Rocket lands inside Indian Embassy in Kabul, no casualties

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.

Wellington, Mar 25: New Zealand has declared a state of emergency as it prepares to go into an unprecedented lockdown late Wednesday for about a month.

The declaration temporarily gives police and the military extra powers. And Prime Minister Jacinda Ardern says any New Zealanders returning home from overseas who show symptoms of COVID-19 will be put in isolation at an approved facility.

“I have one simple message for New Zealanders today as we head into the next four weeks: ‘stay at home,’” Ardern said. “It will break the chain of transmission and it will save lives.”

Ardern said exceptions include people working crucial jobs, those leaving to pick up essentials like groceries, and those engaging in solitary exercise.

The country has 205 reported cases of the virus, although Ardern said that number could rise into the thousands before it begins to recede even with the strict measures being taken.

New Delhi, Feb 10: Former Jammu and Kashmir chief minister Omar Abdullah's sister on Monday moved the Supreme Court to challenge his detention under the Public Safety Act.

Senior advocate Kapil Sibal, appearing for the petitioner, mentioned the matter for urgent listing before a bench headed by Justice N V Ramana.

Sibal told the bench that they have filed a habeas corpus petition challenging the detention of Abdullah under the PSA and the matter should be heard this week.

The bench agreed for urgent listing of the matter.