In California, hundreds of unionized graduate student workers at the University of California, Santa Barbara, walked out of classes and onto picket lines Thursday to demand a COLA — or cost-of-living adjustment. The grad students, who work as teachers’ assistants, say they’re severely burdened by high rents and low wages. Meanwhile, grad student workers at UC Davis say they’ll refuse to submit grades unless administrators agree to a monthly housing stipend to help offset skyrocketing rents in Davis.