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Oxygen isotope geochemistry of the Mesozoic volcanics of the Etendeka Formation, Namibia

  • Authors: Harris, Chris , Smith, H Stuart , Milner, Simon C , Erlank, Anthony J , Duncan, Andrew R , Marsh, Julian S , Ikin, Nicholas P
  • Date: 1989
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/143272 , vital:38219 , https://doi.org/10.1007/BF00371087
  • Description: The Etendeka Formation volcanics consist of a bimodal association of basalts and quartz latites. Forty three new whole rock oxygen isotope analyses are reported for all the major magma types. All the rocks except a minor suite of dolerites have higher δ18O values than normal mantle. The basic rocks (average of 29=8.8‰) have significantly different δ18O to the acid rocks (average of 10=14.4‰). These data are apparently consistent with previously published petrogenetic models, which propose that the basalts were affected by crustal contamination and that the quartz latites are crustally derived.
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  • Date Issued: 1989

Parallel process placement

  • Authors: Handler, Caroline
  • Date: 1989
  • Subjects: Parallel programming (Computer science)
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4568 , http://hdl.handle.net/10962/d1002033
  • Description: This thesis investigates methods of automatic allocation of processes to available processors in a given network configuration. The research described covers the investigation of various algorithms for optimal process allocation. Among those researched were an algorithm which used a branch and bound technique, an algorithm based on graph theory, and an heuristic algorithm involving cluster analysis. These have been implemented and tested in conjunction with the gathering of performance statistics during program execution, for use in improving subsequent allocations. The system has been implemented on a network of loosely-coupled microcomputers using multi-port serial communication links to simulate a transputer network. The concurrent programming language occam has been implemented, replacing the explicit process allocation constructs with an automatic placement algorithm. This enables the source code to be completely separated from hardware considerations
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  • Date Issued: 1989

Part four of the Rhodes University Skymap Program

  • Authors: Wright, Michael Robert
  • Date: 1989
  • Subjects: Southern sky (Astronomy) Radio astronomy
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5435 , http://hdl.handle.net/10962/d1001988
  • Description: The results of the fourth part of the Rhodes University Skymap Program are presented. The observations cover the area of sky between right ascension 14h00m and 02h30m and declination -26⁰ and + 13⁰ at a frequency of 2.3 GHz. Contour maps of this region, with a resolution of 0.38⁰, are presented. Various methods of reducing the effect of the Galactic disc emission are analyzed. The results demonstrate the effectiveness of one of these methods in the production of a flat base level. The filamentary structure of the North Polar Spur is enhanced and results are obtained which support current theories of the origin of this object. The HII region surrounding Ophiuchi is examined in detail. A number of parameters are derived for the HII region. The spur associated with the HII region S54 is also examined. A listing of 1105 point sources appearing in the maps is presented. The limiting flux density of this listing is 0.5 Jy
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  • Date Issued: 1989

Peace Song

Pesalema 100

Photos convey magic of '60s jazz scene

Physiological and psychophysical factors in the rating of perceived exertion during uphill overground and treadmill running

  • Authors: Olivier, Stephen Chris
  • Date: 1989
  • Subjects: Physical fitness -- Measurement , Physical fitness -- Physiological aspects , Physical fitness -- Psychological aspects , Running -- Testing
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:5161 , http://hdl.handle.net/10962/d1015769
  • Description: The purpose of this study was to examine possible differences between the field and laboratory ratings of perceived exertion (RPE) when the performance and physiological measures for the two conditions were equated. Furthermore, the interactive effects of local, central and overall RPE were examined. Finally, the question of the potential effects of attitudes on RPE was addressed. Eleven well-conditioned adult male marathon runners voluntarily participated in the study. After a period of treadmill habituation, biographical and anthropometric data were collected. This was followed by a VO₂ max test and a speed-matching session at 70% of VO₂ max to determine overground running speed at 3.8% and 7. 5% grade. Subjects then completed an attitudinal questionnaire and ran 4km overground. Finally, the above test was repeated on the treadmill, with the gradient and running speed of the overground condition being replicated. Physiological measures and differentiated RPE were obtained during the final two sessions. There were no physical environmental, task characteristic or performance differences between the overground and treadmill conditions. No heart rate or VO₂ differences were observed between the two conditions, but VE was significantly elevated in the laboratory. Local and overall RPE were significantly higher in the laboratory than in the field, but there was no difference for central RPE. Attitudes were more favourable towards the field than towards the laboratory work task. The results suggest that neither heart rate nor VO₂ are major factors directly influencing the perception of exertion. VE however appears to be a potent central signal mediating RPE. The results also indicate that local factors play a more important role in the perception of exertion than was previously thought. Attitudes towards a work task could possibly mediate the self-reports of exertion. The findings of this study also suggest that RPE are influenced by cognition to a large degree. Finally, environmental cues, or the ambience of a particular working environment, can exert a substantial influence on RPE. Direct perceptual translations from laboratory to field situations may therefore be invalid.
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  • Date Issued: 1989

Plants - yesterday, today, tomorrow? : inaugural lecture delivered at Rhodes University

  • Authors: Botha, Christiaan Edward Johannes
  • Date: 1989
  • Subjects: Botany
  • Language: English
  • Type: Text
  • Identifier: vital:603 , http://hdl.handle.net/10962/d1020672 , ISBN 0868101931
  • Description: Inaugural lecture delivered at Rhodes University. , Rhodes University Libraries (Digitisation)
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  • Date Issued: 1989

POTWA Newsletter - Northern Cape Congress

  • Authors: Post and Telecommunication Workers Association (POTWA)
  • Date: 1989
  • Subjects: POTWA
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/162032 , vital:40750
  • Description: The Northern Cape Region of Potwa held a very vibrant regional congress in Vryburg on the 15 & 16 April 1989. The Congress was characterised by a spirit of comradely self-criticism. This political maturity of the comrades went as far as to give a proper critical analysis of the structures of our organisation. The analysis accepted that the functioning of some of our organisation’s structures is not up to standard. The congress also noted that the participation of the general membership in the activities of the organisation is not satisfactory. As it is typical of matured comrades, the congress realised that such problems are not peculiar to Potwa. Shortcomings such as these are indicative of a huge and growing organisation. Because of this, the comrades explored ways and means of solving these problems. The congress concluded that the opening of a regional office combined with effective usage of our Potwa newsletter would go a long way in solving some of our problems.
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  • Date Issued: 1989

Prayer and Response

Prayer and Response

Prayer Response

Prayer Response

Prayer Response

Prayer Response

Prayer Response

Primêre leerlinge se geskiedenispotentiaal: 'n empiriese ondersoek na senior primêre leerlinge en onderwysers se vermoë om indringende vrae oor 'n historiese gebeurtenis met begrip en insig te beantwoord

  • Authors: Hattingh, Johannes Hendrik
  • Date: 1989
  • Subjects: History -- Study and teaching (Elementary)
  • Language: Afrikaans
  • Type: text , Thesis , Masters , MEd
  • Identifier: vital:1362 , http://hdl.handle.net/10962/d1001428
  • Description: The main aim of this research was to determine the potential of senior primary pupils and serving teachers to understand a text that is concerned with a historical event. A test was written by 136 white standard 3, 4 and 5 pupils from a Cape Province primary school, as well as 32 serving teachers from various other Cape Province primary schools. The test consisted of a text and questions based upon it. The testees had 60 minutes at their disposal to study the text and give written answers to the questions. The historical event explained in the text dealt with the Peasant Uprising that occurred in England in 1381. Eight open-ended questions were asked. The questions were graded according to difficulty and based on the model of Merrit to test the following levels of thought: knowledge, application, inference and evaluation. In the dissertation attention is paid to the following aspects: 1. Background for the research. 2. The most important theoretical aspects that play a role in the process of historical understanding. 3. A statistlcal analysis of the results obtained from the pupils and teachers, with attention to those factors that may have influenced the results e.g. verbal IQ, age, interest, etc. 4. The quality of the teachers' and pupils' answers as well as examples from their work to illustrate certain aspects. 5. The most important conclusions that can be drawn from the research. Based on their answers to the graded questions the pupils were grouped into different levels to ascertain whether a significant pattern would emerge for each standard. It became clear, however, that irrespective of age or verbal IQ the pupils could not consistently be grouped into a specific level or category. The most important conclusions of the research are the following: 1. The ability of senior primary pupils to cope with intellectually stimulating material are underestimated. 2. A variety of factors influenced the results of the pupils, but not one of the factors studied in this research was found to be of significant importance. 3. The average primary teacher do have the potential ability to cope with more difficult historical material than the present factual approach would suggest.
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  • Date Issued: 1989

Procession of the Gifts

Procession of the Word

Ra tsamaya Kwa Kanamo

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