FT-IR spectroscopy of CAI and chondrules in primitive chondrites: techniques and first results

From the Introduction: Here we present preliminary mid-infrared spectra of CAI, chondrules and matrix from the CV3.2 carbonaceous chondrite Allende. This is part of our ongoing project to compile a database of infrared and optical spectra of minerals and components of primitive meteorites. These spectra should allow a better comparison with spectra from astronomical sources e.g. from dust and molecular clouds or young solar systems

Mid-infrared spectroscopy of CAI and AOA from the Allende CV3.2 chondrite

Mid-infrared spectra of bulk CAI from the CV3.2 chondrite Allende are presented and compared with astronomical spectra of cometary dust, zodiacal light,the circumstellar disk of beta Pictoris and dust around the red supergiant PR Per

An Atlas of Spectrophotometric Landolt Standard Stars

We present CCD observations of 102 Landolt standard stars obtained with the R-C spectrograph on the CTIO 1.5 m telescope. Using stellar atmosphere models we have extended the flux points to our six spectrophotometric secondary standards, in both the blue and the red, allowing us to produce flux-calibrated spectra that span a wavelength range from 3050 \AA to 1.1 \micron. Mean differences between UBVRI spectrophotometry computed using Bessell's standard passbands and Landolt's published photometry is found to be 1% or less. Observers in both hemispheres will find these spectra useful for flux-calibrating spectra and through the use of accurately constructed instrumental passbands be able to compute accurate corrections to bring instrumental magnitudes to any desired standard photometric system (S-corrections). In addition, by combining empirical and modeled spectra of the Sun, Sirius and Vega, we calculate and compare synthetic photometry to observed photometry taken from the literature for these three stars.Comment: Added referee's comments, minor corrections, replaced Table 1

The Determinants of HIV Treatment Costs in Resource Limited Settings

Background: Governments and international donors have partnered to provide free HIV treatment to over 6 million individuals in low and middle-income countries. Understanding the determinants of HIV treatment costs will help improve efficiency and provide greater certainty about future resource needs. Methods and Findings: We collected data on HIV treatment costs from 54 clinical sites in Botswana, Ethiopia, Mozambique, Nigeria, Uganda, and Vietnam. Sites provided free HIV treatment funded by the U.S. President’s Emergency Plan for AIDS Relief (PEPFAR), national governments, and other partners. Service delivery costs were categorized into successive six-month periods from the date when each site began HIV treatment scale-up. A generalized linear mixed model was used to investigate relationships between site characteristics and per-patient costs, excluding ARV expenses. With predictors at their mean values, average annual per-patient costs were $177 (95$353 (255–468) for adult patients in the first 6 months of ART, and $222 (161–296) for adult patients on ART for >6 months (excludes ARV costs). Patient volume (no. patients receiving treatment) and site maturity (months since clinic began providing treatment services) were both strong independent predictors of per-patient costs. Controlling for other factors, costs declined by 43% (18–63) as patient volume increased from 500 to 5,000 patients, and by 28% (6–47) from 5,000 to 10,000 patients. For site maturity, costs dropped 41% (28–52) between months 0–12 and 25% (15–35) between months 12–24. Price levels (proxied by per-capita GDP) were also influential, with costs increasing by 22% (4–41) for each doubling in per-capita GDP. Additionally, the frequency of clinical follow-up, frequency of laboratory monitoring, and clinician-patient ratio were significant independent predictors of per-patient costs. Conclusions: Substantial reductions in per-patient service delivery costs occur as sites mature and patient cohorts increase in size. Other predictors suggest possible strategies to reduce per-patient costs

Cost-effectiveness of community-based screening and treatment of moderate acute malnutrition in Mali.

IntroductionModerate acute malnutrition (MAM) causes substantial child morbidity and mortality, accounting for 4.4% of deaths and 6.0% of disability-adjusted life years (DALY) lost among children under 5 each year. There is growing consensus on the need to provide appropriate treatment of MAM, both to reduce associated morbidity and mortality and to halt its progression to severe acute malnutrition. We estimated health outcomes, costs and cost-effectiveness of four dietary supplements for MAM treatment in children 6-35 months of age in Mali.MethodsWe conducted a cluster-randomised MAM treatment trial to describe nutritional outcomes of four dietary supplements for the management of MAM: ready-to-use supplementary foods (RUSF; PlumpySup); a specially formulated corn-soy blend (CSB) containing dehulled soybean flour, maize flour, dried skimmed milk, soy oil and a micronutrient pre-mix (CSB++; Super Cereal Plus); Misola, a locally produced, micronutrient-fortified, cereal-legume blend (MI); and locally milled flour (LMF), a mixture of millet, beans, oil and sugar, with a separate micronutrient powder. We used a decision tree model to estimate long-term outcomes and calculated incremental cost-effectiveness ratios (ICERs) comparing the health and economic outcomes of each strategy.ResultsCompared to no MAM treatment, MAM treatment with RUSF, CSB++, MI and LMF reduced the risk of death by 15.4%, 12.7%, 11.9% and 10.3%, respectively. The ICER was US$9821 per death averted (2015 USD) and US$347 per DALY averted for RUSF compared with no MAM treatment.ConclusionMAM treatment with RUSF is cost-effective across a wide range of willingness-to-pay thresholds.Trial registrationNCT01015950

Spitzer Space Telescope spectral observations of AGB stars in the Fornax dwarf spheroidal galaxy

We have observed five carbon-rich AGB stars in the Fornax dwarf spheroidal (dSph) galaxy, using the Infrared Spectrometer on board the Spitzer Space Telescope. The stars were selected from a near-infrared survey of Fornax and include the three reddest stars, with presumably the highest mass-loss rates, in that galaxy. Such carbon stars probably belong to the intermediate-age population (2-8 Gyr old and metallicity of [Fe/H] -1) of Fornax. The primary aim of this paper is to investigate mass-loss rate, as a function of luminosity and metallicity, by comparing AGB stars in several galaxies with different metallicities. The spectra of three stars are fitted with a radiative transfer model. We find that mass-loss rates of these three stars are 4-7x10^-6 Msun yr-1. The other two stars have mass-loss rates below 1.3x10^-6 Msun yr-1. We find no evidence that these rates depend on metallicity, although we do suggest that the gas-to-dust ratio could be higher than at solar metallicity, in the range 240 to 800. The C2H2 bands are stronger at lower metallicity because of the higher C/O ratio. In contrast, the SiC fraction is reduced at low metallicity, due to low silicon abundance. The total mass-loss rate from all known carbon-rich AGB stars into the interstellar medium of this galaxy is of the order of 2x10^-5 Msun yr-1. This is much lower than that of the dwarf irregular galaxy WLM, which has a similar visual luminosity and metallicity. The difference is attributed to the younger stellar population of WLM. The suppressed gas-return rate to the ISM accentuates the difference between the relatively gas-rich dwarf irregular and the gas-poor dwarf spheroidal galaxies. Our study will be useful to constrain gas and dust recycling processes in low metallicity galaxies.Comment: MNRAS accepte