The endocoprid dung beetles of southern Africa (Coleoptera: Scarabaeidae)
- Authors: Davis, Adrian L V (Adrian Louis Victor)
- Date: 1978
- Subjects: Dung beetles -- Ecology , Dung beetles -- Africa, Southern
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5845 , http://hdl.handle.net/10962/d1011030 , Dung beetles -- Ecology , Dung beetles -- Africa, Southern
- Description: The biology and ecology of the endocoprid dung beetles of the Aethiopian zoogeographic region has been studied in the field and laboratory. Work has centred mainly on Oniticellus planatus and O. formoaus although infomation has also been supplied on O. egregius, O. pictus and Tragiscus dimidiatus. The taxonomy of Onticellus (s.str.) and Tragiscus has been discussed with the recommendation that O. planattus and O. pseudaplanatus be synonymised. It has been suggested that endocoprid distribution is chiefly controlled by temperature, rainfall and the density of suitable large dung masses. On the basis of distribution it has been suggested that the taxonomic status of the subspecies of O. pictus should be reviewed. Endocoprids (genus Oniticellus (s.str.) are found throughout the warmer regions of Africa and Asia. Tragiscus is found only in Africa. Methods are described for monitoring endocoprids in the field, for distinguishing freshly emerged from older specimens, and for breeding endocoprids under laboratory conditions. It has been shown that endocoprids breed within or just beneath large dung masses unlike most other members of the Scarabaeinae which actively bury dung and construct the their broods at depth in the soil. It has been shown that there is a restriction of breeding sites available to endocoprids due to the removal of dung by the Scarabaeinae beetles and the limited space available within dung pads. This has resulted in low endocoprid population numbers, a disadvantage, which has been countered by highly specialised but opportunistic breeding habits. The requirements of dung plasticity have limited the time available for breeding activity by most endocoprids (excluding O. egresius) so that both the reproductive system and the reproductive behaviour (cf. O. planatus) are geared to rapid egg and brood production. Large numbers of follicles are able to be produced over a short period. In the probable absence of feeding, this has possibly been allowed by the involvement of a well developed fat body. The broods are tended by the parent female during larval development and the follicles are gradually resorbed, probably to prevent starvation. Ovarian recovery is rapid once feeding recommences. Behavioural mechanisms have developed which boost the number of broods constructed and the rapidity with which they are produced. The duration of endocoprid colonisation and the timing of arrival at dung is shown to be related to the rate of pad desiccation which is chiefly controlled by temperature and degree of dung removal by other dung beetles. Precipitation may also play a part. Predation by vertebrates and other insects has been noted and a number of mechanisms are described which are probably protective. Two insect parasitoids of O. formosus larvae have been recorded. The potential use of endocoprids in the Australian dung and fly control project has been discussed and it is recommended that their introduction be considered of low priority. It is suggested that the endocoprids evolved from Euoniticellus type ancestors and that their behaviour complex nidification developed in response to harsh environmental factors, chiefly the danger of desiccation and competition for dung with other dung beetles. From a consideration of brood and brood chamber construction it is suggested that O. egresius is a relatively unspecialised endocoprid which may retain dry season aestivation and has not evolved much further than its probable Euoniticellus type ancestor. The broods are coated in clay and abandoned soon after construction. Greater specialisation is shown by O. planatus and O. formosus which exhibit brooding behaviour, increasing longevity, more specialised brood protection, increased potential fecundity and continuous activity throughout the year. O. formosus shows greater specialisation in brood production than O. planatus. Greatest specialisation is found in T. dimidiatus which exhibits a precise brooding period and low egg production. Brood construction is of a similar degree of specialisation to that of O. formosus. Activity is also continuous throughout the year. The comparative biology of the five southern African endocoprids is summarised in Table 35. Summary, p. 129-131.
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- Date Issued: 1978
A new species of Tropheus (Pisces: Cichlidae) from Lake Tanganyika
- Authors: Axelrod, G S (Glen S.) , Rhodes University. J.L.B. Smith Institute of Ichthyology
- Date: 1977-11
- Subjects: Cichlids , Tropheus , Freshwater fishes -- Tanganyika, Lake
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/69803 , vital:29581 , Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB)) Periodicals Margaret Smith Library (South African Institute for Aquatic Biodiversity (SAIAB))
- Description: Online version of original print edition of the Special Publication of the J.L.B. Smith Institute of Ichthyology; No. 17 , Tropheus polli, a sp. nov. (Pisces: Cichlidae) from Lake Tanganyika, is described and compared with T. moorii Boulenger 1898, T. annectens Boulenger 1900, T. duboisi Marlier 1959, T. brichardi Nelissen & Thys 1975, and T. moorii kasabae Nelissen 1977. Included are detailed morphometric data with a figure and colour plate, a lower pharyngeal bone description with electron micrograph scans, and a type locality map.
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- Date Issued: 1977-11
A comparison between the views of Jonathan Edwards and John Wesley regarding the sovereignty of God
- Authors: Robertson, Alan Charles
- Date: 1977
- Subjects: Edwards, Jonathan, 1703-1758 , Wesley, John, 1703-1791 , Free will and determinism , Predestination -- History of doctrines , God -- Omniscience -- History of doctrines , Atonement
- Language: English
- Type: Thesis , Bachelor , BDiv
- Identifier: vital:1268 , http://hdl.handle.net/10962/d1013067
- Description: The views of Edwards and Wesley regarding the sovereignty of God present a puzzle. On the face of things, both were successful evangelists while both held contrary doctrines of sovereignty. Does this mean that the doctrine of sovereignty is irrelevant? This thesis argues that the doctrine of sovereignty is crucial in evangelism and revival, and that the views of Edwards and Wesley regarding the sovereignity of God were in fact very similar. A useful framework for showing this is the Five Points of Calvinism, as well as the doctrines of justification by faith and the omnipotence of God.
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- Date Issued: 1977
A cross-cultural study of interpersonal distance and orientation schemata
- Authors: Edwards, David J A
- Date: 1977
- Subjects: Personal space -- Testing Orientation (Psychology) Cross-cultural studies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3206 , http://hdl.handle.net/10962/d1011743
- Description: Expectations about interpersonal distance during social encounters (distance schemata) and body orientation (orientation schemata) were investigated among White English-speakers and Xhosa groups which included illiterate traditionalists (Reds), poorly educated urban dwellers, and highly literate students and nurses. In a series of six experiments a doll placement task was used in which subjects represented dyadic encounters by placing pairs of standing dolls. For each situation represented the responses of each group of subjects were summarised in the form of a profile which showed the mean of the distance and three angle measures (IPOS profile). Independent variables included culture of subject, type of situation represented (friendly encounter, quarrel, accusation and denial, request) and the sex, age or relationship of the persons represented. In the culminating experiment (Experiment 6), females from three Xhosa groups (Reds or XR, poorly educated urban or XU, and urban nurses or XN) made twenty-three placements. In some respects the schemata of the four groups were very similar, while in others both distance and orientation schemata were a function of cultural group. The experiments allowed an assessment of the validity of the doll placement method to be made, and results were discussed in terms of the effects on interpersonal distance and body orientation of cultural norms concerning the showing of respect and the nature and strength of the emotions present in the various types of situation. It was concluded that with cultural movement away from the traditionalist pattern the schemata of the urban Xhosa showed a transition towards those found among the Whites in some respects. However, while the schemata of the XN group showed features of both those of the XR and White groups, those of the XU group showed features found in neither which seemed to reflect the insecurity of the cultural milieu of the urban poor.
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- Date Issued: 1977
A history of the Xhosa, c1700-1835
- Authors: Peires, J B (Jeffrey B)
- Date: 1977
- Subjects: Xhosa (African people) -- History
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2611 , http://hdl.handle.net/10962/d1013024
- Description: The boundaries of the territory occupied by the Xhosa fluctuated considerably, but in the period 1700-1835 they did not often extend west of the Sundays River, or east of the Mbashe River, along the coastal strip which separates the escarpment of South Africa's inland plateau from the Indian Ocean. It is an area of temperate grassland, permitting the cultivation of cereals and light crops, such as maize, millet, tobacco and pumpkins but better suited to stock-farming than intensive agriculture.
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- Date Issued: 1977
A linguistic account of quantifiers in English and their place in the development of some modern approaches to syntax and semantics
- Authors: Aldridge, Maurice Vincent
- Date: 1977
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:20966 , http://hdl.handle.net/10962/5707
- Description: From Introduction: I should make it clear from the outset that I have no intention of trying to construct a calculus for the quantificational system of English as a natural language. My interests are purely linguistic with special emphasis on that part of the discipline traditionally known as semantics. Thus, although I offer a miniature survey of the development of quantificational studies in Philosophy in Chapter One, and have frequent recourse, in other charters, to observations made by philosophers, especially Quine, I make no attempt whatever to emulate the logicians by constructing such things as rules of inference. I have also tried to avoid symbolic representations except in those cases in which they show up aspects of semantic structure very clearly, and where I have symbolised, I have alternated between the systems of Quine and Peano-Russell, selection in each instance being determined by judgements regarding clarity.
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- Date Issued: 1977
A study of the distribution of nutrients during the growth of cayenne pineapples under field conditions
- Authors: Fowler, William Mackenzie
- Date: 1977
- Subjects: Plants -- Nutrition , Pineapple -- Crop yields , Growth (Plants) , Field Crops -- Nutrition
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4260 , http://hdl.handle.net/10962/d1011888 , Plants -- Nutrition , Pineapple -- Crop yields , Growth (Plants) , Field Crops -- Nutrition
- Description: The purpose of this study was to determine the uptake and distribution of nutrients during the growth of the Cayenne cultivar of Ananas comosus (L) Merr under field conditions in the Eastern Cape. The study was also done to help explain the apparent drop in the nutrient levels in the basal section of the "D"- leaf of the pineapple plant during the winter months and to determine the best part or parts of the plant to sample in order to measure the nutrient status of the pineapple plant at any stage of its growth. The investigation was conducted by selecting a plot within a production land on two farms in the pineapple growing region of the Eastern Cape. Plants were sampled from each plot at regular intervals from planting of the pineapple tops until the harvesting of the fruit of the first plant crop. Plant growth was measured and the nutrient concentrations in each section of the plant were determined. The total amounts of nutrients for each plant part were calculated and the nutrient uptake was compared and plotted on distribution diagrams.
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- Date Issued: 1977
A study of the rabbit eye test system to determine the activity of acidic non-steroidal anti-inflammatory agents
- Authors: Wiseman, Ian Charles
- Date: 1977
- Subjects: Nonsteroidal anti-inflammatory agents , Anti-inflammatory agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3855 , http://hdl.handle.net/10962/d1013276
- Description: From introduction : "Inflammation per se, has been defined sufficiently to permit a rational approach to the search for drugs that modify this process, but satisfactory animal models for most rheumatoid diseases are not available". (Swingle 1974) In the search for new meaningful procedures for the detection and evaluation of anti-inflammatory drugs, the rabbit eye as a test system was studied.
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- Date Issued: 1977
A taxonomic study of the Genus Lethrinops Regan (Pisces: Cichlidae) from Lake Malawi: part 1
- Authors: Eccles, David H , Lewis, Digby S C
- Date: 1977
- Subjects: Lethrinops -- Malawi, Lake -- Classification , Haplochromis -- Malawi, Lake -- Classification
- Language: English
- Type: Text
- Identifier: vital:14988 , http://hdl.handle.net/10962/d1018956 , ISBN 949980854 , Ichthyological Bulletin of the J.L.B. Smith Institute of Ichthyology; No. 36
- Description: Haplochromis micrentodon Regan is transferred to the genus Lethrinops and redescribed. Two new species of Lethrinops which, like the above, are characterised by the possession of lower pharyngeal bones bearing close pavements of slender blunt-tipped teeth are described. , Rhodes University Libraries (Digitisation)
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- Date Issued: 1977
Aerogramme from Cheshire, England to Pretoria
- Date: 1977
- Subjects: Butler family -- Photographs
- Type: Text
- Identifier: http://hdl.handle.net/10962/30217 , vital:23823 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , PIC/M 6352
- Description: A letter from Rev Dr and Mrs S H Russell about their stay in Cheshire, England, written to Miss Jean Irons from Val de Grace, Pretoria, South Africa, dated 6th July 1977.
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- Date Issued: 1977
African art and myth
- Authors: Till, C M
- Date: 1977
- Subjects: Art, African , Art and mythology , Mythology, African
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2494 , http://hdl.handle.net/10962/d1013306
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- Date Issued: 1977
An ideographic study of bisexuality
- Authors: Parker, Peter Burns
- Date: 1977
- Subjects: Bisexuality -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3036 , http://hdl.handle.net/10962/d1002545 , Bisexuality -- Psychological aspects
- Description: This research can be seen as being a step towards an answer to the question "what is bisexuality?". Such an aim, however, appears to be a contradiction in terms. Surely we must be assuming an answer by asking the question. How can one ask a question such as “what is bisexuality?", if we have no conception of what the word bisexuality means? Owing to the lack of information in the literature with which to answer the question of this study, it was decided that an in-depth study of one individual would be a most suitable starting point to begin an illumination of the themes which lie in the depths of this complex phenomenon . An in-depth study would hopefully do this without lapsing into the stereo - typed ways of thinking and terminology that could eventuate from a more populous and necessarily more superficial approach (Kotze 1974). Arising out of the prevailing conception of human sexuality as comprising two modes of sexual existence - heterosexuality and homosexuality only, the idea of bisexuality is hardly to be found in the ordinary man's or, for that matter, the psychologist 's, conceptual frameworks. The only extensive work that has been undertaken to date which uncovers, to a certain extent, the nature of human sexuality, is that of Kingsley (1948 and 1953). Although it must be kept in mind that this research is dated, it certainly does indicate that perhaps it would not be unrealistic to begin to reconceptualise our views on man's sexual mode of existence . This thesis presents the case of a man, who, according to our present view, does not exist.
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- Date Issued: 1977
An investigation of plant-derived cardiac glycosides as a possible basis for aposematism in the aphidophagous hoverfly Ischiodon aegryptius (Wiedemann) (Diptera: Syrphidae)
- Authors: Malcolm, Stephen Baillie
- Date: 1977
- Subjects: Diptera , Syrphidae , Aphidophagous insects , Predatory animals , Insect-plant relationships , Insect pests -- Biological control , Insects as carriers of disease
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5864 , http://hdl.handle.net/10962/d1012798 , Diptera , Syrphidae , Aphidophagous insects , Predatory animals , Insect-plant relationships , Insect pests -- Biological control , Insects as carriers of disease
- Description: The chemical defences of insects against predators are either passive or aggressive. Passive defence is achieved through crypsis, and aggressive defence is maintained by a conspicuous or 'aposematic' (Poulton, 1890) appearance that advertises some noxious quality of the insect harmful to a predator. Aposematism is mutually beneficial to both the bearer and its predator, whereas crypsis only benefits the prey species. It is therefore not surprising that the fascinating array of chemical defences in insects is both diverse and widespread (Roth and Eisner, 1962). Intro. p. 1.
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- Date Issued: 1977
An investigation of the relationship between acculturation, n achievement and n affiliation in Owambo
- Authors: Steyn, Daniël Marthinus
- Date: 1977
- Subjects: Ovambo (African people) , Acculturation -- Namibia , Achievement motivation , Affiliation (Psychology)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3241 , http://hdl.handle.net/10962/d1013295
- Description: The contents of this thesis were mainly determined by the traditional methodological requirements for a thesis of this nature. However a need was felt to include a somewhat expanded survey of the interrelationship between anthropology and psychology. This "need" developed during a review of the above-mentioned interrelationship especially when we found that the historical interaction between these two disciplines had never been followed from the earliest times to the present. Furthermore, although different writers have treated different aspects of this interaction, not one could be found that had treated all the different angles of the relationship. Thus although it is a well known fact that there is a prominent relationship between these two disciplines this was found to be quite inadequately documented. Furthermore, it is usually discussed from either a psychological or an anthropological viewpoint. The hazy view of the interrelationship between these two disciplines is naturally a frustrating situation for any researcher in this field - especially one who would prefer to have a view of the position of his research within the wider panorama of research surrounding it. Intro., p. 1.
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- Date Issued: 1977
Art and power : an investigation into the effect politics, the church and economics have had on the content of a work of art and the development of art in general
- Authors: Heydenrych, Albert B
- Date: 1977
- Subjects: Art and religion , Politics in art , Art and industry , Art and state
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2499 , http://hdl.handle.net/10962/d1013390
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- Date Issued: 1977
Aspects of imagery, syntax and metrics in the poetry of George Herbert
- Authors: Edgecombe, Rodney Stenning
- Date: 1977
- Subjects: Herbert, George, 1593-1633 -- Criticism and interpretation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2294 , http://hdl.handle.net/10962/d1011613 , Herbert, George, 1593-1633 -- Criticism and interpretation
- Description: I intend In this thesis to examine some central features of George Herbert's art - aspects of his imagery syntax and metrics. These topics have been chosen because they encompass large areas of his poetic practice, ramifying as they do into questions of theme, tone and structure. Even a partial. survey of Herbert' s imagery, such as the one I attempt to offer, should enable the reader to judge the range of experience that Herbert brings to bear upon a comparatively circumscribed number of themes, (The "Affliction " poems, for example, are wonderfully diverse, although they have a common thematic centre). A brief examination of the traditions within which Herbert's manipulation of imagery falls should allow one also to judge his resourcefulness, especially in the composites of emblem and symbol he devises on occasion; which in the concluding analyses I attempt to show the structural significance of image patterns in representative poems from The Temple. Thus Chapter I falls into three sections: a brief discussion of emblematic and symbolic traditions together with Herbert 's place in relation to them, a deliberately selective glance over some images (a full examination is far beyond the scope of this thesis), and finally some close analyses of poems in the course of which I try to show the imagery operating as a structural and coordinating device. In Chapter II, I move on to the closely related area of syntax, examining Herbert's formulation of his material, and finding - amongst other things - that there is evidence of "grammatical" imagery where the disposition of a sentence provides a concrete embodiment of the theme. This interrelationship of imagery and syntax (and of imagery and metrics) is a corollory of poetry's organic nature, and in order to stress the mutual collaboration of these features, I have subjected a single poem, "The Flower" to an analysis from three different angles, assuming that each approach will further illuminate the others. All the lyrics would yield riches if treated in this way but my limits of space have naturally precluded so elaborate an undertaking. Even In the analyses of poems that are treated only once, I have been at pains to allow in a glimmering of topics other than that in hand, so as to enlarge the scope of my examination. Although the material in Chapter II is designed to highlight the structural, tonal and thematic effects of syntax in turn, such divisions remain theoretical rather than actual, for they combine almost indivorcibly into a complex whole. Chapter III is patterned like Chapter I in that it moves from a general survey of Herbert's metrics, his rhyme and his stanzaic design, to further close analyses of his metrical procedures in particular lyrics. Both here and in the preceding chapters I have undertaken to look at Herbert's work in close detail, because, as I have already suggested, his is an art of compression, of telescoping a whole range of meanings into the neatest and most compact shape. Given the differences in mode and intention, his poetry often puts one in mind of Jane Austen's fiction - at least in the profundity it achieves within a consciously limited scale and a critical magnifying glass seems to me to be the most apposite aid for such a study as I have undertaken.
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- Date Issued: 1977
Attitude and personal orientation differences between clergy of Anglican and Pentecostal denominations with particular reference to sexual ethics
- Authors: Davies, Alan Bruce
- Date: 1977
- Subjects: Clergy -- Sexual behavior Pentecostalism -- Sexual behavior Anglican Communion -- Clergy -- Sexual behavior Sex -- Religious aspects -- Christianity Christian ethics -- Anglican authors Sexual ethics
- Language: English
- Type: Thesis , Bachelor , BDiv
- Identifier: vital:1247 , http://hdl.handle.net/10962/d1011015
- Description: The introduction provides a concise discussion of the confused condition of our Western sexuality. It is noted that this confusion has also manifested itself in ecclesiastical circles, and that the contribution of the church towards the resolution of 'moral' confusion in this sphere is in fact minimal. The study then proceeds to a more empirical investigation of certain phenomena which might enable us to demonstrate the close relationship which exists between the individual's psychological condition, or 'state of consciousness', and the type of theology or ethics he formulates or adopts. The present study was an investigation designed to determine whether Anglican clergy and Pentecostal pastors differed significantly with regard to theological orientation, level of self-actualization or the degree of flexibility they showed in the application of sexual values. Furthermore we were concerned to discover the inter-relation between these various traits. A third group of ordinands from St. Paul's College (C.P.S.A.) was also incorporated into the study. All forty eight subjects completed a series of tests and questionnaires which were scored according to eighteen different scales relating to selfactualzing traits, theological orientation and the application of sexual ethics. In brief the results showed that the Anglican clergy were significantly more self-actualizing, theologically liberal and more flexible in the application of sexual values than were Pentecostal pastors. Little difference was found to exist as a function of age and education, or between Anglican clergy and ordinands. Furthermore theological conservatism, general conservatism, dogmatism and inflexibility in the application of sexual ethics were all shown to correlate negatively with self-actualization. In the discussion of results the writer attempted to demonstrate the close relationship between the churchman's psychological make-up and the way in which he construes his world and formulates his theology and ethics. In the concluding discussion the writer once again widened the scope of concern in order to demonstrate how the findings of the present study can be fitted into the broader context of the life of the church. It has been suggested that the type of approach adopted by churchmen to problems of sexuality is very much determined by their psychological make up. Hence in this sense both the status of the church in modern society and the degree to which the church can assist in the resolution of our culture's problems in the field of human sexuality, is greatly dependent upon the 'states of consciousness' of our clergy.
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- Date Issued: 1977
Categories of experience amongst the Xhosa : a psychological study
- Authors: Schweitzer, Robert David
- Date: 1977
- Subjects: Xhosa (African people) -- Psychology
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3237 , http://hdl.handle.net/10962/d1013172
- Description: Transcultural studies of psychological states may be seen as falling within two schools, one adopting a position in which universal criteria of "mental health" are assumed, the other a cultural relativist position in which phenomena are understood in terms of the context in which they occur. The present study, in adopting the latter position, examines categories of experience amongst the Xhosa in terms of their meaning within Xhosa cosmology. The thoughts and practices of a Xhosa Iqgira (diviner) were extensively examined using an idiographic approach. This was corroborated by in-depth interviews with his consultees who were undergoing the categories being studied. Three categories, thwasa, phambana and amafufunyana are explicated. Thwasa is seen to be related to the individual- shade communion. Phambana is predominantly related to custom and witchcraft. Amafufunyana is related to disharmonious interpersonal situations within the community. The universalist position, derived from descriptive psychiatry, has often viewed the mental status of amaqgira {diviners) as neurotic or even psychotic. This finding is not supported in the present study. The implications of the research for community mental health in Southern Africa are discussed.
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- Date Issued: 1977
Colour vision of the citrus psylla Trioza erytreae (Del Guercio) (Homoptera: Psyllidae) in relation to alightment colour preferences
- Authors: Urban, Alan Joseph
- Date: 1977
- Subjects: Trioza , Homoptera , Jumping plant-lice , Color vision
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5885 , http://hdl.handle.net/10962/d1013286
- Description: The colour vision of adult citrus psylla, Trioza erytreae, was investigated in the laboratory using the behavioural parameters: alightment and walking. Light green flushing leaves (under which the nymphs develop) were significantly preferred, visually, to dark green mature leaves for alightment. Diffuse reflectance spectroscopy showed (when expressed in the parameters of human colour vision) that flush has a very slightly longer dominant wavelength, and roughly double the reflectance and purity. Alightrnent frequency correlated almost equally well with "purity" (as noted by Moericke, 1952 et seq., in "yellow-sensitive" aphids) as with the aphidological colour parameter "long/short ratio" developed by Kennedy et al. (1961). Elucidation of the mechanism underlying the citrus psylla's alightment colour preference was initially attempted with a printed spectrum and several paint series of measured spectral characteristics. It was clear that T.erytreae belongs to the "yellow-sensitive" group of Homoptera, but it was impossible to distinguish which pararneter(s) of colour the psyllids were responding to. Phototactic (walking) response to the individual parameters of colour was therefore measured using a monochromator. The phototactic action spectrum (against wavelength) was tri-modal, with peaks in the yellow-green (YG), blue (B), and ultra= violet (UV). Rate of phototaxis was not influenced by bandwidth (roughly equivalent to purity), but was proportional to intensity (roughly equivalent to reflectance). To investigate the influence of the above three wavelength regions on alightment, use was made of a very simple flight chamber incorporating a target of coloured light. Yellow-green and UV light both independently stimulated alightment . Their effect was additive. Different thresholds indicated distinct YG and UV receptor systems. Blue light alone did not stimulate alightment, and was strongly alightment-inhibitory in combination both with YG and with UV light. On the basis of the above physiological/behavioural findings, a new alightment formula was drawn up for describing the hamopteran's apparent manner of alightment determining integration of surface reflectance. The flush preference and alightment distributions on the series of artificial surfaces were found to correlate slightly more accurately, on average, as well as more consistently, with the new formula than with previously-available colour parameters. These findings are placed in perspective to the literature, and their possible economic relevance is discussed.
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- Date Issued: 1977
Conscientious objection and the concept of worship
- Authors: Moulder, James Edward
- Date: 1977
- Subjects: Conscientious objectors -- Law and legislation -- South Africa , Conscientious objectors -- South Africa , Conscientious objection , Conscientious objection -- Religious aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2749 , http://hdl.handle.net/10962/d1013555
- Description: [Preface] " ... the focus of this inquiry is limited to some of the connections between conscientious objection in South Africa and the worship and imitation of Christ. More specifically, at the most general level this essay is an attempt to explore six questions: What kind of conscientious objection does South African law allow? Why are some conscientious objectors only conscientious noncombatants? Why are some Christians conscientious noncombatants? Is it appropriate to worship Christ? Does Romans 13 undermine conscientious noncompliance? And is there a prescription for servile compliance? These are, however, not the only questions which are raised in this essay. Nor are they the only questions which can and need to be asked. But they are the questions which interest me. In addition, they have not received as much attention as they deserve".
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- Date Issued: 1977