Violence cannot solve any problem: PM 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, Feb 19: Delhi Chief Minister Arvind Kejriwal met Union Home Minister Amit Shah on Wednesday, their first meeting after the assembly polls in the national capital.

The meeting went on for over 20 minutes at Shah's residence. The meeting was earlier scheduled at the Home Ministry.

"Met Hon'ble Home Minister Sh Amit Shah ji. Had a very good and fruitful meeting. Discussed several issues related to Delhi. Both of us agreed that we will work together for development of Delhi," Kejriwal tweeted.

Shah had led the BJP offensive against Kejriwal in the Delhi Assembly polls in which AAP trounced the saffron party, bagging 62 of the 70 seats.

Mumbai, Jan 30: The Uttar Pradesh Special Task Force (STF) has arrested Dr Kafeel Khan from Mumbai airport for allegedly making inflammatory statements at AMU during protests against the Citizenship Amendments Act (CAA) last month, officials said.

Khan was arrested on Wednesday night with assistance from Mumbai Police at the airport when he arrived in the city to attend anti-CAA protests, an official said.

"Officials of the UP STF arrested Dr Kafeel Khan in a case which was registered at Civil Lines Police Station under section 153 A (promoting enmity between different groups) of IPC. Our police team helped our UP counterparts on their request," said an official from Mumbai Police.

He claimed that Khan had made inflammatory statements on December 12 last year during the protest near Bab e Syed Gate outside the Aligarh Muslim University in front of more than 600 students.

The official also alleged that the Gorakhpur doctor had made objectionable comments against Union Home Minister Amit Shah.

The FIR against Khan mentions that Swaraj India's president Yogendra Yadav was also present during the speech at AMU.

Following the arrest in the case, Khan was taken to the Sahar Police Station and after completing formalities he will be taken to UP on transit remand, the official said.

Khan, a paediatrician, had come to the limelight in 2017 when a controversy broke out after the death of over 60 children in less than a week at the BRD Medical College in Gorakhpur, UP.