Per Lytsy and Ronnie Pingel (IMAGE) Uppsala University Caption Per Lytsy and Ronnie Pingel, authors. Credit Anna Edling Usage Restrictions Credit must be given to the creator. License CC BY 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.