Die betekenis van die Moedertaalskool vir die nasionale vorming van ons jeug

Dit is van besondere betekenis vir die Afrikaner dat in die afgelope twee of drie jaar daar kort-kort ’n Afrikaansmediuniskool sy mondigwording gevier het. So het bv. die Hoër Voortrekkerskool op Boksburg twee jaar gelede reeds so’n fees gehad. So het die Hoër Monumentskool op Krugersdorp en die Helpmekaarskool op Johannesburg ook reeds hulle 21-jarige bestaan gevier. Van uit die Kaap-Provinsie kom die berig dat daar op Graaff-Reinet die mondigwording gevier word van die eerste skool met Afrikaans as voertaal in Kaapland, nl. die Hoër Volkskool

Analytical approximations of surface fields induced on convex scatters by exteriorly incident scalar fields

The boundary value problems for the Helmholtz equation give rise to boundary integral equations for the unknown surface field or its normal derivative. These integral equations involve the Helmholtz surface potentials in the form of weakly singular surface integrals. This thesis is based on a method of parameterisation of the surface integrals which removes the weak singularities provided that the surface satisfies certain convexity conditions. Firstly this method of parameterisation is applied to investigate the properties of the Helmholtz surface potentials on convex surface elements, and some new proofs are given. The theory is then applied to the boundary integral equations which arise when a scalar field is incident on a bounded scatterer. The surface integrals in these integral equations are Helmholtz potentials and can be regularised by suitable parameterisation. It is assumed that the unknoWn density function is an analytical function on the boundary of the scatterer, and can therefore be expanded as a Taylor series at any point of the surface. If this expansion is substituted into the regularised integral equation and if the operations of integration and summation are formally interchanged, then the end result is a partial differential equation of infinite order involving only the field coordinates and having analytical coefficients. However, if the Taylor expansions are truncated then partial differential equations of finite orders result. The view is taken that analytical solutions of such differential equations of finite orders can serve as _approximations for the surface field or its normal derivative provided that suitable initial conditions are imposed to ensure uniqueness. On the other hand the general solution of such a differential equation can serve as a local approximation at any point on the surface. Some basic properties of the differential equations and their solutions, called analytical approximations, are discussed and the theory is then applied to the problem of acoustic scattering from a sound hard sphere

Pressed to change: systematically reconsidering journalistic boundaries in the newsroom, boardroom and classroom

This thesis aims to present and reflect on a collection of research that has informed and shaped pedagogical and andrological praxis across the two decades since pioneers launched the first online news sites onto the World Wide Web, thereby setting off what is frequently described as a revolution in journalism. It makes a case for revisiting core principles of systems thinking to develop a holistic approach to reflecting on changing journalistic realities. A critical systems heuristic is then operationalised to consider how the diverse work in this portfolio reconsiders journalistic parameters in newsroom, boardroom and classroom situations that are both distinct and interrelated. In doing so it illustrates how a commitment to social and cultural fluidity can enable researchers to constructively engage with role players inside and outside of academic interpretative communities. Furthermore, in its suggestions for further research this study adds its voice to other calls for journalism scholars to extend the boundaries of their concern beyond the academy and to generate insights that empower individuals and impact on industry - to the ultimate benefit of society

Die generasie-interval, van die Suid-Afrikaanse vleismerino

The average generation interval of 3,53 years in S.A. Mutton Merino stud flocks in l96ll62 is the result of an average ram-age of 3,57 year sa nd an ewe-agco f 3,49 year s .I n 1971/72 the averagc 'agoef rams and ewesw as 3,86 and 4.13 year sr espec t i vel yw i th an averageg enerat ion interval of ' 4,00 years"T he e>l tendingo f the generat ioni nterval is mainly a resul to f an mcreaseo f 0,64 yearsi n the average age of ewes. The niost important factors leading to thc iatter are a smallcr annual replacement of ewes and the first mating of young ewes at a later age. The generation interval of difierent strata of thc breeding structure could not show a clear relationship between generation interval end the relative imporlanr-e of the flock.Die gemiddelde generasie- intervavia n 3,53 Jaar van S.A. .V leismer inostoetkuddesin l96l /62 is die resul taatv an'n genuddelde ramouderdorn van 3,57 jaar en"n ooioud,;rdonr van -r,49 jaar. In l97 ll72 was die gemiddelde ouderdom van ramme en ooie 3,86 e'n 4,13 jaar onderskeidel ikm et 'n gemiddeldeg cnerasre- intervavla n 4.00 jaar . Dic ver lengingv an die generasie- intervaisl hoofsaakl ikd ie gevolg van 'n toename van 0,64 Jaar rn die gcnriddelde ouderd()m van ooie. Die belangrikste faktore wat hiertoe gelei het is'n kleiner jaarlikse ooiverplasing en die eerstc paring van jong i,roic op 'ir lrrter ouderdom. Diegenerasie-interval van verskillende strata in die teeltstruktuurkon nie 'n duidelike verband tusren senerasie-interval en relatiewe belansrikheid van die kudde aandui nie

New palaeomacromiid dragonflies from the upper Paleocene of Argentina

A new genus of palaeomacromiid dragonflies, Curviarculia, based on Curviarculia delicata sp. nov. and Curviarculia lamasi sp. nov., is erected from the upper Paleocene Maíz Gordo Formation of north-western Argentina. Phylogenetic relationships within Palaeomacromiidae are discussed, leading to a new family diagnosis.Facultad de Ciencias Naturales y Muse

New palaeomacromiid dragonflies from the upper Paleocene of Argentina

A new genus of palaeomacromiid dragonflies, Curviarculia, based on Curviarculia delicata sp. nov. and Curviarculia lamasi sp. nov., is erected from the upper Paleocene Maíz Gordo Formation of north-western Argentina. Phylogenetic relationships within Palaeomacromiidae are discussed, leading to a new family diagnosis.Facultad de Ciencias Naturales y Muse

La parcimonie de Wagner sur base de caractères morphologiques: une nouvelle méthode pour les études paléosynécologiques

The limits and difficulties related to the tools currently in use for palaeosynecological comparisons of faunas or floras of different geological periods are discussed. The new method of the Wagner parsimony Applied to Palaeosynecology Using Morphology (WAPUM method), is defined and tested on morphological characters gathered from two insect groups Odonatoptera and Thripida. The difficulties related to the monophyly of the taxonomic groups used in the more traditional approaches are no longer a problem when using the WAPUM method. In the WAPUM a character is ‘presence versus absence of species bearing a morphological structure’. The results obtained from use of the WAPUM minimize the number of changes among character states. Application of the WAPUM could reveal signals to confirm or object the currently available scenarios for the global changes in the evolution of past diversity and disparity of organisms (major changes or global crises of diversity).Les limites et difficultés inhérentes aux outils actuellement utilisés dans les comparaisons paléosynécologiques de faunes ou de flores de différentes périodes géologiques sont discutées. La nouvelle méthode de la parsimonie de Wagner appliquée à la paléosynécologie sur la base de caractères morphologiques (méthode WAPUM), est définie et testée à partir des caractères morphologiques de deux groupes d’insectes, les Odonatoptera et les Thripida. Les difficultés liées à la monophylie des groupes taxonomiques utilisés dans les approches plus traditionnelles disparaissent avec la méthode WAPUM. Dans l’approche WAPUM, un caractère est ‘présence/absence d’une espèce portant une structure morphologique’. Les résultats obtenus à partir de la méthode WAPUM minimisent le nombre de changements d’état de caractères. Cet outil permet de tester les scénarios actuellement disponibles pour les changements globaux dans l’évolution de la diversité et de la disparité passée des organismes (changements majeurs ou crises globales de la diversité).Museo de La Plat

Inteelttoename by die S.A vleismerino en die verband met kuddegrootte

No Abstract

The first damselflies from the lowermost eocene of Denmark, with a description of a new subfamily (Odonata, Zygoptera: Dysagrionidae)

Eodysagrion mikkelseni gen. et sp. nov., type species of the new subfamily Eodysagrioninae, and the dysagrionine Primorilestes madseni sp. nov., the first thaumatoneurid damselflies from the lowermost Eocene of Denmark, are described. They confirm the presence of this American family in the Palaeogene of Western EuropeFacultad de Ciencias Naturales y Muse

The use of bioassays to assess the toxicity of sediment in an acid mine drainage impacted river in Gauteng (South Africa)

Abstract: Sediment contamination may occur from various anthropogenic activities, such as mining-, agricultural- and industrial practices. Many of the contaminants arising from these activities enter the aquatic system and precipitate from the surrounding water, becoming bound to sediment particles. These bound contaminants may reach concentrations higher than in the overlying water. Although water quality may be acceptable, an aquatic system may still be at risk if the contaminated sediment were to be disturbed through flooding, bioturbation or changes in the water chemistry. These contaminants may then desorb into the water column and prove detrimental to life forms in contact and dependent on that water source. Sediment quality monitoring has been a widespread international initiative and has led to the development of sediment toxicity assessment methods. This study focused on sediment bioassays, namely, Phytotoxkit, Ostracodtoxkit F and the Diptera bioassay, in assessing sediment quality of the Tweelopiespruit-Rietspruit-Bloubankspruit river system in Gauteng, South Africa. This river is known to have been impacted by acid mine drainage (AMD) since late August, 2002. Exposure of river sediment from 7 sampling sites to these bioassays provided an eco-toxicological estimation of the acute toxicity and chronic toxicity emanating from the contaminated sediments. Physico-chemical analyses revealed higher levels of sediment contamination closer to the mine. The bioassays displayed a similar trend with greater sensitivities to sediments closer to the mine and lower sensitivities to the less contaminated sites further downstream. AMD was therefore the main driver for sediment contamination. Whilst not all contaminants were bioavailable, statistical analysis showed that there were significant correlations between the elevated contaminant concentrations closer to the mine and bioassay responses