Summing Logs of the Velocity in NRQCD and Top Threshold Physics
  To achieve reliable predictions of the top-antitop threshold cross section at a future e+e- Linear Collider logarithms of the top velocity need to be resummed. I review the issues that make this problem complicated and show how the task can be achieved by renormalization in an effective theory using the so called velocity renormalization group. The most recent NNLL order results are discussed. 
A. H. Hoang (Munich, Max Planck Inst.)