A method for forming an electropotential map, including: measuring locations of points on a surface of a body organ, and measuring electrical potentials of a subset of the points. A plurality of mounting bolts extending through the holes in the rotor shaft and holes in a mounting device of the shaft threadedly engage the clinch nuts of the clinch nut plate. Product, shopper, and other data related to the shopping experience may be collected and further utilized by the system provider. The second rod is longer than at least half a width of the display device. A preferred system of the invention comprises a validation authority, a logical boundary at which validation authority undertakes control of communications, and validation rules specifying parameters for observation and the nature of comparisons. More specifically, the invention relates to 1,6-naphthyridine derivatives and pharmaceutical compositions containing such derivatives.