ISIS chief Abu Bakr al-Baghdadi killed in US raid in Syria: Trump

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, Mar 3: Delhi's Tihar Prison authorities had made all necessary preparations for the hanging of four convicts in the Nirbhaya gangrape-and-murder case which was scheduled for Tuesday, officials said Monday.

However, on Monday evening, a city court deferred the hanging till further orders.

Postponing the execution, Additional Sessions Judge Dharmender Rana said the hanging cannot be carried out pending disposal of Pawan Gupta's mercy plea before the President, observing any condemned convict must not meet his "Creator" with grievance against courts for not acting fairly on the opportunity to exhaust legal remedies.

"We had made all the necessary arrangements for the execution of the four convicts which was scheduled for Tuesday at 6 AM. Now, the execution has been postponed and we are waiting for the further order by the court," a senior jail official said.

The hanging of the four men -- Mukesh Kumar Singh (32), Vinay Kumar Sharma (26), Akshay Kumar Singh (31) and Pawan -- who are lodged in Tihar jail, was fixed for March 3 in Tihar jail on a court order.

"We had checked the ropes. Hangman was called and dummy executions were carried out," another senior jail official said.

Barring Pawan, the other three had in the previous weeks moved curative petitions and mercy pleas which were all dismissed.

The first date of execution -- January 22 -- fixed on January 7 was postponed by the court to February 1. But on January 31, the court indefinitely postponed the hanging. On February 17, the court again issued fresh date for execution of death warrants for March 3 at 6 AM.

The court in its orders observed that the four convicts cannot be hanged since a mercy plea of one or the other convict was pending.

Jan 22: Microsoft Corp’s chief executive officer said he worries that mistrust between the US and China will increase technology costs and hurt economic growth at a critical time.

Using the $470 billion semiconductor industry as an example of a sector that is already globally interconnected, Satya Nadella said the two countries will have to find ways to work together, rather than creating different supply chains for each country.

“All you are doing is increasing transaction costs for everybody if you completely separate,” Nadella said in an interview with Bloomberg News Editor-in-Chief John Micklethwait at Bloomberg’s The Year Ahead conference in Davos. That’s a concern as the executive said the world is on the cusp of a revolution around technology and artificial intelligence.

“If we take steps back in trust or increase transaction costs around technology, all we are doing is sacrificing global economic growth,” he said.

The agreement signed last week between the US and China was “not sufficient,” said Nadella, but represented “progress” on the issue of intellectual property protections for US technology companies working with China.

Nadella said he worries about the development of two separate internets, noting that to some degree they already exist “and they will get amplified in the future” with massive technology companies already in place in China.

The viewpoint clashes with Microsoft co-founder Bill Gates, who has been sceptical about the idea that ongoing US-China trade tensions could ever lead to a bifurcated system of two internets.

China and the US are the two leading AI superpowers, however the cooling political relations between them have slowed the international collaboration.

Nadella also warned that countries that fail to attract immigrants will lose out as the global tech industry continues to grow. The CEO has previously voiced concern about India’s Citizenship Amendment Act, calling it “sad.”

“However, Nadella said he remained hopeful.

“The fact that there is a 70-year history of nation-building, I think it’s a very strong foundation. I grew up in that country. I’m proud of that heritage. I’m influenced by that experience.”