Disclosed is an electro-absorption optical modulator using a semiconductor device. In particular, Aap and the five gene cluster of the AA probe region of the pAA plasmid of EAEC 042 have been identified, sequenced, and further characterized. The corresponding apparatus has a callback device which is driven when a given time period is exceeded or when the message has been retrieved. A plane containing the gaze vector is defined by rotating a base plane through the angle in a camera image plane between a pupil center, a first glint, and a second glint. The valved catheter includes a catheter tube having a necked portion in its proximal end that forms an integral valve, the necked portion being surrounded by a compression sleeve that biases the valve in a closed position. When updating meta data stored in an HDD, log data for reconstructing the meta data after update from the meta data before update is written into a non-volatile RAM, then, after this writing is completed, the update is executed.