A novel personal electronic device includes a first and second processors including associated operating systems and functions. Conductive cooling is realized by providing thermal coupling between each of two or more depression regions in the cover and one or more heat generating components. At least a portion of the flow path is a deformable tube. A common collector receives at least a portion of the sample fluid that flows through at least one of the first disk and the second disk. The edge score function is proportional to a between class variance for intensity values associated with the two selected channel segments.