Charmonium ground and excited states at finite temperature from complex Borel sum rules

Charmonium spectral functions in vector and pseudoscalar channels at finite temperature are investigated through the complex Borel sum rules and the maximum entropy method. Our approach enables us to extract the peaks corresponding to the excited charmonia, $\psi^\prime$ and $\eta_c^\prime$, as well as those of the ground states, $J/\psi$ and $\eta_c$, which has never been achieved in usual QCD sum rule analyses. We show the spectral functions in vacuum and their thermal modification around the critical temperature, which leads to the almost simultaneous melting (or peak disappearance) of the ground and excited states.Comment: 6 pages, 4 figures; published versio

Diffusion of an Inhomogeneous Vortex Tangle

The spatial diffusion of an inhomogeneous vortex tangle is studied numerically with the vortex filament model. A localized initial tangle is prepared by applying a counterflow, and the tangle is allowed to diffuse freely after the counterflow is turned off. Comparison with the solution of a generalization of the Vinen equation that takes diffusion into account leads to a very small diffusion constant, as expected from simple theoretical considerations. The relevance of this result to recent experiments on the generation and decay of superfluid turbulence at very low temperatures is discussed.Comment: 2 pages, 2 figure

Visualization of coronary plaque in type 2 diabetes mellitus patients using a new 40MHz intravascular ultrasound imaging system

SummaryBackgroundPrevious epidemiological studies demonstrated plaque vulnerability to be high in diabetic patients. iMap-intravascular ultrasound (IVUS) is a recently developed radiofrequency 40MHz IVUS imaging system for tissue characterization. This study aimed to characterize coronary plaque in target lesions of diabetic patients using iMap-IVUS.MethodsWe studied 175 treated vessels in 146 patients with stable angina pectoris and analyzed plaque components of culprit lesions by iMAP-IVUS. Patients were divided into 2 groups: non-diabetic (non-DM: 112 vessels, 93 patients) and diabetic (DM: 63 vessels, 53 patients).ResultsIn gray-scale IVUS 2D analysis, there were no differences in IVUS parameters. In 3D analysis, the DM group tended to have a larger plaque volume (p=0.07) and plaque burden (p=0.10). At minimum lumen sites, the absolute lipidic and necrotic areas (0.84±0.44mm2 vs. 0.58±0.41mm2, p<0.001, and 2.42±1.65mm2 vs. 1.46±1.76mm2, p<0.001, respectively) and percent lipidic and necrotic areas were significantly greater in the DM than in the non-DM group (8.39±3.38% vs. 5.25±2.30%, p<0.0001, and 23.65±11.54% vs. 12.99±10.71%, p<0.0001, respectively). In addition, the absolute lipidic and necrotic volumes (11.75±10.59mm3 vs. 8.18±6.24mm3, p<0.01, and 29.99±28.90mm3 vs. 19.44±19.35mm3, p<0.01, respectively) and percent lipidic and necrotic volumes were significantly greater in the DM than in the non-DM group (6.27±1.92% vs. 5.13±1.82%, p<0.0001, and 16.54±7.56% vs. 12.08±6.05%, p<0.0001, respectively).ConclusionCharacterization of coronary plaque by iMAP-IVUS in diabetic patients showed increased lipidic amount and necrotic plaque volume relative to subjects without DM

A Kelvin-wave cascade on a vortex in superfluid 4^4He at a very low temperature

A study by computer simulation is reported of the behaviour of a quantized vortex line at a very low temperature when there is continuous excitation of low-frequency Kelvin waves. There is no dissipation except by phonon radiation at a very high frequency. It is shown that non-linear coupling leads to a net flow of energy to higher wavenumbers and to the development of a simple spectrum of Kelvin waves that is insensitive to the strength and frequency of the exciting drive. The results are likely to be relevant to the decay of turbulence in superfluid $^4$He at very low temperatures