Ex-PM Sharif leaves Pakistan for medical treatment in London

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.

New Delhi, Jan 3: US aviation regulator Federal Aviation Administration on Thursday warned America's airlines and their pilots that there is risk involved in operating flights in Pakistan airspace due to "extremist or militant activity", according to an official document.

"Exercise caution during flight operations. There is a risk to US civil aviation operating in the territory and airspace of Pakistan due to extremist/militant activity," said the US Federal Aviation Administration (FAA) in a notice to airmen (NOTAM) dated December 30, 2019.

The NOTAM is applicable to all US-based airlines and US-based pilots.

The US regulator said in its NOTAM that there continues to be a risk to US civil aviation sector from attacks against airports and aircraft in Pakistan, particularly for aircraft on the ground and aircraft operating at low altitudes, including during the arrival and departure phases of flights.

"The ongoing presence of extremist/militant elements operating in Pakistan poses a continued risk to US civil aviation from small-arms fire, complex attacks against airports, indirect weapons fire, and anti-aircraft fire, any of which could occur with little or no warning," it said.

The FAA said that while, to date, there have been no reports of man-portable air defense systems or Manpads being used against the civil aviation sector in Pakistan, some extremist or terrorist groups operating there are suspected of having access to these Manpads.

"As a result, there is potential risk for extremists/militants to target civil aviation in Pakistan with Manpads," it said.

The regulator added that pilots or airlines must report safety or security incidents - which may happen in Pakistan - to the FAA.

Pakistan on July 16 last year opened its airspace for India after about five months of restrictions imposed in the wake of a standoff with New Delhi.

Following the Balakot airstrikes by the Indian Air Force, Pakistan had closed its airspace on February 26 last year.

Pakistan in October last year had denied India's request to allow Prime Minister Narendra Modi's VVIP flight to use its airspace for his visit to Saudi Arabia over the Jammu and Kashmir issue.

Scientists predict the world may have a COVID-19 vaccine within one year or even a few months earlier, said the Director-General of the World Health Organisation even as he underlined the importance of global cooperation to develop, manufacture and distribute vaccines.

However, making the vaccine available and distributing it to all will be a challenge and requires political will, Tedros Adhanom Ghebreyesus said on Thursday during a meeting with the European Parliament's Committee for Environment, Public Health and Food Safety.

One option would be to give the vaccine only to those that are most vulnerable to the virus.

There are currently over 100 COVID-19 vaccine candidates in various stages of development.

Adhanom Ghebreyesus said the pandemic has highlighted the importance of global solidarity and that health should not be seen as a cost but an investment.

He added that all countries in the world must strengthen primary health care and crisis preparedness and stressed the need for EU leadership globally.

While the Director-General said the situation in the EU has improved significantly, he underlined that COVID-19 is very much still circulating globally, with more than four million new cases in the last month.

Many Members of European Parliament said that the global community must cooperate including in developing, manufacturing and distributing vaccines against COVID-19 and asked when a safe vaccine could be available.

Several Members of European Parliament underlined the importance of the WHO but also said it has made mistakes in its response to the pandemic.

The Director-General admitted everyone makes mistakes and informed the members that an independent panel will evaluate the WHO response to the pandemic to learn from any mistakes made.

It will start its work soon, he said.