PM Modi celebrates Diwali with troops along LoC in J&K's Gurez

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 1: Amid the lockdown due to the COVID-19 pandemic, the University Grants Commission (UGC) and the Human Resource Development Ministry are planning to conduct the PhD and MPhil exams through online mediums in various universities across the country. The universities have been informed by the UGC and the MHRD about this.

Union Human Resource Development Minister Ramesh Pokhriyal 'Nishank' said, "Phd, MPhil exams, practicals, viva etc can be conducted through Skype or any other meeting apps."

When this system is implemented in colleges, students will not have to wait long for various types of examinations. Especially internal examinations can be taken online. Students' viva tests can also be conducted via Skype or any other similar meeting apps.

Regular classes in the universities will resume after the lockdown is removed. The classes for the first year will start from September 1 while for the second and third years the classes will start from August 1. However, students of various colleges will have to appear for basic exams in July.

A special committee constituted by the UGC has emphasized on conducting examinations online. The committee in its recommendation said that various colleges and universities should conduct online examinations including internal exams of colleges for 25 per cent marks.

The National Testing Agency (NTA), on the advice of the Ministry of Human Resource Development, has extended the date of filling the entrance examination forms for various universities.

According to the orders of the NTA, the date of filling the form for the entrance examinations of Jawaharlal Nehru University, National Council for Hotel Management 'G' and for Phd and MBA from IGNOU has been extended till May 15.

Beijing, Mar 21: China reported no domestically transmitted coronavirus cases for the third consecutive day even as seven more fatalities have been confirmed, taking the death toll in the country to 3255.

No new domestically transmitted cases of COVID-19 were reported on the Chinese mainland for the third day in a row on Friday, China's National Health Commission (NHC) said on Saturday.

The overall confirmed cases on the mainland had reached 81,008 by the end of Friday, which included 3,255 who died, 6,013 patients still undergoing treatment, 71,740 patients who had been discharged after recovery, the NHC said.

The NHC said 41 new confirmed COVID-19 cases were reported on the Chinese mainland on Friday from the people arriving from abroad, taking the total number of imported cases to 269.