Pak rakes up Kashmir issue at UN, India calls it 'lonely voice from wilderness'

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, Apr 20: The US wants to send a team of experts to China to investigate coronavirus, President Donald Trump has said, a day after he warned Beijing of "consequences" if it was knowingly responsible for the spread of COVID-19 which has killed more than 165,000 people globally, including over 41,000 in America.

Describing the coronavirus as a plague, Trump, during his White House news conference on Sunday, said that he is not happy with China where the pandemic emerged in December last year in the central Chinese city of Wuhan.

“We spoke to them (Chinese) a long time ago about going in. We want to go in. We want to see what's going on. And we weren't exactly invited, I can tell you that,” the President told reporters.

“I was very happy with the (trade) deal (with China), very happy with everything and then we found out about the plague and since we found out about that I'm not happy,” he said.

The US has launched an investigation into whether the deadly virus "escaped" from the Wuhan Institute of Virology.

He has repeatedly expressed disappointment over China's handling of the coronavirus disease, alleged non-transparency and initial non-cooperation from Beijing with Washington on dealing with the crisis.

“Based on an investigation, we are going to find out,” Trump told reporters.

A day earlier, he warned China that it should face consequences if it was "knowingly responsible" for the spread of the novel coronavirus, upping the ante on Beijing over its handling of the COVID-19 pandemic.

“If they (China) were knowingly responsible… then there should be consequences. You're talking about, you know, potentially lives like nobody's seen since 1917,” Trump said on Saturday.

The opposition Democratic Party said that Trump has falsely claimed he acted early by restricting travel from China when it was little too late and he continued to downplay the virus throughout February.

The number of COVID-19 deaths in the US crossed 41,000 and the total infections were more than 764,000 so far.

New York, the epicentre of the deadly COVID-19 in the US, has 2,42,000 cases and over 17,600 fatalities so far. It has registered a 50-percent decline in new cases over an eight-day period.

The novel virus, which emerged in China in December last year, has killed over 160,000 and infected more than 2.3 million people worldwide.

China on Tuesday justified the killing of an army officer and two soldiers of India and accused Indian troops of crossing a disputed border between the two countries.

Foreign ministry spokesman Zhao Lijian said Indian troops crossed the border line twice on Monday, "provoking and attacking Chinese personnel, resulting in a serious physical confrontation between border forces on the two sides".

An Indian Army officer and two soldiers have been killed in a "violent face-off" with Chinese troops along the Line of Actual Control (LAC), disrupting the fragile peace talks.

"During the de-escalation process underway in the Galwan Valley, a violent face-off took place last night with casualties on both sides," the Indian Army said in a statement.