Overlay Values Research Articles

A new storage reduction technique for the solution of the group problem

AbstractThis paper shows that by making use of an unusual property of the decision table associated with the dynamic programming solution to the goup problem, it is possible to dispense with table storage as such, and instead overlay values for both the objective and history functions. Furthermore, this storage reduction is accomplished with no loss in computational efficiency. An algorithm is presented which makes use of this technique and incorporates various additional efficiencies. The reduction in storage achieved for problems from the literature is shown.

A plaque assay system for rinderpest virus and its use in characterising virus adsorption

A continuous line of calf kidney cells was found suitable for the production of plaques by five strains of rinderpest virus known to differ in their virulence for cattle. No differences were seen in the morphology of the plaques produced by these strains. Plaques were first seen after 6 days incubation, and if neutral red was incorporated in the overlay appeared as “red” centres composed of a small cluster of cells taking up this stain more strongly than the healthy background cells; thereafter plaques enlarged very slowly and were only 1.5–2.0 mm in diameter after 14 days. Plaque counts did not increase beyond the 6th day of incubation and were unaffected by either agarose concentrations of 0.4 to 1.5% or overlay pH values between 6.7 and 7.85. It was shown that neutral red included in the initial overlay did not affect the sensitivity of virus titrations.