Quake sows panic in Papua New Guinea, tsunami threat passes

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.

The coronavirus pandemic has sickened more than 2,425,000 people, according to official counts. So far at least 164,000 people have died, and the virus has been detected in at least 177 countries, as the following table shows.

Washington, Feb 18: The upcoming visit of President Donald Trump to India later this month has the potential to usher in a new era of bilateral ties between the two countries, a top American business advocacy group has said.

President Trump will pay a state visit to India on February 24 and 25 at the invitation of Prime Minister Narendra Modi. He would be accompanied by First Lady Melania Trump.

This would be the president's first bilateral visit in the third decade of the 21st century and also the first after his acquittal by the Senate in the impeachment trial.

"I believe President Trump's upcoming visit to India has the potential to usher in a new era of our bilateral ties," Mukesh Aghi, President of the US India Strategic and Partnership Forum (USISPF) said in a statement on Monday.

On the sidelines of the visit, the USISPF, in collaboration with the Federation of Indian Chambers of Commerce and Industry (FICCI) and the ORF, has announced to organise a program entitled "US-India Forum: Partners for Growth".

The full-day discussion will focus on the key pillars defining India and the US' strategic, economic, and cultural partnership over the next decade.

"We have an opportunity before us to make real progress on multiple aspects of the relationship— whether it is upholding peace and security in the Indo-Pacific region; building upon an already strong energy partnership; developing co-production and co-development opportunities in the defense space; or strengthening bilateral trade," Aghi said.

"We look forward to an extremely successful visit and some concrete outcomes from the visit," he said.

The day-long programme on February 25 in New Delhi, will bring together over 500 senior business executives, members of the US-India think tank community and leading figures of the Indian diaspora to set the agenda for this strategic partnership.

Discussions during the day will touch upon areas, including the Indo-Pacific Strategy and Maritime Security; the US-India Defence Partnership, the US-India Energy Partnership, Elevating US-India Trade and Investment and Role of the Indian Diaspora in US-India Relations.