War can't solve Kashmir issue; 2 nuclear-armed countries won’t fight: Imran Khan

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, May 9: The Trinamool Congress on Saturday responded to Union home minister Amit Shah’s charge that the Mamata Banerjee-led West Bengal government is not facilitating the movement of stranded migrant workers.

Amit Shah has written to West Bengal chief minister Mamata Banerjee, saying her government is doing “injustice” to migrant workers by not allowing the special Shramik trains to reach the state.

“Union home minister Amit Shah speaks after weeks of silence only to mislead people with lies,” the TMC’s Abhishek Banerjee was quoted as saying by news agency PTI.

“The Centre is lying… West Bengal is running 711 camps for migrants in the state. We are taking good care of them,” Abhishek Banerjee, who is also the chief minister’s nephew, said.

Amit Shah had pointed out in his letter that the Centre was not receiving the “expected support” from the state government in helping stranded migrant workers from West Bengal.

“West Bengal government is not allowing trains with migrants reaching the state. This is injustice with WB migrant labourers. This will create further hardship for them,” Amit Shah had said in his letter to Mamata Banerjee.

The issue of migrant workers is the latest flashpoint between the Centre and the West Bengal government amid a row over the state’s efforts to control the coronavirus disease (Covid-19).

The Centre and the state have exchanged allegations over the criteria for reporting deaths from the infection, and while While Bengal says the Centre is trying to politicise a public health crisis, the Union government maintains that state officials are ignoring repeated warnings to step up the fight against the disease.

Federal officials have said that the region has not conducted adequate tests and that there has been mismanagement over identifying hotspots and containing them.

Union home secretary Ajay Bhalla also slammed the state government for a very low rate of testing and high rate of mortality, 13.2%, by far the highest for any state.

The Centre has also accused the state government of not allowing cross-border movement of goods trucks to Bangladesh.

There are 1,678 Covid-19 cases and 160 deaths in West Bengal until Saturday morning.

Karachi, May 23: Ninety-seven people were killed and two survived when a passenger plane crashed into homes in Pakistan's southern city of Karachi, health officials said Saturday.

The Pakistan International Airlines (PIA) plane had made multiple approaches to land at the city's airport when it came down in a residential area, damaging buildings and sparking a rescue operation that lasted into the night.

All passengers and crew had been accounted for and the bodies of those killed had been recovered from the crash site, the Sindh Health Ministry said, adding that 19 had been identified.

A local hospital earlier reported it had received the bodies of people killed on the ground.

The site remained cordoned off on Saturday morning.

The crash sent plumes of smoke were into the air as rescue workers and residents searched the debris for people and as firefighters tried to extinguish the flames.

An AFP reporter witnessed charred bodies being loaded into ambulances.

PIA said the plane lost contact with air traffic control just after 2:30 pm (0930 GMT) travelling from Lahore to Karachi.

The disaster comes as Pakistanis prepare to celebrate the end of Ramadan and the beginning of Eid al-Fitr, with many travelling back to their homes in cities and villages.