A hearing application suite includes enhancement and training for listening and hearing of prerecorded speech, extemporaneous voice communication, and non-speech sound. The single muffler housing member at least partially defines an intermediate pressure discharge cavity and a discharge pressure discharge cavity. The method also includes identifying a region in a classification space in which the values for the populations are located. In another example, parameters derived from IEGM signals are used to limit the scope of an impedance-based optimization search to reduce the number of pacing tests needed during impedance-based optimization. A lubricant return channel having one inlet situated so as to be facing said lubricant deflector opens into the second volume of the second reservoir above the second reserve of liquid lubricant. The plate-shaped PROX reactor of the present invention includes a plate-shaped chamber having an inlet to supply gas and an outlet to discharge fluid, a distributor for distributing gas supplied into the inlet, a main reactor having a catalyst for converting carbon monoxide contained in the gas into another material, and a radiator disposed on an outer surface of the chamber to dissipate heat.