But perhaps the most critical factor, they said, has been a city program in which workers supervise patients to make sure they take their medication.

The Canadian workers supervised, and completed tasks in office, warehouse, laundry, maintenance, utilities, cleaning service and food preparation settings.

"And, of course, social workers and court personnel will supervise the meetings, and there will be security."

In addition to providing services, these workers may supervise other workers or conduct research.

The police said about 40 Shining Path guerrillas mounted the assault on Saturday night in Llusita, a hamlet where workers were supervising the construction of a hydroelectric dam.

But the Health Commissioner, Dr. Hamburg, said the "mainstay" of tuberculosis control in the city has been a program known as directly observed therapy, in which workers supervise patients who may fail to take their medication.

For three months, workers supervised by the National Transportation Safety Board and the Federal Bureau of Investigation have meticulously pieced together some 700 chunks of wreckage from the shattered Boeing 747's midsection, the world's largest, most complicated jigsaw puzzle.

Before the end of the year, the city intends to use six times as many workers, at least 30, to supervise the treatment of tuberculosis, from five earlier this year.

Other workers supervise or support the hands-on work in some way.

The most serious problem, critics say, is that the workers who operate the metal detectors are poorly paid, transient and work for contractors that are often poorly supervised by the airlines.