Low mass dimuon production in proton and ion induced interactions at SPS

The low mass dimuon spectra collected in p-U collisions by the NA38 experiment significantly exceeds the total cross section expected from previous analysis, done by other experiments. The `excess' events have a harder \pt\ distribution than the muon pairs from $\eta$ and $\omega$ Dalitz decays, expected to dominate the mass window 0.4--0.65~GeV/$c^2$. We conjecture that the excess events might be due to \qqbar\ annihilations, negligible at low \pt\ but made visible by the \mt\ cut applied in the NA38 data. Taking this assumption to parametrise the p-U spectra, we proceed with the analysis of the S-Cu, S-U and Pb-Pb data, collected by the NA38 and NA50 experiments, where we find that the measured mass spectra does not seem to exceed the expected low mass `cocktail' by more than 20\,\%

Augmentation de contraste « adaptative » suivant les niveaux de gris des contours

Two different locally adaptative contrast enhancement techniques with no information loss are described. The first one uses a new definition of a pixel contrast based on the position of its grey level relative to the average grey level of the surrounding countours. Following the same principle the second technique refers to the contrast as a linear function of the difference between the grey level of a pixel and the grey level of the surrounding countours. Both treatments have been used in image analysis to follow the density variations of supercritical xenon in microgravity conditions.Nous présenterons ici deux méthodes d'augmentation de contraste localement « adaptatives » sans perte d'informations. La première consiste à définir différemment une fonction de contraste sur un pixel suivant la position de son niveau de gris par rapport à celui de la moyenne des contours du voisinage. La deuxième reprend le même principe en s'attachant à la linéarité de la définition du contraste par rapport à l'écart entre le niveau de gris du pixel traité et le niveau de gris des contours. Ce traitement intervient dans une analyse d'image d'une expérience de variation de densité en microgravité sur du xénon supercritique

Augmentation de contraste « adaptative » suivant les niveaux de gris des contours

Nous présenterons ici deux méthodes d'augmentation de contraste localement « adaptatives » sans perte d'informations. La première consiste à définir différemment une fonction de contraste sur un pixel suivant la position de son niveau de gris par rapport à celui de la moyenne des contours du voisinage. La deuxième reprend le même principe en s'attachant à la linéarité de la définition du contraste par rapport à l'écart entre le niveau de gris du pixel traité et le niveau de gris des contours. Ce traitement intervient dans une analyse d'image d'une expérience de variation de densité en microgravité sur du xénon supercritique

Electron transfer reactions between excited atoms and molecules

Electron tranfer reactions have been extensively studied for atoms in ground state colliding with molecules. On the contrary, few experiments have been perfomed for atoms excited above the first resonance states and it has been supposed by some authors that above a given degree of excitation, electron transfer becomes negligeable. By using a simple Landau-Zener model and a LCAO calculation of the coupling matrix element between ionic and covalent states for excited atoms and molecules with small electron affinities, we conclude that there is no limit to the electron transfer, in agreement with the experimental observation of ion pair formation for Rydberg atoms colliding with given molecules such as SF6

Mössbauer study and molecular orbital calculations on the organo-iron (I, II) electron reservoir sandwiches CpFen+ (η6-C6(CH3)6) (n = 0,1) and related CpFe (cyclohexadienyl) complexes

The paramagnetic Fe(I) electron reservoir sandwich η5-C 5H5Fe(I) η6-C6(Me)6, its oxidized mono-cationic diamagnetic form and related diamagnetic η5-C5H 5Fe (cyclohexadienyl) complexes have been studied by Mössbauer spectroscopy on powders and aligned crystals. Spectra under high magnetic field were recorded for powders. On the basis of X-ray data I.E.H.T. MO calculations were performed and gave results in good agreement with experimental data at room temperature and liquid helium temperature. The relaxation of molecular orbitals associated to the electronic reduction from II to I was found to be negligible, which enables to consider a Fe(I) complex as a superposition of a Fe(II) complex and one electron. This electron is occupying the doubly degenerate e *1 orbital and has a very strong metallic character (83 %).Le sandwich paramagnétique réservoir d'électrons η5-C 5H5Fe(I) η6-C6(CH3) 6 ainsi que sa forme diamagnétique monocationique oxydée et les complexes η 5-C5H5Fe (cyclohexadienyl) correspondants ont été étudiés par spectrométrie Mössbauer sur des poudres et des monocristaux. Les spectres sous champ magnétique intense ont été enregistrés sur des poudres. A partir des données de rayons X, on a fait des calculs d'orbitales moléculaires I.E.H.T. qui ont donné des résultats en bon accord avec les données expérimentales à température ambiante et à 4,2 K. Les calculs d'OM montrent que la relaxation des orbitales moléculaires associée à la réduction électronique de II à I est négligeable ce qui permet de considérer un complexe de fer(I) comme la superposition d'un complexe de fer(II) et d'un électron. Cet électron occupe l'orbitale e*1 doublement dégénérée et a un très fort caractère métallique (83 %)

Identification et sélection chez les ovins et caprins à partir de la situation française

Session 6 *INRA SAGA 31326 Castanet-Tolosan (FRA) Diffusion du document : INRA SAGA 31326 Castanet-Tolosan (FRA)National audienc

MÖSSBAUER SPECTROSCOPIC STUDY OF 19 ELECTRON ORGANOMETALLIC PARAMAGNETIC SANDWICHES n5-C5R5Fe(I)n6-C6R'6.

No abstract availabl

Balance Sheet of Screening for Diabetic Retinopathy With a Mobile Non-Mydriatic Digital Camera in Burgundy, France

Purpose: To assess the economic balance-sheet of screening for diabetic retinopathy (DR) with a mobile non-mydriatic digital camera in Burgundy, France, in a public health and economic perspective.Methods: The 72 lowest medicalised areas of Burgundy were visited. Retinal images were obtained with a non-mydriatic camera. To construct an economic model, we used available data on the prevalence of diabetes in Burgundy, the efficiency of the screening, the number of screened DR, blindness probability according to DR grading, the efficiency of laser therapy, the diabetic characteristics (gender, age, income, professional status and life expectancy) and medical costs induced by our campaign.Results: 3363 diabetics (mean age: 70±11 years) have had an ocular examination for more than 2 years and only 2547 patients were declared eligible (previous medical examination by an ophthalmologist more than 2 years and no RD previously known according to the patient). Among the 3363 patients, only 3 treatable DR and 25 macular oedemas were found. Among eligible patients, neither treatable DR nor macular oedema was found. If we consider only the financial analysis, results showed a cost overrun per patient from Social Security perspective (cost: 97±248 euros; saving i.e. avoided contributions: 49±580 euros) and from societal perspective (cost: 112±57 euros; saving, i.e. avoided loss of income: 6±177 euros).Conclusions: Our study showed the unfavourable balance-sheet of our DR screening sessions. However these results need to be considered in an overall improvement of the quality of life

Modélisation numérique et expérimentale du deferlement

Présentation des activités liés au contrat passé avec le PATO