Facebook removes 1.5 million horrific videos of New Zealand terror attack

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, May 25: China has reported 51 new coronavirus cases including 40 asymptomatic infections, majority of them in the contagion's first epicentre Wuhan, where over six million tests have been conducted in the last 10 days, health officials said on Monday.

The country's National Health Commission (NHC) said that 11 new imported cases were reported on Sunday.

While no new domestically-transmitted COVID-19 cases were reported in China on Sunday, 11 imported cases including 10 in the Inner Mongolia Autonomous Region and one in Sichuan province were reported, the NHC said in its daily report.

Out of the 40 new asymptomatic cases, 38 were reported in Wuhan, which is currently undergoing mass testing of its over 11.2 million people after a spike in the asymptomatic cases.

Currently, 396 people with asymptomatic symptoms are under medical observation in China, including 326 in Wuhan, according to the health authority.

Asymptomatic cases refer to the patients who have tested COVID-19 positive but develop no symptoms such as fever, cough or sore throat. However, they pose a risk of spreading the disease to others.

Wuhan, which earlier had over 50,000 cases between January and March, started a campaign on May 14 to expand the nucleic acid testing in order to better know the number of asymptomatic cases or people who show no clear symptoms despite carrying the virus.

According to the latest figures released by the Wuhan municipal health commission, the city conducted more than 6 million nucleic acid tests between May 14 and 23.

On Saturday, the city carried out nearly 1.15 million tests, state-run Xinhua news agency reported on Monday.

Nucleic acid testing is a molecular technique for screening blood donations to reduce the risk of transfusion transmitted infections.

As of Sunday, a total of 82,985 confirmed COVID-19 cases have been reported in China with 4,634 fatalities, the NHC added.

Wuhan, Apr 15: In the six days after top Chinese officials secretly determined they likely were facing a pandemic from a new coronavirus, the city of Wuhan at the epicenter of the disease hosted a mass banquet for tens of thousands of people; millions began traveling through for Lunar New Year celebrations.

President Xi Jinping warned the public on the seventh day, Janaury 20. But by that time, more than 3,000 people had been infected during almost a week of public silence, according to internal documents obtained by The Associated Press and expert estimates based on retrospective infection data.

That delay from Jan 14 to Jan. 20 was neither the first mistake made by Chinese officials at all levels in confronting the outbreak, nor the longest lag, as governments around the world have dragged their feet for weeks and even months in addressing the virus.

But the delay by the first country to face the new coronavirus came at a critical time — the beginning of the outbreak. China's attempt to walk a line between alerting the public and avoiding panic set the stage for a pandemic that has infected almost 2 million people and taken more than 126,000 lives.

A This is tremendous, a said Zuo-Feng Zhang, an epidemiologist at the University of California, Los Angeles. If they took action six days earlier, there would have been much fewer patients and medical facilities would have been sufficient. We might have avoided the collapse of Wuhan's medical system.

Other experts noted that the Chinese government may have waited on warning the public to stave off hysteria, and that it did act quickly in private during that time.

But the six-day delay by China's leaders in Beijing came on top of almost two weeks during which the national Center for Disease Control did not register any cases from local officials, internal bulletins obtained by the AP confirm. Yet during that time, from Jan 5 to Jan 17, hundreds of patients were appearing in hospitals not just in Wuhan but across the country.

It's uncertain whether it was local officials who failed to report cases or national officials who failed to record them. It's also not clear exactly what officials knew at the time in Wuhan, which only opened back up last week with restrictions after its quarantine.

But what is clear, experts say, is that China's rigid controls on information, bureaucratic hurdles and a reluctance to send bad news up the chain of command muffled early warnings. The punishment of eight doctors for rumor-mongering, broadcast on national television on Jan. 2, sent a chill through the city's hospitals.

Doctors in Wuhan were afraid, said Dali Yang, a professor of Chinese politics at the University of Chicago. It was truly intimidation of an entire profession. Without these internal reports, it took the first case outside China, in Thailand on Jan 13, to galvanize leaders in Beijing into recognising the possible pandemic before them. It was only then that they launched a nationwide plan to find cases distributing CDC-sanctioned test kits, easing the criteria for confirming cases and ordering health officials to screen patients, all without telling the public.

The Chinese government has repeatedly denied suppressing information in the early days, saying it immediately reported the outbreak to the World Health Organization.

Allegations of a cover-up or lack of transparency in China are groundless, said foreign ministry spokesman Zhao Lijian at a Thursday press conference.

The documents show that the head of China's National Health Commission, Ma Xiaowei, laid out a grim assessment of the situation on Jan. 14 in a confidential teleconference with provincial health officials.

A memo states that the teleconference was held to convey instructions on the coronavirus from President Xi Jinping, Premier Li Keqiang and Vice Premier Sun Chunlan, but does not specify what those instructions were.

The epidemic situation is still severe and complex, the most severe challenge since SARS in 2003, and is likely to develop into a major public health event, the memo cites Ma as saying.

The National Health Commission is the top medical agency in the country. In a faxed statement, the Commission said it had organised the teleconference because of the case reported in Thailand and the possibility of the virus spreading during New Year travel. It added that China had published information on the outbreak in an open, transparent, responsible and timely manner," in accordance with important instructions repeatedly issued by President Xi.

The documents come from an anonymous source in the medical field who did not want to be named for fear of retribution. The AP confirmed the contents with two other sources in public health familiar with the teleconference. Some of the memo's contents also appeared in a public notice about the teleconference, stripped of key details and published in February.

Under a section titled sober understanding of the situation, the memo said that clustered cases suggest that human-to-human transmission is possible. It singled out the case in Thailand, saying that the situation had changed significantly because of the possible spread of the virus abroad.

With the coming of the Spring Festival, many people will be traveling, and the risk of transmission and spread is high, the memo continued.