Kinetic simulations of X-B and O-X-B mode conversion

We have performed fully-kinetic simulations of X-B and O-X-B mode conversion in one and two dimensional setups using the PIC code EPOCH. We have recovered the linear dispersion relation for electron Bernstein waves by employing relatively low amplitude incoming waves. The setups presented here can be used to study non-linear regimes of X-B and O-X-B mode conversion.Comment: 4 pages, 3 figure

Case Study: Nutritional management of a patient with an open abdomen

No abstract

The Legacy of Daantjie Oosthuizen: Revisiting the Liberal Defence of Academic Freedom

No Abstrac

Emotional working memory training as a potential treatment for social anxiety disorder

Social anxiety disorder (SAD) is a debilitating psychological disorder characterised by the fear of being scrutinised by others, becoming embarrassed, offending others, and avoidance of social situations. SAD is highly prevalent, causes significant functional impairment, and is often comorbid with other anxiety and depressive disorders. Gold-standard evidence-based treatments for SAD (i.e., Cognitive Behavioural Therapy [CBT], antidepressants) have not provided the desired relief from social anxiety symptoms for many individuals with SAD. Therefore, the exploration of alternative interventions that are cost effective, easily accessible, autonomous, and provide flexibility with respect to incorporating treatment into one’s lifestyle is needed. Emotional working memory training (eWMT) shows potential as a treatment option for SAD due to: previous research finding significant positive outcomes (i.e., symptom decrease) when using forms of working memory training (WMT) in the treatment of anxiety-, depressive/mood- and stress-related disorders (AMS disorders), its ability to improve cognitive control of affective information, and its targeting of the prefrontal cortex of the brain - which is implicated in both working memory and SAD. Therefore, the broad aim of this program of research was to explore the efficacy of eWMT as a potential treatment for SAD. The overall results of this program of research suggests that, firstly, more rigorous studies are needed that evaluate forms of WMT in the treatment of AMS disorders/symptoms. Rigorous studies are needed to address the methodological and reporting issues identified in the systematic review, so that higher-quality evidence can be produced to evaluate WMT’s efficacy in future. Secondly, this program of research suggests that a 15-session x 20-minute course of eWMT has the potential to be used as an efficacious form of treatment to reduce SAD symptoms and may be comparable to gold-standard evidence-based treatments such as CBT. However, the efficacy of eWMT for SAD may be hindered by attitudes towards it, and to promote eWMT as a form of treatment for SAD, further strategies other than psychoeducation may need to be implemented to increase consumer engagement

Dealing with a traumatic past: the victim hearings of the South African truth and reconciliation commission and their reconciliation discourse

In the final years of the twentieth and the beginning of the twenty-first century, there has been a worldwide tendency to approach conflict resolution from a restorative rather than from a retributive perspective. The South African Truth and Reconciliation Commission (TRC), with its principle of 'amnesty for truth' was a turning point. Based on my discursive research of the TRC victim hearings, I would argue that it was on a discursive level in particular that the Truth Commission has exerted/is still exerting a long-lasting impact on South African society. In this article, three of these features will be highlighted and illustrated: firstly, the TRC provided a discursive forum for thousands of ordinary citizens. Secondly, by means of testimonies from apartheid victims and perpetrators, the TRC composed an officially recognised archive of the apartheid past. Thirdly, the reconciliation discourse created at the TRC victim hearings formed a template for talking about a traumatic past, and it opened up the debate on reconciliation. By discussing these three features and their social impact, it will become clear that the way in which the apartheid past was remembered at the victim hearings seemed to have been determined, not so much by political concerns, but mainly by social needs

Towards a developmental state? Provincial economic policy in South Africa

This paper explores the meaning of the developmental state for spatial economic policy in South Africa. Two main questions are addressed: do provincial governments have a role to play in promoting economic prosperity, and to what extent do current provincial policies possess the attributes of a developmental state? These attributes are defined as the ability to plan longer term, to focus key partners on a common agenda, and to mobilise state resources to build productive capabilities. The paper argues that the developmental state must harness the power of government at every level to ensure that each part of the country develops to its potential. However, current provincial capacity is uneven, and weakest where support is needed most. Many provinces seem to have partial strategies and lack the wherewithal for sustained implementation. Coordination across government appears to be poor. The paper concludes by suggesting ways provincial policies could be strengthened

Using a tree theme to develop language skills

A teaching prograrrrne is described in which trees are used as a unifying theme for developing language skills at the lower primary level

Emergency remote teaching and learning vs face-to-face: When are students more likely to fall behind?

The COVID-19 global pandemic brought about a shift from traditional face-to-face teaching and learning to emergency remote teaching and learning (ERT) in higher education institutions across the world. Prior studies have explored both instructor and student perceptions of ERT and identified self-regulated learning (SRL) as a major challenge. The question remains whether perceptions translate to student behaviour and if so, it will be important to address these self-regulation challenges as poor SRL has been linked to weaker academic achievement. This study investigated whether students exhibit inferior SRL strategies in ERT by falling further behind, as compared to a face-to-face setting. In order to measure how far behind students are, student access log-data from four undergraduate modules offered at Stellenbosch University in the 2019 (face-to-face setting) and 2020 (ERT setting) academic years were used. An analysis of variances model tested whether there was a difference in the number of days that students were behind for the two modes of teaching and learning. The results indicate that students are indeed more likely to fall behind during ERT as compared to face-to-face teaching and learning, thus exhibiting inferior SRL. This was statistically significant and pervasive across the different modules and time period investigated. These results will be of interest to higher education institutions as the onslaught of the pandemic has not only highlighted the need for improved ERT readiness, but it has also brought to the fore the need for a more digitally integrated offering as standard practice. Since it is unlikely that higher education institutions will return to a model identical to the pre-COVID-19 offering, this study contributes to finding the focus areas that will need to be addressed in a future hybrid model of teaching and learning

Analysis of Granular Flow in a Pebble-Bed Nuclear Reactor

Pebble-bed nuclear reactor technology, which is currently being revived around the world, raises fundamental questions about dense granular flow in silos. A typical reactor core is composed of graphite fuel pebbles, which drain very slowly in a continuous refueling process. Pebble flow is poorly understood and not easily accessible to experiments, and yet it has a major impact on reactor physics. To address this problem, we perform full-scale, discrete-element simulations in realistic geometries, with up to 440,000 frictional, viscoelastic 6cm-diameter spheres draining in a cylindrical vessel of diameter 3.5m and height 10m with bottom funnels angled at 30 degrees or 60 degrees. We also simulate a bidisperse core with a dynamic central column of smaller graphite moderator pebbles and show that little mixing occurs down to a 1:2 diameter ratio. We analyze the mean velocity, diffusion and mixing, local ordering and porosity (from Voronoi volumes), the residence-time distribution, and the effects of wall friction and discuss implications for reactor design and the basic physics of granular flow.Comment: 18 pages, 21 figure