четверг, 11 июля 2019 г.

Anatomy Lives On A brain scan of unprecedented resolution…


Anatomy Lives On


A brain scan of unprecedented resolution shows the intricate neuroanatomy of a deceased 58-year-old woman’s brain, which was treated with a chemical and imaged continuously for five days in a custom-built scanner. Key to its high-resolution is the fact that the scan lasted much longer than would be possible in a living person and had no risk of movements blurring the image. Previous methods could only scan post-mortem tissue in small sections. The whole brain in this video has tissue of two shades. A typical scan of a living brain shows grey tissue on the brain’s outer surface, where cells are tightly packed together. These cells send messages along wires that are coated in fat, making the brain’s inner tissue appear white. Here, the scanner’s contrast makes the shades of grey and white appear reversed. This new approach could help researchers identify links between brain anatomy and disease.


Written by Deborah Oakley



You can also follow BPoD on Instagram, Twitter and Facebook


Archive link


Hubble Discovers Mysterious Black Hole Disc



 PR Image heic1913a


Artist’s impression of NGC3147 black hole disc 





Top-Down view of artist’s impression of NGC3147 black hole disc



PR Image heic1913c


Galaxy NGC 3147 





Videos



Artist’s Impression of NGC3147 black hole disc


Artist’s Impression of NGC3147 black hole disc


Top-Down View of Artist’s Impression of NGC3147 black hole disc



Top-Down View of Artist’s Impression of NGC3147 black hole disc





Astronomers using the NASA/ESA Hubble Space Telescope have observed an unexpected thin disc of material encircling a supermassive black hole at the heart of the spiral galaxy NGC 3147, located 130 million light-years away.


The presence of the black hole disc in such a low-luminosity active galaxy has astronomers surprised. Black holes in certain types of galaxies such as NGC 3147 are considered to be starving as there is insufficient gravitationally captured material to feed them regularly. It is therefore puzzling that there is a thin disc encircling a starving black hole that mimics the much larger discs found in extremely active galaxies. 


Of particular interest, this disc of material circling the black hole offers a unique opportunity to test Albert Einstein’s theories of relativity. The disc is so deeply embedded in the black hole’s intense gravitational field that the light from the gas disc is altered, according to these theories, giving astronomers a unique peek at the dynamic processes close to a black hole. 


We’ve never seen the effects of both general and special relativity in visible light with this much clarity,” said team member Marco Chiaberge of AURA for ESA, STScI and Johns Hopkins Univeristy.


The disc’s material was measured by Hubble to be whirling around the black hole at more than 10% of the speed of light. At such extreme velocities, the gas appears to brighten as it travels toward Earth on one side, and dims as it speeds away from our planet on the other. This effect is known as relativistic beaming. Hubble’s observations also show that the gas is embedded so deep in a gravitational well that light is struggling to escape, and therefore appears stretched to redder wavelengths. The black hole’s mass is around 250 million times that of the Sun. 


This is an intriguing peek at a disc very close to a black hole, so close that the velocities and the intensity of the gravitational pull are affecting how we see the photons of light,” explained the study’s first author, Stefano Bianchi, of Università degli Studi Roma Tre in Italy. 


In order to study the matter swirling deep inside this disc, the researchers used the Hubble Space Telescope Imaging Spectrograph (STIS) instrument. This diagnostic tool divides the light from an object into its many individual wavelengths to determine the object’s speed, temperature, and other characteristics at very high precision. STIS was integral to effectively observing the low-luminosity region around the black hole, blocking out the galaxy’s brilliant light. 


The astronomers initially selected this galaxy to validate accepted models about lower-luminosity active galaxies: those with malnourished black holes. These models predict that discs of material should form when ample amounts of gas are trapped by a black hole’s strong gravitational pull, subsequently emitting lots of light and producing a brilliant beacon called a quasar


The type of disc we see is a scaled-down quasar that we did not expect to exist,” Bianchi explained. “It’s the same type of disc we see in objects that are 1000 or even 100 000 times more luminous. The predictions of current models for very faint active galaxies clearly failed.



The team hopes to use Hubble to hunt for other very compact discs around low-luminosity black holes in similar active galaxies.




More Information




The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

The team’s paper will appear in the journal the Monthly Notices of the Royal Astronomical Society.


The international team of astronomers in this study consists of Stefano Bianchi (Universita` degli Studi Roma Tre, Italy), Robert Antonucci (University of California, Santa Barbara, USA), Alessandro Capetti (INAF — Osservatorio Astrofisico di Torino, Italy), Marco Chiaberge (Space Telescope Science Institute and Johns Hopkins University, Baltimore, USA), Ari Laor (Israel Institute of Technology, Israel), Loredana Bassani (INAF/IASF Bologna, Italy), Francisco J. Carrera (CSIC-Universidad de Cantabria, Spain), Fabio La Franca (Universita` degli Studi Roma Tre, Italy), Andrea Marinucci (Universita` degli Studi Roma Tre, Italy), Giorgio Matt1 (Universita` degli Studi Roma Tre, Italy), Riccardo Middei (Universita` degli Studi Roma Tre, Italy), Francesca Panessa (INAF Istituto di Astrofisica e Planetologia Spaziali, Italy).


Image credit: ESA/Hubble, M. Kornmesser 




Links






Contacts


Stefano Bianchi
Dipartimento di Matematica e Fisica, Universita` degli Studi Roma Tre
Rome, Italy
Email:
bianchi@fis.uniroma3.it


Bethany Downer
ESA/Hubble, Public Information Officer
Garching, Germany
Email:
bethany.downer@partner.eso.org








Archive link


2019 July 11 The Ghost of Jupiter’s Halo Image Credit…


2019 July 11


The Ghost of Jupiter’s Halo
Image Credit & Copyright: CHART32 Team, Processing — Johannes Schedler / Volker Wendel


Explanation: Close-up images of NGC 3242 show the cast off shroud of a dying, sun-like star fancifully known as The Ghost of Jupiter nebula. But this deep and wide telescopic view also finds the seldom seen outer halo of the beautiful planetary nebula at the upper left, toward Milky Way stars and background galaxies in the serpentine constellation Hydra. Intense and otherwise invisible ultraviolet radiation from the nebula’s central white dwarf star powers its illusive glow in visible light. In fact, planets of NGC 3242’s evolved white dwarf star may have contributed to the nebula’s symmetric features and shape. Activity beginning in the star’s red giant phase, long before it produced a planetary nebula, is likely the cause of the fainter more extensive halo. About a light-year across NGC 3242 is some 4,500 light-years away. The tenuous clouds of glowing material at the right could well be interstellar gas, by chance close enough to the NGC 3242’s white dwarf to be energized by its ultraviolet radiation.


∞ Source: apod.nasa.gov/apod/ap190711.html


Unique Roman gold coin found in Lower Saxony

A gold coin weighing nine grams, which was found on a field in Fredenbeck, Lower Saxony, in the district of Stade, in December 2017 and has since been scientifically examined and restored, is unique worldwide.











Unique Roman gold coin found in Lower Saxony
Gold Multiplum of the Emperor Constans, 342-3 AD, found in Lower Saxony
[Credit: Christina Kohnen (Cologne)]

«Thanks to the support of the Ernst von Siemens Kunststiftung, the Landschaftsverband Stade and the Landkreis Stade, the rare piece has now been purchased for the permanent exhibition in the Museum Schwedenspeicher,» said Michael Roesberg, District Administrator of Stad.


The so-called Multiplum, a «special coin» (diameter 29 millimeters) with the portrait of the Roman emperor Constans from the 4th century, is now on permanent display in the Stader Museum Schwedenspeicher. Metal detectorist Matthias Glüsing made the sensational discovery in the area of prehistoric burial mounds. He had systematically examined areas in the joint municipality of Fredenbeck with the approval of regional archaeology authorities.


Multipla are particularly valuable mintings of common Roman coins which were only issued on special occasions and handed over to prominent personalities by the Roman emperors in the course of festive and special ceremonies. They belonged to a circle of individuals on whose loyalty the ruler was particularly dependent: highest dignitaries, commanders of the Roman armed forces and imperial bodyguards. They received a multiplum for their services on the occasion of the enthronement of a new emperor, a celebration of his accession to the throne, before and after campaigns or other important events. Friends of Germanic rulers could also be awarded the imperial large coins.


On the obverse of the coin is the portrait of Emperor Constans with a diadem and armour. Constans was born between 320 and 323 and was killed on February 350. He was the youngest son of Emperor Constantine the Great. After his father died in 337, he ruled the Roman Empire together with his brothers. After the victory over his brother Constantine II in 340, the entire western part of the empire, including Britain, Gaul and the Iberian Peninsula, fell to him. The coin was minted in the years 342/343 in Siscia (today Sisak/Croatia). The nine gram heavy multiplum is a worldwide unique specimen — there are no other parallels.


Gold multipla have rarely been found in the area outside the borders of the Roman Empire. In free Germania they were special status symbols with which Germanic rulers legitimized their power. The princes often wore their multipla around their necks in a representative and orderly manner.











Unique Roman gold coin found in Lower Saxony
Presenting the coin (from right): Daniel Nösler (district archaeologist), Matthias Glüsing (metal detectorist and
finder of the coin), district administrator Michael Roesberg and Hans-Eckard Dannenberg (Stade History Club)
[Credit: Christian Schmidt/Landkreis Stade]

«It can be assumed that the former owner was a prince or king of the Saxon great tribe that emerged during this period. There is good evidence that this prominent member of the Saxon elite was awarded the multiplum as a gift from the emperor for military service or for alliances kept,» explains Daniel Nösler, district archaeologist at Stad.


Germanic auxiliary troops have been reported several times during the reign of Constans. «The gold multiplum is thus the earliest archaeological evidence of the existence of a Saxon elite in Lower Saxony from a time when written records are scarce,» says Nösler.


The sensational discovery had been intensively researched in recent months: An excavation was carried out at the site and metal detectors were used to locate it. In addition, the archaeologists evaluated historical maps and aerial photographs. «So far, there is good evidence to suggest that the gold coin was offered at a special site, which was characterised by a small moor, a striking group of burial mounds, an ancient path and an impressive hill,» says Nösler.


After more than 1,600 years, this extraordinary piece has now been rediscovered.


District Administrator Michael Roesberg acknowledges the commitment of the sponsors: «The purchase, which was made possible by the Ernst von Siemens Kunststiftung, the Landschaftsverband Stade and the Landkreis Stade, means that the multiplum can be permanently presented to the public in the Stader Museum Schwedenspeicher. This adds a unique attraction to our museum landscape. The donors, the finder and the property owner are very grateful for this.»


«The finder, the Department for the Preservation of Historical Monuments and the Stade Museums have worked together in an exemplary manner. A gold coin of unique cultural value and testimony to the connection between the late ancient Roman emperor Constans and a Germanic ruler can thus be presented to the public near where it was found. The Ernst von Siemens Kunststiftung was happy to support the purchase,» says Dr. Martin Hoernes, Secretary General of the Ernst von Siemens Kunststiftung.


Dr. Sebastian Möllers, Director of the Stade Museums, is of course also enthusiastic: «The Multiplum is a real highlight for our recently opened permanent exhibition on prehistory and early history in the Elbe-Weser Triangle. Although we do have to rearrange a few things, we are naturally not afraid of any extra work for such a special piece.


Source: Landkreis Stade [July 08, 2019]



TANN



Archive


Global25 workshop 4: a neighbor joining tree of ancient and present-day West Eurasian...

Phylogenetic trees are easy to produce, but there’s an infinite number of ways to run them, and, depending on the input data you’re using, some methods are a lot more effective than others. In this tutorial I’m going to demonstrate one method that has worked well for me when looking at the fine scale genetic relationships between ancient and present-day human populations with my Global25 data.
To get started download this datasheet, plug it into the PAST program, which is freely available here, then select all of the columns by clicking on the empty tab above the labels, and choose Multivariate > Clustering > Neighbor joining. Here’s a screen cap of me doing just that…



Then, from the tabs on the right, choose Chord as the similarity index and ZAF_2100BP — an ancient forager from Southern Africa and the most distinct unit in the datasheet — as the root. PAST offers an exceptionally large range of similarity indices and they generally produce similar results, but, in my experience, Chord creates among the most visually pleasing outcomes when dealing with fine scale genetic substructures.



This is the tree you should see after exporting the image via the graph settings tab in PAST, and, if you like, rotating it 90 degrees with an image editing software of your choice. Note the fairly substantial differences between the populations from Northwestern Europe, which are often difficult to tease apart in such analyses.



If you have your own Global25 coordinates you can add them to my PAST-compatible datasheet to see where you cluster in this tree. And, of course, you can design your own PAST-compatible datasheets and trees with any combination of populations and/or individuals from the Global25 text files at the links below. It’s easy; just copy paste the coordinates of your choice into an empty text file, open it with PAST and then save it with the dat extension to create a new PAST datasheet. But make sure never to mix up the scaled and non-scaled coordinates.



Global 25 datasheet (scaled)
Global 25 pop averages (scaled)
Global 25 datasheet
Global 25 pop averages



An important point to keep in mind when running these sorts of analyses is that PAST and other such programs need enough genetic differentiation to latch onto in order to produce meaningful results. Thus, even when studying the relationships between very closely related populations, it’s not just useful to include a root population or individual, but also some near and far related groups to help the analysis algorithm flesh out the key genetic substructures.
To be honest, I don’t really know whether using the Chord index and rooting the tree with an ancient Southern African is the best way to run a neighbor joining tree analysis of ancient and present-day West Eurasian genetic variation. What do you think? Feel free to let me know in the comments.
See also…
Global25 workshop 1: that classic West Eurasian plot
Global25 workshop 2: intra-European variation
Global25 workshop 3: genes vs geography in Northern Europe
Genetic ancestry online store (to be updated regularly)

Source


Body plan evolution not as simple as once believed

The role of Hox genes in changing the layout of different body parts during evolution has been challenged by a study led by researchers out of the University of Pittsburgh’s Department of Biological Sciences.











Body plan evolution not as simple as once believed
The left side is a rendering of a Drosophila yakuba male fly while the right side is a Drosophila santomea male.
Drosophila santomea has lost most of its body coloration during the .5 million years since the two species
 diverged, including bands of pigmentation that adorn each abdominal segment and the full
pigmentation of posterior segments [Credit: Eden Wellesley McQueen]

Hox genes are vital to developing differences in repeated body parts such as vertebrae, limbs, or digits in most animal species, including human beings. Ever since their discovery, scientists have thought that modifications to Hox genes could be the primary way that the animal body plan has been altered during evolution.
The paper, published in Current Biology, discusses experiments that pinpoint evolutionary changes in a Hox gene, but found that several other genes had evolved alongside it to generate a difference in pigmentation along the fruit fly body plan.


The experiment identified evolutionary modifications in Hox gene Abd-B that caused a drastic loss of expression on the body of the Dropsophila santomea (D. santomea) fruit fly. The same gene is necessary for the fruit fly’s sister species, Dropsophila yakuba (D. yakuba,) to express body pigmentation, so changes to that gene were expected to cause a loss of pigmentation across the species.


However, when researchers restored the D yakuba Abd-b gene to D. santomea, it did not restore or increase the amount of pigmentation shown. Researchers said that outcome is the result of four other genes within the D. santomea pigmentation network, three of which evolved in ways that prevent it from responding to Hox gene Abd-B.


«Hox genes are clearly very important regulators of animal development, setting up animal body plans and showing signs of change in all sorts of creatures whose body plans differ. This work shows just how complex the process of evolving those differences can be. It takes all sorts of genes working together to generate these phenotypes,» said Mark Rebeiz, an associate professor of evolutionary development who was a lead author on the paper.


Source: University of Pittsburgh [July 09, 2019]



TANN



Archive


Human pregnancy dependent on cells evolved in platypus-like animal 300 million years ago

Platelet cells, which prevent mammals from bleeding non-stop, first evolved around 300 million years ago in an egg-laying animal similar to the modern duck-billed platypus, finds joint research by UCL and Yale University.











Human pregnancy dependent on cells evolved in platypus-like animal 300 million years ago
Platypus [Credit: Klaus/Flickr]

This event was a prerequisite for the origin of placental development in mammals, including human beings.


The paper, published as a peer-reviewed opinion piece in Biology Letters, suggests that platelet cells were critical in the evolution of eutherian mammals, to which humans belong, and which are distinguished by a deep invasive placenta (haemochorial placentation), by where maternal blood comes in direct contact with the fetus.


Co-led by Professors John Martin (UCL Division of Medicine) and Günter Wagner (Yale University), the research finds that platelet cells, which clot blood caused by cuts or lesions, enabled haemochorial placentation, helping the mother prevent haemorrhaging at birth.


In the paper researchers show that an egg-laying animal similar to a modern duck-billed platypus started creating platelets — possibly by chance — and these were passed on when this animal group diverged around 300 million years ago into monotremes (the first mammal group), of which the existing duck-billed platypus and echidna are living descendants, marsupials (also mammals) and eutherian mammals, which include modern humans.


UCL Professor of Cardiovascular Medicine, John Martin, said: «We have shown with convincing evidence that platelets occurred 300 million years ago even before monotremes arose.


«This unique feature subsequently allowed the placenta to develop, which led to the eutherian mammals and therefore human beings.


«During birth, safe disconnection of the placenta from the uterus is essential for the survival of the mother and child, so without platelets, neither would have survived and the evolutionary step to eutherian mammals, including human beings, would never have happened.»


This research was undertaken as part of the ‘Yale UCL Collaborative’: a strong relationship between the two universities designed to increase creativity.


Yale Professor of Ecology and Evolutionary Biology, Günter Wagner, said: «The unique presence of platelets in mammals explains why deeply invasive placentation is limited to mammals, even though live birth is found in many other animal lineages, but not invasive placentation.»


The authors met through the ‘Yale UCL Collaborative’, which promotes joint research and student exchange, and this year is celebrating 10 years, since its inception.


Professor Martin said: «The primary goal of the Yale UCL Collaborative is to reach higher levels of creativity and quality of idea than we would have achieved alone.


«Through this partnership, I have been able to work with Professor Wagner, a world-leading expert in evolutionary biology, and test and challenge my theory of the evolution of eutherian placentation.


«Through this joint research we have concluded the origins of platelets ultimately led to human evolution.»


Source: University College London [July 09, 2019]



TANN



Archive


Earliest known Homo sapiens in Eurasia found in Greece

Early modern humans left Africa earlier than previously assumed, reaching Europe nearly 150,000 years earlier than previously known, indicates research led by the Universities of Tübingen and Athens. After comprehensive analyses, scientists identified a skull from the Apidima site, southern Greece, as early Homo sapiens and dated it to about 210,000 years ago. This makes it the earliest modern human known outside Africa, says the international team led by Professor Katerina Harvati from the Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen.











Earliest known Homo sapiens in Eurasia found in Greece
The Apidima 2 cranium (right) and its reconstruction (left). Apidima 2 shows a suite of features
characteristic of Neanderthals, indicating that it belongs to the Neanderthal lineage
[Credit: Katerina Harvati, Eberhard Karls University of Tübingen]

The fossil find, Apidima 1, originates from the site of Apidima, southern Greece and was found together with another human fossil, Apidima 2, during research by the Museum of Anthropology of the University of Athens in the late 1970s.


The research team applied novel, cutting edge approaches, including virtual reconstructions of the damaged parts of the skulls. It conducted numerous comparisons with different human fossils, and used a highly accurate radiometric dating method to determine their age.


«Apidima 2 is about 170,000 years old. We could tell that it was a Neanderthal,» says Katerina Harvati. «Surprisingly, Apidima 1 is even older, about 210,000 years old, but has no Neanderthal features.» Rather, the study revealed a mixture of modern human and archaic characteristics, indicating an early Homo sapiens.


Complex ancestry


«Our results suggest that at least two groups of people lived in the Middle Pleistocene in what is now southern Greece: an early population of Homo sapiens and, later, a group of Neanderthals,» says Harvati. This supports the hypothesis that early modern humans spread out of Africa, where they evolved, multiple times.











Earliest known Homo sapiens in Eurasia found in Greece
The Apidima 1 partial cranium (right) and its reconstruction from posterior view (middle) and side view (left).
The rounded shape of the Apidima 1 cranium a unique feature of modern humans and contrasts
sharply with Neanderthals and their ancestors [Credit: Katerina Harvati,
Eberhard Karls University of Tübingen]

«The Apidima 1 skull shows an early dispersal happened earlier than we thought, and also reached further geographically, into Europe itself.» Apidima 1 is more than 150 thousand years older than the oldest modern human specimens known from Europe until now.


«We hypothesize that, as in the Near East, the early modern human population represented by Apidima 1 was probably replaced by Neanderthals, whose presence in southern Greece is well documented, including by the Apidima 2 skull from the same site,” says Harvati, outlining what appears to have happened.


But Neanderthals also had to make way. In the late Palaeolithic, some 40,000 years ago, newly-arrived modern humans settled in the region, as in the rest of Europe. Their presence is documented by finely-worked stone tools and other finds. Neanderthals became extinct around this time. «This discovery highlights the importance of Southeast Europe for human evolution «, concludes Harvati.


The Apidima cave was excavated in the 1970s and -80s by the Museum of Anthropology of the Medical School of the University of Athens. The Museum was founded in 1886, and is one of the earliest of its kind in Europe. It has played an important role, not only in research ‒ most notably the excavations at Apidima ‒ but also in educating the public.











Earliest known Homo sapiens in Eurasia found in Greece
The Apidima cave complex, seen from the sea [Credit: Eberhard Karls
University of Tübingen]

The researchers plan further studies of the Apidima material, long considered important for human evolution, but shown to be of even greater significance by the new results. «The Museum of Anthropology houses these important finding from our excavations of the Apidima site. This publication is the first in a series of detailed studies that we plan in collaboration with the team of Prof. Harvati» says Professor Kouloukoussa, the Museum’s director.


Professor Gorgoulis, head of the Department of Histology and Embryology at the University of Athens, adds «This is another example of the University of Athens’ cutting edge research. We are very happy that these findings are now receiving international recognition, resulting from the successful collaborative research led by our institutions.»


The study was published in the journal Nature.


Source: Eberhard Karls University of Tuebingen [July 10, 2019]



TANN



Archive


Supercomputer shows ‘Chameleon Theory’ could change how we think about...

Supercomputer simulations of galaxies have shown that Einstein’s theory of General Relativity might not be the only way to explain how gravity works or how galaxies form.











Supercomputer shows 'Chameleon Theory' could change how we think about gravity
Computer generated images showing a disk galaxy from a modified gravity simulation.Images show (right side of image,
in red-blue color) the gas density within the disk of the galaxy with the stars shown as bright dots. The left side of the
 images show the force changes in the gas within the disk, where the dark central regions correspond to standard,
General Relativity-like forces and the bright yellow regions correspond to enhanced (modified forces).
Images show views of the simulated galaxy from above and the side
[Credit: Christian Arnold/Baojiu Li/Durham University]

Physicists at Durham University, UK, simulated the cosmos using an alternative model for gravity — f(R)-gravity, a so called Chameleon Theory. The resulting images produced by the simulation show that galaxies like our Milky Way could still form in the universe even with different laws of gravity.


The findings show the viability of Chameleon Theory — so called because it changes behaviour according to the environment — as an alternative to General Relativity in explaining the formation of structures in the universe. The research could also help further understanding of dark energy — the mysterious substance that is accelerating the expansion rate of the universe.


General Relativity was developed by Albert Einstein in the early 1900s to explain the gravitational effect of large objects in space, for example to explain the orbit of Mercury in the solar system. It is the foundation of modern cosmology but also plays a role in everyday life, for example in calculating GPS positions in smartphones. Scientists already know from theoretical calculations that Chameleon Theory can reproduce the success of General Relativity in the solar system.


The Durham team has now shown that this theory allows realistic galaxies like our Milky Way to form and can be distinguished from General Relativity on very large cosmological scales. Research co-lead author Dr Christian Arnold, in Durham University’s Institute for Computational Cosmology, said: «Chameleon Theory allows for the laws of gravity to be modified so we can test the effect of changes in gravity on galaxy formation. Through our simulations we have shown for the first time that even if you change gravity, it would not prevent disc galaxies with spiral arms from forming. Our research definitely does not mean that General Relativity is wrong, but it does show that it does not have to be the only way to explain gravity’s role in the evolution of the universe.»











Supercomputer shows 'Chameleon Theory' could change how we think about gravity
Computer generated images showing a disk galaxy from a modified gravity simulation
are available.Images show (right side of image, in red-blue color) the gas density
within the disk of the galaxy with the stars shown as bright dots. The left side of the
 images show the force changes in the gas within the disk, where the dark central regions
 correspond to standard, General Relativity-like forces and the bright yellow regions
correspond to enhanced (modified forces). Images show views of thesimulated galaxy
 from above and the side [Credit: Christian Arnold/Baojiu Li/Durham University]

The researchers looked at the interaction between gravity in Chameleon Theory and supermassive black holes that sit at the centre of galaxies. Black holes play a key role in galaxy formation because the heat and material they eject when swallowing surrounding matter can burn away the gas needed to form stars, effectively stopping star formation.


The amount of heat spewed out by black holes is altered by changing gravity, affecting how galaxies form. However, the new simulations showed that even accounting for the change in gravity caused by applying Chameleon Theory, galaxies were still be able to form.


General Relativity also has consequences for understanding the accelerating expansion of the universe. Scientists believe this expansion is being driven by dark energy and the Durham researchers say their findings could be a small step towards explaining the properties of this substance.


Research co-lead author Professor Baojiu Li, of Durham University’s Institute for Computational Cosmology, said: «In General Relativity, scientists account for the accelerated expansion of the universe by introducing a mysterious form of matter called dark energy — the simplest form of which may be a cosmological constant, whose density is a constant in space and time.


«However, alternatives to a cosmological constant which explain the accelerated expansion by modifying the law of gravity, like f(R) gravity, are also widely considered given how little is known about dark energy.»


The Durham researchers expect their findings can be tested through observations using the Square Kilometre Array (SKA) telescope, based in Australia and South Africa, which is due to begin observations in 2020.


SKA will be the world’s largest radio telescope and aims to challenge Einstein’s theory of General Relativity, look at how the first stars and galaxies formed after the Big Bang, and help scientists to understand the nature or dark energy.


The findings are published in Nature Astronomy.


Source: Durham University [July 08, 2019]



TANN



Archive


Instability in Antarctic ice projected to make sea level rise rapidly

Images of vanishing Arctic ice and mountain glaciers are jarring, but their potential contributions to sea level rise are no match for Antarctica’s, even if receding southern ice is less eye-catching. Now, a study says that instability hidden within Antarctic ice is likely to accelerate its flow into the ocean and push sea level up at a more rapid pace than previously expected.











Instability in Antarctic ice projected to make sea level rise rapidly
Part of Thwaites Glacier crumbles into the ocean. It is part of the normal life of a glacier, but the rate
of ice flow into the ocean of some Antarctic glaciers has markedly accelerated, raising concerns
[Credit: NASA/OIB Jeremy Harbeck]

In the last six years, five closely observed Antarctic glaciers have doubled their rate of ice loss, according to the National Science Foundation. At least one, Thwaites Glacier, modeled for the new study, may be in danger of succumbing to this instability, a volatile process that pushes ice into the ocean fast.


How much ice the glacier will shed in coming 50 to 800 years can’t exactly be projected due to unpredictable fluctuations in climate and the need for more data. But researchers at the Georgia Institute of Technology, NASA Jet Propulsion Laboratory, and the University of Washington have factored the instability into 500 ice flow simulations for Thwaites with refined calculations.


The scenarios diverged strongly from each other but together pointed to the eventual triggering of the instability, which will be described in the question and answer section below. Even if global warming were to later stop, the instability would keep pushing ice out to sea at an enormously accelerated rate over the coming centuries.


And this is if ice melt due to warming oceans does not get worse than it is today. The study went with present-day ice melt rates because the researchers were interested in the instability factor in itself.


Glacier tipping point


«If you trigger this instability, you don’t need to continue to force the ice sheet by cranking up temperatures. It will keep going by itself, and that’s the worry,» said Alex Robel, who led the study and is an assistant professor in Georgia Tech’s School of Earth and Atmospheric Sciences. «Climate variations will still be important after that tipping point because they will determine how fast the ice will move.»











Instability in Antarctic ice projected to make sea level rise rapidly
Thwaites Glacier’s outer edge. As the glacier flows into the ocean, it becomes sea ice and drives up sea level.
Thwaites Glacier ice is flowing particularly fast, and some researchers believe it may have already tipped
 into instability or be near that point, though this has not yet been established
[Credit: NASA/James Yungel]

«After reaching the tipping point, Thwaites Glacier could lose all of its ice in a period of 150 years. That would make for a sea level rise of about half a meter (1.64 feet),» said NASA JPL scientist Helene Seroussi, who collaborated on the study. For comparison, current sea level is 20 cm (nearly 8 inches) above pre-global warming levels and is blamed for increased coastal flooding.


The researchers published their study in the journal the Proceedings of the National Academy of Sciences. The research was funded by the National Science Foundation and NASA.


The study also showed that the instability makes forecasting more uncertain, leading to the broad spread of scenarios. This is particularly relevant to the challenge of engineering against flood dangers.


«You want to engineer critical infrastructure to be resistant against the upper bound of potential sea level scenarios a hundred years from now,» Robel said. «It can mean building your water treatment plants and nuclear reactors for the absolute worst-case scenario, which could be two or three feet of sea level rise from Thwaites Glacier alone, so it’s a huge difference.»


Q&A


Why is Antarctic ice the big driver of sea level rise?


Arctic sea ice is already floating in water. Readers will likely remember that 90% of an iceberg’s mass is underwater and that when its ice melts, the volume shrinks, resulting in no change in sea level.











Instability in Antarctic ice projected to make sea level rise rapidly
Changes in the Antarctic ice sheet’s contribution to global sea level, 1992 to 2017
[Credit IMBIE (NASA/ESA)]

But when ice masses long supported by land, like mountain glaciers, melt, the water that ends up in the ocean adds to sea level. Antarctica holds the most land-supported ice, even if much of that land is seabed holding up just part of the ice’s mass, while water holds up part of it. Also, Antarctica is an ice leviathan.


«There’s almost eight times as much ice in the Antarctic ice sheet as there is in the Greenland ice sheet and 50 times as much as in all the mountain glaciers in the world,» Robel said.


What is that ‘instability’ underneath the ice?


The line between where the ice sheet rests on the seafloor and where it extends over water is called the grounding line. In spots where the bedrock underneath the ice behind the grounding line slopes down, deepening as it moves inland, the instability can kick in.


On deeper beds, ice moves faster because water is giving it a little more lift. Also, warmer ocean water hollows out the bottom of the ice, adding a little more water to the ocean. More importantly, the ice above the hollow loses land contact and flows faster out to sea.











Instability in Antarctic ice projected to make sea level rise rapidly
Ice melt at the grounding line contributes to seawater and thus sea levels, but the larger effect is to send more ice
above it out into the water, where it also drives up sea level. When sea bottom behind the grounding line,
under the ice, slopes downward going inland, it exacerbates the process, which can become unstable,
perpetually pushing ice out to sea [Credit: antarcticglaciers.org]

«Once ice is past the grounding line and just over water, it’s contributing to sea level because buoyancy is holding it up more than it was,» Robel said. «Ice flows out into the floating ice shelf and melts or breaks off as icebergs.»


«The process becomes self-perpetuating,» Seroussi said, describing why it is called «instability.»


How did the researchers integrate instability into sea level forecasting?


The researchers borrowed math from statistical physics that calculate what random variables do to predictability in a physical system, like ice flow, acted upon by outside forces, like temperature changes. They applied the math to simulations of possible future fates of marine glaciers like Thwaites Glacier.


They made an added surprising discovery. Normally, when climate conditions fluctuate strongly, Antarctic ice evens out the effects. Ice flow may increase but gradually, not wildly, but the instability produced the opposite effect in the simulations.


«The system didn’t damp out the fluctuations, it actually amplified them. It increased the chances of rapid ice loss,» Robel said.


Credit: Georgia Institute of Technology      


How rapid is ‘rapid’ sea level rise and when will we feel it?


The study’s time scale was centuries, as is common for sea level studies. In the simulations, Thwaites Glacier colossal ice loss kicked in after 600 years, but it could come sooner.


«It could happen in the next 200 to 600 years. It depends on the bedrock topography under the ice, and we don’t know it in great detail yet,» Seroussi said.


So far, Antarctica and Greenland have lost a small fraction of their ice, but already, shoreline infrastructures face challenges from increased tidal flooding and storm surges. Sea level is expected to rise by up to two feet by the end of this century.


For about 2,000 years until the late 1800s, sea level held steady, then it began climbing, according to the Smithsonian Institution. The annual rate of sea level rise has roughly doubled since 1990.


Author: Ben Brumfield | Source: Georgia Institute of Technology [July 08, 2019]



TANN



Archive


Crew Configures Hardware to Monitor Brain and Radiation Exposure in Space


ISS — Expedition 60 Mission patch.


July 10, 2019


The Expedition 60 crew configured a variety of science hardware today monitoring the brain and radiation exposure. The orbital residents also had a steady day of safety gear checks and lab maintenance on the International Space Station.


Astronauts experience blood flow changes caused by living in microgravity that may cause lightheadedness or fainting upon return to Earth. The Cerebral Autoregulation investigation is measuring the waveforms of these blood flows to understand blood pressure regulation in space. Flight Engineer Nick Hague set up the experiment hardware this morning that may help doctors treat and prevent these symptoms.



Image above: The International Space Station was orbiting 258 miles above the Bay of Bengal during an orbital nighttime when this photograph was taken of Earth’s luminous atmospheric glow back-dropped by the tranquil Milky Way. Image Credit: NASA.


Hague next assembled hardware for a high definition camera that will be installed outside the station on an upcoming spacewalk. He and NASA astronaut Christina Koch also installed communication cables and conducted voice checks to support the arrival of future commercial crew vehicles.



International Space Station (ISS)

Radiation exposure is another concern for crewmembers working in space for months or years at a time. Koch handed a set of dosimeters, or radiation detectors, to Commander Alexey Ovchinin during the afternoon for installation on the Russian side of the orbiting lab. Several studies are monitoring neutron radiation and the variation in the radiation environment as the station orbits Earth.


Koch started her morning inspecting breathing masks and fire extinguishers. She checked the emergency equipment for correct pressure measurements and any signs of physical damage on hoses and bottles. Ovchinin continued the replacement of more Russian life support system components during his morning.


Related links:


Expedition 60: https://www.nasa.gov/mission_pages/station/expeditions/expedition60/index.html


Cerebral Autoregulation: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1938


Neutron radiation: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/search.html?#q=radi-n&i=&p=&c=&g=&s=


Variation in the radiation environment: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/search.html?#q=matroyshka&i=&p=&c=&g=&s=


Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html


International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html


Images (mentioned), Text, Credits: NASA/Mark Garcia.


Best regards, Orbiter.chArchive link


Climate change and deforestation together push tropical species towards extinction

Only 38 per cent of tropical forest is ‘wildlife friendly’ as a result of deforestation, increasing the likelihood that vulnerable species will go extinct, say scientists.











Climate change and deforestation together push tropical species towards extinction
Nevado del Ruiz, Central Colombian Andes [Credit: Professor David Edwards]

Researchers from the University of Sheffield and University of York have discovered how deforestation and climate change — two of the biggest drivers of species’ extinction — interact with each other to magnify their effects.


For millennia, wildlife around the world has moved up and down mountains and towards or away from the equator to cope with changes in the Earth’s temperature. The deforestation of tropical forests is creating a patchwork landscape where natural habitat is disconnected and confined to smaller spaces between a mass of farmland.


The research found that most tropical forest habitat is currently too disconnected to provide pathways to cooler climates, meaning wildlife will struggle to escape the impacts of climate change.


Tropical deforestation between 2000 — 2012 led to a vast amount of forest area, bigger than India, losing its ability to link tropical wildlife with a habitat that would protect them from rising temperatures. Today, only 38 per cent of tropical forest allows resident wildlife to avoid climate warming by moving uphill or towards the poles.


Senior author of the study, Professor David Edwards from the University of Sheffield, said: «The speed and severity with which the ability of plants and wildlife to track their optimal climates has been severed is truly shocking.


«In considering what we can do to solve this problem, we urgently need to fund mechanisms to stop tropical forest loss whilst also investing in reforestation in places where deforestation has already been most severe.


«The time to act is now and failure to do so will have catastrophic effects for tropical biodiversity over the coming century.»


This loss of forest means that if species move as far as possible to the coldest places along connected temperature gradients, then under severe warming scenarios species would still, on average, suffer 2.6 degrees Celsius in warming.


Dr Rebecca Senior, who carried out this work whilst at the University of Sheffield’s Department of Animal and Plant Sciences, said: «Our findings are cause for concern. We know that a huge amount of tropical rainforest has been and continues to be converted, but also that habitat loss is not the only threat to the natural world.


«Our research is the first to investigate this interaction between habitat loss and climate change at such a large scale and over time. Almost everywhere is getting warmer and for tropical species sensitive to these increasing temperatures, the lack of escape routes to cooler habitats means that warming will likely result in national and global extinctions of vulnerable species.»


The research has been published in Nature Climate Change.


Source: University of Sheffield [July 08, 2019]



TANN



Archive


Breaching a ‘carbon threshold’ could lead to mass extinction

In the brain, when neurons fire off electrical signals to their neighbours, this happens through an «all-or-none» response. The signal only happens once conditions in the cell breach a certain threshold.  Now an MIT researcher has observed a similar phenomenon in a completely different system: Earth’s carbon cycle.











Breaching a 'carbon threshold' could lead to mass extinction
When carbon emissions pass a critical threshold, it can trigger a spike-like reflex in the carbon cycle,
 in the form of severe ocean acidification that lasts for 10,000 years [Credit: MIT]

Daniel Rothman, professor of geophysics and co-director of the Lorenz Center in MIT’s Department of Earth, Atmospheric and Planetary Sciences, has found that when the rate at which carbon dioxide enters the oceans pushes past a certain threshold — whether as the result of a sudden burst or a slow, steady influx — the Earth may respond with a runaway cascade of chemical feedbacks, leading to extreme ocean acidification that dramatically amplifies the effects of the original trigger.


This global reflex causes huge changes in the amount of carbon contained in the Earth’s oceans, and geologists can see evidence of these changes in layers of sediments preserved over hundreds of millions of years.


Rothman looked through these geologic records and observed that over the last 540 million years, the ocean’s store of carbon changed abruptly, then recovered, dozens of times in a fashion similar to the abrupt nature of a neuron spike. This «excitation» of the carbon cycle occurred most dramatically near the time of four of the five great mass extinctions in Earth’s history.


Scientists have attributed various triggers to these events, and they have assumed that the changes in ocean carbon that followed were proportional to the initial trigger — for instance, the smaller the trigger, the smaller the environmental fallout.


But Rothman says that’s not the case. It didn’t matter what initially caused the events; for roughly half the disruptions in his database, once they were set in motion, the rate at which carbon increased was essentially the same. Their characteristic rate is likely a property of the carbon cycle itself — not the triggers, because different triggers would operate at different rates.


What does this all have to do with our modern-day climate? Today’s oceans are absorbing carbon about an order of magnitude faster than the worst case in the geologic record — the end-Permian extinction. But humans have only been pumping carbon dioxide into the atmosphere for hundreds of years, versus the tens of thousands of years or more that it took for volcanic eruptions or other disturbances to trigger the great environmental disruptions of the past. Might the modern increase of carbon be too brief to excite a major disruption?


According to Rothman, today we are «at the precipice of excitation,» and if it occurs, the resulting spike — as evidenced through ocean acidification, species die-offs, and more — is likely to be similar to past global catastrophes.


«Once we’re over the threshold, how we got there may not matter,» says Rothman, who is publishing his results this week in the Proceedings of the National Academy of Sciences. «Once you get over it, you’re dealing with how the Earth works, and it goes on its own ride.»


A carbon feedback


In 2017, Rothman made a dire prediction: By the end of this century, the planet is likely to reach a critical threshold, based on the rapid rate at which humans are adding carbon dioxide to the atmosphere. When we cross that threshold, we are likely to set in motion a freight train of consequences, potentially culminating in the Earth’s sixth mass extinction.


Rothman has since sought to better understand this prediction, and more generally, the way in which the carbon cycle responds once it’s pushed past a critical threshold. In the new paper, he has developed a simple mathematical model to represent the carbon cycle in the Earth’s upper ocean and how it might behave when this threshold is crossed.


Scientists know that when carbon dioxide from the atmosphere dissolves in seawater, it not only makes the oceans more acidic, but it also decreases the concentration of carbonate ions. When the carbonate ion concentration falls below a threshold, shells made of calcium carbonate dissolve. Organisms that make them fare poorly in such harsh conditions.


Shells, in addition to protecting marine life, provide a «ballast effect,» weighing organisms down and enabling them to sink to the ocean floor along with detrital organic carbon, effectively removing carbon dioxide from the upper ocean. But in a world of increasing carbon dioxide, fewer calcifying organisms should mean less carbon dioxide is removed.


«It’s a positive feedback,» Rothman says. «More carbon dioxide leads to more carbon dioxide. The question from a mathematical point of view is, is such a feedback enough to render the system unstable?»


«An inexorable rise»


Rothman captured this positive feedback in his new model, which comprises two differential equations that describe interactions between the various chemical constituents in the upper ocean. He then observed how the model responded as he pumped additional carbon dioxide into the system, at different rates and amounts.


He found that no matter the rate at which he added carbon dioxide to an already stable system, the carbon cycle in the upper ocean remained stable. In response to modest perturbations, the carbon cycle would go temporarily out of whack and experience a brief period of mild ocean acidification, but it would always return to its original state rather than oscillating into a new equilibrium.


When he introduced carbon dioxide at greater rates, he found that once the levels crossed a critical threshold, the carbon cycle reacted with a cascade of positive feedbacks that magnified the original trigger, causing the entire system to spike, in the form of severe ocean acidification. The system did, eventually, return to equilibrium, after tens of thousands of years in today’s oceans — an indication that, despite a violent reaction, the carbon cycle will resume its steady state.


This pattern matches the geological record, Rothman found. The characteristic rate exhibited by half his database results from excitations above, but near, the threshold. Environmental disruptions associated with mass extinction are outliers — they represent excitations well beyond the threshold. At least three of those cases may be related to sustained massive volcanism.


«When you go past a threshold, you get a free kick from the system responding by itself,» Rothman explains. «The system is on an inexorable rise. This is what excitability is, and how a neuron works too.»


Although carbon is entering the oceans today at an unprecedented rate, it is doing so over a geologically brief time. Rothman’s model predicts that the two effects cancel: Faster rates bring us closer to the threshold, but shorter durations move us away. Insofar as the threshold is concerned, the modern world is in roughly the same place it was during longer periods of massive volcanism.


In other words, if today’s human-induced emissions cross the threshold and continue beyond it, as Rothman predicts they soon will, the consequences may be just as severe as what the Earth experienced during its previous mass extinctions.


«It’s difficult to know how things will end up given what’s happening today,» Rothman says. «But we’re probably close to a critical threshold. Any spike would reach its maximum after about 10,000 years. Hopefully that would give us time to find a solution.»


Author: Jennifer Chu | Source: Massachusetts Institute of Technology [July 08, 2019]



TANN



Archive


Live fast and die young, or play the long game? Scientists map 121 animal life cycles

Scientists have pinpointed the «pace» and «shape» of life as the two key elements in animal life cycles that affect how different species get by in the world. Their findings, which come from a detailed assessment of 121 species ranging from humans to sponges, may have important implications for conservation strategies and for predicting which species will be the winners and losers from the global environment crisis.











Live fast and die young, or play the long game? Scientists map 121 animal life cycles
The pace and shape of life varies hugely in the animal kingdom
[Credit: Kevin Healy]

«Pace of life» relates to how fast animals reach maturity, how long they can expect to live, and the rate at which they can replenish a population with offspring. «Shape of life», meanwhile, relates to how an animal’s chance of breeding or dying is spread out across its lifespan.


The scientists, from the National University of Ireland Galway, Trinity College Dublin, Oxford University, the University of Southampton, and the University of Southern Denmark, have published their work in leading journal, Nature Ecology & Evolution.


The wide range of animal life cycles


Animal life cycles vary to a staggering degree. Some animals, such as the turquoise killifish (a small fish that can complete its life cycle in 14 days) grow fast and die young, while others, like the Greenland shark, (a fish that glides around for up to 500 years), grow slowly and have extraordinarily long lifespans.


Similarly, the spread of death and reproduction across animal life cycles also varies greatly. Salmon, for example, spawn over a short period of time with the probability of dying being particularly high both at the start of their life cycle and when they reproduce. Fulmars and some other sea birds, on the other hand, have wider time periods of reproduction and face relatively similar chances of dying throughout their lives.


Humans and Asian elephants have long lifespans and face a relatively low risk of mortality until later ages but have a fairly narrow age range for reproduction because they have long juvenile periods and live a long time after the reproductive part of their life-cycles. Both species share a similar lifespan with the Australian freshwater crocodile, but the crocodile has a completely different reproductive strategy — its reproduction is spread relatively evenly throughout its lifespan but its young have a low chance of reaching adulthood and reproducing.


The puzzle of different life cycles — why so many?


Why animal life cycles vary so much has long been an important puzzle that scientists have sought to solve. Among the reasons are that understanding why animals age, reproduce and grow at different rates may 1) help shed light on the evolution of aging itself, and 2) help identify how species will respond to global environmental change.


In their study, the scientists used population data to compare detailed life cycles for species ranging from sponges to corals, salmon to turtles, and vultures to humans. By mapping 121 life cycles, the scientists noticed that certain animal ecologies and physiologies were associated with certain life cycles.


Dr Kevin Healy who conducted the research at Trinity and is now Lecturer of Zoology at the National University of Ireland Galway, is the lead author of the study. He said: «When we mapped out the range of life cycles in the animal kingdom we saw that they follow general patterns. Whether you are a sponge, a fish or a human, your life cycle can, in general, be described by two things — how fast you live and how your reproduction and chance of dying is spread out across your lifespan.»


«As we expected, species with low metabolic rates and slow modes-of-life were associated with slower life cycles. This makes sense; if you don’t burn much energy per second, you are restricted in how fast you can grow. Similarly, if you are an animal that doesn’t move around a lot, such as a sponge or a fish that lives on the sea bed, playing a longer game in terms of your pace of life makes sense as you may need to wait for food to come to you.»


Conservation implications


The scientists also investigated whether certain life cycles made animals more susceptible to ecological threats, by looking for associations between an animal’s life cycle and its position on the IUCN red list of endangered species.


Professor of Zoology and Head of the Zoology Department at Trinity, Yvonne Buckley, is co-senior author of the research. She said: «We found that extinction risks were not confined to particular types of life history for the 121 species. Despite these animals having very different ways of maintaining their populations, they faced similar levels of threat.»


«Populations of a particular species, like the Chinook salmon or Freshwater crocodile, vary more in how mortality and reproduction are spread across their life-spans than they vary in their pace of life. This is important for the animal populations that we need to conserve as it suggests it may be wiser to consider actions that boost reproduction and/or impart bigger effects on the periods of the life cycles when mortality and reproduction are more likely — rather than simply aiming to extend the lifespans of these animals.»


Associate Professor in Ecology at the University of Oxford, Dr Rob Salguero-Gómez, is also co-senior author of the research. He said: «This comparative work, which builds on previous research we have developed testing basic assumptions of how life structures the Plant Kingdom, highlights important commonalities in the ways that both animals and plants go about making a living and adapting to different environments. Indeed, classical works in life history theory predicted a single way to structure life strategies. Our work with plants and now here with animals shows the range of possibilities is much wider than previously believed.»


«The unparalleled wealth of animal demographic schedules used in this research produced by an initiative led by Assoc. Prof Salguero-Gómez & co-author Assoc. Prof. Owen Jones, opens up new exciting ways to explore what are the most common strategies used by different species to thrive in their environments, but also to use demographic models to make predictions about what species will be the winners and losers of climate change.»


Source: Trinity College Dublin [July 08, 2019]



TANN



Archive


The parallel ecomorph evolution of scorpionflies: The evidence is in the DNA

With little cases of ethanol to preserve tissue samples for total genomic DNA analysis, a trio covered much ground in the mountains of Japan and Korea to elucidate the evolution of the scorpionfly. The rugged scientists set out to use molecular phylogenetic analysis to show that the «alpine» type of scorpionfly and «general» type must be different species. After all, the alpine type exhibit shorter wings than the general type, and alpine type females also have very dark and distinct markings on their wings. However, what they found in the DNA surprised them.











The parallel ecomorph evolution of scorpionflies: The evidence is in the DNA
Defying expectations, scorpionflies were found to have ecomorphed in parallel evolutions, independently adapting
along different high altitude locations in Japan. Using Bayesian simulations and molecular phylogenetic analysis,
scientists at the Institute for Mountain Science, Shinshu University were able to show the differing lineages of the
‘alpine’ and ‘general’ types of scorpionflies in their DNA, as well as time selective events such as glacial-interglacial
cycles and the uplifting of the Japanese mountains [Credit: © 2019, John Wiley and Sons Ltd]

Casually called the scorpionfly because the males have abdomens that curve upward and are shaped like the stinger of scorpions, the Panorpodes paradoxus do not sting. Tomoya Suzuki, postdoc research fellow of the Faculty of Science at Shinshu University, Suzuki’s father, expert of scorpionflies, Nobuo Suzuki, professor at the Japan Women’s College of Physical Education and Koji Tojo, professor at the only Institute for Mountain Science in Japan, Shinshu University, were able to indicate parallel evolutions of Japanese scorpionflies through Bayesian simulations and phylogenetic analyses.
Insects are among the most diverse organism on earth and many fall captive to their elegant beauty as did the scientists dedicated to their study. Insects are very adaptive to their habitat environments, making them excellent subjects to study ecology, evolution and morphology. Phylogenetics is the study of evolutionary history, often visualized in the form of ancestral trees. The team studied the Japanese scorpionfly by collecting samples of the Panorpodes paradoxus throughout Japan and parts of the Korean peninsula searching for samples in altitude of up to 3033 meters.


In a previous study, Professor Tojo was able to correlate plate tectonic geological events in Japan by studying the DNA of insects from a relatively small area of Nagano prefecture. By testing DNA, they discovered the different lineages align with how the land formations occurred in Japan, with some insect types having a more similar background to those on the Asian continent.











The parallel ecomorph evolution of scorpionflies: The evidence is in the DNA
A scheme of evolutionary history of the East Asian Panorpodes scorpionflies,
inferred from our study [Credit: © 2019, John Wiley and Sons Ltd]

The Japanese archipelago used to be a part of mainland East Asia. About 20 million years ago, the movement of the tectonic plates caused the Japanese land mass to tear away from the continent. By around 15 million years ago, the Japanese islands were completely detached and isolated from the mainland. Ancestral lineages of the Japanese Panorpodes therefore, diverged from the continental types around this time. The two major phenotypes of scorpionflies in Japan; the «alpine» type that live in higher altitudes and have shorter wings, and their «general» type counterparts. It is hypothesized that the shorter wings are better suited for the colder climate of higher elevations. The alpine and general types also have slightly different seasonal periods when they can be observed in the wild.
Through Bayesian simulations which are estimates through probability, the divergence time of the genealogical lineages were estimated. Simulations were run for over 100 million generations. The divergence time of the continental and Japanese Panorpodes was estimated to be 8.44 million years ago. The formation of the mountains in the Japanese Archipelago which began around 5 million years ago could be seen in the estimated evolution of the alpine type of P. paradoxus. Another estimated evolution time coincided with climate change cooling times. Cool weather is a tough environment for insects and serves as a genetic selection process. The cool glacial periods encouraged local adaptation of the scorpionflies in the northeast part of the island of Honshu.


With DNA tests of the various scorpionfly specimens, the group was able to show how the P. paradoxus «ecomorphed» or evolved to have forms and structural features adapted to their ecology. This parallel evolution started about 5 million years ago, when the mountain ranges in central Japan formed. Gene flow between the samples collected at different mountains were not detected, evidence of the parallel evolution. Interestingly however, gene flow between the general and alpine types might be happening, one indicator that they are not different species.











The parallel ecomorph evolution of scorpionflies: The evidence is in the DNA
(a) A graph indicating historic climate change, estimated based on deep sea benthic foraminiferal oxygen
 isotope levels. (b) The estimated result of the divergence time of Panorpodes scorpionflies was simulated.
(c) The result of historical dispersal pattern estimation by Bayesian stochastic search
variable selection [Credit: © 2019, John Wiley and Sons Ltd]

In conclusion, the alpine type and general type were not separate species as they suspected, but the alpine scorpionfly ecomorphed, explaining why they looked different. Through a next generation sequencer the team hope to elucidate the exact moment of difference. What sort of genetic basis underlies the alpine ecomorph? What type of genes emerged to facilitate the shortening of the wings?
The team hope to study the genetic basis for the ecomorph. To do so, Dr. Suzuki wishes to breed scorpionflies to further elucidate the differences in the gene expression from the alpine and general types. Breeding is necessary to perform the next generation sequencer but what the larva feeds on and other growing conditions remain a mystery.


The trio hope to unlock each of these steps to further identify the unknown aspects of the Japanese scorpionfly, as well as continue cutting edge research at the Institute for Mountain Science in Japan, Shinshu University, which is blessed to be surrounded by the Alps in the heart of Japan.


The findings appear in Molecular Ecology.


Source: Shinshu University [July 08, 2019]



TANN



Archive


Featured

    Солнечное затмение 14 декабря 2020 года  — полное  солнечное затмение  142  сароса , которое лучше всего будет видно в юго-восточной час...

Popular