Heat-seeking spermApparently, when it comes to finding a mate, sperm are not that far removed from their heat-seeking human hosts. Researchers at the University of Cambridge found that human sperm possess an infrared homing device which is key to their navigation through the female genital tract. The ovum is located at the end of the fallopian tube, which is on average, two degrees above body temperature. Sperm rely on this temperature differential to find their destination. Once they get closer, they home in on chemicals secreted by the egg to help them through the final stretch. Source: Nature Medicine—Mildred WongMicroscopic laser createdA laser beam one thousand times smaller than the width of a human hair has been created. Harvard researchers reported on Jan. 17 that wires made of cadmium sulfide just 100 nanometers wide emit laser light when a current is passed through them. The nanowire lasers are easy to make since no intricate cutting or assembling is required. A chemical reaction yields countless such wires in a single batch. These new lasers have many potential applications in telecommunications and electronics, and may one day be used in ultra-fast computers that would use light pulses rather than electrical signals to compute.Source: Nature—David ShigaNew oldest ancestor?The recent finding of a seven million year old hominid skull may shorten the evolutionary gap between humans and their ape ancestors. The skull was found in Chad’s Djurab Desert, and may well be the species from which humans and chimpanzees diverged. The examination of this particular hominid has pushed back the time at which hominids are thought to have first evolved. It has also shown that chimpanzees are not the last common ancestors of humans. But, as with all new finds in paleontology, more questions have been raised than answered, and research continues.Source: Scientific American—Wendy GuGeologists study site of Trojan WarGeologists working in Turkey have discovered that a giant bay surrounded the ancient city of Troy, which agrees with the account presented in Homer’s epic, The Iliad. Researchers believe Troy existed in what is now modern-day Turkey, which is covered by desert. Using carbon dating on fossils found near the ruins of Troy, scientists determined silt swept into the bay, gradually drying it up, slowly changing it into a swamp and finally into the present-day desert. The geologists also studied other aspects of the geography of the site and concluded the major geographical indicators presented in The Iliad are correct.Source: Nature —CDNose knows timeScientists have discovered that the “biological clocks” in fruit flies are tuned by their sense of smell in social environments. Exposing fruit flies to varying light conditions, researchers found that those in social group settings tended to synchronize their clocks with each other, whereas isolated flies have great difficulty adjusting to changing day-and-night cycles. Just exposing a fly to a chamber that had been previously occupied by a group of time-synchronized flies was enough to affect the fly to adjust its biological clock. Furthermore, this olfactory clock-setting feature was absent in flies deprived of the ability to smell.Source: Nature—Karyn LauFungus-farming with a twistA U of T botany prof has added a twist to the origins of fungus-farming ants. Leaf-cutter ants are the most famous fungus-farmers–they collect leaves for fungus to grow on, which they later eat. Evolutionary biologists are interested in this relationship, because it has lasted over 50 million years–long enough for it to shape the evolution of both parties in interesting ways. Now U of T’s Neil Strauss, along with other researchers has shown through DNA analysis that a third player has been involved in this relationship from the earliest times. The third player is a second kind of fungus–a parasite that destroys the edible fungus. The second fungus had been observed in association with the ants before, but it wasn’t realized until now that all three organisms have evolved together over millions of years.Source: Science—David Shiga
