348 research outputs found

    Chemo- and enantioselective sulfoxidation of bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) into chiral BEDT-TTF-sulfoxide

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    Selective sulfoxidation of BEDT-TTF (bis(ethylenedithio)-tetrathiafulvalene) with enantiopure (camphoryl-sulfonyl)oxaziridine derivatives provided the inner monosulfoxide, as demonstrated using single crystal X-ray analysis, with an enantiomeric excess of 44% (up to 74% after recrystallization)

    Universality of the Anderson transition with the quasiperiodic kicked rotor

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    We report a numerical analysis of the Anderson transition in a quantum-chaotic system, the quasiperiodic kicked rotor with three incommensurate frequencies. It is shown that this dynamical system exhibits the same critical phenomena as the truly random 3D-Anderson model. By taking proper account of systematic corrections to one-parameter scaling, the universality of the critical exponent is demonstrated. Our result ν=1.59±0.01\nu = 1.59 \pm 0.01 is in perfect agreement with the value found for the Anderson model.Comment: 4 figures, 3 tables (published version

    Symmetry Violation of Quantum Multifractality: Gaussian fluctuations versus Algebraic Localization

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    Quantum multifractality is a fundamental property of systems such as non-interacting disordered systems at an Anderson transition and many-body systems in Hilbert space. Here we discuss the origin of the presence or absence of a fundamental symmetry related to this property. The anomalous multifractal dimension Δq\Delta_q is used to characterize the structure of quantum states in such systems. Although the multifractal symmetry relation \mbox{Δq=Δ1q\Delta_q=\Delta_{1-q}} is universally fulfilled in many known systems, recently some important examples have emerged where it does not hold. We show that this is the result of two different mechanisms. The first one was already known and is related to Gaussian fluctuations well described by random matrix theory. The second one, not previously explored, is related to the presence of an algebraically localized envelope. While the effect of Gaussian fluctuations can be removed by coarse graining, the second mechanism is robust to such a procedure. We illustrate the violation of the symmetry due to algebraic localization on two systems of very different nature, a 1D Floquet critical system and a model corresponding to Anderson localization on random graphs.Comment: Closest to published versio

    Assessment of the usefulness of performing bacterial identification and antimicrobial susceptibility testing 24 h a day in a clinical microbiology laboratory

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    The impact of inoculating agar media with positive blood cultures and of performing bacterial identification and antimicrobial susceptibility testing (AST) for positive urine cultures, blood cultures and certain fluid cultures after day hours (night service (NS)) was evaluated in a clinical microbiology laboratory. The impact of the NS was assessed in terms of decreases in the delays from the time of sampling to the time at which results became available and of the consequences for patient management and antimicrobial treatment. Two major benefits were obtained: initiation of earlier appropriate treatment, and change to a reduced-spectrum but still efficient regimen. The hours of laboratory testing and the availability and transmission of results to the clinical staff were recorded. Concurrently, these hours were estimated as though laboratory tests had been performed in the absence of NS. Reductions in delay were defined as the differences between the hours actually spent and the estimated hours. Economic concerns were also considered. Overall, 430 samples for which an identification and/or AST were performed during the NS were included in the study. The NS led to the implementation of earlier appropriate therapy in 97 cases (22.6%), and to the change to reduced-spectrum but still efficient regimens in 23 additional cases (5.3%). In conclusion, there appeared to be benefits from a system providing bacterial identification and AST overnight, but a study of the cost-effectiveness of the NS would be useful to back up this observation

    A case of Ureaplasma parvum meningitis in an adult after transphenoidal ablation of craniopharyngioma

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    We report the case of a Ureaplasma parvum meningitis in an immunocompetent patient, 17 days after surgical ablation of a craniopharyngioma. Presence of U. parvum in the cerebrospinal fluid was assessed by 16S rDNA sequencing and U. parvum specific PCR. This article details a surprising complication in an adult of a transphenoidal surgery for ablation of a craniopharyngioma. This is the first case, to our knowledge, of U. parvum meningitis in an adult patient

    Fine properties of self-similar solutions of the Navier-Stokes equations

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    We study the solutions of the nonstationary incompressible Navier--Stokes equations in Rd\R^d, d2d\ge2, of self-similar form u(x,t)=1tU(xt)u(x,t)=\frac{1}{\sqrt t}U\bigl(\frac{x}{\sqrt t}\bigr), obtained from small and homogeneous initial data a(x)a(x). We construct an explicit asymptotic formula relating the self-similar profile U(x)U(x) of the velocity field to its corresponding initial datum a(x)a(x)

    High prevalence of closely-related Acinetobacter baumannii in pets according to a multicentre study in veterinary clinics, Reunion Island

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    Our objective was to study the carriage of Acinetobacter baumannii (AB) in pets in Reunion Island (RI), a French territory in Indian Ocean. Overall, 138 pets were sampled (rectum, mouth, wounds if applicable) in 9 veterinary clinics (VC). The prevalence of AB carriage was 6.5% (95%CI; 2.4, 10.6) and 9 carriers were identified from 4 VC. Hospitalization in a VC and antimicrobial treatment administered within the 15 preceding days were significantly associated with AB carriage (P<0.01 and P<0.05, respectively). Despite the VC in which animals have been sampled were located all around RI, most isolates (8/9) were closely-related (>90% similarity by pulsed-field gel electrophoresis). Additional studies are needed to improve the understanding about interactions between the different reservoirs of AB in RI
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