Adjunctive corticosteroid treatment of clinical Pneumocystis jiroveci pneumonia in infants less than 18 months of age – a randomised controlled trial

Objectives. To determine the efficacy and safety of adjunctive corticosteroid therapy in clinical Pneumocystis jiroveci pneumonia (PCP) in infants exposed to HIV infection. Design. Double-blind randomised placebo-controlled trial. Methods. Infants with a clinical diagnosis of PCP, based on an ‘atypical' pneumonia with: (i) hypoxia out of proportion to the clinical findings on auscultation; (ii) C-reactive protein count less than 10 mg/l; (iii) lactate dehydrogenase level above 500 IU/l; (iv) compatible chest radiograph findings; and (v) positive HIV enzyme-linked immunosorbert assay (ELISA) were included in the study. Patients were randomised to receive either prednisone or placebo. The protocol provided for the addition of prednisone to the treatment at 48 hours if there was clinical deterioration or an independent indication for steroid therapy. Other treatment was carried out in accordance with established guidelines. The primary study endpoint was in-hospital survival. Secondary outcome was time from admission to the first day of mean oxygen saturation above 90% in room air. Results. One hundred patients were included, 47 in the prednisone and 53 in the placebo group. Patients in the prednisone group had a 43% better chance of survival than the placebo group (hazard ratio (HR) 0.57, 95% confidence interval (CI) 0.30 - 1.07, p=0.08). No significant differences could be demonstrated between groups with regard to other parameters of recovery. Conclusions. In HIV-exposed infants with clinical PCP, adjunctive corticosteroid treatment does not appear to add benefit regarding time to recovery or oxygen independency, but early administration may improve survival. A large multicentred trial is needed to confirm these findings.South African Medical Journal Vol. 98 (4) 2008: pp.287-29

Screening for childhood anaemia using copper sulphate densitometry

Objective. To evaluate copper sulphate densitometry to screen for childhood anaemia in a primary care setting, with a view to identifying children requiring definitive diagnostic testing and treatment. Design. A cross-sectional screening study. Results of densitometry with a copper sulphate solution of specific gravity (SG) 1.048, corresponding to a haemoglobin (Hb) concentration of 10 g/dl, were compared with laboratory Hb determination. Setting. Outpatient department of Pretoria Academic Hospital (73 children) and a local cr_che (27 children). Subjects. One hundred consecutive children, aged between 6 months and 6 years, with informed written consent by parents. Outcome measure(s). Accuracy of copper sulphate densitometry in screening for Hb concentration below 10 g/dl in terms of sensitivity, specificity, positive and negative predictive values, as well as likelihood ratio. Results. The prevalence of anaemia (Hb < 10 g/dl) was 17% (95% confidence interval (CI) 10.2; 25.8). Copper sulphate densitometry had a sensitivity of 88.2% (95% CI 62.3; 97.9), a specificity of 89.2% (95% CI 79.9; 94.6), a positive predictive value of 62.5% (95% CI 40.8; 80.5) and a negative predictive value of 97.4% (95%CI 90.0; 99.5) in screening for anaemia. The likelihood ratio of a positive screening test was 8.17. Conclusions. Copper sulphate densitometry was accurate in screening for childhood anaemia. (South African Medical Journal: 2002 92(12): 978-981

Similarity in the restrictiveness of bond covenants

We examine the economic determinants and consequences associated with the inclusion of covenants with similar levels of restrictiveness in bond contracts. Using a unique Moody’s bond covenant dataset, we develop measures that capture similarity in the restrictiveness of bond covenants relative to previously issued peer bonds. We document that the demand for similarity by issuers, their advisors and bond investors follows the predictions of sociological and economic theories. Further, consistent with similarity in covenants reducing bond investors’ information acquisition and processing costs, we show that bonds with more similar covenant restrictiveness receive lower yields at issuance. These bonds are also more likely to be held by long-term bond investors, such as insurance companies, and are characterized by greater liquidity in the secondary market, providing a partial explanation for the lower bond yields. Our results highlight the benefits of covenant similarity and suggest that the use of covenants with similar restrictiveness levels brings information acquisition and processing cost savings that may be larger than the monitoring benefits provided by covenants with more tailored features

Age-Related Differences in Arm and Trunk Responses to First and Repeated Exposure to Laterally Induced Imbalances

The objective of this study was to examine age-related differences in arm and trunk responses during first and repeated step induced balance perturbations. Young and older adults received 10 trials of unpredictable lateral platform translations. Outcomes included maximum arm and trunk displacement within 1 s of perturbation and at first foot lift off (FFLO), arm and neck muscle activity as recorded using electromyography (EMG), initial step type, balance confidence, and percentage of harness-assisted trials. Compared to young adults, older adults demonstrated greater arm and trunk angular displacements during the first trial, which were present at FFLO and negatively associated with balance confidence. Unlike young adults, recovery steps in older adults were directed towards the fall with a narrowed base of support. Over repeated trials, rapid habituation of first-trial responses of bilateral arm and trunk displacement and EMG amplitude was demonstrated in young adults, but was absent or limited in older adults. Older adults also relied more on harness assistance during balance recovery. Exaggerated arm and trunk responses to sudden lateral balance perturbations in older adults appear to influence step type and balance recovery. Associations of these persistently amplified movements with an increased reliance on harness assistance suggest that training to reduce these deficits could have positive effects in older adults with and without neurological disorders

On Albanese torsors and the elementary obstruction

We show that the elementary obstruction to the existence of 0-cycles of degree 1 on an arbitrary variety X (over an arbitrary field) can be expressed in terms of the Albanese 1-motives associated with dense open subsets of X. Arithmetic applications are given

Extensive Chaos in the Nikolaevskii Model

We carry out a systematic study of a novel type of chaos at onset ("soft-mode turbulence") based on numerical integration of the simplest one dimensional model. The chaos is characterized by a smooth interplay of different spatial scales, with defect generation being unimportant. The Lyapunov exponents are calculated for several system sizes for fixed values of the control parameter $\epsilon$. The Lyapunov dimension and the Kolmogorov-Sinai entropy are calculated and both shown to exhibit extensive and microextensive scaling. The distribution functional is shown to satisfy Gaussian statistics at small wavenumbers and small frequency.Comment: 4 pages (including 5 figures) LaTeX file. Submitted to Phys. Rev. Let

Assessing health and well-being among older people in rural South Africa

Background: The population in developing countries is ageing, which is likely to increase the burden of noncommunicable diseases and disability. Objective: To describe factors associated with self-reported health, disability and quality of life (QoL) of older people in the rural northeast of South Africa. Design: Cross-sectional survey of 6,206 individuals aged 50 and over. We used multivariate analysis to examine relationships between demographic variables and measures of self-reported health (Health Status), functional ability (WHODASi) and quality of life (WHOQoL). Results: About 4,085 of 6,206 people eligible (65.8%) completed the interview. Women (Odds Ratio (OR) 1.30, 95% CI 1.09, 1.55), older age (OR2.59, 95% CI 1.97, 3.40), lower education (OR1.62, 95% CI 1.31,2.00), single status (OR1.18, 95% CI 1.01, 1.37) and not working at present (OR1.29, 95% CI 1.06, 1.59) were associated with a low health status. Women were also more likely to report a higher level of disability (OR1.38, 95% CI 1.14, 1.66), as were older people (OR2.92, 95% CI 2.25, 3.78), those with no education (OR1.57, 95% CI 1.26, 1.97), with single status (OR1.25, 95% CI 1.06, 1.46) and not working at present (OR1.33, 95% CI 1.06, 1.66). Older age (OR1.35, 95% CI 1.06, 1.74), no education (OR1.39, 95% CI 1.11, 1.73), single status (OR1.28, 95% CI 1.10, 1.49), a low household asset score (OR1.52, 95% CI 1.19, 1.94) and not working at present (OR1.32; 95% CI 1.07, 1.64) were all associated with lower quality of life. Conclusions: This study presents the first population-based data from South Africa on health status, functional ability and quality of life among older people. Health and social services will need to be restructured to provide effective care for older people living in rural South Africa with impaired functionality and other health problems

The effect of videokeratoscope faceplate design on radius of curvature maps

A computer model using finite ray tracing methods was developed to simulate a videokeratoscope analysing an average cornea. Different faceplate designs were tested using five points in the faceplate subtending angles between 15 and 75 in 15 intervals at the corneal vertex. Image quality was assessed by adding the geometrical blurs of the 5 image points. Differences (error) between accurate sagittal radius of curvature and sagittal radius of curvature calculated by the van Saarloos algorithm were calculated for selected surfaces at the same corneal points. The calculations were repeated for the tangential radius of curvature. Differences equal or bigger than 0.02 mm were regarded as clinically significant. The surface that provided the sharpest image for an average cornea was a cylinder with the base 120 mm away from the corneal vertex and a diameter of 26 mm. Changing the faceplate design results in clinically significant differences for an average cornea

The effects of CO2, climate and land-use on terrestrial carbon balance, 1920-1992: An analysis with four process-based ecosystem models

The concurrent effects of increasing atmospheric CO2 concentration, climate variability, and cropland establishment and abandonment on terrestrial carbon storage between 1920 and 1992 were assessed using a standard simulation protocol with four process-based terrestrial biosphere models. Over the long-term(1920–1992), the simulations yielded a time history of terrestrial uptake that is consistent (within the uncertainty) with a long-term analysis based on ice core and atmospheric CO2 data. Up to 1958, three of four analyses indicated a net release of carbon from terrestrial ecosystems to the atmosphere caused by cropland establishment. After 1958, all analyses indicate a net uptake of carbon by terrestrial ecosystems, primarily because of the physiological effects of rapidly rising atmospheric CO2. During the 1980s the simulations indicate that terrestrial ecosystems stored between 0.3 and 1.5 Pg C yr−1, which is within the uncertainty of analysis based on CO2 and O2 budgets. Three of the four models indicated (in accordance with O2 evidence) that the tropics were approximately neutral while a net sink existed in ecosystems north of the tropics. Although all of the models agree that the long-term effect of climate on carbon storage has been small relative to the effects of increasing atmospheric CO2 and land use, the models disagree as to whether climate variability and change in the twentieth century has promoted carbon storage or release. Simulated interannual variability from 1958 generally reproduced the El Niño/Southern Oscillation (ENSO)-scale variability in the atmospheric CO2 increase, but there were substantial differences in the magnitude of interannual variability simulated by the models. The analysis of the ability of the models to simulate the changing amplitude of the seasonal cycle of atmospheric CO2 suggested that the observed trend may be a consequence of CO2 effects, climate variability, land use changes, or a combination of these effects. The next steps for improving the process-based simulation of historical terrestrial carbon include (1) the transfer of insight gained from stand-level process studies to improve the sensitivity of simulated carbon storage responses to changes in CO2 and climate, (2) improvements in the data sets used to drive the models so that they incorporate the timing, extent, and types of major disturbances, (3) the enhancement of the models so that they consider major crop types and management schemes, (4) development of data sets that identify the spatial extent of major crop types and management schemes through time, and (5) the consideration of the effects of anthropogenic nitrogen deposition. The evaluation of the performance of the models in the context of a more complete consideration of the factors influencing historical terrestrial carbon dynamics is important for reducing uncertainties in representing the role of terrestrial ecosystems in future projections of the Earth system