Intensity Correlation between Observations at Differrent Wavelengths for Mkn 501 in 1997

The CAT imaging telescope on the site of the former solar plant Th'emis in southern France observed gamma-rays from the BL Lac object Mkn501 above 250 GeV for more than 60 usable hours on-source from March to October 1997. This source was in a state of high activity during all this period. By studying the correlation between the photons of different energies detected by the CAT imaging telescope and by the ASM/RXTE experiment (1.3-12.0 keV) on board the Rossi X-Ray Timing Explorer, we may constrain the mechanisms which could lead to the emission of these photons.Comment: Proceedings of the 19th Texas Symposium. 8 pages, 7 figure

Matrix probing: a randomized preconditioner for the wave-equation Hessian

This paper considers the problem of approximating the inverse of the wave-equation Hessian, also called normal operator, in seismology and other types of wave-based imaging. An expansion scheme for the pseudodifferential symbol of the inverse Hessian is set up. The coefficients in this expansion are found via least-squares fitting from a certain number of applications of the normal operator on adequate randomized trial functions built in curvelet space. It is found that the number of parameters that can be fitted increases with the amount of information present in the trial functions, with high probability. Once an approximate inverse Hessian is available, application to an image of the model can be done in very low complexity. Numerical experiments show that randomized operator fitting offers a compelling preconditioner for the linearized seismic inversion problem.Comment: 21 pages, 6 figure

Identification des paramètres de coupe en percage vibratoire

sans résum

Neuropathy After Herniorrhaphy: Indication for Surgical Treatment and Outcome

Background: Chronic neuropathy after hernia repair is a neglected problem as very few patients are referred for surgical treatment. The aim of the present study was to assess the outcome of standardized surgical revision for neuropathic pain after hernia repair. Methods: In a prospective cohort study we evaluated all patients admitted to our tertiary referral center for surgical treatment of persistent neuropathic pain after primary herniorrhaphy between 2001 and 2006. Diagnosis of neuropathic pain was based on clinical findings and a positive Tinel's sign. Postoperative pain was evaluated by a visual analogue scale (VAS) and a pain questionnaire up to 12months after revision surgery. Results: Forty-three consecutive patients (39 male, median age 35years) underwent surgical revision, mesh removal, and radical neurectomy. The median operative time was 58min (range: 45-95min). Histological examination revealed nerve entrapment, complete transection, or traumatic neuroma in all patients. The ilioinguinal nerve was affected in 35 patients (81%); the iliohypogastric nerve, in 10 patients (23%). Overall pain (median VAS) decreased permanently after surgery within a follow-up period of 12months (preoperative 74 [range: 53-87] months versus 0 [range: 0-34] months; p<0.0001). Conclusions: The results of this cohort study suggest that surgical mesh removal with ilioinguinal and iliohypogastric neurectomy is a successful treatment in patients with neuropathic pain after hernia repai

A PIONIER View on Mass-Transferring Red Giants

Symbiotic stars display absorption lines of a cool red giant together with emission lines of a nebula ionized by a hotter star, indicative of an active binary star system in which mass transfer is occurring. PIONIER at the VLT has been used to combine the light of four telescopes at a time to study in unprecedented detail how mass is transferred in symbiotic stars. The results of a mini-survey of symbiotic stars with PIONIER are summarised and some tentative general results about the role of Roche lobe overflow are presented.Comment: Report for the ESO Messenger June issu