2,184 research outputs found

    The EU as an International Actor: Lessons from the China Arms Embargo Debate

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    Much of the literature on the European Union’s development as an international actor has focused on either the institutionalisation of foreign policymaking or what type of actor the EU can be regarded as. This paper seeks to examine a dimension which has received comparatively less attention: how other actors in the international arena view the EU. Recognition is a prerequisite for the EU to become a credible international actor. Through examining the EU’s debate over lifting its China arms embargo, this paper reflects on the impact of the debate on the views of the EU held by two other significant actors – the USA and the PRC – and the implications for the EU. The literature on the arms embargo debate has tended to treat it as a case study of EU foreign policymaking or as an issue in EU-China relations. Little has been said about the broader implications for the image of the EU in the eyes of others. Through analysis of the debate’s context and subsequent developments in EU-US and EU-China relations, an evaluation is made of whether the debate can be considered as a setback for developing EU ‘actorness’ and what, if any, lessons have been learned by policymakers

    In-medium kaon and antikaon properties in the quark-meson coupling model

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    The properties of the kaon, KK, and antikaon, \kbar, in nuclear medium are studied in the quark-meson coupling (QMC) model. Employing a constituent quark-antiquark (MIT bag model) picture, their excitation energies in a nuclear medium at zero momentum are calculated within mean field approximation. The scalar, and the vector mesons are assumed to couple directly to the nonstrange quarks and antiquarks in the KK and \kbar mesons. It is demonstrated that the ρ\rho meson induces different mean field potentials for each member of the isodoublets, KK and \kbar, when they are embedded in asymmetric nuclear matter. Furthermore, it is also shown that this ρ\rho meson potential is repulsive for the K−K^- meson in matter with a neutron excess, and renders K−K^- condensation less likely to occur.Comment: Latex, 11 pages, 4 Postscript figures, a few typos which can be important for an interpretation (but not reflected in the results) are corrected, as published in (E) Phys. Lett. B 436 (1998) 45

    Sigma and omega meson propagation in a dense nuclear medium

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    The propagation of the scalar (σ\sigma) and vector (ω\omega) mesons in nuclear matter is studied in detail using the Walecka model over a wide range of densities and including the effects of a finite σ\sigma width through the inclusion of a two-pion loop. We calculate the dispersion relation and spectral functions of the σ\sigma and (transverse and longitudinal) ω\omega mesons, including the effect of σ\sigma-ω\omega mixing in matter. It is shown that the mixing effect is quite important in the propagation of the (longitudinal) ω\omega and σ\sigma mesons above normal nuclear matter density. We find that there is a two-peak structure in the spectral function of the σ\sigma channel, caused by σ\sigma-ω\omega mixing.Comment: 17 pages including 6 ps files, submitted to Phys. Lett. B. Acknowledgement is revise

    Long-term survival following traumatic brain injury: a population-based parametric survival analysis

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    <b><i>Background:</i></b> Long-term mortality may be increased following traumatic brain injury (TBI); however, the degree to which survival could be reduced is unknown. We aimed at modelling life expectancy following post-acute TBI to provide predictions of longevity and quantify differences in survivorship with the general population. <b><i>Methods:</i></b> A population-based retrospective cohort study using data from the Rochester Epidemiology Project (REP) was performed. A random sample of patients from Olmsted County, Minnesota with a confirmed TBI between 1987 and 2000 was identified and vital status determined in 2013. Parametric survival modelling was then used to develop a model to predict life expectancy following TBI conditional on age at injury. Survivorship following TBI was also compared with the general population and age- and gender-matched non-head injured REP controls. <b><i>Results:</i></b> Seven hundred and sixty nine patients were included in complete case analyses. The median follow-up time was 16.1 years (interquartile range 9.0-20.4) with 120 deaths occurring in the cohort during the study period. Survival after acute TBI was well represented by a Gompertz distribution. Victims of TBI surviving for at least 6 months post-injury demonstrated a much higher ongoing mortality rate compared to the US general population and non-TBI controls (hazard ratio 1.47, 95% CI 1.15-1.87). US general population cohort life table data was used to update the Gompertz model's shape and scale parameters to account for cohort effects and allow prediction of life expectancy in contemporary TBI. <b><i>Conclusions:</i></b> Survivors of TBI have decreased life expectancy compared to the general population. This may be secondary to the head injury itself or result from patient characteristics associated with both the propensity for TBI and increased early mortality. Post-TBI life expectancy estimates may be useful to guide prognosis, in public health planning, for actuarial applications and in the extrapolation of outcomes for TBI economic models

    Symmetric spaces of higher rank do not admit differentiable compactifications

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    Any nonpositively curved symmetric space admits a topological compactification, namely the Hadamard compactification. For rank one spaces, this topological compactification can be endowed with a differentiable structure such that the action of the isometry group is differentiable. Moreover, the restriction of the action on the boundary leads to a flat model for some geometry (conformal, CR or quaternionic CR depending of the space). One can ask whether such a differentiable compactification exists for higher rank spaces, hopefully leading to some knew geometry to explore. In this paper we answer negatively.Comment: 13 pages, to appear in Mathematische Annale

    Sydnone Cycloaddition Route to Pyrazole-Based Analogs of Combretastatin A4.

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    The combretastatins are an important class of tubulin-binding agents. Of this family, a number of compounds are potent tumor Vascular Disrupting Agents (VDAs) and have shown promise in the clinic for cancer therapy. We have developed a modular synthetic route to combretastatin analogs based on a pyrazole core through highly-regioselective alkyne cycloaddition reactions of sydnones. These compounds show modest to high potency against human umbilical vein endothelial cell proliferation. Moreover, evidence is presented that these novel VDAs have the same mode of action as CA4P and bind reversibly to ÎČ-tubulin - believed to be a key feature in avoiding toxicity. The most active compound from in vitro studies was taken forward to an in vivo model and instigated an increase in tumor cell necrosis

    Expanding available pyrazole substitution patterns by sydnone cycloaddition reactions

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    We report the use of alkynylsilanes for the regiocontrolled synthesis of pyrazoles from functionalised sydnones. The strategies outlined herein allow a range of pyrazoles to be accessed with substitution patterns that are otherwise not directly obtained with high selectivity by alkyne cycloadditions. Moreover, this study serendipitously highlighted a simple and convenient procedure for the synthesis of aryl monofluoromethyl ethers through the combination of TBAF and dichloromethane

    Deconfinement at finite chemical potential

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    In a confining, renormalisable, Dyson-Schwinger equation model of two-flavour QCD we explore the chemical-potential dependence of the dressed-quark propagator, which provides a means of determining the behaviour of the chiral and deconfinement order parameters, and low-energy pion observables. We find coincident, first order deconfinement and chiral symmetry restoration transitions at \mu_c = 375 MeV. f_\pi is insensitive to \mu until \mu \approx \mu_0 = 0.7 mu_c when it begins to increase rapidly. m_\pi is weakly dependent on \mu, decreasing slowly with \mu and reaching a minimum 6% less than its \mu=0 value at \mu=\mu_0. In a two-flavour free-quark gas at \mu=\mu_c the baryon number density would be approximately 3 \rho_0, where \rho_0=0.16 fm^{-3}; while in such a gas at \mu_0 the density is \rho_0.Comment: 11 pages, 3 figures, epsfig.sty, elsart.st
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