5,558 research outputs found

    Regional Indexes of Activity: Combining the Old with the New

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    This paper proposes a framework to construct indexes of activity which links two strands of the index literature – the traditional business cycle analysis and the latent variable approach. To illustrate the method, we apply the framework to Australian regional data, namely to two resource-rich and two service-based states. The results reveal differences in the evolution and drivers of economic activity across the four states. We also demonstrate the value of the Index in a broader context by using a structural vector autoregression (SVAR) approach to analyse the effects of shocks from the US and from China. This Index-SVAR approach facilitates a richer analysis because the unique feature of the index method proposed here allows impulse responses to be traced back to the components.Regional economic activity, coincident indicators, dynamic latent factor model

    Strong duality in conic linear programming: facial reduction and extended duals

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    The facial reduction algorithm of Borwein and Wolkowicz and the extended dual of Ramana provide a strong dual for the conic linear program (P)sup<c,x>AxKb (P) \sup {<c, x> | Ax \leq_K b} in the absence of any constraint qualification. The facial reduction algorithm solves a sequence of auxiliary optimization problems to obtain such a dual. Ramana's dual is applicable when (P) is a semidefinite program (SDP) and is an explicit SDP itself. Ramana, Tuncel, and Wolkowicz showed that these approaches are closely related; in particular, they proved the correctness of Ramana's dual using certificates from a facial reduction algorithm. Here we give a clear and self-contained exposition of facial reduction, of extended duals, and generalize Ramana's dual: -- we state a simple facial reduction algorithm and prove its correctness; and -- building on this algorithm we construct a family of extended duals when KK is a {\em nice} cone. This class of cones includes the semidefinite cone and other important cones.Comment: A previous version of this paper appeared as "A simple derivation of a facial reduction algorithm and extended dual systems", technical report, Columbia University, 2000, available from http://www.unc.edu/~pataki/papers/fr.pdf Jonfest, a conference in honor of Jonathan Borwein's 60th birthday, 201

    Phenomenological Consequences of Right-handed Down Squark Mixings

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    The mixings of dRd_R quarks, hidden from view in Standard Model (SM), are naturally the largest if one has an Abelian flavor symmetry. With supersymmetry (SUSY) their effects can surface via d~R\tilde d_R squark loops. Squark and gluino masses are at TeV scale, but they can still induce effects comparable to SM in BdB_d (or BsB_s) mixings, while D0D^0 mixing could be close to recent hints from data. In general, CP phases would be different from SM, as may be indicated by recent B Factory data. Presence of non-standard soft SUSY breakings with large tanβ\tan\beta could enhance bdγb\to d\gamma (or sγs\gamma) transitions.Comment: Version to appear in Phys. Rev. Let

    Quantum Hall Effect and Quantum Point Contact in Bilayer-Patched Epitaxial Graphene

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    We study an epitaxial graphene monolayer with bilayer inclusions via magnetotransport measurements and scanning gate microscopy at low temperatures. We find that bilayer inclusions can be metallic or insulating depending on the initial and gated carrier density. The metallic bilayers act as equipotential shorts for edge currents, while closely spaced insulating bilayers guide the flow of electrons in the monolayer constriction, which was locally gated using a scanning gate probe.Comment: 5 pages, 5 figure

    SU(3) and Nonet Breaking Effects in KLγγK_L \to \gamma \gamma Induced by sd+2gluons \to d + 2{gluon} due to Anomaly

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    In this paper we study the effects of sd+2gluons\to d + 2{gluon} on KLγγK_L \to \gamma\gamma in the Standard Model. We find that this interaction can induce new sizeable SU(3) and U(3) nonet breaking effects in KLη,ηK_L - \eta, \eta' transitions and therefore in KLγγK_L\to \gamma\gamma due to large matrix elements of from QCD anomaly. These new effects play an important role in explaining the observed value. We also study the effects of this interaction on the contribution to ΔmKLKS\Delta m_{K_L-K_S}.Comment: RevTex, 12 Pages, no figures. Version to be published in PR

    Low-Mass Baryon-Antibaryon Enhancements in B Decays

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    The nature of low-mass baryon-antibaryon enhancements seen in B decays is explored. Three possibilities include (i) states near threshold as found in a model by Nambu and Jona-Lasinio, (ii) isoscalar states with JPC=0±+J^{PC} = 0^{\pm +} coupled to a pair of gluons, and (iii) low-mass enhancements favored by the fragmentation process. Ways of distinguishing these mechanisms using angular distributions and flavor symmetry are proposed.Comment: 8 pages, LaTeX, no figures, to be submitted to Phys. Rev. D. One reference adde

    Microwave assisted heterogeneous catalysis: effects of varying oxygen concentrations on the oxidative coupling of methane

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    The oxidative coupling of methane was investigated over alumina supported La2O3/CeO2 catalysts under microwave dielectric heating conditions at different oxygen concentrations. It was observed that, at a given temperature using microwave heating, selectivities for both ethane and ethylene were notably higher when oxygen was absent than that in oxygen/methane mixtures. The differences were attributed to the localised heating of microwave radiation resulting in temperature inhomogeneity in the catalyst bed. A simplified model was used to estimate the temperature inhomogeneity; the temperature at the centre of the catalyst bed was 85 °C greater than that at the periphery when the catalyst was heated by microwaves in a gas mixture with an oxygen concentration of 12.5% (v/v), and the temperature difference was estimated to be 168 °C in the absence of oxygen

    MRI brain scan study of minor physical anomalies to aid the early diagnosis of autism

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    Poster Sessionspublished_or_final_versionThe 27th International College of Neuropsychopharmacology Congress (CINP 2010), Hong Kong, China, 6-10 June 2010. In International Journal of Neuropsychopharmacology, 2010, v. 13, suppl. S1, p. 182, abstract no. P-14.03

    The Fourth Element: Characteristics, Modelling, and Electromagnetic Theory of the Memristor

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    In 2008, researchers at HP Labs published a paper in {\it Nature} reporting the realisation of a new basic circuit element that completes the missing link between charge and flux-linkage, which was postulated by Leon Chua in 1971. The HP memristor is based on a nanometer scale TiO2_2 thin-film, containing a doped region and an undoped region. Further to proposed applications of memristors in artificial biological systems and nonvolatile RAM (NVRAM), they also enable reconfigurable nanoelectronics. Moreover, memristors provide new paradigms in application specific integrated circuits (ASICs) and field programmable gate arrays (FPGAs). A significant reduction in area with an unprecedented memory capacity and device density are the potential advantages of memristors for Integrated Circuits (ICs). This work reviews the memristor and provides mathematical and SPICE models for memristors. Insight into the memristor device is given via recalling the quasi-static expansion of Maxwell's equations. We also review Chua's arguments based on electromagnetic theory.Comment: 28 pages, 14 figures, Accepted as a regular paper - the Proceedings of Royal Society
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