Taliban attack prison in Pakistan, free militants

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.

Beijing, Jun 16: The coronavirus situation in China's capital is "extremely severe", a city official warned Tuesday, as 27 new infections were reported from Beijing where a new cluster has sparked a huge trace-and-test programme.

The COVID-19 resurgence -- believed to have started at the sprawling Xinfadi wholesale food market in the capital -- has sparked alarm as China had largely brought its outbreak under control through mass testing and lockdowns imposed earlier in the year.

The new cases took the number of confirmed infections in Beijing over the past five days to 106, as authorities locked down almost 30 communities in the city and tested tens of thousands of people.

"The epidemic situation in the capital is extremely severe," Beijing city spokesman Xu Hejian warned at a press conference.

The World Health Organization had already expressed concern about the cluster, pointing to Beijing's size and connectivity.

Officials in the capital have said they will test stall owners and managers at all of the city's food markets, restaurants and government canteens.

Beijing's coronavirus testing capacity has been expanded to 90,000 a day, according to China's official news agency Xinhua.

On Tuesday, the capital's transport commission banned taxi- and ride-hailing services from driving out of the city, Xinhua reported, in another move to try and contain the new outbreak.

All indoor sports and entertainment venues in Beijing were ordered to shut on Monday, and some other cities across China warned they would quarantine those arriving from the capital.

The National Health Commission also reported four new domestic infections in Hebei province, which surrounds Beijing, and a case reported in southwestern Sichuan province was linked to the Beijing cluster.

Authorities were also racing to track people from Beijing who had travelled to other parts of China, and those who visited the capital have been encouraged to get tested.

Beijing spokesman Xu said: "High-risk people who have left Beijing must inform local authorities immediately."

Market inspections

Authorities shut down another market on Tuesday -- Tiantaohonglian in the central Xicheng district -- after one employee there was diagnosed with COVID-19, state broadcaster CCTV reported.

Seven residential estates surrounding that market were also locked down.

In total, Beijing officials said Tuesday they have disinfected 276 agricultural markets, closed 11 markets, and disinfected more than 33,000 food and beverage businesses in a bid to stamp out the new cluster.

Officials had warned Sunday that since May 30, 200,000 people had visited the Xinfadi market -- the original site of the new outbreak.

More than 8,000 workers from Xinfadi have been tested and sent to centralised quarantine facilities.

Until this recent outbreak, most of China's cases in recent months were nationals returning home as the pandemic spread to other countries.

China's Center for Disease Control and Prevention said Monday that the virus strain found in the Beijing outbreak was a "major epidemic strain in the European countries".

While the virus was detected on chopping boards used to handle imported salmon at Xinfadi, "it does not clearly or definitely indicate it's from imported seafood", Wu Zunyou, the body's chief epidemiologist, said in an interview with state broadcaster CCTV.

"Ever since new cases suddenly emerged in Beijing, we have tried to figure out the reasons for the outbreak since there were no COVID-19 cases found over the past two months," Wu Zunyou said.

"We came up with several possibilities, and the most likely one is that the carrier of the novel coronavirus comes from outside China or other parts of China and brought it here."

On Tuesday, another eight imported cases were reported.

Naypyitaw, Jul 2: A landslide at a jade mine in northern Myanmar has killed at least 113 people, officials say, warning the death toll is likely to rise further.

The incident took place early on Thursday in the jade-rich Hpakant area of Kachin state after a bout of heavy rainfall, the Myanmar Fire Services Department said on Facebook.

"The jade miners were smothered by a wave of mud," the statement said. "A total of 113 bodies have been found so far," it added, raising the death toll from at least 50.

Photos posted on the Facebook page showed a search and rescue team wading through a valley apparently flooded by the mudslide.

'No one could help them'

Maung Khaing, a 38-year-old miner from the area, said he saw a towering pile of waste that looked on the verge of collapse and was about to take a picture when people began shouting "run, run!"

"Within a minute, all the people at the bottom [of the hill] just disappeared," he told Reuters news agency by phone.

"I feel empty in my heart. I still have goosebumps ... There were people stuck in the mud shouting for help, but no one could help them."

Tar Lin Maung, a local official with the information ministry, said authorities had recovered more than 100 bodies.

"Other bodies are in the mud. The numbers are going to rise," he told Reuters.

Fatal landslides are common in the poorly regulated mines of Hpakant, the victims often from impoverished communities who risk their lives hunting the translucent green gemstone.

The government of Myanmar leader Aung San Suu Kyi pledged to clean up the industry when it took power in 2016, but activists say little has changed.

Official sales of jade in Myanmar were worth $750.4m in 2016-2017, according to data published by the government as part of the Extractive Industries Transparency Initiative.

But experts believe the true value of the industry, which mainly exports to China, is much larger.

Northern Myanmar's abundant natural resources - including jade, timber, gold and amber - have also helped finance both sides of a decades-long conflict between ethnic Kachin and the military.

The fight to control the mines and the revenues they bring frequently traps local civilians in the middle.