For killing Indian techie Srinivas Kuchibhotla, US man faces death or life in prison

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 total number of global COVID-19 cases was nearing 9 million, while the deaths have increased to over 467,000, according to the Johns Hopkins University.

By Monday morning, the total number of cases stood at 8,927,195, while the fatalities increased to 467,636, the University's Center for Systems Science and Engineering (CSSE) revealed in its latest update.

With 2,279,306 cases and 119,967 deaths, the US continues with the world's highest number of COVID-19 infections and fatalities, according to the CSSE.

Brazil comes in the second place with 1,083,341 infections and 50,591 deaths.

In terms of cases, Russia ranks third (583,879), and was followed by India (410,461), the UK (305,803), Peru (251,338), Spain (246,272), Chile (242,355), Italy (238,499), Iran (204,952), France (197,008), Germany (191,272), Turkey (187,685), Mexico (180,545), Pakistan (176,617), Saudi Arabia (157,612), Bangladesh (112,306) and Canada (103,078), the CSSE figures showed.

The other countries with over 10,000 deaths are the UK (42,717), Italy (34,634), France (29,643), Spain (28,323), Mexico (21,825) and India (13,254).

Lucknow, Feb 14: Uttar Pradesh doctor Kafeel Khan was on Friday booked under the National Security Act (NSA) over his alleged anti-CAA speech at Aligarh Muslim University on December 12, 2019.

The Uttar Pradesh slapped NSA on Kafeel Khan on Friday even as the doctor waited to be released from jail despite being granted bail on Monday in connection with his alleged inflammatory speech.

SP Crime Dr Arvind said that there were sufficient grounds to book the doctor under NSA.

The suspended pediatrician, Kafeel Khan, was arrested for allegedly delivering a controversial speech during Anti-CAA protests on December 12 at the Aligarh Muslim University or AMU. While he was granted bail on Monday, his family members claimed on Thursday that he was yet to be released.

Dr Kafeel Khan's brother Adeel Ahmed Khan had issued a statement saying that despite being granted bail Mathura jail authorities had not honoured the court's order.

Dr Kafeel Khan was arrested by the UP Special Task Force from Mumbai on January 29 for participating anti-CAA protest at AMU. A case was registered against him at the Civil Lines police station here for promoting enmity between different religions.

After his arrest in Mumbai, Dr Khan was brought to Aligarh, from where he was shifted to the district jail in neighbouring Mathura.

According to police, this was done as a precautionary measure in view of the anti-CAA protests on the AMU campus and at the Eidgah grounds in the old city. Police had said that the Dr Khan's presence in the Aligarh jail could have aggravated the law and order situation in the city.

The doctor was earlier arrested for his alleged role in the death of over 60 children in one week at the BRD Medical College in Gorakhpur in August 2017. Short supply of oxygen at the children's ward was blamed at that time for the deaths.

About two years later, a state government probe cleared Khan of all major charges, prompting him to seek an apology from the Yogi Adityanath government.