12 shot dead at French satirical weekly

New York, Jan 10: The US's National Transportation Safety Board (NTSB) announced that it has accepted an invitation from Tehran to participate in its investigation into the crash of a Ukrainian plane amid speculations that an Iranian missile might have brought down the plane.

The federal agency said in a statement on Thursday that the Iran Civil Aviation Organization has notified them that they could take part in the investigation of the plane crash that occurred shortly after taking off from Tehran on Wednesday, killing all 176 people on board, reports the Efe news.

"The NTSB has designated an accredited representative to the investigation of the crash," said the independent US government agency tasked with investigating transport accidents.

Since the aircraft was a US-made Boeing 737-800, international regulations allow Washington to be a part of the accident investigation.

However, it remains unclear to what extent the NTSB representative will be able to play an active role in the probe, as US sanctions complicate cooperation with Iran, and the two countries have no diplomatic relations.

The NTSB announcement came hours after US intelligence sources told several media outlets that the Kiev-bound Ukrainian International Airlines (UIA) flight 752 could have been accidentally shot down by an Iranian missile.

Canadian Prime Minister Justin Trudeau later confirmed that his government had "evidence" indicating that the aircraft "was shot down by an Iranian surface to air missile", although he added it may have been unintentional.

The accident occurred on the same day after Iran launched more than a dozen ballistic missiles at two US military bases in Iraq, in retaliation for the killing of Iranian Major General Qasem Soleimani in an American drone attack in Baghdad on January 3.

However, the Iranian authorities have denied that they had accidentally shot down the plane and claimed the accusations were a part of a psychological warfare campaign against Tehran.

Iranian foreign ministry spokesman Abbas Mousavi said they welcomed the presence of experts from countries whose citizens have died in the tragic accident, and requested Trudeau and any other government to provide any information they had regarding the crash.

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 D.C., April 21: North Korea's leader, Kim Jong Un, is in grave danger following a surgery this month, according to a US intelligence official with direct knowledge.

Kim recently missed the celebration of his grandfather's birthday on April 15, which raised speculation about his well-being. He had been seen four days before that at a government meeting, according to intelligence reports cited by CNN.

The National Security Council and Office of the Director of National Intelligence have however declined to comment on the matter.

CNN has also reached out to the CIA and the State Department for comment and sought comment from the South Koreans.

Kim's absences from official state media often spark speculation and rumors about his health. North Korea has no free press and is often a black hole when it comes to the country's leadership. Analysts are heavily reliant on scanning state media dispatches and watching propaganda videos for any semblance of a clue.

Kim last appeared in North Korean state media on April 11. April 15 -- North Korea's most important holiday, the anniversary of the birth of the country's founding father, Kim Il Sung -- came and went without any official mention of Kim Jong Un's movements.

Experts are unsure of what to make of Kim's absence from any festivities celebrating his grandfather. When North Korean leaders have not shown up to these important celebrations in the past, it has portended major developments. But it has also turned out to be nothing.

"There have been a number of recent rumours about Kim's health (smoking, heart, and brain). If Kim is hospitalized, it would explain why he wasn't present on the important April 15th celebrations," said Bruce Klingner, a senior research fellow at the Heritage Foundation and former CIA deputy division chief for North Korea. "But, over the years, there have been a number of false health rumors about Kim Jong-un or his father. We'll have to wait and see."

Kim Jong Il's absence from a parade celebrating North Korea's 60th anniversary in 2008 was followed by rumblings that he was in poor health. It was later revealed he had a stroke, after which his health continued to decline until his death in 2011.

Kim Jong Un disappeared from the public eye for more than a month in 2014, which also prompted speculation about his health. He returned sporting a cane, and days later South Korean intelligence said that he had a cyst removed from his ankle.