302 research outputs found

    Predicting Activation Across Individuals with Resting-State Functional Connectivity Based Multi-Atlas Label Fusion

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    The alignment of brain imaging data for functional neuroimaging studies is challenging due to the discrepancy between correspondence of morphology, and equivalence of functional role. In this paper we map functional activation areas across individuals by a multi-atlas label fusion algorithm in a functional space. We learn the manifold of resting-state fMRI signals in each individual, and perform manifold alignment in an embedding space. We then transfer activation predictions from a source population to a target subject via multi-atlas label fusion. The cost function is derived from the aligned manifolds, so that the resulting correspondences are derived based on the similarity of intrinsic connectivity architecture. Experiments show that the resulting label fusion predicts activation evoked by various experiment conditions with higher accuracy than relying on morphological alignment. Interestingly, the distribution of this gain is distributed heterogeneously across the cortex, and across tasks. This offers insights into the relationship between intrinsic connectivity, morphology and task activation. Practically, the mechanism can serve as prior, and provides an avenue to infer task-related activation in individuals for whom only resting data is available. Keywords: Functional Connectivity, Cortical Surface, Task Activation, Target Subject, Intrinsic ConnectivityCongressionally Directed Medical Research Programs (U.S.) (Grant PT100120)Eunice Kennedy Shriver National Institute of Child Health and Human Development (U.S.) (R01HD067312)Neuroimaging Analysis Center (U.S.) (P41EB015902)Oesterreichische Nationalbank (14812)Oesterreichische Nationalbank (15929)Seventh Framework Programme (European Commission) (FP7 2012-PIEF-GA-33003

    Measurement of the Ds Lifetime

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    We report the results of a precise measurement of the Ds meson lifetime based on 1662 +/- 56 fully reconstructed Ds -> phi pi decays, from the charm hadroproduction experiment E791 at Fermilab. Using an unbinned maximum likelihood fit, we measure the Ds lifetime to be 0.518 +/- 0.014 +/- 0.007 ps. The ratio of the measured Ds lifetime to the world average D0 lifetime is 1.25 +/- 0.04. This result differs from unity by six standard deviations, indicating significantly different lifetimes for the Ds and the D0.Comment: 12 pages, 3 figures, 2 table. LaTe

    Study of the Ds+ππ+π+D^+_s \to \pi^- \pi^+ \pi^+ decay and measurement of f0f_0 masses and widths

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    From a sample of 848 ±\pm 44 Ds+ππ+π+D_s^+ \to \pi^- \pi^+ \pi^+ decays, we find Γ(Ds+ππ+π+)/Γ(Ds+ϕπ+)=0.245±0.0280.012+0.019\Gamma(D_s^+ \to \pi^- \pi^+ \pi^+) / \Gamma(D_s^+ \to \phi \pi^+) = 0.245 \pm 0.028^{+0.019}_{-0.012} . Using a Dalitz plot analysis of this three body decay, we find significant contributions from the channels ρ0(770)π+\rho^0(770)\pi^+, ρ0(1450)π+\rho^0(1450)\pi^+, f0(980)π+f_0(980)\pi^+, f2(1270)π+f_2(1270)\pi^+, and f0(1370)π+f_0(1370)\pi^+. We present also the values obtained for masses and widths of the resonances f0(980)f_0(980) and f0(1370)f_0(1370).Comment: 10 pages, 3 eps figure

    Branching Fractions for D0 -> K+K- and D0 -> pi+pi-, and a Search for CP Violation in D0 Decays

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    Using the large hadroproduced charm sample collected in experiment E791 at Fermilab, we have measured ratios of branching fractions for the two-body singly-Cabibbo-suppressed charged decays of the D0: (D0 -> KK)/(D0 -> Kpi) = 0.109 +- 0.003 +- 0.003, (D0 -> pipi)/(D0 -> Kpi) = 0.040 +- 0.002 +- 0.003, and (D0 -> KK)/(D0 -> pipi) = 2.75 +- 0.15 +- 0.16. We have looked for differences in the decay rates of D0 and D0bar to the CP eigenstates K+K- and pi+pi-, and have measured the CP asymmetry parameters A_CP(K+K-) = -0.010 +- 0.049 +- 0.012 and A_CP(pi+pi-) = -0.049 +- 0.078 +- 0.030, both consistent with zero.Comment: 10 Postscript pages, including 2 figures. Submitted to Phys. Lett.

    Search for the Flavor-Changing Neutral-Current Decays D+π+μ+μD^+\to \pi^+ \mu^+ \mu^- and D+π+e+eD^+\to \pi^+ e^+ e^-

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    We report the results of a search for the flavor-changing neutral-current decays D+π+μ+μD^+\rightarrow \pi^+ \mu^+ \mu^- and D+π+e+eD^+\rightarrow \pi^+ e^+ e^- in data from Fermilab charm hadroproduction experiment E791. No signal above background is found, and we obtain upper limits on branching fractions, B(D+π+μ+μ)<1.8×105B(D^+\rightarrow \pi^+ \mu^+ \mu^-) < 1.8 \times 10^{-5} and B(D+π+e+e)<6.6×105B(D^+\rightarrow \pi^+ e^+ e^-) < 6.6 \times 10^{-5}, at the 90\% confidence level.Comment: nine pages with figures; compressed, uuencoded postscrip

    Search for Rare and Forbidden Dilepton Decays of the D+, Ds, and D0 Charmed Mesons

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    We report the results of a search for flavor-changing neutral current, lepton-flavor violating, and lepton-number violating decays of D+, Ds, and D0 mesons (and their antiparticles) into modes containing muons and electrons. Using data from Fermilab charm hadroproduction experiment E791, we examine the pi,l,l and K,l,l decay modes of D+ and Ds and the l+l- decay modes of D0. No evidence for any of these decays is found. Therefore, we present branching-fraction upper limits at 90% confidence level for the 24 decay modes examined. Eight of these modes have no previously reported limits, and fourteen are reported with significant improvements over previously published results.Comment: 12 pages, 3 figures, LaTeX, elsart.cls, epsf.sty, amsmath.sty Submitted to Physics Letters

    Search for CP Violation in Charged D Meson Decays

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    We report results of a search for CP violation in the singly Cabibbo-suppressed decays D+ -> K- K+ pi+, phi pi+, K*(892)0 K+, and pi- pi+ pi+ based on data from the charm hadroproduction experiment E791 at Fermilab. We search for a difference in the D+ and D- decay rates for each of the final states. No evidence for a difference is seen. The decay rate asymmetry parameters A(CP), defined as the difference in the D+ and D- decay rates divided by the sum of the decay rates, are measured to be: A(CP)(K K pi) = -0.014 +/- 0.029, A(CP)(phi pi) = -0.028 +/- 0.036, A(CP)(K*(892) K) = -0.010 +/- 0.050, and A(CP)(pi pi pi) = -0.017 +/- 0.042.Comment: 13 pages, 5 figures, 1 table; Elsevier LaTe

    Measurement of the form-factor ratios for D+ --> K* l nu

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    The form factor ratios rv=V(0)/A1(0), r2=A2(0)/A1(0) and r3=A3(0)/A1(0) in the decay D+ --> K* l nu, K* -->K-pi+ have been measured using data from charm hadroproduction experiment E791 at Fermilab. From 3034 (595) signal (background) events in the muon channel, we obtain rv=1.84+-0.11+-0.09, r2=0.75+-0.08+-0.09 and, as a first measurement of r3, we find 0.04+-0.33 +-0.29. The values of the form factor ratios rv and r2 measured for the muon channel are combined with the values of rv and r2 that we have measured in the electron channel. The combined E791 results for the muon and electron channels are rv=1.87+-0.08+-0.07 and r2=0.73+-0.06+-0.08.Comment: 9 pages + 3 figures ; submitted to PL
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