N.Y.C.’s mayor says a new virus rule will reduce temporary public school closures.

Mayor Bill de Blasio of New York City announced a plan on Thursday that he said would significantly reduce the temporary public school closures that have frustrated parents and educators across city over the last few months.

Starting on Monday, public schools will have to close for 10 days only if four or more coronavirus cases in separate classrooms are confirmed within a seven-day period, and only if the city’s contact tracing program determines that the infections originated inside the school. Until now, schools had to close for 10 days when two unlinked cases were detected, regardless of the source

Looking to Travel for a Sense of Renewal

Svetlana Reznikova-Steinway, an emergency-room physician who lives in Phoenix, has spent the better part of a year pulling double-duty in an overwhelmed intensive care unit. Early in the pandemic, she and her husband, a urologist, developed a system for after work, stripping off their scrubs in their garage to protect their 12-year-old daughter and 10-year-old twin sons from the virus. She has gotten used to intubating critically ill Covid-19 patients. She has learned how to delicately use patients’ phones to FaceTime family members so that everyone can say their goodbyes.

“It’s been horrific,” Dr. Reznikova-Steinway, 43, said. “My colleagues and

A Tiny Particle’s Wobble Could Upend the Known Laws of Physics

At Fermilab, a new campus devoted to studying muons was being built.

“That opened up a world of possibility,” Dr. Polly recalled in his biographical article. By this time, Dr. Polly was working at Fermilab; he urged the lab to redo the g-2 experiment there. They put him in charge.

To conduct the experiment, however, they needed the 50-foot magnet racetrack from Brookhaven. And so in 2013, the magnet went on a 3,200-mile odyssey, mostly by barge, down the Eastern Seaboard, around Florida and up the Mississippi River, then by truck across Illinois to Batavia, home of Fermilab.

The magnet …