Q: How many police officers have died in the line of duty since records have been kept? How many in Georgia?

IRENE HOLT BARRON, Mableton

A: The Officer Down Memorial Page at www.odmp.org lists 19,123 law enforcement officers who have been killed in the line of duty. For Georgia, the total is 549.

The National Law Enforcement Officers Memorial Wall at www.nleomf.com contains the names of 18,274 officers who have died in the line of duty. Georgia deaths total 518. Memorial Wall spokesman Kevin Morison says the numbers differ because his group counts only those names inscribed on the Memorial Wall in Washington.

The first known officer killed in the line of duty was Deputy Sheriff Isaac Smith of the New York City Sheriffs Office, who was killed on May 17, 1792. May 15 is National Peace Officers' Memorial Day when additional names will be added to the Wall, and government buildings fly the flag at half staff.

Q: When did superdelegates come into being? I don't remember them in the news previously.

PHYLLIS RUDOLPH, Loganville

A: Superdelegates were created in 1982. The idea came from a commission looking at how the Democratic party nominated presidential candidates. Superdelegates voted for the first time at the 1984 Democratic National Convention.

The aim was to ensure a certain percentage of delegates to the nominating convention were themselves elected officials.

Since they had the experience of running and winning, it was hoped they'd bring a pragmatic approach to selecting the top of the ticket.

Superdelegates originally comprised about 14 percent of all delegates. Now, they're about 20 percent.

Q: Where can I donate my used cellphone to help military service members?

DAN NORRIS , Fayetteville

A: Cell Phones for Soldiers, www.cellphonesforsoldiers.com, sells donated cellphones to a company that recycles them. The money is then used to purchase calling cards that are sent to troops. Call 800-426-1031 or e-mail cellphonesforsoldiers@recellular.com for more information.

AT&T's 1,800-company-owned wireless stores are drop-off sites for used cellphones through July 2008. AT&T donates prepaid phone cards to Cell Phones for Soldiers in return for the used cellphones. Drop-off locations are listed at www.cellphonesforsoldiers.com/locateDropoff.html.

-- Researchers Joni Zeccola and Richard Hallman wrote this column.