Security, welfare of people are govt's priority: Amit Shah

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.

Ujjain, Jul 9: Kanpur encounter main accused Vikas Dubey has been arrested at a police station here on Thursday, as per sources in the Uttar Pradesh government.

"Vikas Dubey, the main accused in Kanpur encounter case, has been arrested at a police station in Ujjain," said UP government sources.

Dubey is the main accused in the encounter that took place in Kanpur last week, in which a group of assailants allegedly opened fire on a police team, which had gone to arrest him.

Eight police personnel were killed in the encounter.

Earlier today, Bahua Dubey and Prabhat Mishra, close aides of the main accused, were killed in separate encounters in Etawah and Kanpur respectively.

Whereas, Shyamu Bajpai, also an aide to Dubey, has been arrested by Chaubeypur police following an encounter. He carried a reward of Rs 25,000. Uttar Pradesh's Special Task Force (STF) had gunned down Vikas Dubey's close aide Amar Dubey in Hamirpur district, earlier on Wednesday.

New Delhi, Mar 23: The total number of COVID-19 cases in the country rose to 390 on Monday after 30 fresh cases were reported.

The figure includes 41 foreign nationals and the seven deaths reported so far.

Gujarat, Bihar and Maharahstra reported a death each on Sunday, while four fatalities were reported earlier from Karnataka, Delhi, Maharashtra and Punjab, the Union Health Ministry said.

The total number of active COVID-19 cases across the country now stands at 359, while 24 people have been cured/discharged/migrated.