Here's some explanation of where this comes from, and why it's not considered in radiation safety:
http://scienceblogs.com/pharyngula/2011/03/will_radiation_hormesis_protec.php
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Radiation is always harmful — it breaks DNA, for instance, and can produce free radicals that damage cells. You want to minimize exposure as much as possible, all right? However, your cells also have repair and protective mechanisms that they can switch on or up-regulate and produce a positive effect. So: radiation is bad for you, cellular defense mechanisms are good for you.
Hormesis refers to a biphasic dose response curve. That is, when exposed to a toxic agent at very low doses, you may observe an initial reduction in deleterious effects; as the dose is increased, you begin to see a dose-dependent increase in the effects. The most likely mechanism is an upregulation of cellular defenses that overcompensates for the damage the agent is doing. This is real (I told you there's a grain of truth to what she wrote), and it's been observed in multiple situations. I can even give an example from my own work.
Alcohol is a teratogenic substance — it causes severe deformities in zebrafish embryos at high doses and prolonged exposure, on the order of several percent for several hours. I've done concentration series, where we give sets of embryos exposures at increasing concentrations, and we get a nice linear curve out of it: more alcohol leads to increasing frequency and severity of midline and branchial arch defects. With one exception: at low concentrations of about 0.5% alcohol, the treated embryos actually have reduced mortality rates relative to the controls, and no developmental anomalies.
If Ann Coulter got her hands on that work, she'd probably be arguing that pregnant women ought to run out and party all night.
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I might note that Lawrence Solomon is known as a climate denialist, and his book The Deniers apparently has a mix of scientists who complain that their views are represented, and cranks.
-- Andy