Nottale's gravitational Planc constant ℏ_{gr}= GMm/v_{0} contains the velocity parameter v_{0} as the only parameter. In the perturbative expansion of the scattering amplitudes β_{0}=v_{0}/c appears in the role of fine structure constant.
There is however a problem.
 The model for the effects of ELF radiation on vertebrate brain inspired by a generalization of Nottale's hypothesis by replacing the total mass M in the case of Earth by M_{D}≈ 10^{4}M_{E} suggests that in this case the dark particles involved couple only to a part of mass identifiable as dark mass M_{D}.
 Since only GM appears in the basic formulas, the alternative option is that the value of G is reduced to G_{D}. This conforms with the fact that in the TGD framework CP_{2} length is the fundamental parameter G is a prediction of the theory and therefore can vary.
 A further option is that the parameter β_{0}=v_{0}/c≤ 1 is variable and equals to β_{0}=1 or to a value not much smaller than 1, say β_{0}=1/2.
These three options are critically discussed and compared. The cautious conclusion is that the the third option is the most plausible one.
See the chapter About the Nottale's formula for h_{gr} and the relation between Planck length and CP_{2} length or the article Three alternative generalizations of Nottale's hypothesis in TGD framework.
