Geldigheid vanuit drie paradigmas beskou: ’n eenheid, of ’n veelheid van perspektiewe?

Taaltoetse is hedendaags die norm aan hoëronderwysinstellings, hetsy vóór of ná toelating. Die effek van sulke toetse, of die besluite wat op basis van die resultate daarvan geneem word, kan tot in- of uitsluiting bydra. In ’n post-1994 Suid-Afrika is dit vanselfsprekend van belang dat ’n konsep soos ‘geldigheid’ deeglik ondersoek word, omdat die impak van voorafgenoemde toetse verreikend kan wees. Hierdie artikel bespreek daarom vanuit ’n filosofiese perspektief op die grondslae van die toegepaste taalkunde die begrip ‘geldigheid’ en definieer dit vanuit drie paradigmas, te wete ’n tradisionele paradigma, die hedendaagse/konvensionele siening en ’n meer aanvaarbare, verruimde,  standpunt daaroor. Die kern van die argument is dat geldigheid terselfdertyd ’n attribuut van ’n toets kan wees en as konstitutiewe begrip ontsluit kan word deur verdere (regulatiewe) idees met betrekking tot taaltoetsing. Dit word aan die hand van ’n teoretiese raamwerk gedoen wat op die konseptuele werk van Albert Weideman gebaseer is. Hierdie  raamwerk toon aan dat ’n veelheid van perspektiewe nodig is om   toegepaste linguistiese of tegniese ontwerpe (soos taaltoetse) opverantwoordbare wyse te gebruik.Sleutelwoorde: toegepaste taalkunde, taaltoetsing, geldigheid, validering,toetsattribuut, konstitutiewe begrippe, regulatiewe idee

Eerstejaarstudente en die P.U. vir C.H.O.

Na die Tweede Wêreldoorlog het daar in Suid-Afrika en feitlik alle ander lande ’n buitengewone toestroming van studente na universiteite en kolleges plaasgevind. Ná die V.S.A. is die toegangspersentasie van studente na ons Suid-Afrikaanse universiteite inderdaad die hoogste in die wêreld. Twee ondersoeke wat onafhanklik van mekaar in die R.S.A. uitgevoer is, het aangetoon dat oor ’n periode van 10 jaar meer as 80% van dié wat matrikuleer as universiteitstudente geregistreer word. In 1955 het dr. A. L. Kotzé, die huidige Direkteur van Onderwys in Transvaal, bekend gemaak dat 78% van dié leerlinge wat aan die einde van 1954 gematrikuleer het, tot inrigtings vir Hoër Onderwys toegetree het

Ses van die een en ‘n halfdosyn van die ander?

Die sentrum vir Akademiese en Professionele Taalpraktyk en die universiteitsbestuur van die Noordwes- Universiteit se Potchefstroomkampus ontvang gereeld navrae van studente en ouers oor die verpligte module Akademiese Geletterdheid (AGLA121) wat deur sommige leerders en ouers as ʼn duplisering van matriek Huistaal beskou word. Daar word aangevoer dat dié kursus ʼn negatiewe impak het op leerders se reeds beperkte studietyd. Daarom word die versoek dikwels gerig dat leerders wat A’s of B’s vir Afrikaans of Engels Huistaal in matriek gekry het, van die verpligte Toets van Akademiese Geletterdheidsvlakke (TAG), of die Engelse ekwivalent daarvan: die Test of Academic Literacy Levels (TALL), en AGLA121 vrygestel behoort te word. Die doel van hierdie artikel is om te bepaal of bogenoemde persepsie op feite gebaseer is en of die Noordwes-Universiteit (NWU) se Akademiese Geletterdheidskursus inderdaad slegs ʼn taalkursus is wat oorvleuel met dit wat reeds op skool onderrig is. Die artikel is hoofsaaklik konseptueel van aard. ʼn Ontleding word gemaak van die Curriculum and Assessment Policy Statement (CAPS) Graad 10-12, die konstruk van TAG wat akademiese geletterdheidsvlakke toets en die AGLA121-kursusinhoud om te bepaal in welke mate die inhoude van die matriek Huistaalsillabus ooreenstem met die konstruk van TAG en die kursusinhoude van AGLA121. Uit die studie behoort dit duidelik te wees of daar grootskaalse oorvleueling tussen CAPS aan die een kant en TAG en die AGLA121-module aan die ander kant is en of ʼn module in Akademiese Geletterdheid noodsaaklik is vir alle leerders op eerstejaarsvlak, omdat dit fokus op aspekte wat nie deur die skoolsillabus gedek word nie.Sleutelwoorde: akademiese geletterdheid, taalonderrig, huistaal, konstruk, universiteitskurrikulum, skoolsillabus, CAP

Towards informed decision making: the importance of baseline academic literacy assessment in promoting responsible university access and support

Low levels of academic literacy in the language(s) of teaching and learning are regarded as one of the main reasons for a lack of academic success amongst undergraduate students. Indeed, at Unisa, current concerns about the predictive validity of the National Senior Certificate has motivated a need for a reliable and valid instrument, used under standardised conditions, to measure the academic literacy levels of first year students. The aims of this project were to gather diagnostic data and empirical evidence about the current levels of academic literacy of prospective students of Unisa, and to identify specific reasons for their poor performance during the NQF5 in-service training. A quantitative research approach in the form of an interrupted time-series design was followed. A simple random sample of students, who underwent in-service training in 2009, was drawn, and the Test of Academic Literacy Levels (TALL) was employed as measuring instrument. T-tests were performed on the data to compare the actual differences between the pre- and post-test scores and regression analyses were used to determine the correlation between the two tests. The article concludes with recommendations on how language tests, like TALL, can assist higher education to make more informed, and thus responsible, decisions about issues of access.Lae vlakke van akademiese geletterdheid in die onderrig- en leertaal, of -tale, word beskou as een van die hoofredes vir gebrek aan akademiese sukses by voorgraadse studente. By Unisa het die heersende kommer oor die voorspellingsgeldigheid van die Nasionale Senior Sertifikaat inderdaad gelei tot ’n behoefte aan ’n betroubare en geldige instrument wat in vasgestelde omstandighede gebruik kan word om akademiese geletterdheidsvlakke onder eerstejaarstudente te meet. Die oogmerke met hierdie projek was om diagnostiese data en empiriese getuienis oor die bestaande akademiese geletterdheidsvlakke onder voornemende studente aan Unisa te versamel, en om spesifieke redes vir hulle swak prestasie tydens NKR 5-indiensopleiding uit te wys. ’n Kwantitatiewe navorsingsbenadering in die vorm van ’n onderbroketydreeks-ontwerp is gebruik. ’n Eenvoudige ewekansige steekproef is geneem van studente wat in 2009 indiensopleiding ondergaan het, en die Toets van Akademiese Geletterdheidsvlakke (TAG) is as meetinstrument gebruik. T-toetse is op die data uitgevoer om die werklike verskille tussen die voortoets- en natoetstellings te vergelyk, terwyl regressieontledings uitgevoer is om die korrelasie tussen die twee toetse te bepaal. Die artikel sluit af met aanbevelings oor hoe taaltoetse soos TAG hoër onderwys van hulp kan wees om meer ingeligte – en gevolglik meer verantwoordelike – besluite oor toelatingskwessies te neem.Keywords: academic readiness, academic literacy, first-year, Test of Academic Literacy Levels (TALL), throughput rates assessment, under-preparedness, university accessThe article is in English

Detection Of DNA Damage By Use Of Escherichia Coli Carrying recA\u27::lux, uvrA\u27::lux, And alkA\u27::lux Reporter Plasmids

Plasmids were constructed in which DNA damage-inducible promoters recA, uvrA, and alkA from Escherichia coli were fused to the Vibrio fischeri luxCDABE operon. Introduction of these plasmids into E. coli allowed the detection of a dose-dependent response to DNA-damaging agents, such as mitomycin and UV irradiation. Bioluminescence was measured in real time over extended periods. The fusion of the recA promoter to luxCDABE showed the most dramatic and sensitive responses. lexA dependence of the bioluminescent SOS response was demonstrated, confirming that this biosensor\u27s reports were transmitted by the expected regulatory circuitry. Comparisons were made between luxCDABE and lacZ fusions to each promoter. It is suggested that the lux biosensors may have use in monitoring chemical, physical, and genotoxic agents as well as in further characterizing the mechanisms of DNA repair

Oxidative Stress Detection With Escherichia Coli Harboring A katG\u27::lux Fusion

A plasmid containing a transcriptional fusion of the Escherichia coli katG promoter to a truncated Vibrio fischeri lux operon (luxCDABE) was constructed. An E. coli strain bearing this plasmid (strain DPD2511) exhibited low basal levels of luminescence, which increased up to 1,000-fold in the presence of hydrogen peroxide, organic peroxides, redox-cycling agents (methyl viologen and menadione), a hydrogen peroxide-producing enzyme system (xanthine and xanthine oxidase), and cigarette smoke. An oxyR deletion abolished hydrogen peroxide-dependent induction, confirming that oxyR controlled katG\u27::lux luminescence. Light emission was also induced by ethanol by an unexplained mechanism. A marked synergistic response was observed when cells were exposed to both ethanol and hydrogen peroxide; the level of luminescence measured in the presence of both inducers was much higher than the sum of the level of luminescence observed with ethanol and the level of luminescence observed with hydrogen peroxide. It is suggested that this construction or similar constructions may be used as a tool for assaying oxidant and antioxidant properties of chemicals, as a biosensor for environmental monitoring and as a tool for studying cellular responses to oxidative hazards

A BAYESIAN ANALYSIS OF THE AGES OF FOUR OPEN CLUSTERS

In this paper we apply a Bayesian technique to determine the best fit of stellar evolution models to find the main sequence turn off age and other cluster parameters of four intermediate-age open clusters: NGC 2360, NGC 2477, NGC 2660, and NGC 3960. Our algorithm utilizes a Markov chain Monte Carlo technique to fit these various parameters, objectively finding the best fit isochrone for each cluster. The result is a high precision isochrone fit. We compare these results with the those of traditional “by eye” isochrone fitting methods. By applying this Bayesian technique to NGC 2360, NGC 2477, NGC 2660, and NGC 3960 we determine the ages of these clusters to be 1.35 ± 0.05, 1.02 ± 0.02, 1.64 ± 0.04, and 0.860 ± 0.04 Gyr, respectively. The results of this paper continue our effort to determine cluster ages to higher precision than that offered by these traditional methods of isochrone fitting

Towards a responsible agenda for academic literacy development: considerations that will benefit students and society

The transition from secondary to higher education (HE) requires a change of cultural mindset (cf. Darlaston-Jones et al., 2003; Leki, 2006). It is widely accepted that the academic performance and motivation of first year students to stay in HE depend, among others, on how well they integrate into the university environment (Brinkworth et al., 2009). Academic integration or acculturation takes different forms. The premise of this article is that students have to learn to engage with academic discourse, i.e., they must acquire the community’s communicative currency, defined as different kinds of language used to reflect the community’s current norms, practices, values and expectations (cf., among others, Duff, 2010; Gee, 1998, 2000; Hyland, 2009). As reflective and responsible practitioners we therefore need to outline a critical agenda for academic acculturation by reviewing the debate on the nature of literacy and,  particularly, by discussing similarities and differences in epistemology and approaches to literacy. Such an agenda will have to recognise insights gained from, in particular, the New Literacy Studies (Street, 1998, 2004) and the Academic Literacies movement (Lea & Street, 1998; Lillis & Scott, 2007), but it will also become enriched by a linguistic perspective (Biber, 2006; Blanton, 1994; Bachman & Palmer, 1996; Halliday, 1978, 1985, 1993, 1996, 2002; Hyland, 2009). In developing a template for the agenda we accordingly acknowledge the theoretical defensibility and the feasibility of different approaches to academic acculturation.Keywords: academic literacy development, academic discourse, academic  acculturation or integration, higher educatio

BAYESIAN ANALYSIS OF TWO STELLAR POPULATIONS IN GALACTIC GLOBULAR CLUSTERS I: STATISTICAL AND COMPUTATIONAL METHODS

We develop a Bayesian model for globular clusters composed of multiple stellar populations, extending earlier statistical models for open clusters composed of simple (single) stellar populations (e.g., van Dyk et al. 2009; Stein et al. 2013). Specifically, we model globular clusters with two populations that differ in helium abundance. Our model assumes a hierarchical structuring of the parameters in which physical properties—age, metallicity, helium abundance, distance, absorption, and initial mass—are common to (i) the cluster as a whole or to (ii) individual populations within a cluster, or are unique to (iii) individual stars. An adaptive Markov chain Monte Carlo (MCMC) algorithm is devised for model fitting that greatly improves convergence relative to its precursor non-adaptive MCMC algorithm. Our model and computational tools are incorporated into an open-source software suite known as BASE-9. We use numerical studies to demonstrate that our method can recover parameters of two-population clusters, and also show model misspecification can potentially be identified. As a proof of concept, we analyze the two stellar populations of globular cluster NGC 5272 using our model and methods. (BASE-9 is available from GitHub: https://github.com/argiopetech/base/releases)