Contrast and Bias Share Fraction - Biophysical Chemotaxis and Gradient Sensing Step by Step

The occupancy contrast must be the same fraction used by the run-bias check. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Occupancy contrast is one fourth

High occupancy minus low occupancy gives 1/4.

\frac{3}{4} - \frac{1}{2}=\frac{1}{4}

The run ledger uses that same fraction

The run-bias fraction is also 1/4, so contrast and motion are tied by source refs.

\frac{1}{4}=\frac{1}{4}