Figure 7.
Compressibility ratio, κb/κ0, versus block size, b. The compressibility, κb, is scaled with the compressibility of an ideal gas, κ0 = (ρkBT)−1, to obtain density-independent values. Shown are the data for fibroblast cells and HeLa strains I and II. To eliminate the influence of finite-sized effects, cells of the same shape have been simulated with a random distribution of localized fluorophores, yielding the expected value of κb/κ0 = 1. The nonconvergence of the compressibility indicates large-scale fluctuations of the histone distribution in the cell nucleus.