231,369 research outputs found

    Macroeconomic Stability, Governance and Growth: Empirical Lessons from the Post-Communist Transition

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    Using panel data for the period 1989-2006 we revisit the empirics of economic growth in the context of the post-communist transition. We pay particular attention to the mechanisms of causation and to the potential endogeneity of the macroeconomic stability indicators considered to be important in the existing literature. Carefully employing a variety of econometric techniques we consistently find that macroeconomic instability is bad for economic growth. We find some evidence that institutions of governance are important for economic growth through their influence on the macroeconomic environment. That is, good institutions are conducive to macroeconomic stability which in turn positively impacts upon economic growth. We also find, in contrast with other work, that investments in education have had a strong positive impact on growth in transition while other 'standard' economic growth determinants remain less important. These findings are shown to be robust to a variety of econometric approaches, specifications and time spans

    Power-law Behavior of High Energy String Scatterings in Compact Spaces

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    We calculate high energy massive scattering amplitudes of closed bosonic string compactified on the torus. We obtain infinite linear relations among high energy scattering amplitudes. For some kinematic regimes, we discover that some linear relations break down and, simultaneously, the amplitudes enhance to power-law behavior due to the space-time T-duality symmetry in the compact direction. This result is consistent with the coexistence of the linear relations and the softer exponential fall-off behavior of high energy string scattering amplitudes as we pointed out prevously. It is also reminiscent of hard (power-law) string scatterings in warped spacetime proposed by Polchinski and Strassler.Comment: 6 pages, no figure. Talk presented by Jen-Chi Lee at Europhysics Conference (EPS2007), Manchester, England, July 19-25, 2007. To be published by Journal of Physics: Conference Series

    Unified description of pairing, trionic and quarteting states for one-dimensional SU(4) attractive fermions

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    Paired states, trions and quarteting states in one-dimensional SU(4) attractive fermions are investigated via exact Bethe ansatz calculations. In particular, quantum phase transitions are identified and calculated from the quarteting phase into normal Fermi liquid, trionic states and spin-2 paired states which belong to the universality class of linear field-dependent magnetization in the vicinity of critical points. Moreover, unified exact results for the ground state energy, chemical potentials and complete phase diagrams for isospin S=1/2,1,3/2S=1/2, 1, 3/2 attractive fermions with external fields are presented. Also identified are the magnetization plateaux of mz=Ms/3m^z=M_s/3 and mz=2Ms/3m^z=2M_s/3, where MsM_s is the magnetization saturation value. The universality of finite-size corrections and collective dispersion relations provides a further test ground for low energy effective field theory.Comment: 13 pages, 4 figure

    Complete gradient-LC-ESI system on a chip for protein analysis

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    This paper presents the first fully integrated gradient-elution liquid chromatography-electrospray ionization (LC-ESI) system on a chip. This chip integrates a pair of high-pressure gradient pumps, a sample injection pump, a passive mixer, a packed separation column, and an ESI nozzle. We also present the successful on-chip separation of protein digests by reverse phase (RP)-LC coupled with on-line mass spectrometer (MS) analysis

    Ultra-Short Optical Pulse Generation with Single-Layer Graphene

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    Pulses as short as 260 fs have been generated in a diode-pumped low-gain Er:Yb:glass laser by exploiting the nonlinear optical response of single-layer graphene. The application of this novel material to solid-state bulk lasers opens up a way to compact and robust lasers with ultrahigh repetition rates.Comment: 6 pages, 3 figures, to appear in Journal of Nonlinear Optical Physics & Material

    The Possible Interstellar Anion CH2CN-: Spectroscopic Constants, Vibrational Frequencies, and Other Considerations

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    It is hypothesized that the A ^1B_1 <- X ^1A' excitation into the dipole-bound state of the cyanomethyl anion (CH2CN-) is proposed as the carrier for one diffuse interstellar band. However, this particular molecular system has not been detected in the interstellar medium even though the related cyanomethyl radical and the isoelectronic ketenimine molecule have been found. In this study we are employing the use of proven quartic force fields and second-order vibrational perturbation theory to compute accurate spectroscopic constants and fundamental vibrational frequencies for ^1A' CH2CN- in order to assist in laboratory studies and astronomical observations

    Metallic characteristics in superlattices composed of insulators, NdMnO3/SrMnO3/LaMnO3

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    We report on the electronic properties of superlattices composed of three different antiferromagnetic insulators, NdMnO3/SrMnO3/LaMnO3 grown on SrTiO3 substrates. Photoemission spectra obtained by tuning the x-ray energy at the Mn 2p -> 3d edge show a Fermi cut-off, indicating metallic behavior mainly originating from Mn e_g electrons. Furthermore, the density of states near the Fermi energy and the magnetization obey a similar temperature dependence, suggesting a correlation between the spin and charge degrees of freedom at the interfaces of these oxides

    Optical Spatial integration methods for ambiguity function generation

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    A coherent optical spatial integration approach to ambiguity function generation is described. It uses one dimensional acousto-optic Bragg cells as input tranducers in conjunction with a space variant linear phase shifter, a passive optical element, to generate the two dimensional ambiguity function in one exposure. Results of a real time implementation of this system are shown
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