Monthly Archives: May 2009

Grow Up

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25 And Over

Instructions upon reaching the age of 25.

Grow up.

And when I instruct you to grow up, I do not mean that you must read up on mortgage rates, put aside candy necklaces, or desist from substituting the word “poo” for crucial syllables of movie titles. Silliness is not only still permitted but actively encouraged. You must, however, stop viewing carelessness, tardiness, helplessness, or any other quality better suited to a child as either charming or somehow beyond your control. A certain grace period for the development of basic consideration and self-sufficiency is assumed, but once you have turned 25, the grace period is over, and starring in a film in your head in which you walk the earth alone is no longer considered a valid lifestyle choice, but rather grounds for exclusion from social occasions.

20 items.

4. Develop a physical awareness of your surroundings. As children, we live in our own heads, bonking into things, gnawing on twigs, emitting random squawks because we don’t know how to talk yet. Then, we enter nursery school. You, having graduated college or reached a similar age to that of the college graduate, need to learn to sense others and get out of their way. Walk single file. Don’t blather loudly in public spaces. Give up your seat to those with disabilities or who are struggling with small children. Take your headphones off while interacting with clerks and passersby. Do not walk along and then stop suddenly. It is not just you on the street; account for that fact.

I developed some of these earlier than 25, thanks to being in the navy (they frown on being late, for instance, though they’re not too keen on having you walk in heels). OTOH, being in grad school, and the corresponding lack of money, delayed a few others.

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CSI Utah

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Mysterious disappearance of explorer Everett Ruess solved after 75 years

The mysterious disappearance of Everett Ruess, a 20-year-old artist, writer and footloose explorer who wandered the Southwest in the early 1930s on a burro and who has become a folk hero to many, has been solved with the help of University of Colorado at Boulder researchers and the National Geographic Society. The short, compelling life of Ruess, who went missing in 1934 after leaving the town of Escalante, Utah, has been the subject of much speculation.

Not-so-Great Expectations

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Gendered expectations in teaching

[T]he expectations of how a male versus female instructor will behave are actually quite different. One of the papers I read discussed the fact that they interviewed students after they filled out evaluations (where a male versus a female teacher were rated and came out the same, quantitatively). It turns out that while the teachers were rated the same, the students have obvious differences in expectations. It came out that female instructors were available outside of class for more time than male instructors, but that they were still viewed as not being sufficiently accessible outside of class. In other words, students expected that female instructors should be willing to put in more time outside of class to help students in order to rate as well as male instructors who put in less time. If you think about the implications, it basically means that women will often have to do more work to get the same ratings.

The Color of Math

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sciencegeekgirl: Physics Toys Tuesday: Colored shadows

Color subtraction is what happens when you mix together pigments. Red pigment absorbs all light but red (which is reflected to your eye). Blue pigment absorbs all light but blue. So mix red and blue and you’ve subtracted all colors, getting black.

Light’s weird, though. You mix together all colors of light and you get white. The primary colors of light are red, green, and blue. You have receptors in your eyes for each of those colors. If your eye senses both red and green light at the same place, your brain says “cyan” (sort of blue-green).

Oh, Sure. Take All of the Fun Out of It.

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A Unified Quantum Theory of the Sexual Interaction

In the simplest theories of the sexual interaction, the eigenstates of the Hamiltonian describing all allowed forms of two-body coupling are identified with the conventional gender states, “Male” and “Female” denoted |M> and |F> in the Dirac bra-ket notation; note that the bra is superfluous in this context so, as usual, we dispense with it at the outset. Interactions between |M> and |F> states are assumed to be attractive while those between |M> and |M> or |F> and |F> are supposed either to be repulsive or, in some theories, entirely forbidden.

The treatment, however, is incomplete. There is no mention of the difficulty of describing an interaction in the dressed-state picture. Nor any analysis showing that M-F coupling with aligned spins may, with some probability, be equivalent to applying the creation operator (clearly, these are bosons), while in interactions with spins anti-aligned, this does not happen; both interactions usually occur with both particles in an excited state.

wavefunction

Evidence of Things Not Seen

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Until you do a CAT scan.

NYT: Autopsies of War Dead Reveal Ways to Save Others

Col. Howard T. Harcke, a 71-year-old Marine Corps radiologist who delayed retirement to read CT scans at Dover, noticed something peculiar in late 2005. The emergency treatment for a collapsed lung involves inserting a needle and tube into the chest cavity to relieve pressure and allow the lung to reinflate. But in one case, Colonel Harcke could see from a scan that the tube was too short to reach the chest cavity. Then he saw another case, and another, and half a dozen more.

In an interview, Colonel Harcke said it was impossible to tell whether anyone had died because the tubes were too short; all had other severe injuries. But a collapsed lung can be life-threatening, so proper treatment is essential.

Colonel Harcke pulled 100 scans from the archives and used them to calculate the average thickness of the chest wall in American troops; he found that the standard tubing, five centimeters long, was too short for 50 percent of the troops. If the tubing was lengthened to eight centimeters, it would be long enough for 99 percent.

“Soldiers are bigger and stronger now,” Colonel Harcke said.

The findings were presented to the Army Surgeon General, who in August 2006 ordered that the kits given to combat medics be changed to include only the longer tubing.

This reminds me of a story, possibly apocryphal, of a study done in WWII. The army wanted more armor on bombers to protect them, but needed to be selective about where it was placed, lest the speed and/or range suffer too much. And they didn’t really want to take planes in production to test them, since they were all needed in battle. So some people analyzed the damage pattern of planes that returned from missions. They assumed that anti-aircraft bursts were basically random, so the pattern of damage from returning aircraft indicated non-critical harm, and were areas that didn’t need reinforcing — it was the gaps in the pattern which indicated the fatal hits. and that was where additional armor would do the most good.

Who's That, Jack Spratt?

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In the recent foray into the physics of Goldilocks and the Three Bears, there was a comment on Chad’s post which mentioned Jasper Fforde’s The Fourth Bear. I had read the first book in the series, so I picked this one up a few weeks ago, and since this is the Jell-0 of reading material — always room for it — I finished it while atomic physics was still leaking out of my ears.

It’s good. Detective Inspector Jack Spratt is in charge of the Nursery Crimes Division, responsible for investigating any crimes involving anthropomorphized animals or persons of dubious reality from works of fiction, especially nursery rhymes. Vaguely reminiscent of Douglas Adams in terms of zanyness, but it all makes some weird sort of sense. As promised, the thermodynamics of the three bowls of porridge (a quasi-controlled substance, permissible only in rationed amounts) gives Jack a major clue to solve the intertwined mysteries in the book. There is another physics nit, though. It’s a spoiler, though, so stop reading if you plan on reading the book. Continued below the fold.
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