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Free convection flows which arise in a thermally stratified medium are of practical importance. Interest lies in the effect of stratification on temperature and velocity fields that arise in the flow and the consequent heat transfer from a heated body. In many engineering applications coneshaped bodies are often used. Free convection flow over a vertical cone has been studied by Hering and Crosh [I], Hering [2], Lin and Chao [3], Lin [4,] Alamgir [5] and recently by Watanabe [6]. A literature review reveals that the free convection flow over a vertical cone immersed in a stratified medium has not been studied so far. This has motivated us to carry out the present analysis. Laminar free convection flows over bodies of different shapes like vertical plate, sphere and cylinder in a stratified medium have been studied by various investigators; see, for example, Chen and Eichhorn [7-8].

Multiple forms of acetylcholinesterase from various strains of houseflies, Musca domestica (L.) were separated by polyacrylamide gel electrophoresis combined with specific substrate staining and gel scanning procedures. The head enzyme was studied most extensively and four isozymes were noted in fresh tissue. The isozymes differed in their kinetic properties: Michaelis constants (K m ) for acetylthiocholine varied over a 5-fold range and bimolecular rate constants (k i ) for various inhibitors varied over a 2-fold range. The isozymes also differed in the degree of inhibition by various organophosphates in vivo. Thoracic isozymes were found to be more sensitive to inhibition than head isozymes at the LD 50 dose of several organophosphates. The soluble isozyme mixture from a resistant strain of housefly exhibited a decrease in sensitivity towards all five organophosphates examined and this decrease in sensitivity was attributable to differences in their affinity for the enzyme, as measured by the dissociation constant K d . Evidence was provided that the isozymal variations were epigenetic rather than genetic.