Saudi Arabia suspends entry for pilgrims over coronavirus

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.

New Delhi, Feb 5: Taking on Delhi Chief Minister Arvind Kejriwal after Shaheen Bagh shooter Kapil Baisala was identified as an AAP worker by police, BJP chief J P Nadda on Tuesday said it exposed the party and Kejriwal who were playing with the country's security.

The Aam Aadmi Party hit back, questioning the police investigation.

In a series of tweets, Nadda said people of the country and Delhi today have seen the "dirty face" of AAP.

"For political longing, Kejriwal and his people even sold the security of the country. Earlier, Kejriwal used to insult the Army and advocate terrorists, but today relations with those who carry out their terrorist activities came to light," he said.

Nadda said he wanted to make it clear to Kejriwal that this country is bigger than any election, any government, and "this nation will not forgive those who play with its security. Kejriwal and his entire team have been exposed. The people of Delhi will give a befitting reply".

He claimed the entire country has seen "photos of Imam Hussain, the MLA and former minister of the Delhi government, with a radical terrorist organisation, PFI".

Days before Delhi goes to polls, police claimed that Baisala is a member of the Aam Aadmi Party. They said Baisala joined the party in early 2019 along with his father.

Police said it had photos of Baisala purportedly joining AAP along with his father Gaje Singh last year.

AAP's Rajya Sabha MP Sanjay Singh alleged that photos which were part of investigation were leaked to the BJP. He also said the party will approach the Election Commission to raise this issue, which has cropped up four days before the polling date.

"On whose instance, the police is giving statement? How did the photos which were part of the investigation reach the BJP? Before the news came out, Manoj Tiwari in the morning stated that the accused was from AAP. How did Manoj Tiwari get this news," Singh questioned in a press conference.

Union minister and BJP's in-charge for the Delhi polls, Prakash Javadekar, in a press conference alleged that "their (AAP's) designs are very clear from the beginning and they are trying every trick".

The whole conspiracy of AAP is to "divide society, cause fear in a community and create a vote bank," he charged.

Javadekar also claimed that photos of Baisala were recovered by police from his mobile phone although they were erased.

He also claimed that Baisala and his father were welcomed by Sanjay Singh at their joining of AAP.

"This proves AAP misleads youth and pushes them on the wrong path. AAP's strategy is to divide two communities, they want to instigate riots in Delhi," Javadekar alleged.

He further alleged that AAP leader Sanjay Singh had said violence would take place in Delhi. Their "conspiracy has been exposed by Delhi Police," he claimed.

"We condemn this politics of AAP," he said.

Javadekar also claimed this was "not an isolated incident" as AAP member Amanatullah Khan made a "very provocative speech" and the party supported Shaheen Bagh and did not give permission for the prosecution of members of the "tukde-tukde gang".

He hinted the BJP could approach the Election Commission against AAP over the issue.

Washington, May 20: The United States recorded another 1,536 coronavirus deaths over the past 24 hours, the Johns Hopkins University tracker said.

That figure, tallied as of 8:30 pm (0030 GMT), raises to 91,845 the total number of COVID-19 deaths in the US.

The US tops the global rankings both for the highest death toll and the highest number of infections, with more than 1.5 million cases.