Physics "News": Bio and Astro

I'm on vacation this week, and taking this opportunity to clear out a large backlog of news items that I flagged as interesting, but never got around to commenting on. I'll group them thematically, just to spread things out over a few days, and this post lumps together some results from biophysics and astrophysics that didn't make it into the previous posts:

• GZK cutoff confirmed: from Backreaction, a report on new observations of highly energetic cosmic rays. These are subatomic particles with energy roughly equaly to the kinetic energy of a tennis ball on a volley that hit the upper atmosphere from time to time, producing showers of other particles that are detected by observers on the ground. Nobody's quite sure where these things come from, but there's a theory that says there ought to be an upper limit on their energy, otherwise they'd start scattering off microwave background photons. There were some preliminary observations that seemed to detect particles above that energy, but new observations suggest that there really is a cutoff.
• "Tiny organisms move microstructures": Pretty much what it sounds like: a team at Drexel University figured out a way to tether bacteria to micron-scale pieces of epoxy, and make them drage the objects around. I'd like to think that there's some sort of nano-scale Yosemite Sam sitting on the epoxy yelling "Yah, mule!", but I suspect the reality is nowhere near that cool.

And that's about it for this week's "news." I should be back on Monday, tanned, rested, and ready for, um, whatever it is that I'll be doing Monday.