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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.

Allahabad, Mar 1: Shabista Khan, wife of suspended pediatrician Dr Kafeel Khan, fears that her husband's life is in danger.

In a letter written to the chief justice of the Allahabad High Court and senior government authorities, Shabista has sought security for her husband who is lodged in Mathura jail for allegedly delivering provocative speech during anti-CAA protest at Aligarh Muslim University.

"My husband is being mentally tortured in jail and is being subjected to inhuman behaviour," Shabista wrote in her letter to the chief justice of Allahabad High Court, additional chief secretary (home) and director general (jail), among others.

She said that she apprehended that an attempt could be made on her husband's life in jail and demanded adequate security for him.

She also demanded that her husband should be kept away from active criminals and lodged with common prisoners.

New Delhi, May 27: With 6,387 new coronavirus cases in the last 24 hours, India's count of COVID-19 rose to 1,51,767 on Wednesday, said the Union Ministry of Health and Family Welfare.

170 people have also died in the last 24 hours due to the infection.

Currently, there are 83,004 active cases while 64,425 COVID-19 positive patients have been cured/discharged and one has migrated. So far, a total of 4,337 deaths have taken place across the country.

Among all states, Maharashtra has the highest number of COVID-19 cases with 54,758. Tamil Nadu has 17,728 cases with Gujarat at 14,821 cases. The national capital has 14,465 reported cases of coronavirus.