The do’s and don’ts of arginine supplementation

In the last three decades the nutritional and pharmacologic effects of arginine have been the subject of intense investigation. Taking into consideration the many benefits that have been demonstrated from arginine supplementation, the question remains: “Can we afford not to supplement with this immuno-nutrient”. The potential life-saving cardiovascular effects of arginine in both acute and chronic arginine supplementation has the ability to revolutionise the management of vascular disease, yet much more research must be done in this area. In addition, the proposed benefits of such supplementation in the sepsis model, makes arginine a very attractive model for decreasing the mortality statistics of this worldwide disease process. However, owing to the fact that arginine is a precursor for nitric oxide synthesis, the effects of which are potentially detrimental in the septic patient, further research is warranted in this field to determine the suitability of this agent in patient management

Does Indivisible Labor Explain the Difference Between Micro and Macro Elasticities? A Meta-Analysis of Extensive Margin Elasticities

Macroeconomic calibrations imply much larger labor supply elasticities than microeconometric studies. One prominent explanation for this divergence is that indivisible labor generates extensive margin responses that are not captured in micro studies of hours choices. We evaluate whether existing calibrations of macro models are consistent with micro evidence on extensive margin responses using two approaches. First, we use a standard calibrated macro model to simulate the impacts of tax policy changes on labor supply. Second, we present a meta-analysis of quasi-experimental estimates of extensive margin elasticities. We find that micro estimates are consistent with macro evidence on the steady-state (Hicksian) elasticities relevant for cross-country comparisons. However, micro estimates of extensive-margin elasticities are an order of magnitude smaller than the values needed to explain business cycle fluctuations in aggregate hours. Hence, indivisible labor supply does not explain the large gap between micro and macro estimates of intertemporal substitution (Frisch) elasticities. Our synthesis of the micro evidence points to Hicksian elasticities of 0.3 on the intensive and 0.25 on the extensive margin and Frisch elasticities of 0.5 on the intensive and 0.25 on the extensive margin.

Gold mining’s toxic legacy: Pollutant transport and accumulation in the Klip River catchment, Johannesburg

Waste from gold mines is considered to constitute the largest single source of waste pollution in South Africa and contributes significantly to acid mine drainage, which remains one of the country’s most serious environmental and socio-economic issues. Run-off from the Central Rand Goldfield discharges into wetlands along the Klip River, which are known to be important sinks for toxic pollutants. The aim of this study was to examine the transport, migration and sequestration of metal pollutants in the upper Klip River catchment in further detail. Analyses reveal that the majority of pollutants are associated with contaminant plumes that emanate from mine dumps and enter the wetland via groundwater recharge. This water carries highly elevated concentrations of Co, Ni, Zn, U and rare earth elements, which are naturally sequestered within the wetland, largely through precipitation and adsorption. While surface runoff from mine dumps severely contaminates watercourses within the upper catchment, surface inputs are considered relatively minor contributors to the overall pollutant load entering the Klip River wetland, although aerosol fallout is an important source of Pb. The extensive accumulation of metals within the Klip River wetland reflects the contaminant legacy associated with gold mining on the Witwatersrand and highlights the vital role this natural system has played in trapping vast quantities of toxic pollutants and remediating downstream waters. Contaminant plumes associated with mine dumps will likely persist for decades; preventing further deterioration of the Klip River wetlands is thus critical for safeguarding water sources in the region.  Significance:  Run-off and groundwater emanating from the Central Witwatersrand Basin is highly contaminated with toxic metals. The seepage of acidic water from mine waste dumps is considered the primary source of contamination. Significant quantities of pollutants are trapped naturally within the Klip River wetland. Preventing further deterioration of the Klip River wetlands is critical for the protection of freshwater resources in the region

Physiotherapists’ perception of a community-based primary healthcare clinical education approach to undergraduate learning

Background. South African health systems are challenged by numerous stressors, such as a lack of resources, staff shortages and overburdened public sector demands. This necessitates appropriately equipped and trained healthcare professionals to meet the demands of this system. Community-based primary healthcare (PHC) clinical education is an approach towards preparing health science students to meet these demands. Clinical education is the cornerstone of undergraduate training. Physiotherapists are among the healthcare professionals who require undergraduate training that drives competence for independent practice.Objective. To explore the perceptions and experiences of physiotherapists as clinical supervisors within a physiotherapy undergraduate programme that adopted a community-based PHC approach to clinical training.Methods. An explorative qualitative approach was used, with semi-structured interviews with 10 purposively selected physiotherapists supervising students on the newly introduced platform. Data were transcribed and analysed using content analysis.Results. Seven themes emerged from the data, which relate to curriculum redress, organisational factors, stakeholder dynamics, barriers and enablers to decentralised clinical training, perceived preparedness for practice and recommendations.Conclusions. As the need for an increasing number of health professionals is realised, more innovative methods for clinical education of undergraduate health science students are required. Community-based PHC training for physiotherapy students is one such approach and was generally perceived as a valuable framework to incorporate competencies required for practice as future independent practitioners. Furthermore, improved communication between students, clinicians and academic staff was seen as a recommendation to influence clinical education

Critical transformation in higher education: Ethical reflections on #

Protest movements such as the #MustFall currently dominate the South African higher education landscape. This article focuses on such protest movements, paying particular attention to protests against gender-based violations at some universities, commonly referred to as #RapeMustFall, as an exemplar of the gender injustices and inequities that persist. We argue that debates and policies about gender-based violations at universities cannot and should not be overshadowed by deficient grand narratives informed by patriarchy, colonialism and capitalism. To frame this argument, we critically review the current status quo from a gender mainstreaming policy-making perspective. We then argue the merits of an ethical perspective to transformation in higher education. Critical transformation in higher education requires not only epistemological change and access, but should be a fundamentally ethical pursuit

Estimating total evaporation at the field scale using the SEBS model and data infilling procedures

The spatial representativeness of total evaporation estimates (ET) acquired from conventional approaches is limited, as these techniques generally provide site-specific values. The use of satellite earth observation has shown a great deal of potential in capturing spatially representative hydro-meteorological flux data and therefore represents a practical alternative for estimating ET. However, one of the challenges facing ET estimation using satellite earth observation data is the effect of clouds, which reduce the number of satellite images available for use. The objectives of this paper were firstly to validate satellite-derived ET estimates against estimates acquired from a surface renewal system and, secondly, to assess the feasibility of two infilling techniques to create a daily satellite-derived ET time series. The Surface Energy Balance System (SEBS) model was used to derive daily ET using MODIS imagery. Two infilling approaches, the Kcact approach and a linear interpolation approach, were evaluated by comparing their respective values against in-situ ET measurements, as well as SEBS ET estimates derived using MODIS. The results showed that SEBS ET estimates were approximately 47% higher and produced R2 and RMSE values of 0.33 and 2.19 mm∙d-1, respectively, compared to in-situ ET values. The ET estimates obtained by applying the Kcact approach and the linear interpolation approach compared favourably with the in-situ ET values, producing RMSE values of 0.9 mm∙d-1 and 0.6 mm∙d-1, respectively. However, comparisons of ET estimates acquired by applying the Kcact approach and the linear interpolation approach against the SEBS ET indicated a poor match, yielding RMSE values of 1.96 mm∙d-1 and 1.54 mm∙d-1, respectively.Keywords: satellite earth observation, SEBS Model, ET, infilling, surface renewal syste

Unrecognised postoperative residual curarisation in developing countries remains a common problem

Background. Postoperative residual curarisation (PORC) is a potentially life-threatening complication of non-depolarising muscle relaxant use in anaesthesia. Quantitative neuromuscular monitoring has the potential to reduce the risk of PORC, but many anaesthetists rely on clinical assessment of neuromuscular function alone.Objectives. To investigate the occurrence of PORC in the recovery room at an academic hospital in Gauteng, South Africa. Additionally, this prospective, cross-sectional study aimed to determine the extent of intraoperative neuromuscular monitoring and to assess clinical factors that may influence the risk of PORC.Methods. Patient characteristics and clinical information, including whether neuromuscular monitoring had been conducted, were recorded. Patients were evaluated by clinical assessment and determination of a quantitative train-of-four ratio (TOFR). PORC assessment methods were compared and clinical characteristics were analysed for association with TOFR status.Results. The incidence of PORC (TOFR <0.9) in the study group was 45.5%; however, 78% passed the clinical assessment. The specificity of clinical assessment to detect residual paralysis was 24%. Notably, only 3 patients (6%) were monitored intraoperatively for neuromuscular function. Advanced age (p=0.011, r=–0.34) and female gender (p=0.001) were shown to be associated with a TOFR <0.7.Conclusions. PORC is more common in practice than currently recognised. This deduction is supported by the low rate of intraoperative neuromuscular monitoring conducted and the high pass rate on clinical assessment. Routine use of quantitative monitoring of neuromuscular function should be encouraged to minimise the risk of this serious yet preventable condition

Unusual urological presentations of HIV/AIDS at King Edward VIII Hospital

No Abstract