381 research outputs found

    Pseudo-rotations of the open annulus

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    In this paper, we study pseudo-rotations of the open annulus, \emph{i.e.} conservative homeomorphisms of the open annulus whose rotation set is reduced to a single irrational number (the angle of the pseudo-rotation). We prove in particular that, for every pseudo-rotation hh of angle ρ\rho, the rigid rotation of angle ρ\rho is in the closure of the conjugacy class of hh. We also prove that pseudo-rotations are not persistent in CrC^r topology for any r≄0r\geq 0.Comment: 25 page

    Electrochemically assisted adsorption/desorption of bentazone on activated carbon cloth

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    This paper investigates the use of electrochemical techniques for the removal of a common herbicide, bentazone, from water streams using a carbon-based electrode. Activated carbon cloth with high surface area and narrow micropores was used as electrode. For a better understanding of the process, adsorption was investigated under both open circuit and controlled polarization conditions, the latter in anodic and cathodic directions. It was found that anodic polarization enhances the kinetics of adsorption of the herbicide on the carbon cloth, the extent of which is strongly related to the applied current value. At converse, cathodic polarization induces the reversible desorption of the compound. Moreover, in-situ UV spectra recording on the solution did not show any structural change of the herbicide upon polarization, demonstrating the reversibility of the process for the regeneration of the adsorbent and the recovery of the compound. Based on these experiments, a mechanism is proposed to interpret the reversible sorption of bentazone under polarization.The authors thank Actitex, France, for kindly supplying the activated carbon cloth. COA thanks the CSIC I3P Program, co-financed by the European Social Fund, for a postdoctoral contract. Dr. Khomenko is also acknowledged for fruitful discussionsPeer reviewe

    Solvent-free ionic liquids as in situ probes for assessing the effect of ion size on the performance of electrical double layer capacitors

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    The authors thank Norit for kindly supplying the activated carbon adsorbent. COA thanks MEC, Spain, for the financial support (EX2004-0612). PoznaƄ University of Technology is also acknowledged (Project DS 32/007/2005). The help of Dr. Parra with the Modelling Software and of Dr. Khomenko in the conductivity measurements is acknowledged.Peer reviewe

    Hydroelectric System Response to Part Load Vortex Rope Excitation

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    The prediction of pressure and output power fluctuations amplitudes on Francis turbine prototype is a challenge for hydro-equipment industry since it is subjected to guarantees to ensure smooth and reliable operation of the hydro units. The European FP7 research project Hyperbole aims to setup a methodology to transpose the pressure fluctuations induced by the cavitation vortex rope on the reduced scale model to the prototype generating units. A Francis turbine unit of 444MW with a specific speed value of Μ = 0.29, is considered as case study. A SIMSEN model of the power station including electrical system, controllers, rotating train and hydraulic system with transposed draft tube excitation sources is setup. Based on this model, a frequency analysis of the hydroelectric system is performed to analyse potential interactions between hydraulic excitation sources and electrical components

    The role of pasteurella spp and of Mycoplasma bovis in respiratory diseases in young cattle

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    Lors des essais terrains d’un traitement antibiotique chez des veaux d’éle vage atteints de maladies respiratoires, la flore trachĂ©obronchique a Ă©tĂ© inven toriĂ©e Ă  diffĂ©rentes pĂ©riodes : Ă  l’arrivĂ©e, avant traitement et aprĂšs guĂ©rison. Le rĂŽle de l’association synergique Mycoplasma bovis - Pasteurella haemoly- tica Al apparaĂźt clairement. Les conditions d’élevage et la participation de certains virus (RSV) sont encore des Ă©lĂ©ments importants de la pathogĂ©nĂšse et du pronostic des bronchopneumonies infectieuses enzootiques.When we tried an antibiotic treatment on clinical trials on weaner calves with respiratory diseases, tracheobronchial flora was examined at different moments : on the day of the arrival, before treatment and after recovery. The role of the synergistic association of Mycoplasma bovis / Pasteurella haemo- lytica A1 in the development of troubles appears to be confirmed. Bad breeding conditions and the participation of a virus (RSV) are important components of pathogenesis and prognosis of bovine Endemic Infectious Broncho pneumonia

    Selective Îș Opioid Antagonists nor-BNI, GNTI and JDTic Have Low Affinities for Non-Opioid Receptors and Transporters

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    Background: Nor-BNI, GNTI and JDTic induce selective Îș opioid antagonism that is delayed and extremely prolonged, but some other effects are of rapid onset and brief duration. The transient effects of these compounds differ, suggesting that some of them may be mediated by other targets. Results: In binding assays, the three antagonists showed no detectable affinity (Ki≄10 ”M) for most non-opioid receptors and transporters (26 of 43 tested). There was no non-opioid target for which all three compounds shared detectable affinity, or for which any two shared sub-micromolar affinity. All three compounds showed low nanomolar affinity for Îș opioid receptors, with moderate selectivity over ÎŒ and ÎŽ (3 to 44-fold). Nor-BNI bound weakly to the α2C-adrenoceptor (Ki = 630 nM). GNTI enhanced calcium mobilization by noradrenaline at the α1A-adrenoceptor (EC50 = 41 nM), but did not activate the receptor, displace radioligands, or enhance PI hydrolysis. This suggests that it is a functionally-selective allosteric enhancer. GNTI was also a weak M1 receptor antagonist (KB = 3.7 ”M). JDTic bound to the noradrenaline transporter (Ki = 54 nM), but only weakly inhibited transport (IC50 = 1.1 ”M). JDTic also bound to the opioid-like receptor NOP (Ki = 12 nM), but gave little antagonism even at 30 ”M. All three compounds exhibited rapid permeation and active efflux across Caco-2 cell monolayers. Conclusions: Across 43 non-opioid CNS targets, only GNTI exhibited a potent functional effect (allosteric enhancement of α1A-adrenoceptors). This may contribute to GNTI's severe transient effects. Plasma concentrations of nor-BNI and GNTI may be high enough to affect some peripheral non-opioid targets. Nonetheless, Îș opioid antagonism persists for weeks or months after these transient effects dissipate. With an adequate pre-administration interval, our results therefore strengthen the evidence that nor-BNI, GNTI and JDTic are highly selective Îș opioid antagonists

    Elastic modulus of multi-walled carbon nanotubes produced by catalytic chemical vapour deposition

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    Carbon nanotubes (CNTs) are ideal structures for use as reinforcement fibres in composite materials, due to their extraordinary mechanical properties, in particular high Young's modulus (E∌1TPa). Usually the high value of E is taken as granted for all types of carbon CNTs. Here we demonstrate that multi-walled carbon nanotubes (MWCNTs) produced by catalytic chemical vapour deposition (CCVD) have low moduli (E<100GPa) independently of their growth conditions. We attribute this to the presence of structural defects. Additional high-temperature annealing failed to improve the mechanical properties. This study urges a better control of the growth process in order to obtain high strength CCVD grown MWCNTs suitable for reinforcement in large-scale industrial application

    Role of kappa-opioid receptors in the effects of salvinorin A and ketamine on attention in rats

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    Disruptions in perception and cognition are characteristic of psychiatric conditions such as schizophrenia. Studies of pharmacological agents that alter perception and cognition in humans might provide a better understanding of the brain substrates of these complex processes. One way to study these states in rodents is with tests that require attention and visual perception for correct performance

    Enzymatic removal of cellulose from cotton/polyester fabric blends

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    The production of light-weight polyester fabrics from a polyester/cotton blended fabric, by means of the enzymatic removal of the cellulosic part of the material, was investigated. The removal of cotton from the blended fabric yielded more than 80% of insoluble microfibrillar material by the combined action of high beating effects and cellulase hydrolysis.Other major features of this enzymatic process for converting cotton fibers into microfibrillar material are bath ratio, enzyme dosage and treatment time
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