University of Cape Town
  • Cape Town, South Africa
Recent publications
There has been an exponential uptake of digital technology in the past decade, and especially since the outbreak of the COVID-19 pandemic. Much of the research has focused on the possible adverse effects of escalating digital technology use on child and adolescent development, with few studies investigating the potential benefits of digital technology use for children and adolescents. This chapter examines the effects (positive and negative) of digital technology use on adolescent resilience focusing on social involvement, intrapersonal functioning, and brain development in adolescence. In addition, sex and age-related differences, and the ameliorating effect of mindfulness practices on digital technology overuse are discussed, along with the interaction of digital technology within mindfulness practice. While this chapter looks at digital technology use in general, we acknowledge that different types of digital technology may affect adolescent development and resilience in diverse ways.
There is a growing need to understand the role of non-cognitive factors in relation to university students’ academic performance and successful adaptation to university life. This study investigated the relationship between the non-cognitive factor “resilience” and student success (academic performance, turnover intentions, brain-body optimisation) among South African university students. This cross-sectional correlational study analysed data from 360 first-year students. Self-report data were collected using the Neurozone Assessment, comprising two subscales: the Brain Performance Diagnostic and the Resilience Index. Turnover intentions were assessed using the Neurozone Assessment, and students’ academic marks were obtained via the university’s management information system. Correlational analyses revealed significant positive relationships between the Stress Mastery and Positive Affect components of resilience and academic performance, a significant negative relationship between the Positive Affect component of resilience and turnover intentions, as well as significant positive relationships between brain-body optimisation and all three components of resilience (Stress Mastery, Positive Affect, and Early-Life Stability). Through regression analyses, we identified the behavioural predictors that underlie resilience and outline a framework for implementing behavioural interventions to enhance resilience and increase student success. Resilience is an important non-cognitive determinant of student success in first-year students.
Protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and associated clinical sequelae requires well-coordinated metabolic and immune responses that limit viral spread and promote recovery of damaged systems. However, the role of the gut microbiota in regulating these responses has not been thoroughly investigated. In order to identify mechanisms underpinning microbiota interactions with host immune and metabolic systems that influence coronavirus disease 2019 (COVID-19) outcomes, we performed a multi-omics analysis on hospitalized COVID-19 patients and compared those with the most severe outcome (i.e. death, n = 41) to those with severe non-fatal disease (n = 89), or mild/moderate disease (n = 42), that recovered. A distinct subset of 8 cytokines (e.g. TSLP) and 140 metabolites (e.g. quinolinate) in sera identified those with a fatal outcome to infection. In addition, elevated levels of multiple pathobionts and lower levels of protective or anti-inflammatory microbes were observed in the fecal microbiome of those with the poorest clinical outcomes. Weighted gene correlation network analysis (WGCNA) identified modules that associated severity-associated cytokines with tryptophan metabolism, coagulation-linked fibrinopeptides, and bile acids with multiple pathobionts, such as Enterococcus. In contrast, less severe clinical outcomes are associated with clusters of anti-inflammatory microbes such as Bifidobacterium or Ruminococcus, short chain fatty acids (SCFAs) and IL-17A. Our study uncovered distinct mechanistic modules that link host and microbiome processes with fatal outcomes to SARS-CoV-2 infection. These features may be useful to identify at risk individuals, but also highlight a role for the microbiome in modifying hyperinflammatory responses to SARS-CoV-2 and other infectious agents.
Background: Understanding the course of post-traumatic stress disorder (PTSD) and the factors that impact this is essential to inform decisions about when and for whom screening and intervention are likely to be beneficial. Objective: To provide meta-analytic evidence of the course of recovery from PTSD in the first year following trauma, and the factors that influence that recovery. Method: We conducted a meta-analysis of observational studies of adult PTSD prevalence which included at least two assessments within the first 12 months following trauma exposure, examining prevalence statistics through to 2 years post-trauma. We examined trauma intentionality (intentional or non-intentional), PTSD assessment method (clinician or self-report), sample sex distribution, and age as moderators of PTSD prevalence over time. Results: We identified 78 eligible studies including 16,484 participants. Pooled prevalence statistics indicated that over a quarter of individuals presented with PTSD at 1 month post-trauma, with this proportion reducing by a third between 1 and 3 months. Beyond 3 months, any prevalence changes were detected over longer intervals and were small in magnitude. Intentional trauma, younger age, and female sex were associated with higher PTSD prevalence at 1 month. In addition, higher proportions of females, intentional trauma exposure, and higher baseline PTSD prevalence were each associated with larger reductions in prevalence over time. Conclusions: Recovery from PTSD following acute trauma exposure primarily occurs in the first 3 months post-trauma. Screening measures and intervention approaches offered at 3 months may better target persistent symptoms than those conducted prior to this point.
This study examines the relative effects of the different types of international financial flows on economic performance in Kenya both in the long- and short-runs using the autoregressive distributed lag model (ARDL) bounds approach and data for the period 1970 to 2017. This is against the backdrop of the government of Kenya which has targeted attracting foreign capital inflows as one of the key measures to achieving the economic pillar of the Kenya Vision 2030. The aim is to achieve an economic growth rate of 10 per cent annually and sustaining the same until 2030. After a very rigorous and careful model selection exercise, the results robustly reveal a very strong long-run causality running solely from portfolio equity to economic growth with a positive and significant effect on economic growth. In the short-run, the effect of portfolio equity on economic growth is also very positively strong. In contrast, all the other capital flows have very weak long-run relationship with economic growth with causality running only from economic growth to the capital flows. © 2022 The Author(s). This open access article is distributed under a Creative Commons Attribution (CC-BY) 4.0 license.
Background: Parenting was severely affected by lockdown, school closure, illness, movement restrictions and the many sudden changes wrought by the global emergence of COVID-19. Responding to the need for a rapid emergency response to support parents and caregivers, a consortium of providers developed a suite of COVID-19 parenting resources based on evidence-based parenting interventions. Launched in March 2020, these were adapted for online use, with versions in over 100 languages, and the possibility for downloading, radio, and oral provision. A rapid qualitative evaluation initiative was conducted from September 2020 to February 2021 to inform the procedure, understand the impact and to drive future provision. Methods: The evaluation collected openended responses surveys (n = 495 participants) and in-depth interviews with parents, providers, and adolescent children (n = 22) from 14 countries and one global source. Data were gathered on parenting challenges during COVID-19 and the utility of the COVID-19 parenting resources. In-depth, semi-structured interviews explored the same concepts and elaborated on challenges, utility of the resources, and recommendations for the future. Data were coded in a hierarchy from basic, organising and global theme generation.Results: The parenting resources equipped parents with information and practices transforming everyday lives, and interactions. The tips provided prompts and permissions related to children's behaviour, enabled communications, and offered ways to reduce stress, monitor behaviour and navigate discipline challenges. The timeliness of the resources as well as the clarity and ease of use were seen as advantages. Future direction and possible hurdles related to adaptations needed according to recipient, child age, local context, culture, and new challenges. Conclusions: Overall findings point to the value and utility of this unprecedented global response to theCOVID-19 pandemic. Results suggest that rapid provision of parenting resources at scale is feasible and of use and opens a pathway for providing evidence-based interventions under COVID-19 constraints.
Social-ecological systems (SES) research has emerged as an important area of sustainability science, informing and supporting pressing issues of transformation towards more sustainable, just and equitable futures. To date, much SES research has been done in or from the Global North, where the challenges and contexts for supporting sustainability transformations are substantially different from the Global South. This paper synthesises emerging insights on SES dynamics that can inform actions and advance research to support sustainability transformations specifically in the southern African context. The paper draws on work linked to members of the Southern African Program on Ecosystem Change and Society (SAPECS), a leading SES research network in the region, synthesizing key insights with respect to the five core themes of SAPECS: (i) transdisciplinary and engaged research, (ii) ecosystem services and human well-being, (iii) governance institutions and management practices, (iv) spatial relationships and cross-scale connections, and (v) regime shifts, traps and transformations. For each theme, we focus on insights that are particularly novel, interesting or important in the southern African context, and reflect on key research gaps and emerging frontiers for SES research in the region going forward. Such place-based insights are important for understanding the variation in SES dynamics around the world, and are crucial for informing a context-sensitive global agenda to foster sustainability transformations at local to global scales.
Deep learning is a powerful tool, which is becoming increasingly popular in financial modeling. However, model validation requirements such as SR 11-7 pose a significant obstacle to the deployment of neural networks in a bank’s production system. Their typically high number of (hyper-)parameters poses a particular challenge to model selection, benchmarking and documentation. We present a simple grid based method together with an open source implementation and show how this pragmatically satisfies model validation requirements. We illustrate the method by learning the option pricing formula in the Black–Scholes and the Heston model.
Rationale: Early surgery is recommended for hip fractures. Main result: In this study only one-third of subjects with hip fractures were admitted within 24 h of the fracture, and surgery was delayed beyond 48 h in the majority. Significance: These findings highlight the need to improve access to care for hip fracture subjects. Purpose: There is limited data on the timing of admission and surgery following a low trauma hip fracture (HF) in South Africa (SA). Methods: A prospective, observational study was conducted at public and private hospitals in three provinces, Gauteng (GP), KwaZulu-Natal (KZN) and the Western Cape (WC), in SA to determine time from fracture to admission and from admission to surgery in patients presenting with low trauma HF. Associations with delayed admission and surgery were explored using logistic regression. Results: The median age of the 1996 subjects was 73 years (IQR 63-81 years), the majority were women (1346, 67%) and 1347 (67%) were admitted to the public hospitals. In one-third of subjects (661, 33%), admission was delayed to beyond 24 h after the fracture. There was a significantly longer time to admission in public compared to private hospitals (21 h [IQR 10.0-48.5] versus 6 h [IQR 3.3-14.1], p < 0.001), in subjects < 65 years, the WC and when admission occurred on a weekday. Surgery was delayed beyond 48 h in the majority (1272, 69%) of subjects and was significantly longer in public compared to private hospitals (130 h [IQR 62.6-212.4] versus 45.4 h [IQR 24.0-75.5], p < 0.001), in KZN, and when admission occurred after hours. Conclusion: The burden of HFs is higher at public hospitals in SA, where there is a significant delay in admission after a fracture and surgery after admission. This highlights the need for a review of HF care pathways, resources and policies.
Background Motor vehicle collisions are a common cause of death and serious injury. Many casualties will remain in their vehicle following a collision. Trapped patients have more injuries and are more likely to die than their untrapped counterparts. Current extrication methods are time consuming and have a focus on movement minimisation and mitigation. The optimal extrication strategy and the effect this extrication method has on spinal movement is unknown. The aim of this study was to evaluate the movement at the cervical and lumbar spine for four commonly utilised extrication techniques. Methods Biomechanical data was collected using inertial Measurement Units on 6 healthy volunteers. The extrication types examined were: roof removal, b-post rip, rapid removal and self-extrication. Measurements were recorded at the cervical and lumbar spine, and in the anteroposterior (AP) and lateral (LAT) planes. Total movement (travel), maximal movement, mean, standard deviation and confidence intervals are reported for each extrication type. Results Data from a total of 230 extrications were collected for analysis. The smallest maximal and total movement (travel) were seen when the volunteer self-extricated (AP max = 2.6 mm, travel 4.9 mm). The largest maximal movement and travel were seen in rapid extrication extricated (AP max = 6.21 mm, travel 20.51 mm). The differences between self-extrication and all other methods were significant ( p < 0.001), small non-significant differences existed between roof removal, b-post rip and rapid removal. Self-extrication was significantly quicker than the other extrication methods (mean 6.4 s). Conclusions In healthy volunteers, self-extrication is associated with the smallest spinal movement and the fastest time to complete extrication. Rapid, B-post rip and roof off extrication types are all associated with similar movements and time to extrication in prepared vehicles.
Background Motor vehicle collisions remain a common cause of spinal cord injury. Biomechanical studies of spinal movement often lack “real world” context and applicability. Additional data may enhance our understanding of the potential for secondary spinal cord injury. We propose the metric ‘travel’ (total movement) and suggest that our understanding of movement related risk of injury could be improved if travel was routinely reported. We report maximal movement and travel for collar application in vehicle and subsequent self-extrication. Methods Biomechanical data on application of cervical collar with the volunteer sat in a vehicle were collected using Inertial Measurement Units on 6 healthy volunteers. Maximal movement and travel are reported. These data and a re-analysis of previously published work is used to demonstrate the utility of travel and maximal movement in the context of self-extrication. Results Data from a total of 60 in-vehicle collar applications across three female and three male volunteers was successfully collected for analysis. The mean age across participants was 50.3 years (range 28–68) and the BMI was 27.7 (range 21.5–34.6). The mean maximal anterior–posterior movement associated with collar application was 2.3 mm with a total AP travel of 4.9 mm. Travel (total movement) for in-car application of collar and self-extrication was 9.5 mm compared to 9.4 mm travel for self-extrication without a collar. Conclusion We have demonstrated the application of ‘travel’ in the context of self-extrication. Total travel is similar across self-extricating healthy volunteers with and without a collar. We suggest that where possible ‘travel’ is collected and reported in future biomechanical studies in this and related areas of research. It remains appropriate to apply a cervical collar to self-extricating casualties when the clinical target is that of movement minimisation.
Unconventional oil and gas (UOG) extraction can augment energy supplies in countries with viable gas resources, but it risks damaging water resources. Water supply problems for fracking can also limit UOG extraction, especially in water-stressed regions. Regulations are one of the main tools used to minimize UOG extraction impacts on water resources. Many states in the US and Canada have extensive regulations to protect water resources during UOG extraction but they are often ineffective, either because they were poorly drafted or because they are not properly enforced. South Africa is a water-scarce, groundwater-dependent country that is considering UOG extraction in the future. South African groundwater experts were surveyed on what regulations are needed to protect groundwater resources and how to enforce them. This study recommends specific UOG extraction regulations to protect groundwater resources, which are not only relevant to South Africa, but also to other countries that extract UOG resources.
Background Collisions in rugby union and sevens have a high injury incidence and burden, and are also associated with player and team performance. Understanding the frequency and intensity of these collisions is therefore important for coaches and practitioners to adequately prepare players for competition. The aim of this review is to synthesise the current literature to provide a summary of the collision frequencies and intensities for rugby union and rugby sevens based on video-based analysis and microtechnology. Methods A systematic search using key words was done on four different databases from 1 January 1990 to 1 September 2021 (PubMed, Scopus, SPORTDiscus and Web of Science). Results Seventy-three studies were included in the final review, with fifty-eight studies focusing on rugby union, while fifteen studies explored rugby sevens. Of the included studies, four focused on training—three in rugby union and one in sevens, two focused on both training and match-play in rugby union and one in rugby sevens, while the remaining sixty-six studies explored collisions from match-play. The studies included, provincial, national, international, professional, experienced, novice and collegiate players. Most of the studies used video-based analysis (n = 37) to quantify collisions. In rugby union, on average a total of 22.0 (19.0–25.0) scrums, 116.2 (62.7–169.7) rucks, and 156.1 (121.2–191.0) tackles occur per match. In sevens, on average 1.8 (1.7–2.0) scrums, 4.8 (0–11.8) rucks and 14.1 (0–32.8) tackles occur per match. Conclusions This review showed more studies quantified collisions in matches compared to training. To ensure athletes are adequately prepared for match collision loads, training should be prescribed to meet the match demands. Per minute, rugby sevens players perform more tackles and ball carries into contact than rugby union players and forwards experienced more impacts and tackles than backs. Forwards also perform more very heavy impacts and severe impacts than backs in rugby union. To improve the relationship between matches and training, integrating both video-based analysis and microtechnology is recommended. The frequency and intensity of collisions in training and matches may lead to adaptations for a “collision-fit” player and lend itself to general training principles such as periodisation for optimum collision adaptation. Trial Registration PROSPERO registration number: CRD42020191112.
The accurate simulation of additional interactions at the ATLAS experiment for the analysis of proton–proton collisions delivered by the Large Hadron Collider presents a significant challenge to the computing resources. During the LHC Run 2 (2015–2018), there were up to 70 inelastic interactions per bunch crossing, which need to be accounted for in Monte Carlo (MC) production. In this document, a new method to account for these additional interactions in the simulation chain is described. Instead of sampling the inelastic interactions and adding their energy deposits to a hard-scatter interaction one-by-one, the inelastic interactions are presampled, independent of the hard scatter, and stored as combined events. Consequently, for each hard-scatter interaction, only one such presampled event needs to be added as part of the simulation chain. For the Run 2 simulation chain, with an average of 35 interactions per bunch crossing, this new method provides a substantial reduction in MC production CPU needs of around 20%, while reproducing the properties of the reconstructed quantities relevant for physics analyses with good accuracy.
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19,269 members
Mattia Vaccari
  • Department of Astronomy
Hanna-Andrea Rother
  • Environmental Health Division
Muki Shey
  • Department of Medicine
7700, Cape Town, South Africa