US to proceed with prosecution of Devyani Khobragade, no question of apology: Sources

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.

UN, May 26: Countries could see a "second peak" of coronavirus cases during the first wave of the pandemic if lockdown restrictions were lifted too soon, the World Health Organization (WHO) has warned.

Mike Ryan, the WHO's head of emergencies, told a briefing on Monday that the world was "right in the middle of the first wave", the BBC reported.

He said because the disease was "still on the way up", countries need to be aware that "the disease can jump up at any time".

"We cannot make assumptions that just because the disease is on the way down now that it's going to keep going down," Ryan said.

There would be a number of months to prepare for a second peak, he added.

The stark warning comes as countries around the world start to gradually ease lockdown restrictions, allowing shops to reopen and larger groups of people to gather.

Experts have said that without a vaccine to give people immunity, infections could increase again when social-distancing measures are relaxed.

Ryan said countries where cases are declining should be using this time to develop effective trace-and-test regimes to "ensure that we continue on a downwards trajectory and we don't have an immediate second peak".

Also on Monday, Tedros Adhanom Ghebreyesus, WHO Director-General, said that a clinical trial of hydroxychloroquine (HCQ) on COVID-19 patients has come to "a temporary pause", while the safety data of the the anti-malaria drug was being reviewed.

According to the WHO chief, The Lancet medical journal on May 22 had published an observational study on HCQ and chloroquine and its effects on COVID-19 patients that have been hospitalized, reports Xinhua news agency.

The authors of the study reported that among patients receiving the drug, when used alone or with a macrolide, they estimated a higher mortality rate.

"The Executive Group of the Solidarity Trial, representing 10 of the participating countries, met on Saturday (May 23) and has agreed to review a comprehensive analysis and critical appraisal of all evidence available globally," Tedros said in a virtual press conference.

The developments come as the total number of global COVID-19 cases has increased to 5,508,904, with 346,508 deaths, according to the Johns Hopkins University.

Washington, Jan 12: The US State Department has described the recent visit of envoys of 15 countries to Jammu and Kashmir as an "important step" but expressed concern over the continued detention of political leaders and restrictions on internet in the region.

Alice Wells, the Acting Assistant Secretary of State for South Asia, tweeted on Saturday that she was "closely following" the visit of the envoys to Kashmir, describing it an "important step".

Wells, who will be visiting India this week, added: "We remain concerned by detention of political leaders and residents and Internet restrictions. We look forward to a return to normalcy."

The group of diplomats made a two-day visit to the Union Territory on Thursday and Friday to see the conditions thereafter Jammu and Kashmir's special constitutional status was removed last August.

While some US politicians and media have criticised the action by Prime Minister Narendra Modi's government, the US has officially appeared to support the abrogation of the Constitution's Article 370 on the special status.

Last October, Wells told the House of Representatives Subcommittee on Asia and the Pacific that the State Department supported the objectives behind it, while not directly mentioning the abrogation.

"The Indian government has argued that its decision on Article 370 was driven by a desire to increase economic development, reduce corruption, and uniformly apply all national laws in Jammu and Kashmir, particularly in regard to women and minorities.

"While we support these objectives, the Department remains concerned about the situation in the Kashmir Valley, where daily life for the nearly eight million residents has been severely impacted since August 5," she had said.

Washington has banked on India's democratic institutions - the judiciary and public debates - being able to steer the country.

Bearing this out, the Supreme Court last week ordered the government to review its decision to shut down the internet in Kashmir, which it declared was a fundamental right, thus taking a step to address Wells's concern.