Sur la dimension de certaines variétés de Kisin : le cas de la restriction des scalaires de GLd

Given a p-torsion representation of the absolute Galois group of a p-adic field, M. Kisin defines a moduli space, which was named Kisin variety afterwards by G. Pappas and M. Rapoport. These varieties were first introduced in order to prove several modularity results on Galois representations. They were also used for constructing certain Galois deformation rings and computing some of them. Besides, they were involved in a recent work aiming at defining an algebraic structure on the stack of torsion Galois representations. It turns out that these varieties are formally similar to affine Deligne-Lusztig varieties. In particular their definition extends to the framework of reductive groups. In this thesis, we study the dimension of some Kisin varieties corresponding to the scalar restriction of the general linear group GLd. Inspired by methods coming from Deligne-Lusztig theory and following works by E. Viehmann and X. Caruso, we define a stratification on the given Kisin variety. Then we bound from below and from above the dimension of the strata, and we address the problem of maximizing the dimension over all strata. This allows us to derive the announced bounds on the dimension. As for affine Deligne-Lusztig varieties, the sum of the positive roots appears in the bounds.A une représentation de p-torsion du groupe de Galois absolu d'un corps p-adique, M. Kisin associe un espace de modules, appelé par la suite variété de Kisin par G. Pappas et M. Rapoport. Ces variétés ont été introduites afin de démontrer plusieurs résultats de modularité sur les représentations galoisiennes. Elles se sont révélées utiles également pour construire certains anneaux de déformations voire les calculer. Plus récemment elles ont été utilisées pour munir le champ des représentations galoisiennes de torsion d'une structure algébrique. Par ailleurs ces variétés ressemblent formellement aux variétés de Deligne-Lusztig affines. En particulier leur définition s'étend dans le cadre de la théorie des groupes réductifs. Dans cette thèse, nous étudions la dimension de certaines variétés de Kisin dans le cas de la restriction des scalaires à la Weil du groupe linéaire général GLd. En nous basant sur des méthodes issues du cadre Deligne-Lusztig et en suivant les travaux de E. Viehmann et X. Caruso, nous définissons une stratification de la variété de Kisin. Nous encadrons ensuite la dimension des strates, puis étudions le problème de la maximisation de la dimension sur l'ensemble des strates. Cela permet de démontrer des encadrements pour la dimension des variétés de Kisin considérées. Comme dans le cas des variétés de Deligne-Lusztig affines, la somme des racines positives intervient dans l'encadrement de la dimension

Psychoacoustic investigation of auditory cues involved in human underwater sound localization

International audienceTheoretical arguments about underwater sound localization predict that auditory cuesused in air are impaired in water. However, long term acclimatization could emerge due toexposure to the environment. We have compared localization abilities of expert and novicedivers. The localization task was conducted for 8 azimuthal sound positions and 8 signals(0.4, 1, 2, 4, 6, 8, 10 kHz, white-noise). Results indicate that localization was better forexperts: they made more correct localizations and their directional response distribution wasless dispersed. These results demonstrate long term acclimatization in the processing oflocalization cues under water, particularly of interaural cues

Investigation of auditory cues involved in human underwater sound localization

International audienceTheoretical arguments about underwater sound localization predict that auditory cues used in air areimpaired in water, resulting in a theoretical inability to locate sounds under water. An azimuth identification task wasconducted under water for 8 positions (0°, 45°, 90°, 135°, 180°, 225°, 270°, 315°) and 3 signals (400 Hz sine, 6 kHzsine, white-noise). Results demonstrate that localization was possible, at least for lateral positions, indicating thatinteraural cues are processed. The absence of spectral pinna cues may explain a large front/back confusion pattern

Absorption and Fluorescence Signatures of 1,2,3-Triazole Based Regioisomers : Challenging Compounds for TD-DFT

International audienceIn the continuous quest for improving TD-DFT methodologies as a tool to predict the photophysical features of solvated chro- mophores, we herein investigate two model regioisomers based on the 1,2,3-triazole moiety. Starting from their experimental absorption and emission spectra, key energy differences highlighting the main trends between the two isomers are extracted and used to gauge the accuracy of several levels of theory. RI-CC2 and EOM-CCSD calculations allow us to ascertain that the low energy spectra is not linked to double excitations. In vacuum, neither these methods nor any of the implemented TD-DFT levels of theory, ranging from global hybrids (PBE0, B3LYP) to range-separated functionals without (CAM-B3LYP, ωB97X) or with dispersion corrections (ωB97X-D), is able to capture the key features that differentiate the two chromophores. Accounting for solvent within a specific PCM model allows to recover experimental trends, but the dramatic changes occurring when moving from toluene to THF and/or for different PCM approaches (LR, cLR, SS) suggest that this agreement is probably fortuitous. Even so the ωB97X-D functional combined to the SS-PCM scheme leads to quantitative agreement with experiment, TD-DFT results obtained for 1,2,3-triazole based chromophores need to be treated with caution. We also show that the SS-PCM approach may be useful to test current and novel exchange-correlation functionals against the charge transfer failure

Auditory time-frequency masking: psychoacoustical data and application to audio representations

International audienceIn this paper, the results of psychoacoustical experiments on auditory time-frequency (TF) masking using stimuli (masker and target) with maximal concentration in the TF plane are presented. The target was shifted either along the time axis, the frequency axis, or both relative to the masker. The results show that a simple superposition of spectral and temporal masking functions does not provide an accurate representa- tion of the measured TF masking function. This confirms the inaccuracy of simple models of TF masking currently implemented in some percep- tual audio codecs. In the context of audio signal processing, the present results constitute a crucial basis for the prediction of auditory masking in the TF representations of sounds. An algorithm that removes the in- audible components in the wavelet transform of a sound while causing no audible difference to the original sound after re-synthesis is proposed. Preliminary results are promising, although further development is re- quired

Cyclometalated platinum(II) with ethynyl-linked azobenzene ligands: an original switching mode.

International audienceThe photophysical properties of 6-phenyl-2,2'-bipyridyl platinum(ii) complexes bearing different σ-alkynyl-linked azobenzene ancillary ligands were investigated. These complexes exhibited strong, broad, structureless charge-transfer bands in the visible region, which were red-shifted when the electron-donating ability of the para substituent on the azo-acetylide ligand increased. When excited at the charge-transfer absorption band, the complexes exhibited weak green emission, which was assigned to a triplet metal-to-ligand charge transfer/interligand charge transfer emission ((3)MLCT/(3)L'LCT). The presence of an amino substituent in the azobenzene moiety opened the possibility of protonation, which led to the formation of an azonium based derivative and resulted in drastic perturbations of the molecular orbitals and photophysical properties of the Pt-acetylide complex. These studies are fully supported by DFT and TD-DFT calculations

Local Health Departments' Partners and Challenges in Electronic Exchange of Health Information

BACKGROUND: Unprecedented amounts of data are produced by the health care and other sectors, presenting opportunities for local health departments (LHDs) to access these data. LHDs will need to participate in health information exchange (HIE) with a number of partners in order to benefit from these data resources. LHDs' participation in HIEs with specific partners has not been studied. OBJECTIVES: To describe the level of and challenges in LHD participation in HIE with other partners, and variation by LHD population size and governance type. DATA AND METHODS: This research uses data from the 2015 Informatics Capacity and Needs Assessment Survey, with a target population of all LHDs in the United States. A representative sample of 650 LHDs was drawn using a stratified random sampling design. A total of 324 completed responses were received with a 50% response rate. Survey data were cleaned, and bivariate comparisons were conducted using χ and Somer's D. RESULTS: Substantial variation existed in LHDs' participation in HIE by type of exchange partner. Although 71% participated in HIE with the state departments of health, only 12% with jail/correctional health, 14% with health or county-based purchasing plans, and 15% with home health agencies. Compared with large LHDs (jurisdiction populations of ≥500 000), smaller LHDs were more likely to participate in HIE with state departments of health, but less likely with other exchange partners. The challenges to HIE participation were technological, and organizational/interorganizational in nature and variation existed by LHDs' population size and governance structure with respect to state authority. CONCLUSIONS: Local public health agencies more commonly participate in HIE with some partners, but may need to improve HIE with many others. National strategies targeting an increase in HIE of LHDs may use our findings to focus those initiatives

The Potomac Ploy: George Washington’s Secret Scheme That Shaped the Nation’s Capital

For over 200 years, historians have glossed over blemishes on George Washington’s reputation, transforming the president into an almost mythological figure of the United States’ national identity. This paper brings into focus one of the more overlooked narratives about the president, revealing that his choice of Washington DC and the Potomac River as the location for the national capital was driven by financial self-interest and not by a prescient vision of future national unity. Overwhelming evidence demonstrates that Washington knew the Potomac River could not serve as a national waterway; he was well aware of impassible rapids, sudden drops that totaled 874 feet, and large mountains that completely obstructed the river. Despite this, Washington continued to pursue development along the Potomac for personal financial gain. By the early 1790s, the country had sent thousands of dollars to his private river company, promoted settlement in areas near Washington’s land holdings, and begun the creation of a major city within walking distance of Mount Vernon. The revelation of Washington’s true motivations for choosing this location for the national capital complicates the myth of this founding father as the epitome of a perfect leader. It calls into question the legitimacy of the political, racial, and economic hierarchies that have transformed a self-interested slaveholder into a centerpiece of modern democracy

Photoisomerisation in Aminoazobenzene-Substituted Ruthenium(II) Tris(bipyridine) Complexes: Influence of the Conjugation Pathway.

International audienceTransition-metal complexes containing stimuli-responsive systems are attractive for applications in optical devices, photonic memory, photosensing, as well as luminescence imaging. Amongst them, photochromic metal complexes offer the possibility of combining the specific properties of the metal centre and the optical response of the photochromic group. The synthesis, the electrochemical properties and the photophysical characterisation of a series of donor-acceptor azobenzene derivatives that possess bipyridine groups connected to a 4-dialkylaminoazobenzene moiety through various linkers are presented. DFT and TD-DFT calculations were performed to complement the experimental findings and contribute to their interpretation. The position and nature of the linker (ethynyl, triazolyl, none) were engineered and shown to induce different electronic coupling between donor and acceptor in ligands and complexes. This in turn led to strong modulations in terms of photoisomerisation of the ligands and complexes