The Women in White, Seated Together At Trump's State of the Union Address

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.

The new visa regulations requiring international students in the US with an F-1 visa to take at least one in-person course or face the prospect of deportation is likely to "cause uncertainties and difficulties" for some students, the Indian Embassy has said.

"These new modifications at a time when many of the US universities and colleges are yet to announce their plans for the new academic year are likely to cause uncertainties and difficulties for some Indian students wishing to pursue their studies in the US," said a spokesperson of the Indian Embassy.

Responding to media queries, the spokesperson said the Indian government has taken up the matter with concerned US officials.

At the India US Foreign Office Consultations held on July 7, Foreign Secretary Harsh Vardhan Shringla conveyed India's concerns on the matter to Under Secretary of State for Political Affairs David Hale.

According to a recent report of Student and Exchange Visitor Program (SEVP), there were 1,94,556 Indian students enrolled in various academic institutions of the US in January this year. Of these 1,26,132 were males and 68,405 were females.

Noting that partnership in higher education is a key component of the strong people-to-people ties between India and the US, the spokesperson said in the last two decades Indian students in American universities and colleges have been the harbingers of a strong partnership between technology and innovation sectors between the two countries.

The spokesperson hoped that the US authorities would provide adequate flexibility in their visa rule, keeping in mind the extraordinary circumstances created by the COVID-19 pandemic for the Indian students community.

We continue to engage all the stakeholders in the matters, including the US administration officials, Congressional leaders, universities and colleges as well as the Indian students community in the US as we move forward towards the 2020-21 academic year to further strengthen our bilateral partnership in higher education, the spokesperson said.

Announced by the SEVP on July 6, the new rules provide temporary exemptions for nonimmigrant students on F-1 and M-1 visas taking online classes due to the COVID-19 pandemic for the fall semester of the 2020 academic year.

While these modifications do provide some flexibility for US universities and colleges to adopt a hybrid model -- that is a mixture of online and in person classes -- they also restrict international students on F-1 and M-1 visas from taking courses entirely online, the spokesperson said.

London, Jun 4: Meghan, Britain's Duchess of Sussex, has spoken about events following the death of George Floyd saying she was sorry that children had to grow up in a world where racism still existed and that current events in the United States were "devastating".

"I know you know that black lives matter," Meghan said in a video she recorded for students graduating from her old high school in Los Angeles which was aired on Wednesday.

The death of Floyd has become the latest flashpoint for long-simmering rage over police brutality against African Americans and led to nationwide protests, some violent, with curfews imposed in some cities to quell the disorder.

"For the past couple of weeks I've been planning on saying a few words to you for your graduation and as we've all seen over the last week what is happening in our country, and in our state and in our home town of LA is absolutely devastating," said Meghan, whose mother is African American and father is white.

"First thing I want to say to you is that I'm sorry, I'm so sorry that you have to grow up in a world where this is still present," she said in her message to the girls at the Immaculate Heart High School.

The duchess, a former US actress and wife of Queen Elizabeth's grandson Prince Harry, said she wanted to say "the right thing" and was nervous her words would be "picked apart".

"The only wrong thing to say is to say nothing. Because George Floyd's life mattered, and Breonna Taylor's life mattered, and Philando Castile's life mattered and Tamir Rice's life mattered and so did so many other people whose names we know, and whose names we do not know," she said.

Britain's royal family by tradition does not comment on political issues. However, Meghan and Harry stepped down from their official royal roles at the end of March and are now living in Los Angeles with their baby son Archie.

In her message, the 38-year-old reflected on her own memories of the 1992 LA riots.

"Those memories don't go away and I can't imagine that at 17 or 18 years old, which is how old you are now, that you would have to have a different version of that same type of experience," she said.

"That's something you should have an understanding of, but an understanding of as a history lesson not as your reality. So I'm sorry that in a way we have not gotten the world to the place you deserve it to be."