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Melbourne, Jul 24: Home-made cloth face masks may need a minimum of two layers, and preferably three, to prevent the dispersal of viral droplets associated with Covid-19, according to a study.

Researchers, including those from the University of New South Wales in Australia, noted that viral droplets are generated by those infected with the novel coronavirus when they cough, sneeze, or speak.

As face masks have been proven to protect healthy people from inhaling infectious droplets as well as reducing the spread from those who are already infected, several types of material have been suggested for these, but based on little or no evidence of how well they work, the scientists said.

In the current study, published in the journal Thorax, the researchers compared the effectiveness of single and double-layer cloth face coverings with a surgical face mask (Bao Thach) at reducing droplet spread.

They said the single layer covering was made from a folded piece of cotton T shirt and hair ties, and the double layer covering was made using the sew method described by the US Centers for Disease Control and Prevention (CDC).

The scientists used a tailored LED lighting system and a high-speed camera to film the dispersal of airborne droplets produced by a healthy person with no respiratory infection, during speaking, coughing, and sneezing while wearing each type of mask.

Their analysis showed that the surgical face mask was the most effective at reducing airborne droplet dispersal, although even a single layer cloth face covering reduced the droplet spread from speaking.

But the study noted that a double layer covering was better than a single layer in reducing the droplet spread from coughing and sneezing.

According to the researchers, the effectiveness of cloth face masks is dependent on the number of layers of the covering, the type of material used, design, fit as well as the frequency of washing.

Based on their observations, they said a home made cloth mask with at least two layers is preferable to a single layer mask.

"Guidelines on home-made cloth masks should stipulate multiple layers," the scientists said, adding that there is a need for more research to inform safer cloth mask design.

San Francisco, Mar 18: Facebook said a bug in its anti-spam system temporarily blocked the publication of links to news stories about the coronavirus. Guy Rosen, Facebook's vice president of integrity, said on Twitter Tuesday that the company was working on a fix for the problem.

Users complained that links to news stories about school closings and other information related to the virus outbreak were blocked by the company's automated system.

Later on Tuesday, Rosen tweeted that Facebook had restored all the incorrectly deleted posts, which also covered topics beyond the coronavirus.

Rosen said the problems were unrelated to any changes in Facebook's content-moderator workforce. The company reportedly sent its human moderators home this week because of the coronavirus outbreak.

A representative for Facebook did not immediately respond to questions on the status of Facebook's content moderators, many of whom do not work directly for the company and are not always able to work from home.

New Delhi, May 10: Congress leader Rahul Gandhi on Saturday demanded that Prime Minister Narendra Modi ensured audit of donations made to the PM-CARES Fund, and to share the details and the money spent with the people.

"The PM-CARES Fund has received huge contributions from PSUs and major public utilities like the Railways. It's important that the Prime Minister ensure the fund is audited and that the record of money received and spent is available to the public," he tweeted.

The #PmCares fund has received huge contributions from PSUs & major public utilities like the Railways.

It’s important that PM ensures the fund is audited & that the record of money received and spent is available to the public.

— Rahul Gandhi (@RahulGandhi) May 9, 2020
His remarks came amid reports that the central government is accumulating a huge sum of money in the Prime Minister's Citizen Assistance and Relief in Emergency Situations Fund set up as a corpus to fight novel coronavirus and that the amount spent will not be audited by the Comptroller and Auditor General.

The CAG office had clarified that since the fund is based on donations, it has no right to audit a charitable organisation.

On Friday, Rahul Gandhi told the media that the PM-CARES Fund should be audited and people of the country should know about the donors and the donations made.