AlanF said:
The article is about work from UCSD, the University of California San Diego, a part of the the Californian state university system.
Technically, UCSD is part of the University of California (UC) system; the California State University (CSU) system is a separate system although both are public university systems supported by the State of California. Generally speaking, the UC's are the highest tier of the public university in the state, with the CSU's being the next tier down. When you see a city name after the UC designation (e.g. UCSD) it's referring to that campus, while "the University of California" refers to UC Berkeley (aka Cal), which was the first campus in the system (and the genesis of others - their medical school became UC San Francisco, their university farm became UC Davis).
Probably TMI, but then, I went to UC Berkeley (and as we said at UCLA games, "There's only one Cal, and it's in Berkeley. Get your own colors, get your own fight song, get a real bear!").