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
May 26,2020

UN, May 26: Countries could see a "second peak" of coronavirus cases during the first wave of the pandemic if lockdown restrictions were lifted too soon, the World Health Organization (WHO) has warned.

Mike Ryan, the WHO's head of emergencies, told a briefing on Monday that the world was "right in the middle of the first wave", the BBC reported.

He said because the disease was "still on the way up", countries need to be aware that "the disease can jump up at any time".

"We cannot make assumptions that just because the disease is on the way down now that it's going to keep going down," Ryan said.

There would be a number of months to prepare for a second peak, he added.

The stark warning comes as countries around the world start to gradually ease lockdown restrictions, allowing shops to reopen and larger groups of people to gather.

Experts have said that without a vaccine to give people immunity, infections could increase again when social-distancing measures are relaxed.

Ryan said countries where cases are declining should be using this time to develop effective trace-and-test regimes to "ensure that we continue on a downwards trajectory and we don't have an immediate second peak".

Also on Monday, Tedros Adhanom Ghebreyesus, WHO Director-General, said that a clinical trial of hydroxychloroquine (HCQ) on COVID-19 patients has come to "a temporary pause", while the safety data of the the anti-malaria drug was being reviewed.

According to the WHO chief, The Lancet medical journal on May 22 had published an observational study on HCQ and chloroquine and its effects on COVID-19 patients that have been hospitalized, reports Xinhua news agency.

The authors of the study reported that among patients receiving the drug, when used alone or with a macrolide, they estimated a higher mortality rate.

"The Executive Group of the Solidarity Trial, representing 10 of the participating countries, met on Saturday (May 23) and has agreed to review a comprehensive analysis and critical appraisal of all evidence available globally," Tedros said in a virtual press conference.

The developments come as the total number of global COVID-19 cases has increased to 5,508,904, with 346,508 deaths, according to the Johns Hopkins University.

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News Network
May 11,2020

Kabul, May 11: Four back-to-back roadside bombs exploded in a northern district of Afghanistan's capital Kabul on Monday, wounding four civilians including a child, police said. Kabul police spokesman Ferdaws Faramarz said a clearance team was at the site of the attacks.

Militants have carried out several roadside bombings and rocket attacks in Kabul and other parts of the country in recent weeks, but Monday's four consecutive explosions appeared to be the first coordinated effort for some months.

The Taliban has not carried out any large attacks in the city since they signed a landmark withdrawal deal with the US in February, meant to pave the way for peace in the country. No group has claimed the attacks. The explosions come as authorities are trying to impose a lockdown in the capital to curb the spread of coronavirus in the country.

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Agencies
July 15,2020

Washington, Jul 15: The Trump administration has agreed to rescind its July 6 rule, which temporarily barred international students from staying in the United States unless they attend at least one in-person course, a federal district court judge said on Tuesday.

The U-turn by the Trump administration comes following a nationwide outrage against its July 6 order and a series of lawsuits filed by a large number of educational institutions, led by the prestigious Harvard University and Massachusetts Institute of Technology (MIT), seeking a permanent injunctive relief to bar the Department of Homeland Security (DHS) and the US Immigration and Customs Enforcement (ICE) from enforcing the federal guidelines barring international students attending colleges and universities offering only online courses from staying in the country.

As many as 17 US states and the District of Columbia, along with top American IT companies such as Google, Facebook and Microsoft, joined MIT and Harvard in the US District Court in Massachusetts against the DHS and the ICE in seeking an injunction to stop the entire rule from going into effect.

"I have been informed by the parties that they have come to a resolution. They will return to the status quo," Judge Allison Burroughs, the federal district judge in Boston, said in a surprise statement at the top of the hearing on the lawsuit.

The announcement comes as a big relief to international students, including those from India. In the 2018-2019 academic year, there were over 10 lakh international students in the US. According to a recent report of the Student and Exchange Visitor Program (SEVP), 1,94,556 Indian students were enrolled in various academic institutions in the US in January.

Judge Burroughs said the policy would apply nationwide.

"Both the policy directive and the frequently asked questions would not be enforced anyplace," she said, referring to the agreement between the US government and MIT and Harvard.

Congressman Brad Scneider said this is a great win for international students, colleges and common sense.

"The Administration needs to give us a plan to tackle our public health crisis - it can't be recklessly creating rules one day and rescinding them the next," he said in a tweet.

Last week, more than 136 Congressmen and 30 senators wrote to the Trump administration to rescind its order on international students.

"This is a major victory for the students, organisers and institutions of higher education in the #MA7 and all across the country that stood up and fought back against this racist and xenophobic rule," said Congresswoman Ayanna Pressley.

"Taking online classes shouldn't force international students out of our country," Congressman Mikie Sherrill said in a tweet.

In its July 6 notice, the ICE had said all student visa holders, whose university curricula were only offered online, "must depart the country or take other measures, such as transferring to a school with in-person instruction to remain in lawful status".

"If not, they may face immigration consequences, including but not limited to the initiation of removal proceedings," it had said.

In their lawsuit, the 17 states and the District of Columbia said for many international students, remote learning in the countries and communities they come from would impede their studies or be simply impossible.

The lawsuit alleged that the new rule imposes a significant economic harm by precluding thousands of international students from coming to and residing in the US and finding employment in fields such as science, technology, biotechnology, healthcare, business and finance, and education, and contributing to the overall economy.

In a separate filing, companies like Google, Facebook and Microsoft, along with the US Chamber of Commerce and other IT advocacy groups, asserted that the July 6 ICE directive will disrupt their recruiting plans, making it impossible to bring on board international students that businesses, including the amici, had planned to hire, and disturb the recruiting process on which the firms have relied on to identify and train their future employees.

The July 6 directive will make it impossible for a large number of international students to participate in the CPT and OPT programmes. The US will "nonsensically be sending...these graduates away to work for our global competitors and compete against us...instead of capitalising on the investment in their education here in the US", they said.

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