28 November 2006

Science Speculations

Safe Turkey Internal Temperatures

First, some too late breaking news on food safety, the U.S. Department of Agriculture has backed off of its traditional stance that turkey needs to have an internal temperature of 180 degrees to be safe to eat:

In its report to USDA, the expert panel noted, "This temperature [165°F] will destroy Salmonella, the most heat resistant pathogen of public health concern in raw poultry." However, at that point of doneness, turkey flesh may still be pink and its texture a bit rubbery, the report notes. On those grounds, it said, "higher final temperatures may be needed for consumer acceptability and palatability"—probably around 170°F for breast meat and 180°F for thigh meat.

This is encouraging, as I had personally long doubted that it really needed to be so hot to be safe.

Superconducting Computers In Space

Second, they've discovered a silicon based superconductor (it is doped with boron atoms). The downside, it only works at 0.35 degrees K. A subscription only Science News story reporting the advance notes that "making silicon so profoundly cold would be commercially impractical. . . ."

But, while it may be commercially impractical to cool silicon to 0.35 degrees Kelvin in a room that is 293 degrees Kelvin (about room temperature), it would be much more commercially practical if your device were located in deep space, where the temperature is about 3-4 degrees Kelvin, and it would, at least, be cheaper at locations like Earth orbit or the dark side of the moon, requiring you to cool your sample from not more than 80 degrees Kelvin.

Why not put a superconducting computer in space and then radio instructions to it, and have results radioed back? This wouldn't make sense for routine applications like word processing, where the second or so it would take light to get to the computer and back would be material, but might make lots of sense for processor intense applications like weather prediction models.

Margaret Mead Validated

Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it is the only thing that ever has.

-- Margaret Mead

A small committed thoughtful group that knows where they're doing can achieve change even in the animal kingdom. Here's an abstract of the article in Nature Physics (Hat Tip to Science News; citations omitted):

For animals that forage or travel in groups, making movement decisions often depends on social interactions among group members. However, in many cases, few individuals have pertinent information, such as knowledge about the location of a food source or of a migration route. Using a simple model we show how information can be transferred within groups both without signalling and when group members do not know which individuals, if any, have information. We reveal that the larger the group the smaller the proportion of informed individuals needed to guide the group, and that only a very small proportion of informed individuals is required to achieve great accuracy. We also demonstrate how groups can make consensus decisions, even though informed individuals do not know whether they are in a majority or minority, how the quality of their information compares with that of others, or even whether there are any other informed individuals.

Basically, the groups of animals wander randomly without information, influenced only by the location of their neighbors. These random impulses tend to cancel out. But, if someone with knowledge splits the difference between staying with the group and going where he knows the objective is, his purposeful movements will overwhelm the random ones.

Four or five ants that know where they are going is enough to lead a group of 30 to 200 ants, even without anyone knowing who actually knows where they are going, and without any communication other than an awareness of the location of each ant's immediate neighbors.

Is it such a stretch to suggest that similar mechanisms are at work in politics and markets? Asimov would be proud that we are finally starting to get a grip on these concepts.

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