115,046 research outputs found

    On the Reliability of the Langevin Pertubative Solution in Stochastic Inflation

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    A method to estimate the reliability of a perturbative expansion of the stochastic inflationary Langevin equation is presented and discussed. The method is applied to various inflationary scenarios, as large field, small field and running mass models. It is demonstrated that the perturbative approach is more reliable than could be naively suspected and, in general, only breaks down at the very end of inflation.Comment: 7 pages, 3 figure

    Conditioning of pulses from aerosol-particle detectors

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    Pulse-conditioner translates pulses generated by aerosol-particle detectors to a form acceptable by commercially available pulse height analyzers designed for nuclear-energy spectroscopy

    Ejaculate allocation by male sand martins, Riparia riparia

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    Males of many species allocate sperm to ejaculates strategically in response to variation in the risk and intensity of sperm competition. The notable exception is passerine birds, in which evidence for strategic allocation is absent. Here we report the results of a study testing for strategic ejaculate allocation in a passerine bird, the sand martin (Riparia riparia). Natural ejaculates were collected from males copulating with a model female. Ejaculates transferred in the presence of a rival male contained significantly more sperm than ejaculates transferred in the absence of a rival male. There was no evidence that this difference was due to the confounding effects of the year of ejaculate collection, the identity of the model female, the colony, the stage of season or the period of the day in which ejaculates were collected. A more detailed examination of the ejaculate patterns of individual males, achieved by the DNA profiling of ejaculates, provided additional evidence for strategic allocation of sperm

    Rediscounting Under Aggregate Risk with Moral Hazard

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    Freeman (1999) proposes a model in which discount window lending and open market operations have different effects. This is important because in most of the literature, these policies are indistinguishable. However, Freeman's argument that the central bank should absorb losses associated with default to provide risk-sharing stands in stark contrast to the concern that central banks should limit their exposure to credit risk. We extend Freeman's model by introducing moral hazard. With moral hazard, the central bank should avoid absorbing losses and Freeman's argument breaks down. However, we show that policies resembling discount window lending and open market operations can still be distinguished in this new framework. The optimal policy is for the central bank to make a restricted number of creditors compete for funds. By restricting the number of agents, the central bank can limit the moral hazard problem. By making them compete with each other, the central bank can exploit market information that reveals the state of the economy.Payment, clearing, and settlement systems; Financial markets; Central bank research

    GEODYN operations description, volume 3

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    The operating and set-up procedures for the multi-satellite, multi-arc GEODYN- Orbit Determination program are described. All system output is analyzed. The GEODYN Program is the nucleus of the entire GEODYN system. It is a definitive orbit and geodetic parameter estimation program capable of simultaneously processing observations from multiple arcs of multiple satellites. GEODYN has two modes of operation: (1) the data reduction mode and (2) the orbit generation mode

    An electronic Mach-Zehnder interferometer in the Fractional Quantum Hall effect

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    We compute the interference pattern of a Mach-Zehnder interferometer operating in the fractional quantum Hall effect. Our theoretical proposal is inspired by a remarkable experiment on edge states in the Integer Quantum Hall effect (IQHE). The Luttinger liquid model is solved via two independent methods: refermionization at nu=1/2 and the Bethe Ansatz solution available for Laughlin fractions. The current differs strongly from that of single electrons in the strong backscattering regime. The Fano factor is periodic in the flux, and it exhibits a sharp transition from sub-Poissonian (charge e/2) to Poissonian (charge e) in the neighborhood of destructive interferences

    Cryogenic seal remains leaktight during thermal displacement

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    Cryogenic seals protect the surfaces of a plastic member in a low-pressure system subjected to extreme temperature changes. The outer seal is an aluminum expansion ring bonded to the lens outer surface and the inner seal consists of a resin-filled aluminum U-ring bonded to the inner surface

    Parton distribution functions of proton in a light-front quark-diquark model

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    We present the parton distribution functions (PDFs) for un- polarised, longitudinally polarized and transversely polarized quarks in a proton using the light-front quark diquark model. We also present the scale evolution of PDFs and calculate axial charge and tecsor charge for uu and dd quarks at a scale of experimental findings.Comment: XXII DAE-BRNS High Energy Physics Symposium, December 12-16, 2016, University of Delhi, India; 4 pages, 1 figur
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