109 research outputs found

    The short-time critical behaviour of the Ginzburg-Landau model with long-range interaction

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    The renormalisation group approach is applied to the study of the short-time critical behaviour of the dd-dimensional Ginzburg-Landau model with long-range interaction of the form pσspspp^{\sigma} s_{p}s_{-p} in momentum space. Firstly the system is quenched from a high temperature to the critical temperature and then relaxes to equilibrium within the model A dynamics. The asymptotic scaling laws and the initial slip exponents θ\theta^{\prime} and θ\theta of the order parameter and the response function respectively, are calculated to the second order in ϵ=2σd\epsilon=2\sigma-d.Comment: 18 pages, 4 figures, 1 tabl

    Exploratory Test Agents for Stateful Software Systems

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    The adequate testing of stateful software systems is a hard and costly activity. Failures that result from complex stateful interactions can be of high impact, and it can be hard to replicate failures resulting from erroneous stateful interactions. Addressing this problem in an automatic way would save cost and time and increase the quality of software systems in the industry. In this paper, we propose an approach that uses agents to explore software systems with the intention to find faults and gain knowledge

    Driven Heisenberg Magnets: Nonequilibrium Criticality, Spatiotemporal Chaos and Control

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    We drive a dd-dimensional Heisenberg magnet using an anisotropic current. The continuum Langevin equation is analysed using a dynamical renormalization group and numerical simulations. We discover a rich steady-state phase diagram, including a critical point in a new nonequilibrium universality class, and a spatiotemporally chaotic phase. The latter may be `controlled' in a robust manner to target spatially periodic steady states with helical order.Comment: 7 pages, 2 figures. Published in Euro. Phys. Let

    Drived diffusion of vector fields

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    A model for the diffusion of vector fields driven by external forces is proposed. Using the renormalization group and the ϵ\epsilon-expansion, the dynamical critical properties of the model with gaussian noise for dimensions below the critical dimension are investigated and new transport universality classes are obtained.Comment: 11 pages, title changed, anisotropic diffusion further discussed and emphasize

    Chemical structure of methylmethacrylate-2-[2′,3′,5′-triiodobenzoyl]oxoethyl methacrylate copolymer, radio-opacity, in vitro and in vivo biocompatibility

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    The properties of copolymers (physical, chemical, biocompatibility, etc.) depend on their chemical structure and microstructural characteristics. We have prepared radio-opaque polymers based on the copolymers of methyl methacrylate (MMA) and 2-[2′,3′,5′-triiodobenzoyl]oxoethyl methacrylate (TIBOM). The copolymerization reaction between TIBOM and MMA showed that the reactivity ratios were r1 = 0.00029 and r2 = 1.2146. The composition diagram is typical for a practically non-homopolymerizable monomer (TIBOM) and a very reactive monomer (MMA). The copolymers were analyzed on an X-ray microcomputed tomograph and they proved to be radio-opaque even at low concentrations of TIBOM. The biocompatibility was tested both in vitro (with J774.2 macrophage and SaOS-2 osteoblast like cells) and in vivo in the rat. These materials were found to be non-toxic and were well tolerated by the organism. These combined results led to the suggestion that this type of polymer could be used as dental or bone cements in place of barium or zirconium particles, which are usually added to provide X-ray opacity

    Soft capacitor fibers using conductive polymers for electronic textiles

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    A novel, highly flexible, conductive polymer-based fiber with high electric capacitance is reported. In its crossection the fiber features a periodic sequence of hundreds of conductive and isolating plastic layers positioned around metallic electrodes. The fiber is fabricated using fiber drawing method, where a multi-material macroscopic preform is drawn into a sub-millimeter capacitor fiber in a single fabrication step. Several kilometres of fibers can be obtained from a single preform with fiber diameters ranging between 500um -1000um. A typical measured capacitance of our fibers is 60-100 nF/m and it is independent of the fiber diameter. For comparison, a coaxial cable of the comparable dimensions would have only ~0.06nF/m capacitance. Analysis of the fiber frequency response shows that in its simplest interrogation mode the capacitor fiber has a transverse resistance of 5 kOhm/L, which is inversely proportional to the fiber length L and is independent of the fiber diameter. Softness of the fiber materials, absence of liquid electrolyte in the fiber structure, ease of scalability to large production volumes, and high capacitance of our fibers make them interesting for various smart textile applications ranging from distributed sensing to energy storage

    Coulomb Effects on Electromagnetic Pair Production in Ultrarelativistic Heavy-Ion Collisions

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    We discuss the implications of the eikonal amplitude on the pair production probability in ultrarelativistic heavy-ion transits. In this context the Weizs\"acker-Williams method is shown to be exact in the ultrarelativistic limit, irrespective of the produced particles' mass. A new equivalent single-photon distribution is derived which correctly accounts for the Coulomb distortions. As an immediate application, consequences for unitarity violation in photo-dissociation processes in peripheral heavy-ion encounters are discussed.Comment: 13 pages, 4 .eps figure

    Aryloxymaleimides for cysteine modification, disulfide bridging and the dual functionalization of disulfide bonds

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    Tuning the properties of maleimide reagents holds significant promise in expanding the toolbox of available methods for bioconjugation. Herein we describe aryloxymaleimides which represent 'next generation maleimides' of attenuated reactivity, and demonstrate their ability to enable new methods for protein modification at disulfide bonds

    One hundred and twelve infected arthroplasties treated with ‘DAIR’ (debridement, antibiotics and implant retention): antibiotic duration and outcome

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    OBJECTIVES: We describe treatment failure rates by antibiotic duration for prosthetic joint infection (PJI) managed with debridement, antibiotics and implant retention (DAIR). METHODS: We retrospectively collected data from all the cases of PJI that were managed with DAIR over a 5 year period. Surgical debridement, microbiological sampling, early intravenous antibiotics and prolonged oral follow-on antibiotics were used. RESULTS: One hundred and twelve cases of PJI were identified. Twenty infections (18%) recurred during a mean follow-up of 2.3 years. The mean duration of antibiotic use was 1.5 years. Failure was more common after arthroscopic debridement, for previously revised joints and for Staphylococcus aureus infection. There were 12 failures after stopping antibiotics and 8 while on antibiotics [hazard ratio (HR) = 4.3, 95% confidence interval (CI) 1.4-12.8, P = 0.01]. However, during the first 3 months of follow-up, there were eight failures after stopping antibiotics and two while on antibiotics (HR = 7.0, 95% CI 1.5-33, P = 0.015). The duration of antibiotic therapy prior to stopping did not predict outcome. CONCLUSIONS: PJI may be managed by DAIR. The risk of failure with this strategy rises after stopping oral antibiotics, but lengthening antibiotic therapy may simply postpone, rather than prevent, failure
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