A classifying seat occupancy detection device is used to classify whether a particular seat is occupied by an adult, an infant or not at all. In the process, the natural gas stream to be liquefied is partially cooled, expanded to an intermediate pressure, and supplied to a distillation column. The light fixture may be fashioned such that it closely mimics existing, commonly available recessed ceiling lighting assemblies. The key server transmits the decryption key to the mobile device after authenticating the user of the mobile device. A pressure seal is formed between the pack off rubber and the wireline when the pack off rubber is sufficiently compressed by the piston. More specifically, the invention provides compounds useful as \u03bc opioid receptor ligands.