Armed forces quelling terror, oppn seeking proof: PM Modi

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, Jan 14: The curative petitions of Vinay Sharma and Mukesh, who were sentenced to death in the Nirbhaya gang rape and murder case, was on Tuesday rejected by a five-judge Supreme Court Bench led by Justice N.V. Ramana.

In a three-page order, the Bench concluded, after an in chamber consideration that began about 1.45 p.m., that there was no merit in their pleas to spare them from the gallows.

“We have gone through the curative petitions and relevant documents. In our opinion, no case is made out within the parameters indicated in the decision of this Court in Rupa Ashok Hurra versus Ashok Hurra. Hence, the curative petitions are dismissed,” the court held.

Curative is a rare remedy devised by a Constitution Bench of the Supreme Court in its judgment in the Rupa Ashok Hurra case in 2002. A party can take only two limited grounds in a curative petition - one, he was not heard by the court before the adverse judgment was passed, and two, the judge was biased. A curative plea, which follows the dismissal of review petition, is the last legal avenue open for convicts in the Supreme Court. Sharma was the first among the four convicts to file a curative.

The Bench also rejected their pleas to stay the execution of their death sentence and for oral hearing in open court.

Besides Justice Ramana, the Bench comprised Arun Mishra, Rohinton Nariman, R. Banumathi and Ashok Bhushan.

Curative petitions were filed in the Supreme Court by both convicts on January 9. The petitions had come just days after a Delhi sessions court schedulled the execution of all the four convicts in Tihar jail on January 22.

Sharma and Mukesh, in separate curative petitions, argued that there was a “sea change” in the death penalty jurisprudence since their convictions. Carrying out the death sentence on such changed circumstances would be a “gross miscarriage of justice”.

In his plea, Sharma said the Court had commuted the death penalty in several rape and murder cases since 2017, when it first confirmed the death penalty to the Nirbhaya convicts.

“fter the pronouncement of judgment in 2017, there have been as many as 17 cases involving rape and murder in which various three-judge Benches of the Supreme Court have commuted the sentence of death,” the petition contended.

The Supreme Court recently dismissed a review petition filed by Akshay Singh, another of the four four condemned men, to review its May 5, 2017 judgment confirming the death penalty. It also refused his plea to grant him three weeks' time to file a mercy petition before the President of India.

A Bench led by Justice R. Banumathi had said it was open for the Nirbhaya case convicts to avail whatever time the law prescribes for the purpose of filing a mercy plea.

Akshay (33), Mukesh (30), Pawan Gupta (23) and Sharma (24) had brutally gang-raped a 23-year-old paramedical student in a moving bus on the intervening night of December 16-17, 2012. She died of her injuries a few days later.

The case shocked the nation and led to the tightening of anti-rape laws. Rape, especially gang rape, is now a capital crime.

One of the accused in the case, Ram Singh, allegedly committed suicide in the Tihar jail. A juvenile, who was among the accused, was convicted by a juvenile justice board. He was released from a reformation home after serving a three-year term.