Molecular and cellular aspects of re-entrant arrhythmias

In recent years it has become evident that myocardial tissue undergoes remodeling in diseased states such as myocardial infarction and hypertrophy which affects membrane channels, cell-to-cell coupling as well as the connective tissue matrix. Although the detailed mechanisms of ventricular arrhythmias in ventricular hypertrophy are not known, studies carried, out by computer simulations or high resolution mapping of electrical activity have suggested a complex interaction between changing ionic currents at the level of the cell membranes, altered cell-to-cell coupling and altered macroscopic structure. The present report summarises these recent developments and their potential relevance for arrhythmogenesi

Absence of lattice strain anomalies at the electronic topological transition in zinc at high pressure

High pressure structural distortions of the hexagonal close packed (hcp) element zinc have been a subject of controversy. Earlier experimental results and theory showed a large anomaly in lattice strain with compression in zinc at about 10 GPa which was explained theoretically by a change in Fermi surface topology. Later hydrostatic experiments showed no such anomaly, resulting in a discrepancy between theory and experiment. We have computed the compression and lattice strain of hcp zinc over a wide range of compressions using the linearized augmented plane wave (LAPW) method paying special attention to k-point convergence. We find that the behavior of the lattice strain is strongly dependent on k-point sampling, and with large k-point sets the previously computed anomaly in lattice parameters under compression disappears, in agreement with recent experiments.Comment: 9 pages, 6 figures, Phys. Rev. B (in press

The Dynamics of Sustained Reentry in a Loop Model with Discrete Gap Junction Resistance

Dynamics of reentry are studied in a one dimensional loop of model cardiac cells with discrete intercellular gap junction resistance ($R$). Each cell is represented by a continuous cable with ionic current given by a modified Beeler-Reuter formulation. For $R$ below a limiting value, propagation is found to change from period-1 to quasi-periodic ($QP$) at a critical loop length ($L_{crit}$) that decreases with $R$. Quasi-periodic reentry exists from $L_{crit}$ to a minimum length ($L_{min}$) that is also shortening with $R$. The decrease of $L_{crit}(R)$ is not a simple scaling, but the bifurcation can still be predicted from the slope of the restitution curve giving the duration of the action potential as a function of the diastolic interval. However, the shape of the restitution curve changes with $R$.Comment: 6 pages, 7 figure

The Majorana experiment: an ultra-low background search for neutrinoless double-beta decay

The observation of neutrinoless double-beta decay would resolve the Majorana nature of the neutrino and could provide information on the absolute scale of the neutrino mass. The initial phase of the Majorana experiment, known as the Demonstrator, will house 40 kg of Ge in an ultra-low background shielded environment at the 4850' level of the Sanford Underground Laboratory in Lead, SD. The objective of the Demonstrator is to determine whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a narrow region of interest around the 76Ge neutrinoless double-beta decay peak.Comment: Presentation for the Rutherford Centennial Conference on Nuclear Physic

Revisiting Late Globalization: A Commentary on Theorizing and Theoretical Deepening

In 2016, the article “Exploring Late Globalization: A Viewpoint” was published in Markets, Globalization & Development Review (MGDR). It concluded by pointing out that while there were views about the concept of ‘late globalization’ in multiple disciplines, the concept was evolving; and, therefore, theories about late globalization would also continue to evolve. This Dialogue essay, developed in close consultation with MGDR editors, is another step in such theoretical evolution

Inclusive study of bottomonium production in association with an η\eta meson in e+e−e^+e^- annihilations near Υ(5S)\Upsilon(5S)

We study bottomonium production in association with an $\eta$ meson in $e^+e^-$ annihilations near the $\Upsilon(5S)$, at a center of mass energy of $\sqrt{s}=10.866\,$GeV. The results are based on the $121.4\,$fb$^{-1}$ data sample collected by the Belle experiment at the asymmetric energy KEKB collider. Only the $\eta$ meson is reconstructed and the missing-mass spectrum of $\eta$ candidates is investigated. We observe the $e^+e^-\to\eta\Upsilon_J(1D)$ process and find evidence for the $e^+e^-\to\eta\Upsilon(2S)$ process, while no significant signals of $\Upsilon(1S)$, $h_b(1P)$, nor $h_b(2P)$ are found. Cross sections for the studied processes are reported.Comment: Submitted to EPJ-