Optimising the imbaula stove

In South Africa, human and environmental health implications from domestic solid fuel combustion have spurred interest in cleaner alternative sources of energy and better combustion technologies. Field research among wood and coal burning informal settlements in Johannesburg has shown that the most prevalent mode of combustion is self-made imbaula (brazier) stoves, manufactured from discarded 20 L steel drums. Such stoves are made without any measure of performance optimisation, leading to fuel inefficiency and high emissions - previous field surveys have indicated that the number, size and placement of primary and secondary air inlets (taken as holes below and above the fire grate respectively) vary over a wide range, starting from an extreme with no holes below the grate [1]. Researchers at SeTAR Centre, University of Johannesburg, have set out to develop an enhanced imbaula, by investigating performance in terms of size and distribution of primary and secondary air inlets, and height of grate level. The test imbaulas are constructed out of standard 20 L drums with a height of 360 mm and diameter of 295 mm. A range of hole configurations has been designed, from which selected test configurations are fabricated for experimental evaluation of thermal and emissions properties, using the SeTAR heterogeneous testing protocol. The results indicate that higher hole densities (above and below the grate) lead to higher power outputs and lower specific CO emissions, but with lower thermal efficiency. Further, results indicate that adequate air holes below the grate (primary air) are more important for proper combustion in an imbaula; however this should be synchronised with secondary air in-lets (above the grid) in order to have congruence of all the performance criteria. This study should lead to the development of a set of criteria that can further enhance emissions reductions and fuel efficiency obtained by top-down stove ignition methods (Basa njengo Magogo) for imbaula type stoves

The landscape of gifted and talented education in England and Wales: How are teachers implementing policy?

This is an Author's Accepted Manuscript of an article published in Research Papers in Education, 27(2), 167-186, 2012, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/02671522.2010.509514.This paper explores the evidence relating to how primary schools are responding to the ‘gifted and talented’ initiative in England and Wales. A questionnaire survey which invited both closed and open-ended responses was carried out with a national sample of primary schools. The survey indicated an increasing proportion of coordinators, compared with a survey carried out in 1996, were identifying their gifted and talented children as well as having associated school policies. However, the survey also highlighted a number of issues which need addressing if the initiative is to achieve its objective of providing the best possible educational opportunities for children. For example, it was found that a significant number of practitioners were not aware of the existence of the National Quality Standards for gifted and talented education, provided by the UK government in 2007, and the subject-specific criteria provided by the UK’s Curriculum Authority for identification and provision have been largely ignored. The process of identifying children to be placed on the ‘gifted and talented’ register seems haphazard and based on pragmatic reasons. Analysis of teachers’ responses also revealed a range of views and theoretical positioning held by them, which have implications for classroom practice. As the ‘gifted and talented’ initiative in the UK is entering a second decade, and yet more significant changes in policy are introduced, pertinent questions need to be raised and given consideration

The caloric and sugar content of beverages purchased at different store-types changed after the sugary drinks taxation in Mexico

Background: Following the 2014 sugary drinks tax implementation in Mexico, promising reduction in the volume of purchases of taxed beverages were observed overall and at different store-types. However, the tax's effects on purchasing patterns of calories and sugar remain unclear. Methods: Using longitudinal data from Mexican households (n = 7038), we examined changes in volume, calories and total sugar of packaged beverages purchased from 2012 to 2016 overall and by store-type. We used fixed effects models to estimate means for volume, calories, and sugar of households. To address the potential selectivity from households shopping at different stores, we calculated inverse probability weights to model the purchases changes over time by store-type. Results: For taxed beverages, the volume of purchases declined by-49 ml and-30 ml in the first year and second year post tax (2014 and 2015, respectively), while purchases leveled off in the third year of the tax (2016). Calories and sugar from taxed beverage purchases decreased over time, with the majority of the declines occurring in the first two years post-tax implementation. The volume of untaxed beverage purchases increased, whereas changes in calories and total sugar of untaxed beverages were minimal. Store level purchases of taxed beverages significantly decreased in the first two years post taxation (2014 and to 2015) only in supermarkets and traditional stores. The steepest declines in purchases of taxed beverages in 2014 were observed at supermarkets (-40 ml or-45%). The volume of purchases of untaxed beverages increased over time in almost all store-types, while calories and sugar minimally decreased over time. Conclusion: Although the Mexican tax on SSBs has lowered the purchases of sugary drinks 3 years after the tax implementation, the tax should be strengthened and store-specific interventions should be implemented to further reduce SSBs purchases in the Mexican population

Guidelines for the provision of bypass roads at and through-ways in cities and towns

Papers presented virtually at the 41st International Southern African Transport Conference on 10-13 July 2023.Roads provide linkages between cities and towns, neighbouring countries, and to other points of interest. Up until the mid-20th century, roads forming part of the national network in South Africa generally passed through cities and towns. As these areas grew and traffic volumes increased, it became clear that bypasses would be necessary. In 1960 the National Transport Commission adopted its freeway policy which included the concept of bypass roads. Despite the adoption of the concept of bypass roads, the provision of these roads remained a controversial issue. The perceived benefits to the city or town of through traffic are weighed up against the benefit of a bypass to long-distance traffic in terms of travel time and cost, and road safety considerations. The aim of the paper is to provide guidelines for the planning and management of bypass roads and through-ways, as well as for the economic impact analysis of these roads. The paper refers to Christaller’s Central Places Theory which explains the spatial distribution of a system of cities and towns, as well as the road network linking these centres with one another. The assessment of the need for a bypass road is then addressed. Guidelines are provided on aspects such as land use development, road network planning, and route determination principles. An economic analysis framework, addressing both social cost-benefit analysis and economic impact analysis methodologies, is presented. Finally certain conclusions are reached. The paper is based on a research project, Project P2.5 of 2018: “Provision of bypass roads and through-ways in settlements, towns and cities”, conducted as part of the SANRAL Research Programme

Concurrent prescribing of opioids with other sedating medications after cancer diagnosis: a population-level analysis

Purpose: Cancer is a major reason for concurrent prescription of opioids with other sedating medications—particularly benzodiazepines and gabapentinoids—yet population-based assessments of the extent and predictors of concurrent prescribing among clinically and demographically diverse patients with cancer are lacking. Methods: We conducted a retrospective cohort study of patients with non-metastatic cancer using North Carolina cancer registry data linked with Medicare and private insurance claims (2013–2016). We used modified Poisson regression to assess associations of patient characteristic with adjusted relative risk (aRR) of new concurrent prescribing of opioids with benzodiazepines or gabapentinoids after diagnosis. Results: Overall, 15% of patients were concurrently prescribed opioids with benzodiazepines or gabapentinoids. Characteristics independently associated with an increased risk of concurrent prescribing included cancer type (e.g., aRR cervical vs. colorectal cancer: 1.55, 95% CI: 1.12–2.14); prior use of opioids (aRR: 2.43, 95% CI:2.21–2.67), benzodiazepines (aRR: 4.08, 95% CI: 3.72–4.48), or gabapentinoids (3.82, 95% CI: 3.31–4.39), and premorbid mental health conditions, including substance use disorder (aRR: 1.27, 95% CI: 1.05–1.54). Black and Hispanic patients were less likely to experience concurrent prescribing (aRR, Black vs. White: 0.35, 95% CI: 0.15–0.83; aRR, Hispanic vs. White: 0.75, 95% CI: 0.66–0.85). Conclusion: Approximately 1 in 7 patients with cancer was concurrently prescribed opioids with other sedating medications. Associations between patient characteristics and risk of concurrent prescribing highlight predictors of concurrent prescribing and suggest a rationale for systematic assessment of substance use history at diagnosis. Future research could explore inequitable pain and symptom management and investigate risk of adverse medication-related events

Funding for preventative Children’s Services and rates of children becoming looked after : a natural experiment using longitudinal area-level data in England

Background Children in care face adverse health outcomes, throughout the life-course, relative to the general population. In England, over the last decade, the rate of children entering care has increased. The rate of change differs markedly for older and younger children, who may also experience different preventative services. These services have been subject to inequitable spending reductions due to fiscal policies trailing the 2008 recession. Objective To assess the impact of cuts to prevention on rates of preschool children and adolescents entering care between 2012 and 2019. Participants and Setting Children aged 1–4 and 16–17 years, across 150 English upper-tier local authorities. Methods Our outcomes were annual rates of children entering care, aged 1–4 and 16–17. Our exposures were Children’s Services prevention spend per child under 5, and per child over 12. Regression models were used to quantify, within areas, associations between trends in prevention spend and trends in rates of children entering care, controlling for employment and child poverty rates. Results We found no association between changes in prevention spend per child under 5 and changes in care entry for 1–4-year-olds. However, spending reductions per child over 12 were associated with rising rates of 16–17-year-olds entering care. Every £10 per child decrease in prevention spend was associated with an estimated additional 1.9 per 100,000 children aged 16–17 entering care the following year (95% CI 0.7 to 2.9), equivalent to 1 in 25 care entries in this age group between 2012 and 2019. Conclusion This study offers evidence that rising rates of older children entering care has partly been driven by cuts to prevention services catering to their needs. Policies to tackle adverse trends should promote reinvestment in youth services, placing ordinary help on a robust statutory footing

Influence of a Brane Tension on Phantom and Massive Scalar Field Emission

We elaborate the signature of the extra dimensions and brane tension in the process of phantom and massive scalar emission in the spacetime of (4+n)-dimensional tense brane black hole. Absorption cross section, luminosity of Hawking radiation and cross section in the low-energy approximation were found. We envisage that parameter connected with the existence of a brane imprints its role in the Hawking radiation of the considered fields.Comment: 7 pages, * figures, RevTex, to be published in General Relativity and Gravitatio

Search for single top quarks in the tau+jets channel using 4.8 fb−1^{-1} of ppˉp\bar{p} collision data

We present the first direct search for single top quark production using tau leptons. The search is based on 4.8 fb$^{-1}$ of integrated luminosity collected in $p\bar{p}$ collisions at $\sqrt{s}$=1.96 TeV with the D0 detector at the Fermilab Tevatron Collider. We select events with a final state including an isolated tau lepton, missing transverse energy, two or three jets, one or two of them $b$ tagged. We use a multivariate technique to discriminate signal from background. The number of events observed in data in this final state is consistent with the signal plus background expectation. We set in the tau+jets channel an upper limit on the single top quark cross section of \TauLimObs pb at the 95% C.L. This measurement allows a gain of 4% in expected sensitivity for the observation of single top production when combining it with electron+jets and muon+jets channels already published by the D0 collaboration with 2.3 fb$^{-1}$ of data. We measure a combined cross section of \SuperCombineXSall pb, which is the most precise measurement to date.Comment: 12 pages, 5 figure

b-Jet Identification in the D0 Experiment

Algorithms distinguishing jets originating from b quarks from other jet flavors are important tools in the physics program of the D0 experiment at the Fermilab Tevatron p-pbar collider. This article describes the methods that have been used to identify b-quark jets, exploiting in particular the long lifetimes of b-flavored hadrons, and the calibration of the performance of these algorithms based on collider data.Comment: submitted to Nuclear Instruments and Methods in Physics Research

Measurement of Z/gamma*+jet+X angular distributions in ppbar collisions at sqrt{s}=1.96 TeV

We present the first measurements at a hadron collider of differential cross sections for Z+jet+X production in delta phi(Z, jet), |delta y(Z, jet)| and |y_boost(Z, jet)|. Vector boson production in association with jets is an excellent probe of QCD and constitutes the main background to many small cross section processes, such as associated Higgs production. These measurements are crucial tests of the predictions of perturbative QCD and current event generators, which have varied success in describing the data. Using these measurements as inputs in tuning event generators will increase the experimental sensitivity to rare signals.Comment: Published in Physics Letters B 682 (2010), pp. 370-380. 15 pages, 6 figure