Faculty of Natural and Agricultural Sciences
School of Physical Sciences
Gold Fields Computer Centre
Selected Highlights from Research Findings
A look at online plagiarism. As part of a computer literacy program, a group of first year students at the University were asked to write an essay on Grace Murray Hopper from research they did on the Internet. These students, with very few exceptions, copied and pasted excerpts from various pages they visited without making much effort to read the information presented. In analysing these students' essays, it was found that plagiarism on the Web was widespread, even sites discussing plagiarism plagiarised information.
Contact person: Mr BA Carr.
Information, knowledge and learning. Is the Web effective as a medium for Mathematics teaching? This document is a report on an experiment in which mathematical skills were taught to first year university students using the Web as a method of instructional delivery. Definitions for knowledge, information, learning and teaching were developed. These definitions were then used as the foundation for creating the Web pages used in the experiment. Special attention was paid to the ability of students from previously disadvantaged backgrounds to cope with this method of delivery. Overall, the results obtained by students using this method were slightly better than those of students on the equivalent paper-based course. However, students from previously disadvantaged backgrounds fared marginally worse than those on the paper-based course. These results allow extrapolation to a broader context where Web-based teaching of disadvantaged communities may be used.
Contact person: Mr BA Carr.
Epidemiology of Early Blight on Potatoes in South Africa. Early blight is a major foliar disease of potatoes in most potato growing regions of the world. Numerous forecasting models have been developed and evaluated for this disease. However, prior to the development of the PLANT-Plus early blight forecaster, none were applicable to South Africa. An early blight decision support system (DSS) was developed in the PLANT-Plus framework for the control of the disease in South Africa. Field trial evaluation of the model and comparison to conventional spray programmes for control of early blight showed that use of the PLANT-Plus model reduced the number of fungicide applications without negatively affecting disease severity or yield. The relationship of weather variables to concentration of airborne conidia of A. solani above a potato crop was investigated to confirm the accuracy of the spore production and dispersal prediction model in the PLANT-Plus DSS. A survey on the current situation of early blight on potatoes, control practices and grower perceptions about the disease was conducted in South Africa using an informally structured questionnaire. Most respondents agreed that early blight is an important disease in South Africa, causing up to 70% yield losses if not controlled, and that research is needed on the disease. This study should find disease management practices that will approach the social optimum, considering farmer income and needs.
Epidemiologie van Vroeëroes op aartappels in Suid-Afrika. Vroeëroes, 'n blaarsiekte van aartappels, is 'n groot probleem in die meeste aartappelprodukserende lande wêreldwyd. Verskeie voorspellingsmodelle is al ontwikkel en geëvalueer vir die beheer van hierdie siekte. Maar, voor die ontwikkeling van die PLANT-Plus voorspellingsmodel was geeneen op Suid-Afrika van toepassing nie. 'n Vroeëroes besluitondersteuningstelsel (BOS) is binne die PLANT-Plus raamwerk ontwikkel vir die beheer van die siekte in Suid-Afrika. Veldproef evaluering van die model en vergelyking met konvensionele spuitprogramme vir die beheer van vroeëroes het bewys dat gebruik van die PLANT-Plus model die hoeveelheid bespuitings verminder sonder om die siekte of opbrengs negatief te beïnvloed. Die Plant-Plus voorspeller hou groot potensiaal vir gebruik in die Suid-Afrikaanse aartappelbedryf in, maar moet met die laatroes voorspeller geïnkorporeer word, om koste-doeltreffend en meerdoelig toegepas te word. Om die akkuraatheid van die spoorproduksie en -voorspellingsverspreidingsmodel in die PLANT-Plus BOS te bevestig, is die verband tussen wisselende weersomstandighede en die konsentrasie luggedraagde konidia van A. solani bokant 'n aartappelland ondersoek. Met behulp van 'n informele vraelys is 'n opname oor die huidige voorkoms van vroeëroes op aartappels, beheerpraktyke en produsentepersepsies oor die siekte in Suid-Afrika gedoen. Die meeste respondente het saamgestem dat vroeëroes 'n groot probleem in Suid-Afrika is wat tot 70% oesverliese kan lei indien dit nie beheer word nie en dat navorsing daarop nodig is. Deur inagneming van boere se inkomste en behoeftes behoort hierdie studie siektebeheerpraktyke naby die sosiale optimum te vind.
Contact person: Ms JE van der Waals (Smith).
|
