47,677 research outputs found

    Forecast Rationality and Monetary Policy Frameworks: Evidence from UK Interest Rate Forecasts

    Get PDF
    This paper explores the heterogeneity and rationality of professional forecasts at both short and long forecast horizons. We employ disaggregated survey data for forecasts of three-month inter-bank rates and ten-year gilt yields for the period 1989-2006. We find evidence of heterogeneity among forecasters. Moreover, forecasts violate both the unbiasedness and orthogonality conditions of the rational expectations hypothesis. The majority of biased forecasts underestimate the future spot rate. The rationality of forecasts varies across maturities and forecast horizons with short horizon and short maturity forecasts exhibiting more rationality. It also varies across sub-periods corresponding to different monetary policy frameworks. We produce evidence indicating that both monetary policy actions and elements of communication policy have information content regarding the rationality of forecasts. Changes in official bank rates and disagreement, as recorded in the minutes of the Monetary Policy Committee, influence the rationality of forecasts. The publication of inflation reports has no effect

    Recursions for distribution functions and stop-loss transforms.

    Get PDF
    For any functions on the non-negative integers, we can evaluate the cumulative function given by (s) = sx=o(x) from the values of by the recursion (s) = (s - 1) + (s). Analogously we can use this procedure t times to evaluate the t-th order cumulative function t when itself satisfies a certain sort of recursion. We shall also derive recursions for the tth order tails t where (s) = x=s+1(x). The recursions can be applied for exact and approximate evaluation of distribution functions and stop-loss transforms of probability distributions. The class of recursions for includes the classes discussed by Sundt (1992), incorporating the class studied by Panjer (1981). We discuss in particular convolutions and compound functions.Distribution; Functions;

    Minimum Wage and Compliance in a Model of Search On-the-Job

    Get PDF
    minimum wages, compliance, job search, wage growth

    Critical slowing down and hyperuniformity on approach to jamming

    Full text link
    Hyperuniformity characterizes a state of matter that is poised at a critical point at which density or volume-fraction fluctuations are anomalously suppressed at infinite wavelengths. Recently, much attention has been given to the link between strict jamming and hyperuniformity in frictionless hard-particle packings. Doing so requires one to study very large packings, which can be difficult to jam properly. We modify the rigorous linear programming method of Donev et al. [J. Comp. Phys. 197, 139 (2004)] in order to test for jamming in putatively jammed packings of hard-disks in two dimensions. We find that various standard packing protocols struggle to reliably create packings that are jammed for even modest system sizes; importantly, these packings appear to be jammed by conventional tests. We present evidence that suggests that deviations from hyperuniformity in putative maximally random jammed (MRJ) packings can in part be explained by a shortcoming in generating exactly-jammed configurations due to a type of "critical slowing down" as the necessary rearrangements become difficult to realize by numerical protocols. Additionally, various protocols are able to produce packings exhibiting hyperuniformity to different extents, but this is because certain protocols are better able to approach exactly-jammed configurations. Nonetheless, while one should not generally expect exact hyperuniformity for disordered packings with rattlers, we find that when jamming is ensured, our packings are very nearly hyperuniform, and deviations from hyperuniformity correlate with an inability to ensure jamming, suggesting that strict jamming and hyperuniformity are indeed linked. This raises the possibility that the ideal MRJ packings have no rattlers. Our work provides the impetus for the development of packing algorithms that produce large disordered strictly jammed packings that are rattler-free.Comment: 15 pages, 11 figures. Accepted for publication in Phys. Rev.

    [Colored solutions of Yang-Baxter equation from representations of U_{q}gl(2)]

    Full text link
    We study the Hopf algebra structure and the highest weight representation of a multiparameter version of Uqgl(2)U_{q}gl(2). The commutation relations as well as other Hopf algebra maps are explicitly given. We show that the multiparameter universal R{\cal R} matrix can be constructed directly as a quantum double intertwiner, without using Reshetikhin's transformation. An interesting feature automatically appears in the representation theory: it can be divided into two types, one for generic qq, the other for qq being a root of unity. When applying the representation theory to the multiparameter universal R{\cal R} matrix, the so called standard and nonstandard colored solutions R(μ,ν;μ′,ν′)R(\mu,\nu; {\mu}', {\nu}') of the Yang-Baxter equation is obtained.Comment: [14]pages, latex, no figure

    Do methanethiol adsorbates on the Au(111) surface dissociate?

    Full text link
    The interaction of methanethiol molecules CH3_{3}SH with the Au(111) surface is investigated, and it is found for the first time that the S-H bond remains intact when the methanethiol molecules are adsorbed on the regular Au(111) surface. However, it breaks if defects are present in the Au(111) surface. At low coverage, the fcc region is favored for S atom adsorption, but at saturated coverage the adsorption energies at various sites are almost iso-energetic. The presented calculations show that a methanethiol layer on the regular Au(111) surface does not dimerize.Comment: 4 pages, 2 figures, 4 tables, submitted to Phys. Rev. Let

    Evolving Network With Different Edges

    Full text link
    We proposed an evolving network model constituted by the same nodes but different edges. The competition between nodes and different links were introduced. Scale free properties have been found in this model by continuum theory. Different network topologies can be generated by some tunable parameters. Simulation results consolidate the prediction.Comment: 14 pages, 9 figures, some contents revised, fluctuation of x degree adde

    Neutrino mixing with broken S3S_3 symmetry

    Full text link
    We explore the consequences of assuming that the neutrino mass matrix is a linear combination of the matrices of a three dimensional representation of the group S3S_3 and that it has one zero mass eigenvalue. When implemented, these two assumptions allow us to express the transformation matrix relating the mass eigenstates to the flavor eigenstates in terms of a single parameter which we fit to the available data.Comment: Final version. Published in Phys. Rev. D 82, 033005 (2010

    Unveiling Su Aurigae in the near Infrared: New high spatial resolution results using Adaptive Optics

    Full text link
    We present here new results on circumstellar nebulosity around SU Aurigae, a T-Tauri star of about 2 solar mass and 5 Myrs old at 152 pc in the J, H and K bands using high resolution adaptive optics imaging (0\farcs30) with the Penn state IR Imaging Spectrograph (PIRIS) at the 100 inch Mt. Wilson telescope. A comparison with HST STIS optical (0.2 to 1.1 micron) images shows that the orientation of the circumstellar nebulosity in the near-IR extends from PAs 210 to 270 degrees in H and K bands and up to 300 degrees in the J band. We call the circumstellar nebulosity seen between 210 to 270 degrees as 'IR nebulosity'. We find that the IR nebulosity (which extends up to 3.5 arcsecs in J band and 2.5 arcsecs in the K band) is due to scattered light from the central star. The IR nebulosity is either a cavity formed by the stellar outflows or part of the circumstellar disk. We present a schematic 3-dimensional geometrical model of the disk and jet of SU Aur based on STIS and our near-IR observations. According to this model the IR nebulosity is a part of the circumstellar disk seen at high inclination angles. The extension of the IR nebulosity is consistent with estimates of the disk diameter of 50 to 400 AU in radius, from earlier mm, K band interferometric observations and SED fittings.Comment: Accepted for publications in the Astronomical Journal, to appear in the May issue of the Journa
    • …
    corecore