Image of crying toddler on US border wins World Press Photo Award

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 26: The United States reported more than 39,000 new coronavirus cases on Thursday, its highest-ever single-day count as the government relaxed restrictions and is downplaying the threat of the deadly virus.

According to the Washington Post, experts believe there is a troubling lack of consistent, unified messaging from President Donald Trump and Vice President Mike Pence. They have downplayed the danger and denigrated effective disease defences such as mask-wearing, testing, and social distancing.

Churches, beaches, and bars are filling up with people and so are hospital beds, the report said.

The counties home to Dallas, Phoenix, and Tampa all reported record-high averages on at least 15 straight days in June.

The hardest-hit states are California, Texas, Florida and those that thought they had the virus under control, like Utah and Oregon.

"I think the politicians are in denial," said Kami Kim, director of the Division of Infectious Disease and International Medicine at the University of South Florida.

The chief of the Division of Pediatric Infectious Diseases at the University of Utah Health, Andrew T. Pavia, is of the view that the push to reopen quickly even as cases climb sends a dangerous and inaccurate message.

"On the one hand, you get messages from politicians and the business community that we have to go, go, go and open up," he said. "On the other hand, you're seeing epidemiological indicators that we still have to be very careful."

"It's cognitive dissonance," he added.

The Trump administration has tried to downplay the rising number. Pence called concerns about another surge of infections "overblown," the product of media "fearmongering."

Some governors have followed the administration's lead, blaming rising caseloads on more testing.

Testifying before a congressional committee this week, Anthony S. Fauci, the nation's top infectious-diseases expert, said the new cases were "a disturbing surge" spurred by community transmission rather than testing.

"That's something I'm really quite concerned about," Fauci said. "A couple of days ago, there were 30,000 new infections. That's very disturbing to me."

Several states like Arizona, Arkansas, the Carolinas, Mississippi, Tennessee, Texas and Utah have recently reported new highs in the number of coronavirus patients hospitalized.

"We're seeing a 40 per cent increase in the last two weeks in hospitalizations," said Dallas County Judge Clay Jenkins (D), the jurisdiction's top elected official. "We're by far at our record numbers, and we're at record numbers in north Texas. Houston is at a record, the state is at a record." The Texas Medical Center in Houston, a massive medical complex, reported Thursday that 100 per cent of the beds in its intensive care unit are occupied.