China issues US travel warning, citing crime: State media

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 12: The US has overtaken Italy as the country with the highest number of deaths due to COVID-19 pandemic with the fatalities crossing 20,000, according to Johns Hopkins University data, as the novel coronavirus continues to wreak havoc across the globe.

The deadly coronavirus, that originated in China in December last year, has so far killed more than one lakh people across the globe. The United States on Saturday became the country with the highest number of deaths at 20,597, surpassing Italy's 19,468 fatalities.

More than 5.3 lakh Americans have tested positive for coronavirus, which is about the same for the next four countries put together: Spain (163,027), Italy (152,271), Germany (125,452) and France (93,790). In terms of fatalities, the US and Italy are followed by Spain (16,606), France (13832) and United Kingdom (9,875), the varsity data showed.

New York City, the financial capital of the world, has emerged as the epicenter of coronavirus in the world. A city of 8.3 million, which is one of the most densely populated cities in the US, by Saturday night had as many as 8,627 deaths and more than 180,000 people had tested positive for COVID-19.

President Donald Trump has declared a national emergency and all the 50 States have been notified with major disaster declaration. More than 95 per cent of the country's 330 million population are under stay-at-home order. Trump has deployed more than 50,000 personnel from the armed forces in fight against COVID-19.

After an initial two-week social mitigation measures, that includes social distancing, the measures have been extended till April 30. Initially, members of the White House Task Force on Coronavirus had projected between one and two lakhs deaths. Now, they have dropped the projection to 60,000 deaths, mainly due to the successful implementation of these measures.

"The people of our country have gone through a lot. But we did it the right way. And we look like we'll be coming in on the very, very low side, really below the lowest, the lowest side of the curve of death," Trump told Fox News on Saturday night.

Trump asserted that situation was improving in places like New York, where there is a drop in new patients. Responding to a question, he said he wanted the country to open up as soon as possible.

However, he has not taken a decision so far, even as some media reports said that he the President was looking for early May.

"I think it's going to be the toughest decision that I've ever made. I really, hopefully that I ever will have to make. But it's certainly the toughest decision that I've ever made. I hope that I'm going to make the right decision," Trump said, adding that he will be making a decision reasonably soon.

"We're setting up a council now of some of the most distinguished leaders in virtually every field including politics and business and medical. We'll be making that decision fairly soon," Trump said.

Meanwhile, The New York Times reported that its investigations have revealed that the president was warned about a potential pandemic but that internal divisions, lack of planning and his faith in his own instincts led to a halting response.

According to The Washington Post, coronavirus is killing about one in 10 hospitalised middle-aged patients and four in 10 older than 85 in the United States. It is particularly lethal to men even when taking into account common chronic diseases that exacerbate risk.

Globally, the novel coronavirus has killed 108,862 people and infected over 1.7 million people globally. The US has the highest number of infections at 529,887, according to Johns Hopkins University data.

Tehran, Mar 15: Two hundred and thirty-four Indians stranded in coronavirus-hit Iran have arrived in India, External Affairs Minister S Jaishankar said on Sunday.

The batch comprises 131 students and 103 pilgrims, he said.

“234 Indians stranded in Iran have arrived in India; including 131 students and 103 pilgrims. Thank you Ambassador Dhamu Gaddam and @India_in_Iran team for your efforts. Thank Iranian authorities,” Jaishankar tweeted.

The third batch of Indians from Iran arrived early Sunday. A second batch of 44 Indian pilgrims had arrived from Iran on Friday.

Iran is one of the worst-affected countries by the coronavirus outbreak and the government has been working on plans to bring back Indians stranded there.

The first batch of 58 Indian pilgrims were brought back from Iran on Tuesday.