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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.

Paris, Mar 2: A global agency says the spreading new virus could make the world economy shrink this quarter, for the first time since the international financial crisis more than a decade ago.

The Organization for Economic Cooperation and Development says Monday in a special report on the impact of the virus that the world economy is still expected to grow overall this year and rebound next year.

But it lowered its forecasts for global growth in 2020 by half a percentage point, to 2.4 per cent, and said the figure could go as low as 1.5 per cent if the virus lasts long and spreads widely.

The last time world GDP shrank on a quarter-on-quarter basis was at the end of 2008, during the depths of the financial crisis. On a full-year basis, it last shrank in 2009.

The OECD said China's reduced production is hitting Asia particularly hard but also companies around the world that depend on its goods.

It urged governments to act fast to prevent contagion and restore consumer confidence.

The Paris-based OECD, which advises developed economies on policy, said the impact of this virus is much higher than past outbreaks because "the global economy has become substantially more interconnected, and China plays a far greater role in global output, trade, tourism and commodity markets."

Tokyo, Mar 4: Takeda Pharmaceutical Co said on Wednesday it was developing a drug to treat COVID-19, the flu-like illness that has struck more than 90,000 people worldwide and killed over 3,000.

The Japanese drugmaker is working on a plasma-derived therapy to treat high-risk individuals infected with the new coronavirus and will share its plans with members of the U.S. Congress on Wednesday, it said in a statement.

Takeda is also studying whether its currently marketed and pipeline products may be effective treatments for infected patients.

"We will do all that we can to address the novel coronavirus threat...(and) are hopeful that we can expand the treatment options," Rajeev Venkayya, president of Takeda's vaccine business, said in the statement.

Takeda said it was in talks with various health and regulatory agencies and healthcare partners in the United States, Asia and Europe to move forward its research into the drug.

Its research requires access to the blood of people who have recovered from the respiratory disease or who have been vaccinated, once a vaccine is developed, Takeda said.