This used to be the post entitled "Physics for understanding fMRI artifacts: Part Four." I had so many problems getting the draft published that I decided I wouldn't risk deleting this actual post, even though I have changed the title and the content. Wherever this thing points inside the "cloud" at Blogger, I want to seal it off like a leaky nuclear reactor and leave it for eternity, hopeful that it will be unable to infect any subsequent posts once it's buried in metaphorical concrete.
The replacement post, "Physics for understanding fMRI artifacts: Part F(f)our" is here.
I hadn't realized til recently just how flaky cloud computing can be. Clearly xkcd is way ahead of me, as usual: