The New Stone Age
Kidney stones will become more prevalent in the 21st century as the world warms up, according to Tom H. Brikowski of the University of Texas at Dallas and his colleagues. A crystallization of minerals dissolved in urine, a stone can form with the help of fluid loss. Such dehydration is more common in hotter conditions; the incidence in the southeastern U.S. is 50 percent greater than in the northwestern region of the country, for instance, and some U.S. soldiers shipped to desert conditions developed stones just 90 days after deployment. Factoring in the expected rise in mean temperature in the U.S.—upward of two to five degrees Celsius this century—the researchers figure that the nation will see 1.6 million to 2.2 million more kidney stone cases by 2050. This 7 to 10 percent increase could exact $1.3 billion in medical costs. The findings are crystallized in the July 15 Proceedings of the National Academy of Sciences USA. —Philip Yam
Who Will Die?
Researchers have built a computer system that can predict which death-row inmates are most likely to be executed. It consists of 18 computer processors that analyzed data on about 1,000 death-row prisoners, including their sex, age, race, schooling and whether they were ultimately executed or spared. Then the researchers fed it similar information about 300 more prisoners, leaving out whether they had lived or died. The system, using logic it had developed from the first set of data, correctly predicted the outcome for 92 percent of those cases. It found that death-row inmates with the highest chance of being executed are those with the lowest levels of education; neither the severity of the crime nor race could reliably predict a prisoner’s fate. The findings, which the researchers hope will lead to a fairer appeals process, appear in the Spring 2008 International Journal of Law and Information Technology. —Larry Greenemeier
Global warming is leaving trees behind. Some two thirds of forest species in six French mountain ranges have moved at least 18.5 meters higher on the mountainsides per decade during the 20th century. Previous research has demonstrated that plants at the highest elevations on mountains and in the polar regions have shifted to adjust to global warming. The latest result marks the first confirmation that entire ecosystems in lower, more temperate regions are moving as well. The study is in the June 27 Science. —David Biello
LOCATION INFLUENCES VOTERS
The voting location may tip the balance on some election issues. Researchers examined the 2000 Arizona general election that included a proposed tax increase to support school initiatives. After controlling for political preferences and zip codes, the researchers found that voters casting ballots at schools tended to support the measure (63.6 percent in favor) more so than those at nonschool booths (56.3 percent). A follow-up experiment revealed that voters could be subconsciously “primed” with images of lockers and classrooms to vote for a hypothetical tax for school spending. The July 1 Proceedings of the National Academy of Sciences USA contains the findings. —Philip Yam
Researchers have long suspected that a massive asteroid caused Mars’s “hemispheric dichotomy”: its crust thins from 50 to 20 kilometers over a south-north span covering 42 percent of its surface. Using gravity data and other measurements, scientists have discovered the hidden outline of the impact—in particular, an elliptical mark spanning 10,600 by 8,500 kilometers. Simulations suggest that the asteroid measured 1,600 to 2,700 kilometers wide, moved at about six to 10 kilometers per second, and struck at an angle of 30 to 60 degrees with the ground. —JR Minkel