4 Indian doctors want to return home from Ebola-hit Nigeria

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.

Huawei will be completely removed from the UK's 5G networks by the end of 2027, the UK government announced on Tuesday after a review by the country's National Cyber Security Centre (NCSC) on the impact of US sanctions against the Chinese telecommunications giant.

In the lead up to this complete removal of all Huawei kit from UK networks, there will be a total ban on the purchase of any new 5G kit after December 31, 2020.

The decision was taken at a meeting of the UK's National Security Council (NSC) chaired by Prime Minister Boris Johnson, in response to new US sanctions against the telecom major imposed in May which removed the firm's access to products which have been built based on US semiconductor technology.

5G will be transformative for our country, but only if we have confidence in the security and resilience of the infrastructure it is built upon, said Oliver Dowden, UK Secretary of State for Digital, Culture, Media and Sport (DCMS).

Following US sanctions against Huawei and updated technical advice from our cyber experts, the government has decided it necessary to ban Huawei from our 5G networks. No new kit is to be added from January 2021, and UK 5G networks will be Huawei free by the end of 2027. This decisive move provides the industry with the clarity and certainty it needs to get on with delivering 5G across the UK, he said.

The minister, who laid out the details of the UK's ban on Huawei in the House of Commons, said the government will now seek to legislate with a new Telecoms Security Bill to put in place the powers necessary to implement the tough new telecoms security framework.

By the time of the next election (2024) we will have implemented in law an irreversible path for the complete removal of Huawei equipment from our 5G networks, said Dowden.

The new law will give the government the national security powers to impose these new controls on high risk vendors and create extensive security duties on network operators to drive up standards, DCMS said.

Technical experts at the NCSC reviewed the consequences of the US sanctions and concluded that Huawei will need to do a major reconfiguration of its supply chain as it will no longer have access to the technology on which it currently relies and there are no alternatives which we have sufficient confidence in.

They found the new restrictions make it impossible to continue to guarantee the security of Huawei equipment in the future.

After a ban on the purchase of new Huawei kit for 5G from next year, the aim is to completely remove the Chinese vendor's influence on 5G networks across the UK by the end of 2027.

The DCMS said Tuesday's decision takes into account the UK's specific national circumstances and how the risks from these sanctions are manifested in the country.

The existing restrictions on Huawei in sensitive and critical parts of the network remain in place, it highlighted.

The DCMS said the US action also affects Huawei products used in the UK's full fibre broadband networks. However, the UK has managed Huawei's presence in the UK's fixed access networks since 2005 and we also need to avoid a situation where broadband operators are reliant on a single supplier for their equipment.

As a result, following security advice from experts, DCMS is advising full fibre operators to transition away from purchasing new Huawei equipment. A technical consultation will determine the transition timetable, but it is expect this period to last no longer than two years.

The government said its new approach strikes the right balance by recognising full fibre's established presence and supporting the connections that the public relies on, while fully addressing the security concerns.

It stressed that its new policy in relation to high risk vendors has not been designed around one company, one country or one threat but as an enduring and flexible policy that will enable the UK to manage the risks to the network, now and in the future.

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.