NASA probe beams back ultraviolet images of Martian atmosphere

October 18, 2016

Washington, Oct 18: In a first, NASA's MAVEN spacecraft has beamed back ultraviolet images of Mars that unveils dynamic, previously invisible activities in the atmosphere of the red planet such as change in ozone levels over the seasons and formation of clouds.master

The images were taken by the Imaging UltraViolet Spectrograph (IUVS) on the Mars Atmosphere and Volatile Evolution mission (MAVEN) - a space probe designed to study the Martian atmosphere while orbiting Mars.

These were then used to make this movie of rapid cloud formation on Mars on July this year.

The movie uses four MAVEN images to show about seven hours of Mars rotation during this period, and interleaves simulated views that would be seen between the four images.

"MAVEN obtained hundreds of such images in recent months, giving some of the best high-resolution ultraviolet coverage of Mars ever obtained," said Nick Schneider from the University of Colorado, Boulder in the US.

Nightside images show ultraviolet (UV) "nightglow" emission from nitric oxide (NO). Nightglow is a common planetary phenomenon in which the sky faintly glows in the complete absence of external light.

Mars' nightside atmosphere emits light in the ultraviolet due to chemical reactions that start on Mars' dayside.

Ultraviolet light from the Sun breaks down molecules of carbon dioxide and nitrogen, and the resulting atoms are carried around the planet by high-altitude wind patterns that encircle the planet.

On the nightside, these winds bring the atoms down to lower altitudes where nitrogen and oxygen atoms collide to form nitric oxide molecules. The recombination releases extra energy, which comes out as ultraviolet light.

Scientists predicted NO nightglow at Mars, and prior missions detected its presence, but MAVEN has returned the first images of this phenomenon in the Martian atmosphere.

Splotches and streaks appearing in the images occur where NO recombination is enhanced by winds.

Such concentrations are clear evidence of strong irregularities in Mars' high altitude winds and circulation patterns. These winds control how Mars' atmosphere responds to its very strong seasonal cycles.

Dayside images show the atmosphere and surface near Mars' south pole in unprecedented ultraviolet detail. They were obtained as spring comes to the southern hemisphere.

Ozone is destroyed when water vapour is present, so ozone accumulates in the winter polar region where the water vapour has frozen out of the atmosphere.

The images show ozone lasting into spring, indicating that global winds are inhibiting the spread of water vapour from the rest of the planet into winter polar regions.

MAVEN observations also show afternoon cloud formation over the four giant volcanoes on Mars.
Clouds are a key to understanding a planet's energy balance and water vapour inventory, so these observations will be valuable in understanding the daily and seasonal behaviour of the atmosphere, researchers said.

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Agencies
March 15,2020

Houston, Mar 15: Researchers, studying the novel coronavirus, have found that the time between cases in a chain of transmission is less than a week, and over 10 per cent of patients are infected by someone who has the virus, but does not show symptoms yet, a finding that may help public health officials contain the pandemic.

The study, published in the journal Emerging Infectious Diseases, estimated what's called the serial interval of the coronavirus by measuring the time it takes for symptoms to appear in two people with the virus -- the person who infects another, and the infected second person.

According to the researchers, including those from the University of Texas at Austin, the average serial interval for the novel coronavirus in China was approximately four days.

They said the speed of an epidemic depends on two things -- how many people each case infects, and how long it takes cases to spread.

The first quantity, the scientists said, is called the reproduction number, and the second is the serial interval.

Due to the short serial interval of the disease caused by the coronavirus -- COVID-19 -- they said, emerging outbreaks will grow quickly, and could be difficult to stop.

“Ebola, with a serial interval of several weeks, is much easier to contain than influenza, with a serial interval of only a few days,” said Lauren Ancel Meyers, study co-author from UT Austin.

Meyers explained that public health responders to Ebola outbreaks have much more time to identify and isolate cases before they infect others.

“The data suggest that this coronavirus may spread like the flu. That means we need to move quickly and aggressively to curb the emerging threat,” Meyers added.

In the study, the scientists examined more than 450 infection case reports from 93 cities in China, and found the strongest evidence yet that people without symptoms must be transmitting the virus -- known as pre-symptomatic transmission.

More than one in ten infections were from people who had the virus but did not yet feel sick, the scientists said.

While researchers across the globe had some uncertainty until now about asymptomatic transmission with the coronavirus, the new evidence could provide guidance to public health officials on how to contain the spread of the disease.

“This provides evidence that extensive control measures including isolation, quarantine, school closures, travel restrictions and cancellation of mass gatherings may be warranted,” Meyers said.

The researchers cautioned that asymptomatic transmission makes containment more difficult.

With hundreds of new cases emerging around the world every day, the scientists said, the data may offer a different picture over time.

They said infection case reports are based on people's memories of where they went and whom they had contact with, and if health officials move quickly to isolate patients, that may also skew the data.

“Our findings are corroborated by instances of silent transmission and rising case counts in hundreds of cities worldwide. This tells us that COVID-19 outbreaks can be elusive and require extreme measures,” Meyers said.

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Agencies
January 4,2020

Stockholm, Jan 4: “I’m not the kind of person who celebrates birthdays,” Greta Thunberg said as she turned 17 on Friday, marking the occasion in inimitable style - with a seven-hour hour protest outside the Swedish parliament.

The climate activist braved winter conditions in her native Stockholm to continue the weekly Friday School Strike for the Climate campaign that helped catapult her to international fame.

“I stand here striking from 8am until 3pm as usual ... then I’ll go home,” Thunberg, Time magazine’s Person of the Year for 2019, told Reuters.

“I won’t have a birthday cake but we’ll have a dinner.”

It’s been a busy 12 months for Thunberg, who crisscrossed the globe by car, train and boat - but not plane - to demand action on climate change.

“It has been a strange and busy year, but also a great one because I have found something I want to do with my life and what I am doing is having an impact,” she said.

When she was 15, Thunberg began skipping school on Fridays to demonstrate outside the Swedish parliament to push her government to curb carbon emissions. Her campaign gave rise to a grassroots movement that has gone global, inspiring millions of people to take action.

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News Network
May 7,2020

Islamabad, May 7: Pakistan's COVID-19 cases have crossed 24,000 after 1,523 new infections were detected, while the death toll has jumped to 564 with 38 more people succumbing to the coronavirus, health officials said on Thursday.

Even as the country is seeing an increase in the number of coronavirus cases and fatalities, Prime Minister Imran Khan will discuss the easing of lockdown restrictions with his top aides on Thursday.

The Ministry of National Health Services said that out of the 24,073 total cases, Punjab reported 9,077, Sindh 8,640, Khyber-Pakhtunkhwa 3,712, Balochistan 1,495, Islamabad 521, Gilgit-Baltistan 388 and Pakistan-occupied Kashmir 76 cases.

After 38 more deaths on Wednesday, the total coronavirus patient death toll jumped to 564. Another 6,464 have recovered. A total of 1,523 new patients were added in a single day, the ministry.

So far, 244,778 tests have been conducted, including 12,196 in the last 24 hours, it said.

Prime Minister Khan will chair the National Coordination Committee (NCC) meeting on easing the lockdown restrictions in the country. The meeting will be attended by all chief ministers.

The issue was debated in the National Command and Operation Centre (NCOC) on Wednesday and in the Cabinet on Tuesday.

Planning Minister Asad Umar said that different proposals to allow certain businesses to open were prepared and will be presented before the Prime Minister for a final decision.

Earlier, Khan, undeterred by the mounting number of deaths and the new cases, announced that he was against a lockdown as it hits the poor people badly.

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