Pulsating Stellar Atmospheres

We review the basic concepts, the present state of theoretical models, and the future prospects for theory and observations of pulsating stellar atmospheres. Our emphasis is on radially pulsating cool stars, which dynamic atmospheres provide a general example for the differences with standard static model atmospheres.Comment: 9 pages, 2 figs, LaTex, in Proc. of IAU Symp 189, "Fundamental Stellar Properties...", eds. T. R. Bedding, A. J. Booth and J. Davis, Kluwer, p.253, 199

Analysis of Four A-F Supergiants in M31 from Keck HIRES Spectroscopy

The first stellar abundances in M31 are presented, based on Keck I HIRES spectroscopy and model atmospheres analyses of three A-F supergiants, 41-2368, 41-3712, and A-207. We also present the preliminary analysis of a fourth star, 41-3654. We find that the stellar oxygen abundances are in good agreement with those determined from nebular studies, even though the stars do {\it not} show a clear radial gradient in oxygen. The uncertainties in the stellar abundances are smaller than the range in the nebular results, making these stars ideal objects for further studies of the distribution of oxygen in M31. We show that the stars can be used to study the abundance distributions of other elements as well, including iron-group and heavier elements. The A-F supergiants also provide direct information on the metallicity and reddening of nearby Cepheid stars. We have examined the metallicity and reddening assumptions used for Cepheids within 1' of our targets and noted the differences from values used in the literature.Comment: Accepted for publication in the ApJ, October 2000 (23 pages, 4 tables, 11 figures

Quantitative Spectroscopy of BA-type Supergiants

Luminous BA-SGs allow topics ranging from NLTE physics and the evolution of massive stars to the chemical evolution of galaxies and cosmology to be addressed. A hybrid NLTE technique for the quantitative spectroscopy of BA-SGs is discussed. Thorough tests and first applications of the spectrum synthesis method are presented for four bright Galactic objects. Stellar parameters are derived from spectroscopic indicators. The internal accuracy of the method allows the 1sigma-uncertainties to be reduced to <1-2% in Teff and to 0.05-0.10dex in log g. Elemental abundances are determined for over 20 chemical species, with many of the astrophysically most interesting in NLTE. The NLTE computations reduce random errors and remove systematic trends in the analysis. Inappropriate LTE analyses tend to systematically underestimate iron group abundances and overestimate the light and alpha-process element abundances by up to factors of 2-3 on the mean. Contrary to common assumptions, significant NLTE abundance corrections of ~0.3dex can be found even for the weakest lines. NLTE abundance uncertainties amount to typically 0.05-0.10dex (random) and \~0.10dex (systematic 1sigma-errors). Near-solar abundances are derived for the heavier elements, and patterns indicative of mixing with nuclear-processed matter for the light elements. These imply a blue-loop scenario for Eta Leo, while the other three objects appear to have evolved directly from the main sequence. In the most ambitious computations several ten-thousand spectral lines are accounted for, permitting the accurate reproduction of the entire observed spectra from the visual to NIR. This prerequisite for the quantitative interpretation of medium-resolution spectra opens up BA-SGs as versatile tools for extragalactic stellar astronomy beyond the Local Group. (abridged)Comment: 36 pages, 18 figures, accepted for publication in A&

Impaired driving charges in injured impaired drivers requiring treatment in an emergency department

ABSTRACTObjective:To determine the percentage of injured impaired drivers brought to the only trauma centre in Nova Scotia who were charged with impaired driving.Methods:This retrospective observational study identified alcohol impaired drivers involved in a motor vehicle crash (MVC) brought to the emergency department (ED). Patients were selected based on blood alcohol concentrations (BACs) found to be above the legal limit. Medical records were examined to determine if the patient was the driver in an MVC. Patient records were then cross-referenced with a police database to determine the percentage of injured impaired drivers who were charged with impaired driving.Results:Between April 1, 2006, and April 1, 2008, 1,102 patients brought to the QEII Health Sciences Centre (QEII HSC) ED were found to have BACs over the legal limit. Of these patients, only 57 (5.2%) were found to have been the driver in an MVC. The majority of patients were male (49; 86%), with an average age of 32 years. Most injuries (51; 89.5%) were the result of a single-vehicle crash. The mean Glasgow Coma Scale score was 12.6, and the mean Injury Severity Score was 14.4. Cross-referencing with police records showed that only 22.8% (13 of 57) of injured drivers were charged with impaired driving. Those drivers not charged with impaired driving had a significantly lower median BAC and median age.Conclusion:During the study, the majority of alcoholimpaired drivers injured in an MVC who were brought to the QEII HSC ED for assessment of their injuries were not charged with impaired driving.</jats:sec

A survey of line profile variations in non-emission line B0–B5 III–V stars

Some investigators have attributed the photometric and spectral line profile variations (lpv) that are common among the B stars to nonradial pulsation while others have attempted to explain them by rotation of photospheric or circumstellar structures with respect to our line of sight. One of the problems in resolving this debate has been our lack of knowledge of how these variations depend on fundamental stellar characteristics. Surveys of lpv have covered the Be and a few Bn stars (D. Penrod, unpublished), the O stars (Fullerton 1990), and B8-B9.5 main sequence stars (Baade 1989), but noone has carried out a systematic search for lpv among the near main sequence, non-emission line early- and mid-B stars. This paper describes preliminary results from such a survey.</jats:p

Platypus Surfing: In Search of the Perfect Wave

For this project, we design a self-activated wave enrichment system for a solo male platypus, 'Sam', at Melbourne Zoo. We develop a sensor system that Sam can learn to activate by swimming near the device to trigger a wave sequence, providing both choice (to activate a wave pattern) and control (whether to activate) over his environment. We predict that the triggering will promote natural exploration and play behaviours in response to the wave patterns and reduce noted abnormal repetitive behaviours. The project involves multiple stakeholders with city and state zoos, Animal Welfare Specialists, keepers and operational systems teams, university researchers and multiple funding applications and ethical clearances. With the project 'still in process', we detail the initial testing which indicates the overall potential success of the interactive system for Sam and specify the next steps for implementation, observation, analysis and beyond