Astronomers discover 83 supermassive black holes 13 billion light-years away

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.

New Delhi, May 28: The Crime Branch of the Delhi Police will file 12 chargesheets against 536 Tablighi Jamaat members from three countries, officials said on Thursday.

Till now, the police has already filed chargesheets against 374 foreigners from 32 countries.

The officials said the charges against the Tablighi Jamaat members pertain to violation of visa rules, government guidelines regarding the Epidemic Disease Act and acting negligently in a way that was likely to spread infection of disease dangerous to life.

The Tablighi Jamaat, a religious organisation in Nizamuddin in South Delhi, had allegedly organised a congregation in March in violation of mass gatherings.

The Tablighi Jamaat’s Nizamuddin Markaz (centre) had become a coroavirus hotspot in the national capital.

Mumbai, Mar 13:  Investor wealth worth nearly Rs 12 lakh crore was wiped out in less than 15 minutes of trading on the stock exchanges on Friday, with the two benchmarks, the BSE Sensex and the NSE Nifty, crashing over 10 per cent.

The 30-share BSE Sensex plummeted 3,380.59 points, or 10.31 per cent, to 29,397.55. It hit an intra-day low of 29,388.97, falling up to 3,389.17 points.

Trading was halted for 45 minutes in the early session after the index hit its lower circuit limit.

The BSE and NSE benchmark indices, however, pared most losses with the Sensex trading 835.40 points, or 2.55 per cent, lower at 31,942.74, and the Nifty was down 253.25 points or 2.64 per cent at 9,336.90 at 10.40 am.

The mayhem on Dalal Street eroded investor wealth worth Rs 12,92,479.88 crore, taking the total m-cap to Rs 1,12,78,172.75 crore on the BSE at 1020 hours.

The m-cap of BSE-listed companies stood at Rs 1,25,70,652.63 crore at the end of trading on Thursday.

Traders said besides global selloff, incessant foreign fund outflows also weighed on investor sentiments.

On a net basis, foreign institutional investors sold equities worth Rs 3,475.29 crore on Thursday, data available with stock exchanges showed.

On the BSE, 1,279 scrips declined, while 193 advanced and 40 remained unchanged.

Volatility heightened in global markets as benchmarks world over went into panic mode, insinuating a freakish selloff.

Bourses in Shanghai dropped over 3.32 per cent, Hong Kong 5.61 per cent, Seoul 7.58 per cent and Tokyo cracked up to 7.97 per cent.

Wall Street lost 10 per cent in overnight trade.

More than 1,30,000 cases of the novel coronavirus have been recorded in 116 countries and territories, killing at least 4,900 people.

The number of coronavirus patients in India has risen to 74, as per the health ministry.