Ruby but not Rails on my Resume [closed]

Question

I have listed Ruby as a skill on my resume becuase I've been programming in Ruby for 5 years while I work on my Ph.D. thesis. I've mostly been using it to implement natural language processing algorithms.

I'm starting to look for a job, and I posted my resume to a few sites (as an extra bonus when applying to certain on-target jobs). Now I get recruiters calling me to offer me Ruby on Rails jobs. The problem is that I've never learned Rails. It was never relevant to what I'm doing for my Ph.D.

How do you recommend handling this situation to avoid wasting my time and theirs? (And learning Rails probably isn't an option until I finish my thesis.) Can my resume be adjusted to make this clearer? Should it be adjusted? Should I just politely tell them on the phone that I don't know Rails?

By the way, the relevant part of my resume simply says:

Skills:

Programming Languages: C, C++, Java, Scala, Ruby, LaTeX

Databases: MySQL, XML, XPath

and lists a few other skill areas that couldn't possibly be confused with a Rails developer.