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What is the secret behind the giant gravity hole in the Indian Ocean called the geoid depression? | Science



What is the secret behind the giant gravity hole in the Indian Ocean called the geoid depression?  |  Science

Researchers have determined the origin of the giant geoid depression by modeling how tectonic plates slid over Earth’s hot, sticky mantle over the past 140 million years.

Beneath the Indian Ocean lies a giant gravity well, estimated to be about 3 million square kilometers in size, where the ocean floor sinks into a vast depression, where the gravitational forces are greatly weakened.

Oceanographic surveys and satellite measurements have revealed that sea level falls near the tip of the Indian subcontinent due to the difference in gravity between points of gravity and surrounding gravity wells, called geologic lows under the Indian Ocean. .”

Plate grave

And I tried Many studies The explanation for tectonic subsidence under the Indian Ocean is that it is caused by remnants of a previous plate sinking into the Earth’s crust under another plate millions of years ago. However, there is no definitive explanation.

Other researchers have used seismic waves to image the Earth’s interior in three dimensions to study mantle convection as material sinks down.

They found that the lighter material in the upper and middle mantle below the geoid accounts for the low gravity in this region. Most current theories have tried to explain this anomaly in the lower geoid with the help of dense, cold oceanic plates that sank into the mantle in the past.

In 2018, a team of scientists from India’s National Center for Polar and Ocean Research – on board a ship – set out to map the geoid trough and distribute a series of seismic measurements on the sea floor in the target area.

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The team was able to track hot flows of molten rock rising beneath the Indian Ocean. Of course, it is necessary to look for a scenario that explains the formation of a geoid depression in its early stages.

Origins and Determinants

According to A statement Published on the “Science Alert” website (Science Alert) researchers have determined the origin of the giant geoid depression by modeling how tectonic plates slid over Earth’s hot and viscous mantle over the past 140 million years.

During that period, the Indian tectonic plate broke away from the supercontinent Gondwana and began its march northward. As the Indian plate separated, the ancient Tethys sea floor sank into the mantle and the Indian Ocean opened up.

And inside study Published last May in the journal Geophysical Research Letters, geologists Dipanjan Pal and Adri Ghosh of the Indian Institute of Science’s Center for Geology in Bangalore said, “Previous studies have all studied gravitational deformation within the geoid depression, but they haven’t been concerned with how he grew up.”

Researchers believe the answer lies more than a thousand kilometers beneath the Earth’s crust, where the cold and dense remnants of an ancient ocean sank into a “plate grave” beneath Africa about 30 million years ago, moving hotly. Rock magma. The researchers believe that the lighter material at the top of the middle part of the mantle is responsible for the weakening of gravity in this region.

The giant gravity hole is estimated to be about 3 million square kilometers (International Center for Global Earth Models).

Hot magma flow

To reach these conclusions, Paul and Ghosh used more than 10 computer models to simulate the motion of the plates and the motion of the mantle, and compared the pattern of oceanic subsidence predicted by those models to observations documented from geoid depressions. .

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The two researchers worked with ten samples — which they hypothesized were flows of low-density hot magma rising from beneath the geoid depression. This geoid depression, in addition to the structuring role of the mantle layer, is formed by buoyant flows to a sufficient height.

“Our results suggest that the outflow must be buoyant enough to ascend to mid-depth to match the existing geoid depression in terms of shape and height,” the researchers wrote.

The paper said the first flows from these thermal layers originated about 20 million years ago south of the geologic low in the Indian Ocean, and about 10 million years after the ancient Tethys Sea sank into the lower mantle. The tectonic subsidence increased as the flows spread beneath the crust and approached peninsular India.

Because the findings are consistent with elements of Gauche’s previous modeling work in 2017, the geologist duo suggested that the flows appeared after the ancient Mediterranean-Tethys sea floor sank into the lower mantle, disrupting the famed “Africa block.”

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Home Covid-19 tests are valid for detecting new strains



Home Covid-19 tests are valid for detecting new strains

Director of the Clinical Virology Laboratory at the American Mayo Clinic, Dr. Matthew Pinker answers frequently asked questions about the expiration dates of home testing kits for “Covid-19” and their ability to detect new strains of the virus.

Home tests

* Validity of test instruments. At-home Covid-19 tests allow you to collect your own sample and detect active Covid-19 infection. But what if you have expired or outdated Covid-19 test kits at home in your cupboard?

Dr. Matthew Pinker says: Companies arbitrarily plan original test kits; Because the development of these at-home diagnostic tests was rapid. Therefore; Check your tools before throwing them away.

“Now three and a half years into the epidemic, these manufacturers have had the opportunity to evaluate the effectiveness of the test over a longer period of time,” Dr. Pinker adds. “In many cases the expiration dates have been updated.”

Home Covid Test (Shutterstock)

Recommendations on accuracy of tests

-If you have test kits at home, search the US Food and Drug Administration (FDA) website for updated expiration dates.

– “If you take a test after the expiration date and the test is positive, this is a reliable result, especially if you have a respiratory disease.

If you get a negative result from a test that’s past the expiration date, “I recommend making sure the test doesn’t have an extended expiration date.” Beyond that, you should get another test or ask your healthcare provider to collect a swab for lab testing before ruling you (Covid-19) free,” says Dr. Beneker.

Tracking current “corona” strains

* Can home tests detect current strains of “Covid-19”?

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– Yes, it should detect currently circulating covid-19 strains. The good news is that most of the changes to the virus within these new variants are in the spike protein, the part of the virus that attaches to cells.

“The protein that the antigen tests are looking for is a different protein where there aren’t many mutations,” says Dr. Pinker. “This allows us to say with confidence that these tests should pick up cyclic strains.”

Test results

*If the test comes back positive (confirmed), are you contagious? What if you test positive for coronavirus (Covid-19)?

Often, Dr. Benniker says, “when the home antigen test is positive, it means that this person is still secreting large amounts of viral protein.” “In most cases, that means the person is excreting that amount of virus, and it can be a large amount of virus that can spread from one person to another.” If you get a positive result, he adds. Antigen testing at home Consider risk of viral transmission. If the result is positive, you may be infected with Covid-19.

*But what if you develop symptoms and test negative?

“If you test negative at home and are still experiencing common symptoms of Covid-19, such as a sore throat, cough, fever and body aches, I recommend that you visit your healthcare provider and get tested.” Dr. Pinker says. This is because “the collected swab can be sent to the laboratory and tested based on the polymerase chain reaction. This will give us more reliable information about whether you are actually infected with (Covid-19) or not.

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When is the test done?

* When should you get tested for “COVID-19”?

Testing is recommended in some situations, Dr. Pinker says. Such as:

. Symptoms appear. If you develop symptoms such as fever, cough, sore throat, runny nose or body aches.

. If you spend time with someone who has been confirmed to have the coronavirus (COVID-19).

. If you plan to visit someone who is at risk of serious illness. This includes someone with cancer, the elderly, or anyone taking medications that suppress their immune system. If you’re infected with the virus, don’t get yourself tested right away, Dr. Pinker says. “My advice is to wait a few days and not go straight home and get tested; This is because the virus does not have enough time to reach levels that would cause antigen tests to be positive. “Usually, I wait three days after that.”

. Exposure, then testing. If the result is negative, consider another test the next day or 48 hours later; Generally, by the fifth day after exposure, if you test negative within that time frame, you can clear the virus.

Atmospheric temperature and accuracy of tests

* Home temperature and “Covid-19” testsSince temperatures fluctuate greatly in geographic regions, would these tests be affected by hot or cold temperatures?

Information packages accompanying at-home antigen tests should provide information on storage conditions set by the Food and Drug Administration, Dr. Pinker says. Here is a good read. “If you live in an area that experiences subzero weather, such as during the summer months, or temperatures above 100 degrees F (37.8 C), it’s always a good idea to check the package that comes with the test for acceptable storage conditions.

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* “Mayo Clinic News Network” – “Tribune Media” Services

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Why not keep your toothbrush in the bathroom?



Why not keep your toothbrush in the bathroom?


We all know that maintaining oral hygiene is very important and the most important step to do this is to brush your teeth twice a day with mouthwash and floss.

But according to experts, you could be putting your oral hygiene at risk by storing your toothbrush in the bathroom.

“Storing your toothbrush in the bathroom can expose you to a variety of health problems, but the level of risk varies depending on the bathroom environment and your specific habits,” explains Dr. Payal Bhalla, principal dentist and medical director of Quest Dental.

Dr. Balla says that aerosolized bacteria can pose a problem because “when you flush the toilet, especially when the lid is open, small droplets containing bacteria and other microorganisms can splash out and settle on nearby surfaces, including your toothbrush.”

When your toothbrush is near the toilet, it’s “more likely to come into contact with airborne particles and water splashes” that “lead to contamination.”

Bathrooms can also be a humid environment, which can encourage the growth of bacteria and mold on your toothbrush.

In shared bathrooms, “there is a greater potential for cross-contamination as multiple people use the space and touch different surfaces.”

As for faecal particles, which can be on your toothbrush, Dr. Bhalla explains: “It’s possible to have faecal particles in the bathroom environment, including surfaces like your toothbrush. This can happen when toilets are cleaned. Not closing the lid, and brushing can release small droplets of faecal bacteria and other microbes into the air. .To reduce the risk of faecal particles coming into contact with your toothbrush, you can follow hygiene tips such as rinsing your toothbrush before using it, storing it upright, covering it with the toothbrush, and closing the toilet lid when washing.

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She also recommends “rinsing your toothbrush thoroughly under tap water before using it” because it “will help remove any potential contaminants. Also place your toothbrush upright in a toothbrush cup and allow it to air dry. Make sure it doesn’t touch other toothbrushes. ” To prevent cross contamination.

Dr. Bhalla emphasized the importance of changing toothbrushes “every three to four months or so” to keep them healthy and effective.

He added: “To reduce the spread of airborne particles, close the toilet lid before cleaning, use a breathable toothbrush cover to protect your toothbrush from bathroom contaminants, and regularly clean the toothbrush holder or cup to prevent bacteria and mold build-up. “

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The Day of the Big Clash… NASA on Historic Mission to Save Earth (Photos)



The Day of the Big Clash… NASA on Historic Mission to Save Earth (Photos)

02:35 PM

Wednesday, September 20, 2023

Scientists believe that September 24, 2182 marks the date that the asteroid “Bennu” will hit the Earth, so the American space agency NASA is preparing to undertake a dangerous mission to prevent a collision and save our planet from destruction.

According to NASA, this space rock passes close to our planet every 6 years, but it will have a very close encounter with Earth after another 159 years, and if it collides with us, its force will be equal to 22 nuclear bombs.

Although the odds of a cataclysmic impact are estimated at 1 in 2,700, NASA sent a spacecraft to Bennu 7 years ago to collect samples from it. They hope the data will help them prepare for an asteroid deflection mission similar to NASA’s DART mission, which successfully changed the orbit of the small asteroid moon Temorphos last year.

The asteroid samples will reach Earth this week, landing in the Utah desert on September 24.

“We’re now in the final stages of this seven-year mission,” Rich Burns, OSIRIS-REx program manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, told the Sunday Telegraph.

Bennu is about 492 meters wide (about half the size of the asteroid that killed the dinosaurs), so it wasn’t big enough to cause global extinction.

NASA estimated that it could have an impact 9 kilometers wide and cause devastation in a radius of about 1,000 kilometers from the crash site.

Between now and 2300 the chance of Bennu colliding with Earth is 1750.

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“The raw materials from asteroid Bennu will help shed light on how our solar system formed 4.5 billion years ago and how life began on Earth,” said Nicola Fox, associate administrator of NASA’s Science Operations Directorate in Washington.

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