In an optical recording medium comprising a substrate including parallel extending lands and grooves on one surface thereof, the grooves serving as recording tracks, and the lands being formed with prepits, the height HP of the land disposed between the prepit and the groove divided by the height HL of the land in a prepit-free region, both as measured from the groove bottom, i. One implementation involves a method of detecting a digital watermark. In some implementations, a voltage to current converter circuit generates the bias current from a constant reference voltage that is independent of temperature and voltage supply variations. When provided with temperature and humidity sensors coupled to the processor, the processor may calculate a comfort index and adjust the pre-determined path or air flow velocity accordingly. Continuously varying the angle of both the backrest and seatbed portions of the seatingfurniture or accessories relative to the ground may improve a user’s seating comfort, for example, by decreasing or negating the user’s need to shift position on the seat when reclined or continuously responding the user’s shift in position. A step of obtaining an image that reflects the chromosomal state in the cell, and a step of calculating a parameter that corresponds to the chromosomal state based on the image to determine the stage in the cell cycle on the basis of the calculation result are included.