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A fluorescing spot on the temple: a helpful reminder for a detailed history and physical exam
We discuss a woman with a history of non-melanoma skin cancer who presented with a new erythematous macule on her right temple. On examination with Wood lamp the well-demarcated macule fluoresced pink making neoplasm unlikely. Further history and physical examination suggested an inadvertent ink stain and the patient was spared a biopsy highlighting the importance of eliciting a good history and performing a detailed physical examination with additional tools such as a Wood lamp when necessary
Discovery of a very weak magnetic field on the Am star Alhena
Alhena ( Gem) was observed in the frame of the BRITE (BRIght Target
Explorer) spectropolarimetric survey, which gathers high resolution, high
signal-to-noise, high sensitivity, spectropolarimetric observations of all
stars brighter than V=4 to combine seismic and spectropolarimetric studies of
bright stars.
We present here the discovery of a very weak magnetic field \textbf{on} the
Am star Alhena, thanks to very high signal-to-noise spectropolarimetric data
obtained with Narval at T\'elescope Bernard Lyot (TBL). All previously studied
Am stars show the presence of ultra-weak (sub-Gauss) fields with Zeeman
signatures with an unexpected prominent positive lobe. However, Alhena presents
a slightly stronger (but still very weak, only a few Gauss) field with normal
Zeeman signatures with a positive and negative lobe, as found in stronger field
(hundreds or thousands of Gauss) stars. It is the first detection of a normal
magnetic signature in an Am star.
Alhena is thus a very interesting object, which might provide the clue to
understanding the peculiar shapes of the magnetic signatures of the other Am
stars.Comment: letter accepted by MNRA
Observations of magnetic fields in hot stars
The presence of magnetic fields at the surfaces of many massive stars has
been suspected for decades, to explain the observed properties and activity of
OB stars. However, very few genuine high-mass stars had been identified as
magnetic before the advent of a new generation of powerful spectropolarimeters
that has resulted in a rapid burst of precise information about the magnetic
properties of massive stars. During this talk, I will briefly review modern
methods used to diagnose magnetic fields of higher-mass stars, and summarize
our current understanding of the magnetic properties of OB stars.Comment: Proceedings of IAUS272: Active OB stars, review talk (11 pages
Combining seismology and spectropolarimetry of hot stars
Asteroseismology and spectropolarimetry have allowed us to progress
significantly in our understanding of the physics of hot stars over the last
decade. It is now possible to combine these two techniques to learn even more
information about hot stars and constrain their models. While only a few
magnetic pulsating hot stars are known as of today and have been studied with
both seismology and spectropolarimetry, new opportunities - in particular
Kepler2 and BRITE - are emerging and will allow us to rapidly obtain new
combined results.Comment: proceedings of the IAU Symposium 307 held in Geneva in June 201
Stochastic excitation of gravity waves in rapidly rotating massive stars
Stochastic gravity waves have been recently detected and characterised in
stars thanks to space asteroseismology and they may play an important role in
the evolution of stellar angular momentum. In this context, the observational
study of the CoRoT hot Be star HD 51452 suggests a potentially strong impact of
rotation on stochastic excitation of gravito-inertial waves in rapidly rotating
stars. In this work, we present our results on the action of the Coriolis
acceleration on stochastic wave excitation by turbulent convection. We study
the change of efficiency of this mechanism as a function of the waves' Rossby
number and we demonstrate that the excitation presents two different regimes
for super-inertial and sub-inertial frequencies. Consequences for rapidly
rotating early-type stars and the transport of angular momentum in their
interiors are discussed.Comment: 2 pages, 1 figure, IAU 307 symposium proceedings, 'New windows on
massive stars: asteroseismology, interferometry, and spectropolarimetry',
Eds. G. Meynet, C. Georgy, J.H. Groh & Ph. Ste
Wind tunnel evaluation of YF-12 inlet response to internal airflow disturbances with and without control
The response of terminal-shock position and static pressures in the subsonic duct of a YF-12 aircraft flight-hardware inlet to perturbations in simulated engine corrected airflow were obtained with and without inlet control. Frequency response data, obtained with inlet controls inactive, indicated the general nature of the inherent inlet dynamics, assisted in the design of controls, and provided a baseline reference for responses with active controls. All the control laws were implemented by means of a digital computer that could be programmed to behave like the flight inlet's existing analog control. The experimental controls were designed using an analytical optimization technique. The capabilities of the controls were limited primarily by the actuation hardware. The experimental controls provided somewhat better attenuation of terminal shock excursions than did the YF-13 inlet control. Controls using both the forward and aft bypass systems also provided somewhat better attenuation than those using just the forward bypass. The main advantage of using both bypasses is in the greater control flexibility that is achieved
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