[en] This paper reports on one hundred fifty patients with suscepted acoustic neurinoma examined with a 1.5-T MR imaging. All patients were injected with Gd-DTPA or Gd-DOTA, and T1-weighted spin-echo sequences were obtained. Thirty postoperative patients underwent pre- and post contrast MR imaging. Forty-five patients had normal findings. In 88 patients, one or two neurinomas were detected. Eighteen cases were equivocal. In seven cases, contrast enhancement was due to other tumors (five meningiomas, one arachnoidocele, one intracanalicular hemangioma). In six other cases, misinterpretation resulted from partial volume effects with the bone marrow of the petrous bone (four cases), or thrombosed vessels in the prepontine cistern (one case). In patients, previously operated on, increased signal was due to tumor recurrence (12 of 30 cases) but also to the presence of a postoperative fatty graft (seven of 30) or an inflammatory enhancement of the canalicular meninges (five of 30). Most of the diagnostic problems may be obviated with use of precontrast MR imaging, multidimensional 3-mm sections, and fast imaging

[en] The expert system developed for assisting the fuel maintenance operations in fast neutron reactors is presented. The expert system, implemented in the Phenix reactor, performs the analysis and interpretation of data provided by the control systems. Two types of assistance are possible: a system for interpreting the data from ultrasonic images (VISUS-PLUS) and another for the visualisation of the effort involved in the removal and replacement of the fuel. The experiment proved that the maintenance assistance improves the conditions of the reactor operation

[en] Radiative corrections to virtual Compton scattering are calculated for the first time at the first order in α. We use the dimensional regularization scheme to treat both Ultra-Violet and Indra-Red divergences. After the compensation of divergences, the expression of the correction contains analytical terms and a numerical term which has to be computed. For a scattered photon of centre of mass energy q'= 45 MeV, a preliminary result of the comparison between theory and experimental data is presented taking into account only analytical terms. (authors)

[en] We measured the angular dependence of the three recoil proton polarization components in two-body photodisintegration of the deuteron at a photon energy of 2 GeV. These new data provide a benchmark for calculations based on quantum chromodynamics. Two of the five existing models have made predictions of polarization observables. Both explain the longitudinal polarization transfer satisfactorily.. Transverse polarizations are not well described, but suggest isovector dominance

[en] We report the most precise measurement to date of a parity-violating asymmetry in elastic electron-proton scattering. The measurement was carried out with a beam energy of 3.03 GeV and a scattering angle <θ_lab> = 6.0 degrees, with the result A_PV = -1.14 ± 0.24 (stat) ± 0.06 (syst) parts per million. From this we extract, at Q² = 0.099 GeV², the strange form factor combination G_E^s + 0.080 G_M^s = 0.030 ± 0.025 (stat) ± 0.006 (syst) ± 0.012 (FF) where the first two errors are experimental and the last error is due to the uncertainty in the neutron electromagnetic form factor. The measurement significantly improves existing constraints on G_E^s and G_M^s at Q² ∼0.1 GeV². A consistent picture emerges from all measurements at this Q². A combined fit shows that G_E^s is consistent with zero while G_M^s prefers positive values though G_E^s = G_M^s = 0 is compatible with the data at 95% C.L