Oh My Gau Mata! Modi govt withdraws ban on sale of cattle for slaughter

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.

Bengaluru, May 5: The Karnataka excise department booked a case against a wine shop owner in this tech city for allegedly selling more liquor than permitted under the law to a buyer on the first day of shops reopening for business after 40-day lockdown on Monday, an official said on Tuesday.

"We have booked a case against licensed shop owner S. Venkatesh for reportedly selling Indian made liquor (IML) and beer to a buyer on Monday more than he is permitted under the Karnataka Excise Act section 36," Bengaluru South Excise Deputy Commissioner A. Giri told media persons.

The alleged sale came to light when the unidentified customer posted in the social media a receipt showing he bought liquor worth Rs 52,841 from Vanilla Spirit Zone in the city''s south-eastern suburb on Monday afternoon.

"Preliminary investigation revealed that 17.4 litres of IML was sold against the permissible limit of 2.3 litres and 35.1 litres of beer against the legal limit of 18.2 litres," Giri said.

Venkatesh, however, told Giri that the buyer paid for the liquor bought by him and seven of his colleagues at the same time from the shop as they entered together.

"We are investigating to ascertain if Venkatesh violated the license conditions by paying for liquor bought by his friends with him at the same time," Giri added.