412 research outputs found

    Modified Paouris inequality

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    The Paouris inequality gives the large deviation estimate for Euclidean norms of log-concave vectors. We present a modified version of it and show how the new inequality may be applied to derive tail estimates of l_r-norms and suprema of norms of coordinate projections of isotropic log-concave vectors.Comment: 14 page

    Modelling water infiltration into macroporous hill slopes using special boundary conditions

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    The formulation of suitable boundary conditions is a very crucial task when modeling water infiltration into macroporous hill slopes. The processes of water infiltration and exfiltration vary in space and time and depend on the flow on the surface as well as in the subsurface. In this contribution we have purposed special system process dependent boundary conditions can be formulated for a two-phase dual-permeability model to simulate infiltration and exfiltration processes. The presented formulation analyses the saturation conditions of the dual-permeability model (e.g. saturation) at the boundary nodes and adopts the boundary conditions depending on the processes at the soil surface such as rainfall intensity. Using a simplified macroporous hill slope and a heavy rainfall event we demonstrate the functionality of our formulation

    An efficiency upper bound for inverse covariance estimation

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    We derive an upper bound for the efficiency of estimating entries in the inverse covariance matrix of a high dimensional distribution. We show that in order to approximate an off-diagonal entry of the density matrix of a dd-dimensional Gaussian random vector, one needs at least a number of samples proportional to dd. Furthermore, we show that with nâ‰Șdn \ll d samples, the hypothesis that two given coordinates are fully correlated, when all other coordinates are conditioned to be zero, cannot be told apart from the hypothesis that the two are uncorrelated.Comment: 7 Page

    The LIL for UU-statistics in Hilbert spaces

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    We give necessary and sufficient conditions for the (bounded) law of the iterated logarithm for UU-statistics in Hilbert spaces. As a tool we also develop moment and tail estimates for canonical Hilbert-space valued UU-statistics of arbitrary order, which are of independent interest

    Muon Catalyzed Fusion in 3 K Solid Deuterium

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    Muon catalyzed fusion in deuterium has traditionally been studied in gaseous and liquid targets. The TRIUMF solid-hydrogen-layer target system has been used to study the fusion reaction rates in the solid phase of D_2 at a target temperature of 3 K. Products of two distinct branches of the reaction were observed; neutrons by a liquid organic scintillator, and protons by a silicon detector located inside the target system. The effective molecular formation rate from the upper hyperfine state of Όd\mu d and the hyperfine transition rate have been measured: λ~(3/2)=2.71(7)stat.(32)syst.Ό/s\tilde{\lambda}_(3/2)=2.71(7)_{stat.}(32)_{syst.} \mu/s, and λ~(3/2)(1/2)=34.2(8)stat.(1)syst.Ό/s\tilde{\lambda}_{(3/2)(1/2)} =34.2(8)_{stat.}(1)_{syst.} \mu /s. The molecular formation rate is consistent with other recent measurements, but not with the theory for isolated molecules. The discrepancy may be due to incomplete thermalization, an effect which was investigated by Monte Carlo calculations. Information on branching ratio parameters for the s and p wave d+d nuclear interaction has been extracted.Comment: 19 pages, 11 figures, submitted to PRA Feb 20, 199

    Measurement of the Resonant dÎŒtd\mu t Molecular Formation Rate in Solid HD

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    Measurements of muon-catalyzed dt fusion (dÎŒt→4He+n+Ό−d\mu t \to ^4He+n+\mu^-) in solid HD have been performed. The theory describing the energy dependent resonant molecular formation rate for the reaction ÎŒt\mu t + HD →[(dÎŒt)pee]∗\to [(d\mu t)pee]^* is compared to experimental results in a pure solid HD target. Constraints on the rates are inferred through the use of a Monte Carlo model developed specifically for the experiment. From the time-of- flight analysis of fusion events in 16 and 37 ÎŒg⋅cm−2\mu g\cdot cm^{-2} targets, an average formation rate consistent with 0.897±\pm(0.046)stat±_{stat}\pm (0.166)syst_{syst} times the theoretical prediction was obtained.Comment: 4 pages, 5 figure
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