Critical phase of a magnetic hard hexagon model on triangular lattice

We introduce a magnetic hard hexagon model with two-body restrictions for configurations of hard hexagons and investigate its critical behavior by using Monte Carlo simulations and a finite size scaling method for discreate values of activity. It turns out that the restrictions bring about a critical phase which the usual hard hexagon model does not have. An upper and a lower critical value of the discrete activity for the critical phase of the newly proposed model are estimated as 4 and 6, respectively.Comment: 11 pages, 8 Postscript figures, uses revtex.st

Radial Transport Characteristics of Fast Ions Due to Energetic-Particle Modes inside the Last Closed-Flux Surface in the Compact Helical System

The internal behavior of fast ions interacting with magnetohydrodynamic bursts excited by energetic ions has been experimentally investigated in the compact helical system. The resonant convective oscillation of fast ions was identified inside the last closed-flux surface during an energetic-particle mode (EPM) burst. The phase difference between the fast-ion oscillation and the EPM, indicating the coupling strength between them, remains a certain value during the EPM burst and drives an anomalous transport of fast ions

Possibility of Deconfined Criticality in SU(N) Heisenberg Models at Small N

To examine the validity of the scenario of the deconfined critical phenomena, we carry out a quantum Monte Carlo simulation for the SU(N) generalization of the Heisenberg model with four-body and six-body interactions. The quantum phase transition between the SU(N) Néel and valence-bond solid phases is characterized for N=2, 3, and 4 on the square and honeycomb lattices. While finite-size scaling analysis works well up to the maximum lattice size (L=256) and indicates the continuous nature of the phase transition, a clear systematic change towards the first-order transition is observed in the estimates of the critical exponent y≡1/ν as the system size increases. We also confirm the relevance of a squared valence-bond solid field Ψ_2 for the SU(3) model

The effect of antagonism of adenosine A1 receptor against ischemia and reperfusion injury of the liver

Background: Adenosine is known to exert protective roles in hepatic ischemia and reperfusion injury, while all adenosine receptors do not play the cytoprotective roles. We have tested our hypothesis that blockage of adenosine binding to A1 receptor by its antagonist, KW3902 [8-(noradamantan-3-yl)-1,3-dipropylxanthine] attenuates hepatic ischemia-reperfusion injury. Methods: Adult female beagle dogs underwent a 2 h total hepatic vascular exclusion (THVE) with a venovenous bypass. Nontreated animals that underwent THVE with a venovenous bypass alone were used as the control (Group CT, n = 6). KW3902 was given to the animals by continuous intraportal infusion for 60 min before ischemia at a dose of 1μg/kg/min (Group KW, n = 6). Two wk survival, hemodynamics, hepatic tissue blood flow (HTBF), liver function, energy metabolism, cAMP concentration, and histopathological findings were studied. Results: Two wk animal survival was significantly improved in group KW compared with that in group CT (group CT: 16.7% versus group KW: 83.3%). HTBF, liver function, and hepatic adenine nucleotide concentration were remarkably better in group KW than group CT. In addition, cAMP concentration in group KW was maintained significantly higher than group CT. Histopathological examination revealed preservation of hepatic architecture and suppression of neutrophil infiltration into hepatic tissue in group KW. Conclusion: Administration of adenosine A1 receptor antagonist before ischemia attenuates hepatic ischemia-reperfusion injury. To elicit the beneficial effect of adenosine against ischemia and reperfusion injury of the liver, it is important to oppose adenosine A1 receptor activation