21 Gir lions dead, 4 of virus that killed 1,000 in Serengeti

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.

In a bid to help tackle rise in domestic violence during the social distancing times in India, Twitter on Wednesday launched a dedicated search prompt to serve information and updates from authoritative sources around domestic violence.

Twitter has partnered with the Ministry of Women and Child Development the National Commission for Women in India to expand its efforts towards women.

The search prompt will be available on iOS, Android and on mobile.twitter.com in India, in both English and Hindi languages, the company said in a statement.

Data shows that since the outbreak of Covid-19, violence against women and girls has intensified in India and across the globe.

"We recognise collaboration with the public, government and NGOs is key to combating the complex issue of domestic violence. Accessing reliable information through this search prompt could be a survivor's first step towards seeking help against abuse and violence," said Mahima Kaul, Director, Public Policy, India and South Asia, Twitter.

Every time someone searches for certain keywords associated with the issue of domestic violence, a prompt will direct them to the relevant information and sources of help available on Twitter.

This is an expansion of Twitter's #ThereIsHelp prompt, which was specifically put in place for the public to find clear, credible information on critical issues.

The feature will be reviewed at regular intervals by the Twitter team to ensure that all related keywords generate the proactive search prompt, said the company.

Violence against women and girls across Asia Pacific is pervasive but at the same time widely under reported.

"In fact, in many countries in our region, the number is even greater, with as many as 2 out of 3 women in some countries reporting experiences of violence," added Melissa Alvarado, UN Women Asia Pacific Regional Manager on Ending Violence against Women.

Rekha Sharma, Chairperson, the NCW, said: "With social distancing norms in place, several women are unable to contact their regular support systems. This initiative by Twitter will provide big support to the survivors, who would otherwise be easily isolated without access to relevant information and help".

U.S. electric vehicle maker Tesla Inc is "very close" to achieving level 5 autonomous driving technology, Chief Executive Elon Musk said on Thursday, referring to the capability to navigate roads without any driver input.

"I'm extremely confident that level 5 or essentially complete autonomy will happen and I think will happen very quickly," Musk said in remarks made via a video message at the opening of Shanghai's annual World Artificial Intelligence Conference (WAIC).

"I remain confident that we will have the basic functionality for level 5 autonomy complete this year."

Automakers and tech companies including Alphabet Inc Waymo and Uber Technologies are investing billions in the autonomous driving industry.

However industry insiders have said it would take time for the technology to get ready and public to trust autonomous vehicles fully.

The California-based automaker currently builds cars with an Autopilot driver-assistance system.

Tesla is also developing new heat-projection or cooling systems to enable more advanced computers in cars, Musk said.

Industry data showed Tesla sold nearly 15,000 China-made Model 3 sedans last month.

Tesla has become the highest-valued automaker as its shares surged to record highs and its market capitalisation overtook that of former front-runner Toyota Motors Corp.