Disclosed is a signal splitting apparatus useable in a power amplifier having two or more power amplifiers. The signal generator generates reset signals to reset the processing module. A movable member is movably engaged with the casing and has two protrusions from an inside of the movable member. The vanes can be pivoted to adjust the effective cross-section area of the annular inlet. The compounds are generally aryl sulfonamide derivatives and are useful in pharmaceutical compositions, methods for the treatment of CCR9-mediated diseases, and as controls in assays for the identification of CCR9 antagonists.