Submerged granular flows through an orifice were investigated numerically in the context of sinkhole occurrences during a flood due to presence underground conduits. To account for fluid-solid interaction at pore-scale, we use numerical modelling that combines Discrete Element Method (DEM) solid particles with Lattice Boltzmann (LBM) fluid dynamics. The setup studied is submerged discharge from...

The quantum basin hopping algorithm for continuous global optimisation combines a local search with Grover’s algorithm, and can locate the global optimum using effort proportional to the square root of the number of basins. This article establishes that Jordan’s quantum gradient estimation method can be incorporated into the quantum basin hopper, providing an extra acceleration proportional to ...

An artificial burrow was developed which fits into standard laboratory cages and significantly reduces stereotypic digging in gerbils. Also, the causes of bar-chewing were assessed experimentally. Neither the lack of gnawing material, nor the spatial proximity of cage-lid bars and food in the hopper nor the routine husbandry procedure of transferring juvenile gerbils to a fresh cage, but premat...

earlier version of this paper was presented to " South African Economic Policy under Democracy: A Ten Year Review " held at Mostertsdrift in Stellenbosch, 28/10/2005. Useful comments received from Murray Leibbrandt and Geeta Kingdon are gratefully acknowledged and the usual disclaimers apply. The work reported here is an outcome of a collaborative project between researchers at the

Steganography is the science of hiding the very presence of a secret message within a public communication channel. In Crypto 2002, Hopper, Langford, and von Ahn proposed the first complexitytheoretic definition and constructions of stegosystems. They later pointed out and corrected a flaw in one of their basic constructions. The correction, unfortunately, introduced a need for expensive errorc...

In this paper I propose that the principles of Emergent Grammar (Hopper 1987, 1998) can be applied to lexical semantics. I discuss three instances of discourse semantics to show why an emergent view of semantics can provide a realistic account of semantics in discourse. The three cases are: 1) emergence and negotiation of meaning due to participant interaction in discourse; 2) (re)distribution ...