Evangelie*)

Min dinge is so gevaarlik as geestelike inteelt, as mens gedurig net met soort- en vakgenote omgaan. Dit is juis die unieke verryking van universiteitstudentwees: dat mens met kollegas uit alle studierigtings te doen kry. En in hierdie lig sien ek onder meer ook die Interfakultêre Lesings: Dit is ’n geleentheid om ’n slag saam as universiteitsgesin te praat oor iets anders as wat normaalweg in ’n mens se vakge- bied val. Iemand moet in sy vakgebied bly; en die slagoffer is ongelukkig die spre- ker. Maar hy behoort so te praat dat álle studente uit álle fakulteite álles kan ver- staan - en daarom moet u nie vanoggend van my ’n danige geleerde en vaktegniese betoog verwag nie. Ek vertrou wel dat wat ek in eenvoudige taal aan u gaan probeer stel, stewig op akademiese pote staan - my kombuiswerk het ek vir die kombuis gelaat

Die sogenaamde mondige mens en die jeug van vandag

Vergun my vooraf ’n paar persoonlike woorde: Die P.U. vir C.H.O. het my met hierdie uitnodiging ’n onverdiende eer aangedoen waarvoor ek ten seerste erkentlik is en dankbaar

Effect of a viscous fluid shell on the propagation of gravitational waves

In this paper we show that there are circumstances in which the damping of gravitational waves (GWs) propagating through a viscous fluid can be highly significant; in particular, this applies to Core Collapse Supernovae (CCSNe). In previous work, we used linearized perturbations on a fixed background within the Bondi-Sachs formalism, to determine the effect of a dust shell on GW propagation. Here, we start with the (previously found) velocity field of the matter, and use it to determine the shear tensor of the fluid flow. Then, for a viscous fluid, the energy dissipated is calculated, leading to an equation for GW damping. It is found that the damping effect agrees with previous results when the wavelength $\lambda$ is much smaller than the radius $r_i$ of the matter shell; but if $\lambda\gg r_i$, then the damping effect is greatly increased. Next, the paper discusses an astrophysical application, CCSNe. There are several different physical processes that generate GWs, and many models have been presented in the literature. The damping effect thus needs to be evaluated with each of the parameters $\lambda,r_i$ and the coefficient of shear viscosity $\eta$, having a range of values. It is found that in most cases there will be significant damping, and in some cases that it is almost complete. We also consider the effect of viscous damping on primordial gravitational waves (pGWs) generated during inflation in the early Universe. Two cases are investigated where the wavelength is either much shorter than the shell radii or much longer; we find that there are conditions that will produce significant damping, to the extent that the waves would not be detectable

A comparison of simple low-power wedge-type X-band waveguide absorbing load implementations

The original publication is available at http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4401506Stander, T., Van der Walt, P.W. & Meyer, P. 2007. A comparison of simple low-power wedge-type X-band waveguide absorbing load implementations, AFRICON 2007, Windhoek, September 26-28, doi:10.1109/AFRCON.2007.4401506.Two inexpensive waveguide absorbing loads are constructed and measured, each using a single thin resistive sheet absorber supported by styrofoam walls, and 50mm in length. It is found that a V-cut wedge displays less reflection than a tapered wedge, with -30 dB reflection across a band 8.5 - 12.4 GHz.Post-prin

Diskriminasie teen vroue in geloofsverband: 'n regsperspektief

Peer reviewedDiscrimination against women in religious context: a legal perspective South Africa’s Constitution not only protects the right to equality, but also guarantees freedom of religion. The crucial legal question is whether religious practices or structures within religious institutions that clearly discriminate against woman, will be regarded as matters of “pure faith” and offlimits for judicial scrutiny, thus exempting that religious community from the constitutional and statutory provisions on gender equality. Gender equality is an important and legitimate governmental objective, but the Constitutional Court recognises religion and religious belief as very personal, subjective matters that should be accommodated if possible. The challenge lies in balancing these contradictory rights in the diverse South African society. This is complicated, as it is not always possible to ascertain whether the discriminatory practices are indeed core elements of the religion or whether they stem from interpretation of religious principles by men in positions of authority.Research Institute for Theology and Religio

Electronic Cooling via Interlayer Coulomb Coupling in Multilayer Epitaxial Graphene

In van der Waals bonded or rotationally disordered multilayer stacks of two-dimensional (2D) materials, the electronic states remain tightly confined within individual 2D layers. As a result, electron-phonon interactions occur primarily within layers and interlayer electrical conductivities are low. In addition, strong covalent in-plane intralayer bonding combined with weak van der Waals interlayer bonding results in weak phonon-mediated thermal coupling between the layers. We demonstrate here, however, that Coulomb interactions between electrons in different layers of multilayer epitaxial graphene provide an important mechanism for interlayer thermal transport even though all electronic states are strongly confined within individual 2D layers. This effect is manifested in the relaxation dynamics of hot carriers in ultrafast time-resolved terahertz spectroscopy. We develop a theory of interlayer Coulomb coupling containing no free parameters that accounts for the experimentally observed trends in hot-carrier dynamics as temperature and the number of layers is varied.Comment: 54 pages, 15 figures, uses documentclass{achemso}, M.T.M. and J.R.T. contributed equally to this wor

What inspires South African student teachers for their future profession?

The need for an inspired professional teacher corps to haul South African school education out of its current low level of quality was the driving force behind this project. Its aim was to determine what counted as sources of inspiration for student teachers and hence for future teachers. Based on a conceptual-theoretical study, a questionnaire that could probe student teachers’ sources of inspiration was completed by a sample of student teachers (n = 1,683). A factor analysis of their responses revealed the following as their sources of inspiration, from most to least important: extended) family, religion, the teacher education institution, teaching practice, friends, and personal life. A comparison with similar research elsewhere revealed that, in this sample of respondents, considerations, such as education being the only accessible profession or being forced to enter the teaching profession because of economic circumstances, did not figure at all