12,337 research outputs found

    A DISAGGREGATED TIME-SERIES ANALYSIS OF EXPORT-BASE MODELS: A CASE STUDY ON ELKO COUNTY OF NEVADA

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    An important issue of debate in economic base literature is whether the export-base theory applies best to the short run, the long run, or both. An attempt is being made here in answering this crucial question by applying a two-step test for cointegration on quarterly employment data, and in gaining insights as to whether or not any unequivocal judgment can be made regarding the validity of the economic base hypothesis.International Relations/Trade,

    Optical Properties for Thin Film of Coumarin 334 Organic Laser Dye doped with PVA Polymer and Al2O3 Nanoparticles

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    Background: In this work, the optical properties for thin film of Coumarin 334 organic laser dye doped with PVA polymer and AL2O3 nanoparticles are determined at different concentrations, dissolved in ethanol solvent. Methods: Solutions at concentration (10-4 M) from coumarin (334) dye  in ethanol solvent at Different concentrations from dye (1, 3, 5, and 7)  ×10-5 M  were  prepared. Results: The AFM measurements show that the  grain size, root mean  square and roughness belong to the surface of the thin films rises with thickness rise for thin films  .  It has also increased the absorbance due to the increase in concentration. Conclusion: By using Gaussian beam from CW pulsed laser at 457 nm, we used Z-scan to study the nonlinear optical properties. The nonlinearity of thin film highly excels the pure dye solutions

    Damage in graphene due to electronic excitation induced by highly charged ions

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    Graphene is expected to be rather insensitive to ionizing particle radiation. We demonstrate that single layers of exfoliated graphene sustain significant damage from irradiation with slow highly charged ions. We have investigated the ion induced changes of graphene after irradiation with highly charged ions of different charge states (q = 28-42) and kinetic energies E_kin = 150-450 keV. Atomic force microscopy images reveal that the ion induced defects are not topographic in nature but are related to a significant change in friction. To create these defects, a minimum charge state is needed. In addition to this threshold behaviour, the required minimum charge state as well as the defect diameter show a strong dependency on the kinetic energy of the projectiles. From the linear dependency of the defect diameter on the projectile velocity we infer that electronic excitations triggered by the incoming ion in the above-surface phase play a dominant role for this unexpected defect creation in graphene

    Fast and robust spin manipulation in a quantum dot by electric fields

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    We apply an invariant-based inverse engineering method to control by time-dependent electric fields electron spin dynamics in a quantum dot with spin-orbit coupling in a weak magnetic field. The designed electric fields provide a shortcut to adiabatic processes that flips the spin rapidly, thus avoiding decoherence effects. This approach, being robust with respect to the device-dependent noise, can open new possibilities for the spin-based quantum information processing.Comment: 7 pages, 6 figures, with supplemental material. Errors in the published version have been correcte

    Single crystal growth, structure and magnetic properties of Pr2Hf2O7 pyrochlore

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    Large single crystals of the pyrochlore Pr2Hf2O7 have been successfully grown by the floating zone technique using an optical furnace equipped with high power Xenon arc lamps. Structural investigations have been carried out by both synchrotron X-ray and neutron powder diffraction to establish the crystallographic structure of the materials produced. The magnetic properties of the single crystals have been determined for magnetic fields applied along different crystallographic axes. The results reveal that Pr2Hf2O7 is an interesting material for further investigations as a frustrated magnet. The high quality of the crystals produced make them ideal for detailed investigations, especially those using neutron scattering techniques.Comment: Accepted for publication in J. Phys.: Condens. Matte

    Fibrosis in diabetes complications: Pathogenic mechanisms and circulating and urinary markers

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    Diabetes mellitus is characterized by a lack of insulin causing elevated blood glucose, often with associated insulin resistance. Over time, especially in genetically susceptible individuals, such chronic hyperglycemia can cause tissue injury. One pathological response to tissue injury is the development of fibrosis, which involves predominant extracellular matrix (ECM) accumulation. The main factors that regulate ECM in diabetes are thought to be pro-sclerotic cytokines and protease/anti-protease systems. This review will examine the key markers and regulators of tissue fibrosis in diabetes and whether their levels in biological fluids may have clinical utility

    Correlation Functions and Spin

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    The k-electron correlation function of a free chaotic electron beam is derived with the spin degree of freedom taken into account. It is shown that it can be expressed with the help of correlation functions for a polarized electron beam of all orders up to k and the degree of spin polarization. The form of the correlation function suggests that if the electron beam is not highly polarized, observing multi-particle correlations should be difficult. The result can be applied also to chaotic photon beams, the degree of spin polarization being replaced by the degree of polarization.Comment: 6 pages, 1 eps figure, accepted to Phys. Rev.

    Optimized Dynamical Decoupling for Time Dependent Hamiltonians

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    The validity of optimized dynamical decoupling (DD) is extended to analytically time dependent Hamiltonians. As long as an expansion in time is possible the time dependence of the initial Hamiltonian does not affect the efficiency of optimized dynamical decoupling (UDD, Uhrig DD). This extension provides the analytic basis for (i) applying UDD to effective Hamiltonians in time dependent reference frames, for instance in the interaction picture of fast modes and for (ii) its application in hierarchical DD schemes with π\pi pulses about two perpendicular axes in spin space. to suppress general decoherence, i.e., longitudinal relaxation and dephasing.Comment: 5 pages, no figure
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