Wed links

Wednesday Links:

Cap'n Smith is talking about N. Iraq. I don't get out that way, so if you're interested, see what he has to say.

If you're interested in Western Iraq, Michael Totten is out there. Greyhawk and I put him on a bird just a few days ago. Nothing yet, but keep an eye on his site.

Slate magazine: helping you conceal murder since 2007.

Knox and Sollecito were on the right track: Bleach contains sodium hypochlorite, an extremely corrosive chemical that can break the hydrogen bonds between DNA base pairs and thus degrade or "denature" a DNA sample. In fact, bleach is so effective that crime labs use a 10 percent solution (one part commercial bleach to nine parts water) to clean workspaces so that old samples don't contaminate fresh evidence. Likewise, when examining ancient skeletal remains, researchers first douse the remains in diluted bleach to eliminate modern DNA from the surface of bones or teeth.

So, why did Knox and Sollecito's bleaching gambit fail? It's difficult to swab a knife thoroughly. Dried blood can stick to the nooks and crannies in a wood handle, to the serrated edge of a blade, or become lodged in the slit between the blade and the hilt. With help from a Q-tip, it's possible to eliminate most stains, but what's not visible to the naked eye might still be visible to a microscope, and sophisticated crime labs need only about 10 cells to build a DNA profile.

Bleach is perhaps the most effective DNA-remover (though evidently no methodology is failsafe), but it's not the only option. Deoxyribonuclease enzymes, available at biological supply houses, and certain harsh chemicals, like hydrochloric acid, also degrade DNA strands. It's even possible to wipe a knife clean of DNA-laden hair follicles, saliva, and white blood cells with generic soap and warm water. The drawback to this last method is that the tell-tale cells don't just disappear once off the knife. They linger on sponges, in drains, and even in sink traps, where wily investigators search for trace evidence.
I'll frame this with the China query of a few days ago. Free inquiry has its benefits and its hazards; you can be sure China wouldn't let a website post a get-out-of-jail-free kit like this one.

Today's debate topic: We are better off allowing the free distribution of information, including topics of this sort. Defend or refute, as you prefer. I'm a defender, by sentiment; but a proper debate club requires you to do both, regardless of sentiment.

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