Nepal: 23 killed after college bus falls into gorge

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.

Mumbai, May 7: Maharashtra Minister Nawab Malik on Wednesday accused the BJP-led Uttar Pradesh and Karnataka governments of adopting an uncooperative approach in taking back migrant workers hailing from these two states.

Mr Malik said that such a problem has not arisen with other states like Bihar, Rajasthan and another BJP-ruled state, Madhya Pradesh.

"They are creating new hurdles. There are no such problems in case of other states like Bihar, Rajasthan, Madhya Pradesh and West Bengal though.

"The process (of sending back migrants) has been smooth in the case of these states," Mr Malik said.

The NCP leader alleged that the Uttar Pradesh and Karnataka governments either don't want the people hailing from their states to return or are deliberately creating hurdles so that out of job workers do not go back in big numbers.

The Uttar Pradesh and Karnataka government should understand that the migrant workers are not ready mentally to stay back in Maharashtra and want to return to their native states, Mr Malik said.

The NCP minister said the Maharashtra government has been sending the applications received from migrant workers to the nodal officers of their respective native districts.

Once the nodal officers (of the native districts) concerned approve the applications, the workers are sent back either by trains or private vehicles following their medical tests, Mr Malik added.

LGeneva, Jun 27:: The number of confirmed coronavirus cases worldwide has risen by over 177,000 in the past 24 hours to 9.4 million and the death toll has topped 480,000, the World Health Organisation (WHO) said on Friday (local time).

On Thursday, the WHO reported 167,056 new cases and 5,336 related deaths.

The fresh daily situation report estimates the number of infections confirmed in the past 24 hours at 177,012. Further, 5,116 virus-related deaths were reported over the same period, taking the toll to 484,249.

The Americas lead the count with over 4.7 million cases, followed by Europe with more than 2.6 million.