Trump blasts courts for blocking travel ban, warns of 'peril'

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.

Washington, Jul 15: The Trump administration has agreed to rescind its July 6 rule, which temporarily barred international students from staying in the United States unless they attend at least one in-person course, a federal district court judge said on Tuesday.

The U-turn by the Trump administration comes following a nationwide outrage against its July 6 order and a series of lawsuits filed by a large number of educational institutions, led by the prestigious Harvard University and Massachusetts Institute of Technology (MIT), seeking a permanent injunctive relief to bar the Department of Homeland Security (DHS) and the US Immigration and Customs Enforcement (ICE) from enforcing the federal guidelines barring international students attending colleges and universities offering only online courses from staying in the country.

As many as 17 US states and the District of Columbia, along with top American IT companies such as Google, Facebook and Microsoft, joined MIT and Harvard in the US District Court in Massachusetts against the DHS and the ICE in seeking an injunction to stop the entire rule from going into effect.

"I have been informed by the parties that they have come to a resolution. They will return to the status quo," Judge Allison Burroughs, the federal district judge in Boston, said in a surprise statement at the top of the hearing on the lawsuit.

The announcement comes as a big relief to international students, including those from India. In the 2018-2019 academic year, there were over 10 lakh international students in the US. According to a recent report of the Student and Exchange Visitor Program (SEVP), 1,94,556 Indian students were enrolled in various academic institutions in the US in January.

Judge Burroughs said the policy would apply nationwide.

"Both the policy directive and the frequently asked questions would not be enforced anyplace," she said, referring to the agreement between the US government and MIT and Harvard.

Congressman Brad Scneider said this is a great win for international students, colleges and common sense.

"The Administration needs to give us a plan to tackle our public health crisis - it can't be recklessly creating rules one day and rescinding them the next," he said in a tweet.

Last week, more than 136 Congressmen and 30 senators wrote to the Trump administration to rescind its order on international students.

"This is a major victory for the students, organisers and institutions of higher education in the #MA7 and all across the country that stood up and fought back against this racist and xenophobic rule," said Congresswoman Ayanna Pressley.

"Taking online classes shouldn't force international students out of our country," Congressman Mikie Sherrill said in a tweet.

In its July 6 notice, the ICE had said all student visa holders, whose university curricula were only offered online, "must depart the country or take other measures, such as transferring to a school with in-person instruction to remain in lawful status".

"If not, they may face immigration consequences, including but not limited to the initiation of removal proceedings," it had said.

In their lawsuit, the 17 states and the District of Columbia said for many international students, remote learning in the countries and communities they come from would impede their studies or be simply impossible.

The lawsuit alleged that the new rule imposes a significant economic harm by precluding thousands of international students from coming to and residing in the US and finding employment in fields such as science, technology, biotechnology, healthcare, business and finance, and education, and contributing to the overall economy.

In a separate filing, companies like Google, Facebook and Microsoft, along with the US Chamber of Commerce and other IT advocacy groups, asserted that the July 6 ICE directive will disrupt their recruiting plans, making it impossible to bring on board international students that businesses, including the amici, had planned to hire, and disturb the recruiting process on which the firms have relied on to identify and train their future employees.

The July 6 directive will make it impossible for a large number of international students to participate in the CPT and OPT programmes. The US will "nonsensically be sending...these graduates away to work for our global competitors and compete against us...instead of capitalising on the investment in their education here in the US", they said.