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A comparative study of the vocational interests of black and white school-leaving boys in South Africa

  • Authors: Breger, Richard Allen
  • Date: 1976
  • Subjects: Vocational interests -- South Africa , Vocational interests -- Cross-cultural studies
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3200 , http://hdl.handle.net/10962/d1009692 , Vocational interests -- South Africa , Vocational interests -- Cross-cultural studies
  • Description: This is an exploratory study to compare the vocational interests of Black and White school-leaving boys in South Africa. The aim of the study is, first, to test the hypothesis that the samples hold similar stereotypes of vocations and that they structure interest fields in a similar way; and, second. to test the hypothesis that the vocational interests of the samples are different. The samples comprise four hundred and ten matriculants from schools in Johannesburg and Soweto. The methodological requirements for conducting cross-cultural research are adhered to as far is practically possible. The main findings provide general support for the hypotheses. It is found that the Black and White samples have similar vocational stereotypes and that they structure interest fields similarly, and in a way which closely approximates the reported structures characteristically found in Western culture. The Black and White samples differ in their vocational interests, although there are also similarities.
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  • Date Issued: 1976

A critical investigation of the role of the textbook in the teaching of English grammar (first language, higher grade) in the contemporary Cape senior school

A study of factors affecting precision in atomic absorption spectrometry

  • Authors: Roos, Johannes Tielman Hofmeyr
  • Date: 1976
  • Subjects: Atomic absorption spectroscopy
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4490 , http://hdl.handle.net/10962/d1013080
  • Description: 1. The effect of deviations from Beer's law on the precision of atomic absorption analysis has been examined from a theoretical point of view, and a function has been derived which makes it possible to evaluate quantitatively the effect of calibration curvature on the precision of analysis. The influence of incomplete sample volatilization on calibration curvature has been briefly investigated. 2. Possible error sources in atomic absorption spectrometry have been classified according to the "error function" (i.e., the dependence, upon transmittance T, of the uncertainty dT in a given transmittance measurement) with which they are associated. The magnitude of the contribution from each component function to the overall error function has been evaluated quantitatively, and it has been shown that the major component in nearly every case examined is that associated with the dynamic nature of the flame. Concentration ranges for optimum precision are suggested. 3. The effect of varying instrumental parameters on precision has been investigated, and generalized conditions for best precision have been ascertained. 4. The effect of an initial solvent extraction step on the precision of atomic absorption has been investigated for the elements copper and lead. It is shown that solvent extraction may be used to improve both the analytical sensitivity and the precision of analysis when very low concentrations of metal are determined. 5. The precision of analytical methods involving atomic absorption spectrometry has been studied, and the standard deviations compared with those obtained for the analysis of similar samples by means of a variety of other methods of analysis, both instrumental and classical.
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  • Date Issued: 1976

Agnation, alternative structures, and the individual in Chopi society

An account and explanation of the increased role played by women in the modern Olympic games 1896-1972

  • Authors: Handley, Bridget Mary
  • Date: 1976
  • Subjects: Olympics -- History , Sports for women -- History , Women Olympic athletes
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:5150 , http://hdl.handle.net/10962/d1012149 , Olympics -- History , Sports for women -- History , Women Olympic athletes
  • Description: This thesis is concerned with the participation of women and girls in the Olympic Games. In these days of women's liberation it seemed appropriate to try to put together the knowledge available about women competitors and their participation in the Olympics. I have tried to set out an overall view with some historical background and then an account leading up to the initial and continuing participation of women in the Games and showing the reasons for the slow beginning and the gradual increase in numbers of competitors and sports. I have also tried to evaluate some well known myths and misconceptions concerning participation and made an attempt with the use of research data to disprove many of these.
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  • Date Issued: 1976

Art and the Odyssey : the exploration into the Homeric poems, in particular the Odyssey, as symbolic of artistic experience

Aspects of the feeding ecology of three common Sparid fish in the littoral zone at Clayton's Rocks in the Eastern Cape, with notes on their biology

  • Authors: Christensen, Mikkel S
  • Date: 1976
  • Subjects: Sparidae -- Physiology , Sparidae -- Ecology
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5356 , http://hdl.handle.net/10962/d1010476 , Sparidae -- Physiology , Sparidae -- Ecology
  • Description: The feeding interrelationships of three sparid fish was studied in the littoral zone during low tide at Clayton's Rocks in the Eastern Cape. The three species appeared in the study area only when between 9 and 10 mm long (SL), and remained resident until a length of approximately 120 fmm was reached. No sexually mature specimens occurred in the study area as large adults only use the intertidal zone for feeding purposes at high tide. From first recruitment into the littoral zone at 9 mm SL until some 35 mm long, the diet of Diplodus sargus consists of harpacticoid copepods and amphipods. Ingestion of amphipods and green algae increases with increased size of fish. Chironomid larvae, cirripede nauplii and an unidentifiable planktonic larva are important food items of small juveniles ( 50 mm), while diatoms are significant in larger juveniles (25 to 80 mm) in the spring/early summer season. The gut is short and the teeth are incisiform, backed by several rows of molars which increase in size and number with age. D.cervinus was almost completely carnivorous in the size range studied. The juveniles found on harpacticoid copepods and chironomid larvae while between 10 and 20 mm long. The diet then consists mainly of the shrimp Palaemon pacificus until the fish are 50 mm long and then amphipods until 100 mm long. All fish larger than this feed prodominantly on polychaetes. The gut is short and the teeth are similar to those of Q. sargus although there are fewer molars. From its first appearance at 10 mm, Sarpa salpa feeds mainly on harpacticoid copepods until 25 mm long. Diatoms then predominate in the diet, red algae also being taken until 75 mm long. Larger size classes are herbivores, feeding almost equally on red and green algae. Corresponding changes in gut length and dentition are reported, juveniles having a short gut and conical teeth and adults a long intestine and cuspidate, incisiform teeth. Marked ecological separation was observed between the three species. Spatial, temporal , behavioural and dietary differences were found . Q. sargus has continuous recruitment of juveniles into the littoral zone, S..salpa appears between July and early September and Q.cervinus is recruited from late September to November. Competition between small juveniles is reduced by cyclic abundances of food items important to each species and the sub-adults feed on different foods. Some competition exists between large juveniles of Q. sargus and Q.cervinus, but separation is maintained as individuals of the two species feed at different levels of the water column and in different parts of the littoral zone.
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  • Date Issued: 1976

Aspects of the geochemistry of the Karroo dolerites and basalts of the north-eastern Cape

  • Authors: Robey, Julian van Aardt
  • Date: 1976
  • Subjects: Diabase -- South Africa -- Cape of Good Hope , Basalt -- South Africa -- Cape of Good Hope , Geochemistry -- South Africa -- Cape of Good Hope
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5060 , http://hdl.handle.net/10962/d1013070
  • Description: The Birds River Gabbro Complex is intruded into sediments of the Karroo Stormberg Group in the area SW of Dordrecht in the northeastern Cape. A geochemical investigation, restricted to the igneous rock suite, gabbro-ferrogabbro-ferrotholeiite, presents new major-element data as well as data for twelve trace elements - Ba, Sr, Rb, Zr, Y, Nb , Zn, Cu, Ni, Co, V and Cr. The strong degree of differentiation of Kokstad-type tholeiitic magma in the Birds River intrusion, as noted by previous investigators, is revealed in variation diagrams in which data are plotted against a simple index of fractionation. Later differentiates are strongly enriched in Si, Ti, Fe, Na, K, P, Ba, Rb, Zr, Y, Nb, Zn and Cu but depleted in Mg, Ca, AI, Ni, Co and Cr. Extreme differentiation resulted in a strong depletion of Ti, Fe, P, Cu and V in the most highly evolved ferrotholeiites. Field evidence suggests the initial emplacement of strongly fractionated magmatic residua derived from fractional crystallization processes in a magma chamber at depth during cauldron subsidence of a mass of sediments within an annular fracture. These porphyritic, in part glassy, ferrotholeiites are enriched in Si, Na, K, Ba, Zr, Rb, Y, Nb and Zn and were engulfed by a later episode of renewed hypabyssal intrusive activity from the original source area. The younger gabbro was emplaced in a series of closely-spaced heaves or pulses of relatively undifferentiated Kokstad-type magma. The gabbro differentiated in place to form ferrogabbros which chemically closely approximate ferrotholeiite compositions. toidal facies. Residual liquids crystallized as a pegmatoidal facies. A simple fractional crystallization path, modelled on the assumption that the gabbro and ferrotholeiite form a continuous series, indicates that the least evolved ferrotholeiite can be derived from the initial gabbro composition by the fractionation of major amounts of plagioclase and pyroxene but lesser amounts of olivine. Crystallization and removal of magnetite and other Fe-oxides were relatively more important during the later stages of differentiation. The variation of major- and trace-elements in tholeiitic Karroo magma under conditions of strong differentiation at Birds River serves as a framework for the regional study of the geochemistry of other Karroo dolerites and volcanics of the north-eastern Cape. New geochemical data are presented for a sample of thirty chilled and coarse-grained Karroo dolerites collected throughout the north eastern Cape. For the most part, the chilled dolerites are relatively undifferentiated and the average composition differs only slightly from that determined by Walker and Poldervaart (1949). Variation diagrams reveal the steady increase in Si, Al, Ca, Na, K and P and the residual trace elements Ba, Zr, Rb, Y, Nb and Zn with increasing differentiation of the dolerites from more basic types. The concentrations of K, Ba and Rb are highly variable in some Karroo dolerites while new data suggest that Nb levels in the dolerites are low, being generally less than 10 ppm. The strong variation of the K-related elements (K, Ba and Rb) as well as the large ranges determined for certain inter-element ratios, such as K/Rb, Zr/Nb and K/Zr in the chilled Karroo dolerites, suggest that factors other than fractional crystallization processes need to be considered to account for individual variations. Little correlation exists between petrographic type as defined by Walker and Poldervaart (1949) and geochemical character. New geochemical data are also presented for ten Karroo basaltic lavas from the lowermost horizons of the lava sequence exposed in the Barkly East area. Major- and trace-element data indicate that these earliest Karroo extrusives are on average enriched in Si and Rb but depleted in Co and Ni when compared with the averaged chilled Karroo dolerite. Compared with basalts from Lesotho, the Barkly East basalts are enriched in Si but depleted in Ni and possibly Nb, Cu and V. The andesite is markedly enriched in Si, Na, K, Ba, Sr, Rb, Zr and Nb but depleted in Mg, Ca, V, Ni , Cu, Co and Cr. The subdued rate of Ni depletion and the absence of olivine as a major phenocryst phase in the series basalt to andesite, in the Barkly East area, suggests that differentiation trends may be controlled by the fractional crystallization of orthopyroxene and plagioclase, the two common phenocrysts present in these volcanics. The strong depletion of V and Cu in the andesite may indicate some magnetite removal during fractional crystallization.
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  • Date Issued: 1976

Aspects of the woman in art

  • Authors: Loubser, Annette
  • Date: 1976
  • Subjects: Women in art
  • Language: English
  • Type: Thesis , Masters , MFA
  • Identifier: vital:2485 , http://hdl.handle.net/10962/d1012784
  • Description: Woman has been depicted in all mediums throughout the ages, although her image and content have always taken on varying interpretations. Beauty has always been epitomized in the human figure - from an inexhaustible longing for perfection. Naturally her feminineaspects and her unconscious awareness of the rythms of nature made her central to the making of myths. She was depended upon as the Earth Mother - the creator and preserver of the species. And her mysteries reverberated throughout the ages. The discovery of the earliest Aurignacian Head (20,000 B.C) [Fig. 2] reiterates this. She is not only woman but also prophetess. Chap. 1, p. 2.
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  • Date Issued: 1976

Bacterial degradation of the acaricide amitraz

  • Authors: Baker, Penelope Bridget
  • Date: 1976
  • Subjects: Acaricides , Biodegradation , Gas chromatography , Bacteriology -- Cultures and culture media
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4099 , http://hdl.handle.net/10962/d1009498
  • Description: This thesis describes dip tank field trials and laboratory investigations on the acaricide Amitraz. Amitraz is a triazapenta- diene compound which is relatively unstable in fouled dip washes. The field trials were conducted on the farm Sea View according to the "Total Replacement Method" and on the farm Sea Ways according to the "Lime Stabilization Method" of dipping. The results of these trials showed that Amitraz was stable in clean dip washes, and under conditions of high pH resulting from the addition of slaked lime to the dip wash. Using mixed bacterial populations optimum conditions for degradation of Amitraz in the laboratory were determined. Bacterial cultures degraded Amitraz most efficiently in media supplemented with yeast extract or with a high content of sterile cattle faeces. Amitraz concentrations were determined by gas chromatography. A culture. efficient at degrading Amitraz was enriched from a dip tank sludge inoculum. From this culture ten bacterial isolates were identified; nine of these were of the genus Pseudomonas and one was an Achromobacter sp. Experiments with both mixed and pure cultures demonstrated that bacterial degradation of Amitraz was by the process of co-metabolism. The existence of four degradation products was shown using thin layer chromatography. Tentative identification of two of the products was made.
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  • Date Issued: 1976

Brian Bradshaw

  • Authors: Hogge, Rosemary
  • Date: 1976
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2506 , http://hdl.handle.net/10962/d1016168
  • Description: One assumes that Brian Bradshaw's career in art had been decided upon at an early age, but in fact it was not so. After he had attended the Canon Slade Grammar School in Bolton, his father suggested various options, some of them interesting, like becoming a veterinary surgeon, but that was rejected because although the boy liked 'putting things right' he didn't savour 'cutting things up'. For the same reason he couldn't follow the family tradition on his mother's side and become a doctor. Nor was his wish to become a sea-captain treated with any seriousness, although he thinks with nostalgia of life at sea; and he is pleased he didn't take up forestry because, although he loves the land and admires the art of designing the great gardens and parks which surrounded the Georgian and Regency houses of the 18th Century, he is appalled by the artificial mess they're making of the land now. So in that interim period before being conscripted, they suggested at home that he spend a few months at the Bolton Municipal School of Art under the guidance of Mr. John R. Gauld, and so his course was set for the future. He studied there for three years and was successful in obtaining the "drawing" and "pictorial design" certificates of the Ministry of Education, before joining His Majesty's Forces in 1942.
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  • Date Issued: 1976

Changes in the aerobic saprophytic microbial flora during biltong production with special reference to the micrococcaceae

  • Authors: Taylor, M B
  • Date: 1976
  • Subjects: Micrococcaceae , Saprophytism
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4120 , http://hdl.handle.net/10962/d1013308
  • Description: Ninety-four presumptive Micrococcus and Staphylococcus strains isolated from both commercial beef biltong and game biltong, were identified using a scheme based on the system used by Baird-Parker. The changes occurring in both the aerobic, saprophytic microbial flora and the environmental factors, during conversion of beef to biltong, were examined. The predominantly Gram-negative, halo-sensitive flora initially present on the meat, was replaced by Gram-positive, halo-tolerant staphylococci and micrococci, which form the dominant component of the microflora of the final product. This replacement was attributed to changing environmental factors, principally to the increasing sodium chloride concentration and associated decline in water activity. The presence of the antifungal antibiotic, pimaricin, during processing did not influence the bacterial flora of the product. However, the addition of potassium sorbate altered the microbial profile of the product significantly. The presence of these two preservatives, at the concentrations used, could not be detected organoleptically. The importance of the saprophytic microflora of the product ln relation to the environmental factors during processing, is also discussed.
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  • Date Issued: 1976

Drummer Hodge : the poetry of the Anglo-Boer War (1899-1902)

  • Authors: Van Wyk Smith, Malvern
  • Date: 1976
  • Subjects: War poetry -- History and criticism South African War, 1899-1902 -- Literature and the war South African War, 1899-1902 -- Art and the war
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:2252 , http://hdl.handle.net/10962/d1003919
  • Description: From Preface: This is not a history of the Boer War; nor is it an exclusively literary study of the poetry of that war. If the work that follows has to be defined generically at all, it may be called an exercise in cultural history. It attempts to assess the impact of a particular war on the literary culture, especially the poetry, of both the participants and the observers, whether in South Africa, in Britain and the rest of the English-speaking world, or in Europe. An assumption made throughout this study is that war poetry is not only verse written by men who are or have been under fire. Just as 'War poetry is not to be confused with political, polemical, or patriotic verse, although it can contain elements of all of these, so it is also the work of observers at home as much as that of soldiers at the front. It follows that I have not allowed myself the academic luxury of selecting, on the basis of literary merit only, a handful of outstanding war poems for rigorous analysis and discussion. "Doggerel can express the heart" wrote one of these late-Victorian soldierly versifiers, and I have roamed widely in the attempt to assemble the material which, I believe, records the full range of the impact that the Boer War made not only on Briton and Boer, but on the worId at large. A major thesis of this study is that the Boer War marked the clear emergence of the kind of war poetry which we have come to associate almost exclusively with the First World War. Poems in the style and spirit of "The Charge of the Light Brigade" were written in profusion, but the work which serves as this study's masthead, Hardy's "Drummer Hodge," clearly has --like many of its contemporaries-- more in common with Owen's verse than with Tennyson's. The reasons for the appearance of such poetry are discussed in Chapter 1; the rest of the book provides the evidence of it.
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  • Date Issued: 1976

Farm labour in the Eastern Cape, 1950-1973:

  • Authors: Antrobus, Geoffrey G
  • Date: 1976
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/142850 , vital:38123 , http://opensaldru.uct.ac.za/bitstream/handle/11090/465/1976_antrobus_sflcp20.pdf?sequence=1
  • Description: The purpose of this paper is to, survey the farm labour conditions in the Eastern Cape over approximately two decades and to note some of the conditions of service and the attitudes of employers, and the changes which have occurred in employment and wages paid. The main source for the latter period, and in particular 1973, is a farm labour survey conducted in conjunction with E.A. Thomson in the Eastern Cape. The survey relied entirely on the willingness of members of farm study groups and Farmers' Associations as well as interested individuals for its completion. Of the approximately 1020 pre-coded questionnaires which were posted to farmers throughout the Eastern Cape in June 1973, 303 were returned of which 299 were suitable for analysis.
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  • Date Issued: 1976

From frontier to midlands: a history of the Graaff-Reinet district, 1786-1910

  • Authors: Smith, Kenneth Wyndham
  • Date: 1976
  • Subjects: Graaff-Reinet (South Africa) -- History
  • Language: English
  • Type: Book , Text
  • Identifier: http://hdl.handle.net/10962/2656 , vital:20313 , ISBN 0949980730
  • Description: The study of local history in South Africa is still in its infancy and has not been accorded the same recognition as elsewhere. There is no convenient manual to guide the would-be local historian of the Cape. There are few models that provide an insight into the main problems encountered by the local historian of a Cape community. In such local histories as exist, attention has been focussed predominantly on the foundation and physical growth of towns, the naming of streets, the establishment of schools and hospitals. Many of these accounts were written for publicity purposes or to commemorate the founding of towns. Although there is no history of the Dutch Reformed Church in Graaff-Reinet, the history of local congregations of the Dutch Reformed Church has generally been well covered in the form of Gedenkboeke and other studies. These frequently have a particular relevance as many towns such as Burgersdorp and Colesberg were founded as a result of the initiative of the church. Preface. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
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  • Date Issued: 1976

Geology of the Elisenheim area, Windhoek district, South West Africa, with special reference to the Matchless amphibolite belt

  • Authors: Finnemore, S H
  • Date: 1976
  • Subjects: Matchless Copper Mine (Namibia) , Geology, Structural -- Namibia , Amphibolite -- Namibia , Geology -- Namibia
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5053 , http://hdl.handle.net/10962/d1011864
  • Description: The Elisenheim area is situated just north of Windhoek within the Windhoek Formation of the Swakop Subgroup and is underlain by monotonous succession of semi-pelitic schists with intercalations of amphibolite, talc schist, graphitic schist and marble. Petrographic studies on units of the Matchless amphibolite which outcrop in the south of the property, have resulted in the recognition of three different types of amphibolite, namely, epidote amphibolite, porphyroblastic amphibolite and chlorite-amphibole schist. Amphibole porphyroblasts generally display patchy and zonal intergrowths of hornblende and actinolite which are indicative of non-equilibration during prograde metamorphism. Talc schists have been mapped in the north of the property. All lithotypes have undergone three phases of deformation (Fl, FZ, F3) which terminated with the faulting which underlies the Klein Windhoek, Dobra, Tigenschlücht and Kuruma rivers. Medium grade regional metamorphism accompanied F 1, F Z and F 3 and outlasted the latter. Mineral assemblages throughout the area are those of the amphibolite facies and P, T conditions prevailing during metamorphism are estimated to have been at least 5 kb at ~ 550° C. Petrochemical evidence indicates that the Matchless amphibolites are igneous in origin and genetically related to the ultrabasic talc schists. They are similar in composition to oceanic tholeiites and are thought to have been extruded subaqueously.
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  • Date Issued: 1976

Grazing sequence pattern and species selection by cattle in the Dohne sourveld

  • Authors: Daines, Thomas
  • Date: 1976
  • Subjects: Grasses -- Research -- South Africa -- Cape of Good Hope , Grasses -- South Africa -- Cape of Good Hope -- Identification , Grazing -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4257 , http://hdl.handle.net/10962/d1010955
  • Description: A detailed investigation into the harvesting of the standing grass crop within camps by cattle showed the following: 1. Cattle have a definite order of preference for the components of the Dohne Sourveld grass sward. The most palatable species in order of preference (based on Corrected Species Importance rating) are Themeda triandra, Tristachya hispida, Andropogon appendiculatus, Alloteropsis semialata and Heteropogon contortus. The least preferred species is Elionurus argenteus. 2. The key species, which is defined as the most abundant and productive palatable species, has been identified as Themeda triandra. 3. In harvesting the grass crop, cattle not only have a set preference for species, but also have a set grazing sequence pattern. This can be divided into three main phases. On entering the camp the animals first select the species of their choice, "creaming" these plants (grazed less than 50%) to obtain the most nutritious feed. In their daily search for food they spread their grazing over an increasingly wider area and over a wider range of species. When they can no longer obtain their daily requirements from this "creaming" operation of the more preferred species they return to the most preferred species , which are then heavily grazed (more than 50%) producing the common pattern of area grazing within a camp. These areas increase in size as the cattle graze down the species of their choice, moving to less preferred species as soon as they can no longer obtain their daily intake requirements from the more preferred species. Finally when they have no alternative they graze the least preferred species. 4. Increasing the stocking density does not alter the grazing sequence pattern or change the order of preference for the component species in the sward. It only increases the rate of utilization of the more preferred species and the various phases in the grazing sequence pattern are reached more rapidly. 5. At higher stocking densities the palatable species are more evenly utilized than at lower stocking densities. 6. Cattle graze a greater variety of species when the sward is young and actively growing. As the maturity of the sward increases the cattle concentrate on the more preferred species and are more selective in their grazing. However, their order of preference remains the same. Species that are highly preferred early in the season retain their ranking when the sward is mature. The only exception to this rule is Alloteropsis semialata. Early in the growing season this species is high on the preference list, but as it matures less is taken until when fully mature, it is rejected by cattle. 7. Elionurus argenteus is the least preferred of all the species in the Dohne Sourveld. Cattle will graze this plant as a last resort when grazing a camp early in the season, but reject the plant when it is fully mature. 8. To retain vigour and production of the Dohne Sourveld results of this investigation support the view that grazing management should be based on the principle of controlled selective grazing. Having shown that the more preferred species are over-utilized when attempting to utilize the least preferred species any grazing management that calls for total utilization of all standing vegetation should be rejected. 9. The results of this investigation supports a multicamp system for the Dohne Sourveld where high stocking densities are employed. This will result in the rapid and even utilization of the more preferred species. Management should be based on short period of stay and long period of absence. Cattle should be moved as soon as the key species have been well utilized, but not overgrazed. Cattle should only be returned to the camp when key species have made adequate regrowth following grazing. 10. A method, that is simple to use, is proposed for determining utilization of the veld and key species at different times of the year using the relationship between percentage of ungrazed plants and utilization of the sward and of Themeda triandra, the key grazing species in the sward. 11. Results show that when rested camps are grazed after May, the number of Themeda triandra inflorescences are drastically reduced. Veld that is specifically rested for the production of Themeda triandra seed should be rested from March of the year preceding expected seeding.
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  • Date Issued: 1976

Pre-release studies on Zophodia Tapiacola (Dyar) (Pyralidae : Lepidoptera) : a biological control agent against jointed cactus, Optuntia Aurantiaca Lindley

  • Authors: Hoffmann, John Hugh
  • Date: 1976
  • Subjects: Pyralidae , Lepidoptera , Cactus , Weeds -- Biological control , Opuntia
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5857 , http://hdl.handle.net/10962/d1012320 , Pyralidae , Lepidoptera , Cactus , Weeds -- Biological control , Opuntia
  • Description: Jointed Cactus, Opuntia aurantiaca Lindley (see frontispiece), is the most important weed plant in South Africa, infesting approximately, 1,2 X 10¹° M² and costing approximately R240 000 per annum. Tordon herbicide effectively kills jointed cactus bushes to which it is applied. However, apart from being expensive and damaging to beneficial vegetation, spray programmes have not successfully controlled the weed because most small O. aurantiaca plants are impossible to detect in the field. Biological control may provide a solution to the problem. Two insects, the cochineal bug, Dactylopius austrinus De Lotto and the pyralid moth, Cactoblastis cactorum Berg., already exercise a degree of control over the weed. The introduction into South Africa of other natural enemies such as Zophodia tapiacola (Dyar) from Argentina, South America, may reduce the density of jointed cactus to below an acceptable economic threshold. Any insect considered for release should not colonise and destroy beneficial plants of which the culivated spineless cacti are the most vulnerable. Pre-release studies on Z. tapiacola have shown that it can only colonise a few species of low growing cacti and that it will not damage the large spineless cacti or other desirable plants. Further, the moths are relatively fecund and each larva destroys significant amounts of O. aurantiaca during its development. Consequently, Z. tapiacola is not only considered safe for release but it has the potential to act as a successful biological control agent of O. aurantiaca in South Africa.
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  • Date Issued: 1976

Psychology in the second person : inaugural lecture delivered at Rhodes University

  • Authors: Kruger, Dreyer
  • Date: 1976
  • Subjects: Psychology -- United States -- Philosophy
  • Language: English
  • Type: Text
  • Identifier: vital:645 , http://hdl.handle.net/10962/d1020714 , ISBN 0949980706
  • Description: Inaugural lecture delivered at Rhodes University , Rhodes University Libraries (Digitisation)
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  • Date Issued: 1976

Reaction phenomena between Karroo Dolerite and cave sandstone xenoliths in the Bird's River complex

  • Authors: Kenyon, A K
  • Date: 1976
  • Subjects: Volcanic ash, tuff, etc , Igneous rocks -- Inclusions , Sandstone
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4996 , http://hdl.handle.net/10962/d1005608
  • Description: Mapping of the north-eastern portion of the Bird1s River Complex revealed that two large xenoliths composed of pyroclastic rocks and sandstone of the Cave Sandstone Stage have reacted with the dolerite. All the reaction phenomena normally associated with Karroo Dolerite are encountered. These are: (a) Metasomatism during the stage of iron enrichment of the dolerite with the production of a pyroxene-plagioclase metasomatic granophyre (b) Metasomatism during the stage of alkali enrichment of the dolerite with the production of a potassium feldspar adinole C c) Assimilation 'vi th the production of contaminated doleri tes Cd) Fusion 'vi th the production of glassy rocks including buchi tes (e) The production of rheomorphic veins
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  • Date Issued: 1976
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