Donald Trump was reportedly taken to underground bunker during White House protests

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.

Saint Martin's Island, Feb 12: At least 15 women and children drowned and more than 50 others were missing after a boat overloaded with Rohingya refugees sank off southern Bangladesh as it tried to reach Malaysia Tuesday, officials said.

Some 138 people -- mainly women and children -- were packed on a trawler barely 13 metres (40 feet) long, trying to cross the Bay of Bengal, a coast guard spokesman told news agency.

"It sank because of overloading. The boat was meant to carry maximum 50 people. The boat was also loaded with some cargo," another coast guard spokesman, Hamidul Islam, added.

Nearly one million Rohingya live in squalid camps near Bangladesh's border with Myanmar, many fleeing the neighbouring country after a 2017 brutal military crackdown.

With few opportunities for jobs and education in the camps, thousands have tried to reach other countries like Malaysia and Thailand by attempting the hazardous 2,000-kilometre journey.

In the latest incident, 71 people have been rescued including 46 women. Among the dead, 11 were women and the rest children.

Anwara Begum said two of her sons, aged six and seven, drowned in the tragedy.

"We were four of us in the boat... Another child (son, aged 10) is very sick," the 40-year-old told news agency.

Fishermen tipped off the coast guard after they saw survivors swimming and crying for help in the sea.

The boat's keel hit undersea coral in shallow water off Saint Martin's Island, Bangladesh's southernmost territory, before it sank, survivors said.

"We swam in the sea before boats came and rescued us," said survivor Mohammad Hossain, 20.

Coast guard commander Sohel Rana said three survivors, including a Bangladeshi, were detained over human trafficking allegations.

An estimated 25,000 Rohingya left Bangladesh and Myanmar on boats in 2015 trying to get to Thailand, Malaysia and Indonesia. Hundreds drowned when overloaded boats sank.

Begum said her family paid a Bangladeshi trafficker $450 per head to be taken to Malaysia.

"We're first taken to a hill where we stayed for five days. Then they used three small trawlers to take us to a large trawler, which sank," she said.

Shakirul Islam, a migration expert whose group works with Rohingya to raise awareness against trafficking, said desperation in the camps was making refugees want to leave.

"It was a tragedy waiting to happen," he said.

"They just want to get out, and fall victim to traffickers who are very active in the camps."

Islam said in the past two months dozens of Rohingya reported approaches from traffickers to his OKUP migration rights group.

"Human smuggling and trafficking in the Bay of Bengal is particularly difficult to address as it requires concerted effort from multiple states," the Bangladesh head of UN agency the International Organization for Migration, Giorgi Gigauri, told news agency.

"The gaps in coordination are easily exploited by criminal networks."

Since last year, Bangladeshi authorities have picked up over 500 Rohingya from rickety fishing trawlers or coastal villages as they waited to board boats.

Trafficking often increases during the November-March period when the sea is safest for the small trawlers used by traffickers.

Bangladesh and Myanmar signed a repatriation deal to send back some Rohingya to their homeland, but none have agreed to return because of safety fears.

The charity Save the Children called on Myanmar to "take all necessary steps to ensure the Rohingya community can return to their homes in a safe and dignified manner".

"The tragic drowning of women and children... should be a wake-up call for us all," the group's Athena Rayburn said in a statement.

London, Apr 12: British Prime Minister Boris Johnson has thanked the medics and staff of the state-funded National Health Service (NHS) for saving his life after he tested positive for the coronavirus, saying he owed them his life.

In his first public statement since being moved out of the intensive care at St. Thomas’ Hospital in London on Saturday, the 55-year-old Johnson said, “I can't thank them enough, I owe them my life.”

Downing Street has said that Johnson, who completes a week in hospital on Sunday after being shifted there with persistent COVID-19 symptoms, continues to make “very good progress” while on the ward.

Coronavirus India update: State-wise total number of confirmed cases, deaths on April 12

He has been able to take short walks as his doctors monitor his recovery after being moved out of the intensive care and has been watching films and doing puzzles in his hospital bed.

Johnson's fiancee Carrie Symonds, who is pregnant with their first child, is said to have sent him letters and baby scans to lift his spirits during his time in the hospital.

Thousands of get-well-soon cards have also poured in for the prime minister since he went into self-isolation after testing positive for coronavirus over two weeks ago.

Asked about plans for his return to work, UK Home Secretary Priti Patel said on Saturday that the UK PM needed "time and space to rest, recuperate and recover".

The Indian-origin Cabinet minister, who led the daily Downing Street update on the pandemic on Saturday, revealed that the UK had recorded 917 new coronavirus deaths, taking the total deaths in the country to 9,875.

According to the Johns Hopkins University data, the country has nearly 80,000 coronavirus cases.

Patel urged people to stay at home over the Easter weekend to curb the spread of the virus, despite warm and sunny weather across parts of the UK.

“We have given the police powers to enforce the necessary measures we have put in place, including through enforcement fines," said Patel.

"If you don't play your part... our selfless police will be unafraid to act. You will be endangering the lives of your own family, friends and loved ones," she said.

Meanwhile, an Easter message posted on the official 10 Downing Street Twitter account on behalf of the prime minister also urged people to stay at home to save lives.

It read: “Wishing everyone a very happy Easter from Downing Street.

“This year across the country churches will remain closed, and families will spend the day apart. But by staying home, remember, you are protecting the NHS and saving lives.”