Irrfan Khan breaks silence, says he has NeuroEndocrine Tumour

London, May 20: The current physical distancing guidelines of 6 feet may be insufficient to prevent COVID-19 transmission, according to a study which says a mild cough in low wind speeds can propel saliva droplets by as much as 18 feet.

Researchers, including those from the University of Nicosia in Cyprus, said a good baseline for studying the airborne transmission of viruses, like the one behind the COVID-19 pandemic, is a deeper understanding of how particles travel through the air when people cough.

In the study, published in the journal Physics of Fluids, they said even with a slight breeze of about four kilometres per hour (kph), saliva travels 18 feet in 5 seconds.

"The droplet cloud will affect both adults and children of different heights," said study co-author Dimitris Drikakis from the University of Nicosia.

According to the scientists, shorter adults and children could be at higher risk if they are located within the trajectory of the saliva droplets.

They said saliva is a complex fluid, which travels suspended in a bulk of surrounding air released by a cough, adding that many factors affect how saliva droplets travel in the air.

These factors, the study noted, include the size and number of droplets, how they interact with one another and the surrounding air as they disperse and evaporate, how heat and mass are transferred, and the humidity and temperature of the surrounding air.

In the study, the scientists created a computer simulation to examine the state of every saliva droplet moving through the air in front of a coughing person.

The model considered the effects of humidity, dispersion force, interactions of molecules of saliva and air, and how the droplets change from liquid to vapour and evaporate, along with a grid representing the space in front of a coughing person.

Each grid, the scientists said, holds information about variables like pressure, fluid velocity, temperature, droplet mass, and droplet position.

The study analysed the fates of nearly 1,008 simulated saliva droplets, and solved as many as 3.7 million equations.

"The purpose of the mathematical modelling and simulation is to take into account all the real coupling or interaction mechanisms that may take place between the main bulk fluid flow and the saliva droplets, and between the saliva droplets themselves," explained Talib Dbouk, another co-author of the study.

However, the researchers added that further studies are needed to determine the effect of ground surface temperature on the behaviour of saliva in air.

They also believe that indoor environments, especially ones with air conditioning, may significantly affect the particle movement through air.

This work is important since it concerns safety distance guidelines, and advances the understanding of the transmission of airborne diseases, Drikakis said.

Belgrade, June 23: Novak Djokovic tested positive for the coronavirus on Tuesday after taking part in a tennis exhibition series he organized in Serbia and Croatia.

The top-ranked Serb is the fourth player to test positive for the virus after first playing in Belgrade and then again last weekend in Zadar, Croatia.

His wife also tested positive. “The moment we arrived in Belgrade we went to be tested. My result is positive, just as Jelena's, while the results of our children are negative," Djokovic said in a statement.

Djokovic has been criticized for organizing the tournament and bringing in players from other countries amid the coronavirus pandemic.

Viktor Troicki said Tuesday that he and his pregnant wife have both been diagnosed with the virus, while Grigor Dimitrov, a three-time Grand Slam semifinalist from Bulgaria, said Sunday he tested positive.

Borna Coric played Dimitrov on Saturday in Zadar and said Monday he has also tested positive. There were no social distancing measures observed at the matches in either country and Djokovic and other players were seen hugging each other and partying in night clubs and restaurants after the matches.

 “Everything we did in the past month, we did with a pure heart and sincere intentions,” Djokovic said.

“Our tournament meant to unite and share a message of solidarity and compassion throughout the region.” Djokovic, who has previously said he was against taking a vaccine for the virus even if it became mandatory to travel, was the face behind the Adria Tour, a series of exhibition events that started in the Serbian capital and then moved to Zadar.

He left Croatia after the final was canceled and was tested in Belgrade. The statement said Djokovic was showing no symptoms.

Despite the positive test, Djokovic defended the exhibition series. “It was all born with a philanthropic idea, to direct all raised funds towards people in need and it warmed my heart to see how everybody strongly responded to this,” Djokovic said.

"We organized the tournament at the moment when the virus has weakened, believing that the conditions for hosting the Tour had been met. “Unfortunately, this virus is still present, and it is a new reality that we are still learning to cope and live with.”

Djokovic said he will remain in self-isolation for 14 days and also apologized to anyone who became infected as a result of the series. Organizers of the Adria Tour said the third stage of the event, scheduled to held next week in Bosnia, has been cancelled.

Beijing, Feb 18: Police in China have arrested a prominent activist who had been a fugitive for weeks and criticised President Xi Jinping's handling of the coronavirus epidemic while in hiding, a rights group said Tuesday.

Anti-corruption activist Xu Zhiyong was arrested on Saturday after being on the run since December, according to Amnesty International.

China's ruling Communist Party has severely curtailed civil liberties since Xi took power in 2012, rounding up rights lawyers, labour activists and even Marxist students.

The death this month of a whistleblowing doctor who was reprimanded by police for raising the alarm about the deadly new virus before dying of it himself triggered rare calls for political reform and freedom of speech.

The "Chinese government's battle against the coronavirus has in no way diverted it from its ongoing general campaign to crush all dissenting voices," said Patrick Poon, China researcher at Amnesty International, in an emailed statement.

Another source, who spoke to news agency on the condition of anonymity, said Xu had been arrested in the southern city of Guangzhou.

Guangzhou police did not respond to requests for comment.

Xu went into hiding after authorities broke up a December gathering of intellectuals discussing political reform in the eastern coastal city of Xiamen in Fujian province, prior to the coronavirus crisis.

Over a dozen lawyers and activists were detained or disappeared after the Xiamen gathering, according to rights groups -- and Xu's detention appears linked to his presence at the meeting, explained Poon.

But while on the run, Xu continued to post information on Twitter about rights issues.

On February 4 Xu released an article calling on Xi to step down and criticised his leadership across a range of issues including the US-China trade war, Hong Kong's pro-democracy protests and the coronavirus epidemic, which has now killed nearly 1,900 people.

"Medical supplies are tight, hospitals are filled with patients, and a large number of infected people have no way to be diagnosed," he wrote. "It's a mess."

"The coronavirus outbreak shows just how important values like freedom of expression and transparency are -- the exact values that Xu has long advocated," Yaqiu Wang, China researcher at Human Rights Watch, told news agency.

But the disappearance of Xu illustrates how the Chinese state "persists in its old ways" by "silencing its critics", she said.

Xu -- who founded a movement calling for greater transparency among high-ranking officials -- previously served a four-year prison sentence from 2013 to 2017 for organising an "illegal gathering".

"That he was a fugitive for so many days while continuing to speak out, that in itself was... a kind of challenge to (Chinese authorities)," said Hua Ze, a long-time friend of Xu who told AFP she lost contact with the Chinese activist on Saturday morning.