5,626 research outputs found

    The disappearance of a narrow Mg II absorption system in quasar SDSS J165501.31+260517.4

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    In this letter, we present for the first time, the discovery of the disappearance of a narrow Mg II λλ2796,2803\lambda\lambda2796,2803 absorption system from the spectra of quasar SDSS J165501.31+260517.4 (ze=1.8671z_{\rm e}=1.8671). This absorber is located at zabs=1.7877z_{\rm abs} =1.7877, and has a velocity offset of 8,423 km s−18,423\rm ~km~s^{-1} with respect to the quasar. According to the velocity offset and the line variability, this narrow Mg II λλ2796,2803\lambda\lambda2796,2803 absorption system is likely intrinsic to the quasar. Since the corresponding UV continuum emission and the absorption lines of another narrow Mg II λλ2796,2803\lambda\lambda2796,2803 absorption system at zabs=1.8656z_{\rm abs}=1.8656 are very stable, we think that the disappearance of the absorption system is unlikely to be caused by the change in ionization of absorption gas. Instead, it likely arises from the motion of the absorption gas across the line of sight

    Kinetic behavior of the general modifier mechanism of Botts and Morales with non-equilibrium binding

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    In this paper, we perform a complete analysis of the kinetic behavior of the general modifier mechanism of Botts and Morales in both equilibrium steady states and non-equilibrium steady states (NESS). Enlightened by the non-equilibrium theory of Markov chains, we introduce the net flux into discussion and acquire an expression of product rate in NESS, which has clear biophysical significance. Up till now, it is a general belief that being an activator or an inhibitor is an intrinsic property of the modifier. However, we reveal that this traditional point of view is based on the equilibrium assumption. A modifier may no longer be an overall activator or inhibitor when the reaction system is not in equilibrium. Based on the regulation of enzyme activity by the modifier concentration, we classify the kinetic behavior of the modifier into three categories, which are named hyperbolic behavior, bell-shaped behavior, and switching behavior, respectively. We show that the switching phenomenon, in which a modifier may convert between an activator and an inhibitor when the modifier concentration varies, occurs only in NESS. Effects of drugs on the Pgp ATPase activity, where drugs may convert from activators to inhibitors with the increase of the drug concentration, are taken as a typical example to demonstrate the occurrence of the switching phenomenon.Comment: 19 pages, 10 figure

    Spectral and optical properties in the antiphase stripe phase of the cuprate superconductors

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    We investigate the superconducting order parameter, the spectral and optical properties in a stripe model with spin (charge) domain-derived scattering potential VsV_{s} (VcV_{c}). We show that the charge domain-derived scattering is less effective than the spin scattering on the suppression of superconductivity. For Vs≫VcV_{s}\gg V_{c}, the spectral weight concentrates on the (π,0\pi,0) antinodal region, and a finite energy peak appears in the optical conductivity with the disappearance of the Drude peak. But for Vs≈VcV_{s}\approx V_{c}, the spectral weight concentrates on the (π/2,π/2\pi/2,\pi/2) nodal region, and a residual Drude peak exists in the optical conductivity without the finite energy peak. These results consistently account for the divergent observations in the ARPES and optical conductivity experiments in several high-TcT_c cuprates, and suggest that the "insulating" and "metallic" properties are intrinsic to the stripe state, depending on the relative strength of the spin and charge domain-derived scattering potentials.Comment: 7 pages, 4 figure

    Coexistence of the antiferromagnetic and superconducting order and its effect on spin dynamics in electron-doped high-TcT_{c} cuprates

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    In the framework of the slave-boson approach to the t−t′−t′′−Jt-t'-t''-J model, it is found that for electron-doped high-TcT_c cuprates, the staggered antiferromagnetic (AF) order coexists with superconducting (SC) order in a wide doping level ranged from underdoped to nearly optimal doping at the mean-field level. In the coexisting phase, it is revealed that the spin response is commensurate in a substantial frequency range below a crossover frequency ωc\omega_{c} for all dopings considered, and it switches to the incommensurate structure when the frequency is higher than ωc\omega_{c}. This result is in agreement with the experimental measurements. Comparison of the spin response between the coexisting phase and the pure SC phase with a dx2−y2d_{x^{2}-y^{2}}-wave pairing plus a higher harmonics term (DP+HH) suggests that the inclusion of the two-band effect is important to consistently account for both the dispersion of the spin response and the non-monotonic gap behavior in the electron-doped cuprates.Comment: 6 pages, 5 figure

    Quantum Criticality from in-situ Density Imaging

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    We perform large-scale Quantum Monte Carlo (QMC) simulations for strongly interacting bosons in a 2D optical lattice trap, and confirm an excellent agreement with the benchmarking in-situ density measurements by the Chicago group [1]. We further present a general finite temperature phase diagram both for the uniform and the trapped systems, and demonstrate how the universal scaling properties near the superfluid(SF)-to-Mott insulator(MI) transition can be observed by analysing the in-situ density profile. The characteristic temperature to find such quantum criticality is estimated to be of the order of the single-particle bandwidth, which should be achievable in the present or near future experiments. Finally, we examine the validity regime of the local fluctuation-dissipation theorem (FDT), which can be a used as a thermometry in the strongly interacting regime.Comment: 4 page

    Stage-oriented Comprehensive Acupuncture Treatment plus Rehabilitation Training for Apoplectic Hemiplegia

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    ObjectiveTo study the effect of stage-oriented comprehensive acupuncture treatment plus rehabilitation training for the recovery of apoplectic hemiplegia.MethodsThe 60 cases of acute apoplectic hemiplegia were divided randomly into the treatment and control groups with 30 in each. Based on the routine medication, acupuncture combined with modern rehabilitation techniques was applied for the treatment group, while only rehabilitation treatment for the control group. Before and three months after treatment, the evaluation was done on the motor function and daily life ability for both groups respectively with simplified Fugl-Meyer Evaluation and modified Barthel index.ResultsThe therapeutic effect of treatment group was significantly superior to that of the control group (P<0.05).ConclusionsBased on Brunnstrom's theory of six-stage in the recovery of hemiplegia, the effect of stage-oriented comprehensive acupuncture therapy combined with rehabilitation training is very good, helpful in raising the daily life ability of patients

    Synergetic Effect of Yihuo Qingyi Decoction () and Recombinant Staphylokinase in Treatment of Severe Acute Pancreatitis of Rats

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    ObjectiveTo investigate the effect of recombinant staphylokinase (r-Sak) and the Chinese medicine Yihuo Qingyi Decoction (Herbal decoction for severe acute pancreatitis) in the treatment of the severe acute pancreatitis (SAP) in rats, and to observe the synergistic effect of the two.MethodsOne hundred and sixty-two adult male SD rats with the body mass of 250–280 g were randomly divided into the following 5 groups: sham operation group (n=18), control group (n=36), Yihuo Qingyi Decoction treatment group (n=36), r-Sak treatment group (n=36), and Yihuo Qingyi Decoction plus r-Sak treatment group (n=36). The SAP ratmodel was prepared by retrograde injection of 5% sodium taurocholate into the cholangiopancreatic duct. Two days before modeling, Yihuo Qingyi Decoction was intragastrically administrated, and r-Sak was intraperitoneally injected. The survival rate within 18 h after modeling was determined. The pancreatic blood flow, the weight of ascites, and the serum amylase and lipase were investigated at 6 h, 12 h, and 18kh after modeling, and the pancreatic tissue was examined under light microscopy to see its pathological change.ResultsThe 18 h survival count of group A,B,C,D and E rats was 9,2,6,7 and 8 respectively. After r-Sak and Yihuo Qingyi Decoction intervention, the serum amylase and lipase and the weight of ascites were significantly decreased, especially in group E.18 h after modeling, the level of the serum amylase and lipase and the weight of ascites in group E was 1 100±118 U·L−1,1 000±150 U·L−1 and 13.40±1.80 g respectively, obviously lower than that of group B (P<0.05). After SAP was induced, the pancreatic blood flow showed a tendency to decrease, but the decrease extent in the treatment groups was smaller than that in the control group.18h after modeling, the pancreatic blood flow in group B and group E was 30.16±8.96 mL·100 g−1·min−1, and 129.10±42.58 mL·100 g−1·min−1 respectively, there was significant difference (P<0.05). The pathological change of the pancreatic tissue was alleviated in the treatment groups.ConclusionBoth r-Sak and Yihuo Qingyi Decoction play a beneficial role in the treatment of rat SAP and there is a synergistic effect between the two
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