Obama refuses to meet Zardari in Chicago

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 9: The defacement of Mahatma Gandhi's statue by unknown miscreants was a "disgrace", US President Donald Trump has said, days after it was vandalised with graffiti and spray painting during the nationwide protests against the custodial killing of African-American George Floyd.

The statue, which is across the road from the Indian Embassy, was vandalised on the intervening night of June 2 and 3, prompting the Indian embassy to register a complaint with the local law enforcement agencies.

The incident happened during the week of nationwide protests against the custodial killing of Floyd in Minneapolis on May 25.

"It was a disgrace," Trump made the brief comment at the White House on Monday when asked about the incident.

The Indian Embassy here has taken up the matter with the US Department of State for early investigation into the matter, as also with the Metropolitan Police and National Park Service.

It is working with the US Department of State, Metropolitan Police and National Park Service for expeditious restoration of the statue at the park.

The US president and First Lady Melania Trump, during their visit to India in February, had spent considerable time at the Gandhi Ashram in Ahmedabad. Prime Minister Narendra Modi had personally given them a tour of the historic place.

"The First Lady and I have just had a pleasure of visiting Mahatma Gandhi's Ashram, a few miles from here, where he launched the famous Salt March," Trump had said during his address at the Namaste Trump rally at the Motera Stadium in Ahmedabad on February 24. A day later, Trump and the first lady also laid a wreath at Raj Ghat in New Delhi.

Pictures of Trump and the first lady with Gandhi's spinning wheel during their visit to the Sabarmati Ashram in Ahmedabad are seen hanging on the walls of the White House.

Last week, top US lawmakers and the Trump Campaign condemned the vandalisation of the statue.

"Very disappointing," tweeted Kimberly Guilfoyle, advisor to Donald J Trump for President Inc. and National Chair of the Trump Victory Finance Committees.

North Carolina Senator Tom Tillis said, "It's disgraceful to see the defacing of the Gandhi statue" in Washington DC.

"Gandhi was a pioneer of peaceful protesting, demonstrating the great change it can bring. Rioting, looting and vandalising do not bring us together, he said.

Senator Marco Rubio said, "more evidence that violent radicals and run of the mill crazies have hijacked legitimate protests to create anarchy or for their own purposes."

Protests against the custodial killing of Floyd turned violent in the US and prestigious monuments were damaged. In Washington DC, protestors burnt a historic church and damaged monuments like the Lincoln Memorial.

US Ambassador to India Ken Juster apologised for the incident.

"So sorry to see the desecration of the Gandhi statue in Wash, DC. Please accept our sincere apologies," he said.

"Appalled as well by the horrific death of George Floyd and the awful violence and vandalism. We stand against prejudice & discrimination of any type. We will recover and be better," he said in a tweet last week.

One of the few statues of a foreign leader on a federal land in Washington DC, the statue of Gandhi was dedicated by former prime minister Atal Bihari Vajpayee in the presence of the then US president Bill Clinton on September 16, 2000, during his state visit to the US.