The correlations and anticorrelations in QPO data

Double peak kHz QPO frequencies in neutron star sources varies in time by a factor of hundreds Hz while in microquasar sources the frequencies are fixed and located at the line \nu_2 = 1.5 \nu_1 in the frequency-frequency plot. The crucial question in the theory of twin HFQPOs is whether or not those observed in neutron-star systems are essentially different from those observed in black holes. In black hole systems the twin HFQPOs are known to be in a 3:2 ratio for each source. At first sight, this seems not to be the case for neutron stars. For each individual neutron star, the upper and lower kHz QPO frequencies, \nu_2 and \nu_1, are linearly correlated, \nu_2=A \nu_1 + B, with the slope A < 1.5, i.e., the frequencies definitely are not in a 1.5 ratio. In this contribution we show that when considered jointly on a frequency-frequency plot, the data for the twin kHz QPO frequencies in several (as opposed to one) neutron stars uniquely pick out a certain preferred frequency ratio that is equal to 1.5 for the six sources examined so far.Comment: 3 pages, 1 figure, Astronomische Nachrichten, in pres

SO(2N) and SU(N) gauge theories in 2+1 dimensions

We perform an exploratory investigation of how rapidly the physics of SO(2N) gauge theories approaches its N=oo limit. This question has recently become topical because SO(2N) gauge theories are orbifold equivalent to SU(N) gauge theories, but do not have a finite chemical potential sign problem. We consider only the pure gauge theory and, because of the inconvenient location of the lattice strong-to-weak coupling 'bulk' transition in 3+1 dimensions, we largely confine our numerical calculations to 2+1 dimensions. We discuss analytic expectations in both D=2+1 and D=3+1, show that the SO(6) and SU(4) spectra do indeed appear to be the same, and show that a number of mass ratios do indeed appear to agree in the large-N limit. In particular SO(6) and SU(3) gauge theories are quite similar except for the values of the string tension and coupling, both of which differences can be readily understood.Comment: 27 pages, 9 figure

Potential role of the geriatric nutritional risk index as a novel risk factor for the development of non-valvular atrial fibrillation in patients with heart failure

PURPOSE: The geriatric nutritional risk index (GNRI) is a simple and objective nutritional assessment tool for elderly patients. Lower GNRI values are associated with a worse prognosis in heart failure with reduced ejection fraction (HFrEF). Our aim is to investigate the relationship between malnutrition and follow-up cardiovascular (CV) events in HFrEF. METHODS: A retrospective study was performed on 362 patients with HFrEF. The baseline GNRI was calculated at the first visit. The patients were divided into three groups according to the GNRI: >98, no-risk group; 92 to <= 98, low risk group; 82 to <92, moderate-to-high-risk group. The study endpoint was a composite of follow-up CV events, including all-cause mortality, non-valvular atrial fibrillation (NVAF) , need for cardioverter defibrillator (ICD) therapy, HfrEF-related hospitalizations and need for percutaneous coronary interventions (PCIs). RESULTS: Follow-up data showed that the group with moderate-to-high risk had a significantly higher incidence of NVAF, PCIs and all-cause mortality compared to other groups (p0.05). Mean GNRI value was 83.3 in NVAF patients and 101.1 in patients without NVAF (p<0.001). Kaplan Meier survival analysis showed that patients from the group with moderate-to-high risk had a significantly worse survival rate (p < 0.001). In the multivariate Cox regression analysis, the group with moderate-to-high risk (HR =3.872) and ICD implantations (HR = 4.045) were associated with increased mortality. CONCLUSION: The GNRI value may have a potential role for predicting future events, especially NVAF in patients with HfrEF

High precision Monte Carlo simulations of interfaces in the three-dimensional Ising model: a comparison with the Nambu-Goto effective string model

Motivated by the recent progress in the effective string description of the interquark potential in lattice gauge theory, we study interfaces with periodic boundary conditions in the three-dimensional Ising model. Our Monte Carlo results for the associated free energy are compared with the next-to-leading order (NLO) approximation of the Nambu-Goto string model. We find clear evidence for the validity of the effective string model at the level of the NLO truncation.Comment: 20 pages, 1 figur