The Effect of Lower and Higher Calorie Meal on the Parameters of Ventricular Repolarization in Healthy Subjects

BACKGROUND: Cardiovascular modulation following meal consumption has been known. Little and conflicting data is present regarding electrocardiographic QT and QTc intervals after a meal, and status of ventricular repolarization following meal is not known comprehensively. AIM: To inquire the electrocardiographic status of ventricular repolarisation thoroughly after lower and higher calorie meal consumption in a comparative manner. METHODS: A group of 61 healthy individuals were studied before and after lunch. They were divided into two groups according to the calorie consumed (higher calorie and lower calorie; median 1580 and 900 kcals, respectively). Calorie consumed was estimated using dietary guidelines. Data was collected from 12-lead ECG both in a fasted state and 2nd postprandial hour for each participant. Parameters of ventricular repolarization, namely, JTp, Tp-e, QT, QTc intervals and their ratios, as well as RR intervals, were compared between fasted and postprandial states for every participant. RESULTS: Tp-e and QTc intervals, and Tp-e/QTc ratio do not significantly change after both higher- and lower-calorie meals. JTp and QT intervals significantly shorten in both groups, regardless of the calorie consumed. While JTp shows a positive correlation with RR interval both before and after a meal in lower calorie intake group, no correlation was found with RR interval after a meal in higher calorie group. Logistic regression analysis revealed that higher calorie intake during a meal is a predictor for greater shortening in JTp and QT, compared to lower calorie meal. CONCLUSION: Our study may guide future studies on ventricular repolarisation, particularly those conducted on various disease conditions or drug effect of cardiac electrophysiology

Observation of a new Xi(b) baryon

The first observation of a new b baryon via its strong decay into Xi(b)^- pi^+ (plus charge conjugates) is reported. The measurement uses a data sample of pp collisions at sqrt(s) = 7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 5.3 inverse femtobarns. The known Xi(b)^- baryon is reconstructed via the decay chain Xi(b)^- to J/psi Xi^- to mu^+ mu^- Lambda^0 pi^-, with Lambda^0 to p pi^-. A peak is observed in the distribution of the difference between the mass of the Xi(b)^- pi^+ system and the sum of the masses of the Xi(b)^- and pi^+, with a significance exceeding five standard deviations. The mass difference of the peak is 14.84 +/- 0.74 (stat.) +/- 0.28 (syst.) MeV. The new state most likely corresponds to the J^P=3/2^+ companion of the Xi(b).Comment: Submitted to Physical Review Letter

Measurements of inclusive W and Z cross sections in pp collisions at root s=7 TeV

This is the pre-print version of the Published Article, which can be accessed from the link below - Copyright @ 2011 Springer VerlagMeasurements of inclusive W and Z boson production cross sections in pp collisions at sqrt(s)=7 TeV are presented, based on 2.9 inverse picobarns of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give sigma(pp to WX) times B(W to muon or electron + neutrino) = 9.95 \pm 0.07(stat.) \pm 0.28(syst.) \pm 1.09(lumi.) nb and sigma(pp to ZX) times B(Z to oppositely charged muon or electron pairs) = 0.931 \pm 0.026(stat.) \pm 0.023(syst.) \pm 0.102(lumi.) nb. Theoretical predictions, calculated at the next-to-next-to-leading order in QCD using recent parton distribution functions, are in agreement with the measured cross sections. Ratios of cross sections, which incur an experimental systematic uncertainty of less than 4%, are also reported

Measurement of dijet angular distributions and search for quark compositeness in pp collisions at √s=7TeV

Dijet angular distributions are measured over a wide range of dijet invariant masses in pp collisions at root s = 7 TeV, at the CERN LHC. The event sample, recorded with the CMS detector, corresponds to an integrated luminosity of 36 pb(-1). The data are found to be in good agreement with the predictions of perturbative QCD, and yield no evidence of quark compositeness. With a modified frequentist approach, a lower limit on the contact interaction scale for left-handed quarks of Lambda(+) = 5.6 TeV (Lambda(-) = 6.7 TeV) for destructive (constructive) interference is obtained at the 95% confidence level

Optical solitary waves in a photonic band gap material

grantor: University of TorontoA detailed analysis of finite-energy solitary waves in two- and three-dimensional nonlinear photonic band gap (PBG) structures is presented. Solitary waves in a photonic crystal exhibiting a nonresonant Kerr response with a two-dimensional (2d) square and triangular symmetry group as well as a 3d fcc symmetry group, are described in terms of an effective nonlinear Dirac equation derived using the slowly varying envelope approximation for the electromagnetic field. Unlike the case of one dimension, the multiple symmetry points of the 2d and 3d Brillouin Zones give rise to two distinct classes of solitary wave solutions. Solutions associated with a higher-order symmetry point of the crystal exist for both positive and negative Kerr coefficient, whereas solutions associated with a two-fold symmetry point occur only for positive Kerr nonlinearity. We obtain approximate solutions using a variational method. The nonlinear wave equations are then solved numerically using the Ritz-Galerkin method. An analytical stability criterion is obtained for a spinor field satisfying a nonlinear Dirac type of equation. Our study suggests that, for an ideal Kerr medium, 2d solitary waves in a band gap are stable whereas 3d ones are stable only in a certain region of the band gap. We derive the properties of self-induced transparency (SIT) solitary waves in a one-dimensional periodic structure doped uniformly with two-level atoms. In our model, the electromagnetic field is treated classically and the dopant atoms are described quantum mechanically. Solitary wave formation involves the combined effects of group-velocity dispersion (GVD), nonresonant Kerr nonlinearity, and resonant interaction with dopant atoms. We find three distinct types of propagating solitary wave pulses. Far from Bragg resonance, we recapture the usual McCall-Hahn soliton with hyperbolic secant profile when the Kerr coefficient is set to zero. However, when the host Kerr coefficient is nonzero, the optical envelope function deviates from the hyperbolic secant profile and pulse propagation requires nontrivial phase modulation. When the laser frequency and atomic transition frequencies are near the photonic band edge, the additional effect of the GVD facilitates the propagation of a SIT-Gap soliton. The soliton structure changes dramatically as the laser frequency is tuned through the atomic resonance. A distinct type of near-band-edge solitary wave can propagate when the Kerr coefficient is zero. This third type of solution arises from the balance between GVD and the resonance interaction with the dopant atoms.Ph.D