UC Santa Cruz Tip Sheet September 1994

Research news and feature ideas, issued quarterly by the UCSC Public Information Office. For photos, releases, or other information, call Robert Irion or Jennifer McNulty at (408) 459- 2495.

Astronomy

Keck and HIRES take the temperature of a much younger universe

The Keck Telescope and its main observing tool, the high- resolution spectrograph (HIRES), are proving their power with precise measurements of astronomical objects previously beyond reach. The latest coup: a reading of the universe's temperature when it was only about one-fourth of its current age.

University of Hawaii astronomers teamed with UCSC's Steven Vogt, designer of HIRES, and others to examine carbon atoms in a distant cloud of gas. The cloud, invisible from earth, lies between earth and an even more remote quasar. Atoms and molecules in the cloud absorb parts of the quasar's light, leaving a faint spectral fingerprint that Keck and HIRES can discern. In particular, some carbon atoms change their structures slightly in response to the universe's background glow, revealing the temperature around the cloud.

Today, that background temperature is about 2.7 K (2.7 degrees above absolute zero). At the enormous distance of the gas cloud-- closer in time to the universe's fiery birth--the temperature was about 7.4 K, the researchers found. That meshes nicely with the Big Bang theory, which predicts a temperature of about 7.6 K at the cloud's redshift of 1.776. However, other cosmological models predict a similar warmth at that distance. The predictions of various theories diverge only at much greater distances, when the universe was younger and warmer still.

"This was right on, but we'd like to get out to a redshift of 3 or 4--we might be able to distinguish among cosmological models at that point," says Vogt. He and his collaborators published their results in the September 1 issue of Nature. Contact: Steven Vogt--(408) 459-2151 or vogt@lick.ucsc.edu.

Speech comprehension

Lab explores the role of visible cues in speech with computerized "talking head"

Spoken language is a universal means of communication, yet relatively little is known about how people comprehend speech. Auditory cues clearly play a role, with variables such as pitch, duration, and loudness contributing to the understanding of verbal messages. But researchers at UCSC are exploring another aspect of verbal communication: visible speech. Led by psychologist Dominic Massaro, the team is investigating the critical role played by what we see when we listen, as well as what we hear.

Massaro's team has developed sophisticated computer technology to study how people perceive and recognize speech by eye and how they combine these perceptions with what they hear. The centerpiece: a computerized "talking head" that produces synthetic speech, enabling researchers to isolate visual and auditory cues received by listeners.

The 3-D computerized image resembles a mannequin, with eyes, brows, and mouth that move in real time. The underlying grid allows researchers to control about 60 parameters to animate the face and create the movements of speech. Using the computer to produce auditory synthetic speech gives the researchers control that is not always possible with natural speech. The animated face allows them to manipulate the precise movements of the face-- including jaw, lips and tongue--that make up the visible components of speech. Synthetic speech also allows researchers to produce novel sounds or ambiguous syllables--precisely halfway between "ba" and "da," for example.

"You've probably heard elderly friends say that they hear the television better with their glasses on," says Massaro. "That's because visual cues are important to our ability to understand speech." Potential applications of the talking head include visual aids for the hearing impaired. Contact: Dominic Massaro--(408) 459-2330 or massaro@fuzzy.ucsc.edu.

Environmental policy

Recycled-paper mills produce fewer toxics than mills using virgin wood

Producing recycled paper is dramatically cleaner for the environment than making paper products from virgin-wood fiber, according to a study by Daniel Press, environmental policy analyst at UCSC. Press found that relative to mills using virgin wood, recycled- paper mills generate a fraction of the toxic substances such as chlorine, chloroform, ammonia, acids, and solvents that are commonly released in paper manufacturing.

Although the number of mills producing recycled paper remains relatively small industrywide, the environmental impact of paper manufacturing could be greatly improved through the use of recovered wastepaper, Press concluded. He based his study on data reported to the Environmental Protection Agency by pulp and paper manufacturers from 1987 to 1992.

"The pulp and paper industry has been one of the dirtiest industries in the country," says Press, who spoke September 1 at a meeting of the American Political Science Association in New York. "This study confirms the problems faced by the industry, but it also shows the enormous improvement that is possible with new technology and manufacturing processes."

Press studied self-reported statistics for pulp mills and integrated mills, which produce both paper and pulp. When he compared the toxics produced per 100 tons of finished product--a small mill's typical daily output--he found that integrated mills using recycled paper released 3 to 100 times fewer pounds of toxics on average than mills using virgin wood. For instance, integrated mills using recycled paper released 0.1 pounds of chlorine on average for every 100 tons of product, versus 4.2 pounds for integrated mills using virgin wood and 10.6 pounds for pulp mills using virgin wood. For every chemical on the EPA list, recycled- paper mills were "cleaner" than virgin-wood mills. Contact: Daniel Press--(408) 459-3263 or dpress@cats.ucsc.edu.

Environmental toxicology

Controls of lead emissions, especially ban on leaded gas, help to clean the ocean

Ocean waters at the border between California and Mexico contained far less lead in the late 1980s than in the mid 1970s despite substantial increases in population and sewage disposal, according to research by UCSC scientists.

Geochemists Sergio Sanudo-Wilhelmy and Russell Flegal found three times less lead in seawater collected at the border in 1988 than other researchers had measured near the same spot in 1973. They attribute this decline to strict controls in the U.S. over lead emissions into the environment, especially the ban against leaded gasoline.

The team's study also reveals that further down the coast of Baja California, most of the lead in the water comes not from the U.S. but from increasing Mexican emissions. Although the levels of lead in the ocean are now low, they could rise off Mexico and in other parts of the globe as developing countries burn more and more leaded gas, the researchers warn.

"Industrialized countries are controlling their release of lead into the environment, and it's having an effect--the ocean is responding and cleaning itself over very short time scales," says Sanudo-Wilhelmy. "But we don't know what the effects will be from Third World countries. Their lead inputs could start being more of a problem." Sanudo-Wilhelmy and Flegal published their findings in the August issue of the journal "Geochimica et Cosmochimica Acta." Contacts: Sergio Sanudo-Wilhelmy--(516) 632-8615 or Russell Flegal--(408) 459-2093 (no email).

History of science

New research examines the progress of scientific insight by Newton and Hooke

How much did Isaac Newton know, and when did he know it? Although Newton is one of history's most famous scientists, the answers are not always clear. More than 300 years after he wrote his Principia, the foundation for much of modern science, historians still disagree about how Newton progressed from the mythical falling apple to his laws of motion and gravitation. Related questions exist about Robert Hooke, a remarkable scientist and contemporary of Newton whose ideas may have contributed to Newton's success.

Now, UCSC physicist Michael Nauenberg has joined this debate. Nauenberg examined bits of evidence that other historians have not appreciated fully: original diagrams by Newton and Hooke. He has shown that two obscure diagrams in particular, one by each scientist, reveal a wealth of details about the extent and time frame of their understanding of how planets orbit the sun.

According to Nauenberg, one diagram--seemingly drawn sloppily in the margin of a letter from Newton to Hooke--shows that Newton may have understood orbital dynamics earlier than historians have assumed, at least eight years before he published the Principia in 1687. The other, an apparent forest of lines and arcs that Hooke never published, may point to a deeper and more accurate knowledge of orbital motions than historians have credited to Hooke.

"Newton has always been an enigma," says Nauenberg. "When I came upon this diagram and looked for an explanation of how he could have derived it, I kept running into blank walls. The second diagram, by Hooke, was a total revelation to me. According to historians of science, Hooke was not supposed to have possessed these insights at all." Nauenberg's work, still in progress, appeared in three different journal articles earlier this year. Contact: Michael Nauenberg--(408) 459-2736 or michael@mike.ucsc.edu.

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