Before the center was built, Barbosa remembers the site as an empty park.

"There wasn't anywhere for kids to go and so it was easy to see why they were hanging out in the street," says Barbosa, who is affectionately called "Mo" by local children.

Aside from offering basketball leagues, preparation for the SATs, resume workshops and educational courses, the center teaches students how to cope with problems such as racism, drug use and health-related issues.

Young women convene each Monday for "Ladies' Night" activities. About 100 children use the center during the winter each day, while good summer weather cuts daily attendance to 60 to 80.

Barbosa, who was hired as director in November, says the center's mission is to involve students in different things and to keep them off the streets.

Area Four's population is largely Haitian, Latino, Puerto Rican and Cape Verdean, according to Barbosa. Eastern European immigrants, especially from the Czech Republic, have also begun moving to Area Four recently.

In an area where over 30 percent of children live in single-parent families, the center takes on the role of parent by sponsoring Friday night dinners.

"We realized that kids weren't eating on Friday nights because their mom and dad were either out or working and the kids just accepted that as normal," Barbosa says. "That's just ridiculous."

The youth center, Barbosa says, helps students cope with problems of poor self-esteem, neglect and emotional or behavioral problems.

Area Four has the highest unemployment rate in Cambridge, 10.8 percent according to 1990 census data, and one of the lowest median family incomes of about $27,000.

A six year-old child bursts into Barbosa's office, complaining about one of the older children bothering him. "Call him in," Barbosa says.

A minute later, a wiry 13 year-old strolls into the office and leans on Barbosa's desk, ready to accept whatever sermon Barbosa metes out.

"So you're 13 years old; you have to take some responsibility," Barbosa says to the embarrassed youngster. "C'mon, I know you can do it," he adds with a smile.

Turning back to the guest, Barbosa remarks that the disruptive teenager is very interested in chess. He did well in the last tournament the center sponsored and is expected to do well once again in next week's tournament.

"He had watched chess before but never really played," Barbosa said. "And here, he discovered that he was really good at it. I guess that's what we're trying to do here."