Short communication: The effect of ultrasound at 256 KHz on Microcystis aeruginosa, with and without gas vacuoles

The effect of ultrasound on the growth of M. aeruginosa confirmed to contain gas vacuoles and on a laboratory culture with no gas vacuoles was investigated. Both cultures were treated continuously for 9 d with an ultrasonic flow device. To evaluate the influence of ultrasound during the treatment, the chlorophyll-a concentration was measured daily. Furthermore, changes in culture characteristics, e.g., flotation and gas vesicle formation, were determined. The results showed that, in contrast to the control, both ultrasonic-treated cultures had a lower chlorophyll-a concentration and cell aggregates were disrupted. Transmission electron microscopy confirmed a collapse of gas vacuoles in the environmental culture, while the laboratory culture, which did not contain gas vacuoles, showed many membrane-damaged cells. It was concluded that ultrasonic treatment of M. aeruginosa caused the disruption of gas vacuoles and destruction of cell membranes.Keywords: Ultrasound, cyanobacteria, Microcystis aeruginosa, chlorophyll, gas vacuole

Assessing the clogging and permeability of degrading packed bed reactors

In South Africa, the need for water treatment is increasing, especially in the mining sector. As active water treatment technologies are expensive, the mining sector has an increasing need for passive water treatment technology, with low maintenance and operating costs, yet efficient water treatment ability. Literature on passive water treatment suggests that these systems only offer a narrow range of treatment capabilities. Therefore, hybrid water treatment systems could be a solution to low-cost water treatment in South Africa. The degrading packed bed reactor (DPBR) is one of the units comprising the hybrid treatment group. The DPBR’s main action is to convert sulfates into sulfides and alkalinity, since this reduces the impact on the environment by increasing the pH and reducing the salinity. In this study, 6 small-scale DPBRs were constructed. Each was classified according to its unique organic source (manure, straw, vegetable food processing waste, wood shavings, chicken litter and a combined sample with layers of all the carbon sources). Synthetic acid mine drainage (AMD) was fed through the 6 bioreactors for a period of 3 months. Permeabilities, leachate samples and effective void volumes were measured from the DPBRs. From the experiments conducted, it was found that the manure and combination bioreactors (with equal layers of manure, straw, compost, wood shavings and chicken litter) had the lowest overall permeabilities, with straw and compost having the highest permeabilities. Linked to this, the experiments showed that the manure and combination bioreactors had the largest decreases in effective porosity with straw and compost having the least. Hydraulically, the combination bioreactor performed the best by incorporating the best attributes from each carbon source. Wood shavings preformed almost as well. Chicken litter clogged within 18 days after the initiation of the experiment and thus was the least effective substrate.Keywords: degrading packed bed reactor, cloggin

Technical note The formulation of synthetic domestic wastewater sludge medium to study anaerobic biological treatment of acid mine drainage in the laboratory

Requirements for successful biological treatment of acid mine drainage (AMD) rely on the reduction of sulphates by microorganisms using a suitable organic carbon source. Various carbon sources, such as domestic wastewater sludge, have previously been used in the semi-passive biological treatment of  AMD. Domestic wastewater sludge is however highly variable in its composition, making laboratory  experimentation difficult. Synthetic medium was therefore formulated based on the chemical oxygen demand (COD) and the biological degradable organic matter (BOD) of domestic wastewater sludge. Four synthetic media compositions were formulated consisting of different ratios of meat extract,  vegetable extract, sodium chloride, potassium phosphate, urea, ammonium chloride, iron sulphate, magnesium sulphate and glucose. The media composition with BOD and COD measurements closest to that of anaerobic domestic wastewater sludge was selected for further studies. The combination of AMD to synthetic wastewater sludge in 3 ratios was determined for COD and sulphate reduction in bioreactors over a period of 90 d. The highest reduction of 86.76% in COD and 99.22% in sulphate content were obtained in a 1:1 AMD: synthetic domestic wastewater sludge (SDWWS) ratio that calculated to a COD/sulphate ratio of 3.Keywords: acid mine drainage, synthetic domestic wastewater sludge, sulphates, CO

Functional health state description and valuation by people aged 65 and over:a pilot study

Abstract Background Assessing quality of life among the elderly is a complex and multifaceted issue. Elderly people might find valuing and describing their personal experience of quality of life (QoL) demanding and cumbersome. This study therefore sought to determine the feasibility of administering two questionnaires in two samples of elderly people. Methods A preference-based instrument (EQ-5D + C) and a currently achieved functioning questionnaire (CAF) were utilized. Two pilot studies were performed. The first was performed in South Africa (n = 30), designed to test whether elderly respondents could complete and understand the two questionnaires and also to indicate which valuation method, visual analogue scale or time trade off they preferred. A second pilot study was performed in the Netherlands (n = 30), designed to investigate the use of both questionnaires in determining quality of life and health state valuations in a Dutch sample of elderly. Results Seventy percent of the South African respondents indicated that they preferred the visual analogue scale (VAS) method, when compared to the time trade-off (TTO). In both the South African and the Dutch pilot studies, the respondents, with different dependency levels, were able to use both questionnaires to determine health state descriptions and valuations. When ranking the profiles from fewer to more problems, the EQ-5D + C exhibits a gradual downwards trend, with a maximum of 100 and minimum VAS value of 41. The CAF also exhibits a gradual downwards trend, with a maximum of 1.00 and minimum VAS value of 36. Conclusions The results indicate that individuals from different parts of the world are able to complete, describe, and value the questionnaires. It is our recommendation that a comprehensive study should be done, which includes both the EQ-5D + C questionnaire and the CAF questionnaire, since the two questionnaires have proven to be feasible in providing information on quality of life and well-being of elderly people

Exploring management perceptions of competitive versus transient advantage

Creating a Sustainable Competitive Advantage (SCA) is regarded as the central principle of strategy. Yet, scholarly and practical debates require the ability to pursue a SCA as an organisational purpose. With contemporary environmental pressures, it is uncertain whether organisations practically have the ability to succeed in creating and sustaining a Competitive Advantage (CA). On the contrary, the concept of transient advantage (TA) shows an increasing prevalence and synergy towards dynamic environments. Despite this, several organisations indicate the retention of CA as focus. This research confirms that many decision-makers fail to understand the concepts and their applicability in business. The authors of this study address the limited academic attention to the understanding, relevance and differentiation of competitive and TA at practical level. The findings of exploratory research with senior-level managers point to business executives misapprehending other terms for CA, one being TA. Transient advantage appears to be deemed more prevalent, due to contemporary environmental pressures as well as volatile regulatory requirements. The pursuance of sustainability appears problematic. The study contributes practically in that TA can be intentionally pursued through the business model flexibility to improve organisational performance.http://www.journals.co.za/content/journal/jcmanam2020Business Managemen

An inferential comparison between the capabilities and achievements of 1st-year medical and nursing students at the University of the Free State, Bloemfontein, South Africa

Background. Research indicates that academic stressors, living circumstances, working conditions and where students undertake leisure activities affectacademic performance, capabilities and achievements (functionings).Objective. To investigate how 1st-year medical and nursing students perceived their own capabilities compared with their actual achievements (functionings). The article focuses on the achievements (functionings), as these students were admitted through a selection process, indicating their potential capability to succeed.Methods. In this descriptive, comparative study, all 1st-year medical and nursing students at the University of the Free State, Bloemfontein, South Africawere invited to complete a validated questionnaire to reflect their capabilities (scope) and achievements (outcomes). The questionnaire incorporated seven domains: happiness, achievements, health, intellect, social relations, environment and integrity. Data were analysed using descriptive statistics(frequencies, medians, means, standard deviations and standard errors).Results. All respondents valued the domains positively with regard to the outcomes (functionings). On average, nursing students valued the domains17.4% lower than the medical students. Integrity was valued the highest by all. Health scored the lowest in the medical group, and environment (wherestudents study and undertake leisure activities) the lowest in the nursing group.Conclusions. Medical schools should include wellness in their curricula, limit the degree of physical and emotional exhaustion associated with training, and have realistic expectations of students. Programmes should allocate enough time for students to manage their time well to take part in physical activity and eat healthy foods. Nursing students’ work environment should improve. More time should be made available for leisure activities andimprovement to students’ study environment

The end of the line? A case of drug resistance to third-line antiretroviral therapy

HIV drug resistance has been described in all antiretroviral drug classes and threatens the long-term success of HIV treatment. Here, we describe the first reported case of acquired resistance to the integrase strand transfer inhibitors in South Africa. This case illustrates the dilemma of treatment in the context of inadequate adherence and poor psychosocial support and highlights the potential risk of transmission of multidrug-resistant virus.http://www.sajhivmed.org.zaam2016Family MedicineImmunolog