, the main phonological features of the mother tongue.
- Full Text:
- Date Issued: 1965
- Authors: Hundleby, C E
- Date: 1965
- Subjects: Xhosa language -- Pronunciation by foreign speakers English language -- Pronunciation by foreign speakers
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2303 , http://hdl.handle.net/10962/d1012467
- Description: The thesis mainly concerns itself with an analysis of the present day pronunciation of Xhosa-English. The isolation and identification of the segmental phonemes and the phonemes of stress, intonation and transition form the core of the work. The author has attempted to give continuity by introducing a subsidiary theme, the Lado hypothesis as stated on page 1. In conformity with the the methodology imposed by the Lado formula, it was first necessary to establish two things: first, a standard background against which the characteristics of XEP could be compared, and secondly, to give briefly, but in sufficient detail for our purpose, the main phonological features of the mother tongue.
- Full Text:
- Date Issued: 1965
A comparison of the female characters in Plautus and in Terence
- Authors: Slatter, E M
- Date: 1966
- Subjects: Plautus, Titus Maccius Terence Plautus, Titus Maccius -- Characters -- Women Terence -- Characters -- Women Latin drama Women in literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3602 , http://hdl.handle.net/10962/d1002186
- Full Text:
- Date Issued: 1966
- Authors: Slatter, E M
- Date: 1966
- Subjects: Plautus, Titus Maccius Terence Plautus, Titus Maccius -- Characters -- Women Terence -- Characters -- Women Latin drama Women in literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3602 , http://hdl.handle.net/10962/d1002186
- Full Text:
- Date Issued: 1966
A study of irradiation effects in solids
- Authors: Brown, Michael Ewart
- Date: 1966
- Subjects: Decomposition (Chemistry) , Crystals -- Thermal properties , Oxalates -- Thermal properties , Solids -- Effect of radiation on
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4509 , http://hdl.handle.net/10962/d1013387
- Description: One of the primary objects of this research was to determine, if possible, the nature of the radiation damage prior to thermal decomposition. The X-ray study has not wholly achieved this although more information has been derived from it than from similar work on AgMnO₄ However, the diffuse reflections obtained do indicate, quite strongly, the creation of point defects during irradiation. This is of value since such assumptions have been made in the explanation of the kinetics of decomposition of a number of irradiated solids (BaN₆,CaN₆). In addition the X-ray work has suggested future research which should produce useful information; namely, a precise study of the diffuse reflections. Another object of the research was to attempt to determine what characteristics, if any, of the kinetics of the decomposition of an unirradiated solid would predetermine a marked irradiation effect. It is obvious that the type of nuclear growth which occurs e.g. branching chain, or power law, does not characterise a substance with regard to a possible irradiation effect . The photosensitivity, or otherwise, also does not determine whether there will be an irradiation effect. However, the one property that the substances which have been studied, have in common, is a polyatomic anion, but here again ammonium dichromate does not show an acceleration of the decomposition after irradiation. Consequently it is considered that it is not possible to say, a priori, whether a solid will undergo an accelerated decomposition after irradiation. Each new solid, unless it belongs to a particular class e.g. the alkaline earth azides , must be considered afresh. Nevertheless it does appear that the irradiation effect can take two forms: - (i) the production of an unstable compound e.g. nickel oxalate, the decomposition of which affects the normal pyrolysis; and (ii) the production of point defects which determine the nature of the subsequent thermal decomposition e.g . CaN₆ . It is possible that the effect requires an interaction of the created point defects with the existing line defects.
- Full Text:
- Date Issued: 1966
- Authors: Brown, Michael Ewart
- Date: 1966
- Subjects: Decomposition (Chemistry) , Crystals -- Thermal properties , Oxalates -- Thermal properties , Solids -- Effect of radiation on
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4509 , http://hdl.handle.net/10962/d1013387
- Description: One of the primary objects of this research was to determine, if possible, the nature of the radiation damage prior to thermal decomposition. The X-ray study has not wholly achieved this although more information has been derived from it than from similar work on AgMnO₄ However, the diffuse reflections obtained do indicate, quite strongly, the creation of point defects during irradiation. This is of value since such assumptions have been made in the explanation of the kinetics of decomposition of a number of irradiated solids (BaN₆,CaN₆). In addition the X-ray work has suggested future research which should produce useful information; namely, a precise study of the diffuse reflections. Another object of the research was to attempt to determine what characteristics, if any, of the kinetics of the decomposition of an unirradiated solid would predetermine a marked irradiation effect. It is obvious that the type of nuclear growth which occurs e.g. branching chain, or power law, does not characterise a substance with regard to a possible irradiation effect . The photosensitivity, or otherwise, also does not determine whether there will be an irradiation effect. However, the one property that the substances which have been studied, have in common, is a polyatomic anion, but here again ammonium dichromate does not show an acceleration of the decomposition after irradiation. Consequently it is considered that it is not possible to say, a priori, whether a solid will undergo an accelerated decomposition after irradiation. Each new solid, unless it belongs to a particular class e.g. the alkaline earth azides , must be considered afresh. Nevertheless it does appear that the irradiation effect can take two forms: - (i) the production of an unstable compound e.g. nickel oxalate, the decomposition of which affects the normal pyrolysis; and (ii) the production of point defects which determine the nature of the subsequent thermal decomposition e.g . CaN₆ . It is possible that the effect requires an interaction of the created point defects with the existing line defects.
- Full Text:
- Date Issued: 1966
An examination of the extractives of Leonotis species
- Authors: Kaplan, Errol R
- Date: 1966
- Subjects: Leonotis -- Analysis Botanical chemistry Chemistry, Analytic Chemistry, Organic
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4481 , http://hdl.handle.net/10962/d1012628
- Description: Marrubiin and the other two diterpenoids, compounds X and Y, which had previously been isolated from Leonotus leonurus have been reinvestigated. Although the structure for marrubiin is well known its stereochemistry has been the subject of protracted discussion and is by no means secure except at C₅ and C₁₀ . N.M.R. spectral evidence showed that the lactone ring was cis-fused and β-orientated. Dehydration experiments carried out by previous workers were repeated, in order to resolve the residual uncertainty regarding the stereochemistry at C₉, an attempt was made to prepare iodoacetyl marrubic acid for X-ray crystallographic studies. Compound Y, C₂₀H₂₈0₃, a triply-unsaturated compound was shown by spectral studies to contain a furan ring and an α,β- unsaturated keto-group. It possesses a hydroxyl group incapable of acetylation, but readily removed by alkali and dehydrating agents to yield a tetraunsaturated compound, anhydro~Y; the hydroxyl is thus tertiary, Isolation of 1:2:5-trimethylnaphthalene on dehydrogenation indicated a relationship with the labdane diterpene group and supported the C₂₀ formula, The position of the α,β-unsaturated keto-group was resolved by interpretation of the ultraviolet spectra of degradation products and also by isolation of 1:2:3:5- trimethylnaphthalene on dehydrogenation of a suitable grignard product, The presence of a β-substituted furan was further indicated by colour reactions and confirmed by mass and n.m.r. spectra. The skeleton of compound Y is correlated with marrubiin via "iso-ambreinolide " and its stereochemistry is discussed. Further stereochemical assignments are postulated from the study of the n.m.r. spectra. Compound X, C₂₀H₂₈0₅, was shown by spectral and chemical evidence to be a diterpenoid dilactone containing an ether bridge between C₉ and C₁₃ Isolation of 1:2:5 trimethylnaphthal ene on dehydrogenation showed it to be closely related to marrubiin, This was supported by n.m.r. spectral results. A structure for compound X is proposed and the stereochemistry discussed. The aerial portions of Leonotis leonitis were also extracted and shown to contain a new compound, compound R. Preliminary investigation showed that it was a dilactone containing a furan ring, The n.m.r. spectrum of the compound is discussed.
- Full Text:
- Date Issued: 1966
- Authors: Kaplan, Errol R
- Date: 1966
- Subjects: Leonotis -- Analysis Botanical chemistry Chemistry, Analytic Chemistry, Organic
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4481 , http://hdl.handle.net/10962/d1012628
- Description: Marrubiin and the other two diterpenoids, compounds X and Y, which had previously been isolated from Leonotus leonurus have been reinvestigated. Although the structure for marrubiin is well known its stereochemistry has been the subject of protracted discussion and is by no means secure except at C₅ and C₁₀ . N.M.R. spectral evidence showed that the lactone ring was cis-fused and β-orientated. Dehydration experiments carried out by previous workers were repeated, in order to resolve the residual uncertainty regarding the stereochemistry at C₉, an attempt was made to prepare iodoacetyl marrubic acid for X-ray crystallographic studies. Compound Y, C₂₀H₂₈0₃, a triply-unsaturated compound was shown by spectral studies to contain a furan ring and an α,β- unsaturated keto-group. It possesses a hydroxyl group incapable of acetylation, but readily removed by alkali and dehydrating agents to yield a tetraunsaturated compound, anhydro~Y; the hydroxyl is thus tertiary, Isolation of 1:2:5-trimethylnaphthalene on dehydrogenation indicated a relationship with the labdane diterpene group and supported the C₂₀ formula, The position of the α,β-unsaturated keto-group was resolved by interpretation of the ultraviolet spectra of degradation products and also by isolation of 1:2:3:5- trimethylnaphthalene on dehydrogenation of a suitable grignard product, The presence of a β-substituted furan was further indicated by colour reactions and confirmed by mass and n.m.r. spectra. The skeleton of compound Y is correlated with marrubiin via "iso-ambreinolide " and its stereochemistry is discussed. Further stereochemical assignments are postulated from the study of the n.m.r. spectra. Compound X, C₂₀H₂₈0₅, was shown by spectral and chemical evidence to be a diterpenoid dilactone containing an ether bridge between C₉ and C₁₃ Isolation of 1:2:5 trimethylnaphthal ene on dehydrogenation showed it to be closely related to marrubiin, This was supported by n.m.r. spectral results. A structure for compound X is proposed and the stereochemistry discussed. The aerial portions of Leonotis leonitis were also extracted and shown to contain a new compound, compound R. Preliminary investigation showed that it was a dilactone containing a furan ring, The n.m.r. spectrum of the compound is discussed.
- Full Text:
- Date Issued: 1966
An investigation of the judgement of a sample of South African adolescent schoolchildren in certain areas of moral behaviour
- Authors: Hayward, Fritz Reitz
- Date: 1966
- Subjects: Teenagers -- South Africa -- Attitudes , Youth -- South Africa -- Conduct of life , Multiculturalism -- Moral and ethical aspects , Moral education -- South Africa , Moral development -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1998 , http://hdl.handle.net/10962/d1015009
- Description: A. The Aims The modern adolescent is frequently accused of being morally lax; his judgement of moral issues is held in question; and parents, church and school are accused of having lost their influence on present-day youth. The writer wes lnterested in finding out whether these accusations could in fact be substantiated amongst a sample of adolescent school-children in a selected urban area. The aims of the research, therefore, were as follows :- (i) to investigate the judgement of these adolescents in certain given areas of moral behaviour, (ii) to determine whether there were any appreciable differences between the Afrikaans-speaking and English-speaking adolescents of the sample in their judgements of these moral issues, (iii) to determine whether there were any appreciable differences between adolescent boys and girls of the sample in their judgement of these moral issues, (iv) to explore the influences which caused the tested adolescents to re-act as they did.
- Full Text:
- Date Issued: 1966
- Authors: Hayward, Fritz Reitz
- Date: 1966
- Subjects: Teenagers -- South Africa -- Attitudes , Youth -- South Africa -- Conduct of life , Multiculturalism -- Moral and ethical aspects , Moral education -- South Africa , Moral development -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1998 , http://hdl.handle.net/10962/d1015009
- Description: A. The Aims The modern adolescent is frequently accused of being morally lax; his judgement of moral issues is held in question; and parents, church and school are accused of having lost their influence on present-day youth. The writer wes lnterested in finding out whether these accusations could in fact be substantiated amongst a sample of adolescent school-children in a selected urban area. The aims of the research, therefore, were as follows :- (i) to investigate the judgement of these adolescents in certain given areas of moral behaviour, (ii) to determine whether there were any appreciable differences between the Afrikaans-speaking and English-speaking adolescents of the sample in their judgements of these moral issues, (iii) to determine whether there were any appreciable differences between adolescent boys and girls of the sample in their judgement of these moral issues, (iv) to explore the influences which caused the tested adolescents to re-act as they did.
- Full Text:
- Date Issued: 1966
Genadendal and its satellites : a history of the Moravian Mission stations at the Cape, 1737-1869
- Authors: Krüger, Bernhard
- Date: 1966
- Subjects: Moravians -- Missions -- South Africa -- Genadendal , Missions -- South Africa -- History , Genadendal (South Africa) -- History , Cape of Good Hope (South Africa) -- History -- To 1795 , Cape of Good Hope (South Africa) -- History -- 1795-1872
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1284 , http://hdl.handle.net/10962/d1013470
- Description: J,F.w. Kühn, a member of the Moravian Mission Board, wrote in 1871 to the Superintendent at Genadendal that the closed settlements in South Africa were a precious and unique feature of mission work for which the brethren should be grateful. While he had been at the Gape, he had suffered under the difficulties of their management, but from the distance, and in comparison with mission work elsewhere, he had learnt to appreciate them as a great blessing. The questions arise: How dld they originate, develop and survive for so long? What were their characteristics, advantages and limitations? What factors contributed to their development? How did they fit into their milieu and influence it? The following thesis is an effort to give a detailed history of their development and an appraisal. I have endeavoured to give a vivid picture of personalities and events within the limits of historical correctness, because I consider it the noblest aim of historical research to confront us with the past in such a way that personal understanding becomes possible. In as much as we meet those who have made history. or have been part of it, in person, we can arrive at a deeper appreciation of their achievements, problems and failures.
- Full Text:
- Date Issued: 1966
- Authors: Krüger, Bernhard
- Date: 1966
- Subjects: Moravians -- Missions -- South Africa -- Genadendal , Missions -- South Africa -- History , Genadendal (South Africa) -- History , Cape of Good Hope (South Africa) -- History -- To 1795 , Cape of Good Hope (South Africa) -- History -- 1795-1872
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1284 , http://hdl.handle.net/10962/d1013470
- Description: J,F.w. Kühn, a member of the Moravian Mission Board, wrote in 1871 to the Superintendent at Genadendal that the closed settlements in South Africa were a precious and unique feature of mission work for which the brethren should be grateful. While he had been at the Gape, he had suffered under the difficulties of their management, but from the distance, and in comparison with mission work elsewhere, he had learnt to appreciate them as a great blessing. The questions arise: How dld they originate, develop and survive for so long? What were their characteristics, advantages and limitations? What factors contributed to their development? How did they fit into their milieu and influence it? The following thesis is an effort to give a detailed history of their development and an appraisal. I have endeavoured to give a vivid picture of personalities and events within the limits of historical correctness, because I consider it the noblest aim of historical research to confront us with the past in such a way that personal understanding becomes possible. In as much as we meet those who have made history. or have been part of it, in person, we can arrive at a deeper appreciation of their achievements, problems and failures.
- Full Text:
- Date Issued: 1966
Ionospheric effects in the Southern radiation anomaly
- Authors: Torr, Douglas G
- Date: 1966
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5540 , http://hdl.handle.net/10962/d1013305
- Description: From introduction: As ionosphericist on the 4th South African National Antarctic Expedition, I spent twelve months at Sanae (70°18'S, 2°2l'W, L= 4) in 1963. In the course of routine vertical incidence soundings, it was noticed with some surprise that the frequency of occurrence of ionospheric blackouts was unexpectedly high. Initially this aroused considerable concern about the reliability of the equipment. In fact it has been · observed that some stations lying in and near the Southern Radiation Anomaly report such occasions as records lost due to non-ionospheric reasons. Coincidently, however, Gledhill and van Rooyen (1963), also of Rhodes University, predicted ionospheric irregularities and other geophysical phenomena in a region around Sanae where Ginsburg et al. (1962) observed high intensities of charged particles with Sputniks 5 and 6.
- Full Text:
- Date Issued: 1966
- Authors: Torr, Douglas G
- Date: 1966
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5540 , http://hdl.handle.net/10962/d1013305
- Description: From introduction: As ionosphericist on the 4th South African National Antarctic Expedition, I spent twelve months at Sanae (70°18'S, 2°2l'W, L= 4) in 1963. In the course of routine vertical incidence soundings, it was noticed with some surprise that the frequency of occurrence of ionospheric blackouts was unexpectedly high. Initially this aroused considerable concern about the reliability of the equipment. In fact it has been · observed that some stations lying in and near the Southern Radiation Anomaly report such occasions as records lost due to non-ionospheric reasons. Coincidently, however, Gledhill and van Rooyen (1963), also of Rhodes University, predicted ionospheric irregularities and other geophysical phenomena in a region around Sanae where Ginsburg et al. (1962) observed high intensities of charged particles with Sputniks 5 and 6.
- Full Text:
- Date Issued: 1966
Johannes van Melle : realist tussen twee werelden
- Authors: Jonckheere, W F
- Date: 1966
- Subjects: Van Melle, J. (Johannes),1887-1953
- Language: Dutch
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3645 , http://hdl.handle.net/10962/d1015200
- Description: [From Introduction]. Aan het werk van Johannes Van Melle is tot dusver geen allesomvattende studie gewijd. Het is vooral in dit tekort dat het onderhavige proefschrift wil voorzien. Reeds vroeger hebben enkelen hun aandacht op onderdelen van Van Melles proza gericht maar niemand heeft eft ooit ondernomen de hele reeks van Van Melles gepubliceerde en ongepubliceerde gechriften te onderzoeken en deze zowel in hun samenhang als afzonderlijk naar waarde te schatten.
- Full Text:
- Date Issued: 1966
- Authors: Jonckheere, W F
- Date: 1966
- Subjects: Van Melle, J. (Johannes),1887-1953
- Language: Dutch
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3645 , http://hdl.handle.net/10962/d1015200
- Description: [From Introduction]. Aan het werk van Johannes Van Melle is tot dusver geen allesomvattende studie gewijd. Het is vooral in dit tekort dat het onderhavige proefschrift wil voorzien. Reeds vroeger hebben enkelen hun aandacht op onderdelen van Van Melles proza gericht maar niemand heeft eft ooit ondernomen de hele reeks van Van Melles gepubliceerde en ongepubliceerde gechriften te onderzoeken en deze zowel in hun samenhang als afzonderlijk naar waarde te schatten.
- Full Text:
- Date Issued: 1966
Studies in Gusii kinship
- Authors: Mayer, Iona
- Date: 1966
- Subjects: Gusii (African people) -- Kinship
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2119 , http://hdl.handle.net/10962/d1012846
- Description: This thesis has two aims. In Part I the aim is to present some unpublished field material on Gusii kinship, particularly on domestic relations between the generations and the sexes. In Part II the aim is to clarify a theoretical model of 'relation by kinship', and of ' kinship categories" and 'classificntion', based on an examination of the ways in which Gusii use kinship terms. Intro., p. 1.
- Full Text:
- Date Issued: 1966
- Authors: Mayer, Iona
- Date: 1966
- Subjects: Gusii (African people) -- Kinship
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2119 , http://hdl.handle.net/10962/d1012846
- Description: This thesis has two aims. In Part I the aim is to present some unpublished field material on Gusii kinship, particularly on domestic relations between the generations and the sexes. In Part II the aim is to clarify a theoretical model of 'relation by kinship', and of ' kinship categories" and 'classificntion', based on an examination of the ways in which Gusii use kinship terms. Intro., p. 1.
- Full Text:
- Date Issued: 1966
The thermal decomposition of mercuric oxalate and inorganic azides
- Authors: Moore, D J
- Date: 1966
- Subjects: Decomposition (Chemistry) , Oxalates -- Thermal properties , Mercuric Oxide -- Azides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4483 , http://hdl.handle.net/10962/d1012878
- Description: The chemical reactivity of a solid is influenced to a marked degree by the presence of imperfections or defects in the solid. Bond strengths are considerably weaker at points of imperfection than elsewhere in the solid, and hence the initiation of reaction is favoured at these sites due to the relative ease of bond rupture. Line defects, such as edge or screw dislocations, jogs, Smekul cracks etc, are of prime importance in such changes. The surface of a solid or in intergranular boundaries, where a state of strain exists, are also favourable places for the initiation of a reaction, Point defects e.g. vacancies or interstitialions or atoms also play important roles in chemical change, often in conjuction with line defects.
- Full Text:
- Date Issued: 1966
- Authors: Moore, D J
- Date: 1966
- Subjects: Decomposition (Chemistry) , Oxalates -- Thermal properties , Mercuric Oxide -- Azides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4483 , http://hdl.handle.net/10962/d1012878
- Description: The chemical reactivity of a solid is influenced to a marked degree by the presence of imperfections or defects in the solid. Bond strengths are considerably weaker at points of imperfection than elsewhere in the solid, and hence the initiation of reaction is favoured at these sites due to the relative ease of bond rupture. Line defects, such as edge or screw dislocations, jogs, Smekul cracks etc, are of prime importance in such changes. The surface of a solid or in intergranular boundaries, where a state of strain exists, are also favourable places for the initiation of a reaction, Point defects e.g. vacancies or interstitialions or atoms also play important roles in chemical change, often in conjuction with line defects.
- Full Text:
- Date Issued: 1966
Ultraviolet specular reflectance, electronic absorption and the excitation of fluorescence in single crystals of anthracene
- Authors: Wright, W H
- Date: 1966
- Subjects: Anthracene crystals -- Fluorescence , Ultraviolet spectroscopy -- Absorption , Reflectance
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5544 , http://hdl.handle.net/10962/d1013366
- Description: From introduction: The Fluorescence Excitation Spectrum or anthracene is known to vary considerably with the age and condition or the crystal. This thesis represents an attempt to improve the understanding of these variations. To put the problem on a quantitative basis it was found necessary to know both the ultraviolet reflection and absorption spectra. Reports of the reflection spectrum appear to have been confined to the case of polarised incident light. In addition the reflectivity measurements are always reported for a freshly cleaved surface. For these reasons the reflectivity of anthracene for various conditions of the reflecting surface was measured with unpolarised light. These varying reflectivities were used to further knowledge of the chemical processes at the crystal surface, as well as being used directly in the calculation of fluorescence excitation spectra. Reflection spectra with a- and b- crystallographic axis polarisations were also obtained. Since such spectra are reported in the literature it was possible, by comparison, to conclude that the experimental methods used in this thesis yielded valid results. The polarised measurements were used to obtain optical constants for the crystal. In the interests of readability most of the complicated process of converting the reflectivities to optical constants is dealt with in three appendices to the thesis.
- Full Text:
- Date Issued: 1966
- Authors: Wright, W H
- Date: 1966
- Subjects: Anthracene crystals -- Fluorescence , Ultraviolet spectroscopy -- Absorption , Reflectance
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5544 , http://hdl.handle.net/10962/d1013366
- Description: From introduction: The Fluorescence Excitation Spectrum or anthracene is known to vary considerably with the age and condition or the crystal. This thesis represents an attempt to improve the understanding of these variations. To put the problem on a quantitative basis it was found necessary to know both the ultraviolet reflection and absorption spectra. Reports of the reflection spectrum appear to have been confined to the case of polarised incident light. In addition the reflectivity measurements are always reported for a freshly cleaved surface. For these reasons the reflectivity of anthracene for various conditions of the reflecting surface was measured with unpolarised light. These varying reflectivities were used to further knowledge of the chemical processes at the crystal surface, as well as being used directly in the calculation of fluorescence excitation spectra. Reflection spectra with a- and b- crystallographic axis polarisations were also obtained. Since such spectra are reported in the literature it was possible, by comparison, to conclude that the experimental methods used in this thesis yielded valid results. The polarised measurements were used to obtain optical constants for the crystal. In the interests of readability most of the complicated process of converting the reflectivities to optical constants is dealt with in three appendices to the thesis.
- Full Text:
- Date Issued: 1966
A contribution to the biology of the sociable weaver Philetairus socius (Latham)
- Authors: Maclean, Gordon L
- Date: 1967
- Subjects: Weaverbirds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5863 , http://hdl.handle.net/10962/d1012791
- Description: Anyone who has travelled the dusty road in the bed of the Kuruman River from Kuruman in the Northern Cape to the South West African border at Rietfontein cannot fail to have been impressed by the large communal nests of the sociable weaver Philetairus socius which adorn many of the camelthorn trees along the way. One of the earliest reports of the bird and its nest is that of Sir Andrew Smith (1849) who passed that way through what was then Latakoo (the present day Kuruman), collecting birds which he described for the first time. To him we are indebted for the first published illustrations of the sociable weaver, its nest and egg, and a brief account, not entirely accurate to be sure, of the building and occupation of the nest. This account has since been quoted at length by Shelley (1905) and by Friedmann (1930a) who accepted Smith's statements as they stood. Some years after Smith's travels, Anderson wrote (1872) that the flocks of sociable weavers " ... incubate their eggs under the same roof, which is composed by these birds of whole cartloads of grass piled on a branch of some kamel-thorn tree in one enormous mass of an irregular umbrella-shape, looking like a miniature haystack, and almost solid, but with the under surface, which is nearly flat, honeycombed all over with little cavities, which serve not only as places for incubation but also as a refuge against rain and wind". This account gives some idea of the spectacular nests built by these birds which are hardly larger than a sparrow. But, living in the dry and thinly-populated western regions of southern Africa, the sociable weaver remained a remote curiosity, the subject of casual reports and some strange ideas. Since Friedmann (1930a) studied the sociable weaver briefly in the western Transvaal, the only thorough field observations (mainly on nests and nest sites) up to the present have been those of Rudebeck (1953, 1956). Collias & Collias (1964) returned to the western Transvaal some 20 years after Friedmann's visit, but unfortunately had time for only a cursory study; their main interest was once again in the nest and its architecture. Thus, in 1964 when I joined Dr. T.J. Cade, then of Syracuse University and now of Cornell University, on his desert biology programme, he suggested that the sociable weaver be the subject of special study in the Kalahari. Here was a bird, resident in a harsh environment, living throughout the year in an extraordinary nest, and almost completely unknown biologically. Among the questions to be answered were: How is the nest started and how is it constructed? Which birds build, and how is the labour organized? What is the purpose of the elaborate nest: does it provide a micro-climate which enables the birds to survive better under arid conditions? How could such a communal nest have evolved? What is the social organization of the colony in and out of the breeding season? When do the birds breed and what factors induce breeding? What happens to the young birds after they become independent of their parents? Naturally many other questions arose as the work proceeded, but these were the main ones on which the project was initiated.
- Full Text:
- Date Issued: 1967
- Authors: Maclean, Gordon L
- Date: 1967
- Subjects: Weaverbirds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5863 , http://hdl.handle.net/10962/d1012791
- Description: Anyone who has travelled the dusty road in the bed of the Kuruman River from Kuruman in the Northern Cape to the South West African border at Rietfontein cannot fail to have been impressed by the large communal nests of the sociable weaver Philetairus socius which adorn many of the camelthorn trees along the way. One of the earliest reports of the bird and its nest is that of Sir Andrew Smith (1849) who passed that way through what was then Latakoo (the present day Kuruman), collecting birds which he described for the first time. To him we are indebted for the first published illustrations of the sociable weaver, its nest and egg, and a brief account, not entirely accurate to be sure, of the building and occupation of the nest. This account has since been quoted at length by Shelley (1905) and by Friedmann (1930a) who accepted Smith's statements as they stood. Some years after Smith's travels, Anderson wrote (1872) that the flocks of sociable weavers " ... incubate their eggs under the same roof, which is composed by these birds of whole cartloads of grass piled on a branch of some kamel-thorn tree in one enormous mass of an irregular umbrella-shape, looking like a miniature haystack, and almost solid, but with the under surface, which is nearly flat, honeycombed all over with little cavities, which serve not only as places for incubation but also as a refuge against rain and wind". This account gives some idea of the spectacular nests built by these birds which are hardly larger than a sparrow. But, living in the dry and thinly-populated western regions of southern Africa, the sociable weaver remained a remote curiosity, the subject of casual reports and some strange ideas. Since Friedmann (1930a) studied the sociable weaver briefly in the western Transvaal, the only thorough field observations (mainly on nests and nest sites) up to the present have been those of Rudebeck (1953, 1956). Collias & Collias (1964) returned to the western Transvaal some 20 years after Friedmann's visit, but unfortunately had time for only a cursory study; their main interest was once again in the nest and its architecture. Thus, in 1964 when I joined Dr. T.J. Cade, then of Syracuse University and now of Cornell University, on his desert biology programme, he suggested that the sociable weaver be the subject of special study in the Kalahari. Here was a bird, resident in a harsh environment, living throughout the year in an extraordinary nest, and almost completely unknown biologically. Among the questions to be answered were: How is the nest started and how is it constructed? Which birds build, and how is the labour organized? What is the purpose of the elaborate nest: does it provide a micro-climate which enables the birds to survive better under arid conditions? How could such a communal nest have evolved? What is the social organization of the colony in and out of the breeding season? When do the birds breed and what factors induce breeding? What happens to the young birds after they become independent of their parents? Naturally many other questions arose as the work proceeded, but these were the main ones on which the project was initiated.
- Full Text:
- Date Issued: 1967
An investigation into the decametric radio emission by the planet Jupiter
- Authors: Gruber, Georg M
- Date: 1967
- Subjects: Jupiter (Planet) , Radio astronomy , Radio sources (Astronomy)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5545 , http://hdl.handle.net/10962/d1013410
- Description: From introduction: Jupiter is the largest planet in the solar system. Its distance from the Sun is five times that of the Earth and its mass is nearly two and a half times that of all the other planets added together. Jupiter turns about its own axis rather rapidly, once in just under ten hours, and it completes one revolution about the Sun in just under twelve years. Thus Earth has to pass almost directly between the Sun and Jupiter once every thirteen months. When this happens Jupiter is said to be in "opposition", as its position is then opposite to that of the Sun, when viewed from Earth. Around this time the planet will be most favourably placed for observations, as it is at its closest to Earth and up in the sky for a large part of the night. During the day observations on radio frequencies are more difficult, as the Sun is a source of great interference. Besides being an emitter of thermal electromagnetic radiation, as one would expect, Jupiter also emits two kinds of non-thermal radiation, one in the decimetre wavelength range and the other in the decametre wavelength range. A large number of scientists have worked on the problems of decimetre and decametre radiation. This thesis deals with some aspects of decametre radiation.
- Full Text:
- Date Issued: 1967
- Authors: Gruber, Georg M
- Date: 1967
- Subjects: Jupiter (Planet) , Radio astronomy , Radio sources (Astronomy)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5545 , http://hdl.handle.net/10962/d1013410
- Description: From introduction: Jupiter is the largest planet in the solar system. Its distance from the Sun is five times that of the Earth and its mass is nearly two and a half times that of all the other planets added together. Jupiter turns about its own axis rather rapidly, once in just under ten hours, and it completes one revolution about the Sun in just under twelve years. Thus Earth has to pass almost directly between the Sun and Jupiter once every thirteen months. When this happens Jupiter is said to be in "opposition", as its position is then opposite to that of the Sun, when viewed from Earth. Around this time the planet will be most favourably placed for observations, as it is at its closest to Earth and up in the sky for a large part of the night. During the day observations on radio frequencies are more difficult, as the Sun is a source of great interference. Besides being an emitter of thermal electromagnetic radiation, as one would expect, Jupiter also emits two kinds of non-thermal radiation, one in the decimetre wavelength range and the other in the decametre wavelength range. A large number of scientists have worked on the problems of decimetre and decametre radiation. This thesis deals with some aspects of decametre radiation.
- Full Text:
- Date Issued: 1967
Contributions to the ecology of the anomuran mud prawn Upogebia africana (Ortmann)
- Authors: Hill, Burke J
- Date: 1967
- Subjects: Decapoda , Shrimps
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5888 , http://hdl.handle.net/10962/d1013341
- Description: Estuarine ecology in South Africa has progressed in two distinct stages. The first of these was a necessary descriptive phase which documented the general distribution of estuarine animals and recorded the physical conditions within estuaries . This phase has been carried out by the Zoology Department of the University of Cape Town which has made a series of ecological surveys of southern African estuaries. These surveys have provided a vast amount of valuable information which was utilised by Day (1964.) to state some general conclusions about estuarine faunas. The most important of these conclusions is that most of the estuarine fauna is really a quiet water fauna which also occurs in sheltered non-estuarine water. The information gained in this first stage is necessarily general and it can only indicate overall trends or reveal major features of distribution. Further estuary surveys are not justified unless they deal with unique conditions. It is at this point that the second phase of estuarine ecology becomes necessary. This phase involves a detailed investigation of individual species or particular problems. The present investigation falls into this second stage of estuarine ecology and was designed to extend our knowledge of the anomuran mud prawn Upogebia africana (Ortmann). The general estuarine surveys have shown that U. africana is a common inhabitant of many estuaries and sheltered bays along the southern African coast from Langebaan on the West coast to Inhambane on the East coast. However these surveys only revealed and could not explain anomalies in its distribution such as its apparent absence from closed estuaries and from estuaries in the tropics. In addition it was not even certain whether this abundant and widespread animal should really be considered a valid species distinct from a common West Coast prawn Upogebia capensis (Krauss). It was felt that a study of an estuarine species should be based upon a sound knowledge of its distribution, population structure and habitat. Knowledge of the habitat must be gained by studies in the field to establish which facets of the environment are of importance to the species. It was decided on the basis of field observations that temperature and salinity are of prime importance: in limiting the distribution of U. africana and a detailed laboratory study was therefore made of the tolerance of U. africana to these two physical factors. The results of laboratory experiments together with field observations were finally used to interpret the ecology of the species. Most of present day knowledge of crustacean ecology has been gained from a study of European and North American animals and information about southern hemisphere species has lagged behind. It is hoped that the present study will contribute to a wider understanding of Crustacea and that it will lead to further more advanced research on South African marine and estuarine animals
- Full Text:
- Date Issued: 1967
- Authors: Hill, Burke J
- Date: 1967
- Subjects: Decapoda , Shrimps
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5888 , http://hdl.handle.net/10962/d1013341
- Description: Estuarine ecology in South Africa has progressed in two distinct stages. The first of these was a necessary descriptive phase which documented the general distribution of estuarine animals and recorded the physical conditions within estuaries . This phase has been carried out by the Zoology Department of the University of Cape Town which has made a series of ecological surveys of southern African estuaries. These surveys have provided a vast amount of valuable information which was utilised by Day (1964.) to state some general conclusions about estuarine faunas. The most important of these conclusions is that most of the estuarine fauna is really a quiet water fauna which also occurs in sheltered non-estuarine water. The information gained in this first stage is necessarily general and it can only indicate overall trends or reveal major features of distribution. Further estuary surveys are not justified unless they deal with unique conditions. It is at this point that the second phase of estuarine ecology becomes necessary. This phase involves a detailed investigation of individual species or particular problems. The present investigation falls into this second stage of estuarine ecology and was designed to extend our knowledge of the anomuran mud prawn Upogebia africana (Ortmann). The general estuarine surveys have shown that U. africana is a common inhabitant of many estuaries and sheltered bays along the southern African coast from Langebaan on the West coast to Inhambane on the East coast. However these surveys only revealed and could not explain anomalies in its distribution such as its apparent absence from closed estuaries and from estuaries in the tropics. In addition it was not even certain whether this abundant and widespread animal should really be considered a valid species distinct from a common West Coast prawn Upogebia capensis (Krauss). It was felt that a study of an estuarine species should be based upon a sound knowledge of its distribution, population structure and habitat. Knowledge of the habitat must be gained by studies in the field to establish which facets of the environment are of importance to the species. It was decided on the basis of field observations that temperature and salinity are of prime importance: in limiting the distribution of U. africana and a detailed laboratory study was therefore made of the tolerance of U. africana to these two physical factors. The results of laboratory experiments together with field observations were finally used to interpret the ecology of the species. Most of present day knowledge of crustacean ecology has been gained from a study of European and North American animals and information about southern hemisphere species has lagged behind. It is hoped that the present study will contribute to a wider understanding of Crustacea and that it will lead to further more advanced research on South African marine and estuarine animals
- Full Text:
- Date Issued: 1967
Hydrobiological studies on the Vaal River and some of its tributaries, including an introduction to the ecology of Simulium in its lower reaches
- Authors: Chutter, F M
- Date: 1967
- Subjects: Freshwater biology Freshwater animals Freshwater ecology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5841 , http://hdl.handle.net/10962/d1010499
- Description: The studies on the Vaal River and its tributaries presented here, were carried out for a variety of reasons. Prominent among them were several of immediate practical importance, such as the need to know the pollution status of waters which ultimately form the major supply for the Witwatersrand urban and industrial complex, and the need for background data on a stretch of the river which was to be insecticided to control a Simulium pest. However the results of such work can often be used for wider purposes. In this thesis they are used to examine the major factors thought to govern the distribution and abundance of the invertebrate Metazoa in the river. Introduction, p. 2-3.
- Full Text:
- Date Issued: 1967
- Authors: Chutter, F M
- Date: 1967
- Subjects: Freshwater biology Freshwater animals Freshwater ecology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5841 , http://hdl.handle.net/10962/d1010499
- Description: The studies on the Vaal River and its tributaries presented here, were carried out for a variety of reasons. Prominent among them were several of immediate practical importance, such as the need to know the pollution status of waters which ultimately form the major supply for the Witwatersrand urban and industrial complex, and the need for background data on a stretch of the river which was to be insecticided to control a Simulium pest. However the results of such work can often be used for wider purposes. In this thesis they are used to examine the major factors thought to govern the distribution and abundance of the invertebrate Metazoa in the river. Introduction, p. 2-3.
- Full Text:
- Date Issued: 1967
Synthesis of flavan-3, 4-diols, stereochemistry of novel biflavanols and new non-tannins from Acacia Mearnsii
- Authors: Saayman, Henry Martin
- Date: 1967
- Subjects: Tannins Acacia mearnsii Stereochemistry Wattles (Plants) Chemistry, Analytic
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4444 , http://hdl.handle.net/10962/d1007704
- Description: From Summary: The structural elucidation of condensed tannins, which are considered to consist of C₁₅-flavan units, presents certain difficulties. These tannins occur in extremely complex mixtures, and their isolation is complicated by their susceptibility to oxidative denaturation. Limitations in the formation of significant degradation products add to these problems. Since condensed tannins of black wattle bark yield anthocyanidins on treatment with mineral acids, they are considered to be proanthocyanidin in character. For this reason the initial approach to the investigation of the structures of condensed tannins was by way of the synthesis of novel 7-hydroxyflavan-3,4-diols having a low degree of hydroxyl substitution. Submission of these to modern physical techniques such as nuclear magnetic resonance (n.m.r.) spectroscopy would yield valuable data regarding the chemical shifts and coupling constants of heterocyclic and benzenoid protons which may be used for subsequent work on more highly hydroxylated diols, biflavanols and finally the condensed tannins themselves.
- Full Text:
- Date Issued: 1967
- Authors: Saayman, Henry Martin
- Date: 1967
- Subjects: Tannins Acacia mearnsii Stereochemistry Wattles (Plants) Chemistry, Analytic
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4444 , http://hdl.handle.net/10962/d1007704
- Description: From Summary: The structural elucidation of condensed tannins, which are considered to consist of C₁₅-flavan units, presents certain difficulties. These tannins occur in extremely complex mixtures, and their isolation is complicated by their susceptibility to oxidative denaturation. Limitations in the formation of significant degradation products add to these problems. Since condensed tannins of black wattle bark yield anthocyanidins on treatment with mineral acids, they are considered to be proanthocyanidin in character. For this reason the initial approach to the investigation of the structures of condensed tannins was by way of the synthesis of novel 7-hydroxyflavan-3,4-diols having a low degree of hydroxyl substitution. Submission of these to modern physical techniques such as nuclear magnetic resonance (n.m.r.) spectroscopy would yield valuable data regarding the chemical shifts and coupling constants of heterocyclic and benzenoid protons which may be used for subsequent work on more highly hydroxylated diols, biflavanols and finally the condensed tannins themselves.
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- Date Issued: 1967