Wednesday, May 26, 2010

Integral of four Hermite polynomials

Anyone know anything similar to Saalschutz's theorem?

I was trying to simplify the integral of four Hermite polynomials, and I can't get rid of the last summation.

Wednesday, May 12, 2010

Hey, everyone else was doing it

A malamanteau is a word which is both a portmanteau and a malapropism. This means that the word must
  • (portmanteau) be a combination of two (or more) other words (and their meanings), and
  • (malapropism) have been used because it sounds correct in that place in the sentence, but is actually either nonsensical or an unusual word.
"Malamanteau" also implies that the speaker or writer has used language in an unusual way.

The word was first published on the Internet here. The examples by which the word was defined are
During the first discussion, the guy described his misunderstanding of what someone was saying by stating, "I misconscrewed it up."

The second time, another guy explained his inability to talk while upset by saying he was, "flustrated."
In a curious twist, "malamanteau" is a portmanteau of "malapropism" and "portmanteau".

As a result of a recent xkcd comic, "malamanteau" is now also a neologism ("a newly coined word that may be in the process of entering common use, but has not yet been accepted into mainstream language").

Tuesday, May 11, 2010

1000 tonnes of CO₂ = 1 person's house.

So, here's a (ridiculously rough) calculation.

An increase of 200ppm (doubling) the CO₂ concentration in the atmosphere warms the globe considerably. Antarctica and Greenland melt, raising the sea level by 80m. Perhaps 1/6 of the world's population is displaced -- say 10⁹ people have their houses washed away. People tend to live near the coast, after all.

There are about 10⁴⁴ molecules in the atmosphere, so 200ppm is something like 2×10⁴⁰ molecules. This many molecules of CO₂ weighs about 10¹² tonnes.

So, for every thousand tonnes of CO₂ added to the atmosphere, one person's house gets washed away.

By way of comparison, the dirtiest power station in the world, Hazelwood, in Victoria, Australia, puts out 17 million tonnes of CO₂ every year. That's 17,000 people's homes worth.

I think it's time the world switched to nuclear power. If France can do it, surely the rest of us can? Some kind of thorium reactor would probably be the best option. Alternatively, a biological answer is also possible... but that would use a large fraction of the earth's surface given photosynthetic efficiency of about 1%.

Yep, no references. If we don't agree, do the calculation yourself with your own sources. Arguments about linearity etc. are probably valid too, but we have to admit that this gives us a rough idea.