An active matrix display device includes a plurality of pixels arranged as rows and columns and column electrodes extending along corresponding columns of pixels. A change from a baseline mechanical activity is extracted from a signal of mechanical heart activity during pacing at each one of multiple pacing sites along a heart chamber. The light-receiving part is configured to receive incident light that is emitted by the light-emitting part and reflected at a detection site of a user. In an illustrated embodiment, welding apparatus is an ultrasonic welding unit, and apparatus is used to weld thermoset materials. Water can pass through gaps in the curbs, around ends of the curb and preferably flows through a connecting conduit that couples between the lanes at an end wall of a box-like enclosure subdivided by lanes in the pooling area. In some embodiments, the bladelets are foldable and one side of each bladelet is concave.