It takes only a tiny magnetic field to see clear through a person’s head, a new study shows. A method called ultra-low field magnetic resonance imaging (MRI) has captured its first, blurry shots of a human brain, revealing activity as well as structure.
MRI scanners image the human body by detecting how hydrogen atoms respond to magnetic fields. They typically require fields of a few tesla—about 10,000 to 100,000 times stronger than the Earth’s magnetic field. The powerful magnets necessary make scanners pricey and also dangerous for people with metal implants.
The new device hits a sample with a 30 millitesla magnetic field, about 100 times weaker than is normally used in MRI. The device then uses a 46 microtesla magnetic field—about the same as the Earth’s magnetic field—to capture images of the sample.
The first target for the device was the head of lead researcher Vadim Zotev of Los Alamos National Laboratory in New
A. 10,000 to 100,000 times stronger than the Earth’s magnetic field.
B. 100 times weaker than the Earth’s magnetic field.
C. 100 times weaker than is normally used in MRI.
D. the same as the Earth’s magnetic field.
Video games have become increasingly realistic, especially those involving armed combat. America’s armed forces have even used video games (1) recruitment and (2) tools. But the desire to play games is not the (3) why the United States Air Force recently (4) a procurement request for 2,200 Sony PlayStation 3 (PS3) video-game consoles. It intends to link them (5) to build a supercomputer that will (6) Linux, a free, open-source operating system. It will be used for research, including the development of high-definition imaging systems for radar, and will cost around one-tenth as much as a conventional supercomputer. The air force has already built a smaller computer (7) a cluster of 336 PS3s.
This is merely the latest example of a(n) (8) trend. There is a long tradition of technology developed for military use filtering (9) to consumer markets: satellite-navigation systems (10)
A. available
B. incredible
C. inevitable
D. negligible
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