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Vision deterioration in astronauts likely owing to lack of a day-night cycle in intracranial pressure: Scientists

Vision deterioration in astronauts is likely owing to the lack of a day-night cycle in intracranial pressure, say scientists

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Mars plans to send a manned mission to mars by 2030, Pixabay
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New York, Jan 19, 2017: Vision deterioration in astronauts is likely owing to the lack of a day-night cycle in intracranial pressure, say scientists, adding that using a vacuum device to lower pressure for part of each day might prevent the problem.

To study how zero-gravity conditions affect intracranial pressure, researchers from University of Texas Southwestern Medical Centre recruited volunteer patients who had had a port permanently placed in their head as part of treatment for cancer.

The ports provided a way for researchers to measure intracranial pressure.

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NASA flights then flew the eight volunteers one by one on steep up-and-down maneuvers (parabolic flights) that created 20-second intervals of weightlessness.

The researchers measured intracranial pressure during the zero-gravity intervals and compared these with intracranial pressure during standard times of sitting, lying face upward (supine), and lying with head inclined downward.

The findings showed that intracranial pressure in zero-gravity conditions, such as exists in space, is higher than when people are standing or sitting on Earth, but lower than when people are sleeping on Earth.

“These challenging experiments were among the most ambitious human studies ever attempted and changed the way we think about the effect of gravity – and its absence – on pressure inside the brain,” said senior author Dr Benjamin Levine, Professor of Internal Medicine.

It suggests that the constancy of pressure on the back of the eye causes the vision problems astronauts experience over time.

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“The information from these studies is already leading to novel partnerships with companies to develop tools to simulate the upright posture in space while astronauts sleep, thereby normalising the circadian variability in intracranial pressure,” added Dr Levine.

“The idea is that the astronauts would wear negative pressure clothing or a negative pressure device while they sleep, creating lower intracranial pressure for part of each 24 hours,” noted first author Dr Justin Lawley in a paper appeared in the Journal of Physiology. (IANS)

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Scientists spot massive ice deposits on Mars

Recent observations by MRO's ground-penetrating Shallow Radar instrument revealed a buried ice layer that covers more ground than the state of New Mexico.

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Scientists found layers of ice on the surface of Mars. Wikimedia Commons
  • Recently, scientists have found layers of ice on the Martian land.
  • Scientists think this ice might be a useful source of water for future humans.
  • The researchers had researched 8 locations on the surface of Mars.

Scientists have unearthed thick and massive deposits of ice in some regions on Mars.

The images taken by the High-Resolution Imaging Science Experiment (HiRISE) camera aboard NASA’s Mars Reconnaissance Orbiter (MRO) showed the three-dimensional structure of massive ice deposits on Mars.

The ice sheets extend from just below the surface to a depth of 100 meters or more and appear to contain distinct layers.

It extending downward from depths as shallow as 1 to 2 meters below the surface, which could preserve a record of Mars’ past climate, the researchers noted in the journal Science.

This ice which was found can help scientists understand the climate history of Mars. IANS
This ice which was found can help scientists understand the climate history of Mars. IANS

“We expect the vertical structure of Martian ice-rich deposits to preserve a record of ice deposition and past climate,” said Colin M. Dundas, from the US Geological Survey.

“They might even be a useful source of water for future human exploration of the red planet,” Dundas added.

The researchers investigated eight locations on Mars and found thick deposits cover broad regions of the Martian mid-latitudes with a smooth mantle.

However, erosion in these regions creates scarps that expose the internal structure of the mantle.

The scarps are actively retreating because of sublimation of the exposed water ice.

The layers of ice can be used as water source by future humans on Mars, VOA
The layers of ice can be used as water source by future humans on Mars, VOA

The ice deposits likely originated as snowfall during Mars’ high-obliquity periods and have now compacted into massive, fractured, and layered ice.

Previous researchers have revealed that the Red Planet harbours subsurface water ice.

Recent observations by MRO’s ground-penetrating Shallow Radar instrument revealed a buried ice layer that covers more ground than the state of New Mexico.

NASA’s Phoenix lander had also dug up some ice near the Martian north pole in 2008, however, it is not clear if that is part of the big sheet. IANS