U.K. excludes India from relaxed student visa rules

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.

Moscow, Jul 2: Russian voters approved changes to the constitution that will allow President Vladimir Putin to hold power until 2036, but the weeklong plebiscite that concluded Wednesday was tarnished by widespread reports of pressure on voters and other irregularities.

With most of the nation's polls closed and 20% of precincts counted, 72% voted for the constitutional amendments, according to election officials.

For the first time in Russia, polls were kept open for a week to bolster turnout without increasing crowds casting ballots amid the coronavirus pandemic a provision that Kremlin critics denounced as an extra tool to manipulate the outcome.

A massive propaganda campaign and the opposition's failure to mount a coordinated challenge helped Putin get the result he wanted, but the plebiscite could end up eroding his position because of the unconventional methods used to boost participation and the dubious legal basis for the balloting.

By the time polls closed in Moscow and most other parts of Western Russia, the overall turnout was at 65%, according to election officials. In some regions, almost 90% of eligible voters cast ballots.

On Russia's easternmost Chukchi Peninsula, nine hours ahead of Moscow, officials quickly announced full preliminary results showing 80% of voters supported the amendments, and in other parts of the Far East, they said over 70% of voters backed the changes.

Kremlin critics and independent election observers questioned the turnout figures.

We look at neighboring regions, and anomalies are obvious there are regions where the turnout is artificially (boosted), there are regions where it is more or less real, Grigory Melkonyants, co-chair of the independent election monitoring group Golos, told The Associated Press.

Putin voted at a Moscow polling station, dutifully showing his passport to the election worker. His face was uncovered, unlike most of the other voters who were offered free masks at the entrance.

The vote completes a convoluted saga that began in January, when Putin first proposed the constitutional changes.

He offered to broaden the powers of parliament and redistribute authority among the branches of government, stoking speculation he might seek to become parliamentary speaker or chairman of the State Council when his presidential term ends in 2024.

His intentions became clear only hours before a vote in parliament, when legislator Valentina Tereshkova, a Soviet-era cosmonaut who was the first woman in space in 1963, proposed letting him run two more times.

The amendments, which also emphasize the primacy of Russian law over international norms, outlaw same-sex marriages and mention a belief in God as a core value, were quickly passed by the Kremlin-controlled legislature.

Putin, who has been in power for more than two decades longer than any other Kremlin leader since Soviet dictator Josef Stalin said he would decide later whether to run again in 2024.

He argued that resetting the term count was necessary to keep his lieutenants focused on their work instead of darting their eyes in search for possible successors.

Analyst Gleb Pavlovsky, a former Kremlin political consultant, said Putin's push to hold the vote despite the fact that Russia has thousands of new coronavirus infections each day reflected his potential vulnerabilities.

Putin lacks confidence in his inner circle and he's worried about the future, Pavlovsky said.

He wants an irrefutable proof of public support.

Even though the parliament's approval was enough to make it law, the 67-year-old Russian president put his constitutional plan to voters to showcase his broad support and add a democratic veneer to the changes.

But then the coronavirus pandemic engulfed Russia, forcing him to postpone the April 22 plebiscite.

The delay made Putin's campaign blitz lose momentum and left his constitutional reform plan hanging as the damage from the virus mounted and public discontent grew.

Plummeting incomes and rising unemployment during the outbreak have dented his approval ratings, which sank to 59%, the lowest level since he came to power, according to the Levada Center, Russia's top independent pollster.

Moscow-based political analyst Ekaterina Schulmann said the Kremlin had faced a difficult dilemma: Holding the vote sooner would have brought accusations of jeopardizing public health for political ends, while delaying it raised the risks of defeat.

Holding it in the autumn would have been too risky, she said.

In Moscow, several activists briefly lay on Red Square, forming the number 2036 with their bodies in protest before police stopped them.

Some others in Moscow and St. Petersburg staged one-person pickets and police didn't intervene.

Several hundred opposition supporters rallied in central Moscow to protest the changes, defying a ban on public gatherings imposed for the coronavirus outbreak. Police didn't intervene and even handed masks to the participants.

Authorities mounted a sweeping effort to persuade teachers, doctors, workers at public sector enterprises and others who are paid by the state to cast ballots. Reports surfaced from across the vast country of managers coercing people to vote.

The Kremlin has used other tactics to boost turnout and support for the amendments.

Tezpur (Assam), Mar 2: Seven boys, who had appeared for their class 10 board examinations, were apprehended on Sunday for allegedly raping and killing a 12-year-old girl in Assam's Biswanath district, police said.

The girl was hanged from a tree after the crime.

The incident happened on Friday in Chakla village under the jurisdiction of Gohpur police station, they said.

A senior police officer told PTI that the culprits, all of them High School Leaving Certificate (HSLC) examinees, were on the run, but were nabbed by a police team.

The accused after the examination had called the victim to a house on the pretext of organising a party and raped her, the officer said.

It is suspected that the girl was raped on Friday night and then hanged from a tree in a forest near the house, the senior police officer said.

The body was found on Saturday.