Nuclear data, of a sort

Your exercise of the day is to show with trigonometry and geometry that lim(n*tan(pi/n), n→∞) = pi. (I got this while playing around at work with finding the equivalent area of a circle and a polygon with n sides.)

My landlady gave me, at my request, a bunch of pamphlets I discovered lying around. They're educational booklets published in the mid-'60s by the U.S. Atomic Energy Commision, printed right here in Oak Ridge. They're really cool -- they vary in subject matter from space nuclear power to physical attributes of plutonium to medical uses of radioisotopes. It provides a fascinating look into the past. For example, one of the medical uses was injecting [Na-24]Cl into a patient's bloodstream and placing shielded detectors at points in his body, using the intensity to calculate where flow constrictions might be. I really doubt they do that nowadays. (I assume it was superseded by MRI.)

I was curious to see if any of that detailed information on plutonium had been reclassified, so I did a little googling and came up with this interesting site. There is some really cool (and some useful) information there, but the organization that hosts it seems kind of questionable. Do they think that by posting a bunch of that kind of information, they'll make the US decide to release all of its nuclear secrets into the public domain and simultaneously cease development of advanced nuclear weapons? I hope not.

It works again!

Maybe six months ago, iTunes refused to sync photos to my iPod with an "error -50." Because I'd been having other problems with my iPod at the time, I gave up. But someone's hint gave me the solution.

Go to the terminal, type "xmllint ", and drag the file called "AlbumData.xml" inside your iPhoto library to the terminal window. Press enter, and it will hopefully spit out a few lines of text that say it had an error. It might be an album name or a comment in your photos (it was the latter in my case). Go to iPhoto, search for that comment, select all and delete in the comment box, and retype it. Quit iPhoto, and hopefully iTunes will start working again.