Cluster Analysis of the Ising Model and Universal Finite-Size Scaling

The recent progress in the study of finite-size scaling (FSS) properties of the Ising model is briefly reviewed. We calculate the universal FSS functions for the Binder parameter $g$ and the magnetization distribution function $p(m)$ for the Ising model on $L_1 \times L_2$ two-dimensional lattices with tilted boundary conditions. We show that the FSS functions are universal for fixed sets of the aspect ratio $L_1/L_2$ and the tilt parameter. We also study the percolating properties of the Ising model, giving attention to the effects of the aspect ratio of finite systems. We elucidate the origin of the complex structure of $p(m)$ for the system with large aspect ratio by the multiple-percolating-cluster argument.Comment: 11 pages including 6 eps figures, elsart.sty, to appear in Physica

Shape Effects of Finite-Size Scaling Functions for Anisotropic Three-Dimensional Ising Models

The finite-size scaling functions for anisotropic three-dimensional Ising models of size $L_1 \times L_1 \times aL_1$ ($a$: anisotropy parameter) are studied by Monte Carlo simulations. We study the $a$ dependence of finite-size scaling functions of the Binder parameter $g$ and the magnetization distribution function $p(m)$. We have shown that the finite-size scaling functions for $p(m)$ at the critical temperature change from a two-peak structure to a single-peak one by increasing or decreasing $a$ from 1. We also study the finite-size scaling near the critical temperature of the layered square-lattice Ising model, when the systems have a large two-dimensional anisotropy. We have found the three-dimensional and two-dimensional finite-size scaling behavior depending on the parameter which is fixed; a unified view of 3D and 2D finite-size scaling behavior has been obtained for the anisotropic 3D Ising models.Comment: 6 pages including 11 eps figures, RevTeX, to appear in J. Phys.

Finite-size scaling for the Ising model on the Moebius strip and the Klein bottle

We study the finite-size scaling properties of the Ising model on the Moebius strip and the Klein bottle. The results are compared with those of the Ising model under different boundary conditions, that is, the free, cylindrical, and toroidal boundary conditions. The difference in the magnetization distribution function $p(m)$ for various boundary conditions is discussed in terms of the number of the percolating clusters and the cluster size. We also find interesting aspect-ratio dependence of the value of the Binder parameter at $T=T_c$ for various boundary conditions. We discuss the relation to the finite-size correction calculations for the dimer statistics.Comment: 4 pages including 5 eps figures, RevTex, to appear in Phys. Rev. Let

Newly Diagnosed Atrial Fibrillation in Acute Myocardial Infarction

[Background] It remains controversial whether long‐term clinical impact of newly diagnosed atrial fibrillation (AF) in the acute phase of acute myocardial infarction (AMI) is different from that of prior AF diagnosed before the onset of AMI. [Methods and Results] The current study population from the CREDO‐Kyoto AMI (Coronary Revascularization Demonstrating Outcome Study in Kyoto Acute Myocardial Infarction) Registry Wave‐2 consisted of 6228 patients with AMI who underwent percutaneous coronary intervention. The baseline characteristics and long‐term clinical outcomes were compared according to AF status (newly diagnosed AF: N=489 [7.9%], prior AF: N=589 [9.5%], and no AF: N=5150 [82.7%]). Median follow‐up duration was 5.5 years. Patients with newly diagnosed AF and prior AF had similar baseline characteristics with higher risk profile than those with no AF including older age and more comorbidities. The cumulative 5‐year incidence of all‐cause death was higher in newly diagnosed AF and prior AF than no AF (38.8%, 40.7%, and 18.7%, P<0.001). The adjusted hazard ratios (HRs) for mortality of newly diagnosed AF and prior AF relative to no AF remained significant with similar magnitude (HR, 1.31; 95% CI, 1.12–1.54; P<0.001, and HR, 1.32; 95% CI, 1.14–1.52; P<0.001, respectively). The cumulative 5‐year incidence of stroke decreased in the order of newly diagnosed AF, prior AF and no AF (15.5%, 12.9%, and 6.3%, respectively, P<0.001). The higher adjusted HRs of both newly diagnosed AF and prior AF relative to no AF were significant for stroke, with a greater risk of newly diagnosed AF than that of prior AF (HR, 2.05; 95% CI, 1.56–2.69; P<0.001, and HR, 1.33; 95% CI, 1.00–1.78; P=0.048, respectively). The higher stroke risk of newly diagnosed AF compared with prior AF was largely driven by the greater risk within 30 days. The higher adjusted HRs of newly diagnosed AF and prior AF relative to no AF were significant for heart failure hospitalization (HR, 1.73; 95% CI, 1.35–2.22; P<0.001, and HR, 2.23; 95% CI, 1.82–2.74; P<0.001, respectively) and major bleeding (HR, 1.46; 95% CI, 1.23–1.73; P<0.001, and HR, 1.36; 95% CI, 1.15–1.60; P<0.001, respectively). [Conclusions] Newly diagnosed AF in AMI had risks for mortality, heart failure hospitalization, and major bleeding higher than no AF, and comparable to prior AF. The risk of newly diagnosed AF for stroke might be higher than that of prior AF

Effect of Heart Failure on Long‐Term Clinical Outcomes After Percutaneous Coronary Intervention Versus Coronary Artery Bypass Grafting in Patients With Severe Coronary Artery Disease

[Background] Heart failure might be an important determinant in choosing coronary revascularization modalities. There was no previous study evaluating the effect of heart failure on long‐term clinical outcomes after percutaneous coronary intervention (PCI) relative to coronary artery bypass grafting (CABG). [Methods and Results] Among 14 867 consecutive patients undergoing first coronary revascularization with PCI or isolated CABG between January 2011 and December 2013 in the CREDO‐Kyoto PCI/CABG registry Cohort‐3, we identified the current study population of 3380 patients with three‐vessel or left main coronary artery disease, and compared clinical outcomes between PCI and CABG stratified by the subgroup based on the status of heart failure. There were 827 patients with heart failure (PCI: N=511, and CABG: N=316), and 2553 patients without heart failure (PCI: N=1619, and CABG: N=934). In patients with heart failure, the PCI group compared with the CABG group more often had advanced age, severe frailty, acute and severe heart failure, and elevated inflammatory markers. During a median 5.9 years of follow‐up, there was a significant interaction between heart failure and the mortality risk of PCI relative to CABG (interaction P=0.009), with excess mortality risk of PCI relative to CABG in patients with heart failure (HR, 1.75; 95% CI, 1.28–2.42; P<0.001) and no excess mortality risk in patients without heart failure (HR, 1.04; 95% CI, 0.80–1.34; P=0.77). [Conclusions] There was a significant interaction between heart failure and the mortality risk of PCI relative to CABG with excess risk in patients with heart failure and neutral risk in patients without heart failure

Finite-size scaling for the Ising model on the Moebius strip and the Klein bottle

To appear in Phys. Rev. LettConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal