916 research outputs found

    Identifying spatial invasion of pandemics on metapopulation networks via anatomizing arrival history

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    Spatial spread of infectious diseases among populations via the mobility of humans is highly stochastic and heterogeneous. Accurate forecast/mining of the spread process is often hard to be achieved by using statistical or mechanical models. Here we propose a new reverse problem, which aims to identify the stochastically spatial spread process itself from observable information regarding the arrival history of infectious cases in each subpopulation. We solved the problem by developing an efficient optimization algorithm based on dynamical programming, which comprises three procedures: i, anatomizing the whole spread process among all subpopulations into disjoint componential patches; ii, inferring the most probable invasion pathways underlying each patch via maximum likelihood estimation; iii, recovering the whole process by assembling the invasion pathways in each patch iteratively, without burdens in parameter calibrations and computer simulations. Based on the entropy theory, we introduced an identifiability measure to assess the difficulty level that an invasion pathway can be identified. Results on both artificial and empirical metapopulation networks show the robust performance in identifying actual invasion pathways driving pandemic spread.Comment: 14pages, 8 figures; Accepted by IEEE Transactions on Cybernetic

    Remote Preparation of Mixed States via Noisy Entanglement

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    We present a practical and general scheme of remote preparation for pure and mixed state, in which an auxiliary qubit and controlled-NOT gate are used. We discuss the remote state preparation (RSP) in two important types of decoherent channel (depolarizing and dephaseing). In our experiment, we realize RSP in the dephaseing channel by using spontaneous parametric down conversion (SPDC), linear optical elements and single photon detector.Comment: 10 pages, 5 figures, submitted to PR

    Application of RetCamⅡ in the screening of neonatal fundus disease

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    AIM: To investigate the safe and reliable examination method for neonatal fundus screening.<p>METHODS: Fundus information of 2 836 neonates performed by RetCamⅡ in our hospital from January 1, 2012 to December 31, 2012 were retrospectively analyzed, including 1 625 cases(57.30%)of premature infants which were first examined 1-4 weeks after birth and 1 211 cases(42.70%)of term infants which were first examined within 4 weeks after birth.<p>RESULTS: Totally 454 cases of abnormalfundus were found, including 207 cases(12.74%)of retinopathy of prematurity(ROP), ROPⅠ in 118 cases(57%), ROPⅡ in 58 cases(28.02%), ROPⅢ in 23 cases(11.11%), ROPⅣ in 8 cases(3.86%), no case of ROPV. A total of 247(20.40%)term infants had abnormal fundus, of which 68 cases(27.53%)were developmental or hereditary disease, retinoblastoma in 1 case(0.40%), retinal hemorrhage in 102 cases(41.30%), retinal exudative changes in 68 cases(27.53%), optic atrophy in 5 cases(2.02%)and optic disc edema in 3 cases(1.21%).<p>CONCLUSION: Neonatal fundus diseases were so various and harmful that early screening should be attended to. Premature infants and term infants with high risk are treated as focus group of fundus screening and RetCamII examination is safe and effective

    Radiative transitions in charmonium from Nf=2N_f=2 twisted mass lattice QCD

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    We present a study for charmonium radiative transitions: J/ψηcγJ/\psi\rightarrow\eta_c\gamma, χc0J/Ψγ\chi_{c0}\rightarrow J/\Psi\gamma and hcηcγh_c\rightarrow\eta_c\gamma using Nf=2N_f=2 twisted mass lattice QCD gauge configurations. The single-quark vector form factors for ηc\eta_c and χc0\chi_{c0} are also determined. The simulation is performed at a lattice spacing of a=0.06666a= 0.06666 fm and the lattice size is 323×6432^3\times 64. After extrapolation of lattice data at nonzero Q2Q^2 to 0, we compare our results with previous quenched lattice results and the available experimental values.Comment: typeset with revtex, 15 pages, 11 figures, 4 table

    A Quenched Study of SU(3) Glueballs at Finite Temperature

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    Thermal properties of glueballs in SU(3) Yang-Mills theory are investigated in a large temperature range from 0.3Tc0.3T_c to 1.9Tc1.9T_c on anisotropic lattices. The glueball operators are optimized for the projection of the ground states by the variational method with a smearing scheme. Their thermal correlators are calculated in all 20 symmetry channels. It is found in all channels that the pole masses MGM_G of glueballs remain almost constant when the temperature is approaching the critical temperature TcT_c from below, and start to reduce gradually with the temperature going above TcT_c. The correlators in the 0++0^{++}, 0+0^{-+}, and 2++2^{++} channels are also analyzed based on the Breit-Wigner \emph{Ansatz} by assuming a thermal width Γ\Gamma to the pole mass ω0\omega_0 of each thermal glueball ground state. While the values of ω0\omega_0 are insensitive to TT in the whole temperature range, the thermal widths Γ\Gamma exhibit distinct behaviors at temperatures below and above TcT_c. The widths are very small (approximately few percent of ω0\omega_0 or even smaller) when TTcTT_c and reach values of roughly Γω0/2\Gamma\sim \omega_0/2 at T1.9TcT\approx 1.9T_c.Comment: 13 pages, 38 figure

    A Novel Model of Atherosclerosis in Rabbits Using Injury to Arterial Walls Induced by Ferric Chloride as Evaluated by Optical Coherence Tomography as well as Intravascular Ultrasound and Histology

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    This study aim was to develop a new model of atherosclerosis by FeCl3-induced injury to right common carotid arteries (CCAs) of rabbits. Right CCAs were induced in male New Zealand White rabbits (n = 15) by combination of a cholesterol-rich diet and FeCl3-induced injury to arterial walls. The right and left CCAs were evaluated by histology and in vivo intravascular ultrasound (IVUS) and optical coherence tomography (OCT) examinations of 24 hours (n = 3), 8 weeks (n = 6), and 12 weeks (n = 6) after injury. Each right CCA of the rabbits showed extensive white-yellow plaques. At eight and 12 weeks after injury, IVUS, OCT, and histological findings demonstrated that the right CCAs had evident eccentric plaques. Six plaques (50%) with evident positive remodeling were observed. Marked progression was clearly observed in the same plaque at 12 weeks after injury when it underwent repeat OCT and IVUS. We demonstrated, for the first time, a novel model of atherosclerosis induced by FeCl3. The model is simple, fast, inexpensive, and reproducible and has a high success rate. The eccentric plaques and remodeling of plaques were common in this model. We successfully carried out IVUS and OCT examinations twice in the same lesion within a relatively long period of time

    Microscopic resolution of superconducting electrons in ultrahigh-pressed hydrogen sulfide

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    We investigate the electronic and phonon properties of hydrogen sulfide (SH3_3) under ultrahigh pressure to elucidate the origin of its high-Tc_c superconductivity. Contrary to the prevailing belief that the metalized S-H σ\sigma bond is responsible, our analysis, based on the anisotropic Migdal-Eliashberg equation and the crystal orbital Hamilton population (COHP) calculation, reveals that the H-H σ\sigma-antibonding states play a dominant role in the large electron-phonon coupling that leads to the superconducting pairing in SH3_3. Furthermore, by partially restricting the vibration of S atoms, we demonstrate that the S-H bonds provide subsidiary contributions to the pairing interaction. These findings shed light on the importance of the previously overlooked H-H σ\sigma^* bonds in driving high-Tc_c superconductivity in SH3_3 and offer insights into the relationship between metallic H-H covalent antibonding and high-Tc_c superconductivity in other hydrogen-rich materials under high pressure.Comment: 11 pages, 9 figures, 59 reference
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