US man tries to burn store run by Indian-Americans in Florida

New Delhi, Jan 3: US aviation regulator Federal Aviation Administration on Thursday warned America's airlines and their pilots that there is risk involved in operating flights in Pakistan airspace due to "extremist or militant activity", according to an official document.

"Exercise caution during flight operations. There is a risk to US civil aviation operating in the territory and airspace of Pakistan due to extremist/militant activity," said the US Federal Aviation Administration (FAA) in a notice to airmen (NOTAM) dated December 30, 2019.

The NOTAM is applicable to all US-based airlines and US-based pilots.

The US regulator said in its NOTAM that there continues to be a risk to US civil aviation sector from attacks against airports and aircraft in Pakistan, particularly for aircraft on the ground and aircraft operating at low altitudes, including during the arrival and departure phases of flights.

"The ongoing presence of extremist/militant elements operating in Pakistan poses a continued risk to US civil aviation from small-arms fire, complex attacks against airports, indirect weapons fire, and anti-aircraft fire, any of which could occur with little or no warning," it said.

The FAA said that while, to date, there have been no reports of man-portable air defense systems or Manpads being used against the civil aviation sector in Pakistan, some extremist or terrorist groups operating there are suspected of having access to these Manpads.

"As a result, there is potential risk for extremists/militants to target civil aviation in Pakistan with Manpads," it said.

The regulator added that pilots or airlines must report safety or security incidents - which may happen in Pakistan - to the FAA.

Pakistan on July 16 last year opened its airspace for India after about five months of restrictions imposed in the wake of a standoff with New Delhi.

Following the Balakot airstrikes by the Indian Air Force, Pakistan had closed its airspace on February 26 last year.

Pakistan in October last year had denied India's request to allow Prime Minister Narendra Modi's VVIP flight to use its airspace for his visit to Saudi Arabia over the Jammu and Kashmir issue.

Washington, Jul 14: The United States has the biggest Covid-19 testing programme in the world, better than big countries like Russia, China, India and Brazil, President Donald Trump said on Monday, asserting that America has "just about the lowest mortality rate" due to the disease in the world.

"We have one of the lowest mortality rates anywhere," Trump said at a White House roundtable. More than 34 lakh Americans have tested positive for Covid-19 so far and over 1,37,000 have died due to the disease, both of which are the largest numbers among all the countries.

The huge number of positive cases, the president said, is due to the massive testing efforts undertaken by his administration, more extensive than any other country.

"We test more than anybody by far. And when you test, you create cases. So we have created cases. I can tell you that some countries, they test when somebody walks into a hospital sick or walks into maybe a doctor's office, but usually a hospital. That is the testing they do, so they do not have cases, whereas we have all these cases. So, it is a double-edged sword," he said.

At the same time, the United States has the lowest mortality rate or just about the lowest mortality rate due to the disease in the world, Trump added. "We are doing a great job. We are doing very well with vaccines and we are doing very, very well with therapeutics. I think we are going to have some very good information coming out soon," he said in response to a question.

"But we have the best and certainly, by far, the biggest testing programme anywhere in the world. If you tested China or Russia or any of the larger countries, if you just tested India, as an example, the way we test, you would see numbers that would be very surprising. Brazil too. You know, Brazil is going through a big problem, but they do not do testing like we do," Trump said.

"So we do the testing and by doing the testing, we have tremendous numbers of cases. As an example, we have done 45 million tests. If we did half that number, you would have half the cases probably -- around that number. If we did another half of that, you would have half the numbers. Everyone would be saying, 'Oh, we are doing so well on cases'," he added.

Responding to a question, Trump said what China did to the world should not be forgotten.

"I think what China has done to the world with what took place -- the China plague -- you can call it the China virus, you can call it whatever you want to call it. It has about 20 different names. What they did to the world should not be forgotten," he said.

The trade deal with China that was signed early this year remains intact, the president said. "It is intact, they (China) are buying. Whether they buy or not, that is up to them. They are buying," he said.

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.