Search

La création du test de reconnaissance d’images naturelles FIBULIGO s’est inscrit dans une pratique pluridisciplinaire vécue au sein des Instituts d’Éducation Motrice de l’ARAHM (Strasbourg). Elle répond à un besoin d’outils complémentaires dans le dépistage et la caractérisation des déficiences visuelles d’origine cérébrale mais aussi à un besoin d’une meilleure connaissance du développement de la reconnaissance visuelle chez l’enfant.

La mise en évidence de difficultés dans les apprentissages chez l’enfant, nécessite d’analyser les différentes fonctions visuelles afin de détecter les troubles associés, en particulier, les difficultés dans la reconnaissance d’images. Nous avons créé un test de reconnaissance d’images naturelles, nommé FIBULIGO, qui s’inscrit dans une pratique pluridisciplinaire et tient compte des connaissances actuelles dans les analyses cérébrales du message visuel. FIBULIGO se positionne comme un outil complémentaire dans le dépistage et la caractérisation des déficiences visuelles d’origine cérébrale au niveau des analyses perceptives chez des enfants de 4 à 10 ans.

Afin de susciter un intérêt visuel pour l’image, support indispensable aux prérequis des apprentissages scolaires, nous avons proposé un travail sur les ombres chinoises à cinq enfants cérébrolésés présentant un retard de développement psychomoteur important et des troubles neurovisuels. Dans une première partie, les perceptions visuelles sont sollicitées par des couleurs, des formes géométriques élémentaires puis par des silhouettes simples projetées sur un écran. Dans un second temps, les structurations spatiales et temporelles, la proprioception et le schéma corporel sont travaillés en créant des ombres avec le corps sur un écran. Nous avons observé plusieurs types d’évolutions, visuelles et comportementales : une augmentation de l’intérêt pour l’image tant par sa création que par son observation, une diminution de la distractibilité et des relations sociales plus manifestes. Cette expérience thérapeutique et éducative menée sur une année témoigne de l’importance d’une prise en charge pluridisciplinaire tant par la mise en commun des savoirs, que par la confrontation des objectifs propres à chaque professionnel pour un accompagnement holistique du jeune enfant cérébrolésé dans l’appréhension de l’image.

Abstract:: Final states indicating the presence in the reaction of three-body fragmentation processes has been observed in 32S+59Co and 32S+63Cu dissipative collisions at 5.6 A · MeV. Besides the already observed sequential binary process, data analysis reveals the presence of prompt ternary break-up of the composite system. Indications on the system configuration at the scission have been deduced by analyzing the event shape in the momentum phase space. The decay appears to occur in a collinear configuration, one of the produced fragments originating from the neck which connects the other two. In spite of the large energy dissipation, structure effects in the charge partition seem to affect part of events.

Charged pions are measured with the 4π detector FOPIat GSIusing the Au on Au reaction at 1.06 AGeV bombarding energy. The pion multiplicities ngpincrease with the number of participants Apart. The average pion multiplicities per participant are #### and #### These values are only half as large as extrapolated from the low-mass systems studied by Harris et al. The ratio #### increases with Apartand decreases with the pion kinetic energies. The pion kinetic energy spectra have concave shapes, their parametrization in terms of thermal Boltzmann distributions yields a low (Tl,π) and high (Th,π) temperature which change with the cm emission angle Θ of the pions. In the angular range 45dg < Θ< 135° the low temperature < Tl,π−> is larger than < Tl,π+>, the high temperatures < Th,π−>, < Th,π+> are, within experimental uncertainties, the same. The inclusive polar angular distributions of pions are anisotropic, dσ/dΩincreases for forward and backward angles. The forward — backward enhancements are independent of the pion kinetic energies or the number of participants. In addition to the preferred forward — backward emission, also the enhanced emission into the transverse direction Θ =90° is observed for pions with high energies or for pions from near-central collisions. These observations and the shape of the rapidity spectra suggest that pions, emitted from the central rapidity region, are partly rescattered by spectator matter. The strength of the rescattering process depends only weakly on the number of participants. The experimental data are compared to the results of IQMD/GEANTcalculations using momentum dependent NNinteractions and a hard equation of state. The calculated pion multiplicities are approximately 50% larger than experimentally determined; the existence of secondary pion sources is reproduced by the calculation, but their predicted strengths are larger than experimentally observed.

Abstract:: We studied the sequential binary decay of the systems 32S+45Sc, 76Ge, 89Y, 59Co, 63Cu and 19F+63Cu induced by collisions at ≃6 MeV·A. The two stages of the process have reaction-times compatible with the dynamics of different mechanisms. The study of the excitation energy partition shows that the reaction mechanism of the first step has influence on the de-excitation of the primary fragments producing two decay components which have different time scale.

Protons, deuterons, tritons,a-particles and Li have been studied in coincidence with evaporation residues produced at low impact parameter for the40Ar(1100 MeV)+13C reaction. Experimental characteristics of the light particle — heavy residue correlations, and among them an effect of left-right asymmetry, are analyzed and discussed in some detail on the basis of Monte Carlo simulations. This reaction appears to be governed by an incomplete fusion process. Due to transverse emission of preequilibrium particles, the compound nuclei associated with light-particle-evaporation-residue coincidence events recoil at a non-zero degree lab. angle with some dispersion around this direction. When these effects are introduced into statistical decay calculations, it is then possible to reproduce various experimental results and to understand features like the asymmetry effect. Discrimination of light particles of preequilibrium and of evaporative origin appears possible.

In an attempt to separate preequilibrium and thermalised emissions of light particles in low impact parameter heavy-ion collisions, the40Ar+24Mg reaction has been studied at 27.5 MeV/nucleon. Exclusive measurements have permitted us to examine, in some detail, heavy fragments and charged particles (p, d, t,a-particle). The fragments recognized as evaporation residues have been selected and, due to inverse kinematic conditions, the related preequilibrium and statistical emissions of light particles resulting from incomplete fusion reaction appear to be distinguishable to a fair extent. This separation is fully supported by Monte Carlo calculations. Some experimental characteristics of the light particles have been examined and compared to the predictions of dynamical calculations. These calculations, associating a preequilibrium (interpreted as prompt emitted particles) model with a statistical-decay model, follow the evolution of the collision from the point of contact between the projectile and the target to the final evaporation-residue formation on an event by event basis. The predictions of these calculations have been compared to experimental data and satisfactory agreement is achieved for fragment-mass distribution, proton-energy spectra, and proton-angular distribution.

The projectile-like fragments emitted in the40Ar +68Zn reaction performed at 14.6, 19.6, 27.6 and 35 MeV/nucleon are studied. Their energy spectra and angular distributions have been measured. Velocities, widths of the linear momentum distributions and cross sections have been deduced. The results are discussedi) in terms of transfer of a few nucleons and analysed with a diffractional model. They are consistent, for stripping reactions, with a direct transfer of nucleons and a target excitation yielding multiparticlemultihole configurations,ii) In terms of projectile fragmentation-like process with a modified abrasion model taking into account the energy separation of the participant nucleons. The projectile fragmentation-like process appears above 20 MeV/nucleon and strongly competes with transfer of nucleons at 35 MeV/nucleon. The evolution of the mechanisms with incident energy is discussed on the basis of the reduced widths of the linear momentum distributions and on those of velocities and cross sections.

The light charged particles emitted in the40Ar+68Zn reaction performed at 14.6, 19.6 and 35 MeV/nucleon have been studied inclusively. The energy spectra have been analysed in terms of preequilibrium emission, moving source and coalescence models. A complete coherence between the present data and those obtained separately from heavy fragment studies is achieved. These data are consistent with the onset of projectile fragmentation between 20 and 35 MeV/nucleon correlated with the formation of a highly excited region of the nuclear system inducing light particle emission. The other sources of light particles can be interpreted as statistical and sequential decay of the quasi projectile.

The isotope distributions, momentum width distributions, and velocities of the projectile-like fragments in the40Ar on68Zn reaction have been measured at 27.6 MeV/nucleon incident energy. The results show the existence of a fragmentation process well described in the framework of the high energy fragmentation model. However, important contributions from direct nucleon transfer and damped collisions are present.

Using the FOPI facility at GSI, charged particles (1 ≤Z≤6) produced in the Au(150 A MeV)+Au reaction have been measured at laboratory angles 1.20< Θlab<300. Highly central collisions have been selected with two criteria, both dealing with the longitudinal and transverse degrees of freedom of the reaction. The relevance of this selection method is supported by QMD calculations which indicate that such criteria are able to select mean impact parameters less than 2 fm. Bias effects introduced by the criteria have been evaluated. The centre-of-mass polar angle distributions of low energy clusters emitted in these central collisions, have been extracted: the intensity ratio deduced for a transverse to longitudinal emission is found to be R= 1.4−0.4+0.2. Model comparisons using QMD are presented. The value of R appears to depend sensitively on the nucleon-nucleon cross section, σnn. Within this model, a value of σ=25+ - 5 mb is derived.

Particles with strange quark content produced in the system 1.93A·GeV58Ni on58Ni have been investigated at GSI Darmstadt with the FOPI detector system. The correlation of these produced particles was analyzed with respect to the reaction plane.? baryons exhibit a very pronounced sideward flow pattern which is qualitatively similar to the proton flow. However, the kaon (K+,Ks0) flow patterns are significantly different from that of the protons, and their form may be useful to restrict theoretical models on the form of the kaon potential in the nuclear medium.

The study of three-body channels in ³²S+⁴⁵Sc, ⁷⁶Ge, ⁸⁹Y, ⁵⁹Co, ⁶³Cu and ¹⁹F+⁶³Cu reactions around 6 MeV·A evidenced the presence of two-step binary processes even at low bombarding energy. A fairly constant charge amount is found to be transferred from target to projectile, regardless of the system total mass and mass asymmetry.

The study of three-body channels in32S+45Sc,76Ge,89Y,59Co,63Cu and19F+63Cu reactions around 6 MeV·Aevidenced the presence of two-step binary processes even at low bombarding energy. A fairly constant charge amount is found to be transferred from target to projectile, regardless of the system total mass and mass asymmetry.

The article presents the poem "The Spider's Sorrow," by Nathaniel Fintz. First Line: A tangled mess of copper fiber; Last Line: iMac?

The article presents the poem "Manhattan," by Nathaniel Fintz. First Line: Bright-eyed behemoths; Last Line: Manhattan.