Methods, systems, and apparatus for detecting andor validating a detection of a state change by matching the shape of one or more of an cardiac data series, a heart rate variability data series, or at least a portion of a heart beat complex, derived from cardiac data, to an appropriate template. A protective boot may be installed over the base of the support pipe assembly and bushing to provide a more pleasing appearance and to preclude entry of debris into the threaded connections. This allows the identification of \u201cexperts\u201d on \u201ctopics\u201d without any pre-defined categorization of topics or pre-computation of expertise. The machine also sends the read user identifier to a remote marketing computer. When the ink jet head is used in an ink jet printer using a water-base ink, the wettability of an ink flow passage within the head is good and, in addition, the good wettability can be stably maintained, permitting a high print quality to be ensured for a long period of time.