Department of Computer Science, Institute of Molecular Systems Biology, ETH Zurich, Competence Center for Systems Physiology and Metabolic Diseases, Zurich, Switzerland. manfredc@inf.ethz.ch|Department of Computer Science, Institute of Molecular Systems Biology, ETH Zurich, Competence Center for Systems Physiology and Metabolic Diseases, Zurich, Switzerland. manfredc@inf.ethz.ch|Department of Computer Science, Institute of Molecular Systems Biology, ETH Zurich, Competence Center for Systems Physiology and Metabolic Diseases, Zurich, Switzerland. manfredc@inf.ethz.ch