The use of peer review as an evaluative tool in science

Thesis (MPhil)--Stellenbosch University, 2001.ENGLISH ABSTRACT: Peer review as an institutional mechanism for certifying knowledge and allocating resources dates back as far as 1665. Today it can with confidence be stated that it is one of the most prominent evaluative tools used in science to determine the quality of research across all scientific fields. Given the transformation within the processes of knowledge production, peer review as an institutionalised method of the evaluation of scientific research has not been unaffected. Peer reviewers have to act within a system of relevant science and find themselves responsible to the scientific community as well as to public decision-makers, who in turn are responsible to the public. This dual responsibility of reviewers led to the development of criteria to be used in the evaluation process to enable them to measure scientific excellence as well as the societal relevance of science. In this thesis peer review in science is examined within the context of these transformations. In looking at the conceptual and methodological issues raised by peer review, definitions of peer review, its history and contexts of application are examined followed by a critique on peer review. Peer review in practice is also explored and the evaluation processes of four respective funding agencies are analysed with regards to three aspects intrinsic to the peer review process: the method by which reviewers are selected, the review criteria by which proposals are rated, and the number of review stages within each review process. The thesis concludes with recommendations for possible improvements to the peer review process and recommended alternatives to peer review as an evaluative tool.AFRIKAANSE OPSOMMING: Portuurgroep-evaluering as 'n geïnsitutsionaliseerde meganisme in die sertifisering van kennis en die toewys van hulpbronne dateer terug so ver as 1665. Huidiglik kan dit as een van die mees prominente metingsinstrumente van die kwaliteit van navorsing in alle wetenskaplike velde beskou word. Die transformasies wat plaasgevind het binne die prosesse waar kennis gegenereer word, het ook nie portuurgroep-evaluaring as 'n geïnstitusionaliseerde metode van evaluering ongeraak gelaat nie. Portuurgroep-evalueerders bevind hulself binne 'n sisteem van relevante wetenskap. Binne hierdie sisteem het hulle 'n verantwoordelikheid teenoor die wetenskaplike gemeenskap sowel as die publiekebesluitnemers wat op hul beurt weer verantwoordelik is teenoor die publiek. Hierdie dubbele verantwoordelikheid het tot gevolg die saamstel van kriteria waarvolgens evalueerders wetenskaplike uitmuntendheid sowel as relevansie tot die breër samelewing kan meet. Hierdie tesis ondersoek portuurgroep-evaluering teen die agtergrond van hierdie transformasies. Die konseptueie en metodologiese aspekte van portuurgroepevaluering word ondersoek deur eerstens te kyk na definisies van portuurgroepevaluering, die geskiedenis daarvan en kontekste waarbinne dit gebruik word. Tweedens word gekyk na kritiek gelewer op portuurgroep-evaluering. Portuurgroep evaluering binne die praktyk word ook ondersoek waar vier onderskeie befondsingsagentskappe se evaluerings prosesse geanaliseer word. Hierdie analise word gedoen in terme van drie essensiële aspekte binne portuurgroep- evaluering. Hierdie drie aspekte is as volg: 1) die wyse waarop evalueerders geselekteer word, 2) die evalueringskriteria waarvolgens navorsingsvoorstelle gemeet word en 3) die hoeveelheid evalueringsfases binne die protuurgroep-evaluerings proses. Laastens word aanbevelings ter verbetering van die portuurgroep-evaluerings proses as ook voorstelle tot moontlike alternatiewe tot portuurgroep-evaluering as 'n evaluerings instrument gebied

A self-fulfilling prophecy : investigating the role of normative misperceptions in the student drinking culture at Stellenbosch University

Thesis (MA)--University of Stellenbosch, 2011.ENGLISH ABSTRACT: This thesis explores the existence of misperceptions regarding the peer‐drinking norm among undergraduate students at Stellenbosch University and the role of these misperceptions in explaining students’ drinking behaviour. A more permissive perception of the drinking norm has been associated with heavier alcohol consumption and negative consequences for oneself, others and property. Perceptions of the academic norm and its relation to personal academic and drinking behaviour are also investigated. Furthermore, the study examines the role of perceptions of the drinking norm in personal drinking behaviour in the context of other cognitive factors (perceptions), experiences prior to enrolling at university, as well as socio‐demographic and contextual factors. The theoretical framework used to understand the origin, occurrence and perpetuation of misperceptions regarding the social norm includes Bourdieu’s theory of habitus, social norms theory, social learning theory and attribution theory. Data were collected from 640 students out of a random sample of 3 177 who had been invited to participate in a web‐based survey during September 2009. In addition, 18 personal semi‐structured interviews were conducted with students.   Similar to findings of research in other countries, the results of this research show that students at Stellenbosch University tend to perceive other students’ drinking behaviour (descriptive norm) and approval of drinking behaviour (injunctive norm) as more permissive than their own. The degree of misperception increases as the social distance of reference groups increases and is also significantly related to personal alcohol consumption. There is also evidence of misperceptions regarding the academic norm and its association with personal drinking behaviour and academic behaviour. Multiple regression analysis reveals that the perceived drinking norm of close friends is the best predictor of personal drinking behaviour, followed by personal approval of drinking and drinking behaviour during the last year of high school. The data presented here for Stellenbosch University students extend the evidence that peer drinking norms are misperceived and highlights the importance of a student’s experiences before enrolling at university. Furthermore, it provides evidence that misperceiving the drinking norm is a pervasive problem that may have behavioural consequences. Various American higher education institutions have developed and implemented campaigns aimed at correcting these misperceptions. This has resulted in significant reductions in misperceptions as well as in heavy drinking among students. Students at Stellenbosch University and elsewhere might also benefit from these types of intervention strategies.  AFRIKAANSE OPSOMMING: Hierdie tesis ondersoek die bestaan van wanpersepsies aangaande die portuurgroep‐drinknorm onder voorgraadse studente aan Universiteit Stellenbosch en die rol daarvan in die verduideliking van studente se drinkgedrag. ’n Meer liberale persepsie van die drinknorm hou verband met swaarder alkoholgebruik en meer negatiewe gevolge vir die persoon self, ander en eiendom. Die studie ondersoek ook persepsies van die akademiese norm en die verband daarvan met persoonlike akademiese en drinkgedrag. Verder word die rol van persepsies van die drinknorm in persoonlike alkoholgebruik in die konteks van ander bewussynsfaktore (persepsies), ervarings voor inskrywing by die universiteit, asook sosiaal‐demografiese en kontekstuele faktore ondersoek. Die studie maak gebruik van die teoretiese raamwerke van Bourdieu se habitus, sosiale norm‐teorie, sosiale leer‐teorie en attributasieteorie om die oorsprong, aanwesigheid en voortsetting van wanpersepsies te verstaan. Data is versamel onder 640 studente uit ’n ewekansige steekproef van 3 177 studente wat uitgenooi was om gedurende September 2009 aan ’n webgebaseerde opname deel te neem. Daar is ook 18 in‐diepte semi‐gestruktureerde onderhoude met studente gevoer.   Soortgelyk aan bevindinge van navorsing in ander lande, toon resultate van hierdie navorsing dat studente aan Universiteit Stellenbosch geneig is om ander studente se drinkgedrag (beskrywende norm) en goedkeuring van alkoholverbruik (injunktiewe norm) as meer liberaal as hulle eie waar te neem. Die graad van wanpersepsie neem toe namate die sosiale afstand van verwysingsgroepe toeneem en hou ook betekenisvol verband met persoonlike alkoholgebruik. Daar is ook bewyse van wanpersepsies aangaande die akademiese norm en die verband daarvan met persoonlike drink‐  en akademiese gedrag. Resultate van ’n meervoudige regressie‐ontleding wys dat die waargenome drinknorm van goeie vriende die beste voorspeller van persoonlike drinkgedrag is, gevolg deur persoonlike goedkeuring van alkoholgebruik en drinkgedrag gedurende die laaste jaar van hoërskool. Die data van Stellenbosse studente lewer verder bewys dat portuurgroep‐drinknorme verkeerdelik waargeneem word en beklemtoon die belangrikheid van studente se vorige ervarings. Dit bewys ook dat die verkeerde waarneming van die drinknorm ’n konstante probleem is wat gedragsgevolge kan hê. Verskeie Amerikaanse universiteite het al veldtogte ontwikkel en geïmplementeer gemik op die regstel van dié wanpersepsies, en dit het wanpersepsies en swaar drankgebruik onder studente betekenisvol verminder. Studente aan Universiteit Stellenbosch en elders sal waarskynlik ook by soortgelyke intervensiestrategieë baat vind.jfl2011Imported from http://etd.sun.ac.z

The pro-fibrotic and anti-inflammatory foam cell macrophage paradox

AbstractThe formation of foamy macrophages by sequestering extracellular modified lipids is a key event in atherosclerosis. However, there is controversy about the effects of lipid loading on macrophage phenotype, with in vitro evidence suggesting either pro- or anti-inflammatory consequences. To investigate this in vivo we compared the transcriptomes of foamy and non-foamy macrophages that accumulate in experimental subcutaneous granulomas in fat-fed ApoE null mice or normal chow-fed wild-type mice, respectively. Consistent with previous studies in peritoneal macrophages from LDL receptor null mice (Spann et al., 2012 [1]), we found that anti-inflammatory LXR/RXR pathway genes were over-represented in the foamy macrophages, but there was no change in M1 or M2 phenotypic markers. Quite unexpectedly, however, we found that genes related to the induction of fibrosis had also been up-regulated (Thomas et al., 2015 [2]). The progression of the foamy macrophages along anti-inflammatory and pro-fibrotic pathways was confirmed using immunohistochemistry (described fully in our primary research article (Thomas et al., 2015 [2]). Here we provide additional details on production of the macrophages and their transcriptomic comparison, with the raw and processed microarray data deposited in GEO (accession number GSE70126). Our observations on these cells are indeed paradoxical, because foamy macrophages have long been implicated in promoting inflammation, extracellular matrix degradation and atherosclerotic plaque rupture, which must be provoked by additional local mediators. Our findings probably explain how very early macrophage-rich lesions maintain their structural integrity

Music therapists' experiences of developing clinical musicianship during training

This qualitative research study explored six music therapists’ experiences of developing clinical musicianship skills during the music therapy Masters training program at the University of Pretoria. The study was particularly concerned with the influence of previous music training and experiences on the development of clinical musicianship skills; how the development of clinical musicianship skills influenced participants’ musical identities; and how the development of clinical musicianship skills influenced participants’ experiences and use of music in non-clinical settings. The sample was selected from registered music therapists who completed their training in 2011 and 2013 at the University of Pretoria. Semi-structured interviews were conducted. The interview transcriptions were then analysed by means of thematic analysis. Three themes were drawn from the data: pre-training, training, and post-training. Participants described their definition of clinical musicianship skills as well as what learning clinical musicianship skills entail. Their experiences of developing clinical musicianship included new experiences; valuable experiences; easier learning experiences; uncertainties and incompetence; growth and development; challenges with regard to instrumental skills, improvisation, and working with clients; and means of dealing with challenges. Data analysis revealed aspects of participants’ musical training and experiences prior to the music therapy course that were both helpful and hindering to their development of clinical musicianship. Participants also commented on the contrasts between previous musical training and experiences and their experiences in music therapy training. With regard to the influence that the music therapy training had on participants’ musical identities, changes included: development to identity as musician, music therapy adding to facets of musical identity, and other musical identities being informed by the training. Data analysis further revealed that the development of clinical musicianship skills informed participants’ use and experiences of music in non-clinical settings in that it influenced their relationships in general, changed their perceptions and experiences of music, and influenced their approach towards musicing.Mini-dissertation (Mmus)--University of Pretoria, 2015.tm2015MusicMmusUnrestricte

Internal migration in post-apartheid South Africa: The cases of the Western and Northern Cape

Thesis (PhD)--Stellenbosch University, 2018.ENGLISH ABSTRACT: Internal migration in post-apartheid South Africa is the primary focus of this dissertation. The geographic focus is on two of the country’s current provinces. In both the Northern Cape and the Western Cape provinces, apartheid policies that restricted the free movement of certain South Africans were supplemented by further restrictions arising from the policy of Coloured Labour Preference. It is because of these legislative constraints that resulted in a distortion and interference of migratory waves and trends that these two provinces offer a unique opportunity to do systematic research. Accordingly, the study identifies and analyses the primary changes in the direction and nature of internal migration streams into and within these provinces subsequent to the end of the apartheid regime and scrapping of such restrictive policies. Method: The main demographic and locational characteristics used in this analysis are changes in the size of the overall migration streams, their shifting mix of population groups (Black African, Coloured, Indian/Asian and White), the age of migrants, and the urban, peri-urban or rural nature of these migrants’ destinations. Migration data from three post-apartheid periods - 1996-2001, 2001-2006 and 2006-2011 – are analysed so as to enable comparisons of migrant flows between each of these periods. Findings: Comparing the net-migration rates during the earlier and latter post apartheid periods, both provinces reveal a deceleration in general mobility and in urbanisation, suggesting a slowing down in net migration flows in the latter period. Measuring and describing how migrants in these two provinces move, data pertaining to both inter-provincial migration (movement across provincial boundaries) and intra-provincial migration (movement within provincial boundaries but across municipal district boundaries) are considered. Although some variation in movement is illustrated for the two provinces, the data clearly illustrates continuing urbanisation in the settlement patterns of migrants for both migration flows. Considering the characteristics of migrants, the data illustrated migrants as mostly mature adults (30-60 years of age), except for in-migrants to the Western Cape who are mostly younger adults (20-29 years of age). The Black African population is the most mobile within inter-provincial migration streams, with the Coloured population the most active in intra-provincial flows. When comparing pre- and post-1994 internal migration trends in the two provinces, the dissertation illuminates three specific shifts, (i) a change in the political context within which mobility is framed, (ii) a change in the type of internal migration flows that are sustaining urbanisation and, (iii) a change in the profile, specifically pertaining to population group, of migrants mobile in the two provinces. The dissertation concludes by making a case for the adoption of a strategic and concerted approach by governments to accommodate the developmental constraints and challenges posed by these forms of human mobility.AFRIKAANSE OPSOMMING: Inleiding: Hierdie verhandeling fokus primêr op interne migrasie in post-apartheid Suid Afrika. Geografies fokus die tesis op twee van die land se huidige provinsies, naamlik die Noordkaap en die Weskaap. In beide hierdie provinsies het die apartheidsbeleid beperkinge geplaas op die vrye beweging van sekere Suid Afrikaners met verdere beperkings wat voortgevloei het uit die Kleurling Arbeidsvoorkeurwette. Dienooreenkomstig identifiseer en analiseer die studie primêre veranderinge in die rigting en die aard van interne migrasie strominge vanuit en na hierdie provinsies wat gevolg het op die beïndiging van die apartheidsregering (in 1994) en die gevolglike skrapping van hierdie wetgewing. Metode: Die hoof demografiese en vestigingskenmerke wat gebruik is in hierdie analise, hou verband met die verandering in die grootte van die oorkoepelende migrasie strominge, veranderinge in die samestelling van migrante, en die stedelik-, semi-stedelik, en landelike aard van die migrante se bestemmings. Migrante data van drie post-apartheidperiodes (1996-2001, 2201-2006 en 2006-2011) word gebruik om sodoende vergelykings te kan tref tussendie migrantevloei van beide hierdie periodes. Data wat betref beide inter-provinsiale migrasie (beweging oor provinsiale grense) sowel as intra-provinsiale migrasie (beweging binne provinsiale grense oor munisipale grense heen) word oorweeg. Bevindings: ‘n Vergelyking van die netto-migrasiekoers in beide provinsies gedurende die vroeër en later periodes, toon ‘n vertraging aan in beide interne en intra-provinsiale mobiliteit asook in verstedeliking, wat ‘n algemene vertraginging in die algemene migrasiestroom aandui. Te midde van variasie in die twee provinsies illustreer die data duidelike vestigingspatrone van migrante wat dui op volgehoue verstedeliking. Indien ouderdom en populasiegroep oorweeg word toon die data dat migrante meestal volwassenes tussen die ouderomme 20-29 jr is. Vergeleke met die ander populasie groepe is mobiliteit in die Swart populasie die hoogste binne inter-provisiale migrasiestrome teenoor die Kleurling populasie wat die hoogste mobiliteit binne intra-provinsiale migrasiestrome toon. Ten slotte lê die tesis ‘n argument voor wat aanvoer dat die bestuur van moontlike stremminge op ontwikkeling asook die ontsluit van moontlike ontwikkelingspotensiaal inherent tot migrasie, slegs moontlik is binne die raamwerk van ‘n doelbewuste strategie daarop gemik om die interaksie en assosiasie tussen migrasie en ontwikkeling in beleid en ontwikkelingsprosesse in te sluit

Scale model validation of QUAYSIM and WAVESCAT numerical models of ship motions

Thesis (MSc)--Stellenbosch University, 2015.ENGLISH ABSTRACT: Various numerical modelling software packages are available for predicting moored ship motions and forces. The focus of this study was to validate the numerical models QUAYSIM and WAVESCAT and how these models together form a procedure for predicting moored ship motions and forces under the impact of high and low frequency waves. The validation procedure applied in the study involved numerical modelling of a given physical model situation in which moored ship motions and forces were measured under both high and low frequency wave conditions. A physical model with built-in bathymetry was provided by the Council for Scientific and Industrial Research (CSIR) Hydraulics Laboratory in Stellenbosch. The model consisted of a moored container vessel at a jetty, with various mooring lines and fenders. A JONSWAP spectrum, which combines high and low frequency wave components, was used to simulate wave conditions for the modelling of ship motions. The wave periods and wave heights were measured at observation stations located at specific points in the basin. Other measurements such as those of the forces in the fenders and mooring lines were also determined. A multi-step approach was used to numerically predict the ship motions and forces. Firstly, the coastal processes occurring within the basin, which was set up to simulate the physical model wave behaviour, were measured to calibrate the SWAN Delft3D-WAVE model. The wave heights and periods for the respective observation stations were obtained and compared to the physical model measurements. The Delft3D-FLOW SURFBEAT model was used to calculate the low frequency waves in the coastal area. Low frequency waves are the main cause of larger ship motions and forces, therefore it is important to investigate them as part of the ship motion prediction procedure. After the waves had been computed, wave forces acting on the vessel needed to be determined for both high and low frequency waves. These wave forces were modelled with the combinations SURFBEAT/LF-STRIP (low frequency waves) and SWAN/WAVESCAT (high frequency waves). LF-STRIP provided the link between low frequency wave models and ship motion models, converting the low frequency waves into long wave forces acting on the vessel. WAVESCAT converted the high frequency waves to short wave forces. The calculated long wave forces and short wave forces served as the input required to run the ship motion model QUAYSIM to determine the movements of the moored ship as well as the restraining forces in the lines and fenders. The ship motions and forces were compared to the physical model, with the intention of possibly validating the QUAYSIM/WAVESCAT approach for predicting moored ship motions. The study provides an overview of both the setup and results of the physical and numerical model. A description of each of the numerical models SWAN, SURFBEAT, LF-STRIP, WAVESCAT and QUAYSIM is provided, along with a comparison between the physical and numerical models for each procedure. The validation procedure provided useful documentation of the quality of these numerical modelling approaches, already in use in some design projects. The numerical models WAVESCAT and QUAYSIM models of ship motion have shown to provide a good correlation between the physical model and the numerical approach. However, improvements are still required. Good comparisons were obtained for the long wave motions (horizontal movements - surge, sway and yaw). The surge and sway motions were slightly overestimated by QUAYSIM. The magnitude of the yaw was comparable but the not well represented in spectral plots.AFRIKAANSE OPSOMMING: Daar is verskeie numeriese modellering-sagtewareprogramme beskikbaar waarmee skipbewegings en -kragte voorspel kan word. Die fokus van hierdie studie was om die numeriese modelle QUAYSIM en WAVESCAT te valideer. Saam vorm hierdie twee modelle ’n prosedure om vasgemeerde skipbewegings en -kragte veroorsaak deur lang- en kortgolfaksie te bepaal. Die validasieprosedure wat in hierdie studie gebruik is, behels ’n numeriese modelering van ’n fisiese situasie waar ’n vasgemeerde skip se bewegings en kragte onder kort- en langgolfkondisies gemeet is. ’n Fisiese model met ingeboude batimetrie is voorsien deur die Council for Scientific and Industrial Research (CSIR) se hidroliese laboratorium in Stellenbosch. Die model bestaan uit ’n vasgemeerde houerskip by ’n pier met verskeie ankerlyne en bootbuffers. ’n JONSWAPspektrum, wat kort- en langgolfkomponente kombineer, is gebruik om golfomstandighede vir die modellering van skipbewegings te simuleer. Golfperiodes en golfhoogtes is by spesifieke waarnemingstasies in die gesimuleerde hawe-area gemeet. Verdere opmetings, soos dié van die kragte in die bootbuffers en ankerlyne, is ook gedoen. ’n Stap-vir-stap benadering is gevolg om die skipbewegings numeries te voorspel. Eerstens is die kusprosesse wat in die gesimuleerde hawe plaasvind, gekalibreer met die numeriese paket SWAN Delft3D-WAVE. Die golfhoogtes en golfperiodes vir elke waarnemingstasie is bereken en vergelyk met die fisiese model se opmetings. Die SURFBEAT-module van Delft3D-FLOW is gebruik om die lae-frekwensie golwe in die kusarea te bereken. Lae-frekwensie golwe is die hoofoorsaak van skipbewegings en daarom is dit belangrik om dit te ondersoek gedurende die voorspellingsprosedure van skipbewegings. Na die golwe bereken is, moes die kragte wat beide kort en lang golwe op die skip uitoefen ook bereken word. Hierdie golfkragte is gemodelleer deur middel van die kombinasies SURFBEAT/LFSTRIP (langgolwe) en SWAN/WAVESCAT (kortgolwe). LF-STRIP het die skakel tussen golfmodelle en skipbewegingsmodelle verskaf en die lae-frekwensie golwe omgeskakel in langgolfkragte wat op die skip uitgeoefen is. WAVESCAT het die hoë-frekwensiegolwe omgeskakel in kortgolfkragte wat op die skip uitgeoefen is. Die berekende langgolf- en kortgolfkragte is ingevoer op die skipbewegingsmodel QUAYSIM om die skipbewegings en inperkingskragte in die bootbuffers en ankerlyne te bepaal sodat dit vergelyk kon word met die fisiese model, met die doel om moontlik die QUAYSIM/WAVESCAT-prosedure om gemeerde skipbewegings te voorspel te valideer. Die studie verskaf ’n oorsig van die opstel en resultate van die fisiese en numeriese modelle. Elk van die numeriese modelle SWAN, SURFBEAT, LF-STRIP, WAVESCAT en QUAYSIM word beskryf en vergelykings word getref tussen die numeriese en fisiese modelle vir elke prosedure. Die validasieprosedure verskaf nuttige dokumentasie van die kwaliteit van hierdie numeriese modeleringsprosedures wat reeds in sekere ontwerpprojekte gebruik word. Die numeriese WAVESCAT en QUAYSIM modelle van skipbewegings het ’n goeie korrelasie tussen die fisiese model en die numeriese benadering gelewer. Verbeteringe is wel steeds nodig. Goeie vergelykings is verkry vir langgolfbewegings (horisontale bewegings – stuwing (“surge”), swaai (“sway”) en gier (“yaw”)). Die stu- en swaaibewegings was effens oorskat met QUAYSIM. Die grootte van die gier was wel vergelykbaar maar is nie grafies goed uitgebeeld nie

Deflections of reinforced concrete flat slabs

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2010.ENGLISH SUMMARY: It is found that the serviceability limit state often governs the design of slender reinforced concrete members. Slender flexural members often have a percentage tension reinforcement less than 1.0% and an applied bending moment just above the point of first cracking. For such members, the available methods to evaluate the serviceability conditions produce inadequate and unrealistic results. The evaluation of the serviceability of a slender member includes the calculation of the predicted deflection, either by empirical hand-calculation or analysing a finite element model, and the verification using the span-to-effective-depth ratio. The focus of the study is on flat slab structures. It investigates the different deflection prediction methods and the span-to-effective-depth ratio verifications from various design standards. These design standards include the ACI 318 (2002), the SABS 0100-1 (2000), the EC2 (2004) and the BS 8110 (1997). The background to the methods, as well as the parameters which influences the deflection development for lightly reinforced members, are investigated in order to define the limitations of the methods. As a result of the investigation of the deflection calculation methods, an Alternative Approach is suggested and included in the comparisons of the various methods. The deflection prediction methods and the span/effective depth verification procedures are accurately formulated to predict the serviceability behaviour of beams. Additional approaches had to be used to apply these methods to a two-dimensional plane such as that of a flat slab structure. The different deflection prediction methods and the span/effective depth verification methods are calculated and compared to the recorded data of seven experimental flat slab specimens as performed by others. A study by Gilbert and Guo (2005) accurately recorded the flexural behaviour of flat slab specimens under uniformly distributed loads for test periods up to 750 days. The methods to evaluate the serviceability of a slender member were also applied to slab examples designed using South African standards. The study concludes by suggesting a suitable deflection prediction method for different parameter (limitation) categories with which a slender member can comply to. The typical span/effective depth ratio trend is also presented as the percentage tension reinforcement for a slender member changes. It is observed that the empirical hand-calculation methods present more reliable results than those of the finite element models. The empirical hand-calculation methods are accurate depending on the precision to which the slab was constructed relative to the actual slab design. The comparison of the deflection methods with South African case studies identified the role played by construction procedures, material parameters and loading history on slab behaviour.AFRIKAANSE OPSOMMING: Die diensbaarheidstoestand is in baie gevalle die bepalende faktor vir die ontwerp van slank gewapende beton elemente bepaal. Slank elemente, soos lig bewapende buigbare beton elemente, het gewoonlik ‘n persentasie trekbewapening van minder as 1.0% en ‘n aangewende buigmoment net wat net groter is as die punt waar kraking voorkom. Die metodes beskikbaar om die diensbaarheid van sulke elemente te evalueer gee onvoldoende en onrealistiese resultate. Die evaluering van die elemente in die diensbaarheidstoestand sluit in die bepaling van defleksies deur berekening of die analise van ‘n eindige element model, en die gebruik van die span/effektiewe diepte metode. Die fokus van die studie is platbladstrukture. Die doel van die studie is om die verskillende metodes vir die bereking van defleksie asook die verifikasie volgens span/effektiewe diepte metodes van die verskillende ontwerp standaarde te ondersoek. Die ontwerp standaarde sluit die ACI 318 (2002), SABS 0100-1 (2000), EC2 (2004) en die BS 8110 (1997) in. Die agtergrond van hierdie metodes is ondersoek asook die parameters wat ‘n rol speel, sodat die beperkings van die metodes geidentifiseer kan word. As ‘n gevolg van die ondersoek na die beperkings van die metodes, is ‘n Alternatiewe Benadering voorgestel. Die Alternatiewe Benadering is saam met die metodes van die ontwerpstandaarde gebruik om die verskille tussen die metodes te evalueer. Die defleksievoorspelling en die span/effektiewe diepte verifikasie metodes is korrek geformuleer om die diensbaarheid van balke te evalueer. Ander benaderings was nodig om die diensbaarheid van blad blaaie te toets. Die onderskeie defleksievoorspelling en span/effektiewe diepte metodes is bereken vir sewe eksperimentele plat blaaie soos uitgevoer deur ander navorsers. Gilbert and Guo (2005) het ‘n studie uitgevoer waar die buigingsgedrag van die sewe plat blaaie, met ‘n uniforme verspreide las vir ‘n toetsperiode van tot 750 dae, akkuraat genoteer is. Die metodes om die diensbaarheid van ‘n slank element te toets, was ook op Suid-Afrikaanse blad voorbeelde getoets. Dit was gedoen om die Suid- Afrikaanse ontwerp van ligte bewapende beton elemente te evalueer. Die gevolgetrekkings stel ‘n gepaste defleksie metode vir ‘n slank element vir verskillende beperking kategorië voor. Dit is ook verduidelik hoe die tipiese span/effektiewe diepte verhouding met die persentasie trek bewapening vir ‘n slank element verander. Dit is bevind dat die imperiese handmetodes om defleksies te bereken, meer betroubaar as die eindige element modelle se resultate is. Die imperiese handberekening metodes is akkuraat relatief tot hoe akkuraat die blad konstruksie tot die blad ontwerp voltooi is. ‘n Vergelyking van defleksieberekening met Suid-Afrikaanse gevallestudies het die belangrikheid van konstruksieprosedures, materiallparamteres and belastingsgeskiedenis geïdentifiseer

An evaluation of the prediction of flat slab deflections

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A self-fulfilling prophecy : investigating the role of normative misperceptions in the student drinking culture at Stellenbosch University

Thesis (MA)--University of Stellenbosch, 2011.ENGLISH ABSTRACT: This thesis explores the existence of misperceptions regarding the peer‐drinking norm among undergraduate students at Stellenbosch University and the role of these misperceptions in explaining students’ drinking behaviour. A more permissive perception of the drinking norm has been associated with heavier alcohol consumption and negative consequences for oneself, others and property. Perceptions of the academic norm and its relation to personal academic and drinking behaviour are also investigated. Furthermore, the study examines the role of perceptions of the drinking norm in personal drinking behaviour in the context of other cognitive factors (perceptions), experiences prior to enrolling at university, as well as socio‐demographic and contextual factors. The theoretical framework used to understand the origin, occurrence and perpetuation of misperceptions regarding the social norm includes Bourdieu’s theory of habitus, social norms theory, social learning theory and attribution theory. Data were collected from 640 students out of a random sample of 3 177 who had been invited to participate in a web‐based survey during September 2009. In addition, 18 personal semi‐structured interviews were conducted with students.   Similar to findings of research in other countries, the results of this research show that students at Stellenbosch University tend to perceive other students’ drinking behaviour (descriptive norm) and approval of drinking behaviour (injunctive norm) as more permissive than their own. The degree of misperception increases as the social distance of reference groups increases and is also significantly related to personal alcohol consumption. There is also evidence of misperceptions regarding the academic norm and its association with personal drinking behaviour and academic behaviour. Multiple regression analysis reveals that the perceived drinking norm of close friends is the best predictor of personal drinking behaviour, followed by personal approval of drinking and drinking behaviour during the last year of high school. The data presented here for Stellenbosch University students extend the evidence that peer drinking norms are misperceived and highlights the importance of a student’s experiences before enrolling at university. Furthermore, it provides evidence that misperceiving the drinking norm is a pervasive problem that may have behavioural consequences. Various American higher education institutions have developed and implemented campaigns aimed at correcting these misperceptions. This has resulted in significant reductions in misperceptions as well as in heavy drinking among students. Students at Stellenbosch University and elsewhere might also benefit from these types of intervention strategies.  AFRIKAANSE OPSOMMING: Hierdie tesis ondersoek die bestaan van wanpersepsies aangaande die portuurgroep‐drinknorm onder voorgraadse studente aan Universiteit Stellenbosch en die rol daarvan in die verduideliking van studente se drinkgedrag. ’n Meer liberale persepsie van die drinknorm hou verband met swaarder alkoholgebruik en meer negatiewe gevolge vir die persoon self, ander en eiendom. Die studie ondersoek ook persepsies van die akademiese norm en die verband daarvan met persoonlike akademiese en drinkgedrag. Verder word die rol van persepsies van die drinknorm in persoonlike alkoholgebruik in die konteks van ander bewussynsfaktore (persepsies), ervarings voor inskrywing by die universiteit, asook sosiaal‐demografiese en kontekstuele faktore ondersoek. Die studie maak gebruik van die teoretiese raamwerke van Bourdieu se habitus, sosiale norm‐teorie, sosiale leer‐teorie en attributasieteorie om die oorsprong, aanwesigheid en voortsetting van wanpersepsies te verstaan. Data is versamel onder 640 studente uit ’n ewekansige steekproef van 3 177 studente wat uitgenooi was om gedurende September 2009 aan ’n webgebaseerde opname deel te neem. Daar is ook 18 in‐diepte semi‐gestruktureerde onderhoude met studente gevoer.   Soortgelyk aan bevindinge van navorsing in ander lande, toon resultate van hierdie navorsing dat studente aan Universiteit Stellenbosch geneig is om ander studente se drinkgedrag (beskrywende norm) en goedkeuring van alkoholverbruik (injunktiewe norm) as meer liberaal as hulle eie waar te neem. Die graad van wanpersepsie neem toe namate die sosiale afstand van verwysingsgroepe toeneem en hou ook betekenisvol verband met persoonlike alkoholgebruik. Daar is ook bewyse van wanpersepsies aangaande die akademiese norm en die verband daarvan met persoonlike drink‐  en akademiese gedrag. Resultate van ’n meervoudige regressie‐ontleding wys dat die waargenome drinknorm van goeie vriende die beste voorspeller van persoonlike drinkgedrag is, gevolg deur persoonlike goedkeuring van alkoholgebruik en drinkgedrag gedurende die laaste jaar van hoërskool. Die data van Stellenbosse studente lewer verder bewys dat portuurgroep‐drinknorme verkeerdelik waargeneem word en beklemtoon die belangrikheid van studente se vorige ervarings. Dit bewys ook dat die verkeerde waarneming van die drinknorm ’n konstante probleem is wat gedragsgevolge kan hê. Verskeie Amerikaanse universiteite het al veldtogte ontwikkel en geïmplementeer gemik op die regstel van dié wanpersepsies, en dit het wanpersepsies en swaar drankgebruik onder studente betekenisvol verminder. Studente aan Universiteit Stellenbosch en elders sal waarskynlik ook by soortgelyke intervensiestrategieë baat vind.jfl2011Imported from http://etd.sun.ac.z

Walking for Water Water Consumption in Unserviced Residential Areas in the Western Cape.

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