Clouds do prevent radars from detecting accurately: Air Marshal Raghunath Nambiar

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.

Thrissur, May 9: Five people were arrested for allegedly conducting congregational prayers at a mosque here in violationofthe COVID-19 lockdown norms.

A case was registered against five people for conducting evening prayers on Friday, police said.

We received information that prayers were being conducted in the mosque, they said adding they were held at Eriyad Masjidul Bilal mosque here.

On Friday, four people, including the president of a local temple trust, were arrested for allegedly conducting a religious recitation in a temple here in violation of lockdown restrictions.

Though lockdown conditions have been eased in accordance with the Centre's guidelines, public gatherings, including functions, weddings, political events and religious gatherings were not allowed.

New Delhi, Feb 28: The months of March, April and May are "likely to be warmer than normal" over northwest, west, central and parts of south India, the India Meteorological Department said today in its summer forecast.

Above normal heat wave conditions are also likely in the core heat wave (HW) zone during the season (March-May), the weather department said.

The core heat wave zone covers the states of Punjab, Himachal Pradesh, Delhi, Uttarakhand, Haryana, Rajasthan, Uttar Pradesh Gujarat, Madhya Pradesh, Bihar, Chhattisgarh, Jharkhand, West Bengal, Odisha and Telangana and parts of Maharashtra and coastal Andhra Pradesh.