After a quarter-century of searching, scientists have nailed down how one particularly rare subatomic particle decays into something else — a discovery that adds certainty to our thinking about how the universe began and keeps running.

The world's top particle physics lab said Friday it had measured the decay time of a particle known as a Bs (B sub s) meson into two other fundamental particles called muons, which are much heavier than but similar to electrons. It was observed as part of the reams of data coming from CERN's $10 billion Large Hadron Collider, the world's largest atom smasher, on the Swiss-French border near Geneva.

A landmark federal study on hydraulic fracturing, or fracking, shows no evidence that chemicals from the natural gas drilling process moved up to contaminate drinking water aquifers at a western Pennsylvania drilling site, the Department of Energy told The Associated Press.

After a year of monitoring, the researchers found that the chemical-laced fluids used to free gas trapped deep below the surface stayed thousands of feet (1,000 feet equals 300 meters) below the shallower areas that supply drinking water, geologist Richard Hammack said.

Hundreds of supporters greeted the charismatic Russian opposition leader Alexei Navalny as he returned to Moscow on Saturday after his surprise release from jail and vowed to push forward with his campaign to become mayor of the Russian capital.

Navalny was sentenced to five years in prison on an embezzlement conviction on Thursday in the city of Kirov, but prosecutors unexpectedly asked for his release the next morning. They said that keeping him behind bars during the appeals process of his conviction would deprive him of his right to run for office.

Portuguese rider Rui Costa won the mountainous 19th stage of the Tour de France with a solo breakaway on the final climb, while race leader Chris Froome was still descending to the finish.

Costa secured his second stage win of the race after catching Frenchman Pierre Roland about a quarter of the way up Friday's fourth and final major ascent of Col de la Croix Fry.

Fans will pay a standard $90 for tickets to see World Cup matches in Brazil next year, $10 more than in 2010 in South Africa.

Announcing ticket rates Friday, FIFA said $15 seats will be available to Brazilian students, people over 60 and members of social programs. In 2010, South African residents could pay $20.

Italian World Cup-winning defender Gianluca Zambrotta has joined Chiasso in the Swiss League second division.

Chiasso announced in a statement that the 36-year-old Zambrotta has signed a one-year contract and will also work as an assistant coach.

After five grueling hours of riding, as he strained and sweated to victory in an eye-popping Tour de France stage with crowds that turned cycling's most famous climb into a huge and raucous high-mountain party, Christophe Riblon didn't want it to stop.

Winning a Tour stage is always special.

AmaZulu beat Manchester City 2-1 with an 89th-minute penalty on Thursday and left last season's Premier League runner-up with two losses from two games on its pre-season tour of South Africa.

Carlington Nyadombo hit the winner from the spot after the South African top-flight team led in the 20th minute through striker Bongani Ndulula. James Milner equalized at Durban's Moses Mabhida World Cup stadium with a crisp volley six minutes later, City's first goal on tour.

Former Australia coach John Buchanan has resigned as New Zealand's director of cricket, continuing a major shakeup in the sport's management and administration.

While local media blamed the breakdown of his relationship with national coach Mike Hesson, Buchanan said on Friday he is leaving the position after two years for family reasons.

The young stars of Disney Channel's new "Teen Beach Movie" enjoyed putting on the '60s two-piece bikinis a la Annette Funicello so much they wanted to keep them. They also swooned over cheerful prints and crushed on high-waist shorts.

The movie debuts Friday, just in time for the important back-to-school season.