An investigation into wound infection and abscess formation in a mine

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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

Heterogeneous perturbations in the Doppler-free S1 ← S0 two-photon spectrum of benzene: Evidence for intrastate coupling

Rotational perturbations are identified in Doppler-free two-photon spectra of the 1410 and 1410110 vibronic bands in C6H6. Evidence is found that Coriolis coupling between some of the rotational levels of two distinct vibrational states within S1 is the mechanism responsible. This coupling mechanism is thought to be responsible for irreversible intramolecular relaxation at higher excess energies and higher vibrational state densities

Visual function and long-term chloroquine treatment

Ophthalmic examinations and selected tests of visual function were perfonned on 64 patients with rheumatoid arthritis who had received daily doses of 200 mg chloroquine sulphate for periods ranging from 3 to 11 months. Visual fields were determined by Humphrey automated perimetry and Amsler grids and a further battery of four tests of macular function (visual evoked potentials, critical flicker fusion threshold, Cambridge contrast sensitivity and the macular dazzle test) were administered. No case of retinal pigmentary abnormalities plus visual loss was found, but 2 patients were advised to cease chloroquine therapy on the basis of funduscopic findings. A small group of patients with relatively poor scores on one or more tests had normal visual fields and ophthalmic findings. There were no significant partial correlations between test results and the cumulative dose of chloroquine. These results support the opinion that currently recommended doses of chloroquine pose a minimal risk of retinal toxicity

Cigarette Smoking, Birthweight and Osteoporosis in Adulthood: Results from the Hertfordshire Cohort Study

We looked for interaction between early environment and adult lifestyle in determination of bone mineral content (BMC) and bone mineral density (BMD) among 498 men and 468 women for whom birth records were available. Participants completed a health questionnaire, and bone densitometry (DXA) of the lumbar spine and femoral neck performed

Cosmological Parameters Degeneracies and Non-Gaussian Halo Bias

We study the impact of the cosmological parameters uncertainties on the measurements of primordial non-Gaussianity through the large-scale non-Gaussian halo bias effect. While this is not expected to be an issue for the standard LCDM model, it may not be the case for more general models that modify the large-scale shape of the power spectrum. We consider the so-called local non-Gaussianity model and forecasts from planned surveys, alone and combined with a Planck CMB prior. In particular, we consider EUCLID- and LSST-like surveys and forecast the correlations among $f_{\rm NL}$ and the running of the spectral index $\alpha_s$, the dark energy equation of state $w$, the effective sound speed of dark energy perturbations $c^2_s$, the total mass of massive neutrinos $M_\nu=\sum m_\nu$, and the number of extra relativistic degrees of freedom $N_\nu^{rel}$. Neglecting CMB information on $f_{\rm NL}$ and scales $k > 0.03 h$/Mpc, we find that, if $N_\nu^{\rm rel}$ is assumed to be known, the uncertainty on cosmological parameters increases the error on $f_{\rm NL}$ by 10 to 30% depending on the survey. Thus the $f_{\rm NL}$ constraint is remarkable robust to cosmological model uncertainties. On the other hand, if $N_\nu^{\rm rel}$ is simultaneously constrained from the data, the $f_{\rm NL}$ error increases by $\sim 80$. Finally, future surveys which provide a large sample of galaxies or galaxy clusters over a volume comparable to the Hubble volume can measure primordial non-Gaussianity of the local form with a marginalized 1--$\sigma$ error of the order $\Delta f_{\rm NL} \sim 2-5$, after combination with CMB priors for the remaining cosmological parameters. These results are competitive with CMB bispectrum constraints achievable with an ideal CMB experiment.Comment: 17 pages, 1 figure added, typos corrected, comments added, matches the published versio

Hospitalisation without delirium is not associated with cognitive decline in a population-based sample of older people-results from a nested, longitudinal cohort study

Background: Acute hospitalisation and delirium have individually been shown to adversely affect trajectories of cognitive decline but have not previously been considered together. This work aimed to explore the impact on cognition of hospital admission with and without delirium, compared to a control group with no hospital admissions. Methods: The Delirium and Cognitive Impact in Dementia (DECIDE) study was nested within the Cognitive Function and Ageing Study II (CFAS II)-Newcastle cohort. CFAS II participants completed two baseline interviews, including the Mini-Mental State Examination (MMSE). During 2016, surviving participants from CFAS II-Newcastle were recruited to DECIDE on admission to hospital. Participants were reviewed daily to determine delirium status. During 2017, all DECIDE participants and age, sex and years of education matched controls without hospital admissions during 2016 were invited to repeat the CFAS II interview. Delirium was excluded in the control group using the Informant Assessment of Geriatric Delirium Scale (i-AGeD). Linear mixed effects modelling determined predictors of cognitive decline. Results: During 2016, 82 of 205 (40%) DECIDE participants had at least one episode of delirium. At 1 year, 135 of 205 hospitalised participants completed an interview along with 100 controls. No controls experienced delirium (i-AGeD>4). Delirium was associated with a faster rate of cognitive decline compared to those without delirium (β =-2.2, P < 0.001), but number of hospital admissions was not (P = 0.447). Conclusions: These results suggest that delirium during hospitalisation rather than hospitalisation per se is a risk factor for future cognitive decline, emphasising the need for dementia prevention studies that focus on delirium intervention

Deterministically Driven Avalanche Models of Solar Flares

We develop and discuss the properties of a new class of lattice-based avalanche models of solar flares. These models are readily amenable to a relatively unambiguous physical interpretation in terms of slow twisting of a coronal loop. They share similarities with other avalanche models, such as the classical stick--slip self-organized critical model of earthquakes, in that they are driven globally by a fully deterministic energy loading process. The model design leads to a systematic deficit of small scale avalanches. In some portions of model space, mid-size and large avalanching behavior is scale-free, being characterized by event size distributions that have the form of power-laws with index values, which, in some parameter regimes, compare favorably to those inferred from solar EUV and X-ray flare data. For models using conservative or near-conservative redistribution rules, a population of large, quasiperiodic avalanches can also appear. Although without direct counterparts in the observational global statistics of flare energy release, this latter behavior may be relevant to recurrent flaring in individual coronal loops. This class of models could provide a basis for the prediction of large solar flares.Comment: 24 pages, 11 figures, 2 tables, accepted for publication in Solar Physic