1,634 research outputs found

    Patching task-level robot controllers based on a local µ-calculus formula

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    We present a method for mending strategies for GR(1) specifications. Given the addition or removal of edges from the game graph describing a problem (essentially transition rules in a GR(1) specification), we apply a µ-calculus formula to a neighborhood of states to obtain a “local strategy” that navigates around the invalidated parts of an original synthesized strategy. Our method may thus avoid global resynthesis while recovering correctness with respect to the new specification. We illustrate the results both in simulation and on physical hardware for a planar robot surveillance task

    In-Situ absolute phase detection of a microwave field via incoherent fluorescence

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    Measuring the amplitude and the absolute phase of a monochromatic microwave field at a specific point of space and time has many potential applications, including precise qubit rotations and wavelength quantum teleportation. Here we show how such a measurement can indeed be made using resonant atomic probes, via detection of incoherent fluorescence induced by a laser beam. This measurement is possible due to self-interference effects between the positive and negative frequency components of the field. In effect, the small cluster of atoms here act as a highly localized pick-up coil, and the fluorescence channel acts as a transmission line.Comment: 13 pages, 5 figure

    Gaussian approximation for finitely extensible bead-spring chains with hydrodynamic interaction

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    The Gaussian Approximation, proposed originally by Ottinger [J. Chem. Phys., 90 (1) : 463-473, 1989] to account for the influence of fluctuations in hydrodynamic interactions in Rouse chains, is adapted here to derive a new mean-field approximation for the FENE spring force. This "FENE-PG" force law approximately accounts for spring-force fluctuations, which are neglected in the widely used FENE-P approximation. The Gaussian Approximation for hydrodynamic interactions is combined with the FENE-P and FENE-PG spring force approximations to obtain approximate models for finitely-extensible bead-spring chains with hydrodynamic interactions. The closed set of ODE's governing the evolution of the second-moments of the configurational probability distribution in the approximate models are used to generate predictions of rheological properties in steady and unsteady shear and uniaxial extensional flows, which are found to be in good agreement with the exact results obtained with Brownian dynamics simulations. In particular, predictions of coil-stretch hysteresis are in quantitative agreement with simulations' results. Additional simplifying diagonalization-of-normal-modes assumptions are found to lead to considerable savings in computation time, without significant loss in accuracy.Comment: 26 pages, 17 figures, 2 tables, 75 numbered equations, 1 appendix with 10 numbered equations Submitted to J. Chem. Phys. on 6 February 200

    Vancomycin for controlling contamination of selective Kirchner’s liquid medium in the culture of gastric lavage for tubercle bacilli

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    Gastric lavage (GL) was collected for culture of tubercle bacilli from children too young to expectorate sputum. The selective Kirchner’s liquid medium (SKLM), routinely used as one of the media for culture of all extrapulmonary specimens, was found to often get contaminated when cultured with GL. We have shown that vancomycin at a concentration of 10 mg/l successfully reduced the contamination from about 60 to 20 per cent, and enhanced the Isolation rate of tubercle bacilli from 3 to 6 per cent. Decontamination of the liquid culture before subculture on solid medium also helped to reduce the contamination rate. Vancomycin was found to be an effective selective drug for use In the Kirchner’s liquid medium for culture of tubercle bacilli

    Acoustical-Mode-Driven Electron-Phonon Coupling in Transition-Metal Diborides

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    We show that the electron-phonon coupling in the transition-metal diborides NbB2 and TaB2 is dominated by the longitudinal acoustical (LA) mode, in contrast to the optical E_{2g} mode dominated coupling in MgB2. Our ab initio results, described in terms of phonon dispersion, linewidth, and partial electron-phonon coupling along Gamma to A, also show that (i) NbB2 and TaB2 have a relatively weak electron-phonon coupling, (ii) the E_{2g} linewidth is an order of magnitude larger in MgB2 than in NbB2 or TaB2, (iii) the E_{2g} frequency in NbB2 and TaB2 is considerably higher than in MgB2, and (iv) the LA frequency at A for TaB2 is almost half of that of MgB2 or NbB2.Comment: 4 pages, 4 figures, and 1 tabl

    SbCl5—wet acetonitrile: a new system for chemoselective O-desilylation

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    Abstract—A new efficient method for deprotection of TBDMS derivatives of phenols, primary alcohols, carboxylic acids and secondary amines, consisting of SbCl5 and MeCN with 0.1% water (w/v), is reported. It effects inter alia desilylation of a CH2OTBDMS group in the presence of a ketal function

    Measurement of the mass of the τ lepton

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    The mass of the τ lepton has been measured at the Beijing Electron-Positron Collider using the Beijing Spectrometer. A search near threshold for e^+e^-→τ^+τ^- was performed. Candidate events were identified by requiring that one τ decay via τ→eνν¯, and the other via τ→μνν¯. The mass value, obtained from a fit to the energy dependence of the τ^+τ^- cross section, is m_τ=1776.9_(-0.5)^(+0.4)±0.2 MeV

    Meta-analysis demonstrates Gly482Ser variant of PPARGC1A is associated with components of metabolic syndrome within Asian populations.

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    To determine the association of peroxisome proliferator activated receptor gamma coactivator 1 Gly482Ser variant with components of metabolic syndrome. Materials and methods:- A systematic search was carried out using Web of Science, PubMed, EMBASE and the Cochrane library using the key words: Peroxisome proliferator activator receptor gamma coactivator 1, PPARGC1A, PGC-1, PGC-1alpha, and PGC1alpha alone or with polymorphism, Gly482Ser and rs8192678. Results:- Data from 19 articles generated 28 separate data sets. Under the recessive model fasting plasma glucose was significantly lower in AA genotypes when compared to GG+GA in the total sample group and in non-Asian group (p[less than].001). The AA genotype showed significantly lower levels of total cholesterol compared to GG+GA genotype using the recessive model with the non-Asian group (p[less than].05). Under the dominant model, body mass index of the GG genotype was significantly higher in Asian subgroups (p[less than].05). Conclusion:- PPARGC1A Gly482Ser variant impacts differently in Asian population groups
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