Defining noir (in Providence)

Those who know Ann Hood know she's had some really difficult passages in her life and that she writes beautifully about personal tragedy and the her writing helps her heal and helps her readers as well - building in us empathy, compassion, and understanding. I was surprised to see these elements, however, in Hood's story selection for the Providence Noir (Akashic) anthology she's edited, but there they are in his story Beneath the Shepard Clock. I won't give anything away about this elegantly plotted story that turns on a dime toward the end. Noticing, as I read through the noir anthology, that teach of the 1st 4 stories involves a violent death or an assassination; is that de rigeur for a noir story, or just a predilection of the Hood's or just a coincidence in this anthology? It seems to me that not all noir fiction has to be about violent death, and I'm interested to see how (and if) the later stories in the anthology establish a noir attitude. I'll note also for the record that Leuci's story in the anthology has Providence tough-guy lingo down the best, so far.