Rail stops become real-world labs for Harvard research

A Harvard study conducted on rail platforms in the Boston area found that mixing with people of different ethnic backgrounds can influence social acceptance.

Senator Edward J. Markey (left) and former NBA player Chris Herren (second from left) listened as Gil Kerlikowske, director of the Office of National Drug Control Policy, spoke about recent heroin overdoses at a press conference in Taunton.

Officials take notice of rise in heroin overdoses

Senator Edward Markey called the increase in overdoses across the region “a scourge like we have never seen before.”

//c.o0bg.com/rf/image_90x90/Boston/2011-2020/2014/02/24/BostonGlobe.com/Foreign/Images/kiev150-1373.jpg Ukraine issues warrant for former leader

Russia denounced the interim government in Kiev, even as that government moved to open a dialogue with the West.

Linda Pelletier collapsed inside the hallway of the Edward Brooke Courthouse and was taken on a stretcher to a local hospital.

DCF seeks foster care for Conn. teen in medical dispute

The mother of Justina Pelletier collapsed and was taken to a hospital on a stretcher after a court hearing about her daughter.

Musicians Julia Yang (left) and Shira Majoni.

Kayana Szymczak for The Boston Globe

Expanding minds and social circles through classical music parties

Groupmuse is a website that matches up people who want to volunteer their home for a semi-public classical musical performance with musicians and guests.

Utah’s Alec Burks took a shot as Kelly Olynyk and Brandon Bass defended.

jazz 110, celtics 98

Celtics fall to Jazz, finish another trip west winless

The Celtics have lost five straight, including four on their most recent trip to play Western Conference opponents.

Pope Francis celebrated mass at Saint Peter's Basilica on Sunday.

Pope makes first overhaul of Vatican in 25 years

Pope Francis announced the first major overhaul of the Vatican’s outdated and inefficient bureaucracy in a quarter-century.

Harold Ramis

Harold Ramis, comedy director and actor, dead at 69

Ramis, perhaps best known for his acting roles in “Ghostbusters” and “Stripes,” died Monday.

Opinion

Jennifer Graham

//c.o0bg.com/rf/image_90x90/Boston/2011-2020/2014/02/21/BostonGlobe.com/EditorialOpinion/Images/0224oped_graham2.jpg The carriage horses are fine

Never do abusers outnumber the caring, and it’s not wise to govern at the whip of extremes.

Business

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Jan Koum, chief executive officer and co-founder of WhatsApp, delivered a keynote speech at the Mobile World Congress in Barcelona.

WhatsApp to offer voice service

Relatively unknown in the US until it was acquired by Facebook for $19 billion, the messaging service has nearly double the users as Twitter.