Shahid Khaqan Abbasi elected Pakistan PM by National Assembly

Mar 6: UK stocks fell again on Friday as growing economic risks from the coronavirus outbreak shattered investor confidence, with Britain recording its first death from the pathogen.

A 1.5% fall for the FTSE 100 erased the blue-chip index's gains from earlier this week. Export-heavy companies have now lost over $230 billion in value since the epidemic sparked a worldwide rout last week.

The domestically focussed mid-cap index was down 1.9%.

Cruise operator Carnival dropped 4.2% to its lowest level since 2012, a day after its Grand Princess ocean liner was barred from returning to its home port of San Francisco on virus fears.

Britain said an older person with underlying health problems had succumbed to the flu-like virus on Thursday, while the number of infections jumped to 115.

In company news, drug maker AstraZeneca fell 1% after it said its treatment for a form of bladder cancer failed to meet the main goal of improving overall survival in patients in a late-stage study.

Kabul, May 11: Four back-to-back roadside bombs exploded in a northern district of Afghanistan's capital Kabul on Monday, wounding four civilians including a child, police said. Kabul police spokesman Ferdaws Faramarz said a clearance team was at the site of the attacks.

Militants have carried out several roadside bombings and rocket attacks in Kabul and other parts of the country in recent weeks, but Monday's four consecutive explosions appeared to be the first coordinated effort for some months.

The Taliban has not carried out any large attacks in the city since they signed a landmark withdrawal deal with the US in February, meant to pave the way for peace in the country. No group has claimed the attacks. The explosions come as authorities are trying to impose a lockdown in the capital to curb the spread of coronavirus in the country.

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.