четверг, 26 декабря 2019 г.

Palm-sized baby dinosaurs revealed in Australia


Researchers have uncovered the first baby dinosaurs from Australia. The bones were discovered at several sites along the south coast of Victoria and near the outback town of Lightning Ridge in New South Wales. Some of the bones are so tiny, they likely come from animals that had died while they were still in their eggs. Slightly larger bones from Victoria come from animals that had recently hatched but were probably nest-bound.

Palm-sized baby dinosaurs revealed in Australia
The femur (thigh bone) of a hatchling-sized ornithopod dinosaur from Victoria compared
to an Australian one-dollar coin [Credit: Justin Kitchener]
The research was carried out by palaeontologists from the Palaeoscience Research Centre at the University of New England and the Australian Opal Centre in Lightning Ridge.


The bones come from small-bodied ornithopod dinosaurs—two legged herbivores that weighed roughly 20kg when full grown—similar to Weewarrasaurus, which was recently discovered by members of the same team at Lightning Ridge. By comparison, the baby dinosaurs were only about 200g when they died, less that the weight of a cup of water.

While the eggs themselves were not found, researchers used growth rings in the bones, similar to the rings in a tree trunk, to estimate the animal's age. "Age is usually estimated by counting growth rings, but we couldn't do this with our two smallest specimens, which had lost their internal detail," says Justin Kitchener, a Ph.D. student at the University of New England, who also led the study. "To get around this, we compared the size of these bones with the size of growth rings from the Victorian dinosaurs. This comparison confidently places them at an early growth stage, probably prior to, or around the point of hatching."

Palm-sized baby dinosaurs revealed in Australia
Artist’s depiction of an ornithopod dinosaur tending its nest
[Credit: James Kuether]


100 million years ago, when these animals were being born, Australia was much closer to the poles. Southeastern Australia would have been between 60°S and 70°S, equivalent to modern day Greenland. Although the climate at these latitudes was relatively warmer than they are today, like some Antarctic penguins, these dinosaurs would have endured long dark winters and possibly burrowed or hibernated to survive.

Because they are so delicate, egg shell and tiny bones rarely survive to become fossils. "We have examples of hatchling-sized dinosaurs from close to the North Pole, but this is the first time we've seen this kind of thing anywhere in the Southern Hemisphere," says Dr. Phil Bell, a University of New England palaeontologist who recognised the significance of the tiny bones from Lightning Ridge. "It's the first clue we've had about where these animals were breeding and raising their young."

The study was published today in the journal Scientific Reports.

Source: University of New England [December 19, 2019]



* This article was originally published here

Ancient dwarfism skeleton tells story of acceptance


A remarkable 5000-year-old skeleton suggests human dwarfism was both accepted and respected in life and death in ancient China, research by a University of Otago bio-archaeologist shows.

Ancient dwarfism skeleton tells story of acceptance
The skeleton of M53 [Credit: University of Otago]
Associate Professor Sian Halcrow, from the University's Department of Anatomy, led the study on the skeleton and the stories it could tell.

The individual, a young adult referred to as burial M53, lived during the late Neolithic Yangshao period between 5300–4900 years ago in Guanjia—in Henan Province on the Central Plains of China.


M53 displayed evidence for skeletal dysplasia, characterized by proportional stunting of the long bones and a small axial skeleton, weakened bones and lack of skeletal maturity.

While firmly establishing age and gender was not possible, M53's remarkably well-preserved skeleton did offer up an intriguing insight into their life and death.

"They would have been visibly smaller than all other adults in the population," Associate Professor Halcrow says.

Ancient dwarfism skeleton tells story of acceptance
The skeletons teeth showed that it had died as a young adult
[Credit: Sian E. Halcrow et al., 2019]
"But they lived into adulthood so it's likely they were the recipient of care from other members in their family or wider society."

While it was difficult to model exactly what that care would have looked like at the time of M53's life, there is little doubt it existed, she says.


"That's because the dysplasia likely had some associated health effects from an early age, and that would have meant M53 would have had extra care needs."

Associate Professor Halcrow says the research tells a compelling story about how those living in the Henan Province 5000 years ago accepted each other—regardless of their physical differences.

"I think it is important for us to recognize that disability and difference can be found in the past, but that these things did not necessarily have negative connotations, socially or culturally. The ancient historical texts show that they may have, in fact, been revered in some situations."

The research was published this week in the International Journal of Paleopathology.

Author: Craig Bailey | Source:  University of Otago [December 20, 2019]



* This article was originally published here

In Brazil's pampas, a Triassic Park once flourished


Millions of years before the arrival of the mighty Tyrannosaurus rex, another fearsome dinosaur—the Gnathovorax—roamed what is now southern Brazil, ripping apart its prey with sharp teeth.

In Brazil's pampas, a Triassic Park once flourished
Paleontologist Rodrigo Temp Muller examines a dinosaur fossil at a research center in Sao Joao 
do Polesine, Brazil—the town is a treasure trove of fossils, and the site of the discovery 
of the first Gnathovorax skeleton [Credit: AFP]
Measuring nearly 10 feet (three meters) long, it was the biggest dinosaur of its time, and also the most ferocious—placing it at the top of the food chain, as T.rex once was.


Basically, the Gnathovorax cabreirai was the king of Triassic Park, if you will, as the dominant creature of the pre-Jurassic period that began roughly 250 million years ago.

"In the Triassic ecosystem, it held a place similar to what lions have today," says Rodrigo Temp Muller, a 26-year-old paleontologist at the Federal University of Santa Maria.

In Brazil's pampas, a Triassic Park once flourished
A foam model of the head of the Gnathovorax cabreirai is seen here—the dinosaur was the dominant creature 
of the Triassic period that began roughly 250 million years ago [Credit: AFP]
And the Gnathovorax's stomping grounds were the Brazilian pampas—sprawling plains that were then a fertile jungle of trees, mosses and non-flowering plants, and now are a gold mine for paleontologists.

About 100 dig sites filled with fossils are located in Rio Grande do Sul state, on Brazil's border with Argentina and Uruguay—and are yielding clues to help experts understand that long-ago era.

The first Gnathovorax skeleton was found in 2014 at Sao Joao do Polesine, a small town located about 300 kilometers (200 miles) west of the state capital Porto Alegre.

In Brazil's pampas, a Triassic Park once flourished
The first Gnathovorax skeleton was found in 2014 at Sao Joao do Polesine, and it is 
one of the oldest and best preserved dinosaur fossils ever discovered—parts
 of it are seen here [Credit: AFP]
Dating back more than 230 million years, it was one of the oldest and best preserved dinosaur fossils ever found—the skeleton was nearly complete. It's one of the oldest meat-eating dinosaurs ever identified.


"The fact that it is in such good condition allowed us to glean a large amount of information about its anatomy," Muller told AFP.

"It was a bipedal dinosaur that walked on its hind legs and had hooked claws to trap its prey," added the researcher, whose study was published last month in PeerJ.

In Brazil's pampas, a Triassic Park once flourished
Paleontologists Rodrigo Temp Muller (L) and Jose Darival Ferreira examine 
a newly found fossil at a dig site in Agudo, Brazil [Credit: AFP]
The Gnathovorax was only about 1.5 meters tall, and weighed about 70 to 80 kilos (150-175 pounds), Muller said.

Some of those characteristics were similar to those of T.rex, which appeared more than 150 million years later in North America at the very end of the Cretaceous period.

That dino could grow to more than 12 meters, but it was not a distant cousin to the Gnathovorax, which instead belongs to the Herrerasauridae family of dinosaurs of the Triassic period.

In Brazil's pampas, a Triassic Park once flourished
Paleontologist Rodrigo Temp Muller and the team he works on 
are studying several dinosaur species [Credit: AFP]
It appears to be more closely linked to other species whose fossils were found in Brazil and Argentina.


During the Triassic era, the continents were not separated as they are now, and dinosaurs were smaller than those that would follow in the Jurassic and Cretaceous periods. These dinosaurs eventually vanished in a massive flood plain.

"We've discovered numerous fossils across the region and there are surely more. The type of sediment that we have here is ideal for preserving fossils," Muller said. "The future is promising."

In Brazil's pampas, a Triassic Park once flourished
Brazilian researchers have found a nearly complete fossilized skeleton of the Macrocollum itaquii, 
the oldest long-necked dinosaur in the world [Credit: AFP]
At the Center for Paleontological Research at the Federal University of Santa Maria in Sao Joao do Polesine, the Gnathovorax skeleton is on display in a glass case.

The skull is particularly well preserved, and observers can easily see the dinosaur's powerful jaw that gives it its name—Gnathovorax cabreirai means "ravenous jaws."

Once the fossils were extracted from the soil, they were carefully examined with tools that look like a dentist's drill. In some cases, the work can take years.


The Gnathovorax is not the only species studied by the Brazilian research team. They also found impressive remains of the Macrocollum itaquii, the oldest long-necked dinosaur in the world, which lived about 225 million years ago.

Those fossils were found in 2012, on a vacant lot along a road in Agudo, about 20 kilometers outside Sao Joao do Polesine.


"It was also a biped, like the Gnathovorax, but it was a plant eater. Its teeth were adapted to eating plant matter, which it went to find high up because of its long neck," Muller said.

"It was one of the first dinosaurs for which we found a full skeleton in Brazil," he added.

These treasures are evidence of Brazil's rich paleontological history—one that partially went up in smoke last year when the National Museum in Rio was devastated by fire.

Numerous valuable collections were destroyed, including an impressive group of dinosaur fossils.

Author: Jordi Miro | Source: AFP [December 20, 2019]



* This article was originally published here

Inveravon Pictish Sculptured Stones, Aberdeenshire, Scotland, 21.12.19.

Inveravon Pictish Sculptured Stones, Aberdeenshire, Scotland, 21.12.19.



* This article was originally published here

Recent rise in CFC emissions could delay ozone hole healing by almost 20 years


The recently discovered increase in emissions of trichlorofluoromethane (CFC-11) may delay the recovery of the Antarctic ozone hole by over a decade if it continues, suggests a modelling study in Nature Communications. Although uncertainties exist regarding the levels of CFC-11 emissions and how they may vary, a rapid halt to their occurrence may limit the delay to only a few years.

Recent rise in CFC emissions could delay ozone hole healing by almost 20 years
Credit: NASA
CFC-11 contributes about one quarter of the anthropogenic chlorine transported into the stratosphere and its production is controlled by the 1987 Montreal Protocol. Following the implementation of the protocol, return of the Antarctic ozone hole to pre-depletion 1980 levels is expected to occur early in the second half of the 21st century. However, in 2018 it was reported that CFC-11 emissions had not been declining as expected since the mid-2000s. This is likely to be related to emissions from unreported production for foam use in China.


Martyn Chipperfield and colleagues used a detailed atmospheric chemical transport model to investigate the impact of these additional emissions on polar ozone recovery. The authors studied three possible CFC-11 emissions pathways: emissions stop immediately, they continue at a constant level, or they are phased out over the next 10 years.

The simulations suggest that the impact on the ozone hole has been limited so far. However, if emissions continue at a constant level, this could delay the ozone returning to 1980 values by around 18 years. If the emissions were phased out over the next decade, the delay will likely be no more than two years.

Source: Springer Nature [December 20, 2019]



* This article was originally published here

2019 December 26 The Northern Winter Hexagon Image Credit...



2019 December 26

The Northern Winter Hexagon
Image Credit & Copyright: Petr Horálek

Explanation: December’s New Moon brought a solar eclipse to some for the holiday season. It also gave beautiful dark night skies to skygazers around the globe, like this moonless northern winter night. In the scene, bright stars of the Winter Hexagon along the Milky Way are rising. Cosy mountain cabins in the snowy foreground are near the village of Oravska Lesna, Slovakia. The shining celestial beacons marking the well-known asterism are Aldebaran, Capella, Pollux (and Castor), Procyon, Rigel, and Sirius. This winter nightscape also reveals faint nebulae in Orion, and the lovely Pleiades star cluster. Slide your cursor over the image to trace the winter hexagon, or just follow this link.

∞ Source: apod.nasa.gov/apod/ap191226.html



* This article was originally published here

‘Nine Stanes of Mulloch’ Prehistoric Recumbent Stone Circle, Aberdeenshire, Scotland,...

‘Nine Stanes of Mulloch’ Prehistoric Recumbent Stone Circle, Aberdeenshire, Scotland, 22.12.19.



* This article was originally published here

Research points to unprecedented and worrying rise in sea levels


A new study led by Simon Fraser University's Dean of Science, Prof. Paul Kench, has discovered new evidence of sea-level variability in the central Indian Ocean.

Research points to unprecedented and worrying rise in sea levels
Credit: Carolyn Cole/Los Angeles Times
The study, which provides new details about sea levels in the past, concludes that sea levels in the central Indian Ocean have risen by close to a meter in the last two centuries.

Prof. Kench says, "We know that certain types of fossil corals act as important recorders of past sea levels. By measuring the ages and the depths of these fossil corals, we are identifying that there have been periods several hundred years ago that the sea level has been much lower than we thought in parts of the Indian Ocean."


He says understanding where sea levels have been historically, and what happens as they rise, will provide greater insights into how coral reefs systems and islands may be able to respond to the changes in sea levels in the future.

Underscoring the serious threat posed to coastal cities and communities in the region, the ongoing study, which began in 2017, further suggests that if such acceleration continues over the next century, sea levels in the Indian Ocean will have risen to their highest level ever in recorded history.

The research paper was published this week in the scientific journal Nature Geoscience.

Author: Shradhha Sharma | Source: Simon Fraser University [December 19, 2019]



* This article was originally published here

Loanhead of Daviot Prehistoric Recumbent Stone Circle, Aberdeenshire, Scotland, 21.12.19.

Loanhead of Daviot Prehistoric Recumbent Stone Circle, Aberdeenshire, Scotland, 21.12.19.



* This article was originally published here

Hubble's close-up of spiral's disk, bulge


This image from the NASA/ESA Hubble Space Telescope shows IC 2051, a galaxy in the southern constellation of Mensa (the Table Mountain) lying about 85 million light-years away. It is a spiral galaxy, as evidenced by its characteristic whirling, pinwheeling arms, and it has a bar of stars slicing through its center.

Hubble's close-up of spiral's disk, bulge
IC 2051 [Credit: ESA/Hubble & NASA, P. Erwin et al.]
This galaxy was observed for a Hubble study on galactic bulges, the bright round central regions of spiral galaxies. Spiral galaxies like IC 2051 are shaped a bit like flying saucers when seen from the side; they comprise a thin, flat disk, with a bulky bulge of stars in the center that extends above and below the disk.


These bulges are thought to play a key role in how galaxies evolve, and to influence the growth of the supermassive black holes lurking at the centers of most spirals. While more observations are needed in this area, studies suggest that some, or even most, galactic bulges may be complex composite structures rather than simple ones, with a mix of spherical, disk-like, or boxy components, potentially leading to a wide array of bulge morphologies in the universe.

This image comprises data from Hubble's Wide Field Camera 3 at visible and infrared wavelengths.

Source: NASA's Goddard Space Flight Center [December 20, 2019]



* This article was originally published here

Enclosed Prehistoric Cremation Cemetery, Daviot, Aberdeenshire, 21.12.19.

Enclosed Prehistoric Cremation Cemetery, Daviot, Aberdeenshire, 21.12.19.



* This article was originally published here

Scientists find iron 'snow' in Earth's core


The Earth's inner core is hot, under immense pressure and snow-capped, according to new research that could help scientists better understand forces that affect the entire planet.

Scientists find iron 'snow' in Earth's core
A simplified graphic of the inner Earth as described by the new research. The white and black layers represent
 a slurry layer containing iron crystals. The iron crystals form in the slurry layer of the outer core (white).
These crystals 'snow' down to the inner core, where they accumulate and compact into a layer on top
of it (black). The compacted layer is thicker on the western hemisphere of the inner core (W) than
on the eastern hemisphere (E) [Credit: University of Texas at Austin/
Jackson School of Geosciences]
The snow is made of tiny particles of iron -- much heavier than any snowflake on Earth's surface -- that fall from the molten outer core and pile on top of the inner core, creating piles up to 200 miles thick that cover the inner core.

The image may sound like an alien winter wonderland. But the scientists who led the research said it is akin to how rocks form inside volcanoes.

"The Earth's metallic core works like a magma chamber that we know better of in the crust," said Jung-Fu Lin, a professor in the Jackson School of Geosciences at The University of Texas at Austin and a co-author of the study.


Youjun Zhang, an associate professor at Sichuan University in China, led the study. The other co-authors include Jackson School graduate student Peter Nelson; and Nick Dygert, an assistant professor at the University of Tennessee who conducted the research during a postdoctoral fellowship at the Jackson School.

The Earth's core can't be sampled, so scientists study it by recording and analyzing signals from seismic waves (a type of energy wave) as they pass through the Earth.

However, aberrations between recent seismic wave data and the values that would be expected based on the current model of the Earth's core have raised questions. The waves move more slowly than expected as they passed through the base of the outer core, and they move faster than expected when moving through the eastern hemisphere of the top inner core.

The study proposes the iron snow-capped core as an explanation for these aberrations. The scientist S.I. Braginkskii proposed in the early 1960s that a slurry layer exists between the inner and outer core, but prevailing knowledge about heat and pressure conditions in the core environment quashed that theory. However, new data from experiments on core-like materials conducted by Zhang and pulled from more recent scientific literature found that crystallization was possible and that about 15% of the lowermost outer core could be made of iron-based crystals that eventually fall down the liquid outer core and settle on top of the solid inner core.


"It's sort of a bizarre thing to think about," Dygert said. "You have crystals within the outer core snowing down onto the inner core over a distance of several hundred kilometers."

The researchers point to the accumulated snow pack as the cause of the seismic aberrations. The slurry-like composition slows the seismic waves. The variation in snow pile size -- thinner in the eastern hemisphere and thicker in the western -- explains the change in speed.

"The inner-core boundary is not a simple and smooth surface, which may affect the thermal conduction and the convections of the core," Zhang said.

The paper compares the snowing of iron particles with a process that happens inside magma chambers closer to the Earth's surface, which involves minerals crystalizing out of the melt and glomming together. In magma chambers, the compaction of the minerals creates what's known as "cumulate rock." In the Earth's core, the compaction of the iron contributes to the growth of the inner core and shrinking of the outer core.


And given the core's influence over phenomena that affects the entire planet, from generating its magnetic field to radiating the heat that drives the movement of tectonic plates, understanding more about its composition and behavior could help in understanding how these larger processes work.

Bruce Buffet, a geosciences professor at the University of California, Berkley who studies planet interiors and who was not involved in the study, said that the research confronts longstanding questions about the Earth's interior and could even help reveal more about how the Earth's core came to be.

"Relating the model predictions to the anomalous observations allows us to draw inferences about the possible compositions of the liquid core and maybe connect this information to the conditions that prevailed at the time the planet was formed," he said. "The starting condition is an important factor in Earth becoming the planet we know."

The study is published in the  journal JGR Solid Earth.

Source: University of Texas at Austin [December 19, 2019]



* This article was originally published here

A step closer to understanding evolution - mitochondrial division conserved across species


Cellular origin is well explained by the "endosymbiotic theory," which famously states that higher organisms called "eukaryotes" have evolved from more primitive single-celled organisms called "prokaryotes." This theory also explains that mitochondria -- energy-producing factories of the cell -- are actually derived from prokaryotic bacteria, as part of a process called "endosymbiosis." Biologists believe that their common ancestry is why the structure of mitochondria is "conserved" in eukaryotes, meaning that it is very similar across different species -- from the simplest to most complex organisms.

A step closer to understanding evolution - mitochondrial division conserved across species
Exciting new research describes how mitochondrial replication is similar in the simplest to most
complex organisms, shedding light on its origin [Credit: Tokyo University of Science]
Now, it is known that as cells divide, so do mitochondria, but exactly how mitochondrial division takes place remains a mystery. Is it possible that mitochondria across different multicellular organisms -- owing to their shared ancestry -- divide in an identical manner? Considering that mitochondria are involved in some of the most crucial processes in the cell, including the maintenance of cellular metabolism, finding the answer to exactly how they replicate could spur further advancements in cell biology research.


In a new study published in Communications Biology, a group of scientists at Tokyo University of Science, led by Prof Sachihiro Matsunaga, wanted to find answers related to the origin of mitochondrial division. For their research, Prof Matsunaga and his team chose to study a type of red alga -- the simplest form of a eukaryote, containing only one mitochondrion. Specifically, they wanted to observe whether the machinery involved in mitochondrial replication is conserved across different species and, if so, why. Talking about the motivation for this study, Prof Matsunaga says, "Mitochondria are important to cellular processes, as they supply energy for vital activities. It is established that cell division is accompanied by mitochondrial division; however, many points regarding its molecular mechanism are unclear."

The scientists first focused on an enzyme called Aurora kinase, which is known to activate several proteins involved in cell division by "phosphorylating" them (a well-known process in which phosphate groups are added to proteins to regulate their functions). By using techniques such as immunoblotting and kinase assays, they showed that the Aurora kinase in red algae phosphorylates a protein called dynamin, which is involved in mitochondrial division. Excited about these findings, Prof Matsunaga and his team wanted to take their research to the next level by identifying the exact sites where Aurora kinase phosphorylates dynamin, and using mass spectrometric experiments, they succeeded in identifying four such sites. Prof Matsunaga says, "When we looked for proteins phosphorylated by Aurora kinase, we were surprised to find dynamin, a protein that constricts mitochondria and promotes mitochondrial division."


Having gained a little more insight into how mitochondria divide in red algae, the scientists then wondered if the process could be similar in more evolved eukaryotes, such as humans. Prof Matsunaga and his team then used a human version of Aurora kinase to see if it phosphorylates human dynamin -- and just as they predicted, it did. This led them to conclude that the process by which mitochondria replicate is very similar in different eukaryotic organisms. Prof Matsunaga elaborates on the findings by saying, "Using biochemical in vitro assays, we showed that Aurora kinase phosphorylates dynamin in human cells. In other words, it was found that the mechanism by which Aurora kinase phosphorylates dynamin in the mitochondrion is preserved from primitive algae to humans."

Scientists have long pondered over the idea of mitochondrial division being conserved in eukaryotes. This study is the first to show not only the role of a new enzyme in mitochondrial replication but also that this process is similar in both algae and humans, hinting towards the fact that their common ancestry might have something to do with this. Prof Matsunaga concludes by talking about the potential implications of this study, "Since the mitochondrial fission system found in primitive algae may be preserved in all living organisms including humans, the development of this method can make it easier to manipulate cellular activities of various organisms, as and when required."

As it turns out, we have much more in common with other species than we thought, and part of the evidence lies in our mitochondria!

Source: Tokyo University of Science [December 20, 2019]



* This article was originally published here

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