-- Women aren't so lucky when it comes to testosterone levels. In a meta-analysis of 43 different studies, two researchers from the Harvard School of Public Health found that women with higher than normal levels of the sex hormone had a greater risk of developing Type 2 diabetes, while men with high testosterone were at a lower-than-average risk. The study, published in the Mar. 15 issue of The Journal of the American Medical Assn., suggests that doctors might consider the differing risks of diabetes when prescribing hormone therapies for men and women. We are more evolved than our piscine ancestors, but fish can do something we can't: breathe underwater. Fish gills are a marvel of engineering. By pairing high surface area and precise control of water flow, gills enable fish to thrive on the small amounts of oxygen dissolved in water.
Now scientists are designing artificial gills to supply divers with a steady flow of oxygen from a wearable rig. The key, explains Harihara Baskaran, an engineer at Case Western Reserve University, is getting water to flow easily through microchannels, which mimic a real gill. Working with Infoscitex of Waltham, Mass., Baskaran is using chipmaking techniques to create tiny devices with hundreds of channels. Bump that up to 250,000 channels, and the device could generate enough oxygen for a person. The project is being backed by the military, which has visions of stealthy gill-equipped aqua-warriors. Those extra fries may not be the only thing making you fat. Two new studies have found genes that are closely linked to obesity and the way fat is distributed in the body.
In one large study, researchers at Boston University and Harvard School of Public Health screened more than 86,000 snippets of DNA collected from participants in Massachusetts' long-running Framingham Heart Study. One gene variant found in 10% of subjects was consistently linked to obesity. Studies of three other population groups confirmed the results.
Separately, scientists at the Joslin Diabetes Center in Boston screened DNA to find genes that determine whether fat is stored inside the abdomen, where it is most dangerous, or under the skin. Examining both mice and humans, they found three genes that correlated with a predisposition to accumulate belly fat.
Authors of both studies cautioned that the presence or absence of these genes is not destiny, since many overweight people lack these markers. So it's still best to skip the fries. Never forget a face? You are not alone. The ability to recall faces is so hardwired into our brains' visual processing areas that even infants can do it. This follows since, as a species, human survival has depended partly on the ability to recognize kin.
These days, remembering a password for a cash machine or a PC is nearly as important. Facial recognition can help there, too. Privately held Passfaces, in Annapolis, Md., has come up with a system that capitalizes on this human skill. From a library of thousands of faces, the system assigns you five head shots. You then go through a short training session, in which you practice picking each one out of a grid of nine other faces. From then on, you log in by clicking on your preassigned faces in a series of grids. ``Even after years, users can still recognize them,'' says CEO Paul Barrett.
The system is less prone to theft from keystroke-sniffing programs and other malware than regular passwords, says Barrett, and works even on cell-phone screens. With a few U.S. agencies now using Passfaces, Barrett is building larger face libraries to prepare for a global rollout.