Throughput Analysis of an Adaptation Rule in the HARQ Environment

In this paper we analyze the adaptation rule, which estimates the channel state and switches between hybrid ARQ (automatic-repeat-request) and pure ARQ. Convolutional code was chosen as FEC (forward-error-correction) in hybrid ARQ part and go-back-N ARQ scheme is used in both cases. The adaptation rule is based on counting ACKs and NAKs and its throughput analysis is made

The complexity of neuropsychiatric manifestations of COVID-19 in South Africa

SARS-CoV-2 was first identified in Wuhan City, China, in 2019. Initially it was associated with the development of pulmonary disease, but research over the past 2 years has identified effects on multiple systems. Neuropsychiatric manifestations of COVID-19 have been reported in countries around the world, including new-onset psychosis in patients with no personal or family psychiatric history. We present the first case series describing neuropsychiatric manifestations of patients in Johannesburg, South Africa (SA). All four patients presented with their index-episode psychosis, and evidence of COVID-19 infection. The patients had varied psychiatric presentations, from delirium and psychosis to mania, and all responded well to low doses of antipsychotics. One patient had newly diagnosed HIV in addition to COVID-19. Further research is needed to determine the prevalence of neuropsychiatric manifestations in acute SARS-CoV-2 infections in SA

What Do Fact Checkers Fact-check When?

Recent research suggests that not all fact checking efforts are equal: when and what is fact checked plays a pivotal role in effectively correcting misconceptions. In this paper, we propose a framework to study fact checking efforts using Google Trends, a signal that captures search interest over topics on the world's largest search engine. Our framework consists of extracting claims from fact checking efforts, linking such claims with knowledge graph entities, and estimating the online attention they receive. We use this framework to study a dataset of 879 COVID-19-related fact checks done in 2020 by 81 international organizations. Our findings suggest that there is often a disconnect between online attention and fact checking efforts. For example, in around 40% of countries where 10 or more claims were fact checked, half or more than half of the top 10 most popular claims were not fact checked. Our analysis also shows that claims are first fact checked after receiving, on average, 35% of the total online attention they would eventually receive in 2020. Yet, there is a big variation among claims: some were fact checked before receiving a surge of misinformation-induced online attention, others are fact checked much later. Overall, our work suggests that the incorporation of online attention signals may help organizations better assess and prioritize their fact checking efforts. Also, in the context of international collaboration, where claims are fact checked multiple times across different countries, online attention could help organizations keep track of which claims are "migrating" between different countries

Randomised trials of COVID-19 vaccines in Africa – charting the path forward.

Vaccines have played a critical role in controlling disease outbreaks, hence the proliferation of the development and testing of multiple vaccine candidates during the COVID-19 pandemic. Randomised trials are gold standards for evaluating the safety and efficacy of pharmaceutical interventions such as COVID-19 vaccines. However, contextual differences may attenuate effects of COVID-19 vaccines. Thus, the need to conduct COVID-19 vaccine trials in all settings, including in Africa. We conducted a crosssectional analysis of planned, ongoing, and completed COVID-19 vaccine trials in Africa. We searched the South African National Clinical Trials Register, Pan African Clinical Trials Registry, and International Clinical Trials Registry Platform (ICTRP) on 12 January and 30 April 2022; and complemented this with a search of ClinicalTrials.gov on 17 May 2022. We screened the search output and included randomised trials with at least one recruitment site in Africa. We identified only 108 eligible trials: 90 (83%) evaluating candidate COVID-19 vaccines, 11 (10%) assessing if existing vaccines could prevent SARS-CoV-2 infection, and 7 (7%) evaluating interventions for improving COVID-19 vaccination coverage. South Africa had the highest number of trials at 58 (54%). Beyond South Africa, countries with more than 10 trial sites include Kenya, Ghana, Egypt, Uganda, and Zimbabwe. Among the trials, 14 (13%) do not have principal investigators based in Africa, 39 (30%) are funded by industry, and 91 (84%) are funded by institutions based outside the host country. COVID-19 vaccine trials with recruitment sites in Africa represented only 7% of the 1453 COVID-19 vaccine trials in the ICTRP. The paucity of COVID-19 vaccine trials conducted on the African continent is a cause for concern. This has implications for the role that Africa may play in future pandemics.Significance:• There are generally very few vaccine trials conducted in Africa, relative to the rest of the world.• The limited vaccine trials in Africa could be attributed to limited expertise and resources, both human and material, as well as lack of perceived market.• It is reassuring that many COVID-19 vaccines are planned, being conducted, or have been conducted in multiple African countries; but there is a need for more African public sector funding for vaccine trials on the continent

Detection of tet(M) gene from raw milk by rapid DNA extraction followed by a two-step PCR with nested primers.

The likelihood that milk and milk products may act as a vehicle for antibiotic-resistant bacterial genes has become a concern to the food industry and a public health issue, and the demand for rapid tests has increased. The purity of DNA extracted from food samples is a key issue in the sensitivity and usefulness of biological analyses, such as PCR for pathogens and nonpathogens. A rapid, phenol-chloroform free method based on a modification of a sodium iodide DNA extraction, followed by a two-step PCR was developed for direct detection of the tet(M) gene in milk samples within a single working day. This study compares the proposed method with a traditional phenol solvent extraction method and with a commercial kit (QIAamp DNA blood mini kit, Qiagen). The three DNA extraction methods were used to ensure access to the tet(M) gene from 1 ml of raw milk, inoculated with a strain of Enterococcus faecalis, which carries the tet(M) gene. The proposed method, followed by a two-step PCR with nested primers specific for the tet(M) gene, was able to reach a detection limit below 10 CFU/ml in less than 4 h, including the two amplification cycles, thus outperforming in sensitivity and rapidity both the traditional and the commercial method

Moving towards universal health coverage: Strengthening the evidence ecosystem for the South African health system

Health policy and systems research (HPSR) guides health system reforms and is essential for South Africa (SA)’s progress towards universal coverage of high-quality healthcare. For HPSR evidence to inform and strengthen health systems, it needs to flow efficiently between evidence producers, evidence synthesisers, evidence processers and disseminators and evidence implementors in an evidence ecosystem. A substantial body of evidence for health systems strengthening is generated in SA, and this informs national and international health system guidelines and guidance. In this manuscript, in celebration of the 50th anniversary of the SA Medical Research Council, we apply an evidence ecosystem lens to the SA health system, and discuss its current functioning in support of the achievement of a high-quality health system that is able to achieve universal health coverage. We use three case studies to describe successes, challenges and gaps in the functioning of the evidence ecosystem. The first case study focuses on using evidence to strengthen health-system governance and support for community health worker programmes. The second case focuses on managing the growing epidemic of drug-resistant tuberculosis, while the third case focuses on social protection, the child support grant and its impact on health. SA scientists are part of global initiatives to strengthen the health-systems evidence ecosystem, specifically through pioneering methods to synthesise evidence and produce evidence-informed guidelines to facilitate evidence use in health-system decision-making. SA institutes of health policy analysis facilitate involvement of evidence producers and synthesisers in the national health system policy-making process. A future priority is to further strengthen national initiatives to translate evidence into policy and practice and to sustain capacity for continuous technical support to health-systems policy development and implementation

Enterotoxin production by Staphylococcus aureus isolated from mastitic cows.

Staphylococcus aureus is an important cause of mastitis in cows. The ability of S. aureus strains to produce one or more enterotoxins in milk and dairy products is linked to staphylococcal food poisoning. To determine whether staphylococci causing bovine mastitis could cause human foodborne intoxication, the production of staphylococcal enterotoxins A through D (SEA, SEB, SEC, and SED) by 160 S. aureus isolates was evaluated with the use of a reverse passive latex agglutination enterotoxin kit. All S. aureus strains were isolated over a 9-month period from 2,343 routine submissions of a composite quarter collection of individual mastitic cows at 18 dairy farms in the San Joaquin Valley in California. Prior to enterotoxin detection, isolates were grown by a method that enhances the in vitro synthesis of enterotoxin. Twenty-two of 160 S. aureus isolates produced enterotoxin. Seven produced SEC, 12 produced SED, and 3 produced both SEC and SED. None of the isolates produced SEA or SEB

Thalassaemia (part 2): Management

The management of thalassaemia with a severe phenotype includes blood transfusion, iron chelation, bone marrow transplantation, prenatal diagnosis and national programmes to co-ordinate these in countries with a high prevalence. If blood transfusion and iron chelation therapy are not administered regularly, as was the case historically and as is still the case in many poorer regions, progressive deterioration occurs, viz. impaired growth and development, hepatosplenomegaly, bony abnormalities, cardiac failure, increased susceptibility to infections and premature mortality. Remarkable progress has been made in the past few decades, which has led to much-improved survival rates. Transfusion therapy has evolved to a hyper-transfusion regimen designed to maintain a physiological haemoglobin level and achieve a post-transfusion haemoglobin of 14 g/dL, which, as a matter of course, necessitated intensification of iron chelation. The development of effective oral iron chelators has led to improved compliance. Exploration of novel therapeutic approaches continues, with several agents under study. The prospect of gene therapy is particularly exciting as it has potential to provide cure on a large scale. Currently, regular blood transfusion and iron chelation therapy remain the cornerstone of management of thalassaemia major