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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.

Jammu, Jan 6: Union Minister Jitendra Singh on Sunday said India is the only shelter for religiously persecuted Hindus, Sikhs and other minorities who come from Pakistan, Bangladesh or Afghanistan, for the safety of their life and honour.

"India owes responsibility towards the minorities living in these countries which proclaim Islam as their state religion," Singh said here while launching the BJP's countrywide 10-day mass contact drive to spread awareness about the Citizenship Amendment Act (CAA).

Accompanied by senior party colleagues, including former deputy chief minister Kavinder Gupta and former minister Sat Sharma, he began by visiting the house of veteran columnist, writer and Padmashri awardee K L Pandita, where he spent time with them discussing the Act.

Later, he visited prominent social activist Amjad Mirza, eminent Sikh religious leader Baba Swaranjit Singh, retired High Court judge Justice G D Sharma, veteran journalist and former bureau head of Hind Samachar group Gopal Sachar, retired principal of Jammu government medical college Subhash Gupta, social activist and president of Peoples' Forum Ramesh Sabharwal, among others.

During his interaction with them, the Minister of State in the Prime Minister's Office claimed that Congress leaders and their allies protesting against the Act are doing so without "conviction".

He opined that if a "survey" was conducted among the family members of these Congress leaders, then, even they would not support their "anti-CAA stand".

"The tragedy of Congress party and contemporary leaders of Congress is that either they do not read their own history or are blissfully ignorant of the statements made by their own party patriarchs and former prime ministers," he said.

The minister recalled that the Nehru-Liaquat Pact of 1950 was inspired by the realisation on the part of the then Congress government headed by prime minister Jawaharlal Nehru that minorities, particularly Hindus, were not getting a fair deal in Pakistan.

"In 1949, Nehru had written a letter expressing concern about people coming in from then East Pakistan, which is now Bangladesh, and while doing so, he had referred to Hindus coming from there as 'refugees' and Muslims arriving here as 'immigrants'," Singh said.

Further, Nehru had stated that India owed a "responsibility" to these refugees, the minister said.

Referring to the opposition of senior Congress leaders Rahul Gandhi and Priyanka Gandhi to the amended legislation, the minister said someone should show them records of proceedings of the winter session of Parliament in 1950 when their great-grandfather (Nehru) had himself said that they deserved to be given citizenship and if the law was inadequate for it, then, the law should be changed.

"PM Modi should actually be given credit for showing courage and conviction to carry forward the task, which the Congress government lacked, to accomplish this," the minister opined.

Singh reiterated that a false fear psychosis against Muslims is being sought to be manufactured when there is no place as safe and comfortable to live for the community as India.

Turning the tables on the opposition to the National Population Register(NPR) and proposed National Register of Citizens (NRC), Singh pointed out that PM Modi and Union Home Minister Amit Shah have been stating that the exercise on NRC is yet to begin.

He also said that it was then Union home minister P Chidambaram, who had stated in Parliament in 2010 that NPR could be a basis for NRC.