13-yr-old girl's hijab ripped off, called 'terrorist' in US

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.

Mar 13: Canadian Prime Minister Justin Trudeau and his wife announced they were self-isolating Thursday as she undergoes tests for the new coronavirus after returning from a speaking engagement with "mild flu-like symptoms."

Sophie Gregoire-Trudeau's symptoms have subsided since she recently got back from Britain, but as a precaution the prime minister "will spend the day in briefings, phone calls and virtual meetings from home," according to a statement.

Trudeau also cancelled a meeting Thursday and Friday with Canada's provincial and territorial leaders in Ottawa, but still planned to speak with them and world leaders by phone about measures being taken to curb the spread of the virus in Canada.

Gregoire-Trudeau's symptoms had included "a low fever late last night." She immediately sought medical advice and testing.

Trudeau has exhibited no symptoms, and was advised by doctors "to continue daily activities while self-monitoring."

"However, out of an abundance of caution, the prime minister is opting to self-isolate and work from home until receiving Sophie's results," said his office.

Since the novel coronavirus first emerged in late December 2019, 127,070 cases have been recorded in 115 countries and territories, killing 4,687 people, according to an AFP tally compiled at 1200 GMT on Thursday based on official sources.

Canada has so far reported more than 100 cases in six provinces, and one death.

Also Thursday, the Canada's Juno music awards cancelled its upcoming gala show, planned for Sunday evening in Saskatoon, Saskatchewan.

"We are devastated to cancel this national celebration of music, but at this time of global uncertainty, the health, safety and well-being of all Canadians must stand at the forefront of any decisions that impact our communities," organisers said in a statement.

And in Quebec province, Premier Francois Legault unveiled a series of measures to prevent the spread of the coronavirus, including placing all travellers returning from overseas under quarantine for two weeks.

Quebec also banned indoor gatherings of more than 250 people.

Paris, Jun 29: More than half a million people have been killed by the novel coronavirus, nearly two thirds of them in the United States and Europe, according to an news agency tally at 2200 GMT Sunday based on official sources.

The official death count for the disease now stands at 500,390 deaths from 10,099,576 cases recorded worldwide. The United States has suffered the highest death count (125,747), followed by Brazil (57,622) and the United Kingdom (43,550).

The tallies, using data collected by AFP from national authorities and information from the World Health Organization (WHO), probably reflect only a fraction of the actual number of infections.

Many countries are testing only the most serious cases.