The rare newfigator

The rare newfigator, originally uploaded by brunoj.

The rare newfigator, living primarily in the swamps of the Southeast, are known to be swift and crafty. They have also been known to f*ck your sh*t up!

RIP Vivitar Ultra Wide and Slim

My only film camera died today (when I got it out to take with me on an adventure out past the loop).

I’d like to get a hardier film camera with similar characteristics, especially the ultra wide angle lens. The Vivitar has a 22mm (plastic) lens which is really wide especially considering the 35mm file size (1.6x larger than the CCD in my DSLR for example). Any suggestions?

A numbered, centered text environment for LaTeX

While writing a paper I decided that I need a environment that resembles the usual equation environment, i.e. it takes some content, centers it on it’s own line in the page and then adds, flushed left, a reference number for later use. There might be some ready-made environment or package for doing this, but I couldn’t find one after googling for 20 minutes or so. So I decided to make one which was a nice exercise. I feel like I finally understand the point of the minipage and makebox commands. Here is some code for a new environment that I call numtxt.

\newcounter{txtctr}[section] \setcounter{txtctr}{0}
\newenvironment{numtxt}
	{% This is the begin code
	\refstepcounter{txtctr} \vspace{0.2cm} {\noindent
	(\arabic{section}.\arabic{subsection}.\arabic{txtctr})
	}\hspace{-36pt}\begin{minipage}[c]{\textwidth}\centering}
	{% This is the end code
	\end{minipage} \vspace{0.2cm}}

Basically, I setup a counter (called txtctr, the name stolen from some other bit of macro code), start the environment by displaying the reference number in the format: ( section . subsection . # ). Next we start a minipage which is as wide as the line and center our content inside the minipage. Then to get that minipage aligned right (i.e. to ignore the space taken up by the reference number) I move everything 36 pts to the left. 36 points is about how long the reference number is. There’s probably a better way to do this…

Chapter 2 problem 66 aka. dropping a marble into an egg cup

Imagine an egg cup and a marble you decide to drop into it. What’s the biggest marble you can drop into the cup and have it touch only at the very bottom? This is a classic problem in analytic geometry and calculus.

In the picture,
the egg cup looks like a parabola, let’s say its cross section is the graph of . The green marble touches the bottom, while the red one touches only on the sides of the cup.

Solution after the jump…

Knuth on permutation problems

Going to hear Knuth’s talk on permutation problems tonight, then to SF in SF at the Variety Preview room, part of the handsom Hobart building in downtown San Francisco.

On a different note, I can’t believe how bad wi-fi and cell speeds and coverage are in SF. Isn’t this supposed to be a high tech, highly connected city? Only if you can get a signal I guess.

National AMS Meeting

I’m in San Francisco at the 2010 Joint Math meeting. So far I’ve met Cliff Stoll and Don Knuth, two of my heros. Also, it seems everyone (well, not quite everyone) is tweeting the meeting using #jointmath and putting there @username’s on badges. I feel behind the times after having committed web 2.0 suicide by deleting my facebook and twitter accounts.

Oh well.

UGA Cop Training Day!

Recently, the cops on campus had a “campus shooter” training day in my building and in fact in my hallway and in fact they shot my door and left bullet shells under the door for me to find.

In the photo, the policeman holding the assault rifle is standing just outside my office door. Presumably his spent (paint-bullet) shells are those which rolled under my door. He must have taken serious fire though because my door and door frame were covered in paint-bullet paint and fake blood. I kid not.

More photos of the mock shootout here: Athens Online

Playing around in macro

Chainring tooth, originally uploaded by brunoj.

I picked up a 110mm macro lens for my canon 30d camera. It doesn’t have image stabilization which makes indoor shots like this one tough; needs lots of light. The plane of focus is amazingly narrow when the aperture is wide open. This was at f / 3.2 and the focus plane picks out a single tooth on my 34t chainring. Some other weird things happen when you open the shutter for a long time, for example:

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Jobs applied map

Here is a map, according to www.mathjobs.org, of the jobs I’ve applied to since Nov. 15, 2009. This is missing probably 20 or so jobs whose applications were paper or through a proprietary website.

There are too few jobs open in the western US. What’s the deal?

Trail run: City Creek Canyon, Salt Lake City UT

I’ve run this trail millions of times, the north side of City Creek Canyon, starting from The Avenues

From the (lower) aves, you descend into the “memory grove” area down a huge set of stairs, probably 200 ft so. The trail is paved through the lower part of memory grove / city creek park and you take take the South side of the river, or the North side. The South side is a paved pedestrian path. I usually choose the North side though which is a dirt trail close to the canyon wall. Near the end of the trail section there are several ways out, but in the snow its hard to find them.

I used to run up this canyon several times a week with my old roommate. We even ran a Thanksgiving race up the canyon and back one year, 2001 I think. He beat me by a long ways.