Processes are disclosed for preparing piperidine derivative compounds of the formulae I, II or III:. Walkers of the present invention have crossbars at a front thereof constructed of telescoping tubing and lockingunlocking mechanisms. The computer readable medium may store program instructions for a syndication manager component communicatively coupled to a content producing component arranged to be executed by the processor. The manifold base portion and the manifold cover portion may be selected from a group of differing parts to provide a manifold having desired application or performance characteristics. The feature is calculated using the historical information based on the user or group of users activities. The interchangeable fan blade system is a set of support arms attached to the rotating portion of the fan and having one of a variety of connectors for removably attaching one end of the fan blades to the support arm.