An optical modulator having an optical modulation part and a connection part for an optical fiber propagating light. This solid material can readily be stored in disposal sites because it is not water-soluble. The rules in the set of rules are associated with one or more operations that can be performed on content items in the electronic document. In still another embodiment, the line source is stationary and positioned parallel to the gantry axis and off center while the detectors move relative to the line source. The system configuration storage unit stores, in a correlated manner, each component of the data-processing system constituting each data transfer path and a program using each component as a data transfer path. A disclosed apparatus includes a seat mount having a locking arm pivotally mounted within the seat mount.