Thesis (MSportwet)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The purpose of this study was to investigate the influence of a six-week plyometric training programme on the explosive power, speed and agility as well as certain physiological characteristics and the physical fitness of rugby players. Thirty subjects, that include the first and second rugby teams of the Paul Roos Gymnasium participated in the study. After a thorough evaluation of their medical history, their health status was confirmed as being “apparently healthy” and fit for participation in the project. The subjects were divided into two groups. The experimental group followed a specially designed plyometric training programme in addition to their conventional rugby training, while the control group persisted with the conventional rugby training for the season. Body fat percentage was measured and specific girth measurements were taken to assess physiological changes. Cardiovascular fitness was evaluated by means of the threeminute step test and muscle endurance by means of the push-up and sit-up tests in order to assess the physical fitness of the subjects. The explosive power, speed and agility of the subjects were assessed by means of the agility test [T-drill], ten-meter speed test, Sargent vertical jump test, depth jump test, standing triple jump and the medicine ball chest pass. All measurements and tests were taken before and after the six-week intervention programme of plyometric training. With regards to physiological changes the results showed that the plyometric training programme had a positive effect on the experimental group. The body fat percentage of the experimental group showed a significant decrease and the circumference of their thighs, calves, arms and waist increased. Their chest circumferences did, however, not increase, which might be due to the fact that the plyometric exercises were more specifically aimed at the lower body muscle groups. The results pertaining to physical fitness were mixed. There was a significant improvement (p<0,01) in the cardiovascular fitness of the experimental group while that of the control group stayed relatively constant (p=1,0). With regards to muscle endurance, the control group fared significantly better in the push-up test than the experimental group, while the experimental group fared significantly better in the sit-up test than the control group. The six-week plyometric intervention programme had a statistically significant effect on the performance of the experimental group as compared to the control group, when biomotor skills were assessed. It was concluded that the addition of the specific plyometric exercises to a conventional rugby-training programme would improve the speed, explosive power and agility of rugby players significantly. Beneficial anthropometric changes as well as improved cardiovascular fitness would be additional benefits of a plyometric training programme. The findings of this research suggest that the value of plyometric exercises to motor skills, specific physiological characteristics and physical fitness should not be underestimated and that the trainers and coaches should be informed in this regard. To establish the positive effects of plyometrics as a functional cross training regime for rugby players, more comprehensive research is, however, recommended. / AFRIKAANSE OPSOMMING: Die doel van die navorsing was om die effek van ‘n ses-weeklange pliometriese oefenprogram op die eksplosiewe krag, spoed, ratsheid asook sekere fisiologiese karaktereienskappe en die fisieke fiksheid van rugbyspelers te ondersoek. Dertig spelers, wat lede van die eerste en tweede rugbyspan van Paul Roos Gimnasium hoërskool ingesluit het, het aan die studie deelgeneem. Na deeglike evaluering van hulle mediese geskiedenis, is hulle gesondheidsvlakke goedgekeur vir deelname in die studie. Die spelers is in twee groepe verdeel. Die eksperimentele groep het ‘n spesiale pliometriese oefenprogram gevolg, saam met die konvensionele rugby-oefensessies. Die kontrole groep het slegs aan die konvensionele rugby-oefensessies vir die seisoen deelgeneem. Persentasie liggaamsvet en spesifieke omtrekmates is genoteer om die fisiologiese veranderinge te evalueer. Kardiovaskulêre fiksheid is deur middel van ‘n drie-minute opstaptoets geëvalueer en spieruithouvermoë deur middel van opstoot-en opsittoetse om sodoende die speler se fisieke fiksheid te evalueer. Die ratsheid, spoed en eksplosiewe krag van die spelers is deur die ratsheidstoets (T-drill), tien-meter spoedtoets, Sargent vertikale sprongtoets, diepte sprongtoets, staande driesprong en die medisynebal-gooitoets bepaal. Al die bogenoemde toetse en assessering is voor en na die ses-weke intervensie program van pliometriese oefening gedoen. Met betrekking tot die fisiologiese veranderinge, dui die resultate aan dat die pliometriese oefenprogram ‘n positiewe effek op die eksperimentele groep gehad het. Die eksperimentele groep se persentasie liggaamsvet het beduidend verlaag en daar was ‘n neiging tot toename in omtrekmates van die bobeen, kuite, arms en middel. Die borsomtrekmate het egter nie vergroot nie, en kan toegeskryf word aan die feit dat die pliometriese oefenprogram op die ontwikkeling van die spiere in die onderlyf gefokus het. Die resultate ten opsigte van die fisieke fiksheid was eenders vir die twee groepe. Daar was ‘n neiging tot verbetering in die kardiovaskulêre fiksheid van die eksperimentele groep, terwyl die kontrole groep konstant gebly het. Met betrekking tot spieruithouvermoë het die kontrole groep in die opstoottoets verbeter in vergelyking met die eksperimentele groep. Die eksperimentele groep het egter weer verbeter (p<0,01) in die opsittoets, terwyl die kontrole groep konstant (p=1,0) gebly het. Die eksperimentele groep het statisties betekenisvol in die biomotoriese vaardigheidtoetse verbeter na die ses-weeklange pliometriese oefenprogram. Die kontrole groep het geen verbetering getoon nie. Die gevolgtrekking is dat ‘n kombinasie van ‘n pliometriese oefenprogram en konvensionele rugby-oefening kan lei tot die verbetering van spoed, eksplosiewe krag en ratsheid van spelers. Positiewe antropometriese veranderinge sal addisionele voordele van die pliometriese oefenprogram wees. Die bevinding van die navorsing is dat die waarde van pliometriese oefening vir biomotoriese vaardighede, spesifieke fisiologiese eienskappe en fisieke fiksheid nie onderskat moet word nie en dat afrigters in hierdie opsig ingelig word. Om die positiewe effek van pliometrie as ‘n funksionele alternatiewe oefenmetode vir rugbyspelers te bewys, word meer intense navorsing oor die effek van die spesifieke oefenmetode aanbeveel.

Thesis (MPhil)--University of Stellenbosch,2002. / ENGLISH ABSTRACT: Changing circumstances and new initiatives have made it necessary for Higher Education institutions to reflect on all aspects of their teaching portfolios. Recent global and national trends have had numerous implications for different aspects of the university as an entity, which in turn have important implications for teaching, and particularly postgraduate teaching. The need for greater transparency and efficiency is forcing universities into discussions around facing these challenges. The overarching aims of this study were twofold: firstly, to identify historical and current tendencies and patterns in postgraduate studies at the University of Stellenbosch and secondly, to determine the enabling and constraining factors relating to postgraduate studies at the University of Stellenbosch. It was decided to focus on both completed postgraduate students (years 1991 - 1999) as well as current postgraduate students (year 2000). Furthermore, "postgraduate" was defined as relating to all Master's and Doctoral students at the University of Stellenbosch. The empirical research for this study included three components. Firstly, two postal surveys were carried out at the University of Stellenbosch in 2000 in order to explore a representative sample of postgraduate students' attitudes and perceptions. Secondly, a secondary data analysis of existing data on the University database for postgraduate students was carried out in order to do an estimate of success- and follow through rates. Finally, interviews were conducted with coordinators of four postgraduate programmes at different departments in the Faculty of Arts at the University of Stellenbosch. Results show that the nature of postgraduate studies at the University follows the same form of dynamics, diversity and complexity that characterizes postgraduate studies worldwide. Although there has been an exceptional increase in the number of postgraduate students over the past decade, completion rates have stayed the same. This increase in numbers places enormous additional administrative, academic and managerial demands on the University. Although postgraduate students (both completed and current students) seem to have a general positive perception of the University, its academic and administrative services as well as the quality of postgraduate supervision, there are certain aspects that can still be improved upon. For example: the University has to realize that although the completion rates of postgraduate students have reasonably stayed the same over the last decade, the number of students who did not complete increased with almost 50%. The University has to put structures in place in order to cope with the increasing demands these students are placing on administration, departments and supervisors. Also, although it seems as if the University are open to the trends in higher education, they are not totally geared for part-time and non-resldentlal students. All four programmes in the Arts Faculty were initiated by individual academics within the departments. In terms of managing postgraduate students within departments, it seems that greater standardization regarding aspects of admission, administrative support, requirements for research proposals, examination and guidelines for the research components are needed. Supervisors and students both need to know what is expected from them. In terms of the supervisory process, supervisors must have guidelines in terms of what their responsibilities are and they have to realize the importance of their task. Students need to be informed about their rights and the whole process of postgraduate studies. Overall, it is the responsibility of the University, together with its postgraduate students and supervisors to ensure that the process of postgraduate studies is characterized by success, effectiveness and efficiency. / AFRIKAANSE OPSOMMING: Veranderende omstandighede en nuwe beleldsmaatreels maak dit noodsaaklik dat Hoer Onderwysinrigtings deurentyd besin oor aile aspekte van hul missies en funksies. Resente globale en nasionale tendense het verreikende implikasies vir verskeie aspekte van die universiteitswese, waarvan die gevolge vir die onderrigtaak, en in besonder nagraadse onderrig, van besondere belang is. Oproepe tot deursigtigheid, gekoppel aan die imperatief tot doeltreffendheid, is alles faktore wat universiteite tot besinning dwing. Die doel van hierdie studie was om die historiese en huidige tendense en patrone in nagraadse studie aan die Universiteit van Stellenbosch te skets asook om vas te stel wat is die bemiddelende en belemmerende faktore wat nagraadse studie by die Universiteit kenmerk. Daar is besluit om te fokus op beide afgestudeerde studente (vanaf 1991 tot 1999) asook huidige studente (ingeskryf in die jaar 2000). Verder is "nagraads" gedefinieer as verwysende na aile meesters en doktorale studente by die Universiteit van Stellenbosch. Die empiriese navorsing vir hierdie studie bestaan uit drie komponente. Eerstens is twee posopnames in 2000 uitgevoer om "n verteenwoordigende steekproef van nagraadse studente aan die Universiteit se persepsies rakende hul nagraadse studie te toets. Verder is daar "n sekondere analise uitgevoer van bestaande data op die Universiteit se databasis vir nagraadse studente spesifiek met die doel om sukses- en deurvloeikoerse van nagraadse studente te bepaal. Laastens is onderhoude gevoer met koordineerders van vier nagraadse programme aan verskillende departemente binne die Fakulteit Lettere en Wysbegeerte. Die resultate toon dat die aard van nagraadse studie aan die Universiteit van Stellenbosch dieselfde mate van dinamika, toenemende diversiteit en gepaardgaande kompleksiteit weerspleel as wat nagraadse studies wereldwyd kenmerk. Alhoewel daar "n buitengewone toename in nagraadse studentegetalle aan die Universiteit oor die afgelope dekade was, het die voltooiingskoerse van studente dieselfde gebly. Hierdie toename in getalle plaas geweldige ekstra administratiewe, akademiese en bedryfseise aan die Universiteit. Alhoewel nagraadse studente (beide afgestudeerd sowel as huidig) in die algemeen "n positiewe persepsie van die Universiteit, sy akadernlese en administratiewe dienste, sowel as die kwaliteit van nagraadse studieleiding blyk te he, is daar enkele sake waarop verbeter kan word. 50 byvoorbeeld moet die Universiteit besef dat alhoewel voltooiingskoerse konstant gebly het, het die getal van nagraadse studente wat nie voltooi nie, met ongeveer 50% gestyg. Die Universiteit moet strukture in plek stel om te kan voldoen aan die toenemende eise wat sy nagraadse studente aan administrasie, departemente en studieleiers stel. Alhoewel die Universiteit oop blyk te wees vir nuwe tendense in hoer onderwys, blyk dit dat hy nog nie heeltemal gerat is vir deeltydse studente en nle-resldenslele studente nie. AI vier die programme in die Fakulteit Lettere en Wysbegeerte het ontwikkel uit individuele akademici binne departemente. In terme van die bestuur van nagraadse studente binne departemente, is groter standardisasie van aspekte rakende toelating, administratiewe ondersteuning, vereistes rondom navorsingsvoorstelle, eksaminering en riglyne vir die navorsingskomponent van nagraadse studies nodig. Beide studieleiers en studente moet besef wat van hulle verwag word. In terme van die proses van studieleiding, moet studieleiers oor riglyne beskik van hulle verantwoordelikhede en verder moet die belangrikheid van die taak besef word. 5tudente moet ingelig word oor hulle regte en die proses van nagraadse studie. Die Universiteit, tesame met sy nagraadse studente en studieleiers, moet verseker dat die proses van nagraadse studies gekenmerk word deur sukses, effektiwiteit en doeltreffendheid.

Thesis (MBA)--University of Stellenbosch, 2010. / Popularity of social media sites is growing at a fast rate and many businesses and higher education institutions are attempting to successfully engage with their stakeholders using this new interactive medium that facilitates ‘many-to-many’ communication. There are several forms of social media and users have many options available to them, ranging from the more generic social networking sites, like Facebook, to more niche sites, like BlackPlanet that targets black African Americans. The focus of this research is on the social media usage patterns and trends in the stakeholder groups of the University of Stellenbosch Business School (USB). Eight stakeholder groups were identified and they consist of the following groups and USB departments: i) USB prospective students; ii) USB current students, busy with their research reports; iii) USB current students, not busy with their research reports; iv) USB alumni; v) USB course administrators; vi) USB academic faculty members; vii) USB research supervisors; viii) USB Marketing and Communication Division. The analysis showed that the social media site Facebook is popular among all stakeholder groups of the USB, followed by LinkedIn and YouTube. Furthermore, Facebook and LinkedIn were cited as the preferred social media sites for the USB to use in communicating with its stakeholder groups. Additionally, respondents indicated strong privacy concerns with the use of social media. Numerous other similarities and differences by gender, age group and stakeholder groups were discussed in the findings. Combined with information from literature, these findings were translated into a multistep plan to improve the communication among the USB’s stakeholder groups. The fast-changing social media landscape requires businesses and higher education institutions, like the USB, to stay abreast of the latest user trends to ensure continued interaction with their stakeholders. Therefore, regular investigations by the USB into the use of social media by its stakeholder groups are required in the foreseeable future.

Thesis (MBA)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Managing any government institution has become increasingly complicated as the requirements for accountability, streamlined operations and greater flexibility have multiplied. Being a government institution but at the same time an institution of higher education, managing the Faculty of Military Science becomes a daunting task. It requires sophisticated approaches for implementing strategy and measuring performance. Employees are asked to change how they view their work and focus on results, not activities. While not asking the impossible, it is a challenging task. Formal accountability for outcomes down the line has simply not been a marker of the bureaucratic culture. As leadership looks for ways to support employees in this transition, it is vital that a comprehensive management system is deployed. For employees to focus on the outcomes of their individual performance, they must: • understand what the standards for organisational performance are; • participate in measuring how well those standards have been met; and • be responsible for finding ways to improve organisational performance. The Balanced Scorecard can help. This approach is one that is gaining currency as an easy to use and accessible process for measuring organisational effectiveness. It can be applied at any level and any type of organisation. The objectives and measures for the Balanced Scorecard are derived from the organisation's vision and strategy. These objectives and measures describe the progress of the organisation from four perspectives. These perspectives can vary from organisation to organisation and in the case of the Faculty of Military Science they include, the stakeholder perspective, the customer perspective, the internal processes perspective and the learning and growth perspective. It is a balanced model, because the measures represent an equilibrium between external measures for stakeholders and customers, and internal measures of business processes and learning and growth. The construction of the Balanced Scorecard is a systematic process, which ensures that the organisation's objectives and measures are made clear and that there is consensus in this regard. The success of the process depends on the participation of top management. The most important person in the process is the leader or "architect. A Balanced Scorecard can be constructed in 16 weeks, with high involvement of the leader in the beginning of the process. The Balanced Scorecard must be used as a strategic management system. It helps to clarify and to gain consensus about vision and strategy of the organisation, which should be communicated throughout the organisation. It is also useful in the establishment of objectives for each employee, the allocation of resources and the alignment of strategic initiatives, This study is directed towards the relevant literature on the Balanced Scorecard and the possible use thereof as a management system in an institution for higher education, specifically the Faculty of Military Science. To this end a thorough literature study was undertaken, focusing on the origins of the Balanced Scorecard, the developing and implementation thereof as well as the Balanced Scorecard as a strategic management system. The study further determined the applicability of the Balanced Scorecard to institutions for higher education, looking at the University of California, San Diego, as an example. In the final instance a Balanced Scorecard is proposed for the Faculty of Military Science, with certain recommendations. / AFRIKAANSE OPSOMMING: Toenemende druk op staatsinstellings om meer aanspreeklikheid te aanvaar, aktiwiteite meer vaartbelyn uit te voer en om meer buigsaam in hul optrede te wees, veroorsaak dat die bestuur van sulke instellings toenemend kompleks begin word. Die bestuur van die Fakulteit Krygskunde, 'n staatsinstelling, maar ook 'n instelling vir hoër onderwys, bied dus 'n geweldige uitdaging. Dit vereis daarom 'n gesofistikeerde benadering tot die implementering van 'n strategie en die meet van prestasie. Van werknemers word verwag om hul siening van werk te verander deur te fokus op resultate eerder as op aktiwiteite - 'n uitdaging op sy eie. Aanspreeklikheid vir die bereiking van resultate op lae vlakke in 'n staatsinstelling was nog nooit deel van 'n burokratiese kultuur nie. Vir leierskap om werknemers met hierdie aanpassing te ondersteun, is 'n omvattende bestuurstelsel nodig. Vir werknemers om te fokus op die uitkomste van hul individuele prestasies, moet hulle: • die prestasiestandaarde van die organisasie verstaan; • deelneem om te bepaal tot watter mate die standaarde bereik is; en • verantwoordelikheid neem om te bepaal hoe die prestasie van die organisasie verbeter kan word. Dit wat 'n organisasie meet en hoe die resultate daarvan gekommunikeer word lewer 'n sleutel bydrae t.o.v die voortdurende verbetering van prestasie deur die werknemers. Die "Balanced Scorecard" kan op hierdie gebied 'n groot bydrae lewer. Dit is 'n benadering wat wye veld wen as 'n eenvoudige en toeganklike proses om die effektiewiteit van 'n organisasie te meet. Die benadering kan op enige vlak en enige tipe organisasie toegepas word. Die doelwitte en maatstawwe vir die "Balanced Scorecard" word direk afgelei uit die organisasie se visie en strategie. Hierdie doelwitte en maatstawwe beskryf die organisasie se vordering uit vier perspektiewe. Hierdie perspektiewe kan wissel van organisasie tot organisasie en in die geval van die Fakutteit Krygskunde sluit dit in, die belanghebber perspektief, die kliente perspektief, die interne prosesse perspektief en die leer- en groeiperspektief. Die model word as gebalanseerd beskou omdat dit 'n ewewig tussen die eksterne maatstawwe (vir aandeelhouers, belanghebbers en kliente) en interne maatstawwe (besigheidsporosesse en leer- en groeifasette) handhaaf. Die bou van 'n "Balanced Scorecard" is 'n sistematiese proses, wat konsensus en duidelikheid met betrekking tot die organisasie se doelwitte en maatstawwe verseker. Die sukses van die hele proses berus egter op die ondersteuning en deelname van die topbestuur. Die belangrikste persoon in die hele proses is die leier of "argitek". 'n "Balanced Scorecard" kan binne 16 weke voltooi word, met die leier se betrokkenheid baie hoog aan die begin van die hele proses. Die "Balanced Scorecard" moet as 'n strategiese bestuurstelsel gebruik word. Dit kan help om die visie en strategie duidelik te stel en om konsensus daaroor te bereik. Dit moet aan die hele organisasie gekommunikeer word. Dit is verder nuttig in die opstel van doelwitte vir elke werknemer, die allokasie van hulpbronne en die rig van strategiese inisiatiewe. Hierdie studie is gerig tot die relevante literatuur t.o.v die "Balanced Scorecard" en die potensiele gebruik daarvan as 'n bestuurstelsel by 'n instelling van hoër onderwys, en spesifiek die Fakulteit Krygskunde. 'n Deeglike literatuurstudie is gedoen oor die oorsprong van die "Balanced Scorecard", die ontwikkeling en implementering daarvan, asook die aanwending van die "Balanced Scorecard" as 'n strategiese bestuurstelsel. Die studie het ook die toepaslikheid van die "Balanced Scorecard" ondersoek deur te verwys na die Universiteit van Kalifornie, San Diego as 'n voorbeeld. In die finale instansie word 'n "Balanced Scorecard" voorgestel vir die Fakulteit Krygskunde met sekere aanbevelings.

Thesis (MBA)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: This work provides a comprehensive overview of the theories on adult learning. For each approach, the applicability for a leadership development programme is discussed. If available, examples for the use of a certain theory in a leadership course as part of a Master of Business Administration (MBA) programme are provided. An overview of the Personal Leadership Development Journey (PLDJ) of the University of Stellenbosch Business School (USB) is provided. The structure of the programme demonstrates the application of certain adult learning theories. Interviews with the alumni of the programme show how successfully the adult learning theories are practised and to what extent students have found them useful. Gaps in these interviews are pointed out with reference to the theories on adult learning. As an example, there is a certain body of literature on transformative learning as a subcategory of adult learning. In this case, two different theoretical approaches are explained, of which one is a more general discussion on adult learning and the other is focused on leadership development. Then an example of the application of this theory at the Institut Européen des d’Administration d’Affaires (INSEAD) shows how other business schools employ the theory in practice. In this case, the practical example is a leadership course as such, not a general MBA programme. The reason for this is that examples which match the situation at the USB exactly can not always be found. In the interviews, alumni of the USB were asked how the PLDJ impacted their professional and their private life. So indirectly, students were asked if a transformative learning process had taken place and how they would describe it. The analysis of the results is used to point out the strength of the programme as well as gaps, which could be addressed for future improvement.

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Malaria infects over 200 million individuals and leads to the death of over 600 000 people annually. Currently artemisinin combination therapy treatments are effective in treating the disease, but resistance has started to emerge in Cambodia and it is suspected in parts of Vietnam. To maintain the drive to eradicate malaria globally, a great deal of research is aimed at identifying novel prevention strategies, vaccines and antimalarial compounds. Plasmodium falciparum, the most deadly of the malaria parasites, is entirely dependent on glycolysis for ATP. Several of the enzymes within this pathway have been proposed as drug targets and studied in isolation, but the pathway as a whole has not been considered. In this study we employ a bottom up approach for drug target identification in P. falciparum glycolysis. In this thesis we present the biochemical characterisation each of the glycolytic enzymes in P. falciparum trophozoites. The kinetic rate equations, which described the kinetic behaviour of the individual enzymes, were incorporated into a kinetic model. The unfitted model was validated in its ability to predict experimentally measured steady state metabolite concentrations and fluxes as well as the experimental inhibition of the glucose transporter. The validated model provided a tool for drug target identification in P. falciparum glycolysis. Metabolic control analysis and differential control analysis identified the glucose transporter, PfHT1, as a drug target based on its high control of glycolytic flux in the parasite, but low control of flux in the host erythrocyte. This differential control makes the transporter an attractive drug target, as even if both the erythrocyte and parasite glucose transporters are inhibited to the same degree, it is expected that the parasite glycolytic flux would be inhibited to a much greater degree. To demonstrate the differential control of the glucose transporter on the flux and provide further evidence that PfHT1 is an attractive drug target, we investigated the inhibition of the glucose transporter in isolated trophozoites by cytochalasin B. We also measured the inhibition of lactate production flux by cytochalasin B in both isolated P. falciparum trophozoites as well as in erythrocytes. Our findings demonstrated that differential control analysis can be used as a tool for drug target identification and that PfHT1 is an attractive drug target. In this study the fields of biochemistry and systems biology were merged to create a detailed kinetic model of asexual P. falciparum glycolysis and identify several drug targets in the pathway. The model prediction and experimental evidence of differential flux control of the glucose transporter in the host and parasite, has highlighted PfHT1 as a drug target and also demonstrates the strength of differential control analysis in identifying drug targets within a system. The kinetic model is a valuable tool for furthering our understanding of P. falciparum glycolysis and it provides a good foundation for expansion to identify drug targets in the entire central carbon metabolism of P. falciparum. / AFRIKAANSE OPSOMMING: Malaria infekteer meer as 200 miljoen mense en veroorsaak jaarliks tot 600 000 sterftes. Tans is die artemisinien-kombinasieterapie effektief in die bestryding van die siekte, maar weerstandbiedendheid van die parasiet teen die middel blyk reeds ’n merkbare effek in Kambodja en vermoedelik ook in dele van Viëtnam te hê. Om ’n wêreldwye bestryding van malaria moontlik te maak, is ’n groot deel van die huidige navorsing gemik op die identifisering van nuwe voorkomingsstrategieë, entstowwe en malariateenmiddels. Plasmodium falciparum, die dodelikste van die malaria-parasiete, is geheel en al afhanklik van glikolise vir ATP vorming. Verskeie van die ensieme in hierdie metaboliese pad is as teenmiddelteikens voorgestel, en in isolasie bestudeer, maar die pad as ’n geheel is nie bestudeer nie. In hierdie studie het ons ’n ’bottom-up’ benadering vir teenmiddel teikenidentifisering in P. falciparum glikolise gebruik. In hierdie tesis bied ons die biochemiese karakterisering van elk van die glikolitiese ensieme in P. falciparum trofozoïete aan. Die kinetiese vergelykings wat die kinetiese gedrag van die individuele ensieme beskryf, is geintegreer in ’n enkele kinetiese model. Die model waarop geen datapassing toegepas is nie, is gevalideer om eksperimenteel bepaalde bestendige-toestand metabolietkonsentrasies en fluksiewaardes, asook die eksperimentele inhibisie van die glukose transporter, te voorspel. Die gevalideerde model verskaf ’n bykomende hulpmiddel om teenmiddelteikens te identifiseer in P. falciparum glikolise. Metaboliese kontrole-analise en differensiële kontrole-analise het die glukose transporter, PfHT1, as ’n teenmiddelteiken geïdentifiseer, gebaseer op sy hoë kontrole van glikolitiese fluksie in die parasiet, tesame met ’n lae beheer van die glukose transporter op die fluksie in die gasheer eritrosiet. Dié differensiële kontrole maak die glukose transporter ’n aantreklike teenmiddelteiken, want selfs as beide die eritrosiet en die parasiet glukose transporters tot dieselfde mate geïnhibeer word, sal dit steeds ’n hoër glikolietiese fluksieinhibisie van die parasiet tot gevolg hê. Om die differensiële kontrole van die glukose transporter op die fluks te demonstreer en verdere bewyse te lewer dat PfHT1 ’n teenmiddelteiken kan wees, het ons die inhibisie van die glukosetransporter in geïsoleerde trofozoïete deur sitokalasien B ondersoek. Ons het ook die inhibisie van die laktaatproduksiefluksie deur sitokalasien B in beide geïsoleerde P. falciparum trofozoïete sowel as in eritrosiete ondersoek. Ons bevindings bewys dat differensiële kontroleanalise as ’n hulpmiddel vir teenmiddelteikenidentifikasie gebruik kan word en dat PfHT1 ’n aantreklike teenmiddelteiken is. In hierdie studie is die velde van biochemie en sisteembiologie gekombineer om ’n gedetaileerde kinetiese model van ongeslagtelike P. falciparum glikolise te konstueer en verskeie teenmiddelteikens in die metaboliese pad te identifiseer. Die modelvoorspelling sowel as eksperimentele bewyse van die differensiële flukskontrole van die glukose transporter in die gasheer en parasiet het PfHT1 uitgelig as ’n teenmiddelteiken en demonstreer ook die krag van differensiële kontrole analise in die identifisering van teenmiddelteikens binne ’n biologiese stelsel. Die kinetiese model is ’n waardevolle hulpmiddel vir die bevordering van ons begrip van P. falciparum glikolise en dit bied ’n goeie basis vir uitbreiding om teenmiddelteikens in die hele sentrale koolstofmetabolisme van P. falciparum te identifiseer.

Thesis (MScEng)--Stellenbosch University, 2006. / ENGLISH ABSTRACT: The Stellenbosch University Compressor Code (SUCC) has been developed for the purpose of predicting the performance of axial flow compressors by means of axisymmetric inviscid throughflow methods with boundary layer blockage and empirical blade row loss models. This thesis describes the process of the implementation and verification of a number of stall prediction criteria in the SUCC. In addition, it was considered desirable to determine how certain factors influence the accuracy of the stall prediction criteria, namely the nature of the computational grid, the choice of throughflow method used, and the use of a boundary layer blockage model and a radial mixing model. The stall prediction criteria implemented were the di®usion factor limit criterion, de Haller's criterion, Aungier's blade row criterion, Aungier's boundary layer separation criterion, Dunham's, Aungier's and the static-to-static stability criteria. The compressors used as test cases were the Rofanco 3-stage low speed compressor, the NACA 10-stage subsonic compressor, and the NACA 5-stage and 8-stage transonic compressors. Accurate boundary layer blockage modelling was found to be of great importance in the prediction of the onset of stall, and that the matrix throughflow Method provided slightly better accuracy than the streamline curvature method as implemented in the SUCC by the author. The ideal computational grid was found to have many streamlines and a small number of quasi-orthogonals which do not occur inside blade rows. Radial mixing modelling improved the stability of both the matrix throughflow and streamline curvature methods without significantly affecting the accuracy of the stall prediction criteria. De Haller's criterion was over-conservative in estimating the stall line for transonic conditions, but more useful in subsonic conditions. Aungier's blade row criterion provided accurate results on all but the Rofanco compressor. The diffusion factor criterion provided over- optimistic predictions on all machines, but was less inaccurate than de Haller's criterion on the NACA 5-stage transsonic machine near design conditions. The stability methods performed uniformly and equally badly, supporting the claims of other researchers that they are of limited usefulness with throughflow simulations. Aungier's boundary layer separation method failed to predict stall entirely, although this could reflect a shortcoming of the boundary layer blockage model. / AFRIKAANSE OPSOMMING: Die Stellenbosch University Compressor Code (SUCC) is ontwikkel om die prestasie van aksiaalvloei kompressors te voorspel met behulp van aksisimmetriese nie-viskeuse deurvloeimetodes met grenslaagblokkasie en empiriese modelle vir die verliese binne lemrye. Hierdie tesis beskryf die proses waarmee sekere staakvoorspellingsmetodes in die SUCC geïmplementeer en geverifieer is. Dit was ook nodig om die effek van sekere faktore, naamlik die vorm van die berekeningsrooster, die keuse van deurvloeimetode en die gebruik van `n grenslaagblokkasiemodel en radiale vloeivermengingsmodel op die akuraatheid van die staakvoorspellingsmetodes te bepaal. Die staakvoorspellingsmetodes wat geïmplementeer is, is die diffusie faktor beperking metode, de Haller se metode, Aungier se lemrymetode, Aungier se grenslaagmetode en die Dunham, Aungier en die statiese-tot-statiese stabiliteitsmetodes. Die kompressors wat gebruik is om die metodes te toets is die Rofanco 3-stadium lae-spoed kompressor, die NACA 10-stadium subsoniese kompressor en die NACA 5- en 8-stadium transsoniese kompressors. Daar is vasgestel dat akkurate grenslaagblokkasie modelle van groot belang was om `n akkurate aanduiding van die begin van staking te voorspel, en dat, vir die SUCC, die Matriks Deurvloei Metode oor die algemeen 'n bietjie meer akkuraat as die Stroomlyn Kromming Metode is. Daar is ook vasgestel dat die beste berekeningsrooster een is wat baie stroomlyne, en die kleinste moontlike getal quasi-ortogonale het, wat nie binne lemrye geplaas mag word nie. Die numeriese stabiliteit van beide die Matriks Deurvloei en die Stroomlyn Kromming Metode verbeter deur gebruik te maak van radiale vloeivermengingsmodelle, sonder om die akkuraatheid van voorspellings te benadeel. De Haller se metode was oorkonserwatief waar dit gebruik is om die staak-lyn vir transsoniese vloei toestande, maar meer nuttig in die subsoniese vloei gebied. Aungier se lemrymetode het akkurate resultate gelewer vir alle kompressors getoets, behalwe die Rofanco. Die diffusie faktor metode was oor die algemeen minder akuraat as Aungier se metode, maar meer akkuraat as de Haller se metode vir transsoniese toestande. Die stabiliteitsmetodes het almal ewe swak gevaar. Dit stem ooreen met die bevindings van vorige navorsing, wat bewys het dat hierdie metodes nie toepaslik is vir simulasies wat deurvloeimetodes gebruik nie. Aungier se grenslaagmetode het ook baie swak gevaar. Waarskynlik is dit as gevolg van tekortkomings in die grenslaagblokkasiemodel.

Proefskrif (D. Phil.)--Universiteit van Stellenbosch, 1994. / Bibliografie. Also available via the Internet.

<p>The study seeks to establish the state of infrastructure management system, pertaining to electricity distribution, as an example of policy implementation.</p>

<p>The study seeks to establish the state of infrastructure management system, pertaining to electricity distribution, as an example of policy implementation.</p>