Nuwe bevindings oor die genetiese argitektuur van skisofrenie : die bydrae van studies onder Afrikaners : oorspronklike navorsing
Author Johannes L. Roos
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33, pp 1 –9 (2014) http://dx.doi.org/10.4102/satnt.v33i1.396
Die genetiese komponent in die etiologie van skisofrenie word reeds 'n geruime tyd al aanvaar. Die onderliggende argitektuur van die genetiese risiko bly 'n punt van bespreking. Vroeë studies oor koppeling en kandidaatverbintenis het grootliks gelei tot onoortuigende of onbesliste resultate. Meer onlangs het kragtige tegnologieë beskikbaar geword. Dít, tesame met groot genoeg toetsgroepe en genoomwye panele van genetiese merkers, het dit moontlik gemaak om sistematiese en agnostiese skandering te doen regdeur die genoom. In agnostiese skandering word tegnologie aangewend om die probleem op te los, sonder enige voorveronderstelling oor waar die genoomrelevante allele gevind sal word. Daar word gesoek na algemene en unieke siektevariante met onderskeidelik klein of groot effek. Die soektog na variante wat nie 'n groot effek het nie, het beperkte sukses gehad. Aan die ander kant het die rol van unieke genetiese gebeure, soos kopienommervariasie (KNV) en uniekepunt-mutasies al hoe belangriker geraak by geenontdekking in geval van skisofrenie. Onlangse navorsing onder Afrikanerpasiënte met skisofrenie, wat bou op vroeëre bevindings van spontane KNV by die 22q11 lokus, het lig gewerp op die spontane mutasieparadigma as 'n groot komponent in die argitektuur van skisofrenie. 'n Oorsig oor onlangse bevindings van hierdie studies word gegee.
Latest findings in the genetic architecture of schizophrenia: The contribution of genetic studies among Afrikaners.
Strategieë om die implementering van die Suid-Afrikaanse professionele leergemeenskapmodel te bevorder : oorspronklike navorsing
Authors: Christina J. Van Staden and Elsa Mentz
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33, pp 1 –8 (2014) http://dx.doi.org/10.4102/satnt.v33i1.776
Die Geïntegreerde Strategiese Beplanningsraamwerk vir Onderwyseropleiding en -ontwikkeling in Suid-Afrika 2011-2025 vereis dat vakverwante professionele leergemeenskappe tussen 2011 en 2017 op skool- en distriksvlak gevestig word. Die doel daarvan is om onderwysers van geleenthede te voorsien om hul eie leerbehoeftes te identifiseer en te vervul. Slegs sommige van die Distriksonderwysersontwikkelingsentra wat as vergaderplekke moet dien, hoef egter teen 2025 gereed te wees. Die gaping tussen beleid en die implemetering daarvan kan die vestiging van professionele leergemeenskappe rem en selfs verhoed. Drie implementeringsprobleme wat die professionele leergemeenskapmodel op die berugte onderwyshervormingsiklus kan stuur, word geïdentifiseer ten einde strategieë aan die hand te doen om die probleme op te los. Die ondersoek het tot die voorstel gelei dat 'n gekoördineerde benadering noodsaaklik geword het ten einde te verhoed dat die professionele leergemeenskapmodel die prooi van die berugte onderwyshervormingsiklus word.
Strategies for a smooth implementation of the South African professional learning community model
The Integrated Strategic Planning Framework for Teacher Training and Development in South Africa 2011-2025 requires that subject-related professional learning communities should be established widely between 2011 and 2017. However, only some of the District Teacher Development Centres that are intended to provide meeting places need to be up and running by 2025. The gap between policy and implementation can impede or even prevent the establishment of professional learning communities. Three implementation problems were identified that could catapult the professional learning community model into the infamous education reform cycle, and strategies are proposed for a smooth implementation. It is proposed that a coordinated strategy be followed to prevent the South African professional learning community model falling prey to the reform cycle.
Sintese en karakterisering van nuwe langketting-bimetaal-tetrakarboksielaatkomplekse : referaatopsomming
Authors: Ebraheim Botha and Elizabeth Erasmus
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1045
Synthesis and characterisation of new long alkyl chain bimetallic bridging tetra-carboxylate complexes. Palladium-based heterometallic complexes are important because of their interesting physical properties and excellent catalytic activity. In this study, four monometallic trinuclear palladium long chain carboxylates and four palladium-based bimetallic bridging tetracarboxylate complexes were synthesised. These complexes were characterised by different techniques, including DSC, TGA-MS, X-Ray diffraction and IR spectroscopy.
Bayes-beramers vir die gemiddelde van die normaalverdeling met onbekende variansie onder die LINEKS-verliesfunksie : referaatopsomming
Author Janet Van Niekerk
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33, pp 1 –2 (2014) http://dx.doi.org/10.4102/satnt.v33i1.936
Spesiëring van [ZrClx(OH).y(H2O)z]q deur elektrochemiese metings : referaatopsomming
Authors: Rone Kemp, Gerhard Lachmann, Derik J. Van der Westhuizen, Cornelius J. Le Roux and Henning M. Krieg
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1034
Speciation of [ZrClx(OH).y(H2O)z]q by electrochemical measurements. Speciation of zirconium complexes is important for liquid-liquid extraction of the metal. Spectrophotometry cannot be used as speciation method because d0-complexes form in an aqueous solution, and therefore the use of a chloride selective electrode is tested by firstly applying it to iron(III) chloride speciation, which is known.
Voorsiening van REST-dienste op mobiele Android-toestelle : referaatopsomming
Authors: Charl Van der Westhuizen and Marijke Coetzee
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1043
Provisioning of REST services on mobile Android devices. This research focuses on two approaches to host REST (Representational State Transfer) on mobile Android devices. A PAW Server for Android hosting a PHP (Hypertext Preprocessor) webpage with BeanShell scripting is one approach. Implementing a custom webserver for Android is another method to be considered.
Objektiewe beramers vir die gesensoreerde Rayleigh-model onder verskillende verliesfunksies : referaatopsomming
Authors: Johan T. Ferreira and Andriette Bekker
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33, pp 1 –2 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1040
Objective Bayesian estimators for the censored Rayleigh model using different loss functions. The censored Rayleigh model (with wide applications in notably survival analysis) is studied under extended loss functions, not previously considered, by deriving the Bayes estimators under these loss functions, and comparing them with a Monte Carlo simulation study via their risk functions using different objective priors.
Dubbelsinnige websoekstringe : 'n vergelyking van soekenjins en gebruikersinteraksies : referaatopsomming
Authors: Wynand Nel and Lizette De Wet
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1021
Au-nanopartikels met Ag-omhulsel vir CO2-elektro-reduksie : referaatopsomming
Author Retha Peach
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1020
Au@Ag core-shell nanoparticles for CO2 electroreduction. The purpose of this research project is to find an active binary metallic catalyst for the electrochemical reduction of CO2. Different gold-silver nanoparticles will be synthesised and characterised physically and electrochemically with the use of a rotating ring disk electrode (RRDE) to assess the catalytic activity towards CO2 reduction.
Sintese van amino-MIL-53(Al) met adsorpsie van ferroseen en ferroseenkarboksielsuur : referaatopsomming
Authors: Frederick H. Peens and Ernie H.G. Langner
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1019
Synthesis of amino-MIL-53(Al) with adsorption of ferrocene and ferrocenecarboxylic acid. Amino-MIL-53(Al) is an amino-functionalised derivative of the metal organic framework, MIL-53(Al). Synthesized with a solvo-thermal method, it has the ability to be functionalised and loaded with metal complexes. A new solvo-intrusion method was used to study the loading of ferrocene and amidation with ferrocenecarboxylic acid.
Die moontlikheid van membraangebaseerde vloeistofvloeistof-ekstraksie as skeidingsmetode vir Zr en Hf in waterige oplossings : referaatopsomming
Authors: Derik J. Van der Westhuizen, Gerhard Lachmann and Henning M. Krieg
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.938
The possibility of membrane-based solvent-extraction (MBSX) as a separation method for Zr and Hf in aqueous solutions. The focus of this study was to determine the suitability of this MBSX technology to purify and simultaneously concentrate Zr. It is known that Zr and Hf possess inherently slow chemical kinetic properties. However, by optimising the design and the operating conditions, we succeeded in removing Hf from the Zr solutes, while almost completely recovering the desired Zr.
Regioselektiwiteit in die palladium-gekataliseerde hidro-esterifisering van stilbene en verwante alkene : referaatopsomming
Authors: Maretha Du Plessis, Charlene Marais and Ben C.B. Bezuidenhoudt
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1006
Regioselectivity during the palladium catalysed hydro-esterification of stilbenes and related alkenes. This research is about the use of a catalytic process entailing the regioselective hydroesterification of 2-hydroxystilbenes followed by cyclisation to form the heterocyclic C-ring of the isoflavonoid skeleton. Regioselective influence of the electronic environment around the alkene substrate is limited therefore stilbenes with electron-withdrawing and electrondonating substituents on the two aromatic rings, were synthesised and subjected to palladium catalysed hydro-esterification.
Die sintetiese studie van nuwe Ru-komplekse en hul toepassing as katalisatore in organiese reaksies : referaatopsomming
Authors: Frederick P. Malan, Eric Singleton and Reinout Meijboom
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1033
'n Raamwerk vir 'n reputasiebestuuder in 'n hibridiese omgewing : referaatopsomming
Authors: Channel Hillebrand and Marijke Coetzee
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1037
A framework for a reputation manager in a hybrid environment. A reputation manager (RM) is created to regulate an environment. The purpose of this research is to create a configurable RM that can be implemented in various environments. The RM that is created is implemented in a hybrid environment and deployed on a cloud, and users also have a copy.
Toeganklikheid van die skool in jou omgewing : 'n konflik tussen ligging en kwaliteit, met die klem op Gauteng : referaatopsomming
Author Richelle Pienaar
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1017
Accessing one's neighbourhood school: A conflict between location and quality? The case of Gauteng. Neighbourhood schools do not always offer a quality education. This research investigates if there is a link between the location of a school and the quality education it offers, by making use of data such as the matric passrate, quantile ranking, teacher-learner ratio, school fees and the location of the school.
Organies-anorganiese hibriedverbindings van metaalhaliede : referaatopsomming
Author Cara Slabbert
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1003
Die molekulêre epidemiologie van rotavirus-infeksies in monsters ontvang van 'n privaat patologiepraktyk gedurende die 2010- en 2011-seisoen : referaatopsomming
Authors: Elizabeth M.C. Theron and John B. Dewar
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.998
Eksperimentele ondersoek van Rutenium- indenilideen prekatalisator vir 1-okteenmetatese : referaatopsomming
Authors: Quentin L. Steyl, Cornie C.G.E. Van Sittert and H.C. Manie Vosloo
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.1001
Experimental investigation of ruthenium-indenylidene precatalyst for 1-octene metathesis.Olefin metathesis entails the formation of new alkenes (olefins) by the breaking and reforming of C-C double bonds. Many metathesis catalysts have been developed of which the rutheniumindenylidene Grubbs type precatalyst is one. It showed an improvement on activity, stability and lifetime. The focus of this study is the optimisation of this precatalyst.
Skeiding van tantaal en niobium met vloeistof-vloeistof-ekstraksie : referaatopsomming
Authors: Maria J. Ungerer, Derik J. Van der Westhuizen, Gerhard Lachmann and Henning M. Krieg
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33, pp 1 –2 (2014) http://dx.doi.org/10.4102/satnt.v33i1.997
Separation of tantalum and niobium with solvent extraction. Niobium (Nb) and tantalum (Ta) have similar chemical and physical properties, which is why they are difficult to separate. They are found in various minerals of which the most important is columbite ([Fe, Mn, Mg] [Nb, Ta]2O6) and tantalite ([Fe, Mn][Nb, Ta]2O6). In this project various acids and extractants were investigated, in order to optimise the separation.
Vermindering van waterarmoede deur kartering met 'n fokus op gewigte : referaatopsomming
Source: Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 33 (2014) http://dx.doi.org/10.4102/satnt.v33i1.941
Reduction of water poverty through mapping with a focus on weightings. The aim of this paper is to describe how water poverty mapping can be used to assist the management of our already scarce water resources. It constructs a water poverty map, discusses the effect of incorrect weightings on the mapping process, and how the obtained map can be used to address water poverty.