“I was scared to death,” said Ms. Papapietro, 21, a senior at Monmouth University who works at a public relations firm in Manhattan. “I kind of trust New Jersey Transit to get me back and forth, and I really hope this doesn’t happen again.”

Yet doors on New Jersey Transit trains have opened improperly at least four other times in the past two months, far more frequently than on moving Metro-North or Long Island Rail Road trains.

Then in February, as a train left the North Elizabeth station during the evening rush, the third and fourth cars uncoupled, leaving hundreds of passengers in cars not attached to an engine.

While New Jersey Transit says that the problem of malfunctioning doors is not widespread, these isolated incidents have shaken employees and riders alike.

. . .

Riders are routinely told not to stand between cars, but feel compelled to do so during peak hours when cars are so crowded that it is standing- room-only and conductors cannot make their way through the aisle to collect fares.

When questioned, rail industry consultants said they wondered whether New Jersey Transit is cutting corners on maintenance, or is stretched too thin as it tries to keep up with record demand.

Officials said that about 250 cranes were now in operation in the five boroughs, a telling sign of the city’s building boom. Construction cranes are towering behemoths, signposts of the city’s prosperity that dominate the skyline for months but often go unnoticed.

Yet on Sunday, those who lived, worked or happened to be walking near the cranes looked upward with anxiety, their nerves rattled by Saturday’s collapse.

A gas station cashier who works below a crane at West 24th Street and 10th Avenue said he trusted God to protect him. A neighbor who lives across the street, Ana Gonçalves, puts her faith in the builders and hopes they know what they are doing. Victor Simpkins, another neighbor, has watched the crane for weeks, but now he looks up at it with a new suspicion.

“If that thing would fall over, my building would be toast,” said Mr. Simpkins, 53, a designer and filmmaker.

. . .

Mayor Michael R. Bloomberg acknowledged the danger of high-rise construction, but said residents near cranes were generally safe. “Do I think that you should worry if there’s a crane across the street?” the mayor said at a news conference on Sunday. “No. This is such a rare thing that I don’t think we should worry about it.”

But as cranes have proliferated, so, too, have accidents associated with them. Last year, there were eight crane-related “accidents,” up from five in 2006; and 21 crane-related “incidents,” up from 14. As the city’s Department of Buildings defines them, “accidents” involve fatalities or injuries, and “incidents” do not.

The collapse of the 205-foot crane on Saturday — described by city and union officials as one of the worst crane accidents in memory — gave rise to a grim New York City parlor game, one that pedestrians have doubtlessly played in the back of their minds over the years: If that crane fell, where would it hit?

“We thought about it, and we think if it falls, it will probably fall into the park or bounce off that clock tower,” said Jarrod Shandley, 25, who lives with two roommates in a penthouse that looks out onto a crane at East 23rd Street and Madison Avenue.

. . .

By the time the sliding doors parted and she walked in at noontime on Wednesday, she had also heard about laboratory tests that found high levels of mercury in tuna bought at 20 Manhattan stores and restaurants, including the Gourmet Garage. Its tuna had the second-highest mercury level in the study, 1.25 parts per million.

She bought 12 pieces of tuna sushi anyway.

Today, the federal government is announcing that it has completed the mid-Atlantic region’s risk assessments for the killer mounds of water known as tsunamis, or tidal waves.

Scientists have long considered the West Coast of North America as the side of the continent most likely to suffer earthquakes and the undersea disturbances that raise tsunamis. But in recent years, with a growing appreciation of the diverse origins of the giant waves and their potential for havoc, experts have found new reasons for vigilance along the East Coast.

“Tsunamis are a real threat,” said Lisa Taylor, an official at the National Oceanic and Atmospheric Administration, which is conducting the assessments for coastal regions that are considered at risk. A main factor is whether the land rises sharply or gently, the latter being more prone to poundings from unexpectedly high waves.

The project creates elevation maps of coastal lands and adjacent seafloors, helping scientists better forecast the areas that a tsunami would flood. The giant waves can arise hundreds of miles away, in theory giving emergency planners hours to send people to higher ground.

A Wagner College student came down with MRSA and a high school student at St. Joseph by-the-Sea has been rumored to have a drug-resistant strain of the infection, though officials at the Huguenot school have not confirmed that case.

A Wagner College spokesman confirmed yesterday that a student at the Grymes Hill campus had been diagnosed last week with MRSA, which often manifests as a skin infection and is resistant to most, but not all antibiotics. Officials there issued a campus-wide e-mail recently and mailed a letter to parents stating that a student had been found to have had the infection.