Clouds do prevent radars from detecting accurately: Air Marshal Raghunath Nambiar

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 11: Shares of Indian Railway Catering And Tourism Corporation (IRCTC) jumped 5 per cent in early trade on Monday after the Indian Railways said it will gradually resume passenger train services from May 12.

The company's shares gained 5 per cent to Rs 1,302.85 -- its highest trading permissible limit for the day -- on the BSE. At the National Stock Exchange (NSE), it rose 5 per cent to Rs 1,303.55 -- its upper circuit limit.

Booking for reservation in these trains will start at 4pm on May 11 and will be available only on the IRCTC website.

The Indian Railways will gradually resume passenger train services from May 12 and will ask passengers to arrive at the station at least an hour before departure, the national transporter said on Sunday.

Initially, the all air-conditioned services will begin on 15 Rajdhani routes and the fare would be equivalent to that of the super-fast train, it said.

The special trains will run from New Delhi to Dibrugarh, Agartala, Howrah, Patna, Bilaspur, Ranchi, Bhubaneswar, Secunderabad, Bengaluru, Chennai, Thiruvananthapuram, Madgaon, Mumbai Central, Ahmedabad and Jammu Tawi.

All passenger services were suspended due to a lockdown announced on March 25 and the railways later started the on-demand Shramik Specials to ferry migrants stranded across the country. It, however, has been running freight and parcel services.

New Delhi, Feb 27: The US Commission on International Religious Freedom (USCIRF) has said that the Delhi violence in which over 30 people were killed, was specifically targeted against the Muslims.

Expressing "grave concern over the ongoing violence taking place in Delhi", the USCIRF in a statement said that as President Donald Trump's inaugural visit to India winds down, North-East Delhi has been rocked by deadly rioting, with reports of violence and mobs specifically targeting Muslims.

"These incidents are even more concerning in the context of efforts within India to target and potentially disenfranchise Muslims across the country, in clear violation of international human rights standards," USCIRF Commissioner Anurima Bhargava said.

"According to reports, several mosques have also been set alight or vandalized. Many Muslim residents have been forced to flee the area. This unrest comes in the wake of widespread protests against the Citizenship (Amendment) Act following its passage in December 2019.

"The brutal and unchecked violence growing across Delhi cannot continue," Bhargava said adding that the Indian government must take swift action to ensure the safety of all of its citizens.

"Instead, reports are mounting that the Delhi police have not intervened in violent attacks against Muslims, and the government is failing in its duty to protect its citizens."

USCIRF Chair Tony Perkins said the ongoing violence in Delhi and the reported "attacks against Muslims, their homes and shops, and their houses of worship are greatly disturbing".

One of the essential duties of any responsible government, he said, is to provide protection and physical security for its citizens, regardless of faith.

"We urge the Indian government to take serious efforts to protect Muslims and others targeted by mob violence."

In its annual report last year, the USCIRF classified India as a "Tier 2" country for engaging in or tolerating religious freedom violations that meet at least one of the elements of the "systematic, ongoing, egregious standard for designations as a "country of particular concern (CPC)", under the International Religious Freedom Act.

The ongoing violence in North-East Delhi erupted after clashes between pro and anti-CAA protesters on Sunday.

Besides the casualties, over 200 others have been injured in the deadliest violence in the national capital in decades.