The present invention validates provenance dates of electronic documents. In the case of motion within a sub-picture, the block of coefficients is read in such an order that the obtained series of coefficients includes, as it were, two interleaved sub-series. In one embodiment, a patient assumes a position that causes back pain, and a substance such as an anesthetic or analgesic is introduced into the disc to determine whether the substance relieves the pain. The cathode heat exchanger is configured to exhaust a gas and the anode heat exchanger is configured to store and discharge a liquid.