Harsha Moily: Progressive political leadership, communal harmony must for development of Dakshina Kannada

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of the American Medical Association, noted that the the current guidelines issued by the WHO and CDC are based on outdated models from the 1930s of how gas clouds from a cough, sneeze, or exhalation spread.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

Bengaluru, Jul 7: There seems no impact of Covid-19 on kharif crop sowing in Karnataka with the current year actually being ahead of previous years, according to an official here on Monday.

"In agriculture, as far as sowing is concerned, there is no impact of COVID-19," Agriculture Commissioner Brijesh Kumar Dikshit told IANS. One of the reasons, according to Dikshit, is that people in rural areas are aware, but not scared of the pandemic.

"In rural India, coronavirus is there. People are aware, not scared. They are taking precautions, but don't have any phobia," he said.

Another reason was that by June the number of infections in Karnataka was not as high as other states, when a lot of sowing was done, he said.

By the end of June, Karnataka saw 15,242 Covid-19 cases. Of that, 7,074 were active.

The sowing is ahead of previous year as it's mostly dependent on weather. "It's ahead of previous years. Agriculture is directed by weather and rains had been slightly earlier this year," he said.

According to Karnataka State Natural Disaster Monitoring Centre, at 185 mm the state received 14 mm less rain in June against the normal 199 mm. "It's like a normal year, or slightly a good year," he said.

Some crops will be sown in the last fortnight of July and few more will extend up to August 15. "The last two weeks will be critical and on July 31 we should be able to tell whether we are short or ahead," he said.

According to preliminary indications, the Commissioner said the area under agriculture is increasing this year, which could also be because that labourers might have come back.