Senior BHU official quits; Congress demands apology from PM Narendra Modi

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 17: Deputy Chief Minister Manish Sisodia does not have any car on his name, according to information shared in the poll affidavit filed by him for Delhi elections.

In the affidavit, it is also shown that while his self-acquired immovable property remained roughly the same as in 2015. His wife's self-acquired immovable property is worth roughly about Rs 65 lakh, as per his latest affidavit.

In the papers submitted during the nomination for 2015 Delhi polls, the senior AAP leader had declared that he owned a Maruti Swift car of make 2013.

However, in his 2020 affidavit, he has mentioned "nil" in the column for motor vehicles and other means of transport.

In the affidavit submitted on Thursday, his moveable assets were declared worth Rs 4,74,888 for 2018-19, as against Rs 4,92,624 for 2013-14.

In 2015, Sisodia had informed in his affidavit that he had bought a property in Vasundhara, Ghaziabad, worth Rs 5.07 lakh in April 2001. The approximate current market value of self-acquired property in 2015 was Rs 12 lakh.

In his current affidavit, the AAP leader has mentioned the same property. However, the approximate current market value of self-acquired property in 2020 has increased to Rs 21 lakh.

In his affidavit for the 2015 polls, Sisodia had also said that his wife had purchased a property in March 2008 costing Rs 8.70 lakh. At that time, the approximate value of her self-acquired property was Rs 20 lakh.