Tracking a Particle (image) Harvard University Caption The jerky movement of a particle within the cytoplasm does resemble thermal diffusion, 'but it's just not the case,' says Guo. Credit Image courtesy of Ming Guo, Harvard SEAS. Usage Restrictions Editorial use only. 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.