Charles D. Keeling, 77, a scientist whose measurements showing a carbon-dioxide buildup in the atmosphere helped trigger fears of global warming, died Monday in Hamilton, Mont., after a heart attack.
A pioneer in demonstrating that increased emissions of greenhouse gases could change the environment, he began collecting air samples in 1955 to measure their carbon dioxide content. His measurements over the decades that followed showed that carbon dioxide levels were steadily rising, a finding that shattered the conventional wisdom that the Earth could soak up rising fossil fuel emissions without harm.
Charles Kennel, director of the Scripps Institution of Oceanography, with which Dr. Keeling was affiliated, called his measurements "the single most important environmental data set taken in the 20th century."
In 2002, President Bush selected Dr. Keeling for the National Medal of Science, the nation's highest award for lifetime achievement in scientific research.
"His research on the increase of carbon dioxide in the atmosphere, known to influence the greenhouse effect, established him as one of the world's leaders in environmental science," said Marye Anne Fox, chancellor at the University of California, San Diego, where Dr. Keeling was on the faculty.
Dr. Eugene Stead Jr., 96, a medical educator who created the nation's first program for physician assistants at Duke University, died June 12 at his home in Bullock, N.C.
In the 1960s, as chairman of the department of medicine at Duke University Medical Center, Dr. Stead was one of several medical educators who recognized that trained people who lacked a complete medical education could perform many clinical services and offer valuable assistance to overworked doctors. The first graduates of the two-year program, which he started in 1965, were former Navy hospital corpsmen.
"Dr. Stead was a profoundly original thinker," said Dr. Barton Haynes, a professor of medicine at Duke and a longtime colleague. "When folks were coming back from the Vietnam War, everyone saw that they needed jobs, but he saw that those who had been in the medical corps could play a role as a new type of caregiver. He was the one who made that happen."
Dr. Stead's faith in the possibilities of the new profession helped it overcome regulatory and philosophical resistance from some in the health care field.
Currently, more than 100 programs train physician assistants and 50,000 licensed practitioners, who conduct physicals, prescribe medications, order and interpret diagnostic tests, and provide clinical care, among other responsibilities.
In a 2000 article, Dr. Stead was quoted as saying that "a person with a high school education, a reasonable rate of learning and a tolerance of the unavoidably irrational demands often made by sick people can learn to do well those things a doctor does each day."
Dr. Stead was also known for his groundbreaking studies of cardiac catheterization and congestive heart failure. He was an early proponent of the role that computer analysis could play in medical practice, and he helped to develop a research database that evolved into the Duke Clinical Research Institute, which today maintains diagnostic and treatment data on more than 250,000 patients.
Billy Bauer, 89, a jazz guitarist who worked with Lennie Tristano, Benny Goodman and Charlie Parker, died June 17 in Melville, N.Y., of pneumonia complications.
Mr. Bauer developed much of his solo technique while playing with Tristano's group, which he joined in 1946. Before that, he had played mostly rhythm parts.
Mr. Bauer recorded with the Tristano band and with members including saxophonists Lee Konitz and Warne Marsh. He founded a publishing company, William H. Bauer Inc., to publish his compositions and those of Tristano, Konitz and Marsh.
He went on to work with Goodman and Parker, and in 1956 recorded one album, Plectrist, as bandleader.
As the jazz recording industry began to fade, Mr. Bauer switched to teaching, opening the Billy Bauer Guitar School in 1970. He continued teaching until shortly before his death.
He wrote an autobiography, Sideman.
William Fenton, 96, a nationally recognized scholar of Iroquois culture and former director of the New York State Museum, died June 17 in Cooperstown, N.Y.
He began studying the Iroquois in the 1930s, when he lived with the Senecas on the tribe's reservations in western New York.
He became fluent in the Iroquois language and was praised by the Indian tribes for helping preserve their culture. He also published several books, which are considered the definitive works on the customs and ceremonies of the Six Nations of the Iroquois Confederacy.
Mr. Fenton was a senior ethnologist for the Smithsonian Institution in the 1950s before joining the New York State Museum in Albany, where he became director.
He frustrated some tribes by not returning artifacts, insisting that museums were necessary safeguards for the items. Some Indian leaders were upset with Mr. Fenton for writing about rituals they considered sacred.
Albert R. Kahn, 98, an inventor who co-founded Electro-Voice Inc., a pioneering company in audio technology, died June 15 in Cassopolis, Mich.
In 1940, Electro-Voice revolutionized tank and aircraft communications by introducing the noise-canceling microphone to the U.S. military. The technology, still in use, allows users to speak in their normal voices while background noise is reduced.
The company invented the stereo magnetic phono cartridge in 1957. Six years later, it received the first Academy Award for an audio product, a shotgun microphone that improved the quality of sound recorded to film.
Mr. Kahn was president of the company from its founding until 1969, when Gulton Industries Inc. acquired it. In 1970, he co-founded radio equipment maker Ten-Tec Inc. in Sevierville, Tenn., and remained involved with the business until his death.
Guillermo Suarez Mason, 81, a former Argentine junta commander who was under arrest in connection with investigations into suspected illegal adoptions dating to the 1976-1983 dictatorship, died Tuesday.
As former commander of Argentina's 1st Army Corps, General Suarez Mason faced an investigation into accusations of illegal adoptions of children born to women detained during the dictatorship.
Earlier, he was investigated by courts looking into the 1980 disappearances of about 20 armed leftist guerrillas during the military's systematic crackdown on dissent, known as the Dirty War.
General Suarez Mason was commander of the 1st Army Corps from 1976 until 1979, at the height of the state's crackdown on dissent. The corps had command of Zone One, including the capital and populous outlying areas, at a time when human rights groups claimed that dozens of clandestine torture centers operated there illegally.
Officially, about 12,000 people died or disappeared in the military junta's campaign against leftists and other dissidents. Human rights groups put the toll at nearly 30,000.