Trump set to clamp down on H-1B visas

Washington, Jan 3: US President Donald Trump ordered the killing of Iran Revolutionary Guards commander Qasem Soleimani, who died in Baghdad "in a decisive defensive action to protect US personnel abroad," the Pentagon said Thursday.

"General Soleimani was actively developing plans to attack American diplomats and service members in Iraq and throughout the region. General Soleimani and his Quds Force were responsible for the deaths of hundreds of American and coalition service members and the wounding of thousands more," the Department of Defense said.

Following Soleimani's death, Trump tweeted an image of the US flag without any further explanation.

"US' act of international terrorism, assassinating General Soleimani—the most effective force fighting Daesh (ISIS), Al Nusrah,Al Qaeda, is extremely dangerous & foolish escalation. US bears responsibility for all consequences of rogue adventurism." said Iran Foreign Minister Javad Zarif.

Moscow, Jun 27: The number of people who have contracted the coronavirus infection in Russia has increased by 6,852 over the past day to a total of 627,646, the country's COVID-19 Response Center said in a daily update on Saturday.

"Over the past day, 6,852 new COVID-19 cases were confirmed in 85 regions of Russia, including 2,058, or 30 per cent, of asymptomatic cases," the response centre said.

Of the total 6,852 newly detected cases, 750 have been confirmed in Moscow, 366 in Moscow Region, and 280 in the Khanty-Mansi Autonomous Area, according to the report.

The reported daily dynamics included 188 new fatalities, which brought the cumulative death toll to 8,969.

Total recoveries now count 393,352, an increase of 9,200 over the past day, including 1,852 in Moscow, 1,421 in Moscow Region and 716 in St. Petersburg.

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.