2D scaling approach for the first order transition in Bi_2Sr_2CaCu_2O_{8+y}

We analyze recent measurements by Ooi et al. of the angular dependence of the first order vortex phase transition in Bi_2Sr_2CaCu_2O_{8+y}. The experimental findings of these authors are interpreted in terms of a 2D versus 3D scaling approach. Invoking a crossover from a 3D to a 2D scaling approach, it shown, that the apparent failure of a 3D scaling approach away from the bulk transition temperature is due to a crossover to decoupled independent superconducting slabs.