Russia seeking to undermine US reputation in Afghan, S. Asia

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.

London, May 21: Working mothers in Europe and the United States are taking on most of the extra housework and childcare created by lockdown - and many are struggling to cope, a survey showed on Thursday.

Women with children now spend an average 65 hours a week on the unpaid chores - nearly a third more than fathers - according to the Boston Consulting Group, which questioned parents in five countries.

"Women have been doing too much household work for too long, and this crisis is pushing them to a point that's simply unsustainable," Rachel Thomas, of U.S.-based women's rights group LeanIn.Org, said in response to the data.

"We need a major culture shift in our homes and in our companies ... We should use this moment to build a better way to work and live – one that's fair for everybody."

Researchers say fallout from the pandemic weighs on women in a host of ways, be it in rising domestic violence or in lower wages, as some women cut paid work to take on the new duties.

With lockdowns shutting schools and keeping citizens at home, creating a mountain of domestic work, public campaigns from Georgia to Mexico have urged men to do their fair share.

But women, who on average already do more at home than men, are now shouldering most of the new coronavirus burden, too, said the survey of more than 3,000 working parents in the United States, Britain, Italy, Germany and France.

Women's unpaid hours at home have nearly doubled to 65 hours a week, said the survey, against 50 logged by an average father.

British women are more likely to support others in the COVID-19 pandemic and are finding it harder to stay positive, according to separate analysis released this week by polling firm Ipsos MORI and feminist organisation The Fawcett Society.

It is "no surprise" to see women do more childcare and housekeeping on top of their day jobs, Jacqui Hunt of women's rights group Equality Now, told the Thomson Reuters Foundation.

However, there are "hopeful signs" that men in West Africa are sharing more childcare during the pandemic in a shift in social norms, found a small rapid analysis by humanitarian organisation CARE International released on Wednesday.