If that's a challenge, good luck getting a lot of NotProgrammers to move to a completely different language.
Besides, if I may be blunt, who in Rubyland cares if these guys are on Python? By and large, these people are on an island. They are optimizing for things you pretty much don't care about, for programming styles you're not using, for libraries you've barely heard of. Trying to entice them off of Python onto Ruby is a waste of time for everybody. The Ruby community would at best get nothing, at worst net pain of supporting a lot of newbies, and the scientists would incur the horrifying overhead of a language shift for the closest thing to a sidegrade available in the set of the top 20-ish language. If they were going to do that they probably shouldn't be going for Ruby, they should probably be going for Haskell or OCaml, both languages for which I could outline actual advantages to the scientists for the pain of the switch (though probably not enough to justify the switch).
Ruby performance in general is getting much better and when C extensions are necessary (as they often are in any high level language) libraries like ruby-ffi have taken a lot of the pain out of that process.