I would say alive, but either very drugged or out and out terrified. Uncomfortable is an understatement to me. I fshe were deceased, I would expect more slackness in the jaw, unless it were wired, and I don't think Alcala had that skill (although if I'm wrong, please correct me.) It would also be difficult to pull off a standing posture with that rotation of the hips if she were deceased.
To aid in identification, I did notice that her right thumb is shorter and pudgier than her left, on reinspection, it may even be dislocated. I also might be crazy, but on the other arm, up against the glass, there appears to be a mark or line, possibly a ligature line about halfway between her elbow and wrist, on the inside of the arm. She also seems to have a very deep tan or sunburn across her shoulders, so the outfit fits the weather, as far as I can tell from the lack of goosebumps where her arm is contact with the window. The left side of her face appears bruised, under the eye and I think I see some bruising on that side of her nose as well. The bump on her nose indicates a badly healed break, as in it was never set and might have been recent (although I have seen some breaks that weren't attended to that still looked like that years later.) The dress, for being white, appears spotless, not something that she would have been wearing during a struggle or beating. The same with the hat, I seem to remember owning a couple hats like that, although smaller, and from what I remember, the straw snagged very easily, you couldn't really even walk under a tree while you had one on. I really think Alcala kept dress up clothes, since we are seeing to many repeated articles of clothing and things that don't really fit the wearer. I don't think she necessarily would have worn that in public, although it was different times, simply because she has no bra on and it's white...freak rainstorms and all. Do we know if he liked to dress up his subjects? Knowing how he liked to pose them, it wouldn't surprise me at all.
He certainly had an affinity for necklaces and things that went around the throat, didn't he?
The poor thing looks utterly terrified to me.