Magazine article American Scientist


Magazine article American Scientist


Article excerpt

Getting Personal

To the Editors:

I read with great interest "Uniquely Me!" by Brian Hayes (March-April, Computing Science) on uniquely identifiable personal information. Hayes's descriptions of the lengths to which companies go to capture these data and how incidental traits such as font choice can act as identifiers are fascinating. However, the article did not really differentiate between personal information that is fundamental and hard or impossible to change-such as one's birthday, skin color, and college attended-and other more incidental information, such as browsing history and email address. Perhaps one can imagine limits on data collection related to the former but not the latter.

Mark Gerstein

New Haven, CT

Global Changes

To the Editors:

In the Sightings column "Watching Earth Change" in the March-April issue, the two figures showing the change in global distribution of atmo- spheric carbon dioxide are confusing and misleading.

The legend points out that the scale for 2013 has been shifted by 20 parts per million. At first glance, this seems like a trivial adjustment. On closer examination, I discovered that because of this change the scales for 2003 and 2013 are totally different. There is no overlap.

The result is that the big increase in CO2 between the two years is obscured. Only by the closest examination can the actual difference be ascertained. Yes, as the legend says, "the rise in CO2 concentration is visible," but just barely.

These figures as presented are certainly misleading and miss the opportunity to display a dramatic effect.

John E. Douglas

Spokane, WA

Editor's Note:

It is correct that the rise in global atmospheric carbon dioxide is barely visible in the pair of maps on page 99 in the MarchApril Sightings column, but showing overall CO2 concentrations was not the point of the illustration. Scientists at the Jet Propulsion Laboratory, who created the images, intentionally altered the scale to highlight the specific locations where CO2 consistently collects in Earth's atmosphere. If they had not done so, the entire 2013 map would have been featureless red, with all locations at the top of the 2003 scale bar; the pattern of C02 distribution, which is useful for studying how the greenhouse gas gets distributed through the atmosphere, would not be visible. To alert readers, we noted the scale adjustment in our caption accompanying the image pair. …

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