Reid asked whether all convex-cocompact subgroups of mapping class groups are separable. Using a construction Manning–Mj–Sageev, we give examples separable that free arbitrary finite rank, while prior seem to be virtually cyclic.

Abstract Using the Imperial College laboratory catchment facility data from 96 experiments on a slightly-roughened varnished strip catchment (1 m x 9.925 m) are used to investigate the performance of numerical models of overland flow based on the kinematic wave approximation. A simple four-parameter model incorporates the Darcy-Weisbach laminar flow and Manning turbulent flow friction relations...

The theory for non-stationary flow in translatory waves is developed for an inclined plane in a prismatic channel and a funneling channel. The existence of translatory waves traveling over dry land or superimposed on constant flow is established, and the dependance on the initial flow value is discussed. Inherent instabilities of the wave tail are discussed. Data from a CFD simulation of a joku...

Acid dissolution is a technique of removing a fossil from the surrounding rock matrix in which it is encased by dissolving that matrix with acid. Fossilized bone, though strong enough to be preserved for thousands or millions of years, is often more delicate than rock. Once a fossil is discovered, scientists must remove the fossil from its surroundings without damaging the fossil itself. Scient...

The persistence length of a single, intrinsically rigid polyelectrolyte chain, above the Manning condensation threshold is investigated theoretically in presence of added salt. Using a loop expansion method, the partition function is consistently calulated, taking into account corrections to mean-field theory. Within a mean-field approximation, the well-known results of Odijk, Skolnick and Fixm...