RIO 2016

Atop the 190-foot Véu da Noiva waterfall in Mangaratiba (a municipality on the outskirts of the state of Rio de Janeiro), her prismatic "Ring: One With Nature" -- a 10-foot acrylic ring, supported by a Teflon-coated stainless steel -- appears suspended in air.

Through a trick of the light, it seems to change hue -- blue, gold, transparent -- depending on the position of the sun and viewer.

The mayor of Rio, Eduardo Paes, carried the torch on its first few laps through the city centre.

But there were chaotic scenes later in the north of the city when the torch relay was challenged by hundreds of demonstrators angry at the high cost of hosting the Games.

Riot police used tear gas and pepper spray to disperse the crowd.

Images shown on news websites showed at least one policeman appearing to fire a projectile directly at a protester.

Bolt's executive manager Nugent Walker confirmed the news, less than 20 minutes before the race.

"He, Bolt, is out of the remainder of the championship on medical exemption," Walker said.

Bolt's withdrawal does not mean he will miss the Rio de Janeiro Olympics, where he is expected to defend his titles in the 100m and 200m.

Unlike the United States, where the first three finishers in the trials win Olympic berths, Jamaica's selection policy allows medical exemptions.

The latest threat comes as Rio 2016 chief executive Sidney Levy admitted that security fears are his biggest worry ahead of the Games.

"Differently from Zika, security's at the top of my list - the very top of my list," Levy said.

"We should never forget that these days we live in a society that's very in danger."

But whether they are allowed to represent Russia or not is unclear.

IOC president Thomas Bach said clean Russian athletes should take part under their own flag.

While athletics' governing body the IAAF says it will accept appeals on an "exceptional basis", for Russians to participate as "neutral athletes".

Under the new measures, the Public Sports Authority (PSA) gain the power to dissolve all sporting bodies including the Kuwait Olympic Committee, as well as assuming control over all appointments and financial matters.

Those who refuse to comply could face jail terms of between one and three years.

The new Statutes, proposed by PSA chair Sheikh Salman Sabah Salem Al-Humoud Al-Sabah, were approved by 40 of the 46 members of the National Assembly today.

Rutherford's partner Susie Verrill told Standard Issue magazine that they harbour serious concerns over the virus, which experts say is to blame for a surge of cases in Latin America of microcephaly - a serious birth defect in which babies are born with unusually small heads and brains.

The pair, who want to have more children, are as a result taking precautions ahead of Rutherford's defence of his long jump gold medal.

Several experts have called for the Games to be postponed or moved over fears it could speed up the spread of the virus around the world.

The WHO has rejected these calls, however, claiming it would "not significantly alter" the outbreak.

They have now called an emergency meeting for later this month to re-evaluate the situation.

"The emergency Committee meeting will consider the situation in Brazil, including the question of the Olympics," said Nyka Alexander, a spokeswoman for the WHO.

Among the 50,000 volunteers taking part in the Rio 2016 Olympic and Paralympic Games will be a small group of people for whom the Olympic values of friendship and respect for others have a very special meaning: 38 refugees and asylum seekers from areas of unrest and conflict who have chosen Brazil as their new home.

For the refugees, providing valued services at the Games will help them reconnect with the outside world and build their self-esteem, after experiencing the anguish of losing their homes and leaving their friends and families behind.

The announcement comes after the International Olympic Committee (IOC) retested 454 selected doping samples from the 2008 Games in Beijing.

The IOC said the retests were conducted using the very latest scientific analysis methods.

It also revealed it is awaiting the results of 250 retests from the 2012 Olympics in London.

"All these measures are a powerful strike against the cheats we do not allow to win," IOC president Thomas Bach said.