Web assisted teaching: an undergraduate experience

The emergence of the Internet has created a number of claims as to the future of education and the possibility of dramatically changing the way in which education is delivered. Much of the attention has focussed on the adoption of teaching methods that are solely web-based. We set out to incorporate web-based teaching as support for more traditional teaching methods to improve the learning outcomes for students. This first step into web-based teaching was developed to harness the benefits of web-based teaching tools without supplanting traditional teaching methods. The aim of this paper is to report our experience with web-assisted teaching in two undergraduate courses, Accounting Information Systems and Management Accounting Services, during 2000. The paper evaluates the approach taken and proposes a tentative framework for developing future web-assisted teaching applications. We believe that web-assisted and web-based teaching are inevitable outcomes of the telecommunications and computer revolution and that academics cannot afford to become isolated from the on-line world. A considered approach is needed to ensure the integration of web-based features into the overall structure of a course. The components of the course material and the learning experiences students are exposed to need to be structured and delivered in a way that ensures they support student learning rather than replacing one form of learning with another. Therefore a careful consideration of the structure, content, level of detail and time of delivery needs to be integrated to create a course structure that provides a range of student learning experiences that are complimentary rather than competing. The feedback was positive from both extramural (distance) and internal students, demonstrating to us that web sites can be used as an effective teaching tool in support of more traditional teaching methods as well as a tool for distance education. The ability to harness the positives of the web in conjunction with more traditional teaching modes is one that should not be overlooked in the move to adopt web based instruction methods. Web-based teaching need not be seen as an all or nothing divide but can be used as a useful way of improving the range and type of learning experiences open to students. The Web challenges traditional methods and thinking but it also provides tools to develop innovative solutions to both distance and on campus learning. Further research is needed to determine how we can best meet the needs of our students while maintaining high quality learning outcomes

Representational layering in Functional Discourse Grammar

The paper addresses the internal structure of layers at the Representational level in Functional Discourse Grammar (FDG), and proposes three adaptations of the representation of frames with respect to what is now standing practice (HENGEVELD; MACKENZIE, 2006; Forthcoming). Our main concern is a reappraisal of Dik’s (1989, 1997) original argumentation for the endocentric use of argument variables within restrictors of terms, which we argue are fundamental to FDG theory and should be generalised over all representational layers. Based on this view, we propose a transparent usage of square brackets, which embrace equipollent configurations of which the argument variable is part. This in turn reveals problems in the representation of the nuclear event description - the verb and its arguments - as an identifiable entity, which is an old problem in FG, as well as in the representation of reference modification. As a unified solution, we invoke exocentric layers to account for the special structural properties of these units. The result is a more consistent and transparent structure of representational frames in FDG

Metabolism of [8-14C] trans-zeatin by intact and decapitated tap roots of Pinus pinea

Intact and root tip-decapitated seedlings of Pinus pinea were treated with [8-14C]zeatin. In intact plants, most of the applied radioactivity remained in the roots. Root tip removal resulted in greater transport of radioactivity to the shoot. The relative distribution of radioactivity along the tap root was non-linear. High amounts of radioactivity associated with zeatin-like compounds were recovered in the elongation zone of intact tap roots. HPLC separation of extracts from the different sections from intact roots showed that the applied zeatin was rapidly metabolized. Very little radioactivity was detected in the upper sections of the root where lateral root formation and lateral root elongation occurred. This radioactivity was not associated with the retention times of authentic cytokinin standards. In the tap root elongation zone, peaks of radioactivity which co-chromatographed with authentic zeatin and iso-pentenyladenine were detected. The uneven distribution of applied cytokinins in the tap root, and particularly the higher levels recovered from the root elongation zone, could explain why lateral roots do not develop in this region

Day clinics and hospitals - a cost comparison

Objective. To determine the types of surgical procedures currently undertaken in day clinics and to compare the number of procedures, the average in-facility cost, and the pre- and post-discharge costs for each procedure or group of procedures.Design. A retrospective descriptive study of medical aid claims data.Setting. Department of Family Medicine, University of the Witwatersrand, Johannesburg.Subject. Three private sector medical aid schemes with in excess of 170 000 principal members (380 000 lives).Outcome measures. For each surgical procedure. the following were compared: (i) the total number of procedures done; (ii) the average total in-facility cost; and (iii) the cost of professional fees and medicines for 7 days before admission, during admission, and for 14 days after discharge.Results. During 1997, 89 216 patients underwent surgery. Day clinics and hospitals accounted for 5 490 and 83 726 admissions respectively. Fifty-one different types of procedures were identified that met the inclusion criteria.On average the in-facility costs for 45 (88%) of the 51 compared procedures were lower in day clinics compared with hospitals. Average costs can be as much as 90% lower in day clinics. Some procedures, particularly certain dental operations, cost more in day clinics. The professional fees of attending doctors and the cost of medicines are generally higher when the procedure is undertaken in a hospital.Conclusion. In South Africa, as is the case in the USA, day clinics have the potential to reduce the cost of surgical procedures

Stress Distribution in Mandible Regulated by Bone and Dental Implant Parameters: Part I - Methodology

The complicated inter-relationships between mandibular bone components and dental implants have attracted the attention of many a structural mechanics researcher as well as many a dental practitioner. This paper describes the methodology and analysis techniques employed to enable accurate evaluation of a vast range of the implant and bone parameters. The complex material and geometric properties of the bone and implant are modelled using two-dimensional (2D) triangular and quadrilateral plane strain elements. Assumptions made in the analysis include: (a) 50% osseointegration between bone and implant; (b) linear relationships exist between the stress value and the Young’s moduli of the cancellous and cortical bone at any specific point. In the companion paper (Part II) various bone, implant and loading parameters are evaluated for their influence on the stress distribution within the bone, in particular in the mandible

Assessments and improvement of filter media cleanliness in rapid gravity sand filters

Introduction: Rapid sand filtration is an essential unit process in the water purification process. It captures and removes coagulated and flocculated material and other suspended matter not removed during the preceding treatment processes. The pores in the filter bed gradually become clogged and the media progressively collects deposit through the continuous use and life of the filter. During normal operations cleaning is initiated by excessive head loss, deterioration in filtrate quality or when the predetermined time for a filter run has elapsed. Air scour, to remove deposit from filter media by vigorous agitation, and wash water, to remove this deposit from the filter bed, are applied. The combined action of air and water should quickly return the media to its original perfectly clean state for the cycle to continue. However, on inspection it is often found that filter sand on purification plants is unacceptably dirty and backwash systems are clearly incapable of cleaning the media to its initial state of cleanliness. It is at times possible to relate the dirty filter media to faulty designs or poor operating procedures, but often the reasons for the media deterioration remain elusive and the media becomes dirtier the longer it is in use. As there was an almost complete lack of published or agreed upon procedures to measure the cleanliness of filter media, rudimentary methods for measuring filter media cleanliness and backwash efficiency were developed. Thereafter filter media from full-scale treatment plants was analyzed with these methods at regular intervals to establish some benchmarks for these determinants. These methods were also applied during the laboratory and pilot plant phases of the project

In vivo study of aerosol droplets and splatter reduction in dentistry

Oral healthcare workers (OHCW) are exposed to pathogenic microorganisms during dental aerosol-generating procedures. Technologies aimed at the reduction of aerosol droplets and splatter are essential. This in vivo study assessed aerosol droplets and splatter contamination in a simulated clinical scenario. The coolant of the high-speed air turbine was colored with red concentrate. The red aerosol droplets and splatter contamination on the wrists of the OHCW and chests of the OHCW/volunteer protective gowns were assessed and quantified in cm2. The efficacy of various evacuation strategies were assessed: low-volume saliva ejector (LV) alone, high-volume evacuator (HV) plus LV, and an extra-oral dental aerosol suction device (DASD) plus LV. The Kruskal– Wallis rank-sum test for multiple independent samples with a posthoc test was used. No significant difference between the LV alone compared to the HV plus LV was demonstrated (p = 0.372059). The DASD combined with LV resulted in a 62% reduction of contamination of the OHCW. The HV plus LV reduced contamination by 53% compared to LV alone (p = 0.019945). The DASD demonstrated a 50% reduction in the contamination of the OHCWs wrists and a 30% reduction in chest contamination compared to HV plus LV. The DASD in conjunction with LV was more effective in reducing aerosol droplets and splatter than HV plus LV. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Fifty years of maintenance optimization: Reflections and perspectives

peer reviewe

Low levels of physical activity in female adolescents cause overweight and obesity: Are our schools failing our children?

The increasing prevalence of overweight and obesity among female adolescents is a global health problem. In developing countries such as South Africa, this increase is often associated with urbanisation and the adoption of a Western lifestyle. Two aspects of the Western lifestyle that contribute to the development of overweight and obesity are a decrease in physical activity levels and an increase in the consumption of energy-dense food, high in fats and refined sugar. Information on the prevalence of increased body fatness in populations in transition is scarce, but necessary for effective planning and intervention. Current indications are that there is a trend towards unhealthy behaviour among high-school girls, globally and in South Africa. Schools can play an important role in the prevention of overweight and obesity among schoolgirls. It is recommended that school governing bodies institute remedial action to prevent weight gain in children, especially girls