United States donates 100 ventilators worth $3 million to Pakistan

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.

Kensington (United States), May 20: The world cut its daily carbon dioxide emissions by 17% at the peak of the pandemic shutdown last month, a new study found.

But with life and heat-trapping gas levels inching back toward normal, the brief pollution break will likely be “a drop in the ocean" when it comes to climate change, scientists said.

In their study of carbon dioxide emissions during the coronavirus pandemic, an international team of scientists calculated that pollution levels are heading back up — and for the year will end up between 4% and 7% lower than 2019 levels.

That's still the biggest annual drop in carbon emissions since World War II.

It'll be 7% if the strictest lockdown rules remain all year long across much of the globe, 4% if they are lifted soon.

For a week in April, the United States cut its carbon dioxide levels by about one-third.

China, the world's biggest emitter of heat-trapping gases, sliced its carbon pollution by nearly a quarter in February, according to a study Tuesday in the journal Nature Climate Change. India and Europe cut emissions by 26% and 27% respectively.

The biggest global drop was from April 4 through 9 when the world was spewing 18.7 million tons (17 million metric tons) of carbon pollution a day less than it was doing on New Year's Day.

Such low global emission levels haven't been recorded since 2006. But if the world returns to its slowly increasing pollution levels next year, the temporary reduction amounts to ''a drop in the ocean," said study lead author Corinne LeQuere, a climate scientist at the University of East Anglia.

“It's like you have a bath filled with water and you're turning off the tap for 10 seconds," she said.

By April 30, the world carbon pollution levels had grown by 3.3 million tons (3 million metric tons) a day from its low point earlier in the month. Carbon dioxide stays in the air for about a century.

Outside experts praised the study as the most comprehensive yet, saying it shows how much effort is needed to prevent dangerous levels of further global warming.

“That underscores a simple truth: Individual behavior alone ... won't get us there,” Pennsylvania State University climate scientist Michael Mann, who wasn't part of the study, said in an email.

“We need fundamental structural change.”

If the world could keep up annual emission cuts like this without a pandemic for a couple decades, there's a decent chance Earth can avoid warming another 1.8 degrees (1 degree Celsius) of warming from now, study authors said. But getting the type of yearly cuts to reach that international goal is unlikely, they said.

If next year returns to 2019 pollution levels, it means the world has only bought about a year's delay in hitting the extra 1.8 degrees (1 degree Celsius) of warming that leaders are trying to avoid, LeQuere said. That level could still occur anywhere from 2050 to 2070, the authors said.

The study was carried out by Global Carbon Project, a consortium of international scientists that produces the authoritative annual estimate of carbon dioxide emissions. They looked at 450 databases showing daily energy use and introduced a measurement scale for pandemic-related societal “confinement” in its estimates.

Nearly half the emission reductions came from less transportation pollution, mostly involving cars and trucks, the authors said. By contrast, the study found that drastic reductions in air travel only accounted for 10% of the overall pollution drop.

In the US, the biggest pollution declines were seen in California and Washington with plunges of more than 40%.

Munich, Feb 16: Iran's foreign minister said Saturday that US President Donald Trump is receiving bad advice if he believes an American "maximum pressure" campaign against his country will cause the government in Tehran to collapse.

Foreign Minister Mohammad Javad Zarif told a group of top defense officials and diplomats at the Munich Security Conference that the information provided to the president has dissuaded Trump from accepting offers from other leaders to mediate between Washington and Tehran.

"President Trump has been convinced that we are about to collapse so he doesn't want to talk to a collapsing regime," Zarif said.

To support his argument, the Iranian minister cited Trump's decision to pull out unilaterally in 2018 from Iran's nuclear deal with the US and other world powers. Trump said the landmark 2015 accord didn't address Iran's ballistic missile program or regional activities and needed to be renegotiated.

Since then, the Trump administration's re-imposition of US sanctions in a campaign of so-called "maximum pressure" have taken a severe toll on the Iranian economy and sent Iran's currency plunging.

"I believe President Trump, unfortunately, does not have good advisers," Zarif said. "He's been wanting for Iran to collapse since he withdrew from the nuclear deal." Zarif also said the killing of Iranian Gen. Qassem Soleimani in a US drone strike in Iraq on January 3 was a miscalculation by Washington that has galvanized support for Iran instead of increasing pressure on the regime.

The Iran nuclear deal, known as the Joint Comprehensive Plan of Action or JCPOA, promised Iran economic incentives in exchange for curbs on its nuclear program. It was intended to prevent Tehran from developing a nuclear bomb, which Iran insists it does not want to do.

Since the US withdrawal, the deal's other signatories - Germany, France, Britain, Russia and China - have unsuccessfully struggled to come up with ways to offset the effects of the new American sanctions.

Washington has pressured the other countries - so far without success - to abandon the deal entirely US Secretary of State Mike Pompeo said at the Munich Security Conference earlier Saturday that while there may be disagreements on what to do with the JCPOA, "when I talk to my counterparts here in Europe, everybody gets it."

"Everyone understands that these are folks who continue to build out their nuclear program," Pompeo said. "So there's a common understanding about the threat; we have tactical differences on how to proceed."

In recent months, Iran has steadily violated the limitations the deal placed on the amount of enriched uranium and heavy water it can stockpile, the number and type of centrifuges it can operate, and the purity of the uranium it enriches.

Iranian officials insist the moves are intended only to put pressure on the countries that remain part of the deal to provide economic help to Iran and that all the measures taken are fully reversible.

Zarif rejected Trump's suggestion of negotiating a new deal, saying the one negotiated during the Obama administration was the only vehicle for talks on Iran's nuclear program.

"There is no point in talking over something you already talked about. You don't buy a horse twice," he said.

"It's not about opening talks with the United States. It's about bringing the United States to the negotiating table that's already there," Zarif said.