Inconsistency of magnetic-moment conservation with entropy increase in collisionless shocks.

Collisionless shocks are multiscale objects. Energetic ion distributions are gyrotropic at sufficiently large distances upstream and downstream of the shock transition while at the transition itself the ion dynamics is significantly gyrophase dependent. Magnetic-moment conservation of an ion is widely used as a viable approximation during the shock crossing.

Direct evidence of nonstationary collisionless shocks in space plasmas.

Collisionless shocks are ubiquitous throughout the universe: around stars, supernova remnants, active galactic nuclei, binary systems, comets, and planets. Key information is carried by electromagnetic emissions from particles accelerated by high Mach number collisionless shocks. These shocks are intrinsically nonstationary, and the characteristic physical scales responsible for particle acceleration remain unknown.

Decorrelation of retinal response to natural scenes by fixational eye movements.

Under natural viewing conditions the input to the retina is a complex spatiotemporal signal that depends on both the scene and the way the observer moves. It is commonly assumed that the retina processes this input signal efficiently by taking into account the statistics of the natural world. It has recently been argued that incessant microscopic eye movements contribute to this process by decorrelating the input to the retina.

Turbulent viscosity variability in self-preserving far wake with zero net momentum.

The profile of the self-preserving far wake with zero net momentum depends on the effective turbulent viscosity coefficient. The current model is based on the assumption of uniform viscosity in the wake cross section. It predicts the self-similar shape of the wake where the width W depends on the distance z from the body as W∝z(1/5) for the axisymmetric case (or z(1/4) for the plane case).