3,994 research outputs found

    Effects of Geometrical Symmetry on the Vortex Nucleation and Penetration in Mesoscopic Superconductors

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    We investigate how the geometrical symmetry affects the penetration and arrangement of vortices in mesoscopic superconductors using self-consistent Bogoliubov-de Gennes equations. We find that the entrance of the vortex happens when the current density at the hot spots reaches the depairing current density. Through determining the spatial distribution of hot spots, the geometrical symmetry of the superconducting sample influences the nucleation and entrance of vortices. Our results propose one possible experimental approach to control and manipulate the quantum states of mesoscopic superconductors with their topological geometries, and they can be easily generalized to the confined superfluids and Bose-Einstein condensates

    Are Financial Analysts' Earnings Forecasts Rational?

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    Prior studies provide conflictive findings of rational expectation tests on financial analysts forecasts based on different assumptions of loss function. Most studies using the ordinary least squares (OLS) regression tests which implicitly assume analysts face a quadratic loss function document that financial analysts do not incorporate information rationally when they form their forecasts. In contrast, other recent studies argue that financial analysts actually face a linear loss function and find no economic evidence of analysts forecasts irrationality based on the least absolute deviation (LAD) regression that implicitly assume a linear loss function. This paper re-examines the rational expectation hypothesis on earnings forecast using both loss functions. Consistent with prior studies, the findings suggest that under the OLS regression, analysts forecasts are irrational; however, no evidence of forecast irrationality is found under the LAD regression tests. Thus, prior findings of analysts forecasts inefficiency may be largely driven by a quadratic loss function

    Electrical transport across metal/two-dimensional carbon junctions: Edge versus side contacts

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    Metal/two-dimensional carbon junctions are characterized by using a nanoprobe in an ultrahigh vacuum environment. Significant differences were found in bias voltage (V) dependence of differential conductance (dI/dV) between edge- and side-contact; the former exhibits a clear linear relationship (i.e., dI/dV \propto V), whereas the latter is characterized by a nonlinear dependence, dI/dV \propto V3/2. Theoretical calculations confirm the experimental results, which are due to the robust two-dimensional nature of the carbon materials under study. Our work demonstrates the importance of contact geometry in graphene-based electronic devices

    Application of Metabolomics in Traditional Chinese Medicine Differentiation of Deficiency and Excess Syndromes in Patients with Diabetes Mellitus

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    Metabolic profiling is widely used as a probe in diagnosing diseases. In this study, the metabolic profiling of urinary carbohydrates was investigated using gas chromatography/mass spectrometry (GC/MS) and multivariate statistical analysis. The kernel-based orthogonal projections to latent structures (K-OPLS) model were established and validated to distinguish between subjects with and without diabetes mellitus (DM). The model was combined with subwindow permutation analysis (SPA) in order to extract novel biomarker information. Furthermore, the K-OPLS model visually represented the alterations in urinary carbohydrate profiles of excess and deficiency syndromes in patients with diabetes. The combination of GC/MS and K-OPLS/SPA analysis allowed the urinary carbohydrate metabolic characterization of DM patients with different traditional Chinese medicine (TCM) syndromes, including biomarkers different from non-DM patients. The method presented in this study might be a complement or an alternative to TCM syndrome research

    Lactobacillus rhamnosus GG Suppresses Meningitic E. coli K1 Penetration across Human Intestinal Epithelial Cells In Vitro and Protects Neonatal Rats against Experimental Hematogenous Meningitis

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    The purpose of this study was to examine prophylactic efficacy of probiotics in neonatal sepsis and meningitis caused by E. coli K1. The potential inhibitory effect of Lactobacillus rhamnosus GG (LGG) on meningitic E. coli K1 infection was examined by using (i) in vitro inhibition assays with E44 (a CSF isolate from a newborn baby with E. coli meningitis), and (ii) the neonatal rat model of E. coli sepsis and meningitis. The in vitro studies demonstrated that LGG blocked E44 adhesion, invasion, and transcytosis in a dose-dependent manner. A significant reduction in the levels of pathogen colonization, E. coli bacteremia, and meningitis was observed in the LGG-treated neonatal rats, as assessed by viable cultures, compared to the levels in the control group. In conclusion, probiotic LGG strongly suppresses meningitic E. coli pathogens in vitro and in vivo. The results support the use of probiotic strains such as LGG for prophylaxis of neonatal sepsis and meningitis
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