Spectral Classification; Old and Contemporary

Beginning with a historical account of the spectral classification, its refinement through additional criteria is presented. The line strengths and ratios used in two dimensional classifications of each spectral class are described. A parallel classification scheme for metal-poor stars and the standards used for classification are presented. The extension of spectral classification beyond M to L and T and spectroscopic classification criteria relevant to these classes are described. Contemporary methods of classifications based upon different automated approaches are introduced.Comment: To be published in "Principles and Perspectives in Cosmochemistry" Lecture Notes on Kodai School on Synthesis of Elements in Stars: Ed Aruna Goswami & Eswar Reddy, Springer Verlag, 2009, 17 pages, 10 figure

Impact of a Formal Patient Safety and Quality Improvement Curriculum: A Prospective, Controlled Trial

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149337/1/lary27527_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149337/2/lary27527.pd

Non-monotonic temperature evolution of dynamic correlations in glass-forming liquids

The viscosity of glass-forming liquids increases by many orders of magnitude if their temperature is lowered by a mere factor of 2-3 [1,2]. Recent studies suggest that this widespread phenomenon is accompanied by spatially heterogeneous dynamics [3,4], and a growing dynamic correlation length quantifying the extent of correlated particle motion [5-7]. Here we use a novel numerical method to detect and quantify spatial correlations which reveal a surprising non-monotonic temperature evolution of spatial dynamical correlations, accompanied by a second length scale that grows monotonically and has a very different nature. Our results directly unveil a dramatic qualitative change in atomic motions near the mode-coupling crossover temperature [8] which involves no fitting or indirect theoretical interpretation. Our results impose severe new constraints on the theoretical description of the glass transition, and open several research perspectives, in particular for experiments, to confirm and quantify our observations in real materials.Comment: 7 page

The Classification of T Dwarfs

We discuss methods for classifying T dwarfs based on spectral morphological features and indices. T dwarfs are brown dwarfs which exhibit methane absorption bands at 1.6 and 2.2 ${\mu}m$. Spectra at red optical (6300--10100 {\AA}) and near-infrared (1--2.5 ${\mu}m$) wavelengths are presented, and differences between objects are noted and discussed. Spectral indices useful for classification schemes are presented. We conclude that near-infrared spectral classification is generally preferable for these cool objects, with data sufficient to resolve the 1.17 and 1.25 ${\mu}m$ K I doublets lines being most valuable. Spectral features sensitive to gravity are discussed, with the strength of the K-band peak used as an example. Such features may be used to derive a two-dimensional scheme based on temperature and mass, in analogy to the MK temperature and luminosity classes.Comment: 15 pages, 6 figures, conference proceedings for IAU Ultracool Dwarf Stars session, ed. I. Steele & H. Jone

The Shapes of Cooperatively Rearranging Regions in Glass Forming Liquids

The shapes of cooperatively rearranging regions in glassy liquids change from being compact at low temperatures to fractal or ``stringy'' as the dynamical crossover temperature from activated to collisional transport is approached from below. We present a quantitative microscopic treatment of this change of morphology within the framework of the random first order transition theory of glasses. We predict a correlation of the ratio of the dynamical crossover temperature to the laboratory glass transition temperature, and the heat capacity discontinuity at the glass transition, Delta C_p. The predicted correlation agrees with experimental results for the 21 materials compiled by Novikov and Sokolov.Comment: 9 pages, 6 figure

Surface features, rotation and atmospheric variability of ultra cool dwarfs

Photometric I band light curves of 21 ultra cool M and L dwarfs are presented. Variability with amplitudes of 0.01 to 0.055 magnitudes (RMS) with typical timescales of an hour to several hours are discovered in half of these objects. Periodic variability is discovered in a few cases, but interestingly several variable objects show no significant periods, even though the observations were almost certainly sensitive to the expected rotation periods. It is argued that in these cases the variability is due to the evolution of the surface features on timescales of a few hours. This is supported in the case of 2M1145 for which no common period is found in two separate light curves. It is speculated that these features are photospheric dust clouds, with their evolution possibly driven by rotation and turbulence. An alternative possibility is magnetically-induced surface features. However, chromospheric activity undergoes a sharp decrease between M7 and L1, whereas a greater occurrence of variability is observed in objects later than M9, lending support to the dust interpretation.Comment: To appear in "Ultracool Dwarf Stars" (Lecture Notes in Physics), H.R.A. Jones, I. Steele (eds), Springer-Verlag, 2001. Also available from http://www.mpia-hd.mpg.de/homes/calj/ultra.htm

Use of ultrasound by emergency medical services: a review

Prehospital ultrasound has been deployed in certain areas of the USA and Europe. Physicians, emergency medical technicians, and flight nurses have utilized a variety of medical and trauma ultrasound assessments to impact patient care in the field. The goal of this review is to summarize the literature on emergency medical services (EMS) use of ultrasound to more clearly define the potential utility of this technology for prehospital providers

Use of ultrasound by emergency medical services: a review

Prehospital ultrasound has been deployed in certain areas of the USA and Europe. Physicians, emergency medical technicians, and flight nurses have utilized a variety of medical and trauma ultrasound assessments to impact patient care in the field. The goal of this review is to summarize the literature on emergency medical services (EMS) use of ultrasound to more clearly define the potential utility of this technology for prehospital providers

Hunger among Inuit children in Canada

Background and objectives. Inuit populations may be at increased risk for experiencing poor nutrition or hunger due to limited access and availability to food. The prevalence and correlates of parental perceptions of hunger among a nationally representative sample of Inuit children in Canada have not yet been reported. Design. Data are from the 2006 Aboriginal Children's Survey (ACS). Sociodemographic information, dietary behaviours and hunger status were parent-reported via a household interview for Inuit children aged 2–5 years (n=1,234). Prevalence of hunger was calculated among Inuit children by sociodemographic factors and by dietary behaviours. In addition, a multivariate logistic regression model was conducted to determine factors associated with parental perception of ever experiencing hunger. Results. The prevalence of Inuit children in Canada aged 2–5 years ever experiencing hunger was 24.4%. Children who were reported to have experienced hunger consumed milk and milk products (p<0.001); fish, eggs and meat (p<0.05); fruits (p<0.001); and vegetables (p<0.001) significantly less often than never-hungry children. Fast food and processed foods, soft drinks and juice, and salty snacks, sweets and desserts were consumed as often as never-hungry children (all p>0.05). The majority (81%) of Inuit parents/guardians of ever-hungry children sought help from family or friends. Factors associated with an increased likelihood of experiencing hunger include sociodemographic characteristics (such as income and household size), living in an Inuit region and living in a community with cultural activities. Conclusion. About 1 in 4 Inuit children were reported by their parents to have experienced hunger, and hunger was associated with region, sociodemographic and community factors. Future research could further examine the impact of ever experiencing hunger on the health status of Inuit children and their families in Canada