Sri Lanka releases 18 Indian fishermen

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.

Saint Martin's Island, Feb 12: At least 15 women and children drowned and more than 50 others were missing after a boat overloaded with Rohingya refugees sank off southern Bangladesh as it tried to reach Malaysia Tuesday, officials said.

Some 138 people -- mainly women and children -- were packed on a trawler barely 13 metres (40 feet) long, trying to cross the Bay of Bengal, a coast guard spokesman told news agency.

"It sank because of overloading. The boat was meant to carry maximum 50 people. The boat was also loaded with some cargo," another coast guard spokesman, Hamidul Islam, added.

Nearly one million Rohingya live in squalid camps near Bangladesh's border with Myanmar, many fleeing the neighbouring country after a 2017 brutal military crackdown.

With few opportunities for jobs and education in the camps, thousands have tried to reach other countries like Malaysia and Thailand by attempting the hazardous 2,000-kilometre journey.

In the latest incident, 71 people have been rescued including 46 women. Among the dead, 11 were women and the rest children.

Anwara Begum said two of her sons, aged six and seven, drowned in the tragedy.

"We were four of us in the boat... Another child (son, aged 10) is very sick," the 40-year-old told news agency.

Fishermen tipped off the coast guard after they saw survivors swimming and crying for help in the sea.

The boat's keel hit undersea coral in shallow water off Saint Martin's Island, Bangladesh's southernmost territory, before it sank, survivors said.

"We swam in the sea before boats came and rescued us," said survivor Mohammad Hossain, 20.

Coast guard commander Sohel Rana said three survivors, including a Bangladeshi, were detained over human trafficking allegations.

An estimated 25,000 Rohingya left Bangladesh and Myanmar on boats in 2015 trying to get to Thailand, Malaysia and Indonesia. Hundreds drowned when overloaded boats sank.

Begum said her family paid a Bangladeshi trafficker $450 per head to be taken to Malaysia.

"We're first taken to a hill where we stayed for five days. Then they used three small trawlers to take us to a large trawler, which sank," she said.

Shakirul Islam, a migration expert whose group works with Rohingya to raise awareness against trafficking, said desperation in the camps was making refugees want to leave.

"It was a tragedy waiting to happen," he said.

"They just want to get out, and fall victim to traffickers who are very active in the camps."

Islam said in the past two months dozens of Rohingya reported approaches from traffickers to his OKUP migration rights group.

"Human smuggling and trafficking in the Bay of Bengal is particularly difficult to address as it requires concerted effort from multiple states," the Bangladesh head of UN agency the International Organization for Migration, Giorgi Gigauri, told news agency.

"The gaps in coordination are easily exploited by criminal networks."

Since last year, Bangladeshi authorities have picked up over 500 Rohingya from rickety fishing trawlers or coastal villages as they waited to board boats.

Trafficking often increases during the November-March period when the sea is safest for the small trawlers used by traffickers.

Bangladesh and Myanmar signed a repatriation deal to send back some Rohingya to their homeland, but none have agreed to return because of safety fears.

The charity Save the Children called on Myanmar to "take all necessary steps to ensure the Rohingya community can return to their homes in a safe and dignified manner".

"The tragic drowning of women and children... should be a wake-up call for us all," the group's Athena Rayburn said in a statement.

Beijing/Wuhan, Apr 17: China's coronavirus death toll mounted to 4,632 on Friday as the country revised figures in its epicentre Wuhan with 1,290 additional fatalities amid international criticism of under-reporting of COVID-19 data.

The Wuhan municipal headquarters on Friday revised the number of confirmed COVID-19 cases and deaths due to the disease, state-run Xinhua news agency reported.

As of April 16, the total number of confirmed coronavirus cases in Wuhan was increased by 325 to 50,333 and the number of fatalities up by 1,290 to 3,869.

The revised figure raised China's overall COVID-19 death toll to 4,632. The total number of cases also increased to 82,692.

The Wuhan municipal headquarters in a notification said the revisions were made in accordance with related laws and regulations as well as the principle of being responsible for history, the people and the deceased.

The revision of figures came amid sharp criticism of China by the US and other nations for its alleged under-reporting of the coronavirus cases and cover-up of the origin of the viral strain, which emerged in Wuhan in December last, reportedly from the local Hunan sea food market.

Explaining the reason for the figure revision, the Wuhan municipality said it was done to ensure that the information on the city's COVID-19 epidemic is open and transparent, and that the data are accurate.

Listing the reasons for the data discrepancies, it said the surging number of patients at the early stage of the epidemic overwhelmed medical resources and the admission capacity of medical institutions. Some patients died at home without having been treated in hospitals.

Besides, during the height of their treating efforts, hospitals were operating beyond their capacities and medical staff were preoccupied with saving and treating patients, resulting in belated, missed and mistaken reporting.

Also, due to a rapid increase of designated hospitals for treating COVID-19 patients -- including those administered by ministries, Hubei Province, Wuhan city and its districts, those affiliated to companies, as well as private hospitals and makeshift hospitals -- a few medical institutions were not linked to the epidemic information network and failed to report their data in time.

The registered information of some of the deceased patients was incomplete, and there were repetitions and mistakes in the reporting, the Wuhan authorities noted.

Citing an official of the Wuhan municipal headquarters, Xinhua reported that a group for epidemic-related big data and epidemiological investigations was established in late March.

The group used information from online systems and collected full information from all epidemic-related locations to ensure that facts about every case are accurate and every figure is objective and correct.

"What lie behind the epidemic data are the lives and health of the general public, as well as the credibility of the government," the official was quoted by the report.

The timely revision of the figures, among other things, shows respect for every single life, the official said.

Meanwhile, the revised cases were not included in the overall national figures released by China's National Commission (NHC) in its daily report on Friday as it reports previous day's cases.

As per NHC data, as of Thursday the overall confirmed cases of coronavirus was 82,367, including 3,342 deaths.

As many as 1,081 patients are being treated and 77,944 people discharged after recovery, it said.

NHC said it received reports of 26 new confirmed COVID-19 cases from the mainland on Thursday, of which 15 were imported.

The other 11 new cases were domestically transmitted, it said, noting that five cases were reported in Guangdong Province, three in Heilongjiang Province, two in Shandong Province and one in Liaoning Province.

No death was reported on Thursday on the mainland.

As of Thursday, China has a total of 1,549 imported cases, NHC said, adding that 879 were undergoing treatment with 45 in severe condition. Besides, there were 66 new asymptomatic cases, taking the tally to 1,038.