Hi all, I'm mailing both yt-users and yt-dev since I don't think there are many ramses users on yt-dev. I'd like some feedback from users of the RAMSES frontend about a pull request I just proposed: https://github.com/yt-project/yt/pull/1463 See the pull request for details, but briefly, I've made it possible to access the 'particle_age' field values for cosmology simulations as they are stored in the ramses outputs. Currently we apply an in-place conversion from conformal time to proper time when we read these data in, and it turns out this conversion makes it difficult to write a particle filter for DM particles that will work for all RAMSES data. The trouble is that if we change the meaning of the particle_age field, this may break the scripts of people who are currently using yt with RAMSES data. Then again, we already made such a change when we added the in-place conversion a year ago. If you have thoughts and opinions about this I'd very much appreciate to hear your comments on github. -Nathan