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The current physical distancing guidelines provided by the World Health Organisation (WHO) and by the US Centers for Disease Control and Prevention (CDC) may not be adequate to curb the coronavirus spread, according to a research which says the gas cloud from a cough or sneeze may help virus particles travel up to 8 metres. The research, published in the Journal of the American Medical Association, noted that the the current guidelines issued by the WHO and CDC are based on outdated models from the 1930s of how gas clouds from a cough, sneeze, or exhalation spread.

Study author, MIT associate professor Lydia Bourouiba, warned that droplets of all sizes can travel 23 to 27 feet, or 7-8 metres, carrying the pathogen.

According to Bourouiba, the current guidelines are based on "arbitrary" assumptions of droplet size, "overly simplified", and "may limit the effectiveness of the proposed interventions" against the deadly pandemic.

 She explained that the old guidelines assume droplets to be one of two categories, small or large, taking short-range semi-ballistic trajectories when a person exhales, coughs, or sneezes.

However based on more recent discoveries, the MIT scientist said, sneezes and coughs are made of a puff cloud that carries ambient air, transporting within it clusters of droplets of a wide range of sizes.

Bourouiba warned that this puff cloud, with ambient air entrapped in it, can offer the droplets moisture and warmth that can prevent it from evaporation in the outer environment.

"The locally moist and warm atmosphere within the turbulent gas cloud allows the contained droplets to evade evaporation for much longer than occurs with isolated droplets," she said.

"Under these conditions, the lifetime of a droplet could be considerably extended by a factor of up to 1000, from a fraction of a second to minutes," the researcher explained in the study.

The MIT scientist, who has researched the dynamics of coughs and sneezes for years, added that these droplets settle along the trajectory of a cough or sneeze contaminating surfaces, with their residues staying suspended in the air for hours.

"Even when maximum containment policies were enforced, the rapid international spread of COVID-19 suggests that using arbitrary droplet size cutoffs may not accurately reflect what actually occurs with respiratory emissions, possibly contributing to the ineffectiveness of some procedures used to limit the spread of respiratory disease," Bourouiba wrote in the study

Thrissur, Feb 11: The latest test result of the woman medical student, who arrived here from China's Wuhan region and was the first positive case from India for the novel Coronavirus (nCoV), has come out negative, health officials said on Monday.

Her condition was "stable", they said.

According to the state health department as of now, 31 people are in isolation wards across various hospitals in the state.

"The blood test result of the first patient from Thrissur, from the National Institute of Virology (NIV) testing centre at Alappuzha, shows a negative result.

But we need confirmation from the NIV at Pune," a senior medical officer told news agency.

After the first positive case was reported from Thrissur, two other Keralite students from Wuhan, the epicentre of the virus, had tested positive in Alappuzha and Kasaragod districts.

The health department had earlier said those in isolation wards of various hospitals in the state have come down to 34.

"A total of 3,367 are under observation across the state, of which 3,336 are under home quarantine," a release issued by the health department said.

The department has already sent at least 364 samples for testing at the NIV at Pune and so far 337 results have returned negative.

The ''state calamity'' alert, which was declared on February 3, was withdrawn on Friday after no new positive cases of infection were detected.

Tumkur, Jun 2: Karnataka Agriculture Minister BC Patil on Monday said that state will not be affected due to locust swarm as it has moved to other states.

"There will be no effect as locust insects diverted to other states after they came from Pakistan. We were also worried and were prepared to face it, luckily we will not be affected by insects," he said.

Locust is a type of grasshoppers and moves in large numbers and devastates crops. Several parts of Rajasthan including Ganganagar have reported locust attacks.

There is a prediction of another attack in June this year.