Values of a non-polysomnographic physiological parameter set may be correlated to polysomnographically determined sleep states. Compositions of the invention should be useful as solvents and, perhaps, as catalysts for many reactions, including aromatic electrophilic substitution, nitration, acylation, esterification, etherification, oligomerization, transesterification, isomerization and hydration. The blocking circuit, such as a setreset latch in a preferred embodiment, generates a block signal to prevent write access to a nonvolatile memory device, such as flash memory, in response to signals provided to the enable and disable input terminals.