A restricted composite likelihood approach to modelling Gaussian geostatistical data

Composite likelihood methods have become popular in spatial statistics. This is mainly due to the fact that large matrices need to be inverted in full maximum likelihood and this becomes computationally expensive when you have a large number of regions under consideration. We introduce restricted pairwise composite likelihood (RECL) methods for estimation of mean and covariance parameters in a Gaussian random field, without resorting back to the full likelihood. A simulation study is carried out to investigate how this method works in settings of increasing domain as well as in-fill asymptotics, whilst varying the strength of correlation. Preliminary results showed that pairwise composite likelihoods tend to underestimate the variance parameters, especially when there is high correlation, while RECL corrects for the underestimation. Therefore, RECL is recommended if interest is in both the mean and the variance parameters

Production of enzymes for industrial wastewater treatment – Proof of concept and application to the textile dye industry

A previous Water Research Commission Project (WRC Report No: 1170/1/04) into the enzymology of solubilisation of municipal sewage sludge (Rhodes University BioSURE Process®) identified the involvement of a plethora of hydrolase enzymes such as phosphatases. sulphatases. proteases. Upases, endoglucanascs and glucosidases (Pletschke et al., 2004; Whiteley et al.. 2002; Enongene. et al. 2003; Ngesi. et al. 2002) isolated from a biosuiphidogenic reactor. Furthermore it was found that these enzymes could be used, in situ, to bioremediate effluents from acid mine drainage, tanneries and abattoirs. It is the intention of the current research to exploit this idea further and undertake a thorough investigation to show that hydrogenase enzymes, also found within the biosuiphidogenic reactor, could be used to bioremediate industrial waste effluent from the textile dye industry. Azo dyes are the most commonly used colouring compounds (Pearce et al.. 2003) and they were therefore used in this study to investigate the ability of sulphate reducing bacteria (SRB) and associated cytoplasmic hydrogenase enzymes to degrade them under anaerobic conditions. Several advantages of using such a system are forthcomin

Slow acceptance of universal antiretroviral therapy (ART) among mothers enrolled in IMPAACT PROMISE studies across the globe

CITATION: Stranix‑Chibanda, L., et al. 2019. Slow acceptance of universal antiretroviral therapy (ART) among mothers enrolled in IMPAACT PROMISE studies across the globe. AIDS and Behavior, 23:2522-2531, doi:10.1007/s10461-019-02624-3.The original publication is available at https://link.springer.comThe PROMISE trial enrolled asymptomatic HIV-infected pregnant and postpartum women not eligible for antiretroviral treatment (ART) per local guidelines and randomly assigned proven antiretroviral strategies to assess relative efficacy for perinatal prevention plus maternal/infant safety and maternal health. The START study subsequently demonstrated clear benefit in initiating ART regardless of CD4 count. Active PROMISE participants were informed of results and women not receiving ART were strongly recommended to immediately initiate treatment to optimize their own health. We recorded their decision and the primary reason given for accepting or rejecting the universal ART offer after receiving the START information. One-third of participants did not initiate ART after the initial session, wanting more time to consider. Six sessions were required to attain 95% uptake. The slow uptake of universal ART highlights the need to prepare individuals and sensitize communities regarding the personal and population benefits of the “Treat All” strategy.https://link.springer.com/article/10.1007/s10461-019-02624-3Publisher's versio

Enhanced infection prophylaxis reduces mortality in severely immunosuppressed HIV-infected adults and older children initiating antiretroviral therapy in Kenya, Malawi, Uganda and Zimbabwe: the REALITY trial

Meeting abstract FRAB0101LB from 21st International AIDS Conference 18–22 July 2016, Durban, South Africa. Introduction: Mortality from infections is high in the first 6 months of antiretroviral therapy (ART) among HIV‐infected adults and children with advanced disease in sub‐Saharan Africa. Whether an enhanced package of infection prophylaxis at ART initiation would reduce mortality is unknown. Methods: The REALITY 2×2×2 factorial open‐label trial (ISRCTN43622374) randomized ART‐naïve HIV‐infected adults and children >5 years with CD4 <100 cells/mm3. This randomization compared initiating ART with enhanced prophylaxis (continuous cotrimoxazole plus 12 weeks isoniazid/pyridoxine (anti‐tuberculosis) and fluconazole (anti‐cryptococcal/candida), 5 days azithromycin (anti‐bacterial/protozoal) and single‐dose albendazole (anti‐helminth)), versus standard‐of‐care cotrimoxazole. Isoniazid/pyridoxine/cotrimoxazole was formulated as a scored fixed‐dose combination. Two other randomizations investigated 12‐week adjunctive raltegravir or supplementary food. The primary endpoint was 24‐week mortality. Results: 1805 eligible adults (n = 1733; 96.0%) and children/adolescents (n = 72; 4.0%) (median 36 years; 53.2% male) were randomized to enhanced (n = 906) or standard prophylaxis (n = 899) and followed for 48 weeks (3.8% loss‐to‐follow‐up). Median baseline CD4 was 36 cells/mm3 (IQR: 16–62) but 47.3% were WHO Stage 1/2. 80 (8.9%) enhanced versus 108(12.2%) standard prophylaxis died before 24 weeks (adjusted hazard ratio (aHR) = 0.73 (95% CI: 0.54–0.97) p = 0.03; Figure 1) and 98(11.0%) versus 127(14.4%) respectively died before 48 weeks (aHR = 0.75 (0.58–0.98) p = 0.04), with no evidence of interaction with the two other randomizations (p > 0.8). Enhanced prophylaxis significantly reduced incidence of tuberculosis (p = 0.02), cryptococcal disease (p = 0.01), oral/oesophageal candidiasis (p = 0.02), deaths of unknown cause (p = 0.02) and (marginally) hospitalisations (p = 0.06) but not presumed severe bacterial infections (p = 0.38). Serious and grade 4 adverse events were marginally less common with enhanced prophylaxis (p = 0.06). CD4 increases and VL suppression were similar between groups (p > 0.2). Conclusions: Enhanced infection prophylaxis at ART initiation reduces early mortality by 25% among HIV‐infected adults and children with advanced disease. The pill burden did not adversely affect VL suppression. Policy makers should consider adopting and implementing this low‐cost broad infection prevention package which could save 3.3 lives for every 100 individuals treated

BJS commission on surgery and perioperative care post-COVID-19

Background: Coronavirus disease 2019 (COVID-19) was declared a pandemic by the WHO on 11 March 2020 and global surgical practice was compromised. This Commission aimed to document and reflect on the changes seen in the surgical environment during the pandemic, by reviewing colleagues experiences and published evidence. Methods: In late 2020, BJS contacted colleagues across the global surgical community and asked them to describe how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had affected their practice. In addition to this, the Commission undertook a literature review on the impact of COVID-19 on surgery and perioperative care. A thematic analysis was performed to identify the issues most frequently encountered by the correspondents, as well as the solutions and ideas suggested to address them. Results: BJS received communications for this Commission from leading clinicians and academics across a variety of surgical specialties in every inhabited continent. The responses from all over the world provided insights into multiple facets of surgical practice from a governmental level to individual clinical practice and training. Conclusion: The COVID-19 pandemic has uncovered a variety of problems in healthcare systems, including negative impacts on surgical practice. Global surgical multidisciplinary teams are working collaboratively to address research questions about the future of surgery in the post-COVID-19 era. The COVID-19 pandemic is severely damaging surgical training. The establishment of a multidisciplinary ethics committee should be encouraged at all surgical oncology centres. Innovative leadership and collaboration is vital in the post-COVID-19 era