Hindu priest attacked by ‘nationalist’ near temple in US

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, Mar 20: The four men convicted of the gang rape and murder of a Delhi woman on December 16, 2012 were hanged in the darkness of pre-dawn on Friday, ending a horrific chapter in India's long history of sexual assault that had seared the nation's soul. Mukesh Singh (32), Pawan Gupta (25), Vinay Sharma (26) and Akshay Kumar Singh (31) were executed at 5.30 am for the savage assault in an empty moving bus on the 23-year-old physiotherapy intern who came to be known the world over as Nirbhaya, the fearless one.

This is the first time that four men have been hanged together in Tihar Jail, South Asia's largest prison complex that houses more than 16,000 inmates. The executions were carried out after the men exhausted every possible legal avenue to escape the gallows. Their desperate attempts only postponed the inevitable by less than two months after the first date of execution was set for January 22.

They were hanged at 5.30 am, Director General of Prison Sandeep Goel said.

After raping and brutalising the woman, the men, one of whom was a juvenile at the time, dumped her on the road and left for dead on the cold winter night. Her friend who was with her was also severely beaten and thrown out along with her. She was so severely violated that her insides were spilling out when she was taken to hospital. She died in a Singapore hospital after battling for her life for a fortnight.

Six people, including the four convicts and the juvenile, were named as accused.

While Ram Singh allegedly committed suicide in the Tihar Jail days after the trial began in the case, the juvenile was released in 2015 after spending three years in a correctional home.

The road to the gallows was a long and circuitous one, going through the lower courts, the High Court, the Supreme Court and the president's office before going back to the Supreme Court that heard and rejected various curative petitions.

The death warrants were deferred by a court thrice on the grounds that the convicts had not exhausted all their legal remedies and that the mercy petition of one or the other was before the president.

On March 5, a trial court issued fresh death warrants for March 20 at 5.30 am as the final date for the execution.