Narendra Modi becomes first sitting PM to visit Dharmasthala

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, Apr 28: There are a total of 523 COVID-19 positive cases have been confirmed in the state, Department of Health and Family Welfare of Karnataka informed on Tuesday.
It informed that there are 295 active COVID-19 cases in Karnataka presently, while 207 patients have been discharged, 20 deaths have been reported.

According to a district-wise breakup, a maximum of 131 cases were reported from Bengaluru urban, followed by Mysuru with 87 cases and Belagavi with 52 cases.

India's total number of coronavirus positive cases rises to 29,974 (including 22010 active cases, 7027 cured/discharged/migrated and 937 deaths), Ministry of Health and Family Welfare said on Tuesday.

Tumakuru, Jan 4: Three people were burnt alive and four others sustained injuries in a head-on collision between a four-wheeler (Omni van) and a private bus on NH-206 near Doddaguni in Gubbi taluk of Tumakuru district in the early hours of Saturday.

Police said that Narasamma’s relatives and villagers were taking her to a hospital in Nittur when a private bus, heading to Shivamogga from Bengaluru, collided with the van on the tank bund road near Doddguni around 0200 hrs. The two vehicles caught fire and Vasanthkumar, Ramaiah and Narasamma were burnt alive in the van. The passengers in the private bus escaped unhurt.

The deceased were identified as Vasanthkumar (23), Ramaiah (62) and Narsamma (60) of N Hosahalli in Gubbi taluk, whereas the injured were identified as Ravikumar (23), Radhamani (30), Narasimha Murthy (40) and Gowramma (28).