Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of radiation testing company Landauer (NYSE: LDR) radiated as much as 14% on eight times normal volume.

So what: I don't think I'm stepping too far out on the limb by saying the nuclear reactor disasters in Japan are driving volume and shares higher today. Investors are betting demand for the company's products will increase not only in Japan but also around the world as we re-examine the safety of nuclear reactors.

Now what: Since the stock has pulled back later in the day to a 5% gain, the value seems much more compelling. Sales of OSL dosimeters will likely increase in the near term, and it will be interesting to hear the company's comments about the disaster going forward. I am bullish after the pullback today and think increased demand will push shares higher.

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