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The Straight Dope

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If the average body temperature is 98.6 degrees F, why is it that when the air temperature reaches 85 or 90 we feel uncomfortable? --Scott Hadley, Santa Barbara, California

One of Cecil's competitors once wrote that it was because we wore clothes--as though all you had to do to be comfortable in 98-degree heat was walk around naked. Clearly what we have here is a failure to grasp the scientific essence of the thing, namely that the air temperature has to be lower than body temperature if you're to cool yourself efficiently.

Your body is a little fuel-burning engine, and like all engines generates waste heat. That heat has to go somewhere, lest you pop a gasket. The easiest place to put it is someplace cooler, such as the air around you. However, if the ambient air temperature is the same as your body temperature, you have to go to great lengths to shove the waste heat out into it, e.g. sweating like a pig or going out to K mart to buy an air conditioner.

What we want, therefore, is an ambient temperature that lets us dump waste heat with the least strain. From experience we know this temperature is 68 to 72 degrees F. If you're very lightly dressed you may prefer 80. But even if you're starkers there's no way you'll be happy when it's 98 in the shade.

I watch a lot of late night TV, and have noticed something strange. A number of stations sign off the air (announcing that they use five million watts, etc), but run a test pattern all night. Why do they do this? Doesn't all that electricity get a little expensive? --B.F., Chicago

It's not as expensive as what it might cost to fix things if they shut the transmitter off. UHF stations in particular use giant klystron tubes (maybe five feet tall and 200 to 300 pounds) that generate a tremendous amount of heat and often require water cooling. If you turned one off every night and turned it on again every morning the cool-down/warm-up cycle could eventually cause things to go out of kilter. I've heard of water leaks, for example, and you might just burn the sucker out.

To some extent concerns about cool-down/warm-up apply to all TV equipment, although a lot of it isn't as delicate as it used to be now that vacuum tubes have been largely replaced by solid-state. But there's always a certain amount of adjustment involved after a cold start-up, and the general feeling seems to be that if it's running all right now, let's just leave it that way. The reason you broadcast a picture rather than a blank carrier is that the call letters tell the world who you are. Of course, you could do like a lot of stations in larger markets--they sidestep the issue by broadcasting all night long.

THE LAST WORD ON CATS AND AIDS

This column has had further correspondence with David Kay of the Tree House Animal Foundation, who complained that Cecil erred when he said "people sometimes get [toxoplasmosis] when they eat undercooked meat or handle kittens" (May 22). We were talking about toxo because it's a disease that can be especially virulent when contracted by people with AIDS.

Having reviewed the medical literature, I'll concede there is no evidence that you can get toxo merely from handling kittens. On the other hand--and it seems to me this is the important point--cats are a significant carrier of toxo germs, which live in the cats' guts and are excreted with their feces. You can contract toxo if you come in contact with the feces, either by changing the litter box or working in the garden where the cat has buried its mess.

Cats infected with toxo only shed germs for a short time. Still, people at risk--and this includes pregnant women as well as AIDS patients--are advised to have someone else change the litter box, use disposable litter box liners, and keep the cat indoors to prevent it from contracting toxo if it isn't already infected. You should also wear gloves when working in soil and wash your hands thoroughly with soap afterward. Maybe your cat didn't bury anything there, but some other infected animal might have.

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.

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