140,405 research outputs found
Westerlund 1 as a Template for Massive Star Evolution
With a dynamical mass M_dyn ~ 1.3x10e5 M_sun and a lower limit M_cl>5x10e4
M_sun from star counts, Westerlund 1 is the most massive young open cluster
known in the Galaxy and thus the perfect laboratory to study massive star
evolution. We have developed a comprehensive spectral classification scheme for
supergiants based on features in the 6000-9000A range, which allows us to
identify >30 very luminous supergiants in Westerlund 1 and ~100 other less
evolved massive stars, which join the large population of Wolf-Rayet stars
already known. Though detailed studies of these stars are still pending,
preliminary rough estimates suggest that the stars we see are evolving to the
red part of the HR diagram at approximately constant luminosity.Comment: To be published in Proceedings of IAU Symposium 250: Massive Stars as
Cosmic Engines, held in Kaua'i (Hawaii, USA), Dec 2007, edited by F.
Bresolin, P.A. Crowther & J. Puls (Cambridge University Press
Development and Psychometric Properties of A Screening Tool for Assessing Developmental Coordination Disorder in Adults
Background: Developmental Coordination Disorder (DCD) is a neurodevelopmental disorder affecting motor coordination. Evidence suggests this disorder persists into adulthood and may be associated with biomechanical dysfunction and pain. We report on the development and initial validation of a questionnaire to assess for DCD in adults. Methods: An initial item pool (13 items) was derived from the American Psychiatric Association criteria and World Health Organisation definition for DCD. An expert panel assessed face and content validity which led to a 9-item Functional Difficulties Questionnaire (FDQ-9) with possible scores ranging from 9-36 (higher scores indicating greater functional difficulties). The FDQ-9 was piloted on individuals recruited from convenience samples. The underlying factor structure and aspects of reliability, validity and accuracy were tested. The Receiver Operating Characteristic Curve was employed to evaluate the diagnostic accuracy of the test using self-reported dyspraxia as the reference standard. Results: Principal Axis Factoring yielded a two factor solution relating to gross and fine motor skills; for conceptual parsimony these were combined. Internal reliability was high (0.81), the mean inter-item correlation was 0.51 and preliminary findings suggested satisfactory construct validity. The Area under the Curve was 0.918 [95% CI 0.84-1.00] indicating a diagnostic test with high accuracy. A cut-off score was established with a sensitivity and specificity of 86% [95% CI 78%-89%] and 81% [95 % CI 73%-89%] respectively. Test-retest reliability was good (ICC 0.96 [95% CI 0.92 to 0.98]. Conclusion: The psychometric properties of the FDQ-9 appear promising. Work is required to conduct further psychometric evaluations on new samples and apply the scale to clinical practice
Marriage a la mode
Marriage a la Mode is the fourth chapter in the biography of Thomas, Marquess of Wharton (Tom to his family and eventually to the political world of England). The chapter picks up the narrative about 1666, when young Tom returns from three years in France; and it deals with the attempts of Lord Wharton, his father, to negotiate a suitable seventeenth-century style marriage for him. Though the episodes deal with the Wharton family in particular, they illustrates some of the general problems of aristocratic marriages during the Restoration era; and they form a complete story in themselves.
The tables of abbreviations and short titles which are included to help the reader through the (voluminous) notes are the lists for the whole biography, not merely Marriage a la Mode.</p
The BaBar Calorimeter Light Pulser System
To make precision measurements with a CsI(Tl) calorimeter in a high
luminosity environment requires that the crystals are well calibrated and
continually monitored for radiation damage. This should not effect the total
integrated luminosity which is particularly important for the \babar
calorimeter to enable it to make CP violation measurements in the meson
system. To achieve this goal a fibre-optic light pulser system was designed
using xenon flash lamps as the light source. A novel light distribution method
was developed using an array of graded index microlenses. Some initial results
from performance studies are presented.Comment: 4 pages: 1 LaTeX file + 4 EPS figues + 1 style file + 1 EPS logo.
Talk given at "8th Pisa meeting on Advanced Detectors" (Elba, May 2000
- …