пятница, 14 декабря 2018 г.

HiPOD (14 December 2018): Just Another Quiet Day on Mars   –…


HiPOD (14 December 2018): Just Another Quiet Day on Mars


   – This cluster of craters is located, ironically, in Utopia Planitia. (Alt: 290 km, less than 5 top to bottom and north is to the left.)


NASA/JPL/University of Arizona


First-ever look at complete skeleton of Thylacoleo, Australia’s extinct...

Thyalacoleo carnifex, the “marsupial lion” of Pleistocene Australia, was an adept hunter that got around with the help of a strong tail, according to a study in the open-access journal PLOS ONE by Roderick T. Wells of Flinders University and Aaron B. Camens of the South Australia Museum, Adelaide. These insights come after newly-discovered remains, including one nearly complete fossil specimen, allowed these researchers to reconstruct this animal’s entire skeleton for the first time.











First-ever look at complete skeleton of Thylacoleo, Australia's extinct 'marsupial lion'
Thylacoleo carnifex reconstructions: (A) Reconstruction of the skeleton of T. carnifex. (B) Body outline
based on examination of musculature evident in x-ray imaging of marsupials Vogelnest and Allen
[Credit: Wells et al., 2018]

A marsupial predator with an estimated weight of over 100kg, Thylacoleo was unlike any living animal, and paleontologists have long tried to interpret its lifestyle from incomplete remains. The new fossils, discovered in Komatsu Cave in Naracoorte and Flight Star Cave in the Nullarbor Plain, include the first known remains of the tail and collarbone of this animal. The authors used this new information to re-assess the biomechanics of Thylacoleo, and by comparing its anatomy to living marsupials, reach new conclusions about the biology and behavior of the “marsupial lion.”
The tail of Thylacoleo appears to have been stiff and heavily-muscled, probably allowing it to be used along with the hind limbs as a “tripod” to brace the body while freeing up the forelimbs for handling food or climbing, as many living marsupials do. The analysis suggests that Thylacoleo had a rigid lower back and powerful forelimbs anchored by strong collarbones, likely making it poorly suited for chasing prey, but well-adapted for ambush hunting and/or scavenging. These features also add to a list of evidence that Thylacoleo was an adept climber, perhaps of trees or steep-walled caverns. Among living marsupials, the anatomy of Thylacoleo appears most similar to the Tasmanian devil, a small carnivore that exhibits many of these inferred behaviors.
The authors add: “The extinct marsupial lion, Thylacoleo carnifex has intrigued scientists since it was first described in 1859 from skull and jaw fragments collected at Lake Colongulac in Victoria Australia and sent to Sir Richard Owen at the British Museum. Although Australia’s largest marsupial carnivore it retains many features indicative of its diprotodont herbivore ancestry and its niche has been a matter of considerable debate for more than 150yrs. Recent cave finds have for the first time enabled a description and reconstruction of the complete skeleton including the hitherto unrecognised tail and clavicles. In this study, Wells and Camens compare the Thylacoleo skeleton with those of range of extant Australian arboreal and terrestrial marsupials in which behaviour and locomotion is well documented. They conclude that the nearest structural and functional analogue to Thylacoleo is to be found in the unrelated and much smaller Tasmanian Devil, Sarcophilus harrisii, a scavenger /hunter. They draw attention to the prevalence of all age classes within individual cave deposits as suggestive of a high degree of sociality. Those ancestral features Thylacoleo shares with arboreal forms are equally well suited to climbing or grasping a prey. They conclude that Thylacoleo is a scavenger, ambush predator of large prey.”


Source: PLOS [December 12, 2018]



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Why deep oceans gave life to the first big, complex organisms

In the beginning, life was small. For billions of years, all life on Earth was microscopic, consisting mostly of single cells. Then suddenly, about 570 million years ago, complex organisms including animals with soft, sponge-like bodies up to a meter long sprang to life. And for 15 million years, life at this size and complexity existed only in deep water.











Why deep oceans gave life to the first big, complex organisms
More than 570 million years ago, in the Ediacaran period, complex organisms including soft-bodied animals
up to a metre long sprang to life in deep ocean waters [Credit: Ryan Somma/Flickr]

Scientists have long questioned why these organisms appeared when and where they did: in the deep ocean, where light and food are scarce, in a time when oxygen in Earth’s atmosphere was in particularly short supply. A new study from Stanford University, published in the peer-reviewed Proceedings of the Royal Society B, suggests that the more stable temperatures of the ocean’s depths allowed the burgeoning life forms to make the best use of limited oxygen supplies.


All of this matters in part because understanding the origins of these marine creatures from the Ediacaran period is about uncovering missing links in the evolution of life, and even our own species. “You can’t have intelligent life without complex life,” explained Tom Boag, lead author on the paper and a doctoral candidate in geological sciences at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth).


The new research comes as part of a small but growing effort to apply knowledge of animal physiology to understand the fossil record in the context of a changing environment. The information could shed light on the kinds of organisms that will be able to survive in different environments in the future.


“Bringing in this data from physiology, treating the organisms as living, breathing things and trying to explain how they can make it through a day or a reproductive cycle is not a way that most paleontologists and geochemists have generally approached these questions,” said Erik Sperling, senior author on the paper and an assistant professor of geological sciences.


Goldilocks and temperature change


Previously, scientists had theorized that animals have an optimum temperature at which they can thrive with the least amount of oxygen. According to the theory, oxygen requirements are higher at temperatures either colder or warmer than a happy medium. To test that theory in an animal reminiscent of those flourishing in the Ediacaran ocean depths, Boag measured the oxygen needs of sea anemones, whose gelatinous bodies and ability to breathe through the skin closely mimic the biology of fossils collected from the Ediacaran oceans.


“We assumed that their ability to tolerate low oxygen would get worse as the temperatures increased. That had been observed in more complex animals like fish and lobsters and crabs,” Boag said. The scientists weren’t sure whether colder temperatures would also strain the animals’ tolerance. But indeed, the anemones needed more oxygen when temperatures in an experimental tank veered outside their comfort zone.


Together, these factors made Boag and his colleagues suspect that, like the anemones, Ediacaran life would also require stable temperatures to make the most efficient use of the ocean’s limited oxygen supplies.


Refuge at depth


It would have been harder for Ediacaran animals to use the little oxygen present in cold, deep ocean waters than in warmer shallows because the gas diffuses into tissues more slowly in colder seawater. Animals in the cold have to expend a larger portion of their energy just to move oxygenated seawater through their bodies.


But what it lacked in useable oxygen, the deep Ediacaran ocean made up for with stability. In the shallows, the passing of the sun and seasons can deliver wild swings in temperature — as much as 10 degrees Celsius in the modern ocean, compared to seasonal variations of less than 1 degree Celsius at depths below one kilometer (.62 mile). “Temperatures change much more rapidly on a daily and annual basis in shallow water,” Sperling explained.


In a world with low oxygen levels, animals unable to regulate their own body temperature couldn’t have withstood an environment that so regularly swung outside their Goldilocks temperature.


The Stanford team, in collaboration with colleagues at Yale University, propose that the need for a haven from such change may have determined where larger animals could evolve. “The only place where temperatures were consistent was in the deep ocean,” Sperling said. In a world of limited oxygen, the newly evolving life needed to be as efficient as possible and that could only be achieved in the relatively stable depths. “That’s why animals appeared there,” he said.


Author: Josie Garthwaite | Source: Stanford’s School of Earth, Energy & Environmental Sciences [December 12, 2018]



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Fossils key to fulfilling Darwin’s 160-year-old prediction

A new study by researchers at the University of Salford has shown that fossils are likely to be key to fulfilling a prediction made by Charles Darwin more than 160 years ago.











Fossils key to fulfilling Darwin's 160-year-old prediction
The first evolutionary tree Charles Darwin ever drew, and a composite image of mammal diversity
[Credit: WikiCommons]

In an 1857 letter to Thomas Huxley, Darwin wrote “The time will come I believe when we shall have very fairly true genealogical trees of each great kingdom of nature.”


Since then, scientists have made enormous progress towards working out the evolutionary “Tree of Life”, but a major problem is that analyses based on anatomical features often suggest quite different relationships than do analyses based on the genome.


The new study, published in Proceedings of the Royal Society B, may have found the solution to this problem.


Lead author Dr. Robin Beck, said: “For mammals, there are some quite major disagreements about how they are related to each other, depending on whether you use anatomical or genomic data. This has led some people to suggest that anatomy is fundamentally unreliable for working out the evolutionary relationships of mammals, and perhaps of other groups as well.”


For example, molecular data indicates that rhinos are more closely related to hedgehogs than they are to elephants. The anatomical similarities between rhinos and elephants are the result of convergent evolution.


Beck and Baillie’s study shows that new fossil discoveries might be able to bridge the large anatomical “gap” between rhinos and hedgehogs and so help correctly determine their evolutionary relationships.”


To test this, Beck and his co-author, Ph.D. student Charles Baillie, invented a new method where they first predicted the anatomical features of fossil ancestors that should have existed if the genome-based phylogeny is correct, and then investigated the effect of adding these predicted ancestors into anatomy-based analyses.


Beck added: “We were quite surprised to find that predicted ancestors led to the anatomical analyses matching the genomic phylogeny almost exactly. So, it doesn’t look like there’s anything inherently unreliable about anatomical data – in principle at least.


“It may just be a case of going out and finding enough fossils!”


The same technique can be applied to any group of organisms, to test whether anatomical data is likely to correctly resolve their evolutionary relationships.


Source: University of Salford [December 13, 2018]



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Early animals: Death near the shoreline, not life on land

Our understanding of when the very first animals started living on land is helped by identifying trace fossils — the tracks and trails left by ancient animals — in sedimentary rocks that were deposited on the continents.











Early animals: Death near the shoreline, not life on land
Trackways [Credit: Anthony Shillito]

Geoscientists Anthony P. Shillito and Neil S. Davies of the University of Cambridge studied the site of what has widely been accepted as the earliest set of non-marine trackways, in Ordovician (ca. 455 million-year-old) strata from the Lake District, England.
What they discovered is that the trackways occur within volcanic ash that settled under water, and not within freshwater lake and sub-aerial sands (as previously thought). This means that the site is not the oldest evidence for animal communities on land, but instead “is actually a remarkable example of a ‘prehistoric Pompeii’,” says Shillito — a suite of rocks that preserve trails made by distressed and dying millipede-like arthropods as they were overcome by ash from volcanic events.











Early animals: Death near the shoreline, not life on land
Close-up of a looping millipede death-trail [Credit: Anthony Shillito]

Shillito and Davies directed their research at this site in particular because it seemed unusual — at every other known trackway site in the world the evidence for when animals came onto land dates to the latest Silurian (ca. 420 million years ago), so something about the Borrowdale site didn’t seem right. Further investigation proved that this was the case. In the course of their study, they found 121 new millipede trackways, all within volcanic ash with evidence for underwater or shoreline deposition.
Volcanic ash is known to cause mass death in some modern arthropod communities, particularly in water, because ash is so tiny it can get inside arthropod exoskeletons and stick to their breathing and digestive apparatus. Shilllito and Davies noticed that most of the trails were extremely tightly looping — a feature which is commonly associated with “death dances” in modern and ancient arthropods.











Early animals: Death near the shoreline, not life on land
Close-up of one of the millipede trackways [Credit: Anthony Shillito]

This study, published in Geology, overturns what is known about the earliest life on land and casts new light onto one of the key evolutionary events in the history of life on Earth. Shillito notes, “It reveals how even surprising events can be preserved in the ancient rock record, but — by removing the ‘earliest’ outlier of evidence — suggests that the invasion of the continents happened globally at the same time.”
Understanding how life engineered major evolutionary advances within environments, and the rate and impact of these advances on the functioning of the Earth system, provides vital context for understanding global change at the present day, and underlines the inseparable relationship between life and the planet.


Source: Geological Society of America [December 13, 2018]



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Pollen dispersal in traditional processing of buckwheat

Interpreting the source and significance of crop pollen in archaeological sites has always been a key issue in environmental and agricultural archaeology. With regards to this, the research team of Dr. Shang Xue from the Department of Archaeology and Anthropology of the University of Chinese Academy of Sciences, recently conducted a simulation study on the dispersal pattern of pollen in the traditional processing of buckwheat.


Pollen dispersal in traditional processing of buckwheat










Pollen dispersal in traditional processing of buckwheat
Pollens in the samples of buckwheat processing (400 times)(a) (b) Fagopyrum;
(c) Artemisia; (d) Chenopodiaceae [Credit: Science China Press]

Pollen, as an important index of agricultural archaeology, can be used to indicate the history of paleoenvironment change and ancient human agricultural activities. To date, the study of pollen dispersal is limited to the analysis of pollen rain in nature and in surface soil of farmland. The influence of the agricultural processing on pollen dispersal is rarely considered, became a handicap for a better understanding of the source and representation of crop pollen in archaeological sites.


As a kind of pseudocereal, buckwheat (Fagopyrum esculentum and F. tataricum) are short-season crops with drought-tolerant and barren-resistant features. Plant of buckwheat is widely cultivated and utilized in the world because of its low workforce requirements, wide geographical adaptability, strong resistance, and rich nutrient content.


Studies have suggested that buckwheat may have been domesticated on the edge of its wild ancestral distribution area in southwestern China. Later it was transmitted to the northern part, and then adapted to the arid environment, becoming a pan-Eurasian crop approximately 3000 BP.


Pollen of buckwheat is unique in shape. As a kind of cross-pollinated pollen, it has large grains, close propagation distance, small distribution area, as well as low representation. Therefore, there will be a clear indication about its source and relationship with the maternal plant region when the pollen grains of buckwheat were discovered. According to the above merits, the research on buckwheat pollen has been received much attention.











Pollen dispersal in traditional processing of buckwheat
The mean value and average percentage of buckwheat pollen released from pollen rain
in different processing stages [Credit: Science China Press]

On this basis, researchers examined pollen dispersal in the buckwheat traditional processing. Aerial pollen collection method was applied to collect pollen rains at various processing stages. Furthermore, the surface soil pollen analysis of buckwheat field and barren land, and the data on aerial pollen rain in the surrounding area were selected as control groups.


The result has shown that the content of buckwheat pollen in aerial pollen rain can reach more than 70% during the traditional processing, among which, the pollen release amount was the largest in the threshing and sieving stages, followed by the wind winnowing and harvesting stage.


Thus, the processing behavior of crops has a significant impact on the distribution of crop pollen in residential areas. The results can help us interpret the distribution patterns and contribution rates of pollen during buckwheat processing. A high proportion of crop pollen can indicate not only the cultivation behavior, but also the processing behavior of humans. This research provides a scientific and experimental basis for identifying the crop processing remains in archaeological sites as well as assessing the intensity and impact of agricultural activities.


As a basic research, this research provides new concepts for the application of crop pollen dispersal in agricultural archaeology and new findings on buckwheat pollen research, which has certain interdisciplinary and scientific significance.


The research paper has been published online in Science China: Earth Sciences.


Source: Science China Press [December 13, 2018]



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Research team discovers oldest known plant virus at ancient settlement

Researchers studying ancient corncobs found at a Native American archaeological site have recovered a 1,000-year-old virus, the oldest plant virus ever reported.











Research team discovers oldest known plant virus at ancient settlement
Examining 1,000-year-old corn cobs from an ancient ruin in Arizona, researchers found a previously
unknown virus – the oldest plant virus ever reported [Credit: Roossinck Laboratory, Penn State]

Only a few RNA viruses had been discovered previously from archaeological samples, the oldest dating from about 750 years ago. The new discovery came as the research team examined ancient plant material from Antelope House, an Ancestral Puebloan ruin located at Canyon de Chelly National Monument, Arizona.


The Ancestral Puebloans who lived in the canyon planted crops such as maize, beans and squash. During the excavation of Antelope House by the National Park Service in the 1970s, more than two tons of plant refuse, in highly recognizable form, were recovered.


“It’s clear from these remains that maize was a major food source for the inhabitants,” said lead researcher Marilyn Roossinck, professor of plant pathology and environmental microbiology, College of Agricultural Sciences, Penn State. “The maize remnants recovered at Antelope House consisted of cobs, ears with kernels, individual kernels, husks, leaves, shanks, stem portions and tassels.”


Using carbon 14 dating, researchers confirmed that the age of the ancient samples was about 1,000 years old. While analyzing cobs, the scientists isolated three nearly complete genomes of a previously unknown virus of the family Chrysoviridae, which infect plants and fungi.











Research team discovers oldest known plant virus at ancient settlement
Ancient inhabitants of the Antelope House ruin, in Arizona’s Canyon de Chelly National Monument,
grew crops such as maize, beans and squash [Credit: National Parks Service]

The researchers, who report their findings in the current issue of the Journal of Virology, noted that chrysoviruses are persistent plant viruses that are transmitted from generation to generation through seeds and can remain in their hosts for very long time periods. Persistent viruses typically do not cause disease and rarely are detected. This is the first chrysovirus described from maize, Roossinck noted.


“When we analyzed modern corn samples, we found the same chrysovirus with only about 3 percent divergence from the ancient samples,” she said. “Most RNA viruses, with short generation times and error-prone replication, evolve rapidly. However, persistent viruses have very stable genomes.”


Roossinck said the most interesting aspect of the findings for the team is that the virus has been maintained in corn for so long.


“That implies that the virus might confer some potential benefit to the plant, but we haven’t shown that yet,” she said.


Source: Penn State [December 13, 2018]



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2018 December 14 Swimming on Jupiter Image Credit: NASA,…


2018 December 14


Swimming on Jupiter
Image Credit: NASA, JPL-Caltech, SwRI, MSSS; Processing: Brian Swift, Sean Doran


Explanation: On October 29, the Juno spacecraft once again dove near the turbulent Jovian cloud tops. Its 16th orbital closest approach or perijove passage, brought Juno within 3,500 kilometers of the Solar System’s largest planetary atmosphere. These frames, recorded by JunoCam while the spacecraft cruised 20 – 50 thousand kilometers above the planet’s middle southern latitudes, seem to follow a swirling cloud shaped remarkably like a dolphin. Swimming along Jupiter’s darker South South Temperate Belt, this dolphin is itself planet-sized though, some thousands of kilometers across. Juno’s next perijove passage will be December 21.


∞ Source: apod.nasa.gov/apod/ap181214.html


NASA Science Show & Tell

This week, we’re at one of the biggest science conferences in the country, where our scientists are presenting new results from our missions and projects. It’s called the American Geophysical Union’s Fall Meeting.


Here are a few of the things we shared this week…


image

The Sun


A few months into its seven-year mission, Parker Solar Probe has already flown far closer to the Sun than any spacecraft has ever gone. The data from this visit to the Sun has just started to come back to Earth, and scientists are hard at work on their analysis.


image

Parker Solar Probe sent us this new view of the Sun’s outer atmosphere, the corona. The image was taken by the mission’s WISPR instrument on Nov. 8, 2018, and shows a coronal streamer seen over the east limb of the Sun. Coronal streamers are structures of solar material within the Sun’s atmosphere, the corona, that usually overlie regions of increased solar activity. The fine structure of the streamer is very clear, with at least two rays visible. Parker Solar Probe was about 16.9 million miles from the Sun’s surface when this image was taken. The bright object near the center of the image is Mercury, and the dark spots are a result of background correction.


Hurricane Maria


Using a satellite view of human lights, our scientists watched the lights go out in Puerto Rico after Hurricane Maria. They could see the slow return of electricity to the island, and track how rural and mountainous regions took longer to regain power.


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In the spring, a team of scientists flew a plane over Puerto Rico’s forests, using a laser instrument to measure how trees were damaged and how the overall structure of the forests had changed.


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Earth’s Ice


Our scientists who study Antarctica saw some surprising changes to East Antarctica. Until now, most of the continent’s melting has been on the peninsula and West Antarctica, but our scientists have seen glaciers in East Antarctica lose lots of ice in the last few years.


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Our ICESat-2 team showed some of their brand new data. From the changing height of Antarctic ice to lagoons off the coast of Mexico, the little satellite has spent its first few months measuring our planet in 3D. The laser pulses even see individual ocean waves, in this graph.


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Scientists are using our satellite data to track Adélie penguin populations, by using an unusual proxy – pictures of their poop! Penguins are too small to be seen by satellites, but they can see large amounts of their poop (which is pink!) and use that as a proxy for penguin populations.


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Asteroid Bennu


Our OSIRIS-REx mission recently arrived at its destination, asteroid Bennu. On approach, data from the spacecraft’s spectrometers revealed chemical signatures of water trapped in clay minerals.  While Bennu itself is too small to have ever hosted liquid water, the finding indicates that liquid water was present at some time on Bennu’s parent body, a much larger asteroid.



We also released a new, detailed shape model of Bennu, which is very similar to our ground-based observations of Bennu’s shape. This is a boon to ground-based radar astronomy since this is our first validation of the accuracy of the method for an asteroid! One change from the original shape model is the size of the large boulder near Bennu’s south pole, nicknamed “Benben.” The boulder is much bigger than we thought and overall, the quantity of boulders on the surface is higher than expected. Now the team will make further observations at closer ranges to more accurately assess where a sample can be taken on Bennu to later be returned to Earth.


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Jupiter


The Juno mission celebrated it’s 16th science pass of #Jupiter, marking the halfway point in data collection of the prime mission. Over the second half of the prime mission — science flybys 17 through 32 — the spacecraft will split the difference, flying exactly halfway between each previous orbit. This will provide coverage of the planet every 11.25 degrees of longitude, providing a more detailed picture of what makes the whole of Jupiter tick.


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Mars


The Mars 2020 team had a workshop to discuss the newly announced landing site for our next rover on the Red Planet. The landing site…Jezero Crater! The goal of Mars 2020 is to learn whether life ever existed on Mars. It’s too cold and dry for life to exist on the Martian surface today. But after Jezero Crater formed billions of years ago, water filled it to form a deep lake about the same size as Lake Tahoe. Eventually, as Mars’ climate changed, Lake Jezero dried up. And surface water disappeared from the planet.



Interstellar Space


Humanity now has two interstellar ambassadors. On Nov. 5, 2018, our Voyager 2 spacecraft left the heliosphere — the bubble of the Sun’s magnetic influence formed by the solar wind. It’s only the second-ever human-made object to enter interstellar space, following its twin, Voyager 1, that left the heliosphere in 2012.


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Scientists are especially excited to keep receiving data from Voyager 2, because — unlike Voyager 1 — its plasma science instrument is still working. That means we’ll learn brand-new information about what fills the space between the stars.


Learn more about NASA Science at science.nasa.gov


Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com 


Italians are interesting people (Raveane et al. 2018 preprint)

Over at bioRxiv at this LINK. As far as I can see from skimming through the preprint, it’s a thorough effort with conclusions that make good sense. But, needless to say, it’ll be very useful to plug the dataset from this study into the Global25 to see what these new Italian samples are really made of. Here’s the abstract, emphasis is mine.



European populations display low genetic diversity as the result of long term blending of the small number of ancient founding ancestries. However it is still unclear how the combination of ancient ancestries related to early European foragers, Neolithic farmers and Bronze Age nomadic pastoralists can fully explain genetic variation across Europe. Populations in natural crossroads like the Italian peninsula are expected to recapitulate the overall continental diversity, but to date have been systematically understudied. Here we characterised the ancestry profiles of modern-day Italian populations using a genome-wide dataset representative of modern and ancient samples from across Italy, Europe and the rest of the world. Italian genomes captured several ancient signatures, including a non-steppe related substantial ancestry contribution ultimately from the Caucasus. Differences in ancestry composition as the result of migration and admixture generated in Italy the largest degree of population structure detected so far in the continent and shaped the amount of Neanderthal DNA present in modern-day populations.






Raveane et al., Population structure of modern-day Italians reveals patterns of ancient and archaic ancestries in Southern Europe, Posted December 13, 2018, bioRxiv, doi: https://doi.org/10.1101/494898
See also…
Greeks in a Longobard cemetery
Migration of the Bell Beakers—but not from Iberia (Olalde et al. 2018)
Late PIE ground zero now obvious; location of PIE homeland still uncertain, but…

Source


Preparing for Discovery With NASA’s Parker Solar Probe


NASA – Parker Solar Probe patch.


Dec. 13, 2018


Weeks after Parker Solar Probe made the closest-ever approach to a star, the science data from the first solar encounter is just making its way into the hands of the mission’s scientists. It’s a moment many in the field have been anticipating for years, thinking about what they’ll do with such never-before-seen data, which has the potential to shed new light on the physics of our star, the Sun.


On Dec. 12, 2018, four such researchers gathered at the fall meeting of the American Geophysical Union in Washington, D.C., to share what they hope to learn from Parker Solar Probe.



Image above: Illustration of Parker Solar Probe at the Sun. Image Credit: NASA’s Goddard Space Flight Center.


“Heliophysicists have been waiting more than 60 years for a mission like this to be possible,” said Nicola Fox, director of the Heliophysics Division at NASA Headquarters in Washington. Heliophysics is the study of the Sun and how it affects space near Earth, around other worlds and throughout the solar system. “The solar mysteries we want to solve are waiting in the corona.”


From Oct. 31 to Nov. 11, 2018, Parker Solar Probe completed its first solar encounter phase, speeding through the Sun’s outer atmosphere — the corona — and collecting unprecedented data with four suites of cutting-edge instruments.


Parker Solar Probe is named for Eugene Parker, the physicist who first theorized the existence of the solar wind — the Sun’s constant outpouring of material — in 1958.


“This is the first NASA mission to be named for a living individual,” said Fox. “Gene Parker’s revolutionary paper predicted the heating and expansion of the corona and solar wind. Now, with Parker Solar Probe we are able to truly understand what drives that constant flow out to the edge of the heliosphere.”


Our Sun’s influence is far-reaching. The solar wind, its outflow of material, fills up the inner part of our solar system, creating a bubble that envelops the planets and extends far past the orbit of Neptune. Embedded in its energized particles and solar material, the solar wind carries with it the Sun’s magnetic field. Additional one-off eruptions of solar material called coronal mass ejections also carry this solar magnetic field — and in both cases, this magnetized material can interact with Earth’s natural magnetic field and cause geomagnetic storms. Such storms can trigger the aurora or even power outages, and other types of solar activity can cause communications problems, disrupt satellite electronics and even endanger astronauts — especially beyond the protective bubble of Earth’s magnetic field.



Animation above: The solar wind, the Sun’s outflow of material, along with one-off eruptions of solar material called coronal mass ejections carry the Sun’s magnetic field out through the heliosphere, producing space weather effects on Earth and other worlds. Animation Credits: NASA’s Goddard Space Flight Center/Scientific Visualization Studio/Greg Shirah.


Other worlds in our solar system experience their own versions of these effects, and far beyond the planets, the Sun’s material butts up against the interstellar medium, which fills the space between the stars. The interaction in this region plays a role in how often high-energy galactic cosmic rays shoot into our solar system. All of these effects result from complicated systems — but they all start back at the Sun, making it critical to grasp the fundamental physics that drive our star’s activity.


Parker Solar Probe is designed to address three major questions about the physics of the Sun. First: How is the Sun’s outer atmosphere, the corona, heated to temperatures about 300 times higher than the visible surface below? Second — how is the solar wind accelerated so quickly to the high speeds we observe? And finally, how do some of the Sun’s most energetic particles rocket away from the Sun at more than half the speed of light?


“Parker Solar Probe is providing us with the measurements essential to understanding solar phenomena that have been puzzling us for decades,” said Nour Raouafi, Parker Solar Probe project scientist at the Johns Hopkins University Applied Physics Lab in Laurel, Maryland. “To close the link, local sampling of the solar corona and the young solar wind is needed and Parker Solar Probe is doing just that.”


Parker’s instruments are designed to look at these phenomena in question in ways that haven’t been possible before, giving scientists the opportunity to make new strides in the study of the solar atmosphere.


For instance, Parker Solar Probe’s imagers, in the WISPR suite, will have a new perspective on the young solar wind, capturing a view of how it evolves as Parker Solar Probe travels through the solar corona.


The spacecraft’s ISʘIS suite will help scientists dig down into the causes of energetic particle acceleration. Right now, theories diverge on how solar energetic particles are accelerated within the thin shock wave structures usually driven by fast coronal mass ejections — but energetic particle measurements gathered as the spacecraft travels through such waves will help shed light on this problem.


The electric field antennas of the spacecraft’s FIELDS instrument suite can pick up radio bursts that could shed light on the causes of coronal heating.



Image above: This image from Parker Solar Probe’s WISPR (Wide-field Imager for Solar Probe) instrument shows a coronal streamer, seen over the east limb of the Sun on Nov. 8, 2018, at 1:12 a.m. EST. Coronal streamers are structures of solar material within the Sun’s atmosphere, the corona, that usually overlie regions of increased solar activity. The fine structure of the streamer is very clear, with at least two rays visible. Parker Solar Probe was about 16.9 million miles from the Sun’s surface when this image was taken. The bright object near the center of the image is Mercury, and the dark spots are a result of background correction. Image Credits: NASA/Naval Research Laboratory/Parker Solar Probe.


The Solar Probe Cup instrument — which extends beyond the spacecraft’s heat shield and is exposed to the full solar environment — measures the thermal properties of different ion species in the solar wind. Coupled with data from the FIELDS suite, these measurements could help reveal how the solar wind is heated and accelerated.


The science team also expects to be surprised by some of what they learn.


“We don’t know what to expect so close to the Sun until we get the data, and we’ll probably see some new phenomena,” said Raouafi. “Parker is an exploration mission — the potential for new discoveries is huge.”


Parker Solar Probe’s reports indicate that good science data was collected during the first solar encounter, and the data itself began downlinking to Earth on Dec. 7. Because of the relative positions of Parker Solar Probe, the Sun and Earth and their effects on radio transmission, some of the science data from this encounter will not downlink until after the mission’s second solar encounter in April 2019.



Parker Solar Probe at the Sun. Animation Credit: NASA

The mission team did get a chance for some real-world instrument tests during Parker Solar Probe’s Venus flyby in September 2018. Parker Solar Probe made a close pass at the planet while performing a gravity assist to draw its orbit closer to the Sun. Though not expected to study the environment around Venus, Parker’s instruments successfully recorded data, giving scientists an early look at what their instruments are capable of in the harsh environment of space.


As the newest addition to NASA’s fleet of heliophysics missions, Parker Solar Probe works alongside prolific solar and heliospheric research satellites like NASA’s Solar Dynamics Observatory, the Solar and Terrestrial Relations Observatory and the Advanced Composition Explorer. For years — or decades, in some cases — these observatories have scrutinized the Sun and its outflowing material, changing the way we see our star. But they are limited by where they live.


Even as Parker uncovers new information, scientists working with its data will rely on the rest of NASA’s heliophysics fleet to put those details in context.


“Parker Solar Probe is going to a region we’ve never visited before,” said Terry Kucera, a solar physicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Meanwhile, from a distance, we can observe the Sun’s corona, which is driving the complex environment around Parker Solar Probe.”



Animation above: This video clip shows actual data from NASA’s Solar and Terrestrial Relations Observatory Ahead (STEREO-A) spacecraft, along with the location of Parker Solar Probe as it flies through the Sun’s outer atmosphere during its first solar encounter phase in November 2018. Such images will allow us to provide key context for understanding Parker Solar Probe’s observations. Image Credits: NASA/STEREO.


The distinct perspectives of these observatories should be a boon for contextualizing Parker’s observations. While SDO is in geosynchronous Earth orbit, STEREO orbits the Sun at slightly less than 1 AU — one astronomical unit is the average distance between Earth and the Sun — making it just a little bit faster than Earth. That means STEREO usually observes the Sun from a different angle than we do here on Earth. Along with Parker’s measurements close to the Sun and often from a different angle than any of our other satellites, this will give scientists a fuller picture of how solar events change and develop as they propagate out into the solar system.


“The STEREO mission is all about observing the heliosphere from different locations and Parker is a part of that – making measurements from a perspective we’ve never had before,” said Kucera.


Modeling is another critical tool for painting the complete picture around Parker’s observations.


“Our simulation results provide a way to interpret both the localized measurements from the in situ instruments, like FIELDS and SWEAP, as well the more global images produced by WISPR,” said Pete Riley, a research scientist at Predictive Science Inc., in San Diego, California.



Image above: Parker Solar Probe will give scientists another new perspective on the Sun, joining those from other Sun-observing spacecraft. Image Credits: NASA’s Goddard Space Flight Center.


Models are a good way to test theories about the underlying physics of the Sun. By creating a simulation that relies on a certain mechanism to explain coronal heating — for instance, a certain kind of plasma wave called an Alfvén wave — scientists can check the model’s prediction against actual data from Parker Solar Probe to see if they line up. If they do, that means the underlying theory may be what’s actually happening.


“We’ve had a lot of success predicting the structure of the solar corona during total solar eclipses,” said Riley. “Parker Solar Probe will provide unprecedented measurements that will further constrain the models and the theory that’s embedded within them.”


Parker Solar Probe is in a unique position to help improve models — in part because of its record-breaking speed.


The Sun rotates about once every 27 days as viewed from Earth, and the solar structures that drive much of its activity move along with it. That creates a problem for scientists, who can’t always tell if the variability they see is driven by actual changes to the region producing the activity — temporal variation — or is caused by simply receiving solar material from a new source region — spatial variation.



Animation above: Numerical models provide a global context for interpreting Parker Solar Probe observations. This animation is from a model showing how the solar wind flows out from the Sun, with the perspective of Parker Solar Probe’s WISPR instrument overlaid. Animation Credits: Predictive Science Inc.


For part of its orbit, Parker Solar Probe will outrun that problem. At certain points, Parker Solar Probe is traveling fast enough to almost exactly match the Sun’s rotational speed, meaning that Parker “hovers” over one area of the Sun for a short amount of time. Scientists can be certain that changes in data during this period are caused by actual changes on the Sun, rather than the Sun’s rotation.


Parker Solar Probe is part of NASA’s Living with a Star program to explore aspects of the Sun-Earth system that directly affect life and society. The Living with a Star program is managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland, for NASA’s Science Mission Directorate in Washington. APL designed, built and operates the spacecraft.


Related links:


Solar Dynamics Observatory (SDO): https://www.nasa.gov/mission_pages/sdo/main/index.html


Solar and Terrestrial Relations Observatory (STEREO): https://www.nasa.gov/mission_pages/stereo/main/index.html


Advanced Composition Explorer (ACE): https://solarsystem.nasa.gov/missions/ace/in-depth/


Parker Solar Probe: https://www.nasa.gov/solarprobe


Animations (mentioned), Images (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Sarah Frazier.


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Roman Minerva figurine, Bronze Age gold bulla among ‘treasures’ found by UK...

An ancient statue uncovered in a margarine tub is among the treasures revealed to the world by the British public. The figure of Roman deity Minerva was rediscovered languishing in a container by a hobbying metal detectorist.











Roman Minerva figurine, Bronze Age gold bulla among 'treasures' found by UK detectorists
The ancient statuette of the Roman goddess Minerva [Credit: British Museum/PA]

Gold jewellery plucked from the Shropshire marshes, and a priceless antique lamp were also lifted from the Thames by passionate treasure hunters.


The army of hobbyists uncovering treasures – 1,267 treasure finds in 2017 – have been praised for increasing the nation’s knowledge of the past.


Arts minister Michael Ellis thanked the public for their contributions as he announced the figures from the Portable Antiquities Annual report.


A total of 78,000 archaeological items, some classified as treasure, were logged in 2017 alone – and 93% of these were found by metal detectorists.


Objects like the statute of Minerva have been brought to light in remarkable circumstances.











Roman Minerva figurine, Bronze Age gold bulla among 'treasures' found by UK detectorists
The Minerva statuette was found in a margarine tub in a farmer’s kitchen
[Credit: Rod Trevaskus/Oxfordshire County Council/PA]

Metal detectorist Len Jackman, 66, found the Romano-British bronze piece neglected in a margarine tub of artefacts at a farmer friend’s house in rural Oxfordshire.


The unvalued statue had been in the tub for years before Jackman noticed it and took it to be assessed.


He said: “It was in this margarine tub, in a room by the kitchen. I thought it was something. I was going to get my own finds valued, and he said ‘you might as well take that as well’. I said ‘I think you’ll be getting a phone call’.


“You could see it was Roman. You could tell by the weight. There is a thrill. When you’ve found something, you could be the first person to hold something in thousands of years.”











Roman Minerva figurine, Bronze Age gold bulla among 'treasures' found by UK detectorists
The Bronze Age gold bulla (front) discovered in Shropshire [Credit: British Museum’s Portable Antiquities Scheme]

The thrill has driven 1.5% of the UK population to take part in metal detecting, according to the arts minister.


Such enthusiasts have found a Bronze age gold bulla in the Shropshire marshes, which has been dated at 3,500 years old, and a lamp originating in Africa which made its way to Roman-era Britain was dredged from the Thames by mudlarks.


Mr Ellis welcomed their work and announced that a consultation would take place on how to accommodate the increasing numbers of antiquities being unearthed by a growing number of enthusiasts.


Speaking at the British Museum, he said: “Being out of the House Of Commons is a good thing at the moment. We have quite a few fossils over there. Whether they would be classified as treasures is another thing altogether.











Roman Minerva figurine, Bronze Age gold bulla among 'treasures' found by UK detectorists
The Bronze Age gold bulla (front) discovered in Shropshire [Credit: British Museum’s Portable Antiquities Scheme]

“The Roman statue of Minerva found in a food container. It was found by knowledge. That expertise has enriched us all. I want to thank everyone involved in the treasure process. It brings home to me how close we are to the people of the past. We can relate to them.”


The minister called on those involved with unearthing treasures to suggest ways to improve the system by which they are officially recorded, as the numbers taking part in metal detecting have reached a reported 1.5% of the population.


Norfolk was the county which recorded the most finds by those searching for objects, followed by Lincolnshire then Suffolk.


Author: Craig Simpson | Source: Press Association [December 11, 2018]



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Roman-era mosaic left underneath dumpster in Turkey

A Roman-era mosaic has been sitting under a dumpster since its discovery two years in the northwestern Turkish province of Bursa’s İznik (Greek Nikaia) district during municipal works due to a disagreement between the owner of the land and authorities.











Roman-era mosaic left underneath dumpster in Turkey
Credit: Hurriyet Daily News

“This Roman-era mosaic should not be left this way,” said the former director of İznik Museum, Taylan Sevil, who is urging authorities to take action.


The two-metre-square floor mosaic was unearthed in 2015 during sewage works by the municipality in the Beyler neighbourhood. Depicting a human face, the mosaic was examined and revealed to date back to the Roman era.


Archaeologists, widening the soil layer around the mosaic by about 1 square metre, found that the mosaic continued with snake figures on it underneath a nearby house.


The mosaic was unearthed after rescue excavations were initiated under the coordination of the Culture and Tourism Ministry and İznik Museum.


Following the discovery of the mosaic, the area was registered as a first degree site, elevated from its previous recognition as a third degree site. But excavations came to a halt due to the dispute with the owner of the land where the mosaic is.


Having failed to reach a conclusion, authorities covered the mosaic with geotextile material and had sand poured on it.


The İznik Municipality completed the sewage works and laid asphalt on the road after three months. During the works, the area where the mosaic was found was asphalted, too, stirring further fury.


By the order of then-Culture and Tourism Minister Mahir Ünal, the asphalt on the mosaic was removed and pontoons were placed around it.


But the anger hasn’t defused. A dumpster was brought on top of it and the pontoons were removed.


“This Roman-era floor mosaic continues toward underneath a house which has a garden. This important artifact cannot be left this way. Unfortunately, there is a dumpster atop such a big mosaic. The mosaic dates back to the 3rd century AD and it is a unique finding in İznik. It shows us that noble Greek families lived in this region in the Roman era,” he said.


Source: Hurriyet Daily News [December 11, 2018]



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2018 excavation season at Mazotos Shipwreck completed

The Department of Antiquities, Ministry of Transport, Communications and Works, announced the successful completion of the seventh full excavation season at the 4th century BC Mazotos shipwreck was successfully completed, after four weeks of intensive fieldwork (20 September -21 October 2018). The project is conducted by the Maritime Archaeological Research Laboratory (MARELab) of the Archaeological Research Unit, University of Cyprus, in collaboration with the Department of Antiquities of Cyprus, under the direction of Dr Stella Demesticha, Associate Professor in the Department of History and Archaeology. The photogrammetric mapping of the site was coordinated by Dr Dimitrios Skarlatos, Assistant Professor in the Department of Civil Engineering and Geomatics, Cyprus University of Technology.











2018 excavation season at Mazotos Shipwreck completed
A diver recording the amphorae at the Mazotos site [Credit: Department of Antiquities, Republic of Cyprus]

The objective of this year’s field season was to continue and complete the excavation of the bow area of the ancient ship. A total of seventy (70) partly or fully preserved Chian amphorae were recovered, which raised the number of amphorae stowed under the foredeck of the ship’s hold to ninety nine (99). Most of these amphorae were most probably carrying wine but at least one was full of olive pits, possibly for consumption by the crew. Also, two fishing weights were found, which offer us a glimpse of the life onboard the merchantmen of the period.











2018 excavation season at Mazotos Shipwreck completed
Chian amphorae at the Mazotos site [Credit: Department of Antiquities, Republic of Cyprus]

Underneath the cargo, the wooden hull was poorly preserved, most probably (as a result of the wrecking episode and (the subsequent natural site formation processes at play. Only two days prior to the end of the season, a much better preserved part of the hull began to appear, which is a promising indication that more coherent evidence on shipbuilding technology will be found during the next field season. After careful study of the excavated timbers, however, a very important element of shipbuilding technology has already come to light: both ligatures and mortise-and-tenons were used to join the garboard, the stempost and the keel.











2018 excavation season at Mazotos Shipwreck completed
More than 500 amphorae from the Mazotos shipwreck in situ [Credit: Department of Antiquities, Republic of Cyprus]

Related with the traditions of two prominent Mediterranean seafaring people, the Greeks and the Phoenicians, these two techniques found in the same ship add an important piece to the puzzle that is the history of classical shipbuilding in the eastern Mediterranean. This history has thus far been grounded on only two excavated shipwrecks: the Ma’agan Michael, Israel, dated to the end of the fifth century BC and the Kyrenia shipwreck, Cyprus, dated to the beginning of the third century BC. Thus, the Mazotos shipwreck, dated to the fourth century BC, fits right between these two and covers a gap in the development of naval technology in antiquity.
The research team was comprised of 43 members (archaeologists, divers and students), most of them volunteers from Cyprus and eight different countries: Greece, UK, Spain, USA, Italy, Slovenia, Poland and Germany. The project was funded by the Honor Frost Foundation, CYTAVISION, the THETIS Foundation and the University of Cyprus.


Source: Department of Antiquities, Republic of Cyprus [December 12, 2018]



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