Per Aspenberg, Linköping University (IMAGE) Linköping University Caption Per Aspenberg, Professor emeritus at Linköping University, Sweden Credit Thor Balkhed/LiU Usage Restrictions Please use an appropriate caption and photo 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.