The "water nymph" of the Yucatan Peninsula


The find has been named Naia, Greek for "water nymph".
"Pristine prehistoric skeleton of teenage girl found in underwater cave" : by Sheryl Ubelacker, May 16th, 2014, CTV News,  The pristine skeleton of a teenaged girl who lived about 13,000 years ago, discovered in a deep, water-filled underground cavern in the sprawling cave system in Mexico's Yucatan Peninsula, is providing archeologists with an unprecedented glimpse into the history of the early inhabitants of the Americas. Given the name Naia, Greek for "water nymph," the remains of the 15- or 16-year-old girl were found at the bottom of the boulder-strewn, underwater chamber dubbed Hoyo Negro -- "black hole" in Spanish -- along with the scattered bones of 26 large animal species, among them sabre-tooth tigers, giant ground sloths and cave bears. "Sealed off by water and darkness for over 8,000 years, it is a time capsule of the environment and human life in central America at the end of the Ice Age, when glaciers across the globe trapped massive amounts of water as ice and sea level was far lower than it is today," said American paleontologist Jim Chatters, head of an international research team investigating the site and its archeological treasures. Chatters, the first scientist to study the prehistoric skeleton known as Kennewick Man that was found in Washington state in 1996, described Hoyo Negro as being like a miniature of California's La Brea tar pits, "only without the tar and with considerably better preservation." At the time of Naia's death, the caves would have been dry and accessible, he told a media teleconference. "Perhaps seeking fresh water in the dark passages, animals and at least one human fell into this inescapable ... trap." Naia's remains were discovered in 2007 by three Mexican cave divers exploring an underwater cavern, deep in the Yucatan jungle about eight kilometres from the Caribbean coast. In a 50-metre-deep sinkhole within the cavern, the girl's skull was resting on a boulder, "laying upside-down with a perfect set of teeth and dark eye sockets looking back at us," said diver Alberto Nava. After the divers reported their find to the National Institute of Anthropology and History in Mexico, a consortium of 16 scientists and cave explorers from Mexico, the U.S. and Canada was formed in 2011 to photograph and document the site, and to collect fossilized flora and fauna samples for testing. "A big part of it has just been trying to map the locations of things and get the shape of the tunnels and cavern, and mapping locations of human bones and animal bones," said Ed Reinhardt, a professor of geography and earth sciences at McMaster University in Hamilton who is part of the research team. His role is studying microfossils, such as those of single-celled animals, and water salinity, within Hoyo Negro. But beyond the stunning discovery of Naia's skeletal remains in her watery grave, reported Thursday in the journal Science, is what DNA from her bones is telling researchers about the origins of the Western Hemisphere's first peoples and their link to modern-day native Americans. Based on carbon-dating and other chronology testing, the researchers estimate "the small, slight" girl lived between 12,000 and 13,000 years ago. DNA was extracted from one of Naia's teeth and scientists sequenced what's called mitochondrial DNA, which is passed from mother to child. The results show the girl is related, maternally at least, to today's native Americans, meaning both would trace their lineage to Beringia -- the land masses on either side of the ancient land bridge now covered by the Bering Sea that was used by prehistoric people to migrate from northeast Asia into what is now Alaska and southward into Central and South America. Those first migrants have been dubbed the Clovis people. Whether all early inhabitants of the Americas came across the Bering land bridge or somehow migrated from elsewhere in the world remains a controversial question because of the differences in skull shape and facial features among prehistoric fossilized remains discovered across the Americas and modern-day indigenous populations. Naia's skull shape and facial features are considered "Paleoamerican" and differ from native Americans living today in the Western Hemisphere. "Because she exhibits the distinctive Paleoamerican skull and facial features, the study shows for the first time that Paleoamericans with these distinctive features can have Beringian ancestry," said Deborah Bolnick, a genomic anthropologist at the University of Texas at Austin. Bolnick said the physical differences between them are likely due to evolutionary changes that occurred either in Beringia or in the Americas over the last 9,000 years, rather than the two groups having separate origins. "Mitochondrial DNA for this individual does not exclude the possibility of separate ancestry for some Paleoamericans, but our results provide no evidence for an early migration to the Americas from other regions of the world -- southeast Asia, Australia or Europe -- as some have proposed," she said. "Instead, our results suggest that Paleoamericans and contemporary native Americans both have Beringian ancestry." Reinhardt of McMaster said Hoyo Negro, which is now off-limits to the public because unauthorized divers have disturbed the artifacts, said the cathedral-like site is breathtakingly beautiful, with crystal-clear water surrounded by white limestone walls. But for Naia, who may have been seeking fresh water in the cavern and accidentally plunged into the sinkhole and could find no escape, it must have been a terrifying experience, he said. "When we're diving the site, it's spectacular, but the reality is this pit was a bit of a house of horrors in the sense that you would drop and perhaps survive the fall but not have any light. You wouldn't know the extent of the cavern. You'd be in a pool of water (at the bottom), kind of thrashing around trying to get out. "Yeah, it would have been a pretty awful way to die for sure." Source: Article
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Oceans in Outer Solar System on Pluto and Large Kuiper Belt Objects, Slowly Freezing Over Time


Credit of NASA, ESA, and A. Feild (STScI)
A new study suggests that Pluto and other large Kuiper belt objects started out with liquid oceans which have been slowly freezing over time.

The accretion of new material during Pluto’s formation may have generated enough heat to create a liquid ocean that has persisted beneath an icy crust to the present day, despite the dwarf planet’s orbit far from the sun in the cold outer reaches of the solar system.

This “hot start” scenario, presented in a paper published June 22 in Nature Geoscience, contrasts with the traditional view of Pluto’s origins as a ball of frozen ice and rock in which radioactive decay could have eventually generated enough heat to melt the ice and form a subsurface ocean.

“For a long time people have thought about the thermal evolution of Pluto and the ability of an ocean to survive to the present day,” said coauthor Francis Nimmo, professor of Earth and planetary sciences at UC Santa Cruz. “Now that we have images of Pluto’s surface from NASA’s New Horizons mission, we can compare what we see with the predictions of different thermal evolution models.”

Because water expands when it freezes and contracts when it melts, the hot-start and cold-start scenarios have different implications for the tectonics and resulting surface features of Pluto, explained first author and UCSC graduate student Carver Bierson.

“If it started cold and the ice melted internally, Pluto would have contracted and we should see compression features on its surface, whereas if it started hot it should have expanded as the ocean froze and we should see extension features on the surface,” Bierson said. “We see lots of evidence of expansion, but we don’t see any evidence of compression, so the observations are more consistent with Pluto starting with a liquid ocean.”

Extensional faults (arrows) on the surface of Pluto indicate expansion of the dwarf planet’s icy crust, attributed to freezing of a subsurface ocean.
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker

The thermal and tectonic evolution of a cold-start Pluto is actually a bit complicated, because after an initial period of gradual melting the subsurface ocean would begin to refreeze. So compression of the surface would occur early on, followed by more recent extension. With a hot start, extension would occur throughout Pluto’s history.

“The oldest surface features on Pluto are harder to figure out, but it looks like there was both ancient and modern extension of the surface,” Nimmo said.

The next question was whether enough energy was available to give Pluto a hot start. The two main energy sources would be heat released by the decay of radioactive elements in the rock and gravitational energy released as new material bombarded the surface of the growing protoplanet.

Bierson’s calculations showed that if all of the gravitational energy was retained as heat, it would inevitably create an initial liquid ocean. In practice, however, much of that energy would radiate away from the surface, especially if the accretion of new material occurred slowly.

“How Pluto was put together in the first place matters a lot for its thermal evolution,” Nimmo said. “If it builds up too slowly, the hot material at the surface radiates energy into space, but if it builds up fast enough the heat gets trapped inside.”

The researchers calculated that if Pluto formed over a period of less that 30,000 years, then it would have started out hot. If, instead, accretion took place over a few million years, a hot start would only be possible if large impactors buried their energy deep beneath the surface.

The new findings imply that other large Kuiper belt objects probably also started out hot and could have had early oceans. These oceans could persist to the present day in the largest objects, such as the dwarf planets Eris and Makemake.

“Even in this cold environment so far from the sun, all these worlds might have formed fast and hot, with liquid oceans,” Bierson said.

In addition to Bierson and Nimmo, the paper was coauthored by Alan Stern at the Southwest Research Institute, the principal investigator of the New Horizons mission.

Contacts and sources:
Tim Stephens
University of California - Santa Cruz

Publication: Evidence for a hot start and early ocean formation on Pluto Carver J. Bierson, Francis Nimmo & S. Alan Stern Nature Geoscience (2020https://www.nature.com/articles/s41561-020-0595-0 http://dx.doi.org/10.1038/s41561-020-0595-0  Source: https://www.ineffableisland.com
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Secret features of smartphone must be known


Smartphone has some features that many users are not aware of, but these are very effective. These features can be of great help even in times of danger. Let us now know some of the features and tricks that are very effective. 

There is no need to turn off the video if you want to click a picture during make a video on smartphone. The iPhone also displays an icon of the photo while taking video, in where if you click it will capture pictures at the time of video being recorded. 

Many times the remote of the television, speaker or device at home goes bad, to know whether the remote is really damage or not, it can be known through the smartphone. Just place the remote sensor in front of the phone's camera and press the remote button. If the light on the remote sensor blinks, it indicates that the remote is OK and if the light does not blink, then it ensures of damaging condition of remote. 

Smartphone has a very good feature if you want to read any text on the screen when your eyesight is poor; which is called magnification. With this feature different parts of the screen can be zoomed. For this you have to tap the screen three times, it will zoom the screen. 

Nowadays smartphone has the feature of macro lens, which can take pictures of very small objects. Through this, the camera lens can be made more zoomed and smaller objects can be seen in larger resolutions without zooming.

Smartphone headphones are not only useful for listening to music, but also for taking pictures. Although this feature is not present in the earphones of all smartphones. However, it can be verified whether the smartphone has this feature or not. Source: https://www.daily-bangladesh.com/
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