30,129 research outputs found

    Recent Trends in Hospitalization for Acute Myocardial Infarction in Beijing: Increasing Overall Burden and a Transition From ST-Segment Elevation to Non-ST-Segment Elevation Myocardial Infarction in a Population-Based Study

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    Comparable data on trends of hospitalization rates for ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) remain unavailable in representative Asian populations.To examine the temporal trends of hospitalization for acute myocardial infarction (AMI) and its subtypes in Beijing.Patients hospitalized for AMI in Beijing from January 1, 2007 to December 31, 2012 were identified from the validated Hospital Discharge Information System. Trends in hospitalization rates, in-hospital mortality, length of stay (LOS), and hospitalization costs were analyzed by regression models for total AMI and for STEMI and NSTEMI separately. In total, 77,943 patients were admitted for AMI in Beijing during the 6 years, among whom 67.5% were males and 62.4% had STEMI. During the period, the rate of AMI hospitalization per 100,000 population increased by 31.2% (from 55.8 to 73.3 per 100,000 population) after age standardization, with a slight decrease in STEMI but a 3-fold increase in NSTEMI. The ratio of STEMI to NSTEMI decreased dramatically from 6.5:1.0 to 1.3:1.0. The age-standardized in-hospital mortality decreased from 11.2% to 8.6%, with a significant decreasing trend evident for STEMI in males and females (P < 0.001) and for NSTEMI in males (P = 0.02). The rate of percutaneous coronary intervention increased from 28.7% to 55.6% among STEMI patients. The total cost for AMI hospitalization increased by 56.8% after adjusting for inflation, although the LOS decreased by 1 day.The hospitalization burden for AMI has been increasing in Beijing with a transition from STEMI to NSTEMI. Diverse temporal trends in AMI subtypes from the unselected "real-world" data in Beijing may help to guide the management of AMI in China and other developing countries

    Isospin effect in the statistical sequential decay

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    Isospin effect of the statistical emission fragments from the equilibrated source is investigated in the frame of statistical binary decay implemented into GEMINI code, isoscaling behavior is observed and the dependences of isoscaling parameters α\alpha and β\beta on emission fragment size, source size, source isospin asymmetry and excitation energies are studied. Results show that α\alpha and β\beta neither depends on light fragment size nor on source size. A good linear dependence of α\alpha and β\beta on the inverse of temperature TT is manifested and the relationship of α=4Csym[(Zs/As)12(Zs/As)22]/T\alpha=4C_{sym}[(Z_{s}/A_{s})_{1}^{2}-(Z_{s}/A_{s})_{2}^{2}]/T and β=4Csym[(Ns/As)12(Ns/As)22]/T\beta=4C_{sym}[(N_{s}/A_{s})_{1}^{2}-(N_{s}/A_{s})_{2}^{2}]/T from different isospin asymmetry sources are satisfied. The symmetry energy coefficient CsymC_{sym} extracted from simulation results is \sim 23 MeV which includes both the volume and surface term contributions, of which the surface effect seems to play a significant role in the symmetry energy.Comment: 8 pages, 8 figures; A new substantially modified version which has been accepted by the Physical Review

    Indirect exchange of magnetic impurities in zigzag graphene ribbon

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    We use quantum Monte Carlo method to study the indirect coupling between two magnetic impurities on the zigzag edge of graphene ribbon, with respect to the chemical potential μ\mu. We find that the spin-spin correlation between two adatoms located on the nearest sites in the zigzag edge are drastically suppressed around the zero-energy. As we switch the system away from half-filling, the antiferromagnetic correlation is first enhanced and then decreased. If the two adatoms are adsorbed on the sites belonging to the same sublattice, we find similar behavior of spin-spin correlation except for a crossover from ferromagnetic to antiferromagentic correlation in the vicinity of zero-energy. We also calculated the weight of different components of d-electron wave function and local magnet moment for various values of parameters, and all the results are consistent with those of spin-spin correlation between two magnetic impurities.Comment: 3 pages, 4 figures, conference proceedin

    The roles of deformation and orientation in heavy-ion collisions induced by light deformed nuclei at intermediate energy

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    The reaction dynamics of axisymmetric deformed 24^{24}Mg + 24^{24}Mg collisions have been investigated systematically by an isospin-dependent quantum molecular dynamics (IDQMD) model. It is found that different deformations and orientations result in apparently different properties of reaction dynamics. We revealed that some observables such as nuclear stopping power (RR), multiplicity of fragments, and elliptic flow are very sensitive to the initial deformations and orientations. There exists an eccentricity scaling of elliptic flow in central body-body collisions with different deformations. In addition, the tip-tip and body-body configurations turn out to be two extreme cases in central reaction dynamical process.Comment: 5 pages, 7 figures, to appear in Physical Review C (Rapid Communication

    Hard photon flow and photon-photon correlation in intermediate energy heavy-ion collisions

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    Hard photons emitted from energetic heavy ion collisions are very interesting since they do not experience nuclear interaction, and therefore they are useful to explore properties of nuclear matter. We investigated hard photon production and its properties in intermediate energy heavy-ion collisions with the help of the Blotzmann-Uehling-Ulenbeck model. Two components of hard photons are discussed: direct and thermal. The positive directed flow parameter and negative elliptic flow parameter of direct photons are demonstrated and they are anti-correlated to the flows of free protons. The dependencies of hard photon production and anisotropic parameters on impact parameter, beam energy, nuclear equation of state and symmetry energy are also discussed. Furthermore, we investigated the two-photon momentum correlation function from which the space-time structure information of the photon source could be extracted as well as the two-photon azimuthal correlation which could provide another good method to determine the elliptic flow parameter v2v_{2} of direct hard photons.Comment: 13 pages, 18 figure

    Isoscaling in the Lattice Gas Model

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    The isoscaling behavior is investigated using the isotopic/isobaric yields from the equilibrated thermal source which is prepared by the lattice gas model for lighter systems with A = 36. The isoscaling parameters α\alpha and -β\beta are observed to drop with temperature. The difference of neutron and proton chemical potential shows a turning point around 5 MeV where the liquid gas phase transition occurs in the model. The relative free neutron or proton density shows a nearly linear relation with the N/Z (neutron to proton ratio) of system and the isospin fractionation is observed.Comment: 5 figures, 5 pages; the final version to appear in Phys Rev
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