5/23/15
5/20/15
GLOBAL SEA FLOOR A "VOLCANIC WONDERLAND"
NBC SCIENCE - SEAFLOOR SURVEY - VOLCANIC WONDERLAND full article including color map and video!
Compared with the previous map, from 1997, the resolution is twice as accurate overall and four times as better in coastal areas and the Arctic, said lead study author David Sandwell, a marine geophysicist at the Scripps Institution of Oceanography in La Jolla, California.
The seafloor topography comes from a gravity model of the ocean, which is in turn based on altimetry from the Jason-1 and Cryosat-2 satellites.
Compared with the previous map, from 1997, the resolution is twice as accurate overall and four times as better in coastal areas and the Arctic, said lead study author David Sandwell, a marine geophysicist at the Scripps Institution of Oceanography in La Jolla, California.
The seafloor topography comes from a gravity model of the ocean, which is in turn based on altimetry from the Jason-1 and Cryosat-2 satellites.
5/12/15
BALEEN WHALE HEARING - MYSTERY SOLVED!
DISCOVERY - BALEEN WHALES HEARING MAY BE SOLVED by Richard Farrell full article
EXCERPT:
San Diego State University biologist Ted W. Cranford and University of California, San Diego engineer Petr Krysl created a three-dimensional computer model of a baleen whale's head, one that would include the skin, skull, eyes, ears, tongue, brain, muscles, and jaws.
For their test subject, the pair obtained the head of a fin whale that beached in 2003 and then ran it through an X-ray CT scanner.
Once they had the head scan, Cranford and Krysl ran simulations of how sound travels through the whale's brain. To get the detail they needed, they used a technique called finite element modeling, in which the data representing the head parts and skull were separated out into tiny elements by the millions, the relationships between the elements tracked.
Sound can reach a baleen whale's ear bones on its skull in two ways: the sound's pressure waves can go through the animal's soft tissue; or the sounds can vibrate along the skull itself, in a process called "bone induction."
The problem with the soft-tissue, pressure, route, the researchers said, is that it's ineffective when sound waves are longer than the whale's body. But with the bone induction process, those longer waves become amplified as they vibrate in the creature's skull.
The scientists' computer modeling showed that the bone induction process was about four times more sensitive to low-frequency sounds than the soft-tissue, pressure mechanism.
What's more, their modeling predicted that bone induction is 10 times more sensitive to the lowest frequencies used by fin whales (10 Hz-130 Hz).
EXCERPT:
San Diego State University biologist Ted W. Cranford and University of California, San Diego engineer Petr Krysl created a three-dimensional computer model of a baleen whale's head, one that would include the skin, skull, eyes, ears, tongue, brain, muscles, and jaws.
For their test subject, the pair obtained the head of a fin whale that beached in 2003 and then ran it through an X-ray CT scanner.
Once they had the head scan, Cranford and Krysl ran simulations of how sound travels through the whale's brain. To get the detail they needed, they used a technique called finite element modeling, in which the data representing the head parts and skull were separated out into tiny elements by the millions, the relationships between the elements tracked.
Sound can reach a baleen whale's ear bones on its skull in two ways: the sound's pressure waves can go through the animal's soft tissue; or the sounds can vibrate along the skull itself, in a process called "bone induction."
The problem with the soft-tissue, pressure, route, the researchers said, is that it's ineffective when sound waves are longer than the whale's body. But with the bone induction process, those longer waves become amplified as they vibrate in the creature's skull.
The scientists' computer modeling showed that the bone induction process was about four times more sensitive to low-frequency sounds than the soft-tissue, pressure mechanism.
What's more, their modeling predicted that bone induction is 10 times more sensitive to the lowest frequencies used by fin whales (10 Hz-130 Hz).
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