916 research outputs found
Identifying spatial invasion of pandemics on metapopulation networks via anatomizing arrival history
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
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
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 twisted mass lattice QCD
We present a study for charmonium radiative transitions:
, and
using twisted mass lattice QCD gauge
configurations. The single-quark vector form factors for and
are also determined. The simulation is performed at a lattice
spacing of fm and the lattice size is . After
extrapolation of lattice data at nonzero 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
Thermal properties of glueballs in SU(3) Yang-Mills theory are investigated
in a large temperature range from to 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 of glueballs remain almost constant when the temperature is
approaching the critical temperature from below, and start to reduce
gradually with the temperature going above . The correlators in the
, , and channels are also analyzed based on the
Breit-Wigner \emph{Ansatz} by assuming a thermal width to the pole
mass of each thermal glueball ground state. While the values of
are insensitive to in the whole temperature range, the thermal
widths exhibit distinct behaviors at temperatures below and above
. The widths are very small (approximately few percent of or
even smaller) when and reach values of
roughly at .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
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
We investigate the electronic and phonon properties of hydrogen sulfide
(SH) under ultrahigh pressure to elucidate the origin of its high-T
superconductivity. Contrary to the prevailing belief that the metalized S-H
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 -antibonding states play a dominant
role in the large electron-phonon coupling that leads to the superconducting
pairing in SH. 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 bonds in driving high-T
superconductivity in SH and offer insights into the relationship between
metallic H-H covalent antibonding and high-T superconductivity in other
hydrogen-rich materials under high pressure.Comment: 11 pages, 9 figures, 59 reference
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