Congress failed as Opposition, disconnected with people: Modi

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.

New Delhi, Feb 6: Unemployment rate in the country as per a new survey was 6.1 per cent in 2017-18, the government informed Rajya Sabha on Wednesday.

Minister of State for Labour Santosh Gangwar said the government is conducting a new Periodic Labour Force Survey (PLFS) with new parameters and bigger sample size, and its results cannot be compared with previous surveys in this regard.

"As per the new Periodic Labour Force Survey being conducted by the government, the labour force participation is 36.9 per cent and the rate of unemployment for 2017-18 is 6.1 per cent," he said.

Replying to supplementaries during the Question Hour, the minister said the report of this survey is very different than the surveys conducted in previous years.

This survey is not comparable to previous surveys, he said, adding it was an attempt to provide authentic data with the new survey conducted through the Ministry of Statistics.

"We are focusing on infrastructure development and ease of doing business and India's position in the world has improved. India has improved its position to 63rd rank now in 2019 against 196 in previous years," he said.

"Our government is very conscious of creating employment opportunities and is running such programme which generates employment.

"The way our government is functioning, employment opportunities are being created and the youths are getting jobs also," the minister said.

Gangwar said the government has stopped the previous survey as the sample size was low and an attempt is being made to improve the data by adding various parameters and provide more authentic data.

The minister said it will take time for collection of data as households have to be visited on the ground for authentic data collection in rural areas also.