The Araucaria Project: the Local Group Galaxy WLM--Distance and metallicity from quantitative spectroscopy of blue Supergiants

The quantitative analysis of low resolution spectra of A and B supergiants is used to determine a distance modulus of 24.99 +/- 0.10 mag (995 +/- 46 Kpc) to the Local Group galaxy WLM. The analysis yields stellar effective temperatures and gravities, which provide a distance through the Flux weighted Gravity--Luminosity Relationship (FGLR). Our distance is 0.07 mag larger than the most recent results based on Cepheids and the tip of the RGB. This difference is within the 1-sigma overlap of the typical uncertainties quoted in these photometric investigations. In addition, non-LTE spectral synthesis of the rich metal line spectra (mostly iron, chromium and titanium) of the A supergiants is carried out, which allows the determination of stellar metallicities. An average metallicity of -0.87 +/- 0.06 dex with respect to solar metallicity is found.Comment: 46 pages, 14 figures (2 low resolution color figures). Accepted for publication by Ap

Hospital food service: a comparative analysis of systems and introducing the ‘Steamplicity’ concept

Background Patient meals are an integral part of treatment hence the provision and consumption of a balanced diet, essential to aid recovery. A number of food service systems are used to provide meals and the Steamplicity concept has recently been introduced. This seeks, through the application of a static, extended choice menu, revised patient ordering procedures, new cooking processes and individual patient food heated/cooked at ward level, to address some of the current hospital food service concerns. The aim of this small-scale study, therefore, was to compare a cook-chill food service operation against Steamplicity. Specifically, the goals were to measure food intake and wastage at ward level; ‘stakeholders’ (i.e. patients, staff, etc.) satisfaction with both systems; and patients’ acceptability of the food provided. Method The study used both quantitative (self-completed patient questionnaires, n = 52) and qualitative methods (semi-structured interviews, n = 16) with appropriate stakeholders including medical and food service staff, patients and their visitors. Results Patients preferred the Steamplicity system overall and in particular in terms of food choice, ordering, delivery and food quality. Wastage was considerably less with the Steamplicity system, although care must be taken to ensure that poor operating procedures do not negate this advantage. When the total weight of food consumed in the ward at each meal is divided by the number of main courses served, at lunch, the mean intake with the cook-chill system was 202 g whilst that for the Steamplicity system was 282 g and for the evening meal, 226 g compared with 310 g. Conclusions The results of this small study suggest that Steamplicity is more acceptable to patients and encourages the consumption of larger portions. Further evaluation of the Steamplicity system is warranted. The purpose of this study was to directly compare selected aspects (food wastage at ward level; satisfaction with systems and food provided) of a traditional cook-chill food service operation against ‘Steamplicity’. Results indicate that patients preferred the ‘Steamplicty’ system in all areas: food choice, ordering, delivery, food quality and overall. Wastage was considerably less with the ‘Steamplicity’ system; although care must be taken to ensure that poor operating procedures do not negate this advantage. When the total weight of food consumed in the ward at each meal is divided by the number of main courses served, results show that at lunch, mean intake with the cook-chill system was 202g whilst that for the ‘Steamplicity’ system was 282g and for the evening meal, 226g compared with 310g

Empirical modeling of the stellar spectrum of galaxies

An empirical method of modeling the stellar spectrum of galaxies is proposed, based on two successive applications of Principal Component Analysis (PCA). PCA is first applied to the newly available stellar library STELIB, supplemented by the J, H and K$_{s}$ magnitudes taken mainly from the 2 Micron All Sky Survey (2MASS). Next the resultant eigen-spectra are used to fit the observed spectra of a sample of 1016 galaxies selected from the Sloan Digital Sky Survey Data Release One (SDSS DR1). PCA is again applied, to the fitted spectra to construct the eigen-spectra of galaxies with zero velocity dispersion. The first 9 galactic eigen-spectra so obtained are then used to model the stellar spectrum of the galaxies in SDSS DR1, and synchronously to estimate the stellar velocity dispersion, the spectral type, the near-infrared SED, and the average reddening. Extensive tests show that the spectra of different type galaxies can be modeled quite accurately using these eigen-spectra. The method can yield stellar velocity dispersion with accuracies better than 10%, for the spectra of typical S/N ratios in SDSS DR1.Comment: 34 pages with 18 figures, submitted to A

An Accurate, Easy to Use Abundace Scale for Globular Clusters Based on 2.2um Spectra of Giant Stars

We present a new method for the determination of [Fe/H] for globular clusters. This new method is based on moderate resolution (R~1500) near-IR spectroscopy in the K-band of 6 to 10 of the brightest giants in a cluster. Our calibration is derived from spectra of 105 stars in 15 globular clusters. From measurements of the equivalent widths of three features in these spectra, Na, Ca, and CO, we are able to reproduce the Zinn & West (1984) abundance scale as updated by Harris (1996) to better than 0.10 dex for clusters with near solar [Fe/H] down to an [Fe/H] of -1.8. Three advantages of this method are that it can be used for metal rich, heavily reddened globulars in crowded fields, it does not require any knowledge of any other cluster or stellar parameters such as reddening, distance, or luminosity, and it requires only minimal telescope time. If stellar (J-K)0 and MK values are available as well, the accuracy of the [Fe/H] estimate is further improved. Observations of as few as three stars per cluster still gives an [Fe/H] estimate wich is nearly as reliable as that based on two to three times as many stars. The accuracy of an [Fe/H] value based on observations of CO absorption alone is significantly less than that which results from the three spectroscopic indices. However, we predict that space-based observations of this feature in the integrated light of stellar systems will prove to be of great value for abundance determinations at distances as far as the Coma cluster of galaxies.Comment: 53 pages, 16 Postscript figures. Submitted to the A

The rapidly pulsating sdO star, SDSS J160043.6+074802.9

A spectroscopic analysis of SDSS J160043.6+074802.9, a binary system containing a pulsating subdwarf-O (sdO) star with a late-type companion, yields Teff = 70 000 +/- 5000 K and log g = 5.25 +/- 0.30, together with a most likely type of K3V for the secondary star. We compare our results with atmospheric parameters derived by Fontaine et al. (2008) and in the context of existing evolution models for sdO stars. New and more extensive photometry is also presented which recovers most, but not all, frequencies found in an earlier paper. It therefore seems probable that some pulsation modes have variable amplitudes. A non-adiabatic pulsation analysis of uniform metallicity sdO models show those having log g > 5.3 to be more likely to be unstable and capable of driving pulsation in the observed frequency range.Comment: 14 pages, 12 figures, accepted for publication in MNRAS, 2009 September

Use of materials in nest construction by Pied Flycatchers Ficedula hypoleuca reflects localised habitat and geographical location.

Capsule Pied Flycatchers use different materials to construct their nests according to localised habitat and geographical location. Aims This study tested the hypotheses that birds would use the leaves they normally encountered within their breeding territories and that nest composition varied between geographical locations. Methods In Lancashire, Pied Flycatcher nests were collected from nestboxes built in locations dominated by different tree species and were deconstructed to determine which materials were used. Results Materials found in nests generally reflected the localised habitat around the nest rather than showing evidence of active collection from distant sources of material. Nests from Lancashire were significantly different in composition when compared with published data for nests from north Wales and central Spain. The use of moss was dominated by the use of one species in all but two nests. Conclusion Pied Flycatchers exhibit plasticity in nest construction behaviour because they were opportunistic in their choice of most nesting materials although they may be selective in their choice of moss

Effect of egg turning and incubation time on carbonic anhydrase gene expression in the blastoderm of the Japanese quail (Coturnix c. japonica)

(1) The gene expression of carbonic anhydrase, a key enzyme for the production sub-embryonic fluid (SEF), was assessed in turned and unturned eggs of the Japanese quail. The plasma membrane-associated isoforms CA IV, CAIX, CA XII, CA XIV, and the cytoplasmic isoform CA II, were investigated in the extra-embryonic tissue of the blastoderm and in embryonic blood. (2) Eggs were incubated at 37.6C, c. 60% R.H., and turned hourly (90 ) or left unturned. From 48 to 96 hours of incubation mRNA was extracted from blastoderm tissue, reverse-transcribed to cDNA and quantified by real-time qPCR using gene-specific primers. Blood collected at 96h was processed identically. (3) Blastoderm CAIV gene expression increased with the period of incubation only in turned eggs, with maxima at 84 and 96h of incubation. Only very low levels were found in blood. (4) Blastoderm CA II gene expression was greatest at 48 and 54h of incubation, subsequently declining to much lower levels and una ected by turning. Blood CA II gene expression was about 25-fold greater than that in the blastoderm. (5) The expression of CA IX in the blastoderm was the highest of all isoforms, yet unaffected by turning. CA XII did not amplify and CA XIV was present at unquantifiable low levels. (6) It is concluded that solely gene expression for CA IV is sensitive to egg turning, and that increased CA IV gene expression could account for the additional SEF mass found at 84-96h of incubation. in embryos of turned eggs

First-egg date and air temperature affect nest construction in Blue Tits Cyanistes caeruleus, but not in Great Tits Parus major

Capsule For nest construction by Blue Tits, but not Great Tits, first-egg date (FED) and air temperature significantly affected the mass of the nest as a whole and some of its component parts. Aims To test the hypothesis that use of nest materials is influenced by prevailing climatic conditions during nest construction. Methods Nests used in the study were built by Blue Tits Cyanistes caeruleus and Great Tits Parus major in nestboxes at a site in Lincolnshire, England during the 2008 and 2009 breeding seasons. Nests were dissected into their component parts and then weighed. Results Stepwise discriminant analysis showed that the asses of grasses, feathers and bark were significantly affected by species (all higher in Blue Tits) and year significantly affected the mass of wool and dust in the nests. ANOVA showed that total mass of the nest was not significantly affected by year of construction or species. By contrast, species, but not year, did significantly influence the masses of animal- and plant-derived materials in the nest. In Blue Tit nests there were significant correlations between FED and the mass of animal-derived material in 2008, but with plant-derived material in 2009. There were significant correlations between mean air temperature recorded during the seven days up to FED and the mass of the nests and their plant-derived materials. No significant correlations were observed between FED and nest components for Great Tits. Conclusion Nest construction is potentially affected by a variety of environmental factors, which may impact upon how nests function. A better understanding of how nest variability affects its function may allow better assessment of how climate change may impact upon the reproductive performance of bird

Determination of rotation periods in solar-like stars with irregular sampling: the Gaia case

We present a study on the determination of rotation periods (P) of solar-like stars from the photometric irregular time-sampling of the ESA Gaia mission, currently scheduled for launch in 2013, taking into account its dependence on ecliptic coordinates. We examine the case of solar-twins as well as thousands of synthetic time-series of solar-like stars rotating faster than the Sun. In the case of solar twins we assume that the Gaia unfiltered photometric passband G will mimic the variability of the total solar irradiance (TSI) as measured by the VIRGO experiment. For stars rotating faster than the Sun, light-curves are simulated using synthetic spectra for the quiet atmosphere, the spots, and the faculae combined by applying semi-empirical relationships relating the level of photospheric magnetic activity to the stellar rotation and the Gaia instrumental response. The capabilities of the Deeming, Lomb-Scargle, and Phase Dispersion Minimisation methods in recovering the correct rotation periods are tested and compared. The false alarm probability (FAP) is computed using Monte Carlo simulations and compared with analytical formulae. The Gaia scanning law makes the rate of correct detection of rotation periods strongly dependent on the ecliptic latitude (beta). We find that for P ~ 1 d, the rate of correct detection increases with ecliptic latitude from 20-30 per cent at beta ~ 0{\deg} to a peak of 70 per cent at beta=45{\deg}, then it abruptly falls below 10 per cent at beta > 45{\deg}. For P > 5 d, the rate of correct detection is quite low and for solar twins is only 5 per cent on average.Comment: 12 pages, 18 figures, accepted by MNRA

Environmental conditions but not nest composition affect reproductive success in an urban bird

Adjusting the composition of their nests, breeding birds can influence the environmental conditions that eggs and offspring experience. Birds often use feathers to build nests, presumably due to their insulating properties. The amount of feathers in nests is often associated with increased nestling survival and body condition. However, it is unclear whether these putative beneficial effects of adding feathers to nests are relevant in a wide range of environmental conditions. Here, we combine data on weather conditions and feathers in nests (i.e., nest composition) to investigate their relative contribution to reproductive success in the Eurasian tree sparrow (Passer montanus). Specifically, we investigate whether the effect of weather conditions on breeding success is modulated by the amount of feathers added to the nest. We found a strong negative effect of rainfall on the number of nestlings that successfully fledged per breeding attempt, but this negative effect was not mitigated by the amount of feathers in nests. We also found that the amount of feathers in nests varied along the breeding season, with nests containing more feathers early in the breeding season, when temperatures were lower. Despite considerable variation in nest composition, our results do not suggest an important role of feathers in nests protecting eggs or nestling tree sparrows against fluctuations in environmental conditions