Permit to kill Namibia black rhino fetches $350,000 in US

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.

Washington/Seoul, Apr 26: A special train possibly belonging to North Korean leader Kim Jong Un was spotted this week at a resort town in the country, according to satellite images reviewed by a Washington-based North Korea monitoring project, amid conflicting reports about Mr. Kim's health and whereabouts.

The monitoring project, 38 North, said in its report on Saturday that the train was parked at the “leadership station” in Wonsan on April 21 and April 23. The station is reserved for the use of the Kim family, it said.

Though the group said it was probably Kim Jong Un's train, Reuters has not been able to confirm that independently, or whether he was in Wonsan.

“The train's presence does not prove the whereabouts of the North Korean leader or indicate anything about his health but it does lend weight to reports that Kim is staying at an elite area on the country's eastern coast,” the report said.

Speculation about Mr. Kim's health first arose due to his absence from the anniversary of the birthday of North Korea's founding father and Mr. Kim's grandfather, Kim Il Sung, on April 15.

North Korea's state media last reported on Mr. Kim's whereabouts when he presided over a meeting on April 11.

China has dispatched a team to North Korea including medical experts to advise on Kim Jong Un, according to three people familiar with the situation.

A third-generation hereditary leader who came to power after his father's death in 2011, Kim has no clear successor in a nuclear-armed country, which could present major international risk.

On Thursday, U.S. President Donald Trump downplayed reports that Mr. Kim was ill. “I think the report was incorrect,” Mr. Trump told reporters, but he declined to say if he had been in touch with North Korean officials.

Mr. Trump has met Mr. Kim three times in an attempt to persuade him to give up a nuclear weapons program that threatens the United States as well as its Asian neighbors. While talks have stalled, Mr. Trump has continued to hail Mr. Kim as a friend.

Reporting from inside North Korea is notoriously difficult because of tight controls on information.

A Trump administration official said continuing days of North Korean media silence on Mr. Kim's whereabouts had heightened concerns about his condition, and that information remained scant from a country U.S. intelligence has long regarded as a ”black box.”

The U.S. State Department did not immediately respond to questions about the situation on Saturday.

Daily NK, a Seoul-based website that reports on North Korea, cited one unnamed source in North Korea on Monday as saying that Kim had undergone medical treatment in the resort county of Hyangsan north of the capital Pyongyang.

It said that Mr. Kim was recovering after undergoing a cardiovascular procedure on April 12.

Since then, multiple South Korean media reports have cited unnamed sources this week saying that Mr. Kim might be staying in the Wonsan area.

On Friday, local news agency Newsis cited South Korean intelligence sources as reporting that a special train for Mr. Kim's use had been seen in Wonsan, while Mr. Kim's private plane remained in Pyongyang.

Newsis reported Mr. Kim may be sheltering from COVID-19, the respiratory disease caused by the novel coronavirus.

Mr. Kim, believed to be 36, has disappeared from coverage in North Korean state media before. In 2014, he vanished for more than a month and North Korean state TV later showed him walking with a limp.

Speculation about his health has been fanned by his heavy smoking, apparent weight gain since taking power and family history of cardiovascular problems.

Hundreds of thousands of people across the world are joining the anti-racism demonstrations days after the killing of George Floyd in United Sates. 

The protests are being held in cities including London, Manchester, Cardiff, Leicester and Sheffield.

Demonstrators attached ropes to the statue of Edward Colston before pulling it down to cheers and roars of approval from the crowd. Images on social media show the statue was eventually rolled into the city's harbour. 

It was not the only statue targeted on Sunday. In Brussels, protesters clambered onto the statue of former King Leopold II and chanted "reparations".

The word "shame" was also graffitied on the monument, reference perhaps to the fact that Leopold is said to have reigned over the mass death of 10 million Congolese.

In London, thousands of people congregated around the US embassy for the second day running.

While protests were mainly peaceful, there were some scuffles near the office of Prime Minister Boris Johnson and outside the Parliament gates.

In Hong Kong, about 20 people staged a rally in solidarity with the Black Lives Matter movement on Sunday outside the US consulate in the semi-autonomous Chinese city.

"It's a global issue," Quinland Anderson, a 28-year-old British citizen living in Hong Kong, told The Associated Press news agency.

"We have to remind ourselves despite all we see going on in the US and in the other parts of the world, Black lives do indeed matter."

Several dozen demonstrators took part in a Black Lives Matter protest held in Tel Aviv's central Rabin Square.

A rally in Rome's sprawling People's Square was noisy but peaceful, with the majority of protesters wearing masks to protect against coronavirus. Participants listened to speeches and held up handmade placards saying "Black Lives Matter" and "It's a White Problem".

In Spain, several thousand people gathered on the streets of Barcelona and at the US embassy in Madrid.

Many in Madrid carried homemade signs reading "Black Lives Matter", "Human rights for all" and "Silence is pro-racist".

"We are not only doing this for our brother George Floyd," said Thimbo Samb, a spokesman for the group that organised the events in Spain mainly through social media. "Here in Europe, in Spain, where we live, we work, we sleep and pay taxes, we also suffer racism."