Albert Snowball; Bryon Skinner/CDC; Aditya Joshi

Top Stories: A Shocking Way to Improve Math Skills, Kepler Malfunctions, and More

Trouble With Math? Maybe You Should Get Your Brain Zapped

Do you pull out your iPhone to calculate the tip at the end of every meal? You're not alone—20% of adults struggle with basic math. A quick zap to the brain might be the answer. A study shows that applying gentle electric stimulation to the brain can boost math skills for up to 6 months. But don't go strapping a battery to your head just yet—researchers don't fully understand how it works, and there could be side effects.

Diarrhea Deaths Decoded

Researchers have isolated the four microbes responsible for causing diarrhea, which kills 800,000 kids in the developing world each year. The biggest surprise was the discovery of a parasite called Cryptosporidium as one of the culprits. Compared with the other three microbes, Cryptosporidium is understudied, and scientists are hoping to speed up research into how to protect against it. In the meantime, a vaccine against one of the other major diarrhea-causing microbes, rotavirus, is ready for rollout in India, where scientists are hopeful that it will help save lives.

Rising Numbers May Not Be Enough to Save Tigers and Kiwis

When it comes to threatened animals, increasing their numbers seems like a happy ending. Not quite, researchers say. A population increase is all very well, but if animal populations experience a loss of genetic diversity, they might be doomed anyway. A lack of genetic diversity can leave a species vulnerable to diseases or threats like a change in climate, because they don't have the evolutionary resources that they need to cope. Researchers are calling this discovery a conservation "red flag" and have identified two species clearly at risk from genetic isolation: the Bengal tiger and the little spotted kiwi.

Malfunction Could Mark the End of NASA's Kepler Mission

After 4 years of faithful service, a reaction wheel malfunction may have scuppered the planet-hunting Kepler spacecraft for good. Kepler is one of NASA's most successful missions—it has discovered more than 2700 possible planets and completed its original 3.5-year mission and then some. But this malfunction has left the craft unable to point in a specific direction, a pretty important skill for a planet-hunter. NASA engineers have put the craft in safe mode and are looking for solutions, but it looks like it may soon be lights out for Kepler.

U.S. Supreme Court Upholds Monsanto Soybean Patents, Rejects Blame-the-Bean Defense

Agribusiness giant Monsanto has won a long-running case against an Indiana farmer who refused to pay royalties on unlabeled beans that he'd bought containing Monsanto-patented genes. The U.S. Supreme Court unanimously ruled that the company's patents cover not just genetically engineered seeds distributed by Monsanto itself, but also any seeds in the environment that contain Monsanto's genes.