207 research outputs found

    Macroscopic quantum coherence in spinor condensates confined in an anisotropic potential

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    We investigate the macroscopic quantum coherence of a spin-1 Rb condensate confined in an anisotropic potential. Under the single-mode approximation, we show that the system can be modeled as a biaxial quantum magnet due to the interplay between the magnetic dipole-dipole interaction and the anisotropic potential. By applying a magnetic field along the hard-axis, we show that the tunneling splitting oscillates as a function of the field strength. We also propose an experimental scheme to detect the oscillatory behavior of the tunneling splitting by employing the Landau-Zener tunneling.Comment: 5 pages, 4 figure

    Mott-Hubbard Transition of Bosons in Optical Lattices with Three-body Interactions

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    In this paper, the quantum phase transition between superfluid state and Mott-insulator state is studied based on an extended Bose-Hubbard model with two- and three-body on-site interactions. By employing the mean-field approximation we find the extension of the insulating 'lobes' and the existence of a fixed point in three dimensional phase space. We investigate the link between experimental parameters and theoretical variables. The possibility to obverse our results through some experimental effects in optically trapped Bose-Einstein Condensates(BEC) is also discussed.Comment: 7 pages, 4 figures; to be appear in Phys. Rev.

    Genome and transcriptome analysis of Enterococcus faecium from intestinal colonization and Enterococcus faecium from urinary tract infection

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    IntroductionEnterococcus faecium is a common pathogen responsible for urinary tract infections (UTIs) and often establishes extensive colonization within the intestinal tract. Our aim was to assess the genomic and transcriptomic differences between colonized E. faecium without UTI (only-colonization) and colonized E. faecium causing UTI (endogenous infections).MethodWe investigated the correlation between fecal isolates from the same patient and UTI-causing isolates using PFGE and WGS, and classified fecal isolates into two groups: those that solely colonized and those associated with endogenous urinary tract infections. We characterized the genomes of colonization-only and endogenously infected isolates by Scoary GWAS, and the transcriptomes of the isolates at 3 h urine exposure to assess pathogen-related changes.ResultBased on PFGE and WGS, eight isolates of endogenously infected E. faecium and nine isolates of only-colonized E. faecium were characterized and carbon and nitrogen regulated metabolisms such as genes encoding the phosphotransferase (PTS) system were enriched in endogenously infected E. faecium. Transcriptome analysis revealed significant differences in gene expression in the PTS system, lysine synthesis, galactose metabolism and citrate import between endogenously infected and only-colonized E. faecium isolates, highlighting the important role of certain carbon regulatory genes in the colonization and survival of endogenously infected E. faecium.ConclusionIn only-colonized and endogenously infected isolates, we observed differential expression patterns of genes related to carbon metabolism and amino acids, suggesting that metabolic diversity is a strategy for isolates leading to endogenous infection

    A 28 nm 368 fJ/cycle, 0.43%/V Supply Sensitivity, FLL based RC Oscillator Featuring Positive TC Only Resistors and ΣM Based Trimming

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    This Brief presents a process-scaling-friendly frequency-locked-loop (FLL)-based RC oscillator. It features an R-R-C frequency-to-voltage converter that entails resistors with only the same-sign temperature coefficients. Together with a low-leakage switched-capacitor resistor and a delta-sigma-modulator-based trimming, our 71.8-MHz RC oscillator in 28-nm CMOS achieves a frequency inaccuracy of 77.6 ppm/0C, a 0.43%/V supply sensitivity, and an 11-psrms period jitter. The energy efficiency is 368 fJ/cycle
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