Exploratory fMRI analysis without spatial normalization

Author Manuscript received 2010 March 11. 21st International Conference, IPMI 2009, Williamsburg, VA, USA, July 5-10, 2009. ProceedingsWe present an exploratory method for simultaneous parcellation of multisubject fMRI data into functionally coherent areas. The method is based on a solely functional representation of the fMRI data and a hierarchical probabilistic model that accounts for both inter-subject and intra-subject forms of variability in fMRI response. We employ a Variational Bayes approximation to fit the model to the data. The resulting algorithm finds a functional parcellation of the individual brains along with a set of population-level clusters, establishing correspondence between these two levels. The model eliminates the need for spatial normalization while still enabling us to fuse data from several subjects. We demonstrate the application of our method on a visual fMRI study.McGovern Institute for Brain Research at MIT. Neurotechnology ProgramNational Science Foundation (U.S.) (CAREER Grant 0642971)National Institutes of Health (U.S.) (NIBIB NAMIC U54-EB005149)National Institutes of Health (U.S.) (NCRR NAC P41-RR13218

Spin des niveaux à 0,46 et 0,67 MeV du 34Cl

L'étude de la réaction 32S(3He, pγ) 3Cl a été réalisée à l'aide d'un faisceau 3He++ aux énergies 9, 9,5 et 10 MeV. Les coïncidences pγ ont été effectuées entre protons détectés à 0° et rayonnements γ, conformément à la méthode II de corrélation angulaire de Litherland et Ferguson. L'exploitation des corrélations des groupes de protons menant aux deuxième et troisième niveaux excités du 34CI avec les rayonnements γ correspondants, détermine sans ambiguïté J = 1 pour les niveaux à 0,46 et 0,67 MeV de ce noyau. Ces résultats confirment les prévisions théoriques déduites du modèle en couches avec interaction à deux particules modifiée

Étude d'états excités de 22Ne a l'aide des résonances de capture radiative de particules alpha par 18O entre 1,6 et 5,0 MeV d'énergie incidente

La courbe d'excitation du rayonnement γ de 350 keV issu de la réaction 18O(α, nγ) 21Ne a été mesurée entre 1,6 et 5 MeV. Six nouvelles résonances ont été observées correspondant aux niveaux du 22Ne : Ex = 11,199 MeV (Eα = 1,873 MeV ; Γt = 7 keV) ; 11,271 (1,961 ; 7) ; 11,431 (2,156 ; 47) ; 11,519 (2,263 ; 6) ; 11,577 (2,335 ; 16) ; 11,745 (2,540 ; 41). Nous avons relevé les spectres de désexcitation par rayonnement γ de tous les niveaux mis en évidence et mesuré les distributions angulaires des rayonnements γ de la réaction 18O(α, γ) 22Ne chaque fois que l'intensité de transition le permettait. En fait seules trois résonances déjà observées se trouvaient dans ce cas. Pour le niveau Ex = 11,462 MeV (2,194 ; 9) la distribution angulaire a permis de fixer Jπ = 1 -. Pour les niveaux Ex = 11,682 MeV (2,463 ; 8) et Ex = 11,751 MeV (2,547 ; 8) les valeurs respectives J π = 2+ et Jπ = 1- ont été confirmées. Des rapports d'embranchement (γ0/γ1) ont pu être déterminés pour ces trois niveaux ainsi que les coefficients de mélange de multipolarité des transitions γ1. Des limites supérieures des intensités de transition ωγ pour les transitions γ0 + γ 1 sont données pour les autres niveaux

Agrotechnologies towards Ecotechnologies the three pillars for developing Eco-design

International audienceTo boost agrotechnologies towards ecotechnologies ("environmental technologies" according to ETAP programme of EU, or "more ecologically productive technologies" in the context of agriculture), we need to strengthen a "triple bottom" system: -To take into account, in "Life Cycle Analysis" methodologies, the natural variability in time and space of these applications in land use. - To develop an overall approach for realistic machinery qualification, in order to feed the environmental burdens accurately through relevant data bases collected on agrotechnologies in real action. - To work on Eco-innovation processes, by deepening specific innovation tools and methods, for implementation of innovative solutions chosen according to LCA results. This paper presents the concept, develops the methods and illustrates them by examples of results on organic spreading technologies

Micro-SQUID technique for studying the temperature dependence of switching fields of single nanoparticles

An improved micro-SQUID technique is presented allowing us to measure the temperature dependence of the magnetisation switching fields of single nanoparticles well above the critical superconducting temperature of the SQUID. Our first measurements on 3 nm cobalt nanoparticle embedded in a niobium matrix are compared to the Neel Brown model describing the magnetisation reversal by thermal activation over a single anisotropy barrier.Comment: 3 pages, 4 figures; conference proceeding: 1st Joint European Magnetic Symposia (JEMS'01), Grenoble (France), 28th August - 1st September, 200

Selection of mouse cells with amplified metallothionein genes retaining their glucocorticoid inducibility

AbstractTwo new mouse cell mutants, resistant to either 80 or 100 mM CdCl2, were isolated to study the regulation of transcription by the glucocorticoid hormones. Their metallothionein mt-1+ and mt-2+ genes were amplified coordinately to a maximum of 30 copies per cell. By Southern blot analysis, no gross rearrangement was detectable near the mt+ loci. Contrary to other mutants previously isolated, the metallothionein-specific mRNAs of these mutants are inducible by dexamethasone

Notes

Notes by Charles M. Urruela, Norman B. Thirion, R. F. Swisher, Peter Francis Nemeth, Walter C. Ivansevic, Charles M. Boynton, Theodore P. Frericks, Hal Hunter, and J. D. Kelly

Josephson junctions and superconducting quantum interference devices made by local oxidation of niobium ultrathin films

We present a method for fabricating Josephson junctions and superconducting quantum interference devices (SQUIDs) which is based on the local anodization of niobium strip lines 3 to 6.5 nm-thick under the voltage-biased tip of an Atomic Force Microscope. Microbridge junctions and SQUID loops are obtained either by partial or total oxidation of the niobium layer. Two types of weak link geometries are fabricated : lateral constriction (Dayem bridges) and variable thickness bridges. SQUIDs based on both geometries show a modulation of the maximum Josephson current with a magnetic flux periodic with respect to the superconducting flux quantum h/2e. They persist up to 4K. The modulation shape and depth for SQUIDs based on variable thickness bridges indicate that the weak link size becomes comparable to the superconducting film coherence length which is of the order of 10nm.Comment: 12 page

Fast Optimal Transport Averaging of Neuroimaging Data

Knowing how the Human brain is anatomically and functionally organized at the level of a group of healthy individuals or patients is the primary goal of neuroimaging research. Yet computing an average of brain imaging data defined over a voxel grid or a triangulation remains a challenge. Data are large, the geometry of the brain is complex and the between subjects variability leads to spatially or temporally non-overlapping effects of interest. To address the problem of variability, data are commonly smoothed before group linear averaging. In this work we build on ideas originally introduced by Kantorovich to propose a new algorithm that can average efficiently non-normalized data defined over arbitrary discrete domains using transportation metrics. We show how Kantorovich means can be linked to Wasserstein barycenters in order to take advantage of an entropic smoothing approach. It leads to a smooth convex optimization problem and an algorithm with strong convergence guarantees. We illustrate the versatility of this tool and its empirical behavior on functional neuroimaging data, functional MRI and magnetoencephalography (MEG) source estimates, defined on voxel grids and triangulations of the folded cortical surface.Comment: Information Processing in Medical Imaging (IPMI), Jun 2015, Isle of Skye, United Kingdom. Springer, 201