Concordia diagrams are the most common way to present U-Pb data in the modern literature, so understanding them is key to understanding the method.

Since they've changed the standards again, our previous efforts now just amount to a fire drill.

Now, if you look at the chart of a stock that has suffered a collapse, you will see that at the bottom of each drop there is a small uptick, a rise in the price. This uptick, representing the smart money getting out because it knows what is coming, and fools getting in because they don't, is known as the dead cat bounce, so-called because if you drop a dead cat off a skyscraper the cat will bounce, too, but the movement doesn't mean the cat is alive.

Both herds and individuals distribute themselves over all of an area, and bison come back to regraze areas at varying time intervals.