Finding the missing variables: A systematic review of mathematics improvement strategies for South African public schools

The future of South Africa’s economic growth rests on addressing critical scarce-skills labour shortages. Matriculants are called on to break the cycle of poverty by entering the scarce-skills workforce. The demonstration of a high level of mathematics, science, and technology competency is viewed as a gateway towards achieving this goal. The South African Department of Basic Education has invested much effort towards improving mathematics, science and technology competencies among learners by implementing various mathematics improvement strategies in public schools. The existing research, however, shows that these initiatives have yielded little success among learners from impoverished schooling contexts. Reasons for this limitation were explored by means of the systematic review reported on in this paper. The review focused on literature relating to mathematics improvement strategies in public schools implemented by the South African Department of Basic Education. The limitations of these initiatives were critically evaluated and gaps in various documented strategies were identified. The findings highlight an evident need for a shift in focus of future interventions if the national goal to address scarce-skills labour demands through educating the impoverished South African youth is to be successfully realised. Suggestions are offered on how this change might happen.Keywords: critical variables; mathematics improvement strategies; social science; socio-economic inequality; South African public schools; underperformanc

BEHIND THE SEAMS: UNVEILING SOCIAL INJUSTICES IN A SCHOOL’S ENFORCEMENT OF PRESCRIBED DRESS RULES

Research on school drop-out rates in democratic South Africa cites school uniforms among the predominant causes of high school children, from impoverished contexts, dropping out of school. In light of this finding, this paper offers a critical examination of a school’s uniform rules against South Africa’s National Schools Uniform policy. Research data presented and discussed in this paper is drawn from a small scale case study, conducted in a working class South African school. Hermeneutics provided the analytical lens through which data were analysed. Critical theory offered a theoretical framework for data interpretation. The findings unearth social injustices which have become embedded in the schools dress code, when the national uniform policies were translated into school rules by a school’s leadership. The findings cannot be generalized to other schools. However, they do provide some insight into how children from impoverished backgrounds may be unfairly labelled, unjustly treated and possibly drop out of school, on account of the biased way in which a schools dress code expectations are decided on and enforced by a school’s leadership

Avoiding adsorption of DNA to polypropylene tubes and denaturation of short DNA fragments.

Two problems can arise when working with small quantities of DNA in polypropylene tubes: first, significant amounts of DNA can become lost by sticking to the tube walls; second, short DNA fragments tend to denature when binding to polypropylene. In addition, DNA also tends to denature upon dehydration. We have found that a simple way to solve these problems is by using polyallomer tubes instead of polypropylene and by avoiding certain salts, such as sodium acetate, when drying DNA

DNA loops and semicatenated DNA junctions

BACKGROUND: Alternative DNA conformations are of particular interest as potential signals to mark important sites on the genome. The structural variability of CA microsatellites is particularly pronounced; these are repetitive poly(CA) · poly(TG) DNA sequences spread in all eukaryotic genomes as tracts of up to 60 base pairs long. Many in vitro studies have shown that the structure of poly(CA) · poly(TG) can vary markedly from the classical right handed DNA double helix and adopt diverse alternative conformations. Here we have studied the mechanism of formation and the structure of an alternative DNA structure, named Form X, which was observed previously by polyacrylamide gel electrophoresis of DNA fragments containing a tract of the CA microsatellite poly(CA) · poly(TG) but had not yet been characterized. RESULTS: Formation of Form X was found to occur upon reassociation of the strands of a DNA fragment containing a tract of poly(CA) · poly(TG), in a process strongly stimulated by the nuclear proteins HMG1 and HMG2. By inserting Form X into DNA minicircles, we show that the DNA strands do not run fully side by side but instead form a DNA knot. When present in a closed DNA molecule, Form X becomes resistant to heating to 100°C and to alkaline pH. CONCLUSIONS: Our data strongly support a model of Form X consisting in a DNA loop at the base of which the two DNA duplexes cross, with one of the strands of one duplex passing between the strands of the other duplex, and reciprocally, to form a semicatenated DNA junction also called a DNA hemicatenane

High affinity binding of proteins HMG1 and HMG2 to semicatenated DNA loops

BACKGROUND: Proteins HMG1 and HMG2 are two of the most abundant non histone proteins in the nucleus of mammalian cells, and contain a domain of homology with many proteins implicated in the control of development, such as the sex-determination factor Sry and the Sox family of proteins. In vitro studies of interactions of HMG1/2 with DNA have shown that these proteins can bind to many unusual DNA structures, in particular to four-way junctions, with binding affinities of 10(7) to 10(9) M(-1). RESULTS: Here we show that HMG1 and HMG2 bind with a much higher affinity, at least 4 orders of magnitude higher, to a new structure, Form X, which consists of a DNA loop closed at its base by a semicatenated DNA junction, forming a DNA hemicatenane. The binding constant of HMG1 to Form X is higher than 5 × 10(12) M(-1), and the half-life of the complex is longer than one hour in vitro. CONCLUSIONS: Of all DNA structures described so far with which HMG1 and HMG2 interact, we have found that Form X, a DNA loop with a semicatenated DNA junction at its base, is the structure with the highest affinity by more than 4 orders of magnitude. This suggests that, if similar structures exist in the cell nucleus, one of the functions of these proteins might be linked to the remarkable property of DNA hemicatenanes to associate two distant regions of the genome in a stable but reversible manner

The microbiota of the gastro-intestinal tract: a biological compartment to explore in livestock species

In a perspective of safe, competitive and sustainable animal breeding systems, deepening animal phenotyping and defining new breeding goals are identified as major concerns. The intestine hosts a microbial ecosystem referred to as the gut microbiota. The gut epithelium, at the interface between the host and the microbiota, plays fundamental roles in nutrient absorption, local and systemic immune functions, as well as adaptive functions. The onset of high throughput sequencing methods have paved the way toward an unprecedented characterization of the microbiota by producing data on the non cultivable bacteria set. In livestock species, the scientific and technological context is in place to study the gut microbiota at both phylogenetic (bacteria diversity) and functional levels, and analyze the impact on shaping the host phenotypeL’élaboration de systèmes productifs et durables en élevage est une priorité. Dans ce contexte, il convient d’élargir le champ du phénotypage et d’identifier des leviers d’action. L’intestin héberge une communauté microbienne appelée microbiote intestinal. La muqueuse intestinale, à l’interface entre l’hôte et son microbiote, assure des fonctions vitales dans l’absorption des nutriments, dans l’équilibre immunitaire à la fois local et systémique, et dans la dynamique adaptative au cours de la vie. L’avènement de méthodes de séquençage à haut débit permet aujourd’hui de caractériser le microbiote intestinal avec une précision encore jamais atteinte, fournissant des données sur la portion bactérienne non cultivable. Chez les animaux d’élevage, le contexte scientifique et technologique est favorable pour mettre en place des projets qui croisent des informations individuelles liées au microbiote intestinal (diversité, écologie fonctionnelle) et à l’hôte (génétique, caractères zootechniques et cliniques, statut immunitaire), afin d’aborder de manière intégrée les nouveaux caractères à mesurer et améliore

Perceptions of violence among learners at a coeducational secondary school in Durban.

Thesis (M.Ed.)-University of Natal, Durban, 2003.This study concerns the perceptions of school-based violence amongst grade nine male and female learners in a working class high school in Durban. The school's racial dynamics has seen a change from a largely Coloured population to a majority Black school population. As an educator in the school and as a member of the community in which it is located, I am aware of several instances of violence within the school and the locale. I am also aware of several incidents that have been noted by community members whereby male and female learners have retaliated violently against those male and female educators who remain reliant on physically violent methods of classroom management. Former school-based policies aimed at curbing violence within this school have proved to be unsuccessful. In drafting these policies, not only have the school's management team failed to consider learner-perceptions regarding their experiences of violence - they have also failed to recognize the gender dimensions of violence. This study attempts to fill this gap. Research data was gathered by means of a semi- structured questionnaire in the form of essays in which my research sample were requested to reflect on their recent experiences of school-based violence. The data suggests that violence is a common occurrence at the school and impacts negatively on all learners. However, there are differences in the effects of violence on male learners as compared to the female learners. Some of the violence affirmed a violent hegemonic masculinity while girls also committed violence against other girls and boys. No effective strategies exist to counter the prevalence of violence in the school. This study shows why it is necessary to focus on the gendered nature of violence in schooling

The porcine Major Histocompatibility Complex and related paralogous regions: a review

The physical alignment of the entire region of the pig major histocompatibility complex (MHC) has been almost completed. In swine, the MHC is called the SLA (swine leukocyte antigen) and most of its class I region has been sequenced. Over one hundred genes have been characterised, including the classical class I and class I-related genes, as well as the class II gene families. These results in swine provide new evidence for the striking conservation during the evolution of a general MHC framework, and are consistent with the location of the class I genes on segments referred to as permissive places within the MHC class I region. Recent results confirm the involvement of the SLA region in numerous quantitative traits

Transcription variants of SLA-7, a swine non classical MHC class I gene

In pig, very little information is available on the non classical class I (Ib) genes of the Major Histocompatibility Complex (MHC) i.e. SLA-6, -7 and -8. Our aim was to focus on the transcription pattern of the SLA-7 gene. RT-PCR experiments were carried out with SLA-7 specific primers targeting either the full coding sequence (CDS) from exon 1 to the 3 prime untranslated region (3UTR) or a partial CDS from exon 4 to the 3UTR. We show that the SLA-7 gene expresses a full length transcript not yet identified that refines annotation of the gene with eight exons instead of seven as initially described from the existing RefSeq RNA. These two RNAs encode molecules that differ in cytoplasmic tail length. In this study, another SLA-7 transcript variant was characterized, which encodes a protein with a shorter alpha 3 domain, as a consequence of a splicing site within exon 4. Surprisingly, a cryptic non canonical GA-AG splicing site is used to generate this transcript variant. An additional SLA-7 variant was also identified in the 3UTR with a splicing site occurring 31 nucleotides downstream to the stop codon. In conclusion, the pig SLA-7 MHC class Ib gene presents a complex transcription pattern with two transcripts encoding various molecules and transcripts that do not alter the CDS and may be subject to post-transcriptional regulation