5,448 research outputs found
Nuclear stopping and sideward-flow correlation from 0.35A to 200A GeV
The correlation between the nuclear stopping and the scale invariant nucleon
sideward flow at energies ranging from those available at the GSI heavy ion
synchrotron (SIS) to those at the CERN Super Proton Synchrotron (SPS) is
studied within ultrarelativistic quantum molecular dynamics (UrQMD). The
universal behavior of the two experimental observables for various colliding
systems and scale impact parameters are found to be highly correlated with each
other. As there is no phase transition mechanism involved in the UrQMD, the
correlation may be broken down by the sudden change of the bulk properties of
the nuclear matter, such as the formation of quark-gluon plasma (QGP), which
can be employed as a QGP phase transition signal in high-energy heavy ion
collisions. Furthermore, we also point out that the appearance of a breakdown
of the correlation may be a powerful tool for searching for the critical point
on the QCD phase diagram.Comment: 5 pages, 4 figure
Health Numeracy Confidence among Racial/ Ethnica Minorities in HINTS 2007: Sociodemographic, Attitudinal, and Knowledge Correlates
Health numeracy skills help people interpret health risks, and make effective medical decisions. Lower health numeracy confidence was observed for blacks and Hispanic groups than whites. Little is known about the important factors that explain racial differences in health numeracy confidence. For this study, we used a nationally representative, cross-sectional data sample of 4,610 U.S. adults from the National Cancer Institute’s 2007 Health Information National Trends Survey. Bivariate (Chi-squares) and multiple logistic regression analyses were conducted to identify the contribution factors that predict health numeracy confidence.Non-linear Fairlie decompositions were used to quantify the factor contributions to racial differences in health numeracy confidence. The priority rankings of the important factors to explain the health numeracy confidence racial and ethnic disparities are different depending on the particular racial and ethnic group. Diverse, culturally appropriate approaches are needed to improve numeracy confidence for specific racial and ethnic groups
Is the late near-infrared bump in short-hard GRB 130603B due to the Li-Paczynski kilonova?
Short-hard gamma-ray bursts (GRBs) are widely believed to be produced by the
merger of two binary compact objects, specifically by two neutron stars or by a
neutron star orbiting a black hole. According to the Li-Paczynski kilonova
model, the merger would launch sub-relativistic ejecta and a
near-infrared/optical transient would then occur, lasting up to days, which is
powered by the radioactive decay of heavy elements synthesized in the ejecta.
The detection of a late bump using the {\em Hubble Space Telescope} ({\em HST})
in the near-infrared afterglow light curve of the short-hard GRB 130603B is
indeed consistent with such a model. However, as shown in this Letter, the
limited {\em HST} near-infrared lightcurve behavior can also be interpreted as
the synchrotron radiation of the external shock driven by a wide mildly
relativistic outflow. In such a scenario, the radio emission is expected to
peak with a flux of Jy, which is detectable for current radio
arrays. Hence, the radio afterglow data can provide complementary evidence on
the nature of the bump in GRB 130603B. It is worth noting that good
spectroscopy during the bump phase in short-hard bursts can test validity of
either model above, analogous to spectroscopy of broad-lined Type Ic supernova
in long-soft GRBs.Comment: 4 pages, 2 figures, published in ApJ Lette
A novel tread model for tire modelling using experimental modal parameters
Modal parameter model acts as an analytical model of tire, because it can represent the entire tire characteristics, when applied to the tire modelling. However, without considering the effect of transfer characteristics of adjacent tread spring elements, the accuracy of modal parameter model may be limited in previous studies. Based on contact mechanics and the modal parameter model, a novel tread model is proposed considering tread transfer characteristics, and then a modified model using the modal parameters was obtained using the novel tread model. The effects of tire external characteristics were analyzed by modifying the modal parameter static vertical model. Finally, the experimental and calculated data were compared, the proposed tread model improved the accuracy of calculation. The results show that the tread transfer characteristics significantly affect contact length, i.e., by improving the predictive accuracy by 50 %, and the effect on improving the squat of tire can be ignored. The developed model may help to optimize tire modelling
Movable Fiber-Integrated Hybrid Plasmonic Waveguide on Metal Film
A waveguide structure consisting of a tapered nanofiber on a metal film is
proposed and analyzed to support highly localized hybrid plasmonic modes. The
hybrid plasmonic mode can be efficiently excited through the in-line tapered
fiber based on adiabatic conversion and collected by the same fiber, which is
very convenient in the experiment. Due to the ultrasmall mode area of plasmonic
mode, the local electromagnetic field is greatly enhanced in this movable
waveguide, which is potential for enhanced coherence light emitter
interactions, such as waveguide quantum electrodynamics, single emitter
spectrum and nonlinear optics
A supra-massive magnetar central engine for short GRB 130603B
We show that the peculiar early optical and in particular X-ray afterglow
emission of the short duration burst GRB 130603B can be explained by continuous
energy injection into the blastwave from a supra-massive magnetar central
engine. The observed energetics and temporal/spectral properties of the late
infrared bump (i.e., the "kilonova") are also found consistent with emission
from the ejecta launched during an NS-NS merger and powered by a magnetar
central engine. The isotropic-equivalent kinetic energies of both the GRB
blastwave and the kilonova are about erg, consistent
with being powered by a near-isotropic magnetar wind. However, this relatively
small value demands that most of the initial rotational energy of the magnetar
is carried away by gravitational wave
radiation. Our results suggest that (i) the progenitor of GRB 130603B would be
a NS-NS binary system, whose merger product would be a supra-massive neutron
star that lasted for about seconds; (ii) the equation-of-state of
nuclear matter would be stiff enough to allow survival of a long-lived
supra-massive neutron star, so that it is promising to detect bright
electromagnetic counterparts of gravitational wave triggers without short GRB
associations in the upcoming Advanced LIGO/Virgo era.Comment: Five pages including 1 Figure, to appear in ApJ
Totally thoracoscopic closure of ventricular septal defect without a robotically assisted surgical system: A summary of 119 cases
ObjectivesTo summarize the clinical outcomes of totally thoracoscopic closure of a ventricular septal defect (VSD).MethodsTotally thoracoscopic VSD closure was performed in 119 patients (66 boys; mean age, 7.1 ± 3.6 years). An additional 35 patients undergoing open-chest VSD closure were selected as a control group. Using 3 port incisions in the right chest, pericardiotomy, bicaval occlusion, atriotomy, and VSD closure were performed by thoracoscopy without the aid of a robotically assisted surgical system.ResultsCardiopulmonary bypass and aortic crossclamp times were 42.2 ± 9.8 and 32.5 ± 7.3 minutes, respectively. There were no deaths but 1 patient required insertion of a permanent pacemaker as a result of postoperative atrioventricular conduction block. The length of stay in the intensive care unit (11.0 ± 2.6 vs 22.9 ± 4.9 hours, P < .01) or postoperative hospital stay (4.2 ± 1.1 vs 6.6 ± 2.1 days, P < .03) in the thoracoscopic group were shorter than in the control group. The percentage of patients who required postoperative opioid analgesics in the thoracoscopic group was lower than in the control group (31.9% vs 74.2%, P < .001). Rate of blood transfusion during the operation (17.6% vs 65.7%, P = .001) and the postoperative use of opioid analgesics (31.9% vs 74.3%, P = .003) in the thoracoscopic group was lower than in the control group. Transesophageal echocardiographic analysis 4.6 ± 2.3 months after the operation showed complete closure of the defect.ConclusionsTotally thoracoscopic closure of VSD through a 3-port entry was safe and effective
- …