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A structural investigation of the sulphated polysaccharide from Aeodes ulvoidea Schmitz

  • Authors: Allsobrook, Anthony John Robert
  • Date: 1973
  • Subjects: Red algae -- Composition Polysaccharides
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4437 , http://hdl.handle.net/10962/d1007482
  • Description: Aeodes ulvoidea, a red seaweed of the Grateloupiaceae, yielded a highly sulphated polysaccharide which was shown to contain D- and L-galactose, 4-0-methy-L-galactose, 2-0-methyl - D- and L-galactose and 6-0-methyl-D-galactose, together with chromatographic traces of xylose and mannose. The sulphate was not labile to alkali, but it was largely removed with methanolic hydrogen chloride. Periodate oxidation of the polysaccharide, methylation of the de sulphated polysaccharide, and investigation of fifteen oligosaccharides from partial hydrolysis and acetolysis studies of the polysaccharide, indicate that (a) the polysaccharide is composed of a backbone of D-galactose residues which are 1,3- and 1,4-linked (b) at least some regions of alternating structure do occur (c) the 2-0-methylgalactose is linked through the 4-position (d) the 4-0-methyl-L-galactose is present as single unit side chains glycosidically linked to the galactose backbone at position 6, and (e) most of the 6-0-methyl-D-galactose is linked to the 4-position of 2-0-methyl-D-galactose.
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  • Date Issued: 1973

A contribution to the biology of Tilapia mossambica Peters in Lake Sibaya, South Africa

  • Authors: Bruton, Michael N
  • Date: 1973
  • Subjects: Cichlids , Tilapia , Mozambique tilapia
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5839 , http://hdl.handle.net/10962/d1009950 , Cichlids , Tilapia , Mozambique tilapia
  • Description: An account is given of some aspects of the biology of Tilapia mossambica Peters in Lake Sibaya, South Africa. Previous work on Tilapia in Lake Sibaya is reviewed. Apart from brief gillnet surveys, which recorded the species' presence, no research on T. mossambica had been performed at Lake Sibaya before the two-year study of Minshull who collected data on food preferences, depth distribution of juveniles and breeding biology of adults. The main physiographical features of the lake are outlined. Lake Sibaya is a warm shallow coastal lake with extensive shallow terraces in the littoral which shelve abruptly into underwater valleys. The substrate is predominantly sandy. Aquatic macrophytes are generally restricted to water 1-7 m deep. Adult fishes (over 8 cm SL) are usually absent from water deeper than 12 m and shallower than 0.5 m, whereas juveniles may occur at all depths, and fry only in very shallow water. T. mossambica inhabits the littoral in the warm and transition periods (August to April) but moves into deep water in the cool season (May to July). Exposed and sheltered shallow areas are utilised for different purposes by adult fishes, the former for nesting, and the latter for feeding and mouth-brooding. Habitat selection by males was governed by nest site selection. Habitat Nests were most common in sheltered, sparsely vegetated littoral and sublittoral areas, but also present in well-vegetated sheltered areas. Breeding females preferred sheltered littoral areas but ventured onto the terrace to release the young. Juvenile and fry T. mossambica inhabited shallow exposed shores with a temperature gradient which reversed diurnally. The breeding, shoaling and feeding behaviour of T. mossambica is described, and integrated with data on T. mossambica from other systems. The breeding season spans seven months. Shoaling takes place in shallow water probably as a means of protection. T. mossambica is an omnivorous feeder relying largely on diatoms. The main predator is probably the barbel Clarias gariepinus, but avian predators may be more important. A method whereby the time of formation of rings on the scales of T. mossambica is described. The fishes were found to reach maturity after one year at a length of about 8 cm in females, and after two years at 10 cm in males. The breeding population had a standard length mode of 14 cm (females) and 17 cm (males). The maximum final size was about 24 cm SL. An estimate of the standing crop for fishes in the littoral and subiittoral areas of the eastern and southern shores of the south basin is given. The data were derived from a mark and recapture The biology of T. mossambica in Lake Sibaya as revealed by the present study is discussed with reference to data on the same and similar species in other systems. The utilis ation of the available resources in the lake by T. mossambica is commented upon, and reference is made to the significance of stunting, and the import ance of the retention of generalised characters for the successful habitation of the cyclically-renewed habitat of the littoral. Precocious breeding in T. mossambica is regarded as a functional adaptation which increases the proportion of fishes small enough to utilise the rich food resources in shallow water.
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  • Date Issued: 1973

The ability of four species of Southern African cichlid fishes to enter deep water

  • Authors: Caulton, Mark S
  • Date: 1973
  • Subjects: Cichlids -- Africa, Southern , Tilapia
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5840 , http://hdl.handle.net/10962/d1010429 , Cichlids -- Africa, Southern , Tilapia
  • Description: Using an experimental pressure chamber the rates of descent and the maximum depths of buoyancy equilibrium of some cichlid fishes were tested. Tilapia mossambica juveniles could descend to depths greater than 30 metres very rapidly. At 22°C small sub adult male fish (length ± 160 mm) could descend to a maximum buoyancy depth of 20 metres, small sub adult females to 13 metres while large adults (length ± 200 mm) of both sexes could descend to 11 metres. The fish generally take 4 to 5 days to reach their maximum equilibration depth. At 30°C mature adult male and female T.mossambica increased their maximum equilibration depth to 20 metres and at 15°C showed a decrease to a maximum depth of 6.7 metres. Temperature affects the rates of descent in a similar manner. T.rendalli can descend to 7.5 metres at 22°C. T.sparmanii can descend to 15 metres at 22°C. Hemihaplochromis philander fry and young juveniles are not affected by pressure. Adult males can descend to 16 metres at 22°C and 20 metres at 30°C. Adult females can descend to 26 metres at 22°C and 27 metres at 30°C. In T.mossambica oxygen appears to be the only gas secreted into the swimbladder to compensate for buoyancy loss. The haemoglobin of T.mossambica showed a marked Bohr and Root effect. Increased rates of descent with increased temperature are believed to be due to increased O₂ uptake, heart output etc. rather than as a direct effect of blood chemistry. The swimbladder wall of T.mossambica is extremely thin (2.8 ∕∪ m) and consequently a large amount of gas is lost through passive diffusion. Diffusion is not affected by temperature, consequently the increased secretory rates at higher temperatures are not balanced by a proportionately higher diffusion loss, thus enabling the fish to maintain a deeper buoyancy equilibrium at higher temperatures. Summary, p. 62-63.
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  • Date Issued: 1973

'n Evaluering van onderwysvoorsienings en onderwysfasiliteite in die Karoo-distrikte Aberdeen, Graaff-Reinet, Jansenville-Klipplaat en Murraysburg vir die hoofbevolkingsgroepe Blank, Kleurling en Bantoe

"The isolation and estimation of low molecular weight N-nitrosamines in biological materials"

  • Authors: Du Plessis, Leo Stephen
  • Date: 1973
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:21176 , http://hdl.handle.net/10962/6750
  • Description: Summary: Low molecular weight N-nitrosamines were detected by ultraviolet, infrared, nuclear magnetic resonance, mass spectral, thin-layer chromatographic and gas liquid chromatographic means. A method for the estimation of dimethylnitrosamine, diethylnitrosamine, ethal-n-propylnitrosamine and di-n-propylnitrosamine has been developed. The method involves the isolation of the nitrosamines in an aqueous distillate by freeze-drying. After extraction of the nitrosamines from the aqueous distillate by means of dichloromethane, their separation and quantitative estimation are achieved by gas liquid chromatography of the extract. The procedure can be extended down to the ppb range. Dimethylnitrosamine was isolated from an extract of Solanum incanum and identified by gas liquid chromatography on four different columns, infrared and nuclear magnetic resonance spectroscopy.
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  • Date Issued: 1973

A study of Jewish identification and commitment in Johannesburg

  • Authors: Dubb, Allie A
  • Date: 1973
  • Subjects: Jews -- South Africa -- Johannesburg Johannesburg (South Africa) -- Social conditions
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3362 , http://hdl.handle.net/10962/d1011564
  • Description: The present study is an investigation of the nature and extent of Jewish identification and commitment in the Johannesburg Jewish Community. Jewish identification is defined as the attitudes and behaviour through which Jews express their identity with each other and with the Jewish group. It is conceived as comprising several dimensions - structural, cultural, religious, etc . - each of which may be assessed in terms of attitudes and/or behaviour. The aim of the study is, in the first place to describe the various dimensions of Jewish identification and to discover relations between them, and between them and other variables. Fieldwork consisted in the administration of a schedule, lasting about an hour, by trained interviewers to a quota sample of Johannesburg Jews. The schedule comprised questions relating to behaviour, attitudes and personal particulars. These data were augmented by several intensive interviews and by interviewers' observations. The final sample consisted of 286 men and women, in almost equal proportions, who had answered affirmatively the initial question, "Are you Jewish?" Five hypotheses were postulated, mainly on the basis of the findings of several previous studies in the United States. Briefly, it was postulated: firstly, that Jews would tend to identify through their attitudes to a greater extent than through actual behaviour; secondly that the area in which identification on the behavioural level was most likely to be manifested, was in patterns of social relations; thirdly, that observance of religious rituals was primarily a manifestation of identification rather than religious commitment ; fourthly; that there was some conflict between the desire to maintain the group and the feeling that barriers between ethnic groups should be minimal; and, finally , that the boundaries of the .Jewish community could be defined most adequately in terms of the relevance to community membership to the allocation of roles rather than in cultural terms. The first hypothesis had to be partially rejected; the remaining four were confirmed by the data. The study comprises eleven Chapters: in the first four, the problem is defined, hypotheses stated and research and sampling methods discussed; in Chapter Five, the demographic background is described, and in Chapters Six to Ten the findings relating to the various dimensions are presented and the hypotheses tested. In the final Chapter, the hypotheses and various specific findings are discussed in relation to their wider theoretical implications, as well as to their possibilities for further research and practical applications.
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  • Date Issued: 1973

An investigation of the determinants of the spatial characteristics of figure placements

  • Authors: Edwards, David J A
  • Date: 1973
  • Subjects: Characters and characteristics , Psychology, Applied , Cross-cultural studies
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3205 , http://hdl.handle.net/10962/d1011739 , Characters and characteristics , Psychology, Applied , Cross-cultural studies
  • Description: The doll placement technique is a projective instrument which yields objective measures from which inferences may be drawn. Subjects place pairs of dolls to represent social encounters described to them by the experimenter. When the dolls have been placed, the distance between them and the angles at which they stand can serve as a source of information either about the personality of the placer or about the way in which he perceives the relationship between the interactors represented. Most experimental work employing figure placements has used flat felt figures which subjects have mounted on a flannel graph. This method limits an investigator to one dependent variable, the inter-figure distance. However if three dimensional dolls are placed three dependent measures can be derived from a placement, one of distance and two of orientation. It has been demonstrated that a reliable correlation exists between the spatial relations between figures placed by a person and the spatial relationships between real interactors. The theoretical analysis of the determinants of interpersonal distance and orientation in social encounters which has been worked out by students of non-verbal behaviour is therefore able to serve as a basis for the interpretation of the spatial characteristics of doll placements. Previous work with the doll placement technique has concentrated on the distance between dolls. The present study explored the determinants of figure orientations. Firstly an analysis was made of the types of orientation pattern that can occur when two persons are involved in a social encounter. Secondly, an experiment was performed which was designed to explore whether asymmetry in an orientation pattern might act as a cue to determine how individual figures in a pair were perceived. Thirdly, two doll placement studies were performed which were designed to investigate the conditions giving rise to asymmetrical orientation patterns and the determinants of direct and indirect orientations. The confidence or anxiety attributed to an interactor represented by a figure proved to be a major determinant of its spatial position. The results of the study indicate that the use of the angle measures in the analysis of doll placements considerably enhances the value of the technique. It is argued that the doll placement method could be profitably employed both as a clinical instrument and as a research tool for cross-cultural psychology.
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  • Date Issued: 1973

Aloe distans, Saldanha Bay

Aloe alooides, Eastern Transvaal

Aloe lutescens, Northern Transvaal

Sport und Soziologie : Die Dimensionen der Sozialen Elemente der Sport-Soziologie in Vergangenheit und Gegenwart, mit besonderem Blick auf Südafrika

  • Authors: Gilbert, Christa Luise
  • Date: 1973
  • Subjects: Sports -- Sociological aspects Sports -- South Africa Sports -- Social aspects -- South Africa
  • Language: German
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5149 , http://hdl.handle.net/10962/d1012094
  • Description: Kein anderer als Schiller bringt mit seinen Worten das tiefe Empfinden fur das Spiel so vernehmlich zum Ausdruck und die unternommene Studie der Sport- Soziologie so greifbar nahe. Den der Mensch im Spiel und in seinem menschlichen Verhalten durch das Spiel fugt die beabsichtigte Studie zum neuen Konzept des modernen Sportes zussammen und begründet das fundamentale Suchen menschlicher Bedürfnisse des Erlebens durch den Sport - manifestiert weiterhin durch die Worte von Caillois: "Sage mir, was Du spielst - und ich will Dir sagen, wer Du bist" Intro., p. 1.
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  • Date Issued: 1973

Dr Johnson's critical assumptions in the preface to Shakespeare: an essay in descriptive method

  • Authors: Gouws, John Stephen
  • Date: 1973
  • Subjects: Johnson, Samuel, 1709-1784 -- Criticism and interpretation , Shakespeare, William, 1564-1616 -- Criticism and interpretation
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2298 , http://hdl.handle.net/10962/d1012073 , Johnson, Samuel, 1709-1784 -- Criticism and interpretation , Shakespeare, William, 1564-1616 -- Criticism and interpretation
  • Description: "His criticism may be considered as general or occasional. In his general precepts, which depend upon the nature of things and the structure of the human mind, he may doubtlessly be safely recommended to the confidence of the reader: but his occasional and particular positions were sometimes interested, sometimes negligent, and sometimes capricious." With certain qualifications, it would be the opinion of those critics who share a great admiration of the man that this statement might well have been made of Johnson himself. There are those, however, whose esteem of Johnson is perhaps not so great. One thus finds Alan Tate writing: "One is constantly impressed by Johnson's consistency of point of view, over the long pull of his self-dedication to letters. There is seldom either consistency or precision in his particular judgements and definitions -- a defect that perhaps accounts negatively for his greatness as a critic: the perpetual reformulation of his standards, with his eye on the poetry, has done much to keep eighteenth century verse alive in our day. His theories (if his ideas ever reach that level of logical abstraction) are perhaps too simple for our taste and too improvised; but his reading is disciplined and acute." Tate is eager to perpetuate the notion of Johnson as a critic with a massive common sense and little more, an imputation which Johnson would not only resent, but dismiss as short-sighted. Intro., p. 1.
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  • Date Issued: 1973

Some properties of magnetospheric electrons observed west of Sanae

  • Authors: Greener, James G
  • Date: 1973
  • Subjects: Magnetosphere
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5523 , http://hdl.handle.net/10962/d1012091 , Magnetosphere
  • Description: The southern hemisphere has always been the neglected twin in the field ot geophysical research. The reasons for this are certainly not in the realm of science but in the history of man and his development in the northern half of the globe. Geophysically, however, our southern half provides a wealth of interesting problems and anomalies. Roederer (1966) explains the use of this word 'anomaly' by showing what some of the oddities of the southern hemisphere are, and by contrasting them with the corresponding regions of the earth across the equator. The principal feature is of course the geomagnetic surface field strength minimum at a point in the South Atlantic ocean very near the coast of Brazil. Intro., p. 1.
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  • Date Issued: 1973

Aspects of the biology of aestivation in Bulinus (Physopsis) africanus (Krauss) (Gastropoda, Pulmonata)

  • Authors: Heeg, J. (Jan)
  • Date: 1973
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:21054 , http://hdl.handle.net/10962/6178
  • Description: Aestivation, a period of dormancy during hot, dry conditions, is known to occur in both the Prosobranchia and the Pulmonata among freshwater Gastropoda. While there have been numerous accounts, mainly by field ecologists concerned with bilharziasis control, of the survival value of aestivation in the Gastropoda, little is known of its underlying physiological mechanisms. Results of investigations into the physiological basis of aestivation in the freshwater Prosobranchia, confined to the family Ampulariidae, have been conflicting, fundamental differences having been shown to exist between different species of the genus Pila . Only a single comprehensive study, that by von Brand and his coworkers on the planorbid snail Australorbis glabratus*, forms the basis of our knowledge of the aestivation process in the aquatic Pulmonata. In view of the conflicting results obtained in investigations on freshwater Prosobranchia, the general applicability of the findings for Australorbis glabratus to other freshwater Pulmonata was open to question. The present investigation on the planorbid snail Bulinus (Physopsis) afriaanus, a species known to be a successful aestivator, was prompted by the obvious need for a further comprehensive study on an aquatic pulmonate species . The results presented here show that aestivation in this species is a definite physiological state, characterised by a depression of the metabolic rate, which not only aids in husbanding the snails I metabolic resources. during the enforced starvation which must necessarily accompany aestivation, but also constitutes a form of resistance adaptation to the transient high temperatures which aestivating snails are bound to encounter. Loss of body water is shown to be important in initiating aestivation, but it is also the factor most likely to prove lethal during the course of aestivation. The results confirm and extend the earlier findings for Australorbis glabratus. The results are discussed in the context of our present knowledge of aestivation in other Gastropoda, both aquatic and terrestrial, and also in relation to other forms of resistance adaptation. As expected, the investigation raises more questions than it answers, thus directions for further research, arising out of the present findings, are suggested.
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  • Date Issued: 1973

The history, organization and training of wind bands

  • Authors: Honey, Albert Edward
  • Date: 1973
  • Subjects: Band music -- Instruction and study , Band music -- Analysis, appreciation , Bands (Music) -- Instruction and study , Bands (Music)
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:2692 , http://hdl.handle.net/10962/d1013343
  • Description: From introduction: The decision to use the term "Wind Band" in connection with this work was made after much careful deliberation. The English word "Band" is derived from the French "bande" meaning a group of players. It was first applied in this context in England when the Twenty-four Violins at the Court of Charles II (in emulation of "Le Vingt-quatre Violons du Roi at the Court of Louis XIV of France) were known in England as "The King's Band "Band" is a title generally given at the present time to any of instrumentalists, and indeed, many of the World's most famous conductors have been known to refer to any large symphony orchestra as "The Band" and the dressing-room of every Symphony or Concert orchestra in the British Isles is invariably called "The Band-Room"
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  • Date Issued: 1973

Zulu dancing troupe performing at All Saints: All Saints, 1973

Cattle against the Drakensberg foothills, 1973

Christo-centric reconciliation : being a dissertation considering reconciliation with particular reference to; the baptism of Jesus, the temptations of Jesus, the title of Son of Man as used by Jesus, and the Pauline texts which refer to reconciliation

  • Authors: Jeannot, Hugues Donald
  • Date: 1973
  • Subjects: Reconciliation -- Biblical teaching , Jesus Christ -- Temptation , Baptism -- Biblical teaching , Son of Man -- Biblical teaching
  • Language: English
  • Type: Thesis , Bachelor , BDiv
  • Identifier: vital:1278 , http://hdl.handle.net/10962/d1013397
  • Description: [From Introduction]. "God, ... through Christ reconciled us to himself and gave us the ministry of reconciliation." "Among all churches throughout the world there is a growing conviction that God's great reconciliation in Jesus Christ is still the answer desperately needed by modern man." The United Presbyterian Church U.S.A.'s Confession of 1967 made "reconciliation the all-embracing category for describing God's work and man's response, including especially his response in social and political action".
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  • Date Issued: 1973

Studies in the South African Bulbous liliaceae

  • Authors: Jessop, John Peter
  • Date: 1973
  • Subjects: Bulbs (Plants) -- South Africa Liliaceae -- South Africa Lilies -- South Africa Liliaceae -- Classification -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4261 , http://hdl.handle.net/10962/d1012563
  • Description: The work comprises two principal sections; an attempt at ellucidating generic relationships in the South African bulbous Liliaceae, and a revision of the species of selected genera. In the first section the approaches investigated were: 1) A re-evaluation of the nature of the bulb apex, showing a likelihood that certain groups possess axillary and other groups terminal inflorescences. 2) An investigation of leaf anatomy, showing that most genera have very similar leaf structure, but that a few genera do differ from this norm. Scilla (Euscilla) generally possesses a distinctly lignified bundle sheath and the Urginea-Drimia group show a great range in structures - including a palisade. 3) An impression technique to determine patterns in the surface of the leaf cuticle. A close correlation appears to exist between these patterns and leaf shape. 4) Scanning Electron Microscope pictures of pollen revealed a considerable uniformity within the group and between this group and most other members of the Liliaceae. 5) Scanning Electron Microscope pictures of seeds revealed two main groups in the bulbous Liliaceae determined on the appearance of the cell walls of the testa. 6) A simple chromatographic technique was not found to be useful. 7) An investigation of chromosome numbers of. 44 samples of 15 species supplemented published data in allowing an analysis to be made of the application of chromosome numbers to generic concepts. Many genera of the Liliaceae - especially in the bulbous group - have extremely variable chromosome numbers. It is considered that numbers are more applicable to tribal than to generic concepts. Few indications of meiotic abnormalities were detected. Phylogenetic and taxonomic aspects of the genera of the bulbous Liliaceae are discussed and a key to the South African bulbous Liliaceae genera constructed. The following generic alterations are proposed: Ledebouria to be split off Scilla. Schizocarphus to be placed in Scilla. Resnova to be placed in Drimiopsis. The Astemme section (= Neobakeria) to be removed from Polyxena and placed in Massonia. The Cape species of Hyacinthus to be placed in Polyxena. Thuranthos, Urgineopsis and Urginea to be placed in Drimia. It is suggested that Schizobasis and Bowiea are of great importance in explaining the origin of Asparagus - possibly even directly from this group. In the generic revisions, thirteen genera are dealt with including typification, synonymy, distribution, field notes, species descriptions and keys. 67 species are dealt with, of which three are new (all in Ledebouria), and 31 new combinations are proposed.
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  • Date Issued: 1973

Nyamaropa

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