Mani Shankar Aiyar calls Modi ‘neech’; suspended from Congress

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.

Tezpur (Assam), Mar 2: Seven boys, who had appeared for their class 10 board examinations, were apprehended on Sunday for allegedly raping and killing a 12-year-old girl in Assam's Biswanath district, police said.

The girl was hanged from a tree after the crime.

The incident happened on Friday in Chakla village under the jurisdiction of Gohpur police station, they said.

A senior police officer told PTI that the culprits, all of them High School Leaving Certificate (HSLC) examinees, were on the run, but were nabbed by a police team.

The accused after the examination had called the victim to a house on the pretext of organising a party and raped her, the officer said.

It is suspected that the girl was raped on Friday night and then hanged from a tree in a forest near the house, the senior police officer said.

The body was found on Saturday.

New Delhi, Jan 1: Newly-appointed Chief of the Defence Staff General Bipin Rawat on Wednesday said the armed forces stay away from politics and work as per the directives of the government of the day, remarks that come amid allegations that the forces were being politicised.

Gen Rawat also said that his focus as CDS will be to integrate the efforts of the three services and to work as a team.

"We keep ourselves away from politics. We act according to the directives of the government of the day," he said.

Gen Rawat said his focus will be to ensure best and optimal use of resources allocated to the three services.