1. Vetsuisse Faculty, Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland.
2. Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.
3. Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Washington, Seattle, Washington.
4. Medical Service, Veterans Affairs Puget Sound Health Care System, Seattle, Washington.