Per Hammartröm, Linköping University (IMAGE) Linköping University Caption This is Per Hammarström, professor, Linköping University. Credit LiU Usage Restrictions Please use appropriate caption and credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.