Philippe Petit

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We report the discovery of a medium-strength (∼0.5 kG) magnetic field on the young, massive star τ Sco (B0.2 V), which becomes the third-hottest magnetic star known. Circularly polarized Zeeman signatures are clearly detected in observations collected mostly with the ESPaDOnS spectropolarimeter, recently installed on the 3.6-m Canada–France–Hawaii(More)
– Samples of single-wall carbon nanotubes containing tubes with an " armchair " wrapping have been produced and exhibit metallic behavior with an intrinsic resistivity which increases approximately linearly with temperature over a wide temperature range. Here we study the coupling of the conduction electrons to long-wavelength torsional shape fluctuations,(More)
We describe the operation of a cold atom clock in reduced gravity. We have recorded the cesium hyperfine resonance signal at a frequency near 9.2 GHz in the ∼ 10 −2 g gravity environment produced by jet plane parabolic flights. With a resonance width of 7 Hz, the device operated in a regime which is not accessible on earth. In the much lower gravity level(More)
This paper presents a new automatic technique for the seg-mentation of the rib cage on CT images. Motivated by a usage scenario in the context of large, heterogeneous databases of CT-images, we introduce two shape descriptors to be used in conjunction with a Random Forests (RF) classifier. These de-scriptors were specifically designed to address the(More)
Many studies have reported multiple rib fractures sustained by an Out-of-Position (OOP) driver subjected to a frontal airbag deployment, but the injury mechanisms and thresholds remain unclear. Two successive phases occur during the bag deployment: punch-out loading of the thorax, followed by a membrane effect (Horsch et al. 1990). The aim of this study was(More)
Hexahedral elements with a single integration point have been the solid elements of choice to represent organs in human finite element models for impact. While those elements have been known to be efficient in terms of stability and computational cost, they are difficult to generate and meshing represents a significant part of a model development time. The(More)
We present here spectropolarimetric observations of the RS CVn system HR 1099 (V711 Tau) secured from 1998 February to 2002 January with the spectropolarime-ter MuSiCoS at the Télescope Bernard Lyot (Observatoire du Pic du Midi, France). We apply Zeeman-Doppler Imaging and reconstruct surface brightness and magnetic topologies of the K1 primary subgiant of(More)
OBJECTIVE Placenta increta or percreta is an uncommon pathology, sometimes associated with high maternal morbidity. Its prevalence increases proportionally to the number of cesarean sections. This study analyzed the changes of our management strategy to devise treatment guidelines for this uncommon disorder. MATERIALS AND METHODOLOGY Between 2005 and(More)
ESPaDOnS is a new-generation cross-dispersedéchelle spec-tropolarimeter, the commissioning phase of which is scheduled at the Canada-France-Hawaii Telescope (CFHT) for spring 2004. This instrument will provide full coverage of the optical domain (370 nm to 1,000 nm) in all polarization states (circular and linear) at a resolving power of about 70,000, with(More)