Also on AMERICAN MOSAIC: A question from Brazil about the composer and band leader John Philip Sousa. His music is popular on the Fourth of July -- America's Independence Day.

On ECONOMICS REPORT: He leaves at a time of major changes in the computer industry. But over 90 percent of the world's one billion personal computers still use the Windows operating system.

On THE MAKING OF A NATION: Burr went on trial in 1807 for a secret plot to seize Mexico from Spain. The plan could have divided the Union. But was he guilty as charged?

On EDUCATION REPORT: Are the ceremonies a good way to recognize success in school? Or do they waste money and send the wrong message?

On HEALTH REPORT: The W.H.O. launches an effort to prevent deaths and injuries in the operating room.

On EXPLORATIONS: The spread of cell phones, computers and other technology has increased economic growth in poor countries. But such countries still have a long way to go to catch up to the developed world.

On AGRICULTURE REPORT: Researchers say species found nowhere else could be lost unless they are able to relocate by the year 2100.

On SCIENCE IN THE NEWS: Medical science has eliminated only one disease, smallpox. Bill and Melinda Gates called last year for a campaign to stop malaria. But experts differ on the idea. Some say existing measures could reduce cases by 90 percent.

On WORDS AND THEIR STORIES: English expressions that may sound fishy, but don't smell fishy.

On THIS IS AMERICA: The largest battle ever fought in North America took place in Pennsylvania 145 years ago this week.

On DEVELOPMENT REPORT: The World Community Grid is joining together individual computers to create massive processing power. The technology is helping reduce research time from years to months.

On PEOPLE IN AMERICA: He often said that sound and music were his life’s blood. In fact, he said that he would not trade his musical ability for the ability to see again. Second part of a two-part series.

On IN THE NEWS: The U.S. high court says 32-year-old Washington, DC gun ban is unconstitutional.

On ECONOMICS REPORT: Actions to deal with the effects of the recent credit crisis include legislation, rule changes and arrests.

Also on AMERICAN MOSAIC: The story behind the century-old song "Take Me Out to the Ballgame." And music by performers at the JVC Jazz Festival in New York.

On EDUCATION REPORT: Full-time virtual schools can now be found in 18 American states.

On THE MAKING OF A NATION: Samuel Chase used the courtroom as a place to attack President Jefferson's policies. Vice President Aaron Burr led the trial as chief officer of the Senate.

On EXPLORATIONS: The growth of the Internet has led to new technologies. Many are being used today to create valuable learning environments in education. Third of three reports about the Information Age.

On HEALTH REPORT: Evidence is seen for a possible cause of solid tumors, but many questions remain.

Also on SCIENCE IN THE NEWS: A study finds that people who stop smoking often influence other smokers to quit.