B-type supergiants in the SMC: Rotational velocities and implications for evolutionary models

High-resolution spectra for 24 SMC and Galactic B-type supergiants have been analysed to estimate the contributions of both macroturbulence and rotation to the broadening of their metal lines. Two different methodologies are considered, viz. goodness-of-fit comparisons between observed and theoretical line profiles and identifying zeros in the Fourier transforms of the observed profiles. The advantages and limitations of the two methods are briefly discussed with the latter techniques being adopted for estimated projected rotational velocities (\vsini) but the former being used to estimate macroturbulent velocities. Only one SMC supergiant, SK 191, shows a significant degree of rotational broadening (\vsini $\simeq$ 90 \kms). For the remaining targets, the distribution of projected rotational velocities are similar in both our Galactic and SMC samples with larger values being found at earlier spectral types. There is marginal evidence for the projected rotational velocities in the SMC being higher than those in the Galactic targets but any differences are only of the order of 5-10 \kms, whilst evolutionary models predict differences in this effective temperature range of typically 20 to 70 \kms. The combined sample is consistent with a linear variation of projected rotational velocity with effective temperature, which would imply rotational velocities for supergiants of 70 \kms at an effective temperature of 28 000 K (approximately B0 spectral type) decreasing to 32 \kms at 12 000 K (B8 spectral type). For all targets, the macroturbulent broadening would appear to be consistent with a Gaussian distribution (although other distributions cannot be discounted) with an $\frac{1}{e}$ half-width varying from approximately 20 \kms at B8 to 60 \kms at B0 spectral types.Comment: 4 figures, 8 pages, submitted to Astronomy and Astrophysic

Incidence and risk factors of delirium in patients post pancreaticoduodenectomy

AbstractBackgroundPost-operative delirium is an important and common complication of major abdominal surgery characterized by acute confusion with fluctuating consciousness. The aim of this study was to establish the incidence of post-operative delirium in patients undergoing a pancreaticoduodenectomy and to determine the risk factors for its development.MethodsFrom a prospectively maintained database, a retrospective cohort analysis was performed of 50 consecutive patients who underwent a pancreaticoduodenectomy at the National Surgical Centre for Pancreatic Cancer in St. Vincent's University Hospital, Dublin and whose entire post-operative stay was in this institution, between July 2011 and December 2012. Two independent medical practitioners assessed all data and delirium was diagnosed according to criteria of the Diagnostic and Statistical Manual Disorder (DSM), fourth edition. Univariate and multivariate analyses were performed.ResultsSeven patients (14%) developed post-operative delirium. The median onset was on the second post-operative day. Older age was predictive of an increased risk of delirium post-operatively. Those who developed delirium had a significantly increased length of stay (LOS) as well as a significantly increased risk of developing at least a grade 3 complication (Clavien-Dindo classification).ConclusionThis study demonstrates that post-operative delirium is associated with a more complicated recovery after a pancreaticoduodenectomy and that older age is independently predictive of its development. Focused screening may allow targeted preventative strategies to be used in the peri-operative period to reduce complications and costs associated with delirium

Genetics, recombination and clinical features of human rhinovirus species C (HRV-C) infections; interactions of HRV-C with other respiratory viruses

To estimate the frequency, molecular epidemiological and clinical associations of infection with the newly described species C variants of human rhinoviruses (HRV), 3243 diagnostic respiratory samples referred for diagnostic testing in Edinburgh were screened using a VP4-encoding region-based selective polymerase chain reaction (PCR) for HRV-C along with parallel PCR testing for 13 other respiratory viruses. HRV-C was the third most frequently detected behind respiratory syncytial virus (RSV) and adenovirus, with 141 infection episodes detected among 1885 subjects over 13 months (7.5%). Infections predominantly targeted the very young (median age 6–12 months; 80% of infections in those <2 years), occurred throughout the year but with peak incidence in early winter months. HRV-C was detected significantly more frequently among subjects with lower (LRT) and upper respiratory tract (URT) disease than controls without respiratory symptoms; HRV-C mono-infections were the second most frequently detected virus (behind RSV) in both disease presentations (6.9% and 7.8% of all cases respectively). HRV variants were classified by VP4/VP2 sequencing into 39 genotypically defined types, increasing the current total worldwide to 60. Through sequence comparisons of the 5′untranslated region (5′UTR), the majority grouped with species A (n = 96; 68%, described as HRV-Ca), the remainder forming a phylogenetically distinct 5′UTR group (HRV-Cc). Multiple and bidirectional recombination events between HRV-Ca and HRV-Cc variants and with HRV species A represents the most parsimonious explanation for their interspersed phylogeny relationships in the VP4/VP2-encoding region. No difference in age distribution, seasonality or disease associations was identified between HRV-Ca and HRV-Cc variants. HRV-C-infected subjects showed markedly reduced detection frequencies of RSV and other respiratory viruses, providing evidence for a major interfering effect of HRV-C on susceptibility to other respiratory virus infections. HRV-C's disease associations, its prevalence and evidence for interfering effects on other respiratory viruses mandates incorporation of rhinoviruses into future diagnostic virology screening

Terminal velocities of luminous, early-type SMC stars

Ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) are used to determine terminal velocities for 11 O and B-type giants and supergiants in the Small Magellanic Cloud (SMC) from the Si IV and C IV resonance lines. Using archival data from observations with the Goddard High-Resolution Spectrograph and the International Ultraviolet Explorer telescope, terminal velocities are obtained for a further five B-type supergiants. We discuss the metallicity dependence of stellar terminal velocities, finding no evidence for a significant scaling between Galactic and SMC metallicities for Teff < 30,000 K, consistent with the predictions of radiation driven wind theory for supergiant stars. A comparison of the $v_\infty / v_{esc}$ ratio between the SMC and Galactic samples, while consistent with the above statement, emphasizes that the uncertainties in the distances to galactic O-stars are a serious obstacle to a detailed comparison with theory. For the SMC sample there is considerable scatter in this ratio at a given effective temperature, perhaps indicative of uncertainties in stellar masses.Comment: 28 pages, 8 figures, accepted by ApJ; minor revisions prior to acceptanc

Statistical properties of a sample of periodically variable B-type supergiants - Evidence for opacity-driven gravity-mode oscillations

We have studied a sample of 28 periodically variable B-type supergiants selected from the HIPPARCOS mission and 12 comparison stars covering the whole B-type spectral range. Our goal is to test if their variability is compatible with opacity-driven non-radial oscillations. We have used the NLTE atmosphere code FASTWIND to derive the atmospheric and wind parameters of the complete sample through line profile fitting. We applied the method to selected H, He and Si line profiles, measured with the high resolution CES spectrograph attached to the ESO CAT telescope in La Silla, Chile. From the location of the stars in the (log Teff, log g) diagram, we suggest that variability of our sample supergiants is indeed due to the gravity modes resulting from the opacity mechanism. We find nine of the comparison stars to be periodically variable as well, and suggest them to be new alpha Cyg variables. We find marginal evidence of a correlation between the amplitude of the photometric variability and the wind density. We investigate the Wind Momentum Luminosity Relation for the whole range of B spectral type supergiants, and find that the later types (> B5) perfectly follow the relation for A supergiants. Additionally, we provide a new spectral type - Teff calibration for B supergiants. Our results imply the possibility to probe internal structure models of massive stars of spectral type B through seismic tuning of gravity modes.Comment: 33 pages (including 14 pages online material). Accepted for publication in Astronomy & Astrophysic

Collective pulsational velocity broadening due to gravity modes as a physical explanation for macroturbulence in hot massive stars

We aimed at finding a physical explanation for the occurrence of macroturbulence in the atmospheres of hot massive stars, a phenomenon found in observations since more than a decade but yet unexplained. We computed time series of line profiles for evolved massive stars broadened by rotation and by hundreds of low-amplitude nonradial gravity-mode pulsations which are predicted to be excited for evolved massive stars. In general, line profiles based on macrotubulent broadening can mimic those subject to pulsational broadening. In several cases, though, good fits require macroturbulent velocities that pass the speed of sound for realistic pulsation amplitudes. Moreover, we find that the rotation velocity can be seriously underestimated by using a simple parameter description for macroturbulence rather than an appropriate pulsational model description to fit the line profiles. We conclude that macroturbulence is a likely signature of the collective effect of pulsations. We provide line diagnostics and their typical values to decide whether or not pulsational broadening is present in observed line profiles, as well as a procedure to avoid an inaccurate estimation of the rotation velocity.Comment: 12 pages, 9 figures, accepted for publication by Astronomy and Astrophysic

Fear of cancer recurrence following allogeneic haematopoietic stem cell transplantation (HSCT) for haematological malignancy: A cross-sectional study.

PURPOSE:The aim of this study was to quantify the prevalence of Fear of Cancer Recurrence (FCR) in patients with a prior haematology malignancy surviving more than one year post allogeneic haematopoietic stem cell transplantation (HSCT), and to identify the demographic, medical and psychological factors associated with FCR occurrence. METHOD:Participants were adult allogeneic HSCT recipients who had undergone the procedure for acute leukaemia or other haematological malignancy between the years 2000-2012 in Sydney, Australia. They completed a purpose designed survey and six other validated instruments which assessed FCR, psychological functioning, quality of life, demographic, social and clinical variables. RESULTS:Of the 364 respondents, approximately 11% of the sample lived with severe FCR while only 5% of subjects reported having no FCR. Variables significantly associated with higher FCR included unemployment, a shorter time (years) post-transplant, not attending to health screening (PAP smear), a secondary diagnosis of skin cancer, younger age, referral to a psychiatrist and taking psychotropic medication. Higher psychological distress (depression, anxiety, stress) and lower quality of life made a significant contribution to the prediction of FCR. CONCLUSIONS:Post HSCT follow-up care should include an assessment and discussion regarding FCR to balance both realistic and unrealistic cancer recurrence risks. Managing FCR is one of the most ubiquitous unmet needs of survivors of haematological disease and it is important that HSCT nurses are both aware of the fear, and are equipped with knowledge on how to help patients navigate it with realistic expectations

Understanding B-type Supergiants in the Low Metallicity Environment of the SMC

Spectroscopic analyses of 7 SMC B-type supergiants and 1 giant have been undertaken using high resolution optical data obtained on the VLT with UVES. FASTWIND, a non-LTE, spherical,line-blanketed model atmosphere code was used to derive atmospheric and wind parameters of these stars as well as their absolute abundances. The implications of these results for stellar evolution and line driven wind theory are discussed.Comment: 19 pages, 6 tables, 10 figures, accepted for publication in Astronomy and Astrophysics (5/12/2003

A Spectroscopic Study of Mass Outflows in the Interacting Binary RY Scuti

The massive interacting binary RY Scuti is an important representative of an active mass-transferring system that is changing before our eyes and which may be an example of the formation of a Wolf-Rayet star through tidal stripping. Utilizing new and previously published spectra, we present examples of how a number of illustrative absorption and emission features vary during the binary orbit. We identify spectral features associated with each component, calculate a new, double-lined spectroscopic binary orbit, and find masses of 7.1 +/- 1.2 M_sun for the bright supergiant and 30.0 +/- 2.1 M_sun for the hidden massive companion. Through tomographic reconstruction of the component spectra from the composite spectra, we confirm the O9.7 Ibpe spectral class of the bright supergiant and discover a B0.5 I spectrum associated with the hidden massive companion; however, we suggest that the latter is actually the spectrum of the photosphere of the accretion torus immediately surrounding the massive companion. We describe the complex nature of the mass loss flows from the system in the context of recent hydrodynamical models for beta Lyr, leading us to conclude RY Scuti has matter leaving the system in two ways: 1) a bipolar outflow from winds generated by the hidden massive companion, and 2) mass from the bright O9.7 Ibpe supergiant flowing from the region near the L2 point to fill out a large, dense circumbinary disk. This circumbinary disk (radius ~ 1 AU) may feed the surrounding double-toroidal nebula (radius ~ 2000 AU).Comment: 41 pages with 7 tables and 11 figures, accepted to Ap

Differential O and Si Abundances in M33 Early B Supergiants

We present non-LTE analyses of four M33 early B-supergiant stars and five Galactic counterparts. This is the first time that B supergiants beyond the Magellanic Clouds are analyzed by means of detailed Non-LTE techniques. Stellar temperatures, gravities, microturbulences and Si abundances are derived for all objects using the Si ionization equilibrium and the Balmer line wings. O abundances are then also derived. Important approximations made during the calculations are described, and their influence on the results is analyzed. It is found that these approximations have no significant effect on the results at any microturbulence. We find that a strict differential analysis is needed to detect abundance differences. Thus we compare results line by line in M33 and Galactic stars of stellar parameters as similar as possible. Three of the four M33 stars turned out to be O deficient as compared to their Galactic counterparts, and only one, close to the center of M33 (M33 1054) is found to be moderately O enriched. From these differential analyses we find that our data are compatible with a radial O gradient in M33 as that derived from HII region data: we obtain -0.19+/-0.13 or -0.20+/-0.07 dex/kpc, depending on whether B133 is included or not. Our data are also consistent with other possibilities such as a steep increase of the O abundance in the inner region (at projected distances less than 9 arcmin from the center of M33), followed by a flat O abundance profile towards the outer parts of M33. Si shows the same pattern, and it is shown that Si and O correlate well, as expected for alpha-elements, supporting then the high value of the O abundance gradient in M33 as compared to the Milky Way and other nearby spiral galaxies.Comment: Accepted for ApJ. Tentatively scheduled for Dec. 20, 2000. 44 pages, 9 tables, 18 figure