11,996 research outputs found

    Scale invariant correlations and the distribution of prime numbers

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    Negative correlations in the distribution of prime numbers are found to display a scale invariance. This occurs in conjunction with a nonstationary behavior. We compare the prime number series to a type of fractional Brownian motion which incorporates both the scale invariance and the nonstationary behavior. Interesting discrepancies remain. The scale invariance also appears to imply the Riemann hypothesis and we study the use of the former as a test of the latter.Comment: 13 pages, 8 figures, version to appear in J. Phys.

    A comparison of cognitive restructuring and thought listing for excessive acquiring in hoarding disorder

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    Excessive acquiring is a common symptom of hoarding disorder (HD). Little is known about subjective distress associated with acquiring in HD. The present study examined acquiring- related distress and reactions to cognitive restructuring (CR) in 92 individuals with HD and 66 community control (CC) participants. All participants identified an item of interest at a high-risk acquiring location and then decided whether or not to acquire the item. HD participants completed the acquiring task while receiving a CR-based intervention or a thought-listing (TL) control condition. Results showed that HD participants reported more severe distress and greater urges to acquire the item of interest than did CC participants. Nevertheless, subjective distress decreased in both groups following the acquiring task. There were no differences in acquiring- related distress between the CR and TL conditions. The findings indicate that subjective distress may decrease after relatively short periods of time in individuals with HD, but that a single session of CR may not alleviate acquiring-related distress in HD participants.R01 MH068007 - NIMH NIH HHS; R01 MH068008 - NIMH NIH HHSAccepted manuscrip

    Learning cover context-free grammars from structural data

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    We consider the problem of learning an unknown context-free grammar when the only knowledge available and of interest to the learner is about its structural descriptions with depth at most â„“.\ell. The goal is to learn a cover context-free grammar (CCFG) with respect to â„“\ell, that is, a CFG whose structural descriptions with depth at most â„“\ell agree with those of the unknown CFG. We propose an algorithm, called LAâ„“LA^\ell, that efficiently learns a CCFG using two types of queries: structural equivalence and structural membership. We show that LAâ„“LA^\ell runs in time polynomial in the number of states of a minimal deterministic finite cover tree automaton (DCTA) with respect to â„“\ell. This number is often much smaller than the number of states of a minimum deterministic finite tree automaton for the structural descriptions of the unknown grammar

    A note on the calculation of the effective range

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    The closed form of the first order non-linear differential equation that is satisfied by the effective range within the variable phase formulation of scattering theory is discussed. It is shown that the conventional method of determining the effective range, by fitting a numerical solution of the Schr\"odinger equation to known asymptotic boundary conditions, can be modified to include the first order contribution of a long range interaction.Comment: 4 page

    Agents Play Mix-game

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    In mix-game which is an extension of minority game, there are two groups of agents; group1 plays the majority game, but the group2 plays the minority game. This paper studies the change of the average winnings of agents and volatilities vs. the change of mixture of agents in mix-game model. It finds that the correlations between the average winnings of agents and the mean of local volatilities are different with different combinations of agent memory length when the proportion of agents in group 1 increases. This study result suggests that memory length of agents in group1 be smaller than that of agent in group2 when mix-game model is used to simulate the financial markets.Comment: 8 pages, 6 figures, 3 table

    Bi-layer Kinetic Inductance Detectors for space observations between 80-120 GHz

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    We have developed Lumped Element Kinetic Inductance Detectors (LEKID) sensitive in the frequency band from 80 to 120~GHz. In this work, we take advantage of the so-called proximity effect to reduce the superconducting gap of Aluminium, otherwise strongly suppressing the LEKID response for frequencies smaller than 100~GHz. We have designed, produced and optically tested various fully multiplexed arrays based on multi-layers combinations of Aluminium (Al) and Titanium (Ti). Their sensitivities have been measured using a dedicated closed-circle 100 mK dilution cryostat and a sky simulator allowing to reproduce realistic observation conditions. The spectral response has been characterised with a Martin-Puplett interferometer up to THz frequencies, and with a resolution of 3~GHz. We demonstrate that Ti-Al LEKID can reach an optical sensitivity of about 1.41.4 10−1710^{-17}~W/Hz0.5W/Hz^{0.5} (best pixel), or 2.22.2 10−1710^{-17}~W/Hz0.5W/Hz^{0.5} when averaged over the whole array. The optical background was set to roughly 0.4~pW per pixel, typical for future space observatories in this particular band. The performance is close to a sensitivity of twice the CMB photon noise limit at 100~GHz which drove the design of the Planck HFI instrument. This figure remains the baseline for the next generation of millimetre-wave space satellites.Comment: 7 pages, 9 figures, submitted to A&

    A Comparison of Cognitive Restructuring And Thought Listing For Excessive Acquiring In Hoarding Disorder

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    Excessive acquiring is a common symptom of hoarding disorder (HD). Little is known about subjective distress associated with acquiring in HD. The present study examined acquiring-related distress and reactions to cognitive restructuring (CR) in 92 individuals with HD and 66 community control (CC) participants. All participants identified an item of interest at a high-risk acquiring location and then decided whether or not to acquire the item. HD participants completed the acquiring task while receiving a CR-based intervention or a thought-listing (TL) control condition. Results showed that HD participants reported more severe distress and greater urges to acquire the item of interest than did CC participants. Nevertheless, subjective distress decreased in both groups following the acquiring task. There were no differences in acquiring-related distress between the CR and TL conditions. The findings indicate that subjective distress may decrease after relatively short periods of time in individuals with HD, but that a single session of CR may not alleviate acquiring-related distress in HD participants

    Microscopic Theory of Josephson Mesoscopic Constrictions

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    We present a microscopic theory for the d.c. Josephson effect in model mesoscopic constrictions. Our method is based on a non-equilibrium Green function formalism which allows for a self-consistent determination of the order parameter profile along the constriction. The various regimes defined by the different length scales (Fermi wavelength λF\lambda_F, coherence length ξ0\xi_0 and constriction length LCL_C) can be analyzed, including the case where all these lengths are comparable. For the case λF<~(LC,ξ0)\lambda_F \tilde{<} (L_C,\xi_0) phase oscillations with spatial period λF/2\lambda_F/2 can be observed. In the case of LC>ξ0L_C>\xi_0 solutions with a phase-slip center inside the constriction can be found, in agreement with previous phenomenological theories.Comment: 4 pages (RevTex 3.0), 3 postscript figures available upon request, 312456-C

    Nonequilibrium orbital magnetization of strongly localized electrons

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    The magnetic response of strongly localized electrons to a time-dependent vector potential is considered. The orbital magnetic moment of the system, away from steady-state conditions, is obtained. The expression involves the tunneling and phonon-assisted hopping currents between localized states. The frequency and temperature dependence of the orbital magnetization is analyzed as function of the admittances connecting localized levels. It is shown that quantum interference of the localized wave functions contributes to the moment a term which follows adiabatically the time-dependent perturbation.Comment: RevTeX 3.

    Ab Initio Calculation of Crystalline Electric Fields and Kondo Temperatures in Ce-Compounds

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    We have calculated the band-ff hybridizations for Cex_xLa1−x_{1-x}M3_3 compounds (x=1x=1 and x→0x\rightarrow 0; M=Pb, In, Sn, Pd) within the local density approximation and fed this into a non-crossing approximation for the Anderson impurity model applied to both dilute and concentrated limits. Our calculations produce crystalline electric field splittings and Kondo temperatures with trends in good agreement with experiment and demonstrate the need for detailed electronic structure information on hybridization to describe the diverse behaviors of these Ce compounds.Comment: 13 pages(RevTeX), 3 Postscript figure
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