## Archive for **May 2009**

## Short Selling

If you want to understand the bare bones of “going short” in the stock market, read How Porsche hacked the financial system and made a killing by Ivan Krstić.

What is the morality behind going short versus going long?

Investing in shares, or “Going Long”, is a no brainer – its a force that allows **further wealth to be created**, rewarding those who see value early, and generally punishing those who forgo making rational judgements. Based on my simplistic understanding below, I’d say “Going Short” is likewise a powerful tool for * good *– a force that

**stops wealth from being destroyed**– by rewarding those who grab it before it burns up forever. Sure, there may be misuse, especially given the artificial layers of intrigue inherent in a mixed economy. But in

*principle*, shorting is quite heroic!

## The Basics of MRI

A great place to start learning about magnetic resonance imaging – Dr Hornak’s The Basics of MRI. There is a small test at the end of each chapter.

## Better Explained

For an intuititive understanding of basic mathematics, there are some brilliant articles by Kalid Azad at betterexplained.com/. Kalid writes to give the reader “Aha!” moments, and succeeds. For myself, just 3-4 hours on Kalid’s articles on the complex number* i* was more profitable than first year university maths – his “Aha!” moments have a way of sticking.

My favourite Kalid articles are:

- Complex numbers: visual introduction, intuitive arithmetic
- Geometry: Pythagorean uses, Pythagorean distance
- Calculus: a gentle introduction, discovering pi
- Exponents & Logs: Intuitive exponents, natural log

Benjamin Franklin would find essays by writers he liked, pull them apart and put them back together again. Richard Feynman did the same with radios. I’m doing the same with the articles above. Can you suggest some articles on maths as good as Kalid’s?