2,777 research outputs found
Boron Abundances in Diffuse Interstellar Clouds
We present a comprehensive survey of B abundances in diffuse interstellar
clouds from HST/STIS observations along 56 Galactic sight lines. Our sample is
the result of a complete search of archival STIS data for the B II resonance
line at 1362 angstroms, with each detection confirmed by the presence of
absorption from other dominant ions at the same velocity. The data probe a
range of astrophysical environments including both high-density regions of
massive star formation as well as low-density paths through the Galactic halo,
allowing us to clearly define the trend of B depletion onto interstellar grains
as a function of gas density. Many extended sight lines exhibit complex
absorption profiles that trace both local gas and gas associated with either
the Sagittarius-Carina or Perseus spiral arm. Our analysis indicates a higher
B/O ratio in the inner Sagittarius-Carina spiral arm than in the vicinity of
the Sun, which may suggest that B production in the current epoch is dominated
by a secondary process. The average gas-phase B abundance in the warm diffuse
ISM is consistent with the abundances determined for a variety of Galactic disk
stars, but is depleted by 60 percent relative to the solar system value. Our
survey also reveals sight lines with enhanced B abundances that potentially
trace recent production of B-11 either by cosmic-ray or neutrino-induced
spallation. Such sight lines will be key to discerning the relative importance
of the two production routes for B-11 synthesis.Comment: To be published in the proceedings of the IAU Symposium 268, Light
Elements in the Universe, C. Charbonnel, M. Tosi, F. Primas & C. Chiappini,
ed
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An Examination of Laude: Four Character Sketches for Solo Trumpet in B-flat or C by Stanley Friedman, together with Three Recitals of Selected Works by Joseph Haydn, George Fredrick Handel, Eric Ewazen, and Others
Stanley Friedman is a composer of many works, primarily for brass instruments, that have become part of the standard repertoire. Solus, for Trumpet Unaccompanied, for example, appears on many audition and competition lists, as do others of his works. On the other hand, Laude: Four Character Sketches for Solo Trumpet, commissioned by the International Trumpet Guild in 1980, is unfortunately not widely known among trumpet performers and educators. The intent of this study is to demonstrate, through discussion and analysis, the qualities and potential appeal of this lesser-known work and to renew interest in its performance. Among the six chapters is an overview of Laude, including an explanation of Friedman's peculiar titles for each movement: Nocturne for St. Thomas, Phantasie für Der Wiz, Berceuse for John Julius, and Rondo for Professor Nabob. Other chapters discuss the procedure for analysis of the work and probable sources for melodic material. The motivic development and form of each movement of the work are also explored. The final chapter includes recommendations for the performance of Laude and is followed by a summary and conclusion
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The Nature Press, Vol. 3
Nature News was a newsletter publication about activities at the Cheadle Center for Biodiveristy and Ecological Restoration
Improving Exposure for Transoral Oropharyngeal Surgery with the Floor of Mouth Window: A Cadaveric Feasibility Study
Background: Transoral robotic and laser surgery is rising in popularity due to the increasing incidence of Human Papilloma Virus (HPV) related oropharyngeal cancer. However, adequate exposure of the tongue base remains a major hurdle in many cases. This study introduces a novel surgical technique called the Floor of Mouth Window, which can be used to improve tongue base exposure at the time of transoral surgery. Methods: This is a preclinical anatomic cadaver study. Seven fresh cadavers were used for this study. Exposure of the tongue base was compared between conventional mouth gags – the Feyh-Kastenbauer and McIvor – and our novel procedure, the Floor of Mouth Window. Exposure was compared subjectively using endoscopic and extracorporeal photographs, as well as objective measurements of inter-incisor distance, and oral cavity volume. Results: The exposure achieved by the Floor of Mouth Window technique was superior to the mouth gags. Inter-incisor distance and oral cavity volume measurements were all more favorable with the Floor of Mouth Window. This technique allowed for successful transoral laser tongue base and tonsil resection without the use of gags or scopes. Conclusion: The Floor of Mouth Window is an adjunctive procedure that simply and reliably improved exposure for transoral oropharyngeal surgery in this cadaveric feasibility study. This improved exposure may help increase the adoption of transoral surgery and reduce the number of aborted cases due to anatomic limitations
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