A number of problems in physics can be reduced to the study of a measure-preserving mapping
of a plane onto itself. One example is a Hamiltonian system with two degrees of freedom…

Common variable immunodeficiency (CVID) is a primary immunodeficiency disease characterized
by markedly diminished serum immunoglobulins and impaired antibody responses (9…

A method for solving the initial-value problem of the Korteweg-deVries equation is
presented which is applicable to initial data that approach a constant sufficiently rapidly as| x|→∞. …

The problem of a one-dimensional stationary nonlinear electrostatic wave in a plasma free
from interparticle collisions is solved exactly by elementary means. It is demonstrated that, by …

Background The outcome of childhood asthma in adults has been described in high-risk
cohorts, but few population-based studies have reported the risk factors for persistence and …

A new type of axisymmetric magnetohydrodynamic equilibrium is presented. It is characterized
by a region of pressure and safety factor variation with a short scale length imposed as a …

Previous work by Johnson and Greene on resistive instabilities is extended to finite‐pressure
configurations. The Mercier criterion for the stability of the ideal magnetohydrodynamic …

This paper is concerned with the geometrical aspects of the reconnection of magnetic field
lines. Reconnection is associated with discontinuities in the overall field line organization of …

Background Breastfeeding is widely advocated to reduce risk of atopy and asthma, but the
evidence for such an effect is conflicting. We aimed to assess long-term outcomes of asthma …

The particle paths of the Arnold-Beltrami-Childress (ABC) flows \[ u = (A \sin z+ C \cos y, B \sin
x + A \cos z, C \sin y + B \cos x). \] are investigated both analytically and numerically. This …