Science Sunday: Iapetus’ Mountains, Wolves v. Coyotes, Prostate Relief

Distant mountains

Himalayas of Iapetus
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The Cassini mission to Saturn has come within a thousand miles of the surface of the planet’s third largest moon, Iapetus, send back some spectacular pictures of the unusual body.

Iapetus is a sharply “two-toned” moon, with one side dark, the other light. The Cassini mission is showing a surface that is “heavily cratered, along with the mountain ridge that runs along the moon’s equator. Many of the close-up observations focused on studying the strange 20-kilometer (12 mile) high mountain ridge that gives the moon a walnut-shaped appearance.”

“Our flight over the surface of Iapetus was like a non-stop free fall, down the rabbit hole, directly into Wonderland! Very few places in our solar system are more bizarre than the patchwork of pitch dark and snowy bright we’ve seen on this moon,” said Carolyn Porco, Cassini imaging team leader at the Space Science Institute in Boulder.

Blow their house down

Wily coyote
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In 1872, Mark Twain wrote that the coyote “is a living, breathing allegory of Want. He is always hungry. He is always poor, out of luck and friendless. The meanest creatures despise him and even the fleas would desert him for a velocipede.”

Twain’s description has held up pretty well over the intervening century plus. It’s hard to find anybody who will defend poor Coyote. And now he’s getting picked on by the big, bad wolves. A study in the recent Journal of Animal Ecology found that the presence of wolves in coyote habitat reduces the coyote population density by more than 30 percent.

Studying wolf-coyote interactions in Wyoming’s Grand Teton National Park, Wildlife Conservation Society biologist Kim Murray Berger found that “wolves limit the range and numbers of coyote in places where the two species compete with one another.”

The coyotes can get a little of their own pack by living in packs, however.

“In terms of direct mortality, actual predation of wolves on coyotes was low, accounting for some 16 percent of the radio-collared animals. Also there was a clear indication that, with coyotes, there’s safety in numbers; transient coyotes without packs were more likely to fall prey to wolves, with 56 percent of transient coyote mortality being attributable to wolves. Also, transient coyotes in wolf-abundant sites were 117 percent more likely to leave an area frequented by wolves.

“A bigger threat to coyotes than wolves is humans, with 29 percent of the mortality in the study animals being human-related.

Prostate with relief

An increase in high-grade prostate cancers among men taking the drug finasteride is probably the result of better detection of cancer rather than cancers caused by the drug, according to a recent study.

Finasteride is a drug approved in 1992 to treat enlarged prostate in low doses, and prostate cancer in high doses. In addition to the findings about high-grade cancers, M. Scott Lucas of the University of Colorado Denver and Health Sciences Center and colleagues found that finasteride may inhibit the growth of low-grade cancers, which would contribute to increased findings of high-grade cancers.

In all, this would indicate that finasteride users are not at higher risk of developing high-grade prostate cancers. Lucas’ paper says:

Although induction of high-grade cancer cannot be excluded, the results suggest that high-grade cancer was detected earlier and was less extensive in the finasteride group than in the placebo group.

In an accompanying editorial in the Journal of the National Cancer Institute, Gerald Andriole, M.D., of Washington University School of Medicine in St. Louis, Mo., and colleagues wrote:

“Taken together, the studies…provide substantial reassurance that the increased proportion of high-grade cancer on biopsy in PCPT is not likely to be clinically relevant,” the editorialists write. Nevertheless it is necessary, they say, to continue research on the effects of finasteride and other similar drugs such as dutasteride on prostate cancer incidence.

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