141 feared buried in landslide in Sichuan's Maoxian

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.

Melbourne, July 1: Authorities will lock down around 300,000 people in suburbs north of Melbourne for a month from late on Wednesday to contain the risk of infection after two weeks of double-digit rises in new coronavirus cases in Australia's second-most populous state.

Australia has fared better than many countries in the pandemic, with around 7,830 cases and 104 deaths, but the recent surge has stoked fears of a second wave of COVID-19, echoing concerns expressed in other countries.

Globally, coronavirus cases exceeded 10 million on Sunday, a major milestone in the spread of a disease that has killed more than half a million people in seven months.

From midnight, more than 30 suburbs in Australia's second-biggest city will return to stage three restrictions, the third-strictest level in curbs to control the pandemic. That means residents will be confined to home except for grocery shopping, health appointments, work or caregiving, and exercise.

The restrictions will be accompanied by a testing blitz that authorities hope will extend to half the population of the area affected, and for which borders will be patrolled, authorities said. The measures come as curbs ease across the rest of the state of Victoria, with restaurants, gyms and cinemas reopening in recent weeks.

Victoria recorded 73 fresh cases on Tuesday from 20,682 tests, following an increase of 75 cases on Monday. State premier Daniel Andrews warned on Wednesday that the return of broader restrictions across city remained a possibility.

"If we all stick together these next four weeks, we can regain control of that community transmission ... across metropolitan Melbourne," Andrews said at a briefing. "Ultimately if I didn't shut down those postcodes I'd be shutting down all postcodes. We want to avoid that."

Victoria's spike in cases has been linked to staff members at hotels housing returned travellers for which quarantine protocols were not strictly followed. Victorian state authorities have announced an investigation into the matter.

Some other Australian states and territories are preparing to open borders, but applying limits and quarantine measures to citizens of Victoria as the school holiday season gets under way.

South Australia, the country's fifth most populous state, has had just three new cases in the past month. But citing the spike in coronavirus infections, on Tuesday it cancelled its scheduled reopening to other parts of the nation.

New South Wales (NSW), Australia's most populous state, has stopped short of closing its borders to all Victorians, but those holidaying from hotspot areas - not permitted under NSW rules - can be handed a fine of A$11,000 ($7,596) or jailed if they are detected, state authorities said.

The delays reopening internal borders cast doubts over a federal plan to set up "travel bubble" with neighbouring New Zealand that would allow movement between the two countries.

Washington, Feb 19: US President Donald Trump has said he is "saving the big deal" with India for later and he "does not know" if it will be done before the presidential election in November, clearly indicating that a major bilateral trade deal during his visit to Delhi next week might not be on the cards.

"We can have a trade deal with India. But I'm really saving the big deal for later," he told reporters at Joint Base Andrews Tuesday afternoon (local time).

The US and India could sign a "trade package" during the visit, according to media reports.

Asked whether he expects a trade deal with India before the visit, Trump said, "We're doing a very big trade deal with India. We'll have it. I don't know if it'll be done before the election, but we'll have a very big deal with India."

US Trade Representative Robert Lighthizer, the point-person for trade negotiations with India, is likely to not accompany Trump to India, sources said. However, officials have not ruled it out altogether.

In an apparent dissatisfaction over US-India trade ties, Trump said, "We're not treated very well by India." But he praised Prime Minister Narendra Modi and said he is looking forward to his visit to India.

"I happen to like Prime Minister Modi a lot," Trump said.

"He told me we'll have seven million people between the airport and the event. And the stadium, I understand, is sort of semi under construction, but it's going to be the largest stadium in the world. So it's going to be very exciting... I hope you all enjoy it," he told reporters.

Meanwhile, the US-India Strategic and Partnership Forum (USISPF) in a report said the latest quarterly data depict continuation of overall positive bilateral trade trends. The third quarter data reflects some downslide in growth rates.

"It may be due to several reasons, including the unexpected economic slowdown in India's economic growth, impact of US-China trade war, GSP withdrawal from the US side and retaliatory tariffs on specific US goods from the Indian side," USISPF said.

According to the report, the data available for the first three quarters of 2019 (January-September) pulled the overall growth rate in cumulative bilateral trade down to 4.5 percent from 8.4 percent registered for the first two quarters.

Goods and services trade performance in third quarter was dismal at -2.3 percent, in contrast with the impressive 9.6 percent growth witnessed for the first two quarters of the year; while trade in services was up two percent goods trade dropped five percent, the report said.

The cumulative US-India trade in goods and services (USD 110.9 billion) for the first three quarters of 2019 increased 4.5 percent with US exports and imports growing at four percent and five percent respectively.

The US exported USD 45.3 billion worth of goods and services to India in the first three quarters 2019, up 4 percent from the corresponding period in the previous year; and the US imported USD 65.6 billion worth of goods and services from India, up five percent from the previous year's USD 62.5 billion level for the same period, it said.

The USISPF has projected that the total bilateral trade can touch USD 238 billion by 2025 if the current 7.5 percent average annual rate of growth sustains; however, higher growth rates can result in bilateral trade in the range of USD 283 billion and USD 327 billion.

The US remains the top trading partner for India in terms of trade in goods and services, followed by China. While the bilateral trade between US and India is approximately 62 percent in goods and 38 percent in services, the bilateral trade between India and China is dominated by goods.

China had a huge trade surplus of USD 58 billion with India, indicating Beijing's strength in the Indian market, especially in sectors, such as electronics, machinery, organic chemicals, plastics and medical devices.

The US goods exports to India, in comparison, were mainly concentrated in mineral fuels, precious stones, and aircraft. The US faces tough competition with China in the Indian market in areas such as electronics, machinery, organic chemicals and medical devices.