3,719 research outputs found

    Correlation of mechanical factors and gallbladder pain

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    Acalculous biliary pain occurs in patients with no gallstones, but is similar to that experienced by patients with gallstones. Surgical removal of the gallbladder (GB) in these patients is only successful in providing relief of symptoms to about half of those operated on, so a reliable pain-prediction model is needed. In this paper, a mechanical model is developed for the human biliary system during the emptying phase, based on a clinical test in which GB volume changes are measured in response to a standard stimulus and a recorded pain profile. The model can describe the bile emptying behaviour, the flow resistance in the biliary ducts, the peak total stress, including the passive and active stresses experienced by the GB during emptying. This model is used to explore the potential link between GB pain and mechanical factors. It is found that the peak total normal stress may be used as an effective pain indicator for GB pain. When this model is applied to clinical data of volume changes due to Cholecystokinin stimulation and pain from 37 patients, it shows a promising success rate of 88.2% in positive pain prediction

    Soft X-ray resonant scattering study of single-crystal LaSr2_2Mn2_2O7_7

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    Soft X-ray resonant scattering studies at the Mn LII, IIIL_{\texttt{II, III}}- and the La MIV, VM_{\texttt{IV, V}}- edges of single-crystal LaSr2_2Mn2_2O7_7 are reported. At low temperatures, below TN≈160T_\texttt{N} \approx 160 K, energy scans with a fixed momentum transfer at the \emph{A}-type antiferromagnetic (0 0 1) reflection around the Mn LII, IIIL_{\texttt{II, III}}-edges with incident linear σ\sigma and π\pi polarizations show strong resonant enhancements. The splitting of the energy spectra around the Mn LII, IIIL_{\texttt{II, III}}-edges may indicate the presence of a mixed valence state, e.g., Mn3+^{3+}/Mn4+^{4+}. The relative intensities of the resonance and the clear shoulder-feature as well as the strong incident σ\sigma and π\pi polarization dependences strongly indicate its complex electronic origin. Unexpected enhancement of the charge Bragg (0 0 2) reflection at the La MIV, VM_{\texttt{IV, V}}-edges with σ\sigma polarization has been observed up to 300 K, with an anomaly appearing around the orbital-ordering transition temperature, TOO≈220T_{\texttt{OO}} \approx 220 K, suggesting a strong coupling (competition) between them.Comment: Accepted by European Physical Journal

    The controlled teleportation of an arbitrary two-atom entangled state in driven cavity QED

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    In this paper, we propose a scheme for the controlled teleportation of an arbitrary two-atom entangled state ∣ϕ>12=a∣gg>12+b∣ge>12+c∣eg>12+d∣ee>12|\phi>_{12}=a|gg>_{12}+b|ge>_{12}+c|eg>_{12}+d|ee>_{12} in driven cavity QED. An arbitrary two-atom entangled state can be teleported perfectly with the help of the cooperation of the third side by constructing a three-atom GHZ entangled state as the controlled channel. This scheme does not involve apparent (or direct) Bell-state measurement and is insensitive to the cavity decay and the thermal field. The probability of the success in our scheme is 1.0.Comment: 10 page

    Trees with Given Stability Number and Minimum Number of Stable Sets

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    We study the structure of trees minimizing their number of stable sets for given order nn and stability number α\alpha. Our main result is that the edges of a non-trivial extremal tree can be partitioned into n−αn-\alpha stars, each of size ⌈n−1n−α⌉\lceil \frac{n-1}{n-\alpha} \rceil or ⌊n−1n−α⌋\lfloor \frac{n-1}{n-\alpha}\rfloor, so that every vertex is included in at most two distinct stars, and the centers of these stars form a stable set of the tree.Comment: v2: Referees' comments incorporate

    Maximal surface group representations in isometry groups of classical Hermitian symmetric spaces

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    Higgs bundles and non-abelian Hodge theory provide holomorphic methods with which to study the moduli spaces of surface group representations in a reductive Lie group G. In this paper we survey the case in which G is the isometry group of a classical Hermitian symmetric space of non-compact type. Using Morse theory on the moduli spaces of Higgs bundles, we compute the number of connected components of the moduli space of representations with maximal Toledo invariant.Comment: v2: added due credits to the work of Burger, Iozzi and Wienhard. v3: corrected count of connected components for G=SU(p,q) (p \neq q); added due credits to the work of Xia and Markman-Xia; minor corrections and clarifications. 31 page

    BES3 time of flight monitoring system

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    A Time of Flight monitoring system has been developed for BES3. The light source is a 442-443 nm laser diode, which is stable and provides a pulse width as narrow as 50 ps and a peak power as large as 2.6 W. Two optical-fiber bundles with a total of 512 optical fibers, including spares, are used to distribute the light pulses to the Time of Flight counters. The design, operation, and performance of the system are described.Comment: 8 pages 16 figures, submitted to NI

    The upstream magnetic field of collisionless GRB shocks: constraint by Fermi-LAT observations

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    Long-lived >100 MeV emission has been a common feature of most Fermi-LAT detected gamma-ray bursts (GRBs), e.g., detected up to ~10^3s in long GRBs 080916C and 090902B and ~10^2s in short GRB 090510. This emission is consistent with being produced by synchrotron emission of electrons accelerated to high energy by the relativistic collisionless shock propagating into the weakly magnetized medium. Here we show that this high-energy afterglow emission constrains the preshock magnetic field to satisfy 1(n/1cc)^{9/8} mG<B<10^2(n/1cc)^{3/8}mG, where n is the preshock density, more stringent than the previous constraint by X-ray afterglow observations on day scale. This suggests that the preshock magnetic field is strongly amplified, most likely by the streaming of high energy shock accelerated particles.Comment: 9 pages, JCAP accepte

    Distributed phase-covariant cloning with atomic ensembles via quantum Zeno dynamics

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    We propose an interesting scheme for distributed orbital state quantum cloning with atomic ensembles based on the quantum Zeno dynamics. These atomic ensembles which consist of identical three-level atoms are trapped in distant cavities connected by a single-mode integrated optical star coupler. These qubits can be manipulated through appropriate modulation of the coupling constants between atomic ensemble and classical field, and the cavity decay can be largely suppressed as the number of atoms in the ensemble qubits increases. The fidelity of each cloned qubit can be obtained with analytic result. The present scheme provides a new way to construct the quantum communication network.Comment: 5 pages, 4 figure
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