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The Brown University News Bureau

1997-1998 index

Distributed June 2, 1998
Contact: Carol Cruzan Morton

Five story ideas in science, environment and technology

• Eavesdropping on the Earth at a mid-ocean ridge in the South Pacific
• The menopause evolution debate: No evidence for "grandmother hypothesis"
• Tadpole hearing may provide model for fetal hearing development.
• You make my heart sing: Healthy hearts generate the most pleasing music.
• New technology lets teleconferencing cameras switch automatically among speakers.

New picture emerges of underground magma at separating seafloor

For the first time, seismologists have captured detailed images of the deep underground processes that give birth to most of the planet's new surface along mid-ocean ridges where the seafloor pulls apart. Early results from one of the largest marine geophysical experiments ever undertaken suggest that the separating seafloor guides magma up to the mid-ocean ridge, where it erupts and cools to form new oceanic crust. Seismologists from Brown and five other institutions reported the first detailed look at these mid-ocean upper-mantle processes in the May 22 issue of Science.

Menopause for kids, not grandkids, researchers say

Menopause has been theorized as an adaptation of evolution that allows older females to help their offspring raise a third generation. But a recent study published in the journal Nature found no evidence for this "grandmother hypothesis" in 35 years of data on birth, death and fertility among populations of baboons and lions in Tanzania. Lead author Craig Packer, ecology professor at the University of Minnesota, and co-author Marc Tatar, assistant professor of ecology and evolutionary biology at Brown University, say their data fit the theory that reproductive decline begins once a mother can no longer expect to successfully carry a new infant to its reproductive maturity.

Say what? Tadpole hearing may provide model for fetal hearing development

Tadpoles can hear, except for a brief period during metamorphosis when they go deaf, as their auditory systems rewire for adulthood. Until the recent paper by Brown University researchers in the Proceedings of the National Academy of Sciences, scientists had assumed tadpoles were deaf, even though it's well known that adult frogs rely greatly on their sense of hearing to catch food, to find mates and to defend their territories. Postdoctoral researcher Seth Boatright-Horowitz and Andrea Simmons, professor of psychology and neuroscience, speculate that tadpole hearing may provide a model for understanding how hearing develops in fetuses in the womb.

Musical mappings of the heartbeat

From heartache to heartthrob, the human heart has inspired a lot of music, but Brown University senior Zachary Goldberger may be the first to use heartbeats as the melodic template for composition. He and his colleagues mathematically transposed the heart rhythms from 15 people into melodies. Goldberger found a "dance-like plasticity and variability" in the beats, which he attributes to the inherent complex mathematical structure in the time intervals from beat to beat, known as a fractal, which describes a wide range of natural phenomenon. Pathological hearts lose this fractal nature, while healthy hearts fluctuate more widely in time and melody. Using the professional name Zach Davids, Goldberger released a compact disc recording of "Heartsongs" two years ago, and he helped create an exhibit at the Boston Museum of Science that translates a visitor's heartbeat into notes.

Voice activated camera automatically tracks speakers in video conference calls

Speak and you shall be seen is the concept behind a camera that automatically tracks who speaks during a meeting. Patents and an exclusive licensing agreement for technology developed at Brown allow computer-based computations to determine a talker's location from data acquired through an array of microphones spaced closely or far apart. The technology was invented by Harvey Silverman, dean and professor of engineering at Brown, and his former student Michael Brandstein, a professor of engineering at Harvard University who earned a doctorate at Brown.