Comparison of the scaling analysis of the mixed-state magnetization data with direct measurements of the upper critical field in Y-123

By comparison of recent direct measurements of the temperature dependence of the upper critical field $H_{c2}$ in an Y-123 high temperature superconductor with the scaling analysis of magnetization data, collected in fields H << H_c2, we demonstrate that that the temperature dependence of the Ginzburg-Landau parameter kappa is negligible. Another conclusion is that the normalized temperature dependence of H_c2 is independent of the orientation of the magnetic field in respect to crystallographic axes of the sample. We also discuss that isotropy of the temperature dependence of H_c2 straightforwardly follows from the Ginzburg-Landau theory if kappa does not depend on temperature.