There is now a large body of theory concerning algebraic varieties over finite fields, and many conjectures exist in this area that are of great interest to researchers in number theory and algebraic geometry. This 1995 book is concerned with the arithmetic of diagonal hypersurfaces over finite fields, with special focus on the Tate conjecture and the Lichtenbaum-Milne formula for the central value of the L-function. It combines theoretical and numerical work, and includes tables of Picard numbers. Although this book is aimed at experts, the authors have included some background material to help non-specialists gain access to the results.

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A simple and rapid bioautographic enzyme assay on TLC plates has been developed for the screening of acetylcholinesterase and butyrylcholinesterase inhibition by plant extracts. Enzyme activity was detected by the conversion of naphthyl acetate into naphthol and the formation of the corresponding purple-coloured diazonium dye with Fast Blue B salt. Inhibitors of cholinesterases produced white spots on the dye-coloured background of the TLC plates. The alkaloids galanthamine and physostigmine, which are known inhibitors of acetylcholinesterase, were used to determine the sensitivity of the assay. Various plant extracts were tested using the bioassay.

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