IMF calls for 'urgent' action by India amid slowdown

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, Jan 15: The Delhi government Wednesday told the high court that execution of the death row convicts in the Nirbhaya gangrape and murder case will not take place on January 22 as a mercy plea has been filed by one of them.

The four convicts -- Vinay Sharma (26), Mukesh Kumar (32), Akshay Kumar Singh (31) and Pawan Gupta (25) -- are to be hanged on January 22 at 7 am in Tihar jail. A Delhi court had issued their death warrants on January 7.

Justices Manmohan and Sangita Dhingra Sehgal were told by the Delhi government and the Centre that the petition filed by convict Mukesh, challenging his death warrant, was premature.

The Delhi government and the prison authorities informed the court that under the rules, it will have to wait for the mercy plea to be decided before executing the death warrant.

They also said that none of the four convicts can be executed on January 22 unless the present mercy plea is decided.

The Supreme Court had on Tuesday dismissed the curative pleas of Mukesh and Vinay.

The mercy plea hearing began Wednesday morning and will continue in the afternoon.

New Delhi, Jan 31: Nirbhaya's mother Asha Devi on Friday said she will continue her fight till the convicts in the 2012 gangrape and murder case are hanged, shortly after a Delhi court postponed the execution of death warrants till further order.

Devi told reporters her "hopes are dashed" but she will continue her fight.

"These convicts have no right to live. We keep getting disappointed by the system. I will continue my fight till the convicts are hanged," she said.

A Delhi court postponed the execution of death warrants of the four convicts in the Nirbhaya gangrape and murder case till further order.

Additional sessions judge Dharmender Rana passed the order on a plea by the convicts seeking a stay on their execution on Saturday, February 1.

Devi said because of the loopholes in law the "criminals' lawyers had the audacity to challenge me in court that they will not be hanged".

The black warrants for execution of the death sentence against Pawan Gupta, Vinay Kumar Sharma, Akshay Kumar and Mukesh Kumar Singh, were issued on January 17.

A 23-year-old physiotherapy intern who came to be known as "Nirbhaya" (the fearless one) was gangraped and savagely assaulted on the night of December 16, 2012, in a moving bus in South Delhi. She died of her injuries a fortnight later in a Singapore hospital.