Discovered: Stressed out men prefer bigger women; plumbing the brain's stem cells; the male sandpiper skips sleep in favor of sex; microbes could help sewage treatment power itself. 

Stressed out men prefer bigger women. If we're to believe the example set by Hollywood, fashion, and the media, it seems like all men lust after thin women. Not so, says research which indicates that attraction is subject to environmental situations. Scientists from various British universities conducted an experiment that placed research subjects in different settings, some inducing high stress, some calm and relaxed. Then they asked the male participants to rate the attractiveness of women that varied by body size. The stressed out men tended to choose heavier women, and the calm participants chose leaner ones. "Body size preferences are not innate, but are flexible," says Martin Tovée of Newcastle University. The findings agree with evidence from impoverished countries, where men typically prefer larger women. "Where resources are scarce, people prefer a heavy body in a potential partner," says Tovée. [Time]

Sewage treatment microbes make electricity. Imagine a sewage treatment facility that powered itself solely on the energy built by treating sewage—in other words, a perfectly self-contained system. Microbes that scientists have developed to purify human waste by consuming its organic matter may also be able to generate the electricity needed to power sewage treatment plants, electro-microbiologists have found. Researcher Bruce Logan of Pennsylvania State University says, "What we do is use certain micro-organisms which can be connected to devices to generate an electrical current that can be used to generate power." Currently, the U.S. diverts 3% of all generated electricity toward running waste water treatment plants, a reality that Logan says is not sustainable. [Reuters]

The sandpiper has no time for sleep—there's sex to be had. Rappers often boast that they can go "all night long," but how about going 19 days straight? It may sound exhausting. The male pectoral sandpiper can bypass sleep for over two weeks in its frantic pursuit of sex. Female sandpipers are only fertile for three weeks in the summer, and male sandpipers spend every waking hour trying to mate with them. Studying sandpiper mating habits, John Lesku from the Max Planck Institute for Ornithology found that the birds who slept the least conceived the most offspring. This study adds to the mystery of what sleep is actually for, reports Discover magazine's Ed Yong. "For an activity that we all do, we still don’t fully understand what sleep is for," Yong writes. [Discover]

Brain stem cells identified. Researchers are discovering more about stem cells, hoping that their findings will lead to treatments for autism and schizophrenia. These stem cells are responsible for the neurons that control high mental functions. The brain is structured in layers, with the innermost layers dealing with basic sensory and motor signals and neurons in outer layers handling more advanced tasks like self-awareness, language and problem-solving. Ulrich Mueller at The Scripps Research Institute in California found that neurons in the uppermost layer of the cerebral cortex were created by different stem cells than the innermost neurons. "A better understanding of the development of these layers and their functions may help us to understand the causes of these mental disorders, which could lead to better treatments in the future," says University College London's Andre Strydom. [New Scientist]