Passengers freed from plane hijacked by Gaddafi loyalists

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 coronavirus pandemic has sickened more than 2,425,000 people, according to official counts. So far at least 164,000 people have died, and the virus has been detected in at least 177 countries, as the following table shows.

Washington, Feb 5: Experts warned a US government panel last night that India's Muslims face risks of expulsion and persecution under the country’s new Citizenship Amendment Act (CAA) which has triggered major protests.

The hearing held inside Congress was called by the US Commission on International Freedom, which has been denounced by the Indian government as biased.

Ashutosh Varshney, a prominent scholar of sectarian violence in India, told the panel that the law championed by prime minister Narendra Modi's government amounted to a move to narrow the democracy's historically inclusive and secular definition of citizenship.

"The threat is serious, and the implications quite horrendous," said Varshney, a professor at Brown University.

"Something deeply injurious to the Muslim minority can happen once their citizenship rights are taken away," he said.

Varshney warned that the law could ultimately lead to expulsion or detention -- but, even if not, contributes to marginalization.

"It creates an enabling atmosphere for violence once you say that a particular community is not fully Indian or its Indianness in grave doubt," he said.

India's parliament in December passed a law that fast-tracks citizenship for persecuted non-Muslim minorities from neighboring countries.

Responding to criticism at the time from the US commission, which advises but does not set policy, India's External Affairs Ministry said the law does not strip anyone's citizenship and "should be welcomed, not criticized, by those who are genuinely committed to religious freedom."

Fears are particularly acute in Assam, where a citizens' register finalized last year left 1.9 million people, many of them Muslims, facing possible statelessness.

Aman Wadud, a human rights lawyer from Assam who traveled to Washington for the hearing, said that many Indians lacked birth certificates or other documentation to prove citizenship and were only seeking "a dignified life."

The hearing did not exclusively focus on India, with commissioners and witnesses voicing grave concern over Myanmar's refusal to grant citizenship to the Rohingya, the mostly Muslim minority that has faced widespread violence.

Gayle Manchin, the vice chair of the commission, also voiced concern over Bahrain's stripping of citizenship from activists of the Shiite majority as well as a new digital ID system in Kenya that she said risks excluding minorities.

More than 40 people were killed last week in New Delhi in sectarian violence sparked by the citizenship law.

India on Tuesday lodged another protest after the UN human rights chief, Michele Bachelet, sought to join a lawsuit in India that challenges the citizenship law's constitutionality.