A line graph showing FSign2 as a function of Cai. The x-axis represents Cai ranging from 0.0 to 1.0. The y-axis represents FSign2 ranging from 0 to 12. The graph features a single red line that starts at the origin, rises sharply to a peak near 0.2, then decreases, reaching a minimum around 0.6, and finally rises again towards the end. All values are approximated.