Bakteriële populasieprofiele vanaf diesel verkry by vulstasies : original research
Authors: Eduard Venter, Phumzile Sibisi, Natasha Van de Haar and Adriaana Jacobs
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35, pp 1 –7 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1359
Mikrobiese groei kan plaasvind in opgebergde dieselbrandstof. Hierdie groei kan die latere benutting van die brandstof in voertuie en noodkragopwekkers beïnvloed deurdat dit brandstoffilters verstop. Verder kan 'n mutualistiese mikrobegemeenskap ontwikkel wat polisikliese aromatiese koolwaterstowwe (PAK) kan afbreek tot voordeel van mekaar. Dié projek se doelstelling was om die bakteriëlle gemeenskapsprofiel van gestoorde diesel te bepaal deur gebruik te maak van tegnieke wat beide die kweekbare en nie-kweekbare fraksies van die populasie bestudeer. Bakterieë en totale DNS is geïsoleer vanaf diesel en bestudeer deur gebruik te maak van denatureringsgradiënt jelelektroforese (DGGE) van die 16S ribosomale DNS (rDNS). Ses bakteriële stamme, afkomstig uit twee verskillende genera (verwant aan Bacillus en Lysinibacillus), is geïsoleer en kon as suiwer kulture groei met diesel as die enigste koolstofbron. Die DGGE-profiele het aangedui dat daar 'n verdere agt genera in die diesel voorkom. Beide die tegnieke het bakterieë geïdentifiseer wat verwant is aan Bacillus pumilus. Bacillus pumilus was die mees dominante spesie (50%) wat vanaf die kweekbare fraksie geïsoleer is. Die isolering van bakterieë wat voorkom in kommersieel verkrygde diesel kangebruik word om die graad van diesel afbraak tydens die berging daarvan te bepaal. Dit kan ook verder gebruik word om bioremediëring van diesel besoedeling te bewerkstellig.
Bacterial population profiling from diesel obtained from fuel stations. Microbial growth develops in stored diesel fuel. This can influence later use in emergency backup generators and vehicles through the clogging of fuel filters by the development of biomass. A mutualistic microbial community can develop in stored fuel products that degrade polycyclic aromatic hydrocarbons to the benefit of one another. This project aimed to study the bacterial community profile of diesel obtained from commercial fuel stations using culture dependent and independent methods. Bacteria and total DNA were isolated from the diesel and the community was studied using denaturing gradient gel electrophoresis of the 16S rDNA region. This resulted in the isolation of six bacterial species from two different genera (related to Bacillus and Lysinibacillus) that could grow in pure culture with diesel as carbon source. The denaturing gradient gel electrophoresis analysis indicated the occurrence of an additional eight genera in the sampled diesel. Both methods identified bacteria related to Bacillus pumilus occurring in the samples. Bacillus pumilus was the predominant species (50%) isolated from diesel samples using culture media. The identification of bacteria occurring in commercial diesel samples can be useful in determining the degree of degradation occurring during the storage of the product and also possible bioremediation agents in diesel fuels spills.
Van implementering tot verwesentliking : aanwending van resultate van internasionaal vergelykende studies : oorspronklike navorsing
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35, pp 1 –6 (2016)
Die prestasies van Suid-Afrikaanse leerders in internasionaal vergelykende studies bly voortdurend swak, wat vrae laat ontstaan oor die kwaliteit van onderwys wat aan Suid-Afrikaanse kinders gebied word in die verskillende grade en fases van formele skoolonderrig. Ernstige kommer oor leerders se swak prestasies oorheers navorsing en opvoedkundige debatte in Suid-Afrika. Ondanks goeie oogmerke, soos die hersiening van beleid en leerplanne, en die fokus op implementering, deur middel van kurrikulêre voorsiening en ondersteuning aan onderwysers, bly die verwesentliking in terme van leerders se prestasie teleurstellend swak. Hierdie studie ondersoek data verkry uit die preProgress in International Reading Literacy Study (prePIRLS) van 2011. Die prestasie van Suid-Afrikaanse Graad 4-leerders is op 'n punt van 461 bereken, wat beduidend laer is as die internasionale gemiddeld van 500 (SE = 3.7). Resultate van die prePIRLS 2011-studie word gebruik as bewys van die bereikingvan kurrikulêre doelwitte op die Graad 4-vlak, oor die spektrum van 11 Suid-Afrikaanse landstale. Norme of maatstawwe, soos afgelei uit die resultate, word verder ondersoek om moontlike verbeteringe aan te wys in die implementering van leerplanne in die klaskamer. Gevolgtrekkings sluit voorstelle in oor hoe onderwyspraktyk voordeel kan trek uit die bevindings van internasionaal vergelykende studies.
Bridging the gap from implementation to attainment: Utilising results from international comparative studies. South African learner performance in international comparative studies remains persistently poor, resulting in questions about the quality of education offered to South African children across grades and phases of formal schooling. In South Africa, grave concerns with regard to low levels of learner achievement pervade research initiatives and educational debates. Despite good intentions (such as policy and curricular reforms) and focus on implementation (such as curriculum provision and teacher support), attainment (in the form of learner achievement) remain disappointingly low. This study draws on the preProgress in International Reading Literacy Study (prePIRLS) 2011 data, which places South African Grade 4 learners' results at 461, which is substantially below the international centre point of 500 (SE= 3.7). Results from the prePIRLS 2011 study are used as evidence of curricular attainment that has taken place at Grade 4 level across a spectrum of 11 languages in South Africa. Benchmark results are further interrogated to provide evidence for possible improvement of curricular implementation at classroom level. Concluding remarks include reflections of how teacher practice can benefit from evidence provided by international comparative studies.
Faktore wat onderwysers se gebruik van GeoGebra vir Wiskundeonderrig beïnvloed : oorspronklike navorsing
Authors: Gerrit H. Stols, Stephan J. Venter and Elizabeth M. Louw
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35, pp 1 –8 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1366
Hierdie studie het ondersoek gedoen na faktore wat onderwysers se gebruik van wiskundesagteware (in hierdie geval GeoGebra) vir onderrig en leer beïnvloed. Deelnemers aan die studie is by wyse van doelsteekproeftrekking geselekteer uit 'n groep onderwysers wat sagtewareopleiding ontvang het, toegang tot rekenaars het en met die sagteware vertroud is. Vyf-en-sewentig respondente het die gestruktureerde vraelyste voltooi. Veelvoudige regressie is gebruik om die verhouding tussen die vier konstrukte van die Unified Theory of Acceptance and Use of Technology te ondersoek. Hierdie konstrukte is prestasieverwagting, verwagte inspanning, sosiale invloed en fasiliterende omstandighede met betrekking tot onderwysers se voorneme om die wiskundesagteware te gebruik. Die studie het bevind dat die kombinasie van die vier bogenoemde konstrukte 30% van die variansie in respondente se voorneme om die sagteware te gebruik verduidelik het. Daar is gevind dat fasiliterende omstandighede in die studie nie regstreeks 'n invloed op mense se gebruik, al dan nie, van die sagteware het nie, aangesien almal van hulle toegang tot rekenaars het. Die sosiale invloed is die enigste konstruk wat die voorneme om GeoGebra te gebruik direk beïnvloed het. Onderwysers se voorneme om sagteware te gebruik het geblyk die werklike gebruik van sagteware vir onderrig en leer te voorspel.
Factors that influence teachers' use of GeoGebra for instruction
This study investigated factors that influence teachers' use of mathematics software (in this case GeoGebra) for teaching and learning. Participants in the study were purposefully selected from a group of teachers that have received software training, have access to computers, and are familiar with the software. Seventy-five respondents completed the structured questionnaires. Multiple regressions were used to investigate the relationship between the four constructs of the Unified Theory of Acceptance and Use of Technology. These constructs are performance expectancy, effort expectancy, social influence, and facilitating conditions on teachers' intention to use the mathematics software. This study found that the combination of the four above mentioned constructs explained 30% of the variance in respondents' intention to use the software. Facilitating conditions were not found to directly influence whether or not people actually used the software because all of them have access to computers. Teachers' intention to use GeoGebra was found to predict the actual use of GeoGebra for teaching and learning.
Verbruikerstudie-onderwysstudente se affektiewe ervarings tydens projekgebaseerde leer : oorspronklike navorsing
Authors: Adri Du Toit, Marietjie Havenga and Marthie Van der Walt
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35, pp 1 –9 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1362
Die implementering van projekgebaseerde leer het die potensiaal om affektiewe faktore in studente positief te ontwikkel wat selfgerigte lewenslange leer kan bevorder. Lewenslange leer is 'n sleutelvereiste vir onderwysers om relevant kundig in hulle vakgebied te bly, asook om aan die vereistes te kan voldoen wat aan leerders en onderwysers in die 21ste eeu gestel word. Dit is veral belangrik vir onderwysers wat Verbruikerstudie, 'n dinamiese en waardevolle vak in Suid-Afrikaanse skole, aanbied. Die bevordering van selfgerigte lewenslange leer as deel van die opleiding van Verbruikerstudie-onderwysstudente is dus noodsaaklik. Verskillende affektiewe faktore, byvoorbeeld motivering, dra by tot die bevordering van leer wat ontwikkel kan word deur die keuse van gepaste onderrig-leerstrategieë. Affek kan leer deur geheueprosesse, leerprosesse, aandagspan, ervarings en motivering beïnvloed. 'n Gevallestudie is onderneem om ondersoek in te stel op welke wyse projekgebaseerde leer in 'n opleidingsprogram vir Verbruikerstudie-onderwysstudente bydra tot die ontwikkeling van affektiewe faktore en hoe dit hulle leer bevorder. Studente wat vir 'n Verbruikerstudieopleidingsprogram geregistreer is, is as deelnemers geselekteer en data is deur middel van oop vraelyste, weeklikse refleksie, asook fokusgroep- en individuele onderhoude ingesamel. Die bevindinge bevestig dat die toepassing van projekgebaseerde leer bygedra het tot die bevordering van verskeie affektiewe faktore, maar in die besonder motivering, die waarde wat die studente aan leer heg, asook die ontwikkeling van 'n positiewe houding jeens leer. Hierdie affektiewe faktore dra by tot die ontwikkeling en bevordering van positiewe leerervarings. Ontwikkelaars van voorbereidingsprogramme vir Verbruikerstudie-onderwysstudente sou hierdie inligting kon implementeer ter versterking van sulke programme. Verdere navorsing kan gedoen word aangaande die verband tussen projekgebaseerde leer en ander affektiewe faktore wat leer kan ondersteun in Verbruikerstudie-onderwysersopleiding.
Consumer Studies student teachers' affective experiences during project-based learning
The implementation of project-based learning has the potential to develop affective factors positively in students, which may foster self-directed lifelong learning. Lifelong learning is a key requirement for teachers to keep current and knowledgeable in their fields of expertise, as well as to satisfy the demands set for learners and teachers in the 21st century. This is especially important for teachers in Consumer Studies - a dynamic and valuable subject in South African schools. Promoting lifelong, self-directed learning as part of the training of Consumer Studies student teachers is therefore essential. Several affective factors, for example motivation, contribute to the promotion of learning and can be developed through the selection of appropriate teaching-learning strategies. Affect can influence learning through memory processes, learning processes, attention span, experiences and motivation. A case study was undertaken to investigate how project-based learning contribute to affective factors within an existing university training programme for Consumer Studies student teachers and how it promotes their learning. Students registered for a Consumer Studies teacher preparation programme were selected as participants and data collected by means of open-ended questionnaires, weekly reflections, as well as focus group and individual interview sessions. Findings indicate that the application of project-based learning promoted affective factors in the student teachers, especially motivation, the value they placed on learning, as well as the development of a positive attitude towards learning - all of which contribute to the promotion and development of positive learning experiences. Developers of preparation programmes for Consumer Studies student teachers could implement this information to enhance such programmes. Possibilities exist for further research regarding the connection between project-based learning and other affective factors contributing to learning in Consumer Studies student teacher preparation programmes.
223Ra calixareen-krooneterverbindings met teenligaampies as radiofarmaseutiese middels vir die behandeling van kanker : referaatopsomming
Authors: J. Ackermann, A. Muller, J. Ackermann, D. Jansen, N. Jarvis and J-R. Zeevaart
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1406
223Ra calixarene-crown ether antibody conjugates as potential radiopharmaceuticals for the treatment of cancer
Radium possesses a self-directing capability to accumulate in bones for treatment of bone cancer. The treatment of other cancers requires a method that will shield the Ra from bone absorption and direct it towards specific cancers. This study investigates the probability of tailored Ra/Ba-calixarene systems for such purposes.
Die omgewingsimpak van drywende sonkragstelsels in die wynbedryf : referaatopsomming
Authors: F.C. Prinsloo and A. Lombard
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1424
The environmental impacts associated with floating solar systems in the wine industry
For sustainable wine farming the main aim is to minimise environmental impact and to ensure sustainability and economic viability through environmentally sound production practices. This study evaluates the environmental impact of integrated over-water vineyard irrigation solar energy solutions in winery production systems and shows that floating solar systems on vineyard irrigation ponds in the Western Cape wine region may ensure positive environmental impact benefits.
Die sintese, karakterisering, elektrochemiese eienskappe en katalitiese toepassing van nuwe [CpNiBr(NHK)]-komplekse : referaatopsomming
Authors: F.P. Malan, E. Singleton, M. Landman, P.H. Van Rooyen and J. Conradie
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35, pp 1 –2 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1423
The synthesis, characterisation, electrochemistry, and the catalytic application of new [CpNiBr(NHC)] complexes
A range of symmetric and asymmetric aliphatic-arene NHC ligands has been synthesised and reacted with NiCp2 to form [CpNiBr(NHC)] complexes in high yield (&gt; 72%). A direct relationship between their electrochemical properties derived from cyclic voltametry and their catalytic activity in the Suzuki-Miyaura coupling reaction has been found.
Elektrochemiese en adsorpsiestudies van die metaalorganiese netwerk, NH2-MIL-53(Al) : referaatopsomming
Authors: F.H. Peens and E.H.G. Langner
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1422
Electrochemical and adsorption studies of the metal organic framework, NH2-MIL-53(Al)
NH2-MIL-53(Al) is an amino-functionalised derivative of the metal organic framework MIL-53(Al). When successfully synthesised, it has the ability to be functionalised with metal complexes. A new solvo-intrusion method was used to study the amidation with butyric acid and ferrocenecarboxylic acid.
Authors: E.C.M. Maritz, S. Dorfling and T. Vetrik
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1420
A clever colouring game in graph theory
In this study we focus on a generalised colouring of graphs, namely a metric chromatic colouring. We determine new upper bounds for the metric chromatic number of wheels and circulant graphs and show that these boundaries are an improvement on existing values.
Die gebruik van bliknavolging om te bepaal of ervaring in kartografie en kaartontwerp 'n invloed het op die spoed, benadering en korrektheid van kaartinterpretasie : referaatopsomming
Authors: D.J.M. Hoffman, P.J. Blignaut and C.H. Barker
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35, pp 1 –2 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1419
Using eye-tracking to assess the effect of cartographer expertise and map design on the speed, approach and correctness of map interpretation
This study used a head-mounted eyetracker to investigate the effects that cartographer expertise and map design can have on map interpretation. The final results indicate that map design has a significant effect on map interpretation. Cartographer expertise does not have any significant effect on map interpretation.
Argitektuur vir die proaktiewe verkryging en analise van forensiese inligting in wolkstelsels : referaatopsomming
Authors: D.J. Ras and H.S. Venter
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1418
Architecture for the proactive acquisition and analysis of forensic information in cloud systems
Cloud systems have to deal with massive amounts of distributed, volatile data which makes forensic investigations difficult. Using the NIST reference architecture, a system is devised to proactively capture forensic data that can be used in an investigation. The system proposes using nested virtual machines with forensic capabilities.
'n Ondersoek na die opgewekte elektroniese toestande van karotenoïede in die hoofligversamelingskompleks van plante (LHCII) deur femtosekondepompproefspektroskopie : referaatopsomming
Authors: A. Singh and T.P.J. Kruger
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35, pp 1 –2 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1417
Investigating the excited electronic states of carotenoids in the main plant lightharvesting complex (LHCII) via femtosecond pump-probe spectroscopy
Photosynthesis involves the main plant light-harvesting complex (LHCII) pigments (chlorophylls and carotenoids). These pigments absorb and transfer photoenergy to lower excited electronic energy states. Carotenoids protect plants against over-illumination. The ultrafast dynamics of carotenoid excited states in spinach leaves were investigated upon intensity-dependent, selective carotenoid excitation through femtosecond pump-probe spectroscopy.
Die ontleding van endokrienontwrigtende chemikalieë in water met behulp van sorptiewe ekstraksie, GCÃ?GC-TOFMS en UPLC-MS/MS : referaatopsomming
Authors: M. Wooding, N. Aneck-Hahn, R. Bornman, E. Rohwer and Y. Naude
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1416
Analysis of endocrine disrupting chemicals in water by sorptive extraction, GCÃ?GCTOFMS and UPLC-MS/MS
In this study, methods have been developed to detect endocrine disrupting chemicals in surface and drinking water. Pollutants were concentrated from water, using sorptive extraction, followed by analysis with comprehensive gas chromatography - time-of-flight mass spectrometry (GCÃ?GC-TOFMS) and ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS).
Authors: M. Van Straaten and S. Ter Horst
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1415
The strong Parrott's lemma
A study was done using matrix analysis to find the necessary and sufficient conditions for a given partial matrix to be completed to a contraction and the form of the unspecified entry in the partial matrix. An extention to this (Parrott's lemma) is also obtained which gives an extra condition.
Edelmetaalkataliste op metaaloksiedondersteuningsmateriaal deur 'n gesamentlike presipitasiemetode vir laetemperatuur- selektiewe hidrogenering : referaatopsomming
Authors: S.J. Gerber and E. Erasmus
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1414
Noble metal catalysts on metal oxide support by co-precipitation for low-temperature selective hydrogenation
The selective catalytic hydrogenation of α, β-unsaturated aldehydes is a useful transformation in organic synthesis to produce fine chemicals. The formation of allylic alcohols by hydrogenation of the carbonyl of α, β-unsaturated aldehydes are extremely valuable intermediates in the fragrance, flavouring and pharmaceutical industry.
'n Vloeichemiestrategie vir die sintese van neurologiese farmaseutiese middels : referaatopsomming
Authors: N.C. Neyt and D.L. Riley
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1413
Utilising flow technology to synthesise neurological active pharmaceutical ingredients
A flow-through strategy for the synthesis of clozapine under pressurised, superheated conditions using a Uniqsis Multi-X flow chemistry system which demonstrates improvements over the conventional batch route. Synthesis of clozapine characteristically involves a four-step synthesis. These key steps are applicable to many other syntheses and have already shown remarkable improvements over the traditional batch process routes.
Sintese, karakterisering en elektrochemie van osmoseenbevattende alkohole : referaatopsomming
Authors: M. Govender, J.C. Swarts and E. Muller
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35, pp 1 –2 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1412
Synthesis, characterisation and electrochemical studies of osmocene-containing alcohols
A series of osmocene-containing carboxylic acids, Oc(CH2)mCOOH, where m = 1, 2 and 3, and osmocene-containing alcohols, Oc(CH2)nOH, where n = 1, 2, 3 and 4, were synthesised and characterised, using 1H NMR spectroscopy and infrared spectroscopy. Cyclic voltametric studies on the series of alcohols and carboxylic acids demonstrated a decrease in the formal reduction potential (E°') as the number of -CH2- spacers increased. The crystal structures of 2-osmocenylacetonitrile and 2-osmocenylethanol were determined by single-crystal X-ray crystallography.
Bepaling van die optotermiese eienskappe van La2O2S:Eu fosformateriaal : referaatopsomming
Authors: L.J.B. Erasmus, J.J. Terblans and H.C. Swart
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1410
Measuring the optical thermometry properties of La2O2S:Eu phosphor material
This presentation is focused on the investigation of the optical thermometry properties of lanthanum oxysulphide doped with europium by utilising photoluminescence. After a literature study it was concluded that optical thermometry properties of phosphor materials can be measured by several techniques. The technique discussed is the fluorescence intensity ratio technique.
Author L. Van der Walt
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35, pp 1 –2 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1409
This project aims to build a fully functioning mobile system that can complete daily business tasks and to make more advanced technology easier and faster available to employees. An MDS system that enables a user to make quick decisions and shows valuable information is a big benefit to a business.
Authors: J.M. Maritz and P.J. Meintjes
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 35 (2016) http://dx.doi.org/10.4102/satnt.v35i1.1408
Pulsars as jittery timers
Our current model of pulsars is incomplete due to the lack of a full description of the radiation mechanism. Pulsars can be used as accurate timekeepers, but owing to limited technology and timing errors, the current timing model of pulsars remains a challenge. We discuss the timing of PSR J1326-5859 and the challenges that can be expected.