Uncertainty looms large over end to US crisis

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.

May 20: The novel coronavirus is behaving differently in patients in northeast China who have contracted it recently compared with early cases, indicating it is changing as it spreads, a prominent doctor said.

China, which has largely brought the virus under control, has found new clusters of infections in the northeastern border provinces of Jilin and Heilongjiang in recent weeks, raising concern about a second wave.

Qiu Haibo, an expert in critical care medicine who is part of a National Health Commission expert group, said the incubation period of the virus in patients in the northeast was longer than that of patients in Wuhan, the central city, where the virus emerged late last year.

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"This causes a problem, as they don't have any symptoms. So when they gather with their families they don't care about this issue and we see family cluster infections," Qiu told state broadcaster CCTV in a programme broadcast late on Tuesday.

Patients in the northeastern clusters were also carrying the virus for longer than earlier cases in Wuhan, and they were taking longer to recover, as defined by a negative nucleic acid test, he said.

Patients in the northeast also rarely exhibited fever and tended to suffer damage to the lungs rather than across multiple organs, he said.

He said the virus found in the northeastern clusters was probably imported from abroad, which could account for the differences.

He did not say where he though they might have come from but both Jilin and Heilongjiang border Russia.

China reported five new coronavirus cases on Wednesday, down from six a day earlier.

Four of the new cases were local transmissions and one was imported by a traveller coming from abroad, the commission said in a statement, compared with three imported cases reported the previous day.

China's total number of coronavirus infections stands at 82,965, while the death toll 4,634. 

Houston, Jun 10: George Floyd was fondly remembered Tuesday as “Big Floyd” — a father and brother, athlete and neighborhood mentor, and now a catalyst for change — at a funeral for the black man whose death has sparked a global reckoning over police brutality and racial prejudice.

More than 500 mourners wearing masks against the coronavirus packed a Houston church a little more than two weeks after Floyd was pinned to the pavement by a white Minneapolis police officer who put a knee on his neck for what prosecutors said was 8 minutes and 46 seconds.

Cellphone video of the encounter, including Floyd’s pleas of “I can’t breathe,” ignited protests and scattered violence across the U.S. and around the world, turning the 46-year-old Floyd — a man who in life was little known beyond the public housing project where he was raised in Houston’s Third Ward — into a worldwide symbol of injustice.

“Third Ward, Cuney Homes, that’s where he was born at,” Floyd’s brother, Rodney, told mourners at the Fountain of Praise church. “But everybody is going to remember him around the world. He is going to change the world.”

The funeral capped six days of mourning for Floyd in three cities: Raeford, North Carolina, near where he was born; Houston, where he grew up; and Minneapolis, where he died. The memorials have drawn the families of other black victims whose names have become familiar in the debate over race and justice — among them, Eric Garner, Michael Brown, Ahmaud Arbery and Trayvon Martin.

After the service, Floyd’s golden casket was taken by hearse to the cemetery in the Houston suburb of Pearland to be entombed next to his mother, for whom he cried out as he lay dying. A mile from the graveyard, the casket was transferred to a glass-sided carriage drawn by a pair of white horses. A brass band played as his casket was taken inside the mausoleum.

Hundreds of people, some chanting, “Say his name, George Floyd,” gathered along the procession route and outside the cemetery entrance in the mid-90s heat.

“I don’t want to see any black man, any man, but most definitely not a black man sitting on the ground in the hands of bad police,” said Marcus Brooks, 47, who set up a tent with other graduates of Jack Yates High School, Floyd’s alma mater.

In the past two weeks, amid the furor over Floyd’s death, sweeping and previously unthinkable things have taken place: Confederate statues have been toppled, and many cities are debating overhauling, dismantling or cutting funding for police departments. Authorities in some places have barred police from using chokeholds or are otherwise rethinking policies on the use of force.

Dozens of Floyd’s family members, most dressed in white, took part in the four-hour service. Grammy-winning singer Ne-Yo was among those who sang.

The mourners included actors Jamie Foxx and Channing Tatum, J.J. Watt of the NFL’s Houston Texans, rapper Trae tha Truth, Rep. Sheila Jackson Lee, Houston Police Chief Art Acevedo and Houston Mayor Sylvester Turner, who brought the crowd to its feet when he announced he will sign an executive order banning chokeholds in the city.

“I know you have a lot of questions that no child should have to ask, questions that too many black children have had to ask for generations: Why? Why is Daddy gone?” former Vice President Joe Biden, the Democratic presidential candidate, said, addressing Floyd’s 6-year-old daughter in a video eulogy played at the service. “Now is the time for racial justice. That’s the answer we must give to our children when they ask why.”

Biden made no mention of his opponent in November. But other speakers took swipes at President Donald Trump, who has ignored demands to address racial bias and has called on authorities to crack down hard on lawlessness.

“The president talks about bringing in the military, but he did not say one word about 8 minutes and 46 seconds of police murder of George Floyd,” said the Rev. Al Sharpton, the civil rights activist. “He challenged China on human rights. But what about the human right of George Floyd?”

Most of the pews were full, with relatively little space between people.

“So much for social distancing today,” the Rev. Remus Wright told mourners, gently but firmly instructing those attending to wear face masks.

Texas has no limit on how many people can gather in places of worship during the pandemic, though Republican Gov. Greg Abbott has encouraged churches to follow federal health guidelines.

Although the church service was private, at least 50 people gathered outside to pay their respects.

“There’s a real big change going on, and everybody, especially black, right now should be a part of that,” said Kersey Biagase, who traveled more than three hours from Port Barre, Louisiana, with his girlfriend, Brandy Pickney. They wore T-shirts printed with Floyd’s name and “I Can’t Breathe.”

Floyd served nearly five years in prison for robbery with a deadly weapon before becoming a mentor and a church outreach volunteer in Houston. He moved to Minnesota several years ago through a program that tried to change men’s lives by helping them find work in new settings.

At the time of his death, Floyd was out of work as a bouncer at a Minneapolis club that had closed because of the coronavirus outbreak. He was seized by police after being accused of passing a counterfeit $20 bill at a convenience store.

Four Minneapolis officers were arrested in his death: Derek Chauvin, 44, was charged with second-degree murder. J. Alexander Kueng, Thomas Lane and Tou Thao were charged with aiding and abetting. All four could get up to 40 years in prison.

Some of the mostly peaceful demonstrations that erupted after Floyd’s death were marked by bursts of arson, assaults, vandalism and smash-and-grab raids on businesses, with more than 10,000 people arrested. But protests in recent days have been overwhelmingly peaceful.