STRANGE BUT TRUE- Broken-hearted: Diastolic flaccidity explains the pain
DRAWING BY DEBORAH DERR McCLINTOCK
Q. Why do we talk of a "broken-hearted" lover? Is the distress really felt mid-chest?– L.Taylor
A. Metaphorically, the Japanese emphasize the stomach rather than the heart, says Jon Richfield in New Scientist magazine. English speakers also describe "not having the stomach" for something. Anxieties can trigger stomach aches or "lump-in-throat" esophageal spasms. In healthy people, the muscular viscera– the stomach, esophagus, heart– call attention to themselves. Though these are under involuntary nervous and hormonal control, the physical reactions can be dramatic.
The heart reflects emotions via its intensity and rhythm, for example leaping and pounding in shock. Helplessness can bring on drastic blood pressure drop, which explains deaths in those who believe they're the target of a voodoo curse.
"Diastolic flaccidity" also explains the physical heartache of grief, loss, betrayal. In addition, it reduces circulation and causes cardiac irregularity or palpitations, with frightening symptoms such as faintness or tingling in the face and extremities. On the other hand, surges of adrenalin cause the pulse to race, stepping up blood pressure for sudden action but also risking paralyzing panic in confused circumstances.
"Compare this," Richfield writes, "to the less muscular vital organs which cannot give such immediate feedback– it takes time to interpret what the liver or kidneys have to say."
Q. Do the blind use e-mail?–S. Wonder
A. Sure, along with surfing the Internet with screen readers that capture computer text and present it in braille or aloud via synthetic speech, according to Courtney Goines and Steve Bauer of the Braille Institute of America. The blind use many of the same web sites and e-mail providers as do sighted people. Screen readers cannot interpret graphics but work well with text in almost any language. They also echo back keystrokes to ensure accurate typing and offer navigation commands for accessing desired information quickly on a web page. These are available for Windows, Mac, and Linux computers.
"Hopefully as adaptive technology for people with disabilities continues to advance, subjects like this will no longer be relegated to the strange-but-true category."
Q. How powerful is the magnet in an MRI machine?–E. Harmony
A. At 15,000 Gauss, it's 30,000 times stronger than the Earth's magnetic field, says Joseph P. Hornak, professor of chemistry and imaging science at the Rochester Institute of Technology. Credit cards or bank cards are erased. Pacemakers may be affected, and other metal implants can become dangerous internal knives. Any loose nearby oxygen tanks, mop buckets, etc. may go airborne.
The point of Magnetic Resonance Imaging is to set the hydrogen atomic nuclei of the body's water molecules moving like little toy tops. Then a radio wave jostles the tops in patterns that discriminate healthy soft tissues from unhealthy. Bones have been X-rayed for over 100 years, but only recently with MRI have muscles, nerves, and the brain been effectively laid bare.
Q. How did fruit eating become one of the fruits of the human condition?–R. Descartes
A. Long ago, protohumans needed great brain power to stay one step ahead of would-be predators. Colorful, succulent fruits delight not only our eyes and tongues but our digestive tracts as well, says McGill University researcher Daniel Levitin in The World in Six Songs. Biologists have found an amazing inverse relationship between brain size and digestive tract size, which in turn relates to food complexity: Leaf-eating primates tend to have smaller brains but larger digestive tracts than do fruit-eaters because leaves, being more difficult to digest, require more processing stages and more energy to break down into usable sugars.
On the other hand, fruit-eating takes more cognitive skills (think "bigger brains"), specifically for remembering the location of fruit-bearing trees, anticipating when they will be in season, and discerning ripe from unripe or rotten. This last requires good color vision via the occipital cortex to gauge nutritional content and digestibility. And since total energy available to an organism is limited, there is an evolutionary tradeoff between brain size and digestive tract size. Rather smartly, therefore, did we become fruit eaters some 40 million years ago.
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Send strange questions to brothers Bill and Rich at [email protected].
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