You Might Hear A Cricket Chirp
Ormia ochracea is a tiny, parasitical fly and the bane of crickets. The fly listens for cricket chirps, homes in and deposits larvae on the back of the cricket’s back. The larvae then proceed to burrow into the cricket and eat it alive.
While this scenario is nothing for crickets to sing about, it’s absolute inspiration for researchers trying to develop the next generation of directional hearing aids, who describe a new, fly-inspired prototype in the journal Applied Physics Letters.
What’s particularly notable about the fly’s hearing abilities is that they derive from ears that are, well, extremely small. Human ability to detect the source and direction of sounds derives significantly from our large heads and widely separated ears. The latter receive the same sound at slightly different times. Our brains analyze that time difference and use it to locate the sound source.
The heads of flies, though, are just a millimeter or so wide, about the thickness of an average fingernail. (Incidentally, the fly above is resting on a fingernail so you can get a good sense of scale.) Flies overcome their size limitations by creatively tweaking the internal hearing structure. Between the two ears of a fly is a sort of see-saw that moves up and down, amplifying the incredibly small time differences of incoming sounds. It allows the fly to find chirping crickets quite well.
Researchers at the University of Texas have used the fly’s ear structure as a model to create minute pressure-sensitive devices out of silicon that they hope can eventually be used in new directional hearing aids that are smaller, more comfortable and longer-lasting.
21,000 years ago, the ice over Montreal was 3 kilometers thick, and dwarfed the Sears and CN Towers. The land is still rising back up like a sponge from the great weight of the ice. Conditions changing over time. (xkcd)
I made a chart of some bioluminescent species! Full image on tabletopwhale.com
Iridescent Hematite - Elba Island, Tuscany, Italy
Oh, what a treat! Alas, Elba hematite is almost exhausted, but this mineral, in this small island, has helped make great ancient Rome. They used to extract metallic iron from hematite, loading this mineral with coal in clay ovens that reached temperatures of 1300 °C. Blowing air inside the oven with a bellows, oxygen, carbon, and carbon dioxide produce carbon monoxide, which reacts with hematite to give metallic iron and again carbon dioxide.
Fe2O3 + 3CO —> 3CO2 + 2Fe
The metal was then worked extensively in the forge to get the final product.
(Source: fineart.ha.com, via libutron)
Dinosaur-killing asteroid hit at just the wrong time
Animals might have survived if impact happened a few million years earlier or later.
Just before a large asteroid slammed into the Earth 66 million years ago, the diversity of plant-eating dinosaur species declined slightly, a new study suggests. That minor shift may have been enough to doom all dinosaurs when the space rock hit.
The scarcity of plant-eaters would have left them more vulnerable to starvation and population collapse after the impact, with consequences that rippled all the way up the food chain.
“The asteroid hit at a particularly bad time,” says Stephen Brusatte, a palaeontologist at the University of Edinburgh, UK. “If it had hit a few million years earlier or later, dinosaurs probably would have been much better equipped to survive.”
Brusatte and his colleagues describe this nuanced view of the famous extinction in Biological Reviews.
Read more @Nature.