Exercise apparatus including first and second foot pads coupled to a frame. 124, SEQ ID NO: 130, SEQ ID NO: 141 and SEQ ID NO: 142, the complementary sequences of sequences ; and the sequences equivalent to sequences and, in particular the sequence having for every series of 100 contiguous monomers, at least 50%, preferably 70% homology with sequences and respectively. The method further provides writing metadata for the virtual disk file in the unused portions of the virtual disk file. The check valve cartridge is capable of being assembled and tested for compliance with a predetermined relationship of flow versus pressure differential, prior to assembly into the plunger. The concealed security threat detection system generally includes a detection system comprising a detector array, an air-moving device, and one or more air-sampling devices. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.