четверг, 23 января 2020 г.

Caught “Pink-Handed”

Credit: ESO

The Milky Way contains many regions of starbirth — areas where new stars are springing to life within collapsing clumps of gas and dust. One such region, named Gum 26, is shown here as imaged by the FORS instrument on ESO’s Very Large Telescope in Chile.

Gum 26 is located roughly 20,000 light-years away in the southern constellation of Vela (The Sails). It is something known as an HII region or  emission nebula, where the intense ultraviolet radiation streaming from newly-formed stars ionises the surrounding hydrogen gas, causing it to emit a faint pinkish glow. By catching new stars “pink-handed” in this manner, astronomers can learn more about the conditions under which stars arise, and study how they influence their cosmic environment. 

This image was created as part of the ESO Cosmic Gems programme, an outreach initiative to produce images of interesting, intriguing or visually attractive objects using ESO telescopes, for the purposes of education and public outreach. The programme makes use of telescope time that cannot be used for science observations. All data collected may also be suitable for scientific purposes, and are made available to astronomers through ESO’s science archive.

Source:  ESO/potw

* This article was originally published here

A chronicle of giant straight-tusked elephants

About 800,000 years ago, the giant straight-tusked elephant Palaeoloxodon migrated out of Africa and became widespread across Europe and Asia.

A chronicle of giant straight-tusked elephants
Reconstructed life appearance of the extinct European straight-tusked elephant Palaeoloxodon antiquus
in (top) side and (bottom) frontal view, based on remains uncovered from the Neumark-Nord 1 site
 in Saxony-Anhalt, Germany [Credit: Hsu Shu-yu]
It divided into many species, with distinct types in Japan, Central Asia and Europe -- even some dwarf forms as large as a small donkey on some Mediterranean islands.

In a new study by scientists in Spain, Italy and the UK, including University of Bristol PhD student Hanwen Zhang, published in the journal, Quaternary Science Reviews, some order has been brought into our understanding of all these species.

The most intriguing feature of the straight-tusked elephant, apart from its absolutely enormous size, is the massive, headband-like crest on the skull roof which projects down the forehead. When the celebrated Victorian Scottish geologist Hugh Falconer studied the first fossil skull of Palaeoloxodon found in India, he remarked that the head seemed 'so grotesquely constructed that it looks the caricature of an elephant's head in a periwig'.

For a long time, palaeontologists thought that the European species, Palaeoloxodon antiquus, had a rather slenderly built skull roof crest; whereas the Indian species Palaeoloxodon namadicus, is characterised by an extremely robust skull crest that extends near to the base of the trunk from the top of the skull.

But some Palaeoloxodon skulls, found in Italy and Germany, with almost the same exaggerated skull crest as the Indian form, led a few experts into suspecting these might all be single species.

Hanwen Zhang, who is based in Bristol's School of Earth Sciences, said: "Just like modern elephants, Palaeoloxodon went through six sets of teeth in their lifetimes. This means we can tell the age of any individual with confidence by looking at its fossilised teeth.

"When we looked at a series of skulls from Italy, Germany and India, we found a consistent pattern: the skull crest developed from being very small, not protruding beyond the forehead in juveniles to being larger and more protruding in young adults, eventually becoming very stout in aged adults."

The study's lead author, Asier Larramendi, an independent researcher from Spain, added: "As I plotted various skull and limb bone measurements for these incredible prehistoric elephants, it became clear that the Indian Palaeoloxodon form a distinct group from the European ones; even in European skulls with quite pronounced crests, the skull roof never becomes as thickened as in the Indian specimens.

"This tells us we once had two separate species of these enormous elephants in Europe and India.

"Besides the funky skull roof crest, the head of the straight-tusked elephant is also remarkable for being huge, the largest of any elephant ever - some 4.5 feet from the top of the skull roof to the base of the tusk sheaths!

"Therefore, the skull crest probably evolved to provide additional attachment areas for extra neck muscles, so the animal did not fall on its head."

Hanwen Zhang said: "Having gotten to the bottom of the antiquus/namadicus problem, it then became apparent that other fossil skull materials found in Asia and East Africa represent distinct, possibly more evolutionarily conservative species of Palaeoloxodon.

"Even in fully mature adults with the last set of teeth in place, the skull roof crest remains comparatively unpronounced. This is the case with the earliest Palaeoloxodon from Africa, some Asian species retained this condition."

Source: University of Bristol [January 21, 2020]

* This article was originally published here

New research finds Earth's oldest asteroid strike linked to 'big thaw'

Curtin University scientists have discovered Earth's oldest asteroid strike occurred at Yarrabubba, in outback Western Australia, and coincided with the end of a global deep freeze known as a Snowball Earth.

New research finds Earth's oldest asteroid strike linked to 'big thaw'
The Yarrabubba Impact Structure
[Credit: Google Earth]
The research, published in the leading journal Nature Communications, used isotopic analysis of minerals to calculate the precise age of the Yarrabubba crater for the first time, putting it at 2.229 billion years old - making it 200 million years older than the next oldest impact.

Lead author Dr Timmons Erickson, from Curtin's School of Earth and Planetary Sciences and NASA's Johnson Space Center, together with a team including Professor Chris Kirkland, Associate Professor Nicholas Timms and Senior Research Fellow Dr Aaron Cavosie, all from Curtin's School of Earth and Planetary Sciences, analysed the minerals zircon and monazite that were 'shock recrystallized' by the asteroid strike, at the base of the eroded crater to determine the exact age of Yarrabubba.

The team inferred that the impact may have occurred into an ice-covered landscape, vaporised a large volume of ice into the atmosphere, and produced a 70km diameter crater in the rocks beneath.

Professor Kirkland said the timing raised the possibility that the Earth's oldest asteroid impact may have helped lift the planet out of a deep freeze.

"Yarrabubba, which sits between Sandstone and Meekatharra in central WA, had been recognised as an impact structure for many years, but its age wasn't well determined," Professor Kirkland said.

New research finds Earth's oldest asteroid strike linked to 'big thaw'
Researchers analysed 'shock crystallized' zircon to determine
the exact age of Yarrabubba [Credit: Curtin University]
"Now we know the Yarrabubba crater was made right at the end of what's commonly referred to as the early Snowball Earth - a time when the atmosphere and oceans were evolving and becoming more oxygenated and when rocks deposited on many continents recorded glacial conditions".

Associate Professor Nicholas Timms noted the precise coincidence between the Yarrabubba impact and the disappearance of glacial deposits.

"The age of the Yarrabubba impact matches the demise of a series of ancient glaciations. After the impact, glacial deposits are absent in the rock record for 400 million years. This twist of fate suggests that the large meteorite impact may have influenced global climate," Associate Professor Timms said.

"Numerical modelling further supports the connection between the effects of large impacts into ice and global climate change. Calculations indicated that an impact into an ice-covered continent could have sent half a trillion tons of water vapour - an important greenhouse gas - into the atmosphere. This finding raises the question whether this impact may have tipped the scales enough to end glacial conditions."

Dr Aaron Cavosie said the Yarrabubba study may have potentially significant implications for future impact crater discoveries.

"Our findings highlight that acquiring precise ages of known craters is important - this one sat in plain sight for nearly two decades before its significance was realised. Yarrabubba is about half the age of the Earth and it raises the question of whether all older impact craters have been eroded or if they are still out there waiting to be discovered," Dr Cavosie said.

Author: Lucien Wilkinson | Source: Curtin University [January 22, 2020]

* This article was originally published here

Warm-blooded crocs thrived in Jurassic cold snap

They are revered throughout nature as chilling predators … now research shows crocodiles have not always been the cold-blooded creatures they are today.

Warm-blooded crocs thrived in Jurassic cold snap
Metriorhynchus superciliosus [Credit: Martin Fritzlar, Flickr]
Scientists who analysed fossil teeth belonging to some of the species' ancient ancestors say at least one type of prehistoric crocodile was warm-blooded.

Body temperature

The findings suggest the animals—called metriorhynchids—could raise their body temperature to stay warm in falling temperatures in a manner similar to modern-day birds and mammals.

Researchers say this likely enabled the animals, which lived during the Jurassic and Cretaceous periods, to thrive during a spell of global cooling around 150 million years ago. Their cold-blooded cousins, by contrast, struggled to adapt but ultimately survived.

Being warm-blooded was key to metriorhynchids evolving a dolphin-like body—including flippers and a tail fin—and venturing out to live in the open oceans, the scientists say.

Fossil teeth

A team of palaeontologists, including researchers from Edinburgh, analysed the mineral make-up of teeth from metriorhynchids and a closely related family known as teleosaurids.

Oxygen levels in the fossil tooth enamel were affected by the animals' body temperature, and measuring them enabled researchers to discover whether they were cold- or warm-blooded.

Jurassic Period

Their analysis shows that metriorhynchids could raise their body temperature above that of the surroundings by using their metabolism to generate heat, meaning they were warm-blooded.

While they were less efficient at heating themselves than most other warm-blooded animals, their adaptability likely helped them survive when sea temperatures dropped at the end of the Jurassic Period.

Teleosaurids were cold-blooded, the researchers found, and kept warm in the same way as modern crocodiles—by basking in the sun. They may have struggled to stay warm when sea temperatures fell, which could partly explain why many of them died out at the end of the Jurassic Period.

"This discovery helps us better understand these bizarre crocs. They rapidly changed from animals looking similar to modern long-snouted crocodiles, to ones with flippers, a tail fin and massive, forward-facing eyes. Their transition from land to sea dwellers increasingly mirrors the better-known transformation undergone by dolphins and whales millions of years ago," says Dr. Mark Young.

The findings are published in Philosophical Transactions of the Royal Society B: Biological Sciences.

Source: University of Edinburgh [January 22, 2020]

* This article was originally published here

2020 January 23 Globular Star Cluster NGC 6752 Image Credit...

2020 January 23

Globular Star Cluster NGC 6752
Image Credit & Copyright: Jose Joaquin Perez

Explanation: Some 13,000 light-years away toward the southern constellation Pavo, the globular star cluster NGC 6752 roams the halo of our Milky Way galaxy. Over 10 billion years old, NGC 6752 follows clusters Omega Centauri and 47 Tucanae as the third brightest globular in planet Earth’s night sky. It holds over 100 thousand stars in a sphere about 100 light-years in diameter. Telescopic explorations of the NGC 6752 have found that a remarkable fraction of the stars near the cluster’s core, are multiple star systems. They also reveal the presence of blue straggle stars, stars which appear to be too young and massive to exist in a cluster whose stars are all expected to be at least twice as old as the Sun. The blue stragglers are thought to be formed by star mergers and collisions in the dense stellar environment at the cluster’s core. This sharp color composite also features the cluster’s ancient red giant stars in yellowish hues. (Note: The bright, spiky blue star at 11 o'clock from the cluster center is a foreground star along the line-of-sight to NGC 6752)

∞ Source: apod.nasa.gov/apod/ap200123.html

* This article was originally published here

Study reveals pre-Hispanic history, genetic changes among indigenous Mexican populations

As more and more large-scale human genome sequencing projects get completed, scientists have been able to trace with increasing confidence both the geographical movements and underlying genetic variation of human populations. Most of these projects have favoured the study of European populations, and thus, have been lacking in representing the true ethnic diversity across the globe.

Study reveals pre-Hispanic history, genetic changes among indigenous Mexican populations
To better understand the broad demographic history of pre-Hispanic Mexico and to search for signatures of adaptive
evolution, an international team led by Mexican scientists have sequenced the complete protein-coding regions
of the genome, or exomes, of 78 individuals from different indigenous groups from Mexico. The genomic study
 is the largest of its kind for indigenous populations from the Americas [Credit: Ruben Mendoza,
National Laboratory of Genomics for Biodiversity (LANGEBIO) - UGA, CINVESTAV]
To better understand the broad demographic history of pre-Hispanic Mexico and to search for signatures of adaptive evolution, an international team led by Mexican scientists have sequenced the complete protein-coding regions of the genome, or exomes, of 78 individuals from five different indigenous groups from Northern (Rara?muri or Tarahumara, and Huichol), Central (Nahua), South (Triqui, or TRQ) and Southeast (Maya, or MYA) Mexico. The genomic study, the largest of its kind for indigenous populations from the Americas, appeared recently in the advanced online edition of Molecular Biology and Evolution.

"We modeled the demographic history of indigenous populations from Mexico with northern and southern ethnic groups (Tarahumara and Huichol) splitting 7.2 kya and subsequently diverging locally 6.5 kya (Huichol groups) and 5.7 kya (Triqui and Maya), respectively," said lead author Maria Avila-Arcos, of the National Autonomous University of Mexico. The Nahua were excluded from the final analysis due to the noise it brought to the overall analysis.

Overall, they identified 120,735 single nucleotide variants (SNV) among the individuals studied, which were used to trace back the population history. Furthermore, they were able to reconcile their data with the demographic history and fossil records of ancestral Native Americans.

"The split times we found are also coherent with previous estimates of ancestral Native Americans diverging ~17.5-14.6 KYA into Southern Native Americans or "Ancestral A," comprising Central and Southern Native Americans) and Northern Native Americans or "Ancestral B," and with an initial settlement of Mexico occurring at least 12,000 years ago, as suggested by the earliest skeletal remains dated to approximately this age found in Central Mexico and the Yucatan peninsula," said Avila-Arcos. "Studies on genome-wide data from ancient remains from Central and South America reveal genetic continuity between ancient and modern populations in some parts of the Americas over the last 8,500 years."

"This suggests that, by that time, the ancestral population of MYA was not yet genetically differentiated from others, so our estimates of northern/southern split at 7.2 KYA and Mayan/Triqui divergence at 5.7 KYA fit with this scenario."

Next, they scanned the data to identify candidate genes most important for adaptation.

"Interestingly, some of these genes had previously been identified as targets of selection in other populations," said co-corresponding author Andres Moreno Estrada, principal investigator at National Laboratory of Genomics for Biodiversity (LANGEBIO) - UGA, CINVESTAV.

These genes include SLC24A5, involved in skin pigmentation, and FAP, which was previously suggested to be under adaptive archaic introgression in Peruvians and Melanesians. Three genes were involved in the immune response. These include SYT5, implicated in innate immune response, and interleukins IL17A and IL13. The remaining candidate genes were involved in signal transduction (MPZL1), protein localization and transport (GRASP and ARFRP1), cell differentiation and spermatogenesis (GMCL), Golgi apparatus organization (UBXN2B), neuron differentiation (MANF), signaling and cardiac muscle contraction (ADRBK1), cell cycle (CDK5), microtubule organization and stabilization (NCKAP5L), and stress fiber formation (NCKIPSD).

A couple of genes stood out for the team. These included, BCL2L13, which is highly expressed in skeletal muscle and could be related to physical endurance, including high endurance long-distance running, a well-known trait of the northern Mexico Rara?muri. The KBTBD8 gene has been associated with idiopathic short stature (also found in Koreans) and the team found it to be highly differentiated in Triqui, a southern indigenous group from Oaxaca whose height is extremely low compared to other Native populations.

"We carried out the most comprehensive characterization of potentially adaptive functional variation in Indigenous peoples from the Americas to date," said Moreno Estrada. "We identified in these populations over four thousand new variants, most of them singletons, with neutral, regulatory, as well as protein-truncating and missense annotations. The average number of singletons per individual was higher in Nahua (NAH) and Maya (MYA), which is expected given these two Indigenous groups embody the descendants of the largest civilizations in Mesoamerica, and that today Nahua and Maya languages are the most spoken Indigenous languages in Mexico. Furthermore, the generated data also allowed us to propose a demographic model inferred from genomic data in Native Mexicans and to identify possible events of adaptive evolution in pre-Columbian Mexico."

Source: Oxford University Press [January 22, 2020]

* This article was originally published here

Neutron source enables a look inside dino eggs

Did the chicks of dinosaurs from the group oviraptorid hatch from their eggs at the same time? This question can be answered by the length and arrangement of the embryo's bones, which provide information about the stage of development. But how do you look inside fossilized dinosaur eggs? Paleontologists from the University of Bonn used the neutron source of the Technical University of Munich at the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching. This showed that oviraptorids developed at different speeds in their eggs and that they resemble modern birds in this respect. The results have been published in the journal Integrative Organismal Biology.

Neutron source enables a look inside dino eggs
Reconstruction of a clutch of eggs with silhouettes of the oviraptorids
[Credit: Chien-Hsing Lee/Tzu-Ruei Yang/Thomas Engler]
Until now, researchers have assumed that the two-legged dinosaurs known as oviraptorids, which lived in Central Asia during the Upper Cretaceous (from 88 to 66 million years), should be placed between modern crocodiles and birds with regard to their reproductive biology. Crocodiles bury their eggs and the offspring hatch at the same time. With birds, however, hatching in the nest often happens at different times.

Together with scientists from Taiwan, Switzerland and the Heinz Maier-Leibnitz Zentrum in Garching, paleontologists from the University of Bonn have now investigated how differently the development of embryos in three 67 million years old oviraptorid egg fossils from the Ganzhou Basin of Jiangxi Province in China had progressed. "Oviraptorid eggs are found relatively frequently in Central Asia, but most of them are removed from the context of their discovery," says Thomas Engler from the Institute for Geosciences at the University of Bonn. Often it is then no longer discernible whether the eggs are from a single clutch.

Important find in China

"This is different with the fossils we've examined: We found a pair of eggs and another egg together embedded in a block of rock," reports Dr. Tzu-Ruei Yang, who discovered the unusual find during an excavation near the city of Ganzhou in China. This led the researchers to conclude that the 7-inch (18cm) eggs were laid almost at the same time by a female oviraptorid. Yang completed his doctorate at the Institute for Geosciences at the University of Bonn and now works as a researcher at the National Museum of Natural Sciences in Taiwan.

Neutron source enables a look inside dino eggs
The three oviraptorid eggs studied by scientists at the University of Bonn and the TU Munich
[Credit: W. Schürmann/TU München]

The researchers tried to estimate whether the baby dinosaurs would have hatched at the same time or at different times based on the developmental stage of the embryos in the three eggs. The length of the bones in the egg plays an important role here. "The embryo with comparatively longer bones is more developed," explains Yang. Another indication is the extent to which the bones are connected to each other. A more strongly connected skeleton suggests a higher developmental stage of the dinosaur embryo.

A look inside the dinosaur egg

But how is it possible to determine the position of bones inside a fossilized dinosaur egg? The paleontologists at the University of Bonn initially tried to do this with the institute's own X-ray microcomputer tomograph. "Unfortunately, it was not possible to distinguish the bones from the surrounding rock," says Engler.

Neutron source enables a look inside dino eggs
Right: Neutron tomogram as cross-section through egg 3, scanned at the ANTARES facility. Different bones can be seen
as round, lighter structures, including parts of the pelvis. A 3-D model of the surface of egg 3 can be seen on the left
[Credit: Scan created by Burkhard Schillinger/MLZ]
For this reason, the researchers took the dinosaur eggs to the research neutron source of the Technical University of Munich at the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching. "The high penetration depth of the neutrons at the NECTAR and ANTARES facilities made it possible to visualize the internal structures," says Dr. Malgorzata Makowska, who was in charge of measurements and analyses at the MLZ and is now carrying out research at the Swiss neutron source PSI.

The length and position of the embryo bones led the researchers to conclude that the single egg must have been laid earlier than the pair of eggs in the same clutch. However, the embryos of the pair were also at different developmental stages. Thin sections confirm these results. The researchers used these to measure the thickness of the eggshells. The developing embryo absorbs part of the shell because it needs calcium for its growing skeleton. "The more material is removed from the egg shell, the more advanced the embryo's development," explains Yang.

Neutron source enables a look inside dino eggs
Photogrammetry of egg 3:The object was photographed and reconstructed
from different perspectives [Credit: Jens Lallensack]
On the basis of these indications, the scientists conclude that the reproductive biology of oviraptorids were similar to that of modern birds, whose chicks hatch at different times. The results argue against the strategy of crocodiles or turtles, which all emerge from their eggs at the same time. This has brought the researchers one step closer to the life of the long extinct oviraptorids, who roamed Central Asia on two legs. "Furthermore, the study shows that exploring fossils with neutrons yields novel scientific results," says Engler.

Source: University of Bonn [January 22, 2020]

* This article was originally published here

First ancient DNA from West/Central Africa illuminates deep human past

An international team led by Harvard Medical School scientists has produced the first genome-wide ancient human DNA sequences from west and central Africa.

First ancient DNA from West/Central Africa illuminates deep human past
General view of the excavation of Shum Laka’s rockshelter (Grassfields region of Cameroon). This site was home to a
human population that lived in the region for at least five millennia and bore little genetic relatedness to the people
who live in the region today. Analysis of whole genome ancient DNA data from the people who lived at this site
provided insights into the existence of several never-before-appreciated, early-branching
African human lineages [Credit: Pierre de Maret, January 1994]
The data, recovered from four individuals buried at an iconic archaeological site in Cameroon between 3,000 and 8,000 years ago, enhance our understanding of the deep ancestral relationships among populations in sub-Saharan Africa, which remains the region of greatest human diversity today.

The findings, published in Nature, provide new clues in the search to identify the populations that first spoke and spread Bantu languages. The work also illuminates previously unknown "ghost" populations that contributed small portions of DNA to present-day African groups.

Map of Africa with Cameroon in dark blue and approximate location of Shum Laka marked with star. Image adapted from Alvaro1984 18/Wikimedia Commons

Research highlights:

- DNA came from the remains of two pairs of children who lived around 3,000 years ago and 8,000 years ago, respectively, during the transition from the Stone Age to the Iron Age.

- The children were buried at Shum Laka, a rock shelter in the Grassfields region of northwestern Cameroon where ancient people lived for tens of thousands of years. The site has yielded prolific artifacts along with 18 human skeletons and lies in the region where researchers suspect Bantu languages and cultures originated. The spread of Bantu languages--and the groups that spoke them--over the past 4,000 years is thought to explain why the majority of people from central, eastern and southern Africa are closely related to one another and to west/central Africans.

- Surprisingly, all four individuals are most closely related to present-day central African hunter-gatherers, who have very different ancestry from most Bantu speakers. This suggests that present-day Bantu speakers in western Cameroon and across Africa did not descend from the sequenced children's population.

First ancient DNA from West/Central Africa illuminates deep human past
Excavation of a double burial at the Shum Laka rock shelter (Grassfields region of Cameroon) containing the remains
of two boys who lived ~8,000 years ago and who were genetically from the same family. Ancient DNA reveals that
these two individuals and another pair of children buried five millennia later at Shum Laka were from a stable
 population that was then almost completely displaced by the very different populations living
in Cameroon today [Credit: Isabelle Ribot, January 1994]

- One individual's genome includes the earliest-diverging Y chromosome type, found almost nowhere outside western Cameroon today. The findings show that this oldest lineage of modern human males has been present in that region for more than 8,000 years, and perhaps much longer.

- Genetic analyses indicate that there were at least four major lineages deep in human history, between 200,000 and 300,000 years ago. This radiation hadn't been identified previously from genetic data.

- Contrary to common models, the data suggest that central African hunter-gatherers diverged from other African populations around the same time as southern African hunter-gatherers did.

- Analyses reveal another set of four branching human lineages between 60,000 and 80,000 years ago, including the lineage known to have given rise to all present-day non-Africans.

- The Shum Laka individuals themselves harbor ancestry from multiple deep lineages, including a previously unknown, early-diverging ancestry source in West Africa.

Source: Harvard Medical School [January 22, 2020]

* This article was originally published here


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Channel: Terry's Theories  


Video length: 2:59
Category: Science & Technology

Decorated Sword Hilt, (8th or 9th Century CE), National Museum of Scotland, Edinburgh, December...

Decorated Sword Hilt, (8th or 9th Century CE), National Museum of Scotland, Edinburgh, December 2019.

* This article was originally published here

Late Neolithic Italy was home to complex networks of metal exchange

During the 4th and 3rd millennia BC, Italy was home to complex networks of metalwork exchange, according to a study published in the open-access journal PLOS ONE by Andrea Dolfini of Newcastle University (UK), and Gilberto Artioli and Ivana Angelini of the University of Padova (Italy).

Late Neolithic Italy was home to complex networks of metal exchange
Articulated burial and dismembered human remains from Ponte San Pietro, tomb 22.The chamber tomb is typical of
the Rinaldone burial custom, central Italy, c.3600-2200 BC. Reprinted from Miari 1995 under a CC BY licence,
with permission from Monica Miari, original copyright 1995 [Credit: Dolfini et al, 2020]
Research in recent decades has revealed that copper mining and metalwork in Italy began earlier and included more complex technologies than previously thought. However, relatively little is known about metalwork exchange across the country, especially south of the Alps. In this study, Dolfini and colleagues sought to understand how commonly and how widely copper was imported and exchanged throughout Late Neolithic (Copper Age) Italy.

The researchers conducted an analysis of 20 copper items, including axe-heads, halberds, and daggers, from central Italy dating to the Copper Age, between 3600 and 2200 BC. Comparing archaeological data and chemical signatures of these items to nearby sources of copper ore, as well as to other prehistoric sites, they were able to determine that most of the examined objects were cast from copper mined in Tuscany, with the rest sourced from the western Alps and possibly the French Midi.

Late Neolithic Italy was home to complex networks of metal exchange
Map of the sites mentioned in the article
[Credit: Dolfini et al. 2020]

These results not only confirm the importance of the Tuscan region as a source of copper for Copper Age communities in Italy, reaching as far as the Tyrolean area home of the Alpine Iceman, but also reveal the unexpected finding that non-Tuscan copper was a significant import to the region at this time. These data contribute to a growing picture of multiple independent networks of Copper Age metal exchange in the Alps and neighboring regions. The authors note that future research might uncover other early sources of copper, as well as more details of the interactions between these early trade networks.

The authors add: "The first systematic application of lead isotope analysis (a geological sourcing technique) to Copper Age metal objects from central Italy, 3600-2200 BC, has shed new light on the provenance of the copper used to cast them. The research has revealed that, while some of the copper was sourced from the rich ore deposits of Tuscany, as was expected, some is from further afield. This unforeseen discovery demonstrates that far-reaching metal exchange networks were in operation in prehistoric Europe over a thousand years before the Bronze Age."

Source: Public Library of Science [January 22, 2020]

* This article was originally published here

Viking Boat Carving (Jarlshof), National Museum of Scotland, Edinburgh, December 2019.

Viking Boat Carving (Jarlshof), National Museum of Scotland, Edinburgh, December 2019.

* This article was originally published here

Domesticated wheat has complex parentage

Certain types of domesticated wheat have complicated origins, with genetic contributions from wild and cultivated wheat populations on opposite sides of the Fertile Crescent. Terence Brown and colleagues at the University of Manchester report these findings in a new paper published in the open-access journal PLOS ONE.

Domesticated wheat has complex parentage
Credit: WikiCommons
A wild form of wheat called emmer wheat was one of the first plant species that humans domesticated. Emmer is not grown widely today, but gave rise to the durum wheat used for pasta and hybridized with another grass to make bread wheat, so its domestication was an important step in the transition from hunting and gathering to agriculture.

While the archaeological record suggests that cultivation began in the southern Levant region bordering the eastern edge of the Mediterranean Sea around 9,500 years ago, genetic studies point to an origin in the northern region of the Fertile Crescent, in what is now Turkey. To clarify emmer's origins, researchers screened 189 types of wild and domesticated wheats and used the more that 1 million genetic variations that they identified to piece together the genetic relationships between different kinds of wheat.

Based on the analysis, the researchers propose that an emmer crop, which humans cultivated but had not yet domesticated, spread from the southern Levant to southeast Turkey, where it mixed with a wild emmer population and ultimately yielded the first domesticated variety. The results of this hybridization can be detected in wild emmer plants in Turkey today.

The complex evolutionary relationships between wild emmer and cultivated wheat varieties uncovered by the analysis are similar to the interbreeding that occurred between wild and cultivated populations of other grain crops, such as barley and rice.

The authors add: "We used next-generation DNA sequencing technologies to detect hundreds of thousands of variants in the genomes of wild and cultivated emmer wheat, giving us an unprecedented insight into the complexity of its domestication process. The patterns we observed do not fit well with a simplistic model of fast and localized domestication event but suggest instead a long process of cultivation of wild wheat by hunter-gatherer communities connected throughout the Fertile Crescent, prior to the emergence of a fully domesticated wheat form."

Source: Public Library of Science [January 22, 2020]

* This article was originally published here


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