The adjustable traction table has a pair of patient supports, one of which is longer than the other. In addition, the image reading apparatus prevents position errors or misalignment at the start of the image reading, or at a restart of the image reading after the image reading is paused. The second basic formulation describes a polyol-based aqueous solution of polyvinyl alcohol with optional thickeners. The retarder lensing material is positioned adjacent to the polarizing lensing material such that each eye of a user sees an intended image, and an unintended image is blocked thereby when used in conjunction with suitably polarization encoded projected images. The feedback signal may be tied to the generation of the reset signal such that, during a locked state, the pulse width of the second control signal is approximately equal to the pulse width of the feedback signal, which helps reduce the sensitivity of the circuit to nonlinearities.