Quenching of spin operators in the calculation of radiative corrections for nuclear beta decay

Calculations of the axial-vector component to the radiative correction for superallowed Fermi $0^+ \rightarrow 0^+$ nuclear beta decay are here modified with quenched rather than free-nucleon coupling constants for the axial-vector and electromagnetic interactions with nucleons. The result increases the deduced value of $V_{ud}$ but does not restore unitarity in the CKM matrix.Comment: LaTeX, 7 pages, no figures, TASCC-P-94-1

Healthcare professionals should be mindful that victims and victim-bullies may have additional health needs associated with risk-taking behaviour

Commentary on: Kritsotakis G, Papanikolaou M, Androulakis E, et al. Associations of bullying and cyberbullying with substance use and sexual risk taking in young adults. J Nurs Scholarsh 2017;49:360–70. • The effects of bullying and cyberbullying can be linked to a number of health risk behaviours, education and healthcare professionals need to include prevention and intervention strategies within educational curricula, building on replacing maladaptive coping strategies with adaptive responses. • Future research should explore the adaptive and maladaptive coping mechanisms employed by victims and victim-bullies during the transition to adulthood and how this impacts on their relationships

Bicycle Urbanism, Blog 8

Student blog posts from the Great VCU Bike Race Book

Convective Ripening and Initiation of Rainfall

This paper discusses the evolution of the droplet size distribution for a liquid-in-gas aerosol contained in a Rayleigh-B\'enard cell. It introduces a non-collisional model for broadening the droplet size distribution, termed 'convective ripening'. The paper also considers the initiation of rainfall from ice-free cumulus clouds. It is argued that while collisional mechanisms cannot explain the production of rain from clouds with water droplet diameters of $20\ \mu {\rm m}$, the non-collisional convective ripening mechanism gives a much faster route to increasing the size of the small fraction of droplets that grow into raindrops.Comment: 6 pages, no figure

An exact effective Hamiltonian for a perturbed Landau level

Considers the effect of a scalar potential V (x, y) on a Landau level in two dimensions. An exact effective Hamiltonian is derived which describes the effect of the potential on a single Landau level, expressed as a power series in V/Ec, where Ec is the cyclotron energy. The effective Hamiltonian can be represented as a function H (x, p) in a one-dimensional phase space. The function H (x, p) resembles the potential V (x, y): when the area of a flux quantum is much smaller than the square of the characteristic length scale of V, then H approximately=V. Also H (x, p) retains the translational and rotational symmetries of V(x, y) exactly, but reflection symmetries are not retained beyond the lowest order of the perturbation expansion