The effect of varying heavy metal balances in the nutrient medium, on the growth and development of Aspergillus Sp. and Penicillium Sp.
- Authors: Breen, C M
- Date: 1965
- Subjects: Heavy metals -- Absorption and adsorption , Aspergillus -- Growth , Penicillium -- Growth , Fungi -- Nutrition
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4268 , http://hdl.handle.net/10962/d1014597
- Description: The study was conducted to investigate the effects of: (i) varying the level of supply of the heavy metals iron, manganese, copper and zinc. (ii) varying the ratio between different pairs of metals in the medium. In particular the iron:manganese and zinc:copper ratios were studied. Initially the two fungi Aspergillus niger van Tieghem, (variety and strain) and Penicillium notatum Westling, were used. Penicillium notatum Westling was subsequently discarded, in favour of Penicillium glancum Link, because it did not sporulate freely in liquid culture. The fungi were grown in controlled nutrient solutions, and during the course of tho growth and development, the form and sporulation of the felts was noted. After a period of growth, the felts were removed, dried and weighed. The pH of the liquor was measured. the results were studied to determine the effect of varying levels of supply of the heavy metals, and of the varying heavy metal ratios in the culture solution. In the investigation of the effect of varying the level of supply of individual heavy metals, optimum concentrations were demonstrated for copper and manganese. Increaning the concentration of pairs of heavy metals cimultaneously was found to influence the appearance and degree of symptoms of toxicity. Cultures of Aspergillus and Penicillium were found to be able to tolerate concentrations of copper, in particular, considerably greater than the observed optima, when zinc was present in equal concentration. Citric acid, and subsequently ethylene- diaminetetra-acetic acid, were used as chelating agents, in order to prevent the precipitation of the metals in the culture solution during autoclaving. It was found that the use of chelating agents markedly reduced symptoms of toxicity. There was no conclusive evidence that the iron:manganese ratio in the culture medium was an important factor in the growth and development of cultures of Aspergillus and Penicillium. However there is considerable evidence that in cultures of Penicillium, the zinc:copper ratio in the medium is of some importance in the determination of the dry weight yield trends. This effect was not demonstrated in cultures of Aspergillus.
- Full Text:
- Date Issued: 1965
- Authors: Breen, C M
- Date: 1965
- Subjects: Heavy metals -- Absorption and adsorption , Aspergillus -- Growth , Penicillium -- Growth , Fungi -- Nutrition
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4268 , http://hdl.handle.net/10962/d1014597
- Description: The study was conducted to investigate the effects of: (i) varying the level of supply of the heavy metals iron, manganese, copper and zinc. (ii) varying the ratio between different pairs of metals in the medium. In particular the iron:manganese and zinc:copper ratios were studied. Initially the two fungi Aspergillus niger van Tieghem, (variety and strain) and Penicillium notatum Westling, were used. Penicillium notatum Westling was subsequently discarded, in favour of Penicillium glancum Link, because it did not sporulate freely in liquid culture. The fungi were grown in controlled nutrient solutions, and during the course of tho growth and development, the form and sporulation of the felts was noted. After a period of growth, the felts were removed, dried and weighed. The pH of the liquor was measured. the results were studied to determine the effect of varying levels of supply of the heavy metals, and of the varying heavy metal ratios in the culture solution. In the investigation of the effect of varying the level of supply of individual heavy metals, optimum concentrations were demonstrated for copper and manganese. Increaning the concentration of pairs of heavy metals cimultaneously was found to influence the appearance and degree of symptoms of toxicity. Cultures of Aspergillus and Penicillium were found to be able to tolerate concentrations of copper, in particular, considerably greater than the observed optima, when zinc was present in equal concentration. Citric acid, and subsequently ethylene- diaminetetra-acetic acid, were used as chelating agents, in order to prevent the precipitation of the metals in the culture solution during autoclaving. It was found that the use of chelating agents markedly reduced symptoms of toxicity. There was no conclusive evidence that the iron:manganese ratio in the culture medium was an important factor in the growth and development of cultures of Aspergillus and Penicillium. However there is considerable evidence that in cultures of Penicillium, the zinc:copper ratio in the medium is of some importance in the determination of the dry weight yield trends. This effect was not demonstrated in cultures of Aspergillus.
- Full Text:
- Date Issued: 1965
The emotive qualities of light as a prime factor in artistic expression
- Authors: Brooks, R B
- Date: 1965
- Subjects: Light in art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2502 , http://hdl.handle.net/10962/d1014659
- Description: What we do possess to-day as 'art' a faked music, filled with exotic and showcard effects, that every ten years or so concocted out of the form-wealth of millenia some new "style'' which is no style at all since everyone does as he pleases. A lying plastic that steals from Assyria, Egypt and Mexico indifferently. Yet this and only this, the taste of the "man of the world" can be accepted as the expression and sign of the age. Everything else, everything that sticks to old ideals is for provincial consumption. This is the year 1965 - nearly fifty years since Oswald Spengler published "The decline of the West" The paragraph I have quoted by way of justification for this dissertation is in turn a justiification of the fact that Spengler is as valid today as he was in 1918.
- Full Text:
- Date Issued: 1965
- Authors: Brooks, R B
- Date: 1965
- Subjects: Light in art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2502 , http://hdl.handle.net/10962/d1014659
- Description: What we do possess to-day as 'art' a faked music, filled with exotic and showcard effects, that every ten years or so concocted out of the form-wealth of millenia some new "style'' which is no style at all since everyone does as he pleases. A lying plastic that steals from Assyria, Egypt and Mexico indifferently. Yet this and only this, the taste of the "man of the world" can be accepted as the expression and sign of the age. Everything else, everything that sticks to old ideals is for provincial consumption. This is the year 1965 - nearly fifty years since Oswald Spengler published "The decline of the West" The paragraph I have quoted by way of justification for this dissertation is in turn a justiification of the fact that Spengler is as valid today as he was in 1918.
- Full Text:
- Date Issued: 1965
The geology of a portion of south-western Albany
- Meyer, W
- Authors: Meyer, W
- Date: 1965
- Subjects: Geology -- South Africa -- Eastern Cape , Silcrete , Geology, Stratigraphic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5065 , http://hdl.handle.net/10962/d1013371
- Description: During 1963 an area was mapped around Sidbury, 23 miles south- west of Grahamstown. The object of the survey was to examine stratigraphic problems, which included the nature of a large occurrence of shale south of Alicedale in a region previously mapped as Witteberg, and the relationship between Silcrete and Calcrete. During the invest igation evidence of the existence of two, possibly three , major thrust-faults and of extensive overfolding to the south was discovered. There is reason to believe, that movement on the Zuurberg Fault was initiated in pre-Cretaceous times, and renewed in the early Cretaceous. The Silcrete is shown to be related to the pattern of presentday drainage. Stone implements found embedded in the Calcrete suggest that it is of Recent age.
- Full Text:
- Date Issued: 1965
- Authors: Meyer, W
- Date: 1965
- Subjects: Geology -- South Africa -- Eastern Cape , Silcrete , Geology, Stratigraphic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5065 , http://hdl.handle.net/10962/d1013371
- Description: During 1963 an area was mapped around Sidbury, 23 miles south- west of Grahamstown. The object of the survey was to examine stratigraphic problems, which included the nature of a large occurrence of shale south of Alicedale in a region previously mapped as Witteberg, and the relationship between Silcrete and Calcrete. During the invest igation evidence of the existence of two, possibly three , major thrust-faults and of extensive overfolding to the south was discovered. There is reason to believe, that movement on the Zuurberg Fault was initiated in pre-Cretaceous times, and renewed in the early Cretaceous. The Silcrete is shown to be related to the pattern of presentday drainage. Stone implements found embedded in the Calcrete suggest that it is of Recent age.
- Full Text:
- Date Issued: 1965
The reminiscences of Thomas Stubbs, 1820 - 1877
- Authors: McGeoch, Robert Thomas
- Date: 1965
- Subjects: Stubbs family , British settlers of 1820 (South Africa) -- Personal narratives , South Africa -- History -- Frontier Wars, 1811-1878 , Cape of Good Hope (South Africa) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2609 , http://hdl.handle.net/10962/d1012851
- Description: The "Reminiscences" of Thomas Stubbs are one of several such compositions which have survived from the 1820 Settlers. The manuscript offers one of the fullest and most lively accounts of frontier life, and the experiences of the Settlers as seen through the eyes of Thomas Stubbs. The object of this thesis has been to reconstruct the life of Thomas Stubbs which has proved an arduous yet absorbing task and to comment upon and evaluate some of the views Stubbs expressed when he wrote the "Reminiscences" between 1874 and 1875, as well as to test, where possible, the validity of the opinions and sentiments formed during a half-century's acquaintance with the Eastern frontier of the Cape of Good Hope.
- Full Text:
- Date Issued: 1965
- Authors: McGeoch, Robert Thomas
- Date: 1965
- Subjects: Stubbs family , British settlers of 1820 (South Africa) -- Personal narratives , South Africa -- History -- Frontier Wars, 1811-1878 , Cape of Good Hope (South Africa) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2609 , http://hdl.handle.net/10962/d1012851
- Description: The "Reminiscences" of Thomas Stubbs are one of several such compositions which have survived from the 1820 Settlers. The manuscript offers one of the fullest and most lively accounts of frontier life, and the experiences of the Settlers as seen through the eyes of Thomas Stubbs. The object of this thesis has been to reconstruct the life of Thomas Stubbs which has proved an arduous yet absorbing task and to comment upon and evaluate some of the views Stubbs expressed when he wrote the "Reminiscences" between 1874 and 1875, as well as to test, where possible, the validity of the opinions and sentiments formed during a half-century's acquaintance with the Eastern frontier of the Cape of Good Hope.
- Full Text:
- Date Issued: 1965
An investigation of the role of conflict in the stratificationary process of the African in the copper mining industry of Northern Rhodesia between the years, 1943-1961
- Authors: Coetzee, J A G
- Date: 1964
- Subjects: Social conflict -- Zambia , Conflict management -- Zambia , Copper industry and trade -- Zambia
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3382 , http://hdl.handle.net/10962/d1013332
- Description: The aim of this study is to investigate the role of CONFLICT in the stratificationary process of the African in the Copper Mining Industry of Northern Rhodesia between the years 1943 - 1961. The hypothesis and assumptions which it is desired to prove can be classified as falling into four categories: 1. that which accepts human beings as individuals acting in group structures, each group having its appropriate goals and ends forming discernable patterned action systems; 2. that these groups can be reconstructed to show variable patterns of action which might be either accommodative or initially contradictory as conflicts emerge within the system; 3. that items 1 and 2 above can be objectivised by empirical materials and that they change in time, and, in so doing, are modified in structure-functional relations; 4. that conflict is the process which animates the patterns and prescribes new goals and ends within the patterned activity systems. An indefinite number of causality factors are possible in explaining social change, but we confine ourselves to the concept CONFLICT, with special reference to the Copperbelt of Northern Rhodesia. The economic factors operating, together with the political and social factors, producing a typical stratification of the African in the industry, sofar as this reveals changing patterns of progressive and aggressive goal thrusts and redefinition of the social positions of the contesting participants, are dealt with in the appropriate sections of this investigation. The model has been developed in relation to the study of the total social system with special emphasis on their overtly political and economical aspects. Part 1, in its entirety, deals with the theory of conflict. It also contains our own development of the theme. The empirical data are contained in parts 2, 3, with a section on envisaged future social developments. The conclusion, to this investigation, forms the last part , with an exhaustive testing of the TEN-POINT HYPOTHESIS given at the end of Part 1.
- Full Text:
- Date Issued: 1964
- Authors: Coetzee, J A G
- Date: 1964
- Subjects: Social conflict -- Zambia , Conflict management -- Zambia , Copper industry and trade -- Zambia
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3382 , http://hdl.handle.net/10962/d1013332
- Description: The aim of this study is to investigate the role of CONFLICT in the stratificationary process of the African in the Copper Mining Industry of Northern Rhodesia between the years 1943 - 1961. The hypothesis and assumptions which it is desired to prove can be classified as falling into four categories: 1. that which accepts human beings as individuals acting in group structures, each group having its appropriate goals and ends forming discernable patterned action systems; 2. that these groups can be reconstructed to show variable patterns of action which might be either accommodative or initially contradictory as conflicts emerge within the system; 3. that items 1 and 2 above can be objectivised by empirical materials and that they change in time, and, in so doing, are modified in structure-functional relations; 4. that conflict is the process which animates the patterns and prescribes new goals and ends within the patterned activity systems. An indefinite number of causality factors are possible in explaining social change, but we confine ourselves to the concept CONFLICT, with special reference to the Copperbelt of Northern Rhodesia. The economic factors operating, together with the political and social factors, producing a typical stratification of the African in the industry, sofar as this reveals changing patterns of progressive and aggressive goal thrusts and redefinition of the social positions of the contesting participants, are dealt with in the appropriate sections of this investigation. The model has been developed in relation to the study of the total social system with special emphasis on their overtly political and economical aspects. Part 1, in its entirety, deals with the theory of conflict. It also contains our own development of the theme. The empirical data are contained in parts 2, 3, with a section on envisaged future social developments. The conclusion, to this investigation, forms the last part , with an exhaustive testing of the TEN-POINT HYPOTHESIS given at the end of Part 1.
- Full Text:
- Date Issued: 1964
Industrial development in a border area: facts and figures from East London
- Authors: Barker, John Percy
- Date: 1964
- Subjects: Industrialization , East London (South Africa) -- Industries
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1078 , http://hdl.handle.net/10962/d1009504 , Industrialization , East London (South Africa) -- Industries
- Description: In the early 1950's the area of the eastern Cape Province adjoining the Transkei was the object of an intensive study known as the Border Regional Survey and five volumes have already been published. This work is a more detailed investigation of one aspect of the economy, namely the growth of manufacturing industry. Its importance lies in the fact that not only is the African population increasing rapidly, but that effective rehabilitation of peasant farming in the Transkei and Ciskei must necessarily displace large numbers from the land. Expansion of manufacturing industry would appear to be the most effective means of providing remunerative employment for these people. Moreover, the government has embarked upon a policy of encouraging the establishment of factories on the periphery of the Bantu areas, and the eastern Cape is an important area in this general scheme. It may well be the most crucial testing point of the whole policy of 'border industries', because with its large Transkeian hinterland it is the area most in need of expanding employment opportunities; but, at the same time, by reason of locational and other disabilities, it is the area in which industrial expansion may be most difficult to achieve.
- Full Text:
- Date Issued: 1964
- Authors: Barker, John Percy
- Date: 1964
- Subjects: Industrialization , East London (South Africa) -- Industries
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1078 , http://hdl.handle.net/10962/d1009504 , Industrialization , East London (South Africa) -- Industries
- Description: In the early 1950's the area of the eastern Cape Province adjoining the Transkei was the object of an intensive study known as the Border Regional Survey and five volumes have already been published. This work is a more detailed investigation of one aspect of the economy, namely the growth of manufacturing industry. Its importance lies in the fact that not only is the African population increasing rapidly, but that effective rehabilitation of peasant farming in the Transkei and Ciskei must necessarily displace large numbers from the land. Expansion of manufacturing industry would appear to be the most effective means of providing remunerative employment for these people. Moreover, the government has embarked upon a policy of encouraging the establishment of factories on the periphery of the Bantu areas, and the eastern Cape is an important area in this general scheme. It may well be the most crucial testing point of the whole policy of 'border industries', because with its large Transkeian hinterland it is the area most in need of expanding employment opportunities; but, at the same time, by reason of locational and other disabilities, it is the area in which industrial expansion may be most difficult to achieve.
- Full Text:
- Date Issued: 1964
Some aspects of the ecology and biology of two estuarine grapsoid crabs
- Authors: Warren, Stephanie Judith
- Date: 1964
- Subjects: Crabs -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5899 , http://hdl.handle.net/10962/d1013506
- Description: Extracted from Summary, p. 172. The semi-terrestrial grapsoid crabs Cyclograpsus punctatus and Sesarma catenata have been studied in two ways. Part I of this thesis gives an account of their distribution in the Kowie River estuary in relation to certain environmental factors. Part II deals with further aspects of their biology as well as the ecological relationship between the two species.
- Full Text:
- Date Issued: 1964
- Authors: Warren, Stephanie Judith
- Date: 1964
- Subjects: Crabs -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5899 , http://hdl.handle.net/10962/d1013506
- Description: Extracted from Summary, p. 172. The semi-terrestrial grapsoid crabs Cyclograpsus punctatus and Sesarma catenata have been studied in two ways. Part I of this thesis gives an account of their distribution in the Kowie River estuary in relation to certain environmental factors. Part II deals with further aspects of their biology as well as the ecological relationship between the two species.
- Full Text:
- Date Issued: 1964
Some ionospheric effects observed at sunrise
- Authors: Baker, D C
- Date: 1964
- Subjects: Sun -- Rising and setting , Ionosphere -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5513 , http://hdl.handle.net/10962/d1009496 , Sun -- Rising and setting , Ionosphere -- Research
- Description: The study of the ionosphere over the sunrise period is necessary for an understanding of the vtiriations in layer structure with time and has been a topic of research of many workers. On the whole these investigations have been restricted to a study of critical frequency variations with relatively short intervals of a few minutes between successive records, of N-h curves deduced from ionograms with long intervals (15 minutes or so) between successive N-h curves or of continuously monitored single frequency reflections. Not one of the three techniques is entirely satisfactory for a detailed study of ionospheric behaviour over sunrise. The first two do not give a sufficiently clear indication of what happens in the initial stages of layer development, while from the third incomplete data is obtained as to what is happening at a specific electron-density level. For this reason a preliminary investigation of the ionosphere over sunrise was made at Rhodes University during August, 1959. The records were obtained at four-and-a-half minute intervals and scaled by the method of KELSO (1952 ). "Many of t he results were inconclusive but it appeared that records would have to be taken at approximately one minute intervals and reduced to N-h curves by a scaling technique which made full allowance for low-level ionization if useful results were to be obtained. An attempt has been made in this thesis to investigate the behaviour of the ionosphere over sunrise more fully than can be done by the three techniques referred to. A number of observed phenomena are also examined. Part I deals with the theoretical background to ionosphere physics in general and describes the equipment, equipment modifications and experimental procedure. Part II presents the results obtained. The records for a largescale travelling disturbance are analysed. Various observed phenomena are described and discussed. A simple method of obtaining production rates from experimental data is described. The implications of the observed variations of production rates with height and time are discussed. Suggestions for further research and improvement of the methods used arc made in Charter 9.
- Full Text:
- Date Issued: 1964
- Authors: Baker, D C
- Date: 1964
- Subjects: Sun -- Rising and setting , Ionosphere -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5513 , http://hdl.handle.net/10962/d1009496 , Sun -- Rising and setting , Ionosphere -- Research
- Description: The study of the ionosphere over the sunrise period is necessary for an understanding of the vtiriations in layer structure with time and has been a topic of research of many workers. On the whole these investigations have been restricted to a study of critical frequency variations with relatively short intervals of a few minutes between successive records, of N-h curves deduced from ionograms with long intervals (15 minutes or so) between successive N-h curves or of continuously monitored single frequency reflections. Not one of the three techniques is entirely satisfactory for a detailed study of ionospheric behaviour over sunrise. The first two do not give a sufficiently clear indication of what happens in the initial stages of layer development, while from the third incomplete data is obtained as to what is happening at a specific electron-density level. For this reason a preliminary investigation of the ionosphere over sunrise was made at Rhodes University during August, 1959. The records were obtained at four-and-a-half minute intervals and scaled by the method of KELSO (1952 ). "Many of t he results were inconclusive but it appeared that records would have to be taken at approximately one minute intervals and reduced to N-h curves by a scaling technique which made full allowance for low-level ionization if useful results were to be obtained. An attempt has been made in this thesis to investigate the behaviour of the ionosphere over sunrise more fully than can be done by the three techniques referred to. A number of observed phenomena are also examined. Part I deals with the theoretical background to ionosphere physics in general and describes the equipment, equipment modifications and experimental procedure. Part II presents the results obtained. The records for a largescale travelling disturbance are analysed. Various observed phenomena are described and discussed. A simple method of obtaining production rates from experimental data is described. The implications of the observed variations of production rates with height and time are discussed. Suggestions for further research and improvement of the methods used arc made in Charter 9.
- Full Text:
- Date Issued: 1964
The north gap dyke of the Transkei
- Authors: Moore, Alan C
- Date: 1964
- Subjects: Petrology -- South Africa -- Transkei , Dikes (Geology) -- South Africa -- Transkei , Petrofabric analysis -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5031 , http://hdl.handle.net/10962/d1007087
- Description: Field work and mapping with the aid of aerial photographs have shown the north Gap Dyke to be a vertical intrusion 93½ miles long . It extends from a point about 4½ miles south of Cathcart to the coast where it enters the sea about 100 yards north of the Ngadla R lver mouth. It is composed of several rock types including dolerite pegmatite, granophyric dolerite, subophitic dolerite, and it has a more or less central core of mobilized sediment at the western end. The essential minerals of the dolerite types include zoned plagioclase, which is described in some detail, and augite. Less important are hornblende and micropegmatite. Accessories include apatite, ilmenite, magnetite, quartz, actinolite, prehnite, calcite and epidote. Iddingsite (?), saussurite and chlorite occur as alteration products. The mode of origin of the Gap Dyke magma remains an open question: it may have arisen as a result of normal crystal fractionation or as the result of hybridization in depth followed by differentiation.
- Full Text:
- Date Issued: 1964
- Authors: Moore, Alan C
- Date: 1964
- Subjects: Petrology -- South Africa -- Transkei , Dikes (Geology) -- South Africa -- Transkei , Petrofabric analysis -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5031 , http://hdl.handle.net/10962/d1007087
- Description: Field work and mapping with the aid of aerial photographs have shown the north Gap Dyke to be a vertical intrusion 93½ miles long . It extends from a point about 4½ miles south of Cathcart to the coast where it enters the sea about 100 yards north of the Ngadla R lver mouth. It is composed of several rock types including dolerite pegmatite, granophyric dolerite, subophitic dolerite, and it has a more or less central core of mobilized sediment at the western end. The essential minerals of the dolerite types include zoned plagioclase, which is described in some detail, and augite. Less important are hornblende and micropegmatite. Accessories include apatite, ilmenite, magnetite, quartz, actinolite, prehnite, calcite and epidote. Iddingsite (?), saussurite and chlorite occur as alteration products. The mode of origin of the Gap Dyke magma remains an open question: it may have arisen as a result of normal crystal fractionation or as the result of hybridization in depth followed by differentiation.
- Full Text:
- Date Issued: 1964
The South Atlantic radiation anomaly
- Authors: Van Rooyen, H O
- Date: 1964
- Subjects: Terrestrial radiation , Atmospheric radiation , Geomagnetism , Electron precipitation , South Atlantic Ocean -- Radiation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5546 , http://hdl.handle.net/10962/d1013427
- Description: Part I. (1) An elementary treatment of the motion of charged particles in a magnetic field is presented. The concept of guiding centre motion is introduced, and is used in outlining the theory of particle drifts. (2 ) The motion of charged particles in the geomagnetic field is discussed, and the concept of adiabatic invariance introduced. (3) Mc Iliwains coordinates for mapping the distribution of charged particles trapped in the geometric field are defined and briefly discussed. (4) A survey of present knowledge of the Van Allen radiation zones is made. Particular attention is given to the distribution, characteristics, and variability of the trapped radiation. (5) The Cape Town magnetic anomaly, the Brazil radiation anomaly and the South Atlantic radiation anomaly are discussed. The electrons entering the South Atlantic radiation anomaly are shown to be those monitored over Iowa by the US satellite Injun I. Part 11. (1) It is shown how the geomagnetic field can, at high altitudes and over relatively short distances, be approximated by the field of a monopole. A new method is developed which enables one to plot the energy absorbed from an electron (which moves in a monopole field in the atmosphere) against altitude, given the initial energy and pitch angle of the electron. Some numerical computations using this method are described, and the results discussed. These results are used, in conjunction with US satellite Injun I for the Iowa region, to estimate the energy inout to the atmosphere in the South Atlantic radiation anomaly. The main approximations and simplifying assumptions made in this treatment, are discussed. (2) Geophysical effects generally recognized to be connected with the precipitation of charged particles are discussed. In the course of this discussion the two main theories of the connection between the radiation zones and the auroras are examined. (3) A preliminary discussion, based on the work summarized in point (1) of detectable geophysical events associated with the precipitation of electrons into the South Atlantic radiation anomaly is given. It is concluded that auroral emission, X-ray bursts, and ionospheric ionization in the E region should be more frequent and pronounced in the South Atlantic radiation anomaly than in any other region of comparable invariant latitudes and that the effects of atmospheric heating by precipitated electrons should be detectable over the anomaly. (4) An assessment is made of the value of the method referred to in point (1). Suggestions for its modification and extension are put forward. It is suggested that if more extensive rocket and satellite data on the low energy component of the electron flux become available, this method can be employed in a rigorous theoretical investigation of the South Atlantic radiation anomaly. Summary, p. 98-100.
- Full Text:
- Date Issued: 1964
- Authors: Van Rooyen, H O
- Date: 1964
- Subjects: Terrestrial radiation , Atmospheric radiation , Geomagnetism , Electron precipitation , South Atlantic Ocean -- Radiation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5546 , http://hdl.handle.net/10962/d1013427
- Description: Part I. (1) An elementary treatment of the motion of charged particles in a magnetic field is presented. The concept of guiding centre motion is introduced, and is used in outlining the theory of particle drifts. (2 ) The motion of charged particles in the geomagnetic field is discussed, and the concept of adiabatic invariance introduced. (3) Mc Iliwains coordinates for mapping the distribution of charged particles trapped in the geometric field are defined and briefly discussed. (4) A survey of present knowledge of the Van Allen radiation zones is made. Particular attention is given to the distribution, characteristics, and variability of the trapped radiation. (5) The Cape Town magnetic anomaly, the Brazil radiation anomaly and the South Atlantic radiation anomaly are discussed. The electrons entering the South Atlantic radiation anomaly are shown to be those monitored over Iowa by the US satellite Injun I. Part 11. (1) It is shown how the geomagnetic field can, at high altitudes and over relatively short distances, be approximated by the field of a monopole. A new method is developed which enables one to plot the energy absorbed from an electron (which moves in a monopole field in the atmosphere) against altitude, given the initial energy and pitch angle of the electron. Some numerical computations using this method are described, and the results discussed. These results are used, in conjunction with US satellite Injun I for the Iowa region, to estimate the energy inout to the atmosphere in the South Atlantic radiation anomaly. The main approximations and simplifying assumptions made in this treatment, are discussed. (2) Geophysical effects generally recognized to be connected with the precipitation of charged particles are discussed. In the course of this discussion the two main theories of the connection between the radiation zones and the auroras are examined. (3) A preliminary discussion, based on the work summarized in point (1) of detectable geophysical events associated with the precipitation of electrons into the South Atlantic radiation anomaly is given. It is concluded that auroral emission, X-ray bursts, and ionospheric ionization in the E region should be more frequent and pronounced in the South Atlantic radiation anomaly than in any other region of comparable invariant latitudes and that the effects of atmospheric heating by precipitated electrons should be detectable over the anomaly. (4) An assessment is made of the value of the method referred to in point (1). Suggestions for its modification and extension are put forward. It is suggested that if more extensive rocket and satellite data on the low energy component of the electron flux become available, this method can be employed in a rigorous theoretical investigation of the South Atlantic radiation anomaly. Summary, p. 98-100.
- Full Text:
- Date Issued: 1964
The use of certain myths in the work of T.S. Eliot
- Authors: Hall, R F
- Date: 1964
- Subjects: Eliot, T. S. (Thomas Stearns), 1888-1965 -- Knowledge -- Literature , Eliot, T. S. (Thomas Stearns), 1888-1965 -- Criticism and interpretation , Mythology in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2300 , http://hdl.handle.net/10962/d1012129 , Eliot, T. S. (Thomas Stearns), 1888-1965 -- Knowledge -- Literature , Eliot, T. S. (Thomas Stearns), 1888-1965 -- Criticism and interpretation , Mythology in literature
- Description: T.S. Eliot's statement that myth is an ordering device in literature 'is constantly belied by his use of myth in his own poems'. This is the belief of the American critic Richard Chase, noted for his work on myths and mythological themes in English and American literature. Whether or not Chase is right must emerge from the chapters which follow. The purpose will be to examine the effects of the use of myths and mythological patterns on Eliot's work in general, rather than to annotate individual mythological allusions. Simply to recognise an allusion is to raise a question, not to answer one: for we have then to decide what the writer hope to achieve by its use, and whether or not he has succeeded. Unless they lead on to such questions, lists of sources contribute little to our understanding of a work. Far more important than incidental allusions are the mythological themes and patterns on the larger scale, which reveal themselves in recurrent allusions and in basic patterns of symbolism. Again, merely to recognise such a pattern is inadequate: in every case a discovery of its function in both the poem's (or play's) structure and the poet's technique should be our main concern. ... Eliot himself has made it clear that in his case the use of myths and mythological patterns has often been a fully conscious, even self-conscious process. Therefore we may apply to his work the questions mention by Norman: what functions the myths fulfil within individual works; and why Eliot uses them in the first place. This last question leads us back to a more fundamental one; why do many writers, especially modern ones, use myths 'in the first place'? The problem involves discussion of the relation between myths and literature and of the nature of myths themselves, this forms the material of the first chapter. The other chapters will deal with some of Eliot's works, attempting to explain and analyse his use of myths in them, and to illustrate its importance in each case.
- Full Text:
- Date Issued: 1964
- Authors: Hall, R F
- Date: 1964
- Subjects: Eliot, T. S. (Thomas Stearns), 1888-1965 -- Knowledge -- Literature , Eliot, T. S. (Thomas Stearns), 1888-1965 -- Criticism and interpretation , Mythology in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2300 , http://hdl.handle.net/10962/d1012129 , Eliot, T. S. (Thomas Stearns), 1888-1965 -- Knowledge -- Literature , Eliot, T. S. (Thomas Stearns), 1888-1965 -- Criticism and interpretation , Mythology in literature
- Description: T.S. Eliot's statement that myth is an ordering device in literature 'is constantly belied by his use of myth in his own poems'. This is the belief of the American critic Richard Chase, noted for his work on myths and mythological themes in English and American literature. Whether or not Chase is right must emerge from the chapters which follow. The purpose will be to examine the effects of the use of myths and mythological patterns on Eliot's work in general, rather than to annotate individual mythological allusions. Simply to recognise an allusion is to raise a question, not to answer one: for we have then to decide what the writer hope to achieve by its use, and whether or not he has succeeded. Unless they lead on to such questions, lists of sources contribute little to our understanding of a work. Far more important than incidental allusions are the mythological themes and patterns on the larger scale, which reveal themselves in recurrent allusions and in basic patterns of symbolism. Again, merely to recognise such a pattern is inadequate: in every case a discovery of its function in both the poem's (or play's) structure and the poet's technique should be our main concern. ... Eliot himself has made it clear that in his case the use of myths and mythological patterns has often been a fully conscious, even self-conscious process. Therefore we may apply to his work the questions mention by Norman: what functions the myths fulfil within individual works; and why Eliot uses them in the first place. This last question leads us back to a more fundamental one; why do many writers, especially modern ones, use myths 'in the first place'? The problem involves discussion of the relation between myths and literature and of the nature of myths themselves, this forms the material of the first chapter. The other chapters will deal with some of Eliot's works, attempting to explain and analyse his use of myths in them, and to illustrate its importance in each case.
- Full Text:
- Date Issued: 1964
An investigation into the spelling ability of English-speaking and Afrikaans-speaking pupils in South African schools
- Authors: Hayward, Fritz Reitz
- Date: 1963
- Subjects: English language -- Orthography and spelling -- Study and teaching , Afrikaans language -- Orthography and spelling -- Study and teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1972 , http://hdl.handle.net/10962/d1012238 , English language -- Orthography and spelling -- Study and teaching , Afrikaans language -- Orthography and spelling -- Study and teaching
- Description: The parlous state in which the English language finds itself in South Africa, both in its written and speech forms, is the cause ot grave concern to most English-speaking citizens, and to many Afrikaans-speaking people as well. This is the case not only in the commercial world and the civll service, but also in the schools and universities, and in fact in most walks of life. Although we are conscious of this state of affairs, and can quote many examples of the poor quality of English used, we have no measuring device through which we can assess exactly how bad the language used by any given group of people is. It is not possible to compare the performance in English of a certain school with standard English and to express the result as a percentage score. The aim of this investigation was to find out how well, or how badly, South African school children spell, and to compare the performances of English- and Afrikaansspeaking pupils. It was felt that the results would provide some concrete evidence and fairly accurate data which could be used to assess the standard of English spelling in our schools, and to pinpoint some of the major weaknesses. The writer hoped, thus, that the investigation might be of some practical usefulness to teachers of English spelling, and as spelling is basic to the written word and to some extent to the spoken word, it might make some small contribution to the drive towards better English in South African schools.
- Full Text:
- Date Issued: 1963
- Authors: Hayward, Fritz Reitz
- Date: 1963
- Subjects: English language -- Orthography and spelling -- Study and teaching , Afrikaans language -- Orthography and spelling -- Study and teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1972 , http://hdl.handle.net/10962/d1012238 , English language -- Orthography and spelling -- Study and teaching , Afrikaans language -- Orthography and spelling -- Study and teaching
- Description: The parlous state in which the English language finds itself in South Africa, both in its written and speech forms, is the cause ot grave concern to most English-speaking citizens, and to many Afrikaans-speaking people as well. This is the case not only in the commercial world and the civll service, but also in the schools and universities, and in fact in most walks of life. Although we are conscious of this state of affairs, and can quote many examples of the poor quality of English used, we have no measuring device through which we can assess exactly how bad the language used by any given group of people is. It is not possible to compare the performance in English of a certain school with standard English and to express the result as a percentage score. The aim of this investigation was to find out how well, or how badly, South African school children spell, and to compare the performances of English- and Afrikaansspeaking pupils. It was felt that the results would provide some concrete evidence and fairly accurate data which could be used to assess the standard of English spelling in our schools, and to pinpoint some of the major weaknesses. The writer hoped, thus, that the investigation might be of some practical usefulness to teachers of English spelling, and as spelling is basic to the written word and to some extent to the spoken word, it might make some small contribution to the drive towards better English in South African schools.
- Full Text:
- Date Issued: 1963
An investigation of the radio emission by the planet Jupiter on 18 Mc/s & 22 Mc/s
- Authors: Gruber, Georg Maria
- Date: 1963
- Subjects: Radio astronomy , Jupiter (Planet) -- Observations , Radio sources (Astronomy)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5524 , http://hdl.handle.net/10962/d1012113 , Radio astronomy , Jupiter (Planet) -- Observations , Radio sources (Astronomy)
- Description: This thesis describes the investigation carried out of the radio noise emitted by the planet Jupiter on 18 Mc/s and 22 Mc/s. Chapter I gives a brief introduction and outlines radioastronomical as well as astronomical ideas concerning Jupiter. A detailed survey of the research done to date including some of the hypotheses formulated by previous workers is presented in Chapter II . Chapter III deals with the apparatus used in this research. Two similar sets of apparatus were used. The aerials were folded dipoles. The signals were fed to the receiver, an R 206 , via a 300 ohm impedance line. To increase the gain an extra I -F. stage was included. This gave a gain of better than a 120 dB. To match the signals into the recorder a cathode follower was used. The operating procedure appears in the fourth chapter. The results obtained are discussed and tabulated at the end of the chapter. They agree with the findings made by previous workers, within the experimental limit. Histograms of the occurrence probability versus the revised System III coordinates are presented for each frequency and compared to previous ones. The final chapter contains the author ' s interpretation of the observed effects. A model based on a radiation analogous to the Cerenkov effect is found to be not inconsistent with the available data . Ending the chapter suggestions for further research are made.
- Full Text:
- Date Issued: 1963
- Authors: Gruber, Georg Maria
- Date: 1963
- Subjects: Radio astronomy , Jupiter (Planet) -- Observations , Radio sources (Astronomy)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5524 , http://hdl.handle.net/10962/d1012113 , Radio astronomy , Jupiter (Planet) -- Observations , Radio sources (Astronomy)
- Description: This thesis describes the investigation carried out of the radio noise emitted by the planet Jupiter on 18 Mc/s and 22 Mc/s. Chapter I gives a brief introduction and outlines radioastronomical as well as astronomical ideas concerning Jupiter. A detailed survey of the research done to date including some of the hypotheses formulated by previous workers is presented in Chapter II . Chapter III deals with the apparatus used in this research. Two similar sets of apparatus were used. The aerials were folded dipoles. The signals were fed to the receiver, an R 206 , via a 300 ohm impedance line. To increase the gain an extra I -F. stage was included. This gave a gain of better than a 120 dB. To match the signals into the recorder a cathode follower was used. The operating procedure appears in the fourth chapter. The results obtained are discussed and tabulated at the end of the chapter. They agree with the findings made by previous workers, within the experimental limit. Histograms of the occurrence probability versus the revised System III coordinates are presented for each frequency and compared to previous ones. The final chapter contains the author ' s interpretation of the observed effects. A model based on a radiation analogous to the Cerenkov effect is found to be not inconsistent with the available data . Ending the chapter suggestions for further research are made.
- Full Text:
- Date Issued: 1963
An x-ray investigation of the thermal decomposition of unirradiated and irradiated silver permanganate.
- Authors: Woods, Geoffrey Steward
- Date: 1963
- Subjects: Decomposition (Chemistry) , Materials -- Thermal properties , Solids -- Thermal properties , Permanganates , Silver compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4511 , http://hdl.handle.net/10962/d1013450
- Description: [From Introduction] The first step in the study of the thermal decompositions of solids is an examination of the kinetics, since this casts much light on the mechanism of the reaction. It must be borne in mind, however, that a theoretical expression, derived on the basis of a particular mechanism, even if it fits the observed experimental results, is not conclusive proof of the validity of the mechanism when applied to the decomposition under examination.
- Full Text:
- Date Issued: 1963
- Authors: Woods, Geoffrey Steward
- Date: 1963
- Subjects: Decomposition (Chemistry) , Materials -- Thermal properties , Solids -- Thermal properties , Permanganates , Silver compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4511 , http://hdl.handle.net/10962/d1013450
- Description: [From Introduction] The first step in the study of the thermal decompositions of solids is an examination of the kinetics, since this casts much light on the mechanism of the reaction. It must be borne in mind, however, that a theoretical expression, derived on the basis of a particular mechanism, even if it fits the observed experimental results, is not conclusive proof of the validity of the mechanism when applied to the decomposition under examination.
- Full Text:
- Date Issued: 1963
Aspects of form and style in Beethoven's string quartets
- Authors: Biesheuvel, Barbara
- Date: 1963
- Subjects: Beethoven, Ludwig van, 1770-1827 -- Quartets -- strings
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2678 , http://hdl.handle.net/10962/d1007645
- Description: Many books have been written which deal with the subject of form and style in Beethoven's works. Most writers, however, seem to be satisfied with superficial descriptions - in some cases merely programatic - which do not explain the underlying problems and treatment of form. Furthermore, no book exists, to my knowledge, which delves so deeply and with such detail as to deduce with almost certain accuracy the inner coherency of the form. It is the aim of this analysis to approach the problem in this way. The edition used for this purpose is that one published by Ernst Eulenberg Ltd. London WI, which was edited from the autograph M.S. by Professor Dr. Wilhelm Altman. No comparisons are made with other editions, and possible printer's and other errors are not considered. I chose the works to be studied here, the three quartets Op. 59, for two reasons: 1) the string quartet medium is one of the most suitable types of instrumental music for the study of form, 2) the Op. 59 quartets belong to a period in Beethoven's life when he was particularly intent upon experimentation in form and development of dimension.
- Full Text:
- Date Issued: 1963
- Authors: Biesheuvel, Barbara
- Date: 1963
- Subjects: Beethoven, Ludwig van, 1770-1827 -- Quartets -- strings
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2678 , http://hdl.handle.net/10962/d1007645
- Description: Many books have been written which deal with the subject of form and style in Beethoven's works. Most writers, however, seem to be satisfied with superficial descriptions - in some cases merely programatic - which do not explain the underlying problems and treatment of form. Furthermore, no book exists, to my knowledge, which delves so deeply and with such detail as to deduce with almost certain accuracy the inner coherency of the form. It is the aim of this analysis to approach the problem in this way. The edition used for this purpose is that one published by Ernst Eulenberg Ltd. London WI, which was edited from the autograph M.S. by Professor Dr. Wilhelm Altman. No comparisons are made with other editions, and possible printer's and other errors are not considered. I chose the works to be studied here, the three quartets Op. 59, for two reasons: 1) the string quartet medium is one of the most suitable types of instrumental music for the study of form, 2) the Op. 59 quartets belong to a period in Beethoven's life when he was particularly intent upon experimentation in form and development of dimension.
- Full Text:
- Date Issued: 1963
Contributions to our knowledge of the biology of Machiloides Delanyi Wygodzinsky and Ctenolepisma Longicaudata Escherich : (Hexapoda Thysanura)
- Authors: Heeg, J. (Jan)
- Date: 1963
- Subjects: Insects -- Adaptation , Insects -- Physiology , Thysanura , Apterygota
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5856 , http://hdl.handle.net/10962/d1012261 , Insects -- Adaptation , Insects -- Physiology , Thysanura , Apterygota
- Description: Among the South African Thysanura, the order Lepismatoidea has spread over the whole sub-continent, while all except one species of the order Machiloidea are confined to the discontinuous forest belt which lies below the escarpment of the inland plateau. The Machiloidea are not , however, strictly confined to the actual forests within their geographical region, some species invading regions of considerable aridity. Investigations on the ecology, water relations and orientation behaviour of a representative species of each order have been carried out. These have revealed that: (i) the physical conditions in the typical niche of the Machiloidea are extremely stable, whereas those in the habitat of the Lepismatoidea are subject to some considerable fluctuation. (ii) the Lepismatoidea are more resistant to desiccation than the Machiloidea; in both cases this resistance is due in part to physical barriers in the cuticle and partly to an active metabolic process. (iii) the Machiloidea rely on their eversible vesicles, situated on the abdominal coxosternites, for the uptake of water which cannot be drunk, such as a thin film of water or soil capillary water. (iv) the Lepismatoidea are able to absorb water from a subsaturated atmosphere. (v) the behavioural responses of both in respect of humidity, temperature, light and gravity, are such as to keep them in conditions within the range of their physiological limitations. From these results it is concluded that the Machiloidea can survive outside the shelter of forests, provided that water is readily available in some form in which it can be absorbed by the animals. The general implications of the results are such as to permit the erection of an hypothesis explaining the distribution of the Thysanura in South Africa in terms of t he availability of wate. The results also lead to speculations on the evolution of the Pterygota.
- Full Text:
- Date Issued: 1963
- Authors: Heeg, J. (Jan)
- Date: 1963
- Subjects: Insects -- Adaptation , Insects -- Physiology , Thysanura , Apterygota
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5856 , http://hdl.handle.net/10962/d1012261 , Insects -- Adaptation , Insects -- Physiology , Thysanura , Apterygota
- Description: Among the South African Thysanura, the order Lepismatoidea has spread over the whole sub-continent, while all except one species of the order Machiloidea are confined to the discontinuous forest belt which lies below the escarpment of the inland plateau. The Machiloidea are not , however, strictly confined to the actual forests within their geographical region, some species invading regions of considerable aridity. Investigations on the ecology, water relations and orientation behaviour of a representative species of each order have been carried out. These have revealed that: (i) the physical conditions in the typical niche of the Machiloidea are extremely stable, whereas those in the habitat of the Lepismatoidea are subject to some considerable fluctuation. (ii) the Lepismatoidea are more resistant to desiccation than the Machiloidea; in both cases this resistance is due in part to physical barriers in the cuticle and partly to an active metabolic process. (iii) the Machiloidea rely on their eversible vesicles, situated on the abdominal coxosternites, for the uptake of water which cannot be drunk, such as a thin film of water or soil capillary water. (iv) the Lepismatoidea are able to absorb water from a subsaturated atmosphere. (v) the behavioural responses of both in respect of humidity, temperature, light and gravity, are such as to keep them in conditions within the range of their physiological limitations. From these results it is concluded that the Machiloidea can survive outside the shelter of forests, provided that water is readily available in some form in which it can be absorbed by the animals. The general implications of the results are such as to permit the erection of an hypothesis explaining the distribution of the Thysanura in South Africa in terms of t he availability of wate. The results also lead to speculations on the evolution of the Pterygota.
- Full Text:
- Date Issued: 1963
On the physiology of the lantern retractor muscle of Parechinus angulosus
- Authors: Boltt, R E
- Date: 1963
- Subjects: Echinodermata -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5900 , http://hdl.handle.net/10962/d1013513
- Description: From Resumé: The lantern retractor muscles of regular echinoids act in almost isometric conditions and a study of their control was considered to be of interest. The retractor muscles cannot be indirectly stimulated from the radial nerves, but proved to be very photosensitive. Their responses to light were therefore studied. The muscles show a complex pattern of contraction in response to illumination, which includes both excitatory and inhibitory components. The possible genesis of these patterns is discussed and examined in the light of the responses of the muscles to direct current stimulation and to drugs. It is concluded that many of the features of the response are undoubtedly neurogenic in origin, but that myogenic activity may possibly also be involved.
- Full Text:
- Date Issued: 1963
- Authors: Boltt, R E
- Date: 1963
- Subjects: Echinodermata -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5900 , http://hdl.handle.net/10962/d1013513
- Description: From Resumé: The lantern retractor muscles of regular echinoids act in almost isometric conditions and a study of their control was considered to be of interest. The retractor muscles cannot be indirectly stimulated from the radial nerves, but proved to be very photosensitive. Their responses to light were therefore studied. The muscles show a complex pattern of contraction in response to illumination, which includes both excitatory and inhibitory components. The possible genesis of these patterns is discussed and examined in the light of the responses of the muscles to direct current stimulation and to drugs. It is concluded that many of the features of the response are undoubtedly neurogenic in origin, but that myogenic activity may possibly also be involved.
- Full Text:
- Date Issued: 1963
Some properties of a model F1 layer of the ionosphere
- Authors: De Jager, Gerhard
- Date: 1963
- Subjects: Ionosphere , Ionospheric electron density
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5515 , http://hdl.handle.net/10962/d1011046 , Ionosphere , Ionospheric electron density
- Description: The present work was initially aimed at providing an explanation for some of the phenomena that occur in the ionosphere at sunrise. The approach that was taken was to determine the changes that take place on a theoretical model of the ionosphere and then to compare these with observations. A prerequisite for this approach was a theoretical model that would show, among other things, a bifurcation of the F layer during daytime without making unjustified arbitrary assumptions. The absence of such a model, particularly as far as non-equilibrium conditions are concerned, resulted in the present attempt to provide such a model for the F1 region.
- Full Text:
- Date Issued: 1963
- Authors: De Jager, Gerhard
- Date: 1963
- Subjects: Ionosphere , Ionospheric electron density
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5515 , http://hdl.handle.net/10962/d1011046 , Ionosphere , Ionospheric electron density
- Description: The present work was initially aimed at providing an explanation for some of the phenomena that occur in the ionosphere at sunrise. The approach that was taken was to determine the changes that take place on a theoretical model of the ionosphere and then to compare these with observations. A prerequisite for this approach was a theoretical model that would show, among other things, a bifurcation of the F layer during daytime without making unjustified arbitrary assumptions. The absence of such a model, particularly as far as non-equilibrium conditions are concerned, resulted in the present attempt to provide such a model for the F1 region.
- Full Text:
- Date Issued: 1963
Studies on certain aspects of the neuromuscular physiology of insects
- Authors: Moran, V C (V. Cliff)
- Date: 1963
- Subjects: Insects -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5866 , http://hdl.handle.net/10962/d1012879
- Description: It is well known that high potassium ion concentrations depolarize nervous tissue and it has been suggested that the nerve sheath surrounding the peripheral nerves of insects serves as a protective barrier for the exclusion of potassium ions, in the haemolymph, from the immediate environment of axons. Further it is known that the concentration of potassium ions in the haemolymph of phytophagous insects is far higher than that in predatory forms; this has led to the suggestion that the nerve sheath in plant feeding insects should be more highly developed than that of entomophagous insects. In this work the structure of the nerve sheath in phytophagous and predatory insects has been studied and this assumption has been shown to be groundles. However, preliminary experiments on the effects of ions and drugs on the peripheral nerves of phytophagous and predatory insects have shown that there is a definite difference in susceptibility between the nerves of these two forms and this has led to the postulate of a diffusion barrier beneath the level of the nerve sheath, which is more highly developed in phytophagous than in predatory forms. The properties of this second barrier are discussed. Part 1. , During the course of the work which has been described in Part 1- an outbreak of large saturniid moths Nudaurelia cytherea capensis Stoll.) occurred in the Grahamstown area. It was felt that an investigation into the properties of the flight motor of this moth, which has an extremely low wing beat frquency, might be rewarding as our knowledge of the flight motor in insects is limited to those with very much higher wing beat frequencies than that of this moth. The anatomy, innervation and histology of the flight muscles of Nudaurelia are described and it is shown that the flight motor of this moth is functionally different to that of other insects which have been investigated. Further, Nudaurelia shows a characteristic warm-up fluttering of the wings prior to flight - this phenomenon has also been examined in the following investigation. This study has yielded information about the location of a warm-up centre in the central nervous system of this moth. Part 2.
- Full Text:
- Date Issued: 1963
- Authors: Moran, V C (V. Cliff)
- Date: 1963
- Subjects: Insects -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5866 , http://hdl.handle.net/10962/d1012879
- Description: It is well known that high potassium ion concentrations depolarize nervous tissue and it has been suggested that the nerve sheath surrounding the peripheral nerves of insects serves as a protective barrier for the exclusion of potassium ions, in the haemolymph, from the immediate environment of axons. Further it is known that the concentration of potassium ions in the haemolymph of phytophagous insects is far higher than that in predatory forms; this has led to the suggestion that the nerve sheath in plant feeding insects should be more highly developed than that of entomophagous insects. In this work the structure of the nerve sheath in phytophagous and predatory insects has been studied and this assumption has been shown to be groundles. However, preliminary experiments on the effects of ions and drugs on the peripheral nerves of phytophagous and predatory insects have shown that there is a definite difference in susceptibility between the nerves of these two forms and this has led to the postulate of a diffusion barrier beneath the level of the nerve sheath, which is more highly developed in phytophagous than in predatory forms. The properties of this second barrier are discussed. Part 1. , During the course of the work which has been described in Part 1- an outbreak of large saturniid moths Nudaurelia cytherea capensis Stoll.) occurred in the Grahamstown area. It was felt that an investigation into the properties of the flight motor of this moth, which has an extremely low wing beat frquency, might be rewarding as our knowledge of the flight motor in insects is limited to those with very much higher wing beat frequencies than that of this moth. The anatomy, innervation and histology of the flight muscles of Nudaurelia are described and it is shown that the flight motor of this moth is functionally different to that of other insects which have been investigated. Further, Nudaurelia shows a characteristic warm-up fluttering of the wings prior to flight - this phenomenon has also been examined in the following investigation. This study has yielded information about the location of a warm-up centre in the central nervous system of this moth. Part 2.
- Full Text:
- Date Issued: 1963
Studies on the behaviour of unfed blue tick larvae (Boophilus decoloratus)
- Authors: Goldsmid, John Marsden
- Date: 1963
- Subjects: Boophilus -- South Africa , Ticks -- Behavior -- South Africa , Ticks -- Physiology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5852 , http://hdl.handle.net/10962/d1012044 , Boophilus -- South Africa , Ticks -- Behavior -- South Africa , Ticks -- Physiology -- South Africa
- Description: Ticks "are not merely annoying pests but surpass all other anthropods in the number and variety of disease agents for which they are carriers (Chandler 1955). This statement is certainly true of Boophilus decoloratus (Koch), the blue tick, which is probably one of the most important ticks in South Africa. Various studies have been made on the blue tick in Africa, among which are investigations on taxonomy (Hoogstraal 1956); distribution (Theiler 1949 and 1962); ecology (Kraft 1961); disease transmission (Neitz and du Toit 1938; du Toit 1947; Neitz 1956 a and b); control and resistance to insecticides (du Toit, Graf and Bekker 1941; Whitnall and Bradford 1947; Whitehead 1958 and 1959) To date, the behaviour of Boophilus decoloratus has not been studied to any extent. The aim of the present work is to analyse the behaviour of the unfed larvae into its constituent patterns in order to determine what are the significant environmental factors which affect this behaviour. It is also hoped that the present laboratory studies might help in understanding their behaviour in the field. Intro., p. 1.
- Full Text:
- Date Issued: 1963
- Authors: Goldsmid, John Marsden
- Date: 1963
- Subjects: Boophilus -- South Africa , Ticks -- Behavior -- South Africa , Ticks -- Physiology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5852 , http://hdl.handle.net/10962/d1012044 , Boophilus -- South Africa , Ticks -- Behavior -- South Africa , Ticks -- Physiology -- South Africa
- Description: Ticks "are not merely annoying pests but surpass all other anthropods in the number and variety of disease agents for which they are carriers (Chandler 1955). This statement is certainly true of Boophilus decoloratus (Koch), the blue tick, which is probably one of the most important ticks in South Africa. Various studies have been made on the blue tick in Africa, among which are investigations on taxonomy (Hoogstraal 1956); distribution (Theiler 1949 and 1962); ecology (Kraft 1961); disease transmission (Neitz and du Toit 1938; du Toit 1947; Neitz 1956 a and b); control and resistance to insecticides (du Toit, Graf and Bekker 1941; Whitnall and Bradford 1947; Whitehead 1958 and 1959) To date, the behaviour of Boophilus decoloratus has not been studied to any extent. The aim of the present work is to analyse the behaviour of the unfed larvae into its constituent patterns in order to determine what are the significant environmental factors which affect this behaviour. It is also hoped that the present laboratory studies might help in understanding their behaviour in the field. Intro., p. 1.
- Full Text:
- Date Issued: 1963