Indo-Canadians celebrate India Day

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.

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.

Washington, Jun 3: US President Donald Trump's administration on Tuesday announced investigations into foreign digital services taxes it says are aimed squarely at American tech firms.

Following a similar trade investigation against France last year, the US Trade Representative office now is looking into taxes in Britain and the European Union, as well as Indonesia, Turkey and India.

"President Trump is concerned that many of our trading partners are adopting tax schemes designed to unfairly target our companies," USTR Robert Lighthizer said in a statement.

"We are prepared to take all appropriate action to defend our businesses and workers against any such discrimination."

Washington opposes the efforts to tax revenues from online sales and advertising, saying they single out US tech giants like Google, Apple, Facebook, Amazon and Netflix.

The US and France have agreed to negotiate till the end of the year over a digital services tax Paris approved in 2019, after USTR found them to be discriminating and threatened retaliatory duties of up to 100 percent on French imports such as champagne and camembert cheese.

Trump has embroiled the US in numerous trade disputes since taking office in 2017, including a months-long trade war with China that cooled with the signing of a partial deal in January.