A power converter includes a current source providing an input current, a transformer having primary and secondary windings, a switch network coupling the current source and the primary winding, and a clamping circuit coupled to the switch network. The method and apparatus calculates the actual bit error rate for comparison with a target bit error rate. Another advantage of the present invention is the fact that it refers to live and active bacteria. The combined weights can include multiplying weights resulting from a permutation that was omitted during PFA processing by \u201ctwiddle\u201d factors generated during CTA processing. The pre-chirp is performed by red-chirp of which the value of the chirping parameter is positive. The compositions comprise one or more of a WT1 polynucleotide, a WT1 polypeptide, an antigen-presenting cell presenting a WT1 polypeptide, an antibody that specifically binds to a WT1 polypeptide; or a T cell that specifically reacts with a WT1 polypeptide.