Clinical Focus on Prosodic, Discursive and Pragmatic Treatment for Right Hemisphere Damaged Adults: What's Right?

Researchers and clinicians acknowledge today that the contribution of both cerebral hemispheres is necessary to a full and adequate verbal communication. Indeed, it is estimated that at least 50% of right brain damaged individuals display impairments of prosodic, discourse, pragmatics and/or lexical semantics dimensions of communication. Since the 1990's, researchers have focused on the description and the assessment of these impairments and it is only recently that authors have shown interest in planning specific intervention approaches. However, therapists in rehabilitation settings still have very few available tools. This review of recent literature demonstrates that, even though theoretical knowledge needs further methodological investigation, intervention guidelines can be identified to target right hemisphere damage communication impairments in clinical practice. These principles can be incorporated by speech and language pathologists, in a structured intervention framework, aiming at fully addressing prosodic, discursive and pragmatic components of communication

High-order harmonic transient grating spectroscopy of SF6 molecular vibrations

special issue : Ultrafast electron and molecular dynamicsInternational audienceStrong field transient grating spectroscopy has shown to be a very versatile tool in time-resolved molecular spectroscopy. Here we use this technique to investigate the high-order harmonic generation from SF6 molecules vibrationally excited by impulsive stimulated Raman scattering. Transient grating spectroscopy enables us to reveal clear modulations of the harmonic emission. This heterodyne detection shows that the harmonic emission generated between 14 to 26 eV is mainly sensitive to two among the three active Raman modes in SF6, i.e. the strongest and fully symmetric nu 1-A1g mode (774 cm-1, 43 fs) and the slowest mode nu5-T2g (524 cm-1, 63 fs). A time-frequency analysis of the harmonic emission reveals additional dynamics: the strength and central frequency of the nu 1 mode oscillate with a frequency of 52 cm-1 (640 fs). This could be a signature of the vibration of dimers in the generating medium. Harmonic 11 shows a remarkable behavior, oscillating in opposite phase, both on the fast (774 cm-1) and slow (52 cm-1) timescales, which indicates a strong modulation of the recombination matrix element as a function of the nuclear geometry. These results demonstrate that the high sensitivity of high-order harmonic generation to molecularvibrations, associated to the high sensitivity of transient grating spectroscopy, make their combination a unique tool to probe vibrational dynamics

Studies of molecular dynamics probed by High Harmonic Generation

Grâce à ses propriétés (cohérence, brillance, durée), le rayonnement XUVfemtoseconde produit par génération d'harmoniques d'ordre élevé est utilisé comme unprocessus de sonde pour l'étude de dynamiques atomiques et moléculaires, avec une bonnerésolution spatiale et temporelle (femtoseconde voire attoseconde). Ainsi, des dynamiquesrotationnelles ont été résolues sur des petits systèmes moléculaires (N2, CO2). Les travauxde cette thèse ont consisté à étendre les méthodes de spectroscopie harmoniques et les appliquerà des systèmes moléculaires complexes d'intérêt femtochimique. Parmi elles, nousprésenterons la génération d'harmoniques à deux sources, le réseau transitoire d'excitationou encore la génération d'harmoniques à deux couleurs. Ces techniques nous ont permisde résoudre des dynamiques femtosecondes dans N2O4 et SF6. La HHG est aussi utiliséecomme source de rayonnement XUV, en jouant le rôle d'impulsion pompe lors d'expériencesde type pompe-sonde. Cette approche a été utilisée pour l'étude du dichroïsme circulairede photoélectrons de molécules chirales ionisées par un champ XUV harmonique de polarisationquasi circulaire. Nous nous attarderons à détailler la découverte de cette nouvellesource XUV femtoseconde de polarisation quasi circulaire.High harmonic generation (HHG) spectroscopy has proven to be a promisingtool (like probe in pump-probe experiments) in revealing the atomic and molecular dynamicswith the potential for subangstrom spatial resolution and subfemtosecond temporalresolution. Then, rotational dynamics have been resolved on small molecular systems (N2,CO2). This thesis looks to extending HHG spectroscopy methods to probe the structureand the dynamic of complex molecular systems. We will describe the two sources highharmonic generation, the transient grating of excitation and the two-color high harmonicgeneration. We enable to resolve the femtosecond nuclear dynamics in N2O4 and SF6. HHGis also used like a XUV radiation source, playing the role of pump pulse. This approach hasbeen used for the study of photoelectron circular dichroism. An XUV harmonic field witha quasi-circular polarization ionizes chiral molecules. In this manuscript, we will developthis new femtosecond XUV and quasi circular polarization radiation

Étude des dynamiques moléculaires sondées par génération d'harmoniques d'ordre élevé

High harmonic generation (HHG) spectroscopy has proven to be a promisingtool (like probe in pump-probe experiments) in revealing the atomic and molecular dynamicswith the potential for subangstrom spatial resolution and subfemtosecond temporalresolution. Then, rotational dynamics have been resolved on small molecular systems (N2,CO2). This thesis looks to extending HHG spectroscopy methods to probe the structureand the dynamic of complex molecular systems. We will describe the two sources highharmonic generation, the transient grating of excitation and the two-color high harmonicgeneration. We enable to resolve the femtosecond nuclear dynamics in N2O4 and SF6. HHGis also used like a XUV radiation source, playing the role of pump pulse. This approach hasbeen used for the study of photoelectron circular dichroism. An XUV harmonic field witha quasi-circular polarization ionizes chiral molecules. In this manuscript, we will developthis new femtosecond XUV and quasi circular polarization radiation.Grâce à ses propriétés (cohérence, brillance, durée), le rayonnement XUVfemtoseconde produit par génération d'harmoniques d'ordre élevé est utilisé comme unprocessus de sonde pour l'étude de dynamiques atomiques et moléculaires, avec une bonnerésolution spatiale et temporelle (femtoseconde voire attoseconde). Ainsi, des dynamiquesrotationnelles ont été résolues sur des petits systèmes moléculaires (N2, CO2). Les travauxde cette thèse ont consisté à étendre les méthodes de spectroscopie harmoniques et les appliquerà des systèmes moléculaires complexes d'intérêt femtochimique. Parmi elles, nousprésenterons la génération d'harmoniques à deux sources, le réseau transitoire d'excitationou encore la génération d'harmoniques à deux couleurs. Ces techniques nous ont permisde résoudre des dynamiques femtosecondes dans N2O4 et SF6. La HHG est aussi utiliséecomme source de rayonnement XUV, en jouant le rôle d'impulsion pompe lors d'expériencesde type pompe-sonde. Cette approche a été utilisée pour l'étude du dichroïsme circulairede photoélectrons de molécules chirales ionisées par un champ XUV harmonique de polarisationquasi circulaire. Nous nous attarderons à détailler la découverte de cette nouvellesource XUV femtoseconde de polarisation quasi circulaire

Clinical focus on prosodic, discursive and pragmatic treatment for right hemisphere damaged adults: what's right? Rehabilitation Research and Practice

Researchers and clinicians acknowledge today that the contribution of both cerebral hemispheres is necessary to a full and adequate verbal communication. Indeed, it is estimated that at least 50% of right brain damaged individuals display impairments of prosodic, discourse, pragmatics and/or lexical semantics dimensions of communication. Since the 1990's, researchers have focused on the description and the assessment of these impairments and it is only recently that authors have shown interest in planning specific intervention approaches. However, therapists in rehabilitation settings still have very few available tools. This review of recent literature demonstrates that, even though theoretical knowledge needs further methodological investigation, intervention guidelines can be identified to target right hemisphere damage communication impairments in clinical practice. These principles can be incorporated by speech and language pathologists, in a structured intervention framework, aiming at fully addressing prosodic, discursive and pragmatic components of communication

Combined high-harmonic interferometries for vectorial spectroscopy

We present a new method to characterize transverse vectorial light produced by high-harmonic generation (HHG). The incoherent sum of the two components of the electric field is measured using a bi-dimensional transient grating while one of the components is simultaneously characterized using two-source interferometry. The combination of these two interferometric setups enables the amplitude and phase measurement of the two vectorial components of the extreme ultraviolet radiation. We demonstrate the potential of this technique in the case of HHG in aligned nitrogen, revealing the vectorial properties of harmonics 9–17 of a Ti:sapphire laser

Quantum-path resolved attosecond high-harmonic spectroscopy

International audienceStrong-field ionization of molecules releases electrons which can be accelerated and driven back to recombine with their parent ion, emitting high-order harmonics. This ionization also initiates attosecond electronic and vibrational dynamics in the ion, evolving during the electron travel in the continuum. Revealing this subcycle dynamics from the emitted radiation usually requires advanced theoretical modeling. We show that this can be avoided by resolving the emission from two families of electronic quantum paths in the generation process. The corresponding electrons have the same kinetic energy, and thus the same structural sensitivity, but differ by the travel time between ionization and recombination—the pump-probe delay in this attosecond self-probing scheme. We measure the harmonic amplitude and phase in aligned CO$_2$ and N$_2$ molecules and observe a strong influence of laser-induced dynamics on two characteristic spectroscopic features: a shape resonance and multichannel interference. This quantum-path resolved spectroscopy thus opens wide prospects for the investigation of ultrafast ionic dynamics, such as charge migration

Changes in brain perfusion in successive arterial spin labelling MRI scans in neonates with hypoxic-ischemic encephalopathy

International audienceThis article proposes an innovative processing pipeline for morphological and ASL data suited to neonates that enable automated segmentation to obtain CBF values over ROIs. We evaluate CBF on two successive scans within the first 15 days of life in the same subjects. ASL imaging in asphyxiated neonates seems more relevant when used relatively early, in the first days of life. The correlation of intra-subject changes in cerebral perfusion between early and late MRI with neurodevelopmental outcome warrants investigation in a larger cohort, to determine whether the CBF pattern change can provide prognostic information beyond that provided by visible structural abnormalities on conventional MRI

Toward Femtochemistry with Circular Polarized Pulses

International audienc