Research briefs

29 August 2001 |

New way to measure Earth’s rotation developed
A novel approach to measuring slight increases and decreases in the rotation of objects, such as the Earth’s rotation, has been successfully demonstrated by a team of Berkeley physicists.

Richard Packard and Séamus Davis, both professors of physics, were able to manipulate ultra-cold liquid helium-3 in a hollow, doughnut-shaped container to produce a whistle that grew louder or softer, depending on the orientation of the helium relative to the planet’s North Pole and its rotation. In principle, the noise level will increase or decrease with changes in Earth’s slow, 24-hour rotation, which varies slightly each day.

“Our experiment was a proof of principle, but if we can reduce the noise enough and build a much larger version of the device, it is conceivable that we could make a sensor to monitor small changes in the Earth’s rotation,” said Davis, who carries out his research in the Materials Sciences Division of the Lawrence Berkeley National Laboratory. Current techniques of measuring Earth’s rotation are not sensitive enough to detect some changes caused by clouds or earthquakes, but the new technique may become a promising new method.

Opposing ideas of love may keep U.S. marriages alive
Americans seem to want contradictory things in marriage: permanent commitment and free choice. They resolve this paradox by keeping two opposite ideas of love alive, according to new research by a Berkeley professor of sociology.

One idea is a down-to-earth belief that one must work at keeping love alive through compromise, personal growth or religious faith. The other is a Hollywood movie version of love — a romantic belief in the existence of one everlasting “true” love, said Ann Swidler, author of a study of American middle class cultures of love.

In her analysis of 88 married and divorced middle class Americans from San Jose, Swidler found that people shifted back and forth between these two belief systems. Although most did not have trouble discussing the practicalities of love and commitment, not everyone readily admitted to having the romantic belief. Most of Swidler’s interviewees said that love had to be created on a daily basis through work, and that it didn’t come automatically. Many were critical of romantic “myths,” insisting that they are dangerously misleading, Swidler said.

New atomic tunneling technique developed
A new scanning tunneling microscope, designed to measure the counterclockwise spin-up or spin-down rotation of a single atom, has given Berkeley scientists their first look at the weird electrical interactions of a high temperature superconductor. Soon, the new technique may give them a look at the spin states of atoms in metals and semiconductors, as well as in new materials, such as carbon nanotubes.

Until now, researchers have resorted to trapping isolated atoms and zapping them with a laser to measure their spin states. This new technique, reported in the June 21 issue of Nature by a group including Séamus Davis, a Berkeley professor of physics and researcher in the Materials Sciences Division of Lawrence Berkeley National Laboratory, will not only improve scientists’ understanding of high temperature superconductors, but help advance the field of quantum computing.

Scientists predict that quantum computers taking advantage of two-level quantum states like this will be able to perform calculations far faster than conventional transistor-based computers, and in the process shrink the size of computers immensely.

Outdoor fantasy play speeds kids’ cognitive development
It’s outdoor play, not just classroom learning, through which young children learn best, according to Jane Perry, a Berkeley researcher in early child development.

Self-directed fantasy play in the yard is an essential feature in young children’s cognitive and psychosocial development, says Perry, who is a research coordinator at the Harold E. Jones Child Study Center, a full-time campus child care facility and a research unit in the Institute of Human Development.

During outdoor play, children are keenly aware of each other. Their fantasy games can be used by teachers to advance learning in many areas including linguistic, spatial and social skills, she suggests in “Outdoor Play: Teaching Strategies with Young Children,” published in June by Teachers College Press, Columbia University.

DNA changes understanding of two Mexican salamanders
They aren’t kissing cousins. In fact, the salamanders discovered in an isolated range of hills in southeastern Mexico, which were thought to be a close relative of a species living in mountain foothills several hundred miles away, are a distinct species, as genetically different as a horse is from a cow.

Campus zoologists reported their discovery after completing a DNA analysis. The results demonstrated an evolutionary concept called “parallelism,” wherein two organisms independently develop the same adaptation to a particular environment. Researchers conducting DNA analysis often discover that what once were thought to be separate populations of the same species are, in fact, two separate species.

“Biodiversity has been grossly underreported,” said David Wake, professor of integrative biology and co-author of the new study.

Scientists debut world’s smallest laser wire
One of the world’s smallest lasers — called a “nanowire nanolaser” — that is one thousand times thinner than a human hair has been produced by a team of researchers at Berkeley and the Lawrence Berkeley National Laboratory.

The device, which emits flashes of ultraviolet light has potential applications in such fields as photonics and optical computing, where cheap bright lasers are essential to transmitting laser light. Other applications, according to creator Peidong Yang, a Berkeley assistant professor of chemistry and member of the Lawrence Berkeley National Laboratory, may include the development of high-density information storage and microchips.

The tiniest solid-state lasers in use today are fashioned from thin films of either gallium arsenide or gallium nitride and generally run several microns thick, or about one hundred thousandths of an inch. Once the scientists have perfected their technique for growing these tiny, bristle-like nanowires, the new technology could be developed for super fast data processing and transmission, or for development of the so-called “lab on a chip,” a microchip that is equipped with nano-sized light sources and sensors, to perform instant and detailed analyses in chemistry, biology and medicine.


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