4,765 research outputs found

    Trade Credit, International Reserves and Sovereign Debt

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    We present a unified model of sovereign debt, trade credit and international reserves. Our model shows that access to short-term trade credit and gross international reserves critically affect the outcome of sovereign debt renegotiations. Whereas competitive banks do optimally lend for the accumulation of borrowed reserves that strengthen the bargaining position of borrowers, they also have incentives to restrict the supply of short-term trade credit during renegotiations. We first show that they effectively do so and then derive propositions that : I) establish the size of sovereign debt haircuts as a function of economic fundamentals and preferences ; II) predict that defaults occur during recessions rather than booms, contrary to reputation based models ; III) provide a rationale for holding costly borrowed reserves and, IV) show that the stock of borrowed international reserves tends to increase when global interest rates are low.

    Rotation and Spin in Physics

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    We delineate the role of rotation and spin in physics, discussing in order Newtonian classical physics, special relativity, quantum mechanics, quantum electrodynamics and general relativity. In the latter case, we discuss the generalization of the Kepler formula to post-Newtonian order (c2(c^{-2}) including spin effects and two-body effects. Experiments which verify the theoretical results for general relativistic spin-orbit effects are discussed as well as efforts being made to verify the spin-spin effects

    Ginsparg-Wilson Pions Scattering in a Sea of Staggered Quarks

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    We calculate isospin 2 pion-pion scattering in chiral perturbation theory for a partially quenched, mixed action theory with Ginsparg-Wilson valence quarks and staggered sea quarks. We point out that for some scattering channels, the power-law volume dependence of two pion states in nonunitary theories such as partially quenched or mixed action QCD is identical to that of QCD. Thus one can extract infinite volume scattering parameters from mixed action simulations. We then determine the scattering length for both 2 and 2+1 sea quarks in the isospin limit. The scattering length, when expressed in terms of the pion mass and the decay constant measured on the lattice, has no contributions from mixed valence-sea mesons, thus it does not depend upon the parameter, C_Mix, that appears in the chiral Lagrangian of the mixed theory. In addition, the contributions which nominally arise from operators appearing in the mixed action O(a^2 m_q) Lagrangian exactly cancel when the scattering length is written in this form. This is in contrast to the scattering length expressed in terms of the bare parameters of the chiral Lagrangian, which explicitly exhibits all the sicknesses and lattice spacing dependence allowed by a partially quenched mixed action theory. These results hold for both 2 and 2+1 flavors of sea quarks.Comment: 27 pages, 3 figures. Mistakes corrected in Eqs. (37), (42). Improved discussion in section 4 and related results in Eqs. (33), (37), (40) and (42). Added references. Version to be published in PR

    Isospin Breaking and ω\omega->ππ\pi\pi Decay

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    We study ωπ+π\omega\to\pi^+\pi^- decay up to including all orders of the chiral expansion and one-loop level of mesons in formlism of chiral constituent quark model. This G-parity forbidden decay is caused by mumdm_u\neq m_d and electromagnetic interaction of mesons. We illustrate that in the formlism both nonresonant contact interaction and ρ\rho resonance exchange contribute to this process, and the contribution from ρ\rho resonance exchange is dominant. We obtain that transition matrix element is =[(3956±280)(1697±130)i]=[-(3956\pm 280)-(1697\pm 130)i]MeV2^2, and isospin breaking parameter is mdmu=3.9±0.22m_d-m_u=3.9\pm 0.22MeV at energy scale μmω\mu\sim m_\omega.Comment: Revtex file, 16 pages, four eps figur

    Factors associated with the use of complementary and alternative medicines for prostate cancer by long-term survivors

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    © 2018 Egger et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Objective To assess whether the use of complementary and alternative medicines therapies (CAMs) for prostate cancer and/or its treatment side effects by long-term survivors is associated with selected socio-demographic, clinical, health-related quality-of-life (HRQOL) and/or psychological factors. Design, setting and participants The Prostate Cancer Care and Outcomes Study (PCOS) is a population-based cohort study of men with prostate cancer who were aged less than 70 years at diagnosis in New South Wales, Australia. Included in these analyses were men who returned a 10-year follow-up questionnaire, which included questions about CAM use. Methods Validated instruments assessed patient’s HRQOL and psychological well-being. Poisson regression with robust variance estimation was used to estimate the adjusted relative risks of current CAM use for prostate cancer according to socio-demographic, clinical, HRQOL and psychological factors. Results 996 of 1634 (61%) living PCOS participants completed the 10-year questionnaire. Of these 996 men, 168 (17%) were using CAMs for prostate cancer and 525 (53%) were using CAMs for any reason (including prostate cancer). Those using CAM for prostate cancer were more likely to be regular or occasional support group participants (vs. no participation RR = 2.02; 95%CI 1.41–2.88), born in another country (vs. Australian born RR = 1.59; 95%CI 1.17–2.16), have received androgen deprivation treatment (ADT) since diagnosis (RR = 1.60; 95%CI 1.12–2.28) or in the past two years (RR = 2.34; 95%CI 1.56–3.52). CAM use was associated with greater fear of recurrence (RR = 1.29; 95%CI 1.12–1.48), cancer-specific distress (RR = 1.15; 95%CI 1.01–1.30), cancer-specific hyperarousal (RR = 1.17; 95%CI 1.04–1.31), cancer locus of control (RR = 1.16; 95%CI 1.01–1.34) and less satisfaction with medical treatments (RR = 0.86; 95%CI 0.76–0.97), but not with intrusive thinking, cognitive avoidance, depression, anxiety or any HRQOL domains. Conclusions In this study, about one in six long term prostate cancer survivors used CAMs for their prostate cancer with use centred around ADT, country of birth, distress, cancer control, fear of recurrence and active help seeking

    Evaluation of the IDI-MRSA assay on the SmartCycler real-time PCR platform for rapid detection of MRSA from screening specimens

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    Rapid accurate detection is a prerequisite for the successful control of meticillin-resistant Staphylococcus aureus (MRSA). The IDI-MRSA real-time polymerase chain reaction (PCR) assay was designed to provide rapid results from nasal specimens collected in Stuart’s liquid transport medium. This study has evaluated the IDI-MRSA kit for use in a clinical laboratory by investigating the following parameters: (1) limits of detection (LoD), (2) performance with Amies’ gel-based transport medium, (3) ability to detect strains of MRSA in a collection representative of MRSA in Ireland since 1974 (n 113) and (4) performance in a clinical trial with swabs from nose, throat and groin/perineum sites from 202 patients. LoDs (colony-forming units per ml) of the IDI-MRSA kit, direct culture on MRSA-Select chromogenic agar (CA) and saltenrichment culture (with subculture onto CA) were 1,000 , 1,000 and 100 , respectively. LoDs with Stuart’s and Amies’ transport media were comparable. All except one of the 113 MRSA isolates were detected by the kit but, when six control strains carrying staphylococcal cassette chromosome mec (SCCmec) type IV element subtypes IVa d and SCCmec types V and VT were tested, the kit failed to detect MRSA carrying SCCmec V. The sensitivity and specificity for detection of MRSA from nose, throat and groin perineum specimens were comparable with slightly lower sensitivities from throat and groin/perineum specimens compared with nasal swabs (90%, 97%; 89%, 99%; 88%, 99%, respectively). Overall sensitivity, specificity and positive and negative predictive values for specimens from all sites were 88%, 99%, 94% and 97%, respectively. Further developments to improve the sensitivity of this highly worthwhile assay are required

    Production of Enhanced Beam Halos via Collective Modes and Colored Noise

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    We investigate how collective modes and colored noise conspire to produce a beam halo with much larger amplitude than could be generated by either phenomenon separately. The collective modes are lowest-order radial eigenmodes calculated self-consistently for a configuration corresponding to a direct-current, cylindrically symmetric, warm-fluid Kapchinskij-Vladimirskij equilibrium. The colored noise arises from unavoidable machine errors and influences the internal space-charge force. Its presence quickly launches statistically rare particles to ever-growing amplitudes by continually kicking them back into phase with the collective-mode oscillations. The halo amplitude is essentially the same for purely radial orbits as for orbits that are initially purely azimuthal; orbital angular momentum has no statistically significant impact. Factors that do have an impact include the amplitudes of the collective modes and the strength and autocorrelation time of the colored noise. The underlying dynamics ensues because the noise breaks the Kolmogorov-Arnol'd-Moser tori that otherwise would confine the beam. These tori are fragile; even very weak noise will eventually break them, though the time scale for their disintegration depends on the noise strength. Both collective modes and noise are therefore centrally important to the dynamics of halo formation in real beams.Comment: For full resolution pictures please go to http://www.nicadd.niu.edu/research/beams

    Higher meson resonances in ρπ0π0γ\rho \to \pi^0 \pi^0 \gamma and ωπ0π0γ\omega \to \pi^0 \pi^0 \gamma

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    The role of higher meson resonances with spin 1 and 2 is investigated quantitatively in the decay processes of ρπ0π0γ\rho \to \pi^0\pi^0 \gamma and ωπ0π0γ\omega \to \pi^0 \pi^0 \gamma. Among the higher resonances, we find that the f2(1270)f_2(1270) tensor meson can give a nontrivial contribution especially to the ωπ0π0γ\omega \to \pi^0 \pi^0 \gamma decay process. When the f2f_2 contribution is combined with the processes involving the vector and scalar meson intermediate states, a good agreement with the recent measurements is achieved for both decays. The effect of the f2(1270)f_2(1270) is found to be sizable at the intermediate photon energies and may be verified by precise measurements of the recoil photon spectrum of the ωπ0π0γ\omega \to \pi^0 \pi^0 \gamma decay. The dependence of the decay widths on various models for the ρ\rho-ω\omega mixing in the literature is also investigated.Comment: 16 pages, REVTeX, 6 figures, revised version, to appear in Phys. Rev.
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