Uncategorized
- Anthropology
Stone Age Role Revolution: Modern humans may have divided labor to conquer
A new analysis of Stone Age sites indicates that a division of labor first emerged in modern-human groups living in the African tropics around 40,000 years ago, providing our ancestors with a social advantage over Neandertals.
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19766
Regarding this article, economists would suggest that population growth allowed the division of labor. Notice that the most advanced economies are those with the largest populations, allowing for specialization in production. As Adam Smith wrote in 1776, “The division of labor is determined by the extent of the market.” Jim KleinSan Francisco, Calif.
- Tech
Crusty Old Computer: New imaging techniques reveal construction of ancient marvel
Scientists have figured out the arrangement and functions of nearly all the parts of a mysterious astronomical computer that was recovered from a 2,000-year-old shipwreck.
- Earth
Lead in the Water: Mapping gets a handle on disinfectant’s danger
Researchers are investigating the link between lead-contaminated water and chloramine, a chemical disinfectant that is increasingly used in municipal water supplies.
- Health & Medicine
A Toast to Healthy Hearts: Wine compounds benefit blood vessels
Researchers have identified a class of compounds in red wine that might be responsible for much of the beverage's cardiovascular benefit.
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19765
This article leaves us up in the air with this statement: “. . . since the traditional wine-making techniques still in use in southwestern France and Sardinia increase concentrations of polymeric procyanidins, he says, other vintners may soon adopt such methods.” As a home winemaker, I have to ask, Which techniques contribute to increasing procyanidins? […]
- Planetary Science
Howdy, Neighbors: Long-term study finds a batch of red dwarfs
Astronomers have found 20 previously unknown star systems that lie within 33 light-years of Earth.
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19764
This article says that a planet so close to a red dwarf would be forced to “rotate in sync” with the star. Is this the same situation that causes the moon to rotate in sync with Earth? Ken BollersHudson, Colo. Yes. First, the larger body (the red dwarf) pulls the smaller body (the planet) slightly […]
- Animals
New Butterfly: High-alpine species from low-life parents
Little bluish butterflies high in the Sierra Nevada could be one of the few animal species to have arisen from crossbreeding of two other species.
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19763
If membership in a species is characterized by the inability to breed with members of another species, how can there be “animal species known to have arisen from crossbreeding with other species? Jeffry D. MuellerEldersburg, Md. Exceptions happen. Also, biologists argue about what defines a species. —S. Milius I suggest that the new species be […]
- Health & Medicine
Cancer Link: Gene regulates progesterone effect on breast cells
The BRCA1 protein regulates the effect of pro-growth progesterone, which could explain why having a mutated BRCA1 gene predisposes a woman to breast cancer.
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19762
Your article made a common mistake in characterizing the mechanism of steroid-hormone receptors. These receptors are not “proteins on the cell surface” but rather, and uniquely, positioned intracellularly. Steroid hormones pass directly from the bloodstream to the cytoplasm, where they induce changes in the receptor proteins, enable movement into the nucleus, and activate specific genes. […]
