Oppositon queries not addressed at all-party meet: Mallikarjun Kharge

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, Mar 22: The central government on Sunday decided to suspend all metro train services across the country till March 31 in view of coronavirus outbreak.

In a message to managing directors of all metro train corporations, Union Housing and Urban Affairs Secretary Durga Shanker Mishra said this is being done in continuation of suspending metro services during 'Janta Curfew'.

"In view of the current global pandemic of this Corona Virus & for containing its further spread through inter-personal proximity, it has been decided to close down metro rail services on all operational networks across the country till 31 March 2020," Mishra tweeted.

In another tweet, he said by the act of social distancing, people can protect themselves and their dear ones, and win the fight against COVID-19.

India reported three more coronavirus deaths on Sunday, including the first casualty from Bihar, taking the toll to seven and the number of COVID-19 cases rose to 341, officials said.

Riyadh, Apr 22: In an extraordinary initiative, the government of the Kingdom of Saudi Arabia has decided to facilitate the travel of expatriates who have an exit and reentry visa or final exit visa to return to their countries.

This is in line with the order of Custodian of the Two Holy Mosques King Salman, according to the Saudi Press Agency.

According to the initiative, called “Auda” (return), expatriates can apply seeking permission for travel to their countries through the Absher portal of the ministry.

Announcing this, Saudi's Ministry of Interior said that the initiative will be implemented in cooperation with a number of relevant government agencies.

Requests for travel from expatriates will be received and approved in coordination with the relevant authorities to complete their travel procedures on board international flights.

As per the initiative, a text message will be sent to the beneficiary stating the travel date, ticket number and reservation details, and by which the beneficiary can obtain his travel ticket and complete the travel procedures.

Clarifying the procedures for the travel, the ministry said that the applicant shall select the icon (Auda) after visiting the Absher portal and fill the following fields: iqama (residency permit) number, date of birth, mobile number, departure city and airport of arrival.

It is not mandatory for the expatriate to have his own Absher account for availing of the service, the ministry said, adding that this facility is to enable expatriates to benefit from this initiative.

The departure will be through the following airports: King Khalid International Airport in Riyadh, King Abdulaziz International Airport in Jeddah, Prince Muhammad International Airport in Madinah, and King Fahd International Airport in Dammam.

Those expatriates who are outside these cities can benefit from the service through entering airport of departure after completion of their travel procedures in sufficient period of time.