Saudi woman held at Bangkok airport pleads for asylum

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.

Dubai, July 6: Even as the world’s one of the most sought after tourist destinations is gearing up to welcome foreign tourists from July 7, the authorities have taken necessary measures to prevent the spread of covid-19.

If the foreign tourists want to avoid self-isolation after landing in Dubai International Airport, they have to fetch covid-negative certificates from their home country. The certificate ought to have been issued up to 96 hours prior to the travel.

Those without a cvid-negative certificate, however, will need to undergo a PCR test on arrival at the Dubai airports and self-isolate until they receive their negative results.

"If passengers opt to take the PCR test on arrival in Dubai, they must self-isolate until test results are received. If the test result is negative, passengers can leave the hotel and enjoy the trip as normal. However, if the test result is positive, passengers are asked to follow the advice of the Dubai Health Authority and self-isolate," Emirates said in a statement.

Budget carrier flydubai said if a passenger tests positive for Covid-19, he/she would need to observe a 14-day quarantine. The airline also advised passengers to comply with all the precautionary Covid-19 measures in place in Dubai "including wearing a mask, observing social distancing and washing your hands regularly".

Tourists with Covid-19 symptoms

* If a traveller is suspected to have Covid-19 symptoms, Dubai Airports has the right to re-test to ensure the tourist is free of the virus

*It is mandatory for Covid-positive tourists to isolate themselves at an institutional facility provided by the government for 14 days at their own expense.

Other requirements

*Travel insurance: Tourists must have a travel insurance with Covid-19 cover or declare that they would bear the costs for treatment and isolation if required. "Bring an insurance certificate stating Covid-19 coverage to present at check-in," Emirates said.

*Visa: Referring to visa requirements, Emirates said: "Depending on your nationality you can get a visa on arrival, or you can apply for your visit visa from Dubai Immigration before you travel."

*Health Declaration Form: Tourists need to complete the form that states they are free from Covid-19 symptoms. This must be done before embarking.

*Tracing app: Tourists must download the Covid-19 DXB app and register details. "This is critically important since it facilitates easy coordination and communication with the health authorities if tourists experience Covid-19 symptoms," Dubai authorities had said earlier.

Riyadh, Apr 25: Saudi Arabia announced nine deaths and 1,197 new cases of the COVID-19 virus on Saturday.

Of these cases, 120 were recorded in Madinah, 364 in Makkah, 271 in Jeddah, 170 in Riyadh and 43 in Dammam.

The number of people who had recovered from the coronavirus in the Kingdom increased to 2,214 after 165 patients were reported to have recovered.

A total of 136 people have died of the disease in the Kingdom so far.