Biasymptotic formula for the turbulent energy cascade

We present a family of differential models for the scaling exponents tau(p) which characterize the moments of the energy dissipation rate in turbulence. This scheme interpolates between the asymptotic values of the derivative tau'p of tau(p) versus p in the limits p-->+/-infinity and reproduces the negative-p part of the exponents spectrum tau(p) as well, in contrast with other recent conjectures. Each member of the family is defined by a sigmoidal function, the form of which remains open to theoretical investigations.