Repetition overused as an academic writing strategy : a case study of Xhosa-English second language speakers

This study uses close linguistic analysis to investigate how a group of Xhosa English Second Language (XESL) Speakers use repetition as a discourse strategy in their written academic work. The study analyses the nature of their repetition and draws on critical theory to situate repetition in its socio-cultural context

A critical discourse analysis of the preambles of selected public documents with reference to racial classification

Magister Administrationis - MAdminOne of the most pertinent issues currently confronting South Africans and perhaps people around the world is the question of how to bring about social justice for everybody regardless of ‘races’, ‘ethnicities’, cultures, religions and genders. With this in mind, this study evaluates through a critical discourse analysis model the preambles of selected public policy documents in conjunction with the issue of racial classification as prescribed in the Z83 job application form in a post-apartheid South Africa. It draws specifically on Halliday’s (1978, 1989, and 2004) discourse analysis framework to evaluate the field and tenor of public discourse (what happened historically and who was involved in public policy formulations) and finally, the mode of public policy discourse (the part that language plays in the making of a new South African society). Moreover, it uses the education sector as an indicator of transformation to highlight the successes and failures of post-apartheid historical redress. It uses education as an exemplar because it ‘plays’ or has the potential to play a pivotal role in transformation and nation building in a post-apartheid South Africa. The study appraises particularly the impact of the notion of plurality of races as a transformation strategy; that is, its successes and failures in determining educational achievements numerically as well as nation building from 1994 to 2014. It uses close linguistic/discourse analysis to unravel the meaning(s) of ‘united in our diversity’ as well as associated concepts in the preambles of selected public policy documents. The reason for this is to show that the notion of different races is implicated in the concept ‘diversity’ in the preamble of South Africa’s constitution act 108 of 1996 as well as ‘designated groups’ in the preambles of affirmative action and Black Economic Empowerment (BEE) policies

Experimental and Computational Study on the Microfluidic Control of Micellar Nanocarrier Properties

Microfluidic-based synthesis is a powerful technique to prepare well-defined homogenous nanoparticles (NPs). However, the mechanisms defining NP properties, especially size evolution in a microchannel, are not fully understood. Herein, microfluidic and bulk syntheses of riboflavin (RF)-targeted poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG-RF) micelles were evaluated experimentally and computationally. Using molecular dynamics (MD), a conventional "random"model for bulk self-assembly of PLGA-PEG-RF was simulated and a conceptual "interface"mechanism was proposed for the microfluidic self-assembly at an atomic scale. The simulation results were in agreement with the observed experimental outcomes. NPs produced by microfluidics were smaller than those prepared by the bulk method. The computational approach suggested that the size-determining factor in microfluidics is the boundary of solvents in the entrance region of the microchannel, explaining the size difference between the two experimental methods. Therefore, this computational approach can be a powerful tool to gain a deeper understanding and optimize NP synthesis. © 2021 The Authors. Published by American Chemical Society

A volume of fluid (VOF) method to model shape change during electrodeposition

A novel volume of fluid (VOF) based approach is proposed to simulate the transient shape change of deposit front during electrodeposition considering secondary current distribution. Transport phenomena such as electrolyte potential, electric current density, and fluid flow of electrolyte are computed. The presented algorithm comprises computation of the exact VOF interface area as well as proposed modeling equations to accurately handle transport phenomena within the deposit. Based on the modeling results, it is essential to minimize the overshoot of electric current near the singularity between the cathode and insulator in the beginning stages of electrodeposition to achieve a relatively uniform thickness of the deposit layer in electroforming process. The results are validated against existing mathematical solutions

Enzymatic and structural characterization of HAD5, an essential phosphomannomutase of malaria-causing parasites

The malaria-causing parasite Plasmodium falciparum is responsible for over 200 million infections and 400,000 deaths per year. At multiple stages during its complex life cycle, P. falciparum expresses several essential proteins tethered to its surface by glycosylphosphatidylinositol (GPI) anchors, which are critical for biological processes such as parasite egress and reinvasion of host red blood cells. Targeting this pathway therapeutically has the potential to broadly impact parasite development across several life stages. Here, we characterize an upstream component of parasite GPI anchor biosynthesis, the putative phosphomannomutase (PMM) (EC 5.4.2.8), HAD5 (PF3D7_1017400). We confirmed the PMM and phosphoglucomutase activities of purified recombinant HAD5 by developing novel linked enzyme biochemical assays. By regulating the expression of HAD5 in transgenic parasites with a TetR-DOZI-inducible knockdown system, we demonstrated that HAD5 is required for malaria parasite egress and erythrocyte reinvasion, and we assessed the role of HAD5 in GPI anchor synthesis by autoradiography of radiolabeled glucosamine and thin layer chromatography. Finally, we determined the three-dimensional X-ray crystal structure of HAD5 and identified a substrate analog that specifically inhibits HAD5 compared to orthologous human PMMs in a time-dependent manner. These findings demonstrate that the GPI anchor biosynthesis pathway is exceptionally sensitive to inhibition in parasites and that HAD5 has potential as a specific, multistage antimalarial target

Strings on Bubbling Geometries

We study gauge theory operators which take the form of a product of a trace with a Schur polynomial, and their string theory duals. These states represent strings excited on bubbling AdS geometries which are dual to the Schur polynomials. These geometries generically take the form of multiple annuli in the phase space plane. We study the coherent state wavefunction of the lattice, which labels the trace part of the operator, for a general Young tableau and their dual description on the droplet plane with a general concentric ring pattern. In addition we identify a density matrix over the coherent states on all the geometries within a fixed constraint. This density matrix may be used to calculate the entropy of a given ensemble of operators. We finally recover the BMN string spectrum along the geodesic near any circle from the ansatz of the coherent state wavefunction.Comment: 41 pages, 12 figures, published version in JHE