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Computer Models Show Terror Birds Hunted by Sound

Terror birds, one of South America's most feared prehistoric predators, didn't use super sharp eyesight to catch prey, as do eagles, hawks, and other modern day raptors. Using sophisticated computed tomography X-ray scans and 3-D modelling software, researchers were able to show that these flightless giants actually hunted by listening to their quarry’s footsteps.

Terror birds, or phorusrhacids, to give them their scientific name, were top predators in South America for fifty million years after the dinosaurs died out, finally going extinct 1.8 million years ago. Terror bird fossils have also been discovered in North America, Africa, and Europe. These feathered killers stood from1 to 3 meters tall. They had huge hooked beaks, and the biggest ones could use them to kill with one gigantic stab.

In 2010, paleontologists discovered the almost complete skeleton of a new species of terror bird, near Mar del Plata in Argentina. They named it Llallawavis scagliai, after Galileo Juan Scaglia, one of Argentina's most celebrated naturalists. Scaglia’s grandson, Fernando, was part of the discovery team.

Subsequent analysis revealed that this bird would have stood 1.2 metres high and weighed around 18 kilograms. The remains were so well preserved, however, that a team led by Federico Degrange, assistant researcher of vertebrate paleontology at the Universidad Nacional de Córdoba, was also able to study the bird’s auditory system.

Degrange used a hi-speed medical CT scanner to produce detailed 2-D images of the bird’s inner ear. CT scans enable scientists to see minute detail inside fossils. These images were then transformed into 3-D segmented models using Materialise Mimics, 3-D imaging software. Mimics (Materialise Interactive Medical Image Control System) uses a special medical imaging aglorithm called “marching cube”  that takes partial volume into account to produce more accurate 3-D models.

The results were published in the Journal of Vertebrate Paleontology. Degrange explains that he based his deductions about Llallawavis’ hearing capabilities on the length of the terror bird’s cochlea.

“We calculated that it would have had a mean hearing range of approximately 3800 Hz and a mean hearing sensitivity of approximately 2300 Hz,” he says. Mean hearing range is the average difference between the highest and lowest frequencies that the bird could have heard. Hearing sensitivity, is the frequency at which the bird's hearing was the most acute.

Llallawavis would have been much better at hearing low frequency sounds than are humans. We hear best between 4,000 and 5,000 Hz. The ability to hear low frequencies would have also helped it locate and track the small mammals and birds it preyed upon. The bird would have been able to hear footsteps, even if the prey animal was hidden in the undergrowth. Crocodiles hear low frequency sounds. So too, did Tyrannosaurus Rex.

Degrange also thinks that Llallawavis would have had a deep booming voice, a bit like an ostrich. “This is plausible to hypothesize because the vocalization range of most birds falls within the lower half of their hearing sensitivity range,” he says.

Degrange admits that he doesn’t know about the bird’s voice for sure, though. The tracheobronchial syrinx, the structure that produces sound in birds, was missing from the remains. This structure is made mainly of cartilage and didn’t survive 2.5 million years in the ground.

Degrange is currently studying the terror bird’s eye bones, brain case, and skull. He intends to discover more about its vision and senses, and from this deduce whether Llallawavis was active during the day, at night or during twilight hours. This he hopes, could provide clues as to why terror birds died out.

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United Launch Alliance, a joint venture between Lockheed Martin and Boeing best known for their Delta and Atlas rockets, has just announced a next-generation rocket called Vulcan. Using Blue Origin's forthcoming BE-4 engines, and with a not entirely crazy airfoil and helicopter mid-air retrieval system, Vulcan is ULA's attempt field a commercial launch system that can compete with SpaceX on both capability and cost.

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This week at the IEEE Neural Engineering conference, however, the distinguished neurosurgeon Hugues Duffau argued that information that surgeons gain on the operating table should guide the development of brain-computer interfaces (BCIs). “My conclusion is that neurosurgeons are underused,” said Duffau, chair of neurosurgery at Monpellier University in France. 

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Launched 25 years ago today, the Hubble Space Telescope (HST), or simply “the Hubble,”  became the world’s eye on the universe, delivering to astronomers and the general public an endless stream of images with unsurpassed clarity.

Many revolutions in astronomy have been tied to specific telescopes and their uers, from the tiny telescope with which Galileo proved that the Earth revolved around the Sun and discovered the moons of Jupiter, the Leviathan of Parsonstown, used to by the 3rd Earl of Rosse to discover the spiral structure of what are now known as galaxies, and the 2.5-meter Hooker Telescope used by Edwin Hubble during the 1920s to measure the expansion of the Universe itself. And over the last quarter century, the HST has kept up this noble tradition. 

Although the Hubble’s mirror, with a diameter of 2.4 meters, is smaller than the mirror of even the Hooker telescope, it’s location in orbit above the Earth’s distorting atmosphere and the use of state-of-the-art CCD image sensors has helped to pin down the age of the Universe, determine the existence and distribution of dark matter and dark energy, and probe the atmosphere of planets in distant star systems. 

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The easiest (and probably best) way to deal with the space junk problem is to stop producing space junk in the first place. We’re trying to do that, which is great. But even if space agencies and commercial launch companies all commit, tomorrow, to rockets and satellites that will deorbit themselves after no more than 25 years, there’s still all kinds of debris flying around up there, threatening our orbital infrastructure.

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To measure the previously unmeasureable, data from TrackMan radar units are combined with stereoscopic images from two camera arrays, spaced 15 m apart. The radar measurements are useful for keeping track of the ball dynamics (including its spin), while video is useful for tracking player movements. Unlike the SportVU player tracking system used in the NBA, which has a top-down view on the action, Statcast’s camera location requires it to intelligently resolve player occlusions. 

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MIT Turns Thumbnail into Trackpad

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Laser-printed polysilicon transistors on paper

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The ability to print silicon onto substrates has existed for some time, but producing solid silicon from liquid polysilane ink required exposing the silicon to temperatures upwards of 350 degrees Celsius—far too hot for many of the flexible surfaces onto which one might want to print. The new technique, from Delft University of Technology in the Netherlands and the Japan Advanced Institute of Science and Technology in Ishikawa, completely bypasses this step. The collaborators detailed their findings in the 21 April online edition of the journal Applied Physics Letters.

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